Abstract: A heat regenerating material for very low temperature use consisting of a magnetic heat regenerating material particle aggregate, wherein, among magnetic heat regenerating material particles constituting the magnetic heat regenerating material particle aggregate, a ratio of the particles being destroyed when a simple harmonic oscillation of the maximum acceleration of 300 m/s2 is added 1×106 times on the magnetic heat regenerating material particle aggregate is 1% by weight or less. Such a heat regenerating material for very low temperature use has an excellent mechanical characteristics against mechanical vibration and acceleration. A refrigerator comprises a heat regenerator constituted by packing the above described heat regenerating material for very low temperature use into a heat regenerator container. Such a refrigerator can exhibit an excellent refrigeration performance over a long term.

Abstract: A cold heat accumulating material for extremely low temperatures which comprises cold heat accumulating granular bodies in which a rate of particles, which are destroyed when a compressive force of 5 MPa is applied thereto by a mechanical strength evaluation die, out of the magnetic cold heat accumulating particles constituting the magnetic cold heat accumulating granular bodies is not than 1 wt. %. In this magnetic cold heat accumulating granular bodies, a rate of magnetic cold heat accumulating particles having more than 1.5 form factor R expressed by L2/4.pi.A, wherein L represents a circumferential length of a projected image of each magnetic cold heat accumulating particle, and A a real of the projected image, is not more than 5%. Such a cold heat accumulating material for extremely low temperatures is capable of providing excellent mechanical properties with respect to mechanical vibration with a high reproducibility.

Abstract: A thermal conductivity sheet is provided which is superior all in heat radiating characteristics (thermal conductivity) in the direction of sheet thickness, close-contact with respect to parts to be cooled, and electrical insulation. In a thermal conductivity sheet 1 in which a plurality of highly thermally conductive insulators 3 are dispersed in a matrix insulator 2, the highly thermally conductive insulators 3 are oriented obliquely or erectly in the direction of thickness of the thermal conductivity sheet 1 such that at least one end faces of the highly thermally conductive insulators 3 are exposed to a surface of the matrix insulator 2. Preferably, a ratio of the total sectional area of the highly thermally conductive insulators 3 to the total surface area of the thermal conductivity sheet 1 is set to be equal to or larger than 1%.

Abstract: The extremely low temperature cold accumulating material for use in refrigerators, for example, comprises particles containing at least one kind of rare earth element selected from a group consisting of Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb. The proportion of particles each having a particle size of 0.01 to 3 mm is 70% or greater by weight with respect to the whole particles and the proportion of particles each having a shape such that the ratio of the major diameter to the minor diameter is not greater than 5 is 70% or greater by weight with respect to the whole particles. The particles are manufactured by quenching and solidifying a molten metal containing at least one kind of rear earth element described above. The thus manufacured extremely low temperature cold accumulating material is improved in cold accumulating efficiency and is specifically improved in mechanical strength and in chemical stability.

Abstract: A nickel-metal hydride secondary cell, comprising a hydrogen absorbing alloy negative electrode accommodated in an enclosure and containing spherical hydrogen absorbing alloy particles covered with a free cooling surface and having an average particle diameter of 1 to 100 .mu.m, a non-sintered type nickel positive electrode disposed within the enclosure and positioned to face the negative electrode with a separator interposed therebetween, and an alkaline electrolyte poured in the enclosure.

Abstract: The extremely low temperature cold accumulating material for use in refrigerators, for example, comprises particles containing at least one kind of rare earth element selected from a group consisting of Y, La, Ce, Pr, Nd, Pm, Sm Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb. The proportion of particles each having a particle size of 0.01 to 3 mm is 70% or greater by weight with respect to the whole particles and the proportion of particles each having a shape such that the ratio of the major diameter to the minor diameter is not greater than 5 is 70% or greater by weight with respect to the whole particles. The particles are manufactured by quenching and solidifying a molten metal containing at least one kind of rare earth element described above. The thus manufactured extremely low temperature cold accumulating material is improved in cold accumulating efficiency and is specifically improved in mechanical strength and in chemical stability.

Abstract: A magnetic field generator comprises a permanent magnet, and pole pieces magnetically connected to the permanent magnet. The pole pieces are disposed to face each other to generate a magnetic field between them, and have a specific resistance of 20 .mu..OMEGA.-cm or more. The permanent magnet comprises a sintered alloy including iron as a main component, a rare earth element including yttrium, cobalt, and boron. The permanent magnet includes, as its main part, a strong magnetic Fe-rich phase of a tetragonal system, as well as a non-magnetic Laves phase, and preferably has a maximum energy product of 38 MGOe or more.

Abstract: A permanent-magnet material having a composition represented by the following formula;R(Co.sub.1-X-Y-.alpha.-.beta. Fe.sub.X Cu.sub.Y M.sub..alpha. M'.sub.62)A(wherein X, Y, .alpha., .beta., and A respectively represent the following numbers:0.01.ltoreq.X, 0.02.ltoreq.Y.ltoreq.0.25, 0.001.ltoreq..alpha..ltoreq.0.15,0.0001.ltoreq..beta..ltoreq.0.001, and 6.0.ltoreq.A.ltoreq.8.3,providing that the amount of Fe to be added should be less than 15% by weight, based on the total amount of the composition, and R, M, and M' respectively represent the following constituents:R: At least one element selected from the group of rare earth elements,M: At least one element selected from the group consisting of Ti, Zr, Hf, Nb, V, and Ta, andM': B or B+Si),is disclosed.

Abstract: Disclosed is a comprising a powdered alloy composed of 23 to about 29% by weight of samarium, 0.2 to about 7% by weight of titanium, 3 to about 9% by weight of copper, 10 to about 25% by weight of iron, and the balance of cobalt principally; said powdered alloy being sintered to obtain a sintered body, followed by(a) annealing the sintered body at a cooling rate of not more than 5.degree. C./min from an annealing-initiating temperature of from 600.degree. to 900.degree. C., or(b) subjecting the sintered body to a multi-stepwise aging processing initiated from a higher temperature to a lower temperature within the temperature range of from 350.degree. to 900.degree. C.The magnet is excellent in all the magnetic properties such as residual magnetic flux density, coercive force and maximum energy product, and also excellent in antioxidation property.