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21.
The oceanic carbon cycle in the tropical-subtropical Pacific is strongly affected by various physical processes with different temporal and spatial scales, yet the mechanisms that regulate air-sea CO2 flux are not fully understood due to the paucity of both measurement and modeling. Using a 3-D physical-biogeochemical model, we simulate the partial pressure of CO2 in surface water (pCO2sea) and air-sea CO2 flux in the tropical and subtropical regions from 1990 to 2004. The model reproduces well the observed spatial differences in physical and biogeochemical processes, such as: (1) relatively higher sea surface temperature (SST), and lower dissolved inorganic carbon (DIC) and pCO2sea in the western than in the central tropical-subtropical Pacific, and (2) predominantly seasonal and interannual variations in the subtropical and tropical Pacific, respectively. Our model results suggest a non-negligible contribution of the wind variability to that of the air-sea CO2 flux in the central tropical Pacific, but the modeled contribution of 7% is much less than that from a previous modeling study (30%; McKinley et al., 2004). While DIC increases in the entire region SST increases in the subtropical and western tropical Pacific but decreases in the central tropical Pacific from 1990 to 2004. As a result, the interannual pCO2sea variability is different in different regions. The pCO2sea temporal variation is found to be primarily controlled by SST and DIC, although the role of salinity and total alkalinity, both of which also control pCO2sea, need to be elucidated by long-term observations and eddy-permitting models for better estimation of the interannual variability of air-sea CO2 flux.  相似文献   
22.
山东是矿业大省,矿产资源的开发程度较高,但也存在着不容忽视的问题。针对产生这些问题的原因,提出了实现矿产资源可持续开发利用的六项建议,强调应从增强矿产资源的忧患意识、保护生态环境、加强矿产勘查、强化政府管理职能及依靠科技进步等方面加大工作力度。  相似文献   
23.
本文对不同成因类型的锡石晶体形态进行了研究,并从PBC(周期性键链)理论出发,讨论了锡石晶体形态与晶体结构的关系。笔者认为,锡石晶体具有三种F面,即s{111}、e{101}、m{110},与Hartman对同样结构类型的金红石晶面性质划分有所差异。据锡石晶面结构性质所推导的理想晶体形态图,与晶体测量所得到的天然晶体形态图总体上相吻合。  相似文献   
24.
The geochemical behaviours of 26 elements in deep-sea drill core sediments from the Indian Ocean have been investigated with INAA, including Na, K, Ca, Sc, Cr, Fe, Co, Rb, Sr, Zr, Sb, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Hf, Ta, Au, Th and U. Their distribution patterns with depth are also discussed. In terms of the enrichment factors of the respective elements, their residence times in the sea have been calculated by the least squares fitting and are compared with the previous results.  相似文献   
25.
本文从地质地球化学角度对峪耳崖金矿床进行了详细研究,认为该金矿是典型的岩浆热浪型脉状金矿床,金矿与峪耳崖花岗岩(即矿床的主要围岩)为同源岩浆作用的产物,而其源岩物质可能来自深部地壳。黄铁矿中Co/Ni比为1.58,石英中La/Yb比为2.95,δ~(34)S_∑为+2.6‰,δ~(13)O水为+7.03‰,δD为-88.4‰,δ~(13)C为-4.18‰,成矿温度为305~343℃,pH为6.2~6.8,石英包裹体成分中Cl~->F~-、Na~+>K~+,金可能是以Na[AuCl_2],Na[Aucl_4]或Na[AuS]等络合物形式迁移。  相似文献   
26.
Using fused SiO2, CaF2, and SrF2 samples with accurately known dielectric constants, we have evaluated the accuracy and precision of two-terminal dielectric constant measurements on small single crystals using empirically determined edge corrections. Values of κ′ at 1 MHz of 3.836±0.05 for silica, 6.814±0.07 for CaF2 and 6.463±0.09 for SrF2 indicate an accuracy and precision of 1.0–1.5% for samples having areas of 0.05–1.0 cm2. Dielectric constants of BeO, MgO, and CaO measured by this technique are: BeO, κ′a=6.87 and κ′c=7.74; MgO, κ′= 9.90; and CaO, κ′=11.95 where κ′a and κ′c are the dielectric constants parallel to the a and c axes, respectively. Dielectric loss measurements on CaO in vacuum between 5–400 K at 10–105 Hz indicate significant dispersion at temperatures higher than 300 K, but the effect of the losses on the dielectric constant is less than 1% at 1 MHz and 300 K.  相似文献   
27.
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   
28.
柴云来 《探矿工程》1994,(3):28-29,31
介绍了在浅海施工直径2.20m嵌岩桩的技术问题。包括平台的搭设,用刮刀钻头与牙轮钻头钻进克取硬岩一次成孔工艺,利用冲洗液平衡原理处理浅海钻进护简断裂的成孔方法,改进浇灌清孔流程,保证浇灌质量。  相似文献   
29.
The paper introduces the steps and methods of multi-approach,multi-level exploration of buried faults in thick Quaternary sediment regions by taking the test exploration of the Yinchuan active fault as example.Based on the comprehensive analyses of previous data,we choose the Xinqushao Village of Xingqing District of Yinchuan City as the test site for the comprehensive exploration.Firstly,we adopted shallow seismic investigation with group intervals of 10m,5m and 1m to gradually trace layer by layer the master fault of the Yinchuan buried fault from a deep depth to a shallow depth where drilling could be used.Then,with composite geological profile drilling,we determined the precise location and dip angle of the fault.The drilling show the buried depth of the upper offset point is 8.3m.Finally,large-scale trenching revealed that the actual buried depth of the upper offset point of the fault is 1.5m from the ground surface and there are paleoearthquake events of 5 stages.Combined with the preliminary result of corresponding sample age,we conclude the Yinchuan buried fault is a mid to late Holocene active fault.  相似文献   
30.
A novel method of synthesizing seismic wave using wavelet reconstruction is proposed and compared with the traditional method of using theory of Fourier transform. By adjusting the frequency band energy and taking it as criterion, the formula of synthesizing seismic wave is deduced. Using the design parameters specified in Chinese Seismic Design Code for buildings, seismic waves are synthesized. Moreover, the method of selecting wavelet bases in synthesizing seismic wave and the influence of the damping ratio on synthesizing results are analyzed. The results show that the synthesis seismic waves using wavelet bases can represent the characteristics of the seismic wave as well as the ground characteristic period, and have good time-frequency non-stationary.  相似文献   
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