Effect of PAN-based and pitch-based carbon fibres on microstructure and properties of continuous Cf/ZrB2-SiC UHTCMCs

In this paper the microstructure and mechanical properties of two different C_f/ZrB₂-SiC composites reinforced with continuous PyC coated PAN-derived fibres or uncoated pitch-derived fibres were compared.Pitch-derived carbon fibres showed a lower degree of reaction with the matrix phase during sintering compared to PyC/PAN-derived fibres. The reason lies in the different microstructure of the carbon. The presence of a coating for PAN-derived fibres was found to be essential to limit the reaction at the fibre/matrix interface during SPS. However, coated bundles were more difficult to infiltrate, resulting in a less homogeneous microstructure.As far as the mechanical properties are concerned, specimens reinforced with coated PAN-derived fibres provided higher strengths and damage tolerance than uncoated pitch-derived fibres, due to the higher degree of fibre pull-out. On the other hand, the weaker fibre/matrix interface resulted in lower interlaminar shear, off-axis strength and ablation resistance.     

Dual-phase rare-earth-zirconate high-entropy ceramics with glass-like thermal conductivity

A series of rare earth zirconates (RE₂Zr₂O₇) high-entropy ceramics with single- and dual-phase structure were prepared. Compared with La₂Zr₂O₇ and Yb₂Zr₂O₇, the smaller “rattling” ions (Yb³⁺, Er³⁺, Y³⁺) have been incorporated into pyrochlore lattice in (La_0.2Nd_0.2Y_0.2Er_0.2Yb_0.2)₂Zr₂O₇ (LNYEY) while larger ions (La³⁺, Nd³⁺, Sm³⁺, Eu³⁺) incorporated into fluorite lattice in (La_0.2Nd_0.2Sm_0.2Gd_0.2Yb_0.2)₂Zr₂O₇ (LNSGY). Due to high-entropy lattice distortion and resonant scattering derived from smaller ions Yb³⁺, Er³⁺, and Y³⁺, LNYEY shows a lower glass-like thermal conductivity (1.62-1.59 W m^-1 K^-1, 100-600℃) than LNSGY (1.74-1.75 W m^-1 K^-1, 100-600℃). Moreover, LNYEY and LNSGY exhibit enhanced Vickers’ hardness (LNYEY, H_v = 11.47 ± 0.41 GPa; LNSGY, H_v = 10.96 ± 0.26 GPa) and thermal expansion coefficients (LNYEY, 10.45 × 10^-6 K^-1, 1000℃; LNSGY, 11.02 × 10^-6 K^-1, 1000℃). These results indicate that dual-phase rare-earth-zirconate high-entropy ceramics could be desirable for thermal barrier coatings.     

水泥半终粉磨系统生产矿渣粉的实践

为了提高公司综合经济效益，充分发挥目前现有的水泥半终粉磨系统生产能力大、电耗低的特点，利用水泥销售淡季间隔生产经济效益较好的矿渣粉。经过调整和部分改造，半终粉磨系统运行情况良好，效果显著。     

Performance Evaluation of Inversion Mode and Junctionless Dual-Material Double-Surrounding Gate Si Nanotube MOSFET for 5-nm Gate Length

Semiconductors - In this work, drain current ID for 5-nm gate length with dual-material (DM) double-surrounding gate (DSG) inversion mode (IM) and junctionless (JL) silicon nanotube (SiNT) MOSFET...     

Audiogram matching in hearing aid using approximate arithmetic

Multidimensional Systems and Signal Processing - Filter banks are the major signal processing blocks that dissipate large amount of power in a portable digital hearing aid device. The power...     

CHESDA: continuous hybrid and energy-efficient secure data aggregation for WSN

The Journal of Supercomputing - Data aggregation is an effective mechanism to prolong lifetime in the wireless sensor networks by preventing extra data transmission. However, it may have some...     

Circular Disk with Radial Internal Crack Under the Action of Model Contact Loads

Materials Science - We solve the plane problem of the theory of elasticity for a circular disk weakened by an arbitrarily located internal radial crack subjected to the action of a model contact...     

Detailed Balance Broken by Catch Bond Kinetics Enables Mechanical-Adaptation in Active Materials

Unlike nearly all engineered materials which contain bonds that weaken under load, biological materials contain “catch” bonds which are reinforced under load. Consequently, materials, such as the cell cytoskeleton, can adapt their mechanical properties in response to their state of internal, non-equilibrium (active) stress. However, how large-scale material properties vary with the distance from equilibrium is unknown, as are the relative roles of active stress and binding kinetics in establishing this distance. Through course-grained molecular dynamics simulations, the effect of breaking of detailed balance by catch bonds on the accumulation and dissipation of energy within a model of the actomyosin cytoskeleton is explored. It is found that the extent to which detailed balance is broken uniquely determines a large-scale fluid-solid transition with characteristic time-reversal symmetries. The transition depends critically on the strength of the catch bond, suggesting that active stress is necessary but insufficient to mount an adaptive mechanical response.     

Verification of Compliance for Multilevel Models in Individual Trace Semantics

Programming and Computer Software - This paper presents new verification techniques that target to prove multimodel compliance in terms of individual trace semantics. As compared to traditional...