A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sedim...A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard （for the trace elements）. The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% （n=12）.展开更多
Sediment cores with length of 25-45cm at 12 stations in Zhujiang(Pearl) River Estuary were sampled in summer of 1999. Chemical components (Al 2O 3, Fe 2O 3, CaO, TiO 2, Cu, Pb, Cr, Zn, Co, Ni, V, Ba, Sr and Y) and gra...Sediment cores with length of 25-45cm at 12 stations in Zhujiang(Pearl) River Estuary were sampled in summer of 1999. Chemical components (Al 2O 3, Fe 2O 3, CaO, TiO 2, Cu, Pb, Cr, Zn, Co, Ni, V, Ba, Sr and Y) and grain sizes were analyzed. Sediments in Zhujiang River Estuary are characterized by relatively coarse grain size. The grain sizes of the sediments in the area outside the estuary are relatively finer than those in the north part of the estuary but coarser than those in the middle of Lingdingyang and have a trend similar to the spatial distribution trend of some chemical components such as Fe 2O 3, Al 2O 3, TiO 2, V, Cu, Ni, Zn and Y. This showed that grain size is an important factor that controls the spatial distribution and depth profile of chemical elements in the Zhujiang River Estuary. Frequent re-suspension, re-transportation and redistribution of settled sediment on estuary floor could be deduced from the spatial distributions and depth profiles of chemical components. Except for CaO and Sr, the chemical components always enrich at the west side of, in the middle of, and at the north side of, the estuary. Fe 2O 3, Al 2O 3, Ti, V, Cr, Ni, Zn, Cu and Y in Zhujiang River Estuary sediments mainly result from rock and soil weathering except that parts of Cr, Ni, Zn Cu and Y are anthropogenic. CaO and Sr in sediments originate from marine source. Although Co as well as Pb derives from anthropogenic sources, human activities related to Co might differ from the activities related to Pb.展开更多
Malampuzha reservoir is a multipurpose reservoir in south India. Seven water samples and four sediment samples were studied for the physico-chemical and bacteriological nature of the Malampuzha reservoir water and sed...Malampuzha reservoir is a multipurpose reservoir in south India. Seven water samples and four sediment samples were studied for the physico-chemical and bacteriological nature of the Malampuzha reservoir water and sediments. Bacteriological analysis indicated the microbial contamination of the reservoir and the physico-chemical characteristics indicated that the water is non potable directly. Analysis of irrigational water quality by SAR, Kelly＇s ratio and SSP indicates that the reservoir water is suitable for irrigation. Heavy metal pollution of the sediments was evaluated based on Sediment Quality Guidelines （SQG）, Pollution Load Index （PLI） and degree of contamination （Cd） of soil in four stations. Principal Component Analysis （PCA） was done to find out the possible linear combination of the original variables of trace metals. Results of PCA showed that no collinearity existed among the studied metals. However, emphasis on the monitoring of Cu and Ni should be preferred because of its alarmingly higher contamination value.展开更多
A complete mechanism of methane pyrolysis is proposed for chemical vapor infiltration of pyrocarbon with different textures, which contains a detailed homogeneous mechanism for gas reactions and a lumped heterogeneous...A complete mechanism of methane pyrolysis is proposed for chemical vapor infiltration of pyrocarbon with different textures, which contains a detailed homogeneous mechanism for gas reactions and a lumped heterogeneous mechanism for pyrocarbon deposition. This model is easily applied to simulate gas compositions and pyrocarbon deposition in a vertical hot-wall flow reactor in the temperature range of 1,323–1,398 K without any adjusting parameters and presents better results than previous mechanisms. Results have shown that the consumption of methane and the production of hydrogen are well enhanced due to pyrocarbon deposition. Pyrocarbon deposition prevents the continuously increasing of acetylene composition and leads to the reduction in the mole fraction of benzene at long residence times in the gas phase. The carbon growth with active sites on the surface is the controlling mechanism of pyrocarbon deposition. C1 species is the precursor of pyrocarbon deposition at 1,323 K,and the primary source over the whole temperature range. As temperature increases, gas phase becomes more mature and depositions from acetylene, benzene and polyaromatic hydrocarbons become more prevalent. A general pyrocarbon formation mechanism is derived with the specific precursors and illustrates that the maturation of gas compositions is beneficial to forming planar structures with hexagonal rings or pentagon-heptagon pairs, namely, high textured pyrocarbon. The results are in well agreement with experiments.展开更多
