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IEEE SENSORS

作者： Patrick C. Fletcher Y. Xu P. Gopinath J. Williams B. W. Alphenaar R. D. Bradshaw R. S. Keynton Departments of Mechanical Engineering University of Louisville Louisville KY USA Electrical and Computer Engineering University of Louisville Louisville KY USA ElectroOptics Research Institute and Nanotechnology Center University of Louisville Louisville KY USA Bioengineering University of Louisville Louisville KY USA

Our group has focused on the development of piezoresistive cantilevers for gas detection using a nonreaction-based method - viscous damping. This work represents a continuation of this effort by reporting on the development, fabrication and testing of a second generation device consisting of asymmetric piezoresistive cantilevers to maximize device sensitivity. The first mode of resonance, static & dynamic sensitivities, and Q-factors ranged from 40 kHz - 63 kHz, 1-6 Omega/mum & 3-17 Omega/mum, and 1700 - 4200, respectively, depending on piezoresistor geometry and beam length. The redesigned piezoresistive microcantilevers were 15 - 200 times more sensitive than the best symmetric design previously reported by our group.

关键词： Piezoresistance Leg Optical resonators Testing electrical resistance measurement Stress measurement Immune system Chemicals Computational geometry Damping

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A tactile feedback system for robotic surgery

A tactile feedback system for robotic surgery

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Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： Martin O. Culjat Chih-Hung King Miguel L. Franco Catherine E. Lewis James W. Bisley Erik P. Dutson Warren S. Grundfest UCLA Department of Surgery UCSB Department of Electrical and Computer Engineering UCLA Los Angeles CA USA UCLA Biomedical Engineering IDP CASIT Los Angeles CA USA UCLA Department of Surgery CASIT Los Angeles CA USA UCLA Departments of Neurobiology and Psychology CASIT Los Angeles CA USA UCLA Departments of Bioengineering Electrical Engineering and Surgery CASIT Los Angeles CA USA

A tactile feedback system was developed and mounted on the da Vinci robotic surgical system. The system features silicone-based tactile balloon actuators mounted on the robotic master controls, modified commercial piezoresistive sensors mounted on the robotic end effectors, and a pneumatic control system. The system has a frequency response of up to 20 Hz, a linear input force-output pressure relationship, and provides five discrete levels of actuation over a force input range of 0 to 25 N. A demonstration of the system with four subjects grasping a phantom with an embedded pressure-sensitive film suggested that less force was applied with tactile feedback. This paper describes the design, fabrication, characterization, and demonstration of the mounted tactile feedback system and its components. Ongoing studies using the system will assess the benefit of tactile stimuli to learning and control in robotic surgery.

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Fabrication of carbon nanotube-filled microchannels for biological separations

Fabrication of carbon nanotube-filled microchannels for biol...

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SEM Annual Conference and Exposition on Experimental and Applied Mechanics 2007

作者： Dorairaj, Rathissh Cambron, Scott D. Sumanasekera, Gamini Sumanasekera, Wasana Klinge, Carolyn M. Keynton, Robert S. Departments of Electrical and Computer Engineering University of Louisville Louisville KY Departments of Bioengineering University of Louisville Louisville KY Departments of Physics University of Louisville Louisville KY Departments of Biochemistry and Molecular Biology University of Louisville Louisville KY

ISBN: (纸本)1604232226

Gel electrophoresis, which consists of applying an electric field across a gel matrix filled with a conductive fluid medium, is a common method for separation, identification and analysis of macromolecules. Common problems associated with this widely used laboratory technique include reproducibility and repeatability. Specifically, variances in the ratio of the cross-linking agent to the amount of total monomers, environmental conditions during the polymerization process, Joule heating and human error lead to this lack of reproducibility and repeatability. Although human error cannot be totally eliminated, it can be minimized;additionally, the processing variables can be eliminated by developing an alternative sieving matrix material. Thus, the focus of this project is to develop a microfluidic platform filled with carbon nanotubes which will act as the sieving matrix for biological separations. The quartz-soda-lime glass-based device was fabricated using traditional micro/nanotechnology processes, including UV photolithography, buffered oxide etch (BOE), chemical vapor deposition (CVD) for the growth of carbon nanotubes (CNTs), and PDMS bonding. The carbon nanotube matrix was fabricated in a CVD furnace (700°C) using a 6-nm thin-film iron catalyst in the presence of ethylene. The microchannel substrate was bonded to a previously made PDMS sheet by oxygen plasma. It was determined that the thickness of the CNT membrane depended on the width-to-depth ratio of the microchannel. By the thermal CVD method, CNT membrane thicknesses of upto 44 μm were achieved.

