584,429 research outputs found

    A Double Layer Electromagnetic Cloak And GL EM Modeling

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    In this paper, we propose a novel electromagnetic (EM) cloaking structure that consists of two annular layers between three spherical shells and model its performance numerically and theoretically by using a Global and Local EM field (GL) method. The two annular layers contain distinct cloaking materials: the outer layer provides invisibility; the inner layer is fully absorbing. The cloaking materials are weakly degenerative. The wavefield from an EM source located outside the cloak propagates as in free space outside the outer shell, never be disturbed by the cloak and does not penetrate into the inner absorbing layer and concealment. The field of a source located inside inner layer or the cloaked concealment is completely absorbed by the inner layer and never reaches the outside of the middle shell, Moreover, the EM wavefield excited in concealment is not disrupted by the cloak. There exists no Maxwell EM wavefield can be excited in a single layer cloaked concealment which is filled by normal material. Moreover, we find a negative dielectric and positive susceptibility metamaterial to fill into the concealment, such that the interior EM wave propagates from the concealment to free space through the single layer cloak. Therefore, the double layer cloak is important and necessary for complete invisibility. Numerical simulations and theoretical analysis verifying these properties are performed using the GL EM modeling method that we described in this paper.Comment: A Novel GL double Layer cloaks are proposed. Moreover, we discovered a single negative refractive index metamaterial. We fill it inside the single cloaked concealment, the EM wave field excited inside the this material in the concealment propagates out to free space through the single layer cloak. 13 figures are include

    A Multigrid Method for the Ground State Solution of Bose-Einstein Condensates

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    A multigrid method is proposed to compute the ground state solution of Bose-Einstein condensations by the finite element method based on the multilevel correction for eigenvalue problems and the multigrid method for linear boundary value problems. In this scheme, obtaining the optimal approximation for the ground state solution of Bose-Einstein condensates includes a sequence of solutions of the linear boundary value problems by the multigrid method on the multilevel meshes and a series of solutions of nonlinear eigenvalue problems on the coarsest finite element space. The total computational work of this scheme can reach almost the optimal order as same as solving the corresponding linear boundary value problem. Therefore, this type of multigrid scheme can improve the overall efficiency for the simulation of Bose-Einstein condensations. Some numerical experiments are provided to validate the efficiency of the proposed method.Comment: 15 pages and 6 figures. arXiv admin note: substantial text overlap with arXiv:1405.715

    A GL Double Layer EM Cloaks In Broad Frequency Band And Reciprocal Law

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    In this paper, we propose a novel GLWF double layer EM cloak in the broad frequency band. The GLWF double layer cloak consists of two sphere annular layers, two type cloak materials are proposed and installed in its each layer, respectively. The outer layer of the GL cloak has the invisible function in broad frequency band, while its inner layer has the fully absorption and rapid delay function. The GLWF double layer cloak overcomes the following difficulties of the single layer PS cloak. (1) There exists no EM wavefield can be excited inside the concealment of the PS cloak, the concealment of the PS cloak is blind. Our GL double layer cloak recovered that the EM wave field can be excited inside the concealment of the GL double layer cloak. (2) There is exceeding light speed physical violation in PS cloak, its invisibility only in very narrow frequency band. Our GLWF double layer cloak corrects the violation. (3) The reciprocal law is satisfied in our GL double cloak media. However, the PS cloak damaged the reciprocal law.. The simulations and comparisons of the EM wave field propagation through the GLWF double cloak, GL double cloak and GL double layer with PS outer layer are presented to show the advantages of the GLWF double layer EM cloak The GL double layer cloaks are proposed by our GL EM modeling and inversion. The 3D GL EM modeling simulations for the double layer cloak are presented. The copyright and patent of the GLWF double layer cloak materials and GL EM modeling and inversion in this paper are reserved by authors in GL Geophysical Laboratory.Comment: 8 pages and 11 figures are included in this paper. Please send comments to [email protected]

    Computable Error Estimates for Ground State Solution of Bose-Einstein Condensates

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    In this paper, we propose a computable error estimate of the Gross-Pitaevskii equation for ground state solution of Bose-Einstein condensates by general conforming finite element methods on general meshes. Based on the proposed error estimate, asymptotic lower bounds of the smallest eigenvalue and ground state energy can be obtained. Several numerical examples are presented to validate our theoretical results in this paper.Comment: 19 pages, 9 figures. arXiv admin note: text overlap with arXiv:1601.0156

