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        검색결과 11

        1.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, it has been applied and used in various fields using 3D printing. Since it is closely connected to our lives, the mechanical properties of the output are actively studied. Therefore, in this study, tensile specimens were manufactured using the FDM lamination method using PLA materials, and the changes in tensile properties were compared and evaluated. First, 120 tensile specimens were manufactured using the spacing angle and lamination density of the lamination angle as control factors. After that, a tensile test was conducted at the same tensile speed of 5mm/s to compare and evaluate the tensile strength and elastic modulus. As a result, it was found that the tensile strength and elastic modulus increased linearly with density than the lamination angle. In addition, when the laminating angle was 0°, the tensile strength and elastic modulus were the largest. When the laminating angle was 108°, the lowest tensile strength and elastic modulus were confirmed.
        4,000원
        2.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we evaluated the filtering effect of the fine dust mask. Our objective research has secured credibility in the private sector. The performance of domestic fine dust masks is evaluated by three dust collection efficiencies, inspiratory resistance, and leakage rate according to KF grade in the health mask standard guidelines issued by the Ministry of Food and Drug Safety. Based on this, eight types of fine dust masks were evaluated for dust collection efficiency and face intake resistance. All masks showed good performance as the collection efficiency was 90%. The higher the KF grade, the higher the collection efficiency, but the inspiratory resistance had no correlation with the grade. According to the manufacturer's operation method, masks below the standard value may be distributed. Masks that are currently on the market have shown results that can be trusted. However, we hope that the system will be improved to validate whether the masks that meet the threshold are still being distributed.
        4,000원
        3.
        2015.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effects of the mixing of an active material and a conductive additive on the electrochemical performance of an electric double layer capacitor (EDLC) electrode were investigated. Coin-type EDLC cells with an organic electrolyte were fabricated using the electrode samples with different ball-milling times for the mixing of an active material and a conductive additive. The ball-milling time had a strong influence on the electrochemical performance of the EDLC electrode. The homogeneous mixing of the active material and the conductive additive by ball-milling was very important to obtain an efficient EDLC electrode. However, an EDLC electrode with an excessive ball-milling time displayed low electrical conductivity due to the characteristic change of a conductive additive, leading to poor electrochemical performance. The mixing of an active material and a conductive additive played a crucial role in determining the electrochemical performance of EDLC electrode. The optimal ball-milling time contributed to a homogeneous mixing of an active material and a conductive additive, leading to good electrochemical performance of the EDLC electrode.
        4,000원
        4.
        2013.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        돼지의 육질과 관련하여 지방침착의 중요도가 높아짐에 따라 지방대사 또는 지방축적과 관련한 후보유전자 발굴 을 위해 등지방 조직 유래의 cDNA microarray를 이용하여 품종별 지방함량관련 조직의 유전자 발현 양상을 분석하 였다. 그 결과 재래돼지의 등지방 조직에서 SCD (stearoyl-CoA desaturase)와 ELOVL6 (elongation of very long chain fatty acid 6)가 높은 발현을 보였고, 간에서 FMO1 (hepatic flavin-containing mono oxygenase)이 높은 발현을 보였으며, 요크셔는 간에서 FGG (fibrinogen gamma polypeptide)와 C3d (com- plement component c3d), 등지방에서 COL3A1 (type Ⅲ collagen alpha 1)이 높은 발현을 보이는 것을 확인하였다. Real-time PCR을 통해 microarray data의 validation과 품종간 유전자 발현량을 비교하여, 위의 유전자들 중 지방함량에 따른 차등발현 유전자로 SCD, ELOVL6 그리고 FGG를 선정하였다. 선정된 유전자 SCD, ELOVL6, FGG는 지방대사에 관여하며 근내지방 함량에도 영향을 미쳐 향후 육질개선에 유용한 후보유전자로 서 활용가능성을 제시하였다.
        4,300원
        5.
        2005.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The balanced scorecard(B SC) overcomes the limit of traditional financial statement that focuses on only financial performance. BSC is widely used in government and industry because of the clear representation of the relationship and logic between the key
        4,000원
        6.
        2018.05 서비스 종료(열람 제한)
        호소의 부영양화와 같은 수계오염을 유발하는 질소 및 인에 대한 방류수 수질기준 규제가 점차 강화되고 있으며, 최종 개정된 방류수 수질기준에서는 처리수를 Ⅰ지역에 방류하는 경우, 총 질소 20 mg-N/L, 총 인 0.2 mg-P/L로 규제하고 있다. 이에 따라 대부분의 공공하수처리시설은 고도처리공법을 확보하고 있으며 현재 운영중인 고도처리시설에는 생물학적 고도처리법인 SBR공법과 A O 공법이 가장 많이 적용되고 있다. 그러나 한국 하수 성상의 경우 질소에 대한 유기물의 비율이 낮기 때문에 질소 제거효율이 낮고, 탈질을 위해 외부 탄소원을 추가적으로 주입함에 따라 운영비의 증가 문제가 발생된다. 외부 탄소원의 주입에도 불구하고 2015년 환경부에서 발표한 방류수 수질현황을 참고하면 공공하수처리시설의 T-N 제거효율은 약 70%에 그친다. 이에 본 연구에서는 국내 생물학적 고도처리법으로 가장 많이 적용되고 있는 SBR 공법에 수처리용 스펀지 담체를 투입하였을 때, 폭기구간에서의 질소제거 효율을 평가하고자 하였다. 스펀지 담체와 같이 담체 내외부의 물질전달이 자유로운 담체의 경우, 담체 내외부에 형성되는 산소 농도구배로 인하여 담체 내부에는 국소적인 무산소 조건이 형성되며, 그에 따라 담체 외부에서는 질산화가 내부에서는 탈질이 일어나는 SND(Simultaneous Nitrification and Denitrification) 기작이 일어날 수 있다. 이에 폭기 전・후의 암모니아성 질소와 질산성 질소 측정을 통해 SND 효율을 계산한 결과, 약 30%의 효율을 나타내었으며, 이는 탈질이 유도되는 단위공정에서 탈질에 필요한 외부탄소원의 요구량을 감축시킬 수 있으므로 경제적인 측면에서 긍정적인 영향을 미칠 것으로 사료된다.
