• Korean Journal of Plant Resources
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• v.9 no.2
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• pp.151-155
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• 1996

For improvement germination rate of Cirsium setidens, wet seeds were storaged for 20 to 80 days at $4^{\circ}C$ and germinated at $18^{\circ}C$ in the dark or light condition. To assess the effects of shading and plant age on the growth, fresh yield and seed yield under rain shelter in highland at altitude of 800m above sea level, seeds were sown in an open field in late september,1990. In early May the next the seedlings were transplanted for vegetatable and seed production in the plastic houses for rain shelter. They were grown from 1991 to 1993 in the houses covered with the shading nets ranging from 0 to 70% for vegetable production and 0 to 50% for seed production. Germination rate inceased as the storage period lengthened, and the rate came to $60\sim80%$ at 60days after germination. It was more effective in lighting than in darkness. For vegetable production, the shading net treatments showed more values in almost the characters checked at the third year than the non-shading treatment. No. of stem, no, of leaves, stem length and degree of softening were no different between shading net treatments, but the other characters were significantly different. Ratio of survival, density of chlorophyll and ratio of dry matter of plants were highest in the plots of 50%, 70%, and 30% of shading, respectively. The highest fresh yield was recorded from 2-year plants, 70% of shading from them showed the greatest yield. The highest seed yields were produced 2-year-old plants of non-shading plot. For seed production, the non-shading treatment is best, and the highest seed yields were obtained in both the second and third years.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.371-377
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• 2007

The passive integrated transponder (PIT) telemetry is a useful method for investigating fish population dynamics, community structure and migration. It can be applied for small fishes (TL<100 mm) because of its tiny size and light weight. The survival rate of PIT tag was investigated on 4 small size cyprindae fish species, Carassius gibelio langsdorfi (n=34, standard length; $91.9{\pm}0.9mm$, body weight; $21.2{\pm}0.9g$), Hypophthalmichthys molitrix (n=16, SL; $75.1{\pm}0.9mm$, BW; $6.0{\pm}0.2g$), Pseudorasbora parva (n=30, SL; $51.4{\pm}1.1mm$, BW; $2.7{\pm}0.2g$) and Phoxinus phoxinus (n=37, SL; $70.6{\pm}1.4mm$, BW; $8.2{\pm}0.5g$) under age 1 for applicability and effectiveness. We used three type tags including a small (length 11.0 mm, diameter 2.1 mm, weight 0.088 g), middle (20 mm, 3.5 mm, 0.102 g), large (30 mm, 3.5 mm, 0.298 g) size. After 30 days of tag insertion, survival rate of 117 individuals were 58.1% (large tag, 50.0%; middle tag, 57.5%; small tag, 61.4%). Survival rates varied between three types of tags because the abdominal cavity of each individual was different size. The death was due to surgical damage. If we apply tagging systems on field research of the Korean freshwater fish, the PIT tag will be effective method for analyzing fish ecology.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.1
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• pp.1-10
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• 2018

Recently, there has been rapid development in the field of flexible electronic devices, such as organic light emitting diodes (OLEDs), organic solar cells and flexible sensors. Encapsulation process is added to protect the flexible electronic devices from exposure to oxygen and moisture in the air. Using numerical simulation, we investigated the effects of the encapsulation layer on mechanical stability of the silicon chip, especially the fracture performance of center crack in multi-layer package for various loading condition. The multi-layer package is categorized in two type - a wide chip model in which the chip has a large width and encapsulation layer covers only the chip, and a narrow chip model in which the chip covers both the substrate and the chip with smaller width than the substrate. In the wide chip model where the external load acts directly on the chip, the encapsulation layer with high stiffness enhanced the crack resistance of the film chip as the thickness of the encapsulation layer increased regardless of loading conditions. In contrast, the encapsulation layer with high stiffness reduced the crack resistance of the film chip in the narrow chip model for the case of external tensile strain loading. This is because the external load is transferred to the chip through the encapsulation layer and the small load acts on the chip for the weak encapsulation layer in the narrow chip model. When the bending moment acts on the narrow model, thin encapsulation layer and thick encapsulation layer show the opposite results since the neutral axis is moving toward the chip with a crack and load acting on chip decreases consequently as the thickness of encapsulation layer increases. The present study is expected to provide practical design guidance to enhance the durability and fracture performance of the silicon chip in the multilayer package with encapsulation layer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.6
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• pp.327-340
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• 2017

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.137-142
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• 1998

