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71.
72.
叶溪育石煤是湖南省境内一种比较特殊的煤种,其赋矿层位属"下寒武统黑色含矿岩系",主要分布于寒武系下统小烟溪组下段,一般含石煤层3层,个别地段为4-5层。叶溪育石煤矿可采石煤主要为第二层,厚度4.98~9.18m,平均7.49m。该矿石煤分布面积大,层位稳定,连续性较好;原煤发热量3.52~10.23MJ/kg,灰分产率52.12%~74.32%,全硫平均含量1.56%,为中硫、高灰分、低发热量的劣质煤;煤系地层中同时含钒矿体Z1、Z2、Z3,呈似层状、透镜状产出,其中Z1矿体已达中型规模;根据稀土元素地球化学分析,含煤岩系形成于缺氧的还原环境,矿床成因属于生物地球化学沉积矿床。 相似文献
73.
Microbes are believed to play important roles in ecosystem function in many environments. The hot springs of Xiamen Island are close to the Xiamen Sea, and may have some characteristics different from those of inland hot springs. Microbes living in the hot springs of Xiamen may have new characteristics. However, little is known about microbial communities of hot springs close to the Xiamen Sea. A cuhure-dependent survey of microbial population in the Xiamen hot springs was pcrformed by using an approach combining total cellular protein profile identification and 16S rRNA gene sequencing. A total of 328 isolates of bacteria were obtained from liquid and sediment samples from the Xiamen hot springs, including neutrophilie thermophilic bacteria and moderately thermophilic acidophiles. Neutrophilic thermophilic bacteria, which grow at a temperature range of 55-90℃ including Rhodothermus marinus (Strain 1) , Thermus thermophilus (Strain 2), Thermus thiopara (Strain 3) , Geobacillus stearothermophilus(Strain 4) , Geobacillus thermoleovorans (Strain 5) , and Pseudomonas pseudoal-caligenes (Strain 6), were recovered by 2216E plates. Moderately thermophilic acidophiles, which can grow at temperatures above 50℃ and a pH range of 1. 8-3.5 such as Alicyclobacillus acidoterrestris (Strain 8) , Sul-fobacillus acidophilus (Strain 9), and Sulfobacillus thermosulfidooxidans (Strain 10), were isolated on selective solid medium containing sulfur and Fe2+. Among these strains, Rhodothermus marinus, Thermus thermophilus and Geobacillus stearothermophilus are not only thermophilcs, but also halophiles. One bacterium strain (Strain 6) shared 99% nucleotide sequence homology with Pseudomonas pseudoalcaligenes on the 16S rRNA gene se-quence, but was quite different from Pseudomonas pseudoalcaligenes in biological characteristics, suggesting that it may represent a novel thermophilic species. Results indicated that various species of neutrophilic thermophiles and moderately thermophilic acidophiles were widely distributed in the Xiamen hot springs and that Rhodother-mus marinus and Thermus thermophilus dominated the cultivable microbial community. 相似文献
74.
通过航磁、重力异常及数据处理成果的分析和研究,阐述了清原地区深部构造、区域构造、花岗岩体及太古宙变质杂岩的展布特征与金矿成矿之间的关系,指出了该区金矿成矿的远景地段。 相似文献
75.
Tectonic Environments of Cenozoic Volcanic Rocks in China and Characteristics of the Source Regions in the Mantle 总被引:1,自引:0,他引:1
Extensive volcanism is one of the important features of Cenozoic geology in China.Based on temporal-spatial distribution,the volcanism was associated with three major different geological settings:1)the continental rift basalts in Northeast and North China;2)the tension-fault basalts on the continental margins of Southeast China; and 3) the collision-zone high-K volcanics in the Qinghai-Xizang Plateau and its vicinities.The characteristics of “depletion in the south and enrichment in the north“of the China continental mantle are strongly supported by isotopic evidence.The Cenozoic continental cal characters,into the following geochemical provinces:1)the depleted mantle in South China;2)the primary mantle in Northeast and NorthChina; 3)the hybrid and transi-tional mantle in the region of Shandong ,Anhui,Jiangsu and northern Zhejiang;4)the depleted mantle around the Bohai Bay and the Lower Liaohe River;5)the K-metasomatic enriched mantle in the northern part of Northeast China;and 6)the re-cycled enriched mantle in the ancient subduction zone in the Qinghai-Xizang Plateau and its surround-ings.These geochemical characteristics on a regional scale must be a reflection of the nature of lithosphere evolution. 相似文献
76.
