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  • 1158151.
    Wu, Yunyun
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
    Effect of different parameters on the direct reduction processes of natural iron ores from Uganda2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Around 50 million tones hematite iron ores with high iron content at a grade of 68% were found in Muko area of Uganda. Currently, the iron and steel making industry in the country has not yet developed to meet the demand to process the natural ores. Based on the analysis of its composition and mechanical properties, I infer that the natural iron lump ores can charge directly into reduction furnace without any prior treatment, so that the cost of whole process without additional enrichment and sintering will be reduced quite much. Also direct reduction iron (DRI) process use natural gases instead of coals which can greatly reduce the environmental pollution and lower the processes cost. If the raw materials that fit for requirements of majority plants, the seller´s market can get greater control over prices, terms due to the easy and cheap processing. All lump ores were from Butare area which is one occurrence of Muko and named sample A in this work. This research aims to use the lowest cost method to reduce Butare area iron ores and find out the optimum parameters on reduction reactions of Butare iron lump ores, such as flow rate, temperature, size of samples. Base on experiments with different designed parameters, Butare iron lump ores successfully reduced by DR furnace and microstructure was found to be an important parameter that strongly influent reduction degree of Butare iron lump ores.

  • 1158152.
    Wu, Yunzhen
    et al.
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Meng, Yanan
    Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Rare Earth Resource Utilizat, Changchun 130022, Jilin, Peoples R China.;Univ Sci & Technol China, Sch Appl Chem & Engn, Hefei 230026, Anhui, Peoples R China..
    Hou, Jungang
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Cao, Shuyan
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Gao, Zhanming
    Dalian Univ Technol, Inst Energy Sci & Technol, DUT KTH Joint Educ & Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    Wu, Zhijian
    Chinese Acad Sci, Changchun Inst Appl Chem, State Key Lab Rare Earth Resource Utilizat, Changchun 130022, Jilin, Peoples R China..
    Sun, Licheng
    KTH, School of Chemical Science and Engineering (CHE), Centres, Centre of Molecular Devices, CMD. KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry.
    Orienting Active Crystal Planes of New Class Lacunaris Fe2PO5 Polyhedrons for Robust Water Oxidation in Alkaline and Neutral Media2018In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, no 35, article id 1801397Article in journal (Refereed)
    Abstract [en]

    Developing efficient and stable oxygen evolution reaction (OER) electrocatalysts is essential for realizing sustainable energy conversion, such as solar fuels. Although modulating active sites and electron transfer is of great significance to boost electrocatalysis activity, it still remains a big challenge to desirably actualize this goal. Herein, engineering of active sites and electronic framework is implemented via oriented modulation of crystal planes and construction of lacunaris architecture supported by ammonification-elicited simultaneous incorporation of nitrogen and oxygen-defect strategy. The new class porous nitrogen-incorporated Fe2PO5 with oxygen-defect (N-Fe2PO5-x) polyhedron with dominantly exposed {110} reactive facets exhibits superior performance toward water oxidation, achieving current densities of 10 mA cm(-2) at quite low overpotentials of 235 and 315 mV in alkaline and neutral media, respectively. Furthermore, density functional theoretical calculations reveal the energetically favorable {110} planes of lower absorption energy of intermediates and remolding of electronic density framework arising from the ammoniated elicitation process, contributing to excellent OER performance of lacunaris N-Fe2PO5-x polyhedrons. This work may offer a feasible guideline for regulating active sites and electron transfer to develop low-cost and highly efficient OER electrocatalysts in energy conversion systems.

  • 1158153. Wu, Yupeng
    et al.
    Parham, Mirzaei
    Zhang, Xingxing
    Fang, Wenbo
    Thermal and optical analysis of a passive heat recovery and storage system for building skin2016Conference paper (Refereed)
  • 1158154. Wu, Yu-Shu
    et al.
    Zhang, Keni
    Ding, Chris
    Pruess, K.
    Elmroth, Erik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Bodvarsson, G. S.
    An efficient parallel-computing method for modeling nonisothermal multiphase flow and multicomponent transport in porous and fractured media2002In: Advances in Water Resources, ISSN 0309-1708, E-ISSN 1872-9657, Vol. 25, p. 243-261Article in journal (Refereed)
  • 1158155.
    Wu, Yu-Tang
    et al.
    Univ Paris 11, Univ Paris Saclay, Inst Integrat Biol Cell, NanoBioPhoton Nanofret Com,CNRS,CEA, Orsay, France..
    Qiu, Xue
    Univ Paris 11, Univ Paris Saclay, Inst Integrat Biol Cell, NanoBioPhoton Nanofret Com,CNRS,CEA, Orsay, France..
    Lindbo, Sarah
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Protein Science, Protein Technology.
    Susumu, Kimihiro
    US Naval Res Lab, Opt Sci Div, Code 5600, Washington, DC USA.;KeyW Corp, Hanover, MD 21076 USA..
    Medintz, Igor L.
    US Naval Res Lab, Ctr Bio Mol Sci & Engn, Code 6900, Washington, DC USA..
    Hober, Sophia
    KTH, School of Biotechnology (BIO), Centres, Centre for Bioprocess Technology, CBioPT. KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Biotechnology (BIO), Centres, Albanova VinnExcellence Center for Protein Technology, ProNova.
    Hildebrandt, Niko
    Univ Paris 11, Univ Paris Saclay, Inst Integrat Biol Cell, NanoBioPhoton Nanofret Com,CNRS,CEA, Orsay, France..
    Quantum Dot-Based FRET Immunoassay for HER2 Using Ultrasmall Affinity Proteins2018In: Small, ISSN 1613-6810, E-ISSN 1613-6829, Vol. 14, no 35, article id 1802266Article in journal (Refereed)
    Abstract [en]

    Engineered scaffold affinity proteins are used in many biological applications with the aim of replacing natural antibodies. Although their very small sizes are beneficial for multivalent nanoparticle conjugation and efficient Forster resonance energy transfer (FRET), the application of engineered affinity proteins in such nanobiosensing formats has been largely neglected. Here, it is shown that very small (approximate to 6.5 kDa) histidine-tagged albumin-binding domain-derived affinity proteins (ADAPTs) can efficiently self-assemble to zwitterionic ligand-coated quantum dots (QDs). These ADAPT-QD conjugates are significantly smaller than QD-conjugates based on IgG, Fab', or single-domain antibodies. Immediate applicability by the quantification of the human epidermal growth factor receptor 2 (HER2) in serum-containing samples using time-gated Tb-to-QD FRET detection on the clinical benchtop immunoassay analyzer KRYPTOR is demonstrated here. Limits of detection down to 40 x 10(-12)m (approximate to 8 ng mL(-1)) are in a relevant clinical concentration range and outperform previously tested assays with antibodies, antibody fragments, and nanobodies.

