• Title/Summary/Keyword: low intensity laser

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Laser irradiation effect of electrophoretically-coated low-voltage phosphor for the application of Field Emission Display

  • 서도석;송병권;김채옥;남창우;홍진표
    • Proceedings of the Korean Vacuum Society Conference
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    • 2000.02a
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    • pp.152-152
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    • 2000
  • 차세대 평판 디스플레이로 주목박고 있는 FED는 현재 저전압 환경에서 기존의 CRT와 비슷한 해상도와 밝기를 얻지 못하고 있다. 이는 형광체 입자의 표면에 존재하는 결함, 오염, band - bonding과 같은 비발광층과 제조공정 중에 산화되거나 공기중에 노출되어 막 표면이 쉽게 오염되기 때문이다. 따라서 본 연구에서는 전기영동법으로 제작된 형광체의 효율 향상을 위해 레이저 표면 처리효과를 연구하였다. 실험에 사용한 레이저 표면처리 방법은 Nd:YAG pulse(355nm), continuous laser를 이용하였으며 레이저 power와 처리 시간을 변화시키면서 실시하였다. 형광체 막의 표면 두께 측정을 위해 Scanning Electron Microscopy(SEM), 처리된 막의 발광세기를 비교 분석하기 위해 Photoluminescence(PL), Cathodoluminescence(CL) intensity를 측정하였다.

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Development of Micro-opto-mechanical Accelerometer using Optical fiber (광섬유를 이용한 미세 광 기계식 가속도 센서의 개발)

  • Lee, Seung-Jae
    • Journal of the Korean Society of Mechanical Technology
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    • v.13 no.4
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    • pp.93-99
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    • 2011
  • This paper presents a new type of optical silicon accelerometer using deep reactive ion etching (DRIE) and micro-stereolithography technology. Optical silicon accelerometer is based on a mass suspended by four vertical beams. A vertical shutter at the end of the mass can only moves along the sensing axis in the optical path between two single-mode optical fibers. The shutter modulates intensity of light from a laser diode reaching a photo detector. With the DRIE technique for (100) silicon, it is possible to etch a vertical shutter and beam. This ensures low sensitivity to accelerations that are not along the sensing axis. The microstructure for sensor packaging and optical fiber fixing was fabricated using micro stereolithography technology. Designed sensors are two types and each resonant frequency is about 15 kHz and 5 kHz.

The Effects of Low-Intensity Ultrasound and Laser on Healing of Bone Fracture (저강도 레이저와 초음파의 동시 적용이 골절 치유 촉진에 미치는 효과)

  • Lee, Hyun-Kee
    • The Journal of Korean Physical Therapy
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    • v.15 no.4
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    • pp.331-372
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    • 2003
  • The purpose of study was to evaluate effects of low-intensity ultrasound and laser on healing of bone fracture. Twenty fracture patient were selected for this study(fourteen males, six females. mean aged 44.8) fracture area was humerus, tibia, forearm bones. The obtain result are as follows. 1. The result of this study were following that pain score was significantly reduced pre intervention compared with post intervention in male(P<.001). 2. The result of this study were following that pain score was significantly reduced pre intervention compared with post intervention in female(P<.001). 1. The result of this study were following that pain score was not appeared reduced pre intervention compared with post intervention in male and female(P<.001). 4. The result of this study were following that pain score was not appeared pre intervention compared with post intervention in male between age(P<.001). 5. The result of this study were following that pain score was not appeared pre intervention compared with post intervention in female between age (P<.001). 6. The result of this study were following that radiologic score was significantly reduced pre intervention compared with post intervention in male(P<.001). 7. The result of this study were following that radiologic score was significantly reduced pre intervention compared with post intervention in female(P<.001). 8. The result of this study were following that radiologic score was not appeared reduced pre intervention compared with post intervention in male and female(P<.001). 9. The result of this study were following that radiologic score was not appeared pre intervention compared with post intervention in male between ages(P<.001). 10. The result of this study were following that radiologic score was not appeared pre intervention compared with post intervention in female between ages(P<.001). 11. The result of this study were following that healing on fracture area was observed that reduced pre intervention compared with post intervention

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Fatigue Crack Propagation Behavior of Steel Plate of Laser Welded Tailored Blank (테일러드 블랭크 레이저 용접 강판의 피로균열 전파 거동)

  • Han, Moon-Sik;Lee, Yang-Sub
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.3
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    • pp.120-126
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    • 2006
  • In this paper, we investigated the characteristics of fatigue fracture on TB(Tailored Blank) weldment by comparing the fatigue crack propagation characteristics of base metal with those of TB welded sheet used for vehicle body panels. We also investigated the influence of center crack on the fatigue characteristic of laser weld sheet of same thickness. We conducted an experiment on fatigue crack propagation on the base metal specimen of 1.2mm thickness of cold-rolled metal sheet(SPCSD) and 2.0mm thickness of hot-rolled metal sheet(SAPH440) and 1.2+2.0mm TB specimen. We also made an experiment on fatigue crack propagation on 2.0+2.0mm and 1.2+1.2mm thickness TB specimen which had center crack. The characteristics of fatigue crack growth on the base metal were different from those on 1.2+2.0mm thickness TB specimen. The fatigue crack growth rate of the TB welded specimens is slower in low stress intensity factor range$({\Delta}K)$ region and faster in high ${\Delta}K$ region than that of the base metal specimens.

