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471.
472.
Kerogen plays an important role in shale gas adsorption, desorption and diffusion. Therefore, it is necessary to characterize the molecular structure of kerogen. In this study, four kerogen samples were isolated from the organic-rich shale of the Longmaxi Formation. Raman spectroscopy was used to determine the maturity of these kerogen samples. High-resolution transmission electron microscopy (HRTEM), 13C nuclear magnetic resonance (13C NMR) , X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy were conducted to characterize the molecular structure of the shale samples. The results demonstrate that VReqv of these kerogen samples vary from 2.3% to 2.8%, suggesting that all the kerogen samples are in the dry gas window. The macromolecular carbon skeleton of the Longmaxi Formation kerogen is mainly aromatic (fa’=0.56). In addition, the aromatic structural units are mainly composed of naphthalene (23%), anthracene (23%) and phenanthrene (29%). However, the aliphatic structure of the kerogen macromolecules is relatively low (fal*+falH=0.08), which is presumed to be distributed in the form of methyl and short aliphatic chains at the edge of the aromatic units. The oxygen-containing functional groups in the macromolecules are mainly present in the form of carbonyl groups (fac=0.23) and hydroxyl groups or ether groups (falO=0.13). The crystallite structural parameters of kerogen, including the stacking height (Lc=22.84 ?), average lateral size (La=29.29 ?) and interlayer spacing (d002=3.43 ?), are close to the aromatic structural parameters of anthracite or overmature kerogen. High-resolution transmission electron microscopy reveals that the aromatic structure is well oriented, and more than 65% of the diffractive aromatic layers are concentrated in the main direction. Due to the continuous deep burial, the longer aliphatic chains and oxygen-containing functional groups in the kerogen are substantially depleted. However, the ductility and stacking degree of the aromatic structure increases during thermal evolution. This study provides quantitative information on the molecular structure of kerogen samples based on multiple research methods, which may contribute to an improved understanding of the organic pores in black shale. 相似文献
473.
椒江口潮间带大型底栖动物群落beta多样性分析 总被引:2,自引:0,他引:2
于2007年10月在椒江口共布设6条潮间带采样断面,每条断面在中潮带上区、中区、下区和低潮区各设1站位进行大型底栖动物采样。分析了不同采样站位数与大型底栖动物种数的关系,选用Wilson-Shmidabeta多样性测度方法,对以下3种空间环境梯度下大型底栖动物群落beta多样性进行了研究:(1)断面内垂直环境梯度;(2)河流到海洋的环境梯度;(3)河口两岸间的距离梯度。分析了不同采样站位数对群落beta多样性指数的影响,结果显示:(1)随着采样站位数的增加,物种数呈增加趋势但增速渐慢,同时beta多样性指数呈下降趋势;(2)不同的潮区间隔下的be-ta多样性指数均有显著差异;(3)在北岸和南岸,随着断面间距的增加beta多样性指数均呈升高趋势,而且与各断面的沉积物粒度、油类含量呈显著相关;(4)椒江口为喇叭形河口,随着河口两岸断面距离的增加beta多样性指数呈升高趋势。 相似文献
474.
采用随机扩增多态性DNA技术,对花鲈(Lateolabrax japonicus)皮肤溃疡病抗性和敏感两个群体的遗传多样性进行了研究.从100个10 bp随机引物中筛选出25个随机引物,在两个群体中共扩增了326个位点,抗性群体多态住点比率为44.24%,遗传变异度为0.123 7,Shannon多样性值为0.1149,分别比敏感群体高3.87%,5.82%和2.68%,表明花鲈抗病群体比敏感群体具有更丰富的遗传多样性.25条随机引物中,7条引物在两群体中的扩增结果存在差异,其中S11,S15,S4,S414,S416,S9在抗性群体的扩增结果比敏感群体多1个多态住点,S52多2个多态位点.在这8个特异多态位点中,S52-1,S4-1,S414-6,S9-2在敏感群体中全部出现,呈单态性;S15-5,S11-6,S416-6,S52-5只在抗性群体中出现,出现频率分别为38.5%,30.8%,23.1%和23.1%.说明这8个位点在两群体中存在较大的差异.研究表明,花鲈皮肤溃疡病在遗传上是比较复杂的,并不是简单地与某个遗传标记有关,可能与多个遗传因素相关. 相似文献
475.
共转换点道集的抽取是三维转换波数据处理的重要环节,道集抽取的正确与否受多种因素影响,其中地层倾角的变化能够引起共转换点道集的抽取误差,表现在炮点、检波点的数量与位置的错选。以地层倾向120°,某转换点垂向深度600m,纵横波速度分别为2 500m/s、1 250m/s的单层倾斜模型为例,利用姚陈提出的倾斜界面三维转换波CCP位置计算方法,对地层倾角分别为0°、5°、20°、30°时的炮点、检波点进行统计,确定其对该转换点的贡献情况,结果表明:倾角CCP抽取方法与目前常用的水平界面假设算法计算出的炮点、检波点分布存在很大差异,忽略倾角因素影响将导致不正确的道集叠加,给后期解释带来极大误差。 相似文献
476.
37°N断面营养盐和溶解氧的四季分布特征及变化 总被引:1,自引:1,他引:0
以2006年7月至2007年10月期间,4个季节的4个航次对37°N断面的调查资料为依据,分析并讨论了该断面四季生源要素的分布特征以及变化趋势。结果表明:该断面受黄海冷水团和陆源输入的影响,东西两侧的生源要素及温盐特征明显不同。夏季断面东侧由于受到冷水团的控制,底层出现明显的低温、高盐、高营养盐和高溶解氧的特征,并且跃层明显;西侧浅水区的温盐及生源要素的变化则相对均匀。冬季由于温跃层的消失,上下水体混合均匀,故而温盐及生源要素的垂直分布趋于均匀,断面西侧由于受到陆源输入的影响营养盐的浓度明显较东侧高。春季是增温降盐,营养盐逐渐消耗,东侧温跃层逐渐形成的过程;而秋季则恰恰相反。 相似文献
477.
