concentrationratio相关论文
Compared to petroleum,coals have not been widely used as chemical feedstock because of the difficulty in isolating valua......
Insurance was one of the industries that opened thoroughly after China’s entry intoWTO.Although insurance experienced t......
目的分析玉溪市流感季节性特征及变化趋势，为制定防控策略提供科学依据。方法采用集中度和圆形分布法分析季节性，年估计百分比变化分......
分析讨论了复合抛物面型集光器与多模光纤的耦合效率和集光器设计之间的关系，提出了采用截底法和截顶法提高集光器与多模光纤耦合效......
