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91.
布里奇曼法生长碲镉汞晶体的固液界面形态研究 总被引:2,自引:0,他引:2
文中综述了布里奇曼法及加速坩埚旋转技术的布里奇曼法生工碲镉汞晶体过程中固液界面形态的研究结果,简单讨论了固液界面形态对组分分布的影响,并将两种技术所得的组分分布结果进行了比较,在分析影响固液界面形态因素的基础上,认为加速坩埚旋转技术是目前改善固液界面形态的有效方法。 相似文献
92.
塑料薄膜透气测试装置及测试方法研究 总被引:2,自引:1,他引:1
根据塑料薄膜透气原理,设计了一种简易薄膜透气测试装置,并对测试方法及结果处理进行了探讨。 相似文献
93.
本文介绍红外热象技术在工程热物理研究中某些应用的探索。作为实例,通过热象技术,实验研究了具有水平凸台离散热源的倾斜板的散热,在研究它的自然对流换热部份结合利用激光全息干涉技术。此间着重于分析倾斜角对散热的影响。 相似文献
94.
This paper presents an efficient method which provides the optimal generation mix and the optimal generation construction process. The approximation method in which the dynamic programming technique and gradient method are combined is applied to determine the optimal generation mix with hydropower generation technologies. The successive approximations dynamic programming (SADP) technique, which is very suitable for high-dimensional multistage decision process problems, is used for obtaining the optimal generation construction process. The effectiveness and feasibility of the developed technique are demonstrated on a practical power system model which has five types of generation technologies including a hydropower generation technology. 相似文献
95.
Study of direct and indirect naphtha recycling to a resid FCC unit for maximum propylene production 总被引:2,自引:0,他引:2
To satisfy the increasing propylene demand, direct and indirect naphtha recycling schemes around an existing resid fluid catalytic cracking (FCC) unit were investigated. To this aim, light cracked naphtha (LCN), heavy cracked naphtha (HCN) and a PolyNaphtha (PN) oligomerisation product were cracked under a wide range of operating conditions over a commercial Y zeolite based equilibrium catalyst. Experimental data were acquired in three different units: a fixed bed bench scale unit, a fixed fluidised bed unit and an adiabatic circulating fluidised bed pilot plant. It was shown that FCC naphthas require high operating severities to crack, and that even then their conversion remains relatively moderate. Hence, direct recycling to the main riser does not seem a viable pathway to increase propylene product. Feeding FCC naphthas to a second reaction zone operating at high severity allows to increase the propylene yield in a significant manner. Increasing conversion, however, not only leads to higher LPG and propylene yields, but also results in very high dry gas yields. An alternative scheme was proposed, in which the olefinic C4 and C5 fractions are converted into a naphtha fraction through oligomerisation in a dedicated unit before being recracked in the secondary riser. As the highly olefinic oligomerised effluent mainly consist of dimerised and trimerised butenes and pentenes, this feed is more easily cracked and high conversions can be achieved. This indirect interconversion of butenes and pentenes into propylene therefore effectively allows to convert these butenes and pentenes into propylene, resulting in a significant increase in propylene yield. Each of the three main naphtha recycle options (directly to the main riser, directly to a secondary riser or indirectly via a light olefin oligomerisation unit) have been analysed and compared to a base case. In the evaluation of each of these schemes, all heat balance effects, both on the riser and the regenerator side, have been accounted for. The proposed process scheme with an indirect recycle via an oligomerisation unit enhances the already inherent flexibility of the FCC unit. The naphtha recycle can be turned on or off, the second reaction zone can be used to crack naphtha or to crack resid feed to maximise throughput, while the effluent of the oligomerisation unit can be recycled to the FCC unit for propylene production or hydrogenated and sent to gasoline and kerosene pool. 相似文献
96.
The paper considers a generalized discrete‐time order‐replacement model for a single unit system, which is subject to random failure when in operation. Two types of discrete randomized lead times are considered for a spare unit; one is for regular (preventive) order and another is for expedited (emergency) order. The model is formulated based on the discounted cost criterion. The underlying two‐dimensional optimization problem is reduced to a simple one‐dimensional one and then the optimal ordering policy for the spare unit is characterized under two extreme conditions: (i) unlimited inventory time and (ii) zero inventory time for the spare unit. A numerical example is used to determine the optimal spare‐ordering policy numerically and to examine the sensitivity of the model parameters. 相似文献
97.
98.
热物理性质测试技术研究现状和发展趋势 总被引:3,自引:0,他引:3
本文在对热物理性质研究在热能工程、材料科学、信息科学、航天工程、环境工程、生物科学、微电子技术和计量学等众多科技领域中的重要性进行探讨的基础上,评述了热物理性质测试技术的研究现状和发展趋势。鉴于薄膜材料在微电子器件、集成电路和微电子机械系统等领域中日益广泛的应用,本文还综述了亚微米-纳米尺度薄膜材料热导率和热扩散率的测试新技术。 相似文献
99.
基于ISP技术的自动测试系统信号处理研究 总被引:5,自引:2,他引:3
在VXI总线模块及GPIB仪器构成的自动测试系统中 ,利用ispLSI10 3 2实现了测试信号的动态分配和预处理 ,有效解决了测试平台对多种复杂被测对象的适配问题。 相似文献
100.