19 resultados para on-road studies


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In the complex structure areas, velocity field building and structure mapping are important for seismic exploration. With the development of seismic exploration, the methods of structure mapping, reservoir prediction and reservoir description all require high precious velocity field. And more accurate depth-structure maps are required for well site design. Aiming at the problems and defects in velocity analysis and structure mapping in oil seismic exploration, the paper which is based on the studies of real data in several areas combines the theories with practical application, and analyzes the precision and applicability of several methods of velocity model building. After that, the following methods are mainly studied: the coherence inversion methods based on the pre-stack CMP gathers or stacking velocity; the interval velocity inversion methods constrained by multi-well; the Random Simulation method; 3D Image Ray Map Migration method and the structure mapping in floating datum and in fixed datum, and then we conclude the method of building high precious seismic velocity field and structure mapping with variable velocity. Firstly, the paper analyses the distributing rule of the velocity variation in the areas with complex structures in the northwest of China, then points out that velocity is a crucial factor which influences the precision of structure mapping, and the velocity variations have something to do with the shapes of the structures, the variety of lithology and so on. The key point of improving the precision of seismic velocity field is to obtain a structure mapping with high precision. We also describe the range and conditions of these methods. Secondly, by comparing many popular methods of velocity model building, we propose a new method in the use of velocity model building. The new method is more effective in velocity model building under every kind of complex condition and is worthy of spreading. At last, the paper fingers out that it is a system engineering to study variable velocity mapping in every kind of complex structure areas. Every step of the work can affect the final results. So it is important to build high efficient and practical velocity model and the flows of mapping processing. The paper builds the flows and gives some examples. The method has been applied in more than ten exploring surveys. The application proves that this method could bring good effect on researching on low-amplitude trap, reservoir prediction, reservoir description and the integrated research of oil&gas geology. Keywords: structure mapping velocity model building complex structure variable velocity media

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Based on previous studies, boron can be separated from aqueous samples with Amberlite IRA-743 resin. Experiments on the elute temperature, elute volume and the dynamic resin exchange capacity have been performed in this study. Results show that the dynamic exchange capacity of the resin is 4.2mg B/g and at room temperature, boron fixed on the resin within this capacity level can be extracted quantitatively by using 5ml 2%HNO3. A new procedure has been developed for the measurement of boron isotope ratios in water samples using a Neptune MC-ICP-MS, after resolving the memory effect, which is a key problem, and investigating the impacts of mass bias and Si matrix effect. Using this method, it usually takes 20 min to perform one measurement on 0.1ppm boron solution with a precision of 0.23‰ (SD). If the relative deviation between a sample and the standard is large, the washout time needs to be doubled to achieve a higher precision. δ11B values of water samples from Yangbajing geothermal field vary from -10.53 to -9.13‰. Owing to the large difference B concentration and the small B isotope difference between deep geothermal water and surface water, B isotope ratios of the shallow geothermal fluids are dominated by the deep end member rather than the shallower one in the mixing process. As a consequence, δ11B-B relation is indicative basically of a dilution process. Vapor-liquid separation and calcite scaling also greatly influence B isotope fractionation. δ11B values of water samples from Dagejia geothermal field are from -15.98‰ to -11.67‰. Boron in Changma River near the field has two sources, freshwater lakes (Dajiamang Lake and Canke Lake) and geothermal waters. Finally, a preliminary discussion is included on boron geochemical characteristics of the salt lakes in Shuanghu area and other geothermal fields, to provide information for future studies on boron isotope geochemistry of geothermal systems and salt lakes in Tibet.

