Abstract: A blade driving device for use in cameras of the present invention includes a base plate having an exposure aperture, an ND filter blade that is supported rotatably around a supporting shaft on the base plate and is moved to a position withdrawn from the exposure aperture and a position facing the exposure aperture, and an electromagnetic actuator that drives the ND filter blade. This electromagnetic actuator includes a frame member joined to the base plate, a rotor which has a drive pin for exerting a driving force and rotates within a predetermined angle range with one end of which being supported to the frame member and the other end of which being supported to the base plate, and an exciting coil wound around the frame member and the base plate. Therefore, the structure of the electromagnetic actuator for driving a shutter blade, a diaphragm blade, an ND filter blade or the like can be simplified and reduced in cost, and this makes it possible to reduce the size and thickness of the device.

Abstract: A blade driving device for use in cameras of the present invention includes a base plate having an exposure aperture, an ND filter blade that is supported rotatably around a supporting shaft on the base plate and is moved to a position withdrawn from the exposure aperture and a position facing the exposure aperture, and an electromagnetic actuator that drives the ND filter blade. This electromagnetic actuator includes a frame member joined to the base plate, a rotor which has a drive pin for exerting a driving force and rotates within a predetermined angle range with one end of which being supported to the frame member and the other end of which being supported to the base plate, and an exciting coil wound around the frame member and the base plate. Therefore, the structure of the electromagnetic actuator for driving a shutter blade, a diaphragm blade, an ND filter blade or the like can be simplified and reduced in cost, and this makes it possible to reduce the size and thickness of the device.

Abstract: A camera blade driving device for use in a camera has a base plate having an exposure aperture; a blade supported pivotably on a supporting shaft on the base plate and capable of blocking part or all of light passing through the aperture while facing the aperture; and an electromagnetic actuator for driving the blade. The electromagnetic actuator has a frame member joined to the base plate; a rotor one end of which is supported by the frame member and an opposite end of which is supported by the base plate, the rotor having a driving pin by which a driving force is exerted onto the blade and rotating within a predetermined angular range; a magnetizing coil wound onto the frame member and the base plate; and a yoke provided outside the coil substantially coaxially with the rotor.

Abstract: A camera blade driving device for use in a camera has a base plate having an exposure aperture; a blade supported pivotably on a supporting shaft on the base plate and capable of blocking part or all of light passing through the aperture while facing the aperture; and an electromagnetic actuator for driving the blade. The electromagnetic actuator has a frame member joined to the base plate; a rotor one end of which is supported by the frame member and an opposite end of which is supported by the base plate, the rotor having a driving pin by which a driving force is exerted onto the blade and rotating within a predetermined angular range; a magnetizing coil wound onto the frame member and the base plate; and a yoke provided outside the coil substantially coaxially with the rotor.

Abstract: A method and an apparatus for producing microspherical ceramic particles such as particulate ceramic fuels for use in nuclear reactors. To produce gel particles by performing microwave heating on the small droplets of a stock solution or sol that contains uranium and other elements for nuclear reactor fuels, the small droplets are allowed to fall down through a cavity resonator using microwaves having an engineering frequency of 2.45 GHz and a quartz rod is inserted into or withdrawn out of the resonator to adjust the resonant frequency so that it will lie within the spectrum width of the microwave frequency.

Abstract: A process of preparing a fuel pellet for a nuclear reactor, comprising washing the gel particle using an organic solvent miscible with water to substitute the organic solvent for the water, removing the organic solvent, moistening again the dry gel particle, followed by press molding and sintering.

Abstract: A process and an apparatus are, herein, disclosed for producing microspheres of fissile and/or fertile materials with a high degree of sphericity from a feed solution starter containing at least one metal salt selected from among thorium, uranium and plutonium by using as a gelling medium an organic solvent that has a higher density and a greater interfacial tension with water than the feed solution and which is capable of dissolving ammonia.

Abstract: A holding device for a rotating body comprising a tubular member (1) which permits insertion therein of the rotating body, at least three support members (2) disposed along the inner periphery of the tubular member (1) so as to be movable in a substantially radial direction, and a locking arrangement (3a, 3b, 4a, 4b, 10a, 10b) capable of independently holding each of the support members (2) in a desired position. With such device, bodies which are rotatable about an axis not coaxial with the driving shaft thereof can be held in place without having any substantial influence upon their rotational shafts. Besides, it is not necessary to pay close attention to the clearance between moving members in the manufacture and use of the device, and thus the holding device is high in versatility and low in cost.

Abstract: A method and machine for machining the surface of a valve seat (3) which is required to have a very accurate alignment with respect to a guide bore of a valve guide (2).In order to be capable of machining the valve seat surface in high roundness while maintaining a high concentricity with the guide bore, a pilot member (4) is moved forward inclinably to catch a guide bore of a valve guide (2) at its front end; the pilot member is further moved forward bendably while following the guide bore; when the pilot member has reached the desired position, the posture of the pilot member in the position is firmly held; and the surface of the valve seat (3) is machined by moving edged tool members (5a) forwardly while rotating the edged tool members (5a) which are arranged coaxially with the pilot member.

Abstract: A filter medium which permits an increased amount of filtration. The filter medium can be prepared by blending 100 parts by weight of aggregate particles, 5-18 parts by weight of an inorganic bonding material having a chemical composition of about 10-50% by weight of SiO.sub.2 and about 5-20% by weight of B.sub.2 O.sub.3 and containing at least 70% by weight of a non-vitreous substance such as talc or boric acid, and about 3-15 parts by weight of a combustible substance such as wheat flour, kneading the mixture with a caking material and water, molding the kneaded mixture, drying it, and then calcining the dried mixture at a temperature not lower than about 1100.degree.C. The size and number of the air-permeable pores in the filter medium can be controlled by adjusting the amounts of the bonding material and combustible substance.