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This study presents the design of a high strength titanium alloy based on the idea that the β titanium alloy with critically stable composition could precipitate ultra-fine α phase. An efficient method was used to find the composition of TC21-xV alloy in which ultra-fine α phase could be obtained. It is found that TC21-5V alloy containing ultra-fine α phase and possessing highest hardness could be obtained after solution treatment in the β single-phase region and subsequent aging. The morphology of primary and secondary α phases can be controlled by changing the solution treatment and aging temperatures. Calculation results of driving force and growth rate of secondary α phase show that the growth rate may be a decisive factor for the final size of secondary α phase after solution and aging treatments in the two-phase region. Finally, when the alloy was solution treated at 820 °C and aged at 500 °C, the highest strength of 1540 MPa was obtained. The alloy was solution treated at 820 °C and aged at 600 °C exhibited high strength of 1210 MPa with 11.4% elongation.

We propose an all-optical scheme to prolong the quantum coherence of a negatively charged nitrogen-vacancy (NV) center in diamond at cryogenic temperatures. Optical control of the NV spin suppresses energy fluctuations of the $^{3}{{{\rm A}}_{2}}$ ground states and forms an energy gap protected subspace. By optical control, the spectral linewidth of magnetic resonance is much narrower and the measurement of the frequencies of magnetic field sources has higher resolution. The optical control also improves the sensitivity of the magnetic field detection and can provide measurement of the directions of signal sources.

Poor capacity stability during long cycle and poor adhesion under high potential hinder the Lithium-manganese rich layered oxides cathode from applications, and necessary strategy for this is clearly needed. In this work, a novel aqueous binder (lithium poly (acrylic acid), Li-PAA) is introduced for stabilized cyclic performance of Li1.15Ni0.17Co0.11Mn0.57O2 materials. Contrasting with the commercial ones (polyvinylidene fluoride, PVDF), this binder is beneficial to enhance the connection between the electrode and current collector, which can improve cycle stability. In the meanwhile, optimization mechanisms are revealed via detailed measurements, which indicate the suppressed formation of spinel phase during cycling. As a result, the electrode with Li-PAA still delivers the specific capacity of 254.7 mAh g-1 with the retention of 90.77% after 200 cycles at 0.1C, higher than that of electrode with PVDF (223.6 mAh g-1,76.21%). The current subject study provides a conducive insight to develop an excellent binder based on Li-PAA for potential low-riced and environmentally friendly high energy density Li-ion batteries. [ABSTRACT FROM AUTHOR]

Nodal line semimetal (NLS) is a new quantum state hosting one-dimensional closed loops formed by the crossing of two bands. The so-called type-II NLS means that these two crossing bands have the same sign in their slopes along the radial direction of the loop, which requires that the crossing bands are either right-tilted or left-tilted at the same time. According to the theoretical prediction, Mg3Bi2 is an ideal candidate for studying the type-II NLS by tuning its spin-orbit coupling (SOC). High-quality Mg3Bi2 films are grown by molecular beam epitaxy (MBE). By in-situ angle resolved photoemission spectroscopy (ARPES), a pair of surface resonance bands around the point are clearly seen. This shows that Mg3Bi2 films grown by MBE are Mg(1)-terminated by comparing the ARPES spectra with the first principles calculations results. Moreover, the temperature dependent weak anti-localization effect in Mg3Bi2 films is observed under magneto-transport measurements, which shows clear two-dimensional (2D) e–e scattering characteristics by fitting with the Hikami–Larkin–Nagaoka model. Therefore, by combining with ARPES, magneto-transport measurements and the first principles calculations, this work proves that Mg3Bi2 is a semimetal with topological surface states. This paves the way for Mg3Bi2 to be used as an ideal material platform to study the exotic features of type-II nodal line semimetals and the topological phase transition by tuning its SOC. [ABSTRACT FROM AUTHOR]