关键词： Carbon nanotubes

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Electronic properties of organic-inorganic hybrid systems

Electronic properties of organic-inorganic hybrid systems

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46th State-of-the-Art Program on Compound Semiconductors (SOTAPOCS XLVI) and the 2nd International Symposium on Processes at the Semiconductor-Solution Interface - 211th ECS Meeting

作者： Li, Yang Sun, Ke Yang, Jianyong Dutta, Mitra Stroscio, Michael A. Departments of Electrical and Computer Engineering 851 S. Morgan Street MC 154 United States BioEngineering University of Illinois Chicago IL 60607 United States

ISBN: (纸本)9781566775519

Organic-inorganic hybrid structures enable integration of useful organic and inorganic characteristics within a single molecular scale. In addition to exhibiting useful properties, the hybrid materials can be fabricated into optoelectronic devices using simple and inexpensive fabrication techniques. Among the phenomena of importance in these systems are the mechanisms by which carrier transport occurs in such organic-inorganic hybrid structures. We have made hybrid nanostructures based on poly[2-methoxy-5-ethylhexyloxy-1,4- phenylenevinylene](MEH-PPV) and several various nanocrystalline quantum dots. Employing both optical and electronic techniques, we examine the charge transfer in different materials and study current through the structures. A minibands model is used to study the transmission of current. © The Electrochemical Society.

关键词： Optoelectronic devices

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Interactions of THz vibrational modes with charge carriers in DNA: Polaron-phonon interactions

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International Journal of High Speed Electronics and Systems 2007年第2期17卷 293-309页

作者： Ramadurai, Dinakar Yamanaka, Takayuki Li, Yang Vasudev, Milana Sankar, Viswanath Dutta, Mitra Stroscio, Michael A. Rajh, Tijana Saponjic, Zoran Bioengineering Department University of Illinois at Chicago 851 S. Morgan Street Chicago IL 60607 United States Electrical and Computer Engineering Department University of Illinois at Chicago 851 S. Morgan Street Chicago IL 60607 United States Physics Departments U. of Illinois at Chicago 851 S. Morgan St. Chicago IL 60607 United States Electrical and Computer Engineering BioEngineering and Physics Departments University of Illinois at Chicago 851 S. Morgan Street Chicago IL 60607 United States Chemistry Division Argonne National Laboratory Argonne IL 60439

This paper presents models and experimental measurements that shed light on THz-phonon mediated transport of polarons in biomolecules. Polaron transport in DNA has been considered recently in view of the expected derealization of charge carriers on a one-dimensional wire as well as the highly charged nature of DNA.1,2 An understanding of the electrical transport properties and THz-phonon interactions of biomolecules is important in view of DNA's potential applications both as electrically conductive wires and as structures that facilitate the chemically-directed assembly of massively integrated ensembles of nanoscale semiconducting elements into terascale integrated networks. Moreover, understanding these interactions provides information of the THz spectrum of vibrational modes in DNA. A primary focus of this paper is on charge transport in biomolecules using indirect-bandgap colloidal nanocrystals linked with biomolecules.3 Through a combination of theoretical and experimental approaches,4-7 this paper focuses on understanding the electrical properties and THz-frequency interactions of DNA. Moreover, this paper presents observed charge transport phenomena in DNA and discusses how these measurements are related to carrier scattering from the THz vibrational modes in DNA. Indeed, carrier transport in DNA is analyzed in light of theoretical calculations of the effects of THz-frequency phonon emission by propagating carriers, THz-frequency phonon absorption by propagating and trapped carriers, and effective mass calculations for specific sequences of the DNA bases.1-7 These studies focus on THz-phononmediated processes since an extra carrier on a one-dimensional chain minimizes its energy by forming an extended polaron, and since many biomolecules, including DNA, exhibit THz vibrational spectra.8 Accordingly, these calculations focus on THz-phonon-mediated processes. These results are discussed in terms of the role of THz-phonon-mediated charge trapping and detrapping

关键词： DNA

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Blinking mechanism of colloidal semiconductor quantum dots: Role of fluctuating double layer potential

Blinking mechanism of colloidal semiconductor quantum dots: ...

