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  • 1168401.
    Zhang, Shanshan
    et al.
    Umeå University, Faculty of Social Sciences, Center for Environmental and Resource Economics (CERE).
    Lundgren, Tommy
    Umeå University, Faculty of Social Sciences, Center for Environmental and Resource Economics (CERE).
    Zhou, Wenchao
    Umeå University, Faculty of Social Sciences, Centre for Regional Science (CERUM).
    Energy efficiency in Swedish Industry: A firm-level data envelopment analysis2016In: Energy Economics, ISSN 0140-9883, E-ISSN 1873-6181, Vol. 55, p. 42-51Article in journal (Refereed)
    Abstract [en]

    This paper assesses energy efficiency in Swedish industry. Using unique firm-level panel data covering the years 2001–2008, the efficiency estimates are obtained for firms in 14 industrial sectors by using data envelopment analysis (DEA). The analysis accounts for multi-output technologies where undesirable outputs are produced alongside with the desirable output. The results show that there was potential to improve energy efficiency in all the sectors and relatively large energy inefficiencies existed in small energy-use industries in the sample period. Also, we assess how the EU ETS, the carbon dioxide (CO2) tax and the energy tax affect energy efficiency by conducting a second-stage regression analysis. To obtain consistent estimates for the regression model, we apply a modified, input-oriented version of the double bootstrap procedure of Simar and Wilson (2007). The results of the regression analysis reveal that the EU ETS and the CO2 tax did not have significant influences on energy efficiency in the sample period. However, the energy tax had a positive relation with the energy efficiency.

  • 1168402.
    Zhang, Shasha
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Device aggregation with data networking: Implementing a Personal Area Network2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Technology is advancing rapidly and intelligent devices are becoming affordable and wireless infrastructure is becoming pervasive. Personal information technology appliances have become part of our life, via cellular phones, PDAs, Bluetooth headsets, handheld keyboards, GPS, and digital cameras. In the future, new intelligent devices will be invented as technology evolves. However, because multiple devices provide similar (but different) functionality it is complex for the average user to choose a single device. Moreover, today it is hard to configure, administer, and use several different appliances together. In order to be utilized in an effective manner and in an accessible way, personal devices should be aggregated, i.e., connected together via a local area network so that they can appear to the user as if they were a single device.

    This paper introduces a connection model based on device aggregation to realize shared state, the behavior of a shared appliance, and with the superset of the individual device functionality. Such an aggregated logical device might even exhibit functions which a user would have a very hard time realizing by manually combining devices. This will facilitate the user’s control over their appliances (build of different devices), but acting as one device.

    The project was a joint effort with David Sabaté Mogica. We developed such a system based on Dynamic Host Client protocol (DHCP) and Service Location Protocol (SLP) for service discovery and Virtual Network Computing (VNC) for remote desktop control. The system builds on a laboratory network environment. This thesis concerns the implementation and evaluation of service discovery. The Remote desktop control was researched and implemented separately and will be reported separately. Service discovery between two computers has been implemented using a custom program developed for a PDA. However, at present the PDA only sends a DA request packet with DHCP. However, service discovery has been successfully tested between two computers. This provided an important base for the programming on PDA and the future development of a similar program for a cellular phone.

  • 1168403.
    ZHANG, SHEN
    Jönköping University, School of Engineering, JTH, Product Development.
    USER INTERFACE FOR GENERIC SHIFTER2016Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
  • 1168404.
    Zhang, Sheng
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Barriers for Implementing advanced logistic system in retail: Comparison between Wal-Mart and a Chinese company2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    With the rapid growth of China economy, more and more companies search a way to raise their local business to an international level. Wal-Mart is the best representative of advanced supply chain management. With decades of developing, Wal-Mart establishes an enviable supply chain management with nearly zero inventory and advanced information technology system. Hualian is the biggest supermarket chain in China, who tries to gain competitive advantage from Wal-Mart supply chain pattern. Meanwhile, beside Hualian, Wal-Mart's supply chain pattern is also meaningful to other companies. Hence, trying to figure out how Wal-Mart manages its supply chain is useful. The main purpose is to find out requirement and barriers for implementing Wal-Mart’s advanced logistics system in a Chinese retail company. By comparing Wal-Mart supply chain management with Hualian, this illustration will perfectly make a demonstration for Chinese companies. Since Hualian is the biggest supermarket chain company in China, this comparison is resourceful. This paper will finally illustrate how Wal-Mart does its supply chain management, and what barriers and benefits Chinese companies will meet while implementing. Primary data and secondary data have been used in the comparison. Additionally, qualitative method will be applied for purchasing, and quantitative method will be used for distribution analysis. Although Hualian is the biggest supermarket chain company in China, it still has a distance from Wal-Mart whatever on information system or on scales. Implementing advanced logistic supply chain management eventually will benefit Hualian a lot; however, barriers prior to benefits are huge obstacles for Hualian and its suppliers.

  • 1168405.
    Zhang, Sheng
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Electronics, Mathematics and Natural Sciences.
      GPS/INS Combination for a Beam Tracking System2011Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    In recent years, Land vehicle navigation system (LVNS) technology is a subject of great interest due to its potential for both consumer and business vehicle markets. GPS/INS ( Global Positioning System/ Inertial Navigation System ) integrated system is an effective solution to realize the LVNS. And how to keep communication between the vehicle and satellite while the vehicle is running in a bad environment is the main task in this thesis.

    The thesis provides an introduction to beam tracking system and two algorithms of how to improve the performance, then compare these two algorithms and choose the suitable one and implement it on ArduPilotMega board using Arduino language, at last test the integrated GPS/INS system in practice in order to estimate the performance.

    The requirements of the project are the maximum angular speed and angular acceleration speed of the vehicle are  and , respectively. Two algorithms which are Direction Cosine Matrix (DCM) and Euler Angle are evaluated in the system. In this thesis, there are many rotations due to the hostile environment, and DCM algorithm is not suitable for the requirement according to the results of simulation. Therefore, an innovated method which is Euler Angle Algorithm can be one effective way to solve the probelm.

    The primary idea of Euler Angle algorithm is to calculate the difference between the reference direction vector and the measurement direction vector from GPS and accelerometers, once there is an error rotation, take the cross product and rotate the incorrect direction vector back to original direction. The simulation results show that by implementing EA algorithm, system requirements can be achievable with a 10kHz update rate antenna and a 4000Hz sampling rate gyroscope, also with EA implementation in ArduPilotMega board, the real system tracking ability can be enhanced effectively.

  • 1168406.
    Zhang, Sheng
    et al.
    Nanchang Hangkong Univ, Sch Informat Engn, Nanchang, Peoples R China.;Dalarna Univ, Business Intelligence & Informat, Borlange, Sweden..
    Liu, Xiaodong
    Nanchang Hangkong Univ, Sch Informat Engn, Nanchang, Peoples R China..
    Bao, Xiaoling
    Nanchang Hangkong Univ, Sch Informat Engn, Nanchang, Peoples R China..
    Song, William Wei
    Dalarna University, School of Technology and Business Studies, Information Systems.
    Multilayer and multi-agent data fusion in WSN2015In: Web Information Systems Engineering – WISE 2014 Workshops: 15th International Workshops IWCSN 2014, Org2 2014, PCS 2014, and QUAT 2014, Thessaloniki, Greece, October 12-14, 2014, Revised Selected Papers / [ed] Boualem Benatallah, Azer Bestavros, Barbara Catania, Armin Haller, Yannis Manolopoulos, Athena Vakali, Yanchun Zhang, 2015, Vol. 9051, p. 211-225Conference paper (Refereed)
    Abstract [en]

    In the wireless sensor networks, the hardware limitations of sensor nodes cause high transmission failure rate. We usually increase the density of nodes to improve the quality of information transmission. However, it is difficult for the limited energy supply, storage, and communication bandwidth to transfer large amount of redundant sensory data. So we use data fusion technology to remove the redundant data as much as possible before the data transmission. Data fusion becomes a research hotspot in recent years. In this paper we propose a multilayer and multi-agent data fusion mode, and analyze the proposed mode performance in three aspects: hops, energy consumption and network delay. The simulation experiments show that, if reasonably suitable parameters, such as the network scale, the number and size of agents, the data processing cost, are selected, the mobile agent mode is much better than the client/server mode.

