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        검색결과 19

        1.
        2022.05 구독 인증기관·개인회원 무료
        The International Atomic Energy Agency recommends the deep geological disposal system as one of the disposal methods for high-level radioactive waste (HLW), such as spent nuclear fuel. The deep geological disposal system disposes of HLW in a deep and stable geological formation to isolate the HLW from the human biosphere and restrict the inflow of radionuclides into the ecosystem. It mainly consists of an engineered barrier and a natural barrier. Safety evaluation using a numerical model has been performed primarily to evaluate the buffer’s long-term stability. However, although the gas generation rate input for long-term stability evaluation is the critical factor that has the most significant influence on the long-term hydraulic-mechanical behavior of the buffer, in-depth research and experimental data are lacking. In this study, the gas generation rate on the interface between the disposal canister and the buffer material, a component of the engineered barrier, was mainly studied. Gas can be generated between the disposal canister and the buffer material due to various causes such as anaerobic corrosion of the disposal canister metal, organic matter decomposition, radiation decomposition, and steam generation due to high temperature. The generation of gas in such a disposal environment increases the pore gas pressure in the buffer and causes internal cracks. The occurred cracks increase the intrinsic permeability of the buffer, which leads to a decrease in the primary performance of the buffer. For this reason, it is essential to apply the appropriate gas generation rate according to the disposal condition and buffer material for accurate long-term stability analysis. Therefore, the theoretical models regarding the estimation of gas generation were summarized through a literature study. The amount of gas generated was estimated according to the disposal environment and material of the disposal canister. It is expected that estimated values might be used to estimate the long-term stability analysis of buffer performance according to the disposal condition.
        3.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Glass wool is widely used as a typical soundproofing material because it has superior characteristics as a soundproofing material as well as excellent marketability. However, moisture penetration through condensation and cleaning up causes deterioration of insulation and soundproofing performance. In this study, we evaluate the wettability and sound absorption performance when the metal is deposited on the surface of glass wool. The performance is examined based on parameters such as the angle test, drying speed, the absorbency, the moisture content, the wettability. The wettability data shows that Cu coated glass wool is the best performance compaed to Ti coated one. The sound insulation characteristics are also compared by using the impedance tube. At the low frequency range, there is no difference among the test specimens, however, at the frequency above the 250 Hz range, Cu coating shows 10 % better in th sound asorption. Ti coating has almost same to the existing glasss wool performance. It turns out that metal coating on the glass wool seems to be very promising: the metal deposition reveals strong water repellency and sound absorption performance is equivalent to the existing glass wool.
        4,000원
        4.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Glass wool is a fiber made by melting sand and waste glass at high temperature. It has been used as an inorganic fiber for sound absorption, insulation, and non-combustible materials for automobiles, ships, and household appliances. However, the disadvantage comes from the moisture penetration through condensation and cleaning up so that it deteriorates insulation and soundproofing performance. In order to overcome the disadvantages of glass wool, we investigate the water repellency by plating metal on the surface of glass wool with Cu and Ti while coating stability is considered. The thickness of the deposited metal is about 300 nm. The deposition chemicals and the image of the specimen are analyzed by using SEM equipment. The electron microscopic result shows that quite amount of Cu and Ti metals are deposited on the glass wool surface.
        4,000원
        6.
        2015.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        With the stabilization of Korea’s industrialization, it has become interested in the efficient use of rare metals, climate change and industrial environment and safety etc. It is thus making efforts to implement economic policies that address such issues. Therefore it is necessary to understand the demand, supply and use of metal materials. Since 2010, the Korean government has developed the integrated material flow methodology and has been trying to examine the demand, supply and use of metal materials. In 2013, the Korean government surveyed the material flow of chromium. Material flow analysis and environment emission of chromium were investigated 8 steps; (1) raw material, (2) first process, (3) Intermediate product, (4) End product, (5) Use/accumulation, (6) Collection, (7) Recycling, (8) Disposal. Chromium was used for stainless steel, alloy steel, coated sheets, refractory material and coating materials. Recycling was done mainly in use of stainless steel scrap. To ensure efficient use of chromium, process improvement is required to reduce the scrap in the intermediate product stage. In the process of producing of the products using chromium, it was confirmed that chromium was exposed to the environment. It requires more attention and protection against environment emission of chromium.
        4,000원
        8.
