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SIMPLE SHAKEDOWN OF STRUCTURES UNDER VARIABLE MULTI-LOADINGS

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Acta Mechanica Solida Sinica 2008年第2期21卷 141-148页

作者： Yuall Yuall yingqiang xu Guozhi Lu School of Aeronautics Northwestern Polytechnical University Xian 710072 China

The shakedown analysis of structures under variable multi-loadings is considered, and the corresponding simple shakedown condition is presented in this paper. Distribution of fixed stresses field is given, and the self-equilibrium of fixed stresses field is analyzed. Elastic shakedown and plastic shakedown conditions are presented based on the fixed stresses field. The theorem is convenient to evaluate the shakedown limit of structures under cyclical variable multiloadings through solving positive scalar fields and fixed stresses field factors at a series of dangerous positions of the structure, and tedious computations are avoided. Finally the theorem is applied to a thick-walled cylindrical tube under variable pressure and temperature, and the rolling contact problem. The results are in good agreement with some computational results.

关键词： shakedown limit residual stress field variable multi-loadings

Comparison of short period InAs/GaSb superlattices on GaSb and GaAs substrates

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Science China(Technological Sciences) 2009年第1期52卷 23-27页

作者： GUO Jie CHEN HuiJuan SUN WeiGuo HAO RuiTing xu yingqiang NIU ZhiChuan Material School NorthWest Polytechnical UniversityXi’an 610000China Luoyang Optical Electronics Center Luoyang 471009China Institute of Semiconductors Chinese Academy of SciencesBeijing 100083China

Type II superlattices (SLs) short period InAs(4ML)/GaSb(8ML) were grown by molecular-beam epitaxy on lattice-mismatched GaAs substrates and on GaSb substrates. A smooth GaSb epilayer was formed on GaAs substrates by inserting mulit-buffer layers including an interfacial misfit mode AlSb quantum dot layer and AlSb/GaSb superlattices smooth layer. SLs grown on GaAs substrates (GaAs-based SLs) showed well-resolved satellite peaks in XRD. GaSb-based SLs with better structural quality and smoother surface showed strong photoluminescence at 2.55 μm with a full width at half maximum (FWHM) of 20 meV, narrower than 31 meV of GaAs-based SLs. Inferior optical absorption of GaAs-based SL was observed in the range of 2―3 μm. Photoresponse of GaSb-based SLs showed the cut-off wavelength at 2.6 μm.

关键词： InAs/GaSb superlattice substrates infrared detector

Dual strategy of modulating growth temperature and inserting ultrathin barrier to enhance the wave function overlap in type-Ⅱ superlattices

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Nano Research 2022年第6期15卷 5626-5632页

作者： Yuyang Wu Yahui Zhang Yi Zhang Yunhao Zhao Yu Zhang yingqiang xu Chongyun Liang Zhichuan Niu Yi Shi Renchao Che Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative MaterialsDepartment of Materials ScienceFudan UniversityShanghai 200438China State Key Laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China National Laboratory of Solid-State Microstructures School of Electronic Science and Engineering and CollaborativeInnovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China Joint-Research Center for Computational Materials Zhejiang LaboratoryHangzhou 311100China

Maximizing wave function overlap(WFO)within type-II superlattices(T2SL)is demonstrated to be important for improving their photoelectric properties,such as optical transition strength and quantum efficiency,which,however,remains a great challenge for ***,the dual strategy of modulating growth temperature and inserting ultrathin AlAs barrier into the AlSb layers is presented to enhance the WFO in InAs/AlSb *** charge distributions and strain states indicate that moderate growth temperature of 470°C promotes the As-Sb exchange at AlSb-on-InAs(AOI)interfaces,which would introduce skew of energy band structure towards InAs-on-AlSb(IOA)*** band structure could drive electrons and holes to the IOA interfaces simultaneously,thus resulting in the enhanced *** this basis,insertion of relatively thick(0.3 nm)AlAs layers is found to squeeze more holes towards adjacent interfaces,boosting the WFO *** InAs/AlSb superlattices with optimized WFO reveal better optical performance,where the peak intensity shows 50%improvement in the PL spectra than the original ***,a dual-miniband radiative transition mechanism appears in the InAs/AlSb superlattice with relatively thick AlAs intercalation,which helps broaden the wavelength range of the superlattice.

