Browse Articles

Investigating the interplay between spin polarization and magnetic damping in CoxFe80−xB20 for magnonics applications

For magnonics and spintronics applications, the spin polarization (P) of a transport current and the magnetic damping (α) play a crucial role, e.g., for magnetization dynamics and magnetization switching applications. In particular, P in a glassy (amorphous) 3d transition ferromagnet such as CoFeB and α are both strongly affected by s−d scattering mechanisms. Hence, a correlation can be expected, which is a priori difficult to predict. In this work, P and α are measured using current-induced Doppler shifts using propagating spin wave spectroscopy and broadband ferromagnetic resonance techniques in blanket films and current-carrying CoxFe80−xB20 alloy microstrips. The measured P ranges from 0.18 ± 0.05 to 0.39 ± 0.05, and α ranges from (4.0 ± 0.2)·10−3 to (9.7 ± 0.6)·10−3. We find that for increasing P, a systematic drop in α is observed, indicating an interplay between magnetic damping and the spin polarization of the transport current, which suggests that interband scattering dominates in CoxFe80−xB20. Our results may guide future experiments, theory, and applications in advancing spintronics and metal magnonics.

Design and implementation of PLA/GO/metal oxide composites for CO2 sensing application

Abstract This study investigates the modification of polylactic acid (PLA) by the incorporation of graphene oxide (GO) and metal oxides (ZnO and CuO), with the aim of developing efficient CO₂ sensors. Key properties, including total dipole moment (TDM), energy gap (ΔE), molecular electrostatic potential (MESP), and density of states (DOS), were calculated using density functional theory (DFT) to gain insight into the interactions between the composites and CO₂ gas. Experimental techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and optical confocal microscopy were used to validate the material composition and bonding mechanisms. The analysis revealed the presence of SiO₂ impurities in the PLA matrix, which could potentially affect the sensing behavior of the composite. The composites demonstrated effective CO₂ sensing capabilities in experimental tests. This combined theoretical and experimental approach demonstrates that PLA/GO/metal oxide composites offer significant potential for sustainable CO₂ sensing, contributing to air quality monitoring and greenhouse gas regulation.

Control of impurity incorporation into CVD diamond synthesized with <i>tert</i>-butylphosphine for quantum applications

Nitrogen-vacancy (NV) centers in phosphorus-doped diamond have potential applications in quantum technologies because their electron spin has the longest spin coherence time among those in solid systems at room temperature (RT) and because their negative charge state is more stable than that in undoped diamond. However, the conventional phosphorus source, phosphine, is toxic and explosive; a safer precursor is therefore preferred. We consequently attempted to synthesize phosphorus-doped diamonds using tert-butylphosphine (TBP), which has lower toxicity and explosivity than phosphine. However, controlling phosphorus incorporation during doping with TBP is difficult because it condenses easily and remains in the synthesis reactor due to its low boiling point. Here, we report controlling the incorporation of impurities by optimizing the synthesis conditions, such as the synthesis pressure. Comparing diamonds synthesized at 15 and 50 kPa reveals that the phosphorus concentration was reduced by 93% and the nitrogen concentration by 72% in the diamond synthesized at 50 kPa. For diamonds prepared under optimized conditions in our synthesis reactor, a long spin coherence time (T2 = 2.23 ms) for NV centers with almost perfect selective alignment of the NV axes was achieved. The T2 was comparable to the longest reported length for NV centers in a sample synthesized with phosphine, indicating that TBP is a promising phosphorus source for obtaining NV centers with excellent properties. We also achieved high electron mobility [580 cm2/(V s) at RT] in diamonds synthesized with TBP; this value is comparable to that for diamonds synthesized with phosphine.

