Enhancing Thermoelectric and Cooling Performance of BiSbTe through Ferroelectric Polarization in Flexible Ag/PZT/PVDF/BiSbTe Film.

BiTe-based thin films are gaining recognition for their remarkable room temperature thermoelectric performance. Beyond the conventional "process-composition-performance" paradigm, it is highly desirable to explore new methods to enhance their performance further. Here, we designed a sandwich-structured Ag/PZT/PVDF/BiSbTe(BST) thin film device and effectively regulated the performance of the BST film by controlling the polarization state of the PZT/PVDF layers.

Thermal pattern of Tatun volcanic system by satellite-observed temperatures and its correlation with earthquake magnitudes.

The land surface temperature (LST) of volcanoes detected from satellite sensors reflects the thermal status of heat sources in the subsurface. Volcanic earthquakes occur as magma and volcanic fluids transport to the surface from depth. Thus, both LST and earthquake magnitude are key parameters to the study of active volcanoes.

Significant Enhancement of Thermoelectric Performance in Bi Sb Te Thin Film via Ferroelectric Polarization Engineering.

The Bi Sb Te (BST) thin film shows great promise in harvesting low-grade heat energy due to its excellent thermoelectric performance at room temperature. In order to further enhance its thermoelectric performance, specifically the power factor and output power, new approaches are highly desirable beyond the common "composition-structure-performance" paradigm. This study introduces ferroelectric polarization engineering as a novel strategy to achieve these goals.

Tracking interface position of a high-speed imploding composite liner based on magnetic diffusion difference.

A technique for tracking the interface position of non-metal-metal composite liners during high-speed implosion is proposed in this paper. Based on the magnetic diffusion difference between metal and non-metal, the interface position information is obtained by measuring magnetic fields in the cavity of the liner. An efficient magnetic flux estimation algorithm based on iterative magnetic diffusion simulation is also proposed to estimate the magnetic flux loss of the liner.

High buffering capacity cobalt-doped nickel hydroxide electrode as redox mediator for flexible hydrogen evolution by two-step water electrolysis.

Two-step water electrolysis has been proposed to tackle the ticklish H/O mixture problems in conventional alkaline water electrolysis recently. However, low buffering capacity of pure nickel hydroxide electrode as redox mediator limited practical application of two-step water electrolysis system. A high-capacity redox mediator (RM) is urgently needed to permit consecutive operation of two-step cycles and high-efficiency hydrogen evolution.

Three-dimensional ordered macroporous molybdenum doped NiCoP honeycomb electrode for two-step water electrolysis.

Two-step alkaline water electrolysis is considered a safe and efficient method for producing hydrogen from renewable energy. Reversal of the current polarity in a bifunctional electrocatalyst used as a gas evolution electrode (GEE) in two-step water electrolysis can generate H/O at different times and in different spaces. The design of a bifunctional electrocatalyst with high durability and excellent activity is imperative to achieving continuous, safe, and pure H generation via two-step alkaline water electrolysis.

A compact pulsed power driver with precisely shaped current waveforms for magnetically driven loading experiments.

Magnetically driven loading techniques based on high current pulsed power drivers are very important tools for researching material dynamic behaviors and high-pressure physics. Based on the technologies of a Marx generator energy storage and low impedance coaxial cable energy transmission, a compact high current pulsed power driver CQ-7 was developed and established at the Institute of Fluid Physics, China Academy of Engineering Physics, which can generate precisely shaped current waveforms for magnetically driven loading experiments. CQ-7 is composed of 256 two-stage Marx generators in parallel with low impedance, high voltage coaxial cables for current output.

Development of a transient complex impedance measurement device used in quasi-isentropic compression experiments.

A complex impedance measurement device with a short response time and high noise immunity is presented in this paper. The device based on a radio-frequency reflectometer was specially developed for electro-physical property investigations of materials in quasi-isentropic compression experiments. The maximum operating frequency of the device is up to 600 MHz for reducing intense low-frequency noises.

A compact platform for the investigation of material dynamics in quasi-isentropic compression to ~ 19 GPa.

