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Predication of Plastic Flow Characteristics in Ferrite/Pearlite Steel Using a Fern Unit Cell Method

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上海交通大学学报 2004年第Z2期38卷 61-66页

作者： Hong Li Jingtao Han Jing Liu Lv Zhang School of Material sci. & eng. Univ. Of Sci. &Tech. Beijing Beijing100083 China School of Material Sci. & Eng. Univ. Of Sci. &Tech. Beijing Beijing100083 China School of Material Sci. & Eng. Univ. Of Sci. &Tech. Beijing Beijing100083 China School of Material Sci. & Eng. Univ. Of Sci. &Tech. Beijing Beijing100083 China

The flow stress of ferrite/pearlite steel under uni-axial tension was simulated with finite element method (FEM) by applying commercial software MARC/MENTAT. Flow stress curves of ferrite/pearlite steels were calculated based on unit cell model. The effects of volume fraction, distribution and the aspect ratio of pearlite on tensile properties have been investigated.

关键词： ferrite/pearlite steel unit cell flow curve finite element method simulation

D-scheduler:A scheduler in time-triggered distributed system through decoupling dependencies between tasks and messages

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sci.nce China(Technological sci.nces) 2024年第1期67卷 183-196页

作者： YANG TingTing ZHANG YuQi YUE Feng.ai WUNIRI QiQiGe TONG Chao School of Computer sci.nce&eng.neering Beihang UniversityBeijing 100191China State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China National Innovation Center of Intelligent and Connected Vehicles Beijing 100176China

Time-triggered architecture,as a mainstream design of the distributed real-time system,has been successfully applied in the aerospace,automotive and mechanical ***,time-triggered scheduling is a challeng.ng NP-hard *** are few studies that could quickly solve the scheduling problem of large distributed time-triggered *** solve this problem,a communication affinity parameter is defined in this paper to describe the degree of bias of the shaper task towards sending or receiving *** on this,an innovative task-message decoupling model named D-scheduler is built to reduce the computation complexity of the scheduling problem in large-scale ***,we provide mathematical proof that our model is a convex optimization that is easy to solve with existing computational *** experiments substantiate the efficacy of the *** dramatically reduces the scheduling complexity of large-scale real-time systems with a small loss of solving space compared to the federal scheduler.

关键词： time-triggered architecture time-triggered scheduling communication affinity parameter task-message decoupling model

DEFORMATION ENHANCED FERRITE TRANSFORMATION IN PLAIN LOW CARBON STEEL

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Acta Metallurgica Sinica(eng.ish Letters) 2001年第2期14卷 115-121页

作者： Z.Q. Sun, W Y. Yang, A.M. Hu and P. Yang (State Key Laboratory for Advanced Metals and Materials, univ.rsity of sci.nce and Technology beijing, beijing 100083, China) (School of Material sci.nce and eng.neering, univ.rsity of sci.nce and Technology Beijin beijing univ. of sci. and eng. Beijing 100083 China

The microstructure evolution during deformation enhanced transformation of undercooled austenite of a plain low carbon steel has been investigated by means of hot compression simulation experiment under various conditions of strain rate, deformation temperature and strain. The effect of austenite grain size on the strain enhanced ferrite transformation has been studied. The ferrite dynamic recrystallization involved in successive hot deformation has been explored.

关键词： deformation enhanced transformation undercooled austenite.plain low carbon steel microstructure refinement

Exercise Fatigue Monitoring Based on R-Peak Detection Using UNET-TCN

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Journal of beijing Institute of Technology 2024年第4期33卷 337-345页

作者： Xinhua Su Xuxuan Wang Xinxin Ma Schoolof Sports eng.neering Beijing Sport UniversityBeijing100091China

