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.
标签： cylindrical scattering expansion developed
上传时间： 2017-03-30
上传用户：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.
标签： distribution dimensional transport obtained
上传时间： 2013-12-19
上传用户：zhliu007
java面试笔试题大汇总 ~很全面 java面试笔试题大汇总 第一，谈谈final, finally, finalize的区别。 最常被问到。 第二，Anonymous Inner Class (匿名内部类) 是否可以extends(继承)其它类，是否可以implements(实现)interface(接口)? 第三，Static Nested Class 和 Inner Class的不同，说得越多越好(面试题有的很笼统)。 第四，&和&&的区别。 这个问得很少。 第五，HashMap和Hashtable的区别。 常问。 第六，Collection 和 Collections的区别。 你千万别说一个是单数一个是复数。 第七，什么时候用assert。 API级的技术人员有可能会问这个。 第八，GC是什么? 为什么要有GC? 基础。 第九，String s = new String("xyz") 创建了几个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 有什么错? short s1 = 1 s1 += 1 有什么错? 面试题都是很变态的，要做好受虐的准备。 第十二，sleep() 和 wait() 有什么区
上传时间： 2017-05-20
上传用户：坏坏的华仔
orcle单表多表练习，select语句，Inner join等基本语句的练习
标签： orcle
上传时间： 2016-05-29
上传用户：紫嫣梦天
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.
标签： electromagnetic response Seismic control using
上传时间： 2021-11-04
上传用户：a1293065
