Mechanochemical reactions of GaN-Al_2O_3 interface at the nanoasperity contact: Roles of crystallographic polarity and ambient humidity
作者：
Guo, Jian;Gao, Jian;Xiao, Chen;Chen, Lei;Qian, Linmao
期刊：
摩擦(英文) ,2022年10(7):1005-1018 ISSN：2223-7690
通讯作者：
Xiao, Chen(xiaochenswjtu93@gmail.com);Chen, Lei(chenlei@swjtu.edu.cn)
作者机构：
[Guo, Jian] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Chen, Lei; Qian, Linmao; Gao, Jian; Xiao, Chen] Southwest Jiaotong Univ, Tribol Res Inst, State Key Lab Tract Power, Chengdu 610031, Peoples R China.;[Xiao, Chen] Adv Res Ctr Nanolithog ARCNL, Sci Pk 106, NL-1098XG Amsterdam, Netherlands.;[Chen, Lei; Qian, Linmao] Southwest Jiaotong Univ, Technol & Equipment Rail Transit Operat & Mainten, Chengdu 610031, Peoples R China.
通讯机构：
[Chen Xiao; Lei Chen] T;Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, China<&wdkj&>Advanced Research Center for Nanolithography (ARCNL), Amsterdam, The Netherlands<&wdkj&>Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, China<&wdkj&>Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province, Southwest Jiaotong University, Chengdu, China
关键词：
crystallographic polarity;ambient humidity;mechanochemical removal;GaN-Al2O3 interface
摘要：
Mechanochemical reactions of the GaN-Al2O3 interface offer a novel principle for scientific and technological merits in the micro-/nano-scale ultra-precision surface machining. In this work, the mechanochemical reactions on Ga- and N-faced GaN surfaces rubbed by the Al2O3 nanoasperity as a function of the environmental humidity were investigated. Experimental results indicate that the N-face exhibits much stronger mechanochemical removal over the relative humidity range of 20%–80% than the Ga-face. Increasing water molecules in environmental conditions significantly promotes the interfacial mechanochemical reactions and hence accelerates the atomic attrition on N-face. The hypothesized mechanism of the selective water-involved mechanochemical removal is associated with the dangling bond configuration, which affects the mechanically-stimulated chemical reactions via altering the activation energy barrier to form the bonding bridge across the sliding interface. These findings can enrich the understanding of the underlying mechanism of mechanochemical reactions at GaN-Al2O3 interface and a broad cognition for regulating the mechanochemical reactions widely existing in scientific and engineering applications. [Figure not available: see fulltext.]. © 2021, The Author(s).
语种：
英文
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Na transport in bilayer MoS2and MoS2-WS2heterojunction with S vacancy defect: First-principles study
作者：
Xiao, Jin;Zhou, Juan;Chen, Ling-Na;Chen, Jian
期刊：
AIP Advances ,2022年12(6):065218 ISSN：2158-3226
通讯作者：
Chen, Ling-Na(linda_cjx@163.com)
作者机构：
[Xiao, Jin] Hunan Univ Technol, Sch Sci, Zhuzhou 412007, Peoples R China.;[Zhou, Juan] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.;[Chen, Ling-Na] Univ South China, Comp Sch, Hengyang 421001, Peoples R China.;[Chen, Jian] Changsha Univ Sci & Technol, Coll Energy & Power Engn, Changsha 410076, Peoples R China.
通讯机构：
[Ling-Na Chen] C;Computer School, University of South China , Hengyang 421001, China
摘要：
Based on first-principles calculations, the diffusion properties of Na+ in bilayer MoS2 and the MoS2-WS2 heterojunction were investigated. Owing to the similar structures, the diffusion properties of Na are almost identical in both systems. On perfect surfaces, the diffusion energy barrier is smaller than 0.1 eV. The diffusion characteristics of Na+ ions between layers are related to the size of the system. For a small size (<3 nm(2)), the Na+ diffusion energy barrier is around 0.40 eV because of sliding between layers. With the size of the system increasing, the energy barrier for Na+ diffusion between layers increases to 0.90 eV. S vacancy defects can trap Na+ ions and hinder Na+ diffusion. The diffusion energy barrier on the surface with S vacancy defects will increase to around 0.5 eV. When Na ions are transported between layers, they are tightly bound by S vacancy defects. The energy barrier exceeds 2.0 eV. (C) 2022 Author(s).
语种：
英文
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Critical endwall blockage attenuation-based automatic optimization of casing treatment design for transonic axial flow compressor
作者：
Wang, Xuesong;Benini, Ernesto;Sun, Jinju;Song, Peng;He, Youwei
期刊：
Aerospace Science and Technology ,2022年126:107592 ISSN：1270-9638
通讯作者：
Sun, Jinju(jjsun@mail.xjtu.edu.cn)
作者机构：
[Sun, Jinju; Wang, Xuesong; Song, Peng] Xi An Jiao Tong Univ, Sch Energy & Power Engn, 28 West Xianning Rd, Xi'an 710049, Peoples R China.;[Benini, Ernesto] Univ Padua, Dept Ind Engn, Via Venezia 1, I-35131 Padua, Italy.;[He, Youwei] Univ South China, Coll Mech Engn, 28 West Changsheng Rd, Hengyang 421001, Peoples R China.
