查看更多>>摘要：? 2022 Elsevier B.V.For the first time, the author reported the fabrication and characterizations of Co2+ doped Zn2SiO4 (Co2+: Zn2SiO4) using the recycled waste white rice husk ash (WRHA) based on empirical formula (Co3O4)1.0[(ZnO)55.0(WRHA)45.0]99.0 and produced by using melt-quenching technique. The precursor glass was heat treated at 700 ℃ until 950 ℃. The X-ray diffraction (XRD) result of Co2+: Zn2SiO4 showed that β- Zn2SiO4 started to form at 750 ℃ and single phase of α-Zn2SiO4 remain stable at 950 ℃. The Fourier transform infrared spectroscopy (FTIR) confirmed the formation of Co2+: Zn2SiO4 by showing eight significant vibrational bands. One triplet absorption band occurred at around 450–700 nm attributed to 4A2 → 4T1 (4P) optical transition of Co2+ ions that gives blue color towards the Co2+: Zn2SiO4 sample. Emission spectroscopy of Co2+: Zn2SiO4 exhibit five different peaks corresponded to blue emission (~416 nm, ~441 nm, ~461 nm and ~481 nm) and green emission (~527 nm) under excitation at 325 nm. Such luminescence properties making Co2+: Zn2SiO4 as a potential phosphor material especially in providing blue emission supported by the excellent dielectric properties.
查看更多>>摘要：? 2022 Elsevier B.V.This work presents a nanocomposite-based humidity sensor based on zinc oxide nanostructured powder (ZNP) nanoparticles that achieves a maximum enhancement in the humidity sensing performance at room temperature due to the introduction of different amounts of reduced graphene oxide (rGO) loading from 0.5 wt% to 2.0 wt%. The rGO/ZNP (rZNP) nanocomposite-based humidity sensor was fabricated by using cellulose filter paper as a substrate and clear paper glue as a binder through a facile brush printing method. FESEM, EDS, XRD, HRTEM, XPS, and Raman spectroscopy were employed to investigate the properties of the ZNP and rZNP nanocomposites. The presence of an rZNP nanocomposite with quasi-spherical ZNP nanoparticles that are securely attached and anchored with rGO sheets was confirmed through HRTEM micrographs. Raman spectroscopy analyses confirm and validate the formation of hybrid nanostructures with the presence of distinctive bands related to ZNP and rGO. The presence of oxygen vacancy defects and oxygen-related chemical bonds on the surface of the rZNP nanocomposite, which yields enhanced sensor performance, is revealed by XPS analysis. The rZNP nanocomposite-based humidity sensor with 1.0 wt% rGO loading (rZNP-1.0) had a maximum sensing response of 99.42% and exhibited the highest sensitivity towards humidity changes (172 or 29.2 MΩ/%RH), which was substantially better than the other tested samples.
查看更多>>摘要：? 2022 Elsevier B.V.All-solid-state batteries (ASSBs) have high safety and high energy density. Li10SnP2S12 sulfide solid electrolyte has attracted extensive attention due to its low fabrication cost and outstanding performance in ASSBs. However, its ionic conductivity and stability to lithium and air need to be further improved. Here, in order to avoid the formation of impurities related to Sn-related compounds, the content of SnS2 in the raw materials is reduced, and to improve ionic conductivity and stability to lithium and air. The S site is doped with O by the solid-phase sintering method, and a series of Li10Sn0.95P2S11.9?xOx (0 ≤x ≤ 1) electrolytes are prepared. Li10Sn0.95P2S11.4O0.5 (LS0.95PSO0.5) has a high ionic conductivity of 3.96 mS cm?1 and low activation energy after cold pressing. According to the Hard-Soft-Acid-Base theory, doping O into the electrolyte in advance will improve the stability. The ionic conductivity decay of LS0.95PSO0.5 after exposure to air is smaller, which proves that O doping improves the air stability of the electrolyte. LS0.95PSO0.5 also shows good stability to lithium. The assembled LNO@LCO/LS0.95PSO0.5/Li-In ASSB exhibits a high first-cycle discharge capacity of 133 mA h g?1 and good cycling stability.
