Abstract: Disclosed is an ultrapure 4-methylpyrazole containing less than 0.1% pyrazole and containing less than 10 ppm each of hydrazine and nitrobenzaldehyde. The ultrapure 4-methylpyrazole is prepared by a novel process so that less than 0.01% of ethylvinyl ether is present.

Abstract: The present invention relates to a method and a device of information transfer between two circuits exchanging data via delta-sigma converters. The present invention includes coding the information in the form of at least one signal of determined frequency corresponding to an integer multiple of a frequency of the digital data samples; mixing, at a first end of a line carrying an oversampled digital signal of the converter, the signal of determined frequency; extracting from the mixture, at a second end of the line, the signal of determined frequency; and decoding the corresponding information.

Abstract: The present invention relates to a method and a device of information transfer between two circuits exchanging data via delta-sigma converters. The present invention includes coding the information in the form of at least one signal of determined frequency corresponding to an integer multiple of a frequency of the digital data samples; mixing, at a first end of a line carrying an oversampled digital signal of the converter, the signal of determined frequency; extracting from the mixture, at a second end of the line, the signal of determined frequency; and decoding the corresponding information.

Abstract: This process comprises eliminating the ammonia from a gaseous effluent of the treatment of scrubbing with a liquid essentially comprising water, regenerating the scrubbing liquid by stripping countercurrent with respect to the gas to be treated, then recycling at least most of the regenerated scrubbing liquid by putting it into thermal exchange relation with the scrubbing liquid to be regenerated.Application in the production of CO.sub.2 by the treatment of smoke with ammonia.

Abstract: The single channel measuring head has a sensor whose output signal is amplified and filtered. A converter provides sequencies of 3 pulses representing a low reference, the measured parameter and a high reference. The time-period between the first two pulses represents the parameter which is measured. The sequencies are sent to a receiver including a converter which constitutes the amplitude of the parameter.

Abstract: The transmission of digital data takes place over a network comprising a data transmission line and a control and synchronizing line connecting together a master station, alone capable of transmitting over the control line, and several slave stations. The two lines are unidirectional and looped back to the master station and the stations transmit information in phase over the two lines. For that, each slave station comprises means for extracting clock information from the signal permanently present on the control line.