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Effects of surface charges on phonon properties and thermal conductivity in GaN nanofilms

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Chinese Physics B 2019年第8期28卷 270-275页

作者： Shu-Sen yang yang hou Lin-Li Zhu Department of Engineering Mechanics and Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceZhejiang UniversityHangzhou 310021China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212000China

Surface charges can modify the elastic modulus of nanostructure,leading to the change of the phonon and thermal properties in semiconductor *** this work,the influence of surface charges on the phonon properties and phonon thermal conductivity of GaN nanofilm are quantitatively *** the framework of continuum mechanics,the modified elastic modulus can be derived for the nanofilm with surface *** elastic model is presented to analyze the phonon properties such as the phonon dispersion relation,phonon group velocity,density of states of phonons in nanofilm with the surface *** phonon thermal conductivity of nanofilm can be obtained by considering surface *** simulation results demonstrate that surface charges can significantly change the phonon properties and thermal conductivity in a GaN *** surface charges reduce the phonon energy and phonon group velocity but increase the density of states of *** surface charges can change the size and temperature dependence of phonon thermal conductivity of GaN *** on these theoretical results,one can adjust the phonon properties and temperature/size dependent thermal conductivity in GaN nanofilm by changing the surface charges.

关键词： surface charges GaN nanofilm elastic model phonon properties thermal conductivity

Atomically dispersed dual-metal-site PGM-free electrocatalysts for oxygen reduction reaction:Opportunities and challenges

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SusMat 2022年第5期2卷 569-590页

作者： Xiaoxuan yang Cameron Priest yang hou Gang Wu College of Chemical and Biological Engineering Zhejiang UniversityHangzhouChina Department of Chemical and Biological Engineering University at BuffaloThe State University of New YorkBuffaloNew YorkUSA Institute of Zhejiang University-Quzhou QuzhouChina School of Biological and Chemical Engineering NingboTech UniversityNingboChina

Atomically dispersed and nitrogen coordinated single metal site(MNx,M=Fe,Co,or Mn)moieties embedded in partially graphitized carbon(denoted as M–N–C)are recognized as the most promising platinum group metal-free catalysts for the oxygen reduction reaction(ORR)in proton exchange membrane fuel ***,simply regulating their coordination environments and local structures of single metal sites cannot fundamentally change active site structure,which leads to insufficient activity and stability.A second transition metal can be incorporated to design dual-metal sites,offering a new opportunity to modulate the electronic and geometric structures of M–N–C ***,exploring optimal atomically dispersed dual-metal-site is essential to designing new active sites with enhanced ORR activity,and stability,especially breaking the activity-stability *** review provides a comprehensive analysis of the advances in developing atomically dispersed dual-metal site catalysts for the ORR,including innovative synthesis methods,primary structural configurations,and the mechanisms to promote catalytic *** aim to elucidate the crucial structure–property correlation,emphasizing the inherent electronic and geometric effects of dual metal ***,we discuss the current challenges of dual-metal site catalysts concerning rational design,precise synthesis,and high-fidelity structural characterization.

关键词： dual metal sites electrocatalysis fuel cells oxygen reduction PGM-free catalyst

AC Line Filter Electrochemical Capacitors:Materials,Morphology,and Configuration

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Energy & Environmental Materials 2022年第4期5卷 1060-1083页

作者： Haichao Tang yang Tian Zhongshuai Wu Yujia Zeng yang Wang yang hou Zhizhen Ye Jianguo Lu State Key Laboratory of Silicon Materials Key Laboratory for Biomedical Engineering of Ministry of EducationSchool of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China State Key Laboratory of Catalysis Dalian Institute of Chemical PhysicsChinese Academy of Sciences457 Zhongshan RoadDalian 116023China Dalian National Laboratory for Clean Energy Chinese Academy of Sciences457 Zhongshan RoadDalian 116023China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Key Laboratory of Biomass Chemical Engineering of Ministry of Education College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China Wenzhou Key Laboratory of Novel Optoelectronic and Nano Materials Institute of WenzhouZhejiang UniversityWenzhou 325036China

Recently,more and more supercapacitors(SCs)have been developed as AC line filter capacitors,which are generally named AC line filter electrochemical capacitors(FECs).Compared to traditional bulky aluminum electrolytic capacitors(AECs),FECs have higher capacity and lower space occupancy,which makes them a strong ***,different from the common SCs for energy storage,it is necessary to consider the frequency response of the SCs for AC line filtering,where the contradiction between frequency response and specific capacitance is a *** researchers have proposed different solutions from the perspective of materials,morphology,and configuration for this *** on the above background,in this review,we briefly introduce the principle and parameters of AC line filter electrochemical *** systematically summarize the state-of-the-art progresses of FECs and discuss their possible application and development in the *** development of FECs can greatly promote the planarization,integration,and miniaturization of filter capacitors,and provide a new solution for the utilization of green and unstable energy.

