Movable Pin Research Articles

Electron-temperature control by movable pins installed in a hollow cathode for discharge plasmas

In order to control electron energy distributions in discharge plasmas, we have developed a new hollow cathode with pins inside. With an increase in the pin length, the electron temperature is observed to decrease continuously by an order of magnitude, being accompanied by a change of local plasma structure, in weakly magnetized low-pressure Ar dc discharge plasmas.

Precision Tension Control System for VCR Using Moving Tape Guide Actuator.

We have developed a new precision tension control system which can suppress the head-impact and transient tension alternation. This system is suitable for home-use digital VCRs which require thin tape to run stably.In this system, a moving tape guide actuator is installed at the entrance side of a rotary drum, serves as a tension detector and a tension control actuator.This moving tape guide actuator consists of a swing arm type voice-coil motor and a movable pin which stays in contact with the tape.The tension control system which employs the tension detector based on the modern control theory (detection range: 1kHz) achieved the wide control band (170Hz).

A soap film model illustrating phase transitions

A two-dimensional soap film model is described in which a soap film joins three fixed pins arranged in a triangular configuration and a movable pin. The energy of the film can be expressed as a two-parameter quadratic equation. This equation is characteristic of a class of systems which exhibit phase transitions of both first-order and second-order type. Alternatively, the equation can be interpreted as representing a double-cusp catastrophe.

A method of examining stereoscopic photographs

The paper describes a method of analysing stereoscopic photographs which has been found suitable for the examination of Wilson cloud tracks. The method consists essentially in replacing the photographic plates in the cameras, illuminating them and tracing out the common image which coincides in space with the object originally photographed. A system of movable pin points is used to trace out the contour of the image, the adjustments of the cameras being kept exactly the same as when the photographs were taken. The chief advantage of the method is its simplicity - practically no computation is required and it is not necessary to know the stereoscopic angle, the magnification, etc. The method has been used by the authors to measure the ranges of secondary β-rays and in investigations on the initial directions of emission of photoelectrons, and it has been found convenient and accurate.