• Carbon letters
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• 제25권
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• pp.1-13
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• 2018

Gold functionalized graphene oxide (GOAu) nanoparticles were reinforced in acrylonitrile-butadiene rubbers (NBR) via solution and melt mixing methods. The synthesized NBR-GOAu nanocomposites have shown significant improvements in their rate of curing, mechanical strength, thermal stability and electrical properties. The homogeneous dispersion of GOAu nanoparticles in NBR has been considered responsible for the enhanced thermal conductivity, thermal stability, and mechanical properties of NBR nanocomposites. In addition, the NBR-GOAu nanocomposites were able to show a decreasing trend in their dielectric constant (${\varepsilon}^{\prime}$) and electrical resistance on straining within a range of 10-70%. The decreasing trend in ${\varepsilon}^{\prime}$ is attributed to the decrease in electrode and interfacial polarization on straining the nanocomposites. The decreasing trend in electrical resistance in the nanocomposites is likely due to the attachment of Au nanoparticles to the surface of GO sheets which act as electrical interconnects. The Au nanoparticles have been proposed to function as ball rollers in-between GO nanosheets to improve their sliding on each other and to improve contacts with neighboring GO nanosheets, especially on straining the nanocomposites. The NBR-GOAu nanocomposites have exhibited piezoelectric gauge factor (${GF_{\varepsilon}}^{\prime}$) of ~0.5, and piezo-resistive gauge factor ($GF_R$) of ~0.9 which clearly indicated that GOAu reinforced NBR nanocomposites are potentially useful in fabrication of structural, high temperature responsive, and stretchable strain-sensitive sensors.

• 한국의류산업학회지
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• 제18권6호
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• pp.858-868
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• 2016

This study aims to examine the formative characteristics of seniors' fashion in overseas social media, and look into the psychological characteristics of seniors by analyzing the emotions and the characteristics of psychological mechanism in seniors' fashion. The study methods include statistical analysis and content analysis for literary study and data analysis. For data analysis, statistical and content analyses were conducted to analyze 992 data collected from Advanced style, Facebook, and Instagram for 4 years from 2013 to 2016. In formative features shown at overseas social media, circle and square silhouette, achromatic color and warm color, showy tone color, soft material, horizontal details, plain and natural patterns, cap and sunglasses production, and sophisticated elegance styles appeared high. The emotional characteristics in senior's fashion had a silhouette that expressed stability, color that expressed passion, love, happiness, joy, hope and comfort. Materials were expressed by the emotions of dependence and attachment, details were expressed by stable, maternal, calm, comfortable and harmonious emotions. Patterns were expressed by the images of beauty, love, fruit and psychological stability. Accessories were expressed by young and characterful images. Style expressed the emotions of trust, pride, longing, intoxication and ecstasy. The characteristics of psychological mechanism used such shapes and patterns as flower, heart and lips to symbolize the emotions of love, humor, and fun. Young and trendy fashion were expressed in compensation for aging. Kitsch and kidult style was expressed by regression. Elegance fashion was expressed by the sublimation of pride, trust and intoxication.

• The Journal of Advanced Prosthodontics
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• 제6권3호
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• pp.207-214
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• 2014

PURPOSE. This study characterized the synthesis of a modified PMMA (Polymethyl methacrylate) denture acrylic loading platinum nanoparticles (PtN) and assessed its bacterial inhibitory efficacy to produce novel antimicrobial denture base material. MATERIALS AND METHODS. Polymerized PMMA denture acrylic disc ($20mm{\times}2mm$) specimens containing 0 (control), 10, 50, 100 and 200 mg/L of PtN were fabricated respectively. The obtained platinum-PMMA nanocomposite (PtNC) was characterized by TEM (transmission electron microscopy), SEM/EDX (scanning electron microscope/energy dispersive X-ray spectroscopy), thermogravimetric and atomic absorption spectrophotometer analysis. In antimicrobial assay, specimens were placed on the cell culture plate, and $100{\mu}L$ of microbial suspensions of S. mutans (Streptococcus mutans) and S. sobrinus (Streptococcus sobrinus) were inoculated then incubated at $37^{\circ}C$ for 24 hours. The bacterial attachment was tested by FACS (fluorescence-activated cell sorting) analysis after staining with fluorescent probe. RESULTS. PtN were successfully loaded and uniformly immobilized into PMMA denture acrylic with a proper thermal stability and similar surface morphology as compared to control. PtNC expressed significant bacterial anti-adherent effect rather than bactericidal effect above 50 mg/L PtN loaded when compared to pristine PMMA (P=.01) with no or extremely small amounts of Pt ion eluted. CONCLUSION. This is the first report on the synthesis and its antibacterial activity of Pt-PMMA nanocomposite. PMMA denture acrylic loading PtN could be a possible intrinsic antimicrobial denture material with proper mechanical characteristics, meeting those specified for denture bases. For clinical application, future studies including biocompatibility, color stability and warranting the long-term effect were still required.

