• Journal of Bio-Environment Control
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• v.17 no.4
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• pp.261-265
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• 2008

This study was carried out to investigate the effects of stem cutting ages and harvest time on the growth and yield of potato 'Dejima' in aeroponics. The stem cuttings were produced from in vitro plantlets and transplanted into an aeroponic system with 20, 30, 40 and 50 day-old stem cuttings (DOS). Tubers were harvested 60, 70, 80 and 90 days after transplanting (DAT) and sorted into following categories: $1{\sim}5$, $5{\sim}10$, $10{\sim}20$, $20{\sim}30$, $30{\sim}40$ and over 40 g. Plant height from the 40 DOS was the highest during the growing periods but no significant difference was observed on 75 DAT. The tuber weight increased until 90 DAT with the greatest weight of tubers in the 20 and 40 DOS. However, there was no significant difference among 20, 30 and 40 DOS in the number and weight of tubers. Harvesting at 80 and 90 DAT increased the number of tubers over 5 g, which are usually considered as appropriate for direct field planting.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.298-298
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• 2013

Finding renewable and clean energy resources is essential research to solve global warming and depletion of fossil fuels in modern society. Recently, complex harvesting of energy from multiple sources is available in our living environments using a single device has become highly desirable, representing a new trend in energy technologies. We report that when simultaneously driving the fusion and composite cells of two or more types, it is possible to make an affect the other cells to obtain a greater synergistic effect. To understand the coupling effect of photovoltaic and piezoelectric device, we fabricate the serially integrated hybrid cell (s-HC) based on organic solar cell (OSC) and piezoelectric nanogenerator (PNG). The size of increased voltage peaks when OSC and PNG are working on is larger than the case when only PNG is working. This voltage difference is the Voc change of OSC, not the voltage change of PNG and current density difference between these two cases is manifested more clearly. When the OSC and PNG are working in s-HC at the same time, piezoelectric potential (VPNG) is generated in ZnO and theoretical total voltage is sum of voltage of an OSC (VOSC) and VPNG. However, electrons from OSC are influenced by piezoelectric potential in ZnO and current loss of OSC in whole circuit decreases. As a result, VOSC increases temporarily. Current shows the similar behavior. PNG acts a resistance in the whole circuit and current loss occurs when the electrons from OSC pass through the PNG. But piezoelectric potential recover current loss and decrease the resistance of PNG. Our PNG can maintain piezoelectric potential when the strain is held owing to the LDH layer while general PNG cannot maintain piezoelectric potential. During the section that strain is held, voltage enhancement effect is maintained and same effect appeared even turn off the light. Actually at this time, electrons in ZnO nanosheets move to LDH and trapped by the positive charges in this layer. After this strain is held, piezoelectric potential of ZnO nanosheets is disappeared but potential difference which is developed by negative charge dominant LDH layer is remained. This potential acts similar role like piezoelectric potential in ZnO. Electrons from the OSC also are influenced by this potential and the more current flows.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.4
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• pp.210-216
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• 2018

This experiment was carried out to study the effect of difference in cold-tolerance and growth characteristics of variety on forage productivity of Italian ryegrass(IRG) in middle region of Korea from 2017 to 2018. Cold-tolerance of IRG was significant different between varieties(p<0.05). Overwinter rate of domestic variety of IRG was higher than that of foreign variety(p<0.05). Among early-maturing varieties, overwinter rate of Kowinearly was highest as 68% that was 33% higher than that of Florida 80. Among middle-maturing varieties, overwinter rate of Kowinmaster was highest as 70% that was 28% higher than that of Tam 90. DM yield of IRG was significant different between varieties(p<0.05). Among early-maturing varieties, DM yield of Kowinearly and Greenfarm 2 was about 3 to 3.5 ton/ha more than that of Florida 80. Among middle-maturing varieties, DM yield of Kowinmaster was about 2ton/ha more than that of winter-hawk or Tam 90. There is a direct correlation between forage productivity and cold-tolerance of IRG variety(p<0.01). These results suggested that choice of early- or middle-maturing variety with cold-tolerant is more important for increasing the forage productivity of IRG If harvesting for roughage have to be finished in the middle ten days of May in middle region of Korea.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.1
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• pp.17-23
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• 2019

