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2008 2

2000 1

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不利荷载 1

对比分析 1

工作性态 1

连拱坝 1

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Particle-scale simulation of fluidized bed with immersed tubes

ZHAO Yongzhi, JIANG Maoqiang, CHENG Yi

《化学科学与工程前沿（英文）》 2008年第2卷第3期页码 341-345 doi: 10.1007/s11705-008-0046-8

摘要： In order to simulate gas-solids flows with complex geometry, the boundary element method was incorporated into the implementation of a combined model of computational fluid dynamics and discrete element method. The resulting method was employed to simulate hydrodynamics in a fluidized bed with immersed tubes. The transient simulation results showed particle and bubble dynamics. The bubble coalescence and break-up behavior when passing the immersed tubes was successfully predicted. The gas-solid flow pattern in the fluidized bed is changed greatly because of the immersed tubes. As particles and gas are come in contact with the immersed tubes, the gas bubbles will be deformed. The collisions between particles and tubes will make the tubes surrounded by air pockets most of the time and this is unfavorable for the heat transfer between particles and tubes.

关键词： unfavorable computational gas-solid particle discrete

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连拱坝的工作性态研究

顾冲时,李雪红

《中国工程科学》 2000年第2卷第10期页码 93-97

摘要：

连拱坝由于结构单薄，对周围环境变化影响比较敏感。文章结合梅山、佛子岭两座连拱坝的实测资料，采用多种模型和分析方法，对其工作性态进行了对比分析，由此引出连拱坝变形、稳定、强度和裂缝等的不利荷载工况。

关键词：连拱坝工作性态不利荷载对比分析

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Effects of hypoxia on mRNA expression of housekeeping genes in rat brain tissue and primary cultured neural cells

YANG Yingzhong, MA Lan, GE Rili, FAN Wenhong, ZHU Lingling, ZHAO Tong, WU Yan, FAN Ming

《医学前沿（英文）》 2008年第2卷第3期页码 239-243 doi: 10.1007/s11684-008-0045-7

摘要： Internal standards are critical for quantitative RNA analyses. Housekeeping genes are often used as internal standards with the assumption that their expression levels remain relatively constant in different experimental conditions. In this study, four commonly used housekeeping genes, Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), ?-actin, 28S rRNA and 18S rRNA were selected to test whether this assumption is tenable under hypoxic conditions. We tested the RNA expression level of these four genes in different hypoxic conditions. Rats subjected to acute hypoxia for 2 hours were used for tissue detection. Primary cultured neural stem cells from E13 fetal rats were treated with 3% O or 10% O for 24 hours for experiments. In both experiments, expression levels of 28S rRNA and 18S rRNA were constant, independent of hypoxia types. However, expression levels of GAPDH and ?-actin were all changed in all kinds of hypoxic conditions. In particular, the mRNA expression level of GAPDH was increased by 43.4% under 3% O hypoxic conditions. These results suggest that 18S rRNA and 28S rRNA are reliable internal controls for comparative analyses of transcription under hypoxia. GAPDH appears particularly unfavorable for this purpose in hypoxic conditions.

关键词： Glyceraldehyde-3-phosphate dehydrogenase comparative constant unfavorable independent