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MEMS, NANO and Smart Systems, 2003. Proceedings. International Conference on

Date 20-23 July 2003

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Displaying Results 1 - 25 of 82
  • On the role of machine learning algorithms in developing MEMS components

    Page(s): 108 - 113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (226 KB) |  | HTML iconHTML  

    This paper provides a review of several significant applications of machine learning tools in the development of MEMS components and devices. Four topics are covered, two represent traditional applications of artificial neural networks, drag reduction and reliability forecasting, and two are non-traditional applications, namely model reduction and MEMS based neurocomputing. View full abstract»

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  • Transition of MEMS technology to nanofabrication

    Page(s): 118 - 122
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    The transition of MEMS technology to nano fabrication is a solution to the growing demand for smaller and high-density feature sizes in the nanometer scale. Techniques for fabricating μm-, and nm-features will be discussed, and results achieved with nanoimprinting technologies will be presented. View full abstract»

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  • RF MEMS devices

    Page(s): 103 - 107
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (978 KB) |  | HTML iconHTML  

    This paper addresses the use of RF MEMS devices in wireless and satellite communication systems. Novel configurations are presented for MEMS variable capacitors, MEMS tunable inductors and RF MEMS multiport switches. The tuning range of the variable capacitor was measured and found to be 280%, which far exceeds that of the traditional parallel plate MEMS variable capacitors. The MEMS tunable inductor is realized using MEMS fixed inductors, capacitors and a variable MEMS capacitor. The proposed MEMS multiport switch has demonstrated a superior RF performance up to 20 GHz. View full abstract»

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  • Spintronics, and electrical spin injection in a two dimensional electron gas

    Page(s): 234 - 239
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (235 KB) |  | HTML iconHTML  

    The manipulation of electron spin offers new dimensions for basic and applied research, and the potential for new capabilities for electronics technology. Interest in digital electronics applications has spread to a variety of information systems and generated need for new devices, such as a Spintronic device with power gain. This motivates transport studies of spin polarized electrons in a high mobility two dimensional electron gas (2DEG). Recent experiments have used an FET-like geometry with ferromagnetic metal source and drain, as spin injector and detector, on an InAs single quantum well (SQW) channel, and a measurement of the spin dependent electron mean free path in the SQW has been made. An overview of Spintronics, including discussions of integrated applications in memory, reprogrammable logic, system-on-a-chip, and biotechnology, provides a broader context for this work. View full abstract»

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  • A new class of tunable RF MEMS inductors

    Page(s): 114 - 115
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    In this paper, we present results from our research on tunable inductors. The tunability is achieved with the use of thermal actuators that control spacing between main and secondary inductor. View full abstract»

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  • High-temperature Bragg grating waveguide sensor

    Page(s): 400 - 404
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (329 KB) |  | HTML iconHTML  

    Design and analyses of a periodic dielectric Bragg grating waveguide temperatures reported in this work. The sensor is capable to measure temperatures ranging from room temperature to over 1200°C. By using this sensor combined with a wavelength shifting detector and radiation detection schemes, a wide range thermometer can be built. Temperature can be measured in two steps using our thermal sensor. First step is to detect the wavelength shifting by an optical spectrum analyzer (OSA). The wavelength shifting could be converted to the change of environment temperature. This method is appropriate for the temperatures ranging from 20°C to 600°C. Another step is to detect the power of the probe radiation for the temperature range of over 600°C to the melting point of the probes. This sensor has potential applications in many areas particularly in aerospace industries. View full abstract»

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  • RF MEMS switch for wireless LAN applications

    Page(s): 100 - 102
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (294 KB) |  | HTML iconHTML  

    Double cantilever beam MEMS switch was developed for wireless LAN applications. The two beams are controlled by a single actuation electrode. The dimension of the fabricated cantilever beam is 150 μm × 60 μm × 0.6 μm. The spacing between the top beam and the bottom ground electrode was approximately 1 μm. This switch has low pull-in voltage of 15 V and fast switching speed of 60 μs. An RF performance with >-50 dB isolation below 5 GHz and <-0.18 dB up to 30 GHz was observed. View full abstract»

