20 resultados para Buck-Boost inverter


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设计了一种用于空间对接缓冲试验台的新型高动态响应助推力模拟装置。介绍了助推装置的机构组成和原理,计算了助推气动系统的响应时间,并分析了助推运动过程。研究表明:该助推装置的响应速度快、精度高,助推力方向实时通过模拟飞行器的质心,满足设计要求。

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The exploration and development of natural gas in the north of Ordos basin have been one important part in China’s energy stratagem. Reservoir in upper Palaeozoic group is of lithological trap and its prediction is a crux in a series of works. Based on foregoing seismic reservoir prediction, seismic data are re-processed with some optical methods and pre-stack information is used in corresponding inversions. Through the application of diverse methods, a series of techniques for reservoir prediction come into being. Several results are achieved as flowing: 1. A set of log processing and interpretation methods is developed. Porosity, permeability and gas saturation models are rebuilt. 2. Based on the petro-physics analysis of reservoirs in upper Palaeozoic group, the equations about lithology, property, hydrocarbon and elastic parameters are established. 3. Forward modeling based on elastic wave theory is first applied in the study area and increases the resolution of modeling results. 4. A series of techniques such as pre-stack time migration and others are combined to improve the data quality. 5. Pre-stack seismic inversion is first employed in the north of Ordos Basin and brings the results of EI, P-impedance, S-impedance and other elastic parameters. 6. In post-stack inversion, logs indicating reservoir parameters are rebuilt and boost the resolution of lithology inversion. 7. Amplitude, coherence, frequency-discomposed amplitude, waveform and other sensitive attributes are extracted to describe sands distribution. Seismic modes standing for sands of P1x3, P1x2 are established. 8. Among 9 proposed wells, 8 wells encountered sands and became production wells. The output of DK13 amounts to 510,000 m3 per day. Keywords:the north of Ordos Basin, reservoir prediction, pre-stack inversion, post-stack inversion, seismic attributes.

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With the development of both seismic theory and computer technology, numerical modeling technology of seismic wave has achieved great advancement during the past half century. The current methods under development include finite differentiation method (FDM), finite element method (FEM), pseudospectral method (PSM), integral equation method (IEM) and spectral element method (SEM). They exert their very important roles in every corner of seismology and seismic prospecting. Large quantity of researches towards spectral element method in the end of last century bring this method to a new era, which results in perfect solution of many difficult problems. However, parts of posterior works such as seismic migration and inversion which base on spectral element method have never been studied widely at least up to the present whereas are of importance to seismic imaging and seismic wave propagation. Based on previous work, this paper uses spectral element method to investigate the characteristics and laws of the seismic wave propagation in isotropic and anisotropic media. By thoroughly studying this high-accuracy method, we implement a kind of reverse-time pre- and post-stack migration based on SEM. In order to verify the validity of the SEM method, we have simulated the propagation of seismic wave in several different models. The simulation results show that: (1) spectral element method can be used to model any complex models and the computational results are comparable with the expected results and the analytic results; (2) the optimum accuracy can be achieved when the rank is between 4 and 9. When it is below 4, the dispersion may occur; and when it is above 9, the time step-length will be changed accordingly with the reducing space step-length in order to keep the computation stability. This will exponentially increase the computation time and at the same time the memory even if simulating the same media. This paper also applies explosive reflection surface imaging technology, time constancy principle of wave-filed extrapolation and least travetime raytracing technology of surface source to SEM pre- and post-stack migration of isotropic and anisotropic media. All imaging results derived by the above methods agree well with the real geological models and the position of interface and inflexions can also return to their right location well. This indicates that the method proposed in this paper is a kind of technology with high accuracy and robust stability. It can serve as an alternative method in real seismic data processing. All these work can boost the development of high-accuracy seismic imaging, and therefore have significant inference value.

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The reservoir of Zhongerbei region in Gudao Oilfield is a typical fluvial facies deposit, its serious heterogeneity of the reservoir caused the distribution of remaining oil in mature reservoirs is characterized by highly scattered in the whole field, and result to declination of production, tap potential and stabilize production is more difficult. Reservoir modeling based on lay scale can not fulfill requirement. How to further studied reservoir heterogeneity within the unit and establish the finer reservoir modeling is a valid approach to oil developing. The architectural structure elements analysis is the effectively method to study reservoir heterogeneity. Utilize this method, divide the reservoirs of Gudao Oilfield into ten hierarchies. The priority studying is sixth, seven hierarchies, ie single sand layers sand bodies By the identification of sixth, seven hierarchies, subdivide the reservoir to the single genetic unit. And to subdivide by many correlation means, such as isometry and phase transition, accomplish closure and correlation of 453 wells.Connectting fluvial deposit pattern, deposition characteristic with its log, build the inverting relation between “sedimentary facies” and “electrofacies” The process emphasize genetic communication and collocation structure of genetic body in space. By detailed architecture analyses sandbodies’ structure, this paper recognize seven structure elements, such as major channel, abandoned channel, natural levee, valley flat, crevasse splay, crevasse channel and floodplain fine grain.Combination identification of architectural structure elements with facieology and study of deposition characteristic, can further knowing genesis and development of abandoned channel. It boost the accuracy to separation in blanket channel bodies distribution, and provide reference to retrieving single channel boundary. Finally, establish fine plane and section construction. On basis architectural structure map, barrier beds and interbeds isopach map and mini-structure map, considering single thin layers to be construction unit, the main layer planimetric maps have drawn and the inner oil-water boundary have revealed. All account that architectural structure elements control remaining oil distribution in layer, and develop the study on architectural structure elements to direct horizontal well is succesful.

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Work engagement (WE) has recently become a fashionable term among Human Resource practitioners and Organizational Behavior researchers. However, academic research that has theoretically examined WE at the psychological level is limited, as is research on its place among other job attitude constructs that are used to describe employees at work, and its antecedents and consequences. This dissertation addresses a number of issues with regard to the discriminant validity of WE, the influences of WE and the mediating role of affective commitment, and the interaction effects of different job demands, job resources and personal resources on WE. The major findings are listed as follows: Firstly, the concept of WE is different from JB and job involvement (JI), and is more positively related to quality of employees’ work and life than the other two concepts. Specifically, WE is more related to employees’ creative performance than JB does; compared with JI, WE can better predict task performance, creative performance, organizational citizenship behavior (OCB), and life satisfaction; although both WE and JB cause work to family conflict, WE improves employees’ life satisfaction, while JB is deleterious to life satisfaction. Secondly, WE influences employees’ work and life directly or through the mediation effect of affective commitment. Specifically, WE reduces employees’ turnover intention and increase their OCBs by the the mediation effect of effective commitment. Furthermore, WE is positively related to task performance, creative performance, and life satisfaction directly. Thirdly, challenge job demands influence WE by the mediation effect of intrinsic motivation, and the impact of challenge job demands on WE is moderated by perceived supervisor support and growth needs. Specifically speaking, challenge job demands enhance employees’ intrinsic motivation, therefore boost WE. Employees with higher growth needs are more likely to be motivated by challenge job demands. In other words, the moderation effect of growth need is mediated by intrinsic motivation. In addition, those who perceive more supervisor support have higher level of WE when challenge job demands are high.