空洞性肺结核的CT诊断

目的：分析空洞性肺结核的ＣＴ表现和特征,探讨ＣＴ诊断该病的可靠性。材料与方法：２１例空洞性肺结构病人均做胸部ＣＴ和胸片检查,分析ＣＴ所见并与病理、胸片对照,１０例经组织病理学证实。１１例痰检和临床证实。结果：（１）肺上叶尖后段及下叶背段为空洞性肺结核的好发部位;（２）空洞呈圆形或椭圆形,空洞外壁较光整,空洞壁常有钙化;（３）空洞所属支气管壁不规则增厚;（４）临近空洞胸膜局限性增厚;（５）空洞以外肺     

Effects of Faraday rotation observed in filter magnetograph data

In this paper we analyze the effects of Faraday rotation on the azimuth of a transverse magnetic field as determined from the linear polarization in the inverse Zeeman effect. Observations of a simple sunspot were obtained with the Marshall Space Flight Center's vector magnetograph over the wavelength interval of 170 mÅ redward of line center of the Fe i 5250.22 Å spectral line to 170 mÅ to the blue, in steps of 10 mÅ. These data were analyzed to produce the variation of the azimuth as a function of wavelength at each pixel over the field of view of the sunspot. At selected locations in the sunspot, curves of the observed variation of azimuth with wavelength were compared with model calculations for the azimuth at each wavelength as derived from the inverse Zeeman effect modified by Faraday rotation. From these comparisons we derived the maximum amount of rotation as functions of both the magnitude and inclination of the sunspot's field. These results show that Faraday rotation of the azimuth will be a significant problem in observations taken near the center of a spectral line for fields as low as 1200 G and inclinations of the field in the range 20–80 deg. Conversely, they show that measurements taken in the wing of a spectral line are relatively free of the effects of Faraday rotation.     

Copper(II) humate mobility in kaolinite soil

An investigation of the influence of humate on the mobility of copper(II) ions in a kaolinite soil using leaching tests and electrokinetic experiments is reported. The data are interpreted in terms of humate–copper–clay interactions and humate electrical charge. Humate is mostly immobile below pH8 but is more mobile in alkaline conditions (sorption to kaolinite reduces its mobility in neutral conditions). Copper humate complexes are mobile in both acidic and alkaline conditions, but not in neutral conditions where they are sorbed. The dissolved copper humate complexes that form in acidic conditions are positively charged. The net effect of humate is to increase cupric ion mobility in kaolinite soil, especially in alkaline conditions.     

一种新的地图数据检索方法及其应用软件

本文提出了一种新的实用地图数据检索方法——“放大镜”式地图数据检索,建立了相应的软件系统,并讨论了该方法的数学基础、软件的特点,还给出了应用实例。     

中国夏季气候对植被覆盖的影响:1982～2001(英文)

In this paper, we apply lagged correlation analysis to study the effects of vegetation cover on the summer climate in different zones of China, using NOAA/AVHRR normalized difference vegetation index (NDVI) data during the time period from 1982 to 2001 and climate data of 365 meteorological stations across China (precipitation from 1982 to 2001 and temperature from 1982 to 1998). The results show that there are positive correlations between spring NDVI and summer climate (temperature and precipitation) in m...     

