• 한국콘텐츠학회논문지
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• 제10권7호
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• pp.317-325
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• 2010

이 연구는 PPA 기법을 적용하여 민간경호경비원들의 여가활동 집중개선 여가활동을 도출하고, 나아가 여가제약이 참가지수에 미치는 영향을 규명하는데 주된 목적이 있다. 이러한 과정을 통하여 최종적으로 민간경호경비원들의 여가후생복지 개선을 위한 정책투자우선순위를 도출하고자 한다. 따라서 본 연구는 2010년 2월 서울 소재 6개소 민간경비업체를 대상으로 판단표집법을 적용하여 최종분석에 사용된 사례 수는 총 267명이다. 수집된 자료는 SPSSWIN 17.0 프로그램으로 요인분석, 신뢰도 분석, 대응표본 t검증, PPA 분석, 회귀분석을 실시하였다. 설문지의 신뢰도는 Cronbach's $\alpha$값이 .768 이상으로 나타났다. 결론은 다음과 같다. 첫째, 민간경호경비원의 여가활동 참가 지수인 선호도와 참여도는 차이가 있다. 중점개선 여가활동은 헬스, 산책/조깅, 숙박관광, 당일여행 등이며, 노력지속 여가활동은 영화, 국내유명관광지, 이성교재, 외식, 대인관계, 스포츠 관람, 독서, 노래방, TV 비디오 시청, 음주 등이다. 개선요망 여가활동은 수상스포츠, 등산, 자전거, 축구, 사진촬영, 구기운동, 항공스포츠, 바둑/장기, 인라인스케이트, 요리 등이다. 둘째, 민간경호경비원의 여가제약은 여가활동 참가지수에 영향을 미친다. 여가제약의 하위요인인 개인내적 제약, 주변의식적 제약이 클수록 선호하는 여가활동 참가지수는 감소하는 반면, 구조적 제약, 시간 경제적 제약과 같은 어려움을 극복할 경우 여가활동 참가지수는 증가한다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.11-15
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• 1997

We used the photoreactive poly(allylamie) (PPA) as the hydrophilic membrane to control the release of drug from polyurethane(PU). PPA was covalently bonded onto PU surface through the highly reactive nitrene intermediate upon UV light irradiation $(3.3mW/cm^2)$ at 254nm for 5min. Thus the release rate of rifampicin from PU surface was controlled. To know the characteristics of PU surface bonded with PPA, we measured the ATR-FTIR, ESCA, Static Contact Angle and SEM. From these, we suggest that PPA as a hydrophilic membrane is enable to control the release rate of a hydrophobic drug from polymer without the change of bulk property.

• 대한의용생체공학회:의공학회지
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• 제20권6호
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• pp.547-553
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• 1999

생체재료로 사용되는 polyurethane(PU) 표면에 항혈전성 lumbrokinase(LK)를 고정함으로써 생체적합성을 향상시키고자하였다. 먼저 LK를 PU 표면에 고정하기 위한 가교제로서 4-azidoaniline hydrochloride와 poly(acrylic acid)를 이용하여 4-azidophenyl 작용기가 amido 결합으로 치환된 수용성, 광반응성 poly(acrylic acid)(PPa-II)를 합성하였다. H-nuclear magnetic reasonance spectrum(500MHz H-NMR)의 6-7 peak와 infrared spectrum (FT-IR) 의 2125.48 cm peak으로부터 PPA-II의 합성을 지원하였다. EH한 4-azidophenyl 작용기가 poly(acrylid acid) 잔기에 치환된 정도는 UV/VIS adpectrophotometric spectrum을 확인한 결과 11~14%임을 알 수있었다. 0.5 1및 5% PPA-II를 각각 광반응하여 얻은 PU는 39.5, 161.8 및 181.5 nmole/$\textrm{cm}^2$의 농도로 표면에 carvoxyl 작용기가 유도되었음을 알 수있었다. 0.05M KH2PO4 (pH 4.5) 용액에서 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide(EDC)를 촉매로 사용하여 LK를 PU표면에 amido 공유결합으로 고정하였으며, 이것은 지속적인 fibrinolytic 활성도를 보였다. PPA-II를 이용한 표면 개질 방법은 수용성 반응조건에서 이루어진다는 점과 광반응을 이용함으로써 특정부위에서의 표면개질이 가능하다는 점에서 그 응용가치가 크며 아울러 PU의 생체적합성을 향상시킬 수 있는 방법으로서 판단된다.

