• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.74-75
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• 2005

ZnO epilayer were synthesized by the pulesd laser deposition(PLD) process on $Al_2O_3$ substrate after irradiating the surface of the ZnO sintered pellet by the ArF(193 nm) excimer laser. The epilayers of ZnO were achieved on sapphire ($Al_2O_3$) substrate at a temperature of $400^{\circ}C$. The crystalline structure of epilayer was investigated by the photoluminescence. The carrier density and mobility of ZnO epilayer measured with Hall effect by van der Pauw method are $8.27{\times}10^{16}cm^{-3}$ and $299cm^2/V{\cdot}s$ at 293 K, respectively. The temperature dependence of the energy band gap of the ZnO obtained from the absorption spectra was well described by the Varshni's relation, $E_g$(T) = 3.3973 eV - ($2.69{\times}10^{-4}$ eV/K)$T_2$/(T + 463 K). The crystal field and the spin-orbit splitting energies for the valence band of the ZnO have been estimated to be 0.0041 eV and 0.0399 eV at 10 K, respectively, by means of the photocurrent spectra and the Hopfield quasicubic model. These results indicate that the splitting of the $\triangle$so definitely exists in the $\ulcorner_6$ states of the valence band of the ZnO. The three photocurrent peaks observed at 10K are ascribed to the $A_1-$, $B_1-$, and $C_1$-exciton peaks for n = 1.

• Journal of Pharmacopuncture
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• v.20 no.1
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• pp.29-35
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• 2017

Objectives: Aging is an unconscious and gradual process that can lead to changes in biological systems. Induction of oxidative stress and apoptosis, hepatotoxicity and neurotoxicity are involved in the aging process. Regarding the antioxidant property of black seed oil, the aim of this study was to evaluate the anti-aging effect of Nigella sativa (N. sativa) oil on d-galactose-induced aging in mice. Methods: For induction of aging, D-galactose (500 mg/kg, subcoutaneously SC) was administrated to male mice for 42 days. Animals were treated with D-galactose alone or with b lack seed oil (0.1, 0.2, 0.5 mL/kg, intraperitoneally (ip)). Additionally, vitamin E (200 mg/kg) was used as a positive control. At the end of treatment, the malondialdehyde (MDA) and the glutathione (GSH) contents in brain and liver tissues were measured. Also, enzymes in serum, including aspartate aminotransferase (AST) and alanine amino transferase (ALT), were determined. The levels of the proteins Bax, Bcl2, caspase-3 (pro and cleaved) in brain and liver tissues were evaluated. Results: Administration of D-galactose (500 mg/kg, SC) for 42 days increased serum levels of ALT and AST, as well as the MDA content, in brain and liver tissues, but decreased the GSH content. Additionally, the levels of apoptotic proteins, including Bax, procaspase-3 and caspase-3 cleaved, were markedly increased. N. sativa oil (0.1 and 0.2 mL/kg) diminished the levels of the biochemical markers ALT and AST. Administration of black seed oil (0.1, 0.2 and 0.5 mL/kg) reduced lipid peroxidation and at doses 0.1 and 0.2 mL/kg significantly recovered the GSH content. The oil decreased Bax/Bcl2 levels and at 0.1 mL/kg down-regulated the expressions of caspase-3 (pro and cleaved) proteins in brain and liver tissues. Conclusion: Through its antioxidant and anti-apoptosis properties, black seed oil exhibited an anti-aging effect in a model of aging induced with D-galactose.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.6
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• pp.976-983
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• 2000

In this paper, Bridcage type RF coils used widely as RF coils for MRI and its applicable type, spiral type RF coil are analyzed and designed using FDTD method. In low tesla (IT, 1.5T) MRI system, several tools have been used for the analysis and design of the RF coils for MRI. This includes, so-called, LC equivalent circuit method for predicting the resonance frequency of the coil and the Biot-Savart law to determine the field distribution within the coil. Both of the circuit analysis and Biot-Savart law are low frequency techniques. Therefore, at high frequency applications, the circuit model approximation breaks down because the coil geometry is a significant fraction of the wavelength. In this paper, we analyzed and designed RF coils for 3T MRI using FDTD method. This method is a full wave analysis and very accurate at low and high frequencies. Also, this RF coils are actually fabricated and FDTD models of RF coils for MRI are proven.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.396-401
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• 2004

