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Sample records for suspended gate field

  1. Suspended graphene devices with local gate control on an insulating substrate.

    Science.gov (United States)

    Ong, Florian R; Cui, Zheng; Yurtalan, Muhammet A; Vojvodin, Cameron; Papaj, Michał; Orgiazzi, Jean-Luc F X; Deng, Chunqing; Bal, Mustafa; Lupascu, Adrian

    2015-10-09

    We present a fabrication process for graphene-based devices where a graphene monolayer is suspended above a local metallic gate placed in a trench. As an example we detail the fabrication steps of a graphene field-effect transistor. The devices are built on a bare high-resistivity silicon substrate. At temperatures of 77 K and below, we observe the field-effect modulation of the graphene resistivity by a voltage applied to the gate. This fabrication approach enables new experiments involving graphene-based superconducting qubits and nano-electromechanical resonators. The method is applicable to other two-dimensional materials.

  2. Sedimentation of suspended solids in ultrasound field

    Directory of Open Access Journals (Sweden)

    Vikulina Vera

    2018-01-01

    Full Text Available Physical and chemical effects of aquatic environment that occur in an ultrasonic field change the sedimentation rate of coagulated suspension. This might only happen in case of cavitation of ultrasonic filed that causes a change of potentials of the medium. Research of the influence of ultrasonic vibrations on coagulation of suspended solids within water purification allows expanding their scope of implementation. The objective of the research is to estimate the effect of ultrasound on the sedimentation of the suspended solids, to determine of the efficiency of the process in relation to the dose of the coagulant, and to calculate the numerical values of the constants in the theoretical equation. The experiment condition was held in the water with the clay substances before the introduction of the coagulant. The method of magnetostriction ultrasonic generator was applied to receive ultrasonic vibration. Estimate of concentration of clay particles in water was performed using photometry. As a result of the research, the obtained data allow determining the increase in efficiency of suspended particles sedimentation related to the dose of coagulant, depending on time of ultrasonic treatment. The experiments confirmed the connection between the effect of sedimentation in the coagulation process, the coagulant dose and the time of scoring. Studies have shown that the increase in the duration of ultrasonic treatment causes a decrease of administered doses of coagulant.

  3. Flexible suspended gate organic thin-film transistors for ultra-sensitive pressure detection

    Science.gov (United States)

    Zang, Yaping; Zhang, Fengjiao; Huang, Dazhen; Gao, Xike; di, Chong-An; Zhu, Daoben

    2015-03-01

    The utilization of organic devices as pressure-sensing elements in artificial intelligence and healthcare applications represents a fascinating opportunity for the next-generation electronic products. To satisfy the critical requirements of these promising applications, the low-cost construction of large-area ultra-sensitive organic pressure devices with outstanding flexibility is highly desired. Here we present flexible suspended gate organic thin-film transistors (SGOTFTs) as a model platform that enables ultra-sensitive pressure detection. More importantly, the unique device geometry of SGOTFTs allows the fine-tuning of their sensitivity by the suspended gate. An unprecedented sensitivity of 192 kPa-1, a low limit-of-detection pressure of <0.5 Pa and a short response time of 10 ms were successfully realized, allowing the real-time detection of acoustic waves. These excellent sensing properties of SGOTFTs, together with their advantages of facile large-area fabrication and versatility in detecting various pressure signals, make SGOTFTs a powerful strategy for spatial pressure mapping in practical applications.

  4. Pressure Sensitive Insulated Gate Field Effect Transistor

    Science.gov (United States)

    Suminto, James Tjan-Meng

    A pressure sensitive insulated gate field effect transistor has been developed. The device is an elevated gate field-effect-transistor. It consists of a p-type silicon substrate in which two n^+ region, the source and drain, are formed. The gate electrode is a metal film sandwiched in an insulated micro-diaphragm resembling a pill-box which covers the gate oxide, drain, and source. The space between the gate electrode and the oxide is vacuum or an air-gap. When pressure is applied on the diaphragm it deflects and causes a change in the gate capacitance, and thus modulates the conductance of the channel between source and drain. A general theory dealing with the characteristic of this pressure sensitive insulated gate field effect transistor has been derived, and the device fabricated. The fabrication process utilizes the standard integrated circuit fabrication method. It features a batch fabrication of field effect devices followed by the batch fabrication of the deposited diaphragm on top of each field effect device. The keys steps of the diaphragm fabrication are the formation of spacer layer, formation of the diaphragm layer, and the subsequent removal of the spacer layer. The chip size of the device is 600 μm x 1050 mum. The diaphragm size is 200 μm x 200 mum. Characterization of the device has been performed. The current-voltage characteristics with pressure as parameters have been demonstrated and the current-pressure transfer curves obtained. They show non-linear characteristics as those of conventional capacitive pressure sensors. The linearity of threshold voltage versus pressure transfer curves has been demonstrated. The temperature effect on the device performances has been tested. The temperature coefficient of threshold voltage, rather than the electron mobility, has dominated the temperature coefficient of the device. Two temperature compensation schemes have been tested: one method is by connecting two identical PSIGFET in a differential amplifier

  5. Gate bias-dependent junction characteristics of silicon nanowires suspended between polysilicon electrodes

    Directory of Open Access Journals (Sweden)

    Yun-Hi Lee and Sungim Park

    2011-01-01

    Full Text Available Realistic integration of 1D materials into future nanodevices is limited by the lack of a manipulation process that allows a large number of nanowires to be arranged into an integrated circuit. In this work, we have grown Si nanowire bridges using a thin-film catalyst in a batch process at 200 °C and characterized the produced devices consisting of a p+-Si contact electrode, a suspended Si nanochannel, and a polysilicon contact electrode. Both the electrodes and connecting lines are made of Si-based materials by conventional low-pressure chemical vapor deposition. The results indicate that these devices can act as gate-controllable Schottky diodes in integrated nanocircuits.

  6. Top-gate pentacene-based organic field-effect transistor with amorphous rubrene gate insulator

    Science.gov (United States)

    Hiroki, Mizuha; Maeda, Yasutaka; Ohmi, Shun-ichiro

    2018-02-01

    The scaling of organic field-effect transistors (OFETs) is necessary for high-density integration and for this, OFETs with a top-gate configuration are required. There have been several reports of damageless lithography processes for organic semiconductor or insulator layers. However, it is still difficult to fabricate scaled OFETs with a top-gate configuration. In this study, the lift-off process and the device characteristics of the OFETs with a top-gate configuration utilizing an amorphous (α) rubrene gate insulator were investigated. We have confirmed that α-rubrene shows an insulating property, and its extracted linear mobility was 2.5 × 10‑2 cm2/(V·s). The gate length and width were 10 and 60 µm, respectively. From these results, the OFET with a top-gate configuration utilizing an α-rubrene gate insulator is promising for the high-density integration of scaled OFETs.

  7. Image Filtering with Field Programmable Gate Array

    Directory of Open Access Journals (Sweden)

    Arūnas Šlenderis

    2013-05-01

    Full Text Available The research examined the use of field programmable gate arrays (FPGA in image filtering. Experimental and theoretical researches were reviewed. Experiments with Cyclone III family FPGA chip with implemented NIOS II soft processor were considered. Image filtering was achieved with symmetrical and asymmetrical finite impulse response filters with convolution kernel. The system, which was implemented with 3×3 symmetrical filter, which was implemented using the hardware description language, uses 59% of logic elements of the chip and 10 multiplication elements. The system with asymmetrical filter uses the same amount of logic elements and 13 multiplication elements. Both filter systems consume approx. 545 mW of power. The system, which is designed for filter implementation in C language, uses 65% of all logical elements and consumes 729 mW of power.Article in Lithuanian

  8. Probing Dense Sprays with Gated, Picosecond, Digital Particle Field Holography

    Directory of Open Access Journals (Sweden)

    James Trolinger

    2011-12-01

    Full Text Available This paper describes work that demonstrated the feasibility of producing a gated digital holography system that is capable of producing high-resolution images of three-dimensional particle and structure details deep within dense particle fields of a spray. We developed a gated picosecond digital holocamera, using optical Kerr cell gating, to demonstrate features of gated digital holography that make it an exceptional candidate for this application. The Kerr cell gate shuttered the camera after the initial burst of ballistic and snake photons had been recorded, suppressing longer path, multiple scattered illumination. By starting with a CW laser without gating and then incorporating a picosecond laser and an optical Kerr gate, we were able to assess the imaging quality of the gated holograms, and determine improvement gained by gating. We produced high quality images of 50–200 μm diameter particles, hairs and USAF resolution charts from digital holograms recorded through turbid media where more than 98% of the light was scattered from the field. The system can gate pulses as short as 3 mm in pathlength (10 ps, enabling image-improving features of the system. The experiments lead us to the conclusion that this method has an excellent capability as a diagnostics tool in dense spray combustion research.

  9. Graphene field effect transistors with parylene gate dielectric

    Science.gov (United States)

    Sabri, S. S.; Lévesque, P. L.; Aguirre, C. M.; Guillemette, J.; Martel, R.; Szkopek, T.

    2009-12-01

    We report the fabrication and characterization of graphene field effect transistors with parylene back gate and exposed graphene top surface. A back gate stack of 168 nm parylene on 94 nm thermal silicon oxide permitted optical reflection microscopy to be used for identifying exfoliated graphene flakes. Room temperature mobilities of 10 000 cm2/Vs at 1012/cm2 electron/hole densities were observed in electrically contacted graphene. Parylene gated devices exhibited stable neutrality point gate voltage under ambient conditions and less hysteresis than that observed in graphene flakes directly exfoliated on silicon oxide.

  10. High mobility polymer gated organic field effect transistor using zinc ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 37; Issue 1. High mobility polymer gated organic field effect transistor using zinc ... fabricated using evaporated zinc phthalocyanine as the active layer. Parylene film prepared by chemical vapour deposition was used as the organic gate insulator. The annealing of the ...

  11. High-field electrical and thermal transport in suspended graphene.

    Science.gov (United States)

    Dorgan, Vincent E; Behnam, Ashkan; Conley, Hiram J; Bolotin, Kirill I; Pop, Eric

    2013-10-09

    We study the intrinsic transport properties of suspended graphene devices at high fields (≥1 V/μm) and high temperatures (≥1000 K). Across 15 samples, we find peak (average) saturation velocity of 3.6 × 10(7) cm/s (1.7 × 10(7) cm/s) and peak (average) thermal conductivity of 530 W m(-1) K(-1) (310 W m(-1) K(-1)) at 1000 K. The saturation velocity is 2-4 times and the thermal conductivity 10-17 times greater than in silicon at such elevated temperatures. However, the thermal conductivity shows a steeper decrease at high temperature than in graphite, consistent with stronger effects of second-order three-phonon scattering. Our analysis of sample-to-sample variation suggests the behavior of "cleaner" devices most closely approaches the intrinsic high-field properties of graphene. This study reveals key features of charge and heat flow in graphene up to device breakdown at ~2230 K in vacuum, highlighting remaining unknowns under extreme operating conditions.

  12. Experimental 3D Asynchronous Field Programmable Gate Array (FPGA)

    Science.gov (United States)

    2015-03-01

    EXPERIMENTAL 3D ASYNCHRONOUS FIELD PROGRAMMABLE GATE ARRAY ( FPGA ) CORNELL UNIVERSITY MARCH 2015 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC...From - To) OCT 2011 – OCT 2014 4. TITLE AND SUBTITLE EXPERIMENTAL 3D ASYNCHRONOUS FIELD PROGRAMMABLE GATE ARRAY ( FPGA ) 5a. CONTRACT NUMBER...in collaboration with Albany’s College of Nanoscale Science and Engineering. 15. SUBJECT TERMS 3D Technology, vertical interconnects, AFPGA, FPGA

  13. Integration of biomolecular logic gates with field-effect transducers

    Energy Technology Data Exchange (ETDEWEB)

    Poghossian, A., E-mail: a.poghossian@fz-juelich.de [Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, Campus Juelich, Heinrich-Mussmann-Str. 1, D-52428 Juelich (Germany); Institute of Bio- and Nanosystems, Research Centre Juelich GmbH, D-52425 Juelich (Germany); Malzahn, K. [Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, Campus Juelich, Heinrich-Mussmann-Str. 1, D-52428 Juelich (Germany); Abouzar, M.H. [Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, Campus Juelich, Heinrich-Mussmann-Str. 1, D-52428 Juelich (Germany); Institute of Bio- and Nanosystems, Research Centre Juelich GmbH, D-52425 Juelich (Germany); Mehndiratta, P. [Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, Campus Juelich, Heinrich-Mussmann-Str. 1, D-52428 Juelich (Germany); Katz, E. [Department of Chemistry and Biomolecular Science, NanoBio Laboratory (NABLAB), Clarkson University, Potsdam, NY 13699-5810 (United States); Schoening, M.J. [Institute of Nano- and Biotechnologies, Aachen University of Applied Sciences, Campus Juelich, Heinrich-Mussmann-Str. 1, D-52428 Juelich (Germany); Institute of Bio- and Nanosystems, Research Centre Juelich GmbH, D-52425 Juelich (Germany)

    2011-11-01

    Highlights: > Enzyme-based AND/OR logic gates are integrated with a capacitive field-effect sensor. > The AND/OR logic gates compose of multi-enzyme system immobilised on sensor surface. > Logic gates were activated by different combinations of chemical inputs (analytes). > The logic output (pH change) produced by the enzymes was read out by the sensor. - Abstract: The integration of biomolecular logic gates with field-effect devices - the basic element of conventional electronic logic gates and computing - is one of the most attractive and promising approaches for the transformation of biomolecular logic principles into macroscopically useable electrical output signals. In this work, capacitive field-effect EIS (electrolyte-insulator-semiconductor) sensors based on a p-Si-SiO{sub 2}-Ta{sub 2}O{sub 5} structure modified with a multi-enzyme membrane have been used for electronic transduction of biochemical signals processed by enzyme-based OR and AND logic gates. The realised OR logic gate composes of two enzymes (glucose oxidase and esterase) and was activated by ethyl butyrate or/and glucose. The AND logic gate composes of three enzymes (invertase, mutarotase and glucose oxidase) and was activated by two chemical input signals: sucrose and dissolved oxygen. The developed integrated enzyme logic gates produce local pH changes at the EIS sensor surface as a result of biochemical reactions activated by different combinations of chemical input signals, while the pH value of the bulk solution remains unchanged. The pH-induced charge changes at the gate-insulator (Ta{sub 2}O{sub 5}) surface of the EIS transducer result in an electronic signal corresponding to the logic output produced by the immobilised enzymes. The logic output signals have been read out by means of a constant-capacitance method.

  14. Tunnel field-effect transistor with two gated intrinsic regions

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2014-07-01

    Full Text Available In this paper, we propose and validate (using simulations a novel design of silicon tunnel field-effect transistor (TFET, based on a reverse-biased p+-p-n-n+ structure. 2D device simulation results show that our devices have significant improvements of switching performance compared with more conventional devices based on p-i-n structure. With independent gate voltages applied to two gated intrinsic regions, band-to-band tunneling (BTBT could take place at the p-n junction, and no abrupt degenerate doping profile is required. We developed single-side-gate (SSG structure and double-side-gate (DSG structure. SSG devices with HfO2 gate dielectric have a point subthreshold swing of 9.58 mV/decade, while DSG devices with polysilicon gate electrode material and HfO2 gate dielectric have a point subthreshold swing of 16.39 mV/decade. These DSG devices have ON-current of 0.255 μA/μm, while that is lower for SSG devices. Having two nano-scale independent gates will be quite challenging to realize with good uniformity across the wafer and the improved behavior of our TFET makes it a promising steep-slope switch candidate for further investigations.

  15. Nonlinear properties of gated graphene in a strong electromagnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Avetisyan, A. A., E-mail: artakav@ysu.am; Djotyan, A. P., E-mail: adjotyan@ysu.am [Yerevan State University, Department of Physics (Armenia); Moulopoulos, K., E-mail: cos@ucy.ac.cy [University of Cyprus, Department of Physics (Cyprus)

    2017-03-15

    We develop a microscopic theory of a strong electromagnetic field interaction with gated bilayer graphene. Quantum kinetic equations for density matrix are obtained using a tight binding approach within second quantized Hamiltonian in an intense laser field. We show that adiabatically changing the gate potentials with time may produce (at resonant photon energy) a full inversion of the electron population with high density between valence and conduction bands. In the linear regime, excitonic absorption of an electromagnetic radiation in a graphene monolayer with opened energy gap is also studied.

  16. Optical Doppler tomography based on a field programmable gate array

    DEFF Research Database (Denmark)

    Larsen, Henning Engelbrecht; Nilsson, Ronnie Thorup; Thrane, Lars

    2008-01-01

    We report the design of and results obtained by using a field programmable gate array (FPGA) to digitally process optical Doppler tomography signals. The processor fits into the analog signal path in an existing optical coherence tomography setup. We demonstrate both Doppler frequency and envelope...

  17. High mobility polymer gated organic field effect transistor using zinc ...

    Indian Academy of Sciences (India)

    Mater. Sci., Vol. 37, No. 1, February 2014, pp. 95–99. c Indian Academy of Sciences. High mobility polymer gated organic field effect transistor using zinc phthalocyanine. K R RAJESH. ∗. , V KANNAN, M R KIM, Y S CHAE and J K RHEE. Millimeter- Wave Innovation Technology Research Centre (MINT), Dongguk University,.

  18. Introduction to embedded system design using field programmable gate arrays

    CERN Document Server

    Dubey, Rahul

    2009-01-01

    Offers information on the use of field programmable gate arrays (FPGAs) in the design of embedded systems. This text considers a hypothetical robot controller as an embedded application and weaves around it related concepts of FPGA-based digital design. It is suitable for both students and designers who have worked with microprocessors.

  19. Inversion gate capacitance of undoped single-gate and double-gate field-effect transistor geometries in the extreme quantum limit

    Energy Technology Data Exchange (ETDEWEB)

    Majumdar, Amlan, E-mail: amajumd@us.ibm.com [IBM Research Division, T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

    2015-05-28

    We present first-principle analytical derivations and numerically modeled data to show that the gate capacitance per unit gate area C{sub G} of extremely thin undoped-channel single-gate and double-gate field-effect transistor geometries in the extreme quantum limit with single-subband occupancy can be written as 1/C{sub G} = 1/C{sub OX} + N{sub G}/C{sub DOS} + N{sub G}/ηC{sub WF}, where N{sub G} is the number of gates, C{sub OX} is the oxide capacitance per unit area, C{sub DOS} is the density-of-states capacitance per unit area, C{sub WF} is the wave function spreading capacitance per unit area, and η is a constant on the order of 1.

  20. Field calibration of optical sensors for measuring suspended sediment concentration in the western Mediterranean

    Directory of Open Access Journals (Sweden)

    J. Guillén

    2000-12-01

    Full Text Available The water turbidity measured with optical methods (transmittance and backscattering is usually expressed as beam attenuation coefficient (BAC or formazin turbidity units (FTU. The transformation of these units to volumetric suspended sediment concentration (SSC units is not straightforward, and accurate calibrations are required in order to obtain valuable information on suspended sediment distributions and fluxes. In this paper, data from field calibrations between BAC, FTU and SSC are presented and best-fit calibration curves are shown. These calibrations represent an average from different marine environments of the western Mediterranean (from estuary to continental slope. However, the general curves can only be applied for descriptive or semi-quantitative purposes. Comparison of turbidity measurements using the same sensor with different calibration ranges shows the advantage of simultaneously combining two instruments calibrated in different ranges when significant changes in suspended sediment concentrations are expected.

  1. Analyses of Short Channel Effects of Single-Gate and Double-Gate Graphene Nanoribbon Field Effect Transistors

    Directory of Open Access Journals (Sweden)

    Hojjatollah Sarvari

    2016-01-01

    Full Text Available Short channel effects of single-gate and double-gate graphene nanoribbon field effect transistors (GNRFETs are studied based on the atomistic pz orbital model for the Hamiltonian of graphene nanoribbon using the nonequilibrium Green’s function formalism. A tight-binding Hamiltonian with an atomistic pz orbital basis set is used to describe the atomistic details in the channel of the GNRFETs. We have investigated the vital short channel effect parameters such as Ion and Ioff, the threshold voltage, the subthreshold swing, and the drain induced barrier lowering versus the channel length and oxide thickness of the GNRFETs in detail. The gate capacitance and the transconductance of both devices are also computed in order to calculate the intrinsic cut-off frequency and switching delay of GNRFETs. Furthermore, the effects of doping of the channel on the threshold voltage and the frequency response of the double-gate GNRFET are discussed. We have shown that the single-gate GNRFET suffers more from short channel effects if compared with those of the double-gate structure; however, both devices have nearly the same cut-off frequency in the range of terahertz. This work provides a collection of data comparing different features of short channel effects of the single gate with those of the double gate GNRFETs. The results give a very good insight into the devices and are very useful for their digital applications.

  2. Suspended sediment diffusion mechanisms in the Yangtze Estuary influenced by wind fields

    Science.gov (United States)

    Wang, Lihua; Zhou, Yunxuan; Shen, Fang

    2018-01-01

    The complexity of suspended sediment concentration (SSC) distribution and diffusion has been widely recognized because it is influenced by sediment supply and various hydrodynamic forcing conditions that vary over space and over time. Sediment suspended by waves and transported by currents are the dominant sediment transport mechanisms in estuarine and coastal areas. However, it is unclear to what extent the SSC distribution is impacted by each hydrodynamic factor. Research on the quantitative influence of wind fields on the SSC diffusion range will contribute to a better understanding of the characteristics of sediment transport change and sedimentary geomorphic evolution. This study determined SSC from three Envisat Medium-Resolution Imaging Spectrometer acquisitions, covering the Yangtze Estuary and adjacent water area under the same season and tidal conditions but with varying wind conditions. SSC was examined based on the Semi-Empirical Radiative Transfer model, which has been well validated with the observation data. Integrating the corresponding wind field information from European Centre for Medium-Range Weather Forecasts further facilitated the discussion of wind fields affecting SSC, and in turn the influence of water and suspended sediment transportation and diffusion in the Yangtze estuarine and coastal area. The results demonstrated that the SSC present much more distinctive fluvial features in the inner estuary and wind fields are one of the major factors controlling the range of turbid water diffusion.

  3. Electric-field control of ferromagnetism through oxygen ion gating.

    Science.gov (United States)

    Li, Hao-Bo; Lu, Nianpeng; Zhang, Qinghua; Wang, Yujia; Feng, Deqiang; Chen, Tianzhe; Yang, Shuzhen; Duan, Zheng; Li, Zhuolu; Shi, Yujun; Wang, Weichao; Wang, Wei-Hua; Jin, Kui; Liu, Hui; Ma, Jing; Gu, Lin; Nan, Cewen; Yu, Pu

    2017-12-18

    Electric-field-driven oxygen ion evolution in the metal/oxide heterostructures emerges as an effective approach to achieve the electric-field control of ferromagnetism. However, the involved redox reaction of the metal layer typically requires extended operation time and elevated temperature condition, which greatly hinders its practical applications. Here, we achieve reversible sub-millisecond and room-temperature electric-field control of ferromagnetism in the Co layer of a Co/SrCoO2.5 system accompanied by bipolar resistance switching. In contrast to the previously reported redox reaction scenario, the oxygen ion evolution occurs only within the SrCoO2.5 layer, which serves as an oxygen ion gating layer, leading to modulation of the interfacial oxygen stoichiometry and magnetic state. This work identifies a simple and effective pathway to realize the electric-field control of ferromagnetism at room temperature, and may lead to applications that take advantage of both the resistance switching and magnetoelectric coupling.

  4. Threshold voltage modeling and performance comparison of a novel linearly graded binary metal alloy gate junctionless double gate metal oxide semiconductor field effect transistor

    Science.gov (United States)

    Sarkhel, S.; Manna, B.; Sarkar, S. K.

    2015-06-01

    Keeping pace with the current research trend dominated by development of junctionless devices, in this work, we have incorporated the innovative concept of work function engineering by continuous horizontal variation of mole fraction in a binary metal alloy gate into a junctionless double gate metal oxide semiconductor field effect transistor. We have thereby presented a new structure, a junctionless work function engineered gate double gate metal oxide semiconductor field effect transistor. A detailed analytical modeling of this novel transistor structure has been done based on the solution of two dimensional Poisson's equation presenting a simplified expression for short channel threshold voltage. Based on analytical calculations, an overall performance comparison of junctionless work function engineered gate double gate and normal junctionless double gate metal oxide semiconductor field effect transistor has been investigated to establish the superiority of our proposed structure over its normal junctionless double gate counterpart in terms of reduced short channel effects, threshold voltage roll-off and drain induced barrier lowering.

  5. Enhanced transconductance in a double-gate graphene field-effect transistor

    Science.gov (United States)

    Hwang, Byeong-Woon; Yeom, Hye-In; Kim, Daewon; Kim, Choong-Ki; Lee, Dongil; Choi, Yang-Kyu

    2018-03-01

    Multi-gate transistors, such as double-gate, tri-gate and gate-all-around transistors are the most advanced Si transistor structure today. Here, a genuine double-gate transistor with a graphene channel is experimentally demonstrated. The top and bottom gates of the double-gate graphene field-effect transistor (DG GFET) are electrically connected so that the conductivity of the graphene channel can be modulated simultaneously by both the top and bottom gate. A single-gate graphene field-effect transistor (SG GFET) with only the top gate is also fabricated as a control device. For systematical analysis, the transfer characteristics of both GFETs were measured and compared. Whereas the maximum transconductance of the SG GFET was 17.1 μS/μm, that of the DG GFET was 25.7 μS/μm, which is approximately a 50% enhancement. The enhancement of the transconductance was reproduced and comprehensively explained by a physics-based compact model for GFETs. The investigation of the enhanced transfer characteristics of the DG GFET in this work shows the possibility of a multi-gate architecture for high-performance graphene transistor technology.

  6. Acoustic backscatter by suspended cohesive sediments: Field observations, Seine Estuary, France

    Science.gov (United States)

    Sahin, Cihan; Verney, Romaric; Sheremet, Alexandru; Voulgaris, George

    2017-02-01

    Observations of suspended sediment size and concentration, flow and acoustic backscatter intensity collected on the Seine Estuary (France) are used to study the acoustic response in cohesive-sediment dominated environments. Estimates of suspended sediment concentration based on optical backscatter sensors and water samples are used to calibrate the acoustic backscatter intensity. The vertical structure of suspended sediment concentration is then estimated from acoustic backscatter information. To our knowledge, this is the first field application of the recently proposed model of acoustic scattering by flocculating suspensions based on the variation of particle density (floc-scattering model). The estimates of sediment concentration reproduce well the observations under different tidal (neap/spring) conditions, confirming the applicability of the new model in the field when detailed particle size measurements are available. When particle size measurements are not available, using estimated floc sizes based on the turbulence intensities may provide reasonable SSC profiles. During spring tide events (associated with strong currents, small flocs and large concentrations), the performances of the new floc-scattering model and the previous models given for solid particle-scattering are comparable. The floc-scattering model increases the quality of the SSC estimates especially during low-energy conditions characterized with larger flocs.

  7. IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field (IMFGM0) data set contains magnetic field readings taken over Antarctica using the Integrity...

  8. IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Flux Gate Magnetometer L0 Raw Magnetic Field (IMFGM0) data set contains magnetic field readings taken over Antarctica using the Integrity...

  9. Deformation and burst of a liquid droplet freely suspended in a linear shear field

    Science.gov (United States)

    Barthes-Biesel, D.; Acrivos, A.

    1973-01-01

    A theoretical method is presented for predicting the deformation and the conditions for breakup of a liquid droplet freely suspended in a general linear shear field. This is achieved by expanding the solution to the creeping-flow equations in powers of the deformation parameter epsilon and using linear stability theory to determine the onset of bursting. When compared with numerical solutions and with the available experimental data, the theoretical results are generally found to be of acceptable accuracy although, in some cases, the agreement is only qualitative.

