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This PDF file contains the front matter associated with SPIE Proceedings Volume 7269, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.
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The aim of this project was to develop high performance polymer microfluidic chips with reduced complexity for
Electrospray Ionization Mass Spectrometry (ESI-MS) analysis. This paper presents the fabrication and testing of
developed hot embossed open channel polymer microfluidic chips for ESI-MS. Hot embossing was done using a laser
machined steel tool and an electroformed nickel tool on polystyrene (PS) and polycarbonate (PC) substrates. Stable
electrosprays were generated at microchannel exits of replicated microchips without cover using a high voltage
difference between a positive stainless steel electrode in the reservoir and a negative aluminum plate. Electrospray
parameters such as; nozzle tip distance from counter electrode, ESI onset potential and duration were investigated. For
open channel systems, the results show that the electric field for stable ES directly relates to the distance between the
channel tip and counter electrode, onset potential applied and to the flow velocity of the test solution in the
microchannel. Fluid is delivered as a result of electroosmosis due to an applied electric field and capillary action,
thereby eliminating the need for external pressure devices. From experimental results, for an open-channel of 100μm
width, 100μm depth, length 12.5mm attached to an open reservoir of diameter 2 mm, the optimum distance between the
channel exit tip and counter electrode is 1.2 mm for initiation of electrospray at voltage of ~2000 volts. The laser
machined steel tool was found to be more durable than the nickel tool for PS/PC microstructure fabrication.
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This paper presents a magnetophoretic separation method on a chip of white blood cells from blood under continuous flow.
The separation of red blood cells from the whole blood is performed using a high gradient magnetic separation method
under continuous flow to trap the particles inside the device. The device is fabricated by microfabrication technology and
enables to capture the red blood cells without the use of labelling tecniques such as magnetic beads. The method consists of
flowing diluted whole blood through a microfluidic channel where a ferromagnetic layer, subjected to a permanent
magnetic field, is located. The majority of red blood cells are trapped at the bottom of the device while the rest of the blood
is collected at the outlet. Experimental results show that an average of 95% of red blood cells are trapped in the device.
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We describe a highly computationally efficient method for calculating the topography of a thermoplastic
polymeric layer embossed with an arbitrarily patterned stamp. The approach represents the layer at the time of
embossing as a linear-elastic material, an approximation that is argued to be acceptable for the embossing of
thermoplastics in their rubbery regime. We extend the modeling approach to represent the embossing of
layers with thicknesses comparable to the characteristic dimensions of the pattern on the stamp. We present
preliminary experimental data for the embossing of such layers, and show promising agreement between
simulated and measured topographies. Where the thickness of the embossed layer is larger than the
characteristic dimensions of the pattern being embossed, the stamp-layer contact pressure exhibits peaks at
the edges of regions of contact, and material fills stamp cavities with a single central peak. In contrast, when
the layer thickness is smaller than the characteristic dimensions of the features being embossed, contact
pressures are minimal at the edges of contact regions, and material penetrates cavities with separate peaks at
their edges. These two apparently distinct modes of behavior, and mixtures of them, are well described by the
simple and general model presented here.
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Herein we report three novel methods which utilize chemical conjugated magnetic beads to purify synthetic gene from its synthesis solution and prepare the synthesized gene in suitable buffer for downstream applications. Silica-coated magnetic beads are applied for non-specific DNA purification to remove short oligonucleotides and monomers. Streptavidin conjugated magnetic beads and (dT)25 Oligo immobilized magnetic beads are introduced for specific DNA extraction. The performances of these methods are investigated and compared using gel electrophoresis. The optimal conditions for enhancing the extraction efficiency are discussed. In addition, the approach to integrate these solid-phase purification methods into microfluidic devices is presented.
