Dual phases strengthening behavior of Mg-10Gd-1Er-1Zn-0.6Zr alloy

The microstructure evolution and strengthening mechanisms of Mg-10Gd-1Er-1Zn-0.6Zr(wt.%) alloy were focused in the view of the size parameters and volume fraction(fp) of dual phases(long period stacking ordered(LPSO) structures and β’ precipitates).Results show that two types of LPSO phases with different morphologies formed,and the morphology and size of both LPSO phases varied with the solution conditions.However,the volume fraction decreased monotonously with increasing solution temperature,which in turn raised the volume fraction of β’ phase during aging.The alloy exhibited an ultimate tensile strength of 352 MPa,a yield strength of 271 MPa,and an elongation of 3.5% after solution treatment at 500℃ for 12 h and aging at 200℃ for 114 h.In contrast to the LPSO phase,the β’ phase seems to play a more important role in enhancing the yield strength,and consequently,a decreased fLPSO/fβ’,ratio results in an increased yield strength.

Microstructure and corrosion behaviors of as-rolled Mg-Zn-Er alloy sheets

The corrosion behaviors and mechanism of the as-rolled Mg-x Zn-0.5Er(x=0.5, 2.0, 3.0 and 4.0, in wt.%)alloys were investigated. The potential difference between the second phase and matrix was determined by the type and size of the second phases. The dominated nano-scale W-phase on matrix in the Mg-0.5Zn-0.5Er alloy induced a sharp local pitting corrosion. However, as the volume fraction of the coarse W-phase or I-phase increased, the corrosion reaction was inclined to happen around the coarse W-phase or I-phase preferentially, leading to an obvious uniform corrosion and great acceleration of corrosion rate. The long-term immersion(14 d) results indicated that the corrosion resistance decreasing sequence was Mg-0.5Zn-0.5Er > Mg-2.0Zn-0.5Er > Mg-3.0Zn-0.5Er > Mg-4.0Zn-0.5Er.

Microstructure,mechanical properties and stretch formability of as-rolled Mg alloys with Zn and Er additions

The magnesium alloy has a unique advantage in 3C fields due to its high specific strength and excellent electromagnetic shielding characteristic.However,it is difficult to deform homogeneously because of hexagonal close-packed structure.In the present work,the microstructure,mechanical properties and stretch formability of magnesium alloy sheets with different alloying elements were investigated.It was indicated that a trace addition of Zn or/and Er made a key role in modifying texture,activating shear bands formation and precipitating nanoscale second phases,respectively,which resulted in an obvious improvement in both stretch formability and mechanical properties.The results suggested that the Mg-0.5 Zn-0.5 Er alloy sheet exhibited higher tensile strength along the rolling direction,i.e.,yield strength of 180 MPa and ultimate tensile strength of 201 MPa,accompanying with superior Erichsen value of 7.0 mm at room temperature.The good performances of the sheet were ascribed to weakening basal texture intensity,formation of shear bands and precipitation of nanoscale W-phase(Mg_(3)Zn_(3)Er_(2)).

Wake flow and vortex structures behind emergent vegetation patches elongated in the longitudinal direction

In natural rivers,patches of vegetation generally expand over their steady wake region in the streamwise direction,forming elongated patches with length(L)greater than their width(b).This paper studies how the wake flows and the vortices develop as the emergent patches expand their length in the streamwise direction.The patches are modeled with the same width but different lengths in laboratory experiments.Behind the patches,the steady wake region(L_(w))is not related to the width-related flow blockage(C_(d)ab),where C_(d) is the drag coefficient,a is the vegetation density.Instead,L_(w) is related to the length-related flow blockage(C_(d)aL).On this basis,a model is proposed for predicting L_(w),which is in good agreement with the measurements.As a patch becomes denser and/or longer(as C_(d)aL increases),the steady wake region becomes shorter(L_(w) decreases),and vortices are observed closer to the patch trailing edge,producing a turbulence of a greater magnitude beyond L_(w).When the flow blockage increases to the limit(C_(d)aL>8),the Karman vortices are observed directly behind the porous patches.These results can be used to explain the longitudinal elongation of the vegetation patches in the field.

BVAN08 enhances radiosensitivity via downregulation of DNA-PKcs towards hepatic tumor xenograft

Objective:To study the effects of the novel vanillin derivative BVAN08 on the radiosensitivity of hepatic cancer cells for the purpose of providing evidence for its potential use as a potential radiosensitive drug.Methods:Hepatic cancer Huh-7 cells labeled with luciferase were used to investigate the radiosensitivity induced by BVAN08 in vivo.Colony formation assays and flow cytometry were used to measure the apoptosis and radiosensitivity of Huh-7 cells in vitro produced by BVAN08.Histology and immunohistochemistry were used to evaluate the toxicity of BVAN08 in vivo.Results:BVAN08 induced apoptosis and cell cycle arrest of Huh-7 cells in a time-dependent manner.Moreover,BVAN08 combined with radiation increased the sensitivity of Huh-7 cells toγ-ray radiation and significantly inhibited tumor growth in vivo.The tumor inhibition rates of the BVAN08 treatment group,irradiation treatment group,and combined therapy group were 58%,38%,and 85%,respectively.The DNA-PKcs expression in tumor tissues of the BVAN08 treatment group was lower than that of the control group(P<0.01).BVAN08 inhibited the growth of Huh-7 cells in nude mice bearing tumors,without resulting in any noticeable side effects on bodyweight,livers,hearts,kidneys,or the number of peripheral white blood cells.Conclusions:As a natural food additive derivative,BVAN08 possesses the potential to be used as an effective anticancer drug to increase cell sensitivity to radiotherapy.