The mass spectra of both positive and negative charged Ta-containing ions from laser ablatiou of Ta2O5 were measured using a time-of-flight mass spectrometer. Formation of iomc Ta-containing oxides such as TaO and TaO...The mass spectra of both positive and negative charged Ta-containing ions from laser ablatiou of Ta2O5 were measured using a time-of-flight mass spectrometer. Formation of iomc Ta-containing oxides such as TaO and TaO from Ta2O5 ablation in ambient O2 were observed for the first time. The influence of ambient O2 pressure on the intensities of ablated Ta-containing ions has also been studied. It is found that the subsequent oxidation reactions were involved in the ablation of Ta2O5 at different O2 pressure. The enthalpies of possible okidation reactions were theoretically calculated, and the possible formation reastions of the ionic Ta-contauing oxides are discussed.展开更多
Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed...Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed oxides. The degradation mechanisms of Ti/IrO_2+ Ta_2 O_5 and Ti/IrO_2 +Ta_2 O_5 +SnO+2 anodes were different. It was shown from the observation of scanning electron microscopy (SEM) and the electrochcmical measurement that, the deactivation of Ti/IrO_2 + Ta_2 O_5 anode was due to the build-up of an organic film on surface. The growth of the covered film on surface was restricted by addition of SnO_2, which resulted in increasing of the service life of anodes. The over-potential for oxygen evolution on Ti/IrO_2 +Ta_2 O_5 electrode increased after doping SnO_2, and the intermediate products of PSA building-up on the surface was much more rapidly oxidized. Meanwhile, a certain part of the surface oxide deposit entered into the solution leading to loss of oxides, which resulted in degradation of Ti/IroO_2 + Ta_2 O_5 anode containing SnO_2 component.展开更多
A potential orthorhombic phase of Ta_(2)O_(5),designated as Y-Ta_(2)O_(5),is predicted under high-pressure conditions using density functional theory(DFT)combined with structural search algorithms.This phase,containin...A potential orthorhombic phase of Ta_(2)O_(5),designated as Y-Ta_(2)O_(5),is predicted under high-pressure conditions using density functional theory(DFT)combined with structural search algorithms.This phase,containing four formula units per unit cell(Z=4),exhibits the highest Ta-O coordination numbers reported to date.Y-Ta_(2)O_(5)is identified as the most energetically stable form of Ta_(2)O_(5)within the pressure range of approximately 70 GPa to at least 200 GPa.Both standard DFT-GGA and higher-accuracy GW calculations indicate that Y-Ta_(2)O_(5)is a wide-bandgap semiconductor with a direct bandgap.Furthermore,nuclear quantum effects(NQEs)introduce nontrivial corrections to external pressure at fixed volumes,underscoring their significance in high-pressure phase stability analyses.展开更多
We employed Monte Carlo simulations via Geant4 to model the interactions of^(60)Co gamma rays(1.25 MeV),electrons(0.1-10 MeV),and protons(0.5-10 MeV)with Ta_(2)O_(5)optical coatings.By analyzing secondary electron gen...We employed Monte Carlo simulations via Geant4 to model the interactions of^(60)Co gamma rays(1.25 MeV),electrons(0.1-10 MeV),and protons(0.5-10 MeV)with Ta_(2)O_(5)optical coatings.By analyzing secondary electron generation and energy deposition,we found that 1.0 MeV electrons and protons produce 67.5 and 67 secondary electrons per particle,respectively,compared to 116 from 1.25 MeV gamma rays in thick targets.Boltzmann-function fitting revealed depth-dependent ionization equivalence:0.582 gamma photons match the secondary electron yield of a 1.0 MeV electron,and 0.577 gamma photons match a 1.0 MeV proton.These results establish a framework to convert ground-based gamma-ray test data to space environment scenarios,accounting for critical differences in penetration depth-protons deposit energy within 10μm(coating layers),while gamma rays penetrate>100 mm into substrates.This provides a theoretical basis for evaluating radiation effects using existing^(60)Co facilities,enabling reliable predictions of optical component durability in complex space environments.展开更多
文摘The mass spectra of both positive and negative charged Ta-containing ions from laser ablatiou of Ta2O5 were measured using a time-of-flight mass spectrometer. Formation of iomc Ta-containing oxides such as TaO and TaO from Ta2O5 ablation in ambient O2 were observed for the first time. The influence of ambient O2 pressure on the intensities of ablated Ta-containing ions has also been studied. It is found that the subsequent oxidation reactions were involved in the ablation of Ta2O5 at different O2 pressure. The enthalpies of possible okidation reactions were theoretically calculated, and the possible formation reastions of the ionic Ta-contauing oxides are discussed.