    Problem On The Acoustic Cloak By 00 to R1R_1 Transformation

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    The 00 to R1R_1 radial spherical coordinate transformation method can be making electromagnetic (EM) invisible cloak. However the cloak by transformation optic has infinite speed and exceeding light speed etc fundamental difficulties. In this paper, we discover problem on acoustic cloak by transformation and prove that in the 00 to R1R_1 radial spherical coordinate transformation, the pressure wave field P(rp)=P(r)P(r_p)=P(r) is invariant, in the physical inner spherical surface boundary r=R1r=R_1, P(R1)P(R_1) is not zero. the acoustic field propagation penetrate into the inner sphere r<R1r < R_1.Therefore, the inner sphere r<R1r < R_1 can not be cloaked. The GL simulation figures of the pressure acoustic wave propagation penetrate into the inner sphere rR1r \le R_1 are presented in figure 1 to figure 12.The pressure wave is setting to zero that cause the scattering wave to disturb incident pressure acoustic wave outside of the outer sphere rR2r \ge R_2 that make the whole sphere rR2r \ge R_2 will be deltected. GL method simulation is presented in figure 13. we discovered and proved that 00 to R1R_1 sphere radial transformation can not be used to induce acoustic no scattering cloak.Comment: 18 pages, 112 formulas and 2 figures in this paper, Welcome comments from colleagues. It is academical publication for open review. Please colleague send comments and question to me by email [email protected]. If colleague use this paper, please be sure cite my paper in his papers. The Paper is different from other paper

    Soft supersymmetry breaking of 4d N=2\mathcal{N}=2 SCFT

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    A classification of soft SUSY breaking deformation of general four dimensional N=2\mathcal{N}=2 SCFT is provided. Given the large class of newly discovered N=2\mathcal{N}=2 SCFTs and their known properties such as the central charges and full information of BPS operators, it is possible to get a huge number of new N=1\mathcal{N}=1 SCFTs and non-supersymmetric CFTs. Many properties of these new N=1\mathcal{N}=1 SCFTs such as central charges, chiral spectrum and Seiberg duality can be derived from known information of parent N=2\mathcal{N}=2 SCFT.Comment: 17 pages, 2 figure

    Talk&Learn: Improving Conversation Experience and Creating Opportunities for Foreign Language Learning

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    Existing Real-Time Translation Interfaces (RTTI) do not provide experience as natural and efficient as monolingual communication. Also, such systems do not provide functions supporting language learning. This results in the waste of both time and potential language context. In order to overcome the above limitations, we propose a solution named "Talk&Learn". Its core idea is to rearrange ("Delay-Match") the real-time videos and translated texts or speeches, so as to gain better naturalness and efficiency. At the same time, this will create extra free time for users. So we further propose to utilize the free time for contextual language learning

    Model for processive nucleotide and repeat additions by the telomerase

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    A model is presented to describe the nucleotide and repeat addition processivity by the telomerase. In the model, the processive nucleotide addition is implemented on the basis of two requirements: One is that stem IV loop stimulates the chemical reaction of nucleotide incorporation, and the other one is the existence of an ssRNA-binding site adjacent to the polymerase site that has a high affinity for the unpaired base of the template. The unpairing of DNA:RNA hybrid after the incorporation of the nucleotide paired with the last base on the template, which is the prerequisite for repeat addition processivity, is caused by a force acting on the primer. The force is resulted from the unfolding of stem III pseudoknot that is induced by the swinging of stem IV loop towards the nucleotide-bound polymerase site. Based on the model, the dynamics of processive nucleotide and repeat additions by Tetrahymena telomerase are quantitatively studied, which give good explanations to the previous experimental results. Moreover, some predictions are presented. In particular, it is predicted that the repeat addition processivity is mainly determined by the difference between the free energy required to disrupt the DNA:RNA hybrid and that required to unfold the stem III pseudoknot, with the large difference corresponding to a low repeat addition processivity while the small one corresponding to a high repeat addition processivity.Comment: 28 pages, 5 figure

    Some examples of quasiisometries of nilpotent Lie groups

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    We construct quasiisometries of nilpotent Lie groups. In particular, for any simply connected nilpotent Lie group N, we construct quasiisometries from N to itself that is not at finite distance from any map that is a composition of left translations and automorphisms. We also construct biLipschitz maps of the Heisenberg groups that send vertical lines to non-vertical curves

    Three dimensional Seiberg-like duality and tropical cluster algebra

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    Seiberg-like duality of three dimensional N=2 Chern-Simons-Matter quiver gauge theory is shown to have a chiral double tropical cluster algebra structure. We use cluster algebra results to study combinatorial aspects of these theories such as classification, supersymmetry breaking, etc.Comment: 18 pages, 5 figures. References added, typo correcte
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