Due to the limitation of acquisition cost and complex geological conditions, seismic data can not be regularly sampled, so that the seismic data can not meet the actual processing requirements. Spatial irregular data will affect the application effect of stacking and other data processing, which will cause serious spatial aliasing and reduce imaging accuracy.In this paper, a suitableregularization forreverse time migrationis proposed, which is implemented in the OVT domain, with antileakage, antialiasing and antinoise.The output is shot gather by the coordinate mapping relationship. The practical application shows that the technique can effectively improve the imaging accuracy of reverse time migration while saving the acquisition cost.
Extended targets tracking in sea clutter by the video data of radar has gained a special interest recently. The existing methods are not working well with close targets. Misdetection would arise once the close targets are regarded as a large target or a clutter region. Therefore, a rain algorithm is proposed for this problem by separating the measurements of different targets into clusters. The rain algorithm is inspired by the movement of raindrops fall in the mountains. Raindrops would converge into rivers and the mountains would be separated into individual peaks by the rivers. This phenomenon is available to develop a new algorithm providing what is called 'rain algorithm'. In the rain algorithm, the raindrops are designed to find the boundary plots between the closely targets. The rivers are regarded as the boundary of targets and each peak equals a target. The rain algorithm is integrated into the multilevel threshold plot fusion method here and the extra computation is affordable. Both real data and simulated data are performed with the proposed method and several recent methods. The results showcase that the proposed method outperforms the others under various sea conditions.
Through Markov chain and sequential Monte Carlo simulation methods, the reliability model and indexes of the grid connected offshore wind farm, from wind turbines to collection system, collection bus and VSC-HVDC transmission system, are obtained, in which the influence of severe weather, switch configuration of power collection system and different spare strategies of VSC-HVDC are considered. The case study shows that the normal/severe dual weather mode is more conducive to accurately depict the reliability characteristics of offshore wind power system. Meanwhile, the reliability of maximum switch configuration is higher than that of minimum switch configuration. In addition, the cold spare can effectively improve the energy utilization rate and the hot spare can effectively reduce the failure rate of VSC-HVDC system.
With the increasing global energy demand, unconventional oil and gas, especially shale gas, have become an important natural gas resource. In the modern petroleum engineering field, CO2 is commonly used to displace shale gas. CH4 is the main component of shale gas; therefore, understanding the competitive adsorption behavior in the shale matrix is of great significance for optimizing shale gas production. This review explores the competitive adsorption behavior of CH4 and CO2 on a shale matrix from the perspective of molecular simulation and emphasizes the latest research progress in this field. First, several molecular simulation methods for studying gas adsorption are introduced, including density functional theory (DFT), grand canonical Monte Carlo (GCMC), molecular dynamics (MD), coarse-grained molecular dynamics (CGMD), and dissipative particle dynamics (DPD). The competitive adsorption behavior of CO2/CH4 on organic kerogen models, inorganic mineral models, and organic–inorganic composite shale models is discussed, comparing the gas adsorption differences on different shale molecular models. Additionally, the multi-scale simulation methods for shale gas combined with molecular simulations and the application of machine learning (ML) methods are also discussed. Finally, the influence of factors such as the temperature, pressure, moisture content, and pore size on competitive adsorption behavior is analyzed. The challenges and prospects in the current competitive adsorption simulation of CO2/CH4 are summarized, such as constructing shale organic–inorganic composite pore models that combine pore structure and surface chemical heterogeneity and comprehensively considering the multi-scale migration of shale gas from atomic scale to mesoscopic scale to macroscopic scale. This research provides important theoretical support for optimizing the development of natural gas resources and promoting CO2 sequestration technology.
The theoretical system of existing civil engineering typhoon models is too simplified and the simulation accuracy is very low. Therefore, in this work a meso-scale weather forecast model (WRF) based on the non-static Euler equation model was introduced to simulate typhoon “Nuri” with high spatial and temporal resolution, focusing on the comparison of wind direction and wind intensity characteristics before, during and after the landing of the typhoon. Moreover, the effectiveness of the meso-scale typhoon “Nuri” simulation was verified by a comparison between the track of the typhoon center based on minimum sea level pressure and the measured track. In this paper, the aerodynamic performance of large wind turbines under typhoon loads is studied using WRF and CFD nesting technology. A 5 MW wind turbine located in a wind power plant on the southeast coast of China has been chosen as the research object. The average and fluctuating wind pressure distributions as well as airflow around the tower body and eddy distribution on blade and tower surface were compared. A dynamic and time-historical analysis of wind-induced responses under different stop positions was implemented by considering the finite element complete transient method. The influence of the stop position on the wind-induced responses and wind fluttering factor of the system were analyzed. Finally, under a typhoon process, the most unfavorable stop position of the large wind turbine was concluded. The results demonstrated that the internal force and wind fluttering factor of the tower body increased significantly under the typhoon effect. The wind-induced response of the blade closest to the tower body was affected mostly. The wind fluttering factor of this blade was increased by 35%. It was concluded from the analysis that the large wind turbine was stopped during the typhoon. The most unfavorable stop position was at the complete overlapping of the lower blade and the tower body (Condition 1). The safety redundancy reached the maximum when the upper blade overlapped with the tower body completely (Condition 5). Therefore, it is suggested that during typhoons the blade of the wind turbine be rotated to Condition 5.
Today the development of software industry is very fast. The requirement of software and the scope of software application are become widely. So a software product should be installed on different platform and should support different language during the install process. But there are some difficulties to install the product on different platform. This paper research the structure of InstallShield MultiPlatform and show how to use it to create installation program which support multiple platforms and multiple languages.
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