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实际上,长江沿岸港口对“第一大港”的争夺也从未停止。且不说沿江而下有江苏、上海崛起的港口群,继南京稳坐中国内河第一大港口交椅后,2010年,湖北拟投入百亿元,抢夺第二大港交椅。就在长江上游,保税港也早已花落重庆。 相似文献
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为研究CRTSⅢ型无砟轨道板在太阳辐射、环境温度及其他自然因素影响下的温度场分布及演化特征,基于昌吉赣高速铁路丰城段CRTSⅢ型无砟轨道板现场实验开展研究,通过传热学的基本原理构建轨道板温度场解析解模型,研究轨道板内温度场的变化.研究结果表明:CRTSⅢ型轨道板上表面与环境温度变化基本同步,下表面与环境温度变化之间存在... 相似文献
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跨文化是现代国际商务活动的一个重要方面,有考虑到跨文化沟通的重要性而使商务活动进行的更加顺利的,也有因为不了解跨文化沟通而使得跨文化冲突阻碍商务活动进行的。本文主要论述了这种跨文化现象,分析什么是跨文化冲突,其原因和表现有哪些。进而说明跨文化沟通的重要性,先述说跨文化沟通的含义,再介绍如何进行跨文化沟通。 相似文献
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目的利用复杂网络理论比较青少年首发未用药抑郁症患者与正常对照组之间大脑小世界功能网络拓扑结构的异同点,以期进一步阐明青少年抑郁症患者的神经病理发病机制。方法共纳入研究对象32例,青少年抑郁症患者组16例,符合美国精神疾病诊断与统计手册第4版(DSM-IV)的首发单相青少年抑郁症患者,以往从未接受过任何治疗;正常对照组16名,两组间年龄、教育程度相匹配。所有被试对象均为右利手。采用不同的相关系数作为阈值构建大脑复杂网络。结果青少年首发未服药患者组大脑神经网路拓扑结构,较正常健康对照呈现一种相对无序混乱的状态。青少年抑郁症组大脑网络小世界特性明显下降,神经网络整体运行效率下降。杏仁核在大脑拓扑结构中度值上升,杏仁核与颞叶皮层、杏仁核与顶叶皮层、杏仁核与中央后回、前额叶与顶下小叶等脑区之间功能连接增高,并且功能连接改变与患者病程呈正相关。青少年抑郁症组中,静息态背景下,前扣带回、前额叶背外侧段、前额叶内侧段、前额叶下段、岛叶和颞叶皮层度值增加。结论杏仁核在抑郁症发生、发展中起重要的作用,有关杏仁核的神经网络拓扑结构异常可能是潜在的青少年抑郁症患者抑郁易感性、疾病发展的生物学标记。抑郁症患者大脑多个脑区存在结构和功能的异常。 相似文献
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Objective To develop a classification tree algorithm to improve diagnostic performances of 99mTc-MIBI SPECT/CT fusion imaging in differentiating solitary pulmonary nodules (SPNs). Methods Forty-four SPNs, including 30 malignant cases and 14 benign ones that were eventually pathologically identified, were included in this prospective study. All patients received 99Tcm-MIBI SPECT/CT scanning at an early stage and a delayed stage before operation. Thirty predictor variables, including 11 clinical variables, 4 variables of emission and 15 variables of transmission information from SPECT/CT scanning, were analyzed independently by the classification tree algorithm and radiological residents. Diagnostic rules were demonstrated in tree-topology, and diagnostic performances were compared with Area under Curve (AUC) of Receiver Operating Characteristic Curve (ROC). Results A classification decision tree with lowest relative cost of 0.340 was developed for 99Tcm-MIBI SPECT/CT scanning in which the value of Target/Normal region of 99Tcm-MIBI uptake in the delayed stage and in the early stage, age, cough and specula sign were five most important contributors. The sensitivity and specificity were 93.33% and 78. 57e, respectively, a little higher than those of the expert. The sensitivity and specificity by residents of Grade one were 76.67% and 28.57%, respectively, and AUC of CART and expert was 0.886±0.055 and 0.829±0.062, respectively, and the corresponding AUC of residents was 0.566±0.092. Comparisons of AUCs suggest that performance of CART was similar to that of expert (P=0.204), but greater than that of residents (P<0.001). Conclusion Our data mining technique using classification decision tree has a much higher accuracy than residents. It suggests that the application of this algorithm will significantly improve the diagnostic performance of residents. 相似文献
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公路修筑和养护中,经常遇到岩石开凿作业,这是较难“啃”的硬骨头。原有公路的拓宽、降坡、取直等改造工作其工程规模小,工作量不大,一般难以配备成套的机械施工设备,有的采取手工作业,费时费力,效率很低,有的因为公路改造影响运输。因此,公路改造中很需要一种转移轻便、工效较高、自备能源的小型石方开拓机具来“啃”零零星星的硬骨头,既改善劳动条 相似文献
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