Assessment of N release pattern from hairy vetch (Vicia villosa Roth) residue is an important step for the efficient use of the residue as a green manure and the specific management strategy development. Objective of this research was to determine the changes of chemical composition, especially in light of the N release, when the residues of hairy vetch were applied in the soil. hairy vetch was harvested at different growth stages (April 23, May 9, and May 28) and the residues were encapsulated in the nylon mesh (1 mm) bag. The bags were placed on the surface of no-tillage plots and buried at 15cm in depth in conventional tillage plots of the corn field in early June. The bags were removed for measurements of dry matter and N content at 1, 2, 3. 5, 8 and 12 weeks after placement. Dry matter and N content of hairy vetch were higher when harvested closer to maturity, as also found in C/N ratio, cellulose and hemicellulose contents. The rate of N releases from hairy vetch residue under conventional tillage condition was greater than that under no-tillage condition. Percentages of N remaining in residue over the initial N contents under conventional tillage condition were in average 40, 23, and 15% for 1, 2, and 3 weeks after placement of mesh bag, respectively, compared with respective values of 71, 31, and 21% under no-tillage condition. The rate of N release was slower as the harvest time was closer to maturity of hairy vetch under both tillage conditions. Most of N in residue was released within 3 and 5 weeks, under conventional and no-tillage conditions, respectively. Results indicated that amounts of N released from hairy vetch residue were more closely related to the variability of N contents in residue due to the harvest time than changes of chemical composition of plant or soil management.

• Korean Journal of Environmental Agriculture
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• v.32 no.1
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• pp.42-47
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• 2013

BACKGROUND: As improved LEDs (Light Emitting Diode) industry and decreased the price of LEDs in Korea, some farmers try to using the RED LEDs in green house and open field to increase the production of crop under bad weather condition. The aim of this study is to find out the effect of RED and FAR-RED LEDs lighting on the fruit quality of twelve-year old 'Hongro'/M.26 apple during night after sunset. METHODS AND RESULTS: FAR-RED (730nm, 2 and 4 hour) and RED (620nm, 2 and 4 hour) with 20 LED/PCB were treated in orchard for 16 weeks from June 10 to October 10 in 2009 and 2010 with control as an comparison. In our experiments, leaf weight was significantly higher in RED LEDs than control, tended to be decreased as times of FAR-RED lighting increased. Fruit weight was increased more in RED LEDs than control in 2009 and 2010, but decreased in FAR-RED lighting compared to control in 2010. Firmness and Hunter's a value of fruit were increased in FAR-RED lighting with 2 and 4 h than control. Soluble solid contents were higher in 2 h RED and 2, 4 h FAR-RED LEDs compared to control in 2009, there was no significant difference in 2010. Acid contents were no difference among the treatments. CONCLUSION(S): In our results, we found that RED LEDs was more helpful to increase the fruit weight and FAR-RED LEDs promote to be higher hunter a value of fruit skin. So, we thought that it is necessary to more study if mixed of RED and FAR-RED lighting is more helpful to promote fruit quality of 'Hongro' apple than single lighting of RED or FAR-RED LEDs respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.352-361
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• 1990

The reducing effect of wind injury was investigated using several wind-break nets in Youngdeok province where cold-wind damage is often occurred during rice growing season. The white-head damage of rice have been often occurred by typhoon during the period between August 15 to September 10 in the cold wind area of the eastern coastal during the last 11 years (1979-1989). This may suggest that the critical period for heading will be by August 15 in the regions. High evaporation coefficient, more than 250 due to typhoon passage over the regions resulted high injury of white head. Generally, the wind injury have been caused by warm and dry westerlies through Fohn apperance in Taebaeg mountains and by cool-humid wind which blows from coast to inland. The frequency of occurrence of the two types of typhoons were 25, 20%, respectively during rice cultivation. The instalation of wind-break net significantly reduced the wind blowing speed, depending on the net mesher with the higher effect in dence net. The distances between the net and cropping area also affect the wind speed: 23% reduction at 1m distance. 34% at 10m and 28% at 20m, respectively. The reducing effect was also observed even at 10 times height of the wind-break net. The instalation of wind-break net gave several effects on climate factor, showing that temperature increased by 0.8$^{\circ}C$(maximum), 0.7$^{\circ}C$(minimum), 0.6$^{\circ}C$(average) : water temperatures increased by 0.5$^{\circ}C$(maximum), 0.6$^{\circ}C$(minimum), 0.5$^{\circ}C$(average) : soil temperature increased 0.4$^{\circ}C$. The earlier heading and increasing growth rate, use of light, culm length, panicle number per hill, spikelet number per panicle, fertility and 1,000 grain weight were observed in the fields with the wind-break nets resulting in 10-15% increase in rice yield using 0.5${\times}$0.5cm nets. The increasing seedlings per hill gave higher grain yield by 13% in the cold wind damage regions of eastern coastals. and the wind-break was more significant in the field without the wind-break net. Wind injury of rice plant in the cold wind regions of eastern coastals in korea could be reduced by selection of tolerant varieties to wind injury, adjustment of transplanting time, and establishment of wind-break nets.