[en] Highlights: •A more facile approach is utilized to prepare the bi-continuous phases structured nanocomposite polymer electrolytes. •ATR-FTIR spectra show a competitive interaction between TiO₂ nanoparticles and Li⁺ ions, weakening the existing complexing action of ether-O…Li⁺, allowing Li⁺ ions faster transfer. •HRTEM shows the real dispersion state of TiO₂ nanoparticles in the PEO matrix: large aggregates rather than individual nanoparticles. -- Abstract: In this paper, inspired by the cubic bi-continuous gyroid structure self-assembled by block copolymers, we start with the application of a novel and more facile approach, compared to the tedious synthetic procedures of block copolymers, to prepare the bi-continuous phases structured nanocomposite electrolytes. The bi-continuous phase structure is composed of a hard phase of the electrospun poly vinylidene fluoride (PVDF) non-woven scaffold providing the mechanical support for the electrolyte membranes and another soft phase built up then by the infiltration of polyethylene oxide (PEO) electrolyte into the PVDF scaffold membrane to be the ionic conducting phase. Therefore, the nanocomposite polymer electrolytes of the bi-continuous phase structure are prepared with addition of the different amounts of TiO₂ nanoparticles into the PEO electrolyte (containing LiClO₄). The nanocomposite electrolyte membranes have systematically been characterized by scanning electron microscopy (SEM), differential scanning calorimeter (DSC), X-ray diffraction (XRD), and tensile test. The tensile results indicate that the infiltration of PEO phase into the PVDF scaffold can greatly improve the elongation of the electrolyte membrane at break, but the tensile strength of the electrolyte membrane is substantially dependent on the electrospun PVDF scaffold. The ionic conductivity measurements show that addition of TiO₂ nanoparticles with an appropriate amount of ca. 10 wt% enhances the ionic conductivity of the nanocomposite electrolytes to 7.60 × 10⁻⁵ S cm⁻¹ at 60 °C, compared to 8.33 × 10⁻⁶ S cm⁻¹ at 60 °C of the PEO–LiClO₄ electrolyte. The effect of TiO₂ nanoparticles on the enhancement of Li⁺ ion conductivity has been investigated by attenuated total reflectance-Fourier transform infrared spectra (ATR-FTIR), and the results show that a competitive interaction between TiO₂ nanoparticles and Li⁺ ions weakens to some extent the existing complexing action of ether-O…Li⁺, allowing Li⁺ ions faster transfer. However, we have found by high-resolution transmission electron microscopy (HRTEM) that the real dispersion state of TiO₂ nanoparticles in the nanocomposite electrolytes is in the form of large aggregates instead of the individual primary nanoparticles, which would tremendously depress the surface effect of the individual nanoparticles and greatly impact on the enhancement of the ionic conductivity

[en] Objective: To explore the clinical significance of serum IGF-1, CA153 and IL-8 levels in patients with breast cancer. Methods: The serum levels of IGF-I, CA153 and IL-8 in 36 patients with breast cancer, 40 patients with benign breast patients and 35 healthy controls were determined by RIA and ELISA respectively. Results: The serum levels of IGF-I, CA153 and IL-8 in patients with breast cancer were significantly higher than those in benign breast patient and controls (P < 0.01). The serum levels of IGF-I, CA153 and IL-8 in 15 breast cancer patients with lymph node metastasis were significantly higher than those in 21 breast cancer patients without lymph nodes metastasis (P < 0.01). Conclusion: The serum levels of IGF-I, CA153 and IL-8 might be used as markers in differential diagnosis of malignant from benign diseases, also might be helpful for lymph nodes metastasis prediction. (authors)

[en] Spin Hall nano oscillator (SHNO), a new type spintronic nano-device, can electrically excite and control spin waves in both nanoscale magnetic metals and insulators with low damping by the spin current due to spin Hall effect and interfacial Rashba effect. Several spin-wave modes have been excited successfully and investigated substantially in SHNOs based on dozens of different ferromagnetic/nonmagnetic (FM/NM) bilayer systems (e.g., FM = Py, [Co/Ni], Fe, CoFeB, Y₃Fe₅O₁₂; NM = Pt, Ta, W). Here, we will review recent progress about spin-wave excitation and experimental parameters dependent dynamics in SHNOs. The nanogap SHNOs with in-plane magnetization exhibit a nonlinear self-localized bullet soliton localized at the center of the gap between the electrodes and a secondary high-frequency mode which coexists with the primary bullet mode at higher currents. While in the nanogap SHNOs with out of plane magnetization, besides both nonlinear bullet soliton and propagating spin-wave mode are achieved and controlled by varying the external magnetic field and current, the magnetic bubble skyrmion mode also can be excited at a low in-plane magnetic field. These spin-wave modes show thermal-induced mode hopping behavior at high temperature due to the coupling between the modes mediated by thermal magnon mediated scattering. Moreover, thanks to the perpendicular magnetic anisotropy induced effective field, the single coherent mode also can be achieved without applying an external magnetic field. The strong nonlinear effect of spin waves makes SHNOs easy to achieve synchronization with external microwave signals or mutual synchronization between multiple oscillators which improve the coherence and power of oscillation modes significantly. Spin waves in SHNOs with an external free magnetic layer have a wide range of applications from as a nanoscale signal source of low power consumption magnonic devices to spin-based neuromorphic computing systems in the field of artificial intelligence. (review)

