排序方式： 共有140条查询结果，搜索用时 203 毫秒
61.
目的 研究了具有阻尼项和高阶Laplace算子的非线性双曲型偏微分方程解的振动性.方法 应用积分平均技术和Riccati变换方法.结果或结论 获得了该方程在所给边值条件下所有解振动的一些新的充分条件. 相似文献
62.
运算电路的解析,常用部分因式展开法进行拉普拉斯反变换,以求取时城解。对象函数分母进行因式分解,可能出现复根情况的讨论,相关课程、文献分析不够深入,给出的求取原函数方法单一,解题容易出错。为此,对复根情况进行了较为深入的探讨,并提出了一种新颖的求解原函数的方法,消除了求解高阶象函数的原函数困惑,并很大提高了求取原函数的速度和准确率。 相似文献
63.
本文研究了Vandermonde行列式的推广形式,给出了这类广义Vandermonde行列式满足的一些性质,并利用Laplace展开定理给出了这类行列式的计算公式。 相似文献
64.
Ibrahim Kocabas 《Journal of The Franklin Institute》2011,348(7):1339-1362
The Laplace transformation technique has been widely applied to modeling of tracer transport in oil and geothermal reservoirs, and in groundwater aquifers. However, mathematical models of many flow and transport problems could only be obtained as Laplace space solutions, and hence, their computations had to involve a numerical inversion technique.In this work, we employ the iterated Laplace transformation technique to develop novel closed form solutions to the tracer transport models in heterogeneous media. Two types of configurations have been considered: tracer transport in single fracture located in low-permeability matrix and tracer transport in a double porosity medium consisting of flowing and dead-end pore systems. In addition, both linear and radial flow geometries have been considered for both configurations. Applications of iterated Laplace transform technique to these four types of models are presented as fundamental examples and their numerical results were used as benchmarking for the numerical inversion results from Stehfest and Dubner and Abate algorithms.As the technique is quite versatile, we expect that the method should gain widespread acceptance to develop solutions to a wide range of problems in flow and transport in porous media and improve the application of nonlinear regression technique to these solutions.This work has achieved four important objectives: first, two novel Laplace transform relations that are useful in tracer studies are presented. Second, the present work serves to verify/invalidate the results of numerical inversion algorithms. In addition, it provides better insight into tracer transport mechanisms. Finally, it serves as a powerful tool of design and interpretation of tracer tests. All four objectives are illustrated in this work. 相似文献
65.
滞回比较器是一种多用途的比较器,本文中选择它来控制Buck电路。利用滞回比较器的滞回特性控制Buck电路的输出在一个很小的范围内变化,从而保证了系统具有很高的稳定性。对受滞回比较器控制的Buck电路而言,其输出的求解方法有状态空间法、微分方程法以及拉普拉斯变换法等。本文所提出的算法是基于状态空间法的,并在其基础上引入一种等价无穷小的概念,从而化简了转移矩阵,避免了由于直接利用状态空间法解方程而带来的不便。通过Matlab编程以及PSPICE仿真,都有力地验证了本解法的有效性和正确性。 相似文献
66.
用似然比的概念研究非负的连续性的随机变量序列的极限性质,得到一类与其条件期望的随机偏差定理,在证明中提出了将Laplace变换这个工具应用到极限研究的一种途径。 相似文献
67.
随着新世纪我国社会转型,我国必然实现从传统体育体制到现代体育体制的转型,并重构我国现代体育大厦.在可供选择的诸种模式中,以为新型举国体制是可行的,这种新型体制不仅能充分发挥政府的主导作用,更能充分发挥社会和市场的能动性,从而实现国家任务和大众体育利益和谐统一的共同目标. 相似文献
68.
Wang Junsheng 《东南大学学报》1996,(1)
ＶａｒｉｏｕｓＧｒｏｗｔｈＰａｔｅｒｎｓａｎｄＭｏｒｐｈｏｌｏｇｙＴｒａｎｓｉｔｉｏｎｓｏｆＭｅｔａｌｌｅａｖｅｓＷａｎｇＪｕｎｓｈｅｎｇ（王俊生）（１．ＮａｔｉｏｎａｌＬａｂｏｆＭｏｌｅｃｕｌａｒａｎｄＢｉｏｍｏｌｅｃｕｌａｒＥｌｅｃｔｒｏｎｉｃ... 相似文献
69.
通过讨论Laplace算子的正交变换形式不变性,证明了在正交变换条件下,不同区域之间有形如Green公式的关系.作为这个结论的一个特殊情形,指出并证明了在旋转正交变换之下,推广以后的Green公式在形式上也具有不变性. 相似文献
70.
韩宝燕 《临沂师范学院学报》2005,27(6):11-13
运用倒向随机微分方程的初值解给出了对一给定的适应于布朗运动信息流的随机过程的随机 Laplace变换的定义,给出并证明其性质,最后给出两个例子．并指出经典Laplace变换是本文的特例． 相似文献