五家矿含水砂层下提高回采标高的可行性   总被引：2，自引：1，他引：1  

田文明  徐文泉  刘宝海  杨凤芝 《煤田地质与勘探》2002,30(3):47-48

通过对五家矿区水文地质条件、煤层顶板、岩石物理力学性质进行分析和研究,提出在五家矿区含水砂层下采煤可以缩小防水煤岩柱,从而提高回采标高。   相似文献   

海拉尔-新帐房断裂带大地构造属性及其意义   总被引：2，自引：0，他引：2  

刘宝山  李仰春  张昱 《地质与资源》2003,12(4):201-205

大兴安岭地区海拉尔-新帐房断裂带是一条多期活动的断裂,为中生代各阶段的岩浆活动提供了就位、喷发空间,同时控制了中生代各阶段地质体的分布,其断裂两侧地质体在分布、规模等方面有着很大的差异.经本次工作研究发现,海拉尔-新帐房断裂是一条具走滑性质的大断裂,在各个阶段表现为不同的构造性质,是区域上大地构造单元的分界断裂,东部为隆起区,西部为拗陷区.  相似文献   

近千年青藏高原的温度变化   总被引：7，自引：0，他引：7       下载免费PDF全文

杨保  Achim Braeuning 《气候变化研究进展》2006,2(3):104-107

通过对昌都树轮d13C、达索普冰芯d18O和先前重建的整个高原温度序列的分析,以及与其他气候代用记录的比较,揭示了青藏高原近1000 a来的温度变化特征。依据昌都树轮d13C年表,指出青藏高原的中世纪暖期发生于1200-1400 AD,该时期的夏季温度比长期平均值或现代（20世纪,下同）约高1.2℃,小冰期（1400-1700 AD）的夏季温度比长期平均值或现代约低0.5℃。近1000 a最暖的时期是13世纪,而最冷的时期是1000-1200 AD,温度比现代约低0.9℃。20世纪的气候变暖主要表现在冬季温度的升高,同期的夏季温度呈微弱的下降趋势。  相似文献   

Interannual variation of evapotranspiration in an eastern Siberian larch forest     

Bao‐Lin Xue  Hikaru Komatsu  Ayumi Kotani  Kyoichi Otsuki  Takeshi Ohta 《水文研究》2012,26(15):2360-2368

In a deciduous larch forest in eastern Siberia, the mean and standard deviation of the total evapotranspiration (E) during May to September (day of year (DOY) = 121–274) for 2003–2006 were 181.5 and 26.4 mm, respectively. The interannual variation (IAV) in the total E was caused by the IAV in E for the canopy‐foliated period (DOY = 164–253), not by the IAV in the dates of leaf expansion and leaf fall. For the years with higher total E, E in the canopy‐foliated period was consistently higher, which corresponded to the higher soil water content in these years. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Modeling Fate, Transport, and Biological Uptake of Selenium in North San Francisco Bay     

Limin Chen  Shannon L. Meseck  Sujoy B. Roy  Thomas M. Grieb  Barbara Baginska 《Estuaries and Coasts》2012,35(6):1551-1570

Selenium behavior in North San Francisco Bay, the largest estuary on the US Pacific coast, is simulated using a numerical model. This work builds upon a previously published application for simulating selenium in the bay and considers point and non-point sources, transport and mixing of selenium, transformations between different species of selenium, and biological uptake by phytoplankton, bivalves, and higher organisms. An evaluation of the calibrated model suggests that it is able to represent salinity, suspended material, and chlorophyll a under different flow conditions beyond the calibration period, through comparison against long-term data, and the distribution of different species of dissolved and particulate selenium. Model-calculated selenium concentrations in bivalves compared well to a long-term dataset, capturing the annual and seasonal variations over a 15-year period. In particular, the observed lower bivalve concentrations in the wet flow periods, corresponding to lower average particulate selenium concentrations in the bay, are well represented by the model, demonstrating the role of loading and hydrology in affecting clam concentrations. Simulated selenium concentrations in higher organisms including white sturgeon and greater scaup also compared well to the observed data in the bay. Finally, a simulation of changing riverine inflows into the bay that might occur as a consequence of proposed hydrologic modifications indicated significant increases in dissolved and particulate selenium concentrations in the bay. The modeling framework allows an examination of the relationship between selenium loads, variations in inflow, in-bay concentrations, and biota concentrations to support management for limiting wildlife impacts.  相似文献   

高密度电阻率法在四川高川茶园沟滑坡勘察中的应用   总被引：2，自引：0，他引：2  

程庆  庹先国  葛宝  李怀良  王诗东 《物探与化探》2012,(1):69-72

将高密度电阻率法用于四川省高川乡茶园沟滑坡地质勘察中,结合钻孔资料确定了滑坡体主滑动面的位置、基岩的埋深及含水程度,为滑坡治理提供可靠的地球物理依据。  相似文献   

