Abstract: A polytetrafluoroethylene porous film obtainable by applying an aqueous dispersion of emulsion polymerized polytetrafluoroethylene particles having an average minor particle size of 1 to 500 nm and an average aspect ratio of at least 10 on a substrate, drying the applied dispersion and optionally sintering the dried polytetrafluoroethylene particles on the substrate to obtain the polytetrafluoroethylene porous film, which has a uniform thin thickness.

Abstract: Provided is a resin composition for sliding movement, comprising (a) 90-30% by weight of a thermotropic liquid crystalline polymer which is a (co)polymer containing at least a monomer unit represented by the following formula and (b) 10-70% by weight of a spherical glassy carbon characterized by a particle fracture surface having a glassy luster and exhibiting a loss in weight of not more than 5% by weight when held in air at 350.degree. C.

Abstract: Polytetrafluoroethylene powder having an average particle size of 1 to 30 .mu.m and a specific surface area of 2 to 6 m.sup.2 /g is prepared by heating unsintered polytetrafluoroethylene powder having a melting point of 313.degree. to 330.degree. C. at a temperature in a range from a temperature 70.degree. C. lower than the melting point to a temperature lower than the melting point and comminuting the heated powder.

Abstract: A golf practice device comprising a mat with at least two sensors arranged therein in the direction of a swing orbit of a head of a golf club. A swing time substantially from a start of a back swing to a point of an impact with a golf ball is calculated in response to signals output by the sensors, and the result is indicated so that a golfer can observe same and thus achieve a stable swing. It is possible to distinguish an address motion and an actual swing before impact by adapting a special combination of the outputs of the two sensors.

Abstract: A light-weight and tough muffler having a high noise deadening effect characterized in that the outer barrel (I) of the muffler is made of a thermotropic liquid crystal polymer. An example of said polymer is a wholly polyester having monomer units represented by general formula (I): ##STR1## This polymer may contain 10 to 60 wt. % of inorganic additives such as glass fibers or carbon fibers.

Abstract: A control valve, in which a valve body opening and closing a valve mouth is driven by a strain force of a piezostack, characterized in that an upper fixed portion of said piezostack is supported by a ring-like tapered surface or a spherical surface and a lower movable portion of the piezostack is combined with a valve body through a spherical bearing.The strain output can be surely transmitted to said valve body by holding the piezostack so that no movement other than a strain resulting from the application of voltage may be produced.

Abstract: A height adjusting device for adjusting the height of a pickup, comprises a support mechanism for supporting the pickup on the carriage in a manner that a position of the pickup along the axis of rotation of the turntable of the optical disc player is adjustable and an adjusting device for driving the support mechanism to adjust the position of the pickup. The adjusting device generates a height position signal indicative of the position of the pickup and the support mechanism is driven in response to the magnitude of the height position signal only when the magnitude of the height position signal is greater than a predetermined level. According to the other aspect of the invention, a compensated height position signal is generated by superimposing a compensating signal indicative of the position of the optical system of the pickup relative to the housing of the pickup on the height position signal, and the support mechanism is driven in response to the magnitude of the compensated height position signal.

Abstract: An aqueous dispersion comprising composite colloidal particles having an average particle size of 0.05 to 1.0 micrometer each of which comprises a core made of a copolymer comprising 99-100% by weight of tetrafluoroethylene and 0 to 1 % by weight of a fluorine-containing olefin which is copolymerizable with tetrafluoroethylene and a shell made of a polymer having a glass transition temperature of at least 50.degree. C. which comprises(a) 60 to 100% by mole of at least one .alpha.-substituted acrylate of the formula:CH.sub.2 .dbd.CXCOOR.sub.f (I)wherein X is a methyl group, a fluorine atom or a trifluoromethyl group, and R.sub.

Abstract: A fluorovinyl ether of the formula:XCH.sub.2 CF.sub.2 CF.sub.2 --(OCH.sub.2 CF.sub.2 CF.sub.2).sub.m --(OCFYCF.sub.2).sub.n --OCF.dbd.CF.sub.2 (I)wherein X is a hydrogen atom or a halogen atom (e.g. fluorine, chlorine, bromine and iodine); Y is a fluorine atom or a trifluoromethyl group; m is an integer of 0 to 5; and n is 0, 1 or 2, which can modify a polymer of at least one ethylenically unsaturated compound.

Abstract: Modified PTFE fine powder which comprises primary particles having an average particle size of 0.1 to 0.6 .mu.m and contains 0.01 to 0.15% by weight, based on the total weight of the particles, of at least one olefinically unsaturated compound selected from the group consisting of a fluoroalkyl vinyl ether of the formula:X(CF.sub.2).sub.n OCF.dbd.CF.sub.2 (I)wherein X is a hydrogen atom, a fluorine atom or a chlorine atom and n is an integer of 1 to 6, and a fluoroalkyl vinyl ether of the formula:C.sub.3 F.sub.7 (OCF.sub.2 CF.sub.2 CF.sub.2).sub.m [OCF(CF.sub.3)CF.sub.2 ].sub.l OCF.dbd.CF.sub.2 (II)wherein m is an integer of 0 to 2 and l is an integer of 0 to 2 mainly in core parts of the particles and 0.04 to 0.25% by weight, based on the total weight of the particles, of chlorotrifluoroethylene in shell parts, which has good paste extrudability and heat stability.

