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141.
142.
《Measurement》2014
The thin epoxy film with micro-scale speckle pattern as a digital image correlation (DIC) deformation sensor has been fabricated or transferred on the surface of sample in the previous study. When the thickness of the film cannot be ignored, it may have an influence on the validity of measurement results. And thus, the influence of the thin epoxy film on mechanical properties of substrates should be investigated. In this study, the mechanical behavior of thin film itself and surface strain of composite structure of thin film and substrate were measured using micro digital image correlation (MDIC) method. And theoretical and simulative results were also analyzed. From the comparison analysis of theoretical, simulative and experimental results, it is concluded that when the ratios of Young’s modulus and thickness between the film and substrate are smaller than 13 and 0.5 respectively, the influence from the thin film can be ignored, and thin epoxy film as DIC sensor can be used to measure the deformation of substrate. 相似文献
143.
《Calphad》2018
Rare earth (RE) elements especially Yb, La and Ce have been frequently doped to Bi-Te alloys to improve thermoelectric performance. Three isothermal sections: Bi-Te-Yb at 573 K, Bi-Te-La and Bi-Te-Ce at 673 K were partly established by means of electron probe micro-analysis (EPMA) and powder X-ray diffractometry (XRD). The determined maximum solubilities of RE elements in Bi-Te alloys are very small and that of Yb reached the maximum about 0.3 at% at 573 K. Both LaTe2 and CeTe2 can dissolve a large amount of Bi, about 10 and 13 at% at 673 K, respectively. No ternary compound has been confirmed. 相似文献
144.
《Journal of the European Ceramic Society》2017,37(5):1993-2000
Silicon oxycarbide monoliths of different pore size distribution were fabricated by freeze-casting. The samples revealed a lamellar pore structure with an axial anisotropy. To evaluate the capillary transport abilities we performed wicking experiments. The sample weight measurement method was applied during the imbibition. The samples show deviations in permeability from 10% to 49% at different sample orientations that quantifies the impact of the anisotropy in the axial direction. The deviations were larger for the samples with smaller pore size. For these samples we also observed larger differences in the wicking behaviour. The samples with bigger pore size demonstrated higher permeability and faster wicking. Imbibition results at both sample orientations showed a good agreement with a prediction via the Lucas–Washburn equation with gravity effects. We demonstrate hereby, that our approach of macroscopic modelling predicts wicking behaviour in anisotropic structures reasonably well, providing a simple tool for further porous material investigations. 相似文献
145.
Fabrication of ZnS/C microsphere composites with enhanced electromagnetic wave absorption properties
Xing Honglong Wang Yin Bai Linghan Ji Xiaoli Yang Ping 《Journal of Materials Science: Materials in Electronics》2022,33(25):20021-20034
Journal of Materials Science: Materials in Electronics - For electromagnetic wave-absorbing materials, organic-derived carbon materials and metal sulfides are highly preferred. In this paper, ZnS/C... 相似文献
146.
《Soils and Foundations》2022,62(1):101089
In recent years, the mechanical properties of frozen soils under complex stress states have attracted significant attention; however, limited by the test apparatus, true triaxial tests on frozen soils have rarely been conducted. To study the strength and deformation properties of frozen sand under a true triaxial stress state, a novel frozen soil testing system, i.e., a true triaxial apparatus, was developed. The apparatus is mainly composed of a temperature control system, a servo host system, a hydraulic servo loading system, and a digital control system. Several true triaxial tests were conducted at a constant minor principal stress (σ3) and constant intermediate principal stress ratio (b) to study the effect of intermediate principal stress (σ2) on the mechanical properties of frozen sand. The test results showed that the stress–strain curve can be mainly divided into three stages, with evidence of strain hardening characteristics. The strength, elastic modulus, and friction angle increased with the increase in b from 0 to 0.6, but decreased when increasing b from 0.6 to 1, whereas the cohesion varied little with the variation in b. The deformation in the direction of σ2 changed from dilative to compressive and that in the direction of σ3 remained dilative throughout. 相似文献
147.
148.
Nanocrystalline (NC) Ta thin films with various thicknesses (t = 600, 1200, and 2200 nm) were grown on Si (100) substrate by using magnetron sputtering system. A phase transformation from β-Ta to α-Ta was observed when the thickness reduced to 600 nm, which is rationalized by employing a thermodynamic model. It was interesting to find that the α-Ta phase exhibited tetrahedral pyramidal grain morphology, while the β-Ta had equiaxial grain. Hardness and strain rate sensitivity (SRS, m) were measured as a function of film thickness t. Compared with the reduction in SRS as the grain size decreased in the submicron bcc metals, the NC Ta thin films with average grain size smaller than ~72 nm showed an opposite trend, both in the α-Ta and in the β-Ta phase. Improved m was observed as the grain size reduced but the increasing trend was not continuous between different phases. This unusual variation trend of m in the NC Ta was explained by a model based on the traditional double-kink mechanism coupled with a GB-mediated dislocation process, which agrees well with the experiment results. 相似文献
149.
《International Journal of Hydrogen Energy》2021,46(69):34463-34468
To solve the problem of measuring the combustion temperature of hydrogen gas, an improved two-colour pyrometer with suspended tungsten powder was developed and calibrated by a tungsten halogen lamp. The characteristic temperature parameters of the premixed 30% H2/70% air flame, including temperature distribution, proportion, maximum value, minimum value, and average value, could be measured and calculated using the improved two-colour pyrometer method and a python code. The temperature measuring results of H2-air mixture obtained by this technique were compared with that of thermocouples and previous studies. The results verified its feasibility to measure the flame temperature structure of H2 combustion. Future work concerning the influential factors of the improved two-colour pyrometer was also mentioned. 相似文献
150.