Patents by Inventor Nan Xu

Nan Xu 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).

  • Publication number: 20130060049
    Abstract: A preparation method of (S)-4-hydroxy-2-oxo-1-pyrrolidine acetamide is provided, which includes the steps of preparing the crude product and crystallizing, wherein acetone and water are used as solvents in the step of crystallizing. The (S)-oxiracetam prepared by the method of the present invention has high purity of more than 99.3% and low impurity of 0-0.5%, based on the percentages of the mass. According to the method of the present invention, with regard to the way of charging materials, adding inorganic base only just a few times is easier to handle and more convenient to the industrial manufacturing and application.
    Type: Application
    Filed: September 9, 2010
    Publication date: March 7, 2013
    Inventors: Chao You, Hua Feng, Qi Pang, Lei Ye, Yuying Chen, Zuyuan Rong, Lei Jin, Nan Xu, Fei Li, Bo Li
  • Publication number: 20130049180
    Abstract: A lead frame for a quad flat no-lead (QFN) type semiconductor device package includes a die pad, a plurality of leads that surround the die pad. The outer edge of leads includes a channel that extends from a lower surface to an upper surface of the leads. A semiconductor die is attached to the die pad. An inner edge of each lead is electrically connected to a corresponding bonding pad on the semiconductor die. The assembly is covered with an encapsulation material except that the outer edge of each lead and the corresponding channel are exposed. The channel allows solder to flow up the outer edge of a lead when the QFN device is soldered to a substrate, which improves the ability to perform visual inspection of the solder-lead connection.
    Type: Application
    Filed: July 15, 2012
    Publication date: February 28, 2013
    Applicant: FREESCALE SEMICONDUCTOR, INC
    Inventors: Nan XU, Xingshou PANG, Bin TIAN, Shufeng ZHAO
  • Patent number: 8299967
    Abstract: Antennas for wireless communications based on metamaterial (MTM) structures to arrange one or more antenna sections of an MTM antenna away from one or more other antenna sections of the same MTM antenna so that the antenna sections of the MTM antenna are spatially distributed in a non-planar configuration to provide a compact structure adapted to fit to an allocated space or volume of a wireless communication device, such as a portable wireless communication device.
    Type: Grant
    Filed: May 13, 2009
    Date of Patent: October 30, 2012
    Assignee: Tyco Electronics Services GmbH
    Inventors: Nan Xu, Sunil Kumar Rajgopal, Norberto Lopez, Vaneet Pathak, Ajay Gummalla, Gregory Poilasne, Maha Achour
  • Publication number: 20120238058
    Abstract: A method of assembling semiconductor devices includes placing an array of semiconductor dies on a die support. A cap array structure is provided that has a corresponding array of caps supported by a cap frame structure. The cap array structure and the array of semiconductor dies on the die support are aligned, with the caps extending over corresponding semiconductor dies, in a mold chase. The array of semiconductor dies and the array of caps are encapsulated with a molding compound in the mold chase. The encapsulated units of the semiconductor dies with the corresponding caps are removed from the mold chase and singulated. Singulating the encapsulated units may include removing the cap frame structure from the encapsulated units.
    Type: Application
    Filed: February 16, 2012
    Publication date: September 20, 2012
    Applicant: FREESCALE SEMICONDUCTOR, INC
    Inventors: Junhua LUO, Zhigang BAI, Nan XU, Jinzhong YAO
  • Patent number: 8216886
    Abstract: A method for assembling a semiconductor package includes a rapid cooling step after post mold curing of an encapsulation material. The rapid cooling step includes blowing chilled, compressed air over the package for about two minutes. The rapid cooling step does not require any clamping pressure be simultaneously applied to the package. The rapid cooling step reduces a temperature of the encapsulation material from a curing temperature to the cooled temperature within a maximum period of less than five minutes. By using rapid cooling, as opposed to cooling the package under a clamping pressure with ambient air, package warpage due to CTE mismatches is prevented.
    Type: Grant
    Filed: January 11, 2011
    Date of Patent: July 10, 2012
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Bin Tian, Nan Xu, Jinzhong Yao
  • Patent number: 8128839
    Abstract: The present invention provide a high-luminosity stress-stimulated luminescent material which emits visible light even in daylight, a manufacturing method thereof, and a typical example of the use thereof. The stress-stimulated luminescent material of the present invention satisfies conditions for light emission by at least one of: a luminescence mechanism using static electricity caused by friction; a luminescence mechanism using micro plasma caused by friction; a luminescence mechanism using a piezoelectric effect caused by strain; a luminescence mechanism using lattice defect; and a luminescence mechanism using thermal generation. For example, in case where a base material made of at least one type of aluminate is includes as the stress-stimulated luminescent material, the base material includes a crystal structure with spontaneous polarization, e.g. ?-SrAl2O4, in order to realize the luminescence mechanism using the piezoelectric effect caused by strain.
