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951.
煤矿瓦斯抽放井要求垂直精度高、井径大,通常采用常规钻探工艺时,需进行3-4次扩孔才能达到最终孔径,施工时间较长,钻进效率较低。此次在端氏煤矿施工的大口径瓦斯抽放井,采用了的一次成井钻进技术及工艺方法,钻进口径达到φ660mm,选用了江汉735型和715型系列镶齿牙轮钻头,采用塔式加重钻具控制并保证了钻井的重直度,采用密度较大的化学泥浆和保持大泵量排渣,避免了井底牙轮钻头的重复破碎,确保了钻进效果。与传统的扩孔工艺相比,缩短了施工周期,成井质量高,提高了钻进效率,降低了钻进成本。 相似文献
952.
953.
Major,trace and rare earth element(REE) concentrations of Late Triassic sediments(finegrained sandstones and mudstones) from Hongcan Well 1 in the NE part of the Songpan-Ganzi Basin, western China,are used to reveal weathering,provenance and tectonic setting of inferred source areas. The Chemical Index of Alteration(CIA) reflects a low to moderate degree of chemical weathering in a cool and somewhat dry climate,and an A-CN-K plot suggests an older upper continental crust provenance dominated by felsic to intermediate igneous rocks of average tonalite composition.Based on the various geochemical tectonic setting discrimination diagrams,the Late Triassic sediments are inferred to have been deposited in a back-arc basin situated between an active continental margin(the Kunlun-Qinling Fold Belt) and a continental island arc(the Yidun Island Arc).The Triassic sediments in the study area underwent a rapid erosion and burial in a proximal slope-basin environment by the petrographic data. while the published flow directions of Triassic lurbidites in the Aba-Zoige region was not supported Yidun volcanic arc source.Therefore,we suggest that the Kunlun-Qinling tcrrane is most likely to have supplied source materials to the northeast part of the Songpan-Ganzi Basin during the Late Triassic. 相似文献
954.
The relationship between runoff and ground temperature in glacierized catchments in China 总被引:1,自引:1,他引:0
Ren-sheng Chen Wen-wu Qing Shi-yin Liu Hai-dong Han Xiao-bo He Jian Wang Guang-yue Liu 《Environmental Earth Sciences》2012,65(3):681-687
A single parameter index method, in which ground temperature and air temperature is the sole input variable, respectively,
is used to evaluate and compare the glacial runoff in three typical glacier catchments, Dongkemadi glacier catchment in Tibetan
plateau, Koxkar glacier catchment and the headwater catchment of Urumqi River catchment in Tianshan Mountains in West China.
The method based on ground temperature is an attempt to evaluate glacier runoff in elevated terrains, as few studies have
focused specifically on the association between glacier runoff and ground temperature. The results identify ground temperature
versus a certain depth, which is a critical factor that affected glacier hydrological processes and showed that runoff data
is much better correlated with ground temperature than air temperature. Especially, at the latter two catchments, the largest
coefficients of exponential relationship R
2 between glacier runoff and ground temperature are 0.9 and 0.83, respectively. The accuracy of the method makes it possible
to estimate the glacier runoff with a certain depth ground temperature at a certain site, which may provide a new approach
to evaluate the glacier runoff for areas where there is a lack of observation data. 相似文献
955.
Thermal regime of a supraglacial lake on the debris-covered Koxkar Glacier, southwest Tianshan, China 总被引:1,自引:0,他引:1
A supraglacial lake was surveyed on the Koxkar Glacier in southwest Tianshan from July to September 2007 and July to September 2008, and the temperature variation characteristics of the lake, debris and debris-free ice were analyzed at different depths to determine the thermal regimes. In addition, the discrepancies of temperature variation characteristics were investigated for different geomorphic units of the ablation zone of the Koxkar Glacier. It was found that daily temperature variation curves for deep water are V-shaped because meltwater from the glacier surface at temperatures of around 0°C feeds the lake and mixes with the relatively high-temperature surface water during the day. As the water temperature rises to approximately 4°C, the mixed water sinks and forms a low-temperature trough in the deep water of the lake in the middle of the day. The vertical lapse rate of the lake water temperature against depth (?0.33°C/m) has a magnitude lower than that of the debris (?4.29°C/m) and that of the debris-free ice (?0.38°C/m) in the Koxkar Glacier??s ablation zone. The temperature curve for the surface water largely varied between the temperature curves for the debris at depths of 0.2 and 0.5?m. The surface thermal condition of the ablation zone is significantly affected by the daily weather, and there is a limited influence in debris at a depth of 1?m and in the lake at a depth of 5?m. 相似文献
956.