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There has been considerable progress in the development of micro-fabricated systems for the field of chemical and
biological sciences. Much development has been driven by the need of miniaturized systems that allow cost-effective
and rapid processing of samples at the point of need. In this work, we investigate the application practicality of Objet
Eden500VTMPolyjet as a rapid and economical tool for multi-level microfluidic device rapid prototyping. The Polyjet is
a commercial system that utilizes ink-jet technology to print 3-dimensional structures with photopolymer materials. The
reproducing capability of the Polyjet system in term of lateral and vertical resolutions, aspect ratio and smoothness of
fabricated structures are investigated. In addition, the capability of the Polyjet is demonstrated by fabricating three
different devices including: 1) multi-level microfluidic chip for two-step gene synthesis, 2) a fluidic component for
micro/macro fluidic interfacing, and 3) PDMS-based microlens.
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A detailed characterization of PECVD to produce low stress amorphous silicon carbide (α-SiC) layers at high deposition
rate has been done and the biomedical applications of α-SiC layers are reported in this paper. By investigating different
working principles in high-frequency mode (13.56MHz) and in low frequency mode (380KHz), it is found that
deposition in high-frequency mode can achieve low stress layers at high deposition rates due to the structural rearrangement
from high HF power, rather than the ion bombardment effect from high LF power which results in high
compressive stress for α-SiC layers. Furthermore, the effects of deposition temperature, pressure and reactant gas ratios
are also investigated and then an optimal process is achieved to produce low stress α-SiC layers with high deposition
rates.
To characterize the PECVD α-SiC layers from optimized process, a series of wet etching experiments in KOH and HF
solutions have been completed. The very low etching rates of PECVD α-SiC layers in these two solutions show the good
chemical inertness and suitability for masking layers in micromachining. Moreover, cell culture tests by seeding
fibroblast NIH3T3 cells on the monocrystalline SiC, low-stress PECVD α-SiC released membranes and non-released
PECVD α-SiC films on silicon substrates have been done to check the feasibility of PECVD α-SiC layers as substrate
materials for biomedical applications. The results indicate that PECVD α-SiC layers are good for cell culturing,
especially after treated in NH4F.
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Electrical impedance properties of bulk carbon nanotube (CNT) composite electrodes have been studied to develop
chemical and biosensors. The CNTs embedded in composite electrodes were fabricated by means of traditional film
casting and electrospun nanoweb. The morphology of the bulk CNT electrode was investigated by scanning electron
microscopy (SEM) and transmission electron microscopy (TEM). Under the various amounts of buffer solution,
electrical impedance of the composite electrodes was measured by means of LCR meter. It is generally known that
electrical impedance measurement provides rapid and simple sensing mechanism. In this study, we found out that CNT
bulk composite electrodes showed good sensing properties for chemical and bio sensors.
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Nonlinear optics in fluid infiltrated air structured 'holey' fibres has attracted much research interest due to the flexibility
of infiltration materials and geometries that are possible. Equivalently to these 2D examples, planar structures with 1D
arrays of air holes can offer a complimentary platform for nonlinear optics investigations. Importantly, if these
structures can be photolithographically defined with longitudinal variations, then a rich array of periodic nonlinear
phenomena can be studied.
We present a novel planar integrated optic platform for fluid infiltration experiments. The platform consists of layers of
SU8 epoxy fabricated with 3×3 μm photolithographically defined microfluidic channels. The channel layer can be doped
with rhodamine in order to increase its refractive index to enable vertical confinement and also provides a fluorescent
trace to clearly indicate the path of the light. The air channels can be filled with fluids, such as high refractive index oil,
to act as optical waveguides in the visible range.
Our fabrication consists of spin coating and curing the SU8 lower cladding. We then spin-coat and cure the doped SU8
channel layer and pattern using conventional photolithography. In order to seal the channels with the upper cladding, an
SU8 dry film is applied using lamination techniques. The fabrication process is highly flexible and can be easily
extended to more complex waveguides like splits, mach zehnder structures. Multiple layers of fluid-infiltrated channels
are also possible.
