International Research Fellow Awards: Nonlinear Electrokinetic Effects on the Dynamics of Colloidal Particles

小行星9705810 国际研究员奖励计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。该计划的奖项提供了联合研究的机会，以及使用国外独特或互补的设施，专业知识和实验条件。 该奖项将支持詹姆斯·C博士为期九个月的博士后研究访问。亚利桑那大学的Baymont博士与澳大利亚悉尼大学的Robert J. Hunter博士合作。 美国将为该项目提供支持-国际项目部澳大利亚项目。 这个项目将致力于描述胶体粒子在随位置和时间变化的外加电场中的动力学。 配备一个适当的理论描述的粒子动力学，然后可以解释实验测量的非线性电动效应的结果。 电声学是一种将交变电场施加到胶体悬浮液上的过程。 由于大多数胶体粒子是带电的，它们通过以与所施加的场相同的频率来回振荡来响应该场。 这会产生声波，通过测量声波的特性，可以获得胶体颗粒的详细特征。 目前的理论假设，所施加的场强是如此之低，粒子的响应是线性的。 Baygent博士的研究将扩展这些效应的理论，以考虑到场强提高到更高水平时会产生的非线性效应。 足够高的场应该能够使粒子沿着场的方向取向，这将使它们对未取向的粒子作出不同的响应。 如果颗粒是非球形的，则可以使用该附加信息来获得颗粒的电荷和尺寸以及它们的纵横比（长度与直径）。 ***

9705810 Baygents The International Research Fellow Awards Program enables U.S. scientists and engineers to conduct three to twenty - four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad. This award will support a nine-month postdoctoral research visit by Dr. James C. Baygents of the University of Arizona to work with Dr. Robert J. Hunter at the University of Sydney in Australia. Support for this project will be provided by the U.S.-Australia Program of the Division of International Programs. This project will work to describe the dynamics of colloidal particles in applied electric fields that vary with position and time. Equipped with a proper theoretical description of the particle dynamics, one can then interpret the results of experimental measurements on nonlinear electrokinetic effects. Electroacoustics is a procedure in which one applies an alternating electric field to a colloidal suspension. Since most colloid particles are electrically charged, they respond to this field by oscillating backwards and forwards at the same frequency as the applied field. This generates a sound wave, and it is by measuring the properties of the sound wave that it is possible to obtain a detailed characterization of the colloid particles. Current theory assumes that the applied field strengths are so low that the particle response is linear. Dr. Baygent's research will extend the theories of these effects to take into account the non-linear effects which would result if the field strength is raised to much higher levels. Sufficiently high fields should be able to orient the particles along the direction of the field and this would cause them to respond differently to an unoriented particle. This added information could be used to obtain the charge and size of the particles as well as their aspect ratio (length to diameter) if they are non-spherical. ***