影响调节阀安装效果因素分析及对策

调节阀的安装是调节阀寿命周期中非常重要的环节,必须充分重视调节阀的现场安装.本文从调节阀控制原理,就影响调节阀安装效果进行分析;梳理、评估调节阀安装过程中的各个关键环节,对调节阀安装进行量化,提出了提升调节阀安装效果的策略,保证调节阀平稳、可靠运行,并降低维护成本.     

调节阀流量调节理论研究

对调节阀固有阻力特性进行了分析，推导出调节阀固有阻力关系式，提出了衡量调节阀阻力的特征阻力概念，对调节阀安装特性进行了分析，得到调节阀流量调节方程式。依调节阀的结构特点将调节阀的开度划分为有效行程区、无效行程区和强调区三个区域。提出了界点的定义，得到在安装状态下，调节阀界点下移的结论。     

天然气场站流量调节阀技术改造分析及应用

在天然气场站日常生产输气过程中利用流量调节阀对管道天然气进行流量控制，可以有效地完成下游用户企业的气量调配，保护相关的分输设备，并在一定程度上缓解峰谷差给天然气场站带来的压力。但在流量调节阀的选型上，轴流式与曲流式流量调节阀在日常生产实际中却表现出一定的差异。现根据湖北省天然气发展有限公司仙人渡接收站已完成的将场站部分曲流式流量调节阀更换为四川长仪的流量调节阀技术改造，列举了轴流型调节阀与曲流式调节阀的区别与联系，分别分析了轴流式调节阀与曲流式流量调节阀特点。     

水下呼吸器用调节阀的设计改进

为降低水下呼吸器用调节阀的吸气阻力,在充分分析调节阀工作原理和吸气阻力形成机理的基础上,对原有调节阀的阀芯结构进行了设计改进。并对新型调节阀进行了受力分析研究,建立了调节阀的吸气阻力求解模型。理论计算和试验研究表明：新型调节阀的吸气阻力由1321 Pa降低为806 Pa,大大提高了调节阀的使用性能;吸气阻力理论计算值和实际测试值的误差在合理范围内,新型调节阀的吸气阻力求解模型可为其结构设计和参数优化提供一定的理论基础。     

调节阀的选型及维护

以气动薄膜调节阀为例,简要介绍了调节阀的工作原理,详细论述了调节阀选型的原则及方法,并就调节阀的维护事项及方法作了简单的说明。     

调节阀的选择与安装

介绍了通过选择调节阀的类型、口径和流量特性以达到正确选择调节阀的目的,以及如何正确安装调节阀。     

关于核级气动调节阀填料密封的讨论

研究了调节阀填料的密封机理,比较了国内外核级气动调节阀的填料密封测试标准,讨论了核级调节阀的填料密封力对填料密封能力、填料使用寿命、调节阀静态和动态调节性能、以及调节阀抗震性能的影响。     

单座调节阀耐水冲击数学模型

在调节阀中,介质的流速以冲击力的形式对阀内件产生很大的损伤。经过分析单座调节阀的工作状态,把单座调节阀的工作状态简化为孔板节流过程。通过使用动量方程、伯努利方程和连续性方程建立单座调节阀耐水冲击的数学模型,得到不同开度下,单座调节阀所受到的冲击力。     

基于CFD的迷宫式调节阀内流场分析

建立了迷宫式调节阀内流场的二分之一几何模型,应用计算流体力学(CFD)的方法对迷宫式调节阀的内流场进行数值模拟,计算得到了在不同开度时迷宫式调节阀整体的流量系数和阀芯各个盘片的流量系数,分析了迷宫式调节阀内局部流场的流动特性,为迷宫式调节阀的相关研发工作提供参考。     

调节阀执行机构研究

调节阀是物料或能量供给系统中不可缺少的重要组成部分,而执行机构是调节阀的关键组成部件.针对执行机构对调节阀工作性能的影响,分析了调节阀的执行机构类型,讨论了不同类型执行机构的组成、工作原理和特点,在此基础上对不同类型的执行机构适用范围进行了探讨,为调节阀的选择提供指导作用.     

