• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.281-284
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• 2004

본 연구에서는 분무열분해 공정에 의해 폐산용액으로부터 평균입도 100nm 이하의 나노 분말을 제조하였다. 용액 내의 Fe 성분의 농도가 20 g/$\iota$로부터 200 g/$\iota$로 증가됨에 따라 생성된 분말의 입도는 30 nm로부터 60 nm 까지 점점 증가하는 반면 입도분포는 더욱 불규칙하게 나타나고 있었다. 또한 용액 내의 농도 증가에 따라 $NiFe_2O_4$ 상의 생성비율이 현저히 증가하고 있었으며, 입자들의 비표면적은 현저히 감소하였다. 공기압력이 $1 kg/cm^2$까지는 분말의 평균입도는 80$\~$100 nm로 공기압력의 증가에 따라 분말들의 평균입도는 현저한 변화를 나타내지 않았으며, 생성된 상들의 비율의 현저한 변화도 나타나지 않았다. 공기압력이 $3kg/cm^2$로 증가하는 경우에는 평균입도가 약 70 nm로 감소하였으며 $NiFe_2O_4$의 생성비율도 감소하였다.

• Korean Journal of Plant Resources
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• v.9 no.2
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• pp.171-175
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• 1996

The objective of this study is to promote germination for mass cultivation of Adenophora triphylla. After the seed soaking for I day in BA and $GA_3$ solution, seed germination was effectively promoted in the treatment of 500mg/L $GA_3$ and the highest germination rate was 94%.The average germination days were 1.5days earlier than those of non-treated seeds. In a chemicals treatment, seed germination rate was 54% in 1% $KNO_3$ treatment but KOH treatment was no significantly effected. The durations of chilling treatment for breaking of dormancy were longer than 2weeks. The optimal temperature for germination was $25^{\circ}C$. The promotion of seed germination is presumed to be due to the breaking of dormancy by $GA_3$, chilling treatment rather than seed coat maceration by KOH or $KNO_3$ treatments.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.267-274
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• 2009

Breakup and spray formation of pressure-swirl liquid jets injected into a low-speed convective-flow are experimentally investigated. Effects of the cross-flows on the macroscopic and microscopic spray parameters are optically measured in terms of jet Weber number and liquid-to-gas momentum ratio. The liquid stream undergoes Rayleigh jet breakup at lower jet Weber numbers and a liquid sheet isn't formed because of the weak radial velocity in the swirl jet. At higher jet Weber numbers, the macroscopic spray parameter is a very weak function of the momentum ratio but the effect of the convection on the microscopic spray parameter is significant through the secondary breakup with increasing in the liquid-to-gas momentum ratio. The convective-flow promotes bag/plume breakup and the spray formation, and its effect is more distinct at higher momentum ratio.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.11 no.2
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• pp.111-114
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• 1978

The red tide that occurred in Jinhae Bay in the middle of July, 1977 was caused by the microscopic dinoflagellate, Gonyaulax sp. , which is very similar to G. catenella. The cell is round, dorsoventrally flat and transdiameter is about $40\;\mu$. Many cells are chained. Dark brown, band and streak-like patches were formed in the surface water. A great deal of jelly fishes, Chrysaora quinquecirrha and Aurelia aurita, appeared in the red tide area and its surrounding waters. The number of cells was high, being $5.0\times10^5\;cells/\iota$ and among them Gonyaulax sp., predominant species, was $84.8\%$ in maximum. Transparency was less than 1 m in patches. In the surface water, temperature was $25.0^{\circ}C$, chlorinity $17.8%_{\circ}$ and dissolved oxygen $8.11m\iota/\iota\;(180\%)$ during daytime. Red tide stayed for a week. Some oysters were found damaged after the extinction of the red tide but their interrelationship was not found.

• Korean Journal of Plant Resources
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• v.10 no.2
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• pp.122-127
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• 1997

This study was conducted to establish mass propagation system from the tissue culture using immature embroys in Eleutherococus senticosus. Immature embroys from seeds were removed under the microscope and placed on modified SH and WPM medium containing several plant growth regulators. The calli were well formed on media containing 1mg/l of 2,4-D on modified SH medium and 1mg/l of 2,4-D and 3mg/l of TDZ on WPM medium. Shoot regeneration was better on modified SH or WPM medium with combination of high concentration of TDZ and low concentration of 2,4-D. Treatment of 2,4-D alone was better than treatment of TDZ alone in callus induction on modified SH medium but plant regeneration reversed. Treatment of 2.4-D and TDZ combination was better than treatment of 2,4-D alone in callus induction on WPM medium. The results of callus formation and shoot regeneration on WPM media differed to those of SH media. The rate of callus formation was nearly 83% when 2,4-D was added to SH medium on concentration of 1mg/l. The rate of callus formation was nearly 38% when combination treatment of 2,4-D 1mg/l and TDZ 3mg/l was added to WPM medium. Also, plant regeneration differed depending on the mature degree of immature embryo.

