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Influence of sintering temperature on the phases and photoelectric characteristics of BiOCl/ZnO composite powders

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International Journal of Minerals,Metallurgy and Materials 2017年第12期24卷 1438-1447页

作者： Song chen De-gui Zhu School of Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China

Zinc oxide is a typical functional oxide that has been widely researched for various industry applications due to its peculiar physical characteristics. However, to achieve its potential in promising applications, much work has been diligently performed to improve the physical properties of ZnO. In this work, an aqueous suspension route was used to prepare BiOCl/ZnO composite powders, and sintering processes were applied to investigate the influence of sintering temperature on the phase evolutions, microstructures, and photoelectric characteristics of BiOCl/ZnO composite powders. The results indicated that the photoelectric properties mainly depend on the relevant content of BiOCl in the composite powders and the sintering temperature. The photoelectric measurements in K_2SO_4 solutions show that the photoelectric properties of the samples with the appropriate BiOCl content(0.3 mol% and 2.0 mol%) are better than those of ZnO and commercial TiO_2(P_(25)) powders, but the photoelectric measurements in NaOH solutions indicate that the photoelectric characteristics of the as-sintered samples are only better than those of P_(25).

关键词： ZnO/BiOCl composites sintering temperature microstructures photoelectric characteristics

Investigation of flexible electrodes modified by TiN,Pt black and IrO_x

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Science China(Technological Sciences) 2011年第9期54卷 2305-2309页

作者： LI XiaoQian PEI WeiHua TANG RongYu gui qiang GUO Kai WANG Yu chen HongDa State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences BeOing 100083 China School of Physical Science and Technology LanZhou University Lanzhou 730000 China

TiN, platinum （Pt） black and iridium oxide are introduced to the stimulating sites to improve the performance of the flexible electrode. Low temperature process is used to fabricate the modifying films. TiN is coated on the gold sites by magnetron sputtering while platinum black and iridium oxide are coated by electroplating and electrodeposifion, respectively. The impedance of the electrode decreases dramatically after modification. The combined analysis of surface morphology and cyclic voltammograms （CV） in phosphate buffer saline （PBS） solution indicates that the modified electrode sites have larger electrode-electrolyte capacitance and smaller faradic resistance than unmodified sites, thus they have smaller electrochemical impedances.

关键词： flexible electrodes modification impedance cyclic voltammograms (CV)

Fabrication and characterization of implantable silicon neural probe with microfluidic channels

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Science China(Technological Sciences) 2012年第1期55卷 1-5页

作者： GUO Kai PEI WeiHua LI XiaoQian gui qiang TANG RongYu LIU Jian chen HongDa State Key Laboratory on Integrated Optoelectronics Institute of Semiconductors Chinese Academy of Sciences Beijing 100083 China

In this paper, a silicon-based neural probe with microfluidic channels was developed and evaluated. The probe can deliver chemicals or drugs to the target neurons while simultaneously recording the electrical action of these neurons extracellularly. The probe was fabricated by double-sided deep reactive ion etching （DRIE） from a silicon-on-insulator （SO1） wafer. The flu- idic channels were formed with V-shape groove etching on the silicon probe and sealed with silicon nitride and parylene-C. The shank of the probe is 4 mm long and 120 ~tm wide. The thickness of the probe is 100 ~tm. The probe has two fluidic chan- nels and two recording sites. The microfluidic channels can withstand a pressure drop as much as 30 kPa and the flow resisti ity of the microfluidic channel is 0.13 μL min-1 kPa-1, The typical impedance of the neural electrode is 32.3 kΩ at 1 kHz at room temperature.