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Atmospheric dust as an important factor for climate feedbacks is mainly derived from and drove by the aeolian activities of the semi-arid regions in Asia. Therefore, reconstructing the history of aeolian activities in this region has a great significance in understanding the dynamics of past and future climate changes. This paper made a systematical sedimentology, geochemisty and high-resolution chronology analysis on the sediments from the Xiarinao Lake, which located in Hunshandake Desert, Inner Mongolia, and compared with the meteorological records for identifying the indicator of aeolian activities and climate changes. Based on above work, the evolution history of the aeolian activities and climate changes since 11,000 a BP was reconstructed and the dynamics of the aeolian activities and climate changes in the Hunshandake Desert was discussed. The indicator of aeolian activities was established through the comparison of the clastic and chemical records with the meteorological registers in recent 50 years: 1. The sediments of Xiarinao Lake are mainly derived from eaolian clastic materials and composed of two major components: one is the sand fraction (<4 ) similar to the composition of sand dunes, the other is the silt fraction (>4 ) similar to the atmospheric dust. The sand content and the median grain size, particularly the sand content, show a close association with the intensity of wind, indicating that the particle-size composition of the sediments reflect the variations of the aeolian activities. 2. The proportion of soluble salts relative to the total carbonates in the sediments was correlated to the arid degree registered in meteorological records, suggesting that arid degree might be associated with changes of wind speed and the relative proportion of soluble salts to the total carbonate could be used as the indicator of aridity. 3. The δ18O of authigenic calcite in the Xiarinao Lake show a well correlation with both the atmosphere precipitation and variation of the moisture indicated by the concentrations of soluble salts, suggesting that δ18O of anthigenic calcite is a reliable indicator of humidity. Based on above studies, the evolution history of the aeolian activities and climate changes since 11,000 a BP was reconstructed. At the same time, their association and underlying dynamics was discussed: 1. The evolution history of the eaolian activity was reconstructed by the sand content and median grain size. The result showed that aeolian activities had experienced several different climate periods in the Holocene: the aeolian activities fluctuated with a 500-year cycles during the interval from 10,900 to 8200 a BP; no significant aeolian activities had been developed from 8200 to 6300 a BP; during the interval of 6300 to 2600 a BP, sand content and media grain size had increased gradually, the sand content increased from about 5% to 25%, indicating the intensity of aeolian activity increased in the Hunshandake Desert; since 2600 a BP, intensity of aeolian activity has become stronger and activated the sand dunes. 2. The relative arid degree indicated by the proportion of soluble salts relative to the total carbonate show that both the wind speed and dry degree had being increased since 11,000 a BP. During the interval of 10900 to 6300 a BP, no detectable soluble salt was found in the sediments, indicating the humidity condition; the proportion increased to 20% from 6300 to 4200 a BP, showing the climate became drier; the little change of proportion (20%) suggest that the climate was relative stable during the interval of 4200 to 2600 a BP; after 2600 a BP, the proportion increased, showing the climate became further dry. 3. The δ18O evolution of the lake water was established through analysis of authigenetic calcite δ18O for revealing the variations of relative effective humidity in the Hunshandake Desert. δ18O maintained around -6 ‰ during the interval of 10900 to 8200 a BP, showing the climate was a little dry relative to that of the whole Holocnene; in the period of 8200 to 6300 a BP, δ18O had the most negative values, indicating that it was the most humid interval in Holocene; from 6300 to 4200 a BP, δ18O increased from about -7.5 ‰ to about -3 ‰ gradually, suggesting increased aridity; since 4200 a BP, the climate has become stable and dry. On the whole, the records in this study show that the variation of the relative humidity and aridity is consistent with that of summer monsoon in the Hunshandake Desert. The relationships among the grain size, soluble salts relative content, and the authigenic calcite δ18O indicate aeolian activities is controlled by the aridity in the studied area, and the increased aeolian activities is closely associated with the temperature changes under the relative dry condition. The high wind speed under the low temperature leads to the increased aeolian activity, and the temperature change associated with the aeolian activities might be related with the perturbations of the Siberian High Pressure.

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Organizations are increasingly turning to team-based structures to contend with the pressure of the increasing global competition, consolidation, innovation and need for diverse skills, expertise, and experiences. This ongoing transformation in the basic organization of work has captured the attention of researcher. And group and team research has become increasingly centered in the fields of organizational psychology and organizational behavior since the 1990s. A great deal empirical studies were conducted; a number of variables contributing to team effectiveness and several IPO models were summarized. But teamwork behaviors, the dynamic and adaptive interactions among team members during the task completion, were still very vague. So were the team task characteristics, an important input variable of the IPO models. The effects of team task characteristics and teamwork behaviors on team effectiveness were explored according to IPO model on the basis of the reviews on previous studies, the Hierarchical Conceptual Structure of Teamwork Behaviors (Rousseau et al.,2006), and the task characteristic theory(Hackman & Oldman, 1975). The questionnaire data from 479 team members and 110 team managers of 22 organizations were analyzed. The results indicate: A. Teamwork behaviors consist of 13 behavioral dimensions: team mission analysis, goal specification, planning, coordination, cooperation, information exchange, performance monitoring, backing-up behaviors, intra-team coaching, collaborative problem solving, team practice innovation, psychological support and integrative conflict management. The hierarchical conceptual structure was partly supported with five variable identified, i.e., preparation of work accomplishment, task-related collaborative behaviors, work assessment behaviors, team adjustment behaviors and the management of team maintenance. The formal four variables are in a sequential way. B. The task characteristic theory at individual level is applicable to the team level. This means that the team task characteristics consist of task variety, identity, significance, feedback, autonomy, interdependence. C. The correlations among task characteristics, teamwork behaviors and outcomes support the IPO model. The regulation of team performance mediated the effects of task meaningfulness and interdependence on team outcomes, with the direct effects of task meaningfulness on the preparation behaviors and the direct effects of interdependence on the task-related collaborative behaviors. The management of team maintenance mediated the effects of autonomy on team cohesion and satisfaction. The regulation of team performance has a direct effect on the team performance and the management of team maintenance. And the management of team maintenance has a direct effect on the team attitude and the regulation of team performance.