• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.993-999
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• 2011

The photoreactive prepolymers with multifunctional cinnamate and bisphenol Atype cinnamate groups that could perform photodimerization without photoinitiators were synthesized by the reaction of t-cinnamic acids (CAs) and epoxy resins. Their photocure reaction rates and the extent of reaction conversion were measured with Fourier transform infrared spectroscopy, and these increased with the intensity of UVirradiation. The experimental data of these reaction rates showed the characteristics of nth-order kinetics reaction, and all kinetic constants of each photoreactive polymer with this equation were summarized. Although the GTR-1800-HCA and KWG1-EP-HCA with hydroxyl group substituted cinnamate showed lower reaction conversion rates and rate constant than GTR-1800-CA and KWG1-EP-CAwith an unsubstituted cinnamate group, GTR-1800-MCAand KWG1-EP-MCAwith methoxy group substituted cinnamate showed similar and higher reaction conversion rates than the former, respectively. These results were explained in terms of segmental mobility for photopolymerization by molecular interactions.

• 설비공학논문집
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• 제13권7호
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• pp.637-646
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• 2001

VOC(Volatile Organic Compound) removal characteristics in continuous flow reactors have been numerically investigated. The photocatalytic reaction have been simulated with the binding constant and the reaction rate constant obtained from experimental data for the constant-volume batch reactor, and then VOC abatement in continuous flow reactors with the same conditions as those of batch reactor has been analyzed. The standard 4\kappa-\varepsilon$ model and mass conservation equation have been employed for numerical calculation, and heterogeneous reaction rate has been used in terms of the boundary condition of the conservation equation. in the case of the continuous flow reactor, reaction characteristics have been estimated with various inlet velocities and with different number of baffles. The result shows that the concentration distribution and flow patterns are strongly affected by the inlet velocity, and that with the increased inlet velocity, VOC removal rate is increased, while removal efficiency is decreased. This result may be useful in the design of reactors with improved VOC removal efficiency.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.851-856
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• 2011

본 연구에서는 하수슬러지의 열분해로 촤를 제조하였고, 열분해 반응 조건이 슬러지 촤의 특성에 미치는 영향을 조사하였다. 열분해 온도가 $300^{\circ}C$에서 $800^{\circ}C$로 증가함에 따라 슬러지 char의 비표면적은 증가하였으나, $700^{\circ}C$에서는 일시적으로 감소하였다. 열분해 속도는 char의 비표면적과 기공부피에 미치는 영향이 크지 않은 것으로 나타났다. 반면, 열분해 반응시간이 증가함에 따라 비표면적과 기공부피는 증가하였으나, 평균 기공크기는 감소하는 결과를 나타내었다.

• 대한환경공학회지
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• 제32권11호
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• pp.1046-1053
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• 2010

본 연구의 목적은 생활폐기물에 저품위 무연탄의 혼합 후 열분해 반응 특성을 연구하는데 목적이 있다. 반응 변수로 혼합율, 반응온도, 승온속도에 따른 열분해조건을 고찰하였다. 그 결과, 저품위 무연탄 20 wt.%를 첨가한 혼합 시료가 3,500 kcal/kg 이상의 저위발열량 확보를 위한 최적의 혼합비로 나타났다. 가장 높은 반응속도상수 도출을 위해서는 $700^{\circ}C$의 조건에서 이루어 질 것으로 판단되었다. 또한 시간당 온도의 비가 증가할수록 반응속도상수가 선형적으로 높게 나타났으나, 열분해 시 전력비 상승 및 열분해 생성 char의 수율 등을 고려하여 더 낮은 승온속도에서 열분해가 이루어져야 할 것으로 판단된다.

• 한국환경과학회지
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• 제26권7호
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• pp.859-868
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• 2017

In this study, the reductive dechlorination of triclosan using zero-valent iron (ZVI, $Fe^0$) and modified zero-valent iron (i.e., acid-washed iron (Aw/Fe) and palladium-coated iron (Pd/Fe)) was experimentally investigated, and the reduction characteristics were evaluated by analyzing the reaction kinetics. Triclosan could be reductively decomposed using zero-valent iron. The degradation rates of triclosan were about 50% and 67% when $Fe^0$ and Aw/Fe were used as reductants, respectively, after 8 h of reaction. For the Pd/Fe system, the degradation rate was about 57% after 1 h of reaction. Thus, Pd/Fe exhibited remarkable performance in the reductive degradation of triclosan. Several dechlorinated intermediates were predicted by GC-MS spectrum, and 2-phenoxyphenol was detected as the by-product of the decomposition reaction of triclosan, indicating that reductive dechlorination occurred continuously. As the reaction proceeded, the pH of the solution increased steadily; the pH increase for the Pd/Fe system was smaller than that for the $Fe^0$ and Aw/Fe system. Further, zero-order, first-order, and second-order kinetic models were used to analyze the reaction kinetics. The first-order kinetic model was found to be the best with good correlation for the $Fe^0$ and Aw/Fe system. However, for the Pd/Fe system, the experimental data were evaluated to be well fitted to the second-order kinetic model. The reaction rate constants (k) were in the order of Pd/Fe > Aw/Fe > $Fe^0$, with the rate constant of Pd/Fe being much higher than that of the other two reductants.

