The Normal Force Characteristic of a Novel Magnetorheological Elastomer Based on Butadiene Rubber Matrix Compounded with the Self-Fabricated Silly Putty

In this paper, a novel magnetorheological elastomer (MRE) was prepared by dispersing carbonyl iron particles (CIPs) into a composite matrix compounded by butadiene rubber (BR) and self-fabricated Silly Putty. The rate-sensitive and magneto-induced characteristics of normal force were experimental investigated to discuss the working mechanism. The results demonstrated that the normal force increased with the compression rate and the mass fraction of boron-silicon copolymer added to the composite matrix due to the formation of the more and more B-O cross bonds which could be blocked in the C-C cross-linked network of BR. Meanwhile, the magneto-induced normal force was positively correlated with the applied magnetic field strength and the compression strain due to the decreased gap between the centers of soft magnetic particles and the increased particle intensity of magnetization. Moreover, the magneto-induced normal force continued to enhance with the increase of compression strain because the CIP chains fixed in the C-C cross-linked network could bend to a radian and CIP chains in B-O cross-linked network could rupture to form more stable and intensive short-chain structures. Besides, a simplified model was deduced to characterize the mechanism of the generation of the magneto-induced normal force. Furthermore, the normal force varied stably with the oscillatory shear strain (less than 9%) at different magnetic induction intensities and suddenly reduced when the applied oscillatory shear strain was more than 9%.

Photoelectric properties and stability of the single-layer transition metal dichalcogenides under three stress states

In this paper, the electrical and optical properties of single-layer MoS2 and single-layer WS2 in three strain states: biaxial tension, biaxial compression, biaxial tension and compression are systematically studied. All calculations are based on the first-principle of density functional theory. The results show that after biaxial tension strain, biaxial compression strain, and biaxial tension-compression strain are applied, the atomic structure, energy band structure, and optical absorption coefficient will show disparate changing trends. When the biaxial tension and compression strain intensity is less than 15%, the bond length, bond angle, and light absorption peak will have little fluctuation with the increase of strain intensity. However, compared with the other two strain states, these two crystal structures are the most volatile at this time. In addition, when 15% biaxial tensile strain is applied, the two crystals can still maintain their kinetic stability.

Evaluation of Potential Function of Core-Shell Model for PbTiO3 Ferroelectric Material and Its Application for Polarization Calculation

In this study, the core-shell model is used to calculate the electric polarization for PbTiO3 ferroelectric material, in which, the interaction potential functions among atoms are determined by the fitting method based on the results from the first principle calculation. The investigations obtained show that the remnant polarization increases under tension and decreases under compression. The remnant polarization decreases with increasing the temperature. The phase transition from the ferroelectric phase to the paraelectric phase is determined at 605K and can occur at lower temperatures of 0K, 300K, 400K, 500K if the compression strain are 8%, 6%, 5%, 2%, corresponding. The hysteresis loop shrinks as the temperature increases and degrades into a curve at the temperature of 605K.

Investigating Effect of Strain and Geometric Defects on Single Polarization Vortex in PbTiO3 Nanowires

The single polarization vortex structure in nanowire can be used to store binary data in Non-Volatile Ferroelectric Random Access Memories (NVFRAM or FRAM). However, at the nanoscale, mechanical strains or geometry defects (cracks) can affect the polarization vortex and they are one of the reasons to reduce the service life as well as the reliability of the device. In this study, the atomic simulation method using the interactive potential function based on the core-shell model is selected to investigate the effects of strain, cracks and domain wall deviations (DW) on the single polarization vortex in PbTiO3 (PTO) nanowires. The results obtained showed that the polarization vortex can appear or disappear depending on the position and size of the crack. Deviations in the DW position make the polarization vortex change the size and shape. Besides, the magnitude of the vortex investigated increases under tension strain and decreases under compression strain. Especially, in large compression strain (10%), the vortex can be disappeared.

The effect of Y on the microstructure and mechanical performance of an Mg-Al-Y casting alloy

Environmental gains of electric cars can be optimized with the use of lightweight and recyclable magnesium in the vehicle’s structural components. Ductility improvement of low-density Mg-Al alloys will extend their use in automotive body applications. The authors achieved 63% ductility improvement in Mg-6wt%Al with trace Y (1.5 ppm) due to the β-phase refinement and predicted that higher levels would not perform as well. As predicted, 0.3wt% of Y addition investigated in this study led to lower mechanical performance and β-phase refinement than those obtained with trace additions. The tensile ductility and yield strength increased by ~13% and 16%, respectively, and the compression strain to fracture by ~22%. Scanning electron and optical microscopy, X-Rays diffraction, mechanical testing and thermodynamic calculations were used to investigate the effect of 0.3wt% Y on the microstructure of Mg-6wt%Al. The matrix dissolution revealed the close association of the Al2Y and the β-Mg17Al12 phases.

Interfacial atomic Ni tetragon intercalation in a NiO2-to-Pd hetero-structure triggers superior HER activity to the Pt catalyst

Electron relocation pumps charge from Ni via tensile strain of doped Ni tetragons, compression strain of surrounding Pd atoms and the inherent electronegative difference, thus promising prominent hydrogen evolution efficiency for the Pd surface.

Collaboration between a Pt-dimer and neighboring Co–Pd atoms triggers efficient pathways for oxygen reduction reaction

Charge localization via compression strain and electronegativity difference extracts electrons from Pd and Co, thereby opening efficient oxygen reduction pathways around the Pt dimer.