• Korean Journal of Agricultural Science
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• v.12 no.2
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• pp.292-308
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• 1985

This study was performed to obtain the basic data which can be applied to the use of foamed mortars using foaming agent of prefoamed type. The data was based on the properties of foamed mortars depending upon various mixing ratios of cement to fine aggregates, flow values and foam-cement ratio to compare those of cement mortar. The results obtained were summarized as follow; 1. At the mixing ratio of 1:0 and the foam-cement ratio of 6.00%, the increasing rate of water-cement ratio was 25% by flow $200{\pm}5mm$, 28% by flow $240{\pm}5mm$ and 32% by flow $280{\pm}5mm$. But it decreased as the mixing ratio gets poorer. The result showed that water amount increased because of the high viscosity caused by the increase of foam-cement ratio. The decrease of water-cement ratio was the greatest when the foam-cement ratio was 1.50%. 2. Absolute aridity bulk density of foamed mortars decreased with the increase of foam-cement ratio and the decrease of flow values. 3. Generally, compressive, tensile and bending strenghs of foamed mortars decreased with the decrease of flow values and the increase of foam-cement ratio. 4. The compressive strength was in proportion to tensile strength. It was estimated that the compressive strength was 8.8 times of tensile strength. The compressive strength was in proportion to bending strength. It was estimated that the compressive strength was 4.0 times of bending strength. The bending strength was in proportion to tensile strength. It was estimated that the bending strength was 2.1 times of tensile strength. 5. At the mixing ratio of 1:1 the lowest absorption rates were showed by foamed mortars, respectively. It was significantly higher at the early stage of immersed water.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.9
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• pp.917-925
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• 2006

The aim of our research was to apply experimental design methodology in the optimization of photocatalytic degradation of azo dye(Reactive orange 16). The reactions were mathematically described as a function of parameters amount of $TiO_2(x_1)$, and dye concentration($x_2$) being modeled by the use of the Box-Behnken method. The results show that the responses of color removal(%)($Y_1$) in photocatalysis of dyes were significantly affected by the synergistic effect of linear term of $TiO_2(x_1)$ and dye concentration($x_2$). Significant factors and synergistic effects for the $COD_{Cr}$, removal(%)($Y_2$) were the linear term of $TiO_2(x_1)$ and dye concentration($x_2$). However, the quadratic term of $TiO_2(x_1^2)$ and dye concentration($x_2^2$) had an antagonistic effect on $Y_1$ and $Y_2$ responses. Canonical analysis indicates that the stationary point was a saddle point for $Y_1$ and $Y_2$, respectively. The estimated ridge of maximum responses and optimal conditions for $Y_1:(X_1,\;X_2)$=(1.11 g/L, 51.2 mg/L) and $Y_2:(X_1,\;X_2)$=(1.42 g/L, 72.83 mg/L) using canonical analysis was 93% and 73%, respectively.

• The Journal of the Korean bone and joint tumor society
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• v.14 no.1
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• pp.25-32
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• 2008

Purpose: This study was performed to evaluate the efficiency of Hydroxyapatite ($Bongros^{(R)}$-HA) what use for bone defect after operative treatment of benign bone tumor. Materials and Methods: Hydroxyapatite, was used to treat bone defect after operative treatment of benign bone tumor from September, 2006 to December, 2007. A total of 17 benign bone tumor cases (10 males and 7 females) with mean age of 28.5 was observed studied. The diagnoses were fibrous dysplasia in 8 cases, solitary bone cyst in 5 cases, and giant cell tumor in 4 cases. In categorization by location of tumor, there were 6 cases of proximal femur, 3 cases of proximal femur, 3 cases of proximal tibia, 4 cases of proximal humerus, and 1 case of hip bone. Autogenous bone was used with Hydroxyapatite in 4 cases, and only Hydroxyapatite used in 13 cases. Periods of Follow-up were from 3 months to 15 months, and mean period were 7.5 months. Amount of graft resorption and bone formation was observed with compare of post operation radiograph and the difference was shown by percentage. Results: More than 98% bone uptake was observed after mean 4.5 months, and more than 98% bone formation was observed after mean 6.2 months. Lesser bone defect size showed faster bone formation and it was statistically significant result (P=0.012). But other comparative studies on other factors such as sex, age of patients and combination of autogenous bone were no statistically significant differences in graft resorption and bone formation. And there was no significant complications in periods of follow-up. Conclusion: Hydroxyapatite is considered as one of useful method of bone defect after operative treatment of benign bone tumor.