Histochemical and ultrahistochemical localization of heavy metals in calf organs

Cadmium, zinc, selenium, and copper were administered, singly or in combination, orally or subcutaneously. Experiment I included 32 calves of both sexes; six received Cd (two groups), Zn, Cd, and Zn, and Cd and Se (two groups) and one group was a control. In Experiment II (21 bulls), three were given Cd, Cd, and Cu, and Cd and Zn, respectively, and one group was a control. For light microscopy, in Experiment I the highest amounts of silver granules were present in the samples of liver, small intestine, and vesicular gland of all the exposed groups; in Experiment II the most affected organs were liver, kidney, and small intestine. For electron microscopy, in Experiment I, after administration of Cd and Zn, the highest amounts of granules were seen in the cytoplasm of hepatocytes and cells of the proximal and distal renal tubules and the lowest amounts were found in glandular cells of the pancreas. Administration of Cd and Se resulted in the presence of large numbers of granules in the nuclei and nucleoli of spermatogonies. In Experiment II, ingestion of Cd and Zn in feed led to the appearance of highest amounts of granules in the nucleoli, nuclei, and cytoplasm of cells in testes, kidneys, and pancreas. Following Cd intake, the highest accumulation of granules was observed in the nucleoli of hepatocytes and cells of the proximal and distal renal tubules. Combined Cd and Cu produced the highest number of granules in cells of the proximal and distal renal tubules and in the nucleoli and nuclei of germinal epithelium.     

DESIGN AND ANALYSIS OF NOVEL ACTIVE ACTUATOR TO CONTROL LOW FREQUENCY VIBRATIONS OF SHAFT SYSTEM

Aiming at providing with high-load capability in active vibration control of large-scale rotor system, a new type of active actuator to simultaneously reduce the dangers of low frequency flexural and torsional vibrations is designed. The actuator employs electro-hydraulic system and can provide a high and circumferential load. To initialize new research, the characteristics of various kinds of active actuators to control rotor shaft vibration are briefly introduced. The purpose of this paper is to introduce the preliminary results via presenting the structure, functions and operating principles, in particular, the working process of the electro-hydraulic system of the new actuator which includes a set of high speed electromagnetic valves and a series of sloping cone-shaped openings, and presenting the transmission relationships among the control parameters from control signals into the valves to active load onto shaft. The course of the work is dynamic, and a series of spatial forces and moments are put on the shaft to get an external resultant force to reduce excitations that induce vibration of shafts. By checking states of vibration, the actuator can control the impulse width and the interval of injection time for applying different control force to a vibration shaft in two circumference directions through the regulating action of a set of combination directional control valves. The results from simulating analysis and experiment show evidence of that this design can satisfy the case of active process of decreasing of flexural and torsional vibrations.     

气化炉三维扫描测量与数据处理

以德士古气化炉耐火砖的内壁蚀损检测设备为基础,对采集到的点云数据做了进一步处理.通过对数据的筛选和剔除,实现了数据点的平滑降噪细化和精简.然后利用点云对整、网格划分和分色显示等方法,最终完成了内壁腐蚀情况的三维建模.重点讨论了点云数据的预处理及后处理的方法,并根据内壁耐火砖的腐蚀阈值,提出了一种气化炉内壁腐蚀区域的识别与分割方法.对耐火砖的腐蚀分析、气化炉的生产与维修提供了可靠依据,并在工程应用中获得了一致认可.     

软体足式机器人驱动、建模与仿真研究综述

软体足式机器人因其优越的移动性能及面对复杂地形的通过能力受到越来越多研究者的关注。由于受到材料性质、驱动方法及制造工艺等多方面的限制,如何实现软体足式机器人的创新结构设计,提升软体机器人的运动速度和负载能力是目前亟待解决的问题之一。综述从仿生结构与驱动方法的角度对目前软体足式机器人的研究发展进行了系统阐述。由于软体机器人多为连续变形结构,加之软材料的物理非线性和软结构变形的几何非线性,力学建模与仿真一直是软体机器人研究领域的瓶颈。梳理了目前软体机器人的主要建模理论,总结了软体机械臂的建模与控制方法,进一步将其拓展到软体足式机器人的系统建模中。介绍了传统商业软件的应用与物理仿真引擎开发的进展,分析了软体机器人虚拟仿真的主要方法,展望了软体足式机器人的应用场景与未来研究方向。     

缩口扩口复合成型工艺研究与应用

针对铁路车辆罐车零件锥管缩口、扩口的成型特点,用冲压成型缩口、扩口的力学分析及变形原理进行工艺计算与研究,找出该零件废品率高的原因。通过改进工艺毛坯（钢管）的外径与壁厚尺寸,用冲压成型缩口、扩口工艺理论及图表进行论证分析,并进行试制,取得了较好的效果。     