This paper reports on the development of a magnetically driven high-velocity implosion experiment conducted on the CQ-3 facility, a compact pulsed power generator with a load current of 2.1 MA. The current generates a high Lorentz force between inner and outer liners made from 2024 aluminum.

Hydrogen Clathrate Structures in Uranium Hydrides at High Pressures.

Room-temperature superconductivity has always been an area of intensive research. Recent findings of clathrate metal hydrides structures have opened up the doors for achieving room-temperature superconductivity in these materials. Here, we report first-principles calculations for stable H-rich clathrate structures of uranium hydrides at high pressures.

Three dimensional flower-like magnetic polyethyleneimine@MoS composites for highly efficient removal of Cr(VI) and Pb(II) ions.

Magnetic FeO nanoparticles were coated by polyethyleneimine (PEI), and then FeO@PEI was further modified with MoS by the hydrothermal method to fabricate 3D flower-like structured magnetic polyethyleneimine@MoS (MP@MoS) composites, and the composites were served as efficient adsorbents to capture Cr(VI) and Pb(II) from aqueous solution. The effects of temperature, pH, shaking time and environmental conditions on adsorption performance of MP@MoS towards Cr(VI) and Pb(II) have been conducted by batch adsorption experiments. The prepared MP@MoS exhibited high adsorption capacities (192.

Temperature effect on the phase stability of hydrogen2/phase from first-principles molecular dynamics calculations.

The structural stability of hydrogen2/phase from 0 K to 300 K is investigated by combining the first-principles molecular dynamics (MD) simulations and density functional perturbation theory. Without considering the temperature effect, the2/phase is stable from 150 GPa to 250 GPa based on the harmonic phonon dispersion relations. The hydrogen molecules at the solid lattice sites are sensitive to temperature.

Continuous Sound Velocity Measurements along the Shock Hugoniot Curve of Quartz.

We report continuous measurements of the sound velocity along the principal Hugoniot curve of α quartz between 0.25 and 1.45 TPa, as determined from lateral release waves intersecting the shock front as a function of time in decaying-shock experiments.

Coupled-resonator-induced plasmonic bandgaps.

By drawing an analogy with the conventional photonic crystals, the plasmonic bandgaps have mainly employed the periodic metallic structures, named as plasmonic crystals. However, the sizes of the plasmonic crystals are much larger than the wavelengths, and the large sizes considerably decrease the density of the photonic integration circuits. Here, based on the coupled-resonator effect, the plasmonic bandgaps are experimentally realized in the subwavelength waveguide-resonator structure, which considerably decreases the structure size to subwavelength scales.

Self-reference plasmonic sensors based on double Fano resonances.

High-sensitivity plasmonic refractive index sensors show great applications in the areas of biomedical diagnostics, healthcare, food safety, environmental monitoring, homeland security, and chemical reactions. However, the unstable and complicated environments considerably limit their practical applications. By employing the independent double Fano resonances in a simple metallic grating, we experimentally demonstrate a self-reference plasmonic sensor, which significantly reduces the error contributions of the light intensity fluctuations in the long-distance propagation and local temperature variations at the metallic grating, and the detection accuracy is guaranteed.

Controlling surface-plasmon-polaritons launching with hot spot cylindrical waves in a metallic slit structure.

Plasmonic nanostructures, which are used to generate surface plasmon polaritons (SPPs), always involve sharp corners where the charges can accumulate. This can result in strong localized electromagnetic fields at the metallic corners, forming the hot spots. The influence of the hot spots on the propagating SPPs are investigated theoretically and experimentally in a metallic slit structure.

Visible-Frequency Dielectric Metasurfaces for Multiwavelength Achromatic and Highly Dispersive Holograms.

Dielectric metasurfaces built up with nanostructures of high refractive index represent a powerful platform for highly efficient flat optical devices due to their easy-tuning electromagnetic scattering properties and relatively high transmission efficiencies. Here we show visible-frequency silicon metasurfaces formed by three kinds of nanoblocks multiplexed in a subwavelength unit to constitute a metamolecule, which are capable of wavefront manipulation for red, green, and blue light simultaneously. Full phase control is achieved for each wavelength by independently changing the in-plane orientations of the corresponding nanoblocks to induce the required geometric phases.