• Current Photovoltaic Research
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• 제10권2호
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• pp.62-71
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• 2022

The Global RE100 campaign is a one of the voluntary campaign, but it has a lot of influence on domestic companies that have not yet joined the Global RE100. Accordingly, the Korean government introduced the Korean RE100 (K-RE100) system to prepare an institutional mechanism for domestic companies to respond to RE100. However, in Korea, due to the high LCOE of renewable energy and institutional limitations of the power transaction system, there is a limit for companies to implement RE100 in various ways. Therefore, in this study, the implementation cost of RE100 for green tariff, REC purchase, third-party PPA, direct(or corporate) PPA, and self-generation was compared and analyzed to derive the order of implementation with the net present value (NPV) of costs incurred over 20 years. As a result, self-construction was analyzed as the most economical method, but the implementation through the green tariff seemed to be the most realistic implementation method so far. However, considering the gradually falling LCOE, third-party PPA and direct PPA could be secured competitiveness against green tariff in 2025 and 2026. Then it could allow the companies to have various portfolios for implementation of RE100.

• Imaging Science in Dentistry
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• 제49권4호
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• pp.265-272
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• 2019

Purpose: To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) with that of parallel(PPA) and oblique projected periapical(OPA) radiography for the detection of different types of peri-implant bone defects. Materials and Methods: Forty implants inserted into bovine rib blocks were used. Thirty had standardized bone defects(10 each of angular, fenestration, and dehiscence defects), and 10 were defect-free controls. CBCT, PPA, and OPA images of the samples were acquired. The images were evaluated twice by each of 2 blinded observers regarding the presence or absence and the type of the defects. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were determined for each radiographic technique. The 3 modalities were compared using the Fisher exact and chi-square tests, with P<0.05 considered as statistical significance. Results: High inter-examiner reliability was observed for the 3 techniques. Angular defects were detected with high sensitivity and specificity by all 3 modalities. CBCT and OPA showed similar AUC and sensitivity in the detection of fenestration defects. In the identification of dehiscence defects, CBCT showed the highest sensitivity, followed by OPA and PPA, respectively. CBCT and OPA had a significantly greater ability than PPA to detect fenestration and dehiscence defects(P<0.05). Conclusion: The application of OPA radiography in addition to routine PPA imaging as a radiographic follow-up method for dental implantation greatly enhances the visualization of fenestration and dehiscence defects. CBCT properly depicted all defect types studied, but it involves a relatively high dose of radiation and cost.

• Journal of Applied Biological Chemistry
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• 제53권3호
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• pp.162-169
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• 2010

도화 추출물의 항산화능 및 항염증 효과를 검증하여 기능성 화장품 소재로서의 가능성을 검증하였다. 도화의 항산화능 측정으로 전자공여능을 측정한 결과 도화 에탄올 및 아세톤 추출물 500ppm에서 90.0% 이상의 효과를 나타내어, 합성 항산화제로 알려진 BHT와 유사한 효과를 나타내었으며, SOD 유사활성능 측정 결과 도화 에탄올 및 아세톤 추출물 1,000ppm에서 40.0% 이상의 활성을 나타내었다. Xanthine oxidase 저해활성능 측정 결과 도화 에탄올 및 아세톤 추출물 1,000 ppm에서 vitamin C와 유사한 30.0%의 효과를 나타내어, 도화 열수 추출물에 비해 도화 에탄올 및 아세톤 추출물의 효과가 높게 나타났다. 항염증 효과 측정으로 hyaluronidase 저해활성을 측정한 결과 도화 열수, 에탄올 및 아세톤 추출물에서 35.0%의 저해활성을 나타내었으며, macrophage 세포를 이용한 nitric oxide (NO) 저해활성을 측정한 결과 도화 추출물 모든 농도에서 12시간 이후부터 NO 생성량이 억제됨을 확인할 수 있었다. 또한 피부염증 유발균인 Staphylococcus epidermidis와 Propionibacterium acnes의 항균효과를 측정한 결과 도화 에탄올 추출물에서 항균 효과를 나타내었다.