        7.
        2011.06 KCI 등재 서비스 종료(열람 제한)
        This study investigates the users’perception of the importance and performance of National Recreation Forest Service Programs quality, forest environmental education and cultural benefits, with the aim of improving the level of service quality within the programs. An Important-Performance Analysis (IPA) was performed to determine significant patterns. The IPA results showed that most users’perceived as important how well the service programs performed to meet their expectations. The enclosed study finds, for example, users’answered that three factors which were less important to them were entrance fee, size of program center or facilities and amount of information. These factors performed poorly, and the program of guidance indicates the need for improvement of these factors. In addition, the finding also suggests how recreational service programs in the future can complement and improve what they offer. These are as follows. The process of preparation and content of the program order need to be effectively established. The Program Director needs to maintain a friendly attitude and must have ongoing training on how to provide effective programs. For programs to be enjoyable and satisfying for users, the location of the programs should provide a comfortable environment. Also, detailed program guidance is required for users’ convenience. It is expected that the results of this study will be useful when ameliorating and establishing the marketing strategy of the National Recreation Forest Service Programs.
        8.
        2009.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to examine the relations between using experience of environmental education facilities and attitude toward environmental education in parents who have elementary students in Seattle, U.S. The findings of this study represented that elementary parents have a great understanding about the importance of environmental education. Parents have a strong agreement with the necessity of environmental education in childhood. This research also found the differences between grades and facilities for environmental education in expected effect on environmental education and desirable fields of environmental education. The awareness of the importance of environmental education increased according to frequency in using environmental education facilities. In addition, the more the experiences of using various environmental education facilities, such as museum of natural history, science museum, arboretum, and aquarium expanded, the more educational effects positively increased over time.
        9.
        2005.12 KCI 등재 서비스 종료(열람 제한)
        This study is carried out for obtaining the basic materials for presentation of creation and desirable management of urban roadside trees through analyse the existence effect of trees on people who operate th commercial areas along the streets. Roadside tree and green areas are recognized comfort space in addition to simple planting area. Therefore various trees and flowering plants should be introduced in addition to roadside facilities for convenience. Planted roadside trees should be maintained. We will propose an method that residents plant and manage the trees and flowering plants on the two lane of one way road. However main lines more than four lane of one way have more public property beside the residents space. Therefore these should be maintained mainly by related government agencies.
        10.
        2005.03 KCI 등재 서비스 종료(열람 제한)
        This study analyzes the recognition of commercial business men and employers who operate the commercial zone along the streets in the downtown area on the planting for the roadside green space forming the important frame of greening in the downtown among the open spaces. Through the analysis, this study attempts to get the basic data to suggest the recommendable directions in planting and managing the street trees in the downtown. The results of this study are summarized as described below. The street green spaces are very important in improving the environment of the downtown and their necessities are also very critical. It was found that the street trees were recognized as the critical factor to enhance the aesthetical values of the city, provide the green shades and purify the air. This study also identified that the street trees have the positive impacts on the business environment rather than negative impacts. In maintaining the street green spaces, the most necessity is the service facility such as resting areas, toilets and garbage bins with the street trees. The commercial business men and employers who operate the businesses along the streets preferred the double layer type that the tall trees and green walls are planted together along the streets for the street planting. For securing the green shades in the city, the planting of linear green spaces such as streets and waterways is critical. Moreover, the street trees accounts for the important position in the urban open spaces. The majority of commercial business men and employers consider the participation of citizens for greening as the very essential factor.
        11.
        2003.02 KCI 등재 서비스 종료(열람 제한)
        This study was carried out to present rural functional resources through classification and preparation of checklist for ecological and cultural resources which considered various aspect of agriculture and rural area. In this study the function of ecological and cultural resources classified 6 functions such as natural environment, free environmentally agricultural products, experience of agricultural products, recreational places, rural life experience, and Interchanges of human resources. Prepared evaluation list through this study can explain a local characteristics based on 6 functions of agricultural and mountain village. This evaluation list was focused on the magnitude of the resources which motivate the visiting of city-dweller as a consumer, for an actual regional plan, investigation of the inhabitant consciousness survey should be needed, simultaneously.