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101.
Kazuaki Kawamoto Tadahiro Hayasaka Teruyuki Nakajima David Streets Jung-Hun Woo 《Atmospheric Research》2004,72(1-4):353
The relationship between SO2 emissions and the effective particle radius of low-level water clouds (re) over China was investigated to determine anthropogenic effects on clouds. Sulfur dioxide emission values were obtained from a statistical inventory, and re origins were retrieved by satellite remote sensing on a 0.5° grid. Comparisons between annual mean SO2 emissions and re showed generally decreasing re values, explained by the Twomey effect. The existence of the Twomey effect is supported by comparisons with simulated aerosol optical depths. Results further suggest that clouds over land show sensitivity to the Twomey effect as well as clouds over the ocean. 相似文献
102.
On the Measurement of the Tensile Strength of Soft Rocks 总被引:8,自引:4,他引:8
Summary. This paper reports on a comparative study of various types of experimental tests for measuring the tensile strength of rocks and rock-like materials. A critical assessment is presented of some widely used laboratory techniques on the basis of experimental data from the literature and from the laboratory investigation performed in this study.Tests were carried out using a triaxial apparatus recently set up at Milan University of Technology. This was designed to reduce random misalignments between specimen and loading frame, which are typical of conventional triaxial cells with external tie bars. The apparatus was then modified to perform various types of tests for determining the tensile strength of materials. An artificial building stone and a natural calcarenite of the Gravina di Puglia geological formation, sampled at Montescaglioso (Matera-Italy) were tested in this research. The experimental investigation included various types of tests, namely the uni-axial, the Brazilian, the ring, the three and four points bending and the Luong test. Specimens of both materials were also compressed to failure in unconfined conditions and loaded cyclically in unconfined tension and compression, Young’s moduli being measured by means of local instrumentation. 相似文献
103.
104.
介绍了形变分析中经常采用的两种方法:直接法和间接法.针对形变分析中关键的形变参数及其精度估计问题,提出了改进间接分析方法,即采用验后方差估值和协方差矩阵重新定义间接法中伪观测值的权矩阵.通过分析和算例表明,改进以后的间接法计算得到的监测网的形变量更能准确的反映实际形变情况. 相似文献
105.
106.
The study on the competitive adsorption shows that the magnitude order of metal ions adsorbed onto oxide and silicate minerals
in near-neutral solution with low ionic strength is in mole/nm2 as follows: CaCO3 > quarte > hydromuscovite > kaolinite > Ca-montmorillonite > goethite > gibbsite. These minerals can be divided into three
groups according to their surface equilibrium constantsK
M of the adsorption reactions, which are the function of the dielectric constants ε of the absorbent minerals. The relationships
between constantsK
M and mineral dielectric constants ε are described as follows: lgK
M
1
= 7.813-26.15/ε lgK
M
2
= 9.030-26.15/ε lgK
M
3
=11.63-26.15/ε for the adsorption reaction: >SO- + Mn+≥SOMn-1)+ (n = 1, 2, 3)
The first group of minerals include quartz, goethite, 1:1 phyllosilicates and other oxide minerals; the second: gibbsite,
brucite and 2:1 phyllosilicates; the third: carbonate, sulphate and phosphorate minerals. The appearance reaction constants
have a variation of magnitude ±0.5 for different metal ions with the same mineral.
This project was financially supported by the National Natural Science Foundation of China (No. 49572091). 相似文献
107.
Chunsheng Li Chifang Chai Xiaolin Li Xueying Mao 《Geostandards and Geoanalytical Research》1998,22(2):195-197
108.
借助最小二乘配置整体解算地壳视应变场 总被引:3,自引:2,他引:1
研究利用多手段(GPS、跨断层等)形变资料,结合定点应变数据解算地壳视应变场的方法,包括利用间接平差法求单元内部的均匀视应变及借助最小二乘配置求水平视应变连续分布。对华北地区GPS监测网1992年、1995年和1996年3期成果进行计算分析,得到其视应变场动态图像。 相似文献
109.
110.
本文介绍如何解决城市规划区域内转角无法定立或转角前后互不通视地段的定线工作,该方法是在间接定线方法基础上采用解析法计算出直线桩及转角桩的放样元素来解决定线工作。提高了平断面图的施测精度,满足了规划部门的要求,取到了较好的经济效益,大大地加快了线路的定线工作。 相似文献