• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.391-392
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• 2008

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.9
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• pp.810-814
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• 2005

[ $Pb(Zr_{0.2}Ti_{0.8})O_3/SrRuO_3$ ] heteroepitaxial thin films were deposited at various temperatures on single crystal $SrTiO_3$ substrates by pulsed laser deposition and characterized for the microstructural and ferroelectric properties. The $SrTiO_3$ substartes etched by buffered oxide etch $(pH{\thickapprox}5.8)$ solution for 20s followed by the thermal annealing at $1000^{\circ}C$ for 1h showed the terrace ledges with a 0.4nm height. The $SrRuO_3$ bottom electrodes with a thickness of 52nm grown on $SrTiO_3$ single crystal also exhibit a terrace ledge similar to that of $SrTiO_3$. The PZT thin films were grown with an epitaxial relationship and showed typical P-E hysteresis loops shown at the epitaxial films. The 56nm thick-PZT films deposited at $650^{\circ}C$ exhibit a remanent polarization $(p_r)$ of $80{\mu}C/cm^2$ and a coercive field $(E_c)$ of 160kV/cm.

• Korean Journal of Metals and Materials
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• v.49 no.7
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• pp.565-569
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• 2011

Nanopowders of MgO, $Al_2O_3$ and $SiO_2$ were made by high-energy ball milling. The fast sintering of nanostructured $Al_2O_3-MgSiO_3-SiO_2$ composites was investigated from mechanically activated powders of MgO, $Al_2O_3$ and $SiO_2$ by a pulsed-current activated sintering process. Nanocrystalline materials have received much attention as advanced engineering materials with improved physical and mechanical properties; in particular greater strength, hardness, excellent ductility and toughness. Highly dense nanostructured $Al_2O_3- MgSiO_3-SiO_2$ composites were produced with simultaneous application of 80 MPa and pulsed output current of 2800A within 2 minutes. The sintering behavior, grain size and mechanical properties of $Al_2O_3-MgSiO_3-SiO_2$ composites were investigated.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.301-312
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• 1997

The purpose of this study was to evaluate the analgesic effect on pulp induced by pulsed Nd : YAG laser according to the power density, irradiated time and the method of application (Non-contact vs contact) in vivo. Experiments were carried out on 90 volunteers who have sound 4 canines. Each canine was grouped by the intensity and the time of irradiation of pulsed Nd : YAG laser was measured. Mean EPT response(units) was measured at 5 min, 30 min, and 60 min after irradiation with various intensity(1.5-3W, 15-30Hz), irradiated time (1.5min, 3min), and application method (Non-contact and contact). The results were as follows: 1. 5 minutes after irradiation, the mean EPT response(units) was increased by 32 % in the non-contact method and by 35% in the contact method of application. Which showed significant difference in mean EPT response(units) compared to not-lased canine in each groups(P<0.05). 2. The mean EPT response(units) with irradiating condition according to the various laser intensity, and the irradiation time stastically did not show significant difference in each groups as time elapsed. 3. There was no significant difference between the non-contact and contact method in the mean EPT response(units). 4. The mean EPT response(units) returned to the baseline value within 30 miuntes. In regard to the above results, the analgesic effect on pulp induced by pulsed Nd : YAG laser resulted a slight increase of pulpal pain threshold, but it was not as high as to replace the role of drug analgesia as whole. This technique can be used for inducing pulpal analgesia as adjunct to other pain control methods and is needed to develop better analgesic effects.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.30.1-30.1
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• 2011

Multiferroic thin films with composition $0.9BiFeO_3-0.1Ba(Cu_{1/3}Nb_{2/3})O_3$ were epitaxially grown by pulsed laser deposition on $SrRuO_3(001)/SrTiO_3$ (000) substrate $0.9BiFeO_3-0.1Ba(Cu_{1/3}Nb_{2/3})O_3$, which is assumed to be morphotropic phase boundary (MPB), that showed superior dielectric, ferroelectric and magnetic properties in our study on polycrystalline films. The structures of epitaxially grown films were characterized by means of XRD. From P-E measurements, samples exhibited typical ferroelectric hysteresis loops and large remnant polarization, whose value is much larger than those of pure BFO film. The enhancement of dielectric, ferroelectric, magnetic properties was attributed to the structural distortion induced by the BCN addition and the high physical stress effect.

