Abstract: In a plate microlens of the invention, wherein gradient index lenses each having an optical axis along a normal to a surface of a transparent base and a refractive index profile gradually changing along a direction of the optical axis and a direction perpendicular thereto are formed integrally in the transparent base; a ratio d/a (where d is a thickness of the gradient index lens on the optical axis and 2a is a diameter of the gradient index lens on a surface of the transparent base) falls within a range of 0.46 to 0.78.

Abstract: A method for manufacturing a resin impregnated cloth bearing surface wherein the resin impregnated cloth is deaerated to reduce air bubbles in the finished bearing.

Abstract: A remote control unit which is simple in structure and free from the possibility of disconnection and has a stabilized illumination function. The remote control unit comprises a body case having a recess and having a plurality of push-button switches disposed thereon, and a door mounted for pivotal opening and closing motion on the body case and having a plurality of push-buttons thereon in an opposing relationship to the push-button switches so that, when the door is closed, they are each operated by operation of a corresponding one of the push-buttons. The body case has a rising portion having a light admitting hole perforated in a side wall thereof adjacent the recess, and a light emitting element is accommodated in the rising portion.

Abstract: An image fiber preform for use in an image fiber according to the present invention includes a plurality of optical fiber strands, each optical fiber strand including a silica glass core which contains a dopant for increasing a refractive index of the core and a silica glass cladding surrounding the silica glass core, the silica glass cladding containing a fluorine dopant for decreasing a refractive index of the cladding, the cladding having an outer peripheral surface, and a quartz tube in which the optical fibers are closely arranged, wherein the cladding has a concentration of the fluorine dopant which decreases radially outward toward the outer peripheral surface of the cladding. in the present invention, an image fiber prepared from the image fiber preform and fabrication processes for the image fiber preform and the image fiber are provided.

Abstract: A chain includes a plurality of identical link elements each including a main body part with a cantilevered connecting part integrally formed at one end thereof. The connecting part includes an enlarged rounded head portion and a narrower neck portion extending between the head portion and the main body part. The main body part has a rounded recess and a narrow slot formed in a first surface thereof. The slot adjoins an end of the recess opposite the connecting element. The slot extends from the recess to adjoin a side surface of the main body. Confining sections extend from the surface of the main body adjacent the slot so as to overlie opposite sides of the recess. The recess, slot and confining sections together define an opening in the first surface which has substantially the same shape as the connecting element.

Abstract: The temperature of a casting die is controlled in a low-pressure casting process for pressurizing the surface of molten metal stored in a closed container to fill the molten metal in a die cavity defined in the casting die. The temperature of the casting die is detected by a temperature sensor, and compared with a preset reference die temperature range. The amount of cooling water to be supplied to the casting die is controlled based on the result of the comparison. When the detected temperature of the casting die falls in the preset reference die temperature range, the molten metal starts to be filled in the die cavity.

Abstract: In a plate microlens of the invention wherein gradient index lenses each having an optical axis along a normal to a surface of a transparent base and a refractive index profile gradually changing along a direction of the optical axis and a direction perpendicular thereto are formed integrally in the transparent base, a ratio d/a (where d is a thickness of the gradient index lens on the optical axis and 2a is a diameter of the gradient index lens on a surface of the transparent base) falls within a range of 0.46 to 0.78.

Abstract: There is disclosed a data transmitting and receiving circuit extremely advantageous when applied to a key telephone system. The data transmitting circuit comprises a voltage dividing circuit for dividing a power supply voltage to apply the divided voltage to one end of a primary winding of a transformer, and a driver circuit comprising a pair of transistors connected in series between the power supply and a common potential terminal, the node of the transistors being connected to the other end of the primary winding of the transformer. When data signal is transmitted, the data transmitting circuit is operative to complementarily turn and off the pair of transistors in accordance with the data signal. In contrast, when data is not transmitted, the data transmitting circuit is operative to cut off both the transistors. Thus, the data transmitting circuit can eliminate the possibility that a DC voltage on which a data signal to be transmitted is superimposed undesirably changes.

Abstract: A tuning control apparatus of a receiver having an electronic tuner comprises a tuning voltage generating circuit including a window comparator, a charge pump and a low-pass filter. An S curve signal is applied to the window comparator to make a search controlled by means of a voltage synthesizer system using the S curve signal until the receipt of a broadcasting signal. If an optimum tuning point is established through the search control, the local oscillation frequency at that time is counted to provide frequency division ratio data. A phase-locked loop is operated as a function of the frequency division ratio data on the occasion of the above described optimum tuning point, whereby reception of the broadcasting signal is continued. Preferably, an automatic frequency control operation is performed before the phase-locked loop is operated.

Abstract: A ladder-type signal attenuator comprises a ladder network (50) storing a ladder resistor circuit of a plurality of stages (n-1) each having an input resistor (2R) and an output resistor (R) and a ladder portion of the final stage (n) having an input resistor (8) and an output resistor (7) and coupled to the ladder resistor circuit. The resistance value (RB) of the input resistor (8) of the ladder portion of the final stage is different from 2R and/or the resistance value (RA) of the output resistor (7) is different from R. A bias voltage (Vb) or an analog input signal (Sin) is selectively applied to a corresponding signal input terminal of the ladder circuit (50) by means of switches (S.sub.1 to S.sub.n) in response to control data (b.sub.1 to b.sub.n) of n bits. At least one of the resistance values of the two resistors (7, 8) of the final stage ladder portion is changed as a function of the state "0" or "1" of the final bit (b.sub.