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        검색결과 1,732

        901.
        2007.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        실내 공기는 대기와는 달리 실내 건축 자재에서 유래된 물질로 오염될 수 있다. 본 연구는 실내자재인 카펫에서 방출되는 휘발성 유기화합물의 생물학적 영향을 평가하기 위하여 수행되었다. 카펫과 자주달개비 BNL 4430 꽃차례를 환경노출시험용기에 넣고 일정시간 노출을 실시하였고 흡착관의 VOCs에 대한 화학분석을 실시하였다. 화학분석결과 카펫에서는 12종의 VOCs가 방출되는 것이 확인되었으며 이중 스틸렌(71.9μg m-3)과 톨루엔(
        4,000원
        903.
        2007.09 구독 인증기관 무료, 개인회원 유료
        Carbonation in concrete structures has been handled as the most fundamental and critical factor related to the durability of reinforced concrete. As a result, there have been efforts to develop repair materials to control carbonation As one of these efforts, alkali recovery agents have been presented as materials for increasing the re-alkalization and durability of carbonated concrete structures. However, in applying them in the field, the performance and quality of concrete recovered after an alkali recovery agent is applied has not been fully assessed. Therefore, to examine the recovered performance of concrete structures resulting from the application of an alkali recovery agent, the present study assessed the depth of carbonation and the degree of deterioration of 20 years or older reinforced concrete structures, and analyzed the quality of concrete after applying an alkali recovery agent to the structures. This study aimed at providing basic information for the application of alkali recovery agents in the field. In this experiment, alkali recovery agents of the lithium silicate line, which are most common in Korea, were applied and cured using concrete of the same size. The degree of recovery was investigated according to the length of time in the initial curing stage, and based on the investigation, the maintenance performance of the alkali recovery agent was assessed according to the age of exposure to the open air. For these tasks, this experiment sampled concrete of different degrees of deterioration, applied alkali recovery agents to them, and observed re-alkalization and changes in the internal texture of the concrete.
        4,000원
        904.
        2007.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In recent years, the number of complaints about indoor air pollution caused by volatile organic compounds(VOCs) has increased. It is important that evaluating and understanding emission of indoor air pollutant from building materials. The aim of this study was to evaluate emission test methods for liquid phase building materials such as paint, adhesive and sealant, and to determine the emission of total volatile organic compounds(TVOC) from liquid phase building material. The quantity of TVOC emission was measured by a gas chromatography/mass spectrometry (GC/MSD). It was found that liquid phase building materials were classified according to their use and ingredient. The TVOC concentration from oil-based paint was the highest among 8 groups of test materials. The unidentified volatile organic compounds occupied 83.0% of TVOC emission from test materials. The aliphatic hydrocarbons and aromatic hydrocarbons occupied 7.2%, 6.9% of TVOC, respectively. The concentration of TVOC decreased by an increase during emission test period. After 3 days, the concentration of TVOC from paint, adhesive and sealant were about half of the concentration at the first day. The ratio of concentration between 7 days and 1 day was 0.11~0.15 from water-based paint and 0.46~0.48 from epoxy adhesive.
        4,600원
        905.
        2007.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The purpose of this experiment was to find out the effects on metal corrosion of 2 types of tree, 7 types of wood based products and 4 types of cement that is currently being used as internal museum materials. By using the Oddy test as a corrosion test, with the materials that are used in the museum and the metal test pieces(Gilding, Silver, Iron, Bronze, Copper) are exposed in a high temperature( 60℃ ) and humidity for 28 days. After 28 days, we compare and analysis the difference between the metal test piece that was used before and after the test. We found that gilding and bronze did not occur corrosions on the surface but iron(Fe)and copper(Cu) also silver(Ag) had corrosions on the surface in different forms.
        4,000원
        906.
        2007.06 구독 인증기관 무료, 개인회원 유료
        전기변색(electrochromism, EC)소자는 여러 가지 색으로 발색이 가능하고, 낮은 구동전압과 메모리성이 좋은 특징을 갖고 있으나, 내구성이 부족하고 발색 및 소색 속도의 감소, 반복에 따른 완전한 소색과 응답성이 떨어져 실용화에 문제점를 나타내고 있다. 따라서 본 연구에서는 viologen 유도체와 leuco dyes의 안정성 및 내구성을 향상시키기 위하여 이들 색소들의 산화환 원전위와 산화방지제(AO-60)를 사용하였을 때의 cyclic voltammetry와 chronocoulometry를 비교 측정하였다. 그 결과 leuco dye인 CVL과 ODB-2에서는 charge값의 안정성이 10% 이상 증가하였고 Orange-DCF, Red-DCF, Green-DCF에서는 charge값이 5% 이상 상승한 결과를 나타내었다. 모든 색소가 산화방지제를 첨가하였을 경우가 안정한 상태로 내구성을 유지하는 것이 확인 되었다. Benzyl viologen의 경우 AO-60 첨가에 의하여 불안정한 산화상태를 안정화시키는 것을 확인하였다. 따라서 본 연구결과 leuco dye에 의한 EC 소자의 가능성과 칼라화에 대한 가능성을 보임을 확인하였다.