通讯机构：
[Jinju Sun] S;School of Energy and Power Engineering, Xi'an Jiaotong University, 28 West Xianning Road, Xi'an, 710049, China
关键词：
Casing treatment;Efficiency;Endwall blockage;Multi-objective optimization;Stall margin;Transonic axial flow compressor
摘要：
Tip leakage flow (TLF) and endwall blockage formation are closely associated with the inception of rotating stall in tip-critical transonic axial flow compressor (AFC) rotors. The present study proposes a critical endwall blockage attenuation-based optimization method of casing treatment design for transonic AFC. First, a well-defined endwall blockage quantification method is developed to reveal the development of the endwall blockage at near-stall, and two blockages of the maximum endwall blockage and the near trailing edge endwall blockage are identified as the critical values for stall inception. Next, both adiabatic efficiency at design point and critical endwall blockages at near-stall are used as optimization objectives in an adaptive surrogate-based optimization procedure to deal with the design of nonuniform multiple grooves casing treatment (NMGCT) for the NASA Stage 35, thus avoiding the extremely time-consuming simulations of compressor performance curves. The analysis of the representative optimal designs demonstrates that the NMGCT can act on the tip flow field in a variety of ways, e.g. lowering the maximum endwall blockage can suppress the intensity of the TLF-shock wave interaction, or lowering the near trailing edge endwall blockage is able to control both the trajectory of the TLF closer to the suction surface and the thickness of the suction surface boundary layer. These achievements can help improving the stall margin of the tip-critical transonic AFC. However, in the case of AFC similar to Stage 35, reducing the maximum endwall blockage can achieve greater stall margin improvement and smaller peak efficiency penalty. © 2022 Elsevier Masson SAS
语种：
英文
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Ultra-high power laser for vitrification of borosilicate glass
作者：
Yu, Shiwei;Liu, Lie;Han, Lianghua;Sun, Xiangyang;Sun, Jiapo;...
期刊：
AIP Advances ,2022年12(9):095211 ISSN：2158-3226
通讯作者：
Liu, Lie(Reseek206@163.com)
作者机构：
[Yu, Shiwei; Liu, Lie; Huang, Haoyue] Univ South China, Sch Elect Engn, Hengyang 421000, Peoples R China.;[Liu, Lie; Zhang, Junze; Han, Lianghua; Wu, Qiupei; Sun, Jiapo; Li, Can] Univ South China, Sch Mech Engn, Hengyang 421000, Peoples R China.;[Liu, Lie; Sun, Xiangyang] Univ South China, Sch Nucl Sci & Technol, Hengyang 421000, Peoples R China.
通讯机构：
[Lie Liu] S;School of Electrical Engineering, University of South China , Hengyang 421000, China
摘要：
The glass solidification technology has been studied by many researchers for decades to handle the trouble of high-level liquid waste (HLLW). However, the widely used joule-heated ceramic melter technology also has disadvantages such as complicated processes, easy deposition of heavy metals, and low thermal efficiency. To deal with these problems, we proposed a new glass solidification device based on ultra-high power laser heating to handle HLLW. HLLW was mixed with borosilicate glass, and melting, clarifying, and annealing processes were carried out in a crucible using laser heat. We test the properties of the borosilicate glass solidified body and then analyze it. The results show that the borosilicate glass beads were completely melted and other indicators are in line with the requirements. As a result, the new device that is heated by an ultra-high laser is feasible for vitrification of HLLW and has the potential to overcome the disadvantages of traditional solidification technology. This research is helpful to explore new glass solidification processes. © 2022 Author(s).
语种：
英文
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An interaction integral method coupled with special crack tip elements for evaluation of stress intensity factors
作者：
Xie, Guizhong;Huang, Rongjie;Dong, Yunqiao;Li, Hao;Li, Ke;...
期刊：
Engineering Analysis with Boundary Elements ,2022年140:421-431 ISSN：0955-7997
通讯作者：
Huang, Rongjie(nysyhrj@163.com)
作者机构：
[Xie, Guizhong; Li, Hao; Du, Wenliao; Zhong, Yudong; Huang, Rongjie; Gong, Xiaoyun; Wang, Liangwen] Zhengzhou Univ Light Ind, Coll Mech & Elect Engn, Henan Prov Key Lab Intelligent Mfg Mech, Zhengzhou 450002, Peoples R China.;[Dong, Yunqiao] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Li, Ke] Hangzhou Vocat & Tech Coll, Hangzhou 310000, Peoples R China.
通讯机构：
[Rongjie Huang; Ke Li; Xiaoyun Gong] H;[Yunqiao Dong] S;Hangzhou Vocational & Technical College, Hangzhou, 310000, China<&wdkj&>School of Mechanical Engineering, University of South China, Hengyang, 421001, China<&wdkj&>Henan Provincial Key Laboratory of Intelligent Manufacturing of Mechanical, College of Mechanical and Electrical Engineering, Zhengzhou University of Light Industry, Zhengzhou, 450002, China
关键词：
Boundary element method;Crack tip element;Interaction integral method;Nearly singular integral;Singular integral;Stress intensity factors
摘要：
Accurate computation of stress intensity factors (SIFs) for two-dimensional cracks by an interaction integral method combined with special crack tip elements is presented in this paper. SIFs are of great importance to fracture mechanics analysis. Due to special variation of displacement around the crack tip and the singularity and near singularity of integrals in interaction integral method, the results obtained by which are affected by the radius of the closed loop. Thus, a general method for singular integrals and nearly singular integrals is applied in the paper. With the interaction integral method coupled with the proposed special crack tip element, more stable and accurate values of the SIFs can be obtained. Numerical examples have demonstrated the effectiveness of the proposed method. © 2022
语种：
英文
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Toward Controllable Wet Etching of Monocrystalline Silicon: Roles of Mechanically Driven Defects
作者：
Wu, Lei;Cui, Licong;He, Wang;Guo, Jian;Yu, Bingjun;...
