Egbu, JamesOhodnicki Jr, Paul R.Baltrus, John P.Talaat, Ahmed...
10页
查看更多>>摘要：We report on a systematic investigation of newly developed (Fe70Ni30)(80)Nb4B14Si2 metal amorphous nanocomposites (MANCs) and the factors affecting their surface roughness, including oxide formation and phase evolution during the nanocrystallization process. Analysis of surface roughness using atomic force microscopy (AFM) revealed an average roughness of 9.33 nm after heat treatment compared with as-cast amorphous ribbons, which exhibited a roughness of 4.21 nm. A surface oxide layer thickness has been determined using X-ray photoelectron spectroscopy (XPS). For samples annealed at 400 degrees C for 1 h, 450 degrees C for 1 h, and 550 degrees C for 3 h in air, the average surface oxide layer thickness was determined to be 10.9, 11.7, and 54.4 nm, respectively. It was observed that oxygen is enriched at the outermost surface and decreases rapidly as the XPS sputtering depth increases. Fe-oxide appeared as a predominant metal oxide at the top surface, followed by the presence of Nb oxide. A boron content increase was observed at the interface between the top surface oxide layer and the bulk of the sample. A protective surface oxide layer on FeNi-MANCs, such as observed in this work, can provide sufficient electrical insulation to reduce interlaminate eddy current losses and lower overall losses in magnetic components. (C) 2022 The Author(s). Published by Elsevier B.V.
查看更多>>摘要：Recently, perovskite solar cells (PSCs) have attracted widespread attention due to their outstanding ad-vantages. Hole-transport-material-free carbon-based PSCs (C-PSCs) are some of the most potential devices. However, intrinsically inferior contact at perovskite/carbon interfaces and low conductivity of carbon electrode are restricting the commercial application of C-PSCs. In this study, an N, O co-doped biomass porous composite carbon electrode based on KOH-activated soybean dregs carbon, conductive carbon black and polymethylmethacrylate-N-KSDC-is prepared via a spraying method to efficiently improve per-ovskite/carbon interface qualities as well as enhance the efficiency and stability of C-PSCs. The results showed that the best power conversion efficiencies of N-KSDC-based C-PSCs with an active area of 0.08 and 1 cm(2) were 13.45% and 11.08%, respectively. In addition, unencapsulated PSCs retained 92% of their initial power conversion efficiencies under ambient conditions without intentionally controlling humidity for 62 days. In this study, we propose a feasible and effective strategy to improve the performance and stability of perovskite/carbon interfaces in C-PSCs. (C)& nbsp;2022 Published by Elsevier B.V.
查看更多>>摘要：A series of new transparent and magnetic barium gallogermanate glasses in the system (x) Gd2O3 - (100-x) [20BaO-15Ga(2)O(3)-65GeO(2)] with x = 0,8,14,18,22 and 25 mol% were synthesized. Their thermal, structural and magnetic properties were characterized. Based on the differential scanning calorimetry results, one determined the composition domain exhibiting the highest thermal stability toward crystallization and provided a detailed experimental fabrication method for the production of optical fibers. The local glass structure investigated using combined Raman and Infrared vibrational spectroscopies shows a progressive depolymerization of the 3D glass germanate network accompanied with an increase of non-bridging oxygens when increasing the Gd2O3 content. The incorporation of gadolinium ions tends to extend the IR transmission window. Thanks to the magnetic susceptibility measurements, the paramagnetic behavior was evidenced, and increases with the Gd3+ content. The combination of the optical, thermal and magnetic properties of Gd2O3 gallogermanate glasses as well as their ability to be shaped into optical fibers make them promising materials for their integration in MIR functional optical components. (C) 2022 Published by Elsevier B.V.
Ushakov, M. V.Nithya, V. D.Kumar, N. RajeeshArunkumar, S....
