• 한국대기환경학회지
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• 제17권1호
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• pp.97-104
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• 2001

Decomposition of trichloroethlyene(TCE) in electron beam irradiation was examined on order to obtain information on the treatment of VOC in air. Air containing vaporized TCE has been studied in a flow reactor with different reaction environments, at various initial TCE concentration and in the presence and absence of water vapor. Maximum decomposition was observed in oxygen reaction environment and the degree of decomposition was about 99% at 20kGy for 2,000ppm initial TCE. The concentration of TCE exponentially decreased with dose in air and pure oxygen. The effect of water vapor on TCE decomposition efficiency was examined. The decomposition rate of TCE in the presence of water vapor (5,600 ppm) was approximately 10% higher than that in the absence of water vapor. Dichloroacetic acid, dichloroacethyl chloride and dichloroethyl ester acid were identified as primary products of this reaction adn were decomposed and oxidized to yield CO and $CO_2$. Perchloroethylene, hexachloroethane, chloroform and carbon tetrachloride were also observed as highly chlorinat-ed by products.

• 한국수소및신에너지학회논문집
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• 제21권4호
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• pp.328-339
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• 2010

A new gasification model for coal char was developed considering the effects of pore structure and solid reaction product (ash) and compared with conventional models. Among various parameters reflecting microscopic pore structure, initial pore surface per unit volume of char was found to have the largest effect on carbon conversions. Reaction studies showed that the proposed model can predict carbon conversion more accurately over a broader range of reaction degree compared to the conventional models. Therefore the model proposed in this study would be useful for the design of pilot or commercial scale gasifiers.

• 한국미생물·생명공학회지
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• 제23권4호
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• pp.425-431
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• 1995

A kinetic model of the cyclodextrin formation in a heterogeneous enzyme reaction system using swollen extrusion starch as substrate was derived emphasing the structural features of extrusion starch. The degree of gelatinization, the ratio of accessible and inaccessible portion of extrusion starch, adsorption of CGTase on swollen starch, the structural transformation during reaction, and product inhibition caused by produced CDs were considered in deriving kinetic model. Various kinetic constants were also evaluated. The derived kinetic equation was numerically simulated, which result showed that the derived kinetic equations can be used to predict the experimental data reasonably well under the various experimental conditions. Kinetic model can be utilized for the optimization of enzyme reactor and the process development for CD production from swollen extrusion starch.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.9-16
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• 2001

End-gas temperatures were measured using CARS technique in a conventional DOHC spark- ignition engine fueled with PRF80. The measured pressure data were analyzed using band pass filter method. The measured CARS temperatures were compared with adiabatic core temperatures calculated from measured pressures. Significant heating by pre-flame reaction in the end gas zone was observed in the late part of compression stroke under both knocking and non-knocking conditions. CARS temperatures measured at 10 crank angle degree before knock occurrence was higher than adiabatic core temperatures. These results indicate that there exist some exothermic reactions in low pressure and temperature region. CARS temperatures began to be higher than the adiabatic core temperature when the end-gas temperatures reached look. The temperature elevation due to the pre-flame reaction correlated better with CARS temperature than with cylinder pressure.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제20회 KOSCO SYMPOSIUM 논문집
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• pp.85-92
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• 2000

End-gas temperatures were measured using CARS technique in a conventional DOHC spark-ignition engine fueled with PRF80. The measured pressure data were analyzed using band pass filter method. The measured CARS temperatures were compared with adiabatic core temperatures calculated from measured pressure. Significant heating by pre-flame reaction in the end gas was observed in the late part of compression stroke under both knocking and non-knocking condition. CARS temperatures measured at 10 crank angle degree before knock occurrence was higher than adiabatic core temperatures. These results indicate that there exist some exothermic reactions in low pressure and temperature region. CARS temperatures began to be higher than the adiabatic core temperature when the end-gas temperatures reached 700 K. The temperature elevation due to the pre-flame reaction correlated better with CARS temperature than with cylinder pressure.

• 연구논문집
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• 통권29호
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• pp.151-162
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• 1999

In general, manufacturing processes of thermosetting composites consist of mold filling and resin cure. The important parameters used in modeling and designing mold filling are the permeability of the fibrous preform and the viscosity of the resin. To consolidate a composite, resin cure or chemical reaction plays an essential role. Cure kinetics. Therefore, is necessary to quantify the extent of chemical reaction or degree of cure. It is also important to predict resin viscosity which can change due to chemical reaction during mold filling. There exists a heat transfer between the mold and the composite during mold filling and resin cure. Cure kinetics is also used to predict a temperature profile inside composite. In this study, a new scheme which can determine cure kinetics from dynamic temperature scaning was proposed. The method was applied to epoxy resin system and was verified by comparing measurements and predictions.

