• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.2
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• pp.166-174
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• 2018

Potato(Solanum tuberosum L.) is one of the major food crop in the world following rice, wheat, and maize. It is thus important to project yield predict of potato under climate change conditions for assessment of food security. A crop growth modelling is widely used to simulate crop growth condition and total yield of various crops under a given climate condition. The decision support system for agrotechnology transfer (DSSAT) cropping system model, which was developed by U.S. which package integrating several models of 27 different crops, have been used to project crop yield for the impact assessment of climate change on crop production. In this study, we simulated potato yield using RCP 8.5 climate change scenario data, as inputs to the DSSAT model in five regions of Korea. The genetic coefficients of potato cultivar for 'superior', which is one of the most widely cultivated potato variety in Korea were determined. The GenCalc program, which is a submodule of the DSSAT package, was used to determine the genetic coefficients for the superior cultivar. The values of genetic coefficients were validated using results of 39 experiments performed over seven years in five regions. As a case study, the potato yield was projected that total yields of potato across five regions would increase by 26% in 2050s but decrease by 17% in 2090s, compared with 2010s. These results suggested that the needs for cultivation and irrigation technologies would be considerably large for planning and implementation of climate change adaptation for potato production in Korea.

• Korean Journal of Remote Sensing
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• v.32 no.5
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• pp.435-452
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• 2016

Land Surface Temperature (LST) has been operationally retrieved from the Communication, Ocean, and Meteorological Satellite (COMS) data by the spilt-window method (CSW_v2.0) developed by Cho et al. (2015). Although the CSW_v2.0 retrieved the LST with a reasonable quality compared to the Moderate Resolution Imaging Spectroradiometer (MODIS) LST data, it showed a relatively poor performance for the strong inversion and lapse rate conditions. To solve this problem, the LST retrieval algorithm (CSW_v2.0) was updated using the simulation results of radiative transfer model (MODTRAN 4.0) by considering the diurnal variations of air temperature. In general, the upgraded version, CSW_v3.0 showed a similar correlation coefficient between the prescribed LSTs and retrieved LSTs (0.99), the relatively smaller bias (from -0.03 K to-0.012 K) and the Root Mean Square Error (RMSE) (from 1.39 K to 1.138 K). Particularly, CSW_v3.0 improved the systematic problems of CSW_v2.0 that were encountered when temperature differences between LST and air temperature are very large and/or small (inversion layers and superadiabatic lapse rates), and when the brightness temperature differences and surface emissivity differences were large. The bias and RMSE of CSW_v2.0 were reduced by 10-30% in CSW_v3.0. The indirect validation results using the MODIS LST data showed that CSW_3.0 improved the retrieval accuracy of LST in terms of bias (from -0.629 K to -0.049 K) and RMSE (from 2.537 K to 2.502 K) compared to the CSW_v2.0.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.7
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• pp.717-722
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• 2011

The purpose of this study is to predict the residual stress in Al6061 during T6 heat treatment. In this study, the variable residual stress in case of the solid solution($530^{\circ}C$, 2h) and artificial ageing($175^{\circ}C$, 9h) of Al6061 subjected to T6 heat treatment is determined at different ageing times. A heat treatment experiment is conducted to determine the heat transfer coefficient, on the basis of which the residual stress during the T6 heat treatment is predicted. In order to take into account the relaxation of residual stress during artificial ageing, a Zener-Wert-Avrami function is used and elasto-plastic nonlinear analysis is conducted through FE-simulation. Further, the residual stress is measured by using the X-ray diffraction(XRD) method, and the result is compared with the result from the FE-simulation. It is found that the residual stress predicted form the FE-simulation is in good agreement with the residual stress measured by using the XRD method.

