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Negative Temperature Coefficient of Resistivity in Bulk Nanostructured Ag 被引量:1
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作者 Yushuang LIU, Chimei MO+ and Weili CAI (Department of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China) 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2000年第5期521-524,共4页
The change of the temperature coefficient of resistivity (a) with the particle size, dp, and the grain size, dc, in the nanostructured Ag bulk samples was investigated. dp and dc were controlled by heating the nano-Ag... The change of the temperature coefficient of resistivity (a) with the particle size, dp, and the grain size, dc, in the nanostructured Ag bulk samples was investigated. dp and dc were controlled by heating the nano-Ag powders over the temperature range from 393 to 453 K. The electrical resistance measurements of the nanostructured Ag bulk samples obtained by compacting the Ag powders after heat treatments showed a change in the sign of a with dP and dc. When dp and dc are smaller or equal to 18 and 11 nm below room temperature or 20 and 12 nm above room temperature, respectively, the sign of the temperature coefficient of resistivity changes from positive to negative. The negative a arises mainly from the high resistivity induced by the particle interfaces with very lowly ordered or even disordered structure, a large volume fraction of interfaces and impurities existing in the interfaces, and the quantum size effect appearing in the nano-Ag grains. 展开更多
关键词 Negative Temperature Coefficient of resistivity in bulk Nanostructured Ag
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Quantitative trait loci detection of E dwardsiella tarda resistance in Japanese flounder Paralichthys olivaceus using bulked segregant analysis 被引量:4
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作者 王晓夏 徐文腾 +4 位作者 刘洋 王磊 孙何军 王磊 陈松林 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第6期1297-1308,共12页
In recent years, Edwardsiella tarda has become one of the most deadly pathogens of Japanese fl ounder( Paralichthys olivaceus), causing serious annual losses in commercial production. In contrast to the rapid advances... In recent years, Edwardsiella tarda has become one of the most deadly pathogens of Japanese fl ounder( Paralichthys olivaceus), causing serious annual losses in commercial production. In contrast to the rapid advances in the aquaculture of P. o livaceus, the study of E. tarda resistance-related markers has lagged behind, hindering the development of a disease-resistant strain. Thus, a marker-trait association analysis was initiated, combining bulked segregant analysis(BSA) and quantitative trait loci(QTL) mapping. Based on 180 microsatellite loci across all chromosomes, 106 individuals from the F1333(♀: F0768 ×♂: F0915)(Nomenclature rule: F+year+family number) were used to detect simple sequence repeats(SSRs) and QTLs associated with E. tarda resistance. After a genomic scan, three markers(Scaffold 404-21589, Scaffold 404-21594 and Scaffold 270-13812) from the same linkage group(LG)-1 exhibited a signifi cant difference between DNA, pooled/bulked from the resistant and susceptible groups( P <0.001). Therefore, 106 individuals were genotyped using all the SSR markers in LG1 by single marker analysis. Two different analytical models were then employed to detect SSR markers with different levels of signifi cance in LG1, where 17 and 18 SSR markers were identifi ed, respectively. Each model found three resistance-related QTLs by composite interval mapping(CIM). These six QTLs, designated q E1–6, explained 16.0%–89.5% of the phenotypic variance. Two of the QTLs, q E-2 and q E-4, were located at the 66.7 c M region, which was considered a major candidate region for E. tarda resistance. This study will provide valuable data for further investigations of E. tarda resistance genes and facilitate the selective breeding of disease-resistant Japanese fl ounder in the future. 展开更多
关键词 Paralichthys olivaceus Edwardsiella tarda disease resistance simple sequence repeats(SSRs) bulked segregant analysis(BSA) quantitative trait loci(QTL)
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Application of face centred cubic TiB powder as conductive filler for electrically conductive adhesives 被引量:1
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作者 赵健闯 胡建东 +1 位作者 焦东宁 S.TOSTO 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第6期1773-1778,共6页
