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Energy-dispersive x-ray spectroscopy and high-angle annular dark-field in a Cs-corrected scanning transmission electron microscope are employed to characterize the atomic-scale strain distribution in the active region of the InAs-based interband cascade laser. For the first time, energy-dispersive x-ray spectroscopy is utilized for the quantitative calculation of the zero-strain region, by which the geometric phase analysis of high-angle annular dark-field imaging has been carried out. The strain distribution of the active region with high accuracy has been obtained. The analysis of the out-of-plane strain shows that the active region in the InAs-based interband cascade laser is strain-compensated, while a certain degree of elemental intermixing still exists in the active region. This detailed strain distribution can provide valuable insights into the optimization of the growth conditions for the active region such as growth temperature, V/III flux ratio, and growth process to minimize the elemental intermixing and obtain a better performance interface while maintaining the strain-compensated state. [ABSTRACT FROM AUTHOR]

Over the last two decades, Electron Energy Loss Spectroscopy (EELS) imaging with a scanning transmission electron microscope has emerged as a technique of choice for visualizing complex chemical, electronic, plasmonic, and phononic phenomena in complex materials and structures. The availability of the EELS data necessitates the development of methods to analyze multidimensional data sets with complex spatial and energy structures. Traditionally, the analysis of these data sets has been based on analysis of individual spectra, one at a time, whereas the spatial structure and correlations between individual spatial pixels containing the relevant information of the physics of underpinning processes have generally been ignored and analyzed only via the visualization as 2D maps. Here, we develop a machine learning-based approach and workflows for the analysis of spatial structures in 3D EELS data sets using a combination of dimensionality reduction and multichannel rotationally invariant variational autoencoders. This approach is illustrated for the analysis of both the plasmonic phenomena in a system of nanowires and in the core excitations in functional oxides using low loss and core-loss EELS, respectively. The code developed in this manuscript is open sourced and freely available and provided as a Jupyter notebook for the interested reader. [ABSTRACT FROM AUTHOR]

Low-energy ion beam irradiation, combined with the introduction of impurities, presents a promising approach for nanopatterning silicon (Si) surfaces. In this research, we investigate the surface evolution of Si (100) surfaces irradiated by 75 eV helium (He) plasma, in the presence of tantalum (Ta), traditionally regarded as an impurity incapable of initiating pattern formation, as evidenced in prior studies. The Ta impurities are pre-deposited onto the Si surfaces using the magnetron sputtering method, which offers a more controlled and quantifiable approach compared with the conventional co-deposition route. After irradiation at 800 K, dense cone arrays are produced on the Si surface. The growth of the cones is explored for fluence spanning (1–10) × 1025 m−2. The cross-sectional scanning electron microscope images indicate that the cone lengths and base width are well characterized by t1/2 dependence. The kinetics of the cone growth follow Fick's law, characterized by an effective diffusive mechanism with the coefficients of diffusion: D = 6.49 ± 0.83 × 10−16 m−2 s−1. Transmission electron microscope observations reveal that the cone has distinct inner and outer parts with different microstructures and a clear interface. The growth mechanism of these cones is elucidated as a composite process involving preferential sputtering, the destabilizing influence of He bubbles, and the migration of adatoms. [ABSTRACT FROM AUTHOR]

As a typical toxic substance in environmental water, phenolic pollutants, represented by p-nitrophenol, pose a great threat to the ecological environment. In this study, using WCl6 and oxalic acid as raw materials, a novel p-nitrophenol (PNP) sensor fabricated by tungsten phosphide (WP) nano-particles, has been successfully designed and constructed, which expanded the application of WP nano-materials in the field of electroanalysis. The successful synthesis of WP has been confirmed by a series of characterization techniques such as X-ray diffraction, scanning electron microscope, transmission electron microscope, and X-ray photoelectron spectroscopy. The electrochemical experiments were all carried out in phosphate buffer solution with the pH of 6.5. The WP nano-particles can electrocatalytically oxidize PNP to produce a current for the detection of PNP. The reaction sites of PNP are predicted by Gaussian 09 and Multiwfn. Prominent performance has been recorded for PNP sensor, attaining a wide linear range from 10.00 to 6500.00 μM, a low detection limit of 1.59 μM with the reliable selectivity, repeatability, and stability. Gratifyingly, the prepared sensor could satisfy the requirements of PNP determination in actual environmental water, such as tap water and rainwater. [ABSTRACT FROM AUTHOR]

Appropriate protection and guiding are crucial during peripheral nerves repair. New generation nerve guidance conduits (NGCs) should not only provide mechanical support for the damaged nerve but also support healing processes. One of the most promising tissue regeneration applications is fibrous biomaterials since they are characterized by high porosity, flexibility, and strength. Additionally, they enable cell adhesion and proliferation. In this study, novel fibrous nanocomposites were obtained by applying the electrospinning technique, using polylactic acid (PLA) as a polymeric matrix which was further modified with metallic nanoparticles coated with conductive polymers. Such an approach resulted in the obtainment of biomaterials with a potential ability to conduct nerve impulses. The chemical structure of the obtained composites, as well as the morphology of ready products and separate nanocomponents, were investigated using Fourier-transform infrared spectroscopy (FTIR), transmission electron microscope (TEM) and scanning electron microscope (SEM) techniques. Furthermore, conductive and swelling properties in various media were determined. Finally, biomaterials were confirmed to be non-cytotoxic to L929 mouse fibroblasts and 1321N1 human glial cells. Based on the presented results, it can be concluded that nanofibrous nerve guidance conduits have all the key properties in the process of peripheral nerve regeneration and may constitute an important step in novel NGCs development. [ABSTRACT FROM AUTHOR]

The Guinier–Preston (GP) zones have an important influence on the improvement of the age-hardening level of alloy. We here prepare six kinds of Mg-6Zn-5Al (ZA65) magnesium alloy samples to investigate the microstructural evolution, precipitation behavior, and strengthening mechanism using an optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), and micro-hardness tests. The finding reveals that the GP zones are observed in non-dendritic alloys experiencing pre-aging at 80°C for 24 h, whose formation creates more nucleation sites and accelerate kinetics for precipitated phases. Consequently, the introduced pre-aging has been successful in promoting the increase of the age-hardening level of non-dendritic alloys. The double-aged non-dendritic alloys show a significantly changed microstructure with a high density of long rod-shaped β1′ precipitations, making the age-hardening level of double-aging much better than that of single-aging, and the peak value 90 HV was obtained 4 h in advance, which is an increase of 4 HV compared with that of the direct aged non-dendritic alloy. The strengthening mechanism of non-dendritic alloys is mainly summarized as grain boundary strengthening, GP zone strengthening, and the shearing strengthening of β1′ and β2′ precipitations. Among these, the GP zone strengthening is a fundamental contributor to improving the age-hardening level. [ABSTRACT FROM AUTHOR]

Combining Ceramic and metal phases by explosion treatment is difficult on account of the low toughness and plasticity of the ceramic phases. To solve the problem, fine Yttria-Stabilized Zirconia (YSZ) powders were selected as an example in this work. It can be observed that part of the YSZ powders would agglomerate to spherical large particles spontaneously and YSZ layer can combine with steel substrates strongly after explosion treatment as expected. It can be explained by finite element modeling that YSZ powders were more likely to combine the steel substrate when large and small particles coexisted. Moreover, the interface between YSZ and steel substrates was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). It was found that numerous sharp corners were generated at the interface during explosion process which possessed high resilience, and they improved the bearing capacity of the interface. In microcosm, semi-coherent boundaries and amorphous phases were detected at the interface which led to the strong metallurgical bonding between the two phases. In general, this work offers a feasible method to combine ceramic and metal substrate efficiently in a simple way. [ABSTRACT FROM AUTHOR]

