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11.
The genetic diversity of both wild and reared Pseudosciaena crocea (Richardson) col-lected from Guan-Jing-Yang in Ningde, China in May 1999 was investigated by random amplified poly-morphic DNA (RAPD) in the present study. The polymorphism and mean difference of the wild popula-tion as revealed by RAPD were 18.9% and 0.0960 respectively, and those of the reared stocks were rel-atively lower, with 16.7% in polymorphism and 0.0747 in mean difference. The genetic distance be-tween the two stocks was 0.0041. From the comprehensive investigation, the main reasons for the loss of genetic diversity were probably overilshing, small number of parents as broodstocks and the debatable arti-ficial ranching. Results from this study also showed that the large yellow croaker populations distributed along Fujian coastal waters including Guan-Jing-Yang still potentially wide genetic variability. It is sug-gested that genetic management and prevention should be scientifically conducted in order to maintain and improve the genetic diversity of the P. crocea population. 相似文献
12.
针对准噶尔盆地玛湖凹陷西斜坡风南地区三叠系百口泉组扇三角洲砂岩物性空间变化大、优质储集层(孔隙度大于7.4%,渗透率大于0.05×10-3μm2)预测难的问题,在沉积岩石学、地震沉积学以及地震反演和解释理论指导下,综合利用测井、岩心和三维地震等资料开展了高精度层序地层划分、沉积微相描述和优质储集层地震反演研究。建立了风南井区四级层序地层格架,明确了扇三角洲多期水进水退的充填过程,指出SSQ3和SSQ5是优质储集层的发育层系;识别出扇三角洲平原分流河道、河道间和扇三角洲前缘水下分流水道、河口坝、席状砂等沉积微相,指出扇三角洲平原是优质储集层发育相带;通过应用高分辨层序地层纵向边界和沉积相横向边界约束,进行分层相控叠后地震波阻抗反演,提升储集层预测精度,在SSQ3和SSQ5预测5个优质储集层发育区,提出3口井的井位建议,钻探均获工业油流。 相似文献
13.
In this study, the multi-resolution Kalman filter (MKF) algorithm, which can handle multi-resolution problems with high computational efficiency, was used to blend two emissivity products: the Global LAnd Surface Satellite (GLASS) (BBE) product and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) narrowband emissivity (NBE) product. The ASTER NBE product was first converted into a BBE product. A new detrending method was used to transfer the BBEs into a process suitable for the MKF. The new detrending method was superior to the two existing methods. Finally, both the de-trended GLASS and ASTER BBE products were incorporated into the MKF framework to obtain the optimal estimation at each scale. Field measurements collected in North America were used to validate the integrated BBEs. Visually, the fusion map showed good continuity, with the exception of the border areas, and the quality of the fusion map was better than that of the original maps. The validation results indicate that the MKF improved the BBE product accuracy at the coarse scale. In addition, the MKF was capable of recovering missing pixels at a finer scale. 相似文献
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15.
陆生植物氮同位素组成与气候环境变化研究进展 总被引:3,自引:0,他引:3
近年来,由于植物氮同位素组成(δ15N)记载了气候环境变化的信息,因而被广泛应用于全球变化研究中,成为古气候环境再造和了解现代气候环境变化信息的有力工具。然而,人们对气候环境引起的δ15N变化及其指示的气候环境意义并不完全清楚,这就有可能限制植物δ15N在古气候环境变化等领域研究中的应用。在概述植物氮同位素分馏和植物不同氮源的氮同位素分布的基础上,分析了温度、降水、大气CO2浓度和海拔高度等气候环境因子对陆生植物δ15N的影响以及它们的关系。指出了目前研究中存在的问题及其研究前景,认为在全球变化研究中利用植物氮同位素技术不仅可以重建古气候环境(如重建大气CO2浓度变化),揭示历史时期温度、降水的变化,而且还可以在一定的时间和空间上综合反映生态系统氮循环的特征。 相似文献
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17.