  10. Range-gated imaging for near-field target identification

    Energy Technology Data Exchange (ETDEWEB)

    Yates, G.J.; Gallegos, R.A.; McDonald, T.E. [and others

    1996-12-01

    The combination of two complementary technologies developed independently at Los Alamos National Laboratory (LANL) and Sandia National Laboratory (SNL) has demonstrated feasibility of target detection and image capture in a highly light-scattering, medium. The technique uses a compact SNL developed Photoconductive Semiconductor Switch/Laser Diode Array (PCSS/LDA) for short-range (distances of 8 to 10 m) large Field-Of-View (FOV) target illumination. Generation of a time-correlated echo signal is accomplished using a photodiode. The return image signal is recorded with a high-speed shuttered Micro-Channel-Plate Image Intensifier (MCPII), declined by LANL and manufactured by Philips Photonics. The MCPII is rated using a high-frequency impedance-matching microstrip design to produce 150 to 200 ps duration optical exposures. The ultra first shuttering producer depth resolution of a few inches along the optic axis between the MCPII and the target, producing enhanced target images effectively deconvolved from noise components from the scattering medium in the FOV. The images from the MCPII are recorded with an RS-170 Charge-Coupled-Device camera and a Big Sky, Beam Code, PC-based digitizer frame grabber and analysis package. Laser pulse data were obtained by the but jitter problems and spectral mismatches between diode spectral emission wavelength and MCPII photocathode spectral sensitivity prevented the capture of fast gating imaging with this demonstration system. Continued development of the system is underway.

  11. Infrared light gated MoS₂ field effect transistor.

    Science.gov (United States)

    Fang, Huajing; Lin, Ziyuan; Wang, Xinsheng; Tang, Chun-Yin; Chen, Yan; Zhang, Fan; Chai, Yang; Li, Qiang; Yan, Qingfeng; Chan, H L W; Dai, Ji-Yan

    2015-12-14

    Molybdenum disulfide (MoS₂) as a promising 2D material has attracted extensive attentions due to its unique physical, optical and electrical properties. In this work, we demonstrate an infrared (IR) light gated MoS₂ transistor through a device composed of MoS₂ monolayer and a ferroelectric single crystal Pb(Mg(1/3)Nb(2/3))O₃-PbTiO₃ (PMN-PT). With a monolayer MoS₂ onto the top surface of (111) PMN-PT crystal, the drain current of MoS₂ channel can be modulated with infrared illumination and this modulation process is reversible. Thus, the transistor can work as a new kind of IR photodetector with a high IR responsivity of 114%/Wcm⁻². The IR response of MoS₂ transistor is attributed to the polarization change of PMN-PT single crystal induced by the pyroelectric effect which results in a field effect. Our result promises the application of MoS₂ 2D material in infrared optoelectronic devices. Combining with the intrinsic photocurrent feature of MoS₂ in the visible range, the MoS₂ on ferroelectric single crystal may be sensitive to a broadband wavelength of light.

  12. Calibration of a turbidity meter for making estimates of total suspended solids concentrations and beam attenuation coefficients in field experiments

    Science.gov (United States)

    Usry, J. W.; Whitlock, C. H.

    1981-01-01

    Management of water resources such as a reservoir requires using analytical models which describe such parameters as the suspended sediment field. To select or develop an appropriate model requires making many measurements to describe the distribution of this parameter in the water column. One potential method for making those measurements expeditiously is to measure light transmission or turbidity and relate that parameter to total suspended solids concentrations. An instrument which may be used for this purpose was calibrated by generating curves of transmission measurements plotted against measured values of total suspended solids concentrations and beam attenuation coefficients. Results of these experiments indicate that field measurements made with this instrument using curves generated in this study should correlate with total suspended solids concentrations and beam attenuation coefficients in the water column within 20 percent.

  13. Measurement method of magnetic field for the wire suspended micro-pendulum accelerometer.

    Science.gov (United States)

    Lu, Yongle; Li, Leilei; Hu, Ning; Pan, Yingjun; Ren, Chunhua

    2015-04-13

    Force producer is one of the core components of a Wire Suspended Micro-Pendulum Accelerometer; and the stability of permanent magnet in the force producer determines the consistency of the acceleration sensor's scale factor. For an assembled accelerometer; direct measurement of magnetic field strength is not a feasible option; as the magnetometer probe cannot be laid inside the micro-space of the sensor. This paper proposed an indirect measurement method of the remnant magnetization of Micro-Pendulum Accelerometer. The measurement is based on the working principle of the accelerometer; using the current output at several different scenarios to resolve the remnant magnetization of the permanent magnet. Iterative Least Squares algorithm was used for the adjustment of the data due to nonlinearity of this problem. The calculated remnant magnetization was 1.035 T. Compared to the true value; the error was less than 0.001 T. The proposed method provides an effective theoretical guidance for measuring the magnetic field of the Wire Suspended Micro-Pendulum Accelerometer; correcting the scale factor and temperature influence coefficients; etc.

  14. Measurement Method of Magnetic Field for the Wire Suspended Micro-Pendulum Accelerometer

    Directory of Open Access Journals (Sweden)

    Yongle Lu

    2015-04-01

    Full Text Available Force producer is one of the core components of a Wire Suspended Micro-Pendulum Accelerometer; and the stability of permanent magnet in the force producer determines the consistency of the acceleration sensor’s scale factor. For an assembled accelerometer; direct measurement of magnetic field strength is not a feasible option; as the magnetometer probe cannot be laid inside the micro-space of the sensor. This paper proposed an indirect measurement method of the remnant magnetization of Micro-Pendulum Accelerometer. The measurement is based on the working principle of the accelerometer; using the current output at several different scenarios to resolve the remnant magnetization of the permanent magnet. Iterative Least Squares algorithm was used for the adjustment of the data due to nonlinearity of this problem. The calculated remnant magnetization was 1.035 T. Compared to the true value; the error was less than 0.001 T. The proposed method provides an effective theoretical guidance for measuring the magnetic field of the Wire Suspended Micro-Pendulum Accelerometer; correcting the scale factor and temperature influence coefficients; etc.

  15. Leakage and field emission in side-gate graphene field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Di Bartolomeo, A., E-mail: dibant@sa.infn.it; Iemmo, L.; Romeo, F.; Cucolo, A. M. [Physics Department “E.R. Caianiello,” University of Salerno, via G. Paolo II, 84084 Fisciano (Italy); CNR-SPIN Salerno, via G. Paolo II, 84084 Fisciano (Italy); Giubileo, F. [CNR-SPIN Salerno, via G. Paolo II, 84084 Fisciano (Italy); Russo, S.; Unal, S. [Physics Department, University of Exeter, Stocker Road 6, Exeter, Devon EX4 4QL (United Kingdom); Passacantando, M.; Grossi, V. [Department of Physical and Chemical Sciences, University of L' Aquila, Via Vetoio, 67100 Coppito, L' Aquila (Italy)

    2016-07-11

    We fabricate planar graphene field-effect transistors with self-aligned side-gate at 100 nm from the 500 nm wide graphene conductive channel, using a single lithographic step. We demonstrate side-gating below 1 V with conductance modulation of 35% and transconductance up to 0.5 mS/mm at 10 mV drain bias. We measure the planar leakage along the SiO{sub 2}/vacuum gate dielectric over a wide voltage range, reporting rapidly growing current above 15 V. We unveil the microscopic mechanisms driving the leakage, as Frenkel-Poole transport through SiO{sub 2} up to the activation of Fowler-Nordheim tunneling in vacuum, which becomes dominant at higher voltages. We report a field-emission current density as high as 1 μA/μm between graphene flakes. These findings are important for the miniaturization of atomically thin devices.

  16. Gate induced superconductivity in layered material based electronic double layer field effect transistors

    NARCIS (Netherlands)

    Ye, J. T.; Inoue, S.; Kobayashi, K.; Kasahara, Y.; Yuan, H. T.; Shimotani, H.; Iwasa, Y.

    2010-01-01

    Applying the principle of field effect transistor to layered materials provides new opportunities to manipulate their electronic properties for interesting sciences and applications. Novel gate dielectrics like electronic double layer (EDL) formed by ionic liquids are demonstrated to achieve an

  17. Determination of the Runoff and Suspended Sediment from Two Different Slope Length Using Field Plots

    Directory of Open Access Journals (Sweden)

    Hüseyin Şensoy

    2013-11-01

    Full Text Available In this study, the effect of slope length on runoff and suspended sediment yield has been investigated by using plots on uniform slopes under natural rainfall conditions. From September 2007 to September 2009, during two year-period, measurements were done in Dallıca village experimental area in Bartın province. In this study, six field plots with a width of 1.87 m were used. Three of them were 5.5 m long (short plots and remaining three were 11.05 m long (long plots. Plots were located on bare soil surface that has no conservative vegetation. During the period of experimentation, a total of 158 rainy days were registered and average annual rainfall amount was 1194.8 mm. Average annual runoff per square meter was 270.81 mm, and 311.27 mm in long and short plots, respectively. Average annual suspended sediment was 809.68 g m-2, and 766.53 g m-2 from long and short plots, respectively. While statistically significant differences were found in runoff amount from plots with different lengths, there were no statistically significant differences in terms of the amount of eroded sediment.

  18. Total ionizing dose effects in multiple-gate field-effect transistor

    Science.gov (United States)

    Gaillardin, Marc; Marcandella, Claude; Martinez, Martial; Raine, Mélanie; Paillet, Philippe; Duhamel, Olivier; Richard, Nicolas

    2017-08-01

    This paper focuses on total ionizing dose (TID) effects induced in multiple-gate field-effect transistors. The impact of device architecture, geometry and scaling on the TID response of multiple-gate transistors is reviewed in both bulk and silicon-on-insulator (SOI) complementary metal-oxide-semiconductor (CMOS) technologies. These innovating devices exhibit specific ionizing dose responses which strongly depend on their three-dimensional nature. Their TID responses may look like the one usually observed in planar two-dimensional bulk or SOI transistors, but multiple-gate devices can also behave like any other CMOS device.

  19. Fabrication of fin field-effect transistor silicon nanocrystal floating gate memory using photochemical vapor deposition

    Science.gov (United States)

    Kim, Sang Soo; Cho, Won-Ju; Ahn, Chang-Geun; Im, Kiju; Yang, Jong-Heon; Baek, In-Bok; Lee, Seongjae; Lim, Koeng Su

    2006-05-01

    The fin field-effect transistor (FET) silicon nanocrystal floating gate memory using the photochemical vapor deposition and the plasma doping processes was proposed. The silicon nanocrystals with a uniform size were formed on a vertical sidewall surface of the fin channel by the photochemical vapor deposition. The plasma doping was applied to form the junctions at the sidewall of the fin source-drain extension regions with a high aspect ratio. The FinFET silicon nanocrystal floating gate memory with a gate length of 100nm was successfully fabricated and it revealed a memory effect as well as a suppressed short-channel effect.

  20. Simulation of Strain Induced Pseudomagnetic Fields in Graphene Suspended on MEMS Chevron Actuators

    Science.gov (United States)

    Vutukuru, Mounika; Christopher, Jason; Bishop, David; Swan, Anna

    Graphene has been shown to withstand remarkable levels of mechanical strain an order of magnitude larger than bulk crystalline materials. This exceptional stretchability of graphene allows for the direct tuning of fundamental material properties, as well as for the investigation of novel physics such as generation of strain induced pseudomagnetic fields. However, current methods for strain such as polymer elongation or pressurized wells do not integrate well into devices. We propose microelectromechanical (MEMS) Chevron actuators as a reliable platform for applying strain to graphene. In addition to their advantageous controllable output force, low input power and ease of integration into existing technologies, MEMS allow for different strain orientations to optimize pseudomagnetic field generation in graphene. Here, we model nonuniform strain in suspended graphene on Chevron actuators using COMSOL Multiphysics. By simulating the deformation of the graphene geometry under the device actuation, we explore the pseudomagnetic field map induced by numerically calculating the components of the strain tensor. Our models provide the theoretical framework with which experimental analysis is compared, and optimize our MEMS designs for further exploration of novel physics in graphene. The authors would like to thank NSF DMR 1411008 for their support on this project.

  1. Novel three-state quantum dot gate field effect transistor fabrication, modeling and applications

    CERN Document Server

    Karmakar, Supriya

    2014-01-01

    The book presents the fabrication and circuit modeling of quantum dot gate field effect transistor (QDGFET) and quantum dot gate NMOS inverter (QDNMOS inverter). It also introduces the development of a circuit model of QDGFET based on Berkley Short Channel IGFET model (BSIM). Different ternary logic circuits based on QDGFET are also investigated in this book. Advanced circuit such as three-bit and six bit analog-to-digital converter (ADC) and digital-to-analog converter (DAC) were also simulated.

  2. Strain-induced modulation on phonon and electronic properties of suspended black phosphorus field effect transistor

    Science.gov (United States)

    Zheng, Bo; Si, Naichao; Xie, Guoxin; Wang, Quan

    2017-02-01

    Black phosphorus has recently appeared as a promising two-dimensional material for applications in high performance nanoelectronics. Its single- and few-atomic layer forms in field-effect transistors have attracted a lot of attention due to the tunable bandgap (0.3-2.0 eV), high carrier mobility (1000 cm2 V-1 s-1) and decent on-off ratios (105). Here, we demonstrate a suspended black phosphorus field effect transistor (BP-FET) and utilize Raman spectroscope to characterize the strain on the effects of Raman phonon. We find that red shifts appear in all the three vibrational modes (Ag1 , B2g and Ag2) in different degrees. Among them, Ag1 mode is most sensitive to the tensile strain. We further investigate the electronic properties with a Cascade semi-automatic probe station. The linear relationships in the output curves indicate the contacts between black phosphorus and electrodes are ohmic contacts. The transfer characteristic curves declare the drain current modulation is ∼ 7.6 ×103 for the hole conduction and ∼57 for the electron conduction. Mobility of this device is found to be 347.5 cm2 V-1 s-1 and 4.9 cm2 V-1 s-1 for the hole and electron conduction, respectively. These results provide a theoretical basis for the coordination of high-performance black phosphorus electronic components.

  3. Insights into operation of planar tri-gate tunnel field effect transistor for dynamic memory application

    Science.gov (United States)

    Navlakha, Nupur; Kranti, Abhinav

    2017-07-01

    Insights into device physics and operation through the control of energy barriers are presented for a planar tri-gate Tunnel Field Effect Transistor (TFET) based dynamic memory. The architecture consists of a double gate (G1) at the source side and a single gate (G2) at the drain end of the silicon film. Dual gates (G1) effectively enhance the tunneling based read mechanism through the enhanced coupling and improved electrostatic control over the channel. The single gate (G2) controls the holes in the potential barrier induced through the proper selection of bias and workfunction. The results indicate that the planar tri-gate achieves optimum performance evaluated in terms of two composite metrics (M1 and M2), namely, product of (i) Sense Margin (SM) and Retention Time (RT) i.e., M1 = SM × RT and (ii) Sense Margin and Current Ratio (CR) i.e., M2 = SM × CR. The regulation of barriers created by the gates (G1 and G2) through the optimal use of device parameters leads to better performance metrics, with significant improvement at scaled lengths as compared to other tunneling based dynamic memory architectures. The investigation shows that lengths of G1, G2 and lateral spacing can be scaled down to 25 nm, 50 nm, and 30 nm, respectively, while achieving reasonable values for (M1, M2). The work demonstrates a systematic approach to showcase the advancement in TFET based Dynamic Random Access Memory (DRAM) through the use of planar tri-gate topology at a lower bias value. The concept, design, and operation of planar tri-gate architecture provide valuable viewpoints for TFET based DRAM.

  4. A simple laser locking system based on a field-programmable gate array

    DEFF Research Database (Denmark)

    Jørgensen, Nils Byg; Birkmose, Danny Matthiesen; Trelborg, Kristian

    2016-01-01

    such locking systems. We have developed a frequency stabilization system based on a field-programmable gate array, with emphasis on hardware simplicity, which offers a user-friendly alternative to commercial and previous home-built solutions. Frequency modulation, lock-in detection and a proportional-integral......Frequency stabilization of laser light is crucial in both scientific and industrial applications. Technological developments now allow analog laser stabilization systems to be replaced with digital electronics such as field-programmable gate arrays, which have recently been utilized to develop......-derivative controller are programmed on the field-programmable gate array and only minimal additional components are required to frequency stabilize a laser. The locking system is administered from a host-computer which provides comprehensive, long-distance control through a versatile interface. Various measurements...

  5. Auditory inhibitory gating in medial prefrontal cortex: Single unit and local field potential analysis.

    Science.gov (United States)

    Mears, R P; Klein, A C; Cromwell, H C

    2006-08-11

    Medial prefrontal cortex is a crucial region involved in inhibitory processes. Damage to the medial prefrontal cortex can lead to loss of normal inhibitory control over motor, sensory, emotional and cognitive functions. The goal of the present study was to examine the basic properties of inhibitory gating in this brain region in rats. Inhibitory gating has recently been proposed as a neurophysiological assay for sensory filters in higher brain regions that potentially enable or disable information throughput. This perspective has important clinical relevance due to the findings that gating is dramatically impaired in individuals with emotional and cognitive impairments (i.e. schizophrenia). We used the standard inhibitory gating two-tone paradigm with a 500 ms interval between tones and a 10 s interval between tone pairs. We recorded both single unit and local field potentials from chronic microwire arrays implanted in the medial prefrontal cortex. We investigated short-term (within session) and long-term (between session) variability of auditory gating and additionally examined how altering the interval between the tones influenced the potency of the inhibition. The local field potentials displayed greater variability with a reduction in the amplitudes of the tone responses over both the short and long-term time windows. The decrease across sessions was most intense for the second tone response (test tone) leading to a more robust gating (lower T/C ratio). Surprisingly, single unit responses of different varieties retained similar levels of auditory responsiveness and inhibition in both the short and long-term analysis. Neural inhibition decreased monotonically related to the increase in intertone interval. This change in gating was most consistent in the local field potentials. Subsets of single unit responses did not show the lack of inhibition even for the longer intertone intervals tested (4 s interval). These findings support the idea that the medial

  6. Suspended microfluidics

    OpenAIRE

    Casavant, Benjamin P.; Berthier, Erwin; Theberge, Ashleigh B.; Jean BERTHIER; Montanez-Sauri, Sara I.; Bischel, Lauren L.; Brakke, Kenneth; Hedman, Curtis J.; Bushman, Wade; Keller, Nancy P.; Beebe, David J.

    2013-01-01

    Although the field of microfluidics has made significant progress in bringing new tools to address biological questions, the accessibility and adoption of microfluidics within the life sciences are still limited. Open microfluidic systems have the potential to lower the barriers to adoption, but the absence of robust design rules has hindered their use. Here, we present an open microfluidic platform, suspended microfluidics, that uses surface tension to fill and maintain a fluid in microscale...

  7. Stability Of Superposed Fluids Through Magnetic Field With Suspended Particles Of Different Permeability Saturated Through Porous Layer

    Science.gov (United States)

    Singh, M.

    2015-12-01

    The instability of plane interface between two superposed Rivlin-Ericksen elastico-viscous fluids saturated through a porous medium has been studied to include the suspended (dust) particles effect. Following the linearized stability theory and normal mode analysis the dispersion relation is obtained. For stationary convection, the Rivlin-Ericksen elastico-viscous fluid behaves like Newtonian fluids. It found that for a potentially stable arrangement the Rivlin-Ericksen elastico-viscous fluid of different permeabilities in the presence of suspended particles in a porous medium is stable, whereas in a potentially unstable case instability of the system occurs. In the presence of a magnetic field for a potentially stable arrangement the system is always stable and for the potentially unstable arrangement, the magnetic field succeeds in stabilizing certain wave-number band which was unstable in the absence of the magnetic field.

  8. Electrically configurable graphene field-effect transistors with a graded-potential gate.

    Science.gov (United States)

    Wang, Xiaowei; Jiang, Xingbin; Wang, Ting; Shi, Jia; Liu, Mingju; Zeng, Qibin; Cheng, Zhihai; Qiu, Xiaohui

    2015-05-13

    A device architecture for electrically configurable graphene field-effect transistor (GFET) using a graded-potential gate is present. The gating scheme enables a linearly varying electric field that modulates the electronic structure of graphene and causes a continuous shift of the Dirac points along the channel of GFET. This spatially varying electrostatic modulation produces a pseudobandgap observed as a suppressed conductance of graphene within a controllable energy range. By tuning the electrical gradient of the gate, a GFET device is reversibly transformed between ambipolar and n- and p-type unipolar characteristics. We further demonstrate an electrically programmable complementary inverter, showing the extensibility of the proposed architecture in constructing logic devices based on graphene and other Dirac materials. The electrical configurable GFET might be explored for novel functionalities in smart electronics.

  9. The demonstration of promising Ge n-type multi-gate-field-effect transistors with the magnetic FePt metal gate scheme

    Science.gov (United States)

    Liao, M.-H.; Huang, S. C.

    2015-08-01

    In this work, the tetragonal-phase BaTiO3 high dielectric (HK) layer and the magnetic FePt metal gate (MG) film are proposed to be the gate stack scheme on the Ge three dimensional (3D) n-type multi-gate-field-effect transistors (FETs). The ˜75% dielectric constant (κ-value) improvement, ˜100× gate leakage (Jg) reduction, and ˜70% on-state current (Ion) enhancement are achieved due to the colossal magneto-capacitance effect. The magnetic field from the magnetic FePt MG film couples and triggers more dipoles in the BaTiO3 HK layer and then results in the super gate stack characteristics. The promising transistor's performance (˜200 μA/μm on the device with the gate length Lch = 60 nm) on the high mobility (Ge) material in the 3D n-type multi-gate-FETs device structure demonstrated in this work provides the useful solution for the future advanced logic device design.

  10. A magnetoelectric flux gate: new approach for weak DC magnetic field detection.

    Science.gov (United States)

    Chu, Zhaoqiang; Shi, Huaduo; PourhosseiniAsl, Mohammad Javad; Wu, Jingen; Shi, Weiliang; Gao, Xiangyu; Yuan, Xiaoting; Dong, Shuxiang

    2017-08-17

    The magnetic flux gate sensors based on Faraday's Law of Induction are widely used for DC or extremely low frequency magnetic field detection. Recently, as the fast development of multiferroics and magnetoelectric (ME) composite materials, a new technology based on ME coupling effect is emerging for potential devices application. Here, we report a magnetoelectric flux gate sensor (MEFGS) for weak DC magnetic field detection for the first time, which works on a similar magnetic flux gate principle, but based on ME coupling effect. The proposed MEFGS has a shuttle-shaped configuration made of amorphous FeBSi alloy (Metglas) serving as both magnetic and magnetostrictive cores for producing a closed-loop high-frequency magnetic flux and also a longitudinal vibration, and one pair of embedded piezoelectric PMN-PT fibers ([011]-oriented Pb(Mg,Nb)O3-PbTiO3 single crystal) serving as ME flux gate in a differential mode for detecting magnetic anomaly. In this way, the relative change in output signal of the MEFGS under an applied DC magnetic anomaly of 1 nT was greatly enhanced by a factor of 4 to 5 in comparison with the previous reports. The proposed ME flux gate shows a great potential for magnetic anomaly detections, such as magnetic navigation, magnetic based medical diagnosis, etc.

  11. An Undergraduate Course and Laboratory in Digital Signal Processing with Field Programmable Gate Arrays

    Science.gov (United States)

    Meyer-Base, U.; Vera, A.; Meyer-Base, A.; Pattichis, M. S.; Perry, R. J.

    2010-01-01

    In this paper, an innovative educational approach to introducing undergraduates to both digital signal processing (DSP) and field programmable gate array (FPGA)-based design in a one-semester course and laboratory is described. While both DSP and FPGA-based courses are currently present in different curricula, this integrated approach reduces the…

  12. Functionalization and microfluidic integration of silicon nanowire biologically gated field effect transistors

    DEFF Research Database (Denmark)

    Pfreundt, Andrea; Svendsen, Winnie Edith; Dimaki, Maria

    2016-01-01

    This thesis deals with the development of a novel biosensor for the detection of biomolecules based on a silicon nanowire biologically gated field-effect transistor and its integration into a point-of-care device. The sensor and electrical on-chip integration was developed in a different project...

  13. Functionalization and microfluidic integration of silicon nanowire biologically gated field effect transistors

    DEFF Research Database (Denmark)

    Pfreundt, Andrea

    This thesis deals with the development of a novel biosensor for the detection of biomolecules based on a silicon nanowire biologically gated field-effect transistor and its integration into a point-of-care device. The sensor and electrical on-chip integration was developed in a different project...

  14. Gate-bias assisted charge injection in organic field-effect transistors

    NARCIS (Netherlands)

    Brondijk, J. J.; Torricelli, F.; Smits, E. C. P.; Blom, P. W. M.; de Leeuw, D. M.

    The charge injection barriers in organic field-effect transistors (OFETs) seem to be far less critical as compared to organic light-emitting diodes (OLEDs). Counter intuitively, we show that the origin is image-force lowering of the barrier due to the gate bias at the source contact, although the

  15. Gate-bias assisted charge injection in organic field-effect transistors

    NARCIS (Netherlands)

    Brondijk, J.J.; Torricelli, F.; Smits, E.C.P.; Blom, P.W.M.; Leeuw, D.M. de

    2012-01-01

    The charge injection barriers in organic field-effect transistors (OFETs) seem to be far less critical as compared to organic light-emitting diodes (OLEDs). Counter intuitively, we show that the origin is image-force lowering of the barrier due to the gate bias at the source contact, although the

  16. Charge transport in dual-gate organic field-effect transistors

    NARCIS (Netherlands)

    Brondijk, J.J.; Spijkman, M.; Torricelli, F.; Blom, P.W.M.; Leeuw, D.M. de

    2012-01-01

    The charge carrier distribution in dual-gate field-effect transistors is investigated as a function of semiconductor thickness. A good agreement with 2-dimensional numerically calculated transfer curves is obtained. For semiconductor thicknesses larger than the accumulation width, two spatially

  17. Extended-gate organic field-effect transistor for the detection of histamine in water

    Science.gov (United States)

    Minamiki, Tsukuru; Minami, Tsuyoshi; Yokoyama, Daisuke; Fukuda, Kenjiro; Kumaki, Daisuke; Tokito, Shizuo

    2015-04-01

    As part of our ongoing research program to develop health care sensors based on organic field-effect transistor (OFET) devices, we have attempted to detect histamine using an extended-gate OFET. Histamine is found in spoiled or decayed fish, and causes foodborne illness known as scombroid food poisoning. The new OFET device possesses an extended gate functionalized by carboxyalkanethiol that can interact with histamine. As a result, we have succeeded in detecting histamine in water through a shift in OFET threshold voltage. This result indicates the potential utility of the designed OFET devices in food freshness sensing.

  18. Irreversible degradation behaviors of an electrolyte-gated polyaniline (PANI) nanowire field-effect transistor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Yong; Lee, Sang-Kwon [Chonbuk National University, Jeonju (Korea, Republic of); Lim, Hyun-Eui; Choi, Gyoung-Rin [Korean Institute of Machinery and Materials, Daejeon (Korea, Republic of)

    2010-12-15

    We studied the degradation properties of a conducing polyaniline (PANI) nanowire field-effect transistor (FET) operating in a three-probe FET structure in an electrolyte solution on a SiO{sub 2}/Si substrate. We observed that the current-voltage characteristics of an electrolyte-gated PANI nanowire FET swept for 13 cycles in a cyclic potential mode exhibited clear irreversible degradation, as shown by the drain current-gate voltage curves. We propose that the degradation of the PANI nanowire FET, which indicates a conductance loss and gain in the oxidation and reduction modes, respectively, is attributable to the intensity of Coulombic repulsion in the cycle mode.

  19. A convenient method of manufacturing liquid-gated MoS2 field effect transistors

    Science.gov (United States)

    Lin, Kabin; Yuan, Zhishan; Yu, Yu; Li, Kun; Li, Zhongwu; Sha, Jingjie; Li, Tie; Chen, Yunfei

    2017-10-01

    In this paper, we present a simple and convenient method of manufacturing liquid-gated MoS2 field effect transistors (FETs). A Si3N4 chip is firstly fabricated by the semiconductor manufacturing process, then the mechanical exfoliation MoS2 is transferred onto the Si3N4 chip and is connected with the gold electrodes by depositing platinum to construct the MoS2 FETs. The liquid-gated is formed by injecting 0.1 M NaCl solution into reservoir to contact the back side of the Si3N4. Our measured results show that the contact properties between MoS2 and electrodes are in well condition and the liquid-gated MoS2 FETs have a high mobility that can reach up to 109 cm2 V‑1 s‑1.

