• Title/Summary/Keyword: Soft Laser

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Laser Resurfacing after Facial Free Flap Reconstruction

  • Kim, Beom-Jun;Lee, Yun-Whan;You, Hi-Jin;Hwang, Na-Hyun;Kim, Deok-Woo
    • Medical Lasers
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    • v.8 no.1
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    • pp.7-12
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    • 2019
  • Background and Objectives Skin and soft tissue defects can be treated according to a range of strategies, such as local flap, skin graft, biological dressing, or free flap. On the other hand, free tissue transfer usually leaves a distinct scar with an inconsistency of color or hypertrophy. This problem is highlighted if the defect is located on the face, which could have devastating effects on a patient's psychosocial health. Materials and Methods The authors used an erbium : yttrium-aluminum-garnet (Er:YAG) laser to resurface the free flap skin and match the color with the surrounding facial skin. This study evaluated the effectiveness of laser skin resurfacing on the harmonious color matching of transferred flap. Patients who had undergone laser resurfacing on facial flap skin between January 2014 and December 2018 were reviewed retrospectively. An ablative 2,940-nm fractional Er:YAG laser treatment was delivered to the entire flap skin at 21 J/cm2 with the treatment end-point of pinpoint bleeding. Several months later, the clinical photographs were analyzed. The L*a*b* color co-ordinates of both the flap and surrounding normal skin were measured using Adobe Photoshop. The L*a*b* color difference (ΔE) for the scar and normal surrounding skin were calculated using the following equation: ${\Delta}E=\sqrt{({\Delta}L)^2+({\Delta}a)^2+({\Delta}b)^2}$ Results All five patients were satisfied with the more natural appearance of the flaps. The ΔE values decreased significantly from the pre-treatment mean value of 19.64 to the post-treatment mean value of 11.39 (Wilcoxon signed-rank test, p = 0.043). Conclusion Ablative laser resurfacing can improve the aesthetic outcome of free tissue transfer on the face.

Development of a soft X-ray microscopy system for Biological Application (생물의료용 연 X-선 현미경 시스템 개발)

  • Kim, Gyeong-U;Gwon, Yeong-Man;Kim, Gyu-Gyeom;Min, Jong-Hwan;Park, Jeong-Gwon;Im, Jong-Hyeok;Nam, Gi-Yong;Yun, Gwon-Ha;Min, Jin-Yeong
    • Proceedings of the Optical Society of Korea Conference
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    • 2005.02a
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    • pp.264-265
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    • 2005
  • In this paper the conceptual design and development of a compact vertical type soft x-ray microscope is described. This x-ray microscope operates in the water window wavelength region(2.3 ${\sim}$ 4.4nm), where natural contrast between carbon(protein) and oxygen(water) allows imaging of unstained biological material their natural, hydrated environment. Until now, operational x-ray microscopes are based on synchrotron radiation sources, which limit their accessibility. Many biologists would benefit from having the x-ray microscope as a tool among other tools in their own laboratory, For this purpose we introduced the compact vertical type soft X-ray microscope with 50 nm resolution for biomedical application. The compact vertical type soft x-ray microscope is based on a laser plasma x-ray source, doubled ellipsoidal condenser reflective optics, diffractive zone plate optics and MCP coupled with CCD to record an x-ray image.

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Special quality research about action output waveform change by gap (1.0mm and 1.6mm) difference of $CO_2$ laser for skin disease (피부질환을 위한 $CO_2$ 레이저의 공극 (1.0mm 및 1.6mm)차이에 따른 동작출력 파형변화에 관한 특성연구)

