摘要:
Enzymes are convalently found to anionic or cationic hydrophilic polymeric carriers formed by essentially complete reaction of pendent anhydride groups of ethylene-maleic anhydride copolymer (EMA) with a diamine selected from the group consisting of hydrazine, P, P'-diaminodiphenylmethane and 1,6-diaminohexane to produce resins having pendent amine groups. The EMA-hydrazide and EMA- P,P'-diaminodiphenylmethane resins can be rendered cationic by reaction with N,N-dimethyl-1,3-propanediamine.
摘要:
The invention relates to a semi-conductor optical amplifier insensitive to the polarization of light. The active layer (20) of this amplifier is made up of an alternating series of solid sub-layers alternately under tensile stress (21) and compressive stress (22) and having the same forbidden band-width. The sub-layers under tensile stress (21) favour the propagation of the TM mode of polarization of light and the sub-layers under compression (22) favour the propagation of the TE mode of polarization of light. In addition, the thicknesses of the sub-layers have values which ensure equal gains G(TE) and G(TM) for the active layer.
摘要:
Primary molecules are formed by sublimation in a sublimation chamber (2), they are then transferred at a transfer flow-rate to a decomposition head (10) at a higher temperature, and they are transformed therein into secondary molecules that are lighter in weight to form molecular beams (16). In accordance with the invention, the transfer flow-rate is adjusted by adjusting an effective vector flow-rate which is the vector flow-rate of a vector gas inserted into the sublimation chamber via a feed tube (26) and sucked out via a suction tube (30). The invention applies, in particular, to making III-V type semiconductor components by molecular beam epitaxy.
摘要:
A vacuum evaporation device incorporates a main treatment enclosure connected to an auxiliary chamber containing a material evaporation cell. The cell is fixed to a tight bellows displacement member able to displace the cell between a first advanced position towards a main enclosure and a second retracted position. A sealing valve provided with a slide is provided for the main enclosure from the auxiliary chamber, whereby the material of the evaporation cell can thus be changed without placing the main enclosure under atmosphere again. A fixed heating tube, connecting the main enclosure to the auxiliary chamber, has a first end engaged in the main enclosure and a second end issuing into the auxiliary chamber. The second end is provided with an end piece made from a thermally insulating material ensuring mechanical continuity and thermal insulation with the support part and able to bearingly receive the evaporation cell when the latter is in the advanced position. The slide of the sealing valve is inserted between the end piece and the evaporation cell when the latter is in the retracted position, the travel of the cell between these end positions and consequently travel of the bellows being limited to the space necessary for closing the valve.
摘要:
A common corrective eyeglass lens blank and a common mirror, Plano or magnifying, are brought together in a “compact” (small sized) construction and assembly to provide the very thing long desired in mirrors and not elsewhere found—corrected vision and ample working room between the eyes and any lenses, at the same time, at reasonable cost, in an elegance of implementation.
摘要:
The invention relates to wavelength converters for optical signals, as used in telecommunications, in particular for routing signals. The invention relates in particular to a wavelength converter including an interferometer structure for delivering an output optical signal, in which converter first and second branches, including at least one first semiconductor optical amplifier, are coupled to input peripheral semiconductor optical amplifiers and/or to an output peripheral semiconductor optical amplifier, wherein the structure of the active waveguide of at least one peripheral amplifier is so designed that it has a ratio of active area to confinement factor greater than that of the active waveguide of said first amplifier.
摘要:
From a top face of a semiconductor structure of the III-V type, inter-diffusion of elements between the wells and the barriers of an internal quantum structure is hot induced. The inter-diffusion is performed in one segment of the structure only, namely a segment in which the characteristic wavelength is to be shifted so as to constitute an amplitude modulator, another segment of the structure including a Bragg grating so as to constitute a laser emitter. In accordance with the invention, the inter-diffusion is induced by a layer of indium maintained in contact with the top face by means of a dielectric encapsulation layer. The invention is applicable in particular to optical telecommunications.
摘要:
The present invention relates to novel isocyano derivatives of linear or cross-linked, natural or synthetic macromolecules, the derivatives being of the general formula P--O--Q--NC, wherein P is the macromolecular backbone, the oxygen atom is part of the hydroxy group, Q is a group --(CH.sub.2).sub.n --wherein n is an integer of at least 3 carbon atoms, and up to about 20 carbon atoms, or Q is an aralkyl group, to a process for preparing such derivatives and to a process of linking to same biologically active proteins and to the products thus obtained.
摘要:
A semiconductor Bragg reflector and to a method of fabricating it. The reflector comprises a plurality of stacked layers on a substrate of a III-V type material, one of the stacked layers forming a holographic grating. The layer forming the grating comprises an alternating succession of air pockets and of III-V type material. Such a reflector is particularly suitable for use in laser devices.
摘要:
In a method of fabricating a surface emitting semiconductor layer, to achieve good electrical confinement and good flatness of the mirrors delimiting the resonant cavity of the laser, an electrical confinement layer is made by growing a localized aluminum alloy layer on the active layer, except for an opening area on top of which the mirror is to be formed. After epitaxial regrowth, the alloy layer is oxidized laterally. Applications include the fabrication of semiconductor lasers on III-V substrates such as InP and GaAs.