HRCT及螺旋CT增强扫描在周围型小肺癌诊断中的价值   总被引：1，自引：0，他引：1  

徐春林  刘伟  王建国  彭磊  张雪梅  康苏平 《CT理论与应用研究》2003,12(3):26-30

目的:探讨HRCT及螺旋CT增强扫描在周围型小肺癌诊断中的价值。方法:搜集经手术或穿刺病理证实的周围型小肺癌(直径≤3cm)46例,全部行HRCT扫描,分析其各种CT征象。25例行螺旋CT增强扫描,对病灶强化前后CT值增幅特点进行分析。结果:HRCT表现:①分叶征(91.3%);②毛刺征(87%);③胸膜凹陷征(78.3%);④血管集束征(54.3%);⑤空气支气管征及空泡征(34.8%);⑥棘状突起(32.6%);⑦磨玻璃样密度(10.9%);⑧钙化(8.7%)。强化前后CT值增幅20~30HU占16%,30~65HU占76%,>65HU占8%。结论 :HRCT及螺旋CT增强扫描是周围型小肺癌诊断中重要的检查手段。同时具备3个及其以上CT征象,尤其是前5个征象中2个以上即可确诊,其正确率为91.3%。强化前后CT值增幅在20~65HU之间,对于肺癌诊断更加可靠,正确率达92%。  相似文献   

An investigation on dewatering kinetics of ultrafine coal     

D. Tao  B. K. Parekh  J. T. Liu  S. Chen 《International Journal of Mineral Processing》2003,70(1-4):235-249

Ultrafine coal dewatering is of great importance to the coal industry due to its impacts on the handling and utilization characteristics of coal products. Commercially available filtration techniques are either ineffective or costly for dewatering of ultrafine coal to the desired moisture level of about 20%. Considerable efforts have been devoted to understanding the dewatering process and developing new technologies for applications in the coal industry. Most of the previous work on ultrafine coal filtration was focused on the final filter cake moisture and few studies have been conducted to investigate the filtration kinetics. The present investigation was undertaken to better understand the kinetics of vacuum filtration of ultrafine coal under various conditions. The filtrate weight was continuously monitored using a precise load cell during the entire filtration process. Operating parameters such as vacuum pressure and reagent conditioning time were examined for their impacts on filtration kinetics. Use of cationic and anionic flocculants showed significant improvement in filtration kinetics. Kinetic data obtained from the study were used to determine the fundamental parameters of filtration such as cake permeability, specific cake resistance, and filter medium resistance using the integrated form of the Darcy's law.  相似文献   

桂北前寒武纪浅变质细碎屑岩型锑矿地质特征及成因     

王瑞湖 《矿产与地质》2002,16(4):212-216

桂北隆起区锑矿主要为产于前寒武纪浅变质细碎屑岩中的碎裂岩—石英脉型锑矿床 ,其成因与地下热水渗滤作用有关。其矿源来自于上地壳围岩 ,水源以大气降水为主、部分混染有变质水 ,硫源较复杂、具混合硫特征 ,热源由隐伏岩体、放射性元素和断裂磨擦提供。成矿流体为富含 CO2的 Na - K - Ca2 - SO42 -- Cl-型水溶液 ,成矿温度以 2 1 0～ 2 4 0℃为主 ,压力 1 0～ 38MPa,成矿时代为燕山期  相似文献   

用PB绘制建筑物安全监测过程线     

黄万里  石辛喜  王天祥 《北京测绘》2002,(2):38-41

本文介绍了在PB开发的安全监测系统中绘制过程线的方法，该方法用Windows API函数绘制矢量格式的过程线，用该方法绘制的过程线具有占用磁盘空间小、管理方便的特点，大大提高了安全监测系统的性能、使监测资料管理更方便。  相似文献   

环形强化征在增强CT扫描诊断肺结核瘤中的价值     

郭艺华 《CT理论与应用研究》2002,11(2):42-44

目的评价CT增强扫描环形强化征对肺结核瘤的诊断价值。方法 病理或临床证实的肺结核瘤21例，肺癌13例，炎性假瘤8例，均行CT平扫加增强扫描，分析病灶强化程度及强化形态。上述病例中肺结核瘤8例，肺癌13例，炎性假瘤4例经手术治疗，切除标本病理检查，分析标本血管数目与分布，将病灶CT扫描强化程度及强化形态与病灶内血管数目和分布作对照分析。结果 环形强化征仅见于肺结核瘤，结核瘤中央干酪性坏死，周边纤维包膜下含有血管结构丰富的肉芽组织是环形强化的病理基础。结论 环形强化征是肺结核瘤CT增强的形态特征，对结核瘤的论断具有肯定价值。  相似文献   

Size fractionation and optical properties of colloids in an organic-rich estuary (Thurso, UK)   总被引：2，自引：0，他引：2  

Silvia Batchelli  Franois L.L. Muller  Mohamed Baalousha  Jamie R. Lead 《Marine Chemistry》2009,113(3-4):227-237

