It was proposed that perfect invisibility cloaks can be constructed for hiding objects from electromagnetic illumination (Pendry et al., Science 312, p. 1780). The cylindrical cloaks experimentally demonstrated (Schurig et al., Science 314, p. 997) and theoretically proposed (Cai et al., Nat. Photon. 1, p. 224) have however simplified material parameters in order to facilitate easier realization as well as to avoid infinities in optical constants. Here we show that the cylindrical cloaks with simplified material parameters inherently allow the zeroth-order cylindrical wave to pass through the cloak as if the cloak is made of a homogeneous isotropic medium, and thus visible. To all high-order cylindrical waves, our numerical simulation suggests that the simplified cloak inherits some properties of the ideal cloak, but finite scatterings exist.
標(biāo)簽： invisibility constructed proposed electrom
上傳時(shí)間： 2013-12-18
上傳用戶：13215175592
A cylindrical wave expansion method is developed to obtain the scattering field for an ideal two-dimensional cylindrical invisibility cloak. A near-ideal model of the invisibility cloak is set up to solve the boundary problem at the inner boundary of the cloak shell. We confirm that a cloak with the ideal material parameters is a perfect invisibility cloak by systematically studying the change of the scattering coefficients from the near-ideal case to the ideal one. However, due to the slow convergence of the zeroth order scattering coefficients, a tiny perturbation on the cloak would induce a noticeable field scattering and penetration.
標(biāo)簽： cylindrical scattering expansion developed
上傳時(shí)間： 2017-03-30
上傳用戶：lhc9102
In an electromagnetic cloak based on a transformation approach, reduced sets of material properties are generally favored due to their easier implementation in reality, although a seemingly inevitable drawback of undesired reflection exists in such cloaks. Here we suggest using high-order transformations to create smooth moduli at the outer boundary of the cloak, therefore completely eliminating the detrimental scattering within the limit of geometric optics. We apply this scheme to a non-magnetic cylindrical cloak and demonstrate that the scattered field is reduced substantially in a cloak with optimal quadratic transformation as compared to its linear counterpart.
標(biāo)簽： electromagnetic transformation properties approach
上傳時(shí)間： 2017-03-30
上傳用戶：pkkkkp
We obtained the energy transport velocity distribution for a three dimensional ideal cloak explicitly. Near the operation frequency, the energy transport velocity has rather peculiar distribution. The velocity along a line joining the origin of the cloak is a constant, while the velocity approaches zero at the inner boundary of the cloak. A ray pointing right into the origin of the cloak will experience abrupt changes of velocities when it impinges on the inner surface of the cloak. This peculiar distribution causes long time delays for beams passing through the ideal cloak within a geometric optics description.
標(biāo)簽： distribution dimensional transport obtained
上傳時(shí)間： 2013-12-19
上傳用戶：zhliu007
In computer vision, sets of data acquired by sampling the same scene or object at different times, or from different perspectives, will be in different coordinate systems. Image registration is the process of transforming the different sets of data into one coordinate system. Registration is necessary in order to be able to compare or integrate the data obtained from different measurements. Image registration is the process of transforming the different sets of data into one coordinate system. To be precise it involves finding transformations that relate spatial information conveyed in one image to that in another or in physical space. Image registration is performed on a series of at least two images, where one of these images is the reference image to which all the others will be registered. The other images are referred to as target images.
標(biāo)簽： different computer acquired sampling
上傳時(shí)間： 2013-12-28
上傳用戶：來茴
SA Encryption and Decryption using Matlab The program set contains thirteen files listed below. errormeg.fig errormsg.m helpmsg.fig helpmsg.m inputmsg.fig inputmsg.m mesgcut.m pro2.fig pro2.m rsacore.m readme.txt screenshot.gif In order to run the program please call pro2.m under Matlab 6.0 Environment. System Requirement Matlab version 6.0 and if necessary, Maple version 6.0 on any platform PentiumII 300 MHz or equivalent.
標(biāo)簽： Encryption Decryption contains thirteen
上傳時(shí)間： 2017-04-06
上傳用戶：dreamboy36
1. It is located in the root directory - SecurityBuilderDemo.exe. Leave password box blank and click on Security button in order to Add/Remove users and set user rights. Once you entered Security dialog you may select your Supervisor password. 2. Click OK when finished configuring users. Don t forget to disable some features in order to see what happens with GUI elements - menus, and buttons.
標(biāo)簽： SecurityBuilderDemo directory password located
上傳時(shí)間： 2014-01-23
上傳用戶：chongcongying
c pgm to find redundant paths in a graph.Many fault-tolerant network algorithms rely on an underlying assumption that there are possibly distinct network paths between a source-destination pair. Given a directed graph as input, write a program that uses depth-first search to determine all such paths. Note that, these paths are not vertex-disjoint i.e., the vertices may repeat but they are all edge-disjoint i.e., no two paths have the same edges. The input is the adjacency matrix of a directed acyclic graph and a pair(s) of source and destination vertices and the output should be the number of such disjoint paths and the paths themselves on separate lines. In case of multiple paths the output should be in order of paths with minimum vertices first. In case of tie the vertex number should be taken in consideration for ordering.
標(biāo)簽： fault-tolerant algorithms redundant underlyin
上傳時(shí)間： 2013-12-18
上傳用戶：jkhjkh1982
Fortran 90 versions of all the Numerical Recipes routines appear in the following Chapters B1 through B20, numbered in correspondence with Chapters 1 through 20 in Volume 1. Within each chapter, the routines appear in the same order as in Volume 1, but not broken out separately by section number within Volume 1鈥檚 chapters. There are commentaries accompanying many of the routines, generally following the printed listing of the routine to which they apply. These are of two kinds: issues related to parallelizing the algorithm in question, and issues related to the Fortran 90 implementation. To distinguish between these two, rather different, kind
標(biāo)簽： Numerical following the Chapters
上傳時(shí)間： 2017-04-12
上傳用戶：6546544
SQL中的單記錄函數(shù) 1.ASCII 返回與指定的字符對應(yīng)的十進(jìn)制數(shù) SQL> select ascii( A ) A,ascii( a ) a,ascii( 0 ) zero,ascii( ) space from dual A A ZERO SPACE --------- --------- --------- --------- 65 97 48 32 2.CHR 給出整數(shù),返回對應(yīng)的字符 SQL> select chr(54740) zhao,chr(65) chr65 from dual ZH C -- -
標(biāo)簽： ascii SQL select ASCII
上傳時(shí)間： 2017-04-14
上傳用戶：330402686
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