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991.
Ines Klugius Rebekah Miller Aina Quintilla Theresa M. Friedlmeier David Blázquez‐Sánchez Erik Ahlswede Michael Powalla 《固体物理学:研究快报》2012,6(7):297-299
We investigate a process used for the selenisation of particle‐based precursors to prepare low‐cost Cu(In,Ga)(S,Se)2 (CIGS) solar cells. It is suitable for high throughput with a short optimum selenisation duration of 3–5 min and employs a rapid thermal annealing system with elemental selenium vapour. Homogeneous crack‐free Cu(In,Ga)S2 precursor films of up to 1 µm are obtained via doctor blading. The high selenium vapour pressure in the selenisation reaction chamber results in the formation of a compact Cu(In,Ga)(S,Se)2 layer on top of a carbon‐rich underlayer. In order to investigate the phase development in the film, the selenisation process was interrupted at different stages and the samples were monitored via XRD and surface‐sensitive Raman measurements. We find the formation of a polycrystalline Cu(In,Ga)Se2 phase already after 1 s at the target temperature of 550 °C. Furthermore, the effect of initial precursor thickness on solar cell parameters is discussed. Complete solar cells are prepared by conventional methods, leading to conversion efficiencies well above 8%. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
992.
S. P. Bautin 《Journal of Applied Mechanics and Technical Physics》2009,50(4):576-583
The Kuropatenko model for a multicomponent medium whose components are polytropic gases is considered. It is assumed that,
as x → ±∞, the multicomponent medium is in a homogeneous state with constant gas-dynamic parameters — velocity, pressure,
and temperature. For the traveling wave flows, conditions similar to the Hugoniot conditions are obtained and used to uniquely
determine the flow parameters for x → −∞ from the flow parameters x → +∞ and traveling wave velocity.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 4, pp. 39–47, July–August, 2009. 相似文献
993.
A version of Hill's lemma for Cosserat continuum 总被引:4,自引:0,他引:4
On the basis of Hill's lemma for classical Cauchy continuum, a version of Hill's lemma for micro-macro homogenization modeling of heterogeneous Cosserat continuum is presented in the flame of average-field theory. The admissible boundary conditions required to prescribe on the representative volume element for the modeling are extracted and discussed to ensure the satisfaction of Hill-Mandel energy condition and the first-order average field theory. 相似文献
994.
995.
研究了氧平衡及爆炸下极限条件对燃料空气炸药(Fuel Air Explosive,FAE)云雾爆轰半径的影响。由固相FAE燃料的氧平衡及爆炸下极限条件,导出一次引爆型固相FAE云雾爆轰半径计算公式,并从理论上给出了FAE云雾爆轰半径的范围。通过对FAE爆炸场超压的测量及对FAE爆炸过程高速摄像分幅照片的定量分析,得到一次引爆型固相FAE的云雾爆轰半径,并将其与计算的云雾爆轰半径进行了对比,计算的云雾爆轰半径与试验值是一致的。研究结果表明,FAE燃料负氧越多,对应的云雾爆轰半径值越大;燃料爆炸下极限值越小,对应的云雾爆轰半径值越大,且固相FAE的爆轰半径不超过爆炸下极限条件爆轰半径。FAE中的高效燃料可以通过氧平衡以及爆炸下极限条件来选择,以此提高FAE的功率。 相似文献
996.
Kalabin et al. (Numer. Heat Transfer A 47, 621-631, 2005) studied the unsteady natural convection for the sinusoidal oscillating wall temperature on one side wall
and constant average temperature on the opposing side wall. The present article is on the unsteady natural convective heat
transfer in an inclined porous cavity with similar temperature boundary conditions as those of Kalabin et al. The inclined
angle of the cavity is varied from 0° to 80°. The flow field is modeled with the Brinkman-extended Darcy model. The combined effects
of inclination angle of the enclosure and oscillation frequency of wall temperature are studied for Ra* = 103, Da = 10−3, , and Pr=1. Some results are also obtained with the Darcy–Brinkman–Forchheimer model and Darcy’s law and are compared with the present
Brinkman-extended Darcy model. The maximal heat transfer rate is attained at the oscillating frequency f = 46.7π and the inclined angle . 相似文献
997.
