• 제목/요약/키워드: Pulsed laser

검색결과 1,239건 처리시간 0.028초

Comparative Analysis of Photoplethysmography under Pulsed Magnetic Field and Low Level Laser Stimulus: Motivation for Blood Flow Increase using Stimulus on Acupoint LI4 (Hegu)

  • Kim, Young Jin;Yoo, Jun Sang;Hwang, Do Guwn;Lee, Hyun Sook
    • Journal of Magnetics
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    • 제19권1호
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    • pp.32-36
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    • 2014
  • The purpose of this study was to investigate the effect of pulsed magnetic field (PMF) and low frequency low level laser (LFLLL) stimuli on acupoint LI4 (Hegu) using photoplethysmography (PPG). Our PMF system was designed to generate maximum intensity of 0.20 T at a transition time of 0.16 ms, with pulse intervals of 1 Hz. The diode laser with wavelength of 650 nm and power of 5 mW was also employed. It was observed the change of the pulsating blood volume through measuring PPG signals from both hands. These results imply that stimulating acupoint LI4 with PMF and LFLLL improves the circulation of peripheral vascular system. In particular, PMF stimulation brings a big improvement of the blood flow even with short term stimulation of 3-4 minutes compared to LFLLL stimulus.

Pulsed laser ablation of hydroxyapatite in ethanol

  • Lee, Jung-Il;Ryu, Jeong Ho
    • 한국결정성장학회지
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    • 제24권5호
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    • pp.219-223
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    • 2014
  • Pulsed laser ablation in liquid medium was successfully employed to synthesize hydroxyapatite colloidal nanoparticles. The crystalline phase, particle morphology, size distribution and microstructure of the hydroxyapatite nanoparticles were investigated in detail. The obtained hydroxyapatite nanoparticles had spherical shape with sizes ranging from 5 to 20 nm. The laser ablation and the nanoparticle forming process were discussed with explosive ejection mechanism by investigating change of surface morphology on target. The analytical results of XPS, FT-IR and Raman spectroscopy confirms that the stoichiometry and bonding properties of the hydroxyapatite nanoparticles are in good agreement with reported bulk hydroxyapatite materials.

Incidental Ignition of a Pulsed Dye Laser Fiber During Laryngomicrosurgery : A Case Report

  • Suh, Yun Suk;Lee, Eun Jung;Kim, Min Ki;Choi, Hong-Shik
    • 대한후두음성언어의학회지
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    • 제27권1호
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    • pp.51-53
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    • 2016
  • Surgical fires require an ignition source, oxidizer, and fuel. The pulsed dye laser (PDL) has been shown to be effective in the treatment of hypertrophic scars and keloids in dermatology. With the increasing number of applications of $CO_2$, laser as ignition source has been associated with operating room fires in the otorhinolaryngologic field. There have been many case reports on PDL-induced fires in dermatology, but until now, there were no reports in the larynx. We describe a 57-year-old patient diagnosed with laryngeal hyperkeratosis treated by PDL-assisted laryngomicrosurgery. In this case, we experienced incidental PDL tip flaring during pulsed dye laser vaporization.

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펄스 레이저 증착법을 이용한 실리콘 박막의 어닐링 온도 변화에 따른 발광 특성연구 (Effect of Annealing Temperature on the Luminescence of Si Nanocrystallites Thin Flms Fabricated by Pulsed Laser Deposilion)

  • 김종훈;전경아;이상렬
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.127-130
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    • 2001
  • Si thin films on p-type (100) Si substrate have been fabricated by pulsed laser deposition technique using a Nd:YAG laser. The pressure of the environmental gas during deposition was 1 Torr. After deposition, Si thin film has been annealed again at 400-840$^{\circ}C$ in nitrogen ambient. Strong blue photoluminescence (PL) have been observed at room temperature. We report the PL properties of Si thin films depending on the variation of the annealing temperature.

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펄스레이저 증착법에서 기판-플룸 각 변화가 ZnO 박막의 구조 및 광학적 특성에 미치는 영향 (Structural and Optical Properties of ZnO Thin Films Grown at Various Plume-Substrate Angles by Pulsed Laser Deposition)

  • 강정석;강홍성;김재원;이상렬
    • 한국전기전자재료학회논문지
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    • 제17권3호
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    • pp.329-332
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    • 2004
  • ZnO thin films were grown with different plume-substrate angles by pulsed laser deposition (PLD) to control the amount of ablated species arriving on a substrate per laser shot. The angles between plume propagation direction and substrate plane (P-S angle) were 0$^{\circ}$, 45$^{\circ}$ and 90$^{\circ}$. The growth time was changed in order to adjust film thickness. From the XRD pattern exhibiting a dominant (002) and a minor (101) XRD peak of ZnO, all films were found to be well oriented along c-axis. From the AFM image, it was found that the grain size of ZnO thin film was increased, as P-S angle decreased. UV intensity investigated by PL (Photoluminescence) increased as P-S angle decreased.