  20. Radiation hardening of MOS devices by boron. [for stabilizing gate threshold potential of field effect device

    Science.gov (United States)

    Danchenko, V. (Inventor)

    1974-01-01

    A technique is described for radiation hardening of MOS devices and specifically for stabilizing the gate threshold potential at room temperature of a radiation subjected MOS field-effect device with a semiconductor substrate, an insulating layer of oxide on the substrate, and a gate electrode disposed on the insulating layer. The boron is introduced within a layer of the oxide of about 100 A-300 A thickness immediately adjacent the semiconductor-insulator interface. The concentration of boron in the oxide layer is preferably maintained on the order of 10 to the 18th power atoms/cu cm. The technique serves to reduce and substantially annihilate radiation induced positive gate charge accumulations.

  1. Measurement and Analysis of a Ferroelectric Field-Effect Transistor NAND Gate

    Science.gov (United States)

    Phillips, Thomas A.; MacLeond, Todd C.; Sayyah, Rana; Ho, Fat Duen

    2009-01-01

    Previous research investigated expanding the use of Ferroelectric Field-Effect Transistors (FFET) to other electronic devices beyond memory circuits. Ferroelectric based transistors possess unique characteris tics that give them interesting and useful properties in digital logic circuits. The NAND gate was chosen for investigation as it is one of the fundamental building blocks of digital electronic circuits. In t his paper, NAND gate circuits were constructed utilizing individual F FETs. N-channel FFETs with positive polarization were used for the standard CMOS NAND gate n-channel transistors and n-channel FFETs with n egative polarization were used for the standard CMOS NAND gate p-chan nel transistors. The voltage transfer curves were obtained for the NA ND gate. Comparisons were made between the actual device data and the previous modeled data. These results are compared to standard MOS logic circuits. The circuits analyzed are not intended to be fully opera tional circuits that would interface with existing logic circuits, bu t as a research tool to look into the possibility of using ferroelectric transistors in future logic circuits. Possible applications for th ese devices are presented, and their potential benefits and drawbacks are discussed.

  2. Inhomogeneous screening of gate electric field by interface states in graphene FETs

    Science.gov (United States)

    Singh, Anil Kumar; Gupta, Anjan Kumar

    2017-09-01

    The electronic states at graphene-SiO2 interface and their inhomogeneity is investigated using the back-gate-voltage dependence of local tunnel spectra acquired with a scanning tunneling microscope. The conductance spectra show two, or occasionally three, minima that evolve along the bias-voltage axis with the back gate voltage. This evolution is modeled using tip-gating and interface states. The energy dependent interface states’ density, Dit(E) , required to model the back-gate evolution of the minima, is found to have significant inhomogeneity in its energy-width. A broad Dit(E) leads to an effect similar to a reduction in the Fermi velocity while the narrow Dit(E) leads to the pinning of the Fermi energy close to the Dirac point, as observed in some places, due to enhanced screening of the gate electric field by the narrow Dit(E) . Finally, this also demonstrates STM as a tool to probe the density of interface states in various 2D Dirac materials.

  3. A compact, short-pulse laser for near-field, range-gated imaging

    Energy Technology Data Exchange (ETDEWEB)

    Zutavern, F.J.; Helgeson, W.D.; Loubriel, G.M. [Sandia National Labs., Albuquerque, NM (United States); Yates, G.J.; Gallegos, R.A.; McDonald, T.E. [Los Alamos National Lab., NM (United States)

    1996-12-31

    This paper describes a compact laser, which produces high power, wide-angle emission for a near-field, range-gated, imaging system. The optical pulses are produced by a 100 element laser diode array (LDA) which is pulsed with a GaAs, photoconductive semiconductor switch (PCSS). The LDA generates 100 ps long, gain-switched, optical pulses at 904 nm when it is driven with 3 ns, 400 A, electrical pulses from a high gain PCSS. Gain switching is facilitated with this many lasers by using a low impedance circuit to drive an array of lasers, which are connected electrically in series. The total optical energy produced per pulse is 10 microjoules corresponding to a total peak power of 100 kW. The entire laser system, including prime power (a nine volt battery), pulse charging, PCSS, and LDA, is the size of a small, hand-held flashlight. System lifetime, which is presently limited by the high gain PCSS, is an active area of research and development. Present limitations and potential improvements will be discussed. The complete range-gated imaging system is based on complementary technologies: high speed optical gating with intensified charge coupled devices (ICCD) developed at Los Alamos National Laboratory (LANL) and high gain, PCSS-driven LDAs developed at Sandia National Laboratories (SNL). The system is designed for use in highly scattering media such as turbid water or extremely dense fog or smoke. The short optical pulses from the laser and high speed gating of the ICCD are synchronized to eliminate the back-scattered light from outside the depth of the field of view (FOV) which may be as short as a few centimeters. A high speed photodiode can be used to trigger the intensifier gate and set the range-gated FOV precisely on the target. The ICCD and other aspects of the imaging system are discussed in a separate paper.

  4. Nanoscaled biological gated field effect transistors for cytogenetic analysis

    DEFF Research Database (Denmark)

    Kwasny, Dorota; Dimaki, Maria; Andersen, Karsten Brandt

    2014-01-01

    Cytogenetic analysis is the study of chromosome structure and function, and is often used in cancer diagnosis, as many chromosome abnormalities are linked to the onset of cancer. A novel label free detection method for chromosomal translocation analysis using nanoscaled field effect transistors...

  5. Development of a field test method for total suspended solids analysis.

    Science.gov (United States)

    2013-11-01

    Total suspended solids (TSS) are all particles in water that will not pass through a glass fiber filter with a pore size less : than 2 m, including sediments, algae, nutrients, and metals. TSS is an important water quality parameter because of its ...

  6. Field-emission cathode gating for rf electron guns

    OpenAIRE

    Lewellen, J. W.; J. Noonan

    2005-01-01

    We present a novel method of combining the most desirable characteristics of thermionic-cathode and photocathode rf guns, using a field-emission cathode and multiple rf frequencies. Simulations indicate that extremely low-emittance beams (on the order of 2 nm normalized emittance) at moderate beam currents (1 mA) and beam energies of ∼2  MeV can be obtained using this technique. The resulting gun design promises to be useful as a driver source for a number of applications, including high-volt...

  7. High performance top-gated multilayer WSe2 field effect transistors

    Science.gov (United States)

    Pudasaini, Pushpa Raj; Stanford, Michael G.; Oyedele, Akinola; Wong, Anthony T.; Hoffman, Anna N.; Briggs, Dayrl P.; Xiao, Kai; Mandrus, David G.; Ward, Thomas Z.; Rack, Philip D.

    2017-11-01

    In this paper, high performance top-gated WSe2 field effect transistor (FET) devices are demonstrated via a two-step remote plasma assisted ALD process. High-quality, low-leakage aluminum oxide (Al2O3) gate dielectric layers are deposited onto the WSe2 channel using a remote plasma assisted ALD process with an ultrathin (∼1 nm) titanium buffer layer. The first few nanometers (∼2 nm) of the Al2O3 dielectric film is deposited at relatively low temperature (i.e. 50 °C) and remainder of the film is deposited at 150 °C to ensure the conformal coating of Al2O3 on the WSe2 surface. Additionally, an ultra-thin titanium buffer layer is introduced at the WSe2 channel surface prior to ALD process to mitigate oxygen plasma induced doping effects. Excellent device characteristics with current on–off ratio in excess of 106 and a field effect mobility as high as 70.1 cm2 V–1 s–1 are achieved in a few-layer WSe2 FET device with a 30 nm Al2O3 top-gate dielectric. With further investigation and careful optimization, this method can play an important role for the realization of high performance top gated FETs for future optoelectronic device applications.

  8. Nonoptical Detection of Allergic Response with a Cell-Coupled Gate Field-Effect Transistor.

    Science.gov (United States)

    Yang, Haoyue; Honda, Masatoshi; Saito, Akiko; Kajisa, Taira; Yanase, Yuhki; Sakata, Toshiya

    2017-12-05

    In this study, we report the label-free and reliable detection of allergic response using a cell-coupled gate field-effect transistor (cell-based FET). Rat basophilic leukemia (RBL-2H3) cells were cultured as a signal transduction interface to induce allergic reaction on the gate oxide surface of the FET, because IgE antibodies, which bind to Fcε receptors at the RBL-2H3 cell membrane, are specifically cross-linked by allergens, resulting in the allergic response of RBL-2H3 cells. In fact, the surface potential at the FET gate decreased owing to secretions such as histamine from the IgE-bound RBL-2H3 cells, which reacted with the allergen. This is because histamine, as one of the candidate secretions, shows basicity, resulting in a change in pH around the cell/gate interface. That is, the RBL-2H3-cell-based FET used in this study was originally from an ion-sensitive FET (ISFET), whose oxide surface (Ta2O5) with hydroxyl groups is fully responsive to pH on the basis of the equilibrium reaction. The allergic response of RBL-2H3 cells on the gate was also confirmed by estimating the amount of β-hexosaminidase released together with histamine and was analyzed using the electrical properties based on an inflammatory response of secreted histamine with the vascular endothelial cell-based FET. Thus, the allergic responses were monitored in a nonoptical and real-time manner using the cell-based FETs with the cellular layers on the gate, which reproduced the in vivo system and were useful for the reliable detection of the allergic reaction.

  9. Field-emission cathode gating for rf electron guns

    Directory of Open Access Journals (Sweden)

    J. W. Lewellen

    2005-03-01

    Full Text Available We present a novel method of combining the most desirable characteristics of thermionic-cathode and photocathode rf guns, using a field-emission cathode and multiple rf frequencies. Simulations indicate that extremely low-emittance beams (on the order of 2 nm normalized emittance at moderate beam currents (1 mA and beam energies of ∼2  MeV can be obtained using this technique. The resulting gun design promises to be useful as a driver source for a number of applications, including high-voltage electron microscopy, precision electron-beam welding, and long-wavelength (THz radiation generation; we include performance calculations for the electron microscopy and precision welding applications.

  10. Field-emission cathode gating for rf electron guns

    Science.gov (United States)

    Lewellen, J. W.; Noonan, J.

    2005-03-01

    We present a novel method of combining the most desirable characteristics of thermionic-cathode and photocathode rf guns, using a field-emission cathode and multiple rf frequencies. Simulations indicate that extremely low-emittance beams (on the order of 2 nm normalized emittance) at moderate beam currents (1 mA) and beam energies of ˜2 MeV can be obtained using this technique. The resulting gun design promises to be useful as a driver source for a number of applications, including high-voltage electron microscopy, precision electron-beam welding, and long-wavelength (THz) radiation generation; we include performance calculations for the electron microscopy and precision welding applications.

  11. Fabrication of a Silicon Nanowire on a Bulk Substrate by Use of a Plasma Etching and Total Ionizing Dose Effects on a Gate-All-Around Field-Effect Transistor

    Science.gov (United States)

    Moon, Dong-Il; Han, Jin-Woo; Meyyappan, Meyya

    2016-01-01

    The gate all around transistor is investigated through experiment. The suspended silicon nanowire for the next generation is fabricated on bulk substrate by plasma etching method. The scallop pattern generated by Bosch process is utilized to form a floating silicon nanowire. By combining anisotropic and istropic silicon etch process, the shape of nanowire is accurately controlled. From the suspended nanowire, the gate all around transistor is demonstrated. As the silicon nanowire is fully surrounded by the gate, the device shows excellent electrostatic characteristics.

  12. Suspended conductive plate oscillations in the magnetic field of the conductor with alternating current

    Directory of Open Access Journals (Sweden)

    Popov Ivan

    2014-01-01

    Full Text Available The problem of cooling the conductor with an alternating high-ampere electric current is offered to be solved by using oscillations of suspended conductive plate. System basic parameters are estimated from analysing the system of differential equations describing the motions in coupled electrical-mechanical system. The parameters must satisfy the conditions of system’s resonance. Examination of equilibrium position causes a researching of the differential equation with periodic coefficients.

  13. Suspended conductive plate oscillations in the magnetic field of the conductor with alternating current

    OpenAIRE

    Popov Ivan; Lukin Alexey; Skubov Dmitry; Shtukin Lev

    2014-01-01

    The problem of cooling the conductor with an alternating high-ampere electric current is offered to be solved by using oscillations of suspended conductive plate. System basic parameters are estimated from analysing the system of differential equations describing the motions in coupled electrical-mechanical system. The parameters must satisfy the conditions of system’s resonance. Examination of equilibrium position causes a researching of the differential equation with periodic coefficients.

  14. Dielectric interface-dependent spatial charge distribution in ambipolar polymer semiconductors embedded in dual-gate field-effect transistors

    NARCIS (Netherlands)

    Lee, J.; Roelofs, W.S.C.; Janssen, R.A.J.; Gelinck, G.H.

    2016-01-01

    The spatial charge distribution in diketopyrrolopyrrole-containing ambipolar polymeric semiconductors embedded in dual-gate field-effect transistors (DGFETs) was investigated. The DGFETs have identical active channel layers but two different channel/gate interfaces, with a CYTOP™ organic dielectric

  15. Stable Low-Voltage Operation Top-Gate Organic Field-Effect Transistors on Cellulose Nanocrystal Substrates

    Science.gov (United States)

    Cheng-Yin Wang; Canek Fuentes-Hernandez; Jen-Chieh Liu; Amir Dindar; Sangmoo Choi; Jeffrey P. Youngblood; Robert J. Moon; Bernard Kippelen

    2015-01-01

    We report on the performance and the characterization of top-gate organic field-effect transistors (OFETs), comprising a bilayer gate dielectric of CYTOP/ Al2O3 and a solution-processed semiconductor layer made of a blend of TIPS-pentacene:PTAA, fabricated on recyclable cellulose nanocrystal−glycerol (CNC/glycerol...

  16. Extended Gate Field-Effect Transistor Biosensors for Point-Of-Care Testing of Uric Acid.

    Science.gov (United States)

    Guan, Weihua; Reed, Mark A

    2017-01-01

    An enzyme-free redox potential sensor using off-chip extended-gate field effect transistor (EGFET) with a ferrocenyl-alkanethiol modified gold electrode has been used to quantify uric acid concentration in human serum and urine. Hexacyanoferrate (II) and (III) ions are used as redox reagent. The potentiometric sensor measures the interface potential on the ferrocene immobilized gold electrode, which is modulated by the redox reaction between uric acid and hexacyanoferrate ions. The device shows a near Nernstian response to uric acid and is highly specific to uric acid in human serum and urine. The interference that comes from glucose, bilirubin, ascorbic acid, and hemoglobin is negligible in the normal concentration range of these interferents. The sensor also exhibits excellent long term reliability and is regenerative. This extended gate field effect transistor based sensor is promising for point-of-care detection of uric acid due to the small size, low cost, and low sample volume consumption.

  17. Optical holonomic single quantum gates with a geometric spin under a zero field

    Science.gov (United States)

    Sekiguchi, Yuhei; Niikura, Naeko; Kuroiwa, Ryota; Kano, Hiroki; Kosaka, Hideo

    2017-04-01

    The realization of fast fault-tolerant quantum gates on a single spin is the core requirement for solid-state quantum-information processing. As polarized light shows geometric interference, spin coherence is also geometrically controlled with light via the spin-orbit interaction. Here, we show that a geometric spin in a degenerate subspace of a spin-1 electronic system under a zero field in a nitrogen vacancy centre in diamond allows implementation of optical non-adiabatic holonomic quantum gates. The geometric spin under quasi-resonant light exposure undergoes a cyclic evolution in the spin-orbit space, and acquires a geometric phase or holonomy that results in rotations about an arbitrary axis by any angle defined by the light polarization and detuning. This enables universal holonomic quantum gates with a single operation. We demonstrate a complete set of Pauli quantum gates using the geometric spin preparation and readout techniques. The new scheme opens a path to holonomic quantum computers and repeaters.

  18. B-doped diamond field-effect transistor with ferroelectric vinylidene fluoride-trifluoroethylene gate insulator

    Science.gov (United States)

    Karaya, Ryota; Baba, Ikki; Mori, Yosuke; Matsumoto, Tsubasa; Nakajima, Takashi; Tokuda, Norio; Kawae, Takeshi

    2017-10-01

    A B-doped diamond field-effect transistor (FET) with a ferroelectric vinylidene fluoride-trifluoroethylene (VDF-TrFE) copolymer gate insulator was fabricated. The VDF-TrFE film deposited on the B-doped diamond showed good insulating and ferroelectric properties. Also, a Pt/VDF-TrFE/B-doped diamond layered structure showed ideal behavior as a metal-ferroelectric-semiconductor (MFS) capacitor, and the memory window width was 11 V, when the gate voltage was swept from 20 to -20 V. The fabricated MFS-type FET structure showed the typical properties of a depletion-type p-channel FET and a maximum drain current density of 0.87 mA/mm at room temperature. The drain current versus gate voltage curves of the proposed FET showed a clockwise hysteresis loop owing to the ferroelectricity of the VDF-TrFE gate insulator. In addition, we demonstrated the logic inverter with the MFS-type diamond FET coupled with a load resistor, and obtained the inversion behavior of the input signal and a maximum gain of 18.4 for the present circuit.

  19. Digital model of TiO(2 memristor for field-programmable gate array

    Directory of Open Access Journals (Sweden)

    Guangyi Wang

    2014-03-01

    Full Text Available A digital model which imitates the behaviour of a TiO(2 memristor as a new block in Alter DSP Builder is proposed in this Letter. The proposed model can be used as an independent memristor unit working with other units for designing memristor circuits based on field-programmable gate array. The accuracy of the digital model is confirmed not only by simulations, but also by hardwire experiments.

  20. Implementing a Microcontroller Watchdog with a Field-Programmable Gate Array (FPGA)

    Science.gov (United States)

    Straka, Bartholomew

    2013-01-01

    Reliability is crucial to safety. Redundancy of important system components greatly enhances reliability and hence safety. Field-Programmable Gate Arrays (FPGAs) are useful for monitoring systems and handling the logic necessary to keep them running with minimal interruption when individual components fail. A complete microcontroller watchdog with logic for failure handling can be implemented in a hardware description language (HDL.). HDL-based designs are vendor-independent and can be used on many FPGAs with low overhead.

  1. Magnetic-Induced-Piezopotential Gated MoS2Field-Effect Transistor at Room Temperature.

    Science.gov (United States)

    Liu, Yudong; Guo, Junmeng; Yu, Aifang; Zhang, Yang; Kou, Jinzong; Zhang, Ke; Wen, Rongmei; Zhang, Yan; Zhai, Junyi; Wang, Zhong Lin

    2018-01-10

    Utilizing magnetic field directly modulating/turning the charge carrier transport behavior of field-effect transistor (FET) at ambient conditions is an enormous challenge in the field of micro-nanoelectronics. Here, a new type of magnetic-induced-piezopotential gated field-effect-transistor (MIPG-FET) base on laminate composites is proposed, which consists of Terfenol-D, a ferroelectric single crystal (PMNPT), and MoS 2 flake. When applying an external magnetic field to the MIPG-FET, the piezopotential of PMNPT triggered by magnetostriction of the Terfenol-D can serve as the gate voltage to effectively modulate/control the carrier transport process and the corresponding drain current at room temperature. Considering the two polarization states of PMNPT, the drain current is diminished from 9.56 to 2.9 µA in the P up state under a magnetic field of 33 mT, and increases from 1.41 to 4.93 µA in the P down state under a magnetic field of 42 mT and at a drain voltage of 3 V. The current on/off ratios in these states are 330% and 432%, respectively. This work provides a novel noncontact coupling method among magnetism, piezoelectricity, and semiconductor properties, which may have extremely important applications in magnetic sensors, memory and logic devices, micro-electromechanical systems, and human-machine interfacing. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Fabrication and characterization of a charge-biased CMOS-MEMS resonant gate field effect transistor

    Science.gov (United States)

    Chin, C. H.; Li, C. S.; Li, M. H.; Wang, Y. L.; Li, S. S.

    2014-09-01

    A high-frequency charge-biased CMOS-MEMS resonant gate field effect transistor (RGFET) composed of a metal-oxide composite resonant-gate structure and an FET transducer has been demonstrated utilizing the TSMC 0.35 μm CMOS technology with Q > 1700 and a signal-to-feedthrough ratio greater than 35 dB under a direct two-port measurement configuration. As compared to the conventional capacitive-type MEMS resonators, the proposed CMOS-MEMS RGFET features an inherent transconductance gain (gm) offered by the FET transduction capable of enhancing the motional signal of the resonator and relaxing the impedance mismatch issue to its succeeding electronics or 50 Ω-based test facilities. In this work, we design a clamped-clamped beam resonant-gate structure right above a floating gate FET transducer as a high-Q building block through a maskless post-CMOS process to combine merits from the large capacitive transduction areas of the large-width beam resonator and the high gain of the underneath FET. An analytical model is also provided to simulate the behavior of the charge-biased RGFET; the theoretical prediction is in good agreement with the experimental results. Thanks to the deep-submicrometer gap spacing enabled by the post-CMOS polysilicon release process, the proposed resonator under a purely capacitive transduction already attains motional impedance less than 10 kΩ, a record-low value among CMOS-MEMS capacitive resonators. To go one step further, the motional signal of the proposed RGFET is greatly enhanced through the FET transduction. Such a strong transmission and a sharp phase transition across 0° pave a way for future RGFET-type oscillators in RF and sensor applications. A time-elapsed characterization of the charge leakage rate for the floating gate is also carried out.

  3. Interface trap of p-type gate integrated AlGaN/GaN heterostructure field effect transistors

    Science.gov (United States)

    Kim, Kyu Sang

    2017-09-01

    In this work, the impact of trap states at the p-(Al)GaN/AlGaN interface has been investigated for the normally-off mode p-(Al)GaN/AlGaN/GaN heterostructure field-effect transistors (HFETs) by means of frequency dependent conductance. From the current-voltage (I-V) measurement, it was found that the p-AlGaN gate integrated device has higher drain current and lower gate leakage current compared to the p-GaN gate integrated device. We obtained the interface trap density and the characteristic time constant for the p-type gate integrated HFETs under the forward gate voltage of up to 6 V. As a result, the interface trap density (characteristic time constant) of the p-GaN gate device was lower (longer) than that of the p-AlGaN. Furthermore, it was analyzed that the trap state energy level of the p-GaN gate device was located at the shallow level relative to the p-AlGaN gate device, which accounts for different gate leakage current of each devices.

  4. Modeling of a quantized current and gate field-effect in gated three-terminal Cu2-αS electrochemical memristors

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2015-02-01

    Full Text Available Memristors exhibit very sharp off-to-on transitions with a large on/off resistance ratio. These remarkable characteristics coupled with their long retention time and very simple device geometry make them nearly ideal for three-terminal devices where the gate voltage can change their on/off voltages and/or simply turn them off, eliminating the need for bipolar operations. In this paper, we propose a cation migration-based computational model to explain the quantized current conduction and the gate field-effect in Cu2-αS memristors. Having tree-shaped conductive filaments inside a memristor is the reason for the quantized current conduction effect. Applying a gate voltage causes a deformation of the conductive filaments and thus controls the SET and the RESET process of the device.

  5. A novel Tunneling Graphene Nano Ribbon Field Effect Transistor with dual material gate: Numerical studies

    Science.gov (United States)

    Ghoreishi, Seyed Saleh; Saghafi, Kamyar; Yousefi, Reza; Moravvej-farshi, Mohammad Kazem

    2016-09-01

    In this work, we present Dual Material Gate Tunneling Graphene Nano-Ribbon Field Effect Transistors (DMG-T-GNRFET) mainly to suppress the am-bipolar current with assumption that sub-threshold swing which is one of the important characteristics of tunneling transistors must not be degraded. In the proposed structure, dual material gates with different work functions are used. Our investigations are based on numerical simulations which self-consistently solves the 2D Poisson based on an atomistic mode-space approach and Schrodinger equations, within the Non-Equilibrium Green's (NEGF). The proposed device shows lower off-current and on-off ratio becomes 5order of magnitude greater than the conventional device. Also two different short channel effects: Drain Induced Barrier Shortening (DIBS) and hot-electron effect are improved in the proposed device compare to the main structure.

  6. Physiologically gated microbeam radiation using a field emission x-ray source array

    Energy Technology Data Exchange (ETDEWEB)

    Chtcheprov, Pavel, E-mail: PavelC@unc.edu, E-mail: zhou@email.unc.edu [Department of Biomedical Engineering, University of North Carolina, 152 MacNider Hall, Campus Box 7575, Chapel Hill, North Carolina 27599 (United States); Burk, Laurel; Inscoe, Christina; Ger, Rachel; Hadsell, Michael; Lu, Jianping [Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 (United States); Yuan, Hong [Department of Radiology, University of North Carolina, 2006 Old Clinic, CB #7510, Chapel Hill, North Carolina 27599 (United States); Zhang, Lei [Department of Applied Physical Sciences, University of North Carolina, Chapman Hall, CB#3216, Chapel Hill, North Carolina 27599 (United States); Chang, Sha [Department of Radiation Oncology, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 (United States); Zhou, Otto, E-mail: PavelC@unc.edu, E-mail: zhou@email.unc.edu [Department of Physics and Astronomy, University of North Carolina, Phillips Hall, CB #3255, 120 East Cameron Avenue, Chapel Hill, North Carolina 27599 and UNC Lineberger Comprehensive Cancer Center, University of North Carolina, 101 Manning Drive, Chapel Hill, North Carolina 27514 (United States)

    2014-08-15

    Purpose: Microbeam radiation therapy (MRT) uses narrow planes of high dose radiation beams to treat cancerous tumors. This experimental therapy method based on synchrotron radiation has been shown to spare normal tissue at up to 1000 Gy of peak entrance dose while still being effective in tumor eradication and extending the lifetime of tumor-bearing small animal models. Motion during treatment can lead to significant movement of microbeam positions resulting in broader beam width and lower peak to valley dose ratio (PVDR), which reduces the effectiveness of MRT. Recently, the authors have demonstrated the feasibility of generating microbeam radiation for small animal treatment using a carbon nanotube (CNT) x-ray source array. The purpose of this study is to incorporate physiological gating to the CNT microbeam irradiator to minimize motion-induced microbeam blurring. Methods: The CNT field emission x-ray source array with a narrow line focal track was operated at 160 kVp. The x-ray radiation was collimated to a single 280 μm wide microbeam at entrance. The microbeam beam pattern was recorded using EBT2 Gafchromic{sup ©} films. For the feasibility study, a strip of EBT2 film was attached to an oscillating mechanical phantom mimicking mouse chest respiratory motion. The servo arm was put against a pressure sensor to monitor the motion. The film was irradiated with three microbeams under gated and nongated conditions and the full width at half maximums and PVDRs were compared. An in vivo study was also performed with adult male athymic mice. The liver was chosen as the target organ for proof of concept due to its large motion during respiration compared to other organs. The mouse was immobilized in a specialized mouse bed and anesthetized using isoflurane. A pressure sensor was attached to a mouse's chest to monitor its respiration. The output signal triggered the electron extraction voltage of the field emission source such that x-ray was generated only

  7. Role of deposition and annealing of the top gate dielectric in a-IGZO TFT-based dual-gate ion-sensitive field-effect transistors

    Science.gov (United States)

    Kumar, Narendra; Sutradhar, Moitri; Kumar, Jitendra; Panda, Siddhartha

    2017-03-01

    The deposition of the top gate dielectric in thin film transistor (TFT)-based dual-gate ion-sensitive field-effect transistors (DG ISFETs) is critical, and expected not to affect the bottom gate TFT characteristics, while providing a higher pH sensitive surface and efficient capacitive coupling between the gates. Amorphous Ta2O5, in addition to having good sensing properties, possesses a high dielectric constant of ˜25 making it well suited as the top gate dielectric in a DG ISFET by providing higher capacitive coupling (ratio of C top/C bottom) leading to higher amplification. To avoid damage of the a-IGZO channel reported to be caused by plasma exposure, deposition of Ta2O5 by e-beam evaporation followed by annealing was investigated in this work to obtain sensitivity over the Nernst limit. The deteriorated bottom gate TFT characteristics, indicated by an increase in the channel conductance, confirmed that plasma exposure is not the sole contributor to the changes. Oxygen vacancies at the Ta2O5/a-IGZO interface, which emerged during processing, increased the channel conductivity, became filled by optimum annealing in oxygen at 400 °C for 1 h, which was confirmed by an x-ray photoelectron spectroscopy depth profiling analysis. The obtained pH sensitivity of the TFT-based DG ISFET was 402 mV pH-1, which is about 6.8 times the Nernst limit (59 mV pH-1). The concept of capacitive coupling was also demonstrated by simulating an a-IGZO-based DG TFT structure. Here, the exposure of the top gate dielectric to the electrolyte without applying any top gate bias led to changes in the measured threshold voltage of the bottom gate TFT, and this obviated the requirement of a reference electrode needed in conventional ISFETs and other reported DG ISFETs. These devices, with high sensitivities and requiring low volumes (˜2 μl) of analyte solution, could be potential candidates for utilization as chemical sensors and biosensors.

