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71.
72.
利用模糊评判方法确定张东构造油藏储量计算的可靠程度 总被引:1,自引:0,他引:1
张巨河油田张东构造地处大港滩海交接处,海域部分探井少.目前用油藏描述方法计算的探明储量,其落实程度备受关注.储量落实程度的评价是一个多因素综合评判问题,而且这些因素还分属不同层次.模糊综合评判是应用较为广泛的模糊数学方法之一.该方法建立的综合评判涉及三个要素,即因素集、评判集和单因素评判,由此所构造的模糊评判关系是模糊综合评判的基础.本文用该方法对张东构造沙二段油藏的探明储量落实程度作了尝试性评价. 相似文献
73.
74.
The PTC-type BaTiO3 ceramics of similar microstructure are obtained by careful control of a sintering scheme. The defect chemistry of them is modified by varying the cooling rate and annealing conditons. In addition to applying Heywang and Jonker models for explaining the resistivity anomaly of these samples, the outward diffusion of oxygen vacancies (VO), which left excess barium vacancies (VBa) behind, is proposed to be the formation mechanism of surface states. The formation of defect complex consisting of a V
O
..
-
Ba
pair is assumed to be the cause of small diffusivity of VO in these materials. The phenomena, in which the slower cooling rate raises the resistivity of samples, is ascribed to the higher concentration of excess barium vacancies (VBa) contained in these samples. However, the maximum potential barrier height (max) of the samples is the same, irrespective of the amount of surface state concentration (N
s) and is estimated to be max = 0.66eV, from the In (max)-1/T
max plot. 相似文献
75.
In the fed-batch cultivation of Saccharomyces cerevisiae, excessive glucose addition leads to increased ethanol accumulation, which will reduce the efficiency of glucose utilization and inhibit product synthesis. Insufficient glucose addition limits cell growth. To properly regulate glucose feed, a different evolution algorithm based on self-adaptive control strategy was proposed, consisting of three modules (PID, system identification and parameter optimization). Performance of the proposed and conventional PID controllers was validated and compared in simulated and experimental cultivations. In the simulation, cultivation with the self-adaptive control strategy had a more stable glucose feed rate and concentration, more stable ethanol concentration around the set-point (1.0 g•L-1), and final biomass concentration of 34.5 g-DCW•L-1, 29.2% higher than that with a conventional PID control strategy. In the experiment, the cultivation with the self-adaptive control strategy also had more stable glucose and ethanol concentrations, as well as a final biomass concentration that was 37.4% higher than that using the conventional strategy. 相似文献
76.
PKI技术及其在校园网中的应用研究 总被引:1,自引:0,他引:1
将PKI技术引入校园网络,构建基于PKI技术的数字认证中心,既保证了校园网络的安全性,实现安全文件传输,又解决了校园网络用户身份认证的问题,推进高校信息化的同时提高校园网的安全性。 相似文献
77.
An important direction of metamodeling research focuses on developing methods which can iteratively improve the accuracy of
the metamodel. The intention of these kinds of strategies is to use a space reduction strategy to lead response surface refinement
to a smaller design space; and new sample points are commonly generated near the optimum. The potential risk is that some
characteristics of given problems might be lost, especially for nonlinear problems. Therefore, a novel metamodel-assisted
optimization called “Min–Median–Max” (M3) is proposed. This algorithm classifies sample points into three categories (maximum,
median and minimum) based on corresponding objective function values, new sample points should be generated by considering
combination of three kinds of samples. In order to avoid local convergence and control size of sample points, particle swarm
optimization (PSO) algorithm and radial basis function (RBF) metamodeling technique are integrated to implement the suggested
M3 strategy. To validate the performance of the M3 strategy, multiple mathematical test functions are used for evaluating
the accuracy and efficiency. As a practical engineering application, drawbead design of a stamping system is optimized. The
results demonstrate applicability and effectiveness of the M3 algorithm. 相似文献
78.
本文给出的有理分式反Z变换方法可以同时给出因果和逆因果两种序列.由于它避免了现有三种反Z变换方法所必需的确定分式极点的困难及误差,所以使用起来较为方便和精确.它可用来研究子波信号的延迟性质与系统(如滤波器)稳定性和可逆性,还可用来求解线性系统的差分方程,确定分式零点与极点的定位范围. 相似文献
79.
80.