浅谈钢衬化学接触灌浆在发电厂房尾水管中的应用

蒙江流域黄花寨水电站发电厂房1～2#机组尾水钢衬及管型座外环已安装施工完成。由于施工条件限制及混凝土干缩特性的影响,对尾水锥管、管型座外环进行锤击检查,发现尾水锥管、管型座外环下半部,存在不同程度的脱空现象。为确保电站机组的安全运行,需对脱空部位进行化学接触灌浆处理。     

水泵水轮机飞逸工况下尾水管涡带演化研究

为研究水泵水轮机在飞逸工况下不同导叶开度时的水力不稳定性,以某抽水蓄能电站水泵水轮机为研究对象,基于Realizable k-ε湍流模型的非定常数值计算方法,对水泵水轮机七种不同导叶开度下的流动进行全流道计算。结合监测蜗壳进口、无叶区、转轮与顶盖之间以及尾水管处的压力脉动,研究了水泵水轮机在不同导叶开度下尾水管涡带的形态,及其对尾水管压力脉动的影响。结果表明:飞逸工况下,尾水管涡带与开导叶度关系密切;小开度下,涡带较明显且涡带形态不断撕裂重构并伴有局部回流;随开度增大,尾水管涡带的形态逐渐由紊乱无规则变为明显锥状,且随着开度的进一步增大涡带形状演变为粗壮螺旋涡带。大开度下,涡带近壁面旋向侧速度较大是导致直锥段壁面湍动能较大等能量损失的主要原因;尾水管涡带不断向下游输运,是造成水泵水轮机尾水管巨大压力脉动的关键因素。     

一种基于聚类分析的护听器筛选分类方法

对于长期佩戴护听器的人员,护听器不仅要求隔声效果好,而且舒适性也要很好。这样在考虑不同噪声频段和多技术参数的情况下,利用聚类理论对噪声护听器的多技术参数（噪声单值评价值、高频衰减值、中频衰减值、低频衰减值、加紧力、重量等）进行筛选分类研究,对于护听器的多参数综合选择具有重要意义。     

某抽水蓄能电站地下厂房热湿环境测试分析

水电站地下厂房的通风空调系统对维持厂房内的热湿环境,使其满足人员工作及设备运行的要求有着重要作用。为了对某抽水蓄能电站地下厂房的热湿环境进行评估,对主厂房各层空间空气的热湿参数及通风量进行测试,并结合室外天气状况得出室外天气对厂房内的热湿环境的影响。在测试过程中发现,其蜗壳层设备及管路表面结露问题严重。根据对结露现象的分析,提出相应的解决方案,为水电站地下厂房的热湿环境的调控提供参考。     

HHHT抽水蓄能电站地下主厂房母线层通风模型试验研究

通过HHHT抽水蓄能电站地下主厂房1：20缩尺模型来研究其母线层气流组织分布。在56m^3/h及112m^3／h的两种风量下,分别选择5种送风口方案1～5,对母线层工作区温度场及速度场进行测试。未封闭吊物孔、未安装接力风机时的温度分布标准差最大值为0．95,最小值为0．42：封闭吊物孔、安装接力风机后的温度分布标准差最大值为0．35,最小值为0．08。研究表明,封闭吊物孔、安装接力风机加强了母线层工作区气流组织分布的均匀性,双排对称布置送风口（方案5）为最佳送风口方案。研究结果为HHHT及相关电站地下厂房复杂气流的优化组织设计提供了参考依据。     

水工复杂曲面尾水管的几何建模与形态分析

尾水管是水工建筑物中比较复杂的空间曲面之一，采用计算机辅助设计软件Auto CAD及造型软件3DSMAX对尾水管进行拟实建模及形态分析，加深了人们对其复杂结构、曲面类型、工作原理的理解，提升了尾水管制图的精度，降低了设计难度。研究中所积累的技术与方法能够促进计算机拟实技术的发展，为更多水工曲面的研究提供借鉴，也可为其他领域的设计工作提供帮助。     

地下水电站交通进风洞热湿环境测试与分析

通过实地测试,在三个不同通风发热工况下,分析了某抽水蓄能电站交通进风洞对进入空气的热湿处理能力状况,重点叙述了交通进风洞的全热交换量和除湿量,以及洞深的不同对其热湿处理能力的影响,同时简单分析了实测过程中存在的冷热平衡问题及结露问题.     