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Many optofluidic devices rely on interfacing optical waveguides with microfluidic channels. Often it can be difficult to
realize micron scale waveguides and fluidic channels that are 100 times larger on the same platform. Further, it is often
desirable for an optical waveguide intersection to occur at the vertical centre of a fluidic channel rather than at its top or
at its bottom where the fluid is effectively stationary.
We present a platform for optofluidics which can achieve straightforward integration of large scale fluidic channels and
micron scale waveguides in the epoxy material SU8. A soft imprinting technique is used to define the optical waveguides
as a thin inverted rib core layer between two thick cladding layers. The core is doped with Rhodamine dye to increase the
refractive index and render it optically active for potential use as a lasing material. The fluidic channels are then formed
by a single exposure through the core and both claddings.
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A super-hemispherical (i.e. a truncated spherical) glass lens with gold (Au) nanoparticles was obtained using a surface
tension mold (StM) technique. Recently, surface plasmon of noble metal nanoparticle has attracted a considerable
amount of interest because it is extremely sensitive to the properties of the materials attached to its surface. On the other
hand, in the field of high-resolution microscopy, solid immersion lenses (SILs) with super-hemispherical shape have
received much attention because it is a convenient and powerful means of improving both the spatial resolution and the
light collection efficiency. A combination of the SIL and the Au nanoparticles could be very suitable for use in surface
plasmon microscopy. In this study, Na2O-CaO-SiO2 glass was heated on Au-coated glassy-carbon substrate up to 800 °C.
The obtained glasses were found to have super-hemispherical shape, and the Au nanoparticles were deposited on its
bottom planar surface. The effects of the deposition condition of Au on the distribution of Au nanoparticles and the
shape of glass were investigated, and the surface plasmon resonance absorption spectra from the obtained samples were
measured.
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This paper aims to develop an effective multiscale simulation technique for the deformation analysis of nanotube-based
nanoswitches. In the multiscale simulation, the key material parameters, (e.g., Young's modulus and moment of inertia)
are extracted from the MD simulation which can explore the atomic properties. Then, the switches are simplified to
continuum structure which is discretized and simulated by the advanced RBF meshfree formulation. The system of
equations is nonlinear because the nonlinear loading is calculated from coupled the electrostatic, the elastostatic, and the
van der Waals energy domains. Besides the normal deformation analysis, the pull-in voltage characteristics of different
nanoswitches based on the double-walled nanotubes are analyzed. Comparing with the results in the literature and from
experiments, it has proven that the developed multiscale approach is accurate and efficient.
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The effect of electron beam dose and low accelerating voltage on diamond-like-carbon (DLC) deposition rate and the resulting current-voltage characteristics in thin metal/DLC/semiconductor junctions was studied. We show that thicker DLC films can be obtained using lower accelerating voltages (2 kV) than when using higher accelerating voltage (20 kV). However, under the conditions used the insulating performance of the thicker films is worse than the thinner films. We attribute this effect to the variation of tunnelling barrier height in DLC deposited using different accelerating voltages. DLC films with a tunnelling barrier height of up to 3.12 eV were obtained using a 20 kV electron-beam, while only 0.73 eV was achieved for 2 kV DLC films.
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This paper presents a solution for the deposition of thick amorphous silicon (α-Si:H) in plasma-enhanced chemical vapor
deposition (PECVD) reactors for MEMS applications. Thick α-Si film up to 2 μm is widely used as a sacrificial layer in
the MEMS release process, however, the film quality and smoothness are limited by the cracking or peeling of thick film
due to their intrinsic stress. This achievement of as thick as 12 μm film was possible by tuning the deposition parameters
to a 'zero' value of the residual stress in the α-Si:H layer. The influence of the PECVD process parameters, such as
power, frequency mode, temperature, pressure and SiH4/Ar flow rates on tuning the residual stress and a good deposition
rate was analyzed. As a result, an almost "zero-stress" α-Si:H film and a deposition rate of 85nm/min was achieved for a
temperature of 200ºC, a pressure of 800 mTorr, a high-frequency power of 120W, with SiH4 flow rate of 120 sccm and
Ar flow rate of 500 sccm. The deposition of low-stress and thick (more than 12 μm in our case) α-Si:H layers was
possible without generation of peeling or hillock defects. Finally, the paper presents some MEMS applications of such a
deposited α-Si:H layer: a very good masking layer for dry and deep wet etching of glass; and a sacrificial layer for dry or
wet release of bridge/cavity structure.