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46th State-of-the-Art Program on Compound Semiconductors (SOTAPOCS XLVI) and the 2nd International Symposium on Processes at the Semiconductor-Solution Interface - 211th ECS Meeting

作者： Dutta, Mitra Stroscio, Michael A. Liao, Sicheng Vasudev, Milana Yamanaka, Takayuki Departments of Electrical and Computer Engineering BioEngineering and Physics University of Illinois 851 S. Morgan Street MC 154 Chicago IL 60607 United States Departments of Electrical and BioEngineering University of Illinois 851 S. Morgan Street MC 154 Chicago IL 60607 United States Departments of Electrical and Physics University of Illinois 851 S. Morgan Street MC 154 Chicago IL 60607 United States

ISBN: (纸本)9781566775519

Colloidal semiconductor quantum dots are observed to blink with off- and on-times, τoff, and τon, respectively, that obey inverse power law distributions. In this paper, the role of the fluctuating double-layer potential in the blinking phenomenon is examined. As discussed, the existence of an energy barrier, E, that is a stochastic variable with an exponential distribution Pe(E) = (1/Eo)exp(-E/E o) in terms of the height of the energy variable, results in a distribution in the thermal activation time τ, pτ(τ), is described by an inverse power law. As discussed, in such cases, an Arrhenius process is characterized by a thermal activation time, τ, where τ = τOexp(E/kBτ) and E represents the energy barrier, T is the temperature, kB is Boltzmann's constant, and τO is a typical time. These principles are applied to the case of colloidal semiconductor quantum dots in electrolytic suspensions to analyze the role of the fluctuating double-layer potential in the blinking of colloidal semiconductor quantum dots. © The Electrochemical Society.

关键词： Semiconductor quantum dots

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High numerical aperture fall-field optical coherence tomography with space-invariant resolution without scanning the focus

High numerical aperture fall-field optical coherence tomogra...

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Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XI

作者： Marks, Daniel L. Ralston, Tyler S. Carney, P. Scott Boppart, Stephen A. Beckman Institute for Advanced Science and Technology Department of Electrical and Computer Engineering University of Illinois at Urbana-Champaign 405 N. Mathews Urbana IL 61801 Departments of Bioengineering and Medicine University of Illinois at Urbana-Champaign Urbana IL 61801

ISBN: (纸本)0819465429

In high-numerical-aperture optical coherence tomography, the depth-of-field is usually quite short and therefore the focus is scanned through the object to form a well-resolved image of the entire volume. However, this may be inconvenient for in vivo scanning when precision placement is not easily achieved between the object and the focusing objective. We show that by scanning the illumination wavelength, and using novel inverse scattering methods on the detected interferograms, features outside of the focus can be resolved and therefore the focus does not need to be scanned.

关键词： Optical tomography

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Optoelectronic properties for ZnO and related semiconductors in various nanoscale geometries

Optoelectronic properties for ZnO and related semiconductors...

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46th State-of-the-Art Program on Compound Semiconductors (SOTAPOCS XLVI) and the 2nd International Symposium on Processes at the Semiconductor-Solution Interface - 211th ECS Meeting

作者： Yang, J. Yamanaka, T. Sun, K. Stroscioa, M.A. Dutta, M. Zhong, J. Chen, H. Saraf, G. Lu, Y. Department of Electrical and Computer Engineering University of Illinois at Chicago Chicago IL 60607 United States Department of Bioengineering University of Illinois at Chicago Chicago IL 60607 United States Department of Physics University of Illinois at Chicago Chicago IL 60607 United States Departments of Electrical and Computer Engineering Rutgers the State University of New Jersey Piscataway NJ 08854 United States