In this paper, a 1MW HAWT(FIL-1000) rotor blade has been designed by BEMT(Blade Element Momentum Theory) with Prandtl's tip loss. Also, a 3-D flow and performance analysis on the FIL-1000 rotor blade has been carried out by using the 3-D Navier-Stokes commercial solver (CFX-5.7) to provide more efficient design techniques to the large-scale HAWT engineers. The rated power and itsapproaching wind velocity at design point (TSR=7.5) are 1MW and 9.99m/s respectively. The rotor diameter is 54.5m and the rotating speed is 26.28rpm. Airfoils such as FFA W-301, DU91-W-250, DU93-W-210, NACA 63418, NACA 63415 consist of the rotor blade from hub to tip. Recent CFX version, 5.7 was adopted to simulate 3-D flow field and to analyze the performance characteristics of the rotor blade. Entire mesh node number is about 730,000 and it is generated by ICEM-CFD to achieve better mesh quality The predicted maximum power occurringat the design tip speed ratio is 931.45kW. Approaching to the root, the inflow angle becomes large, which causesthe blade to be stalled in the region. Therefore, k-$\omega$ SST turbulence model was used to predict the quantitative flow information more accurately. Application of commercial CFD code to optimum blade design and performance analysis was proved to be more effective environment to HAWT blade designers.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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• pp.389-392
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• 2015

We identify a strong lensing galaxy in the cluster IRC 0218 that is spectroscopically confirmed to be at z = 1.62, making it the highest-redshift strong lens galaxy known. The lens is one of the two brightest cluster galaxies and lenses a background source galaxy into an arc and a counterimage. With Hubble Space Telescope (HST) grism and Keck/LRIS spectroscopy, we measure the source redshift to be $z_S=2.26$. Using HST imaging, we model the lens mass distribution with an elliptical power-law profile and account for the effects of the cluster halo and nearby galaxies. The Einstein radius is $^{\theta}E=0.38^{+0.02{\prime}{\prime}}_{-0.01}$ ($3.2^{+0.2}_{-0.1}kpc$) and the total enclosed mass is $M_{tot}(<^{\theta}_E)=1.8^{+0.2}_{-0.1}{\times}10^{11}M_{\odot}$. We estimate that the cluster environment contributes ~ 10% of this total mass. Assuming a Chabrier IMF, the dark matter fraction within $^{\theta}E$ is $f^{Chab}_{DM}=0.3^{+0.1}_{-0.3}$, while a Salpeter IMF is marginally inconsistent with the enclosed mass ($f^{Salp}_{DM}=-0.3^{+0.2}_{-0.5}$).

• Restorative Dentistry and Endodontics
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• v.26 no.1
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• pp.41-50
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• 2001

The purpose of this study was to examine the influences of camphoroquinone on the properties of five experimental composites. The contents of camphoroquinone were varied as 0.2%, 0.3%, 0.4%, 0.5%, and 0.6%, with silanized filler 75% and tertiary amine 0.2%. Five kinds of experimental composites were prepared, and diametral tensile strength, shear bond strength, depth of cure and yellowish discoloration were tested as a measurement. Specimen numbers of 10 were applied to all test items and experimental groups. Specimens for testing the diametral tensile strengths with internal diameter of 6mm in diameter and 3mm in height were filled with 5 experimental composites which were crushed with 1mm/min cross-head speed on Instron universal testing machine (Model No. 4467). Shear bond strength was measured on specimens attached to bovine teeth enamel etched with 37% phosphoric acid. Depth of cure was measured by the measurement of height of specimens which were removed the un-polymerized portion with acetone. Yellowness measurements were made by chromometer(Minolta Co. Japan) using L$^*$a$^*$b$^*$ values. ANOVA and Multiple range tests were used analyzed data with confidence level at 95%. The mean value of the shear bond strengths ranged from 31.03MPa to 39.49MPa. Following results were obtained ; 1. Diametral tensile strength was highest in experimental group 3, then was not affected by the contents of camphoroquinone ($r^2$=0.0422). 2. Composite resins containing 0.4% camphoroquinone showed the highest shear bond strength, but there was no statistical significance (p=0.3718). 3. Camphoroquinone reduces the depth of cure in the composite resins (p=0.0004, $r^2$=0.9483). 4. Camphoroquinone made the composites yellowish ($r^2$=0.9815). These results mean that increased content of camphoroquinone reduces the depth of cure, and that camphoroquinone make composites yellowish.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.3
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• pp.714-720
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• 2007

