青岛市大沽河水源地数值模拟模型     

焦超颖  邱汉学  刘贯群 《中国海洋大学学报(自然科学版)》1994,(Z3)

根据青岛市大沽河流域水文地质条件建立青岛市大沽河水源地数值模拟模型．该模型的建立有助于更好地开发利用地下水，合理调配水资源，实现水源地的合理优化调度．  相似文献   

Comparative Analysis of Risk Assessment of Landslides and Debris Flows of China in 2000 and 2010     

Liu Xilin  Miao Cheng  Tian Chunshan  Qiu Jin&#x  an 《地球科学进展》2016,31(9):926-936

Landslides and debris flows occurr in China frequently and cause disastrous losses of life and property. The risk assessment of landslides and debris flows and their spatial variations were comparatively analyzed in this paper, which has great significance for disaster prevention. This article selected 1 km×1 km grid as the assessment unit and with support of GIS technique, analyzed landslide and debris-flow risk distribution and their spatial variations from 2000 to 2010. The research results indicated that the spatial distribution of risk classes in 2000 and 2010 was obviously discrepant. Overall, taking the Heihe-Tengchong population density line as the boundary, the west of the line is mainly low risk area; the east of the line is mainly high risk area. Compared with the risk of 2000, the risk values of 2010 increased, with the high risk area and low risk area enlarged, moderate risk area reduced. The moderate risk area is the most unstable and sensitive risk area, and its risk class variation is significant. However, China is not a region with the high risk of landslide and debris-flow hazard at present. In the following next 10 years, the risk of landslides and debris flows in China will continue to increase.  相似文献   

Assessing the impact of urban development on net primary productivity during 2000–2010 in Taihu Basin     

Guangyu Li  Hui Zhang  Shuang Chen  Jie Qiu  Xiaohui Wang 《Environmental Earth Sciences》2016,75(18):1266

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Sensitivity analysis of modelled responses of vegetation dynamics on the Tibetan Plateau to doubled CO2 and associated climate change     

Linjing Qiu  Xiaodong Liu 《Theoretical and Applied Climatology》2016,124(1-2):229-239

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Characteristics of the surface mixed layer depths in the northern South China Sea in spring     

Chunhua Qiu  Yongsheng Cui  Jie Ren  Qiang Wang  Dan Huo  Jiaxue Wu  Huan Liu  Huabin Mao 《Journal of Oceanography》2016,72(4):567-576

The nature and characteristics of the mixed layer depth (MLD) remain uncertain in the northern South China Sea. Using in situ data, we examined the quality of different MLD definitions, investigated the spatial and diurnal variation in the MLD, and examined the mechanisms of mixed layer development during March 23–31, 2014. We made distinct calculations of the MLD; of which two are (a) the depths between two different temperatures (0.2, 0.6 °C) and (b) the depths between two density differences (0.125, 0.25 kg/m³); and the fifth calculation is a depth derived from the optimal linear fitness method. We found that the optimal linear fitness MLD was the best definition for our study region ,and that it deepened from the shelf to the slope. Twenty-four-hour diurnal variation in the MLDs and mixing layers was observed when the ship was moored. Mixing layers were characterized by turbulent dissipation rates. We found that the mixed layer underwent a ‘stable-decaying–developing’ process. During the stable period, the MLD was close to that of the mixing layer, but during the decay/development periods, the MLDs were larger/smaller than those of the mixing layers. We suggest that both velocity shear and buoyancy flux were important in mixed layer development. We quantitatively examined the mechanisms of mixing in the shelf region, with air–sea net heat flux determined to be the major factor, rather than wind speed or current velocity.  相似文献   

Chemical mechanism of flocculation and deposition of clay colloids in coastal aquifers     

Jun Zhou  Lixia Qiu  Guoqing Lin  Xiaoyun Yan  Xiaolan Chen  Honglu Pang 《中国海洋大学学报(英文版)》2016,15(5):847-852

