POP-CITY

JungSu CHOI 한국색채학회 2014 International Invitation Exhibition of Color Works Vol.2014 No.-

WalkON Suit: A Medalist in the Powered Exoskeleton Race of Cybathlon 2016

Choi, Jungsu,Na, Byeonghun,Jung, Pyeong-Gook,Rha, Dong-wook,Kong, Kyoungchul IEEE 2017 IEEE robotics & automation magazine Vol.24 No.4

<P>The powered exoskeleton race in Cybathlon 2016 consisted of six challenging tasks that required a pilot with complete paraplegia to walk on a level floor, uphill, downhill, and on stairs; stand up and sit down; step on stones; and even pass through a tilted path. All of these tasks addressed exactly the requirements for a powered exoskeleton designed to assist with activities of daily living (ADL) for paraplegics. Every team brought unique technologies to achieve this goal.</P>

Three-dimensional (3D) palladium-zinc oxide nanowire nanofiber as photo-catalyst for water treatment

Choi, Jungsu,Chan, Sophia,Joo, Hyunjong,Yang, Heejae,Ko, Frank K. Elsevier 2016 Water research Vol.101 No.-

<P><B>Abstract</B></P> <P>Zinc Oxide Nano Wires (ZNWs) has been considered as a promising material for purification and disinfection of water and remediation of hazardous waste owing to its high activity and lower cost. In this study, three-dimensional (3D) structured palladium (Pd)/ZNWs were synthesized on the fabricated electrospun nanofibers and explored for enhancement of organic matter (OM) removal efficiency in water by suppressing electron–hole recombination during photocatalytic activity and increased surface area. The densely populated ZNWs were fabricated on the electrospun nanofiber by electroless plating (EP) and hydrothermal synthesis. In order to improve photocatalytic efficiency, a thin layer of Pd was coated prior to ZNWs growth to induce suppression of electron hole recombination produced during catalyst activity. The creation of a highly porous network of nanofibers decorated with ZNWs resulted in an increase of specific removal rate (SRR) of OM from 0.0249 to 0.0377 mg COD<SUB>Cr</SUB> removed/mg ZNWs-hr when ZNW were grown on a Pd layer. It is believed that the demonstration of OM removal in the water through Pd/ZNWs membrane and enhanced photocatalytic activity under UV irradiation from layered structure can broaden potential applicability of Pd/ZNWs membranes for various photo catalytic water treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> 3D structured ZNWs were uniformly grown on the palladium coated nanofibers. </LI> <LI> Enhancement of OM removal through suppressing electron hole recombination. </LI> <LI> Removal of OM was found to be 96.6% from the Pd/ZNWs nanofiber. </LI> <LI> Pd/ZNWs membrane provide a powerful photocatalyst process for water treatment. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Thermo-sensitive Electrospun Fibrous Magnetic Composite Sheets

Jungsu Choi,Jinu Kim,Heejae Yang,Frank K. Ko,Ki Hyeon Kim 한국자기학회 2015 Journal of Magnetics Vol.20 No.3

The PVDF fibrous composite filled with iron oxide nanoparticles were prepared by using the electrospinning technique. The electrospun composite have the thickness in the range of 60-80 μm with the average fibrous diameters of 500-900 nm. The magnetizations of PVDF fibrous composite filled with iron oxide nanoparticles showed 4.5 emu/g, 3.1 emu/g and 1.6 emu/g at 1.5 T of external magnetic field for 20 wt.%, 10 wt.% and 5 wt.% iron oxide nanoparticles, respectively. The heat elevation of the magnetic composite were measured under various AC magnetic fields, frequency and the ambient temperatures. The temperature reached up to 46.3℃ from 36oC at 128 Oe and 355 kHz for 20 wt.% iron oxide nanoparticles filled in PVDF fibrous composite sheet. The specific absorption rate of theses sheets increased from 0.041 W/g to 0.236 W/g with the increment of AC magnetic field from 90 Oe to 167 Oe at 190 kHz, respectively.

Sleet on the Wind 0129

JungSu CHOI 한국색채학회 2017 International Invitation Exhibition of Color Works Vol.- No.-

ROAD and AUTUMN 1130

JungSu CHOI 한국색채학회 2016 International Invitation Exhibition of Color Works Vol.2016 No.-

MONDAY MORNING 05:20

JungSu CHOI 한국색채학회 2015 International Invitation Exhibition of Color Works Vol.2015 No.-

Palladium-Zeolite nanofiber as an effective recyclable catalyst membrane for water treatment

Choi, Jungsu,Chan, Sophia,Yip, Garriott,Joo, Hyunjong,Yang, Heejae,Ko, Frank K. Elsevier 2016 Water research Vol.101 No.-

