Abstract: A lapping method and device for lapping magnetic heads to provide an air bearing surface with improved surface quality including increased smoothness, reduced rolloff, and reduced recession. The lapping machine includes a lapping plate having a grinding surface, a linear motion mechanism for moving the ABS over the grinding surface in a first, linear direction, and a micro-advance mechanism for controllably advancing the workpiece over the grinding surface in a second direction that is preferably perpendicular. The lapping method comprises affixing the unfinished magnetic head proximate to the lapping plate and depositing an abrasive slurry on the grinding surface. An initial rough lapping stage is performed, including moving the grinding surface so that the workpiece is lapped to a first predetermined target specification.

Abstract: The process assures the correction of the control of an actuator acting on the speed as a function of the error E=N.sub.c -N between a set-point speed (N.sub.c) and the actual speed (N), and of the time derivative (E') of this error. A correction (.DELTA.u) for the control of the actuator is derived from the addition of first (.DELTA.u.sub.1) and second (.DELTA.u.sub.2) partial corrections which are functions of the speed error (E) and the time derivative (E') of this error, respectively. These corrections are defined as a function of the relative position of the value of the error, or of the error derivative, with respect to at least two predetermined values of the error (or the derivative of the error), each of which has an associated predetermined value of the partial correction .DELTA.u.sub.1 (or .DELTA.u.sub.2).

Abstract: A method for cross-linking chlorinated (co)polymers involves reacting such (co)polymers at between 50.degree. and 230.degree. C. in the absence of solvent with an organometallic amino-type derivative of tin, lead, antimony or bismuth to provide cross-linked compositions and shaped objects.

Abstract: The present invention relates to functionalized chlorinated (co)polymers and methods for their preparation. The functionalization is performed with an organometallic compound where the metal may be tin, lead, antimony or bismuth. The organic groups are hydrocarbons which may be substituted and one group is either a secondary amine or an ether which is eventually substituted by a trialkoxysilane or a hydroxy group. The preferred chlorinated polymer is PVC and the preferred functionalizing agent is an organotin compound.

Abstract: Method for crosslinking (co)polymers comprising chlorine, ester, NH or carbonate groupings, according to which said (co)polymer is reacted at between 100.degree. and 300.degree. C., and without the presence of a solvent, with a tin-, lead-, bismuth- or antimony-based organometallic alcoholate. Mixtures, crosslinkable compositions and shaped objects are also described.

Abstract: A process for cross-linking (co)polymers having ester functions involves reacting a polyalcohol-derived polyester and a polyacid-derived polyester in the presence of an alkaline alcoholate at a temperature in excess of 180.degree. C.

Abstract: This invention relates to a process of cross-linking a halogenated polymer be nucleophilic substitution of the halogen atoms by means of a coupling agent constituted by an organo-metallic thiolate, wherein said coupling thiolate is an alkaline or alkaline-earth thiolate not comprising an amine function, of general formula: ##STR1## in which: Me designates an alkaline or alkaline-earth metal;R.sub.1 designates an aliphatic or aromatic radical and;R.sub.2 designates a group selected from the group constituted by: ##STR2## in which R.sub.3, R.sub.4 and R.sub.5 designate an alkyl or aryl group not comprising an amine function.

Abstract: Method for preparing a polyolefin modified by grafting, in which in a first phase, peroxides are grafted in known manner onto a polyolefin chain with a mixture of oxygen and ozone, wherein, in a second phase, a vinyl monomer with at least one epoxy function is added to the resulting peroxidized polyolefin, and in a third phase, the resulting mixture is polymerized.The invention finds an application in the preparation of polypropylene with excellent adhesive properties especially with iron, leather and glassfibers.