• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.11a
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• pp.3-19
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• 2001

Where temperature permits plant growth, the existence of plants is controlled chiefly by the water availability. Without water, plants cannot grow, and man and animals cannot survive. With too much water, plant growth is also rather limited due partly to oxygen deficit in root zone (Ro et al., 1995). The objective of this seminar is to discuss the most important aspects of water management in relation to crop production and environmental conservation. (omitted)

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.51-51
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• 2009

In order to understand the properties of high heat input welds made by electro gas welding, two kinds of low temperature steel were welded. Welding heat inputs were controlled by width of root gap and ranged from 118 to 143kJ/cm. Chemical composition and micro-structural analysis were performed. To understand low temperature impact properties, Charpy impact test was conducted at several temperatures. The results were summarized as follows; 1) Grain size of weld metal and heat affected zone was increased with an increase in welding heat input. 2) Impact test values at fusion line were severely fluctuated regardless of base metals, showing enormous difference among the values at the same test temperature.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.243-251
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• 2015

This study aimed to determine the effects of root zone cooling using air duct on air temperature distribution and root zone and leaf temperatures of sweet pepper (Capsicum annum L. 'Veyron') grown on coir substrate hydroponic system in a greenhouse. When the air duct was laid at the passage adjacent the slab, the direction of air blowing was upstream at $45^{\circ}$. The cooling temperature was set at $20^{\circ}C$ for day and $18^{\circ}C$ for night. For cooing timing treatments, the cooling air was applied at all day (All-day), only night time (5 p.m. to 1 a.m.; Night), or no cooling (Control). The air temperature inside the greenhouse at a height of 40 and 80cm above the floor, and substrate and leaf temperatures, fruit characteristics, and fruit ratio were measured. Under the All-day treatment, the air temperature was decreased about $4.4{\sim}5.1^{\circ}C$ at the height of 40cm and $2.1{\sim}3.1^{\circ}C$ at the height of 80cm. Under the Night treatment, the air temperature was decreased about $3.4{\sim}3.8^{\circ}C$ at the height of 40cm and $2.2{\sim}2.7^{\circ}C$ at the height of 80cm. The daily average temperature in the substrate was in the order of the Control ($27.7^{\circ}C$) > Night ($24.1^{\circ}C$) > All-day ($22.8^{\circ}C$) treatment. Cooling the passage with either upstream blowing at $45^{\circ}$ or horizontal blowing at $180^{\circ}$ was effective in lowering the air temperature at a height of 50cm; however, no difference at a height of 100cm. Cooling the passage with perpendicular direction at $90^{\circ}$ was effective in lowering the air temperature at the height between 100 and 200cm above the floor; however, no effect on the temperature at the height of 50cm. A greater decrease in leaf temperature was found at 7 p.m. than that at 9. a.m. under both All-day and Night treatments. Fresh weight partitioning of fruit was in the order of the All-day (48.6%) > Night (45.6%) > Control (24.4%) treatment. A higher fruit production was observed under the All-day treatment, in which the accumulated average temperature was the lowest, and it may have been led to a higher proportion of photosynthate distributed to fruit than other treatments.

• Korean Journal of Agricultural Science
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• v.40 no.4
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• pp.325-331
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• 2013

This experiment has been carried out to determine optimal culture conditions for the production of cut flowers and tubers of Calla (Zantedeschia 'Golden Affair' and 'Black Magic') in highlands. Treatments consisted of various levels of root zone environments, Results are as follows: Calla 'Golden Affair' were grown with different mulching materials such as Non-mulching, Black film, reflective film, Rice hull. Mulching materials resulted in no difference in the number of cut flowers but flower length was highest in reflective film. Calla 'Black Magic' were treated with various soil water content, soil type and watering time. Number of cut flowers and flower quality were greatest when the plants were watered at -80 kPa soil water content. No symptoms of soft rot (Erwinia carotovora) was observed at this soil water content. The occurrence of soft rot was observed with similar percentage according to soil type and the soil water content. When Calla 'Black Magic' were watered at the time of soil surface drying, growth was greater compared to others. Air temperature and PPF affected plant growth and photosynthesis. Photosynthetic rate was greatest at $25^{\circ}C$ and PPF $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, while lowest at $28^{\circ}C$ and PPF $800{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Soft rot did not occur without regard to dipping treatment (0, 5, 10, 24, 48 hours) when the day and night temperature were maintained at $25^{\circ}C$ and $20^{\circ}C$, respectively.

