• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.278-279
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• 2001

최근 건강에 대한 관심이 고조되면서 가정용 진단기, 혹은 재택진료 등의 가능성이 커지고 있다 혈중 성분, 또는 생체 시료와 빛의 상호작용에 관한 연구는 비침습적 정량분석, 또는 생체 조직의 상태 분석의 가능성을 의미하므로 다양한 분야에서 연구가 진행되고 있다. 특히 원적외선(8~15$\mu$m)영역에서의 생체 시료 및 성분들의 특별한 흡수 spectrum등이 보고되면서, 이 영역에서의 정량적인 분석과 영상에 관한 연구가 큰 주목을 받고 있다. (중략)

• Korean Chemical Engineering Research
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• v.55 no.6
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• pp.854-860
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• 2017

PSf/D2EHPA/CNTs beads were prepared by immobilizing extractant di-(2-ethylhexyl)- phosphoric acid (D2EHPA) and adsorbent carbon nanotubes (CNTs) on polysulfone (PSf), and the adsorption characteristics of Sr(II) on the beads were studied. The morphological characteristics of the prepared PSf/D2EHPA/CNTs beads were observed by scanning electron microscopy (SEM), thermo gravimetric analysis (TGA), and Fourier transform infrared spectrometer (FTIR). The equilibrium time for the removal of Sr(II) by PSf/D2EHPA/CNTs beads was 60 min. The experimental kinetic data followed pseudo-second-order model more than pseudo-first-order kinetics model. The maximum removal capacity of Sr(II) obtained from Langmuir isotherm was 4.75 mg/g. The removal efficiencies of Sr (II) by PSf/D2EHPA/CNTs beads were improved 2.5 times by adding the adsorbent CNTs more than by using only the extractant D2EHPA.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.2
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• pp.273-279
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• 2004

Recently, newly developed single high-intensity LED curing lights for composite resins are claimed to have a higher intensity than previous LED curing lights and to results in optimal properties and short curing time. The purpose of this study was to determine the curing effectiveness of the curing units and to evaluate the relationship between the degree of polymerization and distance from curing light tip end to resin surface. One composite resin was tested(Filtek Z250). Thin film specimens were cured with a LED curing unit(Elipar Freelight 2, 10s), Plasma Arc curing unit(Flipo, 6s), Halogen curing light(XL3000, 20s) at four curing light tip to the resin surface(0mm, 2mm, 4mm, 6mm). Degree of conversion of composite resins were determined by a Fourier Transform Infrared Spectrometer(FTIR). From the present study, the following results were obtained. 1. In all curing units, relative light intensity was significantly decreased according to the increase of distance of light tip to the resin surface(p<0.05). LED curing units showed a higher percentile decrease in intensity than other curing units. 2. In all curing units, degree of conversion was decreased as increase of the distance but no statistically significant difference(p>0.05) except between 4mm and 6mm(p<0.05). 3. When comparing degree of conversion of light curing units at each distance(0mm, 2mm, 4mm, 6mm), LED curing light had a higher degree of conversion than plasma arc and halogen curing lights at 0, 2, 4mm(p<0.05). At 6mm, there was a no significant difference among the curing units(p>0.05).

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2642-2646
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• 2012

Pretreatment of spent FCC catalyst and its application in remove trace olefins in aromatics were investigated in this research. The most effective pretreatment route of spent FCC catalyst was calcining at $700^{\circ}C$ for 1 h, washing with 5% oxalic acid solution in ultrasonic reactor and dried. Treated spent FCC catalyst was modified with metal halides, then to prepare catalyst to remove trace olefins in aromatics. X-ray diffraction, Pyridine-FTIR, $N_2$ adsorption-desorption and inductively coupled plasma optical emission spectrometer (ICP-OES) were used to investigate the pretreatment process. The result showed that the performance of the treated spent FCC catalyst was much greater than that of the spent FCC catalyst, which indicted the possibility and improvement of this research.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.128.1-128.1
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• 2011

In amorphous silicon and crystalline silicon(a-Si:H/c-Si) heterojuction solar cells, intrinsic hydrogenated amorphous silicon(a-Si:H) films play an important role to passivate the crystalline silicon wafer surfaces. We have studied the correlation between the surface passivation quality and nature of the Si-H bonding at the a-Si:H/c-Si interface. The samples were obtained by VHF-CVD under different deposition conditions. The passivation quality and analysis of all structures studied was performed by means of quasi steady state photoconductance(QSSPC) methods and fourier transform infrared spectrometer(FTIR) measurements respectively.

