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Development of rho-optical spectroscopy by means of ultrasound difrtaction

通过超声衍射开发rho光学光谱学

基本信息

批准号：
18540404
负责人：
MATSUOKA Tatsuro
金额：
$ 2.57万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

The purpose of this study is to develop an apparatus to measure rheo-optical coefficient in the high frequency range using the ultrasound diffraction phenomena Measurement of the polarization parameters, change in azimuth angle and phase retardation, of first order diffracted light give information of ratio of complex anis: tropic sinusoidal response in the refractive indices to the isotopic response one caused the ultrasound. Here we explain what complex response means. The anisotropic sinusoidal response is in phase to isotropic one phase is called a real response while the sinusoidal response which differs by 90 degree from isotropic one in phase is called imaginary response. We have modified the theory of complex responses using de Gennes' translational-reorientational coupling formula applying to ultrasound dispersion relation. Using this formula, we can compare the experiential results with the theory using the data of flow birefringence and reorientational relaxation time.We car … More ried out the experiment in triphenylphosphite (TPP) and isotropic phase of liquid crystal, 4-cyano-4'-pentylbiphenyl (5CB). The former does not show the frequency dependent response and only imaginary responses are detected. Those are due to the reorientational-relaxation time is much larger that that of ultrasonic frequency. In case of 5CB, not only imaginary but also real responses were observed. Those are due to the reorientational relaxation frequencies are comparable to ultrasonic frequencies (5-25MHz) used in this study. The complex spectra obtained from polarization measurements fairly are good agreement with our modified theory using the values of flow birefringence and reorientational relaxation time.In higher frequencies, the intensity of diffracted light is to be small. So we have to improve the sensitivity of our apparatus. In the studies in 2007, we adapted a photomultiplier as a detection device instead of photodiode. This enables us to measure the low ultrasound intensity measurements and that enable the analysis of polarization parameter quite simple. The measurement can be carried out at the Raman-Nath parameter is about 0.1. This success is promising to the future measurements in higher frequency range Less

本研究的目的是开发一种利用超声衍射现象测量高频范围内的流变光学系数的装置。测量一阶衍射光的偏振参数、方位角的变化和相位延迟，给出复数茴香之比的信息：折射率中的热带正弦响应与引起超声的同位素响应。在这里我们解释复杂响应的含义。各向异性正弦响应与各向同性单相同相的正弦响应称为实响应，而与各向同性同相相差 90 度的正弦响应称为虚响应。我们使用适用于超声色散关系的 de Gennes 平移重定向耦合公式修改了复杂响应理论。利用这个公式，我们可以利用流动双折射和重定向弛豫时间的数据将经验结果与理论进行比较。我们在亚磷酸三苯酯（TPP）和液晶各向同性相4-氰基-4'-戊基联苯（5CB）中进行了实验。前者不显示频率相关响应，仅检测到虚响应。这是由于重定向弛豫时间远大于超声频率的时间。对于 5CB，不仅观察到了想象的响应，还观察到了真实的响应。这是因为重定向弛豫频率与本研究中使用的超声波频率 (5-25MHz) 相当。从偏振测量中获得的复杂光谱与我们使用流动双折射和重定向弛豫时间的值的修改理论相当吻合。在较高频率下，衍射光的强度较小。所以我们必须提高仪器的灵敏度。在2007年的研究中，我们采用光电倍增管代替光电二极管作为检测装置。这使我们能够测量低超声强度，并且使偏振参数的分析变得非常简单。可以在Raman-Nath参数约为0.1时进行测量。这一成功为未来更高频率范围的测量带来了希望。