• 한국지반공학회논문집
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• 제37권3호
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• pp.43-50
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• 2021

우리나라는 산지가 많은 지형적인 특성으로 도로와 도시 개발에 따라 산지를 굴착하고 옹벽을 설치하는 공사가 매년 증가하고 있다. 특히 Panel식 옹벽은 안정성이 높기 때문에 사용빈도가 높으며, 일반적으로 Bottom-up방식을 사용하고 있다. 하지만 옹벽을 설치하기 위해 1:0.3정도의 기울기로 굴착 후 옹벽을 시공하는 방식인데 이러한 방식은 경사굴착으로 인해 추가 토공처리가 필요하며, 되메움과 다짐불량에 의한 안정성 저하 등의 문제점을 지니고 있다. Top-down방식의 경우 이러한 문제점을 보완할 수 있다. 하지만 Panel을 사면에 부착시키기 위해 사용되는 모르타르로 인해 옹벽과 사면 사이에 불투수층이 생긴다. 따라서 본 연구에서는 가상의 사면에 불투수층을 고려하여 배수시스템들의 역할이 우기시 사면의 안정성에 미치는 영향에 대하여 비교 분석하였다.

• 대한치과보철학회지
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• 제59권1호
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• pp.55-62
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• 2021

하악은 상악보다 지지 면적이 적고, 특히 전반적인 치조골 흡수가 진행된 환자에서는 혀와 하악골의 움직임으로 인해 통상적인 총의치의 경우 의치의 안정성과 저작 효율이 현저히 낮다. 이러한 환자에 있어 소수의 임플란트를 이용한 임플란트 피개의치는 유지력과 안정성이 높고 발음이나 저작력 면에서도 우수한 예지성 있는 치료방법으로 평가되고 있다. 본 증례에서는 상악의 무치악, 하악의 전반적인 치조골 흡수를 보이는 환자에 있어 상악에는 총의치, 하악에는 4개의 임플란트를 식립하여 milled bar를 이용한 임플란트 피개의치를 제작하였다. 이후 12년 동안 임플란트 주변의 치주조직의 변화를 지속적으로 관리 및 관찰하였고, 변화 사항 및 보철물의 정기적인 관리에 대해서 보고하고자 한다.

• 대한정형외과스포츠의학회지
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• 제7권1호
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• pp.19-23
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• 2008

족관절 만성 외측 불안정증을 비해부학적인 방법으로 재건한 후에 발생하는 여러가지 문제점들을 해결하기 위하여 해부학적으로 재건하는 여러가지 방법이 보고되었다. 해부학적인 위치로 재건하는 것이 정상 관절 역학과 안정성을 회복하는데 중요하다. 해부학적인 재건 방법의 가장 큰 문제점은 인대를 정상적인 주행 방향으로 재건하는 것이 매우 어렵다는 점인데, 저자는 전거비 인대와 종비 인대가 서로 인접하여 위치하므로 두 인대의 비골측 부착부에 한 개의 터널을 만드는 것이 각각의 인대가 통과 할 별도의 터널을 만드는 것보다 좀 더 해부학적이라고 생각하였다. 이 논문에서는 외측 인대의 해부학적 재건에 필요한 기초 지식을 알아보고 반건양건을 이용한 재건 수술 방법을 소개하였다.

