• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.6
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• pp.884-892
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• 2014

The purpose of this study was to investigate the drying characteristics and drying models of Ainsliaea acerifolia Sch. Bip. using far-infrared thin layer drying. Far-infrared thin layer drying test on Ainsliaea acerifolia Sch. Bip. was conducted at two air velocities of 0.6 and 0.8 m/sec, as well as three drying temperatures of 40, 45, and $50^{\circ}C$ respectively. The drying models were estimated using coefficient of determination and root mean square error. Drying characteristics were analyzed based on factors such as drying rate, leaf color changes, antioxidant activity, and contents of polyphenolics and flavonoids. The results revealed that increases in drying temperature and air velocity caused a reduction in drying time. The Thompson model was considered suitable for thin layer drying using far-infrared radiation for Ainsliaea accerifolia Sch. Bip. Greenness and yellowness values decreased and lightness values increased after far-infrared thin layer drying, and the color difference (${\Delta}E$) values at $40^{\circ}C$ were higher than those at $45^{\circ}C$ and $50^{\circ}C$. The antioxidant properties of Ainsliaea acerifolia Sch. Bip. decreased under all far-infrared thin layer drying conditions, and the highest polyphenolic content (37.9 mg/g), flavonoid content (22.7 mg/g), DPPH radical scavenging activity (32.5), and ABTS radical scavenging activity (31.1) were observed at a drying temperature of $40^{\circ}C$ with an air velocity of 0.8 m/sec.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.3
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• pp.299-306
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• 2014

Fresh edible sweet corns demand relatively short period to harvest fresh ears, which can allow farmers to make a choice sweet corns for various cropping systems. For this reason, we were to find the optimum planting date of late-planted sweet corns to sell fresh ears in the autumn linked to cropping system with winter crops, investigating yield and properties of marketable fresh ears and growth traits of sweet corns (cv. 'Godangok' and cv. 'Guseulok') depending on planting dates such as 10 July, 20 July, and 30 July in Suwon 2012 and 2013, respectively. The 20 July-planted sweet corns showed the most fresh ear yield. However, the 10 July-planted and the 30 July-planted had 32% less yield caused by consecutive rainfall from 10 July through 20 July, and 15% less yield due to low air temperature during ripening than the 20 July-planted, respectively. The 10 and 20 July-planted sweet corns had average 140g of a fresh ear weight and 15% heavier ear than the 30 July-planted. For the July-planted sweet corns, silking days after planting ($r=-0.80^{**}$), and harvesting days after silking ($r=-0.97^{**}$) and planting ($r=-0.91^{**}$) were highly negatively correlated with daily mean air temperature during the period, resulting in it takes 1,100 growing degree days (GDD) to harvest fresh ears from the July-planted sweet corns. The fresh ears of the 20 July-planted sweet corns are able to be harvested by early October. Therefore it will be a good choice for the cropping system based on winter vegetable cash crops such as temperate garlic and onion with medium or late maturity. Among three planting dates 20 July-planted sweet corns had the best field performance in every year considering fresh ear yield, ear size, and stability to grow.

• Korean Journal of Remote Sensing
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• v.27 no.4
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• pp.481-494
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• 2011

Investigation of the $CO_2$ exchange between biosphere and atmosphere at regional, continental, and global scales can be directed to combining remote sensing with carbon cycle process to estimate vegetation productivity. NASA Earth Observing System (EOS) currently produces a regular global estimate of gross primary productivity (GPP) and annual net primary productivity (NPP) of the entire terrestrial earth surface at 1 km spatial resolution. While the MODIS GPP algorithm uses meteorological data provided by the NASA Data Assimilation Office (DAO), the sub-pixel heterogeneity or complex terrain are generally reflected due to coarse spatial resolutions of the DAO data (a resolution of $1{\circ}\;{\times}\;1.25{\circ}$). In this study, we estimated inputs retrieved from MODIS products of the AQUA and TERRA satellites with 5 km spatial resolution for the purpose of finer GPP and/or NPP determinations. The derivatives included temperature, VPD, and solar radiation. Seven AmeriFlux data located in the Corn Belt region were obtained to use for evaluation of the input data from MODIS. MODIS-derived air temperature values showed a good agreement with ground-based observations. The mean error (ME) and coefficient of correlation (R) ranged from $-0.9^{\circ}C$ to $+5.2^{\circ}C$ and from 0.83 to 0.98, respectively. VPD somewhat coarsely agreed with tower observations (ME = -183.8 Pa ~ +382.1 Pa; R = 0.51 ~ 0.92). While MODIS-derived shortwave radiation showed a good correlation with observations, it was slightly overestimated (ME = -0.4 MJ $day^{-1}$ ~ +7.9 MJ $day^{-1}$; R = 0.67 ~ 0.97). Our results indicate that the use of inputs derived MODIS atmosphere and land products can provide a useful tool for estimating crop GPP.