JIANG Guoliang ) * YANG Dong ) LIU Yun ) ZHANG Guanghua ) LI Zhongjun ) ZHANG Xinhua ) ) College of Marine Life Sciences Ocean University of China Qingdao P..R.China) Fisheries College Ocean University of China Qingdao P..R.China) Agriculture bureau of Anqiu Anqiu P..R.China 《中国海洋大学学报(英文版)》2003,2(1):62-64
1 Introduction Chinaisboththelargestproducerandthelargestconsumerofchemicalfertilizersintheworld .Since1984 ,Chineseconsumptionofchemicalfertilizerhasincreasedmorethanonetimes ,fromabout 17millionmetrictonsto 35millionmetrictons .However ,dur ingthesameperiod ,theyieldoffoodproductionhasincreasedonlyabout 10 % .Thediscrepancybetweenfertilizerconsumptionandyieldincreasehasindicatedthedrasticdecreaseofthebenefitsofchemicalfertiliz ers .Infact ,theutilizationefficiencyofnitrogenfer tilizerinC… 相似文献
77.
The geochemical variations of mid-Cretaceous lavas across western Shandong Province, China and their tectonic implications 总被引:1,自引:0,他引:1
Major and trace element as well as Sr–Nd isotopic compositions of mid-Cretaceous lavas across western Shandong Province, China
have been studied. These lavas can be generally divided into southern Shandong group (including Pingyi and Mengyin) and northern
Shandong group (including Laiwu and Zouping) based on their geochemistry. The southern group lavas are characterized by extreme
enrichment in LREE, large ion lithophile elements (LILE), and depletion in HFSE along with EMII-like Sr–Nd isotopic compositions,
suggesting that the crustal involvements play a significant role in their petrogenesis. Comparing studies with Fangcheng basalts
reveal that the Triassic continent–continent collision between the Yangtze craton (YC) and the North China craton (NCC), and
subsequent extensive modification of the sub-continental lithospheric mantle (SCLM) beneath the south part of the NCC by silicic
melts released from the subducted Yangtze lower crust, formed an enriched lithospheric mantle which was the source of the
southern Shandong group lavas. In contrast, the northern Shandong group lavas are mildly enriched in LREE and LILE relative
to those of the southern group lavas. The isotope compositions are also distinctive in that the Sr isotopic ratios are very
low. Available geochemical evidence and comparing studies with spatially closed related mafic intrusions suggest that the
SCLM feeding the northern group lavas seems to be linked to carbonatitic metasomatism and changed modal proportion of phlogopite
and clinopyroxene in the mantle rather than subduction-related modifications. The contrasting geochemical characters of the
mid-Cretaceous lavas across western Shangdong suggest that the SCLM of the NCC is spatially heterogeneous in Mesozoic. 相似文献
78.
纹理特征在多光谱遥感影像分类中的应用 总被引:1,自引:3,他引:1
提出了基于灰度共生矩阵的多光谱影像纹理分析的方法,实现了利用k-mean聚类算法对多光谱影像进行分类,比较了各种不同的分类结果。 相似文献
79.
针对BP人工神经网络具有易陷入局部极小等缺陷,提出了将遗传算法与神经网络结合,同时优化网络结构的权值与阈值的思想,建立了基于遗传算法的围岩松动圈预测的神经网络模型。用该模型对巷道围岩松动圈厚度进行了预测并与BP预测结果相比较。结果表明,该遗传神经网络模型可靠,预测精度高,用来对围岩松动圈厚度进行预测是有效的和可行的。 相似文献
80.
亚急性脑内血肿CT诊断 总被引:1,自引:1,他引:0
本文收集了15例亚急性脑内血肿病例,就其病理演变,CT表现作了具体分析,指出亚急性脑内血肿CT诊断应密切结合临床,特殊病例需做MR确诊。 相似文献