为考察ANSOB氧枪工作中发生烧损时的喷流特性,在等温条件下对模拟氧枪的同轴环状喷流在枪端面齐平、有30°和45°角缺损,以及环流不供气等4种情况下实测了时均速度和紊流度分布,得出了在
Fighting the novel coronavirus disease (COVID-19) has been a family affair for Liu Yuanli, a professor of health policy and management and Dean of the School of
渤海是北半球纬度最低的结冰海,黄河入海口海域位于渤海的西南区域。近年来随着这一海域海岸工程及海洋采油蓬勃发展,进海路的建设造成了大量半封闭海域,改变了该海域的海水动力
Brazilian President Jair Bolsonaro announced on July 7 that he tested positive for the novel coronavirus disease (COVID-19). The 65-year-old is considered to be
本论文采集了2015年11月~2016年5月和2016年9月~2017年8月石家庄市PM_(10)、PM_(2.5)和PM_1样品,通过测定其化学组分:无机元素、水溶性离子、碳组分(OC、EC和WSOC)、多环芳烃和正构烷烃,分析了石家庄市PM_(10)、PM_(2.5)和PM_1浓度水平与时空变化特征,并通过计算各组分间相关性、特征化合物比值、主成分分析和PMF源解析法分析了石家庄市大气颗粒物污
The unexpected outbreak of the COVID-19 pandemic is the most seri-ous global public health emergency that humanity has experienced since the end of World War II
At a time of global uncertainty amid the novel coronavirus disease (COVID-19) pandemic and an economic recession, China is taking firm and steady steps to promo