网络展开图与符号网络分析

采用封闭网络模型,按照电路元件参数,采用开路、短路和着色运算,将电路图逐层分解,得到网络展开图.给出网络展开图的概念和运算规则,指出网络展开图中从根到末稍每个路径的值就是网络行列式展开式中的一个有效项,从而由网络展开图得到符号网络函数.该方法直接对电路图进行运算,不需要建立任何形式的电路方程和行列式,适用于一般的有源电路,而且能生成各种类型的网络函数.     

MEMS移相器及其在微型通信系统中的应用

从传统移相器的构造和原理出发，进一步分析了MEMS移相器的结构、特性。结果表明，MEMS移相器具有传统移相器所无法比拟的体积小、损耗小、成本低、频带宽、易于集成等突出优点。随着高阻硅衬底在微波领域应用的扩展，MEMS移相器介质损耗大幅度降低，将能与信号处理电路一同集成于硅衬底上，便于相控阵雷达等通信系统实现微小型化。     

The corrosion behavior of sputter-deposited aluminum-tungsten alloys

Thin films on aluminum-tungsten alloys were prepared by co-deposition of pure aluminum and pure tungsten, each sputtered by an independently controlled magnetron source, on glass and sapphire substrates. Completely amorphous films were obtained in the Al₈₀W₂₀-Al₆₇W₃₃ composition range. Passivity and corrosion behavior of amorphous Al-W alloys were investigated in 1 M deaerated hydrochloric acid solution using polarization and impedance spectroscopy measurements and have been correlated with the properties of pure alloy components. Tungsten and sputter-deposited Al-W thin films are inherently passive materials while aluminum undergoes pitting corrosion in hydrochloric acid solution. The passive film formed at the OCP on each alloy possesses excellent electric and dielectric properties comparable to those of the isolating film on tungsten. The absolute impedance increases with increasing tungsten content in the alloy. According to electrochemical polarization measurements, alloying Al with W in solid solution significantly enhances the material's resistance to pitting corrosion by shifting the breakdown potential above 2000 mV (Al₆₇W₃₃) and lowering the corrosion rate at the OCP by more than two orders of magnitude. The most likely mechanism explaining the passivity of amorphous Al-W alloys, the Solute Vacancy Interaction Model (SVIM), involves the formation of complexes between highly oxidized solute atoms (W⁺⁶) and mobile cation vacancies, which restrict the transport of Cl⁻ through the oxide film and inhibit its breakdown in hydrochloric acid solution. The role that film stress relaxation effects and microscopic defects in amorphous Al-W films, of the some composition, and deposited on various substrates play in their corrosion resistance is discussed.     

有水气藏开发早期可采储量的评价方法

有水气藏是天然气藏中的一个基本气藏类型，其采收率受多种因素的影响，如地面集输压力、井筒混合气水流动的液柱压力和储层物性等，目前普遍采用经验取值、物质平衡和气藏数值模拟等方法进行研究，但由于受开发评价阶段试采资料偏少和气藏数值模拟无法模拟井筒流动等因素的影响，早期采收率计算往往偏差较大，针对这些问题，从气田开发一体化的特点出发，提出了一种全面考虑地层→井筒→地面流动条件下，有水气藏（含凝析有水气藏）发废弃压力的计算方法，发展了利用物质平衡早期预测有水气藏采收率的理论，方法可靠、适用性强，能够推广应用。     

钻井液用BDY-1便携式堵漏仪

在堵漏过程中，对堵漏材料和堵漏浆配方的优选是决定堵漏成功的关键。为了能在现场对堵漏进行评价，研制出BDY－1便携式堵漏仪，该堵漏仪主要由不锈钢钢柱圈钢，压力表等加工而成，该堵漏仪体积小，重量轻，价格低，仅为国产堵漏仪的1／20。试验结果表明BDY－1便携式堵漏仪操作简便，可快速对堵漏材料进行评价并筛选出堵漏配方；数据重复性好，准确可靠，能达到进口或国产堵漏仪的水平；在模拟漏层选定后，可采用多套压力梯度，对堵漏浆封堵效果进行评价，在压力梯度选定后，可评价堵漏浆对不同类型漏层的封堵效果；如果扩大压力范围，可对封堵后的漏层进行破裂试验，从而确定合理的钻井施工参数；适用现场操作和应用。     

沥青延度与流变特性关系研究分析(一)

通过对两种基质沥青进行不同温度及不同速率下的延度试验，找出它们的流变特性，并从微观上进行分析，最后与路用性能相联系，又通过TFOT试验找出流变特性对耐老化性之间的关系，最后得出，沥青的流变特性可通过延度试验来表征，它能够较好地反映沥青的路用性能。     

Utilities in the sky?: Comparison of space-based and terrestrial solar power systems

Could huge arrays of space-based solar power systems one day supply utility scale electricity to the electric power grid on earth? How realistic a possibility is this option for alternative energy supply at the moment? Finley R. Shapiro, USA compares space-based and terrestrial solar power systems.