Early carbonate cements in the Yanchang Formation sandstones are composed mainly of calcite with relatively heavier carbon isotope(their δ18O values range from-0.3‰--0.1‰) and lighter oxygen isotope(their δ18O val...Early carbonate cements in the Yanchang Formation sandstones are composed mainly of calcite with relatively heavier carbon isotope(their δ18O values range from-0.3‰--0.1‰) and lighter oxygen isotope(their δ18O values range from-22.1‰--19.5‰).Generally,they are closely related to the direct precipitation of oversaturated calcium carbonate from alkaline lake water.This kind of cementation plays an important role in enhancing the anti-compaction ability of sandstones,preserving intragranular volume and providing the mass basis for later disso-lution caused by acidic fluid flow to produce secondary porosity.Ferriferous calcites are characterized by relatively light carbon isotope with δ13C values ranging from-8.02‰ to-3.23‰,and lighter oxygen isotope with δ18O values ranging from-22.9‰ to-19.7‰,which is obviously related to the decarboxylation of organic matter during the late period of early diagenesis to the early period of late diagenesis.As the mid-late diagenetic products,ferriferous calcites in the study area are considered as the characteristic authigenic minerals for indicating large-scaled hydrocarbon influx and migration within the clastic reservoir.The late ankerite is relatively heavy in carbon isotope with δ13C values ranging from-1.92‰ to-0.84‰,and shows a wide range of variations in oxygen isotopic composition,with δ18O values ranging from-20.5‰ to-12.6‰.They are believed to have nothing to do with decarboxylation,but the previously formed marine carbonate rock fragments may serve as the chief carbon source for their precipitation,and the alkaline diagenetic environment at the mid-late stage would promote this process.展开更多
Light hydrocarbon (methane, ethane, propane, butane and CO2) test and C isotopic analysis of CO are conducted for over 100 lower-layer atmospheric samples from the East China Sea slope and the Okinawa Trough. The resu...Light hydrocarbon (methane, ethane, propane, butane and CO2) test and C isotopic analysis of CO are conducted for over 100 lower-layer atmospheric samples from the East China Sea slope and the Okinawa Trough. The results show that the lower-layer atmosphere mainly consists of CO2 and then of CH4, and the CO2 concentrations are calculated to have a high average value of 0.87 omega/10(-2) about three times that of the regional background (0-3 omega/10(-2)). The result also shows that the average value of C isotope - 20.8 x 10(-3) is given to the CO2, inferring that it is inorganic gas. Thus, for the future 's work in the Okinawa Trough, special attention should be paid to CO2 hydrate, which is very possibly an important hydrate type.展开更多
为了阐明裸子植物中纤维素与木素之间的连接方式,从多糖的角度分析糖单元与木素苯丙烷结构单元之间的共价键连接方式,合成了带6-13 C标记的纤维素前驱物尿苷二磷酸葡萄糖,并将其与PAL酶的抑制剂AOPP及外源性木素前驱物松柏醇-β-D-葡萄...为了阐明裸子植物中纤维素与木素之间的连接方式,从多糖的角度分析糖单元与木素苯丙烷结构单元之间的共价键连接方式,合成了带6-13 C标记的纤维素前驱物尿苷二磷酸葡萄糖,并将其与PAL酶的抑制剂AOPP及外源性木素前驱物松柏醇-β-D-葡萄糖苷一起投入生长中的银杏植物体内。碳13丰度检测得知纤维素在细胞壁的沉积主要是从在初生壁开始,高分辨率固体核磁13 C NMR分析证实了纤维素6位碳与木素以苯甲醚键等方式连接。展开更多
文摘Early carbonate cements in the Yanchang Formation sandstones are composed mainly of calcite with relatively heavier carbon isotope(their δ18O values range from-0.3‰--0.1‰) and lighter oxygen isotope(their δ18O values range from-22.1‰--19.5‰).Generally,they are closely related to the direct precipitation of oversaturated calcium carbonate from alkaline lake water.This kind of cementation plays an important role in enhancing the anti-compaction ability of sandstones,preserving intragranular volume and providing the mass basis for later disso-lution caused by acidic fluid flow to produce secondary porosity.Ferriferous calcites are characterized by relatively light carbon isotope with δ13C values ranging from-8.02‰ to-3.23‰,and lighter oxygen isotope with δ18O values ranging from-22.9‰ to-19.7‰,which is obviously related to the decarboxylation of organic matter during the late period of early diagenesis to the early period of late diagenesis.As the mid-late diagenetic products,ferriferous calcites in the study area are considered as the characteristic authigenic minerals for indicating large-scaled hydrocarbon influx and migration within the clastic reservoir.The late ankerite is relatively heavy in carbon isotope with δ13C values ranging from-1.92‰ to-0.84‰,and shows a wide range of variations in oxygen isotopic composition,with δ18O values ranging from-20.5‰ to-12.6‰.They are believed to have nothing to do with decarboxylation,but the previously formed marine carbonate rock fragments may serve as the chief carbon source for their precipitation,and the alkaline diagenetic environment at the mid-late stage would promote this process.
文摘Light hydrocarbon (methane, ethane, propane, butane and CO2) test and C isotopic analysis of CO are conducted for over 100 lower-layer atmospheric samples from the East China Sea slope and the Okinawa Trough. The results show that the lower-layer atmosphere mainly consists of CO2 and then of CH4, and the CO2 concentrations are calculated to have a high average value of 0.87 omega/10(-2) about three times that of the regional background (0-3 omega/10(-2)). The result also shows that the average value of C isotope - 20.8 x 10(-3) is given to the CO2, inferring that it is inorganic gas. Thus, for the future 's work in the Okinawa Trough, special attention should be paid to CO2 hydrate, which is very possibly an important hydrate type.
文摘为了阐明裸子植物中纤维素与木素之间的连接方式,从多糖的角度分析糖单元与木素苯丙烷结构单元之间的共价键连接方式,合成了带6-13 C标记的纤维素前驱物尿苷二磷酸葡萄糖,并将其与PAL酶的抑制剂AOPP及外源性木素前驱物松柏醇-β-D-葡萄糖苷一起投入生长中的银杏植物体内。碳13丰度检测得知纤维素在细胞壁的沉积主要是从在初生壁开始,高分辨率固体核磁13 C NMR分析证实了纤维素6位碳与木素以苯甲醚键等方式连接。
