• Title/Summary/Keyword: fast cure

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Cure Behavior, Thermal Stability and Flexural Properties of Unsaturated Polyester/Vinyl Ester Blends (불포화 폴리에스터/비닐에스터 블렌드의 경화 거동, 열안정성 및 굴곡 특성)

  • 이종문;조동환
    • Polymer(Korea)
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    • v.27 no.2
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    • pp.120-128
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    • 2003
  • The effects of catalyst, accelerator and blend composition on the cure behavior of unsaturated polyester resin (UPE), vinyl ester resin (VE) and their blends were studied using differential scanning calorimetry(DSC). The DSC thermograms strongly depend on each variable. The result shows that the small exothermic peak at 115$^{\circ}C$ is due mainly to the UPE component in the UPE/VE blends and the large one at 134~138 $^{\circ}C$ is due mainly to the VE component. The results also indicate that the change of the DSC thermogram measured after each blend was exposed to high temperature 18$0^{\circ}C$ and the fast curing conditions of a few tens seconds provide useful information on understanding the thermal processing of a blend at high speed. The measurements of resin flow time represent that there are three distinct stages of cure in the UPE/VE blends: induction, transition and macro-gelation stages, as similarly reported for UPE by others earlier. The thermal stability and flexural properties of the cured UPE are significantly improved by blending it with the VE, depending on the composition.

Development and Application of Fast-cured AKD Emulsion (급속반응형 AKD Emulsion의 개발 및 적용)

  • Choi, Won-Hee;Shin, Jong-Ho;Park, Min-Tae
    • Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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    • 2002.11a
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    • pp.218-226
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    • 2002
  • 제지분야에서 중성 사이즈제로 광범위하게 사용되어지는 AKD emulsion의 사이징 효과의 발현속도가 낮은 단점을 보완하기 위하여, 기존 AKD emulsion에 추가 투입 사용함으로써 발현속도를 높여줄 수 있는 AKD 급속 반응형 정착제, 그리고 정착제를 사용하지 않는 초지 시스템에서도 급속 경화가 가능한 급속 반응형 AKD emulsion을 개발 하였다. AKD 급속 반응형 정착제의 투입량 및 종이 건조시간에 따른 사이징 효과를 상용화된 정착제와 비교하였으며 이 결과로부터 보다 빠른 사이징 효과발현을 확인하였다. 정착제를 사용하지 않는 시스템에서 급속반응형 AKD emulsion의 사이즈도 급속발현 효과를 확인하기 위하여 상용화된 emulsion과 사용량에 따른 사이징 효과와 건조시간에 따른 사이징효과를 비교함으로서 사이즈도의 급속 발현을 확인 할 수 있었다.

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Tuning Exothermic Curing Reaction of Hydrogenated Bisphenol A Epoxy Resins for Stone Conservation (석조문화재 보존.복원에 적용될 에폭시 수지의 경화 시 반응열 제어 및 안정성 향상 연구)

  • Choi, Yong-Seok;Park, You-Jin;Kang, Yong-Soo;Won, Jong-Ok;Kim, Jeong-Jin;Kim, Sa-Dug
    • Journal of Conservation Science
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    • v.28 no.2
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    • pp.131-139
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    • 2012
  • The exothermic cure kinetics of epoxy resin was controlled by hardener containing fast and slow curing agents. The epoxy risen comprises hydrogenated bisphenol A-based epoxide (HBA), fast curing agent (FH) and slow curing agent poly(propyleneglycol)bis(2-aminopropylether) (SH). Talc was used as an inorganic additive. In the process of curing, cure kinetics along with temperature was monitored by differential scanning calorimeter (DSC) and thermocouple to show that the temperature increase was well controlled by adjusting the hardener mixture. Additionally, bending and tensile strengths of the epoxy/talc composites were also measured to be lower and higher with the amount of the talc inorganic additive, respectively. It is thus concluded that the increase in the temperature during exothermic curing reaction and mechanical properties of epoxy resins are tuned by optimizing hardener mixture for successful stone conservation.

