首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   19篇
  免费   0篇
化学   11篇
力学   1篇
数学   4篇
物理学   3篇
  2019年   1篇
  2016年   1篇
  2014年   1篇
  2013年   2篇
  2012年   1篇
  2009年   1篇
  2008年   1篇
  2003年   1篇
  2002年   1篇
  1981年   2篇
  1977年   1篇
  1964年   1篇
  1958年   1篇
  1928年   2篇
  1902年   1篇
  1895年   1篇
排序方式: 共有19条查询结果,搜索用时 62 毫秒
1.
2.
The work is dedicated to one of the systems of the NESTOR X-ray generator. The injection system is at the highest stage of readiness after the magnetic system. Structurally, the injection system can be represented as an injector (linear accelerator), channel of parallel transportation (transport channel), channel of the beam entry into the vacuum chamber, and pulsed inflector. All equipment has been tested, and the beam passed through all the components in the volume of the storage ring.  相似文献   
3.
The C1-C6 segment of a number of 14-membered macrolide antibiotics have been synthesized started from levoglucosan.  相似文献   
4.
The C9-C13 segments of some 14-membered macrolide antibiotics have been synthesized from levoglucosan.  相似文献   
5.
6.
Memory Across Eye-Movements: 1/f Dynamic in Visual Search   总被引:1,自引:0,他引:1  
The ubiquity of apparently random behavior in visual search (e.g., Horowitz & Wolfe, 1998) has led to our proposal that the human oculomotor system has subtle deterministic properties that underlie its complex behavior. We report the results of one subject's performance in a challenging search task in which 10,215 fixations were accumulated. A number of statistical and spectral tests revealed both fractal and 1/f structure. First, scaling properties emerged in differences across eye positions and their relative dispersion (SD/M)—both decreasing over time. Fractal microstructure also emerged in an iterated function systems test and delay plot. Power spectra obtained from the Fourier analysis of fixations produced brown (1/f 2) noise and the spectra of differences across eye positions showed 1/f (pink) noise. Thus, while the sequence of absolute eye positions resembles a random walk, the differences in fixations reflect a longer-term dynamic of 1/f pink noise. These results suggest that memory across eye-movements may serve to facilitate our ability to select out useful information from the environment. The 1/f patterns in relative eye positions together with models of complex systems (e.g., Bak, Tang & Wiesenfeld, 1987) suggest that our oculomotor system may produce a complex and self-organizing search pattern providing maximum coverage with minimal effort.  相似文献   
7.
A method for the fabrication of regular microstructures with a high aspect ratio (for example, X-ray gratings) by direct multibeam vector recording in layers of an SU-8 resist is presented. An X-ray beam with a wavelength from 0.4 to 1.7 Å is used for recording. The features of the method are described. The fabricated samples of regular microstructures of the SU-8 resist and gold-plated X-ray masks are presented as finished products.  相似文献   
8.
9.
10.
A simple fabrication technology of hard X-ray masks with thin (50–150μm thick) X-ray transparent bearing membranes made of a new material, i.e., polymerized epoxy resin with graphite filler (hereafter, epoxygraphite), is described. The first results of using such masks in pattern scanning synchrotron X-ray lithography in the exposing radiation wavelength range λ ≈ 0.5–3 Å are presented. The prospects of applications of such masks in the softer spectral range λ ≈ 3–7 Å are considered.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号