<P><B>Abstract</B></P> <P>Zeolite is an exciting natural material due to its unique capability of ammonium nitrogen (NH<SUB>3</SUB> N) adsorption in water. In this study, multifunctional hybrid composites of zeolite/palladium (Ze/Pd) on polymer nanofiber membranes were fabricated and explored for sustainable contaminant removal. SEM and XRD demonstrated that zeolite and palladium nanoparticles were uniformly distributed and deposited on the nanofibers. NH<SUB>3</SUB> N recovery rate was increased from 23 to 92% when palladium coated zeolite was embedded on the nanofiber. Multifunctional nanofibers of Ze/Pd membranes were able to adsorb NH<SUB>3</SUB> N on the zeolites placed on the surface of fibers and palladium catalysts were capable of selective oxidation of NH<SUB>3</SUB> N to N<SUB>2</SUB> gas. The cycling of NH<SUB>3</SUB> N adsorption-oxidation, high flux, hydrophilicity, and flexibility of the membrane makes it a strong candidate for water treatment.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Zeolite and palladium nanoparticles were uniformly deposited on the nanofibers. </LI> <LI> Palladium catalysts were capable of selective oxidation of NH<SUB>3</SUB> N to N<SUB>2</SUB> gas. </LI> <LI> Multifunctional nanofibrous membranes were able to absorb and remove NH<SUB>3</SUB> N. </LI> <LI> Ze/Pd nanofiber membrane can be recycled and reused for NH<SUB>3</SUB> N removal. </LI> <LI> Recovery rate of Ze/Pd membranes functions were shown to be 92.2% at 250 °C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Metabolic tumor volume and total lesion glycolysis predict tumor progression and survival after salvage surgery for recurrent oral cavity squamous cell carcinoma

Choi, Woo Ri,Oh, Jungsu S.,Roh, Jong‐,Lyel,Kim, Jae Seung,Oh, Inhye,Choi, Seung‐,Ho,Nam, Soon Yuhl,Kim, Sang Yoon J. Wiley 2019 Head & neck Vol.41 No.6

<P><B>Abstract</B></P><P><B>Background</B></P><P>This study evaluated the prognostic role of Fluorine 18‐fluorodeoxyglucose positron emission tomography/CT (<SUP>18</SUP>F‐FDG PET/CT) parameters quantitatively measured in patients with recurrent oral cavity cancer.</P><P><B>Methods</B></P><P>Cox proportional hazards regression analyses were used to assess the associations between quantitative <SUP>18</SUP>F‐FDG PET/CT parameters and other clinicopathological factors and progression‐free survival (PFS) and overall survival (OS).</P><P><B>Results</B></P><P>All of the <SUP>18</SUP>F‐FDG PET parameters (SUV<SUB>max</SUB>, SUV<SUB>mean</SUB>, SUV<SUB>peak</SUB>, metabolic tumor volume [MTV], and total lesion glycolysis [TLG]) were significantly associated with poor PFS and OS outcomes after salvage treatment (<I>P</I> < .01). In multivariate analyses, Karnofsky performance score, recurrence site, MTV, and TLG were independent variables predictive of both PFS and OS (<I>P</I> < .05). High MTV (>8.8 mL) or TLG (>29.4 g) values at recurrent lesions were associated with >5‐fold increased risk for tumor progression and mortality after salvage surgery.</P><P><B>Conclusions</B></P><P>The PET parameters of MTV and TLG measured at recurrent lesions may predict tumor progression and survival after salvage treatment.</P><P><B>Condensed Abstract</B></P><P>This study examined the role of <SUP>18</SUP>F‐FDG PET/CT at recurrent staging for predicting tumor progression and survival in 71 consecutive patients with recurrent oral cavity squamous cell carcinomas. Of <SUP>18</SUP>F‐FDG parameters, metabolic tumor volume and total lesion glycolysis were independent factors predictive of tumor progression and survival after salvage treatment.</P>

Effect of n-hexane extracted from food wastewater on biological substrate adsorption in wastewater treatment

Choi, Jungsu,Eom, Hanki,Joo, Hyunjong,Kim, Seongcheol Informa UK (Taylor Francis) 2016 Desalination and water treatment Vol.57 No.2

<P>The purpose of this study was to assess the effects of n-hexane contained in food wastewater on biological substrate adsorption (substrate bio-sorption). To achieve the purpose, microbial activity was assessed based on substrate removal characteristics and specific oxygen uptake rates (SOUR) at different concentrations of injected n-hexane. The X-ray photoelectron spectroscopy (XPS) was applied for an overall observation of n-hexane effects on substrate bio-sorption. The result showed that with higher n-hexane levels, the TBOD5 concentrations increased in the effluent, thereby pushing down substrate removal efficiencies. The SOUR values fell from its maximum 86.4-38.6mgO(2)/gMLVSSh, which indicates that microbial activity was affected by n-hexane injection. In addition, the sludge injected with n-hexane was analyzed by XPS, and it was found that carbon elements (especially C-C and C-H) were gradually reduced on the sludge surface. The injection of n-hexane is assumed to inhibit microbial substrate adsorption, consequently reducing extracellular polymeric substances. Therefore, n-hexane needs to be removed sufficiently through a pre-treatment process in food waste-to-resource facilities.</P>