检索结果-南通市图书馆

江西龙南花岗岩风化壳形成和演化的铀系不平衡约束

在线全文

学校读者我要写书评

暂无评论

地学前缘 2024年第4期31卷 366-379页

作者：贾国栋徐胜刘丛强天津师范大学京津冀生态文明发展研究院天津300387 天津大学地球系统科学学院天津300072

花岗岩风化壳在我国华南地区广泛分布,其形成和演化对地貌、生态环境和矿产资源等具有重要影响。作为风化壳最基本的参数之一,生成速率是理解风化壳形成和演化的关键因子。铀系不平衡法是当前广泛应用于确定风化壳生成速率的重要地球化... 详细信息

花岗岩风化壳在我国华南地区广泛分布,其形成和演化对地貌、生态环境和矿产资源等具有重要影响。作为风化壳最基本的参数之一,生成速率是理解风化壳形成和演化的关键因子。铀系不平衡法是当前广泛应用于确定风化壳生成速率的重要地球化学手段,由于稀释剂获取困难,我国开展的研究较少。本研究以江西龙南花岗岩风化壳剖面为研究对象,开展铀系不平衡研究以确定其生成速率。研究结果显示:风化壳剖面中U和Th的含量范围分别为(3.25~3.39)×10^(-6)和(41.46~47.67)×10^(-6);活度比(^(234)U/238U)a、(^(230)Th/^(234)U)a和(^(230)Th/^(232)Th)a范围分别为1.008~1.023、1.063~1.112和0.239~0.271。通过铀系不平衡法对铀系同位素进行拟合后得到风化壳20~120 cm区域的演化时间约为841 ka,据此确定风化壳的生成速率约为1.2 m/Ma。本研究中,控制风化壳生成速率的因素主要是表层覆盖,气候和构造的影响很小。此外,由于风化壳的生成速率远低于宇宙成因核素确定的剥蚀速率,因此风化壳的演化状态为厚度逐渐减小的非稳态。

关键词：铀系不平衡法生成速率花岗岩风化壳演化状态非稳态

Interfacial processes and mechanisms of synergistic degradation of dichlorobiphenyl by white rot fungi and magnetite nanoparticles

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2023年第9期66卷 2057-2065页

作者： Le CHANG Guanghui YU congqiang liu Institute of Surface-Earth System Science School of Earth System ScienceTianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai RimBohai Coastal Critical Zone National Observation and Research StationTianjin UniversityTianjin 300072China

The rapid increase in the artificial syntheses of organic pollutants has raised widespread ***,the mechanisms by which fungi degrade these new organic pollutants in the environment and adapt to environmental stressors remain *** this study,Phanerochaete chrysosporium,a model white rot fungus,was used to explore the interfacial processes and mechanisms for synergistic degradation of 4,4′-dichlorobiphenyl(PCB15)with magnetite *** results showed that after 3 and 5 days of cultivation with Phanerochaete chrysosporium alone,the rates for PCB15 degradation were 32%and 65%,respectively,indicating that the white rot fungus itself was able to degrade the organic ***,the addition of magnetite nanoparticles significantly enhanced the degradation of PCB15 by Phanerochaete *** cocultivation for 3 and 5 days,the rates for PCB15 degradation increased to 42%and 84%,*** radiation-based Fourier transform infrared spectromicroscopy(SR-FTIR)showed that the magnetite particles were tightly adhered to the fungal hyphae and were unevenly distributed on the hyphal ***,cocultivation of the fungus and magnetite nanoparticles significantly enhanced the nanozymatic activity of magnetite.A linear regression model provided a significantly negative correlation(r=−0.96,p<0.001)between the nanozymatic activity of the magnetite and the concentration ratio of the PCB15,supporting the hypothesis that white rot fungi degraded the PCB15 by enhancing the nanozyme activity of ***-resolution X-ray photoelectron spectroscopy(XPS)revealed that the nanozymatic activity of magnetite was mainly governed by oxygen vacancies on the mineral surfaces rather than the iron ***,these findings increase our understanding of the powerful capabilities of fungi in terms of stress resistance and adaptation to extreme environments and provide new insights into fungal-mediated degradation of organic po

关键词： Magnetite nanoparticles Nanozymes Oxygen vacancies White rot fungi X-ray photoelectron spectroscopy Synchrotron radiation based FTIR spectromicroscopy Dichlorobiphenyl