[en] We develop a splitting Chebyshev collocation (SCC) method for the time-dependent Schrödinger–Poisson (SP) system arising from theoretical analysis of quantum plasmas. By means of splitting technique in time, the time-dependant SP system is first reduced to uncoupled Schrödinger and Poisson equations at every time step. The space variables in Schrödinger and Poisson equations are next represented by high-order Chebyshev polynomials, and the resulting system are discretized by the spectral collocation method. Finally, matrix diagonalization technique is applied to solve the fully discretized system in one dimension, two dimensions and three dimensions, respectively. The newly proposed method not only achieves spectral accuracy in space but also reduces the computer-memory requirements and the computational time in comparison with conventional solver. Numerical results confirm the spectral accuracy and efficiency of this method, and indicate that the SCC method could be an efficient alternative method for simulating the dynamics of quantum plasmas.

[en] Artificial spin ice (ASI) structures have significant technological potential as reconfigurable metamaterials and magnetic storage media. We investigate the field/frequency-dependent magnetic dynamics of a kagome ASI made of 25-nm-thick permalloy nanomagnet elements, combining magnetoresistance (MR) and microscale ferromagnetic resonance (FMR) techniques. Our FMR spectra show a broadband absorption spectrum from 0.2 GHz to 3 GHz at H below 0.3 kOe, where the magnetic configuration of the kagome ASI is in the multidomain state, because the external magnetic field is below the obtained coercive field H _c ∼ 0.3 kOe, based on both the low-field range MR loops and simulations, suggesting that the low-field magnetization dynamics of kagome ASI is dominated by a multimode resonance regime. However, the FMR spectra exhibit five distinctive resonance modes at the high-field quasi-uniform magnetization state. Furthermore, our micromagnetic simulations provide additional spatial resolution of these resonance modes, identifying the presence of two high-frequency primary modes, localized in the horizontal and vertical bars of the ASI, respectively; three other low-frequency modes are mutually exclusive and separately pinned at the corners of the kagome ASI by an edge-induced dipolar field. Our results suggest that an ASI structural design can be adopted as an efficient approach for the development of low-power filters and magnonic devices. (paper)

[en] Flash flood disaster is a prominent issue threatening public safety and social development throughout the world, especially in mountainous regions. Rainfall threshold is a widely accepted alternative to hydrological forecasting for flash flood warning due to the short response time and limited observations of flash flood events. However, determination of rainfall threshold is still very complicated due to multiple impact factors, particular for antecedent soil moisture and rainfall patterns. In this study, hydrological simulation approach (i.e., China Flash Flood-Hydrological Modeling System: CNFF-HMS) was adopted to capture the flash flood processes. Multiple scenarios were further designed with consideration of antecedent soil moisture and rainfall temporal patterns to determine the possible assemble of rainfall thresholds by driving the CNFF-HMS. Moreover, their effects on rainfall thresholds were investigated. Three mountainous catchments (Zhong, Balisi and Yu villages) in southern China were selected for case study. Results showed that the model performance of CNFF-HMS was very satisfactory for flash flood simulations in all these catchments, especially for multimodal flood events. Specifically, the relative errors of runoff and peak flow were within ± 20%, the error of time to peak flow was within ± 2 h and the Nash–Sutcliffe efficiency was greater than 0.90 for over 90% of the flash flood events. The rainfall thresholds varied between 93 and 334 mm at Zhong village, between 77 and 246 mm at Balisi village and between 111 and 420 mm at Yu village. Both antecedent soil moistures and rainfall temporal pattern significantly affected the variations of rainfall threshold. Rainfall threshold decreased by 8–38 and 0–42% as soil saturation increased from 0.20 to 0.50 and from 0.20 to 0.80, respectively. The effect of rainfall threshold was the minimum for the decreasing hyetograph (advanced pattern) and the maximum for the increasing hyetograph (delayed pattern), while it was similar for the design hyetograph and triangular hyetograph (intermediate patterns). Moreover, rainfall thresholds with short time spans were more suitable for early flood warning, especially in small rural catchments with humid climatic characteristics. This study was expected to provide insights into flash flood disaster forecasting and early warning in mountainous regions, and scientific references for the implementation of flash flood disaster prevention in China.