• 청정기술
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• 제15권3호
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• pp.186-193
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• 2009

본 연구에서는 상용운전 중에 있는 반연속식 로터리 킬른형 열분해반응기에 지자체에서 발생되는 필름형 혼합 폐플라스틱을 투입한 후 열분해하여 얻은 저급의 열분해유를 세 형태의 반응온도 프로그램에서 분해반응시키고, 여기에서 얻어지는 생성유의 특성을 논의하였다. 원료인 저급 열분해유의 특성은 원소분석 및 발열량 분석, SIMDIST 분석으로 확인하였고, 각 반응온도 프로그램에 따른 분해반응 결과는 각 성분의 수율분포, 액상 생성물의 누적수율과 생성비 등으로 논의하였다. 연구결과는 한 단계 반응온도 프로그램에 비해 다단계 반응온도 프로그램의 경우가 원하는 생성물인 오일수율이 높았고, 상대적으로 잔류물의 수율은 낮게 나타났다. 연속적인 열분해반응에서 반응온도 프로그램은 생성물의 수율분포 등 생성유 특성에 많은 영향을 주었다.

• Korean Chemical Engineering Research
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• 제48권6호
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• pp.752-756
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• 2010

시화/반월 산단 내에서 활성탄 흡착탑을 사용하는 업종 중 도장 공정을 사용하는 대표적인 업체에서 수거한 폐활성탄의 탈착특성을 조사하였다. 탈착특성을 조사하기 위하여 열중량분석기(Thermogravimetric Analyzer)를 사용하였다. 탈착특성 자료를 바탕으로 탈착 특성비교에 중요한 요소인 반응차수와 활성화에너지를 구하기 위하여 Friedman법과 Freeman-carroll법을 사용하였다. 도장 공정에서 수거한 폐활성탄으로 Friedman법을 이용하여 활성화에너지를 계산한 결과 20.6~43.2 kJ/mol을 나타내었으며, Freeman-Carroll법을 이용하여 활성화에너지와 반응 차수를 계산한 결과 활성화에너지는 12.3~26.5 kJ/mol, 반응 차수는 0.1~1.7을 나타내었다.

• 대한토목학회논문집
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• 제30권3D호
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• pp.231-240
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• 2010

교차로 교통사고의 주요 원인은 인적요인에 의한 교통사고가 대부분 차지하고 있어 운전자들의 주행특성 및 교통상황에 따른 심리적 생리적 변화측정을 통해 영향 요인 규명이 필요하다. 이에 본 연구에서는 운전자들의 인적요인을 고려한 개별 교차로 안전성 평가를 위하여 최첨단 계측장비를 활용한 뇌파반응을 측정하고 설문조사를 통해 평상시와 주행 실험시 운전자들의 인지특성 조사를 실시하였다. 교차로 접근시 뇌파변화와 주행실험 인지평가조사 자료의 관계성을 규명하고, 주행실험의 인지평가요인과 생체적 반응 뇌파데이터를 고려한 개별 교차로 안전성 평가 모형을 구축하였다. 그 결과, 교차로의 물리적 특성에 따라 생체반응 뇌파가 다르게 나타나고 인지평가 또한 차이가 있어 주행시 생체반응(뇌파)과정을 통해 인지평가를 하고 있음을 확인할 수 있었다.

• 한국재료학회지
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• 제23권10호
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• pp.574-579
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• 2013

The milling and particulate characteristics of Al alloy-$Al_2O_3$ powder mixtures for a reaction-bonded $Al_2O_3$ (RBAO) process were studied. A commercially available prealloyed Al powder with Zn, Mg, Cu and Cr alloying elements (7475 series) was mixed with a calcined sinter-active $Al_2O_3$ powder and then milled in centrifugal milling equipment for ~48 hrs. The Al alloy-$Al_2O_3$ powder mixtures after milling were characterized and evaluated in various ways to reveal their particulate characteristics during milling. The milling efficiency of the Al alloy increased with a longer milling time. Comminution of the Al alloy particles started with its elongation, showing a high aspect ratio. With a longer milling time, the elongated Al alloy particle changed in terms of its shape and size, becoming equiaxially fine particles. Regardless of the milling efficiency of the Al alloy particles, all of the Al alloy particles repeatedly experienced strong plastic deformation during milling, giving rise to higher density of surface defects, such as microcracks, and leading to higher residual microstress within the Al alloy particles. The chemical reactions, oxidation behavior and hydration behavior of the Al alloy particles and the hydrolysis characteristics of their reaction with the environment were also observed during the milling process and during the subsequent powder handling steps.

• 한국분말재료학회지
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• 제28권1호
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• pp.44-50
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• 2021

Zinc selenide (ZnSe) nanoparticles were synthesized in aqueous solution using glutathione (GSH) as a ligand. The influence of the ligand content, reaction temperature, and hydroxyl ion concentration (pH) on the fabrication of the ZnSe particles was investigated. The optical properties of the synthesized ZnSe particles were characterized using various analytical techniques. The nanoparticles absorbed UV-vis light in the range of 350-400 nm, which is shorter than the absorption wavelength of bulk ZnSe particles (460 nm). The lowest ligand concentration for achieving good light absorption and emission properties was 0.6 mmol. The reaction temperature had an impact on the emission properties; photoluminescence spectroscopic analysis showed that the photo-discharge characteristics were greatly enhanced at high temperatures. These discharge characteristics were also affected by the hydroxyl ion concentration in solution; at pH 13, sound emission characteristics were observed, even at a low temperature of 25℃. The manufactured nanoparticles showed excellent light absorption and emission properties, suggesting the possibility of fabricating ZnSe QDs in aqueous solutions at low temperatures.