• Title/Summary/Keyword: 경화수지처리

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Evaluation of Electrical Degradation in Epoxy Composites by DC Dielectric Breakdown Properties (DC 절연파괴 특성을 이용한 Epoxy 복합체의 전기적 열화 평가)

  • 임중관;박용필
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2002.11a
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    • pp.779-783
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    • 2002
  • The dielectric breakdown of epoxy composites used for transformers was experimented and then its data were simulated by Weibull distribution probability. As a result, first of all, speaking of dielectric breakdown properties, the more hardener increased the stronger breakdown strength at low temperature because of cross-linked density by the virtue of ester radical. And the breakdown strength of specimens with filler was lower than it of non-filler specimens because it is believed that the adding filler forms interface and charge is accumulated in it, therefore the molecular motility is raised, the electric field is concentrated, and the acceleration of electron and the growth of electron avalanche are early accomplished. In the case of filled specimens with treating silane, the breakdown strength become much higher since this suggests that silane coupling agent improves interfacial combination and relaxs electric field concentration. Finally, from the analysis of weibull distribution, it was confirmed that as the allowed breakdown probability was given by 0.1%, the applied field value needed to be under 21.5MVcm.

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Density, Bonding Strength, Bending strength and Decay Resistance of Radiata Pine Laminated Veneer Lumber (라디에타소나무 단판적층재의 밀도·접착·강도성능 및 내부후성)

  • Suh, Jin-Suk;Lee, Dong-Heub;Hwang, Won-Joung;Oh, Hyung-Min;Park, Young-Ran;Kang, Sung-Mo
    • Journal of the Korean Wood Science and Technology
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    • v.39 no.4
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    • pp.344-350
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    • 2011
  • In this study, LVLs of radiata pine were fabricated with non-preservative treated veneers, CuAz treated veneers, and ACQ treated veneers, using aqueous vinyl urethane adhesive and phenol modified resorcinol resin adhesive. Then density gradient, bonding strength, bending properties and decay resistance of LVLs were evaluated. As results, the cone-shaped and higher density gradient pattern was found in layer close to glueline. After cyclic water boiled test, the LVL bonded with aqueous vinyl urethane resin adhesive was delaminated in all layers or partly delaminated including check, chasm in glueline layer. In the case of LVL bonded with phenol modified resorcinol resin adhesive, despite slight cupping due to great glueline stress and vertical check between glueline layers, it was observed that the bonding strength to delamination was higher, owing to most absence of delamination through overall glueline. On the other hand, in the decay test, mass loss by brown rot fungi was greater than white rot fungi in LVL bonded with aqueous vinyl urethane resin adhesive. However, in LVL bonded with phenol modified resorcinol resin adhesive, the mass loss by brown rot fungi was slight and non-preservative treated LVL was low. The mass loss of preservative-treated LVL was 0 (zero), showing the high decay resistance effect.

A Study on the Analysis of Outside Mural Paintings treated in Maitreya Hall of Geumsan-sa Buddhist Temple, Korea (금산사미륵전 외벽화 보존처리된 벽체의 분석 연구)

  • Han, Kyeong-Soon;Lee, Sang-Jin;Lee, Haw-Soo
    • Journal of Conservation Science
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    • v.26 no.4
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    • pp.445-458
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    • 2010
  • The deterioration and structural damage such as exfoliation, cracks, and separation of painted layer on the wall paintings of Maitreya Hall in Geumsan-sa temple have been accelerated since it was re-positioned to the original place after the dismantling from the building in 1993. The examination of which result and analysis described in this study, is a preliminary survey for establishing conservation plan of the wall paintings. It aimed at the understanding of the physical and chemical characteristics of the materials applied in the 1993 conservation. The research focused on the south walls which displayed the worst condition compared to other walls. Samples for the examination for the understanding of micro-structure, chemical composition, cristalisation, and particle distribution, were collected for finishing, middle, and consolidated layers of the walls between pillars and the ones between brackets. Those samples were collected from separated fragments of the walls. The sample analysis displayed that: 1. the 1993 conservation used the similar type of weathered soil as the original for the finishing layer, and such soil and sand for the middle layer; 2. those walls are composed of a group of mineral particles which are relatively equal in size and shape and in their distribution; 3. the mineral particles were cohered forming solid aggregate due to the application of acrylic resin for the reinforcement on the wall. The main composition of crystalisation on the first and the second reinforcement layers of the back walls were lime plaster ($CaSO_4{\cdot}2H_2O$). The overall examination confirmed that the priority of the future conservation treatment should be given to the removal of the first and the second layers of reinforcement and the treatment on the back walls which were partially consolidated.