Moderate exercise contributes to health, but excessive exercise may lead to physicalinjury or even endanger life. It is pressing for a device that can detect the intensity of ***, in order to enable real-time detection of exercise intensity and mitigate the risks of harmfrom excessive exercise, a exercise intensity monitoring system based on the heart rate variability(HRV) from electrocardiogram (ECG) signal and linear features from phonocardiogram (PCG)signal is proposed. The main contributions include: First, accurate analysis of HRV is crucial forsubsequent exercise intensity detection. To enhance HRV analysis, we propose an R-peak detectorbased on encoder-decoder and temporal convolutional network (TCN). Experimental resultsdemonstrate that the proposed R-peak detector achieves an F1 score exceeding 0.99 on real high-intensity exercise ECG datasets. Second, an exercise fatigue monitoring system based on multi-sig-nal feature fusion is proposed. Initially, utilizing the proposed R-peak detector for HRV extractionin exercise intensity detection,which outperforms traditional algorithms, with the system achiev-ing a classification performance of 0.933 sensitivity, 0.802 specificity, and 0.960 accuracy. To fur-ther improve the system, we combine HRV with the linear features of PCG. Our exercise intensitydetection system achieves 90.2% specificity, 96.7% recall, and 98.1% accuracy in five-fold cross-vali-dation.

关键词： heart rate variability(HRV) phonocardiogram(PCG) Unet temporal convolutionalnetwork(TCN) machine learning exercise intensity

Magneto-optic Kerr Effect Measurement of TbMn_(6)Sn_(6) at mK Temperature

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Chinese Physics Letters 2024年第4期41卷 159-163页

作者：黄代强汪洋王贺王健刘阳 International Center for Quantum Materials Peking UniversityBeijing 100871China Department of Physics Capital Normal UniversityBeijing 100048China Collaborative Innovation Center of Quantum Matter Beijing 100871China Hefei National Laboratory Hefei 230088China

Novel electron states stabilized by Coulomb interactions attract tremendous interests in condensed matter *** states are studied by corresponding phase transitions occurring at extreme conditions such as mK temperatures and high magnetic *** this work,we introduce a magneto-optical Kerr effect measurement system to comprehensively explore these phases in addition to conventional transport *** system,composed of an all-fiber zero-loop Sagnac interferometer and in situ piezo-scanner inside a dilution refrigerator,operates below 100 m K,with a maximum field of 12 Tesla and has a resolution as small as 0.2μ*** a demonstration,we investigate TbMn_(6)Sn_(6),where the manganese atoms form Kagome lattice that hosts topological non-trivial Dirac *** observed two types of Kerr signals,stemming from its fully polarized ferromagnetic ground state and positive charged carriers within the Dirac-like dispersion.

关键词： interferometer scanner system

PCG-Based Exercise Fatigue Detection Method Using FRFT-Based Fusion Model

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Journal of beijing Institute of Technology 2024年第4期33卷 298-306页

作者： Xinxin Ma Xinhua Su Huanmin Ge Schoolof Sports eng.neering Beijing Sport UniversityBeijing 100084China.

Accurate detection of exercise fatigue based on physiological signals is vital for reason-able physical *** a non-invasive technology,phonocardiogram(PCG)signals possess arobust capability to reflect cardiovascular information,and their data acquisition devices are *** this study,a novel hybrid approach of fractional Fourier transform(FRFT)com-bined with linear and discrete wavelet transform(DWT)features extracted from PCG is proposedfor PCG multi-class *** proposed system enhances the fatigue detection performanceby combining optimized FRFT features with an effective aggregation of linear features and *** FRFT technique is employed to convert the 1-D PCG signal into 2-D image which issent to a pre-trained convolutional neural network structure,called *** features from theVGG-16 were concatenated with the linear and DWT features to form fused *** fusedfeatures are sent to support vector machine(SVM)to distinguish six distinct fatigue ***-mental results demonstrate that the proposed fused features outperform other feature combinationssignificantly.

关键词： exercise fatigue phonocardiogram(PCG) fractional Fourier transform(FRFT) dis-crete wavelet transform(DWT) future fusion

Prediction of chemical short-range order in high-/medium-entropy alloys

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Journal of Materials sci.nce & Technology 2024年第2期169卷 115-123页

作者： Pei-Yu Cao Jing Wang Ping Jiang Yun-Jiang Wang Fu-Ping Yuan Xiao-Lei Wu State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of ScienceBeijing 100190China School of eng.neering sci.nce University of Chinese Academy of SciencesBeijing 100049China

