University of Science and Technology Beijing

About: University of Science and Technology Beijing is a education organization based out in Beijing, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 41558 authors who have published 44473 publications receiving 623229 citations. The organization is also known as: Beijing Steel and Iron Institute.

Orientational analysis of static recrystallization at compression twins in a magnesium alloy AZ31

Abstract: In contrast to cubic metals, the dominant recrystallization nucleation site of hexagonal magnesium is compression twins or the shear bands evolved from them. In this paper, we determine the macrotextures and microstructures of a magnesium alloy AZ31 during static recrystallization. We interpret these data according to a microtexture analysis performed with the EBSD technique of new grains formed at compression twins in the early stage of static recrystallization. The results show that the orientation characteristics in local regions during nucleation are similar to those of subgrains within compression twins or shear bands. However, the new grains mainly take the orientations of the subgrains, which have been subjected to complicated orientation rotations. This phenomenon is attributed to the large amount of their stored energy. Despite the difference between new grain orientations and those of the deformed matrix, the retained deformation texture after annealing is explained mainly by the incomplete recrystalization of magnesium.

Few-Layer Graphdiyne Nanosheets Applied for Multiplexed Real-Time DNA Detection

Abstract: Despite recent progress in 2D nanomaterials-based biosensing, it remains challenging to achieve sensitive and high selective detection. This study develops few-layer graphdiyne (GD) nanosheets (NSs) that are used as novel sensing platforms for a variety of fluorophores real-time detection of DNA with low background and high signal-to-noise ratio, which show a distinguished fluorescence quenching ability and different affinities toward single-stranded DNA and double-stranded DNA. Importantly, for the first time, a few-layer GD NSs-based multiplexed DNA sensor is developed.

Effect of microstructure and inclusions on hydrogen induced cracking susceptibility and hydrogen trapping efficiency of X120 pipeline steel

Abstract: The susceptibility to hydrogen induced cracking (HIC) was evaluated for X120 steels containing different amounts of Mn and Al in a H2S environment. The hydrogen trapping efficiency was investigated by measuring the permeability (J∞L) and the apparent diffusivity (Dapp). The results demonstrated that larger amount of the inclusions, and larger area and volume fraction of the inclusions make steels more susceptible to HIC. The steel with a microstructure consisting of granular bainite and M/A (martensite/austenite) microconstituents is more susceptible to HIC. The ability of the microstructure and the inclusions to trap hydrogen was explained in terms of the apparent diffusivity (Dapp), permeability (J∞L), and solubility of hydrogen in steels (capp). The lower the values of Dapp and J∞L and the higher the value of capp are, the more the hydrogen trapping occurs in the steel, and the more the steel is susceptible to HIC.

Tuning of Photoluminescence and Local Structures of Substituted Cations in xSr2Ca(PO4)2–(1 – x)Ca10Li(PO4)7:Eu2+ Phosphors

Abstract: Local structure modification in solid solution is an essential part of photoluminescence tuning of rare earth doped solid state phosphors. Herein we report a new solid solution phosphor of Eu2+-doped xSr2Ca(PO4)2–(1 – x)Ca10Li(PO4)7 (0 ≤ x ≤ 1), which share the same β-Ca3(PO4)2 type structure in the full composition range. Depending on the x parameter variation in xSr2Ca(PO4)2–(1 – x)Ca10Li(PO4)7:Eu2+, the vacancies generated in the M(4) site enable the nonlinear variation of cell parameters and volume, and this increases the magnitude of M(4)O6 polyhedra distortion. The local structure modulation around the Eu2+ ions causes different luminescent behaviors of the two-peak emission and induces the photoluminescence tuning. The shift of the emission peaks in the solid solution phosphors with different compositions has been discussed. It remains invariable at x ≤ 0.5, but the red-shift is observed at x > 0.5 which is attributed to combined effect of the crystal field splitting, Stokes shift, and energy trans...