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The Maximum Principle for One Kind of Stochastic Optimization Problem and Application in Dynamic Measure of Risk

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Acta Mathematica Sinica,English Series 2007年第12期23卷 2189-2204页

作者： Shao Lin ji zhen WU School of Mathematics and Systems Science Shandong University Jinan 250100 P. R. China

The authors get a maximum principle for one kind of stochastic optimization problem motivated by dynamic measure of risk. The dynamic measure of risk to an investor in a financial market can be studied in our framewor... 详细信息

关键词： backward stochastic differential equation perturbation method Ekeland's variational principle dynamic measure of risk

A Memetic Algorithm Based Feature Weighting for Metabolomics Data Classification

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Chinese Journal of Electronics 2014年第4期23卷 706-711页

作者： ZHOU jiarui ZHU Zexuan ji zhen College of Biomedical Engineering and Instrument Science Zhejiang University Shenzhen City Key Laboratory of Embedded System Design College of Computer Science and Software EngineeringShenzhen University

A metaheuristic chain based memetic algorithm namely MCMA is proposed for the classification of metabolomics data. MCMA regards both global evolution and local search as equivalent elemental metaheuristics,and searches with a chain of metaheuristics performed alternatively on the target problem. A hidden Markov model based scheduling mechanism is employed in MCMA for the selection of metaheuristics. By using MCMA for optimizing the linkage weight vector, a feature weighting algorithm for metabolomics data is formed to identify relevant metabolite features and reveal their exact relationships with the given physiological states. An extreme learning machine based classifier is utilized in predicting the physiological states according to the weighted metabolite features. Experimental results on real metabolomics data of clinical liver transplantation demonstrate that the proposed feature weighting and classification method obtains better performance than the other compared algorithms.

关键词： Metabolomics Feature weighting Memetic algorithm

Decomposition Theorems and Conjugate Pair in D_K Spaces

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Acta Mathematica Sinica,English Series 2014年第9期30卷 1513-1525页

作者： ji zhen ZHOU Yu Tian WU School of Sciences Anhui University of Science and Technology School of Mathematics and Information Sciences Zhaoqing University

Let K be a right-continuous and nondecreasing function. A function f analytic in the unit disk D belongs to the space OK if ∫D｜f＇（z）｜2K（1 - ｜z｜2）dA（z）〈 ∞. Decomposition theorems for OK spaces are established in this paper. As an application, we obtain a characterization of interpolation by functions in DK spaces. Furthermore, we characterize functions in DK spaces by conjugate pairs.

关键词： DK spaces decomposition theorem conjugate pair

Modeling black carbon and its potential radiative effects over the Tibetan Plateau

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Advances in Climate Change Research 2016年第3期7卷 139-144页

作者： ji zhen-Ming Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences

A regional climate model(RegCM4.3.4) coupled with an aerosol-snow/ice feedback module was used to simulate the deposition of anthropogenic light-absorbing impurities in snow/ice and the potential radiative feedback of black carbon(BC) on temperature and snow cover over the Tibetan Plateau(TP) in 1990-2009. Two experiments driven by ERA-interim reanalysis were performed, i.e., with and without aerosol-snow/ice feedback. Results indicated that the total deposition BC and organic matter(OM) in snow/ice in the monsoon season(MayeS eptember) were much more than non-monsoon season(the remainder of the year). The great BC and OM deposition were simulated along the margin of the TP in the non-monsoon season, and the higher deposition values also occurred in the western TP than the other regions during the monsoon period. BC-in-snow/ice decreased surface albedo and caused positive surface radiative forcing(SRF)(3.0-4.5 W m^(-2)) over the western TP in the monsoon season. The maximum SRF(5-6 W m^(-2)) simulated in the Himalayas and southeastern TP in the non-monsoon season. The surface temperature increased by 0.1-1.5℃ and snow water equivalent decreased by 5-25 mm over the TP, which showed similar spatial distributions with the variations of SRF in each season. This study provided a useful tool to investigate the mechanisms involved in the effect of aerosols on climate change and the water cycle in the cryospheric environment of the TP.

关键词： Black carbon Tibetan Plateau Aerosolesnow/ice radiative effects Regional climate model

Entrance-channel dynamics in the reaction 40Ca+208Pb

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Science China(Physics,Mechanics & Astronomy) 2019年第12期62卷 34-40页

作者： Xiao Yu Li zhen ji Wu Lu Guo School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing J00049China Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100190China

The entrance-channel dynamics including capture, fusion, and quasifission processes for the reaction ^40Ca+^208Pb is investigated in the fully microscopic time-dependent Hartree-Fock(TDHF) theory. The calculations are performed in three-dimensional Cartesian coordinate without any symmetry restrictions, in which the full Skyrme energy functional SLy4d and SLy5 are *** study the energy dependence of capture cross sections, and find that the experimental data are well reproduced by the TDHF calculations. Both fusion and quasifission events are observed in the reaction ^40Ca+^208Pb. The contact time, mass and charge of quasifission fragments show a wide distribution in SLy4d compared with SLy5, implying that more nucleons are transferred in the SLy4d calculations. We find that the total kinetic energy of quasifission fragments in the TDHF calculations is distributed around Viola systematics, indicating that most of the relative kinetic energy is dissipated in quasifission dynamics.

