Abstract: The present disclosure relates to a support frame including a first pan-tilt connector and a leg assembly connected thereto and including a primary leg and a secondary leg. A leg adjustment structure is provided between and configured to unlock or lock the primary leg and the secondary leg, so that the primary leg and the secondary leg can move relative to each other or keep relatively stationary; the secondary leg comprises a first sub-leg and a second sub-leg which are configured such that the first sub-leg and the second sub-leg can be unfolded or folded with respect to each other; when the first sub-leg and the second sub-leg are unfolded, the primary leg, the first sub-leg and the second sub-leg are in a three-leg support state. The present disclosure further provides a photographing device, which comprises the support frame and an image acquisition apparatus mounted on the support frame.

Abstract: The present disclosure relates to the technical field of adjustment and installation of photography and video recording, in particular, to a quick-mounting structure, an adaptor ring and a filter. The quick-mounting structure includes a rotating groove body, wherein the rotating groove body is provided with a sliding groove therein, a notch is provided in the side wall of the sliding groove, and the rotating groove body is provided on the first connecting member; and a stopper, wherein the stopper is provided on the second connecting member, and can get into and out of the sliding groove through the notch.

Abstract: The present invention relates to a solid base catalyst including 10.0%-30.0% by weight of calcium oxide and 70.0%-90.0% by weight of zirconium oxide, in which the calcium source is CaCl2 or Ca(NO3)2, and the Zirconium source is ZrOCl2 or ZrO(NO3)2. The invention also provides a process for the preparation of the catalyst and a use of the catalyst in synthesizing dimethyl carbonate via heterogeneous catalysis. The catalyst shows good catalytic stability and catalytic activity, and can be separated from products easily and is reusable.