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排序方式: 共有127条查询结果,搜索用时 125 毫秒
41.
L. E. Reichl 《Journal of statistical physics》1980,23(1):83-110
This is the first of two papers in which microscopic expressions for the amplitudes and dispersion relations for hydrodynamic modes in an isotropic Fermi superfluid are derived. In this first paper we derive closed, decoupled, linearized kinetic equations for the bogolon spin density and total density in a Fermi superfluid with fluctuating superfluid velocity, and we discuss the form of the hydrodynamic equations that result from these equations. 相似文献
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É. I. Starovoitov D. V. Leonenko A. V. Yarovaya 《International Applied Mechanics》2003,39(12):1458-1463
The paper studies axisymmetric resonance vibrations of an elastic circular sandwich plate under local periodic surface loads of rectangular, sinusoidal, and parabolic forms. The hypotheses of broken normal are used to describe the kinematics of the plate, which is asymmetric in thickness. The core is assumed to be light. The initial–boundary-value problems are solved analytically. The solutions are analyzed 相似文献
44.
We proposed and numerically investigated the influence of spatial topology on the infrared frequency region response of chiral metamaterials based on discrete deformed split ring resonators. Compared with the well studied continuous helix, the proposed metamaterials with discrete topology exhibit broad band chiral electromagnetic response. It is shown that the conversion between left and right circular polarization waves for our model is much broader than the continuous helix model. The observed cross-coupling between electric and magnetic fields results from the chiral electric currents on the resonators due to the broken mirror symmetry. The findings are useful for the design of future real three-dimensional chiral metamaterials with tunable optical response. 相似文献
45.
The two-gluonic decay modes ofW andZ in the broken colour model with integrally charged quarks are considered. The gluonic branching ratios are found to be 3%
and 2·7% forW andZ respectively. The angular distributions of the decays ofW andZ to two jets of hadrons are also worked out. 相似文献
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由于低维材料表面上的单原子和分子具有丰富的物理化学性质,现已经成为量子器件及催化科学等领域的研究热点.单层硅烯在不同的衬底制备温度下,表现出丰富的超结构,这些超结构为实现有序的单原子或分子吸附提供了可靠的模板.利用原位硅烯薄膜制备,分子沉积,超高真空扫描隧道显微镜以及扫描隧道谱,本文研究了Ag(111)衬底上3种硅烯超结构((4×4),(■×■),(2■×2■))的电子态结构,表面功函数随超结构的变化,以及CoPc分子在这3种超结构硅烯上的吸附行为.研究结果表明,这3种超结构的硅烯具有类似的电子能带结构,且存在电子从Ag(111)衬底转移到硅烯上的可能性,从而导致硅烯的表面功函数增大,表面功函数在原子级尺度上的变化对分子的选择性吸附起着重要作用.此外,还观察到分子与硅烯的相互作用导致CoPc分子的电子结构发生对称性破缺. 相似文献
49.
ANALYSIS OF SHIP MANEUVERING PERFORMANCES AND ICE LOADS ON SHIP HULL WITH DISCRETE ELEMENT MODEL IN BROKEN-ICE FIELDS 总被引:1,自引:0,他引:1
采用离散元模型对碎冰区浮冰与船舶结构的相互作用进行了数值研究。碎冰由三维圆盘单元构成,并考虑其在海流作用下的浮力、拖曳力和附加质量。船体结构由一系列三角形单元组合构造。通过海冰与船体单元间的接触判断和接触力计算,确定海冰与船体结构之间的相互作用。采用以上离散单元模型对不同冰况(冰速、冰厚、冰块尺寸和密集度)以及航速条件下,海冰对船体的动力作用过程进行了数值分析,对比分析了以上因素对船体冰载荷的影响,可为冰区船舶的安全运行和结构设计提供一定的借鉴作用。 相似文献
50.
《International journal of quantum chemistry》2018,118(15)
The enzyme nitrogenase contains a complicated MoFe7CS9 cofactor with 35 possible broken‐symmetry (BS) states. We have studied how the energies of these states depend on the geometry, the surrounding protein, the DFT functional and the basis set, studying the resting state, a one‐electron reduced state and a protonated state. We find that the effect of the basis set is small, up to 11 kJ/mol. Likewise, the effect of the surrounding protein is restricted, up to 10 and 7 kJ/mol for the electrostatic and van der Waals energy terms. Single‐point energies calculated on a single geometry give a good correlation (R2 = 0.92‐0.98) to energies calculated after geometry optimization, but some BS states may be disfavored by up to 37 kJ/mol. A change from the pure TPSS functional to the hybrid B3LYP functional may change the relative energies by up to 58 kJ/mol and the correlation between the two results is only 0.57‐0.72. Both functionals agree that BS7 is the most stable BS state and that the ground spin state is the quartet for the resting state and the quintet for the reduced state. With the TPSS functional, the BS6 state is the second most stable state, always at least 21 kJ/mol less stable than the BS7 state. However, with the B3LYP functional, BS10 is the second most stable state and for the protonated state it comes close in energy. Based on these results, we suggest a procedure how to consider the 35 BS states in future investigations of the nitrogenase reaction mechanism. 相似文献