Face centred cubic(FCC) TiB ceramic powder synthesized by Ti-boronizing method was used as conductive filler to make ceramic electrically conductive adhesives(ECAs) with the polymer matrix.Electrically conductive ... Face centred cubic(FCC) TiB ceramic powder synthesized by Ti-boronizing method was used as conductive filler to make ceramic electrically conductive adhesives(ECAs) with the polymer matrix.Electrically conductive properties of the ceramic ECAs were studied.The bulk electrical resistivity varied with the powder content of the FCC-TiB in ECAs.The FCC-TiB filled ECAs also showed the percolation behavior that usually occurred for the metal-filled ECAs,the percolation threshold was located at the content of 60%FCC-TiB.A minimum value of 0.1 Ω·cm was obtained at a content of 75%FCC-TiB.In order to check the reliability of mechanical property,tensile test was done to measure the shear strength,and the shear strength dropped with increasing the content of FCC-TiB powders.It is about 12.26 MPa at the content of 70%TiB powders.The Cu filled ECAs were also prepared for comparison.The properties of the oxidation resistance of the two ECAs were evaluated.The results show that the ceramic ECAs have excellent oxidation resistance and better stability compared with the Cu filled ECAs. 展开更多
关键词 ceramic powder face centred cubic TIB electrically conductive adhesives bulk resistivity OXIDATION shear strength
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Development of Reproducing Alumina-Magnesia-Carbon Bricks 被引量:3
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作者 LI Xinjian TANG Kun LIU Zhongjiang WANG Yubin 《China's Refractories》 CAS 2007年第3期22-26,共5页
The reproducing alumina-magnesia-carbon bricks were prepared with the dumped bricks as starting materials. The bulk density, apparent porosity, crushing strength, modolus of rupture and slag resistance of the specimen... The reproducing alumina-magnesia-carbon bricks were prepared with the dumped bricks as starting materials. The bulk density, apparent porosity, crushing strength, modolus of rupture and slag resistance of the specimen were analyzed. The results show that the used refractories can be reused and recycled by the right method. The reproducing alumina-magnesia-carbon bricks with better abilities were prepared. 展开更多
关键词 Reproducing alumina-magnesia-carbon brick Recycling and reusing bulk density Modulus of rupture Slag resistance
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Glass-forming Ability and Corrosion Resistance of Zr—Cu—Al—Co Bulk Metallic Glass 被引量:9
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作者 W.Zhou W.P.Weng J.X.Hou 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2016年第4期349-354,共6页
Investigations were carried out to examine the effects of Co addition on the glass-forming ability (GFA) and corrosion resistance of Zr46Cu46AI8 bulk metallic glass in chloride-containing solution. It is found that ... Investigations were carried out to examine the effects of Co addition on the glass-forming ability (GFA) and corrosion resistance of Zr46Cu46AI8 bulk metallic glass in chloride-containing solution. It is found that the GFA of (Zr46Cu46Al8)100-xCox (x = 0, 1, 2, and 4 at.%) alloys reduces with the increase in Co content and correlates well with the parameters, such as the supercooled liquid region width ATx, the reduced glass transition temperature Trg and γ. The corrosion resistance is however found to be enhanced with the in- crease in Co concentration. The addition of Co causes the enrichment of Zr and Al, but depletes Cu in the surface films, which effectively enhances the corrosion potential and lowers the corrosion current density. 展开更多
关键词 bulk metallic glassCo-additionGlass-forming abilityCorrosion resistance
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Conductivity and mechanical properties of conductive adhesive with silver nanowires 被引量:5
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作者 Xing-Shi Li Xiong-Zhi Xiang +1 位作者 Lei Wang Xiao-Jun Bai 《Rare Metals》 SCIE EI CAS CSCD 2018年第3期191-195,共5页
