共查询到20条相似文献,搜索用时 62 毫秒
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用于高速数据通信的梯度塑料光纤 总被引:1,自引:0,他引:1
概述了梯度塑料光纤的开发历史和现状。从应用于高速数据通信的角度 ,介绍了聚甲基丙烯酸甲酯(PMMA)、全氘化和全氟化梯度塑料光纤的损耗、带宽、稳定性和寿命。详细介绍了梯度塑料光纤的损耗光谱和损耗机制 ,介绍了制作梯度塑料光纤的界面凝胶聚合技术和两种扩散法 ,分析了梯度塑料光纤的制作方法同折射率剖面和带宽的关系 ,讨论了梯度塑料光纤的稳定性同掺杂物质的关系。同时介绍了高稳定性梯度塑料光纤的研究进展及今后的发展动向 相似文献
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采用离子交换法制备了Rb:KTP晶体光波导,在不同波长的耦合光下测量了TE和TM偏振波导模式的有效折射率,拟合了波导层折射率的余误差函数分布,证明了波导折射率增量的各向异性,给出了其色散关系;最后计算并讨论了Rb:KTP波导的扩散特性。 相似文献
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The results of studying the magnetomechanical effects in classical superconductors are analyzed. The energy losses are determined,
and a number of macroscopic parameters are calculated using a developed model. The studies of superconductors by the method
of rotation of a body suspended without contact are described. The results obtained are analyzed, and the values of some parameters
are determined. 相似文献
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We theoretically study the resonant transmission of electromagnetic waves at the THz frequencies through subwavelength semiconductor
slits under external static magnetic fields. The dispersion relations of the surface plasmon polaritons (SPPs) inside a subwavelength
slit are analytically derived. It is found that the SPPs propagating along one direction and its reverse are symmetric when
parallel external magnetic fields are applied, but are asymmetric when antiparallel external magnetic fields are applied.
The transmission properties of periodic subwavelength semiconductor slit arrays with the antiparallel magnetic fields in each
unit cell are investigated by the mode expansion technique. The two significant transmission characteristics are observed:
(i) The resonant peaks are redshifted with increasing external magnetic fields; (ii) The transmissions in the two opposite
directions through the slit arrays are asymmetric. The origin of the transmission asymmetry is reasonably explained by the
magnetic-field induced asymmetric SPP propagation losses. 相似文献
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单轴晶光轴干涉图成因的理论分析 总被引:1,自引:0,他引:1
借助于数学工具和一种简单的实验装置,用直观的方法,使理论分析和图形相结合,从理论上解释了单轴晶光轴干涉图的成因,并给出了在白光照射下的干涉花样。搭建了实验光路,结果表明:若用单色光照射,干涉图为明暗相间圆环;若用白光照射,则为一个套一个的环状等色曲线。愈向视域边缘,干涉色级数愈高,等色曲线的数目愈多,密度愈大,表示晶体的双折射率愈大。实验结果与理论分析相吻合。 相似文献
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亲水性材料固相萃取-紫外导数光谱法检测血中茚满二酮灯抗凝 … 总被引:6,自引:1,他引:5
本文报导了血中茚满二酮类抗凝血杀鼠剂敌鼠、氯敌鼠、杀鼠酮的亲水性材料固相萃取-紫外导数光谱检测法。血样用pH5缓冲液等体积稀释后加于西雷脱硅藻土柱上,柱用乙酸乙 酯洗脱,将洗脱液挥发干净,剩余物用pH10缓冲液溶解,测定所得溶液的二阶导数光谱进行定性和定量分析。三种杀鼠剂以10mg/L的量加于空白血中测得萃取率为85%以上,血中三种杀鼠剂的检出限低于2mg/L。萃取中亲水性硅藻土可用硅胶和氧化铝代替, 相似文献
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The spin-wave excitations in anisotropic Kondo lattice model are studied using the spin Green's function. Both the ferromagnetic and antiferromagnetic cases are considered. The equations to determine the spectrum of low-energy excitations are given. The anisotropy gaps are obtained, and the long-wavelength and strong-coupling limits are analyzed. 相似文献
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超光谱成像仪红外系统热控技术研究 总被引:2,自引:1,他引:1
介绍了超光谱成像仪红外系统的应用价值,总结了红外系统在光学元件、焦平面器件、光机结构等不同部分的热控需求。通过主动热控与被动热控的比较,阐述了超光谱成像仪红外系统热控策略,并且归纳了适合其要求的热控技术。其中针对红外系统焦平面热控,对辐射制冷和机械制冷进行了比较,并简要介绍了斯特林制冷机。最后总结了目前超光谱成像仪红外系统热控的关键问题。 相似文献
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Rodney Loudon 《物理学进展》2013,62(66):243-280
