• Preventive Nutrition and Food Science
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• v.15 no.4
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• pp.282-286
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• 2010

To isolate a calcium-binding peptide from chlorella protein hydrolysates, chlorella protein was extracted and hydrolyzed using Flavourzyme, a commercial protease. The degree of hydrolysis and calcium-binding capacity were determined using trinitrobenzenesulfonic acid and orthophenanthroline methods, respectively. The enzymatic hydrolysis of chlorella protein for 6 hr was sufficient for the preparation of chlorella protein hydrolysates. The hydrolysates of chlorella protein were then ultra-filtered under 5 kDa as molecular weight. The membrane-filtered solution was fractionated using ion exchange, reverse phase, normal phase chromatography, and fast protein liquid chromatography to identify a calcium-binding peptide. The purified calcium-binding peptide had a calcium binding activity of 0.166 mM and was determined to be 700.48 Da as molecular weight, and partially identified as a peptide containing Asn-Ser-Gly-Cys based on liquid chromatography/electrospray ionization tandem mass spectrum.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.1
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• pp.17-21
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• 2003

It has been difficult to characterize the value of treated sapphires for gem stones with bare eyes. Color enhancing treatments by diffusion and annealing became sophisticated and customers and gemologists had asked a non-destructive and fast characterization method. We suggest that Fourier transformation infra-red (FTIR) offers to characterize the cobalt-doped synthetic sapphires successfully in 3 minutes. Our results imply that FTIR may be employed in jewelry business to identify the treated sapphires in quantitative way.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.482-484
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• 2006

대마에 대한 분석 결과, 인피 섬유의 경우 리그닌 함량은 7.6%로 다른 목질계 바이오매스나 일년생 초본류와 비교하여 매우 낮은 리그닌 함량을 나타냈으며 탄수화물 함량은 65.4%로 목질계 바이오매스와 유사하고, 초본류보다는 오히려 높았다. 목부는 리그닌 및 탄수화물 함량이 활엽수와 유사한 경향을 나타내었는데 특히 높은 자일란의 함량이 확인되었다. 또한 회분 함량이 인피섬유와 목부에서 각각 5.0%와 2.3%로 낮은 값을 나타내어 당화 및 발효 공정에 적용될 때 회분에 의한 공정 장애(스케일링 등)의 가능성을 낮추어 줄 것으로 사료되었다. 최종적으로 이러한 화학적 분석을 통해 대체에너지 생산을 위한 자원으로서 대마의 가능성을 확인할 수 있었다.

• Bulletin of the Korean Chemical Society
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• v.20 no.12
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• pp.1501-1505
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• 1999

Expansion dynamics of C$^{+}$ ions ejected from 355-nm laser ablation of graphite target in vacuum has been investigated by pulsed-field time-of-flight (TOF) mass spectrometry. A strong nonlinear dependence of the amount of desorbed C$^{+}$ ions on laser fluence is interpreted by the mechanism that C$^{+}$ ions are produced directly from the graphite via conversion of the multiphoton energy into thermal energy. The temporal evolution of C$^{+}$ ions was measured by varying the delay time of the ion repelling pulse with respect to the laser irradiation, which provides significant information on the ablated plume characterization. The TOF distributions of ablated ions showed a bimodal shape and could be fitted by shifted Maxwell-Boltzmann distributions. The velocity of the fast component increases with the delay time, whereas the slow component (< 500 m/s) exhibits a constant velocity. Also studied were the effects of the laser fluence on the energetics of C$^{+}$ ions.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.71-72
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• 2019

본 논문에서는 계층구조 합성곱 신경망 기반의 고해상도 동영상 프레임 고속 보간 방법을 제안한다. 기존의 고해상도 동영상 프레임 보간 방법은 시간 해상도와 공간 해상도를 분리하여 보간 하기 때문에, 예측된 보간 프레임이 블러(blur) 열화를 갖는 문제를 보인다. 제안하는 방법에서는 이러한 문제를 해결하기 위하여 계층구조 합성곱 신경망 기반의 보간 방법을 이용한다. 제안하는 계층구조 합성곱 신경망은 우선 저해상도의 광학 흐름 추정지도를 생성하고 이를 고해상도로 복원하여 프레임 보간을 수행한다. 이때, 저해상도 광학 흐름 지도를 추정할 때 사용된 특징 정보들을 활용하여 고품질의 고해상도 광학 흐름 지도를 추정한다. 실험을 통하여 제안하는 방법이 고해상도 프레임을 고속으로 보간하며, 동시에 블러 열화에 대한 성능 향상을 가짐을 보였다.

