LaNiO3 and Cu3Ge contacts to YBa2Cu3O7-x films

Metallization of high-T_c superconductors using low resistivity metal oxides and Cu-Ge alloys has been investigated on high quality pulsed laser deposited epitaxial YBa₂Cu₃O_7-x (YBCO) films. Epitaxial LaNiO₃ (LNO) thin films have been grown on YBCO films at 700°C using pulsed laser deposition. The specific resistivity of LNO was measured to be 50 μΩ-cm at 300K which decreases to 19 μΩ-cm at 100K indicating good metallicity of the LNO films. The contact resistance of LNO-YBCO thin film interface was found to be reasonably low (of the order of 10^-4Ω-cm² at 77K) which suggests that the interface formed between the two films is quite clean and LNO can emerge as a promising metal electrode-material to YBCO films. A preliminary investigation related to the compatibility of Cu₃Ge alloy as a contact metallization material to YBCO films is discussed. The usage of other oxide based low resistivity materials such as SrRuO₃ (SRO) and SrVO₃ (SVO) for metallization of high-T_c YBCO superconductor films is also discussed.     

A1.3 μm strained quantum well laser on a graded InGaAs buffer with a GaAs substrate

We grew a 1.3 μm strained-layer quantum well (SL-QW) laser with InGaP cladding layers on a lattice-relaxation buffer layer by metalorganic vapor phase epitaxy. For the lattice-relaxation buffer, we used a compositionally graded InGaAs/GaAs structure. The significantly reduced surface roughness of the InGaP cladding layers achieved by supplying a large amount of H₂Se enables CW operation of our 1.3 μm SL-QW laser. We achieved a low threshold current of less than 10 mA and a high characteristic temperature of 100K around room temperature.     

各向异性地层重复压裂最优时机及影响因素分析

依据低渗透储层力学参数和渗流特点,建立了考虑地层各向异性的固-液耦合最佳重复压裂时机模型,提出了等应力点的概念。对多因素影响下的最佳重复压裂时机的研究表明,远场水平地应力差较小、弹性模量较大、初次裂缝长度和宽度较大、低渗透、初次改造后平均生产压差较大等影响因素对重复压裂产生新缝有利。将影响因素分为3类:①产生重复压裂新裂缝的影响因素;②仅影响最优重复压裂时机的因素;③可以忽略的因素。     

透明聚丙烯流变行为研究

分别考察了自主研制、进口、国产透明聚丙烯(PP)专用料ZPP,R 370 Y,J 301 G的流变行为.结果表明,ZPP,R 370 Y和J 301 G熔体均属于非牛顿型假塑性流体;R 370 Y专用料对温度的敏感性较大.成型加工时宜进行温度调整;ZPP和J 301 G专用料对剪切敏感性较大,成型加工时宜进行剪切速率或剪切应力的调整;透明PP专用料的相对分子质量及其分布对其表观黏度有一定影响;ZPP的各项力学性能均优于S 800型通用PP.     

垂直射孔井地应力及破裂压力研究

一般水力压裂井施工前都进行了射孔作业,不同的射孔参数可能会对压裂施工和压后产能产生不同程度的影响。应力分析是进行这类研究的基础,文章在国内外相关应力分析研究的基础上,运用解析方法研究了射孔后孔眼围岩的地应力分布,通过应力分布计算,结合抗拉破坏准则,对垂直射孔井水力压裂破裂压力进行了分析,得到了孔眼围岩应力分布和垂直射孔井水力压裂破裂压力的定性认识,可以为压裂井射孔工艺技术优化设计提供一定的指导。
     

随机裂缝性储层压裂特征实验研究

模拟了裂缝性储层的天然裂缝系统,利用大尺寸真三轴实验系统,分析了天然裂缝影响下的水力裂缝形态、压力曲线特征和滤失机理.实验结果表明,在天然裂缝系统中,裂缝扩展模式分为主缝多分支缝和径向网状扩展两种形式.在同一个天然裂缝系统中,主缝多分支缝扩展模式在水平主应力压差高的条件下占优势,压力曲线波动频繁,基本符合一维滤失特征;径向网状扩展模式在水平主应力压差低的条件下占优势,压力曲线平缓,属于二维滤失.进行了小型压裂估算最小地应力模拟,定义了天然裂缝主导的误差系数,在模拟出的上述天然裂缝条件下,平均误差系数为0.2.     

Thermodynamic-behaviour model for air-cooled screw chillers with a variable set-point condensing temperature

This paper presents a thermodynamic model to evaluate the coefficient of performance (COP) of an air-cooled screw chiller under various operating conditions. The model accounts for the real process phenomena, including the capacity control of screw compressors and variations in the heat-transfer coefficients of an evaporator and a condenser at part load. It also contains an algorithm to determine how the condenser fans are staged in response to a set-point condensing temperature. The model parameters are identified, based on the performance data of chiller specifications. The chiller model is validated using a wide range of operating data of an air-cooled screw chiller. The difference between the measured and modelled COPs is within ±10% for 86% of the data points. The chiller’s COP can increase by up to 115% when the set-point condensing temperature is adjusted, based on any given outdoor temperature. Having identified the variation in the chiller’s COP, a suitable strategy is proposed for air-cooled screw chillers to operate at maximum efficiency as much as possible when they have to satisfy a building’s cooling-load.     

An advanced zero emission power cycle with integrated low temperature thermal energy

An innovative zero emission hybrid cycle named HICES (hybrid and improved CES cycle) is presented in this paper. It can utilize fossil fuel and low quality thermal energy such as waste heat from industrial processes and solar thermal energy for highly efficient electric power generation. In the HICES cycle, natural gas is internally combusted with pure oxygen. External low quality thermal energy is used to produce saturated steam between 70 and 250 °C as part of the working fluid. The thermodynamic characteristics at design conditions of the HICES cycle are analyzed using the advanced process simulator Aspen Plus. The influences of some key parameters are investigated. The results demonstrate that the thermodynamic performances of the HICES cycle are quite promising. For example, when the external heat produced saturated steam is at 70 °C, the net fuel-to-electricity efficiency is 54.18% even when taking into account both the energy penalties to produce pure oxygen and to liquefy the captured CO₂. The incremental low temperature heat to electric efficiency is as high as 14.08% at the same time. When the external heat produced saturated steam is at 250 °C, the net fuel-to-electricity efficiency reaches 62.66%. The incremental low temperature heat to electric efficiency achieves 48.92%.     

大型旋转机械状态监测与故障诊断系统的设计

设计了计算机状态监测与故障诊断系统,系统是Windows界面下的状态监测与故障诊断系统,它在数据采集卡PCL 1800的支持下,可以完成振动信号的数据采集以及功率谱、倒谱、谱阵和相干函数分析等功能。能将数据转化成各种对应的图形。详细介绍了该系统的组成模块及其功能实现。它可以广泛应用于电力、石化、冶金、汽车和造船等国民经济重要部门,做振动的测试和分析。     

燃油锅炉改烧瓦斯气炉内流动和燃烧过程的数值模拟

1引言近年来,石化行业生产工艺的可燃副气量越来越多,如何利用这些气体燃料已成为石化行业节能和环保所面临的一项必须解决的任务。为了回收利用工业可燃副气,将现有的燃油锅炉改烧可燃副气或油气混烧是一项良好的节能措施。然而,燃料成份的改变、燃烧器喷射状况的不同以及炉膛