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Research Square 2021年

作者： Luo, Shiyuan Jiang, Yongxin Zhang, Po Yu, Fengping Liu, Siwen Key Laboratory of Metallurgical Equipment and Control Technology Ministry of Education School of Machinery and Automation Wuhan University of Science and Technology Wuhan430081 China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering School of Machinery and Automation Wuhan University of Science and Technology Wuhan430081 China Technology Center Wuxi Turbine Blade Co. Ltd. Wuxi214174 China China Railway Siyuan Survey and Design Group Co. Ltd. Wuhan430063 China

Friction conditions significantly impact the temperature and phases of titanium forged parts, further directly affecting the microstructures and mechanical properties of final parts. In this paper, a 2D simplified FE model combined with phase transition equations is developed to simulate Ti-6Al-4V drum forging procedure. Then, friction effects on the temperature and phases of the forged drum are numerically analyzed and verified by experiments. Results indicate that unlike little influence on α+β phase, improving friction obviously decreases the general levels of temperature and β phase and increases the homogeneities of α and β phases within the forged drum, which are associated with cooling rates and the heating effects of friction and deformation. © 2021, CC BY.

关键词： Titanium alloys

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Discovery of an Orally Active Small-Molecule Tumor Necrosis Factor-α Inhibitor

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Journal of Medicinal Chemistry 2020年第15期63卷 8146-8156页

作者： Sun, Weiguang Wu, Yanli Zheng, Mengzhu Yang, Yueying Liu, Yang Wu, Canrong Zhou, Yirong Zhang, Yonghui Chen, Lixia Li, Hua Hubei Key Laboratory of Natural Medicinal Chemistry and Resource Evaluation School of Pharmacy Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China Wuya College of Innovation Key Laboratory of Structure-Based Drug Design and Discovery Ministry of Education Shenyang Pharmaceutical University Shenyang 110016 China

Tumor necrosis factor α (TNF-α) is an important therapeutic target for rheumatoid arthritis, inflammatory bowel disease, and septic hepatitis. In this study, structure-based virtual ligand screening combined with in vitro and in vivo assays were applied. A lead compound, benpyrine, could directly bind to TNF-α and block TNF-α-trigged signaling activation. Furthermore, the endotoxemic murine model showed that benpyrine could attenuate TNF-α-induced inflammation, thereby reducing liver and lung injury. Meanwhile, administration of benpyrine by gavage significantly relieved the symptoms of collagen-induced arthritis and imiquimod-induced psoriasiform inflammation in mice. Thus, our study discovered a novel, highly specific, and orally active small-molecule TNF-α inhibitor that is potentially useful for treating TNF-α-mediated inflammatory and autoimmune disease. © 2020 American Chemical Society.

关键词： Anatomy Serum Rodent models Peptides and proteins Inflammation

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Violation of the T^(−1) Relationship in the Lattice Thermal Conductivity of Mg_(3)Sb_(2) with Locally Asymmetric Vibrations

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Research 2020年第1期2020卷 750-759页

作者： Yifan Zhu Yi Xia Yancheng Wang Ye Sheng Jiong Yang Chenguang Fu Airan Li Tiejun Zhu Jun Luo Christopher Wolverton GJeffrey Snyder Jianjun Liu Wenqing Zhang State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of SciencesShanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Materials Genome Institute Shanghai UniversityShanghai 200444China Department of Materials Science and Engineering Northwestern UniversityIL 60208USA Max Planck Institute for Chemical Physics of Solids Dresden 01187Germany State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Department of Physics and Shenzhen Institute for Quantum Science&Engineering Southern University of Science and TechnologyShenzhen 518055China Guangdong Provincial Key Lab for Computational Science and Materials Design and Shenzhen Municipal Key Lab for Advanced Quantum Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

