Laboratory for High Performance Ceramics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, 8600 Duebendorf, Switzerland.
Published: January 2019
AI Article Synopsis
Article Abstract
Freestanding SiCNO ceramic pieces with sub-mm features were produced by laser crosslinking of carbosilane and silazane polymer precursors followed by pyrolysis in inert atmosphere. Three different pulsed UV laser systems were investigated, and the influence of laser wavelength, operating power and scanning speed were all found to be important. Different photoinitiators were tested for the two lasers operating at 355 nm, while for the 266 nm laser, crosslinking occurred also without photoinitiator. Pre-treatment of glass substrates with fluorinated silanes was found to ease the release of green bodies during solvent development. Polymer crosslinking was observed with all three of the laser systems, as were bubbles, surface charring and in some cases ablation. By focusing the laser beam several millimeters above the surface of the resin, selective polymer crosslinking was observed exclusively.
Harvard Medical School, Boston, MA 02114, USA; Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Cardiology, Erasmus Medical Center, Rotterdam GD3015, The Netherlands; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
Photoacoustic microscopy (PAM) is a high-resolution and non-invasive imaging modality that provides optical absorption contrast. By employing dual- or multiple-wavelength excitation, PAM extends its capabilities to offer valuable spectroscopic information. To achieve efficient multispectral PAM imaging, an essential requirement is a light source characterized by a high repetition rate and switching rate, a ≈microjoule pulse energy, and a ≈nanosecond pulse duration.
Rate coefficients for the reaction of CH with CHO were measured for the first time over the temperature range of 37-603 K, with the CH radicals produced by pulsed laser photolysis and detected by CH radical chemiluminescence following their reaction with O. The low temperature measurements (≤93 K) relevant to the interstellar medium were made within a Laval nozzle gas expansion, while higher temperature measurements (≥308 K) were made within a temperature controlled reaction cell. The rate coefficients display a negative temperature dependence below 300 K, reaching (1.
Introduction: Aesthetic medicine has evolved towards minimally invasive procedures, with biostimulators like Poly-L-Lactic Acid (PLLA), Calcium Hydroxylapatite (CaHA), and Polycaprolactone (PCL) gaining attention for their role in collagen induction, improving skin texture, elasticity, and volume. Combining these agents with other treatments-such as botulinum toxin, dermal fillers, and energy-based devices (e.g.
We have grown (111)- and (001)-oriented NiO thin films on (0001)-Sapphire and (001)-MgO substrates
using pulsed laser deposition (PLD), respectively. DC magnetic susceptibility measurements underline
that the Néel temperatures of the samples are beyond room-temperature. This is further confirmed by
the presence of two-magnon Raman scattering modes in these films in ambient conditions.
Cascaded Raman fiber lasers (CRFLs) with wavelength-independent feedback can provide power at any wavelength in near-IR regions. However, broad feedback leads to a broad output spectrum, decreasing spectral power density at a desired wavelength. The output characteristics of CRFLs can be controlled by controlling the feedback.
