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Quasi-sure Product Variation of Two-parameter Smooth Martingales on the Wiener Space

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1103-1114页

作者： ji cheng LIU School of Mathematics and Computational Science Zhongshan University Guangzhou 510275 P. R. China Department of Mathematics Huazhong University of Science and Technology Wuhan 430074 P. R. China

In this paper, we prove that the process of product variation of a two-parameter smooth martingale admits an ∞ modification, which can be constructed as the quasi-sure limit of sum of the corresponding product variat... 详细信息

关键词： quasi-sure ∞-modification smooth martingale product variation Kolmogorov's criterion

High-throughput experimental tools for the materials genome initiative

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Chinese Science Bulletin 2014年第15期59卷 1652-1661页

作者： ji-cheng Zhao Department of Materials Science and Engineering The Ohio State University State Key Laboratory of Powder Metallurgy Central South University

The materials innovation infrastructure in the materials genome initiative(MGI)consists of three major components:computational tools,experimental tools,and digital *** article will review experimental tools for high-throughput,high spatial resolution measurements of several materials properties such as elastic modulus,thermal conductivity,specific heat capacity,and thermal *** of these tools on compositionvarying samples such as diffusion multiples can be used to quickly and efficiently obtain composition–phase–structure–property relationships for materials property database *** can also be used in conjunction with theoretical modeling to find and explain unusual effects to improve the predictability of *** micron scale resolution experimental tools are in *** high-throughput tools will be an essential part of MGI.

关键词：计算工具材料性能基因组计划高通量实验高空间分辨率属性数据库组成部分

Facile measurement of single-crystal elastic constants from polycrystalline samples

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npj Computational Materials 2017年第1期3卷 325-332页

作者： Xinpeng Du ji-cheng Zhao Department of Materials Science and Engineering The Ohio State UniversityColumbusOHUSA

Elastic constants are among the most fundamental properties of *** of microstructural evolution and constitutive/micro-mechanistic modeling of materials properties require elastic constants that are predominately measured from single crystals that are labor intensive to grow.A facile technique is developed to measure elastic constants from polycrystalline *** technique is based upon measurements of the surface acoustic wave velocities with the help of a polydimethylsiloxane film grating that is placed on a polished surface of a polycrystalline sample to confine surface acoustic waves that are induced by a femtosecond laser and measured using pump-probe time-domain *** backscatter diffraction is employed to measure the crystallographic orientation along which the surface acoustic wave propagates in each grain(perpendicular to the polydimethylsiloxane grating).Such measurements are performed on several grains.A robust mathematical solution was developed to compute the surface acoustic wave velocity along any crystallographic orientation of any crystal structure with given elastic constants and *** inputting various starting values of elastic constants to compute the surface acoustic wave velocities to match experimental measurements in several distinct crystallographic orientations using an optimization algorithm,accurate elastic constant values have been obtained from seven polycrystalline metal samples to be within 6.8% of single-crystal *** new technique can help change the current scenario that experimentally measured elastic constants are available for only about 1% of the estimated 160,000 distinct solid compounds,not to mention the significant need for elastic constants of various solid solution compositions that are the base of structural materials.

关键词： materials. density. constants

The Optimal Preconditioner of Strictly Diagonally Dominant Z-matrix

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Acta Mathematicae Applicatae Sinica 2008年第2期24卷 305-312页

作者： ji-cheng Li Wei Li Department of Mathematics Xi'an Jiaotong University Xi'an 710049 China

In this paper, we present a series of new preconditioners with parameters of strictly diagonally dominant Z-matrix, which contain properly two kinds of known preconditioners as special cases. Moreover, we prove the monotonicity of spectral radiuses of iterative matrices with respect to the parameters and some comparison theorems. The results obtained show that the bigger the parameter k is（i.e., we select the more upper right diagonal elements to be the preconditioner）, the less the spectral radius of iterative matrix is. A numerical example generated randomly is provided to illustrate the theoretical results.

关键词： Preconditioned method iteration splitting linear system

Conflict Analysis and Detection Based on Model Checking for Spatial Access Control Policy

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Tsinghua Science and Technology 2017年第5期22卷 478-488页

作者： Aijuan Zhang cheng ji Yu Bao Xin Li the School of Computer Science and Technology China University of Mining and TechnologyXuzhou 221116China the Schoo1 of Environment Science and Spatial Inform atics China University of M ining and TechnologyXuzhou 221116China

In this paper, we propose a Multi-granularity Spatial Access Control （MSAC） model, in which multi- granularity spatial objects introduce more types of policy rule conflicts than single-granularity objects do. To analyze and detect these conflicts, we first analyze the conflict types with respect to the relationship among the policy rules, and then formalize the conflicts by template matrices. We designed a model-checking algorithm to detect potential conflicts by establishing formalized matrices of the policy set. Lastly, we conducted experiments to verify the performance of the algorithm using various spatial data sets and rule sets. The results show that the algorithm can detect all the formalized conflicts. Moreover, the algorithm＇s efficiency is more influenced by the spatial object granularity than the size of the rule set.