• International Journal of Oral Biology
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• v.40 no.4
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• pp.167-173
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• 2015

The purpose of this study was to investigate the antibacterial effect of the low temperature atmospheric plasma device with needle tip designed for easy approach to the oral cavity and root canal against Streptococcus mutans, Enterococcus faecalis and Candida albicans. The antibacterial activities evaluated by measuring clear zone of agar plate smeared with each bacteria after plasma treatment. To quantify antibacterial effects, dilution plate method was used. In addition, scanning electron microscope (SEM) was used for observation of changes in bacterial morphology. As treatment time of plasma increased, the clear zone was enlarged. The death rate was more than 99%. The SEM results showed that the globular shape of bacteria was distorted. These results suggest that needle tip plasma could be an innovative device for prevention of dental caries, and treatment of apical infection and soft tissue diseases.

• Journal of the Semiconductor & Display Technology
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• v.19 no.1
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• pp.67-72
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• 2020

This study analyzes the method of adhesion and improvement between heat.er and RF filter in PE-CVD equipment through TRIZ method and proposes a solution. TRIZ Solution such as function analysis, 9-window matrix, ASIT, and Root cause analysis were used. The contact temperature between the heater and the RF filter was 20% and the surface temperature was lowered to 5.7℃, suggesting an improvement method for the thermal expansion of the PE-CVD equipment hot zone.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.6
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• pp.710-717
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• 1996

To obtain the basic informations on the farm cultivation of Eleutherococcus senticosus Max., field survey of the native habitat in Mt. Deokyu such as weather, soils, vegetation and growth was carried out. The habitat of E. senticosus is situated at 127$^{\circ}$ 45'E, 35$^{\circ}$ 52' N in Mt. Deokyu where the elev-tion ranges from 1,050 to 1,300 meters above the sea level. Mean annual temperature forecasted around the habitat was 5.8$^{\circ}C$, mean maximum temperature in August, 24.6$^{\circ}C$ ; mean minimum temperature in January, -13.5$^{\circ}C$ and relative humidity during the growth periods, over 95%. To divide the area according to climatic conditions was classified cool temperature and humid rain forest zone. In another view, it belonged to deciduous broad-leaf forest zone and soil texture was sandy loam with dark brown gravels. Acidity and P$_2$O$_{5}$ content of soil represented pH 5.2～5.6 and 10ppm, respectively. The growth of E. senticosus was poor under the low light intensity(relative 20% of full sun-light) at the growing place of the habitat and the propagation was conducted by root sucker. The natural vegetation was consisted of big trees, 3 species; shrubs, 8 species and herbs, 4 species.

• Journal of Welding and Joining
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• v.3 no.2
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• pp.42-51
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• 1985

