• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.668-678
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• 2017

In this study, the hydrological and meteorological drought index with precipitation as a major factor were calculated, and various analyses of hydrological drought were conducted. The Modified Surface Water Supply Index (MSWSI) was applied to the hydrological drought index and Standardize Precipitation Index (SPI) was used to estimate the meteorological drought index. The target area for the estimation is the dam area among MSWSI categories. The 4001 basin with 43 years data from 1975 to 2017 was analyzed for the drought occurrence status and time series plotted with the monthly SPI and MSWSI. For the dam watershed based on the precipitation that has the role of a water supply in the hydrological cycle, correlation analysis of precipitation, dam inflow, and stream flow was performed by the monthly and moving average (2~9 months), and the correlation between meteorological and hydrological index by monthly and moving average (3, 6 months) was then calculated. The result of multifaced analysis of the hydrological drought index and meteorological drought index is believed to be useful in developing water policy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.558-567
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• 2020

This study examined the defect characteristics of fuel flow proportioner-mounted structures to analyze the causes of structural defects during aircraft operation. System vibrations and single component vibrations that occur during aircraft operations are usually the cause of structural defects. The fuel flow proportioner causes a defect in the support structure due to the vibration caused by the pressure change caused by the sudden increase in the flow rate. Defects in the support structure of the fuel flow proportioner are not correlated directly with the cracking of the maneuver, and flight time according to aircraft operation analysis is related to the use of A/B. The structural reinforcement configuration was confirmed through static and life analysis of the cracks of the bracket mounted under the fuel flow proportioner for improvement of the defect. An analysis of the reinforcement revealed a minimum structural strength of +0.15. Structural life analysis confirmed that the stress acted on the site under 15Ksi. The fatigue life was confirmed to be more than 7,700 Cycles.

• Korean Journal of Environmental Agriculture
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• v.3 no.2
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• pp.1-8
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• 1984

The present study was performed to elucidate pesticide residues in paddy rice applied with different application schedules and frequencies of pesticide formulations. Pungsanbyeo($Japonica{\times}Indica hybrid$) of rice(Oryza sativa L.) was chosen as target crop. Isoprothiolane(diisopropyl-l,3-dithiolan-2-ylidene malonate) 40EC (emulsifiable concentrates), 12G (granular), and chlorpyriphosmethyl [0,0-dimethyl 0-(3,5,6-trichloro-2-pyridyl) phosphorothioate] 25EC, 3G were selected as pesticide formulations. The closer the isoprothiolane EC application to harvest, the higher the residues in rice straw retained at harvest; however the G application on 30 days before harvest resulted in highest residue. Chlorpyriphosmethyl residues were higher as it was applied nearby to harvest. Degradation rate of chlorpyriphos-methyl in husked rice was quite similar to in rice straw, on the other hand isoprothiolane in the rice was more stable than that in rice straw. Translocated amount of applied G formulation to husked rice was meager irrespective to the chemicals. Percent reduction of isoprothiolane residues in husked rice by polishing was not related to application frequencies but to application date before harvest. Residual portions in rice straw, husked rice and polished rice of total input amount during rice cultivation were ranged from 0.19% to 0.99%, 0.01% to 0.48%, and 0.15%, respectively.

• Microbiology and Biotechnology Letters
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• v.26 no.1
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• pp.1-6
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• 1998

The characteristics of $CO_2$ fixation by Chlorella HA-1 cultured in bubble columns were studied to achieve high photosynthetic rates per basal area. The influence of experimental conditions such as the diameter of a bubble column and gas flow rate, on photosynthesis of Chlorella HA-1 was investigated. The maximum productivity and the overall $CO_2$ fixation rate obtained in a 0.15 L bubble column was 1.09 g dry biomassa-day and 1048 g CO$_2/\m^2$-day, respectively. Light limitation has been observed in the bubble columns having a diameter larger than 3.5 cm.. As the reactor volume increased, the decrease of the $CO_2$ fixation rate was remarkable. High gas flow rate was helpful to mitigate the light limitation problem.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.73-82
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• 2016

