• Design & Manufacturing
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• 제17권1호
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• pp.1-5
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• 2023

In multi-material injection molding, since two or more materials with different process conditions are used, it is essential to maximize process efficiency by operating the cooling or heating system to a minimum. In this study, Liquid silicone rubber (LSR) that can be cured at a low temperature suitable for the multi-material injection molding was selected and the cure behavior according to the process conditions was analyzed through differential scanning calorimetry (DSC). Dynamic measurement results of DSC with different heating rate were obtained, and through this, the total heat of reaction when the LSR was completely cured was calculated. Isothermal measurement results of DSC were derived for 60 minutes at each temperature from 80 ℃ to 110 ℃ at 10 ℃ intervals, and the final degree of cure at each temperature was calculated based on the total heat of reaction identified from the Dynamic DSC measurement results. As the result, it was found that when the temperature is lowered, the curing start time and the time required for the curing reaction increase, but at a temperature of 90 ℃ or higher, LSR can secure a degree of cure of 80% or more. However, at 80 ℃., it was found that not only had a relatively low degree of curing of about 60%, but also significantly increased the curing start time. In addition, in the case of 110 ℃, the parameters were derived from experimental result using the Kamal kinetic model.

• Journal of Welding and Joining
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• 제33권5호
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• pp.41-46
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• 2015

The snap cure NCP(non-conducive paste) adhesive material is essentially required for the high productivity flip chip bonding process. In this study, the accessibility of DEA(dielectric analysis) method for the evaluation of snap cure behavior was investigated with comparison to the isothermal DSC(differential scanning calorimetry) method. NCP adhesive was mainly formulated with epoxy resin and imidazole curing agent. Even though there were some noise in the dielectric loss factor curve measured by DEA, the cure start and completion points could be specified clearly through the data processing of cumulation and deviation method. Degree of cure by DEA method which was measured from the variation of the dielectric loss factor of adhesive material was corresponded to about 80% of the degree of cure by DSC method which was measured from the heat of curing reaction. Because the adhesive joint cured to the degree of 80% in the view point of chemical reaction reveals the sufficient mechanical strength, DEA method is expected to be used effectively in the estimation of the high speed curing behavior of snap cure type NCP adhesive material for flip chip bonding.

• 한방안이비인후피부과학회지
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• 제29권1호
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• pp.123-130
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• 2016

Objective : The aim of this article is to report the chinese published papers on the results using the direct moxibustion to treat warts.Methods : Searching chinese published papers, we classified the results involved in the direct moxibustion treatment about warts. And analysed remedy methods, periods, cure rate, etc.Results : According to chinese published papers, the direct moxibustion itself may be effective in patients with warts. In all paper, the direct moxibustion showed more than 90% cure rate. The recurrence rate was low.Conclusion : We introduce a variety of wart treatments with the direct moxibustion which is made in China and report meaningful results. We hope to this paper contributes to various studies on cauterization of direct moxibustion.

• 공업화학
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• 제5권4호
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• pp.731-736
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• 1994

DGEBA/MDA/MN계와 이 계에 촉매로서 hydroquinone(HQ)를 첨가한 계의 경화반응 속도론을 Fractional life법 및 Kissinger equation에 의해 연구함으로써 HQ가 경화반응 속도에 미치는 영향을 연구하였다. 경화반응 온도가 증가함에 따라 반응속도는 증가하였고, 반응차수는 약간의 변화가 있을 뿐 경화온도에 따른 경향성은 없었다. 촉매로 HQ를 첨가한 계가 첨가하지 않은 계보다 반응속도는 크게 증가하였고, 활성화 에너지는 13% 감소하였다. 이는 HQ의 히드록시기가 에폭사이드기, 아민기와 반응하여 전이상태를 형성함으로써 에폭사이드 고리를 쉽고 빠르게 개환시켜 주기 때문이다.

• Transactions on Electrical and Electronic Materials
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• 제13권4호
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• pp.204-207
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• 2012

Epoxy nanocomposite was synthesized through the exfoliation of organoclay in an epoxy matrix, which was composed of diglycidyl ether of bisphenol A (DGEBA), 4,4'-methylene dianiline (MDA) and malononitrile (MN). Organoclay was prepared by treating the montmorillonite with octadecyl trimethyl ammonium bromide (ODTMA). The exfoliation of the organoclay was estimated by wide angle X-ray diffraction (WAXD) analysis. In order to measure the cure rate of DGEBA/MDA (30 phr)/MN (5 phr)/organoclay (3 phr), differential scanning calorimetry (DSC) analysis was performed at various heating rates, and the data were interpreted by Kissinger equation. Thermal degradation kinetics of the epoxy nanocomposite were studied by thermogravimetric analysis (TGA), and the data were introduced to the Ozawa equation. The activation energy for cure reaction was 45.8 kJ/mol, and the activation energy for thermal degradation was 143 kJ/mol.

