• Journal of radiological science and technology
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• v.40 no.1
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• pp.41-47
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• 2017

Considering that the X-ray apron used in the department of radiology is also used in the department of nuclear medicine, the study aimed to analyze the shielding rate of the apron according to types of radioisotopes, thus ${\gamma}$ ray energy, to investigate the protective effects. The radioisotopes used in the experiment were the top 5 nuclides in usage statistics $^{99m}Tc$, $^{18}F$, $^{131}I$, $^{123}I$, and $^{201}Tl$, and the aprons were lead equivalent 0.35 mmPb aprons currently under use in the department of nuclear medicine. As a result of experiments, average shielding rates of aprons were $^{99m}Tc$ 31.59%, $^{201}Tl$ 68.42%, and $^{123}I$ 76.63%. When using an apron, the shielding rate of $^{131}I$ actually resulted in average dose rate increase of 33.72%, and $^{18}F$ showed an average shielding rate of -0.315%, showing there was almost no shielding effect. As a result, the radioisotopes with higher shielding rate of apron was in the descending order of $^{123}I$, $^{201}Tl$, $^{99m}Tc$, $^{18}F$, $^{131}I$. Currently, aprons used in the nuclear medicine laboratory are general X-ray aprons, and it is thought that it is not appropriate for nuclear medicine environment that utilizes ${\gamma}$ rays. Therefore, development of nuclear medicine exclusive aprons suitable for the characteristics of radioisotopes is required in consideration of effective radiation protection and work efficiency of radiation workers.

• International Journal of Highway Engineering
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• v.11 no.3
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• pp.97-109
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• 2009

One of the main causes of asphalt rutting is high temperature of the pavement. Nevertheless, there has been few research on lowering the pavement temperature for reducing rutting. This study investigated the performance characteristics of moisture-retaining porous asphalt pavement, which is known to have a temperature reducing effect. The purpose of this study is to quantify the temperature reducing effect of moisture-retaining porous asphalt pavement and its effect of reducing rutting through Accelerated Pavement Testing(APT). Additionally, the possibility of reducing the thickness of the pavement in comparison to general dense grade pavement by analyzing structural layer coefficient of moisture retaining pavement. A total of three test sections consisting of two moisture-retaining porous asphalt pavement sections and one general dense-grade porous asphalt pavement section were constructed for this study. Heating and spraying of water were carried out in a regular cycle. The loading condition was 8.2 ton of wheel load, the tire pressure of $7.03kgf/cm^2$, and the contact area of $610cm^2$. The result of this experiment revealed that the temperature reducing effect of the pavement was about $6.6{\sim}7.9^{\circ}C$(average of $7.4^{\circ}C$) for the middle layer and $7.9{\sim}9.8^{\circ}C$(average of $8.8^{\circ}C$) for surface course, resulting in a rutting reduction of 26% at the pavement surface. Additionally, the structural layer coefficient of moisture retaining pavement measured from a laboratory test was 0.173, about 1.2 times that of general dense grade pavement. The general dense-grade porous asphalt pavement test section exhibited rutting at all layers of surface course, middle layer, and base layer, while the test sections of moisture-retaining porous asphalt pavement manifested rutting mostly at surface course only.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.65-73
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• 2008

Because main barley straw management is changing these days from off-fields to burning that may relate to air quality concerning the global warming, this study was conducted to investigate the effects of barley-straw management practices on greenhouse gas emissions during rice cultivation in rice-barley double cropping system. The treatments were barley straw burning, off-field usage of barley straw and incorporation of barley straw in paddy fields. Laboratory experiment showed that burning of barley straw at the rate of $4.5Mg\;ha^{-1}$ emitted GHGs in the amounts of 4,607, 19.5, and $0.9kg\;ha^{-1}$ of $CO_2$, $CH_4$, and $N_2O$, respectively. During the rice cultivation of the rice-barley double cropping system, the highest GHG emission by evaluated close-static chamber method was observed from the soil incorporation of barley straw with 387 and $1.0kg\;ha^{-1}$ of $CH_4$ and $N_2O$, respectively. The GHGs emissions from the barley straw burning and off-field usage treatments were 233 and $160kg\;ha^{-1}$ for $CH_4$ and 0.80 and $0.79kg\;ha^{-1}$ for $N_2O$, respectively. The barley straw burning treatment showed the greatest GHGs emission among barley straw management practices in rice-barley double cropping system when considering GHGs emissions both during burning and from paddy fields during the cropping seasons. As a result, the GHGs emissions recorded in the barley straw incorporation to soil and off-field usage treatments were 22.4 and 66.8%, respectively, less than sum of GHGs emissions from the burning of barley straw and from paddy fields during rice cultivation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.1
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• pp.80-87
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• 2011

