• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.951-959
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• 2009

Most, if not all, Basidiomycetes mushrooms have biologically active polysaccharides showing potent antitumor activity with immunomodulating properties. These polysaccharides have various chemical compositions and belong primarily to the $\beta$-glucan group. In this study, the crude water-soluble polysaccharide HEF-P, which was obtained from the fruiting body of Hericium erinaceus by hot water extraction and ethanol precipitation, was fractionated by DEAE-cellulose and Sepharose CL-6B column chromatographies. This process resulted in four polysaccharide fractions, named HEF-NP Fr I, HEF-NP Fr II, HEF-AP Fr I, and HEF-AP Fr II. Of these fractions, HEF-AP Fr II was able to upregulate the functional events mediated by activated macrophages, such as production of nitric oxide and expression ofcytokines (IL-1${\beta}$ and TNF-${\alpha}$). The molecular mass of HEF-AP Fr II was estimated by gel filtration to be 13 kDa. Its structural characteristics were investigated by a combination of chemical and instrumental analyses, including methylation, reductive cleavage, acetylation, Fourier transform infrared spectroscopy (FT-IR), and gas chromatography-mass spectrometry (GC-MS). Results indicate that HEF-AP Fr II is a low-molecular-mass polysaccharide with a laminarin-like triple helix conformation of a ${\beta}$-1,3-branched-${\beta}$-1,6-glucan.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.37-42
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• 2008

Purpose: This study is to prepare tintable hard coatings for plastic lenses and to evaluate spectroscopic and surface characteristic for these coatings. Methods: These coatings had been prepared by the sol-gel method using TEOS, MTMS and GPTS. Scanning electron microscopy (SEM), Raman spectroscopy, infrared (IR) spectroscopy and UV/VIS spectroscopy have been used to investigate the optical and structural characteristics of the coatings. Results: Tint ability of this coating was about 2 times higher than general hard coatings. The lenses applied by tintable hard coatings showed excellent adhesion, abrasion resistance, hot water resistance, and chemical resistance. Pencil hardness was 5H and the surface of coatings was smooth and free of cracks. Conclusions: This hard coating system for plastic lenses offered a hard and stable surface that could be tinted.

• Journal of Microbiology and Biotechnology
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• v.21 no.10
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• pp.1036-1042
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• 2011

The exopolysaccharide botryosphaeran ($EPS_{GLC}$; a ($1{\rightarrow}3$)($1{\rightarrow}6$)-${\beta}$-D-glucan from Botryosphaeria rhodina MAMB-05) was sulfonated to produce a water-soluble fraction ($EPS_{GLC}$-S) using pyridine and chlorosulfonic acid in formamid. This procedure was then repeated twice to produce another fraction ($EPS_{GLC}$-RS) with a higher degree of substitution (DS, 1.64). The purity of each botryosphaeran sample (unsulfonated and sulfonated) was assessed by gel filtration chromatography (Sepharose CL-4B), where each polysaccharide was eluted as a single symmetrical peak. The structures of the sulfonated and re-sulfonated botryosphaerans were investigated using ultraviolet-visible (UV-Vis), Fourier-transform infrared (FT-IR), and $^{13}C$ nuclear magnetic resonance ($^{13}C$ NMR) spectroscopies. $EPS_{GLC}$ and $EPS_{GLC}$-RS were also assayed for anticoagulation activity, and $EPS_{GLC}$-RS was identified as an anticoagulant.

• Korean Journal of Materials Research
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• v.12 no.2
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• pp.117-120
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• 2002

We investigated the possibility of direct bonding of the Si ∥SiO$_2$/Si$_3$N$_4$∥Si wafers for Oxide-Nitride-Oxide(ONO) gate oxide applications. 10cm-diameter 2000$\AA$-thick thermal oxide/Si(100) and 500$\AA$-Si$_3$N$_4$LPCVD/Si (100) wafers were prepared, and wet cleaned to activate the surface as hydrophilic and hydrophobic states, respectively. Cleaned wafers were premated wish facing the mirror planes by a specially designed aligner in class-100 clean room immediately. Premated wafer pairs were annealed by an electric furnace at the temperatures of 400, 600, 800, 1000, and 120$0^{\circ}C$ for 2hours, respectively. Direct bonded wafer pairs were characterized the bond area with a infrared(IR) analyzer, and measured the bonding interface energy by a razor blade crack opening method. We confirmed that the bond interface energy became 2,344mJ/$\m^2$ when annealing temperature reached 100$0^{\circ}C$, which were comparable with the interface energy of homeogenous wafer pairs of Si/Si.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.62.2-62.2
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• 2011