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  • Success factors in commercializing university MEMS technology through the WTC's microfabrication laboratory

    Page(s): 123 - 127
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB) |  | HTML iconHTML  

    The Washington Technology Center, a state-chartered science and technology organization, headquartered at the University of Washington in Seattle, began its MEMS Initiative in 1997 to build core capabilities at the state's universities and to foster commercialization of university-developed MEMS technology. Key to the success of the Initiative was establishment of the WTC's Microfabrication Laboratory a 15,000 sq. ft. user-supported cleanroom facility for academic and industrial MEMS research, development, prototype product manufacturing and foundry processing. Since that time, the Microfab Lab has grown to become the premier MEMS fabrication facility in the Pacific Northwest, with 180 users from 40 academic research groups and 30 private companies, and annual revenues approaching $1 M. This paper will cover the key success factors and lessons learned in commercializing micro-technology through start-up companies and industry-university partnerships over the past 6 years. The evolution of the Microfabrication Lab, in particular, will be described to illustrate how technical capabilities, laboratory management and business planning were adapted to attract and meet the needs of a growing user base. View full abstract»

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  • A proposal for the multivalued modulation system based on the projection to subspace

    Page(s): 383 - 387
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    A communication system using the sequence that the orthogonal basis in m-dimensional space is formed by projecting, in the n-dimensional space, is proposed. As a symbol for conventional communication, it seems to be advantageous in terms cf results to orthogonalize, especially, in relation to the error rate. But, it is possible to reduce the error rate using the communication system in this report by using a symbol which is not specially orthogonalized. In this report, the communication system is described, and it is evaluated on the performance from the perspective of error rate and communication speed. View full abstract»

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  • Finite element modeling of a capacitive micromachined ultrasonic transducer

    Page(s): 405 - 410
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (297 KB) |  | HTML iconHTML  

    Capacitive micromachined ultrasonic transducers have been investigated using finite element analysis. Three ANSYS models have been developed to illustrate the collapse voltage and operating frequency of CMUTs. A 2D axisymmetric model is used to illustrate the relationship between collapse voltage and electrode radius. The model agrees with past results for electrode radius sizes between full membrane radius and half membrane radius. A 3D solid model is utilized to demonstrate the resonant frequency of the CMUT silicon nitride membrane. A reduced order model is also used to depict the resonant frequency. Both models demonstrate a resonant operating frequency around 2.3 MHz for a membrane with a radius of 50 microns, a thickness of 1 micron, a residual stress of 60 MPa (tension) and biased at 30 VDC. The results are validated using previously reported findings. View full abstract»

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  • Quantum size effect in magnetic tunnel junctions with single-crystal ultrathin electrodes

    Page(s): 316 - 320
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (357 KB) |  | HTML iconHTML  

    Control of coherent electron transports in spintronic devices is an essential issue to realize highly functional spin-devices such as spin-dependent resonant-tunneling transistors. The spin dependent resonant tunneling via the quantum-well states in the electrode gives us many clues to understand and to control transport property in magnetic tunnel junctions (MTJs). To observe the quantum-well oscillations in TMR effect, we prepared the magnetic tunnel junctions with single-crystal ultrathin electrode or insertion layers. The MTJs with an ultrathin Fe [001] electrode shows the oscillation of TMR ratio as a function of the biasing voltage. In the case of an ultrathin Cu [001] layer inserted between a Co electrode and Al2O3 barrier layer, we found large oscillations of TMR with respect to the thickness of the Cu electrode. These results clearly show a feasibility of the coherent spintronic devices using metallic systems. View full abstract»

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  • Smart materials: applications of nanotechnology in drug delivery and drug targeting

    Page(s): 82 - 83
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (198 KB) |  | HTML iconHTML  