  8. Electron Transport in Graphene Nanoribbon Field-Effect Transistor under Bias and Gate Voltages: Isochemical Potential Approach.

    Science.gov (United States)

    Yun, Jeonghun; Lee, Geunsik; Kim, Kwang S

    2016-07-07

    Zigzag graphene nanoribbon (zGNR) of narrow width has a moderate energy gap in its antiferromagnetic ground state. So far, first-principles electron transport calculations have been performed using nonequilibrium Green function (NEGF) method combined with density functional theory (DFT). However, the commonly practiced bottom-gate control has not been studied computationally due to the need to simulate an electron reservoir that fixes the chemical potential of electrons in the zGNR and electrodes. Here, we present the isochemical potential scheme to describe the top/back-gate effect using external potential. Then, we examine the change in electronic state under the modulation of chemical potential and the subsequent electron transport phenomena in zGNR transistor under substantial top-/back-gate and bias voltages. The gate potential can activate the device states resulting in a boosted current. This gate-controlled current-boosting could be utilized for designing novel zGNR field effect transistors (FETs).

  9. A High-Performance Top-Gated Graphene Field-Effect Transistor with Excellent Flexibility Enabled by an iCVD Copolymer Gate Dielectric.

    Science.gov (United States)

    Oh, Joong Gun; Pak, Kwanyong; Kim, Choong Sun; Bong, Jae Hoon; Hwang, Wan Sik; Im, Sung Gap; Cho, Byung Jin

    2018-03-01

    A high-performance top-gated graphene field-effect transistor (FET) with excellent mechanical flexibility is demonstrated by implementing a surface-energy-engineered copolymer gate dielectric via a solvent-free process called initiated chemical vapor deposition. The ultrathin, flexible copolymer dielectric is synthesized from two monomers composed of 1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane and 1-vinylimidazole (VIDZ). The copolymer dielectric enables the graphene device to exhibit excellent dielectric performance and substantially enhanced mechanical flexibility. The p-doping level of the graphene can be tuned by varying the polar VIDZ fraction in the copolymer dielectric, and the Dirac voltage (V Dirac ) of the graphene FET can thus be systematically controlled. In particular, the V Dirac approaches neutrality with higher VIDZ concentrations in the copolymer dielectric, which minimizes the carrier scattering and thereby improves the charge transport of the graphene device. As a result, the graphene FET with 20 nm thick copolymer dielectrics exhibits field-effect hole and electron mobility values of over 7200 and 3800 cm 2 V -1 s -1 , respectively, at room temperature. These electrical characteristics remain unchanged even at the 1 mm bending radius, corresponding to a tensile strain of 1.28%. The formed gate stack with the copolymer gate dielectric is further investigated for high-frequency flexible device applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Touch sensors based on planar liquid crystal-gated-organic field-effect transistors

    Directory of Open Access Journals (Sweden)

    Jooyeok Seo

    2014-09-01

    Full Text Available We report a tactile touch sensor based on a planar liquid crystal-gated-organic field-effect transistor (LC-g-OFET structure. The LC-g-OFET touch sensors were fabricated by forming the 10 μm thick LC layer (4-cyano-4′-pentylbiphenyl - 5CB on top of the 50 nm thick channel layer (poly(3-hexylthiophene - P3HT that is coated on the in-plane aligned drain/source/gate electrodes (indium-tin oxide - ITO. As an external physical stimulation to examine the tactile touch performance, a weak nitrogen flow (83.3 μl/s was employed to stimulate the LC layer of the touch device. The LC-g-OFET device exhibited p-type transistor characteristics with a hole mobility of 1.5 cm2/Vs, but no sensing current by the nitrogen flow touch was measured at sufficiently high drain (VD and gate (VG voltages. However, a clear sensing current signal was detected at lower voltages, which was quite sensitive to the combination of VD and VG. The best voltage combination was VD = −0.2 V and VG = −1 V for the highest ratio of signal currents to base currents (i.e., signal-to-noise ratio. The change in the LC alignment upon the nitrogen flow touch was assigned as the mechanism for the present LC-g-OFET touch sensors.

  11. Dramatic switching behavior in suspended MoS2 field-effect transistors

    Science.gov (United States)

    Chen, Huawei; Li, Jingyu; Chen, Xiaozhang; Zhang, David; Zhou, Peng

    2018-02-01

    When integrating MoS2 flakes into scaling-down transistors, the short-channel effect, which is severe in silicon technology below 5-nanometer, can be avoided effectively. MoS2 transistors not only exhibit a high on/off ratio but also demonstrate a rapid switching speed. According to the theoretical calculation, the thermionic limit subthreshold slope (SS) of the ideal device could reach 60 mV/dec. However, due to the confinement of defects from substrates or contamination during the process, the SS deteriorates to more than 300 mV/dec, causing serious power consumption. In this work, we optimize the SS through structure design of MoS2 transistors. The suspended transistors exhibit a high on/off ratio of 107 and a minimum SS of 63 mV/dec with an ultralow standby power at room temperature. This study demonstrates the promising potential of structure design for electronic devices with ultralow-power switching behaviors.

  12. High-resolution full-field spatial coherence gated optical tomography using monochromatic light source

    Science.gov (United States)

    Srivastava, Vishal; Nandy, Sreyankar; Singh Mehta, Dalip

    2013-09-01

    We demonstrate dispersion free, high-resolution full-field spatial coherence gated optical tomography using spatially incoherent monochromatic light source. Spatial coherence properties of light source were synthesized by means of combining a static diffuser and vibrating multi mode fiber bundle. Due to low spatial coherence of light source, the axial resolution of the system was achieved similar to that of conventional optical coherence tomography which utilizes low temporal coherence. Experimental results of fringe visibility versus optical path difference are presented for varying numerical apertures objective lenses. High resolution optically sectioned images of multilayer onion skin, and red blood cells are presented.

  13. Rapid Prototyping of Field Programmable Gate Array-Based Discrete Cosine Transform Approximations

    Directory of Open Access Journals (Sweden)

    Trevor W. Fox

    2003-05-01

    Full Text Available A method for the rapid design of field programmable gate array (FPGA-based discrete cosine transform (DCT approximations is presented that can be used to control the coding gain, mean square error (MSE, quantization noise, hardware cost, and power consumption by optimizing the coefficient values and datapath wordlengths. Previous DCT design methods can only control the quality of the DCT approximation and estimates of the hardware cost by optimizing the coefficient values. It is shown that it is possible to rapidly prototype FPGA-based DCT approximations with near optimal coding gains that satisfy the MSE, hardware cost, quantization noise, and power consumption specifications.

  14. Development of self-aligned gated porous silicon microtip field emission arrays for vacuum microelectronic applications

    Science.gov (United States)

    Jessing, Jeffrey Richard

    Solid state microelectronics is the dominate technology in the present day electronics industry. However, as the physical dimensions decrease, it is becoming apparent that solid state devices have inherent performance limitations, such as finite saturation drift velocity, high temperature degradation, and failure in extreme radiation environments. To address these problems a relatively new technology, called vacuum microelectronics, has emerged. Vacuum microelectronics encompasses the fabrication, characterization, and application of various devices whose operation is based on vacuum ballistic transport of field emitted electrons from microminiature electrodes. The field of vacuum microelectronics has advanced at a rapid rate over the past decade; however, there remain key issues to be addressed prior to any widespread commercialization of this technology. Field emission arrays (FEAs) must operate at low voltages and generate high current densities with uniform, long-lifetime operation. The use of porous silicon cathodes in vacuum microelectronic applications is a promising alternative to existing silicon and metal field emitters. Surface modification of bulk crystalline silicon by electrochemical anodization in a concentrated hydrofluoric acid (HF) solution has been shown to produce large submicroscopic field enhancement and large emission area. The primary focus of this research was the development of novel gated FEAs based on porous silicon microtip cathodes. Device design consisted of both experimental and theoretical efforts. Employing semiconductor process technology, the successful fabrication of an operational self-aligned gated porous silicon microtip FEA was demonstrated. Small arrays exhibited Fowler-Nordheim characteristics over several decades of anode current. A peak stable current of approximately 60 to 70 nA per tip was obtained at less than 125 V. A correlation of anodization conditions with emission properties has been found, and a simple emission

  15. Gate field plate IGBT with trench accumulation layer for extreme injection enhancement

    Science.gov (United States)

    Xu, Xiaorui; Chen, Wanjun; Liu, Chao; Chen, Nan; Tao, Hong; Shi, Yijun; Ma, Yinchang; Zhou, Qi; Zhang, Bo

    2017-04-01

    A gate field plate IGBT (GFP-IGBT) with extreme injection enhancement is proposed and verified using TCAD simulations. The GFP-IGBT features a gate field plate (GFP) inserted into n-drift region directly and a tiny P-base region separated from the GFP. In the ON-state, the accumulation layer is formed near to not only the bottom but also the side of the trench, which enhances electron injection efficiency. And the tiny P-base region reduces the holes extracted by reverse-biased P-base/N-drift junction. Both the GFP and tiny P-base contribute to achieving extreme injection enhancement, leading to a low forward voltage drop. In the OFF-state, due to the low stored charges in N-buffer layer, GFP-IGBT shows a short current fall time, leading to a decrease of turn-off loss. The simulation results show that, compared with the conventional IGBT, the GFP-IGBT offers a forward voltage drop reduction of 25% or current fall time reduction of 89% (i.e. turn-off loss reduction of 53%), resulting in low power loss. The excellent device performance, coupled with a commercial IGBT-compatible fabrication process, makes the proposed GFP-IGBT a promising candidate for power switching applications.

  16. An analytical modeling approach for a gate all around (GAA) tunnel field effect transistor (TFET)

    Science.gov (United States)

    Narang, Rakhi; Saxena, Manoj; Gupta, R. S.; Gupta, Mridula

    2012-10-01

    An analytical model for a gate all around (GAA) Tunnel Field Effect Transistor (TFET) having circular and square cross section geometry has been proposed in this work describing the important device electrostatic parameters i.e. Surface Potential, Electric Field and Energy Band profile. Further, the model is extended for both a p-i-n and p-n-p-n architecture keeping in view the advantages offered by a p-n-p-n architecture (also known as tunnel source or halo doped TFET) over a p-i-n based TFET. The results obtained from the model have been validated with results obtained through Silvaco ATLAS 3D device simulation software.

  17. Perspective analysis of tri gate germanium tunneling field-effect transistor with dopant segregation region at source/drain

    Science.gov (United States)

    Liu, Liang-kui; Shi, Cheng; Zhang, Yi-bo; Sun, Lei

    2017-04-01

    A tri gate Ge-based tunneling field-effect transistor (TFET) has been numerically studied with technology computer aided design (TCAD) tools. Dopant segregated Schottky source/drain is applied to the device structure design (DS-TFET). The characteristics of the DS-TFET are compared and analyzed comprehensively. It is found that the performance of n-channel tri gate DS-TFET with a positive bias is insensitive to the dopant concentration and barrier height at n-type drain, and that the dopant concentration and barrier height at a p-type source considerably affect the device performance. The domination of electron current in the entire BTBT current of this device accounts for this phenomenon and the tri-gate DS-TFET is proved to have a higher performance than its dual-gate counterpart.

  18. A Label-Free Immunosensor for IgG Based on an Extended-Gate Type Organic Field Effect Transistor

    Directory of Open Access Journals (Sweden)

    Tsukuru Minamiki

    2014-09-01

    Full Text Available A novel biosensor for immunoglobulin G (IgG detection based on an extended-gate type organic field effect transistor (OFET has been developed that possesses an anti-IgG antibody on its extended-gate electrode and can be operated below 3 V. The titration results from the target IgG in the presence of a bovine serum albumin interferent, clearly exhibiting a negative shift in the OFET transfer curve with increasing IgG concentration. This is presumed to be due an interaction between target IgG and the immobilized anti-IgG antibody on the extended-gate electrode. As a result, a linear range from 0 to 10 µg/mL was achieved with a relatively low detection limit of 0.62 µg/mL (=4 nM. We believe that these results open up opportunities for applying extended-gate-type OFETs to immunosensing.

  19. A Label-Free Immunosensor for IgG Based on an Extended-Gate Type Organic Field Effect Transistor

    Science.gov (United States)

    Minamiki, Tsukuru; Minami, Tsuyoshi; Kurita, Ryoji; Niwa, Osamu; Wakida, Shin-ichi; Fukuda, Kenjiro; Kumaki, Daisuke; Tokito, Shizuo

    2014-01-01

    A novel biosensor for immunoglobulin G (IgG) detection based on an extended-gate type organic field effect transistor (OFET) has been developed that possesses an anti-IgG antibody on its extended-gate electrode and can be operated below 3 V. The titration results from the target IgG in the presence of a bovine serum albumin interferent, clearly exhibiting a negative shift in the OFET transfer curve with increasing IgG concentration. This is presumed to be due an interaction between target IgG and the immobilized anti-IgG antibody on the extended-gate electrode. As a result, a linear range from 0 to 10 µg/mL was achieved with a relatively low detection limit of 0.62 µg/mL (=4 nM). We believe that these results open up opportunities for applying extended-gate-type OFETs to immunosensing. PMID:28788216

  20. Beyond the Nernst-limit with dual-gate ZnO ion-sensitive field-effect transistors

    NARCIS (Netherlands)

    Spijkman, M.; Smits, E. C. P.; Cillessen, J. F. M.; Biscarini, F.; Blom, P. W. M.; de Leeuw, D. M.

    2011-01-01

    The sensitivity of conventional ion-sensitive field-effect transistors (ISFETs) is limited to 59 mV/pH, which is the maximum detectable change in electrochemical potential according to the Nernst equation. Here we demonstrate a transducer based on a ZnO dual-gate field-effect transistor that

  1. Influences of suspended particles on the runoff of pesticides from an agricultural field at Askim, SE-Norway.

    Science.gov (United States)

    Wu, Q; Riise, G; Lundekvam, H; Mulder, J; Haugen, L E

    2004-01-01

    Field and laboratory experiments were conducted to study the loss of particles from agricultural fields, and the role of suspended particles in carrying pesticides in surface runoff and drainage water. Propiconazole, a widely used fungicide was applied to experimental fields located at Askim, SE-Norway. Samples from surface runoff and drainage water were collected and analyzed for sediment mass, pesticides, particulate and dissolved organic carbon through a whole year. The surface soil and the runoff material were characterized by its particle size distribution, organic carbon content in size fractions and its ability to bind propiconazole. The results show that (1) particle runoff mostly occurred during the rainfall event shortly after harrowing in autumn. The highest particle concentration observed in the surface runoff water was 4600 mg l(-1), and in the drainage water 1130 mg l(-1); (2) the erosion of surface soil is size selective. The runoff sediment contained finer particle/aggregates rich in organic matter compared to its original surface soil; (3) the distribution coefficient (Kd) of propiconazole was significantly higher in the runoff sediment than in the parent soil. According to our calculation, particle-bound propiconazole can represent up to 23% of the total amount of propiconazole in a water sample with a sediment concentration of 7600 mg l(-1), which will significantly influence the transport behavior of the pesticide.

  2. Electric field control of a fluid transfer between freely suspended and sessile droplets

    Science.gov (United States)

    Choi, Suhwan; Saveliev, Alexei

    2015-11-01

    This works explore direct fluid transfer between microdroplets using liquid bridges stabilized by ac electric field. Experiments are performed with freely and sessile microdroplets of pure glycerol and water with dye. The droplets are placed along electric field directions in a cell with parallel plate electrodes filled with silicone oil. The electrical conductivity of droplets is changed from 1 to 200 μS/cm by adding dye solutions. Liquid bridges interconnecting two microdroplets can be created using an alternating electric field from 0.3 to 0.7 kV/mm with a frequency of 10.3 kHz. For such bridging fluid can be transferred through the liquid bridge from one droplet to another due to the pressure difference. The process is recorded using a CCD camera. The fluid flowrates in the range from ~ 100 to 10 nL/s are recorded with different electric fields and liquid conductivity. We propose that the manipulation of the liquid bridge will be the method in which small fluid volumes are dispensed.

  3. Increasing the noise margin in organic circuits using dual gate field-effect transistor

    NARCIS (Netherlands)

    Spijkman, M; Smits, E.C.P.; Blom, P.W.M.; Leeuw, D.M. de; Bon Saint Côme, Y.; Setayesh, S.; Cantatore, E.

    2008-01-01

    Complex digital circuits reliably work when the noise margin of the logic gates is sufficiently high. For p-type only inverters, the noise margin is typically about 1 V. To increase the noise margin, we fabricated inverters with dual gate transistors. The top gate is advantageously used to

  4. Increasing the noise margin in organic circuits using dual gate field-effect transistors

    NARCIS (Netherlands)

    Spijkman, M.; Smits, E. C. P.; Blom, P. W. M.; de Leeuw, D. M.; Saint Come, Y. Bon; Setayesh, S.; Cantatore, E.; Bon Saint Côme, Y.

    2008-01-01

    Complex digital circuits reliably work when the noise margin of the logic gates is sufficiently high. For p-type only inverters, the noise margin is typically about 1 V. To increase the noise margin, we fabricated inverters with dual gate transistors. The top gate is advantageously used to

  5. Strain and deformations engineered germanene bilayer double gate-field effect transistor by first principles

    Science.gov (United States)

    Meher Abhinav, E.; Chandrasekaran, Gopalakrishnan; Kasmir Raja, S. V.

    2017-10-01

    Germanene, silicene, stanene, phosphorene and graphene are some of single atomic materials with novel properties. In this paper, we explored bilayer germanene-based Double Gate-Field Effect Transistor (DG-FET) with various strains and deformations using Density Functional Theory (DFT) and Green's approach by first-principle calculations. The DG-FET of 1.6 nm width, 6 nm channel length (Lch) and HfO2 as gate dielectric has been modeled. For intrinsic deformation of germanene bilayer, we have enforced minute mechanical deformation of wrap and twist (5°) and ripple (0.5 Å) on germanene bilayer channel material. By using NEGF formalism, I-V Characteristics of various strains and deformation tailored DG-FET was calculated. Our results show that rough edge and single vacancy (5-9) in bilayer germanene diminishes the current around 47% and 58% respectively as compared with pristine bilayer germanene. In case of strain tailored bilayer DG-FET, multiple NDR regions were observed which can be utilized in building stable multiple logic states in digital circuits and high frequency oscillators using negative resistive techniques.

  6. Transparent field-effect transistors based on AlN-gate dielectric and IGZO-channel semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Besleaga, C.; Stan, G.E.; Pintilie, I. [National Institute of Materials Physics, 405A Atomistilor, 077125 Magurele-Ilfov (Romania); Barquinha, P.; Fortunato, E. [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, and CEMOP-UNINOVA, 2829-516 Caparica (Portugal); Martins, R., E-mail: rm@uninova.pt [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, and CEMOP-UNINOVA, 2829-516 Caparica (Portugal)

    2016-08-30

    Highlights: • TFTs based on IGZO channel semiconductor and AlN gate dielectric were fabricated. • AlN films – a viable and cheap gate dielectric alternative for transparent TFTs. • Influence of gate dielectric layer thickness on TFTs electrical characteristics. • No degradation of AlN gate dielectric was observed during devices stress testing. - Abstract: The degradation of thin-film transistors (TFTs) caused by the self-heating effect constitutes a problem to be solved for the next generation of displays. Aluminum nitride (AlN) is a viable alternative for gate dielectric of TFTs due to its good thermal conductivity, matching coefficient of thermal expansion to indium–gallium–zinc-oxide, and excellent stability at high temperatures. Here, AlN thin films of different thicknesses were fabricated by a low temperature reactive radio-frequency magnetron sputtering process, using a low cost, metallic Al target. Their electrical properties have been thoroughly assessed. Furthermore, the 200 nm and 500 nm thick AlN layers have been integrated as gate-dielectric in transparent TFTs with indium–gallium–zinc-oxide as channel semiconductor. Our study emphasizes the potential of AlN thin films for transparent electronics, whilst the functionality of the fabricated field-effect transistors is explored and discussed.

  7. Dual Gate Black Phosphorus Field Effect Transistors on Glass for NOR Logic and Organic Light Emitting Diode Switching.

    Science.gov (United States)

    Kim, Jin Sung; Jeon, Pyo Jin; Lee, Junyeong; Choi, Kyunghee; Lee, Hee Sung; Cho, Youngsuk; Lee, Young Tack; Hwang, Do Kyung; Im, Seongil

    2015-09-09

    We have fabricated dual gate field effect transistors (FETs) with 12 nm-thin black phosphorus (BP) channel on glass substrate, where our BP FETs have a patterned-gate architecture with 30 nm-thick Al2O3 dielectrics on top and bottom of a BP channel. Top gate dielectric has simultaneously been used as device encapsulation layer, controlling the threshold voltage of FETs as well when FETs mainly operate under bottom gate bias. Bottom, top, and dual gate-controlling mobilities were estimated to be 277, 92, and 213 cm(2)/V s, respectively. Maximum ON-current was measured to be ∼5 μA at a drain voltage of -0.1 V but to be as high as ∼50 μA at -1 V, while ON/OFF current ratio appeared to be 3.6 × 10(3) V. As a result, our dual gate BP FETs demonstrate organic light emitting diode (OLED) switching for green and blue OLEDs, also demonstrating NOR logic functions by separately using top- and bottom-input.

  8. Nine-channel mid-power bipolar pulse generator based on a field programmable gate array

    Energy Technology Data Exchange (ETDEWEB)

    Haylock, Ben, E-mail: benjamin.haylock2@griffithuni.edu.au; Lenzini, Francesco; Kasture, Sachin; Fisher, Paul; Lobino, Mirko [Centre for Quantum Dynamics, Griffith University, Brisbane (Australia); Queensland Micro and Nanotechnology Centre, Griffith University, Brisbane (Australia); Streed, Erik W. [Centre for Quantum Dynamics, Griffith University, Brisbane (Australia); Institute for Glycomics, Griffith University, Gold Coast (Australia)

    2016-05-15

    Many channel arbitrary pulse sequence generation is required for the electro-optic reconfiguration of optical waveguide networks in Lithium Niobate. Here we describe a scalable solution to the requirement for mid-power bipolar parallel outputs, based on pulse patterns generated by an externally clocked field programmable gate array. Positive and negative pulses can be generated at repetition rates up to 80 MHz with pulse width adjustable in increments of 1.6 ns across nine independent outputs. Each channel can provide 1.5 W of RF power and can be synchronised with the operation of other components in an optical network such as light sources and detectors through an external clock with adjustable delay.

  9. Total Ionizing Dose Response of Multiple-Gate Nanowire Field Effect Transistors

    Science.gov (United States)

    Gaillardin, M.; Marcandella, C.; Martinez, M.; Duhamel, O.; Lagutere, T.; Paillet, P.; Raine, M.; Richard, N.; Andrieu, F.; Barraud, S.; Vinet, M.

    2017-08-01

    This paper investigates the total ionizing dose (TID) response of nanoscaled field-effect transistors (FET) made of silicon multiple-gate nanowire (NW). The NWFET architecture relies on its remarkable electrostatic properties to push “silicon”-based technologies much deeper into device scaling than present FinFETs. However, as commonly observed when a new device or technology concept is proposed, such as shallow trench isolation and silicon-on-insulator or FinFET, TID effects reveal unexpected behaviors that can permanently modify pristine device electrical characteristics. This is why this paper discusses the impact of several parameters including the NWFET design and the transistor's type to get thorough insights into the NWFET TID behavior.

  10. Design and Implementation of Video Shot Detection on Field Programmable Gate Arrays

    Directory of Open Access Journals (Sweden)

    Jharna Majumdar

    2012-09-01

    Full Text Available Video has become an interactive medium of communication in everyday life. The sheer volume of video makes it extremely difficult to browse through and find the required data. Hence extraction of key frames from the video which represents the abstract of the entire video becomes necessary. The aim of the video shot detection is to find the position of the shot boundaries, so that key frames can be selected from each shot for subsequent processing such as video summarization, indexing etc. For most of the surveillance applications like video summery, face recognition etc., the hardware (real time implementation of these algorithms becomes necessary. Here in this paper we present the architecture for simultaneous accessing of consecutive frames, which are then used for the implementation of various Video Shot Detection algorithms. We also present the real time implementation of three video shot detection algorithms using the above mentioned architecture on FPGA (Field Programmable Gate Arrays.

  11. Field Programmable Gate Array for Implementation of Redundant Advanced Digital Feedback Control

    Science.gov (United States)

    King, K. D.

    2003-01-01

    The goal of this effort was to develop a digital motor controller using field programmable gate arrays (FPGAs). This is a more rugged approach than a conventional microprocessor digital controller. FPGAs typically have higher radiation (rad) tolerance than both the microprocessor and memory required for a conventional digital controller. Furthermore, FPGAs can typically operate at higher speeds. (While speed is usually not an issue for motor controllers, it can be for other system controllers.) Other than motor power, only a 3.3-V digital power supply was used in the controller; no analog bias supplies were used. Since most of the circuit was implemented in the FPGA, no additional parts were needed other than the power transistors to drive the motor. The benefits that FPGAs provide over conventional designs-lower power and fewer parts-allow for smaller packaging and reduced weight and cost.

  12. Numerical Study on Deformation and Interior Flow of a Droplet Suspended in Viscous Liquid under Steady Electric Fields

    Directory of Open Access Journals (Sweden)

    Zhentao Wang

    2014-07-01

    Full Text Available A model based on the volume of fluid (VOF method and leaky dielectric theory is established to predict the deformation and internal flow of the droplet suspended in another vicious fluid under the influence of the electric field. Through coupling with hydrodynamics and electrostatics, the rate of deformation and internal flow of the single droplet are simulated and obtained under the different operating parameters. The calculated results show that the direction of deformation and internal flow depends on the physical properties of fluids. The numerical results are compared with Taylor's theory and experimental results by Torza et al. When the rate of deformation is small, the numerical results are consistent with theory and experimental results, and when the rate is large the numerical results are consistent with experimental results but are different from Taylor's theory. In addition, fluid viscosity hardly affects the deformation rate and mainly dominates the deformation velocity. For high viscosity droplet spends more time to attain the steady state. The conductivity ratio and permittivity ratio of two different liquids affect the direction of deformation. When fluid electric properties change, the charge distribution at the interface is various, which leads to the droplet different deformation shapes.

  13. Field programmable gate array based reconfigurable scanning probe/optical microscope.

    Science.gov (United States)

    Nowak, Derek B; Lawrence, A J; Dzegede, Zechariah K; Hiester, Justin C; Kim, Cliff; Sánchez, Erik J

    2011-10-01

    The increasing popularity of nanometrology and nanospectroscopy has pushed researchers to develop complex new analytical systems. This paper describes the development of a platform on which to build a microscopy tool that will allow for flexibility of customization to suit research needs. The novelty of the described system lies in its versatility of capabilities. So far, one version of this microscope has allowed for successful near-field and far-field fluorescence imaging with single molecule detection sensitivity. This system is easily adapted for reflection, polarization (Kerr magneto-optical (MO)), Raman, super-resolution techniques, and other novel scanning probe imaging and spectroscopic designs. While collecting a variety of forms of optical images, the system can simultaneously monitor topographic information of a sample with an integrated tuning fork based shear force system. The instrument has the ability to image at room temperature and atmospheric pressure or under liquid. The core of the design is a field programmable gate array (FPGA) data acquisition card and a single, low cost computer to control the microscope with analog control circuitry using off-the-shelf available components. A detailed description of electronics, mechanical requirements, and software algorithms as well as examples of some different forms of the microscope developed so far are discussed.