The contributions of magnons to the optical properties of antiferromagnets having the rutile structure are discussed. The properties considered are electric-dipole active two-magnon absorption in the infra-red, and magnon sidebands on sharp-line exciton transitions in the visible. The discussion is based on a thorough treatment of the properties of excitons and magnons in the antiferromagnetically ordered state. The site-group and space-group symmetries of the magnetic excitations are derived and the selection rules for electric and magnetic dipole transitions are determined. The occurrence of magnetic Davydov splittings of the excitons is investigated, and their symmetry properties throughout the Brillouin zone are derived. The functional dependences of exciton energy on wave vector are calculated. Applications of the theory are made to experimental results on excitons and magnons in MnF2, FeF2 and CoF2. The possible mechanisms for two-magnon and magnon-sideband absorption are discussed, and the influence of crystal symmetry on these mechanisms is described. The two-magnon state responsible for electric-dipole absorption is identified and selection rules for electric-dipole activity are presented. A spin Hamiltonian for the two-magnon process is set up and used to derive expressions for absorption coefficients for electric vector parallel and perpendicular to the crystal c-axis. Comparison with experiment for MnF2 yields numerical values for the parameters of the basic coupling mechanism. The exciton-magnon states which give rise to magnon-sideband absorption are explicitly constructed and electric-dipole selection rules are derived for all possible types of sideband. Spin Hamiltonians for the various magnonsideband absorption processes are presented and used to derive expressions for sideband shapes. The results are applied to the experimental spectra for MnF2 and FeF2 and the sideband shapes in MnF2 are calculated numerically. The sideband shapes observable in emission spectra are also briefly discussed. 相似文献
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针对二维光场信息的测试需求,分析了无穷远物面二维特征点信息检测中应注意的问题。介绍了平行光管物镜的设计,给出了物镜的像差计算结果;介绍了分划板的设计和特征点信息提取方法;介绍了激光场信息测试系统的结构和原理,并给出了实测结果。 相似文献
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Nimrod Moiseyev Romanas Narevich 《International Journal of Theoretical Physics》2003,42(10):2131-2143
Resonances are defined as the poles of the scattering matrix. The poles are associated with the complex eigenvalues of the Hamiltonian which are embedded in the lower half of the complex plane. The asymptotes of the corresponding eigenfunctions are exponentially diverged. Therefore, the resonance eigenfunctions are not embedded in the Hermitian domain of the Hamiltonian. The time asymmetric problem is discussed for these types of non-Hermitian Hamiltonians and several solutions of this problem are proposed. 相似文献
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A.-S. F. Obada G. M. Abd Al-Kader 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(1):189-198
The nonlinear extensions of the single-mode squeezed vacuum and
squeezed coherent states are studied. We have constructed the
nonlinear squeezed states (NLSS's) realization of
SU(1,1) Lie algebra. Two cases of this realization are
considered for unitary and non-unitary deformation operator
function. The nonlinear squeezed coherent states (NLSCS's)
are defined and special cases of these states are obtained.
Some nonclassical properties of these states are discussed. The
s-parameterized characteristic function and various moments are
calculated. The Glauber second-order coherence function is
calculated. The squeezing properties of the NLSCS's are studied.
Analytical and numerical results for the quadrature component
distributions for the NLSCS's are presented. A generation scheme for
NLSCS's using the trapped ions centre-of-mass motion approach is
proposed. 相似文献