Nano

Iron oxide-based magnetic nanoparticles (IONPs) have received remarkable attention in a wide range of applications because of their unique physicochemical properties’ inheritance to the nanoscale. Among these nanoparticles (NPs), superparamagnetic iron oxide nanoparticles (SPIONs), as powerful noninvasive NPs, are widely used in nanomedicine applications such as targeted drug/ gene delivery, magnetic separation, cancer therapy, and magnetic resonance imaging (MRI) hyperthermia because of their superparamagnetic activity and remarkable small size. The synthesis of SPIONs and surface modification of these NPs for biological applications is an interesting research topic. These NPs have high magnetic susceptibility, a single magnetic domain, and a controlled magnetic behavior due to the SPION superparamagnetic feature. This review aims to explore the recently developed synthetic routes of SPIONs and show the best parameters to prepare SPIONs using pulsed laser ablation in liquid “PLAL” for biomedical applications. Furthermore, we highlight the properties, coating, and functionalization of SPIONs and their importance for biomedical applications, including targeted drug delivery and cancer therapy.

To improve the electrochemical performance of the supercapacitor, three electrode nanocomposites, NiO, NiS and NiCo₂S₄, have been obtained by simple hydrothermal process and high temperature pyrolysis, and further, the impact of electrolytes of different concentrations on electrochemical performance of supercapacitor has been researched. During the research processing, synergistic effect of Ni, Co and S is considered to enhance the electrical conductivity, and promote electron transfer, ion diffusion and structural stability. The experiment results show that bimetallic sulfides display high electrical conductivity, shorter ion diffusion channels, and faster electron and ion transport rate with the feature of topping electrochemical properties of specific capacity, excellent cycling stability and high rate capability, and besides show that it can improve the electrochemical performance of the material by increasing the concentration of electrolyte. The transition-metal sulfides provide a new promising pathway for the expansion of high-performance electrode materials for supercapacitors.

Thermally induced spin control is one of the main directions for future spin devices. In this study, we synthesized single-phase polycrystalline ErFe${}_{1-x}$Cr_xO₃ and combined the magnetization curves and Mössbauer spectra to determine the macroscopic magnetism at room temperature (RT). The magnetization of the system at various temperatures is well simulated by molecular field theory. And it is found that under the Dzyaloshinskii–Moriya (DM) interaction, not only the B-site ions undergo a reorientation process, but the spins of the A-site ions also change at the same time. The effective spin is defined as the projection of Er${}^{3+}$ on the Fe${}^{3+}$/Cr${}^{3+}$ spin plane, and the whole reorientation process is obtained by fitting. This study will complement the actual process of ErFe${}_{1-x}$Cr_xO₃ spin reorientation and will lay a theoretical foundation for the fabrication of future spin-controlled devices.

With the advent of the aging of the world’s population, the number of patients suffering from Alzheimer’s disease (AD) is increasing year by year, and how to diagnose early and treat AD has become a problem for the world. After decades of hard work, people have made a series of breakthroughs in the pathogenesis of AD. One of the most widely accepted is that there is a large amount of amyloid-$\beta$ protein deposition in the body of AD patients. This also provides us with a new idea for early diagnosis of AD. In this paper, a confined self-assembly system based on AAO/ZnS is constructed to specifically respond to amyloid-$\beta$ protein. The obtained samples were characterized by FESEM, XPS and UV–Vis. This system specifically recognizes A$\beta$ protein by modifying the tryptophan enantiomers. The experimental results show that the samples synthesized under the self-assembly system of modified _D-Trp have higher response sensitivity to amyloid-$\beta$ protein. This provides a new idea for the self-assembly system based on the limited space of the nano-biomimetic channel in biological detection, and also shows great potential in improving the sensitivity of the biodetector.

