Abstract: An adsorbent for radioelement-containing waste composed of the following spherical layered double hydroxide (A) or spherical metal hydroxide (B) is provided. (A) is a nonstoichiometric compound represented by general formula (a) or (b): [M2+1-xM3+x(OH)2]x+[An?x/n·mH2O]x? . . . (a), [Al2Li(OH)6]x+[An?x/n·mH2O]x? . . . (b) wherein 0.1?x?0.4, 0<m, n represents a natural number of 1 to 4, M2+ represents at least one divalent metal, M3+ represents at least one trivalent metal, and An? represents at least one n-valent ion-exchangeable anion, and (B) is a spherical metal hydroxide containing a metal selected from the group consisting of the metal atoms belonging to Group II, Group IV, Group V, Group VI, Group XI, Group XII, and Group XIII of the periodic table, and the group consisting of Mn, Fe, Co, Ni, Pb, and Bi.

Abstract: Based on designs concerning boron nitride thin-films each including boron nitride crystals in acute-ended shapes excellent in field electron emission properties, and designs of emitters adopting such thin-films, it is aimed at appropriately controlling a distribution state of such crystals to thereby provide an emitter having an excellent efficiency and thus requiring only a lower threshold electric field for electron emission. In a design of a boron nitride thin-film emitter comprising crystals that are each represented by a general formula BN, that each include sp3 bonded boron nitride, sp2 bonded boron nitride, or a mixture thereof, and that each exhibit an acute-ended shape excellent in field electron emission property; there is controlled an angle of a substrate relative to a reaction gas flow upon deposition of the emitter from a vapor phase, thereby controlling a distribution state of the crystals over a surface of the thin-film.

Abstract: An adsorbent for radioelement-containing waste includes spherical layered double hydroxide (A) or spherical metal hydroxide (B). (A) is a nonstoichiometric compound represented by general formula (a) or (b): [M2+1-xM3+x(OH)2]x+[An?x/n.mH2O]x???(a), [Al2Li(OH)6]x+[An?x/n.mH2O]x???(b) where 0.1?x?0.4, 0<m. The n represents a natural number of 1 to 4, M2+ represents at least one divalent metal, M3+ represents at least one trivalent metal, and An? represents at least one n-valent ion-exchangeable anion. (B) contains a metal selected from the group of Group II, Group IV, Group V, Group VI, Group XI, Group XII, and Group XIII of the periodic table, and the group of Mn, Fe, Co, Ni, Pb, and Bi. This adsorbent efficiently adsorbs and collects volatile iodine, a radioactive anion in wastewater, etc. providing a crack-resistant solidified article after a solidification treatment, and effectively confines the radioelement-containing waste with long-term stability.

Abstract: In an electron emission method, a voltage is applied to a field electron emission element that has a boron nitride material containing crystal, formed on an element substrate to show a conical projection of the boron nitride material and shows a stable electron emitting property in an atmosphere when a voltage is applied thereto to emit electrons. An electron emission threshold of the field electron emission element falls due to formation of a surface electric dipolar layer by bringing it into contact with an operating atmosphere containing polar solvent gas when applying a voltage to the field electron emission element so as to emit electrons.

Abstract: A membrane body of sp3-bonded boron nitride has excellent field electron emission. The membrane body can withstand high intensity of electric field, allows the enhanced emission of electrons resulting in a high density of current, and does not degrade during long use. The membrane body includes a surface texture in a self-organized manner by vapor-phase deposition.

Abstract: An adsorbent for radioelement-containing waste composed of the following spherical layered double hydroxide (A) or spherical metal hydroxide (B) is provided. (A) is a nonstoichiometric compound represented by general formula (a) or (b): [M2+1-xM3+x(OH)2]x+[An?x/n.mH2O]x? . . . (a), [Al2Li(OH)6]x+[An?x/n.mH2O]x? . . . (b) wherein 0.1?x?0.4, 0<m, n represents a natural number of 1 to 4, M2+ represents at least one divalent metal, M3+ represents at least one trivalent metal, and An? represents at least one n-valent ion-exchangeable anion, and (B) is a spherical metal hydroxide containing a metal selected from the group consisting of the metal atoms belonging to Group II, Group IV, Group V, Group VI, Group XI, Group XII, and Group XIII of the periodic table, and the group consisting of Mn, Fe, Co, Ni, Pb, and Bi.

Abstract: The present invention provides a sp3-bonded boron nitride, represented by a general formula BN, having a hexagonal 5H or 6H polytypic form and having a property of emitting light in ultraviolet region. Its producing method comprises: introducing reaction mixed gas containing boron and nitrogen being diluted with dilution gas into a reaction chamber; and irradiating a surface of a substrate placed in the chamber, a growing surface on the substrate, and a growing spacing region about the growing surface with ultraviolet light to cause gas phase reaction, thereby generating, depositing, or growing the boron nitride on the substrate.

