• 보존과학회지
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• 제36권1호
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• pp.60-72
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• 2020

The Inscribed stones of Hanyangdoseong has been weathered for a long time because of external environment and living organisms. To establish a long-term conservation-management strategy for the inscription stones, the material characteristics of the inscription stones of Naksan Mountain Area were identified, and its deterioration state was diagnosed. Consequently, it was confirmed that the Inscription stones of Naksan Mountain Area mainly comprised coarse-to medium-grained pinkish granite and biotite granite, and, in part, comprised reddish granite, quartz porphyry, and aplite. Presently, the Inscription stones of Naksan Mountain Area, Hanyangdoseong, is undergoing a considerable decrease in physical properties because of physical, chemical, and biological weathering. Moreover, it has been confirmed that the type of damage, such as blistering, soiling, and dicolouration, on the surface shows a significantly high deterioration rate, and that conservation treatment might be required in future. In addition, because the possibility of damage recurrence is high even after the treatment, the conservation state must be regularly monitored.

• International Journal of Advanced Culture Technology
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• 제8권3호
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• pp.300-306
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• 2020

This study analyzes the distributor's inventory model in a two-stage supply chain consisting of the supplier, the distributor and the end customer. The supplier will allow a credit period before the distributor settles the account with him in order to stimulate the demand for the product he produces. It is also assumed that the distributor pays the shipping cost for the order and hence, the distributor's ordering cost consists of a fixed ordering cost and the shipping cost that depend on the order quantity. The availability of the delay in payments from the supplier enables discount of the distributor's selling price from a wider range of the price option in anticipation of increased customer's demand. As a result, the availability of a credit transaction leads to an increase in inventory levels. On the other hand, in the case of deteriorating products in which the utility of the product perish over time, the deterioration rate with time plays a role in reducing inventory levels. In this regard, we analyze the effect of the length of the credit period and the degree of product deterioration on the distributor's inventory level. For the analysis, we formulate the distributor's annual net profit and analyze the effect of the length of credit period and deterioration rate of the product on inventory policy numerically.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.189-190
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• 2018

KS standards mostly relate to single component material evaluation, so in cases of underground structure environments, most cannot predict the existing composite forms of deterioration, resulting in the applied waterproofing materials becoming unable to respond to these damaging factors. Current domestic waterproofing market in Korea mainly uses single-ply waterproofing materials comprised of coatings or waterproof sheets and two or more-ply composite waterproofing methods. In order to evaluate these types of composite waterproofing systems, a new test equipment and method that incorporates various deterioration conditions (joint displacement, chemical exposure, water pressure etc) was developed. In a comparison testing, the results showed that flexible type materials have higher response performance towards joint displacement than the hardened material.

• Journal of the Korean Wood Science and Technology
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• 제49권5호
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• pp.471-481
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• 2021

This study investigated the hygroscopicity and UV deterioration characteristics of 3 domestic and 4 imported woods using natural oil, stain, and varnish paints. In terms of hygroscopicity, it was found that the hygroscopicity of the painted wood was lower than that of the unpainted wood, and that as the number of coatings increased, the hygroscopicity decreased. In terms of anti-absorption, oil-based chemical paints showed higher resistance than water-based paints, and natural oils showed results comparable to oil-based paints. As for the UV deterioration, the amount of color change of the painted wood was lower than that of the unpainted wood, and there was no significant difference according to the number of times of painting. The amount of color change was found to be low in oil-based paints and hardwoods. Through this study, we confirmed effective moisture blocking and small color changes during painting using paints, and it is believed that wood can be protected from internal and external defects through selective and efficient painting based on data for excellent painting performance.

• Advances in concrete construction
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• 제5권6호
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• pp.671-683
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• 2017

Commonly used concrete in general, consists of cement, fine aggregate, coarse aggregate and water. Natural river sand is the most commonly used material as fine aggregate in concrete. One of the important requirements of concrete is that it should be durable under certain conditions of exposure. The durability of concrete is defined as its ability to resist weathering action, chemical attack or any other process of deterioration. Durable concrete will retain its original form, quality and serviceability when exposed to its environment. Deterioration can occur in various forms such as alkali aggregate expansion, freeze-thaw expansion, salt scaling by de-icing salts, shrinkage, attack on the reinforcement due to carbonation, sulphate attack on exposure to ground water, sea water attack and corrosion caused by salts. Addition of admixtures may control these effects. In this paper, an attempt has been made to replace part of fine aggregate by tailing material and part of cement by fly ash to improve the durability of concrete. The various durability tests performed were chemical attack tests such as sulphate attack, chloride attack and acid attack test and water absorption test. The concrete blend with 35% Tailing Material (TM) in place of river sand and 20% Fly Ash (FA) in place of OPC, has exhibited higher durability characteristics.

• 한국인쇄학회지
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• 제30권1호
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• pp.59-69
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• 2012

This study is Long term preservation measures which is closely related to preserving paper records, record condition evaluation, preservation measure and is conducted as follows. As for Means to Evaluate the Deterioration and Damaged Conditions of Records, research and analysis has been made on the contamination and deterioration examples such as damage, dry, stapler, metal, contamination, acidification which are the characteristics of paper record damage types. The of Paper record is one of the key procedures to evaluate the record material and its physi-chemical status in many criteria and to suggest the best preservation method. Between 1970 and 2000, the main record materials was fine paper and OMR paper along with partly newspaper and coarse paper, whereas the main recording material was ball point pen. Overall damage and deterioration status is, for record materials between 1940 and 1960, high deterioration was found and in urgent need for preservation measure and more damages are caused by tapes, staplers and metals. As for records after 1970, there is light deterioration but needs preservation process. There are approximately 3 million records produces before 2000, and assuming that there are 30 pages per record and that 30% has been damaged or deteriorated, 27 million pages are subject to preservation process. Among damaged or deteriorated records, there are large number of records impossible to go through deacidification process so manual preservation and restoration process is necessary as well. Securing manpower having preservation and restoration skills as well as preservation equipment(deacidification process, preservation and restoration) is in urgent need.

