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991.
Giovanna Guidoboni Roland Glowinski Nicola Cavallini Suncica Canic 《Journal of computational physics》2009,228(18):6916-6937
We introduce a novel loosely coupled-type algorithm for fluid–structure interaction between blood flow and thin vascular walls. This algorithm successfully deals with the difficulties associated with the “added mass effect”, which is known to be the cause of numerical instabilities in fluid–structure interaction problems involving fluid and structure of comparable densities. Our algorithm is based on a time-discretization via operator splitting which is applied, in a novel way, to separate the fluid sub-problem from the structure elastodynamics sub-problem. In contrast with traditional loosely-coupled schemes, no iterations are necessary between the fluid and structure sub-problems; this is due to the fact that our novel splitting strategy uses the “added mass effect” to stabilize rather than to destabilize the numerical algorithm. This stabilizing effect is obtained by employing the kinematic lateral boundary condition to establish a tight link between the velocities of the fluid and of the structure in each sub-problem. The stability of the scheme is discussed on a simplified benchmark problem and we use energy arguments to show that the proposed scheme is unconditionally stable. Due to the crucial role played by the kinematic lateral boundary condition, the proposed algorithm is named the “kinematically coupled scheme”. 相似文献
992.
Qiang Li 《International Journal of Theoretical Physics》2009,48(5):1508-1515
Motivated by the fermions tunneling formalism of Kerner and Mann, we attempt to investigate quantum tunneling of Dirac particles
from a five dimensions double Myers-Perry black hole, which describes the superposition of two Myers-Perry black holes, each
with a single angular momentum parameter and both in the same plane. After introducing several appropriate Gamma matrixes
for the covariant Dirac equation, we obtain the tunneling probability of Dirac particles from the double Myers-Perry black
hole, which gives the expected emission temperature as the case of scalar particles that obtained by others. 相似文献
993.
Xue-qin Zuo Yi-min Liu Zi-yun Zhang Zhan-jun Zhang 《International Journal of Theoretical Physics》2009,48(7):1950-1956
We propose a tripartite scheme for bisplitting an arbitrary single-qubit quantum information (QI) by using a class of asymmetric
three-qubit W state as quantum channels. In the scheme, the sender Alice first performs a Bell-state measurement on her two
qubits and then publishes her measurement result via a public classical channel. Based on Alice’s message, if the two receivers
Bob and Charlie collaborate together, they can retrieve the QI, i.e., they can deterministically recover the QI in one receiver’s
site by first performing a two-qubit unitary operation and then executing a single-qubit unitary operation. Afterwards, we
sketch the extension of the single-qubit QI splitting to an arbitrary N-qubit QI splitting. 相似文献
994.
Focal depth and focal splitting of hyperbolic-cosine-Gaussian beams induced by a phase plate were investigated. The pure phase plate consists of three concentric zones: a center circle zone, an inner annular zone and an outer annular zone. The phase variance of the inner annular zone is adjustable. Simulation results show that the focal depth can be adjusted by changing the radii of zones. With the increase of the inner radius of the outer annular zone, the focal spot broadens along the optical axis and splits into two peaks. Then the two peaks combine back into one peak. There are two critical values for the inner radius of the outer annular zone, at which focal spot changes sharply. The tunable range of the focal depth varies considerably. The phase variance of the inner annular zone affects focal depth also; when the phase variance is π, the effect attains maximum. The parameters of cosh parts of the beam affect both focal splitting and focal depth evidently; focal splitting disappears with increasing parameters of cosh parts, and focal depth increases with increasing the parameters of cosh parts in both the low and the high numerical-aperture optical systems. 相似文献
995.
光子数分束攻击对星地量子密钥分配系统安全的影响 总被引:2,自引:1,他引:1
由于仪器设备性能的不完美和信道传输损耗的存在,光子数分束(PNS)攻击对采用弱相干脉冲(WCP)光源的量子密钥分配(QKD)系统的安全性构成重大威胁.以基于WCP光源的星地QKD系统为研究对象,推导了在PNS攻击者采用最佳窃听策略进行窃听时,保证密钥绝对安全的最大天顶角和可采用的平均光子数之间的关系.理论分析和计算结果表明,星地QKD系统的最大安全传输天顶角和可使用的平均光子数等重要系统参数的取值上限均受PNS攻击的限制,最终系统的密钥交换速率和系统容量受到限制.对星地QKD系统的传输容量来说,天顶角和平均光子数是一对矛盾的影响因素.提供了一种对实际星地QKD系统的天顶角和平均光子数参数进行估算的方法. 相似文献
996.
997.
998.
利用共线快离子束-激光光谱学方法测量了钕离子所有7个稳定同位素(A=142~146,148,150)之间的同位素位移和两个奇同位素(A=143,145)的超精细结构分裂. 相似文献
999.
1000.
Hidehisa Hagiwara Dr. Takanori Inoue Prof. Dr. Kenji Kaneko Prof. Dr. Tatsumi Ishihara Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(46):12862-12870
The mechanism of photocatalytic splitting of H2O into H2 and O2 on Pt/KTa(Zr)O3 modified with various porphyrinoids was investigated. The photocatalytic activity of KTaO3 catalysts is improved by dye modification. Cyanocobalamin (vitamin B12) is the most effective for improving water‐splitting activity, and the formation rates of H2 and O2 achieved values of 575 and 280 μmol gcat.?1 h?1, respectively. X‐ray photoelectron spectroscopy spectra of KTa(Zr)O3 photocatalysts showed that Pt loaded onto dye‐modified KTaO3 was slightly oxidized and had low catalytic activity for the H2 oxidation reaction. Photoluminescence (PL) spectra of KTaO3 catalysts suggested that excitation energy was transferred between KTaO3, tetraphenylporphyrinatochromium(III) (Cr–TPP), and the Pt cocatalyst. The wavelength dependence of the activity of dye‐modified KTa(Zr)O3 photocatalysts indicated that excitation of both KTa(Zr)O3 and the dye was essential for achieving increased photocatalytic activity. This result suggests that two‐step excitation occurred in the dye‐modified KTa(Zr)O3 photocatalysts. Because the lifetime of the charge‐separated state increased, this study reveals that modification with porphyrinoids is effective for increasing water‐splitting activity. 相似文献