• Magazine of the Korean Society of Agricultural Engineers
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• v.27 no.2
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• pp.57-71
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• 1985

The characteristics of compaction and unconfined compressive strength were investigated by mixing with lime to all soils adjusted by given percentages of two kinds of clays to sand to obtain the most effective distribution of grain size and the optimum lime content for soil stabilization. In addition, unconfined compressive strength and durability tested by adding of sodium metasilicate, sodium sulfate, sodium carbonate, sodium gydroxide and magnesium oxide to lime-soil mixture mixed with 8 percent lime to adjusted soil having the mixing percentage of 60 percent of cohesive black clay and 40 percent of sand by weight to get the effect and the optimum content of chemicals. The results obtained were as follows; 1.With the addition of more lime, the optimum moisture content was increased, and the maximum dry density was decreased, whereas the more the amount of clay and the less was the maximum drt density. 2. In the soil having more fine grain size the unconfined compressive strength was larger in the earlier stage of curing period, in accordance with the longer period, the mixing percentages of sand to clay showing the maximum unconfined compressive strength, on the basis of 28-day strength, were 60% : 40% (black clay) and 40% : 60% (brown clay) respectively. 3. The reason why the soil adjusted with black clay was remarkably bigger in the unconfined compressive strength than ones adjusted with brown clay for all specimen of lime-soil mixture was the difference in the kind of clay, the amount of chemical compositions the value of pH. Black clay was mainly composed of halloysite that reacted with lime satisfactorily, whereas the main composition of brown clay was kaolinite that was less effect in the enhance of unconfined compressive strength. Also the difference of unconfined compressive strength was because black clay was larger in the amount of composition of calcium oxide and magnesium oxide in the value of pH affecting directly on the unconfined compressive strength of lime-soil mixture than brown clay. 4. In the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40%, on the standard of 7-day strength, the effect of chemical was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium hydroxide and sodium metasilicate. 5. The optimum amount of chemical being applicable to the maximum unconfined compressive strength of lime-chemical-soil mixture was 1 percent by weight for air dry soil in the case of adding sodium carbonated and 0.75 percent on sodium hydroxide, the unconfined compressive strength was increased continuously with increase of the amount of chemical up to 2 percent of chemical content is the lime-chemical-soil mixture added sodium metasilicate, sodium sulfate and magnesium oxide. 6. It was considered that the chemical played and accelerant role of early revelation of strength because the rate of increase of unconfined compressive strength of all of lime-chemical-soil mixtures was largest on the 7-day cured specimen. 7. The effect of test on freezing and thawing after adding suitable amount of chemical on the lime-soil mixture mixed with 8 percent of lime to soil that mixing percentage of sand to black clay was 60% : 40% was arranged in the order of magnesium oxide, sodium carbonate, sodium sulfate, sodium metasilicate and sodium hydroxide.

• Food Science of Animal Resources
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• v.29 no.3
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• pp.356-363
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• 2009

This study was carried out to investigate the effect of hot boning and curing condition on the quality characteristics of ground chicken breast. Treatments were cured by four conditions follows; control (general curing method), T1 (after hot-boning and then immediately cured), T2 (after hot-boning and immediately cured, then frozen), and T3 (after hot-boning, immediately frozen, refrigerated and then cured). The pH of chicken breast in the state of pre-rigor was 6.22. The pH of cold storage or freezing chicken breast meat respectively were 5.70 or 5.61. The pH of T1 and T2 treatments were significantly higher than those of control and T3 treatment (p<0.05). After stored for 1 wk, the pH value of T1 treatment had a higher value than those of other treatments. T1 treatment had the highest water holding capacity and the lowest cooking loss among all treatments, regardless of the cooking methods. The reduction in diameter for T1 and T2 treatments was lower than those of control and T3 treatment (p<0.05). T1 treatment had the lowest fat loss and moisture loss among all treatments, and the emulsifying capacity of T1 treatment was the highest. The protein solubility of T1 treatment was significantly lower than that of T3 treatment.

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.71-82
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• 2012

This research was carried out to estimate annual erosion and retreat rates by using datum-point and to identify the characteristics and causes of seasonal variations of sea-cliff slope in Pado-ri, Taean-gun. In the result, the erosion and retreat rates of sea-cliff were increased from spring to summer. The rates were increased rapidly between August and October, caused by the effects of extreme weather events such as severe rainstorms and typhoons, etc. Since then, the erosion and retreat rates of sea-cliff were decreased gradually, but the rates were increased again in winter due to the storm surge and mechanical weathering resulting from the repeated freezing and thawing actions of bed rocks. The factors that affect erosion and retreat rates of sea-cliff include the number of days with antecedent participation and daily maximum wave height. In particular, it turned out that the erosion is accelerated by strong wave energy during storm surges and typhoons. The annual erosion and retreat rates of study area for the past two years(from May 2010 to May 2012) were approximately 44~60cm/yr in condition of differences in geomorphological and geological characteristics at each point. These erosion and retreat rates were found to be higher than results of previous researches. This is caused by coastal erosion forces strengthened by extreme weather events. The erosion and retreat process of sea-cliff in the study area is composed by denudation of onshore areas in addition to marine erosion(wave energy).

