• Maxillofacial Plastic and Reconstructive Surgery
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• 제28권5호
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• pp.454-469
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• 2006

Today, there is considerable evidence to support a cause-effect relationship between microbial colonization and the pathogenesis of implant failures. The presence of bacteria on implant surfaces may result in an inflammation of the peri-implant mucosa, and, if left untreated, it may lead to a progressive destruction of alveolar bone supporting the implant, which has been named as peri-impantitis. Several maintenance regimens and treatment strategies for failing implants have been suggested. Recently, in addition to these conventional tools, the use of different laser systems has also been proposed for treatment of peri-implant infections. As lasers can perform excellent tissue ablation with high bactericidal and detoxification effects, they are expected to be one of the most promising new technical modalities for treatment of failing implants. It is introduced that Er,Cr:YSGG laser, operating at 2780nm, ablates tissue by a hydrokinetic process that prevents temperature rise. We studied the change of the titanium implant surface under scanning electron microscopy after using Er,Cr:YSGG laser at various energies, irradiation time. In this study, Er,Cr:YSGG laser irradiation of implant fixture showed different effects according to implant surface. Er,Cr:YSGG laser in TPS surface with RBM not alter the implant surface under power setting of 4 Watt(W) and irradiation time of 30sec. But in TPS surface with $Ca_3P$ coating alter above power setting of 2W and irradiation time of 10sec. TPS surface with RBM showed microfracture in 4W, 30sec and TPS surface with $Ca_3P$ coating showed destruction of fine crystalline structure, melting in excess of 2W, 10sec. We concluded that proper power setting, air, water of each implant surface must be investigated and implant surface must be irradiated under the damaged extent.

• 한국토양비료학회지
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• 제47권3호
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• pp.187-190
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• 2014

The agricultural policy/Environmental eXtender (APEX) model was developed by the Blackland Research and Extension Center in Temple, Texas. APEX is a flexible and dynamic tool that is capable of simulating a wide array of management practices, cropping systems, and other land uses across a broad range of agricultural landscapes, including whole farms and small watersheds. The model can be configured for novel land management strategies, such as filter strip impacts on pollutant losses from upslope crop fields, vegetated grassed waterways in combination with filter strip impacts, and land application of manure removed from livestock feedlots or waste storage ponds. The APEX model has continually evolved since its inception, and the process of adaptation and modification will likely continue as use of the model expands for an ever-increasing range of environmental problems and conditions. Several improvements to specific model subroutines have already been initiated, while other potential improvements have been identified that will require future research and code modification efforts.

• 한국환경과학회지
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• 제16권3호
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• pp.277-285
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• 2007

The purpose of this study is to analyze seasonal distribution of insects, birds, fishes, and benthos for Gongji stream in Chuncheon and to explore some strategies towards creating a desirable close-to-nature stream. The number of species occurred in the study stream was 23 for butterflies and 149 for other insects, 23 for birds, 15 for fishes, and 47 for benthos. The study stream was dominated by Artogenia rapae, Polygonia caureum, Cyntia cardui for butterflies, and Passer montanus, Anas crecca, Anas platyrhynchos for birds. The dominant species were Rhynchocypris oxycephalus, Zacco plutypus, Carassius auratus for fishes, and Limnodrilus sp. 2, Chiranumus sp. 2, Hydropsyche KUb for benthos. Attracting insect species of higher density requires planting of host plant species and stabilization of plant coverage against disturbances. To enhance species diversify and density of birds, it is desirable to provide diverse habitats including preservation of downstream wetland and natural vegetation, creation of sand bars and islands with sand and gravel, and restriction or traffic passing and parking. Restoring fish and benthos habitats needs improvement of water quality, layout of gravels and stones on sand-dominant streambed, and use of close-to-nature revetment techniques.

