摘要:
Proposed is an efficient method for the preparation of vitreous hollow microspheres from particles of a vitreous volcanic deposit by a heat treatment to effect expansion of the particles by foaming. The inventive method comprises a step, prior to the heat treatment for expansion of the particles, in which the starting particles are dispersed in an aqueous medium containing aluminum sulfate and urea each in a specified concentration followed by a heating treatment of the dispersion so as to deposit a coating layer of aluminum hydroxide on the particle surface so that the efficiency of foaming can be greatly improved without the disadvantage of particle agglomeration.
摘要:
Disclosed is a method for the preparation of a .beta.-thiolactam compound, i.e. a 7-substituted-2-oxa-7-azabicyclo [3.2.0]-heptan-6-thione, represented by the general formula ##STR1## in which R is an alkyl or aryl group, having usefulness as an intermediate for the synthesis of various biologically active compounds. The compound can be prepared by the reaction of an isothiocyanate compound R--NCS, R being the same as above, and 2,3-dihydrofuran, preferably, under pressurization up to 2000 atmospheres or higher at an elevated temperature.
摘要:
A novel method is proposed for the preparation of a superlattice multilayered film, which has a multilayered structure alternately consisting of epitaxially grown layers of a metal and layers of a metal oxide formed on the surface of a substrate and is useful as high-speed electronic devices, soft X-ray reflectors, neutron beam polarizers and the like. According to the discovery leading to this invention, good epitaxial growth of the layers can be accomplished when the metal has a face-centered cubic lattice structure and the metal oxide has a sodium chloride-type cubic lattice structure and the difference in the lattice constant between the metal and the metal oxide is small enough as in the combinations of silver and nickel oxide or magnesium oxide and nickel and nickel oxide.
摘要:
Proposed is a method for bonding of a ceramic body and a metallic body at a relatively low temperature not to cause substantial deformation or material degradation of the ceramic and metallic materials. The surface of the ceramic body is first irradiated with laser beams in vacuum so that the inorganic non-volatile constituent of the ceramic material, e.g. silicon when the ceramic is silicon nitride, is isolated on the surface of the ceramic body forming a layer. Thereafter, the metallic body is brought into contact with and pressed in vacuum against the thus laser beam-irradiated area of the ceramic body under an adequate pressing force and at an elevated but relatively low temperature which is, for example, not higher than 0.5Tm .degree.C., Tm .degree.C. being the melting point of the metallic material, so that the ceramic and metallic bodies are firmly bonded together. It is preferable that the surface of the metallic body is subjected beforehand to an activation or cleaning treatment, for example, by the bombardment with ion beams of an inert gas, e.g., argon.
摘要:
Proposed is a method for vascular embolization of the blood vessel of a patient by introducing an aqueous solution of a specific thermosensitive polymer, which is liquid at low temperatures but causes coagulation when heated up to the body temperature of the patient, into the blood vessel followed by in situ heating of the solution. The thermosensitive polymer found to be suitable for the purpose is a homopolymer or copolymer of an N-substituted (meth) acrylamide monomer having a specified intrinsic viscosity in tetrahydrofuran and gives an aqueous solution capable of exhibiting phase transition from a liquid to a coagulate at a transition temperature of 10.degree. to 37.degree..
摘要:
A novel and efficient electrochemical method is disclosed for the recovery of lithium value from an aqueous solution containing lithium ions in a relatively low concentration together with ions of various kinds of other metallic impurity elements. The method comprises electrochemical selective adsorption of lithium ions from the aqueous solution on to a specific working electrode by applying a DC voltage of a relatively low DC voltage of 0.1-0.4 volt versus a saturated calomel electrode to the working electrode as the cathode opposed to a counterelectrode as the anode and then desorption of the lithium ions therefrom by applying a DC voltage of 0.7-1.2 volts versus a saturated calomel electrode to the lithium-bearing working electrode as the anode opposed to a counterelectrode as the cathode in an aqueous desorption medium containing an electrolyte such as a lithium salt. At least the surface layer of the working electrode is formed from an oxide of manganese prepared by admixing a manganese compound with a limited amount of a lithium or magnesium compound, converting the mixture into oxides by a heat treatment in an oxidizing atmosphere and then removing the lithium or magnesium therefrom by leaching in an acid solution or by an electrochemical means.
摘要:
A particle-size distribution analyzer in a vent gas or flue gas which can be in a gas carrying line of a dust- and/or mist-producing process is provided. The analyzer comprises: a series of particle-size classifying units each consisting of a gas-ejection nozzle of an opening having a diameter different from the others and an impaction plate mounted on a revolvable turret in such a fashion that the series of the units can communicate with a suction nozzle in the gas flow line one by one successively in a decreasing order of the nozzle opening diameter; and a light-scattering particle-concentration detecting system which gives the concentration data after particle-size classification as a function of the cut-off size of the particles contained in the gas. In another embodiment, a heater to evaporate the liquid constituent in the mist particles and a second concentration-detecting system are provided downstream of the first concentration-detecting system so that measurements of the particle size distribution can be conducted for the dust particles and mist particles separately.
摘要:
Ultra-fine hollow glass spheres suitable as a filler in light-weight composite materials for building use and the like can be prepared from a fine powder of volcanic glass even when the starting powder has a particle size as fine as 20 .mu.m or smaller. The inventive method comprises an acid-leaching treatment of the starting powder using hydrochloric or sulfuric acid under hydrothermal conditions at 150.degree.-200.degree. C. to modify the chemical composition in the surface layer of the particles and a subsequent heat treatment of the acid-treated particles at a specified high temperature to effect expansion by the water vapor produced from the structural water in the softened particles. By virtue of the modified composition in the surface layer and in contrast to the prior art method without the acid treatment, a good balance can be obtained between the rate of water vapor release and softening of the particles even when the particle size is extremely small to facilitate expansion of the particles.
摘要:
A membrane of an ionic pendant-containing, water-insoluble copolymeric poly(amino acid) composed of a first moiety derived from a first amino acid which gives a water-soluble poly (amino acid) with ionic groups of carboxyl and/or amino groups as the pendants to the molecule, e.g., glutamic acid, aspartic acid, lysine and ornithine, and a second moiety derived from a second amino acid which gives a water-insoluble poly (amino acid), e.g., leucine, alanine and methionine, in a specified molar proportion serves as a functional element of an electronic device such as a non-linear resistor capable of working in an aqueous medium and exhibiting a non-linear voltage-current relationship or a phenomenon of hysteresis in the voltage/current scanning.
摘要:
Disclosed is a novel cathode ray-luminescent phosphor which is a composite body consisting of a dealuminized zeolite carrying a specified amount of a metal such as tin, cobalt and nickel or an oxide thereof within the pores of the dealuminized zeolite structure. The cathode ray-luminescent phosphor is prepared by a method comprising the steps of: (a) heating an ammonium-form zeolite in the presence of steam to effect dealuminization of the zeolite; (b) impregnating the dealuminized zeolite with an aqueous solution of a metal salt in an amount of the metal salt in the range from 10 to 60 parts by weight calculated as metal per 100 parts by weight of the dealuminized zeolite; (c) drying the dealuminized zeolite impregnated with the aqueous metal salt solution; and (d) calcining the dried zeolite in a reducing or oxidizing atmosphere at a temperature in the range from 450 to 600.degree. C. for 1 to 5 hours to form a composite of the dealuminized zeolite and the metal or an oxide of the metal, respectively.