北极Svalbard地区气候变化特征及其与青藏高原对比   总被引：6，自引：0，他引：6  

康世昌  阎宇平 《地理科学》1998,18(4):312-319

通过分析Ｓｖａｌｂａｒｄ地区近８０ａ来的气候变化表明,其总趋势为缓慢变暖,但７０年代后期Ｓｖａｌｂａｒｄ地区的降温是全球升温的一个例外。同时对典型台站的分析得出：Ｓｖａｌｂａｒｄ地区与青藏高原气候变化存在着一定相关性,但局地的气候变化原因导致了两地之间的某些差异。  相似文献   

声波测井在碎屑岩沉积压实研究中的应用   总被引：1，自引：0，他引：1  

周文英  康志宏  虎北辰  魏历灵 《新疆地质》1998,(2)

通过对塔里木盆地北部阿克库勒地区 5口钻井泥质岩的声波时差及相应的孔隙度、古地层压力研究 ,求得本区的平均压实方程。认为本区 310 0～ 350 0 m属于正常压实层 ,其下属于欠压实层段。初步分析各时代流体的封闭时间和主要目的层欠压实异常类型。结合地震勘探资料 ,提出低速异常带中的更低异常区是找油领域之一。  相似文献   

祁连山冷龙岭南坡晚第四纪冰川演化序列   总被引：11，自引：4，他引：7  

康建成  朱俊杰 《冰川冻土》1992,14(4):352-359

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不同来流条件下四圆柱尾流场试验研究     

高洋洋  蘧鑫晨  杨康  张宝峰 《海洋工程》2018,36(6):84-91

基于粒子图像测速技术(PIV)对小间距比比L/D=1.5工况下方形布置四圆柱在不同来流角角α(α=0°、15°、30°、45°)条件下的尾流流场特性进行了试验研究,分析了不同来流角度条件下四圆柱瞬时和时均尾流流场特征,获得了瞬时和时均速度矢量、涡量等值线、流线拓扑及雷诺应力分布随来流角度变化的规律。试验结果表明,来流角度对方形布置四圆柱尾流形态有显著影响。四圆柱瞬时尾流形态随来流角度增大可分为延伸体流动流态(α=0°)、尾流剪切层附着流态(α=15°、30°)及尾流剪切层共同脱落流态(α=45°)三种流态。当来流角度增大时,四圆柱下游断面平均流向速度分布由"W"形向"U"形转变,时均雷诺正应力及雷诺剪切应力等值线分布特征也会发生明显改变。  相似文献   

鄂尔多斯盆地Y区块长6致密油层裂缝特征     

康立明  任战利  张林  魏斌  王武兵 《吉林大学学报(地球科学版)》2020,50(4):979-990

长6致密油层是鄂尔多斯盆地Y区块的主力产层，裂缝发育。目前单井产能低，水淹和水窜现象严重，部分水井注水困难，严重影响了开发效果。为了解决影响开发效果较为严重的裂缝问题，本文通过野外露头和岩心宏观、微观观察，注水指示曲线和压力降落试井资料分析，应力测定，停泵压力梯度与上覆应力梯度关系研究，结合沉积环境，对天然裂缝、人工裂缝发育特征，人工裂缝影响因素，天然裂缝对人工裂缝性质的影响、人工裂缝形态及分布规律等方面进行研究。结果表明：研究区长6油层宏观裂缝主要是以垂直缝为主的区域性构造裂缝，微裂缝主要是以水平缝为主的成岩缝；人工裂缝主要受控于天然裂缝，天然裂缝主要受控于砂体厚度与泥质体积分数，砂体厚度越薄越易形成天然裂缝，泥质体积分数越高越易形成变形构造。  相似文献   

Simulation for the propulsion of a micro-hydro robot with an unstructured grid     

M.C. Kim  H.K. Kang  H.H. Chun  H.J. Choi  H.J. Kim 《Ocean Engineering》2008,35(8-9):912-919

