The impact of micro-alloying on tensile behavior at strain rates in various ranges is examined using five types of extruded Mg-0.3 at. pct Mn–0.1 at. pct X ternary alloys, where X is selected as a common element, Al, Li, Sn, Y or Zn. Microstructural observations reveal that the average grain size of these extruded alloys is between 1 and 3 μm, and these micro-alloying elements segregate at grain boundaries. In room temperature tensile and compression tests, these results show that the mechanical properties and deformation behavior are influenced by the micro-alloying element, even as a small addition of 0.1 at. pct. Mg–Mn–Y and Mg–Mn-Zn alloys show higher strength and smaller strain rate sensitivity (m-value) among the present alloys, owing to the rate-controlling mechanism as dislocation slip. On the other hand, the Mg–Mn–Li alloy exhibits the largest elongation to failure in tension and the highest strain rate sensitivity, associated with high contribution of grain boundary sliding to deformation. These differences are due to the grain boundary segregation of the micro-alloying elements. Compared to the common Mg alloys, the present ternary alloys also show a trade-off relationship between strength and ductility, which is similar to that of the well-known Mg alloys; however, these properties of the Mg–Mn system ternary alloys could be controlled via the type of micro-alloying elements with a chemical content of 0.1 at. pct.
The disposition of diadenosine 5'5"'-P1,P4-tetraphosphate (Ap4A), an endogenous dinucleotide, was investigated in rats. The degradation of Ap4A in rat plasma was very rapid and could be explained by a Michaelis-Menten equation: Km and Vmax values were 1.69 micrograms/ml and 4.32 micrograms/min/ml, respectively. Ap4A was degraded in rat plasma to ATP and AMP, but not to 2 ADP molecules, and these nucleotides were further degraded through adenosine. The degradations kinetics were examined. After intravenous bolus injection, Ap4A in plasma declined rapidly and the rate of elimination was dose-dependent: the biological half-life was about 3s at the dose of 1 mg/kg and was longer at 3 mg/kg. When Ap4A was administered by intravenous infusion (0.5 or 1.0 mg/kg/min), the plasma level rapidly reached a steady-state, which then rapidly declined after stopping the infusion. 相似文献
We show from muon spin relaxation (SR) studies on mercury HTS superconductors that a 50-fold increase in irreversibility field obtained by partial substitution of Re for Hg is due to metallisation of the Hg/Re layer. Induced superconductivity on this metallic layer doubles the overall superfluid density. This suggests a new approach to the design of high performance HTS materials: metallising one of the non-CuO2 interlayers and thereby greatly enhancing the superconducting properties. 相似文献
Abstract: We have previously reported that bilberry anthocyanins exhibit an anti‐pruritic effect in a mouse model of allergic contact dermatitis. It has been reported that anthocyanins are particularly sensitive to thermal treatment and are easily hydrolyzed to anthocyanidins when exposed to high temperatures. The objective of this study was to compare the anti‐pruritic effect of anthocyanin‐rich quality‐controlled bilberry extract and anthocyanidin‐rich degraded extract using a mouse model of allergic contact dermatitis. BALB/c mice with allergic contact dermatitis induced by 4 weeks of repeated application of 2,4,6‐trinitro‐1‐chlorobenzene (TNCB) were administered Bilberon‐25 orally for 4 weeks after sensitization with TNCB. The effect of Bilberon‐25 on pruritus was evaluated by measurement of scratching behavior. RBL‐2H3 mast cells were used to investigate the effect of Bilberon‐25 on degranulation in 48/80‐stimulated mast cells. Compared with nonheated Bilberon‐25, the proportion of anthocyanins in heated Bilberon‐25 decreased, and the proportion of anthocyanidins was increased in heated‐time dependent manner. Treatment with non‐heated Bilberon‐25 significantly attenuated the TNCB‐induced increase in scratching behavior, whereas treatment with 2 h‐heated Bilberon‐25 did not. Moreover, 300 μg/mL nonheated Bilberon‐25 showed significant inhibition of degranulation in RBL‐2H3 mast cells, whereas 2 h‐heated Bilberon‐25 had no effect at any concentration studied. It is assumed that the inhibitory effect of bilberry anthocyanins on pruritus might be mediated, at least in part, by its inhibitory effect on mast cell degranulation. In conclusion, the anthocyanin‐rich but not anthocyanidin‐rich bilberry extract may be a useful dietary supplement for skin diseases involving pruritic symptoms, such as chronic allergic contact dermatitis, atopic dermatitis, and rhinitis. 相似文献
The crystal structure of Sr2Y0.8Ca0.2Co2O6is orthorhombic below 270 K (Immm, a = 3.84029(7) Å, b = 3.80691(6) Å and c = 19.4980(3) Å at 20 K), transformed from tetragonal (I4/mmm, a = 3.82765(6) Å and c = 19.5795(3) Å) at 295 K. The crystal structure distortion is accompanied by an anomalous temperature dependence of the degree of buckling of the CoO2plane and is correlated with the development of anisotropic antiferromagnetic ordering of magnetic moments (2.93(2) Bper Co at 20 K). A magnetically glassy state below about 35 K and variable range hopping conduction below about 64 K forwere found by magnetic susceptibility and electrical resistivity measurements.相似文献
The NaCl/water solutions of commercial poly(vinyl alcohol) (a-PVA) with the degrees of polymerization and saponification of 1730 and 99.39%, respectively were gel-spun into methanol (–30°C) and then the removed NaCl dry-filaments were drawn at 200°C. The draw ratio showed the maximum at NaCl concentration CN = 3 wt% (polymer concentration CP = 150 kg/m3). The Young's modulus and strength at break were 95 and 6 GPa ( = 19). In the case of DMSO system (CP = 170 kg/m3), the Young's modulus was 52 GPa ( = 25) and the strength at break was 3.3 GPa. Under a polarized microscope, the fine lateral structure was observed for the DMSO system, but not for the NaCl system, that is, the smooth structure was recognized. The smooth structure, like a Netlon packing net for oranges, might be considered to result in heightening of mechanical properties. 相似文献