    Type: Grant
    Filed: April 8, 2005
    Date of Patent: March 6, 2012
    Assignee: National Institute of Advanced Industrial Science & Technology
    Inventor: Chao-Nan Xu
  • Patent number: 8115288
    Abstract: A lead frame for reducing detrimental effects of burr formation includes a lead frame that has leads where a portion of a top surface is removed from a first lead and a portion of a bottom surface is removed from a second lead adjacent to the first lead to reduce spacing between leads while reducing the detrimental effects of burr formation, such as shorting and the like, caused during singulation of a semiconductor device manufactured with the lead frame.
    Type: Grant
    Filed: February 5, 2011
    Date of Patent: February 14, 2012
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Yongsheng Lu, Bin Tian, Nan Xu, Jinzhong Yao, Shufeng Zhao
  • Publication number: 20110293365
    Abstract: A cement plant refractory anchor (10) comprising a body formed of stainless steel, wherein external surfaces of said body have a surface diffusion coating of an iron aluminide phase formed by a high temperature pack cementation process.
    Type: Application
    Filed: December 11, 2009
    Publication date: December 1, 2011
    Applicant: VESUVIUS CRUCIBLE COMPANY
    Inventors: Nick Lebaut, Nan Xu
  • Patent number: 8056422
    Abstract: When visualizing the stress distribution of natural bone, synthetic bone, or a member attached to either thereof without omitted points, in order to measure accurately in a variety of modes using an inexpensive system, a mechanoluminescence material thin film 6 is formed in advance on a bone material peripheral surface 5 in an appropriate area thereof including the portion where an insertion support portion 4 of an artificial hip prosthesis 2 is inserted into a hollow inside 3 of a damaged femur 1 or a synthetic bone simulating the damaged femur. The mechanoluminescence material thin film 6 portion is photographed over its entire circumference with an IICCD camera 7 from the external peripheral side thereof as or after the artificial hip prosthesis 2 is inserted. The obtained image is fed to a computer 11 to obtain a luminescence image 8. The computer 11 outputs the intensities of the received light in the form of an image as is, so that the luminescence image 8 can be obtained easily.
    Type: Grant
    Filed: January 11, 2006
    Date of Patent: November 15, 2011
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Koji Hyodo, Chao-Nan Xu
  • Publication number: 20110248393
    Abstract: A lead frame for reducing detrimental effects of burr formation includes a lead frame that has leads where a portion of a top surface is removed from a first lead and a portion of a bottom surface is removed from a second lead adjacent to the first lead to reduce spacing between leads while reducing the detrimental effects of burr formation, such as shorting and the like, caused during singulation of a semiconductor device manufactured with the lead frame.
    Type: Application
    Filed: February 5, 2011
    Publication date: October 13, 2011
    Applicant: FREESCALE SEMICONDUCTOR, INC
    Inventors: Yongsheng Lu, Bin Tian, Nan Xu, Jinzhong Yao, Shufeng Zhao
  • Publication number: 20110241946
    Abstract: A CRLH antenna device is presented having a hollow cell patch structure.
    Type: Application
    Filed: April 1, 2011
    Publication date: October 6, 2011
    Inventors: Shane Thornwall, Norberto Lopez, Vaneet Pathak, Nan Xu
  • Publication number: 20110227795
    Abstract: Antenna structures and configurations which incorporate alignment keys and support structures which mate Composite Right and Left Handed (CRLH) metamaterial (MTM) structures formed on two or more substrates.
    Type: Application
    Filed: February 1, 2011
    Publication date: September 22, 2011
    Inventors: Norberto Lopez, Nan Xu, Ajay Gummalla, Vaneet Pathak, Maha Achour
  • Patent number: 8006567
    Abstract: A stress history recording system for recording a stress history, which includes a light emitting section including a stress-stimulated luminescent material that emits light in response to a mechanical external force, and a recording section for recording a history of a photoreaction generated due to light emission from the light emitting section. This achieves a technology for recording a stress history by using the stress-stimulated luminescent material.
    Type: Grant
    Filed: March 6, 2007
    Date of Patent: August 30, 2011
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Chao-Nan Xu, Nao Terasaki, Yusuke Imai, Hiroshi Yamada
  • Publication number: 20110193237
    Abstract: A method for assembling a semiconductor package includes a rapid cooling step after post mold curing of an encapsulation material. The rapid cooling step includes blowing chilled, compressed air over the package for about two minutes. The rapid cooling step does not require any clamping pressure be simultaneously applied to the package. The rapid cooling step reduces a temperature of the encapsulation material from a curing temperature to the cooled temperature within a maximum period of less than five minutes. By using rapid cooling, as opposed to cooling the package under a clamping pressure with ambient air, package warpage due to CTE mismatches is prevented.