    This presentation will give an overview of the current use of nanoparticles as drug carriers and will discuss their future use in drug targeting and drug delivery of active molecules. Today's progress in cell biology and biotechnology enables scientists to synthesize highly active molecules to target specific intra-cellular receptors. The clinical use of such molecules is often very limited because of their peptide or oligonucleotide nature. They are highly active in vitro in isolated cell systems, but a short half-life or limited cell uptake in vivo prevent their clinical use. To overcome the limitations in cellular uptake of highly active molecules, the use of nano-sized carriers is the focus of modern drug delivery strategies. The utilization of such particles as drug targeting vectors is an emerging field of pharmaceutical sciences. View full abstract»

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  • Benzocyclobutene (BCB) based intracortical neural implant

    Page(s): 418 - 422
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (398 KB) |  | HTML iconHTML  

    A novel structure for chronically implantable cortical electrodes using new Benzocyclobutene (BCB) bio-polymer was devised, which provides both flexibility for micro-motion compliance between brain tissues and skull and stiffness for better surgical handling. BCB is very attractive polymer for stable long-term implant function, because it has flexibility, biocompatibility, low moisture uptake (<0.2 wt%), and low dielectric constant (∼2.6). For easy operation during surgical insertion, a 5∼10μm thick silicon backbone layer is attached to the desired region of the electrode to increase the stiffness. It is then followed by 1 mm of flexible part of the electrode without silicon backbone layer designed to absorb stress from any micro-motion between the brain tissue and the electrode. The fabricated implants have tri-shanks with 5 recording sites (20x20μm) and 2 vias (40x40μm) on each shank. BCB electrodes with 5μm and 10μm thick backbone silicon penetrated pia of rat brain without buckling. View full abstract»

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  • Polymeric nanoparticles for targeted delivery of therapeutic vaccines to dendritic cells

    Page(s): 242 - 246
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1536 KB) |  | HTML iconHTML  

    Dendritic cells (DCs) are the sentries of the immune system. They detect pathogens entering the body and activate immune responses against them through multiple nanoscopic molecular interactions. Pathogen-mimicking nanoparticles capable of such interactions were fabricated by incorporating monophosphoryl lipid A in a biodegradable polymer, poly(D,L-lactic-co-glycolic acid) (PLGA). The uptake of PLGA nanoparticles by human and mouse DCs was conclusively demonstrated by confocal laser scanning microscopy. Delivery of antigens in PLGA nanoparticles was shown to be more efficient than their delivery in soluble form for activation of T cell responses against a variety of antigens including a MUCI peptide (BLP25) cancer vaccine. A PLGA nanoparticulate formulation of BLP25 induced potent T cell responses and anticancer effects in a mouse lung cancer model. These results indicate that PLGA nanoparticles mimicking certain features of pathogens are efficient delivery systems for targeting therapeutic vaccines to DCs and activation of potent T cell responses. View full abstract»

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  • Finite element simulation and theoretical analysis of microelectromechanical system relays

    Page(s): 292 - 296
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    This paper studies the static and dynamic behaviors of a novel microrelay applied in microelectromechanical systems (MEMS) by electromagnetic attraction. The device is composed of a square planar coil, a movable magnetic film with two-supporting cantilever beams and a pair of contacts. The electromagnetic force yielded by the exciting electromagnetic coil actuates the microrelay, and the main advantage is its capability of providing higher forces over relatively large distance. Static and dynamic finite element (FE) simulations are implemented to obtain the mechanical characteristics of the microrelay, the natural frequencies and mode shapes under different levels of electromagnetic attraction. Theoretical studies on the dynamic model are developed to validate the FE simulation results. Good agreement is found between the FE simulation and the theoretical analysis. View full abstract»

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  • Micromachined needles for microbiological sample and drug delivery system

    Page(s): 247 - 250
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (929 KB) |  | HTML iconHTML  

    In this paper, the research and development of micromachined needles for microbiological sample and drug delivery system are reviewed. The micromachined needles can be classified into in-plane and out-of-plane needles. The features of those microneedles are analyzed and discussed. In addition, the design criteria of micromachined needles are proposed. At the same time, the further research of micromachined needles is also discussed. Based on those analysis, a new microneedle structure has been proposed. View full abstract»