Design of Hard Coating Resin for In-mold Decoration (IMD) Foil and Effects of EB Irradiation on IMD Foil Layers (In-mold Decoration(IMD) 포일용 경질 코팅 수지 설계 및 전자빔 조사가 IMD 포일 구성층에 미치는 영향)

  • Sim, Hyun-Seog;Kim, Geon-Seok;Shin, Ji-Hee;Lee, Kwang-Hee
    • Polymer(Korea)
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    • v.36 no.3
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    • pp.268-274
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    • 2012
  • The silane coupling agent, 3-(trimethoxysilyl)propyl methacrylate (${\gamma}$-MPTS), was grafted on the surface of alumina nanoparticles. We used the surface modified nanoparticles in the hard coating layer for in-mold decoration (IMD) foils and evaluated the coating properties such as hardness and anti-abrasion property. The effects of electron beam (EB) irradiation on color layer and anchor layer of IMD foils were observed through the difference in color and the cross-cut tape test, respectively. Also, cure kinetics as studied quantitatively under various reaction temperatures by analysis of surface properties and Fourier transform infrared (FTIR) spectroscopy. From these results, we constructed database for the commercial exploitation of EB curing system.

A Study on the Process Conditions of ACA( Anisotropic Conductance Adhesives) for COG ( Chip On Glass) (COG(Chip On Glass)를 위한 ACA (Anisotropic Conductive Adhesives) 공정 조건에 관한 연구)

  • Han, Jeong-In
    • Korean Journal of Materials Research
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    • v.5 no.8
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    • pp.929-935
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    • 1995
  • In order to develop COG (Chip On Glass) technology for LCD module interconnecting the driver IC to Al pad electrode on the glass substrate, Anisotropic Conductive Adhesive(ACA) process, the most promising one among COG technologies, was investigated. ACA process was carried out by two steps, dispensing of ACA resin in the bonding area and curing by W radiation. Load on the chip was ranged from 2.0 to 15kg and the chip was heated at about 12$0^{\circ}C$. In resin, the density of conductive particles coated with Au or Ni at the surface were 500, 1000, 2000 and 4000 particles/$\textrm{mm}^2$, and the diameter of particles were 5, 7 and 12${\mu}{\textrm}{m}$. As a result of the experiments, ACA process using ACA particle of diameter and density of 5${\mu}{\textrm}{m}$ and 4000 particles/$\textrm{mm}^2$ respectively shows optimum characteristic with the stabilzed bonding properties and contact resistance.

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A Study on Physicochemical Properties of Epoxy Coatings for Liner Plate in Nuclear Power Plant (원자력발전소 격납건물 철재면 에폭시 도장시편의 물리화학적 특성 평가)