期刊：
ACS Applied Materials & Interfaces ,2022年14(25):29366-29376 ISSN：1944-8244
通讯作者：
Yu, Bingjun(bingjun@swjtu.edu.cn)
作者机构：
[Yu, Bingjun; Cui, Licong; Qian, Linmao; Wu, Lei; He, Wang] Southwest Jiaotong Univ, Tribol Res Inst, State Key Lab Tract Power, Chengdu 610031, Peoples R China.;[Wu, Lei] Korea Adv Inst Sci & Technol KAIST, Dept Mech Engn, Daejeon 34141, South Korea.;[Guo, Jian] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Yu, B.] T;Tribology Research Institute, State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, China
关键词：
wet chemical etching;mechanically driven defects;amorphous silicon;selective etching mechanism;silicon
摘要：
Wet chemical etching is essential not only for processing silicon (Si) wafers but also for forming diverse structures, significantly promoting the development of the semiconductor industry. However, tight control of etched topography at the nanoscale and even atom-scale in a controllable and reproducible fashion can be hardly achieved in either laboratory research or industrial production, seriously hindering further enhancement of high-performance Si-based electronic devices. Herein, the roles of mechanically driven defects in wet etching were systematically investigated toward promoting controllable wet etching of monocrystalline Si. The role of antietching of mechanically driven amorphous Si (a-Si) and the role of promoting etching of distorted Si (including dislocations and stacking faults) were revealed in anisotropic or isotropic etchants. It was also found that the nucleation of nanocrystals in the a-Si area with increasing contact pressure can lead to deactivation of the antietching mask, and the required contact pressure for deactivation in KOH and tetramethyl ammonium hydroxide solutions was much higher than that in HF/HNO3mixtures. The selective etching mechanisms for every defect including a-Si, distorted Si, and nanocrystals were further addressed down to the atom-scale based on the proposed dissolution model. This study provides insights into deeply understanding the role of defects in wet etching and pushes forward the idea of controllable wet chemical etching in the Si-based semiconductor industry. © 2022 American Chemical Society. All rights reserved.
语种：
英文
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An interval sequential linear programming for nonlinear robust optimization problems
作者：
Tang, Jiachang;Fu, Chunming;Mi, Chengji;Liu, Haibo
期刊：
Applied Mathematical Modelling ,2022年107:256-274 ISSN：0307-904X
通讯作者：
Mi, Chengji(michengji_86@126.com)
作者机构：
[Mi, Chengji; Tang, Jiachang] Hunan Univ Technol, Dept Mech Engn, Zhuzhou 412007, Peoples R China.;[Fu, Chunming] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.;[Liu, Haibo] Hunan Univ Sci & Technol, Hunan Prov Key Lab Hlth Maintenance Mech Equipment, Xiangtan 411201, Peoples R China.
通讯机构：
[Chengji Mi] D;Department of Mechanical Engineering, Hunan University of Technology, Zhuzhou City, 412007, PR China
关键词：
Robust optimization;Interval uncertainty;Reliability-based possibility degree of interval (RPDI);Sensitivity analysis;Sequential linear programming
摘要：
In this paper, interval sequential linear programming (ISLP) is proposed to solve nonlinear robust optimization (RO). The main idea of the programming is to transform the uncertain optimization into several possibility-sensitivity analyses and deterministic linear optimization problems that are sequentially solved. At each cycle, a possibility-sensitivity analysis method is proposed to obtain the approximate partial derivatives of the uncertain constraints at the current design point, based on which a deterministic linear optimization model is constructed and the design point is updated by solving the linear optimization. Moreover, an iterative mechanism is created to adaptively update the design space and improve the convergence rate. Finally, two numerical examples and two practical engineering problems are applied to verify the accuracy and efficiency of the proposed method. © 2022
语种：
英文
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Interval assessments of identified parameters for uncertain structures
作者：
Tang, Jiachang;Cao, Lixiong;Mi, Chenji;Fu, Chunming;Liu, Qiming
期刊：
Engineering with Computers ,2022年38(SUPPL 4):2905-2917 ISSN：0177-0667
通讯作者：
Tang, Jiachang(tangjiachang@hnu.edu.cn);Mi, Chenji(michengji_86@126.com)
作者机构：
[Tang, Jiachang; Mi, Chenji] Hunan Univ Technol, Dept Mech Engn, Zhuzhou 412007, Peoples R China.;[Cao, Lixiong] Hunan Univ, Coll Mech & Vehicle Engn, State Key Lab Adv Design & Mfg Vehicle Body, Changsha 410082, Peoples R China.;[Fu, Chunming] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.;[Liu, Qiming] Hebei Univ Technol, Sch Mech Engn, State Key Lab Reliabil & Intelligence Elect Equip, Tianjin 300401, Peoples R China.