We report the results of experiments investigating the influence of discharge mode on morphology of Al–Ni bimetallic nanoparticles prepared by underwater electrical explosion (UEE) of intertwined Al/Ni wire. The experiments were conducted using a pulsed power generator with the stored energy of $\sim 18$J (underheat mode) and $\sim 81$J (overheat mode), delivering to the intertwined Al/Ni wire a $\sim 8$kA current rising during $\sim 1\mu$s. By analyzing electrical signals, we conclude that there exists a competitive process between Al wire and Ni wire, and the latter always lags behind the former in various stages, duo to the difference of electrical resistivity. Using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS), the morphology and element composition of nanopowders obtained at underheat mode and overheat mode were studied. The results reveal that core-shell structured Al–Ni nanoparticles can be easily obtained at underheat mode, due to the mismatched specific surface energy and matching lattice type between aluminum and nickel. Besides, the Al–Ni powder prepared by underwater electrical wire explosion (UEWE) has a smaller particle size (less than 100nm) and more consistent particle size distribution compared with traditional preparation methods. These results show that UEWE is very attractive for the preparation of Al–Ni nanopowders, which is helpful in improving the specific surface area of Raney–Ni catalyst.

ZnO has been extensively used as oxide in the thin film electronics industry because of its performance advantages such as electrical and optical properties. This study represents the design and optimization of the ZnO thin film transistor (TFT). The characteristics of the device are studied using the software Silvaco TCAD ATLAS. The improvement in the performance of the device has been observed in optimizing dielectric layer thickness ($T_{\mathrm{\text{ox}}}$). Further SiO₂ oxide layer is replaced with the high-$k$ dielectric to improve its performance. The use of high-$k$ dielectric gives the concept of equivalent oxide thickness (EOT) in which physical thickness (PT) of the dielectric layer is increased without increasing electric thickness (effective thickness), which improves the reliability of the device. The electrical parameters extracted for the low-$k$ SiO2 ($K=3.9$) at thickness (TSiO2) 50nm are $I_{\mathrm{\text{on}}}=2.13\times 10^{-5}$A, $I_{\mathrm{\text{off}}}=1.41\times 10^{-12}$A, $I_{\mathrm{\text{on}}}∕I_{\mathrm{\text{off}}}=10^7$, $\mathrm{\text{SS}}=0.077$V/decade, $\mathrm{\text{VTH}}=0.27$V. The high performance of the device has been achieved using Al₂O₃ and HfO₂ as the dielectric material.

Nanostructure-based resistive switching memory devices are being developed for low power, multilevel storage capability, extended retention capacity, and scalable devices. The zinc tungstate (ZnWO${}_4)$ nanoparticle was prepared via the facile hydrothermal method. The X-ray diffraction technique confirmed ZnWO₄ monoclinic phase and crystallite nature. The scanning electron microscope was used to identify the rod-like ZnWO₄ nanostructure, and further, the lattice orientation was investigated by high-resolution transmission electron microscopy. X-ray photoelectron spectroscopy confirmed the binding states with composition of ZnWO₄. Resistive switching memory based on ZnWO₄ was produced and resulted in low-operating voltage.

Discharging industrial wastewater containing dyes and antibiotics will irreversibly damage the overall environment and human health and prosperity. In this study, magnetic Fe₃O₄ and MoS₂ were loaded on biomass activated carbon (BAC) using co-precipitation and hydrothermal methods, respectively, to obtain MoS₂ functionalized magnetic biomass activated carbon (MoS₂-mBAC), which was used to remove tetracycline hydrochloride (TC) and crystal violet (CV) in wastewater. A series of characterization methods such as SEM, TEM, FT-IR, XRD, VSM and BET were used. The results showed that MoS₂-mBAC has abundant oxygen-containing functional groups, high magnetic properties, large specific surface area (984.05cm²/g), and MoS₂ nanoflowers with a graphene-like structure. Moreover, the whole adsorption process was endothermic, which can be well fitted by pseudo-second-order kinetic and Langmuir model. The maximum adsorption capacity for TC and CV at the optimum pH reached 286.53mg/g and 568.18mg/g. Compared to BAC and mBAC, the adsorption performance of MoS₂-mBAC was greatly improved. After five cycles, the removal rate was still high. MoS₂-mBAC has broad application prospects in wastewater treatment due to its unique advantages, such as wide source, simple process, good performance and high economical availability.