管道防腐层现场补口及补伤工艺探索

介绍了输油输气管道现场补口及补伤的方式和方法，并从实际工作中总结了施工质量的控制要点。     

Conceptual rotational mode design for optical conical scanning imaging small satellites

This paper focuses upon the novel optical conical scanning imaging working mode design for small satellites. This kind of satellite employs only one inclined optical camera achieving wide-swath imaging via a rotational motion about the nadir axis either by the camera or by the satellite. Three working modes are designed, i.e., high-speed rotational mode, low-speed rotational mode,and variable-speed rotational mode. For the high-speed and low-speed working modes, the camera rotates at a constant speed and the corresponding angular velocity is derived under the consideration of guaranteed coverage and minimized overlap. To improve the system performance, an enhanced working mode taking advantages of both the high-speed rotational mode and lowspeed rotational mode is proposed. Working in this variable-speed rotational mode, the camera rotates slowly to get high-quality pictures when it works, while it rotates rapidly to reduce the energy consumption and save the storage during which period the camera is turned off to minimize the overlap. All these working modes are illustrated in detail, and numerical simulation tests are conducted to validate their effectiveness.