通讯机构：
[Jiachang Tang; Chenji Mi] D;Department of Mechanical Engineering, Hunan University of Technology, Zhuzhou, People’s Republic of China<&wdkj&>Department of Mechanical Engineering, Hunan University of Technology, Zhuzhou, People’s Republic of China
关键词：
Uncertain inverse problem;Interval model;Dimension-reduction method;Adaptive strategy
摘要：
This paper investigates a kind of inverse problem for assessing the uncertainties of identified parameters with uncertainties in structural parameters and limited experimental data. The uncertainty is described by the interval model in which only the bounds of uncertain parameters are required. Directly solving this kind of inverse problem involves a double-loop problem where the outer-loop is interval analysis and the inner-loop is deterministic optimization, which requires a large number of calculations. To efficiently evaluate the effect of interval parameters on the identified parameters, a novel method based on the dimension-reduction method and adaptive collocation strategy is proposed. First, the interval inverse problem is transformed into an inverse-propagation problem, and the dimension-reduction interval method is adopted to transform the interval inverse-propagation problem into several one-dimensional interval inverse-propagation problems. Then, an adaptive collocation strategy is proposed to efficiently estimate the lower and upper bounds of identified parameters. Therefore, the double-loop problem can be transformed into several deterministic inverse problems, and the efficiency of solving the uncertain inverse problem is dramatically improved. Two numerical examples and an engineering application are applied to demonstrate the feasibility and efficiency of the proposed method. © 2021, The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.
语种：
英文
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Thermal-induced structural distortion, charge transfer and magnetic changes of Prussian blue analogs K0.4Co1.3[Fe(CN)6]•nH2O
作者：
Chen, Haiwen;Lu, Zeyi;Liu, Min
期刊：
Chemical Physics Letters ,2021年780:138913 ISSN：0009-2614
通讯作者：
Liu, Min(liuhart@126.com)
作者机构：
[Chen, Haiwen; Liu, Min; Lu, Zeyi] Univ South China, Coll Nucl Sci & Technol, Hengyang 421001, Peoples R China.;[Liu, Min] Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Hengyang, Hunan, Peoples R China.
通讯机构：
[Min Liu] C;College of Nuclear Science and Technology, University of South China, Hengyang 421001, China<&wdkj&>Cooperative Innovation Center for Nuclear Fuel Cycle Technology and Equipment, University of South China
关键词：
Charge transfer;Magnetic properties;Prussian blue analogs;Structural distortion;Thermal induction
摘要：
The K0.4Co1.3[Fe(CN)6]center dot nH2O samples were prepared by co-precipitation method. Powder X-ray diffraction showed that only one HT phase existed in the sample prepared at room temperature ([KCoFe]RT). When the preparation temperature rises to 80 degrees C([KCoFe]80 degrees C), the diffraction peak intensity of primary HT phase weakened and another LT phase appeared. The HT and LT phase are both FCC crystal structure with structural parameters of 10.23 angstrom and 9.93 angstrom, respectively. Infrared and Mo center dot ssbauer spectra indicated that part of FeIIILS-CN-CoIIHS were transformed to FeII LS-CN-CoIII LS configuration when preparation temperature rises to 80 degrees C. It indicated that preparation temperature induced charge transfer from CoII to FeIII ions occurred in present sample. Magnetic analysis showed that these cobalt iron cyanides are both ferrimagnetic. The difference of magnetic moments between the two compounds over the entire temperature range is ascribed to the fact that [KCoFe]RT has more paramagnetic central ions than [KCoFe]80 degrees C. The difference between room temperature theoretical and experimental magnetic moments may be attributed to the weak spin-orbit coupling existing for both ions.
语种：
英文
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Cotransport of uranyl carbonate loaded on amorphous colloidal silica and strip-shaped humic acid in saturated porous media: Behavior and mechanism
作者：
Hou, Wei;Lei, Zhiwu;Hu, Eming;Wang, Hongqiang;Wang, Qingliang;...
期刊：
Environmental Pollution ,2021年285:117230 ISSN：0269-7491
通讯作者：
Wang, Qingliang(670566869@qq.com)
作者机构：
[Hou, Wei; Wang, Hongqiang; Wang, Qingliang; Li, Hui; Zhang, Rui; Hu, Eming; Lei, Zhiwu] Univ South China, Sch Resource & Environm & Safety Engn, Hengyang 421001, Peoples R China.;[Hou, Wei; Wang, Qingliang] Univ South China, Cooperat Innovat Ctr Nucl Fuel Cycle Technol & Eq, Hengyang 421001, Peoples R China.;[Wang, Hongqiang] Univ South China, Hengyang Key Lab Soil Pollut Control & Remediat, Hengyang 421001, Peoples R China.;[Wang, Qingliang; Hu, Eming; Lei, Zhiwu] Univ South China, Hunan Key Lab Rare Met Minerals Exploitat & Geol, Hengyang 421001, Peoples R China.