• 해양안보
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• 제5권1호
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• pp.113-136
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• 2022

본 논문은 중국의 서해 내해화 전략을 분석하여 해양에 종사하거나, 해양 정책을 연구하는 이들에게 시사점을 제공하기 위해 작성하였다. 이를 위해 최근 서해에서 이루어지고 있는 중국의 해상활동을 아더 라이케가 제시한 전략 구성요소인 목표(Ends), 방법(Ways) 및 수단(Means)의 세 가지 기준으로 분석하였다. 연구 결과, 중국은 서해 내해화라는 목표를 달성하기 위해 국가 차원에서 제 요소를 복합적으로 활용한다는 결과를 도출할 수 있었다. 중국은 ① 정전 상태에 있는 한반도의 특수한 안보 환경을 이용하여 북방한계선(NLL, Northern Limit Line) 인근에서 자국 어선들의 불법조업을 의도적으로 방조하여 서해를 영해로 기정사실화하며, ② 자국의 국가안보에 대한 위협을 이유로 서해상 한･미 연합훈련을 거부하는 한편, 동 해역 내 군사훈련을 확대하고 군용기를 한국방공식별구역 인근으로 상시 진입하게 하여 군사적 능력을 과시하고, ③ 과학탐구를 빙자하여 서해에 각종 시설을 확대 설치하고 있다. 필자가 본 연구를 통해 강조하고 싶은 것은 '서해에서 자행되는 일부 중국의 활동은 한국의 주권을 심각하게 침해하는 행위이며, 한국은 서해에서 국민의 자유로운 해양 활동과 안전을 보장하기 위해 한미 연합전력 중심의 비례적 대응을 해야 한다는 것'이다.

• 대한환경공학회지
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• 제32권7호
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• pp.690-698
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• 2010

유기물에 의한 지하수 자원의 오염이 중요한 환경 문제로 대두되고 있다. 계면활성제 증진 대수층 복원(SEAR)은 유기 오염물에 대하여 가장 유망한 원위치 복원법 중 하나로 인식되고 있다. 계면활성제 또는 계면활성제/폴리머 용액은 복원 프로세스를 촉진시켜 물 세척 시보다 처리 시간을 크게 감소시킨다. 유기물로 오염된 대수층 복원을 위하여 계면활성제 기반의 처리법을 설계할 때 충분한 수치 시뮬레이션을 통한 사전 분석이 매우 중요하다. 본 연구에서는 3차원 다상 다성분 유한 차분 모델인 UTCHEM을 이용하여 유기물 오염 대수층에 대한 SEAR 과정 중 미세에멀젼의 형성과 유동을 분석하였다. 본 연구에서 고려한 복원 프로세스 변수로는 주입 유체의 배열, 유체 주입 및 추출율, 계면활성제 슬러그 및 추격수 내 폴리머 농도, 계면활성제 슬러그 주입 시간 등이다. 각 변수에 대하여 주입 및 생산정에서의 변화와 유기상의 공간적 분포를 비교하였다. 이 결과로부터 정화 시간 및 누적 유기물 회수량을 검토하였다. 본 연구의 결과는 비수상 액체로 오염된 대수층의 정화 시 설계 전략을 수립하는데 중요한 정보를 제공한다.

• 한국환경복원기술학회지
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• 제24권6호
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• pp.1-13
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• 2021

This study was performed to investigate the ecosystem service patterns in relation to climate change acceleration utilizing big data analysis. This study aimed to use big data analysis as one of the network of views to identify convergent thinking in two fields: climate change and ecosystem service. The keywords were analysed to ascertain if there were any differences in the perceiving problems, policy direction, climate change implications, and regional differences. In addition, we examined the research keywords of each continent, the centre of ecosystem service research, and the topics to be referred to in domestic research. The results of the analysis are as follows: First, the keyword centrality of climate change is similar to the detailed indicators of The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) regulations, content, and non-material ecosystem services. Second, the cross-analysis of terms in two journals showed a difference in value-oriented point; the Ecosystem Service Journal identified green infrastructure as having economic value, whereas the Climate Change Journal perceives water, forest, carbon, and biodiversity as management topics. The Climate Change Journal, but not the former, focuses on future predictions. Third, the analysis of the research topics according to continents showed that water and soil are closely related to the economy, and thus, play an important role in policy formulation. This disparity is due to differences in each continent's environmental characteristics, as well as economic and policy issues. This fact can be used to refer to the direction of research on ecosystem services in Korea. Consistent with the recent trend of expanding research regarding the impacts of climate change, it is necessary to study strategies to scientifically predict and respond to the negative effects of climate change.