펄스 레이저 증착법에 의한 DLC 박막 제작 연구 (Study on the fabrication of DLC thin films by pulsed laser deposition)

  • 정영식;은동석;이상렬;정해석;박형호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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    • pp.285-287
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    • 1997
  • We have deposited hydrogen-free diamond-like carbon (DLC) films by pulsed laser deposition of graphite. Pulsed laser deposition (PLD) can be utilized to generate films with desired properties quite different from those of the starting material. Since DLC films grown by PLD using turbo pump are perpared without hydrogen, they have a higher density and a higher index of refraction than the hydrogenated DLC films. In this study, effects of the substrate temperature and laser energy density on the properties of DLC films were systematically investigated. The structure and properties of the films have been studied by scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), and Raman spectroscopy.

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레이저를 이용한 하지정맥류 치료의 정량화 연구 (Quantitative Evaluation on Laser Performance for Endovenous Photocoagulation)

  • 안민우;;오정환;강현욱
    • 대한의용생체공학회:의공학회지
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    • 제35권3호
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    • pp.62-67
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    • 2014
  • The purpose of the study was to identify the effect of laser parameters on photocoagulation to maximize safety and efficacy during varicose vein treatment. CW and pulsed modes at 1470 nm were initially compared as a function of power on bovine liver tissue. In the pulsed mode, various parameters including repetition rate, duty cycle, and irradiation time were compared to evaluate tissue response during thermal treatment. The results demonstrated that CW and pulsed modes yielded almost similar coagulation development possibly due to shorter irradiation time of 5 sec. Regardless of laser mode, both repetition rate and duty cycle presented constant coagulation rate whereas longer irradiation time facilitated coagulation process.

PLD를 이용한 ZnO 박막의 후열처리에 관한 연구 (Effects of Post-Annealing Treatment of ZnO Thin Films by Pulsed Laser)

  • 이천;김재홍
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제54권3호
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    • pp.103-108
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    • 2005
  • ZnO thin films on (001) sapphire substrates have been deposited by pulsed laser deposition(PLD) technique using an Nd:YAG laser with a wavelength of 266nm. Before post-annealing treatment in the oxygen ambient, the experiment of the deposition of ZnO thin films has been performed for substrate temperatures in the range of $300\~450^{\circ}C$ and oxygen gas flow rate of $100\~700\;sccm$. In order to investigate the effect of post-annealing treatment of ZnO thin films, films have been annealed at various temperatures after deposition. After post-annealing treatment in the oxygen ambient, the structural properties of ZnO thin films were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and the optical properties of the ZnO were characterized by photoluminescence(PL).

펄스 레이저 증착법으로 성장된 실리콘 박막의 어닐링 온도 변화에 따른 발광 특성연구 (Effect of Annealing Temperature on the Luminescence of Si Nanocrystallites Thin Films Prepared by Pulsed Laser Deposition)

  • 김종훈;전경아;이상렬
    • 한국전기전자재료학회논문지
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    • 제15권1호
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    • pp.75-78
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    • 2002
  • Si thin films on p-type (100) Si substrate have been prepared by a pulsed laser deposition technique using a Nd:YAG laser. The pressure of the environmental gas during deposition was 1 Torr. After deposition, Si thin film has been annealed again at 400-840$^{\circ}C$ in nitrogen ambient. Strong blue photoluminescence (PL) have been observed at room temperature. We report the PL properties of Si thin films with the variation of the annealing temperature.

PLD 기술로 제작된 ZnO 박막의 특성 (Characterization of ZnO Thin Films prepared by Pulsed Laser Deposition Technique)

  • 노임준;신백균;이능헌;김용혁;지승한;이상희;한상옥
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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    • pp.1404-1405
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    • 2006
  • Transparent ZnO thin films were deposited on quartz substrates by a KrF pulsed laser deposition (PLD) technique with different process conditions such as substrate temperature ($T_s$) and oxygen ambient pressure ($pO_2$). Surface morphology, crystal structure, and electrical properties of the ZnO films were investigated in order to characterize their thin film properties. The pulsed laser deposited ZnO films showed highly c-oriented crystalline structures depending on the process conditions: the highest FWHM (Full Width Half Maximum) value of (002) peak was observed for the ZnO film prepared at $T_{s}=550^{\circ}C$, $pO_2$=5mTorr and laser fluence of $2J/cm^2$.

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