Browse Articles

Investigation of thermoelectric transport properties of <i>c</i>-axis oriented SnSb2Te4 thin-film fabricated using pulsed laser deposition technology

The van der Waals layered compound SnSb2Te4 has attracted intense attention as a promising thermoelectric material, yet its thin-film thermoelectric performance remains unexplored. In this study, we report the growth and thermoelectric properties of c-axis oriented SnSb2Te4 thin films using pulsed laser deposition technology. Systematic transport measurements revealed the strong correlation between deposition temperature, carrier concentration, and thermoelectric properties. Notably, the film deposited at 275 °C exhibited well-ordered crystalline structures with controlled orientation and superior thermoelectric performance, achieving a remarkable power factor of 8.3 µW cm−1 K−2 and a corresponding zT value of 0.18 at 575 K, demonstrating the great potential application of SnSb2Te4 thin films for micro-thermoelectric devices.

Enhanced colon-targeted drug delivery through development of 5-fluorouracil-loaded cross-linked mastic gum nanoparticles

Constructing Robust Electrode/Electrolyte Interphases for Highly Stable Lithium–Sulfurized Polyacrylonitrile Batteries

Abstract Lithium–sulfurized polyacrylonitrile (SPAN) batteries show great promise for energy storage, but are plagued by poor cycling stability, which can be attributed to unfavorable electrode/electrolyte interphases for both anode and cathode. Here we design and achieve the anion‐moderate solvation structure based interconnected clusters in electrolyte by regulating the interactions of solvent with Li + and diluent to construct robust anode/electrolyte and cathode/electrolyte interphases simultaneously for high‐performance Li–SPAN batteries. The optimal electrolyte endows Li plating/stripping with a high Coulombic efficiency of 99.47% at 1 mA cm −2 in Li||Cu cells. The Li–SPAN batteries show excellent cycling stability with a high capacity retention of 94.21% after 1215 cycles. Moreover, the assembled pouch‐type Li–SPAN battery under limited electrolyte condition (2.40 g Ah −1 ) achieves a capacity of 3.75 Ah, corresponding to a high energy density of 180 Wh kg −1 based on the total mass of the battery. This work provides a good electrolyte design principle to construct robust anode/electrolyte and cathode/electrolyte interphases for batteries.

Competing magnetic states in quasi-one-dimensional hexagonal ferromagnetic Nd1−xLaxCrGe3 crystals

Because of their unique crystal structure and peculiar physical properties, RECrGe3 (RE = La, Ce, Pr, Nd, and Sm) have attracted considerable research attention. Different to most of RECrGe3 crystals, usually showing a single phase transition, NdCrGe3 undergoes two distinct types of magnetic transitions from paramagnetic state to ferromagnetic (FM) and then to antiferromagnetic (AFM) state with lowering temperature. Here, we grew Nd1−xLaxCrGe3 (x = 0, 0.3, 0.6, and 0.9) samples and studied the structure and magnetic properties in detail. As the concentration of La increases, the AFM phase region of Nd1−xLaxCrGe3 (x = 0, 0.3, 0.6, and 0.9) show a dome-shaped evolution behavior. LaCrGe3 has been known to only display a low-temperature FM phase, which is attributed to the Cr magnetic moments. These current experimental results reveal a competition between the FM and AFM phases in this system and indicate that the Nd magnetic moments might play a key role in the AFM phase of NdCrGe3.

Ultrasonic prediction model using three-dimensional power doppler for endometrial cancer detection in women with postmenopausal bleeding

Room temperature low-loss etchless alumina ridge waveguides fabricated by pulsed laser deposition and lift-off

Alumina is a remarkable material for integrated photonics thanks to its broad transparency window spanning from ultraviolet to infrared, its low propagation losses, and its high solubility for rare-earth elements. However, conventional device fabrication processes, particularly those involving etching, often introduce significant optical losses, hindering the performance of high-quality alumina components. Pulsed laser deposition combined with a lift-off process offers an effective alternative, addressing the limitations of etching-based methods. In this paper, we present low-loss alumina waveguides in the visible and infrared spectral ranges, characterized using two distinct approaches. By evaluating the propagation losses in alumina thin films deposited under varying conditions and across different waveguide widths, we achieve losses as low as 2.0 dB/cm. This work demonstrates the potential of this technique for precise alumina structuring, paving the way for innovative rare-earth-doped alumina photonic devices.