  • 1168407.
    Zhang, Sheng
    et al.
    Nanchang Hangkong Univ, Sch Informat Engn, Nanchang, Peoples R China..
    Wang, Xin
    Nanchang Hangkong Univ, Sch Informat Engn, Nanchang, Peoples R China..
    Yao, Minghui
    Nanchang Hangkong Univ, Sch Informat Engn, Nanchang, Peoples R China..
    Song, William Wei
    Dalarna University, School of Technology and Business Studies, Information Systems. Dalarna Univ, Business Intelligence & Informat, Borlange, Sweden..
    Community-based message transmission with energy efficient in opportunistic networks2016In: Web Information Systems Engineering – WISE 2016: 17th International Conference, Shanghai, China, November 8-10, 2016, Proceedings, Part II, 2016, Vol. 10042, p. 411-423Conference paper (Refereed)
    Abstract [en]

    An Opportunistic Networks is a wireless self-organized network, in which there is no need to build a fixed connectivity between source node and destination node, and the communication depends on the opportunity of node meeting. There are some classical message transmission algorithms, such as PRoPHET, MaxProp, and so on. In the Opportunity Networks with community characteristic, the different message transmission strategies can be sued in inter-community and intra-community. It improves the message successful delivery ratio significantly. The classical algorithms are CMTS and CMOT. We propose an energy efficient message forwarding algorithm (EEMF) for community-based Opportunistic Networks in this paper. When a message is transmitted, we consider not only the community characteristic, but also the residual energy of each node. The simulation results show that the EEMF algorithm can improve the message successful delivery ratio and reduce the network overhead obviously, in comparison with classical routing algorithms, such as PRoPHET, MaxProp, CMTS and CMOT. Meanwhile the EEMF algorithm can reduce the node's energy consumption and prolong the lifetime of network.

  • 1168408.
    Zhang, Shengrui
    et al.
    Hebei Normal University, China.
    Xu, Qinghai
    Hebei Normal University, China.
    Gaillard, Marie-José
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Cao, Xianyong
    Hebei Normal University, China ; Research Unit Potsdam, Germany ; University of Potsdam, Germany.
    Li, Jianyong
    University of Helsinki, Finland.
    Zhang, Liyan
    Shijiazhuang University of Economics, China.
    Li, Yuecong
    Hebei Normal University, China.
    Tian, Fang
    Research Unit Potsdam, Germany ; University of Potsdam, Germany.
    Zhou, Liping
    Peking University, China.
    Lin, Fengyou
    Chinese Academy of Sciences, China.
    Yang, Xiaolan
    Hebei Institute of Geography Science, China.
    Characteristic pollen source area and vertical pollen dispersal and deposition in a mixed coniferous and deciduous broad-leaved woodland in the Changbai mountains, northeast China.2016In: Vegetation History and Archaeobotany, ISSN 0939-6314, E-ISSN 1617-6278, Vol. 25, no 1, p. 29-43Article in journal (Refereed)
    Abstract [en]

    Pollen influx (number of pollen grains cm−2 year−1) can objectively reflect the dispersal and deposition features of pollen within a certain time and space, and is often used as a basis for the quantitative reconstruction of palaeovegetation; however, little is known about the features and mechanisms of vertical dispersal of pollen. Here we present the results from a 5 year (2006–2010) monitoring program using pollen traps placed at different heights from ground level up to 60 m and surface soil samples in a mixed coniferous and deciduous broad-leaved woodland in the Changbai mountains, northeastern China. The pollen percentages and pollen influx from the traps have very similar characteristics to the highest values for Betula,FraxinusQuercus and Pinus, among the tree taxa and Artemisia, Chenopodiaceae and Asteraceae among the herb taxa. Pollen influx values vary significantly with height and show major differences between three distinct layers, above-canopy (≥32 m), within the trunk layer (8 ≤ 32 m) and on the ground (0 m). These differences in pollen influx are explained by differences in (i) the air flows in each of these layers and (ii) the fall speed of pollen of the various taxa. We found that the pollen recorded on the ground surface is a good representation of the major part of the pollen transported in the trunk space of the woodland. Comparison of the pollen influx values with the theoretical, calculated “characteristic pollen source area” (CPSA) of 12 selected taxa indicates that the pollen deposited on the ground surface of the woodland is a fair representation with 85–90 % of the total pollen deposited at a wind speed of 2.4 m s−1 coming from within ca. 1–5 km for Pinus and Quercus, ca. 5–10 km for UlmusTilia, Oleaceae and Betula, ca. 20–40 km for Fraxinus, Poaceae, Chenopodiaceae, Populus andSalix, and ca. 30–60 km for Artemisia; it is also a good representation with 90–98 % of the total pollen deposited coming from within 60 km at a wind speed of 2.4 m s−1, or 100 km at a wind speed: 6 m s−1, for the 12 selected taxa used in the CPSA calculation. Furthermore, comparison with the vegetation map of the area around the sampling site shows that the pollen deposited on the ground represents all plant communities which grow in the study area within 70 km radius of the sampling site. In this study, the pollen percentages obtained from the soil surface samples are significantly biased towards pollen taxa with good preservation due to thick and robust pollen walls. Therefore, if mosses are available instead, soil samples should be avoided for pollen studies, in particular for the study of pollen-vegetation relationships, the estimation of pollen productivities and quantitative reconstruction of past vegetation. The results also indicate that the existing model of pollen dispersal and deposition, Prentice’s model, provides a fair description of the actual pollen dispersal and deposition in this kind of woodland, which suggests that the application of the landscape reconstruction algorithm would be relevant for reconstruction of this type of woodland in the past.

  • 1168409.
    Zhang, Shengzhi
    et al.
    Florida Institute of Technology, Melbourne, FL.
    Makke, Omar
    Ford Motor, Detroit, MI.
    Gusikhin, Oleg Yu
    Ford Motor, Detroit, MI.
    Shah, Ayush
    Ford Motor, Detroit, MI.
    Vasilakos, Athanasios
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Computer Science.
    A security model for dependable vehicle middleware and mobile applications connection2018In: VEHITS 2018: Proceedings of the 4th International Conference on Vehicle Technology and Intelligent Transport Systems / [ed] Gusikhin O.,Helfert M., 2018, p. 379-386Conference paper (Refereed)
    Abstract [en]

    Nowadays automotive industry has been working on the connectivity between automobile and smartphones, e.g., Ford’s SmartDeviceLink, MirrorLink, etc. However, as the interoperability between the smartphone and automotive system increase, the security concern of the increased attack surface bothers the automotive industry as well as the security community. In this paper, we thoroughly study the attack vectors against the novel connection framework between automobile and smartphones, and propose a generic security model to implement a dependable connection to eliminate the summarized attack vectors. Finally, we present how our proposed model can be integrated into existing automotive framework, and discuss the security benefits of our model. Copyright

  • 1168410.
    Zhang, Sherry
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Duke University.
    Seiya, Wolfgang
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology. Duke University.
    3D Printing as an Alternative ManufacturingMethod for the Micro gas Turbine Heat Exchanger2015Student paper other, 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    A variety of materials for high temperature applications were studied. Best materials forconstructing heat exchangers were selected using models based on preferential weights. Currentadditive manufacturing techniques and industries were also studied and rated to determine thebest materialprintingtechniquecombination. Although the rating models do not include everyimportant criterion, the results were expected to be the same if the state of the 3D manufacturingindustries and user preferences do not change. Design recommendations for a compact airtoairheat exchanger were made without considering manufacturing limitations. An economicalassessment of 3D manufacturing techniques was made to determine whether 3D manufacturingcould be a better alternative for heat exchangers. Although very promising, the choice to printheat exchangers with 3D techniques would not be economical at the moment. Future predictionsof the additive manufacturing industry were made having studied related industries.

  • 1168411.
    Zhang, Shi Fu
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Demirtas, Gürcan
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering.
    Miljökravens påverkan inom projektering samt vägproduktion2015Independent thesis Basic level (university diploma), 5 credits / 7,5 HE creditsStudent thesis
    Abstract [en]

    The increased environmental issue which appears more and more in recent times has a major impact on how we build our roads today. Today’s environment demands a controlling part of the working process as well as methods within the elections in the road production. Justifiably demands can achieve a minimized impact on the environment which leads to sustainable development. The national environmental targets are an important guideline to achieve the desired environmental efficiency within road production that all authorities follow.

