• 한국응용과학기술학회지
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• 제29권1호
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• pp.149-158
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• 2012

본 연구에서는 올레산을 표면개질제로 사용하여 수열법을 통해 수산화 마그네슘을 합성하였다. 수산화 마그네슘은 알카리 조건에서 올레인산과의 반응을 통해 표면 개질된 마이크로 크기의 플레이크 형상을 갖는다. 수열합성에서 수산화 마그네슘 입자 생성의 조건은 pH, 온도 그리고 반응시간이 표면개질과 입자 형상의 주요 변수임을 확인하였다. 생성된 수산화 마그네슘 입자는 FE-SEM, XRD, FT-IR 그리고 TGA를 통해 확인하였다. 유기 용매 내에서의 분산성의 확인은 개질되지 않은 수산화 마그네슘과의 침전 테스트 비교를 통해 확인하였다.

• 한국표면공학회지
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• 제41권4호
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• pp.174-179
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• 2008

Nanosize tungsten powder was synthesized by ultrasonic spray pyrolysis method through a solution containing ammonium metatungstate hydrate $[(NH_4)_6W_{12}O_{39}{\cdot}H_2O]$ and reduction treatment. It was expected the improvement of mechanical properties due to increasing surface free energy and surface activity. Starting solutions with each concentration, reaction temperature and reduction treatment were significantly influenced on the formation of tungsten size and phase. It was found that particle size was decreased with concentration of starting solution and surface tension were decreased. The particle size was increased at thermal decomposition temperature above $600^{\circ}C$ by neck growth of interparticles. Tungsten particles were formed by reduction reaction in atmosphere of hydrogen gas at the temperature above $700^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• 제27권12호
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• pp.1976-1980
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• 2006

We have calculated the reaction probability and the reaction cross-section of the $N(^4S)+O_2(X^3\sum_{g}^{-})\;\rightarrow\;NO(X^2\Pi)+O(^3P)$ reaction by the quasiclassical trajectory method with the 6th-order explicit symplectic algorithm, based on a new ground potential energy surface. The advantage of the 6th-order explicit symplectic algorithm, conserving both the total energy and the total angular momentum of the reaction system during the numerical integration of canonical equations, has firstly analyzed in this work, which make the calculation of the reaction probability more reliable. The variation of the reaction probability with the impact parameter and the influence of the relative translational energy on the reaction cross-section of the reaction have been discussed in detail. And the fact is found by the comparison that the reaction probability and the reaction cross-section of the reaction estimated in this work are more reasonable than the theoretical ones determined by Gilibert et al.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1674-1681
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• 2015

This paper presented an improved analytical method for calculating armature-reaction field in the surface-mounted permanent magnet machines accounting for opening slots. The analytical model is divided into two types of subdomains. The current of the armature is centralized in the center of the slots. The field solution of each subdomain is obtained by applying the interface and boundary conditions of the model. Two 30-pole/36-slot prototype machines with different slot-opening width are used for validation. The FE (finite element) results confirm the validity of the analytical results with the proposed model. The investigation shows that the wider the slot-opening width is, the smaller the peak value of radial and circumferential components of flux density, and the analytical armature-reaction field produced by centralized current in the slots is similar with the armature-reaction field produced by distributed current in the slots in the FE.

• 한국세라믹학회지
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• 제37권7호
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• pp.721-725
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• 2000

In this study, the dispersion stability of nano-sized CeO2 particles, synthesized by hydrothermal method in aqueous was evaluated from observing the surface potential behavior of CeO2 particle synthesized by solid state reaction. The isoelectric point(IEP) of nano-sized CeO2 synthesized by hydrothermal synthesis was found to be pH 9 contrary to the isoelectric point of micro-sized CeO2 synthesized by solid state reaction at pH 6.7. IEP was shifted to pH 2.0 as the addition of D-3019 from 0.1 to 1.0 wt%. The surface potential of CeO2 particles synthesized by hydrothermal synthesis was reduced as the addition of B-1001 used as a binder without change of IEP because the absorption of B-1001 polymer on the CeO2 particles shifted the shear plane of CeO2 particles outward away from the surface. This surface potential behavior was well correlated with the dispersion stability of slurry.