  14. A digital magnetic resonance imaging spectrometer using digital signal processor and field programmable gate array.

    Science.gov (United States)

    Liang, Xiao; Binghe, Sun; Yueping, Ma; Ruyan, Zhao

    2013-05-01

    A digital spectrometer for low-field magnetic resonance imaging is described. A digital signal processor (DSP) is utilized as the pulse programmer on which a pulse sequence is executed as a subroutine. Field programmable gate array (FPGA) devices that are logically mapped into the external addressing space of the DSP work as auxiliary controllers of gradient control, radio frequency (rf) generation, and rf receiving separately. The pulse programmer triggers an event by setting the 32-bit control register of the corresponding FPGA, and then the FPGA automatically carries out the event function according to preset configurations in cooperation with other devices; accordingly, event control of the spectrometer is flexible and efficient. Digital techniques are in widespread use: gradient control is implemented in real-time by a FPGA; rf source is constructed using direct digital synthesis technique, and rf receiver is constructed using digital quadrature detection technique. Well-designed performance is achieved, including 1 μs time resolution of the gradient waveform, 1 μs time resolution of the soft pulse, and 2 MHz signal receiving bandwidth. Both rf synthesis and rf digitalization operate at the same 60 MHz clock, therefore, the frequency range of transmitting and receiving is from DC to ~27 MHz. A majority of pulse sequences have been developed, and the imaging performance of the spectrometer has been validated through a large number of experiments. Furthermore, the spectrometer is also suitable for relaxation measurement in nuclear magnetic resonance field.

  15. Misalignment-free signal propagation in nanomagnet arrays and logic gates with 45°-clocking field

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zheng; Kwon, Byung Seok; Krishnan, Kannan M., E-mail: kannanmk@uw.edu [Department of Materials Science and Engineering University of Washington, Box 352120, Seattle, Washington 98195 (United States)

    2014-05-07

    A key obstacle for the application of Magnetic Quantum-dot Cellular Automata (MQCA) is the misalignment of clocking field, which results in low stability for both signal propagations within nanomagnet array and logic operation in majority gates. Here, we demonstrate that a reversal clocking field applied at 45° off the hard axis, with progressively reduced amplitude, applied to a shape-tuned nanomagnet array fabricated by e-beam lithography, helps intrinsically eliminate the misalignment sensitivity of the elements and results in correct signal propagation. Further, least reversal steps and reduced field amplitude was required owing to the 45°-clocking field. This clocking field was also tested for majority gates (OR function) and characterized by Magnetic Force Microscopy demonstrating correct output. This novel design provides high stability for signal propagation and logic operation of MQCA and potentially paves way for its application.

  16. Influence of the gate dielectric on the mobility of rubrene single-crystal field-effect transistors

    NARCIS (Netherlands)

    Stassen, A.F.; De Boer, R.W.I.; Iosad, N.N.; Morpurgo, A.F.

    2004-01-01

    We have performed a comparative study of rubrene single-crystal field-effect transistors fabricated using different materials as gate insulator. For all materials, highly reproducible device characteristics are obtained. The achieved reproducibility permits one to observe that the mobility of the

  17. Tunable Zeeman-like Spin Splitting with Liquid Gated Field Effect Transistors

    Science.gov (United States)

    Yuan, Hongtao; Bahramy, M. S.; Morimoto, K.; Shimotani, H.; Arita, R.; Kloc, Ch.; Nagaosa, N.; Iwasa, Y.

    2012-02-01

    Generation of spin polarized electrons is the most critical step for developing spintronics applications. As an electric and nonmagnetic way to realize spin polarization in energy bands, spin-orbit interaction (SOI) has been widely used for spin manipulation in two-dimensional systems. For example, Rashba-type energy splitting with in-plane-polarized spins near γ point of Brillouin zone (BZ) is able to be modulated by electric field through tuning spatial inversion asymmetry. However, Zeeman-type energy splitting with out-of-plane spin polarization is known to be sensitive only to magnetic field and supposed never to be affected by external electric field. In this paper, we theoretically uncover and experimental confirm a perpendicular-electric-field induced giant Zeeman spin splitting at low symmetric K and K' points in a layered chalcogenide, 2H-WSe2. Ab initio band calculation and spin texture indicate that an electric field can make low-energy carriers spin-polarized in a out-of-plane Zeeman-type way and a tunable SOI is able to selectively control the size of splitting. A gate-induced crossover from weak localization to weak antilocalization in the magnetotransport serves as an experimental proof for the tunable SOI and spin polarization. The splitting energy deduced from quantum correction of magnetoconductance is as large as 120 meV and satisfied well with the band calculation for Zeeman-type splitting. This finding directly provides us with a new path-way for electrically initializing and manipulating electron spins for spintronics applications.

  18. Fabrication and independent control of patterned polymer gate for a few-layer WSe2 field-effect transistor

    Directory of Open Access Journals (Sweden)

    Sung Ju Hong

    2016-08-01

    Full Text Available We report the fabrication of a patterned polymer electrolyte for a two-dimensional (2D semiconductor, few-layer tungsten diselenide (WSe2 field-effect transistor (FET. We expose an electron-beam in a desirable region to form the patterned structure. The WSe2 FET acts as a p-type semiconductor in both bare and polymer-covered devices. We observe a highly efficient gating effect in the polymer-patterned device with independent gate control. The patterned polymer gate operates successfully in a molybdenum disulfide (MoS2 FET, indicating the potential for general applications to 2D semiconductors. The results of this study can contribute to large-scale integration and better flexibility in transition metal dichalcogenide (TMD-based electronics.

  19. Differential multiple-time-programmable memory cells by laterally coupled floating metal gate fin field-effect transistors

    Science.gov (United States)

    Hsu, Chia-Ling; Liao, Chu-Feng; Chien, Wei Yu; Chih, Yue-Der; Lin, Chrong Jung; King, Ya-Chin

    2017-04-01

    In this paper, we present a new differential multiple-time-programmable (MTP) memory cell with a novel slot contact coupling structure in the fin field-effect transistor (FinFET) CMOS process. This MTP cell contains a pair of floating metal gates to store differential data on a single cell. Through differential read operations, the cells are less susceptible to read error caused by cell-to-cell variations. In a nano-scaled FinFET process, the gate dielectric layer becomes too thin to retain charge in the floating gates for long periods of time. Differential cell design further extends the data lifetime, even with the serious charge-loss problem, and reduces the overall intellectual property (IP) area.

  20. Hydrogen-terminated diamond vertical-type metal oxide semiconductor field-effect transistors with a trench gate

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Masafumi, E-mail: inaba-ma@ruri.waseda.jp; Muta, Tsubasa; Kobayashi, Mikinori; Saito, Toshiki; Shibata, Masanobu; Matsumura, Daisuke; Kudo, Takuya; Hiraiwa, Atsushi [Graduate School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Kawarada, Hiroshi [Graduate School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan); Kagami Memorial Laboratory for Materials Science and Technology, Waseda University, 2-8-26 Nishiwaseda, Shinjuku, Tokyo 169-0051 (Japan)

    2016-07-18

    The hydrogen-terminated diamond surface (C-H diamond) has a two-dimensional hole gas (2DHG) layer independent of the crystal orientation. A 2DHG layer is ubiquitously formed on the C-H diamond surface covered by atomic-layer-deposited-Al{sub 2}O{sub 3}. Using Al{sub 2}O{sub 3} as a gate oxide, C-H diamond metal oxide semiconductor field-effect transistors (MOSFETs) operate in a trench gate structure where the diamond side-wall acts as a channel. MOSFETs with a side-wall channel exhibit equivalent performance to the lateral C-H diamond MOSFET without a side-wall channel. Here, a vertical-type MOSFET with a drain on the bottom is demonstrated in diamond with channel current modulation by the gate and pinch off.

  1. Current saturation and kink effect in zero-bandgap double-gate silicene field-effect transistors

    Science.gov (United States)

    Patel, Nishant; Choudhary, Sudhanshu

    2017-10-01

    Double gate silicene field effect transistor is investigated using Density Functional Theory (DFT) and Non-Equilibrium Green's Function (NEGF) formalism. The results suggest that with an increase in gate bias, bandgap is introduced in silicene which results in reduction in device current. The increase in silicene bandgap is also related to the reduction in channel length. It is observed that drain to source current (IDS) saturates on increasing drain to source voltage (VDS). On increasing VDS beyond saturation region, at some value of VDS kink effect is seen which is due to switching in the type of carriers at the drain end due to ambipolar channel. Transconductance (gm) is seen to reduce with reduction in channel length, however, gm improves with reduced oxide thickness due to better gate controllability. The output characteristics do not change much with oxide thickness.

  2. Hydrogen-terminated diamond vertical-type metal oxide semiconductor field-effect transistors with a trench gate

    Science.gov (United States)

    Inaba, Masafumi; Muta, Tsubasa; Kobayashi, Mikinori; Saito, Toshiki; Shibata, Masanobu; Matsumura, Daisuke; Kudo, Takuya; Hiraiwa, Atsushi; Kawarada, Hiroshi

    2016-07-01

    The hydrogen-terminated diamond surface (C-H diamond) has a two-dimensional hole gas (2DHG) layer independent of the crystal orientation. A 2DHG layer is ubiquitously formed on the C-H diamond surface covered by atomic-layer-deposited-Al2O3. Using Al2O3 as a gate oxide, C-H diamond metal oxide semiconductor field-effect transistors (MOSFETs) operate in a trench gate structure where the diamond side-wall acts as a channel. MOSFETs with a side-wall channel exhibit equivalent performance to the lateral C-H diamond MOSFET without a side-wall channel. Here, a vertical-type MOSFET with a drain on the bottom is demonstrated in diamond with channel current modulation by the gate and pinch off.

  3. Feasibility of a portable morphological scene change detection security system for field programmable gate arrays (FPGA)

    Science.gov (United States)

    Tickle, Andrew J.; Smith, Jeremy S.; Wu, Q. Henry

    2008-04-01

    In this paper, there is an investigation into the possibility of executing a Morphological Scene Change Detection (MSCD) system on a Field Programmable Gate Array (FPGA), which would allow its set up in virtually any location, with its purpose to detect intruders and raise an alarm to call security personal, and a signal to initial a lockdown of the local area. This paper will include how the system was scaled down from the full building multi-computer system, to an FPGA without losing any functionality using Altera's DSP Builder development tool. Also included is the analysis of the different situations which the system would encounter in the field, and their respective alarm triggering levels, these include indoors, outdoors, close-up, distance, high-brightness, low-light, bad weather, etc. The triggering mechanism is a pixel counter and threshold system, and its adaptive design will be included. All the results shown in this paper, will also be verified by MATLAB m-files running on a full desktop PC, to show that the results obtained from the FPGA based system are accurate.

  4. Ultrafast room temperature NH3 sensing with positively gated reduced graphene oxide field-effect transistors.

    Science.gov (United States)

    Lu, Ganhua; Yu, Kehan; Ocola, Leonidas E; Chen, Junhong

    2011-07-21

    Reduced graphene oxide (R-GO) under a positive gate potential (n-type conductance) exhibits an instantaneous response and fast recovery for NH(3) sensing, far superior to the performance in p-mode at zero/negative gate potential. Our findings have important implications for fast, repeatable, room temperature gas detection using graphene/R-GO.

  5. Batch fabrication of nanotubes suspended between microelectrodes

    DEFF Research Database (Denmark)

    Mateiu, Ramona Valentina; Stöckli, T.; Knapp, H. F.

    2007-01-01

    We report a fabrication method, which uses standard UV-lithography to pattern the catalyst for the chemical vapour deposition(CVD) of suspended double clamped single walled carbon nanotubes. By using an aqueous solution of Fe(NO3)3 the patterning of the catalyst material onto microelectrodes can...... be done with a simple lift-off process with standard photolithographic resist. An applied electric field is sustained between the microelectrodes during CVD to guide the nanotube growth. Comparison with simulations shows that the location and the orientation of the grown carbon nanotubes (CNT) correspond...... to the regions of maximum electric field, enabling accurate positioning of a nanotube by controlling the shape of the microelectrodes. The CNT bridges are deflected tens of nm when a DC voltage is applied between the nanotube and a gate microelectrode indicating that the clamping through the catalyst particles...

  6. On Field-Effect Photovoltaics: Gate Enhancement of the Power Conversion Efficiency in a Nanotube/Silicon-Nanowire Solar Cell.

    Science.gov (United States)

    Petterson, Maureen K; Lemaitre, Maxime G; Shen, Yu; Wadhwa, Pooja; Hou, Jie; Vasilyeva, Svetlana V; Kravchenko, Ivan I; Rinzler, Andrew G

    2015-09-30

    Recent years have seen a resurgence of interest in crystalline silicon Schottky junction solar cells distinguished by the use of low density of electronic states (DOS) nanocarbons (nanotubes, graphene) as the metal contacting the Si. Recently, unprecedented modulation of the power conversion efficiency in a single material system has been demonstrated in such cells by the use of electronic gating. The gate field induced Fermi level shift in the low-DOS carbon serves to enhance the junction built-in potential, while a gate field induced inversion layer at the Si surface, in regions remote from the junction, keeps the photocarriers well separated there, avoiding recombination at surface traps and defects (a key loss mechanism). Here, we extend these results into the third dimension of a vertical Si nanowire array solar cell. A single wall carbon nanotube layer engineered to contact virtually each n-Si nanowire tip extracts the minority carriers, while an ionic liquid electrolytic gate drives the nanowire body into inversion. The enhanced light absorption of the vertical forest cell, at 100 mW/cm(2) AM1.5G illumination, results in a short-circuit current density of 35 mA/cm(2) and associated power conversion efficiency of 15%. These results highlight the use of local fields as opposed to surface passivation as a means of avoiding front surface recombination. A deleterious electrochemical reaction of the silicon due to the electrolyte gating is shown to be caused by oxygen/water entrained in the ionic liquid electrolyte. While encapsulation can avoid the issue, a nonencapsulation-based approach is also implemented.

  7. Development and simulation of soft morphological operators for a field programmable gate array

    Science.gov (United States)

    Tickle, Andrew J.; Harvey, Paul K.; Smith, Jeremy S.; Wu, Q. Henry

    2013-04-01

    In image processing applications, soft mathematical morphology (MM) can be employed for both binary and grayscale systems and is derived from set theory. Soft MM techniques have improved behavior over standard morphological operations in noisy environments, as they can preserve small details within an image. This makes them suitable for use in image processing applications on portable field programmable gate arrays for tasks such as robotics and security. We explain how the systems were developed using Altera's DSP Builder in order to provide optimized code for the many different devices currently on the market. Also included is how the circuits can be inserted and combined with previously developed work in order to increase their functionality. The testing procedures involved loading different images into these systems and analyzing the outputs against MATLAB-generated validation images. A set of soft morphological operations are described, which can then be applied to various tasks and easily modified in size via altering the line buffer settings inside the system to accommodate a range of image attributes ranging from image sizes such as 320×240 pixels for basic webcam imagery up to high quality 4000×4000 pixel images for military applications.

  8. Field Programmable Gate Array Reliability Analysis Using the Dynamic Flowgraph Methodology

    Directory of Open Access Journals (Sweden)

    Phillip McNelles

    2016-10-01

    Full Text Available Field programmable gate array (FPGA-based systems are thought to be a practical option to replace certain obsolete instrumentation and control systems in nuclear power plants. An FPGA is a type of integrated circuit, which is programmed after being manufactured. FPGAs have some advantages over other electronic technologies, such as analog circuits, microprocessors, and Programmable Logic Controllers (PLCs, for nuclear instrumentation and control, and safety system applications. However, safety-related issues for FPGA-based systems remain to be verified. Owing to this, modeling FPGA-based systems for safety assessment has now become an important point of research. One potential methodology is the dynamic flowgraph methodology (DFM. It has been used for modeling software/hardware interactions in modern control systems. In this paper, FPGA logic was analyzed using DFM. Four aspects of FPGAs are investigated: the “IEEE 1164 standard,” registers (D flip-flops, configurable logic blocks, and an FPGA-based signal compensator. The ModelSim simulations confirmed that DFM was able to accurately model those four FPGA properties, proving that DFM has the potential to be used in the modeling of FPGA-based systems. Furthermore, advantages of DFM over traditional reliability analysis methods and FPGA simulators are presented, along with a discussion of potential issues with using DFM for FPGA-based system modeling.

  9. Gate-Sensing Coherent Charge Oscillations in a Silicon Field-Effect Transistor.

    Science.gov (United States)

    Gonzalez-Zalba, M Fernando; Shevchenko, Sergey N; Barraud, Sylvain; Johansson, J Robert; Ferguson, Andrew J; Nori, Franco; Betz, Andreas C

    2016-03-09

    Quantum mechanical effects induced by the miniaturization of complementary metal-oxide-semiconductor (CMOS) technology hamper the performance and scalability prospects of field-effect transistors. However, those quantum effects, such as tunneling and coherence, can be harnessed to use existing CMOS technology for quantum information processing. Here, we report the observation of coherent charge oscillations in a double quantum dot formed in a silicon nanowire transistor detected via its dispersive interaction with a radio frequency resonant circuit coupled via the gate. Differential capacitance changes at the interdot charge transitions allow us to monitor the state of the system in the strong-driving regime where we observe the emergence of Landau-Zener-Stückelberg-Majorana interference on the phase response of the resonator. A theoretical analysis of the dispersive signal demonstrates that quantum and tunneling capacitance changes must be included to describe the qubit-resonator interaction. Furthermore, a Fourier analysis of the interference pattern reveals a charge coherence time, T2 ≈ 100 ps. Our results demonstrate charge coherent control and readout in a simple silicon transistor and open up the possibility to implement charge and spin qubits in existing CMOS technology.

  10. pH sensing properties of graphene solution-gated field-effect transistors

    Science.gov (United States)

    Mailly-Giacchetti, Benjamin; Hsu, Allen; Wang, Han; Vinciguerra, Vincenzo; Pappalardo, Francesco; Occhipinti, Luigi; Guidetti, Elio; Coffa, Salvatore; Kong, Jing; Palacios, Tomás

    2013-08-01

    The use of graphene grown by chemical vapor deposition to fabricate solution-gated field-effect transistors (SGFET) on different substrates is reported. SGFETs were fabricated using graphene transferred on poly(ethylene 2,6-naphthalenedicarboxylate) substrate in order to study the influence of using a flexible substrate for pH sensing. Furthermore, in order to understand the influence of fabrication-related residues on top of the graphene surface, a fabrication method was developed for graphene-on-SiO2 SGFETs that enables to keep a graphene surface completely clean of any residues at the end of the fabrication. We were then able to demonstrate that the electrical response of the SGFET devices to pH does not depend either on the specific substrate on which graphene is transferred or on the existence of a moderate amount of fabrication-related residues on top of the graphene surface. These considerations simplify and ease the design and fabrication of graphene pH sensors, paving the way for developing low cost, flexible, and transparent graphene sensors on plastic. We also show that the surface transfer doping mechanism does not have significant influence on the pH sensing response. This highlights that the adsorption of hydroxyl and hydronium ions on the graphene surface due to the charging of the electrical double layer capacitance is responsible for the pH sensing mechanism.

  11. SOTB Implementation of a Field Programmable Gate Array with Fine-Grained Vt Programmability

    Directory of Open Access Journals (Sweden)

    Masakazu Hioki

    2014-07-01

    Full Text Available Field programmable gate arrays (FPGAs are one of the most widespread reconfigurable devices in which various functions can be implemented by storing circuit connection information and logic values into configuration memories. One of the most important issues in the modern FPGA is the reduction of its static leakage power consumption. Flex Power FPGA, which has been proposed to overcome this problem, uses a body biasing technique to implement the fine-grained threshold voltage (Vt programmability in the FPGA. A low-Vt state can be assigned only to the component circuits along the critical path of the application design mapped on the FPGA, so that the static leakage power consumption can be reduced drastically. Flex Power FPGA is an important application target for the SOTB (silicon on thin buried oxide device, which features a wide-range body biasing ability and the high sensitivity of Vt variation by body biasing, resulting in a drastic subthreshold leakage current reduction caused by static leakage power. In this paper, the Flex Power FPGA test chip is fabricated in SOTB technology, and the functional test and performance evaluation of a mapped 32-bit binary counter circuit are performed successfully. As a result, a three orders of magnitude static leakage reduction with a bias range of 2.1 V demonstrates the excellent Vt controllability of the SOTB transistors, and the 1.2 V bias difference achieves a 50× leakage reduction without degrading speed.

  12. Using field programmable gate array hardware for the performance improvement of ultrasonic wave propagation imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Shan, Jaffry Syed [Hamdard University, Karachi (Pakistan); Abbas, Syed Haider; Lee, Jung Ryul [Dept. of Aerospace Engineering, Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Kang, Dong Hoon [Advanced Materials Research Team, Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2015-12-15

    Recently, wave propagation imaging based on laser scanning-generated elastic waves has been intensively used for nondestructive inspection. However, the proficiency of the conventional software based system reduces when the scan area is large since the processing time increases significantly due to unavoidable processor multitasking, where computing resources are shared with multiple processes. Hence, the field programmable gate array (FPGA) was introduced for a wave propagation imaging method in order to obtain extreme processing time reduction. An FPGA board was used for the design, implementing post-processing ultrasonic wave propagation imaging (UWPI). The results were compared with the conventional system and considerable improvement was observed, with at least 78% (scanning of 100x100mm{sup 2} with 0.5 mm interval) to 87.5% (scanning of 200x200mm{sup 2} with 0.5 mm interval) less processing time, strengthening the claim for the research. This new concept to implement FPGA technology into the UPI system will act as a break-through technology for full-scale automatic inspection.

  13. Full image-processing pipeline in field-programmable gate array for a small endoscopic camera

    Science.gov (United States)

    Mostafa, Sheikh Shanawaz; Sousa, L. Natércia; Ferreira, Nuno Fábio; Sousa, Ricardo M.; Santos, Joao; Wäny, Martin; Morgado-Dias, F.

    2017-01-01

    Endoscopy is an imaging procedure used for diagnosis as well as for some surgical purposes. The camera used for the endoscopy should be small and able to produce a good quality image or video, to reduce discomfort of the patients, and to increase the efficiency of the medical team. To achieve these fundamental goals, a small endoscopy camera with a footprint of 1 mm×1 mm×1.65 mm is used. Due to the physical properties of the sensors and human vision system limitations, different image-processing algorithms, such as noise reduction, demosaicking, and gamma correction, among others, are needed to faithfully reproduce the image or video. A full image-processing pipeline is implemented using a field-programmable gate array (FPGA) to accomplish a high frame rate of 60 fps with minimum processing delay. Along with this, a viewer has also been developed to display and control the image-processing pipeline. The control and data transfer are done by a USB 3.0 end point in the computer. The full developed system achieves real-time processing of the image and fits in a Xilinx Spartan-6LX150 FPGA.

  14. Field programmable gate array reliability analysis using the dynamic flow graph methodology

    Energy Technology Data Exchange (ETDEWEB)

    McNelles, Phillip; Lu, Lixuan [Faculty of Energy Systems and Nuclear Science, University of Ontario Institute of Technology (UOIT), Ontario (Canada)

    2016-10-15

    Field programmable gate array (FPGA)-based systems are thought to be a practical option to replace certain obsolete instrumentation and control systems in nuclear power plants. An FPGA is a type of integrated circuit, which is programmed after being manufactured. FPGAs have some advantages over other electronic technologies, such as analog circuits, microprocessors, and Programmable Logic Controllers (PLCs), for nuclear instrumentation and control, and safety system applications. However, safety-related issues for FPGA-based systems remain to be verified. Owing to this, modeling FPGA-based systems for safety assessment has now become an important point of research. One potential methodology is the dynamic flowgraph methodology (DFM). It has been used for modeling software/hardware interactions in modern control systems. In this paper, FPGA logic was analyzed using DFM. Four aspects of FPGAs are investigated: the 'IEEE 1164 standard', registers (D flip-flops), configurable logic blocks, and an FPGA-based signal compensator. The ModelSim simulations confirmed that DFM was able to accurately model those four FPGA properties, proving that DFM has the potential to be used in the modeling of FPGA-based systems. Furthermore, advantages of DFM over traditional reliability analysis methods and FPGA simulators are presented, along with a discussion of potential issues with using DFM for FPGA-based system modeling.

  15. Field-programmable gate array-controlled sweep velocity-locked laser pulse generator

    Science.gov (United States)

    Chen, Zhen; Hefferman, Gerald; Wei, Tao

    2017-05-01

    A field-programmable gate array (FPGA)-controlled sweep velocity-locked laser pulse generator (SV-LLPG) design based on an all-digital phase-locked loop (ADPLL) is proposed. A distributed feedback laser with modulated injection current was used as a swept-frequency laser source. An open-loop predistortion modulation waveform was calibrated using a feedback iteration method to initially improve frequency sweep linearity. An ADPLL control system was then implemented using an FPGA to lock the output of a Mach-Zehnder interferometer that was directly proportional to laser sweep velocity to an on-board system clock. Using this system, linearly chirped laser pulses with a sweep bandwidth of 111.16 GHz were demonstrated. Further testing evaluating the sensing utility of the system was conducted. In this test, the SV-LLPG served as the swept laser source of an optical frequency-domain reflectometry system used to interrogate a subterahertz range fiber structure (sub-THz-FS) array. A static strain test was then conducted and linear sensor results were observed.

  16. Implementation of fractional order integrator/differentiator on field programmable gate array

    Directory of Open Access Journals (Sweden)

    K.P.S. Rana

    2016-06-01

    Full Text Available Concept of fractional order calculus is as old as the regular calculus. With the advent of high speed and cost effective computing power, now it is possible to model the real world control and signal processing problems using fractional order calculus. For the past two decades, applications of fractional order calculus, in system modeling, control and signal processing, have grown rapidly. This paper presents a systematic procedure for hardware implementation of the basic operators of fractional calculus i.e. fractional integrator and derivative, using Grünwald–Letnikov definition, on field programmable gate array (FPGA in LabVIEW environment. The simulation and hardware implementation results for fractional order integrator and derivative of sinusoid and square waveform signals for some selected fractional orders have been presented. A close agreement between the simulated and the experimental results demonstrated the suitability of FPGA device in fractional order control and signal processing applications. LabVIEW being one of the finest tools for measurement and control, and signal processing applications the fractional order operator implementation is expected to further enhance the capability of the tool to cater to the needs of advanced experimental research employing fractional order operators.

  17. Design techniques for a stable operation of cryogenic field-programmable gate arrays

    Science.gov (United States)

    Homulle, Harald; Visser, Stefan; Patra, Bishnu; Charbon, Edoardo

    2018-01-01

    In this paper, we show how a deep-submicron field-programmable gate array (FPGA) can be operated more stably at extremely low temperatures through special firmware design techniques. Stability at low temperatures is limited through long power supply wires and reduced performance of various printed circuit board components commonly employed at room temperature. Extensive characterization of these components shows that the majority of decoupling capacitor types and voltage regulators are not well behaved at cryogenic temperatures, asking for an ad hoc solution to stabilize the FPGA supply voltage, especially for sensitive applications. Therefore, we have designed a firmware that enforces a constant power consumption, so as to stabilize the supply voltage in the interior of the FPGA. The FPGA is powered with a supply at several meters distance, causing significant resistive voltage drop and thus fluctuations on the local supply voltage. To achieve the stabilization, the variation in digital logic speed, which directly corresponds to changes in supply voltage, is constantly measured and corrected for through a tunable oscillator farm, implemented on the FPGA. The impact of the stabilization technique is demonstrated together with a reconfigurable analog-to-digital converter (ADC), completely implemented in the FPGA fabric and operating at 15 K. The ADC performance can be improved by at most 1.5 bits (effective number of bits) thanks to the more stable supply voltage. The method is versatile and robust, enabling seamless porting to other FPGA families and configurations.

  18. Field evaluation of the error arising from inadequate time averaging in the standard use of depth-integrating suspended-sediment samplers

    Science.gov (United States)

    Topping, David J.; Rubin, David M.; Wright, Scott A.; Melis, Theodore S.