11页
查看更多>>摘要：Magnesium ferrite (MgFe2O4) was synthesized using the solution combustion method. The concentration of the fuel was varied and investigated its effect on spectroscopic, structural and magnetic properties of MgFe2O4 nanoparticles. The XRD pattern showed a decrease in the crystallite size and increase in the lattice strain, dislocation density and specific surface area upon increasing the fuel amount. The shift in the FTIR band (~434 cm-1) corresponds to the Fe-O vibration in the octahedral sites. The values of HC decreased while Mr values increased continuously with the increase of the fuel concentration. The Mossbauer spectra of MgFe2O4 nanoparticles measured with a high velocity resolution demonstrated a large number of magnetic sextets assigned to the tetrahedral (A) and octahedral [B] sites. These magnetic sextets were considered as a result of different Fe3+ local microenvironments depending on Mg2+ cations distributions among the neighboring (A) and [B] sites. The calculations of binomial distribution of the probabilities of the numbers of Mg2+ cations within the sphere of 3.7 A around Fe3+ cations in both (A) and [B] sites demonstrated distributions of different probabilities for these sites in agreement with the Mossbauer spectra fits. The numbers of magnetic sextets and their hyperfine parameters assigned to the (A) and [B] sites were found slightly varied for MgFe2O4 nanoparticles prepared with different fuel concentrations.(c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The design and fabrication of advanced carbon materials is highly important for potassium ion batteries. In this paper, Fe3C nanoparticles embedded in N-doped carbon nanotubes/porous carbon (Fe3C@N-CNPC) 3D materials were synthesized by pyrolysis of N-doped distilled grains in the presence of FeCl3/ZnCl2 activators. It was demonstrated that the FeCl3/ZnCl2 activators played an important role in the formation of Fe3C@ N-CNPC 3D materials. On the one hand, the activator endowed the carbonaceous materials with a high proportion of micropores and large surface area. On the other hand, Fe nanoparticles generated by decomposition of FeCl3 catalyzed the growth of intertwined carbon nanotubes on porous carbon, yielding Fe3C@N-CNPC 3D materials with abundant porous structure and a high degree of graphitization. The asprepared Fe3C@N-CNPC were used as anode materials for potassium ion batteries. Due to the synergistic effect of N-doping, superstructure, and large surface area, the Fe3C@N-CNPC based potassium ion batteries exhibited remarkable potassium storage capacity (273 mAh g-1 at 100 mA g-1) and excellent cycle stability (94% capacity retention at 100 mA g-1 after 570 cycles). This novel carbon material with low cost and ease preparation is of great significance for the application of potassium ion batteries. Meanwhile, our strategy also provides a reference idea for the resource utilization of the distilled grains waste. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Despite high entropy alloys (HEAs), phase formation rules as a simple method have been seldom used to predict the solid solution phases in light high entropy alloys (LHEAs). Some terms and thermodynamic based parameters are calculated via programing and all 4833 possible quintuple alloys out of proper elements are extracted and categorized in seven alloy groups and fifteen alloy systems with a density less than or equal to 5 g cm(-3) defined for LHEAs in this research. As expected, most alloys had low-density elements like Li, Mg, Al, and Ti in their chemical composition. Al14Li11Mg35Ti15Zr25 alloy was identified as the lightest alloy (3.36 g cm(-3)). Various alloys can be obtained and designed with optimizing values for the atomic size difference, electronegativity difference, and other respective terms. All alloy groups and systems are discussed and limitations for alloying methods are described. Al19Li7Mg6Ti35Nb33 LHEA was chosen as a candidate alloy to fabricate by melting and characterization of the as-cast alloy showed the formation of a high hardness single-phase BCC solid solution structure. Acceptable uniformity in the chemical composition of the alloy with a density of 5.31 g cm(-3) confirms the relative reliability of phase formation rules. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In2Se3 have attracted researcher's attention due to its potential optoelectronic and memory device applications, having various polymorphs with few of them having layered structure. There exists a non-layered phase with vacancy ordered in screw form known as gamma-In2Se3, whose properties are found to get affected majorly by the presence of defects. Here, the first principles calculations based on the density functional theory are performed to study the intrinsic point defects in defect wurtzite structure of gamma-In2Se3 using GGAPBE approximations. Thermodynamic charge transitions based on the formation energy of the defects are determined for all native defects, VIn, VSe, Ini, Sei, SeIn, InSe, under In-rich and Se-rich experimental growth conditions. The charge transition remains the same but transition energies differ for possible coordination of Se vacancies, whereas the charge transition as well as transition energy vary for different coordination sites of In vacancies. The In interstitial, Ini is the most favourable defect site under In-rich conditions whereas SeIn at the VBM and VIn1 near CBM are dominating under Se-rich conditions. The origin of n-type conductivity of gamma-In2Se3 is found to be the presence of Ini interstitials and InSe antisite in the defect wurtzite gamma-In2Se3. Further, the films grown using PLD shows an n-type conductivity under In-rich conditions leading to a good performance with photo responsivity and specific detectivity of 5.22 x 102 A/W and 5.08 x 1013 Jones. The understanding of these vacancies determines their thermodynamic behaviour which can help for the controlled growth of gamma-In2Se3 which leads to better device performance. (c) 2022 Elsevier B.V. All rights reserved.
