演講者：胡宇光 教授 單　位：中央研究院物理研究所 地 點：理一講堂 時　間：16:10~18:00 專題演講講題： X-ray microscopy using synchrotron light and its application in life sciences 摘要： Radiology is the oldest and by far the largest field of application of x-rays. In recent years, this domain has been literally revolutionized by the exploitation of the unique characteristics of synchrotron sources. The results are particularly spectacular when the high spatial coherence of the radiation is used for novel and powerful approaches to radiology. The results are very high quality microradiology and microtomograhy images and movies - taken with a limited x-ray dose – that find a variety of applications in materials science, biology and medical research. In addition to review a small number of examples obtained from the intensive use of this new approach of microradiology over the past decade, I will also present the first successful use of hard-x-ray microscopy to investigate intracellular structures. This development allows better lateral resolution than optical microscopy and produces 3-dimensional and topographic images of thick biological specimens. The key factors in our success are the use of a coherent synchrotron source in conjunction with a high-resolution phase zone plate x-ray microscope and the exploitation of contrast mechanisms based on the refractive index. In particular, the zone plate magnifies the projected x-rays producing high-quality images of human cells with 60 nm resolution. The high penetration of hard-x-ray was exploited to demonstrate that thick tissue samples can be viewed without decreasing the resolution. A phase retrieval method based on a wave propagation algorithm from a series of defocused images further improved the image quality. 參考網頁 http://ws2-sun.ndhu.edu.tw/students.php 在公告信息區 ies of defocused images further improved the image quality -- ※ Origin: 東方小城 (bbs.ndhu.edu.tw) ◆ From: 134-208-45-230.ndhu.edu.tw