关键词： capture fusion quasifission TDHF

Structure–activity relationship and mechanisms of reagents used in scheelite flotation

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Rare Metals 2015年第12期34卷 882-887页

作者： Wan-Zhong Yin ji-zhen Wang Zhong-Mei Sun School of Resource and Civil Engineering Northeastern University Design & Research Institute of Zijin

Effects of carboxylic acid collector, benzohydroxamic acid (BHA), sodium hexametaphosphate (SHAP), sodium silicate, and oxalic acid on scheelite flotation were studied through flotation tests, quantum chemical calculation, and flotation solution computational chemistry. In terms of the calculation results, the relationship between chemical reactions occurring on the scheelite surface and molecular structures of the reagents were analyzed. The results show that BHA and carboxylic acid collectors interact with scheelite in different forms and the recovery of scheelite using sodium oleate as collector declines successively from SHAP, sodium silicate, to oxalic acid. Moreover, it is found that the performance of depressant in scheelite flotation is directly related to the group electronegativity, indicating that the latter is a dominant factor that determines the former. These findings will be helpful to the academic research communities of scheelite flotation.

关键词： Scheelite Flotation Flotation reagents Structure–activity relationship

Reconstruction of cylindrically layered media using an iterative algorithm with a stable solution

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The Journal of China Universities of Posts and Telecommunications 2007年第4期14卷 118-121页

作者： CHENG ji-zhen NIU Zuo-yuan CHENG Chong-hu College of Communications and Information Engineering Nanjing Universityof Posts and Telecommunications Nanjing 210003 China

Abstract The reconstruction of cylindrically layered media is investigated in this article. The inverse problem is modeled using a source-type integral equation with a series of cylindrical waves as incidences, and a conventional Born iterative procedure is modified for solving the integral equation. In the modified iterative procedure, a conventional single-point approximation for the calculation of the field inside media is replaced by a multi-points approximation to improve the numerical stability of its solution. Numerical simulations for different permittivity distributions are demonstrated in terms of artificial scattering data with the procedure. The result shows that the procedure enjoys both accuracy and stability in the numerical computation.

关键词： layered media inverse problems integral equations,iterative methods

Metadata and API Based Environment Aware Content Delivery Architecture

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The Journal of China Universities of Posts and Telecommunications 2006年第1期13卷 40-43,48页

作者： SONG jiang-wang MI zheng-kun CHENG ji-zhen College of Communication and Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 P.R. China

One of the limitations of current content delivery networks is lack of support for environment aware content delivery. This paper first discusses the requirements of such support, and proposes a new metadata gateway based environment aware content delivery architecture. The paper discusses in some details key functions and technologies of environment aware content delivery architecture, including its APIs and control policies. Finally the paper presents an application to illustrate advantages of environment aware content delivery architecture in the context of next generation network.

关键词： adaptive service provisioning environment aware adaptation content delivery metadata

Influence of lanthanum on enhancement of mechanical and electrical properties of Cu-Al_2O_3 composites

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Journal of Rare Earths 2019年第5期37卷 534-540页

作者： Yifan Zhang zhen ji Chengchang jia Guimin Liu Farong Wan Qian Zhan School of Materials Science and Engineering University of Science and Technology Beijing Faculty of Remanufacturing Engineering Academy of Armored Forces Engineering

Two kinds of Cu-Al_2O_3 composites(with and without La) were prepared via mechanical alloying-spark plasma sintering(MA-SPS) method. Microstructure, mechanical properties and electrical resistivity were investigated systematically using metallography, scanning electron microscopy, transmission electron microscopy, mechanical and electrical properties testing. The results indicate that an appropriate amount of La can homogenize the distribution of Al_2O_3. As such, yield strength, ultimate tensile strength and elongation of Cu-Al_2O_3-La are greatly increased. Some semi-coherent interface between Cu and Al_2O_3 is found, which means a low interface energy. The grain shape of Cu changes to irregular band with the addition of La. This change results in a density decrease of grain boundary and reduces electrical resistance. Lanthanum may exist in the form of La_2O_3.

关键词： Cu-Al2O3 composite Lanthanum Mechanical alloying Spark plasma sintering Electrical resistivity Rare earths