Most crystalline materials follow the guidelines of T^(-1) temperature-dependent lattice thermal conductivity(κ_(L))at elevated ***,we observe a weak temperature dependence ofκL in Mg_(3)Sb_(2),T^(-0:48) from theory and T-0:57 from measurements,based on a comprehensive study combining ab initio molecular dynamics calculations and experimental measurements on single crystal Mg_(3)Sb_(2).These results can be understood in terms of the so-called“phonon renormalization”effects due to the strong temperature dependence of the interatomic force constants(IFCs).The increasing temperature leads to the frequency upshifting for those low-frequency phonons dominating heat transport,and more importantly,the phononphonon interactions are ***-depth analysis reveals that the phenomenon is closely related to the temperature-induced asymmetric movements of Mg atoms within MgSb_(4) *** increasing temperature,these Mg atoms tend to locate at the areas with relatively low force in the force profile,leading to reduced effective 3^(rd)-order *** locally asymmetrical atomic movements at elevated temperatures can be further treated as an indicator of temperature-induced variations of IFCs and thus relatively strong phonon *** present work sheds light on the fundamental origins of anomalous temperature dependence of κ_(L) in thermoelectrics.

关键词： phonon Conductivity Locally

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A one-dimensional hydro-sediment-morphodynamic model for the changjiang waterway 22

A one-dimensional hydro-sediment-morphodynamic model for the...

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22nd Congress of the International Association for Hydro-Environment Engineering and Research-Asia Pacific Division: Creating Resilience to Water-Related Challenges, IAHR-APD 2020

作者： Xia, Chunchen Liang, Hui Cao, Zhixian Peng, Songbai Li, Youwei Liu, Qifeng Zhang, Wei School of Civil Engineering and Architecture Zhejiang University of Technology Hangzhou China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan China Changjiang Waterway Institute of Planning and Design Wuhan China

The Changjiang (Yangtze River) is one of the longest rivers in the world and plays a crucial role in waterborne freight in China. The waterway conditions in the middle and lower Yangtze River may not well meet the increasingly demanding requirements of cost-effective navigation in line with the rapid economic development in the region. Quantitative understanding of the water flow, sediment transport and bed evolution is essential for the regulation and maintenance of the waterway, especially since the Three-Gorges Reservoir was put into operation. One-dimensional (1D) modelling is one of the most viable approaches to enhancing the understanding of the hydro-sediment-morphodynamic processes. Yet previous 1D models are simplified, mostly based on rather crude assumptions (especially the quasi-steady flow assumption), of which the effects have so far remained insufficiently understood. Here, a physically-based 1D numerical model is presented, which explicitly incorporates the interactions between the flow, sediment transport and morphological evolution, and features a wide application in natural rivers with unsteady flows and non-uniform sediment transport. The governing equations are numerically solved using the shock-capturing finite volume method with the HLLC approximate Riemann solver for the flow equations and SLIC approximate Riemann solver for the sediment equation respectively. The model is benchmarked against a spectrum of test cases, and then applied to the reach from Yichang to Gong'an in the middle Changjiang Waterway. It shows that the model is able to successfully resolve the propagations of flow and sediment transport and reveals the influences of the discharge in Yichang on the water levels downstream. The present work facilitates a viable and promising approach to the understanding of the Changjiang Waterway, in support of its regulation and management. © 2020 22nd Congress of the International Association for Hydro-Environment Engineering and Researc

关键词： Finite volume method

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Experimental Study on the Zebra Crossing Behavior of Mixed Bicycles and Pedestrians

SSRN

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SSRN 2022年

作者： Ma, Jian Wang, Qiao Chen, Juan Jiang, Rui Song, Weiguo Li, Ruoyu Lian, Liping School of Transportation and Logistics National Engineering Laboratory of Integrated Transportation Big Data Application Technology National United Engineering Laboratory of Integrated and Intelligent Transportation Southwest Jiaotong University Chengdu610031 China Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University Chengdu610031 China Key Laboratory of Transport Industry of Big Data Application Technologies for Comprehensive Transport Ministry of Transport Beijing Jiaotong University Beijing100044 China State Key Laboratory of Fire Science University of Science and Technology of China Hefei230027 China School of Urban Planning and Design Peking University Shenzhen Graduate School School of Architectural Engineering Shenzhen Polytechnic Shenzhen518055 China

