Abstract: A device for monitoring an available thrust margin of an anti-torque member of a rotorcraft as a function of flight conditions, said rotorcraft comprising a power plant driving at least one main rotor participating at least in the lift of said rotorcraft, said anti-torque member participating in the control of the yaw movements of said rotorcraft.

Abstract: A device for monitoring an available thrust margin of an anti-torque member of a rotorcraft as a function of flight conditions, said rotorcraft comprising a power plant driving at least one main rotor participating at least in the lift of said rotorcraft, said anti-torque member participating in the control of the yaw movements of said rotorcraft.

Abstract: A process for producing substantially optically pure sertraline utilizes chromatographic separation on a solid stationary chiral phase of spherical clay particles having an interlayer containing an optically pure metal-organic complex, and a liquid mobile phase preferably containing at least methyl acetate. The liquid mobile phase is preferably free of acetonitrile. The process is operable at temperatures above 40° C.

Abstract: A process for producing substantially optically pure sertraline utilizes chromatographic separation on a solid stationary chiral phase of spherical clay particles having an interlayer containing an optically pure metal-organic complex, and a liquid mobile phase preferably containing at least methyl acetate. The liquid mobile phase is preferably free of acetonitrile. The process is operable at temperatures above 40° C.

Abstract: This invention relates to a system for strictly positioning along an axis an object such as a wafer of semi-conducting material during a process of constructing integrated circuits, wherein it comprises:means for controlling the drive means for causing the carriage to make a displacement of acquisition of which the amplitude is at least equal to the step of the second optical grating;a generator generating, during said displacement of acquisition, a periodic reference signal, of period equal to the step of said second grating;multiplication means for forming the product of said period reference signal and of the signal actually delivered by said photoelectric sensor;means for summing the signal formed by the succession of said products;calculating means for determining the possible offset existing between said optical gratings; andmeans controlling the drive means to bring said optical gratings into strict alignment.

Abstract: An imaging apparatus, for instance a wafer stepper, has an optical system for forming an image of an object such as a reticle and it has a focusing device. The focusing device has detector means for determining deviations between the actual image surface of the optical system and a second surface (surface of the semiconductor wafer) on which the image is to be formed. The focusing device includes two sets of detector means, each said set having means fast with the optical system and constructed to focus a spot of monochromatic light under a large angle of incidence onto said actual image surface and means for collecting the light reflected by said second surface and focusing it on a differential light detector so located that the image of the spot is centered on the detector when the two surfaces coincide and means for summing differential signals supplied by the detectors of both sets, said sets being arranged for the light path in the two sets of detector means to be substantially reverse from each other.