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A Novel Model for Describing Rail Weld Irregularities and Predicting Wheel-Rail Forces Using a Machine Learning Approach

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Computer Modeling in Engineering & sciences 2025年第1期142卷 555-577页

作者： Linlin Sun Zihui Wang Shukun Cui Ziquan Yan Weiping Hu Qingchun Meng State Key Laboratory of High-Speed Railway Track System China Academy of Railway Sciences Corporation LimitedBeijing100081China Railway Engineering Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China School of Aeronautic Science and Engineering Beihang UniversityBeijing100191China

Rail weld irregularities are one of the primary excitation sources for vehicle-track interaction dynamics in modern high-speed *** can cause significant wheel-rail dynamic interactions,leading to wheel-rail noise,component damage,and *** researchers have employed the vehicle-track interaction dynamic model to study the dynamic interactions between wheel and rail induced by rail weld geometry ***,the cosine wave model used to simulate rail weld irregularities mainly focuses on the maximum value and neglects the geometric *** this study,novel theoretical models were developed for three categories of rail weld irregularities,based on measurements of the high-speed railway from Beijing to *** vertical dynamic forces in the time and frequency domains were compared under different running *** forces generated by the rail weld irregularities that were measured and modeled,respectively,were compared to validate the accuracy of the proposed ***,based on the numerical study,the impact force due to rail weld irrregularity is modeled using an Artificial Neural Network(ANN),and the optimum combination of parameters for this model is *** results showed that the proposed model provided a more accurate wheel/rail dynamic evaluation caused by rail weld irregularities than that established in the *** ANN model used in this paper can effectively predict the impact force due to rail weld irrregularity while reducing the computation time.

关键词： Rail weld irregularity high-speed railway vehicle-track coupled dynamics wheel/rail dynamic vertical force artificial neural networks

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Correlation Analysis of Transient Heat Transfer Characteristics for Air Precooling Aggregate

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Journal of Thermal Science 2017年第2期26卷 144-152页

作者： GUO Chaohong ZENG Miao LU Fei TANG Dawei GUAN Wei LI Li FU Tingwu Institute of Engineering Thermophysics Chinese Academy of Sciences Northwest Engineering corporation Limited Power Construction Corporation of China

In dam works, air precooling of aggregate is a common and effective method to avoid temperature cracks in concrete structure. In order to offer a reliable design theory for the air precooling process to avoid unreasonable energy consumption, the transient heat transfer characteristics of the aggregate are intensively analyzed. The combined structure of the aggregate and the interstitial space in the hopper is treated as a porous structure, and the space-average method is used to simulate the transient heat transfer process. Simulation results show that size of the hopper and the average air velocity in the cross section have great influence on the transient heat transfer process of the aggregate, while the porosity in the range of 0.4-0.5 has little influence. Nomograms are abstracted from simulation results, and then correlations of the compared excess temperature are precisely fitted to predict the air precooling transient heat transfer process of the aggregate.

关键词： Air precooling Aggregate Transient heat transfer Nomogram

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An Experimental and Numerical Thermal Flow Analysis in a Solar Air Collector with Different Delta Wing Height Ratios

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Frontiers in Heat and Mass Transfer 2024年第2期22卷 491-509页

作者： Ghobad Shafiei Sabet Ali Sari Ahmad Fakhari Nasrin Afsarimanesh Dominic Organ Seyed Mehran Hoseini Department of Mechanical Engineering Shahrood Branch lslamic Azad UniversityShahroodIran airflow sciences corporation LivoniaMIUSA School of Civil and Mechanical Engineering Curtin UniversityBentleyAustralia Department of English as an Additional Language(EAL) Heriot-Watt UniversityGalashielsScotland

This study conducts both numerical and empirical assessments of thermal transfer and fluid flow characteristics in a Solar Air Collector(SAC)using a Delta Wing Vortex Generator(DWVG),and the effects of different height ratios(Rh=0.6,0.8,1,1.2 and 1.4)in delta wing vortex generators,which were not considered in the earlier studies,are *** and exergy analyses are performed to gain maximum *** Reynolds number based on the outlet velocity and hydraulic diameter falls between 4400 and 22000,corresponding to the volume flow rate of 5.21–26.07 m^(3)/*** is observed that the delta wing vortex generators with a higher height ratio yield maximum heat transfer enhancement and overall enhancement *** empirical and numerical findings demonstrate that the exergy and thermal efficiencies decline in a specific *** number,pressure drop,energy,and exergy efficiencies enhance with rising Reynolds number,although the friction coefficient *** maximum heat transfer enhancement is 57%.According to the evaluation of exergy efficiency,the greatest efficiency of 31.2%is obtained at Rh=1.4 and Reynolds number 22000.