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The SU8-based UV-LIGA process, which combines lithography with electroforming, is a low cost fabrication method
for producing MEMS and precision engineering parts. With lower surface energy and friction coefficient, these micro
parts are required for applications such as micro gears and movable microstructures. This paper introduces a technique to
fabricate Ni-PTFE micro parts using special treated galvanic bath. The experiment results show that the composite
electroforming process is robust and the fabricated Ni-PTFE parts have good tribological properties.
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A flexible tactile sensing module with NiCr strain gauges as sensing elements was fabricated by polymer MEMS
technology using polyimide materials where the one was the photo-definable polyimide precursor and the other was nonphoto-
definable. The unit sensor cell size of 32×32 tactile sensor array was 1mm × 1mm cell and its overall size was
5.5cm × 6.5cm. Especially, both the tactile sensor arrays and the pluggable terminals as flexible flat cable were
fabricated on the same polymer substrate easily to be connected the sensor array with a PCB board. The fabricated tactile
sensing module was measured continuously in the normal force range of 0~1N with tactile sensor evaluation system. The
value of resistance was relatively linear with normal force in the overall range of 0~1N. However, the variation of
resistance was decreased by more than 0.6N. The variation rate of resistance was 2.0%/N in the range of 0~0.6N and
1.5%/N in the range of 0.6~1N. Image display was identified corresponding by distribution of applied force. The
flexibility of the sensing module was adequate to be placed on any curved surface as a cylinder.
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Current technological challenges in materials science and high-tech device industry require the solution of boundary
value problems (BVPs) involving regions of various scales, e.g. multiple thin layers, fibre-reinforced composites, and
nano/micro pores. In most cases straightforward application of standard variational techniques to BVPs of practical
relevance necessarily leads to unsatisfactorily ill-conditioned analytical and/or numerical results. To remedy the
computational challenges associated with sub-sectional heterogeneities various sophisticated homogenization techniques
need to be employed. Homogenization refers to the systematic process of smoothing out the sub-structural
heterogeneities, leading to the determination of effective constitutive coefficients. Ordinarily, homogenization involves a
sophisticated averaging and asymptotic order analysis to obtain solutions. In the majority of the cases only zero-order
terms are constructed due to the complexity of the processes involved. In this paper we propose a constructive scheme
for obtaining homogenized solutions involving higher order terms, and thus, guaranteeing higher accuracy and greater
robustness of the numerical results. We present
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The modelling and simulation of periodic structures with defects define boundary value problems (BVPs) which
are conceptually and numerically difficult to solve. Innovative and problem-tailored analysis methods need to be
devised to solve defect problems efficiently and accurately. One possible attractive method is based on the ideas
related to the construction of Wannier functions. Wannier functions constitute a complete sequence of localised
orthogonal functions which are derived from associated periodic versions of defect problems. In this paper we
review general properties of Wannier functions from a linear algebra point of view, introduce an easy-to-use
symbolic notation for the diagonalisation of the governing equations and construct the Wannier functions for a
variety of phononic devices. Using certain distinguished properties inherent in the wavenumber-dependence of
the eigenvalues we prove the orthogonality and completeness of the Wannier functions in a conceptually novel
way.
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The rapid growth of the telecommunication and microelectronic industry has been pushing the performance limit
of the passive and active electronic components and devices alike. Thereby, improved performance of the devices
has become a necessity for operating frequencies moving into the MW region. Examples are Surface Acoustic
Wave (SAW) and Bulk AcousticWave (BAW) Devices which are miniaturized microelectronic devices with a wide
range of applications in signal processing, forming and sensing. Computation of electroacoustic field distribution
in these structures needs to be accurate, efficient and rigorous. However, the amount of data required for preand
post-processing is immensely large, and the processing and handling of data are extremely time consuming.
