• Journal of Life Science
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• v.18 no.8
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• pp.1066-1071
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• 2008

Schizandra fruit (Schizandra chinensis fructus) were dried by three processes, $50^{\circ}C$ (50HAD), $70^{\circ}C$ hot air (70HAD) and freeze drying process (FRD). Terpenoid were collected by SDE(Simultaneous Steam Distillation-Extraction) and followed by GC-MSD analysis. Also colour profile of each dried samples were measured by Hunter colorimeter. From fresh schizandra fruit, were detected 15 kinds of monoterpene, 28 kinds of sesquiterpene and 7 kinds of terpene alcohol. Myrcene(56.97 ${\mu}g/g$) and ${\gamma}$-terpinene(58.49 ${\mu}g/g$) were the major monoterpenes, ${\beta}$-elemene(120.16 ${\mu}g/g$), ${\alpha}$-bergamotene (103.45 ${\mu}g/g$), ${\gamma}$-selinene (75.97 ${\mu}g/g$), ${\beta}$-cubebene(66.69 ${\mu}g/g$), aristolene (51.25 ${\mu}g/g$) and ${\alpha}$-ylangene(28.06 ${\mu}g/g$) were the sesquiterpenes, and T-muurolol (96.45 ${\mu}g/g$) and terpinen-4-ol(46.02 ${\mu}g/g$) were the terpene alcohols. The dried samples lost more than half of terpenoid content of fresh schizandra fruit during early stage of drying process, and then the level of terpenoid content was not significantly changed. The content of sesquiterpenes appeared to increase until 6 day of FRD. The amount of residual terpene alcohols contained in schizandra fruit dried by FRD was more than those remained after drying by other processes, and schizandra fruit dried by 70HAD exhibited the least residual terpene alcohols. Brightness parameter $L^{\ast}$ decreased with the rise in the level of drying temperature, to which redness parameter $a^{\ast}$ and yellowness $b^{\ast}$ appeared to be similar.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.249-257
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• 2009

Surface runoff and erosion are responsible for extensive losses of top soil and agricultural productivity. In this study, a laboratory experiment was conducted to investigate the effects of different polyacrylamides (PAM) on the protection of soil from erosion and turbidity in loamy sand soil. To accomplish this, 10 and 40 kg $ha^{-1}$ of PAM were applied to the soil surface. The effects of rainfall on 10 and 20% slopes were then evaluated in the laboratory using a rainfall simulator. After air drying, the surface was subjected to rain at 30 mm $hr^{-1}$. The silt+clay of the runoff from samples treated with 10 kg PAM $ha^{-1}$ reduced by 43% and 13% when the 10% and 20% slopes were evaluated, respectively, when compared with the tap water without PAM treatment as control. The mean contents of silt+clay were reduced as the amount of PAMs applied increased at both slopes. Specifically, samples treated with 40 kg PAM $ha^{-1}$ showed reductions in the silt+clay of the runoff to 88% and 85% when the 10% and 20% slopes were evaluated, respectively, when compared to control. Furthermore, the mean turbidity of runoff in the 40 kg PAM $ha^{-1}$ treatment was reduced to 94.7% and 84.8% when the samples were subjected to 10% and 20% slopes, respectively, when compared to the control. Taken together, these findings indicate that PAM treatment will improve water pollution and agricultural productivity on sloped land via a reduction in soil erosion.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.55-61
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• 2009