• Journal of The Geomorphological Association of Korea
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• v.19 no.3
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• pp.23-36
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• 2012

This study aims to think about the problem of dolmens: the reasons for the presence of dolmens and how to construct it, at the point of view of geographical and geomorphological. The subjects of this study is the dolmens which locate between at Dogok Hyosanri and Chunyang Daesinri Hwasoon-gun, Jeonlanamdo. The study areas in Hyosanri, Daesinri has been observed as follows. First, the long axis direction of Dolmen upper stone and the slope one are the same. Second, tor, block stream, hockey stick, etc. Third, Composition of the soil silt> sand> clay is distributed in the order. Forth, The soil of high quality silt and the roundness of angular, sub-angular-level and the high frequency, peaks of quarts and illite clay minerals show. Fifth, in the result of $SiO_2/Al_2O_3$, $SiO_2/R_2O_3$, and CIA(Chemical Index of Alteration), Hyosanri, Daesinri areas show mechanical weathering was dominant and chemical weathering environment was not being progressed. The blocks used in construction of dolmens had moved to the bottom of slopes by mass movement such as solifluction then them which had been placed in the position seem to be used by people of Bronze. Based on the above results, the process of construction of dolmens can be estimated as follows. They would dig up the ground under the upper stone of dolmens, put the supporting stone in the place, then dig up earth, place into remains, close the obturating stones, then heal up earth.

• Korean Journal of Medicinal Crop Science
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• v.27 no.5
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• pp.322-329
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• 2019

Background: Studies have suggested that the northern provinces of Gangwon-do are good sites for licorice (Glycyrrhiza uralensis Fisch.) cultivation in Korea, as they have similar temperatures to its original locations in northern China. However, poor growth and freezing injury are often reported in Korea. Therefore, it is necessary to reassess the domestic cultivation site of licorice. Methods and Results: To determine the optimum temperature for cultivating licorice, the growth, yield, and pharmacological characteristics of G. uralensis were assessed in a temperature gradient tunnel at Eumseong, Chungcheongbuk-do, Korea in 2017. Plant height increased until the temperature rose to $5.9^{\circ}C$ above the local external temperature. Yield (㎏/10a) increased by 46.9% when the growing temperature was $1.5^{\circ}C$ to $3.0^{\circ}C$ (T2) above the external temperature and by 72.6% when the growing temperature was $3.0^{\circ}C-4.5^{\circ}C$ (T3) above the external temperature. However, a difference of $4.5^{\circ}C-5.9^{\circ}C$ (T4) above the external temperature, decreased the yield by 9.8% compared to that at T2. The glycyrrhizin content of G. uralensis roots in each temperature band was 0.72%, 0.53%, 0.91%, and 0.84% (T1, T2, T3, T4), these differences appear to result form individual plant variation rather than growth temperature. Conclusions: Based on the results of this study, we estimate that the temperature-based optimum cultivation site for G. uralensis in Korea is the south central region, rather than the northern province of Gangwon-do. Improvement in growth and yield maybe observed if the plantations in the central Jecheon (Chungcheongbuk-do, Korea) are expanded into the south central region.

• The Journal of the Convergence on Culture Technology
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• v.5 no.4
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• pp.395-399
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• 2019

The purpose of this study was to investigate shooting and fruiting characteristics of persimmon 'Hachiya' affected by sub-zero temperature at early budding stage. The number of developed shoots, and the number of shoots with young fruits, and the shooting and fruiting of terminal buds of one-year-old branch (1YOB) were significantly decreased with the sub-zero temperature treatment (SZT). The number of shoots developed in the top of 1YOB decreased 47.2% due to SZT. The number of shoots with fruits was significantly decreased at 50% or higher in non-budding rate of 1-YOB. Especially the number of fruits (Y) at the three terminal buds of 1YOB was significantly affected by SZT and the non-budding rate (X) as Y = -0.145X + 12.950 ($r^2=0.4672^*$). Therefore, in the early budding stage of persimmon, when tree is affected by SZT ($-2^{\circ}C$, 3 hours), shoots growth is reduced and increase of 10% in non-budding rate reduces 1.4 of fruits per the three terminal buds of 1YOB.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.5
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• pp.607-616
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• 2022

Corrosion and degradation of reinforced structures due to abnormal climates and natural disasters further accelerate the aging of structures. Coping with the decrease in structure performance, many old structures are being repaired and reinforced with low-weight and high-strength materials such as glass fiber composite material (GFRP). To further contribute, this paper focus on a more economical and eco-friendly material, basalt fiber composite (BFRP), which provide a more effective lateral constraint effect for seismic reinforcement. The main variables considered in this study are the curing temperature during the manufacturing of BFRP and the material characteristics of the target concrete member. The lateral constraint reinforcement effect was investigated through the evaluation of the performance of normal concrete and those with improved durability through fiber reinforcement. The reinforcement effect was 3.15 times for normal concrete and 3.72 times for fiber reinforced concrete, and the difference in reinforcement effect due to the improvement of the durability characteristics of the compression member was not significant. Lastly, the performance of the BFRP was compared with the results of the GFRP reinforcement from the previous study. The effect of the BFRP reinforcement was 1.18 times better than that of the GFRP reinforcement.

