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211.
策划是高校学报编辑的现实选择,策划能力是现代学报编辑的基本素质。在高校学报策划中,理念策划是学报办刊的根本指导和制约,学术策划是学报保持学术品位的关键,主编策划是学报编辑策划的主体,稿源策划是学报生存和发展的保证。 相似文献
212.
Discussion of gas enrichment mechanism and natural gas origin in marine sedimentary basin,China 总被引:4,自引:0,他引:4
《科学通报(英文版)》2007,52(Z1)
There are abundant natural gas resources in Chinese marine sedimentary basin. The exploration hot shots of natural gas are the Palaeozoic marine strata here in recent years, and several large scale gas fields have been discovered. Chinese Palaeozoic high-post matured and coal measure hydrocarbon source rocks are mainly prone to gas generation in the present. This research considered that gas source rocks and TSR are the key cause of gas enrichment of marine strata. High-quality argillaceous and coal measure hydrocarbon rocks are distributed widely in the Palaeozoic marine strata, which have been in highly matured phase in the present. The argillaceous source rock generally contains various sulfates that could accelerate crude oil cracking to gas for TSR occurrence, and coal measure source rock mainly generates gas, so Chinese marine basin gives priority to accumulating gas. Marine strata have not founded oil reservoirs in the Sichuan Basin and Ordos Basin, and they consist mainly of dry gas. Marine natural gases are the mixed gases of oil cracking gas and coal-formed gas in a general way, oil cracking gases contain usually some H2S and CO2. Hydrocarbon carbon isotopes are very complicated, and methane and ethane isotopic values bear apparent reversal caused by thermal evolution and mixing among different genetic types of natural gas. Coal-formed gases are the main component of Chinese marine natural gas. The Upper Permian of the Sichuan Basin and the Carboniferous-Permian of the Ordos Basin coal measure hydrocarbon source rock present large hydrocarbon generation potential, which are the prospecting highlight of marine natural gas hereafter. Oil cracking gas exploration will be paid much attention to in the Tarim Basin because of the lack of coal measure hydrocarbon source rock. 相似文献
213.
214.
HU WenXuan SONG YuCai CHEN XiaoMing TAO MingXin ZHANG LiuPing 《科学通报(英文版)》2007,52(3):380-387
This study presents noble gaseous data of the corundum megacrysts from the Cenozoic basalts in Changle, Shandong Province, eastern China. It is known that no noble gaseous data of corundum megacryst have been documented before. The 3He/4He ratios (1.13-7.37 Ra) of the corundums from Changle vary from atmosphere to MORB values; the 20Ne/22Ne (9.67-10.75) and 21Ne/22Ne (0.0280-0.0372) data define two linear trends on Ne three-isotope diagram, respectively, along the MFL and the correlation line between atmosphere and MORB; the 38Ar/36Ar (0.177-0.194) ratios, the 40Ar/36Ar (280.9 -404.2) ratios and the 128-136Xe/132Xe ration with obvious 129Xe excess are generally higher than at-mospheric component, but the 40Ar/36Ar ratios are much closer to atomospheric ratio. The isotopic compositions of noble gases (particularly for He and Ar) of the corundums are similar to those of py-roxene, anorthoclase megacrysts, and mantle-derived xenoliths from this area, and those of man-tle-derived xenoliths from several areas in eastern China. Therefore, the noble gases trapped in the corundums probably are from mantle source, representing a ‘mixed fluid' produced by the interaction between the lithospheric mantle and fluids releasing from the convective plate. Both the noble gas isotopic compositions and the oxygen isotopic compositions of the solid corundums are not the characteristics of crustal source. These suggest that the corundums crystallized from mantle-derived magmas with minimal crustal contamination. 相似文献
215.
Recent temperature increase recorded in an ice core in the source region of Yangtze River 总被引:3,自引:4,他引:3
KANG ShiChang ZHANG YongJun QIN DaHe REN JiaWen ZHANG QiangGong Bjorn GRIGHOLM Paul A. MAYEWSKI 《科学通报(英文版)》2007,52(6):825-831
Interests on climate change in the source region of Yangtze River have been raised since it is a region with the greatest warming over the Tibetan Plateau (TP). A 70-year history of precipitation δ~(18)O has been recovered using an ice core record retrieved in a plat portion of the firn area in the Guoqu Glacier (33°34′37.8″N, 91°10′35.3″E, 5720 m a.s.l.), Mt. Geladaindong (the source region of Yangtze River), in November, 2005. By using a significant positive relationship between ice core δ~(18)O record and summer air temperature (July to September) from the nearby meteorological stations, a history of summer air temperature has been reconstructed for the last 70 years. Summer temperature was relatively low in 1940s and high in 1950s to the middle of 1960s. The lowest temperature occurred in the middle of 1970s. Temperature was low in 1980s and dramatically increased since 1990s, keeping the trend to the begin-ning of the 21st century. The warming rate recorded in the ice core with 0.5℃/10 a since 1970s is much higher that that in the central TP and the Northern Hemisphere (NH), and it becomes 1.1℃/10 a since 1990s which is also higher than these from the central TP and the NH, reflecting an accelerated warm-ing and a more sensitive response to global warming in the high elevation region. 相似文献
216.
LIU Yuan SHAO Min 《科学通报(英文版)》2007,52(9):1274-1281
Black carbon is a by-product of incomplete combustion of carbon containing fuels. It can alter atmospheric radiation property and make adverse impacts on human health. The energy consumption in Beijing City depends largely on coal burning. Recently, Beijing City has been performing the municipal energy structure adjustment as a tool for air pollution abatement, aiming at the air quality goal for the Beijing 2008 Olympic Games. Based on Beijing energy use data in 2000, combined with emission factors of major sources of black carbon, the emission of black carbon in Beijing City is estimated to be 7.77 Gg. Coke, raw coal and biomass as non-commercial energy are the main contributors to municipal black carbon emissions. Based on Beijing energy planning in the year 2008, the emission of black carbon in 2008 will be 2.97 Gg if the contribution from biomass is not taken into account. Assuming that the black carbon emission from rural biomass in 2008 is the same as that in 2004, the biomass burning will be the largest emitter of black carbon to Beijing City in 2008. 相似文献
217.
李慧彬 《科技情报开发与经济》2007,17(10):195-196
从源路由算法、分布式路由算法和层次型路由算法3个方面分析了现有Qos组播路由算法,介绍了相关算法的基本思想,并探讨了今后的研究方向。 相似文献
218.
为向冷中子源装置氢系统提供17.5K的低温冷源,设计了逆布雷顿循环的液氮预冷模式和4种膨胀机预冷模式,并对这5种循环模式进行热力分析和[火用]分析,获得了各循环模式下的主要热力参数并分析比较了各自的热力性质.结果表明:带液氮预冷和前置式并联膨胀机预冷2种模式的热力性能最好,[火用]效率最高;对于膨胀机预冷循环,并联模式优于串联模式,前置式优于后置式.循环系统[火用]损失部位主要在压缩机、膨胀机和换热器,减小这3部分[火用]损失的途径有以下方面:改善循环,减小系统氦的质量流量;提高压缩机的等温效率、膨胀机的等熵效率;改善换热器的内部温度、温差、压力分布及物流分配.本研究为中国先进研究堆冷中子源氦制冷系统的设计提供了数值基础。 相似文献
219.