• Journal of the Korean earth science society
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• v.39 no.3
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• pp.250-259
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• 2018

We investigated the petrological features of the stone materials used in the Jeolla Usuyeong rampart and estimated their provenance through the geological survey. The Jeolla Usuyeong was designated as a historic site (No. 535) on 2016. Since the remaining rampart is less than 15%, it is necessary to make conservation on it. In this study, we discriminated the stone materials used for the rampart according to their petrographic characteristics and estimated the volume proportion of each stone by the rock type. Also, we measured the whole-rock magnetic susceptibility. The petrographic features of the stones in the rampart were compared with those in the vicinity by their mineral composition and texture. The stone materials of the rampart mainly consist of the tuff, lapilli tuff, and lapilli stone. Among these three kinds of rocks, lapilli tuff is quantitatively the most abundant (60.3%), the next is tuff (34.7%), and lapilli stone (2.5%) shows the least amount. The whole-rock magnetic susceptibility of the tuffaceous rocks can be divided by the value of $1.0{\times}10^{-3}$ SI unit. Also, the compressive strength of tuff exhibits about 156 MPa, which is adequate to reuse for the repairing work. Petrological comparisons between stone materials and outcrop rocks distributed around the Hwawon peninsula leads to a conclusion that the stone materials of the rampart are likely to have been delivered from the Dongoeri and Sindeok-ri. Judging from the results of the comparison on the frequency of use and physical properties among the tuffaceous rocks, tuff is considered to suitable for restoring the rampart.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.343-348
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• 2008

To investigate the effects of incorporation of green manures (GM) into a sandy loam soil on growth, yield, and nutrient uptake of tomato (Lycoperiscon esculentum Mill.) and nutrient balances (input minus offtake of nutrients), five tomato production systems were compared under the condition of plastic film house: 1) a no input system (no additional amendment or inputs, 0-To-0-To); 2) a conventional system (application of N-P-K chemical fertilizers, Cf-To-Cf-To); 3) a leguminous GM-containing system (hairy vetch-tomato-soybean-tomato, Hv-To-Sb-To); 4) a graminaceous GM-containing system (rye-tomato-sudan grass-tomato, Ry-To-Sd-To); and 5) system mixed with leguminous and graminaceous GMs (rye-tomatosoybean- tomato, Ry-To-Sb-To). Here, hairy vetch and rye were cultivated as winter cover crops during late $Dec{\sim}late$ Feb and soybean and sudan grass were cultivated as summer cover crops during late $Jun{\sim}mid$ Aug. All of them cut before tomato planting and then incorporated into soil. Biomass of GMs was greater in summer season than that of winter season. Nitrogen amount fixed by a leguminous plants was about $126\;kg\;ha^{-1}$ per a cropping season, corresponding to 60% N level needed for tomato production, which was comparable to 50 and $96\;kg\;ha^{-1}$ fixed by rye and sudan grass. As a result, tomato yield of Hv-To-Sb-To system (legume GM treatment) was similar to Cf-To-Cf-To (conventional), but that in Ry-To-Sd-To system (graminaceous GM treatment) was not attained to a half level of conventional treatment. Nutrient budgets for N, P and K on the conventional farm were balanced or somewhat positive exception for minus-balanced K. Ry-To-Sd-To system showed a positive N, P and K budgets due to the depressed growth of tomato which is caused by high C/N ratio and low N-fixing capacity of the GMs. Inversely, those of Hv-To-Sb-To system were negative in all of N, P and K budgets because of increased growth and yield of tomato with high nitrogen-supplying capacity as well as low C/N ratio of leguminous GM. In conclusion, although conventional cultivation has an advantage in relation to N, P and K nutrient budgets rather than GM-incorporated systems, a leguminous GMs could be recommended as nitrogen reservoir and soil amendment because the yield of tomato between use of leguminous GM and conventional cultivation was not only significantly difference, but also GMs commonly reduce nutrient loss and improve microbial communities.

• Journal of Environmental Impact Assessment
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• v.26 no.6
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• pp.553-562
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• 2017

In these days, agricultural reservoirs are considered as a useful resource for recreational purposes, tour and cultural amenity for vicinity communities as well as irrigation water supply. However, many of the agricultural reservoirs are showing a eutrophic or hyper-eutrophic state and high level of organic contamination. In particular, about 44.7% of the aged agricultural reservoirs that constructed before 1945 exceed the water quality criteria for irrigational water use. In addition to external loading, internal nutrient loading from bottom sediment may play an important role in the nutrient budget of the aged reservoirs. The objectives of this study were to characterize variations of thermal structure of a shallow M reservoir (mean depth 1.7 m) and examine the potential of internal nutrient loading by continuous monitoring of vertical water temperature and dissolved oxygen (DO) concentration profiles in 2015 and 2016. The effect of internal loading on the total loading of the reservoir was evaluated by mass balance analysis. Results showed that a weak thermal stratification and a strong DO stratification were developed in the shallow M Reservoir. And, dynamic temporal variation in DO was observed at the bottom of the reservoir. Persistent hypoxic conditions (DO concentrations less than 2 mg/L) were established for 87 days and 98 days in 2015 and 2016, respectively, during the no-rainy summer periods. The DO concentrations intermittently increased during several events of atmospheric temperature drop and rainfall. According to the mass balance analysis, the amount of internal $PO_4-P$ loading from sediment to the overlying water were 37.9% and 39.7% of total loading during no-rainy season in 2015 and 2016, respectively on August when algae growth is enhanced with increasing water temperature. Consequently, supply of DO to the lower layer of the reservoir could be effective countermeasure to reduce nutrient release under the condition of persistent DO depletion in the bottom of the reservoir.