        4,000원
        907.
        2007.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since the 17th century, the society of Joseon dynasty belongs to a period of rapid transition in many fields. As the building is a result to be produced on the basis of a society and economy, the general transition in a society is to be reflected into a process of building construction. Especially, a study on the material supply system of economic base in a process of building construction is one of very important factors in an understanding or estimate of a building. On the premise, this paper is to examine the supply system of iron materials and the tools in the construction of the government managed buildings in the late of Joseon dynasty on a viewpoint of productivity. Construction reports and other documents in those days are examined for the study. Following conclusions have been reached through the study. 1) The general supply method of iron materials for a large-scale government construction was based on 'byulgong', that is, a kind of tribute. 2) Various methods were selected in the supply method of iron materials for government use in the late of Joseon dynasty. The priority order of choice in its government policy was put on an easiness of amount security, on a minimum of expenditure, and on an efficiency of construction execution. 3) The manufacturing technique of weaponry was used in the production method of iron materials and the tools for government use. The cooperation of the official, the army, and the merchant had improved the manufacturing technique of building construction.
        5,500원
        910.
        2007.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 학생들의 과학적 흥미와 호기심을 유발하기 위해 영산강 유역에서 발굴된 구석기시대 유물 유적을 활용하여 지구과학 학습 자료를 개발하였다. 구석기 유물 유적을 활용한 학습 자료는 예비 활동 자료, 박물관에서의 활동 자료, 유적지 답사를 위한 활동 자료, 구석기 유물을 제작하는 활동 자료로 구성되었다. 개발된 학습 자료에 대해 과학교사와 학생의 반응을 살펴보았다. 설문에 응답한 과학 교사들 10명 중 6명은 유물 유적을 활용한 교수 학습 자료가 탐구력 향상에 효과가 있을 것으로 예상하였다. 본 연구에서 개발된 학습 자료는 대부분의 교사들이 정규 수업이 아닌 동아리 활동, 현장학습, 과제부여 등에 적용하는 것이 타당하다고 반응하였다. 구석기 유물 유적을 활용한 학습자료를 적용하는 과정에서, 학생들의 질문 방향이 다양해졌으며 질문하는 횟수도 증가하였다. 유물 유적을 활용한 학습자료는 학생들이 광물과 암석의 성질을 이해하는데 도움이 되었다. 본 학습 자료는 교사들의 학습 주제 선택의 폭을 넓혀줄 것이라 기대된다.
        4,000원
        911.
        2007.04 구독 인증기관 무료, 개인회원 유료
        This paper presents contents of certificates, and use for reference materials. This study also introduces general requirements for the competence of reference material producers. Lastly this paper shows general and statistical principles for certification of reference materials.
        4,200원
        912.
        2007.03 구독 인증기관 무료, 개인회원 유료
        Ordinary concrete uses aggregate sufficiently soaked with water, and is weighed, mixed with other materials and placed in accord with performances required in the construction field. Recently special concrete with high fluidity and durability is required but it is difficult to use top-quality concrete due to lack of high-quality aggregate, delayed transportation because of traffic jam, etc. In addition, sometimes the use of a remicon is inevitable just for small-sized concrete constructions or it is difficult for a remicon to reach remote construction places such as mountainous areas. To solve these problems, this study attempted to pack concrete materials. In other words, it is to instantize concrete. This study dried aggregate, a material of concrete, and compared the change of absorption phase of the aggregate in water and in paste in order to examine the effect of the dryness of aggregate on its absorption rate and, based on the absorption rate, decided water addition ratio necessary for the reduction of unit quantity caused by the use of dry aggregate in designing concrete mixture, and analyzed the properties of unhardened concrete according to water addition ratio in manufacturing concrete using aggregate in the state of absolute dryness and in the state of surface dryness.
        4,000원
        914.
        2007.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The multicolored Asian ladybird beetle (Harmonia axyridis) has been commonly used with biological control agents for control of several kinds of aphids in agroecosystems. Also, environment friendly agricultural materials have been commonly applied in crop fields because the government held down pesticide application and environment friendly agricultures are gradually increased with consumer"s desires. The multicolored Asian ladybird beetles may be directly or indirectly under the influence of environment friendly agricultural materials in crop fields. The insecticidal environment friendly agricultural materials (IEFAMs) might be safe against each developmental stage of multicolored Asian ladybird beetle. Fungicidal environment friendly agricultural materials (FEFAMs) had a miner effect to each developmental stage of multicolored Asian ladybird beetle with the exception of FEFAM A. Environment friendly agricultural materials contained useful soil microorganisms (EFAMSMs) C and H might be down the hatching rate of eggs, and EFAMSM A and F had a killing effect to 1st instar of lady beetles. Environment friendly agricultural materials contained plant extracts (EFAMPEs) A and D might be suffered effect a deathblow of egg hatching with lady beetles. Otherwise, there was a miner effect to lady beetles with the rest of tested environment friendly agricultural materials.
