• 한국농공학회지
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• 제28권4호
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• pp.41-48
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• 1986

This study was fulfilled by the weighing lysimeter method at the experimental farm of KonKuk University from April to June of 1986 to investgate the amount of evapotranspiration ( ET-lettuec )by the growing periods, evapotranspiration ratio, amount of watering per one time, days of intermission and soil moisture extraction pattern of the crisphead lettuce cultivated in the clay loam soil by different watering points of pFl.7, pF2.O, pF2.7. The results obtained are summar ized as follows : 1.The total evapotranspiration(ETlettuce) of the pFl.7 treatment plot was 358,9mm., 314.9mm in the pF2.O plot and 281.8mm in the pF2.7 plot, therefore the total ETlettuec increased with the difference of 33mm-44mm by the decrease of watering point. 2.The daily maximum ETlettuce by the watering points was 7.66mm, 6:54mm, 5.98mm, respectively in the last ten days of May, and the mean daily ETlettuce during the growing season by the watering points of pFl.7, pF2.O and pF2.7 was 5.44mm(384.5g), 4.77mm(337.2g) and 4.27mm(301.8g), respectively. 3.The evapotranspiration ratio showed maximum value in the middle of May which was the beginning of mid-season stage, and the mean evapotranspiration ratio during the total growing period was 1A7, 1.29, 1.15 by the watering points. 4.The days of watering intermission by the watering points of pFl.7, pF2.O and pF2.7 was 1.0day, 2.9days and 12.Sdays, respectively. 5.The yield of the crisphead lettuce by the watering treatments showed very high significance, and the pF2.O was confirmed as a optimum watering point. 6.The soil moisture extraction pattern(SMEP) of the pF2.0 treatment plot in the initial stage was 85.6% in the 1st and 2nd soil layer and 14.4% in the 3rd and 4th layer, and in the midseason stage, the moisture extraction proportion of the under layer accounted for 34.7%which showed that the root elongated to the lowest soil layer, and there was no difference of the SMEP between the mid-season and late-season stage. 7.The correlation coefficient between the ETlettuce and yield of lettuce by the three watering points was.739, which showed the significance of 5%.

• 한국토양비료학회지
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• 제49권5호
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• pp.577-583
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• 2016

Small-sized persimmons produced by high crop load are better accepted in the export markets. However, maintaining high crop load frequently results in weakness of tree vigor, deterioration of fruit quality, and increase of the risks for alternate bearing. This experiment was conducted to determine the combined effects of fertilization rate and leaf-fruit (L/F) ratio on container-grown 3-year-old 'Fuyu' persimmon trees. Application of 3.6-g N, 2.1-g $P_2O_5$, 2.7-g $K_2O$, 2.7-g CaO, and 0.6-g MgO was for the control fertilization rate (CF) and that of a 3-fold CF was for the high fertilization rate (HF). Commercial fertilizers were surface-applied to a container on July 6, July 17, and August 10 in three equal aliquots. Single tree for each fertilization rate was assigned for 12 L/F ratios (5, 6.3, 7.7, 9, 10.4, 13, 15.5, 18, 21, 24, 27, and 33) mostly by fruit thinning or rarely by defoliation on July 1. HF did not affect the yield, weight and soluble solids of the fruits but decreased skin color. As L/F ratio increased, yield decreased but average weight, skin color, and soluble solids of fruits increased. With HF, N and K concentrations in leaves, fruits, and shoots increased to some extent but soluble sugars in dormant shoots decreased. Many shoots were cold-injured with low L/F ratio especially at the HF. HF did not increase number of flower buds the next spring either on a shoot or on a tree basis but increased shoot length, compared with the CF. Increasing L/F ratio markedly increased number of flower buds and shoot growth the following year at both fertilization rates. Therefore, an appropriate combination of fertilization rate and L/F ratio should be necessary to maintain stable fruit production and tree vigor at high crop load.

• 한국전기전자재료학회논문지
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• 제13권1호
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• pp.6-12
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• 2000

In this study, molybdenum thin films were etched with Cl\ulcorner/(Cl\ulcorner+SF\ulcorner) gas mixing ratio in an magneti-cally enhanced reactive ion etching(MERIE) by the etching parameters such as rf power of 250 watts, chamber pressure of 100 mTorr and B-field of 30 gauss. The etch rate was 150nm/min under Cl\ulcorner/(Cl\ulcorner+SF\ulcorner) gas mixing ratio of 0.25. At this time, the selectivity of Mo to SiO\ulcorner, photoresist were respectively 0.94, 0.05. The surface reaction of the etched Mo thin films was investigated with X-ray photoelectron spectroscopy(XPS). It was analyzed that Mo peaks was mainly observed in Mo-O bonds formed MoO\ulcorner compounds and F was detected in Mo-F and O-F bonds. Cl peaks were detected by the peak of Cl 2p\ulcorner in Cl-Mo bonds of MoCl\ulcorner or MoO\ulcornerCl\ulcorner formulas. Almost all of both Cl and S atoms had been com-bined with Mo, respectively.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.174-182
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• 2018