• Asian Pacific Journal of Cancer Prevention
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• 제14권9호
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• pp.5165-5169
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• 2013

Background: To evaluate the pathological characteristics of invasive margins in early-stage cervical squamous cell carcinomas and their association with other clinicopathological features including clinical outcomes. Materials and Methods: Patients with FIGO stage IB-IIA cervical squamous cell carcinomas who received surgical treatment and had available follow-up information were identified. Their histological slides were reviewed for prognostic variables including tumor size, grade, extent of invasion, lymphovascular invasion, involvement of vaginal margin or parametrium, and lymph node metastasis. The characteristics of invasive margins including invasive pattern (closed, finger-like, or spray-like type), degree of stromal desmoplasia, and degree of peritumoral inflammatory reaction were evaluated along the entire invasive fronts of tumours. Associations between the characteristics of invasive margins and other clinicopathological variables and disease-free survival were assessed. Results: A total of 190 patients were included in the study with a median follow-up duration of 73 months. Tumour recurrence was observed in 18 patients (9%). Spray-like invasive pattern was significantly more associated as compared with closed or finger-like invasive pattern (p=0.005), whereas the degree of stromal desmoplasia or peritumoral inflammatory reaction was not. Low degree of peritumoral inflammatory reaction appeared linked with lymph node metastasis (p=0.021). In multivariate analysis, a spray-like invasive pattern was independently associated with marked stromal desmoplasia (p=0.013), whilst marked desmoplasia was also independently associated with low inflammatory reactions (p=0.009). Furthermore, low inflammatory reactions were independently associated with positive margins (p=0.022) and lymphovascular invasion (p=0.034). The patients with spray-like invasive pattern had a significantly lower disease-free survival compared with those with closed or finger-like pattern (p=0.004). Conclusions: There is a complex interaction between cancer tissue at the invasive margin and changes in surrounding stroma. A spray-like invasive pattern has a prognostic value in patients with early-stage cervical squamous cell carcinoma.

• 청정기술
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• 제19권4호
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• pp.393-400
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• 2013

본 연구에서는 고밀도 폴리에틸렌 제조 공정에서의 부산물인 폴리에틸렌 왁스를 대상으로 무수말레인산(MAH)을 도입하여 솔루션 그라프트 반응을 수행 하였고, 반응 효율에 영향을 끼치는 반응 인자들과 MAH 기능기의 가수분해의 영향에 대해서 조사하였다. 측정 결과, MAH 단량체의 농도가 증가 할수록 그라프트 율은 증가하지만, 전환율은 감소하여 MAH 단량체의 농도가 15 wt% 정도에서 최대 효율을 나타냄을 알 수 있었다. DCP (dicumyl peroxide)와 DTBP (di-tert-butyl peroxide)를 개시제로 사용하여 농도에 따라 그라프트 반응한 결과, 약 0.5 wt%에서 그라프트 율이 최대값에 도달함을 볼 수 있었고, 가교반응은 2% 이하의 낮은 수치를 보임을 확인하였다. 반응온도에 따른 그라프트 율은 반응온도가 높아짐에 따라 증가하는 경향을 보이며, 최대 반응시간은 2 h 내외가 됨을 알 수 있었다. 폴리에틸렌 왁스에 그라프트 된 MAH 기능기는 주로 고리열린 상태로 존재하지만 그라프트 율이 5%이상에서는 고리가 닫힌 상태가 생성되었고, 이에 대한 가수분해 측정결과, 언하이드라이드(anhydride)기가 카르복실(carboxylic acid)기로 전환되는 율이 약 10% 정도로 측정되어, 저분자량 폴리에틸렌 왁스(polyethylene wax, PEW)-g-MAH 물성에 영향을 주는 인자로 여겨졌다.

• Macromolecular Research
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• 제11권5호
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• pp.347-351
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• 2003

The hydrophobic ligand-containing hollow polypropylene (PP) membranes were synthesized by the mutual radiation induced graft copolymerization with glycidylmethacrylate (GMA) onto hollow PP membrane followed by the subsequent functionalization with L-phenylalanine. FT-IR, elemental analysis and UV spectroscopy were utilized to characterize copolymer composition, and degree of grafting, functionalization conversion and ${\gamma}$-globulins adsorption. The degree of grafting on the PP surface increased with the reaction time and total dose of E-beam. In the subsquent functionalization, the amount of L-phenylalanine increased with the increase in the degree of grafting and the degree of conversion was about 30%. The ${\gamma}$-globulins adsorption experiments showed that adsorption capacity had a maximum value at pH 8. The ${\gamma}$-globulins adsorption capacity in the basic pH region was higher than in the acidic pH region.

• Preventive Nutrition and Food Science
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• 제22권1호
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• pp.37-44
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• 2017

Sulfur-containing amino acids play important roles in good flavor generation in Maillard reaction of non-enzymatic browning, so aqueous model systems of glucosamine and cysteine were studied to investigate the effects of reaction temperature, initial pH, reaction time, and concentration ratio of glucosamine and cysteine. Response surface methodology was applied to optimize the independent reaction parameters of cysteine and glucosamine in Maillard reaction. Box-Behnken factorial design was used with 30 runs of 16 factorial levels, 8 axial levels and 6 central levels. The degree of Maillard reaction was determined by reading absorption at 425 nm in a spectrophotometer and Hunter's L, a, and b values. ${\Delta}E$ was consequently set as the fifth response factor. In the statistical analyses, determination coefficients ($R^2$) for their absorbance, Hunter's L, a, b values, and ${\Delta}E$ were 0.94, 0.79, 0.73, 0.96, and 0.79, respectively, showing that the absorbance and Hunter's b value were good dependent variables for this model system. The optimum processing parameters were determined to yield glucosamine-cysteine Maillard reaction product with higher absorbance and higher colour change. The optimum estimated absorbance was achieved at the condition of initial pH 8.0, $111^{\circ}C$ reaction temperature, 2.47 h reaction time, and 1.30 concentration ratio. The optimum condition for colour change measured by Hunter's b value was 2.41 h reaction time, $114^{\circ}C$ reaction temperature, initial pH 8.3, and 1.26 concentration ratio. These results can provide the basic information for Maillard reaction of aqueous model system between glucosamine and cysteine.