     

    This thesis explores the foundations of environmental requirements from the Swedish Transport Administration and how this results in entrepreneurs’ approach and its own environmental ambitions.

  • 1168412.
    Zhang, Shi-Jin
    Stockholm University.
    Regulation of Intracellular Calcium in Brown Adipocytes1999Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Intracellular Ca2+ is considered a primary regulator of cell function. In the present study, the control and the effects of intracellular Ca2+ in brown adipocytes have been investigated. Cytosolic Ca2+ levels ([Ca2+]i) are the resultant of the activity of Ca2+ transport systems. Results concerning Ca2+transport systems in the plasma membrane, endoplasmic reticulum and mitochondria are presented.

    [Ca2+]i, monitored with Fura-2/AM, is increased when brown adipocytes are stimulated with norepinephrine (NE). The NE effect is mediated via a1-adrenoceptors and involves both release from intracellular Ca2+ stores and influx of extracellular Ca2+. The NE-induced [Ca2+]i response could be desensitized by pretreatment with NE. The desensitization is also mediated by a1-receptors and intracellularly by increased [Ca2+]i and calmodulin but not by protein kinase C. The kinetics of the desensitization are similar to those of inhibition of protein synthesis or transcription and the desensitization is associated with a comparable decrease in the number of a1-receptors.

    Mitochondrial Ca2+ levels ([Ca2+]m) were monitored within brown adipocytes with mitochondrially targeted aequorin. [Ca2+]m was not a simple reflection of [Ca2+]i; rather, evidence is presented for the existence of a b-adrenergic, cAMP-mediated signal that augments the [Ca2+]m/[Ca2+]i ratio. This signal causes the mitochondria to sequester Ca2+ even in the absence of increased cytosolic levels. Inhibition of mitochondrial Ca2+ uptake augments the cytosolic responses. Mitochondria may thus play an important role even in cytosolic Ca2+homeostasis in brown adipocytes.

    Chronic treatment of brown adipocytes with NE resulted in marked alterations of cytosolic Ca2+ handling, but the mitochondria retained their ability to sequester Ca2+during adrenergic stimulation, i.e. under conditions when UCP1 should be active.

    The effects of an increase in [Ca2+]i involve activation of a cAMP phosphodiesterase, and the presence of this component explains the unusual kinetic characteristics of norepinephrine-induced cAMP accumulation. [Ca2+]i is also involved in the regulation of gene expression: increased [Ca2+]i interacts synergistically with cAMP in the control of c-fos expression which may be of significance for regulation of cell proliferation and differentiation.

    It was concluded that Ca2+ is a primary regulator of physiological functions in brown adipocytes. The Ca2+ transport systems in brown adipocytes are involved in the regulation of intracellular and intraorganellar Ca2+. Changes of the free cytosolic Ca2+ concentration by hormone stimulation induces the activation of many physiological processes.

  • 1168413.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Biosensing using transistors with silicon nanowires/nanoribbons2011Conference paper (Refereed)
  • 1168414.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Interaction of silicides with dopants2009Conference paper (Refereed)
  • 1168415.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Myth and facts in the formation of ultrathin Ni-Pt silicide films2011In: Invited talk at 15th European Workshop on Materials for Advanced Metallization 2011 (MAM 2011) and Intl. Interconnect Technol. Conf. (IITC),Dresden, Germany, March 6-9, 2011, 2011Conference paper (Refereed)
    Abstract [en]

    This talk will focus on recent advancements in the formation of ultrathin Ni1-xPtx silicide films targeting CMOS technology nodes beyond 22 nm where silicide films much thinner than 10 nm are required according to the technology roadmap.  The past experience in using metal silicides for various generations of CMOS technology indicates that control of silicide formation in the sub-10 nm regime is a foremost urgent issue especially for devices fabricated on UTB/ETB-SOI substrates or with nanowire-Fins.  Our recent results show that both initial metal thickness and Pt fraction in the as-deposited Ni1-xPtx films are critical parameters determining the resultant silicide films in terms of phase formation, film thickness, specific resistivity, interfacial morphology and morphological stability.  The talk will end with the presentation of a novel process for a controllable formation of Ni1-xPtx silicide films below 8 nm in thickness.

  • 1168416.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Myth and facts of ultrathin metal silicide films formed on Si(100)2012In: China Semiconductor Technology International Conference (CSTIC) 2012, 2012Conference paper (Refereed)
    Abstract [en]

    This talk will focus on recent advancements in the formation of ultrathin Ni1-xPtx silicide films targeting CMOS technology nodes beyond 22 nm where silicide films much thinner than 10 nm are required according to the technology roadmap.  The past experience in using metal silicides for various generations of CMOS technology indicates that control of silicide formation in the sub-10 nm regime is a foremost urgent issue especially for devices fabricated on UTB/ETB-SOI substrates or with nanowire-Fins.  Our recent results show that both initial metal thickness and Pt fraction in the as-deposited Ni1-xPtx films are critical parameters determining the resultant silicide films in terms of phase formation, film thickness, specific resistivity, interfacial morphology and morphological stability.  The phenomenon is discussed with a particular mention of thermodynamic effects;  Surface energy plays an increasingly important role for thinner films with an increasing surface to volume ratio.  To illustrate the critical importance of the entropy of mixing in the formation of ternary silicide alloy films, our recent results on silicide formation and subsequent morphological stability with ultrathin Co1-xNix films are presented and discussed as well.  The talk will end with the presentation of a novel and economical process for a controllable formation of Ni1-xPtx silicide films below 8 nm in thickness, as well as its implications in advanced CMOS technology. 

  • 1168417.
    Zhang, Shi-Li
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Nickel-based contact metallization for SiGe MOSFETs: progress and challenges2003In: Microelectronic Engineering, ISSN 0167-9317, E-ISSN 1873-5568, Vol. 70, no 04-feb, p. 174-185Article in journal (Refereed)
    Abstract [en]

    The Ni-based self-aligned silicide process has attracted a rapidly growing interest for contact metallization in Si technology, as the device dimensions are scaled down into the sub-100 nm regime. Incorporation of Ge in the electrodes of a MOSFET, i.e. gate and source/drain, in order to further enhance device performance, has made the study of Ni-Si1-xGex interactions a scientifically and technologically important issue. Among the different germanosilicides of Ni, NiSi1-uGeu (i.e. mono-germanosilicide, with u possibly different from x in the Si1 -xGex) is the most desirable phase due to its low specific resistivity of 12-25 muOmegacm. The focus of the present work is placed on issues concerning the phase and morphology stability of NiSi1-uGeu on single-crystal and polycrystalline Si1-xGex substrates. The related experimental data from our recent work are analysed with reference to two classics on the formation of silicides by d'Heurle [J. Mater. Res. 3 (1988) 167] and by d'Heurle and Gas [J. Mater. Res. 1 (1986) 205]. Influences of C and Pt on the stability of NiSi1-uGeu are also covered. The electrical properties of the NiSi1-uGeu-Si1-xGex contact are discussed referring to our latest experimental results.

  • 1168418.
    Zhang, Shi-Li
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    The reaction of Ni with Si-Ge: An overview and some new considerations2005In: Proc. Electrochem. Soc., 2005, p. 597-611Conference paper (Refereed)
    Abstract [en]

    The reactive phase formation upon annealing Ni films deposited on Si-Ge alloy substrates has become an attractive research subject as a result of two parallel rapid developments in Si technology: (1) the down-scaling of CMOS technology to the sub-50 nm regime and (2) the incorporation of Ge in standard Si-MOSFET for performance enhancement. Recent publications concern the phase formation and stability of the formed Ni(Si-Ge)p (p=0.5, 1 or 2), microstructure and morphological instability of the grown Ni(Si-Ge) (p=1) layers, and electrical behavior of the transition region at the Ni(Si-Ge)/Si-Ge interface. In the present work, those aspects are further discussed. Assumptions and simplifications were made when calculating the approximate phase diagram for the Ni-Si-Ge ternary system. Several of those assumptions are discussed in greater details in this work. An attempt to estimate the solid solubility of Ge in NiSi2 is presented, which yields a value less than 1 at.%. The role of Ge in the morphological instability at the interfacial region between Ni(Si-Ge)p and Si-Ge is discussed in the light of recently published experimental data. Incorporating further elements such as Pt or C could lead to improved interface morphology. The potential consequences of such additions include increased process complexity and different kinds of instabilities. Lateral encroachment of Ni(Si-Ge)p in contact windows has been observed, which is caused by the fast Ni diffusion (faster than Si and Ge) during the growth of the monosilicide or germanosilicide. These effects can be catastrophic to the unaware and careful process design is needed to control the lateral growth. The reported large thermal expansion coefficients of NiSi could be the cause for reliability problems such as void formation between the formed NiSi and the Si channel. The fiber texture development observed in the grown NiSi1-xGex in combination with the anisotropy of the thermal expansion coefficients of NiSi are discussed as a likely engineering approach to minimizing void formation.

