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81.
人眼视网膜成像自适应光学系统设计 总被引:3,自引:0,他引:3
设计一套基于液晶空间光调制器的人眼视网膜成像自适应光学系统,以获得高分辨率视网膜图像,并且使该系统实现体积小,功耗低,成本低等优点.采用夏克-哈特曼探测器和基于硅基板上的液晶器件分别作为波前探测器和波前校正器.系统采用双对准光源以主观方式来使人眼对准,近红外光探测成像以减小对人眼的刺激.使人眼对有限距离对焦,以减小离焦对成像的影响,使该系统既可用于正常眼,又可用于近视眼.用ZEMAX软件对系统进行了模拟分析,认为该系统可获得高于3 μm的视网膜分辨率,该系统设计是合理可行的. 相似文献
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设计一套基于液晶空间光调制器的人眼视网膜成像自适应光学系统,以获得高分辨率视网膜图像,并且使该系统实现体积小,功耗低,成本低等优点.采用夏克-哈特曼探测器和基于硅基板上的液晶器件分别作为波前探测器和波前校正器.系统采用双对准光源以主观方式来使人眼对准,近红外光探测成像以减小对人眼的刺激.使人眼对有限距离对焦,以减小离焦对成像的影响,使该系统既可用于正常眼,又可用于近视眼.用ZEMAX软件对系统进行了模拟分析,认为该系统可获得高于3 μm的视网膜分辨率,该系统设计是合理可行的. 相似文献
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向列相液晶$lt;i$gt;n$lt;/i$gt;CB(4-$lt;i$gt;n$lt;/i$gt;-alkyl-4′-cyanobiphenyls, $lt;i$gt;n$lt;/i$gt;=5—8)的旋转黏度及其奇偶效应的分子动力学模拟
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在全原子力场模型的基础上,对向列液晶nCB(4-n-alkyl-4′-cyanobiphenyls, n=5—8)进行了等压等温NPT系综下的分子动力学(MD)模拟.对MD的轨迹分析得到了二阶和四阶序参数以及描述液晶分子翻转运动的取向时间相关函数(TCF),并通过一个近似的单指函数对TCF拟合得到了相关时间.在此基础上,计算了nCB(n=5—8)的旋转扩散系数(Rotational diffusion coefficient, RDC).利用基于统计力学模型的Nemtsov-Zakharov方法和Fialkowski方法,分别计算了它们的旋转黏度系数(rotational viscosity coefficient, RVC),进而分别讨论了RVC,RDC和相关时间的奇偶效应.与文献中的实验结果比较表明,该方法得到了合理的计算结果和一致的奇偶效应.
关键词:
旋转黏度
奇偶效应
分子动力学模拟
向列相液晶 相似文献
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Simulated human eye retina adaptive optics imaging system based on a liquid crystal on silicon device
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In order to obtain a clear image of the retina of model eye, an
adaptive optics system used to correct the wave-front error is
introduced in this paper. The spatial light modulator that we use
here is a liquid crystal on a silicon device instead of a
conversional deformable mirror. A paper with carbon granule is used
to simulate the retina of human eye. The pupil size of the model eye
is adjustable (3--7mm). A Shack-Hartman wave-front sensor is used
to detect the wave-front aberration. With this construction, a value
of peak-to-valley is achieved to be 0.086Λ, where
Λ is wavelength. The modulation transfer functions before
and after corrections are compared. And the resolution of this
system after correction (69lp/m) is very close to the diffraction
limit resolution. The carbon granule on the white paper which has a
size of 4.7μm is seen clearly. The size of the retina cell is
between 4 and 10μm. So this system has an ability to image
the human eye's retina. 相似文献
88.
Kinetics investigations for holographic Bragg gratingbased on polymer dispersed liquid crystal
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This paper investigates the monomer kinetics of polymer dispersed
liquid crystal (PDLC) grating. Fourier transform infrared (FTIR)
spectra are used in the studies of photoreaction kinetics. The
results indicate that there is a relative stable stage arises after
a very short initial stage. Based on FTIR studies, the monomer
diffusion equation is deduced and necessary numerical simulations
are carried out to analyse the monomer conversion which is an
important point to improve phase separation structure of PDLC
grating. Some simulation results have a good agreement with
experimental data. In addition, the effects induced by monomer
diffusion constant $D$ and diffusion--polymerization-ratio rate $R$
are discussed. Results show that monomer conversion can be improved
by increasing value of $D$. Besides, a good equilibrium state
($R=1$) is more beneficial to the diffusion of monomer which is
important in the process of phase separation. 相似文献
89.
制备了系列含氟光敏单体材料, 六氟双酚A双肉桂酸酯(6F-BADE)与含二氟亚甲基结构的肉桂酸酯(FDE-n, n=2, 3, 4). 材料在线性偏振紫外光辐照下均可发生定向光交联反应, 通过红外光谱和凝胶渗透色谱跟踪检测, 表明光交联类型为[2+2]环加成. 单体光聚后形成的取向膜对液晶分子排列效果不同, 6F-BADE取向膜诱导液晶分子垂直排列, FDE-n取向膜诱导液晶分子平行排列. 用原子力显微镜对取向膜表面进行表征, 均未观察到明显的各向异性分布现象. 应用量子力学半经验方法AM1分析发现单体分子极性有较大差异, 认为分子极性的差异是诱导液晶取向不同的主要原因. 相似文献
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