共查询到20条相似文献,搜索用时 940 毫秒
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根据等效颗粒散射模型,运用经典的Mie理论,对生物组织的散射相函数、各向异性因子及散射系数进行了数值计算.计算结果表明:可见光照射生物组织时,各向异性因子、散射系数随等效颗粒直径增大而增大;等效颗粒直径较小时,各向异性因子、散射系数随入射光波长增大而单调减小;随着等效颗粒直径增大,各向异性因子、散射系数随入射光波长变化不再具有单调性.上述计算结果可合理解释公布的实验结果.
关键词:
生物组织
散射
Mie理论
等效颗粒 相似文献
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用离散偶极子近似法,计算了立方粒子随机取向时在几种等效尺度参数下的光散射特性,并与等效球形粒子的光散射特性进行了比较.结果表明:立方粒子和其他非球形粒子与其等效球形粒子光散射特性之间的差别大致相同,说明对于随机取向的非球形粒子的光散射问题,粒子的内在对称性和表面的突变不会带来明显的效果.
关键词: 相似文献
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研究了典型的层状钙钛矿结构超导单晶Sr2RuO4在c方向的磁阻(Δρ/ρ0)(H∥ab,J∥c)的变化.实验发现,磁阻表现出强烈的各向异性,并且随着温度T的降低,磁阻效应越明显;当在平面ab内旋转磁场H的方向时,磁阻成周期性变化;实验表明,磁场沿(110)方向时,出现磁阻的极大值.分别从Sr2RuO4的费米面的各向异性、载流子散射率、c方向能带色散的各向异性等方面来解释这些输运性质.
关键词:
2RuO4')" href="#">Sr2RuO4
磁阻 相似文献
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主要对2种Si2O分子异构体的激发特性进行研究,由计算结果可知,外电场对Si2O分子的激发能,振子强度,跃迁偶极矩及吸收光谱有着显著的影响.无外电场时三角型Si2O(C2v,1A1)分子在可见光区无吸收谱,外电场作用下其在可见光区(407.18—526.93nm)有比较弱的吸收谱.直线型Si-Si-O(C∞v,3Σ-)分子在有无外电场作用时在蓝光和紫光区均有一定的吸收谱,其中比较难得的是在蓝色光区(478.88—488.59nm)呈现较强的吸收谱. 相似文献
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E. Yu. Vorontsova R. M. Grechishkin I. A. Kaplunov A. I. Kolesnikov V. Ya. Molchanov I. V. Talyzin S. A. Tret’yakov 《Optics and Spectroscopy》2008,104(6):886-889
Upon scattering of laser radiation at different wavelengths, three optical effects—rotation of the plane of polarization of linearly polarized light, dependence of the specific rotation on the radiation wavelength, and the dependence of the scattered light intensity on the angle between the scattered and incident beams—are simultaneously observed. The intensity distributions of the scattered laser light at 0.488, 0.531 nm, and 0.633 μm along the optical axis of a thick sample of a TeO2 single crystal are visualized. Based on the patterns obtained, the values of the specific rotation are calculated, and the curve of the optical rotation for the visible range is obtained. 相似文献
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A new effect—light backscattering from exciton Bose-condensate—is considered. This effect is connected with the photoinduced coherent recombination of two excitons in the condensate with the production of two photons with opposite momenta. The effect of two-exciton coherent recombination leads also to the appearance of the second-order coherence in exciton luminescence connected with squeezing between photon states with opposite momenta. The estimations given for Cu2O and GaAs excitons show that the effect of stimulated light backscattering can be detected experimentally. Moreover, in the system of 2D excitons in coupled quantum wells, the effect of stimulated anomalous light transmission must also take place. Anologous effects can also take place in systems of Bose-condensed atoms in excited (but metastable) states. 相似文献
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Mangesh Bhattarai Vineet Bharti Vasant Natarajan Armen Sargsyan David Sarkisyan 《Physics letters. A》2019,383(1):91-96
We study the sign of resonances obtained in electromagnetically induced transparency (EIT). Resonances of both kinds—bright (corresponding to enhanced absorption) and dark (corresponding to reduced absorption)—are obtained when the frequency of a probe beam is scanned. The experimental results, presented earlier, use magnetic sublevels of a hyperfine transition in the D1 line of 87Rb along with a magnetic field of 27 G. The atoms are contained in a vapor cell at room temperature, and with anti-relaxation coating on the walls. A quantitative theoretical model, which reproduces the experimental results quite well, is presented for the first time. The model solves the density matrix of the sublevels involved, and uses two regions—one with both the light and magnetic field, and the second without light and just a magnetic field. This ability to have both bright and dark resonances promises applications in sub- and super-luminal propagation of light. 相似文献
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利用改进的化学气相沉积法制作出纳米级InP薄膜内包层光纤;根据氢原子本征能量模型计算了InP微粒产生量子尺寸效应的相对粒径aB=8313 nm,且由量子尺寸效应计算了不同尺寸粒子的带隙能量以及相对应的光吸收波长;由测试工作系统测试,在906—1044 nm,1080—1491 nm,1524—1596 nm 波段上均有增益;结果表明:当内包层薄膜材料厚度达5—50nm量级时,其能级将发生红移,产生放大性能.