  • 1168419.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Ultrathin Ni1-xPtx Films as Electrical Contact in CMOS Devices2012In: Silicon Compatible Materials, Processes, and Technologies for Advanced Integrated Circuits and Emerging Applications 2 / [ed] Roozeboom, F; Kakushima, K; Iwai, H; Timans, PJ; Narayanan, V; Kwong, DL; Gusev, EP, 2012, p. 15-22Conference paper (Refereed)
    Abstract [en]

    Metal silicide films are likely to continue their role as electrical contact in CMOS devices beyond the 22-nm technology node.  For such devices, the thickness of the silicide films is projected by the technology roadmap to be below 10 nm.  Nickel-based silicides, especially the monosilicide Ni1-xPtxSi obtained by alloying Ni with a certain fraction of Pt, are among the most competitive choices for this application.  For this specific family of silicides, the latest experimental investigations show that upon identical formation conditions (temperature and time), the phase, crystallinity, and thickness of the resultant silicide films sensitively depend on the thickness and composition of the deposited Ni1-xPtx films.  A proper understanding of these experimental observations is of vital implications in guiding technical designs for the formation of ultrathin Ni1-xPtx silicide films with desired properties. 

    This overview will start with a novel process that has recently been developed for a precise control of thickness and composition of the resultant ultrathin Ni1-xPtx silicide films below 10 nm thickness.  A unique advantage of this process, in comparison with a range of other attempts such as precise metal thickness control and two-step annealing, is the silicide formation independent of the geometrical dimension of contact areas.  In combination with dopant segregation technique by ion implantation of appropriate dopants into the formed ultrathin silicide films followed by a drive-in annealing at moderate temperatures, it is further shown that the Schottky barrier heights (SBHs) of the contact between such ultrathin silicide films and the Si substrate can be effectively modified.  The modification is so substantial that the effective SBHs can be decreased from 0.3-0.8 eV to below 0.2 eV for both conduction polarities without much effort.  This novel process is under further development for applications in devices of non-planar surfaces and fabricated on insulating substrates.

  • 1168420.
    Zhang, Shi-Li
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Understanding solid-state interactions: Ultrathin Ni1-xPtx silicide films formed on Si(100)2012In: Materials Research Society Spring Meeting 2012, San Francisco, April 9-13, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    This talk will focus on recent advancements in the formation of ultrathin Ni1-xPtx silicide films targeting CMOS technology nodes beyond 22 nm where silicide films much thinner than 10 nm are required according to the technology roadmap.  The past experience in using metal silicides for various generations of CMOS technology indicates that control of the silicide formation in the sub-10 nm regime is a foremost urgent issue especially for devices fabricated on UTB/ETB-SOI (ultrathin-body/extremely-thin-body silicon-on-insulator) substrates or with nanowire-like Fins.  Our recent results show that both initial metal thickness and Pt fraction in the as-deposited Ni1-xPtx films are critical parameters determining the resultant silicide films in terms of phase formation, film thickness, specific resistivity, interfacial morphology and morphological stability at elevated temperatures.  The phenomenon is discussed with a particular mention of thermodynamic effects.  Surface energy plays an increasingly important role for thinner films with an increasing surface to volume ratio.  To illustrate the critical importance of the entropy of mixing in the formation of ternary Ni-Pt-Si silicide alloy films, our recent results on silicide formation and subsequent morphological stability starting with ultrathin Co1-xNix films are presented and discussed as well.  The talk will end with the presentation of a novel and economical process for a controllable formation of Ni1-xPtx silicide films below 8 nm in thickness, as well as its implications in advanced CMOS technology. 

  • 1168421.
    Zhang, Shi-Li
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    d'Heurle, F. M.
    Influence of molybdenum on the formation of C54TiSi(2): Template phenomenon versus grain-size effect2000In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 76, no 14, p. 1831-1833Article in journal (Refereed)
    Abstract [en]

    Experimental results are presented for the formation of TiSi2 in the presence of an ultrathin Mo layer deposited either at the interface between Ti and Si or on top of Ti/Si. The formation of C54 TiSi2 is clearly shown to be enhanced with a surface Mo layer, although the effect is less pronounced as compared to the use of an interposed Mo layer. The results can be accounted for with a template mechanism where the formation of C40 (Mo, Ti)Si-2 is crucial for the epitaxial growth of C54 TiSi2 atop. Possible grain-size effects on the formation of C54 TiSi2 are also discussed.

  • 1168422.
    Zhang, Shi-Li
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Hu, X. H.
    Li, H. D.
    Shi, Z. J.
    Yue, K. T.
    Zi, J.
    Gu, Z. N.
    Wu, X. H.
    Lian, Z. L.
    Zhan, Y.
    Huang, F. M.
    Zhou, L. X.
    Zhang, Y. G.
    Iijima, S.
    Abnormal anti-Stokes Raman scattering of carbon nanotubes2002In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 66, no 3Article in journal (Refereed)
    Abstract [en]

    Abnormal anti-Stokes Raman scattering (AASR) was unambiguously observed in carbon nanotubes (CNT's). In contrast to traditional Raman scattering theory, the absolute value of the Raman frequency of the anti-Stokes peak is not the same as that of the corresponding Stokes peak. It was demonstrated that AASR scattering originates from the unique nanoscale cylindrical structure of CNT's that can be considered naturally as a graphite structure with an intrinsic defect from its rolling. The double-resonance Raman scattering theory was applied to interpret the scattering mechanism of the AASR phenomenon successfully and quantitatively.

  • 1168423.
    Zhang, Shi-Li
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Smith, U.
    Self-aligned silicides for ohmic contacts in complementary metal-oxide-semiconductor technology: TiSi2, CoSi2 and NiSi2004In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 22, no 4, p. 1361-1370Article in journal (Refereed)
    Abstract [en]

    Metal silicides continue to play an indispensable role during the remarkable development of microelectronics. Along with several other technological innovations, the implementation of the self-aligned silicide technology paved the way for a rapid and successful miniaturization of device dimensions for metal-oxide-semiconductor field-effect transistors (MOSFETs) in pace with the Moore's law. The use of silicides has also evolved from creating reliable contacts for diodes, to generating high-conductivity current paths for local wiring, and lately to forming low-resistivity electrical contacts for MOSFETs. With respect to the choice of silicides for complementary metal-oxide- semiconductor (CMOS) technology, a convergence has become clear with the self-alignment technology using only a limited number of silicides, namely TiSi2, CoSi2, and NiSi. The present work discusses the advantages and limitations of TiSi2, CoSi2, and NiSi using the development trend of CMOS technology as a measure. Specifically, the reactive diffusion and phase formation of these silicides in the three terminals of a MOSFET, i.e., gate, source, and drain, are analyzed. This work ends with a brief discussion about future trends of metal silicides in micro/nanoelectronics with reference to potential material aspects and device structures outlined in the International Technology Roadmap for Semiconductors.

  • 1168424.
    Zhang, Shi-Li
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Zhang, Z.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Metal silicides in advanced complementary metal-oxide-semiconductor (CMOS) technology2014In: Metallic Films for Electronic, Optical and Magnetic Applications: Structure, Processing and Properties, Woodhead Publishing Limited, 2014, no 40, p. 244-301Chapter in book (Refereed)
    Abstract [en]

    Metal silicides have become a basic building block in silicon (Si) metal-oxide-semiconductor field-effect transistors (MOSFETs). During the past three decades, several different silicides have served various generations of complementary metal-oxide-semiconductor (CMOS) technology primarily as a low-resistivity solution to parasitic resistances in the three terminals of a MOSFET. The latest developments of CMOS technology have led to a converged utilisation of Ni-silicides for metallisation of the source and drain regions of transistors with 45 and 32 nm channel lengths. These developments have followed a set of basic requirements and fundamental rules for the silicide formation and growth. This chapter provides an overview of the technological developments of contact metallisation in advanced CMOS technology and attempts to project into the near future about the role of metal silicides in extremely scaled CMOS devices with non-planar device architectures. Fundamental aspects critical to past developments and to future projections will be discussed.

