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Arc erosion behavior of a nanocomposite W-Cu electrical contact material

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Rare Metals 2006年第1期25卷 37-42页

作者： CHEN Wenge KANG Zhanying SHEN Hongfang DING Bingjun School of Materials Science and Engineering Xi＇an University of Technology Xi＇an 710048 China department of Materials physics Xi＇an Jiaotong University Xi＇an 710049 China

The erosion behavior of a nanocomposite W-Cu material under arc breakdown was investigated. The arc erosion rates of the material were determined, and the eroded surfaces and arc erosion mechanisms were studied by scanning eleclion microscopy. It is concluded that the nanocomposite W-Cu electrical contact material shows a characteristic of spreading arcs. The arc breakdown of a commercially used W-Cu alloy was limited in a few areas, and its average arc erosion rate is twice as large as that of the former. Furthermore, it is also proved that the arc extinction ability and arc stability of the nanocomposite W-Cu material are excellent, and melting is the major failure modality in the make-and-break operation of arcs.

关键词： arc erosion W-Cu alloy contact materials nanocomposite

Sensitivity to Estimation Errors in Mean-variance Models

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Acta Mathematicae Applicatae Sinica 2003年第2期19卷 255-266页

作者： Zhi-ping Chen, Cai-e Zhaodepartment of Scientific Computing and applied Softwares, Faculty of Science, xi’an {3. University,{3., China department of Scientific Computing and applied Softwares Faculty of Science Xi'an Jiaotong University Xi'an China

Abstract In order to give a complex and accurate description about the sensitivity of efficient portfolios to changes in asset's expected returns, variances and covariances, the joint effect of estimation errors in means, variances and covariances on the efficient portfolio's weights is investigated in this paper. It is proved that the efficient portfolio's composition is a Lipschitz continuous, differentiable mapping of these parameters under suitable conditions. The change rate of the efficient portfolio's weights with respect to variations about risk-return estimations is derived by estimating the Lipschitz constant. Our general quantitative results show that the efficient portfolio's weights are normally not so sensitive to estimation errors about means and variances. Moreover, we point out those extreme cases which might cause stability problems and how to avoid them in practice. Preliminary numerical results are also provided as an illustration to our theoretical results.

关键词： Keywords The MV model estimation error sensitivity Lipschitz continuity

GLOBAL SOLUTIONS AND BLOW UP FOR ACTIVATOR INHIBITOR MODEL

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Systems Science and Mathematical Sciences 1998年第3期11卷 238-244页

作者： ZHANG Quande(department of Mathematics, Shaanxi Normal University, xi’an 710062, China)LI Kaitai(Research Center for {3. Mathematics, xi’an jiaotong University,{3., China)

This paper deals with the existence and nonexistence of global positive solutions of initial and boundary value problem for the general activator-inhibitor model In this paper, we do not restrict ourselves to the initial data 1/uo, 1/uo ∈L∞(Ω). We prove that there exist glolal solutions if 0 ≤ u0 ≤ u0 and they will blow up in finite time if 0 ≤ v0 ＜ u0 whether u0, v0 are small or large.

关键词： Global solutions blow up of solution activator-inhibitor model

腔损对单原子微激射器中产生稳定四阶与振幅平方压缩态的影响

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物理学报 1996年第4期45卷 563-572页

作者：李福利西安交通大学应用物理系西安710049

研究了利用相干陷落方法在单原子微激射器中产生具有四阶压缩和振幅平方压缩性质的稳态腔场.结果表明,在目前微激射器实验的腔损条件下,如果注入腔中的原子初始处于相干态,只要原子束的通量适当大,当原子在腔中的飞行时间满足陷落条件时... 详细信息

研究了利用相干陷落方法在单原子微激射器中产生具有四阶压缩和振幅平方压缩性质的稳态腔场.结果表明,在目前微激射器实验的腔损条件下,如果注入腔中的原子初始处于相干态,只要原子束的通量适当大,当原子在腔中的飞行时间满足陷落条件时,腔场可进入相干陷落态。

关键词：单原子微激射器腔损原子量子光学

Phase separation and rapid solidification of liquid Cu_(60)Fe_(3.)Co_(10) ternary peritectic alloy

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Science China(physics,Mechanics & Astronomy) 2007年第4期50卷 509-518页

