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  • 1167801.
    Zhang, Wenhui
    et al.
    Huazhong Univ Sci & Technol, Sch Comp Sci & Technol, Wuhan Natl Lab Optoelect, Key Lab Informat Storage Syst,Minist Educ, Wuhan 430074, Hubei, Peoples R China..
    Cao, Qiang
    Huazhong Univ Sci & Technol, Sch Comp Sci & Technol, Wuhan Natl Lab Optoelect, Key Lab Informat Storage Syst,Minist Educ, Wuhan 430074, Hubei, Peoples R China..
    Lu, Zhonghai
    KTH, School of Electrical Engineering and Computer Science (EECS), Electronics.
    Bit-Flipping Schemes Upon MLC Flash: Investigation, Implementation, and Evaluation2019In: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, ISSN 0278-0070, E-ISSN 1937-4151, Vol. 38, no 4, p. 780-784Article in journal (Refereed)
    Abstract [en]

    Multilevel cell (MLC) stales with lower threshold voltage endure less cell damage, lower retention error, and less current consumption. Based on these characteristics, it is opportunistic to strengthen MLC flash by introducing hit-flipping that reshapes state proportions on MLC pages. In this paper. we present a holistic study of bit-flipping schemes upon MLC flash in theory and practice. Specifically, we systematically investigate effective bit-flipping schemes and propose four new schemes on manipulating MLC states. We further design a generic implementation framework, named MLC bit-flipping framework, to implement bit-flipping schemes within solid state drives controllers, nicely integrating with existing system-level optimizations to further improve overall performance. The experimental results demonstrate that our proposed bit-flipping schemes standalone can reduce up to 28% cell damages and 53% retention errors. Our circuit-level simulation manifests that the bit-flipping latency on a page is less than 4 mu s when using 8K logic gates.

  • 1167802.
    Zhang, Wenji
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Construction and calibration of a Kibble balance2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Kibble Balance is a device that can measure the mass by using the magnetic force acting on a current carrying coil. The aim of this experiment is to construct and calibrate a Kibble balance, and use it to measurements of small masses. A PID-controller written in LabView program is developed to control the balance. The calibration of the balance is done in the velocity mode and the corresponding BL-term is measured BL = 6.5(2)x10-2 (T·m). The linear relation between the mass and the current through the coil is found mass(mg) = 6.2(3) x I (mA) .

  • 1167803.
    Zhang, Wenjie
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Gap Analysis of ISO 26000 in Two Atlas Copco Companies in China:: Atlas Copco (Nanjing) Construction and Mining Equipment Co., Ltd. and Wuxi Pneumatech Air/ Gas Purity Equipment Co., Ltd. 2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Social Responsibility(SR)is gathering accumulative attentionrecently.It has become a key criterion of business campaign among companies.This thesis studiesthe current SR performancein two branch companies inAtlas Copco (China), Atlas Copco (Nanjing) Construction and Mining Equipment Ltd. andWuxi Pneumatech Air/Gas Purity Equipment Ltd.Interviews were made separately with company staff, including employees from management level and staff from workshop. ISO 26000 was adoptedas aguiding standard when conducting SR investigation and following analysing work.Core subjects of ‘Labour Practices’, ‘the Environment’ and ‘Community involvement and development’ in ISO 26000 were thethreeresearching aspects in the work. For each detailed actions and expectations in the subject, particular comments and acorresponding rating score aregiven according to its status quo. These rating scoresare utilized in the gap analysing process to illustrate the differences between the current SR situation and theexpectations illustrated in ISO 26000.Moreover, the disparity between twoselected companies is alsodefined by illustrating theirfinal scores on each issueina radar chart.As a result from the assessment,bothcompanies have a far way to go to entirely accomplish ISO 26000’s requirements. For the core subject which is strong at, their current measures need to be kept and finely turned; for the weak core subjects, more attentions should be attracted and concrete actions should be conducted.

    Social Responsibility(SR)is gathering accumulative attentionrecently.It has become a key criterion of business campaign among companies.This thesis studiesthe current SR performancein two branch companies inAtlas Copco (China), Atlas Copco (Nanjing) Construction and Mining Equipment Ltd. andWuxi Pneumatech Air/Gas Purity Equipment Ltd.Interviews were made separately with company staff, including employees from management level and staff from workshop. ISO 26000 was adoptedas aguiding standard when conducting SR investigation and following analysing work.Core subjects of ‘Labour Practices’, ‘the Environment’ and ‘Community involvement and development’ in ISO 26000 were thethreeresearching aspects in the work. For each detailed actions and expectations in the subject, particular comments and acorresponding rating score aregiven according to its status quo. These rating scoresare utilized in the gap analysing process to illustrate the differences between the current SR situation and theexpectations illustrated in ISO 26000.Moreover, the disparity between twoselected companies is alsodefined by illustrating theirfinal scores on each issueina radar chart.As a result from the assessment,bothcompanies have a far way to go to entirely accomplish ISO 26000’s requirements. For the core subject which is strong at, their current measures need to be kept and finely turned; for the weak core subjects, more attentions should be attracted and concrete actions should be conducted.

     

  • 1167804.
    Zhang, Wenjie
    Blekinge Institute of Technology, School of Planning and Media Design.
    Managing Traffic Congestion-Case study of Hangzhou2011Independent thesis Advanced level (degree of Master (One Year))Student thesis
    Abstract [en]

    Hangzhou is located in the east of China as one of most important cities in Yangtze River delta. With the rapid development of economy in the last three decades, Hangzhou, like many other Chinese cities, has met some challenges. Traffic congestion in Hangzhou is the one I want to talk about in this master thesis. Traffic congestion became to trouble people’s lives in the past decade, following with dramatic urbanization. People spent much more time on travel, and their quality of lives were threatened. My thesis includes four parts: introduction of Hangzhou, theories and instruments on reducing traffic congestion, instruments have been used in Hangzhou, and recommendation for Hangzhou’s transportation. Firstly, Hangzhou’s background information was discussed. Population and number of vehicles can be seen as the main reasons for traffic congestion in Hangzhou. Also other problems are listed: old roads structure, mingling of different transits, low efficient of public transit, and poor management. There are policy and planning from national and local government, which is related to Hangzhou’s traffic system. At the end of this chapter I presented my research question: how to reduce Hangzhou’s traffic congestion. Secondly, I discussed theories and instruments have been used to reduce traffic congestion. Traffic principles were introduced: triple convergence and ‘offsetting by growth’, which should not be ignored when people talk about traffic congestion. Then I separated instruments, which used to reduce traffic congestion, into three parts: physical instruments, market instruments, regulatory instruments, and discussed some instruments in these three parts. Thirdly, my attention was focused on Hangzhou’s efforts on reducing traffic congestion. These instruments also can be divided into three parts. Since Hangzhou is in the process of urbanization, physical instruments were used most widely to reduce traffic congestion in Hangzhou. But few market instruments and regulatory instruments have been adopted. I compared instruments used in Hangzhou with other cities’ instruments, and analyzed effects of instruments used in these cites. Through comparison, I found that integrated instruments are necessary when people want to reduce traffic congestion. Only physical instruments or market instruments can not reduce traffic congestion efficiently. At last, I list some accomendations for Hangzhou to reduce traffic congestion, which could be classified as supply side instruments and demand side instruments. Hangzhou has put many efforts in supply side, but few in demand side, and this unbalance between supply side and demand side makes effects of reducing traffic congestion limited. In general, supply side approaches are similar with physical instruments, and demand side approaches are similar with market instruments and regulatory instruments. Hangzhou should continue to improve physical instruments, such as improving public transport system, which can gives people more choices for traveling. Also Hangzhou should put much more efforts on demand side instruments, which can control private cars directly.