通讯机构：
[Qingliang Wang] S;School of Resource & Environment and Safety Engineering, University of South China, Hengyang, 421001, China<&wdkj&>Cooperative Innovation Center for Nuclear Fuel Cycle Technology and Equipment, University of South China, Hengyang, 421001, China<&wdkj&>Hunan Key Laboratory of Rare Metal Minerals Exploitation and Geological Disposal of Wastes, University of South China, Hengyang, 421001, China
关键词：
Amorphous silica;Cotransport;Humic acid;Radioactive pollution;Uranyl carbonate
摘要：
Uranyl carbonate (UC(VI)) is a stable form of uranyl (U(VI)) that widely coexists with amorphous colloidal silica (ACSi) and humic acid (HA) in carbonate-rich U-contaminated areas. In this context, the cotransport behavior and mechanism of UC(VI) with ACSi (100 mg L−1) and HA colloids in saturated porous media were systematically investigated. It was found that the ACSi and strip-shaped HA have a strong adsorption capacity for UC(VI), and their adsorption distribution coefficient (Kd) is 4–5 orders of magnitude higher than that of quartz sand (QS). In the ternary system, UC(VI) was mainly existing in the colloid-associated form at low UC(VI) concentration (4.2 × 10−6 M). Compared with the individual transport of UC(VI), the presence of ACSi and strip-shaped HA in the binary system promotes the transport of low-concentration UC(VI) (4.2 × 10−6 M) but shows a hindering effect when UC(VI) = 2.1 × 10−5 M. When ionic strength (IS) increased from 0 to 100 mM, the individual transport of UC(VI) and ACSi was weakened owing to the masking effect and the compression of the electrical double layer, respectively; this weakening effect is more pronounced in the binary (UC(VI)–ACSi) system. Notably, the transport of UC(VI) and ACSi in the ternary system is independent of the changes in IS due to the surface charge homogeneity strengthening the electrostatic repulsion between HA and QS. The Derjaguin–Landau–Verwey–Overbeek theory and retention profiles reveal the co-deposition mechanism of ACSi and UC(VI) in the column under different hydrochemical conditions. The nonequilibrium two-site model and the mathematical colloidal model successfully described the breakthrough data of UC(VI) and ACSi, respectively. These results are helpful for evaluating the pollution caused by UC(VI) migration in an environment rich in HA and formulating corresponding effective control strategies. © 2021 Elsevier Ltd
语种：
英文
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Design and preliminary experimental results of 5 MW-NBI arc power supply for HL-2M tokamak
作者：
Yang, Puqiong;Liu, Bo;Zhang, Ying* ;Wei, Huiling;Xuan, Weimin
期刊：
Fusion Engineering and Design ,2021年172:112728 ISSN：0920-3796
通讯作者：
Zhang, Ying
作者机构：
[Liu, Bo; Yang, Puqiong] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Zhang, Ying] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Wei, Huiling; Xuan, Weimin] Southwestern Inst Phys, Chengdu 610041, Peoples R China.
通讯机构：
[Ying Zhang] S;School of Mechanical Engineering, University of South China, Hengyang, 421001, China
关键词：
Arc discharge;Arc power supply;DC/DC converter;Neutral beam injection (NBI)
摘要：
Due to the nonlinear characteristic of the gas-discharge plasma and influenced of the gas pressure, outside magnetic field and state of cathode, the arc discharge process in ion sources for neutral beam injection(NBI) is difficult to be closed-loop controlled stably with the arc power supply (APS). A 5 MW-NBI APS for HL-2M tokamak based on super capacitor energy storage and switching power technology is designed, results are presented in this paper. A structure of multiple composite chopping is used on the DC/DC converter of the APS power circuit, which is composed of ten interleaving buck converters. With the increasing of the operating frequency, the volume and weight of the filter inductor have been greatly reduced. The APS obtains a higher di/dt and a rapid dynamic response, and the stability of the closed-loop control has been significantly increased. The electrical parameters of factory test of the APS: the maximum output specification is 220 kW/1500 A, output ripple current less than 1%, current rise-times in the order of 100 μS, maximum overshoot less than 3%. The preliminary experimental results of arc discharge showed that: the APS has the characteristics of excellent constant current, and fits well in all kinds of arc discharge experimentations including constant voltage control mode, small arc current discharge cleaning, rating current beam extraction etc. © 2021 Elsevier B.V.
语种：
英文
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Effects of surface texturing on nanotribological properties and subsurface damage of monocrystalline GaN subjected to scratching investigated using molecular dynamics simulation
作者：
Guo, Jian;Chen, Jingjing* ;Lin, Yunzhi;Liu, Zemeng;Wang, Yongqiang*
期刊：
Applied Surface Science ,2021年539:148277 ISSN：0169-4332
通讯作者：
Wang, Yongqiang;Chen, Jingjing
作者机构：
[Guo, Jian; Liu, Zemeng; Lin, Yunzhi; Wang, Yongqiang] Univ South China, Sch Mech Engn, Hengyang 421001, Hunan, Peoples R China.;[Chen, Jingjing] Nanjing Univ Aeronaut & Astronaut, Nanjing 210016, Jiangsu, Peoples R China.;[Chen, Jingjing] Ningde Normal Univ, Sch Informat & Elect Engn, Ningde 352100, Fujian, Peoples R China.