• 한국공간구조학회논문집
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• 제11권1호
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• pp.97-104
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• 2011

본 연구에서는 막구조 건축물의 유지관리를 위한 막재의 표면 및 코팅층의 열화진단을 수행하였다. 막재는 내화학성능 및 내부식 성능을 포함하는 내구성능이 가장 중요시 되는 재료이다. 일반적으로 대공간 건축물의 지붕재료로 사용되는 막재의 유지관리 진단항목은 막재의 표면 열화진단, 막재의 코팅층 열화진단, 막재의 코팅층 및 섬유포 사이의 열화진단, 막재 전면에 걸친 열화진단, 로프의 열화진단, 보강벨트의 열화진단, 커버고무 등의 열화진단 등으로 대별된다. 본 연구는 대공간 건축물의 지붕재료로 많이 사용되는 PVDF계 막재를 대상으로 표면 및 코팅층의 열화도 진단 결과를 보고한다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.220.2-220.2
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• 2011

Biodiesel and biodiesel blend fuel are receiving increasing attention as alternative fuels for diesel engines without substantial modifications. Biodiesel fuels and blending have been widely studied and applied in diesel engine because of biodiesel's lower sulfur, lower aromatic hydrocarbon and higher oxygen content. Biodiesels have the potential to be oxidized in different condition. It has reported that oxidation deterioration of biodiesel is different in the condition of storage and oxidation causes chemical property change of methyl esters. Sunlight intensity, temperature, material of container and contact surface with oxygen are key dominant factors accelerating oxidation deterioration. In this study, we chose temperature among key oxidation conditions and metal container filled with biodiesel was heated at about $110^{\circ}C$ for 10 days in order to accelerate oxidation deterioration. To better understand the effect of biodiesel blends on emission, steady state tests were conducted on a heavy duty diesel engine. The engine was fueled with Ultra Low Sulphur Diesel(ULSD), a blend of 10% and 20%(BD10, BD20) on volumetric basis, equipped with a common rail direct injection system and turbocharger, lives up to the requirements of EURO 3. The experimental results show that the blend fuel of normal biodiesel with BD10 and BD20 increased NOx. The result of PM was similar to diesel fuel on BD10, but the result of PM on BD20 was increased about 63% more than its of diesel. The blend fuel of Oxidation biodiesel with BD10 and BD20 increased NOx as the results of normal biodiesel. But PM was all increased on BD10 and BD20. Especially THC was extremely increased when test fuel contains biodiesel about 140% more than its of diesel. Through this study, we knew that oxidation deterioration of biodiesel affects emission of diesel engine.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.69-72
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• 2003

Volatile organic compounds (VOC) cause air pollution problem and deterioration of atmosphere of petrochemical and fine chemical plants. Hybrid process of membrane and cold-condensation were developed and it effectively removed and recycled the VOC. Operation parameters of the process were optimized to attain hish removal and recycle of VOC. Composite membranes for organic vapor separation were developed in this work by PDMS coating and plasma polymerization on polypropylene and polysulfone support membranes. PDMS and various silicone monomers were tested for several organic vapors such as benzene, toluene, TCE, and HCFC, which are produced in petrochemical and fine chemical industry and causes air pollution problems if are released to atmosphere. Composite membranes prepared in this work showed appreciable performance in terms of organic vapor removal and reuse. Performance variation of the membranes was correlated with their surface characteristics.

• 한국구조물진단유지관리공학회 논문집
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• 제17권6호
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• pp.145-152
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• 2013

콘크리트는 대표적인 건설재료로서 지난 19세기 후반 이후 각종 구조물의 축조에 활용되고 있다. 콘크리트는 일반적으로 적절한 설계 및 시공 규정을 준수한다면 내구성을 확보하는 것으로 인식되었으나, 구조물의 사용 과정 중에 겪게 되는 각 종 외적 작용으로 인해 수명단축 및 성능저하 현상이 빈번히 나타나고 있으며 더욱이 노후화에 따른 콘크리트 구조물의 성능 저하는 억제할 수 없으며 결국 콘크리트 구조물의 유지관리 측면에서 보수 및 보강은 필요한 실정이다. 본 연구에서는 기존의 보수 및 보강공법의 성능을 개선하고자 콘크리트 표면의 강화 및 특히 내화학 성능의 향상을 위하여 개발되어진 내화학성적층보강공법 (Chemical Resistance of Laminating Reinforcement Method : CRM)을 적용하였다. 따라서 본 연구에서는 콘크리트 시험체에 대한 다양한 내구성 시험을 통하여 일반적인 보수 및 보강공법을 적용한 시험체 와의 비교분석을 통하여 결과를 도출하였으며 시험결과, 기존 보수 및 보강공법보다 CRM을 적용한 콘크리트 시험체의 내구성능이 향상되었는데 이는 에폭시계의 내산섬유보강 및 2중의 섬유계의 보강시트로 인한 적층효과로 판단된다.