Abstract: Liquid crystal material containing at least one dyestuff of the formula ##STR1## in which A=the radical of an azo dyestuff,X=O or NH,R' and R"=H or C.sub.1 -C.sub.4 -alkyl, it being posible for the radicals ##STR2## to be identical or different, but these radicals preferably being --CH.sub.2 -radicals,Y=optionally substituted phenyl or optionally substituted naphthyl andn=2, 3 or 4,and new azo dyestuffs which come under the formula I.

Abstract: A light-collecting system, which contains a coumarin derivative of the formula ##STR1## in which T denotes O or NR.sub.4,R.sub.4 represents hydrogen, optionally substituted aryl, cycloalkyl or aralkyl,R.sub.1 denotes a carbocyclic or heterocyclic 5 or 6 membered ring bonded via a C.atom, or a 5 or 6 membered heterocyclic ring which is bonded via a N atom and is rotationally asymmetrical to an axis placed through the coumarin/N-heterocyclic bond, the 5 or 6 membered rings may carry non-ionic substituents and for an optionally substituted benzene ring or naphthalene ring to be fused to the said rings;X signifies ##STR2## or --OR.sub.2 ', R.sub.2 represents hydrogen, alkyl, cycloalkyl, aralkyl or aryl, hydrocarbon radicals may be substituted, andR.sub.3, in addition to having the definitions given for R.sub.2, also signifies a radical of the formulaeR.sub.6 --(X).sub.n --CO-- or R.sub.7 --(X).sub.n --SO.sub.2 --R.sub.6 and R.sub.

Abstract: Dyestuffs of the formula ##STR1## in which Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4 designate hydrogen, halogen, nitro, amino, alkylamino, arylamino, cycloalkylamino, aralkylamino, alkylthio, arylthio, cycloalkylthio, aralkylthio or hydroxyl, it being possible for the hydrocarbon radicals to be sustituted, with the proviso that(a) at least one of the substituents Y.sub.1, Y.sub.2, Y.sub.3 or Y.sub.4 does not denote hydrogen,(b) a maximum of two of the substituents Y.sub.1, Y.sub.2, Y.sub.3 and Y.sub.4 designate halogen and either(c.sub.1) X.sub.1, X.sub.3 represent halogen, --R.sub.1, --OR.sub.1 or --SR.sub.1, R.sub.1 denoting optionally substituted alkyl, it being possible for the alkyl chain to be substituted by an oxygen atom or several non-adjacent oxygen atoms, optionally substituted aryl, optionally substituted cycloalkyl, optionally substituted aralkyl or an optionally substituted heterocyclic radical and X.sub.2 designating hydrogen, or(c.sub.2) X.sub.1, X.sub.

Abstract: Optically monoaxial film of plastic which is coated with a product formed by hardening a mixture of a prepolymer, containing at least two (meth)acryloyl groups, and a (meth)acrylic acid ester of a monohydric or polyhydric aliphatic alcohol and/or an aliphatic vinyl compound, and the use of this film in liquid crystal visual displays.

Abstract: An optically virtually isotropic plastic film, in particular for use in liquid crystal displays, can be produced by a method in which first an optically uniaxial birefringent plastic film is produced by casting or extrusion, and then irreversible molecular reorientation is produced in layers of the film close to the surface by heating or by immersion in a solvent or swelling agent. This reoriented structure is retained after cooling or drying of the film, and results in the birefringence (anisotropy) initially present being eliminated or compensated.

Abstract: Liquid-crystal material containing an azo dyestuff of the formula ##STR1## in which X denotes H, --CN, --CF.sub.3, halogen, --OCF.sub.3, --COOR.sub.7, --OR.sub.7, --SR.sub.7, --NR.sub.7 R.sub.8 or A--N.dbd.N--,L and M denote an optionally substituted 1,4-phenylene radical or an optionally substituted 1,4-naphthylene radical,A and B denote the radical of a coupling component,R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 denote hydrogen, halogen, trifluoromethyl, nitro, alkyl, alkoxy, alkylcarbonyl, alkylthio or alkoxycarbonyl, andm and n denote 0, 1 or 2, subject to the proviso that m+n is 1 or 2,it being also possible forR.sub.7 and R.sub.8 to denote hydrogen or alkyl, cycloalkyl, aryl and aralkyl which is optionally interrupted by 1-3 non-adjacent O atoms, it being possible for the hydrocarbon radicals mentioned for R.sub.7 and R.sub.8 to be substituted and, in the case of --NR.sub.7 R.sub.