The presence of pharmaceutical pollutants in the environment has become a growing concern due to their persistence and toxic nature. In response to this issue, semiconductor photocatalyst materials have emerged as promising candidates for environmental pollutant removal, particularly under solar light irradiation. In this study, we developed a novel zeolite/Fe3O4/CuS/CuWO4 heterojunction nanocomposite through a simple and facile method. The fabrication process involved a multistep approach wherein Fe3O4, CuS, and CuWO4 were incorporated onto the surface of pure zeolite nanoparticles. X‐ray diffraction, scanning electron microscope, transmission electron microscope, ultraviolet–visible diffuse reflectance spectroscopy, Fourier transform infrared, photoluminescence, and vibrating sample magnetometry were analyzed. The results demonstrated that the zeolite/Fe3O4/CuS/CuWO4 heterojunction nanocomposite exhibited a synergistic integration of excellent properties, indicative of the successful construction of a heterostructure within the nanocomposite. Furthermore, the photocatalytic efficiency of the nanocomposite was evaluated for the degradation of the pharmaceutical pollutant fluoroquinolone levofloxacin (LEVO), and it outperformed individual photocatalysts. Notably, the zeolite/Fe3O4/CuS/CuWO4 nanocomposite achieved an impressive degradation rate of approximately 82.67% of LEVO after 120 min of exposure. Importantly, the synthesized nanocomposite demonstrated excellent reusability, with a photodegradation efficiency of 60.45% after the fifth cycle of LEVO degradation, as there was no significant loss in photocatalytic activity over repeated cycles. Furthermore the highest total organic carbon removal efficiency estimated is 57.43% for heterojunction nanocomposite. These findings highlight the potential of the zeolite/Fe3O4/CuS/CuWO4 heterojunction nanocomposite as an effective, eco‐friendly photocatalyst for pharmaceutical pollutant removal from the environment. [ABSTRACT FROM AUTHOR]

In this paper, the deformation behavior of UNS S32750 (S32750) duplex stainless steel during low cycle fatigue was studied by controlling the number of cycles. The microstructure of the specimens under different cycles was characterized by optical microscope (OM), scanning electron microscope (SEM), electron backscatter diffraction (EBSD), and transmission electron microscope (TEM). The microhardness of the two phases was measured by a digital microhardness instrument. The results showed that the microhardness of ferrite increases significantly after the first 4000 cycles, while the austenite shows a higher strain hardening rate after fatigue fracture, and the microhardness of ferrite and austenite increases by 23 HV and 87 HV, respectively. The two-phase kernel average misorientation (KAM) diagram showed that the continuous accumulation of plastic deformation easily leads to the initiation of cracks inside the austenite and at the phase boundaries. The evolution of dislocation morphology in the two phases was obviously different. With the increase in cycle number, the dislocation in ferrite gradually transforms from dislocation bundles and a dislocation array to a sub-grain structure, while the dislocation in austenite gradually develops from dipole array to an ordered Taylor lattice network structure. [ABSTRACT FROM AUTHOR]

Polar discontinuities occur in oxide heterostructures due to varying net charges in the sub-unit cell layers. These polar discontinuities lead to structural reconstruction and often create diverse functionalities. This work constructs polar discontinuous in La0.67Sr0.33MnO3/SrCuO2 (LSMO/SCO) heterostructures on a (001)-orientated SrTiO3 (STO) substrate under different configurations. By changing the growth order of LSMO and SCO, we found two different compensating mechanisms for polar discontinuity. When LSMO is grown on SCO, interfacial polarity discontinuities result in the generation of a large number of oxygen vacancies within the LSMO film. Thus, the LSMO magnetism deteriorates. For the SCO/LSMO/SCO trilayer, the SCO capping layer can recover the LSMO magnetism. The scanning transmission electron microscope results show an atomic reconstruction at the SCO-on-LSMO interface and several oxygen vacancies at the SrO sublayer. The interface reconfiguration releases the polar energy, thereby inhibiting the generation of oxygen vacancies and improving the ferromagnetism of the LSMO film. Our work studies the impact of polar discontinuity at the interface, providing insights into the effects of interface polar discontinuities on functional materials. [ABSTRACT FROM AUTHOR]

Lately, children's daily consumption of some products, such as cereals and candies, has been rising, which provides a compelling rationale for determining any metallic substances that may be present. Monitoring the concentration of certain metals, like nickel, in these products is necessary due to medical issues in humans when consumed regularly. So, in this work, a novel and highly selective carbon paste as a Ni(II) ion-selective sensor was prepared and investigated using ceramic magnesium aluminum spinel nanoparticles as the ionophore and tritolyl phosphate (TOCP) as a plasticizer. A modified co-precipitation method was used to synthesize the spinel nanoparticles. X-ray diffraction, scanning electron microscope with EDAX, transmission electron microscope, and BET surface area were used to determine the phase composition, microstructure, pores size, particle size, and surface area of the synthesized nanoparticles. The spinel nanoparticle was found to have a nano crystallite size with a cubic crystal system, a particle size ranging from 17.2 to 51.52 nm, mesoporous nature (average pore size = 8.72 nm), and a large surface area (61.75 m2/g). The composition ratio of graphite carbon as a base: TOCP as binder: spinal as ionophore was 67.3:30.0:2.7 (wt%) based on potentiometric detections over concentrations from 5.0 × 10−8 to 1.0 × 10−2 mol L−1 with LOD of 5.0 × 10−8 mol L−1. A measurement of 29.22 ± 0.12 mV decade−1 over pH 2.0–7.0 was made for the Nernstian slope. This sensor demonstrated good repeatability over nine weeks and a rapid response of 8 s. A good selectivity was shown for Ni(II) ions across many interferents, tri-, di-, and monovalent cations. The Ni(II) content in spiked real samples, including cocaine, sweets, coca, chocolate, carbonated drinks, cereals, and packages, were measured. The results obtained indicated no significant difference between the proposed potentiometric method and the officially reported ICP method according to the F- and t-test data. In addition to utilizing ANOVA statistical analysis, validation procedures have been implemented, and the results exceed the ICP-MS methodology. [ABSTRACT FROM AUTHOR]

Previous studies on the austenite grain growth were mostly based on a fixed temperature, and the relationship between the austenite grain and austenitizing parameters was fitted according to the results. However, there is a lack of quantitative research on the austenite grain growth during the heating process. In the present work, based on the diffusion principle of the controlled Ti microalloying element, the diffusion process of carbonitrides containing Ti during the heating process was analyzed. Combined with the precipitation model and the austenite growth model, the prediction model of austenite grain growth of Ti microalloyed steel during different heat treatment processes was established. The austenite grain size versus the temperature at four different heating rates of 0.5, 1, 10, 100 °C/s was calculated. The grain growth behavior of austenite during the heating process of Ti microalloyed steel was studied by optical microscope, scanning electron microscope and transmission electron microscope. The experimental data of the austenite grain size was in good agreement with the calculation by the proposed model, which provides a new idea for the prediction of austenite grain size in non-equilibrium state during the heating process. In addition, for Ti-containing microalloyed steels, the austenite grain size increased with the increasing heating temperature, while it changed little by further prolonging isothermal time after certain heating time, which was related to the equilibrium degree of the precipitation and the dissolution of Ti element. The austenite grain coarsening temperature of the tested Ti microalloyed steel was estimated within 1100~1200 °C. [ABSTRACT FROM AUTHOR]

Ni 1-x Ag x O nanoparticles (NPs) with x = 0.00, 0.02, 0.04, 0.06, and 0.08) were fabricated using the composite hydroxide mediated (CHM) method. The effects of Ag doping on the structural, magnetic, and antimicrobial characteristics of NiO NPs have been reported. The stretching mode of the Ni–O molecules was identified at 443 cm−1 in the Fourier transform infrared spectra. The aggregation of nanoparticles with different sizes and shapes is seen under transmission and scanning electron microscopes. The blocking temperature (T B) peak in zero-field cooled (ZFC) magnetization curves display the magnetization from the core of NPs. This peak is absent for the samples with x = 0.00 and 0.02 , which show instead a small net magnetization from the antiferromagnetic core of these NPs. However, a T B peak was found for the samples with x = 0.04 , 0.06 and 0.08 , at 22, 72, and 65 K, respectively, which indicates that the magnetization is induced from the AFM core of NiO NPs for higher Ag doping. With an increasing concentration of Ag in the NiO NPs, the net magnetization did increase and a maximum was found for x = 0.04 at 300 K. For a higher doping concentration of 8 % Ag, a sharp decrease in magnetization was observed. Furthermore, the efficacy and synergistic effect of Ag doping had been analyzed for the effective improvement of the antibacterial properties of NiO NPs. Pure and Ag-doped NiO NPs were exploited to assess their anti-microbial activity against Enterobacter sp., E. coli, P. aeruginosa, and S. pyrogens. The study revealed that anti-bacterial or anti-biofouling properties were introduced as an additional attribute to NiO NPs by incorporation of Ag ions due to its inherent nature as an antimicrobial agent and enhanced its capability to sterilize microbial pathogens. [ABSTRACT FROM AUTHOR]

