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971.
高煤级煤的煤层气开发潜力——以沁水煤田为例   总被引:7,自引:0,他引:7  
通过分析研究山西省沁水煤田的煤层气地质条件和储层特征,结合煤层气开发试验结果,对无烟煤等高煤级煤的煤层气资源开发潜力进行了评价。结果表明:无烟煤等高煤级煤只要煤储层特征参数组合匹配良好,尤其是在较简单的构造条件下,煤体结构完整,煤中裂隙网络较发育且保存较好,煤储层渗透率较高,煤层气资源开发就具有良好的前景。   相似文献   
972.
河南省缺水山区的基本找水模式   总被引:3,自引:2,他引:1  
将系统理论分析方法运用到找水实践中,将水文地质方法与综合物探方法紧密结合,综合考虑各种因素,初步建立了河南省灰岩缺水山区的基本找水模式。它体现了缺水山区地下水赋存的地质-水文地质环境,反映了缺水山区地下水富集的基本特征,是对缺水山区地下水运移规律和赋存特征的高度概括。并在具体找水实践中予以初步应用,取得了较好的效果。   相似文献   
973.
沙埋是沙漠铁路的重要病害形式之一。它是沙漠铁路在运营中造成缓行、停车甚至脱轨的重要原因。我们采用过多种防沙措施, 积累了许多经验, 如: 覆盖沙面、设置沙障、挖截沙沟、固沙造林等。在这些措施中, 以固沙造林效果最好, 具有长期效益, 是治沙的根本途径, 而其它措施只不过是临时性办法, 且要配合使用。  相似文献   
974.
转鲑鱼生长激素基因酵母菌发酵特性的研究   总被引:2,自引:1,他引:1  
张培军、Ball等研究表明,外源性生长激素通过注射或浸泡的方法可加快鱼的生长[1]。根据Mclean1987年、Shunsuke等1993年研究发现鱼类后肠具有吸收部分生长激素进入血液循环的特点,本研究室将鲑鱼生长激素基因克隆进无毒无害的酵母菌中,利用可控制的诱导条件,培养出含鲑鱼生长激素的酵母菌,直接掺入饵料,使生长激素通过消化道吸收,以促进鱼的生长。Jacqueline等1989年指出,由于携带外源基因的酵母菌与普通酵母菌的培养要求不同,既要促使菌体快速生长又要保证外源基因的表达,本研究的目的在于选择适宜的培养条件,实现转基因酵母菌的高密度培…  相似文献   
975.
The pre-Cenozoic northern South China Sea(SCS) Basin basement was supposed to exist as a complex of heterogeneous segments, divided by dozens of N-S faulting. Unfortunately, only the Hainan Island and the northeastern SCS region were modestly dated while the extensive basement remains roughly postulated by limited geophysical data. This study presents a systematic analysis including U-Pb geochronology, elemental geochemistry and petrographic identification on granite and meta-clastic borehole samples from several key areas. Constrained from gravity-magnetic joint inversion, this interpretation will be of great significance revealing the tectono-magmatic evolution along the southeastern margin of the Eurasian Plate. Beneath the thick Cenozoic sediments, the northern SCS is composed of a uniform Mesozoic basement while the Precambrian rocks are only constricted along the Red River Fault Zone. Further eastern part of the northern SCS below the Cenozoic succession was widely intruded by granites with Jurassic-to-early Cretaceous ages. Further western part, on the other hand, is represented by meta-sedimentary rocks with relatively sporadic granite complexes. To be noted,the western areas derived higher-degree and wider metamorphic zones, which is in contrast with the lowerdegree and narrower metamorphic belt developed in the eastern region. Drastic collisions between the Indochina Block and South China continent took place since at least late Triassic, resulting in large-scale suturing and deformation zones. At the westernmost part of the northern SCS, the intracontinental amalgamation with closure of the Meso-Tethys has caused fairly stronger and broader metamorphism. One metamorphic biotite granite is located on the suturing belt and yields a Precambrian U-Pb age. It likely represents the relict from the ancient Gondwana supercontinent or its fringes. Arc-continental collision between the Paleo-Pacific and the southeast China Block, on the other hand, results in a relatively narrow NE–SW trending metamorphic belt during the late Mesozoic. Within the overall geological setting, the Cenozoic SCS oceanic basin was subsequently generated from a series of rifting and faulting processes along the collisional-accretionary continental margin.  相似文献   
976.