[en] We investigate properties of perpendicular anisotropy magnetic tunnel junctions (pMTJs) with a stack structure MgO/CoFeB/Ta/CoFeB/MgO as the free layer (or recording layer), and obtain the necessary device parameters from the tunneling magnetoresistance (TMR) vs. field loops and current-driven magnetization switching experiments. Based on the experimental results and device parameters, we further estimate current-driven switching performance of pMTJ including switching time and power, and their dependence on perpendicular magnetic anisotropy and damping constant of the free layer by SPICE-based circuit simulations. Our results show that the pMTJ cells exhibit a less than 1 ns switching time and write energies < 1.4 pJ; meanwhile the lower perpendicular magnetic anisotropy (PMA) and damping constant can further reduce the switching time at the studied range of damping constant α < 0.1. Additionally, our results demonstrate that the pMTJs with the thermal stability factor ≃ 73 can be easily transformed into spin-torque nano-oscillators from magnetic memory as microwave sources or detectors for telecommunication devices. (paper)

[en] Among the layered two-dimensional ferromagnetic materials (2D FMs), due to a relatively high T _C, the van der Waals (vdW) Fe₃GeTe₂ (FGT) crystal is of great importance for investigating its distinct magnetic properties. Here, we have carried out static and dynamic magnetization measurements of the FGT crystal with a Curie temperature T _C ≈ 204 K. The M–H hysteresis loops with in-plane and out-of-plane orientations show that FGT has a strong perpendicular magnetic anisotropy with the easy axis along its c-axis. Moreover, we have calculated the uniaxial magnetic anisotropy constant (K ₁) from the SQUID measurements. The dynamic magnetic properties of FGT have been probed by utilizing the high sensitivity electron-spin-resonance (ESR) spectrometer at cryogenic temperatures. Based on an approximation of single magnetic domain mode, the K ₁ and the effective damping constant (α _eff) have also been determined from the out-of-plane angular dependence of ferromagnetic resonance (FMR) spectra obtained at the temperature range of 185 K to T _C. We have found large magnetic damping with the effective damping constant α _eff ∼ 0.58 along with a broad linewidth (Δ H _pp > 1000 Oe at 9.48 GHz, H ∥ c-axis). Our results provide useful dynamics information for the development of FGT-based spintronic devices. (paper)

[en] In recent years, flash floods and urban waterlogging have become a widespread phenomenon in Fuzhou, which pose a serious threat to people’s lives and property. The primary disaster-causing factors include the intensity and duration of rainfall. Therefore, this article analyzes the characteristics, causes of rainfall, and the existing problems of the two disasters in Fuzhou. The main conclusions are as follows: (1) The rainfall in Fuzhou is concentrated in March to September, with high rainfall intensity and rainfall amounts, and frequent extreme rainfall events combined with high rainfall intensity in flash flood-prone areas are higher than that in the plains area. (2) Precipitation, geographical conditions, and urban construction mainly caused the two major disasters and are weak in technology and management. Therefore, it is necessary to adhere to both the structural measures and non-structural measures to coordinate the relationship between people and floods, to strengthen the research on the mechanisms of precipitation, and to forecast and provide early warning of flash floods and urban waterlogging, all of which can provide reference for the defensive disasters in mountainous coastal cities.

[en] A new ZnTe modified TiO₂ nanotube (NT) array catalyst was prepared by pulse potential electrodeposition of ZnTe nanoparticles (NPs) onto TiO₂ NT arrays, and its application for photocatalytic degradation of anthracene-9-carboxylic acid (9-AnCOOH) was investigated. The even distribution of ZnTe NPs was well-proportionately grown on the top surface of the TiO₂ NT while without clogging the tube entrances. Compared with the unmodified TiO₂ NT, the ZnTe modified TiO₂ NT (ZnTe/TiO₂ NT) showed significantly enhanced photocatalytic activity towards 9-AnCOOH under simulated solar light. After 70 min of irradiation, 9-AnCOOH was degraded with the removal ratio of 45% on the bare TiO₂ NT, much lower than 80%, 90%, and 100% on the ZnTe/TiO₂ NT with the ZnTe NPs prepared under the pulsed 'on' potentials of -0.8, -1.0, and -2.0 V, respectively. The increased photodegradation efficiency mainly results from the improved photocurrent density as results of enhanced visible-light absorption and decreased hole-electron recombination due to the presence of narrow-band-gap p-type semiconductor ZnTe. -- Graphical abstract: Surface-view SEM images of ZnTe/TiO₂ NT prepared under -2.0 V, and the inset is the corresponding enlarged drawings. Display Omitted Research highlights: → A new method to deposit chalcogenides of transition metals on the TiO₂ nanotubes. → The even distribution of ZnTe nanoparticles was well-proportionedly grown onto TiO₂ NT arrays. → ZnTe/TiO₂ NT showed remarkably increased photocurrent density. → ZnTe/TiO₂ NT showed good photocatalytic performance. → The prepared new catalyst has a promising application in practical systems.