• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.1
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• pp.1-8
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• 2000

The objectives of this study were to investigate weather conditions which induced discolored grains and viviparous germination, and to evaluate yield responses following viviparous germination during mid- and late- ripening stage, the submergence during reproductive growth stage, and lodging in the yellow ripe stage. Weather conditions which caused glume discoloration at heading stage were 21.3-26.4$^{\circ}C$ in average temperature, 75.2-98.4% in relative humidity, 19.3 in transpiration coefficient and 10.8-13.8 m/sec. in wind speed. Yield reduction was 26-27% and 10~17%, respectively, when the glume discoloration rates were 63.2-65.7% and 38.3-45.2%, obviously due to the decrease in percent of fertile grain and ripening ratio. Weather conditions during continuous rain for 7 days were 96% in relative humidity, 18.9$^{\circ}C$ in average temperature, 21.9$^{\circ}C$ in maximum temperature, and 16.8$^{\circ}C$ in minimum temperature, causing the most viviparous germination in Juanbyeo(45.5%), followed by Jinbubyeo(14.5%), Bongkwangbyeo(14.2%), and Obongbyeo(12.6%). Lateral tillers started to occur when the submergence at the depth of 1.5-2 m lasted one day during the reproductive growth stage. The submergence for 2-3 days at 3-4 m of water depth induced 269-571 lateral tillers/m$^2$, supporting 32-52% of the total yield. The rice yield in the paddy fields which were left under the lodging conditions until harvesting was not different compared to that of the paddy fields which were kept upright by tieing them together after lodging, but perfect grain ratio decreased about 9.1% in the transplanting culture and 12.5% in the direct seeding culture on dry paddy field because of the increase in immature grains.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.2
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• pp.61-71
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• 2009

Most deciduous trees in temperate zone are dormant during the winter to overcome cold and dry environment. Dormancy of deciduous fruit trees is usually separated into a period of rest by physiological conditions and a period of quiescence by unfavorable environmental conditions. Inconsistent and fewer budburst in pear orchards has been reported recently in South Korea and Japan and the insufficient chilling due to warmer winters is suspected to play a role. An accurate prediction of the flowering time under the climate change scenarios may be critical to the planning of adaptation strategy for the pear industry in the future. However, existing methods for the prediction of budburst depend on the spring temperature, neglecting potential effects of warmer winters on the rest release and subsequent budburst. We adapted a dormancy clock model which uses daily temperature data to calculate the thermal time for simulating winter phenology of deciduous trees and tested the feasibility of this model in predicting budburst and flowering of Niitaka pear, one of the favorite cultivars in Korea. In order to derive the model parameter values suitable for Niitaka, the mean time for the rest release was estimated by observing budburst of field collected twigs in a controlled environment. The thermal time (in chill-days) was calculated and accumulated by a predefined temperature range from fall harvest until the chilling requirement (maximum accumulated chill-days in a negative number) is met. The chilling requirement is then offset by anti-chill days (in positive numbers) until the accumulated chill-days become null, which is assumed to be the budburst date. Calculations were repeated with arbitrary threshold temperatures from $4^{\circ}C$ to $10^{\circ}C$ (at an interval of 0.1), and a set of threshold temperature and chilling requirement was selected when the estimated budburst date coincides with the field observation. A heating requirement (in accumulation of anti-chill days since budburst) for flowering was also determined from an experiment based on historical observations. The dormancy clock model optimized with the selected parameter values was used to predict flowering of Niitaka pear grown in Suwon for the recent 9 years. The predicted dates for full bloom were within the range of the observed dates with 1.9 days of root mean square error.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.3
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• pp.361-366
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• 2012

This paper presents speed control of an electric motorcycle using a fuzzy controller. The electric motorcycle required to meet not only fast throttle response but also stability, when it is on a cruise. However, a 1.5KW (50cc) electric motorcycles selling in the current market are difficult to cruise under the following conditions which are occupant's weight, load weight, wind resistance and road conditions (dirt roads, asphalt road). Because of these reasons, the rapid speed changing occurs in uphill and downhill road. To solve these problems, The input value for Improved fuzzy controller use the speed error and error variance. The output value for improved fuzzy controller uses Q-axis of the motor controlled variable. The D-axis of the motor output for improved fuzzy control uses D-axis controlled variable in proportional to Q-axis controlled variable. Improved fuzzy controller drives the electric motorcycle equipped with IPMSM. The control subject used in this paper is a 1.5KW electric motorcycle equipped with improved fuzzy controller that was used to control the motor speed. To control IPMSM Type of motor torque, D, Q-axis current controller was used. The Fuzzy controller using the proposed algorithm is demonstrated by experimental hardware simulator.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.1
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• pp.96-102
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• 1981

