• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.2
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• pp.198-208
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• 1992

Recently, a nursery mat made from rock wool has realized transplanting of the younger seedlings with the ordinary transplanting machines for Chibyo and Chubyo(3 and 4～5 leaved seedling, respectively). The seedlings defined as the 'Nyubyo' or 'Nursling seedlings' became possible to achieve economic profits from the reduction in both working time and costs. It being widely noticed as a strategy to solve the difficulties in current rice cultivation. The nursling seedlings are 1.4 to 2.5 leaves and height at 4.5 to 7cm, grown 4 to 7 days after seeding. They maintain still up to 50 to 80% of their nutrients in the endosperm, and can grow by using only their own nutrients for a certain period of time after transplanting. Nursling seedlings take 2 days in the nursery chamber at 32$^{\circ}C$ after seeding, and 2 days in the greening house at $25^{\circ}C$. This is only 4 days, all together, to make the nursling seedlings of 1.5 leaves which are ready for transplanting. Watering is only needed once at the sowing time. It only takes 1 or 2 waterings even to raise a seedlings for a period of 7 days. The number of nursery boxes can be reduced because it is possible to sow more densely(220 to 240g per box), thus it only needs seedlings of 15 to 16 boxes per 10 a which leads to a reduction in facilities and space needed. Temperature during the nursery period can be artificially adjusted more precisely which may lead to the prevention of temperature stress. The nursling seedlings can root rapid by because the crown roots from the coleoptile node begin to emerge immediately after transplanting. They show strong resistance to low temperature (12$^{\circ}C$) and deep-planting. There is no danger in the rooting of the seedlings even if half of their height is buried into the soil. Moreover, it can root at a rate of up to 65 to 80% even if the full height of the seedlings is buried. They show also strong resistance to submergence (10～15cm). The nursling seedlings tend to grow by producing tillers from lower nodes. It is therefore, necessary to control to keep the proper numbers of tillers per unit area. They have no fear in the delay of heading and their yield components can be so well balanced that the same level of yield was achieved with the nursling seedlings compared to that with Chibyo. It was further suggested that if the surplus tillers can be avoided by such cultivation practices, the number of grain per panicle can be kept greater and higher yield can be realized. Practical experiments with the nursling seedlings conducted in 1989 and 1990 by farmers in various areas showed exciting results. The nursling seedlings will become widely spread, or at least occupy an important position in Japanese and also in Korean rice cultivation techniques.tivation techniques.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.1
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• pp.60-65
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• 1982

In order to observe the degree and response of drought-resistance and its physiological mechanism in barley and wheat seedling stage, 5 species (16 cultivars) were tested for the changes of nitrate reductase and protease activity and the accumulation of free proline, by being subjected to water stress by withholding watering for 8 days at 10 days (at the 3rd leaf stage) after emergence and by imposing water stress to the excised first leaf by polyethyleneglycol solution (osmotic potential, -20 bars) for 48 hours. The average rate of decrease of all cultivars was 42% in nitrate reductase activity and 73% in protease activity. But proline content in water stress was increased 10 folds more than that of control. The decrease4 rate of nitrate reductase activity in 5 species was in the order of wheat < rye < covered barley < naked barley < two-row barley: wheat being the lowest. The decreased rate of protease activity in 5 species was in the order of wheat > rye > two-row barley > covered barley > naked barley: wheat being the" heighest. The accumulated amount of free proline in 5 species by water stress was in the order of wheat > covered barley > rye > naked barley > two-row barley. And the increased ratio (folds) of free proline of water stress to control was in the order of rye(13) > wheat. covered barley(11) > naked barley(99) > two-row barley(7): rye being the highest. In terms of the enzymatic activity and the physiotically adaptive metabolism during the processing leading to drought-resistance, the degree of drought-resistance of 5 species to water stress at seedling stage was shown to be in the order of wheat > rye > covered barley > naked barley > two-row barley.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.1
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• pp.28-33
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• 2008