The flow mechanism of contractive and dilative motion was numerically investigated to obtain a propulsive force in a highly viscous fluid. The computing program for the analysis of complicated motions was numerically developed with a cell-centered, unstructured grid scheme. The developed program was validated by the well-known equation of an oscillating plane below viscous fluid for an unsteady problem, which is known as Stokes’ second problem. Validation has continued through comparison with the experimental results.In this case, sinusoidal motion was applied to the validation, instead of trochoidal motion, because it was very difficult to actually simulate trochoidal motion in this experiment. Finally, the validation and comparison with the nodal-point scheme was accomplished by Stokes’ problem, which is the famous problem at a low Reynolds number. The validated code was applied to contractive and dilative motion in a narrow tube, whose motion was embodied by trochoidal movement. In a highly viscous fluid, such as a very sticky honey or a swamp, the computed results show that a viscous force can be used for propulsion instead of a dynamic force.From the present results, it was found that a propulsive force can be obtained by contractive and dilative motion at a low Reynolds number, which can be applied to the propulsion of micro-robots in a highly viscous fluid such as a blood vessel or a swamp. This research could also be considered fundamental research for the propulsion of micro-hydro robots, which are expected to be actively studied in the future in accord with further development of nanotechnology.  相似文献   

On the unusual holocene carbonate sediment in lake Nam Co, central Tibet     

Minghui Li  Shichang Kang  Liping Zhu  Feiyue Wang  Junbo Wang  Chaolu Yi  Xiaomin Fang  Manping Xie 《山地科学学报》2009,6(4):346-353

In lacustrine sediments, aragonite is a widespread mineral, whereas monohydrocalcite is a rare carbonate mineral. In the cold and high-attitude Xizang （Tibetan） Plateau, where aragonite has been commonly found in lacustrine sediments, there is no aragonite, but low-Mg calcite, monohydrocalcite and trace dolomite. The lake receives solutes primarily from surface runoffs and remains fairly constant water chemistry for a long time. The total CaCO3 percentage in sediments could be controlled by evaporation and inflow of detrital materials. The absence of aragonite is unusual when compared to other lacustrine sediments from the Tibetan Plateau. This could be due to low Ca/Mg ratio, low salinity, low Mg and Ca concentration. Monohydrocalcite might precipitate from the lake water mediated by biological activities. Low-Mg calcite originated from minor ostracoda shell and the precipitation of lake water with biological activities.  相似文献   

GCMs with implicit and explicit representation of cloud microphysics for simulation of extreme precipitation frequency     

In-Sik Kang  Young-Min Yang  Wei-Kuo Tao 《Climate Dynamics》2015,45(1-2):325-335

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A study of estuarine flow using the roving adcp data     

Kiryong Kang  Daniela Di Iorio 《Ocean Science Journal》2008,43(2):81-90

A study of estuarine flows during a neap tide was performed using 13-hour roving acoustic Doppler current profiles (ADCP) and conductivity-temperature-depth (CTD) profiles in the Altamaha River estuary, Georgia, U.S.A. The least-squared harmonic analysis method was used to fit the tidal (M₂) component and separate the flow into two components: the tidal and residual (M₂-removed) flows. We applied this method to depth-averaged data. Results show that the M₂ component demonstrates over 95% of the variability of observation data. As the flow was dominated by the M2 tidal component in a narrow channel, the tidal ellipse distribution was essentially a back-and-forth motion. The amplitude of M2 velocity component increased slightly from the river mouth (0.45 m/sec) to land (0.6 m/sec) and the phase showed fairly constant values in the center of the channel and rapidly decreasing values near the northern and southern shoaling areas. The residual flow and transport calculated from depth-averaged flow shows temporal variability over the tidal time scale. Strong landward flows appeared during slack waters which may be attributed to increased baroclinic forcing when turbulent mixing decreases.  相似文献   

翡翠贻贝三个野生群体的生化遗传分析     

黄荣莲  李康  杜晓东 《海洋通报》2008,27(1):42-47

采用聚丙烯酰胺梯度凝胶垂直平板电泳对湛江、北海和汕尾三地翡翠贻贝(Perna viridis)野生群体10种同工酶21个的位点的生化遗传特性进行分析.分析结果表明8个位点(Alp-1, Alp-2, G6pdh-1, Me-1, Me-2, Sdh-1, α-Est-5, β-Est-2)具有多态性.湛江、北海、汕尾群体的多态位点比例分别为0.381,0.286,0.381,平均期望杂合度分别为0.6 097, 0.5 407和 0.6 893.群体内杂合度较高,遗传多样性较丰富.群体间的基因分化系数在 0.0 140 ～ 0.0 389 范围内,北海和湛江群体间,湛江和汕尾群体间以及北海和汕尾群体间的遗传相似性分别为0.9 838,0.9 861 和 0.9 630; 聚类分析表明湛江和汕尾群体遗传距离极小,而与北海群体分歧稍明显.上述的结果表明,翡翠贻贝 3 个群体种质资源遗传多样性依然处于良好状态.  相似文献