查看更多>>摘要：? 2022 Elsevier B.V.To improve the service performance of Cu/W plasma-facing components (PFCs), the influence of the Cu/W interfacial structure on the resistance against harmful He atoms, including the He weakening effect and He atom intrusion, was investigated using density functional theory (DFT) calculations. The Cu(100)/W(100), Cu(110)/W(110), and Cu(111)/W(111) were selected as the representative Cu/W interfacial structures. The results show that He atom intrusion at the Cu/W interface weakens the interfacial Cu–W ionic bonding strength and the covalent bonding strength simultaneously, causing a decrease in the Cu/W interface bonding property (He weakening effect). The Cu(111)/W(111) interfacial structure shows the largest resistance to the He weakening effect owing to the minimal reduction of the interfacial work of adhesion ~0.45 J/m2; this is attributed to the lesser weakening degree of the Cu–W ionic bonding strength. Moreover, when He atoms diffuse along the Cu/W interface, the interactions between the He atoms at the saddle point and the surrounding Cu and W atoms on the Cu(111)/W(111) interfacial structure are the strongest. The resulting highest energy barrier of ~6.84 eV and the resulting low diffusion coefficient indicate that the Cu(111)/W(111) interfacial structure also has the strongest hindrance capacity against He atom intrusion. Therefore, Cu(111)/W(111) is the most promising Cu/W interfacial structure, which can significantly improve the service performance of the Cu/W PFC.
查看更多>>摘要：? 2022 Elsevier B.V.The (NH4)2Co2V10O28·16H2O/(NH4)2V10O25·8H2O (NCVO-NVO)-based heterostructure nanorods with a length that lies within the range of 800–1200 nm and a width of 150 nm was fabricated by enforcing a simple hydrothermal method. In this structure, the ammonium ion and water enlarge the interlayer distance of the layered vanadium-oxide and at the same time promote the insertion/extraction of Zn2+ into the layered structure without imposing any volume change. In addition, the internal electric field built at the heterointerface of the NCVO-NVO-based heterostructure can facilitate the Zn2+ diffusion and improve the reaction kinetics. On top of that, when is exploited as cathode material in aqueous Zn-ion batteries (AZIBs), the NCVO-NVO electrode presents a relatively high discharge capacity (367.7 mAh g?1 at 0.1 A g?1) in combination with an excellent cycling performance (201.3 mAh g?1 after 1000 cycles at 1.0 A g?1 with an enhanced capacity retention of 82.1%). The enormous potential of the fabricated vanadium-oxide heterostructure cathode is indicated in this work to develop for AZIBs with improved properties.
查看更多>>摘要：? 2022 Elsevier B.V.Developing electromagnetic wave (EMW) absorbing materials with reasonable structure and composition is of great significance. In this work, the porous mangosteen shells-derived carbon embedded with globular MnO2 nanoflowers (MnO2@PMSC) were fabricated via two-step carbonization and subsequent hydrothermal synthesis. The biomass-based carbon with highly opened hierarchical porous structures provides abundant in-situ growth points for globular MnO2 nanoflowers, ensuring that they could nucleate in situ and grow inside the carbon walls. It is worth noting that the EMW absorption properties of the absorber can be efficiently enhanced by tuning the contents of globular MnO2 nanoflowers. The as-synthesized optimal sample (MnO2@PMSC-2) exhibits superior EMW absorption performances with the minimum reflection loss (RLmin) value of ?54.61 dB and wide effective absorption bandwidth (EAB) of 4.10 GHz at 1.80 mm. The excellent EMW absorption performance is attributed to the multiple reflection and scattering caused by the hierarchical porous structures of the biomass carbon and the flower–like structure of MnO2, strong polarization effects between MnO2 and carbon walls, as well as the good impedance matching condition achieved by the strong synergy between the two components. These results indicated that MnO2@PMSC-2 is a potential electromagnetic wave absorber.