Well Lundong-1 is located in the periclinal area on the eastern flank of the Tahe-Lunnan paleo-uplift in the Tarim Basin. A 25-m-high cave fill sequence was observed in the Upper Ordovician interval of the well at 680...Well Lundong-1 is located in the periclinal area on the eastern flank of the Tahe-Lunnan paleo-uplift in the Tarim Basin. A 25-m-high cave fill sequence was observed in the Upper Ordovician interval of the well at 6800-6825m. A third cut of cores was obtained from the top of the cave. The following conclusions were obtained by studying the cave sediments and depositional sequence, and by undertaking paleontological and elemental geochemistry analyses. 1. The cave sediments contain abundant brachiopod, gastropod, echinoderm, ostracod, and acritach fossils, which can be classified into two groups: cave autochthonous and cave allochthonous fossils (from collapse breccia dissolution or transportation by underflow). The fossils indicate that the cave was formed before the Carboniferous and partly-filled and buried during Carboniferous resubsidence. 2. Elemental geochemistry shows that the mud that filled the cave is sourced from calcareous paleo-soil and weathered crust that came from a salty environment with poor water circulation. 3. The formation and evolution of the cave occurred in three stages. The first stage occurred after the deposition of the Late Ordovician Lianglitage Formation, the second stage took place after the deposition of the Late Ordovician Sangtamu Formation, and the last stage happened after Silurian deposition. Major dissolution occurred in the latter two stages as a result of bedding-confined deep underflow karstification. Based on the reconstruction of the cave formation history, favorable paleokarst targets can be predicted and estimated to aid paleogeography and paleokarstology studies.展开更多
基金Supported by China Ministry of Science and Technology (2000DEB20081)China Ocean Mineral Resources R&D Association (COMRA) (No.DY105-05-01-05)+1 种基金China Ministry of Education(No.205089)China National Natural Science Foundation (No.40076015)
文摘A method was developed for content determination of Na, Mg, A1, Si, P,S, C1, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Ga, Nb, Zr, Y, Sr, Rb, Ba, La and Ce etc. covering 26 major, minor, and trace elements in marine sediment samples using fused glass disc by X-ray Fluorescence spectrometry. Calibration was made using marine sediment certified reference materials and the synthetic standard samples prepared by mixing several marine sediments with stream sediment and carbonate standard samples in different proportions. The matrix effect was corrected using theoretical alpha coefficients, experience coefficients and the scattered radiation as the internal standard （for the trace elements）. The accuracy of the method was evaluated by analysis of certified reference materials GBW07314, GBW07334 and GSMS6. The results are in good agreement with the certified values of the standards with RSD less than 2.60%, except for Y, Cr, Ga, Ce, La, Nb, Rb, and V with RSD less than 9.0% （n=12）.
文摘Sediment cores with length of 25-45cm at 12 stations in Zhujiang(Pearl) River Estuary were sampled in summer of 1999. Chemical components (Al 2O 3, Fe 2O 3, CaO, TiO 2, Cu, Pb, Cr, Zn, Co, Ni, V, Ba, Sr and Y) and grain sizes were analyzed. Sediments in Zhujiang River Estuary are characterized by relatively coarse grain size. The grain sizes of the sediments in the area outside the estuary are relatively finer than those in the north part of the estuary but coarser than those in the middle of Lingdingyang and have a trend similar to the spatial distribution trend of some chemical components such as Fe 2O 3, Al 2O 3, TiO 2, V, Cu, Ni, Zn and Y. This showed that grain size is an important factor that controls the spatial distribution and depth profile of chemical elements in the Zhujiang River Estuary. Frequent re-suspension, re-transportation and redistribution of settled sediment on estuary floor could be deduced from the spatial distributions and depth profiles of chemical components. Except for CaO and Sr, the chemical components always enrich at the west side of, in the middle of, and at the north side of, the estuary. Fe 2O 3, Al 2O 3, Ti, V, Cr, Ni, Zn, Cu and Y in Zhujiang River Estuary sediments mainly result from rock and soil weathering except that parts of Cr, Ni, Zn Cu and Y are anthropogenic. CaO and Sr in sediments originate from marine source. Although Co as well as Pb derives from anthropogenic sources, human activities related to Co might differ from the activities related to Pb.