998.
《中国颗粒学报》2008,6(6)
Discrete element method (DEM) models to simulate laboratory element tests play an important role in advancing our understanding of the mechanics of granular material response, including bonded or cemented, particulate materials.Comparisons of the macro-scale response observed in a real physical test and a "virtual" DEM-simulated test can calibrate or validate DEM models.The detailed, particle scale information provided in the DEM simulation can then be used to develop our understanding of the material behaviour.It is important to accurately model the physical test boundary conditions in these DEM simulations.This paper specifically considers triaxial tests as these tests are commonly used in soil mechanics.In a triaxial test,the test specimen of granular material is enclosed within a flexible latex membrane that allows the material to deform freely during testing, while maintaining a specified stress condition. Triaxial tests can only be realistically simulated in 3D DEM codes, however analogue,2D, biaxial DEM simulations are also often considered as it is easier to visualize particle interactions in two dimensions. This paper describes algorithms to simulate the lateral boundary conditions imposed by the latex membrane used in physical triaxial tests in both 2D and 3D DEM simulations.The importance of carefully considering the lateral boundary conditions in DEM simulations is illustrated by considering a 2D biaxial test on a specimen of frictional unbonded disks and a 3D triaxial test on a bonded (cemented) specimen of spheres. The comparisons indicate that the lateral boundary conditions have a more significant influence on the local,particle-scale response in comparison with the overall macro-scale observations. 相似文献
999.
Ocean waves travel deep into ice fields in the polar regions, both affecting the formation of sea-ice and causing its break-up. Recently, it has been shown that a relatively simple linear water and bending wave theory can predict the decay rate of the wave energy travelling through fractured ice sheets and floes at the geophysically important wave periods of 6–15 s. That work used simple free-edge conditions. A possible improvement to the current model is to better represent the effective connection due to partially frozen cracks that occur in practice. The Wiener–Hopf technique gives explicit formulae for the velocity potential and surface deflection, expressed as series expansions over the modes of the elastic plate floating on water of finite depth, with the coefficients in the expansion given as functions of four constants. These constants are determined by a system of four linear equations, represented by a 4-by-4 matrix and a four-element vector. The elements of the matrix are given as explicit functions of relationship between edge conditions. General connections between ice sheets may be interpreted as a vertical and a rotational spring providing transition conditions for the shear force and the bending moment. The reflection and the transmission of waves can then be simply calculated as direct functions of the connection conditions. Conversely, reflected and transmitted waves allow complete characterization of the effective connection conditions at a material discontinuity. 相似文献
1000.
应用非晶的Ti-Al薄膜为导电阻挡层,采用射频磁控溅射法和溶胶-凝胶法在Si衬底上制备了La_(0.5)Sr_(0.5)CoO_3/Pb(Zr_(0.4),Ti_(0.6))O_3/La_(0.5)Sr_(0.5)CoO_3/Ti-Al/Si (LSCO/PZT/LSCO/Ti-Al/Si)异质结,研究了550 ℃常规退火(CTA)和快速退火(RTA)工艺对LSCO/PZT/LSCO/Ti-Al/Si结构和性能的影响.实验发现非晶Ti-Al薄膜在经过不同退火工艺后仍具有非晶结构,快速退火6 min的样品具有较好的物理性能.在418 kV/cm的外加电场下,LSCO/PZT/LSCO电容器的剩余极化强度和矫顽电场强度分别为22 μC/cm~2和83 kV/cm.LSCO/PZT/LSCO电容器的漏电行为不依赖于退火工艺,当电场强度低于46.7 kV/cm时为欧姆导电,高于46.7 kV/cm时为肖特基导电机制. 相似文献