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Carboalumination-Epoxide Ring Opening for the Formation of 1,4-Disubstituted （Z）-3,6-Alkadienols

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Chinese Journal of Chemistry 2013年第6期31卷 773-778页

作者： Quan Zhang Yuhuan Jing David C. Myles Yong Li Yue Chen College of Pharmacy State Key Laboratory of Elemento-Organic Chemistry and Tianjin Key Laboratory of Molecular Drug Research Nankai University Tianjin 300071 China Kosan Biosciences Inc. 3832 Bay Center Place Hayward California 94545 USA

Allylalumination of alkynes （i.e. forming Negishi＇s （Z）-alkenyl dialkylalane） followed by alkenylation of epoxides provides 1,4-disubstituted （Z）-3,6-alkadienols. The alkenylation can be facilitated by the presence of a neighbouring coordinating group in the epoxides. This ＂one-pot＂ approach has been successfully applied in the large-scale production of C 10--C 15 fragment of 9,10-didehydroepothilone D （a synthetic epothilone analog as an anti-cancer agent in phase 2 clinical trials）.

关键词： carboalumination-epoxide ring opening 1,4-disubstituted (Z)-3,6-alkadienols

Injection molding and debinding of micro gears fabricated by micro powder injection molding

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International Journal of Minerals,Metallurgy and Materials 2013年第1期20卷 82-87页

作者： Xin-lei Ni Hai-qing Yin Lin Liu Shan-jie Yi Xuan-hui Qu School of Materials Science and Engineering University of Science and Technology Beijing School of Mechanical and Electrical Engineering China University of Mining and Technology (Beijing)

Micro powder injection molding （μPIM） was investigated for possible mass production of micro-components at rela- tively low cost. However, scaling down to such a level produces challenges in injection molding and debinding. Micro gears were fabricated by μPIM from in-house feedstock. The effect of injection speed and injection pressure on the replication of the micro gear cavity was investigated. Solvent debinding and thermal debinding processes were discussed. The results show that micro gears can be successfully fabricated under the injection pressure of 70 MPa and the 60% injection speed. Either too low or too high injection speed can cause incomplete filling of micro gears. The same is the case with too low injection pressure. Too high injection pressure can bring cracks. Solvent debinding of micro gears was performed in a mixture of petroleum ether and ethanol. Subsequently, micro gears were successfully debound by a multistep heating schedule.

关键词： gear manufacture micro gears injection molding debinding zirconia

EQUIVARIANT HEAT INVARIANTS OF THE LAPLACIAN AND NONMININMAL OPERATORS ON DIFFERENTIAL FORMS

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Acta Mathematica Scientia 2011年第3期31卷 805-814页

作者：王勇 School of Mathematics and Statistics Northeast Normal University

In this paper,we compute the first two equivariant heat kernel coeffcients of the Bochner Laplacian on differential *** first two equivariant heat kernel coeffcients of the Bochner Laplacian with torsion are also *** also study the equivariant heat kernel coeffcients of nonminimal operators on differential forms and get the equivariant Gilkey-Branson-Fulling formula.

关键词： equivariant heat kernel asymptotics Bochner Laplacian nonmininmal operators Gilkey-Branson-Fulling formula

Boundary Gap Based Reactive Navigation in Unknown Environments

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IEEE/CAA Journal of Automatica Sinica 2021年第2期8卷 468-477页

作者： Zhao Gao Jiahu Qin Shuai Wang Yaonan Wang the Department of Automation University of Science and Technology of ChinaHefei 230027China the College of Electrical and Information Engineering Hunan UniversityChangsha 410082 the National Engineering Laboratory for Robot Visual Perception and Control Technology Changsha 410082China

Due to the requirements for mobile robots to search or rescue in unknown environments,reactive navigation which plays an essential role in these applications has attracted increasing ***,most existing reactive methods are vulnerable to local minima in the absence of prior knowledge about the *** paper aims to address the local minimum problem by employing the proposed boundary gap(BG)based reactive navigation ***,the narrowest gap extraction algorithm(NGEA)is proposed to eliminate the improper ***,we present a new concept called boundary gap which enables the robot to follow the obstacle boundary and then get rid of local ***,in order to enhance the smoothness of generated trajectories,we take the robot dynamics into consideration by using the modified dynamic window approach(DWA).Simulation and experimental results show the superiority of our method in avoiding local minima and improving the smoothness.

关键词： Boundary gap local minima reactive navigation unknown environments

Radiative heat transfer and thermal characteristics of Fe-based oxides coated SiC and Alumina RPC structures as integrated solar thermochemical reactor

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Science china(Technological Sciences) 2018年第12期61卷 1788-1801页

作者： GUENE LOUGOU Bachirou SHUAI Yong PAN RuMing CHAFFA Gédéon AHOUANNOU Clément ZHANG Hao TAN HePing Key Laboratory of Aerospace Thermophysics of Ministry of Industry and Information Technology Harbin Institute of Technology School of Energy Science and Engineering Harbin Institute of Technology Laboratory of Energetics and Applied Mechanics (LEMA) Polytechnic College of Abomey-Calavi Abomey-Calavi University