  • 1168425.
    Zhang, Shi-Li
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Zhang, Z. B.
    Zhu, D. Z.
    Xu, H. J.
    Differences between interfacial and surface molybdenum in the formation Of TiSi22001In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 89, no 3, p. 1641-1646Article in journal (Refereed)
    Abstract [en]

    Backscattering and diffraction results are presented for the effects of an interfacial or a surface Mo layer on the formation of Ti-silicides during solid-state interaction between Ti films and Si substrates. It is shown that the interfacial and surface Mo are fundamentally different in their involvement in the Ti-silicide formation. The interfacial Mo induces the formation of C40 (Mo,Ti)Si-2 at the interface adjacent to the Si substrate already after annealing at 550 degreesC, in agreement with our previous results. Hence, the desired C54 TiSi2 can grow directly on top of the C40 (Mo,Ti)Si-2 at relatively low temperatures as a result of the template effect. The surface Mo is, however, found in a metal-rich silicide presumably (Mo,Ti)(5)Si-3 at 550-600 degreesC, which eventually converts to (Mo,Ti)Si-2 upon annealing at higher temperatures. Underneath this metal-rich silicide lies a fully developed C49 TiSi2 layer. Consequently, the formation of C54 TiSi2 in the presence of surface Mo follows the usual path of the C49-C54 phase transition. This important difference in the participation of Mo in the silicide formation spreads doubts about the validity of using interfacial Mo versus surface Mo to study the dominant mechanism(s) responsible for the enhanced formation of C54 TiSi2.

  • 1168426. Zhang, Shili
    et al.
    Zhang, Zhen
    Metal Silicides in Advanced CMOS Technology2014In: Metallic films: structure, processing and properties / [ed] Katayun Barmak and Kevin Coffey, UK: Woodhead Publishing Limited, 2014Chapter in book (Other academic)
  • 1168427.
    Zhang, Shi-Li
    et al.
    KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
    Zou, Qichao
    Wu, Limin
    Preparation and characterization of polyurethane hybrids from reactive polyhedral oligomeric silsesquioxanes2006In: Macromolecular materials and engineering (Print), ISSN 1438-7492, E-ISSN 1439-2054, Vol. 291, no 7, p. 895-901Article in journal (Refereed)
    Abstract [en]

    Hybrid polyester resins containing polyhedral oligomeric silsesquioxanes (POSS), and their polyurethanes were prepared using reactive POSS as a substitution for partial diol monomer. They were investigated by FT-IR, rheometry, dynamic mechanical analysis, wide-angle X-ray diffraction contact-angle measurement, atomic force microscopy, and thermogravimetric analysis, respectively. The results showed that the hybrid polyester-POSS resins had a shear thinning behaviour and the more the POSS was embedded, the stronger the shear thinning behaviour, and the higher the viscosity. Incorporation of POSS could increase the glass transition temperature and thermal stability and decrease the surface free energy of the polyurethanes. When the POSS content was relatively high, the POSS molecules in hybrid polyurethane-POSS had a strong self-assembling ability to form nanocrystalline domains.

  • 1168428.
    Zhang, Shi-Li
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Östling, Mikael
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Metal silicides in CMOS technology: Past, present, and future trends2003In: Critical reviews in solid state and materials sciences, ISSN 1040-8436, E-ISSN 1547-6561, Vol. 28, no 1, p. 1-129Article, review/survey (Refereed)
    Abstract [en]

    Metal silicides have played an indispensable role in the rapid developments of microelectronics since PtSi was first used to improve the rectifying characteristics of diodes in early 1960s. This work first provides a brief historical overview of the many different silicides, and, correspondingly. the different processing methodologies used in the past. With regard to the present use of silicides in CMOS technologies, a convergence becomes clear with the self-aligned technology using only a limited number of silicides, namely, TiSi2, CoSi2, and NiSi. A section on fundamental aspects is included to cover thermodynamics and kinetics, which are essential for understanding the silicide formation processes. The advantages and disadvantages of TiSi2, CoSi2, and NiSi are analyzed with the development trend of CMOS technologies as a measure. Specifically, the reactive diffusion and phase formation of these silicides in the three terminals of a metal-oxide-semiconductor device, that is, gate, source, and drain, are scrutinized. The review ends with an extended discussion about future trends of metal silicides in micro/nanoelectronics, with reference to the potential material aspects and device structures outlined in the International Technology Roadmap for Semiconductors.

  • 1168429. Zhang, Shipeng
    et al.
    Wang, Minghuai
    Ghan, Steven J.
    Ding, Aijun
    Wang, Hailong
    Zhang, Kai
    Neubauer, David
    Lohmann, Ulrike
    Ferrachat, Sylvaine
    Takeamura, Toshihiko
    Gettelman, Andrew
    Morrison, Hugh
    Lee, Yunha
    Shindell, Drew T.
    Partridge, Daniel G.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Oxford, UK.
    Stier, Philip
    Kipling, Zak
    Fu, Congbin
    On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 5, p. 2765-2783Article in journal (Refereed)
    Abstract [en]

    Aerosol-cloud interactions continue to constitute a major source of uncertainty for the estimate of climate radiative forcing. The variation of aerosol indirect effects (AIE) in climate models is investigated across different dynamical regimes, determined by monthly mean 500 hPa vertical pressure velocity (omega(500)), lower-tropospheric stability (LTS) and large-scale surface precipitation rate derived from several global climate models (GCMs), with a focus on liquid water path (LWP) response to cloud condensation nuclei (CCN) concentrations. The LWP sensitivity to aerosol perturbation within dynamic regimes is found to exhibit a large spread among these GCMs. It is in regimes of strong large-scale ascent (omega(500)aEuro-aEuro parts per thousand < aEuro-a'25 hPa day(-1)) and low clouds (stratocumulus and trade wind cumulus) where the models differ most. Shortwave aerosol indirect forcing is also found to differ significantly among different regimes. Shortwave aerosol indirect forcing in ascending regimes is close to that in subsidence regimes, which indicates that regimes with strong large-scale ascent are as important as stratocumulus regimes in studying AIE. It is further shown that shortwave aerosol indirect forcing over regions with high monthly large-scale surface precipitation rate (> 0.1 mm day(-1)) contributes the most to the total aerosol indirect forcing (from 64 to nearly 100 %). Results show that the uncertainty in AIE is even larger within specific dynamical regimes compared to the uncertainty in its global mean values, pointing to the need to reduce the uncertainty in AIE in different dynamical regimes.

  • 1168430.
    Zhang, Shouting
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Studies on the Molecular Biology of the Mouse Pneumotropic Polyomavirus2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Murine Pneumotropic Virus (MPtV), in contrast to the other MurinePolyomavirus (MPyV), appears to be non-tumourigenic in its natural host. Instead, MPtV causes acute pneumonia and can serve as a model in studies of polyomavirus-induced disease. In initial experiments, MPtV large T-antigen (LT) was expressed in a heterologous system. LT was characterized with regard to its metabolic stability and cell immortalizing activity and, after purification, to its specific DNA binding.

    The absence of permissive cell culture system for MPtV has hampered its study. We made attempts to widen the host range of the virus by modifying the regulatory and late regions of the genome. The enhancer substitution mutant (KVm1), having a transcriptional enhancer substituted with a corresponding DNA segment from MPyV, was able to replicate in mouse 3T3 cells and form virus particles that were infectious in mice. However, efficient infection of cells in vitro was not achieved with this mutant virus, possibly due to the absence of virus-specific receptors on the cells. The capsid protein substitution mutants, having capsid protein genes of MPyV, for which receptors are present on a variety of cell types, showed also no cytopathic effect, despite an enhanced viral DNA replication and assembly of virus particles.

    MPtV-DNA extracted from virus in lung tissue of infected mice had a heterogeneous enhancer segment. A majority of the DNA molecules had a structure differing from the standard-type. A 220 base-pair insertion at nucleotide position 142 with a concomitant deletion of nucleotides 143 to 148 was a prominent variation. Other genome variants showed complete or partial deletions of the insertion and surrounding sequences in the viral enhancer. In relation to the standard-type, all variant genomes showed differences in the activities of transcriptional promoters and the origin DNA replication. Analysis by DNA reassociation showed that a large number of nucleotide sequences related to the 220 base-pair insert in the MPtV genome were present in mouse and human DNA, but not in Escherichia coli DNA. Together, the data suggest that the 220 base-pair insertion is related to a transposable element of a novel type.

