• Journal of radiological science and technology
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• v.37 no.4
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• pp.273-278
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• 2014

Bone density measurement use of diagnosis of osteoporosis and it is an important indicator for treatment as well as prevention. But errors in degree of precision of BMD can be occurred by status of patient, bone densitometer and radiological technologist. Therefore the author evaluated that how BMD changes according to the condition of the patient. As Lumbar region, which could lead to substantial effects on bone density by diverse factors such as the water, food, intentional bowels. We recognized a change of bone mineral density in accordance with the height of the water tank and in the presence or absence of the gas using the Aluminum Spine Phantom. We also figured out the influence of bone mineral density by increasing the water and food into a target on the volunteers. Measured bone mineral density through Aluminum Spine Phantom had statistically significant difference accordance with increasing the height of water tank(p=0.026). There was no significant difference in BMD according to the existence of the bowl gas(p=0.587). There was no significant difference in a study of six people targeted volunteers in the presence or absence of the food(p=0.812). And also there was no significant difference according to the existence of water(p=0.618). If it is not difficult to recognize the surround of bone in measuring BMD of lumbar bone, it is not the factor which has the great effect on bone mineral density whether the test is after endoscopic examination of large intestine and patient's fast or not.

• Economic and Environmental Geology
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• v.39 no.5 s.180
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• pp.525-535
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• 2006

A study on stream-groundwater exchange was performed using head and temperature data of stream water, streambed, and groundwater. Groundwater level and temperature were obtained from multi-depth monitoring wells in small-scale watershed. During the summer and winter season, time series of temperature data at streambed and groundwater were monitored for six months. In the winter time, we measured the temperature gradient between stream water and streambed. The observed data showed three typical types of temperature characteristics. First, the temperature of streambed was lower than that of stream water; second, the temperature of streambed and stream water was similar; and the last, the temperature of streambed was higher than that of stream water. The interconnections between the stream and the streambed were not homogeneously distributed due to weakly developed sediments and heterogeneous bedrock exposed as bed of the stream. The temperature data may be used in formal solutions of the inverse problems to estimate groundwater flow and hydraulic conductivity.

• The Journal of Engineering Geology
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• v.22 no.2
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• pp.195-205
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• 2012

We evaluated the results of pumping tests, the amount of groundwater used by Protected Cultivation with Water Curtain (PCWC), and monthly depth to water table (DTW) at the Wangjeon-ri area, Nonsan City, to elucidate the cause of a decrease in pumping rate during the winter PCWC season. The transmissivity and storage coefficient at eight sites where the major aquifer is alluvium, vary from 119.9 to $388.1m^2/d$ and $1.5{\times}10^{-4}$ to $5.5{\times}10^{-4}$, respectively. The pumping rate for PCWC during three months (Dec. to Feb.) averaged about $8,100m^3/d$ and the maximum water level in the area varied by about 10 m. Groundwater levels had fully recovered by August-five months after pumping for PCWC had ceased. These observations indicate that the pumping rate during the winter PCWC season was excessive compared with groundwater productivity in the area. Groundwater level in the central PCWC area varied from -3.0 to 4.38 m, exceeding the water level of the Nosung Stream for only three months (Aug. to Oct.). This result indicates that Nosung Stream recharges the area during the period from November to July. To solve the problem of reduced pumping rate during the winter PCWC season, it would be necessary to reduce the amount of groundwater used for PCWC or to develop an artificial recharge system using recycled groundwater.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.504-508
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• 2011

The objective of this study was to determine the extent to which acetaldehyde (AA) and formaldehyde (FA) migrated from polyethylene terephthalate (PET) bottles into mineral water during storage at 25 and 35$^{\circ}C$ for 240 days. Generally, AA and FA were observed to migrate more at 35$^{\circ}C$ than at 25$^{\circ}C$. The amount of FA in the samples irradiated under UV lamps was higher than in those stored in the dark over the storage period and vice versa for AA. Using a triangular test, the sensory panels distinguished a difference between one sample and the other two mineral water samples that had been exposed to UV lamps after 60 days of storage at 35$^{\circ}C$ (p<0.05). At this time, FA and AA concentrations were measured at 267.4 and 515.3 g/L, respectively. After 120 days, an independent mineral water sample from the other two samples in all treatments could be distinguished by the panel members at a significance level of p<0.001.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.32-41
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• 2004

Analysis of water-level fluctuation due to goundwater-surface water interaction in coastal aquifers is carried out by numerical modeling. The conceptual model used in this study has a stream boundary and a tidal boundary that forms a right angle and the stream partially penetrates the aquifer. We analyzed the effect of each boundary and the simultaneous effect of the two boundary conditions. The area of influence caused by the stream boundary increased during the simulation, while the influence zone of the coastal boundary was relatively constant. The groundwater level near the zone where two boundaries meet may rise by the action of combined effect of the two boundaries or may not change by cancelling the effect of each boundary. Thereafter, care must be taken when hydraulic parameters are estimated using sinusoidal oscillations of hydraulic head in coastal aquifers. Sensitivity analysis is employed to develop insight into the controls on groundwater level fluctuations. In this study our analyses focused on the effect of conductance and the stream width to the aquifer nearby.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.69-73
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• 2007

