Recrystallisation of amorphous natural brannerite through annealing: The effect of radiation damage on the chemical durability of brannerite

An amorphous natural brannerite sample was chosen to study the annealing of the radiation damage through thermal recrystallisation, and subsequently to evaluate the effect of radiation damage on its aqueous durability. Microstructural characterisation of the natural brannerite revealed minor alteration along the rim of the crystal and within cracks. The formation of UO₂ particles and soluble Pb–Ca-rich aluminosilicate glass is responsible for the higher U and Pb releases from the recrystallised brannerite. In general, natural brannerite has been shown to be resistant to dissolution over geological time, therefore minor brannerite inclusions in ceramic formulations for immobilisation of actinide-rich radioactive wastes should not have a detrimental effect on the long-term chemical durability of the wasteforms.     

地层测试资料在实际应用中若干问题浅析

华北油田冀中地区在十几年实践过程中，陆续开展了200多层次地层测试（或三开抽汲）及该试油层常规抽汲试油工作。通过对1300次测试资料特别是对200层复试资料的分析对比，认为测试资料对自喷层和中高产非自喷井是准确的，可以不必进行三开抽汲。对井壁深部污染、低渗透和特低渗透层还存在一些偏差，为解决探井中一些疑难问题，需要配合抽汲。     

Spray deposition process study of SnO2silicon solar cells using orthogonal experimental design

With the “orthogonal experimental design” (OED), the dependence of conductivity and transparency of tin oxide films and open circuit voltage V_oc of SIS solar cells on the spray deposition process factors was studied. The OED technique was found to be a powerful method for realizing the best factor combination. Using OED, curves were obtained which clearly depict the effects of each factor on the SIS characteristics. The results of the experiments also illustrate exactly which variation in fabrication technique most affects the sheet resistance, V_oc, and film transparency. Under the optimal combination of conditions, a thin film doped with NH₄F was obtained, with about 90% transmission and a sheet resistance of about 80 Ω/□, along with an SIS structure with a V_oc of about 0.61 V.     

新城金矿采场落矿控制爆破技术

新城金矿为蚀变岩型金矿床,由于受地质构造影响,顶板稳定性较差,局部和较大面积的顶板冒落现象时有发生,为了解决采场顶板安全问题和提高落矿主要技术经济指标而进行了“上向水平分层尾砂胶结充填法采场控制爆破技术”的试验研究工作,试验达到了预期效果。     

变焦距镜头变倍组和补偿组移动导轨的设计

本文通过典型变焦距镜头的实例和图形,详细介绍了机械补偿变焦距镜头几种常用的变倍组和补偿组在变焦过程中往复运动导轨的结构形式,及其各种结构形式的优缺点。并论述了设计各种形式导轨机构应注意的问题。     

Linear periodically time-varying discrete-time systems: Aliasing and LTI approximations

Linear periodically time-varying (LPTV) systems are abundant in control and signal processing; examples include multirate sampled-data control systems and multirate filter-bank systems. In this paper, several ways are proposed to quantify aliasing effect in discrete-time LPTV systems; these are associated with optimal time-invariant approximations of LPTV systems using operator norms.     

大禹渡扬水工程枢纽沉沙池存在问题原因分析及对策

大禹渡扬水工程枢纽沉沙池是解决枢纽二级站水泵磨损及灌区渠道淤积的关键工程。现沉沙池沉沙效率低下，严重制约了灌溉效益的发挥。本文从沉沙池的建造历史、工程地质、池身结构、泥沙淤积等方面对沉沙池存在的问题进行了综合分析。     

Trace elements in human transitory milk. Variation caused by biological attributes of mother and infant

Multielement analysis was performed on human milk collected on 5-9-d postpartum from 51 Japanese females using inductively coupled plasma (ICP) mass spectrometry (MS), ICP atomic emission spectrometry (ICP-AES) and fluorometry. Thirty-one elements were detected by these analytical methods in milk. Twelve elements (Na, Mg, P, S, K, Ca, Cu, Zn, Se, Sr, Rb, and Mo) were detected in all of the samples. Al, Cs, and Ba were the elements detected by ICP-MS in more than half of the samples. Multiple regression analysis extracted biological attributes of mother and infant, such as maternal stature, maternal wt, or infant's birth wt, as statistically significant factors contributing to the variation in elemental concentration in milk. However, the rates of contribution were small in all cases. It was concluded that the biological attributes of mother and infant examined in this study were not the major factors that contribute to elemental variation in human milk.     

热处理工艺对冲击曲线的影响

通过ＳＡ５１５Ｇｒ．７０钢的不同温度正火和１３ＭｎＮｉＭｏＮｂＲ钢正火不同温度回火试样的示波冲击试验，研究了不同热处理工艺对冲击曲线的影响。     

频率/待测量变换的GAL、ERROM设计方法

本文提出了以通用阵列逻辑器件 GAL 和只读存贮器 EPROM 为核心器件的频率/待测量变换的设计方法。配以数字式传感器及用最小二乘法编制的曲线自动分段拟合程序生成的 EPROM 中的数据,可用于力、温度、光强等非电量的测量显示和控制。这种装置与采用微处理器的电路相比,有相同的测量精度,电路简单,而且保密性好.