摘要:
A single crystal material is filled in a crucible, and the whole of the single crystal material is melted to contain doping impurities. A solid layer coagulated upward from the bottom of the crucible is rendered to coexist with a melted layer over the solid layer. The solid layer is melted from the upper side thereof while pulling the single crystal from the melted layer. The ratio by weight between the solid layer and the single crystal material at the start of pulling is adjusted, together with the ratio by weight between the grown single crystal and the melting solid layer. The single crystal is thus grown while changing the volume of the melted layer.
摘要:
An apparatus for growing a single crystal having a crucible, two heaters arranged at the outside of the crucible and along the vertical direction, a heat shield placed at the outside of the heaters, a radiation shield for shielding the single crystal from the radiation heat, and an upper heat shield for preventing the upward heat, transfer of the heaters. In the apparatus, a melted layer and solid layer of raw material are formed in the upper and lower portions of the crucible, respectively. While melting the solid layer, the single crystal is pulled up. The lower portion of the heat shield is thinner than the upper portion. The ratio of the height to the diameter of the crucible is 0.85 or more. The melting amount of the solid layer is controlled in the pulling process according to the non-segregation condition in the variable-thickness melted layer method. The oxygen concentration of the pulled single crystal is controlled in the pulling process by adjusting the rotation speed and rotation direction of the crucible.
摘要:
An electromagnetic stirrer of linear induction motor type for a continuous casting machine, whose coils are arranged to differ a distance between poles of theeven function components of the travelling wave current distribution with respect to the center thereof from that of the odd function components so that a larger electromagnetic force is generated, thereby eliminating the internal defects, such as macro-segregation or center porosity, and improving quality of the ingot. Also, the electromagnetic stirrer, even when attached to a small-sized mold or a mold of small aspect ratio, demonstrates the sufficient effect.
摘要:
In an automatic molding apparatus, a Doppler speed meter is used to detect the rising speed of molten metal within a mold, and a nozzle stopper attached to a ladle in which the molten metal is contained is actuated in response to a difference between a detected speed signal and a speed pattern signal to control the opening of the nozzle of the ladle whereby the rising speed of the molten metal fed from the ladle to the mold through the nozzle can be controlled in accordance with an optimum molding velocity pattern.
摘要:
A gate controlling circuit for a thyristor converter having a forward/reverse bias voltage detecting circuit connected between the anode and the cathode of one of a plurality of serially connected thyristors in a thyristor arm of the converter for determining whether the thyristor is forward or reverse biased. The output of the forward/reverse bias voltage detector is utilized to control the gate control signals supplied to the thyristors in the thyristor arm.
摘要:
A gate controlling circuit for a thyristor converter having an inverse bias voltage detecting circuit which detects the inverse bias voltage across a thyristor and is connected between the anode and cathode of serially connected thyristors in a thyristor valve. A gate signal to all of the thyristors is supplied when the output of the inverse bias voltage detecting circuit drops or becomes zero after all of the thyristors are turned off.
摘要:
In repairing a blast furnace wall by injecting and solidifying a refractory material on the inside wall of the furnace from outside the furnace, a line consisting of metallic coaxial lines or metallic parallel lines insulated from each other is embedded in the refractory material and the variation of the length of this line is measured through an electric signal to detect the remaining thickness of the injected and solidified refractory material in the furnace wall part.By such detection, the damage of the repaired part of the blast furnace can be known with the lapse of time.
摘要:
In a controller, for use in an electric motor, which self-contains a current control system, a conducting portion of a feedback element from a current detector up to a summing point, and a conducting portion of a forward element from the summing point for the current control up to a gate terminal of each of switching devices are mounted in a power module to be hermetically encapsulated without being exposed to the external ambient atmosphere. The distributed processing is executed in the two portions, i.e., a current control loop, and a position control unit, a velocity control unit and an interface processing unit other than the current control loop. Therefore, the current control loop including the current feedback portion is constituted by another sub-microprocessor to be mounted together with the associated devices in a power module which is molded with resin such as epoxy resin.
摘要:
A thyristor valve circuit protected having an arrester to protect it from an overvoltage. The circuit includes a voltage detector for detecting a forward voltage level applied to the thyristor valve and generating a signal sVp when the detected voltage level exceeds a predetermined voltage which is set lower than the protection level of the arrester, and a circuit for generating a gate pulse applied to the thyristor valve in response to the signal sVp* from the voltage detector. The gate pulse generating circuit permits the gate pulse to be applied to the thyristor only when the condition of the presence of conduction command signal PHS and forward voltage signal FV, and the absence of output signal sVp* of the voltage detector, is satisfied.
摘要:
An arrester is provided including series connected first and second nonlinear resistance elements and a by-pass circuit. The by-pass circuit is connected in parallel with the second nonlinear resistance element and short-circuits the second nonlinear resistance element only when a voltage of a predetermined polarity is applied to the second nonlinear resistance element. An semiconductor circuit arrangement with a protection device is also provided, where the arrester is used for protecting a semiconductor device.