【作者】 魏永杰；

【导师】 葛宝臻；

【作者基本信息】 天津大学 ， 光学工程， 2007， 博士

【摘要】 随着科学技术的飞速发展,颗粒尺寸大小与产品质量、能耗、环境污染等众多领域的关系日益密切,作用越来越重要。因此,准确测量颗粒尺寸的测量意义重大,激光粒度仪以准确度高、重复性好、测量范围宽的优势,在粒度测量领域占有重要地位。本文在分析国内外现状的基础上,围绕激光粒度测试技术开展研究。在理论研究、关键技术和样机研制方面进行了大量工作,取得了预期效果。本文工作的主要创新点如下:1.提出将组合频谱技术应用于粒度测试的理论,根据该理论提出共轴双探测面的激光粒度测试方法,从而扩大了激光粒度测试的量程和动态范围。2.基于最优化问题的目标函数构造方法,提出改进共轭梯度算法的无模式数据处理算法,对参数的选取方法进行了研究和讨论,用于求解单峰或多峰的粒度分布,从而提高仪器的精度和分辨率。3.提出用灰色预测方法修正透镜的渐晕影响,在样品距透镜较远时可以修正测量时的渐晕信号。4.基于组合频谱技术,研制了两种新型激光粒度仪。包括关键器件硅光电探测器组的研制,以及组合光学系统、信号采集系统和机械系统的研制,通过多元硅光电探测器的不同组合和光路系统的不同布置,可满足0.2 ~ 2000μm和5 ~ 3500μm范围的粒度测量。通过对标准物质的测量实验,验证了所提出理论的正确性和所研制的粒度仪样机的有效性。更多还原

【Abstract】 Science and technologies are developing rapidly and there are more connections with particles size in many areas. Particle diameters can influence products qualities, energy consumption, pollution, etc. So it is important to measure particle size exactly. The laser particle sizer has advantages of high repeatability, accuracy, and broad measurable range. It is a kind of leading instruments in the particle size measurement area.The history and recent developments of the theories and technologies of particle size measurements are expatiated. This dissertation is focused on laser particle size measurement technologies. A lot of work was done in theories, key technologies, and research and development of sizer prototypes. Finally, the expected results are attained.The following are the main innovations.1. The combined spectrum technology in laser particle size measurement is presented. Two laser particle size measurement methods are then proposed, where signals are detected on two coaxial focal planes. As a result, the measurable size ranges and the dynamic ranges are extended.2. The improved conjugate gradient algorithm is proposed. The algorithm is based on the objective functions of the optimization algorithm. By adequately selecting the key parameters, it can be used to invert unimodal and multimodal particle size distributions. Simultaneity, the accuracy, the repeatability and the resolving of the sizers are enhanced.3. The grey-prediction theory is used to amend the vignette effect of the lens. The vignetted optical signals can be modified. The problem often appears when the sample is much far away from the lens.4. According to the combined spectrum technology, two new laser particle sizers are developed. The joint Si-photoelectric detectors are developed, they are the key part of the sizers. The combined optical lenses systems, the circuit board, and the mechanical systems are designed. In the optical systems, the particulate sample can be set on different positions, and the detectors are selected and jointed according to the optical systems. Therefore, the particle size in the ranges of 0.2 ~ 2000μm and 5 ~ 3500μm can be measured by the two sizers respectively. Experimental results on standarded particulate samples shows that the presented theories are corrected and the prototypes of the sizers are effective.更多还原