The conventional method of seismic data acquisition geometry design is based on the assumption of horizontal subsurface reflectors, which often is not suitable for complex structure. We start from a controlled illumin...The conventional method of seismic data acquisition geometry design is based on the assumption of horizontal subsurface reflectors, which often is not suitable for complex structure. We start from a controlled illumination analysis and put forward a method of seismic survey geometry design for target-oriented imaging. The method needs a velocity model obtained by a preliminary seismic interpretation. The one-way Fourier finite-difference wave propagator is used to extrapolate plane wave sources on the target layer to the surface. By analyzing the wave energy distribution at the surface extrapolated from the target layer, the shot or receiver locations needed for target layer imaging can be determined. Numerical tests using the SEG-EAGE salt model suggest that this method is useful for confirming the special seismic acquisition geometry layout for target-oriented imaging.展开更多
目的检索并总结肝癌切除手术患者目标导向性血糖监测相关证据,为临床提供指导依据。方法应用PICO程式结构化临床问题,检索中国指南网,美国指南网,英国国家临床医学研究所指南库,国际指南图书馆,英格兰学院间指南网,UpToDate,BMJ,Cochran...目的检索并总结肝癌切除手术患者目标导向性血糖监测相关证据,为临床提供指导依据。方法应用PICO程式结构化临床问题,检索中国指南网,美国指南网,英国国家临床医学研究所指南库,国际指南图书馆,英格兰学院间指南网,UpToDate,BMJ,Cochrane Library,PubMed,Web of Science,EMbase,CINAHL,中国生物医学数据库,中国知网,万方医学数据库。采用相关评价工具对纳入的文献进行质量评价。结果共纳入文献15篇,包括指南6篇,专家共识3篇,原始研究6篇,总结出18条审查指标,包括多学科团队构建、术前评估及健康教育、监测方法、术前/术中/术后目标导向性血糖监测措施、异常血糖处理、术后交接及管理等内容。结论本研究总结了肝癌切除手术患者目标导向性血糖监测的最佳证据,为规范临床血糖监测及控制,降低血糖异常事件及并发症发生率,加速术后康复提供循证依据。展开更多
For large-scale 3D seismic data,target-oriented reservoir imaging is more attractive than conventional full-volume migration,in terms of computation efficiency.Gaussian beam migration(GBM)is one of the most robust dep...For large-scale 3D seismic data,target-oriented reservoir imaging is more attractive than conventional full-volume migration,in terms of computation efficiency.Gaussian beam migration(GBM)is one of the most robust depth imaging method,which not only keeps the advantages of ray methods,such as high efficiency and flexibility,but also allows us to solve caustics and multipathing problems.But conventional Gaussian beam migration requires slant stack for prestack data,and ray tracing from beam center location to subsurface,which is not easy to be directly applied for target-oriented imaging.In this paper,we modify the conventional Gaussian beam migration scheme,by shooting rays from subsurface image points to receivers to implement wavefield back-propagation.This modification helps us to achieve a better subsurface illumination in complex structure and allows simple implementation for target reservoir imaging.Significantly,compared with the wavefi eld-based GBM,our method does not reconstruct the subsurface snapshots,which has higher efficiency.But the proposed method is not as efficient as the conventional Gaussian beam migration.Synthetic and field data examples demonstrate the validity and the target-oriented imaging capability of our method.展开更多
文摘The conventional method of seismic data acquisition geometry design is based on the assumption of horizontal subsurface reflectors, which often is not suitable for complex structure. We start from a controlled illumination analysis and put forward a method of seismic survey geometry design for target-oriented imaging. The method needs a velocity model obtained by a preliminary seismic interpretation. The one-way Fourier finite-difference wave propagator is used to extrapolate plane wave sources on the target layer to the surface. By analyzing the wave energy distribution at the surface extrapolated from the target layer, the shot or receiver locations needed for target layer imaging can be determined. Numerical tests using the SEG-EAGE salt model suggest that this method is useful for confirming the special seismic acquisition geometry layout for target-oriented imaging.
文摘目的检索并总结肝癌切除手术患者目标导向性血糖监测相关证据,为临床提供指导依据。方法应用PICO程式结构化临床问题,检索中国指南网,美国指南网,英国国家临床医学研究所指南库,国际指南图书馆,英格兰学院间指南网,UpToDate,BMJ,Cochrane Library,PubMed,Web of Science,EMbase,CINAHL,中国生物医学数据库,中国知网,万方医学数据库。采用相关评价工具对纳入的文献进行质量评价。结果共纳入文献15篇,包括指南6篇,专家共识3篇,原始研究6篇,总结出18条审查指标,包括多学科团队构建、术前评估及健康教育、监测方法、术前/术中/术后目标导向性血糖监测措施、异常血糖处理、术后交接及管理等内容。结论本研究总结了肝癌切除手术患者目标导向性血糖监测的最佳证据,为规范临床血糖监测及控制,降低血糖异常事件及并发症发生率,加速术后康复提供循证依据。
文摘For large-scale 3D seismic data,target-oriented reservoir imaging is more attractive than conventional full-volume migration,in terms of computation efficiency.Gaussian beam migration(GBM)is one of the most robust depth imaging method,which not only keeps the advantages of ray methods,such as high efficiency and flexibility,but also allows us to solve caustics and multipathing problems.But conventional Gaussian beam migration requires slant stack for prestack data,and ray tracing from beam center location to subsurface,which is not easy to be directly applied for target-oriented imaging.In this paper,we modify the conventional Gaussian beam migration scheme,by shooting rays from subsurface image points to receivers to implement wavefield back-propagation.This modification helps us to achieve a better subsurface illumination in complex structure and allows simple implementation for target reservoir imaging.Significantly,compared with the wavefi eld-based GBM,our method does not reconstruct the subsurface snapshots,which has higher efficiency.But the proposed method is not as efficient as the conventional Gaussian beam migration.Synthetic and field data examples demonstrate the validity and the target-oriented imaging capability of our method.