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Fast division-free parallel structure for convolution perfectly matched layer in finite difference time domain method

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The Journal of China Universities of Posts and Telecommunications 2015年第1期22卷 72-76,82页

作者： Bai Bing Niu Zhongqi Niu Yi Wei Bing Zhao Gang School of Electronic Engineering Xidian University School of Physics and Optoelectronic Engineering Xidian University

Parallel acceleration of convolution perfectly matched layer （CPML） algorithm suffers from massive division operation which is widely accepted as one of the most expensive operations for the equipment such as graphic processing unit （GPU）, field programmable gate array （FPGA） etc. In pursuit of higher efficiency and lower power consumption, this article revisited the CPML theory and proposed a new fast division-free parallel CPML structure. By optimally rearranging the CPML inner iteration process, all the division operators can be eliminated and replaced by recalculating the related field updating coefficients offline. Experiments show that the proposed division-free structure can save more than 50% arithmetic instructions and 25% execution time of the traditional parallel CPML structure without any accuracy loss.

关键词： division elimination convolution perfectly matched layer finit difference time domain parallel computing graphic processing unit

Effect of Continuous Annealing on Microstructure and Bake Hardening Behavior of Low Carbon Steel

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Journal of Iron and Steel Research International 2015年第2期22卷 163-170页

作者： Chun-fu KUANG Jian WANG Jun LI Shen-gen ZHANG Hua-fei LIU Hong-lin YANG School of Materials science and Engineering University of Science and Technology Beijing Research Institute Baoshan Iron & Steel Co.Ltd.

The influences of the heating rate, annealing temperature and soaking time during continuous annealing on the microstructure evolution and bake hardening behavior of the low carbon steel were investigated. After 2% pres- training, bake treatment （180 ℃ × 20 min） was carried out to measure BH （bake hardening） values. The results showed that, with the increase of the annealing temperature, the grain size increased except for annealing in the in- tercritical region. Furthermore, the BH value increased and the mean grain size reduced with increasing the heating rate from 5 to 80 ℃/s. The BH value was very low before complete recrystallization. After a significant decrease from 630 to 720 ℃ , the BH value enhanced when the steel was annealed at 750 ℃. With the increase of the soaking time from 20 to 100 s, the BH value reduced linearly due to the segregation of solute C atoms.

关键词： continuous annealing low carbon steel bake hardening microstructure BH value

Microstructure and mechanical properties of TiAl/TiAl joints brazed with a newly developed Ti–Ni–Nb–Zr quaternary filler alloy

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Progress in natural science:Materials International 2022年第6期32卷 758-768页

作者： H.S.Ren Y.L.Shang X.Y.Ren Y.J.Jing H.P.Xiong Y.Y.Cheng Welding and Plastic Forming Division Beijing Institute of Aeronautical Materials

A novel Ti-Ni-Nb-Zr quaternary filler alloy with the composition of Ti-(19～25)Ni-(15～25)(Nb+Zr)(wt.%) was *** filler alloy was composed of(Ti,Nb)ss,(Ti,Zr,Nb)ss+(Ti,Zr)2Ni,α-Ti and Ti2Ni *** was fabricated into filler foil with a thickness of about 45 μm by a rapid solidification *** results indicate that the liquidus temperature of the Ti-Ni-Nb-Zr brazing alloy was about 978℃,and the brazing alloy presented excellent wettability on TiAl *** TiAl joint mainly consisted of β/B2 phase,Ti2Al,Ti2AlNi and α2-Ti3Al *** diffusion of Al atom from base metal to brazed seam led to the formation of Ti2Al and *** that no previously references on XRD pattern of Ti2AlNi compound can be found,Ti2AlNi cast alloy specimen was specially prepared and XRD peaks were specially *** micro-hardness and bending strength tests of the Ti2AlNi phase were carried out,and the results were 761 HV and 192 MPa,*** brazing parameters of 1010 ℃/10 min offered the joint shear strength of 280 MPa at room temperature,and the joints exhibited tensile strength of 372 MPa at room temperature and 340 MPa at 750 ℃,indicating that the newly developed filler alloy could offer a stable high-temperature strength.

