A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas ch...A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and pervasion, and that a part of the migrated methane that remained unoxidized could emit into the atmosphere. Methane emission rates varied less in the oil/gas field because the whole region was homogeneous in geology and geography, with a standard deviation of less than 0.02 mg/(m2·h). These were the differences in methane emission flux in the day and at night in the oil/gas field. The maximum methane emission flux reached 0.15 mg/(m2·h) at 5:00-6:00 early in the morning, and then decreased gradually. The minimum was shown 0.10 mg/(m2·h) at 17:00-18:00 in the afternoon, and then increased gradually. The daily methane released flux of the study area was 2.89 mg/(m2·d), with a standard deviation of 0.43 mg/(m2·d), using the average methane flux of every hour in a day for all chambers. δ13C of methane increased with the increase of methane concentration in the flux chambers, further indicating that the pyrogenetic origin of methane was come from deep oil/gas reservoirs.展开更多
The removal of Cd, Cu, Ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The re...The removal of Cd, Cu, Ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The results showed that to add geological materials in combination with sodium carbonate injection would notably enhance the efficiency of heavy metal removal to varying degrees. Pure limestone was found the best one among the four materials mentioned above for removing heavy metals from mine water. The removal efficiencies of pure limestone when it is ground as fine as 30–60 meshes are 58.6% for Cd, 100% for Cu, 47.8% for Ni, and 36.8% for Zn at 20℃. The optimum pH is about 8.9 to 9.1. The mechanism of higher effective removal, perhaps, is primarily due to co-precipitation under the control of calcite-related pH value. According to this research, Na2CO3 injection manners, including slug dosing and drip-wise, seemed to have little impact on the efficiency of heavy metal removal.展开更多
目的运用系统评价的方法探讨血浆红细胞分布宽度(RDW)与心房颤动导管消融术后复发之间的相关性。方法计算机检索相关数据库(PubMed、EMbase、Web of Science、Ovid、万方、维普、中国知网、中国生物医学文献数据库),检索关于RDW与心房...目的运用系统评价的方法探讨血浆红细胞分布宽度(RDW)与心房颤动导管消融术后复发之间的相关性。方法计算机检索相关数据库(PubMed、EMbase、Web of Science、Ovid、万方、维普、中国知网、中国生物医学文献数据库),检索关于RDW与心房颤动导管消融术后复发相关研究,搜集符合要求的病例对照或队列研究,提取效应指标和相关研究临床资料,采用Stata 12.0软件进行Meta分析。结果共纳入6篇研究文献,包括1387例心房颤动导管消融术后患者。Meta分析结果显示:与导管消融术后心房颤动未复发组相比,心房颤动复发组红细胞分布宽度水平显著升高(SMD=0.66,95%CI:0.33~1.00,P<0.05),两组差异有统计学意义。结论RDW水平升高与心房颤动导管消融术后复发有关,RDW可作为导管消融术后房颤复发的预测因子。展开更多
基金the National Natural Sci-ence Foundation of China (No. 40273034)the Science Foundation of Hangzhou Dianzi University
文摘A static flux chamber method was applied to study natural emissions of methane into the atmosphere in the Yakela condensed oil/gas field in Talimu Basin, Xinjiang, China. Using an online method, which couples a gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/C/MS) together, the 13C/12C ratios of methane in the flux chambers were measured. The results demonstrated that methane gases were liable to migrate from deep oil/gas reservoir to the surface through microseepage and pervasion, and that a part of the migrated methane that remained unoxidized could emit into the atmosphere. Methane emission rates varied less in the oil/gas field because the whole region was homogeneous in geology and geography, with a standard deviation of less than 0.02 mg/(m2·h). These were the differences in methane emission flux in the day and at night in the oil/gas field. The maximum methane emission flux reached 0.15 mg/(m2·h) at 5:00-6:00 early in the morning, and then decreased gradually. The minimum was shown 0.10 mg/(m2·h) at 17:00-18:00 in the afternoon, and then increased gradually. The daily methane released flux of the study area was 2.89 mg/(m2·d), with a standard deviation of 0.43 mg/(m2·d), using the average methane flux of every hour in a day for all chambers. δ13C of methane increased with the increase of methane concentration in the flux chambers, further indicating that the pyrogenetic origin of methane was come from deep oil/gas reservoirs.
基金granted by the Science Foundation of China Postdoctors (No. 20070420214)the Natural Science Foundation of Shaanxi Province (No. SJ08D03)
文摘The removal of Cd, Cu, Ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The results showed that to add geological materials in combination with sodium carbonate injection would notably enhance the efficiency of heavy metal removal to varying degrees. Pure limestone was found the best one among the four materials mentioned above for removing heavy metals from mine water. The removal efficiencies of pure limestone when it is ground as fine as 30–60 meshes are 58.6% for Cd, 100% for Cu, 47.8% for Ni, and 36.8% for Zn at 20℃. The optimum pH is about 8.9 to 9.1. The mechanism of higher effective removal, perhaps, is primarily due to co-precipitation under the control of calcite-related pH value. According to this research, Na2CO3 injection manners, including slug dosing and drip-wise, seemed to have little impact on the efficiency of heavy metal removal.
文摘目的运用系统评价的方法探讨血浆红细胞分布宽度(RDW)与心房颤动导管消融术后复发之间的相关性。方法计算机检索相关数据库(PubMed、EMbase、Web of Science、Ovid、万方、维普、中国知网、中国生物医学文献数据库),检索关于RDW与心房颤动导管消融术后复发相关研究,搜集符合要求的病例对照或队列研究,提取效应指标和相关研究临床资料,采用Stata 12.0软件进行Meta分析。结果共纳入6篇研究文献,包括1387例心房颤动导管消融术后患者。Meta分析结果显示:与导管消融术后心房颤动未复发组相比,心房颤动复发组红细胞分布宽度水平显著升高(SMD=0.66,95%CI:0.33~1.00,P<0.05),两组差异有统计学意义。结论RDW水平升高与心房颤动导管消融术后复发有关,RDW可作为导管消融术后房颤复发的预测因子。
