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Analysis of the Influence of Geometrical Parameters on the Performance of a Proton Exchange Membrane Fuel Cell

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Fluid Dynamics & Materials Processing 2024年第1期20卷 219-237页

作者： Guodong Zhang Huifang Tao Da Li kewei Chen Guoxiang Li Shuzhan Bai ke sun School of Energy and Power Engineering Shandong UniversityJinan250061China Sinotruk Jinan Special Purpose Vehicle Co. Ltd.Jinan250117China

A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel *** this study,the influence of two channel design parameters is investigated,namely,the ratio of the channel width to the bipolar plate ridge width(i.e.,the channel ridge ratio)and the channel *** impact of these parameters is evaluated with respect to the flow pattern,the gas composition distribution,the temperature field and the fuel cell output *** results show that a decrease in the channel ridge ratio and an increase in the channel depth can effectively make the distributions of velocity,temperature and concentration more uniform in each channel and improve the output capability of the fuel *** increase in the channel ridge ratio and depth obviously reduces the flow resistance and improves the flow characteristics.

关键词： Hydrogen fuel cell bipolar plate flow channel multiphysics coupling

Impact of effective stress on permeability for carbonate fractured-vuggy rocks

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 942-960页

作者： ke sun Huiqing Liu Juliana Y.Leung Jing Wang Yabin Feng Renjie Liu Zhijiang Kang Yun Zhang State key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China School of Mining&Petroleum Engineering University of AlbertaEdmontonT6G 1H9Canada SINOPEC Petroleum Exploration and Production Research Institute Beijing100083China

To gain insight into the flow mechanisms and stress sensitivity for fractured-vuggy reservoirs,several core models with different structural characteristics were designed and fabricated to investigate the impact of effective stress on permeability for carbonate fractured-vuggy rocks(CFVR).It shows that the permeability performance curves under different pore and confining pressures(*** stress conditions)for the fractured core models and the vuggy core models have similar change *** ranges of permeability variation are significantly wider at high pore pressures,indicating that permeability reduction is the most significant during the early stage of development for fractured-vuggy *** each obtained effective stress coefficient for permeability(ESCP)varies with the changes in confining pressure and pore pressure,the effective stresses for permeability of four representative CFVR show obvious nonlinear characteristics,and the variation ranges of ESCP are all between 0 and ***,a comprehensive ESCP mathematical model considering triple media,including matrix pores,fractures,and dissolved vugs,was *** is proved theoretically that the ESCP of CFVR generally varies between 0 and ***,the regression results showed that the power model ranked highest among the four empirical models mainly applied in stress sensitivity characterization,followed by the logarithmic model,exponential model,and binomial *** concept of“permeability decline rate”was introduced to better evaluate the stress sensitivity performance for CFVR,in which the one-fracture rock is the strongest,followed by the fracture-vug rock and two-horizontalfracture rock;the through-hole rock is the *** general,this study provides a theoretical basis to guide the design of development and adjustment programs for carbonate fractured-vuggy reservoirs.

关键词： Effective stress Permeability Carbonate fractured-vuggy rocks Structure characteristics Stress sensitivity

Illuminating spin-crossover octanuclear metal-organic cages

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Science China Chemistry 2024年第4期67卷 1208-1215页

作者： Zhi-Kun Liu Alyona A.Starikova Yu-Xia Li ke sun Meng Yu Zi-Shuo Yao Jun Tao key Laboratory of Cluster Science of Ministry of Education School of Chemistry and Chemical EngineeringLiangxiang CampusBeijing Institute of TechnologyBeijing 102488China Institute of Physical and Organic Chemistry Southern Federal UniversityRostov-on-Don 344090Russia

Spin-crossover(SCO)materials that reversibly switch between high-and low-spin states have potential for the storage of spin state-relative information,and have gained much attention incorporating secondary physical properties,such as fluorescence and magneto-optical *** this study,we synthesized three octanuclear metal-organic cages(MOCs)using tetraphenylethylene-based luminophores,aldehydes,and Fe^(Ⅱ)salts,by subcomponent self-assembly approach,namely[Fe1]-[Fe3].By controlling the ligand-field strength and guest encapsulation,we finely tuned their SCO *** them,MOC[Fe2]displayed nearly complete SCO behavior in the solid state,which is rare for high-nuclearity *** also demonstrated the coupling of SCO with fluorescence emission in these MOCs by using isostructural Zn^(Ⅱ)complexes([Zn1]-[Zn3])as control experiments,for the first *** calculations revealed the energy-transfer mechanism between fluorophores and SCOactive centers,which emphasizes the significant contribution of d-d transitions in the interplay between the occurrence of SCO and fluorescence emission.

