Abstract: A nitrogen selective adsorbent comprises a zeolite of a faujasite crystalline structure containing Li+ and at least one of NH+ and H+ as essential cations, and has a nitrogen adsorption characteristic represented by specific correlation between the number of associated Li+ ions per unit lattice of a zeolite crystal and the amount of adsorbed nitrogen per unit lattice of the zeolite crystal. An air separation method employs the aforesaid nitrogen selective adsorbent for separation between nitrogen and oxygen by selective adsorption of nitrogen in air.

Abstract: A nitrogen selective adsorbent comprises a zeolite of a faujasite crystalline structure containing Li+ and at least one of NH+ and H+ as essential cations, and has a nitrogen adsorption characteristic represented by specific correlation between the number of associated Li+ ions per unit lattice of a zeolite crystal and the amount of adsorbed nitrogen per unit lattice of the zeolite crystal. An air separation method employs the aforesaid nitrogen selective adsorbent for separation between nitrogen and oxygen by selective adsorption of nitrogen in air.

Abstract: A nitrogen adsorbent comprising a crystalline X zeolite having a faujasite structure with an SiO2/Al2O3 ratio of less than 3.0, wherein the crystal contains at least one trivalent element of the group consisting of Fe, B and Ga and (AlO4)5− tetrahedral units thereof associated with cations. Although the adsorbent contains a designated trivalent element in the zeolite, it maintains the number of cation sites contributing to adsorption, has an excellent separation performance of nitrogen and oxygen, and exhibits excellent heat resistance. Further, when the nitrogen adsorbent of the present invention is used in such a particular manner that it adsorbs nitrogen after being heated under a vacuum, adsorption performance is improved.

Abstract: Gas sensor materials composed of carbon mixture or metal-containing carbon mixture obtained as evaporated matter by arc discharge which occurs by passing an alternating current or a direct current with electric current density of 0.8 to 3.5 A/mm.sup.2 on discharge surfaces of carbon electrodes or metal-containing carbon electrodes in an inert gas under a pressure of 0.1 to 600 torr.

Abstract: This invention relates to an apparatus wherein a vacuum chamber is divided into two spaces, the substrate heating space and the crystal growth space, so that the degree of vacuum in the substrate heating space is set lower than the pressure for the Si growth and the degree of vacuum in the crystal space is set corresponding to the pressure for Si growth to thereby grow Si based semiconductor with excellent reproducibility over a long period. Moreover, heat efficiency toward the substrate is heightened by enclosing the upside and the circumference of the heating means with the heat shielding body to cut energy cost.

Abstract: A method and an apparatus for separating a specific component gas from a mixed gas, wherein granular adsorbent is held in a sealed space in a layered state, easily adsorptive gas is adsorbed to the granular adsorbent by blowing material mixed gas into the adsorbent layers and contacting the granular adsorbent with a counter-current of material gas, and the granular adsorbent is transferred gradually out of the sealed space, and reactivated by desorbing the easily adsorptive gas from the granular adsorbent, and the reactivated granular adsorbent is returned to the inside of the sealed space to be reused. Therefore, frequent actions of opening and closing valves are unnecessary, so that it is possible to separate and produce excellent product gas with high purity.

Abstract: This invention relates to an apparatus wherein a vacuum chamber is divided into two spaces, the substrate heating space and the crystal growth space, so that the degree of vacuum in the substrate heating space is set lower than the pressure for the Si growth and the degree of vacuum in the crystal space is set corresponding to the pressure for Si growth to thereby grow Si based semiconductor with excellent reproducibility over a long period. Moreover, heat efficiency toward the substrate is heightened by enclosing the upside and the circumference of the heating means with the heat shielding body to cut energy cost.