• Journal of Oral Medicine and Pain
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• 제21권1호
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• pp.183-196
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• 1996

The author examined the clinical and histological changes on the dorsal tongue mucosa of adult Sprague-Dawley rats after lasing by pulsed Nd:YAG laser. The dorsal tongue was lased for 3 seconds by 1.5, 2.0, 2.5, 3.0, 3.5, 4.0W and 10, 15, 20, 20pps. After tissue changes were observed clinically, the excised samples were observed histologically and the width of tissue destruction was analyzed quantitatively under the Confocal laser microscope respectively. The following results were obtained : 1. Whitening of peripheral tissue was observed more as increasing pulsed per second (Hz) below power 2.5W and observed at all parameters above power 3.0W. 2. Charring of mucosal surface was observed at all parameters but mild at parameters below power 2.0W. 3. The destruction of epithelium was observed at all parameters and tissue destruction was extended to lamina propria at higher pulses per second. 4. The width of tissue destruction was more widening as increasing energies per pulse (p<0.001) and the narrowest at 20Hz than 10Hz, 15Hz and 30Hz(p<0.05). As the above results, author suggests power below-3.5W and 20Hz as the lasing parameters for oral soft tissue therapy.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.214-214
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• 2010

The 0.65Pb($Mg_{1/3}Nb_{2/3})O_3-0.35PbTiO_3$ (PMN-PT) thin films with $La_{0.5}Sr_{0.5}CoO_{3-\delta}$ (LSCO) bottom electrodes were grown on $CeO_2$/YSZ/Si(001), Pt/$TiO_2$/Si and $SrTiO_3$ (STO) substrates using conventional pulsed laser deposition (PLD) at a substrate temperature of $550^{\circ}C$. Since generally the crystallographic orientation of the bottom electrode induces the orientation of the films deposited on it, it allows us to observe the influence of the PMN-PT film orientation on the electrical properties. Phi scan done on PMN-PT/LSCO thin films shows epitaxial behavior of the films grown on sto substrates and $CeO_2$/YSZ buffered Si(001) substrates, and (110) texture on Pt/$TiO_2$/Si substrates. Polarization-electricfield (P-E) measurement shows good hysteresis behavior of PMN-PT films with remnant polarization of 18.2, 8.8, and $4.4{\mu}C/cm^2$ on $CeO_2$/YSZ/Si, Pt/TiO2/Si and STO substrates respectively.

• E2M - 전기 전자와 첨단 소재
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• 제7권4호
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• pp.289-293
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• 1994

Thin films of YB $a_{2}$C $u_{3}$$O_{7-x}$ supercondYB $a_{2}$C $u_{3}$$O_{7-x}$uctor were prepared on (100) SrTi $O_{3}$ substrates by pulsed laser deposition using visible light laser. Q-switched Nd:YAG(532 nm, 30 ns) pulsed laser was used for deposition. The effects of substrate temperature and oxygen pressure during deposition on films were studied. Critical current density of 2.93*10$^{6}$ A/c $m^{2}$ at 77K and Tc(zero)=91.7K were obtained from the film prepared with Tsub=745.deg. C and $P_{02}$=200 mTorr. XRD analysis showed that the grown film has c-axis normal orientation to the substrate surface and has single phase. Surface morphology of the film has been improved by interfering the plume ejected from YB $a_{2}$C $u_{3}$$O_{7-x}$ target.arget.t.

• 대한금속재료학회지
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• 제47권6호
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• pp.344-348
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• 2009

Dense $4.25Co_{0.53}Fe_{0.47}-Al_{2}O_{3}$ composite was simultaneously synthesized and consolidated by pulsed current activated combustion method within 2 min from mechanically activated powders. Consolidation was accomplished under the combined effects of a pulsed current and mechanical pressure. Dense $4.25Co_{0.53}Fe_{0.47}-Al_{2}O_{3}$ with relative density of up to 96% was produced under simultaneous application of 80 MPa pressure and the pulsed current. Fracture toughness and hardness of the composite are $6MPa{\cdot}m^{1/2}$ and $570kg/mm^{2}$ respectively.

• 한국재료학회지
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• 제33권6호
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• pp.229-235
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• 2023

An all-perovskite oxide heterostructure composed of SrSnO₃/Nb-doped SrTiO₃ was fabricated using the pulsed laser deposition method. In-plane and out-of-plane structural characterization of the fabricated films were analyzed by x-ray diffraction with θ-2θ scans and φ scans. X-ray photoelectron spectroscopy measurement was performed to check the film's composition. The electrical transport characteristic of the heterostructure was determined by applying a pulsed dc bias across the interface. Unusual transport properties of the interface between the SrSnO₃ and Nb-doped SrTiO₃ were investigated at temperatures from 100 to 300 K. A diodelike rectifying behavior was observed in the temperature-dependent current-voltage (IV) measurements. The forward current showed the typical IV characteristics of p-n junctions or Schottky diodes, and were perfectly fitted using the thermionic emission model. Two regions with different transport mechanism were detected, and the boundary curve was expressed by ln I = -1.28V - 13. Under reverse bias, however, the temperature- dependent IV curves revealed an unusual increase in the reverse-bias current with decreasing temperature, indicating tunneling effects at the interface. The Poole-Frenkel emission was used to explain this electrical transport mechanism under the reverse voltages.