In this paper we propose a conceptually novel method for significantly reducing the computational time and
thus enhancing efficiency by pre-calculating relevant data, storing, and subsequently retrieving them whenever
they are required for device analysis and simulation. We propose a method for symbolically and conveniently
calculating two- or three dimensional integrals over the surface of an arbitrary triangle or within the volume of
an arbitrary tetrahedral. The results we have obtained are universal in that their application is not limited to
microacoustic devices.
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Paper reports the use of a new surfactant NCW-1002 as an addictive in TMAH wet anisotropic etching to improve the
etching characteristic on three silicon principle planes (i.e. (100), (110), (111) planes). Concentrations of TMAH from
2.5% to 10% with addition of various concentration of NCW-1002 are studied to find an optimal combination for a
improved smoothness and etch selectivity between (100) and (110) planes, which is necessary for the formation of
45°mirror plane (110) in (100) silicon surface. Etch rate and roughness of silicon planes were measured by Dektak II and
AFM respectively. Besides, this paper will explain the formation of 45°slope. By improving the selectivity or extending
the etching depth, we are able to enlarge the 45°portion on the mirror surface.
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In this study, the performance of two micro-thermoelectric coolers fabricated was investigated by theoretical calculation
and experimental testing of the samples. The natural convection rate and conduction rate were also considered. The
corrective implementation improved the theoretical calculation results.
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The development of MEMS devices differs substantially from product engineering methods used in more traditional
industries. The approach is characterized by a close customer involvement and product specific fabrication
processes. A large number interdependencies between device design on the one hand and manufacturing process
development on the other hand make product engineering in the MEMS area a rather tedious and complicated
task. In this paper we discuss a comprehensive customer-oriented MEMS product engineering methodology.
Both MEMS design and fabrication process development are analyzed with regard to procedures and interfaces
used in order to develop an appropriate CAD support either in terms of existing tools or by specifying individual
tools to be implemented. The manufacturing process development is part of this holistic approach and is
supported by a CAD environment for the management and the design of thin-film MEMS fabrication processes.
This environment has been developed by the authors and became recently commercially available.
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A method to create microfluidic devices by utilizing hot imprinting stamps formed using printed circuit boards is demonstrated. Very large microfluidic devices (15×15 cm2) can be created with lateral features down to 100 microns and depths of nominally 17-70 μm. Room temperature solvent bonding was found to be a simple method of sealing the channels. The work also decribes the fabriation and operation of thermally actuated microvalves with sub-second switching and micropumps based on the imprinting techniques described.
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In this paper, a novel analysis technique for the performance evaluation of micro-acoustic devices has been
proposed. Whereas traditional techniques typically focus solely on the frequency domain characteristics, we
employ a Joint Time-Frequency Analysis (JTFA), which has been shown to provide a more complete characterisation
of overall device performance and underlying physical phenomena. Although an emphasis is placed
on a Flexural Plate Wave (FPW) device, the analysis technique presented is applicable to a wider range of
micro-acoustic devices including Surface Acoustic Wave (SAW) structures and Thin-Film Bulk Acoustic Wave
Resonators (TFBARs).
SAWdevices, and indeed general filters, are typically described by a frequency domain characteristic, whereby
the entire time domain information is discarded. This type of analysis assumes that the device has reached quasistationary
conditions. By employing JTFA, the device performance can simultaneously be studied as a function
of both time and frequency. This type of analysis is typically useful where spurious acoustic modes are generated
which may influence the overall filter characteristic.