Laser Diagnostics of Spray and Combustion Characteristics Using Multi-Component Mixed Fuels in a D.I. Diesel Engine (다성분 혼합연료를 이용한 디젤 분무 및 연소특성의 광계측 진단)

  • Yoon, Jun-Kyu;Myong, Kwang-Jae;Senda, Jiro;Fujimoto, Hajime;Cha, Kyung-Ok
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.5
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    • pp.172-180
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    • 2006
  • This study was to analyze the effect of mixed fuel composition and mass fraction on the characteristics of evaporating diesel spray and combustion under the various ambient conditions. The characteristics of vaporization distribution and combustion were visualized by laser induced fluorescent method and direct photography. The experiments were conducted in the constant volume vessel and rapid compression expansion machine with optical access. Multi-component fuels mixed i-octane, n-dodecane and n-hexadecane were injected the vessel and rapid compression expansion machine with electronically controlled common rail injector. Experimental results show that fuel vapor formed stratified distribution. And vaporization and diffusion are become actively increasing in mass fraction of low boiling point component. Consequently multi-component fuels were expected to control the evaporating behavior according to their suitable mass fraction.

An immunohistochemical study on the effects of low-level laser irradiation on expression of actin filaments of human gingival fibroblasts in vitro (저출력레이저조사가 배양치은섬유아 세포의 actin filaments발현에 미치는 영향에 관한 면역조직화학적 연구)

  • Kim, Hyung-Sung;Kim, Chun-Suk;Kim, Hyung-Soo;Kim, Hyun-Seop;Kim, Byung-Ock;Han, Kyung-Yoon
    • Journal of Periodontal and Implant Science
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    • v.26 no.4
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    • pp.1003-1012
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    • 1996
  • The induction of a phenotype with preoperties may have clinical significance in the acceleration of the wound-healing process. Wound contraction involves a specialized cell known as the myofibroblast. The myofibroblasts can be identified by their intense staining of actin bundles with anti-actin antibody. Tissue-specific actin distribution is correlated with the contractile activity of the myofibroblasts and smooth muscle etc. This study was performed to determine the expression of actin filaments in the cytoplasm of cultured human gingival fibroblsts after GaAs laser(BIOSAER, Korea) irradiation. Human gingival fibroblasts were cultured from explants of normal interdental gingival tissue. The third-generation fibroblasts were used for immunohistochemical study. The cultured fibroblasts were exposed $0.53joule/cm^2$(lmW, 7 mimutes) of energy density, and then observed by immunohistochemical method using, rabbit anti0gelsolin, hen smooth muscle polyclonal antibody(Chemicon international inc.), and biotinylated goat anti-rabbit IgG(Vectastain) 24-, 36-, 48-hour after laser irradiation Following results were obtained ; 1. In nonirradiated cultures, round shaped active fibroblasts with abundant cytoplasm and prominet nucleoli were observed. 2. In 24- and 36-hour cultures after laser irradiation, spindle shaped cells with long process were observed. The intensity of stain was seen in cytoplasm of these modified fibroblasts. 3. In 48-hoour cultures after laser irradiation, stained spindle shape cell were not observed. The results suggest that the effect of the galium-arsenide laser treatment on cultured gingival fibroblasts is the rapid development of cytoplasmic actin filaments.

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Intermediate band solar cells with ZnTe:Cr thin films grown on p-Si substrate by pulsed laser deposition

  • Lee, Kyoung Su;Oh, Gyujin;Kim, Eun Kyu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2016.02a
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    • pp.247.1-247.1
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    • 2016
  • Low-cost, high efficiency solar cells are tremendous interests for the realization of a renewable and clean energy source. ZnTe based solar cells have a possibility of high efficiency with formation of an intermediated energy band structure by impurity doping. In this work, ZnO/ZnTe:Cr and ZnO/i-ZnTe structures were fabricated by pulsed laser deposition (PLD) technique. A pulsed (10 Hz) Nd:YAG laser operating at a wavelength of 266 nm was used to produce a plasma plume from an ablated a ZnTe target, whose density of laser energy was 10 J/cm2. The base pressure of the chamber was kept at approximately $4{\times}10-7Torr$. ZnTe:Cr and i-ZnTe thin films with thickness of 210 nm were grown on p-Si substrate, respectively, and then ZnO thin films with thickness of 150 nm were grown on ZnTe:Cr layer under oxygen partial pressure of 3 mTorr. Growth temperature of all the films was set to $250^{\circ}C$. For fabricating ZnO/i-ZnTe and ZnO/ZnTe:Cr solar cells, indium metal and Ti/Au grid patterns were deposited on back and front side of the solar cells by using thermal evaporator, respectively. From the fabricated ZnO/ZnTe:Cr and ZnO/i-ZnTe solar cell, dark currents were measured by using Keithley 2600. Solar cell parameters were obtained under Air Mass 1.5 Global solar simulator with an irradiation intensity of 100 mW/cm2, and then the photoelectric conversion efficiency values of ZnO/ZnTe:Cr and ZnO/i-ZnTe solar cells were measured at 1.5 % and 0.3 %, respectively.