    2011-01-01

    Several common methods for measuring suspended-sediment concentration in rivers in the United States use depth-integrating samplers to collect a velocity-weighted suspended-sediment sample in a subsample of a river cross section. Because depth-integrating samplers are always moving through the water column as they collect a sample, and can collect only a limited volume of water and suspended sediment, they collect only minimally time-averaged data. Four sources of error exist in the field use of these samplers: (1) bed contamination, (2) pressure-driven inrush, (3) inadequate sampling of the cross-stream spatial structure in suspended-sediment concentration, and (4) inadequate time averaging. The first two of these errors arise from misuse of suspended-sediment samplers, and the third has been the subject of previous study using data collected in the sand-bedded Middle Loup River in Nebraska. Of these four sources of error, the least understood source of error arises from the fact that depth-integrating samplers collect only minimally time-averaged data. To evaluate this fourth source of error, we collected suspended-sediment data between 1995 and 2007 at four sites on the Colorado River in Utah and Arizona, using a P-61 suspended-sediment sampler deployed in both point- and one-way depth-integrating modes, and D-96-A1 and D-77 bag-type depth-integrating suspended-sediment samplers. These data indicate that the minimal duration of time averaging during standard field operation of depth-integrating samplers leads to an error that is comparable in magnitude to that arising from inadequate sampling of the cross-stream spatial structure in suspended-sediment concentration. This random error arising from inadequate time averaging is positively correlated with grain size and does not largely depend on flow conditions or, for a given size class of suspended sediment, on elevation above the bed. Averaging over time scales >1 minute is the likely minimum duration required

  19. High carrier mobility of CoPc wires based field-effect transistors using bi-layer gate dielectric

    Directory of Open Access Journals (Sweden)

    Murali Gedda

    2013-11-01

    Full Text Available Polyvinyl alcohol (PVA and anodized Al2O3 layers were used as bi-layer gate for the fabrication of cobalt phthalocyanine (CoPc wire base field-effect transistors (OFETs. CoPc wires were grown on SiO2 surfaces by organic vapor phase deposition method. These devices exhibit a field-effect carrier mobility (μEF value of 1.11 cm2/Vs. The high carrier mobility for CoPc molecules is attributed to the better capacitive coupling between the channel of CoPc wires and the gate through organic-inorganic dielectric layer. Our measurements also demonstrated the way to determine the thicknesses of the dielectric layers for a better process condition of OFETs.

  20. Electron energy dissipation model of gate dielectric progressive breakdown in n- and p-channel field effect transistors

    Science.gov (United States)

    Lombardo, S.; Wu, E. Y.; Stathis, J. H.

    2017-08-01

    We report the data and a model showing that the energy loss experienced by the carriers flowing through breakdown spots is the primary cause of progressive breakdown spot growth. The experiments are performed in gate dielectrics of metal-oxide-semiconductor (MOS) devices subjected to accelerated high electric field constant voltage stress under inversion conditions. The model is analytical and contains few free parameters of clear physical meaning. This is compared to a large set of data on breakdown transients at various oxide thicknesses, stress voltages, and temperatures, both in cases of n-channel and p-channel transistors and polycrystalline Si/oxynitride/Si and metal gate/high k dielectric/Si gate stacks. The basic idea is that the breakdown transient is due to the growth of one or more filaments in the dielectric promoted by electromigration driven by the energy lost by the electrons traveling through the breakdown spots. Both cases of polycrystalline Si/oxynitride/Si and metal gate/high-k dielectric/Si MOS structures are investigated. The best fit values of the model to the data, reported and discussed in the paper, consistently describe a large set of data. The case of simultaneous growth of multiple progressive breakdown spots in the same device is also discussed in detail.

  1. Single Event Test Methodologies and System Error Rate Analysis for Triple Modular Redundant Field Programmable Gate Arrays

    Science.gov (United States)

    Allen, Gregory; Edmonds, Larry D.; Swift, Gary; Carmichael, Carl; Tseng, Chen Wei; Heldt, Kevin; Anderson, Scott Arlo; Coe, Michael

    2010-01-01

    We present a test methodology for estimating system error rates of Field Programmable Gate Arrays (FPGAs) mitigated with Triple Modular Redundancy (TMR). The test methodology is founded in a mathematical model, which is also presented. Accelerator data from 90 nm Xilins Military/Aerospace grade FPGA are shown to fit the model. Fault injection (FI) results are discussed and related to the test data. Design implementation and the corresponding impact of multiple bit upset (MBU) are also discussed.

  2. Modeling of subthreshold characteristics of short channel junctionless cylindrical surrounding-gate nanowire metal-oxide-silicon field effect transistors

    Science.gov (United States)

    Jin, Xiaoshi; Liu, Xi; Lee, Jung-Hee; Lee, Jong-Ho

    2014-01-01

    A subthreshold model of short-channel junctionless field effect transistors with cylindrical surrounding-gate nanowire structure has been proposed. It was based on an approximated solution of two-dimensional Poisson's equation. The derivation of this model was introduced and the accuracy of the proposed models have been verified by comparison with both previous models and the SILVACO Atlas TCAD simulation results, which show good agreement.

  3. Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects

    OpenAIRE

    Pall, Martin L

    2013-01-01

    The direct targets of extremely low and microwave frequency range electromagnetic fields (EMFs) in producing non-thermal effects have not been clearly established. However, studies in the literature, reviewed here, provide substantial support for such direct targets. Twenty-three studies have shown that voltage-gated calcium channels (VGCCs) produce these and other EMF effects, such that the L-type or other VGCC blockers block or greatly lower diverse EMF effects. Furthermore, the voltage-gat...

  4. Field programmable gate array–based servo control integrated chip for a six-axis articulated robot manipulator

    Directory of Open Access Journals (Sweden)

    Ying-Shieh Kung

    2016-05-01

    Full Text Available The objective of this article is to build a field programmable gate array–based six-axis servo control integrated chip which can integrate the function of a motion trajectory planning and the function of six position/speed/current servo controllers into one integrated chip. In the work, first, a mathematical modeling of a robot manipulator with the actuator using permanent magnet synchronous motor is derived. Second, the proportional controller in the position loop, a proportional–integral controller in the speed loop and a vector controller in the current loop for each axis are applied. Third, a system on a programmable chip technology which comprises an Altera field programmable gate array chip and an embedded soft-core Nios-II processor is considered to develop the proposed servo control integrated chip. However, in the servo control integrated chip, it has two modules. The first module is an embedded soft-core Nios-II processor which is used to generate the motion trajectory planning by software. The second module presents a six-axis servo controller intellectual property by hardware which is applied to execute six position/speed/current controllers. Therefore, the function of a motion trajectory command and the function of six position/speed/current servo controllers for a six-axis robot manipulator can be integrated into one field programmable gate array. Finally, to verify the effectiveness and correctness of the proposed field programmable gate array–based servo control integrated chip, a six-axis robot manipulator is applied and some experimental results are demonstrated.

  5. 3D CFD simulations of trailing suction hopper dredger plume mixing: a parameter study of near-field conditions influencing the suspended sediment source flux.

    Science.gov (United States)

    de Wit, Lynyrd; Talmon, A M; van Rhee, C

    2014-11-15

    Frequency, duration and intensity of stresses like turbidity and sedimentation caused by dredging must be known to determine the environmental impact of dredging projects. These stresses depend on the amount of sediment spill from a dredger and on how much of this spill still is in suspension near environmentally sensitive areas. Near-field mixing close to a dredger influences the deposition behaviour of the sediment spill. This is investigated systematically with computational fluid dynamics simulations for 136 different conditions of trailing suction hopper dredger overflow sediment plume mixing. Most important influences are found for the ambient depth and the crossflow velocity (vector sum of the dredging speed and the ambient velocity), which can result in a completely different suspended sediment source flux behind the dredger. The simulation results are translated into mathematical relations to predict the suspended sediment source flux without computational effort. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. The Use of Field Programmable Gate Arrays (FPGA) in Small Satellite Communication Systems

    Science.gov (United States)

    Varnavas, Kosta; Sims, William Herbert; Casas, Joseph

    2015-01-01

    This paper will describe the use of digital Field Programmable Gate Arrays (FPGA) to contribute to advancing the state-of-the-art in software defined radio (SDR) transponder design for the emerging SmallSat and CubeSat industry and to provide advances for NASA as described in the TAO5 Communication and Navigation Roadmap (Ref 4). The use of software defined radios (SDR) has been around for a long time. A typical implementation of the SDR is to use a processor and write software to implement all the functions of filtering, carrier recovery, error correction, framing etc. Even with modern high speed and low power digital signal processors, high speed memories, and efficient coding, the compute intensive nature of digital filters, error correcting and other algorithms is too much for modern processors to get efficient use of the available bandwidth to the ground. By using FPGAs, these compute intensive tasks can be done in parallel, pipelined fashion and more efficiently use every clock cycle to significantly increase throughput while maintaining low power. These methods will implement digital radios with significant data rates in the X and Ka bands. Using these state-of-the-art technologies, unprecedented uplink and downlink capabilities can be achieved in a 1/2 U sized telemetry system. Additionally, modern FPGAs have embedded processing systems, such as ARM cores, integrated inside the FPGA allowing mundane tasks such as parameter commanding to occur easily and flexibly. Potential partners include other NASA centers, industry and the DOD. These assets are associated with small satellite demonstration flights, LEO and deep space applications. MSFC currently has an SDR transponder test-bed using Hardware-in-the-Loop techniques to evaluate and improve SDR technologies.

  7. Influence of the gate position on source-to-drain resistance in AlGaN/AlN/GaN heterostructure field-effect transistors

    Science.gov (United States)

    Liu, Yan; Lin, Zhaojun; Cui, Peng; Zhao, Jingtao; Fu, Chen; Yang, Ming; Lv, Yuanjie

    2017-08-01

    Using a suitable dual-gate structure, the source-to-drain resistance (RSD) of AlGaN/AlN/GaN heterostructure field-effect transistor (HFET) with varying gate position has been studied at room temperature. The theoretical and experimental results have revealed a dependence of RSD on the gate position. The variation of RSD with the gate position is found to stem from the polarization Coulomb field (PCF) scattering. This finding is of great benefit to the optimization of the performance of AlGaN/AlN/GaN HFET. Especially, when the AlGaN/AlN/GaN HFET works as a microwave device, it is beneficial to achieve the impedance matching by designing the appropriate gate position based on PCF scattering.

  8. Influence of the gate position on source-to-drain resistance in AlGaN/AlN/GaN heterostructure field-effect transistors

    Directory of Open Access Journals (Sweden)

    Yan Liu

    2017-08-01

    Full Text Available Using a suitable dual-gate structure, the source-to-drain resistance (RSD of AlGaN/AlN/GaN heterostructure field-effect transistor (HFET with varying gate position has been studied at room temperature. The theoretical and experimental results have revealed a dependence of RSD on the gate position. The variation of RSD with the gate position is found to stem from the polarization Coulomb field (PCF scattering. This finding is of great benefit to the optimization of the performance of AlGaN/AlN/GaN HFET. Especially, when the AlGaN/AlN/GaN HFET works as a microwave device, it is beneficial to achieve the impedance matching by designing the appropriate gate position based on PCF scattering.

  9. Improved performance of nanoscale junctionless tunnel field-effect transistor based on gate engineering approach

    Science.gov (United States)

    Molaei Imen Abadi, Rouzbeh; Sedigh Ziabari, Seyed Ali

    2016-11-01

    In this paper, a first qualitative study on the performance characteristics of dual-work function gate junctionless TFET (DWG-JLTFET) on the basis of energy band profile modulation is investigated. A dual-work function gate technique is used in a JLTFET in order to create a downward band bending on the source side similar to PNPN structure. Compared with the single-work function gate junctionless TFET (SWG-JLTFET), the numerical simulation results demonstrated that the DWG-JLTFET simultaneously optimizes the ON-state current, the OFF-state leakage current, and the threshold voltage and also improves average subthreshold slope. It is illustrated that if appropriate work functions are selected for the gate materials on the source side and the drain side, the JLTFET exhibits a considerably improved performance. Furthermore, the optimization design of the tunnel gate length ( L Tun) for the proposed DWG-JLTFET is studied. All the simulations are done in Silvaco TCAD for a channel length of 20 nm using the nonlocal band-to-band tunneling (BTBT) model.

  10. Performance analysis of InGaAs/GaAsP heterojunction double gate tunnel field effect transistor

    Science.gov (United States)

    Ahish, S.; Sharma, Dheeraj; Vasantha, M. H.; Kumar, Y. B. N.

    2017-03-01

    In this paper, analog/RF performance of InGaAs/GaAsP heterojunction double gate tunnel field effect transistor (HJTFET) has been explored. A highly doped n+ layer is placed at the Source-Channel junction in order to improve the horizontal electric field component and thus, improve the realiability of the device. The analog performance of the device is analysed by extracting current-voltage characteristics, transcondutance (gm), gate-to-drain capacitance (Cgd) and gate-to-source capacitance (Cgs). Further, RF performance of the device is evaluated by obtaining cut-off frequency (fT) and Gain Bandwidth (GBW) product. ION /IOFF ratio equal to ≈ 109, subthreshold slope of 27 mV/dec, maximum fT of 2.1 THz and maximum GBW of 484 GHz were achieved. Also, the impact of temperature variation on the linearity performance of the device has been investigated. Furthermore, the circuit level performance of the device is performed by implementing a Common Source (CS) amplifier; maximum gain of 31.11 dB and 3-dB cut-off frequency equal to 91.2 GHz were achieved for load resistance (RL) = 17.5 KΩ.

  11. Au-gated SrTiO{sub 3} field-effect transistors with large electron concentration and current modulation

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Amit, E-mail: averma@nd.edu; Jena, Debdeep [Department of Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States); Raghavan, Santosh; Stemmer, Susanne [Materials Department, University of California, Santa Barbara, California 93106 (United States)

    2014-09-15

    We report the fabrication of low-leakage rectifying Pt and Au Schottky diodes and Au-gated metal-semiconductor field effect transistors (MESFETs) on n-type SrTiO{sub 3} thin films grown by hybrid molecular beam epitaxy. In agreement with previous studies, we find that compared to Pt, Au provides a higher Schottky barrier height with SrTiO{sub 3}. As a result of the large dielectric constant of SrTiO{sub 3} and the large Schottky barrier height of Au, the Au-gated MESFETs are able to modulate ∼1.6 × 10{sup 14 }cm{sup −2} electron density, the highest modulation yet achieved using metal gates in any material system. These MESFETs modulate current densities up to ∼68 mA/mm, ∼20× times larger than the best demonstrated SrTiO{sub 3} MESFETs. We also discuss the roles of the interfacial layer, and the field-dependent dielectric constant of SrTiO{sub 3} in increasing the pinch off voltage of the MESFET.

  12. Flexible, Low-Cost Sensor Based on Electrolyte Gated Carbon Nanotube Field Effect Transistor for Organo-Phosphate Detection.

    Science.gov (United States)

    Bhatt, Vijay Deep; Joshi, Saumya; Becherer, Markus; Lugli, Paolo

    2017-05-18

    A flexible enzymatic acetylcholinesterase biosensor based on an electrolyte-gated carbon nanotube field effect transistor is demonstrated. The enzyme immobilization is done on a planar gold gate electrode using 3-mercapto propionic acid as the linker molecule. The sensor showed good sensing capability as a sensor for the neurotransmitter acetylcholine, with a sensitivity of 5.7 μA/decade, and demonstrated excellent specificity when tested against interfering analytes present in the body. As the flexible sensor is supposed to suffer mechanical deformations, the endurance of the sensor was measured by putting it under extensive mechanical stress. The enzymatic activity was inhibited by more than 70% when the phosphate-buffered saline (PBS) buffer was spiked with 5 mg/mL malathion (an organophosphate) solution. The biosensor was successfully challenged with tap water and strawberry juice, demonstrating its usefulness as an analytical tool for organophosphate detection.

  13. Silicon Carbide Junction Field Effect Transistor Digital Logic Gates Demonstrated at 600 deg. C

    Science.gov (United States)

    Neudeck, Philip G.

    1998-01-01

    The High Temperature Integrated Electronics and Sensors (HTIES) Program at the NASA Lewis Research Center is currently developing silicon carbide (SiC) for use in harsh conditions where silicon, the semiconductor used in nearly all of today's electronics, cannot function. The HTIES team recently fabricated and demonstrated the first semiconductor digital logic gates ever to function at 600 C.

  14. Field Plate Optimization in Low-Power High-Gain Source-Gated Transistors

    NARCIS (Netherlands)

    Sporea,R.A.; Trainor, M.J.; Young, N.D.; Shannon, J.M.; Silva, S.R.P.

    2012-01-01

    Source-gated transistors (SGTs) have potentially very high output impedance and low saturation voltages, which make them ideal as building blocks for high performance analog circuits fabricated in thin-film technologies. The quality of the saturation is greatly influenced by the design of the

  15. A bistable electromagnetically actuated rotary gate microvalve

    Science.gov (United States)

    Luharuka, Rajesh; Hesketh, Peter J.

    2008-03-01

    Two types of rotary gate microvalves are developed for flow modulation in microfluidic systems. These microvalves have been tested for an open flow rate of up to 100 sccm and operate under a differential pressure of 6 psig with flow modulation of up to 100. The microvalve consists of a suspended gate that rotates in the plane of the chip to regulate flow through the orifice. The gate is suspended by a novel fully compliant in-plane rotary bistable micromechanism (IPRBM) that advantageously constrains the gate in all degrees of freedom except for in-plane rotational motion. Multiple inlet/outlet orifices provide flexibility of operating the microvalve in three different flow configurations. The rotary gate microvalve is switched with an external electromagnetic actuator. The suspended gate is made of a soft magnetic material and its electromagnetic actuation is based on the operating principle of a variable-reluctance stepper motor.

  16. Effects of low energy E-beam irradiation on graphene and graphene field effect transistors and raman metrology of graphene on split gate test structures

    Science.gov (United States)

    Rao, Gayathri S.

    2011-12-01

    Apart from its compelling performance in conventional nanoelectronic device geometries, graphene is an appropriate candidate to study certain interesting phenomenon (e.g. the Veselago lens effect) predicted on the basis of its linear electron dispersion relation. A key requirement for the observation of such phenomenon in graphene and for its use in conventional field-effect transistor (FET) devices is the need to minimize defects such as consisting of -- or resulting from -- adsorbates and lattice non-uniformities, and reduce deleterious substrate effects. Consequently the investigation of the origin and interaction of defects in the graphene lattice is essential to improve and tailor graphene-based device performance. In this thesis, optical spectroscopic studies on the influence of low-energy electron irradiation on adsorbate-induced defectivity and doping for substrate supported and suspended graphene were carried out along with spectroscopic and transport measurements on graphene FETs. A comparative investigation of the effects of single-step versus multi-step, low-energy electron irradiation (500 eV) on suspended, substrate supported graphene and on graphene FETs is reported. E-beam irradiation (single-step and multi-step) of substrate-supported graphene resulted in an increase in the Raman ID/IG ratio largely from hydrogenation due to radiolysis of the interfacial water layer between the graphene and the SiO2 substrate and from irradiated surface adsorbates. GFETs subjected to single and multi-step irradiation showed n-doping from CNP (charge neutrality point) shift of ˜ -8 and ˜ -16 V respectively. Correlation of this data with Raman analysis of suspended and supported graphene samples implied a strong role of the substrate and irradiation sequence in determining the level of doping. A correspondingly higher reduction in mobility per incident electron was also observed for GFETs subjected to multi-step irradiation compared to single step, in line with

  17. The effect of compressibility, rotation and magnetic field on thermal instability of Walters’ fluid permeated with suspended particles in porous medium

    Directory of Open Access Journals (Sweden)

    Aggarwal Kumar Amrish

    2014-01-01

    Full Text Available The purpose of this paper is to study the effects of compressibility, rotation, magnetic field and suspended particles on thermal stability of a layer of visco-elastic Walters’ (model fluid in porous medium. Using linearized theory and normal mode analysis, dispersion relation has been obtained. In case of stationary convection, it is found that the rotation has stabilizing effect on the system. The magnetic field may have destabilizing effect on the system in the presence of rotation while in the absence of rotation it always has stabilizing effect. The medium permeability has destabilizing effect on the system in the absence of rotation while in the presence of rotation it may have stabilizing effect. The suspended particles and compressibility always have destabilizing effect. Due to vanishing of visco-elastic parameter, the compressible visco-elastic fluid behaves like Newtonian fluid. Graphs have also been plotted to depict the stability characteristics. The viscoelasticity, magnetic field and rotation are found to introduce oscillatory modes into the system which were non-existent in their absence.

  18. Water-Gated n-Type Organic Field-Effect Transistors for Complementary Integrated Circuits Operating in an Aqueous Environment.

    Science.gov (United States)

    Porrazzo, Rossella; Luzio, Alessandro; Bellani, Sebastiano; Bonacchini, Giorgio Ernesto; Noh, Yong-Young; Kim, Yun-Hi; Lanzani, Guglielmo; Antognazza, Maria Rosa; Caironi, Mario

    2017-01-31

    The first demonstration of an n-type water-gated organic field-effect transistor (WGOFET) is here reported, along with simple water-gated complementary integrated circuits, in the form of inverting logic gates. For the n-type WGOFET active layer, high-electron-affinity organic semiconductors, including naphthalene diimide co-polymers and a soluble fullerene derivative, have been compared, with the latter enabling a high electric double layer capacitance in the range of 1 μF cm(-2) in full accumulation and a mobility-capacitance product of 7 × 10(-3) μF/V s. Short-term stability measurements indicate promising cycling robustness, despite operating the device in an environment typically considered harsh, especially for electron-transporting organic molecules. This work paves the way toward advanced circuitry design for signal conditioning and actuation in an aqueous environment and opens new perspectives in the implementation of active bio-organic interfaces for biosensing and neuromodulation.

  19. Electric-field control of the band gap and Fermi energy in graphene multilayers by top and back gates

    Science.gov (United States)

    Avetisyan, A. A.; Partoens, B.; Peeters, F. M.

    2009-11-01

    It is known that a perpendicular electric field applied to multilayers of graphene modifies the electronic structure near the K point and may induce an energy gap in the electronic spectrum which is tunable by the gate voltage. Here we consider a system of graphene multilayers in the presence of a positively charged top and a negatively charged back gate to control independently the density of electrons on the graphene layers and the Fermi energy of the system. The band structure of three- and four-layer graphene systems in the presence of the top and back gates is obtained using a tight-binding approach. A self-consistent Hartree approximation is used to calculate the induced charges on the different graphene layers. We predict that for opposite and equal charges on the top and bottom layers an energy gap is opened at the Fermi level. For an even number of layers this gap is larger than in the case of an odd number of graphene layers. We find that the circular asymmetry of the spectrum, which is a consequence of the trigonal warping, changes the size of the induced electronic gap, even when the total density of the induced electrons on the graphene layers is low.

  20. Complementary Metal-Oxide-Silicon Field-Effect-Transistors Featuring Atomically Flat Gate Insulator Film/Silicon Interface

    Science.gov (United States)

    Kuroda, Rihito; Teramoto, Akinobu; Nakao, Yukihisa; Suwa, Tomoyuki; Konda, Masahiro; Hasebe, Rui; Li, Xiang; Isogai, Tatsunori; Tanaka, Hiroaki; Sugawa, Shigetoshi; Ohmi, Tadahiro

    2009-04-01

    In this paper, we demonstrate newly developed process technology to fabricate complementary metal-oxide-silicon field-effect transistors (CMOSFETs) having atomically flat gate insulator film/silicon interface on (100) orientated silicon surface. They include 1,200 °C ultraclean argon ambient annealing technology for surface atomically flattening and radical oxidation technology for device isolation, flatness recovery after ion implantation, and gate insulator formation. The fabricated CMOSFET with atomically flat interface exhibit very high current drivability such as 923 and 538 µA/µm for n-channel MOSFET (nMOS) and p-channel MOSFET (pMOS) at gate length of 100 nm when combined with very low resistance source and drain contacts, four orders of magnitude lower 1/ f noise characteristics when combined with damage free plasma processes, and one decade longer time dependent dielectric breakdown (TDDB) lifetime in comparison to devices with a conventional flatness. The developed technology effectively improves the performance of the silicon-based CMOS large-scale integrated circuits (LSI).

  1. Modelling and Realization of a Water-Gated Field Effect Transistor (WG-FET) Using 16-nm-Thick Mono-Si Film.

    Science.gov (United States)

    Sonmez, Bedri Gurkan; Ertop, Ozan; Mutlu, Senol

    2017-09-22

    We introduced a novel water-gated field effect transistor (WG-FET) which uses 16-nm-thick mono-Si film as active layer. WG-FET devices use electrical double layer (EDL) as gate insulator and operate under 1 V without causing any electrochemical reactions. Performance parameters based on voltage distribution on EDL are extracted and current-voltage relations are modelled. Both probe- and planar-gate WG-FETs with insulated and uninsulated source-drain electrodes are simulated, fabricated and tested. Best on/off ratios are measured for probe-gate devices as 23,000 A/A and 85,000 A/A with insulated and uninsulated source-drain electrodes, respectively. Planar-gate devices with source-drain insulation had inferior on/off ratio of 1,100 A/A with 600 μm gate distance and it decreased to 45 A/A when gate distance is increased to 3000 μm. Without source-drain electrode insulation, proper transistor operation is not obtained with planar-gate devices. All measurement results were in agreement with theoretical models. WG-FET is a promising device platform for microfluidic applications where sensors and read-out circuits can be integrated at transistor level.

  2. Photocurrent spectroscopy of exciton and free particle optical transitions in suspended carbon nanotube pn-junctions

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Shun-Wen [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089 (United States); Theiss, Jesse; Hazra, Jubin; Aykol, Mehmet; Kapadia, Rehan [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Cronin, Stephen B. [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089 (United States); Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Department of Chemistry, University of Southern California, Los Angeles, California 90089 (United States)

    2015-08-03

    We study photocurrent generation in individual, suspended carbon nanotube pn-junction diodes formed by electrostatic doping using two gate electrodes. Photocurrent spectra collected under various electrostatic doping concentrations reveal distinctive behaviors for free particle optical transitions and excitonic transitions. In particular, the photocurrent generated by excitonic transitions exhibits a strong gate doping dependence, while that of the free particle transitions is gate independent. Here, the built-in potential of the pn-junction is required to separate the strongly bound electron-hole pairs of the excitons, while free particle excitations do not require this field-assisted charge separation. We observe a sharp, well defined E{sub 11} free particle interband transition in contrast with previous photocurrent studies. Several steps are taken to ensure that the active charge separating region of these pn-junctions is suspended off the substrate in a suspended region that is substantially longer than the exciton diffusion length and, therefore, the photocurrent does not originate from a Schottky junction. We present a detailed model of the built-in fields in these pn-junctions, which, together with phonon-assistant exciton dissociation, predicts photocurrents on the same order of those observed experimentally.

  3. A universal design of field-effect-tunable microfluidic ion diode based on a gating cation-exchange nanoporous membrane

    Science.gov (United States)

    Liu, Weiyu; Ren, Yukun; Tao, Ye; Yao, Bobin; Liu, Ni; Wu, Qisheng

    2017-11-01

    Based on the continuum mechanics theory, we propose herein a universal design of microfluidic ionic diode based on external concentration polarization of a gating ion-selective medium embedded in the microfluidic network with four power terminals. This micro/nanofluidic hybrid chip employs a cation-exchange nanoporous membrane (CEM) coupled with both a control and output microfluidic channel. Under the action of a vertical electric field throughout the CEM, nanoscale surface conduction of excessive counterions within the charged nanopores is converted to the propagation of either enriched or depleted boundary toward the opposing electrode-terminal in phase with the electroconvective flow, thereby making an adjustment in the electrical conductance of output microchannel for achieving high-flux field-effect current control and diode functionality. Three basic working states, including the "on," "transition," and "off" statuses, are distinguished in different ranges of source voltage magnitude. The rectification factor of the proposed ionic circuit platform can attain one hundred-fold even at small source and gate voltages. The presented field-effect-tunable microfluidic ion diode is easily scalable, permits appreciable fluid flow due to an intrinsically small hydrodynamic resistance, and holds promise for producing high-flux ion current rectification in next-generation integrated circuits.

  4. Investigation of Body Bias Dependence of Gate-Induced Drain Leakage Current for Body-Tied Fin Field Effect Transistor

    Science.gov (United States)

    Yoshida, Makoto; Lee, Chul; Jung, Kyoung-Ho; Kim, Chang-Kyu; Kim, Hui-Jung; Park, Heungsik; Lee, Won-Sok; Kim, Keunnam; Kahng, Jae-Rok; Yang, Wouns; Park, Donggun

    2008-09-01

    The body bias dependence of gate-induced drain leakage (GIDL) current for a fin field effect transistor fabricated on a bulk Si wafer (bulk FinFET) is investigated. The local damascene (LD) bulk FinFET is measured under various bias conditions and the effect of the body-bias-induced lateral electric field on GIDL current is evaluated. A lateral electric field shield effect under fin depleted condition is proposed and it is validated by the three-terminal band-to-band tunneling current model. The GIDL current of the bulk FinFET can be reduced by reducing the body bias, and an improvement in retention characteristics is expected.