关键词： spatial object multi-granularity conflict detection model-checking

Early identification of process deviation based on convolutional neural network

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Chinese Journal of Chemical Engineering 2023年第4期56卷 104-118页

作者： Fangyuan Ma cheng ji jingde Wang Wei Sun College of Chemical Engineering Beijing University of Chemical TechnologyBeijing 100029China Center of Process Monitoring and Data Analysis Wuxi Research Institute of Applied TechnologiesTsinghua UniversityWuxi 214072China

A novel process monitoring method based on convolutional neural network(CNN)is proposed and applied to detect faults in industrial *** utilizing the CNN algorithm,cross-correlation and autocorrelation among variables are captured to establish a prediction model for each process variable to approximate the first-principle of physical/chemical relationships among different variables under normal operating *** the process is operated under pre-set operating conditions,prediction residuals can be assumed as noise if a proper model is *** process faults occur,the residuals will increase due to the changes of correlation among variables.A principal component analysis(PCA)model based on the residuals is established to realize process *** monitoring the changes in main feature of prediction residuals,the faults can be promptly *** studies on a numerical nonlinear example and data from two industrial processes are presented to validate the performance of process monitoring based on CNN.

关键词： Process monitoring Residual Principal component analysis Process systems Systems engineering

Solidification in Soft-Contact Continuous Casting Mold with Alternating Electromagnetic Field

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Journal of Iron and Steel Research International 2003年第1期10卷 15-19页

作者： DENG An-yuan HE ji-cheng Northeastern University

The mechanical behavior of the mushy zone was studied in detail. Based on the analysis of conventional high temperature mechanical model, considering the physical phenomenon in casting process, a mechanical model suitable for describing the mechanical behavior of the casting material in twin roll casting process was built. Comparing experimental results to the numerical simulated ones, the mechanical model was proved to be correct.

关键词： strip casting mushy zone mechanical model constitutive equation

Withdrawal of Chinese Physics Letters 28 (2011) 043401 “Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps” by WANG ji-cheng et al.

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Chinese Physics Letters 2011年第10期28卷 302-302页

作者： WANG ji-cheng ZHOU Ke-Ya WANG Yue-Yuan LIAO Qing-Hong LIU Shu-Tian Department of Physics Harbin Institute of TechnologyHarbin 150001

We announce the withdrawal of the article entitled“Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps”,which was published in Chinese Physics Letters[28(4)(2011)043401].The first author,jicheng Wang,had participated in related research with Professor Kirk Madison’s group at the Department of Physics&Astronomy at the University of British Columbia,Canada from September 2008 to February *** though consent had been granted for some of the experimental data to be used by jicheng Wang in his own thesis,its publication had not been *** apologize to Professor *** for the misunderstanding,and to Chinese Physics Letters and the readers of Chinese Physics Letters for any inconvenience this mistake may have caused.

关键词： own Canada Madison

Effect of Ostwald ripening of carbide particles on mechanical properties of SCM435 steel during subcritical annealing

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Journal of Iron and Steel Research International 2018年第7期25卷 724-731页

作者： cheng ji Jun-lu Yao Miao-yong Zhu School of Metallurgy Northeastern University Shenyang 110819 Liaoning China

The Ostwald ripening of carbide particles occurs during the process of subcritical annealing in SCM435 steel, and the degree of ripening influences the microstructure and mechanical properties of the steel. The effects of Ostwald ripening were studied by simulating different soaking time at 680 ~C using SCM435 steel. The spheroidized specimens were analysed by conducting microstructure and mechanical tests. After increasing the soaking time from 2 to 6 h at 680 ~C during subcritical annealing, the number of carbide particles and the spheroidization ratio increased gradually, and the formability was improved. When the soaking time ranged from 6 to 8 h, the spheroidization ratio was similar; however, the number of carbide particles decreased, and the formability gradually worsened. Therefore, by comprehensively comparing the microstructures and mechanical properties, the optimum soaking time was determined to be 6 h at 680 ~C during subcritical annealing to obtain preferable cold heading. In addition, the carbide particles gradually coarsened when the soaking time was extended from 2 to 8 h. A formula was presented to quantitatively characterize the progress of Ostwald ripening of the carbide particles during the subcritical annealing of SCM435 steel, and the relative error was less than 8.02%.

关键词： SCM435 steel Subcritical annealing Ostwald ripening Microstructure - Carbide particle