Traditionally mungbean (Vigna radiata L.) sprouts has been stored after dehydration to decrease their decay. The study was done to determine the effect of watering for final 12 hours of harvest day on morphological characters and color of mungbean sprouts. The seeds of cv. Zhong Lu 1 were soaked in 50 ppm BA solution immediately before 4 hour aeration and then cultured for 6 days, when water-supplied for final 12 hours or not. After packaged with PE envelops, the sprouts stored 5 days at $8^{\circ}C$, and their morphological characters, fresh and dry weights, and colors were measured everyday. Compared to non-water supplied, water supplied sprouts had thicker hypocotyl diameter in middle part, and higher total fresh weight due to increment of cotyledon and hypocotyl ones although the two sprouts did nearly same in other characters. Only nonwater supplied sprouts showed higher color b value in hypocotyl than water supplied ones although there were not significant differences between them in other color-related characters, meaning that the latter ones were more rapidly decayed during their storage. In non-water supplied sprouts, number of lateral roots, hypocotyl and root lengths, total fresh weight, brightness of hypocotyl and root was decreased since 3 days after storage but cutting resistance of hypocotyl was done since 5 days.

• Fire Science and Engineering
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• v.29 no.2
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• pp.79-83
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• 2015

The fire accident is a representative type of disaster that can largely impact on business. Therefore, precautionary measures and rapid initial response is very important when a disaster occurs. The storage of porous combustibles is inevitable in coal yard, plywood processing industry, and others that are currently operating. Initial fire fighting of fire and identifying the ignition point in such a porous combustible storage space are so difficult that if the initial response is failed, being led to deep-seated fire, surface fire is likely to result in secondary damage. In addition, deep-seated fire can cause personal injuries and property damage due to a large amount of toxic gases and reignition. Therefore damage reduction measures is required around the storage space to handle a porous flammable. Improving the penetration performance of the concentration of the surfactant is carried out as underlying study, which is about an deep-seated fire extinguishing efficiency augmentation when using wetting agents. The porous materials used in the experiments is radiata pine wood flour, which occupies more than 75% of the domestic wood market. Fire fighting water is selected as Butyl Di Glycol (BDG), which is being used for infiltration extinguishing agent, and the experiment was carried out by producing a standard solution. The experiment was carried out on the basis of the Deep-Seated Fire Test of NFPA 18. The amount of watering, porous material to the internal amount of penetration, and runoff measurement out of the porous material was conducted. According to experimental results, as the surface tension is reduced, the surfactant concentration macroscopic penetration rate decreases, but infiltration to a porous material is shown to have growth characteristics.

• Korean Journal of Medicinal Crop Science
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• v.4 no.4
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• pp.288-293
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• 1996

This study was investigated to obtain basic information for the development of irrigation plans in upland cultivation of Wasabi. Changes of stomatal conductivity and photosynthetic rate of Wasabi, and of the soil water potential during withholding watering were analysed. The stomatal conductivity of Wasabi at $1000{\mu}Em^{-2}s^{-1}$ light intensity was $70mmolem^{-2}s^{-1}$, which was about 49% lower than that of Chinese cabbage, $138mmolem^{-2}s^{-1}$. The temporal changes of light intensity during the daytime did not influence the stomatal conductivity. The soil water potential that decreased stomatal conductivity in Wasabi was about - 50kPa at 10 AM, and about - 30kPa at 3 PM. The photosynthetic rate of Wasabi at$1000{\mu}Em^{-2}s^{-1}$ light intensity was $7.6mgdm^{-2}hr^{-1}$, which was about 50% lower than that of Chinese cabbage, $15.3mgdm^{-2}hr^{-1}$. The duration required for a stable photosynthetic rate was longer in Wasabi than in Chinese cabbage. The soil water potential that decreased photosynthetic rate in Wasabi was about - 50kPa at 10 AM, and about - 30kPa at 3 PM. The stomatal conductivity and photosynthetic rate showed significant positive correlation at various soil water potential. The results indicated that irrigation in wasabi could be done during the daytime when the soil water potential is above - 30kPa, which does not decrease stomatal conductivity and photosynthesis in Wasabi.

