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Self-catalyzed vapor–liquid–solid growth of GaS nanobelt for nano-optoelectronic applications
GaS, with the largest bandgap of group III–VI van der Waals semiconductors, is a potential building block of optoelectronic applications. In addition, one-dimensional structures, such as nanobelts, are preferable for integration into future nano-optoelectronic devices. Here, we demonstrated self-catalyzed vapor–liquid–solid (VLS) growth of a GaS nanobelt by metalorganic chemical vapor deposition. Ga-rich growth conditions caused Ga particles to be generated in the initial growth step. The nanobelt grew from a Ga particle, which acted as a catalyst. The fabricated nanobelt photodetector showed a high ON/OFF ratio and the dark current was under the detection limit. Moreover, compared with an exfoliated GaS flake photodetector, it had one order of magnitude higher responsivity. These outstanding photoresponse properties indicate that self-catalyzed VLS growth of GaS nanobelts is a promising bottom-up integration approach for nano-optoelectronic applications.
Twisted metamaterials for mechanical optical switch
The emergence of twisted metamaterials opens up an avenue for research in metamaterials. However, the current emphasis primarily lies in mechanics, rendering it intriguing to explore the application of compression-torsion coupling effect in optics. This present study introduces a thin-walled circular tube (TWCT) structure, characterized by a pronounced twisting angle of up to 59.5°, achieved only through a single-layer TWCT configuration. We demonstrate a significant compression-torsion coupling phenomenon, surpassing the findings of previous research endeavors. TWCT's deformation mechanism is harnessed in optical imaging through the integration of experimental, theoretical, and finite element approaches. The information stored in TWCT can be gradually projected through optical imaging when the elastic strain stimulates TWCT. These findings presented herein introduces a straightforward and valid approach to employ TWCT as a reliable mechanical switch for optical imaging, thereby showcasing its potential in the fields of cryptographic techniques, information storage, and transmission via optical imaging.
Improved light absorption enables highly efficient carbon dots luminescent solar concentrator
Carbon dots (CDs) offer several advantages, including non-toxicity, facile synthesis, high fluorescence efficiency, and large Stokes shift, rendering them up-and-coming candidates for luminescent solar concentrators (LSCs). However, the inherently weak light absorption of CDs significantly hinders LSC performance. Here, by modifying the space-confined vacuum heating method, we synthesized high quantum yield CDs with increased size and improved absorption cross section (up to 2.7 times greater than the smaller counterparts), which was elucidated by the size-dominated non-resonant absorption mechanism. The enhanced absorptivity at reduced concentration was demonstrated to mitigate aggregation-induced quenching effectively. Furthermore, we designed a multi-film coating structure to block and recycle the transmitted harmful ultraviolet and short-wavelength blue light through optical interference, thereby fully exploiting this ‘useless’ waveband. By optimizing both the CD absorption cross section and the blue light recycling, the fabricated 80 × 80 × 2.5 mm3 LSC device achieved a record-high external optical efficiency of 9.6%, while still maintaining 71% average visible transmittance. This work proves the substantial potential of enhancing the efficiency of CD-based LSC devices from the perspective of light absorption.
Programmable surface-charge-modulated wettability for controllable droplet manipulation
Droplet manipulation on open surfaces plays a key role in numerous applications. The enhancement in controllability, flexibility, and simplicity of droplet manipulation is sustainably demanded and developed. Herein, we create a unique droplet manipulation method by modulating wettability based on surface charges. With contactless charge deposition on tilting dielectric surfaces with the corona discharge generated by needle-plate electrodes, droplet sliding can be actuated in real time. Droplets show wettability enhancement after eliminating charge deposition, in which contact angle decreases reach up to ∼20°. The presented surface-charge-modulated wettability results in fast-speed (∼14 mm/s) and high-volume-range (10–80 μL) droplet manipulation. Experiments and theoretical analysis reveal the underlying mechanism of droplet actuation is surface charge gradients, which induce asymmetric electrostatic forces. Controlling charge distributions on dielectric surfaces with plate-electrode patterns, programmable, and reconfigurable droplet sliding along complex pathways can be achieved. Moreover, a droplet sliding value for controlling stepwise chemical reactions is demonstrated by moving plate electrodes.