CO2复叠式空气源热泵供暖运行测试

CO₂空气源热泵因其优秀的环保和热工性能，具有广阔的应用前景。本文以CO₂复叠式空气源热泵分布式集中供暖系统为研究对象，依据JGJ/T 177—2009《公共建筑节能检测标准》和JGJ/T 132—2009《居住建筑节能检测标准》对秦皇岛某公共建筑和石家庄某居住建筑的CO₂复叠式空气源热泵供暖系统开展运行测试研究，探究在低温环境下系统运行过程中检测不确定度及实际运行效果。通过不确定度分析，秦皇岛项目2#机组和石家庄项目2#机组制热性能COP在不同运行环境温度下相对合成标准不确定度范围分别为4.27%～5.87%及1.90%～4.36%,测试结果可信度高。测试结果表明：秦皇岛项目在室外日均温度-10.9～2.5℃的工况下，1#和2#机组实测日均COP范围分别为2.75～3.09和2.76～3.15。在室外最低温度-18℃时，1#和2#机组热COP仍可达到2.19及2.88。石家庄项目在室外日均温度-6.6～12.5℃的工况下，1#和2#机组实测日均COP范围分别为2.32～3.38和2.21～3.06;分析两个项目的检测结...     

抽水蓄能机组振动故障诊断专家系统

摘 要：本文根据抽水蓄能电站机组的特点,采用模块化思想,设计了一个关于抽水蓄能机组振动故障诊断专家系统,并对该系统的结构、关键功能模块、推理机的设计和软件实现过程进行了介绍,最后给出了该专家系统的实际应用案例。抽水蓄能机组故障诊断专家系统作为一种人工智能计算机程序,能够在一定程度上帮助现场故障诊断人员对机组的运行状态有一个较为深入的了解,它比较适用于复杂的、比较规范化的大型动态系统。     

一管多机布置抽水蓄能电站非线性动力学建模与瞬态分析

一管多机布置抽水蓄能电站存在共用管段引水系统,其中共用管段的水力耦合相互作用是抽水蓄能电站系统动力学建模的关键。考虑共用管段水力系统耦合作用,将其分解成多个仅依赖于各子管段流量的单变量函数,通过结合水泵水轮机组动态特性,建立一管多机布置抽水蓄能电站非线性动力学模型。利用数值模拟探究了两机在额定工况并列运行时,一机突甩全负荷在不同导叶关闭规律且另一机组在调速器PID控制下,对各支管内机组流量、水头、出力动态特性的影响规律。仿真结果表明正常运行机组出力和流量动态响应具有正相关关系,机组水头动态响应与其流量和出力具有负相关关系,且波动周期相近。突甩负荷机组水头与流量的动态响应与导叶关闭规律密切相关,突甩负荷机组水头波动程度始终高于正常运行机组水头,且两机组水头波动周期相近;研究结果为探究一管多机抽水蓄能电站系统瞬态动力学建模与稳定性调控提供理论参考。     

Crystallization and thermal properties of polyamide 6 composites filled with different nanofillers

The aim of this research is mainly to study the melting and crystallization behavior of polyamide 6 (PA6) when interacting with different nanofillers. The results show that the addition of nanofillers causes the increase of the peak temperature (T_p) during crystallization, which can be explained by the nucleation effect of the nanofiller. For PA6 and nanocomposites, the α crystal is the dominant crystalline phase. However, the γ form crystal appeared in PA6 containing montmorillonite (MMT) and SiO₂, while the crystallization did not appear in the composites with carbon nanotube (CNTs). For the PA6/CNTs nanocomposites, the length and surface properties of CNTs also had an effect on the crystallization of PA6. Although there are more -COOH groups on the surface of CNTs1^#, the crystallization degree of PA6/CNTs1^# is the lowest. The area of the melting peak of CNTs3^# is relatively large for a shorter size. The crystal-particle distribution is also varied for different dimensions of CNTs treated using three methods and the width of the melting peak of PA6/CNTs3^# is the largest.     