Abstract: Anthraquinone dyestuffs of the formula ##STR1## in which R.sub.1 represents alkyl, aralkyl, --CO--X-alkyl, --CO-- X-aralkyl, --CO--X-aryl, --O-alkyl, --O-aralkyl, --O-- aryl, --CN, --NO.sub.2, --CF.sub.3, halogen or a heterocyclic radical andR.sub.2 represents H or R.sub.1,X representing O, S, NH or a direct bond andY.sub.1, Y.sub.2, Y.sub.3 and Y.sub.4 denoting hydrogen, --NH.sub.2, --OH, halogen, --NO.sub.2 or an arylmercapto group and at least one of the substituents Y.sub.1 -Y.sub.4 representing an arylmercapto group,it being also possible for the alkyl, aryl, aralkyl and heterocyclic radicals mentioned for R.sub.1 and Y.sub.1 -Y.sub.4 to be substituted, the preparation and use thereof, and dichroic material containing these anthraquinone dyestuffs.

Abstract: A light-collecting system, characterized in that it contains a coumarin derivative of the formula ##STR1## in which T denotes O or NR.sub.4, in whichR.sub.4 represents hydrogen, optionally substituted aryl, optionally substituted cycloalkyl or optionally substituted aralkyl,R.sub.1 denotes a carbocyclic or heterocyclic 5-membered or 6-membered ring bonded via a C atom, or a 5-membered or 6-membered heterocyclic ring which is bonded via a N atom and is rotationally asymmetrical to an axis placed through the coumarin/N-heterocyclic bond, it being possible for the said 5-membered or 6-membered rings to carry non-ionic substituents and for an optionally substituted benzene ring or an optionally substituted naphthalene ring to be fused to the said rings;X signifies ##STR2## or --OR.sub.2 ', in which R.sub.2 represents hydrogen, alkyl, cycloalkyl, aralkyl or aryl, it being possible for the said hydrocarbon radicals to be substituted, and R.sub.3, in addition to having the definitions given for R.sub.

Abstract: Birefringence-free arrangement of plastic foils, characterized in that two plastic foils having a single principal optical axis, said optical axis lying within the plane of the plastic foil, are arranged parallel behind each other so that the optical axes of both plastic foils are forming an angle of 90.degree..+-.7.degree. and the material of the foils with regard to its optical properties and the thickness of the foils being selected in such a manner that the optical path differences .DELTA.n.sub.1 D.sub.1 for the light waves which are associated with the two main refraction indices within the first plastic foil is approximately equal to the optical path difference .DELTA.n.sub.2 d.sub.2 of the second plastic foil, .DELTA.n.sub.1, .DELTA.n.sub.2, being the difference of the main refraction indices in the first and second foil, respectively, and d.sub.1, d.sub.

Abstract: The firmly adhesive metallization, in particular partial metallization, of the surface of semiconductors is possible, without pickling, by carrying out the activation with organometallic compounds of metals of the I and VIII Secondary Groups of the Periodic Table of Elements, then reducing in a conventional manner and metallization without current.

Abstract: Light-collecting system, characterized in that it contains a coumarin derivative of the formula ##STR1## in which T designates O or NR.sub.4, wherein R.sub.4 represents hydrogen, optionally substituted alkyl or optionally substituted aryl;R.sub.1 designates a carbocyclic or heterocyclic, oxygen-free 5-membered or 6-membered ring which is linked via a C atom or a 5-membered or 6-membered heterocyclic ring which is linked via an N atom and which rotates unsymmetrically about an axis passing through the coumarin-N-heterocyclic ring linkage, it being possible for the 5-membered or 6-membered rings mentioned to carry non-ionic substituents and for an optionally substituted benzene ring or an optionally substituted naphthalene ring to be fused onto them;R.sub.2 designates hydrogen, alkyl, cycloalkyl, aralkyl or aryl, it being possible for the hydrocarbon radicals mentioned to be substituted, and R.sub.3 designates hydrogen, alkyl, cycloalkyl, aralkyl, aryl or a --OR.sub.5, --SO.sub.2 R.sub.5, --SO.sub.2 NHR.sub.