• 대한치과교정학회지
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• 제27권4호
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• pp.623-632
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• 1997

정자기장과 맥동전자기장이 배양 조골세포에 미치는 영향을 알아보고자 MC3T3-E1세포를 각 자기장하에서 배양하여 ALP활성도와 DNA의 합성능을 평가한 결과 다음과 같은 결과를 얻었다. 1. 정자기장을 가한 군에서 자석을 1,2,3개 가한 군($51\~114.8mT$)에서 대조군에 비하여 ALP의 유의성있는 증가가 나타났으며(P<0.05), 자석을 4개 5개 가한 군(150mT)에서는 대조군에 비하여 ALP활성도에 차이가 나타나지 않았다. 2. 맥동성 전자기장에서는 대조군에 비하여 ALP활성도에 유의한 차이가 나타나지 않았다. 3. DNA합성능은 정자기장과 맥동성 전자기장을 가한 군 모두 대조군에 비하여 유의한 차이가 나타나지 않았다. 이상의 결과 정자기장에 의한 교정력은 골세포의 대사과정에 변화를 줄 수 있으므로, 치아이동에 어떠한 영항을 줄 수 있을 것으로 사료된다.

• 한국초전도ㆍ저온공학회논문지
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• 제23권3호
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• pp.41-44
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• 2021

We developed an optimization process of the pulsed laser deposition method to grow epitaxial CeCoIn₅ thin films on MgF₂ substrates. The effects of different deposition parameters on film growth were extensively studied by analyzing the measured X-ray diffraction patterns. All the deposited films contained small amounts of CeIn₃ impurity phase and misoriented CeCoIn₅, for which the c-axis of the unit cell is perpendicular to the normal vector of the substrate surface. The deposition temperature, target composition, laser energy density, and repetition rate were found effective in the formation of (00l)-oriented CeCoIn₅ as well as the undesired phases such as CeIn₃, misoriented CeCoIn₅ along the (112) and (h00). Our results provide a set of deposition parameters that produce high-quality epitaxial CeCoIn₅ thin films with sufficiently low amounts of impurity phases and can serve as a reference for future studies to optimize the deposition process further.

• 한국전자파학회논문지
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• 제26권3호
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• pp.342-348
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• 2015

본 논문에서는 펄스 모드 발진기와 지연선로를 이용하여 새로운 감지 형태를 갖는 버블형 동작감지기를 제안하고, 설계 및 제작하였다. 제안된 동작감지기는 송신 신호의 펄스폭으로 버블 형태의 감지 영역을 형성하며, 지연선로에 의해 시간 지연되는 거리에 해당하는 물체에서 반사된 신호만을 감지하여 IF 신호를 만들어낸다. 제작된 동작감지기는 중심주파수 8 GHz, 펄스 폭 2 nsec, 펄스 주기 30 nsec를 갖는 펄스 모드 발진기를 신호원으로 사용하였으며, 7 nsec와 12 nsec의 지연 시간을 갖는 선로 2개를 사용하여 1 m, 3 m, 5 m의 위치에 버블막 형태의 감지 영역을 성공적으로 형성하여 물체를 감지하였다.

• 대한치과보철학회지
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• 제34권4호
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• pp.800-815
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• 1996

Pulsed Nd : YAG laser has been used to treat various soft tissue lesions. However, there have been warnings of using laser to treat peri-implantitis because the laser can alter the surface of implant and can rise its temperature so that it might be harmful to implant itself and its surrounding tissue. However, the study in vivo has not been done yet. The purpose of this study was to evaluate the biocompatibility to the pulsed Nd:YAG lased dental implant. 16 HA coated implants and 16 titanium plasma sprayed implants were used. They were divided 4 groups as unlased control, 0.3 watt, 1.0 watt and 2.0 watt lased groups after lasing. And they were implanted in the peritonial walls of 12 rabbits. The rabbits were sacrificed 6 weeks after implantation and the LM and EM specimems were made. 1. In the unlased implant group, both HA coated and titanium plasma sprayed implants were surrounded by fibroblasts and collagen fibers. No macrophages and inflammatory cells were seen. 2. In HA coated implants 0.3 watt, 1.0 watt lased group had a little inflammation, but in 2.0 watt lased group had scattered macrophages, a significantly larger number of chronic imflammatory cells were seen. 3. In titanium plasma sprayed implant 0.3 watt, 1.0 watt lased group had a little inflammation, but in 2.0 watt group had severe inflammation as in the conditions of HA coated group. 4. The inflammatory reaction of both lased HA coated and titanium plasma sprayed implant groups increased as the increase of the power of the laser.

• 대한치과보철학회지
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• 제37권2호
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• pp.256-268
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• 1999

Submerged implants require secondary surgical uncovering of implants after healing period of 3-6 months. In surgical methods, there are surgical scalpel, tissue punch, electro-surgical, and laser-used uncovering, and so forth The objectives of this study are investigation and assessment of 1) thermal change in clinical application for uncovering of HA-coated implant and pure titanium implant irradiated by pulsed Nd-YAG, $CO_2$, and Er-YAG laser. 2) surface change of cover screws aaer irradiation using laser energy. The temperature of apex & side wall of implants were recorded at 10sec, 20sec, 30sec after 30sec irradiation to implant healing screw; 1) pulsed Nd-YAG laser; 2W, 20pps, contact mode 2) $CO_2$ laser; water-infused & non-water infused state, 2.5-3.5W, contibuous mode, noncontact mode 3) $CO_2$ laser ; non-water infused state, 3W, superpulse, noncontact. mode 4) Er-YAG laser; (1) non-water infused state, 10pps, 60mj, contact mode (2) water-infused state, 10pps, 60mj, 80mj, 101mj, contact mode. According to the results of this study, pulsed Nd-YAG laser is not indicated because of increased thermal change and pitting of metal surface of implant cover screw. By contrast, $CO_2$ laser & Er-YAG laser are presumed to indicate because of narrow range of thermal change & near abscence of thermal damage of metal surface. Dental laser is thought to be much helpful to surgical procedure when it is used as optimal power and time condition considering characteristics and indications of each laser. Further research is needed to verify that these techniques are safe and beneficial to implant success.