• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.3
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• pp.497-504
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• 2019

We fabricated $HfO_2$ thin films using RF magnetron sputtering method, and investigated structural and optical properties of $HfO_2$ thin films with RTA temperatures in $N_2$ ambient. $HfO_2$ thin films exhibited polycrystalline structure regardless of annealing process, FWHM of M (-111) showed reduction trend. The surface roughness showed the smallest of 3.454 nm at a annealing temperature of $600^{\circ}C$ in result of AFM. All $HfO_2$ thin films showed the transmittance of about 80% in visible light range. By fitting the refractive index from the transmittance and reflectance to the Sellmeir dispersion relation, we can predict the refractive index of the $HfO_2$ thin film according to the wavelength. The $HfO_2$ thin film annealed at $600^{\circ}C$ exhibited a high refractive index of 2.0223 (${\lambda}=632nm$) and an excellent packing factor of 0.963.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.1-21
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• 2021

Panax species have gained numerous attentions because of their various biological effects on cardiovascular, kidney, reproductive diseases known for a long time. Recently, advanced analytical methods including thin layer chromatography, high-performance thin layer chromatography, gas chromatography, high-performance liquid chromatography, ultra-high performance liquid chromatography with tandem ultraviolet, diode array detector, evaporative light scattering detector, and mass detector, two-dimensional high-performance liquid chromatography, high speed counter-current chromatography, high speed centrifugal partition chromatography, micellar electrokinetic chromatography, high-performance anion-exchange chromatography, ambient ionization mass spectrometry, molecularly imprinted polymer, enzyme immunoassay, 1H-NMR, and infrared spectroscopy have been used to identify and evaluate chemical constituents in Panax species. Moreover, Soxhlet extraction, heat reflux extraction, ultrasonic extraction, solid phase extraction, microwave-assisted extraction, pressurized liquid extraction, enzyme-assisted extraction, acceleration solvent extraction, matrix solid phase dispersion extraction, and pulsed electric field are discussed. In this review, a total of 219 articles published from 1980 to 2018 are investigated. Panax species including P. notoginseng, P. quinquefolius, sand P. ginseng in the raw and processed forms from different parts, geographical origins, and growing times are studied. Furthermore, the potential biomarkers are screened through the previous articles. It is expected that the review can provide a fundamental for further studies.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.6
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• pp.787-792
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• 2022

In winter, the excessive use of deicing salt deteriorates concrete pavement durability. To reduce the amount of deicing salt used, phase-change materials (PCMs) potentially offer an alternative way to melt snow through their latent heat storage characteristics. In this research, thermal energy storage concrete was developed by using PCM-impregnated expanded clay as 50 % replacement to normal aggregate by volume. In addition, to improve the thermal efficiency of PCM lightweight aggregate (PCM-LWA)-incorporated concrete, multi-walled carbon nanotubes (MWCNTs) were incorporated in proportions of 0.10 %, 0.15 %, and 0.20 % by binder weight. Compressive strength testing and programmed thermal cycling were performed to evaluate the mechanical and thermal responses of the PCM-LWA concrete. Results showed a significant strength reduction of 54 % due to the PCM-LWA; however, the thermal performance of the PCM-LWA concrete was greatly improved with the addition of MWCNTs. Thermal test results showed that 0.10 % MWCNT-incorporated concrete had high thermal fatigue resistance as well as uniform heat flow, whereas specimens with 0.15 % and 0.20 % MWCNT content had a reduced thermal response due to supercooling when the ambient temperature was varied between -5℃ and 10℃.

