An approximation to the P-wave reflection coefficient for amplitude variation with long-offset seismic data

In recent years, long-offset exploration has been widely used, especially on marine seismic surveys. Conventional AVO analysis is insufficient for long-offset seismic data. To widen the application range of AVO analysis, we present a new P-wave reflection coefficient approximation applicable to long-offset data. Our result is similar to the well known Shuey formula which can be treated as an approximation to our results for short-offset seismic data.

眼球钝挫伤的图形视诱发电位

为寻找眼钝挫伤后评价视神经损伤情况的客观敏感的指标，应用Ｎｅｕｒｏｐａｃｋ８型诱发电位检测仪对５１例（５１眼）眼球钝挫伤病人和１６名（３２眼）正常人进行ＰＶＥＰ检测。挫伤眼ＰＶＥＰ的Ｐ波时值和幅值较钝挫伤患者的对侧健眼和正常组均有显著差异（Ｐ＜０．０１）。且视力≤０．４者较视力≥０．５者的时值明显延长（Ｐ＜０．０１）。结论：挫伤眼存在明显的视信息量传输障碍，其神经兴奋传输速度和反应强度均明显下降。认为ＰＶＥＰ是眼球钝挫伤后视神经损伤程度判定的敏感而客观的指标。