Transport properties of h-BN lateral devices
One of the well-established and significant applications of hexagonal boron nitride (h-BN) is in solid-state neutron detectors, which necessitate the development of quasi-bulk h-BN crystals. To advance the material and device development of h-BN, it is essential to characterize its bulk electrical transport properties. However, this task is challenging due to h-BN's ultrawide bandgap (UWBG) of approximately 6.1 eV, which results in an extremely high electrical resistivity, typically exceeding 1012 Ω⋅cm. On the other hand, the mobility-lifetime (μτ) product, a key figure of merit for determining the overall device performance, is more readily accessible through the characterization of the I-V characteristics under illumination. In this study, we investigate the in-plane μτ products of lateral devices fabricated from freestanding quasi-bulk h-BN wafers synthesized by hydride vapor phase epitaxy. Our results reveal an unexpected decrease in the in-plane μτ product as the device width decreases. Utilizing a simple two-region carrier transport model, where the central region of the device represents the bulk h-BN material free from metal contacts and the two edge regions are influenced by metal contacts, we demonstrate that the μτ product in the edge areas covered by metal contacts decreases by nearly two orders of magnitude compared to the bulk value. We attribute this significant reduction in μτ product to the layered crystalline structure of h-BN, which permits metal atoms to infiltrate into the interlayer spacings. As a result, the measured μτ product is significantly lower than the true bulk value. These findings provide valuable insights into the design and fabrication of high-performance h-BN devices, which typically leverage its exceptional in-plane transport properties.
Monolithic on-chip integration of micro-thin film thermocouples on multifinger gallium oxide MOSFETs
Gallium oxide (Ga2O3), with its ultra-wide bandgap (>4.5 eV), is a key material for the next-generation power electronics due to its high breakdown voltage and efficient power-switching capabilities. Multifinger (MF) Ga2O3 MOSFETS, designed to enhance current handling and thermal management, experience significant self-heating effects that can lead to localized hotspots, thermal runaway, and reduced device reliability. Accurate thermal characterization is therefore critical to ensure the reliable operation and longevity of such devices. Conventional methods, such as thermoreflectance imaging, Raman thermometry, and infrared thermography, are limited by complex setups, slow response times, resolution constraints, and cost, making them less practical for real-time, on-chip applications. On-chip thermal characterization directly at the active regions of the device provides an unparalleled opportunity to overcome these limitations by capturing localized temperature variations during operation. In this study, we demonstrate the integration of micro-thin film thermocouples (micro-TFTCs) onto multifinger Ga2O3 MOSFETs for precise, real-time, and localized thermal monitoring. The sensors captured temperature variations across different gate fingers, with the measured maximum channel temperature reaching 40.5 °C under peak power dissipation. Predicted thermal behavior under high power densities shows temperatures rising to approximately 80 °C at 5 W/mm2, illustrating the thermal challenges faced by Ga2O3 devices. This work demonstrates that micro-TFTCs are not only compatible with complex device architectures but also highly effective for localized thermal characterization, making them a promising tool for improving the thermal management and reliability of Ga2O3-based power electronics.
Publisher's Note: “A phononic crystal waveguide using surface waves below the sound cone” [Appl. Phys. Lett. <b>126</b> , 022204 (2025)]
Nonradiative quenching of EPR signals in germanium-doped AlGaN: Evidence for <i>DX</i>-center formation
We present photo-electron paramagnetic resonance (EPR) measurements and first-principles calculations that indicate germanium (Ge) is a DX center in AlGaN. Our photo-EPR measurements on Ge-doped AlGaN samples show no EPR spectra in the dark, while persistent EPR spectra are observed upon photoexcitation with photon energies greater than ∼1.3 eV. Thermally annealing the samples decreased the EPR signal, with the critical temperature to quench the EPR signal being larger in the lower Al-content sample. Using detailed first-principles calculations of Ge in AlGaN, we show all of these observations can be explained by accounting for the DX configuration of Ge in AlGaN.
