Patents Assigned to Ecole Polytechnique
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Publication number: 20020131464Abstract: An electrically pumped VCSEL and a method of its fabrication are presented. The VCSEL comprises an active cavity material sandwiched between top and bottom DBR stacks, the top DBR having at least one n-semiconductor layer. The device defines an aperture region between the structured surface of the active cavity material and the n-semiconductor layer of the top DBR stack. The structured surface is formed by a top surface of a mesa that includes at least the upper n++ layer of a p++/n++ tunnel junction and the surface of a p-type layer outside the mesa. The structured surface is fused to the surface of the n-semiconductor layer of the DBR stack due to the deformation of these surfaces, thereby creating an air gap in the vicinity of the mesa between the fused surfaces.Type: ApplicationFiled: March 15, 2001Publication date: September 19, 2002Applicant: Ecole Polytechnique Federale De LausanneInventors: Alexei Sirbu, Vladimir Iakovlev, Alok Rudra, Elyahou Kapon
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Publication number: 20020132948Abstract: A high molecular weight water soluble acrylamide based polymer having improved flocculating and dewatering properties is provided. The polymer is prepared by a process in which a small quantity of a chain branching agent is added to the polymerization reaction mixture continuously or stepwise while the monomers are polymerized. The polymer is useful in solid/liquid separations such as flocculants and coagulants in wastewater treatment applications, and as thickening agents.Type: ApplicationFiled: March 13, 2002Publication date: September 19, 2002Applicant: Ecole Polytechnique Federale De Lausanne (EPFL)Inventors: Jose Hernandez-Barajas, Christine Wandrey, David Hunkeler
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Patent number: 6449338Abstract: An X-ray emission device having a microwave source and a resonant chamber. The resonant chamber contains a hermedically sealed volume of gas, a magnetic structure defining a geometrical electron-confinement zone in which electrons move at high speed. At least one target is placed in an electron path in order to emit X-rays. Each target is offset with respect to a mid-region of the geometrical conbinement zone.Type: GrantFiled: November 3, 2000Date of Patent: September 10, 2002Assignee: Ecole PolytechniqueInventors: Marthe Bacal Verney, Jean-Max Buzzi, Christelle Gaudin, Dominique De Lapparent, Claude Rouille, Laurent Schwartz, Konstantin Serebrennikov
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Patent number: 6426827Abstract: Electrochromic and photoelectrochromic devices using nanocrystalline semiconductor electrodes with a high specific surface area and surface-absorbed electrochromic molecules are disclosed.Type: GrantFiled: April 14, 2000Date of Patent: July 30, 2002Assignee: Ecole Polytechnique Federale de LausanneInventors: Pierre Bonhôte, Lorenz Walder, Michael Grätzel
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Patent number: 6320624Abstract: Given two video sequences, a composite video sequence can be generated which includes visual elements from each of the given sequences, suitably synchronized and represented in a chosen focal plane. For example, given two video sequences with each showing a different contestant individually racing the same down-hill course, the composite sequence can include elements from each of the given sequences to show the contestants as if racing simultaneously. A composite video sequence can be made also by similarly combining a video sequence with an audio sequence.Type: GrantFiled: January 16, 1998Date of Patent: November 20, 2001Assignee: Ecole Polytechnique FédéraleInventors: Serge Ayer, Martin Vetterli
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Patent number: 6294622Abstract: A high molecular weight water soluble acrylamide based polymer having improved flocculating properties is provided. The polymer is prepared by a process, in which a small quantity of a chain branching agent is added to the polymerization reaction mixture continuously or semi-continuously while the monomers are polymerized. The polymer is useful in solid/liquid separations such as flocculants and coagulants in waste water treatment applications, and as thickening agents.Type: GrantFiled: September 27, 1999Date of Patent: September 25, 2001Assignee: Ecole Polytechnique Federale de Lausanne (EPFL)Inventors: Jose Hernandez Barajas, Christine Wandrey, David Hunkeler
