Magnetoresistance of Ni/WSe2/Ni junctions: robustness against the thickness of WSe2.

Magnetoresistive materials are vital for the development of storage devices. Using the first-principles transport simulations with nonequilibrium Green's function calculation, we investigate the magnetoresistive properties of Ni/WSe2/Ni junctions withm-layers of WSe2(m= 1, 2, ⋯ ,6). Form≤ 2, the junctions are metallic inspite of the semiconducting nature of few-layer WSe2. However, the junctions exhibit transport gaps form> 2. Interestingly, magnetoresistance of the junctions stays around 6% when there are more than one layer of WSe2in the center, which is closely related to the robust spacial variation of interfacial properties and can be attributed to no spin flipping in tunneling regions. Our results suggest that Ni/WSe2/Ni junctions have a robust magnetoresistance which is insensitive to the thickness of WSe2.

Combined multi-band infrared camouflage and thermal management via a simple multilayer structure design.

Infrared camouflage is crucial for high-temperature objects to avoid detection, and spontaneous infrared radiation is also an important way for high-temperature objects to dissipate heat. Therefore, selective infrared emission has become significant for the coating design of surfaces such as aircraft, which require low emission in the atmospheric window band (3-5 µm and 8-14 µm) and high emission outside it (5-8 µm). This Letter employs a simple multilayer film structure to achieve selective regulation of the material emission spectrum. Combining the transfer matrix method and genetic algorithm, a multilayer film structure containing 12 layers of three high-temperature-resistant materials (SiO2, TiO2 and Ge) has been designed. It shows fairly low emissivity in two main bands of infrared detection (ε3∼5µm=0.14, ε8∼14µm=0.21) and high emissivity outside them (ε5∼8µm=0.86), and this infrared selectivity can be well maintained with the incident angle rising from 0 to 60 deg. The Poynting vector distribution in the material at different incident wavelengths is analyzed to further explore the interference mechanism to achieve spectral selective emission. The significance of this work lies in the construction of a relatively simple coating design while ensuring efficient infrared camouflage and thermal management performance.

[Effects of intervertebral disc degeneration on biomechanics behavior characteristics of L4-L5 under the vertical load].

A geometrical model of L4-L5 lumbar segment was constructed using a three-dimensional graphics software. Four conditions of the degenerated discs, i. e. light degeneration, moderate degeneration, severe degeneration and complete excision degeneration, were simulated with loading situations using finite element method under the condition of appropriate computational accuracy. By applying a vertical load of 378.93 N on L4 vertebral plate, stress nephograms on joint isthmus under four different working conditions were obtained. The results showed that the contacted area of facet joint was influenced by the degree of intervertebral disc degeneration level, which influenced the mises stress on joint isthmus. It was proved that joint isthmus was the important pressure-proof structure of the back of lumbar vertebra, and the stress values and distribution were related to structural stiffness of the back of lumbar vertebra as well as the contact area of facet joint. The conclusion could be the theoretical reference for the analysis of spinal biomechanics and artificial disc replacement as well.