Spin defects in silicon carbide (SiC) with mature wafer-scale fabrication and micro/nano-processing technologies have recently drawn considerable attention. Although room temperature single-spin manipulation of colour centres in SiC has been demonstrated, the typically detected contrast is less than 2$\%$, and the photon count rate is also low. Here, we present the coherent manipulation of single divacancy spins in 4H-SiC with a high readout contrast ($-30\%$) and a high photon count rate (150 kilo counts per second) under ambient conditions, which are competitive with the nitrogen-vacancy (NV) centres in diamond. Coupling between a single defect spin and a nearby nuclear spin is also observed. We further provide a theoretical explanation for the high readout contrast by analysing the defect levels and decay paths. Since the high readout contrast is of utmost importance in many applications of quantum technologies, this work might open a new territory for SiC-based quantum devices with many advanced properties of the host material.

Solution-based processing of two-dimensional (2D) materials provides the possibility of allowing these materials to be incorporated into large-area thin films, which can translate the interesting fundamental properties of 2D materials into available devices. Here, we report for the first time a novel chemical-welding method to achieve high-performance flexible n-type thermoelectric films using 2D semimetallic TiS nanosheets. We employ chemically exfoliated TiS nanosheets bridged with multivalent cationic metal Al to cross-link the nearby sheets during the film deposition process. We find that such a treatment can greatly enhance the stability of the film and can improve the power factor by simultaneously increasing the Seebeck coefficient and electrical conductivity. The resulting TiS nanosheet-based flexible film shows a room temperature power factor of ∼216.7 μW m K, which is among the highest chemically exfoliated 2D transition-metal dichalcogenide nanosheet-based films and comparable to the best flexible n-type thermoelectric films, to our knowledge, indicating its potential applications in wearable electronics.

To investigate the indoor air quality (IAQ) over Xi'an, the concentrations of volatile organic compounds (VOCs, including formaldehyde, benzene, toluene, o-xylene, p-xylene, n-butyl acetate, ethylbenzene, styrene, n-undecane, and total VOCs) in 471 residential rooms and 58 public rooms during 2014-2015 were determined. All the data were measured at a variety of 6-48 months after the decorations of these rooms. The results showed that formaldehyde was the most serious pollutant in almost all the monitored rooms. The concentrations of formaldehyde in residences and public places ranged from 0. ). However, the TVOC concentrations in most sites were lower than the Chinese National Standard (GB/T 18883-2002) value. In residences, the formaldehyde and TVOC concentrations in bedrooms were slightly higher than those in living rooms and other rooms. The relationships among formaldehyde and TVOC concentrations with indoor temperature, relative humidity (RH), and decorative materials (curtain, wall decoration, wood floor, and panel furniture) were also investigated. Formaldehyde levels showed strong positive correlation with indoor temperature and RH. However, the TVOC levels had a relatively weak correlation with indoor air temperature and RH. The wall decoration and panel furniture were the main sources of indoor formaldehyde, while wood floor and panel furniture were the main sources of TVOC. In addition, indoor air pollution of three selected newly decorated houses with 11 rooms was monitored monthly for one year to evaluate the relationship between indoor pollution levels and ventilation time. It was found that the concentrations of formaldehyde and TVOC decreased with ventilation time, and the duration was one year after decoration especially after summer ventilation.

This paper reports, for the first time, an analysis of the effect of High Current Pulsed Electron Beam (HCPEB) on a Mg alloy. The AZ31 alloy was HCPEB treated in order to see the potential of this fairly recent technique in modifying its wear resistance. For the 2.5J∕cm2 beam energy density used in the present work, the evaporation mode was operative and led to the formation of a “wavy” surface and the absence of eruptive microcraters. The selective evaporation of Mg over Al led to an Al-rich melted surface layer and precipitation hardening from the over saturated solid solution. Due to the increase in hardness of the top surface layer, the friction coefficient values were lowered by more than 20% after the HCPEB treatments, and the wear resistance was drastically (by a factor of 6) improved. The microhardness of the HCPEB samples was also increased significantly down to a depth of about 500μm, far exceeding the heat-affected zone (about 40μm). This is due to the effect of the propagation of the shockwave associated with this HCPEB treatment.

Divacancy defect spins in silicon carbide (SiC) are one of the promising candidates for quantum network and quantum information processing due to their attractive optical and spin properties. Although efforts have been made to investigate their properties and coherent manipulations, little is known about the properties of the optical dipole moment’s orientation of these defects, which are critically important for fluorescence enhancement and quantum communication. In this study, we determined the dipole moment’s orientation of single divacancy defects in 4H polytype SiC (4H-SiC) using tightly focused radially and azimuthally polarized laser beams through confocal microscopy. We can extract polar and azimuthal angles of the dipole moment compared with the theoretically calculated two-dimensional fluorescence intensity distributions. The polarization of photoluminescence of these different defects is measured and analyzed for comparison. These results are critical for the highly efficient nanostructure-coupled enhancement of emission and quantum communication where the dipole moment’s orientation should be known.