  • 1168431.
    Zhang, Shouting
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Ekman, Maria
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Thakur, Noopur
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Bu, Shizhong
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Davoodpour, Padideh
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Grimsby, Susanne
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Tagami, Seicchi
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Heldin, Carl-Henrik
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Medicinska och farmaceutiska vetenskapsområdet, centrumbildningar mm , Ludwig Institute for Cancer Research.
    Landström, Marene
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Genetics and Pathology.
    TGF beta 1-induced activation of ATM and p53 mediates apoptosis in a Smad7-dependent manner2006In: Cell Cycle, ISSN 1538-4101, E-ISSN 1551-4005, Vol. 5, no 23, p. 2787-2795Article in journal (Refereed)
    Abstract [en]

    ATM, a DNA-damage sensitive kinase and p53, are frequently inactivated in a variety of cancers as they together with gamma H2AX are critical guardians against DNA damage. Here, we report of a functional cross-talk between the cytokine TGF beta and p53, leading to apoptosis of epithelial cells, involving Smad7, a TGF beta target gene, p38 MAP kinase, and ATM. Using ectopic expression of p53, siRNA for Smad7, p38a(-/-) deficient cells and specific inhibitors, we show that TGF-beta induces apoptosis via ATM and p53 in epithelial cells. Intriguingly, Smad7 act as a scaffold protein to promote functional interactions between p38, ATM and p53 upon TGF beta treatment, facilitating their activation. Smad7. colocalizes with gamma H2AX in DNA damage foci and was required for proper cell cycle checkpoints to prevent genetic instability. Our data imply that Smad7 plays a crucial role upstream of ATM and p53 to protect the genome from insults evoked by extracellular stress.

  • 1168432.
    Zhang, Shouting
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Magnusson, Göran
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Cellular mobile genetic elements in the regulatory region of the pneumotropic mouse polyomavirus genome: structure and function in viral gene expression and DNA replication2003In: Journal of Virology, ISSN 0022-538X, E-ISSN 1098-5514, Vol. 77, no 6, p. 3477-3486Article in journal (Refereed)
    Abstract [en]

    DNA from the murine pneumotropic virus was extracted from virus in lung tissue of infected mice, and the regulatory region of the genome was amplified by PCR. The regulatory region of individual plasmid cloned DNA molecules appeared to have heterogeneous enhancer segments, whereas the protein-coding part of the genome had a uniform length. Nucleotide sequence analysis revealed that the majority of the DNA molecules had a structure differing from the standard type. A 220-bp insertion at nucleotide position 142 with a concomitant deletion of nucleotides 143 to 148 was prominent. There were two variants of the 220-bp insertion, differing at two nucleotide positions at one of the termini. Other DNA molecules had complete or partial deletions of these structures and surrounding sequences in the viral enhancer. However, the end of the insertion at nucleotide 142 was frequently preserved. The viral early and late promoter activity of the variant regulatory regions was tested in a luciferase reporter assay by using transfected NIH 3T3 cells. In relation to the standard-type DNA, all variants, including a G272T mutant, had much stronger late promoters. In contrast, the early promoter activity was influenced in a positive or negative direction by individual mutations. Also, the activity of the viral origin of DNA replication was affected by the sequence variation of the regulatory region, although the effects were smaller than for the late promoter. Analysis by Southern blotting and quantification using dot blots showed that approximately 103 copies of material related to the 220-bp insert in murine pneumotropic virus DNA was present in mouse and human DNA but not in Escherichia coli DNA. Moreover, analysis by PCR indicated that there were multiple copies in the mouse genome of sequences that were identical or closely related to the 220-bp viral DNA segment. These data together with the nucleotide sequence analysis suggest that the 220-bp insertion is related to a transposable element of a novel type.

  • 1168433.
    Zhang, Shouting
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Magnusson, Göran
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Kilham polyomavirus: activation of gene expression and DNA replication in mouse fibroblast cells by an enhancer substitution2001In: Journal of Virology, ISSN 0022-538X, E-ISSN 1098-5514, Vol. 75, no 21, p. 10015-10023Article in journal (Refereed)
    Abstract [en]

    The Kilham strain of polyomavirus (KV) infects vascular endothelial cells in vivo (J. E. Greenlee, Infect. Immun. 26:705-713, 1979), but no permissive cell type for growth of the virus in vitro has been identified. The failure of KV DNA to replicate in mouse fibroblast cells after transfection suggested that viral gene expression had narrow cell specificity. A KV substitution mutant having a part of the regulatory region of KV DNA replaced with a segment of the polyomavirus transcriptional enhancer was constructed. The substitution mutant was able to replicate in transfected 3T3 cells, and the newly replicated viral DNA associated with protein to form particles with the density of virions in CsCl equilibrium gradients. However, these particles were noninfectious when tested on 3T3 cells, suggesting that absorption or uptake of virus particles was defective for these cells. Analysis of early and late promoter activities by luciferase reporter gene expression showed that the enhancer substitution had a moderate positive effect on early gene expression and a large effect on the expression of the late genes. KV large T antigen inhibited the activities of both the wild-type and the substitution mutant early promoter, whereas only the mutant late promoter was activated under the same conditions. A comparison of the KV and polyomavirus large T antigens showed that they were not interchangeable in the initiation of KV and polyomavirus DNA synthesis. Furthermore, the wild-type KV origin of DNA replication was less active than the mutant structure in the presence of saturating amounts of KV large T antigen. Together, our data demonstrate several differences between the two types of large T antigen in their interactions with cellular proteins.

  • 1168434.
    Zhang, Shouting
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Magnusson, Göran
    Large T antigen from the Murine Pneumotropic Virus: expression and analysis of DNA bindingManuscript (Other academic)
  • 1168435.
    Zhang, Shuai
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Benchmarking Performance of Web Service Operations2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Web services are often used for retrieving data from servers providing information of different kinds. A data providing web service operation returns collections of objects for a given set of arguments without any side effects. In this project a web service benchmark (WSBENCH) is developed to simulate the performance of web service calls. Web service operations are specified as SQL statements. The function generator of WSBENCH converts user specified SQL queries into functions and automatically generates a web service. WSBENCH can automatically both generate and deploy web the service operations for exported functions. Furthermore WSBENCH supports controlled experiments, since users can control the characteristics of web service operations such as scalability of data and delay time. The database used in this project is generated by the Berlin Benchmark database generator.

    A WSBENCH demo is built to demonstrate the functionality. The demo is implemented as a JavaScript program acting as a SOAP client, directly calls WSBENCH services from a web browser. Users can make a web service request by simply providing the web service operation’s name and parameter values list as the input. It makes the WSBENCH very simple to the use.

  • 1168436.
    Zhang, Shuai
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Investigating and Enhancing Performance of Multiple Antenna Systems in Compact MIMO/Diversity Terminals2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Today, owners of small communicating device are interested in transmitting or receiving various multimedia data. By increasing the number of antennas at the transmitter and/or the receiver side of the wireless link, the diversity/Multiple-Input Multiple-Output (MIMO) techniques can increase wireless channel capacity without the need for additional power or spectrum in rich scattering environments. However, due to the limited space of small mobile devices, the correlation coefficients between MIMO antenna elements are very high and the total efficiencies of MIMO elements degrade severely. Furthermore, the human body causes high losses on electromagnetic wave. During the applications, the presence of users may result in the significant reduction of the antenna total efficiencies and highly affects the correlations of MIMO antenna systems. The aims of this thesis are to investigate and enhance the MIMO/diversity performance of multiple antenna systems in the free space and the presence of users.

    The background and theory of multiple antenna systems are introduced briefly first. Several figures of merits are provided and discussed to evaluate the multiple antenna systems. The decoupling techniques are investigated in the multiple antenna systems operating at the higher frequencies (above 1.7 GHz) and with high radiation efficiency. The single, dual and wide band isolation enhancements are realized through the half-wavelength decoupling slot, quarter-wavelength decoupling slot with T-shaped impedance transformer, tree-like parasitic element with multiple resonances, as well as the different polarizations and radiation patterns of multiple antennas.