Panax ginseng has been used as a traditional medicine for several centuries in Korea. A laboratory experiment using methanol extracts of freeze-dried leaves and roots in the different ages of P. ginseng was conducted to determine the content of phenolics and flavonoids, antioxidant activity and cytotoxicity. The results indicate that the total phenolics level [mg ferulic acid equivalents (FAE) $kg^{-1}$ DW] was higher in leaves (22.0 to 76.3 mg $kg^{-1}$) than roots (19.0 to 28.3 mg $kg^{-1}$) of P. ginseng. The total content of phenolics in roots increased with increase in age of P. ginseng from one to six years. However, the content of phenolics in P. ginseng leaf decreased with the increase in age. Total flavonoid [mg naringin equivalents $kg^{-1}$ DW] was more detected in the leaves (30.3 to 138.6 mg $kg^{-1}$) than in the roots (0.0 to 10.6 mg $kg^{-1}$) of P. ginseng. The total flavonoid level in leaves decreased with increase in age of P. ginseng. The antioxidant potential of the methanol extracts from the plants dose-dependently increased. DPPH free radical scavenging activity was higher in leaves (36.9 to 82.8%) than in roots (14.8 to 39.4%), and in young plants than in old ones. According to 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, the methanol extracts from 5 year-root part showed the highest cytotoxicity against Calu-6, followed by 2 year- and 3 year-roots. However, the methanol extracts from 6 year- and 4 year-roots had lower cytotoxicity. Total phenolics content in both leaves and roots was highly correlated with the DPPH radical scavenging ($r^2=0.7366$ to 0.7870) and nitrite scavenging ($r^2=0.5604$ to 0.8794) activities, suggesting that they contribute to the antioxidant properties of the P. ginseng plants.

• Korean Journal of Environmental Agriculture
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• v.31 no.2
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• pp.104-112
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• 2012

BACKGROUND: Agricultural inputs (fertilizer and organic inputs) and water conditions can influence $CH_4$ and $CO_2$ emission from agricultural soils. This study was conducted to investigate the effects of agricultural inputs (fertilizer and organic inputs) under changing water regime on $CH_4$ and $CO_2$ emission from a soil in a laboratory incubation experiment. METHODS AND RESULTS: Four treatments were laid out: control without input and three type of agricultural inputs ($(NH_4)_2SO_4$, AS; pig manure compost, PMC; hairy vetch, HV). Fertilizer and organic inputs were mixed with 25 g of soil at 2.75 mg N/25 g soil (equivalent to 110 kg N/ha) in a bottle with septum, and incubated for 60 days. During the first 30-days incubation, the soil was waterlogged (1 cm of water depth) by adding distilled water weekly, and on 30 days of incubation, excess water was discarded then incubated up to 60 days without addition of water. Based on the redox potential, water regime could be classified into wetting (1 to 30 days), transition (31 to 40 days), and drying periods (41 to 60 days). Across the entire period, $CH_4$ and $CO_2$ flux ranged from 0 to 13.8 mg $CH_4$/m/day and from 0.4~1.9 g $CO_2$/m/day, and both were relatively higher in the early wetting period and the boundary between transition and drying periods. During the entire period, % loss of C relative to the initial was highest in HV (16.4%) followed by AS (8.1%), PMC (7.5%), and control (5.4%), indicating readily decomposability of HV. Accordingly, both $CH_4$ and $CO_2$ fluxes were greatest in HV treatment. Meanwhile, the lower $CH_4$ flux in AS and PMC treatments than the control was ascribed to reduction in $CH_4$ generation due to the presence of oxidized compounds such as ${SO_4}^{2-}$, $Fe^{3+}$, $Mn^{4+}$, and ${NO_3}^-$ that compete with precursors of $CH_4$ for electrons. CONCLUSION: Green manure such as HV can replace synthetic fertilizer in terms of N input, however, it may increase $CH_4$ emission from soils. Therefore, co-application of green manure and livestock manure compost needs to be considered in order to achieve satisfactory N supply and to mitigate $CH_4$ and $CO_2$ emission.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.469-480
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• 2003

