MRI对鼻咽癌、颅底转移及放疗中、后改变的诊断与评价

目的：探讨MRI对及MRI对放疗中、放疗后改变及放疗后残存与复安全的保障价值。材料与方法：搜集30进行放疗前、放疗中及放疗后的MRI检查。放疗后状态的病例均追随3-6个月复查。结果：在30例鼻咽癌患者中,存在颅底骨骨转移病例1例。经放射治疗,21例呈放疗后状态,其中包括2例液化性坏死,6例凝固性坏死;9例放疗后残存。结论：MR平扫及增强扫描对鼻咽癌、鼻咽癌颅底骨转移、鼻咽癌放疗中、后改变及放疗后复发有较高的诊断、评估价值。     

硬X射线调制望远镜直接解调成像方法快速实现

针对硬X射线巡天望远镜具有的18个探测器的设计,本文给出了直接解调成像方法快速实现的两个途径。一是根据点扩展函数值中有大量零元的事实,给出了基于点扩展函数值的非零元的Lucy迭代计算和存储方法：二是将直接解调成像方法中Lucy迭代改为观测数据按一定方式分组排序的Lucy迭代。数据实验表明,本文方法大幅度提高了直接解调成像的速度。     

螺旋CT三维重建在脑血管疾病诊断中的应用

目的评价螺旋CT三维重建在脑血管疾病诊断中的作用.方法对51例临床脑血管病患者行脑增强CT扫描后三维重建图像进行分析,所有检查采用GE Hispeed NX/I所排CT扫描机,将图像传输至工作站进行三维重建; 图像经2位以上放射科诊断医师阅片分析.结果51例临床脑血管病患者中:脑血管正常14例;单纯变异7例;其他脑血管均有不同程度变窄(30例),其中混合型变窄12例(两支以上含两支脑血管变窄),脑血管变异合并脑血管变窄5例,脑血管单支变窄13例.结论螺旋CT脑增强扫描三维重建是诊断脑血管病变的比较理想且有效的检查方法.     

考虑实际投影成像平面位置的扇束滤波反投影(FFBP)算法

扇束滤波反投影(Fan-beam Filtered Back Projection- FFBP)算法理论公式中,投影成像平面位于旋转中心;而实际CT扫描系统中,投影成像平面与旋转中心都存在一定距离.考虑到实际投影成像平面位置,本文推导了它的FFBP算法(即IFFBP-Improved Fan-beam Filtered Back Projection算法),比较了此两种情况下(即忽略成像平面与旋转中心距离)FFBP、IFFBP算法重建质量.计算机模拟和实验结果证明了IFFBP算法的正确性.     

Localization of water bearing fractured zones in a hard rock area using integrated geophysical techniques in Andhra Pradesh,India

Knowledge of the existence of fracture zones, their extent, intensity and direction is very useful for assessing groundwater in hardrock regions and in this context geophysical methods are widely accepted as a powerful means of study. In the modern era of exploration, application of the Resistivity Imaging technique gives a new opportunity for groundwater study in hardrock regions. Exploration surveys were conducted at one of the important sites in Maheshwaram watershed, Andhra Pradesh, India with a multielectrode resistivity imaging system. To reduce the ambiguity of geophysical interpretation some complementary geophysical studies like ground Magnetic and VLF were also carried out.A number of 2D resistivity images were prepared in a grid pattern, which clearly show the weathered and fractured zones in different parts of the study area. With the help of all 2D profiles a quasi-3D image has been created, which indicates the orientation and extension of the fracture zone in a horizontal as well as vertical direction in the study area. Strong agreement exists among the anomalies identified using the ground magnetic, VLF and resistivity imaging methods. The litholog data available in the study area also helps to interpret geophysical results to find a potential groundwater bearing zone in that area.     

南京市心脑血管疾病的医疗气象预报研究

以2003年1月至2008年7月南京市某医院的心脑血管逐日就诊人数为样本,首先根据其时间分布特征采用虚拟变量选择包含节假日等的22个非气象因子,然后通过逐步回归法筛选气象因子和非气象因子,得到最终模型的解释变量,采用支持向量机(SVM)回归方法分别构建了南京市心、脑血管疾病预测模型。将就诊人数分为5个等级,通过反查,模型针对心、脑血管疾病在同一等级和差一等级的准确率分别为87.91%和84.62%,实际预测结果较好,证明该模型具有较高的实际应用价值。     

The DODO survey – II. A Gemini direct imaging search for substellar and planetary mass companions around nearby equatorial and Northern hemisphere white dwarfs

The aim of the Degenerate Objects around Degenerate Objects (DODO) survey is to search for very low-mass brown dwarfs and extrasolar planets in wide orbits around white dwarfs via direct imaging. The direct detection of such companions would allow the spectroscopic investigation of objects with temperatures much lower  (<500 K)  than the coolest brown dwarfs currently observed. These ultra-low-mass substellar objects would have spectral types >T8.5, and so could belong to the proposed Y dwarf spectral sequence. The detection of a planet around a white dwarf would prove that such objects can survive the final stages of stellar evolution and place constraints on the frequency of planetary systems around their progenitors (with masses between 1.5 and 8   M_⊙  , i.e. early B to mid-F). This paper presents the results of a multi epoch J band common proper motion survey of 23 nearby equatorial and Northern hemisphere white dwarfs. We rule out the presence of any common proper motion companions, with limiting masses determined from the completeness limit of each observation, to 18 white dwarfs. For the remaining five targets, the motion of the white dwarf is not sufficiently separated from the non-moving background objects in each field. These targets require additional observations to conclusively rule out the presence of any common proper motion companions. From our completeness limits, we tentatively suggest that  ≲5 per cent  of white dwarfs have substellar companions with   T _eff≳ 500 K  between projected physical separations of 60–200 au.     

紫山东断裂北段电阻率层析成像与地震勘探的联合探测

通过电阻率层析成像、浅层地震勘探,结合钻孔资料,获得了紫山东断裂北段的形态、活动时代.电阻率层析成像、地震勘探揭露紫山东断裂北段的断层面上端点的埋深大于150m,最新活动到中更新世早期.     

利用FMI资料分析塔河油田南部中—下奥陶统储层构造应力场

钻探结果表明,塔河油田南部地区上奥陶统覆盖区中—下奥陶统碳酸盐岩储层发育与分布明显地受断裂和裂缝控制。裂缝主要为构造开启缝,其次为钻井诱导缝,裂缝走向具有明显方向性,其形成与古构造应力场关系密切。利用大量中—下奥陶统钻井FMI资料进行裂缝识别、成因分类和走向统计分析,认为钻井诱导缝受现今构造应力场控制,构造开启缝主要受古构造应力场控制,裂缝走向与最大主应力方向一致。塔河油田南部地区诱导缝优势走向为北东向,现今最大主应力方向为北东向;构造开启缝优势走向主要有北北东向和北东东向两组,北北东向裂缝中可见充填缝,反映北北东向裂缝形成时间早于北东东向,其分别与加里东中期和海西早期的古构造应力场最大主应力方向相一致。     

How to use the groundwater resources at the area polluted by organoarsenic compounds for Old Japanese Army Toxic Gas Weapon in Japan

从医学地质学角度看,在日本地质污染的地方如何使用地下水资源,我们面临许多问题.本文讨论了地质污染学(geo-pollution science)作为医学地质学中一门学科的概念以及在受二苯亚砷酸污染的地方成功使用农业地下水的案例.