Relationships between femoral strength evaluated by nonlinear finite element analysis and BMD,material distribution and geometric morphology

Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of better measures of femoral strength using the clinically

Lotus Leaf‑Derived Gradient Hierarchical Porous C/MoS2 Morphology Genetic Composites with Wideband and Tunable Electromagnetic Absorption Performance

Inspired by the nature,lotus leaf-derived gradient hierarchical porous C/MoS2 morphology genetic composites(GHPCM)were successfully fabricated through an in situ strategy.The biological microstructure of lotus leaf was well preserved after treatment.Different pores with gradient pore sizes ranging from 300 to 5μm were hierarchically distributed in the composites.In addition,the surface states of lotus leaf resulted in the Janus-like morphologies of MoS2.The GHPCM exhibit excellent electromagnetic wave absorption performance,with the minimum reflection loss of−50.1 dB at a thickness of 2.4 mm and the maximum effective bandwidth of 6.0 GHz at a thickness of 2.2 mm.The outstanding performance could be attributed to the synergy of conductive loss,polarization loss,and impedance matching.In particularly,we provided a brand-new dielectric sum-quotient model to analyze the electromagnetic performance of the non-magnetic material system.It suggests that the specific sum and quotient of permittivity are the key to keep reflection loss below−10 dB within a certain frequency range.Furthermore,based on the concept of material genetic engineering,the dielectric constant could be taken into account to seek for suitable materials with designable electromagnetic absorption performance.

Preparation and Characterization of Multi Shape ZnO/PVDF Composite Materials

Two different morphologies of ZnO（lotus-shaped, rod-shaped） and ZnO/PVDF composite materials were prepared. The morphologies of ZnO and composite materials were characterized by scanning electron microscopy（SEM） and transmission electron microscopy（TEM）. Fourier transform infrared spectroscopy（FT-IR）, thermal gravimetry（TG）, and X-ray diffraction（XRD） were also used to characterize the chemical structures and phase composites of ZnO and ZnO/PVDF composite materials. Breakdown voltage, dielectric constant and dielectric loss of ZnO/PVDF composite materials were also tested. Microstructure analysis showed that ZnO nanoparticles dispersed uniformly in the matrix. And the dielectric constant expresses a significantly improvement while the dielectric loss and breakdown voltage expresses no significant change. Moreover, dielectric constant keeps an improvement tendency with increasing content of ZnO.

Microstructure Morphologies of Asphalt Binders using Atomic Force Microscopy

We investigated microstructure morphologies of three asphalts（SK, Karamay, and Esso） used in China using atomic force microscopy（AFM）. The topography and phase contrast images were obtained. Topographic profile and three dimensional images were described. Roughnesses of microstructure were calculated. And the chemical compositions of asphalt were tested to explain the microstructural mechanism of the asphalt. The results show that the topography and phase image in atomic force microscopy are appropriate to evaluate the microstructure of the asphalt binder. There are significant differences in microstructural morphologies including bee-like structure, topographic profile, 3D image, and roughness for three asphalts in this study. There are three different phases in microstructure of asphalt binder. The oil source and chemical composition of asphalt, especially asphaltenes content have a great influence on the microstructure.

Runout of submarine landslide simulated with material point method

Most of the present knowledge on submarine landslides relies upon back-analysis of post-failure deposits identified using geophysical techniques.In this paper,the runout of slides on rigid bases is explored using the material point method（MPM）with focus on the geotechnical aspects of the morphologies.In MPM,the sliding material and bases are discretised into a number of Lagrangian particles,and a background Eulerian mesh is employed to update the state of the particles.The morphologies of the slide can be reproduced by tracking the Lagrangian particles in the dynamic processes.A real case history of a submarine slide is back-analyzed with the MPM and also a depth-averaged method.Runout of the slides from steep slopes to moderate bases are reproduced.Then different combinations of soil and basal parameters are assumed to trigger runout mechanisms of elongation,block sliding and spreading.The runout distances predicted by the MPM match well with those from large deformation finite element analysis for the elongation and block sliding patterns.Horst and grabens are shaped in a spreading pattern.However,the current MPM simulations for materials with high sensitivities are relatively mesh sensitive.

Composites of sodium manganese oxides with enhanced electrochemical performance for sodium-ion batteries: Tailoring properties via controlling microstructure

Composites of Na_(0.44)Mn O_2, Na_(0.7)Mn O_(2.05), and Na_(0.91) Mn O_2 were synthesized by facile solid-state reaction, ball milling, and annealing methods. Two different composites of identical overall composition but drastically different morphologies and microstructures were synthesized. A composite of a hierarchical porous microstructure with primary and secondary particles(i.e., a "meatball-like" microstructure) achieved an excellent stable capacity of 126 m A h g^(-1) after 100 cycles. The rate capability of the composite could be dramatically enhanced by another round of high-energy ball milling and reannealing; subsequently, a composite that was made up of irregular rods was obtained, for which the capacity was improved by more than 230% to achieve ~53 m A h g^(-1) at a particularly high discharge rate of 50 C. This study demonstrated the feasibility of tailoring the electrochemical performance of electrode materials by simply changing their microstructures via facile ball milling and heat treatments, which can be particularly useful for optimizing composite electrodes for sodium-ion batteries.

Magnetic and electrochemical behavior of rhombohedral α-Fe_2O_3 nanoparticles with (104) dominant facets

Uniform rhombohedral α-Fe2O3 nanoparticles, -60nm in size, were synthesized via a triphenyl- phosphine-assisted hydrothermal method. Scanning electron micrograph （SEM） and transmission electron micrograph （TEM） analyses showed that the as-synthesized rhombohedral nanoparticles were enclosed by six （1 04） planes. The concentration of triphenylphosphine played an important role in morphological evolution of the α-Fe2O3 nanoparticles. The as-prepared rhombohedral nanoparticles possessed remanent magnetization Mr of 2.6 × 10^-3 emu/g and coercivity Hc of 2.05 Oe, both lower than those of other α-Fe2O3 particles with similar size, indicating their potential applications as superparamagnetic precursor materials. Furthermore, these rbombohedral α-Fe2O3 nanoparticles exhibited good sensor capability toward H2O2 with a linear response in the concentration range of 2-20 mM.