Abstract: A method and a device for the composition of an MR image with respiration-controlled recording of the spin echoes. The phase coding gradient of an MR equipment is stepped as a function of a motion phase of the respiratory motion once per respiration cycle. With a constant phase coding gradient several scans, possibly EKG-triggered, are then recorded within the respiration cycle. The spin echo signals recorded for each scan are stored in a first memory. In a second memory, the amplitude of the respiratory motion at the respective scan moment is stored. Then a comparison of all stored amplitude of the respiratory motion with a reference value R is made. For the composition of the MR image only that scan per respiration cycle is used for which the respective amplitude of the respiratory motion fulfills a given criterion with respect to the reference value R.

Abstract: Dyeings with reactive dyes on cellulose fiber materials are after-treated with an aqueous solution of a condensate which is obtainable by reacting (a) bisbenzylpiperzine with (b) ethylene chloride, an epihalohydrin, propylene chloride, 1,3-dichloro-2-hydroxypropane, bisepoxybutane or 1,4-dichlorobutane or a mixture of these, in a molar ratio of from 1:0.5 to 1:1.1, or by reacting (c) piperazine, bis-1,4-aminopropylpiperazine, 1-aminoethylpiperazine, 2-hydroxyethylpiperazine or 1-methylpiperazine, or a mixture of these, with a compound according to (b) in a molar ratio of from 1:0.5 to 1:1.1 and benzylating the condensate, the benzylation being carried out using 0.15-1.0 mole of benzyl chloride per equivalent of nitrogen in component (c). The cellulose fiber materials after-treated in this manner possess very good wetfastness.

Abstract: The disclosure relates to nuclear spin tomography equipment in which means (22, 24) are provided for the control of the acquisition of the Fourier rows of the measurement matrix as a function of a respiration signal. The equipment includes a Fourier row counter (25) which influences a circuit (26) that controls the measurement signal acquisition. In a first embodiment of the invention the measurement signal acquisition is always released for all rows outside a predetermined region, but is a function of the respiration phase signal inside this region. The predetermined row region may comprise approximately 10% of all rows to be measured and should lie symmetrically about the center of the matrix. A further reduction of the measuring time is realized, according to another embodiment of the invention, by dispensing altogether with measurement in the row edge region of the matrix.

Abstract: .beta.-N-aziridinopropionates of relatively high boiling alcohols or polyalcohols are prepared by transesterifying a .beta.-N-aziridinopropionate of a lower alcohol of 1 to 4 carbon atoms with a relatively high boiling alcohol or polyalcohol by a process in which the transesterification is carried out in the presence of, as a transesterification catalyst, a titanium(IV) or tin(IV) compound which is soluble in an organic medium.

Abstract: A phase locked loop control system, in particular for use for synchronizing the operation of a carriage drive motor and a main drive motor in a photocopier, uses a digital frequency- and phase-comparator and relies on the output pulses, used to power the slaved motor, being shaped so that each positive-going d.c. drive pulse is followed by a negative-going d.c. braking pulse of smaller amplitude, to provide positive registration of the slaved motor with the pulsed driving signal.

Abstract: A photocopier scanning system has a scanning member (which may be the scanning lamp, a scanning mirror, a scanning slit, or a document carrier) on a scanning system powered by a d.c. drive motor synchronized to the rotation of the a.c. main drive motor for the other components of the photocopier. A variable programmer using a phase locked loop control circuit including pulse encoders slaved to the motors maintains strict synchronization between the scanning drive motor and the main drive motor with an appropriate proportionality dependent upon the image magnification/reduction ratio of the photocopier. The optical system may include a movable zoom lens element which gives infinitely variable selection of the magnification/reduction ratio, and which can readily be connected to the programmer to achieve an infinitely variable proportionality between the speeds of the scanning drive motor and the main drive motor to suit any such magnification/reduction ratio.

Abstract: In the purification of an ammonium fluoride solution containing silicic acid by adding iron (III) ions and precipitating the iron (III) ions at a pH above 8.5 and a concentration of free ammonia in the solution of more than about 1% by weight, the silicic acid being carried with the iron (III) ion precipitate, the improvement which comprises adding the iron (III) ions to the ammonium fluoride solution at a temperature below about 30.degree. C. and, before removal of the precipitate, to the solution a salt of at least one of the alkali metals, alkaline earth metals, zinc, aluminum and lead in such quantity that the solution becomes saturated with such salt.

Abstract: In the production of a synthetic fluorspar of low silicon dioxide content wherein hexafluosilicic acid is added in an amount ranging from slightly below up to about stoichiometric amount to an aqueous calcium carbonate suspension at a temperature from about 0.degree. to 40.degree. C., and the calcium fluoride formed is separated off from the dilute silica sol and optionally washed out, the improvement which comprises reacting the calcium carbonate with the hexafluosilicic acid in such a way that the pH-value of the fully reacted solution amounts to between about 3.6 and 4.6, and adding a fast-reacting proton acceptor to the reaction mixture immediately before separation of the calcium fluoride in amount sufficient to raise the pH to about 5.0 to 6.4, preferably about 5.8 to 6.2. Suitable proton acceptors include the alkali metal and ammonium hydroxides carbonates and hydrogen carbonates or alkaline earth metal hydroxide.

Abstract: A roller to be used in apparatus for wet treatment of photographic material comprises a hollow metallic core and two inserts with coupling shafts provided therein. A coat of chemically resistant thermoplastic material is applied around and sealingly surrounds the core to protect it from the corrosive action of media used in the wet treatment process. The outer surface of the thus coated roller is thereupon machined to a high-quality finish.

Abstract: In the production of an ammonium fluoride solution by precipitating hexafluosilicic acid from its solution with ammonia and from the resulting suspension separating off the silicon dioxide precipitated, the improvement which comprises thoroughly mixing the hexafluosilicic acid solution and ammonia at a temperature of about 40.degree. to 90.degree. C, in such proportions that the suspension obtained contains at least 1% of free ammonia and at most 22% of ammonium fluoride, the average residence time of the reactants in the precipitation zone being at least 4 minutes. Advantageously, the silicon dioxide is separated off from the suspension obtained without previous cooling, the resulting ammonium fluoride filtrate is left standing for at least 30 minutes to permit flocculation of silicon dioxide contained therein and the flocculated silicon dioxide is separated off.

Abstract: A roller to be used in apparatus for wet treatment of photographic material comprises a hollow metallic core and two inserts with coupling shafts provided therein. A coat of chemically resistant thermoplastic material is applied around and sealingly surrounds the core to protect it from the corrosive action of media used in the wet treatment process. The outer surface of the thus coated roller is thereupon machined to a high-quality finish.