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Rare Metals 2011年第4期30卷 408-413页

作者： CHEN Chao GUO Hong chu ke YIN Fazhang ZHANG Ximing HAN Yuanyuan FAN Yeming The General Research Institute of Nonferrous Metals Beijing Beijing 100088 China

The thermal conductivity of diamond/copper composites with bimodal particle sizes was studied. The composites were prepared through pressure infiltration of liquid copper into diamond preforms with a mixture of 40 and 100 pm-size diamonds. The permeability of the preforms with different coarse-to-fine volume ratios of diamonds was investigated. The thermal conductivity of the diamond/copper composites with bimodal size distribution was compared to the theoretical value derived from an analytical model developed by chu. It is predicted that the diamond/copper composites could reach a higher thermal conductivity and their surface roughness could be improved by applying bimodal diamond particle sizes.

关键词： metallic matrix composites thermal conductivity diamonds copper size distribution pressure infiltration

Isolation of a carbon nanohoop with Mobius topology

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Science China Chemistry 2021年第6期64卷 1004-1008页

作者： Zhen-Lin Qiu Dandan Chen Zeying Deng ke-Shan chu Yuan-Zhi Tan Jun Zhu State key Laboratory of Physical Chemistry of Solid Surfaces Collaborative Innovation Center of Chemistry for Energy Materials(iChEM)College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China

Carbon nanohoop,a class of constrained molecular architecture consisting of linked arene units,has attracted considerable interest from both experimental and theoretical chemists due to its synthetic challenge and aesthetic *** fascinating and synthetically challenging species,the Mobius-type molecule,has been attracting the scientific community with its elegant structure and ***,combining two things together,synthesizing a carbon nanohoop with Mobius topology remains more challenging to *** we report a cyclophenylene featuring Mobius strip characterized by X-ray *** calculations reveal that such type of nanohoop is fully conjugated systems with electrons delocalized both inπsextets and the bridging carbon–carbon *** work highlights that the manipulation of phenylene connection in a carbon nanohoop can help obtain more delicate and aesthetic molecular architectures.

关键词： nanohoop cyclophenylene Mobius aromaticity

Effects of boron on the microstructure and thermal properties of Cu/diamond composites prepared by pressure infiltration

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International Journal of Minerals,Metallurgy and Materials 2011年第4期18卷 472-478页

作者： Ye-ming Fan Hong Guo Jun Xu ke chu Xue-xin Zhu Cheng-chang Jia Non-Ferrous Metal Processing Division General Research Institute for Non-ferrous Metals Beijing 100088 China Institute of Powder Metallurgy University of Science and Technology Beijing Beijing 100083 China

Diamond reinforced copper（Cu/diamond） composites were prepared by pressure infiltration for their application in thermal management where both high thermal conductivity and low coefficient of thermal expansion（CTE） are *** were characterized by the microstructure and thermal properties as a function of boron content,which is used for matrix-alloying to increase the interfacial bonding between the diamond and *** obtained composites show high thermal conductivity（660 W/（m·K）） and low CET（7.4×10-6 K-1） due to the formation of the B13C2 layer at the diamond-copper interface,which greatly strengthens the interfacial *** property measurements indicate that in the Cu-B/diamond composites,the thermal conductivity and the CTE show a different variation trend as a function of boron content,which is attributed to the thickness and distribution of the interfacial carbide *** CTE behavior of the present composites can be well described by kerner＇s model,especially for the composites with 0.5wt% B.

关键词： composite materials pressure infiltration thermal conductivity coefficient of thermal expansion

Pressure infiltrated Cu/diamond composites for LED applications

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Rare Metals 2011年第2期30卷 206-210页

作者： FAN Yeming GUO Hong XU Jun chu ke ZHU Xuexin JIA Chengchang YIN Fazhang Nonferrous Metal Processing Division General Research Institute for Nonferrous Metals Beijing 100088 China Institute of Powder Metallurgy University of Science and Technology Beijing Beijing 100083 China

Diamond reinforced copper （Cu/diamond） composites were prepared by a pressure infilla＇ation technique. The composites show a super high conductivity of 713 W.m-1.K-1 in combination with an extremely low coefficient of thermal expansion （CTE） of 7.72 × 10-6 K-1 （25-100℃）, which are achieved by modifying the copper matrix with adding 0.3 wt.% of boron to get a good thermal contact between the matrix and the diamond particles. By adopting a series of postmachining techniques the composites were made into near-net-shape parts, and an electroless silver coating was also successfully plated on the composites. Finally, their potential applications in the thermal management of fight emitting diodes （LED） were illustrated via prototype examples.