Inorganic geochemical and mineralogical analyses from the trench sediments of the Hwayang wetland were carried out to verify the wet/dry conditions during 6000 - 5000 yr BP and abnormal event of 6300 yr BP of Korean west coast. Lithostratigraphy, mineralogy and major element concentrations of the sediments of the trench indicate that during 6000 - 5000 yr BP, a wet/dry conditions might be repeated at an interval of 200 years. Carbonate minerals precipitated with the decrease of water depth in the lake or wetland after about 6000 yr BP. On the other hand, the sediments coarser in mean grain size and larger in standard deviation were corresponded with periods of 6300 yr BP and 6230 yr BP. Especially, such a feature of grain size distribution of 6300 yr BP appears in other wetlands situated in the west coast, e.g., Hwangsan wetland and Cheollipo coastal wetland. During the period, the coarse sediments seem to have been delivered by a high energy like storming.

• Journal of Nutrition and Health
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• v.37 no.2
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• pp.100-107
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• 2004

This study was performed to evaluate the effect of dietary protein source and sulfur amino acid content on bone metabolism in ra. Thirty male rats (body weight 145$\pm$2g) were divided into three groups. The rats in the first group were fed on casein 20% diet as animal protein source and those in the second group were fed on soy 20% diet as plant protein source. Sulfur amino acid ratio of these group was 1.07:1. The rats in the third group were fed on soy 20% diet and the sulfur amino acid were supplemented with the amount contained as much in the soy 20% diet. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks, The total body, spine, femur bone mineral density and bone mineral content were measured using Dual Energy X-ray Absorptiometry Calcium, phosphate, pyridinoline, creatinine in urine and calcium, phosphate, alkaline phosphatase, osteocalcin in serum were measured. During the experimental period, plant protein (soy protein) group had a lower urinary Ca excretion, urine pyridinoline ＆ crosslinks value and had a higher Ca efficiency in total bone and femur bone mineral density than animal protein (casein) group. There were no significant differences in serum calcium, phosphate, alkaline phosphatase and osteocalcin among the three groups of the rats. The findings from this study demonstrated that plant protein (soy protein) is beneficial of bone mineral density because it had a higher Ca efficiency in total bone and femur bone mineral density than animal protein (casein). However, the supplementation of sulfur amino acid on soy results were consistent with prior studies that dietary sulfur amino acid load had a negative effect on calcium balance. The rats fed sulfur amino acid supplementation diet increased urinary calcium excretion and decreased calcium efficiency for total and femur mineral density. Therefore, dietary protein source and sulfur amino acid content influence bone metabolism. (Korean J Nutrition 37(2): 100-107, 2004)

• Journal of the Korean Society of Safety
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• v.16 no.1
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• pp.65-72
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• 2001

Portland cement concrete is made with coarse aggregate, fine aggregate, portland cement, water and, in some cases, selected chemical admixture such as air-entraining agents, water reducer, superplasticizer, and so on, and mineral admixture such as fly ash, silica fume, slags, etc. Typically, in the concrete, the coarse aggregate and fine aggregate will occupy approximately 80 percent of the total volume of the finished mixture. Therefore, the coarse and fine aggregates affect to the properties of the portland cement concrete. As the deposits of natural sands have slowly been depleted, it has become necessary and economical to produce crushed sand(manufactured fine aggregate). It is reported that crushed sand differs from natural sands in gradation, particle shape and texture, and that the content of micro fines in the crushed sand affect to the quality of the portland cement concrete. Therefore, the purpose of this paper is to investigate the characteristics of fresh and hardened concrete with higher micro fines. This study provides a firm data to apply crushed sand with higher micro fines.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.285-289
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• 2005

The Cenozoic Era consists of two period , the Tertiary and the Quaternary Period. Weak rock types may include areas containing: 1) poorly cemented or uncemented sediments, 2) highly weathered rock, or 3) fault lines. Especially this paper deal with poorly cemented or uncemented sedimentary rocks in slope. Mechanical weathering is caused by physical processes such as absorption and release of water, and changes in temperature and stress at or near the exposed rock surface. It results in the opening of discontinuities, the formation of new discontinuities by rock fracture, the opening of grain boundaries, and the fracture or cleavage of individual mineral grains. Decomposition causes some silicate minerals such as feldspars to change to clay minerals. There was a strong negative correlation between water absorption and important engineering properties such as strength and durability.

• Journal of Energy Engineering
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• v.27 no.2
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• pp.70-80
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• 2018

Natural organic matter (NOM) is among the most common pollutant in underground and surface waters. It comprises of humic substances which contains anionic macromolecules such as aliphatic and aromatic compounds of a wide range of molecular weights along with carboxylic, phenolic functional groups. Although the concentration of NOM in potable water usually lies in the range of 1-10 ppm. Conventional treatment technologies are facing challenge in removing NOM effectively. The main issues are concentrated to low efficiency, membrane fouling, and harmful by-product formation. Ion-exchangers can be considered as an efficient and economic pretreatment technology for the removal of NOM. It not only consumes less time for pretreatment but also resist formation of trihalomethanes (THMs), an unwanted harmful by-product. This article provides a comprehensive review of ion exchange processes for the removal of NOM.