• Title/Summary/Keyword: pulsed $CO_2$ laser

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펄스 레이저 증착법(PLD)으로 제조된 $LiCoO_2$ 박막의 특성

  • Park, Hyeong-Seok;Choe, Gyu-Ha;Lee, Won-Jun
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.287-287
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    • 2010
  • 휴대용 기기의 사용이 증가하면서 배터리의 고용량화와 소형화가 요구되고 있다. 특히 내시경 캡슐과 같은 의료용 센서 기기에서는 소형화가 매우 중요하며 인체에 해로운 액체전해질이 들어가지 않는 것이 바람직하다. 최근 무선센서, RFID 태그, 스마트 카드 등을 위하여 고체전해질을 사용하는 박막 마이크로 배터리가 개발되고 있으나, 에너지 저장용량이 작아 응용분야가 제한적이다. Si wafer 위에 형성된 고단차의 3차원 구조 위에 박막 배터리를 형성한다면 표면적 증가에 의해 에너지 저장용량 역시 크게 증가할 것이며, Si 기반의 반도체, 디스플레이, 태양전지 등과 쉽게 집적이 가능할 것이다. 본 연구에서는 펄스 레이저 증착법(Pulsed Laser Deposition)으로 리튬 배터리의 cathode 물질인 $LiCoO_2$를 박막으로 제조하고 그 특성을 연구하였다. 펄스 레이저 증착법은 저온 증착이 가능하고 타겟 물질과 같은 조성의 박막을 증착하는 것이 용이한 장점이 있다. Pt, TiN 등의 기판 위에 $LiCoO_2$ 박막을 증착하고 증착 온도와 산소($O_2$) 분압이 박막의 조성, 미세구조, 결정성, 그리고 전하저장용량에 미치는 영향을 고찰하였다.

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The development of power supply of High-Repetition Pulsed $CO_2$ Laser using SMPS (SMPS 방식의 고반복 펄스형 $CO_2$ 레이저의 전원장치 개발)

  • 이동훈;정현주;김도완;김희제
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.02a
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    • pp.316-317
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    • 2000
  • 펄스형 $CO_2$레이저는 적외선 영역인 10.6 $mu extrm{m}$ 파장의 매우 안정된 고출력 펄스를 방출시킬 수 있으므로 산업용, 군사용, 의료용, 각종 물리.화학의 기초 연구용 등의 광범위한 응용 분야에서 각광을 받고 있다. 특히 금속의 정밀절단, 심용접에서는 수 십 Hz로부터 수 kHz의 펄스 출력이 필요하다. 펄스방식은 Normal Pulse와 Super Pulse로 크게 나눌 수 있다. Normal Pulse의 경우에는 Pulse의 파고치가 연속파의 파고치와 동일하기 때문에 펄스시의 평균 출력은 연속파의 경우보다 낮다. Super Pulse의 경우에는 Pulse 파고치를 연속파의 파고치보다 훨씬 높게 할 수 있으므로 평균 출력은 낮지만 첨두 출력이 높아서 유리 등 세라믹 재료의 가공에 널리 사용된다$^{(1)}$ (중략)

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Effects of Low Incident Energy Levels of Infrared Laser Irradiation on the Proliferation of Candida Albicans Part I : A Long Term Study according to Pulse Type

  • Sam-Kun Kim;Phil-Yeon Lee;Ki-Suk Kim
    • Journal of Oral Medicine and Pain
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    • v.19 no.1
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    • pp.9-15
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    • 1994
  • This experiment was performed to confirm the hypothesis that LLLT had biostimulation effect for all kinds of cells and there would be differences in the growth of cells among different types of pulsed laser. 360 samples were used in this study. The samples were randomly divided in 6 groups according to the pulse type : quasi continuous type (CW), pulse 1(P1), pulse 7(P7), pulse 9(P9), pulse 15(P15) and shame-irradiated control(Co) groups. Energy fluences of all experimental groups, P1, P7, P9, P15 and CW were 2.12, 2.12, 6.37, 57.32 and 31.85 mj/cm2 respectively. All samples were irradiated for every 1 minute at 0, 12, 24, 36, 48 and 60 hours. Ten samples of each group were sacrificed at 0 and every 12 hours and then the optical density of all samples was measured with the spectrophotometer. As a result, some types of pulses showed significant differences among groups. The increase of cells were markedly stimulated with laser irradiation in P7 and P9 groups, while inhibited in CW, P1, and P15 groups compared with control group. It is therefore, suggested that specific laser pulse should be recommanded to have the biostimulation effects on the specific tissue or cells, although the biostimulation effect is does dependant.