关键词： AC line filtering fast response filter electrochemical capacitors specific capacitance supercapacitors

Co anchored on porphyrinic triazine-based frameworks with excellent biocompatibility for conversion of CO_(2)in H_(2)-mediated microbial electrosynthesis

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Frontiers of Chemical Science and Engineering 2022年第12期16卷 1761-1771页

作者： Folin Liu Shaohua Feng Siyuan Xiu Bin yang yang hou Lecheng Lei Zhongjian Li College of Chemical and Biological Engineering Key Laboratory of Biomass Chemical Engineering of Ministry of EducationZhejiang UniversityHangzhou 310027China Institute of Zhejiang University—Quzhou Quzhou 324000China Academy of Ecological Civilization Zhejiang UniversityHangzhou 310027China

Microbial electrosynthesis is a promising alternative to directly convert CO_(2)into long-chain compounds by coupling inorganic electrocatalysis with biosynthetic ***,problems arose that the conventional electrocatalysts for hydrogen evolution may produce extensive by-products of reactive oxygen species and cause severe metal leaching,both of which induce strong toxicity toward ***,poor stability of electrocatalysts cannot be qualified for long-term *** problems may result in poor biocompatibility between electrocatalysts and *** solve the bottleneck problem,Co anchored on porphyrinic triazine-based frameworks was synthesized as the electrocatalyst for hydrogen evolution and further coupled with Cupriavidus necator *** showed high selectivity for a four-electron pathway of oxygen reduction reaction and low production of reactive oxygen species,owing to the synergistic effect of Co–Nx modulating the charge distribution and adsorption energy of ***,low metal leaching and excellent stability were observed,which may be attributed to low content of Co and the stabilizing effect of ***,the electrocatalyst exhibited excellent ***,the microbial electrosynthesis system equipped with the electrocatalyst successfully converted CO_(2)to poly-β-*** work drew up a novel strategy for enhancing the biocompatibility of electrocatalysts in microbial electrosynthesis system.

关键词： microbial electrosynthesis hydrogen evolution reaction metalloporphyrins biocompatibility CO_(2)conversion

Coordinated Control of Multi-Agent Systems with a Varying-Velocity Leader and Input Saturation

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Communications in Theoretical Physics 2009年第9期52卷 449-456页

作者： PENG Ke SU hou-Sheng yang Yu-Pu Department of Automation Shanghai Jiao Tong University Shanghai 200240 China

In this paper,we investigate a leader-following tracking problem for multi-agent systems with *** propose a distributed bounded protocol for each follower to track a leader whose states may not be *** theoretically prove that each agent can follow the leader with estimable track ***,somenumerical simulations are presented to illustrate our theoretical results.

关键词： consensus coordinated control multi-agent system networked system input saturation switching topology

Integration of supertetrahedral cluster with reduced graphene oxide sheets for enhanced photostability and photoelectrochemical properties

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Science China Chemistry 2013年第4期56卷 423-427页

作者： hou yang WU Tao WANG Le FENG PingYun Department of Chemistry University of California

Supertetrahedral zinc-gallium-tin sulfide cluster modified with reduced graphene oxide protective layer was first synthesized, which exhibited an excellent photoelectrochemical performance and enhanced stability in co... 详细信息

关键词： supertetrahedral cluster OCF-40-ZnGaSnS reduced graphene oxide protective layer photoelectrochemical activity

Changes in glutathione redox cycle during diapause determination and termination in the bivoltine silkworm, Bombyx moil

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Insect Science 2014年第1期21卷 39-46页

作者： Lin-Chuan Zhao Yi-Sheng hou yang-Hu Sima College of Biological and Basic Medicine Sciences Soochow University Suzhou Jiangsu Province China

