• Journal of Life Science
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• v.16 no.6
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• pp.960-963
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• 2006

The purpose of this study is to evaluate the different type of exercise training on the changes of blood variables and leptin in SD rats. For this study, SD rats were divided into three groups: control group (CG: n=10), swim trained group (SG: n=10), and treadmill trained group (TG: n=10). The animals were housed in a pathogen-free animal facility ($22-24^{\circ}C$, 50-60% relative humidity, 08:00-20:00 lighting hours) at D university animal center, Pusan, Korea). Food and water were available ad libitum. The trained rats underwent a 8-wk endurance swim training (5 times/wk) in water at $26-29^{\circ}C$ (SG) and treadmill training (5 times/wk) in DAEJONG treadmill for 60 min. All data were expressed as mean and standard deviation by using SPSS package program (ver 10.0). The result through the statistical analysis of this data were summarized as follows: 1. In the weight changes, there were significant differences among CG, SG and TG(p<.05) after regular swim and treadmill training. TG showed the lowest weight than the other groups. 2. In the epididymal & perirenal adipose tissue levels, there were significant differences among CG, SG and TG(p<.05) after regular swim and treadmill training. TG showed the lowest adipose tissue levels than the other groups. 3. In the triglyceride changes, For the SG and TG, there were significantly decreased after regular swim and treadmill training. TG showed the lowest triglyceride levels than the other groups. 4. In the insulin hormone, For the SG and TG, there were significantly decreased after regular swim and treadmill training. TG showed the lowest insulin levels than the other groups. 5. In the leptin changes, For the SG and TG, there were significantly decreased after regular swim and treadmill training. TG was the lowest than the other groups. Based on the results, Regular swim and treadmill training decrease body weight, epididymal & perirenal adipose tissue levels significantly, this is caused but by decreased triglycerides, insulin, and leptin hormone levels not by the other factors. Regular treadmill training decreased insulin hormone levels compare to swim training, however there was no direct insulin effect on the weight changes. and it might be the direct effect of leptin hormones.

• Journal of The Korean Astronomical Society
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• v.49 no.5
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• pp.199-208
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• 2016

We present photometric results of the δ Sct star V1162 Ori, which is extensively monitored for a total of 49 nights from mid-December 2014 to early-March 2015. The observations are made with three KMTNet (Korea Microlensing Telescope Network) 1.6 m telescopes installed in Chile, South Africa, and Australia. Multiple frequency analysis is applied to the data and resulted in clear detection of seven frequencies without an alias problem: five known frequencies and two new ones with small amplitudes of 1.2-1.7 mmag. The amplitudes of all but one frequency are significantly different from previous results, confirming the existence of long-term amplitude changes. We examine the variations in pulsation timings of V1162 Ori for about 30 years by using the times of maximum light obtained from our data and collected from the literatures. The O − C (Observed minus Calculated) timing diagram shows a combination of a downward parabolic variation with a period decreasing rate of (1/P)dP/dt = −4.22 × 10⁻⁶ year⁻¹ and a cyclic change with a period of about 2780 days. The most probable explanation for this cyclic variation is the light-travel-time effect caused by an unknown binary companion, which has a minimum mass of 0.69 M_⊙. V1162 Ori is the first δ Sct-type pulsating star of which the observed fast period decrease can be interpreted as an evolutionary effect of a pre-main sequence star, considering its membership of the Orion OB 1c association.

• Nuclear Engineering and Technology
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• v.48 no.5
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• pp.1273-1279
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• 2016

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide ($TeO_2$) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gaswelding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ${\leq}10^{-4}mbr.L/s$, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to $600^{\circ}C$ with the appearance of deformations on lids beyond $450^{\circ}C$. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from4 hours of irradiation at a power level of 0.5MWup to 35 hours (7 h/d for 5 days a week) at 1.5MW. The results showthat the irradiated targets are tight because no iodine-131 was released in the atmosphere of the reactor building and in the reactor cooling water of the primary circuit.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.29-37
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• 2016

The type approval system of the railway safety law, which was enforced in 2014, has been preferentially applied to the field of railway vehicles. The type approval system addresses railway vehicles and railway constituents. Unlike the previous system, it requires serial verification stages divided, in consecutive order, into verification of design compatibility and conformity and type test. These stages are in accord with international certification systems including TSI certification of the European commission. This study has been carried out to find and meet the design requirements for a coupler head, which is a part of the automatic coupler system; requirements were drawn from TSI and technical specifications that are subordinate to the domestic railway approval system. Through this study, it has been found that there exist 34 design requirements to acquire a complete coupler head. Among those requirements, 32 were verified by document inspection and two were able to be verified by performing FEA and gathering range analysis data.