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  • Electrostatic deflections of volume constrained MEMS

    Page(s): 76 - 80
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (300 KB) |  | HTML iconHTML  

    Electrostatic forces play a central role in micro- and nanoelectromechanical systems (MEMS and NEMS) and are integral to the rapidly developing field of microfluidics. In electrostatic-elastic systems the interaction of elastic membranes with static electric fields causes membrane deflection. In microfluidic systems, the interaction of static electric fields with small quantities of fluid leads to droplet motion and breakup. In numerous situations of practical interest, the system may be viewed as an elastic membrane enclosing a finite fixed volume. This volume constraint leads to a modification of the standard equations governing electrostatic-elastic interactions. In this paper the basic equations for an idealized volume constrained system are presented and modifications to the un-constrained solution set discussed. View full abstract»

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  • Evaporated nanostructured Y2O3:Eu thin films

    Page(s): 327 - 331
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1169 KB) |  | HTML iconHTML  

    Europium-doped yttrium oxide (Y2O3:Eu) is a well-known luminescent material that has been experimented with in recent years in thin film form. However, to date there has not been a great effort put into altering the nanostructure of these films. A thin film deposition technique called glancing angle deposition (GLAD) allows for a high degree of control over the nanostructure of the thin film, resulting in thin films with nanostructures ranging from chevrons and posts to helices. GLAD was used here to make europium-doped yttrium oxide thin films with different nanostructures. Scanning electron microscopy was then used to characterize the nanostructures of the films, while UV excitation was used to characterize the photoluminescence properties of the films. View full abstract»

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  • Development of a humidity microsensor with thermal reset

    Page(s): 89 - 93
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB) |  | HTML iconHTML  

    The present project is aimed at developing a capacitive humidity microsensor to measure humidity profiles inside the human respiratory tract. The ultimate goal of the project is to design the sensor with minimum size and with maximum sensitivity providing minimum response time. The sensor will allow determination of humidity variation in different generations of the human lung during a breath. The design process involves an appropriate simulation of the sensor to investigate the influence of several parameters on its sensitivity, and to develop a microheater that would be used to thermally reset the sensor. This sensor consists of interdigitated electrodes formed as a capacitor using aluminum as conductor and polyimide as dielectric built on a silicon substrate. For the thermal resetting, a polysilicon microheater will be built just underneath the sensor. The system should have quick absorption of moisture and ideally have a response time of less than 1 s. This specific requirement would allow for several measurements during one breath period. In order to meet these constraints a capacitive sensor was designed with a dielectric sensitive to humidity. Other parameters such as shapes of air contact surfaces, domain dimensions, properties of materials, etc. are analyzed and results are shown as well. View full abstract»

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  • Relaxor properties of TlInS2 composites with nanodomain state

    Page(s): 159 - 162
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    Recent theoretical investigations predict that the thermal filling of trap centers could lead to an intricate sequence of phase transitions with unstable boundary state between the phases. This fact has motivated the experimental study of ferroelectric phase transitions in TlInS2 composites where the cationic impurities can form the capture levels (traps) at the bottom of the conduction band. In this paper the results of experimental investigation of dielectric, polarization and pyroelectric properties of TlInS2 composites are presented. It was shown that TlInS2 composites display all peculiarities that are typical for relaxor ferroelectrics. View full abstract»

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  • First results in patterning of ultra high aspect ratio microstructures by a 4T wave length shifter at BESSY

    Page(s): 177 - 180
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1416 KB) |  | HTML iconHTML  