Revealing large-scale surface subsidence in Jincheng City’s mining clusters using MT-InSAR and VMD-SSA-LSTM time series prediction model

Voltage-controlled strain-mediated elliptical micro-magnetic motors for single magnetic bead manipulation

Effective manipulation of magnetic beads (MBs) with dimensions similar to single cells is crucial for advancing clinical and diagnostic technologies. Traditional methods like optical tweezers and dielectrophoresis often require complex setups, making them less suitable for scalable laboratory-on-a-chip (LOC) systems. While strain-mediated magnetoelectric (ME) micro-motors offer a promising alternative, they are limited by a 45° rotation when using planar electrode systems, the complexity of multi-electrode systems for rotations beyond 45°, and the lower thermal stability of symmetrical ferromagnetic (FM) rings or disks. This work introduces a ME-based LOC device that incorporates strain-mediated micro-magnetic motors, utilizing shape-anisotropic FM elliptical rings on a ferroelectric substrate to achieve MB rotations up to 90° experimentally with a simple planar electrode system. The inherent high thermal stability of elliptical FM rings enables this rotation without the need for multi-electrode designs. Micromagnetic simulations are employed to identify the optimal elliptical ring structures that generate the localized stray magnetic fields necessary for trapping and rotating MBs. Effective single MB trapping with optimized MB concentrations and flow rates is demonstrated with 40% capture probability. Under an applied electric field of 0.8 MV/m, a 90o rotation is achieved for a 1.5 μm wide elliptical ring, closely aligning with micromagnetic modeling results. The ability to achieve 90° MB rotation without complicated experimental setup opens possibilities for critical biotechnology applications, such as photothermal and hyperthermia therapy, where the thermally stable, highly shape-anisotropic FMs in ME-based LOC devices could be transformative.

Stacked CNN-based multichannel attention networks for Alzheimer disease detection

Self-reassembly wearable thermoelectric generator using surface-modified TMDCs

Wearable thermoelectric generators (WTEGs) are of significance in the conversion of body heat into electricity for the purpose of powering wearable electronic devices. Two-dimensional (2D) transition metal dichalcogenides (TMDCs) exhibit exceptional thermoelectric power factors and mechanical stability, making them promising flexible thermoelectric materials. However, the output voltage of the present TMDC-based WTEGs remains at a relatively low level. In this study, we precisely modulate the electronic structure of titanium disulfide (TiS2) nanosheets in a restacked film by surface modification, leading to the decoupling phenomenon of a simultaneous rise in the electrical conductivity and the Seebeck coefficient. This method enhances the thermoelectric power factor by approximately 14 times compared to pre-modified samples. We fabricated a flexible self-reassembly WTEG using 1T-phase molybdenum disulfide (MoS2) nanosheets as p-type material and modified TiS2 nanosheets as an n-type material. The generator achieved a voltage output of approximately 15 mV while harvesting heat from the human arm, showcasing its potential for practical applications.

Harnessing 3D microarchitecture of pterosaur bone using multi-scale X-ray CT for aerospace material design

Abstract Pterosaurs were the largest animals to have achieved powered flight in the history of life on Earth, possessing wingspans akin to some modern light aircraft. Vertebrate fossils have shown their potential to retain information on the chemical, physical, and mechanical properties of precursor bone. However, the fossil record is not a traditional source of inspiration for engineers to create palaeo-bioinspired designs. To explore its potential, this study has imaged the three-dimensional porosity of pterosaur bone intending to inspire and improve the mechanical properties of aerospace materials. Historically, two-dimensional histological analysis has resolved fine-scale structures in fossilised bone, which damages the sample. By applying advanced X-ray imaging techniques in this study (using Image Quality Indicators) we show it is possible to non-destructively resolve/verify the microarchitecture of pterosaur bone not previously seen in three dimensions. Pterosaur bone porosity has helped map the macroscopic stresses of this biomaterial but ultimately presents an opportunity to inspire advanced manufactured materials. This microarchitecture of bone offers a unique geometry where self-healing materials with internal monitoring systems can be developed. The iterative process of Darwinian natural selection has evolved multiple engineering solutions that can be reverse engineered to solve challenges facing industry in the 21st Century.

3D protoacoustic radiography: A proof of principle study

We propose protoacoustic radiography (PAR), an imaging modality combining proton excitation and acoustic detection for three-dimensional (3D) imaging from a single proton projection. PAR avoids the effect of multiple Coulomb scattering in imaging by detecting ultrasound. Proton-induced acoustic waves propagate spherically, enabling 3D imaging from a single projection. Additionally, the distinctive feature of proton beams—concentrating energy deposition primarily at the Bragg peak—allows for precise depth-selectivity through proton energy tuning. We performed PAR using clinical proton machines, and our results demonstrate the capability of PAR to reconstruct targets at various depths (between ∼20 and 23 cm) with an axial resolution of 1.3 mm by fully leveraging the Bragg peak and by tuning the kinetic energy of the proton beam. PAR offers opportunities for precise structural determination with protons both in biomedicine and nondestructive testing.