关键词:
纳米包层光纤
量子尺寸效应
光放大 相似文献
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We describe in detail predictions of the QCD string approach for the masses of the heavy—light D, D s , B, and B s mesons, including orbitally and radially excited states. We discuss the role of the proper dynamics of the QCD string in the formation of the spectrum of the heavy—light mesons, with quark self-energy corrections calculated self-consistently in the same picture. We give our predictions in terms of the current quark masses; the string tension—the only dimensional parameter describing the interquark interaction; and the strong coupling constant, which differs for the fine and the hyperfine interactions. The results are compared with the predictions of other models and with the experimental and lattice results. 相似文献
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A. K. Samusev K. B. Samusev M. V. Rybin M. F. Limonov E. Yu. Trofimova D. A. Kurdyukov V. G. Golubev 《Physics of the Solid State》2011,53(5):1056-1061
This paper reports on experimental and theoretical investigations of light diffraction from thin films of synthetic opal. The diffraction patterns have been studied visually and recorded in different scattering geometries with the films illuminated with white unpolarized light. The diffraction pattern obtained with the film illuminated with a light beam along the [111] axis, which is normal to the film surface, has C 6 symmetry and consists of six strong reflections arranged symmetrically with respect to the incident beam. This pattern becomes substantially more complicated when the film is illuminated by white light at an arbitrary angle to the [111] axis. An experimental study of the spectral response and angular relations of the diffraction patterns has established a fairly full pattern of transformation of diffraction reflections obtained under variation of the angle of light incidence on an opal film. The remarkably good matching of experimental and calculated data provides compelling evidence for light diffraction from thin opal films being two-dimensional. 相似文献
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We present Turing pattern selection in a reaction—diffusion epidemic model under zero-flux boundary conditions. The value of this study is twofold. First, it establishes the amplitude equations for the excited modes, which determines the stability of amplitudes towards uniform and inhomogeneous perturbations. Second, it illustrates all five categories of Turing patterns close to the onset of Turing bifurcation via numerical simulations which indicates that the model dynamics exhibits complex pattern replication: on increasing the control parameter v, the sequence “H0 hexagons → H0-hexagon-stripe mixtures → stripes → Hπ-hexagon-stripe mixtures → Hπ hexagons” is observed. This may enrich the pattern dynamics in a diffusive epidemic model. 相似文献
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通过对衬底施加负偏压吸引等离子体中的阳离子对衬底轰击,从而用射频磁控溅射法在水冷透明绦纶聚脂胶片上制备出相对透过率为80%左右、最小电阻率为63×10-4Ωcm、附着良好的ITO(Indium Tin Oxide)透明导电膜.SnO2最佳掺杂浓度为7.5%—10%(w.t.),最佳氩分压为0.5—1Pa.当衬底负偏压为20—40V时,晶粒平均尺寸最大,制备出的薄膜的电阻率有最小值.薄膜为多晶纤锌矿结构,垂直于衬底的c轴具有[222]方向的择优取向,随衬底负偏压
关键词: 相似文献