• Title/Summary/Keyword: Low curing temperature

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Physicochemical Properties of Non-Formaldehyde Resin Finished Rayon Fabric and Their Optimal Treatment Condition (비포름알데하이드계 수지 가공제 처리한 레이온직물의 물리화학적 특성 변화와 최적 처리 조건에 관한 연구)

  • Kim, Han-Gi;Yoon, Nam-Sik;Huh, Man-Woo;Jeon, Sung-Ki
    • Textile Coloration and Finishing
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    • v.24 no.3
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    • pp.221-231
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    • 2012
  • Rayon fabrics were treated with some commercial non-formaldehyde and low-formaldehyde resins, and then their effect on the physicochemical properties of fabrics, including formaldehyde release, tear strength, shrinkage, and wrinkle recovery, were investigated respectively. Rayons treated with non-formaldehyde resin, little formaldehyde release was observed. Considering other factors, the optimal concentration of non-formaldehyde resin was shown to be 11-13%, and curing temperature was $170{\sim}175^{\circ}C$. In case of low-formaldehyde type, 9-11% resin concentration and curing temperature of $170{\sim}180^{\circ}C$ were recommended for optimal finishing condition. The choice and combination of resins and catalysts were also important factors, and preliminary considerations before resin-finishing of rayon are also important to get much better results.

Research of Early-age Strength Development Technology for Remove the Steel Form of Large-wide Tunnel Lining Concrete (대단면 터널 라이닝 거푸집의 조기 제거를 위한 초기 강도 발현 기법 연구)

  • Kim, Kwang-Don;Lee, Deuk-Bok
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.5
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    • pp.116-127
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    • 2014
  • The studies were carried out to process one cycle for a day to the large section tunnel lining concrete. Climatic characteristics of the tunnel inside are changed, when the temperature of the concrete placement is low, the mold remove time is increased that the heat of hydration speed be delayed because affects the strength development, to compensate for this, after installing the curing sheet on both sides of the steel form and installation of tunnel entrance, when it comes to providing the additional heat source of $28{\pm}2^{\circ}C$ therein, it was to be achieved early strength development control standards (4.5MPa) presented as a crack control scheme or more, thus, It was able to remove after age of 14hr from mold. On the other hand, under the conditions of $10{\pm}1^{\circ}C$ that a natural curing temperature in the tunnel, it was analyzed must ensure the curing time of 36hr or more after concrete placement. Throughout this study, the concrete strength development and the temperature in the early-age concrete, it can find that reverify the curing temperature is greatly affected, even concrete fly ash is mixed 10%, if it is possible to raise the surface temperature for a predetermined time, is not a problem in the early strength development.

A Study on Micro-patterning used the UV-Curable Resin (UV경화성 수지를 이용한 미세패턴 형성에 관한 연구)

  • 남수용
    • Journal of the Korean Graphic Arts Communication Society
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    • v.19 no.2
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    • pp.68-78
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    • 2001
  • UV-curable resin has the properties of quick-drying, thigh productivity at low temperature, energy savint, space saving, solventless, non-polluting and low-stinking, and thus, UV-curing system has been widely used in the fields of printing inks, adhesives, paints and coating agents. This study has been executed to micro-patterning used UV-curable resin, The micro-patterning properties of this photoresist were investigated under irradiation of UV light low pressure mercury lamp. When the exposed photoresist film was developed by pure water developer, the resolution of this photoresist was about 50$\mu\textrm{m}$.

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Temperature Characteristics depending on the Changes of Surface-coated Curing Methods by using some bubble sheets during winter (동절기 버블시트 표면피복 양생방법 변화에 따른 철근의 온도특성)

  • Lee, Jea-Hyeon;Kyung, Yeong-Hyeok;Lee, Sang-Un;Lee, Joung-Gyo;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.10a
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    • pp.13-14
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    • 2016
  • In the modern construction industry, since numerous skyscrapers have been built, there have been sought for developing various kinds of methods for shortening a construction period. Therefore, many kinds of studies on some kinds of cold-weather concrete have been conducted actively for the purpose of a year-round construction. Accordingly, this research team once developed a double-layered bubble sheet as a surface-coated curing material for winter. And there have been raised some worries that some initial damages to frozen concrete caused by low temperature of reinforcing bars which are exposed out of the wall areas of a wall-type apartment during winter. Therefore, in this study, it is intended to find out clearly whether it is possible for concrete to be damaged initially or not by analyzing the temperature characteristics of the exposed reinforcing bars of the wall areas under the temperature conditions during winter.