Recently, the number of high-rise buildings being built in Korea by major construction companies for residential and commercial use has been increasing. When constructing a high-rise building, it is necessary to apply massive amounts of concrete to form a mat foundation that can withstand the huge load of the upper structure. However, it is of increasing concern that due to limitations in terms of the amount of placing equipment, available job-sites and systems for mass concrete placement in the construction field, it is not always possible to place a great quantity of concrete simultaneously in a large-scale mat foundation, and for this reason consistency between placement lift cannot be secured. In addition, a mat foundation Is likely to crack due to the stress caused by differences inhydration heat generation time. To derive a solution for these problems, this study provides test results of a hydration heat crack reduction method by applying placement lift change and setting time control with a super retarding agent for mass concrete in a large-scale mat foundation. Mock-up specimens with different mixtures and placement liftswere prepared at the job-site of a newly-constructed high-rise building. The test results show that slump flow of concrete before and after adding the super retarding agent somewhat Increases as the target retarding time gets longer, while the air content shows no great difference. The setting time was observed to be retarded as the target retarding time gets longer. As the target retarding time gets longer, compressive strength appears to be decreased at an early stage, but as time goes by, compressive strength gets higher, and the compressive strength at 28 days becomes equal or higher to that of plain concrete without a super retarding agent. For the effect of placement lift change and super retarding agent on the reduction of hydration heat, the application of 2 and 4 placement lifts and a super retarding agent makes it possible to secure consistency and reduce temperature difference between placement lifts, while also extending the time to reach peak temperature. This implies that the possibility of thermal crack induced by hydration heat is reduced. The best results are shown in the case of applying 4 placement lifts.

• Elastomers and Composites
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• v.46 no.4
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• pp.277-283
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• 2011

In this study, engineering grade and high intensity reflective sheets were prepared with glass beads and their reflection performance and physical properties were investigated. The reflective sheets prepared by using glass beads are divided into enclosed or encapsulated lens type, depending on whether the glass beads are open in air or not. Because of an extra layer on the glass bead surface, the enclosed lens type reflective sheets show very little change in the properties by bad weather conditions, compared to encapsulated lens type reflective sheets. Optimization of the amount of glass beads on the surface was carried out, which determines the retroreflective properties. Enclosed and encapsulated lens type reflective sheets with various colors were prepared and their coefficients of retroreflection were determined. The encapsulated type reflective sheet with white color shows a coefficient of retroreflection of $210.4cd/1x{\cdot}m^2$, which is higher than the enclosed type ($74cd/1x{\cdot}m^2$). Effect of washing on the reflective property and adhesive power of the reflective sheets was investigated, and it is found that the number of glass beads decreased with washing and the aluminum layer deposited was damaged extensively in the encapsulated lens type reflective sheets.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.382-389
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• 2020

Soil properties in opencast mines are a key factor in reclamation (revegetation) of mining areas. In this study we determined the soil physical and chemical properties of kaolinite tailings, reclaimed areas, and adjacent natural red pine (Pinus densiflora S. et Z.) forests in kaolinite opencast mines in Sancheong-gun, Gyeongsangnam-do. Six sites were chosen for collection of soil samples to determine soil physical and chemical properties at a soil depth of 10 cm. Soil bulk density was significantly higher (P < 0.05) in the kaolinite tailings (1.51 g·cm-3) than in the reclaimed areas (1.19 g·cm-3) and red pine forests (0.93 g·cm-3), whereas air phase in the kaolinite tailings (14.2%) was significantly lower than in the red pine forests (32.6%). Clay content in the red pine forests was significantly higher than in the reclaimed areas (18.7%) or kaolinite tailings (14.8%), whereas soil structural stability index was significantly lower in the reclaimed areas (1.61%) and kaolinite tailings (0.87%) than in the red pine forests (7.75%). Soil pH was significantly higher in the kaolinite tailings (pH 6.68) and reclaimed areas (pH 6.27) than in the red pine forests (pH 5.31). Soil organic carbon and total nitrogen were significantly higher in the red pine forests (C: 36.03 mg·g-1; N: 2.08 mg·g-1) than in the reclaimed areas (C: 5.00 mg·g-1; N: 0.31 mg·g-1) than in the kaolinite tailings (C: 2.12 mg·g-1; N: 0.07 mg g-1). The amount of available phosphorus was not significantly different among the three treatments. The concentration of exchangeable potassium was significantly lower in the kaolinite tailings (0.08 cmolc·kg-1) than in the reclaimed areas (0.21 cmolc·kg-1) and red pine forests (0.30 cmolc·kg-1). These results indicate that, because of high soil bulk density and low soil organic carbon, total nitrogen, available phosphorus, and exchangeable potassium in kaolinite tailings and reclaimed mining areas, soil nutrient management is needed in order to reclaim the vegetation in these type of areas.