  • 1167805.
    Zhang, Wenjie
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    Materials management of Chinese SMEs in processing industry2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 1167806. Zhang, Wenjing
    et al.
    Dai, Min
    Fridberger, Anders
    Karolinska Institutet, Stockholm, Sweden.
    Hassan, Ahmed
    Degagne, Jacqueline
    Neng, Lingling
    Zhang, Fei
    He, Wenxuan
    Ren, Tianying
    Trune, Dennis
    Auer, Manfred
    Shi, Xiaorui
    Perivascular-resident macrophage-like melanocytes in the inner ear are essential for the integrity of the intrastrial fluid-blood barrier2012In: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 109, no 26, p. 10388-10393Article in journal (Refereed)
    Abstract [en]

    The microenvironment of the cochlea is maintained by the barrier between the systemic circulation and the fluids inside the stria vascularis. However, the mechanisms that control the permeability of the intrastrial fluid-blood barrier remain largely unknown. The barrier comprises endothelial cells connected to each other by tight junctions and an underlying basement membrane. In a recent study, we found that the intrastrial fluid-blood barrier also includes a large number of perivascular cells with both macrophage and melanocyte characteristics. The perivascular-resident macrophage-like melanocytes (PVM/Ms) are in close contact with vessels through cytoplasmic processes. Here we demonstrate that PVM/Ms have an important role in maintaining the integrity of the intrastrial fluid-blood barrier and hearing function. Using a cell culture-based in vitro model and a genetically induced PVM/M-depleted animal model, we show that absence of PVM/Ms increases the permeability of the intrastrial fluid-blood barrier to both low- and high-molecular-weight tracers. The increased permeability is caused by decreased expression of pigment epithelial-derived factor, which regulates expression of several tight junction-associated proteins instrumental to barrier integrity. When tested for endocochlear potential and auditory brainstem response, PVM/M-depleted animals show substantial drop in endocochlear potential with accompanying hearing loss. Our results demonstrate a critical role for PVM/Ms in regulating the permeability of the intrastrial fluid-blood barrier for establishing a normal endocochlear potential hearing threshold.

  • 1167807.
    Zhang, Wenjun
    et al.
    Chinese Academic Science, Peoples R China .
    Wu, Yulei
    Chinese Academic Science, Peoples R China .
    Bao, Qinye
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Fang, Junfeng
    Chinese Academic Science, Peoples R China .
    Morphological Control for Highly Efficient Inverted Polymer Solar Cells Via the Backbone Design of Cathode Interlayer Materials2014In: ADVANCED ENERGY MATERIALS, ISSN 1614-6832, Vol. 4, no 12, p. 1400359-Article in journal (Refereed)
    Abstract [en]

    Two alcohol-soluble organic molecules are synthesized and introduced into inverted organic solar cells as the cathode interlayer. A power conversion efficiency as high as 9.22% is obtained by using the more hydrophobic molecule FTBTF-N as the cathode interlayer. Morphological studies suggest that design of the backbone can help to enhance short-circuit current density and fill factor.

  • 1167808.
    Zhang, Wenliang
    et al.
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering. National Engineering Laboratory for Electric Vehicles and the Collaborative Innovation Centre for Electric Vehicles in Beijing.
    Wang, Zhenpo
    School of Mechnical Engineering, Beijing Institute of Technology.
    Zou, Changfu
    Department of Electrical Engineering, Chalmers University of Technology.
    Drugge, Lars
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Nybacka, Mikael
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Vehicle Dynamics.
    Advanced Vehicle State Monitoring:: Evaluating Moving Horizon Estimators and Unscented Kalman Filter2019In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 68, no 6, p. 5430-5442, article id 8682143Article in journal (Refereed)
    Abstract [en]

    Active safety systems must be used to manipulate the dynamics of autonomous vehicles to ensure safety. To this end, accurate vehicle information, such as the longitudinal and lateral velocities, is crucial. Measuring these states, however, can be expensive, and the measurements can be polluted by noise. The available solutions often resort to Bayesian filters such as the Kalman filter, but can be vulnerable and erroneous when the underlying assumptions do not hold. With its clear merits in handling nonlinearities and uncertainties, moving horizon estimation (MHE) can potentially solve the problem and is thus studied for vehicle state estimation. This paper designs an unscented Kalman filter, standard MHE, modified MHE and recursive least squares MHE to estimate critical vehicle states, respectively. All the estimators are formulated based upon a highly nonlinear vehicle model that is shown to be locally observable. The convergence rate, accuracy and robustness of the four estimation algorithms are comprehensively characterised and compared under three different driving manoeuvres. For MHE-based algorithms, the effects of horizon length and optimisation techniques on the computational efficiency and accuracy are also investigated.

  • 1167809.
    Zhang, Wenmin
    et al.
    Zhejiang University.
    Y Yu, M
    Zhejiang University.
    Karimov, A R
    Russian Academy of Science.
    Stenflo, Lennart
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics . Linköping University, The Institute of Technology.
    Energy coupling among the degrees of freedom in an electron-positron plasma2010In: JOURNAL OF PLASMA PHYSICS, ISSN 0022-3778, Vol. 76, p. 329-335Article in journal (Refereed)
    Abstract [en]

    Nonlinear coupling of the motion in the three spatial degrees of freedom of a cold fluid electron-positron plasma is investigated. Exact, solutions describing expanding flows with oscillations are obtained. It is found that the energy in the irrotational flow component is in general transferred to the rotational components, but not in the reversed direction. Furthermore, since the density evolution need not be related to all the three flow components, oscillations in one or two of the flow fields can be purely electromagnetic and are not accompanied by density oscillations.

  • 1167810.
    Zhang, Wenmin
    et al.
    Zhejiang University, Peoples R China .
    Yu, M Y
    Zhejiang University, Peoples R China .
    Karimov, A R
    Russian Academic Science, Russia .
    Stenflo, Lennart
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Intense oscillations in the expansion of an inhomogeneous cylindrical electron-positron layer2013In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 88, no 5, p. 055501-Article in journal (Refereed)
    Abstract [en]

    Large amplitude oscillations in the expansion of a cylindrical electron-positron plasma layer are investigated. The cold fluid equations and the Poissons equation are solved non-perturbatively in order to allow for very large amplitude oscillations. It is found that oscillations are self-excited during the expansion and can grow to very large amplitudes as the expansion slows down with time and the plasma density decreases. The kinetic energy of the expansion is thereby converted into that of the oscillations.

  • 1167811.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    A review on biofuels for transportation2006In: Asia Biofuels Conference & Expo IV, 2006, Beijing., 2006Conference paper (Other scientific)
    Abstract [en]

    Energy use in the transport sector is heavily dependent on crude oil which is running out in a limited time. Under the pressure of oil dependency and climate change, the possibility of producing transportation fuels from biomass and wastes has been a more and more attractive subject. The first generation of biofuels for transportation, such as bioethanol, biodiesel and biogas produced from agricultural activities have been successfully introduced into the transport market in a number of countries. From the viewpoint of fuel potential, economics, environment, land use, water use and chemical fertilizer use, there is a strong preference for the use of woody biomass and various forest/agricultural residues as the feedstock. Thus, the production of second generation of biofuels i.e. synthetic transportation fuels such as methanol, DME, FT-diesel and hydrogen through biomass gasification seems promising. This paper is trying to review the present market of the first generation of bio-automotive fuels and the technology development of the second generation of bio-automotive fuels. It can be concluded that the second generation of bio-automotive fuels is on the way to a breakthrough in the transport markets of industrial countries especially for those countries with a strong forest industry. The first generation will remain as favourable bio-automotive fuels in the developing countries.

