摘要:
The present invention relates to biocompatible, biodegradable polyurethane/urea polymeric compositions that are capable of in-vivo curing with low heat generation to form materials suitable for use in scaffolds in tissue engineering applications such as bone and cartilage repair. The polymers are desirably flowable and injectable and can support living biological components to aid in the healing process. They may be cured ex-vivo for invasive surgical repair methods, or alternatively utilized for relatively non-invasive surgical repair methods such as by arthroscope. The invention also relates to prepolymers useful in the preparation of the polymeric compositions, and to methods of treatment of damaged tissue using the polymers of the invention.
摘要:
This invention relates to catalysts comprising a catalytic metal deposited on a composite support with well-dispersed chemical “anchor” species acting as nucleation centers for catalytic metal crystallites growth. The catalysts have the advantage that the average catalytic metal crystallite size can be controlled by the molar ratio of catalytic metal to chemical “anchor,” and is not limited by the porous structure of the support. A preferred embodiment comprises a cobalt-based catalyst on a silica-alumina support made by a co-gel method, wherein its average pore size can be controlled by the pH. The alumina species in the support most likely serve as chemical “anchors” to control the dispersion of cobalt species, such that the average cobalt crystallite size can be greater than the average pore size.
摘要:
A catalyst material for carbon nanotube synthesis includes a uniform dispersion of host particles on a substrate. The host particles themselves include catalyst nanoparticles that are effective to catalyze nanotube syntheses reactions and provide nucleation sites. Methods for preparing catalyst materials include co-sputtering a catalytic species and a host species to form a precursor thin film on a substrate, followed by an oxidation reaction of the precursor thin film in air. The precursor thin film can be patterned on the substrate to limit the locations of the catalyst material to well-defined areas. Methods for nanotube synthesis employ CVD in conjunction with the catalyst materials of the invention. During the synthesis, the catalyst nanoparticles catalyze carbon nanotubes to grown from a carbon-containing gas.
摘要:
A process for preparing a hydrocyanation catalyst comprising contacting a bidentate phosphorous-containing ligand with nickel chloride in the presence of a nitrile solvent and a reducing metal which is more electropositive than nickel the nickel chloride being introduced as an aqueous solution and the water being removed concurrently with the reduction reaction by azeotropic distillation.
摘要:
Metallic nanoparticles coated with a mixed monolayer with well defined thickness or length are prepared. The mixed monolayer comprises a capture coating component useful for the specific capture of materials and a shielding coating component for elimination of non-specific binding of materials to the capture component.
摘要:
A method of forming a composite structure for an ion transport membrane in which a filler substance is applied to one surface of a porous support layer in order to plug pores and prevent coated ion conducting material from penetrating the pores to reduce the amount of gas diffusion. Prior to coating of the surface with layers that may be oxygen ion conducting layers, excess filler substance is removed. After the coating of the one surface, the filler substance is removed from pores.
摘要:
Ferrierite is prepared by a method that provides extremely pure crystalline material. The method consists of preparing a mixture of silica, alumina, alkali metal and pyridine of a certain composition and heating said mixture to form the crystals. The SiO.sub.2 /Al.sub.2 O.sub.3 and OH.sup.- /SiO.sub.2 are controlled to insure preparation of high SiO.sub.2 /Al.sub.2 O.sub.3 ratio, high surface area and high purity ferrierite. An improved olefin skeletal isomerization catalyst is prepared from a high silica to alumina ratio, high surface area and high purity ferrierite.
摘要翻译:镁镁沸石通过提供极纯的结晶材料的方法制备。 该方法包括制备具有一定组成的二氧化硅,氧化铝,碱金属和吡啶的混合物,并加热所述混合物以形成晶体。 控制SiO 2 / Al 2 O 3和OH- / SiO 2以确保制备高SiO 2 / Al 2 O 3比例,高表面积和高纯度镁碱沸石。 改进的烯烃骨架异构化催化剂由高二氧化硅与氧化铝比,高表面积和高纯度镁碱沸石制备。
摘要:
Dust emission is controlled by a preferably short fill at the expulsion end of each chamber, and selective venting of residual pressure through the air-inlet end. This selective venting is accomplished through use of a novel seal or "pad" that has an extension for tightly covering and sealing the material-exhaust end of each chamber while the chamber is in a dust-control plenum. The pad extension is notched so that it leaves the air-inlet end uncovered, permitting pressure venting through the notch and the air-inlet end. To provide truly effective sealing of the pad extension against the wear plate above the chamber that is in the plenum, the extension is reinforced by a strong metal plate which is embedded in the pad. Careful contouring of the main material-conveying ports in the pad optimizes the performance. A new all-pneumatic pad-clamping pressure-control system has been found to provide excellent control of pressure and uniformity of wear, with a minimum of working parts and adjustments.
摘要:
A process for the gas-phase polymerization of polymers which allows for the introduction of an unsupported polymerization catalyst system into the gas-phase reactor, wherein the unsupported polymerization catalyst system comprises (i) a non-volatile materials fraction containing a polymerization catalyst; (ii) a solvent fraction which is at least partially miscible with the non-volatile materials fraction and which is sufficiently volatile to allow for the formation of polymerization catalyst particles when the mixture of the solvent fraction and the non-volatile materials fraction is sprayed into the reactor; (iii) a compressed fluid; and (iv) optionally a slowly vaporizing solvent.
摘要:
The method enables the creation of a pillared layered clay (a PILC) by contacting the clay with a pillaring precursor and delivering energy to the reaction mixture to intercalate the precursor into the clay. The pillaring precursor is an electrically neutral organometallic molecule with a carbon-metal bond which is susceptible to proton attack whereby protons donated from sites of Bronsted acidity in the clay cleave the carbon-metal bond to yield an organic fragment of the precursor and a metal-containing pillaring fragment. A preferred precursor is Ph.sub.2 SnCl.sub.2.