188 resultados para 13-126A


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植物有机体稳定碳同位素组成受植物生长期间气候环境因子的影响,包含了大量的环境信息。要真正理解植物体同位素组成所包含的环境信息首先要研究植物体同位素组成与环境之间的关系。文章通过分析2002年和2003年青藏高原东部青海省门源县境内隶属于19科41属51种植物叶片的δ~(13)C值,研究高寒草甸植物稳定碳同位素组成的年间变化及其与环境因子的关系,分析影响δ~(13)C值变化的关键因子。结果表明,所测植物的δ~(13)C值分布在一个很小的范围-29.2‰~-24.9‰之间,平均值为-26.9‰,说明所测植物的光合作用均通过C3途径实现,这可能与该研究区较低温度有关。研究发现一年生植物δ~(13)C值明显低于多年生植物,而且一年生和多年生植物δ~(13)C值之间的差异在2002年(t=-3.031,P〈0.01)和2003年(t=-3.567,P〈0.001)均能达到显著性水平,表明多年生植物水分利用效率显著高于一年生植物,能更好的适应该地区寒冷干燥的低温环境。两年间植物δ~(13)C值有明显不同,2003年显著低于2002年(t=6.786,P〈0.001)。通过分析两年间环境因子的变化认为植物叶片δ~(13)C值的年间变化主要是由于降水的变化引起的,随降雨量的增加而降低。不同植物种δ~(13)C值年间变化差别很大,反应了植物对环境变化的不同响应。在植被恢复中应选用植物δ~(13)C值随环境变化存在较大差异的物种,因为此类物种能够采取不同的对策适应该地区环境的变化。

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总结了作者所测定过的多取代酮及其糖甙类衍生物的1H和13CNMR位移数据.着重就取代基与结构的关系进行了探讨.认为多取代酮1位和8位取代情况直接影响着其他位置的化学位移数值.这一现象可以直接用于该类化合物的结构鉴定.

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Open-top chambers were used to estimate the possible effects of global warming on delta C-13 of seven plant species grown in alpine meadow ecosystem. The delta C-13 values of plant species were lower after long-term growth in open-top chambers. In the course of experiment, temperature significantly increased inside the chambers by 4 degrees C. Plant species grown at a lower elevation above sea level had higher delta C-13 values as compared to those grown at a higher elevation. This was in accordance with the effect of open-top chamber on delta C-13 values in plants. Greater availability of CO2 and lower water vapor as indicated by an increase in discrimination against (CO2)-C-13, probably result in more negative delta C-13 values of plants because higher stomatal conductance increases availability of CO2 and causes greater discrimination against (CO2)-C-13. The plant species studied could be the indicator species for testing global warming by the change in carbon isotope ratios at the two growth temperatures.

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Junggar Basin has a large amount of recoverable reserves, However, due to the unfavorable factors, such as bad seismic data quality, complex structure with many faults and less wells, the exploration of oil and gas is still relatively limited, so advanced theoretical guidance and effective technical supports are desirable. Based on the theories of sedimentology, as well as comprehensive studies of outcrops, seismic data, drilling data and setting of this area, the paper establishes the isochronous correlation framework, and analyzes the sedimentary facies types and provenance direction, and obtains the profile and plain maps of the sedimentary facies combined with the logging constrained inversion. Then the paper analyzes the reservoir controlling factors, reservoir lithology attribute, 4-property relationship and sensibility based on the sedimentary facies research, and sets up a 3D geological model using facies controlled modeling. Finally, the paper optimizes some target areas with the conclusions of reservoir, structure and reservoir formation.Firstly, the paper establishs the isochronous correlation framework by the seismic data, drilling data and setting of this area. The sedimentary facies in Tai13 well block are braided river and meandering river according to the analysis of the lithology attribute, logging facies and sedimentary structure attribute of outcrop. The concept of “wetland” is put forward for the first time. The provenance direction of Badaowan and Qigu formation is obtained by the geology setting, sedimentary setting and paleocurrent direction. The paper obtains the profile and plain maps of the sedimentary facies from the sand value of the wells and the sand thickness maps from the logging constrained inversion. Then, this paper takes characteristics and control factors of the Jurassic reservoirs analysis on thin section observation, scanning transmission electron microscope observation and find out the petrology characteristics of reservoir, space types of reservoir and lithofacies division. In this area, primary pores dominate in the reservoir pores, which believed that sedimentation played the most important roles of the reservoir quality and diagenesis is the minor factor influencing secondary porosity. Using stochastic modeling technique,the paper builds quantitative 3-D reservoir Parameter. Finally, combined the study of structure and reservoir formation, the reservoir distribution regularity is concluded: (a) structures control the reservoir formation and accumulation. (b) Locating in the favorable sedimentary facies belt. And the area which meets these conditions mentioned above is a good destination for exploration.