  5. New isolated gate bipolar transistor two-quadrant chopper power supply for a fast field cycling nuclear magnetic resonance spectrometer

    Science.gov (United States)

    Sousa, D. M.; Marques, G. D.; Sebastião, P. J.; Ribeiro, A. C.

    2003-10-01

    This work, presents, for the first time, an Isolated Gate Bipolar Transistor (IGBT) two-quadrant chopper power supply for a fast field cycling (FFC) nuclear magnetic resonance spectrometer. This power supply was designed to achieve a maximum current of 200 A with good efficiency, low semiconductor losses, low cost, and easy maintenance. Both energy storage circuits and dumping circuits are used to obtain switching times less than 2 ms between field levels in agreement with the FFC technique specifications. The current ripple at high currents is better than 1×10-4 and presents a specific shape which can be used for additional compensation using auxiliary circuits. The implemented power supply was tested and been continuously operating with a home-built FFC solenoidal magnet, associated cooling system, and rf units for fields between 0 and 0.2 T.

  6. In-situ Raman Spectroscopy of the Graphene / Water Interface of a Solution-Gated Field Effect Transistor: Electron-Phonon Coupling and Spectroelectrochemistry

    OpenAIRE

    Binder, J.; Urban, J. M.; Stepniewski, R.; Strupinski, W.; Wysmolek, A.

    2014-01-01

    We present a novel measurement approach which combines the electrical characterization of solution-gated field effect transistors based on epitaxial bilayer graphene on 4H-SiC (0001) with simultaneous Raman spectroscopy. By changing the gate voltage, we observed Raman signatures related to the resonant electron-phonon coupling. An analysis of these Raman bands enabled the extraction of the geometrical capacitance of the system and an accurate calculation of the Fermi levels for bilayer graphe...

  7. Impact of Gate Poly Depletion on Evaluation of Channel Temperature in Silicon-on-Insulator Metal-Oxide-Semiconductor Field-Effect Transistors with Four-Point Gate Resistance Measurement Method

    Science.gov (United States)

    Beppu, Nobuyasu; Takahashi, Tsunaki; Ohashi, Teruyuki; Uchida, Ken

    2012-02-01

    Self-heating effects (SHEs) in silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) is evaluated and an accurate measurement method for device temperature is developed using the four-point gate resistance measurement method. Although the method of using a polysilicon gate as a temperature sensor was proposed more than 20 years ago, the accuracy of the technique has not been checked. In this work, it is demonstrated that the channel temperature estimated by the conventional method is not accurate under some special conditions. The measurements of gate resistance under various biases revealed that the depletion of the polysilicon gate had a significant impact on gate resistance. We propose a method of accurately evaluating channel temperature, where the effect of poly depletion is successfully subtracted. At an input power of 5 mW the increase in channel temperature is approximately 30 K, corresponding to a thermal resistance of 6.0 K W-1 m-1.

  8. Human dopamine receptor nanovesicles for gate-potential modulators in high-performance field-effect transistor biosensors

    Science.gov (United States)

    Park, Seon Joo; Song, Hyun Seok; Kwon, Oh Seok; Chung, Ji Hyun; Lee, Seung Hwan; An, Ji Hyun; Ahn, Sae Ryun; Lee, Ji Eun; Yoon, Hyeonseok; Park, Tai Hyun; Jang, Jyongsik

    2014-03-01

    The development of molecular detection that allows rapid responses with high sensitivity and selectivity remains challenging. Herein, we demonstrate the strategy of novel bio-nanotechnology to successfully fabricate high-performance dopamine (DA) biosensor using DA Receptor-containing uniform-particle-shaped Nanovesicles-immobilized Carboxylated poly(3,4-ethylenedioxythiophene) (CPEDOT) NTs (DRNCNs). DA molecules are commonly associated with serious diseases, such as Parkinson's and Alzheimer's diseases. For the first time, nanovesicles containing a human DA receptor D1 (hDRD1) were successfully constructed from HEK-293 cells, stably expressing hDRD1. The nanovesicles containing hDRD1 as gate-potential modulator on the conducting polymer (CP) nanomaterial transistors provided high-performance responses to DA molecule owing to their uniform, monodispersive morphologies and outstanding discrimination ability. Specifically, the DRNCNs were integrated into a liquid-ion gated field-effect transistor (FET) system via immobilization and attachment processes, leading to high sensitivity and excellent selectivity toward DA in liquid state. Unprecedentedly, the minimum detectable level (MDL) from the field-induced DA responses was as low as 10 pM in real- time, which is 10 times more sensitive than that of previously reported CP based-DA biosensors. Moreover, the FET-type DRNCN biosensor had a rapid response time (<1 s) and showed excellent selectivity in human serum.

  9. A field-programmable gate array based system for high frame rate laser Doppler blood flow imaging.

    Science.gov (United States)

    Nguyen, H C; Hayes-Gill, B R; Morgan, S P; Zhu, Y; Boggett, D; Huang, X; Potter, M

    2010-01-01

    This paper presents a general embedded processing system implemented in a field-programmable gate array providing high frame rate and high accuracy for a laser Doppler blood flow imaging system. The proposed system can achieve a basic frame rate of flow images at 1 frame/second for 256 x 256 images with 1024 fast Fourier transform (FFT) points used in the processing algorithm. Mixed fixed-floating point calculations are utilized to achieve high accuracy but with a reasonable resource usage. The implementation has a root mean square deviation of the relative difference in flow values below 0.1% when compared with a double-precision floating point implementation. The system can contain from one or more processing units to obtain the required frame rate and accuracy. The performance of the system is significantly higher than other methods reported to date. Furthermore, a dedicated field-programmable gate array (FPGA) board has been designed to test the proposed processing system. The board is linked with a laser line scanning system, which uses a 64 x 1 photodetector array. Test results with various operating parameters show that the performance of the new system is better, in terms of noise and imaging speed, than has been previously achieved.

  10. Development of Gate and Base Drive Using SiC Junction Field Effect Transistors

    Science.gov (United States)

    2008-05-01

    junction transistor ( BJT ). The circuit rapidly drove a SiC BJT on and off with 4H-SiC semiconductor devices to perform to 150 °C. For the gate of an n...Figures iv List of Tables iv SiC Power Transistors : Focus on JFETs 1 JFET Background 1 JFETs Used, and Circuit Using Normally-Off JFET to Drive BJT On...induction transistors . JFET Background JFET and MOS have unipolar conduction without conductivity modulation by injected minority carriers as for BJT

  11. Linearity study of multiple independent gate field effect transistor (MIGFET) under symmetric and asymmetric operations

    Science.gov (United States)

    Gong, Jing-Feng; Chan, Philip C. H.

    2008-02-01

    In this paper, we investigate the linearity of undoped body multi-gate independent FinFET (MIGFET) experimentally. The MIGFET device with sub-50 nm body thickness is fabricated on SOI wafers. The device transconductance and its high order derivatives under different bias conditions are measured. RF two-tone inter-modulation distortion measurements are performed. Both the DC and RF measurements demonstrate that the properly biased asymmetric MIGFET provides better linearity performance than that of symmetric MIGFET biased at the conventional moderate inversion linearity "sweet spot". The improved linearity is explained.

  12. High Sensitivity pH Sensor Based on Porous Silicon (PSi Extended Gate Field-Effect Transistor

    Directory of Open Access Journals (Sweden)

    Naif H. Al-Hardan

    2016-06-01

    Full Text Available In this study, porous silicon (PSi was prepared and tested as an extended gate field-effect transistor (EGFET for pH sensing. The prepared PSi has pore sizes in the range of 500 to 750 nm with a depth of approximately 42 µm. The results of testing PSi for hydrogen ion sensing in different pH buffer solutions reveal that the PSi has a sensitivity value of 66 mV/pH that is considered a super Nernstian value. The sensor considers stability to be in the pH range of 2 to 12. The hysteresis values of the prepared PSi sensor were approximately 8.2 and 10.5 mV in the low and high pH loop, respectively. The result of this study reveals a promising application of PSi in the field for detecting hydrogen ions in different solutions.

  13. Note: A high-frequency signal generator based on direct digital synthesizer and field-programmable gate array

    Science.gov (United States)

    Du, Yuanbo; Li, Wenbing; Ge, Yapeng; Li, Hui; Deng, Ke; Lu, Zehuang

    2017-09-01

    A high-frequency signal generator based on direct digital synthesizer (DDS) and field-programmable gate array (FPGA) is presented. The FPGA provides the controlling time sequence for the DDS, which has a highest output frequency of 1.4 GHz and a frequency resolution of 190 pHz. At an output frequency of 1.2 GHz, the measured phase noise, including the contribution of the reference clock, is -65 dBc/Hz@1 Hz, while the intrinsic phase noise is -82 dBc/Hz@1 Hz. Time delay of the DDS is measured to be less than 150 ns. The signal generator is used to drive an acousto-optic modulator, and the rise time due to the whole link is 24 ns. The developed signal generator can be used in many precision measurement experiments in the fields of atomic, molecular, and optical physics.

  14. High Sensitivity pH Sensor Based on Porous Silicon (PSi) Extended Gate Field-Effect Transistor.

    Science.gov (United States)

    Al-Hardan, Naif H; Abdul Hamid, Muhammad Azmi; Ahmed, Naser M; Jalar, Azman; Shamsudin, Roslinda; Othman, Norinsan Kamil; Kar Keng, Lim; Chiu, Weesiong; Al-Rawi, Hamzah N

    2016-06-07

    In this study, porous silicon (PSi) was prepared and tested as an extended gate field-effect transistor (EGFET) for pH sensing. The prepared PSi has pore sizes in the range of 500 to 750 nm with a depth of approximately 42 µm. The results of testing PSi for hydrogen ion sensing in different pH buffer solutions reveal that the PSi has a sensitivity value of 66 mV/pH that is considered a super Nernstian value. The sensor considers stability to be in the pH range of 2 to 12. The hysteresis values of the prepared PSi sensor were approximately 8.2 and 10.5 mV in the low and high pH loop, respectively. The result of this study reveals a promising application of PSi in the field for detecting hydrogen ions in different solutions.

  15. Suspended microfluidics

    National Research Council Canada - National Science Library

    Benjamin P. Casavant; Erwin Berthier; Ashleigh B. Theberge; Jean Berthier; Sara I. Montanez-Sauri; Lauren L. Bischel; Kenneth Brakke; Curtis J. Hedman; Wade Bushman; Nancy P. Keller; David J. Beebe

    2013-01-01

    Although the field of microfluidics has made significant progress in bringing new tools to address biological questions, the accessibility and adoption of microfluidics within the life sciences are still limited...

  16. Electrical performance and low frequency noise in hexagonal boron nitride encapsulated MoSe2 dual-gated field effect transistors

    Science.gov (United States)

    Liao, Wugang; Wei, Wei; Tong, Yu; Chim, Wai Kin; Zhu, Chunxiang

    2017-08-01

    We demonstrate few-layer molybdenum diselenide (MoSe2) dual-gated field effect transistors (FETs) with few-layer hexagonal boron nitride (hBN) flakes as encapsulation and multilayer graphene as electrical contacts. A high current on/off ratio of up to ˜108, a two-terminal electron mobility of 38.5 cm2/V.s at room temperature, and negligible hysteresis are achieved in hBN encapsulated MoSe2 FETs. Our results also indicate that the flicker (1/f) current noise in hBN encapsulated MoSe2 transistors is governed by Hooge's carrier mobility fluctuation and the normalized current noise in the dual-gated configuration can be dramatically reduced by applying a positive bias on the bottom gate. All these suggest that dual-gated MoSe2 FETs are very promising candidates for sensing applications.

  17. New Analytical Model for Short-Channel Fully Depleted Dual-Material-Gate Silicon-on-Insulator Metal-Oxide-Semiconductor Field-Effect Transistors

    Science.gov (United States)

    Te-Kuang Chiang,

    2010-07-01

    Using the exact solution of the two-dimensional Poisson equation, a new analytical model comprising two-dimensional potential and threshold voltage for short-channel fully depleted dual-material-gate silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) is developed. The model shows that the minimum acceptable channel length can be sustained while repressing the short-channel effects if a thin gate oxide and a thin silicon body are employed in the device. Moreover, by increasing the ratio of the screen gate length to control gate length, the threshold voltage roll-off can be more effectively reduced. The model is verified by the close agreement of its results with those of a numerical simulation using the device simulator MEDICI. The model not only offers an insight into the device physics but is also an efficient model for circuit simulation.

  18. Irradiation effect on back-gate graphene field-effect transistor

    Science.gov (United States)

    Chen, Xinlu; Srivastava, Ashok; Sharma, Ashwani K.; Mayberry, Clay

    2017-05-01

    The effects of irradiations on MOSFET and bipolar junction transistors are well known though irradiation mechanisms in two-dimensional graphene and related devices are still being investigated. In this work, we investigate irradiation mechanism based on a semi-empirical model for the graphene back-gate transistor and quantitatively analyze the irradiation influences on electrical properties of the device structure. The irradiation shifts the current which changes the region of device operation, degrades the mobility and increases the channel resistance which can increase the power dissipation. The main mechanism causing the degradation in performance of devices is the oxide trap charges near the SiO2/graphene interface and graphene layer traps charges.

  19. pH sensing characteristics and biosensing application of solution-gated reduced graphene oxide field-effect transistors.

    Science.gov (United States)

    Sohn, Il-Yung; Kim, Duck-Jin; Jung, Jin-Heak; Yoon, Ok Ja; Thanh, Tien Nguyen; Quang, Trung Tran; Lee, Nae-Eung

    2013-07-15

    Solution-gated reduced graphene oxide field-effect transistors (R-GO FETs) were investigated for pH sensing and biochemical sensing applications. A channel of a networked R-GO film formed by self-assembly was incorporated as a sensing layer into a solution-gated FET structure for pH sensing and the detection of acetylcholine (Ach), which is a neurotransmitter in the nerve system, through enzymatic reactions. The fabricated R-GO FET was sensitive to protons (H(+)) with a pH sensitivity of 29 mV/pH in terms of the shift of the charge neutrality point (CNP), which is attributed to changes in the surface potential caused by the interaction of protons with OH surface functional groups present on the R-GO surface. The R-GO FET immobilized with acetylcholinesterase (AchE) was used to detect Ach in the concentration range of 0.1-10mM by sensing protons generated during the enzymatic reactions. The results indicate that R-GO FETs provide the capability to detect protons, demonstrating their applicability as a biosensing device for enzymatic reactions. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Evaluation of the Leon3 soft-core processor within a Xilinx radiation-hardened field-programmable gate array.

    Energy Technology Data Exchange (ETDEWEB)

    Learn, Mark Walter

    2012-01-01

    The purpose of this document is to summarize the work done to evaluate the performance of the Leon3 soft-core processor in a radiation environment while instantiated in a radiation-hardened static random-access memory based field-programmable gate array. This evaluation will look at the differences between two soft-core processors: the open-source Leon3 core and the fault-tolerant Leon3 core. Radiation testing of these two cores was conducted at the Texas A&M University Cyclotron facility and Lawrence Berkeley National Laboratory. The results of these tests are included within the report along with designs intended to improve the mitigation of the open-source Leon3. The test setup used for evaluating both versions of the Leon3 is also included within this document.

  1. Effects of drain bias on the statistical variation of double-gate tunnel field-effect transistors

    Science.gov (United States)

    Choi, Woo Young

    2017-04-01

    The effects of drain bias on the statistical variation of double-gate (DG) tunnel field-effect transistors (TFETs) are discussed in comparison with DG metal-oxide-semiconductor FETs (MOSFETs). Statistical variation corresponds to the variation of threshold voltage (V th), subthreshold swing (SS), and drain-induced barrier thinning (DIBT). The unique statistical variation characteristics of DG TFETs and DG MOSFETs with the variation of drain bias are analyzed by using full three-dimensional technology computer-aided design (TCAD) simulation in terms of the three dominant variation sources: line-edge roughness (LER), random dopant fluctuation (RDF) and workfunction variation (WFV). It is observed than DG TFETs suffer from less severe statistical variation as drain voltage increases unlike DG MOSFETs.

  2. A flexible 32-channel time-to-digital converter implemented in a Xilinx Zynq-7000 field programmable gate array

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yonggang, E-mail: wangyg@ustc.edu.cn; Kuang, Jie; Liu, Chong; Cao, Qiang; Li, Deng

    2017-03-01

    A high performance multi-channel time-to-digital converter (TDC) is implemented in a Xilinx Zynq-7000 field programmable gate array (FPGA). It can be flexibly configured as either 32 TDC channels with 9.9 ps time-interval RMS precision, 16 TDC channels with 6.9 ps RMS precision, or 8 TDC channels with 5.8 ps RMS precision. All TDCs have a 380 M Samples/second measurement throughput and a 2.63 ns measurement dead time. The performance consistency and temperature dependence of TDC channels are also evaluated. Because Zynq-7000 FPGA family integrates a feature-rich dual-core ARM based processing system and 28 nm Xilinx programmable logic in a single device, the realization of high performance TDCs on it will make the platform more widely used in time-measuring related applications.

  3. Compact model of ferroelectric-gate field-effect transistor for circuit simulation based on multidomain Landau-Kalathnikov theory

    Science.gov (United States)

    Asai, Hidehiro; Fukuda, Koichi; Hattori, Junichi; Koike, Hanpei; Miyata, Noriyuki; Takahashi, Mitsue; Sakai, Shigeki

    2017-04-01

    We report a new compact model for a ferroelectric-gate field-effect transistor (FeFET) considering multiple ferroelectric domain structures that can be thermally activated. The dynamics of the electric polarization and the thermal activation rate are calculated on the basis of the Landau-Khalatnikov (LK) theory. We implement this compact model in a circuit simulator, SmartSPICE, using Verilog-A language for analog circuit simulations. The device characteristics of FeFETs reported in experiments are well fitted by our compact model. We also perform the circuit simulation for the inverter utilizing FeFETs by using this compact model. Unlike normal inverters composed of MOSFETs, the switching speed of the inverter changes with the voltage pulse before the operation.

  4. Implementation of a high resolution (< 11 ps RMS) Time-to-Digital Converter in a Field Programmable Gate Array

    Energy Technology Data Exchange (ETDEWEB)

    Ugur, Cahit [Helmholtz-Institut Mainz, Johannes Gutenberg-Universitaet Mainz (Germany); Bayer, Eugen [Department for Digital Electronics, University Kassel (Germany); Kurz, Nikolaus; Traxler, Michael [GSI Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany); Michel, Jan [Institute for Nuclear Physics, Goethe University Frankfurt, Frankfurt am Main (Germany)

    2012-07-01

    A high resolution time-to-digital converter (TDC) was implemented in a general purpose field-programmable gate array (FPGA), a re-programmable digital chip. RMS and the time resolution of different channels are calculated for one clock cycle (5 ns) interval and a minimum of 10.3 ps RMS on two channels is achieved, which yields to a time resolution of 7.3 ps (10.3 ps/{radical}(2)) on a single channel. The TDC can be used in time-of-flight, time-over-threshold, drift time measurement applications as well as many other measurements with specific Front-End Electronics (FEE), e.g. charge measurements with charge-to-width (Q2W) FEE. The re-programmable flexibility of FPGAs also allows to have application specific features, e.g. trigger window, zero dead time etc.

  5. Real-time processing of fast-scan cyclic voltammetry (FSCV) data using a field-programmable gate array (FPGA).

    Science.gov (United States)

    Bozorgzadeh, Bardia; Covey, Daniel P; Heidenreich, Byron A; Garris, Paul A; Mohseni, Pedram

    2014-01-01

    This paper reports the hardware implementation of a digital signal processing (DSP) unit for real-time processing of data obtained by fast-scan cyclic voltammetry (FSCV) at a carbon-fiber microelectrode (CFM), an electrochemical transduction technique for high-resolution monitoring of brain neurochemistry. Implemented on a field-programmable gate array (FPGA), the DSP unit comprises a decimation filter and an embedded processor to process the oversampled FSCV data and obtain in real time a temporal profile of concentration variation along with a chemical signature to identify the target neurotransmitter. Interfaced with an integrated, FSCV-sensing front-end, the DSP unit can successfully process FSCV data obtained by bolus injection of dopamine in a flow cell as well as electrically evoked, transient dopamine release in the dorsal striatum of an anesthetized rat.

  6. Gate Tunable Transport in Graphene/MoS2/(Cr/Au Vertical Field-Effect Transistors

    Directory of Open Access Journals (Sweden)

    Ghazanfar Nazir

    2017-12-01

    Full Text Available Two-dimensional materials based vertical field-effect transistors have been widely studied due to their useful applications in industry. In the present study, we fabricate graphene/MoS2/(Cr/Au vertical transistor based on the mechanical exfoliation and dry transfer method. Since the bottom electrode was made of monolayer graphene (Gr, the electrical transport in our Gr/MoS2/(Cr/Au vertical transistors can be significantly modified by using back-gate voltage. Schottky barrier height at the interface between Gr and MoS2 can be modified by back-gate voltage and the current bias. Vertical resistance (Rvert of a Gr/MoS2/(Cr/Au transistor is compared with planar resistance (Rplanar of a conventional lateral MoS2 field-effect transistor. We have also studied electrical properties for various thicknesses of MoS2 channels in both vertical and lateral transistors. As the thickness of MoS2 increases, Rvert increases, but Rplanar decreases. The increase of Rvert in the thicker MoS2 film is attributed to the interlayer resistance in the vertical direction. However, Rplanar shows a lower value for a thicker MoS2 film because of an excess of charge carriers available in upper layers connected directly to source/drain contacts that limits the conduction through layers closed to source/drain electrodes. Hence, interlayer resistance associated with these layers contributes to planer resistance in contrast to vertical devices in which all layers contribute interlayer resistance.

  7. Extended-gate field-effect transistor (EG-FET) with molecularly imprinted polymer (MIP) film for selective inosine determination.

    Science.gov (United States)

    Iskierko, Zofia; Sosnowska, Marta; Sharma, Piyush Sindhu; Benincori, Tiziana; D'Souza, Francis; Kaminska, Izabela; Fronc, Krzysztof; Noworyta, Krzysztof

    2015-12-15

    A novel recognition unit of chemical sensor for selective determination of the inosine, renal disfunction biomarker, was devised and prepared. For that purpose, inosine-templated molecularly imprinted polymer (MIP) film was deposited on an extended-gate field-effect transistor (EG-FET) signal transducing unit. The MIP film was prepared by electrochemical polymerization of bis(bithiophene) derivatives bearing cytosine and boronic acid substituents, in the presence of the inosine template and a thiophene cross-linker. After MIP film deposition, the template was removed, and was confirmed by UV-visible spectroscopy. Subsequently, the film composition was characterized by spectroscopic techniques, and its morphology and thickness were determined by AFM. The finally MIP film-coated extended-gate field-effect transistor (EG-FET) was used for signal transduction. This combination is not widely studied in the literature, despite the fact that it allows for facile integration of electrodeposited MIP film with FET transducer. The linear dynamic concentration range of the chemosensor was 0.5-50 μM with inosine detectability of 0.62 μM. The obtained detectability compares well to the levels of the inosine in body fluids which are in the range 0-2.9 µM for patients with diagnosed diabetic nephropathy, gout or hyperuricemia, and can reach 25 µM in certain cases. The imprinting factor for inosine, determined from piezomicrogravimetric experiments with use of the MIP film-coated quartz crystal resonator, was found to be 5.5. Higher selectivity for inosine with respect to common interferents was also achieved with the present molecularly engineered sensing element. The obtained analytical parameters of the devised chemosensor allow for its use for practical sample measurements. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Silicon nanotube field effect transistor with core-shell gate stacks for enhanced high-performance operation and area scaling benefits

    KAUST Repository

    Fahad, Hossain M.

    2011-10-12

    We introduce the concept of a silicon nanotube field effect transistor whose unique core-shell gate stacks help achieve full volume inversion by giving a surge in minority carrier concentration in the near vicinity of the ultrathin channel and at the same time rapid roll-off at the source and drain junctions constituting velocity saturation-induced higher drive current-enhanced high performance per device with efficient real estate consumption. The core-shell gate stacks also provide superior short channel effects control than classical planar metal oxide semiconductor field effect transistor (MOSFET) and gate-all-around nanowire FET. The proposed device offers the true potential to be an ideal blend for quantum ballistic transport study of device property control by bottom-up approach and high-density integration compatibility using top-down state-of-the-art complementary metal oxide semiconductor flow. © 2011 American Chemical Society.

  9. Top-gated field-effect LaAlO{sub 3}/SrTiO{sub 3} devices made by ion-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Hurand, S.; Jouan, A.; Feuillet-Palma, C.; Singh, G.; Malnou, M.; Lesueur, J.; Bergeal, N. [Laboratoire de Physique et d' Etude des Matériaux-CNRS-ESPCI ParisTech-UPMC, PSL Research University, 10 Rue Vauquelin - 75005 Paris (France); Lesne, E.; Reyren, N.; Barthélémy, A.; Bibes, M.; Villegas, J. E. [Unité Mixte de Physique CNRS-Thales, 1 Av. A. Fresnel, 91767 Palaiseau (France); Ulysse, C. [Laboratoire de Photonique et de Nanostructures LPN-CNRS, Route de Nozay, 91460 Marcoussis and Universit Paris Sud, 91405 Orsay (France); Pannetier-Lecoeur, M. [DSM/IRAMIS/SPEC - CNRS UMR 3680, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France)

    2016-02-01

    We present a method to fabricate top-gated field-effect devices in a LaAlO{sub 3}/SrTiO{sub 3} two-dimensional electron gas (2-DEG). Prior to the gate deposition, the realisation of micron size conducting channels in the 2-DEG is achieved by an ion-irradiation with high-energy oxygen ions. After identifying the ion fluence as the key parameter that determines the electrical transport properties of the channels, we demonstrate the field-effect operation. At low temperature, the normal state resistance and the superconducting T{sub c} can be tuned over a wide range by a top-gate voltage without any leakage. A superconductor-to-insulator quantum phase transition is observed for a strong depletion of the 2-DEG.

  10. Characteristics enhancement of a GaAs based heterostructure field-effect transistor with an electrophoretic deposition (EPD) surface treated gate structure

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chun-Chia [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, No. 1, University Road, Tainan 70101, Taiwan, ROC (China); Chen, Huey-Ing; Liu, I-Ping [Department of Chemical Engineering, National Cheng-Kung University, No. 1, University Road, Tainan 70101, Taiwan, ROC (China); Chou, Po-Cheng; Liou, Jian-Kai; Tsai, Yu-Ting [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, No. 1, University Road, Tainan 70101, Taiwan, ROC (China); Liu, Wen-Chau, E-mail: wcliu@mail.ncku.edu.tw [Institute of Microelectronics, Department of Electrical Engineering, National Cheng-Kung University, No. 1, University Road, Tainan 70101, Taiwan, ROC (China)

    2015-06-30

    Highlights: • Platinum (Pt) was formed on the gate region of a heterostructure field-effect transistor (HFET) by an electrophoretic deposition (EPD) approach. • EPD-based Pt morphologies were examined by SEM, AFM, XRD, and EDS analyses. • EPD approach shows advantages of low cost, simple apparatus, and adjustable alloy grain size. • EPD-based Pt-gate structure contributes to device's superior temperature-dependent I–V characteristics. - Abstract: A Pt/AlGaAs/InGaAs/GaAs heterostructure field-effect transistor (HFET), prepared by an electrophoretic deposition (EPD) approach on gate Schottky contact region, is fabricated and studied. The EPD-based Pt-gates with three different molar ratios (ω{sub 0}) are examined by scanning electron microscopy (SEM) image. Good Pt-gate coverage with effective reduction of thermal-induced defects at Pt/AlGaAs interface is achieved through a low temperature EPD approach. Experimentally, for a gate dimension of 1 μm × 100 μm, a lower gate current of 1.9 × 10{sup −2} mA/mm, a higher turn-on voltage of 0.85 V, a higher maximum drain saturation current of 319.3 mA/mm, and a higher maximum extrinsic transconductance of 146.8 mS/mm are obtained for an EPD-based HFET at 300 K. Moreover, comparable microwave characteristics of an EPD-based HFET are demonstrated at different temperature ambiences. Therefore, based on the improved DC performance and inherent benefits of low cost, simple apparatus, flexible deposition on varied substrates, and adjustable alloy grain size, the proposed EPD approach shows the promise to fabricate high-performance electronic devices.