Laboratory leaching experiment study carried out to estimate a extent of heavy metals that could be leached out when acid rain(pH 5.0-3.0) and strong acidic solution(pH 2.5-1.0) reacted with tailings and contaminated soils from abandoned metal mines. In slightly to moderately acid conditions(pH 5.0-3.0), As, Pb and Zn dissolutions became significantly increased with decreased pH in tailing, while dissolution of these elements was very limited in contaminated soil. These results suggested that moderately acid rainwater leaches Pb, As and Zn from the tailings, while these elements would remain fixed in contaminated soil. In the pH range of 2.5-1.0(strongly acid condition), Zn, Cd and Cu concentrations of leachate rapidly increased with decreased pH in contaminated soil, while Pb, As and Co dissolutions became importantly increased in tailings. The experimental solubility of Zn. Cd and Cu was very low even at very low pH values(up to pH 1), except for CY4(Cheongyang mine). These can result from an incomplete dissolution or the presence of less soluble mineral phases. So, the solubility of heavy metals depends not only on the pH values of leachate but also on the speciation of metals associated with contaminated soils and tailings. The relative mobility of each element within failings at the pH 5.0-3.0 of the reaction solution was in the order of Pb>Zn>Cd>Co=Cu>As. In case of pH 2.5-1.0 of the reaction solution, the relative mobility of each element within contaminated soils and tailings were in the order of Zn＞Cd>Cu>Co>Pb=As for contaminated soils, and Pb>Zn>Cd>hs>Co>Cu for tailings. The obtained results could be useful for assessing the environmental effects and setting up the restoration plan in the areas.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.58-65
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• 1977

A laboratory experiment was carried out with loamy paddy soily under Hooded condition to study the effects of some pesticides on the decomposition rate of urea and the transformation of nitrogen. The pesticides used in this study are ten kinds, which are usually applicable for rice cropping. The soil was treated with 200ppm of fertilizer urea-N and different levels of pesticides and then incubated at $28{\pm}1^{\circ}C$ for two weeks. The kinds of pesticides used in this study were three kinds of herbicides (2,4-D, Machete and TOK), three kinds of fungicides (Rabcide, Neo-asozine and Phenazine) at the levels of 20,100 and 200ppm and four kinds of insecticides (Birlane, Diazinon, Sumithion and Bux) at the levels of 50,250 and 500ppm. respectively. The results obtained may be summarized as follows. 1. The treatments of herbicides and fungicides show little effect on the decomposition rate of urea at the levels of 20 and 100ppm, but by the treatment of 200ppm it was retarded markedly after one day incubation aside from Rabcide and Neo-asozine. The decomposing rate of urea was inhibited weakly by the treatment with 250ppm of Sumithion and Bux, however, 500ppm of all kinds of insecticides treated in this study brought about strong inhibitory effect (over 50%) after only one day incubation. The applied urea was disappeared nearly completely in three days in all cases with and without pesticides. 2. The production of ammonium-N was increased with the increase of pesticide concentrations gradually through two weeks and otherwise in the control sample a loss of inorganic-N resulted in about 20% extent. 3. The inhibitory effect of the all applied pesticides on_the_ nitrification under flooded condition was observed markedly and may be ordered as insecticides, herbicides and fungicides according to its inhibiting action.