We have investigated the functional properties of various JTFA kernels, including those appearing in the
Wigner-Ville, Choi-Williams and Page distributions. A known deficiency associated with JTFA is the appearance
of a number of spurious cross-terms in the computations. Whereas the cross-terms are relatively simple to
detect for "monochromatic" (single-component) signals, it is not a trivial task to minimise such artifacts for
"polychromatic" (multi-component) signals, which are typical in micro-acoustic devices. We propose novel
methods for reducing the cross-terms interference appearing in JTFA, thereby improving the performance of the
analysis technique.
To investigate the application of the proposed technique, the simulated time domain response of a FPW
device was investigated. The Finite Element Method (FEM) package ANSYS 8.0 was utilised to obtain the
impulse response of the FPW structure under a dynamic transient analysis. A comparison is also made with the
spectral domain Green's function to verify the FEM solution, where excellent agreement is obtained. Based on
the FEM solutions, the insertion loss characteristics is calculated which represents a commonly applied frequency
domain method of analysing micro-acoustic devices. A comparison has been made between the insertion loss
characteristics and the proposed approach, where it is clearly demonstrated that the problem-adapted technique
provides significantly more detailed information.
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Transparency conversion mechanism and laser induced fast response velocity of bimetallic Bi/In thin film is studied.
Heat-treatment and laser exposure with different pulse width induced transparency is investigated by using
ultraviolet-visible (UV-VIS) spectrometer, X-ray diffraction (XRD), Auger Electron Scan (AES), microscope and field
emission scanning electron microscopy (FESEM). Research results show that oxidation is regarded as the reason for heat
treated and long-pulsed laser exposure induced transparency conversion. Laser ablation is demonstrated to be the main
reason for short-pulsed (~7ns) laser induced transparency conversion. For Bi/In thin film covered with a protection layer
of (ZnS)0.85(SiO2)0.15 thin film, it exhibit fast response as fast as less than 100ns. The conclusions contribute to
understanding and development of materials for thermal resist, photomask, optical storage medium and transparent
conductive oxide with better performance.
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In this paper we investigate the fabrication process of a novel polymer based pressure micro-sensor for use in
manometric measurements in medical diagnostics. Review and analysis of polymer materials properties and polymer
based sensors has been carried out and has been reported by us elsewhere [1]. The interest in developing a novel polymer
based flexible pressure micro-sensor was motivated by the numerous problems inherent in the currently available
manometric catheters used in the hospitals. The most critical issue regarding existing catheters was the running and
maintenance costs [2]. Thus expensive operation costs lead to reuse of the catheters, which increase the risk for disease
transmission. The novel flexible polymer based pressure micro-sensor was build using SU-8, which is a special kind of
negative photoresist. Single-walled carbon nanotubes (SWCNTs) and aluminum are used as the sensing material and
contacting electrodes respectively. The pressure sensor diaphragm was first patterned on top of an oxidized silicon wafer
using SU-8, followed by aluminum deposition to define the electrodes. The carbon nanotube is then deposited using
dielectrophoresis (DEP) process. Once the carbon nanotubes are aligned in between these electrodes, the remaining of
the sensor structure is formed using SU-8. Patterning of SU-8 and release from the substrate make the device ready for
further testing of sensing ability. This research not only investigates the use of polymeric materials to build pressure
sensors, but also explores the feasibility of full utilization of polymeric materials to replace conventional silicon
materials in micro-sensors fabrication for use in medical environments. The completed sensor is expected to form an
integral part of a large versatile sensing system. For example, the biocompatible artificial skin, is predicted to be capable
of sensing force, pressure, temperature, and humidity, and may be used in such applications as medical and robotic
system.
