Adsorption Mechanism and Kinetic Characterization of Bituminous Coal under High Temperatures and Pressures in the Linxing-Shenfu Area     

TAO Chuanqi  WANG Yanbin  LI Yong  NI Xiaoming  GAO Xiangdong 《《地质学报》英文版》2020,94(2):399-408

The majority of coalbed methane(CBM) in coal reservoirs is in adsorption states in coal matrix pores. To reveal the adsorption behavior of bituminous coal under high-temperature and high-pressure conditions and to discuss the microscopic control mechanism affecting the adsorption characteristics, isothermal adsorption experiments under hightemperature and high-pressure conditions, low-temperature liquid nitrogen adsorption-desorption experiments and CO2 adsorption experiments were performed on coal samples. Results show that the adsorption capacity of coal is comprehensively controlled by the maximum vitrinite reflectance(Ro, max), as well as temperature and pressure conditions. As the vitrinite reflectance increases, the adsorption capacity of coal increases. At low pressures, the pressure has a significant effect on the positive effect of adsorption, but the effect of temperature is relatively weak. As the pressure increases, the effect of temperature on the negative effect of adsorption gradually becomes apparent, and the influence of pressure gradually decreases. Considering pore volumes of pores with diameters of 1.7-100 nm, the peak volume of pores with diameters 10-100 nm is higher than that from pores with diameters 1.7-10 nm, especially for pores with diameters of 40-60 nm, indicating that pores with diameters of 10-100 nm are the main contributors to the pore volume. The pore specific surface area shows multiple peaks, and the peak value appears for pore diameters of 2-3 nm, indicating that this pore diameter is the main contributor to the specific surface area. For pore diameters of 0.489-1.083 nm, the pore size distribution is bimodal, with peak values at 0.56-0.62 nm and 0.82-0.88 nm. The adsorption capability of the coal reservoir depends on the development degree of the supermicroporous specific surface area, because the supermicroporous pores are the main contributors to the specific pore area. Additionally, the adsorption space increases as the adsorption equilibrium pressure increases. Under the same pressure, as the maximum vitrinite reflectance increases, the adsorption space increases. In addition, the cumulative reduction in the surface free energy increases as the maximum vitrinite reflectance increases. Furthermore, as the pressure increases, the surface free energy of each pressure point gradually decreases, indicating that as the pressure increases, it is increasingly difficult to adsorb methane molecules.  相似文献   

Isolation of CYP17 Ⅰ, 3β-HSD and AR Genes from Spotted Sea Bass (Lateolabrax maculatus) Testis and Their Responses to Hormones and Salinity Stimulations     

CHI Meili  NI Meng  JIA Yongyi  GU Zhimin  WEN Haishen 《中国海洋大学学报(英文版)》2019,(2)

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新元古代—寒武纪硫同位素异常事件(Yudomski事件)的起源与结束          下载免费PDF全文

张智礼  孟凡巍  倪培  李慧莉  卓勤功 《盐湖研究》2020,28(4):22-28

新元古代晚期—寒武纪早期是地球历史演化的关键时期,整个生物圈、大气圈和水圈在此期间都发生了巨大的变化,海水成分在其间也发生了明显的变化。而石盐流体包裹体恰恰记录了该时段海水主要离子成分的转变:海水成分从新元古代晚期的“文石海”,快速转化为寒武纪的“方解石海”；同时海水中的碳、锶、硫同位素都发生了剧烈的改变,其中海水硫酸根的硫同位素从新元古代冰期前的20‰左右,迅速升高到新元古代冰期后的35‰左右,甚至可以到45‰,海相蒸发岩沉积中的硫酸盐沉积(主要是石膏、硬石膏)则直接记录了当时海水中硫酸根的硫同位素变化。现有研究表明,新元古代晚期——寒武纪时期的海相蒸发岩沉积记录了当时海洋中存在着地质历史时期最大的硫同位素异常,即“Yudomski事件”。塔里木盆地的寒武纪早期、中期蒸发岩记录了“Yudomski事件”的硫同位素异常高值(35‰左右,甚至更高),表明这一起源于新元古代晚期的同位素异常事件持续到了寒武纪的早期和中期；塔里木盆地奥陶纪早期的蒸发岩、鄂尔多斯盆地奥陶纪中期蒸发岩和美国Williston盆地奥陶纪晚期地层的蒸发岩的硫同位素数据相似,都在+25‰左右则记录了较低的海洋硫同位素值,表明起源于新元古代冰期之后的“Yudomski事件”的硫同位素异常,持续到了寒武纪的中期,而结束于寒武纪的晚期。  相似文献   