This experiment was carried out to evaluate the characteristic and productivity of forage corn varieties sown at the last ten days of May at Cheonan of Korea on 2017 and 2018. Forage corn varieties sown on 24th May 2017 and $25^{th}$ May 2018 were emerged in 5th and 1st June, respectively. Silking date of forage corns was different among varieties(p<0.05). Stem length of forage corns was not different among the varieties, except Kwangpyeongok(KPA) and Nero IT. Stem diameter of forage corns was not different amaong the varieties. Outbreak rate of black streaked dwarf virus was lower than 3% in all varieties. Total digestible nutrient(TDN) yield was different among corn varieties(p<0.05), which was higher in P32P75, followed by P2088, P31N27, and KPA. The TDN yield of varieties had direct correlation with stem length, stem diameter and ear yield, respectively(p<0.01). Average of TDN in all varieties was 69.8%. These results suggested that forage corn variety with late-seeding adaptability is more important for increasing the productivity of forage corn If harvesting of winter forage crops have to be finished in the middle ten days of May in middle region of Korea.

• Korean Journal of Agricultural Science
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• v.49 no.4
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• pp.677-696
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• 2022

Development of radish collectors may enhance radish production and promote upland crop mechanization in the Republic of Korea. Theoretical analysis of power is crucial to ensure the optimum design of agricultural machinery. The aim of the present study is to analyze theoretically the power requirement of a tractor-mounted radish collector under development and to propose design guidelines. The important components of the radish collector were belt-type conveyors, three hydraulic motors, and a direct current (DC) winch motor to operate the total radish collecting process. Theoretical equations were used to calculate the hydraulic motor's power, winch motor power, and draft power at loaded and unloaded conditions. A variety of tractors (44 - 74 kW) and different soil characteristics (hard, firm, tilted, and sandy) were considered to investigate the appropriate drawbar power. Variations of the power requirement of the tractor-mounted radish collector were observed due to modifications of the design parameters. The required hydraulic power of the stem cutting conveyor, stem cutting blade, and transfer conveyor of the radish collector were 0.23 and 0.24, 0.18 and 0.19, and 0.19 and 0.22 kW under unloaded and loaded conditions, respectively. The maximum draft power was calculated as 0.89, 1.07, 1.25, and 1.61 kW at a 30° tilted angle for hard, firm, tilted, and sandy soil, respectively. The calculation showed 2.07 kW DC power was required for unfolding or folding the stem-cutting conveyor. A maximum power of 4.78 kW was prescribed for conducting the whole process of the tractor-mounted radish collector. The analysis of power introduced in this study will be helpful to select the appropriate design parameters for the successful development of a tractor-mounted radish collector.

• Korean Journal of Environment and Ecology
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• v.30 no.3
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• pp.291-307
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• 2016

Evaluation of the extinction risk of endangered plants at international, national as well as at regional levels is essential to the implementation of plans for direct conservation activities. Reports indicate that 34 endangered plants are distributed in the middle eastern area of Korea. For each endangered plant, we investigated the sites, area of extents, population size, and factors that affect population extinction. We assessed risk factors based on 10 evaluation criteria including the results from the investigation and the life traits each endangered plant has. As a result of evaluating the risk factors, these 34 endangered plants are classified into 3 groups: the first category comprises 12 endangered plants that require active and urgent conservation of habitats due to multiple risk factors; the second group has 16 endangered plants that should be able to persist with the removal of a few direct risk factors; the third category has 6 endangered plants that can persist with minimal management due to comparatively large distributed area and numerous individuals. It was found that most major risk factors in the population of endangered plants are caused by disruption of habitats and population extinction due to the increase of human habitation in the concerned areas, development and illegal harvesting. Futhermore, ecological collapse from decreasing habitats and malfunctioning mechanism of extinction and regeneration due to the changes of vegetational environment can be the other causes. From the area of the present investigations, we selected 5 regions according to the number of species and the frequency of appearance and importance of conservation measures. Also, we suggested a conservation strategy according to the regional characteristics. We suggest that the method for evaluating extinction risk of endangered plants includes distributional data and life traits of species. In addition, we underscore the necessity for understanding population dynamics and ecological niche of the each target species.