关键词： Vortex generators heat transfer augmentation numerical simulation solar air collector empirical height ratio

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An FFT Performance Model for Optimizing General-Purpose Processor Architecture

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Journal of Computer Science & Technology 2011年第5期26卷 875-889页

作者：李玲陈云霁刘道福钱诚胡伟武 Institute of Computing Technology Chinese Academy of Sciences Loongson Technologies corporation Limited

General-purpose processor （GPP） is an important platform for fast Fourier transform （FFT）,due to its flexibility,reliability and *** is a representative application intensive in both computation and memory access,optimizing the FFT performance of a GPP also benefits the performances of many other *** facilitate the analysis of FFT,this paper proposes a theoretical model of the FFT *** model gives out a tight lower bound of the runtime of FFT on a GPP,and guides the architecture optimization for GPP as *** on the model,two theorems on optimization of architecture parameters are deduced,which refer to the lower bounds of register number and memory *** results on different processor architectures （including Intel Core i7 and Godson-3B） validate the performance *** above investigations were adopted in the development of Godson-3B,which is an industrial *** optimization techniques deduced from our performance model improve the FFT performance by about 40%,while incurring only 0.8% additional area ***,Godson-3B solves the 1024-point single-precision complex FFT in 0.368 μs with about 40 Watt power consumption,and has the highest performance-per-watt in complex FFT among processors as far as we *** work could benefit optimization of other GPPs as well.

关键词： fast Fourier transform (FFT) general-purpose processor (GPP) performance prediction model vector unit DMA

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Physical Implementation of the Eight-Core Godson-3B Microprocessor

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Journal of Computer Science & Technology 2011年第3期26卷 520-527页

作者：王茹范宝峡杨梁高燕萍刘动肖斌王江嵋张译夫王宏胡伟武 Institute of Computing Technology Chinese Academy of Sciences Graduate School of Chinese Academy of sciences Loongson Technologies corporation Limited

The Godson-3B processor is a powerful processor designed for high performance servers including Dawning Servers. It offers significantly improved performance over previous Godson-3 series CPUs by incorporating eight CPU cores and vector computing units. It contains 582.6 M transistors within 300 mm2 area in 65 nm technology and is implemented in parallel with full hierarchical design flows. In Godson-3B, advanced clock distribution mechanisms including GALS （Globally Asynchronous Locally Synchronous） and clock mesh are adopted to obtain an OCV tolerable clock network. Custom-designed de-skew modules are also implemented to afford further latency balance after fabrication. The power reduction of Godson- 3B is maintained by MLMM （Multi Level Multi Mode） clock gating and multi-threshold-voltage cells substitution schemes. The highest frequency of Godson-3B is 1.05 GHz and the peak performance is 128 GFlops （double-precision） or 256 GFlops （single-precision） with 40 W power consumption.

关键词： physical implementation hierarchical design flow GALS clock mesh low power

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Orbitronics for energy-efficient magnetization switching

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Science China(Information sciences) 2025年第1期 398-399页

作者： Yuxuan YAO Daoqian ZHU Qingtao XIA Jianing LIANG Yuhao JIANG Zhiyang PENG Jiaxu LI Chen XIAO Renyou XU Wenwen WANG Xiantao SHANG Shiyang LU Dapeng ZHU Hong-Xi LIU Kaihua CAO Weisheng ZHAO Fert Beijing Institute School of Integrated Circuit Science and Engineering Beihang University National Key Lab of Spintronics Institute of International Innovation Beihang University Qingdao Research Institute Beihang University Truth Memory corporation

Spin-orbit torque （SOT）,as a promising writing method for magnetic random-access memory （MRAM）,has garnered widespread interest for over a decade [1].Heavy metals,such as β-W,have been broadly adopted as spin current sources,but suffer from phase change at a limited thickness,resulting in a dramatic reduction of the charge-tospin conversion efficiency θSH[2].The thickness limitation leads to stringent etching conditions and large distribution among devices,posing challenges for simultaneously satisfying SOT efficiency,etching-stop margins,and back-end-ofline （BEOL） compatibility.