关键词： metal-organic cages spin crossover fluorescence switching materials DFT calculation

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Flexible nanoimprint lithography enables high-throughput manufacturing of bioinspired microstructures on warped substrates for efficient III-nitride optoelectronic devices

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Science Bulletin 2024年第13期69卷 2080-2088页

作者： Siyuan Cui ke sun Zhefu Liao Qianxi Zhou Leonard Jin Conglong Jin Jiahui Hu Kuo-Sheng Wen Sheng Liu Shengjun Zhou Center for Photonics and Semiconductors School of Power and Mechanical EngineeringWuhan UniversityWuhan 430072China The Institute of Technological Sciences Wuhan UniversityWuhan 430072China Department of Mechanical and Mechatronics Engineering University of WaterlooWaterloo ONN2L 3G1Canada Jiangxi SMTC Semiconductor Co. Ltd.Nanchang 330096China

III-nitride materials are of great importance in the development of modern optoelectronics,but they have been limited over years by low light utilization rate and high dislocation densities in heteroepitaxial films grown on foreign substrate with limited refractive index contrast and large lattice ***,we demonstrate a paradigm of high-throughput manufacturing bioinspired microstructures on warped substrates by flexible nanoimprint lithography for promoting the light extraction *** design a flexible nanoimprinting mold of copolymer and a two-step etching process that enable high-efficiency fabrication of nanoimprinted compound-eye-like Al2O3 microstructure(NCAM)and nanoimprinted compound-eye-like SiO_(2)microstructure(NCSM)template,achieving a 6.4-fold increase in throughput and 25%savings in economic costs over stepper projection *** to NCAM template,we find that the NCSM template can not only improve the light extraction capability,but also modulate the morphology of AlN nucleation layer and reduce the formation of misoriented GaN grains on the inclined sidewall of microstructures,which suppresses the dislocations generated during coalescence,resulting in 40%reduction in dislocation *** study provides a low-cost,high-quality,and high-throughput solution for manufacturing microstructures on warped surfaces of III-nitride optoelectronic devices.

关键词： Flexible nanoimprint lithography Bioinspired Micro-and nano-manufacturing III-nitride epitaxy Optoelectronic devices

Experimental Study on Gas Flow Uniformity in a Diesel Particulate Filter Carrier

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Fluid Dynamics & Materials Processing 2024年第1期20卷 193-204页

作者： Zhengyong Wang Jianhua Zhang Guoliang Su Peixing Yang Xiantao Fan Shuzhan Bai ke sun Guihua Wang School of Energy and Power Engineering Shandong UniversityJinan250061China State key Laboratory of Engines Tianjin UniversityTianjin300072China Weichai Power Emission Solutions Technology Company Limited Weifang261043China China·Shandong·YYO Emission Control System Co. Ltd.Liaocheng252100China

A Diesel Particulate Filter(DPF)is a critical device for diesel engine exhaust products *** using active-regeneration purification methods,on the one hand,a spatially irregular gas flow can produce relatively high local temperatures,potentially resulting in damage to the carrier;On the other hand,the internal temperature field can also undergo significant changes contributing to increase this *** study explores the gas flow uniformity in a DPF carrier and the related temperature behavior under drop-to-idle(DTI)condition by means of bench *** is shown that the considered silicon carbide carrier exhibits good flow uniformity,with a temperature deviation of no more than 2%with respect to the same radius measurement point at the outlet during the regeneration *** the DTI test,the temperature is relatively high within r/2 near the outlet end,where the maximum temperature peak occurs,and the maximum radial temperature gradient is located between r/2 and the *** these quantities grow as the soot load increases,thereby making the risk of carrier burnout ***,it is shown that the soot load limit of the silicon carbide DPF can be extended to 11 g/L,which reduces the frequency of active regeneration by approximately 40%compared to a cordierite DPF.

关键词： DPF flow uniformity DTI silicon carbide carrier soot load

Proposing a machine learning approach to analyze and predict basic high-temperature properties of iron ore fines and its factors

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Journal of Iron and Steel Research(International) 2024年第5期31卷 1082-1094页

作者： Qing-ke sun Yao-zu Wang Jian-liang Zhang Zheng-jian Liu Le-le Niu Chang-dong Shan Yun-fei Ma Institute of Artificial Intelligence University of Science and Technology BeijingBeijing100083China School of Intelligence Science and Technology University of Science and Technology BeijingBeijing100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China

The basic high-temperature properties of iron ore play a crucial role in optimizing sintering and ore blending,but the testing process for these properties is complex and has significant lag time,which cannot meet the actual needs of ore blending.A prediction model for the basic high-temperature properties of iron ore fines was thus proposed based on a combination of machine learning algorithms and genetic ***,the prediction accuracy of different machine learning models for the basic high-temperature properties of iron ore fines was ***,a random forest model optimized by genetic algorithms was built,further improving the prediction accuracy of the *** test results show that the random forest model optimized by genetic algorithms has the highest prediction accuracy for the lowest assimilation temperature and liquid phase fluidity of iron ore,with a determination coefficient of 0.903 for the lowest assimilation temperature and 0.927 for the liquid phase fluidity after *** trained model meets the fluctuation requirements of on-site testing and has been successfully applied to actual production on site.

