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Neutron irradiation causes embrittlement of reactor pressure vessel (RPV) steels. Post-irradiation annealing is capable of partly or fully restoring the unembrittled condition. While annealing at high temperatures (e.g., 475°C) was successfully applied to extend the lifetime of operating VVER-440 reactors, the benefit of annealing at lower temperatures (e.g., 343°C-the maximum to which the primary cooling water can be heated) is a matter of debate. In this study, neutron-irradiated VVER-440 RPV base metal and weld were exposed to isothermal annealing at 343°C up to 2,000 h. Given the limited amount of material, the degree of recovery was estimated in terms of Vickers hardness, the ductile-brittle transition temperature derived from small punch tests, and the master curve reference temperature derived from fracture mechanics tests of mini samples. For the base metal, small-angle neutron scattering was applied to underpin the findings at the nm-scale. We have found significant partial recovery in both materials after annealing for 300 h or longer. The variations of the degree of recovery are critically discussed and put into the context of wet annealing. [ABSTRACT FROM AUTHOR]

Neutron irradiation causes embrittlement of reactor pressure vessel (RPV) steels. Post-irradiation annealing is capable of partly or fully restoring the unembrittled condition. While annealing at high temperatures (e.g., 475°C) was successfully applied to extend the lifetime of operating VVER-440 reactors, the benefit of annealing at lower temperatures (e.g., 343°C–the maximum to which the primary cooling water can be heated) is a matter of debate. In this study, neutron-irradiated VVER-440 RPV base metal and weld were exposed to isothermal annealing at 343°C up to 2,000 h. Given the limited amount of material, the degree of recovery was estimated in terms of Vickers hardness, the ductile-brittle transition temperature derived from small punch tests, and the master curve reference temperature derived from fracture mechanics tests of mini samples. For the base metal, small-angle neutron scattering was applied to underpin the findings at the nm-scale. We have found significant partial recovery in both materials after annealing for 300 h or longer. The variations of the degree of recovery are critically discussed and put into the context of wet annealing.

In this work, we show that utilizing a low temperature wet annealing ambient can greatly improve the electrical characteristics of a solution processed oxide thin‐film transistor (TFT). Compared to atmospheric annealed devices (∼0.74 cm2/Vs), characteristics such as mobility can be 4 times higher for the wet annealed devices (∼2.99 cm2/Vs). [ABSTRACT FROM AUTHOR]

Hydrogels are widely used in tissue engineering, soft robots, wearable electronics, etc. However, it remains a great challenge to develop hydrogels possessing simultaneously high strength, large stretchability, great fracture energy, and good fatigue threshold to suit different applications. Herein, a novel solvent-exchange-assisted wet-annealing strategy is proposed to prepare high performance poly(vinyl alcohol) hydrogels by extensively tuning the macromolecular chain movement and optimizing the polymer network. The reinforcing and toughening mechanisms are found to be "macromolecule crystallization and entanglement". These hydrogels have large tensile strengths up to 11.19 ± 0.27 MPa and extremely high fracture strains of 1879 ± 10%. In addition, the fracture energy and fatigue threshold can reach as high as 25.39 ± 6.64 kJ m -2 and ≈1233 J m -2 , respectively. These superb mechanical properties compare favorably to those of other tough hydrogels, organogels, and even natural tendons and synthetic rubbers. This work provides a new and effective method to fabricate superstrong, tough, stretchable, and anti-fatigue hydrogels with potential applications in artificial tendons and ligaments., (© 2023 Wiley-VCH GmbH.)

We performed constant positive gate bias stress tests on sputter-deposited amorphous In-Ga-Zn-O (a-IGZO) thin-film transistors (TFTs) fabricated with various annealing conditions. We found that the time evolution of threshold voltage shift (ΔVth ) during the stress test exhibits two different behaviors; a power function type and a logarithmic function type. Combining with thermal desorption spectroscopy (TDS), we found that the ΔVth type changes fromthe log-function type to the power-function type as H2 desorption increases. The power-function type is attributed to a H-diffusion limited process. As for the log-function type, the magnitude of ΔVthhas correlation with the hysteresis width in a first transfer curve and the desorption amount of H2O and O2species between 200°C-300°C. Hence, it is considered that the traps causing the log-function type ΔVthare meta-stable states related to O- and/or OH-related weak bonds. [ABSTRACT FROM AUTHOR]

Origin of constant positive gate bias stress instability in amorphous In-Ga–Zn-O thin-film transistor is studied. Threshold voltage shift ( \(\Delta \) V \(_{{{\rm th}}}\) ) during the stress test exhibits two different behaviors: 1) a power function-type and 2) a logarithmic function-type depending on thermal treatment atmosphere and temperature. Thermal desorption spectroscopy indicated that the \(\Delta \) V \(_{\rm th}\) behavior changes from the log-function type to the power-function type as the amount of H2 desorption increases. Furthermore, the recovery behavior of \(\Delta \) V \(_{{{\rm th }}}\) was not affected by gate bias. These results are explained by a diffusion-limited process of neutral hydrogen, which occurs within 2 nm in the vicinity of the channel-insulator interface. [ABSTRACT FROM PUBLISHER]

Indium-doped zinc oxide (In-doped ZnO) thin films were deposited on silicon substrates by radio frequency magnetron co-sputtering of ZnO and In targets. The effects of wet annealing at various temperatures on the films were investigated. All the films had a hexagonal wurtzite structure with preferred c-axis orientations. The crystal structure of the films was improved as the wet annealing temperature was increased to 800°C and then deteriorated at 900°C due to the presence of cracks and porosity. The surface morphologies of the films changed significantly as the wet annealing temperature reached above 800°C. Besides that, strong emission at near-band-edge of ZnO and green emission were observed as the annealing temperature increased. Overall, In-doped ZnO thin film annealed at 800°C has the best structural and optical properties. [ABSTRACT FROM AUTHOR]