• Journal of Navigation and Port Research
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• v.30 no.1 s.107
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• pp.113-117
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• 2006

The object qf this experiment was the evaluation of the growth rate of frost layer conditioned by inlet air's velocity, temperature and relative humidity on the copper tube in evaporator. In this experiment, the inlet air's velocity were $0.3^m/_s,\;0.6^m/_s,\;0.9^m/_s,$ temperature were $15^{\circ}C,\;20^{\circ}C,\;25^{\circ}C$ and the variation of relative humidity was $70\%~90\%$. And the brine temperature flowing through the copper tubes was kept $-15{\circ}C$ because generally cooling temperature range is constantly $-15^{\circ}C$ in the heat exchanger for air conditioning system It was found that the amount of frost generation increased so that the relative humidity, velocity and temperature of supply air increased.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.395-398
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• 2005

In recent years, the applications of high-strength concrete have increased, and high-strength concrete has now been used in many parts of the world. The growth has been possible as a. result of recent developments in material technology and a demand for higher-strength concrete in Korea. In this study, we have an object to produce the ultra-high strength concrete(Super-Con) of over 100MPa with low price materials. First, the binders for Super-Con should be selected by the tests; setting time of paste, flow value and strength of mortar. From the test results, the binders are blended with ordinary portland cement, pulverized portland cement and silica fume. Fundamentally the compressive strength, frost resistance and chloride resistance are investigated.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.3
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• pp.162-169
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• 2016

The agrometeorological reference index means 'the agrometeorological damage possibility' or the possibility of the normal year climate condition to damage the crop cultivation in a certain region. It is a reference used to compare the cultivation risk of a crop by region. The global climate warming is expected to increase the winter temperature. At the same time, the frequency of extreme weather events will also increase. Therefore, people pay attention to the potential of low temperature-induced damages (e.g., frost damage and injury) to fruit trees under the future climate condition. However, simple damage projection based on climate conditions does not help the climate change adaptation in the practical aspect because the climate change affects the phenology of fruit trees as well. This study predicted the phenology of the pear, peach, and apple trees by using the climate change scenarios of major regions. Furthermore, low temperature induced agrometeorological reference indices were calculated based on the effects of temperature on each plant growth stage to predict the damage possibility. It was predicted that the breaking rest would delay more in the future while the bud-burst date and flowering date will be earlier. In Daegu, Jeonju, and Mokpo, the breaking rest delayed more as time passed. The bud-burst date and flowering date of Seoul and Incheon regions were later than other regions. Seoul and Incheon showed a similar pattern, while Daegu and Jeonju revealed a similar pattern. Busan and Mokpo also showed a similar pattern. All regions were safe from the frost damage during the dormancy period. However, plants were vulnerable to frost damage between the breaking rest and the bud-burst period. Regions showed different frost damage patterns between the bud-burst period and the flowering period. During the bud-burst and flowering period, the risk level decreased in general, although the risk of some areas tended to increase.

• Journal of the Korean earth science society
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• v.40 no.6
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• pp.606-612
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• 2019

In this study, to estimate the occurrence of frost that has a negative effect on th growth of crops, we constructed to the statistical model. We factored such various meteorological elements as the minimum temperature, temperature at 18:00, temperature at 21:00, temperature at 24:00, average wind speed, wind speed at 18:00, wind speed at 21:00, amount of cloud, amount of precipitation within 5 days, amount of precipitation within 3 days, relative humidity, dew point temperature, minimum grass temperature and ground temperature. Among the diverse variables, the several weather factors were selected for frost occurrence estimation model using statistical methods: T-test, Variable importance plot of Random Forest, Multicollinearity test, Akaike Informaiton Criteria, and Wilk's Lambda values. As a result, the selected meteorological factors were the amount of cloud, temperature at 24:00, dew point temperature, wind speed at 21:00. The accuracy of the frost occurrence estimation model using Random Forest was 70.6%. When it applied to the main production areas of vegetables, a estimation accuracy of the model was 65.2 and 78.6%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.20
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• pp.115-121
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• 1975

To achieve self-sufficiency in good production, cotton should be grown after barley in the southern part of Korea. But, this cropping system reduces cotton yields and fiber qualities in the current leading cotton varieties because of the short frost-free growth period. Ethrel-treated plots shortened the time to open boll by about 20days, increased the percentage of open bolls before the first frost from 38% to 93% and increased yield by 15-38%. There are not significant differences in staple length, tensile strength of the fiber, single bollweight, 100 seeds weight and germination percentage of the seeds between Ethrel-treated and untreated plots. Ethrel should be recommended to the farmers growing cotton after barley harvest.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.337-344
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• 2019

The purpose of this study is to explore the uncertainty as the healing function in the poetry of Robert Frost. One of the therapeutic functions in poetry therapy is to make us look into life from a new perspective, which appears in the uncertainty of his poetry. His uncertainty is based on his peculiar poetic theory and philosophy of dualism. This paper reviews these things and deals with aspects of the uncertainty in detail through his poems. The result of this study shows that Frost conveys elements of ambiguity, illogical development and unpredictability in our society and fear, loneliness and anxiety in our daily life, and also offers realistic depictions of complex life as a therapeutic medium for overcoming these problems. So it seems that his poetry provides us with a recovery of psychic health and a possibility of healing and personal growth. Furthermore we need a practical in-depth study on the healing function of English poetry.

