We propose a new automatic method for the interpretation of potential fi eld data, called the RDAS–Euler method, which is based on Euler＇s deconvolution and analytic signal methods. The proposed method can estimate ...We propose a new automatic method for the interpretation of potential fi eld data, called the RDAS–Euler method, which is based on Euler＇s deconvolution and analytic signal methods. The proposed method can estimate the horizontal and vertical extent of geophysical anomalies without prior information of the nature of the anomalies（structural index）. It also avoids inversion errors because of the erroneous choice of the structural index N in the conventional Euler deconvolution method. The method was tested using model gravity anomalies. In all cases, the misfi t between theoretical values and inversion results is less than 10%. Relative to the conventional Euler deconvolution method, the RDAS–Euler method produces inversion results that are more stable and accurate. Finally, we demonstrate the practicability of the method by applying it to Hulin Basin in Heilongjiang province, where the proposed method produced more accurate data regarding the distribution of faults.展开更多
With the data of daily precipitation and daily evaporation,dynamic drought index was calculated and compared with the identification standard of drought grade to qualify the severity of drought.According to the dynami...With the data of daily precipitation and daily evaporation,dynamic drought index was calculated and compared with the identification standard of drought grade to qualify the severity of drought.According to the dynamic drought index,a regional drought identifying system was developed for the watershed between the reach of the Yangtze River and Huaihe River in Anhui Province by using VC++ working platform and Access database.This drought identifying system would be very useful to forecast and early warn the happening of drought in this area.展开更多
文摘目的孤立性肺结节(solitary pulmonary nodule,SPN)的定性诊断十分困难,PET/CT是目前评价良、恶性病变最具优势的影像学手段之一。文中用Meta分析方法综合评价18F-脱氧葡萄糖(18Fluorodexglucose,FDG)PET/CT显像诊断恶性孤立性肺结节的价值。方法以孤立性肺结节、FDG、PET/CT等为检索词,检索1994年1月至2009年7月的Medline数据库、西文生物医学期刊文献服务系统、外文生物医学期刊全文数据库、中国学术期刊网全文数据库等相关中英文文献。对符合标准的研究进行质量评估,用MetaDisc1.4软件进行异质性检验,综合敏感性、特异性和诊断优势比,绘制汇总受试者工作特征(summary receiver operating characteristic,SROC)曲线和计算曲线下面积(the area under the curve,AUC),并进行敏感性分析。结果共检索相关文献29篇,其中11篇符合标准纳入分析,A级1篇,B级10篇,各研究之间存在异质性,按照随机效应模型合并敏感性、特异性、诊断优势比(diagnostic odds ratio,DOR)及其95%可信区间分别为91%(87%~93%)、83%(78%~87%)和51.04(23.33~111.66),AUC为0.9383,Q值为0.875 3,纳入文献稳定性较好。结论 18F-FDG PET/CT显像能灵敏、准确地诊断恶性孤立性肺结节,具有较高的临床应用价值。
基金supported by the National High Technology Research and Development Program of China(No.2006AA06A208)
文摘We propose a new automatic method for the interpretation of potential fi eld data, called the RDAS–Euler method, which is based on Euler＇s deconvolution and analytic signal methods. The proposed method can estimate the horizontal and vertical extent of geophysical anomalies without prior information of the nature of the anomalies（structural index）. It also avoids inversion errors because of the erroneous choice of the structural index N in the conventional Euler deconvolution method. The method was tested using model gravity anomalies. In all cases, the misfi t between theoretical values and inversion results is less than 10%. Relative to the conventional Euler deconvolution method, the RDAS–Euler method produces inversion results that are more stable and accurate. Finally, we demonstrate the practicability of the method by applying it to Hulin Basin in Heilongjiang province, where the proposed method produced more accurate data regarding the distribution of faults.
基金Supported by Special Fund for Public Welfare Meteorology Industry (GYHY201106029)
文摘With the data of daily precipitation and daily evaporation,dynamic drought index was calculated and compared with the identification standard of drought grade to qualify the severity of drought.According to the dynamic drought index,a regional drought identifying system was developed for the watershed between the reach of the Yangtze River and Huaihe River in Anhui Province by using VC++ working platform and Access database.This drought identifying system would be very useful to forecast and early warn the happening of drought in this area.