To explore whether glutathione regulates diapause determination and termina tion in the bivoltine silkworm Bombyx mori, we monitored the changes in glutathione redox cycle in the ovary of both diapanse and nondiapauseegg producers, as well as those in dia pause eggs incubated at different temperatures. The activity ofthioredoxin reductase （TrxR） was detected in ovaries but not in eggs, while neither ovaries nor eggs showed activity of glutathione peroxidase. A lower reduced glutathione/oxidized glutathione （GSH/GSSG） ratio was observed in the ovary of diapauseegg producers, due to weaker reduction of oxidized glutathione （GSSG） to the reduced glutathione （GSH） catalyzed by glutathione reductase （GR） and TrxR. This indicates an oxidative shift in the glutathione redox cy cle during diapause determination. Compared with the 25℃treated diapause eggs, the 5℃treated diapause eggs showed lower GSH/GSSG ratio, a result of stronger oxidation of GSH catalyzed by thioredoxin peroxidase and weaker reduction of GSSG catalyzed by GR. Our study demonstrated the important regulatory role of glutathione in diapause determination and termination of the bivoltine silkworm.

关键词： Bombyx mori determination diapause glutathione redox cycle termination

Vegetation Community Convergence of Pastoralists' Pasture at Different Economic Levels in Desert Steppe

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Journal of Integrative Agriculture 2014年第6期13卷 1165-1170页

作者： YIN Yan-ting REN Ji-zhou hou Xiang-yang College of Pastoral Agriculture Science and Technology Lanzhou University Grassland Research Institute Chinese Academy of Agricultural Sciences

Vegetation characteristics of pastoralist households’ pastures at different economic levels were quantiifed to compare the grassland conditions in Sunite Right Banner, Inner Mongolia, China in 2011 and 2012. The results showed that the heights of Stipa klemenzis and Cleistogenes songorica were similar among economic treatments. And the height of Allium polyrhizm had no signiifcant differences between high-economic-level （HEL） and low-economic-level （LEL） treatments. There were no signiifcant difference among treatments in the canopy cover of C. songorica. The densities of dominant species （S. klemenzis, C. songorica and A. polyrhizm） were signiifcantly similar among treatments. Aboveground community biomass in reference area （CK） was higher than that in other three treatments in 2011, but their biomass showed no signiifcant difference among three economic treatments;for 2012, biomass in HEL was higher than low-economic-level treatment （LEL）, while the biomass in middle-economic-level treatment （MEL） and CK was similar to that in HEL and LEL, respectively. Aboveground biomass of S. klemenzis and C. songorica was similar among treatments in both 2011 and 2012. Biomass of A. polyrhizum had no signiifcant difference between HEL and MEL. households of LEL had rented out excess lands and those of HEL had leased their available lands thus resulting uniform utilization and convergence of pastoralist households’ pastures across all economic levels.

关键词： convergence mental stocking rate pastoralists decision behavior at the household scale

Spin polarization strategy to deploy proton resource over atomic-level metal sites for highly selective CO_(2) electrolysis

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Frontiers of Chemical Science and Engineering 2022年第12期16卷 1772-1781页

作者： Yingjie Zhao Xinyue Wang Xiahan Sang Sixing Zheng Bin yang Lecheng Lei yang hou Zhongjian Li Key Laboratory of Biomass Chemical Engineering of Ministry of Education College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China Institute of Zhejiang University-Quzhou Quzhou 324000China Nanostructure Research Centre Wuhan University of TechnologyWuhan 430070China

Unlocking of the extremely inert C=O bond during electrochemical CO_(2) reduction demands subtle regulation on a key“resource”,protons,necessary for intermediate conversion but also readily trapped in water splitting,which is still challenging for developing efficient single-atom catalysts limited by their structural simplicity usually incompetent to handle this *** of extra functional units should be ***,a proton deployment strategy is demonstrated via“atomic and nanostructured iron(A/N-Fe)pairs”,comprising atomically dispersed iron active centers spin-polarized by nanostructured iron carbide ferromagnets,to boost the critical protonation *** as-designed catalyst displays a broad window(300 mV)for CO selectivity>90%(98%maximum),even outperforming numerous cutting-edge M–N–C *** well-placed control of proton dynamics by A/N-Fe can promote*COOH/*CO formation and simultaneously suppress H2 evolution,benefiting from the magnetic-proximity-induced exchange splitting(spin polarization)that properly adjusts energy levels of the Fe sites’d-shells,and further those of the adsorbed intermediates’antibonding molecular orbitals.

关键词： CO_(2)electrolysis/single-atom catalysts/spin polarization/proton dynamics/in situ IR spectroscopy/kinetic isotope effect