• Food Science and Preservation
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• v.24 no.8
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• pp.1129-1137
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• 2017

The fringe tree, Chionanthus retusus (Oleaceae) has been used as a natural remedy that helps a paralytic stroke, dementia, phlegm and malaria. This study was conducted to investigate the antioxidant and anti-aging activities of water extracts obtained from the flesh of C. retusus by reflux extraction at room temperature and $80^{\circ}C$, and pressure heating extraction at $110^{\circ}C$, for an increment of their practical use. The highest extraction yield from the flesh of C. retusus was 67.94% extract by pressure heating extraction at $110^{\circ}C$. The content of total polyphenol compounds was the highest by 72.71 mg/g in $80^{\circ}C$ extract by reflux extraction. The highest content of total flavonoid compounds was 7.60 mg/g at $110^{\circ}C$ extract. The results of soluble protein and reducing sugar contents showed the highest content of 4.93 mg/g and 46.77 mg/g in $110^{\circ}C$ extract, respectively. In the analysis of DPPH radical scavenging activity, all extracts showed an excellent effect of 92% in 1.0 mg/mL concentration. The highest effect of ABTS radical scavenging activity was 88.67% at $110^{\circ}C$ extraction in 1.0 mg/mL concentration. Nitrite scavenging ability was the highest as 66.16% at $110^{\circ}C$ extract at pH 1.2 and 1.0 mg/mL concentration. The results of SOD-like activity and xanthine oxidase inhibition activities showed the highest effect of 14.95% and 59.45% at $110^{\circ}C$ extract in 1.0 mg/mL, respectively. Tyrosinase inhibition activity for whitening effect was the highest of 35.31% at $85^{\circ}C$ in 1.0 mg/mL. In the analysis of anti-aging effect, collagenase and elastase inhibition activity showed the highest effects of 37.78% at $110^{\circ}C$ and 20.39% at $80^{\circ}C$, respectively. All results of antioxidant activities and anti-aging effects increased along with the concentration increases. These results indicated that the extracts extracted from the flesh of C. retusus at $80^{\circ}C$ and $110^{\circ}C$ have a large amount of useful ingredients, an excellent antioxidant activity, like as DPPH and ABTS radical scavenging activity, and anti-aging effects to develop functional products than those of $25^{\circ}C$.

• Korean Journal of Health Education and Promotion
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• v.4 no.2
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• pp.32-45
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• 1987

This research attempted to identify basic data related to the nursing of teenagers that would aid in the establishment of nursing care that would meet their health needs, and further to identify which health related activities, are carried out by teenagers, so that appropriate nursing service and health care can be planned for them. The subjects of the study were students at one seoul boys high school and one seoul girls high school. Data was collected between December 16 and. December 19, 1986. The tool used in the study was a questionnaire about the health needs and concerns of teenagers developed at John's Hopkins University and translated and standardized for Korean students. The date was coded fer analysis using' the SPSS program and percentages, mean scores' with standard deviations, Chi square test, and ANOVA, were used for analysis. The following results were obtained : 1. The health status of teenagers : Looking at the health status of teenagers, it can be seen from this study that over half of the teenagers questioned replied that they do not get enough sleep, further that even though they are feeling sick they go to school. However, when asked what they thought of their health, the majority replied that they were healthy, and although they thought about their bea1th was not a concern when they were planning other activities. With regard to health status, there was a significant difference between male and female students concerning whether they were handicapped with regard to sleep, their opinion about their own health, and the amount of time lost from school for illness over the past month, whether in comparison with those of the same age they had more sickeness of not, and whether they had to think about their health when planning other activities. There was also a significant difference according to the age of the students as to whether they worried more about being sick than other members of their age group. 2. Health Realted Activeties of Teenagers : Most of the students in the study reported that they did not get regular physical examinations of health check ups, nor did they get legular examinations when they were sick. Few students reported that they smoked. Most of the students reported taking part in activities that promoted health but about half also reported that they were involved in activities that they knew were detrimental to their health. Further on statistical analysis, there was a significant difference between male and female students regarding health related activities and problems of teenagers and whether they were examined by a medical person when they were sick. 3. The degree of interest and responsibility of teenagers for their own Health: In the section on responsibility for health, the teenagers replies were highest, 4. 5, for the statements, "My health is dependent how much I pay attention to it" and "My health is responsibility" and lowest, 3. 9, for the statement "I am healthy because I have cared for my health so far." With regard to interest in their own health, the majority of the teenagers in the study were more concerned about their studies, high score of 4. 4, than in matters directly related to health. The use of drugs, birth control and masturbation were low on the interest scale. The more involvement in health related activities, the higher the score was for responsibility and this difference was significant, but this did not apply to interest in health. Similarly there was also a significant difference regarding participation in activities known to be detrimental to health and responsiblity for health, but not for interest in health.

