Cai, RuiWang, ZhouliYuan, YahongYue, Tianli...
10页查看更多>>摘要：Bacterial drug resistance caused by the abuse of antibiotics poses a serious threat to human health. Thus, the development of alternative strategies for the replacing of antibiotics is necessary. Herein, a hierarchical three-dimensional Bi2S3 (BS) nanoflowers were facile fabricated and employed as supporter for the growth of silver nanoparticles (Ag NPs). Combining the excellent antimicrobial activity of Ag NPs, the as-resulted Ag/BS exhibited broad-spectrum antibacterial activity against pathogenic bacteria. Investigation on antibacterial mechanism revealed the treatment of Ag/BS damages the bacterial cell membrane, leading to the loss of intracellular substances. The compromised membrane caused the reduction of membrane bound enzymes activity, resulting in the arrest of metabolic activity. Simultaneously, Ag/BS broke the bacterial antioxidant defense system by raising the intracellular ROS levels, caused the oxidative damage, resulting in the loss of bacterial viability. Moreover, the satisfactory biocompatibility and effective antibacterial performance of Ag/BS were confirmed by performing in vitro cytotoxicity and in vivo antibacterial assay. Accordingly, this work opens up possibility for the construction of Bi2S3 based multifunctional nanomaterials and its application for pathogenic bacteria control. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
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Elsevier
Corthay, ShaktiKutzhanov, Magzhan K.Matveev, Andrei T.Bondarev, Andrey, V...
11页查看更多>>摘要：Al/h-BN composites with high tensile and compressive strength at room and elevated temperatures, as well as enhanced ductility, were obtained by a combination of ball milling (BM) and spark plasma sintering (SPS) using Al and hexagonal BN nanopowders (0, 1, 2, 3, 4, 5, and 10 wt% of h-BN). The use of two types of nanopowders is intended to ensure uniform distribution of the reinforcing phase and improve Al-BN chemical interaction at the manufacturing stages by increasing the surface-to-volume ratio. Due to Al with h-BN interaction, the Al/h-BN composites were simultaneously strengthened by three types of nanoparticles: Al2O3, AlN(O) and h-BN, predominantly located along the Al grain boundaries. Compared to BM +SPS aluminum, the tensile strength of Al-2 wt%BN composite increased by 82% (25 degrees C), 64% (300 degrees C), and 65% (500 degrees C), and the compressive strength by 107-119% (25-500 degrees C) while maintaining high elongation to failure in tension (13.6%, 11.6% and 10.8%) and compression (12.6%, 13.1% and 8.1%) at 25 degrees C, 300 degrees C, and 500 degrees C, respectively. In terms of combination of tensile and compressive strength at room and elevated temperatures, the Al/h-BN materials are superior to many other Al-based composites. The high strength and relative elongation to fracture of the Al/h-BN composites can be explained by the formation of a heterogeneous microstructure consisting of pure Al grains surrounded by a metal-matrix composite material with fine metal grains and reinforcing ceramic nanoinclusions. The obtained results significantly expand the scope of Al/h-BN materials, since their strength at 500 degrees C is higher than that of pure Al at room temperature. (c) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Dehua, WangLonglong, JiangYang, YuYe, Lu...
8页查看更多>>摘要：Traditional inorganic ceramic materials usually exhibit macroscopic rigidity due to the incompatibility to the flexibility mechanism of traditional flexible materials such as sliding of polymer chains or atoms. Recently, new form of nanotechnology has been proposed to be capable of preparing inorganic flexible materials. In this paper, inorganic luminescent material (Ba,Ca)TiO3:Pr3+ was prepared into the flexible form by electrospinning technology, and the macroscopic flexibility of pure inorganic (Ba,Ca)TiO3:Pr3+ was systematic investigated. The crystal grain size was found to grow after higher temperature calcination, which benefits luminescence. However, lowering the calcination temperature will further optimize the flexibility of the membrane. This study shows that fibrous membrane fabrication is an applicable flexible fabrication strategy for inorganic oxides, which provides an important reference for the design of flexible materials. (C)& nbsp;2022 Published by Elsevier B.V.
