Patents by Inventor Sang H. Lee

Sang H. Lee 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).

  • Passivation of group III-V surfaces
    Patent number: 4871692
    Abstract: A method of passivating a Group III-V compound surface by exposing the surface to a compound A-B, wherein A is an element having a heat of oxide formation greater than the heats of oxide formation of Group III and V elements and B is an element: S, Se, Te or Po.
    Type: Grant
    Filed: September 30, 1988
    Date of Patent: October 3, 1989
    Inventors: Hong H. Lee, Sang H. Lee
  • Time division multiplexer for DTDM bit streams
    Patent number: 4833673
    Abstract: A multiplexer for time division multiplexing a plurality of DTDM bit streams is disclosed. By taking advantage of the fact that the frames comprising each DTDM bit stream are not 100% occupied, the frequency of the higher speed output bit stream can be made equal to the product of the nominal center frequency of the input tributaries and the number of input tributaries. This is accomplished through the positive and negative stuffing of DTDM frames.
    Type: Grant
    Filed: November 10, 1987
    Date of Patent: May 23, 1989
    Assignee: Bell Communications Research, Inc.
    Inventors: Hung-Hsiang J. Chao, Sang H. Lee
  • High speed scrambling at lower clock speeds
    Patent number: 4755987
    Abstract: Circuitry generates a plurality of differently-phased m-sequences (or pseudo-random sequences) for scrambling/descrambling of all tributary data signals at a multiplexer/demultiplexer. By scrambling/descrambling at the tributary levels and thus at the lower tributary clock rates, less complex circuitry can be employed, and by properly selecting the tributary scrambling sequences in accordance with the teachings of this invention, a desired high speed line sequence can be attained.
    Type: Grant
    Filed: June 5, 1987
    Date of Patent: July 5, 1988
    Assignee: Bell Communications Research, Inc.
    Inventors: Pil J. Lee, Sang H. Lee
  • Aluminum oxide-containing metal compositions and cutting tool made therefrom
    Patent number: 4217113
    Abstract: A composition formed from (a.) aluminum oxide and/or a solid solution and/or a multiphase composition of aluminum oxide with one or more other metal oxide(s) and (b.) a metallic alloy and having a microstructure comprising a metallic phase, ceramic phase(s) comprising a reactive metal oxide phase and/or solid solutions containing said oxide, an aluminum oxide phase and/or solid solutions of aluminum oxide with one or more other metal oxides. The metallic alloy contains at least one metal characterized by a .DELTA.G of formation (Gibbs free energy) per mole of oxygen of its oxide that is comparable to or greater than the .DELTA.G of formation (Gibbs free energy) per mole of oxygen of aluminum oxide (133 Kcal/mole oxygen). The grain size of the ceramic phase(s) is less than about 10 microns. Cutting tools formed from these compositions have better operating lives than cutting tools containing tungsten carbide or titanium carbide.
    Type: Grant
    Filed: February 8, 1979
    Date of Patent: August 12, 1980
    Assignee: Massachusetts Institute of Technology
    Inventors: Nam P. Suh, Paul D. Fillion, Sang H. Lee