  • 1167812.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Automotive fuels from biomass via gasification2010In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 91, no 8, p. 866-876Article in journal (Refereed)
    Abstract [en]

    There exists already a market of bioautomotive fuels i.e. bioethanol and biodiesel produced from food crops in many countries. From the viewpoint of economics, environment, land use, water use and chemical fertilizer use, however, there is a strong preference for the use of woody biomass and various forest/agricultural residues as the feedstock. Thus, the production of 2nd generation of bioautomotive fuels i.e. synthetic fuels such as methanol, ethanol, DME, FT-diesel, SNG and hydrogen through biomass gasification seems promising. The technology of producing synthetic fuels are well established based on fossil fuels. For biomass, however, it is fairly new and the technology is under development. Starting from the present market of the 1st generation of bio-automotive fuels, this paper is trying to review the technology development of the 2nd generation bio-automotive fuels. The production of syngas is emphasized which suggests appropriate gasifier design for a high quality syngas production. A number of bio-automotive fuel demonstration plant will be presented, which gives the state of the art in the development of BTS (biomass to synthetic fuels) technologies. It can be concluded that the 2nd generation bio-automotive fuels is on the way to a breakthrough in the transport markets of industrial countries especially for those countries with a strong forest industry.

  • 1167813.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Bioethanol market and perspective2007Report (Other academic)
  • 1167814.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Biomass pellet perspective and market2007Report (Other academic)
  • 1167815.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Peat perspective and market2007Report (Other academic)
  • 1167816.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    PROCESS SIMULATION OF CIRCULATING FLUIDIZED BEDS - mid term assessment report 2000Report (Other scientific)
  • 1167817.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    PROCESS SIMULATION OF CIRCULATING FLUIDIZED BEDS - yearly report1999Report (Other scientific)
  • 1167818.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    PROCESS SIMULATION OF CIRCULATING FLUIDIZED BEDS - yearly report: reporting the JOR3CT980306 project of 4th EU-framework Programme2000Report (Other academic)
  • 1167819.
    Zhang, Wennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    TRANSPORTATION FUELS FROM BIOMASS VIA GASIFICATION: 2nd World Conference and Exhibition on Biomass for Energy and Industry, May 2004, Rome, Italy2004Conference paper (Other scientific)
    Abstract [en]

    There exists already a market of transportation fuels i.e. bioethanol and biodiesel produced from food crops in several countries. From the viewpoint of economics, environment, land use, water use and chemical fertilizer use, however, there is a strong preference for the use of woody biomass and various forest/agricultural residues as the feedstock. Thus, the production of transportation fuels through biomass gasification seems the most promising. The technology of producing liquid fuels such as methanol and FT-diesel is well established based on fossil fuels. For biomass, however, it is fairly new. This paper critically reviews a number of transportation fuels such as methanol, DME, FT-fuels etc. with respect to four criteria: efficiency, economy, environmental impact and end use with emphasis on well-to-wheel efficiency. The production of syngas required is discussed which suggests appropriate gasifier design for a high quality syngas production. It is supposed that ethanol is the best choice to substitute gasoline while FT-diesel is the best choice to substitute diesel.

  • 1167820.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Dai, X
    Söderlind, Ulf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wu, C
    Further test on the Sanya 6MW biomass CFB gasifier2004In: 2nd World Conference and Exhibition on Biomass for Energy, Industry and Climate Protection. Rome, Italy, 10 - 14 May 2004, 2004Conference paper (Other scientific)
    Abstract [en]

    Following a preliminary test on the 6 MW Sanya biomass CFB gasifier (reported in the last conference at Amsterdam), a further test has been carried out focusing on the use of in-bed dolomite in order to reduce the tar content in the product gas. The gas composition and tar contents in the product gas at different temperatures were measured and analyzed. The results show that there is no big difference between two cases with and without dolomite at low temperature of 700C. However, at high temperature of 900C, the tar content was reduced significantly by the addition of in-bed dolomite. Temperature has a strong effect on the efficiency of dolomite catalyst

  • 1167821.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Dai, X.
    Söderlind, Ulf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Wu, C.
    Luo, X.
    A PRELIMINARY TEST ON AN INDUSTRIAL BIOMASS CFB GASIFIER 2002In: 12th European Biomass Conference: Vol. 1, 2002, p. 745-748Conference paper (Other scientific)
    Abstract [en]

    A test was carried out on an 6 MW industrial biomass atmospheric CFB gasifier in a power plant. The gas composition, NH3 and tar contents in the product gas at different temperatures were measured and analyzed. Ash (char in the present case) analysis was also made to make mass balance of chemical element in solid and gas phases during gasification based on Si balance analysis. The measurement results show that a gas productivity of 2 Nm3/kg (daf biomass) with gas LHV of 5MJ/Nm3 can be achieved at 750℃.The conversion of fuel-bound nitrogen (FBN) to NH3 ranges from 6 wt% to 70 wt% depending on temperature. Tar content in the product gas ranges from 2.5 to 16.7 g/m3. Small fractions of H, O, N, Cl and S contents in fuel remain in the ash while most of mineral metal element remains in the ash.

  • 1167822.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Forsman, B.
    Söderlind, U.
    Biofuels in Sweden2005In: Proceedings of the 7th World Congress on Recovery Recycling and Reintegration, 2005Conference paper (Other scientific)
    Abstract [en]

    Biomass residual from forest has been utilized in a large scale in Sweden after full speed development over the past decade, which contributes about 20% of the total energy consumption. This is a big event for an industrial country to shift fossil fuel-based society to a sustainable society. The well established biofuel market in Sweden is, in principle, attributed to the good synergy of a strong forest industry with the energy sector, to a good district heating system, and to a favorable tax system. In this paper, the authors are trying to present a picture of how biomass residual is shaping the Swedish energy system in the past and for the future. The production of heat, electricity and transportation fuels will be discussed. A number of critic points associated to biofuel potential, economy, environmental impact, end-use, as well as to biomass conversion technologies such as combustion, gasification and biological processes will be discussed. The advances of research and technology development in Sweden will be overviewed. Swedish bioenergy industry shows a good example in the world regarding biomass residual utilization as a renewable energy. The practices and experiences might be useful to other countries.

  • 1167823.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    He, Jie
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Engstrand, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Björkqvist, Olof
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Economic evaluation on bio-synthetic natural gas production integrated in a thermomechanical pulp mill2015In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 8, no 11, p. 12795-12809Article in journal (Refereed)
    Abstract [en]

    In this study, biorefinery as a concept is applied to thermomechanical pulp (TMP)-based paper production to evaluate the possibility of co-production of synthetic natural gas (SNG), electricity and district heating in addition to mechanical pulp and paper. The combined heat and power plant (CHP) associated to TMP is replaced by a biomass-to-SNG (BtSNG) plant. Implementing BtSNG in a mechanical pulp production line might improve the profitability of a TMP mill and also help to commercialize the BtSNG technology by taking into account of some key issues such as biomass availability, heat utilization, etc. A TMP + BtSNG mathematical model is developed with ASPEN Plus. The model prediction shows that the scale of the TMP + BtSNG mill and SNG price are two strong factors for the implementation of BtSNG in a TMP mill. A BtSNG plant associated to a TMP mill should be built at a scale above 100 MW of biomass thermal input. For the case of Swedish economic condition, commercialization of SNG production as a transport biofuel has not matured yet. Political instruments to support commercialization of transport biofuel are necessary.