This paper investigated radiative heat transfer and thermal characteristics of Fe-based oxides coated SiC and Alumina reticulated porous ceramic structures as integrated solar thermochemical ***-flux solar radiation absorption and axial temperature distribution in the ceramic foams reactor were analyzed by adopting surface-to-surface radiation model coupled to the P1approximation for radiation heat *** radiative heat transfer and thermal characteristics of different foam-type RPC structures,including SiC,CeO_2,FeAl_2O_4,NiFeAlO_4,Fe_3O_4/SiC,and NiFe_2O_4/SiC were *** mass flow rate and foam structural parameters,including the permeability,pore mean cell size,and extinction coefficients have significantly affected the axial temperature distribution,pressure drop,heat transfer,and fluid *** porous structure to the solar receiver could maximize the incorporation of redox powder in the reacting medium,lower the pressure drop,and enhance the thermal performance of the thermochemical reacting *** structure was the candidate materials in the case where more heat flux and high axial temperature distribution is ***,Fe-based oxide coated Al_2O_3structure could be considered regarding the heat transfer enhancement along with the catalyst activity of oxygen carriers for solar thermochemical reacting system performance.

关键词： solar thermochemical reactor reticulated porous ceramics heat transfer and fluid flow pore mean cell size permeability and pressure drop

Two-stage Scheduling for Island CPHH IES Considering Plateau Climate

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1775-1786页

作者： Yuchen Pu Qi Li Yibin Qiu Xueli Zou Weirong Chen School of Electrical Engineering Southwest Jiaotong UniversityChengdu 611756China

In this paper,an island integrated energy system(IES)combining power,heat and hydrogen(CPHH)is built,and optimal power-heat-hydrogen scheduling is studied under actual plateau meteorological *** the comprehensive demands of residents,an IES including renewable energy sources(RESs),fuel cell,electrolyzer,electric boiler,thermal energy storage device and new energy vehicles is established and *** the first stage of operation,according to the prediction of RESs and demands,day-ahead optimization is carried out which aims to minimize operation cost,while electric vehicles(EVs)are considered as special demand response(DR)*** the second stage of operation,ultra-short-term prediction is implemented to provide prediction data for model predictive control(MPC),realizing real-time *** as a CPHH system,the fuel cell and electrolyzer collaborate to meet various needs of the plateau residential area with high *** addition,the method and IES structure proposed in this paper is compared with other options.

关键词： CPHH feul cell hydrogen island IES scheduling

Hopf bifurcation analysis of Chen circuit with direct time delay feedback

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Chinese Physics B 2010年第3期19卷 164-175页

作者：任海鹏李文超刘丁 School of Automation and Information Engineering Xi'an University of Technology

Direct time delay feedback can make non-chaotic Chen circuit chaotic. The chaotic Chen circuit with direct time delay feedback possesses rich and complex dynamical behaviours. To reach a deep and clear understanding of the dynamics of such circuits described by delay differential equations, Hopf bifurcation in the circuit is analysed using the Hopf bifurcation theory and the central manifold theorem in this paper. Bifurcation points and bifurcation directions are derived in detail, which prove to be consistent with the previous bifurcation diagram. Numerical simulations and experimental results are given to verify the theoretical analysis. Hopf bifurcation analysis can explain and predict the periodical orbit （oscillation） in Chen circuit with direct time delay feedback. Bifurcation boundaries are derived using the Hopf bifurcation analysis, which will be helpful for determining the parameters in the stabilisation of the originally chaotic circuit.

关键词： direct time delay feedback bifurcation diagram Hopf bifurcation bifurcation boundary

A note on modular forms and generalized anomaly cancellation formulas

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Science china Mathematics 2013年第1期56卷 55-65页

作者： LIU KeFeng WANG Yong Center of Mathematical Sciences Zhejiang University Department of Mathematics University of California at Los Angeles School of Mathematics and Statistics Northeast Normal University

By studying modular invariance properties of some characteristic forms,we prove some new anomaly cancellation formulas which generalize the Han-Zhang and Han-Liu-Zhang anomaly cancellation formulas.

关键词： modular invariance anomaly cancellation formulas

Computation of deformation-induced textures in electrodeposited nickel coating

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中国有色金属学会会刊：英文版 2006年第B01期16卷 232-238页

作者：龙士国周益春潘勇 Key Laboratory for Advanced Materials and Rheological Properties of Ministry of education Faculty of Material Photoelectron PhysicsXiangtan UniversityXiangtan 411105China

The deformation-induced textures in electrodeposited nickel coating were numerically studied. The finite element method (FEM) for polycrystalline was developed based on Taylor model. Then the deformation-induced textures in electrodeposited nickel coating with initial random and lamellar texture were simulated under tensile load. It is found that the initial textures significantly influence the deformation-induced textures. For nickel coating with the initial random textures, when the tensile strain is about 40%, there are some lamellar textures. For nickel coating with the initial lamellar textures, the lamellar texture is more intensity with the increase of the tensile strain. With the increase of the tensile strain in the coating, there are more pronounced element distortion and a more inhomogeneous deformation. Due to the different crystal orientations, the grain-scale roughness is observed. With increasing tensile strain in the coating, the surface grain-scale roughness increases on the free surface. The surface roughness of the coating with initial random texture is lower than that with the initial lamellar texture.

关键词：电沉积镍镀层多晶态形变诱发织构