A Study on Positive Effect affecting Medical Development with Integration of Oriental-western Medicine in China (최근 중국의 중.서의 결합에 관한 연구 -- 의학발전에 미치는 긍정적인 영향을 중심으로 --)

  • Lee, Jun-Mu;Lee, Seon-Dong
    • The Journal of Korean Medicine
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    • v.17 no.2 s.32
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    • pp.17-33
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    • 1996
  • Chinese medical science with long history has experience and theory of cure and prevention as well as the perfect different system with western medicine. Western medical science also was introduced in recent times and has been used in fast development in China extensively. Therefore only China that coexist oriental and western medicine is used the term, the integration of oriental and western medicine. Its object is to make better treatment and prevention value with utilizing their strong point and weak point. That is, its great principle is to develop through interchange together without interference in the other science. For mutual growth of both medical science, national concern and support, medical staffs, administrative system and a lot of fruits, etc should be arranged simultaneously. This paper was obtained the as follows. 1. The system of public health administration is composed a sanitary department for a western medicine and a managing agency for a chinese one in the center. There are each local organization under the control both agency in the locality 2. The importance of the integration of chinese and western medicine is to get the merit of special chinese system through the interchange of both medicine and union with modem science and chinese pharmacy. 3. It is the long term and great project. So its important study field is illness treatment and cure, oriental medical remedy and theory, acupuncture and moxibution etc. 4. It makes steady progress in all the healthy medical field. It has studied its foundation, the education of medical staffs, scientific study and strengthening of skill management considerably. 5. The products are the development of new chinese medicines and many researches about traditional chinese medical science. In brief, the integration of chinese and western medical science is the historical stream. Besides it will contribute toward the cure and prevention of human illness for future 21 century.

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Study on Cure Behavior of Low Temperature and Fast Cure Epoxy with Mercaptan Hardener (Mercaptan 경화제에 의한 저온속경화 에폭시의 경화거동에 관한 연구)

  • Eom, Se Yeon;Seo, Sang Bum;Lee, Kee Yoon
    • Polymer(Korea)
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    • v.37 no.2
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    • pp.240-248
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    • 2013
  • The curing behaviors of diglycidyl ether of bisphenol A (DGEBA) with mercaptan hardener were studied by the comparison with amine-adduct type hardener. Curing behaviors were evaluated by DSC at dynamic and isothermal conditions. In the DSC, the dynamic experiments were based on the method of Kissinger's equation, and the isothermal experiments were fitted to the Kamal's kinetic model. Activation energy of epoxy/amine-adduct type hardener was ca. 40 kcal/mol. As the functional group of mercaptan hardener, -SH increased, on epoxy/mercaptan hardeners, the activation energies decreased from 28 to 19 kcal/mol. Epoxy/amine-adduct type hardener was initiated at $90^{\circ}C$ or higher. However, epoxy/mercaptan hardeners reduced the initiation temperatures below $80^{\circ}C$ and shortened the durations of curing reaction within 10 min. We found out that the reaction kinetics of epoxy with mercaptan hardener followed the autocatalytic reaction models, and the maximum reaction rates were shown at the conversions of 20~40%.

Fuzzy Logic Based Relaying Using Flux-differential Current Derivative Cure for Power Transformer Protection

  • Kwon, Myoung-Hyun;Park, Chul-Won;Suh, Hee-Seok;Lee, Bock-Gu;Shin, Myong-Chul
    • Journal of the Korean Institute of Intelligent Systems
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    • v.8 no.5
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    • pp.72-82
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    • 1998
  • Power transformer protective relay should block the tripping during magnetizing imrush and rapidly operate the tripping during internal faults. But traditional approaches maloperate in the case of magnetizing inrush with low second harmonic component and internal faults with high second harmounic component. To enhance the fault detection sensitivities of conventional technuques, flux-differential current derivative curve by fuzzy theory approaches is used. This paper deals with fuzzy logic based protective relaying for power transformer. The proposed fuzzy based relaying algorithm consisits of flux-differential current derivative curve, harmonics restraint, and precentage differential characteristic curv. The proposed relaying was tested with relaying signals obtained from Salford EMTP simulation package and showed a fast and accurate trip operation.