• Journal of the Korean Vacuum Society
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• v.16 no.5
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• pp.359-365
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• 2007

In this paper we present a bottom-gate type of zinc oxide (ZnO) and Gallium (Ga) doped zinc oxide (GZO) based thin film transistors (TFTs) through applying a radio frequency (RF) magnetron sputtering method at room temperature. The gate leakage current can be reduced up to several ph by applying $SiO_2$ thermally grown instead of using new gate oxide materials. The root mean square (RMS) values of the ZnO and GZO film surface were measured as 1.07 nm and 1.65 nm, respectively. Also, the transmittances of the ZnO and GZO film were more than 80% and 75%, respectively, and they were changed as their film thickness. The ZnO and GZO film had a wurtzite structure that was arranged well as a (002) orientation. The ZnO TFT had a threshold voltage of 2.5 V, a field effect mobility of $0.027\;cm^2/(V{\cdot}s)$, a on/off ratio of $10^4$, a gate voltage swing of 17 V/decade and it operated in a enhancement mode. In case of the GZO TFT, it operated in a depletion mode with a threshold voltage of -3.4 V, a field effect mobility of $0.023\;cm^2/(V{\cdot}s)$, a on/off ratio of $2{\times}10^4$ and a gate voltage swing of 3.3 V/decade. We successfully demonstrated that the TFTs with the enhancement and depletion mode type can be fabricated by using pure ZnO and 1wt% Ga-doped ZnO.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.253-262
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• 2015

The sustainability of Cypripedium japonicum, a rare plant designated by the Korea Forest Service, is threatened due to artificial factors such as habitat loss and climate change etc. and internal factors such as changes in biological properties of the habitat etc. but conservation research has not been performed in South Korea. The objective of this study is to establish the species conservation strategies by analyzing the characteristics of their habitats, including: 1) Population characteristics, and 2) habitat analysis of the vegetation and abiotic environments. From April to September, 2014, population characteristics [density (stems $m^{-2}$), flowering rate (%), and leaf area ($cm^2$)] in Cypripedium japonicum habitats such as Chuncheon (CC), Hwacheon (HC), Muju (MJ), and Gwangyang (GY) and vegetation characteristics (plant sociological research and ordination analysis), and abiotic environments [temperature ($^{\circ}C$), relative humidity (%), transmitted light ($mol{\cdot}m^{-2}{\cdot}d^{-1}$) and canopy openness (%)] were measured. Cypripedium japonicum was mainly distributed at elevation 450 to 990 m and 5 to $30^{\circ}$ slope. Slope direction was shown as 0 to $110^{\circ}$. Habitats temperature (mean $18.94^{\circ}C$) was well matched to seasonal changes. Differences among sites showed greater level according to latitude difference. It showed the highest in habitat, GY located in the South. On the other hand, relative humidity (77.38%) didn't show much difference among sites. The average degree of canopy openness was 18.17%. It showed the highest at HC (22.1%) and the lowest at MJ (16.1%). The average degree of transmitted light was $9.1mol{\cdot}m^{-2}{\cdot}d^{-1}$. It showed the highest at CC ($10.6mol{\cdot}m^{-2}{\cdot}d^{-1}$) and the lowest at GY ($6.87mol{\cdot}m^{-2}{\cdot}d^{-1}$). Chlorophyll content showed average 26.12 SPAD. It showed the highest at MJ (30.64 SPAD value) and the lowest at HC (23.69 SPAD value). Leaf area was average $253.35cm^2$. It showed the highest at CC ($281.51cm^2$) and the lowest at HC ($238.23cm^2$).