通讯机构：
[Wang, Yongqiang] U;[Chen, Jingjing] N;Univ South China, Sch Mech Engn, Hengyang 421001, Hunan, Peoples R China.;Nanjing Univ Aeronaut & Astronaut, Nanjing 210016, Jiangsu, Peoples R China.
关键词：
GaN;MD simulation;Nano-texture;Nanotribological properties;Subsurface damage
摘要：
Surface nanotribological properties and subsurface damage of flat and textured gallium nitride (GaN) substrates during both linear and circular nanoscratching processes are investigated using molecular dynamics simulation. Results show that the surface texture can remarkably reduce not only the surface friction and wear but also the scratching-induced subsurface damage regardless of the tip radius and penetration depth. Tangential force and friction coefficient decreased with an increase in groove width or depth primarily due to the reduced contact area. The effect of texturing on stress distribution can affect the development of dislocation to alleviate the nanoscale material deformation and removal and thereby reduce surface wear and subsurface damage. Increasing tip radius can reduce the friction coefficient and surface wear, but it promotes subsurface damage. By contrast, increasing tip penetration depth can increase the friction, wear, and subsurface damage for flat and textured GaN substrates. Compared with the c-plane, the m-plane GaN substrate exhibits higher friction but lower material wear, and it has a considerably thicker subsurface damage layer due to the difference in their dislocation networks. This work can provide useful insights into the design of GaN-based material with antifriction and wear properties through the surface texturing treatments. © 2020 Elsevier B.V.
语种：
英文
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Sorting and Identification Method of Camellia Seeds Based on Deep Learning
作者：
Zhang, Xiao;Fengwei, Yuan
作者机构：
[Zhang, Xiao; Fengwei, Yuan] University of South China, College of Mechanical Engineering, Hengyang;421001, China;[Zhang, Xiao; Fengwei, Yuan] 421001, China
会议名称：
40th Chinese Control Conference, CCC 2021
会议时间：
July 26, 2021 - July 28, 2021
会议地点：
Shanghai, China
摘要：
The sorting and identification of camellia seeds is a key technical link in the production and processing of camellia oil. The accurate removal of moldy camellia seeds can reduce the acidity of camellia oil, and the removal of camellia husks can improve the quality of subsequent production of camellia oil products. The traditional image processing methods face the problems of poor human selection features and complex feature extraction process. In this paper, a method for sorting and identifying camellia seeds based on deep learning is established. Based on the Resnet-18 network model, a transfer learning method is used to establish the camellia seed sorting and identification model. This Resnet-18 convolutional neural network proposes a residual function and Shortcut Connections to solve the problem of result degradation and the disappearance of gradient as the number of network layers deepens question. This model can independently recognize the effective features of the object, avoiding the complex process of artificially extracting features in traditional recognition algorithms. In addition, an image acquisition device is designed for the camellia seed mixture after the dehulling process and 1, 200 sample pictures were collected. After testing, when the learning rate is 0.001 and the MiniBatchSize is 16, the recognition accuracy rate is 96.21%. The experimental data show that this method can effectively sort and identify Camellia seeds. This research provides a certain theoretical reference for the design of camellia seed sorting machinery. © 2021 Technical Committee on Control Theory, Chinese Association of Automation.
语种：
英文
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A method of detecting level change of uranium fluorination mixture in the hopper by gamma-ray dose
作者：
Lei, JieHeng;Lei, Lin;Qin, QianQian;Yin, Zeyuan;Lei, ZeYong
期刊：
Applied Radiation and Isotopes ,2021年174:109712 ISSN：0969-8043
通讯作者：
Lei, Lin(xlinw@126.com)
作者机构：
[Lei, JieHeng] Univ South China, Sch Elect Engn, Hengyang 421001, Hunan, Peoples R China.;[Lei, Lin] Univ South China, Sch Resources & Environm & Safety Engn, Hengyang 421001, Hunan, Peoples R China.;[Yin, Zeyuan; Lei, ZeYong; Qin, QianQian] Univ South China, Sch Mech Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Lin Lei] S;School of Resources & Environment and Safety Engineering, University of South China, Hengyang, 421001, Hunan province, China
关键词：
Gamma radiation measurement;Uranium fluoride;Materials level;Algorithms of gamma radiation field
摘要：
The measurement of material level change in uranium fluorination has an essential influence on uranium production quality. In this study, a method to determine the level change of uranium fluorination mixture in the hopper by online radiation meter outside hopper is established. We have designed an experiment to study the change of radiation field outside the hopper with a known height of radioactive material to discover its regular pattern. The experimental results show that when the probe is placed 50 mm away from the cylinder wall, the average radiation dose is more significant, and the change of radiation dose measured by the instrument at this position is more evident than that at other positions. Then through the measurement of the external radiation field of the hopper with unknown material level to estimate the material level, and by opening the cover of hopper to verify the accuracy of the material level measurement method. Based on the experimental results and theoretical analysis, a method and formula for judging the mixture material are proposed. This method can quickly determine the level of uranium fluoride mixture in the hopper online, realize the accurate control of material parameters in the process of uranium conversion, and improve the quality of uranium conversion products.