• 한국의류산업학회지
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• 제20권5호
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• pp.600-607
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• 2018

Polypropylene fibers, while having many advantages such as light weight, sweat fast drying, water-repellent, drainage, thermal insulation, anti-static property has a drawback in dyeing. In recent years, the development of dyeable polypropylene fibers has expanded its value in the textile market. The purpose of this study is to fabricate composite spun yarns using polypropylene, acrylic, rayon and wool and to analyze tensile properties, uniformity characteristics, bending properties, hairiness, and surface shape according to the degree of fineness and blended ratio. The specimens consisted of 100% polypropylene spun yarn pp30, pp40 and ppa(pp/acrylic), ppr(pp/rayon), ppw(pp/wool), 5 altogether sed in this study. The results of the study are as follows. The breaking strength of polypropylene spun yarn blended with rayon and acrylic was higher than that of 100% polypropylene spun yarn. The polypropylene spun yarn is higher the fineness been shown to decrease the breaking strength and elongation. The bending properties of polypropylene spun yarns were in the order of ppa>ppr>pp40>pp30>ppw. The unevenness of ppw, ppr, and ppa was higher than pp40 and pp30. With the exception of ppw with crimp properties, pp30 and pp40 were found to have a hairiness index greater than ppr, ppa. In the microscopic photographs of polypropylene spun yarn, pp30, which had the highest hairiness index, was found to have a thick yarn and a large number of hairs, and ppw had hairs of 3 mm or more protruding elongated outwardly.

• 신재생에너지
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• 제18권3호
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• pp.43-59
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• 2022

The green premium is the most important feature of Korea's RE100 system. Green premium has three characteristics. The first, the cost of implementation is lower than that of other means of implementation. The second, it is linked with the RPS system to keep the means of implementing the green premium low. Third, the funds raised by the green premium are used to supply renewable energy to compensate for the additionality that the green premium does not have. When the entire industrial sector's electricity consumption is converted to renewable energy, the implementation cost of the green premium is estimated to be 3,377.4 billion won, and the REC purchase is estimated to incur the implementation cost of 6,576.4 billion won, which is 3.5 trillion more than the green premium. It was analyzed that an additional implementation cost of KRW 100 million would occur. In addition, in the case of solar PPA, it was analyzed that additional implementation costs of KRW 13,375.7 billion to KRW 16,162.3 billion were incurred. It was estimated that the renewable energy that could be supplied to the green premium would at least be sufficient for companies exporting to the US and EU. In addition, it was analyzed that when the fund created as a green premium is used for renewable energy supply, about 30.7% of the renewable energy supply through PPA can be supplied. However, as ESG is emphasized, green premium can be criticized by green washing because there is no additionality. There is also a limit to responding to the EU's CBAM. Therefore, companies can use the green premium depending on the situation, but it is more advantageous to use PPA, etc. The government needs to sufficiently maintain the supply of renewable energy using the fund to maintain the green premium.

• 한국응용과학기술학회지
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• 제24권3호
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• pp.287-295
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• 2007

Three phosphorus functional groups were introduced in one structural unit of polymer backbone to enhance the flame retardancy of PU coatings. In the first step, we synthesized tetramethylene bis(orthophosphate) (TBOP) that contained two phosphorus functional groups in one structural unit. In the next step, we synthesized modified polyesters (ATBTP-10C, -20C, -30C) that contained triphosphorus group using TBOP, 1,4-butanediol, trimethylolpropane, adipic acid, and another functional monomer, phenylphosphonic acid (PPA). The amount of PPA in ATBTPs was adjusted from 10 wt% to 30 wt%. The structure and characteristics of ATBTPs were examined using FT-IR, NMR, GPC, and TGA analysis. From the thermo-behavior test of diphosphorus modified polyester (ATBT) and ATBTPs, the afterglow of ATBT, ATBTP-10C, ATBTP-20C, and ATBTP-30C were 24.7, 27.1, 29.0, and 31.7%, respectively. It was found from this result that the afterglow increased with the amount of PPA component.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.656-658
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• 2011

A green and efficient method for the synthesis of 3,4-dihydropyrimidin-2(1H)-ones and -thiones through one-pot three-component reaction of ethyl acetoacetate, an aryl aldehyde, and urea or thiourea in acetonitrile using silica gel-supported polyphosphoric acid (PPA-$SiO_2$) as catalyst is described. Compared to the classical Biginelli reaction conditions, the present methodology offers several advantages such as high yields, relatively short reaction times, mild reaction condition and a recyclable catalyst with a very easy work up.