Transport phenomena in microelectronics & metals processing

在微电子和金属加工中的传输现象的总主题下，申请人希望在两个具有直接工业重要性的领域进行基础研究。这些建议涉及：（a）在改进的化学气相沉积（MCVD）反应器中SiO2和GeO 2的共沉积的数学和物理建模，以及（B）颗粒在液体金属和流体中的超声解团聚和分散。(a)MCVD反应器用于商业制造高质量光纤。MCVD反应器由缓慢旋转、火抛光、加热的石英管组成，其中引入气态四氯化硅（SiCl 4）、四氯化锗（GeCl 4）和氧气的混合物。感兴趣的反应产物是存款在管的内表面上的SiO2和GeO 2的细颗粒。在沉积了足够数量的层之后，管被折叠成固体预制棒，然后被拉制成细长纤维。这项工作的第一个目标是开发一个瞬态三维传输模型，该模型将提供温度，速度和浓度分布以及反应器内SiO2和GeO 2的沉积速率。第二个目标是在中国安排的实验研究设施中进行MCVD实验。实验结果将用于验证建模结果，并且将适当调整和/或修改模型以提供令人满意的结果。(b)在金属、制药、化学、油漆和油墨工业的许多工艺中需要粉末的分散和解聚。任何粒度的粉末在混合到液体中时倾向于形成附聚物。因此，需要有效的解团聚和分散手段来克服润湿微米或纳米粉末后的结合力。将建立数学和物理模型来解释流体中细颗粒的超声分散现象。本研究亦将发展一超音波装置以量测气泡之颗粒负载特性，以制造工业上之高效浮选柱

Under the general theme of transport phenomena in microelectronics and metals processing, the applicant wishes to carry out fundamental research in two areas of direct industrial importance. These are concerned with: (a) Mathematical and physical modeling of co-deposition of SiO2 and GeO2 in Modified Chemical Vapor Deposition (MCVD) reactors, and (b) ultrasonic de-agglomeration and dispersion of particles in liquid metals and fluids. (a) MCVD reactors are used to commercially manufacture high quality optical fibers. A MCVD reactor consists of a slowly rotating, fire polished, heated silica tube wherein a mixture of gaseous silicon tetrachloride (SiCl4), germanium tetrachloride (GeCl4) and oxygen is introduced. The reaction products of interest are fine particles of SiO2 and GeO2 which deposit onto the inner surface of the tube. After a sufficient number of layers are deposited, the tube is collapsed into a solid preform rod and then drawn into a long thin fiber. The first objective of this work is to develop a transient 3D transport model which will provide temperature, velocity and concentration profiles as well as deposition rates of SiO2 and GeO2 inside the reactor. The second objective is to perform MCVD experiments in an arranged experimental research facility in China. Experimental results will be used to verify modeling results and the model will be appropriately tuned and/or modify to provide satisfactory results. (b) Dispersion and de-agglomeration of powders are required in many processes in the metals, pharmaceutical, chemical, paint and ink industries. Powder of any particle size tends to form agglomerates when being mixed into a liquid. Therefore, effective means of de-agglomerating and dispersing are required to overcome the bonding forces after wetting the micron- or nano-powders. Mathematical and physical models will be developed to explain the ultrasonic dispersion phenomenon of fine particles in fluids. An ultrasonic device will also be developed to measure bubbles' particles loading characteristics to make efficient flotation columns for industry