行程相关变阻尼油压减振器的阻尼特性分析

根据行程相关变阻尼油压减振器的基本结构、工作原理和阀系特点,利用弹性力学的基本理论推导出了环形弹性阀片受均布载荷时的挠曲变形解析式,基于上述解析式在多领域系统仿真分析软件AMESim中建立了行程相关变阻尼油压减振器的仿真模型,并利用该仿真模型分析了减振器结构参数与阀系参数对阻尼特性的影响。结果表明:旁通节流槽等效节流面积对软特性区的拉伸阻尼力和压缩阻尼力都有影响,但对拉伸阻尼力的影响程度更为明显;复原阀等效厚度增加,减振器在软、硬特性区的拉伸阻尼力都增大,但对压缩阻尼力基本无影响;流通阀等效厚度增加,减振器在软、硬特性区的压缩阻尼力都增大,但对拉伸阻尼力基本无影响。     

A proteomic analysis of green and white sturgeon larvae exposed to heat stress and selenium

Temperature and selenium are two environmental parameters that potentially affect reproduction and stock recruitment of sturgeon in the San Francisco Bay/Delta Estuary. To identify proteins whose expression is modified by these environmental stressors, we performed a proteomic analysis on larval green and white sturgeons exposed to 18 or 26 °C and micro-injected with Seleno-L-Methionine to reach 8 µg g⁻¹ selenium body burden, with L-Methionine as a control. Selenium and high temperature induced mortalities and abnormal morphologies in both species, with a higher mortality in green sturgeon. Larval proteins were separated by two-dimensional gel electrophoresis and differential abundances were detected following spot quantitation and hierarchical cluster analysis. In green sturgeon, 34 of 551 protein spots detected on gels showed a variation in abundance whereas in white sturgeon only 9 of 580 protein spots were differentially expressed (P < 0.01). Gel replicates were first grouped according to heat treatment. Fifteen of these spots were identified using MALDI TOF/TOF mass spectrometry. Proteins involved in protein folding, protein synthesis, protein degradation, ATP supply and structural proteins changed in abundance in response to heat and/or selenium. 40S ribosomal protein SA, FK506-binding protein 10, 65 kDa regulatory subunit A of protein phosphatase 2, protein disulfide isomerase, stress-induced-phosphoprotein 1, suppression of tumorigenicity 13 and collagen type II alpha 1, were differentially expressed in high temperature treatment only. Serine/arginine repetitive matrix protein 1, creatine kinase, serine peptidase inhibitor Kazal type 5 and HSP90 were sensitive to combined temperature and selenium exposure. Valosin-containing protein, a protein involved in aggresome formation and in protein quality control decreased more than 50% in response to selenium treatment. Potential use of such proteins as biomarkers of environmental stressors in larval sturgeons could indicate early warning signals preceding population decline.     

冷凝机组供热改造中汽轮机内效率的提高

纯冷凝机组进行热电联产改造时对大焓降缩放喷嘴进行改型设计，可减少因调节级后压力升高而产生的激波损失，但这种改造方法不能完全消除激波现象。针对汽机低真空供暖及打孔抽汽改造，本文分析提出不同的改造的方案，不但可以完全消除激波，且能保证汽机大部分压力级仍在原设计的参数附近运行，提高汽机总内效率，使热电联产改造获得最佳经济效益。     

限流BaTiO3陶瓷PTCR元件化学沉积欧姆电极的研究

本文对程控交换机用过流保护ＢａＴｉＯ３陶瓷ＰＴＣＲ元件不同化学沉积镍和铜电极的耐工频电流冲击性能和稳定性进行了比较研究，对所得结果进行了充分的讨论。     

高压电缆缓冲层烧蚀缺陷的超声检测实验

高压电缆缓冲层烧蚀故障是近年来频发的电缆故障类型，然而目前的烧蚀缺陷检测手段难以满足存量电缆的检测需求。本文首次研究了基于铝护套内表面粗糙度的高压电缆缓冲层烧蚀缺陷的超声检测方法。首先，开展了潮湿条件下的缓冲层烧蚀模拟实验，并对烧蚀后的铝片开展了激光共聚焦显微镜测试以及电化学阻抗谱分析，发现随着烧蚀时间的增加，铝片的表面粗糙度逐渐增大，同时铝片表面的腐蚀程度逐渐加深，对应的缓冲层烧蚀缺陷逐渐加重，表明铝片的表面粗糙度与潮湿条件下缓冲层的烧蚀程度存在关联。其次，对烧蚀后的铝片开展了超声检测实验，并通过相邻超声回波信号的幅值比推算出了铝片腐蚀面的粗糙度，与实验测得的粗糙度具有相同的变化趋势。本文结果表明超声检测可用于检测缓冲层烧蚀缺陷的严重程度，为高压电缆缓冲层烧蚀缺陷超声检测方法的应用奠定了研究基础。     

减振器振动系统稳定性分析与研究

该文在建立振动动力学模型和运动方程的基础上 ,通过对车辆悬架阻尼比分析 ,就减振器阻尼等效为零或为负时 ,对振动系统稳定性影响及产生原因进行了探讨 .提出设计和制造过程中有效控制系统稳定和非保守特性的技术路线     

Performance of non-destructive evaluation by diffracted SH ultrasonic waves in predicting degree of fatigue in cyclic bending of ferritic steel

The degree of fatigue in ferritic wrought steel during cyclic bending was determined by analysis of diffracted SH ultrasonic waves with the aid of multiple regression analysis. As the degree of fatigue increases, accompanied by residual stress, the incident waves curve to the interior region with positive stress field owing to the acoustoelastic effect. As a result, the propagation time of the launched waves lengthens, leading to a modulation of the received waveform. Multiple regression analysis for the waveform modulation produces a reliable estimation, with correlation coefficient of 0.948, for the degree of fatigue.     

火炮点火药的冲击波点火现象研究

本文研究了口径火炮点火药的冲击波点火。利用轻气炮作为冲击波加载设备，利用激光速度步步仪和锰铜压阻法作为测量手段和方法，研究了ＨＹ－５和硼／硝酸两种点火药在冲击波作用下界面的雨贡组参数，还得到了两种点火的临界冲波压力近似值。     

减振器行星旋压封口工艺及设备

该文根据工艺原理和试验研究基础 ,将行星旋压工艺应用于减振器封口 .文中分析和介绍了减振器行星旋压封口技术的工艺参数和工艺设备     

工程陶瓷小孔超声振动钻削的理论探讨

通过对超声振动钻削的运动学分析 ,推导了临界钻削速度的计算公式 ,并分析了超声振动钻削提高孔径质量的机理。