Ping-hei Chen

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Papers by Ping-hei Chen

Saturated Pool Boiling of Novec-7100 Dielectric Liquid Over Microgroove Surfaces with Anisotropic Wettability Characteristics

Effects of wide-range copper surface wettability on spray cooling heat transfer

Experimental Thermal and Fluid Science, May 1, 2023

Ring droplet formation during evaporation of a sessile water droplet on a biphilic surface

International Journal of Heat and Mass Transfer, 2022

Ultrasensitive Electrical DNA Identification with Bio-Bar-Code DNA and Nanoparticles in Nanogap Device

An electrical detection method for an ultrasensitive approach to identify DNA strands with self-a... more An electrical detection method for an ultrasensitive approach to identify DNA strands with self-assembled multilayer gold nanoparticles (AuNPs) in nanogap device is presented. This approach provides high selectivity with sensitivity that can be comparable to nanogap sensing on-chip system without the need of polymerase chain reaction (PCR) amplification. The concentration of target DNA is amplified at least 100 folds utilizing bio-bar-code DNA approach which is a pseudo-homogeneous system with two nanoparticle-based solutions including magnetic/gold nanoparticles (MNPs/AuNPs). This study indicates that lower concentration of the probes can be used very efficiently to bind target DNA, thereby reducing time required for DNA sensing. The nanogap devices for DNA identification are fabricated by electron-beam lithography (EBL). The concept for electrical detection of biological molecular interaction herein will be an excellent dynamic range and ideally set up for multiplexing in the future. Based on bio-bar-code DNA amplification (BCA) detection technique, the target DNA can be detected the concentration even lower than femto-molar range.

Numerical study of effects of slip boundaries on 2D Rayleigh-Benard convection using lattice Boltzmann method

Classification of Surface Wettability and Mircro/Nano-Fabrication Methods in Surface Modification: A Review

Evaporation heat transfer enhancement by a laser-textured heterogeneous surface

Colloids and Surfaces A: Physicochemical and Engineering Aspects, Nov 1, 2021

Abstract Numerous studies have explored the influence of surface wettability on liquid vapor heat... more Abstract Numerous studies have explored the influence of surface wettability on liquid vapor heat transfer through surface modification; especially when the surface can be modified with heterogeneous wettability. Herein the heterogeneous wettability surfaces with the designated patterns can be created on surfaces only in a few seconds after laser irradiation. LSCM images indicated the surfaces with laser irradiation became rougher and provided more nucleation sites. In this study, experiments for evaporation behaviors of water droplet were performed on picosecond laser-textured heterogeneous copper surfaces. The CCD images revealed that bubble dynamics play an important role in droplet evaporation on heated surfaces. Based on the behavior of bubble coalescence and departure, the heterogeneous laser-textured surface exhibited superior evaporation efficiency.

Role of amoxicillin functionalised Fe<SUB align="right">3O<SUB align="right">4 on the settling velocity of starch

International Journal of Nanoparticles, 2015

Amoxicillin functionalised ferrite nanoparticle was synthesised by co-precipitation method under ... more Amoxicillin functionalised ferrite nanoparticle was synthesised by co-precipitation method under nitrogen atmosphere. Thus obtained black coloured product was characterised by Fourier transform infrared (FTIR) spectroscopy, UV-visible spectroscopy, X-ray diffraction (XRD), particle size analysis (PSA), scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM) and vibrating sample measurement (VSM) techniques. The sedimentation velocity of starch in the presence of amoxicillin functionalised ferrite was carried out at three different pH values namely 2.5, 7.1 and 12.0. The influence of amoxicillin functionalised ferrite on the sedimentation velocity of starch was evaluated with the help of FTIR, SEM, VSM, UV-visible, fluorescence spectroscopy. We noted an important observation that Starch-Fe3O4-amoxicillin system exhibited the lowest VSM value than the Fe3O4-amoxicillin system.

Synthesis and characterization of fluorescent bio-degradable Poly (ε-Caprolactone)

International Journal of Plastics Technology, May 23, 2014

Ring opening polymerization (ROP) of ε-caprolactone (C.L.) was carried out at 160 °C under nitrog... more Ring opening polymerization (ROP) of ε-caprolactone (C.L.) was carried out at 160 °C under nitrogen atmosphere for 2 hours with mild stirring condition by bulk polymerization method and by using stannous octoate (S.O.) as a catalyst in the presence of Bromophenolblue (BPB) as a chemical initiator. Thus obtained BPB end capped poly (Caprolactone) (PCL) was characterized by Fourier Transform Infrared (FTIR) spectroscopy, Nuclear magnetic resonance (NMR) spectroscopy, differential scanning calorimetry (DSC), contact angle measurement, scanning electron microscopy (SEM) and gel permeation chromatography (GPC) like analytical tools.

