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        검색결과 485

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In addition to its effectiveness in resolving apical periodontitis, regenerative endodontic treatment (RET) has advantages of inducing root maturation and restoring innate immunity or sensory function through revascularization. However, its adoption in mature teeth in adults has been scarce due to limited stem cell sources and constricted apical size. In recent years, there have been instances of studies performing RET in mature permanent teeth. The present case report describes the treatment of apical periodontitis in a previously treated mature permanent tooth using RET with a 3-year follow up. In the present case, a 34-year-old female patient presented with previously treated maxillary lateral incisor with a large radiolucency. After removal of previous gutta percha within the root canal, bleeding was induced by passing hand file beyond root apex and calcium hydroxide was applied over the blood clot. During the 9-month follow-up, a reduction in periapical radiolucency was observed. Subsequently, after removing calcium hydroxide, apical bleeding was induced again and mineral trioxide silicate was placed up to 3mm beneath cemento-enamel junction, above the blood clot. The tooth was later restored with glass-ionomer cement and composite resin. After 3 years, the tooth was asymptomatic and radiographic evaluations showed complete resolution of periapical radiolucency with presence of normal lamina dura and periodontal ligament space. In conclusion, modified RET with long-term calcium hydroxide application is a potentially viable treatment option for previously treated mature permanent teeth with apical periodontitis. However, further clinical studies with larger number of cases are recommended to verify its effect.
        4,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Safety Evaluation of Wind Loads of Renewable Energy and Photovoltaic Power Structures. METHODS : Structural safety evaluation was conducted on the wind load of 3kW Photovoltaic Power Structures using ABAQUS. Wind speed was reviewed for 36m/s and 60m/s. Effective Mass and Mass Contribution of Photovoltaic Power Structures was utilized up to 90%. 7 steps were set and applied to structural analysis. RESULTS : As a result of the structural analysis, it was confirmed that the long-term blowing load was affected rather than the size of the wind load. Weak areas were identified at the point of the horizontal beam rather than the modules of the Photovoltaic Power Structures. In particular, it was confirmed that stress exceeding the allowable stress was generated at the junction. In order to secure the safety of Photovoltaic Power Structures, it is judged that reinforcement of the branch is necessary. CONCLUSIONS : The safety of Photovoltaic Power Structures structures for wind load is influenced by persistence rather than the size of the wind load. Therefore, in order to prevent this, it is judged that reinforcement of the branch is necessary.
        4,000원
        6.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        조던 감독은 아일랜드를 배경으로 정치적, 젠더적, 성적 갈등과 서사가 풍부한 『크라잉 게임』을 통해 구성원들의 가치관과 철학을 체계적으로 정리한 새로운 신화를 제시하고 있다. 이 논문에서는 이 작품에서 제시되는 신화의 강제성과 함께 사실적으로는 새로운 신화가 아니라 보수적이며 남성 중심의 폭력적이며 강제적인 신화를 재생할 뿐이라는 것을 보여준다.
        4,500원
        7.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The process of extracting and recovering an asphalt binder from an asphalt mixture is harmful to the human body and can affect the properties of the asphalt binder owing to the presence of residual solvent quantities. This study was conducted to determine the properties of aged asphalt binders based on rejuvenator content without extracting and recovering the asphalt binders using RAP mortar. METHODS : After extracting and recovering aged binders from waste asphalt, a rejuvenator was added at a certain rate to evaluate the physical and rheological properties of the binder based on the added amount. RESULTS : When the rejuvenator content was greater than necessary, the absolute viscosity was not properly measured owing to the behavior of the rejuvenator. The phase angle was measured to be almost 90°, thus indicating that it acted as a liquid . In addition, the shear strain and nonrecovery compliance also increased significantly. CONCLUSIONS : If an excess rejuvenator quantity was added to the aged binder, the absolute viscosity was not properly measured, the phase angle was measured to be almost 90°, and the shear strain increased significantly. It is also necessary to conduct the same tests on different types of RAPs to ensure that the results of this study are reasonable.