关键词： TiAl Brazing Filler alloy Microstructure Mechanical properties

Identification of close relationship between atmospheric oxidation and ozone formation regimes in a photochemically active region

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Journal of Environmental sciences 2021年第4期33卷 373-383页

作者： Kaihui Zhao Huihong Luo Zibing Yuan Danni Xu Yi Du Shu Zhang Yuqi Hao Yonghua Wu Jianping Huang Ying Wang Rongsheng Jiang School of Environment and Energy South China University of TechnologyGuangzhou 510006China The City College of New York(CCNY) New YorkNY 10031USA NOAA–Cooperative science Center for Earth System sciences and Remote Sensing Technologies New YorkNY 10031USA NOAA-NCEP Environmental Modeling Center and IM System Group Inc. College ParkMD 720740USA Yale-NUIST Center on Atmospheric Environment Nanjing University of Information Science&TechnologyNanjing 210044China Xianyang Meteorological Bureau Xianyang 712000China Climate Environment and Sustainability CenterNanjing University of Information Science and TechnologyNanjing 210044China

Understanding ozone(O_(3))formation regime is a prerequisite in formulating an effective O_(3)pollution control *** indicator is a simple and direct method in identifying O_(3)formation *** used indicators are derived from observations,whereas the role of atmospheric oxidation is not in consideration,which is the core driver of O_(3)***,it may impact accuracy in signaling O_(3)formation *** this study,an advanced three-dimensional numerical modeling system was used to investigate the relationship between atmospheric oxidation and O_(3)formation regimes during a long-lasting O_(3)exceedance event in September 2017 over the Pearl River Delta(PRD)of *** discovered a clear relationship between atmospheric oxidative capacity and O_(3)formation *** eastern PRD,O_(3)formation was mainly in a NO x-limited regime when HO_(2)/OH ratio was higher than 11,while in a VOC-limited regime when the ratio was lower than *** central and western PRD,an HO_(2)/OH ratio higher than 5 and lower than 2 was indicative of NO x-limited and VOC-limited regime,*** contribution,including horizontal transport and vertical transport,may pose uncertainties on the indication of O_(3)formation regime by HO_(2)/OH *** comparison with other commonly used photochemical indicators,HO_(2)/OH ratio had the best performance in differentiating O_(3)formation *** study highlighted the necessities in using an atmospheric oxidative capacity-based indicator to infer O_(3)formation regime,and underscored the importance of characterizing behaviors of radicals to gain insight in atmospheric processes leading to O_(3)pollution over a photochemically active region.

关键词： Atmospheric oxidation O_(3)formation regimes WRF-CMAQ Photochemically active region

Research on Adaptive TSSA-HKRVM Model for Regression Prediction of Crane Load Spectrum

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Computer Modeling in Engineering & sciences 2023年第9期136卷 2345-2370页

作者： Dong Qing Qi Song Shuangyun Huang Gening Xu College of Mechanical Engineering Taiyuan University of Science and TechnologyTaiyuan030024China Zhuzhou Tianqiao Crane Co. Ltd.Zhuzhou412001China

For the randomness of crane working load leading to the decrease of load spectrum prediction accuracy with time,an adaptive TSSA-HKRVM model for crane load spectrum regression prediction is *** heterogeneous kernel relevance vector machine model(HKRVM)with comprehensive expression ability is established using the complementary advantages of various kernel *** combination strategy consisting of refraction reverse learning,golden sine,and Cauchy mutation+logistic chaotic perturbation is introduced to form a multi-strategy improved sparrow algorithm(TSSA),thus optimizing the relevant parameters of *** adaptive updatingmechanismof the heterogeneous kernel RVMmodel under themulti-strategy improved sparrow algorithm(TSSA-HKMRVM)is defined by the sliding window design *** on the sample data of the measured load spectrum,the trained adaptive TSSA-HKRVMmodel is employed to complete the prediction of the crane equivalent load *** this method toQD20/10 t×43m×12mgeneral bridge crane,the results show that:compared with other prediction models,although the complexity of the adaptive TSSA-HKRVMmodel is relatively high,the prediction accuracy of the load spectrum under long periods has been effectively improved,and the completeness of the load information during thewhole life cycle is relatively higher,with better applicability.

关键词： Heterogeneous kernel function RVM TSSA adaptive update mechanism equivalent load spectrum

A Review on SOM-LES of Turbulent Two-Phase Combustion

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Journal of Thermal science 2023年第6期32卷 2215-2221页

作者： ZHOU Lixing LIU Yang WANG Fang HU Liyuan LI Ke LUO Kun Department of Engineering Mechanics Tsinghua UniversityBeijing100084China School of Energy and Power Engineering Beihang UniversityBeijing100191China School of Energy&Environmental Engineering Inner Mongolia University of Science and TechnologyBaotou014010China State Key Laboratory of Clean Combustion Zhejiang UniversityHangzhou310027China

Turbulent two-phase combustion is widely encountered in spray and pulverized-coal combustors,and large-eddy simulation(LES)becomes a powerful CFD method for its simulation,because LES can give unsteady flame structures and more reasonable statistical results than Reynolds-averaged *** combustion models in LES either lack of generality or are computationally too expensive.A statistical moment model based on the idea of turbulence modeling called“second-order moment(SOM)combustion model”was developed by the present authors for LES of two-phase *** this paper,a review is given on our published research results for SOM-LES of two-phase combustion,including the description of the SOM-LES model,its application,validation of statistical results by experiments,as well as the phenomena obtained by instantaneous results.