  • Lee, Jae-Rock;Seo, Min-Kang;Lee, Sang-Kook;Lee, Chul-Woo;Park, Soo-Jin
    • Applied Chemistry for Engineering
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    • v.16 no.6
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    • pp.809-814
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    • 2005
  • In this work, the thermal properties of epoxy coating system on the liner plate in the containment structure of nuclear power plants had been examined by irradiation and design basis accident (DBA) conditions. The effect of immersion in hot water on adhesion strength of the coating system had been also studied. The glass transition temperature ($T_g$) and thermal stability of ET-5290/carbon steel A 32 epoxy coating systems were measured by DSC and TGA analyses, respectively. Contact angle measurements were used to determine the effect of immersion on the surface energetics of epoxy coating system, with a viewpoint of surface free energy. Adhesion tests were also executed to evaluate the adhesion strength at interfaces between carbon steel plate and epoxy resins. As a result, it was found that the irradiation led to an improvement of internal crosslinked structure in cured epoxy systems, resulting in significantly increasing the thermal stability, as well as the $T_g$. Also, the immersion in hot water made a role in the post-curing of epoxy resins and increased the mechanical interlocking of the network system, resulting in increasing the adhesion strength of the epoxy coating system.

Study of the method of production of excavated arrow bundle and its conservation treatment (발굴 출토 화살다발 제작기법 연구 및 보존처리)

  • Lee, Byeonghoon;Choi, Bobae;Huh, Ilgwon
    • Conservation Science in Museum
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    • v.25
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    • pp.9-26
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    • 2021
  • This paper describes the production methods that were originally used for an arrow bundle excavated from a Bronze Age residential area in Auraji in Jeongseon, Gangwon-do Province and the conservation treatment process that it subsequently underwent. An arrow conventionally consists of an arrowhead and a shaft. It is rare to excavate a shaft along with an arrowhead in a complete form since the shaft is made of organic materials. Notably, the arrow bundle from the Auraji site is of great significance as it shows traces of tangless stone arrowheads attached to charred shafts and offers an important case of the split end of a piece of a tree being inserted into an arrowhead. For a further examination of the characteristics of the arrows from Auraji, microscopic investigation was conducted and the type of wood used for the arrow shafts was examined. The sequence and direction of processing and the particle sizes of the grinding tools were revealed through the analysis of traces of grinding on the stone arrowheads. The shaft is presumed to have been made from a green length of three-year-old willow (Salix spp.). A curing agent with a high degree of waterproofing and reversibility was used during the on-site curing process according to demands of the surrounding environment, and a technique that the authors call the "Bridge" method was used for emergency collection of the relics. Once the bundle was transferred to the conservation treatment lab, reinforcing materials were carefully chosen as it was important not to damage the relics during the process of turning them for the repair of their reverse sides. For this purpose, artificial clay was selected since it can safely bear a load and has excellent physical properties. Finally, detached parts were rejoined, the relics and their surrounding materials were cleaned, and the bottom sides were finished with epoxy resin prior to the display of the relics at the museum.

Relationship between Compressive Strength and Dynamic Modulus of Elasticity in the Cement Based Solid Product for Consolidating Disposal of Medium-Low Level Radioactive Waste (중·저준위 방사성 폐기물 처리용 시멘트 고화체의 압축강도와 동탄성계수의 관계)

  • Kim, Jin-Man;Jeong, Ji-Yong;Choi, Ji-Ho;Shin, Sang-Chul
    • Journal of the Korea Concrete Institute
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    • v.25 no.3
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    • pp.321-329
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    • 2013
  • Recently, the medium-low level radioactive waste from nuclear power plant must be transported from temporary storage to the final repository. Medium-low level radioactive waste, which is composed mainly of the liquid ion exchange resin, has been consolidated with cementitious material in the plastic or iron container. Since cementitious material is brittle, it would generate cracks by impact load during transportation, signifying leakage of radioactive ray. In order to design the safety transporting equipment, there is a need to check the compressive strength of the current waste. However, because it is impossible to measure strength by direct method due to leakage of radioactive ray, we will estimate the strength indirectly by the dynamic modulus of elasticity. Therefore, it must be identified the relationship between of strength and dynamic modulus of elasticity. According to the waste acceptance criteria, the compressive strength of cement based solid is defined as more than 3.44 MPa (500 psi). Compressive strength of the present solid is likely to be significantly higher than this baseline because of continuous hydration of cement during long period. On this background, we have tried to produce the specimens of the 28 day's compressive strength of 3 to 30 MPa having the same material composition as the solid product for the medium-low level radioactive waste, and analyze the relationship between the strength and the dynamic modulus of elasticity. By controling the addition rates of AE agent, we made the mixture containing the ion exchange resin and showing the target compressive strength (3~30 MPa). The dynamic modulus of elasticity of this mixtures is 4.1~10.2 GPa, about 20 GPa lower in the equivalent compressive strength level than that of ordinary concrete, and increasing the discrepancy according to increase strength. The compressive strength and the dynamic modulus of elasticity show the liner relationship.

