Abstract: A porous membrane of an aromatic polyimide having an enhanced permeability of a gas or liquid is produced by a process comprising the steps of(1) preparing a dope solution of 3 to 30% by weight of an aromatic polyimide in a mixed solvent of (A) 100 parts by weight of a base solvent capable of dissolving 5% by weight or more of the polymeric acid and of evaporating at 30.degree. C. to 400.degree. C. and (B) 5 to 150 parts by weight of an additional liquid not capable of dissolving 3% by weight or more of the polyamic acid and capable of evaporating at a smaller evaporating rate than that of the base solvent at the above-mentioned evaporating temperature;(2) forming a thin layer of the dope solution at 0.degree. C. to 120.degree. C.; and(3) heating the dope solution layer at 30.degree. C. to 400.degree. C. so as to evaporate off the mixed solvent and to convert the polyamic acid to the corresponding polyimide.

Abstract: An aromatic polyimide membrane having an excellent gas-separating property comprises (A) a substrate consisting of a porous membrane comprising at least one aromatic polyimide having at least 80 molar % of at least one type of recurring unit of the formula (I): ##STR1## wherein R is a tetravalent aromatic radical and R.sup.1 is a divalent aromatic radical, the porous membrane exhibiting a hydrogen gas permeability (PH.sub.2) of 1.times.10.sup.-5 to 5.times.10.sup.-1 cm.sup.3 /cm.sup.2.sec.cmHg and a ratio of hydrogen gas permeability (PH.sub.2) to carbon monoxide gas permeability (PCO) of 2 to 5; and (B) 50% or more, based on the weight of the porous membrane substrate, of a gas-separating liquid contained in the porous membrane substrate, the gas-separating liquid being substantially incapable of dissolving therein the porous membrane substrate and having a boiling point of 180.degree. C. or more.

Abstract: There are video and sound recording devices such as movie cameras or video cameras with an automatic focusing system of the type for setting a photographic lens to a position at which an object can be sharply focused in response to the signal which is representative of a distance from the camera to the object and obtained by measuring the time interval from the time when the ultrasonic waves are transmitted at a predetermined repetition frequency to the object to the time when the echo from the object is received. Such devices have a common defect that a microphone picks up impulse-like noise generated from an ultrasonic transducer especially at the start point of ultrasonic waves. To overcome this problem, the present invention provides an audible noise elimination or suppression means or a control circuit which operates in synchronism with the ultrasonic wave transmission so that an audio signal processing system attenuates the audio output signal.

Abstract: Aromatic polyimide hollow fibers having an enhanced mechanical strength are produced by a process comprising the steps of: preparing a spinning dope solution of at least one aromatic polyimide having 90 molar % or more of a recurring unit of the formula (I). ##STR1## wherein R is a divalent aromatic radical, in a phenolic solvent; converting the dope solution into at least one filamentary stream thereof; and introducing the filamentary dope solution stream into a coagulating liquid having a coagulating rate coefficient of 1.5 microns/sec for the dope solution, to provide rigid hollow filaments.

Abstract: An earth terminal for electrical equipment which is adapted to be attached to and detached from a ground pin.

Abstract: An aromatic polyimide composite membrane having an excellent gas-separating property is produced by a process comprising the steps of: coating at least one surface of a substrate consisting of an aromatic polyimide porous membrane with a solution of 0.05% to 10% by weight of an aromatic polyamic acid in a polar organic solvent, which is not capable of dissolving the polyimide porous membrane, at a temperature not exceeding 140.degree. C.; after a during drying the resultant thin coating layer of the polyamic acid solution, heating the resultant polyamic acid layer at a temperature of 150.degree. C. or more so as to convert the polyamic acid layer to the corresponding polyimide layer.

Abstract: A gas separating material having excellent heat and chemical resistance, mechanical strength and gas-separating function, comprises a gas separating layer consisting of at least one dense film having a thickness of from 0.1 to 20 microns and comprising at least one aromatic imide polymer which comprises at least 80 molar % of at least one type of recurring unit of the formula (I): ##STR1## wherein R represents a divalent aromatic radical.

Abstract: A polyimide semipermeable membrane is prepared by the process comprising the steps of:preparing a solution of a polyimide material consisting essentially of at least one aromatic polyimide comprising at least 90 molar % of at least one recurring unit of the formula (I): ##STR1## wherein R represents a divalent aromatic radical, in a solvent consisting of at least one phenol compound in the state of a liquid or melt;forming a thin layer of the polyimide solution, and;coagulating the thin layer of the polyimide solution by bringing the thin layer into contact with a coagulating liquid to form a semipermeable membrane.

Abstract: Aromatic polyimide fibers having an enhanced mechanical strength are produced by a process comprising the steps of: preparing a spinning dope solution of at least one aromatic polyimide having 90 molar % or more of a recurring unit of the formula (I): ##STR1## wherein R is a divalent aromatic radical, in a phenolic solvent; converting the dope solution into at least one filamentary stream thereof; solidifying the filamentary dope solution stream by removing the solvent therefrom to provide at least one undrawn filament, and; drawing the undrawn filament at a temperature of 20.degree. to 600.degree. C. at a draw ratio of 1.5 to 5.0.

Abstract: An assembly robot includes a quadrilateral link mechanism formed by plurality of links. Swinging or movement devices are connected to two adjacent links and are supported by a base. An assembling tool is installed at a connection of two other links opposite the moving devices.

Abstract: A parallel indexing cam structure has a locking cam and a pair of further cams which are rigidly secured to an input shaft at predetermined angular positions relative to each other, and a cam follower device is rigidly secured to an output shaft parallel to the input shaft and has a plurality of spider plates and three sets of cam follower rollers. During the dwell period, the locking cam is contacted by two rollers of one set of the cam follower rollers while the further cams are contacted by only one of the rollers of the respective remaining sets. The locking cam has a larger profile circle at the dwell position during the dwell period than the further cams, thereby blocking the rotation of the output shaft with increased accuracy and stiffness during the dwell period.

Abstract: A DC to DC converter includes a push pull oscillating circuit having a pair of active components, the anodes of which are connected to each end terminal of the primary winding of a saturable inverter transformer. A secondary winding of the saturable inverter transformer is connected to a load through which the output of the secondary winding is positively fed back to the control electrodes through the cathodes of the active components. The whole circuitry is operated by low voltage small dry cells connected between the midpoint of the primary winding and the cathodes of the active components providing high DC output to the load.