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901.
902.
The effects of electromigration on copper in carbon nanotube (CNT) channels are investigated using molecular dynamics simulations. The study shows that the potential energy of copper and the resistive forces on copper are dependent on the shape of the CNT junction, and the increase in bias voltages magnifies these effects. Bias voltages affect the density of copper in the downstream CNT. The velocity of copper in the downstream CNT is relatively lower than that in the upstream CNT when the biased voltage is high. 相似文献
903.
This study proposes an expectation–maximization (EM)-based curve evolution algorithm for segmentation of magnetic resonance brain images. In the proposed algorithm, the evolution curve is constrained not only by a shape-based statistical model but also by a hidden variable model from image observation. The hidden variable model herein is defined by the local voxel labeling, which is unknown and estimated by the expected likelihood function derived from the image data and prior anatomical knowledge. In the M-step, the shapes of the structures are estimated jointly by encoding the hidden variable model and the statistical prior model obtained from the training stage. In the E-step, the expected observation likelihood and the prior distribution of the hidden variables are estimated. In experiments, the proposed automatic segmentation algorithm is applied to multiple gray nuclei structures such as caudate, putamens and thalamus of three-dimensional magnetic resonance imaging in volunteers and patients. As for the robustness and accuracy of the segmentation algorithm, the results of the proposed EM-joint shape-based algorithm outperformed those obtained using the statistical shape model-based techniques in the same framework and a current state-of-the-art region competition level set method. 相似文献
904.
红外光谱技术由于其灵敏度高和对样品的非破坏性等优点已成为研究生物大分子损伤的重要工具。蛋白质、脂质和核酸等受到损伤时,其红外光谱特征吸收峰的峰位、峰型和峰强会发生变化,这为检测生物大分子损伤并进一步揭示相关疾病的发生、发展及早期预防提供了依据。还综述了近年来使用红外光谱法检测生物大分子损伤的研究进展,介绍了利用傅里叶变换红外光谱、衰减全反射傅里叶变换红外光谱和傅里叶红外显微等技术在蛋白质二级结构、膜脂流动性和离子通透性以及药物对DNA的作用机制等领域的应用,以及相关的定性和定量分析方法进行了评述,提出了目前红外光谱分析技术中存在的问题,并对今后红外光谱在生物医学领域中的应用前景作了展望,指出疾病早期诊断、红外光谱联用以及定量分析技术等将成为红外光谱领域未来的研究热点。 相似文献
905.
906.
This paper is devoted to the existence and long time behavior of the global classical solution to Fokker-Planck-Boltzmann equation with initial data near the absolute Maxwellian. 相似文献
907.
提出了一种新的磨光函数,在分析它与已有磨光函数不同特性的基础上,研究了将它用于求解非线性P_0互补问题时,其磨光路径的存在性和连续性,进而设计了求解一类非线性P_0互补问题的非单调磨光算法.在适当的假设条件下,证明了该算法的全局收敛性和局部超线性收敛性.数值算例验证了算法的有效性. 相似文献
908.
This paper describes the quality of convergence to an infinitely divisible law relative to free multiplicative convolution. We show that convergence in distribution for products of identically distributed and infinitesimal free random variables implies superconvergence of their probability densities to the density of the limit law. Superconvergence to the marginal law of free multiplicative Brownian motion at a specified time is also studied. In the unitary case, the superconvergence to free Brownian motion and that to the Haar measure are shown to be uniform over the entire unit circle, implying further a free entropic limit theorem and a universality result for unitary free Lévy processes. Finally, the method of proofs on the positive half-line gives rise to a new multiplicative Boolean to free Bercovici–Pata bijection. 相似文献
909.
We consider the Cauchy problem for the incompressible Navier-Stokes equations in R 3, and provide a new regularity criterion involving only two entries of the Jacobian matrix of the velocity field. 相似文献
910.
Robust decentralized adaptive synchronization of general complex networks with coupling delayed and uncertainties
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The problem of robust decentralized adaptive synchronization of general complex networks with coupling delayed and uncertainties is investigated in this article. It is only assumed that the upper normal bound of uncertain inner and outer coupling matrices is positive but its concrete structure is not also required to be known. The time‐varying coupling delay is a any nonnegative continuous and bounded function and not require its derivative to be less than one, that is, general time‐varying coupling delays and uncertainties. For such a class of uncertain complex networks, a new synchronization scheme is presented by a class of continuous memoryless robust decentralized adaptive synchronization controllers. It is also shown that the synchronization error dynamics of uncertain complex networks can be guaranteed as uniformly exponentially convergent toward a ball that can be as small as desired. Finally, numerical simulations are provided to demonstrate the effectiveness and robustness of proposed complex networks synchronization schemes. © 2013 Wiley Periodicals, Inc. Complexity 19: 10–26, 2014 相似文献