Patents by Inventor Geun Sig Cha

Geun Sig Cha 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).

  • Patent number: 6177417
    Abstract: The present invention relates to a cholanic acid ring based 4-(trifluoroacetyl)phenyl derivatives of the following formula 1, process for preparation and use thereof. The cholanic acid ring based 4-(trifluoroacetyl)phenyl derivatives of the present invention may be used as a host material in the host-guest chemistry, in detail as a material for ion sensors, optical sensors, gas sensors, biosensors, chromatographies, photostimulated ion-binding resins, ion exchange resins and organic reactions. (In the above formula 1, R, R1, R2, R3 and n are defined in the specifications).
    Type: Grant
    Filed: June 22, 1999
    Date of Patent: January 23, 2001
    Inventors: Junho Chu, Hyung Jung Pyun, In Jun Yoon, Jae Ho Shin, Hakhyun Nam, Geun Sig Cha
  • Patent number: 5531870
    Abstract: This invention relates to a process for performing enhanced selectivity potentiometric ion determinations using an asymmetric ion membrane electrode having an asymmetric membrane with a hydrophilic layer fused to an ion-selective layer.
    Type: Grant
    Filed: May 5, 1995
    Date of Patent: July 2, 1996
    Assignee: E. I. Du Pont de Nemours and Company
    Inventor: Geun Sig Cha
  • Patent number: 5417835
    Abstract: A polyimide matrix is employed to form a substance-sensitive membrane which is particularly suited for installation on a solid state sensor. Polyimide, dissolved in a solvent, such as N,N-dimethylformamide, or N-methyl-2-pyrrolidone (polyimide encapsulant), is combined with an ionophore, plasticizer, and a lipophilic additive. The ionophore may be a calcium ionophore, an ammonium ionophore, or any other ionophore. The membrane may also incorporate, or may be covered by, a bioactive agent, such as an enzyme, an immunochemical, bacteria, antibody, virus, or antigen. The plasticizer is one or both of dimethyl phthalate and diethylene glycol dibenzoate. The lipophilic additive may be potassium tetrakis(p-chlorophenyl)borate. The resulting substance-sensitive membrane has electrochemical properties which compare favorably to those of conventional PVC membranes, and exhibit significantly greater adhesion to glasses and semiconductor substrate materials.
    Type: Grant
    Filed: October 14, 1993
    Date of Patent: May 23, 1995
    Assignee: The Board of Regents of The University of Michigan
    Inventors: Richard B. Brown, Geun-Sig Cha
  • Patent number: 5102526
    Abstract: A silicone matrix is employed to form a substance-sensitive membrane which is particularly suited for installation on a solid state sensor. The ionophore may be a potassium ionophore, an ammonium ionophore or any other ionophore. The membrane may be coupled to the molecule of interest through a bioactive agent, such as an enzyme, an immunochemical, bacteria, antibody, virus, or antigen. The resulting substance-sensitive membrane has electrochemical properties which compare favorably to those of conventional PVC membranes, and exhibit significantly greater adhesion to glasses and semiconductor substrate materials. The improved adhesion will prolong the life of the sensors and prevent the formation of electrolyte shunts which have been known to render solid state sensors inoperative.
    Type: Grant
    Filed: May 2, 1990
    Date of Patent: April 7, 1992
    Assignee: The University of Michigan
    Inventors: Richard B. Brown, Geun-Sig Cha