Search

The ultrastable encrypted storage of X-ray image with quantitative and ultrahigh-spatial resolution are crucial for a wide range of applications in radiation imaging, and it can be achieved by using the radio-photoluminescence (RPL) material, Ag-doped phosphate glass (Ag-PG), which was fabricated via the melt-quenching method. Under X-ray irradiation, Ag-PG produces a luminescence center, obvious 650 nm emission peak, which can be repeatedly excited by ultraviolet light without intensity attenuation. Quantitative X-ray image storage was realized based on the linear relationship between RPL intensity and X-ray irradiation time. X-ray image with a submicron spatial resolution of 0.7 µm was achieved, which could be stably stored without attenuation for more than 300 days. This submicron level X-ray image can be written into the Ag-PG as an encrypted information, and can only be visualized by an ultraviolet light. Additionally, heat treatment (400 °C for 2 h) could eliminate the influence of X-ray radiation on the Ag-PG, and restore the state of the Ag-PG before X-ray irradiation, which allows the recyclability and reusability of the Ag-PG. This research is of great significance for promoting the encrypted storage of X-ray images based on Ag-PG or other RPL materials. • The study demonstrated the ultrahigh-spatial-resolution and ultrastable X-ray image storage and encryption through Ag-PG. • The X-ray imaging at submicron scale is realized by using the Ag-PG, which could be stably stored for more than 300 days. • Ag-PG further realizes the anti-counterfeiting and encryption of X-ray image information with sub-micron level. • The Ag-PG exhibits important application potential in 3D X-ray imaging. [ABSTRACT FROM AUTHOR]

CsPbBr 3 nanoparticles uniformly distributed on reduced graphene oxide (rGO) to form CsPbBr 3 /rGO nanocomposites are synthesized by a facile method. Their corresponding optical and X-ray photon response are investigated. UV–visible absorption spectra and photoluminescence measurements confirm that loading CsPbBr 3 nanoparticles with an even distribution onto rGO surface can enhance the absorption and photon-generated carrier transportation. Thus, a significant enhancement in optical and X-ray photon response is demonstrated in CsPbBr 3 /rGO nanocomposites as compared with pure CsPbBr 3 nanoparticles. Clear conductive switching phenomenon with a state conversion between “on” and “off” is also observed under the intermittent x-ray exposure. These results may provide a new potential application of CsPbBr 3 /rGO nanocomposites for X-ray photon detection. [ABSTRACT FROM AUTHOR]

The free-carrier dynamics and nonlinear refractive index in bulk polycrystalline diamond are investigated using a femtosecond ultraviolet-pump-optical-probe technique with a phase object. Normalized transmittances under open-aperture and closed-aperture conditions are simultaneously measured to determine the dynamics of nonlinear absorption and refraction in the sample. In the dynamics of nonlinear absorption, three processes are clearly observed: nondegenerate two-photon absorption, fast and slower decay components of the free-carrier dynamics. The lifetimes of the free carriers are precisely measured. In the dynamics of nonlinear refraction, we obtain the nonlinear refractive coefficient and find that the results obtained under the femtosecond regime differ from those of other semiconducting materials previously measured under the picosecond regime. [ABSTRACT FROM AUTHOR]

During investigating water-compatible Lewis acids catalyzed etherifications using alcohols as alkylating reagents directly, we developed Fe(III)-catalyzed trityl benzyl ether formations irradiated by microwave. Then an in situ trityl benzyl ether formation and disproportionation cascade reaction was achieved to yield the benzaldehyde products with good functional group tolerances under neat conditions at relative higher temperatures. The substituent effects of the substrates on the etherification and disproportionation were explored by changing the substitutions on benzyl alcohols and triarylmethanols using chemical kinetic plots methods and the mechanism of the transformation was studied by crossover experiments. The etherification and disproportionation cascade process could be conveniently scaled up in laboratory without losing much efficiency. [ABSTRACT FROM AUTHOR]

Abstract: Imaging VISAR is an important diagnostic tool for a variety of shock-related phenomena in laser-driven experiments. To adapt to various types of shaped driven pulse, the imaging VISAR needs an illuminating light with good shaping capability. Here, a flexible laser probe system was experimentally studied. Being generated from a 1064-nm DFB laser, the continuous wave was modulated by a waveguide amplitude modulator driven by 10GS/s arbitrary waveform generator. After being amplified by fiber amplifiers and Nd:YAG rod amplifiers, the signal pulse was frequency-converted to 532-nm green light by a thermally controlled LBO crystal with a final output energy larger than 10mJ. Finally, the green light was coupled into a 1-mm core diameter, multimode fused silica optical fiber and propagated to the imaging VISAR. The probe laser could realize accurate pulse shaping with time resolution below 100ps. Uniformity in intensity and capability of arbitrary pulse shaping provides great convenience for the analysis of experimental data. [ABSTRACT FROM AUTHOR]