  • 1158156.
    Wu, Yuting
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Process-Oriented User Behavior Study Based on Machine Learning2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 1158157. Wu, Yu-Tzu
    et al.
    Beiser, Alexa S.
    Breteler, Monique M. B.
    Fratiglioni, Laura
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Helmer, Catherine
    Hendrie, Hugh C.
    Honda, Hiroyuki
    Ikram, M. Arfan
    Langa, Kenneth M.
    Lobo, Antonio
    Matthews, Fiona E.
    Ohara, Tomoyuki
    Peres, Karine
    Qiu, Chengxuan
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Seshadri, Sudha
    Sjölund, Britt-Marie
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Skoog, Ingmar
    Brayne, Carol
    The changing prevalence and incidence of dementia over time - current evidence2017In: Nature Reviews Neurology, ISSN 1759-4758, E-ISSN 1759-4766, Vol. 13, no 6, p. 327-U79Article, review/survey (Refereed)
    Abstract [en]

    Dementia is an increasing focus for policymakers, civil organizations and multidisciplinary researchers. The most recent descriptive epidemiological research into dementia is enabling investigation into how the prevalence and incidence are changing over time. To establish clear trends, such comparisons need to be founded on population-based studies that use similar diagnostic and research methods consistently over time. This narrative Review synthesizes the findings from 14 studies that investigated trends in dementia prevalence (nine studies) and incidence (five studies) from Sweden, Spain, the UK, the Netherlands, France, the USA, Japan and Nigeria. Besides the Japanese study, these studies indicate stable or declining prevalence and incidence of dementia, and some provide evidence of sex-specific changes. No single risk or protective factor has been identified that fully explains the observed trends, but major societal changes and improvements in living conditions, education and healthcare might have favourably influenced physical, mental and cognitive health throughout an individual's life course, and could be responsible for a reduced risk of dementia in later life. Analytical epidemiological approaches combined with translational neuroscientific research could provide a unique opportunity to explore the neuropathology that underlies changing occurrence of dementia in the general population.

  • 1158158. Wu, Yu-Tzu
    et al.
    Fratiglioni, Laura
    Stockholm University, Faculty of Social Sciences, Aging Research Center (ARC), (together with KI).
    Matthews, Fiona E.
    Lobo, Antonio
    Breteler, Monique M. B.
    Skoog, Ingmar
    Brayne, Carol
    Dementia in western Europe: epidemiological evidence and implications for policy making2016In: Lancet Neurology, ISSN 1474-4422, E-ISSN 1474-4465, Vol. 15, no 1, p. 116-124Article in journal (Refereed)
    Abstract [en]

    Dementia is receiving increasing attention from governments and politicians. Epidemiological research based on western European populations done 20 years ago provided key initial evidence for dementia policy making, but these estimates are now out of date because of changes in life expectancy, living conditions, and health profiles. To assess whether dementia occurrence has changed during the past 20-30 years, investigators of five different studies done in western Europe (Sweden [Stockholm and Gothenburg], the Netherlands [Rotterdam], the UK [England], and Spain [Zaragoza]) have compared dementia occurrence using consistent research methods between two timepoints in well-defined geographical areas. Findings from four of the five studies showed non-significant changes in overall dementia occurrence. The only significant reduction in overall prevalence was found in the study done in the UK, powered and designed explicitly from its outset to detect change across generations (decrease in prevalence of 22%; p=0.003). Findings from the study done in Zaragoza (Spain) showed a significant reduction in dementia prevalence in men (43%; p=0.0002). The studies estimating incidence done in Stockholm and Rotterdam reported non-significant reductions. Such reductions could be the outcomes from earlier population-level investments such as improved education and living conditions, and better prevention and treatment of vascular and chronic conditions. This evidence suggests that attention to optimum health early in life might benefit cognitive health late in life. Policy planning and future research should be balanced across primary (policies reducing risk and increasing cognitive reserve), secondary (early detection and screening), and tertiary (once dementia is present) prevention. Each has their place, but upstream primary prevention has the largest effect on reduction of later dementia occurrence and disability.

  • 1158159. Wu, Z.
    et al.
    Cao, J.
    Mao, Bo
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Wang, Y.
    Semi-SAD: Applying semi-supervised learning to shilling attack detection2011In: RecSys - Proc. ACM Conf. Recomm. Syst., 2011, p. 289-292Conference paper (Refereed)
    Abstract [en]

    Collaborative filtering (CF) based recommender systems are vulnerable to shilling attacks. In some leading e-commerce sites, there exists a large number of unlabeled users, and it is expensive to obtain their identities. Existing research efforts on shilling attack detection fail to exploit these unlabeled users. In this article, Semi-SAD, a new semi-supervised learning based shilling attack detection algorithm is proposed. Semi-SAD is trained with the labeled and unlabeled user profiles using the combination of naïve Bayes classifier and EM-λ, augmented Expectation Maximization (EM). Experiments on MovieLens datasets show that our proposed Semi-SAD is efficient and effective.

  • 1158160. Wu, Z.
    et al.
    Mao, Bo
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    Cao, J.
    MRGIR: Open geographical information retrieval using MapReduce2011In: Proc. - Int. Conf. Geoinformatics, Geoinformatics, 2011Conference paper (Refereed)
    Abstract [en]

    City objects recommendation based on characteristics of users, location, time and weather is a challenging issue in geographical information retrieval (GIR). In the meanwhile, city objects recommendation is a computation-intensive and data-intensive application. Cloud computing has gained significant attention in recent years to process the large volume of data. MapReduce framework is currently a most dominant technology in cloud computing. Augmented User-based Collaborative Filtering (AUCF) algorithm which can effective deal with hybrid variable types is proposed firstly. Then, MapReduce for GIR (MRGIR) is presented and AUCF is implemented within MRGIR as an example. The MRGIR is implemented in Hadoop which is an open source framework for MapReduce. Experimental results shows that with moderate number of map tasks, the execution time of GIR algorithms (i.e., AUCF) can be reduced remarkably.

  • 1158161. Wu, Z.
    et al.
    Milton, Debra L..
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Nybom, P.
    Sjö, A.
    Magnusson, K. E.
    Vibrio cholerae hemagglutinin/protease (HA/protease) causes morphological changes in cultured epithelial cells and perturbs their paracellular barrier function1996In: Microbial Pathogenesis, ISSN 0882-4010, E-ISSN 1096-1208, Vol. 21, no 2, p. 111-123Article in journal (Refereed)
    Abstract [en]

    In this report, we describe the cytotoxic activity of the cholera hemagglutinin/protease (HA/protease). A concentrated protein sample from the 37 degrees C overnight culture supernatant of CVD110, a delta ctxA, delta zot, delta Ace and hlyA::(ctxB mer) mutant of El Tor biotype Ogawa serotype strain E7946 caused morphological changes in cultured MDCK-I epithelial cells and altered their arrangement of filamentous actin (F-actin) and Zonula occludens-associated protein ZO-1. The drastic morphological changes can be inhibited by Zincov, a specific bacterial metalloprotease inhibitor. The cytotoxic fractions of the sample after FPLC gelfiltration fractionation showed two visible protein bands with molecular weights of approximately 34- and 32 kDa. Microsequencing of these two proteins revealed that they were the cholera HA/protease.