Mass spectrometry analysis of the influenza virus

The role of mass spectrometry to probe characteristics of the influenza virus, and vaccine and antiviral drugs that target the virus, are reviewed. Genetic and proteomic approaches have been applied which incorporate high resolution mass spectrometry and mass mapping to genotype the virus and establish its evolution in terms of the primary structure of the surface protein antigens. A mass spectrometric immunoassay has been developed and applied to assess the structure and antigenicity of the virus in terms of the hemagglutinin antigen. The quantitation of the hemagglutinin antigen in vaccine preparations has also been conducted that is of importance to their efficacy. Finally, the characterization and quantitation of antiviral drugs against the virus, and their metabolites, have been monitored in blood, serum, and urine. The combined approaches demonstrate the strengths of modern mass spectrometric methods for the characterization of this killer virus. [This article was published online 10 September 2008. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 7 November 2008.]     

增压器涡轮叶片疲劳蠕变寿命预测方法

根据径流式增压器涡轮的结构与工作特点,分析了涡轮叶片的载荷与应力空间分布特征;针对增压器涡轮由疲劳与蠕变交互作用引起的叶根断裂失效模式,研究了增压器涡轮叶片叶根的载荷与应力变化历程,建立了涡轮叶片叶根的载荷与应力描述方法;然后建立了增压器涡轮叶片叶根疲劳蠕变寿命预测方法及模型,并运用建立的模型对增压器涡轮叶片叶根进行了寿命评估。     

二维运动平台气浮静压导轨承载性能计算与研究

为了进一步探索和研究气浮静压润滑支承机理及气浮静压导轨承载性能,提出并研制了一种具有气浮静压润滑支承的精密二维运动平台。结合气浮静压导轨的物理模型建立了其笛卡儿坐标系下的控制方程,采用有限差分方法和流量平衡原理对其控制方程进行了离散差分推导,运用超松弛迭代以及二分快速寻找收敛区间法对其承载性能进行数值计算并开展了实验研究。结果表明：气浮静压导轨承载性能受节流器类型的影响比较显著,多节流孔节流器的承载性能明显优于单节流孔节流器;供气压力对气浮静压导轨承载性能影响显著,供气压力越高其承载性能越强;同等条件下气浮静压导轨组合形式承载性能均优于单独形式承载性能;气浮静压导轨的承载性能实验测试结果和数值计算结果具有较好的一致性,验证了数值计算的有效性。相关研究对推动和促进气浮静压轴承和导轨在精密运动机构和测量设备的研究和工程应用具有较好的借鉴和指导意义。     

基于刚柔耦合的高方平筛动力学建模与振动模态分析

针对高方平筛和其上固结的柔性吊杆组成的动力学系统,进行了刚柔耦合的动力学建模和振动模态分析。将筛体—偏重块系统和吊杆分别作为刚体和弹性的可变形体,建立了筛体稳态圆振动方程和吊杆悬臂梁力学模型,总结出系统固有频率的计算方法。在此基础上,采用有限元方法对系统进行了模态计算和动力学响应分析。结果表明,理论模型能够很好地反映筛体与吊杆之间的动力学耦合关系;以理论分析为基础的载荷和边界条件的设置,使有限元仿真结果较准确地模拟了系统实际的振动特性。     

覆膜铁熔融覆膜过程界面传热与熔膜填充行为研究

覆膜铁是金属包装领域的新型复合材料。成品覆膜铁的界面结合强度和水透性取决于覆膜过程中高聚物薄膜熔融层的厚度和流动铺展行为。但覆膜过程复杂而迅速，且受钢板表面微观形貌影响，熔融层膜厚及其流动铺展行为难以精细调控。针对此，基于分形理论表征与重构基板带钢表面微观形貌；基于广义Maxwell模型试验建立聚合物膜的黏弹性本构关系；建立了考虑基板带钢表面微观形貌的覆膜过程有限元仿真模型，并试验验证了模型的准确性。研究表明，熔融层膜厚主要受基板带钢初始预热温度影响，界面填充率则主要受覆膜辊压力影响。高聚物膜熔融层厚度和界面填充率随基板带钢粗糙度降低以及基板带钢和覆膜辊初始预热温度增加而增加，且辊压力增加也导致界面填充率增加。这些规律被定量化描述，为精细化调控熔融层膜厚及其流动铺展行为提供了理论依据。