语种：
英文
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Near singularity cancellation in weakly singular integrals of three-dimensional boundary element method
作者：
Xie, Guizhong;Zhong, Yudong* ;Li, Hao;Du, Wenliao* ;Feng, Shizhe* ;...
期刊：
Engineering Analysis with Boundary Elements ,2020年118:54-59 ISSN：0955-7997
通讯作者：
Zhong, Yudong;Du, Wenliao;Feng, Shizhe
作者机构：
[He, Wenbin; Xie, Guizhong; Li, Hao; Du, Wenliao; Zhong, Yudong; Cheng, Jiahui; Wang, Liangwen; Zhong, YD] Zhengzhou Univ Light Ind, Mech & Elect Engn Inst, Henan Prov Key Lab Intelligent Mfg Mech, Zhengzhou 450002, Henan, Peoples R China.;[Feng, Shizhe] Hebei Univ Technol, Sch Mech Engn, Tianjin 300130, Peoples R China.;[Dong, Yunqiao] Univ South China, Sch Mech Engn, Hengyang 421001, Hunan, Peoples R China.
通讯机构：
[Zhong, YD; Du, WL] Z;[Feng, Shizhe] H;Zhengzhou Univ Light Ind, Mech & Elect Engn Inst, Henan Prov Key Lab Intelligent Mfg Mech, Zhengzhou 450002, Henan, Peoples R China.;Hebei Univ Technol, Sch Mech Engn, Tianjin 300130, Peoples R China.
关键词：
Singular integrals;Sinh transformation;Duffy transformation;Boundary element method
摘要：
This paper focuses on near singularity in weakly singular integrals of three-dimensional boundary element method. In traditional methods, only one directional transformation is introduced to remove the weak singularity. However, near singularity is still existed. Thus in our paper, serval methods for removal of weak singularity are introduced firstly. Then, angular and sigmoidal transformations are introduced to remove the near singularity in the circumferential direction combined with polar transformation. Generalized Duffy transformation is introduced to remove weak singularity in u direction, which also separates the near singularity in v direction. Based on this method, sinh transformation is constructed with the integrand of v. Finally, several numerical examples considering large top opening angle of the singular integration element and large ratio of the two edge length of the angle (the max edge length/ the min edge length) are proposed. Results demonstrate that generalized Duffy transformation coupled with sinh transformation in v direction is a best choose for weakly singular integrals. © 2020
语种：
英文
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Investigation on the influence of heat on the dynamic characteristics of a gear transmission system
作者：
Luo, Biao;Li, Wei*
期刊：
Engineering Failure Analysis ,2020年116:104724 ISSN：1350-6307
通讯作者：
Li, Wei
作者机构：
[Luo, Biao] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.;[Li, Wei; Luo, Biao] Univ Sci & Technol Beijing, Sch Mech Engn, Beijing 100083, Peoples R China.
通讯机构：
[Li, Wei] U;Univ Sci & Technol Beijing, Sch Mech Engn, Beijing 100083, Peoples R China.
关键词：
Dynamic characteristics;Equivalent viscous damping;Gear transmission system;Heat;Time-varying meshing stiffness
摘要：
In order to study the influence of heat on dynamic characteristics of gear transmission system, the meshing thermal stiffness of gear was proposed, and it was introduced into the system dynamics equation. Meanwhile, the equivalent viscous damping of the system was studied by using the Coulomb friction damping model. Thus, the thermal dynamics model of system was established. In this article, the thermal dynamics model of gear system was established and solved. The comparative analysis of the thermal dynamic response and elastic dynamic response of the system was also provided. The results show that the maximum peak value, vibration velocity, and equilibrium position of thermal dynamic response are all bigger than those of the elastic dynamic response. The maximum dynamic load is found at the alternating point of double teeth region to single tooth region, and the maximum thermal dynamic load and thermal dynamic load coefficient are smaller than those of the elastic system because of the increases of the equivalent viscous damping. Additionally, the theoretical model is verified by finite element method and experimental method, respectively. © 2020 Elsevier Ltd
语种：
英文
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二维圆周平动法ADP单晶生长流动与传质数值模拟
作者：
刘杭;李明伟;王鹏飞;胡志涛;尹华伟
期刊：
材料导报 ,2020年34(20):20022-20027 ISSN：1005-023X
作者机构：
[刘杭; 李明伟; 王鹏飞] Key Laboratory of Low-grade Energy Utilization Technologies and Systems, School of Energy and Power Engineering, Chongqing University, Chongqing;400030, China;[胡志涛] School of Mechanical Engineering, University of South China, Hengyang;421001, China;[尹华伟] School of Environmental and Chemical Engineering, Chongqing Three Gorges University, Chongqing
关键词：
流动传质;ADP单晶;二维圆周平动法;溶液法晶体生长;数值模拟
摘要：
本工作提出一种名为"二维圆周平动法"的新型晶体生长方法。采用有限容积法和动网格技术,对转晶法及二维圆周平动法的ADP单晶生长过程进行数值模拟。比较了两种生长方法下晶体表面时均过饱和度分布及均方差,分析了不同特征转速ω、不同圆周轨道半径R、不同晶体尺寸A对晶面时均过饱和度及均方差的影响。结果表明:与转晶法相比,二维圆周平动法晶面过饱和度及其分布均匀性得到提高。随着特征转速ω或圆周轨道半径R的增加,晶面时均过饱和度增加,均匀性变好,有利于晶面形貌的稳定。然而,随着尺寸A的增大,晶面时均过饱和度值降低,其均匀性变差。因而,随着晶体的长大,应该适当增加特征转速ω或圆周轨道半径R。
语种：
中文
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Research on preparation of particles by crushing the waste glass which contains lead and the addition technique in concrete
作者：
Shen Long-Zhang* ;Qiu Chang-Jun;Wu Xiao-Yan;Ke Guo-Jun
期刊：
Ferroelectrics ,2019年548(1):72-81 ISSN：0015-0193
通讯作者：
Shen Long-Zhang
作者机构：
[Qiu Chang-Jun; Shen Long-Zhang; Wu Xiao-Yan] Univ South China, Sch Mech Engn, Hengyang, Hunan, Peoples R China.;[Ke Guo-Jun; Wu Xiao-Yan] Univ South China, Hunan Prov Engn Res Ctr Radioact Control Technol, Hengyang, Hunan, Peoples R China.;[Ke Guo-Jun; Wu Xiao-Yan] Univ South China, Hunan Prov Engn Technol Res Ctr Uranium Tailings, Hengyang, Hunan, Peoples R China.