淀粉粒分析在国内外环境考古学研究中得到了大量应用,但是目前国内还没有关于淀粉粒分析、石器功能与植物利用关系的现代过程研究。本研究针对石刀这一新石器时代重要的生产和生活工具开展现代过程的模拟实验,尝试利用淀粉粒分析方法验证石刀功能及其加工的植物类型。我们利用打制的简易石片模拟石刀,对未成熟和成熟的小麦(Triticum aestivum L.)进行了共两次割穗操作,提取并观察石片割穗后不同部位表面残留物中的淀粉粒形态及其组合。实验结果表明,石片表面残留物中的淀粉粒主要来源于小麦秸秆; 小麦秸秆淀粉粒的A型和B型淀粉粒(未成熟和成熟小麦秸秆淀粉粒——A+B型淀粉粒,含量分别为90.91 % 和92.59 % )分别与其成熟籽粒的A型和B型淀粉粒形态、大小相似,具备形态鉴定的特征; 小麦秸秆中还发现了独特的多面体型淀粉粒(未成熟和成熟小麦秸秆多面体型淀粉粒含量分别为9.09 % 和7.41 % ),这是小麦种子中缺少的类型。根据本次现代实验模拟的结果,考古遗址出土石刀上提取到的淀粉粒很可能来自于植物收割(或切削)过程的残留物,结合淀粉粒分析、石刀形制和出土状况进行分析,可以获取出土石刀功能与古人类植物利用的信息。 相似文献
18.
R.G. Smith E.J. Brooker D.J. Douglas E.S.K. Quan G. Rosenblatt 《Journal of Geochemical Exploration》1984,21(1-3)
This paper discusses the application of the newly developed ELAN 250 I.C.P./mass spectrometer to exploration geochemistry. This instrument combines an inductively coupled plasma with a quadrupole mass spectrometer. The combination of these two existing technologies makes it possible for the first time to perform stable-isotope and elemental analysis rapidly and concurrently.Particular attention is paid to the use of lead isotopes to type Au and base-metal occurrences. Data are presented on galena samples obtained from the Geological Survey of Canada and the Royal Ontario Museum. Consideration is also given to the potential usefulness of Pb isotopes and trace-element data to type mineral occurrences and to identify new ones. 相似文献
19.
Anqi Wang Debin Yang Haotian Yang Maosong Mu Yikang Quan Leran Hao Wenliang Xu 《地学前缘(英文版)》2021,12(3):343-357
Mesozoic sedimentary units within the Nanzhao and Mashiping basins record the paleogeographic and tectonic evolution of the Qinling Orogen (QO). This study uses... 相似文献
20.
To investigate the solubility and the sites of incorporation of hydrogen in olivine as a function of point defect concentration, two-stage high-temperature annealing experiments have been carried out. The first annealing stage (the dry preannealing stage) was conducted at a total pressure of 0.1 MPa, a temperature of 1300° C and various oxygen fugacities in the range 10?11–10?4 MPa for times > 12 h. In these heat treatments, the samples were buffered against either orthopyroxene or magnesiowustite, or they remained unbuffered. The second annealing stage (the hydrothermal annealing stage) was performed at 300 MPa and 900–1050 ° C under a hydrogen fugacity of ~ 158 MPa for 1–5 h. Infrared spectra from the annealed samples revealed two distinct groups of bands. Group I bands occurred at wavenumbers in the range 3450–3650 cm?1, while Group II bands occurred in the range 3200–3450 cm?1. The hydrogen solubility associated with Group I bands is proportional to f O 2 to the 1/6 power for samples preannealed in contact with orthopyroxene, to the 1/3 power for samples preannealed in contact with magnesiowustite, and to the 1/13 power for samples preannealed in the absence of a solid-state buffer. The hydrogen concentration for Group II bands varies with f o 2 to the 1/3 power for opxbuffered samples, to the 1/2 power for mw-buffered samples, and to the 1/3 power for unbuffered samples. The dependence of hydrogen solubility on oxygen fugacity and orthopyroxene activity suggests that hydrogen is incorporated into the olivine structure via association with point defects. The presence of two distinct groups of absorption bands indicates that hydrogen is associated with two distinct lattice defects. The following point defect model for the mechanism of incorporation of hydrogen in olivine is consistent with these results: Hydrogen ions responsible for the Group I bands are associated with doubly charged oxygen interstitials, while hydrogen ions responsible for the Group II bands are associated with singly charged oxygen interstitials. Furthermore, the infrared bands observed in naturally derived olivines are present in spectra from our hydrothermally annealed crystals. Thus, the mechanisms of incorporation of hydrogen in olivine under geological conditions are the same as those operative under laboratory conditions. The maximum solubility reached in these experiments was ~ 360H/106Si, which corresponds to ~ 0.002 wt% of H2O. This value is a lower bound for the solubility of hydrogen in olivine under upper mantle conditions. 相似文献