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11.
Kosuke Kurokawa 《Electrical Engineering in Japan》1993,113(4):54-65
Solar radiation has an irregularly varying factor due to a basic day and night cycle and climatic conditions. For such conditions a data sampling interval is important to ensure the accuracy of energy monitoring in a photovoltaic system. While treating a system monitoring equipment as a black box. the author has developed the method of calibrating an energy-integrating function. At first for various input waveforms, the relationship between sampling intervals and quasi-integration outputs have been examined by trapezoidal rule. In the numerical simulation the phases of the sampling clock also are considered Then it is concluded that a sampling interval can be inspected through outside observation only by using a rectangular single pulse. By applying the pulse to the energy-integrating process, two kinds of integrated outputs can be obtained for different sampling phases. The calculated difference between both outputs can uniquely give the sampling interval being inspected. Conditions to ensure measuring accuracy are discussed and the validity of this method has been demonstrated experimentally. Practical calibrating procedures also are proposed for the integrating function of PV system monitoring. 相似文献
12.
针对铝电解原材料中AlF3与Al2O3自动配料不准和难于观察及控制的现象,我厂开发应用了AlF3贮仓料位计,并与微机网络相连,实现了远程测量与在线监控,使AlF3配料更准确更均匀,电解质分子比更稳定,电解槽生产低耗高效。 相似文献
13.
通过对安庆石化总厂化肥厂CO_2压缩机多起强烈振动信号的频谱分析,找出了谱图上的一些规律性特征,并在理论上加以解释,文章还提出了现场应急处理的对策以及根治办法。 相似文献
14.
Xylose fermentation by Pichia stipitis was examined using a two-stage batch process. The cells were first grown aerobically on D-xylose (5 g/L), whereafter additional xylose (10 g/L) was added and fermented during anaerobic conditions (T=30°C). The optimum pH value for a fermentation with constant pH was found to be 4.5 (maximum specific ethanol production rate 0.21 g/(g h). Forced square wave cycling of the pH between 4 and 5, and 3.5 and 5.5 (cycle time 30 min) during the fermentation stage resulted in a fermentation rate lower than the maximum rate, but with unchanged ethanol yields. 相似文献
15.
Heat capacities at constant pressure, Cp, and at constant volume Cv, were calculated with the help of normal mode frequency spectra and compared to experimental data for crystalline or semicrystalline polyethylene, poly(vinyl fluoride), poly(vinylidene fluoride), polytrifluooroethylene and poly(tetrafluoroethylene). A calculation scheme using a Tarasov function for 2N skeletal vibrational modes and an approximation of the residual 7N normal modes from known data on polyethylene and polytetrafluoroethylene is developed for all homologous, linear fluoropolymers. N is the number of carbon backbone atoms of the repeating unit. Calculations can be carried out over the whole temperature range 0 K to melting. For the two theta temperatures and the constant A0 used for Cv to Cp conversion, fluorine-concentration dependent curves are given. The relations are expected to hold also for copolymers and blends of intermediate fluorine contents. Recommended experimental (data bank) heat capacities agree to ±2.5% with the calculations. 相似文献
16.
近年来,高职院校都比较注重特色专业的建设。其中,特色专业建设的监控体系也受到了高职院校的重视,并取得了一定的效果,同时,也给其他院校提供了有价值的参考和借鉴。但由于在认识水平、管理水平和教学水平等方面仍有一些问题,导致在监控过程和措施实施方面还存在许多疏漏,有待完善。 相似文献
17.
资源监控是网格计算的关键组成部分。资源监控算法既要保证网格系统中资源信息高保真度又要考虑资源信息在网络传输中的负担最低。ACTC算法就是为实现以上目的而被提出,但是算法中对资源信息更新量的动态门槛值(d_threshold)计算方式不合理,有可能导致算法演变成低级的单纯依靠时间敏感机制(TSM)来发送资源更新通知,并且算法中遗漏了一些极端情况的考虑。提出了新的d_threshold计算公式和限制条件,进行性能改进和完善,并对改进前后两算法进行实验对比。实验表明,改进后算法提高了资源信息准确性,并使监控系统 相似文献
18.
K8型单层球面网壳支座减震 总被引:1,自引:0,他引:1
于志伟 《哈尔滨工业大学学报》2009,41(4):7-11
为了对跨度为60 m的K8型单层球面网壳进行了减震分析,分别将结构的支座设置成弹性支座和弹性阻尼支座,对结构进行减震控制.结合对结构在有控和无控状态下自振特性的分析,阐述了单层球面网壳结构的减震控制原理.在常遇地震作用下,得到网壳结构的最大水平位移、减震支座的最大水平位移、最大支座反力和最大杆件内力.通过改变支座的刚度和阻尼系数,对两种减震方案的减震效果进行比较.研究结果表明:两种减震装置均有效地控制了K8型单层球面网壳结构的支座反力,弹性阻尼支座还可以明显地降低减震支座的水平位移. 相似文献
19.
To evaluate the wear condition of machines accurately,oil spectrographic entropy,mutual information and ICA analysis methods based on information theory are presented. A full-scale diagnosis utilizing all channels of spectrographic analysis can be obtained. By measuring the complexity and correlativity,the characteristics of wear condition of machines can be shown clearly. The diagnostic quality is improved. The analysis processes of these monitoring methods are given through the explanation of examples. The availability of these methods is validated and further research fields are demonstrated. 相似文献
20.
LEI Peng CHANG XiaoLin XIAO Feng ZHANG GuiJin & SU HuaiZhi School of Hydraulic Engineering Changsha University of Science Technology Changsha China College of Water Resources Hydroelectric Engineering Wuhan University.Wuhan Mid-south Design Research Institute China Hydropower Engineering Consulting Group Co Changsha College of Water Conservancy Hydropower Engineering Hohai University Nanjing 《中国科学:信息科学(英文版)》2011,(6)
Owing to the deficiency in early warning for high concrete dam,a formula was established to characterize the deformation behavior of high concrete dam as a whole.The early warning index of spatial deformation was calculated by low probability principle on the basis of the deformation entropy formula proposed.The steps were as follows.Firstly,the probability method was utilized to define the degree of order and degree of chaos for each survey point.Secondly,the weight distribution among the survey points was... 相似文献