Optionally readable information disk in which the information track is situated in a radiation-cured lacquer layer comprising at least 50% by weight of a diacrylate, triacrylate or a mixture thereof and which the cured lacquer layer has a high indentation hardness.

The invention is a new family of phosphine compounds which can be used to make optically active metal coordination complex catalysts which combine high efficiency with a capability of performing rapidly (high efficiency and rapidly being established from Tables I, II and III as being greater than 75% efficiency and in times of not more than a few hours, preferably less than one hour) in water and thus avoiding solvent recovery and loss problems. The catalysts can be used in some alcoholic medium...

An optically activatable semiconductor component having at least one light-sensitive surface area containing a light-sensitive PN junction which is biased in a nonconducting direction when exposed to light, wherein in order to avoid a reduction in the inhibiting voltage of the optically activatable semiconductor component, the light-sensitive PN junction leading to the light-sensitive surface of the component is shaped such that it has a simple, preferably circular or tubular form at the light-s...

An optically isotropic device or component made of an optically isotropic polymeric material which is a blend of two completely miscible polymers which have opposite optical anisotropies. The blend has zero birefringence which is not substantially affected by processing of the blend into the optical device or component.

The compounds (R)-1,2-bis(diphenylphosphino)-3-benzyloxypropane and (R)-1-tert-butoxy-2,3-bis(diphenylphosphino)propane are precursors to new rhodium-based asymmetric reaction catalysts having the formula: ##STR1## wherein R is benzyl or tert-butyl.

An optically readable information disk which comprises a transparent substrate plate (1) of PVC or a copolymer of vinyl chloride which is provided on one side with a reflecting optical structure (2-5) and on the other side with a radiation-cured lacquer layer (6) which is transparent to the laser light (7) used.

An optically toggled bidirectional normally-on switch is provided with protection against bilateral voltage and bidirectional current surges by the inclusion of a pair of oppositely poled thyristors. One version uses a large junction-type field-effect transistor in its main path and a pair of smaller junction-type transistors in the subsidiary path. A photodiode array controls the gate voltage on each of the transistors and turns them off when illuminated. A control node in the subsidiary path i...

Optically translucent theoretically dense body of mullite is produced by pressing an amorphous mixed oxide powder composition of from about 72.5 weight % to about 76.5 weight % Al.sub.2 O.sub.3 /balance SiO.sub.2 into a compact of density of at least 1.0 g/cc, sintering the compact in oxygen or a vacuum of 0.05 torr to 1 torr producing a gas-impermeable compact, hot isostatically pressing the gas-impermeable compact to theoretical density, and with respect to compositions ranging from higher tha...

An optically compensated zoom lens particularly suited for use in a still camera. This lens system comprises positive first, negative second and positive third lens groups counting from the front of which the first and third ones are axially movable in fixedly spaced relation to each other during zooming, while the second one remains stationary together with a relay lens group that follows the third lens group, the relay lens group consisting of a negative lens with its front surface of strong d...

Neral or geranial are hydrogenated into optically active citronellal in the presence of a catalytic complex comprising a rhodium derivative and a chiral phosphine.