Publications by authors named "Pinghei Chen"

In this study, pool-boiling heat-transfer experiments were performed to investigate the effect of the number of interlines and the orientation of the hybrid wettable pattern. Hybrid wettable patterns were produced by coating superhydrophilic SiO2 on a masked, hydrophobic, cylindrical copper surface. Using de-ionized (DI) water as the working fluid, pool-boiling heat-transfer studies were conducted on the different surface-treated copper cylinders of a 25-mm diameter and a 40-mm length.

View Article and Find Full Text PDF

A Lego-like swappable fluidic module (SFM) is proposed in this research. We designed and fabricated selected modular fluidic components, including functional and auxiliary types that can be effortlessly swapped and integrated into a variety of modular devices to rapidly assemble a fully-portable, disposable fluidic system. In practice, an integrated SFM uses finger-operated, electricity-free pumps to deliver fluids.

View Article and Find Full Text PDF

The recent and continuing epidemic of enterovirus 71 in China has affected millions of children and resulted in thousands of deaths. Timely diagnosis and management is essential for disease control. Current enterovirus 71 molecular tests require resources that are unavailable for on-site testing.

View Article and Find Full Text PDF

Objectives: We have developed a one-step nucleic acid dipstick assay (NADA) for visually detecting polymerase chain reaction (PCR) products within 3min. "One-step" means that there were no additional procedures between amplification and detection.

Methods: This method was achieved through the use of asymmetric PCR and specially designed probes with appropriate melting temperature values.

View Article and Find Full Text PDF

This research reports the design, analysis, integration, and test of a prototype of a real-time convective polymerase chain reaction (RT-cPCR) machine that uses a color charged coupled device (CCD) for detecting the emission of fluorescence intensity from an RT-cPCR mix in a microliter volume glass capillary. Because of its simple mechanism, DNA amplification involves employing the cPCR technique with no need for thermocycling control. The flow pattern and temperature distribution can greatly affect the cPCR process in the capillary tube, a computational fluid dynamics (CFD) simulation was conducted in this study for the first time to estimate the required period of an RT-cPCR cycle.

View Article and Find Full Text PDF

This study investigated the pool boiling heat transfer under heating surfaces with various interlaced wettability. Nano-silica particles were used as the coating element to vary the interlaced wettability of the surface. The experimental results revealed that when the wettability of a surface is uniform, the critical heat flux increases with the more wettable surface; however, when the wettability of a surface is modified interlacedly, regardless of whether the modified region becomes more hydrophilic or hydrophobic, the critical heat flux is consistently higher than that of the isotropic surface.

View Article and Find Full Text PDF

This study developed portable, non-invasive flexible humidity and temperature microsensors and an in situ wireless sensing system for a proton exchange membrane fuel cell (PEMFC). The system integrated three parts: a flexible capacitive humidity microsensor, a flexible resistive temperature microsensor, and a radio frequency (RF) module for signal transmission. The results show that the capacitive humidity microsensor has a high sensitivity of 0.

View Article and Find Full Text PDF

This study utilized the radio frequency (RF) technology to develop a multilayered polymeric DNA sensor with the help of gold and magnetic nanoparticles. The flexible polymeric materials, poly (p-xylylene) (Parylene) and polyethylene naphtholate (PEN), were used as substrates to replace the conventional rigid substrates such as glass and silicon wafers. The multilayered polymeric RF biosensor, including the two polymer layers and two copper transmission structure layers, was developed to reduce the total sensor size and further enhance the sensitivity of the biochip in the RF DNA detection.

View Article and Find Full Text PDF

The present study aims to investigate the effect of suspended nanoparticles in base fluids, namely nanofluids, on the thermal resistance of a disk-shaped miniature heat pipe [DMHP]. In this study, two types of nanoparticles, gold and carbon, in aqueous solution are used respectively. An experimental system was set up to measure the thermal resistance of the DMHP with both nanofluids and deionized [DI] water as the working medium.

View Article and Find Full Text PDF

This study investigated a simple model of transformers that have liquid magnetic cores with different concentrations of ferro-nanofluids. The simple model was built on a capillary by enamel-insulated wires and with ferro-nanofluid loaded in the capillary. The ferro-nanofluid was fabricated by a chemical co-precipitation method.

View Article and Find Full Text PDF

An on-chip transformer with a ferrofluid magnetic core has been developed and tested. The transformer consists of solenoid-type coil and a magnetic core of ferrofluid, with the former fabricated by MEMS technology and the latter by a chemical co-precipitation method. The performance of the MEMS transformer with a ferrofluid magnetic core was measured and simulated with frequencies ranging from 100 kHz to 100 MHz.

View Article and Find Full Text PDF

A new micromachined circulating polymerase chain reaction (PCR) chip is reported in this study. A novel liquid transportation mechanism utilizing a suction-type membrane and three microvalves were used to create a new microfluidic control module to rapidly transport the DNA samples and PCR reagents around three bio-reactors operating at three different temperatures. When operating at a membrane actuation frequency of 14.

View Article and Find Full Text PDF

This study presents a novel method for DNA detection with multi-layer AuNPs to enhance overall detection sensitivity. This essay achieves not only an innovative radio-frequency biosensor but also a critical signal amplification methodology. Results show that bandwidth change for multi-layer AuNP with hybridization of DNA exceeds that for the double-layer AuNP up to 0.

View Article and Find Full Text PDF

This paper presents a flexible wetness sensor whose detection signal, converted to a binary code, is transmitted through radio-frequency (RF) waves from a radio-frequency identification integrated circuit (RFID IC) to a remote reader. The flexible sensor, with a fixed operating frequency of 13.56 MHz, contains a RFID IC and a sensor circuit that is fabricated on a flexible printed circuit board (FPCB) using a Micro-Electro-Mechanical-System (MEMS) process.

View Article and Find Full Text PDF

The present study describes an ultrasensitive protein biochip that employs nanogap electrodes and self-assembled nanoparticles to electrically detect protein. A bio-barcode DNA technique amplifies the concentration of target antigen at least 100-fold. This technique requires the establishment of conjugate magnetic nanoparticles (MNPs) and gold nanoparticles (AuNPs) through binding between monoclonal antibodies (2B2), the target antigen, and polyclonal antibodies (GP).

View Article and Find Full Text PDF