478.
YU Lu SUN Fengyue LI Bile LI Liang LI Ruihua JIANG Hefang WANG Fei SHAO Ji SHEN Dali 《世界地质(英文版)》2017,20(2)
The study presents the results of U-Pb dating of zircons and whole-rock geochemical analyses of a syenogranite located in the western Niubiziliang area,China with the aim of determining its formation time,petrogenesis and the regional tectonic setting. Zircons within the syenogranite are euhedral-subhedral and display rhythmic growth zoning,indicating a magmatic origin. Zircon U-Pb data obtained by LA-ICP-MS indicate the syenogranite formed in the Late Permian (260.7±1.5 Ma). The w(SiO_2) of syenogranites is 70.82%--73.59%,w(Al_2O_3) is 13.49%--14.82%,and w(Na_2O + K_2O) is 7.85%--8.52%,and yield K_2O/Na_2O ratios of 1.06--1.26. Therefore,the syenogranites belong to the high-K calc-alkaline and metaluminous (A/CNK 1,A/NK 1) series which display I-type granites similarly. The syenogranites also show the geochemical characteristics of volcanic arc rocks,being enriched in large-ion lithophile elements (LILEs; K,Rb) and light rare-earth elements (LREEs; La,Ce,Sm,Nd),but depleted in high field strength elements( HFSEs; Ta,Nb,P,Ti). On the whole,trace element ratios are close to the mean of the Earth's crust,indicating a lowercrust magma source. The low Sr (161--214) ×10~(-6) and Yb (1.08--1.80)×10~(-6) concentrations indicate that plagioclase and hornblende are residual mineral phases in the source. The regional geology and whole-rock geochemistry suggest that the formation of the syenogranites was related to subduction of the Zongwulong Ocean crust,and the north margin of Qaidam Block during the Late Permian was in an active continental margin tectonic setting. 相似文献
479.
An evolutionary economic geography perspective on types of operation development in West Lake,China 总被引:1,自引:0,他引:1
The types of operation play a key role in facilitating tourism consumption and economic development in a tourism destination. By adopting evolutionary economic geography theory, the paper analyzes the types of operation in West Lake Scenic Area from 1978 to 2013. First, an evolution process consisting of four stages is underpinned, and they are: the new establishment stage, the preliminary development stage, the speedup development stage, and the stabilized maturity stage. Specifically, the distinct characteristics associated with operation types are compared and evaluated at different stages throughout the process. The evolution trees are introduced to scrutinize types of operation development. The results of evolution trees demonstrate the substantial increase in both numbers and types. Second, by applying GIS spatial analysis, the paper also analyzes the spatial evolution characteristics on the types of operation, and the results unveil the co-existence of centripetal and centrifugal forces: the processes of spatial agglomeration and spatial dispersion. More specifically, we recognize the spatial process includes the emergence of node and concentration(1978–1995), the sparse distribution and intensity reduction(1996–2002), the patchy distribution and spatial agglomeration intensification(2003–2008), the dispersed distribution and core area agglomeration(2009–2013). Lastly, path dependence on resource endowment, government and market innovation, knowledge learning and spillover can reasonably explain the types of operation evolution. In conclusion, the evolutionary economic geography theories provide new theoretical and empirical perspectives for tourism policy analysis. At the same time, our comprehensive evidences impart more comprehensive insights and offer useful managerial and policy implications. 相似文献
480.
Xianhong Meng Xiaoli Shi Jie Kong Sheng Luan Kun Luo Baoxiang Cao Ning Liu Xia Lu Xupeng Li Kangyu Deng Jiawang Cao Yingxue Zhang Hengheng Zhang 《中国海洋大学学报(英文版)》2017,16(5):863-872
To elucidate the molecular response of shrimp hepatopancreas to white spot syndrome virus (WSSV) infection, microarray was applied to investigate the differentially expressed genes in the hepatopancreas of ‘Huanghai No. 2’ (Fenneropenaeus chinensis). A total of 59137 unigenes were designed onto a custom-made 60K Agilent chip. After infection, the gene expression profiles in the hepatopancreas of the shrimp with a lower viral load at early (48–96 h), peak (168–192 h) and late (264–288 h) infection phases were analyzed. Of 18704 differentially expressed genes, 6412 were annotated. In total, 5453 differentially expressed genes (1916 annotated) expressed at all three phases, and most of the annotated were either up- or down-regulated continuously. These genes function diversely in, for example, immune response, cytoskeletal system, signal transduction, stress resistance, protein synthesis and processing, metabolism among others. Some of the immune-related genes, including antilipopolysaccharide factor, Kazal-type proteinase inhibitor, C-type lectin and serine protease encoding genes, were up-regulated after WSSV infection. These genes have been reported to be involved in the anti-WSSV responses. The expression of genes related to the cytoskeletal system, including β-actin and myosin but without tubulin genes, were down-regulated after WSSV infection. Astakine was found for the first time in the WSSV-infected F. chinensis. To further confirm the expression of differentially expressed genes, quantitative real-time PCR was performed to test the expression of eight randomly selected genes and verified the reliability and accuracy of the microarray expression analysis. The data will provide valuable information to understanding the immune mechanism of shrimp’s response to WSSV. 相似文献