• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.197.1-197.1
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• 2014

VO2 has intensively investigated for several decades due to its interesting physical properties, including metal-insulator transition (MIT), thermochromic and thermoelectric properties, near the room temperature. And also gas and photo sensing properties of VO2 nanowires have attracted increasing research interest due to the high sensitivity and multi-sensing capability. We studied the light-induced resistance change of VO2 nanowires. In particular, we have investigated plasmonic enhancement of the photo-sensing properties of the VO2 nanowires. To select proper wavelength, we performed finite-difference time-domain simulations of electric field distribution in the VO2 nanowires attached with Ag nanoparticles. Localized surface plasmon resonance (LSPR) is expected at wavelength of 560 nm. The photo-sensitivity was carefully examined as a function of the sample temperature. In the presentation, we will discuss physical origins of the photo-induced resistance change in VO2.

• Journal of the Korean Magnetics Society
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• v.10 no.1
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• pp.22-29
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• 2000

The effective linewidth was measured using the conventional cavity perturbation method at 9.43 GHz in room temperature for Ca-Zr substituted yttrium iron garnet plate. The experimental set-up consists of the network analyzer, the electromagnet and the cylimdrical TE001 cavity. Measurement was performed in the static magnetic field perpendicular to the sample plane. The real and imaginary parts of diagonal component of the microwave susceptibility tensor are obtained from the resonance frequency and the quality factor Q of the cavity. Variations of the effective linewidth was qualitatively explained with the spin wave scattering theory.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.81-86
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• 2005

This study has investigated radiation degradation of low density polyethylene(LDPE). Samples were irradiated up to 800kGy using a $Co^{60}\;\gamma-ray$ at a dose rate of 5kGy/hr in the presence of air atmosphere at room temperature. After irradiation, storing for 2 weeks, free radical measurement of LDPE has established by electron spin resonance(ESR). ESR measurement showed that free radical concentration(FRC) was increased with radiation dose and decreased with the time. The radical types showed alkyl, allyl, and peroxy radical with the irradiation, these changed to peroxy radical with the time.

• Korean Journal of Cleft Lip And Palate
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• v.8 no.2
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• pp.95-105
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• 2005

Cleft lip and palate is a congenital deformity which needs a professional and consistent management from the birth and along with the physical growth of patients. The patients with cleft lip and palate can have general speech problems with resonance disorders, voice disorders and articulation disorders after the successful primary surgical management and the physical growth. Speech problems of Cleft lip and palate are characterized hypernasality, nasal air emission, increased nasal air flow, and aberrant speech marks which decrease intelligibility. These speech problems of cleft lip and palate can be treated with the secondary surgical procedure, the application of temporary prosthesis and the effective and well-timed speech therapy. The speech and language problems of cleft lip and palate, the general procedures and schedules of the speech assessment and therapy based on the multidisciplinary approach are introduced for the patients with cleft lip and palate, their family and the other members of the cleft palate treatment team.

• Journal of Korean Neurosurgical Society
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• v.48 no.6
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• pp.544-546
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• 2010

Paraplegia following spinal epidural anesthesia is extremely rare. Various lesions for neurologic complications have been documented in the literature. We report a 66-year-old female who developed paraplegia after left knee surgery for osteoarthritis under spinal epidural anesthesia. In the recovery room, paraplegia and numbness below T4 vertebra was checked. A magnetic resonance image (MRI) scan showed a spinal thoracic intradural extramedullary (IDEM) tumor. After extirpation of the tumor, the motor weakness improved to the grade of 3/5. If a neurologic deficit following spinal epidural anesthesia does not resolve, a MRI should be performed without delay to accurately diagnose the cause of the deficit and optimal treatment should be rendered for the causative lesion.

