Patents by Inventor Naijuan Wu
Naijuan Wu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9349947Abstract: An electric-pulse-induced-resistance change device (EPIR device) is provided which is a resistance switching device. It has a buffer layer inserted between a first active resistance switching layer and a second active resistance switching layer, with both active switching layers connected to electrode layers directly or through additional buffer layers between the active resistance switching layers and the electrodes. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. The second active resistance switching layer may, in the alternative, be an ion donating layer, such that the structure becomes: electrode-active layer-buffer layer-ion donating layer-electrode. The EPIR device is constructed to mitigate the retention challenge.Type: GrantFiled: November 12, 2015Date of Patent: May 24, 2016Assignee: Board of Regents, University of HoustonInventors: Alex Ignatiev, Kristina Young-Fisher, Rabi Ebrahim, Naijuan Wu
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Publication number: 20160064660Abstract: An electric-pulse-induced-resistance change device (EPIR device) is provided which is a resistance switching device. It has a buffer layer inserted between a first active resistance switching layer and a second active resistance switching layer, with both active switching layers connected to electrode layers directly or through additional buffer layers between the active resistance switching layers and the electrodes. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. The second active resistance switching layer may, in the alternative, be an ion donating layer, such that the structure becomes: electrode-active layer-buffer layer-ion donating layer-electrode. The EPIR device is constructed to mitigate the retention challenge.Type: ApplicationFiled: November 12, 2015Publication date: March 3, 2016Applicant: Board of Regents, University of HoustonInventors: Alex Ignatiev, Kristina Young-Fisher, Rabi Ebrahim, Naijuan Wu
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Patent number: 9218901Abstract: An electric-pulse-induced-resistance change device (EPIR device) is provided which is a resistance switching device. It has a buffer layer inserted between a first active resistance switching layer and a second active resistance switching layer, with both active switching layers connected to electrode layers directly or through additional buffer layers between the active resistance switching layers and the electrodes. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. The second active resistance switching layer may, in the alternative, be an ion donating layer, such that the structure becomes: electrode-active layer-buffer layer-ion donating layer-electrode. The EPIR device is constructed to mitigate the retention challenge.Type: GrantFiled: December 1, 2011Date of Patent: December 22, 2015Assignee: Board of Regents, University of HoustonInventors: Alex Ignatiev, Naijuan Wu, Kristina Young-Fisher, Rabi Ebrahim
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Patent number: 8409879Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The selected duration of the electrical pulse is in the range of from about 8 nanosecond to about 100 milliseconds. The selected maximum value of the electrical pulse is in the range of from about 1 V to about 150 V. The electrical pulse may have square, saw-toothed, triangular, sine, oscillating or other waveforms, and may be of positive or negative polarity.Type: GrantFiled: May 23, 2011Date of Patent: April 2, 2013Assignee: Board of Regents, University of HoustonInventors: Naijuan Wu, Xin Chen, Alex Ignatiev
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Publication number: 20120126195Abstract: An electric-pulse-induced-resistance change device (EPIR device) is provided which is a resistance switching device. It has a buffer layer inserted between a first active resistance switching layer and a second active resistance switching layer, with both active switching layers connected to electrode layers directly or through additional buffer layers between the active resistance switching layers and the electrodes. This device in its simplest form has the structure: electrode-active layer-buffer layer-active layer-electrode. The second active resistance switching layer may, in the alternative, be an ion donating layer, such that the structure becomes: electrode-active layer-buffer layer-ion donating layer-electrode. The EPIR device is constructed to mitigate the retention challenge.Type: ApplicationFiled: December 1, 2011Publication date: May 24, 2012Inventors: Alex Ignatiev, Naijuan Wu, Kristina Young-Fisher, Rabi Ebrahim
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Patent number: 8089111Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.Type: GrantFiled: September 17, 2009Date of Patent: January 3, 2012Assignee: Board of Regents, University of HoustonInventors: Naijuan Wu, Xin Chen, Alex Ignatiev
