The thermal shock behavior of ZrB2-SiC ceramics was studied with water, air and methyl silicone oil as quenching media, respectively. The temperature of all coolants was room temperature （25℃） and the residual stre...
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The thermal shock behavior of ZrB2-SiC ceramics was studied with water, air and methyl silicone oil as quenching media, respectively. The temperature of all coolants was room temperature （25℃） and the residual strength of the ceramics after quenching was tested. The strength of the ceramics after water quenching had an obvious drop when the temperature difference, AT, was about 275℃, while the residual strength of the specimens quenched by air and silicone oil only varied a little and even increased slightly when the temperature difference was higher than 800℃. The different thermal conductive coefficient of the coolants and surface heat transfer coefficient resulted in the differences in the thermal shock behavior. The formation of oxidation layer was beneficial for improving the residual strength of the ceramics after quenching.
It has been widely accepted that planar boron structures, composed of triangular and hexagonal motifs are the most stable two-dimensional (2D) phases and likely precursors for boron nanostructures. Here we predict, ba...
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It has been widely accepted that planar boron structures, composed of triangular and hexagonal motifs are the most stable two-dimensional (2D) phases and likely precursors for boron nanostructures. Here we predict, based on an ab initio evolutionary structure search, a novel 2D boron structure with nonzero thickness, which is considerably, by 50 meV/atom, lower in energy than the recently proposed α-sheet structure and its analogues. In particular, this phase is identified for the first time to have a distorted Dirac cone, after graphene and silicene the third elemental material with massless Dirac fermions. The buckling and coupling between the two sublattices not only enhance the energetic stability, but also are the key factors for the emergence of the distorted Dirac cone.
A combined ME composite structure is made of several cylindrical layered composites in series or parallel *** to the cylindrical structure,the combined structure does not need more *** characteristics of multi-resonan...
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A combined ME composite structure is made of several cylindrical layered composites in series or parallel *** to the cylindrical structure,the combined structure does not need more *** characteristics of multi-resonance frequencies have been *** resonance frequency of the structure can be adjusted by changing the cylinder diameter of the corresponding cylindrical layered *** number of resonance frequencies increases as the number of cylindrical layered composites *** multi-resonance frequencies behavior makes these cylindrical layered composite structures suitable for applications in multifuctional devices with multi-frequencies operation.
Based on the first-principles band structure calculations, we investigate the effects of hydrostatic pressure on the conventional insulator (CI) Sb2Se3 and predict that it undergoes a topological quantum phase transit...
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Based on the first-principles band structure calculations, we investigate the effects of hydrostatic pressure on the conventional insulator (CI) Sb2Se3 and predict that it undergoes a topological quantum phase transition from a CI to a nontrivial topological insulator at a critical pressure value. The pressure-induced topological quantum phase transition is confirmed by calculating the evolution of the bulk energy gap as a function of pressure, the inversion of energy band structure, and the Z2 topological invariant, as well as the existence of the Dirac-like topological surface states. Our predictions can be tested by both spectroscopy and transport experiments.
We describe the use of individual zinc oxide (ZnO) micro/nanowires in an electrochemical biosensor for uric acid. The wires were synthesized by chemical vapor deposition and possess uniform morphology and high crystal...
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A new lead-free BNT-based piezoelectric ceramics of (1 - x)Bi 0.5Na0.5TiO3-xBi(Al0.5Ga 0.5)O3 (x = 0, 0.02, 0.03, 0.04, and 0.05) were synthesized using a conventional ceramic fabrication method. Their structures and ...
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In this paper, ramie fiber and lotus petiole fiber were compared in structure and composition. The structure and composition of the two fibers were probed with SEM, TG and FT-IR.
In this paper, ramie fiber and lotus petiole fiber were compared in structure and composition. The structure and composition of the two fibers were probed with SEM, TG and FT-IR.
Low-temperature sintering and properties of low temperature co-fired ceramics materials based on a typical Ca-Al-B-Si-O glass and various ceramic fillers such as (Zr0.8Sn0.2)TiO4, (Ca 0.5Mg0.5)TiO3, BaSm2Ti 4O12 and C...
Application-oriented nanomaterial design and fabrication are highly necessary and are turning into a new trend nowadays. In this paper, large-scale patterned ZnO nanorod arrays (NRAs) with tunable arrangement, period ...
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