The Experts below are selected from a list of 28131 Experts worldwide ranked by ideXlab platform
Dazhi Yang - One of the best experts on this subject based on the ideXlab platform.
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Corrosion resistance of a Laser Spot-welded joint of NiTi wire in simulated human body fluids.
Journal of biomedical materials research. Part A, 2006Co-Authors: Xiao-jun Yan, Dazhi YangAbstract:The purpose of this study was to investigate corrosion resistance of a Laser Spot-welded joint of NiTi alloy wires using potentiodynamic tests in Hank's solution at different PH values and the PH 7.4 NaCl solution for different Cl− concentrations. Scanning electron microscope observations were carried out before and after potentiodynamic tests. The composition of a Laser Spot-welded joint and base metal were characterized by using an electron probe microanalyzer. The results of potentiodynamic tests showed that corrosion resistance of a Laser Spot-welded joint of NiTi alloy wire was better than that of base metal, which exhibited a little higher breakdown potential and passive range, and a little lower passive current density. Corrosion resistances of a Laser Spot-welded joint and base metal decreased with increasing of the Cl− concentration and PH value. The improvement of corrosion resistance of the Laser Spot-welded joint was due to the decrease of the surface defects and the increase of the Ti/Ni ratio. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
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Corrosion resistance of a Laser Spot-welded joint of NiTi wire in simulated human body fluids.
Journal of biomedical materials research. Part A, 2006Co-Authors: Xiao-jun Yan, Dazhi YangAbstract:The purpose of this study was to investigate corrosion resistance of a Laser Spot-welded joint of NiTi alloy wires using potentiodynamic tests in Hank's solution at different PH values and the PH 7.4 NaCl solution for different Cl- concentrations. Scanning electron microscope observations were carried out before and after potentiodynamic tests. The composition of a Laser Spot-welded joint and base metal were characterized by using an electron probe microanalyzer. The results of potentiodynamic tests showed that corrosion resistance of a Laser Spot-welded joint of NiTi alloy wire was better than that of base metal, which exhibited a little higher breakdown potential and passive range, and a little lower passive current density. Corrosion resistances of a Laser Spot-welded joint and base metal decreased with increasing of the Cl- concentration and PH value. The improvement of corrosion resistance of the Laser Spot-welded joint was due to the decrease of the surface defects and the increase of the Ti/Ni ratio.
Xiao-jun Yan - One of the best experts on this subject based on the ideXlab platform.
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Corrosion resistance of a Laser Spot-welded joint of NiTi wire in simulated human body fluids.
Journal of biomedical materials research. Part A, 2006Co-Authors: Xiao-jun Yan, Dazhi YangAbstract:The purpose of this study was to investigate corrosion resistance of a Laser Spot-welded joint of NiTi alloy wires using potentiodynamic tests in Hank's solution at different PH values and the PH 7.4 NaCl solution for different Cl− concentrations. Scanning electron microscope observations were carried out before and after potentiodynamic tests. The composition of a Laser Spot-welded joint and base metal were characterized by using an electron probe microanalyzer. The results of potentiodynamic tests showed that corrosion resistance of a Laser Spot-welded joint of NiTi alloy wire was better than that of base metal, which exhibited a little higher breakdown potential and passive range, and a little lower passive current density. Corrosion resistances of a Laser Spot-welded joint and base metal decreased with increasing of the Cl− concentration and PH value. The improvement of corrosion resistance of the Laser Spot-welded joint was due to the decrease of the surface defects and the increase of the Ti/Ni ratio. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
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Corrosion resistance of a Laser Spot-welded joint of NiTi wire in simulated human body fluids.