• The korean journal of orthodontics
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• v.27 no.3 s.62
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• pp.503-513
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• 1997

This study was undertaken to investigate the effect of oxygen tension on the activity and function of the cells derived from human periodontal ligament by measuring cell activity, total protein synthesis, collagen synthesis, $IL-1{\beta},\;IL-6,\;TNF-{\alpha}$ Human periodontal ligament fibroblasts were collected from premolars extracted for orthodontic treatment and incubated in the environment of $37^{\circ}C,\;5\%\;CO_2,\100\%$ humidity. After the fifth to sixth passage they were used for the experiment. Gaspack system to which $0.2{\mu}m$ Millipore filter was attached was connected to mixed-gas tanks. The mixed gases were composed of $10\%\;O_2,\;5\%\;CO_2,\;85\%\;N_2$ in hyoxic group or $90\%\;O_2,\;5\%\;CO_2,\;5\%\;N_2$ in hyperoxic group and $5\%\;CO_2,\;95\%$ air for control. After incubation in $37^{\circ}C$ for 2, 4, 6 days, cell activity was determined by tetrazolium(MTT) assay and total protein synthesis was assayed using sulforhodamine B(SRB). And measurement of 4-hydroxyproline was performed to assess collagen synthesis md $IL-1{\beta},\;IL-6,\;and\;TNF-{\alpha}$ were measured by enzymeimmunoassay. The results were as follows. 1. The cell activity and total protein synthesis in hypoxic group were a little higher than or almost the same with those in control group. 2. In hyperoxic group, the cell activity was lower than that in control group and total protein synthesis was decreased. 3. Collagen synthesis was significantly decreased initially in both hypoxic and hyperoxic group and increased nearly to the level of control group as the duration of cell incubation was longer 4. As a result of enzymeimmunoassay, the amount of cytokines was $IL-6,\;TNF-{\alpha}\;and\;IL-1{\beta}$ in order. 5. $IL-6,\;TNF-{\alpha}\;and\;IL-1{\beta}$ were increased more rapidly in both hypoxic and hyperoxic group than in control group as the duration of cell incubation was longer. 6. There were more $IL-6\;and\;TNF-{\alpha}$ in hyperoxic group than in control group after 6 days, and there were more $IL-6\;and\;TNF-{\alpha}$ after 6 days than after 2 or 4 days in hyperoxic group. These results suggested that oxygen tension might modulate the production of extracellular matrix and cytokines in the cells derived from human periodontal ligament.

• Journal of Animal Environmental Science
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• v.10 no.3
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• pp.141-154
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• 2004

The solar powered water pump is very ideal equipment because solar power is more intensive when the water is more needed in summer and it is very helpful in the rural area, in which the electrical power is not available. The average so]ar radiation energy is 3.488 kWh/($m^2{\cdot}day$) in Korea. In this study, the automatic control logic and system of the water pump driven by the radiation energy were studied, designed, assembled, tested and analyzed for realizing the solar powered water pump. The experimental system was operated automatically and the cycle was continued. The average quantity of the water pumped per cycle was about 5,320 cc. The cycle time was about 4.9 minutes. The thermal efficiency of the system was about $0.030\%$. The pressure level of the n-pentane vapour in flash tank was 150$\%$450 hPa(gauge) which was set by the computer program for the control of the vapour supply. The pressure in the condenser and air tank during cycles was maintained as about 600 hPa and 1,200 hPa respectively. The water could be pumped by the amount of 128kg/($m^2{\cdot}day$) with the efficiency of $0.1\%$ and the pumping head of 10 m for the average solar energy in Korea.

• Journal of the Korean Wood Science and Technology
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• v.45 no.5
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• pp.580-587
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• 2017