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Publication number: 20110304423Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The selected duration of the electrical pulse is in the range of from about 8 nanosecond to about 100 milliseconds. The selected maximum value of the electrical pulse is in the range of from about 1 V to about 150 V. The electrical pulse may have square, saw-toothed, triangular, sine, oscillating or other waveforms, and may be of positive or negative polarity.Type: ApplicationFiled: May 23, 2011Publication date: December 15, 2011Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
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Patent number: 7955871Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.Type: GrantFiled: September 17, 2009Date of Patent: June 7, 2011Assignee: Board of Regents, University of HoustonInventors: Naijuan Wu, Xin Chen, Alex Ignatiev
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Publication number: 20100134239Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.Type: ApplicationFiled: September 17, 2009Publication date: June 3, 2010Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
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Publication number: 20100014344Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.Type: ApplicationFiled: September 17, 2009Publication date: January 21, 2010Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
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Patent number: 7608467Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.Type: GrantFiled: January 13, 2005Date of Patent: October 27, 2009Assignee: Board of Regents University of HoustonInventors: Naijuan Wu, Xin Chen, Alex Ignatiev
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Patent number: 7510819Abstract: A thin film solid oxide fuel cell (TFSOFC) having a porous metallic anode and a porous cathode is provided. The fuel cell is formed by using a continuous metal foil as a substrate onto which is deposited a thin anode metal layer which is then patterned to reveal an array of pores in the anode. A dense thin film electrolyte is then deposited onto the porous anode layer overcoating the anode and filling the anode pores. The substrate foil layer is then removed to allow for exposure of the porous anode/electrolyte to fuel. The cathode is then formed on the electrolyte by depositing a cathode thin film cap using known film deposition techniques. Further processing may be used to increase the porosity of the electrodes. The metal foil may be treated to have an atomically ordered surface, which makes possible an atomically ordered anode and atomically ordered thin film electrolyte for improved performance.Type: GrantFiled: May 18, 2006Date of Patent: March 31, 2009Assignee: Board of Regents, University of HoustonInventors: Xin Chen, Naijuan Wu, Alex Ignatiev, Yuxiang Zhou
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Patent number: 7381492Abstract: A thin film solid oxide fuel cell (TFSOFC) having a porous metallic anode and a porous cathode is provided. The fuel cell is formed by using a continuous metal foil as a substrate to epitaxially deposit a thin film electrolyte on one surface of the foil. The metal foil may then be made porous by photolithographically patterning and etching the other surface of the foil to form holes extending through the foil to the electrolyte/foil interface. The cathode is then formed on the electrolyte by depositing a second thin film using known film deposition techniques. Further processing may be used to increase the porosity of the electrodes. The metal foil may be treated before film deposition to have an atomically ordered surface, which makes possible an atomically ordered thin film electrolyte.Type: GrantFiled: November 10, 2003Date of Patent: June 3, 2008Assignee: University of HoustonInventors: Xin Chen, Naijuan Wu, Alex Ignatiev
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Publication number: 20060240575Abstract: The present invention provides a method for capturing optical micro detectors for improved surgical handling during implantation into an eye comprising the steps of providing an optically active thin film heterostructure on a soluble substrate; forming an array comprising individual optical microdetectors from the optically active thin film heterostructure; attaching the optical microdetector array onto a biodegradable polymer carrier membrane; and separating the optical microdetector array attached to the biodegradable polymer carrier membrane from the soluble substrate thereby capturing the optical microdetectors in the bio-polymer carrier membrane for improved handling of the optical micro-detectors during transfer and implantation into the eye.Type: ApplicationFiled: June 27, 2006Publication date: October 26, 2006Inventors: NaiJuan Wu, Ali Zomorrodian, Alex Ignatiev
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Publication number: 20060210706Abstract: A thin film solid oxide fuel cell (TFSOFC) having a porous metallic anode and a porous cathode is provided. The fuel cell is formed by using a continuous metal foil as a substrate onto which is deposited a thin anode metal layer which is then patterned to reveal an array of pores in the anode. A dense thin film electrolyte is then deposited onto the porous anode layer overcoating the anode and filling the anode pores. The substrate foil layer is then removed to allow for exposure of the porous anode/electrolyte to fuel. The cathode is then formed on the electrolyte by depositing a cathode thin film cap using known film deposition techniques. Further processing may be used to increase the porosity of the electrodes. The metal foil may be treated to have an atomically ordered surface, which makes possible an atomically ordered anode and atomically ordered thin film electrolyte for improved performance.Type: ApplicationFiled: May 18, 2006Publication date: September 21, 2006Applicant: Board of Regents, University of HoustonInventors: Xin Chen, Naijuan Wu, Alex Ignatiev, Yuxiang Zhou