  • 1167824.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Henschel, Till
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Söderlind, Ulf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Chemical Engineering.
    Tran, Khan-Quang
    Department of Energy and Process Engineering, Norwegian University of Science and Technology, Trondheim, Norway.
    Han, Xu
    Sunshine Kaidi New Energy Group Co., China.
    Thermogravimetric and Online Gas Analysis on various Biomass Fuels2017In: Energy Procedia, Elsevier, 2017, Vol. 105, p. 162-167Conference paper (Refereed)
    Abstract [en]

    In this work, the biomass property is evaluated based on pyrolysis behavior of biomass fuels by means of TGA and online gas analysis. Wood, sawdust, pine bark, peat, straw, black liquor and microalgae are chosen as the biomass feedstocks for the pyrolysis study. The measurement results show high volatile content for algae and black liquor (around 85%) and low volatile content for pine bark and peat (around 69%). Differently from woody biomass, the DTG curve of straw has a single dominant peak at much lower temperature, which suggests a dominant component of hemicellulose in biomass, while algae and peat have a broader temperature specturm of devolatilization but much lower peak temperature. CO2 is released first and H2 later in the pyrolysis process for all biomass feedstocks, whileas the peak of CO formation follows CO2 formation trend for most feedstocks used, except for peat and pine bark which give a peak later at high temperature. This indicates secondary reactions of tar cracking, steam reforming and char gasification.

  • 1167825.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Johnsson, F
    Johnsson, H
    Leckner, B
    Time-dependent fluctuation characteristics of particle flow in a circulating fluidized bed boiler2001In: Fluidization X : proceedings of the Tenth Engineering Foundation Conference on Fluidization, Beijing, People Republic of China, May 20 - 25, 2001: Conference on Fluidization <10, 2001, Beijing>, New York: United Engineering Foundation , 2001, p. 818-Conference paper (Refereed)
    Abstract [en]

    Measurements of the fluctuations in solids flow in a circulating fluidized bed (CFB) boiler has been carried out with emphasis on the layer of downflowing particles at the furnace walls. Signals of local fluctuations in particle downflow, global pressure drop fluctuations in the upper and bottom zones of the furnace, and in absolute pressure in air plenum, were simultaneously sampled. Spectral and probability analyses on the signals suggest a regular slow fluctuation of the particle suspension flow passing through the core and falling at the wall. The flow of particles in the wall-layer has a wide distribution of densities. The transfer of particles from the core to the wall is the dominant process for the formation and evolution of the wall-layer in the furnace of CFB boilers.

  • 1167826.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Leckner, Bo
    PROCESS SIMULATION OF CIRCULATING FLUIDIZED BEDS WITH COMBUSTION/GASIFICATION OF BIOMASS - The project final report: reporting the JOR3CT980306 project of 4th EU-framework Programme2001Report (Other academic)
  • 1167827.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Söderlind, Ulf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    A review on transportation fuels from biomass syngas: 7th World Congress on Recovery, Recycling and Reintegration, Beijing2005Conference paper (Other scientific)
    Abstract [en]

    There exists already a market of transportation fuels i.e. bioethanol and biodiesel produced from food crops in several countries. From the viewpoint of economics, environment, land use, water use and chemical fertilizer use, however, there is a strong preference for the use of woody biomass and various forest/agricultural residues as the feedstock. Thus, the production of transportation fuels through biomass gasification seems the most promising. The technology of producing liquid fuels such as methanol and FT-diesel is well established based on fossil fuels. For biomass, however, it is fairly new. This paper critically reviews a number of transportation fuels such as methanol, DME, FT-fuels etc. with respect to four criteria: efficiency, economy, environmental impact and end use with emphasis on well-to-wheel efficiency. The production of syngas required is discussed which suggests appropriate gasifier design for a high quality syngas production. It is supposed that ethanol is the best choice to substitute gasoline while FT-diesel is the best choice to substitute diesel.

  • 1167828.
    Zhang, Wennan
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Yu, C
    Tabikh, A
    Dai, X
    Söderlind, Ulf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Adanes, J
    de Diego, L
    García-Labiano, F
    Gayán, P
    Aibeo, A
    Pinho, C
    Andersson, Bertil
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering, Physics and Mathematics.
    Brus, E
    Nordin, A
    Fjällström, T
    Process simulation of circulating fluidized beds with combustion/gasification of biomass.2002In: Twelfth European Biomass Conference - Biomass for Energy, Industry and Climate Protection: European Conference on Biomass for Energy, Industry and Climate Protection 12, 2002, Amsterdam>, Florence: ETA , 2002, p. 1503-Conference paper (Refereed)
    Abstract [en]

    This paper briefly presents the work carried out for the 4th framework Joule project under the contract JOR3CT980306. The project is to build up an integrated mathematical model to predict reactor performance of biomass circulating fluidized bed boiler/gasifier when reactor design, operating conditions and fuel properties are defined. For CFB boilers, the sub-models of combustion, heat transfer, ash deposition on a heat transfer surface and NOx/N2O emission have been developed, and evaluated against the 12 MW Chalmers CFB boiler. For CFB gasifiers, the sub-models of gasification, heat transfer, NH3/HCN emission, alkali ash and tar emissions from the gasifiers are developed. The results have been checked on Sanya 6MW industrial biomass CFB gasifier.

  • 1167829.
    Zhang, Wenquan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Understanding Energy and Carbon Intensities in China: Trends, Projections, and Uncertainties2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Two weeks before the Copenhagen summit on climate change, China officially made a pledge to cut its carbon intensity by 40 to 45 percent below 2005 level by 2020. The thesis has tried to look into the quality and quantity concern of this pledge made by the biggest CO2 emitter in the world. From the existing projections on China’s business as usual (BAU) scenarios to 2020, there are no unanimous conclusions showing whether there is additionality in China’s pledge to reduce 40-45% of its carbon intensity between 2005 and 2020. Further analysis on selected results, we have found scenarios of two frequently cited authorities, namely IEA and EIA are, to some extent, misinterpreted regarding their references/current policies scenarios. On the other hand, several more typical BAU scenarios, like Garnaut’s and ReMIND-R, predicted much lower than 40% reduction rate in the period of 2005-2020. China’s pledge seems achievable with certain extra effort, comparing with historical pathways of several OECD countries, including U.S., Japan, Germany, and Korea. The average period in these four countries to go through China’s abatement path is around 21 years. From a global prospect, China’s pledge is impressive but not enough to address the climate change issue. The biggest uncertainty inherited in the pledge is the uncertain peak year of absolute emissions. The critical movement beyond 2020 pledge is to peak its absolute CO2 emissions as early as possible. Such a challenging target shall be set as no later than 2030 according to our overviews on the related literature.

