• 한국가스학회:학술대회논문집
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• 1998.09a
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• pp.277-280
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• 1998

• Journal of the Korean Chemical Society
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• v.46 no.4
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• pp.397-402
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• 2002

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.689-697
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• 2017

As a fundamental study to apply the new flocculation method using ballast in water treatment process, the optimal conditions for general and ballast coagulant dosage, and pH, which are known to have a significant influence, were derived by response surface methodology. Poly aluminum chloride (PAC) and magnetite ballast were used as a general coagulant and ballast, respectively. Coagulation experiments were performed by jar-tester using the kaolin based synthetic water. The effects of three independent variables (pH, PAC, and ballast) on response variables (turbidity removal rate and average settling velocity of flocs) and the optimum condition of independent variables to induce the optimum flocculation were obtained by 17 experimental conditions designed by Box-Behnken procedure. After performing experiments, the quadratic regression model was derived for each of response variables, and the response surface analysis was conducted to explore the correlation between independent variables and response variables. The $R^2$ values for the turbidity removal rate and the average settling velocity were 0.9909 and 0.8295, respectively. The optimal conditions of independent variables were 7.4 of pH, 38 mg/L of PAC and 1,000 mg/L of ballast. Under these conditions, the turbidity removal rate was more than 97% and the average settling velocity exceeded 35 m/h.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.225.1-225
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• 2003

잣을 이용한 쌀가루즉석죽 제조조건의 최적화와 제조조건에 따른 관능적 특성을 4차원 반응표면분석에 의하여 모니터링 하였다. 죽의 제조에 이용되는 잣은 가루같이 으깬 것을 첨가하는 것이 바람직하였다. 관능적 특성에 의한 잣죽의 점성에 대한 최적조건은 주입액의 양과 잣의 첨가비율이 각각 쌀가루 무게의 15.52배, 16%, 가열조리시간 7.79 분이었으며 이때 $R^2$는 0.9518, 관능평점은 7.45, 임계점은 maximum point였다. 색상에 대한 최적조건은 19.09배, 45%, 2.16분($R^2$=0.7917)이었고 관능평점은 5.44, saddle point였으며, 맛에 대한 최적조건은 12.90배, 22%, 11.40분($R^2$=0.9361), 관능평점은 7.11, maximum point였고, 향에 대한 최적조건은 15.06배, 20%, 4.9분($R^2$=0.8372), 관능평점은 6.16, saddle point였다. 관능적 특성을 모두 만족시켜주는 최적조건은 주입액의 양과 잣의 첨가비율이 각각 쌀가루무게의 16.86배와 15%, 가열조리시간 5.48분이었고 이때 $R^2$는 0.9738, 관능적 평점은 7.69, 임계점은 maximum point였다. 관능적 특성 중 점성은 맛과 전반적기호도에 큰 영향을 주었으며 상관계수는 각각 0.8173($R^2$=0.0001), 0.7878($R^2$=0.0002)이었고 맛은 향과 전반적인 기호도와 밀접한 관계가 있으며 상관계수는 각각 0.5196($R^2$=0.0325)과 0.7004($R^2$=0.0017)이었다.

• Korean Journal of Materials Research
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• v.1 no.2
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• pp.77-85
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• 1991

In this study we have investigated surface morphologies of as-deposited silicon films on the various deposition conditions using LPCVD(Low Pressure Chemical Vapor Deposition) System. The processing conditions such as deposition temperature, pressure and flow rate of $SiH_4$ gas were found to determine the surface morphology. The optimum temperature of maximum effective surface area increased with increasing the deposition pressure and the flow rate of $SiH_4$ gas, These experimental results were also in quite good agreement with the equation derived under the assumption that the maximum effective surface area is obtained on the condition of maximum nucleation rate.