Cities based on coal resources have increasingly important social and economic roles in China. Their strategies for sustainable development, however, urgently need to be improved, which represents a huge challenge. Most observers believe that the continued progress of these cities relies on the optimization of scientific adaptive management in which social, economic, and ecological factors are incorporated. A systems perspective that combines policies, management priorities, and long-term policy impacts needs to be applied. To date, however, such an approach has not been adopted, which means it is difficult to implement adaptive management at the regional scale. In this study, we used various situations to develop a multiple adaptive scenario system dynamics model. We then simulated a range of policy scenarios, with Ordos in the Inner Mongolia Autonomous Region as a case study. Simulation results showed that the current strategy is not sustainable and predicted that the system would exceed the environmental capacity, with risks of resource exhaustion and urban decline in 2025–2035. Five critical policy variables, including the urban population carrying capacity, rates of water consumption and water recycling, and expansion of urban land cover, were identified during sensitivity analysis. We developed and compared six socio-economic scenarios. The urban area, represented by the urban population density, seemed to transition through five different stages, namely natural growth, rapid growth, stable oscillation, fading, and rebalancing. Our scenarios suggested that different policies had different roles through each stage. The water use efficiency management policy had a comprehensive far-reaching influence on the system behavior; land urbanization management functions dominated at the start, and population capacity management was a major control in the mid-term. Our results showed that the water recycling policy and the urban population carrying capacity were extremely important, and both should be reinforced and evaluated by the local governments.  相似文献   
977.
The Bohai Bay and Hehuai (southern North China) rift basins in the eastern part of the North China Craton are south-north-adjacent. They have shown synchronous evolutionary processes, and possess generally identical superficial and shallow structural characteristics as well as similar basin areas. However, there is a large difference in the richness of oil resources between the two basins. The Bohai Bay Basin has extremely abundant oil reserves, while commercial oil reserves have not been found in the Hehuai Basin. The deep tectonic structures, magmatic activities, and modern and paleogeothermal fields of the two basins are significantly different. Compared with the Hehuai Basin, the Bohai Bay Basin has a thinner crust and more complex structure with multiple low-velocity layers. It is also characterized by intense magmatic activity, high modern and paleogeothermal fields, frequent seismic activity, and active deep interactions, small effective elastic thickness of the isotropic lithosphere, and shorter balanced transformation wavelength of the lithosphere with a high likelihood of local compensation. The Hehuai Basin has a simple deep structure and homogeneous crustal composition, with a high likelihood of regional compensation. The characteristics of the deep structures mentioned above are generally similar to those of the southern part of the stable Ordos Basin, except for the smaller crust thickness. This indicates the presence of differences in Mesozoic destruction between the southern and northern zones in the eastern part of the North China Craton. The northern zone was subjected to significant destruction, while the southern zone was subjected to modifications, primarily in the form of local changes in the structures and/ or properties of the crust or lithospheric mantle, with the overall structure and stability of the craton kept intact. The formation of high-quality source rock is primarily influenced by the abnormal flourishment of organisms in water bodies during the syndepositional period, and is also strongly associated with the high geothermal setting of basins and nutrients from hydrothermal solutions and volcanoes. In other words, it is mainly controlled by deep processes and deep-major fault activity. The differences in the deep structures and modern and paleo geothermal fields of the two basins correspond to the difference in richness of oil resources, suggesting that there is an important internal or causal relationship between the two aspects. This viewpoint coincides with the conditions and environments required for the development of high-quality source rock in hydrocarbon-rich basins (sags) in China and other countries, and is evidenced by the modern lake basin of the East African Rift. A new hydrocarbon generation model is proposed in this work: petroleum is a comprehensive product of the integration of bioenergy, thermal energy, and other related energies (such as chemical and kinetic energy) and their interactions; the degree of richness of petroleum is generally controlled by the regional tectonic structure, thermal environment, and deep processes; nonmarine basins or depressions with abundant resources are closely related to active deep processes, intense exchange of material between the deep and shallow layers, participation of external hydrocarbons, and energy integration and conversion.  相似文献   
978.