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Carbon Nano Tube (CNT) reinforced AZ91 metal matrix composites (MMC) were fabricated by the squeeze infiltrated
method. Properties of magnesium alloys have been improved by impurity reduction, surface treatment and alloy design,
and thus the usage for the magnesium alloys has been extended recently. However there still remain barriers for the
adaption of magnesium alloys for engineering materials. In this study, we report light-weight, high strength heat resistant
magnesium matrix composites. Microstructural study and tensile test were performed for the squeeze infiltrated
magnesium matrix composites. The wear properties were characterized and the possibility for the application to
automotive power train and engine parts was investigated. It was found that the squeeze infiltration technique is a proper
method to fabricate magnesium matrix composites reducing casting defects such as pores and matrix/reinforcement
interface separation etc. Improved tensile and mechanical properties were obtained with CNT reinforcing magnesium
alloys
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The purpose of this study is to systematically evaluate the performance of a portable chemical fume
extractor used for cleaning chemical fume in small work places. Four chemical liquids, a closed chamber,
and a metal-oxide sensor were used to evaluate its performance. The experimental results show that the
unit under test is able to extract high concentrations of the tested chemical vapors and the cleaning
processes take 5 minutes in average to clean out a strong-smelling fume concentration of 29 ppm. The
performance is evaluated in terms of the cleaning efficiency (η) and clean air delivery rate (CADR).
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The analysis of cellular activity when exposed to polydimethylsiloxane (PDMS) is necessary as this material
has been used in various applications such as tissue engineering and microfluidic devices for cellular studies
due to the polymer's unique mechanical properties. In this particular study, we investigated the effects of
corona surface treated PDMS with different cross-linker ratios on cellular activities by analyzing prostate
cancer cell (PC-3) and vascular smooth muscle cell (VSMC) adhesion and proliferation. Both cell lines were
subjected to a thin PDMS layer immediately after and 24 hours after corona treatment. The results indicated
steady cell adhesion and proliferation rates for both smooth muscle and prostate cancer cells when seeded
onto PDMS 24 hours after corona surface treatment, but significantly less cell adhesion when seeded
immediately after activation and controls (PDMS without any treatment). These results would allow future
PC-3 and VSMC experiments to be performed in a PDMS environment that is not detrimental for adhesion
and proliferation.
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Vu Anh Tuan, Bui Thi Hai Linh, Hoang Yen, Dinh Cao Thang, Tran Manh Cuong, Dang Tuyet Phuong, Tran Thi Kim Hoa, Hoang Vinh Thang, Nguyen Van Hoa, et al.
Proceedings Volume Micro- and Nanotechnology: Materials, Processes, Packaging, and Systems IV, 726915 (2008) https://doi.org/10.1117/12.810712
Nano TiO2 was synthesized by hydrothermal method. The sample was modified by doping transition metal ion (V, Cr
and Fe) and non metal (N). Doped TiO2 samples were characterized by XRD (X-ray diffraction), FE-SEM (Fieldemission
scanning electron microscopy) and UV-Vis (UV-Vis diffuse reflectance spectroscopy). Photocatalytic activity
in mineralization of xylene (vapor phase), methylene blue and active dyer PR (liquid phase) were tested. In comparison
to non-doped TiO2, V-,Cr-,Fe-doped TiO2 and N-doped TiO2 samples exhibited much higher photocatalytic activity
using visible light instead of UV.
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In this paper, we presented the fabrication process of miniature pH sensor arrays on flexible polymer
substrates. The repeatability of the sensors based on sol-gel fabrication processes was investigated. The
sensor repeatability was characterized with linearity, decay time, environmental parameter control and
potential stability. Similar linear responses were found in different batches of sensor arrays. Near super-
Nernstian responses were measured on each sensor with slope ranges from
-71.6 to -110 mV/pH within a
pH range between 2 and 12. The response times were compared in different batches. Six to twenty five
seconds of average decay time were shown in each sample repeatedly. Three sensors showed the close
potential response in different volumes of pH buffer solution. The sensor showed good stability in each
step of the titration process between pH values of 1.8 and 11.9. The peak and saturated potential values
presented high correlation with pH values with minor noises. The results showed good sensitivity,
stability and repeatability using the sol-gel processes for iridium-oxide pH sensors on flexible substrates.
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There are several ways to kill the bacterium and treat the wound by use of silver material. The silver material
also is a kind of sedative to keep people calm, especially for children. Because the bacterium resistance to the action of
drug, the medical application of silver material should be paid attention to.
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