文摘Malampuzha reservoir is a multipurpose reservoir in south India. Seven water samples and four sediment samples were studied for the physico-chemical and bacteriological nature of the Malampuzha reservoir water and sediments. Bacteriological analysis indicated the microbial contamination of the reservoir and the physico-chemical characteristics indicated that the water is non potable directly. Analysis of irrigational water quality by SAR, Kelly＇s ratio and SSP indicates that the reservoir water is suitable for irrigation. Heavy metal pollution of the sediments was evaluated based on Sediment Quality Guidelines （SQG）, Pollution Load Index （PLI） and degree of contamination （Cd） of soil in four stations. Principal Component Analysis （PCA） was done to find out the possible linear combination of the original variables of trace metals. Results of PCA showed that no collinearity existed among the studied metals. However, emphasis on the monitoring of Cu and Ni should be preferred because of its alarmingly higher contamination value.
基金supported by the National Natural Science Foundation of China (51521061 and 51472203)the "111" Project (B08040)the Research Fund of State Key Laboratory of Solidification Processing (NWPU),China (142-TZ-2016)
文摘A complete mechanism of methane pyrolysis is proposed for chemical vapor infiltration of pyrocarbon with different textures, which contains a detailed homogeneous mechanism for gas reactions and a lumped heterogeneous mechanism for pyrocarbon deposition. This model is easily applied to simulate gas compositions and pyrocarbon deposition in a vertical hot-wall flow reactor in the temperature range of 1,323–1,398 K without any adjusting parameters and presents better results than previous mechanisms. Results have shown that the consumption of methane and the production of hydrogen are well enhanced due to pyrocarbon deposition. Pyrocarbon deposition prevents the continuously increasing of acetylene composition and leads to the reduction in the mole fraction of benzene at long residence times in the gas phase. The carbon growth with active sites on the surface is the controlling mechanism of pyrocarbon deposition. C1 species is the precursor of pyrocarbon deposition at 1,323 K,and the primary source over the whole temperature range. As temperature increases, gas phase becomes more mature and depositions from acetylene, benzene and polyaromatic hydrocarbons become more prevalent. A general pyrocarbon formation mechanism is derived with the specific precursors and illustrates that the maturation of gas compositions is beneficial to forming planar structures with hexagonal rings or pentagon-heptagon pairs, namely, high textured pyrocarbon. The results are in well agreement with experiments.
基金supported by"Conditions for Giant Marine Carbonate Oil/Gas Fields to Form in Sichuan, Tarim Basins and the Neighboring Regions" a Key National Oil and Gas Program (Grant No. 2008ZX05004-002)
文摘Well Lundong-1 is located in the periclinal area on the eastern flank of the Tahe-Lunnan paleo-uplift in the Tarim Basin. A 25-m-high cave fill sequence was observed in the Upper Ordovician interval of the well at 6800-6825m. A third cut of cores was obtained from the top of the cave. The following conclusions were obtained by studying the cave sediments and depositional sequence, and by undertaking paleontological and elemental geochemistry analyses. 1. The cave sediments contain abundant brachiopod, gastropod, echinoderm, ostracod, and acritach fossils, which can be classified into two groups: cave autochthonous and cave allochthonous fossils (from collapse breccia dissolution or transportation by underflow). The fossils indicate that the cave was formed before the Carboniferous and partly-filled and buried during Carboniferous resubsidence. 2. Elemental geochemistry shows that the mud that filled the cave is sourced from calcareous paleo-soil and weathered crust that came from a salty environment with poor water circulation. 3. The formation and evolution of the cave occurred in three stages. The first stage occurred after the deposition of the Late Ordovician Lianglitage Formation, the second stage took place after the deposition of the Late Ordovician Sangtamu Formation, and the last stage happened after Silurian deposition. Major dissolution occurred in the latter two stages as a result of bedding-confined deep underflow karstification. Based on the reconstruction of the cave formation history, favorable paleokarst targets can be predicted and estimated to aid paleogeography and paleokarstology studies.