Heavy metal poisoning is the most prevalent health hazard at hazardous waste sites, affecting a large population on daily basis, with arsenite poisoning ranking third in terms of prevalence and severity. Therefore, the main objective of this study is to develop a novel, highly efficient sensor for detecting trace amounts of arsenite (AsIII) in human serum by utilising reduced graphene oxide/gold nanoparticles (rGO/AuNPs) based nanocomposite structure. In this work, a screen-printed carbon electrode (SPE) was modified using rGO/AuNPs nanocomposite to detect AsIII in human serum. The detection data were recorded and analysed using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV), whereas transmission electron microscope (TEM), scanning electron microscope (SEM) as well as Fourier transform infrared (FTIR) spectroscopy were used to determine the surface morphological features and the presence of significant elements/groups in the prepared nanocomposite structure. Under the optimised conditions, the linear regression coefficient (R2) for the DPV response of the fabricated electrode (rGO/AuNPs@SPE) was observed to be 0.98. The rGO/AuNPs@SPE demonstrated remarkable sensor response for AsIII with detection limits of 10 ppb via DPV in standard samples, due to the synergistic effect of rGO and AuNPs based nanocomposite. The sensitivity of the sensor was found to be 0.0142 Appb−1cm−2 for 100–1000 ppb concentration range of AsIII. The rGO/AuNPs@SPE sensor also displayed good stability and reproducibility when used in AsIII spiked human serum samples in which the limit of detection was observed at 100ppb. The porous structure of rGO on the sensing interface efficiently improves the electrode's adsorption and conductivity, while citrate capped AuNPs offer the functional groups required for maximum adsorption of AsIII. Hence, the developed electrochemical sensor (rGO/AuNPs@SPE) can be used very precisely and reliably in various applications for trace level detection of AsIII in human serum. [ABSTRACT FROM AUTHOR]

[Display omitted] Single-atom catalysts (SACs) have received much attention in the realm of energy and catalytic conversion due to their maximum atomic efficiency. Herein, we report a cascade anchoring strategy for the preparation of a Cu-S 1 O 2 species of single-atom catalyst attached to a carbon carrier containing P and S (Cu-S 1 O 2 SA/CPS) with a content of 12.4 wt%. Over the Cu-S 1 O 2 SA/CPS catalyst, the conversion of 95.8% and selectivity of 87.2% for acetylene hydration could still be achieved at 70 h (T = 200°C, GHSV(C 2 H 2) = 90 h−1 and V H2O /V C2H2 = 4). X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) tests reveal that the Cu atoms of Cu-S 1 O 2 SA/CPS are predominantly coordinated in a trinary manner (Cu-S 1 O 2). Based on high-resolution aberration-corrected high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM), it is demonstrated that the Cu single-atom sites are highly dispersed in Cu-S 1 O 2 SA/CPS. It is evident from the scanning electron microscopy (SEM) that Cu-S 1 O 2 SA/CPS has a two-dimensional layered structure. The specific structure of the active site Cu is primarily attributed to the coordination of S and O atoms, resulting in its superior stability for acetylene hydration towards the synthesis of acetaldehyde. Density functional theory (DFT) calculations confirm that the formation of the Cu-S 1 O 2 site facilitates the activation of acetylene, which is a pivotal step in the acetylene hydration process and considered as the rate-determining step. This article not only introduces an innovative strategy in the synthesis of Cu SACs but also represents a significant breakthrough in the stability of Cu SACs in acetylene hydration. [ABSTRACT FROM AUTHOR]

The gadolinium vanadate doped with samarium (GdVO4:Sm3+) nanopowder was prepared by the solution combustion synthesis (SCS) method. After synthesis, in order to achieve full crystallinity, the material was annealed in air atmosphere at 900 °C. Phase identification in the post-annealed powder samples was performed by X-ray diffraction, and morphology was investigated by high-resolution scanning electron microscope (SEM) and transmission electron microscope (TEM). Photoluminescence characterization of emission spectrum and time resolved analysis was performed using tunable laser optical parametric oscillator excitation and streak camera. In addition to samarium emission bands, a weak broad luminescence emission band of host VO43− was also observed by the detection system. In our earlier work, we analyzed the possibility of using the host luminescence for two-color temperature sensing, improving the method by introducing the temporal dependence in line intensity ratio measurements. Here, we showed that further improvements are possible by using the machine learning approach. To facilitate the initial data assessment, we incorporated Principal Component Analysis (PCA), t-Distributed Stochastic Neighbor Embedding (t-SNE) and Uniform Manifold Approximation and Projection (UMAP) clustering of GdVO4:Sm3+ spectra at various temperatures. Good predictions of temperature were obtained using deep neural networks. Performance of the deep learning network was enhanced by data augmentation technique. [ABSTRACT FROM AUTHOR]

Alternative fuel sources are necessary in today's economic and environmental climate. Hydrogen fuel arises as an environmentally friendly and energy dense option; however, the volatility of hydrogen gas makes it dangerous to store and utilize. The evolution of hydrogen from hydrogen feedstock materials may prove to overcome this safety barrier, but a catalyst for this reaction is necessary to optimize production. In this work, a composite catalyst comprised of palladium nanoparticles embedded on mesoporous carbon materials (Pd-MCM) was synthesized and characterized by Transmission Electron Microscope (TEM), Powder X-Ray diffraction (P-XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectroscope (EDS). Various reaction conditions such as concentration of reactant, temperature, and pH were applied in measuring the catalytic activity of Pd-MCM. Results show the catalytic activity of the Pd-MCM composite catalysts increased with increasing concentrations of sodium borohydride, increasing temperature, and lower pH. The reaction involving the Pd-MCM composite had an activation energy of 27.9 kJ mol−1. Reusability trials showed the Pd-MCM composite remained stable for up to five consecutive trials. [ABSTRACT FROM AUTHOR]

AbstractTo improve the corrosion resistance of 304SS, a polyvinyl butyral/organic montmorillonite-chitosan (PVB/OMMT-Ch) composite coating was prepared by the spin coating method. The Montmorillonite was organically modified with Cetyltrimethylammonium Bromide and compounded with Chitosan to obtain OMMT-Ch. OMMT-Ch filler has been introduced into the polyvinyl butyral coating to improve the corrosion resistance of 304 stainless steel. Scanning electron microscope and transmission electron microscope observations showed that the introduction of chitosan made the montmorillonite layers rounded and loose, and the X-ray diffraction (XRD) results indicated that the interlayer spacing between the montmorillonite layers changed significantly, and the FT-IR results of the chitosan/montmorillonite insertion complexes were in good agreement with those of the XRD analyses, which showed that chitosan successfully inserted between the layers of montmorillonite. The corrosion resistance of the composite coatings in 3.5% NaCl solution was tested by Tafel polarization curves and electrochemical impedance spectroscopy. The results showed that the composite coatings doped with 0.5% OMMT-Ch had the best corrosion resistance with long-lasting protection of more than 160 days. This study suggests a novel approach for nanocomposites for dealing with the 304SS corrosion issue. [ABSTRACT FROM AUTHOR]

In this paper, the microstructure and mechanical properties of Al-6.5Si-5.5Cu-0.2Zr-0.01Sr-0.06Ti-0.2Ce cast aluminum alloys were investigated in multistage solid solution systems. The microstructure of the alloy was characterized using an optical microscope (OM), scanning electron microscope (SEM), energy-dispersive spectrometer (EDS), x-ray diffraction (XRD) and transmission electron microscope (TEM), respectively. The hardness and conductivity of the alloy were measured using a Vickers hardness and eddy current conductivity testers, respectively, and the tensile properties were described by a drawing machine. The results showed that the mechanical properties of the alloy are the worst under the four-stage solid solution system (G1). With the increase in multistage solution temperature and holding time, θ phase (Al2Cu) was gradually dissolved into α-Al matrix to enhance the effect of dislocation strengthening. When the solution temperature reached 510 °C, the mechanical properties of the alloy were the best, and the tensile strength and elongation were increased to 354.90 MPa and 9.02%, respectively. With the increase in temperature, eutectic Si agglomeration and large area of insoluble phase between metals were found, resulting in the decrease in mechanical properties. [ABSTRACT FROM AUTHOR]