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.301-306
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• 2017

This study was carried out to investigate the residual level of 5-methyl-1,2,4-triazolo[3,4-b][1.3] benzothiazole (tricyclazole) and the amount of transfer to Korean cabbage grown in treated soil with tricyclazole. The field trial on Korean cabbage was done at two different green houses located in Gwangju (Field 1) and Yongin (Field 2). Soil and cabbage samples were collected at different days after soil treatment of tricyclazole with two different concentration levels, respectively. Average recoveries of tricyclazole ranged from 83.5 to 92.1% in soil and cabbage and the variation coefficient was 1.3-6.8%. The initial concentrations of tricyclazole in field 1 soil were 4.25 and 8.97 mg/kg and decreased to 2.48 and 4.26 mg/kg at 43 DAT (day after treatment) and 0.88 and 2.02 mg/kg and decreased to 0.43 and 0.98 mg/kg at 36 DAT in field 2, respectively. The half-life of tricyclazole was about 39.6 and 28.1 days for the low and high concentration of tricyclazole treated soils in field 1 and 27.9 and 17.2 days for the low and high concentration of tricyclazole treated soils in field 2, respectively. Residual levels of tricyclazole in Korean cabbage were ranged from 4.03 to 18.26 and from 8.26 to 35.08% of initial concentration in filed 1 and field 2 soils, respectively.

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.343-349
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• 2017

This study was conducted to investigate the residual level and the amount of transfer to lettuce grown in field condition treated with the 5-methyl-1,2,4-triazolo[3,4-b][1,3]benzothiazole (Azoxystrobin). The field trials on lettuce were carried out at two different green houses located in Gwangju (Field 1) and Yongin (Field 2). Soil and lettuce samples were collected at different days after soil treatment of azoxystrobin with two different concentrations, respectively. Average recoveries for azoxystrobin ranged from 86.9 to 113.6% from soil and lettuce with the variation coefficient of 0.1-4.6%. The initial concentrations of azoxystrobin in Gwangju soil were 9.20, 11.00 mg/kg and decreased to 1.36, 2.70 mg/kg at 43 DAT (days after treatment) in field 1, while 1.06, 2.23 mg/kg decreased to 0.20 and 0.67 mg/kg at 36 DAT in field 2, respectively. The half-lives of azoxystrobin were about 19.4 and 23.3 days for the low and high concentration of azoxystrobin treated soils in field 1 and 11.5 and 17.8 days in field 2 soils, respectively. Residue levels of azoxystrobin in lettuce were not detected in filed 1 and field 2 soils, respectively.

• Journal of Energy Engineering
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• v.24 no.4
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• pp.124-129
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• 2015

An experimental study was performed estimating COP(Coefficient of Performance) of air-conditioning cycle using inverter scroll compressor with and without $Al_2O_3$ nano particle. All experiments were done for various compressor speeds from 1000~4000 rpm and used the inverter controller called CANDY to change the compressor rpm. The air-conditioning cycle components in the apparatus were used as same with components of YF hybrid car. To estimate the COP, this study measured the temperature and pressure at inlets and outlets of compressor, condenser, and evaporator. And also measured the compressor input power using Powermeter. Through the experiments, the maximum error to estimate COP was shown about ${\pm}6.09%$ at 3500rpm. The COP of refrigeration cycle with $Al_2O_3$ nano-particle was similar with that of the base cycle without nano-particle between 1000~3000 rpm of the compressor speed. But, This study showed that the COP of the cycle with $Al_2O_3$ over 3000 rpm of the compressor speed was higher than that of the base cycle due to the higher heat transfer rate increased in the evaporator from the higher oil flow rate inside the cycle as well known. Those results can be used the basic and fundamental data to design the air-conditioning cycle using inverter scroll compressor with $Al_2O_3$ nano particle.

• Journal of Bio-Environment Control
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• v.12 no.3
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• pp.107-113
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• 2003

