Abstract: To obtain a sugar-plum shaped composite particle, a reaction vessel with 300 parts by weight of water placed therein is charged with 30 parts by weight of polymethyl methacraylate resin particles of 2 ?m average particle diameter, and ultrasonic waves are applied to the mixture for 1 minute to obtain a particle dispersion liquid. Subsequently, 15 parts by weight of methyltrimethoxysilane is added to the dispersion liquid to obtain methyltrimethoxysilane hydrolyzates in the dispersion liquid. Thereafter, 10 parts by weight of 1 weight % aqueous ammonia is added thereto and agitated. One minute later, the agitation is discontinued, and the mixture is allowed to stand still for 10 hours to effect maturation. The resultant mixture is filtered and dried to obtain sugar-plum-shaped particles provided on their surfaces with polyorganosiloxane projections.

Abstract: To obtain a sugar-plum shaped composite particle, a reaction vessel with 300 parts by weight of water placed therein is charged with 30 parts by weight of polymethyl methacraylate resin particles of 2 ?m average particle diameter, and ultrasonic waves are applied to the mixture for 1 minute to obtain a particle dispersion liquid. Subsequently, 15 parts by weight of methyltrimethoxysilane is added to the dispersion liquid to obtain methyltrimethoxysilane hydrolyzates in the dispersion liquid. Thereafter, 10 parts by weight of 1 weight % aqueous ammonia is added thereto and agitated. One minute later, the agitation is discontinued, and the mixture is allowed to stand still for 10 hours to effect maturation. The resultant mixture is filtered and dried to obtain sugar-plum-shaped particles provided on their surfaces with polyorganosiloxane projections.

Abstract: To obtain a Raney catalyst for fixed bed permitting a continuous use with a high initial activity and to produce a high purity sugar-alcohol at a low cost using the same. For this object, sugar-alcohol is produced by: using the powder type Raney catalyst made by using for the hydrogenation under the hydrogen pressure a lump form Raney catalyst made by (i) the first step for melting nickel and aluminum, (ii) the second step for obtaining quenched lump alloy by quenching droplets of said melted mixture and (iii) the third step for classifying and activating said quenched lump alloy as it is or once it is broken, collecting said lump form Raney catalyst, crushing into powder and reactivating, and hydrogenating sugars under the hydrogen pressure.

Abstract: To obtain a Raney catalyst for fixed bed permitting a continuous use with a high initial activity and to produce a high purity sugar-alcohol at a low cost using the same. For this object, sugar-alcohol is produced by: using the powder type Raney catalyst made by using for the hydrogenation under the hydrogen pressure a lump form Raney catalyst made by (i) the first step for melting nickel and aluminum, (ii) the second step for obtaining quenched lump alloy by quenching droplets of said melted mixture and (iii) the third step for classifying and activating said quenched lump alloy as it is or once it is broken, collecting said lump form Raney catalyst, crushing into powder and reactivating, and hydrogenating sugars under the hydrogen pressure.

Abstract: To obtain a Raney catalyst for fixed bed permitting a continuous use with a high initial activity and to produce a high purity sugar-alcohol at a low cost using the same. For this object, sugar-alcohol is produced by: using the powder type Raney catalyst made by using for the hydrogenation under the hydrogen pressure a lump form Raney catalyst made by (i) the first step for melting nickel and aluminum, (ii) the second step for obtaining quenched lump alloy by quenching droplets of said melted mixture and (iii) the third step for classifying and activating said quenched lump alloy as it is or once it is broken, collecting said lump form Raney catalyst, crushing into powder and reactivating, and hydrogenating sugars under the hydrogen pressure.

Abstract: The vacuum chuck, which is an accessory device for holding a workpiece in machining and inspection, has a suction head made of a porous sintered particles of a thermoplastic resin, e.g., a fluorocarbon resin, preferably, bonded to the chuck base. The suction head is free from the problem of unreliableness of holding of workpieces without the danger of damaging the workpiece. The outer peripheral surfaces of the sucking head are provided with an air-impermeable layer to increase the efficiency of suction by preventing leakage of vacuum. The water-and-oil-resistance of the suction head can be improved by blending the powder of the thermoplastic resin with a powder of a thermosetting resin, e.g., epoxy resin.