Exploring the sensitivity of coastal inundation modelling to DEM vertical error

As sea level is projected to rise throughout the twenty-first century due to climate change, there is a need to ensure that sea level rise (SLR) models accurately and defensibly represent future flood inundation levels to allow for effective coastal zone management. Digital elevation models (DEMs) are integral to SLR modelling, but are subject to error, including in their vertical resolution. Error in DEMs leads to uncertainty in the output of SLR inundation models, which if not considered, may result in poor coastal management decisions. However, DEM error is not usually described in detail by DEM suppliers; commonly only the RMSE is reported. This research explores the impact of stated vertical error in delineating zones of inundation in two locations along the Devon, United Kingdom, coastline (Exe and Otter Estuaries). We explore the consequences of needing to make assumptions about the distribution of error in the absence of detailed error data using a 1 m, publically available composite DEM with a maximum RMSE of 0.15 m, typical of recent LiDAR-derived DEMs. We compare uncertainty using two methods (i) the NOAA inundation uncertainty mapping method which assumes a normal distribution of error and (ii) a hydrologically correct bathtub method where the DEM is uniformly perturbed between the upper and lower bounds of a 95% linear error in 500 Monte Carlo Simulations (HBM+MCS). The NOAA method produced a broader zone of uncertainty (an increase of 134.9% on the HBM+MCS method), which is particularly evident in the flatter topography of the upper estuaries. The HBM+MCS method generates a narrower band of uncertainty for these flatter areas, but very similar extents where shorelines are steeper. The differences in inundation extents produced by the methods relate to a number of underpinning assumptions, and particularly, how the stated RMSE is interpreted and used to represent error in a practical sense. Unlike the NOAA method, the HBM+MCS model is computationally intensive, depending on the areas under consideration and the number of iterations. We therefore used the HBM+ MCS method to derive a regression relationship between elevation and inundation probability for the Exe Estuary. We then apply this to the adjacent Otter Estuary and show that it can defensibly reproduce zones of inundation uncertainty, avoiding the computationally intensive step of the HBM+MCS. The equation-derived zone of uncertainty was 112.1% larger than the HBM+MCS method, compared to the NOAA method which produced an uncertain area 423.9% larger. Each approach has advantages and disadvantages and requires value judgements to be made. Their use underscores the need for transparency in assumptions and communications of outputs. We urge DEM publishers to move beyond provision of a generalised RMSE and provide more detailed estimates of spatial error and complete metadata, including locations of ground control points and associated land cover.     

Late Pleistocene deposits at Block Fen,Cambridgeshire, England

Organic sediments in a gravel quarry at Block Fen, Cambridgeshire, form a sheet dividing lower from upper gravels. Analyses of pollen, macroscopic plant remains and molluscs from these organic sediments are presented. They indicate the presence of temperate freshwater and slightly brackish fine floodplain sediments, which, on the basis of the palaeobotany, are correlated with the temperate Ipswichian Stage. The freshwater sediments, ascribed to Ipswichian substage IIb, occur at ca. ?3 m OD. Marine-influenced tidal sediments, ascribed to Ipswichian substage III, occur at ca. ?6 m OD. No evidence was found for the presence of more than one temperate stage in the sequence. The lower gravels are then correlated with the cold Wolstonian Stage and the upper gravels with the cold Devensian Stage. In contrast to the woodland environments indicated by the palaeobotany of the Ipswichian organic sediments, post-Ipswichian pollen diagrams and macroscopic plant remains in the upper suite of sands and gravels indicate open tree-less vegetation typical of the cold Devensian Stage. They also contain a typical cold-stage mollusc fauna. The sediments containing these floras and faunas are associated with thermal contraction cracks, indicating the presence of permafrost. The final sand and gravel aggradation in the Devensian forms the Block Fen Terrace, near 0 m OD. The evidence indicates that it is younger than the lacustrine sediments resulting from the blocking of the Fenland at the Wash by Late Devensian ice at ca. 18.5 ka BP. The sequence at Block Fen is related to nearby Ipswichian and Devensian sediments at Chatteris, March, Wimblington and Mepal, and to deposits at Wretton on the east margin of Fenland. The correlation permits an outline reconstruction of the history of the valley carrying the River Great Ouse between the Isle of Ely and the Chatteris and March ‘islands’ from the time of a gravel aggradation before the Ipswichian to the Flandrian. The reconstruction shows the time and level of the Ipswichian marine incursion into the Middle Level of Fenland and the extent of aggradation and erosion in the Devensian.     

Correction for water depth variations of marine crustal reflection seismic data using refraction statics

Water depth variations in marine reflection seismic profiling cause velocity push-down and, in regions of rapid fluctuations of the water-bottom slope, stack degradation. Static corrections are a very satisfactory and practical solution to these problems under typical survey conditions with water depths not exceeding a few hundred metres and relatively hard water bottoms. Static time shifts are best derived from a refraction analysis of first arrivals rather than from fathometer data, especially over underwater valleys where unconsolidated sediment of velocity close to that of water has been deposited unconformably onto the underlying lithified rocks. These points are illustrated by a field example from the GLIMPCE survey in Lake Superior. The availability of computer-effective algorithms such as the generalized linear inversion method allows the implementation of refraction statics during the initial processing of regional marine crustal surveys.LITHOPROBE Publication No. 263.