• 한국재료학회지
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• 제9권4호
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• pp.373-377
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• 1999

The cure mechanicsm and cure kinetics of diglycidyl ether of bisphenol A(DGEBA)/4,4'-methylene dianiline(MDA)/nitrile(MN, SN, GN) systems were studied by FT-IR and DSC to develop new applications in the biomedical polymer fields. The network structure of the DGEBA/MDA system was changed to the chain-extended network structure by the addition of nitriles. The reactions contributed to the chain extension were the primary amine-nitrile and hydroxyl-nitrile reactions. The chain-extended network structure could be indirectly proved by the decrement of T\ulcorner and the increment of impact strength with the increasing nitrile content. The cure rate of DGEBA/MDA/nitrile system was lower than that of DGEBA/MDA system due to the disturbance of nitrile group in the reaction of primary amine and epoxide groups.

• Journal of Chest Surgery
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• 제23권5호
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• pp.899-904
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• 1990

One hundred and nine Patients with thoracic empyema were treated at the Chosun university hospital from Jul. 1983 to Sep. 1989. Seventy-nine[72.5%] of the empyemas were adults and 30[27.5%] patients were under fifteen-year children. 29 patients[26.6%] were associated with pulmonary tuberculosis, 23[21.1%] occurred as pneumonia, and 13[11.9%] were unknown. The cardinal symptoms were dyspnea, chest pain, fever, coughing. When used as the initial mode of drainage, repeat thoracentesis was successful in only 46 of 93 cases[49. 5%]. Rib resection, however, provided cure or controlled in 7 cases[100%]. And decortication showed high cure rate in 19 of 24 cases[79.2%] Eventual control or cure of empyema was achieved in 90 patients[89.6%], whereas 7 patients[6.4%] died [3 from their empyema and 4 with empyema as an active problem at the time of death]. of all empyema-caused deaths occurred in patients who underwent chest tube drainage as the most invasive treatment modality. Chest tube drainage was often inadequate and more aggressive management was likely to result in fewer treatment failure and fewer total procedure. Early rib resection was recommended.

• Communications for Statistical Applications and Methods
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• 제24권4호
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• pp.397-419
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• 2017

A four-parameter extended fatigue lifetime model called the odd Birnbaum-Saunders geometric distribution is proposed. This model extends the odd Birnbaum-Saunders and Birnbaum-Saunders distributions. We derive some properties of the new distribution that include expressions for the ordinary moments and generating and quantile functions. The method of maximum likelihood and a Bayesian approach are adopted to estimate the model parameters; in addition, various simulations are performed for different parameter settings and sample sizes. We propose two new models with a cure rate called the odd Birnbaum-Saunders mixture and odd Birnbaum-Saunders geometric models by assuming that the number of competing causes for the event of interest has a geometric distribution. The applicability of the new models are illustrated by means of ethylene data and melanoma data with cure fraction.

• Macromolecular Research
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• 제8권6호
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• pp.285-291
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• 2000

Influence of silane coupling agent, bis-(3-(triethoxisilyl)-propyl)-tetrassulfide, on cure characteristics and bound rubber content of filled styrene-butadiene rubber (SBR) compounds and on physical properties of the vulcanizates was studied. Carbon black-filled and silica-filled compounds were compared. Content of the bound rubber increased with increased content of the silane coupling agent and this trend was shown more clearly in the silica-filled compounds. Optimum cure time of the carbon black-filled compound increased with increase of the silane content, while that of the silica-filled one decreased. Cure rate of the carbon black-filled compound became slower as the silane content increased while that of the silica-filled one became faster. By increasing the silane content, the minimum torque decreased and the delta torque increased. Physical properties of the silica-filled vulcanizate were found to be improved by adding the silane coupling agent. However, for the carbon black-filled vulcanizates, the tensile strength and tear resistance decreased with increase of the silane content. The differences between the carbon black-filled and silica-filled compounds were explained by difference in the reactivities of the fillers with the silane.

• Bulletin of the Korean Chemical Society
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• 제18권11호
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• pp.1199-1203
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• 1997

The investigation of cure kinetics of biphenyl epoxy (4,4-diglycidyloxy-3,3,5,5-tetramethyl biphenyl)-xylok resin system with four different catalysts was performed by differential scanning calorimeter using an isothermal approach. All kinetic parameters of the curing reaction including the reaction order, activation energy and rate constant were calculated and reported. The results indicate that the curing reaction of the formulations using triphenylphosphine (TPP) and 1-benzyl-2-methylimidazole (1B2MI) as a catalyst proceeds through a first order kinetic mechanism, whereas that of the formulations using diazabicyloundecene (DBU) and tetraphenyl phosphonium tetraphenyl borate (TPP-TPB) proceeds by an autocatalytic kinetic mechanism. To describe the cure reaction in the latter stage, we have used the semiempirical relationship proposed by Chern and Poehlein. By combining an nth order kinetic model or an autocatalytic model with a diffusion factor, it is possible to predict the cure kinetics of each catalytic system over the whole range of conversion.