Abstract: A mechanical speed reducer, in particular for a device for driving at least one wheel of an aircraft landing gear, this reducer including a first sun gear including external toothing, first planet gears meshed with the external toothing of the first sun gear, these first planet gears being carried by a first planet carrier, a stationary ring gear meshed with the planet gears, and second planet gears meshed with a ring gear and with an external toothing of said first planet carrier, these second planet gears being carried by a second planet carrier.

Abstract: A device for driving at least one wheel of an aircraft landing gear including at least one landing gear wheel, this wheel including a rim, an electric motor including a shaft, a mechanical transmission system between the shaft of the motor and the rim, this mechanical transmission system including a mechanical reducer including a sun gear secured in rotation to the shaft of the motor, a ring gear, and planet gears which are carried by a planet carrier and which each includes three external toothings, including a median external toothing which is meshed with a toothing of the sun gear, and two lateral external toothings which are respectively meshed with toothings of the ring gear.

Abstract: A device for driving at least one wheel of an aircraft landing gear is provided. The device includes at least one wheel having a rim, an electric motor having a shaft, and a mechanical transmission system for mechanical transmission between the shaft of the motor and the rim. The mechanical transmission system includes a mechanical reduction gear. The mechanical reduction gear includes a sun gear secured in rotation to the shaft and having an external toothing, a stationary ring gear with internal toothing, a movable ring gear secured in rotation to the rim and having an internal toothing, and planet gears that are meshed with the sun gear and each have two external toothing meshed respectively with the toothing of the stationary and movable ring gears.

Abstract: The implant (12) according to the invention comprises a tubular frame (16), a plurality of distal arms (18) capable of pressing on a first face of a tissue, and a plurality of proximal arms (20) having an end (62) connected to the frame and a free end (64) intended to press on a second face of the tissue to clamp the tissue. The implant comprises a first integral assembly including a first part (38) of the frame and the proximal arms (20), and a second integral assembly including a second part of the frame (40) and the distal arms (18), the first assembly and the second assembly being attached one on top of the other. The first part (38) of the frame is in the form of a proximal sleeve, extending longitudinally between a proximal end (41) and a distal end (43) of the sleeve. The connected end (62) of each proximal arm (20) is connected to the distal end (43) of the proximal sleeve (38), and the free end (64) of each proximal arm (20) extends beyond that distal end (43) of the proximal sleeve (38).

Abstract: The implant (12) according to the invention comprises a tubular frame (16), a plurality of distal arms (18) capable of pressing on a first face of a tissue, and a plurality of proximal arms (20) having an end (62) connected to the frame and a free end (64) intended to press on a second face of the tissue to clamp the tissue. The implant comprises a first integral assembly including a first part (38) of the frame and the proximal arms (20), and a second integral assembly including a second part of the frame (40) and the distal arms (18), the first assembly and the second assembly being attached one on top of the other. The first part (38) of the frame is in the form of a proximal sleeve, extending longitudinally between a proximal end (41) and a distal end (43) of the sleeve. The connected end (62) of each proximal arm (20) is connected to the distal end (43) of the proximal sleeve (38), and the free end (64) of each proximal arm (20) extends beyond that distal end (43) of the proximal sleeve (38).

Abstract: Rare earth glass-polishing compositions of improved homogeneity and reproducibility are prepared by (a) simultaneously continuously admixing a cerium salt solution, a basic solution and a solution of at least one acid and/or one salt, the anion or anions of which being adopted to form insoluble rare earth compounds, the number of equivalents of base being equal to or greater than the number of equivalents of cerium, and the pH of the reaction medium being greater than about 6; (b) filtering the precipitate which results from the reaction medium; (c) drying said recovered precipitate; and (d) calcining said dried precipitate.

Abstract: Cerium based glass polishing compositions, well adapted for the polishing, e.g., of optical glass, are comprised of (i) at least one crystalline phase of CeO.sub.2 type, and (ii) a crystalline phase which comprises a rare earth pyrosilicate having the formula Ln.sub.2-x Ce.sub.x Si.sub.2 O.sub.7, wherein Ln is at least one lanthanide or yttrium and x is a number ranging from zero to less than 2.

Abstract: Rare earth glass-polishing compositions of improved homogeneity and reproducibility are prepared by (a) simultaneously continuously admixing a cerium salt solution, a basic solution and a solution of at least one acid and/or one salt, the anion or anions of which being adopted to form insoluble rare earth compounds, the number of equivalents of base being equal to or greater than the number of equivalents of cerium, and the pH of the reaction medium being greater than about 6; (b) filtering the precipitate which reuslts from the reaction medium; (c) drying said recovered precipitate; and (d) calcining said dried precipitate.