Discrimination between extraneous nitrogen input and interior nitrogen release in lakes

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2004年第9期47卷 813-821页

作者： XIAO Huayun liu congqiang The Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China The Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

In this study the authors determined the nitrogen isotopes of nitrate and the carbon and nitrogen contents of water samples from the Hongfeng Lake and inflowing streams, and, on this basis, discriminated the extraneous nitrogen input and the interior nitrogen release (organic matter decomposition) in the lake. The results showed that the amount of extraneous nitrogen input into the Hongfeng Lake increases and the interior nitrogen release from the lake is intensified in winter and spring. Nitrogen mixing is relatively obvious at the catchments between the lake inlet and inflowing streams, while organic matter decomposition (nitrification) is most intense in the middle and lower reaches of the lake. In winter and spring the organic matter decomposition takes place mainly at the middle level of the water column in the middle and lower reaches of the lake, which has a bearing on the abundance of degraded organic matter at this water level. This part of degraded organic matter contains a considerable proportion of hydrogenous nitrogen in the lake.

关键词： extraneous nitrogen input, interior nitrogen release, Hongfeng Lake.

Response of biomass accumulation and nodulation by Vicia villosa to soil conditions:Evidence from δ^(13) C and δ^(15) N isotopes

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2012年第2期31卷 111-119页

作者： Piao Hechun liu congqiang The State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

Vicia villosa is an annual legume plant,and is mainly used for green manure by farmers in southwest *** growth experiments were performed on six *** concentrations of mineral nutrients and soluble sugar,and the changes of carbon and nitrogen isotopic composition within and among organs of Vicia were deter- *** differences in legume growth were found in response to soil type and its moisture *** Vicia villosa was relatively well adapted to growth in limestone soils than sandstone *** distribution of sugar concentrations andδ1 3C-differences between roots and leaves indicate that the translocation of sugars from leaves to roots may be restricted by soil ***,there was an inhibition of Pi distribution from roots to leaves, resulting in over optimum threshold of N/P *** may originate from the feedback regulation in the legume, where soluble sugar could not be distributed from leaves to *** results ofδ1 5N values in tissues suggest that there should be different preferential use of nitrogen resource by legume during the formation of nodules:before nodule formation the legume preferentially utilizes inorganic nitrogen from soils,but afterwards the nitrogen should be mainly from *** results indicate that the lack of nodulation development,except for S2,should be ascribed to the factor controlling bi-direction nutrient transfer,which should be efficiency of establishment symbiosis with arbuscular mycorrhiza before nodulation *** is predicted that the species of Vicia villosa should be a legume associated with dual symbiosis with rhizobia and mycorrhiza.

关键词：同位素组成土壤条件根瘤形成毛苕子生物量豆科植物可溶性糖反应

Situation of sewage input reflected by nitrogen isotopic composition in a sediment core of Hongfeng Lake

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2006年第8期51卷 971-976页

作者： XIAO Huayun liu congqiang State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

Nitrogen in Hongfeng South Lake water mainly comes from sewage with high N concentra- tions from Pingba Chemical Fertilizer Plant (PCFP). Studies on the sediment core HF010427 sampled in the lake showed that the upward increase of nitrogen isotopic composition of sedimentary organic nitrogen (δ 15Norg) accorded with the trend of industrial total production (TP) of PCFC. On the contrary, diagenesis will theoretically cause an upward decrease of δ 15Norg. Because no treatment of sewage water was carried out, TP corresponds with sewage emission, indicat- ing that sedimentary δ 15Norg can reflect well the total trend of sewage input. The very similar profile shape between nitrogen isotopic composition of sedimen- tary absorbed ammonium (δ 15NH4+absorbed) and TP of PCFP suggests that δ 15NH4+absorbed can be used to reconstruct more detailed situation of sewage input. The study has a reference to history investigation of sewage input.