李雨竹  贾磊  张弥  肖薇  张圳  包恒鑫  葛培  王伟  吕恒  万梓文 《湖泊科学》2023,35(5):1808-1821
湖泊“皮肤效应”指表面温度与表层水温的差异,量化“皮肤效应”并分析其影响因素有助于理解湖泊物理、化学、生物和生态过程对气候变暖的响应。本文基于太湖中尺度通量网2011—2020年水温梯度、辐射四分量和小气候观测数据,定量分析了在不同时间尺度和不同天气条件下“皮肤效应”的差异及其影响因素。结果表明,太湖暖“皮肤效应”在15:00—16:00最强,可达1.95℃;冷“皮肤效应”在7:00—8:00最强,达-0.50℃。“皮肤效应”强度春季最强,夏季最弱。因此,无法用表层水温观测值直接验证卫星午后过境反演得到的太湖湖面温度,其偏差可达2℃,尤其在春季。年际尺度上,太湖表面温度上升速率为0.14℃/a,与同期气温上升速率相当,表层水温上升速率为0.12℃/a。使用遥感反演的表面温度表征的太湖升温速率会比传统的表层水温观测结果快0.02℃/a。晴天小风时暖“皮肤效应”最强,为1.64℃;阴天大风时“皮肤效应”最弱,仅为0.32℃。相较于太阳辐射,风速对太湖水温“皮肤效应”的影响更大,风的扰动是影响太湖水温“皮肤效应”的首要因素。此外,基于10年观测数据建立了适用于太湖水温“皮肤效应”的风速参数化...  相似文献   
979.
梁威  刘凌  潘沛 《湖泊科学》2007,19(6):710-717
农业非点源污染研究是当前环境问题研究领域的重点和难点.目前而言土槽尺度下非点源模型的研究较少.利用大型土槽和人工降雨装置来模拟无植被坡地单次降雨过程地表径流中硝态氮迁移过程.在此基础上,适当选取ANSWERS-2000的子模块建立起具有一定机理的适用模型,来研究土槽尺度下无植被坡地单次降雨过程地表径流中硝态氮迁移过程.经过三次实验验证,模拟的径流总量误差在4%-15%之间,CP'A在0.7-12之间;模拟的硝态氮总量误差的绝对值在9%-17%之间,CP'A在0.6-1.1之间.结果显示降雨径流、硝态氮浓度模拟结果与实际观测值有较好的一致性,模型模拟效果较好,模型可用于该尺度下硝态氮迁移量计算,具有一定的研究参考价值.  相似文献   
980.
2017年4月21日中国大陆出现地磁低点位移异常,异常出现后43天,于6月3日在低点位移分界线附近发生阿拉善左旗5.0级地震。文中采用克里格方法对中国大陆低点时间数据进行插值处理,获取地磁异常的4月21日和正常的4月7日Z分量低点时间等值线,结果显示:①异常日期间蒙宁陕交汇处存在低点时间等值线高梯度区,地震发生于高梯度区域边缘;②若以低点时间13 h的等值线作为低点位移分界线,则该分界线穿过震中位置;③异常日期间,震中距500 km范围以内分界线两侧台站Z分量日变形态差异性大,存在显著的分区特征。  相似文献   
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