    Both X-ray lithography beamlines at BESSY can be operated in three different modes: one coming from a dipole (1.3 T) is used for standard exposures for patterning PMMA and SU-8, while the other beamline, coming from a straight section of the storage ring, can be operated in soft wavelength mode (0.4 T) or alternatively in wave length shifter mode (4T). Using the soft wave length mode, copying processes for X-ray mask can be carried, while the very hard radiation generated in the wave length shifter (WLS) modes best for patterning ultra thick PMMA layers up to several mm in thickness. In WLS mode the higher magnetic field of 4T is shifting the critical photon energy to 7.7 keV compared to a standard dipole magnet with 2.5 keV. The lateral intensity homogeneity of this beamline is very high. Tests for using the WLS mode for ultra deep X-ray lithography (UDXRL) were performed and delivered very good results. PMMA layers of up to 4 mm in thickness were patterned successfully. Similar patterning methods to fabricate high aspect ratio micro parts were reported in literature. View full abstract»

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  • Terahertz wave propagation in multiwall carbon nanotubes

    Page(s): 430 - 434
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (242 KB) |  | HTML iconHTML  

    This paper aims to study sound wave propagation in individual multiwall carbon nanotubes based on a multiple-elastic beam model. The present model predicts that there exist (N-1) critical frequencies (within terahertz range) for an N-wall carbon nanotube. Sound wave propagation in multiwall carbon nanotubes is almost coaxial only when the frequency is much below all critical frequencies, and becomes substantially non-coaxial when the frequency is higher than at least one of the (N-1) critical frequencies. In the latter case, the sound speeds predicted by the present model are significantly higher or lower than that given by the existing single-beam model. Hence, terahertz sound waves in multiwall carbon nanotubes exhibit complex new phenomena and are essentially non-coaxial. View full abstract»

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  • Finite-element modeling of shape memory alloy components in smart structures, part II: Application on shape-memory-alloy-embedded smart composite for self-damage control

    Page(s): 423 - 429
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (335 KB) |  | HTML iconHTML  

    For pt.I, see ibid., no.3, p.015-021 (2003). The finite element procedure proposed in part I was successfully used to model a smart-self-damage control system consisted of SMA wires embedded in a polymeric matrix. A parametric study was performed to investigate the effect of various parameters on the performance of the system. It was found that increasing current density speeds up the recovery process although it adds more heat to the system. Also, it was found that increasing wire diameters although speeds up the recovery process as well, it might cause harmful effects to the system by increasing the difference in CTE forces effect. Increasing number of activated wires was found to be beneficial as it reduces the amount of phase transformation and forces required per wire, and increases system sensitivity to small cracks. It is suggested that convection coefficient not to be too low or to high, and the initial temperature of the system to be as close to the Austenite start temperature as possible. It was also found that SMA wires prestraining have negligible effects if its not too low. View full abstract»

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  • Molecular dynamics calculations of the electrostatic properties of tubulin and their consequences for microtubules

    Page(s): 56 - 61
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    We present the results of molecular dynamics computations based on the atomic resolution structures of tubulin published as 1TUB and 1 JFF in the Protein Data Bank. Values of net charge, spatial charge distribution and Cartesian dipole moment components are obtained for the tubulin alpha-beta heterodimer. Physical consequences of these results and subsequent computations are discussed for microtubules in terms of the effects on test charges, test dipoles, and neighboring microtubules. Our calculations indicate typical distances over which electrostatic effects can be felt by biomolecules, ions, and other microtubules. We also demonstrate the importance of electrostatics in the formation of the microtubule lattice and the tubulin-kinesin binding strength. View full abstract»

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  • Lattice gas automata simulation of atomistic surface growth

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    "Summary form only given". Here we describe a method based on lattice gas automata to numerically simulate atomistic surface growth processes during thin film deposition. Using a realistic approximation of surface energetics, we are able to scale our simulation time to real deposition time corresponding to individual atomic diffusion jumps. The method allows us to model adatom-adatom interaction explicitly, an important feature for investigating the effects of surface elastic forces on surface morphology. The real deposition time and the adatom-adatom interaction distinguishes our method from the more standard kinetic Monte-Carlo simulations of atomistic surface growth. Results obtained for Si/Si(001) deposition for both flat and stepped substrates will be presented. View full abstract»

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