作者： DAI FuPing, CAO ChongDe & WEI BingBo department of applied physics, Northwestern Polytechnical University, {3.’an 710072, China 1. department of applied physics Northwestern Polytechnical University Xi’an 710072 China

The metastable liquid phase separation and rapid solidification of Cu60Fe3.Co10 ternary peritectic alloy were investigated by using the drop tube technique and the differential scanning calorimetry method. It was found that the critical temperature of metastable liquid phase separation in this alloy is 1623.5 K, and the two sepa- rated liquid phases solidify as Cu(Fe,Co) and Fe(Cu,Co) solid solutions, respec- tively. The undercooling and cooling rate of droplets processed in the drop tube increase with the decrease of their diameters. During the drop tube processing, the structural morphologies of undercooled droplets are strongly dependent on the cooling rate. With the increase of the cooling rate, Fe(Cu,Co) spheres are refined greatly and become uniformly dispersed in the Cu-rich matrix. The calculations of Marangoni migration velocity (VM) and Stokes motion velocity (VS) of Fe(Cu,Co) droplets indicated that Marangoni migration contributes more to the coarsening and congregation of the minor phase during free fall. At the same undercooling, the VM/VS ratio increases drastically as Fe(Cu,Co) droplet size decreases. On the other hand, a larger undercooling tends to increase the VM/VS value for Fe(Cu,Co) drop- lets with the same size.

关键词： ternary peritectic alloy metastable immiscibility rapid solidification reduced gravity liquid phase separation

Digital image processing of sectorial oscillations for acoustically levitated drops and surface tension measurement

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Science China(physics,Mechanics & Astronomy) 2010年第12期53卷 2260-2265页

作者： SHEN ChangLe, xiE WenJun & WEI BingBo department of applied {3., Northwestern Polytechnical University, xi’an 710072, China 1. department of applied physics Northwestern Polytechnical University Xi’an 710072 China

A type of non-axisymmetric oscillations of acoustically levitated drops is excited by modulating the ultrasound field at proper frequencies. These oscillations are recorded by a high speed camera and analyzed with a digital image processing method. They are demonstrated to be the third mode sectorial oscillations, and their frequencies are found to decrease with the increase of equatorial radius of the drops, which can be described by a modified Rayleigh equation. These oscillations decay exponentially after the cessation of ultrasound field modulation. The decaying rates agree reasonably with Lamb’s prediction. The rotating rate of the drops accompanying the shape oscillations is found to be less than 1.5 rounds per second. The surface tension of aqueous ethanol has been measured according to the modified Rayleigh equation. The results agree well with previous reports, which demonstrates the possible application of this kind of sectorial oscillations in noncontact measurement of liquid surface tension.

关键词： acoustic levitation drop oscillation image processing surface tension

Simulation study of multi-layer titanium nitride nanodisk broadband solar absorber and thermal emitter

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Communications in Theoretical physics 2024年第11期 153-162页

作者： xi Huang Yingting Yi Qianju Song Zao Yi Can Ma Chaojun Tang Qingdong Zeng Shubo Cheng Rizwan Raza School of Mathematics and Science Joint Laboratory for Extreme Conditions Matter Properties The State Key Laboratory of Environment-friendly Energy Materials Tianfu Institute of Research and InnovationSouthwest University of Science and Technology College of physics Central South University department of Oncology Sichuan Science City Hospital School of Chemistry and Chemical Engineering Jishou University College of Science Zhejiang University of Technology School of physics and Electronic-information Engineering Hubei Engineering University School of physics and Optoelectronic Engineering Yangtze University department of physics COMSATS Institute of Information Technology

Solar energy has always been a kind of energy with large reserves and wide application. It is well utilized through solar absorbers. In our study, the finite difference time domain method(FDTD)is used to simulate the absorber composed of refractory metal materials, and its absorption performance and thermal emission performance are obtained. The ultra-wide band of 200 nm–3.00 nm reaches 95.93. absorption efficiency, of which the bandwidth absorption efficiency of253. nm(200 nm–273. nm) is greater than 90%. The absorption efficiency in the whole spectrum range(200 nm–273. nm) is 97.17% on average. The multilayer nanodisk structure of the absorber allows it to undergo strong surface plasmon resonance and near-field coupling when irradiated by incident light. The thermal emission performance of the absorber enables it to also be applied to the thermal emitter. The thermal emission efficiency of 95.3.% can be achieved at a high temperature of up to 1500 K. Moreover, the changes of polarization and incident angle do not cause significant changes in absorption. Under the gradual change of polarization angle(0°–90°), the absorption spectrum maintains a high degree of consistency. As the incident angle increases from 0° to 60°, there is still 85% absorption efficiency. The high absorption efficiency and excellent thermal radiation intensity of ultra-wideband enable it to be deeply used in energy absorption and conversion applications.

