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两道巴蒂金电动力学题的启示 总被引:4,自引:4,他引:0
由巴蒂金两道与电象有关的相互作用能与相互作用力的习题的巧妙解答,证明关于电象情形与真实情形的相互作用力桢,而相互作用能不一定是半值关系的结论是正确的,并解释了是否为半值关系的深刻物理内涵。 相似文献
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教科书在推导出电荷q在电场中从A点移到B过程中,电场力所作的功和电势差的关系WAB=qUAB之后得出下面两个结论:结论1:沿电场线方向,电势逐点降低;结论2:电场力作正功时,正电荷是从电势高的地方移向电势低的地方;负电行是从电势低的地方移向电势高的地方.反之,只要正、负电荷这样移动,电场力一定做正功.学生对这样的结论只是记忆而难以理解,教学中如能举一反三,并加以归纳总结,有助于学生正确理解并加强记忆·下面分别从四种情况加以说明.①在正电荷形成的电场中,正检验电荷从A点移到B点,电场力作正功.U在减小.②在… 相似文献
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基于射频识别技术原理及Friis传输方程, 导出了无源超高频射频识别系统链路模型, 结合二端口网络分析方法, 导出了标签密集环境下的标签天线互阻抗计算表达式.利用单阅读器单标签时的标签阻抗匹配条件, 基于功率传输系数及调制因子, 分析了互偶效应对系统链路的影响.在开阔室内环境中, 测试了双标签及标签单、双平面布置情形下的阅读器天线最小发射功率及系统识别率.测试结果表明, 双标签及双平面情形下, 阅读器天线最小发射功率变化率分别为(-7%, 11.6%)及(-10%, 12.5%).
关键词:
射频识别
密集环境
互偶效应
互阻抗 相似文献
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正确地运用电象法关于电象与原电荷之间的互作用能问题 总被引:3,自引:3,他引:0
电像法求解问题的实质,是在求解区域之外寻找一个虚电荷,来等效地代替实际导体面或介质分界面上的感应电荷[1].值得注意的是,(1)必须在求解区域以外找.(2)这个象电荷是个虚假的电荷,不是一个与原电荷无关的独立真实电荷.(3)真实电荷是导体面或介质分界面上的感应电荷,感应电荷的总量并不一定总是等于象电荷.但是在实际应用中,往往忽视后二点,把象电荷视作为与原电荷无关的独立的真实电荷,而把等效替代视作为完全代替,这是不妥当的.下面以一常见的习题例说明之.并由此引出,电象与原电荷之间的互作用能仅仅是把电象换成与它
相同的真实电荷… 相似文献
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Hg原子光谱中的253.652nm互组合线翁斯灏(中国高科技中心,华东师范大学物理系,上海200062)一、互组合跃迁1914年,德国物理学家J.Franck和G.Hertz利用电子与气体原子在非弹性碰撞中能量交换的分立特征,证明原子体系量子态的存在... 相似文献
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施感电荷与感应电荷之间相互作用能的计算及应用 总被引:2,自引:2,他引:0
导出了将一个原来不带电的导体移到一组固定电荷的电场中时,施感电荷与导体上的感应电荷之间的相互作用能公式,并把所得的公式应用到电象法中,得到了一些有价值的结果. 相似文献
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不带电荷的导体移到点电荷的静电场中时,导体表面会产生感应电荷.我们证明对任意形状的导体,导体和点电荷之间的相互作用能是点电荷与其镜象电荷之间库仑作用能的1/2,并且对此结果给出一个非常简单的解释. 相似文献
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Charges inside a dielectric object embedded in a dissimilar dielectric medium polarize the surrounding medium, which in turn makes a contribution, called the reaction field, to the electric field inside the object. In this work, we develop complete image systems for the reaction field inside a prolate or oblate spheroidal dielectric object embedded in an infinite dissimilar dielectric medium. In either case, an image system consists of a point image and a symmetric surface image over an exterior confocal spheroid that passes through the point image. As an application, the point image is applied into the generalized image charge solvation model (GICSM) and is tested in simulations of liquid water, and the results are analyzed in comparison with those obtained from the ICSM simulation as references. The results indicate that, for both the prolate and oblate cases, the single point image charge approximation for the reaction field inside the dielectric cavity of the model is good enough for the GICSM to faithfully reproduce typical static and dynamic properties of the liquid water at least when the spheroidal cavity has relatively small eccentricity. 相似文献
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The coherent dynamics of two interacting carriers in one-dimensional quantum dot arrays driven by oscillating electric fields is theoretically investigated with the help of numerical calculations. The coherent localization of two electrons and that of an electron–hole pair are studied in this paper. For the two-electron case, the dynamic localization of the electrons is achieved when the Coulomb interaction is large enough. In this coherent localization, the Coulomb repulsion helps the electrons to be localized. For an electron–hole pair, although the dynamic localization of the composite particle does not occur due to charge neutrality, a different type of coherent localization can occur. These phenomena are explained by the quasienergy spectra based on Floquet analysis. 相似文献
