对目前煤炭资源勘查与开发利用中存在的一些问题的思考     

高洪烈 《中国煤炭地质》2010,(11):67-69

煤炭资源勘查和开发利用中,存在着一些值得思考与探讨的问题,如资源储量划分、勘查区境界的依据、资源分类与勘查程度的关系、回采率问题、共伴生矿床的勘查、煤层气勘查与瓦斯抽放、水文地质工程地质及开采技术条件勘查、采矿废弃物资源化、基础性地质工作的管理等。针对上述问题,结合煤炭资源勘查实践,提出了相应的建议。  相似文献   

海洋一号卫星水色水温扫描仪红外信息获取          下载免费PDF全文

范文龙  黄小仙  傅雨田 《遥感学报》2022,26(8):1589-1601

对海温分布与变化的探测是海洋一号卫星主载荷水色水温扫描仪（简称水色仪，COCTS）的主要任务之一。考虑到对海冰和海洋上空台风等气象要素的同时探测，实际水温探测通道的动态范围要求涵盖200—320 K的温度区间。由于某些洋面区域微弱温度的变化将会导致严重天气灾害的发生，因此海温探测通道还需满足探测灵敏度与定量化的精度要求。本文旨在依据技术指标要求，设计水色仪红外通道的信息获取电路，包括对探测器微弱信号进行放大的前置放大电路，消除基础电平以提高动态范围的交流放大器，以及实现信号的直流恢复与动态范围调整的通道放大电路。基于对所使用的光导型红外探测器工作机理的研究，结合水色仪的系统组成与特性，为确保同时满足高动态范围与高灵敏度这一对相互矛盾的指标要求，通过理论分析计算、电路仿真等方法，确定各级放大电路的形式及参数。在真空环境模拟实验室对水色仪的系统性能进行测定，以验证信息获取电路设计的合理性。在实验室进行的红外辐射定标结果表明和在轨测试结果均表明，水色仪两个红外通道的动态范围和噪声等效温差（NETD）均能较好的满足技术指标要求。红外通道能够实时跟踪星上黑体信号随时间与周围环境的变化，可据此来对红外通道的定标系数进行即时修正，从而达到预期的在轨实时辐射定标的目的，为定量化反演海温奠定了基础，并能获取且制作出高质量的全球海温产品。  相似文献   

Causes of variation in crystal morphology in metamorphogenic pyrite deposits of the Cameros Basin (N Spain)     

J. Alonso‐Azcrate  M. Rodas  L. Fernndez‐Díaz  S.H. Bottrell  J. R. Mas  S. Lpez‐Andrs 《Geological Journal》2001,36(2):159-170

The low‐grade metasediments of the Cameros Basin, northern Spain, host a number of deposits of spectacular quality pyrite mineralization. These formed during regional metamorphism and the pyrite crystals exhibit a wide range of morphologies. On the basis of pyrite crystal habit, the deposits can be classified into two groups: Group I comprises deposits with cubic, elongated or platy crystals; Group II comprises deposits characterized by pyritohedra and cubo‐pyritohedra with striated faces, along with blocky crystals and fine‐grained aggregates. Group I deposits are formed in sequences dominated by meandriform fluviatile sediments, while Group II is hosted by deltaic plain and lacustrine metasediments. Temperature differences between deposits and As content are possible causes of the different pyrite morphologies in the deposits, but no significant variation exists between the two groups for either factor. Comparison with experimentally grown pyrite crystals suggests that Group I deposits have morphologies indicative of lower degrees of pyrite supersaturation than pyrite crystals in Group II deposits. The sedimentary facies hosting Group II deposits provides a greater availability of sedimentary sulphur (pyrite and sulphates). Moreover, reactions involving sulphate during metamorphism may have modified fluid chemistry, which would also act to produce higher degrees of pyrite saturation in fluids derived from the sulphate‐rich deltaic plain and lacustrine metasediments hosting the Group II deposits. This hypothesis is confirmed by sulphur isotope data on the pyrites, which show a larger component of³⁴S‐enriched sulphate‐derived sulphur in these deposits. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

The Early–Middle Triassic Supervolcano in the Yangtze Block,South China and associated obstacles to biotic recovery     

《地学前缘(英文版)》2024,15(1):101694

The end–Permian mass extinction was one of the major global crises spanning the entire Early Triassic or longer. Eruptions of volcanos were one of the factors that delayed the biotic recovery after this event. Supervolcano eruptions can cause catastrophic effects on global environment, climate, and life. Here we investigate the tuff layers from Early–Middle Triassic boundary in the Yangtze Block and identify a supervolcano eruption event. The zircon U–Pb ages of the section–Langdai, section–Daijiagou and section–Longmendong tuff samples are 247.1 ± 1.9 Ma, 247.6 ± 2.0 Ma and 247.7 ± 1.7 Ma, respectively. These ages mark the Olenekian–Anisian boundary. The zircon grains from the tuff layers have negative ε_Hf(t) (−15.3 to −0.8), two–stage Hf model (T_DM2) ages (1.7 to 2.2 Ga) and display high–δ¹⁸O values (mostly > 10‰). Clay minerals and quartz dominate the rock composition. The whole rock compositions show that the tuff layers were derived from magma of intermediate to felsic composition, which formed by the remelting of Paleoproterozoic materials of continental crust. The volcanic eruption site is located in the Jinshajiang–Ailaoshan–Song Ma suture zone in the southwestern margin of the Yangtze Block. A combination of the closure of the Paleo–Tethys Ocean Basin and the collision of the Indochina Block and South China contributed to the eruption, which was a supervolcano eruption under the active continental margin arc settings. We speculate that this supervolcano eruption might have contributed to the delayed biotic recovery after the end–Permian mass extinction.  相似文献   

Spatial differentiation and driving factors of economic resilience in the Yangtze River Economic Belt,China北大核心CSCD     

Yuan F.  Xiong X.  Xu Z.  Yu L. 《地理科学进展》2023,(2):249-259

The 2008 global financial crisis had a huge impact on China's real economy, and inspecting the imbalance and differentiation mechanism of the regional economic recovery process after the crisis is conducive to providing a reference for promoting regional high-quality and sustainable development. Based on the multidimensional resilience measurement framework, this study comprehensively investigated the dynamic evolution process of economic resilience in the Yangtze River Economic Belt after the 2008 global financial crisis, and focused on the temporal variation characteristics and spatial differentiation patterns of resistance and resilience. On this basis, the fixed effect panel regression model was used to analyze the role of factors such as industrial development status, regional development foundation, level of opening up, government management level, and innovation environment on economic resilience. The study found that at the overall level, the resistance of the Yangtze River Economic Belt after the impact showed a trend of first rising and then declining and the overall performance was high, but the resilience showed a trend of decline-rise-decline and the overall performance was low. The fluctuations in export resistance and resilience were much greater than the fluctuations in the dimensions of GDP, industry, consumption, and employment. Regression models showed that diversity and related diversity and regional innovation capabilities, although limited in the process of resisting risks in the early stage of the crisis, were conducive to the rapid regional resumption of growth after the crisis, areas with strong government management capabilities may hinder economic recovery to a certain extent, and the ability to open up to the outside world has no significant impact on resistance and resilience. © 2023, Editorial office of PROGRESS IN GEOGRAPHY. All rights reserved.  相似文献