Abstract: A hemispherical Luneberg dielectric lens including a hemispherical center layer having a hemispherical outer surface, and a plurality of hemispherical dome-shaped layers each having concentric hemispherical inner and outer surfaces, the outer surfaces of the center layer and dome-shaped layers having different diameters and the inner surfaces of said dome-shaped layers having different diameters. The center layer and dome-shaped layers are successively concentrically fitted into one another and integrated into a hemispherical shape. The center layer is a foam molding of ceramic-containing thermoplastic resin expanded beads, while each of said dome-shaped layers is a foam molding of thermoplastic resin expanded beads containing 0 to 80% by weight of a ceramic. The ceramic content per unit volume of the center and dome-shaped layers decreases from the center layer to the outermost dome-shaped layer, and the standard deviation of the apparent density of each of the center and dome-shaped layers is 0.

Abstract: A radio wave lens antenna device including a semispherical Luneburg lens and a radio wave reflection plate. The radio wave lens antenna device prevents the signal reception sensitivity from being lowered in rain or snow. The radio wave lens antenna device includes a semispherical Luneburg lens 1, a radio wave reflection plate 2 that is larger than the diameter of the lens, an antenna element 3, and a holder 4 that holds the antenna element. The radio wave reflection plate 2 is arranged in an erected state. An ice-snow-water resistant means, which includes a first cover 5 and a second cover 6, prevents rain, snow, and ice from collecting and running off the Luneburg lens.

Abstract: A hemispherical Luneberg dielectric lens including a hemispherical center layer having a hemispherical outer surface, and a plurality of hemispherical dome-shaped layers each having concentric hemispherical inner and outer surfaces, the outer surfaces of the center layer and dome-shaped layers having different diameters and the inner surfaces of said dome-shaped layers having different diameters. The center layer and dome-shaped layers are successively concentrically fitted into one another and integrated into a hemispherical shape. The center layer is a foam molding of ceramic-containing thermoplastic resin expanded beads, while each of said dome-shaped layers is a foam molding of thermoplastic resin expanded beads containing 0 to 80% by weight of a ceramic. The ceramic content per unit volume of the center and dome-shaped layers decreases from the center layer to the outermost dome-shaped layer, and the standard deviation of the apparent density of each of the center and dome-shaped layers is 0.

Abstract: An expanded polypropylene bead for forming a dielectric material, including a polypropylene resin containing a ceramic in an amount of from 10 to 80 wt %, having an apparent density of from 0.03 to 1.7 g/cm3, having an intrinsic endothermic peak specific to the polypropylene resin on a DSC curve obtained by a differential scanning calorimetry, and also an endothermic peak at a higher temperature side of the intrinsic endothermic peak, and in that a caloritic value of the endothermic peak at the higher temperature side represents from 2 to 35% of a caloritic value of the peaks of the entire endothermic curve.

Abstract: A hair brush comprises a brush main body, bristles vertically provided on the upper surface of the brush main body and an immersion member provided on the upper surface of the brush main body and immersed with a liquid substance to be coated to hair. As the immersion member, mentioned are a porous member in a form of a rod, a net formed by non-woven fabric or knitted fabric of porous fiber, or a member in a form of a plate formed by porous rubber.

Abstract: A resin molded product is provided comprising a membrane having at least one opening formed therethrough. The resin molded product includes a molded body having a pair of first and second portions joined respectively to opposite sides of the membrane, the molded body having at least one connective portion interconnecting the pair of first and second portions and disposed in the opening. The membrane is either of a nonporous construction or a porous construction having a pore size of not more than 100 .mu.m. In addition, a method of producing the resin molded product is provided. The resin molded product of the invention is suited for an air vent device, a filter, a diaphragm device, or the like.

Abstract: Polymer particles composed of particles of a polymer (I) consisting of 96 to 100% by weight of at least one ethylenically unsaturated monomer and 4 to 0% by weight of at least one .alpha.,.beta.-ethylenically unsaturated carboxylic acid, and a (co-)polymer (II) comprising 100 to 10% by weight of a conjugated diolefin which is localized on the surface layer of the particles of the polymer (I) at a (I)/(II) weight ratio of 100/5-100/90. The localized polymer part of the polymer particles is very active, and the polymer particles are easy to modify with a monomer having any functional group, and hence are elemental materials having a high function and being utilizable for various purposes.

Abstract: A process for producing an electrostatic recording material which comprises kneading a hydrophobic pigment having a critical surface tension of 50 dynes/cm or less with an aqueous dispersion of a copolymer consisting of (I) 10 to 50% by weight of methacrylic acid, (II) 5 to 50% by weight of a alkenyl aromatic compound and (III) 30 to 85 % by weight of at least one member selected from the group consisting of conjugated diolefins, alkyl acrylates and alkyl methacrylates; having a glass transition temperature (Tg) of 40.degree. C or less; and having an intrinsic viscosity [.eta.] of 0.1 to 1.0 dl/g as measured in tetrahydrofuran at 25.degree.