A high current pulsed power generator CQ-3-MMAF with co-axial cable transmitting energy for material dynamics experiments.

A high current pulsed power generator CQ-3-MMAF (Multi-Modules Assembly Facility, MMAF) was developed for material dynamics experiments under ramp wave and shock loadings at the Institute of Fluid Physics (IFP), which can deliver 3 MA peak current to a strip-line load. The rise time of the current is 470 ns (10%-90%). Different from the previous CQ-4 at IFP, the CQ-3-MMAF energy is transmitted by hundreds of co-axial high voltage cables with a low impedance of 18.

Tuning Fano resonances with a nano-chamber of air.

By designing a polymer-film-coated asymmetric metallic slit structure that only contains one nanocavity side-coupled with a subwavelength plasmonic waveguide, the Fano resonance is realized in the experiment. The Fano resonance originates from the interference between the narrow resonant spectra of the radiative light from the nanocavity and the broad nonresonant spectra of the directly transmitted light from the slit. The lateral dimension of the asymmetric slit is only 825 nm.

Efficient unidirectional launching of surface plasmons by a cascade asymmetric-groove structure.

Increasing the unidirectional launching efficiency of surface plasmon polaritons (SPPs) is crucial in plasmonics. Here, we demonstrate that this efficiency may be improved by cascading subwavelength unidirectional SPP launching units. A unidirectional SPP launching efficiency of at least 46% and an extinction ratio of 40 are experimentally demonstrated using a cascade asymmetric-groove structure.

Plasmonic ridge waveguides with deep-subwavelength outside-field confinements.

Subwavelength plasmonic waveguides are the most promising candidates for developing planar photonic circuitry platforms. In this study a subwavelength metallic ridge waveguide is numerically and experimentally investigated. Differing from previous plasmonic waveguides, the metallic strip of the subwavelength ridge waveguide is placed on a thick metal film.

An ultrahigh-contrast and broadband on-chip refractive index sensor based on a surface-plasmon-polariton interferometer.

Using a double-slit structure fabricated on a gold film or a subwavelength (300 nm) plasmonic waveguide, high-contrast and broadband plasmonic sensors based on the interference of surface plasmon polaritons (SPPs) are experimentally demonstrated on chips. By adjusting the focused spot position of the p-polarized incident light on the double-slit structure to compensate for the propagation loss of the SPPs, the interfering SPPs from the two slits have nearly equal intensities. As a result, nearly completely destructive interference can be experimentally achieved in a broad bandwidth (>200 nm), revealing the robust design and fabrication of the double-slit structure.

Manipulating surface-plasmon-polariton launching with quasi-cylindrical waves.

Launching the free-space light to the surface plasmon polaritons (SPPs) in a broad bandwidth is of importance for the future plasmonic circuits. Based on the interference of the pure SPP component, the bandwidths of the unidirectional SPP launching is difficult to be further broadened. By greatly manipulating the SPP intensities with the quasi-cylindrical waves (Quasi-CWs), an ultra-broadband unidirectional SPP launcher is experimentally realized in a submicron asymmetric slit.

Efficient directional excitation of surface plasmons by a single-element nanoantenna.

Directional light scattering is important in basic research and real applications. This area has been successfully downscaled to wavelength and subwavelength scales with the development of optical antennas, especially single-element nanoantennas. Here, by adding an auxiliary resonant structure to a single-element plasmonic nanoantenna, we show that the highly efficient lowest-order antenna mode can be effectively transferred into inactive higher-order modes.

Ultra-small wavelength splitters in a subwavelength plasmonic waveguide.

Miniaturizing optical devices beyond the diffraction limit is of great importance for high-integration photonic circuits. By directly fabricating a double-slit aperture structure of different sizes in a subwavelength plasmonic waveguide, an ultra-small plasmonic wavelength splitter is realized experimentally. Due to the different slit widths, the surface plasmon polaritons (SPPs) in the opposite directions exhibit anti-phase interferences.