The optical characteristics of a black water river estuary from the north coast of Scotland were examined in the filtered (0.4 µm), ultrafiltered (5 kDa) and colloid-enriched fractions of estuarine samples. The samples were collected over the full salinity range during a period when the pH was relatively constant (8.2–8.5) throughout the estuary, allowing the influence of salinity on estuarine colloidal processes to be distinguished. The properties examined in the bulk, the low molecular weight (LMW) and the colloidal fraction (HMW) were UV–visible absorption, 3-D fluorescence excitation–emission matrix (EEM) spectrum, inorganic and organic carbon, mean size (by dynamic light scattering), and size distribution by flow field-flow fractionation analysis (FlFFF). The combined results of these analyses support the view that river-borne, humic-rich colloids underwent two types of transformation upon mixing with the seawater end member. The first one resulted in an apparent increase in the abundance of LMW constituents and may be explained by coiling of the individual humic macromolecules. The second one resulted in an increase in the mean size measured in both the lower and higher colloidal size ranges, and may be explained by aggregation of colloids to form entities that were still mostly colloidal i.e., smaller than 0.4 µm. The LMW contribution to the bulk optical properties increased with increasing salinity. Very similar findings were obtained from simulated mixing experiments using a Nordic Reference NOM extract as a source of freshwater colloids. This indicates that changes in the molecular architecture and molar mass of river-borne colloids—not changes in their chemical nature—were responsible for the observed variations in the spectral characteristics of CDOM in this estuary.  相似文献   

An Innovative Process to Improve Turbidity and Organics Removal by BAC Filters     

MIAO Jia ZHAO Qingliang WANG Baozhen LI Ji ZHANG Jinsong 《中国海洋大学学报(英文版)》2006,5(4):387-392

The turbidity criterion for the product water of a WTP according to the State Project ‘863＇ on the safeguard technology of drinking water in the southern areas of China is 0.1 NTU. The turbidity removal in the activated carbon filter was analyzed in a pilot-scale test and an innovative technology to improve the turbidity removal in a biologically activated carbon （BAC） filter was put forward in order to meet the criterion. Experimental results showed that the enhanced filtration by adding polymerized aluminium chloride （PAC） into the BAC filter was quite effective in turbidity control. The effluent turbidity was kept at a stable level （mean） of 0.033 NTU with a high removal of about 80% for influent turbidity of 0.110- 0240 NTU with an addition of PAC at 0.05 mg L^-1, meeting the requirement for filtrate turbidity equal to or less than 0.1NTUC totally. In addition, the larger the PAC dosage was, the lower the effluent turbidity was. However, further improvement of turbidity removal was not obvious for PAC dosages beyond 0.10 mg L^- 1, and an optimal PAC dosage in the range of 0.05 - 0.10 mg L^- 1 was proposed.  相似文献   

Lognormality in the observed size distribution of oil and gas pools as a consequence of sampling bias     

M. Power 《Mathematical Geology》1992,24(8):929-945

Economic filtration has been offered as an explanation of the observed lognormality in the size distribution of discovered oil and gas deposits. The result leads to the conclusion that one cannot impute the shape of the underlying parent distribution from the observed discoveries size distribution. The fact that the largest pools tend to be discovered early in the exploration history of an area of interest suggests the existence of an inherent sampling bias in the discovery process. The bias is influenced by the levels of geologic knowledge and technological sophistication. Furthermore, the existence of the bias leads to lognormality in the observed discoveries size distribution of oil and gas pools. A discovery process model explicitly incorporating the notion of sampling bias was applied to a series of Weibull parent frequency size distributions. The selected parent distributions are of a class suggested in the literature as more reflective of nature's size distribution and have empirical support. The distribution of discoveries resulting from the application of the model to the chosen parent size distributions were tested for lognormality using a chi-squared test. Lognormality was found to be an acceptable model of the discoveries size distribution over a wide range of resource exhaustion measures. When combined with the notion of economic filtration, sampling bias leads to the conclusion that one should not expect the lognormal distribution to accurately represent the underlying parent size distribution of oil and gas deposits.  相似文献   

Climatic forcing before,during, and after the 8.2 Kyr B.P. global cooling event     

Devendra Lal  William G. Large  Stephan G. Walker 《Journal of Earth System Science》2007,116(3):171-177

This paper attempts at full characterization of the unique global 8.2 Kyr B.P. cooling event. Significant atmospheric cooling started during 9.5–8.5 Kyr B.P. when the Sun was extremely quiet during three periods of ∼ 50–100 years. The flood of melt water in the N. Atlantic from glacial lakes during the demise of the Laurentide ice sheet, starting at ∼ 8.5 Kyr B.P., adds to the atmospheric cooling. Climatic forcing events occurred at 8.5 Kyr B.P., at 8.2 Kyr B.P. and finally at 8.06 Kyr B.P., leading to concurrent increases or decreases in the atmospheric Δ¹⁴C levels, completely consistent with the climatic forcing proposed here.  相似文献   

膜过滤在污水处理中的应用研究进展   总被引：3，自引：0，他引：3  

徐新阳  马铮铮 《气象与环境学报》2007,23(4):52-56

膜滤是借助一定的外加压力使液体穿过膜后分离成浓缩液和渗透液的分离技术。常用于水处理的膜滤依据过滤膜孔径、被截留物质的尺寸和施加的过滤压力不同可分为微滤、超滤、纳滤和反渗透等。介绍了不同膜滤技术的渗透原理、膜的类型、过滤模型以及膜的污染与防治,概述了膜过滤在处理垃圾填埋场渗沥液和处理纺织印染工业废水以及中水回用等领域的应用,并探讨了膜滤技术今后的研究方向。  相似文献