• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.21-21
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• 2011

A series of Quasi-Elastic Neutron Scattering (QENS) experiments helps us to understand the single-particle (hydrogen atom) dynamics of a globular protein and its hydration water and strong coupling between them. We also performed Molecular Dynamics (MD) simulations on a realistic model of the hydrated hen-egg Lysozyme powder having two proteins in the periodic box. We found the existence of a Fragile-to-Strong dynamic Crossover (FSC) phenomenon in hydration water around a protein occurring at TL=$225{\pm}5K$ by analyzing Intermediate Scattering Function (ISF). On lowering of the temperature toward FSC, the structure of hydration water makes a transition from predominantly the High Density Liquid (HDL) form, a more fluid state, to predominantly the Low Density Liquid (LDL) form, a less fluid state, derived from the existence of a liquid?liquid critical point at an elevated pressure. We showed experimentally and confirmed theoretically that this sudden switch in the mobility of the hydration water around a protein triggers the dynamic transition (so-called glass transition) of the protein, at a temperature TD=220 K. Mean Square Displacement (MSD) is the important factor to show that the FSC is the key to the strong coupling between a protein and its hydration water by suggesting TL${\fallingdotseq}$TD. MD simulations with TIP4P force field for water were performed to understand hydration level dependency of the FSC temperature. We added water molecules to increase hydration level of the protein hydration water, from 0.30, 0.45, 0.60 and 1.00 (1.00 is the bulk water). These confirm the existence of the FSC and the hydration level dependence of the FSC temperature: FSC temperature is decreased upon increasing hydration level. We compared the hydration water around Lysozyme, B-DNA and RNA. Similarity among those suggests that the FSC and this coupling be universal for globular proteins, biopolymers.

• Archives of Reconstructive Microsurgery
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• v.25 no.2
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• pp.37-42
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• 2016

Purpose: Soft tissue coverage of the distal leg and ankle region represents a surgical challenge. Beside various local and free flaps, the perforator flap has recently been replaced as a reconstructive choice because of its functional and aesthetic superiority. Although posterior tibial artery perforator flap (PTAPF) has been reported less often than peroneal artery perforator flap, it also provides a reliable surgical option in small to moderate sized defects especially around the medial malleolar region. Materials and Methods: Seven consecutive patients with soft tissue defect in the ankle and foot region were enrolled. After Doppler tracing along the posterior tibial artery, the PTAPF was elevated from the adjacent tissue. The average size of the flap was $28.08{\pm}9.31cm^2$ (range, 14.25 to $37.84cm^2$). The elevated flap was acutely rotated or advanced. Results: Six flaps survived completely but one flap showed partial necrosis because of overprediction of the perforasome. No donor site complications were observed during the follow-up period and all seven patients were satisfied with the final results. Conclusion: For a small to medium-sized defect in the lower leg, we conducted the close-by islanded PTAPF using a single proper adjacent perforator. Considering the weak point of the conventional propeller flap, this technique yields much better aesthetic results as a simple and reliable technique especially for defects of the medial malleolar region.

• Journal of Nutrition and Health
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• v.46 no.6
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• pp.552-559
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• 2013

This study is conducted in order to investigate the prevalence of vitamin mineral (VM) supplement use and its related factors among Korean adolescents. Using a cross-sectional study design, information was obtained by questionnaires from adolescents selected by stratified sampling in large, small and middle-size cities, as well as rural areas of the whole country, followed by convenience sampling. The total number of participants in this study was 1,407 adolescents ($15.2{\pm}1.6$ years) attending middle or high schools, chosen from various cities and rural areas in Korea. The prevalence of VM supplement use was 65.5%, and there was no significant difference between the genders. City dwellers took VM supplements more frequently than those adolescents from rural areas (p < 0.01). The VM supplement users tended to have higher family income, parents' academic background, and socioeconomic status, respectively (p < 0.001). The greater part of VM supplement users replied that they acquired their nutritional information from their parents, relatives and friends, while many nonusers replied that they did it from school classes (p < 0.05). Compared to nonusers, VM supplement users had greater 'self concern about health' (p < 0.05), 'parents' concern about child's health, growth, and nutritional intake' (p < 0.001), and 'parents' concern about child's grade point' (p < 0.01). However, there was no significant difference between users and nonusers when it came to 'self perception of body shape' or 'BMI'. In addition, users significantly had greater nutritional beliefs concerning VM supplements than nonusers (p < 0.001). These results showed that VM supplement use has been common among adolescents in Korea, and supplement use of subjects has been related with various factors. Among them, it was shown that especially parents great influence the use of VM supplements by adolescents. Thus, not only education for adolescents, but also that for parents is needed to help adolescents take VM supplements properly.

