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61.
颗粒尺度对纳米材料相变的影响   总被引:3,自引:0,他引:3  
运用Heisenberg模型研究了纳米材料相变的尺度效应,建立了相变与颗粒尺度之间的定量关系。模拟结果表明,这一理论与实验数据相符合。  相似文献   
62.
基于SolidWorks/COM的压铸型计算机辅助设计   总被引:5,自引:0,他引:5  
许映秋  曹伟生  王少飞 《铸造》2002,51(8):491-497
文章结合压铸型计算机辅助设计系统中标准件模块与压铸型零件注释模块的开发 ,提出并介绍了基于Solid Works/COM的应用程序开发思想与具体实现过程  相似文献   
63.
陈家能  陈华江 《铸造技术》2007,28(5):602-605
研究树脂砂的工艺特性、树脂砂使用的材料组成以及与其性能特性的关系,对树脂砂中回用砂和固化剂用量进行分析并以车用变速器为例,对树脂砂有效使用时间与强度的关系进行测定,提出了树脂砂的灼烧减量与循环再生次数的关系曲线,并阐述了变速器壳体国产化研究的铸造工艺方案和工艺参数。  相似文献   
64.
针对电液位置伺服系统存在的参数变化及外力扰动,引入模型参考模糊自适应机构,构成模型参考模糊自适应控制,即MRFAC,仿真实验表明,与传统PID相比,该方法可以有效抑制参数扰动及外力干扰,具有很强的鲁棒性。  相似文献   
65.
R.E. Melchers 《Corrosion Science》2003,45(10):2307-2323
The non-linear phenomenological model previously proposed for the ‘general’ corrosion loss of mild and low alloy steels under fully aerated ‘at-sea’ near-surface immersion conditions is applied to provide a new interpretation of literature data for copper-bearing steels. The data is examined to extract the parameters required for the model as a function of average seawater temperature. On the basis of the expectation of consistency, the data is then used to calibrate the parameters. All are generally consistent with the parameters derived earlier for mild and low alloy steels. The calibrated parameters are used to predict a consolidated plot of expected corrosion loss-time-temperature for copper-bearing steels. This compares favourably with a similar plot derived earlier from observed data alone.  相似文献   
66.
高温高压设备瞬态密封分析的三维力学与传热学模型   总被引:2,自引:0,他引:2  
以大型加氢反应器的高压法兰密封结构为研究对象,建立了瞬态及稳态密封分析的三维力学与传热学模型,主要解决了螺栓载荷的动态模拟和螺栓孔内空气环层的传热计算问题。利用该模型对加氢反应器的瞬态及稳态密封状况进行了计算。  相似文献   
67.
Testing kinetic models against a “true” and detailed kinetic expression was the aim of the Workshop on Kinetic Model Development at the Denver AIChE Meeting in August, 1983. For this purpose an artificial reaction mechanism was created, based on the known thermodynamics of the methanol synthesis as a framework. The kinetic rate laws, that were derived from this mechanism, were made thermodynamically consistent by achieving agreement between equilibrium constants calculated at various temperatures from the given, real original thermodynamic relationship and those calculated from the detailed reversible kinetic expressions.

Using the artificial kinetics as the "true" one, CSTR experiments were simulated. The results of a statistically designed set of experiments were published after 5% random error was added to the data. Participation was invited for all interested to correlate the data, develop kinetic models and to calculate the performance of the specified reactor.

The results of 19 submitted entries are summarized with the conclusion that the models had more differences than were expected, but their predictive values were not as different as was anticipated, if the extreme high production rates due to thermal runaways are not considered. This in turn points out the necessity to check models experimentally, in pilot plant, not only for predicted optimum, but also for calculated runaway conditions. Models which did not capture the true character of this reaction failed to predict the onset of runaway reactions.  相似文献   
68.
以三段七区物理模型为基础,采用面向对象程序设计语言VisualC ,对整个单螺杆挤出过程进行了数值模拟。所得压力。温度等工艺参数的模拟结果与实验值吻合较好,说明采用数学模型的正确性和数值算法的可行性。  相似文献   
69.
The disinfection effects of the ozone molecule alone and that of ozone decomposition products when inactivating Giardia muris cysts were investigated at bench-scale using two different ozone demand-free laboratory buffer systems. The first water was a 0.05 M phosphate buffer with hydrogen peroxide added at a 10:1 weight ratio. The second water was a 0.05 M phosphate – 0.01 M bicarbonate buffer which quickly scavenged radical species from ozone decomposition. The C3H/HeN mouse model was used to assess the infectivity of ozone treated cysts.

The phosphate-bicarbonate buffer system had significantly greater (P ≤ 0.05) inactivation of G. muris cysts than that observed in the phosphate buffer – peroxide system where ozone was completely decomposed in less than 120 s. Consequently, the design of ozone disinfection processes should maintain ozone residual for disinfection prior to the addition of hydrogen peroxide for the oxidation of other compounds.  相似文献   

70.
Microporous hollow fiber gas-liquid membrane contactors have a fixed and well-defined gas-liquid interfacial area. The liquid flow through the hollow fiber is laminar, thus the liquid side hydrodynamics are well known. This allows the accurate calculation of the fiber side physical mass transfer coefficient from first principles. Moreover, in the case of gas-liquid membrane contactor, the gas-liquid exposure time can be varied easily and independently without disturbing the gas-liquid interfacial area. These features of the hollow fiber membrane contactor make it very suitable as a gas-liquid model contactor and offer numerous advantages over the conventional model contactors. The applicability and the limitations of this novel model contactor for the determination of physico-chemical properties of non-reactive and reactive gas-liquid systems are investigated in the present work. Absorption of CO2 into water and into aqueous NaOH solutions are chosen as model systems to determine the physico-chemical properties for non-reactive and reactive conditions, respectively. The experimental findings for these systems show that a hollow fiber membrane contactor can be used successfully as a model contactor for the determination of various gas-liquid physico-chemical properties. Moreover, since the membrane contactor facilitates indirect contact between the two phases, the application of hollow fiber model contactor can possibly be extended to liquid-liquid systems and/or heterogeneous catalyzed gas-liquid systems.  相似文献   
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