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The effect of solid solution cooling rate on mechanical properties and the morphology of strip α phase of TB17 titanium alloy was studied by Gleeble thermal simulation compression testing machine, microhardness tester, scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that after solid solution of TB17 titanium alloy with basket-weave microstructure in α+β phase region, when the solid solution cooling rate is 200℃/min, the microhardness of the titanium alloy is 250HV. With the decrease of solid solution cooling rate, the microhardness increases gradually. When the solid solution cooling rate is reduced to 1℃/min (furnace cooling), the microhardness increases to 320HV. And TB17 titanium alloy occurs β→α phase transformation during cooling process, and secondary α phase precipitates on β matrix, and the strip-shaped α phase transforms into "fork-like" structure. As the solid solution cooling rate decreases, the "fork-like" structure gradually becomes thicker and larger. When the rate is 40℃/min, the width of the "fork-like" structure is about 14 nm. When the rate is 10℃/min, the width is about 100 nm. When the rate is 1℃/min (furnace cooling), the width is about 300 nm. When the solid solution cooling rate is greater than 10℃/min, the side and end faces of the strip-shaped α phase are wrapped with the rhombohedral martensite α″ phase, and the existence of the martensite phase promotes the transformation of α phase and the formation of the "fork-like" structure. When the solid solution cooling rate is gradually reduced to about 1℃/min which is equivalent to the furnace cooling rate, the "fork-like" structure becomes thicker, the orthorhombic martensite phase on the end and side faces of the strip-shaped α phase disappears, and α″→α phase transformation occurs.

Bereavement of one or both parents is known to cause many kinds of internalizing and externalizing problems in adolescents. However, less is known about factors that are protective of the mental health of orphaned adolescents and differences by their gender and orphanhood type. To fill these gaps, the current study used a sample from southwestern China to test the association between types of orphans, life satisfaction, adolescents' psychological distress and problem behaviours. The results showed that orphan girls were prone to have lower levels of problem behaviours but higher levels of psychological distress than orphan boys. Female paternal orphans tended to have the highest psychological distress, while male paternal orphans tended to have the lowest psychological distress. In addition, school satisfaction had a stronger association with problem behaviour, and self‐satisfaction had a stronger association with psychological distress. Interventions and preventive measures aimed at reducing the psychological distress of orphans could benefit from the findings regarding the correlates of psychological distress and the most vulnerable group among orphans. [ABSTRACT FROM AUTHOR]

Because of the variety and complexity of solid-state phase transformation characteristics of titanium alloys, the relationship between their microstructure and performance has always been one of the hot topics in the field of titanium alloy materials science. By adjusting the composition, processing technology and heat treatment process parameters of titanium alloys, the microstructure type and parameters of titanium alloy parts can be adjusted to a certain extent to achieve the best matches in strength, plasticity, toughness, fatigue and fatigue crack propagation rate, etc. In this paper, based on the comparison of four typical microstructure characteristics including equiaxed microstructure, bimodal microstructure, lamellar microstructure, basket weave microstructure and their thermo-mechanical controlling technologies, taking the TC21 titanium alloy, TC4-DT titanium alloy, TC32 titanium alloy and TB17 titanium alloy for aviation use as examples to review the properties of strength, plasticity, fracture toughness, fatigue life and fatigue crack propagation rate, which can provide a reference basis for reasonably choosing microstructure parameters, optimizing properties, stabilizing mass production quality of titanium alloy products.

Bile reflux (BR) was considered to be an independent risk factor for the development of precancerous gastric lesions and GC. Dendrobium officinale polysaccharides (DOP) show a novel potential in preventing the progress of gastric cancer. However, the specific mechanism of DOP that causes such activities remains a mystery. This study aimed to investigate the effects of DOP on chenodeoxycholic acid (CDCA)-induced gastric intestinal metaplasia and explore the underlying mechanisms. Different concentrations of DOP had no significant damage to normal GSE-1 cells and gastric intestinal metaplasia model cells by CCK-8 assay. After DOP treatment, the mRNA and protein expression of CDX2 (p < 0.01) and HNF4α (p < 0.01) were decreased, and HO-1 (p < 0.05) and TFF2 (p < 0.01) were increased. The NRF2 protein expression was slightly upregulated (p < 0.05), and H-DOP further promoted NRF2 protein expression in the nucleus (p < 0.05). Hence, our findings reveal that DOP could be used as a potential anti-inflammation supplement by activating NRF2/HO-1 and modulating the HNF4α/CDX2 signaling pathway to inhibit the progress of CDCA-induced gastric intestinal metaplasia. [ABSTRACT FROM AUTHOR]

The dynamic shearing experiment was been done by using split Hopkinson pressure bar(SHPB) technique in TC32 alloy with lamellar, bimodal and basket microstructures. The damage Characteristics of TC32 alloy was investigated by using optical microscope(OP) and scanning electron microscopy(SEM). The results show that the critical fracture velocity is 2400 s-1, 2700 s-1, and 2600 s-1 for lamellar, bimodal, and basket microstructures respectively. The bimodal microstructure exhibit the best Dynamic mechanical behavior compared with the other two microstructures. Adiabatic shear bands(ASBs) and microvoids initiation, growth, and coalescence to damage in adiabatic shear bands(ASBs) were observed in all of three microstructures. Also, microvoids initiation and growth are prior to the interface between ASBs and matrix. Investigation indicated that plastic flow characteristic is not obvious at the interface between ASBs and matrix, which observed long crack in lamellar microstructure. In bimodal microstructure, fibrous a adiabatic shear bands(ASBs) and surrounding region are shown. Because of strong shear deformation, the plastic flow characteristic appears clearly, and primary α phase was elongated. Microvoids initiation is also prior to the α/β phase boundaries. The damage characteristics of basket microstructure are similar to bimodal microstructure. But unlike lamellar and basket microstructures, the microvoids are initiatied when the acicular primary α phase arranged in order is perpendicular to the adiabatic shear bands(ASBs) in lamellar microstructure. ASBs is mostly consisted of equiaxed grains, and the deformation mechanism still wasn't defined.