Moghaddam, Ahmad OstovariMikhailov, DmitryFereidonnejad, RaheleShaburova, Nataliya...
8页
查看更多>>摘要：High entropy intermetallic compounds (HEICs) are the most recent poster child of high entropy materials (HEMs), which provide a new paradigm to develop novel materials with potentially unusual properties. Here, FeNiCrV-TiNb, (Ni1/5-Co1/5-Fe1/5-Cu1/5-Mn1/5)3(Al1/2-Ti1/2), and (Fe1/5Ni1/5Co1/5Cr1/5Mn1/5)(Mo1/2Cr1/2) HEICs were fabricated by melting technique. The as-cast FeNiCrV-TiNb exhibited C14 Laves structure with varying chemical composition, which probably consists of two sub-lattices with slightly different lattice parameters. (Fe0.2Ni0.2Co0.2Cr0.2Mn0.2)(Mo0.5Cr0.5) crystalized into a single sigma-phase and revealed a homogenous microstructure with negligible segregation. A two-phase B2 +D03 structure with clear segregation of Cu, Fe, and Mn was obtained for (Ni0.2Co0.2Fe0.2Cu0.2Mn0.2)3(Al0.5Ti0.5) HEIC. The microhardness values were 915 Hv, 593 Hv, and 1051 Hv for FeNiCrV-TiNb, (Ni0.2Co0.2Fe0.2Cu0.2Mn0.2)3(Al0.5Ti0.5) and (Fe0.2Ni0.2Co0.2Cr0.2Mn0.2)(Mo0.5Cr0.5) HEICs, respectively. The last one is the highest value reported for an as-cast metallic HEM. (Ni0.2Co0.2Fe0.2Cu0.2Mn0.2)3(Al0.5Ti0.5) exhibited a soft magnetic behavior with a saturation magnetization of 27.7 emu/g and coercivity of ~ 311 Oe at 300 K, while FeNiCrV-TiNb and (Fe0.2Ni0.2Co0.2Cr0.2Mn0.2)(Mo0.5Cr0.5) showed an approximately linear dependency of magnetization vs. magnetic field. Finally, two modified parameters are introduced to expedite the discovery of new singlephase HEICs.
查看更多>>摘要：Antimony selenide (Sb2Se3) is a very handy light-absorbing material in photochemical devices based on TiO2 nanotube arrays (TNT), but it has some problems with anisotropy and agglomeration. Large particles of antimony selenide instead impede photon transport and are susceptible to photocorrosion instability, making it crucial to develop a strategy for the directional growth of rod-shaped Sb2Se3 arrays. Herein, we successfully achieved the deposition of Sb2Se3 inside the tube of TNT by pulsed electrodeposition strategy to obtain the oriented Sb2Se3 nanorod arrays for efficient photoelectron transport. The conductive atomic force microscopy indicates the enhanced electron transfer performance. The UV spectral conclusion shows that the deposition of rod-shaped Sb2Se3 enhances the UV-vis diffuse absorption of TiO2, meanwhile, TNT acts as a shell to protect antimony selenide and effectively prevents its photocorrosion phenomenon. Therefore, the photocurrent density of TNT/Sb2Se3 NRs is 6.79 times as that of bare TNT. The Pt/TNT/Sb2Se3 NRs electrode exhibits a photocurrent density of 2.6 mA cm(-2) (-0.2 V RHE) and considerable hydrogen evolution per-formance. In addition, the Surface-Enhanced Raman effect (SERS) originated from this Sb2Se3 array, is first observed, which is expected to reduce the cost of SERS technology. (C)& nbsp;2022 Published by Elsevier B.V.
查看更多>>摘要：The SiBCN composite fibers with strong electromagnetic wave (EMW) absorption performance were successfully prepared via polymer-derived ceramics (PDCs) and electrospinning methods at relatively lower preparation temperature. The results showed that the in-situ generated free carbon which existed in the matrix in the form of simple substance and was characterized by low crystallinity. The graphite carbon improved the dielectric loss and properties of SiBCN composite fibers. In particular for the SiBCN composite fibers pyrolyzed at 1300 degrees C, the in-situ generated nano beta-SiC crystallization increased the EMW absorption performance significantly. The minimum reflection loss (RLmin) of the SiBCN-3 reached - 54.91 dB at 2.35 mm and the effective absorption band (EAB, RL <= -10 dB) reached 4.72 GHz (13.28-18 GHz, 1.75 mm). Hence, the SiBCN fibers prepared at relatively lower temperature give good absorption performance and predict a broader application prospect in the field of EMW absorption materials.(c) 2022 Elsevier B.V. All rights reserved.
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