关键词： wave function overlap type-II superlattices photoelectric properties charge distribution energy band alignment

High order DBR GaSb based single longitude mode diode lasers at 2 μm wavelength

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Journal of Semiconductors 2018年第10期39卷 58-63页

作者： Hao Luo Cheng'ao Yang Shengwen Xie Xiaoli Chai Shushan Huang Yu Zhang yingqiang xu Zhichuan Niu State Key Laboratory of Superlattices and Microstructures Institute of SemiconductorsChinese Academy of Sciences College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China

The GaSb-based distributed Bragg reflection（DBR） diode laser with 23 rd-order gratings have been fabricated by conventional UV lithography and inductively coupled plasma（ICP） etching. The ICP etching conditions were optimized and the relationship among etching depth, duty ratio and side-mode suppression ratio（SMSR） was studied. The device with a ridge width of 100 μm, gratings period of 13 μm and etching depth of 1.55 μm as well as the duty ratio of 85% was fabricated, its maximum SMSR reached 22.52 dB with uncoated cavity facets under single longitudinal operation mode at room temperature.

关键词： GaSb-based distributed Bragg reflection inductively coupled plasma single longitudinal mode highorder gratings

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飞机前缘蒙皮数字化精确拉形技术

南京航空航天大学学报 2012年第B04期44卷 79-82页

作者：刘垒徐应强上海飞机制造有限公司钣金制造车间上海200436

总结分析飞机前缘蒙皮的成形工艺特点。选取典型零件,设计加载轨迹方案及参数,利用有限元分析进行工艺参数优化,分析主要工艺参数对成形的影响规律。根据有限元优化结果,利用ASSFCAE FET600软件生成数控代码,进行生产性实验和测量分析,... 详细信息

总结分析飞机前缘蒙皮的成形工艺特点。选取典型零件,设计加载轨迹方案及参数,利用有限元分析进行工艺参数优化,分析主要工艺参数对成形的影响规律。根据有限元优化结果,利用ASSFCAE FET600软件生成数控代码,进行生产性实验和测量分析,获得了合格的零件,实现飞机前缘蒙皮精确拉伸成形。

关键词：钣金成形拉伸成形前缘蒙皮数控

Boosting reversible charging of Li-ion batteries at low temperatures by a synergy of propylene carbonate-based electrolyte and defective graphite

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Nano Research 2024年第3期17卷 1491-1499页

作者： yingqiang Wu Jiao Zhang Jinli Liu Li Sheng Bo Zhang Limin Wang Siqi Shi Li Wang Hong xu Xiangming He Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of Sciences(CAS)Changchun 130022China China National Quality Supervision and Inspection Center for Industrial Explosive Materials Nanjing University of Science and TechnologyNanjing 210094China School of Materials Science and Engineering Materials Genome InstituteShanghai UniversityShanghai 200444China

Propylene carbonate(PC)-based electrolytes have exhibited significant advantages in boosting the low-temperature discharging of graphite-based Li-ion ***,it is still unclear whether they can improve the charging property and suppress lithium *** this topic is challenging due to the problem of electrochemical *** overcome this issue,we introduced graphite with phase *** results show that the pouch-type full batteries using PC-based electrolyte exhibit steady performance over 500 cycles and can be reversibly charged over 30 times at-20℃ with an average Coulombic efficiency of 99.95%,while the corresponding value for the conventional ethylene carbonate(EC)-based electrolyte sample is only 31.20%.This indicates that the use of PC-based electrolyte significantly suppresses lithium plating during low-temperature *** further demonstrate that the improved performance is mainly attributed to the unique solvation structure,where PF-6more anions participate in solvation,leading to the formation of a stable F-rich solid state electrolyte interface on the graphite surface and a lower reduction tendency of Li+*** work inspires new ideas for the design of PC-based electrolytes for low-temperature charging and fast-charging batteries.