        2014.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The object of this paper is to evaluate a working environment noise at manufacturing process of metal material products. To accomplish the object; An employee noise exposure criteria, which is mounted in big size enterprise, was investigated. The noise at the 460 points of the manufacturing process machine in the 38 processes of the 1 factories were measured. The database of the noise was built from the measurement data. The major sound sources and frequency range for the manufacturing process of metal material product machine was investigated. In this study, we compare working environment noise criteria of korean with employee noise exposure criteria
        4,000원
        10.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study attempted to manufacture a Cu-15 at.%Ga coating layer via the cold spray process and investigated the effect of heat treatment environment on the properties of cold sprayed coating material. Three kinds of heat treatment environments, +argon, pure argon, and vacuum were used in this study. Annealing treatments were conducted at /1 hr. With the cold sprayed coating layer, pure -Cu and small amounts of were detected in the XRD, EDS, EPMA analyses. Porosity significantly decreased and hardness also decreased with increasing annealing temperature. The inhomogeneous dendritic microstructure of cold sprayed coating material changed to the homogeneous and dense one (microstructural evolution) with annealing heat treatment. Oxides near the interface of particles could be reduced by heat treatment especially in vacuum and argon environments. Vacuum environment during heat treatment was suggested to be most effective one to improve the densification and purification properties of cold sprayed Cu-15 at.%Ga coating material.
        4,000원
        11.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        파프리카 재배 온실의 피복재 종류에 따른 생산성 차이에 주요 환경요인의 영향 정도를 분석을 위해 유리온실과 플라스틱필름온실의 환경요인 누적데이터를 수집하여 수량과 비교 분석하였다. 유리온실은 외부광량과 수량 간 정의상관을 나타내었고, 100MJ·m-2 당 300~500g·m-2이 증가하는 것으로 나타났고, 적산온도도 같은 경향이었다. 그리고 수량 예측 모델 개발에 있어서는 적산온도가 외부광량보다 가능성을 높게 나타내었다. 최대 순광합성은 유리온실에서 16.83μmol·m-2·s-1로 플라스틱필름온실의 14.93μmol·m-2·s-1보다 13% 정도 높았다. 단위 광량당 생산성은 유리온실에서 플라스틱필름온실보다 46% 정도 높게 나타났다. 그리고 단위 기간당 생산성도 유리온실에서 플라스틱필름온실에서 보다 47%높게 나타났다. 수량에 대한 광, 온도, CO2에 의한 분석 결과 상대수량계수, 수량증가계수, 수량감소계수 및 최대수량계수는 유리온실에서 플라스틱필름온실보다 각각 25%, 73%, 34% 및 49%높게 나타났다. 따라서 유리온실에서 파프리카 재배 시 플라스틱필름온실에 비해 생산성은 높으나, 환경요인의 급격한 변화에 더 민감한 것으로 나타났다.
        4,000원
        13.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        전통 회화 및 단청용 채색 안료 중 녹색을 표현하기 위해 사용된 동록안료의 재료과학적 특성 및 안정성을 알아보기 위하여 염화동(Atacamite), 초산동(Verdigris) 2종의 안료를 이용하여 평가를 진행하였다. 구성광물 분석 결과, K-AA는 아타카마이트(Atacamite)가 주요 구성광물로 천연 광물성 재료로 확인되고 K-VA 는 호가나이트(Hoganite)로 확인되었다. 동록안료의 안정성을 저해하는 요인을 찾고자 UV 노출, CO2/NO2 가스부식 및 염수분사 시험 등의 분석을 실시하였다. 색상 안정성을 가장 크게 저해하는 요인은 두 안료 모두 염수분사 시험으로 시료 표면에 염생성물이 생성되어 변질되는 등 손상이 가중되었다. 또한 대기오염물질인 NO2의 영향도 두 안료 모두 육안으로 인지될 정도로 색이 변하여 주요 손상 요인으로 작용되는 것으로 판단 된다. 특히 K-VA의 경우 K-AA와는 달리 UV 노출 평가 후 녹색에서 흑색으로 변하면서 본래의 색상을 완전히 잃어리는 것으로 K-VA의 주성분인 Hoganite가 UV 노출 후 Tenorite로 물질이 변했기 때문으로 판단된다. 두 안료의 대기환경 영향 평가 결과, K-AA에 비해 K-VA이 대기환경 영향에 상대적으로 취약한 모습을 보였다.
        14.
        2016.10 서비스 종료(열람 제한)
        In the modern construction industry, some methods for enhancing the quality of a building have been sought in various ways. Accordingly, this research team intends to mutually compare the overall kinds of quality of products, such as, the temperature characteristics of PE films and the exposed surface, etc., by applying the single-layered bubble sheet that was developed as a surface curing material for summer to the construction site for a wall-type Apartment which is under construction.
        15.
        2016.04 서비스 종료(열람 제한)
        The objective of this study is the development of an artificial soil composition for vegetation in rock slope condition. In this study, the suitability of artificial soils added the cement-based materials is considered. The results show that the pH value of artificial soil added the micro cement was kept in the range of 7.86 to 8.00.