Estimating liver cirrhosis severity with extracellular volume fraction by spectral CT

Development of millimeter-thick hexagonal boron nitride wafers and fast neutron detectors

We report the attainment of millimeter-thick neutron detectors fabricated from quasi-bulk hexagonal boron nitride (h-BN) produced by halide vapor phase epitaxy (HVPE). Detection efficiencies of 0.7% and 0.5% in response to neutrons emitted from bare AmBe and Cf-252 sources, respectively, have been achieved, corresponding to a charge collection efficiency of about 38%. These results mark a significant improvement over our previous single-stack h-BN detectors, which were 90 μm thick and exhibited a detection efficiency of 0.1%. This enhancement is primarily attributed to the increased thickness of the h-BN layer, leading to a higher intrinsic detection efficiency. We also observed that the carrier mobility-lifetime (μτ) product increases as layers of h-BN are successively removed from the top by polishing, indicating that a degradation in h-BN's electronic properties with thickness is now a major limiting factor for achieving high charge collection efficiency. This finding highlights the need for further refinement in HVPE growth processes to produce h-BN wafers with both larger thicknesses and improved electronic properties. Nevertheless, the fabrication of millimeter-thick single-stack h-BN neutron detectors represents a major milestone in the application of h-BN for fast neutron detection.

The regulation scheme of a double-rotor wind turbine during operation based on the transmission modes of rotors

Experimental realization of topological photonic quasicrystals with the eightfold rotational symmetry

The topological states in aperiodic systems have attracted extensive attention, which exhibit unique characteristics beyond the periodic structures. Photonic quasicrystals, exhibiting unlimited rotational symmetry, possess a remarkably rich and complex physics. Here, we construct an Ammann–Beenker tiling topological photonic quasicrystal with eightfold rotational symmetry by utilizing pure dielectric materials. The implemented experiments demonstrate the presence of a photonic bandgap and rotationally symmetric bulk state distribution and directly observe the corner and edge states within the photonic quasicrystal. Unlike conventional photonic crystals, these corner and edge states asymmetrically distribute along specific segments of the edges and strongly rely on the boundary geometry of the photonic quasicrystals. Our studies enrich the topological physics in the quasicrystal systems and provide a platform for exploring topological phases beyond the present topological classification of crystal structures.

Microstructural modeling of the fragmentation of ordinary chondrites

Integration of top-side low-temperature diamond on AlGaN/GaN RF HEMT for device-level cooling

Self-heating and related degradation in performance and reliability are serious concerns in realizing higher output power density in microwave power amplifiers. We demonstrated the integration of polycrystalline diamond on a fully fabricated metal-polar Schottky-gated AlGaN/GaN microwave transistor for the device-level cooling solution. The thermal budget of the diamond integration process is carefully optimized so as not to degrade the electrical performance of the device. Gate resistance thermometry measurement performed on a 1 × 200 μm2 device showed an average 111 °C lower channel temperature from 488 °C for the devices with diamond at 24 W/mm power dissipation than those without diamond. The gate leakage current of the device increased only by 4.8 times with the optimized diamond growth process. An extrinsic Ft/Fmax of 23/33 GHz was measured on devices with diamond compared to 23/36 GHz on devices without diamond. Diamond integration and gate leakage current modeling were also discussed on a 10-finger HEMT.

