High‐Performance Ferroelectric Polymer Side‐Gated CdS Nanowire Ultraviolet Photodetectors

An efficient ferroelectric‐enhanced side‐gated single CdS nanowire (NW) ultraviolet (UV) photodetector at room temperature is demonstrated. With the ultrahigh electrostatic field from polarization of ferroelectric polymer, the depletion of the intrinsic carriers in the CdS NW channel is achieved, which significantly reduces the dark current and increases the sensitivity of the UV photodetector even after the gate voltage is removed. Meanwhile, the low frequency noise current power of the device reaches as low as 4.6 × 10^?28 A² at a source‐drain voltage V_ds = 1 V. The single CdS NW UV photodetector exhibits high photoconductive gain of 8.6 × 10⁵, responsivity of 2.6 × 10⁵ A W^?1, and specific detectivity (D*) of 2.3 × 10¹⁶ Jones at a low power density of 0.01 mW cm^?2 for λ = 375 nm. In addition, the spatially resolved scanning photocurrent mapping across the device shows strong photocurrent signals near the metal contacts. This is promising for the design of a controllable, high‐performance, and low power consumption ultraviolet photodetector.     

XMCD and XMCD‐PEEM Studies on Magnetic‐Field‐Assisted Self‐Assembled 1D Nanochains of Spherical Ferrite Particles

Quasi‐1D nanochains of spherical magnetic ferrite particles with a homogeneous particle size of ≈200 nm and a micrometer‐sized chain length are fabricated via a self‐assembly method under an external magnetic field. This assisting magnetic field (H_assist), applied during synthesis, significantly modifies the distribution of the Fe²⁺O_h, Fe³⁺T_d, and Fe³⁺O_h cations in the chains, as demonstrated by X‐ray magnetic circular dichroism (XMCD) combined with theoretical analysis. This provides direct evidence of the nontrivial role of external synthetic conditions for defining the crystal chemistry of nanoscale ferrites and in turn their magnetic properties, providing an extra degree of freedom for intentional control over the performances of 1D magnetic nanodevices for various applications. Magnetic imaging, performed via XMCD in photoemission electron microscopy, further shows the possibility of creating and trapping a series of adjacent magnetic domain walls in a single chain, suggesting that there is great application potential for these nanochains in 1D magnetic nanodevices, as determined by field‐ or current‐driven domain wall motions. Practical control over the magnetic properties of the nanochains is also achieved by extrinsic dopants of cobalt and zinc, which are observed to occupy the ferrite ionic sites in a selective manner.     

Comprehensive Understanding of the Spatial Configurations of CeO2 in NiO for the Electrocatalytic Oxygen Evolution Reaction: Embedded or Surface‐Loaded

Introducing cerium (Ce) species into electrocatalysts has been recently developed as an effective approach to improve their oxygen evolution reaction (OER) performance. Importantly, the spatial distribution of Ce species in the hosts can determine the availability of Ce species either as additives or as co‐catalysts, which would dictate their different contributions to the enhanced electrocatalytic performance. Herein, the comprehensive investigations on two different catalyst configurations, namely CeO₂‐embedded NiO (Ce‐NiO‐E) and CeO₂‐surface‐loaded NiO (Ce‐NiO‐L), are performed to understand the effect of their specific spatial arrangements on OER characteristics. The Ce‐NiO‐E catalysts exhibit a smaller overpotential of 382 mV for 10 mA cm^?2 and a lower Tafel slope of 118.7 mV dec^?1, demonstrating the benefits of the embedded configuration for OER, as compared with those of Ce‐NiO‐L (426 mV and 131.6 mV dec^?1) and pure NiO (467 mV and 140.7 mV dec^?1), respectively. The improved OER property of Ce‐NiO‐E originates from embedding small‐sized CeO₂ clusters into the host for the larger specific surface area, richer surface defects, higher oxygen adsorption capacity, and better optimized electronic structures of the surface active sites, as compared with Ce‐NiO‐L. Above findings provide a valuable guideline for and insight in designing catalysts with different spatial configurations for enhanced catalytic properties.     

Strain-Controlled Spin Wave Excitation and Gilbert Damping in Flexible Co2FeSi Films Activated by Femtosecond Laser Pulse

The dynamic response of magnetic order to optical excitation at sub-picosecond scale has offered an intriguing alternative for magnetism manipulation. Such ultrafast optical manipulation of magnetism has become a fundamental challenging topic with high implications for future spintronics. Here, this study demonstrates such manipulation in Co₂FeSi films grown on flexible polyimide substrate, and demonstrates how the magneto-optical interaction can be modified by using strain engineering which in turn triggers the excitation of both dipolar and exchange spin waves modes. Furthermore, Gilbert damping and spin-orbit coupling in Co₂FeSi can both be tuned significantly by altering the magnitude and type of applied strain, suggesting an appealing way to manipulate spin wave propagation. These results develop the optical manipulation magnetism into the field of spin wave dynamics, and open a new direction in the application of spin orbitronics and magnonics devices using strain engineering.     