The energy consumption efficiency in a variety of operational test mode was considered for domestic gas boiler below 70 kW. The energy efficiency test carried out in the experimental conditions similar to the actual operation status was analyzed and compared with the current Korean efficiency test method. Four types of test modes for each boiler(Non-condensing and condensing boiler) were carried out in the condition of laboratory mode(full load, steady state) and actual operating mode. Futhermore divided into two operational status for each of these, it was applied by maximum gas consumption and consumer sales conditions. Test equipment has the function referred to gas boiler standards, such as KS or European standard EN. The equipment should be continuously measured and record the measuring factors which are the flow volume of gas and water, laboratory temperature, water flow volume for heating, return water volume after heating and quantity of the exhaust gases(CO, NO, $NO_2$). The experimental results were found that non-condensing boiler efficiency of laboratory mode is about 10% higher than that of actual mode. In case of condensing boiler, the efficiency of laboratory condition is about 20% higher than that of the actual using conditions. I suggest that the government will gradually take the efficiency test method considering the actual conditions.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.605-613
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• 1992

NCO-terminated prepolymers were synthesized by reacting carbonate-type polyol(PTMCG)($M_w=1,000$ and 2,000) with MDI and N-methyldiethanolamine, as a chain extender. Carbonate-type polyurethane containg zwitterionic group was prepared by reacting the prepolymer with 1,3-propane sultone. From the IR and NMR spectra of model reactions, it was known that the ionization occurred under the same condition. The structure of zwitterionic carbonate-type polyurethane(ZPU) therefore could be confirmed from the model reactions. Glass transition temperature(Tg) ranged between $-15{\sim}-30^{\circ}C$ from the thermal data. Tg was between $-15{\sim}-18^{\circ}C$ for a series of ZPU10 samples and between $-25{\sim}-26^{\circ}C$ for a series of ZPU20 polymers. Tensile strength increased with mole ratio of ionic content. On the contrary, elongation was rather dropped with mole ratio of ionic content. ZPU10-30 having better tensile strength and less elongation was selected as a membrane for the concentration of ethanol aqueous solution through pervaporation. To obtain the better selectivity, it was crosslinked with HMDI. In the swelling test, it showed the higher swelling degree at around 50wt% ethanol concentration due to the plastization effect of ethanol. To optimize the separation capacity, two operating factors-feed concentration and temperature-were considered. The overall separation capacity was as follows : separation factor, 2~83.2 ; the flux, $25.4{\sim}58.8g/m^2hr$.

• Proceedings of the Korean Vacuum Society Conference
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• 1998.02a
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• pp.55.2-55
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• 1998

다견정 심리판-거l르마늄(JXlly-SiGe)은 TFT(thin-film transistor)와 갇븐 소자 응용에 있어서 중요한 불칠이다 .. LPCVD (low pressure chemical vapor deposition) 방법으로 비정칠 SiGc (a-SiGe) 박막올 증 착시키고 고상결정화(SPC: solid-phase crystallization)시켜 poly-SiGc옹 얻는 것은 잘 알려져 있다. 그러 나 그러나 PF'||'&'||'pound;VD-SPC 방법올 이용한 poly-SiGc의 제조에 대해서는 아직 두드러지게 연구된 바 없다. 우리단 PF'||'&'||'pound;VD 방법으로 a-SiGc 박막올 증착시키고 고상캘정화시켜 poly-SiGc올 얻었 R며, :~ 결정성, G Gc 농도, 결정핍의 평끌 크기 눔올 XRD (x-ray diffraction) 방법으호 조사하였다. 특히 pr'||'&'||'pound;VD 증착시 가판온도,Gc 함유량 등이 고상화에 미치는 영향에 대해서 조사하였다. P PECVD 장치는 터보펌프콸 사용하여 71저진공이 2xlOlongleftarrow5 Torr에 이르렀다. 가판윤 SiOOO) 웨이퍼륜 사용하고 기판 온도는 약 150- 35()"C 사이에서 변화되었다. 증착가스는 SiH4, GcH4, 112 등흘 썼다. 증착 압력과 r.f 전력용 각각 O.25ToIT와 3W로 일정하게 하였다 .. Gc 함유량(x)은 x x=O.O-O.5 사이에서 변화되었다 .. PECVD모 증착된 SiGc 박막들은 고상결정화를 위해 $\theta$X)"(:: Nz 분위기에서 24시간동안, 혹은 5OO'C에서 4열간 가열되었다. 고상결정화 후 poly-SiGc 박막은 SiGc(Ill), (220), (311) XRD 피크들올 보여주었으며, 각 피 크들은 poly-Si에 비하여 왼쪽으로 Bragg 각이 이동되었고, Vegard’slaw에 의해서 x의 값올 확 인할 수 있었다. 이것온 RBS 결과와 열치하였다. 약 150-350'C 사이에서 변화된 기판온도의 범위 에서 증착온도가 낮올수콕 견정립의 크기는 대체로 증가하는 것으로 나타났다 .. XHD로 추정된 형 균 결정립의 크기는 최대 약 3$\alpha$1m 정도였다. 또한 같끈 샘플뜰에 대해서 기판온도가 낮올수록 증착속도가 증가함옴 확인하였다 .. Gc 함유량이 x=O.1에서 x=O.5로 증가함에 따라서도 결정립의 크기와 SiGc 증착속도는 증가하는 것으로 나타났다 .. Hwang [1] , Kim[2] 둥의 연구자들은 Gc 함유 량이 증가함에 따라 결정 립 크기가 캄소하는 것올 보고하였으냐, Tsai [3] 둥은 반대의 결과플 보 고하고 Ge 힘유량의 증가시 결정립 크기의 증가에 대해 Gc의 Si보다 낮은 융점 (melting point) 올 강조한 바 있다. 결정립 크기의 증가는 대체로 SiGe 중착속도의 증가와도 관련이 있음올 볼 때, poly-SiGc의 경우에도 polv-Si의 고상화에서와 같이 증착속도가 빠를수록 최종적언 결정럽의 크기가 커지는 것으로 이해될 수도 있다 .. PECVD 증착시 증착속도의 증가는 증착된 박딱에서의 무켈서도를 증 가시킬 수 있음올 고려하면, 이라한 결파플온 p이y-SiGc의 고상결정화에서도 ploy-Si의 고상결정 화에서와 마찬가지로 초기 박막에서의 구조직 무절서도가 클수록, 고상결정화 후 결정 립의 크기 가 커칠 수 있음올 보여준다고 생각휠 수 있다,

