Abstract: In pulse welding apparatus of arc welding or short-circuit transfer type arc welding in which a pulse discharge created on the tip of a wire electrode is utilized to perform welding, when a molten droplet produced on the tip of wire electrode is late to separate from the wire due to variations of welding conditions and external disturbances. The wire-supplying speed at which the wire is supplied to the weld zone changes. This causes undercut, i.e., a defect in welding bead-shape that presents adverse effect to welding quality. To prevent this problem, pulse current supplied to the base metal is divided into a plurality of pulse groups and the average current reaches the maximum peak value at a predetermined time after beginning of outputting the pulses, and the group of pulse currents is of a hill-shape in its envelope in accordance with the separation phenomenon of molten droplet, and the group of pulse currents is arranged to have different pulse period, pulse width, and pulse interval.

Abstract: A pulse welding apparatus using a pulse discharge such as a pulse arc welding apparatus and a short-circuit transfer arc welding apparatus. A pulse current waveform control circuit, which controls the pulse arc current so that a desired pulse arc current is supplied to the arc welding power supply for outputting the pulse arc current to the welding load unit, is constructed such that the optimum welding operation may be performed without having to adjust circuit components and modify circuit design. The pulse current waveform control circuit is in the form of a microcomputerized digital circuit which operates under a program to provide a desired pulse arc current. A modification of the program can provide any desired pulse arc currents without changing circuits. The optimum welding current waveform parameters or a target arc length signal is learned in the first welding stage and stored into a memory.

Abstract: An apparatus for and a method of controlling a laser oscillator for use as a laser source in a machining operation or the like is disclosed. In particular, the present invention compensates for a deviation of an actual input/output characteristic of a laser oscillator from a normal (expected) input/output characteristic due to, for example, aging and the like. The present invention approximates the actual input/output characteristic and stores the characteristic as a pattern in a storage device. In response to a detection of the actual laser output and an external intensity command signal, the present invention refers to the input/output characteristic pattern thus approximated and generates an input intensity command signal for controlling the laser oscillator to accurately produce the desired laser beam intensity irrespective of the deviation between the actual input/output characteristic and the normal characteristic.

Abstract: The welding equipment according to the present invention divides the pulsed electric current fed to a base metal in the course of a welding process into a plural number of pulse groups, performing instantaneous control over the base electric current period and the base electric current value applied to each of the pulse intervals of the individual pulses within such a group of pulsed electric currents and to each of the groups of pulsed electric currents, the pulse peak value and pulse width of each pulse, and such instantaneous control over a short circuit period and an arc period in the course of performance of the short circuiting transfer arc welding process, in accordance with the detected arc length, in such a manner that an ideal target arc length is thereby achieved.

Abstract: A pulse welding apparatus using a pulse discharge such as a pulse arc welding apparatus and a short-circuit transfer arc welding apparatus. A pulse current waveform control circuit, which controls the pulse arc current so that a desired pulse arc current is supplied to the arc welding power supply for outputting the pulse arc current to the welding load unit, is constructed such that the optimum welding operation may be performed without having to adjust circuit components and modify circuit design. The pulse current waveform control circuit is in the form of a microcomputerized digital circuit which operates under a program to provide a desired pulse arc current. A modification of the program can provide any desired pulse arc currents without changing circuits. The optimum welding current waveform parameters or a target arc length signal is learned in the first welding stage and stored into a memory.

Abstract: A pulsed arc welding for carrying out arc welding or short-circuit transfer type arc welding by utilizing the pulsed discharge generated at the tip of a wire electrode. The propensity of wire electrode curvature causes irregular changes in the contact point of the wire electrode and variations in the arc length between the wire electrode tip and workpieces. Consequently, the invention detects arc voltage and current and checks the instantaneous variation in the arc length. The arc voltage value thus detected is converted to a reference arc voltage variable. Then the detected arc voltage value is compared with the reference value to compute a true arc length. A simulation arc length signal, which varies as welding proceeds, and a reference simulation welding current waveform are set, to compare the simulation arc length signal with the computed arc length signal.

Abstract: The present invention relates to a method of producing an amide which comprises subjecting a nitrile to the action of a microorganism belonging to the genus Rhodococcus and having the ability to hydrate the nitrile, and isolating the resulting amide. The microorganism is highly active to a wide variety of nitriles even at low temperatures and, in addition, the hydration reaction of nitriles has a high selectivity for the corresponding amides. Accordingly, this method ensures the production of amides in high yield without formation of by-products such as corresponding carboxylic acids.

Abstract: A multi-lumen epidural catheter includes a flexible inner tube 10 having a tip opening 12 and a surrounding flexible outer tube 11 having a pair of side openings 13 spaced upstream from the tip. An anesthetic solution may be injected through the separate flow and discharge paths defined by this structure to deaden a more elongate zone of a patient in a precisely controlled manner.