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Optimal Management of Two-Species Bioeconomics Systems

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生物数学学报 1998年第1期13卷 9-14页

作者： Shou Jilin Tarafdar E U Li Yanmei(department of applied Mathematics,xi'an {3. University,xi'an {3.,P.R.China)(department of Mathematics,The University of Queensland,Australia) 西安交通大学应用数学系陕西西安 The University of Queensland 澳大利亚

In this paper,the Optimal Control Theory is applied to two-species bioeconomic *** optimal harvest policies are presented when one fleet makes natural mixed harvest and when one fleet is divided into two groups to harvest two independent species or two competitive species,*** connections and differences between them are also considered.

关键词： Renewable resource two-species bioeconomics system optimal management

Non-destructive buffer enabling near-infrared-transparent inverted inorganic perovskite solar cells toward 14.0 h light-soaking stable perovskite/Cu(In,Ga)Se_(2) tandem solar cells

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Journal of Energy Chemistry 2024年第10期97卷 622-629,I0013页

作者： Yu Zhang Zhaoheng Tang Zhongyang Zhang Jiahong Tang Minghua Li Siyuan Zhu Wenyan Tan xi Jin Tongsheng Chen Jinsong Hu Chao Zhou Chunlei Yang Qijie Liang Xugang Guo Weimin Li Weiqiang Chen Yan Jiang MOE Key Laboratory of Laser Life Science&Guangdong Provincial Key Laboratory of Laser Life Science Guangzhou Key Laboratory of Spectral Analysis and Functional ProbesCollege of BiophotonicsSouth China Normal UniversityGuangzhou 510631GuangdongChina school of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Songshan Lake Materials Laboratory Dongguan 523429GuangdongChina department of Materials Science and Engineering Guangdong Provincial Key Laboratory of Functional Oxide Materials and DevicesSouthern University of Science and TechnologyShenzhen 518055GuangdongChina Beijing Advanced Innovation Center for Soft Matter Science and Engineering College of Chemical EngineeringCollege of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China department of physics Liaoning UniversityShenyang 110036LiaoningChina Beijing National Laboratory for Molecular Sciences(BNLMS) Institute of ChemistryChinese Academy of SciencesBeijing 100190China School of physics and Materials Science Guangzhou UniversityGuangzhou 510006GuangdongChina Shenzhen Institute of Advanced Technology Chinese Academy of SciencesShenzhen 18055GuangdongChina

Near-infrared(NIR)transparent inverted all-inorganic perovskite solar cells(PSCs)are excellent top cell candidates in tandem *** essential challenge is the replacement of metal contacts with transparent conductive oxide(TCO)electrodes,which requires the introduction of a buffer layer to prevent sputtering *** this study,we show that the conventional buffers(i.e.,small organic molecules and atomic layer deposited metal oxides)used for organic-inorganic hybrid perovskites are not applicable to all-inorganic perovskites,due to non-uniform coverage of the vulnerable layers underneath,deterioration upon ion bombardment and moisture induced perovskite phase transition,A thin film of metal oxide nanoparticles by the spin-coating method serves as a non-destructive buffer layer for inorganic ***-inorganic inverted near-infrared-transparent PSCs deliver a PCE of 17.{3.%and an average transmittance of 73.7%between 780 and 12.0 *** combination with an 18.56%Cu(In,Ga)Se_(2) bottom cell,we further demonstrate the first all-inorganic perovskite/CIGS {3.T tandem solar cell with a PCE of 2{3.75%,which exhibits excellent illumination stability by maintaining 86.7%of its initial efficiency after 1{3.0 *** non-destructive buffer lays the foundation for efficient and stable NIR-transparent inverted inorganic perovskite solar cells and perovskite-based tandems.

关键词： CsPbI_(3.perovskite Inverted perovskite solar cells Tandem solar cells Buffer layer Stability