• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.10a
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• pp.2-2
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• 1999

본 연구에서는 액체 로켓용 추진제 분사기로 많이 활용되는 충돌형 분사기중에서 2중 충돌(F-O-O-F)형 분사기에 대한 미립화 특성을 파악하였다. 액적의 크기를 측정하기 위하여 위상/도플러 입자분석기를 사용하였으며, 모의 추진제로 물을 사용하였다. 모의 추진제의 운동량비와 압력 강하량 변화에 따른 2중 충돌(F-O-O-F)형 분사기의 미립화 특성과 크기분포에 대하여 고찰하였다. 분사기 면으로부터 100mm 떨어진 단면에서 산화제/연료의 운동량비가 MR=1.19에서 MR=6.48까지 증가함에 따라 액적크기(SMD)는 감소하였으며, 액적크기(SMD)가 운동량비(MR)에 대하여 SMD= 193.480+15.687MR-5.036M$R^2$+0.415MR$^3$와 같은 관계식에 근사되었다 또한, 연료와 산화제의 압력강하량이 증가할수록 액적크기(SMD)가 감소하였다. 충돌 분무유동장의 액적크기 분포는 Rosin-Rammler 분포함수와 Upper-limit분포함수 모두에 대하여 잘 일치하고 있다. 본 연구의 결과는 액체 로켓용 충돌형 분사기의 초기 설계단계에서 유용하게 사용될 수 있을 것이다.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.2
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• pp.283-291
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• 2000

The purpose of this study was to compare the sedative effect of three routes of administration - intramuscular, intranasal drop-in, intranasal spray - with midazolam. The twenty two uncooperative children from 23 months to 76 months who required at least three dental appointment. Each patient was assigned randomly to receive intramuscular(Group I, 0.15mg/kg), intranasal drop-in(Group II, 0.20mg/kg), intranasal spray(Group III, 0.20mg/kg) administration at each visit. Sleep, crying, movement, and overall behavior response were evaluated, and the sedative effects were evaluated by Houpt's rating scale In order to monitor the sedated patients, pulse rate and peripheral oxygen saturation were measured by pulse oximeter during treatment procedures. The results were as follows 1. Pulse rate and peripheral oxygen saturation were stable through all the treatment procedures, and there were no statistically significant differences among three routes of administration(P>0.05). 2. The effect on sleep was, III, II, I, in order, III group was the most effective through all the treatment procedures, except rubber-dam placement and filling phase (P<0.0001). 3. The effects on crying, movement, overall behavior were II, III, I, in order, II group was the most effective through all treatment procedures(P<0.0001).

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.880-883
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• 2009

석탄가스화복합발전(IGCC) 시스템에서 합성가스 중에 포함된 황화수소($H_2S$)는 후단의 가스 터빈과 같은 장치의 부식을 방지하고, 합성가스를 이용하는 연료전지 등의 연계 공정에서 요구하는 수준에 맞추어 정제되어야 한다. 본 연구에서는 $H_2S$ 정제공정 추가에 따른 IGCC 시스템의 효율저하를 최소화하기 위하여 고온고압에서 사용가능한 탈황제를 분무건조법을 이용하여 제조하고 제조된 탈황제에 대해 물성 및 황 흡수능 시험을 실시하였다. 형상, 내마모도, 평균입자크기, 충진밀도와 함께 제조된 탈황제가 적용되는 유동층 공정에 적합한 강도를 보유하는지 여부를 미국표준시험방법에 의하여 측정하였다. 황 흡수능은 열중량분석기를 반응기로 사용하여 모사 합성 가스 분위기에서 측정하였다. 분무건조 성형된 탈황제의 일부가 구형이 아닌 타원형 또는 도넛 형태를 나타내고 있어 형상 개선을 위한 제조방법 개선이 필요한 것으로 나타났다. 제조된 탈황제는 기공도가 65% 이상으로 macropore가 기공부피의 대부분을, mesopore가 비표면적의 대부분을 제공하고 있었다. 소성온도를 650 $^{\circ}C$에서 750 $^{\circ}C$로 증가시킴에 따라 대체로 강도가 감소하는 경향을 나타내었다. 열중량분석기로 측정된 황 흡수능은 약 10 wt%로 나타났다. 제조된 탈황제 중 일부는 유동층 공정에 적합한 물성을 보유하고 있었으며 반응성 또한 기존에 개발된 탈황제에 버금가는 성능을 나타내어 향후 공정 적용이 가능할 것으로 분석되었다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.1
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• pp.60-66
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• 1995

Abstract The experimental results which is the aerosols behavior and distribution of atomized zinc nitrate ($Zn(NO_3)_2$) solution (0.5 M) by ultrasonic vibrator were in accord with the computer simulations. i.e., most aerosols passing through the reactor (hot zone) moved toward the center of reactor by thermophoresis as the axis of reactor increase. Also, the distribution of aerosols concentration was high at the center of reactor as the axis increase. Among the synthesized ZnO particles, shell-like aggregates of fracture type which could not see at the center of reactor were observed at near the wall of reactor, and the particle size ($ 1.2 {\mu\textrm{m}$) of near the wall was larger than that ($0.9 {\mu\textrm{m}$) of the center.

