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<jats:title>Abstract</jats:title> <jats:p>We have proposed and constructed a few-mode fiber-based comb filter realized by dislocation splicing a few-mode long-period fiber grating (FM-LPFG) with single-mode fiber. From an all-fiber laser with the few-mode fiber-based comb filter, the generation of switchable single-, dual-, triple-, and quadruple-wavelength continuous light have been achieved. Moreover, wavelength switchable mode-locked pulses have been obtained with the increased pump power. In experiment, the output wavelength of the mode-locked fiber laser was changed from 1567.72 nm to 1571.04 nm, while the signal to noise ratio was maintained above 61 dB. The switchable multiwavelength CW and mode-locked all-fiber lasers have potentially important applications for fiber sensing, wavelength-division multiplexing and signal processing.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Sulfide solid electrolytes are widely regarded as one of the most promising technical routes to realize all-solid-state batteries (ASSBs) due to their high ionic conductivity and favorable deformability. <jats:italic>However</jats:italic>, the relatively high price of the crucial starting material, Li<jats:sub>2</jats:sub>S, results in high costs of sulfide solid electrolytes, limiting their practical application in ASSBs. To solve this problem, we develop a new synthesis route of Li<jats:sub>2</jats:sub>S via liquid-phase synthesis method, employing lithium and biphenyl in 1, 2-dimethoxyethane (DME) ether solvent to form a lithium solution as the lithium precursor. Because of the comparatively strong reducibility of lithium solution, its reaction with sulfur proceeds effectively even at room temperature. This new synthesis route of Li<jats:sub>2</jats:sub>S starts with cheap precursors of lithium, sulfur, biphenyl and DME solvent, and the only remaining byproduct (DME solution of biphenyl) after the collection of Li<jats:sub>2</jats:sub>S product can be recycled and reused. Besides, the reaction can proceed effectively at room temperature with mild condition, reducing energy cost to a great extent. The as-synthesized Li<jats:sub>2</jats:sub>S owns uniform and extremely small particle size, proved to be feasible in synthesizing sulfide solid electrolytes (such as the solid-state synthesis of Li<jats:sub>6</jats:sub>PS<jats:sub>5</jats:sub>Cl). Spontaneously, this lithium solution can be directly employed in the synthesis of Li<jats:sub>3</jats:sub>PS<jats:sub>4</jats:sub> solid electrolytes via liquid-phase synthesis method, in which the centrifugation and heat treatment processes of Li<jats:sub>2</jats:sub>S are not necessary, providing simplified production process. The as-synthesized Li<jats:sub>3</jats:sub>PS<jats:sub>4</jats:sub> exhibits typical Li<jats:sup>+</jats:sup> conductivity of 1.85×10<jats:sup>-4</jats:sup> S cm<jats:sup>-1</jats:sup> at 30℃.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>The effect of linear chirp frequency on the process of electron-positron pairs production from vacuum is investigated by the computational quantum field theory. With appropriate chirp parameters, the number of electrons created under combined potential wells can be increased by two or three times. In the low frequency region, frequency modulation excites interference effect and multiphoton processes, which promotes the generation of electron-positron pairs. In the high frequency region, high frequency suppression inhibits the generation of electron-positron pairs. In addition, for a single potential well, the number of created electron-positron pairs can be enhanced by several orders of magnitude in the low frequency region.