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1.
有界电磁波在《电磁学理论》和《电动力学》中占有重要地位,但由于有界电磁波的方程是以复杂的函数式分量表示的,其物理意义抽象而不易理解。本文利用Matlab算法语言,结合有界电磁波的场方程的函数表达式,以矩形有界空间为例,直观地绘制了有界电磁波在各个层面的电场分布,便于加深对有界电磁波分布的理解。  相似文献   

2.
麦克斯韦虽然在理论上预言了电磁波的存在,但是,他并未提出过产生电磁波的任何方法.历史上,赫兹第一个通过实验发现了电磁波,并用实验证实了电磁波与光波的同一性,从而证实了麦克斯韦的电磁理论.文章论述了赫兹发现了电磁波以及证实电磁波与光波的同一性的全过程,说明赫兹能够证实电磁场理论,主要归因于他精湛的实验技能和敏锐的观察力.  相似文献   

3.
用相对论的方法求得了运动媒质中电磁波的群速度和能流密度,进而分析了它们的物理特征,并由此讨论了运动媒质对电磁波的拖曳作用。  相似文献   

4.
过渡金属硫化物(TMDs)由于其独特的结构和电学性质,在电磁波(EMW)吸收领域表现出巨大的优势。在过去的三年中,人们对基于过渡金属硫化物的电磁波吸收材料进行了大量的研究,但截至目前为止,此领域全面而系统的文献综述仍然较少。研究过渡金属硫化物基吸波材料的形貌结构、相、组分和电磁波吸收性能之间的相互联系具有重要意义。本综述致力于从以下角度分析研究过渡金属硫化物基电磁波吸收材料:TMDs的吸波特性调节策略以及基于TMDs的杂化电磁波吸收材料的最新进展。此外,本文还总结了这些代表性进展的电磁波吸收机理和组分-性能依赖关系。最后,对目前这一领域存在的问题及发展前景进行了探讨。  相似文献   

5.
本文是把从大电流矩形母线的四周往导体内传播的电磁波,近似地看成平面电磁波.其中一对 平面电磁波从母线的左右两侧往内传播,另一对平面电磁波,则由上下两侧面往内传播.两对平 面电磁波中的电波在导体内相叠加的结果,能得到合成的电场强度沿着矩形母线截面的分布,因 而就能找到电流密度的分布规律.  相似文献   

6.
通过对两列对称于Z轴方面传播的均匀平面电磁波迭加后的合成电磁波的分析。得出在两块平行导板之间,由于两导板壁对平面电磁波连续反射结果形成了TE型电磁波,并指出TE型电磁波的能量是沿波导长度力向传播的。  相似文献   

7.
从理论上分析了电磁波在介电常数和磁导率同时为负数的媒质中的传播特点。详细讨论了电磁波以垂直入射和斜入射两种方式照射到不同媒质的分界面时,电磁波的传播规律,介绍了右手物质和左手物质的分界面对电磁波传播的影响,并与两种右手物质的分界面对电磁波传播的影响进行了比较。  相似文献   

8.
甚低频电磁波穿透地层无线通信系统若干问题的探讨   总被引:6,自引:0,他引:6  
从电磁波的经典理论Maxwell方程出发,根据甚低频电磁波在地层中的传播特点,提出实现甚低频电磁波穿透地层无线电通信系统模式,并对其中的若干重要问题进行分析探讨。  相似文献   

9.
金属纤维复合材料的电磁波吸收特性的研究   总被引:3,自引:0,他引:3  
将金属纤维混入混凝土,制成金属纤维复合材料混凝土,与普通混凝土进行电磁波吸纳比较试验,证实金属纤维复合材料有良好的吸收电磁波特性。利用该特性,金属纤维复合材料可用作国防工业和民用工业的电磁波屏蔽材料。  相似文献   

10.
1.癫痫病患者:手机使用者大脑周围产生的电磁波是空间电磁波的4—6倍,少数劣质手机产生的电磁波超过空间电磁波百倍,可使脑电图异常,有诱发癫痫病的可能。 2.严重神经衰弱者:经常使用手机的人可能引发失眠、健忘、多梦、头晕、头痛、烦躁易怒等神经衰弱症状,严重的甚至会导致心理障碍。 3.白内障患者:手机发射出的电磁波可使眼球晶状体温度上升、水肿,加重白内障患者的病情。 4.心脏病患者:心脏功能正常是与钾、钠、钙、镁离子产生的电位平衡分不开的,外来的电磁波可严重干扰心肌电生理过程。试验证明,手机的电磁波可…  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

20.
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