National Cheng Kung University

About: National Cheng Kung University is a education organization based out in Tainan City, Taiwan. It is known for research contribution in the topics: Population & Thin film. The organization has 49723 authors who have published 69799 publications receiving 1437420 citations. The organization is also known as: NCKU.

Formaldehyde Gas Sensors: A Review

Abstract: Many methods based on spectrophotometric, fluorometric, piezoresistive, amperometric or conductive measurements have been proposed for detecting the concentration of formaldehyde in air. However, conventional formaldehyde measurement systems are bulky and expensive and require the services of highly-trained operators. Accordingly, the emergence of sophisticated technologies in recent years has prompted the development of many microscale gaseous formaldehyde detection systems. Besides their compact size, such devices have many other advantages over their macroscale counterparts, including a real-time response, a more straightforward operation, lower power consumption, and the potential for low-cost batch production. This paper commences by providing a high level overview of the formaldehyde gas sensing field and then describes some of the more significant real-time sensors presented in the literature over the past 10 years or so.

Empowering personalized learning with an interactive e-book learning system for elementary school students

Abstract: Today various types of tablet computers are used, including iPad and Android Tablets. These individual portable digital devices can be used as e-book readers to support mobile personalized learning. Though many studies have investigated e-books by targeting undergraduate students, yet less attention has been paid to children. Therefore, an Interactive E-book Learning System (IELS) was developed for elementary school students in this study. The interactive principles in multimedia learning were adopted to empower students’ personalized learning experiences with e-books. Meanwhile, in order to meet student’s learning needs, a group of in-service teachers were consulted for acquiring their domain expertise. Personalized learning functions, such as e-annotation and bookmarks, content searching, and learning process tracking, were designed to reinforce student learning. Two investigations were conducted for evaluation of the developed system. The first investigation was conducted with 166 elementary school students to evaluate the usability and functionality of the developed system and the feedback from the students. It was found that the usability and functionality of the developed system were well-suited for most of the students. The second investigation was to evaluate the learning effect of the developed system. The results showed that using an e-book or printed book made no significant difference to the students’ reading accuracy; however, the learning process tracking technique of IELS can provide detailed logs about the actual learning processes which can be used by the system to provide further assistance to individual learner. This study concludes that such a tailor-made e-book learning system could achieve a better personalized learning experience for elementary school students.

Single-particle measurements of electrochemical kinetics in NMC and NCA cathodes for Li-ion batteries

Abstract: The electrochemical kinetics of battery electrodes at the single-particle scale are measured as a function of state-of-charge, and interpreted with the aid of concurrent transmission X-ray microscopy (TXM) of the evolving particle microstructure. An electrochemical cell operating with near-picoampere current resolution is used to characterize single secondary particles of two widely-used cathode compounds, NMC333 and NCA. Interfacial charge transfer kinetics are found to vary by two orders of magnitude with state-of-charge (SOC) in both materials, but the origin of the SOC dependence differs greatly. NCA behavior is dominated by electrochemically-induced microfracture, although thin binder coatings significantly ameliorate mechanical degradation, while NMC333 demonstrates strongly increasing interfacial reaction rates with SOC for chemical reasons. Micro-PITT is used to separate interfacial and bulk transport rates, and show that for commercially relevant particle sizes, interfacial transport is rate-limiting at low SOC, while mixed-control dominates at higher SOC. These results provide mechanistic insight into the mesoscale kinetics of ion intercalation compounds, which can guide the development of high performance rechargeable batteries.