• 한국환경과학회지
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• 제16권2호
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• pp.227-232
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• 2007

Water pollution in enclosed water bodies such as lake and river has become a serious problem over the world. Domestic wastewater is responsible for more than 60 % pollution load in public water area in Korea. Effluent of the treated domestic wastewater at low removal level is abundantly fed rivers and lakes and thus be an serious cause of lake pollution. Therefore, effective implement of domestic wastewater treatment in basin of lake and river must be prepared. The septic tank is one of the effective domestic wastewater treatment equipment and used in individual treatment for a unit of household, The purpose of septic tank as biological treatment system is simultaneously to remove BOD, T-N, T-P and reduce turbidity from influent. Accordingly, the appropriate control of functional microorganisms is important subject for the establishment of stability and economy of the biological treatment method. Especially, microanimals as a high-ranked microorganisms of food-chain are important, because microanimals control the other microorganisms especially various bacteria and effect on function of treatment. Therefore, it is necessary that functional predator like rotifers are attached in wastewater treatment process. In this study, the methods for attachment high density the rotifer to and improvement of transparency in the effluence by a dense rotifer was examined using laboratory scale biological treatment reactor simulated septic tank and real one.

• Clinics in Shoulder and Elbow
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• 제2권1호
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• pp.8-13
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• 1999

The results of the operative treatment of the Grade III acromioclavicular joint injury is defined by the durability of the reduced joint and free of exertional pain. Several surgical techniques have been applied to reduce and stabilize the joints effectively. Resection of clavicular lateral end and subacromial decompression also could be applied to prevent post-operative arthritic change. Biomechanical studies reveals the role of clavicular elevation and rotation to achieve more than 90 degrees of elevation. It also serves as a attachment site of deltoid and trapezius muscle. The stability and mobility of the both acromioclavicular and coracoclavicular joint are important to get full functional recovery. We modified the methods of coracoacromial ligament transfer described by Weaver-Dunn and by Shoji et a!. to pre­vent pullout of the transferred ligament and to get more improved functional results. Main technical point was harvesting full thickness bone block and fix it through the key-hole to reduce pull out angle.

• 환경위생공학
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• 제10권3호
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• pp.67-77
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• 1995

This study was performed for minimization of excessive biofilm effects at the high strength organic wastewater treatment. As a results of biofilm attachment experiment using piggery wastewater, aggravation of water quality due to excessive biofilm showed after 15 days of operating times.4 excessive biofilm phase, the equivalent biofilm thickness and VSS contents per unit aura were observed in the range of 1,100 to $1,200{\mu}m$ and 2.5 to 3.0mg $VSS/cm^{2}$, respectively. In the aerobic fixed biofilm reactor/anoxic fixed biofilm reactor(AFBR/ANFBR) process with endogenous respiration phase, the BOD removal efficiency was obtained more than 90 percentage at the surface loading rate and volumetric loading rate of the AFBR maintained less than 17 g $BOD/m^{2}{\cdot}$day and 1.7kg $BOD/m^{3}{\cdot}$day, respectively. The removal efficiency of TKN and $NH_{3}$-N at the loading rates below 5.60g $NH_{3}-N/m^{2}{\cdot}day$ and 0.56kg $NH_{3}-N/m^{3}{\cdot}$day were above 76 percentage and 82 percentage, respectively. In order to reduced sludge production rate and aggravation of water quality, endogenous respiration phase was accepted at first AFBR reactor. As a results of this operating condition, sludge production was minimized and removal efficiency was maintained stability.

• BMB Reports
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• 제34권1호
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• pp.21-27
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• 2001

The structural stability of brain pyrydoxine-5'-phosphate (PNP) oxidase and the catalytic properties of the monomeric species were investigated. The unfolding of brain pyridoxine-5'-phosphate (PNP) oxidase by guanidine hydrochloride (GuHCl) was monitored by means of fluorescence and circular dichroism spectroscopy Reversible dissociation of the dimeric enzyme into subunits was attained by the addition of 2 M GuHCl. The perturbation of the secondary structure under the denaturation condition resulted in the release of the cofactor FMN. Separation of the processes of refolding and reassociation of the monomeric species was achieved by the immobilization method. Dimeric PNP oxidase was immobilized by the covalent attachment to Affi-gel 15 without any significant lass of its catalytic activity. Matrix-bound monomeric species were obtained from the reversible refolding processes. The matrix bound-monomer was found to be catalytically active, possessing only a slightly decreased specific activity when compared to the refolded dimeric enzyme. In addition, limited chymotrypsin digestion of the oxidase yields two fragments of 12 and 161 kDa with a concomitant increase of catalytic activity The catalytically active fragment was isolated by ion exchange chromatography and analyzed for association of two subunits using the FPLC gel filtration analysis. The retention time indicated that the catalytic fragment of 16 kDa behaves as a compact monomer. Taken together, these results are consistent with the hypothesis that the native quaternary structure of PNP oxidase is not a prerequisite for catalytic function, but it could play a role in the regulation.