• Journal of Bio-Environment Control
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• v.21 no.3
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• pp.271-275
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• 2012

The average annual and winter ambient air temperatures in Korea have risen by $0.7^{\circ}C$ and $1.4^{\circ}C$, respectively, during the last 30 years. The continuous rise in temperature presents a challenge in growing certain horticultural crops. Chinese cabbage, one most important cool season crop, may well be used as a model to study the influence of climate change on plant growth, because it is more adversely affected by elevated temperatures than warm season crops. This study examined the influence of transplanting time, nitrogen fertilizer level and climate parameters, including air temperature and growing degree days (GDD), on the performance of a Chinese cabbage cultivar (Chunkwang) during the spring growing season to estimate crop yield under the unfavorable environmental conditions. The chinese cabbage plants were transplanted from Apr. 8 to May 13, 2011 when 3~4 leaves were occurred, at internals of 7 days and cultivated with 3 levels of nitrogen fertilization. The data from plants transplanted on Apr. 22 and 29, 2012 were used for the prediction of yield as affected by planting date and nitrogen fertilization for spring production. In our study, plant dry weight was higher when the seedlings were transplanted on 15th (168 g) than on 22nd (139 g) of April. There was no significant difference in the yield when plants were grown with different levels of nitrogen fertilizer. The values of correlation coefficient ($R^2$) between GDD and number of leaves, and between GDD and dry weight of the above-ground plant parts were 0.9818 and 0.9584, respectively. Nitrogen fertilizer did not provide a good correlation with the plant growth. Results of this study suggest that the GDD values can be used as a good indicator in predicting the top biomass yield of Chinese cabbage.

• Korean Journal of Ecology and Environment
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• v.41 no.3
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• pp.348-359
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• 2008

The objectives of the study were to elucidate functional modifications in relation to hydrological, physico-chemical and ecological aspects in Daechung Reservoir by the upper dam constructions of Youngdam Reservoir and analyze temporal and spatial dynamic patterns using trophic parameters of TN, TP, chlorophyll (CHL), and Secchi depth (SD). Hydrological data such as inflow, precipitation, and water levels before (BDC, 1995$\sim$2000) and after (ADC, 2001$\sim$2006) the dam construction showed that precipitation had greater correlations with inflow volume in the BDC (r=0.964, p=0.002) than in the ADC (r=0.857, p=0.029). This outcome indicates that the upper dam construction influenced the inflow and water level of Daechung Reservoir. One of the greatest changes after the dam construction was decreases of nutrient contents (TN, TP) and increases of algal biomass (as CHL) as the water residence time increases. Values of CHL had greater relations with TP in the ADC (r=0.412, p<0.001) than the BDC (r=0.249, p<0.001), indicating that CHL had greater response at a given phosphorus in the ADC. Thus, algal yield at a given TP (CHL : TP ratios) increased in the ADC, resulting in a greater CHL-TP relations. Long-term interannual TP, TN, SD, and CHL showed greater variations in the riverine zone (RZ) than any other transition (TZ) and lacustrine zones (LZ). This phenomenon was mainly attributed to rapid hydrological response in the riverine zone (RZ) to flow reductions (short water residence time) from the upper dam, resulting in ambient contents of nutrients and light regime along with functional relations of CHL-TP.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1615-1634
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• 2004

