Preparing and Characterization of Hollow Ceramic Microspheres

The hollow microsphere is a kind of new materials. It has a bright future for its excellent comprehensive performance. This article introduces a high-temperature synthetic technology on the basis of SHS to prepare new hollow ceramic microspheres. Reaction mechanism of hollow ceramic microspheres was studied. Results show that sphere, similar sphere and irregular powders constitute the spraying products. Sphere and similar sphere powders are hollow structure. Besides it also recommend the self-made equipments of collection that adopts three kinds of collections methods of static electricity, water and filter net. The total rate of collection raised above 80%.The effect is good. The hollow microsphere were analyzed through SEM and XRD, the hollow microsphere is regular spheroid or type spheroid.the size of the hollow microsphere is abort Similar. Its diameter is 20 μm or so. The equipments that experiment needs is simple, vivid craft and strong adaptability and respond that raw material and manufacturing circulate cost cheap.

Deriving the radial distances of wide coronal mass ejections from elongation measurements in the heliosphere – application to CME-CME interaction

We present general considerations regarding the derivation of the radial distances of coronal mass ejections (CMEs) from elongation angle measurements such as those provided by SECCHI and SMEI, focusing on measurements in the Heliospheric Imager 2 (HI-2) field of view (i.e. past 0.3 AU). This study is based on a three-dimensional (3-D) magneto-hydrodynamics (MHD) simulation of two CMEs observed by SECCHI on 24–27 January 2007. Having a 3-D simulation with synthetic HI images, we are able to compare the two basic methods used to derive CME positions from elongation angles, the so-called "Point-P" and "Fixed-φ" approximations. We confirm, following similar works, that both methods, while valid in the most inner heliosphere, yield increasingly large errors in HI-2 field of view for fast and wide CMEs. Using a simple model of a CME as an expanding self-similar sphere, we derive an analytical relationship between elongation angles and radial distances for wide CMEs. This relationship is simply the harmonic mean of the "Point-P" and "Fixed-φ" approximations and it is aimed at complementing 3-D fitting of CMEs by cone models or flux rope shapes. It proves better at getting the kinematics of the simulated CME right when we compare the results of our line-of-sights to the MHD simulation. Based on this approximation, we re-analyze the J-maps (time-elongation maps) in 26–27 January 2007 and present the first observational evidence that the merging of CMEs is associated with a momentum exchange from the faster ejection to the slower one due to the propagation of the shock wave associated with the fast eruption through the slow eruption.