A 700 V pulsed laser was used for the surface treatment of Zircaloy-4. Phases including the treatment layer, morphology and the distributions of alloying elements of the treatment layer were detected via X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the laser surface treatment (LST) layer is also α-Zr phase layer, the morphology of the treatment layer was "cauliflower-like" and the Fe-Cr precipitates in the LST layer were dissolved. The corrosion tests of the LST and the no-laser surface treatment (NLST) specimens were conducted in steam at 1100 °C using TGA (NETZSCH STA 449 F). The results showed that LST can enhance the corrosion resistance of the Zircaloy-4 in high-temperature steam. More microcracks distributed in the oxide film formed on the NLST specimen than on the LST specimen. And the volume fraction of the tetragonal zirconia (t-ZrO2) phase in the oxide film on the surface of the LST specimen was higher than that of NLST specimen. The main reason for this phenomena could be attributed to the dissolving Fe-Cr precipitates and higher solid solution of Fe and Cr in the laser treatment layer. [ABSTRACT FROM AUTHOR]

In this work, 2D ferromagnetic M3GeTe2 (MGT, M = Ni/Fe) nanosheets with rich atomic Te vacancies (2D‐MGTv) are demonstrated as efficient OER electrocatalyst via a general mechanical exfoliation strategy. X‐ray absorption spectra (XAS) and scanning transmission electron microscope (STEM) results validate the dominant presence of metal‐O moieties and rich Te vacancies, respectively. The formed Te vacancies are active for the adsorption of OH* and O* species while the metal‐O moieties promote the O* and OOH* adsorption, contributing synergistically to the faster oxygen evolution kinetics. Consequently, 2D‐Ni3GeTe2v exhibits superior OER activity with only 370 mV overpotential to reach the current density of 100 mA cm−2 and turnover frequency (TOF) value of 101.6 s−1 at the overpotential of 200 mV in alkaline media. Furthermore, a 2D‐Ni3GeTe2v‐based anion‐exchange membrane (AEM) water electrolysis cell (1 cm2) delivers a current density of 1.02 and 1.32 A cm−2 at the voltage of 3 V feeding with 0.1 and 1 m KOH solution, respectively. The demonstrated metal‐O coordination with abundant atomic vacancies for ferromagnetic M3GeTe2 and the easily extended preparation strategy would enlighten the rational design and fabrication of other ferromagnetic materials for wider electrocatalytic applications. [ABSTRACT FROM AUTHOR]

In this work, the precipitation behavior and recrystallization behavior of highly alloyed Al-Zn-Mg-Cu alloy with different Zn/Mg ratio were investigated using optical microscope, scanning electron microscope, X-ray diffraction, transmission electron microscope and tensile test. The results indicated that the primary phase increases with Zn/Mg ratio dropping, which increases the nucleation particles and refines the grains. The real solidification path is between Lever law and Scheil model, which is closer to Scheil model. The precipitates are η′ when Zn/Mg ≥ 4.19 in T6 temper. However, it is the co-precipitation of η' and T' when Zn/Mg < 4.19 and the fraction of η' decreases from 100 to 7.6% as Zn/Mg ratio decrease from 4.19 to 1.91. In addition, the impact of residual eutectic phase in a low Zn/Mg ratio alloy on recrystallization behavior and mechanical properties was discussed. Grain boundary primary phases in low Zn/Mg alloys are difficult to completely dissolve during the solid solution. Interestingly, the particle stimulated nucleation occurs preferentially around the second phase and gradually extends to the center of the grain, and there are still low angle grain boundaries in the center of larger original grain. When Zn/Mg > 1.91, the tensile strength increases with Zn/Mg ratio dropping. After Zn/Mg ≤ 1.91, the tensile strength decreases slightly due to the residual second phase. [ABSTRACT FROM AUTHOR]

The present research focuses on the effects of different processing routes on the physical and mechanical properties of nano Ti(CN)-based cermets with metallic binders. Tungsten carbide (WC) is added as a secondary carbide and Ni-Co is added as a metallic binder to nano Ti(CN)-based cermet processed via conventional and spark plasma sintering (SPS). A systematic comparison of the composition and sintering conditions for different cermets' systems was carried out to design novel composition and sintering conditions. Nano TiCN powder was prepared by 30 h of ball milling. The highest density of >98.5% was achieved for the SPS-processed cermets sintered at 1200 °C and 1250 °C for 3 min at 60 MPa of pressure in comparison to the conventionally sintered cermets at 1400 °C for 1 h with a two-stage compaction process—uniaxially at 150 MPa and isostatically at 300 MPa of pressure. Comparative X-ray diffraction (XRD) analysis of the milled powders at different time intervals was performed to understand the characteristics of the as-received and milled powders. Peak broadening was observed after 5 h of ball milling, and it increased to 30 hr. Also, peak broadening and a refined carbide size was observed in the XRD and scanning electron microscope (SEM) micrographs of the SPS-processed cermet. Transmission electron microscope (TEM) analysis of the milled powder showed that its internal structure had a regular periodic arrangement of planes. SEM base scattered electron (BSE) images of all the cermets primarily showed three major microstructural phases of the core–rim–binder with black, grey, and white contrast, respectively. With the present sintering conditions, a high hardness of ~16 GPa and a fracture toughness of ~9 MPa m1/2 were obtained for SPS-processed cermets sintered at higher temperatures. [ABSTRACT FROM AUTHOR]

Riboflavin (RF) or vitamin B2 is susceptible to photodegradation. Encapsulation of sensitive components by modified yeast cells is a promising method for their widespread usage at industrial scale. Saccharomyces cerevisiae has been introduced as an appropriate carrier of bioactive compounds. The yeast cell comprises a phospholipid membrane that protects the core from the external environment. In this study, the effect of plasmolysis on efficiency of S. cerevisiae cells in encapsulation of RF were investigated. According to the results, plasmolysis increased the encapsulation efficiency (53.85% versus 58.22% for non-plasmolyzed and plasmolyzed yeast cells, respectively) and loading capacity (14.10 and 16.99% for non-plasmolyzed and plasmolyzed yeast cells, respectively). The loaded intact cells had a tied and intertwined structure while the loaded plasmolyzed cells were seen separately in the Scanning Electron Microscope images. According to the Transmission Electron Microscope images, plasmolysis did not destruct the yeast cells and the cell integrity was retained appropriately after the process but it increased the internal space for encapsulation. In X-ray diffraction analysis, RF had a crystalline structure and its encapsulation within the amorphous non-plasmolyzed and plasmolyzed yeast cells led to slight crystallinity in the structure of complex. The observed spectra of functional groups in Fourier Transform Infrared spectroscopy confirmed the successful entrapment of RF in the yeast cells. Plasmolysis depleted the cell contents susceptible to thermal process through which melting point of the yeast cells increased. Owing to the charged surface of yeast cells, they showed a burst release of RF in the simulated stomach (88% for non-plasmolyzed and 84% for plasmolyzed cells) and intestinal fluid (91% and 96% for non-plasmolyzed and plasmolyzed cells, respectively). [ABSTRACT FROM AUTHOR]

Strain engineering is an alternative to chemical modification in manipulating functionalities of materials. Here, we report the lattice strain could relax the abrupt phase transition of (Ni1−xFex)1−δS and lead to an excellent negative thermal expansion (NTE) effect. The high-resolution scanning transmission electron microscope and extended x-ray absorption fine structure unambiguously demonstrate that parallel Ni3S4-type nanosheets could be introduced into the matrix lattice by increasing the δ value. By forming the Ni(Fe)-S-Ni(Fe) bonds, the (1–11) plane of nanosheets epitaxially grows on the (002) plane of the hexagonal matrix. Those bonds are strong enough to bear the large lattice mismatch along the interface as the phase transition occurs. As the concentration of nanosheets increases, the weak and inhomogeneous strain in matrix lattice becomes strong and uniform, expanding the NTE window in different ways. This result opens an unconventional avenue for designing NTE materials and extends the research scope of lattice strain as well. [ABSTRACT FROM AUTHOR]

