57 resultados para DECISIÓN 792

em Chinese Academy of Sciences Institutional Repositories Grid Portal


Relevância:

10.00% 10.00%

Publicador:

Resumo:

茅坪滑坡 茅坪滑坡位于湖北清江隔河岩水库库区近尾部左岸,下距隔河岩水库大坝66km,上距正在施工的水布垭坝址25km。它是目前库区规模最大、变形最严重的一处堆积层滑坡。因该滑坡有发生堵江的极大可能性而倍受有关方面关注。目前,该滑坡已被选作中科院知识创新工程重要方向支持项目“山体滑坡灾害防治中的关键力学问题研究(2001~2005)”的样板地段(封面照片)。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A hybrid finite difference method and vortex method (HDV), which is based on domain decomposition and proposed by the authors (1992), is improved by using a modified incomplete LU decomposition conjugate gradient method (MILU-CG), and a high order implicit difference algorithm. The flow around a rotating circular cylinder at Reynolds number R-e = 1000, 200 and the angular to rectilinear speed ratio alpha is an element of (0.5, 3.25) is studied numerically. The long-time full developed features about the variations of the vortex patterns in the wake, and drag, lift forces on the cylinder are given. The calculated streamline contours agreed well with the experimental visualized flow pictures. The existence of critical states and the vortex patterns at the states are given for the first time. The maximum lift to drag force ratio can be obtained nearby the critical states.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

<正> 在星系密度波的渐近理论中,泊松方程的近似解析解有着十分重要的意义.对于无限薄盘,徐遐生、Bertin等以旋臂倾角参数i_0=m/kr为小参数先后求得相应泊松方程的一、二级渐近解,这些解可以很好地用于比较紧卷的螺旋结构,在平面盘密度波理论中起过重要作用;对于有限厚盘,彭秋和等人也曾得到相应泊松方程的一种解,不过此解需假定物质密度

Relevância:

10.00% 10.00%

Publicador:

Resumo:

三维取向是单分子的一个重要特性,单分子三维取向研究是近年来对单分子研究的又一热点。综述了基于远场扫描的三种探测方法,阐述了其基本原理,分析、比较了各种方法的优缺点,讨论了进行单分子三维取向检测所存在的困难和实际问题,展望了其广阔的应用领域及前景。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

采用丘克拉斯基(Czochralski)技术生长了掺铥硅酸镥(Tm∶Lu2SiO5,Tm∶LSO)晶体;测量了LSO晶体在室温下的非偏振吸收光谱和非偏振荧光光谱;利用窄得-奥菲特(Judd-Ofelt)理论计算了Tm∶LSO晶体的窄得-奥菲特强度参数、振子强度、自发辐射概率、辐射寿命、积分吸收截面和积分发射截面.Tm∶LSO晶体的强度参数为Ω2=9.1355×10-20cm2,Ω4=8.4103×10-20cm2,Ω6=1.5908×10-20cm2;Tm∶LSO晶体在1.9μm附近有明显的发射峰(3F4→3H6跃迁),相应的辐射寿命为2.03 ms,积分发射截面为5.81×10-18cm2,半峰全宽(FWHM)为250 nm.用Tm∶LSO晶体在77 K温度下实现了激光运转.利用792 nm的激光二极管(LD)作为抽运源,获得中心波长为1960 nm的激光输出,抽运阈值为2.13 kW/cm2.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

渐变折射率薄膜因为消除了界面而克服了传统的分层介质膜的固有弊端。探讨了一种基于这种渐变膜系的设计方法。从小波理论及渐变折射率增透理论出发,以分层介质高反膜系为参照,给出了采用梳状(Rugate)滤光片设计不同类型颜色滤光片的设计原理,并以目前背投系统中使用的红、绿、蓝颜色滤光片为指标,理论设计出了具有优良光谱特性的红、绿、蓝颜色滤光片;对该设计结果进行了角度敏感性分析、偏振效应分析并与传统的反射膜叠加法得到的分层膜系进行比较,发现通过梳状滤光片理论设计的滤光片较传统的多层膜滤光片具有更小的角度敏感性和较小

Relevância:

10.00% 10.00%

Publicador:

Resumo:

