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721.
Release of carbon from rocks during their weathering is closely linked to its global circulation. The contents and chemical
forms of inorganic carbon in limestone, mudstone, granite and basalt as well as in their weathering and pedogenic products
have been examined. The results show that a geochemical process of carbon release from the rocks in the early stage of weathering
is followed by its accumulation in the subsequent weathering products.
The environmental geochemical behavior of some heavy metals related to inorganic carbon release and its accumulation are also
studied in this paper. Experimental results show that the capacity of manganese to associate with carbonates increases with
increasing concentrations of the latter, but the behavior of copper is opposite to that of manganese.
Translated by Chen Mingzhong, Chengdu Library, Academia Sinica. 相似文献
722.
The East-Asian summer monsoon meridional circulation (SMMC) cell is simulated together with two vigorous rainbands in terms of a primitive-equation model including in itself a variety of diabatic heating, frictional dissipation and moist processes under the condition of mountains available. Results are comparable to observations. Also, performed are experiments with the reduction of water content, and exclusion of the cumulus convective process and mountain effect. Contrast analyses indicate that the cell is strongly sensitive to the condition of the humidity field in the atmosphere, more intensely at 120o than at 100oE, and the presence (absence) of the cumulus convection has considerable effect on the intensification (weakening) of the cell, with the mountain ranges exhibiting more influence upon the cell at 100o than 120oE. This may suggest that a great difference lies in the cause of the cell for the two meridions. 相似文献
723.
This paper introduces the analysis of three dimensional finite element method for the gravity-arch dam building on the complex ground. The foundation rock of dip and strain-slip, three faults, two weak intercalations and etc. arc considered in this calculation model. Water static pressure, gravity of dam, uplift, temperature stress and so on are computed, including three dimensional osmotic and temperature fields in the foundation. The range of calculation model is about 1400×900×600m2 . There are 1845 elements of all kinds, 3280 nodes in the network of finite element. The superlax iterative method is used to solve, and three dimensional perspective and software of after treatment are applied in analyses. The dimension of this computation is large, various results of treating complex problems are reasonable. The important basis has applied to designing unit. The computation is important practical significance for Geheyan Dam which is being built. 相似文献
724.
本文用近13年200hPa高空风资料得到了夏半年(5—10月)逐月平均全球热带风场,发现如下一些主要结果: (1)在亚洲地区对流层上部反气旋存在两个中心;一个在青藏高原上空;一个在伊朗和阿富汗地区。两者的演变不同。伊朗高压的北推和撤退都比青藏高原上的早。北美墨西哥高压的变化在时间上与伊朗高压很相似。 (2)北太平洋中部高空槽(TUTT)出现在5—10月,8月份最强,位置最北;北大西洋中部高空槽出现在5—9月,7—8月最强。 (3)南半球冬季有三个主要的长波脊和长波槽,分别位于大陆以西和以东海区。 相似文献
725.
726.
The properties of rock resitivity were studied under pressure, particularly with “stress reversal”, a procedure in which the
pressure applied was increased and decreased.
It was observed that, 1) With pressure increasing, the main feature of resistivity change was increase-steady-decrease for
high-saturation rock samples (saturation 70–100%). But the main feature for low-saturation samples was different. 2) In 10
out of 11 cases of “stress reversal” for high-saturation samples the resistivity droped (about 2%). Such drop could explain
the anomalies in geoelectricity terms, which are commonly observed before earthquakes in China. 3) It was also observed shortly
before rock failure that, a) the resistivity drops more dramatically (about 20%) during “stress reversal” period, which is
much more than ordinary drops. b) these drops occurred not only during stress decrease but also during stress increase. c)
Resistivity exhibits anisotropy: the resistivity along different directions may differ by 10%. These three features may indicate
that the rock is nearing failure, while ordinary resistivity drops are only connected with “stress reversal” and may not mean
the imminence of rock failure. 4) Resistivity increase was observed during the “stress reversal” period for low-saturation
rock samples.
The results mentioned above were explained with the effect of water flowing in and out of the cracks of rock. The temporary
factors which yield a reduction of the maximum main stress, may enhence the possibility of earthquake occurrence. 相似文献
727.
应力波在波阻抗连续变化的弹性杆中的演化 总被引:2,自引:2,他引:2
利用特征线方法数值模拟计算了应力波在截面或弹性模量连续变化的弹性杆中的反射,同时也讨论了应力波脉冲宽度对反射波波形特征的影响,其结果对桩基测量有一定的参考价值。 相似文献
728.
729.
大气中许多模式可化为F''=AF/F+B(AB≠0)一类非线性常微分方程。利用常微分方程定性理论说明了该方程存在非线性波解,讨论了其周期的计算问题,并求得了波解及其周期的近似表达式。 相似文献
730.
滇中郝家河砂岩铜矿的地球化学及其成因意义 总被引:1,自引:0,他引:1
本文论术字滇中生代地层与矿区及春外围马头山组中铜的时空分布与迁移富集规律,揭示了矿床的沉积-后期叠加改造成因。成矿作用经历了同生沉积形成矿源层,后期叠加改造形成矿体的过程。后期改造中铜元素发生了大量迁移,矿质主要来自矿体之下伏紫色矿源层。 相似文献