Slow transportation mode, consisting of walking and cycling, plays an important role in urban traffic system. Based on the fact that bicycles and pedestrians often share the common road facility, we conducted bicycle-pedestrian mixed flow experiments to investigate the interaction effect among individuals in a 10 m-long, 3 m-wide passageway, mimicking the zebra crossing area. The goal is to explore the influence of bicycles proportion ( p ) on traffic efficiency and investigate the spatial distribution of agents in the mixed flow. Our analyses showed that the increase of bicycle proportion results in longer passing time and less travel time because of large personal space requirements of cyclists. When the bicycle proportion is small or large, the majority pedestrians (bicycles) were divided into several parts by minor bicycles (pedestrians) along the motion direction. We also recorded the following- and lateral- distance between two nearest individuals to calculate the theoretical formula of the passing time for unidirectional bicycle-pedestrian mixed flow based on the existing formula. Comparing the passing time between numerical calculation and experimental data, the effect coefficients for bicycle and pedestrian were obtained. Focusing on the overtaking bicycles, the through gap, lateral and headway distance that decide the overtaking behavior were analyzed. These findings are the first step toward the development of bicycle-pedestrian mixed flow on zebra crossing, which is contribute to provide practical implications for the planning and design of bicycle and pedestrian shared infrastructures. © 2022, The Authors. All rights reserved.

关键词： Travel time

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Impact Fatigue Life Assessment of Steam Pipeline Based on Transient Analysis

Impact Fatigue Life Assessment of Steam Pipeline Based on Tr...

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Electrical Engineering and Automation (IFEEA), International Forum on

作者： Lao Xingsheng Liu Yong Lin Yuansheng Bai Fan Science and Technology on Thermal Energy and Power Laboratory Wuhan Second Ship Design and Research Institute Wuhan China Wuhan University of Science and Technology Wuhan China

ISBN: (数字)9781728196275

ISBN: (纸本)9781728196282

Fatigue life of high energy steam pipelines under shock loads is estimated based on static load, modal and transient response analysis. The time domain stress curve of pipelines under shock is obtained as the stress spectrum input for pipeline fatigue life prediction. The nCode fatigue analysis software is employed in the study cooperated with the impact fatigue damage model. The results show that the pipeline will experience multiple stress cycles under one impact load, and the maximum stress value exceeds 11% of the yield limit of the material. The impact fatigue life of the pipeline under transverse impact is 1.16×10 5 times. The maximum stress response of the pipe occurs after the forward triangular wave of the impact input and within the reverse triangular wave. The fixed end, elbow and tee of the pipeline are the stress concentration areas of the steam pipelines with the fatigue life of about 4×10 4 times.

关键词： Transient response Electric shock Pipelines Fatigue Time-domain analysis Elbow Stress

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Improvements of the CMFD acceleration capability of OpenMOC

Improvements of the CMFD acceleration capability of OpenMOC

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2019 International Conference on Mathematics and Computational Methods Applied to Nuclear science and Engineering, M and C 2019

作者： Wu, Wenbin Giudicelli, Guillaume Smith, Kord Forget, Benoit Yao, Dong Luo, Qi Department of Nuclear Science and Engineering Massachusetts Institute of Technology 77 Massachusetts Ave CambridgeMA02139 United States Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China NO. 328 Section 1 Changshun Ave Shuangliu District Chengdu Sichuan Province610213 China

ISBN: (纸本)9780894487699

Due to its computational efficiency and geometrical flexibility, the Method of Characteristics (MOC) has been widely used for light water reactor lattice physics analysis. Usually acceleration methods are necessary for MOC to achieve acceptable convergence on practical reactor physics problems. Among them, Coarse Mesh Finite Difference (CMFD) is very popular and can drastically reduce the number of transport iterations. In OpenMOC, CMFD acceleration was implemented but had the limitation of supporting only a uniform CMFD mesh, which would often lead to splitting MOC source regions, thus creating an unnecessary increase in computation and memory use. In this study, CMFD acceleration with a nonuniform Cartesian mesh is implemented into OpenMOC. We also propose a quadratic fit based CMFD prolongation method in the axial direction to further improve the acceleration when multiple MOC source regions are contained in one CMFD coarse cell. Numerical results are presented to demonstrate the improvement of the CMFD acceleration capability in OpenMOC in terms of both efficiency and stability. © 2019 American Nuclear Society. All rights reserved.

