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Science China mathematics 2016年第4期59卷 809-822页

作者： wei Qingm.ng School of mathematics and Statistics Northeast Normal University

In this paper,we consider an optimal control problem with state constraints,where the control system is described by a mean-field forward-backward stochastic differential equation(mFFBSDE,for short)and the admissible control is mean-field *** full use of the backward stochastic differential equation theory,we transform the original control system into an equivalent backward form,i.e.,the equations in the control system are all *** addition,Ekeland's variational principle helps us deal with the state constraints so that we get a stochastic maximum principle which characterizes the necessary condition of the optimal *** also study a stochastic linear quadratic control problem with state constraints.

关键词： mean-field forward-backward stochastic differential equations maximum principle state constraints

A Gauss-Bonnet-Chern theorem for complex Finsler m.nifolds

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Science China mathematics 2016年第3期59卷 515-530页

作者： ZHAO wei Departm.nt of mathematics East China University of Science and Technology

Using Chern's method of transgression and the currents, we establish a Gauss-Bonnet-Chern theorem for general closed complex Finsler m.nifolds(m, F). This result extends the classical Gauss-Bonnet-Chern theorem for Hermitian m.nifolds. Furthermore, a simplified version of the Gauss-Bonnet-Chern theorem is obtained in the case of complex Berwald 1-m.nifolds.

关键词： complex Finsler m.nifold the Gauss-Bonnet-Chern theorem transgression method

COnVERGEnCE AnD STABILITY OF THE SPLIT-STEP THETA mETHOD FOR A CLASS OF STOCHASTIC VOLTERRA InTEGRO-DIFFEREnTIAL EQUATIOnS DRIVEn BY LEVY nOISE

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Journal of Computational mathematics 2024年第6期42卷 1688-1713页

作者： wei Zhang School of mathematical Sciences Heilongjiang UniversityHarbinChina

In this paper,we investigate the theoretical and numerical analysis of the stochastic Volterra integro-differential equations(SVIDEs)driven by L´evy *** existence,uniqueness,boundedness and mean square exponential stability of the analytic solutions for SVIDEs driven by L´evy noise are *** split-step theta method of SVIDEs driven by L´evy noise is *** boundedness of the numerical solution and strong convergence are ***,its mean square exponential stability is *** numerical examples are given to support the theoretical results.

关键词： Stochastic Volterra integro-differential equations Existence and uniqueness Stability Split-step theta method Convergence

Catalytic decomposition of methane to produce hydrogen:A review

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Journal of Energy Chemistry 2021年第7期30卷 415-430页

作者： Zeyu Fan wei Weng Jing Zhou Dong Gu wei Xiao School of Resource and Environm.ntal Sciences Hubei International Scientiﬁc and Technological Cooperation Base of Sustainable Resource and EnergyWuhan UniversityWuhan 430072HubeiChina College of Chemistry and molecular Sciences Hubei Key Laboratory of Electrochemical Power SourcesWuhan UniversityWuhan 430072HubeiChina The Institute for Advanced Studies Wuhan UniversityWuhan 430072HubeiChina

The increasing dem.nds of hydrogen and the recent discovery of large reserves of methane have prompted the conversion of methane to *** challenges raised by intensive CO_(2) emission from the traditional conversion of methane have provoked emission-free hydrogen production from *** catalytic decomposition of methane(CDm) to produce hydrogen and advanced carbon hence comes into consideration due to the short process and environm.ntal *** m.ny researchers have made considerable progress in CDm research on the laboratory scale,CDm is still in its infancy in *** history of its developm.nt,fundam.ntal mechanisms,and recent research progress in catalysts and catalytic systems are herein *** problems of catalytic interface degradation are reviewed,focusing on deactivation from coke deposition in the CDm *** introduction of a liquid phase interface which can in-situ remove carbon products provides a new strategy for this ***,the challenges and prospects for future research into novel CDm catalysts or catalyst systems are included.

