• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2374-2382
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• 2002

Aluminum alloy/aramid fiber reinforced plastic(Al/AFRP) laminates consists of high strength metal(A15052) and laminated aramid fiber with structural adhesive bond. The mixture ratio effect of epoxy resin curing agent accelerator on the tensile strength and T-peel strength characteristic in Al AFRP laminates were investigated in this study. The epoxy. diglycidylether of bisphenol A(DCEBA), It'as cured by methylene dianiline(MDA) with or without an accelerator(K-54). Eight different kinds of resin mixture ratios were selected for the test , five kinds of Al/AFRP laminates were named as Al/AFRP(1) and three others of Al/AFRP laminates were named as Al/AFRP(2). The comparison of tensile strength and T-peel strength with variation of resin mixture ratio were studied. Respectively. Al/AFRP(1) and Al/AFRP(2) indicated approximately 6.0 times and 7.0 times more improved maximum tensile strength in comparison with those of monolithic A15052. Al/AFRP(2) indicated approximately 1.5 times more impoved maximum T-peel strengths in comparison with those of Al/AFRP(1). As results. Al/AFRP(2) turned out to have more effective characteristics on the tensile strength and T-peel strength than those of Al/AFRP(1).

• Polymer(Korea)
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• v.34 no.3
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• pp.215-219
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• 2010

Nitrile rubber (NBR) composites were prepared using the commercially avaliable rubber compounding process with Cloisite$^{(R)}$ 10A or carbon black as fillers. When Cloisite$^{(R)}$ 10A was used as a filler in the NBR composites, the mechanical properties, oil resistant, and oxygen barrier were better than those for carbon black composites. In cure characteristics of NBR/clay composites, scorch time and curing time were reduced. It was found that alkyl ammonium ion inserted in Cloisite$^{(R)}$ 10A was considered as an accelerator of vulcanization for NBR composites.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.915-920
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• 1994

The thermal properties of Iliglycldyl ether of bisphenol A(DGEBA)-4, 4'-methylene dianiline (MDA)system with SN(Succinonitri1e) as a chain extender and HQ(Hydroquinone) as a reactive accelerator were investigated. Glass transition ternperature(Tg), heat deflection ternperature(HDT) and decomposition ternperature(Td) were measured with IiQ content in wh~ch SN : HQ content was fixed 4 : 1. Tg and HIIT were slightly decreased with increasing IIQ content. Td was stable at about $360^{\circ}C$ according to the changing HQ content and cure temperature.

• Journal of the Korea Concrete Institute
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• v.15 no.4
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• pp.541-548
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• 2003

This study is to investigate the temperature curve and development of compressive strength due to the curing conditions and to evaluate the optimum curing condition of test specimens showing the same development of strength to that of real structures in cold weather. The results of temperature curve with curing conditions in mock-up tests showed the trend of decrease plain concrete with insulation form, plain concrete with heating, concrete with accelerator for freeze protection, and control concrete in turn. The strength development of plain concrete of inside and outside of shelter showed the very slow strength gains due to early freezing, but that of concrete with accelerator for freeze protection showed the gradual increase of strength with time. From this, it is clear that accelerator for freeze protection has the effects of reducing the freezing temperature and accelerating the hardening under low temperature. Strength test results of small specimens embedded in members and located in insulation boxes at the site are similar to that of cores drilled from the members at the same ages, thus it is clear that these curing methods are effective for evaluation in-place concrete strength.

• 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.

• Food Industry And Nutrition
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• v.10 no.3
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• pp.5-9
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• 2005

비만은 제2형 당뇨병, 심혈관계 질환, 그리고 암을 비롯해 각종 질병의 위험인자로 작용한다. 비만은 낮은 수준의 전신성 염증상태로 간주되며, 비만시 증가하는 염증성 분자는 제2형 당뇨병 또는 동맥경화등의 비만성 질병 발생과정에 깊이 관여한다. 따라서, 염증제어는 비만성 질환제어를 위해 매우 중요하다. 지방세포 비대에 따른 지방세포 기능이상은 아디포사이토카인의 분비 이상을 초래하고, 비만성 질환의 발생 및 촉진자로 작용한다. 비만환자에게서의 MCP-1과 같은 염증성 아디포사이토카인의 분비 제어는 비만성 질환을 예방하거나, 또는 질병 발생 및 진행을 지연시키는 전략적 가치가 있을 것으로 사료된다. 지방세포가 분비하는 케모카인 가운데 MCP-1은 비대한 지방조직내로의 대식세포의 침윤 및 활성화를 유도하며, 특히 비대한 지방조직에서의 염증반응을 증폭시키는 역할을 한다. MCP-1은 내 장지 방조직에서 특히 그 분비량이 높았고, 따라서, 복부비만 관련 질환의 타겟분자로서 가치가 있을 것으로 생각된다. 또한, MCP-1 작용을 저해하는 항염증성 phytochemical은 비만으로 인한 염증성 질환의 발생을 지연시키거나, 즉 예방적인 차원에서 유용할 것으로 사료된다.