国内盐湖卤水硼资源提取专利分析          下载免费PDF全文

李玉婷  李禾禾  倪颖  王瑜  葛飞 《盐湖研究》2020,28(3):109-114

基于中国盐湖硼资源开发动态,选择国家知识产权局专利数据,从盐湖卤水硼资源提取相关专利申请时间、地域分布、主要方法等方面进行分析。发现中国专利包含多种盐湖硼资源提取方法,并且逐步走向成熟,其中萃取法已成为研究重点。近期关于多种伴生资源综合开发的专利越来越受到关注。对国内盐湖硼资源提取技术后续开发和产业发展提出了建议。  相似文献   

大功率高频电波加热电离层的非线性物理过程          下载免费PDF全文

周晨  王翔  刘默然  倪彬彬  赵正予 《地球物理学报》2018,61(11):4323-4336

地基大功率电波加热电离层是通过地基大功率短波发射机向电离层发射无线电波，通过波-粒和波-波的相互作用将无线电波的能量注入电离层.通过这种有目的可操控的方式改变电离层电子密度和温度的分布，可以深入研究电离层中等离子体能量和物质的非线性演化过程，特别是电离层电子的非平衡态分布和加速问题.本文通过对电离层加热中几个比较重要物理过程的评述，对过去20年来我国研究学者在这一研究方向上取得的重要进展进行了介绍.  相似文献   

井下地震计的P波接收函数正演计算及其稳定性研究——以首都圈地区为例          下载免费PDF全文

郑德高  倪四道  杨卓欣  刘志 《地球物理学报》2018,61(10):3964-3979

井下地震计波形记录的P波垂向分量存在频谱极小（spectrum null）现象，导致接收函数的结果不稳定.本文以首都圈地区为例，基于平面波入射的传播矩阵理论，发展了用于计算井下地震计的接收函数正演方法.在此基础上，分析了井下地震计波形垂向分量频谱极小现象，研究其对接收函数稳定性的影响.结果表明，井下地震计波形记录垂向分量的频谱极小开始出现的频率和地震计的埋深相关.该现象可造成反卷积提取的接收函数不稳定，且不稳定情况出现在频谱极小附近的频段，可通过选择合适的高斯因子压制其对接收函数的影响.  相似文献   

加权总体最小二乘的效率优化算法     

倪福泽  王建民 《测绘通报》2020,(11):90

加权总体最小二乘法是理论上估计EIV模型参数相对严密的方法，其迭代过程中涉及的矩阵运算较为耗时，在处理大量级数据时尤其明显。PEIV模型有助于提高加权总体最小二乘法的计算效率。本文基于PEIV模型和经典最小二乘准则给出了一种加权总体最小二乘法算法，算法的推导过程简洁，易于理解，迭代过程中无需重构矩阵，减少了矩阵运算量。最后通过仿真试验验证了算法的可靠性。试验结果表明，本文算法可以取得与现有算法相同的参数估计精度且计算效率更高。  相似文献   

珠江口黄茅海底质沉积中介形类的生态类型及其分布特征          下载免费PDF全文

黄毅  吴洁  殷征欣  关瑶  倪锦锋 《海洋开发与管理》2020,37(6):89-94

文章通过对黄茅海底质沉积样品中的介形类生态类型进行研究，探讨其空间分布特征。研究结果显示：研究区内出现的介形类可划分为4种生态类型，总体表现为以近岸广盐型分子占主导地位，优势度极高；浅海多盐 真盐型分子次之；而广海真盐型和淡水 微盐型分子丰度很低。根据黄茅海河口湾的水体条件，可大致将研究区划分为5种亚环境区，各区内的介形类生态类型组成也存在较大差别，表现出不同的空间分布特征。介形类分布受海水盐度控制最大，其次为水动力条件。在水体盐度小、水动力条件强的河流入海口及其影响区域，介形类丰度小，且生态类型单一；而在黄茅海河口湾南部海域，由于海水底层盐度全年在15‰以上，水动力条件适宜，介形类丰度总体较高，生态类型增多。  相似文献   

