• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.422-448
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• 1996

Low-temperature epitaxial growth of Si and SiGe layers of Si is one of the important processes for the fabrication of the high-speed Si-based heterostructure devices such as heterojunction bipolar transistors. Low-temperature growth ensures the abrupt compositional and doping concentration profiles for future novel devices. Especially in SiGe epitaxy, low-temperature growth is a prerequisite for two-dimensional growth mode for the growth of thin, uniform layers. UHV-ECRCVD is a new growth technique for Si and SiGe epilayers and it is possible to grow epilayers at even lower temperatures than conventional CVD's. SiH and GeH and dopant gases are dissociated by an ECR plasma in an ultrahigh vacuum growth chamber. In situ hydrogen plasma cleaning of the Si native oxide before the epitaxial growth is successfully developed in UHV-ECRCVD. Structural quality of the epilayers are examined by reflection high energy electron diffraction, transmission electron microscopy, Nomarski microscope and atomic force microscope. Device-quality Si and SiGe epilayers are successfully grown at temperatures lower than 600℃ after proper optimization of process parameters such as temperature, total pressure, partial pressures of input gases, plasma power, and substrate dc bias. Dopant incorporation and activation for B in Si and SiGe are studied by secondary ion mass spectrometry and spreading resistance profilometry. Silicon p-n homojunction diodes are fabricated from in situ doped Si layers. I-V characteristics of the diodes shows that the ideality factor is 1.2, implying that the low-temperature silicon epilayers grown by UHV-ECRCVD is truly of device-quality.

• FLOWER RESEARCH JOURNAL
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• v.17 no.4
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• pp.266-270
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• 2009

This experiment was conducted to investigate the effect of transfer date to a growth chamber and low temperature on growth and flowering of Jeffersonia dubia for free control of flowering period. According to transfer date, any plant did not sprout when plants were put in a growth chamber from Aug. 20 to Dec. 20. However, all the plants which were put in a growth chamber on Jan. 20 or Feb. 20 sprouted and resulted in flowering. The effect of beginning time and period of low temperature treatment were also observed. At the beginning time of Aug. 20, sprouting and flowering occurred as plant received more than 60 days of low temperature treatment. However, almost of al l the plants sprouted and flowered by only 30 days of low temperature treatment when the low temperature was given after Sep. 20. 60 days of low temperature given again after about three month growing period after dormancy breaking, resulted in resprouting of all plants and 70% of them flowered in this experiment.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.213-220
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• 2022

This study was conducted to investigate the effect of environmental factors such as water temperature and rearing density on the survival and growth of Litopenaeus vannamei under low salinity conditions. Overall, in the higher water temperature, the higher survival rate comes out and in the lower rearing density, the higher the survival rate does. In a study on feed efficiency, weight gain (WG) increased significantly as water temperature increased, and weight gain according to rearing density significantly decreased as rearing density increased. The growth rate of L. vannamei was faster when the water temperature was higher (water temperature 31℃) under low salinity conditions. In addition, in the evaluation of the growth rate according to the rearing density, it was confirmed that the growth rate was accelerated at a low rearinging density. It is believed that the results of this study will be usefully applied to the determination of the optimal rearinging density and breeding water temperature of L. vannamei in low salinity condition.

• Journal of Power System Engineering
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• v.4 no.1
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• pp.81-87
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• 2000

In this study, CT specimens were prepared from ASTM SA516 Gr. 70 which was used for pressure vessel plates for room and low temperature service. And we got the following characteristics from fatigue crack growth test carried out in the environment of room and low temperature at $25^{\circ}C,\;-60^{\circ}C,\;-80^{\circ}C\;and\;-100^{\circ}C$ and in the range of stress ratio of 0.05 by means of opening mode displacement. At the constant stress ratio, the threshold stress intensity factor range ${\Delta}K_{th}$ in the early stage of fatigue crack growth (Region I) and stress intensity factor range ${\Delta}K$ in the stable of fatigue crack growth (Region II) was increased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region. The straight line slope relation of logarithm $d{\alpha}/dN\;-{\Delta}K$ in Region II, that is, the fatigue crack growth exponent m increased with descending temperature at the constant stress ratio. It assumed that the fatigue crack growth rate $d{\alpha}/dN$ is rapid in proportion to descend temperature in Region II and the cryogenic-brittleness greatly affect a material with decreasing temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.2
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• pp.35-41
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• 1979

To observe the effects of temperature and photoperiod on the growth and yield of winter wheat (Triticum aestivum, L) eight varieties including Chang Kwang were tested at various treatments like longday-high temperature (24hrs-20\circ), shortdayhigh temperature (12hrs-20\circ), longday-low temperature (24hrs-14\circ) and shortday-low temperature (12hrs-14\circ). Among the traits measured, days to heading, plant height, spike length, number of spikes per hill and grain yield per hill were generally decreased at high temperature and long day treatment and increased at low temperature and shortday condition. Number of grains per spike was decreased at low temperature and short day condition while increased at longday and high temperature conditions. Grain weight was decreased significantly at high temperature and shortday while increased at low temperature and longday treatment.