Journal of biomedical materials research. Part A, 2006Co-Authors: Xiao-jun Yan, Dazhi YangAbstract:The purpose of this study was to investigate corrosion resistance of a Laser Spot-welded joint of NiTi alloy wires using potentiodynamic tests in Hank's solution at different PH values and the PH 7.4 NaCl solution for different Cl- concentrations. Scanning electron microscope observations were carried out before and after potentiodynamic tests. The composition of a Laser Spot-welded joint and base metal were characterized by using an electron probe microanalyzer. The results of potentiodynamic tests showed that corrosion resistance of a Laser Spot-welded joint of NiTi alloy wire was better than that of base metal, which exhibited a little higher breakdown potential and passive range, and a little lower passive current density. Corrosion resistances of a Laser Spot-welded joint and base metal decreased with increasing of the Cl- concentration and PH value. The improvement of corrosion resistance of the Laser Spot-welded joint was due to the decrease of the surface defects and the increase of the Ti/Ni ratio.
Joseph T. Walsh - One of the best experts on this subject based on the ideXlab platform.
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Laser Spot size and beam profile studies for tissue welding applications
Lasers in Surgery: Advanced Characterization Therapeutics and Systems IX, 1999Co-Authors: Nathaniel M. Fried, V. C. Hung, Joseph T. WalshAbstract:We evaluated the effect of changes in Laser Spot size and beam profile on the thermal denaturation zone produced during Laser skin welding. Our objective was to limit heating of the tissue surface, while creating enough thermal denaturation in the deeper layers of the dermis to produce full-thickness welds. Two-cm-long, full-thickness incisions were made on the backs of guinea pigs, in vivo. India ink was used as an absorber. Continuous-wave, 1.06-μm, Nd:YAG Laser radiation was scanned over the incisions, producing approximately 100 ms pulses. Cooling times of 10.0 s between scans were used. Laser Spot diameters of 1, 2, 4, and 6 mm were studied, with powers of 1, 4, 16, and 36 W, respectively. The irradiance remained constant at 127 W/cm2. 1, 2, and 4 mm diameter Spots produced thermal denaturation to a depth of 570 ± 100 μm, 970 ± 210 μm, and 1470 ± 190 μm, respectively. The 6-mm- diameter Spot produced full-thickness welds (1900 μm), but also burns due to the high incident power. Monte Carlo simulations were also conducted, varying the Laser Spot diameter and beam profile. The simulations verified that an increase in Laser Spot diameter result in an increase in the penetration depth of radiation into the tissue.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Laser tissue welding: Laser Spot size and beam profile studies
IEEE Journal of Selected Topics in Quantum Electronics, 1999Co-Authors: Nathaniel M. Fried, V. C. Hung, Joseph T. WalshAbstract:Evaluates the effect of Laser Spot diameter and beam profile on the shape of the thermal denaturation zone produced during Laser tissue welding, 2-cm-long full thickness incisions were made on the epilated backs of guinea pigs in vivo. India ink was used as an absorber and clamps were used to appose the incision edges. Welding was performed using continuous-wave 1.06-/spl mu/m, Nd:YAG Laser radiation scanned over the incisions to produce /spl sim/100-ms pulses. Laser Spot diameters of 1, 2, 4, and 6 mm were studied, with powers of 1, 4, 16, and 36 W, respectively. The irradiance remained constant at 127 W/cm/sup 2/. Monte Carlo simulations were also conducted to examine the effect of Laser Spot size and beam profile on the distribution of photons absorbed in the tissue. The Laser Spot diameter was varied from 1 to 6 mm, Gaussian, flat-top, dual Gaussian, and dual flat-top beam profiles were studied. The experimental results showed that 1-, 2-, 4-, and 6 mm-diameter Spots produced thermal denaturation to an average depth of 570, 970, 1470, and 1900 /spl mu/m, respectively. Monte Carlo simulations demonstrated that the most uniform distribution of photon absorption is achieved using large diameter dual flat-top beams.
