Transparent KF-ZnF(2)-SiO(2) glass-ceramics were prepared with the precipitation of KZnF(3)Ni(2+) nanocrystals. During excitation with a wavelength of 405 nm at room temperature, a broadband near-IR emission centered at 1695 nm with the FWHM of more than 350 nm was observed, which is originated from the T(2g)3(F3)→A(2g)3(F3) transition of octahedral Ni(2+) incorporated in the KZnF(3) crystalline phase. In comparison to oxide glass-ceramics, a redshift of the luminescence is observed, which is due to the low crystal field of these octahedral Ni(2+). The shift and extension of near-IR emission in the KZnF(3):Ni(2+) nanocrystals embedded in a glassy matrix do not only complete the broadband emission in the whole near-IR region for the Ni(2+) ions-based photonics, but also open an easy way to approach the broadband optical amplifier and tunable lasers operating in the wavelength region near 1800 nm, which was up to now achieved by codoping of several types of active ions.
This paper proposes a convolutional neural network (CNN) method to estimate subsurface temperature (ST) in the Pacific Ocean from a suite of satellite remote sensing measurements. These include sea surface temperature(SST), sea surface height (SSH), and sea surface salinity (SSS). We propose using the multisource sea surface parameters to establish a monthly CNN model to reconstruct the ocean subsurface temperature (ST) and use Argo data for accurate validation. The results show that the CNN can accurately estimate the ST of the Pacific Ocean by using the model. We trained the model for 12 months. The most prominent months are January, April, July, and October with average mean square error (MSE) values of 0.2659, 0.3129, 0.5318, and 0.5160, and the average coefficients of determination (R 2 ) were 0.968, 0.971, 0.949, and 0.967, respectively. This study improves the accuracy of ST estimation and the good results based on reanalysis indicate that the model is promising to be applied to satellite observations. INDEX TERMS Convolutional neural network, ocean data, satellite measurements, subsurface temperature.
PbS QDs of~5nm diameter were precipitated in glasses containing Ag nanoparticles after 3 min of 1.5-W continuous-wave laser illumination at k = 532 nm. Photoluminescence spectra of the PbS QDs recorded in the 1.3~1.6 lm wavelength region revealed conversion of photon energy to thermal energy by surface plasmon resonance. Laser-assisted local heating around Ag NPs can provide a new method to control the spatial distribution of QDs in glasses.
Cesium lead halide (CsPbX3, X = Cl, Br, and I) perovskite nanocrystals (NCs) exhibit efficient anti‐Stokes photoluminescence (ASPL) upon sub‐gap single‐photon excitation, which has great potential for all‐solid‐state laser cooling. However, the mechanism responsible for the ASPL still remains elusive. Here, ASPL properties of CsPb(BrI)3 NCs and CsPbI3 NCs in inorganic solid matrix are investigated. Excitation wavelength‐ and power‐dependent ASPL demonstrates that it is a phonon‐assisted single‐photon process. Femtosecond transient absorption spectra show that ASPL is mediated by the Urbach tail states, where localized excitons are generated upon sub‐gap excitation. Through electron–phonon coupling, these localized excitons change into free exciton to generate the exciton bleaching, and then thermally dissociate into free carriers accompanied by band edge bleaching, leading to the efficient ASPL. Such a two‐step up‐conversion process is further confirmed by the carrier temperature extracted from the band edge bleaching band. This work deepens the understanding of ASPL in CsPbX3 NCs, and is valuable for the development of materials for solid‐state laser cooling.
We report the characterization of the compound [K([2.2.2]crypt)]4[In8Sb13], which proves to contain a 1:1 mixture of [Sb@In8Sb12]3− and [Sb@In8Sb12]5−. The tri‐anion displays perfect Th symmetry, the first completely inorganic molecule to do so, and contains eight equivalent In3+ centers in a cube. The gas‐phase potential energy surface of the penta‐anion has eight equivalent minima where the extra pair of electrons is localized on one In+ center, and these minima are linked by low‐lying transition states where the electron pair is delocalized over two adjacent centers. The best fit to the electron density is obtained from a model where the structure of the 5− cluster lies close to the gas‐phase transition state.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.