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21.
应用地壳波浪与镶嵌构造学说对富氏谱分析法提取地壳垂直形变信息的科学性做了地质学意义上的阐释 ,并提出了根据多期形变资料提取特定波段上构造策应力的数学模型 相似文献
22.
23.
浙江省现有地下水开采潜力的分析与评价方法存在着不足,本文结合乐清市地下水资源开发利用规划实例,浅析浙江省地下水资源开采潜力分析与评价的综合影响因素. 相似文献
24.
T. Masuda T. Shibutani T. Ochiai S. Akagi H. Yamaguchi Y. Kugimiya N. Kimura T. Miyake 《Journal of Metamorphic Geology》2004,22(3):199-205
Evidence is presented of a lateral variation in differential stress during metamorphism along a regional metamorphic belt on the basis of the proportion of microboudinaged piemontite grains (p) in a quartz matrix in metacherts. It is proposed that p is a practical indicator of relative differential stress. Analysis of 123 metacherts from the 800 km long Sambagawa metamorphic belt, Japan, reveals that p‐values range from < 0.01 to 0.7 in this region. Most samples from Wakayama in the mid‐belt area have p‐values of 0.4–0.6, whereas those from western Shikoku have p‐values of < 0.1. This difference cannot be explained by variations in metamorphic temperature, and is instead attributed to a regional, lateral variation in differential stress during metamorphism. 相似文献
25.
D. Prandle 《Estuarine, Coastal and Shelf Science》1985,20(5):615-635
An examination is made of the circulation in narrow estuaries subject to a predominant tidal forcing. Velocity structures are derived separately for residual flow components associated with (a) river flow, (b) wind stress, (c) a well-mixed longitudinal density gradient and (d) a fully stratified saline wedge. Dimensionless parameters are introduced to indicate the magnitude of each component and these parameters are evaluated for 9 major estuaries, thereby revealing their sensitivity to each component.For a channel of constant breadth and depth, formulae are deduced for the length of saline intrusion, L. Comparisons with observed data show that such formulae may be used with confidence to predict changes in L arising from variations in river flow, tidal range or channel depths.The level of stratification is shown to be related to a product of two parameters, one associated with velocity structure and a second involving the square of the ‘flow ratio’ (i.e. residual velocity/amplitude of the tidal velocity). This relationship provides a simple classification system for estuarine stratification which can be used to indicate the sensitivity of any particular estuary to changing conditions. 相似文献
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This paper presents a numerical model for predicting the dynamic response of rock mass subjected to large‐scale underground explosion. The model is calibrated against data obtained from large‐scale field tests. The Hugoniot equation of state for rock mass is adopted to calculate the pressure as a function of mass density. A piecewise linear Drucker–Prager strength criterion including the strain rate effect is employed to model the rock mass behaviour subjected to blast loading. A double scalar damage model accounting for both the compression and tension damage is introduced to simulate the damage zone around the charge chamber caused by blast loading. The model is incorporated into Autodyn3D through its user subroutines. The numerical model is then used to predict the dynamic response of rock mass, in terms of the peak particle velocity (PPV) and peak particle acceleration (PPA) attenuation laws, the damage zone, the particle velocity time histories and their frequency contents for large‐scale underground explosion tests. The computed results are found in good agreement with the field measured data; hence, the proposed model is proven to be adequate for simulating the dynamic response of rock mass subjected to large‐scale underground explosion. Extended numerical analyses indicate that, apart from the charge loading density, the stress wave intensity is also affected, but to a lesser extent, by the charge weight and the charge chamber geometry for large‐scale underground explosions. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
28.
Vertical profiles of chl-a and primary productivity in the middle continental shelf area and eddy area of the East China Sea
were studied using data from a cruise in the East China Sea in February to March, 1997 and a cruise in July, 1998. The results
showed that chl-a vertical distribution closely related to in situ hydrological and nutrient conditions. Chla-a concentration
ranged from 0.22 to 0.35 mg/m3 and 0.93–1.09 mg/m3 in the eddy area and in the middle continental shelf area, respectively. In both areas, chl-a concentrations in deep layers
were slightly higher than those in shallow layers, but was of the same order of magnitude. In summer, when a thermocline existed
in the water column, highest chl-a concentrations appeared at the base of the thermocline layers in both areas. In the eddy
area, chl-a concentration maximized at 31.743 mg/m3, and averaged 1.143 mg/m3 below 30 m depth. In the middle continental shelf area, the highest chl-a concentration was 2.120 mg/m3, the average was 1.168 mg/m3. The primary productivity reached 1418.76 mgC/(m2·d) in summer and 1360.69 mgC/(m2·d) in winter. In the eddy area, the primary productivity was 787.50 mgC/(m2·d) in summer and 159.04 mgC/(m2·d) in winter. Vertical carbon sinking rate from the deep layer to the bottom in both areas is also discussed in this paper.
Contribution NO. 4183 from the Institute of Oceanology, Chinese Academy of Sciences.
Project No. 49636210 supported by NSFC. 相似文献
29.
张赤军 《大地测量与地球动力学》2002,22(4):31-34
介绍当今确定天文大地垂偏差的新仪器-CCD自动天体测量仪和确定两点间高程异常差的新方法,该方法用单极坐标代替繁琐的双极坐标进行计算,讨论了天文重力水准的误差及垂线偏差非线性影响等问题,估计在不久的将来,用这一手段施测山区似大地水准面的精度可望达到厘米级。 相似文献
30.