J. Y. Guo - One of the best experts on this subject based on the ideXlab platform.
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Study on fibre Laser Spot welding of TRIP980 steel
Materials Science and Technology, 2014Co-Authors: S. T. Wei, R. D. Liu, L. Lin, J. Y. GuoAbstract:A 980 MPa transformation induced plasticity (TRIP) steel was fibre Laser Spot welded by different Argon (Ar) shielding conditions, Laser power (1000 up to 2500 W) and defocusing distances (−8 up to +8 mm). The surface appearance, cross-section macrostructure, microstructure, hardness, tensile shear properties and fatigue properties of Laser Spot welds were evaluated. The results showed that the welds with Ar shielding had larger weld appearance and bonding sizes, better tensile shear properties compared with the welds without Ar shielding. With the increase in Laser power, the Laser welding mode changed from conduction to keyhole, which improved the bonding size and mechanical properties. The bonding size and mechanical properties increased in the order of defocusing distances of +8, −8, +4, −4 and 0 mm. During the fatigue tests of Laser Spot weld, the fusion zone pullout and sheet transverse fracture failure modes were observed.
Nathaniel M. Fried - One of the best experts on this subject based on the ideXlab platform.
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Laser Spot size and beam profile studies for tissue welding applications
Lasers in Surgery: Advanced Characterization Therapeutics and Systems IX, 1999Co-Authors: Nathaniel M. Fried, V. C. Hung, Joseph T. WalshAbstract:We evaluated the effect of changes in Laser Spot size and beam profile on the thermal denaturation zone produced during Laser skin welding. Our objective was to limit heating of the tissue surface, while creating enough thermal denaturation in the deeper layers of the dermis to produce full-thickness welds. Two-cm-long, full-thickness incisions were made on the backs of guinea pigs, in vivo. India ink was used as an absorber. Continuous-wave, 1.06-μm, Nd:YAG Laser radiation was scanned over the incisions, producing approximately 100 ms pulses. Cooling times of 10.0 s between scans were used. Laser Spot diameters of 1, 2, 4, and 6 mm were studied, with powers of 1, 4, 16, and 36 W, respectively. The irradiance remained constant at 127 W/cm2. 1, 2, and 4 mm diameter Spots produced thermal denaturation to a depth of 570 ± 100 μm, 970 ± 210 μm, and 1470 ± 190 μm, respectively. The 6-mm- diameter Spot produced full-thickness welds (1900 μm), but also burns due to the high incident power. Monte Carlo simulations were also conducted, varying the Laser Spot diameter and beam profile. The simulations verified that an increase in Laser Spot diameter result in an increase in the penetration depth of radiation into the tissue.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Laser tissue welding: Laser Spot size and beam profile studies
IEEE Journal of Selected Topics in Quantum Electronics, 1999Co-Authors: Nathaniel M. Fried, V. C. Hung, Joseph T. WalshAbstract:Evaluates the effect of Laser Spot diameter and beam profile on the shape of the thermal denaturation zone produced during Laser tissue welding, 2-cm-long full thickness incisions were made on the epilated backs of guinea pigs in vivo. India ink was used as an absorber and clamps were used to appose the incision edges. Welding was performed using continuous-wave 1.06-/spl mu/m, Nd:YAG Laser radiation scanned over the incisions to produce /spl sim/100-ms pulses. Laser Spot diameters of 1, 2, 4, and 6 mm were studied, with powers of 1, 4, 16, and 36 W, respectively. The irradiance remained constant at 127 W/cm/sup 2/. Monte Carlo simulations were also conducted to examine the effect of Laser Spot size and beam profile on the distribution of photons absorbed in the tissue. The Laser Spot diameter was varied from 1 to 6 mm, Gaussian, flat-top, dual Gaussian, and dual flat-top beam profiles were studied. The experimental results showed that 1-, 2-, 4-, and 6 mm-diameter Spots produced thermal denaturation to an average depth of 570, 970, 1470, and 1900 /spl mu/m, respectively. Monte Carlo simulations demonstrated that the most uniform distribution of photon absorption is achieved using large diameter dual flat-top beams.