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by inflammatory cell infiltration in the skin. This study was performed to assess the therapeutic effects of BHOSB on the DNCB-induced dermatitis in NC/Nga mice, characterized by the onset of AD along with an increase the number of inflammatory cells and dysregulation of inflammatory mediators including cytokines and chemokines. BHOSB administration significantly reduced clinical dermatitis severity including pruritus, edema, eczematous and erythema. Histological findings indicated that the thickening of epidermis/dermis and dermal infiltration of inflammatory cells including mast cells were dramatically reduced. The suppression of dermatitis by BHOSB was accompanied by a decrease in the number of CD11b$^+$/Gr-1$^+$ immune cells in skin but not CD3$^+$/CCR3$^+$ cells. However, the number of CD3$^+$ cells was increased in BHOSB administrated NC/Nga mice. Oral administration of BHOSB significantly reduced the level of IL-6, TNF-a and eotaxin 2 mRNA in skin. These data suggest that BHOSB may be effective therapeutic agents for the treatment of AD.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.369-375
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• 2004

Gas turbine engine simulation in terms of transient, steady state performance and operational characteristics is complex work at the various engineering functions of aero engine manufacturers. Especially, efficiency of control system design and development in terms of cost, development period and technical relevance implies controlling diverse simulation and identification activities. The previous engine simulation has been accomplished within a limited analysis area such as fan, compressor, combustor, turbine, controller, etc. and this has resulted in improper engine performance and control characteristics because of limited interaction between analysis areas. In this paper, we propose a new simulation methodology for gas turbine engine performance analysis as well as its digital controller to solve difficulties as mentioned above. The novel method has particularities of (ⅰ) resulting in the integrated control simulation using almost every component/module analysis, (ⅱ) providing automated math model generation process of engine itself, various engine subsystems and control compensators/regulators, (ⅲ) presenting total sophisticated output results and easy understandable graphic display for a final user. We call this simulation system GT3GS (Gas Turbine 3D Graphic Simulator). GT3GS was built on both software and hardware technology for total simulation capable of high calculation flexibility as well as interface with real engine controller. All components in the simulator were implemented using COTS (Commercial Off the Shelf) modules. In addition, described here includes GT3GS main features and future works for better gas turbine engine simulation.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.2
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• pp.501-506
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• 2015

Background: To evaluate the effectiveness of the National Train-the-Trainers Program for Hospice and Palliative Care Experts (TTHPC) sponsored by the National Cancer Center of Korea between 2009 and 2012. This program was developed to improve the teaching skills of those in the field of hospice and palliative care (HPC). Materials and Methods: Training was offered in eight 1-day sessions between 2009 and 2012. The effect of the program was measured using Kirkpatrick's model of educational outcomes. First, levels 1 and 2 were evaluated immediately after the 1-day program (n=120). In 2012, the level-3 evaluation test was administered to trainers who offered at least one HPC training (n=78) as well as to their trainees (n=537). Results: The level-1 evaluation addressed participant reactions to and satisfaction with the program. Participants (n=120) were generally satisfied with the content, the method, and the overall course (mean range: 3.94-4.46 on a five-point Likert scale). The level-2 evaluation (learning) showed that participants gained knowledge and confidence related to teaching HPC (4.24 vs. 4.00). The level-3 evaluation (behavioral), which assessed trainers' application of teaching skills to HPC, showed that trainees rated the teaching methods of trainers (mean range: 4.03-4.08) more positively than did trainers (p<0.05). Female trainers were more likely than were male trainers to plan sessions in consideration of their trainees' characteristics (4.11 vs. 3.58; p<0.05), and nurse trainers were more likely than physician trainers to use a variety of instructional methods (4.05 vs. 3.36; p<0.05) Conclusions: We conducted systematic evaluations based on Kirkpatrick's model to assess the effectiveness of our train-the-trainers program. Our educational program was practical, effective, and followed by our HPC experts, who needed guidance to learn and improve their clinical teaching skills.

• Transactions of the Society of Information Storage Systems
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• v.8 no.2
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• pp.72-77
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• 2012

The demand for the laptop computer has been increased day by day and most of users ask quiet computer and devices to work in comfortable environment. One of the devices which generate acoustic noise is an external ODD. Unlike the internal ODD, the external ODD is easy to emit noise because it runs outside of the computer and also it is packed with a thin plastic covers. As the disk rotates, vortex flow is generated inside of the cavity due to various and complicated mold parts of the cover. In addition, there is a gap between the disk tray and the upper/lower cases, through which the air flows as well as the noise leaks. In this study, we have proposed how to reduce the acoustic noise of an external ODD using numerical and experimental analysis. The pressure fluctuations and turbulent kinetic energy distributions are calculated for the developed model. The results show that the sound pressure level is reduced by 2.3dB through simple modifications of ribs of the top cover, which remove or suppress flow instabilities inside of the cavity.