Abstract: A method of seismic exploration employing a plurality of emission sources and at least one receiver, arranged in a common plane, in which the sources emit signals into the medium to be explored, which are received after reflection by the receiver, the emission times anda received signals being recorded and correlated to yield required information, and in which the relative emission times of the pulse sources is determined by a predetermined program. Apparatus for carrying out this method is also proposed.

Abstract: The liquid phase dimerization of diolefins is effected by maintaining the diolefins in solution in an inert solvent in contact with a catalyst which is the reaction product of a transition metal carbonyl and a compound which is a transition metal halide or pseudo halide coordinated with groups capable of furnishing three electrons. The dimerization of butadiene to vinyl-4-cyclohexene and cyclooctadiene and the dimerization of C.sub.4 cracked fractions into vinyl-4-cyclohexene are preferred reactions.

Abstract: The present invention describes a process of producing block copolymers from monomers of different types by polymerization in two successive steps. The first step consists in polymerizing monomers of a first type by means of coordinated anionic catalysts comprising organo-metallic compounds of a metal of the Group IA, IIA, IIIA, or mixtures thereof of Mendeleev's Periodic Table of Elements, associated with a transition metal compound of Group IV to VIII and the second step comprises polymerizing a second type of monomer in the presence of the polymer formed in the first step and in the presence of free radical catalysts, wherein 0.01 to 100 moles of an adjuvant per mole of transition metal compound is added to the reaction medium of the first step and this adjuvant consists of a compound MY.sub.

Abstract: The present invention relates to a new manner of grafting various organic groups or polymers; it is concerned particularly with the grafting of vinyl, acryl, vinylidene or other chains on polymers of olefines, diolefines, aromatic vinyl compounds and similar compounds; a new catalytic system is used for effecting such a grafting, wherein a deactivated polymer is brought into contact with at least one organometallic compound and at least one generator of free radicals out of the presence of air.

Abstract: A process is described for the preparation of substantially linear, amorphous random copolymers of mono-olefins or mono-olefins and unconjugated dienes with N-unsaturated lactams.At least two mono-olefins containing 2 to 20 carbon atoms, and possibly an unconjugated diene, are placed in contact, in an inert liquid medium at a temperature of between -80.degree. and +150.degree.C, with at least one such N-unsaturated lactam in the form of a complex with a Lewis acid, in the presence of a co-ordination catalyst system, until a copolymer forms.The resulting copolymers can be vulcanized, and among other properties have improved adherence to metal surfaces.

Abstract: A process is described for the preparation of substantially linear, amorphous random copolymers of mono-olefins or mono-olefins and unconjugated dienes with unsaturated nitrogen derivatives selected from N-vinylimidazoles and N-vinylimidazolines and compounds derived from them by substitution, for the hydrogen atoms fixed to the carbons in the heterocycle, of hydrocarbon or aminohydrocarbon radicals.At least two mono-olefins containing 2 to 20 carbon atoms, and possibly an unconjugated diene, are placed in contact, in an inert liquid medium at a temperature of between -80.degree. and +150.degree.C, with at least one of these nitrogen derivatives in the form of a complex with a Lewis acid, in the presence of a co-ordination catalyst system.The resulting copolymers can be vulcanized, and among other properties have excellent adherence to metal surfaces.

Abstract: Production of organic sulphoxides by the action of sulphoxides of lower molecular weight on organic sulphides in which the reaction is catalysed by one or more substances capable of supplying hydrogen ions to the reaction medium. The process permits yields to be obtained which exceed 90 percent, and the sulphoxide which is obtained is practically free from sulphone.

Abstract: A process for automated regulation of a unit producing sulphur by oxidation of hydrogen sulphide, in which the flow of gas carrying oxygen into the unit is regulated so as to keep an operating parameter, based on measurement of the sulphurous compound of the residual gases, level with a reference value.It is characterized by the fact that the control signal, used to regulate the flow of gas containing oxygen at the unit inlet, is a combination of a signal based on measurements taken at the inlet, and representing the theoretical flow of this gas needed to keep the operating parameter at its reference level and another signal representing the correction needed in this flow to adjust the instantaneous value of the parameter to the reference level.This process allow better control of the sulphur unit, with increased efficiency and reduced atmospheric pollution.