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- 摘要
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- 实验方案
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Development of a new multi-mode NIR laser system for photodynamic therapy
摘要： Photodynamic Therapy (PDT) has been used in various fields especially in cancer treatment. In PDT, designing a light source has vital importance in order to achieve a successful treatment. Among the light sources, Lasers are important candidates for their precise wavelengths to activate the photosensitizers (PS), coherent nature and fiber-coupled usage. In order to achieve perfect PDT treatment, the Laser light sources needs to be embedded with high stability current, temperature controllers and closed loop control systems. In this study, a novel Multi-mode PDT Laser system (MPTL) was developed with four different radiation modes. Importantly, Super Pulse Mode (SPM) was implemented for the first time among the PDT Laser systems in the open literature to minimize the thermal damage to the target tissue. The proposed system achieved high optical output stability by precise current and temperature control of the Laser resonator. The MPTL achieved high optical output stability ( ± 1mW) in the range of 0–1500 mW, high wavelength stability ( ± 1nm) at 635 nm, and high temperature stability ( ± 0.2 °C) in all radiation modes. The MPTL system with super pulse mode can be safely used for wide range of PDT clinical applications.
关键词： Pulse mode laser,Photodynamic therapy,PDT light source,NIR,Super-pulse,Laser system,Multi-mode
更新于2025-09-23 15:21:01
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Feasibility of using acoustic method in monitoring the penetration status during the Pulse Mode Laser Welding process
摘要： In this paper, the feasibility of using acoustic method to monitor the depth of penetration was investigated by determine the characteristic of the acquired sound throughout the pulse mode laser welding process. To achieve the aim, the sound signal was acquired during the pulsed laser welding process on the 2 mm structural carbon steel plate. During the experiment, the laser peak power and pulse width was set to be varied while welding speed was constantly at 2 mm/s. Result from the experiment revealed that the sound pressure level of the acquired sound was linearly related to the pulse energy as well as the depth of penetration for welding process using 2ms pulse width. However, as the pulse width increase, the sound pressure level show insignificant change with respect to the change in the depth of penetration when the pulse energy reaches certain values. The reported result shows that this was happen due to the occurrence of spatter which suppressed the information associated with the generation of plasma plume as the product of high pulse energy. In this work, it was demonstrated that in some condition, the acoustic method was found to be potentially suitable to be used as a medium to monitor the depth of weld on online basis. To increase the robustness of this method to be used in wider range of parameter, it was believed that some other post processing method is needed in order to extract the specific information associated with the depth of penetration from the acquired sound.
关键词： depth of penetration,acoustic method,sound pressure level,plasma plume,pulse mode laser welding
更新于2025-09-11 14:15:04