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RELATIONS BETWEEN TWO SETS OF FUNCTIONS DEFINEDBY THE TWO INTERRELATED ONE-SIDE LIPSCHITZCONDITIONS

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Journal of Computational Mathematics 1999年第5期17卷 457-462页

作者： Zhao, SS wang, cy Zhang, GF Lanzhou Univ Dept Math Lanzhou 730000 Peoples R China Dept Commun Commun Ctr Lanzhou 730030 Gansu Province Peoples R China

In the theoretical study of numerical solution of stiff ODEs, it usually assumes that the righthand function f(y) satisfy one-side Lipschitz condition less than or equal to v(1)parallel to y - z parallel to(2),f : Omega subset of or equal to C-m --> C-m, or another related one-side Lipschitz condition [F(Y) - F(Z), Y - Z](D) less than or equal to v'parallel to Y - Z parallel to(D)(2), F : Omega(s) subset of or equal to C-ms --> C-ms, this paper demonstrates that the difference of the two sets of all functions satisfying the above two conditions respectively is at most that v' - v' only is constant independent of stiffness of function f.

关键词： stiff ODEs one-side Lipschitz condition logarithmic norm

Laboratory Assessment of Lubricants for Wheel/Rail Lubrication

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Journal of Materials Science & Technology 1997年第1期13卷 57-60页

作者： Zhao, XZ Liu, JJ Zhu, BL wang, cy ZHENGZHOU RES INST MECH ENGN ZHENGZHOU 450052PEOPLES R CHINA

The antiwear properties of two wheel/rail lubricating oils were tested and compared on an Amsler machine. Under same testing conditions, oil A (developed by authors) showed much better wear resistance and higher load-carrying capacity than oil B (imported from abroad). The X-ray diffraction (XRD) analyses of the worn surfaces showed that different extreme pressure (EP) lubricating films were formed on the surfaces when the rollers were lubricated with different oils under boundary lubrication condition. The EP film of oil A was a composite film containing three compounds, FeO, FeSx and FeP, while oil B formed only a simple EP film of FePO4. The composite EP film showed lower shear strength and better antiwear property than the simple EP film, which brought about different wear resistance df the two wheel/rail lubricating oils.

关键词： Lubricating oils

Preparation of Sodium Borosilicate Transparent Bulk Gel

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Journal of Materials Science & Technology 1996年第4期12卷 303-306页

作者： Xiang, WD wang, ZC Yang, QZ Zhao, WX wang, cy Ding, ZS Weng, WJ DALIAN INST LIGHT IND INST GLASS & INORGAN MATDALIAN 116001PEOPLES R CHINA ZHEJIANG UNIV DEPT MAT SCI & ENGNHANGZHOU 310027PEOPLES R CHINA

A transparent bulk sodium borosilicate gel with the composition of 72SiO(2) . 23B(2)O(3) . 5Na(2)O (wt pct) was prepared by using tetraethyl orthosilicate, boric acid, sodium methoxide, sodium alkoxide, sodium acetate as precursor, methanol, ethanol and glycolic methyl ether as precursor solvent and hydrochloric acid as catalyst. Properties of gel, varied principle and related mechanism of conversion for sol to gel are discussed. Ideal composition and dry process are given in this work.

关键词： Gels

Multiple-Reference-Frame PI Controller For Three-phase Power Converters

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Multiple-Reference-Frame PI Controller For Three-phase Power...

A Modified Current-Doubler Rectifier for DC-DC Converters to Achieve Balanced Average Currents

2006中国电工技术学会电力电子学会第十届学术年会

作者： TIMOTHY cy wang GLOBAL RESEARCH CENTER GE ShanghaiChina

＜正＞Comprehensive study of the multiple-reference-frame（MRF） PI controller design will be discussed in this paper. Firstly, the design guideline for the proportional constant and integral constants will be presented. Instead of the conventional integral constant, the time constant is considered fundamental. Secondly, the delay compensation in MRF controller will be analyzed. The approach that can enhance the stability margin is discussed. Finally, anti-windup in the MRF PI controller will be studied. All the results of the analysis have been validated.

关键词： control power converter anti-windup

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A Modified Current-Doubler Rectifier for DC-DC Converters to...

第4届国际电力电子及运动控制国际会议

作者： Osama Abdel-Rahman Timothy cy wang Issa Batarseh University of Central Florida Department of Electrical and Computer Engineering Orlando Florida 32816USA Global Research Center General Electric Shanghai P.R.China University of Central Florida Department of Electrical and Computer Engineering Orlando Florida 32816USA

＜正＞ Half-bridge DC-DC converter with a current doubler rectifier is suited for low-voltage high-current on-board DC-DC converters. Due to the fact that peak current-mode cannot be directly applied to the conventional half-bridge DC-DC converter, the voltage mode control is most likely utilized. However, in this case, the DC current sharing between two inductors of the current-doubler rectifier cannot be achieved due to unbalanced DC resistive parameters. In this paper, a modified half-bridge DC-DC converter is proposed and verified by an established steady-state mathematical model. Simulation and experimental results shows that the current sharing and zero DC transformer magnetizing current arc achieved.