关键词： neural probe parylene-C microfluidic channel

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台风“暹芭”对湖南影响的分阶段对比分析

灾害学 2025年第1期40卷 102-109页

作者：唐明晖陈龙赵恩榕王强陈紫妍湖南省气象台湖南长沙410118 气象防灾减灾湖南省重点实验室湖南长沙410118 洞庭湖国家气候观象台湖南岳阳414000 怀化市气象局湖南怀化418000

利用常规观测、再分析和双偏振雷达资料,结合拉格朗日混合单粒子轨迹模式(HYSPLIT),对比分析了2022年台风“暹芭”影响湖南的三个阶段(台前飑线、台风倒槽、台风低压)水汽来源、双偏振特征,并探讨降水特征。结果表明:①台前飑线阶段,水... 详细信息

利用常规观测、再分析和双偏振雷达资料,结合拉格朗日混合单粒子轨迹模式(HYSPLIT),对比分析了2022年台风“暹芭”影响湖南的三个阶段(台前飑线、台风倒槽、台风低压)水汽来源、双偏振特征,并探讨降水特征。结果表明:①台前飑线阶段,水汽主要源自西太平洋、鄱阳湖,沿东风输送至湘北,与东北风形成辐合;回波表现为积云降水特征,呈带状、质心偏低;Z_(DR)和K_(DP)值高,CC值大,以数浓度高扁平大雨滴为主。②台风倒槽阶段,水汽源自南海和西太平洋,沿槽前偏东南气流向湘中输送;回波表现为层云降水特征,低层Z_(H)、K_(DP)、Z_(DR)偏低,CC偏大,以数浓度低的小雨滴为主;5 km高度出现CC亮带,导致“列车效应”暴雨。③台风低压阶段,水汽源自中南半岛、北部湾和南海,沿低压向湘东南、湘东北输送;回波呈积层混合降水特征,中低层K_(DP)有大值(≥1.7°/km)区,Z_(DR)强度偏弱,以数浓度高小雨滴为主。研究结果有助于理解台风影响下的降水特征。

关键词：台风“暹芭” 分阶段分析水汽输送台前飑线雷达双偏振

High Electrical and Thermal Conductivity of Nano-Ag Paste for Power Electronic Applications

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Acta Metallurgica Sinica(English Letters) 2020年第11期33卷 1543-1555页

作者： Hong-qiang Zhang Hai-Lin Bai qiang Jia Wei Guo Lei Liu gui-Sheng Zou School of Mechanical Engineering and Automation.Beihang University Beijing 100191China Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China

The nano-Ag paste consisted of Ag nanoparticles and organic *** organics would be removed by evaporation or decomposition during *** the sintering temperature was 300℃,the resistivity of sintered bulk was 8.35×10^-6Ωcm,and its thermal conductivity was 247 W m^-1 K^-*** Si/SiC chips and direct bonding copper(DBC)substrates could be bonded by this nano-Ag paste at low *** bonding interface,sintered microstructure and shear strength of Si/SiC chip attachment were investigated by scanning electron microscopy,transmission electron microscopy and shear *** showed that the sintered Ag layer was porous structure and tightly adhered to the electroless nickel immersion gold surface of DBC substrate and formed the continuous Ag–Au interdiffusion *** shear strength of Si and SiC chip attachments was higher than 35 MPa when the sintering pressure was 10 *** fracture occurred inside the sintered Ag layer,and the fracture surface had obvious plastic deformation.

关键词： Nano-Ag paste Sintering process Interfacial microstructure Chip attachment Shear strength

Dedication on the Occasion of Professor Xiaqi Ding's 80th Birthday

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Acta Mathematicae Applicatae Sinica 2008年第3期24卷 353-354页

作者： Dao-min Cao gui-qiang chen Yan-yan Li Xi-ping Zhu Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China Department of Mathematics Northwestern University Evanston USA Department of Mathematics Rutgers University Piscataway NJ 08854 USA Department of Mathematics Zhongshan University Guangzhou 510275 China

This volume is dedicated to Professor Xiaqi Ding, an academician of the Chinese Academy of Sciences, on the occasion of his eightieth birthday.