  • 1167830.
    Zhang, Wensheng
    et al.
    Soochow Univ, Cam Su Genom Resource Ctr, Suzhou 215123, Peoples R China.;Wellcome Sanger Inst, Hinxton CB10 1SA, England..
    Chronis, Constantinos
    Univ Calif Los Angeles, David Geffen Sch Med, Dept Biol & Chem, Los Angeles, CA 90095 USA.;Univ Calif Los Angeles, Eli & Edythe Broad Ctr Regenerat Med & Stem Cell, Los Angeles, CA USA.;Univ Calif Los Angeles, Jonsson Comprehens Canc Ctr, Bioinformat Program, Los Angeles, CA 90024 USA.;Univ Calif Los Angeles, Mol Biol Inst, Los Angeles, CA 90095 USA..
    Chen, Xi
    Wellcome Sanger Inst, Hinxton CB10 1SA, England..
    Zhang, Heyao
    Soochow Univ, Cam Su Genom Resource Ctr, Suzhou 215123, Peoples R China..
    Spalinskas, Rapolas
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Pardo, Mercedes
    Chester Beatty Labs, Inst Canc Res, London, England..
    Chen, Liangliang
    Soochow Univ, Cam Su Genom Resource Ctr, Suzhou 215123, Peoples R China..
    Wu, Guangming
    Max Planck Inst Mol Biomed, Dept Cell & Dev Biol, Rontgenstr 20, D-48149 Munster, Germany..
    Zhu, Zhexin
    Wellcome Sanger Inst, Hinxton CB10 1SA, England..
    Yu, Yong
    Wellcome Sanger Inst, Hinxton CB10 1SA, England..
    Yu, Lu
    Chester Beatty Labs, Inst Canc Res, London, England..
    Choudhary, Jyoti
    Chester Beatty Labs, Inst Canc Res, London, England..
    Nichols, Jennifer
    Univ Cambridge, Wellcome Trust Med Res Council, Stem Cell Inst, Tennis Court Rd, Cambridge CB2 1QR, England..
    Parast, Mana M.
    Univ Calif San Diego, Dept Pathol, La Jolla, CA 92093 USA.;Univ Calif San Diego, Sanford Consortium Regenerat Med, La Jolla, CA 92093 USA..
    Greber, Boris
    Max Planck Inst Mol Biomed, Dept Cell & Dev Biol, Rontgenstr 20, D-48149 Munster, Germany..
    Sahlén, Pelin
    KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Plath, Kathrin
    Univ Calif Los Angeles, David Geffen Sch Med, Dept Biol & Chem, Los Angeles, CA 90095 USA.;Univ Calif Los Angeles, Eli & Edythe Broad Ctr Regenerat Med & Stem Cell, Los Angeles, CA USA.;Univ Calif Los Angeles, Jonsson Comprehens Canc Ctr, Bioinformat Program, Los Angeles, CA 90024 USA.;Univ Calif Los Angeles, Mol Biol Inst, Los Angeles, CA 90095 USA..
    The BAF and PRC2 Complex Subunits Dpf2 and Eed Antagonistically Converge on Tbx3 to Control ESC Differentiation2019In: Cell Stem Cell, ISSN 1934-5909, E-ISSN 1875-9777, Vol. 24, no 1, p. 138-+Article in journal (Refereed)
    Abstract [en]

    BAF complexes are composed of different subunits with varying functional and developmental roles, although many subunits have not been examined in depth. Here we show that the Baf45 subunit Dpf2 maintains pluripotency and ESC differentiation potential. Dpf2 co-occupies enhancers with Oct4, Sox2, p300, and the BAF subunit Brg1, and deleting Dpf2 perturbs ESC self-renewal, induces repression of Tbx3, and impairs mesendodermal differentiation without dramatically altering Brg1 localization. Mesendodermal differentiation can be rescued by restoring Tbx3 expression, whose distal enhancer is positively regulated by Dpf2-dependent H3K27ac maintenance and recruitment of pluripotency TFs and Brg1. In contrast, the PRC2 subunit Eed binds an intragenic Tbx3 enhancer to oppose Dpf2-dependent Tbx3 expression and mesendodermal differentiation. The PRC2 subunit Ezh2 likewise opposes Dpf2-dependent differentiation through a distinct mechanism involving Nanog repression. Together, these findings delineate distinct mechanistic roles for specific BAF and PRC2 subunits during ESC differentiation.

  • 1167831.
    Zhang, Wenxin
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering, Environmental Physics.
    Long-term Trend of Evapotranspiration in Sweden Affected by Climate Change or Land-use Change.2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Evapotranspiration (ET) is an essential component of water cycle as it is an interlinkage between atmosphere, vegetation and soil surface in terms of energy and water balance. However, whether potential ET has the same tendency to change as actual ET and how ET trend (based on the difference between precipitation and runoff) is directly driven by dominant meteorological factors alone or combined with ecosystem‘s feedbacks to climate change (like land-use change) is still under the discussion. In this report, five ET parameterizations within two rainfall-runoff models [Coupled Heat and Mass Transfer Model (CoupModel) and Hydrologiska Byråns Vattenbalansavdelning (HBV)] have been set up based on six subcatchments of Sweden. The scenario derived from CoupModel shows that the trend of ET is affected by the change of land-use, where soil evaporation tends to shift to transpiration and interception evaporation. However, HBV model produces the other scenario: the trend of ET is merely the consequence of meteorological factors. Increased ET is contributed by increased interception evaporation due to the increased precipitation. After identifying the time split of changing ET trends, a dynamic simulation constructed both from HBV and CoupModel indicate that the increased total ET is primarily from increased ET in winter time. More and more interceptive water loss and transpiration resulted from land-use change due to more vegetation. On the other hand, land-use change is also a feed back to climate change. Transpiration controlled by the mechanism of stomata and water uptake controlled by reduction of soil moisture is highly related to variations of climatic conditions.

  • 1167832. Zhang, Wenxin
    et al.
    Miller, Paul A.
    Smith, Benjamin
    Wania, Rita
    Koenigk, Torben
    SMHI, Research Department, Climate research - Rossby Centre.
    Doescher, Ralf
    SMHI, Research Department, Climate research - Rossby Centre.
    Tundra shrubification and tree-line advance amplify arctic climate warming: results from an individual-based dynamic vegetation model2013In: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 8, no 3, article id 034023Article in journal (Refereed)
    Abstract [en]

    One major challenge to the improvement of regional climate scenarios for the northern high latitudes is to understand land surface feedbacks associated with vegetation shifts and ecosystem biogeochemical cycling. We employed a customized, Arctic version of the individual-based dynamic vegetation model LPJ-GUESS to simulate the dynamics of upland and wetland ecosystems under a regional climate model-downscaled future climate projection for the Arctic and Subarctic. The simulated vegetation distribution (1961-1990) agreed well with a composite map of actual arctic vegetation. In the future (2051-2080), a poleward advance of the forest-tundra boundary, an expansion of tall shrub tundra, and a dominance shift from deciduous to evergreen boreal conifer forest over northern Eurasia were simulated. Ecosystems continued to sink carbon for the next few decades, although the size of these sinks diminished by the late 21st century. Hot spots of increased CH4 emission were identified in the peatlands near Hudson Bay and western Siberia. In terms of their net impact on regional climate forcing, positive feedbacks associated with the negative effects of tree-line, shrub cover and forest phenology changes on snow-season albedo, as well as the larger sources of CH4, may potentially dominate over negative feedbacks due to increased carbon sequestration and increased latent heat flux.

  • 1167833.
    ZHANG, WILLIAM
    KTH, School of Computer Science and Communication (CSC).
    Challenges for Web AnalyticsApplications on Mobile Platforms2013Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The mobile industry has seen tremendous growth over the last decade, with both mobile

    hardware and software rapidly improving. This opens up new possibilities for mobile

    applications and allows them to expand into areas that were previously reserved for

    desktop applications. One of these fields is web analytics, which Vizzit wishes to explore

    by creating a prototype mobile web analytics application.