A preliminary investigation of the interaction between expectation and the reflexive allocation of covert spatial attention

A piezoelectric wind-induced vibration energy harvester via the Venturi effect

In this Letter, the Venturi effect is introduced to change the vibration behaviors of a downwind bluff body and a piezoelectric wind-induced vibration energy harvester using the Venturi effect (VE-PWVEH) is reported to offer an alternative solution to enable a high-performance downwind PWVEH. Also, the power generation characteristics were readily adjusted by the flow channel forming the Venturi effect without modifying the PWVEH structure. So, the VE-PWVEH could possess both great power-generating capability at low wind speed and strong robustness at high wind speed. The results demonstrated that both the output voltage and cut-in wind speed were affected by the attack angle of two rectangular plates used for stimulating the constricted channel. There was an optimal attack angle of 60° where a maximum peak voltage of the VE-PWVEH was increased by 621% and the cut-in wind speed was reduced by 171% compared with the harvester without the Venturi effect. Besides, it demonstrated the VE-PWVEH could achieve an output power of 0.863 mW and illuminate about 120 blue LEDs in series. The introduction of the Venturi effect provides a simple and viable method of flow field disturbance to tune the performance of PWVEHs.

Deep convolutional neural network-based enhanced crowd density monitoring for intelligent urban planning on smart cities

Influence of bias-voltage noise on the inelastic cooper-pair tunneling amplifier (ICTA)

We experimentally show that the inelastic cooper-pair tunneling amplifier (ICTA), implementing a DC-powered parametric amplification scheme, can achieve gain and noise performance similar to that of AC-powered Josephson parametric amplifiers. Using experimental data and simulations, we show that the ICTA has near-quantum-limited noise as long as low-frequency voltage noise, expressed as broadening of the Josephson frequency line, is narrower than the amplification bandwidth. We observe a gain of 20 dB across a 11 MHz bandwidth with noise below 1.7 times the quantum limit when the full width at half maximum of the Josephson frequency linewidth is 5.6 MHz.

Nano-scaffold containing functional motif of stromal cell-derived factor 1 enhances neural stem cell behavior and synaptogenesis in traumatic brain injury

Alternating magnetic fields enhanced non-magnetic confined-ruthenium nanoparticles for efficient oxygen evolution reaction

Magnetic heating by alternating magnetic field (AMF) is a fascinating solution to break the bottleneck in oxygen evolution reaction (OER) catalyst improvement. However, practical applications of AMF in electrochemistry are always impeded by the inherent characteristics of the catalyst (i.e., non-magnetic nature and oxidizable feature). Here, a self-heating working electrode substrate of C/Fe3O4/C is proposed to be fabricated, on which non-magnetic Ru nanoparticles confined within the amorphous carbon matrix are deposited as the catalytic layer. Under AMF, magnetic Fe3O4 particle can be stimulated and generate the magnetic heating associated with Néel relaxation, which improves the OER efficiency of Ru nanoparticles with the overpotential at 10 mA cm−2 reduced by 72 mV. Together with the high stability rendered by confined structure, the exploitation of AMF on non-magnetic catalyst is confirmed, and the developed strategy offers a general pathway to advance OER catalyst performance in the future.

