脑血管病变多层螺旋CT血管造影三维成像技术的应用

目的:评估多层螺旋CT血管造影在脑血管疾病诊治中的价值.方法:对20例脑血管病患者进行CT血管造影检查,应用后处理工作站进行脑血管三维重建,显示病变解剖关系.结果:全部20例病变其中动脉瘤10例,动静脉畸形8例,脑血管狭窄2例均经手术及DSA证实.其中一例动脉瘤手术证实,DSA未检出.结论:CT血管造影三维重建可全方位显示脑血管,具有微创、安全、可靠、费用低廉等特点,适合于手术计划制定、术前定位及随访.     

松辽盆地白垩纪青山口阶的同位素地层标志及其与海相Cenomanian阶的对比

本研究利用大庆油田在松辽盆地中部的岩心样品进行了青山口组有机碳稳定同位素的测试,通过化学地层和生物地层研究提出了青山口阶的顶底标志。在青山口组底部同位素值最低,为- 32 .2‰,与介形虫Cypridea elliptica的消失界面吻合。同位素值随后迅速上升,形成底界之上的第一个峰值,为- 2 8.1‰。随后的4个峰值自下而上分别是- 2 8‰、- 2 7.8‰、- 2 7.3‰和- 2 6 .6‰,相间的低峰值一般处于- 30‰～- 2 9‰左右。最为重要的是,有机碳稳定同位素值在青山口组顶部出现一个明显的异常,由- 2 9.5‰急剧升为- 2 3.1‰,随后又迅速降为- 30 .12‰,形成一个明显的正向峰值。这一正向偏移的位置与介形类Cypridea panda和Triangulicyprisfusiformis的消失界面基本吻合,并与全球Cenom anian- Turonian界线稳定同位素事件表现一致。据此,将这一稳定同位素正向偏移确定为青山口阶顶界的化学标志。通过这一标志可以将青山口阶的顶界与海相Cenom anian阶顶界进行对比。研究结果表明,化学地层标志是陆相与海相地层的对比的渠道。青山口阶的有机碳稳定同位素值具有全球一致的意义,与我国西藏南部海相地层,乃至全球重要地区Cenomanian- Turonian阶稳定同位素界线均具有可比性。     

Revision of the Clam Shrimp Genus Magumbonia from the Upper Jurassic of the Luanping Basin,Hebei,Northern China

The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China.Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin,northern Hebei,China,is revised on the basis of a scanning electron microscope (SEM) examination of the type species M.jingshangensis Wang,1984,which revealed morphological features not recognized previously.These include coarse reticulation on the umbo and promi...     

宜万铁路野三关隧道“8.5”突水事故成因分析

2007年8月5日宜(昌)万(州)铁路野三关隧道发生了重大的岩溶突水事故.在岩溶水文地质调查的基础上,对野三关隧道所处流域两个主要岩溶洼地以NaCl为示踪剂进行了充水水源和充水途径的示踪试验.两次示踪试验结果查明水洞坪岩溶洼地是"8.5"突水事故的主要水源,茅口组灰岩中发育的周家包暗河被F18断裂切割,将暗河水导入隧道形成突水事故.稻子坪的水在隧道突水段西以渗-涌水的形式进入隧道.水洞坪示踪实验得出二叠系栖霞-茅口组岩溶含水层中的地下水流速为50 m/h.稻子坪示踪试验得到茅口组灰岩含水层中的地下水流速为45.5 m/h;大冶组灰岩含水层中的地下水流速为10.8 m/h.本示踪结果为宜万铁路野三关隧道的后期恢复施工和防渗工作提供了依据,并为岩溶地区深埋隧道的设计和施工提供了试验和分析工作的实例参考.     

福建大田城西水厂供水井找水及施工方法

简述大田县城西水厂供水井水源地寻找．及施工工艺和钻进方法,首先采用小口径探孔、再抽水试验、水质分析等,当各项指标均符合要求后,再进行大口径的供水井施工,达到预期水量、水质要求。该大水量供水井的找水及钻探方法,可降低风险,节约成本,提高效益。     

锆铝基柱撑蒙脱土的制备研究

以钠基蒙脱土为原料,采用共聚法合成锆铝基柱撑蒙脱土,并研究不同锆铝摩尔比例和不同NaOH的量对柱撑蒙脱土制备的影响。XRD研究表明,当锆铝摩尔比例为1：6、加入70ml0．4mol／LNaOH时,可得到（001）面网层间距达1．9343nm的锆铝基柱撑蒙脱土。通过FT—IR发现,锆铝聚合羟基阳离子进入蒙脱土层间,形成Si-O-Al和Si-O-Zr。对柱撑前后蒙脱土的比表面积和孔径结构进行分析,发现锆铝基柱撑蒙脱土具有较大的比表面积,较为均匀的孔径分布,是一种合适的催化和吸附材料。     

