Abstract: A frameless and coreless porous endosseous implant comprising a porous sintered metal layer (2) having a range of relatively large pores and porous sintered metal layers having a range of relatively small pores and laminated into one body by sintering integrally with the layer on either side thereof, or a porous singered metal layer having a range of relatively small pores and porous sintered metal layers having a range of relatively large pores and laminated into one body by sintering integrally with the layer on either side thereof, whereby the three layers each permit the ingrowth and penetration out of two or more kinds out of fibrous tissue, osteoid tissue and bone tissue in the pores thereof.

Abstract: Acetylene can be polymerized into a polyacetylene by a solid-state polymerization reaction when it is compressed into a solid under a high pressure of, for example, 1 GPa or higher. The polyacetylene product is obtained in a bulky transparent form in contrast to conventional polyacetylenes in a fibrous form prepared by utilizing a Ziegler-Natta catalyst, and free from impurities because neither catalyst nor solvent is used in the reaction.

Abstract: An endosseous implant having a mesh pore structure including at least an embedding portion to be embedded in a living bone tissue, the embedding portion being a single sheet of a platelike body or a desired shape of body obtained by working the platelike body. The platelike body can be a single metal mesh sheet or a laminate of a plurality of metal mesh sheets formed into one body by mechanical bonding or by sintering, the laminate having a multiplicity of mesh pores passing through the embedding portion, whereby the embedding portion provides a mesh pore structure adapted to permit into the mesh pores the ingrowth and penetration of a fibrous tissue along out of three kinds of bone, osteoid, and fibrous tissues or not less than two tissues inclusive of the fibrous tissue.

Abstract: The fins of an aluminum heat exchanger are treated with a coating composition comprising an alkali silicate and a low-molecular-weight compound having carbonyl and are thereafter heated for drying, whereby a hydrophilic coating is formed over the surfaces of the fins.

Abstract: A hearing aid is made up of an automatic filter circuit for transmitting an input signal in a predetermined characteristic, and a low frequency component detecting circuit for detecting the low frequency component of the input signal, to change the characteristic of the automatic filter circuit according to the detection level, the cut-off frequency of the automatic filter circuit being changed according to the output control signal of the low frequency component detecting circuit.

Abstract: An interchangeable lens assembly for a camera is formed with a bayonet coupling affixed to the lens barrel with both being rotatable relative to an adapter shell. Upon attachment of the lens assembly to a camera housing, a detent pin is retracted from a fitted hole found in a radial flange of the adapter shell and the lens barrel is thereby rendered rotatable together with the bayonet coupling with reference to both the adapter shell and the camera housing while the adapter shell is held stationary relative to the camera housing during mounting and dismounting of the lens assembly.

Abstract: A method of designing a telephoto type zoom lens having a convergent front member movable for focusing and capable of providing focusing down to as short an object distance as 6.5 times the longest focal length to achieve good stabilization of correction of spherical aberration on adjustment of the other aberrations within predetermined limits throughout the extended focusing range even when zooming is effected to the telephoto settings. This is accomplished by means of the formula:F(Ao, Lo) = .phi..sup.3 h.sup.4 Ao(1-.lambda..sup.4 -4a.beta.+6a.sup.2 .beta..sup.2) + 4.phi..sup.2 h.sup.2 Lo(-.beta.+3a.beta..sup.2) - .beta.(.alpha.').sup.2 + .beta..sup.2 {2.phi.(3+Po) + 3.alpha.'.alpha.'}In the case of the telephoto type zoom lens comprising, in addition to such front component, a divergent second component or variator, a convergent or divergent third component or compensator and a convergent fourth component or relay lens,-0.25.ltoreq.F(Ao, Lo).ltoreq.0.25is found as acceptable.

Abstract: An interchangeable lens assembly for a camera including a lens barrel having a diaphragm mechanism mounted therewith, a bayonet coupling mechanism fixed on the lens barrel and adapted to be brought into engagement with a complementary coupling mechanism on the camera for releasably mounting the lens assembly in operative position on the camera, an adapter shell mounted on the lens barrel in rotative relationship relative thereto for establishing predetermined relative positioning between the interchangeable lens assembly and the camera, and a retainer mechanism adapted to be interposed between the adapter shell and the camera for retaining the adapter shell in fixed rotative position relative to the camera during mounting and dismounting of the interchangeable lens assembly. The lens assembly also includes a diaphragm presetting mechanism for transmitting signals representative of a diaphragm aperture between the lens assembly and the camera.

Abstract: A device adapted for the purpose of enabling the use of presently available interchangeable photographic lenses in recently developed digitalized single lens reflex camera systems. This device is constructed in the form of an adaptor attachable to and detachable from the body of an interchangeable lens mount and capable, upon attachment to a conventional interchangeable lens, of providing information representing the full open F number of the interchangeable lens in the form of a coded digital signal. This signal is applied to a digitalized camera body associated therewith and provided, for example, with an inputting device adapted to receive the full open F number of the interchangeable lens as coded digital signal.

Abstract: A zoom lens comprising, as viewed from the side of a photographing object, a first lens group, which is positive and is provided for focusing, including a positive lens formed by joining a negative lens and a positive lens together and a positive meniscus lens; a second lens group, which is negative and is provided for variation, including a negative lens and another negative lens formed by joining a negative lens and a positive lens together; a third lens group, which is provided for compensation, including a positive lens formed by joining a negative lens and a positive lens together; a fourth lens group which is positive and is provided for image formation; and a fifth lens group which is weakly negative, the third lens group drawing a concave locus toward the object side as the second lens group moves in the direction of an optical axis. The fourth lens group is composed of two positive meniscus lenses closedly adjacent to each other and a biconcave lens disposed apart from these meniscus lenses.