Interpreting the biochemical specificity of mouse spinal cord by confocal raman microspectral imaging

Interpreting the biochemical specifcity of spinal cord tissue is the essential requirement for underst.anding the biochemical mechanisms during spinal-cord-related pathological course.In this work,a longitudinal study was implemented to reveal a precise linkage betwoen the spectral features and the molecular composition in er vivo mouse spinal cord tissue by microspectral Raman imaging.It was testified that lipid-rich white matter could be distinguished from gray matter not only by the lipid Raman peaks at 1064,1300,1445 and 1660 cm^(-1),but also by protein(1250 and 1328 cm^(-1))and saccharides(913 and 1137 cm^(-1))distributions.K-means cluster analysis was further applied to visualize the morphological basis of spinal cord tissue by chemical components and their dist ribution patterns.T wo-dimensional chemical images were then generated to visualize the contrast between two different tissue types by integrating the intensitics of the featured Raman bands.All the obtained results ilustrated the biochemical characteristics of spinal cord tssue,as well as some specific substance variances bet ween different tssue types,which formed a solid basis for the molecular investigation of spinal cord pathologi cal alterations.

Simulation Studying Effects of Multiple Primary Aberrations on Donut-shaped Gaussian Beam

In this paper, we demonstrate the variation of donut-shaped depletion pattern which influenced by multiple primary aberrations. The simulation is base on a common stimulation emission of depletion (STED) system composed by Gaussian laser and vortex phase plate. The simulation results are helpful guidelines for analyzing the aberration of depletion patterns in real situations.

Dynamics of frequency detuning in a hybrid Er-doped mode-locked fiber laser

Frequency detuning of mode-locked fiber lasers displays many remarkable nonlinear dynamical behaviors.Here we report for the first time the evolution of pulses from mode-locking through period pulsation to Q-switched mode-locking for three fundamental cases.Our experiments are performed in a hybrid actively and passively amplitude-modulated all-fiber polarization-maintaining mode-locked fiber laser,where the amplitude modulation frequency artificially deviates from the fundamental frequency of the cavity.We design and numerically simulate the laser with coupled Ginzburg–Landau equations.The experimentally observed dynamics of the mode detuning process is discussed with the assistance of the fitted model and numerical simulations,showing the generalizability of the optical mode detuning variation process.Our work provides fundamental insights for understanding perturbations in nonlinear optical resonant cavities and expands the ideas for studying chaotic path theory in hybrid mode-locked fiber lasers.

Pulsed LD side-pumped MgO：LN electro-optic cavity-dumped 1123 nm Nd： YAG laser with short pulse width and high peak power

We report a cavity-dumped 1123 nm laser with narrow pulse width and high peak power by an Mg O: LN crystal electrooptic(EO) modulator. Based on the structural optimization design of a folded biconcave cavity using the 808 nm pulsed laser diode(LD) side-pumped ceramic Nd: YAG rod, output pulses with maximum pulse energy and peak power up to39.6 m J and 9.73 MW were obtained, corresponding to 100 Hz repetition rate and 4.07 ns pulse width. The instabilities of pulse width and pulse energy were ±1.55% and ±2.06%, respectively. At the highest repetition rate of 1 kHz, the pulse energy, pulse width, and peak power were 11.3 mJ, 5.05 ns, and 2.24 MW, respectively. The instabilities of pulse width and pulse energy were ±2.65% and ±3.47%, respectively.

Typical synergistic effect of graphite nanoplatelets and carbon nanotubes and its influence on polymer-based dielectric composites

Graphite nanoplatelets(GNPs)with their intrinsic two-dimensional structure make an excellent compromise of advantages of both graphite and graphene.Due to their outstanding inherent properties,GNPs have been widely used as the functional fillers to improve certain performances of polymer-based composites.However,the multi-layer stacked construction of GNPs could form aggregations easily,which limits their application in polymer-based dielectric composites.Here,the authors exhibit a polydimethylsilicone(PDMS)-based nanocomposite which loading equivalent carbon nanotubes(CNTs)and GNPs as co-loading fillers,whose dielectric properties are improved significantly.The composites were fabricated through a highly-shearing mechanical mixing process.During the mixing process,both intrinsic CNTs entanglements and GNPs stacked aggregation could be ameliorated due to the interaction between these two types of fillers.Compared with the GNPs solely loaded composites,a small quantity of CNTs addition endows GNPs/CNTs/PDMS ternary composites with a significantly decreased percolation threshold(f_(c)∼1.7 vol.%).Both GNPs and CNTs,these two representative conductive carbon constructions with high aspect ratios are able to effectively enhance the establishing efficiency of internal conductive network inner composites.These results indicate that the development of internal conductive network and dielectric performance of nanocomposites are able to be optimised through the strategy of taking advantage of the synergistic effect of multi-type fillers reasonably.

Enhancement of phase conjugation degenerate four-wave mixing using a Bessel beam

We report on the enhancement of phase conjugation degenerate four-wave mixing(DFWM) in hot atomic Rb vapor by using a Bessel beam as the probe beam. The Bessel beam was generated using cross-phase modulation based on the thermal nonlinear optical effect. Our results demonstrated that the DFWM signal generated by the Bessel beam is about twice as large as that generated by the Gaussian beam, which can be attributed to the extended depth and tight focusing features of the Bessel beam. We also found that a DFWM signal with reasonable intensity can be detected even when the Bessel beam encounters an obstruction on its way, thanks to the selfhealing property of the Bessel beam. This work not only indicates that DFWM using a Bessel beam would be of great potential in the fields of high-fidelity communication, adaptive optics, and so on, but also suggests that a Bessel beam would be of significance to enhance the nonlinear process, especially in thick and scattering media.