• Korean Journal of Agricultural and Forest Meteorology
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• v.12 no.1
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• pp.11-22
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• 2010

According to IPCC 4th Assessment Report, concentration of carbon dioxide has been increasing by 30% since Industrial Revolution. Most of IPCC $CO_2$ emission scenarios estimate that the concentration will reach up to double of its present level within 100-year if the current tendency continues. The global warming has resulted in the agro-climate change over the Korean Peninsula as well. Accordingly, it is necessary to understand the future agro-climate induced by the increase of greenhouse gases in terms of the agro-climatic indices in the Korean peninsula. In this study, the future climate is simulated by an atmosphere/ocean/land surface/sea ice coupled general circulation climate model, Pusan National University Coupled General Circulation Model(hereafter, PNU CGCM), and by a regional weather prediction model, Weather Research and Forecasting Model(hereafter, WRF) for the purpose of a dynamical downscaling. The changes of the vegetable period and the crop growth period, defined as the total number of days of a year exceeding daily mean temperature of 5 and 10, respectively, have been analyzed. Our results estimate that the beginning date of vegetable and crop growth periods get earlier by 3.7 and 17 days, respectively, in spring under the $CO_2$-doubled climate. In most of the Korean peninsula, the predicted frost days in spring decrease by 10 days. Climatic production index (CPI), which closely represent the productivity of rice, tends to increase in the double $CO_2$ climate. Thus, it is suggested that the future $CO_2$ doubled climate might be favorable for crops due to the decrease of frost days in spring, and increased temperature and insolation during the heading date as we expect from the increased CPI.

• Journal of Food Hygiene and Safety
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• v.35 no.5
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• pp.468-476
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• 2020

We aimed to analyze the microbiological quality of the ready-to-eat (RTE) side dishes collected from traditional markets, supermarkets, and cafeterias in Gyeonggi-do in 2019. A total of 108 samples were analyzed for total aerobic bacterial counts, coliforms and foodborne pathogens depending on place of purchase and cooking methods. Results show that Bacillus cereus was detected in 14 (12.9%) out of 108 samples of side dishes, while no other foodborne pathogens were detected. The mean detected level (range) of total aerobic bacteria depending on place of purchase was 5.8 log CFU/g (3.0 to 8.2 log CFU/g) for traditional markets, 4.3 log CFU/g (2.4 to 7.8 log CFU/g) for supermarkets, and 3.80 log CFU/g (0.0 to 6.8 log CFU/g) for cafeterias, indicating that there was a significant (P<0.05) difference in total aerobic bacterial counts among places of purchase. Among the samples, the highest counts of total aerobic bacteria and coliforms were detected in saengchae (raw vegetables), followed by namul (seasoned herbs, vegetables), bokkeum (stir-fried foods), and jorim (foods cooked in soy sauce). The growth of total aerobic bacteria in seasoned soybean sprouts was inhibited when the sprouts were stored at 4℃ up to 24 h, whereas bacteria rapidly grew at 20 and 35℃ after 3 and 6 h, respectively. These results reveal that storage temperature might play a significant role for the microbiological quality of seasoned soybean sprouts when they are sold in markets. Thus, this study suggests that RTE side dishes should be stored at refrigerated temperature when being sold at markets as well as after purchasing to improve their microbiological quality.

• Journal of The Korean Society of Grassland and Forage Science
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• v.37 no.2
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• pp.145-153
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• 2017

This study was aimed to find yield prediction model of Italian ryegrass using climate big data and geographic information. After that, mapping the predicted yield results using Geographic Information System (GIS) as follows; First, forage data were collected; second, the climate information, which was matched with forage data according to year and location, was gathered from the Korean Metrology Administration (KMA) as big data; third, the climate layers used for GIS were constructed; fourth, the yield prediction equation was estimated for the climate layers. Finally, the prediction model was evaluated in aspect of fitness and accuracy. As a result, the fitness of the model ($R^2$) was between 27% to 95% in relation to cultivated locations. In Suwon (n=321), the model was; DMY = 158.63AGD -8.82AAT +169.09SGD - 8.03SAT +184.59SRD -13,352.24 (DMY: Dry Matter Yield, AGD: Autumnal Growing Days, SGD: Spring Growing Days, SAT: Spring Accumulated Temperature, SRD: Spring Rainfall Days). Furthermore, DMY was predicted as $9,790{\pm}120$ (kg/ha) for the mean DMY(9,790 kg/ha). During mapping, the yield of inland areas were relatively greater than that of coastal areas except of Jeju Island, furthermore, northeastern areas, which was mountainous, had lain no cultivations due to weak cold tolerance. In this study, even though the yield prediction modeling and mapping were only performed in several particular locations limited to the data situation as a startup research in the Republic of Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.149-154
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• 1992