• Korean journal of applied entomology
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• v.12 no.1
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• pp.23-27
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• 1973

In an effort to find effective inoculation method of Fusarium nivale, this experiment was conducted. The results obtained are summarized as follows: (1) Distilled water-spore suspension of this fungus was inoculated on rice seedling and the result showed that negligible disease symptoms were observed when the inoculated plants were placed in a moist chamber for one day, whereas considerable symptoms were indicated when kept for two days. (2) After giving physical wounds by wind or wooden stick to the rice seedling, distilled water-spore suspenion was sprayed on them and considerable diseased spots were formed. (3) Sufficient disease occurrence was due to the addition of $1\%$ rice leaf extract, glucose, polypeptone, and yeast extract solution to the spore suspension. (4) In distilled water, spore germination was poor, while in nutrient added solution good germination rate as well as anastomosis was found. (5) A new rice variety Tong-il turned out to be more susceptible to Fusarium nivale than Pung-kwang.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1075-1080
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• 2008

Fine-sized $Gd_2O_3:Eu$ phosphor powders were prepared by post-treatment of the precursor powders with hollow shape obtained by spray pyrolysis from the spray solution with citric acid and flux material. Citric acid enabled the synthesis of fine-sized phosphor powders after post-treatment by increasing the hollowness of the precursor powders. The phosphor powders prepared from the spray solution without citric acid had several microns size. Flux materials increased the mean sizes of the phosphor powders. However, flux materials improved the photoluminescence intensities of the phosphor powders under ultraviolet. $Li_2CO_3$ as the flux material was appropriate to prepare the fine-sized $Gd_2O_3:Eu$ phosphor powders with high photoluminescence intensity. The phosphor powders below 3 wt% $Li_2CO_3$ of phosphor had submicron sizes after post-treatment temperatures of $1,050^{\circ}C$ and $1,150^{\circ}C$. The photoluminescence intensity of the phosphor powders post-treated at $1,150^{\circ}C$ was 124% of that of the phosphor powders post-treated at $1,050^{\circ}C$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.447-451
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• 2004

This study was conducted to establish the proper techniques of the recirculating wick hydroponics for safe seed tuber proliferation of potatoes (Solanum tuberosum L. CV. Dejima). To achieve these, several intact tubers (5, 10 and 20 g) and cut seed-pieces (two or four) were treated in wick hydroponic system beds. A polystyrene box (31cm in width, 20cm in height, 51cm in length, and $0.031m^3$ in volume) was placed on a styrofoam hox. Eight wicks $(width\;1.5cm\;{\times}\;length\;40cm) $ were put into each polystyrene hox and the boxes were filled with perlite + peatmoss (1 : 2, v/v) medium. Top fresh weight per plant increased with increasing the tuber size from 10 to 30g/tuber. As the tuber size increases from 10 to 30 g/tuher in case of uncut tuber, the marketable tuber (>5g) production per plant increased from 83.8 to 141.8 g/plant and the marketable tuber (>5g) production per plant of cut tuber was slightly higher than that of uncut treatment. Total tuber yield ranged from 4.16 to $6.56kg/m^2$ and the percentage of seed tubers was greater than $97\%$ for all treatments. These results indicate that seed tuber should be cut to produce large tuber $(\geq10g)$ in the recirculating wick hydroponic system.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.2
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• pp.29-36
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• 2002

Experiments have been performed to investigate the effect of secondary venturi tip angle on flow and spray characteristics in gas turbine combustor with a swirl cup assembly. Three variations of secondary venturi tip angle are made: converging, straight and diverging angles. It is found that the variation of venturi tip angle results in the significant changes of flow and spray characteristics in gas turbine combustors, such as the size and location of recirculation zones. drop size and mass distribution affecting combustion efficiency and NOx emissions. In diverge case, central toroidal recirculation zone(CTRZ) exists near the exit, which is known to be beneficial for flame stability. But in converge case, the finest SMD distribution and uniform mass distribution are found and CTRZ is longer than other cases. Consequently, high combustion efficiency and low pollutant emission are expected in converge case.

• Journal of ILASS-Korea
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• v.3 no.4
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• pp.1-7
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• 1998

The measurement of breakup length of viscous liquid jet in stagnant air was conducted by a 3CCD digital video camera. The nozzle diameters of 4, 6, 8mm with L/d=50 were selected and the dynamic viscosity of viscous liquid made of glycerine and water was in the range of $1.061\times10^{-6}m^2/s$ to $4.935\times10^{-5}m^2/s$. The critical velocity is decreased and the breakup length is increased with the increase of nozzle diameter at the same dynamic viscosity of liquid. At the same nozzle diameter, the breakup length and the critical velocity are both increased with the increase of dynamic viscosity of liquid. It is found in the theoretical analysis that the initial disturbance level is the main cause of occurrance of critical Reynolds number in the stability curve. The comparison of experimental critical Reynolds number and the empirical correlation by Tanasawa and Toyota reveals the relatively good agreement.

• Journal of Life Science
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• v.32 no.4
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• pp.298-302
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• 2022

Sulforaphane is a sulfur-containing substance found in large amounts in cruciferous plants and has been reported in several studies to have anticancer effects. Kale is a representative cruciferous plant known as a superfood and is widely used as an ingredient in various dishes. In this study, in order to investigate a cultivation method for increasing kale's content of sulforaphane, kale was treated with geraniol or methyl jasmonate and water stressed during cultivation using a aeroponic culture system in a fully enclosed plant factory. Geraniol or methyl jasmonate were sprayed on the kale's leaf surface once a day for 2 days, and water deprivation stress was conducted for 3 days after 7 days from first treatment day. No difference in growth between control, geraniol, methyl jasmonate treated groups were observed during cultivation. The study results showed that the kale sulforaphane content increased by 60% in the group treated with geraniol compared to the control group and that the group treated with water deprivation stress in addition to geraniol showed a significant increase of 414%. These results show that kale with an increased content of sulforaphane can be grown and that geraniol can be a good research material for increasing the content of functional substances in plants.