Enhanced mechanical properties in β-Ti alloy aged from recrystallized ultrafine β grains

Ultrafine β grain structures with recrystallized morphologies were fabricated by severe plastic deformation and subsequent annealing in Ti-10Mo-8 V-1Fe-3.5Al alloy. The minimum mean β grain size of 480 nm was obtained for the first time as a recrystallized structure in Ti alloys. Precipitation behavior of α in subsequent aging significantly changed with decreasing the recrystallized β grain size. Both tensile strength and total ductility of the aged Ti-alloy were increased by the β grain refinement. Tensile strength of 1.6 GPa and total elongation of 9.1% were achieved in the aged specimen having the prior β grain size of 480 nm, which was attributed to its finer and more homogeneous precipitated microstructure having a mixture of nanoscale thin-plate α and globular α without side α plates along β grain boundaries

Achieving large super-elasticity through changing relative easiness of deformation modes in Ti-Nb-Mo alloy by ultra-grain refinement

Large super-elasticity approaching its theoretically expected value was achieved in Ti-13.3Nb-4.6Mo alloy having an ultrafine-grained β-phase. In-situ synchrotron radiation X-ray diffraction analysis revealed that the dominant yielding mechanism changed from dislocation slip to martensitic transformation by decreasing the β-grain size down to sub-micrometer. Different grain size dependence of the critical stress to initiate dislocation slip and martensitic transformation, which was reflected by the transition of yielding behavior, was considered to be the main reason for the large super-elasticity in the ultrafine-grained specimen. The present study clarified that ultra-grain refinement down to sub-mirometer scale made dislocation slips more difficult than martensitic transformation, leading to an excellent super-elasticity close to the theoretical limit in the β-Ti alloy

Impacts of Partial Substitution of Chemical Fertilizer with Organic Manure on the Kinetic and Thermodynamic Characteristics of Soil <i>β</i>–Glucosidase

To study the characteristics of the β–glucosidase enzymatic reaction in wheat field soil under the condition of reducing the application of chemical fertilizer, five fertilization treatments were established, including no fertilizer (CK), chemical fertilizer (F), organic fertilizer (OF), 25% organic fertilizer plus 75% chemical fertilizer (25% OF), and 50% organic fertilizer plus 50% chemical fertilizer (50% OF). The activity of β–glucosidase and its kinetic and thermodynamic characteristics were analyzed by using microplate p–nitrophenol colorimetry. The results showed that the Vmax values of soil β–glucosidase in the organic substitution of chemical fertilizer treatment were higher than those in the chemical fertilizer and no fertilizer treatments, and the Km values were lower than those in the chemical fertilizer and no fertilizer treatments at the different growth stages. The Vmax value in the 25% OF treatment was the highest at the jointing stage and that of the OF treatment was the highest at the booting stage; the Km value in the 50% OF treatment was the lowest at the different growth stages. Compared with the chemical fertilizer and no fertilizer treatments, the application of organic fertilizer effectively reduced thermodynamic parameters such as Ea, Q10, ∆H, ∆G, and ∆S at the jointing and booting stages of wheat. The thermodynamic parameters in the 25% OF treatment were the lowest at the jointing stage and those in the OF treatment were the lowest at the booting stage. A reasonable amount of organic fertilizer is more beneficial to enzymatic reactions and improves the soil quality and the ability to supply nutrients to wheat cultivation

Effect of freezing on recombinant hepatitis E vaccine

Studies have revealed that vaccines are more often exposed to sub-zero temperatures during cold chain transportation than what was previously known. Such exposure might be detrimental to the potency of temperature-sensitive vaccines. The aim of this study was to evaluate the impact of exposure to freezing on the physicochemical properties and biological activities of recombinant hepatitis E (rHE) vaccine. Changes in rHE vaccine due to freezing temperatures were analyzed with regard to sedimentation rate, antigenicity, and antibody affinity and potency. The freezing temperature of rHE was measured, then rHE vaccine was exposed to freezing temperatures below −10°C.Significant increase of sedimentation rate was noted, according to shake test and massed precipitates. In addition, the binding affinity of rHE vaccine to six specific monoclonal antibodies was significantly reduced and the in vivo potency for eliciting a protective IgG response was also partially lost, especially for anti-HEV neutralizing antibodies. Altogether, our work indicates that exposure of rHE vaccine to a temperature below −10°C results in the loss of structural integrity and biological potency of rHE vaccine