Experimental and calculated effectiveness of a radiochromic dye film to stopping 21 MeV Li and 64 MeV O ions

Relative radiation effectiveness, RE, of 21 MeV ⁷Li and 64 MeV ¹⁶O ions being completely stopped in a tissue equivalent film dose meter has been measured as a function of penetration depth and energy, and the results have been compared with calculations based on a δ-ray theory for heavy charged particles developed by Katz et al. The experiment was designed to test calculations particularly in the Bragg-peak region of the slowing down particles where significant deviation between theory and experiment was found. Fitting of the characteristic D₃₇ dose and the size of the radiation sensitive element in the detector, which are important parameters in the theoretical model, does not improve the overall correlation between theory and experiment. It is concluded that disagreement between theoretical and experimental RE-values below 1.5 MeV/amu is partly due to lack of equivalence between the δ-ray spectrum and the slowing down spectrum of electrons from low-LET radiation, and partly from approximations in the calculated distribution of energy deposition of the δ-rays.     

Histological,transmission electron microscopic,and immunohistochemical study of the adrenal gland in the Persian squirrel (Sciurus anomalus)

This research was aimed to present the histological and ultrastructure properties of the adrenal gland in the Persian squirrel. Two male and female animals were included in the study. The adrenal gland was bean-shaped and located on the cranial pole of kidney. The enveloping capsule was dense connective tissue that reacted positively with Periodic-Acid Schiff (PAS) and Masson trichrome stainings. The parenchyma of the gland consisted of two-part, namely cortex and medulla; the cortex had three layers: zona glomerulosa (ZG), zona fasciculata (ZF), and zona reticularis (ZR). The cells of the ZG were mainly spherical and ovoid with circular arrangement and few lipid droplets in TEM micrographs. The cells of the ZF were columnar and spherical that were arranged in cord-like rows. Transmission electron microscopy (TEM) indicated conspicuous lipid droplets and mitochondria in this zone. The cells of the ZR were arranged in a tangled networks and were almost similar to those in the ZF. TEM images showed fewer lipid vesicles in the ZR compared to the ZF and ZG. Chromaffin cells were located in the medulla of the adrenal gland in two layers. TEM images showed that some of them were smaller and contained fewer secretory granules; other cells were larger and contained more electron-dense secretory granules. Immunofluorescence staining showed that steroidogenic factor 1 (SF1) expressed from cortex to the corticomedullary junction (CMJ) and tyrosine hydroxylase (TH) expressed in the medulla. In conclusion, the results indicated both similarities and differences between the adrenal gland of the Persian squirrel and other animals such as mammals and rodents.     

Formation mechanisms for the dominant kinks with different angles in InP nanowires

The morphologies and microstructures of kinked InP nanowires (NWs) prepared by solid-source chemical vapor deposition method were examined using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Statistical analysis and structural characterization reveal that four different kinds of kinks are dominant in the grown InP NWs with a bending angle of approximately 70°, 90°, 110°, and 170°, respectively. The formation mechanisms of these kinks are discussed. Specifically, the existence of kinks with bending angles of approximately 70° and 110° are mainly attributed to the occurrence of stacking faults and nanotwins in the NWs, which could easily form by the glide of {111} planes, while approximately 90° kinks result from the local amorphorization of InP NWs. Also, approximately 170° kinks are mainly caused by small-angle boundaries, where the insertion of extra atomic planes could make the NWs slightly bent. In addition, multiple kinks with various angles are also observed. Importantly, all these results are beneficial to understand the formation mechanisms of kinks in compound semiconductor NWs, which could guide the design of nanostructured materials, morphologies, microstructures, and/or enhanced mechanical properties.     

Sand-water slurry erosion of carburized AISI 8620 steel

The erosion behavior of carburized AISI 8620 steel for sand slurry service was investigated. The jet impingement type of test was used where sand slurry is directed at flat specimens to determine the erosion rates and mechanism of erosion. The effects of steel heat treatments, slurry velocities and particle concentrations on erosion rates were investigated.     

Single-walled carbon nanotubes induces oxidative stress in rat lung epithelial cells

Single-walled carbon nanotubes (SWCNT) show unique properties find applications in micro devices; electronics to biological systems specially drug delivery and gene therapy. However the manufacture and extensive use of nanotubes raises concern about its safe use and human health. Very few studies have been carried out on toxicity of carbon nanotubes in experimental animals and humans, thus resulted in limiting their use. The extensive toxicological studies using in vitro and in vivo models are necessary and are required to establish safe manufacturing guidelines and also the use of SWCNT. These studies also help the chemists to prepare derivative of SWCNT with less or no toxicity. The present study was undertaken to determine the toxicity exhibited by SWCNT in rat lung epithelial cells as a model system. Lung epithelial cells (LE cells) were cultured with or without SWCNT and reactive oxygen species (ROS) produced were measured by change in fluorescence using dichloro fluorescein (DCF). The results show increased ROS on exposure to SWCNT in a dose and time dependent manner. The decrease in glutathione content suggested the depletion and loss of protective mechanism against ROS in SWCNT treated cells. Use of rotenone, the inhibitor of mitochondrial function have no effect on ROS levels suggested that mitochondria is not involved in SWCNT induced ROS production. Studies carried out on the effect of SWCNT on superoxide dismutase (SOD-1 and SOD-2) levels in LE cells, indicates that these enzyme levels decreased by 24 hours. The increased ROS induced by SWCNT on LE cells decreased by treating the cells with 1 mM of glutathione, N-Acetyl Cysteine, and Vitamin C. These results further prove that SWCNT induces oxidative stress in LE cells and shows loss of antioxidants.