• Korean Journal of Food Science and Technology
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• v.13 no.2
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• pp.153-159
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• 1981

A study was carried out to determine the optimal sterilization conditions of cooked rice packed in retort pouch and processed in a steam-air system retort. The cooked rice packed in retort pouch in various thickness (15, 20 and 25 mm) was processed at various heating temperature (110, 115 and $120^{\circ}C$) with $F_0$-value 6.0. In order to evaluate quality change during the thermal prosessing, C-values, based on z-value $33^{\circ}C$ and $F_0$ value 6.0, were also calculated at surface, center and mass average temperatures. Subsequent storage study revealed that the cooked rice packed in 15 mm thickness and processed at $120^{\circ}C$ with$F_0$-value 6.0 could be held without any spoilage and color change, when stored for 6 months at $38{\pm}1^{\circ}C$ under saturation humidity.

• Journal of Korea Water Resources Association
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• v.40 no.3
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• pp.265-276
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• 2007

An understanding of the hydraulic characteristics in the compound channel with vegetation is important in designing stream restorations or managing the floodplain. A laboratory flume of 16 m long and 0.8 m wide was used for analysis of the hydraulic characteristics in the single section channel and the compound channel with artificial vegetation. Slope of experimental channel is 0.5 %. Discharges are ranged from $0.2\;m^3/s\;to\;$0.4\;m^3/s$. The experiments were done by changing water depth ratio, vegetation density and vegetation location. When water depth ratio in the single section channel with vegetation increase up to 3.5, the results showed that the increment of water depth due to vegetation may be ignored in practice. The maximum increment of water depth was measured up to 6 % in the compound channel with vegetation and the range of velocities increment in the low flow channel was from 25 % to 85 % compared with section average velocities. As the vegetation densities increase and water depth ratios decrease, the velocity of the low flow channel increased. The range of roughness coefficients in the vegetated reaches were estimated from 0.055 to 0.14 in the single section channel and from 0.063 to 0.085 in the compound channel using HEC-RAS and RMA-2 model.

• Membrane Journal
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• v.23 no.1
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• pp.1-11
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• 2013

Poly(ether imide) (PEI)-poly(dimethylsioxane) (PDMS) composite membranes and their modules were prepared, which are capable of selective $CO_2$ separation from the mixture gas. The gas flow rate, concentration, recovery ratio of $H_2$ and removal ratio of $CO_2$ outflowing by stage-cut were characterized at $25^{\circ}C$ and the constant pressure. In addition, to increase the recovery ratio of $H_2$, one stage, two stage series connection, and three stages series + parallel connection tests were carried out. When the stage-cut was 0.32 for the three stages connection operation, the concentration $H_2$ of the produced gas and the recovery ratio of $H_2$ was 97% and 85%, respectively. And also the removal ratio of $CO_2$ was 90% was obtained and the recycled gas concentration was similar with that of the feed gases.