Abstract: Liquid-crystalline material containing an azo dyestuff of the formula ##STR1## in which A and B are radicals of coupling components in particular of the benzene, naphthalene and pyrazole series andR.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are hydrogen, halogen, trifluoromethyl, nitro, alkyl, alkoxy, alkylthio, alkylcarbonyl or alkoxycarbonyl with the proviso that at least one of the radicals R.sub.1 -R.sub.6 is different from hydrogen and at least two designate hydrogen.

Abstract: A method for making a light-collector of a transparent plastic and a fluorescent dye, wherein the monomers forming transparent plastics are mass-prepolymerized in the presence of radical catalysts and the fluorescent dye is added before, during or at the end of prepolymerization, and then polymerizing the mixture to completion by adding another catalyst, also at pressures of from 2 to 20 bars and at temperatures of from 50.degree. to 160.degree. C., and the use of the light-collector thus produced in combination with photovoltaic elements, preferably based on Ga/As or Si.

Abstract: Light-collecting system, characterized in that it contains a dyestuff of the formula ##STR1## in which Hal designates identical or different halogen atoms from the series comprising fluorine, chlorine and bromine,R.sub.1 and R.sub.2 designate hydrogen or optionally substituted C.sub.1 -C.sub.18 -alkyl and n designates 4-5,and new dyestuffs of the formula I which in a 0.5-2 mM solution in path lengths of 10 cm display an increase in transmission from 0 to >95% with a change in the wavelength of 25-120 nm.

Abstract: The firmly adhesive metallization, in particular partial metallization, of the surface of semiconductors is possible, without pickling, by carrying out the activation with organometallic compounds of metals of the IB and VIIIB Groups of the Periodic Table of Elements, then reducing in a conventional manner and metallizing without current.

Abstract: Liquid crystal material containing a disazo dyestuff of formula ##STR1## in which R.sub.1 designates alkyl, aralkyl, cycloalkyl, aryl, alkylsulphonyl, aralkylsulphonyl, cycloalkylsulphonyl, arylsulphonyl, acyl or a R--NH--CO-- or R--O--CO-- group,in whichR represents alkyl, aralkyl, cycloalkyl or aryl, it being possible for the radicals mentioned for R.sub.1 to be substituted, andn is 0 or 1,Y designates --O--,R.sub.2 has one of the meanings given above for R.sub.1, if n=1, or is hydrogen, if n=0, andR.sub.3, R.sub.4, R.sub.5 and R.sub.6 designate hydrogen, optionally substituted alkyl, alkoxy, halogen or cyano.

Abstract: Brighteners of the formula ##STR1## wherein R denotes hydrogen or an aliphatic or aromatic radical and Ar denotes an aromatic carbocyclic or heterocyclic radical, can be purified from colored by-products by dissolving in mineral acids and crystallized out by cooling without reduction in yield.

Abstract: Laser light of different wavelength can be produced by exciting sparingly water soluble fluorescent compounds of which the .alpha..alpha. m value is less than 0,300 and of which the molecular symmetry is either of symmetry group C.sub.s or of a higher symmetry group than this, the fluorophor having to form a rigid system if the compound belongs to symmetry group C.sub.s, the compounds being present in concentrations of between 10.sup..sup.-1 and 10.sup..sup.-5 mol/l in organic solvents.

Abstract: 2-Aryl-v-triazoles are obtained by reacting .alpha.-oximinoaryl-hydrazones of the formula ##EQU1## IN WHICH Ar represents an aromatic-carbocyclic or aromatic-heterocyclic radical, R.sub.1 denotes alkyl, aryl or nitro, R.sub.2 denotes hydrogen, alkyl or aryl and n denotes the numbers 1 or 2 with at least 2 equivalents of an isocyanate or carbamic acid halide or with at least 1 equivalent of a pyrocarbonic acid ester.

Abstract: Vic-triazoles are obtained in almost quantitative yield and high purity when .alpha.-oximino-arylhydrazones of the formula ##EQU1## IN WHICH Ar represents an aromatic-carbocyclic or aromatic heterocyclic radical, R.sub.1 denotes an aliphatic or aromatic radical, R.sub.2 denotes hydrogen or an aliphatic or aromatic radical and n denotes the numbers 1 or 2, are reacted with at least 1 mol equivalent of a cyclising agent in the presence of heavy metals or of their ions.