• 한국가스학회지
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• 제15권3호
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• pp.39-46
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• 2011

본 연구에서는 DME와 n-Butane 연료를 사용하여 혼합연료 및 성층화효과가 HCCI 연소 특성에 미치는 영향을 화학반응수치계산을 통해서 알아보고자 한다. 우선, 기존에 완성된 DME와 n-Butane 반응스킴을 이용하여 새로운 화학 반응 모델을 만들고 기존의 DME 화학 반응 모델과 n-Butane 화학 반응 모델과 비교하여 유효성을 확보한다. 나아가, 자발화 특성이 다른 DME와 n-Butane 두 연료의 혼합비 변화에 따른 HCCI 연소 특성을 파악한다. 마지막으로, 혼합 연료를 각각 성층급기 했을 경우에 압력상승률 저감 효과를 파악 한다.

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.299-304
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• 2004

In recent years, silicon carbide has emerged as an important material for MEMS application. In order to fabricate an SiC film based MEMS structure by using chemical etching method, high operating temperature is required due to high chemical stability Therefore, dry etching using plasma is the best solution. SiC film was deposited by thermal CVD at the temperature of 100$0^{\circ}C$ and pressure of 10 torr. SiC was dry etched with a reactive ion etching (RIE) system, using SF$_{6}$/O$_2$ and CF$_4$/O$_2$ gas mixture. Etch rate has been investigated as a function of oxygen concentration in the gas mixture, rf power, working pressure and gas flow rate. Etch rate was measured by surface profiler and FE-SEM. SF$_{6}$/O$_2$ gas mixture showed higher etch rate than CF$_4$/O$_2$ gas mixture. Maximum etch rate appeared at RF Power of 450W. $O_2$ dilute mixtures resulted in an increasing of etch rate up to 40％, and the superior anisotropic cross section was observe

• 한국수소및신에너지학회논문집
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• 제20권5호
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• pp.397-403
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• 2009

The catalysis of carbon black was investigated for the production of hydrogen by the catalytic decomposition of propane-butane mixture gas in this study. The thermal and the catalytic decompositions of hydrocarbons were performed at the temperature range of 500 - $1100^{\circ}C$, respectively. The conversions of hydrocarbons and the mole traction of hydrogen increased with increasing the reaction temperature and the conversion of hydrocarbons in the catalytic decomposition process was approximately liked with that obtained by the thermal decomposition. However, the mole traction of hydrogen produced in the catalytic decomposition process was higher than that obtained from the thermal decomposition. Therefore, it was concluded that the catalysis for the decomposition of hydrocarbons is occurred over carbon black used as catalyst. The mole traction of hydrogen produced by the catalytic decomposition of hydrocarbons also increased with increasing the mole ratio of $C_3H_8/C_4H_{10}$ in propane and butane mixture gas at $700^{\circ}C$. Therefore, it was concluded that the catalytic decomposition of the high propane mixture gas is more effectively for the production of hydrogen.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.868-871
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• 2003

In recent years, silicon carbide has emerged as an important material for MEMS application. In order to fabricate an SiC film based MEMS structure by using chemical etching method, high operating temperature is required due to high chemical stability. Therefore, dry etching using plasma is the best solution. SiC film was deposited by thermal CVD at the temperature of $1000^{\circ}C$ and pressure of 10 torr. SiC was dry etched with a reactive ion etching (RIE) system, using $SF_6/O_2$ and $CF_4/O_2$ gas mixture. Etch rate have been investigated as a function of oxygen concentration in the gas mixture, RF power, and working pressure. Etch rate was measured by surface profiler and FE-SEM. $SF_6/O_2$ gas mixture has been shown high etch rate than $CF_4/O_2$ gas mixture. Maximum etch rate appeared at 450W of RF power. $O_2$ dilute mixtures resulted in an increasing of etch rate up to 40%, and the superior anisotropic cross section was observed.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.2109-2113
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• 2014

Solvent extraction of Fe(III) from chloride solution by using a mixture of D2EHPA (Di-(2-ethylhexyl)-phosphoric acid) and TBP (Tri-butyl phosphate) and the reductive stripping of Fe(III) from the loaded organic were investigated. Quantitative extraction of Fe(III) from the solution (Fe concentration = 90 g/L) was accomplished in two cross-current extraction stages by using the mixture of D2EHPA and TBP. In order to facilitate the stripping efficiency, a reductive stripping method was employed by using $H_2SO_3$ or $Na_2SO_3$ as a reducing agent. The addition of $H_2SO_4$ into reducing agents led to improvement in the stripping efficiency while high concentration acid would suppress it. Both of the mixtures of $H_2SO_4+H_2SO_3$ and $H_2SO_4+Na_2SO_3$ showed good efficiency for the stripping of Fe(III), while the latter was recommended as the stripping solution based on the economics and experimental condition.

