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81.
In this paper, we present an offline arbitrated quantum blind dual-signature protocol by using four-particle entangled Greenberger-Horne-Zeilinger(GHZ) states. By using the special relationship of four-particle GHZ states, we can not only support the security of quantum signature, but also guarantee the anonymity of the message owner. In our protocol, the authority of the arbitrator has been reduced, i.e., he will not help the receiver verify the signature in the verification. Compared with the previous quantum blind signature protocols, the presented arbitrator is offline. Finally, the security analysis and discussion are proposed.  相似文献   
82.
83.
建立了中立型随机微分时滞方程的LaSalle不变原理,然后应用LaSalle不变原理讨论了不确定中立型随机时滞系统的随机渐近稳定和几乎必然指数稳定的代数判据, 同时给出示例说明结果的有效性.  相似文献   
84.
** Corresponding author. Email: longwang{at}pku.edu.cn*** Email: jizj{at}mech.pku.edu.cn In this paper, the quadratic stabilization of switched linearsystems with polytopic uncertainties is considered. Comparedwith the existing result, a more general switching control methodis proposed to guarantee the quadratic stabilization. This switchingcontrol method is based on the partition of the vertex matrixset of each subsystem. By this method, the matrix inequalitiesneeded to be solved are always less than those needed to besolved before except one extreme case; for this case, it isequal. The switched control synthesis problem is also studiedfor both switched state feedback and output feedback. Severalbilinear matrix inequality based conditions are derived forboth cases.  相似文献   
85.
Positron lifetime measurements have been performed in binary Fe3Al and Fe3Al doping with Nb or Si alloys. The densities of valence electrons of the bulk and microdefects in all tested samples have been calculated by using the positron lifetime parameters. Density of valence electron is low in the bulk of Fe3Al alloy. It indicates that, the 3d electrons in a Fe atom have strong-localized properties and tend to form covalent bonds with Al atoms, and the bonding nature in Fe3Al is a mixture of metallic and covalent bonds. The density of valence electron is very low in the defects of Fe3Al grain boundary, which makes the bonding cohesion in grain boundary quite weak. The addition of Si to Fe3Al gives rise to the decrease of the densities of valence electrons in the bulk and the grain boundary thus the metallic bonding cohesion. This makes the alloy more brittle. The addition of Nb to Fe3Al results in the decrease of the ordering energy of the alloy and increases the density of valence electron and the bonding cohesion of the grain boundary. However, since the radius of Nb atom is larger than that of Fe atom, when Nb atoms substitute for Fe atoms, they will distort the lattice and enlarge the volume of the lattice, which decreases the density of valence electron and the cohesion of metallic bond in the bulk of the alloy. Project supported by the National Natural Science Foundation of China (Grant No. 59561001) and the Foundation of Guangxi Education Committee.  相似文献   
86.
CiADS次临界反应堆采用铅铋作为冷却剂,使用绕丝定位的闭式燃料组件。螺旋绕丝能够使流动工质发生横向交混,增强不同子通道间的动量交换。本工作使用ANSYS ICEM和STAR-CCM+软件划分了结构化网格和多面体网格,对CiADS燃料棒束通道横流特性进行研究,分析了结构化网格与非结构化网格对流动特性的影响。结果显示:相比于非结构化网格,结构化网格的子通道间横流量计算结果更接近LES的结果;结构化网格得到的摩擦因子系数与UCTD公式预测值最为接近,多面体网格的结果比经验公式的预测值小。同时,本研究对现有横流特性经验公式进行了改进,可更准确地预测带绕丝燃料棒束横流特性。上述研究成果提供了子通道程序优化的新思路,同时可为CiADS燃料组件热工水力设计与分析提供参考。  相似文献   
87.
Gravitation deflects light, which has been confirmed by a large number of observation data. f(R)-gravity is modification of Einstein’s gravity. According to the field equations obtained by the action of the f(R) form, a similar Schwarzschild metric is obtained. According to the condition that four-dimension momenta of the photon return to zero and conservation of covariant momenta, we obtain an equation of photon motion in a specific form of f(R)-gravity. We solve the equation to get gravitational deflection angle of light that grazes surface of sun and the calculation result is consistent with the experimental observation data.  相似文献   
88.
The phenomena of negative mobility (NM) and multiple current reversals (MCR) are investigated numerically in an asymmetric periodic potential with a Gaussian colored noise under the influence of a periodic driving and a constant bias. Two cases have been considered: the case of noise-induced normal transport and the case of noise-induced anomalous transport. The results indicate: (1) within tailored parameter regimes, a robust and wide range of NM can be obtained for a fixed regime of correlation time; (2) nonzero correlation time can induce and diminish MCR; (3) the asymmetry can induce and significantly facilitate the anomalous transport of inertial Brownian particle.  相似文献   
89.
??In this paper, we consider a perturbed compound Poisson risk model with dependence, where the dependence structure for the claim size and the inter-claim time is modeled by a generalized Farlie-Gumbel-Morgenstern copula. The integro equations, the Laplace transforms and the defective renewal equations for the Gerber-Shiu functions are obtained. For exponential claims, some explicit expressions are obtained, and some numerical examples for the ruin probabilities are also provided.  相似文献   
90.
根据啁啾脉冲堆积的原理以及模型介绍了两路脉冲堆积时脉冲的时间与频谱特性,分析了堆积脉冲产生时间与频谱调制,以及交叠区产生非线性频率啁啾的原因。通过非线性薛定谔方程,分析了堆积脉冲的放大特性,介绍了啁啾参量对放大结果的影响以及放大后堆积脉冲的频率啁啾的变化。研究表明,在堆积脉冲的放大过程中自相位调制效应非常明显,严重影响了脉冲的频谱与频率啁啾。  相似文献   
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