Abstract: An aqueous dispersion comprising an aqueous medium and colloidal particles of a fluorine-containing copolymer having an average particle size of about 0.05 to 1.0 um dispersed therein, each colloidal particle being constructed with a core portion made of a polymer comprising about 99 to 100% by weight of units of tetrafluoroethylene and about 0 to 1% by weight of units of at least one other fluoroolefin and a shell portion made of a polymer comprising about 50 to 97% by weight of units of tetrafluoroethylene and about 3 to 50% by weight of units of chlorotrifluoroethylene, the amount of chlorotrifluoroethylene in the core and shell portions being from about 2.5 to 25% by weight based on the entire amount of the core and shell portions.

Abstract: A valve body which is driven by a valve body-driving portion constructed from a piezoelectric stack to open and close a valve mouth. The piezoelectric stack consists of piezoelectric disc elements having a thickness of 0.1 to 0.5 mm and a diameter of 10 to 50 mm, whose upper surface and lower surface are both plated, and thin metallic plates each having a thickness of 0.05 to 0.2 mm and being high in electric conductance, are alternately laminated one between the piezoelectric elements by one (the number of piezoelectric elements laminated is 100 to 200). Every other one of the thin metallic plates are connected to a positive polar lead and the remaining plates are connected to a negative polar lead, and a voltage-applying lead wire is connected with each of the lead wires.

Abstract: A time base correction circuit for correcting time base error commonly present in two or more signals having components in different frequency bands, wherein the number of stages of the respective clock response delay elements is reduced. A single clock generator supplies clock pulse signals for plural clock response delay elements. The clock generator output is connected directly to the clock response delay element to which is applied the input signal having the highest frequency component. Frequency dividers are connected between the clock generator and each of the other clock response delay elements.

Abstract: An apparatus for compensation of time axis deviations of a reproduced composite video signal, based on detection of phase deviations of the horizontal sync and color burst components respectively of that video signal, incorporates a summing circuit in which are added a signal indicating the phase deviation of the horizontal sync component and a low-frequency signal component of the output from a phase comparator which detects phase deviations of the color burst component, with the sum output signal from the summing circuit being applied to control the delay produced by a variable delay line through which the video signal is transferred. The output signal from the latter phase comparator controls phase modulation by a phase modulator which receives the video signal from the delay line output.

Abstract: An aqueous PTFE dispersion containing colloidal PTFE particles having a comparatively large average particle size is prepared by polymerizing TFE in an aqueous medium at a temperature of from 10.degree. to 100.degree. C. in the presence of a fluorine-containing dispersant and a water soluble polymerization initiator, in which, after the initiation of the polymerization and before consumption of 30% of TFE to be polymerized, TFE is polymerized at a pressure not higher than 4 Kg/cm.sup.2 for a period in which at least 1 g of TFE per liter of the aqueous medium is consumed, and then the rest of TFE is polymerized at a pressure of from 6 to 30 Kg/cm.sup.2, which dispersion does not contain any metal ion that reduces interfacial potential of the colloidal particle.

Abstract: A thermopile type detector which is constituted by an electrically insulating film, a thermopile supported on the film, a semiconductor substrate supporting the film, and a temperature sensing element on the surface of the substrate on which the film is supported and in the neighborhood of a cold junction of the thermopile. The temperature on the substrate immediately adjacent a cold junction of the thermopile can be measured for use in compensating the output of the thermopile for the changes in temperature of the cold junction. The temperature sensing element can be a semiconductor material such as a diode or a transistor forming a semiconductor with the substrate.

Abstract: In a motor vehicle having a hatchback door of glass which is hinged at its upper portion to the vehicle body to be swingable upwardly and downwardly to open and close a door opening formed in the vehicle body, the hatchback door is equipped at its lower end portion with an elongate strip of flexible elastic material which extends along the entire of the lower portion in a manner to cover at least the extreme edge of the lower portion.

Abstract: A resilient member having preselected properties is disposed on a bolt securing an elastomeric bumper to a vehicle body bumper stay for biasing the elastomeric member against the bumper stay with a force which remains within preselected limits despite expansion and creeping of the elastomeric bumper. The hole in the bumper stay and the hole in the elastomeric bumper through which the bolt is disposed are of different diameters, or one is elongate to allow the bolt and the elastomeric bumper to move in a plane normal to the axis of the bolt.

Abstract: A process for preparing polytetrafluoroethylene fine powder by polymerization of tetrafluoroethylene in an aqueous medium comprising a water-soluble polymerization initiator and a non-telogenic surfactant capable of keeping colloidal polytetrafluoroethylene particles at a sufficiently stable state, characterized in that the polymerization is carried out at a temperature of 55.degree. to 120.degree. C., and a polymerization retarder chosen from aromatic hydroxy compounds, aromatic amino compounds and quinone compounds which has a water-solubility of not less than 2.5.times.10.sup.-6 mol/liter at 25.degree. C. and does not have any reinitiation ability after its addition or chain transfer to a free radical in the polymerization system is incorporated in the aqueous medium in an amount of 0.

Abstract: Polytetrafluoroethylene fine powders which have an average molecular weight of not less than 5,000,000, preferably not less than 5,500,000, an amorphous index of not more than 0.1, preferably not more than 0.09, a number average primary particle size of 0.1 to 0.4 micron, preferably 0.15 to 0.38 micron, and a sharp endothermic peak at a temperature between 343.degree. C. and 350.degree. C. on the melting diagram by a differential scanning calorimeter, said sharp peak having an endothermic ratio of not more than 0.3, preferably not more than 0.27, and a half value width of the endothermic peak of not more than 8 degrees, preferably not more than 6 degrees, and a process for producing the polytetrafluoroethylene fine powders. The polytetrafluoroethylene fine powders have an excellent stretchability and are useful for electric wire coating, small diameter tubes, large diameter tubes, sealing tapes and the like.