文摘Service life of two different oxide anodes in phenolsulfonic acid (PSA) solution was investigated by accelerated electrolysis. The durability of Ti/IrO_2+Ta_2 O_5 anode increased by the addition of SnO_2 in the mixed oxides. The degradation mechanisms of Ti/IrO_2+ Ta_2 O_5 and Ti/IrO_2 +Ta_2 O_5 +SnO+2 anodes were different. It was shown from the observation of scanning electron microscopy (SEM) and the electrochcmical measurement that, the deactivation of Ti/IrO_2 + Ta_2 O_5 anode was due to the build-up of an organic film on surface. The growth of the covered film on surface was restricted by addition of SnO_2, which resulted in increasing of the service life of anodes. The over-potential for oxygen evolution on Ti/IrO_2 +Ta_2 O_5 electrode increased after doping SnO_2, and the intermediate products of PSA building-up on the surface was much more rapidly oxidized. Meanwhile, a certain part of the surface oxide deposit entered into the solution leading to loss of oxides, which resulted in degradation of Ti/IroO_2 + Ta_2 O_5 anode containing SnO_2 component.
基金supported by the National Natural Science Foundation of China(Grant Nos.12074382,11474285,and 12464012)the crew of the Center for Computational Materials Science,Institute for Materials Research of Tohoku University,and the supercomputer resources through the HPCI System Research Project(hp200246).
文摘A potential orthorhombic phase of Ta_(2)O_(5),designated as Y-Ta_(2)O_(5),is predicted under high-pressure conditions using density functional theory(DFT)combined with structural search algorithms.This phase,containing four formula units per unit cell(Z=4),exhibits the highest Ta-O coordination numbers reported to date.Y-Ta_(2)O_(5)is identified as the most energetically stable form of Ta_(2)O_(5)within the pressure range of approximately 70 GPa to at least 200 GPa.Both standard DFT-GGA and higher-accuracy GW calculations indicate that Y-Ta_(2)O_(5)is a wide-bandgap semiconductor with a direct bandgap.Furthermore,nuclear quantum effects(NQEs)introduce nontrivial corrections to external pressure at fixed volumes,underscoring their significance in high-pressure phase stability analyses.
基金Funded by the Zibo Key Research and Development Project(No.2020XCCG0106)the Zibo Key Research and Development Project(No.2021SNPT0004)the Opening Project of Glass-based Functional Material Technology Innovation Center(No.GFMTIC2025C01)。
文摘We employed Monte Carlo simulations via Geant4 to model the interactions of^(60)Co gamma rays(1.25 MeV),electrons(0.1-10 MeV),and protons(0.5-10 MeV)with Ta_(2)O_(5)optical coatings.By analyzing secondary electron generation and energy deposition,we found that 1.0 MeV electrons and protons produce 67.5 and 67 secondary electrons per particle,respectively,compared to 116 from 1.25 MeV gamma rays in thick targets.Boltzmann-function fitting revealed depth-dependent ionization equivalence:0.582 gamma photons match the secondary electron yield of a 1.0 MeV electron,and 0.577 gamma photons match a 1.0 MeV proton.These results establish a framework to convert ground-based gamma-ray test data to space environment scenarios,accounting for critical differences in penetration depth-protons deposit energy within 10μm(coating layers),while gamma rays penetrate>100 mm into substrates.This provides a theoretical basis for evaluating radiation effects using existing^(60)Co facilities,enabling reliable predictions of optical component durability in complex space environments.
