• Title/Summary/Keyword: multiple laser

Search Result 352, Processing Time 0.023 seconds

Flow Field Analysis around Multi-Cylinders Using Particle Image Velocimetry (PIV를 이용한 다수원주 주위 유동장 해석)

  • 전완수;박준수;권순홍;하동대;최장운;이만형
    • Journal of Ocean Engineering and Technology
    • /
    • v.10 no.3
    • /
    • pp.89-95
    • /
    • 1996
  • The flow field around four cylinders for various angles was investigated utilizing particle image velocimetry(PIV) technique. Flow field was recorded by video camera first. Then application of PIV technique was done to the flow field. The results turned out to be useful to analyze complex flow field around multiple cylinders.

  • PDF

Fabrication of Microstrip Band-Pass Filter using HTS Thin Film (고온초전도 박막을 이용한 마이크로스트립 대역통과 필터의 제작)

  • 허원일;정동철;김민기;임성훈;한병성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 1996.11a
    • /
    • pp.389-392
    • /
    • 1996
  • The recent development of high temperature superconducting epitaxial thin film offer great potential for planar passive microwave application such as ring resonator, filters, transmission lines, and antennas. This paper describes the fundamental properties of Microstrip Band-Pass Filter using HTS Thin Film and its application to microwave devices. In order to fabricate HTS microstrip multiple filters, We have grown laser ablated HTS thin films, patterned by photolithographic process and wet etching processes intro HTS microwave devices.

  • PDF

Bandgap Tuning in InGaAs/InGaAsP Laser Structure by Quantum Well Intermixing

  • Nah Jongbum;Kam PatrickLi
    • Korean Journal of Optics and Photonics
    • /
    • v.16 no.2
    • /
    • pp.159-161
    • /
    • 2005
  • We report the selective area bandgap tuning of multiple quantum well structures by an impurity free vacancy induced quantum well intermixing technique. A 3dB waveguide directional coupler was fabricated in the disordered section of an intermixed quantum well sample as a demonstration of photonic device applications.

A multistage wavelength division multiplexed passive optical network (다단 분기 파장분할 다중방식 수동형 광가입자망)

  • Park, Kun-Youl;Park, Jae-Hyoung;Kim, Geun-Young;Kim, Jin-Hee
    • 한국정보통신설비학회:학술대회논문집
    • /
    • 2008.08a
    • /
    • pp.112-115
    • /
    • 2008
  • The multistage wavelength division multiplexed passive optical network (WDM-PON) with multiple remote nodes (RN) can accommodate widely spread subscribers efficiently and it increases the channel usage. We implemented a multistage RN using band add-drop filters and it was applied to a wavelength-locked Fabry-Petor laser diode based gigabit WDM-PON.

  • PDF

Analyses of Characteristics for Direct Intensity Modulation Scheme

  • Kim, Jung-Tae
    • Journal of information and communication convergence engineering
    • /
    • v.4 no.3
    • /
    • pp.101-104
    • /
    • 2006
  • We have investigated the spectral characteristics of the semiconductor lasers locked to the sidebands of the master laser in this paper, which were expressed by a series of the Bessel function. The numerical model for the semiconductor lasers based on the typical Lang's equation has been extended in order to take into account the simultaneous injection of the multiple sidebands of the directly modulated ML. We analyses characteristics of direct intensity modulation.

Proposed Mechanisms of Photobiomodulation (PBM) Mediated via the Stimulation of Mitochondrial Activity in Peripheral Nerve Injuries

  • Choi, Ji Eun
    • Medical Lasers
    • /
    • v.10 no.4
    • /
    • pp.195-200
    • /
    • 2021
  • Evidence shows that nerve injury triggers mitochondrial dysfunction during axonal degeneration. Mitochondria play a pivotal role in axonal regeneration. Therefore, normalizing mitochondrial energy metabolism may represent an elective therapeutic strategy contributing to nerve recovery after damage. Photobiomodulation (PBM) induces a photobiological effect by stimulating mitochondrial activity. An increasing body of evidence demonstrates that PBM improves ATP generation and modulates many of the secondary mediators [reactive oxygen species (ROS), nitric oxide (NO), cyclic adenosine monophosphate (cAMP), and calcium ions (Ca2+)], which in turn activate multiple pathways involved in axonal regeneration.

10 GHz Multiuser Optical CDMA Based on Spectral Phase Coding of Short Pulses

  • Ruan, Wan-Yong;Won, In-Jae;Park, Jae-Hyun;Seo, Dong-Sun
    • Journal of IKEEE
    • /
    • v.13 no.1
    • /
    • pp.65-70
    • /
    • 2009
  • We propose an ultrashort pulse optical code-division multiple-access (O-CDMA) scheme based on a pseudorandom binary M-sequence spectral phase encoding and decoding of coherent mode-locked laser pulses and perform a numerical simulation to analyze its feasibility. We demonstrate the ability to properly decode any of the multiple (eight) 10 Gbit/s users by the matched code selection of the spectral phase decoder. The peak power signal to noise ratio of properly and improperly decoded $8{\times}10 Gb/s$ signals could be greater than 15 for 127 M-sequence coding.

  • PDF

The Effects of Multiple Recycling on Deinkability, Optical and Physical Properties of Recycled Paper

  • Shin, Jun-Seop;Min, Choon-Ki
    • Journal of Korea Technical Association of The Pulp and Paper Industry
    • /
    • v.31 no.5
    • /
    • pp.18-23
    • /
    • 1999
  • This study examined the effects of multiple recycling on deinkability and properties of recycled paper from laser computer printout(LCPO). First, alkaline paper with a 20% printed area was disintegrated by TAPPI standard disintegrator. After dewatering , the pulp was followed by flotation, handsheet making, and drying at room temperature, in order. A sequence of printing , disintegrating, flotating , handsheet making and drying was one recycling cycle and this cyclic treatment was repeateed from zero to five times. The residual ink content in recycled handsheets by SEM-EDXA and Py-GC analyseswas increased slightly as recycling number increase. After five cycles of recycling the ISO brightness of recycled handsheets dropped to about 90% of the original brightness. However, it had a gain of 10% in opacity. The most of physical properties of recycled handsheets were decreased as recycling numbers increase except of for tear strength.

  • PDF

The Back-bead Prediction Comparison of Gas Metal Arc Welding (아크 용접의 이면비드 예측 비교)

  • Lee, Jeong-Ick;Koh, Byung-Kab
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.16 no.3
    • /
    • pp.81-87
    • /
    • 2007
  • It is important to investigate the relationship between weld process parameters and weld bead geometry for adaptive arc robot welding. However, it is difficult to predict an exact back-bead owing to gap in process of butt welding. In this paper, the quantitative prediction system to specify the relationship external weld conditions and weld bead geometry was developed to get suitable back-bead in butt welding which is widely applied on industrial field. Multiple regression analysis and artificial neural network were used as the research methods. And, the results of two prediction methods were compared and analyzed.