National Taiwan Normal University

About: National Taiwan Normal University is a education organization based out in Taipei, Taiwan. It is known for research contribution in the topics: Population & Educational technology. The organization has 9684 authors who have published 13922 publications receiving 239633 citations. The organization is also known as: NTNU.

Berry phase effects on electronic properties

Abstract: Ever since its discovery, the Berry phase has permeated through all branches of physics. Over the last three decades, it was gradually realized that the Berry phase of the electronic wave function can have a profound effect on material properties and is responsible for a spectrum of phenomena, such as ferroelectricity, orbital magnetism, various (quantum/anomalous/spin) Hall effects, and quantum charge pumping. This progress is summarized in a pedagogical manner in this review. We start with a brief summary of necessary background, followed by a detailed discussion of the Berry phase effect in a variety of solid state applications. A common thread of the review is the semiclassical formulation of electron dynamics, which is a versatile tool in the study of electron dynamics in the presence of electromagnetic fields and more general perturbations. Finally, we demonstrate a re-quantization method that converts a semiclassical theory to an effective quantum theory. It is clear that the Berry phase should be added as a basic ingredient to our understanding of basic material properties.

An ultrafast rechargeable aluminium-ion battery

Abstract: An aluminium-ion battery is reported that can charge within one minute, and offers improved cycle life compared to previous devices; it operates through the electrochemical deposition and dissolution of aluminium at the anode, and the intercalation/de-intercalation of chloroaluminate anions into a novel graphitic-foam cathode. The low cost and useful electrical properties of aluminium suggest that rechargeable Al-ion batteries could offer viable and safe battery technology, but problems with cathode materials, poor cycling performance and other complications have persisted. Here Hongjie Dai and colleagues describe an Al-ion battery that can charge within one minute and offers substantially improved cycle life with little decay in capacity compared to previous devices reported in the literature. The battery operates through the electrochemical deposition and dissolution of Al and intercalation/de-intercalation of chloroaluminate anions into a novel 3D graphitic foam cathode using a non-flammable ionic liquid electrolyte. The development of new rechargeable battery systems could fuel various energy applications, from personal electronics to grid storage1,2. Rechargeable aluminium-based batteries offer the possibilities of low cost and low flammability, together with three-electron-redox properties leading to high capacity3. However, research efforts over the past 30 years have encountered numerous problems, such as cathode material disintegration4, low cell discharge voltage (about 0.55 volts; ref. 5), capacitive behaviour without discharge voltage plateaus (1.1–0.2 volts6 or 1.8–0.8 volts7) and insufficient cycle life (less than 100 cycles) with rapid capacity decay (by 26–85 per cent over 100 cycles)4,5,6,7. Here we present a rechargeable aluminium battery with high-rate capability that uses an aluminium metal anode and a three-dimensional graphitic-foam cathode. The battery operates through the electrochemical deposition and dissolution of aluminium at the anode, and intercalation/de-intercalation of chloroaluminate anions in the graphite, using a non-flammable ionic liquid electrolyte. The cell exhibits well-defined discharge voltage plateaus near 2 volts, a specific capacity of about 70 mA h g–1 and a Coulombic efficiency of approximately 98 per cent. The cathode was found to enable fast anion diffusion and intercalation, affording charging times of around one minute with a current density of ~4,000 mA g–1 (equivalent to ~3,000 W kg–1), and to withstand more than 7,500 cycles without capacity decay.

Multicenter Analysis of Glucocerebrosidase Mutations in Parkinson's Disease

Abstract: Background Recent studies indicate an increased frequency of mutations in the gene encoding glucocerebrosidase (GBA), a deficiency of which causes Gaucher's disease, among patients with Parkinson's disease. We aimed to ascertain the frequency of GBA mutations in an ethnically diverse group of patients with Parkinson's disease. Methods Sixteen centers participated in our international, collaborative study: five from the Americas, six from Europe, two from Israel, and three from Asia. Each center genotyped a standard DNA panel to permit comparison of the genotyping results across centers. Genotypes and phenotypic data from a total of 5691 patients with Parkinson's disease (780 Ashkenazi Jews) and 4898 controls (387 Ashkenazi Jews) were analyzed, with multivariate logistic-regression models and the Mantel–Haenszel procedure used to estimate odds ratios across centers. Results All 16 centers could detect two GBA mutations, L444P and N370S. Among Ashkenazi Jewish subjects, either mutation was found in 15% of p...

Current status, opportunities and challenges of augmented reality in education

Abstract: Although augmented reality (AR) has gained much research attention in recent years, the term AR was given different meanings by varying researchers. In this article, we first provide an overview of definitions, taxonomies, and technologies of AR. We argue that viewing AR as a concept rather than a type of technology would be more productive for educators, researchers, and designers. Then we identify certain features and affordances of AR systems and applications. Yet, these compelling features may not be unique to AR applications and can be found in other technological systems or learning environments (e.g., ubiquitous and mobile learning environments). The instructional approach adopted by an AR system and the alignment among technology design, instructional approach, and learning experiences may be more important. Thus, we classify three categories of instructional approaches that emphasize the ''roles,'' ''tasks,'' and ''locations,'' and discuss what and how different categories of AR approaches may help students learn. While AR offers new learning opportunities, it also creates new challenges for educators. We outline technological, pedagogical, learning issues related to the implementation of AR in education. For example, students in AR environments may be cognitively overloaded by the large amount of information they encounter, the multiple technological devices they are required to use, and the complex tasks they have to complete. This article provides possible solutions for some of the challenges and suggests topics and issues for future research.