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>In this work, the polarization characteristics of ultrathin CsPbBr<jats:sub>3</jats:sub> nanowires are investigated. Especially, for the height of cross-section of nanowires between 2 nm and 25 nm, the normalized intensity and polarization ratio <jats:italic>ρ</jats:italic> of CsPbBr<jats:sub>3</jats:sub> nanowires with triangular, square and hexagonal cross-section shapes are compared. The results show that, along with the increase of the height of cross-section, the polarization ratios of these three nanowires decrease until <jats:italic>T</jats:italic>=15 nm, and increase afterwards. Also, along with the increase of the cross-section area up to 100 nm<jats:sup>2</jats:sup>, the polarization ratios of these three nanowires increase too. In general, for the same height or area, the polarization ratio <jats:italic>ρ</jats:italic> of these nanowires follows <jats:italic>ρ</jats:italic> <jats:sub>hexagon</jats:sub> &gt; <jats:italic>ρ</jats:italic> <jats:sub>square</jats:sub> &gt; <jats:italic>ρ</jats:italic> <jats:sub>triangle</jats:sub>. Therefore, the nanowire with the hexagonal cross-section should be chosen, where for a cross-section height of 2 nm and a length-height ratio of 20:1, the maximal polarization ratio is 0.951 at the longitudinal center of the NW. Further, for the hexagonal NW with a cross-section height of 10 nm, the hexagonal NW with a length-height ratio of 45:1 exhibits the maximal polarization ratio at the longitudinal center of the NW. These simulation results predict the feasible size and shape of CsPbBr<jats:sub>3</jats:sub> nanowire devices with high polarization ratios.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>Studies of sustained oscillations on complex networks with excitable node dynamics received much interest in recent years. Although an individual unit is non-oscillatory, they may organize to form various collective oscillatory patterns through networked connections. An excitable network usually possesses a number of oscillatory modes dominated by different Winfree loops and numerous spatiotemporal patterns organized by different propagation path distributions. The traditional approach of the so-called dominant phase-advanced drive method has been well applied to the study of stationary oscillation patterns on a network. In this paper, we develop the functional-weight approach that has been successfully used in studies of sustained oscillations in gene-regulated networks by an extension to the high-dimensional node dynamics. This approach can be well applied to the study of sustained oscillations in coupled excitable units. We tested this scheme for different networks, such as homogeneous random networks, small-world networks, and scale-free networks and found it can accurately dig out the oscillation source and the propagation path. The present approach is believed to have the potential in studies competitive non-stationary dynamics.</jats:p>