The significant impact of Nb on ferrite transformation, both in terms of solute drag effect (SDE) and interphase precipitation, was investigated quantitatively. Ferrite transformation kinetics were characterized using thermal expansion experiments and theoretical calculations. The microstructures were characterized using high−temperature confocal laser scanning microscopy (CLSM), a field−emission scanning electron microscope (FESEM), and a transmission electron microscope (TEM). Under a higher driving force, interphase precipitations were observed in the sample with a higher Nb content. A three−dimensional (3D) reconstruction method was used to convert the two−dimensional (2D) image of interphase precipitation into a three−dimensional model for a more typical view. The SDE and interphase precipitation had opposite effects on the kinetics of ferrite transformation. A lower Nb content showed a strong contribution to the SDE, which delayed ferrite transformation. A higher concentration of Nb was expected to enhance the SDE, but the inhibition effect was eliminated by the interphase precipitation of NbC during interfacial migration. Both the experimental results and theoretical calculations confirmed this phenomenon. [ABSTRACT FROM AUTHOR]

A nanostructure of lithium-zinc copper ferrite (LiZnCu-Ferrite) prepared experimentally by the auto-combustion method depends on different parameters. The auto-combustion method operates at a temperature (160 °C) suitable for preparing the required nanostructure ferrite phase. The dependent composition was [Li 0.5-x Zn x Cu x Fe 2.5-x O 4 at (x = 0, 0.05, 0.15, 0.25, 0.35, and 0.45)]. A pre-firing at temperature (650 °C) was applied during the calcination process that was suitable to remove unwanted products. The sintering at temperature (800 °C) was suitable for a pelletized shape of ferrite samples. The X-ray diffraction (XRD) pattern showed a spinel structure of ferrite phase produced for all samples under study with the lattice constant in the range (8.345–8.368 Å) as a function of (x). The crystallite size was in the range (18.41–30.27 nm) calculated by the Scherrer method. The transmission electron microscope (TEM) showed a production of nanorods in the size range (10–45 nm) and nanoparticles in the size range (10–40 nm). There was a coincidence between the results of the XRD and TEM analyses. On the other hand, the scanning electron microscope (SEM) showed the surface morphology and the nature of grain size, which was a sign of the presence of nanostructure; it agreed with the XRD analysis. FTIR spectra showed evidence that the system Li0.5-xZnxCuxFe2.5-xO4 had spinal ferrite nanoparticles successfully prepared by sol-gel auto-combustion. A vibrating sample magnetometer (VSM) showed a change in magnetic parameters as compensation factor (x) increased for all composites of LiZnCu-ferrite such as saturation magnetization (Ms), initial magnetic permeability (μi), remanence (Mr), and coercive force (Hc) that measured from M − H loops. A saturation magnetization increased as a function of (x) and recorded a maximum value at (x = 0.15). While the coercivity, initial magnetic permeability (μi), and remanence magnetization enhanced as a function of (x) and recorded a maximum value at (x = 0.45). [ABSTRACT FROM AUTHOR]

In this paper, the solid-state shear milling (S3M) strategy featuring a very strong three-dimensional shear stress field was adopted to prepare the high-performance polyoxymethylene (POM)/molybdenum disulfide (MoS2) functional nanocomposite. The transmission electron microscope and Raman measurement results confirmed that the bulk MoS2 particle was successfully exfoliated into few-layer MoS2 nanoplatelets by the above simple S3M physical method. The polarized optical microscope (PLM) observation indicated the pan-milled nanoscale MoS2 particles presented a better dispersion performance in the POM matrix. The results of the tribological test indicated that the incorporation of MoS2 could substantially improve the wear resistance performance of POM. Moreover, the pan-milled exfoliated MoS2 nanosheets could further substantially decrease the friction coefficient of POM. Scanning electron microscope observations on the worn scar revealed the tribological mechanism of the POM/MoS2 nanocomposite prepared by solid-state shear milling. The tensile test results showed that the pan-milled POM/MoS2 nanocomposite has much higher elongation at break than the conventionally melt-compounded material. The solid-state shear milling strategy shows a promising prospect in the preparation of functional nanocomposite with excellent comprehensive performance at a large scale. [ABSTRACT FROM AUTHOR]

Lithium-doped anatase-TiO2 nanoparticles (LixTi1-xO2 NPs, x = 0, 0.05, 0.10, 0.15 and 0.20) could be synthesized by a simple sol–gel process. X-ray diffraction (XRD) results displayed the tetragonal (space group: I41/amd) of polycrystalline TiO2 anatase phase. The spectroscopy results of Raman and FT-IR confirmed the anatase phase of TiO2 through the specific modes of metal oxides vibration in the crystalline TiO2. Surfaces micrographs by scanning electron microscope (SEM) of agglomerated LixTi1-xO2 NPs showed a spongy like morphology. Transmission electron microscope (TEM) illustrated a cuboidal shape of dispersed NPs with particle size distributed in a narrow range 5–10 nm. Bruanauer Emmett-Teller (BET) results showed the increased surface area of LixTi1−xO2 NPs with increasing Li content. LixTi1-xO2 NPs (x = 0.05–0.20) working electrodes illustrated a pseudocapacitive behavior with excellent electrochemical properties through the whole cycles of GCD test. Interestingly, Li0.1Ti0.9O2 NPs electrode illustrated a high performance in terms of maximum specific capacitance 822 F g−1 at 1.5 A g−1 in 0.5 M Li2SO4 electrolyte, with excellent capacitive retention 92.6% after 5000 cycles GCD test. [ABSTRACT FROM AUTHOR]

Corundum and transition alumina powders are commonly produced through the Bayer process—that is, by digestion of bauxite in a sodium hydroxide solution, followed by gibbsite precipitation, which contains significant amounts of Na+ ions. During the de‐hydroxylation of gibbsite, Na+ is associated with retardation of the structural phase transformations between transition alumina and corundum (α‐Al2O3) phases, although the exact role of Na is unclear. The influence of Na+ ions on the phase transformation of γ‐Al2O3 to α‐alumina was investigated by varying the concentration of NaOH in aqueous γ‐Al2O3 suspensions. The phase transformation behavior of γ‐Al2O3 was monitored through thermal analysis, X‐ray diffraction, scanning electron microscope, X‐ray photoelectron spectrometer (XPS), and transmission electron microscope. As the Na concentration in γ‐alumina suspensions increased, the amount of α‐Al2O3 decreased in samples that were heat treated at 1200°C for 2 h. XPS analysis indicated that washing transition alumina powders with NH4OH solutions had decreased the surface concentration of Na+ and facilitated the phase transformation to α‐Al2O3. [ABSTRACT FROM AUTHOR]

Multi-walled carbon nanotubes (MWCNTs) have significant environmental concerns for soil, water and ecosystems. Since their harmful effects on human health, including respiratory disease, they are considered dangerous substances. Thus, it is required to discover a constructive solution to decrease of MWCNT toxicity. Due to their high degradability, white rot and soft rot fungi have been used in the biodegradation of various pollutants. In this study, we evaluated the ability of native Iranian white and soft rot fungi to degrade MWCNTs mainly by means of dynamic light scattering (DLS) and surface charge measurement. In this regard, growth kinetics, CO2 and protein production, size, surface charge and pH change were measured. Continuous Raman spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM) imaging were carried out to detect the process of degradation. The results showed that the morphology, arrangement, size and diameter of MWCNTs were modified due to fungal degradation. The cytotoxicity of treated MWCNTs was determined by the MTT test. The results indicated that native Iranian white and soft rot fungi have a significant ability for degradation of MWCNTs. Furthermore, it could be concluded that fungal treatment could reduce the toxicity of MWCNTs and the best result was achieved in 500 ppm MWCNTs for Trichoderma sp. The activities of oxidative enzymes such as laccase, manganese peroxidase (MnP) and lignin peroxidase (LiP) were measured to determine the mechanism of degradation. Enzyme assays have suggested that these oxidising enzymes especially laccase might play a key role in the degradation of MWCNTs in white rot and soft rot fungi. The overall results confirmed the reproductive ability of Trichoderma sp. WF29 as a soft rot and two white rot fungi Irpex lacteus WF36 and Trametes versicolor to degrade MWCNT. [ABSTRACT FROM AUTHOR]

