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Highly ordered mesoporous iron oxide (α-Fe₂O₃) material has been successfully obtained from mesoporous silica template, KIT-6 (3-D Cubic Ia3d symmetry), through nano-replication method. The mesoporous α-Fe₂O₃ material thus obtained exhibits well-defined mesopores (2.7 nm in diameter), high surface area (148 m²/g), high pore volume (0.47 cm³/g) and crystalline frameworks. The morphology of the mesoporous α-Fe₂O₃ material is very uniform in spherical shape of which the average particle size is about 100 nm in diameter.

A highly efficient method for size reduction of nanoparticles has been reported. Ferroelectric lead zirconate titanate (PZT) particles were used as an example to indicate the working principle. The typical average particle size of PZT particles prepared by hydrothermal method is between 500 and 1000 nm. Through the application of high intensity focused ultrasound (HIFU) to the particles, the average size of the particles is reduced to as small as 10–20 nm. The crystalline structure of the treated particles remains according to the X-ray diffraction (XRD) profiles. Transmission electron microscopy (TEM) shows that the treated particles have identical morphology and size. The nonlinear effects of shock wave introduced by HIFU were studied, and the size reduction results were compared with those by ultrasonic cavitations. Finally, the possible reasons for less damage caused by shock wave were discussed.

NiAl nanosized powders were synthesized by pulsed wire discharge (PWD) using twisted Ni and Al wires with various number of turns (N_t). The X-ray diffraction (XRD) patterns indicated that the optimum conditions for synthesized NiAl nanosized powders were usage of a twisted Ni and Al wire with 0.4 turn/mm discharged in N₂ gas. For clarifying the dependence of N_t on the powder purity, waveforms of current, voltage and deposited energy during the discharges were measured. From the waveforms, deposited energy ratio until a voltage peak (K_p), which is an index to evaluate volume fraction of evaporated wire, was calculated. In low K_p conditions, nanoparticles with low composition ratio of Ni(C_Ni) and large particles with high C_Ni were frequently observed. This result indicated that the Ni wire had a high boiling point than that of Al so that unevaporated Ni remained as large liquid droplets in the discharge. Decrease of K_p was thought that the increase of N_t introduced lattice defects by plastic deformation to increase the resistance and to evaporate the wire partially. From the results above, a method to synthesize NiAl intermetallic compound nanosized powders by PWD was successfully developed using Ni and Al twisted wires. In addition, K_p turned out to be important in synthesizing single-phase nanosized powders.

Carbon nanotubes (CNTs) filled with metals can be used in capacitors, sensors, rechargeable batteries, and so on. Their interface significantly affects the properties of the composites. Here, we show that three kinds of interfaces between crystalline Ni and CNTs exist, namely, ordered, distorted, and disordered. They presented lattice states of Ni atoms near the interface, whereas the (111)_Ni plane was parallel to the CNTs' surface and appeared apart in a smaller or bigger angle. The coherent face-centered cubic (f.c.c)/hexagonal close-packed structure (h.c.p) boundary was formed between the crystalline Ni and CNTs at the ordered interface, in which the match was (111)_Ni//(0001)_Carbon. We suggested a dislocation model for the coherent interface. The model explained why the angle between (200)_Ni and the CNTs' inner surface was 52.9° rather than the theoretical value of 54.75°. The dislocation was formed to fit the coherent relationship. Thus, Ni lattice shrinkage occurred. Further study indicated that the formation mechanism of crystalline Ni in CNTs was through heterogeneous nucleation on the inner wall surface and growth of the crystal nucleus.

The technology of Lithium-ion battery (LIB) separator has become more and more mature. But there are still many problems that needed to be resolved. For example, its mechanical strength is low relatively, thermal stability is bad and the porosity and electrochemical performance are imperfect. This paper introduces modification of electrospinning LIB separator from the way of adding nanoparticles, including SiO₂, TiO₂, Al₂O₃ and copper titanate oxide, etc. And addition methods include dissolving in dispersant, dissolving in polymer solution, coating and in situ method. The modified membranes possess higher ionic conductivity which can reach to the level of 10${}^{-3}$s/cm.

Calcined and dispersible titanium-doped hydroxyapatite (Ti-HAp) nanoparticles at different [Ti/(Ca+Ti)] atomic ratios (0.3, 0.4, and 0.5) were prepared using an anti-sintering method. The Ti substitution ratios of the HAp structures in the feed of Ti-HAp preparation were approximately 80%. Ti-HAp nanoparticles were coated on polyethylene terephthalate (PET) sheets through polyacrylic acid graft-polymers. The PET substrate was almost completely covered with monolayer nanoparticles (over 95%). Antibacterial activity of coated Ti-HAp was calculated from the survival ratio of the bacteria, Staphylococcus aureus, after ultraviolet (UV) irradiation at 312 nm and 6.4 mW/cm² for 30 s. The number of S. aureus on the Ti-HAp coated substrate decreased by 43% compared to those on the original PET and normal HAp coatings as negative controls. The antibacterial activity of Ti-HAp coated substrate was, furthermore, no statistically difference with TiO₂ sheet as a positive control.

Herein, we report that self-assembled surface modification of 4-hydroxy thiophenol and gold nanoparticles imparted trititanate nanotubes (TiNTs) with stable, highly efficient hydrogen production and Photoelectrochemical (PEC) properties. After gold nanoparticles decoration, the modified TiNTs exhibited the photocurrent density of 232 $\mu$A/cm² at 0 V versus Ag/AgCl, with onset potentials ($V_{\mathrm{\text{op}}}$) of −0.4 V versus Ag/AgCl. Our process uses 4-hydroxy thiophenol to achieve control over the bond between gold particles and TiNTs, and improves the distribution uniformity of gold nanoparticles on the surface of TiNTs, which leads to above 90% Faradaic efficiency during 3 h water splitting reaction for hydrogen production.

In this paper, the MHD Jeffery–Hamel flow with cu-water nanofluid between two smooth rectangular walls with the transverse magnetic field is studied. Differential transform method (DTM) is used to obtain the velocity profile of Jeffery–Hamel flow in both convergent and divergent channels for different values of Reynolds number and Hartmann number. Finally, to examine the accuracy and the validity of the method, the obtained results have been compared with the available collation method results.

Stress detection and monitoring have attracted substantial research interests due to stress being a risk factor for health disorders and economic burdens. In particular, the steroid hormone cortisol plays an important role both as an indicator of stress and a coordinator of downstream physiological responses. Recent years have witnessed a flourishing of cortisol biosensors and bioassays based on various physical principles. In this review, we first provide an overview of cortisol function and its presence in different biological matrices. Next, we discuss the existing range of cortisol biosensors, from their sensing principles (i.e. chromogenic, nanoparticle-based colorimetric and fluorometric, surface-enhanced Raman spectroscopy, surface plasma resonance spectroscopy, and electrochemical sensors), performances (sensitivity, selectivity, portability, etc.), and applications. We particularly correlate the sensing performances and their suitability for point-of-care diagnostics with sensor principles and the use of different affinity ligands, such as antibodies, aptamers, molecular imprint, and even 2D materials such as MXenes. Finally, we discuss the challenges and perspectives of future high-performing cortisol sensors for a wider range of applications in human and animal stress monitoring.