Molybdenum thin film deposited by in-line DC magnetron sputtering as a back contact for Cu(In,Ga)Se2 solar cells

In this paper, we reported the effect of the power and the working pressure on the molybdenum (Mo) films deposited using an in-line direct current (DC) magnetron sputtering system. The electrical and the structural properties of Mo film were improved by increasing DC power from 1 to 3 kW. On the other side, the resistivity of the Mo films became higher with the increasing working pressure. However, the adhesion property was improved when the working pressure was higher. In this work, in order to obtain an optimal Mo film as a back metal contact of Cu(In,Ga)Se₂ (CIGS) solar cells, a bilayer Mo film was formed through the different film structures depending on the working pressure. The first layer was formed at a high pressure of 12 mTorr for a better adhesion and the second layer was formed at a low pressure of 3 mTorr for a lower resistivity.     

Lagrange-type duality in DC programming

We show a Lagrange-type duality theorem for a DC programming problem, which is a generalization of previous results by J.-E. Martínez-Legaz, M. Volle [5] and Y. Fujiwara, D. Kuroiwa [1] when all constraint functions are real-valued. To the purpose, we decompose the DC programming problem into certain infinite convex programming problems.     

Meter-long CeO2/YSZ/Y2O3 buffer layers for YBCO coated conductors using DC reactive sputtering

This paper reports CeO₂/YSZ/Y₂O₃ buffer layers deposited on biaxially textured NiW substrates by DC reactive sputtering in a reel-to-reel system. The effect of partial pressure of water vapor (P_H2O) on surface morphology and orientation of the Y₂O₃ films was examined. The obtained CeO₂/YSZ/Y₂O₃ buffer layers exhibit a highly biaxial texture, with in- and out-of-plane FWHM values respectively in the range of 6.0–7.0° and 4.5–5.5°. Crystallographic consistency of CeO₂/YSZ/Y₂O₃ along meter length is excellent. Atomic force microscope observation (AFM) reveals a smooth, continuous and crack-free surface with a Root-mean-square roughness (RMS) lower than 10 nm.     

Enhancement of electrical properties due to Cr substitution in Co-ferrite nanoparticles synthesized by two chemical techniques

Nanocrystalline cobalt ferrites with nominal composition CoCr_xFe_2−xO₄ ranging from x=0.0 to 0.5 with step increment of 0.25 were prepared by sol–gel auto combustion and chemical co-precipitation techniques. A comparative study of structural, electrical and magnetic properties of these ferrites has been measured using different characterization techniques. Structural and micro-structural studies were measured using X-ray diffraction, Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy and atomic force microscopy. Crystallite sizes of the series are within the range of 12–29±2 nm. Lattice parameters decrease by increasing Cr³⁺ concentration. FTIR confirms the presence of two lattice absorption bands. DC electrical resistivity increases to a value of ∼10¹⁰ Ω-cm with increase in Cr³⁺ concentration, but the most significant increase is in samples prepared by sol–gel combustion. Dielectric properties have been measured as a function of frequency at room temperature. Dielectric loss decreases to 0.1037 and 0.0108 at 5 MHz for chemical co-precipitation and sol–gel combustion, respectively. Impedance measurements further helped in analyzing the electrical properties and to separate the grain and grain boundary resistance effects using a complex impedance analysis. Magnetic parameters were studied using a vibrating sample magnetometer in the applied field of 10 kOe. The saturation magnetization decreased from 63 to 10.8 emu/gm with increase in Cr³⁺ concentration.     

无机陶瓷膜纯化杏鲍菇多糖

为了提高杏鲍菇多糖的含量,用0.2μm的无机陶瓷膜对杏鲍菇多糖进行纯化,结果表明在25℃,0.02—0.08M Pa压差操作条件下,纯化后的杏鲍菇多糖含量为62%,并且可以除去大部分不溶物和蛋白质胶体等大分子杂质。采用漂洗、碱洗、酸洗,可使膜的清水通量恢复率达到95%以上。     

Preparation of modified polymer blend and electrical performance

In this study, a modified binary polymer blend made up of polycarbonate and polystyrene blend has been prepared by loading of aluminum oxide (Al₂O₃) as a dopant. The role of alumina with polymer blend system was addressed in view of interfacing criteria. The filler concentration of modified blend was taken as 5, 10, and 15%. The morphological, thermal, and electrical properties were characterized by various techniques. Optical microscopy confirms the homogenous dispersion of Al₂O₃ in blend. The presence of alumina was detected by subatomic level using atomic force microscope (both two and three dimensional approach). The differential scanning calorimetric thermographs demonstrate decreasing softing point as function of alumina loading. The dielectric properties such as dielectric constant, loss, and electrical modulus were studied under DC bias. The effect of DC bias exhibits significant changes at low amount of Al₂O₃. The dielectric polarization supports Maxwell Wagner (MW) theory due to low frequency response. 15% Al₂O₃ gives the highest dielectric constant (ε′) value (3.5?×?10⁵) at 10 Hz. The polymer modified blend with Al₂O₃ may be used as a one of the best dielectric medium.     

On Global Optimality Conditions and Cutting Plane Algorithms

We discuss global optimality conditions and cutting plane algorithms for DC optimization. The discussion is motivated by certain incorrect results that have appeared recently in the literature on these topics. Incidentally, we investigate the relation of the Tikhonov reciprocity theorem to the optimality conditions for general nonconvex global optimization problems and show how the outer-approximation scheme developed earlier for DC programming can be used to solve a wider class of problems.     

新疆薰衣草精油化学成分的研究

本文用气相色谱-质谱联用的方法,分别鉴定出了新疆伊犁薰衣草精油中的27种化合物和印度进口薰衣草精油中的36种化合物。     

脉管制冷机直流机理研究和抑制方法探讨

双向进气脉管制冷机中存在的直流流动不仅增加了冷端换热器的负载 ,降低了脉管制冷机的性能 ,而且还是引起脉管制冷机制冷温度不稳定的一个重要原因。文中从流体网络理论出发 ,分析了直流产生的机理 ,对目前各种抑制方法进行了探讨 ,指出了进一步研究的方向。     

一种改进的谐振参数扰动法及其在DC/DC变换器混沌控制中的应用

种改进的谐振参数扰动法来控制混沌，该混沌控制方法引入了基于非线性映射的调制，其控制目标可以是任意周期的轨道，而不是原混沌吸引子中的嵌入轨道。作为一个应用实例，文中描述了该方法在电流模式控制dc/dc变换器中的应用结果。