        17.
        2014.05 KCI 등재 서비스 종료(열람 제한)
        Bacterial cellulose (BC) has played important role as new functional material for food industry and industrial products based on its unique properties. The interest in BC from static cultures has increased steadily in recent years because of its potential for use in medicine and cosmetics. In this study, we investigated culture condition for BC production by Acetobacter sp. F15 in static culture. The strain F15, which was isolated from decayed fruit, was selected on the basis of BC thickness. The optimal medium compositions for BC production were glucose 7%, soytone 12%, K2HPO4 0.2%, NaH2PO4ㆍ2H2O 0.2%, lactic acid 0.05% and ethanol 0.3%, respectively. The strain F15 was able to produce BC at 26℃-36℃ with a maximum at 32 ℃. BC production occurred at pH 4.5-8 with a maximum at pH 6.5. Under these conditions, a maximum BC thickness of 12.15 mm was achieved after 9 days of cultivation; this value was about 2.3-fold higher than the thickness in basic medium. Scanning electron micrographs showed that BC from the optimal medium was more compact than plant cellulose and was reticulated structure consisting of ultrafine cellulose fibrils. BC from the optimal medium was found to be of cellulose type I, the same as typical native cellulose.
        18.
        2010.05 KCI 등재 서비스 종료(열람 제한)
        Automation and robotization has been required in construction for several decades and construction industry has become one of the important research areas in the field of service robotics. Especially in the steel construction, automatic recognition of structural steel members in the stockyard is emphasized. However, since the pose of steel frame in the stockyard is site dependent and also the stockyard is usually in the outdoor environment, it is difficult to determine the pose automatically. This paper adopts the recognition method based on the augmented reality to cope with this problem. Particularly focusing on the light condition of the outdoor environment, we formulated the optimization problem with the constraint and suggested the methodology to evaluate the optimal camera arrangement. From simulation results, sub-optimal solution for the position of the camera can be obtained.
        19.
        2008.10 KCI 등재 서비스 종료(열람 제한)
        인삼은 연작지 재배가 불가능하고 주산지의 우량 예정지 고갈로 인하여 제주도를 제외하고 국내 전국에서 재배하고 있다. 지역별 기후형태가 상이함에도 불구하고 동일한 해가림 구조로 재배하고 있어 일부지역에서 피해가 발생하고 있어 지역에 적합한 표준 해가림 재배기술이 필요하다고 생각된다. 따라서, 본 연구는 남부지역(밀양, 나주, 해남)에서의 적정 해가림구조를 밝히고자 실시하였다. 실험은 2008년 부산대학교 부속농장(밀양)에 묘삼을 이식하였고 해가림 시설은 차광망(검정 차광망), 차광판(비누수 광반사 차광판), 차광지+망(청색 비누수차광지에 검정색 차광망), 차광지(청색 비누수차광지)를 후주연결식으로 설치하여 삼집내 광량과 온도를 측정하였고(Li-cor사의 LI-2000) 광합성속도와 엽록소 형광반응은 생육하고 있는 2년생 인삼을 이용하여 Li-cor의 LI-6400으로 조사하였다. 해가림 자재별 광량은 차광판과 차광지에서 높은 경향을 보였으며, 차광판의 경우 전주에서의 반사광의 유입으로 삼집내 광량이 높은 경향이 있었고, 차광지의 경우 투광량이 높아 광량이 높게 나타냈다. 차광지+망과 차광망에서는 광량이 낮은 경향이었다. 온도는 차광판이 가장 낮은 경향이었는데 이는 직접광이 삼집내로 투과되지 못한 원인으로 사료되며, 다음으로 차광망, 차광지+망, 차광지 순으로 높은 경향을 보였다. 차광지의 경우 투광량이 높아 인삼에서 고온장해가 생기는 현상이 나타났다. 광합성의 경우, 광강도가 증가함에 따라 광합성속도가 증가하는 경향이 있었고, 해가림 자재에 따라 비교하면 차광판에서 높은 경향을 보였으며, 다음으로 차광망과 차광지+망이 높았고, 차광지에서 낮은 경향이었다. 엽록소 형광반응에서 Fo는 차광판에서 낮은 경향이었으며, 다음으로는 차광망, 차광지+망, 차광지 순으로 높은 경향을 보였다. Fv/Fm에서는 차광판에서 높았고, 차광망, 차광지+망, 차광지 순으로 낮은 경향이 있었다. ETR은 차광판에서 가장 높은 경향이 나타냈으며, 다음으로 차광망, 차광지+망, 차광지로 낮은 경향을 보였다.