Assessing effects of “source-sink” landscape on non-point source pollution based on cell units of a small agricultural catchment     

WANG Jin-liang  CHEN Cheng-long  NI Jiu-pai  XIE De-ti  GUO Xi  LUO Zhi-jun  ZHAO Yue 《山地科学学报》2019,(9)

Ascertaining the relationship between "source-sink" landscape and non-point source(NPS) pollution is crucial for reducing NPS pollution, however, it is not easy to realize this target on cell unit scale. To reveal the relationships between "sourcesink" landscape and NPS pollution based on cell units of a small catchment in the Three Gorges Reservoir Region(TGRR), the runoff and nutrient yields were simulated first by rainfall events on a cell unit scale based on the Annualized AGricultural Non-Point Source Pollution Model(AnnAGNPS). Landscape structure and pattern were quantified with "sourcesink" landscape indicators based on cell units including landscape area indices and locationweighted landscape indices. The results showed that:the study case of small Wangjiagou catchment highlighted a good prediction capability of runoff and nutrient export by the AnnAGNPS model. Throughout the catchment, the spatial distribution trends of four location-weighted landscape indices were similar to the trends of simulated total nitrogen(TN) and total phosphorus(TP), which highlighted the importance of spatial arrangement of "source" and "sink" landscape types in a catchment when estimating pollutant loads. Results by Pearson correlation analysis indicated that the location-weighted landscape index provided a more comprehensive account of multiple factors, and can better reflect NPS-related nutrient loss than other landscape indices applied in single-factor analysis. This study provides new findings for applying the "source-sink" landscape indices based on cell units in small catchments to explain the effect of "source-sink" landscape on nutrient export based on cell unit, and helps improve the understanding of the correlation between "source-sink" landscape and NPS pollution.  相似文献   

STUDY ON FOCAL DEPTH OF THE M_S5.4 CANGWU EARTHQUAKE IN GUANGXI          下载免费PDF全文

ZHAO Tao  CHU Ri-sheng  NI Si-dao  WANG Ying  ZHOU Yong  ZENG Xiang-fang 《地震地质》2019,41(3):619-632

On July 31th, 2016, a magnitude 5.4 earthquake struck Cangwu Country, Guangxi Zhuang Autonomous Region, it was the largest earthquake recorded by Guangxi Seismological Network since it set up. The number of people affected by the earthquake had reached 20 000, and the direct economic losses caused by the earthquake were nearly 100 million Yuan. After the earthquake, USGS provided a global earthquake catalog showing that the focal depth of Cangwu earthquake was about 24.5km. However, the result given by the Global Centroid Moment Tensor showed the focal depth of this earthquake was 15.6km. However, the result obtained by Xu Xiaofeng et al. using CAP method was 5.1km. It was clear that the focal depths of Cangwu earthquake given by different institutions were quite different from each other. However, accurate focal depth of the earthquake has important significance for exploring the tectonic mechanism near the epicenter, so it is necessary to further determine the more accurate depth of the Cangwu earthquake. In order to further accurately determine the focal depth of Cangwu earthquake, we used the global search method for travel-time residual to calculate the focal depth of this earthquake and its error range, based on the regional velocity model, which is a one-dimensional velocity model of the Xianggui tectonic belt produced by the comprehensive geophysical profile. Then, we inverted the focal mechanism of this earthquake with the CAP method. Based on this, the focal depth of Cangwu M_S5.4 earthquake was further determined by the method of the Rayleigh surface wave amplitude spectrum and the sPL phase, respectively. Computed results reveal that the focal depth of this earthquake and its error range from the travel-time residual global search method is about(13±3)km, the focal depth inverted by CAP method is about 10km, the focal depth from sPL phase is about 10km, and the focal depth from Rayleigh surface wave amplitude spectrum is about 9~10km. Finally, we confirmed that the focal depth of Cangwu M_S5.4 earthquake is about 10km, which indicates that this earthquake still occurred in the upper crust. In the case of low network density, the sPL phase and Rayleigh wave amplitude spectrum recorded by only 1 or 2 broadband stations could be used to obtain more accurate focal depth. The focal depth's accuracy of Cangwu M_S5.4 earthquake in the USGS global earthquake catalog has yet to be improved. In the future, we should consider the error of the source parameters when using the USGS global earthquake catalog for other related research.  相似文献