    Type: Application
    Filed: January 11, 2011
    Publication date: August 11, 2011
    Applicant: FREESCALE SEMICONDUCTOR, INC
    Inventors: Bin Tian, Nan Xu, Jinzhong Yao
  • Publication number: 20110140042
    Abstract: One embodiment of the present invention provides (i) a luminant having a unique crystal structure so as to exhibit high luminosity and (ii) a manufacturing method thereof. Further, the present invention discloses (I) a luminant which exhibits ultraviolet luminescence and (II) a manufacturing method thereof. The inventors developed a stress-stimulated luminescent material which exhibits high luminosity by using a compound having a structure obtained by inserting alkali metal ions and alkali earth metal ions into a base material structure constituted of polyhedral-structure molecules and partially substituting the alkali metal ions and alkaline earth metal ions by rare earth metal ions, transition metal ions, group-III metal ions, or group-IV metal ions.
    Type: Application
    Filed: February 4, 2011
    Publication date: June 16, 2011
    Inventors: Chao-Nan Xu, Hiroshi Yamada
  • Publication number: 20110065240
    Abstract: A lead frame and a method of making a lead frame for a semiconductor package. The lead frame is formed by stamping a lead frame material into a desire configuration. The stamped lead frame is then affixed to a support material. When assembling a semiconductor package using the lead frame, during saw singuation, the saw does not have to cut through much lead frame material. Thus, the saw blade does not wear quickly.
    Type: Application
    Filed: October 13, 2009
    Publication date: March 17, 2011
    Applicant: FREESCALE SEMICONDUCTOR, INC
    Inventors: Xu GAO, Qingchun He, Nan Xu
  • Publication number: 20100248426
    Abstract: A process for assembling a Chip-On-Lead packaged semiconductor device includes the steps of: mounting and sawing a wafer to provide individual semiconductor dies; performing a first molding operation on a lead frame; depositing epoxy on the lead frame via a screen printing process; attaching one of the singulated dies on the lead frame with the epoxy, where the die attach is done at room temperature; and curing the epoxy in an oven. Throughput improvements may be ascribed to not including a hot die attach process. An optional plasma cleaning step may be performed, which greatly improves wire bonding quality and a second molding quality. In addition, since a first molding operation is performed before the formation of epoxy to avoid the problem of the epoxy hanging in the air, the delamination risk between the epoxy and the die is avoided.
    Type: Application
    Filed: March 19, 2010
    Publication date: September 30, 2010
    Applicant: FREESCALE SEMICONDUCTOR, INC
    Inventors: Zhe Li, Qingchun He, Guanhua Wang, Zhijie Wang, Nan Xu
  • Patent number: 7769550
    Abstract: A stress analysis method uses a thermoelastic stress measurement device to measure measuring stress state acting on an object by measuring material temperature state variation caused by stress, a mechanoluminescence measurement device to measure measuring stress state acting on the object by measuring light emitted from mechanoluminescence material according to the stress and an arithmetic processing device to obtain mechanical information, which includes prescribed stress distribution, by performing arithmetic processing on both the measurement data.
    Type: Grant
    Filed: January 11, 2006
    Date of Patent: August 3, 2010
    Assignee: National Institute of Advanced Industrial Science and Technology
    Inventors: Koji Hyodo, Chao-Nan Xu
  • Patent number: 7727817
    Abstract: In a method of packaging a semiconductor IC, a tape is attached to a back surface of a lead frame array, and the lead frame array is held between an upper mold chase and a lower mold chase of a mold, with the back surface of the lead frame array upward. The upper and lower mold chases form an upper cavity and a lower cavity with respect to the lead frame array respectively. A mold compound is injected into the upper and lower cavities respectively. With respect to clearances between leads, between die pads and/or between the leads and the die pads, the mold compound injected into the upper cavity covers the portion of the tape over the clearances before the mold compound injected into the lower cavity fills the clearances, so that the tape is depressed.
    Type: Grant
    Filed: March 13, 2009
    Date of Patent: June 1, 2010
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Xuesong Xu, Nan Xu, Jinzhong Yao
  • Patent number: 7723163
    Abstract: A method of forming a pre-molded lead frame having increased stand-offs includes the steps of attaching a first tape to a first side of the lead frame and a second tape to a second side of the lead frame. The taped lead frame is placed in a mold and a first flow of mold compound is initiated. The first flow of the mold compound fills a space between the first tape and an upper mold chase of the mold. A second flow of the mold compound then is initiated. The second flow of the mold compound fills the spaces between a die pad and leads of the lead frame. The first and second tapes then are removed from the lead frame. Improved stand-offs are provided because the first tape was depressed by the first flow of the mold compound.
    Type: Grant
    Filed: May 26, 2008
    Date of Patent: May 25, 2010
    Assignee: Freescale Semiconductor, Inc.
    Inventors: Xue-song Xu, Zhi-gang Bai, Nan Xu, Jin-zhong Yao