  • 1158162.
    Wu, Z
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Nybom, P
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Magnusson, Karl-Eric
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Distinct effects of Vibrio cholerae haemagglutinin/protease on the structure and localization of the tight junction-associated proteins occludin and ZO-12000In: Cellular Microbiology, ISSN 1462-5814, E-ISSN 1462-5822, Vol. 2, no 1, p. 11-17Article in journal (Refereed)
    Abstract [en]

    Vibrio cholerae produces a little-studied cytotoxin, haemagglutinin/protease (HA/P), in addition to several better-characterized enterotoxins, i.e. cholera toxin (CT), zonula occludens toxin (ZOT) and accessory cholera enterotoxin (Ace). We have found recently that HA/P perturbs the barrier function of Mardin-Darby canine kidney epithelial cell line (MDCK-I) by affecting the intercellular tight junctions (TJs) and the F- actin cytoskeleton. In the present study we have assessed more specifically how TJs are affected by HA/P by investigating the cellular localization and biochemical integrity of two well-characterized TJ-associated proteins, occludin and ZO-1. Western blot analysis showed that occludin bands of 66-85 kDa were digested by HA/P to two predominant bands of around 50 kDa and 35 kDa, and that this degradation was greatly attenuated when the specific bacterial metalloproteinase inhibitor Zincov was co-administered. Trypsin, on the other hand, did not degrade occludin when it was applied in the same way, suggesting that the degradation of occludin by HA/P is an early and specific event. The other TJ-associated protein ZO-1 was not degraded by HA/P in parallel experiments, suggesting the selectivity of HA/P-associated protein degradation. Moreover, immunofluorescence labelling and confocal microscopy showed that ZO-1, but not occludin, around cell-cell boundaries was rearranged by HA/P treatment. Since ZO-1 is located on the inside of the plasma membrane and is directly associated with occludin, the results indicate that breakdown of occludin may send signals to ZO-1 that affect its organization and the structure of the F-actin cytoskeleton. Our finding that the zinc-containing metalloprotease of V. cholerae specifically degraded occludin suggests that specific degradation of important host proteins by bacterial zinc-containing metalloproteases may be an important mechanism in microbial pathogenesis.

  • 1158163. Wu, Z.-G.
    et al.
    Chen, Y.
    Lei, X.
    Liu, Kun
    KTH, School of Electrical Engineering (EES), Automatic Control.
    Zhang, H.
    Recent Developments on Time-Delay Neural Networks2015In: Abstract and Applied Analysis, ISSN 1085-3375, E-ISSN 1687-0409, article id 865409Article in journal (Refereed)
  • 1158164. Wu, Zhendong
    et al.
    Hugelius, Gustaf
    Stockholm University, Faculty of Science, Department of Physical Geography. Stanford University, USA.
    Luo, Yiqi
    Smith, Benjamin
    Xia, Jianyang
    Fensholt, Rasmus
    Lehsten, Veiko
    Ahlström, Anders
    Approaching the potential of model-data comparisons of global land carbon storage2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 3367Article in journal (Refereed)
    Abstract [en]

    Carbon storage dynamics in vegetation and soil are determined by the balance of carbon influx and turnover. Estimates of these opposing fluxes differ markedly among different empirical datasets and models leading to uncertainty and divergent trends. To trace the origin of such discrepancies through time and across major biomes and climatic regions, we used a model-data fusion framework. The framework emulates carbon cycling and its component processes in a global dynamic ecosystem model, LPJ-GUESS, and preserves the model-simulated pools and fluxes in space and time. Thus, it allows us to replace simulated carbon influx and turnover with estimates derived from empirical data, bringing together the strength of the model in representing processes, with the richness of observational data informing the estimations. The resulting vegetation and soil carbon storage and global land carbon fluxes were compared to independent empirical datasets. Results show model-data agreement comparable to, or even better than, the agreement between independent empirical datasets. This suggests that only marginal improvement in land carbon cycle simulations can be gained from comparisons of models with current-generation datasets on vegetation and soil carbon. Consequently, we recommend that model skill should be assessed relative to reference data uncertainty in future model evaluation studies.

  • 1158165.
    Wu, Zhengyang
    Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Studies of Vibrio cholerae toxins (zonula occludens toxin and hemagglutinin/protease) and their effects on epithelial cells1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Intestinal epithelium is important for absorption of nutrients and for defense against harmful substances in the gut. The permeability and barrier functions of epithelia are mainly controlled by intercellular tight junctions. Vibrio cholerae, a noninvasive enteropathogen, produces several toxins which affect the intestinal epithelium Besides the hypertoxic cholera toxin (CT), it has also been suggested to produce two other putative enterotoxins, zonula occludens toxin (ZOT) and accessory cholera enterotoxin (Ace). Since the suggested effects ofZOT on the tight junctions have been shown to be reversible, ZOT could be useful for studying the mechanisms of regulation of the tight junctions. The gene encoding ZOT has been cloned and sequenced, but the ZOT protein was not purified or characterized. Therefore, the first task in this Ph. D. study was isolation and characterization of WT. PCR-derived fragments containing zot were cloned into expression vectors. These vectors were then introduced into E. coli or V. cholerae. However, ZOT could only be expressed as insoluble inclusion bodies in E. coli. When extra signal sequences were used to export it, no stable and reproducible ZOT signals could be found. Neither was there any detectable amount of ZOT -protein in culture supematants of V. cholerae. Moreover, no ZOT-specific effects on cultured epithelial cells, i.e. MDCK-I, Caco-2, and HT-29, could be found in the culture supematants of V. cholerae stralu 395, in which the ZOT-activities were initially found.

    On the other hand, a V. cho/erae stralu that did not contalu any of the known enterotoxins showed severe cytotoxic effects on the epithelial cells. Further investigations revealed that the V. cholerae hemagglutinin/protease (HA/P) was the responsible agent. HA/P did not affect the apical microvilli of the cells but caused distinct reorganization of a tight junction-associated protein Z0-1, as well as reanangement of the F-actin cytoskeleton, as studied with confocal microscopy. These cytotoxic effects of HA/P were reduced by endogenous nitric oxide (NO). HA/P could only cause negligible alterations in the lateral diffusion of ganglioside GMI receptors of er on the cell surface, as assessed with fluorescence recovery after photo bleaching (FRAP). However, extended challenge of MDCK-I cells with HA/P inhibited the uptake of CT by the cells.

