Abstract: There is proposed a nitrogen treating method for nitrogen compounds which is capable of removing nitrogen compounds efficiently and achieving a downsizing of equipment and a decrease in costs. The nitrogen treating method is a method for treating nitrogen compounds in for-treatment water by an electrochemical process, wherein as a metal material which constitutes a cathode, a conductive material containing or covered with an element in the group Ib or IIb of the periodic table is used.

Abstract: A container packed with a mixture of powders classified respectively into two or at least three particle-size distribution groups which are different in average particle size, the powders comprising a hydrogen absorbing alloy singly or the combination of such an alloy and a substance not absorbing hydrogen. The mixture is at least 0.03 to not greater than 0.50 in the ratio d.sub.2 /d.sub.1 wherein d.sub.1 is the average particle size of the powder having the particle-size distribution of the largest average particle size, and d.sub.2 is the average particle size of the powder having the particle-size distribution of the second largest average particle size. The weight ratio of the powder to the total weight of the powders is greater when that powder has a particle-size distribution of larger average particle size.

Abstract: A hydrogen absorbing alloy-packed container packed with a mixture of powders classified respectively into at least two particle-size distribution groups, each of which is different in mean particle size, the powders comprising a hydrogen absorbing alloy singly or the combination of a hydrogen absorbing alloy and a substance not absorbing hydrogen, the mixture having a ratio r.sub.N+1 /r.sub.N, wherein r.sub.N is the mean particle size of the powder having a particle-size distribution of the Nth largest mean particle size, N being an integer of not smaller than 1, and r.sub.N+1 is the mean particle size of the powder having a particle-size distribution of the (N+1)th largest mean particle size, of at least 0.03 to not greater than 0.50. The alloy powders can be selected from the group consisting of lanthanum-nickel, mischmetal-nickel, iron titanium and titanium manganese.

Abstract: A container packed with a mixture of powders classified respectively into two or at least three particle-size distribution groups which are different in average particle size, the powders comprising a hydrogen absorbing alloy singly or the combination of such an alloy and a substance not absorbing hydrogen. The mixture is at least 0.03 to not greater than 0.50 in the ratio d.sub.2 /d.sub.1 wherein d.sub.1 is the average particle size of the powder having the particle-size distribution of the largest average particle size, and d.sub.2 is the average particle size of the powder having the particle-size distribution of the second largest average particle size. The weight ratio of the powder to the total weight of the powders is greater when that powder has a particle-size distribution of larger average particle size.

Abstract: A shaped body of hydrogen absorbing alloy prepared by pressing a mixture of a hydrogen absorbing alloy powder A having a first particle-size distribution, a hydrogen absorbing alloy powder B having a second particle-size distribution and a binder C, the powder A being larger than the powder B in mean particle size, the mixture being at least 0.03 to not gerater than 0.50 in the mean particle size ratio r.sub.B /r.sub.A of the powder B to the powder A wherein r.sub.A and r.sub.B are the mean particle sizes of the respective powders A and B. The hydrogen absorbing alloy of the powder B is higher than the hydrogen absorbing alloy of the powder A in the rate of progress of pulverization resulting from absorption and desorption of hydrogen.

Abstract: A shaped body of hydrogen absorbing alloy prepared by pressing a mixture of a hydrogen absorbing alloy powder A having a first particle-size distribution, a hydrogen absorbing alloy powder B having a second particle-size distribution and a binder C. The powder A is larger than the powder B in mean particle size. The mixture has a mean particle size ratio r.sub.B /r.sub.A of the powder B to the powder A, wherein r.sub.A and r.sub.B are the mean particle sizes of the respective powders A and B of at least 0.03 to not greater than 0.50. The hydrogen absorbing alloy of the powder B has a higher rate of progress of pulverization resulting from absorption and desorption of hydrogen than the hydrogen absorbing alloy of the powder A.

Abstract: The invention relates to an apparatus for measuring the gas absorbing and/or desorbing characteristics of a substance having a property to absorb a gas. The apparatus comprises a sample container for containing the substance, a gas storage connected to the sample container for storing the gas until a predetermined pressure is reached, a gas supply source for supplying the gas to the gas storage, a first valve provided on a line connecting the gas supply source to the gas storage, a second valve provided on the line between the first valve and the gas storage, and a third valve provided on a gas discharge line connected to the line between the first and second valves, the first to third valves being each a two-position valve having an open position and a closed position, the valves defining a region thereby surrounded and serving as a preliminary storage for temporarily holding the gas when the gas is supplied or discharged.

Abstract: A fuel cell system for directly converting chemical energy of a fuel into electric energy electrochemically. A fuel cell has a cathode and an anode. A main hydrogen absorbing alloy supplies a hydrogen gas to the anode of the fuel cell during steady-state operation of the system. An auxiliary hydrogen absorbing alloy originally having a higher hydrogen gas absorbing/desorbing equilibrium pressure than the main hydrogen absorbing alloy at an equal temperature supplies a hydrogen gas to the anode until the equilibrium pressure of the main hydrogen absorbing alloy, which is supplied an exhaust gas from the fuel cell is equal to a hydrogen gas absorbing/desorbing equilibrium pressure of the auxiliary hydrogen absorbing alloy, the auxiliary hydrogen absorbing alloy receiving the hydrogen gas from the main hydrogen absorbing alloy during steady-state operation.

Abstract: In order to make a thermal utilization system operable in a stable and efficient condition regardless the variation of the operating heat source used, the system is provided with three hydrogen absorbing alloys having different pressure-temperature characteristics, wherein absorption/desorption of hydrogen gas is performed in two steps, i.e. the hydrogen gas desorbed from a first alloy is absorbed by a second alloy at a predetermined pressure, and is absorbed by the third alloy at a higher pressure after it is desorbed from the second alloy in a case when the temperature of the operating heat source is low, while the hydrogen gas desorbed from the first alloy is directly transported from the first alloy to the third alloy to be absorbed there when the temperature of the operating heat source is high.

Abstract: A refrigerating and/or heating device of the contact type utilizing the endothermic and exothermic reactions of a hydrogen absorbing alloy comprises a contact member (16) in the form of a closed container (18) having a contact surface (17) and packed with a hydrogen absorbing alloy (19), a handle member (21) in the form of a closed container (22) packed with another hydrogen absorbing alloy (23), and a gas pipe (25) interconnecting the two members and having a valve (26).