关键词： Hydrogen production methane decomposition metal-based catalysts Carbon-based catalysts Liquid catalyst

Effects of K and mn promoters over Fe2O3 on Fischer–Tropsch synthesis

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Journal of Energy Chemistry 2020年第8期29卷 118-127,I0004页

作者： Teng Lv wei Weng Jing Zhou Dong Gu wei Xiao School of Resource and Environm.ntal Sciences Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and EnergyWuhan UniversityWuhan 430072HubeiChina The Institute for Advanced Studies Wuhan UniversityWuhan 430072.HubeiChina

Structural and compositional design of core-shell structure is an effective strategy towards enhanced ***,amorphous mnO2 nanosheets and K+-intercalated layered mnO2 nanosheets are controllably assembled over Fe2O3 spindles,in which the mnO2 nanosheets are perpendicularly anchored to the surface of *** a core shell structure contributes to a high specific surface area and abundant pore channels on the surface of *** addition,the existence of K+provides large numbers of basic sites and restrains the formation of unpleasant(Fe1-xmnx)*** from the merits in structure and composition,CO adsorption is enhanced and remaining time of intermediates is prolonged on the surfaces of catalysts during the Fischer–Tropsch synthesis(FTS),facilitating to the formation of active iron carbides and C–C coupling ***,the Fe2O3@K+-mn O2 shows both a high CO conversion of 82.3%and a high C5+ selectivity of 73.1%.The present study provides structural and compositional rationales on design high-perform.nce catalysts towards FTS.

关键词： Fischer–Tropsch synthesis K promoter mn promoter CO conversion C5+selectivity

Interfacial confinem.nt of ni-V2O3 in molten salts for enhanced electrocatalytic hydrogen evolution

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Journal of Energy Chemistry 2020年第11期29卷 280-285页

作者： Jing Zhou Hansheng Xiao wei Weng Dong Gu wei Xiao College of Chemistry and molecular Sciences Hubei Key Laboratory of Electrochemical Power SourcesWuhan UniversityWuhan 430072HubeiChina School of Resource and Environm.ntal Sciences Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and EnergyWuhan UniversityWuhan 430072HubeiChina The Institute of Advanced Studies.Wuhan University Wuhan 430072HubeiChina

Implem.ntation of non-precious electrocatalysts is key-enabling for water electrolysis to relieve challenges in energy and environm.ntal sustainability. Self-supporting ni-V2O3 electrodes consisting of nanostrip-like V2O3 perpendicularly anchored on ni meshes are herein constructed via the electrochemical reduction of soluble naVO3 in molten salts for enhanced electrocatalytic hydrogen evolution. Such a special configuration in morphology and composition creates a well confined interface between ni and V2O3. Experim.ntal and Density-Functional-Theory results confirm that the synergy between ni and V2O3 accelerates the dissociation of H2O for form.ng hydrogen intermediates and enhances the combination of H*for generating H2.

关键词： Hydrogen evolution Electrochemistry molten salt ni V2O3

Controllable conversion of rice husks to Si/C and SiC/C composites in molten salts

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Journal of Energy Chemistry 2021年第4期30卷 102-107页

作者： Da Pang wei Weng Jing Zhou Dong Gu wei Xiao School of Resource and Environm.ntal Sciences Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and EnergyWuhan UniversityWuhan 430072HubeiChina College of Chemistry and molecular Sciences Hubei Key Laboratory of Electrochemical Power SourcesWuhan UniversityWuhan 430072HubeiChina The Institute of Advanced Studies Wuhan UniversityWuhan 430072HubeiChina

Direct conversion of biomass to functional materials is an ideal solution to relieve challenges in environm.ntal and energy *** herein dem.nstrate a molten salt thermoelectrolysis of rice husks(RHs)mainly consisting of organic mass and biosilica to achieve high-efficiency and upgraded utilization of both Si and C in *** coupling pyrolysis of organic mass with electrochemical reduction of silica in molten salts,the thermoelectrolysis of RHs in molten CaCl_(2)-naCl at 800℃ refines the RHs and acidleached RHs to SiC nanowire/C(SiC-nW/C)and Si nanoparticle/C(Si-nP/C),*** present study highlights the molten salt thermoelectrolysis for reclamation of biomass wastes in an affordable and controllable m.nner.

