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Plasma technology has widespread applications in many fields, whereas the methods for manipulating plasma transport are limited to magnetic control. In this study, we used a simplified diffusion-migration approach to describe plasma transport. The feasibility of the transformation theory for plasma transport was demonstrated.As potential applications, we designed three model devices capable of cloaking, concentrating, and rotating plasmas without disturbing the density profile of plasmas in the ...  相似文献   
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Transformation optics provides great versatility for precisely manipulating electromagnetic waves. It has been extended to other fields including acoustics, thermotics, and electrics. Taking advantage of the transformation electrics method, we demonstrate that the square-shaped cloak can guide electric current around the cloaked region smoothly without perturbing the exterior electric current. And the cylindrical rotator can rotate the electric current.Inside the enclosed domain of the rotator, the electric current from the outside will appear as if it is coming from a different angle. Finally, the related experimental realizations and potential applications are also discussed.  相似文献   
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这篇综述回顾了我们今年来在铁磁流体方面的一些研究工作。铁磁流体是一种纳米磁颗粒或亚铁磁颗粒悬浮在基液(如:水或煤油)中形成的悬浮液。铁磁流体之所以受到广泛关注,是因为它们在许多方面都有着潜在应用,例如在机械工程和生物医学等领域。再次综述中,我们首先介绍了铁磁流体的场感应各向异性结构,然后,介绍了几种铁磁流体基软物质材料的光学性质,即:光学负折射、磁控光子待隙和非线性光学响应。我们采用的研究方法主要是分子动力学模拟,有效煤质近似和有限元模拟.  相似文献   
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The detection of macromolecular conformation is particularly important in many physical and biological applications. Here we theoretically explore a method for achieving this detection by probing the electricity of sequential charged segments of macromolecules. Our analysis is based on molecular dynamics simulations, and we investigate a single file of water molecules confined in a half-capped single-walled carbon nanotube (SWCNT) with an external electric charge of +e or -e (e is the elementary charge). The charge is located in the vicinity of the cap of the SWCNT and along the centerline of the SWCNT. We reveal the picosecond timescale for the re-orientation (namely, from one unidirectional direction to the other) of the water molecules in response to a switch in the charge signal, -e → +e or +e →-e. Our results are well understood by taking into account the electrical interactions between the water molecules and between the water molecules and the external charge. Because such signals of re-orientation can be magnified and transported according to Tu et al. [2009 Proc. Natl. Acad. Sci. USA 106 18120], it becomes possible to record fingerprints of electric signals arising from sequential charged segments of a macromolecule, which are expected to be useful for recognizing the conformations of some particular macromolecules.  相似文献   
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It is important to know whether the laws or phenomena in statistical physics for natural systems with non-adaptive agents still hold for social human systems with adaptive agents, because this implies whether it is possible to study or understand social human systems by using statistical physics originating from natural systems. For this purpose, we review the role of human adaptability in four kinds of specific human behaviors, namely, normal behavior, herd behavior, contrarian behavior, and hedge behavior. The approach is based on controlled experiments in the framework of market-directed resource-allocation games. The role of the controlled experiments could be at least two-fold: adopting the real human decision-making process so that the system under consideration could reflect the performance of genuine human beings;making it possible to obtain macroscopic physical properties of a human system by tuning a particular factor of the system,thus directly revealing cause and effect. As a result, both computer simulations and theoretical analyses help to show a few counterparts of some laws or phenomena in statistical physics for social human systems: two-phase phenomena or phase transitions, entropy-related phenomena, and a non-equilibrium steady state. This review highlights the role of human adaptability in these counterparts, and makes it possible to study or understand some particular social human systems by means of statistical physics coming from natural systems.  相似文献   
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张利锋  黄吉平 《中国物理 B》2010,19(2):24213-024213
By utilizing the electrorheological effect, three-dimensional colloidal crystals can be produced, whose lattice struc-ture can be changed from the body-centered-tetragonal lattice to other lattices under the application of electric fields. This paper calculates photonic band structures of such crystals with lattice structure transformation, and demonstrates the existence of complete band gaps for some intermediate lattices. Thus, it becomes possible to use the electrorheo-logical effect to achieve photonic crystals with desired photonic gap properties resulting from tunable structures.  相似文献   
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We exploit theoretically a class of rectangular cylindrical devices for noise shielding by using acoustic metamateriais. The function of noise shielding is justified by both the far-field and near-field full-wave simulations based on the finite element method. The enlargement of equivalent acoustic scattering cross sections is revealed to be the physical mechanism for this function. This work makes it possible to design a window with both noise shielding and air flow.  相似文献   
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 简单言之, “物理”二字的意思就是“物质之理”。不言自明, 这里的“物质”是指自然界中无智能的“物”, 例如原子、电子等。这里所说的“无智能”主要指, 这些物质没有学习能力、对外界环境没有适应性, 举个例子:若有两个原子, 沿着同一轨道相向而行, 它们必然相撞;今天撞了, 如果明天再遇到同样的情况, 这两个原子仍旧会相撞。为什么?因为这些原子没有学习能力, 它们“不长记性”、“记不住”已经发生的事情, 所以, 下次再相遇时, 该发生什么还发生什么, 换言之, 因为它们没有学习能力, 所以, 它们对外界环境也就没有适应性。事实上, 也正因为“物理”关心的是无智能的物质系统, 所以, 它们可以用简单的物理原理来描述、理解、预测, 例如牛顿第二定律、万有引力定律等。在这些原理中, 人们不必额外引入描述学习能力和适应性的物理量, 可能也正因此, 物质世界在物理学家的眼中是简单的, 物理学家总喜欢用一些简单的物理原理来解释和预言我们所在的这个物质世界。例如, 理论物理学家们正在刻苦攻关的大统一理论正是这样的一个理想的、“简单”的理论, 期望它能解释宇宙中各种自然力之间的关系。  相似文献   
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通过对声子晶体负折射的实验和理论进行梳理,提出可以通过从对称性角度理解声波在周期性结构中的散射,来理解声学负折射现象的物理机制.在此启发下,本文继而运用有限元模拟,通过改变背景介质的声学常数,成功展示了声波在声子晶体中的负折射现象.  相似文献   
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