Enhanced cavity coupling to silicon vacancies in 4H silicon carbide using laser irradiation and thermal annealing

The negatively charged silicon monovacancy VSi− in 4H silicon carbide (SiC) is a spin-active point defect that has the potential to act as a qubit in solid-state quantum information applications. Photonic crystal cavities (PCCs) can augment the optical emission of the VSi−, yet fine-tuning the defect–cavity interaction remains challenging. We report on two postfabrication processes that result in enhancement of the V1′ optical emission from our PCCs, an indication of improved coupling between the cavity and ensemble of silicon vacancies. Below-bandgap irradiation at 785-nm and 532-nm wavelengths carried out at times ranging from a few minutes to several hours results in stable enhancement of emission, believed to result from changing the relative ratio of VSi0 (“dark state”) to VSi− (“bright state”). The much faster change effected by 532-nm irradiation may result from cooperative charge-state conversion due to proximal defects. Thermal annealing at 100 °C, carried out over 20 min, also results in emission enhancements and may be explained by the relatively low-activation energy diffusion of carbon interstitials Ci, subsequently recombining with other defects to create additional VSi−s. These PCC-enabled experiments reveal insights into defect modifications and interactions within a controlled, designated volume and indicate pathways to improved defect–cavity interactions.

Indirect Drying and Coking Characteristics of Coking Coal with Soda Residue Additive

To improve indirect drying efficiency, the effect of soda residue on the drying characteristics of coking coal were studied using a self-made indirect drying system. A tube furnace was used in the dry distillation of coal samples with soda residue, and the coke properties were analyzed. The results indicated that the soda residue has a significant influence on the increase in the heating rate of coal samples in the temperature distribution range of 90 to 110 °C. With the addition of 2%, 5%, and 10% soda residue, the drying rates increased by 11.5%, 25.3%, and 37.3%, respectively at 110 °C. The results of dry distillation show that addition of 2%, 5% and 10% soda residue decreases the carbon loss quantity by 4.67, 4.99, and 8.82 g, respectively. The mechanical strength of coke samples satisfies the industrial conditions when the soda residue ratio ranges from 2% to 5%. Soda residue can improve the active point of coke dissolution reaction and inhibit coke internal solution. Economically, coking coal samples mixed with soda residue have an obvious energy saving advantage in the drying process. Energy saving analysis found that it can reduce cost input by 20% than that of the normal drying method.

Friedel-Crafts alkylation modification and hydrophilic soft finishing of meta aramid

Based on the Friedel-Crafts alkylation reaction, epichlorohydrin is applied to decorate the meta aramid to enhance the comfort of the fabrics. It is obviously more perfect that the samples are treated with the hydrophilic soft finishing agent. In this paper, the effects of modification and finishing time on the structure and properties of meta aramid are studied. The results indicate that the surface roughness, polarity, active point, and wetting property of the modified fabrics are increased, and the loading rate and fastness of the finishing agent on the meta aramid are enhanced. After finishing, the wetting time and the time of water transfer from the surface to the bottom become shorter in the fabrics, and the water absorption rate becomes faster, the core absorption height rises by 60%, the bending stiffness lowers by 39%, the moisture permeability increases by 5.9%, the permeability decreases by 3.6%, and the friction electric voltage reduces by 78%, The longitudinal and weft secondary combustion time increase by 0.3 s and 0.2 s, the smoldering time increase by 0.3 s, and the improving rate of damage length are 5.4% and 7.6%, respectively.

Structural and Photoluminescence Analysis on the Implantation of Carbon and Proton for the Creation of Damage-Assisted Emission in Silicon

We study the induced defects in the depth profiling of the silicon structure after being implanted with carbon and followed by high energy proton irradiation. It has been reported before that the formation of the optically active point-defect, specifically the G-centre is due to the implantation and irradiation of carbon and proton, respectively. It is crucial to quantify the diffusional broadening of the implanted ion profile especially for proton irradiation process so that the radiation damage evolution can be maximized at the point-defect formation region. Profiling analysis was carried out using computational Stopping and Range of Ions in Matter (SRIM) and Surrey University Sputter Profile Resolution from Energy Deposition (SUSPRE) simulation. The energies of carbon ions adopted for this investigation are 10, 20, 30, and 50 keV, while proton irradiation energy was kept at 2 MeV. Photoluminescence measurements on silicon implanted with carbon at different energies were carried out to study the interrelation between the numbers of vacancies produced during the damage event and the peak emission intensities.

Recent Advances in Single Crystal Diamond Device Fabrication for Photonics, Sensing and Nanomechanics

In the last two decades, the use of diamond as a material for applications in nanophotonics, optomechanics, quantum information, and sensors tremendously increased due to its outstanding mechanical properties, wide optical transparency, and biocompatibility. This has been possible owing to advances in methods for growth of high-quality single crystal diamond (SCD), nanofabrication methods and controlled incorporation of optically active point defects (e.g., nitrogen vacancy centers) in SCD. This paper reviews the recent advances in SCD nano-structuring methods for realization of micro- and nano-structures. Novel fabrication methods are discussed and the different nano-structures realized for a wide range of applications are summarized. Moreover, the methods for color center incorporation in SCD and surface treatment methods to enhance their properties are described. Challenges in the upscaling of SCD nano-structure fabrication, their commercial applications and future prospects are discussed.

When Loyalty Goes Mobile: Effects of Mobile Loyalty Apps on Purchase, Redemption, and Competition

This research investigates how a shift from traditional loyalty cards to mobile-driven loyalty apps affects consumers’ reward redemption patterns, purchase behaviors, and store-level competition. The findings indicate that loyalty app adoption is associated with increased expenditure and purchase frequency as well as more active point redemption. In a multivendor loyalty program (MVLP) context, the use of loyalty apps is associated with spillover effects in which case customers visit more stores that they had not previously considered and exhibit diminished allegiance to their focal shop after they adopt a loyalty app. Finally, the adoption of loyalty apps is related to deal-prone behaviors because informed consumers tend to selectively purchase highly discounted products. Our findings provide several valuable implications for managers and platform owners who are considering launching mobile loyalty programs (LPs) and participating in an MVLP market. Although the merits of loyalty app adoption are apparent, we caution against potential downsides at individual store levels. Many customers are likely to succumb to deals, selectively purchasing highly discounted products with low margins through loyalty apps. The thrust of LPs should be directed toward fostering a strong connection with a brand, going beyond the promise of deals and promotions.