ISBN: (纸本)9781566775519

Zinc oxide, ZnO, is a direct wide bandgap semiconductor, with a large exciton binding energy (60 meV). Many of its properties promise great potential for many optoelectronic device applications. In order to explore the nanoscale device applications and gain more understanding of the ZnO material, our research has focused on the optical characterization of several ZnO samples including both films and nanorods (nanotips) grown on different substrates. We will present experimental results of photoluminescence (PL) as a function of temperature and Raman scattering data at room temperature (RT). The spontaneous polarization in ZnO and GaN will be modeled and compared for these two similar wurtzite wide band gap materials. Finally, we will present the calculations of the electron and hole transmission mini bands in a three dimensional matrix of colloidal ZnO quantum dots and conductive polymers also a promising material in optoelectronic device applications. ©The Electrochemical Society.

关键词： Zinc oxide

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Integrated DNA-nanoparticle complexes: Synthesis, electrical and optical properties

Integrated DNA-nanoparticle complexes: Synthesis, electrical...

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New Bioanalytical and Biomedical Methods - 211th ECS Meeting

作者： Vasudev, Milana Yamanaka, Takayuki Yang, Jianyong Li, Yang Stroscio, Michael A. Dutta, Mitra Departments of BioEngineering MC 154 University of Illinois 851 S. Morgan Street Chicago IL 60607 United States Departments of Electrical and Computer Engineering MC 154 University of Illinois 851 S. Morgan Street Chicago IL 60607 United States Departments of Physics MC 154 University of Illinois 851 S. Morgan Street Chicago IL 60607 United States

ISBN: (纸本)9781605601717

We have studied the optoelectronic properties of nanostructure-DNA complexes chemically assembled on transparent, semi-rigid substrates such as poly-methyl methacrylate (PMMA) (1,2). DNA can be immobilized on these substrates by chemically modifying the PMMA substrates and using suitable cross-linking agents. Additionally, DNA strands end-terminated with TiC 2 nanoparticles are used in this study to observe DNA cleavage through photoinduced charge carriers from the TiO2 trapped in guanine (G-) rich sites;polaron transport in such a DNA molecule is analyzed theoretically (3) to provide an understanding of charge injection into DNA as well as the formation, transport of polarons in DNA. Subsequent AFM measurements are used to study the structural characteristics of DNA on the PMMA substrates. Raman spectral lines observed in the 750-850 cm-1 region may be attributed to the phosphodiester backbone in the DNA. The fabrication of these nanostructure-DNA ensembles will be discussed and their Raman and AFM characterization will be presented. © The Electrochemical Society.

关键词： DNA

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A Video Processing Approach to the Study of Obesity

A Video Processing Approach to the Study of Obesity

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IEEE International Conference on Multimedia and Expo (ICME)

作者： Ning Yao R. J. Sclabassi Qiang Liu Jie Yang John D. Fernstrom Madelyn H. Fernstrom Mingui Sun Department of Neurosurgery University of Pittsburgh USA University of Pittsburgh Pittsburgh PA US Department of Electrical & Computer Engineering University of Pittsburgh USA School of Computer Science Carnegie Mellon University USA Departments of Psychiatry Pharmacology University of Pittsburgh Departments of Psychiatry Surgery Epidemiology University of Pittsburgh Departments of Electrical & Computer Engineering Neurosurgery Bioengineering University of Pittsburgh

Currently, a significant obstacle in identifying the most important factors that contribute to obesity is the lack of appropriate tools to evaluate food consumption and physical activity on a daily basis. This paper presents a novel video-based approach to estimating the energy intake and expenditure of individuals who are over-weight or obese. We propose to utilize a miniature video camera to chronically record data surrounding an individual's daily activity. From the recorded data, energy intake and expenditure are extracted objectively using signal processing algorithms. We discuss two algorithms which are both featured with low computational complexity, suitable for processing large sets of field-acquired video data. These algorithms estimate: (i) energy intake (caloric content) by determining the physical dimensions of the foods consumed; and (ii) energy expenditure by evaluating the extent of the subject's physical activity. We also report initial experimental results to demonstrate the effectiveness of the new approach.

关键词： Food technology Cameras Signal processing algorithms Cardiac disease Bone diseases Cardiovascular diseases Motion measurement Video recording Legged locomotion Sun

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