Publications by authors named "Yoon-Suk Chang"
Methacholine bronchial provocation test provides the concentration of methacholine causing a 20% decrease in forced expiratory volume in 1 s (FEV1) from baseline (PC20). The dose-response slope (DRS), and other continuous indices of responsiveness (CIR; the percentage decline from the post-diluent baseline FEV1 after the last dose of methacholine), and per cent recovery index (PRI; the percentage increase from the maximally reduced FEV1 after bronchodilator inhalation) are alternative measures. The clinical relevance of these indices in predicting acute asthma exacerbations has not been fully evaluated.
View Article and Find Full Text PDFPiezoelectric nanogenerators (PNGs) are capable of converting energy from various mechanical sources into electric energy and have many attractive features such as continuous operation, replenishment and low cost. However, many researchers still have studied novel material synthesis and interfacial controls to improve the power production from PNGs. In this study, we report the energy conversion efficiency (ECE) of PNGs dependent on mechanical deformations such as bending and twisting.
View Article and Find Full Text PDFNew advanced composite materials have recently been of great interest. Especially, many researchers have studied on nano/micro composites based on matrix filled with nano-particles, nano-tubes, nano-wires and so forth, which have outstanding characteristics on thermal, electrical, optical, chemical and mechanical properties. Therefore, the need of numerical approach for design and development of the advanced materials has been recognized.
View Article and Find Full Text PDFA statistical study on nanoparticle movements in a microfluidic channel.
J Nanosci Nanotechnol
January 2011
Article Synopsis
- Microfluidic channels are important for controlling nanoscale objects like nanoparticles and DNA but are challenging to design due to high fabrication costs and complex experiments.
- Numerical methods can help predict the performance of these channels by addressing issues like nanowire alignment and cell adhesion, offering a more cost-effective alternative.
- This paper presents an updated immersed finite element method that simulates nanoparticle movements, examines the effects of Brownian motion under varying temperatures, and predicts improved focusing efficiency in a double lens system.
Article Synopsis
- The study focuses on simulating a nanoparticle focusing lens within a microfluidic channel to improve the selection and transfer of biomolecules, addressing challenges in nano and bioengineering.
- An advanced immersed finite element method is used to track the movement of nanoparticles, factoring in Brownian motion and the initial positions of the particles, while treating the fluid flow as an incompressible viscous medium.
- The results show that both moving and stationary nanoparticles can be effectively focused in the channel, suggesting that this numerical method could enhance microfluidic channel design for various applications in biotechnology.