CAE技术在汽轮机高温强度计算中的应用

为分析某百万千瓦超超临界汽轮机高压缸旋转部件在高温以及高离心力载荷下的强度状况,建立高压缸第一级动叶片的模型.根据蠕变试验数据,采用最小二乘法拟合幂蠕变方程中的各个参数,并详细介绍各参数的拟合、优化和验算过程;用CFD分析软件计算流体域内的对流传热系数并插值到有限元计算程序中,分析叶根倒角处危险区域的蠕变应力状况.数据验算结果表明,利用拟合数据计算得到的蠕变应力值与试验值比较接近,证明该方法可靠;CAE计算结果表明,叶根倒角处危险区域蠕变应力考核合格,并且有充足的安全裕量.     

VoiceXML语言解释器的设计与实现

VoiceXML语言是一种基于XML的标准对话标记语言,它是实现语音浏览网络模式的关键技术之一。该文介绍了VoiceXML语言的基本内容,设计了VoiceXML语言解释器的解释算法,并完成了对象树生成模块和语音解释模块的设计。     

一种基于混合硬化本构模型的汽轮机轮盘榫槽疲劳寿命预测方法

针对汽轮机转子轮盘的受力特点,以非对称载荷下材料的瞬态应力应变响应为基础,在内变量理论框架下,建立起某型汽轮机轮盘材料的率无关循环塑性本构模型;并结合局部应力应变法,进一步建立了基于混合硬化本构模型(N-5L1)描述平均应力松弛行为的汽轮机轮盘榫槽疲劳寿命预测方法。通过与实验结果相比较,表明混合硬化本构模型能够较好地模拟脉动加载下转子轮盘材料的循环应力应变响应及平均应力松弛行为,由此建立的寿命预测方法可对轮盘榫槽进行较为准确的疲劳寿命预测(与试验寿命误差总体落在1.5倍分散带以内),明显优于基于平均应力松弛经验公式的疲劳寿命预测值。     

铅-钡-铝磷酸盐玻璃的热性质和红外光谱

用差热分析和热机械分析研究了一种新发展的铅-钡-铝磷酸盐玻璃的热性质,表明这种玻璃的熔化温度低,转变温度和软化温度也较低,热膨胀系数大．这种玻璃的红外光谱的特点：在近红外区有一很弱的水分吸收带,在中红外区没有P＝0特征吸收带,在远红外区的三个吸收带,指示玻璃中三种金属阳离子在它们的氧笼中的振动．     

基于排队分析的端到端路径可用带宽的测量

端到端路径可用带宽是衡量网络性能的重要指标.目前,大多数对可用带宽测量的研究都集中在自拥塞方法上,但自拥塞方法会严重影响路径上的原有流量,因此,提出了一种基于模型的方法,将Internet视为一个具有单一服务单元且服务两种流量(探测流量和背景流量)的排队系统,通过分析探测流量离开排队系统的过程,在路径的负载与探测流量离去间隔的变异系数之间建立了对应关系,并在此基础上获得可用带宽值.与自拥塞方法相比,不会造成路径拥塞且具有较好的准确性.     

Nitrogen-Rich Rigid Polybenzimidazole With Phosphoric Acid Shows Promising Electrochemical Activity and Stability for High-Temperature Proton Exchange Membrane Fuel Cells

Polybenzimidazoles (PBIs) are the most promising binders for the catalyst layer (CL) in high-temperature proton exchange membrane fuel cells (HT-PEMFC). However, traditional commercial PBIs are not applied in binders because they do not enhance the electrochemical performance and because the related solvents are not environmentally friendly. In addition, proton transfer channels in PBIs are not investigated at the microscopic and atomic scales to date. In this study, a nitrogen-rich rigid PBI binder containing pyridine, diazofluorene, and partially grafted nitrile (PBPBI-3CN) is prepared with a functionalized structure, good thermal stability, and good solubility in an environmentally friendly solvent. A membrane electrode assembly (MEA) is fabricated with the PBPBI-3CN binder, providing a high peak power density, low resistance, and good stability. The protonation, hydrogen bond networks, and platform for proton transfer are confirmed in the CLs. The protonation of PBPBI-3CN occurs in two steps. First, some phosphoric acid (PA) molecules bind to nitrogen-containing acidophilic groups via preliminary protonation; second, multiple PA molecules then interact with nitrogen-containing acidophilic groups via further protonation. With protonation as the foundation, a sufficient amount of PA molecules form a hydrogen bond network, and proton transfer channels are established.     

基于SNMP进行数据挖掘的入侵检测系统研究

网络攻击日益隐蔽化和复杂化,传统入侵检测方法对此有很大局限性,该文提出将入侵检测系统和SNMP网络管理系统相结合,根据攻击的本质特征,使用数据挖掘技术从SNMP的网络统计数据中获取检测规则的方法,能有效实现对隐蔽和复杂攻击的检测。     

Effect of Preparation Methods and Condition of Precursors on the Phase Composition of Yttria-Stabilized Zirconia Powders

An yttria-stabilized zirconia powder, free of monoclinic phase, may be prepared by an oxalate method in an ethanol solution at strong acidity. This study demonstrates that the control of pH in the preparation of precursors has a significant effect on the ability of precursors to crystallize and hence plays an important role in determining the formation and fraction of various crystalline phases in the resulting yttria-stabilized zirconia powder. With the increase of pH, a precursor with a certain crystalline form may be transformed into an amorphous precursor, and a monoclinic phase appers in the phase composition of the resulting powder. The results of XRD analysis and Raman spectroscopy are discussed.     

高含水油田优势流场识别调整研究

针对砂岩油田高含水后期油层优势流场严重发育,制约水驱采收率进一步提高的难题,应用层次分析与模糊综合评价结合数值模拟方法,确定了油藏平面各优势流场影响因素的权重大小,得到了小层平面流场的模糊综合评价值及不同强度流场区域的油水井对分布状况。对优势流场区水井减注、调层及补孔治理,对弱流场区欠注水井增注调整。应用该方法对V油田某区块小层平面的优势流场判断,其中优势流场区井对7个,强优势流场区井对5个。对存在于优势流场区中的12个井组进行水井减注、封堵调层、补孔、油井合理配产、封堵等工艺。对部分欠注水井增注调整,全区综合含水率下降了1.1%,累积增产原油2.2×104 t,取得了较好的高含水期剩余油挖潜效果。     

聚氨酯制品发展概况

聚氨酯是世界六大合成材料之一，具有许多优异特性。介绍了国内外聚氨酯工业的历史与现状，简述了聚氨酯制品的原料与助剂及其主要品种的发展概况。