• 한국약용작물학회지
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• 제21권3호
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• pp.174-178
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• 2013

Lime-bordeaux mixture has been used to prevent diseases in the field of ginseng. The purpose of this study is to investigate the efficacy of lime-bordeaux depending on the concentration and treatment time on major diseases of ginseng such as Alternaria blight and anthracnose, and to evaluate the root growth of ginseng. Lime-bordeaux caused damage on leaf when it was sprayed on ginseng between April and early May. No difference was found in root growth by spraying lime-bordeaux mixture between ratio 4-4 and 8-8 ratio in concentration. Plot of 6-6 raito and 8-8 ratio appeared to be similar efficacy compared to that of practical chemical control. However, the plot of 4-4 ratio showed lower than that of chemical control.

• Applied Biological Chemistry
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• 제35권4호
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• pp.286-293
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• 1992

개량식과 재래식 된장의 기호와 향기의 단점을 개선하고 장점을 유지하기 위하여 재래식, 개량식 그리고 납두를 혼합 제조한 된장의 이화학적 변화와 관능검사에 의한 적정배합 비율과 숙성정도를 검토하였다. pH는 개량식 메주에 납두의 배합량이 높을수록 증가하였으며 재래식 메주의 배합에서는 감소하였다. 재래식 메주에서의 질소화합물 함량은 개량식에서 보다 3배 높았으며 숙성도 빨랐다. 갈색색소의 변화는 초기의 값에 따르며 재래식이 높았다. 개량식과 재래식 그리고 납두를 혼합한 구가 관능적 평가가 높았으며 그 비율은 개량식, 재량식 그리고 남두의 비가 48 : 48 : 5의 비율이었다.

• 한국세라믹학회지
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• 제42권5호
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• pp.338-345
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• 2005

To prepare the complex gel of flux and pseudo-boehmite used in precursor of the flaky ${\alpha}-A1_2O_3$ crystal, aqueous solution of the mixture of sodium carbonate and sodium phosphate was added with stirring in aqueous solution of the mixture of sodium sulfate, potassium sulfate and titanium sulfate. The complex gel was dried at $110^{\circ}C$ and was crystallized above $1,050^{\circ}C$, and then the effect of the amount of titanium sulfate on size, morphology, thickness and crystal size distribution of the flaky ${\alpha}-A1_2O_3$ crystal was investigated. Addition of titanium sulfate was prevented the aggregation and generation of twin crystal, and had an effect on the crystal size and the thickness during crystal growth. When the amount of titanium sulfate was more than 6 g, particle size was decreased but was free from crystal twining and aggregation. On the other hand, when the amount of titanium sulfate was lower than 6 g, crystal size was increased but crystal twinning and aggregation were noticed.

• Journal of Ginseng Research
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• 제14권3호
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• pp.421-426
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• 1990

Field and laboratory works were conducted to Investigate the life history, ginseng damage and chemical control effect of the field slug, Deroceras varians A. Adams. D. varians laid eggs from April to June, but a small number of eggs were also found from July to September in the field. Most young slugs grew through the slimmer months to maturity by October. overwintered beneath the moist soil surface, and began feeding and egg-laying in the following April. indicating that D varians have a life cycle in a year. Damage of ginseng plants by D. varina occurred mainly from late April to mid May in the 3rd to 5th year ginseng fields with rice-straw mulching. It seems that this damage is caused by the adults in oviposition periods and related to rice-straw mulching of ginseng fields. In the experiment, ethoprop 5% granule and metaldehyde 6% bait showed relatively high effectiveness in the control of D. varians adults. Bordeaux mixture was more effective when the chemical was sprayed after infestation of the slug than before the infestation and when the 6-12 mixture was used.

• Bulletin of the Korean Chemical Society
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• 제28권3호
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• pp.439-442
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• 2007

A solid state Hg(Au)/HgO reference electrode was prepared utilizing gold amalgam solid particles. Solid fine powder of the gold amalgam was prepared by chemical reduction of Au(III) with NaBH4 followed by reduction of Hg(II) in the presence of gold fine particles. The solid content in the suspension of the gold amalgam particles and fine mercury oxide particles in DMF containing PVC was precipitated by the addition of a large amount of water to give solid Hg(Au)/HgO/PVC mixture. After drying, the mixture was pressure-molded to a physically stable Hg(Au)/HgO composite reference electrode material. The electrochemical characteristics of the electrode as a reference electrode were very similar to an ordinary Hg/HgO reference electrode. The electrode material can be molded and fabricated in any desired shape and size. The surface can be renewed by a simple polishing process whenever contaminated or deactivated. The applicability of the electrode in the electrochemical detection of carbohydrates after anion exchange separation was evaluated.