Thermal behaviour kinetic study of dihydroglyoxime and dichloroglyoxime

Glyoxime derivatives have increasingly gained attention because of their potential for generation of energetic materials. In this paper, the thermal behaviours of dihydroglyoxime (DHG) and dichloroglyoxime (DCG) in a nitrogen atmosphere were studied under non-isothermal conditions by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. The results showed that the decomposition of DCG occurs in two continuous steps, in the 160-230 °C temperature range. Each thermal degradation stage for DCG results an exothermic peak in the DSC curve. On the other hand, applying TG-DSC techniques indicates that DHG sublimates about 178 °C before it decomposes. Also, the influence of the different heating rates such as 5, 10, 15 and 20 °C min^− 1 on the thermal behaviour of both compounds was investigated. The results of DSC experiments indicate that the peak temperature of DCG decomposition and sublimation temperature for DHG were increased, as the heating rate was increased. The kinetic parameters such as activation energy and pre-exponential factor for each compound were found by means of the Kissinger method and were verified by the Ozawa-Flynn-Wall method. Based on the values of activation energy obtained by the Kissinger method, the first stage of DCG decomposition has an activation energy about 100 kJ mol^− 1 and the sublimation process for DHG has an activation energy about 259 kJ mol^− 1. Finally, the thermodynamic parameters (ΔG^#, ΔH^# and ΔS^#) for decomposition of DCG and sublimation of DAG were determined.     

Ethyl Cellulose-Solvent Phase Relationships Relevant to Coacervation Microencapsulation Processes

Abstract

Qualitative and quantitative solubility studies of ethyl cellulose, Type N-10, in 112 and 36 solvents respectively are reported. The relative contribution of dispersive, polar and hydrogen bonding intermolecular forces are depicted on two-dimensional and triangular solubility graphs. Phase separation phenomena may be explained in terms of the differences in both the solubility parameter (δ) and the polymer-solvent interaction parameter (χ_c) values between ethyl cellulose and each solvent. Coacervation occurs in very poor solvents with δ values just outside the solubility spectrum of ethyl cellulose

A mean value for the solubility parameter and critical interaction parameter (χ_c) for ethyl cellulose obtained from turbidity titration measurements were 9.39 ± 0.17 (cal/cm³)^½ and 0.38 ± 0.04 respectively. Gelation occurs with nonsolvents with δ values significantly outside the solubility spectrum and with correspondingly larger χ_c values. Flocculation was observed only in polar solvents in which large χ_c values occur

Theoretical values for the ethyl cellulose-solvent interaction parameters were calculated for 112 solvents. It is proposed these parameters can identify potentially useful solvents or solvent-nonsolvent systems for the preparation of microcapsules using coacervation     

Failure analysis of components in compressor vane

The paper presents a failure analysis of components damaged in compressor vane. In order to investigate the damage mechanism and failure causes of components, macroscopic and microscopic observations, microstructural investigations, chemical analysis and hardness measurement have been performed. The results show that the damaged components are caused by fractured blades of 1st stage rotor. In all 1st stage rotor blades, 1^# blade is fractured firstly, and is troublemaker in this incident. The fracture mechanism of 1^# blade fractured from blade root is due to first order bending vibration fatigue damage. The microstructure, hardness and chemical compositions of 1^# blade fracture, all which coincide with technical requirements. The bad shot peening qualities in the surface near blade fracture have important influence on fatigue failure.     

Short-lived fission products as a diagnostics tool for studying atom and ion behavior in a gas-based laser ion source

A striking difference between gamma spectra of neutron-rich Rh isotopes obtained with the laser ion source at the Leuven Isotope Separator On-Line facility has been observed depending on the mode of operation. Although the global production rate of ¹¹²Rh^g,m nuclei decreases considerably, the ratio between the productions of ¹¹²Rh^g and ¹¹²Rh^m increases strongly when no laser ionisation is used. This effect is caused by ¹¹²Ru atoms which decay during gas evacuation of the ion source gas cell, thereby producing ¹¹²Rh^g ions. The comparison in time behaviour of reaction produced ions, β-decay produced ions and laser produced ions makes it possible to study and characterise the different processes in the gas cell. The influence of these processes has to be considered when extracting nuclear information such as the relative feeding of different short-lived isomers and isotopes and fission cross-sections in a particular mass chain.     

冷藏车开门时车内温湿度变化实验研究

配送过程中冷藏车开门时的热质交换会引起车内空气温湿度的剧烈变化,这使得食品的品质难以得到保证.针对目前冷藏车开门卸货时存在的一些问题,进行了对比实验,对不同条件下的车内温度、相对湿度变化进行了分析,得出在开门时长一定的情况下车厢内外空气温差是影响车内温升的主要因素,采用PVC门帘可以有效地抑制车内温度升高,一定程度上保证食品安全.     