Roughness and wettability properties of plain and silica-coated copper surfaces textured with picosecond laser

Applied Surface Science, Jun 1, 2020

Abstract Many recent studies have investigated the mechanism of wettability transition of laser-t... more Abstract Many recent studies have investigated the mechanism of wettability transition of laser-textured copper surfaces on different materials. Furthermore, several such studies have focused on approaches to accelerate wettability transition from hydrophilicity to hydrophobicity, such as temperature annealing and the use of chemical solutions. However, few researchers have focused on maintaining the initial hydrophilicity of laser-textured surfaces. This study presents a hybrid surface modification method involving chemical bath deposition and ultrafast laser. First, the selected copper substrates are modified using the sol-gel method through dip coating. Subsequently, the coated copper surfaces are irradiated with a picosecond laser. After laser texturing, bumpy structures are formed, and SiO2 nanoparticles can be sintered on the surfaces. Thus, the original hydrophilicity can be maintained, and the surface roughness can be enhanced simultaneously. By using this hybrid modification method, a heterogeneous surface with high-precision patterns can be obtained. Moreover, the mechanism of wettability transition of laser-textured copper surfaces with different laser fluences is discussed using the Wenzel and Cassie Baxter wetting model by analyzing the chemical composition and surface morphology of the treated surfaces.

Effect of biomimetic fishbone-patterned copper tubes on pool boiling heat transfer

International Journal of Heat and Mass Transfer, Dec 1, 2020

Abstract The effect of laser-textured copper surfaces on pool boiling heat transfer in copper tub... more Abstract The effect of laser-textured copper surfaces on pool boiling heat transfer in copper tubes was experimentally investigated by using deionized water as a working fluid under ambient environmental conditions. The picosecond laser system was used to apply fishbone patterns on cylindrical copper surfaces. All pool boiling experiments were performed using a saturated working fluid, and the heat flux was up to 426 kW/m2 in these experiments. The heat transfer coefficient of laser-textured dense fishbone sample exhibited a factor up to 1.12 at the highest evaluated heat flux. Bubble dynamics were studied using images recorded using high-speed cameras under different heat flux regimes. In addition, the effect of laser-textured surfaces on the temperature distribution during pool boiling along cylindrical surfaces was analyzed.

Development of Optically-Induced-Dielectrophoresis (Odep)-Based Virtual Cell Microfilters in a Microfluidic Chip for the Isolation of Circulating Tumor Cell (CTC) Clusters

Local mass (heat) transfer distribution over the concave surface of a turbine blade

Journal of the Chinese Society of Mechanical Engineers, Transactions of the Chinese Institute of Engineers, Series C/Chung-Kuo Chi Hsueh Kung Ch'eng Hsuebo Pao, Apr 1, 1990

Effects of Compound Angle Injection on Flat-Plate Film Cooling Through a Row of Conical Holes

This paper presents the measured heat transfer and film cooling results over a flat plate as the ... more This paper presents the measured heat transfer and film cooling results over a flat plate as the secondary flow is ejected into the mainstream through a row of conical holes. A transient liquid crystal thermography was employed to derive the film cooling performance and heat transfer distribution over the test flat plate. Each conical injection hole, with a pitch-to-diameter ratio of 3 on the exit plane, had an expanded angle of 8 degrees. The effects of changing the spanwise injection angles and blowing ratios on both film cooling and heat transfer distributions were investigated. Test pieces in this study used different spanwise injection angles of 13 = 0°, 45°, and 90° but maintained the same inclination angle of y = 35°. For each test piece, four different blowing ratios of 0.5, 1.0, 1.25 and 1.5 were tested at Re = 44,000, Tu = 2.3%, 51/d 0.22, pld = 3, and R = 1.06. A baseline check was also conducted for the fiat-plate film cooling through the use of straight circular holes. In addition, a comparison was made between the film cooling results using conical holes with those using straight circular holes. Measured results showed that the laterally averaged heat transfer coefficient increases with the blowing ratio for both straight circular and conical hole configurations. For the simple injection, a conical configuration was found to have better film cooling protection only at higher blowing ratio (M = 1.25 and 1.5). Compound angle injection does not have specific advantage for the film cooling protection in the case of conical configuration.

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Effects of Wide-Range Copper Surface Wettability on Spray Cooling Heat Transfer

Social Science Research Network, 2022

Development of a Novel Real-Time PCR Machine

A novel multi-channel detection system for real-time PCR machine is proposed in this study. The p... more A novel multi-channel detection system for real-time PCR machine is proposed in this study. The prototype in this article is equipped with a spectrometer which has the bandwidth of visible light, hence there are more than 6 channels can be detected simultaneously. In contrast to the traditional Real-Time PCR machine with discrete fluorescence wavelength detection channels, the prototype is equipped with continuous fluorescence wavelength detecting ability to multiplex Real-Time PCR. In this study, a HBV DNA template with LC-Red 640 dye and the Internal Control DNA template with LC-Red 705 dye were employed for DNA quantification experiments. The results show that this prototype provides comparable accuracy and reproducibility as the commercial system for DNA quantification with the DNA quantification and detection method proposed in this study.