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991.
992.
主动光学成象系统衬比传递特性及有效作用距离的分析 总被引:3,自引:0,他引:3
从传输介质对照明和成象光束衰减作用(吸收和散射)的分析入手,通过细致的定量分析,得出了主动系统(包括同轴和非同轴两架)成象材比传模型.这些模型都是将系统参数和衬比联系起来的明确的等式,而且还给出了精度较好的简化模型.这些模型可以为定量分析介质对成象的影响和有关系统设计提供有效而方便的理论工具. 相似文献
993.
光学仪器胶粘剂应用现状及进展 总被引:4,自引:0,他引:4
本文是在对国内光学零件加工及光学仪器产品胶粘剂的应用现状与研究动态的调研基础上,结合作者的工作,综合介绍了光学零件加工过程中工艺用粘接材料与工艺材料用树脂结合剂;光学零件、光学分划元件、光学偏振元件、光学塑料元件等的胶合用光学胶;光学仪器产品结构用结构胶及非结构胶;光学仪器产品及部件用密封胶等的应用现状及其进展概况 相似文献
994.
995.
Fluorescence lifetime imaging of oxygen in living cells 总被引:1,自引:0,他引:1
H. C. Gerritsen R. Sanders A. Draaijer C. Ince Y. K. Levine 《Journal of fluorescence》1997,7(1):11-15
The usefulness of the fluorescent probe ruthenium tris(2,2′-dipyridyl) dichloride hydrate (RTDP) for the quantitative imaging
of oxygen in single cells was investigated utilizing fluorescence lifetime imaging. The results indicate that the fluorescence
behavior of RTDP in the presence of oxygen can be described by the Stem-Volmer equation. This shows that fluorescence quenching
by oxygen is a dynamic quenching process. In addition, it was demonstrated that the fluorescence lifetime of RTDP is insensitive
to pH, ion concentration, and cellular contents. This implies that a simple calibration procedure in buffers can be used to
quantify oxygen concentrations within cells. First fluorescence imaging experiments on J774 macrophages show a nonuniform
fluorescence intensity and a uniform fluorescence lifetime image. This indicates that the RTDP is heterogeneously partitioned
throughout the cells, while the oxygen concentration is constant. 相似文献
996.
A. A. Vertiy S. P. Gavrilov 《International Journal of Infrared and Millimeter Waves》1997,18(9):1761-1781
Tomographycal methods of image reconstruction of two-dimensional objects, surfaces or subsurface regions in millimeter wavelengths
band are suggested and considered. Experimental images obtained using antennas and waveguiding lines of different types and
radiation frequencyf≈33÷35GHz are represented. Volumetric dielectric objects and plane-parallel ferrite (or dielectric) plates distributed in
free space or in homogeneous dielectric medium have been taken as objects under investigation.
It is shown that in the frequency band under consideration, the images of investigated objects with characteristic dimensionA≈2λ÷7λ may be obtained by first-order diffraction tomography method (Born, Rytov or high frequency approximation of the first-order
for electromagnetic field). 相似文献
997.
William H. McCuskey Stephen P. Loehr Gerald C. Smidebush Kerry M. Link 《Magnetic resonance imaging》1993,11(8):1223-1226
Mycotic pseudoaneurysms of the ascending aorta are rare cardiovascular lesions that carry the risk of potentially disastrous complications such as aortic rupture or widespread sepsis. Regardless of its location in the arterial system, this lesion carries a high mortality rate. Early diagnosis of mycotic pseudoaneurysm is paramount for optimizing the chances of surgical therapy. While imaging strategies of this lesion have included aortography, echocardiography, and computed tomography, the information gained from each of these individual studies may be acquired in a single MR imaging session. MRI offers the fundamental advantages of noninvasiveness, nonionization, and multiplanar imaging capabilities. Additionally, MRI provides excellent soft tissue contrast, a wide field of view, qualitative and quantitative flow analysis, and an independence of operator expertise or patient body habitus. 相似文献
998.
Optical diffraction tomography (ODT) is applied to reconstruct the cross-sectional, complex refractive index distribution of cylindrical objects. Experimental reconstructions showing noticeable image contrast for refractive index variations of about 0.001, and having a spatial resolution of about 2 μm, are obtained for objects with cross-sectional diameters of about 100 μm. The results demonstrate that ODT can be used for quantitative imaging of semitransparent fibers.Presented at the International Commission of Optics Topical Meeting, Kyoto, 1994. 相似文献
999.
成核剂对聚丙烯熔融行为的影响 总被引:2,自引:1,他引:1
成核剂对聚丙烯熔融行为的影响陈彦徐懋(中国科学院化学研究所高分子物理开放实验室北京100080)关键词成核剂,聚丙烯,平衡熔点聚合物的熔融过程受分子量大小、分子量分布、分子链构型(等规度、分子结构单元的键接序列)、不同的结晶晶型、不同的热历史等... 相似文献
1000.
Jiying Xiang Zhen Wu Ping Zhang Dexiu Huang Gaoshang Wei 《Optics & Laser Technology》1998,30(2):109-112
A disadvantage of using a galvanometer as the horizontal scanner in CSOM and OCT is its nonlinear distortion caused by the rotational inertial. This is inevitable even if a closed loop is equipped. Here, a second closed loop is introduced to provide pixel clocks to reduce the pincushion distortion of the images. A subdivided step motor is employed to be the vertical scanner as the result of price consideration. Nonetheless, the conventional linearity model of the peck torque with a winding current relationship is no longer in agreement with the experiment when the winding current is low, while a parabolic model is more likely to be reasonable. Relational treatment is proposed in the paper. Both methods have proved to be good enough to meet the requirement of a super resolution scanning imaging. 相似文献