  • Kim, Whi-Young
    • Proceedings of the KIEE Conference
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    • 2007.04c
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    • pp.156-158
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    • 2007
  • Laser wave length can have evaporation effect by absorption because outer skin or tissue of focus is consisted of water almost though absorption of water occurs more than 90% almost in formation thickness of very thin floor Can operate outer skin, steam by floor and correct incision of formation is available. Suture surgical operation is avaliable to vein or lymph system and surgical operation region can dry and see as eye and radish bleeding surgical operation is avaliable Specially, stability of tube both end output about pulse by weight very, this research can cause various curative effect because can reduce bulk and control easily current wave style of medical laser using electric power conversion device of high frequency way. If introduce ZVS (Zero Voltage Switching) or ZVZCS (Zero Voltage and Zero Current Switching), is more profitable because can reduce switching damage Because electric power department of proposed medical laser can do stable soft-switching in wide subordinate extent introducing ZVZCS technique by the first help and control department composes microcontroller, output current waveform user have free form make. Result that experiment because design and manufacture, brought result that improve of 20% than existing equipment, and will be bought to get into superior result if supplement as systematic late.

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X-ray laser development using laser-produced plasmas (레이저-플라즈마를 이용한 X-선 레이저의 연구)

  • 남창희
    • Korean Journal of Optics and Photonics
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    • v.3 no.1
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    • pp.67-72
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    • 1992
  • Since the inception of the idea to develop an X-ray laser in 1960's, a rapid progress to demonstrate soft X-ray lasers in the wavelength region below 300$\AA$ has been made during the last ten years. Among many prospective proposals, the recombination scheme and the collisional exitation scheme have been most successful in achieving a significant gain. An appreciable single-pass amplification was achieved at 182 $\AA$ from CVI ions using the recombination scheme and at 206 and 290$\AA$ from the Se XXV ions using the collisional excitation scheme. The current research on X-ray lasers emphasizes the enhancement of amplification upto saturation and the extension of operating wavelength to shorter wavelengths, especially to the water window region between 23 and 44 $\AA$. X-ray lasers are expected to open many application fields, such as X-ray laser microscopy, X-ray holography, X-ray lithography, and more, in the near future.

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Pulsed Laser System of Ultra-scan Way for Uterus Rehabilitation Treatment (자궁 재활치료를 위한 울트라-스캔 방식의 펄스형 레이저시스템)

  • Kim, Whi-Young
    • The Journal of the Korea Contents Association
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    • v.9 no.6
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    • pp.256-265
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    • 2009
  • Laser output becomes output adjustment from 20 w to 100 w consecutively and time of exposure is available adjustment through water plant in 0.01 seconds. Pulse action can intercept laser beam periodically and supermarket pulse 0.1 $\sim$ between 1ms discharge consist and momentary laser output is increased to 5 $\sim$ 10. Specially, that must remove malignancy cell in womb nine escarps in the case of uterine cancer first of all stability of tube output about pulse by weight very, stable soft switching action area is defined without high frequency transformer leakage inductance ($L_1$) increase and additional series inductor insertion to converter the first main circuit securing zero voltage and marks of switching action in this research specially, because circulation current path of inductor ($L_f$) current is intercepted, converter the first main circuit switching component and spiritual enlightenment damage of high frequency transformer take decreasing greatly and high frequency the second stoppage department ($D_5,\;D_6$) becomes soft switching, and also, switching damage absorption quantity characteristic that can come to life again as subordinate have, and to become tube stabilization design and result that manufacture and experiment, brought result that improve of 10% than existing equipment, and if supplement as systematic late, it becomes thought to get into superior result.

Efficient Approach to Measure Crystallization Temperature in Amorphous Thin Film by Infrared Reflectivity

  • Wang, Wenxiu;Saito, Shin;Yakabe, Hidetaka;Takahashi, Migaku
    • Journal of Magnetics
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    • v.18 no.2
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    • pp.86-89
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    • 2013
  • This paper shows a new effective approach to measure crystallization temperature of soft magnetic underlayer (SUL) for next generation of heat assisted perpendicular recording media. This approach uses temperature dependent reflectivity, which shows a clear jump when samples are crystallized. To achieve this measurement, an optical system is set up using hot plate and infrared laser. Reflectivity of SUL $(Co_{70}Fe_{30})_{92}Ta_3Zr_5$ shows a clear jump at its amorphous-crystalline transition temperature. Experiment results show this effect is clear in infrared region, and is weak for visible light.

