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Feding Ge Jing Zhu Limin Chen 《International Journal of Infrared and Millimeter Waves》1996,17(2):449-455
The effective parameters of chiral composite are studied using a simple model, that is, randomly oriented non-interacting wire helices embedded in a nonchiral host medium. It is found that both the effective permittivity and permeability are independent on the handedness of the chiral objects while the effective chirality admittance is dependent. It is also found that when the ratio of the radius of the chiral helix to its pitch is about 0.23, maximum chirality admittance is achieved. The effective parameters of equichiral sample are also discussed. 相似文献
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Renormalization of one-pion exchange in higher partial waves in chiral effective field theory for antinucleon-nucleon system
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Daren Zhou 《中国物理C(英文版)》2023,47(3):034103-034103-15
The renormalization of the iterated one-pion exchange (OPE) has been studied in chiral effective field theory (χEFT) for the antinucleon-nucleon (begin{document}$ overline{N} N $end{document} ![]()
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) scattering in some partial waves (Phys. Rev. C 105, 054005 (2022)). In this paper, we go further for the other higher partial waves but with total angular momenta begin{document}$ Jleq 3 $end{document} ![]()
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. Contact interactions are represented by a complex spherical well in the coordinate space. Changing the radius of the spherical well means changing the cutoff. We check the cutoff dependence of the phase shifts, inelasticities, and mixing angles for the partial waves and show that contact interactions are needed at leading order in channels where the singular tensor potentials of OPE are attractive. The results are compared with the energy-dependent partial-wave analysis of begin{document}$ overline{N} N $end{document} ![]()
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scattering data. Comparisons between our conclusions and applications of χEFT to the nucleon-nucleon system are also discussed. 相似文献
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Funding Ge Limin Chen Jing Zhu 《International Journal of Infrared and Millimeter Waves》1996,17(1):255-268
The formulations of reflection coefficients for metal-backed one- and multi-layered chiral microwave absorbing coatings are derived in a much straight way in this paper. It is found that the propagation of normally incident plane waves in chiral coatings can be treated as in their achiral counterparts if the intrinsic impedance and wavenumber of the achiral structure are replaced by their associated chiral impedance and average chiral wavenumber, respectively. From a practical point of view, examples of one- and two-layered chiral microwave absorbing coatings are given, and the effects of the real and imaginary parts of the chiral admittance on the antireflection characteristics are examined for the first time, the results show that with a appropriate complex chiral admittance, the reduction in reflection can be enhanced and the minimum-reflection-frequency can be controlled. 相似文献
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在旋波介质研究过程中,人们提出了多种形式的物质方程.由于表达形式和使用符号的不同,很容易造成误解和混淆.本文对常用的4种物质方程形式进行了推导和整理,给出了它们之间的对应关系. 相似文献
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针对航空激光防护技术研究需求,开展了复合涂层材料的激光烧蚀效应综合研究。采用圆棒固体激光器作为测试光源,搭建了具有在线温度测量功能的烧蚀实验平台。在此基础上,对聚碳硅烷(PCS)涂层样品开展了激光烧蚀实验。通过对烧蚀区域形貌和温度数据的对比分析,证明了PCS复合材料具备显著的激光防护作用。同时,从理论方面对涂层的激光防护机理进行了研究,基于材料热传导方程,建立了激光烧蚀过程的热力学模型,对温度场变化进行了模拟。研究结果表明,在复合涂层的保护下,kW级激光仅产生百℃的金属基底升温。 相似文献
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利用谱表示理论和微扰展开法,从理论上给出了适合于一般微结构复合体系的有效非线性响 应的一般表示式,并结合有效媒质近似(EMA),在弱非线性条件下研究了由三阶非线性组 分(体积分数为p)和线性组分构成的非线性复合体系的有效非线性响应,讨论了复合 体系的有效介电常数ε~e=εe+χe|E0|2+ηe|E0| 4中的有效三次非线性响应χe和有效高次非线性响应ηe与体积分数p和 退极化因子L之间的关系,分析了非线性组分的介电常数为复数情形时体系的有效高阶非线 性响应,从理论上说明了组分的高次非线性响应对整个复合体系的有效介电常数的影响.
