• Bulletin of the Korean Chemical Society
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• 제29권12호
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• pp.2365-2367
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• 2008

• Bulletin of the Korean Chemical Society
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• 제20권4호
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• pp.392-394
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• 1999

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.96.2-96.2
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• 2008

• Bulletin of the Korean Chemical Society
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• 제14권3호
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• pp.307-309
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• 1993

• 한국자동차공학회논문집
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• 제8권4호
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• pp.51-58
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• 2000

It is well known that the majority of the emissions measured from vehicle exhaust in the US Federal Test Procedure(FTP-75) are emitted during the first 60 seconds. This paper describes an experimental study on SI engine emissions reduction after cold start with interval secondary air injection and coolant control. Secondary air injection after cold start to reduce exhaust emissions causes an exothermic reaction at the exhaust port and gives sufficient air to the catalyst. For that reason engine-out emissions oxidized in the exhaust port and the rapid heating of a catalytic converter after cold start with CSAI and ISAI are estimated. The influence of the coolant temperature on SI engine emissions has been estimated. In the present studycoolant control of the cylinder head tempeature is used to investigate the effect of coolant temperature on SI engine emissions. The results show that engine-out hydrocarbon and carbon monoxide emissions are considerably reduced with interval secondary air injection and coolant control.

• 터널과지하공간
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• 제12권2호
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• pp.107-114
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• 2002

터널 2차라이닝은 지반하중의 합리적인 산정기준의 부재와 보수적 경향의 지반이완하중법이 적용되고 있기 때문에 과다한 경향으로 보강되고 있는 실정이다. 2차라이닝에 고려되는 주요하중으로는 지반이완하중과 수압을 들 수 있으며, 배수터널의 경우에는 지반하중이 가장 큰 하중이 된다. 터널 주변 지반에 별도의 외력이 작용하지 않는다면, 2차라이닝에 작용하는 하중의 직접적인 원인은 1차지보재의 지지력 저하이다. 따라서, 2차라이닝의 설계시에는 지반과 1차지보재와의 상호작용을 고려한 합리적인 해석방법이 요구된다. 본 논문에서는 단순한 질량-스프링 모델을 통하여 지반-1차지보재-2차라이닝의 상호작용을 개념적 모델로 설명하였으며, 이를 원형터널에 대한 이론해석을 통하여 지반-1차지보재-2차라이닝 의 상호작용에 대한 하중전이 특성을 입증하였다. 그리고, 복잡한 터널해석조건에 대한 본 모델의 적용성을 검토하기 위하여 수치해석법의 적용성을 검증하였다.

• 방사성폐기물학회지
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• 제19권2호
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• pp.271-278
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• 2021

In this study, a chlorination technique for recycling Li₂ZrO₃, a reaction product of ZrO₂-assisted rinsing process, was investigated to minimize the generation of secondary radioactive pyroprocessing waste. It was found that the reaction temperature was a key parameter that determined the reaction rate and maximum conversion ratio. In the temperature range of 400-600℃, an increase in the reaction temperature resulted in a profound increase in the reaction rate. Hence, according to the experimental results, a reaction temperature of at least 450℃ was proposed to ensure a Li₂ZrO₃ conversion ratio that exceeded 80% within 8 h of the reaction time. The activation energy was found to be 102 ± 2 kJ·mol^-1·K^-1 between 450 and 500℃. The formation of LiCl and ZrO₂ as reaction products was confirmed by X-ray diffraction analysis. The experimental results obtained at various total flow rates revealed that the overall reaction rate depends on the Cl₂ mass transfer rate in the experimental condition. The results of this study prove that the chlorination technique provides a solution to minimize the amount of radioactive waste generated during the ZrO₂-assisted rinsing process.

• The Korean Journal of Pain
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• 제28권2호
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• pp.153-155
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• 2015

We are reporting a rare case of a delayed hypersensitivity reaction caused by hyaluronidase allergy following a lumbar transforaminal epidural block. Using an intradermal skin test, we have provided evidence that the systemic allergic reaction resulted from hypersensitivity to hyaluronidase. To our knowledge, this is a rare case of a delayed hypersensitivity reaction to epidural hyaluronidase, comprised of an initial exposure to hyaluronidase with no subsequent allergic response in prior block followed by a subsequent delayed reaction to hyaluronidase during a second epidural block.

• Bulletin of the Korean Chemical Society
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• 제5권5호
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• pp.187-190
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• 1984

Reaction of acid chlorides with primary alcohols, secondary alcohols, and aryl alcohols in the presence of a catalytic amount of zinc chloride gave the corresponding esters in high yields, whereas the reaction with tertiary alcohols failed to give the esters due to the fast solvolytic reactions of tertiary alcohols with hydrogen chloride generated from the reaction. The use of molecular sieves as a scavenger for hydrogen chloride was found to be moderately effective in the reaction of mesitoyl chloride with tertiary alcohols. Reaction of acid chlorides with thiols in the presence of zinc chloride in acetonitrile proceeded cleanly, yielding the corresponding thiol esters in high yields.

• Archives of Plastic Surgery
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• 제43권1호
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• pp.40-45
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• 2016

Background Bioabsorbable plates and screws are commonly used to reduce maxillofacial bones, particularly in pediatric patients because they degrade completely without complications after bone healing. In this study, we encountered eight cases of a delayed foreign body reaction after surgical fixation with bioabsorbable plates and screws. Methods A total of 234 patients with a maxillofacial fracture underwent surgical treatment from March 2006 to October 2013, in which rigid fixation was achieved with the Inion CPS (Inion, Tampere, Finland) plating system in 173 patients and Rapidsorb (Synthes, West Chester, PA, USA) in 61 patients. Their mean age was 35.2 years (range, 15-84 years). Most patients were stabilized with two- or three-point fixation at the frontozygomatic suture, infraorbital rim, and anterior wall of the maxilla. Results Complications occurred in eight (3.4%) of 234 patients, including palpable, fixed masses in six patients and focal swelling in two patients. The period from surgical fixation to the onset of symptoms was 9-23 months. Six patients with a mass underwent secondary surgery for mass removal. The masses contained fibrous tissue with a yellow, grainy, cloudy fluid and remnants of an incompletely degraded bioabsorbable plate and screws. Their histological findings demonstrated a foreign body reaction. Conclusions Inadequate degradation of bioabsorbable plates caused a delayed inflammatory foreign body reaction requiring secondary surgery. Therefore, it is prudent to consider the possibility of delayed complications when using bioabsorbable plates and surgeons must conduct longer and closer follow-up observations.