• Korean Journal of Community Nutrition
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• v.7 no.2
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• pp.177-187
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• 2002

This study was done to determine the factors associated with childhood overweight in 721 sixth grade elementary school students, in Busan. The students' heights, weights, waist circumferences and triceps-skinfold thicknesses were measured using standard techniques. Other data were collected using a questionnaire that included information about physical activity, television watching, and the amount of exorcise taken during leisure times, family history of diseases related to obesity: social data including family income, parents'education and occupations, eating behaviors; parental weights and heights; and parental activity levels. Childhood overweight was defined as a body mass index at or above the 85th percentile for age and sex. The prevalence of overweight revealed no significant difference between sexes, (24.2% in boys and 22.03% in girls). The risk of childhood overweight was significantly greater if either the mother or the father were overweight. The odds ratio for childhood overweight associated with maternal overweight was 5.045 (94% CI : 3.262-7.801), and 2.727 (95% CI : 1.764-4.218) was the case for parental overweight. Children having a history of hear diseases had higher odds ratios than those who did not. The odds ratios for overweight associated with income were not different. However, a higher odds ratio for overweight was observed in children whose fathers had only an elementary or middle school education than those whore fathers had a high school or college education. Children whose fathers' occupations were service workers or shopkeepers (OR : 3.314, 95% C = 1.851-5.934) or had no occupation (OR = 3.756, 95% CI : 1.898-7.430) had a treater risk of overweight than those whose fathers'were professionals or once workers. The risk of overweight increased in children having more irregular meal times and faster eating times, rather than those having an intake pattern of high energy and sugar containing floods. The amount of exercise taken during leisure times, and daily physical activity showed no difference between overweight and non-overweight children. However, television watching time, especially on weekends, was greater in overweight children than in non-overweight children. Television watching time was positively correlated with BMI, triceps-skin(31d thickness, waist circumference and waist/height ratio. Therefore, television watching was found to be a useful predictor of overweight in children. Television watching in children was negatively related to paternal activity levels, and positively related to parental television watching time. In fact, fathers whose children were overweight were physically less active than fathers whose children were non-overweight. Parents appeared to be a strong influence on their children's physical activity levels. In conclusion, a low family social class, defined on the basis of the father's occupation or education, parental overweight, increased television watching, and unhealthy physical activity levels in parents were all considered risk factors for childhood overweight. Among these, television watching time and lack of physical activity were considered to be the most important risk factors that could be easily modified for the prevention of and intervention in, overweight in children.

• The Korean Journal of Zoology
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• v.39 no.1
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• pp.98-105
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• 1996

Studies on thermal adaptation postulate that optimal temperature of physiological properties matches a usually experienced body temperature (Tb) of organisms. Hibernating bats maintain Tb's that are slighdy higher than ambient temperatures (9$^{\circ}$-12$^{\circ}$C) of their wintering sites. To test the hypothesis that muscle function is adjusted to the Tb range of the hibernating animals, we examined contractile function of the biceps brachil muscle of Korean greater horseshoe bats, Rhinolophus ferrumequlnum korai (n = 5) at tissue temperatures between 1O$^{\circ}$ and 35$^{\circ}$C. Relative tetanic force (% of maximum force) was highest at temperatures of 1O$^{\circ}$-15$^{\circ}$C, which match well their Tb's during hibernation. Because non-hibernating endotherms with Tb of around 37$^{\circ}$C show the optimal temperature for muscle force over 30$^{\circ}$-40$^{\circ}$C, our results strongly suggest that the flight muscle of the bats may exhibit thermal adjustments according to their seasonal Tb's. The capacity to generate strong force at such low body temperatures may be adaptive, because bats must have muscles functioning to fly for occasional watering or excretion, or to move away from potential predators during hibernation.

• FLOWER RESEARCH JOURNAL
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• v.18 no.4
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• pp.225-230
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• 2010

This study was conducted to increase the income of cactus farm by selecting cheaper and better media than the peat moss using for Gymnocalycium mihanovichii 'Huhong'. We cultivated Gymnocalycium mihanovichii 'Huhong' on 10 kinds of media (peat moss, culture medium, coco peat, sphagnum moss, hydro ton, hydro cray, hydro bal, hugato, vermiculite, perlite) and analyzed media's physiochemical factors and growth, betacyanin. The results were as follows: In case of media's physical condition planting Gymnocalycium mihanovichii 'Huhong' after 90 days, an approximate value with peat moss is culture medium and coco peat. Also, coco peat has no change in chemical media. The rate of growth and development is high in Coco peat while overall culture medium and coco peat was seen lower growth. The level of betacyanin in subirrigation is higher than overhead irrigation. Meanwhile, hugato among 10 kinds of media has high value in both of overhead irrigation and bottom watering. Thus, culture medium and coco peat is proper for alternation of peat moss due to similar value with peat moss. And coco peat is favorable to media, growth condition, pigment.

