We analyze, both analytically and numerically, the effectiveness of cloaking an infinite cylinder from observations by electromagnetic waves in three dimensions. We show that, as truncated approximations of the ideal permittivity and permeability tensors tend towards the singular ideal cloaking fields, so that the anisotropy ratio tends to infinity, the D and B fields blow up near the cloaking surface. Since the metamaterials used to implement cloaking are based on effective medium theory, the resulting large variation in D and B will pose a challenge to the suitability of the field averaged characterization of " and 碌. We also consider cloaking with and without the SHS (softand- hard surface) lining, shown in [6] to be theoretically necessary for cloaking in the cylindrical geometry. We demonstrate numerically that cloaking is significantly improved by the SHS lining, with both the far field of the scattered wave significantly reduced and the blow up of D and B prevented.
標(biāo)簽： effectiveness analytically numerically cloaking
上傳時(shí)間： 2017-03-30
上傳用戶：zxc23456789
《分析性寫(xiě)作》，介紹言簡(jiǎn)意賅： The popular, brief rhetoric that treats writing as thinking, WRITING analytically, Sixth Edition, offers a series of prompts that lead you through the process of analysis and synthesis and help you to generate original and well-developed ideas. The book's overall point is that learning to write well means learning to use writing as a way of thinking well. To that end, the strategies of this book describe thinking skills that employ writing. As you will see, this book treats writing as a tool of thought--a means of undertaking sustained acts of inquiry and reflection.
標(biāo)簽： Writing Analyticall
上傳時(shí)間： 2015-08-22
上傳用戶：東大寺的
Integrated EMI/Thermal Design forSwitching Power SuppliesWei ZhangThesis submitted to the Faculty of theVirginia Polytechnic Institute and State Universityin partial fulfillment of the requirements for the degree of Integrated EMI/Thermal Design forSwitching Power SuppliesWei Zhang(ABSTRACT)This work presents the modeling and analysis of EMI and thermal performancefor switch power supply by using the CAD tools. The methodology and design guidelinesare developed.By using a boost PFC circuit as an example, an equivalent circuit model is builtfor EMI noise prediction and analysis. The parasitic elements of circuit layout andcomponents are extracted analytically or by using CAD tools. Based on the model, circuitlayout and magnetic component design are modified to minimize circuit EMI. EMI filtercan be designed at an early stage without prototype implementation.In the second part, thermal analyses are conducted for the circuit by using thesoftware Flotherm, which includes the mechanism of conduction, convection andradiation. Thermal models are built for the components. Thermal performance of thecircuit and the temperature profile of components are predicted. Improved thermalmanagement and winding arrangement are investigated to reduce temperature.In the third part, several circuit layouts and inductor design examples are checkedfrom both the EMI and thermal point of view. Insightful information is obtained.
標(biāo)簽： EMI 開(kāi)關(guān)電源 英文
上傳時(shí)間： 2013-11-10
上傳用戶：1595690
Integrated EMI/Thermal Design forSwitching Power SuppliesWei ZhangThesis submitted to the Faculty of theVirginia Polytechnic Institute and State Universityin partial fulfillment of the requirements for the degree of Integrated EMI/Thermal Design forSwitching Power SuppliesWei Zhang(ABSTRACT)This work presents the modeling and analysis of EMI and thermal performancefor switch power supply by using the CAD tools. The methodology and design guidelinesare developed.By using a boost PFC circuit as an example, an equivalent circuit model is builtfor EMI noise prediction and analysis. The parasitic elements of circuit layout andcomponents are extracted analytically or by using CAD tools. Based on the model, circuitlayout and magnetic component design are modified to minimize circuit EMI. EMI filtercan be designed at an early stage without prototype implementation.In the second part, thermal analyses are conducted for the circuit by using thesoftware Flotherm, which includes the mechanism of conduction, convection andradiation. Thermal models are built for the components. Thermal performance of thecircuit and the temperature profile of components are predicted. Improved thermalmanagement and winding arrangement are investigated to reduce temperature.In the third part, several circuit layouts and inductor design examples are checkedfrom both the EMI and thermal point of view. Insightful information is obtained.
標(biāo)簽： EMI 開(kāi)關(guān)電源 英文
上傳時(shí)間： 2013-11-16
上傳用戶：萍水相逢
這是一個(gè)模擬第3類模式地震波的matlab腳本。 This a collection of Matlab scripts that solve the antiplane (mode III) earthquake dynamic problem with slip-weakening friction, on a 1D fault embedded in a 2D homogeneous elastic unbounded medium. The problem is formulated as a boundary integral equation and the elastodynamic kernels are analytically derived in the spectral domain (spatial wavenumber). The method is explained e.g. by Morrysey and Geubelle (1997), and has been improved and extensively used by Nadia Lapusta, Alain Cochard, etc.
標(biāo)簽： collection antiplane scripts matlab
上傳時(shí)間： 2013-12-26
上傳用戶：遠(yuǎn)遠(yuǎn)ssad
Sequential Monte Carlo without Likelihoods 粒子濾波不用似然函數(shù)的情況下 本文摘要:Recent new methods in Bayesian simulation have provided ways of evaluating posterior distributions in the presence of analytically or computationally intractable likelihood functions. Despite representing a substantial methodological advance, existing methods based on rejection sampling or Markov chain Monte Carlo can be highly inefficient, and accordingly require far more iterations than may be practical to implement. Here we propose a sequential Monte Carlo sampler that convincingly overcomes these inefficiencies. We demonstrate its implementation through an epidemiological study of the transmission rate of tuberculosis.
標(biāo)簽： Likelihoods Sequential Bayesian without
上傳時(shí)間： 2016-05-26
上傳用戶：離殤
We show in the context of a new economic geography model that when labor is heterogenous trade liberalization may lead to industrial agglomeration and inter-regional trade. Labor heterogeneity gives local monopoly power to firms but also introduces variations in the quality of the job match. Matches are likely to be better when there are more firms and workers in the local market, giving rise to an agglomeration force which can offset the forces against, trade costs and the erosion of monopoly power. We derive analytically a robust agglomeration equilibrium and illustrate its properties with numerical simulations
標(biāo)簽： 經(jīng)濟(jì)、城市化和經(jīng)濟(jì)增長(zhǎng)
上傳時(shí)間： 2016-04-02
上傳用戶：kinda233
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