• Journal of the Korean Wood Science and Technology
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• v.12 no.4
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• pp.36-46
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• 1984

In order to investigate the inhibitory index (I) and the effects of hot water extraction treatments and addition of accelerators on the index in hardening of Korean lignocellulosics, portland cement (Type I) and water system, hydration tests were carried out on 8 Korean lignocellulosics, namely, Pinus densiflora, Pinus rigida, Pinus koraiensis, Abies holophylla, Larix leptoiepis, Populus alba-glandulosa, rice husk and rice stalk with or without hot water extraction or chemical additives. The inhibitory index of Pinus densiflora and Pinus rigida found to be suitable under limited conditions for composite without any treatment. With hot water treatment rice husk, Pinus koraiensis, Larix leptolepis, and A hies holophylla were reclassified from not suitable to suitable under limited conditions. Combining hot water extraction with chemical addition of accelerator, calcium chloride of magnesium chloride, Populus alba-glandulosa, Larix leptolepis, and Pinus rigida became highly suitable.

• Korean Journal of Materials Research
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• v.4 no.8
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• pp.888-894
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• 1994

In detail of fracture and mechanical properties to carbon/BMI$(\pm 45^\circ)_{2s}$ discusses by acoustic emission and tensile testing. The bismaleimide resin from Boots Technochemie Co. was toughened by TM 120 from same Co. The weight proportions of TM 120 were fixed as 0, 5, 10, 15, 20, 25phr. The 0.2phr of 1, 4-diazobicyclo-(2, 2, 2)-octane(DABC0) was used as the accelerator. The used carbon fiber was T300 from Toray Co. The optimum additional proportion of TM120 was proved as 20phr by mechanical testing and at the same time by the results of acoustic emission. toughening agent gives significant influences on the fracture phenomena and mechanical strength.

• Journal of Technologic Dentistry
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• v.19 no.1
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• pp.43-54
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• 1997

This investigation is carried out of inqurie into the effects of the accelerator on the setting time and haedness when it is used with plaster products. Plaster($\beta$), dental hard stone($\alpha$), and limproved dental hard stone($M{\alpha}$) are selected as the objects of the investigation, since they are most common materials for dental plaster products. Setting time is gauged by means of Vicket Needle and Gilmore Needle, and hardness is gauged by means of Brinell and Vicket Hardness machines. Samples of each material are made in the standerd water powder ratio and with the accelerator repectively, Every material is tested five times each. The results of the tests are as fallow : 1) In each case the setting time is shortened when the accelerator is used. 2) Of the three materials the hardness of the plaster was lowest A($\beta$) < B($\alpha$) < C($M{\alpha}$)} 3) In each case the hardness of the samples made in the standard water powder ratio were higher than that of the sample made with the accelerator. A1 > A2 ; B1>B2 ; C1>C2 4) Final Conclusion : Higher quality cast is expected when it is made in the standard water powder ratio.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.4
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• pp.450-456
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• 2022

In this study, as the preliminary research on the development of heating concrete members, compressive strength and accelerated chloride diffusion behavior in the mortar specimens containing C₁₂A₇ based binder and anhydrite was evaluated. Also, the effect of the mixing ratio of the citric acid based retarder was quantitatively evaluated by considering 4 levels of mixing cases. The compressive strength tests of the mortar specimen were performed referred to KS L ISO 679, and the accelerated chloride diffusion tests were performed according to NT BUILD 492 and ASTM C 1202. In the mortar with 0.3 % of retarder, the highest compressive strength was evaluated, which showed the strength development ratio of 127.6 % compared to the control case. It was considered that engineering performance was improved by effectively securing setting and curing time with 0.3 % of citric acid based retarder. As the result of the evaluation of the passed charge and the accelerated chloride diffusion coefficient, the evaluation results had similar behavior with the results of compressive strength. According to the previous study, the strength behavior and the chloride diffusion behavior had a linear relationship. The mixture showing the highest strength performance had the highest durability performance for chloride ingress, and the heating concrete development from this study will be performed in the future.