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GROWTH AND ELECTRICAL PROPERTIES OF (La,Sr)CoO$_3$/Pb(Zr,Ti)O$_3$/(La,Sr)CoO$_3$ HETEROSTRUCTURES FOR FIELD EFFECT TRANSISTOR

  • Lee, J.;Kim, S.W.
    • Journal of the Korean institute of surface engineering
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    • v.29 no.6
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    • pp.839-846
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    • 1996
  • Epitaxial (La, Sr)$CoO_3/Pb(Zr,\;Ti)O_3/(La,\;Sr)CoO_3$by pulsed laser deposition for ferroelectric field effect transistor. Epitaxial $LaCoO_3/Pb(Zr,\;Ti)O_3/(La,\;Sr)CoO_3$ heterostructures exhibited 70$\mu C/cm^2$ and 17 $\mu C/cm^2$at a positively and negatively poled states, respectively. On the other hand, epitaxial (La, Sr)$CoO_3/Pb(Zr,\;Ti)O_3/LaCoO_3$heterostructures show the remnant polarization states opposite to the $LaCoO_3/Pb(Zr,\;Ti)O_3/(La,\;Sr)CoO_3$ heterostructures. This indicates that the interface between (La, Sr)$CoO_3$ (LSCO) and $Pb(Zr, Ti)O_3(PZT)$ layers affects the asymmetric polarization remanence through electrochemical nature. The resistivity of $LaCoO_3$ (LCO) layer was found to be dependent on an ambient oxygen, primarily the ambient oxygen pressure during deposition. The resistivity of the LCO layer varied in the range of 0.1-100 $\Omega$cm. It is suggested that, with an appropriate resistivity of the LCO layer, the LCO/PZT/LSCO heterostructure can be used as the ferroelectric field effect transistor.

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펄스레이져 증착법을 이용한 자기커패시터용 Pt/CoNiFe/$BaTiO_3$/CoNiFe 박막 제조 및 전.자기 특성 연구

  • Na, Yeo-Jin;Yun, Seong-Uk;Kim, Cheol-Seong;Sim, In-Bo
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.240.1-240.1
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    • 2011
  • 본 연구에서는 펄스레이져 박막 증착법(Pulsed Laser Deposition;PLD)을 이용하여 연자성의 CoNiFe (CNF) 물질과 강유전 특성의$BaTiO_3$ (BTO) 물질을 다층박막 구조로 제작하여 약자장(H=200 Oe)에 의해 에너지를 집적 시키거나 유전상수를 조절하여 박막의 구조 변화에 따른 커패시턴스 변화를 연구하였다. 다양한 구조의 다층 박막은 Si/$SiO_2$/Ti/Pt(111) 기판상에 PLD을 이용하여 증착하였으며, Phillp's X-선 회절기 (XRD)를 이용하여 결정구조와 격자 상수를 결정하였다. FE-SEM, TEM, AFM 및 EDS를 이용하여 박막 표면/단면의 미세구조 및 물질에 따른 조성비를 확인하였다. 자기적 특성을 위해Vibrating Sample Magnetometer (VSM)를 측정하였고, 전기적 특성은 LCR meter를 이용하여 측정하였다.

