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On Riemann-Finsler geometry

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Chinese Science Bulletin 1998年第6期43卷 447-450页

作者： mo xiaohuan school of mathematical sciences, peking university, Beijing 100871,{2. school of mathematical{2. Peking University Beijing China

The history of Finsler geometry is reviewed and briefly recent development in Finsler geometry and its application is completed systematically. Furthermore, an interesting open problem has been proposed in this field.

关键词： Finsler space Chern connection Hilbert form Minkowski potential projective sphere bundle.

Some constructions of projectively flat Finsler metrics

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Science china Mathematics 2006年第5期49卷 703-714页

作者： mo xiaohuan, SHEN Zhongmin & YANG Chunhong LMAM, {2. of {2. sciences, peking university, Beijing 100871, china Department of {2. sciences, Indiana university-Purdue university, Indianapolis, IN 462.2.32.6, USA Department of Mathematics, Inner mongolia university, Hohhot 01002., china LMAM School of Mathematical Sciences Peking University Beijing 100871 China Department of mathematical sciences Indiana University-Purdue University Indianapolis IN 46202-3216 USA Department of Mathematics Inner Mongolia University Hohhot 010021 China

In this paper, we find some solutions to a system of partial differential equations that characterize the projectively flat Finsler metrics. Further, we discover that some of these metrics actually have the zero flag ... 详细信息

关键词： Randers metric, (α,β)-metric, Finsler metric, projectively flat metric, Scurvature.

Recent developments and some open problems in Finsler geometry

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Chinese Science Bulletin 2001年第13期46卷 1059-1061页

作者： mo xiaohuan & SHEN Zhongmin1. {2. of {2. sciences, peking university, Beijing 100871, china 2. Department of Mathematics, IUPUI 402.N. Blackford Street, Indianapolis, IN 462.2.32.6, USA school of mathematical{2. Peking University Beijing China Department of Mathematics IUPUI Indianapolis USA

Finsler geometry is just Riemannian geometry without the quadratic restriction. Recent studies on Finsler geometry have taken on a new look. In this article, we will briefly discuss recent developments and some open p... 详细信息

关键词： Finsler geometry open problems recent development.

Insights into the mechanism of multiple Cu-doped Co Fe_(2.O_(4)nanocatalyst activated peroxymonosulfate for efficient degradation of Rhodamine B

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Journal of Environmental sciences 2024年第3期137卷 382-394页

作者： Yuanmin mo Xiaoping Zhang school of Environment&Energy South China University of TechnologyGuangzhou Higher Education Mega CentreGuangzhou 510006China The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters of Ministry of Education Guangzhou 510006China Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and Recycling Guangzhou 510006China Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal Guangzhou 510006China

The multiple metal catalyst as a promising nanomaterial has shown excellent activity in the peroxymonosulfate(PMS)activation for pollutant ***,the role of special sites and in-depth understanding of the PMS activation mechanism are not fully *** this study,a Cu-doped CoFe_(2.O_(4)nanocatalyst(0.5CCF)was synthesized by a sol-gel and calcination method,and used for PMS activation to remove Rhodamine B(RhB).The results showed that the Cu doping obviously enhanced the catalytic performance of CoFe_(2.O_(4),with 99.70%of RhB removed by 0.5CCF while 74.91%in the CoFe_(2.O_(4)within 15 *** on the X-ray photoelectron spectroscopy and electrochemical analysis,this could be ascribed to the more low valence of Co and Fe species generated on the 0.5CCF and faster electron transfers occurred in the 0.5CCF due to the Cu *** addition,Cu doping could provide more reaction sites for the 0.5CCF to activate PMS for RhB *** metal species and the surface hydroxyl were the reaction sites of PMS activation,and the surface hydroxyl played an important role in surface-bound reactive species *** the PMS activation,the Cu not only activated PMS to produce reactive oxygen species(ROS),but also regenerated Co^(2.)and Fe^(2.)to accelerate the PMS *** non-radical of ^(1)O_(2.was the main ROS with a 99.35%of contribution rate,and the SO_(5)^(·–)self-reaction was its major *** study provides a new insight to enhance the PMS activation performance of multiple metal catalysts by Cu doping in wastewater treatment.

关键词： Cu-doped CoFe_(2.O_(4)nanocatalyst PMS activation Mechanism Rhodamine B removal

Efficient estimation for additive hazards regression with bivariate current status data

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Science china Mathematics 2012年第4期55卷 763-774页

作者： TONG XingWei 1,,HU Tao 2.& SUN JianGuo 3,4 1 school of mathematical{2.,Beijing Normal university,Beijing 100875,china 2.school of mathematical{2.,Capital Normal university,Beijing 100048,china 3 school of Mathematics,Jilin university,Changchun 130012.china 4 Department of Statistics,university of Missouri,Columbia,mo 652.1,USA 1. school of mathematical{2. Beijing Normal University Beijing 100875 China2. School of Mathematical Sciences Capital Normal University Beijing 100048 China3. School of Mathematics Jilin University Changchun 130012 China4. Department of Statistics University of Missouri Columbia MO 65211 USA

This paper discusses efficient estimation for the additive hazards regression model when only bivariate current status data are available. Current status data occur in many fields including demographical studies and tumorigenicity experiments （Keiding, 1991; Sun, 2.06） and several approaches have been proposed for the additive hazards model with univariate current status data （Linet M., 1998; Martinussen and Scheike, 2.02.. For bivariate data, in addition to facing the same problems as those with univariate data, one needs to deal with the association or correlation between two related failure time variables of interest. For this, we employ the copula model and an efficient estimation procedure is developed for inference. Simulation studies are performed to evaluate the proposed estimates and suggest that the approach works well in practical situations. An illustrative example is provided.

