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331.
煤炭作为一种主要的能源在我国的能源需求中一直处于绝对地位.保证煤炭这一重要能源的供应,对我国的经济发展和社会稳定,具有重要的战略意义.本文通过对煤炭运输竞争力影响因素的分析,建立了一套完整科学的煤炭运输竞争力评价指标体系,剖析了各个指标的组成因素.并应用层次分析法,对港口企业煤炭运输竞争力进行了实证评估. 相似文献
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目的 探讨亚低温对脑外伤后细胞凋亡的影响和可能机制。方法 自由落体法制作大鼠脑外伤模型 ,TUNEL法检测细胞凋亡分布及程度 ,免疫组化法检测Bcl 2和Bax蛋白的表达。结果 细胞凋亡率及Bax蛋白表达率均以对照组最高 ,亚低温治疗组次之 ,而Bcl 2蛋白的表达以假手术组最高 ,亚低温治疗组次之 ,对照组最低。结论 亚低温(33± 0 .5 )℃对脑外伤后细胞凋亡虽具有减弱作用 ,但尚未能达到完全抑制的程度。亚低温对Bcl 2和Bax蛋白表达的影响可能是亚低温减弱脑外伤后细胞凋亡的机制之一 相似文献
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Objective On the basis of developing a new animal model for oxyhemoglobin (OxyHb) injection into subarachnoid space in mice, this research was to explore the temporal dependence and spatial distribution of OxyHb- induced apoptosis in the mouse brain cells in vivo and the mechanism of neurocyte injury induced by OxyHb. Methods The animal model for OxyHb injection into subarachnoid space in mice was developed. Mice were divided randomly into the experimental group (n=40) and the control group (n= 35). The control group received saline injection (50 μL ) and the experimental group received OxyHb injection (50 μL ), both into the subarachnoid space. The mice of the two groups were subdivided according to different postoperative time (3 h, 6 h, 12 h, 24 h and 48 h). The apoptosis or necrosis of cells was distinguished with microscopy (HE staining), transmission electron microscopy and TUNEL method. Results The distribution of apoptosis was mainly in the ipsilateral neocortex and bilateral hippocampal gyrus. The apoptotic mouse brain cells showed morphological changes in the experimental group by HE staining and transmission electron microscopy. The count of TUNEL-positive cells showed substantial increase in the experimental group, and there was a significant difference between the control and experimental groups, and the number of OxyHb- induced apoptotic cells decreased with time. Conclusion OxyHb in subarachnoid space in mice can induce apoptasis, but not necrosis of mouse brain cells in viro. The apoptotic brain cells show the pattern of temporal dependence and spatial distribution. It is suggested that the early treatment should be the method of first choice for treating the hemorrhagic brain injury. 相似文献
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针对船舶电力推进系统方案论证效率低、成本高等问题,开发了一款组态式船舶电力推进系统仿真软件。对船舶电力推进系统进行结构划分,并建立了系统的数学模型和仿真模型,并封装形成模型库。使用Matlab/GUI开发界面层,用M语言对Simulink模型进行调用与控制。使用SQL Server 2008创建数据库,实现数据的存取和管理功能。基于该软件对某船舶电力推进系统设计方案进行组态式的图形化建模,并设计了典型工况的仿真实验。结果表明,仿真模型较好预报了实船运行工况。由此可见,该软件可有效验证船舶电力推进系统设计方案。 相似文献
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The interior of superyachts is either designed by an expert or modeled on previous layouts that have been successfully designed. Changing one arrangement to the other is challenging and has not been tried without the buyer’s request, mostly dissuaded by the current manual design procedure. In this work, an approach to determine the interior space arrangement is introduced. Space arrangement is performed by considering various design constraints that are expressed in terms of numerical values such as space occupation, shapes of spaces, and distance of stairs connecting relevant spaces, and a combination of those. The genetic algorithm is adopted to yield the space arrangement formulated as an optimization problem containing multiple objectives. The solution to the space arrangement problem has proven that the designer is able to generate a specific result due to the degree of freedom allowed by the formulation. The proposed design approach has led to efficient layouts for general arrangement of mid-sized superyachts. These possible candidates help the designer to choose a right arrangement based on his or her design concept or intention, which will make the interior arrangement task much easier and faster. 相似文献
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制作了AC-5,AC-10,AC-13型聚氨酯混合料并与同级配沥青混合料进行力学性能、高温稳定性、水稳定性和抗剥落性能等路用性能的研究对比。试验结果表明聚氨酯混合料的力学强度与聚氨酯含量呈正相关,级配对混合料的力学性能影响不大。聚氨酯混合料的力学强度在压实后0~10 h内增长最快,10 h时达到最终劈裂强度的80%以上。在相同级配下,聚氨酯混合料的劈裂强度和马歇尔稳定度均超过沥青混合料的3倍,高温稳定性优于沥青混合料,动稳定度比沥青混合料高一个数量级。此外,聚氨酯混合料与沥青混合料的冻融劈裂强度比和飞散损失没有显著差异,具有优异的水稳定性和抗剥落性能。综上,AC型聚氨酯混合料具有优异的路用性能,为聚氨酯混合料在路面工程中的应用提供一定的参考。 相似文献