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Simulation procedure of unconfined seepage with an inner seepage face in a heterogeneous field

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Science China(Physics,Mechanics & Astronomy) 2013年第6期56卷 1139-1147页

作者： WU MengXi YANG LianZhi YU Ting Institute of Mechanics Chinese Academy of Sciences Hydrochina Chengdu Engineering corporation

An inner seepage face phenomenon is given and a numerical simulation procedure has been *** may appear at the interface of two materials when an unconfined seepage flows from a porous media to a coarser porous media with a higher *** and divergent problems may arise both in a saturated-only and in a variably saturated analysis while an inner seepage face is not simulated with a special *** position of the seepage face is determined during the nonlinear iteration process and the flux of the inner seepage face nodes is transferred to the downstream side *** and efficiency of the procedure are illustrated by the simulation of two dimensional steady state seepage examples of heterogeneous zoned dams which is usually used to validate *** analysis of a three-dimensional earth core rockfill dam is also presented *** procedure can also be applied to general transient seepage problems.

关键词： unconfined seepage inner seepage face finite element method free surface

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The Godson Processors:Its Research,Development,and Contributions

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Journal of Computer Science & Technology 2011年第3期26卷 363-372页

作者：胡伟武高燕萍陈天石肖俊华 Key Laboratory of Computer System and Architecture Chinese Academy of Sciences Loongson Technologies corporation Limited Graduate University of Chinese Academy of sciences

The Godson project with an R＆D history of 10 years is an independent national program of China that aims at developing advanced microprocessor technologies based on fundamental research and commercialization of the chip technology. We will give a comprehensive presentation of the Godson project, including its history, technical roadmaps, and several unique technical merits.

关键词： IT industry CPU research and development Godson microprocessor XPU system on chip

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Design for Testability Features of Godson-3 Multicore Microprocessor

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Journal of Computer Science & Technology 2011年第2期26卷 302-313页

作者：齐子初刘慧李向库胡伟武 Key Laboratory of Computer System and Architecture Chinese Academy of Sciences Institute of Computing Technology Chinese Academy of Sciences Loongson Technologies corporation Limited

This paper describes the design for testability （DFT） challenges and techniques of Godson-3 microprocessor, which is a scalable multicore processor based on the scalable mesh of crossbar （SMOC） on-chip network and targets high-end applications. Advanced techniques are adopted to make the DFT design scalable and achieve low-power and low-cost test with limited IO resources. To achieve a scalable and flexible test access, a highly elaborate test access mechanism （TAM） is implemented to support multiple test instructions and test modes. Taking advantage of multiple identical cores embedding in the processor, scan partition and on-chip comparisons are employed to reduce test power and test time. Test compression technique is also utilized to decrease test time. To further reduce test power, clock controlling logics are designed with ability to turn off clocks of non-testing partitions. In addition, scan collars of CACHEs are designed to perform functional test with low-speed ATE for speed-binning purposes, which poses low complexity and has good correlation results.

关键词： DFT (design for testability) TAM (test access mechanism) multicore processor low power test

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SYNTHESIS AND CHARACTERISTICS OF POLY(ARYLENE ETHER DIKETONE)S

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Chinese Journal of Polymer Science 1998年第4期16卷 316-326页

作者：高雪松卢凤才 Polymer Chemistry Laboratory Chinese Academy of Sciences and China Petro-Chemical Corporation Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

Poly(arylene ether diketone)s were prepared by the aromatic nucleophilic displacement reaction of 4,4'-difluorobenzil with different bisphenols in the presence of anhydrous potassium carbonate in diphenylsulfone at elevated temperature. The polymers obtained had inherent viscosity of 0.51 similar to 0.63 dL/g, and exhibited glass transition temperature ranging from 136 similar to 217 degrees C mainly depending on the bisphenols used in the polymer synthesis. Thermogravimetry of these polymers showed excellent thermal stability, indicating that 10% weight losses of the polymers were observed in the range above 428 degrees C and 438 degrees C in air and nitrogen, respectively. The mechanical properties of these polymers were also described and the permeability of five polymers for H-2, O-2 and N-2 was determined at 30 degrees C.

关键词： poly(arylene ether diketone) thermal behavior high-temperature polymers permeability

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