• Journal of Sensor Science and Technology
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• v.27 no.1
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• pp.47-54
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• 2018

In this paper, we describe the thermal characteristics of the output voltages of ethanol gas sensor according to the amount of radiation incident on the infrared sensors located at each focal point of two elliptical waveguides. In order to verify the output characteristics of the gas sensor according to the amount of incident light on the infrared sensor, two combinations of sensor modules were fabricated. Hydrophobic thin film is deposited on one of the reflectors of sensor modules and one of the two infrared sensors was equipped with a hollow disk (10 Ø), and the temperature characteristics of the infrared sensor equipped with the hollow disk (10 Ø) and the infrared sensor without the disk were tested. The temperature was varied from 253 K to 333 K at 10 K intervals based on 298 K. The properties of ethanol gas sensor have been identified with respect to varying temperature for a range of ethanol concentration from 0 ppm to 500 ppm. In the case of an infrared sensor equipped with a hollow disk (10 Ø), the output voltage of the sensor decreased by 0.8 mV and 1 mV, respectively, as the temperature increased. Conversely, the output voltage of the diskless infrared sensor showed an average increase of 67 mV and 57 mV as the temperature increased. The ethanol concentrations estimated on the basis of results show an error of more than 10 % for less than 100 ppm concentration. However, if the ethanol concentration exceeds 100 ppm, the gas concentration can be estimated within the range of ${\pm}10%$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.8
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• pp.1031-1039
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• 2018

If large-scale PV systems are continuously interconnected to distribution system, customer voltages could violate the allowable voltage limit($220{\pm}13V$) according to reverse power flow of PV system. In order to solve these problems, this paper proposes flexible adoption evaluation algorithm of PV system in distribution system which estimates proper introduction capacity and location of ESS(energy storage system) for keeping customer voltages within allowable voltage limit based on various operating scenarios related with connecting point and capacity of PV system. And also this paper proposes modeling of ESS, SVR(step voltage regulator) and PV system using PSCAD/EMTDC S/W and analyzes characteristics of customer voltages and the adoption ability of PV system in distribution system. From the simulation results, it is confirmed that proposed algorithm is useful for large-scale adoption of PV system in distribution system to maintain customer voltages within allowable voltage limit.

• Korean Journal of Veterinary Research
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• v.49 no.1
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• pp.91-99
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• 2009

The concept about zoo is changing from the animal exhibition which simply contained the animals to the ecological zoo which has the function of preserving the animal species. At the central point of maintaining such role, the basic principle called the animal welfare lies obviously. Korea has applied the animal welfare principles such as carrying out the enrichment in the zoos since 2003, but there has not been any institutional device to evaluate and examine the application of the animal welfare so far. This study aims to confirm the level of animal welfare in Korea and suggest a developmental direction. For the purpose of the study, 12 zoos in Korea were evaluated according to 68 evaluating categories. 'Five Principles of Animal Welfare' in the Secretary of State's Standards of Modern Zoo Practice were selected and carried out as the evaluation categories, and the result, from the highest to lowest score given, was 'provision of food and water', 'provision of protection from fear and distress', 'provision of health care', 'provision of an opportunity to express most normal behaviours', and 'provision of a suitable enrichment' with the overall score of the entire Korean zoos being 2.86 (${\pm}$ 0.56). It was also confirmed that in order to improve the animal welfare of the Korean zoos, the animal management system must be standardized and organized. The evaluation and feedback, the active practice of animal welfare and its legislative support should be provided to establish an effective institutional device as well.

• Journal of the Korean Society for Railway
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• v.15 no.2
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• pp.135-140
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• 2012

Interior Permanent Magnet Synchronous motors (IPMSM) with concentrated winding are superior to distributed winding in the power density point of view. But it causes huge amount of eddy current losses on the permanent magnet. This paper presents the optimal permanent magnet V-shape on the rotor of an interior permanent magnet synchronous motor to reduce the core losses and improve the performance. Each eddy current loss on permanent magnet has been investigated in detail by using FEM (Finite Element Method) instead of equivalent magnetic circuit network method in order to consider saturation and non-linear magnetic property. Simulation-based design of experiment is also applied to avoid large number of analyses according to each design parameter and consider expected interactions among parameters. Consequently, the optimal design to reduce the core loss on the permanent magnet while maintaining or improving motor performance is proposed by an optimization algorithm using regression equation derived and lastly, it is verified by FEM.