A Study on the Fallow of Depopulation Area in Rural Korea - The Case Study of Deoggali, Sangju Gun - (과소농촌지역(過疎農村地域)의 휴경요인(休耕要因)과 유형(類型) - 경북 상주시 사벌면 덕기리의 사례연구 -)

  • Lee, Han-Bang
    • Journal of the Korean association of regional geographers
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    • v.7 no.3
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    • pp.74-90
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    • 2001
  • Serious depopulation has occurred since the rapid economic growth after $1965{\sim}1995$. As a result, nowadays most of mountain villages face difficulty in maintaining and managing their settlement, because of the elderly population and the extremely small size of the settlement. Population change is understood as the origin of depopulation problems and the criterion for the depopulation. This study aims to identify the problems of over-depopulation in rural Korea and to classify the patterns and process of follow and to provide policy alternatives. It consists with the three parts : identifying the problems of over- depopulation, classifying the socio-economic factors of fallow land, analyzing a detailed case study of follow land in over-depopulation rural area-Sangju Gun and to provide policy alternatives. The results are summarizes as follows: 1) In the study area, the amount of fallow and abandoned cultivated land has increased since 1975. With the increased urbanization, the cause of the increase in fallow and abandoned cultivated-land is the labor shortage of quantity and quality. The underlying reasons for the abandonment of farmland are poor field conditions and the lack of rented farmland. 2) The secondary cause is a relative labor shortage through specialization into intensive horticulture. In the study area, specialization into pear requires intensive labor input. It has caused a relative labor shortage. 3) The third causes are landowner and the lack of rented farmland due to labor shortage. The declining of agriculture and forestry have caused out-migration and increased non-residents' landowner. 4) The fallow patterns are devided into two types the less favored farmland fallow type, non-residents' landowner(out-migrator) fallow type. The significant causes of the increase in fallow and abandoned cultivated land are the labor shortage, intensive farming, less favored farmland conditions, non-residents' landowner. The factors which caused the follow processes in Korea are socio-economic factors (labor shortage, intensive farming, less favored farmland conditions) and cultural factor(non-residents' landowner, psychological ties between rural areas and urban areas).

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Studies on Increase of Timber Strength with Electric Osmosis of Resin (수지(樹脂)의 전기삼투(電氣滲透)에 의(依)한 목재강도(木材强度) 증대(增大)에 관(關)한 연구(硏究))

  • Park, Young Kwan;Kim, Kap Duk
    • Journal of Korean Society of Forest Science
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    • v.12 no.1
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    • pp.23-29
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    • 1971
  • In order to see a possible strengthening of much injection of synthetic resin into timber by way of electric osmosis, Authors examined the change of the bending strength of the sample timber piece after being injected. 1. Three kinds of sample tree species, Pinus rigida, Magnolia and Populus were used and the size of the sample timber pieces was $30mm{\times}30mm{\times}330mm$. 2. Each of the electric osmosis was made with 250V of D. C. voltage and $0.01A/cm^2$ of the current for 2 hours and the experimenter hardened the injected resin by putting the sample in an oven of $120^{\circ}{\pm}2^{\circ}C$ temperature for 24 hours. 3. The size of the test sample piece for bending strength measurement was $20mm{\times}20mm{\times}320mm$ and Amsler type universal timber test machine was used for the measurement. 4. The strength difference between treated and untreated samples was as follows. Pinus rigida high sig. Magnolia None Sig. Populus Sig.

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