The dynamic fracture toughness, fracture characteristics, impact tension and tensile properties of Al-Mg-Si T5 alloy and Al-Zn-Mg T6 alloy respectively welded with filler metal of Alcan 4043 were investigated. The dynamic fracture toughness values were obtained rapidly and simply for the specimen of small size by using instrumented Chirpy impact testing machine. the testing temperatures of the specimen were a range of room temperature and-196.deg. C. The results obtained in this experiment are summarized as follows. With decreasing the testing temperatures, dynamic tensile stress and fracture load were increased, on the other hand the deflection and impact value showed decreasing tendency in order of base metal>HAZ>weld. Changes of total absorbed energy were more influenced by the crack propagation energy than the crack initiation energy. At the low temperatures, the unstable rapid fracture representing the crack propagation appeared for the specimens of Charpy press side notched in Al-Zn-Mg alloy, but it was difficult to obtain the unstable rapid fracture in Al-Mg-Si alloy. Because of the development of plastic zone at the notch root, it was difficult to obtain thevalid $K_{1d}$ value in Al-Mg-Si alloy. Therefore the fatigue cracked specimens were effective in both Al-Mg-Si and Al-Zn-Mg alloys. With decreasing the impact testing temperatures, specimens underwent a transition from dimple-type transgranular fracture to lamella surface-type intergranular fracture because of the precipitate at the grain boundaries, impurities and crystal structure of the precipitates.s.

• Journal of agriculture & life science
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• v.44 no.4
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• pp.79-85
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• 2010

An analysis in heating effects of an electric radiator located in a 1-2W type chrysanthemum (3 cultivars) cultivation greenhouse installed in Gyeongsang National University drew the following conclusions. During the experiment period, the highest, average, and the lowest outside temperatures were in the ranges of $-3.8{\sim}21.3^{\circ}C$, $-5.2{\sim}16.1^{\circ}C$ and $-12.5{\sim}14.4^{\circ}C$, respectively, and the average relative humidity inside and outside the greenhouses were in the ranges of 43.5~98.6% and 35.2~100%, respectively. From mid-December to early February, the lowest outside temperature was recorded as approximately $-5.0{\sim}-10.0^{\circ}C$, which showed that it tended to be relatively lower than the temperatures recorded at the Jinju Meteorological Observatory. During the night, the leaf temperature measured directly under the radiator tended to be higher by $2{\sim}3^{\circ}C$ than that those at the middle point of the radiator, or higher by a negligible amount. In the case of root zone temperature, it was found that there was almost no difference between temperatures of the part directly under and the middle point, and the time when the highest temperature of root zone and other highest temperatures took place showed that there was about a 2-hour delay phenomenon. The total electricity consumption, energy supply and total heating cost during the experiment period were 2,800 kWh, 2,408,000 kcal and 112,000 won, respectively. When diesel, a kind of fossil fuel, was used as heating oil, the total heating cost was around 224,500 won. It was estimated that the total heating cost could be reduced by around 50% if a radiator was used.

• Journal of Plant Biology
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• v.14 no.4
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• pp.5-13
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• 1971

Pot and paddy field tests were conducted to study red discoloration of rice var. IR 667 leaves with reference to the leading Korean native variety Jinhung and Paldal, with the following results: 1. Minor elements such as Mn, Fe, B, Al, Ca and Si had no influence on the discoloration, but a supply of various soluble nitrogen compounds completely restricted it. The more prosperous the growth of IR 667 with nitrogen, the more severe the discoloration appears when nitrogen absorptin becomes limited. 2. Chlorotic pigments extracted from both IR 667 and Jinhung were compared spectrophotometrically, and found to have different spectral peaks. IR 667 had peak closer to red than Jinhung, indicating the characteristic of the variety. IR 667 was observed to be more sensitive to nitrogen deficiency than Jinhung or the other japonica variety. 3. It was concluded that all the factors limiting nitrogen supply for IR 667 growth, such as low nitrogen application, restriction of root respiration (low temperature, poor drainage, toxic gases or substances in the root zone, etc.) and pest injuries, would result in the appearance of the so-called red discoloration, because of the reduction in nitrogen uptake. Since, the discoloration of IR 667 is varietal characteristic when grown in Korea, control of it may be beneficial cultural practice in increasing grain yield, although the increased succeptibility to pests and a drop in the rate of maturity due to relatively high nitrogen level in the leaves may result in an unexpected drop in yield. It is anticipated that further exploration conducted from practical point of view will establish the relatioknships between the extent of red discoloration, nitrogen availability and grain yield in IR 667.