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.

Fabrication methods for auxetic foams

Abstract: Auxetic materials have a negative Poisson's ratio, that is, they expand laterally when stretched longitudinally. Negative Poisson's ratio is an unusual property that affects many of the mechanical properties of the material, such as indentation resistance, compression, shear stiffness, and certain aspects of the dynamic performance. The unusual mechanical properties of auxetic foams are attributed to the deformation characteristics of re-entrant microstructures. One way of obtaining negative Poisson's ratio is by using a re-entrant cell structure. Auxetic foam was fabricated from a conventional polymeric foam. The fabrication method for making both small and large auxetic foam specimens is described.

Rectenna Application of Miniaturized Implantable Antenna Design for Triple-Band Biotelemetry Communication

Abstract: A novel antenna design that effectively covers three bands (the medical implant communications service (MICS) band at 402 MHz, and the industrial, scientific, and medical (ISM) band at 433 MHz and 2.45 GHz) using a π-shaped radiator with a stacked and spiral structure is described. The antenna has compact size of 254 mm 3 (10 mm by 10 mm by 2.54 mm). The proposed design is effective for triple-band biotelemetry with data telemetry (402 MHz), wireless powering transmission (433 MHz), and wake-up controller (2.45 GHz). An experimental prototype of the compact stacked rectenna was fabricated on a Roger 3210 substrate. This antenna was used in a rectenna (rectifying antenna) for 433 MHz wireless powering transmission, and provided a conversion efficiency of 86% when 11 dBm microwave power was received at 433 MHz with a 5 kΩ load. The optimal antenna was fabricated and tested in a minced front leg of pork. The simulated and measured bandwidths were 86 MHz and 113 MHz in the MICS band, and 60 MHz and 70 MHz in the ISM band, respectively.

The influencing factors of commitment and business integration on supply chain management

Abstract: The main purpose of this study focuses on how to integrate the supply chain management business process. There were a total of 600 questionnaires issued in this study with 134 valid questionnaires being retrieved. The study concludes the following results: the level of idiosyncratic investments to supply chain partners, the degree of dependence between supply chain partners, and the level of product salability of manufacturer would enhance commitment and, consequently, the integration of the SCM business process. The degree of trust, power, continuity, and communication between supply chain partners would enhance commitment and, consequently, the integration of the SCM business process. The level of affective commitment, continuance commitment, and normative commitment of supply chain partners would be helpful in the integration of the SCM business process.

Analysis and Implementation of a Novel Bidirectional DC–DC Converter

Abstract: A novel bidirectional dc-dc converter is presented in this paper The circuit configuration of the proposed converter is very simple The proposed converter employs a coupled inductor with same winding turns in the primary and secondary sides In step-up mode, the primary and secondary windings of the coupled inductor are operated in parallel charge and series discharge to achieve high step-up voltage gain In step-down mode, the primary and secondary windings of the coupled inductor are operated in series charge and parallel discharge to achieve high step-down voltage gain Thus, the proposed converter has higher step-up and step-down voltage gains than the conventional bidirectional dc-dc boost/buck converter Under same electric specifications for the proposed converter and the conventional bidirectional boost/buck converter, the average value of the switch current in the proposed converter is less than the conventional bidirectional boost/buck converter The operating principle and steady-state analysis are discussed in detail Finally, a 14/42-V prototype circuit is implemented to verify the performance for the automobile dual-battery system

An Accurate Tag Estimate Method for Improving the Performance of an RFID Anticollision Algorithm Based on Dynamic Frame Length ALOHA

Abstract: In a radio-frequency identification (RFID) system, the dynamic frame length ALOHA protocol is widely adopted to solve the anticollision problem. Analysis for the anticollision problem can be divided into two primary parts. The concern of the first part is how to precisely estimate the number of tags. The other part involves determination of dynamic frame length to achieve maximum throughput or channel usage efficiency. In this paper, we present an accurate method for estimating tag quantity. This method is based on the maximum a posteriori probability decision. We also derive the optimal frame length using radio channel efficiency. Simulation results indicate the tag estimate error of the proposed method is less than 4%. Use of our proposed tag estimate method together with optimal frame length can achieve close to the theoretical maximum throughput of the framed ALOHA algorithm.