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91.
J. Mirkovic Y. Kubo T. Saitou I. Kakeya T. Yamamoto A. Oral K. Kadowaki 《Physica C: Superconductivity and its Applications》2009,469(15-20):1119-1121
The c-axis resistivity measurements were performed in the vicinity of the ab-plane in order to investigate the interaction between Josephson vortices and pancake vortices in Bi2Sr2CaCu2O8+δ mesoscopic single crystals. It was found that the angular dependence of the c-axis resistivity drastically changes in high magnetic field regime. The vortex lock-in transition becomes considerably broad in high magnetic fields, while the angular dependence of resistance exhibits the sharp lock-in features in low magnetic field region. 相似文献
92.
Wenbo Hu Tingchao He Hui Zhao Haojie Tao Runfeng Chen Lu Jin Junzi Li Quli Fan Wei Huang Alexander Baev Paras N. Prasad 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(32):11222-11228
Photosensitizers (PSs) with stimuli‐responsive reversible switching of intersystem crossing (ISC) are highly promising for smart photodynamic therapy (PDT), but achieving this goal remains a tremendous challenge. This study introduces a strategy to obtain such reversible switching of ISC in a new class of PSs, which exhibit stimuli‐initiated twisting of conjugated backbone. We present a multidisciplinary approach that includes femtosecond transient absorption spectroscopy and quantum chemical calculations. The organic structures reported show remarkably enhanced ISC efficiency (ΦISC), switching from nearly 0 to 90 %, through an increase in the degree of twisting, providing an innovative mechanism to promote ISC. This leads us to propose here and demonstrate the concept of smart PDT, where pH‐induced reversible twisting maximizes the ISC rate, and thus enables strong photodynamic action only under pathological stimulus (such as change in pH, hypoxia, or exposure to enzymes). The ISC process is turned off to deactivate PDT ability, when the PS is transferred or metabolized away from pathological region. 相似文献
93.
优化网络结构以促进信息在网络中传播一直是复杂网络研究的重点,网络中边的聚类特性和扩散特性对信息传播具有重要作用. K-truss分解算法是一种利用边的聚类特性识别网络关键节点的算法,然而K-truss算法会受到网络中局部聚类结果 (即相互连接的假核结构)的影响,而这些假核结构里的节点对信息扩散能力通常较弱.为此,本文提出一种衡量边扩散特性的指标,研究发现一些位于网络边缘的边具有很好的扩散性,但这类边的聚类很低,并不利于信息传播.通过同时考虑边的聚类特性和扩散特性之间的制约关系,提出一种信息传播网络结构优化算法.为了验证所提算法的有效性,使用该算法对四个真实的网络进行结构优化,并使用经典的独立级联模型来验证网络结构优化前后信息传播的有效范围.结果表明:使用提出的算法优化后的网络拓扑可以有效提高信息传播范围;并且,优化后的网络其叶子节点数目降低、聚类系数降低以及平均路径长度降低. 相似文献
94.
95.
交叉隧道施工中新建隧道周围复合地层与间距对既有隧道的沉降影响研究 总被引:2,自引:0,他引:2
沿海地区特别是广州地区地铁建设多在复合地层中进行盾构施工,开挖引起的地层沉降很难控制,如何防止大面积的地层沉降,保证既有建(构)物安全成为施工难题。基于此,本文提出了复合地层盾构施工的地质概化模型,运用三维有限元方法对交叉隧道盾构施工进行了建模分析,研究了不同的复合地层类型及不同的覆土厚度与间距下,新建隧道盾构正交下穿施工对既有隧道沉降的影响。结果表明,新建隧道在近似均一土层中下穿施工引起的既有隧道沉降最大,上软下硬地层次之,长距离硬岩段最小,沉降随土层弹性模量的增加而减小; 同时,既有隧道沉降随覆土厚度的增加而增大; 随隧道间距的增大而减小,当间距小于2倍衬砌外径时,既有隧道沉降较大,存在损坏的危险。最后,提出了相应的沉降控制对策。 相似文献
96.
Camera calibration from vanishing points in a vision system 总被引:1,自引:0,他引:1
Camera calibration has been studied for many years and there are many methods available to find the parameters precisely. However, most existing methods require information of the known scene points in general three-dimensional positions for the calibration. A simple, geometrically intuitive method is proposed. The intrinsic parameters of the camera are determined by using the vanishing points in each image. The rotation matrix of the projection matrix is computed from the vanishing and image edges and the translation matrix are obtained with additional translation motion between the viewpoints. Our approach does not need any a priori information about the cameras being used. Computer simulations and real data experiments are carried out to validate our method. 相似文献
97.
The paper examines the use of expressions proposed by Csanady to predict the influence of the crossing trajectory and continuity effects on the decorrelation time scales of the fluid along solid particle trajectories in horizontal and downward vertical channel flows. The model is evaluated using data provided by a direct numerical simulation (DNS) of the carrier phase combined with a Lagrangian simulation of discrete particle (LS). Two particle relaxation times and two values of the gravity acceleration are considered. The results show the possibility of using Csanady’s expressions in a turbulent channel flow provided that the spatial and temporal correlations anisotropy is included in the model. As in isotropic homogeneous turbulence, a decrease of the decorrelation time scales is found to be more important in the directions perpendicular to the mean relative velocity. 相似文献
98.
Robert C. Brigham Julie R. Carrington Ronald D. Dutton Joseph Fiedler Richard P. Vitray 《Journal of Graph Theory》2000,35(4):278-289
This paper discusses the problem of finding the maximum number of edges E(m, n, B) in a bipartite graph having partite set sizes m and n and bandwidth B. Exact values for E(m, n, B) are found for many cases. © 2000 John Wiley & Sons, Inc. J Graph Theory 35: 278–289, 2000 相似文献
99.
The spatial shapes of magnetoelastic shear body waves at the transmission edges in a periodically inhomogeneous magnetostrictive
medium are studied. Numerical results are obtained for a two-component composition of ferrite and nonmagnetic dielectric
__________
Translated from Prikladnaya Mekhanika, Vol. 42, No. 3, pp. 61–69, March 2006. 相似文献
100.
This research is aimed at studing the effect of ionizing radiation in an heterogeneous system formed by a carboxylic acid adsorbed in a clay mineral. The study is focussed to discriminate if the presence of a solid surface alters the formation and distribution of radiolytic products in relation to the radiolysis of the carboxylic acid without the surface (clay). The results showed that the radiolysis of the system clay-acid goes along a defined path rather than showing various pathways of decomposition as in the case of simple aqueous solutions. The main pathway was the decarboxylation of the target compound rather than condensation/dimerization reactions. 相似文献