Study of lateral shocks observed during fork truck and pallet jack operations for the handling of palletized loads

This study measured the lateral impact levels that occur when fork trucks are used to handle palletized loads. The existing ASTM-D4003 standard on pallet marshalling recommends a 40 G, 10 ms shock or a 10G. 50ms shock to simulate impacts on pallet loads due to fork truck equipment. This study investigated the validity of these levels since no previous studies documenting these levels is provided in the ASTM standards.⁵ A set of ten impacts were conducted in the two different scenarios using boxes, bins and drums. These scenarios represent a palletized load on a fork truck impacting a similar stationary pallet load and an empty fork truck impacting a pallet load. Results are presented for each category of impacts performed in terms of average and maximum levels measured. The average peak acceleration for the data collected was 36 G and the average duration of impact was 4.3 ms. An analysis describing the limiting conditions for the shock acceleration G and the duration T as a function of the fork truck weight, impact speed, pallet weight and impact condition was determined. This showed that the impacts should have the product of maximum shock (in G) and duration (T) mms lying between 37.2 and 368 for half-sine shocks.     

High quality a-plane GaN films grown on cone-shaped patterned r-plane sapphire substrates

Planar nonpolar (112?0) a-plane GaN films have been grown by metalorganic chemical-vapor deposition directly on cone-shaped patterned r-plane sapphire substrates (PRSS) fabricated by dry etching. High-resolution X-ray diffractometers 2θ-ω scan confirmed that the films grown on PRSS are solely a-plane oriented, and the full width at half maximum values (FWHM) of the X-ray rocking curves for (112?0) GaN along [0001]_GaN and [11?00]_GaN were found to be 684 and 828″, respectively. As compared to the film grown on conventional r-plane sapphire substrate which typically has (112?0) omega FWHM values of 900 and 2124″ along [0001]_GaN and [11?00]_GaN respectively, the film grown on PRSS exhibits overall reduced omega FWHM values, and much smaller anisotropy behavior of crystallinity with respect to the in-plane orientation. The surface morphology is also improved by utilizing the PRSS technique. Cross-sectional transmission electron microscopy analysis shows that the density of threading dislocations has been greatly reduced from ~ 1.0 × 10¹⁰ cm^− 2 above the flat sapphire regions to ~ 1.0 × 10⁷ cm^− 2 above the protruding cone patterns. The improvement of crystal quality and the increase of light extraction efficiency by using cone-shaped PRSS technique lead to a strong enhancement in the light emission of a-plane GaN films. These results indicate that growth of a-plane GaN films on cone-shaped PRSS shows promise for use in high-quality and high-cost-performance nonpolar GaN based devices.     

The vibratory stress relief of a marine shafting of 35# bar steel

The marine shafting is made from a 35^# bar steel. The 35^# bar steel is named based on PR China national standard GB 699-88, “Quality carbon structure steel technical requirements,” the 35^# bar steel corresponds to 060A35, B.S. The bar steel was hot rolled, piled and air cooled; hot rolling, cooling and microstructure transformation formed macro residual stress in the bar steel. There is high macro residual stress in the 35^# (060A35, B.S.) bar steel. Worker shaped the bar steel into marine shafting with lathe. During machining, the macro residual stress releases and thus causes considerable deformation of the marine shafting.The vibratory stress relief is introduced to the bar steel that was shaped into marine shafting. The vibratory stress relief of the bar steel of the marine shafting was carried out. The tensile properties of the bar steel were measured before and after vibration. While the bar steel was vibrating, six different location axial surface vibratory stresses were measured with dynamic strain gauge; the axial surface vibratory stresses distributive curve is obtained. The macro residual stress was measured with X-ray stressmeter before and after vibration. The macro residual stress decreased notably by about 48%. The tensile properties changed slightly. The vibratory wave is a standing wave.The vibratory stress relief is valid for macro residual stress relieving of the bar steel of the marine shafting. The mechanism of the macro residual stress relieving by vibration on the bar steel of marine shafting is discussed. The “double-dynamic mechanism” is introduced to explain the course of macro residual stress relieving in the test.