Two-Port Stacked Piezoelectric Aluminum Nitride Contour-Mode Resonant MEMS

This paper reports on design, fabrication and experimental testing of a new class of two-port stacked piezoelectric aluminum nitride contour-mode micromechanical resonators that can be used for RF filtering and timing applications. This novel design consists of two layers of thin film AlN stacked on top of each other and excited in contour mode shapes using the d31 piezoelectric coefficient. Main feature of this design is the ability to reduce capacitive parasitic feedthrough between input and output signals while maintaining strong electromechanical coupling. For example, these piezoelectric contour-mode resonators show a quality factor of 1,700 in air and a motional resistances as low as 175 Ω at a frequency of 82.8 MHz. The input to output capacitance has been limited to values below 80 fF, therefore simplifying signal detection even at high frequencies

Single-Chip Multiple-Frequency ALN MEMS Filters Based on Contour-Mode Piezoelectric Resonators

This paper reports experimental results on a new class of single-chip multiple-frequency (up to 236 MHz) filters that are based on low motional resistance contour-mode aluminum nitride piezoelectric micromechanical resonators. Rectangular plates and rings are made out of an aluminum nitride layer sandwiched between a bottom platinum electrode and a top aluminum electrode. For the first time, these devices have been electrically cascaded to yield high performance, low insertion loss (as low as 4 dB at 93MHz), and large rejection (27 dB at 236 MHz) micromechanical bandpass filters. This novel technology could revolutionize wireless communication systems by allowing cofabrication of multiple frequency filters on the same chip, potentially reducing form factors and manufacturing costs. In addition, these filters require terminations (1 kOmega termination is used at 236 MHz) that can be realized with on-chip inductors and capacitors, enabling their direct interface with standard 50-Omega systems

Piezoelectric Aluminum Nitride Vibrating Contour-Mode MEMS Resonators

This paper reports theoretical analysis and experimental results on a new class of rectangular plate and ring-shaped contour-mode piezoelectric aluminum nitride radio-frequency microelectromechanical systems resonators that span a frequency range from 19 to 656 MHz showing high-quality factors in air (Qmax = 4300 at 229.9 MHz), low motional resistance (ranging from 50 to 700 Ω), and center frequencies that are lithographically defined. These resonators achieve the lowest value of motional resistance ever reported for contour-mode resonators and combine it with high Q factors, therefore enabling the fabrication of arrays of high-performance microresonators with different frequencies on a single chip. Uncompensated temperature coefficients of frequency of approximately 25 ppm/°C were also recorded for these resonators. Initial discussions on mass loading mechanisms induced by metal electrodes and energy loss phenomenon are provided

Gel-seq: A Method for Simultaneous Sequencing Library Preparation of DNA and RNA Using Hydrogel Matrices

The ability to amplify and sequence either DNA or RNA from small starting samples has only been achieved in the last five years. Unfortunately, the standard protocols for generating genomic or transcriptomic libraries are incompatible and researchers must choose whether to sequence DNA or RNA for a particular sample. Gel-seq solves this problem by enabling researchers to simultaneously prepare libraries for both DNA and RNA starting with 100 - 1000 cells using a simple hydrogel device. This paper presents a detailed approach for the fabrication of the device as well as the biological protocol to generate paired libraries. We designed Gel-seq so that it could be easily implemented by other researchers; many genetics labs already have the necessary equipment to reproduce the Gel-seq device fabrication. Our protocol employs commonly-used kits for both whole-transcript amplification (WTA) and library preparation, which are also likely to be familiar to researchers already versed in generating genomic and transcriptomic libraries. Our approach allows researchers to bring to bear the power of both DNA and RNA sequencing on a single sample without splitting and with negligible added cost

