Subjects: Nuclear Science and Technology >> Nuclear Science and Technology submitted time 2024-05-07
Abstract：蒸汽发生器传热管是压水堆核电站一回路的关键压力边界，正常运行及事故条件下的系统运行参数，直接影响着传热管结构的完整性。为进一步对传热管的结构响应特性进行研究，建立了两种主流排列方式的传热管局部模型，并分别进行了正常运行和典型事故参数下的流固耦合计算和对比分析，获得了一、二次侧流体共同作用下的传热管关键部位的载荷变化规律。结果表明，在相同的流动条件下，传热管叉排模型的应力和变形均大于顺排模型；传热管根部横截面的等效应力沿壁厚方向先减小再增大，中部横截面的等效应力沿壁厚方向呈现近似线性降低；在传热管根部区域，内、外壁面的等效应力沿轴向高度先迅速降低而后快速升高，并形成应力平台。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-09 Cooperative journals: 《干旱区研究》
Abstract：根据新疆北部40个站点1961—2016年逐日气温、降水数据，采用数理统计、倾向率法、Mann-Kendall突变检验和小波分析等方法，研究北疆地区近56 a气候变化特征、变化趋势以及变化的空间差异。结果表明：在研究时段内，气候总体呈气温升高、降水量增加的暖湿化趋势，年平均气温以0.34 ℃·(10a)-1速率上升，年降水量递增速率12.05 mm·(10a)-1；Mann-Kendall突变检验显示，气温在1991年发生突变后升高，降水量1987年出现突变后逐渐增多；年平均气温变化表现出6 a、14 a和28 a周期性规律，降水量变化有4 a、12 a和22 a的规律；在空间上，气温增速东西大于南北，降水量增量山区多于平原和盆地，西部多于东部。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2019-09-09 Cooperative journals: 《干旱区研究》
Abstract：根据新疆北部40个站点1961—2016年逐日气温、降水数据，采用数理统计、倾向率法、Mann-Kendall突变检验和小波分析等方法，研究北疆地区近56 a气候变化特征、变化趋势以及变化的空间差异。结果表明：在研究时段内，气候总体呈气温升高、降水量增加的暖湿化趋势，年平均气温以0.34 ℃·(10a)-1速率上升，年降水量递增速率12.05 mm·(10a)-1；Mann-Kendall突变检验显示，气温在1991年发生突变后升高，降水量1987年出现突变后逐渐增多；年平均气温变化表现出6 a、14 a和28 a周期性规律，降水量变化有4 a、12 a和22 a的规律；在空间上，气温增速东西大于南北，降水量增量山区多于平原和盆地，西部多于东部。
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2019-01-28 Cooperative journals: 《计算机应用研究》
Abstract： At present, particle swarm optimization coverage algorithm has been widely applied due to its advantages such as fewer parameters; faster computation speed and easier algorithm. However, there are still some defects, for example the slow convergence speed and falling into the local optimal value easily, causes "premature". In order to improve the performance of wireless sensor network, the distribution of nodes and coverage scheme was studied. A Quasi-physical particle swarm optimization algorithm based on inertia weight was proposed. The quasi-gravitational force and quasi-coulomb force in the Quasi-physical force algorithm were combined with the particle swarm optimization algorithm. It enhances the global search ability, converges to the global optimal solution faster, and reduces the consumption and repeated covering. The simulation results prove that the faster global convergences, higher coverage, lower rate of repeat coverage are achieved than the basic particle swarm optimization and standard particle swarm optimization particle swarm optimization hm based on inertia weight.
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