  • 1158166.
    Wu, Zhenjing
    et al.
    Tianjin Univ, Sch Environm Sci & Technol, Tianjin 300072, Peoples R China..
    You, Shijun
    Tianjin Univ, Sch Environm Sci & Technol, Tianjin 300072, Peoples R China..
    Zhang, Huan
    Tianjin Univ, Sch Environm Sci & Technol, Tianjin 300072, Peoples R China..
    Fan, Man
    Tianjin Univ, Sch Environm Sci & Technol, Tianjin 300072, Peoples R China..
    Zheng, Wandong
    Tianjin Univ, Sch Environm Sci & Technol, Tianjin 300072, Peoples R China..
    Wang, Yaran
    Tianjin Univ, Sch Environm Sci & Technol, Tianjin 300072, Peoples R China..
    Zhang, Yang
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Mathematical Modeling and Performance Analysis of Seawater Heat Exchanger in Closed-Loop Seawater-Source Heat Pump System2019In: Journal of energy engineering, ISSN 0733-9402, E-ISSN 1943-7897, Vol. 145, no 4, article id 04019012Article in journal (Refereed)
    Abstract [en]

    The seawater source heat pump (SWHP) utilizes low-grade energy from seawater to satisfy heating/cooling requirements of coastal buildings. Compared with the open-loop SWHP system, the closed-loop system is more stable and reliable when used in cold regions because the seawater heat exchanger can mitigate icing and corrosion problems. This study established mathematical modeling for the seawater heat exchanger, which was validated by the experimental results, to estimate the heat transfer performance. The thermal performance of the seawater heat exchanger under different operating conditions was predicted, and the effects of several key parameters on thermal resistance were analyzed. The results revealed that the pipe wall thermal resistance of the original heat exchanger was the most important factor limiting the heat transfer. Hence, a cost analysis of the heat exchangers with different pipe materials was conducted, and the steel pipe with anticorrosive coating was proven to be optimal in reducing pipe wall thermal resistance and economy. The findings are useful in designing and optimizing the seawater heat exchanger and promoting the application of ocean thermal energy.

  • 1158167.
    Wu, Zhenzeng
    et al.
    Department of Material Engineering , Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian.
    Chen, Tingjie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Huang, Daobang
    D epartment of Material Engineering , Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian.
    Wang, Wei
    D epartment of Material Engineering , Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian.
    Xie, Yongqun
    D epartment of Material Engineering , Fujian Agriculture and Forestry University, 350002, Fuzhou, Fujian.
    Wan, Hui
    Department of Forest Products, Mississippi State University, P. O. Box 9800, Starkville, MS 39759 - 9820 USA.
    Wang, Xiaodong (Alice)
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Effect of PVDC on the Fire Performance of Ultra-Low Density Fiberboards (ULDFs)2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 4, p. 8653-8663Article in journal (Refereed)
    Abstract [en]

    Poly vinylidene chloride-vinyl chloride emulsions (PVDC) were added as a substitute for chlorinated paraffin (CP) in the preparation of ultra-low density fiberboards (ULDFs). The micromorphology and fire performance of ULDFs were investigated using a scanning electron microscope, limiting oxygen index instrument, and cone calorimeter. The results showed that PVDC specimens were coated with a regularly smooth film, while the distribution of CP inside CP specimens was uneven. The limiting oxygen index increased with the dosage of PVDC, then reached a plateau at 50 mL and 28%, slightly higher than CP specimens (27.3%). The peak of heat release rate, mean heat release rate, mean CO, and total smoke release of PVDC specimens was reduced 43.3%, 13.5%, 38.5%, and 51.5% lower than respective CP specimens, and with nearly the same total heat release (only 0.04 MJ/m2 higher). Thus, PVDC exhibited excellent heat-reducing and smoke-suppressing properties and could replace CP in ULDFs. 

  • 1158168.
    Wu, Zhenzeng
    et al.
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Chen, Tingjie
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Niu, Min
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Cai, Lili
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Xie, Yongqun
    Fujian Agriculture and Forestry University, Fuzhou, China.
    Wang, Alice
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Effect of Boron-Zinc-Aluminum-Silicium Compounds on the Fire Performance of Ultra-Low Density Fiberboards2016In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 11, no 2, p. 5050-5063Article in journal (Refereed)
    Abstract [en]

    B-Zn-Si-Al compounds are modified Si-Al compounds made of sodium silicate, zinc sulfate, borax, and aluminum sulfate. They act as a fire retardant during the preparation of ultra-low density fiberboards (ULDFs). An orthogonal experiment was used to optimize the contents of the four compounds according to the limiting oxygen index. Fourier transform infrared spectroscopy was employed to preliminarily analyze the chemical structure of the compounds. Additionally, a cone calorimeter was used to assess the fire performance of the ULDFs. The results suggested that the optimized solution was made of 27.0 mL of sodium silicate solution, 27.0 mL of aluminum sulfate solution, 3.0 g of zinc sulfate, and 6.5 g of borax, resulting in an oxygen index of 29.5%. The bond Al-O-B was detected at 1397 and 796 cm-1. The Si-O-Zn bonds were detected at 867 cm-1. The heat release rate, total heat release, and total smoke release decreased and the mass residual ratio increased in the sample using the optimal conditions from the orthogonal array design. It was concluded that B-Zn- Si-Al compounds effectively protect fibers from fire.

  • 1158169.
    Wu, Zhenzeng
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Huang, Daobang
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Wang, Wei
    Department of Material Science and Engineering, Fujian Agriculture and Forestry University, Fuzhou.
    Chen, Tingjie
    Department of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian.
    Lin, Ming
    College of Material Engineering, Fujian Agriculture and Forestry University.
    Xie, Yongqun
    College of Material Engineering, Fujian Agricultural and Forestry Universit.
    Niu, Min
    Department of Material Engineering, Fujian Agriculture and Forestry University, Fuzhou, Fujian.
    Wang, Alice
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Wood Science and Engineering.
    Optimization for fire performance of ultra-low density fiberboards using response surface methodology2017In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 12, no 2, p. 3790-3800Article in journal (Refereed)
    Abstract [en]

    The optimization of the process conditions for fire retardant ultra-low density fiberboards (ULDFs) was investigated using response surface methodology (RSM). Three parameters, namely those of Borax-Zinc-Silicate-Aluminum (B-Zn-Si-Al), chlorinated paraffin (CP), and chloride-vinyl chloride emulsions (PVDC) were chosen as variables. The considerably high R2 value (99.98%) indicated the statistical significance of the model. The optimal process conditions for the limiting oxygen index (LOI) were determined by analyzing the response surface's three-dimensional surface plot and contour plot, and by solving the regression model equation with Design Expert software. The Box-Behnken design (BBD) was used to optimize the process conditions, which showed that the most favorable dosages of B-Zn-Si-Al, CP, and PVDC were 800 mL, 46.47 mL, and 35.64 g, respectively. Under the optimized conditions, the maximum LOI was 48.4.

  • 1158170.
    Wu, Zhenzhi
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, Faculty of Science & Engineering. Beijing Institute Technology, Peoples R China.
    Gong, Chen
    Beijing Institute Technology, Peoples R China.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering. Beijing Institute Technology, Peoples R China.
    Computational Complexity Analysis of FEC Decoding on SDR Platforms2017In: Journal of Signal Processing Systems, ISSN 1939-8018, E-ISSN 1939-8115, Vol. 89, no 2, p. 209-224Article in journal (Refereed)
    Abstract [en]

    The computational complexity evaluation is necessary for software defined Forward Error Correction (FEC) decoders. However, currently there are a limited number of literatures concerning on the FEC complexity evaluation using analytical methods. In this paper, three high efficient coding schemes including Turbo, QC-LDPC and Convolutional code (CC) are investigated. The hardware-friendly decoding pseudo-codes are provided with explicit parallel execution and memory access procedure. For each step of the pseudo-codes, the parallelism and the operations in each processing element are given. Based on it the total amount of operations is derived. The comparison of the decoding complexity among these FEC algorithms is presented, and the percentage of each computation step is illustrated. The requirements for attaining the evaluated results and reference hardware platforms are provided. The benchmarks of state-of-the-art SDR platforms are compared with the proposed evaluations. The analytical FEC complexity results are beneficial for the design and optimization of high throughput software defined FEC decoding platforms.

