When cause of the aliasing lack probl using borehole sensors and microseimic events to image, spatial aliasing often occurred be- of sensors underground and the distance between the sensors which were too large. To so...When cause of the aliasing lack probl using borehole sensors and microseimic events to image, spatial aliasing often occurred be- of sensors underground and the distance between the sensors which were too large. To solve em, data reconstruction is often needed. Curvelet transform sparsity constrained inversion was widely used in the seismic data reconstruction field for its anisotropic, muhiscale and local basis. However, for the downhole ease, because the number of sampling point is mueh larger than the number of the sensors, the advantage of the cnrvelet basis can＇t perform very well. To mitigate the problem, the method that joints spline and curvlet-based compressive sensing was proposed. First, we applied the spline interpolation to the first arri- vals that to be interpolated. And the events are moved to a certain direction, such as horizontal, which can be represented by the curvelet basis sparsely. Under the spasity condition, curvelet-based compressive sensing was applied for the data, and directional filter was also used to mute the near vertical noises. After that, the events were shifted to the spline line to finish the interpolation workflow. The method was applied to a synthetic mod- el, and better result was presented than using curvelet transform interpolation directly. We applied the method to a real dataset, a mieroseismic downhole observation field data in Nanyang, using Kirchhoff migration method to image the microseimic event. Compared with the origin data, artifacts were suppressed on a certain degree.展开更多
目的探讨颅内压监测对重度颅脑外伤开颅血肿清除术后患者GCS评分、并发症及预后的影响。方法选取重度颅脑外伤患者84例,将以上患者分成常规组和监测组。常规组患者行标准外伤大骨瓣开颅减压术,监测组患者则在行标准外伤大骨瓣开颅减压...目的探讨颅内压监测对重度颅脑外伤开颅血肿清除术后患者GCS评分、并发症及预后的影响。方法选取重度颅脑外伤患者84例,将以上患者分成常规组和监测组。常规组患者行标准外伤大骨瓣开颅减压术,监测组患者则在行标准外伤大骨瓣开颅减压术的基础上联合术后颅内压监测。比较2组患者手术前后格拉斯哥昏迷评分(GCS)、颅内压变化、术后并发症发生情况以及预后。结果监测组患者术后3、7 d的颅内压下降值显著大于常规组(P<0.05);2组患者术后28 d GCS评分均显著升高,且监测组患者GCS评分升高较常规组更显著(P<0.05);与常规组相比,术后3个月的格拉斯哥预后评分(GOS)提示监测组的预后较好(P<0.05);术后6个月,常规组与监测组的电解质紊乱发生率分别为59.5%、33.3%(P<0.05)。结论对重度颅脑外伤患者行标准外伤大骨瓣开颅减压术联合术后颅内压监测的疗效较好。展开更多
基金Supported by Project of the National Natural Science Foundation of China(No.41274055)
文摘When cause of the aliasing lack probl using borehole sensors and microseimic events to image, spatial aliasing often occurred be- of sensors underground and the distance between the sensors which were too large. To solve em, data reconstruction is often needed. Curvelet transform sparsity constrained inversion was widely used in the seismic data reconstruction field for its anisotropic, muhiscale and local basis. However, for the downhole ease, because the number of sampling point is mueh larger than the number of the sensors, the advantage of the cnrvelet basis can＇t perform very well. To mitigate the problem, the method that joints spline and curvlet-based compressive sensing was proposed. First, we applied the spline interpolation to the first arri- vals that to be interpolated. And the events are moved to a certain direction, such as horizontal, which can be represented by the curvelet basis sparsely. Under the spasity condition, curvelet-based compressive sensing was applied for the data, and directional filter was also used to mute the near vertical noises. After that, the events were shifted to the spline line to finish the interpolation workflow. The method was applied to a synthetic mod- el, and better result was presented than using curvelet transform interpolation directly. We applied the method to a real dataset, a mieroseismic downhole observation field data in Nanyang, using Kirchhoff migration method to image the microseimic event. Compared with the origin data, artifacts were suppressed on a certain degree.
文摘静电层析成像(Electrostatic tomography,EST)技术因其无辐射、非入侵、可视化、实时性高、成本低等优势在滑油磨粒在线监测中获得广泛研究,但实际测量中静电信号幅值微弱且含有大量噪声,严重影响图像重建质量。针对上述问题,本文提出一种基于稀疏分解的静电信号降噪方法。首先,对EST传感器测量得到的静电信号数据构建相应的字典,然后用正交匹配追踪(OMP)算法在字典中寻找信号的稀疏表示矩阵,并用其与字典的乘积来表示信号,最后将稀疏表示后的信号代入基于原始对偶内点法(PDIPA)的EST图像重建,并与两种经典降噪方法进行对比。实验结果表明:经过数据降噪处理,重建图像误差相对于降噪前下降5.5%,相对于小波分析或经验模态分解(Empirical Mode De composition,EMD)方法具有较高的准确性;采用本文提出的降噪方法,明显提高了管道内单个荷电颗粒和两个荷电颗粒在不同径向位置时的成像质量。
文摘目的探讨颅内压监测对重度颅脑外伤开颅血肿清除术后患者GCS评分、并发症及预后的影响。方法选取重度颅脑外伤患者84例,将以上患者分成常规组和监测组。常规组患者行标准外伤大骨瓣开颅减压术,监测组患者则在行标准外伤大骨瓣开颅减压术的基础上联合术后颅内压监测。比较2组患者手术前后格拉斯哥昏迷评分(GCS)、颅内压变化、术后并发症发生情况以及预后。结果监测组患者术后3、7 d的颅内压下降值显著大于常规组(P<0.05);2组患者术后28 d GCS评分均显著升高,且监测组患者GCS评分升高较常规组更显著(P<0.05);与常规组相比,术后3个月的格拉斯哥预后评分(GOS)提示监测组的预后较好(P<0.05);术后6个月,常规组与监测组的电解质紊乱发生率分别为59.5%、33.3%(P<0.05)。结论对重度颅脑外伤患者行标准外伤大骨瓣开颅减压术联合术后颅内压监测的疗效较好。