通讯机构：
[Shen Long-Zhang] U;Univ South China, Sch Mech Engn, Hengyang, Hunan, Peoples R China.
关键词：
Concrete aggregates;glass crusher;shielding performance
摘要：
Untreated leaded waste glasses will pollute the environment which can release lead ions. Which is can be solidified into the concrete after being broken. Then the pollution problems could be solved, and the concrete slabs would radiation protection specialty of be increased. In this paper, the entire process of the crushing of waste glass which contains lead and its addition technique in concrete could be designed and researched after the FEM and EDEM analysis. A new double toothed roll crusher was studied base on the traditional crashers in this paper, and its work mechanism, structure and technique characteristics were introduced to crash the glass into the specified size. The morphological structure and optical transparence of the particles could be watched through a wide depth of field microscope. © 2019, © 2019 Taylor & Francis Group, LLC.
语种：
英文
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Specific Self-Repairing by Morphology Prejudging
作者：
Wang, Pengfei;Li, Mingwei* ;Hu, Zhitao;Hu, Zhiqiang;Hu, Jinsan
期刊：
Crystal Research and Technology ,2019年54(12):1900149- ISSN：0232-1300
通讯作者：
Li, Mingwei
作者机构：
[Hu, Zhitao; Hu, Jinsan; Li, Mingwei; Wang, Pengfei] Chongqing Univ, Sch Energy & Power Engn, Minist Educ, Key Lab LowGrade Energy Utilizat Technol & Syst, Chongqing 400030, Peoples R China.;[Hu, Zhiqiang] Univ South China, Sch Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Li, Mingwei] C;Chongqing Univ, Sch Energy & Power Engn, Minist Educ, Key Lab LowGrade Energy Utilizat Technol & Syst, Chongqing 400030, Peoples R China.
关键词：
convex polyhedron of minimum volume;incomplete KDP crystal;morphology prejudging;thin surface layer regeneration
摘要：
The thin surface layer growth during the regeneration of incomplete potassium dihydrogen phosphate crystal is more perplexing than the ordinary layer-by-layer growth. In a previous paper, the driving force of the thin surface layer growth was discussed; the present paper focuses on the regeneration process and final regeneration morphology. Based on the analysis of thin surface layer area per unit repaired volume, it is found that convex polyhedron is more advantageous than concave polyhedron. It is also found that the general morphology of repaired incomplete crystal is convex polyhedron of minimum volume covered by singular surfaces. The most important thing is, numbers of regeneration details suggest that the incomplete crystal achieves the self-repairing by morphology prejudging. © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
语种：
英文
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Interval differential evolution with dimension-reduction interval analysis method for uncertain optimization problems
作者：
Fu, Chunming* ;Liu, Yongxia;Xiao, Zhang
期刊：
Applied Mathematical Modelling ,2019年69:441-452 ISSN：0307-904X
通讯作者：
Fu, Chunming
作者机构：
[Liu, Yongxia; Fu, Chunming; Xiao, Zhang] Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
通讯机构：
[Fu, Chunming] U;Univ South China, Coll Mech Engn, Hengyang 421001, Peoples R China.
关键词：
Nonlinear interval optimization;Uncertainty;Differential evolution;Interval analysis;Interval arithmetic
摘要：
A constrained nonlinear interval optimization method under the framework of differential evolution algorithm is developed to solve the uncertain structural optimization problems with interval uncertainties. The proposed method is a direct optimization method based on the interval differential evolution and dimension-reduction interval analysis. The interval preferential rule based on the satisfaction value of interval possibility degree model is used to realize the direct interval ranking of different design vectors. At each evolutionary generation, the outer optimizer by differential evolution optimizer searches for the best solution within the design space. The dimension-reduction interval analysis is employed to calculate the intervals of objective and constraints for each design vector in the inner layer. This operation transforms the original nesting optimization problem into a single loop one which improves the computational efficiency of the proposed method. Finally, the effectiveness of the presented direct method is verified by two numerical examples and an engineering application. © 2018 Elsevier Inc.
语种：
英文
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