Combined analyses of chemometrics and kriging for identifying groundwater contamination sources and origins at the Masan coastal area in Korea 总被引:2,自引:2,他引:0
Tae Hyung Kim Sang Yong Chung Namsik Park Se-Yeong Hamm Seung Yeop Lee Byung-Woo Kim 《Environmental Earth Sciences》2012,67(5):1373-1388
Hydrogeochemical analyses including the basic statistics of chemical components, Piper??s trilinear diagram, and Mazor??s compositional bivariate diagram revealed that the main source and origin of groundwater contamination was seawater intrusion in the study area. However, the other sources and origins of groundwater contamination could be found by the combined analyses of chemometrics and kriging. Cluster analysis was helpful for the classification on the basis of the contamination characteristics of groundwater quality; however, it was not sufficient for the apportionment of groundwater contamination sources. Factor analysis (FA) determined three factors with 81.07% in total variance: Factor 1 for seawater contamination, Factor 2 for nitrate contamination, and Factor 3 for iron contamination. Factor analysis determined the sources of groundwater contamination; however, it could not discover the origins of contaminants except Factor 1. In backward stepwise mode, discriminant analysis decreased the number of parameters from 18 to 6 in discriminating the contaminant type with 96.2% correctness. TDS, Ca, NO3, Mn, Fe, and Br were the most significant parameters for the discrimination of contaminants. Kriging analysis was very useful for the understanding of correlation and similarity between contaminants and factors of FA, and for the investigation of contaminant origins. It also showed that the similarity between factor scores and contaminant concentrations was proportional to the magnitudes of factor loadings for contaminants. This study represented that the combined analyses of chemometrics and kriging were very indispensable to the identification of groundwater contamination sources and origins, as well as for the spatial classification and assessment of groundwater quality. 相似文献
957.
国土空间规划"一张图"实施监督信息系统是在国土空间基础信息平台和国土空间规划"一张图"基础上,为国土空间规划编制、审查、实施、监督提供技术支撑的信息化系统.该系统引入一种用于三维可视化的倾斜摄影数据采集方法,构建三维立体"一张图",真实地浏览和展示数据,开发"一键式"综合分析功能,将复杂空间分析步骤高度集成和定制化,建立监测预警大数据平台.该系统可辅助审查及决策,有效提升管理部门办事效率,全面提升国土空间规划动态监测、综合监管及社会公众服务能力,助力自然资源管理及空间治理迈向智慧化. 相似文献
958.
Polybrominated diphenyl ethers (PBDEs) are now found ubiquitously in the aquatic environment and biota, and there is a growing concern that PBDEs may disrupt endocrine systems, leading to reproductive impairments of aquatic animals. In our study, zebrafish (Danio rerio) were exposed to the 5 ng/L, 1 μg/L and 50 μg/L of DE-71 for the duration of the whole life cycle (120 days, from eggs to adults). The expression of selected genes along the brain-pituitary-gonadal (BPG) axis and liver, and the levels of plasma sex hormones were examined. In male fish, up-regulation of GnRH in brain, FSHβ and LHβ in pituitary, FSH-receptor, LH-receptor, and CYP19a in testis was clearly evident, while down-regulation of CYP11a and 3β-HSD was found in testis. In female fish, a 2.4-fold up-regulation of 3β-HSD was found in ovary upon exposure to 50 μg/L of DE-71. GnRH in brain, FSHβ and LHβ in pituitary were also up-regulated, while ERβ, TH and TPH in brain and GnRH-receptor in pituitary were significantly down-regulated. Hepatic ERα, AR and VTG in males were all down-regulated, while hepatic ERα and AR in female were up-regulated. Serum estradiol (E2) was reduced in both male and female upon exposure to DE-71, while significant increases in serum testosterone (T) and 11-keto-testosterone (11-KT) were only found in male but not female fish. The ratio of T/E2 as well as the ratio of 11-KT/E2 in male fish increased in a dose-dependent manner upon exposure to DE-71. Our overall results showed that whole life exposure of DE-71 altered the expression of regulatory genes and receptors at all three levels of the BPG axis in zebrafish, and the responses are sex dependent. The observed disruption of GnRH and GtHs can be further related to the subsequent disruption in both levels and balance sex steroid hormones. 相似文献
959.
根据具有垂直对称轴的横向各向同性(VTI)介质中的一阶准P波方程,导出了该方程在交错网格中逆时延拓的高阶有限差分格式,给出了其稳定性条件,采用完全匹配层吸收边界条件解决边界反射问题,分别应用下行波最大能量法和归一化互相关成像条件, 实现了VTI介质中准P波方程的叠前逆时深度偏移.各向异性Marmousi模型的试算结果表明,VTI介质准P波方程叠前逆时深度偏移算法不受地下构造倾角和介质横向速度变化的限制,对复杂模型具有良好的成像能力;应用归一化互相关成像条件能得到更好的成像效果.对比该模型的各向异性和各向同性逆时偏移剖面表明,在各向异性地区采集的纵波数据用各向异性偏移算法理论上能得到更好的成像结果. 相似文献
960.
Watershed water quality models are increasingly used in management. However, simulations by such complex models often involve significant uncertainty, especially those for non-conventional pollutants which are often poorly monitored. This study first proposed an integrated framework for watershed water quality modeling. Within this framework, Probabilistic Collocation Method (PCM) was then applied to a WARMF model of diazinon pollution to assess the modeling uncertainty. Based on PCM, a global sensitivity analysis method named PCM-VD (VD stands for variance decomposition) was also developed, which quantifies variance contribution of all uncertain parameters. The study results validated the applicability of PCM and PCM-VD to the WARMF model. The PCM-based approach is much more efficient, regarding computational time, than conventional Monte Carlo methods. It has also been demonstrated that analysis using the PCM-based approach could provide insights into data collection, model structure improvement and management practices. It was concluded that the PCM-based approach could play an important role in watershed water quality modeling, as an alternative to conventional Monte Carlo methods to account for parametric uncertainty and uncertainty propagation. 相似文献