Complete phase diagram and topological properties of interacting bosons in one-dimensional superlattices

The interacting bosons in one-dimensional inversion-symmetric superlattices are investigated from the topological aspect. The complete phase diagram is obtained by an atomic-limit analysis and quantum Monte Carlo simulations and comprises three kinds of phases: superfluid, persisted charge-density-wave and Mott insulators, and emergent insulators in the presence of nearest-neighbor hoppings. We find that all emergent insulators are topological, which are characterized by the Berry phase $\pi$ and a pair of degenerate in-gap boundary states. The mechanism of the topological bosonic insulators is qualitatively discussed and the ones with higher fillings can be understood as a $\frac{1}{3}$-filling topological phase on a background of trivial charge-density-wave or Mott insulators.Comment: 6 pages, 8 figures. Accelpted for publication in Phys. Rev.

Non-adopters of Social Media: Comparing their Lifestyles, Perceived Innovation Attributes, and Sociodemographic Attributes with All-adopters, Partial-adopters, and Minimum-adopters

This study adopted Rogers’ diffusion of innovation model to investigate the adoption of three social media with high penetration in Taiwan—Facebook, Line, and email. Special attention was paid to identifying the factors that differentiated the non-adopters (who did not adopt any of the three social media) from the all-adopters (who adopted all three social media), the partial-adopters (who adopted two social media), and the minimum-adopters (who adopted only one social medium). Two methods were adopted; one was to conduct 20 intensive interviews and the other was to administer a nationwide telephone survey with 1042 valid questionnaires. Two conclusions were obtained: (1) The characteristics of the non-adopters were congruent with those of the laggards in Rogers’ model, demonstrating that the non-adopters were less educated, less affluent, older, and used mass media less frequently than the other types of adopters; (2) the lifestyles of the non-adopters differed greatly from those of all-adopters, partial-adopters, and minimum-adopters

LOWER DEVONIAN (PRAGIAN) BRACHIOPODS FROM THE DASHATIAN SECTION, GUANGXI, SOUTH CHINA

Lower Devonian brachiopods in South China are very rare since most areas lack deposits owing to an uplift movement of the Guangxi (Caledonian) Orogeny. In this paper, we describe a brachiopod fauna consisting of 13 species in 12 genera from the Nagaoling Formation at the Dashatian section in the suburb area of the Nanning City, Guangxi, South China. This fauna is dominated by small rhynchonellide and spiriferide species, along with chonetidines, strophomenides, atrypides, athyridides and others. The early Pragian age for the brachiopod-bearing horizons in the Nagaoling Formation is constrained by the associated early Pragian conodonts Eognathodus sulcatus Zone. About 33% genera of the brachiopod fauna are endemic to South China, therefore they do not provide any clear evidence for its paleobiogeographical link to the faunas of Europe, Australia, or North America. This fauna is paleoecologically interpreted as being deposited in a shallow, oxygen-rich, low to moderate energy, subtidal palaeoenvironment in the early Pragian and it corresponds to the benthic assemblage BA2 to upper BA

A Niche Analysis of Three Interpersonal Communication Technologies: Examining the Competition among Facebook, Line, and Email

Adopting Dimmick’s niche theory as its theoretical framework, this study examined the gratifications obtained and gratification opportunities from Facebook, Line, and email to understand the competitive relationships among the three interpersonal media in Taiwan. This study first conducted twenty intensive interviews to construct questionnaire items to measure users’ gratifications obtained and gratification opportunities from the three media. Then, a telephone survey was conducted to collect data and 1042 valid calls were obtained. The data analysis shows that (1) among the three interpersonal media, Line had the widest niche breadth and the highest scores of competitive superiority and competed strongly with Facebook; and (2) the competitive superiority scores of a medium were a powerful predictor of the use history of that medium

Multistaged discharge constructing heterostructure with enhanced solid-solution behavior for long-life lithium-oxygen batteries.

Inferior charge transport in insulating and bulk discharge products is one of the main factors resulting in poor cycling stability of lithium-oxygen batteries with high overpotential and large capacity decay. Here we report a two-step oxygen reduction approach by pre-depositing a potassium carbonate layer on the cathode surface in a potassium-oxygen battery to direct the growth of defective film-like discharge products in the successive cycling of lithium-oxygen batteries. The formation of defective film with improved charge transport and large contact area with a catalyst plays a critical role in the facile decomposition of discharge products and the sustained stability of the battery. Multistaged discharge constructing lithium peroxide-based heterostructure with band discontinuities and a relatively low lithium diffusion barrier may be responsible for the growth of defective film-like discharge products. This strategy offers a promising route for future development of cathode catalysts that can be used to extend the cycling life of lithium-oxygen batteries

Operation Efficiency Optimization for Permanent Magnet Synchronous Motor Based on Improved Particle Swarm Optimization

In this paper, an improved online particle swarm optimization (PSO) is proposed to optimize the traditional search controller for improving the operating efficiency of the permanent magnet synchronous motor (PMSM). This algorithm combines the advantages of the attraction and repulsion PSO and the distributed PSO that can help the search controller to find the optimal d - axis air gap current quickly and accurately under non-stationary operating conditions, thereby minimizing the air gap flux and then improving the motor efficiency. To verify the effectiveness and stability of this proposed algorithm, the operating efficiency of PMSM as using this proposed algorithm is compared with that of traditional search controller under non-stationary operating conditions. The results show that the proposed algorithm can improve the operating efficiency of PMSM by 6.03% on average under non-stationary operation conditions. This indicates that the search controller based on the improved PSO has a better adaptation to the variation of external operating conditions, and can improve the operation efficiency of PMSM under non-stationary condition