• 신재생에너지
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• 제2권4호
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• pp.70-77
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• 2006

The butane decomposition over the catalyst is an attractive method for the hydrogen production. The objective of the work was investigated the catalysis of carbon black in butane decomposition reaction. The Butane decomposition was performed over carbon black catalyst in a range of $500-1100^{\circ}C$. The butane conversion of thermal decomposition and catalytic decomposition were increased with increasing the reaction temperature The butane conversion of the thermal decomposition was higher than the butane conversion of the catalytic decomposition. Hydrogen and methane were mostly observed in the butane decomposition over $1000^{\circ}C$. Especially, the hydrogen yield was steadily increased with raising the reaction temperature, It could be known that the hydrogen yield of the catalytic decomposition was higher than one of the thermal cracking because the hydrogen productivity was improved by the catalyst. The deactivation of the catalyst was not observed in the reactivity test. The surface and crystalline of the fresh and used catalysts were characterized by TEM, BET surface area and XRD analysis, respectively. The fresh carbon black particles had mostly smoothly round-shaped surfaces. In the surface of the carbon black after the reaction, the deposited carbon was formed as the protrusion-shaped carbon and the cone-shaped. The proper peaks of carbon black appeared in XRD analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.976-979
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• 2002

This research presents the new method to fabricate small features through applying chemical mechanical micro machining(C3M) for Al5052 and single crystal silicon. To improve machinability of ductile and brittle material, reacted layer was formed on the surface before micro-drilling process by chemical reaction with $HNO_3$(10wt%) and KOH(10wt%). And then workpieces were machined to compare conventional micro-drilling process with newly suggested one. To evaluate whether or not the machinability was improved by the effect of chemical condition, surface defects such as burr, chipping and crack generation were measured. Finally, it is confirmed that C3M is one of the feasible tools for micro machining with the aid of effect of the chemical reaction.

• 한국표면공학회지
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• 제15권3호
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• pp.146-151
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• 1982

The electrochemical reaction behavior of nickel electrode of the nickel-cadium battery system in potassium hydroxide solution has been studied by cyclic voltammetry, controlled potential electrolysis and X-ray diffraction method. It has been found that the reaction mechanism of positive nickel electrode for charging was assumed to be proten transfer step with a rate controlling diffusion process and char-ging state of positive electrode was amorphous $\beta$-NiOOH.

• 자원리싸이클링
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• 제28권2호
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• pp.23-30
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• 2019

폐자동차 범퍼 파쇄물 재활용을 위하여 색채선별법을 도입하였다. 색채선별법은 기존의 비중, 입도 차이에 의한 선별이 어려운 물질을 색상 차이를 이용한 카메라와 영상 분석기법으로 분리하는 선별법이다. 본 연구에서는 반응표면법 중 BBD (Box-Behnken Design)를 적용하여 실험을 계획하고 최적 조건을 도출하였다. 색채민감도, 피드투입량 및 입자크기의 영향을 분석하였으며, 회귀분석과 통계적인 방법에 기초하여 2차 반응 모델을 획득하였다. $R^2$ 및 p-value는 각각 99.56%, < 0.001로 타당하였으며, 추정된 최적조건은 색채민감도 32%, 피드투입 200 kg/h, 입자크기 33 mm 조건에서 94.1%의 회수율이 나올 것으로 예측하였다. 실제 실험을 통한 회수율은 93.8%로 나타나 해당 모델이 적절함을 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.314-316
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• 2000

Urea is detected as an indicator of renal disease in the human body. For these reasons, many biosensors for urea have been developed based on the enzymatic reaction of urea hydrolysis catalyzed by urease. Potentiometric method is applied reversible reaction system. But urea hydrolysis reaction may not has a reversible reaction mechanism in electrode surface. Therefore we applied to voltammtricmethod to obtain a sensitivity curve. The sensitivity of sensors was 34 ${\mu}$A/decade.