关键词：沉积核心污水处理氮同位素湖泊

Stable carbon isotopic composition of soil organic matter in the karst areas of Southwest China

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2008年第2期27卷 171-177页

作者： ZHU Shufa liu congqiang College of Chemical Engineering Henan University of Science and Technology Luoyang 471003 China State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

This study dealt with the distribution characteristics of soil organic carbon (SOC) and the variation of stable carbon isotopic composition (δ13C values) with depth in six soil profiles, including two soil types and three vegetation forms in the karst areas of Southwest China. The δ13C values of plant-dominant species, leaf litter and soils were measured using the sealed-tube high-temperature combustion method. Soil organic carbon contents of the limestone soil profiles are all above 11.4 g/kg, with the highest value of 71.1 g/kg in the surface soil. However, the contents vary between 2.9 g/kg and 46.0 g/kg in three yellow soil profiles. The difference between the maximum and minimum δ13C values of soil organic matter (SOM) changes from 2.2‰ to 2.9‰ for the three yellow soil profiles. But it changes from 0.8‰ to 1.6‰ for the limestone soil profiles. The contrast research indicated that there existed significant difference in vertical patterns of organic carbon and δ13C values of SOM between yellow soil and limestone soil. This difference may reflect site-specific factors, such as soil type, vegetation form, soil pH value, and clay content, etc., which control the contents of different organic components comprising SOM and soil carbon turnover rates in the profiles. The vertical variation patterns of stable carbon isotope in SOM have a distinct regional character in the karst areas.

关键词：碳元素同位素有机物质喀斯特地貌

Simulation of surface runoff in theWujiang River watershed based on GIS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2007年第3期26卷 284-289页

作者： TANG Congguo liu congqiang State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academic of Sciences Guiyang 550002 China Graduate University Chinese Academic of Sciences Beijing 100049 China

Surface runoff in the Wujiang River watershed was simulated by a GIS-based method using precipitation, hydrology data, and land-use data. The volume of surface runoff is chiefly controlled by climates, topographical characteristics and types of land use at the watershed. Five subwatersheds that can represent the whole watershed were chosen and their average annual precipitation, average annual surface runoff and current land use were calculated respectively in the grid model of the Wujiang River watershed based on the climate and hydrology data from 1965 to 2000 and the land-use data acquired in the year of 2000. Surface runoff is assumed to be a function of precipitation and land use and the multiple regression tool is used to determine the relationship between surface runoff, precipitation and present land use. Thus, the rainfall-runoff model for each land-use type has been established. When calibrating these models, the results show that the percent errors are all below 7%, which indicates that the accuracy of this simulation is high.

关键词：分水岭表面径流底流乌江

Differences in uptake and distribution patterns between zinc and cadmium in Vicia villosa

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2010年第4期29卷 416-421页

作者： PIAO Hechun liu congqiang The State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

Vicia villosa is an annual legume ***-growing experiments were performed on six plots under different soil *** in the concentrations of Zn and Cd in tissues were *** in distribution patterns between Zn and Cd appeared during growing:the concentrations of Zn in roots in sandstone-derived soils were relatively higher than those in limestone-derived soils,and the uptake patterns of Zn by roots should be similar to those of iron(Fe).However,the concentrations of Cd in roots in limestone-derived soils were higher than those in sandstone-derived soils,and the uptake patterns of Cd by roots should be similar to those of manganese(Mn).On the contrast,the distribution patterns of Zn were similar to those of Mn,while the distribution patterns of Cd were similar to those of Fe in tissues,indicating that the uptake patterns of Zn and Cd were different from distribution patterns.

关键词：锌吸收毛苕子分布模式镉土壤条件分布格局根系形态豆科植物

Noble gas abundances and isotopic compositions in mantle-derived xenoliths,NE China

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第9期47卷 755-760页

作者： Sheng Xu congqiang liu Acad Sinica Inst Geochem Guiyang 550002 Peoples R China

Following the researches of helium isotopic compositions in mantle-derived xenoliths in eastern China, this study reported noble gas abundances and isotopic compositions of mantle-derived xenoliths from Kuandian of Liaoning Province, Huinan of Jilin Province and Hannuoba of Hebei Province. Compared with the middle ocean ridge basalt (MORB) and other continental areas, mantle-derived xenoliths in NE China are characterized by slightly low noble gas abundances, 3He/4He equivalent to or lower than that of MORB, 40Ar/36Ar lower than that of MORB, 38Ar/36Ar and Ne-Kr-Xe isotopic ratios equivalent to those of atmosphere. These results indicate the heterogeneity of subcontinental lithospheric mantle beneath northeastern China, that is, a MORB reservoir-like mantle beneath Kuandian and an enriched/metasomatized mantle beneath Huinan. Low 40Ar/ 36Ar ratios in the three studied areas may imply that a subducted atmospheric component has been preserved in the subcontinental lithospheric mantle.

关键词： mantle-derived xenolith noble gas abundance isotopic composition enriched mantle NE China.