Background: In this study, we observed their growth and physiological responses using a variety of duty ratio under the mixed light using red, blue, and white lights. The red+blue mixed light was treated with 95%, 90%, 85%, 80%, and 75% duty ratios and red+blue+white mixed light with 85% and 70% duty ratios. We examined the width and length of leaves, total number of leaves, and number of shoots to examine their growth responses. The physiological responses were studied by measuring their photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, chlorophyll content, and fluorescence ($F_o$, $F_m$, and $F_v/F_m$). Results: We found that lower duty ratio caused the length and width of the leaves to grow longer under red+blue mixed light but that it did not cause any difference in the red+blue+white mixed light condition. In addition, there was no difference in the number of leaves and shoots among all treatments. In the red+blue mixed light condition, the photosynthetic rate was no difference, but both transpiration rate and stomatal conductance were the highest at 95% duty ratio than in other ratios. Water use efficiency pattern was similar to that of photosynthetic rate; water use efficiency was no difference. Chlorophyll content was the highest at 95% duty ratios, and it was the least at 90%, 85%, and 75% duty ratio. $F_o$ and $F_m$ values were relatively high at 85% and 80% duty ratio and low at 90% duty ratio while $F_v/F_m$ showed no difference. Conclusions: Under the red+blue+white mixed light, all physiological items showed no difference between 70 and 85% treatments. But, photosynthetic rate, water use efficiency, chlorophyll content, and $F_v/F_m$ were relatively greater in the red+blue+white mixed light than in the red+blue mixed light. Therefore, red+blue+white mixed light treated with 70% duty ratio could lessen the environmental stress and save more power when cultivating Silene capitata in a plant factory.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.148-151
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• 2007

동축 스월 인젝터 중에서 연료 인젝터의 스월 챔버 유무에 따른 인젝터 페이스의 냉각 특성을 알아보기 위해서 연료의 스월 챔버의 유무 조건만 다르고 모든 설계 조건이 같은 두 개의 인젝터를 만들었으며, 장시간 연소가 가능하도록 물을 이용한 재생 냉각 채널을 인젝터 페이스에 설치하였다. 두 개의 인젝터를 이용하여 연소 실험을 수행한 후 인젝터 페이스의 냉각 특성을 비교하였고, O/F ratio 2.0일 때와 O/F ratio 1.7일 때의 연소 특성 및 인젝터 페이스의 냉각 특성을 살펴보았다.

• 마이크로전자및패키징학회지
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• 제8권2호
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• pp.31-36
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• 2001

Plasma Polymerization를 이용하여 Teflon-like 불화 유기 박막을 Si, $SiO_2$, Al, TEOS 위에 증착하였다. Difluoromethane $(CH_2F_2$)에 Ar, $O_2$, 그리고 $CH_4$를 첨가하여 첨가 가스에 따른 불화 유기 박막의 특성을 평가하였다. 각각의 첨가가스에 대하여 압력, 온도, 그리고 첨가가스의 비율을 변화시켜 박막을 증착하여 정접촉각 통한 표면의 친수성 (hydrophilicity)과 소수성(hydrophobicity) 정도를 관찰하였다. Ar을 첨가한 경우 Ar 첨가량과 power의 증가에 따라 정접촉각의 감소를 관찰하였다. 그러나 증착압력이 증가함에 따라 정접촉각이 증가하였다. Ar 첨가시 2 Torr이상의 증착압력에서 분말형태의 초소수성 불화 유기박막을 얻을 수 있었다. $O_2$를 첨가한 경우, $O_2$의 첨가량과 증착압력이 증가함에 따라 정접촉각은 감소하였다. 약 100W까지의 power에서는 정접촉각은 일정하였지만 power의 증가에 따라 정접촉각은 감소하여 200W에서는 천수성표면을 얻을 수 있었다. $CH_4$를 첨가하여 불화유기박막을 증착하였을 경우 $CH_4/CH_2F_2$비율이 5까지 급격한 증가를 나타내었고, 비율이 5이상인 경우에서는 일정한 정접촉각을 나타내었다. 화학기상증착에 의해 제조된 박막보다 plasma polymerization으로 제작된 불화유기박막이 히스테리시스(hysteresis)가 낮은 불화유기박막을 형성하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.847-849
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• 1992

Fluorine-doped ($SnO_2$:F) thin films obtained by pyrosol deposition method have been exposed to R.F. excited pure hydrogen plasma under the following conditions; substrate temperature of 200$^{\circ}C$, $H_2$ pressure of 1 Torr, R.F. input power of 50 mW/$\textrm{cm}^{2}$, $H_2$ flow rate of 30cc/min and exposure time of 15-600 seconds. It is found that the sheet resistance of the films remains unchanged or rather slightly reduces for initial exposure time of 30-60 seconds, but increases sharply with further increasing the exposure time. The optical transmittance of $SnO_2$:F films slows a rapid fall with increasing exposure time except for a film obtained with a solution having $CH_3OH/H_2O$ mol ratio of 2.65, its degradations at the exposure time of 30-60 seconds are about 7-15%. In addition, the exposure of the films to hydrogen plasma atmosphere leads to remarkable changes in the microstructure and chemical composition, which should be attributed to the reduction of $SnO_2$ to SnO and to elemental Sn.