本发明公开一种剥离型深海鱼皮胶原肽面膜及其制备方法。该方法以提取的深海鱼皮胶原多肽1~10份结合玫瑰纯露1~3份、海藻糖1~2份、菊糖0.5~1份为功能原料,以成膜剂10~30份、无机粉状物10~30份、保湿剂5~10份、油脂5~10份以及表面活性剂1~2份为辅助原料,原料中各组分均以重量计,经溶解、混合、搅拌、均质等工艺制得剥离型深海鱼皮胶原肽面膜。本发明的胶原多肽面膜不仅具有良好的清洁效果,而且可以补充肌肤营养、平整细纹、延缓衰老,是一种经济实用有效的美容护肤化妆品。

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

生物膜是近年来研究的一个热点领域,在水体自净和工业应用方面表现出非常重要的作用。文章介绍了国内外有关生物膜的组成、结构、形成及微生物种群分布特征等研究成果,重点探讨了水环境中生物膜对污染物的吸附和降解作用。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A method of comparing data on protozoan communities with chemical parameters is presented. Using data from an extensive survey of the River Hanjiang in China, each species of protozoa has been given a species pollution value (SPV) related to its occurrence in waters with different degrees of pollution. A comprehensive chemical index is calculated for each site based on water quality standards for eight chemical parameters. The index is calculated from the relationship between the observed levels of each chemical at a site, compared with the limits of the drinking water quality standards of the People's Republic of China. From the distribution of each species at sites with differing chemical index values, a SPV is calculated. The SPV for each species is obtained by summing the logarithmic value of 10 times the chemical pollution divided by the number of chemical parameters, then divided by the stations where the species occurs. The community pollution value (CPV), which is the average SPVs of all protozoa at a site, is used to evaluate water quality. The CPV has been shown to have a close correlation with the degree of water pollution. It is not necessary for all the protozoa in a sample to have SPVs listed in this paper, provided at least 56% of the protozoa in a sample have an SPV value, the CPV will be applicable.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The bulge test is successfully extended to the determination of the fracture properties of silicon nitride and oxide thin films. This is achieved by using long diaphragms made of silicon nitride single layers and oxide/nitride bilayers, and applying comprehensive mechanical model that describes the mechanical response of the diaphragms under uniform differential pressure. The model is valid for thin films with arbitrary z-dependent plane-strain modulus and prestress, where z denotes the coordinate perpendicular to the diaphragm. It takes into account the bending rigidity and stretching stiffness of the layered materials and the compliance of the supporting edges. This enables the accurate computation of the load-deflection response and stress distribution throughout the composite diaphragm as a function of the load, in particular at the critical pressure leading to the fracture of the diaphragms. The method is applied to diaphragms made of single layers of 300-nm-thick silicon nitride deposited by low-pressure chemical vapor deposition and composite diaphragms of silicon nitride grown on top of thermal silicon oxide films produced by wet thermal oxidation at 950 degrees C and 1050 degrees C with target thicknesses of 500, 750, and 1000 mn. All films characterized have an amorphous structure. Plane-strain moduli E-ps and prestress levels sigma(0) of 304.8 +/- 12.2 GPa and 1132.3 +/- 34.4 MPa, respectively, are extracted for Si3N4, whereas E-ps = 49.1 +/- 7.4 GPa and sigma(0) = -258.6 +/- 23.1 MPa are obtained for SiO2 films. The fracture data are analyzed using the standardized form of the Weibull distribution. The Si3N4 films present relatively high values of maximum stress at fracture and Weibull moduli, i.e., sigma(max) = 7.89 +/- 0.23 GPa and m = 50.0 +/- 3.6, respectively, when compared to the thermal oxides (sigma(max) = 0.89 +/- 0.07 GPa and m = 12.1 +/- 0.5 for 507-nm-thick 950 degrees C layers). A marginal decrease of sigma(max) with thickness is observed for SiO2, with no significant differences between the films grown at 950 degrees C and 1050 degrees C. Weibull moduli of oxide thin films are found to lie between 4.5 +/- 1.2 and 19.8 +/- 4.2, depending on the oxidation temperature and film thickness.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

In this paper, a novel algorithm for removing facial makeup disturbances as a face detection preprocess based on high dimensional imaginal geometry is proposed. After simulation and practical application experiments, the algorithm is theoretically analyzed. Its apparent effect of removing facial makeup and the advantages of face detection with this pre-process over face detection without it are discussed. Furthermore, in our experiments with color images, the proposed algorithm even gives some surprises.