The sense of coherence scale and relationships between sense of coherence, sociodemographic variables and chronic disease

All-optical helicity-dependent switching in NiCo2O4 thin films

All-optical switching (AOS) involves manipulating magnetization using only a pulsed laser, presenting a promising approach for next-generation magnetic recording devices. NiCo2O4 (NCO) thin films, a rare-earth-free ferrimagnetic oxide, exhibit a high Curie temperature and strong perpendicular magnetic anisotropy. This study demonstrates AOS in NCO thin films at room temperature using long-duration laser pulses and high repetition rates. Unlike previous findings, the AOS phenomena we report here are helicity-dependent and observable with an ultrashort pulsed laser. Consequently, two distinct types of AOS can be observed in a single NCO thin film, contingent on the characteristics of the laser pulses and temperature.

ABCD parameter based analytical AC modeling of novel Cu–carbon hybrid interconnects for noise constrained nanoscale systems

LTC polarization-converted metamaterial based on hybrid EIT-like effect of bright-bright and bright-dark coupled modes

This paper proposes a high-efficiency linear to circular (LTC) polarization conversion metamaterial based on a multi-mode electromagnetically induced transparency-like (EIT-like) effect in the microwave band. The EIT-like transmission windows of bright-bright (B-B) and bright-dark (B-D) modes are constructed by generating multi-path excitation through an asymmetric structure. Then, the frequency shift and phase differences of the TE- and TM-polarized EIT-like windows are achieved by the perturbation method, which attributes to an LTC polarization conversion response with a high efficiency of 99.8%. The perturbation method also contributes to the insensitive performance for both EIT-like and LTC windows, corresponding to polarization angles of 240° and 120°, respectively. Finally, the proposed structure is fabricated and measured, and the simulation and experimental results are in good agreement.

Effect of delayed treatment on survival of patients with head and neck squamous cell cancer

Unveiling and eliminating the parasitic hole loss in AlGaN-based deep-ultraviolet light-emitting diodes

The parasitic hole loss during injection is experimentally unveiled in AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs), which is attributed to electron accumulation at the interface of active region and electron blocking layer. It is demonstrated that the loss arises mainly through the non-radiative recombination process, making it unnoticeable under normal operating conditions, e.g., at room temperature. A strategy of DUV-LEDs featuring the active region ending with a well layer is accordingly proposed to propel electron accumulation into the last quantum well. As a consequence, holes can be effectively injected into the wells without parasitic loss, where efficient radiative recombination for deep-ultraviolet emission occurs as hoped. The light output power is then enhanced by 23% at 100 mA in 277 nm DUV-LEDs. Meanwhile, the maximum wall-plug efficiency reaches 9.98% at 10 mA. The strategy in this study is compatible with the present commercial DUV-LED epitaxial structure, enabling it to promote further development of this field.

Adaptive yoga for psychological health of children having autism spectrum disorder and with intellectual disability: single case experimental design

Nonlinear opto-magnetic response of magnetic nanoparticles: Opto-magnetic particle spectroscopy

Opto-magnetic response of magnetic nanoparticles (MNPs) has been investigated as a means for rapid and sensitive biomolecule detection. However, current studies primarily focus on the linear opto-magnetic response of MNPs. In this study, we explore the nonlinear opto-magnetic response of MNPs induced in a sufficiently strong alternating-current (AC) magnetic field (≥3 mT) and under laser light, referred to as opto-magnetic particle spectroscopy (optoMPS). The underlying mechanism of the optoMPS signal is attributed to physical rotation of MNPs in an AC magnetic field and under laser light. Fokker–Planck equation is numerically solved to calculate the optoMPS signal while an optoMPS system is built for measurements. Experimental results show that the harmonic vs excitation frequency curve shifts to lower frequencies as the harmonic index increases. In addition, the optoMPS signal of MNP samples with different iron concentrations is measured to investigate the signal-to-noise ratio in AC magnetic fields with amplitudes ranging from 3 to 9 mT. Notably, the 2nd and 4th harmonics in an AC magnetic field with 9 mT allow for a limit-of-detection of 25 ng in terms of iron, paving the way for highly sensitive detection of MNPs with the optoMPS signal.