查看更多>>摘要：? 2022 The AuthorsThe addition of Al to the A1 CrFeCoNi alloy has been shown to promote the formation of intermetallic phases, offering possibilities for the development of alloys with advantageous mechanical properties. However, despite numerous experimental investigations, there remain significant uncertainties as to the phase equilibria in this system particularly at temperatures below 1000°C. The present study makes a systematic assessment of the literature data pertaining to the equilibrium phases in alloys of the AlxCrFeCoNi system. Two alloys, with atomic ratios, x = 0.5 and 1.0, are then selected for further experimental investigation, following homogenisation (1200°C/72 h) and subsequent long-duration (1000 h) heat-treatments at 1000, 850 and 700°C. The Al0.5 alloy was found to be dual-phase A1 + B2 in the homogenised condition and following exposure at 1000°C but D8b phase precipitates developed following heat-treatment at the lower temperatures. In the Al1.0 alloy, B2, A2 and A1 phases were identified in the homogenised condition and at 1000°C. At 850 and 750°C, the A2 phase was replaced by the D8b phase. These experimental observations were used alongside literature data to assess the veracity of CALPHAD predictions made using the TCHEA4 thermodynamic database.
查看更多>>摘要：? 2022 Elsevier B.V.Two samples of an α + β Ti-4Al-4Mo-4Sn-0.5Si (wt%) alloy, one with fine prior β grains and a heterogeneous microstructure and the other with coarse prior β grains and a homogeneous microstructure were prepared by extrusion of compacts of TiH2/Al/Mo/Sn/Si powder blend at 1200 and 1300 °C respectively. The heterogeneous microstructure is manifested by softer Mo-rich regions with a full α/β lamellar structure containing a high number density of parallel and nanometer sized FCC δ (TiH) needles in a harder matrix with a microstructure consisting of interweaved α plates and β transformed structure (βt) domains and grain boundary α (GB α) layers. The matrix also contains a small fraction of Sn-rich regions which have the same microstructure as the matrix. The Mo-rich and Sn-rich regions form due to the limited diffusion of Mo and Sn alloying elements. This heterogeneous microstructure sustains a high tensile yield strength of 1199 MPa, a high strain hardening rate, and an excellent tensile ductility of 12.0%. In contrast, the homogeneous microstructure comprising of interweaved α plates and βt domains together with GB α layers sustains a similar high strength, but a clearly lower strain hardening rate and a significantly lower tensile ductility of 3.5%. Non-homogeneous deformation capacity, the release of energy by forming numerous microcracks and the intermittent growth of microcracks of the heterogeneous microstructure suggest that this microstructure has a high plasticity and high resistance to the growth of microcracks.
查看更多>>摘要：? 2022 Elsevier B.V.In this study, we developed fast and highly sensitive, label-free Ca-doped cupric oxide (CuO) based chemiresistive biosensors to detect C-reactive protein (CRP). The Successive Ionic Layer Adsorption and Reaction (SILAR) method was used to deposit pure and Ca-doped CuO thin films on interdigitated gold electrodes. Film surfaces were functionalized with monoclonal anti-C-reactive protein antibody (anti-CRP) by random physisorption method. Sensor fabrication steps were monitored using the linear sweep voltammetry method. Scanning electron microscopy was used to investigate the surface morphology. Energy-dispersive X-ray spectroscopy was used to determine the elemental composition. The structure of the films was investigated by the powder X-ray diffractometry method. Sensor parameters were determined by the change in sensor resistance over time. The sensors showed a good response to CRP with a linear detection range of 0.1–5.0 μg/ml, which was within the clinically significant range. Detection limits of 49.61 and 48.81 ng/ml were estimated using the standard deviation of the y-intercept and the standard deviation of the regression line, respectively. Dynamic response times of all fabricated sensors were found to be less than 30 s
查看更多>>摘要：? 2022 Elsevier B.V.The current work reports the synthesis of Bi1?xSrxFeO3 (SBFO; x = 0.0, 0.15, 0.25, 0.35) nanoparticles by sol-gel method and study of its structural and piezoelectric properties. X-ray diffraction identifies the phase transformation from rhombohedral to cubic of BiFeO3 upon doping of Sr. X-ray photoemission spectroscopy revealed that Sr doped BiFeO3 nanoparticles are rich with oxygen vacancies compared to the bare BiFeO3 nanoparticles. The highest maximal polarization value of 6.74 μC cm?2 and remnant polarization 4.20 μC cm?2 are observed for BiFeO3 with 25% of Sr. The SBFO-PENG with 25% of Sr content device provides output voltage and current of 6.35 V and 0.64 μA under pushing tester with 1 Hz frequency, which is higher to that for a bare BiFeO3 PENG. It also exhibits high mechanical robustness, and much stable and durable output even after 1500 s. A maximum power density of ~ 0.31 μWcm?2 was achieve at a resistive load of 108 Ω. The SBFO-PENG device's feasibility is tested by trigging commercial electronics such as charging capacitors and lighting the LED, and it can drive a 0.47 μF capacitor to store the energy of 7.29 μJ within 500 s under pushing tester.