• Applied Biological Chemistry
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• v.20 no.1
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• pp.88-94
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• 1977

A laboratory study was made of liming on the extractability of phosphate added to the uncultivated acid soils differing in clay content. The experiments were conducted with different rates of calcium carbonate and triple superphosphate at field capacity and 50% field capacity. The concentration of extractable phosphate was greatly reduced by simultaneous addition of calcium carbonate in the loam soil. When samples of the loam soil were preincubated for ranging from 0 to 50 days in the presence of calcium carbonate prior to phosphate application, the extractable phosphate concentration increased with preincubation time, and more phosphate was extracted from the soil maintained at 50% field capacity during the incubation. However, the extractable phosphate concentration in the sandyloam soil did not change with preincubation time and was not affected by moisture status. It may be concluded that the extractability of added phosphate was influenced by not only liming time but physical properties of soil.

• Geophysics and Geophysical Exploration
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• v.15 no.4
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• pp.209-218
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• 2012

Repeatability and reproducibility in solid weight and effective porosity measurements have been discussed using 8 core samples with different diameters, lengths, rock types, and effective porosities. Further, the effect of temperature on the effective porosity measurement has been discussed as well. Effective porosity of each sample has been measured 7 times with vacuum saturation method with vacuum pressure of 1 torr and vacuum time of 80 minutes. Firstly, effective porosity of each sample is measured one by one, so that it can provide a reference value. Then for reproducibility check, effective porosity measurements with vacuum saturation of 2, 4, and 8 samples simultaneously have been performed. And finally, repeated measurements for 3 times for each sample are made for repeatability check. Average deviation from the reference set in solid weight showed 0.00 $g/cm^3$, which means perfect repeatability and reproducibility. For effective porosity, average deviations are less than 0.07% and 0.05% in repeatability and reproducibility test sets, respectively, which are in good agreement too. Most of porosities measured in reproducibility test lies within the deviation range in repeatability test sets. Thus, simultaneous vacuum saturation of several samples has little impact on the effective porosity measurement when high vacuum pressure of 1 torr is used. Air temperature can cause errors on submerged weight read and even effective porosity, because it is closely related to the temperature, density, and buoyancy of water. Consequently, for accurate measurement of effective porosity in a laboratory, efforts for maintaining air or water temperature constant during the experiment, or a temperature correction from other information are needed.

• Journal of dental hygiene science
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• v.17 no.6
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• pp.495-500
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• 2017

Hippophae rhamnoides L. (sea buckthorn) is a shrub wood that belongs to the bamboo tree family, and is rich in vitamin C, D, and E; it is referred to as a vitamin tree. It is mainly grown in the high mountains of Europe and Central Asia, and has been widely used in China and Russia as natural medicine. Recent studies have shown that it is effective in the treatment of cancer, liver diseases, cardiovascular diseases, and gastrointestinal diseases. However, results of studies on its effect on the regulation of pain are insufficient. In this study, we investigated the effect of sea buckthorn on the development and control of pain in two facial areas. The experimental animals included 7- to 8-week-old Sprague-Dawley rats (240~260 g). Formalin (5%), which is known as an inflammation inducer, was injected into the vibrissa pad or temporomandibular joints to induce orofacial acute pain. Rubbing or scraping of the region injected with formalin was regarded as a pain index, and the behavioral response was observed for 45 minutes after the injection. Sea buckthorn extract diluted to 150, 300 mg/kg (in 1 ml of distilled water) was orally administered 30 minutes prior to the acute pain. The facial pain behavior was effectively reduced in the 300 mg/kg group when compared to the control group (vehicle). Likewise, in an experiment in which formalin was injected into the temporomandibular joints, effective pain alleviation was confirmed at the same drug concentration. These results suggest that sea buckthorn extract may be useful in the development of therapeutic agents for acute inflammatory pain in the orofacial area and for controlling temporomandibular joint pain.