    This master thesis project investigates whether mobile devices are a suitable platform for

    web analytics applications, and what challenges are involved, both from a general, topdown

    perspective, as well as a more detailed developer perspective.

    The results of the investigation suggests that it is definitely possible to create a mobile

    based web analytics application, but not without challenges and limitations. For example,

    tablets proved to be much more suitable than smart phones because of their larger displays.

    One must also consider crucial factors such as the application type (native or web-based)

    and target platform and their implications. For example, JavaScript is used for almost all

    mobile web development, but there are some limitations and challenges posed by the

    language itself. Finally, for data-driven applications such as web analytics programs,

    efficiency problems and usability issues also arise when fetching large amounts of data

    remotely.

  • 1167834.
    Zhang, WM
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Kapyla, J
    Puranen, JS
    Knight, CG
    Tiger, CF
    Pentikainen, OT
    Johnson, MS
    Farndale, RW
    Heino, J
    Gullberg, D
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    alpha 11beta 1 integrin recognizes the GFOGER sequence in interstitialcollagens.2003In: J Biol Chem, Vol. 278, p. 7270-Article in journal (Refereed)
  • 1167835.
    Zhang, WM
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Popova, SN
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Bergman, C
    Velling, T
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Gullberg, MK
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Gullberg, D
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Medical Biochemistry and Microbiology.
    Analysis of the human integrin alpha11 gene (ITGA11) and its promoter.2002In: Matrix Biol, Vol. 21, p. 513-Article in journal (Refereed)
  • 1167836.
    Zhang, WW
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Lempessi, H
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Olsson, Y
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Amyloid angiopathy of the human brain: immunohistochemical studies using markers for components of extracellular matrix, smooth muscle actin and endothelial cells1998In: Acta Neuropathol, Vol. 96, p. 558-Article in journal (Refereed)
  • 1167837.
    Zhang, WW
    et al.
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    Zhang, Y
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Medicine, Department of Genetics and Pathology.
    The angiopathy of subcortical arteriosclerotic encephalopathy (Binswanger's disease): immunohistochemical studies using markers for components of extracellular matrix, smooth muscle actin and endothel1997In: Acta Neuropathol (Berl), Vol. 93, p. 219-Article in journal (Refereed)
  • 1167838. Zhang, X.
    et al.
    Chen, L.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Mao, J.
    Wu, W.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Hua, J.
    Photovoltaic properties of bis(octyloxy)benzo-[c][1,2,5]thiadiazole sensitizers based on an N,N-diphenylthiophen-2-amine donor2014In: Journal of Materials Chemistry C, ISSN 2050-7526, Vol. 2, no 20, p. 4063-4072Article in journal (Refereed)
    Abstract [en]

    Three D-A-π-A sensitizers (DOBT-IV to DOBT-VI) with N,N- diphenylthiophen-2-amine as the donor and bis(octyloxy)benzo-[c][1,2,5] thiadiazole (DOBT) as the auxiliary acceptor have been designed and synthesized. Their applications to dye-sensitized solar cells with I-/I 3 - and Co(ii)/(iii) electrolytes were measured and characterized. Via fine tuning of the π-bridge, the highest photoelectric conversion efficiency of 7.16% was obtained with Jsc = 16.88 mA cm-2, Voc = 0.662 V and FF = 64.03% for the DOBT-V based dye-sensitized solar cells using the I-/I3 - electrolyte under standard global AM1.5 solar conditions. A photoelectric conversion efficiency of 6.14% was obtained with Jsc = 11.35 mA cm-2, Voc = 0.760 V and FF = 71.16% with the Co(ii)/(iii) electrolyte under standard global AM1.5 solar conditions. The optical and electrochemical properties and the photovoltaic performance were evaluated and investigated using density functional theory calculations, a behavior study of the four performance parameters with dependence of the incident light intensity, electrochemical impedance spectroscopy and intensity-modulated photo-voltage spectrometry.

  • 1167839. Zhang, X.
    et al.
    Chen, R.
    Wang, P.
    Shu, J.
    Zhang, H.
    Song, H.
    Xu, J.
    Zhang, Pei
    KTH, School of Engineering Sciences (SCI), Applied Physics, Materials and Nanophysics. Nanjing University, Nanjing, China.
    A soft chemistry-based route to enhanced photoluminescence of terbium ions and tin oxide nanocrystals codoped silica thin films2018In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 452, p. 96-101Article in journal (Refereed)
    Abstract [en]

    Tb3+ ions and SnO2 nanocrystals (NCs) codoped silica films are fabricated by a soft chemistry-based approach. Via precise adjustment of Sn amounts in precursors, the size and number density of SnO2 NCs can be well controlled by a restrictive crystallization process. The characteristic emission intensity of Tb3+ ions at 541 nm can be greatly enhanced by two orders of magnitude if sensitized by SnO2 NCs with optimized size and number density. Photoluminescence excitation spectra of the films containing different Sn amounts indicate the non-radiative energy transfer process that takes place between Tb3+ ions and surface of SnO2 NCs. The photoluminescence intensity decay curves suggest two kinds of possible occurrence states of Tb3+ ions in codoped samples. All these results suggest the SnO2 NCs represent ideal sensitizers to effectively promote photoluminescence efficiency of Tb3+ ions. Particularly, the soft chemistry-based method reported here is very flexible for the fabrication of rare earth ions doped amorphous thin films, permitting the precise control of size and number density of NCs as sensitizers. We anticipate this fabrication strategy greatly enriches the techniques for the preparation of thin films, providing great promise for the realization of on-chip integration of silica-based optical lasers and amplifiers.

  • 1167840. Zhang, X.
    et al.
    Ebrahimi, M.
    Huang, L.
    Li, G.
    Jantsch, Axel
    KTH, School of Information and Communication Technology (ICT), Electronics and Embedded Systems.
    A routing-level solution for fault Detection, masking, and Tolerance in NoCs2015In: Proceedings - 23rd Euromicro International Conference on Parallel, Distributed, and Network-Based Processing, PDP 2015, IEEE conference proceedings, 2015, p. 365-369Conference paper (Refereed)
    Abstract [en]

    Faults may occur in numerous locations of a router in a NoC platform. Compared with the faults in the data path, faults in the control path may cause more severe effects which may result in crashing the entire system. Most of the current efforts in literature focus on disabling a router when a fault is detected. Considering this level of coarse-granularity, the functioning parts of a router have to be unnecessarily disabled which may severely affect the performance or functionality of the on-chip network. To cope with this problem, in this paper we propose a mechanism to tolerate faults in the control path which largely avoid disabling a router as long as the fault is not severe. This mechanism is called DMT, standing for three distinguishing characteristics of the proposed method as fault Detection, fault Masking and fault Tolerance. The proposed mechanism can efficiently detect the faults expressed as illegal turns while it has the capability to tolerate faults without a prior knowledge on where and why a fault has happened.