Conceptualization of health literacy from the perspective of children and adolescents – a meta-ethnography

First-principles insights into Bi2XO5 (X = Se, Te) monolayers as high-<i>k</i> gate dielectrics for 2D electronics

Scaling silicon-based transistors to sub-ten-nanometer technology nodes presents significant challenges due to the difficult in achieving both atomic-scale thickness and excellent tunneling performance simultaneously. In this work, we employed first-principles calculations to investigate the dielectric properties of two recently reported van der Waals layered materials, Bi2SeO5 and Bi2TeO5. Our results reveal that Bi2SeO5 and Bi2TeO5 monolayers exhibit out-of-plane dielectric constant of 15.2 and 7.6, respectively, with in-plane dielectric constant reaching as high as 39.0 and 26.0. To evaluate their potential as gate dielectrics, we calculated the band offsets and equivalent oxide thicknesses (EOTs) of Bi2SeO5 and Bi2TeO5 monolayers. The results show that both materials exhibit favorable band offsets relative to silicon and transition-metal dichalcogenide channel materials, along with low EOT. Finally, we estimated the dielectric leakage current density utilizing Bi2SeO5 and Bi2TeO5 based on a p-doped silicon-channel transistor, predicting a low leakage current (&amp;lt;10−8 A cm−2). Our study provides theoretical insights into the potential application of bismuth selenite and bismuth tellurite monolayers as gate dielectrics in two-dimensional electronics.

Risk factor analysis of adjacent vertebral compression fracture following the surgery of percutaneous kyphoplasty in postmenopausal women

Emerging properties of the two-dimensional electron gas at LaAlO3/TiO2 heterointerfaces on piezoelectric 0.7PbMg1/3Nb2/3O3–0.3PbTiO3 substrates

Understanding and controlling the emergent electronic transport properties at interfaces of oxides has been a major issue in condensed matter physics for both fundamental science and technological applications. In this work, we report a two-dimensional electron gas (2DEG) formed at the interfaces of amorphous-LaAlO3/TiO2 (a-LAO/TiO2) thin film heterostructures on piezoelectric 0.7PbMg1/3Nb2/3O3–0.3PbTiO3 (PMN–PT) substrates, where the conductive layer is about 2.48 nm. The Kondo behaviors below 50 K are observed depending on TiO2 thickness. In addition, unique negative magnetoresistance (MR) and asymmetry planar angular MR imply the presence of Rashba spin–orbit interactions. Furthermore, the electric-field-controlled hysteresis loop-like resistance changes were obtained in a-LAO/TiO2/PMN–PT heterostructures. A resistance enhancement of ∼8% at room temperature was achieved at an electric field of −1 kV/cm, which indicates that such 2DEG is rather sensitive to the strain in the TiO2 layer. Thus, this work creates a path to exploring the physics of low-dimensional oxide electronics and nonvolatile memory and logic devices.

Investigation of the mechanism of chenodeoxycholic acid in treating acute lung injury through network pharmacology and experimental validation

Abstract Network pharmacology and molecular simulation techniques were employed to predict the potential targets and signaling pathways of chenodeoxycholic acid in the treatment of acute lung injury. Subsequently, its therapeutic effects on acute lung injury were preliminarily validated using animal experiments. The target of Chenodeoxycholic acid in the treatment of acute lung injury was predicted using network pharmacology. Key active ingredients and core targets were further validated using molecular docking studies. Lipopolysaccharide was used to establish a mouse model of acute lung injury to study the effect of chenodeoxycholic acid on acute lung injury. A total of 73 potential targets of Chenodeoxycholic acid for the treatment of acute lung injury were identified, primarily HSP90AA1, STAT3, HSP90AB1, EP300, and NFKB1. These core targets influence pathways associated with bile secretion, prostate cancer, and receptor activation in chemical carcinogenesis. These targets modulate various processes, including steroid metabolism, steroid biosynthesis, and intracellular receptor signaling pathways, thus contributing to the treatment of acute lung injury. Molecular docking results indicated that Chenodeoxycholic acid exhibited strong binding affinity for the core targets, with docking energies ranging from −5.6729 to −7.4138 kcal/mol. The reliability of the results was further verified by molecular dynamics simulations. Results from animal experiments demonstrated that Chenodeoxycholic acid effectively ameliorated pathological injury to lung tissue in mice with acute lung injury, decreased levels of IL-6 and TNF-α (P &lt; 0.01), and increased levels of IL-10 (P &lt; 0.01). The mRNA expression levels of EP300, HSP90AB1, MTOR, and STAT3 were inhibited, while the mRNA expression level of NR1H4 was significantly increased (P &lt; 0.01). Chenodeoxycholic acid can effectively improve acute lung injury.