Abstract: The invention relates to a coating composition suitable for application to plastic surfaces. The coating composition comprises, as essential components, 100 parts by weight of a chlorotrifluoroethylene based copolymer having hydroxyl group as a functional group, a curing agent for the copolymer such as a polyisocyanate, 0.5-30 parts by weight of an acrylic or methacrylic polymer which serves as an adhesion improving component, and an organic solvent. Usually the composition contains an ultraviolet absorber and another light stabilizer. For example, on a polycarbonate article this composition provides a durable coating film without marring the transparency and healthiness of the polycarbonate substrate. By the addition of a pigment the coating is modified into a paint composition which is particularly useful for repairing a bake finished paint film formed by using a polyvinylidene based paint.

Abstract: A display source emits light. A first hologram receives the light from the display source and diffracts the received light. The light from the display source is applied to the first hologram at an incident angle A1 and moves from the first hologram at an outgoing angle B1. A second hologram receives the light from the first hologram and diffractively reflects the received light. The light diffractively reflected by the second hologram forms an image of the display source in viewer's field of view. The light from the first hologram is applied to the second hologram at an incident angle A2 and moves from the second hologram at an outgoing angle B2. The first and second holograms are nonparallel to remove a ghost image of the display source which would result from at least one of surface reflections at the first and second holograms. The first hologram has an angle .theta. relative to the second hologram. The angles A1, B1, A2, B2, and .theta.

Abstract: A columnar vortex generator is set in a duct communicating with an intake pipe of an engine, to extend across the airflow in the duct. A vortex sensor is arranged in a downstream surface of the vortex generator. The sensor generates a signal corresponding to the frequency of Karman vortexes generated at the downstream side of the vortex generator. A turbulence generator for generating a turbulent flow in that part of intake air flowing against the vortex generator is set at the upstream side of the vortex generator. The vortex generator consists of stationary and movable units. The movable unit is moved in accordance with elongation/contraction of a bellows so as to vary the typical dimension D of the surface of the vortex generator against which air flows.

Abstract: A mass flowmeter has a vortex generator for shedding a Karman vortex street downstream of the vortex generator positioned inside a duct for guiding a fluid. The vortex generator comprises a stationary member and a movable member which is displaceable in relation to the stationary member. The movable member is displaced by the expanding or contracting of bellows in response to changes in pressure and temperature of the fluid to thereby vary the characteristic dimension of the vortex generator. The Karman vortex shedding frequency of the vortex generator is measured by a heat-wire type sensor.