关键词： Iron ore Basic high-temperature property Machine learning Random forest Genetic algorithm

Interpretation of the Standards of Basic Dataset of Chronic Diseases Behavior Risk Factor Surveillance in Adults

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Biomedical and Environmental Sciences 2024年第5期37卷 551-556页

作者： ZHAO Yan Fang ZHANG Mei WEI Wen Qiang sun ke Xin LI Xin Hua WANG Li Min National Center for Chronic and Noncommunicable Disease Control and Prevention(NCNCD) Chinese Center for Disease Control and PreventionBeijing 100050China Cancer Hospital Chinese Academy of Medical SciencesBeijing 100021China Chinese Center for Disease Control and Prevention Beijing 102206China People's Medical Publishing House Beijing 100021China

BACKGROUND China’s Behavioral Risk Factor Surveillance System(BRFSS)originated from the World Bankfunded HealthⅦLoan Project in the 1990s,which conducted behavioral risk factor surveillance in seven cities and one province^([1]).Drawing on the World Health Organization’s(WHO)STEPwise approach to surveillance(STEPs)and the *** Risk Factor Surveillance System(BRFSS)^([2,3]).

关键词： funded Basic originated

Ecological Networks of Allometric Growth,Feeding Behavior and Gut Microbiota in Chinese Alligator Hatchlings

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Asian Herpetological Research 2024年第2期15卷 104-114页

作者： ke sun Wengang LI Guangwei FAN Liuyang YANG Huabin ZHANG Yilin SHU Yongkang ZHOU Genjun TU Song ZHANG Pingsi YI Maliha AYUB Xiaobing WU Tao PAN College of Life Sciences Anhui Normal UniversityWuhu 241000AnhuiChina The Anhui Provincial key Laboratory of Biodiversity Conservation and Ecological Security in the Yangtze River Basin Wuhu 241000AnhuiChina School of Wetland Yancheng Teachers UniversityYancheng 224007JiangsuChina National Long-term Scientific Research Base for Chinese Alligator Artificial Breeding and Protection in Anhui Anhui Research Center for Chinese Alligator ReproductionXuancheng 242034AnhuiChina

Chinese alligator hatchlings in captivity are fragile and have a high mortality rate within first *** body mass gain of reptile animals is closely related to their feeding behavior and gut *** study analyzed the intrinsic factors influencing the allometric growth of Chinese alligator hatchlings based on their body mass gain,feeding behavior,and gut *** information would enhance the health management of Chinese alligator *** was a significant correlation between the total distance moved,the average number of conspecifics nearby,and body mass *** alligator hatchlings with a greater growth rate showed greater activity and more independent behavior during feeding than those with a lower growth ***,after feeding started,some functions of the gut microbiota showed significant relationships with growth rate and feeding *** alligator hatchlings with a greater growth rate showed greater levels of heme biosynthesis than those with a lower growth rate,and feeding activity was inhibited by long-chain fatty acid *** results elucidate the relationships between health,feeding behavior,and the gut microbiota of Chinese alligator *** the intrinsic factors of their health and feeding behavior can improve the health management of Chinese alligator hatchlings in captivity for conservation.

关键词： allometric growth behavior Chinese alligator hatchlings gut microbiota

变调式理论体系探赜——以周文中《变》(Pien)为例

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中国音乐 2024年第1期 170-176页

作者：孙珂上海音乐学院中央音乐学院

变调式是周文中独创的一种新型调式,其结构和运用方面表现出很强的创新性和包容性,在他的创作中有着重要的结构意义并占据主导地位,成为其创作的重要依据。本文以周文中创作中期的代表作品《变》为例进行分析研究,以阐释作曲家如何运用... 详细信息

变调式是周文中独创的一种新型调式,其结构和运用方面表现出很强的创新性和包容性,在他的创作中有着重要的结构意义并占据主导地位,成为其创作的重要依据。本文以周文中创作中期的代表作品《变》为例进行分析研究,以阐释作曲家如何运用变调式形成个人独特的创作风格,从而为我国当代音乐创作多元化的发展提供参考。

关键词：《变》变调式音高结构创新性包容性