• Korean Journal of Environmental Agriculture
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• v.13 no.2
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• pp.191-198
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• 1994

2-Thiophenyltriisopropoxytitanium was prepared in situ by trans-metallization of 2-thiophenyllithium and chlorotitaniumtriisopropoxide. It could be isolated at room temperature and preserved at $-10{\circ}C$ for weeks. The reactivity of 2-thiophenyltriisopropoxytitanium to carbonyl compounds proved to be high. Complete aldehyde-selectivity was observed in competition reactions of 2-thiophenyl-triiso-propoxytitanium with a 1 : 1 mixture of aldehyde and ketone. In the competitive reaction of 2-thiophenyl-triisopropoxytitanium to ketone-ester function, ketone adduct was perfectly obtained.

• Journal of the Korean Chemical Society
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• v.30 no.2
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• pp.248-258
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• 1986

The electronic structures and geometries of model substituted oxiranes, and carbonyl ylides containing cyano, methoxy and thiomethoxy substituents were investigated by MNDO-SCF-MO method. Stabilization and geometries caused by substituents, the ease of formation of carbonyl ylides from oxiranes and the reactivities of the cycloaddition of substituted carbonyl ylides were investigated.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.159-159
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• 2011

최근 여러 화학 반응에 대해서 일층(1L) 그래핀(graphene)이 복층(multi-layered) 그래핀보다 10 배 이상의 높은 반응성을 보인다는 사실이 알려졌다. 본 실험에서는 기판의 편평도와 기판-그래핀 간의 상호작용이 그래핀의 반응성에 미치는 영향을 이해하기 위해서, AFM(atomic force microscopy)과 라만 분광법을 이용하여 그래핀의 기체상 고온 산화반응을 연구하였다. 기계적 박리법을 통해 산화실리콘(SiO2/Si)과 마이카(mica) 기판 위에 고착된 그래핀 시료를 대조군으로 비교하였다. AFM 형상 분석으로부터 편평도가 낮은 산화실리콘 위에서는 그래핀의 두께가 작을수록 산화 속도가 크다는 사실을 확인하였다. 그러나 편평도가 높은 마이카 기판 위에서는 단일층 그래핀의 산화 속도가 산화실리콘 기판 위에서보다 현저하게 감소하고 두 겹 이상의 두께에서는 반응성의 차이가 없음을 발견하였다. 특히 마이카 위의 단일층 그래핀에서는 복층 그래핀과는 달리 산화에 의한 식각이 거의 일어나지 않아 화학적 안정성이 증대되었음을 알 수 있었다. 본 연구는 기판의 표면구조와 상호 작용을 통해 그래핀의 화학적 특성을 조절 할 수 있다는 가능성을 보여 준다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.7
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• pp.1-8
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• 2003

Numerical characteristics of air chemistry associated with hypersonic flows are described and are compared with those of hydrogen oxygen combustion, applying the partially implicit time integration method to air chemistry. This paper reveals that the time integration of air chemistry needs a chemical Jacobian for stable calculations. However the positive real eigenvalues in air chemistry are relatively smaller than those of hydrogen combustion, and the numerical integration is less sensitive than that with combustion. lt is also found that the application of the partia1ly irnplicit method reduces the computing time without numerical instabilities.

• Electronics and Telecommunications Trends
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• v.30 no.6
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• pp.12-20
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• 2015

전기변색기술은 전기화학적 반응으로 물질의 색을 바꾸는 기술이다. 이 반응에는 전자의 이동이 개입되며 전자의 이동에 따른 화학반응은 일반적인 화학반응과 차이를 나타낸다. 산화와 환원이라는 화학반응은 닫힌 회로 내에서 일어나며 오직 계면에서의 전위에 의존하게 된다. 이러한 전기변색기술을 응용한 분야는 자동차용 전기변색 거울, 스마트 윈도우와 같이 상용화에 성공한 분야도 있으며, 앞으로는 투명 디스플레이, 반사형 디스플레이 및 전가자격표시장치 등에 활용이 가능하다. 전기변색기술이 견인하는 세계시장규모는 에너지 절약 및 안전성에 대한 시대적인 요청으로 연평균 성장률 약 21%로 확대되어 2018년에는 약 50억달러의 규모로 성장할 수 있을 것으로 예측된다.

• Journal of the Korean Chemical Society
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• v.25 no.5
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• pp.291-299
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• 1981

A test particle kinetic theory for reaction dynamics in liquids is presented at the repeated ring collision level for the hard sphere model. A kinetic equation for the equilibrium time correlation function of the reactive test particle phase space density is derived and the rate kernel expression for the reversible chemical reaction of the type A +B ${\rightleftharpoons$ C + D in the presence of inert solvent S is obtained by the projection operator method.

