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Le Ji Xiaoqian Dang Binshang Lan Qichun Song Dapeng Duan Zhe Ji Yongtao Zhang Lisong Heng 《科学通报(英文版)》2014,59(32):4298-4303
The weight-drop impact is widely used in making animal model of spinal cord injury (SCI). But there has not yet been an appropriate unit for the quantification of the impact. In this study, we compared the degrees of the spinal cord injury caused by weight-drop impact with the same momentum but different combinations of drop weight and drop height, in order to test whether "momentum" is capable of being the unit for the quantification of weight- drop impact. Thirty adult rats were randomly allocated to three groups and were injured with 5 g-10 cm (group A), 10g-2.5 cm (group B) and 15 g-l.ll cm (group C) impacts with the same momentum to the spinal cord, respectively. Open-field locomotor function was evaluated using the Basso-Beattie-Bresnahan (BBB) locomotor rat- ing scale. The percentage of spared tissue area (STA) at the epicenter, and 500, 1000 and 1500 gm from the epicenter was calculated using serial sections stained by hematoxylin and eosin. As a result, the behavioral recovery (BBB scores) and the STA percentage were similar in group B and group C. However, the BBB score in group A was significantly lower than that in groups B and C at the same time point post injury. The STA percentage was signifi- cantly less and the lesion/cavity length was significantlygreater in group A than in groups B and C. These suggested that the 5 g-10 cm weight-drop impact, compared with the other two impacts with different weights and heights, caused a greater damage of the spinal cord when the momentum was the same. So, these impacts with the same momentum but different weights and drop heights cause different degrees of spinal cord injury. Momentum alone is inadequate to be the unit for the qualification of weight- drop impact and to be used to predict the extent of injury. 相似文献
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随着半导体及电子工艺技术的迅速发展,器件向着小尺度、低电压、低电荷、高集成度迈进,大气中子对航空及地面的电子系统造成的单粒子效应越来越显著.本文采用PHITS2.24蒙特卡罗程序及其事件发生器功能,借助于核反应模型与截面数据,验算了描述器件发生单粒子翻转能力的MBGR参数,并采用大气高能中子能谱,对SRAM器件的单粒子翻转率进行了计算与分析.这为我们今后模拟大气中子产生的各类单粒子效应提供了基本方法,也为将来开展相应的辐照实验提供了理论基础. 相似文献
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针对镍线电阻对焊接头出现的质量问题,进行了系统的对焊工艺试验,结合拉伸试验和金相断口的观察检验,提出了合理的焊接工艺范围和防止工艺缺陷的措施,解决了镍线对焊的接头质量问题. 相似文献
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运用现代控制理论中的系统辨识方法而给出了多层递阶法的伤亡事故预测系统的动态模型、基本原理,提出运用多层递阶方法对伤亡事故进行预测,通过对某飞机制造公司伤亡事故的实例分析表明,与固定参数预测模型相比较,基于多层递阶的预测过程可以充分利用长时间统计数据,并能减小预测误差,提高预测精度。 相似文献
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