  • 1167841. Zhang, X.
    et al.
    Ebrahimi, Masoumeh
    KTH, School of Information and Communication Technology (ICT), Industrial and Medical Electronics.
    Huang, L.
    Li, G.
    Fault-resilient routing unit in NoCs2016In: International System on Chip Conference, IEEE Computer Society, 2016, p. 164-169Conference paper (Refereed)
    Abstract [en]

    With aggressive technology scaling in deep submicron era, burgeoning transistors make chips more susceptible to failures. It is inevitable that process variation is gradually becoming a crucial challenge in the IC design. In addition, aging leads to faults, shortening the lifetime of the circuits. Networks-on-chip also come to the problems caused by variations and aging, leading to degraded performance and erroneous behaviors. Faults may occur in numerous locations of the on-chip networks and once they occur in the control path, more severe effects such as deadlock and livelock are expected. In this paper, we present a fine-grained mechanism to tolerate faults in the routing computation units without disabling the faulty routers. By applying this mechanism, routing and packet-receiving services are separated. The faulty routing computation unit is replaced by a light-weight redundant circuit, providing static but reliable routing services. The other components in this router are still functional retaining the on-chip performance. Experimental results indicate that the on-chip network with the proposed mechanism is fault-tolerant when 14% of all routing computation modules are suffering from faults. The area overhead and power consumption of the proposed method is around 7.29% and 6.20% over the baseline approach.

  • 1167842. Zhang, X. F.
    et al.
    Huang, D. G.
    Feng, C.
    Chen, C. N.
    Liu, Q. T.
    Sun, Licheng C.
    catena-Poly (1,10-phenanthroline-kappa N-2,N ')manganese(II) -mu-L-tartrato-kappa O-4(1),O-2: O-3,O-4 hexahydrate2003In: Acta Crystallographica Section C: Crystal Structure Communications, ISSN 0108-2701, E-ISSN 1600-5759, Vol. 59, p. M402-M404Article in journal (Refereed)
    Abstract [en]

    The title compound, {[Mn(C4H4O6)(C12H8N2)] . 6H(2)O}(n), has a linear chain structure containing monomeric [ Mn( C4H4O6)( C12H8N2)] repeat units. Each manganese ion is six-coordinate, with the two phenanthroline N atoms [Mn - N = 2.229 (2) and 2.235 (2) Angstrom] and four O atoms from two tartrate anions [Mn - O-COO = 2.1252 (19) and 2.1310 (19) Angstrom, and Mn - O-OH = 2.2404 (19) and 2.2424 (19) Angstrom] forming a seriously distorted octahedral coordination environment. Six water molecules exist outside every repeat unit as solvate molecules. Extensive hydrogen-bonding interactions and pi-pi stacking of the phenanthroline moieties exist between the chains.

  • 1167843. Zhang, X F
    et al.
    Meining, Winfried
    Södertörn University, Avdelning Naturvetenskap.
    Cushman, M
    Haase, I
    Fischer, M
    Bacher, A
    Ladenstein, R
    A structure-based model of the reaction catalyzed by lumazine synthase from Aquifex aeolicus2003In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 328, no 1, p. 167-182Article in journal (Refereed)
    Abstract [en]

    6,7-Dimethyl-8-ribityllumazine is the biosynthetic precursor of riboflavin, which, as a coenzyme, plays a vital role in the electron transfer process for energy production in all cellular organisms. The enzymes involved in lumazine biosynthesis have been studied in considerable detail. However, the conclusive mechanism of the reaction catalyzed by lumazine synthase has remained unclear. Here, we report four crystal structures of the enzyme from the hyperthermophilic bacterium Aquifex aeolicus in complex with different inhibitor compounds. The structures were refined at resolutions of 1.72 Angstrom, 1.85 Angstrom, 2.05 Angstrom and 2.2 Angstrom, respectively. The inhibitors have been designed in order to mimic the substrate, the putative reaction intermediates and the final product. Structural comparisons of the native enzyme and the inhibitor complexes as well as the kinetic data of singlesite mutants of lumazine synthase from Bacillus subtilis showed that several highly conserved residues at the active site, namely Phe22, His88, Arg127, Lys135 and Glu138 are most likely involved in catalysis. A structural model of the catalytic process, which illustrates binding of substrates, enantiomer specificity, proton abstraction/donation, inorganic phosphate elimination, formation of the Schiff base and cyclization is proposed.

  • 1167844. Zhang, X F
    et al.
    Meining, Winfried
    Södertörn University, Avdelning Naturvetenskap.
    Fischer, M
    Bacher, A
    Ladenstein, R
    X-ray structure analysis and crystallographic refinement of lumazine synthase from the hyperthermophile Aquifex aeolicus at 1.6 angstrom resolution: Determinants of thermostability revealed from structural comparisons2001In: Journal of Molecular Biology, ISSN 0022-2836, E-ISSN 1089-8638, Vol. 306, no 5, p. 1099-1114Article in journal (Refereed)
    Abstract [en]

    An open reading frame optimized for expression of 6,7-dimethyl-8-ribityllumazine synthase of the hyperthermophilic bacterium Aquifex aeolicus in Escherichia coli was synthesized and expressed in a recombinant E. coli strain to a level of around 15%. The recombinant protein was purified by heat-treatment and gel-filtration. The protein was crystallized in the cubic space group 123 with the cell dimensions a = b = c = 180.8 Angstrom, and diffraction data were collected to 1.6 Angstrom resolution. The structure was solved by molecular replacement using lumazine synthase from Bacillus subtilis as search model. The structure of the A. aeolicus enzyme was refined to a resolution of 1.6 Angstrom. The spherical protein consists of 60 identical subunits with strict icosahedral 532 symmetry. The subunit fold is closely related to that of the B. subtilis enzyme (rmsd 0.80 Angstrom). The extremely thermostable lumazine synthase from A. aeolicus has a melting temperature of 119.9 degreesC. Compared to other icosahedral and pentameric lumazine synthases, the A. aeolicus enzyme has the largest accessible surface presented by charged residues and the smallest surface presented by hydrophobic residues. It also has the largest number of ion-pairs per subunit. Two ion-pair networks involving two, respectively three, stacking arginine residues assume a distinct role in linking adjacent subunits. The findings indicate the influence of the optimization of hydrophobic and ionic contacts in gaining thermostability.

  • 1167845.
    Zhang, X.
    et al.
    Shanxi Univ, Inst Environm Sci, Taiyuan, Shanxi, Peoples R China.
    Fan, Q.
    Shanxi Univ, Inst Environm Sci, Taiyuan, Shanxi, Peoples R China.
    Bai, X.
    Shanxi Univ, Inst Environm Sci, Taiyuan, Shanxi, Peoples R China.
    Li, T.
    Shanxi Univ, Inst Environm Sci, Taiyuan, Shanxi, Peoples R China.
    Zhao, Z.
    Fudan Univ, Sch Publ Hlth, Shanghai, Peoples R China.
    Fan, X.
    Taiyuan Univ Technol, Coll Chem & Chem Engn, Taiyuan, Shanxi, Peoples R China.
    Norbäck, Dan
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Occupational and Environmental Medicine.
    Levels of fractional exhaled nitric oxide in children in relation to air pollution in Chinese day care centres2018In: The International Journal of Tuberculosis and Lung Disease, ISSN 1027-3719, E-ISSN 1815-7920, Vol. 22, no 7, p. 813-819Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To study fractional exhaled nitric oxide (FeNO) levels among pre-school children in day care centres (DCCs) in relation to indoor and outdoor air pollution in northern China.

    DESIGN: This was a cross-sectional study among children aged 5 years from 34 classrooms at 10 randomly selected DCCs in Taiyuan, China. A total of 507 (99%) children participated. Air pollution and carbon dioxide (CO2) levels were measured in the classroom and outside the school. Linear mixed models were applied for statistical analysis.