• Prospectives of Industrial Chemistry
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• v.18 no.4
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• pp.1-9
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• 2015

최근 신체의 손상된 조직 및 세포를 재생하기 위해 약물 전달이 가능한 생체재료에 관한 연구가 활발히 이루어지고 있다. 이러한 생체재료 개발을 위해 생체적합하며 생분해성이 뛰어난 천연고분자가 큰 각광을 받고 있다. 기존의 약물 전달을 위한 고정화 방법은 화학적 가교가 널리 이용되어 왔으나, 이 방법의 여러 단점들이 보고된 바 있다. 이러한 단점을 극복하기 위해 광반응성 천연고분자를 이용한 약물광고정화 방법이 연구되어 왔다. 본 글에서는 광고정화를 위해 합성되는 여러 광반응성 천연고분자의 종류 및 특성과 생체재료로써의 활용 방안을 소개하고자 한다.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.108-115
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• 2023

Although hydrazine is an excellent liquid propellant, caution is required during storage and handling due to its high toxicity and reactivity. Safety guidelines should be established in consideration of the chemical reactivity by unintended leakage. In this study, the status of hydrazine facilities at launch site and safety standards for storing and handling were investigated and then, the reactivity between chemicals and hydrazine was analyzed. As a result of the analysis, hydrazine has reactivity with the exception of fuel oil. This paper emphasizes the imperative nature of constructing a dedicated hydrazine storage facility. Ensuring compatibility between hydrazine and the materials used in storage containers and handling equipment is crucial to prevent undesired reactions that could compromise safety. It was intended to be used as basic data to secure the range safety when handling hydrazine.

• Journal of the Korean Chemical Society
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• v.52 no.3
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• pp.303-314
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• 2008

The purpose of this study was to understand the experiment for measuring chemical reaction rate by precipitate formation and to develop experiments applying small-scale chemistry. For this study, the experimental method for measuring the effect of concentration and temperature on chemical reaction rates presented in the 10 high school science textbooks were classified by their experimental methods of confirming production. Subsequently, problems observed in carrying out the experiments for measuring chemical reaction rates by precipitate formation frequently presented in the 10 high school science textbooks were analyzed. Experiments applying small-scale chemistry were developed measuring chemical reaction rate by precipitate formation. According to the result of this study, there were some problems in the experimental method of precipitate formation for measuring chemical reaction rates presented in the high school science textbooks. Those problems in the science textbook experiments were insufficient specification of mixing methods of reaction solutions, obscurity of knowing when the character letter X disappeared, time delay in collecting the experimental data, formation of hazardous sulfur dioxide, uneasiness of fixing water bath container, controlling the reaction temperature, and low reproducibility. Those problems were solved by developing experiments applying smallscale chemistry. Presenting the procedure of mixing reaction solutions on the A4 reaction paper sheet made the experimental procedure clearly, using well plates and stem pipette shortened the reaction time and made it possible to continuously collect the experimental data. Furthermore, the quantity of hazardous sulfur dioxide was reduced 1/7 times and the time when the character letter X disappeared could be observed clearly. Since experiments for measuring the effect of concentration and temperature on chemical reaction rates could be performed in 30 minutes, the developing experiments applying SSC would help students understand the scientific concepts on the effect of concentration and temperature on chemical reaction rates with enough time for experimental data analysis and discussion.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.388-396
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• 2008

2 Components polyurethane coatings are widely used for the industrial coating in general because of its excellent film performance and the workability which were brought by the 3 dimensional cross linked chain structures being formed after the reaction between polyol and polyisocyanate. 2 components polyurethane can be classified into alkyd polyol, polyester polyol, acrylic polyol and polyester modified acrylic polyol depending on where it is used. This research was conducted under the conditions below; different chemical compositions of resin for paint, set the same conditions of viscosity, thinner and acid value, set alternative polyols, OH values and catalysts, set alternative polyisocyanate hardeners of the paint, measure the reaction rates and dynamic mechanical characteristics using RPT-3000, Rotation Rheometer, DMA and FTIR. The research found that the reactivity between polyol and isocyanate influences the film performance and workability depending on the catalysts, OH values and chemical compositions. We find out that different reaction rate of acrylic polyol and polyester modified acrylic polyol with poly-isocyanate is not influenced on temperature and catalyst. In addition, reaction speed of high hydroxyl content polyol is faster than low hydroxyl equivalent. These results can improve difficult working condition to apply urethane coating.