Seawater intrusion has become one of serious environmental problems in coastal areas. During the replacement of saline water by fresh water in the aquifers, in-situ clay could be released, transport and deposit in the porous media due to the change of hydrodynamic and geochemical conditions, which resulted in the increasing of particle size, plugging of pores and reduction of the permeability. Batch experiments and sand column experiments were explored to study the relationships between the flocculation of in-situ clay and geochemical conditions, by changing ionic strength and ionic type of clay suspension. Column outflow was analyzed for suspended particles and electrical conductivity. The total percentage of colloid straining and interception distribution in porous media was calculated. The results indicate that porous media had an effect on the interception of clay colloid particles with about 10 percent clay colloids captured due to the rough surfaces and spatial structure of porous media. Ionic strength played a key role on the permeability reductions. The higher ionic strength is, the greater the amount of colloidal particles trapped. Ionic type also had a significant effect on the interception of clay colloid particles. Ripening was the main mechanism for the interception within porous media when the bulk solution was potassium chloride while blocking happened when the bulk solution was sodium chloride. The distribution of clay colloids in porous media was heterogeneous. The closer to the sand column inlet was the less interception of clay colloids was. The results can provide the scientific basis for preventing the water sensitivity during the process of salty aquifer restoration.  相似文献   

Lessons Learnt from Measurements of Vertical Pressure at a Top Coal Mining Face at Datong Tashan Mines,China     

Jing Xie  Mingzhong Gao  Ru Zhang  Shengwei Li  Qiang Tan  Zhiqiang Qiu 《Rock Mechanics and Rock Engineering》2016,49(7):2977-2983

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Zircon U–Pb and Molybdenite Re–Os Ages of the Lakange Porphyry Cu–Mo Deposit,Gangdese Porphyry Copper Belt,Southern Tibet,China          下载免费PDF全文

Qiu‐Feng Leng  Ju‐Xing Tang  Wen‐bao Zheng  Bin Lin  Pan Tang  Hao Wang  Hai‐Feng Li 《Resource Geology》2016,66(2):163-182

The Lakange porphyry Cu–Mo deposit within the Gangdese metallogenic belt of Tibet is located in the southern–central part of the eastern Lhasa block, in the Tibetan Tethyan tectonic domain. This deposit is one of the largest identified by a joint Qinghai–Tibetan Plateau geological survey project undertaken in recent years. Here, we present the results of the systematic logging of drillholes and provide new petrological, zircon U–Pb age, and molybdenite Re–Os age data for the deposit. The ore‐bearing porphyritic granodiorite contains elevated concentrations of silica and alkali elements but low concentrations of MgO and CaO. It is metaluminous to weakly peraluminous and has A/CNK values of 0.90–1.01. The samples contain low total REE concentrations and show light REE/heavy REE (LREE/HREE) ratios of 17.51–19.77 and (La/Yb)_N values of 29.65–41.05. The intrusion is enriched in the large‐ion lithophile elements (LILE) and depleted in the HREE and high field‐strength elements (HFSE). The ore‐bearing porphyritic granodiorite yielded a Miocene zircon U–Pb crystallization age of 13.58 ± 0.42 Ma, whereas the mineralization within the Lakange deposit yielded Miocene molybdenite Re–Os ages of 13.20 ± 0.20 and 13.64 ± 0.21, with a weighted mean of 13.38 ± 0.15 Ma and an isochron age of 13.12 ± 0.44 Ma. This indicates that the crystallization and mineralization of the Lakange porphyry were contemporaneous. The ore‐bearing porphyritic granodiorite yielded zircon εHf(t) values between ?3.99 and 4.49 (mean, ?0.14) and two‐stage model ages between 1349 and 808 Myr (mean, 1103 Myr). The molybdenite within the deposit contains 343.6–835.7 ppm Re (mean, 557.8 ppm). These data indicate that the mineralized porphyritic granodiorite within the Lakange deposit is adakitic and formed from parental magmas derived mainly from juvenile crustal material that partly mixed with older continental crust during the evolution of the magmas. The Lakange porphyry Cu–Mo deposit and numerous associated porphyry–skarn deposits in the eastern Gangdese porphyry copper belt (17–13 Ma) formed in an extensional tectonic setting during the India–Asia continental collision.  相似文献   

Irregular wave-induced seepage action on cylinders resting on rubble mound foundation     

Qiu Dahong  Yang Gang 《海洋学报(英文版)》1996,15(3):377-395

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地下水环境背景值及其确定方法   总被引：4，自引：0，他引：4  

邱汉学  黄巧珍 《中国海洋大学学报(自然科学版)》1994,(Z3)

本文讨论了地下水环境背景值的概念和特征，指出环境背景值具有区域差异性和时间差异性，它是一个随时间渐变的范围值，属于某个区域（环境单元）而不是一个点．总结了已有的环境背景值确定方法及其优缺点，并提出在污染区可采用历时曲线法．为使背景值更可靠，多神方法的相互检验是必要的．  相似文献