摘要:
A method of preparing a catalyst for producing acrolein by oxidation of propylene at high space velocity, said catalyst is a Mo—Bi—Fe—Co based composite metal oxide. Producing unsaturated aldehyde via partial oxidation of lower unsaturated olefin at high space velocity using said catalyst is suitable for process with or without off-gas recirculating. Said catalyst is prepared by co-precipitation, the reaction conditions for using said catalyst to produce unsaturated aldehyde are, the space velocity of unsaturated lower olefin relative to catalyst being 120˜200 h-1(STP), reaction temperature being 300˜420° C. and absolute pressure being 0.1˜0.5 MPa; a single-stage unsaturated lower olefin conversion ratio of greater than 98.0% and carbon oxide yield of less than 3.3% with an overall yield of unsaturated lower aldehyde and acid of greater than 94.0% are obtained. The process to prepare the said catalyst is simple, easy to be repeated, and capable of industrial scale-up.
摘要:
A prosthetic heart valve has an annular valve-perimeter-shape-defining structure having a radially outer surface. A clip structure is provided on the outer surface. This clip structure is used to attach flexible valve leaflets to the shape-defining structure. One or more retainer members may be used to help hold the leaflets in the clip structure.
摘要:
The present invention provides a preparation process of complex oxides catalyst containing Mo, Bi, Fe and Co, which comprising steps as following: dissolving precursor compounds of the components for catalyst and complexing agent in water to obtain a solution, and then drying, molding and calcining the solution to obtain catalyst. The catalyst is used for gas phase oxidation of light alkenes to unsaturated aldehydes. The catalyst has high activity, selectivity and stability. The reaction condition is mild. The preparation process of the catalyst is easy to operate and can be used for mass production.
摘要:
A prosthetic heart valve of the type that includes a hollow annular stent and a plurality of flexible leaflets that are attached to the stent. One or more fixture structures are used to attach the leaflets to the stent so that sutures do not have to be used for that purpose. The fixture structures preferably extend annularly at least substantially all the way around the valve. Surfaces of the fixture structures that can come into contact with portions of the leaflets that move during use of the valve can be shaped to help beneficially shape those leaflet portions during their movements.
摘要:
A pharmaceutical composition for treatment of chronic liver diseases, the composition including at least cordyceps sinensis polysaccharide, amygdaloside, and gypenoside. The pharmaceutical composition slows down liver fibrosis, stops the development thereof, or reverses the same. A method of using the pharmaceutical composition for treatment of chronic liver diseases.
摘要:
A prosthetic heart valve includes an annular stent structure having a plurality of annularly spaced stent post regions, a plurality of leaflets that extend radially inward from the stent structure and that include radially outer portions that lie against a radially outer surface of the stent structure, and a clamping structure that is radially outside the other components and that clamps the radially outer portions of the leaflets against the radially outer surface of the stent structures to secure the leaflets to the stent structure. The above-described structural arrangement applies to the stent post regions as well as to other portions of the stent structure.
摘要:
The present invention provides a complex oxide catalyst whose general formula is Mo12VaCubWcXdYeOf/Z. reducing agent needs to be added into the catalyst during the preparation process of the active component of the catalyst and (or) molding process of the catalyst. Specifically, X is at least one selected from a group consisting of Nb, Sb, Sr, Ba and Te; Y is at least one selected from a group consisting of La, Ce, Nd, Sm and Cs; “a” is ranging from 2 to 8; “b” is ranging from 1 to 6; “c” is ranging from 0.5 to 5; “d” is ranging from 0.01 to 4; “e” is ranging from 0.01 to 4; f is determined by the oxidation state of the component element; Z is silicon powder; the reducing agent is C2˜C6 diol or polyol.
摘要:
A prosthetic heart valve includes a stent having a collapsed condition and an expanded condition. The stent includes a plurality of cells, each cell being formed by a plurality of struts, and a plurality of commissure features. The heart valve further includes a valve assembly secured to the stent and including a cuff and a plurality of leaflets, each leaflet being attached to adjacent commissure features and to the stent struts and/or the cuff.
摘要:
A mandrel (5) for molding polymer valve leaflets for heart valve prostheses is disclosed, including a body portion (52) including an outer surface with ridges (60) and contoured surfaces (64) corresponding to the leaflets, the upper edge of the contoured surfaces corresponding to the free upper edge of the leaflets, and the mandrel including a mandrel extension (54) above the body portion, and a gap (68) extending around the mandrel between the upper edge of the contoured surface and the mandrel extension. A process for producing these polymer valve leaflets is also disclosed by dip coating with this mandrel and re-moving the polymer film created at the gap, preferably by applying suction or blowing thereto.
摘要:
The present invention provides a complex oxide catalyst whose general formula is Mo12VaCubWcXdYeOf/Z. reducing agent needs to be added into the catalyst during the preparation process of the active component of the catalyst and (or) molding process of the catalyst. Specifically, X is at least one selected from a group consisting of Nb, Sb, Sr, Ba and Te; Y is at least one selected from a group consisting of La, Ce, Nd, Sm and Cs; “a” is ranging from 2 to 8; “b” is ranging from 1 to 6; “c” is ranging from 0.5 to 5; “d” is ranging from 0.01 to 4; “e” is ranging from 0.01 to 4; f is determined by the oxidation state of the component element; Z is silicon powder; the reducing agent is C2˜C6 diol or polyol.