Penetration of ionization wave through dielectric microhole in atmospheric pulsed discharges
Microstructure-enhanced discharges are critical for achieving higher plasma electron density and energy, offering significant potential in advanced plasma applications. A two-dimensional fluid model of pulsed dielectric barrier discharge was developed in atmospheric helium with a dielectric microhole. Two distinct high-electron-density regions, the T-region and L-region, were identified, driven, respectively, by transverse and longitudinal electric fields as the ionization wave traversed the microhole. The axisymmetric T-region is approached and squeezed as the radius decreases, in which the discharge intensity and electron density are enhanced. Based on the electron reaction source item, a virtual electrode is proposed in the dielectric microhole, which segregates the T- and L-regions. The width of the virtual electrode decreases with the microhole radius, and the virtual electrode extinguishes with the discharge ignition in the lower chamber and the formation of ionization wave in the dielectric microhole. These findings offer insights into plasma behavior in microstructures for advanced applications.
Tilting deformation analysis and instability prediction of arch-locked-segment landslides induced by rainfall
Abstract The failure of locked-segment landslides is associated with the destruction of locked segments that exhibit an energy accumulation effect. Thus, understanding their failure mode and instability mechanism for landslide hazard prevention and control is critical. In this paper, multiple instruments, such as tilt sensors, pore water pressure gauges, moisture sensors, matrix suction sensors, resistance strain gauges, miniature earth pressure sensors, a three-dimensional (3D) laser scanner, and a camera, were used to conduct the physical model tests on the rainfall-induced arch locked-segment landslide to analyze the resulting tilting deformation and evolution mechanism. The results indicate that the tilting deformation characteristics in the locked segment are consistent with the variation in its strain, stress, hydrodynamic responses, and slope morphology, suggesting that tilting deformation can serve as a novel monitoring approach for landslide instability. Further, the tangent angle method and the tilting rate reciprocal method can be utilized to predict the landslide instability based on the landslide tilting deformation curve. The effectiveness of this method is validated in the Huangzangsi dam area, which provides theoretical foundations for understanding the catastrophic mechanism and instability prediction of arch-locked-segment landslides.
Towards higher electro-optic response in AlScN
Novel materials with large electro-optic (EO) coefficients are essential for developing ultra-compact broadband modulators and enabling effective quantum transduction. Compared to lithium niobate, the most widely used nonlinear optical material, wurtzite AlScN, offers advantages in nano-photonic devices due to its compatibility with integrated circuits. We perform detailed first-principles calculations to investigate the electro-optic effect in Al1−xScxN alloys and superlattices. At elevated Sc concentrations in alloys, the EO coefficients increase; importantly, we find that cation ordering along the c axis leads to enhanced EO response. Strain engineering can be used to further manipulate the EO coefficients of AlScN films. With applied in-plane strains, the piezoelectric contributions to the EO coefficients increase dramatically, even exceeding 250 pm/V. We also explore the possibility of EO enhancement through superlattice engineering, finding that nonpolar a-plane (AlN)m/(ScN)n superlattices increase EO coefficients beyond 40 pm/V. Our findings provide design principles to enhance the electro-optic effect through alloy engineering and heterostructure architecture.
Cross-sectional study of proteomic differences between moderate and severe psoriasis
Examining the relationships between self-stigma, loneliness, depressive symptoms, and suicidal ideation among people with bipolar disorder
Relationship between functional structures and horizontal connections in macaque inferior temporal cortex
Abstract Horizontal connections in anterior inferior temporal cortex (ITC) are thought to play an important role in object recognition by integrating information across spatially separated functional columns, but their functional organization remains unclear. Using a combination of optical imaging, electrophysiological recording, and anatomical tracing, we investigated the relationship between stimulus-response maps and patterns of horizontal axon terminals in the macaque ITC. In contrast to the “like-to-like” connectivity observed in the early visual cortex, we found that horizontal axons in ITC do not preferentially connect sites with similar object selectivity. While some axon terminal patches shared responsiveness to specific visual features with the injection site, many connected to regions with different selectivity. Our results suggest that horizontal connections in anterior ITC exhibit diverse functional connectivity, potentially supporting flexible integration of visual information for advanced object recognition processes.