A review was undertaken to obtain information on the sustainability of pig free-range production systems including the management, performance and health of pigs in the system. Modern outdoor rearing systems requires simple portable and flexible housing with low cost fencing. Local pig breeds and outdoor-adapted breeds for certain environment are generally more suitable for free-range systems. Free-range farms should be located in a low rainfall area and paddocks should be relatively flat, with light topsoil overlying free-draining subsoil with the absence of sharp stones that can cause foot damage. Huts or shelters are crucial for protecting pigs from direct sun burn and heat stress, especially when shade from trees and other facilities is not available. Pigs commonly graze on strip pastures and are rotated between paddocks. The zones of thermal comfort for the sow and piglet differ markedly; between 12-22$^{\circ}C$ for the sow and 30-37$^{\circ}C$ for piglets. Offering wallows for free-range pigs meets their behavioural requirements, and also overcomes the effects of high ambient temperatures on feed intake. Pigs can increase their evaporative heat loss via an increase in the proportion of wet skin by using a wallow, or through water drips and spray. Mud from wallows can also coat the skin of pigs, preventing sunburn. Under grazing conditions, it is difficult to control the fibre intake of pigs although a high energy, low fibre diet can be used. In some countries outdoor sows are fitted with nose rings to prevent them from uprooting the grass. This reduces nutrient leaching of the land due to less rooting. In general, free-range pigs have a higher mortality compared to intensively housed pigs. Many factors can contribute to the death of the piglet including crushing, disease, heat stress and poor nutrition. With successful management, free-range pigs can have similar production to door pigs, although the growth rate of the litters is affected by season. Piglets grow quicker indoors during the cold season compared to outdoor systems. Pigs reared outdoors show calmer behaviour. Aggressive interactions during feeding are lower compared to indoor pigs while outdoor sows are more active than indoor sows. Outdoor pigs have a higher parasite burden, which increases the nutrient requirement for maintenance and reduces their feed utilization efficiency. Parasite infections in free-range pigs also risks the image of free-range pork as a clean and safe product. Diseases can be controlled to a certain degree by grazing management. Frequent rotation is required although most farmers are keeping their pigs for a longer period before rotating. The concept of using pasture species to minimise nematode infections in grazing pigs looks promising. Plants that can be grown locally and used as part of the normal feeding regime are most likely to be acceptable to farmers, particularly organic farmers. However, one of the key concerns from the public for free-range pig production system is the impact on the environment. In the past, the pigs were held in the same paddock at a high stocking rate, which resulted in damage to the vegetation, nutrient loading in the soil, nitrate leaching and gas emission. To avoid this, outdoor pigs should be integrated in the cropping pasture system, the stock should be mobile and stocking rate related to the amount of feed given to the animals.

• Journal of Bio-Environment Control
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• v.18 no.1
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• pp.15-22
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• 2009

Adequate environment conditions with growth stage of potato were decided in a photoautotrophic micropropagation system using models. Total 20 day-period of growth were divided into three growth periods such as 6 (stage 1), 7(stage 2), and 7(stage 3) days. At the 1st stage, no significant differences were observed in the growth of potato plantlets at various photosynthetic photon flux density (PPFD) and $CO_2$ conditions. Considering damaged leaves, $80\;mmol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and ambient $CO_2$ level were adequate in this stage. At the 2nd stage, significant differences were partly observed in several growth characteristics including dry weight. Based on the dry matter model, over $240\;mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD was too high to cultivate potato plantlets at this stage due to the occurrence of damaged leaves. Considering both plant growth and energy efficiency, $160\;mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and $700\;mol{\cdot}mol^{-1}\;CO_2$ were selected for the adequate combination. At the 3rd stage, the biomass accumulation was significantly induced in potato plantlets under higher levels of PPFD and $CO_2$ concentration as suggested by increased fresh and dry weights. However, we could not find the saturated point with regard to dry matter due to continuous increase of dry mater even under maximum PPFD ($320\;mmol{\cdot}m^{-2}{\cdot}s^{-1})$. Thus, $320\;mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and $1800\;mol{\cdot}mol^{-1}\;CO_2$ were considered as the best choice at final stage in this study. In conclusion, even though the growth period of micropropagated potato plantlets was quite a short, favorable environmental conditions required at each growth stage were different. This technique could improve the growth of micropropagated plantlets compared to the conventional micropropagation and apply to other agriculturally important crops as well as potato in the future.

• Korean Journal of Ecology and Environment
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• v.49 no.1
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• pp.11-21
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• 2016

Cymbidium kanran Makino is being threatened in its own habitats due illegal collecting and habitat changes by vegetation growth along historical landuse change. In this study, we established habitat restoration model for conservation of C. kanran based on ecological diagnosis. Through exploration to Jeju Island in 2014 and 2015, we identified 27 unknown habitats of C. kanran and in there, abiotic variables and vegetation structure and composition were quantified. Altitudinal distribution of C. kanran was between 200 m~700 m a.s.l. and compared to distribution in 2004, Area of Occupation (AOO) decreased at 82%. Specific habitat affinity was not observed by evenly found in mountain slope and valley and summergreen and evergreen broadleaved forests, but likely more abundant in valley habitats with higher soil and ambient moisture. Total of 96 individual of C. kanran was observed with an average density of $942.6individuals\;ha^{-1}$. The plants showed relatively short leaf length (average=$10.7cm{\pm}1.1cm$) and small number of pseudo bulbs ($1.2{\pm}0.2$). Flowering and fruiting individuals were not observed in field. C. kanran was classified into endangered plant species as CR (Critically Endangered) category by IUCN criteria. Phenotypic plasticity of C. kanran was likely support to sustain in more shaded habitat environment and recent habatat changes to closed canopy and low light availability may exhibit negatively effects to C. kanran's life history. Restoring C. kanran habitat should create open environment as grassland and low woody species density.