• Corrosion Science and Technology
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• 제17권3호
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• pp.138-145
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• 2018

The aim of this work is the attainment of the $TiO_2-nanotube$ photocatalytic-growth condition using anodization, whereby the $NH_4F-H_2O$ weight ratio is appropriately controlled. We fabricated the $TiO_2$ nanotubes using a two-step anodization (first step is 1 hr; second step is 30 hr) under the ambient pressure and the room temperature at 60 V in ethylene-glycol solutions to investigate the effects of the $NH_4F$(0.1,0.3,0.5wt%) and $H_2O$(1-3wt%) on the $TiO_2-nanotube$ geometry and the photocatalytic efficiency. Further, the decomposition efficiency of the methylene blue on the $TiO_2$ nanotubes by the UN radiation depended on the geometrical change of the nanotube geometry, indicating the proportionality of the decomposition efficiency to the surface area that was affected by the $NH_4F$ and $H_2O$ concentrations. As the $NH_4F$ weight was increased, the surface area initially decreased but slightly increased later, and the length consistently increased. As the $H_2O$ weight was increased, the surface area and length initially increased, but later decreased with the 3 wt% $H_2O$.

• 한국연소학회:학술대회논문집
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• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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• pp.125-130
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• 2003

본 논문에서는 액체로켓엔진에서 터보펌프의 160kW급 터빈을 구동하고, 액체산소와 케로신을 추진제로 사용하는 가스발생기의 설계점 연소성능시험 결과에 대해 논의하였다. 충돌형 F-O-F 인젝터, 물냉각 채널을 가진 연소실, torch ignitor, turbulence ring 그리고 측정 링을 갖는 가스발생기에 대해 기술하였고, 점화, 연소, 종료 등의 시험 cyclogram에 대해 언급하였다. 설계점에서의 연소시험 및 turbulence ring 장착여부, 연소실 길이 변화에 따른 연소시험의 결과들에 대해 기술하였다. 연소시험 결과 가스발생기는 설계점에서 안정된 작동성을 보여주었고, 연소압력 및 온도 등의 성능이 예측치에 근접하는 결과를 보여 주었다. Turbulence ring은 출구에서의 가스온도를 균일하게 분포시켜 효과적인 혼합 장치임을 보여 주었고, 4-6msec 정도에서의 잔류시간에서는 연소효율의 차이가 크지 않음을 알 수 있었다. 가스발생기 출구에서의 온도는 공급되는 추진제의 O/F ratio에 따라 매우 민감하게 반응함을 알 수 있었다.

• 한국산학기술학회논문지
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• 제18권4호
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• pp.608-613
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• 2017

본 연구에서는 저품위인 35wt% 금합금에 대해 80.0wt% 이상의 Au를 얻기 위한 건식 정련 공정을 제안하였다. Au35wt%-Ag5wt%-Cu60wt%의 조성을 가진 금합금에 대해 PbO/(PbO+CaO)의 혼합비를 각각 0~1로 변화시키고 플럭스/금합금의 무게비는 1/2로 하여 $1200^{\circ}C$-5시간의 열처리를 진행하였다. 이때 공정 전, 후 시료의 조성 변화는 energy dispersive X-ray spectroscopy(EDS)로 확인하고, 공정이 완료된 후 분리된 플럭스 금속 원소 성분은 time of flight secondary ion mass spectromerty(ToF-SIMS)로 확인하였다. EDS분석 결과 플럭스의 비율이 1(PbO 단일)인 경우 Au의 함량이 35.0wt%에서 86.7wt%로 가장 크게 향상되었고, 다른 플럭스 조성의 경우도 84wt% 이상으로 정련이 가능하였다. 또한 2/3 혼합비의 플럭스에서 Ag가 플럭스부로 빠져나가는 손실이 가장 적었다. 플럭스부의 ToF-SIMS 분석 결과 플럭스의 비율이 1, 0 일 때 $Au^+$의 특성 피크의 강도가 각각 349, 37로 측정되었다. Au의 손실을 고려하였을 때 CaO 단일 플럭스의 사용이 더 유리할 수 있었으나, 이 정도의 신호강도는 무시할 수 있는 정도로 판단되었다. 따라서 혼합플럭스를 이용한 건식 열처리를 통해 효과적인 금의 정련이 가능하여 경제적인 습식제련의 전처리 공정으로 사용될 수 있음을 확인하였다.