关键词:
非线性复合介质
有效非线性响应
谱表示理论 相似文献
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A simple method was proposed to prepare nanosized Si composite anode materials for lithium-ion (Li-ion) batteries. The preparation
started with the shock-type ball milling of silicon in liquid media of polyacrylonitrile (PAN)/dimethylformamide (DMF) solution,
forming slurry where the nano-Si particles were uniformly dispersed, followed by the drying of the slurry to remove DMF. The
nanosized Si composite anode material was obtained after the pyrolysis of the mixture at 300 °C where the pyrolyzed PAN provided
a conductive matrix to relieve the morphological change of Si during cycling. As-prepared composite presented good cyclability
for lithium storage. The proposed process paves an effective way to prepare high performance Si, Sn, Sb and their alloys based
composite anode materials for Li-ion batteries. 相似文献
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We derive the chiral effective Lagrangian for excited heavy-light mesons from QCD under proper approximations. We focus on the chiral partners with j_l~P=3+/2 and j_l~P=3~-/2 which amounts to(1~+, 2~+) and(1~-, 2~-) states respectively. The low energy constants including the masses of the chiral partners are calculated. The calculated spectrum for the excited mesons are found roughly consistent with experimental data. In addition, our results indicate that quantum numbers of B_J(5970) can be identified with 1~-or 2~-. 相似文献
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Some nontrivial effects (negative refraction and quantum vacuum effects) in gyroelectric chiral medium and magnetoelectric material are studied. It is shown that the refractive indices corresponding to some of the eigen modes in the gyroelectric chiral medium and magnetoelectric material may have negative real parts since both the gyroelectric and magnetoelectric parameters can dramatically reduce the refractive indices in certain frequency bands. As an anisotropic electromagnetic environment could be created due to the breaking of universal symmetry of vacuum mode distribution (and hence the noncompensation effect of a pair of counter‐propagating vacuum modes arises) inside the magnetoelectric material, the quantum vacuum in such an anisotropic electromagnetic environment may have a nonzero angular momentum. A novel quantum vacuum effect (angular momentum transfer between the quantum vacuum and the anisotropic magnetoelectric material) that may accompany the effect of magnetoelectric negative refraction is suggested. Such a nontrivial effect can be utilized to design sensitive, accurate measurement techniques, e.g., nanoscale‐sensitivity sensor. 相似文献
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Based on a filler of plant origin, we have developed a new composite material and have studied its spectral and polarization
properties. We suggest a direction for application of the synthesized material.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 419–421, May–June, 2008. 相似文献
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对于电小厚度的平面分层介质,在电磁波垂直入射情况下,根据边界条件把中间层介质等效为一层得到了有效介电常量和有效磁导率的表达式,为分析电磁波在多层介质中的传播问题提供了一种有效方法. 相似文献
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In this work,we study the renormalization group invariance of the recently proposed covariant power counting in the case of nucleon-nucleon scattering [Chin.Phys.C 42(2018) 014103] at leading order.We show that unlike the Weinberg scheme,renormalizaion group invariance is satisfied in the ~3 P_0 channel.Another interesting feature is that the ~1 S_0 and ~3 P_1 channels are correlated.Fixing the relevant low energy constants by fitting to the ~1 S_O phase shifts at T_(lab).=10 and 25 MeV with cutoff values ∧=400-650 MeV,one can describe the ~3 p_1 phase shifts relatively well.In the limit of ∧→∞,the ~1 S_0 phase shifts become cutoff-independent,whereas the ~3 P_1 phase shifts do not.This is consistent with the Wigner bound and previous observations that the ~3 P_1 channel is best treated perturbatively.As for the ~1 P_1 and ~3 S_1-~3 D_1 channels,renormalization group invariance is satisfied. 相似文献