原文链接:- NSTL
- Elsevier
Wang, TianjianZhang, HongLiu, ChunhuaGong, Xiufang...
11页查看更多>>摘要：The effect of temperature on the tensile behavior and deformation mechanisms in a single crystal super alloys CMSX-4 is addressed and deduced by transmission electron microscopy in the temperature range from room temperature to 1100 degrees C. It is found that the tensile yield strength reaches a peak at 800 degrees C. And then, the yield strength decreases with increasing temperature. At room temperature, anti-phase boundary shearing dominates the plastic deformation. From 800 degrees C to 850 degrees C, the plastic deformation mechanism is mainly controlled by stacking fault shearing. The Kear-Wilsdorf locks have also appeared. When the temperature reaches at 950 degrees C, dislocation loops with anti-phase boundary shearing of the xfffc; precipitates are presented. Above 950 degrees C, the plastic deformation mechanism is processed by the rafted structure of the precipitates by-passing, i.e., Orowan by-passing and dislocation climb. Finally, according to the experimental results, the variety of stacking faults with temperatures and the relationship between the yield strength and plastic deformation mechanism are discussed. (c) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Jiang, XueWang, ZhihaoZhang, MengxuanWang, Mutong...
10页查看更多>>摘要：In recent years, inhibition of photoinduced electron and hole recombination is considered as a breakthrough to improve the photocatalytic degradation of pollutants. In this study, we successfully loaded ZnFe2O4 (ZFO) microsphere onto BiFeO3 (BFO) microcubes via a simple hydrothermal method, and intimate interface between BFO and ZFO was constructed. Under the effect of heterojunction between BFO and ZFO, the recombination rate of photogenerated electron-hole pairs was decreased significantly, leading to the enhanced photocatalytic effect. The photocatalytic experiments show that the degradation efficiency of BFO/ ZFO-10% composite for tetracycline and methylene blue are 1.63 and 1.38 times higher than that of pure BFO. In addition, four cycles experiment also proved that BFO/ZFO has good stability and excellent magnetic recovery properties. A possible carrier transfer path on the base of the direct Z-scheme mechanism in composite was proposed. This study provides a useful guide toward the design of the highly efficient and magnetic collectable photocatalysts by the introduction of magnetic component and the construction of heterojunction, and as-synthesized BFO/ZFO was proved to be a promising photocatalyst for the elimination of toxic organic molecules in groundwater. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Zeng, Hong-YanXiong, JieXu, ShengAn, De Shun...
11页查看更多>>摘要：A novel p-n heterostructure Ag-Ag2MoO4/polyaniline (Ag-Ag2MoO4/PANI) composite was synthesized via a facile oxidation polymerization followed by co-precipitation. The surface morphology, structure, optical and photoelectrochemical properties of the as-prepared composites were determined using various techniques, and the photocatalytic activity was evaluated using chromium (VI) [Cr(VI)] and methyl orange (MO) as target inorganic and organic pollutants under visible-light irradiation. The results showed that the p-n heterostructure was formed between Ag-Ag(2)MoO(4)and PANI, which could effectively promote the rapid transfer and separation of the photogenerated electron-hole pairs. At the same time, the metallic Ag nanoparticles on the surface harvested visible-light photons and generated extra plasmonic hot electrons to enhance the photocatalytic activity. As expected, the optimal Ag-Ag2MoO4/PANI(0.10) exhibited high photo catalytic activity in the Cr(VI) reduction and MO degradation owing to the fast separation and transfer of the electron-hole pairs. Moreover, trapping experiment revealed that center dot OH and center dot O-2(-) played a vital role during the MO degradation process. Based on various characterizations and experimental results, the possible photocatalytic mechanisms were proposed. This work gave a simple method to construct p-n heterostructure photocatalysts for environmental restoration. (C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Huang, ZhenHe, XikouChen, KunWang, Xitao...