关键词： two-phase combustion large-eddy simulation second-order moment model

Spray Deposition Behavior and Numerical Simulation of Growth of Tubular Preform in Spray Forming Process

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Journal of Iron and Steel Research International 2012年第2期19卷 28-35页

作者： XIANG Jin-zong ZHANG Yin FAN Wen-jun WANG Ping HE You-duo Inner Mongolia Key Laboratory for Utilization of Bayan Obo Multi-Metallic Resources： Elected State KeyLaboratory Inner Mongolia University of Science and Technology Baotou 014010 Inner Mongolia China Anhui Shoukuang-Dachang Metal Materials Co Ltd Luran 237400 Anhui China

Analysis on the deposition behavior of spray on deposition surface was made and an optimization method for the movement parameters （u, ω） of substrate was obtained. Simultaneously, a mathematical model of growth of tubular preform, specifically aimed at the kind of atomizer that is fixed and with a tilt angle was established. By in- tegrating the optimization method and the mathematical model, the growth process and shape of preform were simu- lated. The results show that the tilt angle of atomizer plays an important role on the dimensions and shapes of tubular preforms and it can provide a guidance for the development of spray forming equipment.

关键词： spray deposition behavior parameters optimization tubular preform~ growth process

Analysis of Solidification of High Manganese Steels Using Improved Differential Thermal Analysis Method

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Journal of Iron and Steel Research International 2015年第8期22卷 709-714页

作者： Chang-ling ZHUANG Jian-hua LIU Christian BERNHARD Peter PRESOLY Engineering Research Institute University of Science and Technology Beijing Chair of Metallurgy Montanuniversitat Leoben

High manganese steels can damage the differential thermal analysis （DTA） instrument due to the manganese evaporation during high temperature experiments. After analyzing the relationship between residual oxygen and manganese evaporation, tanta- lum metal was employed to modify the crucible of DTA, and zirconium getter together with strict gas purification measures were applied to control the volatilization of manganese. By these modifications, problems of thermocouple damage and DTA instrument contamination were successfully resolved. Cobalt samples were adopted to calibrate the accuracy of DTA instruments under the same trial condition of high manganese steel samples, and the detection error was confirmed to be less than 1 ℃. Liquidus and soli- dus temperatures of high Mn steels were measured by improved DTA method. It was found that the liquidus temperatures of sam- ples tested by experiments increased linearly with the heating rates. To eliminate the effects of the heating rate, equilibrium liquidus temperature was determined by fitting the liquidus temperatures at different heating rates, and referred as real liquidus temperature. No clear relationship between solidus temperatures and heating rates was found, and the solidus temperature was finally set as the average value of several experimental data.

关键词： DTA high manganese steel solidification liquidus temperature solidus temperature

Quantitative study of dimensional stability mechanism and microstructure evolution during precipitation process of 2024Al alloy

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Journal of Materials science & Technology 2021年第31期90卷 85-94页

作者： Youfang Cao Longtao Jiang Deng Gong Guoqin Chen Ziyang Xiu Yangming Cheng Xiufang Wang Gaohui Wua School of Materials science and Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Advanced Welding Production Technology Harbin Institute of TechnologyHarbin 150001China Shanghai Institute of Microsystem and Information Technology Chinese Academy of SciencesShanghai 200050China

In this paper,we were devoted to quantitatively analyzing the dimensional change of 2024 Al alloy during the aging *** of precipitates have been defined and the corresponding volume fraction has been measured with Transmission Electron Microscopy(TEM)and Three-Dimensional Atom Probe Tomography(3 D-APT).Guinier-Preston-Bagaryatsky(GPB)zone(0.86 vol.%)was found after aging for 8 *** zone(0.17 vol.%)and S'phase(1.02 vol.%)was found after aging for 24 *** reduced dimensional change was attributed to the reduction of matrix lattice *** to the initial supersaturated solid solution state,the lattice strain of-2.79×10^(-5)and-5.16×10^(-5)was produced after 8 h and 24 h aging *** difference of the lattice parameters between the precipitates and matrix was also considered.A model was established to quantitatively describe the relationship between the precipitation process and dimensional change of 2024 Al alloy.

关键词： Aluminum alloy Aging Atom probe tomography(APT) Dimensional stability Precipitate