  • 1158171.
    Wu, Zhenzhi
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, The Institute of Technology.
    Flexible Multistandard FEC Processor Design With ASIP Methodology2014In: PROCEEDINGS OF THE 2014 IEEE 25TH INTERNATIONAL CONFERENCE ON APPLICATION-SPECIFIC SYSTEMS, ARCHITECTURES AND PROCESSORS (ASAP 2014), IEEE , 2014, p. 210-218Conference paper (Refereed)
    Abstract [en]

    Designing decoder for forward error correction (FEC) is more and more challenging because of the requirements on simultaneous supporting of various wireless standards within one IC module. The flexibility, silicon cost and throughput efficiency are all necessary to be traded off. In this paper, by using ASIP methodology, software-hardware co-design is introduced to offer sufficient flexibility of FEC decoding. The decoding procedure can be programmable for decoding QC-LDPC, Turbo and Convolutional Codes. Firstly, the common features from all mentioned algorithms and their corresponding datapaths are analyzed and a unified multi-standard datapath is introduced. Based on it, an application specific instruction-set is proposed and an ASIP (Application Specific Instruction-set Processor) for the FEC algorithms is designed. The firmware FEC codes are developed to adapt to standards. Synthesis results show that the proposed FEC processor is 1.54mm(2) under 65nm CMOS process. It offers QC-LDPC decoding for WiMAX, Turbo decoding for 3GPP-LTE, and 64 states Convolutional code (CC) decoding at the throughput of 193 Mbps, 62 Mbps and 60 Mbps respectively under clock frequency of 200 MHz. The proposed ASIP provides programmable high throughput compared to other tri-mode hardware modules.

  • 1158172.
    Wu, Zhenzhi
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering. Beijing Institute Technology, Peoples R China.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering. Beijing Institute Technology, Peoples R China.
    High-Throughput Trellis Processor for Multistandard FEC Decoding2015In: IEEE Transactions on Very Large Scale Integration (vlsi) Systems, ISSN 1063-8210, E-ISSN 1557-9999, Vol. 23, no 12, p. 2757-2767Article in journal (Refereed)
    Abstract [en]

    Trellis codes, including Low-Density Parity-Check (LDPC), turbo, and convolutional code (CC), are widely adopted in advanced wireless standards to offer high-throughput forward error correction (FEC). Designing a multistandard FEC decoder is of great challenge. In this paper, a trellis application specified instruction-set processor (TASIP) is presented for multistandard trellis decoding. A unified forward-backward recursion kernel with an eight-state parallel trellis structure is proposed. Based on the kernel, a datapath for multialgorithm and a shared memory subsystem are introduced. The flexibility and the compatibility are guaranteed by a programmable decoding flow and the trellis decoding instruction set. Synthesis results show that the area consumption is 2.12 mm(2) (65 nm). TASIP provides trimode FEC decoding ability with the throughput of 533, 186, and 225 Mb/s for LDPC, turbo, and 64 states CC under the clock frequency of 200 MHz, which outperforms other trimode proposals both in area efficiency and recursion efficiency. TASIP provides high-throughput decoding for current standards, including 3rd Generation Partnership Project-Long Term Evolution, 802.16e, and 802.11n, with unified architecture and high compatibility.

  • 1158173.
    Wu, Zhenzhi
    et al.
    Beijing Institute Technology, Peoples R China.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Memory Sharing Techniques for Multi-standard High-throughput FEC Decoder2014In: 2014 INTERNATIONAL CONFERENCE ON EMBEDDED COMPUTER SYSTEMS: ARCHITECTURES, MODELING, AND SIMULATION (SAMOS XIV), IEEE , 2014, p. 93-98Conference paper (Refereed)
    Abstract [en]

    Nowadays multi-standard wireless baseband, Convolutional Code (CC), Turbo code and LDPC code are widely applied and need to be integrated within one FEC module. Since memory occupies half or even more area of the decoder, memory sharing techniques for area saving purpose is valuable to consider. In this work, several memory merging techniques are proposed. A non-conflict access technique for merged path metric buffer is proposed. The results show that 41% of total memory bits are saved when integrating three different decoding schemes including CC (802.11a/g/n), LDPC (802.11n and 802.16e) and Turbo (3GPP-LTE). Synthesis result with 65nm process shows that the merged memory blocks consume merely 1.06mm(2) of the chip area.

  • 1158174.
    Wu, Zheying
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Changizi, Sara
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Empirical residual neutron-proton interaction in odd-odd nuclei2016In: PHYSICAL REVIEW C, ISSN 2469-9985, Vol. 93, no 3, article id 034334Article in journal (Refereed)
    Abstract [en]

    Two types of average neutron-proton interaction formulas are compared: In the first type, neutron-proton interactions for even-even and odd-A nuclei extracted from experimental binding energies show a smooth behavior as a function of mass number A and are dominated by the contribution from the symmetry energy. Whereas in the second type large systematic staggering is seen between even-A and odd-A nuclei. This deviation is understood in terms of the additional neutron-proton interaction in odd-odd nuclei relative to the neighboring even-even and odd-A systems. We explore three possible ways to extract this additional interaction from the binding energy difference of neighboring nuclei. The extracted interactions are positive in nearly all cases and show weak dependence on the mass number. The empirical interactions are also compared with theoretical values extracted from recent nuclear mass models where large unexpected fluctuations are seen in certain nuclei. The reproduction of the residual neutron-proton interaction and the correction of those irregular fluctuations can be a good criterion for the refinement of those mass models.

  • 1158175.
    Wu, Zhe-Ying
    et al.
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Qi, Chong
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Wyss, Ramon
    KTH, School of Engineering Sciences (SCI), Physics, Nuclear Physics.
    Liu, Hong-Liang
    Global calculations of microscopic energies and nuclear deformations: Isospin dependence of the spin-orbit coupling2015In: Physical Review C. Nuclear Physics, ISSN 0556-2813, E-ISSN 1089-490X, Vol. 92, no 2, article id 024306Article in journal (Refereed)
    Abstract [en]

    Background: The deviation between different model calculations that may occur when one goes toward regions where the masses are unknown is getting increased attention. This is related to the uncertainties of the different models which may have not been fully understood. Purpose: To explore in detail the effect of the isospin dependence of the spin-orbital force in the Woods-Saxon potential on global binding energy and deformation calculations. Method: The microscopic energies and nuclear deformations of about 1850 even-even nuclei are calculated systematically within the macroscopic-microscopic framework using three Woods-Saxon parametrizations, with different isospin dependencies, which were constructed mainly for nuclear spectroscopy calculations. Calculations are performed in the deformation space (beta(2), gamma, beta(4)). Both the monopole and doubly stretched quadrupole interactions are considered for the pairing channel. Results: The ground-state deformations obtained by the three calculations are quite similar to each other. Large differences are seen mainly in neutron-rich nuclei and in superheavy nuclei. Systematic calculations on the shape-coexisting second minima are also presented. As for the microscopic energies of the ground states, the results are also very close to each other. Only in a few cases the difference is larger than 2 MeV. The total binding energy is estimated by adding the macroscopic energy provided by the usual liquid drop model with its parameters fitted through the least square root and minimax criteria. Calculations are also compared with the results of other macroscopic-microscopic mass models. Conclusions: All the three calculations give similar values for the deformations, microscopic energies, and binding energies of most nuclei. One may expect to have a better understanding of the isospin dependence of the spin-orbital force with more data on proton- and neutron-rich nuclei.

