Abstract: In an actuator, a carriage coupled to an item to be displaced with a translatory movement comprises a follower element which defines contact surfaces engaged against the flanks of the thread of a micrometric screw. The contact surfaces co-operate with the thread of the screw only over a small angular portion thereof. The follower element of the carriage is held on the thread of the screw by resilient thrust means acting on the carriage so as to urge it pivotally about an axis (X--X) which is parallel to its direction of translatory movement, being prevented from moving in all the other degrees of freedom. The actuator is especially adapted for use in translator devices in which the level of precision is of the order of a micrometer.

Abstract: A process for electrophotographic matrix printing and apparatus for carrying out this process, the apparatus comprising a plane assembly of modulating strips disposed alternately along two parallel lines, an optical light guide for guiding the light emitted by a virtual pinpoint light source in the form of two convergent light sheets respectively traversing the two lines of modulators, and a rotary drum whose lateral surface consists of a photosensitive support. The optical light guide is formed of a plate with plane parallel surfaces, bounded by three rims. The first rim has a toroidal form whose center corresponds to the position of the source; the second rim has a cylindro-parabolic form and the third rim comprises a dihedron whose edge is parallel to the plane faces of the guide. Writing can be effected line by line along a direction substantially parallel to the axis of rotation of the photosensitive support.

Abstract: Method and apparatus are disclosed for precisely positioning a pair of components such as optical components, including optical fibers, utilizing an apparatus which includes a first support for mounting the first component, a second support for mounting the second component and an elastic joint formed on the first support for moving the first support in relation to the second support by bending the elastic joint. In a preferred embodiment, the elastic joint includes a pair of parallel elastically bendable arms formed on the first support and bendable in a first direction so that the elastic joint provides a translation module.

Abstract: The present invention concerns a device for aligning two optical components.This device comprises a frame composed of a first base plate having two branches which are essentially parallel to each other and a second base plate which also has two branches essentially parallel to each other. One branch carries a first mobile support which is fixed at the end of two flexible strips. The other branch carries a second mobile support being fixed at the ends of two other flexible strips. The two supports carry the two members to be assembled and may be moved relatively to each other in a plane by means of micrometric screws.This device permits to align two members with respect to each other and to fix them in their position.

Abstract: This device comprises an electrode, the diameter of which is of the same order of magnitude as the drop to be projected, which emerges on the surface of an electrically insulating support. This support is immersed in a reservoir of liquid which comprises an opening. The support is placed so that the face thereof with which the electrode is flush, is located at a certain distance recessed from the plane of the opening so that it is covered with the liquid contained in the reservoir in which is located the counter-electrode. These electrodes are connected to a source of intermittent current designed to form an electric field through the liquid which, by concentrating on that part of the electrode emerging from the support, causes the projection of a drop of liquid.

Abstract: Disclosed are improved elongated, reflective slat concentrators and elongated multi-conduit/multi-fluid collectors and systems thereof. The reflective slats are generally of rectangular configuration and extending about a curve. In systems utilizing the concentrators, the collector is located above the concentrator, i.e. forwardly of the concentrator relative to the travel of solar energy to the concentrator.

Abstract: The manufacturing of at least one photothermal converter element according to the invention consists essentially of implanting a multiplicity of substantially uniformly distributed parallely projecting transparent fibers onto a baseplate element provided with an absorbing coating of a normally solid material capable of being temporarily converted to a plastic state, thanks to the use of an array of guiding means arranged above the baseplate element. The implantation proper of the desired fiber structure is then performed by advancing a series of bundles of fibers through the array of guiding means, to the desired level above the baseplate element, and by clipping the advanced bundles to the desired length above the guiding means, so as to cause the falling with limited transverse spreading of the clipped fibers onto the coating of the baseplate element.

Abstract: Hydrogen is produced by dissociation of water in a rotary tubular reactor (1) having a receiving end covered by a cap (2) transparent to solar radiation and provided with a small window (12) connecting a collecting chamber (3) to an opaque insulated heating chamber (5).The tubular reactor (1) constitutes a "black chamber" provided with two series of tubes (7, 8) for heating and dissociating the water. Tubes (7) have a porous section (7a) for separating hydrogen by molecular diffusion according to Knudsen's principle.The concentrated solar radiation entering through the small window (12) falls on one end of the tubes (7, 8) and is largely absorbed by multiple reflections on these tubes.A slow rotation of the reactor (1) enables the bending forces and stresses due to the weight to be compensated.

Abstract: In order to improve the efficiency of a solar energy system utilizing a Fresnel lens for concentrating solar rays on a conduit system or the like, only the central portion of a Fresnel lens, otherwise of large width, is utilized and slide assemblies, each containing a plurality of slats with a reflective coating and disposed at an angle such as to reflect solar energy to the same focal point as the Fresnel lens, are disposed on each side of the lens thereby effectively increasing the aperture of the lens and increasing efficiency of concentration.

Abstract: In order to reduce energy losses by convection and/or thermal radiation from the radiation-absorbing surface of a photothermal energy converter for the utilization of solar energy, the said surface is provided with a multiplicity of projecting fibres sufficiently close to one another to suppress convection, each fibre consisting of a material which is permeable to the incident luminous radiation to be absorbed and at least partly opaque to infrared thermal radiation which may be reemitted from the said surface whereby energy losses by radiation are reduced.The fibres can be, for example, glass or plastic fibres and can be integral with or implanted in the said surface. Preferably, the fibres have diameters in the range 25 to 500 micrometers, a height of the order of 5 cm, and an average distance between fibres in the range 100 to 5000 micrometers.

Abstract: A video cathode tube having a matrix of low emission threshold field effect emitters oriented to emit toward a luminescent layer. A first system of mutually insulated conductive paths is arranged along rows of emitters with the emitters in any row electrically connected to a corresponding conductive path of the first system. A second system of mutually insulated conductive paths is disposed in contact with the luminescent layer and extends in front of columns of the emitters. A first bank of contacts individually connected to respective conductive paths of the first system are sequentially energized to a first potential, and a second bank of contacts individually connected to respective conductive paths of the second system are sequentially energized to a second potential. A control grid connectable to a voltage source is interposed between the matrix of emitters and the second system of conductive paths.