This study was carried out to improve the performance of pre-developed heat recovery devices attached to exhaust-gas flue connected to combustion chamber of greenhouse heating system. Four different units were compared in the aspect of heat recovery performance; A-, B-, and C-types are exactly the same with the old ones reported in previous studies. D-type newly developed in this experiment is mainly different with the old ones in its heat exchange area and tube thickness. But airflow direction(U-turn) and pipe arrangement are similar with previous three types. The results are summarized as follows; 1. System performances in the aspect of heat recovery efficiency were estimated as 42.2% for A-type, 40.6% for B-type, 54.4% for C-type, and 69.2% for D-type. 2. There was not significant improvement of heat recovering efficiency between two different airflow directions inside the heat exchange system. But considering current technical conditions, straight air flow pattern has more advantage than hair-pin How pattern (U-turn f1ow). 3. The main factors influencing on heat recovery efficiency were presumably verified to be the total area of heat exchange surface, the thickness of ail-flow pipes, and the convective heat transfer coefficient influenced by airflow velocity under the conditions of allowable pipe durability and safety. 4. Desirable blower capacity for each type of heat recovery units were significantly different to each other. Therefore, the optimum airflow capacity should be determined by considering in economic aspect of electricity required together with the optimum heat recovery performance of given heat recovery systems.

• Korean Journal of Food Science and Technology
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• v.19 no.6
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• pp.486-491
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• 1987

The performance and applicability to food concentration of heat pump were investigated. During heating the water of spa from $43^{\circ}C$ to $51^{\circ}C$, COP's of heat pump (R-12, 150 HP) were 4.03 at heating part and 3.5 at cooling part. And, the efficiency of compressor (${\alpha}$) was 0.477 While the city water was heated to $39^{\circ}C$ by heat pump (R-22, 10 HP), its COP's were 3.0 at heating part and 1.87 at cooling part. During concentrations sucrose solution by centrifugal evaporator (ALFA-LAVAL CO, CTIB) with heat pump, heat capacity for condensating water vapor was required greater 15% than the latent heat for concentrating and then the overall heat transfer coefficient was $1196\;Kcal/m^{2}.\;h.\;^{\circ}C$. When low temperature concentration ($30-35^{\circ}C$, 28-40 Torr) of garlic extract was carried out by the water of $60^{\circ}C$ and $15^{\circ}C$ adjusted by heat pump, the ratio of heat capacity for concentrating vs. that for condensating of water vapor was 0.961.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.189-193
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• 1981

An apparatus for continuous measurements of sorption isotherm of dried food was manufactured to shorten the time required for equilibration. The apparatus was so designed that the temperature, air velocity and relative humidity in the experimental chamber could be controlled. The use of dynamic stream of conditioned air with a velocity of 0.2m/sec, instead of static atmosphere, allowed a faster equilibration of dried filefish muscle at $25^{\circ}C$. The mean time necessary for the equilibration of dried filefish muscle at the water activity of a given state to a higher water activity was about 45 hours. The monolayer moisture content of dried filefish muscle calculated from BET-equation was 0.092 kg water /kg dry matter at $25^{\circ}C$.

• KSBB Journal
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• v.24 no.3
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• pp.303-311
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• 2009

A scaling up study for the exopolysaccharide (EPS) production by submerged culture of Ganoderma lucidum was carried out in jar fermenter systems (2.6, 20 and 75 L) under bi-staged pH process. Profiles of dissolved oxygen (DO) and volumetric coefficient of oxygen transfer ($k_La$) as a function of operating variables (agitation speed and aeration rate) was investigated, and a correlation between $k_La$ and operating variables was analysed statistically. Under bi-staged pH process, no limitation of DO was observed at agitation speeds tested in the range of 200 and 600 rpm, and the highest EPS production was obtained at the level of DO of $40{\sim}80%$. From the regression analysis, the relation between $k_La$, gas velocity (Vs), stirrer speed (N) and impeller diameter (Di) could be expressed as : $$k_La=0.555{\times}Vs^{0.42}{\times}(N^3{\times}Di^2)^{0.33}\;(R^2=0.925,\;p<0.05)$$ It was found that under 2.6 L jar fermenter, the optimum agitation speed and aeration rate was 400 rpm and 1 vvm, respectively, obtaining the EPS production of 15.43 g/L. Under the submerged cultivation of G. lucidum in jar fermenters of $2.6{\sim}75\;L$, the similar EPS yields at each fermenter were achieved during scaling up based on $k_La$, and $k_La$ value for maximum EPS production was $85.4{\pm}26.70\;h^{-1}$.