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A MEMS-based humidity sensor is proposed comprising thiol-coated gold nanoparticles (AuNPs) deposited on a glass substrate with aluminum interdigitated electrodes (IDEs). In the proposed device, the humidity is measured by monitoring the change in the device resistance as the water molecules are absorbed by the AuNPs. A highly sensitive sensing performance is obtained as a result of the large surface...
Capillary electrophoresis (CE) has been used in a number of bio-analytical detection in the past decays [1]. This detection scheme has high separation efficiency and rapid detection capability. Fluorescence detection is the most common adopted method in capillary electrophoresis system. However, fluorescence detection approach relies on fluorescence labeling and delicate optical excitation and detection...
This study presents design and fabrication of an electromagnetic pump for microfluidic applications. The pump comprises four major components, namely a lower glass plate containing a copper microcoil, a middle PMMA plate incorporating a PDMS diaphragm with a surface-mounted magnet, upper PMMA channel plates, and a ball-type check valve located at the channel inlet. When an AC current is passed through...
In the study, a novel gas sensor is presented for detection of aromatic hydrocarbons (benzene, toluene and xylene), consisting of a quartz substrate, Pt electrodes and a WO3 thin film. Oxidation occurs on the heated WO3 sensing layer as an aromatic hydrocarbon is present in the atmosphere, which causes a resistance variation of the WO3 thin film. From the measured resistance change, the aromatic hydrocarbon...
This paper presents a microfluidic flow sensor for the detections of velocity and viscosity, especially for ultra-low viscosity applications. An etched optic fiber with the diameter of 9 mm is embedded in a microfluidic chip to couple laser light into the microfluidic channel. An flow induced vibration causes periodic flapping motion of the optic fiber cantilever. Through the frequency analysis, the...
In the study, a novel micro sensor is presented for detection of measurement of electrical current, consisting of a quartz substrate and Pt resistors. As current flow through the resistor, some energy is converted to heat. The power generated in this process is related to both the voltage across the resistor and the current flowing through it, which causes a resistance variation of the resistance...
Micro flow cytometer has been widely used for counting and identifying individual cells. This study presents a novel microfluidic device for arranging cells/particles to a single file in the vertical direction for obtaining a great spatial resolution of signal detection in a micro-flow cytometric chip. Using the isotropic wet etching process and the photomask design, a sequence of micro-weir structures...
This paper presents a novel yet high performance diascopic illumination configuration for simultaneously detecting cells of different sizes and different fluorescence labeling in a microfluidic chip. An objective-type dark-field condenser equipped with a low-cost tungsten bulb light source with continuous wavelengths (400 to 900 nm) and an UV-Vis-NIR spectrometer is used for detecting the multispectral...
A high-performance MEMS-based gas chromatography (GC) device is proposed comprising a miniature serpentine column with dimensions of 3.2 m × 200 μm × 250 μm (length × width × depth) and an integrated Pt micro-heater. The column is fabricated on a Si die measuring 3.5 × 1.8 mm2 using a wet etching process and is bonded to a Pyrex cover plate incorporating the Pt micro-heater via a thermal fusion process...
This study proposed a high performance microfluidic rectifier utilizing self-induced virtual valves in a sudden expansion channel. An embedded block structure is used to enhance the formation of vortices at the sudden expansion channel. The effective hydraulic diameter of the microchannel is reduced due to the formation of the vortices and it hence increases the flow resistance of the microchannel...
This paper presents a dynamic simulation model for a hybrid electric scooter (HES) designed by NPUST in Taiwan. The HES is built in a parallel hybrid configuration with a 24 V 370 W auxiliary power electric motor, a 24 V 600 W generator, a 24 V 15 AH battery, and an electronically controlled fuel injection internal combustion engine (ICE). Because the system is complex and nonlinear in nature, the...
This paper presents a simple method to enhance the separation efficiency of DNA biosamples in a chip-based capillary electrophoresis system utilizing high-voltage pulsed DC electric fields. Since the average power consumption is reduced by the pulse electric fields, the Joule heating effect is significantly reduced. The experimental and numerical investigations commence by separating a mixed sample...
The purpose of this paper is to apply characteristics of residual stress that causes cantilever beams to bend for manufacturing a micro-structured gas flow sensor. This study uses a silicon wafer deposited silicon nitride layers, reassembled the gas flow sensor with four cantilever beams that perpendicular to each other and manufactured piezoresistive structure on each micro-cantilever by MEMS technologies,...
This paper presents a novel microfabricated formaldehyde gas sensor with enhanced sensitivity and detection resolution capabilities. The device comprises a silica microstructure suspended at a small distance above a glass substrate. A sputtered NiO thin film is used as the formaldehyde sensing layer. The gas sensor incorporates Pt heating resistors integrated with a micro hotplate to provide a heating...
This study exploits a bending-up cantilever caused by residual stress to manufacture a micro gas flow sensor. MEMS techniques are used to deposit a silicon nitride layer on a silicon wafer to create a piezoresistive structure. A platinum layer is deposited on the silicon nitride layer to form a resistor and the structure is then etched to form a freestanding micro-cantilever. When an airflow passes...
This paper presents a novel method for continuous particle sorting and collection by using of cascade squeeze-jumping effect under microfluidic configuration. Microparticles with different sizes can be successfully separated at different stages of squeezed sheath flows. Separated microparticles then flow into expansion channel blocks to enlarge the distance of the separated flow streams and are collected...
This paper presents an experimental and numerical investigation into the use of high-resolution injection techniques to separate DNA fragments within electrophoresis microchips. The study addresses the principal material transport mechanisms such as electrokinetic migration, fluid flow, diffusion, variable-volume injection methods, and gives detail analyses to the double-L injection technique, which...
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