• Korean Journal of Weed Science
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• v.11 no.1
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• pp.32-49
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• 1991

Residual period and carry-over effect of some herbicides were determined using a bioassay method in five winter crops (chinese cabbage, radish, spinach, onion and garlic). The effects were measured at regular time intervals after applling different rates of the herbicides. There were no great differences in residual period and carry-over injury between the soils and kinds of crops used. However, the residual period varied with the herbicides studied and the carry-over injury was rate of the herbicide application, sampling depth of soil, and kind and seeding date of the test plant. When the residual herbicides were applied, the carry-over injury could be minimized by selecting tolerant crops, delaying seeding of the crops after application of the herbicides, and regulating the cultivation depth. Herbicides which showed no residual effect by the end of the cropping period (200-240 days for winter crops) and no carry-over effect were alachlor, trifluralin, ethalfluralin and prometryn. When pendimethalin, metolachlor, linuron and methabenthiazuron were applied at the recommended rate or less, there was no carry-over injury at harvesting time. With doubling the recommended rate, however, the carry-over effect was found in sensitive crops. Napropamide applied in winter crops at rate of 150-300g a.i./10a brought about carry-over injury for such Gramineae as Italian ryegrass, direct-seeded rice and barley, whereas the injury was not found in lowland-transplanted rice, Cruciferae, Cucurbitaceae and Solanaceae. Long residual herbicide nitralin applied at the rate of 75g a.i./10a caused the carry-over injury for Italian ryegrass, direct-seeded rice, baley and lowland-transplanted rice at 275 days in winter crops. In addition, a slight injury occurred in sesame, perilla and spinach, However, there was no injury for Cruciferae, Cucurbitaceae and Solanaceae.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.50-57
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• 1985

An attempt was made to determine the optimum levels of sewage sludge application for seogwangbyeo in the farmer's field. 1. Optimum amount of sewage slude application was 338kg/11a at the fertilizer (N-P-K) level of 15-10-10kg/10a, 430kg/10a at that of 7.5-10-10kg/10a and 544kg/10a at no fertilizer. 2. Number of tillers during all growing period were increased with amounts of sewage sludge and/or chemical fertilizers. 3. Panicles per hill was increased but percent ripeness was decreased with the application of increasing level of sewage sludge and/or chemical fertilizer. In particular, the decrease of ripeness among yield-related components sotood out as an important one to be solved for higher yield. 3. Panicles per hill was increased but percent ripeness was decreased with the application of increasing level of sewage sludge and/or chemical fertilizer. In particular, the decrease of ripeness among yield-related components stood out as an important one to be solved for higher yield. 4. Ripeness was remarkably decreased in high nitrogen content of soil and rice plant under heavy amounts of sewage sludge and/or chemical fertilizer. 5. Ripeness that had direct effect on yield showed significantly possitive correlation with the content of $SiO_2$ and $SiO_2/N$ in rice plant from 25 days after transolanting to harvesting stage. 6. Maximumutillzation of nitrogen and its production efficiency of absorbed nitrogen in sewage sludge were 16.6% and 31.9kg (Yield/kg, N) at the level 15-10-10kg/10a as fertilizer with amounts of sewage sludge application, and 19.0% and 31.8kg (yield/kg, N) at sewage sludge application without fertilizer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.4
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• pp.398-410
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• 1982

