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Injection processing parameters directly influence the final fiber length and may have a negative effect on the mechanical properties of a part. The aim of the work is to investigate and quantify the effects of the injection rate (2/10/50 [cm.sup.3/s)] on the fiber length, the distribution, and orientation during injection molding and the mechanical properties of long-glass-fiber-reinforced polypropylene (LGF/PP) by experimental and simulated methods. When the injection rate increases from 2 to 10 [cm.sup.3/s], the fiber length sharply decreases from the original 11 mm to 3.43 mm at the nozzle and 1.30 mm at the filling end, and almost 88% of the fibers are less than 3 mm when the injection rate is 50 [cm.sup.3/s]. A distinct hierarchical orientation (skin-shear-core) for the fiber distribution in the thickness is obtained via a metallographic microscope, which shows that the shear layer (here the shear stress is larger and the fiber is more inclined to oriented along the flow direction) decreases with increasing injection rate. Moreover, the numerical results of the residual fiber length and orientation at different injection rates are in accord with the trend of the measured results., INTRODUCTION Fiber-reinforced thermoplastics have become the preferred composite material for executing lightweight applications in the automotive and many other industries and have enabled a significant improvement in the mechanical properties [...]

The elastic and photocatalytic properties of multiferroic material InFeO3 under strain are calculated through density functional theory. The calculated results indicate that the intrinsic InFeO3 and the strained InFeO3 meet the mechanical stability conditions and hold a relatively larger elastic coefficient than popular multiferroic material BiFeO3. The calculated bandgap and band edge of InFeO3 under tensile strain show that InFeO3 could be a high-efficiency photocatalytic hydrogen production material. InFeO3 under tensile strain holds the ability of photocatalytic water splitting to produce hydrogen with excellent ferroelectric, mechanical properties and absorption of visible light. [ABSTRACT FROM AUTHOR]

Clustering and weak magnetic coupling of doped transition metals (TMs) have hampered the potential spintronic applications of many magnetic semiconductors. Here, the influence of the host crystal magnetic background on the magnetic coupling and clustering of TM impurities is studied theoretically, with a comparison of a series of TMs (V, Cr, Fe, Co, and Ni) in MnTe, ZnTe, and CdTe hosts. We found that the antiferromagnetic (AFM) background of MnTe degrades the clustering tendency of the studied TM impurities (except Ni). Meanwhile, the AFM background of MnTe significantly enhances the magnetic coupling of doped Fe, Co, and Ni pairs in general, either ferromagnetically (for Fe, Ni) or antiferromagnetically (for Co). The enhanced ferromagnetic coupling and weakened clustering of Fe impurities in MnTe imply that an AFM background of host semiconductors may aid the development of high TC magnetic semiconductors with intrinsic magnetism. [ABSTRACT FROM AUTHOR]

The tensile strain and oxygen vacancy effects on the electronic and magnetic properties of multiferroic material BiCoO3 have been studied by density functional theory + U calculations. It is found that the oxygen vacancy at the top of the pyramid structure along the <001> direction (denoted as O1) can be stabilized at 1+ and 2+ charge states, which significantly changes the local magnetic moment of Co ions and possibly provides net magnetic moments to the BiCoO3 system. While the tensile strain degrades the polarization of BiCoO3 about 20 μC/cm2, the formation of oxygen vacancies becomes easier as the strain increases up to 5%. It indicates that the polarization and magnetic property of BiCoO3 could be tuned by the strain and oxygen vacancies, though the polarization of BiCoO3 is slightly degraded by the oxygen vacancies. Meanwhile, the change of electronic structure and magnetic property introduced by oxygen vacancy is illustrated according to the crystal field theory. [ABSTRACT FROM AUTHOR]

The XTiO3 ( X = Mn, Fe, Co and Ni) materials with R3c structure could be grown under critical conditions based on first-principles calculations and thermodynamic stability analysis. FeTiO3 and MnTiO3 could be synthesized relatively easily under metal-rich and O-poor conditions, while NiTiO3 could be stable under Ni-rich, O-rich and Ti-poor conditions. The predicted R3c CoTiO3 under thermodynamic equilibrium conditions is suggested to be synthesized under Co-rich, O-rich and Ti-poor conditions, but the calculated phonon dispersion indicates R3c CoTiO3 becomes unstable under the dynamical conditions. The ferroelectric behavior in the XTiO3 ( X = Mn, Fe, Co and Ni) system could be dominated by the Ti ion with d0 state and the strong hybridization between Ti and O, while the magnetic property is mainly caused by the contribution of 3d transition metal. [ABSTRACT FROM AUTHOR]