  • 1158176. Wu, ZhiFang
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Li, Jing
    Hua, JianLi
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Tian, He
    Influence of the Auxiliary Acceptor on the Absorption Response and Photovoltaic Performance of Dye-Sensitized Solar Cells2014In: Chemistry - An Asian Journal, ISSN 1861-4728, E-ISSN 1861-471X, Vol. 9, no 12, p. 3549-3557Article in journal (Refereed)
    Abstract [en]

    Three new dyes with a 2-(1,1-dicyanomethylene)rhodanine (IDR-I, -II, -III) electron acceptor as anchor were synthesized and applied to dye-sensitized solar cells. We varied the bridging molecule to fine tune the electronic and optical properties of the dyes. It was demonstrated that incorporation of auxiliary acceptors effectively increased the molar extinction coefficient and extended the absorption spectra to the near-infrared (NIR) region. Introduction of 2,1,3-benzothiadiazole (BTD) improved the performance by nearly 50%. The best performance of the dye-sensitized solar cells (DSSCs) based on IDR-II reached 8.53% (short-circuit current density (J(sc))=16.73mAcm(-2), open-circuit voltage (V-oc)=0.71V, fill factor (FF)=71.26%) at AM1.5 simulated sunlight. However, substitution of BTD with a group that featured the more strongly electron-withdrawing thiadiazolo[3,4-c]pyridine (PT) had a negative effect on the photovoltaic performance, in which IDR-III-based DSSCs showed the lowest efficiency of 4.02%. We speculate that the stronger auxiliary acceptor acts as an electron trap, which might result in fast combination or hamper the electron transfer from donor to acceptor. This inference was confirmed by electrical impedance analysis and theoretical computations. Theoretical analysis indicates that the LUMO of IDR-III is mainly localized at the central acceptor group owing to its strong electron-withdrawing character, which might in turn trap the electron or hamper the electron transfer from donor to acceptor, thereby finally decreasing the efficiency of electron injection into a TiO2 semiconductor. This result inspired us to select moderated auxiliary acceptors to improve the performance in our further study.

  • 1158177. Wu, Zhifang
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Li, Jing
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Hua, Jianli
    Tian, He
    Effect of bridging group configuration on photophysical and photovoltaic performance in dye-sensitized solar cells2015In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 3, no 27, p. 14325-14333Article in journal (Refereed)
    Abstract [en]

    Three new metal-free organic sensitizers with a D-A-p-A configuration based on a triarylamine donor, 2,1,3-benzothiadiazole (BTD) and different pi units have been synthesized. Because a long alkyl side chain has been attached to the thiophene adjacent to BDT, HECA achieves the best performance. Under standard global AM 1.5 solar light conditions, the HECA based-device gives the best conversion efficiency of 9.13% with a J(sc) of 16.14 mA cm(-2), a V-oc of 0.72 V and a FF of 0.77. Although EDCA displays superior optical properties, it does not give the desired results. The device based on EDCA achieves efficiency of 7.37% with a J(sc) of 15.56 mA cm(-2), a V-oc of 0.67 V and a FF of 0.70. EIS analysis confirms the existence of fast recombination in the EDCA system. Further computational analysis indicates that the coplanarity and the very strong affinity to iodine molecules of EDCA may be the origin of the low performance.

  • 1158178. Wu, Zhifang
    et al.
    Li, Xin
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Hua, Jianli
    Tian, He
    Pyrimidine-2-carboxylic Acid as an Electron-Accepting and Anchoring Group for Dye-Sensitized Solar Cells2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 48, p. 26355-26359Article in journal (Refereed)
    Abstract [en]

    We report a new dye (INPA) adopting pyrimidine-2-carboxylic acid as an electron-accepting and anchoring group to be used in dye-sensitized solar cells. IR spectral analysis indicates that the anchoring group may form two coordination bonds with TiO2 and so facilitate the interaction between the anchoring group and TiO2. The INPA-based cell exhibits an overall conversion efficiency of 5.45%, which is considerably higher than that obtained with cyanoacrylic acid commonly used as the electron acceptor.

  • 1158179.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic cell separation,2009Conference paper (Other academic)
  • 1158180.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic devices using flexible organic electronic materials2015In: Handbook of Flexible Organic Electronics: Materials, Manufacturing and Applications / [ed] S LOGOTHETIDIS, London: Woodhead Publishing Limited, 2015, p. 397-412Chapter in book (Refereed)
    Abstract [en]

    Being deformed without any discontinuities, microfluidics-based electronic devices demonstrate great mechanical flexibility. This chapter systematically reviews the development of microfluidics-based electronic devices with examples. In addition, discussions and perspectives on future development are included.

  • 1158181.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Passive and Active Micromixers2009In: Handbook of Micro Reactors: Vol.1: Fundamentals, Operations and Catalysts / [ed] V. Hessel, J.C. Schouten, A. Renken, and J.-I. Yoshida,, Weinheim: Wiley-VCH Verlagsgesellschaft, 2009, 1Chapter in book (Refereed)
  • 1158182.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Surface modification of PDMS in Microfluidic Devices2014In: Concise Encycloppedia of High Performance Silicones / [ed] Atul Tiwari and Mark D Soucek, Salem, Massachusetts: John Wiley & Sons, 2014Chapter in book (Refereed)
    Abstract [en]

    Being one of the most used materials for fabrication of microfluidic devices, Polydimethylsiloxane (PDMS) attracts great attention for years since G M Whitesides’ group introduced soft lithography - a rapid prototyping of microfluidic systems with PDMS, into the scientific community in the early 1990s. Its advantages in both physical and chemical properties promote a lots of micro/nano applications. Great efforts have been put to enhance its ability as well as minimize its drawbacks. In this chapter, kinds of common used methods in PDMS surface modification with their characterization methods and their recent development are introduced and discussed.

  • 1158183.
    Wu, Zhigang
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Tape Transfer Printing for Microfluidic based Stretchable Electronics2015In: ASME IMECE: Material processing of Flexible Electronics, Devices and Sensors, Zhigang WU , 2015Conference paper (Refereed)
    Abstract [en]

    Stretchable electronics offers unsurpassed mechanical compliance on complex or soft surfaces like the human skin and organs. With uncompromised stretchablility, microfluidic processing offers high possibility to make high performance stretchable electronics. Hence, it is very important to find a good solution to make such kind of stretchable electronics.