Effect of shifting planting-time and different nitrogen on the yield and characteristics of plant growth in safflower, Chrthamus Tinctorius L. This study was carried out to investigate the optimum sowing-date and the ecological variations due to differerent amount of nitrogen for safflower on the Experiment Farm of Sang Ji college from March 17 to may 16, 1980, sowing seeds with an interval of 10 days and the amount of nitrogen were applied in 5 levels (Non, half-standard, standard, one and half-ordinary amount-No and twice amount). The triple super phosphate and pottassium chloride were applied only in standard amount. The results obtained are summarized as follows; 1. As sowing-date was delayed, the germination-ratio decreased, germinating speed increased, and the time required to attain the most vigorous germinating stage and days required for germination shortened. 2. Plant height, number of branch and stem diameter showed a decrease as sowing-date was delayed. And at the same time, plant height and number of branch showed a tendency to increase as amount of nitrogen was increased. 3. As sowing-date was delayed, the number of pods and the weight of 1000-grains were decreased. Moreover, the earlier sowing-date was, the more it increased. And as amount of nitrogen was increased, number of pods and yield also were strikingly increased. 4. The fresh-weight of flower with orange and orange-red colour, as influenced by the different sowing-date, was found out to be largest at the begining of April. But increasing amount of nitrogen did not show influence upon the promotion of flowering. 5. Judging from the results reported above, the optimum sowing-date of safflower seemed to be the begining of April; also the culture of safflower seemed to be the effects of much amount of nitrogen.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.22 no.3
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• pp.95-102
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• 2016

This study investigated the effects of the oxygen permeability of vacuum packaging film and the storage temperature on the quality and shelf life of Hamburg steaks during storage for 14 days. Control samples (C) were packaged in a polyamide/polyethylene (PA/PE) film and stored at $5^{\circ}C$. Treatment samples were either packaged in an ethylene vinyl alcohol/polyethylene (EVOH/PE) copolymer film and stored at $5^{\circ}C$ (T1), and in a PA/PE film and stored at $-18^{\circ}C$ (T2). The initial total plate count (TPC) was 3.6 log cfu/g. In T1 samples, TPC and Brochothrix thermosphacta counts were increased, similar to those in C samples, whereas Pseudomonas spp. counts were significantly lower than those in C samples during storage. Over the storage period, the volatile basic nitrogen values increased most rapidly in C samples, followed by T1 and then T2 samples. The values of thiobarbituric acid reactive substances steadily increased in all samples during storage. The colour parameters were not significantly different among the samples during storage. T1 samples maintained sensory qualities in flavour and off-odour parameters for two days longer than C samples did. At day 12, T2 samples were evaluated as being below the marketability score of 5.0 for texture. In conclusion, using high oxygen barrier films like EVOH/PE copolymer for packaging Hamburg steaks could extend the sensory qualities in view of flavour and off-odour during chilled storage. However, frozen storage at $-18^{\circ}C$ is recommended when the storage period is extended beyond 14 days at $5^{\circ}C$.

• Food Science and Preservation
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• v.17 no.4
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• pp.471-477
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• 2010

