320排/64排CTA和DSA诊断颅内动脉瘤原理和应用比较研究

目的:通过对320排、64排CTA以及DSA诊断颅内动脉瘤的原理和应用进行比较研究,达到选择最合适检查方法的目的。方法:收集86例颅内动脉瘤患者分别釆用320排CTA、64排CTA和3D DSA检查,研究并比较CTA和DSA影像特点。结果:86例动脉瘤患者经320排CTA诊断动脉瘤92个,64排CTA诊断90个,3D DSA诊断96个,以X2检查比较,所得数据均釆用SPSS16.0统计学软件处理,相似文献   

Mapping sediment-dispersal characteristics using seismic geomorphology: Late Paleogene to Neogene,Qinan Sag,Huanghua Depression,China

The main objective of this article has been to demonstrate the utility of stratal slice images for exploring the sequence stratigraphy and sedimentology of complex depositional systems. The seismic-geomorphology study and sedimentary interpretation were performed to map sediment-dispersal characteristics from late Paleogene to Neogene in Qinan Sag, located in Huanghua Depression of China. The Qinan Sag is underlain by a non-marine Mesozoic and Cenozoic-age stratigraphic section. Main data types in this study area are lithology, wire-line logs and 3D seismic. The main study strata, Member one of Shahejie Formation to Minghuazhen Formation, divided into two second-order sequences and four third-order sequences. The older of the two second-order sequences, SE, corresponds to the formations from Kongdian to Dongying. The younger of the two second-order sequences, SN, correspond to Guantao and Minghuazhen formations. Guided by third-order sequence-stratigraphic correlations from seismic and wireline-log data, we prepared stratal slices from a three-dimensional seismic volume to reveal high-resolution (10-m) sediment dispersal characteristics in a relative geologic-time domain. Using techniques of 3-D seismic geomorphology, we defined four types of depositional systems: braided deltas, deltas, braided rivers and meandering rivers. Stratal slices indicated that the depositional evolution of these interest sequences was from braided-delta front to delta front, braided river and finally meandering river system. Many factors related to the structural evolution history controlled the sediment-dispersal characteristics, such as the basin type, dynamic mechanism, faulting activity, subsidence rate and paleo-high.     

基于土条周边水压力分析的水下滑体稳定性研究

在水库运营过程中,水库涉水滑坡会有部分滑体没在水下,在采用传力系数法进行滑坡稳定性计算时,滑坡稳定性系数与水下条块的水压力紧密相关。在分析极限平衡法中水上岩土体水压力及渗透力计算方法的基础上,通过水下三角形条块和四边形条块的水压力计算,探讨了传力系数法中位于水下条块的抗滑力及下滑力的计算方法,得出了水下滑体的抗滑力和下滑力只与浮重力的大小有关,与浸没在水下深度的变化无关的结论。研究成果简化了水压力的计算,对水下滑体水压力及稳定性计算具有重要的参考和借鉴意义。     

“特殊”煤光片制备及对煤岩分析的主要影响

煤岩分析在煤相研究、地质勘查、炼焦配煤等诸多方面有广泛应用;合格的煤光片是煤岩分析的前提。为解决易碎裂样品、老化煤光片等\     

实用地球物理技术在渤中探区岩性勘探中的应用

针对渤中探区Q构造新近系近十年探索没有取得突破性进展,借鉴周边成熟油田浅层岩性勘探的思路,以地质认识为指导,以精细构造解释和岩性圈闭刻画为核心,综合运用地层切片、地震属性分析、90度相移及低幅度构造变速成图等多项地球物理技术,对新近系明下段浅水三角洲岩性圈闭进行精细识别与刻画.结果表明：地层切片结合地震属性技术有效识别砂体平面展布特征,90度相移技术辅助完成砂体精细刻画,低幅度构造变速成图技术真实反映砂体构造特征.通过多项地球物理技术的应用,相继发现了Qa、Qb/c及Qd等一系列浅层岩性含油气构造,掀起了渤海海域浅层岩性勘探的热潮,同时也对相似地质背景探区具有借鉴意义.     

