The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Commonly, microelectrodes used in microfluidics are made from copper, Au or Pt. They are difficult to fabricate and the cost is relatively high. Thus, we designed and fabricated a novel microelectrode made from silicon for it is cheap and easy to fabricate. It has been proven that cells can be manipulated by dielectrophoresis force producing on interdigitated electrodes. In addition, the direction...
In this work, we present novel designs of herringbone-type chaotic mixers which can effectively induce more transverse movement of flows and thus increase mixing performance. The original design of the herringbone-type chaotic mixer was proposed by Stroock et al. The major advantages of the chaotic mixer are the simplicities in device fabrication (i.e., simple geometry) and operation (i.e., passive...
An amperometric biosensor based on Prussian blue (PB) modified indium tin oxide (ITO) electrode was developed. The roughness of PB film which affects the electrocatalytic properties of PB film was controlled by varying deposition voltage and time. Atomic force microscopy (AFM) was used to measure the roughness of PB films deposited under various conditions. We used capillary electrophoresis (CE) method...
In this paper we present a novel sample injection chip. Microvalves and microchannels are integrated on the chip. The valve is a passive lowpass valve that allows a liquid flow at a low flow rate and prohibits it when the flow rate exceeds a threshold. We can control the injection volume by changing the channel design. The chip consists of a channel substrate, an upper valve substrate and an under...
A power-free method is explored to perform mixing in a microchannel without any external active mechanisms such as pumps, valves, or external energies like electrostatic, or magnetic fields. The proposed mixing device is power-free in the sense that the surface tension is the only force that transports, merges, mixes, and stops the liquid. It is cost-effective that the channel has no sidewalls with...
The micro-flow systems have been extensively introduced into the micro-devices in Microelectromechanical System(MEMS), and the flowing characteristics determines the performance of the micro-devices to a great extent. Here, the experiments of characteristics of distilled water flow in a series of round quartz microchannels with the diameters of 13mum, 20mum and the lengths ranging from 40 mm to 100...
The CO2 bubbles clogging in anode flow field is a vital problem in development of liquid feed micro direct methanol fuel cells (μDMFC). In order to study the CO2 bubbles clogging behavior, an air-breathing transparent μDMFC with 180 μm wide serpentine channels in anode was fabricated. In situ visual investigation of the bubbles behavior in anode flow field was implemented on the microfluidics test...
In this work, the transportation of nano-particles inside micro-channels with nano-sized gaps and various geometries is investigated. Numerical simulations based on fluid governing equations in Eulerian coordinate and particle motion equations in Lagrangian coordinate are employed and the effects caused by parameters including curvature and branching angle of micro-channel, nano-gap size, and the...
The plug-like fluidic profile is one of most advantages of electroosmotic flow, which influences the reproducibility, sensitivity and separation efficiency of the microfluidic devices. Electroosmotic flow in microchannels with hydraulic diameters of less than 20 microns are investigated experimentally and qualitatively compared with prediction in electric double layer (EDL) theory. Fluidic profiles...
5SPE (Solid phase extraction) method, which is compatible with MEMS (micro-electro-mechanical system) technology, has proven efficient and amenable to microfluidic chips. An SPE microfluidic chip for DNA extraction by using porous silicon dioxide as the solid phase matrix has been developed. Porous matrix coated on the wall of the channel in the microfluidic chip to provide a surface-enlarging matrix,...
We present the successful design and fabrication of push-and-pull micro-valve and micro mixer chips that driven by a kind of nanoparticle based giant electrorheological fluid (GER fluid). Our multilayer chips are fabricated by polydimethylsiloxane (PDMS)-based soft lithography techniques. Fast response time of the GER fluid and the push-and-pull valve design adopted assure fast switching time of the...
In this paper, flow control of nano fountain pen using active membrane pumping is investigated. DPN (Dip Pen Nano- Lithography) has a shortcoming in which is the need of frequent loading and unloading while coating for broadband patterning. This issue is caused by a limit in quantity of ink, which is tied on the tip surface. The control of fluid injection using active membrane pumping in chambers...
A thermal microsystem, integrated with pressure and temperature microsensors, is fabricated to study convective boiling under nearly uniform heat flux boundary condition. The temperature and pressure distribution along the microchannel is measured correspondingly. The pressure increases with input power when two phase flow develops. A pressure peak appears at the location of liquid-vapor interface...
In this paper steady electro-osmotic flow (EOF) in cross-straight channel is measured by micro particle image velocimetry (micro-PIV). Micro channels with two elementary configurations, a straight channel and a cross-straight channel, are fabricated by wet chemical etching process on glass. The uniform Zeta potential is obtained form the ratio of averaged velocities of EOF in the straight channel...
The design and fabrication for a novel silicon-based micro direct methanol fuel cell (mu-DMFC) of 0.64cm2 active area on <100> silicon wafer are described in this paper. The novelty of the DMFC structure is that the anodic micro channels arranged in the asymmetric mesh have been fabricated, and the first objective of the experimental trials is to verify the feasibility of the novel structure...
A novel passive micromixer with rapid mixing and low pressure drop has been successfully demonstrated by simulations and micro-fabrication. The structure of this micro-mixer contains one main channel, two sub-channels for injecting the other specie and some baffles in the main channel to form mixing chambers. Adding baffles to the main channel will produce the recirculation to increase the contact...
Pressure drop is important in performance of MEMS devices with microchannel. The geometry of microchannel will have important significant effect on of pressure drop and friction factor. The effect of four cross section shapes of microchannel on friction factors is investigated. It is found that the friction factors are significantly affected by the cross section shape. The four cross section shapes...
Rapid technological progress has required reliable measurement techniques for velocity field in microspace, particularly in the biochip or electrochemical engineering. Research on the flow in microchannel is the foundation of the microfluidic-based biochip. In this paper, a micro-resolution particle image velocimetry (mu-PIV) system, with order of 1 mum spatial resolution for the measurement of velocity...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.