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激光在大气传输过程中,由于同大气分子与气溶胶粒子之间的相互作用而产生了一系列的效应,即大气衰减和大气湍流效应,导致能量不断减弱,并影响激光的远场能量密度分布.根据设计的激光远场能量密度分布测试系统进行外场实际试验测试,只能获得指定位置上的远场能量密度分布数据和激光光斑图像,为了获得任意位置的激光传输特性,研究了大气衰减和大气湍流对激光传输的影响.根据上述系统测得的指定位置的光斑图像及能量分布数据,通过软件仿真分析,估算任意位置的激光光斑能量密度分布,通过伪彩色变换,将激光光斑的灰度图像转换为连续变化的伪彩色图像,可以直观地观察光斑的远场能量密度分布. 相似文献
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针对传统方法求解全柔顺并联机构Jacobian矩阵存在奇异性的缺陷,基于三自由度平面全柔顺并联机构的伪刚体模型,提出一种微位移法来求解机构的Jacobian矩阵。先建立机构的伪刚体模型,并采用传统方法和微位移法得到机构的输入输出Jacobian矩阵;通过HyperMesh软件仿真和实验测试分别得到机构动平台中心点位移的仿真值和实验值。最后,将两种方法得到的理论值分别与仿真值、实验值进行对比。对比结果表明:与传统法相比,微位移法的计算精度较高,误差较小,且验证了Jacobian矩阵的有效性,为全柔顺并联机构的运动特性分析提供了参考。 相似文献
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An extrinsic fibre Fabry-Pérot interferometric (EFFPI) sensor for the measurement of velocity and displacement of a vibrating target has been demonstrated in this work. It operates on the principle of a pseudo-double cavity within a single interferometric or “sensing” arm which, in addition, provides a sense of direction of the moving target. This has been made possible by the introduction of a birefringent film positioned along the optical path between the sensing fibre end and the intended target. Two sets of interference signals are thus propagated and detected along one fibre arm to give robust and repeatable displacement–velocity information which have been found to be relatively independent on other external effects such as minor temperature changes. The sensor has been found to be capable of measuring the desired velocity information of an inclined target while typical excitation frequencies investigated ranged from 2 to 60 Hz. In addition, two sensor configurations have been studied, one based on “conventional” optical fibres at 780 nm while the other employs a polarisation-maintaining (PM) (PANDA type) fibre as the sensing arm and operates at 1310 nm. 相似文献
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序列图像拼接过程中误匹配的消除 总被引:2,自引:0,他引:2
序列图像拼接过程中困难之一是当重叠区域内存在多个相似部分时,就会发生误区配而导致拼接失败。在采用图像特征区域配准算法中,基于同名区域面积差、区域重心同位、区域重心距离比及配准参数复用提出了四种误区配的消除方法。实验表明,这些方法能有效地消除误匹配,提高序列图像拼接的配准率。 相似文献
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Oleogels from Glycerol‐Based Lyotropic Liquid Crystals: Phase Diagrams and Structural Characterization 下载免费PDF全文
Yael Cegla‐Nemirovsky Abraham Aserin Nissim Garti 《Journal of the American Oil Chemists' Society》2015,92(3):439-447
In the course of our studies on structured reverse lyotropic liquid crystals (LLC) as oleogels, a system was designed with the desired physical and rheology properties for cosmetic and pharmaceutical applications. The aqueous phase was partially replaced by glycerol to minimize bacteriological problems and obtain specific rheology characteristics. The constructed phase diagrams are based on ternary mixtures of glycerol monooleate (GMO), decane, water, and glycerol. The main lyotropic mesophase obtained in this study was reverse hexagonal derived from dilution line 8:2 (72 wt% GMO and 18 wt% decane) and 10 wt% water; or water:glycerol (wt ratios 3:1 and 1:1) mixture. It was found that heat‐cool fluctuation caused formation of new pseudo‐equilibrium structures with mesomorphic transformations to more fluid and less ordered mesostructures. Replacing up to 50 wt% of the water by glycerol significantly increases the gel phase region in the phase diagram, meaning more structural compositional options. The structural parameters were determined using cross‐polarized light microscopy (CPLM), differential scanning calorimeter (DSC), powder X‐ray diffraction (PXRD), and small angle X‐ray scattering (SAXS). Rheological measurements revealed viscoelastic properties of lyotropic liquid crystals with a decrease in the elasticity (G′), plasticity (G″), and complex viscosity (η*), as a function of increasing the glycerol content. 相似文献
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Tuning of Cloud Point by the Nature of Surfactant Headgroup: Influence of Counterion and Additives 下载免费PDF全文
Sanjay Kumar Yadav Ran Bahadur Yadav Sanjeev Kumar 《Journal of surfactants and detergents》2016,19(5):1063-1069
Work was performed to distinguish the role of sulfonate (–SO3 ?) and sulfate (–OSO3 ?) with respect to the micellization and clouding phenomenon in ionic surfactant solutions. The clouding phenomenon is a recent addition to the conventional one observed with nonionic surfactants. Three ionic surfactants [sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and sodium dodecylsulfonate (SDSo)] are chosen and the effects of added tetra-n-pentylammonium bromide (TPeAB) and benzyl tributylammonium bromide (BTAC) have been studied on micellization and clouding behaviors in aqueous solution. Based on critical micelle concentration (CMC) and cloud point (CP) measurements, the following order has been observed: SDBS < SDS < SDSo. Though both SDBS and SDSo contain sulfonate groups, they are found at the two ends of the ordering. Therefore, the role of the phenyl ring is also having importance in clouding phenomena. For a typical surfactant, TPeAB was found to be more effective than BTAC. Based on the CP studies, two compositions of SDSo + TPeAB/BTAC were chosen and the effects of different additives (carbohydrate, amino acid, and l-ascorbic acid) on the CP were investigated. Additive may either decrease or increase CP, depending on the structure of the counterion or additive. The present work shows a few novelties: (1) headgroup/counterion dependence of CP and (2) hydrophobicity of counterion/surfactant has an important bearing on the phenomenon. The data can be utilised in improving cloud point extraction methodologies (CPEMs). 相似文献