    In the lower bands (lower than 960 MHz), due to the low radiation efficiency and strong chassis mode, the work mainly focused on how to directly reduce the correlations and enlarge the total efficiency. A new mode of mutual scattering mode is introduced. By increasing the Q factors, the radiation patterns of multiple antennas are separated automatically to reduce the correlations. With the inter-element distance larger than a certain distance, a higher Q factor also improved the total efficiency apart from the low correlation. A wideband LTE MIMO antenna with multiple resonances is proposed in mobile terminals. The high Q factors required for the low correlation and high efficiencies in mutual scattering mode is reduced with another mode of diagonal antenna-chassis mode. Hence, the bandwidth of wideband LTE MIMO antenna with multiple resonances mentioned above can be further enlarged while maintaining the good MIMO/diversity performance.

    The user effects are studied in different MIMO antenna types, chassis lengths, frequencies, port phases and operating modes. Utilizing these usefully information, an adaptive quad-element MAS has been proposed to reduce the user effects and the some geranial rules not limited to the designed MAS have also been given.

  • 1168437.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Alayón Glazunov, Andrés
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Ying, Zhinong
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Reduction of the envelope correlation coefficient with improved total efficiency for mobile LTE MIMO antenna arrays: Mutual scattering mode2013In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 61, no 6, p. 3280-3291Article in journal (Refereed)
    Abstract [en]

    A mutual scattering mode is introduced in this paper. Utilizing this mode, the correlation of a lossy long-term evolution (LTE) multiple-input and multiple-output (MIMO) antenna array can be reduced efficiently, even down to zero, by increasing the Q factors of the MIMO antenna elements. In practice, the Q factors can be straight forwardly tuned through different input impedance matching. The zero correlation occurs at a Q factor higher than that resulting from the conjugate input impedance matching. On one hand, if the inter-element distance is larger than a certain distance (what we denominate as the Critical Distance), the total efficiency can also be improved in addition to reducing the correlation. On the other hand, when the inter-element distance is less than the critical distance, a reference MIMO antenna with high correlation and high total efficiency is obtained. This antenna can well be proposed for over-the-air (OTA) measurement applications. The introduced scattering mode is investigated for dual monopoles on a large lossy ground plane and for various mobile terminal MIMO antenna designs. A wideband MIMO antenna, with multiple resonances, covering the band 746-870 MHz is proposed with the envelope correlation coefficient and total efficiency less than 0.5 and higher than 50% (-3 dB), respectively. Measurements and simulations agree well for all the fabricated prototypes. The envelope correlations and the multiplexing efficiencies of the prototypes are also investigated in propagation channels with Gaussian distributed angle of arrivals.

  • 1168438.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Glazunov, Andrés Alayon
    Ying, Zhinong
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Reduction of the Envelope Correlation Chofficient with Improved Total Efficiency for Mobile LTE MIMO Antennas Arroys: Mutual Scattering ModeArticle in journal (Other academic)
  • 1168439.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Khan, Salman Naeem
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Reducing Mutual Coupling for an Extremely Closely-Packed Tunable Dual-Element PIFA Array Through a Resonant Slot Antenna Formed In-Between2010In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 58, no 8, p. 2771-2776Article in journal (Refereed)
    Abstract [en]

    An efficient mutual coupling reduction method is introduced for an extremely closely packed tunable dual-element planar inverted-F antenna (PIFA) array. High isolation can be achieved through a lambda(0)/2 folded slot antenna formed by a slot on the ground plane and the neighboring edges of the two PIFAs. Direct coupling is blocked by the slot antenna through radiating the coupling power into free space. A measured isolation of more than 36.5 dB can be achieved between the two parallel individual-element PIFAs operating at 2.4 GHz WLAN band with an inter-PIFA spacing of less than 0.063 lambda(0) (center to center) or 0.0147 lambda(0) (edge to edge). Since there is only a narrow slot antenna formed between the PIFAs in the present method, the distance can be further reduced to less than 0.0016 lambda(0) (edge to edge) with the maximal isolation of better than 40 dB. Both measured and simulation results show the effectiveness of the present mutual coupling reduction method.

  • 1168440.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Lau, B. K.
    Sunesson, A.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Compact UWB MIMO antenna for USB dongles with angle and polarization diversity2012In: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest), 2012, p. 778-781Conference paper (Refereed)
    Abstract [en]

    A compact dual-element antenna suitable for ultrawideband (UWB) MIMO operation is proposed in this work. The size of the antenna is 25 mm by 40 mm and it covers the lower UWB band of 3.15-5.15 GHz. Apart from the inherent wideband isolation obtained through the different angle and polarization characteristics in the radiation patterns of the individual elements, the gap between the two antenna elements is also utilized to enhance both the isolation and impedance bandwidths. Simulation and experimental results reveal that, within the band of interest, the achieved isolation is over 20 dB and the envelope correlation of the radiation patterns is below 0.1.

  • 1168441.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Lau, Buon Kiong
    Lund University.
    Sunesson, Anders
    Lund University.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Closely Located Dual PIFAs with T-Slot Induced High Isolation for MIMO Terminals2011In: 2011 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (APSURSI), 2011, p. 2205-2207Conference paper (Refereed)
    Abstract [en]

    This paper presents an efficient technique to enhance the isolation between two closely spaced PIFAs for MIMO mobile terminals. The proposed decoupling method is based on a T-shape slot impedance transformer and it enables an inter-PIFA spacing of 1 mm to be achieved. The 10 dB impedance bandwidth and 20 dB isolation bandwidth cover the 2.4 GHz WLAN band (2.4-2.48 GHz), with a maximum isolation of 44 dB. The efficiency, gain, radiation patterns of the two-PIFA prototype are also verified in measurements.

  • 1168442.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Lau, Buon Kiong
    Sunesson, Anders
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Closely-Packed UWB MIMO/Diversity Antenna With Different Patterns and Polarizations for USB Dongle Applications2012In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 60, no 9, p. 4372-4380Article in journal (Refereed)
    Abstract [en]

    A closely-packed ultrawideband (UWB) multiple-input multiple-output (MIMO)/diversity antenna (of two elements) with a size of 25 mm by 40 mm is proposed for USB dongle applications. Wideband isolation can be achieved through the different patterns and polarizations of the two antenna elements. Moreover, the slot that is formed between the monopole and the ground plane of the half slot antenna is conveniently used to further enhance the isolation at the lower frequencies and to provide an additional resonance at one antenna element in order to increase its bandwidth. The underlying mechanisms of the antenna's wide impedance bandwidth and low mutual coupling are analyzed in detail. Based on the measurement results, the proposed antenna can cover the lower UWB band of 3.1-5.15 GHz, and within the required band, the isolation exceeds 26 dB. The gains and total efficiencies of the two antenna elements are also measured. Furthermore, a chassis mode can be excited when a physical connection is required between the ground planes of the two antenna elements. Without affecting the performance of the half slot element, the monopole can now cover the band of 1.78-3 GHz, apart from the UWB band. The proposed antenna structure is found to provide good MIMO/diversity performance, with very low envelope correlation of less than 0.1 across the UWB band.

  • 1168443.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Lau, Buon Kiong
    Tan, Yi
    Ying, Zhinong
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Mutual Coupling Reduction of Two PIFAs With a T-Shape Slot Impedance Transformer for MIMO Mobile Terminals2012In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 60, no 3, p. 1521-1531Article in journal (Refereed)
    Abstract [en]

    An efficient technique is introduced to reduce mutual coupling between two closely spaced PIFAs for MIMO mobile terminals. The proposed mutual coupling reduction method is based on a T-shape slot impedance transformer and can be applied to both single-band and dual-band PIFAs. For the proposed single-band dual PIFAs, the 10 dB impedance bandwidth covers the 2.4 GHz WLAN band (2.4-2.48 GHz), and within the WLAN band an isolation of over 20 dB is achieved. Moreover, the dual-band version covers both the WLAN band and the WiMAX band of 3.4-3.6 GHz, with isolations of over 19.2 dB and 22.8 dB, respectively. The efficiency, gain and radiation patterns of the two-PIFA prototypes are verified in measurements. Due to very low pattern correlation and very good matching and isolation characteristics, the capacity performances are mainly limited by radiation efficiency. The single-band and dual-band PIFAs are also studied with respect to their locations on the ground plane. An eight-fold increase in the bandwidth of one PIFA is achieved, when the single-band PIFAs are positioned at one corner of the ground plane, with the bandwidth of the other PIFA and the good isolation unchanged.