• Journal of The Korean Association For Science Education
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• v.43 no.2
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• pp.59-72
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• 2023

This study analyzed a group interview with six earth science teachers and eight middle school students to find out the evaluations and criteria they use to evaluate VR/AR contents (two virtual reality content and two augmented reality contents) in middle school science digital textbook. The study found the VR/AR contents were evaluated on four criteria as follows: VR/AR media characteristics; technical operation; user interface; and teaching-learning design. The evaluations can be summarized by each criterion. First, regarding VR/AR media characteristics, interesting features of VR/AR contents were considered relatively advantageous compared to other media like videos. However, its shortage of visual presence and inconvenience of using markers were mentioned as shortcomings. Second, in the technical operation criteria, teachers and students found the following conditions as technically challenging: failing to properly operate on a particular OS; huge volumes of contents in the application; and frequent freezing when using the application. Third, poor intuitiveness and lack of flexibility were found as negative aspects in user interface. Fourth, regarding teaching-learning design, the teachers evaluated whether the VR/AR contents delivered scientifically accurate information; whether they incorporated class goals set by teachers; and whether they can help students' inquiry. It turned out teachers gave negative feedbacks on VR/AR contents. The students evaluated VR/AR contents by assessing whether they help them with learning science but concluded they did not regard them necessary in science learning at school. Based on the findings, this study discusses which development direction VR/AR contents should take to be useful in teaching and learning science.

• Food Science and Preservation
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• v.17 no.1
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• pp.1-8
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• 2010

We investigated the effect of freezing on changes in the chemical components of semi-dried red pepper (SDRP). We used storage temperatures of $0^{\circ}C,\;-10^{\circ}C,\;-20^{\circ}C,\;and\;-70^{\circ}C$. After 30 days of storage, capsaicin content had decreased by 40% at $0^{\circ}C$ and by 21% at $-20^{\circ}C$. Initial vitamin C content was 1,358.02 mg%. Compared with control, the $0^{\circ}C$ storage group showed a significant decrease in vitamin C content but no such decrease was noted in the $-20^{\circ}C$ and $-70^{\circ}C$ storage groups after 30 days. ASTA values were not influenced by storage temperature or period, in agreement with previous results. We concluded that storage was effective at temperatures of less than $-20^{\circ}C$. Next, both dried red pepper (DRP) and SDRP were stored at $-20^{\circ}C$ for 12 months. DRP had the lower level of capsaicinoids (55.01 mg%) owing to the long drying time. After 12 months, SDRP capsaicinoid had decreased by 30-33%, compared with a decrease of 54% in DRP. Initial vitamin C contents were 721.48 and 955.25 mg% in DRP and SDRP, respectively, and, after 12 months, vitamin C loss in the SDRP group (37%) was less than that in fresh red pepper (FRP) samples (45%). Initial $\beta$-carotene content was greatest in the FRP group (259.82 mg%), and that of DRP decreased by 20% after 12 months. The color a/b value of SDRP (1.40) was greater than that of DRP (1.00).

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.171-178
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• 2013

The purpose of this study was to evaluate the sperm viability, normal acrosome and mitochondrial activity in the frozen-thawed fowl semen by different cryoprotectants. The experiment was carried out on 10 sexually adult roosters of Ogye. The semen was collected twice a week and pooled semen was diluted 1:1 EK extender containing no cryoprotectant at $5^{\circ}C$. After equilibration for 30 minutes, diluted chicken semen was diluted 1:1 extender containing either 7% dimethylacetamide (DMA), 7% dimethylformamide (DMF) or 7.5% methylacetamide (MA) at final concentration and was put in 0.5 mL plastic straws and frozen for 30 minutes by exposure to liquid nitrogen vapor 4 cm above the surface of liquid nitrogen, followed by plunging into liquid nitrogen. Frozen semen was thawed in water bath at $5^{\circ}C$ for 2 minutes. For cytometric analysis, the frozen-thawed semen was diluted with EK extender to a final concentration of 90 million spermatozoa per mL. Sperm membrane integrity was evaluated as SYBR-14 and propidium iodide (PI). Acrosome integrity was assessed with fluorescein isothiocyanate-labeled PSA and PI. The percentage of mitochondrial function was estimated by using Rhodamine123 (R123) and PI. In conclusion, freezing rooster semen by using 7% DMF as cryoprotectant was significantly highest in rates of survival and mitochondrial function while its rate of damage of acrosome was significantly lowest. As a result, DMF is the cryoprotectant that has the lowest influences on sperm membranes and acrosome integrity. Therefore it could be used for freezing method of animal genetic conservation method for poultry diversity.