• Journal of Sasang Constitutional Medicine
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• v.26 no.1
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• pp.110-121
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• 2014

Objectives The purpose of this study was to report the effects of Korean medical treatment (acupuncture, moxibustion, herb medicine) combined with intense pulsed light (IPL) on three postpartum patients with freckles worsened during pregnancy. Methods and Results The postpartum patients with freckles were treated with acupuncture, moxibustion, herbal medication and IPL. The energy density of IPL was selected modified according to skin types classified by Sasang constitutional medicine. This efficacy of treatment was evaluated with observation. After treatment, freckles as well as various postpartum symptoms are improved. Conclusions This case report shows that the Korean medical treatment combined with IPL is effective in the treatment of postpartum patient's freckles. However further studies are still necessary.

• Nuclear Engineering and Technology
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• v.38 no.8
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• pp.785-792
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• 2006

The microwave heating system of KSTAR consists of ECH and LHCD. ECH and LHCD offer the benefits ofa reliable operation at the start of plasma formation and a non-inductive current drive durable steady state operation, respectively. LHCD uses a C-band microwave system with a frequency of 5 GHz. A pulsed power modulator with a power of 3.6 MW, $4{\mu}S$, 200 pps is required to drive the high-powered magnetron. The development of a pulse modulator with 1:4 pulse transformers is the focus of the research in this study. The peak power handling capability is 3.6 MW (45 kV, 90 A at load side with a pulse width of $4{\mu}S$). This paper describes the system overview and test results of the pulsed modulator. In particular, a simulated waveform is compared with the tested waveform.

• Journal of Magnetics
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• v.17 no.3
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• pp.225-228
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• 2012

Muscle contusion usually results from a direct blunt impact and is frequently associated with contact sports. Muscle contusion results from microscopic muscle fiber and capillary disruption causing a microhemorrhage dissecting torn fibers and remaining viable muscle fibers. Recent studies concluded that some physical methods, including pulsed ultrasound (PU) and pulsed electromagnetic field (PEMF) treatment, accelerate and facilitate wound healing, improve scar quality and have beneficial effects on muscle and tendon healing. However, there are few studies on the effects of the early use of physical methods, such as PU and PEMF, on the expression of neurotrophic factors. The objective of this study was to investigate the effects of the early application of PU and PEMF, measured through the expression of BDNF in the muscles (gastrocnemius) and spinal cords of rats after skeletal muscle contusion. In the spinal cords and muscles, there was a significant increase of BDNF expression in the PEMF and PU groups, a greater increase was found in the PEMF group than in the PU group. In conclusion, PEMF is a useful therapeutic method that improves muscle healing after muscle contusion.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.168-171
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• 2003

Bismuth layered structure, Cerium-substituted $Bi_4Ti_3O_{12}$ ($(Bi,Ce)_4Ti_3O_{12}$) thin films were prepared on the $Pt/TiO_2/SiO_2/Si$ substrates by the pulsed laser deposition method. We investigated the Ce-subsitituted effect on the grain orientation and ferroelectric properties. $Ce^{3+}$ ion substitution for $Bi^{3+}$ ion in perovskite layers of BTO decreased the deeree of c-axis orientation and increased the remanent polariation (2Pr). The structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The $(Bi,Ce)_4Ti_3O_{12}$ (BCT) thin films, which were annealed $700^{\circ}C\;and\;800^{\circ}C$ for 10min and 30min, showed a perovskite phase and dense microstructure. As the thickness of the BCT film was decresed that the ferroelectric properties of the BCT thin films were good.

• Journal of the Korean Vacuum Society
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• v.11 no.3
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• pp.166-170
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• 2002

Artificial $BaTiO_3$(BTO)/$SrTiO_3$(STO) oxide superlattice have been deposited on MgO (100) single crystal substrate by pulsed laser deposition(PLD) method. The stacking periodicity of BTO/STO superlattice structure was varied from $BTO_{1\;unit\; cell}/STO_{1\;unit\; cell}$ to $BTO_{125\;unit\; cell}/STO_{125 \;unit \;cell}$ thickness with the total thickness of 100 nm. The result of X-ray diffraction showed the characteristics of superlattice in the BTO/STO multilayer structure. we have also confirmed that there was no interdiffusion at the interface between BTO and STO layers by high resolution transmission electron microscopy(HRTEM). The dielectric constant of superlattice increased with decreasing stacking periodicity of the BTO/STO superlattice within the critical thickness. The dielectric constant of the BTO/STO superlattice reached a maximum i.e., 1230 at a stacking perioicity of $BTO_{2\;unit\; cell}/STO_{2\;unit\; cell}$ .