摘要:
Mesophilic xylanases derived from Acremonium cellulolyticus. A mesophilic xylanase I, derived from the mold Acremonium cellulolyticus, capable of non-specifically hydrolyzing xylan mainly into xylose, xylobiose and xylotriose, having an optimal pH at 3.5 and an optimal temperature for action at 55.degree. C. as determined by saccharifying activity for soluble xylan as a substrate and a molecular weight of 30,000 as determined by SDS-polyacrylamide gel electrophoresis. A mesophilic xylanase II having an optimal pH a 3.8, an optimal temperature for action at 55.degree. C. and a molecular weight of 25,500. A mesophilic xylanase III having an optimal pH at 3.5, an optimal temperature for action at 50.degree. C. and a molecular weight of 33,500.
摘要:
Organic materials such as raw refuse, waste plastics, waste biomass, sludges, etc. are decomposed by the use of supercritical water to selectively produce hydrogen. A thermochemical reaction is promoted to reduce the supercritical water and selectively produce hydrogen, without substantially adding any oxidizing agent to the supercritical water of a specific temperature and pressure, in the presence of a carbon dioxide-absorbing substance in an amount sufficient to absorb all of the generated carbon dioxide, so that carbon contained in the organic wastes reduces the supercritical water, and hence the organic materials are completely decomposed and also hydrogen gas is removed.
摘要:
Disclosed is an improvement in the process for the preparation of amorphous silicic acid particles useful, for example, as a filtration aid comprising the steps of a hydrothermal reaction to prepare calcium silicate particles and decalcification of the calcium silicate particles, after or without undertaking carbonation by the reaction of carbon dioxide, with an acid to form particles of amorphous silicic acid followed by drying of the amorphous silicic acid particles. Different from the conventional methods in which great shrinkage of the amorphous silicic acid cakes wet with water is unavoidable in the drying step to adversely affect the quality of the product, the final step of treatment preceding drying of the wet cake is undertaken in a liquid medium which is a mixture of water and a water-miscible organic solvent such as ethyl alcohol in a specified proportion so that the drying of the wet cake is performed without the disadvantage due to the large surface tension of water responsible to the drying shrinkage of wet cakes.
摘要:
A photocatalyst sheet capable of purifying the living environment by decomposing and removing malodorous substances and environment-polluting substances in the air, preventing development of bacterium, fungi, and protecting contamination, and a method for production thereof which comprises coating a solution of a titania sol on the surface of a sheet of organic substance such as plastic, and heating it under pressure to deposit the titanium powder on the surface of the sheet.
摘要:
When a saturated aqueous solution of a bolaform glycolipid represented by the general formula G--NH--CO--(CH.sub.2).sub.n --CO--NH--G, in which G is a residue derived from a D- or L-glucopyranose by excepting the reduced-terminal hydroxyl group and the subscript n is 10, 12 or 14, at a high temperature, e.g., 90 .degree. C. or higher, is cooled at a controlled rate of 0.5 .degree. C./minute or lower, crystallite growth of the precipitates proceeds to form an ultrafine fibrous assembly of up to several hundreds .mu.m length having a twisted fibrous morphology of right- or left-hand screw. The twisted fibrous assembly thus obtained has usefulness as a functional material in the field of fine chemicals and in the fields of electronic and information technologies.
摘要:
Disclosed is a novel .beta.-lactam compound, a 7-substituted-2-oxa-7-azabicyclo�3.2.0!heptan-6-one represented by the general formula ##STR1## in which R is an alkyl, cycloalkyl, aryl, halogen-substituted aryl or alkaryl group, having usefulness as an intermediate for the synthesis of various biologically active compounds. The compound can be prepared by the reaction of an isocyanate compound RNCO, R being the same as above, and 2,3-dihydrofuran, preferably, under pressurization up to 2000 atmospheres or higher.
摘要:
Proposed is a grain boundary-free crystalline body of a perovskite structure having a chemical composition of the formula Pr.sub.1-x M.sub.x MnO.sub.3, in which M is calcium or strontium and the subscript x is a number of 0.3 to 0.5, which exhibits a magnetoresistance behavior with a phase transition between an insulator phase and a ferromagnetic metallic phase accompanied by the phenomenon of hysteresis. This grain boundary-free crystalline body can be obtained by subjecting a sintered body of a powder blend consisting of the oxides of praseodymium, manganese and calcium or strontium to a crystal growing treatment by the floating zone-melting method in an atmosphere of oxygen.
摘要:
Proposed is a dielectric thin film of a substituted lead titanate having a chemical composition expressed by the formulaPb(Ti.sub.1-x M.sub.x)O.sub.3in which the subscript x is a positive number in the range from 0.05 to 0.50 and M is an element selected from the group consisting of niobium, tantalum, vanadium, antimony, bismuth, arsenic, tungsten, hafnium, germanium, tin, aluminum and gallium substituting for a part of the titanium atoms in the perovskite crystal lattice of lead titanate. Different from thin films of unsubstituted lead titanate or conventional substituted lead titanates, the above defined dielectric thin films of the invention are free from the disadvantage that the dielectric constant of the thin film is greatly decreased when the thickness of the thin film is so small as to be 1 .mu.m or smaller so that the dielectric constant of the inventive dielectric thin film having a thickness of 0.5 .mu.m or even smaller can be as large as 10 times of that of the thin film of unsubstituted lead titanate having the same thickness.
摘要:
The invention provides a carbonaceous ferromagnetic material consisting substantially of carbon alone as prepared by the carbonization of a specific aromatic compound, such as phenazine and indigo, to such an extent that the hydrogen atoms in the starting aromatic compound are eliminated as completely as possible but graphitization of the carbonization product does not take place by conducting the carbonization treatment at a temperature not exceeding 800.degree. C. The carbonization reaction can be promoted by admixing the aromatic compound with a compound of a ferromagnetic metallic element such as cobalt chloride, which is removed from the carbonization product by dissolving away with hydrochloric acid and ammonia water. Elimination of hydrogen atoms from the aromatic compound can be more complete by conducting the heat treatment for the carbonization in an atmosphere containing a halogen-generating agent such as carbon tetrachloride.
摘要:
An efficient method is proposed for the recovery of gold value contained in an aqueous solution even in a very low concentration of the ppb level. Namely, an aqueous acidic solution containing gold value in the form of complex gold anions, e.g., chloro complex anions of gold, is contacted with a solid ion exchanger which is prepared by the adsorption of a 2-hydroxyethyl tri(C.sub.8-12)alkyl ammonium halide on porous resin beads of a polymer of methacrylic acid ester so that the complex gold anions are adsorbed by the ion exchange reaction to form ion pairs with the quaternary ammonium cations. The thus adsorbed complex gold anions coupled with the quaternary ammonium cations can be eluted out of the adsorbent with an organic solvent such as alcohols and ketones in a quantitative yield of recovery.