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Progress in the co-evaporation technologies developed for high performance REBa2Cu3O7-δ films and coated conductors

  • Lee, J.W.;Yoo, S.I.
    • Progress in Superconductivity and Cryogenics
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    • v.14 no.4
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    • pp.5-11
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    • 2012
  • In this review article, we focus on various co-evaporation technologies developed for the fabrication of high performance $REBa_2Cu_3O_{7-{\delta}}$ (RE: Y and Rare earth elements, REBCO) superconducting films. Compared with other manufacturing technologies for REBCO films such as sputtering, pulsed laser deposition (PLD), metal-organic deposition (MOD), and metal organic chemical vapor deposition (MOCVD), the co-evaporation method has a strong advantage of higher deposition rate because metal sources can be used as precursor materials. After the first attempt to produce REBCO films by the co-evaporation method in 1987, various co-evaporation technologies for high performance REBCO films have been developed during last several decades. The key points of each co-evaporation technology are reviewed in this article, which enables us to have a good insight into a new high throughput process, called as a Reactive Co-Evaporation by Deposition and Reaction (RCE-DR).

Effect of Tin Codoping on Transport and Magnetic Properties of Chromium-doped Indium Oxide Films

  • Kim, Hyo-Jin;Kim, Hyoun-Soo;Kim, Do-Jin;Ihm, Young-Eon;Choo, Woong-Kil;Hwang, Chan-Yong
    • Journal of Magnetics
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    • v.13 no.3
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    • pp.88-91
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    • 2008
  • This study examined the effect of Sn co-doping on the transport and magnetic properties of Cr-doped $In_2O_3$ thin films grown on (100) silicon substrates by pulsed laser deposition. The experimental results showed that Sn co-doping enhances the magnetization and appearance of the anomalous Hall effect, and increases the carrier (electron) concentration. These results suggest that the conduction carrier plays an important role in enhancing the ferromagnetism of a laser-deposited Cr-doped $In_2O_3$ film, which may have applications in transparent oxide semiconductor spin electronics devices.

CO Gas Sensing Characteristic of ZnO Thin Film/Nanowire Based on p-type 4H-SiC Substrate at 300℃ (P형 4H-SiC 기판에 형성된 ZnO 박막/나노선 가스 센서의 300℃에서 CO 가스 감지 특성)

  • Kim, Ik-Ju;Oh, Byung-Hoon;Lee, Jung-Ho;Koo, Sang-Mo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.2
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    • pp.91-95
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    • 2012
  • ZnO thin films were deposited on p-type 4H-SiC substrate by pulsed laser deposition. ZnO nanowires were formed on p-type 4H-SiC substrate by furnace. Ti/Au electrodes were deposited on ZnO thin film/SiC and ZnO nanowire/SiC structures, respectively. Structural and crystallographical properties of the fabricated ZnO thin film/SiC and ZnO nanowire/SiC structures were investigated by field emission scanning electron microscope and X-ray diffraction. In this work, resistance and sensitivity of ZnO thin film/SiC gas sensor and ZnO nanowire/SiC gas sensor were measured at $300^{\circ}C$ with various CO gas concentrations (0%, 90%, 70%, and 50%). Resistance of gas sensor decreases at CO gas atmosphere. Sensitivity of ZnO nanowire/SiC gas sensor is twice as big as sensitivity of ZnO thin film/SiC gas sensor.

Application of the Laser Vision Sensor for Corrugated Type Workpiece

  • Lee, Ji-Hyoung;Kim, Jae-Gwon;Kim, Jeom-Gu;Park, In-Wan;Kim, Hyung-Shik
    • 제어로봇시스템학회:학술대회논문집
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    • 2004.08a
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    • pp.499-503
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    • 2004
  • This application-oriented paper describes an automated welding carriage system to weld a thin corrugated workpiece with welding seam tracking function. Hyundai Heavy Industries Corporation has developed an automatic welding carriage system, which utilizes pulsed plasma arc welding process for corrugated sheets. It can obtain high speed welding more than 2 times faster than traditional TIG based welding system. The aim of this development is to increase the productivity by using automatic plasma welding carriage systems, to track weld seam line using vision sensor automatically, and finally to provide a convenience to operator in order to carry out welding. In this paper a robust image processing and a distance based tracking algorithms are introduced for corrugated workpiece welding. The automatic welding carriage system is controlled by the programmable logic controller(PLC), and the automatic welding seam tracking system is controlled by the industrial personal computer(IPC) equipped with embedded OS. The system was tested at actual workpiece to show the feasibility and performance of proposed algorithm and to confirm the reliability of developed controller.

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