Buckwheat has been a popular favorite food crop in Korea for a long time. The objective of the study was to investigate the effects of climatic conditions and cultural methods on grain yields of summer buckwheat variety Sinnong 1 planted during the spring season in Suwon, Korea from 1989 to 1991. Frost minimum temperature of late April was -0.3$^{\circ}C$ in 1990 being very low as compared with 3.7$^{\circ}C$ of the normal year, and affected early growth of the seedlings emerging from the soil surface. In late May of 1990, the frost minimum temperature was 7.3$^{\circ}C$ being low as compared with 8.8$^{\circ}C$ of the normal year, and also induced cold injury to fertilization and grain filling. Total precipitation 374.5mm of mid and late June, 1990 provided serious damage to the grain filling and maturing buckwheat seeds and along with causing seed sprouting before harvest. However, the climates of 1989 and 1991 were very good for the growth and development of spring-sown buckwheats. When summer buckwheat cultivar Sinnong 1 was planted on April 20, 1989, its highest grain yields 268-292kg /10a were harvested from the plots of seeding rate 8kg /10a, drill seeding and polyethylene film mulching, and the mean grain yield of the plots was 238kg /10a in 1989, but 64.3kg in Suwon, and 40.2kg /10a in Muan in 1990. In 1991 maximum grain yield 277kg /10a was produced from the April 15 planted and vinyl-mulched plot, and 255kg /10a from the April 25 planted and non-mulched plot. Herbicide Alachlor-sprayed plots produced lower grain yields than no weed control and manual weeding plots. Mechanized drill-seeding saved 83～84% in planting hours as compared with manual broadcasting 21.6 hours /ha, and produced 9% more in grain yields from the two-season croppings of mechanized drill-seeding culture being 364kg /10a in total yields per year.

• Journal of the Korean association of regional geographers
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• v.5 no.2
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• pp.133-142
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• 1999

The wetland is very important ecologically as a habitat of diverse organisms. The purpose of this paper is to elucidate the morphogenetic environment of Jilmoe Bog found in the Odae Mountain National Park Jilmoe Bog is located in the high etchplain(1,060m) where Daebo Granite which had intruded in Jura epoch of Mesozoic era has weathered deeply and has uplifted in the Tertiary. The annual mean temperature of study area is $5.3^{\circ}C$, the annual precipitation is 2,888mm. The minimun temperature of the coldest month(january) is below $-30^{\circ}C$ and the depth of frozen soil is over 1.6m. Jilmoe bog consists of a large bog and a small bog. The length of the large bog is 63m and its width is 42m. The basal surface of Jilmoe bog is uneven. Jilmoe bog is a string bog fanned due to frost actions. In String bog, its surface is wavy with stepped dry hills and net-like troughs crossing hill slope. It seems that string bog is related to the permofrost or seasonal permofrost of cold conifer forest(taiga) zone(where the depth of frozen soil is very deep in the least in winters). String bog is a kind of thermokarst that frozen soil thaws differentially locally in declining permofrost and ground surface becomes irregular. There is turf-banked terracette of width $30{\sim}40cm$ in the headwall of small cirque-type nivation hollow formed at footslope of Maebong mountain around Jilmoe bog. This turf-banked terracette is formed by the frost growth of soil water below grass mat in periglacial climate environment. Where water is plentiful such as a nivation follow${\sim}$valley corridor and a headwall of valley, turf patterned grounds of width $30{\sim}50cm$ are found. This turf patterned ground is 'unclassified patterned ground', earth hummock. In conclusion, Jilmoe bog is a string bog of thermokarst that the relief of ground surface is irregular according to locally differentially thawing of permofrost(frozen soil). Jilmoe bog is high moor, its surroundings belongs to periglacial environment that turf-banked terracette and turf patterned ground are fanned actively.