• Journal of the Korean Ceramic Society
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• v.28 no.3
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• pp.179-188
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• 1991

The semiconducting BaTiO3 ceramics used in this study were sintered in the reducing atomosphere(hydrogen gas) and neutral atmosphere(nitrogen gas), then were heat-treated in air to vary defect concentrations. In this experiment, the correlations between the composition analysis and electrical characteristics of these samples were investigated. When the BaTiO3 ceramics were sintered in N2 atmosphere, it was observed that the Ba contents near the interface were lower than that of the grain center, and these samples showed superior PTCR effects. From analysis of the resistivities of grains and grain boundaries by CIRM(Complex Impedance Resonance Method), it was confirmed that the PTCR effects were caused by the resistivity of grain boundaries. And from measurement of the capacitance at each temperature, the samples sintered in N2 atmosphere show the increase of room temperature resistance and the decrease of capacitance as a result of the increase of the charge depletion layers. This phenomenon agrees well with the cation deficiencies in the analytical results.

• Tuberculosis and Respiratory Diseases
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• v.40 no.4
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• pp.353-356
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• 1993

Advent of new imaging modalities such as computed tomography, magnetic resonance imaging and ultrasound contributed greately to the specific imaging diagnosis. However plain chest X-ray is still most prequently used for imaging diagnosis of respiratory disease in clinical pratic and it is important to make a good quality of X-ray film and good interpretation. The optimal chest X-ray should be taken with full inspiration without rotation and motion and the exposure is at the level of barely demonstrable thoracic vertebral disc space. It is recommended that higk KVP technique for detection of lesions which is overlaped by mediastinum, heart and rib cage. It is better to examine chest X-ray film start at some distance(6-8 feet) and closer to the film later on and the reader should not read a film in fatigue condition. The reading room should be quiet and relately dark illumination. It is important, to make a good X-ray film and good interpretation to reduce the observer error.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.69-70
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• 2008

Micro resonators have been actively investigated for bio/chemical sensors and RF M/NEMS devices. Among various materials, SiC is a very promising material for micro/nano resonators since the ratio of its Young's modulus, E, to mass density, $\rho$, is significantly higher than other semiconductor materials, such as, Si and GaAs. Polycrystalline 3C-SiC cantilever with different lengths were fabricated using a surface micromachining technique. Polycrystalline 3C-SiC micro resonators were actuated by piezoelectric element and its fundamental resonance was measured by a laser vibrometer in air and vacuum at room temperature, respectively. For the cantilever with $100{\mu}m$ length, $10{\mu}m$width and $1.3{\mu}m$ thickness, the fundamental frequency appeared at 147.2 kHz.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.331-334
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• 1998

The solid solutions of the Pb(Sc$\_$0.5/Nb$\_$0.5/)$\_$0.57/Ti$\_$0.43/O$_3$ system were prepared. In the PSNT system, it had been known that two-phase region between the rhombohedral and tetragonal phases was observed between 0.425 of PT at room temperature. In this paper, Fe$_2$O$_3$-doped 0.57PSN-0.43PT composition was prepared by conventional method. The dielectric and strain properties were examined using an computerized measuring apparatus, and the resonance characteristics were measured using an impedance gain phase analyzer. We got the data of dielectric constant, dielectric loss, piezoelectric coefficient, piezoelectric voltage coefficient, frequency constant strain constant mechanical quality factor and electromechanical coupling factor.

• Current Optics and Photonics
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• v.1 no.5
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• pp.544-550
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• 2017

This simulation based study reports a novel tunable, compact, room temperature terahertz (THz) transistor source, operated on the concept of charge plasma oscillation with the capability of radiating within a terahertz gap. A vertical cavity with a quasi-periodic distributed-Bragg-reflector has been attached to a THz plasma wave transistor to achieve a monochromatic coherent surface emission for single as well as multi-color operation. The resonance frequency has been tuned from 0.5 to 1.5 THz with the variable quality factor of the optical cavity from 5 to 290 and slope efficiency maximized to 11. The proposed surface emitting terahertz transistor is able to satisfy the demand for compact solid state terahertz sources in the field of teratronics. The proposed device can be integrated with Si CMOS technology and has opened the way towards the development of silicon photonics.