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July 21 String Theory A very good program from pbs.org: http://www.pbs.org/wgbh/nova/elegant/program.html From the Newton gravity to Einstein's general relativity, to the origin of the string theory, to the M-theory, it gives a good picture on how the theory was developed. July 14 转载 "MIT shows China quake was rare event" From: David Chandler,
MIT News Office, June 30, 2008 "A new analysis of the setting for last month's devastating earthquake in China by a team of geoscientists at MIT shows that the quake resulted from faults with little seismic activity, and that similar events in that area occur only once in every 2,000 to 10,000 years, on average. However, the researchers caution that because earthquakes can sometimes occur in clusters, people should still be wary of another possible large-scale earthquake. The magnitude 7.9 quake struck Sichuan province on May 12 at around noontime, which may have increased the human death toll because many people were at school, and the school buildings turned out to be especially vulnerable to collapse because of poor construction. More than 69,000 people have been confirmed dead so far, and more than 374,000 injured, with fears of further casualties because several lakes created by rockfall dams may give way and cause sudden flooding. Clark Burchfiel,
Schlumberger Professor of Geology, and Leigh Royden, professor of
geology and geophysics in the Department of Earth, Atmospheric and
Planetary Sciences at MIT, have been doing extensive research in that
region of China and the Tibetan plateau for more than two decades, but
had found no hints that suggested such a large earthquake might strike
the area. They and several colleagues, including MIT's Robert D. van
der Hilst and Bradford H. Hager, who are both Cecil and Ida Green
Professors of Earth Sciences, have published a paper analyzing the
causes of the quake that appears in the July issue of GSA Today, a
publication of the Geological Society of America. The region is extremely unusual geologically, Royden says, because of the very steep slopes at the boundary between the Sichuan Basin to the east and the Tibetan plateau to the west. The elevation rises sharply by about 3,500 meters (more than two miles) over a span of only about 50 kilometers (about 30 miles). The area where the quake occurred is part of the boundary between two of the Earth's tectonic plates, where the Indian and Asian plates converge in an ongoing collision that has created the Himalayan mountains and the Tibetan plateau. But in central and eastern Tibet, unlike most other areas of continental collision, much of the movement of crust is hidden from view. Instead of thickening the entire crust by folding and faulting, the surface of the eastern Tibetan plateau is undeformed and is being lifted upward by thickening of a weak crustal layer more than 15 km below the surface. The crust in this deep weak layer is flowing eastward away from central Tibet to escape from the area directly north of the Indian plate. But, in the area where the earthquake occurred, this rapidly flowing material is obstructed by a major obstacle, the Sichuan Basin. "The crust and mantle beneath the basin appears to form a hard, cold knot" that extends to 250 km depth, Royden says, that forces the flow to "wrap around the knot." The huge elevation difference between the surface of the plateau and the Sichuan Basin provides the underlying stress that led to the quake, she says. As the surface of the eastern plateau has risen, it has become increasingly incised by rivers. Four of the world's 10 largest rivers, including the Yangtze, flow through the region, Royden says. "There are gorges two and a half to three kilometers deep, and hundreds of kilometers long--they dwarf the Grand Canyon," she says. The steep slopes within the river gorges make the region especially vulnerable when earthquakes occur, she says. "When you shake those valleys, everything just slides down into the river gorges and eventually washes out to sea," she says. Because of the extreme geological environment of this region, Royden says, it may be possible to learn about mechanisms taking place there that may also occur, at a smaller scale, in other places. In this way, it may reveal processes that are also relevant in other parts of the world but that would be much harder to discover in these other locations because they would be more subtly expressed. The research was funded by
the National Science Foundation. The MIT scientists are currently
collaborating with geophysicists of the China Seismological Bureau (in
Beijing and Chengdu, Sichuan) on a study of the structure and seismic
hazard of the region." July 13 康哥来Boston这个周末小康从NYC来Boston,对他的“遍历法”搞怕了。所谓遍历法就是遍历每个建筑每个楼层...小康的好奇心很强尤其对校园。原来和别的同学3个小时内便搞定的mit&harvard这回足足用了7~8小时直到两人都走不动为止。然后晚上去看电影,两个晚上看了两场: Hellboy II和Wanted. 个人感觉Hellboy故事内容比较空洞,里面的老怪也都太弱,整个电影平平淡淡就结束了。Wanted比较血腥,但是情节扣人心弦,特技表演匪夷所思,电影的整体拍摄手法也比较独特,虽然里面的很多场景情节不合逻辑,但是看起来还很有趣。
前几天捡到一盘“帝国时代II“, 于是抱着对中学时代的美好回忆(我初二时候最喜爱的游戏)重温了一把,结果很失望,战斗控制太弱智了,一不留神兵就乱跑... July 07 The summer今年暑假待在学校干活,从早到晚fab, 废寝忘食,好伤身体... 吃饭不规律,有些消化不良... 学习疲劳又产生正反馈,周末空闲时间愈加颓废,简直雪上加霜...
读phd辛苦,锻炼身体不容忽视,发现从来没有认真考虑过“为祖国健康工作50年”背后所蕴含的精神。要想实现它那是需要怎样一种积极健康的生活态度!
虽然假期生活乏味,到是见到不少大学同学,先后有duanyao&sunqing夫妇,Ding henzhou和刚刚毕业的Zhu Yuyuan来Boston. 感觉大家都成熟不少。准备找个周末学一下帆船,还能多提供一个游玩项目。
P.S. 前几天对美国航天技术比较着迷,wiki了一遍apollo program,才发现美国人在1969~1972的4年内总共登上月球六次,共12人。分别为 apollo 11, apollo 12, apollo 14, apollo 15, apollo 16, apollo 17. 希望咱们中国人也能早日登上月球
(越发觉得写东西像小学生作文了...) |
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