In order to study the effect of the preparation process on the microstructure and mechanical properties of metal hollow sphere composites (MHSCs), they were fabricated using different preparation processes (different holding times) by a pressure casting method. The physical parameters of the MHSCs were measured using a direct measurement method, and the phases and microstructure of the MHSCs were observed using an X-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and transmission electron microscope (TEM). Moreover, the mechanical properties of MHSCs were analyzed by a Zwick/Roell Z2.5 microhardness tester and a universal testing machine. The microscopic morphology and composition analysis results showed that the microstructures of MHSCs varied by holding time, while the mechanical properties test results implied that the microhardness of the transition layer and the matrix increased with the extension of the holding time. However, the MHSCs held for 10 min exhibited the best compression performance. These observations indicated that the compressive properties of MHSCs were mainly dependent on the transition layer and the matrix, excluding the influence of metal hollow spheres, and that the transition layer had a significant impact on the compression performance of MHSCs. [ABSTRACT FROM AUTHOR]

In order to improve the pseudocapacitance performance of metal sulfide electrode materials and obtain supercapacitor energy storage devices with excellent electrochemical reversibility and long-term cycle stability, the synthesis of flower-shaped crystal nickel–cobalt sulfide and its supercapacitor performance were studied. NiCo2S4 flower-shaped crystal nickel–cobalt sulfide was prepared by the hydrothermal method with nickel foam as the raw material, and electrode materials were added to prepare supercapacitor electrodes for testing of the supercapacitor performance. The physical properties of flower-shaped crystal nickel–cobalt sulfide were tested by a scanning electron microscope and transmission electron microscope, and the voltammetric cycle and constant current charge and discharge of supercapacitor electrodes prepared from this sulfide were analyzed through experiments. The experimental results showed that the flower crystal microstructure had a positive effect on the electrochemical properties. The capacitance value was always high at different current densities, and the capacity was as high as 3867.8 A/g at pH 12. After 2000 voltage–charge–discharge cycle tests, the petal-like sulfide capacity still had a retention rate of 90.57, the flower crystal nickel–cobalt sulfide still showed an excellent supercapacitor performance and the specific capacity was still high, which demonstrates that this sulfide has excellent cyclic stability and durability in electrochemical applications. [ABSTRACT FROM AUTHOR]

Electrocatalytic n-valeraldehyde oxidation reaction was an inexpensive and eco-friendly method to control n-valeraldehyde contamination and produce high value-added octane. However, low-cost and readily available electrocatalysts with high current efficiency were urgently needed. Herein, two-dimensional porous carbon derived from pollen with enlarged interlayer distance was built by alkali activation method, applying in electrocatalytic n-valeraldehyde oxidation reaction. The enlarged interlayer distance was verified by X-ray diffraction (XRD) and high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM). Electrocatalytic experiments consequences showed activated biomass derived carbon possessed a higher electrocatalytic activity and octane selectivity than unactivated catalyst. Systematic tests and in situ infrared experiments demonstrated that enlarged interlayer distance was positively correlated with specific surface area of catalysts, large specific surface area provided abundant absorption sites, facilitated the adsorption for n-valeraldehyde, and further promoted the transformation of n-valeraldehyde to octane. This work also provides a new avenue for creating high-performance electrocatalysts in terms of lattice engineering. [ABSTRACT FROM AUTHOR]

Lead-free antiferroelectric AgNbO3 ceramics have garnered extensive attention due to their rapid charge/discharge capabilities and environmentally friendly nature, holding immense potential for energy storage applications. However, the practical utilization of AgNbO3 has been hindered by its low energy storage density. This study employed an A/B-site co-doping strategy, which yielded positive effects on the energy performance of AgNbO3 ceramics. By modifying the A/B-sites with equivalent amounts of Bi3+ and Y3+ ions, enhanced maximum polarization, improved breakdown field, and slimmer hysteresis loops were simultaneously achieved, as the combined effects of refined grain size, wider optical bandgap, and randomly distributed antiferroelectric nanodomains, which were verified through the scanning electron microscope, transmission electron microscope, and ultraviolet–visible spectrum. As a consequence, a high energy storage density of 5.40 J/cm3 accompanied by an energy storage efficiency of 56.5% was achieved in the Ag0.97Bi0.01Nb0.994Y0.01O3 ceramic under a relatively low electric field of 190 kV/cm. This study underscores the effectiveness of A/B-site aliovalent co-doping as a viable strategy for developing high-performance ceramic capacitors for energy storage applications. [ABSTRACT FROM AUTHOR]

The present investigation focused on the effect of boron nitride quantum dots (BNQDs) as a filler on the optical properties of polyvinyl butyral (PVB) nanocomposites. Herein, polymer nanocomposite films with advanced UV protection and high photoluminescence properties were successfully synthesized. Polymer nanocomposite films were produced by adding BNQDs to the polymer in different ratios by a simple solution forming and casting method. The films were decomposed at different UV degradation times, and their UV protective properties were tested. The structural, morphological, optical and chemical interaction of BNQDs/PVB nanocomposites was confirmed by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), Fourier Transform Infrared (FTIR), micro‐Raman spectroscopy, ultraviolet and visible (UV–Vis), and photoluminescence (PL) analyzes. As the amount of BNQDs in the polymer increased, the intensity of the bright images separated from the polymer also increased. TEM images confirmed the good distribution of quantum dots in PVB polymer matrix. Polymer composites doped with 0.25% and 0.4% BNQDs show excellent UV‐shielding properties as the transmittance in the UV region decreased about 69% and 95%, respectively. As the addition of BNQDs into the polymer increased, the PL emission of the pure PVB film, which showed almost no emission, increased significantly. [ABSTRACT FROM AUTHOR]

To expand the market capacity of p‐diethylbenzene (PDEB), core‐shell zeolite (TS‐1@MCM‐48) is designed as a catalyst for PDEB oxidation. TS‐1@MCM‐48 catalyst is synthesized by in‐situ crystallization method and characterized by X‐ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X‐ray photoelectron spectroscopy (XPS), N2 adsorption‐desorption, in‐situ electron paramagnetic resonance (EPR) and 29Si nuclear magnetic resonance (29Si MAS‐NMR). Oxidation of PDEB by H2O2 was investigated systematically in liquid phase. The conversion of PDEB over TS‐1@MCM‐48 was 28.1 % and the total selectivity was 72.6 %, where the selectivity of EAP (p‐ethylacetophenone) and EPEA (4‐ethyl‐α‐methylbenzyl alcohol) was 28.6 % and 44.0 %, respectively. Compared with TS‐1 and MCM‐48 zeolite, the conversion rate of reactants and the selectivity of products have been significantly improved. The catalytic performance of TS‐1@MCM‐48 is derived from its well‐crystallized microporous core and mesoporous shell with regular channels, which make active sites of TS‐1 zeolite in the catalyst be fully utilized and mass transfer resistance be largely reduced. Further through theoretical calculation, we propose that the oxidation of PDEB is the result of the combination and mutual transformation of free radical process and carbocation process. Core‐shell structure ensures the conversion rate of raw materials and improves the selectivity of products. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) are arguably the most promising in terms of application among the noble metal nanoparticles. As such, researchers have dedicated a considerable amount of energy towards the synthesis of novel gold nanoparticles with different morphology and size, which in turn affect its potential application. This study synthesized novel spherical-shaped AuNPs via green reduction of gold ion in an aqueous solution of HAuCl4.3H2O in the presence of trimethyl chitosan as a stabilizing agent and pressurized H2 gas as a reducing agent on an ice water. The size, morphology, chemical composition, chemical environment and optical activities were examined by scanning electron microscope (SEM), high-resolution transmission electron microscope (HRTEM), x-ray photoelectron spectroscopy (XPS), and ultraviolet–visible spectroscopy (Uv–Visible), respectively. The average particle size of AuNPs is 37 nm while HR-TEM revealed a unique spherical morphology. The Tauc’s plot calculation revealed a band gap of 5.0 eV. This unique morphology and optical local field enhancement in plasmonic nanocomposites could be suitable alternative for conducting devices and photocatalysis. [ABSTRACT FROM AUTHOR]