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Particles inside electrolytes with ion-specific interactions,their effective charge distributions,and effective interactions
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In this work, we explore the statistical physics of colloidal particles that interact with electrolytes via ion-specific interactions. Firstly we study particles interacting weakly with electrolyte using linear response theory. We find that the mean potential around a particle is linearly determined by the effective charge distribution of the particle, which depends both on the bare charge distribution and on ion-specific interactions. We also discuss the effective interaction between two such particles and show that, in the far field regime, it is bilinear in the effective charge distributions of two particles. We subsequently generalize the above results to the more complicated case where particles interact strongly with the electrolyte.Our results indicate that in order to understand the statistical physics of non-dilute electrolytes, both ion-specific interactions and ionic correlations have to be addressed in a single unified and consistent framework. 相似文献
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Stefan Hollands 《Annalen der Physik》2001,10(10):859-883
We consider a self‐interacting, perturbative Klein‐Gordon quantum field in a curved spacetime admitting a Killing vector field. We show that the action of this spacetime symmetry on interacting field operators can be implemented by a Noether charge which arises, in a certain sense, as a surface integral over the time‐component of some interacting Noether current‐density associated with the Killing field. The proof of this involves the demonstration of a corresponding set of Ward identities. Our work is based on the perturbative construction by Brunetti and Fredenhagen (Commun. Math. Phys. 208 (2000) 623—661) of self‐interacting quantum field theories in general globally hyperbolic spacetimes. 相似文献
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分析光场与高聚物相互作用的微观机制,介绍高分子与小分子在光场作用下的极化过程。对在窄束光场作用下,高分子链极化后链上各处极化程度的分布情况进行研究,指出对于高度拉伸的聚合物薄膜,电偶极子模型不适合准确解释高分子与光场相互作用的微观机制。为此,采用符合实际的天线模型分析高分子天线与窄束光场的相互作用,从理论上推导出天线模型高分子链上一小段的极化公式,并用离散变分方法——DVM(discrete variational method)计算一个高分子链的极化分布,验证了文中推导出的分式的合理性。最后,将极化分布看作是电流在天线上的分布,计算了天线的次级辐射在空间中的角分布,得到天线模型对电偶极子模型的修正因子。 相似文献
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Interaction, polarization, and charges or electric field distribution of conducting spheres in applied electric field are in many fields including electrorheological fluids, electrophoresis, and electrical engineering. A system with two equipotential conducting spheres in an applied uniform electric field is analyzed by image method. A new method is put forward to calculate the image charges distribution when using image method, which ensures the validity of image method to analyze equipotential cases. An apparatus is constructed to measure the force experimentally as well. Results show that the distribution of electric field and electric interaction are different with the case not equipotential. 相似文献
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In this review we discuss the chaotic dynamics (both classical and quantal aspects) of a simple atomic system, namely hydrogen
atom interacting with time independent and time dependent external fields. These include: i) static electric field, ii) static
magnetic field, iii) combined electric and magnetic fields, in parallel and perpendicular configuration, iv) instantaneous
and generalized van der Waals field, v) mass anisotropy and vi) linearly and circularly polarized microwave fields. 相似文献
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研究了单模辐射场与耦合双原子Raman相互作用过程中光场的量子特性,讨论了系统耦合常数和初始状态对光场量子特性的影响. 相似文献