成都经济区不同地貌景观区土壤有机碳分布特征及储量估算   总被引：1，自引：0，他引：1  

阚泽忠  金立新  李忠惠  杨振鸿  张华  包雨函 《地球科学进展》2012,27(10):1126-1133

利用四川省成都经济区多目标区域地球化学调查获得的土壤有机碳含量数据,探讨了成都经济区不同地貌景观区土壤有机碳的分布特征。山区表层土壤有机碳含量(SOC)最高(22 g/kg左右),较平原区、丘陵区高一倍以上,丘陵区最低(9.49 g/kg)。成都平原区和东部丘陵区深层土壤碳含量相差不大,且均低于研究区深层土壤碳含量均值(6.99 g/kg)。利用指数模型对单位土壤平均碳量(USCATOC)、有机碳储量(USCATOC,h)、有机碳丰度指数(R)进行了估算。结果表明:各地貌单元土壤碳含量、单位土壤平均碳量、有机碳储量、有机碳丰度指数(R)分布具有山区高于平原区、丘陵区最低的一致性特征。龙门山区、西南山区面积约占全区的42%,土壤有机碳储量约占全区的59%;成都平原区、丘陵区面积占58%,土壤有机碳储量约占全区的41%。单位土壤平均碳量、有机碳储量在不同地貌单元中分布的差异主要与不同地貌单元的土壤有机碳含量有关,此外还可能与成土母质、植被发育情况、土地利用方式有关。  相似文献   

油源对比微量元素地球化学研究进展   总被引：2，自引：0，他引：2  

曹剑  吴明  王绪龙  胡文瑄  向宝力  孙平安  施春华  鲍海娟 《地球科学进展》2012,27(9):925-937

原油中的微量元素地球化学组成可以应用于油源对比,指标可以归纳为3类:①所含元素的聚类分析及其所反映的元素分布总体特征;②不同族、不同类型元素的组成,特别是过渡族金属元素;③稀土元素。但对于哪些微量元素可以应用于油源对比,哪些具有普遍意义,在不同地区是否具有适用性,影响其油源对比应用有效性的因素有哪些,主控因素是什么,仍然不甚清楚,由此导致很多方面的认识还不甚成熟,成功应用的实例相对常规的有机地球化学研究不多。原油中的微量元素主要来源于外部成油和运聚环境,在原油生成和运聚过程中,通过烃—水—岩之间的复杂有机—无机相互作用以金属卟啉螯合物、有机络合物或吸附态的形式聚集于原油中,并且沥青质是原油中微量元素的主要载体,元素组成在此过程中发生分异。此外,原油在自身形成与演化过程中也会发生元素组成的分异,影响因素包括油源母质类型、成熟度、次生变化等。在这些过程中,元素地球化学性质的不同会使原油中的元素组成出现差异,基本不发生/少发生变化的元素即可能是好的油源对比指标,这是应用微量元素进行油源对比的原理和理论基础。  相似文献   

Remediation of saturated Shanghai sandy silt contaminated with p-xylene using air sparging     

Yong-Gui Chen  Wei-Min Ye  Zi-Jun Xie  Bao Chen  Yu-Jun Cui 《Natural Hazards》2012,62(3):1005-1020

Air sparging is an effective technique for the remediation of soil and groundwater polluted by volatile organic compounds. In this paper, this technique was investigated by conducting air-sparging test in the laboratory on the Shanghai sandy silt that was artificially contaminated with p-xylene. A test tank was designed for this purpose. During the air-sparging process, aqueous p-xylene solutions were extracted from the observation holes, and their concentrations were quantified by the spectrophotometric detection method. The mechanism of mass transfer process of p-xylene in the vicinity of sparging well and the remediation of the contaminated groundwater by air sparging were explored. The results showed that the removal zone of the p-xylene was mainly located within a radius of about 20?cm around the air injection well, with 90?% p-xylene removed after 20-day air sparging. Within the initial 5-day sparging, the concentration of p-xylene decreased rapidly in the mass transfer zone. By contrast, in the area far from the injection well, the p-xylene concentration decreased evenly and slowly. Thus, the remediation of contaminated soil and groundwater by air sparging is space?Ctime dependent. For further analysis, the adsorption of silt was taken into account, and the distribution coefficient, K _d , was introduced to the modified Shackleford??s mass transfer model. The comparison between the simulated and measured results indicates that the modified model can satisfactorily describe the p-xylene mass transfer observed in this study.  相似文献   

中国西南山区稻作梯田的时空演化——以苗岭西江镇和加榜乡为例     

余梦  李阳兵  罗光杰  张涵  徐倩  余李敏 《地理研究》2022,41(8):2184-2202

稻作梯田是中国南方山区重要的土地利用方式,分析其时空变化规律,对区域土地资源利用、生态环境保护以及农村农业可持续发展具有重要意义。本文基于多源数据获取苗岭山区西江镇（1977—2020年）和加榜乡（1962—2020年）的土地利用分类图,运用景观指数、空间分析和样带分析等方法,研究稻作梯田时空格局与功能的演化特征,以揭示稻田利用与人地关系演变过程及其特殊性变化。结果表明：① 研究区稻田规模长期稳定发展,但近年整体规模有所缩小,斑块破碎化趋势逐渐凸显。在2000年前稻田分布表现出同时向高、低海拔及微坡至急陡坡扩展,2000年后呈反向收缩趋势,种植强度呈相同的变化规律。② 研究区稻田核密度的空间分布,表现出小规模高密度集聚与大规模中低密度分布并存的格局。自2000年以来,两地稻田核密度以小幅变化为主,有明显的“东北-西南”向分布特性。③ 在生产用地导向阶段,大面积林地转为稻田;在生态-经济复合用地导向阶段,稻田规模保持稳定。④ 聚田比指数显示研究区“人多田少型”占比不断上升,这表明部分地区人地矛盾日渐凸显,以西江镇的变化最为强烈。⑤ 依据“林-田-村-河”四素同构的样带分析,稻田功能经历了“生产-生态、经济”的演变过程,与旅游业发展关系密切。研究结果较全面反映了研究区稻作梯田的时空演化特征,有助于促进山区传统稻田资源优化利用和保护传承,在一定程度上为乡村振兴发展提供借鉴。  相似文献