• Journal of Chest Surgery
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• v.30 no.11
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• pp.1055-1061
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• 1997

In the field of the experimental lung transplantation, we analyzed the CT findings of acute rejection, infection in the left single allotransplanted lung of adult mongrel dogs, and the CT findings were compared with the histological findings obtained by the lung biopsy Twenty two adult mongrel dogs were divided into two groups(Donor and recipient group). Donor lungs were flushed with LPDG(low pota,ilium dextral glucose) solution(n=4) or modified Euro-collins solution(n=7) and preserved over 20 hours with $10^{\circ}C(1$ case preservation for 4hours). After left single lung transplantation, the chest X-ray and sequential computed tomogram were performed with concomitant hemodynamic study and arterial blood gas analysis on immediate postoperative period, postoperative 3rd day and postoperative 7th day. Two of eleven transplanted lungs had acute rejection which was represented as moderate infiltration at immediate or 1st postoperative d y but became extensive infiltration at postoperative 3rd day on CT. There were showed one case of bronchopleural fistula, six cases of pneumonia and two cases of pulmonary infarction. In one rejection cases, the opacity of transplanted lung was improved by injection of methylprednisolone 500mg daily during 3 days. We concluded that CT was a useful noninvasive evaluation parameter after lung transplantation and the serial CT scan enabled early detection of acute rejection.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.324-333
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• 2013

Recently, rudder erosion due to cavitation has been frequently reported on a semi-spade rudder of a high-speed large ship. This problem raises economic and safety issues when operating ships. The semi-spade rudders have a gap between the horn/pintle and the movable wing part. Due to this gap, a discontinuous surface, cavitation phenomenon arises and results in unresolved problems such as rudder erosion. In this study, we made a rudder model for 2-D experiments using the NACA0020 and also manufactured gap flow blocking devices to insert to the gap of the model. In order to study the gap flow characteristics at various rudder deflection angles($5^{\circ}$, $10^{\circ}$, $35^{\circ}$) and the effect of the gap flow blocking devices, we carried out the velocity measurements using PIV(Particle Image Velocimetry) techniques and cavitation observation using high speed camera in Seoul National University cavitation tunnel. To observe the gap cavitation on a semi-spade rudder, we slowly lowered the inside pressure of the cavitation tunnel until cavitation occurred near the gap and then captured it using high-speed camera with the frame rate of 4300 fps(frame per second). During this procedure, cavitation numbers and the generated location were recorded, and these experimental data were compared with CFD results calculated by commercial code, Fluent. When we use gap flow blocking device to block the gap, it showed a different flow character compared with previous observation without the device. With the device blocking the gap, the flow velocity increases on the suction side, while it decreases on the pressure side. Therefore, we can conclude that the gap flow blocking device results in a high lift-force effect. And we can also observe that the cavitation inception is delayed.

• Journal of Korea Water Resources Association
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• v.48 no.4
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• pp.269-279
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• 2015

Nowadays, the world has suffered by natural disaster of climate change due to global warming. Korea has also faced with similar situation. To prevent these natural disaster, Four Major River Management has conducted. One of conducted content in Four Major River Management is the levee maintenance which classified into fill-up the inland, levee of reinforcement and so on. These maintenances may make the characteristics of groundwater flow change and affect to the levee safety (piping phenomenon). Therefore, analysis on groundwater fluctuation according to level of riverside and inland should be required. This study focus on levee of Hoe stream, which is connected to Nakdong river, and piping safety factor in the levee analyzed by using pore water pressure. Besides, groundwater fluctuation, which is depended on level of riverside and inland, is simulated by using the SEEP/W (2D ground water model). This simulation considered steady flow and unsteady flow. As a result, piping safety factor increased due to rising the inland level. Piping safety factor of riverside was effected by only river water level. Therefore, external levee factor considering inland level raising and suitable control of river water level is need to increase piping safety factor.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.776-781
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• 2006

