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NONLINEAR RELAXATION SPECTROSCOPY USING A WHITE NOISE INPUT

使用白噪声输入的非线性弛豫光谱

基本信息

批准号：
08455043
负责人：
HAYAKAWA Reinosuke
金额：
$ 4.67万
依托单位：
THE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

As a response to external force easily becomes nonlinear one in soft materials such as polymers and liquid crystal, the nonlinear relaxation spectroscopy is an useful method to investigate the dynamics of these materials. We have already developed the nonlinear dielectric relaxation spectroscopy in a frequency domain using a sinusoidal electric field as an input. But we have to repeat measurements to obtain a whole spectrum changing frequency and amplitude of an input signal.In this rresearch, we developed the measurement system of linear and nonlinear relaxation spectra using a pseudo white noise signal as an input, which is based on the nonlinear response theory of R.Wiener. We can obtain a whole nonlinear spectrum in a wide frequency range at the same time by this system. We applied this system to the nonlinear circuit made of an ideal diode and a low pass filter, and to a ferroelectric liquid crystal cell. We succeeded to measure the linear and nonlinear spectra of the nonlinear circuit in a short time. But we cannot obtain adequate nonlinear spectra for the liquid crystal sample due to the lack of the resolution of A/D converter in the FFT analyzer we used.We also developed the nonlinear electrooptical relaxation spectroscopy and applied this method to ferroelectric and antiferroelectric liquid crystals. We succeeded to obtain new information concerning to the dynamics of these material.In conclusion, we developed new nonlinear relaxation spectroscopies and showed the usefulness of these methods ini the study of dynamics of soft materials.

由于聚合物、液晶等软质材料对外力的响应很容易变为非线性响应，非线性弛豫谱是研究这些材料动力学行为的有效方法。我们已经开发了非线性介电弛豫谱在频域中使用正弦电场作为输入。本文以R. Wiener的非线性响应理论为基础，以伪白色噪声信号为输入信号，研制了线性和非线性弛豫谱测量系统。利用该系统可以在较宽的频率范围内同时获得完整的非线性谱。我们将此系统应用于由理想二极管和低通滤波器组成的非线性电路和铁电液晶盒。我们成功地在短时间内测量了非线性电路的线性和非线性谱。但由于我们所用的FFT分析仪的A/D转换器分辨率不够，不能得到足够的液晶样品的非线性谱，我们又发展了非线性电光弛豫谱，并将这种方法应用于铁电和反铁电液晶。我们成功地获得了有关这些材料动力学的新信息，总之，我们发展了新的非线性弛豫谱，并显示了这些方法在软材料动力学研究中的有用性。