大旋流

The flow features of a self-excited precessing jet,which was generated based on the wall attachment effect,were analyzed in the paper;and the large eddy simulation approach was used to numerically study the flow inside a precessing jet nozzle.

分析了基于流体附壁效应而自激产生的旋进射流的流动特征，采用大涡模拟方法研究了射流喷嘴内部的流场。

As a downstream piping system when the valve opens, reflux valve, when closed, the main medium used to prevent backflow to prevent the pump and drive motor reversal, as well as a container medium discharge; currently the most commonly used is the valve flap around the body Swing Pin rotation flap valve and the valve body along the vertical axis to move lift check valve, but the above two kinds of structures exist in the valve closed, medium speed back quickly from the largest drop to zero, inlet side of the pipe resulted in the rapid pressure rise, resulting Proportional Pressure Reducing Valves in damaging effects on the piping system of water hammer phenomenon, it is generally a diameter of valve production of 50 ~ 500 mm.

止回阀作为管道系统顺流时开启，逆流时关闭的阀门，主要用于防止介质倒流，防止泵及驱动电机反转以及容器内介质泄放；目前使用最普遍的是阀瓣围绕阀体销轴旋转的旋启式止回阀和阀瓣沿着阀体垂直中心线移动的升降式止回阀，但以上2种结构的阀门均存在关闭时介质倒流速度从最大迅速降为零，致使管道进水管一侧内压迅速升高，从而产生对管路系统有破坏作用的水锤现象，所以一般止回阀生产口径为50～500 mm。

It showed that the influences from gyro zero-position,rocket thrust eccentricity,launch mode and downwash flow field caused by helicopter are evident.

分析结果认为导弹陀螺零位、发动机推力偏心、导弹发射方式、直升机旋翼下洗流场等因素的影响是显著的，特别是在这些因素的综合影响下，初始弹道将出现很大的偏离。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。