We propose the strain-induced solid-state coating process of twinning-induced plasticity (TWIP) steel with zinc, achieved through concurrent rolling of TWIP steel and zinc sheets. Our study explores the effects of strain, strain rate, and rolling temperature on the morphology and intermixing at the Zn-TWIP steel interface. We found that two simultaneous mechanisms are responsible for the formation of a joint interface between the sheets in the rolling temperature range of 100–380 °C, namely mechanical intermixing at the interface and accelerated diffusion along moving dislocations and other defects introduced during rolling. Since it is impossible to deconvolute these mechanisms, we introduced the concept of an 'apparent diffusion coefficient' to represent the diffusion-like mass transfer resulting from mechanical intermixing and diffusion. These diffusion coefficients were determined by primary electron energy variation method in scanning electron microscope and by energy-dispersive X-ray spectroscopy in transmission electron microscope. Notably, these diffusion coefficients were found to be higher than the grain boundary diffusion coefficients of Zn in γ-Fe, primarily due to the dynamic nature of interface microstructure formation during rolling. [ABSTRACT FROM AUTHOR]

The harsh service environment of aeroengine hot-end components requires superalloys possessing excellent antioxidant properties. This study investigated the effect of pre-strain on the oxidation behavior of polycrystalline Ni3Al-based superalloys. The growth behaviors of oxidation products were analyzed by scanning electron microscope, transmission electron microscope, X-ray Photoelectron Spectroscopy and Raman spectroscopy. The results indicated that the 5% pre-strained alloys exhibited lower mass gain, shallower oxidation depth and more compact oxide film structures compared to the original alloy. This is mainly attributed to the formation of rapid diffusion paths for Al atoms diffusing to the surface under 5% pre-strain, which promotes the faster formation of protective Al2O3 film while continuing to increase the pre-strain to 25% results in less protective transient oxidation behavior being aggravated due to the increase in dislocation density within the alloy, which prevents the timely formation of the protective Al2O3 film, resulting in uneven oxidation behavior on the alloy. [ABSTRACT FROM AUTHOR]

In this work, UV-Vis spectrophotometry, High Resolution Scanning Transmission Electron Microscopes and selected experimental conditions were used to screen the colloidal system. The obtained results complement the established knowledge regarding the mechanism of nanoparticle formation. The process of gold nanoparticles formation involves a two-step reduction of Au ions to Au(0); atom association and metastable cluster formation; autocatalytic cluster growth; ultra-small particle formation (1–2 nm, in diameter); particle growth and larger particles formation; and further autocatalytic crystal growth (D > 100 nm). As a reductant of Au(III) ions, a cinnamon extract was used. It was confirmed that eugenol as one of the cinnamon extract compounds is responsible for fast Au(III) ion reduction, whereas cinnamaldehyde acts as a gold-particle stabilizer. Spectrophotometry studies were carried out to track kinetic traces of gold nanoparticle (D > 2 nm) formation in the colloidal solution. Using the Watzky—Finke model, the rate constants of nucleation and autocatalytic growth were determined. Moreover, the values of energy, enthalpy and entropy of activation for stages related to the process of nanoparticle formation (Index 1 relates to nucleation, and Index 2 relates to the growth) were determined and found to be E1 = 70.6 kJ, E2 = 19.6 kJ, ΔH1 = 67.9 kJ/mol, ΔH2 = 17 kJ/mol, ΔS1 = −76.2 J/(K·mol), ΔS2 = −204.2 J/(K·mol), respectively. In this work the limitation of each technique (spectrophotometry vs. HRSTEM) as a complex tool to understand the dynamic of the colloidal system was discussed. [ABSTRACT FROM AUTHOR]

Dressings with multiple functional performances (such as hemostasis, promoting regeneration, analgesia, and anti-inflammatory effects) are highly desired in orthopedic surgery. Herein, several new kinds of medicated nanofibers loaded with several active ingredients for providing multiple functions were prepared using the modified coaxial electrospinning processes. With an electrospinnable solution composed of polycaprolactone and fenoprofen as the core working fluid, several different types of unspinnable fluids (including pure solvent, nanosuspension containing tranexamic acid and hydroxyapatite, and dilute polymeric solution comprising tranexamic acid, hydroxyapatite, and polyvinylpyrrolidone) were explored to implement the modified coaxial processes for creating the multifunctional nanofibers. Their morphologies and inner structures were assessed through scanning and transmission electron microscopes, which all showed a linear format without the discerned beads or spindles and a diameter smaller than 1.0 μm, and some of them had incomplete core–shell nanostructures, represented by the symbol @. Additionally, strange details about the sheaths' topographies were observed, which included cracks, adhesions, and embedded nanoparticles. XRD and FTIR verified that the drugs tranexamic acid and fenoprofen presented in the nanofibers in an amorphous state, which resulted from the fine compatibility among the involved components. All the prepared samples were demonstrated to have a fine hydrophilic property and exhibited a lower water contact angle smaller than 40° in 300 ms. In vitro dissolution tests indicated that fenoprofen was released in a sustained manner over 6 h through a typical Fickian diffusion mechanism. Hemostatic tests verified that the intentional distribution of tranexamic acid on the shell sections was able to endow a rapid hemostatic effect within 60 s. [ABSTRACT FROM AUTHOR]

Recently, thermoelectric (TE) materials have seized great attention for their role in clean energy conversion applications. Cu2S are p-type super-ionic conductors featuring a narrow band gap of 1.7 eV while exhibiting outstanding thermoelectric characteristics. The Cu2S matrix and the CuO nanoinclusions were successfully synthesized via solvothermal and hydrothermal routes, respectively. The morphological observations made through scanning and transmission electron microscope ensured the homogeneous distribution of CuO nanoinclusions in the Cu2S matrix, hence, the formation of standard Cu2S/CuO composites. In this work, we have introduced a "combined strategy" to boost the figure of merit (zT). The Seebeck coefficient reached the maximum of 271.86 μVK−1 at 573 K for the 20 wt% CuO sample (a 71.45% gain when compared to the pure Cu2S) owing to the filtration of low-energy carriers at the CuO potential barriers (2.5 eV). The Cu2S/20 wt% CuO sample achieved the minimum thermal conductivity values. At 573 K, We recorded a vast power factor value of 952.66 μWm−1 K−2 (32.23% gain) for the Cu2S/15 wt% CuO sample. These values are vastly higher than previously reported for the copper sulfides-based TE materials. Consequently, an optimised zT value of 0.44 (214.29% gain) was accomplished for the Cu2S/15 wt% CuO sample at 573 K. The strategy presented in our study can also be extended to other TE materials, especially for the promising copper chalcogenides to improve their zT values. [ABSTRACT FROM AUTHOR]

In this article, the effect of Ce element on the microstructure and mechanical properties was studied by Ce addition to the hot‐formed steel. Scanning electron microscope and energy dispersive spectrometer (SEM‐EDS) was used to analyze the improvement effect of Ce on inclusions and the effect of inclusions on fracture behavior; Electron back scattering diffractometer (EBSD) was used to analyze the refinement and strengthening effect of Ce on martensitic grains; transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM) was used to analyze the microstructure strengthening effect and microalloying effect of solid solution Ce in hot‐formed steel. Through a systematic analysis of mechanical properties and microstructure, the mechanism of Ce enhances the strength and elongation of hot‐formed steel was clarified. Besides, this work provides a research basis for further improving the safety and machinability of hot‐formed steel. [ABSTRACT FROM AUTHOR]