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Patent number: 6258275Abstract: Affinity macroligands (AML) comprising a reversibly water soluble poly-N-alkylacrylamide linked to a ligand, and their use in the separation of a target substance from a mixture comprising the target substance and other materials are disclosed. Preferred AMLs have number average molar masses of less than 7,000 g/mol (chain length n typically about 25), mass distributions of less than 1.2 and narrow precipitation-solubility temperature (NPST) interval, typically in the range of 1-2° C.Type: GrantFiled: October 1, 1999Date of Patent: July 10, 2001Assignee: Ecole Polytechnique Federale de LausanneInventors: Ruth Freitag, Frédéric Garret-Flaudy
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Patent number: 6249588Abstract: The present invention relates to a new method and apparatus for authenticating documents such as banknotes, trust papers, securities, identification cards, passports, etc. The documents may be printed on any support, including transparent synthetic materials and traditional opaque materials such as paper. This invention is based on moire patterns occuring between superposed dot-screens. By using specially designed basic screen and master screen, where at least the basic screen is comprised in the document, a moire intensity profile of a chosen shape becomes visible in their superposition, thereby allowing the authentication of the document. If instead of the master screen a microlens array is used for the authentication purpose, the document comprising the basic screen may be printed on an opaque reflective support, thereby enabling the visualization of the moire intensity profile by reflection.Type: GrantFiled: August 28, 1995Date of Patent: June 19, 2001Assignee: Ecole Polytechnique Fédérale de LausanneInventors: Isaac Amidror, Roger D. Hersch
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Patent number: 6245988Abstract: A photosensitizer complex of formulae (Ia) MX3Lt or (Ib) MXYLt in which M is a transition metal selected from ruthenium, osmium, iron, rhenium and technetium, preferably ruthenium or osmium; each X is a co-ligand independently selected from NCS—, Cl—, Br—, I—, CN—, NCO—, H2O, NCN2−; pyridine unsubstituted or substituted by at least one group selected from vinyl, primary, secondary or tertiary amine, OH and C1-30 alkyl, preferably NCS—; and Lt is a tridentate ligand comprising heterocycles such as pyridine, thiophene, imidazole, pyrazole, triazole, carrying at least one carboxylic, phosphoric, hydoxamic acid or a chelating group. A photovoltaic cell comprising an electrically conductive layer deposited on a support to which at least one titanium dioxide layer has been applied and, as a photosensitizer applied to the titanium dioxide layer, a photosensitizer complex of formula (Ia) or Ib) as specified above.Type: GrantFiled: November 2, 1999Date of Patent: June 12, 2001Assignee: Ecole Polytechnique Federale de LausanneInventors: Michael Grätzel, Mohammad Khaja Nazeeruddin, Péter Péchy
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Patent number: 6208353Abstract: For annotating a digital image with information from a digital map, features which are visible from a viewer position are extracted from the map. The extracted features are matched with corresponding features in the image, and feature annotations are transferred from the map to the image to obtain an integrated view. The technique facilitates the annotation of photographs, and it can be included in navigation and simulation systems.Type: GrantFiled: September 5, 1997Date of Patent: March 27, 2001Assignee: Ecole Polytechnique Fedérale de LausanneInventors: Serge Ayer, Martin Vetterli
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Patent number: 6186594Abstract: The flexible contour wheelchair backrest comprises two side posts, and a flexible backrest body extending between the two side posts. The flexible backrest body comprises a plurality of transversally extending and vertically spaced apart flexible straps each interconnecting the two side posts and each having an adjustable length, and a plurality of substantially stiff and malleable stays intersecting at least one of the flexible straps at right angle. Each side post defines an elongated curved front face for receiving the flexible backrest body. This elongated curved front face has a forwardly bulging section for inducing a depth dimension to the flexible backrest body to fit the posterior lateral contour of a user's back and thereby provide lateral support to the user's trunk. A mechanism is used to adjust the distance between the forwardly bulging sections of the elongated curved front faces.Type: GrantFiled: April 7, 1998Date of Patent: February 13, 2001Assignee: Corporation de l'ecole PolytechniqueInventors: Claude Valiquette, Frédéric Parent, Jean Dansereau