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Study on the Fabrication of Embedded Capacitor Films for PWB substrate (PWB 기판용 Embedded Capacitor필름 제작에 관한 연구)

  • 이주연;조성동;백경욱
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2001.11a
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    • pp.21-27
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    • 2001
  • Epoxy/BaTiO$_3$composite film type capacitors with excellent stability at room temperature, uniform thickness, and electrical properties over a large area were successfully fabricated. We fabricated composite capacitor films with good film formation capability and easy process ability, from ACF-resin as a matrix and two kinds of BaTiO$_3$powders as fillers to increase the dielectric constant of the composite film. The crystal structure of the powders and its effects on dielectric constant of the films were investigated by X-ray diffraction. DSC and dielectric properties tests were conducted to decide the right curing temperature and the optimum amount of the curing agent. As a result, the capacitors of $7{\mu}{\textrm}{m}$ thick film with 10nF/cm2 and low leakage current were successfully demonstrated.

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A Study on the Cold Weather Concrete using High Early Strength Concrete (조강시멘트를 이용한 한중콘크리트의 특성평가 연구)

  • 임채용;엄태선;유재상;이종열;이순기;이동호
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.11a
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    • pp.261-264
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    • 2003
  • Cold weather can lead to many problems in mixing, placing, setting time, and curing of concrete that can have harmful effects on its properties and service life. Korean Concrete Institute (KCI) defines cold weather as a period when the average daily air temperature is less $4^{\circ}C$ and recommends to cast concrete with special care such as shielding, heating and so on. The use of high early strength cements may improve the rate of hardening characteristics of concrete in cold weather by making it possible to achieve faster setting time and evolving more hydration heat than ordinary Portland cement. Higher early strength can be achieved using Type III cement especially during the first 7 days. The strength increase property of Type III cement at low temperature was studied. As a conclusion the heat or heat insulation curing period can be reduced to 50~75%. So, it can be used for cold weather concreting to reduce construction cost and extend the construction season.

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Study on the Field Application According to the Early Strength of the Concrete Admixed with Polycarboxylate Superplasticizer (조기강도 콘크리트의 현장적용을 위한 고성능감수제의 종류에 따른 특성 연구)

  • Lee, Jin-Woo;Kim, Kyung-Min;Lee, Young-Hwan;Bae, Yeoun-Ki;Lee, Jae-Sam
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.671-674
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    • 2005
  • In this study, it is examined the properties of early strength of concrete mixed with polycarboxylate superplasticizer. For this experiment, it is analyzed that the slump and strength properties according to the mixture factors, compared with cements and superplasticizers of each company and curing temperature($15,\;20^{\circ}C$). (1) The slump loss of concrete used polycarboxylate superplasticizer(rapid strength type) showed $0.5\~1.5cm$, it is judged that slump loss according to the time lapse can be minimized. (2) The performance of polycarboxylate superplasticizer kept up consistency and accelerated strength development. it is possible to reveal 12MPa within $18\~20$hours at $20^{\circ}C$ curing, but impossible within 24hours at $15^{\circ}C$. (3) It is necessary to studies about rapid strength development in the low temperature.

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($TruNano^{TM}$ processing of color photoresist for the flexible LCD module

  • Lee, Michael M.S.;Moon, Byung-Chun;Bae, Byung-Seong;Kim, Woo-Young;Kim, Nam-Hoon;Cheon, Chae-Il;Kim, Jeong-Seog
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.443-444
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    • 2006
  • We present a low temperature thermal process for the color photoresist on the flexible substrate for the LCD color filter module by the $TruNano^{TM}$ processor in combination with a compositional modification to the conventional color photoresist. By this method the curing temperature can be lowered by more than $100^{\circ}C$, and the curing process time also can be shortening by more than 20 min.

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A study on the Fundamental Properties of Concrete with Belite Cement (벨라이트시멘트 콘크리트의 기초적 성질에 대한 연구)

  • 문한영;문대중;하상욱;김기수
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.04a
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    • pp.167-170
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    • 1998
  • As construction technology advances, most of concrete structures are becoming larger and taller. Therefore, high strength and high quality concrete is necessary for them. Nowadays, the proposal of using belite rich cement is investigated to satisfy high flowing, low heat, and high strength. In this study, the height difference, the falling time and the maximum temperature of concrete using BRC were lower than that of concrete using OPC. Furthermore the compressive strength of concrete using BRC with and without compacting was not different. And the compressive strength of core specimens was higher than that of specimens in water curing. Compared to OPC, there was a good relationship between the curing temperature and the development of strength in BRC.

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Application of Cold Weather Concrete using Accelerator for Freeze Protection (내한촉진제를 사용한 한중콘크리트의 현장적용)

  • Park, Sang-Joon;Won, Chul;Lee, Sang-Soo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.05a
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    • pp.13.2-17
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    • 2003
  • When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods to resolve these problems is to lower freezing temperature of concrete by the use of chemical admixture called Accelerators for Freeze Protection. In this study, it was the results of appling cold weather concrete using Accelerator for Freeze Protection in the Daewoo Trump world field. Before the application of the cold weather concrete using accelerator for freeze protection, we executed the some test in the laboratory and mock-up test in the field. We examined the manifestation of compressive strength complying with the amount of Accelerators for Freeze Protection and curing conditions, and then made a selection of most suitable amount of Accelerators for Freeze Protection.

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