Abstract: A reactor with a reaction chamber (14), which is produced for example by etching or other micro-mechanical production processes. An agitating device (20) is formed for example by an electrical field generator (18), which acts on electrical charge carriers (21) of the sample fluid, and consequently leads to circulation or mixing of the sample fluid. As an alternative, a magnetic field generator which acts on magnetic particles in the sample fluid may also be used. The reactor permits the extensive miniaturization of test reactors for bioprocesses, since circulation of the fluid to achieve a quasi steady-state bioprocess is possible the agitating devices even under extremely confined spatial conditions.

Abstract: N-Phenyl-1-naphthylamine can be prepared by reaction of aniline and 1-naphthylamine in the liquid phase at 100-400.degree. C. under normal pressure, a catalyst mixture comprising boron and fluorine being employed. Such catalyst mixtures can be obtained, for example, by reaction of hydrogen fluoride, boric acid and aniline and/or 1-naphthylamine. The catalyst is recovered and can be employed again. The reaction can be carried out discontinuously or continuously.

Abstract: N-phenyl-1-naphthylamine can be prepared by reacting aniline and 1-naphthylamine in the liquid phase at 100-400.degree. C. at a reaction pressure which is higher than atmospheric pressure. Boron and fluorine-containing catalysts, mono or polysulfonic acids, iodine, PCl.sub.3, PCl.sub.5, or POCl.sub.3, for example, may be used as catalysts.

Abstract: A pressure difference sensor having a semiconductor measuring diaphragm clamped between two bearing parts of insulating material thereby forming two inner chambers is described. Each of the bearing parts holds a flat electrode on its inside. An internal, pressurized, equalization chamber is provided in the clamping region of the pressure difference sensor and extends into both bearing parts around the inner chambers. The equalization chamber compensates for static pressure influences on the accuracy of the measurement of the sensor. A method for producing the sensor is also described.

Abstract: Aminobiphenyl (ABP) can be separated off from diphenylamine (DPA) by treating the DPA to be purified at elevated temperature with a substance in which oxygen is bonded by a double bond to a C atom, an N atom or another O atom and then separating off the DPA from the treated mixture.

Abstract: The invention relates to a process for making an oblique-sided recess in a substrate in which areas of the surface of the substrate corresponding to the recess to be made are covered with an etching mask which is not attacked by an isotropic etching liquid, whereupon an isotropic etching is effected. In order to be able to make oblique sides of very slight slope with such a process, a layer (4) which is removable by the isotropic etching liquid is applied to the surface areas (3) of the substrate (2) before the application of the etching mask (5).

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.