• Macromolecular Research
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• v.17 no.6
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• pp.403-410
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• 2009

Cytotoxicity is a severe problem of cadmium sulfide nanoparticles(CSNPs) for use in biological systems. In the present study, mercaptoacetic acid-coated CSNPs were conjugated with bovine serum albumin (BSA) to improve biocompatibility. The surface properties of the CSNPs and albumin-conjugated CSNPs (ACSNPs) were characterized by XRD, UV, FTIR, EA, TEM and DLS. Human breast cancer cells (KB cells) were then cultured in the presence of the nanoparticles to evaluate the cytotoxicity of CSNPs and ACSNPs. Finally, the fluorescence intensity of the nanoparticles' aqueous solution was examined using a fluorescence spectrometer. The results showed that the cell compatibility and fluorescence intensity of ACSNPs were higher than those of CSNPs. The strongly luminescent features of the biocompatible ACSNPs are promising for use in biological fields such as cellular labeling, intracellular tracking and molecular imaging.

• Proceedings of the Korean Fiber Society Conference
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• 1997.10a
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• pp.126-130
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• 1997

A series of Thermoplastic polyurethane elastomers was prepared via a two-step polymerization process. The NCO/OH feed ratio of polyurethane synthesized in this study was varied from 1 to 1.3. Studies have been made on the effects of chemical and physical cross-linkina, and the properties of thermoplastic polyurethane elastomers based on isophorone diisocyanate (IPDI)/1,4-butanediol (BD)/poly(propylene glycol) (PPG, MW:2000), isophorone diisocyanate (IPDI)/BD /poly(oxytetramethylene) glycol (PTMG, MW:2000) was compared. These materials were characterized using FTIR spectrometer, dynamic mechanical thermal analyzer, and tensile retraction tester. PTMG based polyurethane elastomers showed higher elasomeric behavior than PPG based polyurethane elastomers at the same NCO/OH ratio. This feature has been connected with the specific nature of the polyols. The permanent set(%) was decreased with increasing maximum elongation from 50% to 300%.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.410-418
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• 2016

In this study, we prepared electrically conducting composites using epoxy resin of diglycidyl ether of bisphenol A (DGEBA) as a matrix, triethylenetetramine (TETA) as a hardener and nickel powder or multi-walled carbon nanotubes (MWCNTs) grafted with $-NH_2$ groups (MWCNT-$NH_2$) as electrically conducting fillers. Electrical conductivity of composite films were measured by coating on the slide glass with a doctor blade. We measured modification reactions of MWCNT and reaction of MWCNT-$NH_2$ with DGEBA epoxy resin by fourier transform infrared spectrometer (FTIR), thermogravimetric analyzer (TGA) and elemental analyzer (EA). Morphology of composites was investigated by scanning electron microscope (SEM) and sheet resistances of composites were measured by 4-point probe. We found $(9.87{\pm}1.09){\times}10^4{\Omega}/sq$ of sheet resistance for epoxy composite containing both 40 wt% nickel powder and 0.5 wt% of MWCNT-$NH_2$ as fillers, equivalent to epoxy composite containing 53.3 wt% nickel powder only as a filler.

• Polymer(Korea)
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• v.36 no.2
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• pp.216-222
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• 2012

We synthesized microcapsule absorbent with crosslinked poly(styrene-$alt$-maleic anhydride) (PSMA) as a core and PSMA as a shell by a precipitation polymerization method for the delayed absorption of excess water in cement mortar. cPSMA-PSMAs with core-shell structure were synthesized with ratios of 1/1, 1/2 and 1/3 as core monomer mass to shell monomer mass to control shell thickness. We observed the hydrolysis of PSMA in cement-saturated aqueous solution by a FTIR spectrometer. We observed good core-shell structure microcapsules for 1/2(cPSMA #3), but observed incomplete core-shell structure for 1/1(cPSMA #2) and 1/3(cPSMA #4) of core/shell monomer ratios. The swelling ratio of cPSMA #3 in cement-saturated aqueous solution was increased until 20 min. After that it was decreased until 2 hrs swelling time, and they started to increase again. The viscosities of cement paste with cPSMA #3 microcapsules were very slowly increased until 1 hr and increased fast after 1.5 hrs. Cement mortar with 0.5 wt% cPSMA #1 having only core part showed about 5% increase in compressive strength compared to that of plain cement mortar. cPSMA #3 added cement mortar showed the highest compressive strength with 7% increase.

• Polymer(Korea)
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• v.34 no.6
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• pp.495-500
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• 2010

Crosslinked PI films were synthesized from 4,4'-(hexafluoro isopropylidene)diphthalic anhydride (6FDA) and bis[4-(3-aminophenoxy) phenyl] sulfone(BAPS) with various ratios of the reactive monomer cis-4-cyclohexene-1,2-dicarboxylic anhydride(CDBA). We prepared crosslinked poly(amic acid) (PAA) using a 0.1 wt% Grubbs catalyst as a crosslinking agent. The crosslinked PAA was heat-treated at different temperatures to give PI films. The thermo-mechanical properties and optical transparency of the PI films were investigated. The thermal properties of the PI films were examined using Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry(DSC), thermogravimetric analysis(TGA), thermo-mechanical analysis(TMA), and universal tensile machine(UTM), and their optical transparencies were investigated using UV-vis. spectrophotometry. The thermomechanical properties of the PI films improved with increasing CDBA content. However, the optical transparency of the PI films decreased slightly with increasing CDBA content.