Patents by Inventor Dae Ki Choi

Dae Ki Choi 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: 9926266
    Abstract: Disclosed are a method for preparing a pure isophthalaldehyde bisulfite adduct free from impurities through a specific purification process, and use thereof as a starting material for polymerizing polybenzimidazole under a mild condition. According to the present disclosure, it is possible to obtain a pure isophthalaldehyde bisulfite adduct free from impurities, such as unreacted materials or byproducts. In addition, it is possible to accomplish industrial mass production of a high-molecular weight polybenzimidazole by using the adduct as a starting material for polymerizing polybenzimidazole under a mild condition in an organic solvent.
    Type: Grant
    Filed: October 12, 2016
    Date of Patent: March 27, 2018
    Assignee: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY
    Inventors: Hyoung-Juhn Kim, Eun Ki Kim, So Young Lee, Jong Hyun Jang, Jin Young Kim, Sung Jong Yoo, Dirk Henkensmeier, Dae Ki Choi, Jonghee Han, Suk Woo Nam
  • Publication number: 20180050984
    Abstract: Disclosed are a method for preparing a pure isophthalaldehyde bisulfite adduct free from impurities through a specific purification process, and use thereof as a starting material for polymerizing polybenzimidazole under a mild condition. According to the present disclosure, it is possible to obtain a pure isophthalaldehyde bisulfite adduct free from impurities, such as unreacted materials or byproducts. In addition, it is possible to accomplish industrial mass production of a high-molecular weight polybenzimidazole by using the adduct as a starting material for polymerizing polybenzimidazole under a mild condition in an organic solvent.
    Type: Application
    Filed: October 12, 2016
    Publication date: February 22, 2018
    Inventors: Hyoung-Juhn KIM, Eun Ki KIM, So Young LEE, Jong Hyun JANG, Jin Young KIM, Sung Jong YOO, Dirk Henkensmeier, Dae Ki CHOI, Jonghee HAN, Suk Woo NAM
  • Patent number: 9214692
    Abstract: Provided is poly(benzimidazole-co-benzoxazole) having polybenzimidazole to which benzoxazole units are introduced, as a polymer electrolyte material. The polymer electrolyte material has both high proton conductivity and excellent mechanical properties even when it is obtained by in-situ phosphoric acid doping. The polymer electrolyte material may substitute for the conventional phosphoric acid-doped polybenzimidazole in a polymer electrolyte membrane fuel cell, particularly in a high-temperature polymer electrolyte membrane fuel cell.
    Type: Grant
    Filed: February 7, 2013
    Date of Patent: December 15, 2015
    Assignee: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY
    Inventors: Hyoung-Juhn Kim, Eun Ae Cho, Jong Hyun Jang, Dae Ki Choi, Chang Won Yoon, Suk-Woo Nam, Dirk Henkensmeier, Tae Hoon Lim
  • Publication number: 20150303507
    Abstract: By forming a structure wherein an oxygen ionic conductor or a mixed ionic-electronic conductor (MIEC) on a cathode surface is not covered by a molten carbonate electrolyte using an oxygen ionic conductor or a mixed ionic-electronic conductor having poor wettability on the molten carbonate electrolyte, a new electrochemical reaction site may be provided in addition to that provided by the molten carbonate electrolyte. As a result, cell performance, particularly cathode performance, can be improved even at low operation temperatures (e.g., 500-600° C.).
    Type: Application
    Filed: November 23, 2014
    Publication date: October 22, 2015
    Applicant: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY
    Inventors: Sung Pil YOON, Suk Woo NAM, Chang Won YOON, Tae Hoon LIM, Dae Ki CHOI, Sun-Hee CHOI, Jonghee HAN, Hyung Chul HAM, Hoang Viet Phuc Nguyen
  • Publication number: 20120231364
    Abstract: Provided is a cathode for molten carbonate fuel cells, including a porous nickel-based electrode containing nickel particles, and metal particles coated on the electrode, wherein at least a part of the metal particles are attached to the surface of the nickel particles. A method for preparing the same is also provided. The cathode for molten carbonate fuel cells accelerates the cathodic oxygen reduction and reduces polarization resistance occurring at the cathode, thereby providing a fuel cell with improved performance even at low temperature. Additionally, it is possible to improve the service life of a molten carbonate fuel cell due to such low operation temperature.
    Type: Application
    Filed: January 19, 2012
    Publication date: September 13, 2012
    Applicant: KOREA INSTITUTE OF SCIENCE AND TECHNOLOGY
    Inventors: Jong Hee HAN, Shin Ae SONG, Sung Pil YOON, Suk Woo NAM, Tae Hoon LIM, In Hwan OH, Dae Ki CHOI, Seong Ahn HONG, Chang Won YOON
  • Patent number: 7709126
    Abstract: Disclosed is a micro power cell capable of being applied as an energy source and utilizing a streaming potential phenomenon occurring in accordance with an electrokinetic principle when an electrolyte aqueous solution flows in the microchannels piled up in several layers. The streaming potential cell consists of a PDMS microfluidic-chip fabricated by MEMS process as well as micromachining technology. The microfluidic-chip is formed with multi microchannels radially arranged in parallel with each other around a center of a disk at a regular interval. The disk type multi microchannel can achieve uniform inflow and outflow effects. According to the invention, there is provided a cell device comprising a pile-up chip having a number of disk type microfluidic-chips with the optimal structure of flow-in and flow-out of a fluid, a distributor, a collector, an electrode insertion part, etc.
    Type: Grant
    Filed: January 31, 2006
    Date of Patent: May 4, 2010
    Assignee: Korea Institute of Science and Technology
    Inventors: Myung-Suk Chun, Min Suk Shim, Dae Ki Choi