The aim of this study was to develop conductive adhesive using silver nanowires prepared via solvothermal method as conductive fillers and epoxymodified organosilicone resin as matrix resin. Effect of the addition of ... The aim of this study was to develop conductive adhesive using silver nanowires prepared via solvothermal method as conductive fillers and epoxymodified organosilicone resin as matrix resin. Effect of the addition of silver nanowires/flakes on the conductive adhesive's electrical and mechanical properties was investigated. Compared with conventional conductive adhesive with silver flakes fillers, the percolation threshold of conductive adhesive with silver nanowires fillers is 10 % lower approximately. However, further rise of the content of silver nanowires has no obvious influence on improvement of the electrical conductivity of conductive adhesive. Both conductive and mechanical properties of conductive adhesive can be compatible by adding silver nanowires, which traditional silver conductive adhesives cannot reach. 展开更多
关键词 Silver nanowires Conductive filler bulk resistivity Mechanical properties
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A prototype of a high rating MRPC 被引量:1
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作者 王义 王景波 +4 位作者 颜强 李元景 程建平 岳骞 李金 《Chinese Physics C》 SCIE CAS CSCD 2009年第5期374-377,共4页
Six-gap resistive plate chamber (MRPC) prototypes with semiconductive glass electrodes (bulk resistivity ~ 10^10Ω·cm) were studied for suitability in time-of-flight (TOF) applications at high rates. These... Six-gap resistive plate chamber (MRPC) prototypes with semiconductive glass electrodes (bulk resistivity ~ 10^10Ω·cm) were studied for suitability in time-of-flight (TOF) applications at high rates. These studies were performed using a continuous electron beam of 800 MeV at IHEP and an X-ray machine. Time resolutions of about 100 ps and efficiencies larger than 90% were obtained for flux densities up to 28 kHz/cm^2. 展开更多
关键词 MRPC bulk resistivity high rate time resolution
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Exploration of the oxygen transport behavior in non-precious metal catalyst-based cathode catalyst layer for proton exchange membrane fuel cells
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作者 Shiqu CHEN Silei XIANG +5 位作者 Zehao TAN Huiyuan LI Xiaohui YAN Jiewei YIN Shuiyun SHEN Junliang ZHANG 《Frontiers in Energy》 SCIE CSCD 2023年第1期123-133,共11页
High cost has undoubtedly become the biggest obstacle to the commercialization of proton exchange membrane fuel cells(PEMFCs),in which Pt-based catalysts employed in the cathodic catalyst layer(CCL)account for the maj... High cost has undoubtedly become the biggest obstacle to the commercialization of proton exchange membrane fuel cells(PEMFCs),in which Pt-based catalysts employed in the cathodic catalyst layer(CCL)account for the major portion of the cost.Although nonprecious metal catalysts(NPMCs)show appreciable activity and stability in the oxygen reduction reaction(ORR),the performance of fuel cells based on NPMCs remains unsatisfactory compared to those using Pt-based CCL.Therefore,most studies on NPMC-based fuel cells focus on developing highly active catalysts rather than facilitating oxygen transport.In this work,the oxygen transport behavior in CCLs based on highly active Fe-N-C catalysts is comprehensively explored through the elaborate design of two types of membrane electrode structures,one containing low-Pt-based CCL and NPMCbased dummy catalyst layer(DCL)and the other containing only the NPMC-based CCL.Using Zn-N-C based DCLs of different thickness,the bulk oxygen transport resistance at the unit thickness in NPMC-based CCL was quantified via the limiting current method combined with linear fitting analysis.Then,the local and bulk resistances in NPMC-based CCLs were quantified via the limiting current method and scanning electron microscopy,respectively.Results show that the ratios of local and bulk oxygen transport resistances in NPMCbased CCL are 80%and 20%,respectively,and that an enhancement of local oxygen transport is critical to greatly improve the performance of NPMC-based PEMFCs.Furthermore,the activity of active sites per unit in NPMCbased CCLs was determined to be lower than that in the Pt-based CCL,thus explaining worse cell performance of NPMC-based membrane electrode assemblys(MEAs).It is believed that the development of NPMC-based PEMFCs should proceed not only through the design of catalysts with higher activity but also through the improvement of oxygen transport in the CCL. 展开更多
关键词 proton exchange membrane fuel cells(PEMFCs) non-precious metal catalyst(NPMC) cathode catalyst layer(CCL) local and bulk oxygen transport resistance
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