- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fluorinated and Bio-Based Polyamides with High Transparencies and Low Yellowness Index
摘要： Bio-based polyamides with high transparency and low yellowness were synthesized using 4,4'-bis(trifluoroacetamido)-α-truxillic acid (ATA-F1) and 4,4'-bis(pentafluoropropionamido)-α-truxillic acid (ATA-F2) as a fluoroalkylated aromatic dicarboxylic acid, and various aromatic diamines. The introduction of fluorine side chains improved the transparency of the polyamide film, and suppressed its yellowness. On the other hand, water repellency, which should be a general characteristic of the fluorinated polymers, was not observed. By using ATA-F1 and various aromatic diamines, aromatic and fluorinated polyamides were obtained. In addition, these also demonstrated a high transparency and a low yellowness index. The heat resistance properties of all the obtained polyamides was over 250 °C, and the characteristics of the bio-based polyamides from 4-aminocinnamic acid derivatives were retained.
关键词： bio-based polymer,polyamides,transparent materials,fluorinated polymer
更新于2025-09-23 15:22:29
-
One-Step Femtosecond Laser Stealth Dicing of Quartz
摘要： We report on a one-step method for cutting 250-μm-thick quartz plates using highly focused ultrashort laser pulses with a duration of 200 fs and a wavelength of 1030 nm. We show that the repetition rate, the scan speed, the pulse overlap and the pulse energy directly influence the cutting process and quality. Therefore, a suitable choice of these parameters was necessary to get single-pass stealth dicing with neat and flat cut edges. The mechanism behind the stealth dicing process was ascribed to tensile stresses generated by the relaxation of the compressive stresses originated in the laser beam focal volume during irradiation in the bulk material. Such stresses produced micro-fractures whose controlled propagation along the laser beam path led to cutting of the samples.
关键词： ultrashort laser pulses,stealth dicing,transparent materials,heat accumulation,quartz
更新于2025-09-23 15:19:57
-
Parameters Affecting the Welding of Transparent Materials Using Femtosecond Laser Pulses
摘要： There is a pressing need for an accurate process in industrial laser applications such as welding transparent materials. Femtosecond laser pulses, which depend on the nonlinear absorption properties, can be utilized to weld transparent materials. This technique can be applied not only in welding different transparent materials such as glass and polymers, but also in welding opaque materials such as metals, depending on the selection of an appropriate laser wavelength. The parameters that affect the technique such as Keldysh parameter, pulse energy, pulse repetition rate, pulse duration and nonlinear absorptivity were studied. To explain the welding process, an example of an experimental setup and its requirements was described. Besides that, the challenges for the welding process and their voids were also discussed.
关键词： Laser welding,Femtosecond laser,Nonlinear absorption,Transparent materials
更新于2025-09-12 10:27:22
-
High Intensity Laser Induced Reverse Transfer: Solution for Enhancement of Biocompatibility of Transparent Biomaterials
摘要： Bioactive glass is used extensively in biomedical applications due to its quality and effectiveness in tissue regeneration. Bioactive glasses are able to interact with biological systems and can be used in humans to improve tissue regeneration without any side effects. Bioactive glass is a category of glasses that maintain good contact with body organs and remain biocompatible for a long time after implementation. They have the potential to form a hydroxyapatite surface as a biocompatible layer after immersion in body fluid. In this research, glass biocompatibility was modified using a deposition method called the high intensity laser induced reverse transfer (HILIRT) method and they were utilized as enhanced-biocompatibility bioactive glass (EBBG) with a correspondent nanofibrous titanium (NFTi) coating. HILIRT is a simple ultrafast laser method for improving implants for biomedical applications and provides a good thin film of NFTi on the glass substrate that is compatible with human tissue. The proposed method is a non-chemical method in which NFTi samples with different porosities and biocompatibilities are synthesized at various laser parameters such as power and frequency. Physical properties and cell compatibility and adhesion of these NFTi before and after immersion in simulated body fluid (SBF) were compared. The results indicate that increasing laser intensity and frequency leads to more NFTi fabrication on the glass with no toxicity and better cell interaction and adhesion.
关键词： biocompatibility,laser nanofabrication,nano fibrous biomaterials,transparent materials
更新于2025-09-12 10:27:22
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Generation of Vector Bessel Beams and their Application for Laser Microprocessing of Transparent Materials
摘要： Bessel beams are perfect candidates for laser microprocessing of transparent materials due to generation of high aspect ratio micro voids [1], and ability to control micro crack formation enables to efficiently cut them [2, 3]. The crack propagation direction is controlled by inducing asymmetry to beam profile [3], and allows ultra-fast glass cutting over non-straight lines. The laser-matter interaction of various nondiffracting beams is heavily investigated and their utilisation for laser microprocessing is soon to be expected. Vector beams that are more exotic than scalar counterparts and can have additional beneficial properties for micro-manufacturing of materials. For instance, vector Bessel beam has a doughnut shaped intensity profile with complex spatial distribution of polarisation and can be de-composed to two transverse polarisation intensity components [4]. In this work, we examine generation of vector Bessel beams using an axicon and an s-plate (Workshop of photonics) – radial polarization converter [5]. The s-plate allows generation of azimuthally or radially polarized beams while axicon converts it to nondifftracting Bessel vector beam. The polariser was used to separate its orthogonal polarisation components (Fig. 1). The proposed approach to generate these beams is beneficial for high energy beam systems because s-plate withstands ultrashort (fs-ps) high power pulses. To investigate their applicability to transparent material micro-fabrication we performed microprocessing of a glass with vector Bessel beams and were able to induce high aspect ratio volume modifications and micro cracks in transparent materials. Vector Bessel beams produces cylinder shaped material modifications of glass (Fig 2 a)) while the use of single polarisation component generates two parallel needle like material modification (Fig. 2 b)). By elongating the pulse duration to few ps we have observed micro crack formation extending perpendicular to the beam propagation direction and to two intensity peaks. (Fig. 2 c)). The produced modifications are investigated to increase the laser microprocessing quality and speed.
关键词： Bessel beams,laser microprocessing,transparent materials,axicon,vector beams,s-plate
更新于2025-09-12 10:27:22