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1.
《Ceramics International》2022,48(11):15268-15273
SiC/SiC mini-composites reinforced with SiC fibers coated with different numbers of ZrSiO4 sublayers prepared via a non-hydrolytic sol-gel process were fabricated. The tensile strength and work of fracture of the prepared SiC/SiC mini-composites were determined, and the relationship between their mechanical properties and fracture morphologies was discussed. The toughening mechanism and the variation tendency of their mechanical properties were further elaborated by analyzing the interfacial debonding morphologies of the SiC/SiC mini-composites with 1 and 4 layers of ZrSiO4 interphase as well as the results of prior studies. A relatively rare phenomenon—the delamination of the multilayer ZrSiO4 interphase in the SiC/SiC mini-composites but not on the SiC fibers—was observed, which clearly demonstrated the weak bonding between the ZrSiO4 sublayers in the SiC/SiC mini-composites. The ZrSiO4 sublayer delamination mechanism was then explained based on the high-magnification morphologies found in and beside the ZrSiO4 interphase. 相似文献
2.
《Ceramics International》2022,48(4):5312-5320
Ce3+ and Pr3+ co?doped Lu3Al5O12 phosphors were synthesized by the sol–gel process, and their crystal structure, photoluminescence (PL) properties, and energy transfer (ET) from the Ce3+ to Pr3+ were studied. The Lu2.94?yAl5O12:0.06Ce3+, yPr3+ phosphors (0.002 ≤ y ≤ 0.008) showed the green?yellow emission from the 2D3/2 → 2F5/2, 7/2 transition of Ce3+ and the red emission at 610 and 637 nm, which were caused by the 1D2→3H4 and 3P0→3H5 transitions of Pr3+, respectively. The optimal concentration of Pr3+ for efficient ET was found to be x = 0.006. The electric quadrupole?quadrupole interaction was responsible for the concentration quenching in the Lu2.94?yAl5O12:0.06Ce3+, yPr3+ phosphors, based on Dexter's theory. The incorporation of Pr3+ for Lu3+ enhanced the red PL intensity in the Lu2.94Al5O12:0.06Ce3+ phosphor. 相似文献
3.
4.
《Ceramics International》2022,48(6):7897-7904
High-performance B4C-PrB6 composites were prepared via hot-pressing sintering with matrix phase B4C and with 2–5 wt% Pr6O11 as additive. The effects of different sintering processes and Pr6O11 content on the microstructure and mechanical properties of the composites were studied in detail. It is found that increasing sintering temperature and pressure will contribute to the densification of B4C-PrB6 composites. Coarse grains are formed in B4C without additives at high temperature conditions, resulting in the decrease of the densification. Pr6O11 can effectively hinder the formation of coarse grains and finally promote the densification of the composites. The main toughening mechanisms of composites was crack deflection. The composites with 4 wt% Pr6O11 prepared at 2050 °C and 25 MPa had the best comprehensive mechanical properties. The relative density, hardness, flexural strength and fracture toughness reached to 98.9%, 37.6 GPa, 339 MPa and 4.4 MP am1/2, respectively. 相似文献
5.
《Ceramics International》2022,48(9):12585-12591
In this study, zinc oxide (ZnO) nanofibers were prepared using the electrospinning method, and the effects of different spinning voltages and annealing temperatures on the fiber structure were tested. La0.8Sr0.2FeO3 (LSFO) perovskite film was prepared by a sol-gel method. Then we dip LSFO on ZnO nanofiber and grow it on the interdigital gold electrode substrate for gas sensors. The results show that the ZnO/LSFO heterostructure gas sensor has a good sensing response to H2S gas and exhibits good gas selectivity. The best gas response is 52.17% under 4 ppm H2S and work temperature 200°C, which has good recovery and reproducibility. 相似文献
6.
Nanosized particles of CoAlxFe2-xO4, where 0?≤?x?≤?2, were synthesized by the sol–gel combustion method and the magnetic properties of these compounds were investigated. According to X-ray diffractograms, the samples are single phase and the crystallite size is between 7 and 25?nm. The room temperature saturation magnetization of the samples was estimated from the cation distribution and ferromagnetic resonance spectra were used to determine the magnetocrystalline anisotropy. The results show that the saturation magnetization and the magnetocrystalline anisotropy vary over a wide range, from maxima of Ms =?0.42?MA/m and K?=?0.39?kJ/m3 for x?=?1.0 to minima of almost zero for x?≈?1.4, a result that could be useful for practical applications of these materials. 相似文献
8.
Kaihui Ma Junyi Deng Gang Wang Qi Zhou Jian Xu 《International Journal of Hydrogen Energy》2021,46(52):26646-26664
Hydrogen (H2) energy is a promising candidate to replace carbon monoxide (CO) as a reductant for iron oxide reduction in revolutionary ironmaking industrial processes, and numerous studies have been conducted to intensively study the utilization and impact of H2 in ironmaking processes. Therefore, this review first collects and compares the H2-assisted reduction mechanism and kinetics. The impacts of H2 on the reduction accompanying behaviors, such as the disintegration, swelling, sticking, softening, and melting of iron ores, are then summarized. Third, the performance of H2 predicted by either mass and heat balance models or numerical simulation models in various ironmaking processes is highlighted. Finally, the different applications of hydrogen-rich materials in blast furnace and non-blast furnace ironmaking processes are further compared to illuminate H2 utilization before our outlook on the use of H2 in the ironmaking industry. 相似文献
9.
Leentje Volker 《Construction Management & Economics》2019,37(1):13-23
In reaction to the recent call for critical debate in the field of construction management research, I argue that we should embrace the richness of adjacent fields of study in order to dynamically develop our own and face the plethora of contemporary societal challenges that exist in our industry. I introduce the concepts of other-than-rational thinking in decision-making and multiplicity in management responses as examples of inspirational sources from social sciences that would contribute to truly understanding the driving forces of construction management processes. I connect these concepts to contemporary studies in construction management and share my experiences with several positive collaborative approaches in conducting construction management research. 相似文献
10.
Mariusz Ciesielski Bohdan Mochnacki 《International Journal of Cast Metals Research》2019,32(4):213-220
The thermal processes proceeding in the casting-mould system are analysed. Solidification process can be described in the different ways. One of them consists in the application of the Fourier–Kirchhoff equation in which the source function controlling the phase change is introduced. In this paper, two approaches to the modelling of pure metals solidification, i.e. the solidification proceeding at the constant temperature and in the artificially introduced interval of temperature are considered. Numerical model used at the stage of computations is constructed using the Control Volume Method in which the principle of conservation of energy (taking also into account the release of latent heat of solidification) is applied to each control volume ensuring the correctness of the model. The use of Voronoi/Thiessen tessellation to the discretization of the casting-mould system can accurately reproduce the shape of each sub-domain. In the final part of the paper, the examples of computations are shown. 相似文献