• Journal of Aquaculture
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• v.17 no.2
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• pp.97-102
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• 2004

We examined the effects of stimulants including sunlight and UV-irradiation on the spawning induction and early development of the noble scallop, Chlamys nobilis. The sunlight stimulation resulted in nuch faster spawning induction (100% success within 40 minutes) compared to UV-irradiation (100% success within 70 minutes). Early development of the scallop larva took place between 15$^{\circ}C$ to 3$0^{\circ}C$. The time to reach the early D-shaped stage was 63.5, 31.5, 18.5 and 17.0 hours at 15, 20, 25 and 3$0^{\circ}C$, respectively. The correlations between the water temperature-(WT) regimes and the time (t) required for each developmental stage are as follows. 2 cell stage: 1/t=0.0606WT-0.6194 ($r^2$=0.9791) 8 cell stage: 1/t=0.0304WT-0.3453 ($r^2$=0.9941) Morula: 1/t=0.0100WT-0.1049 ($r^2$=0.9663) Trochophore: 1/t=0.0058WT-0.0618 ($r^2$=0.9848) D-shaped larva: 1/t=0.0030WT-0.0282 ($r^2$=0.9731) These correlations indicated that the biological minimum temperature of the species is around 10.44$^{\circ}C$. The highest survival rate up to D-shaped larva at different water temperature was observed at $25^{\circ}C$.

• Clean Technology
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• v.19 no.1
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• pp.51-58
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• 2013

In this study, kinetics data was obtained for steam reforming reaction of ethane over the nickel catalyst. The variables of steam reforming reaction were reaction temperature, partial pressure of ethane, and mole ratio of steam and ethane. Parameters for the power rate law kinetic model and the Langmuir-Hinshelwood model were obtained from the kinetic data. Also, sizing of steam reforming reactor was performed by using PRO/II simulator. For the steam reforming reaction of ethane, Langmuir-Hinshelwood model determining the reaction rate by the surface reaction was better suited than a simple power rate law kinetic model. On water-gas-shift reaction, power rate law kinetic model was well fitted to the kinetic data. Reactor size can be calculated for production of hydrogen through PRO/II simulation.

• Korean Chemical Engineering Research
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• v.44 no.6
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• pp.650-658
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• 2006

The recycling of TDA from solid waste of TDI plant(TDI-R) by near-critical hydrolysis reaction had been studied by means of a statistical design of experiment. The main and interaction effects of process variables had been defined from the experiments in a batch reactor and the correlation equation with process variables for TDA yield had been obtained from the experiments in a continuous pilot plant. It was confirmed that the effects of reaction temperature, catalyst type and concentration, and the weight ratio of water to TDI-R(WR) on TDA yield were significant. TDA yield decreased with increases in reaction temperature and catalyst concentration, and increased with an increase in WR. As a catalyst, NaOH was more effective than $Na_2CO_3$ for TDA yield. The interaction effects between catalyst concentration and temperature, WR and temperature, catalyst type and reaction time on TDA yield had been defined as significant. Although the effect of catalyst concentration on TDA yield at $300^{\circ}C$ as subcritical water was insignificant, the TDA yield decreased with increasing catalyst concentration at $400^{\circ}C$ as supercritical water. On the other hand, the yield increased with an increase in WR at $300^{\circ}C$ but showed negligible effect with WR at $400^{\circ}C$. The optimization of process variables for TDA yield has been explored with a pilot plant for scale-up. The catalyst concentration and WR were selected as process variables with respect to economic feasibility and efficiency. The effects of process variables on TDA yield had been explored by means of central composite design. The TDA yield increased with an increase in catalyst concentration. It showed maximum value at below 2.5 of WR and then decreased with an increase in WR. However, the ratio at which the TDA yield showed a maximum value increased with increasing catalyst concentration. The correlation equation of a quadratic model with catalyst concentration and WR had been obtained by the regression analysis of experimental results in a pilot plant.

• Journal of the Korean Chemical Society
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• v.37 no.5
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• pp.543-546
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• 1993

• Journal of the Korean Chemical Society
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• v.51 no.4
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• pp.392-397
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• 2007