Soft X-ray Nano-spectroscopy for Electronic Structures of Transition Metal Oxide Nano-structures

  • Oshima, Masaharu
    • Applied Science and Convergence Technology
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    • v.23 no.6
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    • pp.317-327
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    • 2014
  • In order to develop nano-devices with much lower power consumption for beyond-CMOS applications, the fundamental understanding and precise control of the electronic properties of ultrathin transition metal oxide (TMO) films are strongly required. The metal-insulator transition (MIT) is not only an important issue in solid state physics, but also a useful phenomenon for device applications like switching or memory devices. For potential use in such application, the electronic structures of MIT, observed for TMO nano-structures, have been investigated using a synchrotron radiation angle-resolved photoelectron spectroscopy system combined with a laser molecular beam epitaxy chamber and a scanning photoelectron microscopy system with 70 nm spatial resolution. In this review article, electronic structures revealed by soft X-ray nano-spectroscopy are presented for i) polarity-dependent MIT and thickness-dependent MIT of TMO ultrathin films of $LaAlO_3/SrTiO_3$ and $SrVO_3/SrTiO_3$, respectively, and ii) electric field-induced MIT of TMO nano-structures showing resistance switching behaviors due to interfacial redox reactions and/or filamentary path formation. These electronic structures have been successfully correlated with the electrical properties of nano-structured films and nano-devices.

Highly Efficient Mutually Pumped Phase Conjugators Using BaTiO3:Ce

  • Shin, Seung-Ho;Dou, Shuo-Xing
    • Journal of the Optical Society of Korea
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    • v.8 no.2
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    • pp.79-82
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    • 2004
  • High-efficiency mutually pumped phase conjugation (MPPC) has been realized in a BaTiO$_3$:Ce crystal in the bridge geometry. The laser source is a dye laser operating from 580 to 650 nm. We have observed that, with a beam ratio of 1, self-pumped phase conjugation (SPPC) appears and competes with MPPC at short wavelengths while it disappears at long wavelengths. When the beam ratio is slightly higher than 1, SPPC no longer occurs. Phase conjugate reflectivity near 500% has been obtained at a beam ratio of 70. Our experiments demonstrate that Ce-doped BaTiO$_3$crystals, which have already been found efficient in SPPC experiments, are also efficient for the generation of MPPC.

Sample Preparation for Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

  • Kim, Jeongkwon
    • Mass Spectrometry Letters
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    • v.6 no.2
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    • pp.27-30
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    • 2015
  • This article reviews the fundamentals of sample preparation used in matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). MALDI is a soft ionization method used to generate analyte ions in their intact forms, which are then detected in MS analysis. MALDI-MS boasts fast analysis times and easy-to-use operation. The disadvantages of MALDI-MS include the occurrence of matrix-associated peaks and inhomogeneous distribution of analyte within the matrix. To overcome the disadvantages of MALDI-MS, various efforts have been directed such as using different matrices, novel matrix systems, various additives, and different sample preparation methods. These various efforts will be discussed in detail. This article will benefit those who would like to obtain basic knowledge of MALDI sample preparation and those who would like to use MALDI-MS in their chemical analyses.

Experimental and Computational Studies for Flow Distribution In a Rectangular Duct System with Two Branches (두 개의 분지관을 가진 직사각형 덕트 내의 유량배분에 관한 실험 및 수치계산 연구)

  • 윤영환;배택희;박원구
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.9
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    • pp.766-773
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    • 2002
  • Flow distributions in a rectangular duct with two branch ducts are measured by 5 W laser doppler velocity meter. The fluid flows are also computed by commercial soft-ware of STAR-CD for comparison between them. The Reynolds numbers in the main duct are from 4,226 to 17,491. The ratios distributed into two branches from the main duct are in-variant to Reynolds numbers according to both of numerical and experimental results. However computed velocity profiles at exit of each branch are somewhat different from measured profiles at the same location.