• Investigative Magnetic Resonance Imaging
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• v.20 no.4
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• pp.207-214
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• 2016

Purpose: The purpose of this study was to investigate the effect of the number of measurement points on the calculation of transverse relaxation time (T2) with a focus on muscle T2. Materials and Methods: This study assumed that muscle T2 was comprised of a single component. Two phantom types were measured, 1 each for long ("phantom") and short T2 ("polyvinyl alcohol gel"). Right calf muscle T2 measurements were conducted in 9 healthy male volunteers using multiple-spin-echo magnetic resonance imaging. For phantoms and muscle (medial gastrocnemius), 5 regions of interests were selected. All region of interest values were expressed as the mean ${\pm}$ standard deviation. The T2 effective signal-ratio characteristics were used as an index to evaluate the magnetic resonance image quality for the calculation of T2 from T2-weighted images. The T2 accuracy was evaluated to determine the T2 reproducibility and the goodness-of-fit from the probability Q. Results: For the phantom and polyvinyl alcohol gel, the standard deviation of the magnetic resonance image signal at each echo time was narrow and mono-exponential, which caused large variations in the muscle T2 decay curves. The T2 effective signal-ratio change varied with T2, with the greatest decreases apparent for a short T2. There were no significant differences in T2 reproducibility when > 3 measurement points were used. There were no significant differences in goodness-of-fit when > 6 measurement points were used. Although the measurement point evaluations were stable when > 3 measurement points were used, calculation of T2 using 4 measurement points had the highest accuracy according to the goodness-of-fit. Even if the number of measurement points was increased, there was little improvement in the probability Q. Conclusion: Four measurement points gave excellent reproducibility and goodness-of-fit when muscle T2 was considered mono-exponential.

• Journal of Acupuncture Research
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• v.32 no.1
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• pp.1-11
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• 2015

Objectives : This study was performed to inquire into the protective effects of acupuncture on oxidative stress caused by cadmium accumulation in the kidney. Methods : Sprague-Dawley male($150{\pm}30g$) rats were stabilized for 1 week and divided into 5 groups: normal, control, $LR_3$ acupuncture, $BL_{23}$ acupuncture and sham acupuncture. For three days experimental groups received oral doses of cadmium 2 mg/kg twice a day. Acupuncture was applied bilaterally at each point 10 times for two weeks. The depth of stimulation was 1 mm at right angles and torsion of acupuncture was produced 2 times per second for 1 minute. The kidneys were extracted and weighed after two weeks, and renal function was confirmed through blood urea nitrogen(BUN). We measured reactive oxygen species of the serum and kidney, and compared expression levels of superoxide dismutase(SOD), catalase, glutathione peroxidase(Gpx), nuclear factor erythroid derived 2-related factor 2(Nrf-2), heme oxygenase-1(HO-1), nuclear factor-${\kappa}B$(NF-${\kappa}B)$, cyclooxygenase-2(COX-2), inducible nitric oxide synthase (iNOS), Bax and Cytochrome c. Results : The $LR_3$ acupuncture group and $BL_{23}$ acupuncture group experienced significantly increased kidney weight, and decreased BUN compared to control group. In terms of oxidative stress, the $LR_3$ acupuncture group and $BL_{23}$ acupuncture group experienced significantly reduced reactive oxygen species compared to the control group. Conclusions : The $LR_3$ acupuncture group and $BL_{23}$ acupuncture group experienced showed the effects of antioxidant, anti-inflammatory and apoptosis protection. The $BL_{23}$ acupuncture group was more effective than $LR_3$ acupuncture group.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4161-4164
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• 2012

Density functional MO calculations for the methylsilole anion of $[C_4H_4SiMe]^-$ and methylgermole anion of $[C_4H_4SiMe]^-$ at the B3LYP (full)/6-311+$G^*$ level (GAUSSIAN 94) were carried out and characterized by frequency analysis. The ground state structure for the methylsilole anion and methylgermole anion is that the methyl group is pyramidalized with highly localized structure. The difference between the calculated $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are 9.4 and 11.5 pm, respectively. The E-Me vector forms an angle of $67.9^{\circ}$ and $78.2^{\circ}$ with the $C_4E$ plane, respectively. The optimized structures of the saddle point state for the methylsilole anion and methylgermole anion have been also found as a planar with highly delocalized structure. The optimized $C_{\alpha}-C_{\beta}$ and $C_{\beta}-C_{\beta}$ distances are nearly equal for both cases. The methyl group is located in the plane of $C_4E$ ring and the angle between the E-Me vector and the $C_4E$ plane for the methylsilole anion and methylgermole anion is $2.0^{\circ}$ and $2.3^{\circ}$, respectively. The energy difference between the ground state structure and the transition state structure is only 5.1 kcal $mol^{-1}$ for the methylsilole anion. However, the energy difference of the methylgermole anion is 14.9 kcal $mol^{-1}$, which is much higher than that for the corresponding methylsilole monoanion by 9.8 kcal $mol^{-1}$. Based on MO calculations, we suggest that the head-to-tail dimer compound, 4, result from [2+2] cycloaddition of silicon-carbon double bond character in the highly delocalized transition state of 1. However, the inversion barrier for the methylgermole anion is too high to dimerize.