关键词： light emitting diodes (LED) metallic matrix composites copper alloys diamond infiltration thermal conductivity

秦岭细鳞鲑仔稚鱼分布模式及其栖息地环境特征

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水生生物学报 2024年第10期48卷 1716-1723页

作者：陶渝镇王丽英黄青峰邓楚可陈凡刚夏继刚重庆师范大学鱼类生态与保护研究中心重庆401331 重庆师范大学生命科学学院进化生理与行为学实验室淡水鱼类资源保护与利用重庆市重点实验室重庆401331 四川律贝生物科技有限公司成都610000

为揭示秦岭细鳞鲑(Brachymystax tsinlingensis)仔稚鱼分布模式及其环境驱动因子,从而推测产卵场并为该物种早期资源保护提供研究基础。研究选取陕西陇县秦岭细鳞鲑国家级自然保护区内蒲峪河及其支流木拉石沟河作为研究样地,并设定100... 详细信息

为揭示秦岭细鳞鲑(Brachymystax tsinlingensis)仔稚鱼分布模式及其环境驱动因子,从而推测产卵场并为该物种早期资源保护提供研究基础。研究选取陕西陇县秦岭细鳞鲑国家级自然保护区内蒲峪河及其支流木拉石沟河作为研究样地,并设定100个样点(2 m×2 m)作为详细抽样调查生境。研究发现:(1)分布在支流的仔稚鱼数量显著多于干流(P<0.05);(2)仔稚鱼种群数量随海拔变化呈先增后降的趋势,在干流与支流的最适分布海拔分别是1460和1446 m;(3)仔稚鱼分布的环境驱动因子在干流与支流不尽相同,干流仔稚鱼数量与流速和青苔数量显著负相关(P<0.05)、与石蛾幼虫数量显著正相关(P<0.05),支流仔稚鱼数量与流速显著负相关(P<0.05)、与蝌蚪和石蛾幼虫数量显著正相关(P<0.05)。研究揭示了秦岭细鳞鲑仔稚鱼分布模式及其栖息地环境特征,并构建了栖息地各类环境驱动因子关系网络热图。研究结果可为秦岭细鳞鲑仔稚鱼种群调研与监测、栖息地适宜性评估、保护及生态修复提供必要且亟需的科学依据。

关键词：仔稚鱼分布模式海拔底质产卵场秦岭细鳞鲑

维普期刊数据库博看期刊

Diet,food availability,and climatic factors drive ranging behavior in white-headed langurs in the limestone forests of Guangxi,southwest China

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Zoological Research 2021年第4期42卷 406-411页

作者： ke-chu Zhang Qi-Hai Zhou Huai-Liang Xu Zhong-Hao Huang College of Life Science Sichuan Agricultural UniversityYa’anSichuan 625014China key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection(Guangxi Normal University) Ministry of EducationGuilinGuangxi 541004China Guangxi key Laboratory of Rare and Endangered Animal Ecology Guangxi Normal UniversityGuilinGuangxi 541004China

Changes in abiotic and biotic factors can affect the efficiency of biological systems in animals,forcing them to adjust their behaviors in response to daily and seasonal *** September 2016 to August 2017,we collected ranging behavior data on four groups of white-headed langurs(Trachypithecus leucocephalus)in the Guangxi Chongzuo White-Headed Langur National Nature Reserve,Guangxi,southwest *** simultaneously analyzed how multiple ecological factors affect langur ranging behavior,which should facilitate our understanding of the potential mechanisms underlying their adaptation to limestone *** showed that langur ranging behavior was significantly affected by diet composition,food availability,and climatic ***,moving time and daily path length increased with the increase in dietary ***,moving time and daily path length were positively associated with the availability of fruit and relative humidity of the forest,and moderately associated with temperature and relative humidity of bare *** study demonstrated that langurs maintain stable moving and feeding times and exhibit a short daily travel distance,likely adopting an energy-conserving behavioral strategy in response to food shortages and high temperatures in the fragmented karst *** results highlight the importance of food availability and temperature in shaping the ranging behavior of these karst-dwelling primates.

关键词： behavior white karst

EXPERIMENTS OF THREE-DIMENSIONAL FLOW STRUCTURE IN BRAIDED RIVERS

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Journal of Hydrodynamics 2009年第2期21卷 228-237页

作者： HUA Zu-lin GU Li chu ke-jian key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes of Ministry of Education College of Environmental Science and Engineering Hohai University Nanjing 210098 China State key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Nanjing210098 China

The braided river is a typical river pattern in nature, but there is a paucity of comprehensive data set describing the three-dimensional flow field in the braided river. A physical model experiment was used to study the flow characteristics in the typical braided river with a mid-bar between two anabranches. In the experiment, two kinds of mid-bar with the ratios of its length to maximal width of 3 and 5 were considered. Moreover, the mid-bar could be moved to adjust the width of two anabranches. The detailed measurements of velocity were conducted using an acoustic Doppler velocimeter over a grid defined throughout the whole braided river region, including the bifurcation, two anabranches and the confluence. In two kinds of mid-bar braided models, a separation zone was observed in the anabranch of the model in which the ratio of length to maximal width of mid-bar is 3, however the separation zone was not found in another model in which the ratio is 5. In addition, the opposite secondary cells were observed at the bend apex of anabranch in two models, and different longitudinal velocity distributions in the entrance region of anabranch account for this opposite flow structure. Finally, turbulent kinetic energy were shown and compared in different situations. The high turbulence occurs at the place with strong shear, especially at the boundary of the separation zone and the high velocity passing flow.