冰雷达探测研究南极冰盖的进展与展望

南极冰盖是地球上最大的陆缘冰体,其物质收支和稳定性对全球气候变化和海平面升高有重要的影响。冰雷达,或称无线电回波探测,是冰川学家调查南极冰盖冰下特征的主要方法。在过去的50年里,冰雷达被广泛用于测量冰盖厚度、内部构造和冰下地貌,这些参数是计算冰盖体积和物质平衡、重建过去冰雪积累和消融率以及冰盖动力和沉积过程的基础。现在,冰雷达测量覆盖了南极绝大部分区域,极大地提升了人们对南极冰盖和全球系统间相互作用的理解。首先,简要介绍了冰雷达及其技术发展,然后着重评述了冰雷达在探测研究南极冰盖厚度和冰下地形、内部反射层、冰下湖和冰下水系、冰床粗糙度以及冰晶组构上的进展。最后,对未来冰雷达探测研究南极冰盖的前景进行了展望,并给出我国的现状。
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Crustal Structure beneath Yinggehai Basin and Adjacent Hainan Island, and Its Tectonic Implications

Two NE-SW trending wide-angle seismic profiles were surveyed across the Chinese side Two NE-SW trending wide-angle seismic profiles were surveyed across the Chinese side of the Yinggehai (莺歌海) basin (YGHB) with ocean bottom hydrophones (OBHs) and piggyback recorded by onshore stations located on the Hainan (海南)Island.Detailed velocity-depth models were obtained through traveltime modeling and partially constrained by amplitude calculations.More than 15 km Tertiary sedimentary infill within the YGHB can be divided in to three layers with distinct velocity-depth distribution.Overall,the upper layer has a high velocity gradient with 3.8-4.1 km/s at its bottom,consistent with progressive compaction and diagenesls.Its thickness increases gradually towards the basin center,reaching 4.5 km along the southern profile.The middle layer is characterized in its most part as a pronounced low velocity zone (LVZ) with average velocity as low as 3.0 km/s.Its thickness increases from 3.0 to over 4.5 km from NW towards SE.The primary causes of the velocity inversion are high accumulation rate and subsequent under-compaction of sediments.The velocity at the top of the lower layer is estimated at about 4.5 km/s.Despite strong energy source used (4 x 12L airgun array),no reflections can be observed from deeper levels within the basin.Towards NE the basin is bounded sharply by a clear and deep basement fault (Fault No.1),which seems to cut through the entire crust.A typical continental crust with low-velocity middle crust is found beneath the coast of the western Hainan Island.Its thickness is determined to be 28 km and shows no sign of crustal thinning towards the basin.The sharp change in crustal structure across Fault No.1 indicates that the fault is a strike-slip fault.The crustal structure obtained in this study clearly favors the hypothesis that the YGHB is a narrow pull-apart basin formed by strike-slip faulting of the Red River fault zone.     

High-Frequency Rayleigh-Wave Method

High-frequency (≥2 Hz) Rayleigh-wave data acquired with a multichannei recording sys-tem have been utilized to determine shear (S)-wave velocities in near-surface geophysics since the early 1980s. This overview article discusses the main research results of high-frequency surface-wave tech-niques achieved by research groups at the Kansas Geological Survey and China University of Geosciences in the last 15 years. The multichannel analysis of surface wave (MASW) method is a nou-iuvasive acoustic approach to estimate near-surface S-wave velocity. The differences between MASW results and direct borehole measurements are approximately 15% or less and random. Studies show that simultaneous inversion with higher modes and the fundamental mode can increase model resolution and an investigation depth. The other important seismic property, quality factor (Q), can also be estimated with the MASW method by inverting attenuation coefficients of Rayleigh waves. An inverted model (S-wave velocity or Q) obtained using a damped least-squares method can be assessed by an optimal damping vector in a vicinity of the inverted model determined by an objective function, which is the trace of a weighted sum of model-resolution and model-covariance matrices. Current developments include modeling high-frequency Rayleigh-waves in near-surface media, which builds a foundation for shallow seismic or Rayleigh-wave inversion in the time-offset domain; imaging dispersive energy with high resolution in the frequency-velocity domain and possibly with data in an arbitrary acquisition geometry, which opens a door for 3D surface-wave techniques; and successfully separating surface-wave modes, which provides a valuable tool to perform S-wave velocity profiling with high-horizontal resolution.     

城市土地潜力分析--以南京市为例

研究城市土地潜力是城市建设者合理利用城市土地、提高城市土地利用效率、保护耕地的基础。该文利用GIS对土地、规划、环保、人口等相关数据进行整合,从房地产开发的角度建立测算最低经济容积率的模型,求得每块城市土地的经济容积率;基于GIS空间分析功能,分析城市土地利用现状与最低经济容积率,并用地域环境质量综合评价、历史文化名城保护规划等数据对结果进行修正,得出南京市城市土地潜力的数量、质量及空间分布。