        4,000원
        9.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 PET를 재활용하여 만든 물질재생 PET사를 함침공정을 통해 고전도성의 E-textile로 제작하는 것이다. 소수성의 성질을 가지고 있는 PET사는 virgin과 recycled 모두 함침공정을 통해 전자섬유로 제작되었을 때에 높은 전도성을 부여하기 힘들다는 특징이 있다. 함침공정의 효율성 향상을 위해 FEMTO SCIENCE사의 Covance-2mprfq 모델을 사용하여 재생 PET사로 이루어진 시료를 50w 5분, 10분간 플라즈마로 표면 개질하였다. 이 후 SWCNT 분산액(.1wt%, cobon 사)에 5분간 시료를 담근 후 패딩기(Padder, DAELIM lab)를 통해 시료 안쪽으로 용액이 잘 스며들도록 Dip-coating 진행하였다. 공정이 완료된 후 저항측정을 양끝점에서 멀티미터를 통해 측정하 고 좀 더 넓은 전극을 통해 정밀하게 다시 측정하였다. 고찰한 결과 플라즈마 표면 개질을 통해 함침공정을 통한 고전도성 부여가 가능해졌음을 확인할 수 있었다. 10분간 표면 개질한 경우 저항이 최대 2.880배 감소하였다. 본 연구결과를 기반으로 스마트 웨어러블 분야에서 활용되는 E-textile 또한 recycle 소재로 제작함으로써 석유자원을 절약하고 탄소배출량을 감소시킬 수 있는 스마트 웨어러블 제품을 개발하고자 한다.
        4,000원
        10.
        2023.03 구독 인증기관 무료, 개인회원 유료
        홀로그램 이미지를 표시할 수 있는 자동차 리어 램프를 제작했다. 홀로그램은 노광할 때 물체 광은 0도, 참조 광은 60도가 되게 광학계를 설계해 투과 타입으로 제작했다. 홀로그램과 광원을 일체형으로 하면서 두께 30mm의 콤팩트 한 재생 장치를 제작했다. 홀로그램 크기는 200×100mm로 제작했다. 에지릿 홀로그램으로 콤팩트 한 재생 장치에 적 용하기 적합했다. 리어 램프는 미등, 정지등, 방향지시등, 후진등과 홀로그램 재생 장치를 포함 시켜 아크릴로 제작했 다. 리어 램프의 외관은 홀로그램 이미지의 의도와 연결되게 배트맨 모양으로 디자인했다. 에지릿 홀로그램을 이용한 콤팩트 한 재생 장치는 리어 램프의 기능과 연계해 사용하기에 적합하다는 것을 확인하였다.
        4,000원
        11.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 지방도시재생 리빙랩을 위한 종합적이고 체계적인 평가지표를 마련하는 것이다. 특히 이 연구는 지방소멸의 전형적인 사례인 전주 물왕멀을 중심으로 이루어졌다. 전주의 도시재생 리빙랩인 물왕멀공동체의 이해관계자들을 대상으로 조사를 실시한 결과, 여러 평가 지표 중 특히 민주성에서도 주민의 참여비중과 주민 누구나 참여가능한지의 여부를 매우 중요하게 인식했다. 이는 향후 사업책임자의 선정 시 중요하게 평가되고 고려되어야 할 지표를 시사해 준다. 종합하면, 지방도시재생 리빙랩의 성패는 주요 이해관계자인 주민의 참여에 달려있다. 특히 노령인구의 비율이 높은 지방 축소도시의 특성상, 고령자의 눈높이에 적합한 사업을 선정하고 집행하는 한편 높은 전문성을 가진 사업책임자를 배치하여 진입장벽을 낮추는 데 세심하게 주의를 기울임으로써 주민의 참여욕구를 충족하는 것이 중요하다.
