排序方式: 共有74条查询结果,搜索用时 15 毫秒
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以新基本放大器为基础 ,在推导出各单环放大器的计算公式的前提下 ,推导出了双环交叉负反馈放大电路分析计算的通用公式 相似文献
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楼建华 《兵团教育学院学报》2009,19(1):45-47
讨论了方程x^k=x^k-1+x^k-2+……+x+1的性质根,并利用其给出了k阶Fibonacci数列的通项公式及其性质,最后,给出了该数列的一些算法,并对这些算法做了简要分析。 相似文献
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Statistical analysis of exponential lifetimes under an adaptive Type‐II progressive censoring scheme
In this article, a mixture of Type‐I censoring and Type‐II progressive censoring schemes, called an adaptive Type‐II progressive censoring scheme, is introduced for life testing or reliability experiments. For this censoring scheme, the effective sample size m is fixed in advance, and the progressive censoring scheme is provided but the number of items progressively removed from the experiment upon failure may change during the experiment. If the experimental time exceeds a prefixed time T but the number of observed failures does not reach m, we terminate the experiment as soon as possible by adjusting the number of items progressively removed from the experiment upon failure. Computational formulae for the expected total test time are provided. Point and interval estimation of the failure rate for exponentially distributed failure times are discussed for this censoring scheme. The various methods are compared using Monte Carlo simulation. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 相似文献
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《防务技术》2020,16(4):910-921
Non-cylindrical casings filled with explosives have undergone rapid development in warhead design and explosion control. The fragment spatial distribution of prismatic casings is more complex than that of traditional cylindrical casings. In this study, numerical and experimental investigations into the fragment spatial distribution of a prismatic casing were conducted. A new numerical method, which adds the Lagrangian marker points to the Eulerian grid, was proposed to track the multi-material interfaces and material dynamic fractures. Physical quantity mappings between the Lagrangian marker points and Eulerian grid were achieved by their topological relationship. Thereafter, the fragment spatial distributions of the prismatic casing with different fragment sizes, fragment shapes, and casing geometries were obtained using the numerical method. Moreover, fragment spatial distribution experiments were conducted on the prismatic casing with different fragment sizes and shapes, and the experimental data were compared with the numerical results. The effects of the fragment and casing geometry on the fragment spatial distributions were determined by analyzing the numerical results and experimental data. Finally, a formula including the casing geometry parameters was fitted to predict the fragment spatial distribution of the prismatic casing under internal explosive loading. 相似文献
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Yongbo Xiao 《海军后勤学研究》2018,65(1):3-25
In many applications, managers face the problem of replenishing and selling products during a finite time horizon. We investigate the problem of making dynamic and joint decisions on product replenishment and selling in order to improve profit. We consider a backlog scenario in which penalty cost (resulting from fulfillment delay) and accommodation cost (resulting from shortage at the end of the selling horizon) are incurred. Based on continuous‐time and discrete‐state dynamic programming, we study the optimal joint decisions and characterize their structural properties. We establish an upper bound for the optimal expected profit and develop a fluid policy by resorting to the deterministic version of the problem (ie, the fluid problem). The fluid policy is shown to be asymptotically optimal for the original stochastic problem when the problem size is sufficiently large. The static nature of the fluid policy and its lack of flexibility in matching supply with demand motivate us to develop a “target‐inventory” heuristic, which is shown, numerically, to be a significant improvement over the fluid policy. Scenarios with discrete feasible sets and lost‐sales are also discussed in this article. 相似文献
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计算声自导鱼雷直进射击成功概率的解析方法 总被引:1,自引:0,他引:1
为解决用仿真方法计算声自导鱼雷直进射击成功概率速度慢且计算的等概率线不光滑等问题,利用数学分析及概率统计的理论,给出了一个计算目标能进入直进射击的声自导鱼雷自导作用扇面概率的近似解析公式,并用仿真方法对这个公式进行了评价,数值实验发现,所得公式能满足一定的精度要求. 相似文献
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考虑细观结构变化的原状Q3黄土变形和强度特性 总被引:1,自引:0,他引:1
为研究结构性对非饱和原状Q3黄土变形和强度特性的影响,做了12个非饱和原状Q3黄土的CT-三轴侧向卸荷试验。在试验剪切过程中,利用CT机对试样进行跟踪扫描,共得到168张CT图像。基于试验数据建立了细观结构参数,并利用该参数来反映非饱和原状Q3黄土的变形和强度特性,从而得到能反映细观结构性影响的非线性应力-应变关系以及摩尔-库伦强度公式。 相似文献
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价层电子对互斥理论在推测分子构型方面有着广泛的应用,是现代分子结构理论的一个重要知识点,通过简洁的数学推导证明了分子构型与价层电子对之间的对应关系,并根据解析几何学分析多面体各顶点与其中心的距离,借以判断多原子分子中中心原子的孤对电子应处的位置,其结论完全符合价层电子对互斥理论的预测。 相似文献
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