• The Korean Journal of Ecology
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• v.24 no.5
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• pp.281-288
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• 2001

The relationships between the growths of Abies koreana W. and climatic factors were analyzed by the use of tree-ring analysis at the subalpine belt of Mt. Halla National Park. The four cores were extracted from each 21 trees at north-facing slope (1,900m a.s.1.). The site chronology was established on the periods from 1912 to 1999. The growth of A. koreana was very poor, in particular in the years of 1982, 1988 and 1996. Simple correlation was employed to analyze the relationship between the growth of A. koreana and climatic factors. The result of simple correlation indicates that the growth of A. koreana represent positive correlations both with the mean temperatures of April and previous November, and the precipitation of previous December and January. The presence of large number of frost-damaged scars in the individual trees of A. koreana implies that local freezing temperature conditions at Mt. Halla have occurred in 1964, 1965 and 1966. The correlations between the fir chronology SOI(Southern Oscillation Index) of previous January, February and November were significantly positive. The growth ratio of A. koreana demonstrates that this species is sensitive to seasonal variations. As the winter temperature rises, the growth ratio of A. koreana decreases, on the other hand, the increase of autumn temperature accelerates the growth ratio of A. koreana. The growth decline of A. koreana was observed from 51 cores out of the 54 cores, and the overall growth declines have initiated at 1978, 1982 and 1988. Distinct growth decline of A. koreana in the range of 70% is noticed at 34 cores out of the 51 cores. The decline of, A. koreana growth appears to be related to the winter temperature which has increased since mid-1970s.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.415-419
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• 2014

A Cymbidium variety 'Snow Bell' (C. kanran ${\times}$ C. Jack Frost) was developed at the National Institute of Horticultural & Herbal Science, Rural Development Administration in 2011. A cross between C. kanran with small-sized greenish colored flowers and C. Jack Frost with bright pink colored flowers, was conducted in 1999. Based on flower color, leaf shape, flower stalk, and vigor one line was selected. Evaluation and selection trials were conducted from 2006 to 2010. 'Snow Bell' has a light pink sepal (RHS, R56D), red lip (R56A) and a leaf length of 47.5 cm. The average number of flowers on each peduncle is 13.8 and the flower diameter is 6.2 cm. The characteristics of petals and sepals show some incurve and some spreading. 'Snow Bell' has a vigorous growth and a round flower. It has an adequate peduncle height of 50.7 cm compared with leaf length of 47.5 cm, and start blooming in December. In electronic nose analysis, the degree of fragrance between 'Snow Bell' and the C. kanran was similar and both of them showed strong scents, although they had different fragrance patterns.

• Journal of Ecology and Environment
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• v.38 no.1
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• pp.1-14
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• 2015

Whilst it is clear that increasing temperatures from global environmental change will impact the positions of alpine treelines, it is likely that a range of regional and local scaled factors will mediate the overall impact of global scale climate drivers. We summarized 12 categories of abiotic and biotic factors as 4 groups determining treeline positions. First, there are global factors related to climate-induced growth limitation and carbon limitation. Second, there are seven regional and local factors related to treeline dynamics including frost stress, topography, water stress, snow, wind, fire and non-fire disturbance. Third, species-specific factors can control treeline dynamics through their influence on reproduction and life history traits. Fourth, there are positive feedbacks in structuring the dynamics of treelines. Globally, the commonly accepted growth limitation hypothesis is that growth at a treeline is limited by temperature. Meanwhile, positive feedbacks between canopy cover and tree establishment are likely to control the spatial pattern and temporal dynamics of many treelines. The presence of non-linear dynamics at treelines has implications for the use of treelines as barometers of climate change because the lagged responses and abrupt shifts inherent in non-equilibrium systems may combine to mask the overall climate trend.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.21 no.1
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• pp.133-143
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• 2018

In spite of the growing importance of landscaping trees, the rate of flawed and withered trees damaged by pest, disease, drought or frost is increasing. In order to evaluate the performance of the Tree Protective Pad, which are developed to reduce the failure ratio in landscape planting, the tree protective pad for 'digging', 'pest controlling', and 'insulating' are tested based on the five functional criteria; moisturizing effect, wither preventive effect, pest and disease control, thermal effect, tensile strength, and environmental performance. The result of this study is as follows. The moisturizing effect of the tree protective pad for digging is found to be outstanding. According to the result of testing the pad on trees, in particular, it is better than jute tape in wither preventive effect, which means it is expected to prevent flaw and wilt from planting during the improper seasons like summertime. The experiment of installing the protective tree pad for pest controlling to the trunk of Quercus mongolica shows that preventive effect of the pad from diseases and insects is superior, and it also has economical effect by reducing the use of agricultural chemicals. The comparative test of the pad for insulating and jute tape proves that the temperature of the pad is about $2^{\circ}C$ higher than outside. The rate of tensile strength and biodegradation of the pad exceeds the optimal level, so it is revealed that the pad may be the work efficient and environment-friendly product. Likewise, by timely irrigating trees, the tree protective pad economically prevents trees from pest, disease,drought or frost, which may be caused by improper seasonal or delayed planting. As a means of reducing the flaw and facilitating the growth of trees, the exceptional performance of the pad is expected to effectively used in landscape planting and management.