关键词： Rice husks molten salt Silicon Silicon carbide Electrochemistry

High Hole mobility of GaSb Relaxed Epilayer Grown on GaAs Substrate by mOCVD through Interfacial misfit Dislocations Array

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Journal of materials Science & Technology 2012年第2期28卷 132-136页

作者： wei Zhou Xiang Li Sujing Xia Jie Yang Wu Tang K.m.Lau State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Tech- nology of China Chengdu 610054 China Departm.nt of Electronic and Computer Engineering Hong Kong University of Science ＆ Technology Hong Kong China

The structural property of GaSb epilayers grown on semi-insulator GaAs （001） substrate by metalorganic chemical vapor deposition （mOCVD） using Triethylgallium （TEGa） and trimethylantim.ny （TmSb）, was investigated by variation of the Sb：Ga （V/Ill） ratio. An optimum V/Ill ratio of 1.4 was determ.ned in our growth conditions. Using transmission electron microscopy （TEm）, we found that there was an interracial misfit dislocations （ImF） growth mode in our experim.nt, in which the large misfit strain between epilayer and substrate is relaxed by periodic 90 deg. ImF array at the hetero-epitaxial interface. The rms roughness of a 300 nm-thick GaSb layer is only 2.7 nm in a 10μm×10μm scan from atomic force microscopy （AFm） result. The best hole density and mobility of 300 nm GaSb epilayer are 5.27xi06 cm-3（1.20×106） and 553 cm2-V-l.s-1 （2340） at RT （77 K） from Hall measurem.nt, respectively. These results indicate that the ImF growth mode can be used in mOCVD epitaxial technology similar to molecular beam epitaxy （mBE） technology to produce the thinner GaSb layer with low density of dislocations and other defects on GaAs substrate for the application of devices.

关键词： Interfacial misfit dislocations metalorganic chemical vapour deposition misfit dislocation Hole mobility

Phase Transformation and Thermal Stability of Aged Ti-ni-Hf High Temperature Shape memory Alloys

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Journal of materials Science & Technology 2006年第5期22卷 691-695页

作者： Xianglong m.nG wei CAI K.T.Lau L.m.Zhou Liancheng ZHAO School of materials science ＆ Engineering Harbin Institute of Technology Harbin 150001 China Departm.nt of mechanical Engineering The Hong Kong Polytechnic umversity Hung Horn KowloonHong Kong China

The use of ni-rich TiniHf alloys as high temperature shape memory alloys （SmAs） through aging has been presented. For ni-rich Ti80-xnixHf20 alloys, their phase transformation temperatures are averagely increased more than 100 K by aging at 823 K for 2 h. Especially for the alloys with ni-content of 50.4 at. pct and 50.6 at. pct, their martensitic transformation start temperatures （ms） are more than 473 K after aging. TEm observation confirmed that some fine particles precipitate from the matrix during aging. The aged ni-rich TiniHf SmAs show the better thermal stability of phase transformation temperatures than the solutiontreated TiniHf alloys. The fine particles precipitated during aging should be responsible for the increase of phase transformation temperatures and its high stability.

关键词： TiniHf alloy High temperature shape memory alloy Aging Phase transformation

Estimating color appearance of pearlescent bottles using digital camera

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Chinese Optics Letters 2009年第8期7卷 744-747页

作者：傅凌进徐海松 m. Ronnier Luo Guihua Cui wei Ji State Key Laboratory of modern Optical Instrum.ntation Zhejiang University Hangzhou 310027 China Departm.nt of Colour Science University of Leeds Leeds LS2 9JT UK

Pearlescent coatings become highly popular to the modern generation of color rendering materials due to their unique color effect. However, it is quite challenging to evaluate its color appearance by traditional color measurem.nt. A low-cost camera is a highly efficient device for multi-geometry color appearance estimation for pearlescent bottles, which has been achieved through the camera characterization, sample image capturing, and then mathematical transform.ng from RGB （red, green, and blue） values to color appearance attributes based on the color appearance model of CIECAm02. A tele-spectroradiometer for physical measurem.nt together with visual assessm.nt is applied for comparison with the camera method to evaluate the accuracy of camera predictions and discuss the applicability of CIECAm02. The experim.ntal results indicate that the camera data have strong correlation with the physical measurem.nt and also fit well with visual data except for a slight slope shift existing in lightness due to a divinable psychophysical magnitude variation for spatial-dependent color samples. Hence it is feasible to estimate the color appearance of pearlescent bottles using a digital camera.

关键词： Bottles Cameras Digital cameras Video cameras