外围性小肺癌的CT诊断

作者报告了４０例外围性小肺癌。并对≤３ｃｍ的外围性小肺癌的ＣＴ征象进行了讨论和总结。作者认为：小结节征、分叶征、棘状突、空泡征、胸膜凹陷等征象，对外围性小肺癌有诊断价值。     

脑囊虫病的CT诊断－附300例分析

作者报告了３００例脑囊虫。对脑囊虫病的ＣＴ表现进行了讨论。作者认为；（１）平扫为多发小囊状低密度灶，如囊壁上有高密度点。（２）较大囊状低密度灶，囊壁上有高密度点。（３）平扫为多发局灶性低密度区，增强出现多发结节及环形强化灶。为诊断脑囊虫病有价值的征象。本文还对脑囊虫病的病理及鉴别诊断进行了讨论。     

用超速CT机检测99例无症状香港中国人降低钙指数

回顾分析Ｍａｔｉｌｄａ医院超速ＣＴ室筛选首批病人中９９例中国人资料，很明显从通常采用１３０－１００Ｈｏｕｎｓｆｉｅｌｄ单位作为检出冠状血管钙化的基数应用至中国人身上其阈值数目需要降低，同时，我们也发现如果病人年龄按每１０年范围分组（２１－３０，３０－４０，４１－５０，５１－６０）而计算其超速ＣＴ的钙化指数会较随机男女一起按平均计算更易区分其差异．进一步分析显示，男性中年时候超速ＣＴ指数已达最高值，而女性则晚１０年方达最高值，因此，为了更易探测冠脉循环内钙化倾向应作出超速ＣＴ检出钙化的指数数目．这些实践经验对动脉粥样硬化过程的预测或预防有实际意义．     

Interpretation of Mauna Loa atmospheric transmission relative to aerosols,using photometric precipitable water amouts

Precipitable water measurements made coincident in time and space with direct broadband solar irradiance measurements are used in conjunction with an atmospheric transmission model to derive a parameter whose major dependence is on total aerosol extinction. Irradiance measurements are used to calculate an atmospheric transmission factor (ATF) that is independent of the instrument calibration and the extraterrestrial solar constant. The dependency of the ATF on precipitable water is determined using LOWTRAN5, an atmospheric transmission model with high spectral resolution. Precipitable water measurements are then used to adjust the measured ATF to correspond to an ATF value obtained for a constant precipitable water amount. The remaining variability in the adjusted ATF is due mostly to aerosol extinction. The technique is applied to a 6-year period (1978–1983) for clear-sky mornings at Mauna Loa, Hawaii (MLO). MLO ATF aerosol residuals are compared with independently measured monochromatic aerosol optical depth. Results show that the ATF aerosol residual is nearly equal to the 500 nm aerosol optical depth prior to the eruption of E1 Chichon, at which time a nonlinear time-dependent relationship between the two quantities is evident. ATF aerosol residuals reflect the spectrally integrated aerosol influence on transmission and, therefore, could indicate better than monochromatic optical depth the radiation balance perturbations due to aerosols. The 6-year precipitable water record for MLO, determined from a dual-channel sunphotometer, has a mean value of 0.3 cm. An annual cycle in precipitable water is evident, as is a 4-month 5-standard-deviation drought from December 1982 through March 1983.     

某些方解石单晶的光学质量评价

本文用光学方法检查了经野外地质工作者挑选过的天然方解石单晶的光学质量。发现部分晶体的光学均匀性很差,晶体中的光散射颗粒很多,不能满足作为光学介质的要求。     

金川露天矿高边坡的反射地震CT探测研究

高边坡的岩体结构和稳定性研究是工程地质研究的一个重要课题。本次探测使用高分辨率数字地震仪和反射地震CT方法,对金川露天矿高边坡的岩体结构进行了深入细致的探测与研究,清楚地揭示了边坡岩体中优势结构面的产状和组合关系,以及边坡表层松动带厚度分布,未发现顺坡软弱岩层。     

Limestone weathering in Eastern Australia. Part 2: Surface micromorphology study

Results from long term microerosion meter (MEM) studies indicate that microenvironments are characterized by different erosion rates. A complementary study, carried out on the same sites, examines the microscale morphology in each environment. Optical and scanning electron microscopy were used to identify a range of features thought to reflect different processes. Under subaerial conditions micromorphology is dominated by biological weathering features owing to the presence of microflora. Sites permanently covered by soil or stream water have only dissolution etch features, though stream sites may exhibit microfractures. Sites with periodic exposure exhibit both dissolution and biological etch features. The natural environment is more accurately reflected by allowing some microflora colonization of MEM sites rather than preventing colonization by artificial means.     

从全波段太阳直射辐射确定大气气溶胶光学厚度 II：实验研究

本文通过比较太阳直射表和太阳光度计探测的大气柱气溶胶光学厚度，分析了从太阳直射表探测的全波段太阳直射光强信息确定大气柱气溶胶光学厚度的误差，并应用北京观象台的太阳直射表观测资料，反演得到了 1990—1993年北京大气柱气溶胶光学厚度，分析了该光学厚度月与年变化规律以及1991年菲律宾皮纳图博火山爆发对北京大气气溶胶含量的影响。本文还提出了关于有效水汽含量的一个经验关系式，用于确定水汽对太阳辐射的吸收率。     

冻土蠕变过程中结构的CT分析

ＣＴ为非破坏的持续检测和定量描述不同实验条件下试样的内部结构提供了可能，本文利用这一手段观测分析了冻土蠕变过程结构的变化情况，认为冻土蠕变过程中所进行的发育微裂隙、颗粒集合体的破坏以及其它结构缺陷的增生与扩展，制约着土结构的强化与弱化作用，控制着蠕变过程的形态特征，同时还给出了ＣＴ值与物密度和含水量之间的定量关系。     

肝脏肺吸虫病的CT诊断

作者认为肺吸虫病发生在肝脏系少见病例，以ＣＴ认识和诊断上有待进一步提高，特别与肝结核、肝脓肿、肝包虫囊肿等鉴别诊断，仍存在一定的困难。临床上肺吸虫病多见脑部，肺，及皮下组织，我院病理科近十余年在肝脏发现肺吸虫病也是仅有一例，上述疾病ＣＴ表现均可出现低密度坏死区，有规则环状增强，斑点状钙化灶，单房及改变及大小不等的结节。组织学上的改变，肝细胞混浊肿胀，液化，变性，坏死，钙化，所不同处寄生虫病的病理组