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排序方式: 共有363条查询结果,搜索用时 15 毫秒
331.
I. Lyberg 《Journal of statistical physics》2005,119(3-4):747-764
The fourth virial coefficient is calculated exactly for a fluid of hard spheres in odd dimensions up to 11. 相似文献
332.
硬X射线微米探针高精度样品定位系统 总被引:1,自引:0,他引:1
介绍了上海光源硬X射线微聚焦光束线站(BL15U1)的高精度样品定位系统。该系统由离线样品显微镜系统、在线样品实验系统和高精度定位样品架三部分组成。通过编译控制程序、样品架定位、坐标转换,将样品的在线X射线荧光成像实验和离线显微镜观察进行有效结合,首次在国内同步辐射装置上实现样品在微米范围内的快速离线定位。该系统帮助科研工作者在利用微束X射线研究物质微区特征时,快速准确地寻找微区研究对象。利用金网进行X射线荧光成像实验,对比离线高倍显微镜下金网各结点的坐标,对样品定位系统的精度进行验证。结果表明,该样品定位系统在X方向的平均误差为1.3 μm,Z方向的平均误差为2.5 μm。该系统不仅简便快速、准确可靠,节约宝贵的实验时间,也为同步辐射微聚焦线站开展样品自动对焦方法提供技术前提。 相似文献
333.
Yating Huang Xinchun Lu Guoshun Pan Bill Lee Jianbin Luo 《Applied Surface Science》2009,255(22):9100-9104
Scrub, ultrasonic and megasonic are widely used in industry as post-CMP (chemical mechanical polishing/planarization) cleaning procedure. In this paper experiments and results are described to analyze the particle contaminations of hard disk substrate after each process of post-CMP cleaning. A scatter spot method has been exploited to detect the location and characteristics of the particles. SEM with EDX is used to observe and analyze the particles’ shape and size as well as the elements. The results indicate that brush scrub process can remove 99% contaminations after CMP but not that efficient for submicron particle. Megasonic is a refined method for cleaning nano-particles. However, contaminations like metallic particles and bacteria from the equipment may cause pollution. The abrasive particles embedded in the plating pits cannot be removed by mechanical force. Pollution in the dryer is also discussed. 相似文献
334.
Hard magnetic Sm2Fe17Nx thin films were prepared by dc magnetron sputtering and subsequent nitrogenation process. The results show that the sputtering parameters determine the film composition, which determines the crystal structure and magnetic properties. When the gas pressure varies from 1.2 to 2.1 Pa and power varies from 40 to 60 W, higher Sm content (>11.3 at%) is obtained, giving rise to improved coercivity HC and remanence ratio MR/MS. The optimal HC of 2127.8 Oe and MR/MS of 0.53 are obtained when the gas pressure and power reach 1.2 Pa and 50 W, respectively. In addition, it is found that the pure single Sm2Fe17 phase can be observed when the ratio of Fe/Sm exceeds 7.1 by controlling the sputtering parameters to adjust the composition. 相似文献
335.
336.
上海深部硬土渗透特性试验研究 总被引:1,自引:0,他引:1
上海深部硬土层的沉降显著滞后于水位变化, 本文通过一系列渗透试验进行了相关问题的研究, 包括初始水力坡度, 结核对渗透性的影响, 压力对渗透性的作用, 以及孔隙比与渗透系数之间规律的研究。结果表明硬土的渗透速率与水力坡度之间符合良好的线性关系, 满足达西定律; 大量的致密结核对渗透性影响微弱; 应力增加导致渗透性降低, 渗透系数与孔隙比呈指数规律变化。基于试验成果评价了1989~2007年天然硬土的渗透性变化, 此期间硬土层边界水位下降了近30m, 硬土层的沉降造成了该层渗透性的降低, 但土层的平均渗透系数改变不大。 相似文献
337.
Yurtseven H 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):910-914
This study gives our analysis of the Raman bandwidths using the soft mode-hard mode coupling model applied to ammonium halides. The temperature dependence of our observed bandwidths for the nu5(174 cm-1) Raman mode of NH4Cl and nu5(177 cm-1) Raman mode of NH4Br, is analyzed close to phase transitions. From our analysis, we obtain beta=0.13 as the values of the critical exponent for the order parameter in the first order phase region for the ammonium halides. 相似文献
338.
We present exact solutions of Bean’s critical state model for some sample shapes having non-zero demagnetization factorN. Virgin and hysteresis magnetization curves are obtained for samples in the shape of (i) a sphere (ii) a spheroid (iii) a
cylinder of circular cross-section with its axis perpendicular to the field and (iv) a cylinder of elliptical cross section
with its axis perpendicular to the field. Some interesting features seen in these first solutions forN ≠ 0 are discussed. 相似文献
339.
C. Domshlak S. Prestwich F. Rossi K. B. Venable T. Walsh 《Journal of Heuristics》2006,12(4-5):263-285
Many real life optimization problems are defined in terms of both hard and soft constraints, and qualitative conditional preferences.
However, there is as yet no single framework for combined reasoning about these three kinds of information. In this paper
we study how to exploit classical and soft constraint solvers for handling qualitative preference statements such as those
captured by the CP-nets model. In particular, we show how hard constraints are sufficient to model the optimal outcomes of
a possibly cyclic CP-net, and how soft constraints can faithfully approximate the semantics of acyclic conditional preference
statements whilst improving the computational efficiency of reasoning about these statements.
This material is based in part upon works supported by the Science Foundation Ireland under Grant No. 00/PI.1/C075 相似文献
340.
介绍了经典非Abel等离子体满足的动力论方程及求解的方法.同时考虑夸克与反夸克贡献得到解析的有效质量(同时包含温度和化学势)的表达式,进而推出包含化学势的硬热圈自能,和场论所得结果完全一致. 相似文献