Abstract: Herein disclosed is a device for measuring a displacement of a movable member relative to a fixed member by putting the electromagnetic induction into practical use. The device comprises a first coil having first and second coil sections which are coaxially aligned along a common axis, a second coil arranged to establish a magnetic coupling with the first coil and extending along the common axis, and a short circuit ring arranged to establish a magnetic coupling with the first and second coils and movable relative to the same. The winding density of each of the first and second coil sections is gradually decreased from the outside end to the inside end thereof, and the winding density of the second coil is substantially even throughout the length of the same.

Abstract: A three-dimensional shape measuring apparatus includes a projection device having a projecting plane witha grating pattern formed therein and a light source for illuminating, through the projection plane, an object of interest located at an arbitrary position in the same three-dimensional coordinate system as that of the projection device, an observation device located in the same three-dimensional coordinate sysem as that of the object and having an observation plane and a specific point located between the observation plane and the object. In the apparatus, the grating pattern in the projection plane is projected on a surface of the object to form a projected grating pattern thereon when the light source is turned on, the grating pattern projected on the object is observed in the observation plane.

Abstract: Herein disclosed is a device for measuring a displacement of a movable member relative to a fixed member by putting the electromagnetic induction into practical use. The device comprises a first coil having first and second coil sections which are coaxially aligned along a common axis, a second coil arranged to establish a magnetic coupling with the first coil and extending along the common axis, and a short circuit ring arranged to establish a magnetic coupling with the first and second coils and movable relative to the same. The winding density of each of the first and second coil sections is gradually decreased from the outside end to the inside end thereof, and the winding density of the second coil is substantially even throughout the length of the same.

Abstract: A shape measuring apparatus includes a first light source for illuminating a solid object in a proper place through a first slide, a second light source for illuminating the object through a second slide and an observation plane permitting the surface of the object to be observed through a focal point. Each of the first and second slides, contains slit lines. When the first and second light sources are lighted, the slit lines of the first and second slide are projected, in an intersecting pattern, on the surface of the object. A projection grating is formed on the surface of the object and is observed, as a projection grating, in the observation plane.

Abstract: A differential amplifier formed of MISFETs includes a differential amplification stage and a pair of cascade amplification stages which receive outputs from the differential amplification stage. In each of the cascade amplification stages, an amplifying MISFET which receives an input signal at its source has a channel conductivity of opposite type to that of the differential input MISFETs of the differential amplification stage. The differential amplifier with this construction has good frequency characteristics. Since the pair of cascade amplification stages make the currents taken from a pair of outputs from the differential amplification stage equal to each other, the operating balance of the differential amplification stage is not affected.

Abstract: Synthetic resin emulsion is effectively recovered from waste water containing said synthetic resin emulsion by a method which comprises; adding coagulant to waste water containing synthetic resin emulsion to coagulate said synthetic resin emulsion, separating the coagulation of said synthetic resin emulsion from said waste water, and redispersing said separated coagulation in medium such as water or another synthetic resin emulsion by using water soluble polymer as dispersant.