查看更多>>摘要：? 2022 Elsevier B.V.Zr-V-Fe alloys are promising getter materials due to their remarkable hydrogen storage properties. In this work, the effects of preparation methods including annealing, melt-spinning, and melt-spinning & annealing on the microstructure as well as the activation properties and hydrogen absorption properties of Zr7V5Fe alloy are systematically investigated. Phase structure investigations show that annealed alloys have the largest cell volume of the main hydrogen-absorbing phase ZrV2. Compared to annealed alloys, the cell volume of α-Zr phase and ZrV2 phase is smaller in melt-spun alloys. As for the melt-spun & annealed alloy, the cell volume of ZrV2 phase decreases and the cell volume of α-Zr phase increases after annealing. And the PCT curves show that with the cell volume of the ZrV2 phase increasing, the plateau pressure decreases while the hydrogenation capacity increase accordingly. As a result, the annealed alloy has the lowest plateau pressure about 0.02 Pa and the highest hydrogenation capacity about 1.4 wt% at 623 K. The kinetic curves illustrate that the hydrogen absorption process is diffusion-controlled for all of the alloys. The melt-spun & annealed alloy has the best hydrogen absorption kinetic performance because it has a well homogeneous distribution of α-Zr phase after melt-spinning and annealing treatment. Melt-spun as well as melt-spun & annealed alloys have no incubation period and exhibit superior activation properties compared to annealed alloys. This is due to the higher content of Zr elements and thinner passivation layer on the surface of melt-spun and melt-spun & annealed alloys than that of annealed alloy.
查看更多>>摘要：? 2022 Elsevier B.V.Pure red fluorescence generated by near infrared (NIR) excitation is desired for bio-imaging with high biological penetration, but without cell damage or multi-photon photo-toxicity. In this work, β-NaYF4:Er3+ and β-NaYF4:Er3+,Tm3+ microcrystals were synthesized using a novel hydrothermal method. β-NaYF4:Er3+ microcrystals exhibited intense green and red up-conversion emissions under 976 nm laser diode excitation. The introduction of Tm3+ ions into β-NaYF4:Er3+ resulted in strong inhibition of green up-conversion emission (Er3+:2H11/2 /4S3/2→4I15/2) and, consequently, red up-conversion emission (Er3+:4F9/2→4I15/2) was significantly promoted. To simultaneously restrain green up-conversion emissions and enhance red up-conversion emissions, the optimal concentrations of Er3+ and Tm3+ ions were determined to be 20 mol% and 2.0 mol%, respectively. The red/green up-conversion emission intensity ratio increased from ~1.80 (β-NaYF4:20Er3+, mol%) to ~78 (β-NaYF4:20Er3+,2Tm3+, mol%) after the addition of 2 mol% Tm3+ ions to β-NaYF4:20Er3+ (mol%). The red up-conversion emission intensity of β-NaYF4:20Er3+,2Tm3+ was stronger than that for commercial red up-conversion phosphors (NaYF4 and ZnF2) under the same experimental conditions. Based on the results of the emission spectra, luminescence rise, and decay profiles, the mechanism of enhanced red up-conversion emission by Tm3+ ion co-doping in β-NaYF4:20Er3+,2Tm3+ (mol%) was proposed. The bio-fluorescence experiment under NIR excitation proves that β-NaYF4:Er3+,Tm3+ microcrystals have potential applications in bio-imaging.
查看更多>>摘要：? 2022 Elsevier B.V.As deep space exploration is getting further and further away, it is necessary to develop novel packaging shielding material with lightweight and high performance to improve the service life of spacecraft integrated circuits in space radiation environment. However, up to now, constructing a lightweight perovskite/epoxy composite packaging shielding material for spacecraft integrated circuits has not been reported. Hence, in this work, a novel MAPbBr3/epoxy (CH3NH3PbBr3/EP) composite is firstly reported, which shows excellent gamma-rays shielding performance with high linear attenuation coefficient (3.082 cm?1) and high mass attenuation coefficient (2.047 cm2/g). Radiation shielding mechanism indicates that gamma-rays mainly interact with MAPbBr3 dispersed in epoxy. In other words, MAPbBr3 forms a radiation blocking path in epoxy, which significantly attenuates the intensity of incident gamma-rays. In addition, MA+ in MAPbBr3 crystal structure effectively blocks the penetrating behavior of secondary electrons. This work provides a novel strategy for the design and synthesis of high-performance radiation shielding packaging materials.
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