<jats:p>High-temperature nuclear magnetic resonance (NMR) has proven to be very useful for detecting the temperature-induced structural evolution and dynamics in melts. However, the sensitivity and precision of high-temperature NMR probes are limited. Here we report a sensitive and stable high-temperature NMR probe based on laser-heating, suitable for <jats:italic>in situ</jats:italic> studies of metallic melts, which can work stably at the temperature of up to 2000 K. In our design, a well-designed optical path and the use of a water-cooled copper radio-frequency (RF) coil significantly optimize the signal-to-noise ratio (S/NR) at high temperatures. Additionally, a precise temperature controlling system with an error of less than ± 1 K has been designed. After temperature calibration, the temperature measurement error is controlled within ± 2 K. As a performance testing, <jats:sup>27</jats:sup>Al NMR spectra are measured in Zr-based metallic glass-forming liquid <jats:italic>in situ</jats:italic>. Results show that the S/NR reaches 45 within 90 s even when the sample’s temperature is up to 1500 K and that the isothermal signal drift is better than 0.001 ppm per hour. This high-temperature NMR probe can be used to clarify some highly debated issues about metallic liquids, such as glass transition and liquid–liquid transition.</jats:p>

<jats:p>We have grown a YCrO<jats:sub>3</jats:sub> single crystal by the floating-zone method and studied its temperature-dependent crystalline structure and magnetization by x-ray powder diffraction and PPMS DynaCool measurements. All diffraction patterns were well indexed by an orthorhombic structure with space group of <jats:italic>Pbnm</jats:italic> (No. 62). From 36 K to 300 K, no structural phase transition occurs in the pulverized YCrO<jats:sub>3</jats:sub> single crystal. The antiferromagnetic phase transition temperature was determined as <jats:italic>T</jats:italic> <jats:sub>N</jats:sub> = 141.58(5) K by the magnetization versus temperature measurements. We found weak ferromagnetic behavior in the magnetic hysteresis loops below <jats:italic>T</jats:italic> <jats:sub>N</jats:sub>. Especially, we demonstrated that the antiferromagnetism and weak ferromagnetism appear simultaneously upon cooling. The lattice parameters (<jats:italic>a</jats:italic>, <jats:italic>b</jats:italic>, <jats:italic>c</jats:italic>, and <jats:italic>V</jats:italic>) deviate downward from the Grüneisen law, displaying an anisotropic magnetostriction effect. We extracted temperature variation of the local distortion parameter <jats:italic>Δ</jats:italic>. Compared to the <jats:italic>Δ</jats:italic> value of Cr ions, Y, O1, and O2 ions show one order of magnitude larger <jats:italic>Δ</jats:italic> values indicative of much stronger local lattice distortions. Moreover, the calculated bond valence states of Y and O2 ions have obvious subduction charges.</jats:p>

<jats:p>To improve the stability and luminescence properties of CsPbBr<jats:sub>3</jats:sub> QDs, we proposed a new core-shell structure for CsPbBr<jats:sub>3</jats:sub>/CdSe/Al quantum dots (QDs). By using a simple method of ion layer adsorption and a reaction method, CdSe and Al were respectively packaged on the surface of CsPbBr<jats:sub>3</jats:sub> QDs to form the core-shell CsPbBr<jats:sub>3</jats:sub>/CdSe/Al QDs. After one week in a natural environment, the photoluminescence quantum yields of CsPbBr<jats:sub>3</jats:sub>/CdSe/Al QDs were greater than 80%, and the PL intensity remained at 71% of the original intensity. Furthermore, the CsPbBr<jats:sub>3</jats:sub>/CdSe/Al QDs were used as green emitters for white light-emitting diodes (LEDs), with the LEDs spectrum covering 129% of the national television system committee (NTSC) standard color gamut. The core-shell structure of QDs can effectively improve the stability of CsPbBr<jats:sub>3</jats:sub> QDs, which has promising prospects in optoelectronic devices.</jats:p>

<jats:p>The uneven spatial distribution of stations providing precipitable water vapor (PWV) observations in China hinders the effective use of these data in assimilation, nowcasting, and prediction. In this study, we proposed a complex network framework for exploring the topological structure and the collective behavior of PWV in the mainland of China. We used the Pearson correlation coefficient and transfer entropy to measure the linear and nonlinear relationships of PWV amongst different stations and to set up the undirected and directed complex networks, respectively. Our findings revealed the statistical and geographical distribution of the variables influencing PWV networks and identified the vapor information source and sink stations. Specifically, the findings showed that the statistical and spatial distributions of the undirected and directed complex vapor networks in terms of degree and distance were similar to each other (the common interaction mode for vapor stations and their locations). The betweenness results displayed different features. The largest betweenness ratio for directed networks tended to be larger than that of the undirected networks, implying that the transfer of directed PWV networks was more efficient than that of the undirected networks. The findings of this study are heuristic and will be useful for constructing the best strategy for the PWV data in applications such as vapor observational networks design and precipitation prediction.</jats:p>

<jats:p>Quantum controlled teleportation is the transmission of the quantum state under the supervision of a third party. This paper presents the theoretical and experimental results of an arbitrary two-qubit quantum controlled teleportation scheme, in which the sender Alice only needs to perform two Bell state measurements and the receiver Bob can perform an appropriate unitary operation to reconstruct the arbitrary two-qubit states under the control of the supervisor Charlie. The operation process of the scheme is verified on the IBM quantum experience platform, and the accuracy of the transmitted quantum state is further checked by performing quantum state tomography. Meanwhile, a good fidelity is obtained by using the theoretical density matrix and the experimental density matrix. A sequence of photonic states is introduced to analyze the possible intercept–replace–resend, intercept–measure–resend, and entanglement–measure–resend attacks on this scheme. The results proved that our scheme is highly secure.</jats:p>