Chemical short-range orders(CSROs),as the built-in sub-nanoscale entities in a high-/medium-entropy alloy(H/MEA),have aroused an ever-increasing *** multi-principal elements in an H/MEA to form a complex concentrated solution,a variety of sub-systems of species exist to induce the metastable ordered compounds as candidates for ultimate *** issues remain pending on the origin of CSROs as to how to judge if CSRO will form in an H/MEA and particularly,what kind of CSROs would be stably produced if there were multiple ***,the first-principles method,along with the proposed local formation energy calculation in allusion to the atomic-scale chemical heterogeneities,is used to predict the CSRO formation based on the mechanical stability,thermodynamic formation energy,and electronic *** simulations are detailed in an equiatomic ternary VCoNi MEA with three kinds of potential compounds,i.e.,L1_(1),L1_(2),and B2,in the face-centered cubic *** turns out that L1_(1)is stable but hard to grow up so as to become the final CSRO.L1_(1)is further predicted as CSROs in CrCoNi,but unable to form in FeCoNi and CrMnFeCoNi *** predictions are consistent with the experimental *** findings shed light on understanding the formation of *** method is applicable to other H/MEAs to design and tailor CSROs by tuning chemical species/contents and thermal processing for high performance.

关键词： Short-range order High-entropy alloy Microstructure First-principles calculation Gibbs free energy Local electronic density of states

Molecular Dynamics Simulation and Experimental Proof of Hydrogen-enhanced Dislocation Emission in Nickel

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Journal of univ.rsity of sci.nce and Technology beijing 2002年第1期9卷 59-64页

作者： Zhongji Li, Jinxu Li, Wuyang Chu, Hui Liu, Lyie Qiao, Materials sci.nce and eng.neering School, univ.rsity of sci.nce and Technology beijing. beijing 100083, China E-mail: lqiao@*** Mat. sci. and eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

A quasi three dimensions molecular dynamic method was used to simulate the effect of hydrogen on dislocation emission and crack propagation in nickel. In situ observation in a transmission electron microscope (TEM) was used to confirm the simulation results. The simulation result indicated that hydrogen solubilized in nickel decreased the critical stress intensity for the dislocation emission, i.e., hydrogen enhanced dislocation emission. In situ observation in TEM showed that hydrogen enhanced dislocation emission and motion before the initiation of hydrogen-induced crack.

关键词： nickel molecular dynamics simulation hydrogen dislocation emission TEM

Chemico-biological conversion of carbon dioxide

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Journal of Energy Chemistry 2024年第2期89卷 371-387,I0009页

作者： Liangwei Hu Junzhu Yang Qi Xia Jin Zhang Hongxin Zhao Yuan Lu Zhejiang Province Key Laboratory of Plant Secondary Metabolism and Regulation College of Life Sciences and MedicineZhejiang Sci-Tech UniversityHangzhou 310018ZhejiangChina Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084China Department of Chemical eng.neering Tsinghua UniversityBeijing 100084China College of Biological and Chemical eng.neering Jiaxing UniversityJiaxing 314000ZhejiangChina

The unabated carbon dioxide(CO_(2))emission into the atmosphere has exacerbated global climate change,resulting in extreme weather events,biodiversity loss,and an intensified greenhouse *** address these challeng.s and work toward carbon(C)neutrality and reduced CO_(2)emissions,the capture and utilization of CO_(2)have become imperative in both sci.ntific research and *** cutting-edge approach to achieving efficient catalytic performance involves integrating green bioconversion and chemical *** innovative strategy offers several advantages,including environmental friendliness,high efficiency,and *** study provides a comprehensive review of existing technical routes for carbon sequestration(CS)and introduces two novel CS pathways:the electrochemicalbiological hybrid and artificial photosynthesis *** also thoroughly examines the synthesis of valuable Cnproducts from the two CS systems employing different catalysts and *** both systems heavily rely on electron transfer,direct and mediated electron transfer has been discussed and summarized in ***,this study explores the conditions suitable for different catalysts and assesses the streng.hs and weaknesses of *** also explored the biocompatibility of the electrode materials and developed novel *** materials were specifically eng.neered to combine with enzymes or microbial cells to solve the biocompatibility problem,while improving the electron transfer efficiency of ***,this review summarizes the relevant systems developed in recent years for manufacturing different products,along with their respective production efficiencies,providing a solid database for development in this *** novel chemical-biological combination proposed herein holds great promise for the future conversion of CO_(2)into advanced organic ***,it offers exciting prospects for utilizing CO_(2)in synthesizing

关键词： Carbon dioxide Bioelectric synthesis Artificial photosynthesis Synthetic product