查看更多>>摘要：? 2022Here, we have approached to discover new aluminum (Al) alloys with the assistance of artificial intelligence (A.I.) for the enhanced mechanical property. A high prediction rate of 7xxx series Al alloy was achieved via the Bayesian hyperparameter optimization algorithm. With the guide of A.I.-based recommendation algorithm, new Al alloys were designed that had an excellent combination of strength and ductility with a yield strength (YS) of 712 MPa and elongation (EL) of 19%, exhibiting a homogeneous distribution of nanoscale precipitates hindering dislocation movement during deformation. Adding Mg and Cu was found to be the critical factor that decides the relative ratio of strength and EL. We also demonstrate an explainable A.I. (XAI) system that reveals the relationship between input and output parameters. Our A.I. assistant system can accelerate the search for high-strength Al alloys for both experts and non-experts in the field of Al alloy design.
查看更多>>摘要：? 2022 Elsevier B.V.Aqueous zinc-ion batteries (ZIBs) have provided new opportunities and challenges to the energy storage market due to their low price, high safety and environmentally friendly. Among the cathode materials of ZIBs, MnO2 appears to one of the most promising cathode for ZIBs owing to its high theoretical capacitance, abundant reserves, non-toxicity, and low cost. However, the poor cycling stability and rate performance have been the bottle-neck of MnO2 due to the slow electrochemical kinetics and severe structural damage during cyclic process. Herein, a new strategy is proposed to optimize the cycling stability and rate performance of the pristine MnO2 by a simple surface modification of manganese hexacyanoferrate (MnHCF). The anchored MnHCFs not only relieves the manganese dissolution during the continuous charge and discharge, but also introduces oxygen defects boosting the electrochemical kinetics of MnO2. The as prepared composite delivers a reversible specific capacity of 287 mA h g?1 at 0.1 A g?1 and maintains 87.1% of its initial capacity after 70 cycles.
查看更多>>摘要：? 2022 Elsevier B.V.0.1%, 0.5%, and 1% Er:Bi4Ge3O12 (BGO) single crystals were grown by the floating zone method, and the structural, optical, and scintillation properties were investigated. From the X-ray diffraction analyses, all the obtained crystals were confirmed to be in the single phase of BGO. The crystals exhibited photoluminescence and scintillation due to the 4f–4f transitions of Er3+ peaking at ~550 and 1540 nm as well as an emission band due to the 3P1–1S0 transitions of Bi3+ across 400–600 nm. The photoluminescence quantum yields of the NIR emission (1429–1677 nm) were 50.6%, 85.8%, and 69.0% for the 0.1%, 0.5%, and 1% Er-doped crystals, respectively. The scintillation decay curves were measured in the spectral range from UV to NIR, and the decay time constants of the visible–NIR luminescence were confirmed to be consistent with the known values of Er3+. The afterglow level at 20 ms after X-ray irradiation was 12.0–25.4 ppm, which is similar to the value of Nd:BGO. All the crystals showed a good linearity between the near-infrared luminescence intensity and X-ray exposure dose rate, and the lowest detectable dose rate was 0.006 Gy/h in all the crystals.
查看更多>>摘要：? 2022 Elsevier B.V.Developing cost-effective thermoelectric (TE) materials that do not rely on toxic and expensive elements is crucial to widespread use in practical applications. Earth-abundant Fe3Al2Si3-based thermoelectric materials exhibit moderate thermoelectric properties near room temperature. Hence, improving the thermoelectric properties of these materials may lead to practical applications. In this study, we investigated the microstructural factors controlling the electrical conductivity (σ) in p-type Fe3Al2Si3-based thermoelectric (FAST) material to find ways to improve the TE performance. The σ of a large-grained stoichiometric τ1-Fe3Al2Si3 compound is low, ~1 × 104 Ω–1 m–1 at room temperature, whereas a high σ of ~6.7 × 104 Ω–1 m–1 is obtained in Al-lean alloys. Microstructure observation revealed that the formation of a composite structure consisting of FeSi (?-phase) precipitates dispersed in the τ1-matrix results in an increase in σ while maintaining thermal conductivity and sufficiently high Seebeck coefficient to improve the power factor. We found that the Ohmic-contacted ?-phase can modify the surrounding τ1-matrix to an Al-lean τ1-phase, which contributes to the carrier concentration increment and brings six times the enhancement of σ. This led to a power factor of ~880 μW m–1 K–2, more than three times larger than that of the single-phase compound (~250 μW m–1 K–2), the highest for the earth-abundant Fe–Al–Si system. This work demonstrates that the control of τ1-Fe3Al2Si3/?-FeSi composite microstructure is critical to developing a higher power factor in p-type FAST materials.