• Journal of the korean veterinary medical association
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• v.20 no.4
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• pp.233-238
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• 1984

This experiment was conducted to investigate normal hematologic value of RBC, Hb, PCV, WBC, MCV, MCHC, thrombcyte, differential leukocyte count and diameter of RBC, with 10 males and 10 females of the 182 days- Korean Native Ogolgye designated the number

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.711-716
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• 1993

The mechanism for electrochemical oxidation of natural alkaloid, ${\iota}$-sparteine (SP) was studied in acetonitrile solvent. The cyclic voltammogram of SP shows two irreversible anodic peaks at +0.75 V and +1.45 V vs. Ag/AgCl (0.1M AgNO$_2$ in acetonitrile) electrode. Coulometry reveals that the number of electrons involved in each oxidation peaks is in the range of 1.2∼1.3 respectively. Neutral imine radical was produced by fast deprotonation of SP radical cation formed by oxidation of one nitrogen atom in SP. Two pathways are possible for the reaction of the neutral radical: Due to the disproportionation of the radical, SP and enamine were mainly produced. Also, the 1,2-dehydrosparteinium cation was formed as minor product through the second one electron transfer oxidation of this radical. The (+)-lupanine was produced by treatment of sparteinium cation with potassium hydroxide. We have isolated and confirmed the electrolysis products using IR, GC-MS, UV-Vis, and thin-layer spectroelectrochemical method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.3
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• pp.169-175
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• 1976

A solvent extraction-atomic absorption spectrophotometry for determination of trace amount of cadmium, copper, lead and zinc and a flameless atomic absorption spectrophotometry for mercury in sea water were studied. The optimum pH range for solvent extraction was pH 4-7. A better solvent extraction efficiency was obtained with MIBK solvent than nitrobenzene, benzene, isoamylalcohol, n-buthylacetate. DDTC was more advantageous than APDC as chelating agent. The metals, chelated with DDTC and concentrated into MIBK by solvent extraction with a volume of $1\iota$ of sea water for cadmium, copper and lead, and 200m1 for zinc, were determined simultaneously by atomic absorption spectrophotometry. For mercury determination, 500ml of sea water was digested with permanganate-sulfuric acid and mercury( II ) was reduced by stannous chloride and aerated the solution with air pump until the absorbance reached a constant value. The precisions, in standard deviation, of these methods were 0.058ppb for cadmium, 0.084 ppb for copper, 0.44ppb for lead, 2.49ppb for zinc and 0.08 ppb for mercury. The sensitivities, expressed in $ppb/1\%$ absorption, were 0.058 ppb cadmium, 0. 15 ppb copper, 0.6 ppb lead, 1.2 ppb zinc and 0.01 ppb mercury respectively. No significant adsorption on the wall of polyethylene sample bottle occurred during 30 days of storing by acidification to pH 1.5 with nitric acid except zinc. Poor reproducibility was found for zinc with this method.

• Journal for History of Mathematics
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• v.19 no.1
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• pp.1-16
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• 2006

In 1713, J. Bernoulli first discovered the method which one can produce those formulae for the sum $\sum\limits_{\iota=1}^{n}\;\iota^k$ for any natural numbers k ([5],[6]). In this paper, we investigate for the historical background and motivation of the sums of powers of consecutive integers due to J. Bernoulli. Finally, we introduce and discuss for the subjects which are studying related to these areas in the recent.

• Journal of Power System Engineering
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• v.11 no.2
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• pp.26-31
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• 2007

통신용 전자기기에서 대부분의 열은 증폭기에서 발생한다. 일반적으로 증폭기를 냉각하기 위하여 공랭식을 사용하여 발생하는 많은 열을 냉각하였다. 그러나 전통적인 방법은 고성능 콤팩트화 되어가는 추세에서 발열되는 열을 충분히 냉각하기는 부족하다. 본 논문은 고발열 전자부품 냉각을 위해서 수냉식 방법을 사용하였다. 열전달 효율을 높이기 위하여 냉각판에 직접 냉각수를 흐르게하여 접촉저항을 줄였다. 그리고 냉각판의 유로에 대한 배열과 유량의 비의 효과를 조사하였다. 연구를 수행한 결과, 다음과 같은 결론을 얻을 수 있었다. 냉각수 순환량이 $3{\iota}/min$인 경우, 유로 직경이 8 mm일 때의 냉각 성능이 10 mm일 때보다 우수한 것으로 나타났다. 냉각수 순환량이 $3{\iota}/min$인 경우, 유로 직경이 8 mm일 때의 발열 소자 표면 온도 분포가 더욱 안정적으로 나타났으며, 상하부에 설치된 발열 소자 표면 온도가 더 낮게 나타났다. 동일한 유로 직경의 냉각판에서, 열유속 증가에 따른 냉각수의 전열 성능 증가로 인해 전체 발열량의 증가율보다 발열 소자의 온도 증가율이 낮게 나타났다.