罐头封口理论及方法

本文从力学、材料学、成形理论多方面论述了金属罐头的封口原理与方法。从应用角度分析了封口机构的工作特点及应注意的问题。并对未来技术进行了预测与展望。     

铁岭500kV系统取消断路器合闸电阻的过电压计算

计算了铁岭500kV系统中5条线路在不同年代、不同接线、不同运行方式下的工频过电压、潜供电流以及仅用不同型号MOA限制这些线路的合闸及重合闸(单重)过电压.     

论我国股市道德的"蛛网理论"

当前我国股市正在快速发展中,股市道德问题也日益为世人瞩目。股市道德及不道德力量同股市欺诈等问题具有相互对应关系,这就形成了一个制衡机制;在具体的运行中,其制衡机制可以两种依道德曲线的斜率不同,而呈封闭、收敛和发散三种"蛛网"运行状态;依此原理,以德治市的关键是要遏制"发散的蛛网"、争取股市运行于"收敛的蛛网"状态。     

基于有限元的汽轮发电机模型机设计研究

研究与300MW大型汽轮发电机同槽数的7.5kW模型机和300MW发电机的空载特性相似性。运用FEM(有限元)稳态计算程序计算模型机的空载特性,将计算数据与试验数据进行对比验证程序的可靠性。选定、转子铁心具有恒定高导磁率时所得空载线为反映气隙磁压降的实际气隙线,并以二者气隙线重合为基准对空载曲线作标么值处理,电压基值选各自电机额定端电压,电流基值选气隙线上各自达到额定电压时对应的励磁电流,从而在同一张图中对比两电机的实际饱和特性与气隙线的靠近程度。通过改变模型机转子导磁材料、气隙大小,得出结论:在允许范围内选用高导磁性材料、加大气隙可以改善模型机和300MW发电机的空载特性相似性。讨论了材料饱和程度与空载饱和特性相似性的关系。     

A finite-element model for the study of vibration of a beam with a closing crack

We present a finite-element model to be used in a study of vibration of a beam with a closing crack. Some special features of numerical solution and methods for its fast realization are discussed. The results of experimental verification of the model are provided. __________ Translated from Problemy Prochnosti, No. 5, pp. 114–120, September–October, 2008.     

浅谈安康医院的特点与设计

结合新疆兵团公安安康医院综合病房大楼的设计,对安康医院与精神病医院进行了对比,总结了安康医院及使用者的特点,从安全性、封闭性、特殊性等方面,深入探讨了安康医院的设计,可供同行参考。     

带直联主变压器的水轮发电机磁能估算

提出了一种带直联主变压器的水轮发电机磁场能量的估算方法，给出了发电机-主变压器组联合空载特性的概念，并利用发电机空载特性的分析表达式和主变压器空载磁化曲线的折线表达式进行了Simulink仿真。最后，针对三峡700MW水轮发电机组进行了带直联主变压器的水轮发电机磁场能量估算。     

高压喷射灌浆在木头滩围堰施工的试验

分析了防城港市木头滩引水工程坝址的工程地质情况,介绍了用高压喷射灌浆进行围堰基础堵漏试验的场地选择、钻孔布置、设备选型及施工工艺流程,分析评价了试验成果。     

澳大利亚GPA 5000t/h装船机除尘系统设计

散货码头设备在转运物料过程中,难免产生扬尘,对环境造成污染。为了最大限度减少灰尘,澳大利亚装船机上采用了干式除尘、喷淋除尘、封闭控尘等一系列的防尘措施,取得了良好的抑尘效果。     

Liquid penetration length of heptamethylnonane and trimethylpentane under unsteady in-cylinder conditions

While strategies employing early or late direct-injection of fuel can improve emissions, they also can lead to impingement of liquid-phase fuel on the piston and/or cylinder wall due to low in-cylinder temperatures and densities during the injection event. Previous work has shown that liquid-phase fuel films formed in this way can lead to pronounced degradations in efficiency and emissions. To avoid these problems, a quantitative understanding of fuel-property effects on the liquid penetration length is needed, and this understanding must include conditions where in-cylinder thermodynamic conditions and the injection rate vary with time. This work reports liquid penetration lengths measured in an optical engine under such time-varying conditions. Diagnostics included laser light scattering for measurement of the liquid length and conventional pressure-data acquisition for heat-release analysis. Unsteady liquid penetration was characterized for different injection timings, injection pressures, intake-manifold pressures, and fuel volatilities to gain an understanding of the relative importance of these factors. Fuel volatility was studied by using two fuels, 2,2,4,4,6,8,8-heptamethylnonane (HMN) and 2,2,4-trimethylpentane (TMP), which have very different volatility characteristics. Measured liquid lengths changed as in-cylinder conditions changed, with increasing temperature and density during the compression stroke causing a decrease in liquid length, and decreasing temperature and density during the expansion stroke causing an increase in liquid length. Intake-manifold pressure and fuel volatility were found to be primary factors governing liquid length. Heat loss from the charge gas to the engine and local charge cooling due to fuel vaporization were found to have a secondary influence on liquid length. Injection pressure was found to have little effect.