     

    Here, with a newly introduced tape transfer printing technique, we present here a new direction to pattern liquid alloys on elastic substrates. By rolling printing or atomized spraying of a liquid alloy onto a soft surface with a tape transferred adhesive mask, a universal fabrication process is provided for high quality patterns of liquid conductors in a meter scale. With this tape transfer printing technique, we can print any pattern on the elastic substrate, which can be done the traditional stencil printing. With the developed technology, we present here an integrated radio frequency identify tag, which showed the robustness of the packaged hybrid integrated system when stretched at 50% in 3,000 cycles. Further developed with a multilayer fabrication technique, a microfluidic stretchable wireless power transfer device with an integrated LED was demonstrated, which could survive cycling between 0% and 25% strain over 1,000 times.

     

    Briefly, the process of tape transfer printing of a liquid alloy is summarized here:

    1. 1.     PDMS substrate was prepared on a rigid support and half-cured on a hot plate.
    2. 2.     A mask for patterning liquid alloy was designed and cut by a cut plotter.
    3. 3.     Then gently, the tape mask on the transfer tape was transferred to the as-prepared half-cured PDMS substrate through the laminated transfer tape after removing the unnecessary patterns.
    4. 4.     The liquid alloy was printed with a sponge head roller by rolling it over several times or atomizing printing with an airbrush scanning.
    5. 5.     The printed liquid alloy patterns were ready, by slowly peeling the tape mask off from the substrate.
    6. 6.     With optional integrating rigid components with so-called localized stiff cells, the liquid alloy circuits were encapsulated with a secondary PDMS layer. This processing can be stacked further for a multilayer fabrication.

    This technique is able to pattern high quality, uniform and clear patterns of 500 μm wide lines with lengths near a meter. A microfluidic RFID and wireless power transfer device were successfully demonstrated with excellent mechanical stretchability as well as good performance.

    In conclusion, our work demonstrated a versatile liquid alloy patterning technique on soft substrates based on tape transferred adhesive masking, and deposition of a liquid alloy. Further improvement and optimization of this process technique could offer higher resolution and repeatability, and create new opportunities to introduce advanced functions in conformal devices, intelligent systems on the skin or what could be implanted for man-machine communication.

  • 1158184.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Asymmetrical selective hydrodynamic focusing for high performance particle separation: 1627_FLOW14_ZGWu, pp. 1-22014Conference paper (Other academic)
  • 1158185.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Fast microfluidic particle filtering by dean spreading2008In: International Conference on Miniaturized Systems for Chemistry and Life Sciences μTAS2008, 2008, p. 1441-1443Conference paper (Refereed)
  • 1158186.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic hydrodynamic cell separation2007Conference paper (Refereed)
  • 1158187.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Microfluidic Hydrodynamic Cell Separation: A Review2009In: Micro and Nanosystems, ISSN 1876-4037, Vol. 1, no 3, p. 181-192Article in journal (Refereed)
    Abstract [en]

    Microfluidic continuous cell separation based on hydrodynamic interaction in a microfluidic channel has attracted attention because of its robustness, high throughput and cell viability. This paper systematically gives an overview on recent advances in hydrodynamic particle and cell separation in microfluidic devices. It presents the basic ideas and fluid mechanics for the hydrodynamic interaction of a particle in a microfluidic system. Secondly, different kinds of devices are introduced with detailed descriptions of their mechanisms, designs and performances. Finally, the review addresses some practical issues of microfluidic sorting devices for use in biological or medical studies.

  • 1158188.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Microfluidics for hydrodynamics2008In: Micro System Workshop MSW08, 2008, p. 54-Conference paper (Refereed)
  • 1158189.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Surface modification of PDMS by gradient-induced migration of embedded Pluronic2009In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 9, no 11, p. 1500-1503Article in journal (Refereed)
    Abstract [en]

    We present a simple, flexible, and environmentally friendly approach to modify the PDMS surface by gradient-induced migration of embedded amphiphilic copolymer Pluronic F127 and the hydrophobic interaction between the migrated embedded Pluronic and substrate molecules near the surface. The modified surface is hydrophilic and reduces the nonspecific adsorption of protein significantly.

  • 1158190.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Jeong, Seung Hee
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Microfluidic Stretchable Radio-Frequency Devices2015In: Proceedings of the IEEE, ISSN 0018-9219, E-ISSN 1558-2256, Vol. 103, no 7, p. 1211-1225Article in journal (Refereed)
    Abstract [en]

    Recently, the shrinking of the personal computer market has given a clear signal that it is time to divert our focus from the strategy of miniaturization of transistors to a different strategy with emerging technologies. As a new form of electronics, stretchable electronics has significantly advanced in the past few years by micro/nanofabrication of thin films of traditional stiff and hard materials such as silicon, metals, and ceramics, and especially subsequent transfer process on an elastic substrate. However, such a thin structure often suffers from high resistance that leads to low performance when long structures are required. This is particularly true for antennas in radio-frequency (RF) electronics. By introducing microfluidics into RF electronics, we found out that it was an excellent way to make high-performance stretchable RF electronics. Apart from antennas, the microfluidic approach was also adopted and further developed to various devices with integrated wireless communication. This fusion of microfluidics with RF electronics brings not only a lot of opportunities for researchers as a radically new research field, but also potentially commercial benefits for industry. As a new emerging field, a huge effort, ranging from fundamental science to technology development, is required to realize it. This paper illustrates the fundamentals in processing and relevant applications, and highlights recent advances in microfluidic RF electronics. The authors would like to inspire the electronics community to further exploit the advantages of this approach and accelerate innovations in this field.

  • 1158191.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Wicher, Grzegorz
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Svenningsen, Åsa Fex
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Microfluidic high viability neural cell separation using viscoelastically tuned hydrodynamic spreading2008In: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 10, no 5, p. 631-638Article in journal (Refereed)
    Abstract [en]

    A high viability microfluidic cell separation technique of high throughput was demonstrated based on size difference continuous mode hydrodynamic spreading with viscoelastic tuning. Using water with fluorescent dye as sample fluid and in parallel introducing as elution a viscoelastic biocompatible polymer solution of alginic sodium, the spreading behavior was investigated at different polymer concentrations and flow rates. Particle separation was studied in the same detail for 9.9 mu m and 1.9 mu m latex beads. Using buffered aqueous solutions and further surface treatments to protect from cell adhesion, separation between neuron cells and glial cells from rat's spine cord was demonstrated and compared to the separation of latex particles of 20 and 4.6 mu m sizes. High relative viability (above 90%) of neural cells was demonstrated compared the reference cells of the same batch.

  • 1158192.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Jobs, Magnus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Rydberg, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hemispherical coil electrically small antenna made by stretchable conductors printing and plastic thermoforming2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 2, article id 027004Article in journal (Refereed)
    Abstract [en]

    A production scalable technique is presented to make hemispherical coil antennas by using a stretchable printed silver paste conductor and plastic thermoforming. To ease the fabrication process an unbalanced feed-structure was designed for solderless mounting on conductive materials. The manufactured antenna had a resonance frequency of 2.467 GHz with a reflection coefficient of -33.8 dB. The measured and simulated radiation patterns corresponded to that of monopole structure and the measured efficiency was 40%.