산업화 이후, 석탄 석유를 중심으로 한 화석연료가 이산화탄소를 대량으로 배출하며 지구 온난화를 야기함에 따라, 기존의 화석연료를 대체할 청정하고 무한 재생 가능한 대체에너지로 가장 큰 기대를 받고 있는 것은 태양에너지이며, 이에 보조를 맞춰 태양광발전에 대한 연구개발이 국내외적으로 활발히 진행되고 있는 실정이다. 태양 전지는 빛 에너지를 직접 전기 에너지로 바꿔주는 소자로, 셀의 효율을 높이기 위해서는 최대한 많은 빛을 흡수시킬 수 있는 것이 중요하다. 빛의 반사를 줄이는 방법에는 texturing과 antireflecting coating이 있다. Antireflecting coating은 반도체와 공기의 중간 굴절율을 갖는 박막을 증착하여 측면 반사를 감소시킴으로서 빛의 손실을 감소시키는 역할을 한다. 과거에 반사방지막으로 가장 많이 사용되었던 물질은 SiO로써 굴절률은 1.8~1.9로서 최소의 반사율은 1% 미만이지만, 가시광선영역에서의 흡수에 의한 손실이 생기므로, SiNx가 대체 물질로 제안되었다. SiNx의 경우 굴절률이 약 1.5로서 Si에 쉽게 형성시킬 수 있고, texturing된 Si 표면에 적합하며 반사율을 10%에서 2%로 줄일 수 있는 장점을 가지고 있다. 따라서 본 연구에서는 high power, high frequency PECVD 방법으로 $SiH_4$와 $NH_3$ gas의 비율, $N_2$ carrier gas 등 공정 변수를 변화시켜 증착한 SiNx 박막의 결정학적 특성을 X-ray diffraction 분석과 XPS (X-ray photoelectron spectroscopy)를 통해 화학적 결합을 확인하였고, 이를 FT-IR (Fourier Transform-Infrared spectroscopy)를 통해 관찰한 결과와 연관시켜 분석하였다. 굴절율의 경우 ellipsometer를 이용하여 측정하였으며 위의 측정을 통하여 SiNx박막의 반사 방지막으로써의 가능성을 확인 하였다.

• Polymer(Korea)
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• v.34 no.1
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• pp.69-73
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• 2010

Effects of reaction time and temperature on the isomerization and dehydrobromination reactions of brominated butyl rubber were investigated. The structural composition of brominated butyl rubber was determined by Fourier transform infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy($^1H$-NMR), Density functional theory (DFT) was used to study on the isomerization and dehydrobromination mechanisms of model compounds. The geometries for model compounds of 3-bromo-5,5,7,7-tetramethyl-2(2',2',4',4'-tetramethyl)pentyl-1-octylene (3BrOE), 1-bromo-5,5,7,7-tetramethyl-2(2',2',4',4'-tetramethyl)pentyl-2-octylene (1Br2OE) and 5,5,7,7-tetramethyl-2(2',2', 4',4'-tetramethyl)pentyl-1,3-octadiene (CD) had been optimized by using density functional theory at B3LYP/3-21G and B3LYP/6-31G levels. The predicted energy of 3BrOE lies higher than that of 1Br2OE which suggests that 1Br2OE configuration is more stable than the 3BrOE configuration. Compared with the energy barrier, the pathway of dehydrobromination is less competitive than that of isomerization. This is qualitatively consistent with the experimental results.

• Polymer(Korea)
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• v.37 no.3
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• pp.332-341
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• 2013

H-shaped amphiphilic pentablock copolymers $(PSt)_2-b-PCL-b-PEO-b-PCL-b-(PSt)_2$ was synthesized via chemoenzymatic method by combining enzyme-catalyzed ring-opening polymerization (eROP) of ${\varepsilon}$-caprolactone (${\varepsilon}$-CL) and atom transfer radical polymerization (ATRP) of styrene. By this process, we obtained copolymers with controlled molecular weight and low polydispersity. The structure and composition of the obtained copolymers were characterized by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC) and infrared spectroscopy analysis (IR). The crystallization behavior of the copolymers was analyzed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The crystallization behavior of the H-shaped block copolymers demonstrated a PCL dominate crystallization. The self-assembly behavior of the copolymers was investigated in aqueous media. The hydrodynamic diameters of the copolymer micelles in aqueous solution were measured by dynamic light scattering (DLS). The morphology of the copolymer micelles was observed by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The hydrodynamic diameters of spherical micelles declined gradually with the increase of the hydrophobic chain lengths of the copolymers. The critical micelle concentration (CMC) values were determined from fluorescence emission, and it was found that the CMCs decreased with an increase of PSt hydrophobic block lengths.