• Journal of Electrochemical Science and Technology
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• v.12 no.2
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• pp.212-216
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• 2021

We investigated the feasibility of hydrogen storage with electrochemically formed VO₂ nanotubes. The VO₂ nanotubes were fabricated through the anodization of vanadium metal in fluoride ion-containing organic electrolyte followed by an annealing process in an Ar-saturated atmosphere at 673 K for 3 h at a heating rate of 3 K /min. During anodization, the current density significantly increased up to 7.93 mA/cm² for approximately 500 s owing to heat generation, which led to a fast-electrochemical etching reaction of the outermost part of the nanotubes. By controlling the anodization temperature, highly ordered VO₂ nanotubes were grown on the metal substrate without using any binders or adhesives. Furthermore, we demonstrated the hydrogen sorption properties of the anodic VO₂ nanotubes.

• Nuclear Engineering and Technology
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• v.26 no.4
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• pp.461-470
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• 1994

Sorption experiments of $^{60}$ Co, $^{85}$ Sr. and $^{137}$ Cs onto sandstone particles in a batch were carried out to investigate the migration mobility. Sorption kinetics and reversibility as well as sorption mechanisms were examined. Sorption reaction occurred mostly within 10 hours on the outer surface of the sandstone particle but diffusion into the inner surface of the mineral has still occurred after that time. In order to distinguish sorption types of radionuclides, a sequential chemical extraction was introduced. The sorbed radionuclides were then extracted by applying different solutions of synthetic groundwater, CaCl$_2$, KCl and KOX-HA Especially KCl is adopted to extract the ion-exchanged cesium. Sorption types considered are reversible sorption under groundwater condition, ion exchange, association with ferro-manganese oxides or oxyhydroxides, and irreversible fixation. Strontium sorbs onto the sandstone surface mainly by fast and reversible ion exchange reaction. However, cobalt and cesium do not sorb by simple process. The main sorptive binding of cobalt was the association with ferro-manganese oxides and the secondary one was irreversible fixation. Diffusion into the lattice of minerals controlled the sorption rate of cobalt The main sorptin type of cesium was irreversible fixation, while ion exchange reaction was the secondary importance. Hence the oreder of migration mobility for the three radionuclides was Sr$^{2＋}$ ＞ Co$^{2＋}$ ＞ Cs$^{＋}$ in the sandstones.

• Journal of the Korean Chemical Society
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• v.60 no.2
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• pp.131-136
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• 2016

Copper ion induced photoluminescence (PL) quenching dynamics and recovery of the PL by zinc ions were investigated for CdSe based nanocrystals. When copper ions were added, CdSe quantum dots showed fast and dramatically PL quenching whereas PL of CdSe nanorod gradually decreased. In the presence of zinc ions, the PL of CdSe/CdS (core/shell) nanocrystals that have quenched by copper ions was efficiently recovered. It showed that the PL intensity of nanocrystals increased by 50% in a solution containing 1 μM zinc ions. The PL intensity was increasing with increasing zinc ions, and could be described by Langmuir binding isotherm model. We showcase that the CdSe based nanocrystals can be used as fluorescence turn-on sensor.

• Journal of environmental and Sanitary engineering
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• v.15 no.1
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• pp.25-33
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• 2000

The new ion exchange resin was synthesized from chloromethylated styrene-1,4-divinylbenzene(DVB) with 1-aza-15-crown-5 macrocyclic ligand by substitution reaction. The effect of pH, time, dielectric constant of solvent and cross-linked of the matrix on the adsorption for $UO_2^{2+}$, $Ca^{2}$ and $Lu^{3+}$ was investigated. The metal ion was not adsorbed on the resins below pH 3 but above pH 4 fast adsorption behavior was showed. The optimum equilibrium time for adsorption of metallic ions was two hours. The adsorption selectivity determined in ethanol matrix was in increasing order $UO_2^{2+}>Ca^{2}>Lu^{3+}$. The adsorption power was in the order of 1%, 2%, 10% and 20% -crosslinked resin, but adsorption properties of resins decreased in proportion to the order of dielectric constant of solvents used. In addition, these metal ions could be separated in the column packed with 1% crosslinked resin by pH2.5 $HNO_3$ as an eluent.

• Membrane Journal
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• v.26 no.6
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• pp.458-462
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• 2016

Saline water electrolysis, known as chlor-alkali (CA) membrane process, is an electrochemical process to generate valued chemicals such as chlorine, hydrogen and sodium hydroxide with high purities higher than 99%, using an electrolytic cell composed of cation exchange membrane, anode and cathode. It is necessary to reduce energy consumption per a unit chemical production. This issue can be solved by decreasing intrinsic resistance of the membrane and the electrodes and/or by reducing their interfacial resistance. In this study, the electron radiation grafting of a $Na^+$ ion-selective polymer was conducted onto a hydrocarbon sulfonated ionomer membrane with high chemical resistance. This approach was effective in improving electrochemical efficiency via the synergistic effect of relatively fast $Na^+$ ion conduction and reduced interfacial resistance.