    RESULTS: The geometric mean FeNO was 9.1 +/- 1.5 parts per billion; 11.6% of children had wheeze, 6.0% had dry cough, 26.4% rhinitis symptoms, 1.6% ever physician-diagnosed asthma and 29.2% ever physician diagnosed pneumonia. FeNO levels were associated with current wheeze (P = 0.04) and ever physician diagnosed pneumonia (P = 0.05). The mean indoor concentrations were particulate matter with a diameter of <2.5 pm (PM2,5) 268 mu g/m(3), sulfur dioxide (SO2) 40.5 mu g/m(3), nitrogen dioxide (NO2) 43.0 pg/m(3) and CO2 827 parts per million. Outdoor concentrations were PM2.5 244 mu g,/m(3), SO2 106.6 mu g/m(3) and NO2 40.9 pg/m(4). PM2,5 levels inside (P= 0.002) and outside DCCs (P = 0.05) were associated with FeNO levels.

    CONCLUSION: PM2.5 levels inside and outside DCCs in China can contribute to airway inflammation in preschool children. Children with current wheeze and ever physician-diagnosed pneumonia may have higher FeNO levels.

  • 1167846. Zhang, X.
    et al.
    Källne, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Gorini, G.
    Nocente, M.
    Fan, T.
    Yuan, X.
    Xie, X.
    Chen, Z.
    Second generation fusion neutron time-of-flight spectrometer at optimized rate for fully digital data acquisition2014In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 85, no 4, p. 043503-Article in journal (Refereed)
    Abstract [en]

    The progress on high-rate event recording of data is taken as starting point to revisit the design of fusion neutron spectrometers based on the TOF (time-of-flight) technique. The study performed was aimed at how such instruments for optimized rate (TOFOR) can be further developed to enhance the plasma diagnostic capabilities based on measurement of the 2.5 MeV dd neutron emission from D plasmas, especially the weak spectral components that depend on discrimination of extraneous events. This paper describes a design (TOFOR II) adapted for use with digital wave form recording of all detector pulses providing information on both amplitude (pulse height) and timing. The results of simulations are presented and the performance enhancement is assessed in comparison to the present.

  • 1167847. Zhang, X. L.
    et al.
    Shao, L. Y.
    Yu, Z. W.
    Cheng, D. R.
    Jin, R. X.
    He, Sailing
    KTH, Superseded Departments, Electromagnetic Theory.
    Automatic real-time control for gain-flattened fiber Raman amplifiers2004In: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 239, no 01-3, p. 79-84Article in journal (Refereed)
    Abstract [en]

    An automatic control algorithm for flattening the gain of a fiber Raman amplifier is derived from the Raman scattering equations. A pseudo-inverse gain matrix is introduced to adjust the powers of the pump lasers. The algorithm is simple, fast, effective, robust and insensitive to the length and type of the fiber. It is demonstrated experimentally that the gain flattening for Raman amplifiers comprising various types and lengths of fiber and with different target gains can be achieved automatically with this algorithm. The algorithm converges for both small and large input signal. Flattened Raman gain with a fluctuation less than 0.40 dB over a 50-nm bandwidth for a 50-km SMF or less than 0.20 dB over a 40-nm bandwidth for a 6.6-km dispersion compensated fiber is realized in the experiment.

  • 1167848.
    Zhang, X.
    et al.
    ABB AB, Corporate Research, Västerås, Sweden.
    Lindberg, T.
    Karlstad University, Sweden.
    Xiong, Ning
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    Vyatkin, V.
    Luleå University of Technology, Sweden.
    Mousavi, A.
    Luleå University of Technology, Sweden.
    Cooling Energy Consumption Investigation of Data Center IT Room with Vertical Placed Server2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, p. 2047-2052Article in journal (Refereed)
    Abstract [en]

    As energy consumption by cooling data center IT equipment can be over 40% of total energy consumption, efficient cooling for large data centers is essential for reducing operation costs. Modern data centers are complex systems involving IT facilities, power system, cooling and ventilation systems. In our previous work, literature study was made to investigate available data center energy consumption models; and energy consumption models for data center IT room with distributed air flow control were developed. In this paper, the models are further extended and developed to cover the combined distributed air flow control and vertical placed servers in raised floor ventilation system. Simulation of the three types of ventilation systems with Even load, Idle server and Uneven load scenarios showed that significant cooling energy consumed by a traditional ventilation system can be saved by applying the proposed new concept and method. 

  • 1167849. Zhang, X. -M
    et al.
    Cao, W. -H
    Yu, X. -X
    Wu, Sihong
    KTH, School of Architecture and the Built Environment (ABE), Land and Water Resources Engineering (moved 20130630).
    Effect of LUCC on runoff regulation in watershed in loess gullied-hilly region of China2009In: Shuili Xuebao/Journal of Hydraulic Engineering, ISSN 0559-9350, Vol. 40, no 6, p. 641-650Article in journal (Refereed)
    Abstract [en]

    By using the measurement technique of dynamic hydrological process and the estimation method of landscape ecology, the effect of LUCC (Land Use-Cover Change) on runoff regulation in the Luoyugou watershed, located at loess gullied-hilly region of China, in the period from 1986 to 2004 was studied. The results show that the impact of LUCC on runoff regulation is significant due to the increase of forest vegetation coverage and terracing of the land on the slopes. The capacity of runoff yield will be reduced due to the optimal adjustment of land use structures and the increase of forest vegetation in any time scales, including single precipitation event, the period of rainfall season and in the whole year. The reduction percentages of average annual runoff coefficient in rich rainfall year, normal rainfall year and poor rainfall year in the latter land use period from 1995 to 2004 are approximately 51%, 85%, 84% respectively comparing with those in the former land use period from 1986 to 1994. Besides, if neglecting the influence of precipitation amount, the predicted runoff coefficient for latter period decreases by about 63% comparing with those in former period. In addition, the impact of LUCC on runoff exhibits seasonal characteristics and the peak flood amount decreases with the optimal adjustment of land use structures. Although the impact of increasing forest vegetation coverage on the capacity of runoff amount is lager than that of changing land use type from slopping farmland to terrace, both measures must be adopted for fulfilling the requirements of land resources sustainable utilization in Loess gullied-hilly region.

  • 1167850. Zhang, X.
    et al.
    Matthaiou, M.
    Coldrey, M.
    Björnson, Emil
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. SUPELEC, France .
    Impact of residual transmit RF impairments on training-based MIMO systems2014In: 2014 IEEE International Conference on Communications, ICC 2014, 2014, p. 4741-4746Conference paper (Refereed)
    Abstract [en]

    Radio-frequency (RF) impairments, that exist intimately in wireless communications systems, can severely degrade the performance of traditional multiple-input multiple-output (MIMO) systems. Although compensation schemes can cancel out part of these RF impairments, there still remains a certain amount of impairments. These residual impairments have fundamental impact on the MIMO system performance. However, most of the previous works have neglected this factor. In this paper, a training-based MIMO system with residual transmit RF impairments (RTRI) is considered. In particular, we derive a new channel estimator for the proposed model, and find that RTRI can create an irreducible estimation error floor. Moreover, we show that, in the presence of RTRI, the optimal training sequence length can be larger than the number of transmit antennas, especially in the low and high signal-to-noise ratio (SNR) regimes. An increase in the proposed approximated achievable rate is also observed by adopting the optimal training sequence length. When the training and data symbol powers are required to be equal, we demonstrate that, at high SNRs, systems with RTRI demand more training, whereas at low SNRs, such demands are nearly the same for all practical levels of RTRI.

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