• ALGAE
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• v.17 no.2
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• pp.117-125
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• 2002

Five microalgal species isolated from the Jeju coast and four microalgal stock strains in hatchery were cultured in order to investigate their adapation to extreme changes in environmental factors such as salinity, water temperatue, adn nutrients. In case of salinity variation, Nitzschia sp. of Bacillariophyceae, Isochrysis galbana of Haptophyceae and Tetraselmis gracilis of Prasinophyceae showed optimum growth at the low salinity of 20 and 25 psu. Amphora coffeaeformis and Chetoceros simplex of Bacillariophyceae, and Pavlova lutheri of Haptophyceae adapted well at the relatively high salinities of 30 and 35 psu. However Phaeodactylum tricornutum of Bacillariophyceae and Chlorella sp. of Chlorophyceae showed euryhaline property In case of water temperature variation, most of all the species studied wer inhibited at 10℃. C. simplex, Nitzschia sp., p. tricornutum, Chlorella sp. and T. gracilis grew well at above 20℃. A. coffeaeformis, I. galbana and P. lutheri adapted also at the high temperature of 30℃. Each microalgal strain showed different growth rates and its maximum biomass. Generally microalgal populations from the Jeju coast grow well in relatively high salinity and high water temperature. Their growth were inhibited at low water temperature, but not likely affected at low salinity. This study indicates that the microalgal populations could not be affected by abnormally low salinity phenomena, which have happened occasionally around the west Jeju coast in summer and have led macrobenthic animals to mass mortality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.631-635
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• 1995

In order to develop effective manufacturing method and to improve quality of low-salt fermented squid(10% of table salt), we investigated the effects of temperature, salinity and pH on the growth of Staphylococcus xylosus, Micrococcus varians, Pseudomonas diminuta and Pseudomonas D2 isolated from of low-salt fermented squid and the growth characteristics of these bacteria during fermentation were elucidated. All bacteria showed good growth during the process of low-salt fermented squid(pH 6~7 ; concentration of NaCl, 7~10% ; temperature, 7~1$0^{\circ}C$) and their cell numbers increased as fermentation proceeded under the same fermentation condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.5
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• pp.397-401
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• 2003

This experiment was conducted to know the characteristics of kernel growth as affected by various temperature regimes during grain filling using the varieties Hwaseongbyeo, Ilpumbyeo and Chucheongbyeo. The rice plants tested were grown in the natural condition at 1/5000a Wagner pots until flowering. After flowering, the rice plants were moved to controlled temperature conditions in a phytotron. The minimum/maximum daily temperature in the phytotron was controlled by 12/18, 15/21, 18/24, 21/27, and 24/$30^{\circ}C$, respectively. The grain weights were measured every three days after treatment. The mean daily kernel growth rate during active grain filling period showed different responses among varieties under various temperature regimes. The kernel growth rate of Chucheongbyeo was seriously reduced as temperature regimes were decreased. However, that of Ilpumbyeo was not influenced so critically. Ilpumbyeo showed some advantages in grain filling under low temperature regimes compared to Chucheongbyeo. The lag phase in grain filling of Chucheongbyeo was the longest among tested varieties, followed by Hwaseongbyeo under daily mean temperature regime of $15^{\circ}C$. Kernel weight of Ilpumbyeo increased fast in early grain filling phase under low temperature. This characteristic may be favorable for grain filling in temperate zone where the daily mean temperature is drastically dropped during grain filling period. Regression analysis with kernel growth rate and temperature showed the estimated critical low temperature for grain filling among varieties were $9^{\circ}C$, $12^{\circ}C$, $13^{\circ}C$ in Ilpumbyeo, Hwaseongbyeo and Chucheongbyeo, respectively. Under moderate temperature the duration of grain filling of Ilpumbyeo was longer than that of Chucheongbyeo. However, Under low temperature that of Ilpumbyeo was more favorable than Chucheongbyeo.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.264-268
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• 2001

In this study, CT specimens were prepared from spring steel(SUP9) processed shot peening which was room temperature, low temperature and high temperature experiment. And we got the following characteristics from fatigue crack growth test carried out in the environment of room, and high temperature at $25^{\circ}C,\; 50^{\circ}C, \;100^{\circ}C,\; 150^{\circ}C,\; and\; 180^{\circ}C$ in the range of stress ratio of 0.05 by means of opening mode displacement. The threshold stress intensity factor range $\DeltaK_{th}$ in the early stage of fatigue crack growth (Region I ) and stress intensity factor range $\Delta$K in the stable of fatigue crack growth (Region II) was decreased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature and high temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.4
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• pp.58-64
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• 2004

The purpose of this study is to predict the behavior of fatigue crack propagation as one of fracture mechanics on the compressive residual stress. We got the following characteristics from fatigue crack growth test carried out in the environment of room temperature and low temperature at $25^{\circ}C$, -6$0^{\circ}C$, -8$0^{\circ}C$, and -10$0^{\circ}C$ in the range of stress ratio of 0.3 by means of opening mode displacement. There is a difference between shot peened specimen and unpeened specimen. Fatigue crack growth rate of shot peened specimen was lower than that of unpeened specimen. Shot peening is improve the resistance of crack growth by fatigue that make a compressive residual stress on surface. That is the constrained force about plasticity deformation was strengthened by resultant stress, which resulted from plasticity deformation and compressive residual stress in the process of fatigue crack propagation. Temperature goes down, fatigue crack growth rate decreased.