Perchlorate ion($ClO_4^-$), which is present in the solid propellant for rocket, herbicide and some fertilizers. Perchlorate inhibits iodide uptake by the human thyroid gland. Impairment of thyroid function in expectant mothers may impact the fetus and result in effects including cerebral palsy, give rise to thyroid gland cancer. The US EPA(Environmental Protection Agency) adopted a reference dose(RfD) for perchlorate 0.0007 mg/kg-day, and this guidance lead to a Drinking Water Equivalent Level(DWEL) of 24.5 ${\mu}g/L$. The studies about perchlorate are actively performed in foreign countries, especially in USA but there is no study which surveyed the perchlorate contamination in Korea. Therefore, this study was done to investigate perchlorate contamination in Nak-dong river and tap water. The perchlorate was detected in Nakdong river and ranged from ND to 278.4 ${\mu}g/L$. The highest concentration was observed in Kumichon. The perchlorate concentration was decreased with the down stream of Nakdong river. The perchlorate concentration in tap water was varied with the cities and the concentration levels were $ND{\sim}34.1$ ppb. The highest perchlorate concentration was observed in DalsuGoo in Daegu and the similar concentration($9{\sim}11$ ${\mu}g/L$) was detected in most of the districts in Busan. The result of this study suggests that there is a perchlorate source near the Nakdong river and the urgent policy is needed to control perchlorate for the cities which are supplied from Nakdong river as for their tap water.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.3
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• pp.303-309
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• 2007

Statement of problem. The effect of gold electroforming on gold alloy was not studied. Purpose. This in vitro study investigate the effect of gold electroforming on gold-silver-palladium alloy. Material and methods. Three pieces of gold strips had undergone the electroforming procedures on one side and then half of the side again electroformed. The set mode for this study was program 1 ($200{\mu}m$). And the processing time was 15min (1/20 time to form $200{\mu}m$ coping). The confocal laser scanning microscope (PASCAL 5, Carl Zeiss, Bernried, Germany) was used to measure the thickness of the pure gold layer electroformed on the gold strips. Half of the gold strip was coated two times with electroformed gold, and the other half one time. The data from the cone focal laser system was processed to get the vertical profile of the strips and the difference of the vertical height between the double coated and single coated layer was regarded as the thickness of the gold coating. The layer thickness value to built 3D image of the cone-focal laser was set $0.5{\mu}m$. Next to the measurement of the thickness of the coating, the Vicker's hardness test was done. It was performed on the double coated surface, single coated surface and non-coated surface (back side) three times each. Results. The mean thickness value gained from gold electroforming technique was measured to be $22{\mu}m$ for sample 1, $23{\mu}m$ for sample 2, $21{\mu}m$ for sample 3. In the same condition of time, power and the amount of electrolyte, the data showed no difference between samples. According to the results of variance analysis, the differences among the variations in number of coating were statistically insignificant (p>0.05), meaning that the two times of gold electroforming coating did not change the hardness of gold-silver-palladium alloy. Conclusion. The test of thickness of gold coating proved the coherency of the gold electroforming procedure, in other words, when the power, the exposed surface area, processing time and the amount of electrolytes were set same, the same thickness of gold would be coated on. The hardness test showed that the electroformed gold coating did not change the hardness of the gold-silver-palladium alloy when it is coated not more than $45{\mu}m$.

• Journal of Mushroom
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• v.11 no.3
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• pp.164-170
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• 2013

This study was carried out to compare the medicinal effects of various fruiting body of Ganoderma species and Cordyceps militaris, Phelinus linteus extracts. ${\beta}$-glucan and polyphenol are useful ingredient in mushrooms and they were known to have antioxidant activity. We analyzed ${\beta}$-glucan and polyphenol contents of fruiting body of Ganoderma spp., Cordyceps militaris, and Phellinus linteus. Most Ganoderma spp. exhibited ${\beta}$-glucan contents of 15 to 20%. Cordyceps militalis showed the highest ${\beta}$-glucan level of 25%. Interestingly, eight strains of Ganoderma spp. was analyzed to have higher contents of ${\beta}$-glucan than Phelinus linteus. Polyphenol contents was measured after extraction with different solvents. (D.W., 70% EtOH, 80% MeOH) The level of polyphenol in ASI 7020 strain was at maximum in the water extraction and ASI 7086 showed the highest level in the 70% EtOH extraction. The amounts of polyphenol in strain ASI 7113 was at maximum in the 80% MeOH extraction.