We explored the effects of curing and smoking conditions on the shelf life of Dombaeki (shark meat). Dombaeki cured for 12 h in an aqueous solution containing (per 100 ml) salt 5.6 g, sugar 14 g, and garlic powder 0.6 g, showed the best sensory quality among various samples cured for 0, 3, 6, 9, 12 or 24 hours. The optimum conditions for preparation of smoked Dombaeki (SD) were drying at $60^{\circ}C$ for 30 min, followed by cooking at $80^{\circ}C$ for 30 min and smoking at $65^{\circ}C$ for 40 min, as judged by sensory evaluation of taste, color, flavor, texture, and overall acceptability. The volatile basic nitrogen content of air- or vacuum-packed unsmoked Dombaeki (NSD) was above 20 mg% after storage for either 12 days or 5 weeks. However, the nitrogen contents of air- and vacuum-packed SD were less than 20 mg% after either 21 days or 10 weeks of storage at $10^{\circ}C$. The DPPH free radical-scavenging ability of SD (73.9%) was significantly higher than that of unsmoked meat (4.54%). The total polyphenol content of SD (745.6 g/g) was about 4-fold greater than that of unsmoked meat (179.5 g/g).The viable bacterial count of air- or vacuum-packed unsmoked meat was over $10^6\;CFU/g$ after storage for either 12 days or 5 weeks. However, air- or vacuum-packed SD had counts under $10^4\;CFU/g$ at all storage times tested. Changes in coliform bacterial levels paralleled those of total viable cells. The sensory quality (taste, color, flavor, appearance, texture, and overall acceptability) of SD was significantly better than that of NSD.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.81-87
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• 2015

The present study was aimed to predict the pre-harvest residue limits (PHRLs) of pyrimethanil (fungicide) and methoxyfenozide (insecticide) in grape, and to estimate their biological half-lives and residual characteristics. The pesticides were sprayed once on grape in two different fields 10 days before harvest. At the end of 0, 1, 2, 3, 5, 7 and 10 days after application, samples were harvested for further analysis. The residual pesticides were extracted with acetonitrile and partitioned with dichloromethane, and the high-performance liquid chromatography with diode array detector (HPLC/DAD) was employed for the residue analysis. The results obtained in the present study show that the limit of detection of both pesticides were found to be $0.01mg\;kg^{-1}$. The recoveries of these pesticides were ranged between 80.6% and 102.5% with coefficient of variation lower than 10%. The biological half-lives of both pesticides were observed in field 1 and field 2 which shows 7.7 and 7.4 days for pyrimethanil and 5.1 and 6.1 days for methoxyfenozide, respectively. Further, the PHRL of pyrimethanil and methoxyfenozide was found to be $8.90mg\;kg^{-1}$ and $5.51mg\;kg^{-1}$, respectively at 10 days before harvest. Consequently, the present study suggests that the residual amounts of both pesticides will be lower than the maximum residue limits (MRLs) when grape is harvested.

• Korean Journal of Agricultural Science
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• v.7 no.2
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• pp.103-108
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• 1980

In order to elucidate the source of bacterial contamination during processing U. H. T. milk and to ensure its hygienic control, bacterial numbers were determined each step of the processes on the milks, water, tanks and pipe lines, and environments. The results obtained were as follows. 1. The viable numbers of mesophilic bacteria were $1.2{\sim}1.9{\times}10^7/ml$ of milk in the storage tank and in pipe line connected to the preheater. These were decreased to $7.0{\times}10cells{\sim}3.4{\times}10^2cells/ml$ after preheating and homogenization, and to $1.0{\times}10cells/ml$ after sterilization, then increased up to $1.2{\times}10^2cells/ml$ after packing. 2. The numbers of thermophilic bacteria were $5.0{\times}10cells{\sim}1.0{\times}10^2cells/ml$ of milk before preheating ; $3.0{\sim}5.0{\times}10cells/ml$ after homogenization ; none in the sterilizer and surge tank ; and $1.0{\sim}8.0{\times}10cells/ml$ after packing. 3. The levels of psychrophilic bacteria were $1.0{\sim}3.7{\times}10^6cells/ml$ of milk before preheating ; $1.0{\sim}4.0{\times}10cells/ml$ after homogenization ; $1.0{\times}10cells/ml$ after sterilization ; and $2.0{\times}10cells{\sim}2.5{\times}10^2cells/ml$ after packing. 4. No coliform bacteria were detected after sterilization, while the level before preheating was $2.1{\times}10^4cells{\sim}6.5{\times}10^5cells/ml$ of milk. 5. The level of mesophiles was $3.0{\times}10cells{\sim}7.4{\times}10^2cells$ in the environmental air, water supply, and unfilled packs and bottles ; that of thermophiles $1.0{\sim}3.0{\times}10cells$ in the air and water ; that of psychrophiles $1.0{\times}10cells{\sim}1.0{\times}10^2cells$ in the air, water, packs and bottles ; however no coliform was detected.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.2
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• pp.113-119
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• 1989