11页查看更多>>摘要：The solidification characteristics of C700R-1 alloy was investigated by DSC analysis, in-situ observation, quenching experiment and Thermo-Calc calculation. The segregation behavior during solidification was analyzed by Scanning Electron Microscope and Electron Probe Microanalysis. At the initial stage of solidification, the volume fraction of liquid experienced a steep decrease, accompanied by a rapid formation of dendrites. The residual liquid solidified slowly due to segregation at the final stage. Al, Ni, W and Co elements segregated in the dendrite stems, while Ti, Nb and Mo were enriched in the interdendritic, in which MC carbides also precipitated. At the end of solidification, the segregation of Mo and Cr is further aggravated, resulting in extremely low solidus and formation of eutectic region. The study on the solidification characteristics of C700R-1 alloy demonstrates that aggravation of segregation leads to deterioration of the solidification conditions.(c) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Trinkler, LaimaAulika, IlzeKrieke, GunaNilova, Dace...
10页查看更多>>摘要：Wurtzite Zn1-xMgxO epilayers (x = 0, 0.26, 0.44, 0.49, 0.66) grown by the plasma-assisted molecular beam epitaxy on ScAlMgO4 substrate were characterized using the methods of optical spectroscopy: spectroscopic ellipsometry (SE), optical absorption (OA), and photoluminescence (PL). The complex dielectric function in the spectral range of 210-1690 nm, band gap width, exciton absorption and emission parameters, and film quality were studied and discussed. Individual characterization of samples was provided by combining SE and OA measurement results. The observed increase of the band gap up to 4.35 eV with the rise of the MgO content allowed the recommendation of the wurtzite Zn1-xMgxO epilayers as material for UV sensors. The origin of defects hampering the practical application of the materials was discussed.(C) 2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Novitskii, AndreiSerhiienko, IlliaNovikov, SergeyKuskov, Kirill...
8页查看更多>>摘要：Among layered oxygen-containing compounds, BiCuSeO is one of the most promising candidates for thermoelectric applications due to its intrinsically low thermal conductivity and good thermal stability. However, the rather poor electrical conductivity of pristine BiCuSeO hinders its potential. Further enhancement of the thermoelectric performance by single doping at Bi site is limited mainly due to dramatic decrease of carrier mobility. Thus, new strategies, such as dual doping or doping with variable-valence elements seem to be promising. Along with that, the development of a fast and scalable synthesis route is essential for the industrial-scale fabrication of thermoelectric materials. Hence, in this paper, Bi1-xSmxCuSeO samples (0 <_ x <_ 0.08) have been synthesized with a simple and scalable reactive sintering process. For comparison, Bi1-xSmxCuSeO oxyselenides were also obtained by the conventional solid-state route. Our results highlight that, Sm for Bi substitution increases the electrical conductivity by 1.5-2 times and decreases the Seebeck coefficient by ~1.4 times at 873 K for both series. Overall, considering the increase of lattice thermal conductivity upon doping and not optimized power factor, the figure of merit zT is reducing upon doping.(C)& nbsp;2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
Streltsov, Sergey V.Ryltsev, Roman E.Chtchelkatchev, Nikolay M.
6页查看更多>>摘要：In recent years, A-site ordered half-doped double-perovskite manganites RBaMn2O6 (R=rare earth) have attracted much attention due to their remarkable physical properties and a prospect of application as magnetoresistive, multiferroic, and oxygen storage materials. The nature of the ground state in RBaMn2O6 as well as sequence of phase transitions taking place at cooling are not yet well understood due to complexity in both experimental and theoretical studies. Here we address the origin of the ground-state structure in PrBaMn2O6 as well as its electronic and magnetic properties. Utilizing GGA+U approach and specially designed strategy to perform structural optimization, we show that the system has two competing AFM-A and AFM-CE magnetic structures with very close energies. The AFM-A structure is a metal, while AFM-CE is an insulator and the transition to the insulating state is accompanied by the charge Mn3+/Mn4+, and orbital 3x(2) - r(2)/3y(2) - r(2) orderings. This orbital ordering results in strong cooperative Jahn-Teller (JT) distortions, which lower the crystal symmetry. Our findings give a key to understanding contradictions in available experimental data on PrBaMn2O6 and open up the prospects to theoretical refinements of ground state structures in other RBaMn2O6 compounds. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
原文链接:- NSTL
- Elsevier