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The loess-paleosols in the Chinese loess plateau and Europe are the main eolian sediment sequences in mid-latitude area of north hemisphere. They record not only the paleoclimatic and paleoenvironmental processes since the last interglacial, but also the configuration of magnetic field during polarity transition. Comparisons of environmental magnetism, paleomagnetism and climate proxy analysis has been made for the loess/paleosol sequences in Datong and Czech Republic. The Datong loess/paleosol sequence is composed of the Holocene soil SO, the last glacial loess LI, the last interglacial soil SI and the upper penultimate loess L2. A basalt layer occurs in L2. The main magnetic minerals in LI and SI are magnetite, maghemite and ilmenite. The presence of local volcanic elastics in the loess and the characteristics of the magnetic minerals indicate that there are local materials in Datong loess, which differentiate the Datong loess from the central and eastern loess of the Chinese Loess Plateau. In addition, there are four polarity events in Datong loess, which are generally consistent with Gothenburg> Mono Lake, Laschamp and Blake events. Some signals of the East Asia monsoon were recorded in the Datong loess/paleosol sequences. Magnetic susceptibility, the content of >63um grains and the organic matter are used as climate proxies, which are similar to those of the typical eolian sediments in the loess plateau. In addition, it is possible that the Datong loess also recorded the Younger Dryas and the climatic fluctuations during the Holocene. The main magnetic minerals in the loess/paleosol at Znojmo section are magnetite, maghemite, hematite, pyrite, pyrrhotite and goethite. The morphology of these grains reveals that the iron sulfides originated from the eluvium loam above hypothetical ore deposits in the vicinity of the section or glaciofluvial sediments from nearby glacial margins. The pattern of the susceptibility variation at Dolni Vestonice section is coincident with that of the organic matter content. The grain size variation along the section recorded the climate instability since the last interglacial. The climate events in the Dolni Vestonice section may be correlated with the Heinrich events recorded in North Atlantic sediments, suggesting they controlled by the same marine-continent climate system.

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为了研究植物营养元素的含量和δ~(13)C值随海拔而变化的相关关系,沿着海拔450 m的贵州茂兰至海拔1330 m的贵州安顺一线,采集和分析研究了C_3植物——小果蔷薇(R.cymosa Tratt)的叶片。分析结果表明,植物叶片中营养元素含量随着海拔的上升而产生的变化是:氮、磷和钾的含量会在增高,而钙和镁的含量却会降低。植物叶片的δ~(13)C值会增大,其变幅为+2.4‰/1000m。

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对13万年以来洛川黄土-古土壤序列中固定铵态氮进行了分析。末次间冰期S1占土壤中固定铵态氮含量最高,其次为冰后期S0古土壤,末次冰期形成的马兰黄土最低;而且,固定铵态氮的分布在马兰黄土中也能体现出三次小的低-高值的波动特征。洛川黄土13万年以来固定铵态氮的分布与磁化率和<2μm组分的分布相似。在此基础上,利用马兰黄土中粒度与固定铵态氮的相关关系,计算了S1古土壤中固定铵的分布,并与实测结果进行了对比,推测S1古土壤中固定铵态氮有轻微的损失,尽管如此,S1古土壤中固定铵态氮含量仍然高于黄土。鉴于黄土-古土壤序列中固定铵态氮的分布与粉尘粒度有密切的关系,能与气候变化较好地对应,它可视为反映黄土高原区东亚冬季风强,弱周期性变化较好的替代性指标。

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对末次间冰期以来洛川黄土进行了有机磷/无机磷(Porg/Pinorg)比值测量。结果表明,黄土中Porg/Pinorg比值的分布主要受降水量和温度的影响,是有机磷和无机磷在不同时期随气候变化相互转化的结果。此指标的变化与黄土—古土壤的变化大致相关,与洛川黄土磁化率曲线相一致,与深海氧同位素可进行很好的对比。此比值与夏季风强弱程度乃至与全球气候变化有密切的联系。Porg/Pinorg比值可作为一种反映古气候环境变迁的新指标。