        4,000원
        12.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        As the environmental impacts of fossil fuel energy sources increase, the South Korean government has tried to change non-environmental- friendly enery sources to environmental-friendly energy sources in order to mitigate environmental effects, which lead to global warming and air pollution. With both a limited budget and limited time, it is essential to accurately evaluate the economic and environmental effects of renewable energy projects for the efficient and effective operation of renewable energy plants. Although the traditional economic evaluation methods are not ideal for evaluating the economic impacts of renewable energy projects, they can still be used for this purpose. Renewable energy projects involve many risks due to various uncertainties. For this reason, this study utilizes a real option method, the Geske compound model, to evaluate the renewable energy projects on Jeju Island in terms of economic and environmental values. This study has developed an economic evaluation model based on the Geske compound model to investigate the influences of flexibility and uncertainty factors on the evaluation process. This study further conducts a sensitivity analysis to examine how two uncertainty factors (namely, investment cost and wind energy production) influence the economic and environmental value of renewable energy projects.
        4,200원
        16.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        바이오산업의 발전으로 의약품, 식품 등의 생산 과정의 분리/정제 공정에 사용되어 왔던 기존의 컬럼 크로마토그 래피를 대체하여 더 높은 처리효율을 갖는 막 크로마토그래피가 부상하고 있다. 본 연구에서는 서로 다른 기공 크기의 두 가 지 상용 셀룰로오스 아세테이트(Cellulose acetate, CA) 분리막을 탈아세틸화 과정을 통해, 리간드의 개질이 용이한 다공성 재 생 셀룰로오스 지지체를(Regenerated cellulose, RC) 제조하였다. 음이온 교환능을 부여하고자 grafting을 수행하였으며, 구체 적으로는 UV 중합법을 통해 4차 암모늄을 포함하는 음이온 교환 리간드(MAPTAC)를 부착하여 음이온 교환용 흡착막을 제 조하였다. 단백질 흡착 용량은 정적 흡착 용량(Static binding capacity, SBC)시험을 통해 총 단백질 흡착 용량을 측정했고, 동 적 흡착 용량(Dynamic binding capacity, DBC)을 측정하여 상용막과 비교 평가하였다. 성능 평가 결과 단백질 흡착량은 넓은 표면적에 의해 리간드 밀도가 높은, 기공 크기가 작은 순서로 높게 측정되었고, 상용 CA분리막을 탈아세틸화하고 리간드를 부착시킨 분리막(RC 0.8 + MAPTAC 43.69 mg/ml, RC 3.0 + MAPTAC 36.33 mg/ml)이 상용 막 크로마토그래피 제품(28.38 mg/ml) 대비 높은 흡착 용량을 보였다.
        4,000원
        17.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        While protecting its lives and property from natural disasters such as floods and droughts, North Korea needs to develop into an informationized industrial society by securing renewable energy power in the era of energy transition. In addition, existing research has considered that a policy of continuous and consistent expansion of renewable energy based on the safety of the lives of ordinary people could be the solution. South Korea needs to recognize that the supply of energy for a minimum of living is more important to the North Korean people than the economic benefits of securing North Korea's renewable energy market. Therefore, in this paper, from that point of view, we have calculated the amount of electricity that North Korea lacks necessary for the lives of its inhabitants that can be replaced by renewable energy, and considered ways to estimate the market value.
        4,000원
        20.
        2022.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Preventive pavement maintenance is an economical and efficient method of infrastructure management. This study aims to improve the performance of cold thin-layer asphalt pavement, which is mainly used in earthwork pavement, and for bridge overlays and structures. METHODS : A cold asphalt mixture of modified emulsified asphalt and RAP was prepared for cold recycled thin-layer asphalt pavement. The performance of the mixture as a function of fiber reinforcement to improve flexural strength and crack resistance was evaluated. RESULTS : The use of RAP aggregate in cold asphalt mixture was found to increase the cohesive strength of the mixture and improve the wet abrasion resistance due to the effect of the residual binder. As a result of the loaded wheel test and flexural tension test with the addition of fiber reinforcement, it was found that the crack resistance of 0.4 % glass fiber was the best, and especially, the flexibility at low temperature was excellent. CONCLUSIONS : The cold recycled thin-layer asphalt pavement mixture has improved cohesive strength, flexural strength, and crack resistance compared to existing cold asphalt pavement materials, so it will contribute to economical and effective maintenance in preventive maintenance of bridge overlays and structural pavements.
        4,000원
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