• The Korean Journal of Food And Nutrition
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• v.30 no.2
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• pp.226-235
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• 2017

Roselle (Hibiscus sabdariffa L.) is a shrub which grows well in a tropical climate. There are large amounts of anthocyanins, organic acids and other compounds in roselle. Mostly, roselle is cultivated to use its red calyx. Its calyx is used as a natural food colorant and commonly consumed as a tea. This quality study was conducted to investigate the characteristics and antioxidant activities of Sulgidduck with roselle calyx powder. Four samples and a control were made with different ratios of added roselle calyx powder (0.5%, 1%, 1.5%, 2%). The moisture content of the 0.5%-sample was the highest as 40.60%, and that of the 2%-sample was the lowest as 37.37%. The pH of samples significantly decreased from 6.26 to 3.65 as the amount of roselle calyx powder increased (p<0.05). The L-value of samples also significantly decreased (p<0.05). In contrast, a-value and ${\Delta}E$ of samples significantly increased with elevated amounts of roselle calyx powder (p<0.05). The b-value of roselle calyx added Sulgidduck samples significantly increased compared to the control (p<0.05). Hardness and chewiness of Sulgidduck samples with added roselle calyx also significantly increased compared to the control (p<0.05). Cohesiveness of Sulgidduck samples with roselle calyx significantly decreased compared to control (p<0.05), with the exception of the 1% sample. There were no significant differences in springiness among samples. Total phenolic contents significantly increased when roselle calyx powder was added above a level of 1.5% (p<0.05). The flavonoid content of the control was the lowest as 0.73. ABTS radical scavenging activity significantly increased with increasing amounts roselle calyx powder (p<0.05). The 2%-sample got the lowest sensory preference scores in sweetness and overall acceptability. In contrast, the control and 1%-sample got the highest sensory preference scores. Based on these study findings, addition of 1% roselle calyx powder optimized the preparation of Sulgidduck and roselle calyx is therefore a useful natural colorant and antioxidant.

• The Korean Journal of Pesticide Science
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• v.20 no.4
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• pp.305-311
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• 2016

In cultivation environment, various pesticides are used and some of them could be volatilized into the air. This could affect farmer's health and also cause environmental pollution. This study was carried out to investigate the volatilization of pesticides, and use the reference data for preventing farmer's pesticide intoxication and securing worker safety. The experiment was conducted in a greenhouse using a lysimeter which was of $1m^2$ area and 1.5 m depth filled with upland soil. The pesticides treated in lysimeter soil were ethoprophos (5.0% GR), diazinon (34.0% EC), alachlor (43.7% EC), metolachlor (40.0% EC), chlorpyrifos (2.0% GR), pendimethalin (31.7% EC), carbaryl (50.0% WP), napropamide (50% WP), tebuconazole (25.0% WP) and imidacloprid (2.0% GR). Each pesticide was treated at a concentration of 770.5 mg based on A.I (%). The recovery of pesticide ranged from 77.4 to 99.3%. The volatilized pesticides in air were collected by personal air sampler with PUF tube at 4 l/min flow rate. In addition, temperature and humidity were measured. The collected samples were extracted using acetone in a soxhlet apparatus for 8 hours. The extracted pesticides were resoluted with acetonitrile and diluted 5 times. It was analyzed with LC-MS/MS. For 720 hours experiment, the largest vaporization amount of each pesticide in air was ethoprophos $15.24{\mu}g/m^3$, diazinon $5.14{\mu}g/m^3$, pendimethalin $2.70{\mu}g/m^3$, chlorpyrifos $1.76{\mu}g/m^3$, alachlor $1.40{\mu}g/m^3$, metolachlor $1.12{\mu}g/m^3$, carbaryl $0.27{\mu}g/m^3$, napropamide $0.22{\mu}g/m^3$, tebuconazole $0.11{\mu}g/m^3$ and imidacloprid $0.05{\mu}g/m^3$. The R value (coefficient of correlation) between volatilization and vapor pressure of pesticides is higher than 0.99. Therefore, there is high correlation between volatilization and vapor pressure of pesticides.