关键词： Half-bridge DC-DC converter current doubler rectifier current sharing

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波纹板在转动流体中的阻力

冶金科技译丛 1990年第1期 102-106页

作者： wang,cy 刘五秀

Swarm intention identification via dynamic distribution probability image

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Chinese Journal of Aeronautics 2024年第10期37卷 380-392页

作者： Yinhan wang Jiang wang Shaoming HE Fei wang Qi wang School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Institute of Computing Technology Chinese Academy of SciencesBeijing 100190China

In the realm of decision-making for defense and security applications,it is paramount to swiftly and accurately identify the intentions of incoming *** identification methods predominantly focus on single-target applications and overlook the perturbations introduced by measurement *** this study,we propose a novel concept:the Dynamic Distribution Probability(DDP)image,which is constructed using the estimated state and its covariance *** grayscale pixel value within the image signifies the probability of the presence of the agent within the *** proposed identification scheme integrates the use of Extended Kalman Filter(EKF),Convolutional Neural Network(CNN),Back Propagation(BP)network,and Gated Recurrent Unit(GRU)***,the DDP image is processed through a CNN to distill the formation characteristics,and the estimated swarm state from EKF is inputted into a BP network to deduce the kinematic *** outputs from both networks are summed and subsequently channeled into a GRU network to capture temporal *** numerical simulations and flight experiments are presented to demonstrate the robust anti-noise capability of the proposed scheme compared with conventional methods,as well as its superior training efficiency.

关键词： Intention Identification Kalman filters Convolutional neural networks Swarm intelligence

The reformation of catalyst:From a trial-and-error synthesis to rational design

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Nano Research 2024年第4期17卷 3261-3301页

作者： Ligang wang Jiabin Wu Shunwu wang Huan Liu Yao wang Dingsheng wang Department of Chemistry Tsinghua UniversityBeijing 100084China

The appropriate catalysts can accelerate the reaction rate and effectively boost the efficient conversion of various molecules,which is of great importance in the study of chemistry,chemical industry,energy,materials and environmental ***,efficient,environmentally friendly,and easy to operate synthesis methods have been used to prepare various types of *** previous studies have reported the synthesis and characterization of the aforementioned catalysts,more still remain in trial and error methods,without in-depth consideration and improvement of traditional synthesis ***,we comprehensively summarize and compare the preparation methods of the trial-and-error synthesis strategy,structure–activity relationships and density functional theory(DFT)guided catalysts rational design for nanomaterials and atomically dispersed *** also discuss in detail the utilization of the nanomaterials and single atom catalysts for converting small molecules(H_(2)O,O_(2),CO_(2),N_(2),etc.)into value-added products driven by electrocatalysis,photocatalysis,and ***,the challenges and outlooks of mass preparation and production of efficient and green catalysts through conventional trial and error synthesis and DFT theory are featured in accordance with its current development.

关键词： trial-and-error synthesis structure–activity relationships density functional theory(DFT)guidance nanomaterials atomically dispersed catalysts

Numerical Analysis of PRISM-PY Calculations for Hard-and Soft-Core Generic Polymer Models

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Chinese Journal of Polymer Science 2024年第4期42卷 532-543页

作者： Qiang wang Department of Chemical and Biological Engineering Colorado State University1370 Campus DeliveryFort CollinsCO80523-1370USA

Generic polymer models capturing the chain connectivity and excluded-volume interactions between polymer segments can be classified, according to whether or not the 3D integral of the latter diverges, into hard- and soft-core models. Taking homogeneous systems of compressible homopolymer melts (or equivalently homopolymer solutions in an implicit, good solvent) in the continuum as an example, we recently compared the correlation effects on the structural and thermodynamic properties of the hard- and soft-core models given by the polymer reference interaction site model (PRISM) theory with the Percus-Yevick (PY) closure (Polymers 2023, 15, 1180). Here we analyzed in detail the numerical errors and behavior of the interchain pair correlation functions (PCFs) given by the PRISM-PY calculations of these models using an efficient numerical approach that we proposed. Our numerical approach has the least number of independent variables to be iteratively solved, analytically treats the discontinuities caused by the non-bonded pair potential (such as that of the hard spheres) and takes only the inverse Fourier transform of the interchain indirect PCF between polymer segments (which is continuous and decays towards 0 with increasing wavenumber much faster than both the interchain direct and total PCFs), and is essential for us to accurately solve the PRISM-PY theory for chain length N as large as 106. To capture the correlation-hole effect, the real-space cut-off in the PRISM calculations should be proportional to the square root of N.

关键词： Generic polymer models Soft potentials Polymer reference interaction site model theory