关键词： braided river three-dimensional flow structure secondary flow turbulent kinetic energy

Effect of powder mixing process on the microstructure and thermal conductivity of Al/diamond composites fabricated by spark plasma sintering

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Rare Metals 2010年第1期29卷 86-91页

作者： chu ke, JIA Chengchang, LIANG Xuebing, and CHEN Hui School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China School of Materials Science and Engineering University of Science and Technology Beijing

Two powder mixing processes, mechanical mixing （MM） and mechanical alloying （MA）, were used to prepare mixed Al/diamond powders, which were subsequently consolidated using spark plasma sintering （SPS） to produce bulk Al/diamond composites. The effects of the powder mixing process on the morphologies of the mixed powders, the microstructure and the thermal conductivity of the composites were investigated. The results show that the powder mixing process can significantly affect the microstructure and the thermal conductivity of the composites. Agglomerations of the particles occurred in mixed powders using MM for 30 min, which led to high pore content and weak interfacial bonding in the composites and resulted in low relative density and low thermal conductivity for the composites. Mixed powders of homogeneous distribution of diamond particles could be obtained using MA for 10 min and MM for 2 h. The composite prepared through MA indicated a high relative density but low thermal conductivity due to its defects, such as damaged particles, Fe impurity, and local interfacial debonding, which were mainly introduced in the MA process. In contrast, the composite made by MM for 2 h demonstrated high relative density and an excellent thermal conductivity of 325 W.m^-1.K^-1, owing to its having few defects and strong inter-facial bonding.

关键词： metal matrix composites thermal properties sintering powder mixing

Flow patterns and critical criteria of thermally stratified shear flow in braided rivers

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Water Science and Engineering 2017年第3期10卷 225-235页

作者： Li Gu Qiu-lan Li Bo Dai Zu-lin Hua Xiao-dong Liu ke-jian chu Department of Civil and Environmental Engineering University of AlbertaEdmonton T6G 2R3Canada key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes Ministry of EducationHohai UniversityNanjing 210098China Zhenjiang Urban Planning and Design Institute Zhenjiang 212000China Jiangsu Transportation Institute Nanjing 210098China National Engineering Research Center of Water Resources Efficient Utilization and Engineering Safety Hohai UniversityNanjing 210098China

Flow characteristics of thermally stratified shear flow in braided rivers are particularly complicated and poorly understood. In this study, a series of typical flow patterns was examined and their critical criteria were determined. Four flow patterns were identified: mixed, locally unstable, continuously stratified, and two-layer flow. Temperature distributions of the four types of flow patterns were analyzed and *** critical Froude numbers for unstable flow, FDcr1, and stable flow, FDcr2, were determined to be 6 and 1, respectively, and comparison of FDcr1 and FDcr2 to the peak Froude numbers, FD1 at the outer bank and FD2 at the inner bank along the anabranch, allowed the flow patterns to be assessed. Then, a discriminant based on initial Jeffreys-keulegan stability parameters was established to distinguish the flow stages from twolayer flow to completely mixed flow. It is indicated that the three critical Jeffreys-keulegan parameters increased with the diversion angle of braided rivers. Results also show that, compared to the stratified flow in straight and curved channels, it was more difficult for braided stratified flow to maintain as two-layer flow, and it more easily became mixed flow. Consequently, empirical expressions for stability criteria of the thermally stratified shear flow in braided rivers are presented.

关键词： Braided river Critical criterion Empirical formula Flow pattern Temperature distribution Thermally stratified flow

Mesoscale Moist Adjoint Sensitivity Study of a Mei-yu Heavy Rainfall Event

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Advances in Atmospheric Sciences 2010年第6期27卷 1415-1424页

作者：储可宽谈哲敏 key Lab of Mesoscale Severe Weather/MOE and School of Atmospheric SciencesNanjing University

The mesoscale moist adjoint sensitivities related to the initiation of mesoscale convective systems （MCSs） are evaluated for a mei-yu heavy rainfall event. The sensitivities were calculated on a realistic background gained from a four-dimensional variational data assimilation of precipitation experiment to make the sensitivity computation possible and reasonable within a strong moist convective event at the mesoscale. The results show that the computed sensitivities at the mesoscale were capable of capturing the factors affecting MCS initiation. The sensitivities to the initial temperature and moisture are enhanced greatly by diabatic processes, especially at lower levels, and these sensitivities are much larger than those stemming from the horizontal winds, which implies that initiation of MCSs is more sensitive to low-level temperature and moisture perturbations rather than the horizontal winds. Moreover, concentration of sensitivities at low levels reflects the characteristics of the mei-yu front. The results provide some hints about how to improve quantitative precipitation forecasts of mei-yu heavy rainfall, such as by conducting mesoscale targetted observations via the adjoint-based method to reduce the low-level errors in the initial temperature and moisture.

关键词： adjoint sensitivity analysis mei-yu heavy rainfall mesoscale