In the current study, a novel electrochemical sensor has been developed for levofloxacin detection, by coating an Indium tin oxide (ITO) modified electrode with a thin film of Cu-nanoplatelets, WO3 quantum dots coupled to the g-C3N4 nanosheets. The prepared electrode was characterized using various analytical tools, including powder X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM) and Fourier-Transform Infrared spectroscopy (FT-IR). The electrochemical properties of levofloxacin (LEVO) were determined by performing cyclic voltammetry (CV) and amperometric tests. The hybrid electrode exhibits a well-defined peak around 1.2 V during the anodic potential scan, which was attributed to the (LEVO) oxidation process. The measured ultrahigh sensitivity is 0.786 µA µM−1 cm−2 for a linear range of 0–70 µM in the low concentration zone and 0.312 µA µM−1 cm−2 for a linear range of 120–870 µM in the high concentration zone. A good linear correlation between the peak current and LEVO concentration in the range of 0 to 70 µM was obtained through detection and quantification limits of 0.1 µM and 0.3 µM, respectively.The WO3/g-C3N4/Cu nanoparticles that modified the ITO electrode reveals high stability, reproducibility, and repeatability, as well as selectivity for LEVO in real water samples. Analyses were also conducted on the LEVO detection in the presence of interfering substances.As far as this paper is concerned, this is the first time that a ternary nanocomposite WO3/g-C3N4/Cu has been used to detect LEVO at low and high concentrations. Application of ITO/WO3/g-C3N4/Cu as an electrochemical sensor for LEVO [ABSTRACT FROM AUTHOR]

Fluoride ions, which interfere with the oxide formation on zirconium have been over-looked until recently. The effect of fluoride ions on oxide formation and dissolution behaviors in zirconium was investigated in this study. A detailed quantitative characterization of the oxide films formed on Zr702 immersed in a fluorinated nitric acid solution was performed using X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and representative high-angle annular dark-field scanning Transmission Electron Microscope, (TEM). The corrosion performance in a fluorinated nitric acid solution was discussed. The results reveal that the thickness of the oxide films immersed in the fluorinated nitric acid solution was between 42–48 nm, which is much thinner than that of the oxide layer (~98.85 nm thickness) in the F− free HNO3 solution. The oxide film was identified to be a nanocrystalline cluster, comprised of outermost HfO2 and HfF4 layers, sub-outer ZrO2 and ZrF4 layers, and an innermost Zr (F, O)3.6 layer. This fluoride species penetration through the oxide films indicated that the fluoride ions are responsible for the dissolution of the oxide film of Zr702. [ABSTRACT FROM AUTHOR]

Graphene nanoplatelets (GNPs) were synthesized by an electrochemical exfoliation method. Four various conditions of the electrochemical exfoliation process: (I) 1M NaOH with 4V, (II) 0.5M H2SO4 with 5V, (III) a mixture of 1M NaOH and 0.5M H2SO4 with 5V, and (IV) a twostep process of 1M NaOH with 4V and 0.5M H2SO4 with 5V, were compared. The as-synthesized GNPs obtained from all conditions were characterized by Raman spectroscopy and X-ray diffraction. The two-step process provided the GNPs with the low defect concentration and the lowest number of layers. Moreover, confirmed by field emission scanning and transmission electron microscopes (FE-SEM and TEM), the GNPs obtained from the two-step process were multilayer graphene. The GNPs obtained from each condition were added into an ultraviolet-cured acrylate adhesive to fabricate electrically conductive acrylate adhesive (ECAA). The GNPs acted as fillers to play an important role in conducting the electrical network of the ECAA without any other additive. The van der Pauw method was conducted to measure the electrical resistivity of the ECAA. The ECAA, containing 5wt% of the obtained GNPs from the two-step process, had the lowest resistivity when compared to the ECAA which contained the obtained GNPs from other conditions. We found that the percolation threshold of the ECAA, containing the obtained GNPs from the two-step process, was at 3.26 wt%. Last, 6.92 wt% of the GNPs reached the lowest resistivity at 1.09Ω·cm. [ABSTRACT FROM AUTHOR]

Silicon nitride (Si3N4) has great potential for applications in photoelectric and semiconductor fields. In this study, a novel strategy of fabricating Si3N4 crystals is reported, and the morphology of α-Si3N4 can be controlled. The aBN/SiO2/Si wafers were designed and irradiated by a high-energy electron beam for 2 min using home-made equipment. Tree-like α-Si3N4 dendrites and [001]-oriented unbranched α-Si3N4 whiskers can be synthesized by controlling the electron beam energy. Related formation mechanisms were analyzed based on componential and structural characterization using a scanning electron microscope and high-resolution transmission electron microscope. In addition, photoluminescence measurements indicate that the synthesized α-Si3N4 exhibit unique photoluminescence properties. This is attributed to α-Si3N4 forming abundant Si–Si bonds, Si dangling bonds, N dangling bonds and oxygen bonds in the synthesis process. These findings provide new insights into fabricating high-quality Si3N4 crystals, as well as developing related high-performance micro- or nano-devices. [ABSTRACT FROM AUTHOR]

Ruthenium (Ru) doped antimony tungstate microflowers, prepared through hydrothermal process, have been investigated for simultaneous adsorption and photocatalysis. The pattern of evolution of microflower structures, however, can be tailored by the synthesis period. This change is observed from the field effect scanning electron microscope and transmission electron microscope images. A possible mechanism behind this morphological change has been developed. An argument based on the zeta potential may be responsible for this distinct morphology due to the strong electrostatic interactions. The variation of a particular x-ray diffraction peak corresponding to the plane { 012 } with variation of Ru doping percentage shows the decrease in crystallinity along the perpendicular direction to this plane. Besides, the optimum Ru doping percentage is evaluated on the basis of photocatalytic efficiency towards methylene blue (MB) degradation under visible light. The highest dye removal efficiency is observed for 2% Ru doped Sb2WO6 (SWO) adsorbing 97% of the MB dye followed by photocatalytic degradation of almost 64% of the remaining dye in 80 min. Furthermore, using different dyes, it is concluded that Ru–SWO showcases high adsorption toward the cationic dyes while it neither adsorbs the anionic dye nor displays photocatalytic degradation. [ABSTRACT FROM AUTHOR]

Background and objectives: Microbial cells capability to tolerate the effect of various antimicrobial classes represent a major worldwide health concern. The flexible and multi-components nanocomposites have enhanced physicochemical characters with several improved properties. Thus, different biological activities of biosynthesized starch/silver-selenium nanocomposite (St/Ag-Se NC) were assessed. Methodology: The St/Ag-Se NC was biosynthesized using Cladosporium cladosporioides CBS 174.62 (C. cladosporioides) strain. The shape and average particle size were investigated using scanning electron microscope (SEM) and high-resolution transmission electron microscope (HR-TEM), respectively. On the other hand, the St/Ag-Se NC effect on two cancer cell lines and red blood cells (RBCs) was evaluated and its hydrogen peroxide (H2O2) scavenging effect was assessed. Moreover, its effects on various microbial species in both planktonic and biofilm growth forms were examined. Results: The St/Ag-Se NC was successfully biosynthesized with oval and spherical shape and a mean particle diameter of 67.87 nm as confirmed by the HR-TEM analysis. St/Ag-Se NC showed promising anticancer activity toward human colorectal carcinoma (HCT-116) and human breast cancer (MCF-7) cell lines where IC50 were 21.37 and 19.98 µg/ml, respectively. Similarly, little effect on RBCs was observed with low nanocomposite concentration. As well, the highest nanocomposite H2O2 scavenging activity (42.84%) was recorded at a concentration of 2 mg/ml. Additionally, Staphylococcus epidermidis (S. epidermidis) ATCC 12,228 and Candida albicans (C. albicans) ATCC 10,231 were the highly affected bacterial and fungal strains with minimum inhibitory concentrations (MICs) of 18.75 and 50 µg/ml, respectively. Moreover, the noticeable effect of St/Ag-Se NC on microbial biofilm was concentration dependent. A high biofilm suppression percentage, 87.5% and 68.05%, were recorded with S. epidermidis and Staphylococcus aureus (S. aureus) when exposed to 1 mg/ml and 0.5 mg/ml, respectively. Conclusion: The biosynthesized St/Ag-Se NC showed excellent antioxidant activity, haemocompatibility, and anti-proliferative effect at low concentrations. Also, it exhibited promising antimicrobial and antibiofilm activities. [ABSTRACT FROM AUTHOR]