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ZnTe:O/CdS/ZnO intermediate band solar cells grown on ITO/glass substrate by pulsed laser deposition

  • Lee, Kyoung Su;Oh, Gyujin;Kim, Eun Kyu
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.197.2-197.2
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    • 2015
  • Low-cost, high efficiency solar cells are tremendous interests for the realization of a renewable and clean energy source. ZnTe based solar cells have a possibility of high efficiency with formation of an intermediated energy band structure by impurity doping. In this work, the ZnTe:O/CdS/ZnO structure was fabricated by pulsed laser deposition (PLD) technique. A pulsed (10 Hz) Nd:YAG laser operating at a wavelength of 266 nm was used to produce a plasma plume from an ablated a ZnTe target, whose density of laser energy was 4.5 J/cm2. The base pressure of the chamber was kept at a pressure of approximately $4{\times}10-7Torr$. ZnO thin film with thickness of 100 nm was grown on to ITO/glass, and then CdS and ZnTe:O thin film were grown on ZnO thin film. Thickness of CdS and ZnTe:O were 50 nm and 500 nm, respectively. During deposition of ZnTe:O films, O2 gas was introduced from 1 to 20 mTorr. For fabricating ZnTe:O/CdS/ZnO solar cells, Au metal was deposited on the ITO film and ZnTe:O by thermal evaporation method. From the fabricated ZnTe:O/CdS/ZnO solar cell, current-voltage characteristics was measured by using HP 4156-a semiconductor parameter analyzer. Finally, solar cell performance was measured using an Air Mass 1.5 Global (AM 1.5 G) solar simulator with an irradiation intensity of 100 mW cm-2.

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Improvement of AlGaAs/GaAs Quantum Well Laser Diodes by Thermal Annealing (AlGaAs/GaAs 레이저 다이오우드의 열처리에 의한 개선에 관한 연구)

  • Jung, Hyon-Pil;Kenzhou Xie;Wie, Chu-Ryang;Lee, Yun-Hyun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.3
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    • pp.449-455
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    • 1993
  • In order to investigate the improvements of relatively poor characteristics of short wave length AlGaAs/GaAs laser diodes which are useful as a light source for short distance communication systems, the low temperature $(<680^{\circ}C)$ grown AlGaAs/GaAs GRINSCH-QW laser diodes by molecular beam epitaxy have been studied by photoluminescence as a function of rapid thermal annealing (RTA) temperature. It is shown that guantum well photoluminescence intensity increased substantially by a factor of 10 after RAT at $950^{\circ}C$ for 10 sec. This is related to the reduction of non-radiative recombination in the guantum well region. The threshold current of annealed laser diode is reduced by a factor, of 4, confirming the improvement of laser diode quality by rapid thermal annealing.

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Effects of GaAIAs Diode Laser for the Expression of TGF-$\beta$ on Lumbar Spinal Cord after Extensor Digitorum Muscle Crush Injury (GaAlAs 다이오드 레이저 조사가 장지신근 압좌손상 후 요수분절의 TGF-$\beta$ 발현에 미치는 영향)

  • Kim Souk-Boum;Nam Ki-Won;Koo Hyun-mo;Lee Sun-Min;Kim Jin-Sang
    • The Journal of Korean Physical Therapy
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    • v.14 no.4
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    • pp.87-94
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    • 2002
  • Low intensity laser irradiation is potential physical agent that triggers the muscle regeneration by previous study. In muscle regeneration, a number of growth factors also promotes that is triggered in response to muscle damage. The transforming growth factor(TGF)-$\beta$ is involved in the activation of cell proliferation and the inhibition of cell differentiation in muscle regeneration. This is secreted not only autocrine system but also paracrine and endocrine. Therefore, We investigated that effects of Gallium aluminum arsenide(GaAlAs) diode laser for the expression of TGF-$\beta$ on lumbar spinal cord after extensor digitorum muscle crush injury. After laser irradiation, the immunoreactivity of TGF-$\beta$ was increased bilaterally in gray mater of spinal cord. Especially, in 1 day, experimental group was highed than control, and in 3 day, lateral motor nucleus were storong immunoreactivy of TGF-$\beta$. Also, in 1 and 2 day, TGF-$\beta$ was showed in white mater as well as gray mater, but in 3 day, only showed in gray mater. These data may suggests to the establishment of laser irradiation on spinal cord for skeletal muscle injury.

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