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.
標簽： cylindrical scattering expansion developed
上傳時間： 2017-03-30
上傳用戶：lhc9102
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.
標簽： distribution dimensional transport obtained
上傳時間： 2013-12-19
上傳用戶：zhliu007
java面試筆試題大匯總 ~很全面 java面試筆試題大匯總 第一，談談final, finally, finalize的區別。 最常被問到。 第二，Anonymous Inner Class (匿名內部類) 是否可以extends(繼承)其它類，是否可以implements(實現)interface(接口)? 第三，Static Nested Class 和 Inner Class的不同，說得越多越好(面試題有的很籠統)。 第四，&和&&的區別。 這個問得很少。 第五，HashMap和Hashtable的區別。 常問。 第六，Collection 和 Collections的區別。 你千萬別說一個是單數一個是復數。 第七，什么時候用assert。 API級的技術人員有可能會問這個。 第八，GC是什么? 為什么要有GC? 基礎。 第九，String s = new String("xyz") 創建了幾個String Object? 第十，Math.round(11.5)等於多少? Math.round(-11.5)等於多少? 第十一，short s1 = 1 s1 = s1 + 1 有什么錯? short s1 = 1 s1 += 1 有什么錯? 面試題都是很變態的，要做好受虐的準備。 第十二，sleep() 和 wait() 有什么區
上傳時間： 2017-05-20
上傳用戶：壞壞的華仔
orcle單表多表練習，select語句，Inner join等基本語句的練習
標簽： orcle
上傳時間： 2016-05-29
上傳用戶：紫嫣夢天
This paper presents a new type of electromagnetic damper with rotating inertial mass that has been devel oped to control the vibrations of structures subjected to earthquakes. The electromagnetic inertial mass damper (EIMD) consists of a ball screw that converts axial oscillation of the rod end into rotational motion of the internal flflywheel and an electric generator that is turned by the rotation of the Inner rod. The EIMD is able to generate a large inertial force created by the rotating flflywheel and a variable damping force devel oped by the electric generator. Device performance tests of reduced-scale and full-scale EIMDs were under taken to verify the basic characteristics of the damper and the validity of the derived theoretical formulae. Shaking table tests of a three-story structure with EIMDs and earthquake response analyses of a building with EIMDs were conducted to demonstrate the seismic response control performance of the EIMD. The EIMD is able to reduce story drifts as well as accelerations and surpasses conventional types of dampers in reducing acceleration responses.
標簽： electromagnetic response Seismic control using
上傳時間： 2021-11-04
上傳用戶：a1293065
