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991.
研究了二异氰酸酯与壳聚糖的交联反应,其产物与壳聚糖相比,酸溶解度由82.04%降到58.08%。DSC曲线表明,交联产物的热稳定性明显提高,对低价重金属离子(Hg 相似文献
992.
Qie Wenkun Ma Xueping Xu Honghe Qiao Li Liang Kun Guo Wen Song Junjun Chen Bo Lu Jianfeng 《中国科学:地球科学(英文版)》2019,62(1):112-134
The Global Boundary Stratotype Sections and Points(GSSPs) for the bases of all seven international Devonian stages have been formally defined and ratified by IUGS till 1996, and nowadays, the main tasks for Devonian stratigraphers include further subdivision of these standard stages, strictly constrained absolute ages for the boundaries, and precise neritic-pelagic and marine-terrestrial correlations using multidisciplinary stratigraphy methods. Establishment of high-resolution Devonian integrative stratigraphy framework and timescale of China would play an important role in improving regional and international correlation, facilitating the recognition of important stratigraphic levels in different paleogeographic settings, and understanding the evolution pattern of biota, paleoclimate and paleoenvironment during this critical interval. Based on well-studied bio-and chronostratigraphy of Devonian in South China and adjacent areas, in combination with recent achievements in carbon isotope stratigraphy, event stratigraphy and radioactive isotope ages, this paper briefly summarize the research history and current status of Devonian chronostratigraphy of China, and for the first time introduce Devonian integrative stratigraphy framework of China.Up to date, few studies have been conducted on the astronomical cyclostratigraphy and high-resolution radioactive isotope dating in Devonian of China, which should be our main focuses in the near future. 相似文献
993.
本文根据石油地质勘探的最新资料和元-济人工地震地壳测深剖面相应地段重新解释的结果,分析了邢台7.2级地震的构造背景和发震断裂。研究结果表明,7.2级地震震中位于束鹿断陷盆地南部次凹的东缘,该次凹发育在由新河断裂等4条缓倾铲形正断裂分制围限地台盖层而成的“斛”状构造块体上,块体之下的地壳中存在两条倾向相反的高角度断裂;地震与断陷主断裂及其控制的断陷盆地并非是简单的对应关系,7.2级地震的发震断裂不是单一的缓倾铲形新河断裂或其下方的高角度的F_3断裂和深部的东断裂,而是它们的组合,且高角度断裂是发震断裂的主要部分 相似文献
994.
We use the rotation curves of 13 galaxies to test the nonsymmetric gravitaional theory (NGT). If we follow Moffat's assumption of a constant mass-to-light for all galaxies then we shall find that the two supposedly universal constants r0, L0 to show a large scatter. By regarding the mass-to-light ratio as a free parameter for each galaxy, and adjusting the values of r0, L0, we find that NGT can well account for the observed rotation curves. Further, the mass-to-light ratios so found show the well-known trend along the Hubble morphological sequence. 相似文献
995.
全数字航测相机ADS40及其应用初探 总被引:1,自引:0,他引:1
本文简单介绍了目前国际上比较流行的线阵航空数字传感器ADS40的一些基本情况,分析了该传感器的技术优势与应用意义,并对配套应用技术的开发问题进行了初步的讨论。 相似文献
996.
Unconsolidated sand, gravel and clay deposits near Beihai and in the Leizhou Peninsula in southern China form an unconfined
aquifer, aquitard and a confined aquifer. Water and soil samples were collected from the two aquifers in the coastal Beihai
area for the determination of chemical compositions, minerals and soluble ions. Hydrogeochemical modeling of three flow paths
through the aquitard are carried out using PHREEQC to determine water–rock interactions along the flow paths. The results
indicate that the dissolution of anorthite, fluorite, halite, rhodochrosite and CO2, and precipitation of potash feldspar and kaolinite may be occurring when groundwater leaks through the aquitard from the
unconfined aquifer to the confined aquifer. Cation exchanges between Na and Ca can also happen along the flow paths. 相似文献
997.
Ping Xu 《Geotechnical and Geological Engineering》2014,32(2):337-344
Coal and gas outbursts took place about thirty times at one coal mine in China, which not only caused safety problems but also hindered the regular production in different degree. In-situ geo-stresses of two points are successfully measured near coal and gas outburst locations, and the measured maximum principal stress is approximately at the horizontal direction, while the minimum principal stress is at the vertical direction. A three-dimensional model is built with FEM software of ANSYS, the measured geo-stress are taken as boundary pressures to be applied on the FEM model, and the geo-stress fields in the coal seam are calculated. In the end, the qualitative influence of the maximum principal geo-stress on coal and gas outburst is analyzed based on the relationship between geo-stress and number of coal and gas outburst. 相似文献
998.
Xu Jiongxin 《地球表面变化过程与地形》1993,18(8):687-702
This paper describes meandering alluvial rivers with mean annual suspended-sediment concentrations of more than 100 kgm?3 on the Loess Plateau, China, and explains their formation as caused by the effect of hyperconcentrated water flow. When the river is dominated by hyperconcentrated flow, the rate of energy expenditure required for sediment transport declines significantly. Accordingly, the river channel adjusts itself to a lower channel gradient by increasing the river length, resulting in a meandering channel. Since the stable transportation of sediment by hyperconcentrated flow is dependent on river channel boundary conditions, the latter play an important role in the formation of meanders of this kind. The paper also discusses the conditions for the discrimination of meandering and braided rivers in this area. 相似文献
999.
利用宁夏及邻区的数字测震资料,选取2009年5月至2010年10月间的31个M2.7-ML4.9地震事件的波形记录,以Brune提出的震源谱为平方模型基础,通过消除观测谱中的几何扩散、非弹性衰减、场地响应、仪器响应等影响因素,得到这些地震的震源谱,根据Brune的圆盘震源模型计算并研究地震矩、矩震级、地震应力降、震源尺... 相似文献
1000.
新疆及邻区大地构造编图研究 总被引:21,自引:5,他引:21
新疆及邻区大地构造1150万的编图范围为北纬34°~50°,东经72°~98°,面积约370×10 相似文献