Summer crops grown in uplands are greatly diversified and show a large variation in difference with year and location in Korea. The principal factor for the variation is weather, in which precipitation and temperature play a leading role and such a weather factors as wind, sun lights also influence production of the summer crops. Since artificial control of weather conditions as a main stress factor for crop production is almost impossible, it must be minimized only by an improvement of cultivation techniques and crop improvement. Precipitation plays a role as one of the most important factor for production of the summer crops and it is considered in two aspects, drought and excess moisture. This country, which belongs to monsoon territory, necessarily encounter one of this stress almost every year, even though the level is different. Therefore, the facilities for both drought and excess moisture are required, but actually it is not easy to complete for them. On this account, crops tolerant to drought, excess moisture and pests should be considered for establishing summer crops. For the districts damaged habitually every season, adequate crops should be cultured and appropriate method of planting, drainage and weed control should be applied diversely. Injuries by temperature is mainly attributed to lower temperature particularly in late fall and early spring, although higher temperature often causes some damages depending upon the kind of crops. Sometimes, lower temperature in summer season playa critical role for yield reduction in the summer crops. However, certain crops are prevented to some extent from this kind of stress by improving varieties tolerant to cold, hot weather or early maturing varieties. As is often the case, control of planting time or harvesting is able to be a good management for escaping the stress. Lodging, plant diseases and pests are considered as a direct or indirect damage due to weather stress, but these are characters able to be overcome by means of crop improvement and also controlled by other suitable methods. In addition, polytical supports capable of improving constitution of agriculture into modern industry is urgently required by programming of data for the damages, establishment of damage forecasting and compensation system.

• Archives of Reconstructive Microsurgery
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• v.5 no.1
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• pp.24-34
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• 1996

There are many kinds of free flaps for management of extensive soft tissue defect of extremities in orthopaedic field. Free vascularized scapular flap is one of the most useful and relatively easy to application. This flap has been utilize clinically from early eighties by many microsurgical pioneers. Authors performed 102 cases of this flap from 1984 to 1995. We have to consider about the surgical anatomy of the flap, technique of the donor harvesting procedures, vascular varieties and anatomical abnormalities and success rate and the weak points of the procedure. This flap nourished by cutaneous branches from circumflex scapular vessels emerges from the lateral aspect of the subscapular artery 2.5-5cm from its lateral origin passing through the triangular space(bounded by subscapularis, teres minor, teres major, long head of triceps). The terminal cutaneous branch runs posteriorly around the lateral border of the scapular and divided into two major branches, those transeverse horizontally and obliquely to the fascial plane of overlying skin of the scapular body. We can utilize these arteries for scapular and parascapular flap. The vascular pedicle ranged from 5 to 10 cm long depends on the dissection, usually two venae comitantes accompanied circumflex scapular artery and its major branches. The diameter of the circumflex scapular artery is more than 1mm in adult, rare vascular variation. Surgical techniques : The scapular flap can be dissected conveniently with prone or lateral decubitus position, prone position is more easier in my experience. There are two kinds of surgical approaches, most of the surgeon prefer elevation of the flap from its outer border towards its base which known easier and quicker, but I prefer elevation of the flap from its outer border because of the lowering the possibilities of damage to vasculature in the flap itself which runs just underneath the subcutaneous tissue of the flap and provide more quicker elevation of the flap with blunt finger dissection after secure pedicle dissection and confirmed the course from the base of the pedicle. There are minimal donor site morbidity with direct skin closure if the flap size is not so larger than 10cm width. This flap has versatility in the design of the flap shape and size, if we need more longer and larger one, we can use parascapular flap or both. Even more, the flap can be used with latissimus dorsi musculocutaneous flap and serratus anterior flap which have common vascular pedicle from subscapular artery, some instance can combined with osteocutaneous flap if we include the lateral border of the scapular bone or parts of the ribs with serratus anterior. The most important shortcoming of the scapular free flap is non sensating, there are no reasonable sensory nerves to the flap to anastomose with recipient site nerve. Results : Among our 102 cases, overall success rate was 89%, most of the causes of the failure was recipient site vascular problems such as damaged recipient arterial conditions, and there were two cases of vascular anomalies in our series. Patients ages from 3 years old to 62 years old. Six cases of combined flap with latissimus dorsi, 4 cases of osteocutaneous flap for bone reconstruction, 62 parascapular flap was performed - we prefer parascapular flap to scapular. Statistical analysis of the size of the flap has less meaningful because of the flap has great versatility in size. In the length of the pedicle depends on the recipient site condition, we can adjust the pedicle length. The longest vascular pedicle was 14 cm in length from the axillary artery to the enter point cutaneous tissue. In conclusion, scapular free flap is one of the most useful modalities to manage the large intractable soft tissue defect. It has almost constant vascular pedicle with rare anatomical variation, easy to dissect great versatility in size and shape, low donor morbidity, thin and hairless skin.