关键词： Professor Xiaqi Ding's 80th birthday Chinese Academy of Sciences

Crystalline Morphology and Crystallization Characteristics of In-situ Blends of Anionic Polyamide 6 with Noncrystallizable Semiaromatic Polyamide Copolymer

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Chemical Research in Chinese Universities 2007年第3期23卷 360-365页

作者： WANG Xiao-chun ZHENG qiang YANG gui-sheng Department of Polymer Science and Engineering Zhejiang University Hangzhou 310027 P. R. China Key Laboratory of Macromolecular Synthesis and Functionalization Ministry of Education Hangzhou 310027 P. R. China Key Laboratory＇of Engineering Plastics Institute of Chemistry Chinese Academy of Sciences Beijing 100080 P. R. China

A noncrystallizable semiaromatic polyamide copolymer（NSAP） was dissolved in molten caprolactam, and PA6/ NSAP blends were produced in-situ via the anionic ring-opening polymerization of caprolactam. The presence of a single loss tangent（tanS） peak measured by means of dynamic mechanical analysis（DMA） proves the miscibility between PA6 and NSAP in the blends. It was found that there existed drastic changes in the crystallographic form and crystallization kinetics for the in-situ blends, e.g. , when 20% NSAP was added, nearly all crystallites existed in the ,y form and the crystallization could hardly occur upon cooling even at a rate of 2.5 ℃/min. Moreover, cold crystallization appears during the subsequent heating, and its melting point is 40 ℃ lower than that of the virgin system. On the other hand, the size of the spherulites only decreases modestly. It is suggested that the introduction of irregular stiff segments originated from NSAP into PA6 macromolecule chain, which resulted from transamidation during the polymerization play a dominant role in the drastic change of crystallization kinetics and the resultant morphology of the in-situ blends.

关键词： In-situ blend Noncrystallizable polyamide copelymer Anionic polymerization Morphology Crystallization

Achieving strength-ductility synergy in a non-equiatomic Cr_(10)Co_(30)Fe_(30)Ni_(30)high-entropy alloy with heterogeneous grain structures

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Rare Metals 2022年第8期41卷 2864-2876页

作者： chen-Liang Chu Wei-Ping chen Jun-chen Liu qiang chen Zhi-qiang Fu Guangdong Key Laboratory for Advanced Metallic Materials Processing South China University of TechnologyGuangzhou510641China Southwest Technology and Engineering Research Institute Chongqing400039China

Cold rolling and post-deformation annealing(PDA)heat treatments were used to produce heterogeneous grain structures(HGS)in a single-phase face-centered cubic(fcc)Cr_(10)Co_(30)Fe_(30)Ni_(30)high-entropy alloy(HEA).The microstructural evolution and microstructure-property relationship of the HEA were systematically studied under different *** could be achieved in PDA-treated samples at 875℃for 20 s and at 900℃for 20 s(PDA-900-20 s).PDA-900-20 s sample exhibits the most excellent combination of strength and ductility,showing a tensile yield strength of~590 MPa,an ultimate strength of~706 MPa and a total elongation of~23.9%.Additionally,compared with the homogenized counterpart exhibiting homogenous grains,PDA-900-20 s sample displays a notable increment of~413%in yield strength and simultaneously maintains a good *** dominated strengthening mechanisms in PDA-900-20 s sample are grain-boundary strengthening and heterogeneous deformation-induced(HDI)strengthening,whereas the good ductility is mainly resulted from the HDI ***,the present study provides an effective and simple pathway to overcome the strength-ductility tradeoff of typical fcc HEAs through heterogeneous microstructure.

关键词： High-entropy alloy Heterogeneous grain structures Hetero-deformation-induced hardening Mechanical properties Strengthening mechanism

PARALLEL COMPOUND METHODS FOR SOLVING PARTITIONED STIFF SYSTEMS

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Journal of Computational Mathematics 2001年第6期19卷 639-650页

作者： Li-rong chen De-gui Liu Beijing Inst Comp Applicat & Simulat Technol Beijing 100854 Peoples R China

Deals with the solution of partitioned systems of nonlinear stiff differential equations. Discussion on parallel compound methods; Nonstiff equations; Order conditions of the parallel compound methods (PCM); Numerical... 详细信息

关键词： parallel compound methods stiff systems order conditions convergence stability