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A Technology Convergent Medical Service Engineering Model based on the Dynamic Innovation Theory (동태적 혁신이론 기반의 기술 융합 의료서비스 공학모델)

  • Kim, Jong-Ho
    • IE interfaces
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    • v.21 no.2
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    • pp.209-220
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    • 2008
  • Recently, innovative medical services are fast emerging, which include customized medical services based on bio-informatics, composition of cure and well-being exploiting ubiquitous technology, hospital supply chain management using RFID, and so forth. However, conventional approaches for new service development hardly give us systematic model to analyze and produce creative medical services. Because most of them are static and concentrate on microscopic tools or techniques. Thus, it is highly desirable to suggest an integrative framework to organize the whole transformation process from technology to medical service. The objective of this study is to propose a medical service engineering model based on the dynamic innovation theory. The proposed model contains objectives of service system, strategies of hospital, stages, activities required to deal with medical service life cycle, which incorporates the acquisition of new technology, transformation to the product, penetration into market, and adoption of consumers. In addition, the usefulness and applicability of the newly proposed model are provided using catholic medical center example.

An Experimental Study on Improving Water Tightness of Concrete Surface Applied High Growth Organic Crystalization Material (고성장 유기결정체의 성장 특성을 이용한 콘크리트 표층부의 수밀성 개선에 관한 연구)

  • Song Je-Young;Kang Hyo-Jin;Oh Sang-Keun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.817-820
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    • 2004
  • Our country was much developments in change of construction environment along with fast economy development. But, various problems that must think in problem of safety and quality were appeared. Constructions which build through rapid economy development are getting many social criticisms to problem of crack and water leakage at use process. Is situation that huge repair expense to cure this is engaged. Safety problem of construction is indicated socially through various media mediums again.

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Studies on the Chemical Treatment of Silica for Synthetic Rubber Reinforcement (II) -Silica Treatment by LBR-MDI- (합성(合成)고무 보강제(補强劑) Silica의 화학처리(化學處理)에 관(關)한 연구(硏究) (II) -MDI 처리(處理) Silica의 LBR처리(處理)-)

  • Jin, Je-Yong;Kim, Hong-Seon;Choi, Sei-Young
    • Elastomers and Composites
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    • v.30 no.3
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    • pp.207-217
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    • 1995
  • The reinforcement of Inorganic filler silica treated with LBR-MDI In SBR vulcanizates were Investigated. The inorganic filler silica treated with MDI on unmodified surface and that of silica treated by MDI was retreated with LBR. The charateristics of vulcanization, physical properties, surface properites and dynamic properties were investigated after mixing those silica with SBR and unmodified silica with SBR. Rheometric studies of the vulcanization showed that S-series has fast scorch $time(t_{10})$ and an optimum cure $time(t_{90})$ in the SBR compounds. And it was turned out that SBR vulcanizates compounded with LBR treated silica was better than any other componnds in hardness, tensile strenght, 100 300% modula and elongation. We could confirm that urea bonding is formed from IR spectrum. We concluded that L-series shows the best reinforcement effect in SBR vulcanizates.

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CASE REPORTS: TREATMENT OF ORAL SOFT TISSUE LESIONS AND WOUNDS WITH HIGH FUNCTIONAL TOOTH PASTE MADE FROM NANOEMULSION GEL (나노에멀젼 젤로 만든 고기능성치약을 이용한 구강 연조직 창상 및 병소에 대한 치험례)

  • Chae, Chang-Hoon;Choi, Dong-Ju;Shim, Hae-Young;Byun, Eun-Sun;Hong, Soon-Min;Park, Yang-Ho;Park, Jun-Woo
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.33 no.6
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    • pp.694-700
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    • 2007
  • It is a gel type high functional toothpaste containing vitamin C, E, propolis extract and the rest of herb with a nanoemulsion state. Vitamin C, E is known as the material with an eminent anti-oxidation effect. Propolis is known as the material with an antimicrobial and anti-inflammatory effect. We have been succeeding in making nanoemulsion of vitamin C, E and propolis through the high pressure homogenizer using stable oil and lecithin and the gel type high functional tooth paste were made from nanoemulsion of vitamin C, E and propolis. We observed the process of wound protecting effect and cure effect for a wound of soft tissue, gingival tissue and mucous membrane showing ulcer and inflammation in oral cavity after applying a gel type high functional toothpaste to patient. As a result, the wound were healed very fast and any side effects were not shown. We confirmed that a gel type high functional toothpaste with nanoemulsion of vitamin C, E and propolis extract has good effect not only for wound healing but also for treatment of ulcer-like lesion in oral cavity. So we report our cases with review of literatures.