  • 1168444.
    Zhang, Shuai
    et al.
    West Pomeranian Univ Technol, Poland.
    Shi, Xiaoze
    West Pomeranian Univ Technol, Poland.
    Chen, Xuecheng
    West Pomeranian Univ Technol, Poland; Chinese Acad Sci, Peoples R China.
    Zhang, Dengsong
    Shanghai Univ, Peoples R China.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Zhang, Zhibin
    Uppsala Univ, Sweden.
    Chu, Paul K.
    City Univ Hong Kong, Peoples R China; City Univ Hong Kong, Peoples R China.
    Tang, Tao
    Chinese Acad Sci, Peoples R China.
    Mijowska, Ewa
    West Pomeranian Univ Technol, Poland.
    Large-Scale and Low-Cost Motivation of Nitrogen-Doped Commercial Activated Carbon for High-Energy-Density Supercapacitor2019In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 6, p. 4234-4243Article in journal (Refereed)
    Abstract [en]

    The growing requirement for high-performance energy-storage devices has spurred the development of supercapacitors, but the low energy density remains a technical hurdle. In this work, porous nitrogen-doped activated carbon (NAC) is prepared on a large scale from commercial activated carbon (AC) and inexpensive chemicals by a one-step method. The NAC material with 3.1 wt % nitrogen has a high specific surface area of 1186 m(2) g(-1) and shows a specific capacitance of 427 F g(-1) in a symmetric cell with an aqueous electrolyte. 98.2% of the capacity is reserved after 20 000 cycles at 20 A g(-1). The energy densities of the NAC are 17.2 and 87.8 Wh kg(-1) in acidic and organic electrolytes, respectively. Moreover, this simple process is readily scalable to address commercial demand and can be extended to the motivation of a variety of carbon based materials with poor capacitances.

  • 1168445.
    Zhang, Shuai
    et al.
    West Pomeranian Univ Technol, Fac Chem Technol & Engn, Nanomat Physicochem Dept, Piastow Ave 42, PL-71065 Szczecin, Poland.
    Shi, Xiaoze
    West Pomeranian Univ Technol, Fac Chem Technol & Engn, Nanomat Physicochem Dept, Piastow Ave 42, PL-71065 Szczecin, Poland.
    Chen, Xuecheng
    West Pomeranian Univ Technol, Fac Chem Technol & Engn, Nanomat Physicochem Dept, Piastow Ave 42, PL-71065 Szczecin, Poland;Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Jilin, Peoples R China.
    Zhang, Dengsong
    Shanghai Univ, Res Ctr Nano Sci & Technol, 99 Shangda Rd, Shanghai 200444, Peoples R China.
    Liu, Xianjie
    Linkoping Univ, Dept Phys Chem & Biol, SE-58183 Linkoping, Sweden.
    Zhang, Zhibin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Chu, Paul K.
    City Univ Hong Kong, Dept Phys, Kowloon, Tat Chee Ave, Hong Kong, Peoples R China;City Univ Hong Kong, Dept Mat Sci & Engn, Kowloon, Tat Chee Ave, Hong Kong, Peoples R China.
    Tang, Tao
    Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Polymer Phys & Chem, Changchun 130022, Jilin, Peoples R China.
    Mijowska, Ewa
    West Pomeranian Univ Technol, Fac Chem Technol & Engn, Nanomat Physicochem Dept, Piastow Ave 42, PL-71065 Szczecin, Poland.
    Large-Scale and Low-Cost Motivation of Nitrogen-Doped Commercial Activated Carbon for High-Energy-Density Supercapacitor2019In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 6, p. 4234-4243Article in journal (Refereed)
    Abstract [en]

    The growing requirement for high-performance energy-storage devices has spurred the development of supercapacitors, but the low energy density remains a technical hurdle. In this work, porous nitrogen-doped activated carbon (NAC) is prepared on a large scale from commercial activated carbon (AC) and inexpensive chemicals by a one-step method. The NAC material with 3.1 wt % nitrogen has a high specific surface area of 1186 m(2) g(-1) and shows a specific capacitance of 427 F g(-1) in a symmetric cell with an aqueous electrolyte. 98.2% of the capacity is reserved after 20 000 cycles at 20 A g(-1). The energy densities of the NAC are 17.2 and 87.8 Wh kg(-1) in acidic and organic electrolytes, respectively. Moreover, this simple process is readily scalable to address commercial demand and can be extended to the motivation of a variety of carbon based materials with poor capacitances.

  • 1168446.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Ying, Z.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Mutual scattering mode for LTE MIMO antennas and its application to correlation reduction (invited)2012In: Antennas and Propagation (APCAP), 2012 IEEE Asia-Pacific Conference on, IEEE , 2012, p. 13-14Conference paper (Refereed)
    Abstract [en]

    A - mutual scattering mode -is introduced in this paper as a novel method to reduce the correlation for the LTE MIMO antenna arrays. This mode is mainly based on the increase of the Q factor for the closely-positioned MIMO antenna elements. With the increased Q factor, each element becomes a scatter for the other elements. Consequently, without adding any structure in the MIMO system, the radiation patterns will be separated to achieve a low correlation (even close to zero) in LTE 700 MHz bands. In practice, this high Q factor is realized through better impedance matching, which makes this mode quite easy to excite. When the effective MIMO element distance is larger than a certain value, better matching (higher Q factor) can not only reduce the correlation but also improve the efficiency (even though the mutual coupling becomes stronger).

  • 1168447.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Ying, Zhinong
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Diagonal Chassis Mode for Mobile Handset LTE MIMO Antennas and Its Application to Correlation Reduction2012In: 2012 IEEE International Workshop On Electromagnetics: Applications And Student Innovation Competition (IWEM) / [ed] Tang, X; Xiao, S, IEEE , 2012, p. 3022-Conference paper (Refereed)
    Abstract [en]

    A new kind of chassis mode, namely, Diagonal Chassis Mode, is introduced in this paper. It can be easily excited for PIFAs by selecting a proper shorting point on the ground plane. Through this mode the correlation coefficient between MIMO PIFAs operating at LTE 700 MHz bands can be reduced effectively with the improvement of total efficiency and impedance bandwidth.

  • 1168448.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Ying, Zhinong
    Xiong, Jiang
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Ultrawideband MIMO/Diversity Antennas With a Tree-Like Structure to Enhance Wideband Isolation2009In: IEEE Antennas and Wireless Propagation Letters, ISSN 1536-1225, E-ISSN 1548-5757, Vol. 8, p. 1279-1282Article in journal (Refereed)
    Abstract [en]

    A compact printed ultrawideband (UWB) multiple-input-multiple- output (MIMO)/diversity antenna system (of two elements) with a size of 35 40 mm operating at a frequency range of 3.1-10.6 GHz is proposed. The wideband isolation can be achieved through a tree-like structure on the ground plane. The effectiveness of the tree-like structure is analyzed. Measured S-parameters show that the isolation is better than 16 dB (20 dB in most of the band) across the UWB of 3.1-10.6 GHz. The radiation patterns, gain, and envelope correlation coefficient are also measured. The proposed antenna is suitable for some portable MIMO/diversity applications.

  • 1168449.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Ying, Zhinong
    Zhao, Kun
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Diagonal Antenna-Chassis Mode and Its Application for Wideband LTE MIMO Antennas in Mobile HandsetsArticle in journal (Other academic)
  • 1168450.
    Zhang, Shuai
    et al.
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Zetterberg, Per
    KTH, School of Electrical Engineering (EES), Signal Processing.
    He, Sailing
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Printed MIMO antenna system of four closely-spaced elements with large bandwidth and high isolation2010In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 46, no 15, p. 1052-1053Article in journal (Refereed)
    Abstract [en]

    A compact wideband printed MIMO antenna system (of four elements) with high isolation is presented. The proposed MIMO antenna system with an overall lateral size of only 0.43 lambda x 0.43 lambda can offer 22.8% bandwidth (1.63-2.05 GHz) and isolation of better than 24 dB. The measured gain is larger than 2.72 dBi over the whole band, and the calculated envelope correlation coefficient is better than 0.01. The radiation patterns and MIMO channel capacity are also measured.

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