Simulation of Suspended Sediment in the Yellow and East China Seas

Described is an initial attempt to simulate the suspended sediment dynamics relating to tidal and wave forcing during summertime in June 1980 and August 1981 for the Yellow and East China Seas continental shelf. The cohesive/non-cohesive sediment resuspension and movement generated by the interaction between current and wave are modeled by use of ECOMSED and WAM Cycle 4. Model results are compared with observations in US-China Marine Sedimentation Dynamics Program performed for 1980-81 at off the Changiiang estuary. The main features of simulations show that suspended sediment concentrations during the summer decreased markedly offshore as observed during the simulation periods. As for some discrepancies for the mouth of the estuary with high river discharges, i.e., the Changjiang River, the model did not properly reproduce the over-mixing situation in the summer; thus distinct vertical concentration variation in this local region is not agreeable with observation. However, general dispersal patterns of suspended sediment movement seem to be agreeably reproduced for the nearshore shallow region. Some of the procedures of simulation and results are presented and discussed.     

造山带断片型地层层序恢复实例剖析

南皮河组和怕拍组分布于昌宁一孟连带西缘的耿马、沧源、澜沧地区,前人将其分别划归晚二叠世和早三叠世。新的研究表明,它们不是连续地层,而是由多个地层断片组成。通过逐个地层断片研究,恢复了该区被动陆缘的地层序列。在此基础上,重新进行地层划分,厘定了弄巴组、南皮河组和怕拍组。进而探讨了该被动陆缘的演化历史。     

海洋深水水道地震综合解释技术研究——以南海北部陆坡区更新统深水水道为例

深水沉积是深水油气勘探的重要领域.本文利用南海北部陆坡区三维地震资料,应用三维可视化、相干处理、沿层切片及波形分类等地震技术,识别和刻画南海北部陆坡区更新世深水沉积水道的展布、演化特征及有利砂体分布位置,初步总结出一套适合深水沉积水道的地震识别和描述方法.该水道呈南西-北东方向展布、具蛇曲形态,水道主体以泥岩充填为主,水道侧向加积及堤坝部位是有利的储集部位.     

滑坡-碎屑流运动过程铲刮效应分析

通过采用垂直条分法把滑坡-碎屑流沿滑动方向等分为不同的部分,运用不平衡推力法求出滑坡-碎屑流失稳时滑块之间的初始条间力和初始加速度,计算得出滑坡-碎屑流的启动初速度。在滑坡运动过程中,运用Voellmy模型和摩尔库伦准则求出滑坡-碎屑流的铲刮深度,结合弹簧滑块模型可以得到运动过程中不同时刻滑块间的速度。通过不断迭代的方法当每个滑块的速度为零时,滑坡-碎屑流停止运动,此时即可得到滑坡-碎屑流的铲刮距离和铲刮长度。为了验证模型的正确性和实用性,用本文的计算结果和滑坡冲击铲刮试验的结果进行了对比结果比较吻合。     

地震条件下黏性土挡土墙土压力分析

Mononobe-Okabe理论是现阶段计算地震土压力的常用方法,但Mononobe-Okabe理论的诸多假设使其具有一定的局限性。针对Mononobe-Okabe理论的不足,考虑到地震作用下挡土墙偏转对土压力的影响,采用斜向条分法推导了复杂条件下黏性土地震土压力强度分布、土压力合力及其作用点位置公式,并利用图解法给出了临界破裂角的解析解。研究表明：填土黏聚力和地震系数对土压力影响显著;忽略黏性填土表面开裂与地震作用对均布超载及开裂填土等效超载的影响将使主动土压力计算结果偏小,其误差随着填土黏聚力和均布超载的增大而增大;在不同水平地震系数下土压力沿墙高呈非线性分布;所提公式适用范围更广,有效完善了Mononobe-Okabe理论。