Fabrication of a poly(m‑aminophenol)/3-aminopropyl triethoxysilane/graphene oxide ternary nanocomposite for removal of Cu(II) from aqueous solution
Abstract Three composites based on Poly (meta-aminophenol) (PmAP), (3-aminopropyl) triethoxysilane (APTES) and graphene oxide (GO) were synthesized with initial GO dispersion of 3.3, 6.6, and 9.9 mg/mL. First, in-situ polymerization of meta-aminophenol monomer on the surface of graphene oxide (GO) was carried out. Then, the hydroxyl groups of both the GO and the polymer were targeted using (3-aminopropyl) triethoxysilane (APTES) to stop the polymer solubility, increase adsorption sites, and bind the two components. The obtained three composites were applied for efficient removal of Cu(II) from polluted water. PmAP/APTES/GO(6.6) composite was the best one for the uptake of Cu(II) with a maximum adsorption capacity of 324.54 mg/g at 40 °C and pH 7 according to Langmuir. PmAP/APTES/GO(6.6) hybrid composite was characterized by different techniques. The adsorption of Cu(II) on this composite was optimized under various experimental conditions. Furthermore, the isotherm data of the uptake of Cu(II) on PmAP/APTES/GO(6.6) were found to agree with the Freundlich and Langmuir model’s linear and nonlinear forms. Chemosorption was suggested by the Dubinin-Radushkevich (D-R) isotherm model as the calculated mean sorption energy exceeds 16 kJ/mol. The thermodynamic analysis of the adsorption process reflects an endothermic, spontaneous process that leads to more disorder at the solid-liquid interface. The chemical interactions between Cu(II) versus oxygen and nitrogen of the functional groups on the surface were demonstrated by X-ray Electron Spectroscopy (XPS). Five cycles of adsorption and desorption of Cu(II) from the prepared composite were carried out with a loss of only 6.3% of its adsorption capacity.
KAT2B inhibits proliferation and invasion via inactivating TGF-β/Smad3 pathway-medicated autophagy and EMT in epithelial ovarian cancer
Research on the impact of the digital economy on carbon emissions based on the dual perspectives of carbon emission reduction and carbon efficiency
Abstract China’s digital economy is currently thriving, with the “dual carbon” targets representing a significant pursuit of economic development. The role of the digital economy in achieving these targets warrants detailed discussion. Using urban panel data from China spanning 2011 to 2021, this paper empirically examines the impact of the digital economy on urban carbon emissions. The findings reveal several key points: Firstly, the digital economy significantly reduces urban carbon emissions and enhances efficiency, a conclusion that remains valid after a series of robustness checks. Secondly, there is a notable structural effect, with different dimensions of the digital economy exhibiting varying impacts on urban emission reduction and efficiency enhancement. Thirdly, green economic efficiency and green technological innovation are crucial mechanisms through which the digital economy facilitates urban carbon emission reduction and efficiency improvement, operating through green development and innovation channels. Fourthly, industrial structure upgrading is a key nonlinear factor reducing the digital economy’s impact on carbon reduction, while the digital economy’s effect on urban carbon efficiency shows a U-shaped pattern. Lastly, the impact of the digital economy on urban carbon emissions displays significant heterogeneity across cities of different locations, tiers, and characteristics.
Dynamic mechanism and evolutionary game analysis of sports industry service transformation
Evaluation of auditory alerting systems for safe electric scooter operations
Abstract It is well understood that a significant shift away from fossil fuel based transportation is necessary to limit the impacts of the climate crisis. Electric micromobility modes, such as electric scooters and electric bikes, have the potential to offer a lower-emission alternative to journeys made with internal combustion engine vehicles, and such modes of transport are becoming increasingly commonplace on our streets. Although offering advantages such as reduced air pollution and greater personal mobility, the widespread approval and uptake of electric micromobility is not without its challenges. Concerns have been raised regarding the safety of such vehicles, most notably related to pedestrian safety of blind and partially sighted individuals, due to the inherently lower sound levels produced by electric vehicles. This study addresses this issue by investigating the use of an Acoustic Vehicle Alerting System (AVAS) for electric scooters by means of a virtual reality experiment and field trials. Eighty-eight participants from four European countries, including thirty-five blind or partially sighted individuals participated across the experiments. Results show high missed detection rates for electric scooter operations without an AVAS in typical city soundscapes (90–97%) and an increase in detectability for all AVAS conditions tested. Modifying AVAS sounds with playback rate and level changes with respect to operational state facilitates detection of deceleration, as well as improving detectability in multiple vehicle scenarios.