关键词： lithium-ion batteries graphite propylene carbonate low-temperature charging

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液氮生态系统与中国现代能源体系构建

学术前沿 2022年第13期 66-75页

作者：徐应强中国科学院半导体研究所

碳达峰、碳中和“30·60目标”成为我国新时期高质量发展的关键目标,事关今后几十年的经济增长模式和产业结构、能源结构调整,对消费模式、生活方式及生态建设有深刻影响。液氮作为一种新能源介质,不仅可以用于发电、汽车发动机、数据... 详细信息

碳达峰、碳中和“30·60目标”成为我国新时期高质量发展的关键目标,事关今后几十年的经济增长模式和产业结构、能源结构调整,对消费模式、生活方式及生态建设有深刻影响。液氮作为一种新能源介质,不仅可以用于发电、汽车发动机、数据中心散热、化石燃料降碳、超导输电,而且也可广泛应用于国防军工、科学研究、临床医学等领域,从而形成一个节能—储能—产能—输能的碳达峰一体化生态。这样一个液氮生态系统,在实现不受限地理条件储能的同时,带动了我国其他领域,诸如红外焦平面、低温电路、超算芯片、半导体大型生产设备、医疗技术、新能源汽车、量子计算等的发展,拓展了盈利模式,建立了多元收益方式,实现了储能产业规模化发展,为构建我国液氮新能源体系提供了一种全新的思路,对全面构建我国现代能源体系有着重要意义。

关键词：碳达峰储能液氮生态系统能源体系

考虑风电不确定性的互联电力系统分散协调调度模型

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电力系统自动化 2018年第16期42卷 41-47,160页

作者：任建文许英强新能源电力系统国家重点实验室(华北电力大学) 河北省保定市071003

针对含高比例风电的直流互联电力系统经济调度问题,采用鲁棒优化方法描述风电出力,提出了一种基于目标级联分析法的分散协调调度模型。首先,采用鲁棒优化方法中的多面体集合来描述风电出力的不确定性,为了降低问题求解的保守度,引入了... 详细信息

针对含高比例风电的直流互联电力系统经济调度问题,采用鲁棒优化方法描述风电出力,提出了一种基于目标级联分析法的分散协调调度模型。首先,采用鲁棒优化方法中的多面体集合来描述风电出力的不确定性,为了降低问题求解的保守度,引入了鲁棒保守度调节因子。然后,根据分散协调算法的分解原理将待解决的经济调度问题分解为主问题和子问题。其中,主问题为上级调度中心协调优化互联电力系统之间的直流联络线功率,子问题为下级调度中心独立优化各区域电网的发电计划。最后,通过两个算例对所提模型的有效性进行了验证。结果表明,所提方法不仅可以弥补鲁棒优化方法偏于保守的不足,而且能够在应对风电出力不确定性的同时实现风电的跨区域消纳,适合中国电网目前的分层分区调度模式。

关键词：风电消纳互联电力系统分散协调调度鲁棒优化目标级联分析

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粗糙球形表面的分形接触力学模型

西安交通大学学报 2019年第5期53卷 176-186页

作者：原园张利华徐颖强西安理工大学机械与精密仪器工程学院西安710048 西北工业大学机电学院西安710072

为了获得粗糙表面点接触的力学特性,提高接触元件的承载能力,采用Weierstrass-Mandelbrot函数生成了三维粗糙球形表面,建立了粗糙球形表面与一刚性平面接触的分形力学模型,推导出不同接触区域上各个频率指数的微凸体的截断面积密度分布... 详细信息

为了获得粗糙表面点接触的力学特性,提高接触元件的承载能力,采用Weierstrass-Mandelbrot函数生成了三维粗糙球形表面,建立了粗糙球形表面与一刚性平面接触的分形力学模型,推导出不同接触区域上各个频率指数的微凸体的截断面积密度分布函数,获得了真实接触面积与总接触载荷的解析表达式,得到了接触半宽上的接触压力分布。计算结果表明:微凸体的频率指数范围直接影响粗糙球形表面的接触力学性质;当最小频率指数n_(min)与临界弹性频率指数n_(ec)满足n_(min)+5≤n_(ec)时,粗糙球形表面在整个接触过程中呈现弹性变形性质,当最小频率指数n_(min)与临界弹塑性频率指数n_(epc)满足n_(min)>n_(epc)时,粗糙球形表面在整个接触过程中呈现非弹性变形性质;粗糙球形表面的接触半宽主要由基圆确定,对于相同比例的下压量,接触压力峰值与最小频率指数成正比;在弹性变形与弹塑性变形阶段,接触压力在接触区域中心达到最大,向接触区域边缘方向递减,在完全塑性变形阶段,接触压力在整个接触区域近似均匀分布。

关键词：粗糙球形表面分形微凸体接触频率指数