低扬程贯流式泵站启动扬程的计算

将泵站从启动至正常运行分为4个阶段,进行泵站启动扬程的分析计算。指出影响泵站启动扬程的主要因素有泵站启动时进水池和出水池的水位差、出水流道工作闸门的开启速度、出水流道的结构布置。通过对贯流式泵站启动过程进行分析,运用水力学原理,就泵站启动扬程的主要影响因素提出一种分析计算方法。以淮安第三抽水泵站为例进行泵站启动扬程分析及计算,所得结果与泵站的实际启动运行情况基本吻合。     

Effect of Ar ion irradiation on structural and optical properties of e-beam evaporated cadmium telluride thin films

CdTe thin films were prepared using e-beam evaporation technique. The prepared films were irradiated by Ar⁺ ions at different fluencies using multipurpose aluminum (Al) probe as in-situ. This could also be used in ion bombardment for cleaning the substrate prior to coating. The as grown and Ar⁺ ion irradiated films were confirmed to be of polycrystalline nature with X-ray technique. Ar⁺ ion irradiation enhances the growth of (1 1 1) oriented CdTe crystals and the Cd enrichment on the surface of CdTe thin films. Higher Ar⁺ ion flux helps to grow (2 2 0) oriented CdTe thin film. A considerable change in structural parameters like crystallite size, lattice parameter, internal strain, etc. could be observed as a result of high Ar⁺ ion flux. The applied in-plan stress in both as grown and irradiated film was identified to be of tensile nature. The applied stress was observed between 0.016 and 0.067 GPa for all Ar⁺ ion irradiated samples. As a result of the Ar⁺ ion irradiation, the in-plan stress varies between 1.38×10⁹ and 5.58×10⁹ dyn/cm². The observed bad gap was increased for higher Ar⁺ ion flux. It shows the effect of Ar⁺ ion irradiation on the modifications of optical properties. The observed results were encouraging on the use of simple multipurpose Al probe for Ar⁺ ion irradiation process as in-situ.     

Conjugate‐optical retroreflector display system: Optical principles and perceptual issues

Abstract— Conjugate‐optical retroreflector (COR) display systems have the potential for providing inexpensive high‐resolution imagery in a head‐mounted display (HMD) configuration. There are several perceptual issues, however, that need to be addressed before a COR display system can be used effectively. One issue is the choice of projected‐image location relative to the retroreflective screen, which is determined by the convergence angle between the binocular channels of the COR display. Another issue involves visual half‐occlusions, which can occur when a portion of a stereoscopic image is visible to only one eye, as may occur in any HMD. If half occlusions are simulated in a COR display in a way that is inconsistent with natural viewing, undesirable perceptual effects may result. In the present paper, we first describe, the optical principles that underlie the COR display system. We then discuss the importance of binocular convergence and describe a COR display configuration that eliminates inconsistencies in the depth cues provided by displayed surface properties and halfocclusions.     

Fine-sized BaMgAl10O17:Eu phosphor powders prepared by spray pyrolysis from the spray solution with BaF2 flux

Fine-sized BaMgAl₁₀O₁₇:Eu²⁺ phosphor powders with plate-like morphology were prepared by spray pyrolysis process. The effects of ratio of BaF₂ and Ba(NO₃)₂ used as the source materials of Ba component on the morphological and optical properties of the BaMgAl₁₀O₁₇:Eu²⁺ phosphor powders were investigated. BaF₂ was used as the flux material as well as the source material of Ba component. The phosphor powders prepared from the spray solution with the same mole concentrations of BaF₂ and Ba(NO₃)₂ had fine size, plate-like morphology and narrow size distribution. The addition of BaF₂ as the source material of Ba component increased the photoluminescence intensities of the phosphor powders. The phosphor powders prepared from the spray solution with the ratios of BaF₂ and Ba(NO₃)₂ larger than 1 had the similar photoluminescence intensities to that of the commercial product.     

宝鸡峡魏家堡枢纽滚水坝下游消能优化设计

主要论证了魏家堡渠首枢纽除险加固工程滚水坝下游消能采用底流消能的合理性,并通过试验,证明了此种消能方式消能效果良好,且具有投资省、施工方便等经济效益.     

瓶装啤酒在装箱过程中酒标破损现象及其解决方法

本文叙述了酒标在装箱机过程中的破损现象，探讨了解决问题的办法，提出了处理措施。实践后的情况表明酒标破损现象得到了有效的防止     

Fluorescence line narrowing study of Cr ions in cordierite glass nucleating MgAl2O4 nanocrystals

The luminescence of Cr³⁺ ions in cordierite glass nucleating MgAl₂O₄ nanocrystallites has been investigated. The time resolved fluorescence line narrowing measurements and the temperature dependence of the homogeneous line width show that most Cr³⁺ ions are inside the nanocrystallites. Cr³⁺ ions occupy non-equivalent crystal sites, due to the Mg²⁺–Al³⁺ inversion effect. The values of the homogeneous line width compare well with those of previous studies in crystals. No surface effect has been observed due to the large size of the crystals.     

Radio frequency-induced polarization of ultra-cold neutrons or how to pump a two-level system

The well-known technique of optical pumping can be used to polarize a neutron beam in a transient way. In our experiment we demonstrate that an unpolarized beam of ultra-cold neutrons (UCN), interacting solely with a set of magnetic fields can become polarized without losing the “wrong” spin component.     

流溪河水电厂2号机组水导瓦温度过高的分析与处理

流溪河水电厂2号机组水导瓦温度过高,进行多次处理都没有达到预期效果,为了彻底解决问题,机组提前大修。介绍了水导轴承的结构和2号机组的基本运行情况,阐述了2号机组水导瓦温度过高问题的历次处理情况。根据前期处理情况,着重检查了会引起机组轴线变化的推力头、卡环和约束转轴受力的导轴承,最终查出水导瓦温度升高是由于卡环、推力头松动和下导瓦背的抗顶块硬度偏低所引起。针对找出的问题进行处理,彻底解决了2号机组水导瓦温度过高的问题。     

光纤延迟线长度编码优化设计

在光纤延迟测向激光告警系统中，光纤延迟线是用来连接光学接收系统和光电转换系统的．起到传输光、延迟光、对光信号进行编码的作用。由于光纤延迟线的长度不同，光学窗口接收到的激光脉冲产生不同的时间延迟．从而实现激光方位信息到时间信息的转变。光纤延迟线的长度对激光告警器的体积、光学损耗、虚警率等因素有着直接的影响，在此利用激光脉冲的相关特性，通过最优化理论对光纤延迟线进行排列组合．提出了光纤延迟线长度编码的优化设计方法，通过对相关理论的分析与计算．得到了一个全向矩阵的排列方式，从而得出了相应的排列原则。按照该原则对光纤延迟线进行排列组合，从理论上得到了最优的光纤延迟线总长度值，为激光测向告警器的优化设计提供了重要的理论依据。