        4,200원
        915.
        2007.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Many kinds of environment friendly agricultural materials were used for the insect pest control and the control of plant diseases, furthermore they support the growth of crops in the greenhouses and the kindly environment friendly farming. Phytoseiulus persimilis might be used for control of two-spotted mites with environment friendly agricultural materials at the same time. For testing the toxicity of environment friendly agricultural materials against to P. persimilis, 61 environment friendly agricultural materials were selected by material contents and using methods. When environment friendly agricultural materials were directly sprayed on P. persimilis, IEFAM C, FEFAM A, EFAMSM A, D, EFAMPE A, EFAMCh B, EFAMME A, and EFAMMo C killed over 90%. However, there was no effects to FEFAM C, D, EFAMSM C, EFAML A, EFAMME C, E, H, J, EFAMMo G and I against P. persimilis. P. persimilis adults were not survived in vial for 48 hours after sprayed and dried with the environment friendly agricultural materials, for examples, EFAMSM I, EFAMME A, EFAMMo A, C, and I. Otherwise, EFAMCh C and EFAMMo B were no effects to P. persimilis. Some environment friendly agricultural materials are of different qualities, and consequently test of their toxity have to necessary.
        4,000원
        917.
        2006.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porous carbon materials were prepared with a thermal treatment of coal tar pitch at 550 in the Ar gas. Growth, merger, and distribution of pore were characterized with scanning electron microscopy as variation ascending temperature gradient and chamber pressure. After graphitizing at the 2600 (1 hr.), walls and connecting parts between pores were investigated with X-ray diffraction patterns. Wall thickness and pore size decreases as increasing ascending temperature gradient, and pore size becomes homogeneous. Graphite quality and thermal conductivity become higher due to the enhanced orientation of walls and connecting parts between pores.
        4,000원
        918.
        2006.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Treatment of water hyacinth with sulphuric acid produces carbonaceous materials that have been used to remove Cu(II) and Cd (II) ions from aqueous solutions. Untreated water hyacinth was also used for the subject of comparison. The textural properties of the carbonaceous materials were determined from nitrogen adsorption at 77 K. The optimum pH for the sorption of Cu (II) and Cd (II) ions on the investigated sorbents was determined. Dynamic adsorption measurements have been taken at 298 K whereas equilibrium measurements were carried out at 298, 313 and 323 K. The adsorption of nitrogen at 77 K on the untreated sample was too low and the surface areas of the treated samples 2, 3 and 4 were found between 70-208 m2/g. The total pore volumes of these samples which were determined for the carbonaceous materials investigated were found to be 0.076-0.140 ml/g. The kinetic adsorption data of Cu (II) and Cd(II) were applicable to both pseudo - first and pseudo-second order but fit more the latter order. The equilibrium adsorption data were found to fit Freundlich and Langmiur equations. The values of DG, DH and DS are all negative indicating the feasibility and the spontaneous nature of the sorption of Cu (II) and Cd (II) ions by the sorbents investigated.
        4,000원
        919.
        2006.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Thin films of carbon-nano materials (CNMs) of different morphology have been successfully deposited on ceramic substrate by CVD at temperatures 800℃, 850℃ and 900℃ using plant based oils in the presence of transition metal catalysts (Ni, Co and Ni/Co alloys). Based on the return and insertion loss, microwave absorption properties of thin film of nanocarbon material are measured using passive micro-Strip line components. The result indicates that amongst CNMs synthesized from oil of natural precursors (mustered oil - Brassica napus, Karanja oil - Pongamia glabra, Cotton oil - Gossipium hirsuta and Neem oil - Azadirachta indica) carbon nano fibers obtained from neem's seed oil showed better microwave absorption (~20dB) in the range of 8.0 GHz to 17.90 GHz.
        3,000원
        920.
        2006.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In architecture, constitutions of space are subjected to the structural material and interior finishing material. Interior environment can exert a great effect on people by means of space constitution. In this study the constitution of space was set to consider five materials: control, wood, steel, wire mesh, and concrete structural material. In this study, experiments with mice, were carried out on condition of each living environment with different living environment using control, wood, steel, wire mesh and concrete structural material. The experiments with mice were made by five-month-old mice(BALB/C) with about 15 grams weight. In order to evaluate the adaptability of the target mice, such variables as body weight, food consumption, and water consumption were monitored against living environment for normal BALB/C mice during the same period. The weight, total foods, and total water consumption were measured under the living environments for 55 days with 2~3 days intervals. To test five different living environments, i.e., control, wood, steel, wire mesh and concrete, 5 mice were allocated for each group. According to the results of this study, the case of wood living environment resulted in a gain in weight with statistical significance. The other side of steel, wire mesh and concrete showed a slight decrease for weight. The weight variation of the experimental mice was assumed under five different living environments that resulted from the stabilized environmental conditions such as the wood living environment.
        4,000원