This conclusion makes it clear that there is mathematic relationship between parameter ellipsoid and latitudinal density, and we have full reasons to do research on latitudinal density and latitudinal density anomaly.

This paper presents the concept of "latitudinal density anomaly"and"latitudinal gravity"on the basis of viewpoint of"latitudinal normal density hypothesis",and then,puts forward a"latitudinal gravity mode of plate movement".

These research approaches include uniform ellipsoid,parameter ellipsoid,latitudinal density ellipsoid,quasi-level ellipsoid and density level ellipsoid.

The main mechanical properties in warp and weft direction of the hollow integrated core sandwich composites are obtained by edgewise tensile,edgewise compression,flatwise tensile,flatwise compression,double lap shear,and four point bending experiments.

Discussion of Weft Stop of Air-jet Loom;

Reducing weft stop is an important way of improving efficiency of air-jet loom.

Warp stop and weft stop, especially the latter, are the main reasons that cause dropping efficiency of air-jet loom.

The reasons which cause the defects have been analyzed,and afterwards,the measures to prevent and cure weft direction defects have been introduced from points of view of yarn property,loom condition and technique.