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Patent number: 6172902Abstract: A non-volatile random access memory (NVRAM) of the type with magnetoresistive memory elements (1) connected by sets of non-intersecting conductor sense lines (3, 4) which define the address of each memory element (1) and are connectable to a magnetic write/read recording unit. The memory elements are a plurality of magnetoresistive submicron dots or wires (1) embedded in a membrane (2) through which the submicron dots or wires extend. The sets of non-intersecting conductor sense lines (3, 4) are connected to the opposite ends of the submicron dots or wires (1) on opposite sides of the membrane.Type: GrantFiled: August 13, 1999Date of Patent: January 9, 2001Assignee: Ecole Polytechnique Federale de Lausanne (EPFL)Inventors: Jean-Eric Wegrowe, Jean-Philippe Ansermet, Scott E. Gilbert
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Patent number: 6119607Abstract: The process is conducted in an incinerator installation comprising i) a generally vertical, cylindrical riser pipe, ii) a vertically extending annular chamber surrounding the riser pipe and containing a fluidized bed of granular inert material, and iii) a burner for producing an upwardly extending flame in the lower portion of the riser pipe. Granular solid waste is supplied at a constant flow rate to the bed, directly or through the burner. Granular solid waste and bed material is transferred from the lower portion of the annular chamber to the lower portion of the riser pipe directly in the flame. The flame burns the granular solid waste, heats the inside of the riser pipe to a temperature greater than or equal to 900.degree. C.Type: GrantFiled: May 9, 1997Date of Patent: September 19, 2000Assignee: Corporation de l'Ecole PolytechniqueInventors: Christophe Guy, Robert Legros, Jamal Chaouki, Rene-Jean Lavallee, Luc Bussac, Luc Mauillon, Lukanda Mukadi
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Patent number: 6074875Abstract: This application relates to cell lines transfected with (a) nucleic acid encoding one or more hormone receptors, the receptors being capable of transmitting a signal, and (b) nucleic acid encoding a desired polypeptide, the nucleic acid encoding the polypeptide being under the control of a promoter containing regulatory elements responsive to the signal transmitted by the receptor(s) so that transcription of the nucleic acid encoding the desired polypeptide is modulated by the level of the hormone(s) in the patient. Preferably, the receptors are the GIP or GLP-1 receptors controlling the production of insulin in the cells in response to changes in the metabolic status of a patient. The application also relates to compositions comprising these cells and their use in methods of medical treatment.Type: GrantFiled: March 4, 1998Date of Patent: June 13, 2000Assignees: Ecole Polytechnique Federale de Lausanne, Universite de Lausanne, Centre Hospitalier Universitaire VaudoisInventor: Bernard Thorens
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Patent number: 6069313Abstract: A plurality of series-connected elements are arranged, as parallel elongated stripes, on a common electrically insulating transparent substrate (1). Each element comprises a photoanode (4), a porous counterelectrode or cathode (6) and an intermediate electrically insulating porous layer (5) separating the photoanode (4) from the cathode (6). The pores of the intermediate layer (5), the photoanode (4) and the cathode (6) are at least partially filled with an electron transferring electrolyte. An intermediate layer (2) of a transparent electrically conducting material is interposed between the substrate (1) and each photoanode (4). The cathode (6) of the first photovoltaic element of the series is electrically connected with a first terminal (9) of the battery. The cathode (6) of each following element is connected with the intermediate conducting layer (2) of the preceding element, over a gap (3) separating the respective intermediate layers (2) of these two elements.Type: GrantFiled: June 5, 1998Date of Patent: May 30, 2000Assignee: Ecole Polytechnique Federale de LausanneInventor: Andreas Kay
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Patent number: 6067184Abstract: Electrochromic and photoelectrochromic devices using nanocrystalline semiconductor electrodes with a high specific surface area and surface-absorbed electrochromic molecules are disclosed.Type: GrantFiled: October 13, 1998Date of Patent: May 23, 2000Assignee: Ecole Polytechnique Federale De LausanneInventors: Pierre Bonhote, Lorenz Walder, Michael Gratzel
