Polyimide/crown ether composite film with low dielectric constant and low dielectric loss for high signal transmission.

Dielectric properties of polyimide (PI) are constrained by its inherent molecular structure and inter-chain packing capacities. The compromised dielectric properties of PI, however, could be rescued by introducing trifluoromethyl and forming a host-guest inclusion complex with the introduction of crown ethers (CEs). Herein, we report PI/crown ether composite films as a communication substrate that could be applied under high frequency circumstances.

Label-Free Spectral Imaging Unveils Biochemical Mechanisms of Low-Level Laser Therapy on Spinal Cord Injury.

Background/aims: Low-level laser therapy (LLLT) leads to complex photochemical responses during the healing process of spinal cord injury (SCI). Confocal Raman Microspectral Imaging (in combination with multivariate analysis) was adopted to illustrate the underlying biochemical mechanisms of LLLT treatment on a SCI rat model.

Methods: Using transversal tissue sections, the Raman spectra can identify areas neighboring the injury site, glial scar, cavity, and unharmed white matter, as well as their correlated cellular alterations, such as demyelination and up-regulation of chondroitin sulfate proteoglycans (CSPGs).

946 nm Nd: YAG double Q-switched laser based on monolayer WSe saturable absorber.

In this paper, we report a 946nm double Q-switched laser side pumped by an 808-nm pulse laser diode (LD). A layered tungsten diselenide (WSe) saturable absorber (SA) together with an MgO doped LiNbO electro-optic (EO) modulator is applied to double Q-switch the Nd: YAG laser, producing trains of nanosecond-duration pulses with 500 Hz repetition rate. Such WSe saturable absorbers are fabricated by chemical vapor deposition (CVD) in a hot wall chamber and then embedded into a resonant mirror.