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流体运动场中的力学问题及其解法 被引量:1
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作者 段毅文 张馨颖 《内蒙古石油化工》 CAS 2014年第23期35-36,共2页
自然过程或过程工业中,遇到的大部分物料(包括:媒体介质或原料、中间产品和产品)均为流体聚集态(包括:气体、液体或超临界流体);这些物质都是由分子组成的,且在任意两分子之间总保持一定的距离,即:分子所占据的空间是不连续的;现有许多... 自然过程或过程工业中,遇到的大部分物料(包括:媒体介质或原料、中间产品和产品)均为流体聚集态(包括:气体、液体或超临界流体);这些物质都是由分子组成的,且在任意两分子之间总保持一定的距离,即:分子所占据的空间是不连续的;现有许多研究者正力图采用离散模型(分子动力学、蒙特卡罗法和量子力学)解决工程中所遇到的问题[1];但若在1mm3工程特征尺寸中含有1010以上个分子(满足统计规律)时,流体场中的物理变化、化学变化、生化变化和社会变化就会呈现出连续性,这时人们就可以运用几百年来延用的连续模型处理流体问题。本文将采用连续模型探讨流体运动场中的力学问题。 展开更多
关键词 势函数 流函数 N-S方程 边界层 分子微观运动 体系宏观性质
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Histopathological Analysis of Liver During Pregnancy Toxemia in Small-tailed Han Sheep
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作者 Mingcheng WANG Enzhong LI Gailing WANG 《Agricultural Science & Technology》 CAS 2014年第3期470-473,共4页
The present work aimed to investigate the microscopic and ultramicro- scopic structure of the liver to assess the level of hepatic impairment during preg- nancy toxemia. Seven pregnant small-tailed Han sheep of negati... The present work aimed to investigate the microscopic and ultramicro- scopic structure of the liver to assess the level of hepatic impairment during preg- nancy toxemia. Seven pregnant small-tailed Han sheep of negative urine ketone bodies were assessed in this study. Toxemia was induced by limiting food and movement tate in pregnancy. Three sheep developed obvious clinical symptoms with motor weakness, depression, anorexia, locomotion disturbances, blindness and lan- guishment. We harvested their liver tissues as pathological material, and used rou- tine histological and electronic microscopy methods to observe the histopathological changes in small-tailed Han sheep induced by pregnancy toxemia. Autopsy of the livers of the sheep revealed deep yellow coloration, intumescence and hemorrhage on the surface. Microstructural features indicated fatty degeneration, which is a main characteristic of fatty liver. Hepatocellular ultrastructural changes were observed un- der an electronic microscope. The characteristic findings were nucieolus concentra- tion, vacuolation of mitochondria and excessive glycogen granules in the cytoplasm. Via this experimental protocol, pregnancy toxemia of sheep was successfully in- duced, providing a pathological model for the study of this disease. After the experi- mental induction of pregnancy toxemia, the clinical symptoms of pathogenic sheep and pathological changes to their livers exhibited obvious characteristics of pregnan- cy toxemia. 展开更多
关键词 Pregnancy toxemia Liver Histopathology Small-tailed Hart sheep
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