关键词： Acceleration

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Experimental Study on the Zebra Crossing Behavior of Mixed Bicycles and Pedestrians

SSRN

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SSRN 2022年

关键词： Travel time

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Reconfiguration of Non-crossing Spanning Trees

arXiv

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arXiv 2022年

作者： Aichholzer, Oswin Ballinger, Brad Biedl, Therese Damian, Mirela Demaine, Erik D. Korman, Matias Lubiw, Anna Lynch, Jayson Tkadlec, Josef Uno, Yushi University of Technology Graz Austria Cal Poly Humboldt United States University of Waterloo Canada Villanova University United States MIT Computer Science and Artificial Intelligence Laboratory United States Siemens Electronic Design Automation United States Harvard Unversity United States Osaka Metropolitan University Japan

For a set P of n points in the plane in general position, a non-crossing spanning tree is a spanning tree of the points where every edge is a straight-line segment between a pair of points and no two edges intersect except at a common endpoint. We study the problem of reconfiguring one non-crossing spanning tree of P to another using a sequence of flips where each flip removes one edge and adds one new edge so that the result is again a non-crossing spanning tree of P. There is a known upper bound of 2n − 4 flips [Avis and Fukuda, 1996] and a lower bound of 1.5n − 5 flips. We give a reconfiguration algorithm that uses at most 2n − 3 flips but reduces that to 1.5n − 2 flips when one tree is a path and either: the points are in convex position;or the path is monotone in some direction. For points in convex position, we prove an upper bound of 2d − Ω(log d) where d is half the size of the symmetric difference between the trees. We also examine whether the happy edges (those common to the initial and final trees) need to flip, and we find exact minimum flip distances for small point sets using exhaustive search. Copyright © 2022, The Authors. All rights reserved.

关键词： Machine learning

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Neural Network-Cascade UDE Based Tracking Control of Leader-Follower Agents with Compound Uncertainties

Neural Network-Cascade UDE Based Tracking Control of Leader-...

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Computers and Automation (CompAuto), International Conference on

作者： Tong Li Weihao Li Zhiqiang Li Mengji Shi Boxian Lin Zixuan Liu AVIC Chengdu Aircraft Design and Research Institute Chengdu China Aircraft Swarm Intelligent Sensing and Cooperative Control Key Laboratory of Sichuan Province University of Electronic Science and Technology of China Chengdu China

ISBN: (纸本)9781665423724

This paper concerns with the multi-agent distributed leader-follower tracking control problems in the presence of compound uncertainties. These unknown time-varying parts not only lie in the both integral units of the second-order follower dynamics, but also show up in the leader’s kinematics. A cascade uncertainty and disturbance estimator (CUDE) based backstepping controller is designed for the followers, which is capable of handling the model uncertainties and input disturbances that respectively appearing in their first-and second-order integral units. However, UDE based methods require accurate modeling of the control system, while the leader is not controllable. Thus, for the leader, the uncertain parts are compensated by constructing a neural network (NN) estimation mechanism. Adaptive estimation parameters are designed according to Lyapunov stability theories to enhance the robustness of the system. The combination of NN and CUDE requires less computational resource than conventional NN-based methods while enabling a valuation of the uncertainty in the leader’s equation. Finally, a numerical simulation is conducted to verify the effectiveness of the control scheme.

关键词： Adaptation models Uncertainty Artificial neural networks Switches Numerical simulation Control systems Robustness

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