• 대한영양사협회학술지
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• 제4권2호
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• pp.235-244
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• 1998

Hand washing is an important component of hygiene program for food handlers. Hands can be a source of direct or indirect contamination of foods with pathogenic microorganisms. In this study, the effectiveness of hand washing methods and the use of 70% alcohol solution against transient skin bacteria was tested in an university foodservice facility. 70% alcohol solution is sprayed for 5 seconds automatically when hands are placed in the dispenser. Samples were taken using swab technique in meat cutting area, vegetable trimming area, and vegetable cutting area: before and after washing hands according to planned methods, and after being sprayed with 70% alcohol solution after washing hands. The bacteriological analysis of total plate counts, coliform, fecal coliform of food handlers' hands was done. Statistical data analysis was completed with Mann-Whitney U test and Kruskal-Wallis model using the SPSS program. The levels of initial contamination of workers' hand were significantly different by the work areas($x^2$=9.156, p<0.01). Workers in the vegetable trimming area had more heavily soiled hands than in the other work areas. Mean of TPC counts and coliform was 8.97×$10^5$ CFU/12.4$cm^2$, 2.93×$10^2$ MPN/12.4$cm^2$ respectively, but fecal coliform was not detected. Transient bacteria were removed from hands after washing and using 70% alcohol solution but were not removed completely. Mean reduction percentage in TPC varied among work areas and ranged from 93.19% to 94.99%, and in coliforms from 97.31% to 100%. A significant difference in TPC was found between before and after hand disinfection (Z=-2.714, p<.01) and between standardized hand washing procedures and un-standardized hand washing procedures(z=-2.301, p<.01). Subjects using the hand sanitizer showed a great elimination of TPC(99.45% reduction), but this effect was valid only after following proper washing procedures. Based on the results, the most effective hand washing method was recommended as the combination of the standardized hand washing procedure with warm-water and use of the 70% alcohol solution. The results can be used to develop hand hygiene programs and training strategies for enhancing hand hygiene practices for food handlers in foodservice operations.

• 한국습지학회지
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• 제23권4호
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• pp.327-341
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• 2021

수변생태벨트는 유역의 비점오염원을 저감시키고 생태적인 연결성과 건강성을 증진할 수 있는 효율적인 기법이다. 국내에서도 수변생태벨트 조성 및 관리를 위한 법적인 제도를 운영 중이나 비점오염물질 제어, 생물서식처 등 완충 기능에 유리한 하천, 호소 내의 홍수터는 제외되어 개선이 필요하다. 이에 따라 본 연구에서는 금강 수계 대청댐 유역을 대상으로 댐 호소의 소단위별로 댐 홍수터와 수변구역의 수질, 생태계 특성을 종합적으로 평가하는 통합형 수변생태벨트 적지 선정방안을 제시하고 분석하였다. 먼저 GIS로 대청댐 유역을 138개 소단위로 구분하고 홍수터와 인접한 수변구역을 분석하였다. 통합형 수변생태벨트 적지 선정에 영향을 미치는 생태계, 수질 영향 관련 16개의 평가인자를 선정하고 AHP분석으로 인자별 중요도에 대한 가중치를 설정하였다. 소단위에 제내·외지별, 인자별 가중치를 적용한 통합 평가를 실시하여 적지 우선 순위를 도출하였다. GIS 적지 분석을 통해 도출된 대상지들이 실제 조성에 적합한 지역인지 타당성을 판단하기 위해 5개 대상지에 대한 토지이용, 오염원, 생태적인 연계성 등에 대한 현장 검증을 시행한 결과 모든 대상지가 적정함을 확인할 수 있었다. 본 연구를 통해 제시된 수변생태벨트 적지 분석 기법은 향후 통합적인 수변관리 정책 설정시 유용한 도구로써 적용될 수 있을 것이다. 단, 대상 댐별 특성과 현안에 따라 다양한 평가인자와 항목별 가중치 적용이 필요할 수 있다. 그리고 통합형 수변생태벨트 지역에 대해 그린-블루네트워크(Green-Blue Network) 측면을 고려한 세부적인 보전·복원방안 마련과 생태계서비스 측면의 평가 및 관련 법, 제도 측면의 상호 연계, 개선방안 등에 대해서도 추가적인 연구가 이루어져야 할 것이다.