查看更多>>摘要：? 2022 Elsevier B.V.Αn isotype heterojunction n+-ZnO/n-Si photodetector is developed, demonstrating wavelength-selective or broadband operation, depending on the applied bias voltage. Additionally, at self-powered (zero bias) operation, it distinguishes between UV, visible, and near IR (NIR) photons by polarity control of the photocurrent. The photodetector is developed by atomic layer deposition (ALD) of ZnO on n-Si, followed by electric contact deposition and annealing. Photoluminescence measurements reveal high optical quality and improved crystallinity of annealed ZnO on silicon. Photocurrent measurements as a function of illumination wavelength and bias voltage show small negative values in the UV–visible spectral range at zero and positive bias voltage and high positive values in the NIR spectral range. For these measurements, we consider the electric contact to ZnO as the anode and the electric contact to silicon as the cathode. At negative bias voltage, the device shows broadband operation with high photocurrent values across the UV–vis-NIR.
查看更多>>摘要：? 2022 Elsevier B.V.The Rietveld refinement of the polycrystalline powders of 1% Fe and Mn-doped (Na0.5Bi0.5)0.94Ba0.06Ti0.98V0.02O3 at the Ti-site confirmed a single rhombohedral (R3c) phase. The bandgap, (Eg) was affected by the anti-phase octahedral tilt angle and the spin-orbit splitting energy of Ti4+2p3/2 and Ti4+2p1/2 states. The decrease in Bi loss and increase in the binding energy of Ba due to Fe/Mn doping has been correlated to the strengthening of Bi-O and Ba-O bonds which was revealed from the XPS studies thereby further related to the average A-O bond length from structural studies. Hence, a reduction of oxygen vacancy (VO) for the doped samples has been justified. A significant improvement of the dielectric constant, relaxation time (τ0), and the decrease in conductivity due to doping was revealed from the frequency-dependent (10 Hz-1 MHz) dielectric measurement study. The conduction and relaxation process are dominated by the short-range movement of defects. The activation energy (Ea ~1 eV) revealed that there is a presence of double-ionized VOs. The ECE study showed a significant enhancement of the changes in entropy, ΔS, and the adiabatic temperature difference, ΔT, due to doping, with ΔT being highest in the Fe-doped sample. Such improvement of dielectric and ECE properties was confirmed due to the reduction of the mobility of oxygen vacancy because of the formation(MnTi′′?Vo??)/(MnTi′?Vo??)? and FeTi′′?Vo??/(FeTi′?Vo??)? defect dipoles.
查看更多>>摘要：? 2022 Elsevier B.V.In this study, the α-Ag2WO4 samples were successfully synthesized combined two methods, co-precipitation and microwave-assisted hydrothermal. Later, two different irradiation processes: electron beam and femtosecond laser are applied. Unit cell changes were shown by X-ray measurements and Rietveld analysis and compared with the results obtained for first-principle calculations. The formation of oxygen vacancies on the surface of the particles after the irradiation process was revealed by XPS measurements. Electron beam and femtosecond laser irradiations were found to cause expansion of the unit cell, form oxygen vacancies on the surface, change the angle and distance between O[sbnd]Ag and O[sbnd]W bonds, and modify the particle morphology to rod-, cube- and sphere-like. The XANES measurements confirm that the local order of the W atoms is maintained along the different irradiation processes. Based on the theoretical analysis of surfaces investigation and Wulff construction, the contribution of (010) and (101) surfaces at the emission centers in 550 and 733 nm associated with the PL spectrum of α–Ag2WO4, was established
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