In 1988 the tolerance of corn, sorghum, sorghum-sudangrass. and pearl millet hybrids to simazine and alachlor was tested in field during the growing season and pots during the summer and fall. In field and summer pot experiments(Exp.) the above mentioned four crops were tested at the ratios of simazine WP (50% ai, g/10a) ; alachlor EC (43.7% ai. ml/10a) of 130: 0, 100: 0, 70: 200, 0: 300 and 0: 400 and a sorghum hybrid was tested at 0, 50, 100, 200, 300, and 400ml/10a of alachlor and 70g/10a of simazine+ 200ml/10a of alachlor in fall pot Exp. In corn emergence rate, percent stand, plant height of seedlings, and dry matter(DM) yield were not affected by simazine and alachlor in all Exps. In sorghum and sorghum-sudangrass early growth and DM yield were not affected by simazine and alachlor in field Exp. In contrast, simazine reduced height and dry weight of seedlings slightly without any deterimental effects on emergence and survival rates. but alachlor reduced survival rate, plant height, and dry weight of seedlings significantly in summer pot Exp. In fall Exp. alachlor did not affect emergence rate of a sorghum hybrid, but survival rate, plant height, and dry weight of seedlings reduced with increased levels of alachlor when applied higher than 100ml/10a. In pearl millet simazine did not affect emergence rate, plant height, and DM yield in field, but reduced survival rate, plant height, and dry weight of seedlings in summer pot Exp. However, alachlor reduced DM yield significantly due to a lower percent stand even in the field. In summer pot Exp. although emeregence rate was slightly reduced, all seedlings were dead after emergence. Simazine did not control grasses such as Digitaria sanguinalis, Setaria viridis, Echinochloa crusgalli effectively, but controlled broadleaf weeds. Alachlor controlled all grasses, Porluraca oleracea, and Amaranthus mangostanus, but did not control Acalypha australis and Chenopodium album. A combination of simazine and alachlor controlled weeds more effectively than either simazine or alachlor alone.

• Korean journal of food and cookery science
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• v.19 no.2
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• pp.195-209
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• 2003

The purpose of this study was to identify the hazard analysis critical control point on food production and transportation flow, applied to home-delivered meals for the elderly. To carry out this study, 1) pan-fried oak mushroom and meat, soy sauce glazed hair tail, and roasted dodok were selected as high nutrient and preferred foods for the elderly and 2) time, temperature, and microbiological quality(standard plate count, coliform, Salmonella spp, Vibrio parahaemolyticus, Staphylococcus spp., Escherichia coli O157:H7, and Listeria monocytogenes) were measured at various phases of the home-delivered meal production and its transportation flows. The results of this experiments are as follows: The temperature measured at cooling phases during the home-delivered meal production flows was 19.2 ∼ 20.0$^{\circ}C$ for the pan- fried oak mushroom and meat and the roasted dodok and was 24.0 ∼ 25.2$^{\circ}C$ for the soy sauce glazed hair tail. These temperature were in the potentially dangerous zone. Microbiological analysis showed that S. spp. was higher in the raw ingredients, including oak mushroom, hair tail, radish, and dodok, than the standard limit. SPC was lower than the standard limit from cooking to transportation phase, but SPC increased significantly during the cooling and packaging phase. The level of coliform detected was far lower than the standard limit and was not detected at all during the transportation phase. Few S. spp. was detected in the pan-fried oak mushroom and meat, but was found in above standards limit during the wrap packaging phase in the soy sauce glazed hair tail and roasted dodok. The level decreased rapidly during the holding and transportation phase. Sal. spp., V. parahaemolyticus, S. spp., E. coli O157:H7, and L. monocytogenes were not detected. For the pan-fried oak mushroom and meat, the critical control points were during the purchasing and receiving of raw ingredients, cooling, and packaging phases. For the soy sauce glazed hair tail and roasted dodok, the critical control points were during the purchasing and receiving of raw ingredients, preparation, cooling, and packaging phases.