• Journal of Bio-Environment Control
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• v.15 no.2
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• pp.125-137
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• 2006

Pleurotus eryngii is one of the most promising mushrooms produced on the domestic farms. The quality as well as quantity of Eryngii is sensitively affected by micro climate factors such as temperature, relative humidity, $CO_2$ concentration, and light intensity. To safely produce high-quality Eryngii all the yew round, it is required that the environmental factors be carefully controlled by well designed structures equipped with various facilities and control systems. At the commercial mushroom cultivation houses of permanent frame type (A, B), this study was carried out to find out reasonable range of each environmental factor and yield together with economic and safe structures influencing on the optimal productivity of Eryngii. This experiment was conducted for about two-year ken Nov. 2003 to Dec. 2005 in cultivation house. Ambient temperature during the experiment period was not predominantly different from that of a normal year. The capacity of the hot water boiler and the piping systems were not enough. Because the capacity of electric heater and air circulation were not enough, air temperatures in cultivation house before improvement of system were maintained somewhat lower than setting temperature, and maximum air temperature difference between the upper and lower growth stage during a heating time period was about 5.1. But the air temperatures after system improvement were maintained within the limits range of setting temperature without happening stagnant of air. Air temperature distribution was generally distributed uniform. Relative humidity in cultivation house before , improvement was widely ranged about $44{\sim}100%$. But as the relative humidity after improvement was ranged approximately $80{\sim}100%$, it was maintained within the range of relative humidity recommended. And $CO_2$ concentration was maintained about $400{\sim}3,300mg{\cdot}L^{-1}$ range. The illuminance in cultivation house was widely distributed in accordance with position, and it was maintained lower than the recommended illuminance range $100{\sim}200lx$. The acidity of midium was some lower range than the recommend acidity range of pH $5.5{\sim}6.5$. The yield was relatively ununiform. In case of bottle capacity of 1,300cc, the mushroom of the lowest grade was less than 3%. The consumption electric energy was quite different according to the cultivation season. The electric energy consumed during heating season was much more than that of cooling season.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.101-108
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• 1993

$TiO_{2}$/Se : Te heterojunction for color sensor has been fabricated by RF reactive sputtering and thermal evaporation methods onto glass substrate. The optimum deposition condition of $TiO_{2}$ films was such that RF power was 120 W, substrate temperature was $100^{\circ}C$, oxygen concentration was 50%, working pressure was 50 mTorr for the $TiO_{2}$ film thickness of $1000{\AA}$. In this case, the optical transmittance of $TiO_{2}$ film at 550 nm-wavelength was 85%, resistivity was $2{\times}10^9{\Omega}{\cdot}cm$, refractive index was 2.3, and optical bandgap was 3.58 eV. The composition ratio of 0 to Ti by AES analysis was 1.7. When $TiO_{2}$ films were annealed at $400^{\circ}C$ for 30 min. in $O_{2}$ ambient, the optical transmittance of $TiO_{2}$ films at the wavelength range of $300{\sim}580$ nm was improved from 0 to 25%. When Se : Te films were annealed at $190^{\circ}C$ for 1 min., photosensitivity under illumination of 1000 lux was 0.75. The optical bandgap of Se : Te films was 1.7 eV. The structures of Se : Te films were the hexagonal with (100) and (110) orientation. The spectral response of a-Se was improved by the addition of Te, especially in the long wavelength region. The $TiO_{2}$/Se : Te heterojunction showed wide spectral response, and more improved one than that of a-Si film in the blue light region.