S型波纹管纯弯曲应力和位移的研究

本文引用圆环壳弯曲方程一般解.计算了有实用价值的S型波纹管纯弯曲应力和位移。着重研究了与波纹管设计及应用有关的最主要参数,即最大应力和刚度随S型波纹管初相角变化情况。     

双螺旋弹簧质量系统动态响应分析

许多工程结构应用了双螺旋弹簧质量系统(如炮闩的复进簧),这种系统的非线性动态响应分析的解法国内外尚属罕见;本文分析计算了在纵向冲击载荷作用下,双螺旋弹簧质量系统中的动态应力变化规律及其最大值;理论计算结果与实验符合良好.这种方法可用来进行双螺旋弹簧质量系统的动态强度设计计算.     

坝内钢管强度设计的问题及改进

坝内钢管在水电站中应用广泛,但现行的设计理论和方法一般偏于保守,更难于适应大容量、高水头电站的发展,本文根据理论分析和试验研究,提出了改进坝内钢管强度设计的具体措施和方向,对工程设计和进一步开展科学研究,具有实际意义。     

酸洗成膜中凝汽器管快速失效的原因分析及对策

对某300 MW火电厂机组凝汽器在化学清洗成膜过程中发生的不锈钢管大规模快速失效的过程、特征等进行了详细介绍,通过化学元素分析、金相分析、模拟试验等相关的试验研究,得出结论:酸洗液进入不锈钢管内只会对管子产生轻度损伤或是产生管子损伤的诱导因素,而硫酸亚铁成膜液进入不锈钢管内才是导致管子短时间内失效的真正原因。     

锅炉“四管”爆漏原因分析及对策

对神头第一发电厂捷制锅炉“四管”爆漏的原因进行了分析 ,针对造成爆漏的主要原因提出了相应的对策     

MS型摄像管聚焦磁场的计算

对磁聚焦静电偏转型(MS型)摄像管的聚焦磁场进行了分析,模拟计算了聚焦磁场的大小,给出了磁聚焦电子轨迹的计算方法及计算结果,并对所得结果进行分析。文中计算公式对于计算机辅助设计摄像管聚焦磁场是适用和方便的。     

塞曼效应原子吸收光谱法直接测定环境水质中痕量铅镉铜锰铁锌

本文研究了各种石墨管的实际应用,提出采用各元素合适的石墨管,用石墨炉和火焰AA.s能直接测定天然环境水和饮用水中痕量Pb Cd Cu Mn Fe和Zn的分析方法。测定检出限为Pb1.5,Cu.2.58,Mn 0.82,Cd 0.055,Fe 17.7,Zn 6.3的PPb。对监控标准水样的测定RSD是0.94～8.06%。应用于监控标准水样中痕量元素的测定其结果与已知值相符,满足天然环境水和饮用水质标准的分析要求。     

Elastic properties of natural rubber tubes produced by dip‐coating

The mechanical properties of rubber tubes produced by dip‐coating technique and the influence of the fabrication process on their structural properties were evaluated. Cyclic tension versus deformation tests were performed to investigate the elastic properties of the samples and to understand the changes in rubber tubes behavior under repetitive stress. The effect of the wall thickness on the elastic response of the tubes was also studied. The mechanical properties of opened tubes were also investigated for transversal and longitudinal directions to evaluate the influence of the fabrication process on the alignment of the polymer chains. This investigation indicated that the fabricated tubes are resistant and extremely elastic. They can be elongated up to 800% of its initial length before rupture, and thicker tubes are a bit more resistant to elongation than the thinner ones. In addition, the fabricated tubes have an anisotropic structure due to the fabrication process. Finally, natural rubber tubes may have a great potential to be used as vascular prosthesis, or in other applications that require a large range of resistance and elasticity. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 702–707, 2006     

Subjective reactions to misconvergence on a colour display

Subjective ratings of various degrees of misconvergence were obtained from subjects viewing text and graphics pictures on a 355 mm high-resolution shadow mask colour CRT display. The pictures were displayed in four secondary colours: white, yellow, turquoise (cyan), and pink (magenta). In commercial applications, user acceptance and satisfaction often present more stringent requirements for front-of-screen quality than do objective performance criteria such as legibility. In this case, it is expected that the picture quality would become unacceptable at lower levels of misconvergence than would cause it to be considered illegible. The results show a marked degradation in apparent quality of convergence as misconvergence increases from about 0.2 mm to about 0.5 mm. To obtain subjectively acceptable picture quality, misconvergence should be no more than about 0.3 mm and should be better than 0.2 mm over the majority of the screen. (The spot size of the display used was about 0.8 mm.) Textual and graphical pictures did not produce significantly different results.     

多孔介质材料在低温下的传热特性实验研究

对多孔介质材料在低温下的传热特性进行了实验研究,在填充液氮以后其低温维持时间明显增加,主要原因是由于多孔材料的参与改变了传热特性;采用连续介质管束模型,用有限元分析软件对其整体温度场分布进行了数值模拟计算,计算结果和实验数据吻合。