• Magazine of the Korean Society of Agricultural Engineers
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• v.28 no.4
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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%.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.1
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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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• v.42 no.4
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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.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.148-151
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• 2007

We made two injectors that were equal to all design except for existence or nonexistence of swirl chamber of fuel part, because we want to find cooling characteristics at the injector face according to existence or non existence of swirl chamber of fuel part. And we set regenerative cooling channel in injector face for protecting injector face for prolonged combustion time. Two injectors were performed hot firing test, and then we compared cooling characteristics of two injectors. Also we compared O/F ratio effects on cooling characteristics and combustion characteristics.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.2
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• pp.31-36
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• 2001

Teflon-like fluorocarbon thin film was deposited by using difluoromethane$(CH_2F_2$) added with Ar, $O_2$, and $CH_4$ on Si, $SiO_2$, TEOS, and Al substrate. The deposited thin film was characterized by static contact angles for measuring hydrophobicity in various additive gas ratio. temperature, and working pressure. In case of addition with Ar, the static contact angles decreased as additive gas ratio and power increased. But the static contact angles increased as working pressure increased. Specially, super-hydrophobic surface was obtained using the powder-like fluorocarbon thin film above 2 Torr. Added with $O_2$, the static contact angles decreased as the $O_2$ ratio and working pressure increased. And the static contact angles did not change in 100W, but hydrophilic surface was obtained at 200W. In case of addition of CE$_4$, static contact angles dramatically increased in $CH_4/CH_2F_2$ ratio 5. And continuous static contact angles obtained above ratio 5. As compare with previous experiments by thermal evaporation, the fluorocarbon thin film by plasma polymerization was obtained very low hysteresis. This results shows more homogenous surface by plasma polymerization than thermal evaporation process.

• Proceedings of the KIEE Conference
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• 1992.07b
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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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• v.17 no.3
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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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• 2003.12a
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.608-613
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• 2017

We proposed a pyrometallurgical process to achieve gold alloy with an Au content of more than 80wt% from low grade (<35wt%) gold alloys. We performed the heat treatment at a temperature of $1200^{\circ}C$ for 5 hrs using Au35wt%-Ag5wt%-Cu60wt% gold alloys mixed with 1/2 weighed PbO and CaO flux by varying the ratio of PbO/(PbO+CaO) from 0 to 1. We investigated the change in content of the samples with energy dispersive X-ray spectroscopy (EDS) and time of flight secondary ion mass spectrometry (ToF-SIMS). The EDS results showed that the Au content increased from 35.0wt% in the PbO-only sample to 86.7wt% (in the PbO/(PbO+CaO) 1:1 sample), while the other samples achieved more that 84wt%. In addition, the 2/3 flux ratio sample showed the lowest Ag loss into the flux. In the ToF-SIMS results, the PbO only and CaO only fluxes had Au+ peak intensities of 349 and 37, respectively. Although the CaO-only flux might be more favorable considering the loss of Au into the flux, we concluded that the amount of Au lost into the flux could be ignored. Our results imply that that the pyrometallurgical process using a mixed flux is an effective hydrometallurgical process.