Abstract: There are provided an electron emission element that operates stably in the atmosphere, a method of manufacturing the same and a method of emitting field electrons using such an element as well as an emission/display device realized by using a cold cathode electron source having a surface profile showing an excellent field electron characteristic and showing a low electron emission threshold value, a high output level and a long service life. A dilute material gas of rare gas such as argon and/or helium, hydrogen or a mixture gas thereof is used. An electron emission element substrate (4) is held to a temperature level between room temperature and 1,300° C. in an atmosphere where boron source material gas and nitride source material gas are introduced to 0.0001 to 100 volume % relative to the dilute material gas under pressure of 0.

Abstract: Based on designs concerning boron nitride thin-films each including boron nitride crystals in acute-ended shapes excellent in field electron emission properties, and designs of emitters adopting such thin-films, it is aimed at appropriately controlling a distribution state of such crystals to thereby provide an emitter having an excellent efficiency and thus requiring only a lower threshold electric field for electron emission. In a design of a boron nitride thin-film emitter comprising crystals that are each represented by a general formula BN, that each include sp3 bonded boron nitride, sp2 bonded boron nitride, or a mixture thereof, and that each exhibit an acute-ended shape excellent in field electron emission property; there is controlled an angle of a substrate relative to a reaction gas flow upon deposition of the emitter from a vapor phase, thereby controlling a distribution state of the crystals over a surface of the thin-film.

Abstract: The object of the present invention is to provide a material excellent in field electron emission which can withstand the high intensity of electric field, allows the enhanced emission of electrons resulting in a high density of current, and does not degrade during long use. The solving means consists of providing a membrane body of sp3-bonded boron nitride excellent in field electron emission obtained by a method comprising the steps of introducing a reactive gas including a boron source and a nitrogen source into a reaction system; adjusting the temperature of a substrate in the reaction chamber to fall between room temperature to 1300° C.; radiating a UV beam onto the substrate with or without the concomitant existence of plasma; and forming via vapor-phase reaction a membrane on the substrate in which a surface texture allowing excellent field electron emission is formed in a self-organized manner.

Abstract: The present invention provides a sp3-bonded boron nitride, represented by a general formula BN, having a hexagonal 5H or 6H polytypic form and having a property of emitting light in ultraviolet region. Its producing method comprises: introducing reaction mixed gas containing boron and nitrogen being diluted with dilution gas into a reaction chamber; and irradiating a surface of a substrate placed in the chamber, a growing surface on the substrate, and a growing spacing region about the growing surface with ultraviolet light to cause gas phase reaction, thereby generating, depositing, or growing the boron nitride on the substrate.

Abstract: A method of making hard boron nitride by a plasma CVD method employing beam irradiation comprising the steps of: introducing a boron source gas and a nitrogen source gas into a plasma generated by employing a working gas selected from the group consisted of helium, hydrogen and a mixture of these under pressure of 0.01 through 100 torr, said boron source gas and said nitrogen source gas are provided with volumetric percent of 0.01 through 10% with respect to the working gas; transmitting activating innoculations formed in the plasma to a substrate of which temperature is maintained at 300.degree. through 1100.degree. C; converting the activating innoculations into precursor activating innoculations necessary for forming and growing a hard boron nitride film on the substrate by irradiating an ultraviolet beam to the activation innoculations on the substrate; and accumulating the hard boron nitride on the substrate.

Abstract: A method for preparing diamond or diamond-like carbon, which comprises exciting carbon by decomposing, evaporating and dissociating an organic compound or a carbon material in a combustion flame of at least 600.degree. C. of a hydrocarbon, hydrogen or a mixture thereof and oxygen gas or air, mixing thereto hydrogen in an amount of at least one time by volume the amount of carbon, and maintaining the mixture at a temperature of from 600.degree. to 1,700.degree. C. to precipitate diamond or diamond-like carbon.

Abstract: A method for synthesizing diamond, which comprises:(a) generating a plasma by electric discharge in a gas selected from the group consisting of a hydrocarbon gas, hydrogen gas, an inert gas and a mixture thereof,(b) decomposing a carbon source by the plasma to form plasma gas containing carbon ions or carbon radicals,(c) effecting adiabatic expansion of the plasma gas to precipitate diamond.

Abstract: A process for producing a powder material of perovskite or its solid solution represented by the formula:ABO.sub.3wherein A is one or more metal elements coordinated with 12 oxygen atoms, and B is one or more metal elements coordinated with 6 oxygen atoms, which comprises contacting an aqueous or alcohol solution of either component A or component B with a precipitating solution to form precipitates, then adding an aqueous or alcohol solution of the other component to form precipitates, and drying the precipitates, followed by calcining at a temperature of from 400.degree. to 1200.degree. C.

Abstract: A process for producing a translucent .beta.-sialon sintered product, which comprises mixing fine powders of silicon nitride and aluminum nitride having a high purity of at least 99% and a particle size of at most 200 microns and fine powders of aluminum oxide and silicon oxide having a high purity of at least 99% in such a proportion as to form .beta.-sialon of the formula Si.sub.6-z Al.sub.z O.sub.z N.sub.8-z where z is from 1 to 4.2, and hot-pressing the mixture in a nitrogen atmosphere at a temperature of from 1500.degree. to 1850.degree. C. under pressure of from 10 to 1500 kg/cm.sup.2.