关键词： bivariate current status data copula model counting processes efficient estimation joint survivalfunction

Comprehensive modeling strategy for thermomechanical tribological behavior analysis of railway vehicle disc brake system

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Friction 2024年第1期12卷 74-94页

作者： Jiabao YIN Chun LU Jiliang mo school of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province Chengdu 610031China

A comprehensive modeling strategy for studying the thermomechanical tribological behaviors is proposed in this *** wear degradation considering the influence of temperature(T)is predicted by Archard wear model with the help of the UMESHmoTION subroutine and arbitrary Lagrangian–Eulerian(ALE)remeshing *** the proposed method,the thermomechanical tribological behaviors of railway vehicle disc brake system composed of forged steel brake disc and Cu-based powder metallurgy(PM)friction block are studied *** effectiveness of the proposed methodology is validated by experimental test on a self-designed scaled brake test bench from the perspectives of interface temperature,wear degradation,friction noise and vibration,and contact status *** work can provide an effective way for the investigation of thermomechanical tribological behaviors in the engineering field.

关键词： tribological behaviors thermomechanical field wear prediction finite element simulation disc brake system railway vehicle

The recirculation flow after different cross-section shaped high-rise buildings with applications to ventilation assessment and drag parameterization

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Building Simulation 2024年第4期17卷 509-524页

作者： Keyi Chen Ziwei mo Jian Hang school of Atmospheric {2. Sun Yat-sen University&Southern Marine Science and Engineering Guangdong LaboratoryZhuhai519082China Key Laboratory of Tropical Atmosphere-Ocean System Ministry of EducationZhuhai519000China

The building cross-section shape significantly affects the flow characteristics around buildings,especially the recirculation region behind the high-rise *** generic building shapes including square,triangle,octagon,T-shaped,cross-shaped,#-shaped,H-shaped and L-shaped are examined to elucidate their effects on the flow patterns,recirculation length L and areas A using computational fluid dynamics(CFD)simulations with Reynolds-averaged Navier-Stokes(RANS)*** sizes and positions of the vortexes behind the buildings are found to be substantially affected by the building shapes and subsequently changing the recirculation *** recirculation length L is in the range of 1.6b-2.6b with an average of *** maximum L is found for L-shaped building(2.6b)while the shortest behind octagon building(1.6b).The vertical recirculation area Av is in the range of 1.5b^(2.-3.2.^(2.and horizontal area Ah in 0.9b^(2.-2.2.^(2..The L,Av and Ah generally increase with increasing approaching frontal area when the wind direction changes but subject to the dent structures of the#-shaped and cross-shaped *** area-averaged wind velocity ratio(AVR),which is proposed to assess the ventilation performance,is in the range of 0.05 and 0.14,which is around a three-fold difference among the different building *** drag coefficient parameterized by Ah varies significantly,suggesting that previous models without accounting for building shape effect could result in large uncertainty in the drag *** findings provide important reference for improving pedestrian wind environment and shed some light on refining the urban canopy parameterization by considering the building shape effect.

关键词： recirculation region cross-section shape ventilation assessment drag parameterization computational fluid dynamics

High thermoelectric properties of Cu_(2.TeeAg_(2.Te composite with Fe addition and non-stoichiometric Te

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Journal of Materiomics 2024年第1期10卷 37-44页

作者： Wenxiu Li Su Dun Bin Xiao Jun Wang Xinba Yaer Chun Ying Ye Li xiaohuan Wang Huijun Kang school of Materials Science and Engineering Inner Mongolia University of TechnologyHohhot010051China Research and Development Center HUA Cloud Intelligent Healthcare Co.LtdShenzhen518000China College of sciences Inner Mongolia University of TechnologyHohhot010051China Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian116024China

Cu_(2.Te-based materials are a type of superionic conductor belonging to the class of phonon-liquid elec-tron-crystal materials and have achieved high ZT values by doping and ***,it is easy to form copper vacancies in Cu_(2.Te which leads to an excessive carrier concentration and then results in a low Seebeck ***,controlling copper ion migration and optimizing carrier concen-tration is essential to improve the thermoelectric performance of Cu_(2.*** paper reports high-performance Cu_(2.TeeAg_(2.Te composite with high application value in the low-middle temperature re-gion,which is achieved by fine tuning the carrier concentration using Fe addition and non-stoichiometric Te,as well as controlling the thermal conductivity of composite.A high ZT of~1.2.is obtained in AgCu_(0.97)Fe_(0.03)Te_(0.96)at a low temperature of 573 ***,the phase transition mechanism of Cu_(2.TeeAg_(2.Te and its effect on the thermoelectric transport performance are revealed that go beyond nanostructuring and single-doping,which provides a strong theoretical basis for research and perfor-mance improvement of thermoelectric materials in this system.

关键词： Thermoelectric AgCuTe Fe addition Non-stoichiometric Te

On the weak convergence of super-Brownian motion with immigration

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Science china Mathematics 2009年第9期52卷 1875-1886页

作者： ZHANG Mei school of mathematical{2., Beijing Normal university, Beijing 100875, china school of mathematical{2. Beijing Normal University Beijing 100875 China

We prove fluctuation limit theorems for the occupation times of super-Brownian motion with immigration. The weak convergence of the processes is established, which improves the results in references. The limiting proc... 详细信息

关键词： super-Brownian motion with immigration occupation time process central limit theorem tightness 60J80 60F05