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Patent number: 5995638Abstract: New method and apparatus for authenticating security documents such as banknotes, passports, etc. which may be printed on any support, including transparent synthetic materials and traditional opaque materials such as paper. The invention is based on moire patterns occuring between superposed dot-screens. By using a specially designed basic screen and master screen, where at least the basic screen is comprised in the document, a moire intensity profile of a chosen shape becomes visible in their superposition, thereby allowing the authentication of the document. If a microlens array is used as a master screen, the document comprising the basic screen may be printed on an opaque reflective support, thereby enabling the visualization of the moire intensity profile by reflection. Different variants of the invention are disclosed, some of which are specially adapted for use as covert features.Type: GrantFiled: July 5, 1996Date of Patent: November 30, 1999Assignee: Ecole Polytechnique Federale de LausanneInventors: Isaac Amidror, Roger D. Hersch
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Patent number: 5986291Abstract: The channel region of the FET device has a first portion adjacent the source which has a higher bandgap energy or a higher electron affinity than a remaining portion of the channel. A quasi-electric field in the channel near the source is intensified and as a result, accelerates charge carriers in the channel and increases switching speed. An infrared controlled FET device is also disclosed in which a low bandgap channel layer has a large bandgap layer deposited on it to result in a conduction band discontinuity at the junction between the large bandgap semiconductor layer and the low bandgap channel layer and a two-dimensional electron gas (2DEG) channel in the low bandgap channel layer so that photons reaching the 2DEG eject charges and allow conduction through the channel layer.Type: GrantFiled: October 12, 1993Date of Patent: November 16, 1999Assignee: La Corporation de L'ecole PolytechniqueInventors: John F. Currie, Chetlur S. Sundararaman
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Patent number: 5981445Abstract: The new preparation process for making fine high specific surface ceramic powders suitable as catalysts or precursors for ceramics uses lanthanum (or other rare earth lanthanide) oxide as one of the precursors. The oxide is mixed with water to form a liquid slurry, whereby it is transformed to the hydroxide by reaction with water. The resulting hydroxide slurry, which can be milled to reduce the particle size and to speed up the reaction, is then combined, while stirring vigorously to assure homogenous mixing, with a solution of required amount of remaining metal nitrate precursors, for example strontium and cobalt nitrates. The reaction between lanthanum hydroxide and transition metal nitrates produces a colored (color depending on the transition metal) slurry consisting of metal hydroxides suspended in aqueous nitrate solution with pH>2. This perovskite precursor slurry is spray-frozen and freeze dried.Type: GrantFiled: June 17, 1996Date of Patent: November 9, 1999Assignee: Corporation de I'Ecole PolytechniqueInventors: Jitka Kirchnerova, Danilo Klvana
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Patent number: 5968326Abstract: A composite membrane is disclosed fabricated by depositing an inorganic ion-conducting thin film on a cation-selective organic polymer membrane substrate using Pulse Laser Deposition (PLD) or reactive magnetron sputtering. The fabricated membrane combines the advantages of the polymeric membrane including flexibility and low electrical resistance, with the advantages of the inorganic membrane film including resistance to fouling, high selectivity for alkali metal ions over hydrogen ions and resistance to oxidizing chemicals; electromembrane systems and processes for example alkali metal sensing electrodes and other membrane-based electrochemical detectors, electrolytic and electrodialytic systems incorporate such membranes thus improving their performance in terms of current efficiency, salt to acid conversion ratio, reliable operation and membrane life.Type: GrantFiled: April 8, 1998Date of Patent: October 19, 1999Assignees: Pulp and Paper Research Institute of Canada, Ecole PolytechniqueInventors: Arthur Yelon, Michael Paleologou, Dentcho Ivanov, Ricardo Izquierdo, Michel Meunier