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Publication number: 20050151156Abstract: A switchable resistive device has a multi-layer thin film structure interposed between an upper conductive electrode and a lower conductive electrode. The multi-layer thin film structure comprises a perovskite layer with one buffer layer on one side of the perovskite layer, or a perovskite layer with buffer layers on both sides of the perovskite layer. Reversible resistance changes are induced in the device under applied electrical pulses. The resistance changes of the device are retained after applied electric pulses. The functions of the buffer layer(s) added to the device include magnification of the resistance switching region, reduction of the pulse voltage needed to switch the device, protection of the device from being damaged by a large pulse shock, improvement of the temperature and radiation properties, and increased stability of the device allowing for multivalued memory applications.Type: ApplicationFiled: January 13, 2005Publication date: July 14, 2005Inventors: Naijuan Wu, Xin Chen, Alex Ignatiev
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Publication number: 20050090874Abstract: The present invention provides a method for capturing optical micro detectors for improved surgical handling during implantation into an eye comprising the steps of providing an optically active thin film heterostructure on a soluble substrate; forming an array comprising individual optical microdetectors from the optically active thin film heterostructure; attaching the optical microdetector array onto a biodegradable polymer carrier membrane; and separating the optical microdetector array attached to the biodegradable polymer carrier membrane from the soluble substrate thereby capturing the optical microdetectors in the bio-polymer carrier membrane for improved handling of the optical micro-detectors during transfer and implantation into the eye.Type: ApplicationFiled: June 15, 2002Publication date: April 28, 2005Inventors: Naijuan Wu, Ali Zomorrodian
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Publication number: 20040157747Abstract: A thick atomically ordered single buffer layer for use in the integration of high temperature superconductor films with metallic substrates is disclosed. The buffer layer is a doped cerium oxide (CeO2) material, where the doping reduces layer cracking through the modification of thermal expansion coefficient and film strain properties, while adjusting chemical properties and lattice parameters to better match those of the substrate and HTS layer.Type: ApplicationFiled: February 10, 2003Publication date: August 12, 2004Applicant: THE UNIVERSITY OF HOUSTON SYSTEMInventors: Xin Chen, Naijuan Wu, Alex Ignatiev, Yimin Chen
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Patent number: 6762481Abstract: A basic form of a variable capacitive apparatus and its actuating method are disclosed. The apparatus is a simple two-terminal structure and may be set by short duration, low voltage electrical pulses. Materials with perovskite structure or perovskite-related structures, especially colossal magnetoresistive materials, are the active constituents of the apparatus. The apparatus overcomes the shortcomings of its predecessors and offers the advantages of non-volatility, two or multi-level storage, non-destructive reading, free-of-power maintenance and potential high radiation hardness.Type: GrantFiled: October 8, 2002Date of Patent: July 13, 2004Assignee: The University of Houston SystemInventors: Shangqing Liu, Naijuan Wu, Alex Ignatiev, JainRen Li
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Publication number: 20040096572Abstract: A thin film solid oxide fuel cell (TFSOFC) having a porous metallic anode and a porous cathode is provided. The fuel cell is formed by using a continuous metal foil as a substrate to epitaxially deposit a thin film electrolyte on one surface of the foil. The metal foil may then be made porous by photolithographically patterning and etching the other surface of the foil to form holes extending through the foil to the electrolyte/foil interface. The cathode is then formed on the electrolyte by depositing a second thin film using known film deposition techniques. Further processing may be used to increase the porosity of the electrodes. The metal foil may be treated before film deposition to have an atomically ordered surface, which makes possible an atomically ordered thin film electrolyte.Type: ApplicationFiled: November 10, 2003Publication date: May 20, 2004Applicant: UNIVERSITY OF HOUSTONInventors: Xin Chen, Naijuan Wu, Alex Ignatiev