• 한국환경복원기술학회지
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• 제3권3호
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• pp.45-76
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• 2000

The purposes of this study were to investigate and understand the present status of various types of "deserts", such as sand desert, gravel desert, rock desert, earth desert, salt desert, desert, rocky desert, gobi desert, sandy desert, clay desert, etc., and the general countermeasures for the combating "desertification" "desertization", and to develop the technologies on the revegetation and restoration for the combating desertification in China. The methods of this study were mainly composed of field surveys on the several experimental sites and research institutes related to combating desertification in China, and examinations on the various technologies for the combating desertification at the Daxing Experimental Station of Beijing Forestry University. The conclusion from this study may be summarized as follows; 1. Status and tendency of desertification in China : China is one of the countries seriously threatened by desertification. Desertification affected areas in China are mainly distributed in arid, semi-arid and dry sub-humid areas in China, covering the most regions of the Northeast China (eastern region of Inner-Mongolia), the northern part of the North China (middle and western region of Inner-Mongolia, Shaanxi, Ningsha, Gansu) and the western part of the Northwest China (Xinzang, Qinghai, Xizang). The total area affected by desertification in China is approximately 2.622 million $km^2$. It covers 27.3% of the total territory of China. Until recently, it is estimated that the annual spreading ratio of desertification in China is 2,460 $km^2$. Therefore, desertification is mostly serious problems facing to the Chinese people. 2. The causes and environmental effect of desertification : The desertification in China is mainly caused by compound factors, including natural condition and human activities. In China, the desertification is started by the decrease of precipitation, continuous dry and drought, strong wind, wind and water erosion, land degradation and loss of natural vegetation caused by climate variation, and accelerated by the human activities, such as over-cultivating, over-grazing, over-cutting of woods, irrational use of water resources. Because desertification has affected the geographical features, soil nutrients contents, salinity, vegetation coverage and the functions of ecosystem, the environmental deteriorations in the desertification affected areas are very seriously. 3. The fundamental strategies of combating desertification in China are the increase of education and awareness of people through various mass media, the revision of laws to guarantee operation of Desertification Combating Law and to improve many relating laws and regulations, the application of advanced technologies and training of experts, the establishment of discriminative policies, and increasing arrangement of budget-investment, and so on. China, as a signed country in UNCCD, has made efforts for the combating desertification. Korea is also signed country in UNCCD, so we should play an important role in the desertification combating projects of China for the northest asia and global environmental conservation as well as environmental conservation of Korea.

• Journal of Nutrition and Health
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• 제53권3호
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• pp.255-270
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• 2020

본 연구는 2019년 제15차 청소년건강행태온라인조사 원시자료를 활용하여 청소년들의 편의 식품 섭취 경험에 영향을 미치는 요인을 인구사회학적 특성, 정신건강 특성, 그리고 건강행태 특성으로 구분하여 살펴보았다. 연구 결과에 의하면 청소년들의 편의식품 섭취에 영향을 미치는 요인으로 인구사회학적 특성인 성별, 주관적 학업성적, 주관적 경제상태뿐만 아니라 정신건강 요인인 스트레스 인지, 주관적 수면 충족, 우울감 경험, 자살 생각이 유의한 변수로 확인되었으며, 건강행태 요인으로 아침식사 결식, 패스트푸드, 단 음료 섭취 등과 같은 식생활 행태뿐만 아니라 흡연, 음주, 약물복용 등의 요인도 청소년들의 편의식품 섭취에 영향을 미치는 것으로 확인되었다. 이러한 결과를 바탕으로 청소년들의 편의식품 섭취를 줄이기 위해서는 가정에서는 청소년들이 아침식사, 채소, 과일, 우유 섭취와 같은 건강한 식습관 및 충분한 수면 습관을 형성하도록 돕는 자녀교육이 필요하며, 학교에서는 청소년들이 건강한 식품을 선택하고 손쉬운 건강식을 스스로 만들어 먹을 수 있는 기술을 습득하도록 돕는 영양교육이 필요하다. 특히 편의식품 섭취 빈도가 높은 청소년들을 대상으로 스트레스를 관리하고 금연, 금주와 같은 건강증진 행위를 실천하도록 돕는 건강교육이 함께 실시될 필요가 있다. 정부에서는 청소년들에게 건강한 식품을 제공할 수 있는 소매 업체가 우선적으로 학교 주변에 위치할 수 있도록 법률을 제정하거나, 학교 주변 소매 환경에서 양질의 편의식품이 판매될 방안을 마련할 필요가 있다. 이러한 결과를 바탕으로 향후에는 청소년의 편의식품 섭취에 영향을 미치는 요인을 종단적으로 연구할 것을 제언한다.