• Journal of the Korean Wood Science and Technology
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• v.48 no.3
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• pp.303-314
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• 2020

Gambir is a non-wood forest product with a potential of being used as wood adhesive, due to about 33% catechin in it. Meanwhile, catechins and sucrose have not been studied as adhesives. Therefore, basic characteristics of gambir-sucrose adhesives were investigated. In this research, adhesives were prepared by dissolving gambir and sucrose in distilled water, at different blending ratios of the gambir/sucrose such as 100/0, 75/25, 50/50, and 25/75 wt%. Furthermore, gas chromatography-mass spectrometry (GC-MS) was employed to determine the gambir chemical compositions, and Fourier transform-infrared (FTIR) spectroscopy was carried out to identify chemical bonds. Particleboards with a target density of 0.8 g/㎤ were then manufactured by hot-pressing for 10 min at 200℃. The internal bond (IB) strength of particleboard was subsequently measured. Based on the GC-MS analysis, 31.11% of catechin was identified. In addition, the viscosity, density, solid content, and gelation time of the adhesives, and insoluble matter content (IMC) in boiling water were 7.30~33.24 mPa.s, 1.2~1.3 g/㎤, 25.56~28.44%, 73~420 min, and 29.75~62.10%, respectively. Adding sucrose to the adhesive was observed to raise the IMC from 49.05 to 62.10%, at 180℃ and 200℃. FT-IR analysis showed that the gambir absorption peaks occurred at approximately 1620 cm^-1, assigned to the C=O stretching of 5-hydroxymethylfurfural, which tended to increase with the addition of sucrose. The reaction between gambir and sucrose was observed in the form of the dimethylene ether bridge. The 25/75 wt% gambir-sucrose adhesives and 200℃ hot-pressed temperature resulted in the highest IB strength (0.89 MPa), and met the requirement of JIS A5908-2003 type 18. Consequently, the gambir-sucrose adhesive could be used as a particleboard adhesive.

• Tribology and Lubricants
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• v.30 no.4
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• pp.224-233
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• 2014

We prepared polyester-polyamines to improve the effect of carbon black dispersibility for use in thermal transfer ink, and synthesized polymeric dispersing agents by two-step reactions. In the first step, we made polyester by polycondensing 1,6-hexanediol and adipic acid. The resulting polymers had carboxylic acid, which was linked with polyamine via an acid-base reaction. We then characterized the polyester-polyamine structure by NMR spectroscopy and Fourier transform infrared spectroscopy (FT-IR). We also determined the basic characterizations such as total acid numbers (TAN) (5.0-67.5 mgKOH/g), hydroxyl values (27.1-67.5 mgKOH/g), and molar masses ($M_n=1.6-8.4kg\;mol^{-1}$) for the polyester and total base numbers (TBN) (15.3-57.1 mgKOH/g), hydroxyl values (33.0-79.8 mgKOH/g), and nitrogen contents (1.02-3.48%) for the polyester-polyamine polymers. We thus prepared thermal transfer ink using carbon blacks and the polyester-polyamine dispersing agents, and evaluated the resulting mixtures for printability, adhesive force, storage stability, ink appearance, ink gloss, and processability. These mixtures showed significant dispersibility for carbon black in the ink. Thus, we concluded that the dispersibility of the polymeric materials depended on the polyamine structure and the hydrophilicity-hydrophobicity distribution of the polymeric dispersants.

• Journal of the Optical Society of Korea
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• v.15 no.4
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• pp.386-393
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• 2011

In this study, we report an effective k-domain linearization method with a pre-calibrated indexed look-up table. The method minimizes k-domain nonlinear characteristics of a swept source optical coherence tomography (SS-OCT) system by using two arrays, a sample position shift index and an intensity compensation array. Two arrays are generated from an interference pattern acquired by connecting a Fabry-Perot interferometer (FPI) and an optical spectrum analyzer (OSA) to the system. At real time imaging, the sample position is modified by location movement and intensity compensation with two arrays for linearity of wavenumber. As a result of evaluating point spread functions (PSFs), the signal to noise ratio (SNR) is increased by 9.7 dB. When applied to infrared (IR) sensing card imaging, the SNR is increased by 1.29 dB and the contrast noise ratio (CNR) value is increased by 1.44. The time required for the linearization and intensity compensation is 30 ms for a multi thread method using a central processing unit (CPU) compared to 0.8 ms for compute unified device architecture (CUDA) processing using a graphics processing unit (GPU). We verified that our linearization method is appropriate for applying real time imaging of SS-OCT.