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给出了随机变量变换分布的三个推论,这些推论提供了在不同变换下求二维随机变量的函数的概率密度的计算公式,实例应用表明,这些公式应用简便,灵活,实用. 相似文献
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The pulsed thermographic technique was used to detect flat-bottomed hole defects in SiC coated high-temperature alloy plates. Temperature–time Logarithm Fitting Method (TtLFM), Principal Component Analysis (PCA) and Pulsed Phase Thermography (PPT) were used to extract the characteristic information of the thermal wave signal generated by thermal pulse. It is found that PCA algorithm is available for analyzing the thermal wave signal generated by thermal pulse due to higher signal–noise ratio. Experiments were performed to investigate the effect on the thermal contrast by the pulse intensity, frame rate and analysis moment, respectively. Experimental results show that larger pulse intensity and frame rate are benefit to get larger thermal contrast thermogram, and optimal analysis moment selected is helpful to detect the defects of SiC coated high-temperature alloy plates using pulsed thermographic technique. 相似文献
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在大学物理课程铁磁质知识点的教学中,结合工程实践教育,使讲授的知识点能够理论联系实际,在提高教学效果的同时,使学生认识到理论知识在工程实践中的应用,进而使学生树立正确的知识价值观,提高学习兴趣,增强主动学习的意识. 相似文献
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An approach for solving Fredholm integral equations of the first kind is proposed for in a reproducing kernel Hilbert space (RKHS). The interest in this problem is strongly motivated by applications to actual prospecting. In many applications one is puzzled by an ill-posed problem in space C[a,b] or L2[a,b], namely, measurements of the experimental data can result in unbounded errors of solutions of the equation. In this work, the representation of solutions for Fredholm integral equations of the first kind is obtained if there are solutions and the stability of solutions is discussed in RKHS. At the same time, a conclusion is obtained that approximate solutions are also stable with respect to ∞ or L2 in RKHS. A numerical experiment shows that the method given in the work is valid. 相似文献
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Yongfang Zhou Minggen Cui Yingzhen Lin 《Journal of Computational and Applied Mathematics》2009,230(2):770-780
The parabolic problems with non-classical conditions are discussed in a reproducing kernel space in this paper. A reproducing kernel space is constructed, in which the non-classical conditions of the parabolic problems are satisfied. Based on the reproducing kernel space, a new technique for solving the non-classical parabolic problems is presented. Some examples are displayed to demonstrate the validity and applicability of the proposed method. 相似文献
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Considered is a Yoffe crack in an infinite strip of functionally grated material (FGM) subjected to antiplane shear. The shear moduli in two directions of FGM are assumed to be of exponential form. The dynamic stress intensity factor and strain energy density factor at the crack tip are obtained by using integral transforms and dual-integral equations. The numerical results show that the decrease of the strain energy density factor varies with the shear moduli gradient, and the increase of the strain energy density factor varies with the increase of the moving crack speed. The ratio of shear moduli in material vertical orientation has a great influence on the strain energy density factor. 相似文献
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该文研究如下的弱奇异边值问题: (p(x)y')'=f(x, y),0b0g(x), 0≤b0<1, 边值条件为y(0)=A,αy(1)+β y'(1)=γ 或y'(0)=0,αy(1)+βy'(1)=γ (R.K.Pandey 和 Arvind K.Singh 给出了一种求解此问题的二阶有限差分方法[1]. 在再生核空间中讨论方程解的存在性, 给出一种新的迭代算法,这种迭代算法是大范围收敛的. 给出数值算例并与R. K. Pandey 和Arvind K.Singh 给出的方法进行比较说明该文方法的有效性. 相似文献