• Laser Solutions
• /
• v.2 no.1
• /
• pp.43-50
• /
• 1999

For the conventional welding method. the high heat transfer makes the crystallized zone of the work material unavoidable. Whereas the laser is able to weld the amorphous metal without a crystallized zone, because heat transfer is limited within a very small restricted volume. In this paper, the possibilities and the limits of the laser welding were studied to utilize the advantageous properties of amorphous metal foils.

• Proceedings of the Korean Society of Laser Processing Conference
• /
• 2000.06a
• /
• pp.55-60
• /
• 2000

Laser welding is an important technology in the assembly of automotive. In this paper, Nd:YAG laser welding of applications for auto body assembly will be introduced. This paper will describe characteristics of the CW Nd:YAG laser lap-joint welding, and laser welding of specific configurations for a Zinc-coated steel. Experimental results indicated that the weld quality of auto body assembly using the CW Nd:YAG laser welding technology.

• Journal of Periodontal and Implant Science
• /
• v.52 no.1
• /
• pp.77-87
• /
• 2022

Purpose: This pilot study assessed the immediate in vivo effect of high peak pulse power neodymium-doped yttrium aluminum garnet (Nd:YAG) laser monotherapy on selected red/orange complex periodontal pathogens in deep human periodontal pockets. Methods: Twelve adults with severe periodontitis were treated with the Laser-Assisted New Attachment Procedure (LANAP®) surgical protocol, wherein a free-running, digitally pulsed, Nd:YAG dental laser was used as the initial therapeutic step before mechanical root debridement. Using a flexible optical fiber in a handpiece, Nd:YAG laser energy, at a density of 196 J/cm² and a high peak pulse power of 1,333 W/pulse, was directed parallel to untreated tooth root surfaces in sequential coronal-apical passes to clinical periodontal probing depths, for a total applied energy dose of approximately 8-12 joules per millimeter of periodontal probing depth at each periodontal site. Subgingival biofilm specimens were collected from each patient before and immediately after Nd:YAG laser monotherapy from periodontal pockets exhibiting ≥6 mm probing depths and bleeding on probing. Selected red/orange complex periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia/nigrescens, Fusobacterium nucleatum, Parvimonas micra, and Campylobacter species) were quantified in the subgingival samples using established anaerobic culture techniques. Results: All immediate post-treatment subgingival biofilm specimens continued to yield microbial growth after Nd:YAG laser monotherapy. The mean levels of total cultivable red/orange complex periodontal pathogens per patient significantly decreased from 12.0% pretreatment to 4.9% (a 59.2% decrease) immediately after Nd:YAG laser monotherapy, with 3 (25%) patients rendered culture-negative for all evaluated red/orange complex periodontal pathogens. Conclusions: High peak pulse power Nd:YAG laser monotherapy, used as the initial step in the LANAP® surgical protocol on mature subgingival biofilms, immediately induced significant reductions of nearly 60% in the mean total cultivable red/orange complex periodontal pathogen proportions per patient prior to mechanical root instrumentation and the rest of the LANAP® surgical protocol.

• Proceedings of the KWS Conference
• /
• 2000.04a
• /
• pp.139-143
• /
• 2000

Laser beam weldability of Zircaloy-4 was investigated using a pulsed Nd:YAG laser of 550W average power. Mechanical properties and microstructure of laser butt welded Zircaloy-4 test specimens were examined. The influence of laser generated during laser welding was analyzed and optimum laser welding parameters were investigated.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.437-438
• /
• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.06a
• /
• pp.425-426
• /
• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.405-406
• /
• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.391-392
• /
• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2009.10a
• /
• pp.25-26
• /
• 2009

• Proceedings of the Optical Society of Korea Conference
• /
• 1989.02a
• /
• pp.32-35
• /
• 1989

A 150W industrial Nd:YAG laser was developed. The thermal lensing effect was examined and the radius and position of rear mirror were optimized for higher efficiency. The efficiency of 2.5% was achieved. Also, the performance of laser welding in fine thermocouples and between high-temperature-melting dissimilar metals were investigated.