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991.
Serum alpha-feto protein (AFP) and gamma-glutamyl transpeptidase isoenzyme II (gamma-GTP-II) were assayed in 104 patients with primary hepatic carcinoma (PHC), gamma-GTP-II had a higher specificity of 95.7%, while AFP a higher sensitivity of 84.6%. There was no significant difference in the positive diagnostic rate of the two markers in patients with AFP > or = 400 micrograms/L and with AFP < 400 micrograms/L. Nor was there any difference if the patients were divided into four groups according to the serum AFP levels of 200 micrograms/L, 400 micrograms/L and 1,000 micrograms/L. Altogether 97 of the 104 PHC patients were detected when the two markers were assayed in combination (40 out of 42 PHC patients with AFP > or = 400 micrograms/L and 57 out of 62 PHC patients with AFP < 400 micrograms/L). These results suggest that combined assay of the two serum PHC markers will increase the detecting rate of PHC and be of value especially in those patients with normal or low serum level of AFP. 相似文献
992.
河流相储层平面连续性精细描述 总被引:52,自引:2,他引:50
河流相储层在大庆油田的产油层中占有重要比例,河流相储层的平面连续性是影响其非均质性的主要方面,是油藏精细描述和建模的基础和关键.近年来,众多研究者采用露头调查类比的方法进行油田地下储层的精细描述和建模工作,但受限于沉积环境、沉积条件的不确定性,该方法具有一定的局限性.文中利用深度开发阶段老油田密井网提供的丰富的动、静态资料,将沉积过程分析、界面分析、测井曲线分析及油田动态资料分析相结合的思路应用于油田地下研究,进行河流相储层平面连续性精细描述,重点探讨了储层细分微相、单一河道砂体的识别及砂体之间的连通性等内容.研究成果对老油田储层建模及剩余油分布的地质研究工作具有借鉴意义. 相似文献
993.
本文提出了一种实现合成孔径雷达(SAR)成像处理的并行距离/多普勒算法,该算法能有效地提高SAR的成像处理速度,是实现SAR实时成像处理的有效途径,该算法尤其适合于超级并行机(MPP)及工作站和微机构成的群机系统进行并行计算。实验结果表明该并行算法能有效地减少SAR成像处理的运算时间。最后给出了原始数据的成像结果。 相似文献
994.
PLC在多机通讯方面的应用 总被引:1,自引:0,他引:1
本文介绍以平网印花机为工程背景的基于485-BD通讯接口的PLC多机通讯方案,提出了解决通讯信号冲突的方法,设计了通讯命令以及状态处理方面的方案。该系统在实际运行中完全达到设计要求。 相似文献
995.
Kong Jin Au Lin Sching L. Chuang Shun Lien 《Geoscience and Remote Sensing, IEEE Transactions on》1984,(4):377-382
The emissivity of a periodic surface is calculated from one minus the reflectivity by using the reciprocity principle. The reflectivity consists of the sum of all scattered power as determined from the modal theory which obeys both the principle of reciprocity and the principle of energy conservation. The theoretical results are matched to experimental data obtained from brightness temperature measurements as functions of viewing angle for soil moisture in plowed fields. The threshold phenomenon with regard to the appearing and disappearing of modes in their contributions to the scattered field amplitudes is discussed in connection with the theoretical results. It is shown that this approach for calculating the emissivity greatly reduces computational efforts by requiring substantially smaller matrix sizes. 相似文献
996.
GIS内部放电监测方法的分析 总被引:1,自引:0,他引:1
本文对GIS内部放电监测方法进行比较分析,并通过对不同的内部放电形式下,测量灵敏程度的分析,提出监测方法的综合将是准确判别放电程度的发展方向。 相似文献
997.
P. K. Chaviaropoulos N. N. Soerensen M. O. L. Hansen I. G. Nikolaou K. A. Aggelis J. Johansen Mac Gaunaa T. Hambraus Heiko Frhr. von Geyr Ch. Hirsch Kang Shun S. G. Voutsinas G. Tzabiras Y. Perivolaris S. Z. Dyrmose 《风能》2003,6(4):387-403
The recent introduction of ever larger wind turbines poses new challenges with regard to understanding the mechanisms of unsteady flow–structure interaction. An important aspect of the problem is the aeroelastic stability of the wind turbine blades, especially in the case of combined flap/lead–lag vibrations in the stall regime. Given the limited experimental information available in this field, the use of CFD techniques and state‐of‐the‐art viscous flow solvers provides an invaluable alternative towards the identification of the underlying physics and the development and validation of sound engineering‐type aeroelastic models. Navier–Stokes‐based aeroelastic stability analysis of individual blade sections subjected to combined pitch/flap or flap/lead–lag motion has been attempted by the present consortium in the framework of the concluded VISCEL JOR3‐CT98‐0208 Joule III project. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
998.
999.
Utilizing wind and solar energy as power sources for a hybrid building ventilation device 总被引:1,自引:0,他引:1
Wind and solar energy are currently used to power many building ventilation devices. Such devices rely exclusively on either solar or wind energy, which limits their usefulness. A low-cost hybrid ventilation device that utilizes both wind and solar energy as power sources was designed to overcome some of the shortcomings of these devices. Wind tunnel testing conducted at the aerodynamics laboratory of the University of New South Wales revealed that the hybrid device had improved operational and performance benefits compared with conventional commercial roof top ventilators, particularly at zero to low wind speeds. This represents a significant step forward and will have an immediate impact in promoting the use of clean energy for the purposes of building ventilation. 相似文献