Woodfiber insulation board can be considered as a one of the key material for low energy consumption, comfortable and safety construction of residential space because of its eco-friendly and high thermal insulation performance. This study was carried out to investigate the formaldehyde (HCHO) total volatile organic compounds (TVOC) emission properties and combustion shapes by flame test of low density fiberboards (LDFs) prepared with different adhesives. HCHO TVOC emission and combustion properties of LDFs prepared by melamine urea formaldehyde (MUF), phenol formaldehyde (PF), emulsified methylene diphenyl diisocyanate (eMDI) and latex resin adhesives were measured by desiccator method, 20 L chamber method, and flame test, respectively. As results, LDFs manufactured by MUF, eMDI and latex resin adhesives satisfied the Super $E_0$ grade of HCHO emission performance except PF resin. Furthermore, TVOC emission of all LDFs were satisfied the Korean indoor air quality standard (below $400{\mu}g/m^2{\cdot}h$). Especially, LDF with eMDI resin adhesive showed the lowest HCHO and TVOC emissivity, that $0.14mg/{\ell}$, $12{\mu}g/m^2{\cdot}h$, respectively. However, eMDI emitted the small amount ($3{\mu}g/m^2{\cdot}h$) of toluene in VOC components. In the flame test, LDF with MUF resin adhesives showed the most favorable shape after flame test compare to LDFs prepared other adhesives. Based on HCHO and TVOC emission, and combustion shapes, MUF resin adhesive may be recommended to prepare LDF for insulation purpose.

• Research in Plant Disease
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• v.8 no.2
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• pp.84-91
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• 2002

Disease forecasting in Korea was first studied in the Department of Fundamental Research, in the Central Agricultural Technology Institute in Suwon in 1947, where the dispersal of air-borne conidia of blast and brown spot pathogens in rice was examined. Disease forecasting system in Korea is operated based on information obtained from 200 main forecasting plots scattered around country (rice 150, economic crops 50) and 1,403 supplementary observational plots (rice 1,050, others 353) maintained by Korean government. Total number of target crops and diseases in both forecasting plots amount to 30 crops and 104 diseases. Disease development in the forecasting plots is examined by two extension agents specialized in disease forecasting, working in the national Agricul-tural Technology Service Center(ATSC) founded in each city and prefecture. The data obtained by the extension agents are transferred to a central organization, Rural Development Administration (RDA) through an internet-web system for analysis in a nation-wide forecasting program, and forwarded far the Central Forecasting Council consisted of 12 members from administration, university, research institution, meteorology station, and mass media to discuss present situation of disease development and subsequent progress. The council issues a forecasting information message, as a result of analysis, that is announced in public via mass media to 245 agencies including ATSC, who informs to local administration, the related agencies and farmers for implementation of disease control activity. However, in future successful performance of plant disease forecasting system is thought to be securing of excellent extension agents specialized in disease forecasting, elevation of their forecasting ability through continuous trainings, and furnishing of prominent forecasting equipments. Researches in plant disease forecasting in Korea have been concentrated on rice blast, where much information is available, but are substan-tially limited in other diseases. Most of the forecasting researches failed to achieve the continuity of researches on specialized topic, ignoring steady improvement towards practical use. Since disease forecasting loses its value without practicality, more efforts are needed to improve the practicality of the forecasting method in both spatial and temporal aspects. Since significance of disease forecasting is directly related to economic profit, further fore-casting researches should be planned and propelled in relation to fungicide spray scheduling or decision-making of control activities.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.5
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• pp.42-52
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• 2009

Recreational forests are catching on as places for personal development through recreation, association with people, education about nature, mind relaxation and spiritual peace. However, the value and significance of recreational forests with various functions are easily overlooked. Whoever pays fees for admission to facilities are able to enjoy fresh air, a comfortable environment, and space for rest. It should be taken into consideration whether the fee which customers pay is appropriate for the value of nature they are enjoying. This study is involved in giving the right recognition to the value of recreation and environment by estimating economically the value of the environment in which visitors stay, and presenting the appropriate price. The most efficient way to achieve this goal is through an economic approach, which suggests following established research skills and yielding suitable and accurate amounts of money. The environmental value of a recreational forests is estimated through contingent valuation method(CVM), which is chosen among several methods to estimate public facilities because the value of recreational forests has strong characteristics as public facilities which are not traded in the market. The annual recreation value per person of surveyed recreational forests is Willingness To Pay(WTP) with a mean between about 16,000 won and 25,400 won. The recreation value of one recreational forest surveyed is annually between approximately 1.7 billions won and 2.7 billions won. The annual recreation value of 85 national and public recreational forests is presumed to be between about 140 billions won and 230 billions won. The presumed amount of money is the environment in which visitors can enjoy whenever they invest some money and time. Indeed, it is more than that; it provides visitors with a greater sense of satisfaction and the recognition of the preciousness of nature and the environment.