共查询到20条相似文献,搜索用时 234 毫秒
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在自行设计的微波干馏装置上研究了汪清和桦甸几个矿区的油页岩和半焦在微波场中升温特性.实验研究了产地、组成成分对油页岩升温特性的影响,不同干馏终温生成的半焦及石墨在微波场中的升温特性,以及半焦和油页岩混合物在微波场中的升温特性.实验结果表明:油页岩是一种微波弱吸收物质,要想热解必须加入微波吸收剂.水分对油页岩在微波场中的升温特性影响很大.油页岩干燥以后,升温速率明显减小,终温也降低.油页岩中的黄铁矿对升温也有一定的影响.半焦由于在微波场中升温很快可以作为油页岩热解的微波吸收剂.半焦的升温速率与干馏终温有关,随着干馏终温提高,半焦在微波场中的升温速率变大.半焦和页岩的混合物在微波场中升温很快,具有良好的热解效果. 相似文献
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稀土永磁材料被大量使用在微波管中,其温度系数是影响微波管研制成功率的关键参数之一,因此,永磁材料温度系数的检测十分必要。本文使用了一种简单易行的实验方法,在普通实验室可以快速而准确地检测永磁材料的温度系数。分析表明,该实验方法是可靠的,测得的温度系数值是可信的。同时该方法对高低温下磁性材料的检测有一定的借鉴作用。 相似文献
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提出了一种基于受激布里渊散射(SBS)及吸收光谱的橄榄油等级鉴别方法。采用紫外-可见吸收光谱法对不同等级的橄榄油进行检测,依据所获得光谱吸收峰的数量及位置可以实现各等级橄榄油的初步鉴别与分析。在吸收光谱实验的基础上,采用SBS光谱法,通过测量不同温度下各等级橄榄油的SBS光谱,分析SBS频移随温度的变化。实验结果表明:不同等级橄榄油的布里渊光谱随温度的变化特性一致,即布里渊频移随温度升高而减小,但不同等级橄榄油具有其独特的频移特征曲线。通过两种光谱法的结合,可以有效、快速地鉴别橄榄油等级。 相似文献
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采用单喇叭法测量地表介质复介电常数的系统简单,操作使用方便,特别适用于测量各种路面、土壤及厚块材料等场合,并可制成便携式设备。如将计算公式等形成相应软件构成仪器组成部分,使用时只要测试出原始数据,即可通过机内软件计算并显示出待测材料的复介电常数。 相似文献
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Deshpande M.D. Reddy C.J. Tiemsin P.I. Cravey R. 《Microwave Theory and Techniques》1997,45(3):359-366
In this paper, a simple waveguide measurement technique is presented to determine the complex dielectric constant of a dielectric material. The dielectric sample is loaded in a short-circuited rectangular waveguide. Using a network analyzer, the reflection coefficient of the waveguide is measured. Using the finite-element method (FEM) the exact reflection coefficient of this configuration is determined as a function of the dielectric constant. The measured and calculated values of the reflection coefficient are then matched using the Newton-Raphson method to estimate the dielectric constant of a material. A comparison of estimated values of the dielectric constant obtained from simple waveguide modal theory and the FEM approach is presented. Numerical results for dielectric constants of Teflon and Plexiglas measured at the X- and Ku-bands are presented. Numerical inaccuracies in the estimate of the dielectric constant due to: 1) the presence of airgaps between sample and sample holder waveguide surfaces and 2) inaccuracy in the sample dimensions are also discussed 相似文献
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《Microwave Theory and Techniques》1982,30(12):2139-2145
Approximate methods are used to obtain the modal properties of stripe-contact semiconductor injection lasers using a planar three-layer waveguide model. The central active layer has a dielectric constant that varies smoothly along the direction parallel to the heterojunction boundaries. The complex dielectric constant under the stripe contact is dependent on the gain and approaches a constant value at large lateral distances. The two methods are compared in terms of their modal propagation constants. An application of the effective index method facilitates a physical understanding of dielectric waveguide modes as well as providing an efficient calculation procedure. 相似文献
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Three continuous profiles for the dielectric constant are derived, which allow exact solutions of the vector wave equation, including all terms in the gradient of the profile, for both TE and TM modes on slab waveguides. The dielectric constant has been assumed to be a scalar quantity; i.e., the medium is isotropic. 相似文献
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一种新的微波频率下混合电解质水溶液复等效介电常数的计算方法 总被引:4,自引:0,他引:4
目前,大部分电解质水溶液的等效介电常数计算模型是针对静止频率下其实部进行的.而对于实部与虚部同时计算方法的报道中,都是通过大量实验测量,利用德拜参数拟合而得到相应结果的,且局限于少数几种溶液,例如盐水和海水等.本文中,通过实验得到了不同电解质水溶液的复等效介电常数,基于此实验结果,提出了一个新的计算模型,引入了不同离子的复影响因子的概念,用来计算微波频率下电解质水溶液的复等效介电常数.在915MHz和2450MHz下,比较了实验结果和计算结果,它们比较好地符合,从而证明了公式的有效性.这将为微波化学中微波加热稀溶液化学反应中的电磁场和温度分布计算提供基础,同时也将对地球物理、遥感以及水污染监测等相关领域研究有帮助. 相似文献
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The iterative forward-backward (FB) method is a recently proposed efficient technique for numerical evaluation of scattering from perfectly conducting rough surfaces. Extension of the method to include scattering from imperfect conducting surfaces, with a high imaginary part of the complex dielectric constant, has also been proposed. The FB method is further generalized to analyze scattering from dielectric rough surfaces with arbitrary complex dielectric constant. Electric and magnetic equivalent surface currents are split into forward and backward components and equations governing these current components are obtained. As a solution, an iterative scheme is proposed and its convergence rate is analyzed. Finally, the effectiveness of the method is assessed by comparing the obtained scattering results with "exact" ones, computed by employing the usual method of moments (MoM). 相似文献
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采用聚合物前驱体法制备了单一铋系层状钙钛矿相SrBi2Ta2O9粉体,研究了不同烧成温度对SrBi2Ta2O9陶瓷相结构和介电、铁电性能的影响。结果表明,随着烧成温度的升高,晶粒沿c轴择优取向趋势增强;不同烧成温度下陶瓷介电常数和损耗均随频率升高而降低,1000℃时陶瓷有最大介电常数和较小的损耗,且陶瓷有较大的剩余极化值和较小的矫顽电场,分别为3.884μC/cm2和25.37kV/cm。不同Ca掺杂量掺杂后,SrBi2Ta2O9陶瓷的介电常数、损耗和剩余极化值均显著降低。 相似文献