  • 1158193.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Qun Liu, Ai
    Nanyang Technological University, Singapore.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic continuous particle/cell separation via electroosmotic-flow-tuned hydrodynamic spreading2007In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 17, no 10, p. 1992-1999Article in journal (Refereed)
    Abstract [en]

    Among the microfluidic separation methods, hydrodynamic spreading is a simple and high-throughput continuous separation technique based on the difference in size. However, it is difficult to adjust tiny pressure differences accurately in microfluidic devices. In this study, a combination of electroosmotic flow (EOF) and hydrodynamic flow spreading was employed to tune the size separation of particles. A stream with different kinds of particle suspensions was driven co-fluently with a particle-free carrier stream under both mechanical external and electroosmotic pressure in a microchannel. The EOF-tuned hydrodynamic spreading behaviour was investigated experimentally and modelled through an electric equivalent model and numerical simulation. When the magnitudes of the mechanically and electroosmotically induced pressures were similar, the EOF tuning on the pressure-driven flow became significant. Hence, the hydrodynamic spreading could be easily adjusted by a tuned power supply. The separation was studied in more detail with 1.9 and 9.9 µm fluorescent polystyrene particles. Moreover, separation of E. coli and yeast cells was accomplished. In conclusion, this technique has the advantages of good stability of mechanical-pressure-driven flow and precise tuning of the EOF, and provides a robust method for size-based separation of particles and cells.

  • 1158194.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wicher, Grzegorz
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Fex Svenningsen, Åsa
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Separation of neural cells using two-step separation by combination of soft inertial microfluidics and pinched flow fractionation2010Conference paper (Refereed)
  • 1158195.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wicher, Grzegorz
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Fex Svenningsen, Åsa
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Soft inertial microfluidics for neural cell separation2010In: Micronano System Workshop, 2010, p. 43-Conference paper (Refereed)
  • 1158196.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wicher, Grzegorz
    Svenningsen, Asa Fex
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    SEPARATION OF NERVAL CELLS USING TWO-STEP SEPARATION BY COMBINATION OF SOFT INERTIAL MICROFLUIDICS AND PINCHED FLOW FRACTIONATION2010Conference paper (Refereed)
  • 1158197.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Wicher, Grzegorz
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Svenningsen, Åsa Fex
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Microfluidic high viability separation of neural cells2009In: 2009 4TH IEEE INTERNATIONAL CONFERENCE ON NANO/MICRO ENGINEERED AND MOLECULAR SYSTEMS, VOLS 1 AND 2, Shenzhen, CHINA, JAN 05-08, 2009, IEEE , 2009, p. 1079-1083Conference paper (Refereed)
    Abstract [en]

    A novel microfluidic platform is presented for sorting by size dissociated neurons, glia and stem cells from biopsies of the central nerve system. A highly biocompatible aqueous polymer solution was used in hydrodynamic spreading controlled cell separation. Before cell separation, particles were used for demonstration. To verify the results the fractions were studied using flow cytometry. Further, they were cultured and differentiated. The study indicated that the technique is ready for biological study and that it has a high potential for applications in neural cell regeneration therapy.

  • 1158198.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Willing, B.
    Bjerketorp, J.
    Jansson, J.K.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Soft inertial microfluidics for high throughput separation of bacteria from human blood cells2009In: Lab on a Chip, ISSN 1473-0197, E-ISSN 1473-0189, Vol. 9, no 9, p. 1193-1199Article in journal (Refereed)
    Abstract [en]

    We developed a new approach to separate bacteria from human blood cells based on soft inertial force induced migration with flow defined curved and focused sample flow inside a microfluidic device. This approach relies on a combination of an asymmetrical sheath flow and proper channel geometry to generate a soft inertial force on the sample fluid in the curved and focused sample flow segment to deflect larger particles away while the smaller ones are kept on or near the original flow streamline. The curved and focused sample flow and inertial effect   were visualized and verified using a fluorescent dye primed in the   device. First the particle behaviour was studied in detail using 9.9 and 1.0 mu m particles with a polymer-based prototype. The prototype device is compact with an active size of 3 mm(2). The soft inertial   effect and deflection distance were proportional to the fluid Reynolds number (Re) and particle Reynolds number (Re-p), respectively. We successfully demonstrated separation of bacteria (Escherichia coli) from human red blood cells at high cell concentrations (above   10(8)/mL), using a sample flow rate of up to 18 mL/min. This resulted in at least a 300-fold enrichment of bacteria at a wide range of flow rates with a controlled flow spreading. The separated cells were proven to be viable. Proteins from fractions before and after cell separation were analyzed by gel electrophoresis and staining to verify the removal of red blood cell proteins from the bacterial cell fraction. This novel microfluidic process is robust, reproducible, simple to perform, and has a high throughput compared to other cell sorting systems. Microfluidic systems based on these principles could easily be manufactured for clinical laboratory and biomedical applications.

  • 1158199.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Xiaojiao, Sun
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Highly effective surface modification of PDMS by gradient-induced migration of embedded amphiphilic block copolymers2009In: 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences µTAS 2009, 2009, p. -684Conference paper (Refereed)
  • 1158200.
    Wu, Zhigang
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Luoyu Rd 1037, Wuhan 430074, Hubei, Peoples R China.
    Zhang, Shuo
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Luoyu Rd 1037, Wuhan 430074, Hubei, Peoples R China.
    Vorobyev, Alexey
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Gamstedt, E. Kristofer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Mechanics.
    Wu, Kang
    Huazhong Univ Sci & Technol, State Key Lab Digital Mfg Equipment & Technol, Luoyu Rd 1037, Wuhan 430074, Hubei, Peoples R China.
    Guo, Chuanfei
    Southern Univ Sci & Technol, Dept Mat Sci & Engn, Shenzhen 518055, Peoples R China.
    Jeong, Seung Hee
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Seamless modulus gradient structures for highly resilient, stretchable system integration2018In: MATERIALS TODAY PHYSICS, ISSN 2542-5293, Vol. 4, p. 28-35Article in journal (Refereed)
    Abstract [en]

    Hybrid system integration of rigid components into stretchable systems is often necessary when targeting for valuable functions in various scenarios. Among them, (Young's) modulus gradient structures for system integration demonstrate excellent mechanical performance when stretched. However, the mechanical reliability is still limited under large deformation due to the inherent interface between materials of different modulus. Here, a seamless transition between heterogeneous moduli parts made with polydimethylsiloxane (PDMS)-based elastomers is presented for stretchable system integration by simply tuning their modulus via introducing a small amount of an additive into some parts of the substrate. These gradient structures not only provide a high stretchability (similar to 250%) for the overall system, but also improve the resilience of the system (can be stretched up to 50,000 cycles from 0 to 150% global strain) at the same time. The seamless modulus gradient structures provide a simple and effective way of allowing highly resilient and stretchable system integration for various soft intelligent systems.

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