• Bulletin of the Society of Naval Architects of Korea
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• v.6 no.1
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• pp.25-34
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• 1969

From viewpoints of over-all ship economy the straight framed V-bottom hull forms with chines are considered to be attractive even for usual commercial vessels, because increments of resistance over that of round hull forms, if any, can be well compensated with reduction in construction cost.[1] To investigate the influences of both prismatic coefficient and chine elevation on resistance performance, three models of straight-framed V-bottom hull forms which are similar to Prof. C. Ridgely-Nevitt's W-18, W-8, and W-20[2],[3] in size and hull form coefficients were tested at the SNU Ship Model Towing Tank for resistance measurements. They are of Cp=0.60, 0.65 and 0.70 and of ${\Delta}/(0.01L)^3=300$. Influence of variation of chine elevation on resistance performance were observed with the test results obtained at normal condition, and at the trimed by the stern by 2% and 4% of $L_{bp}$ at normal condition under same displacement. The hull form characteristics are shown in Table 1, and in Fig. 1, 2, 3, 4 and 5. The test results are shown in Fig 8, 9 and 10 in the form of Cr vs. $V/\sqrt{L}$ curves taking Cp as a parameter for normal condition, trim by the stern in 2% and 4% $L_{bp}$ at normal condition , respectively. Cr vs. $V/\sqrt{L}$ curves taking trim condition as a parameter are also shown in Fig 11, 12 and 13 for Cp=0.60 and 0.70, respectively. The best and the worst trim condition at given $V/\sqrt{L}$ in viewpoint of Cr are plotted for each Cp-value as shown in Fig 14, 15 and 16. From the above results the following conclusions are derived: (1) In general, the resistance performance of the straight-framed V-bottom hull forms are not inferior to those of round hull forms. At a certain range of $V/\sqrt{L}$ the former gives less resistance than the latter. (2) Regarding influences of Cp on Cr, it is observed that, at $V/\sqrt{L}$ less than about 0.925, the greater Cp-value gives the more increment of Cr, and that, at $V/\sqrt{L}$ greater than about 0.925 the smaller Cp-value gives the more increment of Cr. It is also noteworthy that the model of Cp=0.70 has remarkable hump on Cr vs. $V/\sqrt{L}$ curve between $V/\sqrt{L}=0.80$ and 0.90. (3) For higher speed within the test range, the chine elevation having the steeper slope around bow and the easier slope around amidship and stern, refered to watering, give the better results in resistance performance. (4) Assuming the chine elevations adopted for the tested models were not of the best, we would expect further improvement of resistance performance for such form. Hence, a systematic study on chine elevation is very disirable to prepare design data of general purpose for the such hull forms.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.2
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• pp.168-174
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• 2021

According to the World Agricultural Productivity Report, the current annual average growth rate of agriculture is 1.63%, which is lower than 1.73% to support the world's 10 billion people, which is growing by 2050. The demand for food, feed, and bioenergy is not growing enough to continue to meet the demand, and it is predicting a future food shortage. The purpose of this study was to create a regional irrigation control model for the purpose of reducing the production cost of crops, increasing production, and improving quality, and presenting a model that can give advice to farmers who start farming in the region. The irrigation control modeling presented in this study means to represent the change of medium weight·supply liquid·drainage amount due to changes in the root zone environment according to the passage of time and climate in a graph model. For water control modeling, we collected data on the change in the amount of the root zone environment and the weight of the badge·supply amount·drainage amount from March to June in Nonsan, Buyeo, and Yesan regions in Chungnam Province through the measuring device of the Ministry of Environment in the root region. We set up the parameters for derivation and derived an irrigation control model that can confirm the change in weight·supply liquid·drainage amount over time through the parameters.