IMECE2003-41313 DYNAMIC MODELING OF A THERMALLY-DRIVEN MICRO DIFFUSER PUMP

ABSTRACT In this study, we present the dynamic modeling of a micro diffuser pump by employing the commercial software package CFDRC. Two types of time-dependent pressure boundary conditions are applied to the inlet. Sinusoidal and square wave functions with various amplitudes and frequencies are used. The results indicate a rectification effect such that a net flow in the divergent direction of the diffuser is gained over the time. In addition, the model is able to show the correlation of flow rate with frequency by flow circulation effects. This impact of the transient flow on the pumping performance is discussed. The modeling results are also compared to experimental data found in the literature. The net flow rates predicted by the 3D modeling are found to have good agreement at low excitation frequencies. To evaluate the validity of the imposed pressure boundary condition, the heat transfer model of the evaporation process is used

Gel-seq: Whole-Genome and Transcriptome Sequencing by Simultaneous Low-Input DNA and RNA Library Preparation Using Semi-Permeable Hydrogel Barriers

The advent of next generation sequencing has fundamentally changed genomics research. Unfortunately, standard protocols for sequencing the genome and the transcriptome are incompatible. This forces researchers to choose between examining either the DNA or the RNA for a particular sample. Here we describe a new device and method, collectively dubbed Gel-seq, that enables researchers to simultaneously sequence both DNA and RNA from the same sample. This technology makes it possible to directly examine the ways that changes in the genome impact the transcriptome in as few as 100 cells. The heart of the Gel-seq protocol is the physical separation of DNA from RNA. This separation is achieved electrophoretically using a newly designed device that contains several different polyacrylamide membranes. Here we report on the development and validation of this device. We present both the manufacturing protocol for the device and the biological protocol for preparing genetic libraries. Using cell lines with uniform expression (PC3 and Hela), we show that the libraries generated with Gel-seq are similar to those developed using standard methods for either RNA or DNA. Furthermore, we demonstrate the power of Gel-seq by generating a matched genome and transcriptome library from a sample of 100 cells collected from a mouse liver tumor

Monitoring of the central blood pressure waveform via a conformal ultrasonic device.

Continuous monitoring of the central-blood-pressure waveform from deeply embedded vessels, such as the carotid artery and jugular vein, has clinical value for the prediction of all-cause cardiovascular mortality. However, existing non-invasive approaches, including photoplethysmography and tonometry, only enable access to the superficial peripheral vasculature. Although current ultrasonic technologies allow non-invasive deep-tissue observation, unstable coupling with the tissue surface resulting from the bulkiness and rigidity of conventional ultrasound probes introduces usability constraints. Here, we describe the design and operation of an ultrasonic device that is conformal to the skin and capable of capturing blood-pressure waveforms at deeply embedded arterial and venous sites. The wearable device is ultrathin (240 μm) and stretchable (with strains up to 60%), and enables the non-invasive, continuous and accurate monitoring of cardiovascular events from multiple body locations, which should facilitate its use in a variety of clinical environments

NANOSCALE JOULE HEATING ALONG SILICON NANOWIRE AND ITS NANOSCALE HEATER APPLICATION

ABSTRACT In this paper, we present numerical and experimental studies on the nanoscale Joule heating along the single crystalline silicon nanowires. 50-100nm wide single crystalline silicon nanowires are heated via Joule heating by applying an electrical potential across them. Numerical simulation result predicts an extremely localized temperature field by resistive heating of silicon nanowire. We experimentally verified this highly localized heating of silicon nanowires by AFM imaging of localized thermal ablation of polytetrafluoroethylene (PTFE) thin film. This result implies potential applications of silicon nanowires as nanoscale heaters for the generation of highly localized temperature fields INTRODUCTION Nanowires are wires with diameters in the nanometer range and high aspect ratio (length/width). Their lateral dimensions are usually constrained to 1 to a few 100's nm while the longitudinal dimensions are unconstrained. Because of their dimensions, they exhibit distinct electronic properties (eg. quantum confinement [1]), thermal properties (decreased thermal conductivity by boundary scattering [2]), etc. compared to the bulk materials. Due to these interesting properties, they are drawing a great attention in various fields including nanoscale electronic