  11. Improving pH sensitivity by field-induced charge regulation in flexible biopolymer electrolyte gated oxide transistors

    Science.gov (United States)

    Liu, Ning; Gan, Lu; Liu, Yu; Gui, Weijun; Li, Wei; Zhang, Xiaohang

    2017-10-01

    Electrical manipulation of charged ions in electrolyte-gated transistors is crucial for enhancing the electric-double-layer (EDL) gating effect, thereby improving their sensing abilities. Here, indium-zinc-oxide (IZO) based thin-film-transistors (TFTs) are fabricated on flexible plastic substrate. Acid doped chitosan-based biopolymer electrolyte is used as the gate dielectric, exhibiting an extremely high EDL capacitance. By regulating the dynamic EDL charging process with special gate potential profiles, the EDL gating effect of the chitosan-gated TFT is enhanced, and then resulting in higher pH sensitivities. An extremely high sensitivity of ∼57.8 mV/pH close to Nernst limit is achieved when the gate bias of the TFT sensor sweeps at a rate of 10 mV/s. Additionally, an enhanced sensitivity of 2630% in terms of current variation with pH range from 11 to 3 is realized when the device is operated in the ion depletion mode with a negative gate bias of -0.7 V. Robust ionic modulation is demonstrated in such chitosan-gated sensors. Efficiently driving the charged ions in the chitosan-gated IZO-TFT provides a new route for ultrasensitive, low voltage, and low-cost biochemical sensing technologies.

  12. Single Event Analysis and Fault Injection Techniques Targeting Complex Designs Implemented in Xilinx-Virtex Family Field Programmable Gate Array (FPGA) Devices

    Science.gov (United States)

    Berg, Melanie D.; LaBel, Kenneth; Kim, Hak

    2014-01-01

    An informative session regarding SRAM FPGA basics. Presenting a framework for fault injection techniques applied to Xilinx Field Programmable Gate Arrays (FPGAs). Introduce an overlooked time component that illustrates fault injection is impractical for most real designs as a stand-alone characterization tool. Demonstrate procedures that benefit from fault injection error analysis.

  13. Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects.

    Science.gov (United States)

    Pall, Martin L

    2013-08-01

    The direct targets of extremely low and microwave frequency range electromagnetic fields (EMFs) in producing non-thermal effects have not been clearly established. However, studies in the literature, reviewed here, provide substantial support for such direct targets. Twenty-three studies have shown that voltage-gated calcium channels (VGCCs) produce these and other EMF effects, such that the L-type or other VGCC blockers block or greatly lower diverse EMF effects. Furthermore, the voltage-gated properties of these channels may provide biophysically plausible mechanisms for EMF biological effects. Downstream responses of such EMF exposures may be mediated through Ca(2+) /calmodulin stimulation of nitric oxide synthesis. Potentially, physiological/therapeutic responses may be largely as a result of nitric oxide-cGMP-protein kinase G pathway stimulation. A well-studied example of such an apparent therapeutic response, EMF stimulation of bone growth, appears to work along this pathway. However, pathophysiological responses to EMFs may be as a result of nitric oxide-peroxynitrite-oxidative stress pathway of action. A single such well-documented example, EMF induction of DNA single-strand breaks in cells, as measured by alkaline comet assays, is reviewed here. Such single-strand breaks are known to be produced through the action of this pathway. Data on the mechanism of EMF induction of such breaks are limited; what data are available support this proposed mechanism. Other Ca(2+) -mediated regulatory changes, independent of nitric oxide, may also have roles. This article reviews, then, a substantially supported set of targets, VGCCs, whose stimulation produces non-thermal EMF responses by humans/higher animals with downstream effects involving Ca(2+) /calmodulin-dependent nitric oxide increases, which may explain therapeutic and pathophysiological effects. © 2013 The Author. Journal of Cellular and Molecular Medicine Published by Foundation for Cellular and Molecular

  14. Signal-to-noise characterization of time-gated intensifiers used for wide-field time-domain FLIM

    Energy Technology Data Exchange (ETDEWEB)

    McGinty, J; Requejo-Isidro, J; Munro, I; Talbot, C B; Dunsby, C; Neil, M A A; French, P M W [Photonics Group, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2BW (United Kingdom); Kellett, P A; Hares, J D, E-mail: james.mcginty@imperial.ac.u [Kentech Instruments Ltd, Isis Building, Howbery Park, Wallingford, OX10 8BA (United Kingdom)

    2009-07-07

    Time-gated imaging using gated optical intensifiers provides a means to realize high speed fluorescence lifetime imaging (FLIM) for the study of fast events and for high throughput imaging. We present a signal-to-noise characterization of CCD-coupled micro-channel plate gated intensifiers used with this technique and determine the optimal acquisition parameters (intensifier gain voltage, CCD integration time and frame averaging) for measuring mono-exponential fluorescence lifetimes in the shortest image acquisition time for a given signal flux. We explore the use of unequal CCD integration times for different gate delays and show that this can improve the lifetime accuracy for a given total acquisition time.

  15. Two Dimensional Modeling of III-V Heterojunction Gate All Around Tunnel Field Effect Transistor

    OpenAIRE

    Manjula Vijh; R.S. Gupta; Sujata Pandey

    2017-01-01

    Tunnel Field Effect Transistor is one of the extensively researched semiconductor devices, which has captured attention over the conventional Metal Oxide Semiconductor Field Effect Transistor. This device, due to its varied advantages, is considered in applications where devices are scaled down to deep sub-micron level. Like MOSFETs, many geometries of TFETs have been studied and analyzed in the past few years. This work, presents a two dimensional analytical model for a III-V Heterojunction ...

  16. Moderate-intensity rotating magnetic fields do not affect bone quality and bone remodeling in hindlimb suspended rats.

    Directory of Open Access Journals (Sweden)

    Da Jing

    Full Text Available Abundant evidence has substantiated the positive effects of pulsed electromagnetic fields (PEMF and static magnetic fields (SMF on inhibiting osteopenia and promoting fracture healing. However, the osteogenic potential of rotating magnetic fields (RMF, another common electromagnetic application modality, remains poorly characterized thus far, although numerous commercial RMF treatment devices have been available on the market. Herein the impacts of RMF on osteoporotic bone microarchitecture, bone strength and bone metabolism were systematically investigated in hindlimb-unloaded (HU rats. Thirty two 3-month-old male Sprague-Dawley rats were randomly assigned to the Control (n = 10, HU (n = 10 and HU with RMF exposure (HU+RMF, n = 12 groups. Rats in the HU+RMF group were subjected to daily 2-hour exposure to moderate-intensity RMF (ranging from 0.60 T to 0.38 T at 7 Hz for 4 weeks. HU caused significant decreases in body mass and soleus muscle mass of rats, which were not obviously altered by RMF. Three-point bending test showed that the mechanical properties of femurs in HU rats, including maximum load, stiffness, energy absorption and elastic modulus were not markedly affected by RMF. µCT analysis demonstrated that 4-week RMF did not significantly prevent HU-induced deterioration of femoral trabecular and cortical bone microarchitecture. Serum biochemical analysis showed that RMF did not significantly change HU-induced decrease in serum bone formation markers and increase in bone resorption markers. Bone histomorphometric analysis further confirmed that RMF showed no impacts on bone remodeling in HU rats, as evidenced by unchanged mineral apposition rate, bone formation rate, osteoblast numbers and osteoclast numbers in cancellous bone. Together, our findings reveal that RMF do not significantly affect bone microstructure, bone mechanical strength and bone remodeling in HU-induced disuse osteoporotic rats. Our study indicates

  17. Moderate-intensity rotating magnetic fields do not affect bone quality and bone remodeling in hindlimb suspended rats.

    Science.gov (United States)

    Jing, Da; Cai, Jing; Wu, Yan; Shen, Guanghao; Zhai, Mingming; Tong, Shichao; Xu, Qiaoling; Xie, Kangning; Wu, Xiaoming; Tang, Chi; Xu, Xinmin; Liu, Juan; Guo, Wei; Jiang, Maogang; Luo, Erping

    2014-01-01

    Abundant evidence has substantiated the positive effects of pulsed electromagnetic fields (PEMF) and static magnetic fields (SMF) on inhibiting osteopenia and promoting fracture healing. However, the osteogenic potential of rotating magnetic fields (RMF), another common electromagnetic application modality, remains poorly characterized thus far, although numerous commercial RMF treatment devices have been available on the market. Herein the impacts of RMF on osteoporotic bone microarchitecture, bone strength and bone metabolism were systematically investigated in hindlimb-unloaded (HU) rats. Thirty two 3-month-old male Sprague-Dawley rats were randomly assigned to the Control (n = 10), HU (n = 10) and HU with RMF exposure (HU+RMF, n = 12) groups. Rats in the HU+RMF group were subjected to daily 2-hour exposure to moderate-intensity RMF (ranging from 0.60 T to 0.38 T) at 7 Hz for 4 weeks. HU caused significant decreases in body mass and soleus muscle mass of rats, which were not obviously altered by RMF. Three-point bending test showed that the mechanical properties of femurs in HU rats, including maximum load, stiffness, energy absorption and elastic modulus were not markedly affected by RMF. µCT analysis demonstrated that 4-week RMF did not significantly prevent HU-induced deterioration of femoral trabecular and cortical bone microarchitecture. Serum biochemical analysis showed that RMF did not significantly change HU-induced decrease in serum bone formation markers and increase in bone resorption markers. Bone histomorphometric analysis further confirmed that RMF showed no impacts on bone remodeling in HU rats, as evidenced by unchanged mineral apposition rate, bone formation rate, osteoblast numbers and osteoclast numbers in cancellous bone. Together, our findings reveal that RMF do not significantly affect bone microstructure, bone mechanical strength and bone remodeling in HU-induced disuse osteoporotic rats. Our study indicates potentially

  18. Experimental Comparisons between Tetrakis(dimethylamino)titanium Precursor-Based Atomic-Layer-Deposited and Physical-Vapor-Deposited Titanium-Nitride Gate for High-Performance Fin-Type Metal-Oxide-Semiconductor Field-Effect Transistors

    Science.gov (United States)

    Hayashida, Tetsuro; Endo, Kazuhiko; Liu, Yongxun; O'uchi, Shin-ichi; Matsukawa, Takashi; Mizubayashi, Wataru; Migita, Shinji; Morita, Yukinori; Ota, Hiroyuki; Hashiguchi, Hiroki; Kosemura, Daisuke; Kamei, Takahiro; Tsukada, Junichi; Ishikawa, Yuki; Yamauchi, Hiromi; Ogura, Atsushi; Masahara, Meishoku

    2012-04-01

    In this study, we successfully introduced an atomic-layer-deposited (ALD) titanium nitride (TiN) gate grown with a tetrakis(dimethylamino)titanium (TDMAT) precursor into fin-type metal-oxide-semiconductor field-effect transistor (FinFET) fabrication for the first time, and comparatively investigated the electrical characteristics, including mobility and threshold voltage (Vth) variation, of the fabricated ALD and physical-vapor-deposited (PVD)-TiN gate FinFETs. The ALD-TiN gate FinFETs showed superior conformality to the PVD-TiN gate FinFETs. The electron mobilities of the ALD- and PVD-TiN gate FinFETs were comparable in the small Lg region. It was also confirmed that the ALD-TiN gate FinFETs showed a smaller Vth variation than the PVD-TiN gate FinFETs.

  19. Mathematical Models of the Common-Source and Common-Gate Amplifiers using a Metal-Ferroelectric-Semiconductor Field effect Transistor

    Science.gov (United States)

    Hunt, Mitchell; Sayyah, Rana; Mitchell, Cody; Laws, Crystal; MacLeod, Todd C.; Ho, Fat D.

    2013-01-01

    Mathematical models of the common-source and common-gate amplifiers using metal-ferroelectric- semiconductor field effect transistors (MOSFETs) are developed in this paper. The models are compared against data collected with MOSFETs of varying channel lengths and widths, and circuit parameters such as biasing conditions are varied as well. Considerations are made for the capacitance formed by the ferroelectric layer present between the gate and substrate of the transistors. Comparisons between the modeled and measured data are presented in depth as well as differences and advantages as compared to the performance of each circuit using a MOSFET.

  20. Polycrystalline Boron-doped Diamond Electrolyte-solution-gate Field-effect Transistor Applied to the Measurement of Water Percentage in Ethanol.

    Science.gov (United States)

    Shintani, Yukihiro; Kawarada, Hiroshi

    2017-01-01

    A polycrystalline diamond electrolyte-solution-gate field-effect transistor (BDD-SGFET) was successfully applied to the analysis of water content in ethanol. Due to the use of a no-gate-insulator FET, the developed sensor showed a four-times-faster response than the conventional Si-FET, and a ten-times-faster response than a glass electrode. The output voltage showed good linearity with respect to the water content. This result is of practical importance because the traditional water content measurement methods are impractical due to their slow response.

  1. A Pt/AlGaN/GaN heterostructure field-effect transistor (HFET) prepared by an electrophoretic deposition (EPD)-gate approach

    Science.gov (United States)

    Hung, Ching-Wen; Chang, Ching-Hong; Chen, Wei-Cheng; Chen, Chun-Chia; Chen, Huey-Ing; Tsai, Yu-Ting; Tsai, Jung-Hui; Liu, Wen-Chau

    2016-10-01

    Based on an electrophoretic deposition (EPD)-gate approach, a Pt/AlGaN/GaN heterostructure field-effect transistor (HFET) is fabricated and investigated at higher temperatures. The Pt/AlGaN interface with nearly oxide-free is verified by an Auger Electron Spectroscopy (AES) depth profile for the studied EPD-HFET. This result substantially enhances device performance at room temperature (300 K). Experimentally, the studied EPD-HFET exhibits a high turn-on voltage, a well suppression on gate leakage, a superior maximum drain saturation current, and an excellent extrinsic transconductance. Moreover, the microwave performance of an EPD-HFET is demonstrated at room temperature. Consequentially, this EPD-gate approach gives a promise for high-performance electronic applications.

  2. A Novel Sub-20 V Contact Gate Metal Oxide Semiconductor Field Effect Transistor with Fully Complementary Metal Oxide Semiconductor Compatible Process

    Science.gov (United States)

    Lee, Te Liang; Tsang Tsai, Ming; King, Ya Chin; Lin, Chrong Jung

    2013-04-01

    In this paper, a novel sub-20 V device which is called contact gate MOSFET (CGMOS) with fully CMOS logic compatible process is proposed and demonstrated. Comparing with lateral double diffusion MOSFET (LDMOS), CGMOS uses P substrate instead of N minus layer as drift region in logic process, and a contact on resistance protection oxide (RPO) layers to form an extra gate on the drain side of the channel region to provide a better gate control and reduce the surface field. This new device significantly rises up the breakdown voltage to 18 V with specific on-resistance 8.8 mΩ.mm2 in a small high voltage (HV) MOSFET area. Since there is no extra mask for creating the drift region or additional step for the wire bonding, CGMOS makes the integration of high voltage and logic circuits much simpler and area-saving.

  3. Human Aquaporin 4 Gating Dynamics under Perpendicularly-Oriented Electric-Field Impulses: A Molecular Dynamics Study

    Directory of Open Access Journals (Sweden)

    Paolo Marracino

    2016-07-01

    Full Text Available Human aquaporin 4 has been studied using molecular dynamics (MD simulations in the absence and presence of pulses of external static electric fields. The pulses were 10 ns in duration and 0.012–0.065 V/Å in intensity acting along both directions perpendicular to the pores. Water permeability and the dipolar response of all residues of interest (including the selectivity filter within the pores have been studied. Results showed decreased levels of water osmotic permeability within aquaporin channels during orthogonally-oriented field impulses, although care must be taken with regard to statistical certainty. This can be explained observing enhanced “dipolar flipping” of certain key residues, especially serine 211, histidine 201, arginine 216, histidine 95 and cysteine 178. These residues are placed at the extracellular end of the pore (serine 211, histidine 201, and arginine 216 and at the cytoplasm end (histidine 95 and cysteine 178, with the key role in gating mechanism, hence influencing water permeability.

  4. Development of a protection system for research reactor based in Field Programmable Gate Array - FPGA; Desenvolvimento de sistema de protecao para reator nuclear de pesquisa baseado em Field Programmable Gate Array - FPGA

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Roque Hudson da Silva

    2016-07-01

    This study presents a implementation purpose of a protection system for research nuclear reactors by using a programed device FPGA (Field Programmable Gate Array). As well as logic protection method involved on an automatic shutdown (TRIP) of a reactor, that ensure the security on such systems. These new control and operation mechanics are developed to guarantee that the security limits of a power plant are not exceeded, these mechanics can work isolated or in groups to safe guard the security levels. For this implementation to be completed, there will be presented the main aspects and concepts referred to protection systems, mostly about research nuclear reactors, with some applications terms exposed. The system proposed at this paper was developed following the VHDL (Very High Speed Integrated Circuits) hardware describing language, and the Modelsim software from Altera Software to program the automatic turning off routines, and hypothetical simulations for such. The results show that for every software application for supporting nuclear reactors, like security devices, they have to meet the IEC 60880 criteria. This paper have great importance, seeing that nuclear reactor security systems, are a basic element for ensure the reactor security. (author)

  5. Ferroelectric-gate field effect transistor memories device physics and applications

    CERN Document Server

    Ishiwara, Hiroshi; Okuyama, Masanori; Sakai, Shigeki; Yoon, Sung-Min

    2016-01-01

    This book provides comprehensive coverage of the materials characteristics, process technologies, and device operations for memory field-effect transistors employing inorganic or organic ferroelectric thin films. This transistor-type ferroelectric memory has interesting fundamental device physics and potentially large industrial impact. Among the various applications of ferroelectric thin films, the development of nonvolatile ferroelectric random access memory (FeRAM) has progressed most actively since the late 1980s and has achieved modest mass production levels for specific applications since 1995. There are two types of memory cells in ferroelectric nonvolatile memories. One is the capacitor-type FeRAM and the other is the field-effect transistor (FET)-type FeRAM. Although the FET-type FeRAM claims ultimate scalability and nondestructive readout characteristics, the capacitor-type FeRAMs have been the main interest for the major semiconductor memory companies, because the ferroelectric FET has fatal handic...

  6. Cardiac-respiratory self-gated cine ultra-short echo time (UTE) cardiovascular magnetic resonance for assessment of functional cardiac parameters at high magnetic fields.

    Science.gov (United States)

    Hoerr, Verena; Nagelmann, Nina; Nauerth, Arno; Kuhlmann, Michael T; Stypmann, Jörg; Faber, Cornelius

    2013-07-04

    To overcome flow and electrocardiogram-trigger artifacts in cardiovascular magnetic resonance (CMR), we have implemented a cardiac and respiratory self-gated cine ultra-short echo time (UTE) sequence. We have assessed its performance in healthy mice by comparing the results with those obtained with a self-gated cine fast low angle shot (FLASH) sequence and with echocardiography. 2D self-gated cine UTE (TE/TR = 314 μs/6.2 ms, resolution: 129 × 129 μm, scan time per slice: 5 min 5 sec) and self-gated cine FLASH (TE/TR = 3 ms/6.2 ms, resolution: 129 × 129 μm, scan time per slice: 4 min 49 sec) images were acquired at 9.4 T. Volume of the left and right ventricular (LV, RV) myocardium as well as the end-diastolic and -systolic volume was segmented manually in MR images and myocardial mass, stroke volume (SV), ejection fraction (EF) and cardiac output (CO) were determined. Statistical differences were analyzed by using Student t test and Bland-Altman analyses. Self-gated cine UTE provided high quality images with high contrast-to-noise ratio (CNR) also for the RV myocardium (CNRblood-myocardium = 25.5 ± 7.8). Compared to cine FLASH, susceptibility, motion, and flow artifacts were considerably reduced due to the short TE of 314 μs. The aortic valve was clearly discernible over the entire cardiac cycle. Myocardial mass, SV, EF and CO determined by self-gated UTE were identical to the values measured with self-gated FLASH and showed good agreement to the results obtained by echocardiography. Self-gated UTE allows for robust measurement of cardiac parameters of diagnostic interest. Image quality is superior to self-gated FLASH, rendering the method a powerful alternative for the assessment of cardiac function at high magnetic fields.

  7. Pulsed electromagnetic fields partially preserve bone mass, microarchitecture, and strength by promoting bone formation in hindlimb-suspended rats.

    Science.gov (United States)

    Jing, Da; Cai, Jing; Wu, Yan; Shen, Guanghao; Li, Feijiang; Xu, Qiaoling; Xie, Kangning; Tang, Chi; Liu, Juan; Guo, Wei; Wu, Xiaoming; Jiang, Maogang; Luo, Erping

    2014-10-01

    A large body of evidence indicates that pulsed electromagnetic fields (PEMF), as a safe and noninvasive method, could promote in vivo and in vitro osteogenesis. Thus far, the effects and underlying mechanisms of PEMF on disuse osteopenia and/or osteoporosis remain poorly understood. Herein, the efficiency of PEMF on osteoporotic bone microarchitecture, bone strength, and bone metabolism, together with its associated signaling pathway mechanism, was systematically investigated in hindlimb-unloaded (HU) rats. Thirty young mature (3-month-old), male Sprague-Dawley rats were equally assigned to control, HU, and HU + PEMF groups. The HU + PEMF group was subjected to daily 2-hour PEMF exposure at 15 Hz, 2.4 mT. After 4 weeks, micro-computed tomography (µCT) results showed that PEMF ameliorated the deterioration of trabecular and cortical bone microarchitecture. Three-point bending test showed that PEMF mitigated HU-induced reduction in femoral mechanical properties, including maximum load, stiffness, and elastic modulus. Moreover, PEMF increased serum bone formation markers, including osteocalcin (OC) and N-terminal propeptide of type 1 procollagen (P1NP); nevertheless, PEMF exerted minor inhibitory effects on bone resorption markers, including C-terminal crosslinked telopeptides of type I collagen (CTX-I) and tartrate-resistant acid phosphatase 5b (TRAcP5b). Bone histomorphometric analysis demonstrated that PEMF increased mineral apposition rate, bone formation rate, and osteoblast numbers in cancellous bone, but PEMF caused no obvious changes on osteoclast numbers. Real-time PCR showed that PEMF promoted tibial gene expressions of Wnt1, LRP5, β-catenin, OPG, and OC, but did not alter RANKL, RANK, or Sost mRNA levels. Moreover, the inhibitory effects of PEMF on disuse-induced osteopenia were further confirmed in 8-month-old mature adult HU rats. Together, these results demonstrate that PEMF alleviated disuse-induced bone loss by promoting skeletal anabolic activities

  8. Nanoscale Wet Etching of Physical-Vapor-Deposited Titanium Nitride and Its Application to Sub-30-nm-Gate-Length Fin-Type Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor Fabrication

    Science.gov (United States)

    Yongxun Liu,; Takahiro Kamei,; Kazuhiko Endo,; Shinichi O'uchi,; Junichi Tsukada,; Hiromi Yamauchi,; Tetsuro Hayashida,; Yuki Ishikawa,; Takashi Matsukawa,; Kunihiro Sakamoto,; Atsushi Ogura,; Meishoku Masahara,

    2010-06-01

    The nanoscale wet etching of physical-vapor-deposited (PVD) titanium nitride (TiN) and its application to sub-30-nm-gate-length fin-type double-gate metal-oxide-semiconductor field-effect transistor (FinFET) fabrication are systematically investigated. It is experimentally found that PVD-TiN side-etching depth can be controlled to be one-half of PVD-TiN thickness with precise time control using an ammonium hydroxide (NH4OH) : hydrogen peroxide (H2O2) : deionized water (H2O) = 1 : 2 : 5 solution at 60 °C. Using the developed nanoscale PVD-TiN wet etching technique, sub-30-nm-physical-gate-length FinFETs, 100-nm-tall fin-channel complementary MOS (CMOS) inverters and static random access memory (SRAM) half-cells have successfully been fabricated and demonstrated. These experimental results indicate that the developed nanoscale PVD-TiN wet etching technique is very useful for tall fin-channel CMOS fabrication.

  9. Feasibility Study of Extended-Gate-Type Silicon Nanowire Field-Effect Transistors for Neural Recording

    Science.gov (United States)

    Kang, Hongki; Kim, Jee-Yeon; Choi, Yang-Kyu; Nam, Yoonkey

    2017-01-01

    In this research, a high performance silicon nanowire field-effect transistor (transconductance as high as 34 µS and sensitivity as 84 nS/mV) is extensively studied and directly compared with planar passive microelectrode arrays for neural recording application. Electrical and electrochemical characteristics are carefully characterized in a very well-controlled manner. We especially focused on the signal amplification capability and intrinsic noise of the transistors. A neural recording system using both silicon nanowire field-effect transistor-based active-type microelectrode array and platinum black microelectrode-based passive-type microelectrode array are implemented and compared. An artificial neural spike signal is supplied as input to both arrays through a buffer solution and recorded simultaneously. Recorded signal intensity by the silicon nanowire transistor was precisely determined by an electrical characteristic of the transistor, transconductance. Signal-to-noise ratio was found to be strongly dependent upon the intrinsic 1/f noise of the silicon nanowire transistor. We found how signal strength is determined and how intrinsic noise of the transistor determines signal-to-noise ratio of the recorded neural signals. This study provides in-depth understanding of the overall neural recording mechanism using silicon nanowire transistors and solid design guideline for further improvement and development. PMID:28350370

  10. A digitizer based compact digital spectrometer for ion beam analysis using field programmable gate arrays and various energy algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Jäger, Markus [Faculty of Mathematics and Computer Science, University of Leipzig, PF 100920, 04009 Leipzig (Germany); Reinert, Tilo [Department of Physics, University of North Texas, 1155 Union Circle, Denton, Texas 76203 (United States)

    2013-08-15

    We report on the implementation of a compact multi-detector fully digital spectrometer and data acquisition system at a nuclear microprobe for ion beam analysis and imaging. The spectrometer design allows for system scalability with no restriction on the number of detectors. It consists of four-channel high-speed digitizer modules for detector signal acquisition and one low-speed digital-to-analog converter (DAC) module with two DAC channels and additional general purpose inputs/outputs to control ion beam scanning and data acquisition. Each digitizer module of the spectrometer provides its own Field Programmable Gate Array (FPGA) as digital signal processing unit to analyze detector signals as well as to synchronize the ion beam position in hard real-time. With the customized FPGA designs for all modules, all calculation intensive tasks are executed inside the modules, which reduces significantly the data stream to and CPU load on the control computer. To achieve an optimal energy resolution for all detector/preamplifier pulse shape characteristics, a user-definable infinite impulse response filter with high throughput for energy determination was implemented. The new spectrometer has an online data analysis feature, a compact size, and is able to process any type of detector signals such as particle induced x-ray emission, Rutherford backscattering spectrometry, or scanning transmission ion microscopy.

  11. A Soft Computing Approach to Crack Detection and Impact Source Identification with Field-Programmable Gate Array Implementation

    Directory of Open Access Journals (Sweden)

    Arati M. Dixit

    2013-01-01

    Full Text Available The real-time nondestructive testing (NDT for crack detection and impact source identification (CDISI has attracted the researchers from diverse areas. This is apparent from the current work in the literature. CDISI has usually been performed by visual assessment of waveforms generated by a standard data acquisition system. In this paper we suggest an automation of CDISI for metal armor plates using a soft computing approach by developing a fuzzy inference system to effectively deal with this problem. It is also advantageous to develop a chip that can contribute towards real time CDISI. The objective of this paper is to report on efforts to develop an automated CDISI procedure and to formulate a technique such that the proposed method can be easily implemented on a chip. The CDISI fuzzy inference system is developed using MATLAB’s fuzzy logic toolbox. A VLSI circuit for CDISI is developed on basis of fuzzy logic model using Verilog, a hardware description language (HDL. The Xilinx ISE WebPACK9.1i is used for design, synthesis, implementation, and verification. The CDISI field-programmable gate array (FPGA implementation is done using Xilinx’s Spartan 3 FPGA. SynaptiCAD’s Verilog Simulators—VeriLogger PRO and ModelSim—are used as the software simulation and debug environment.

  12. A counting-weighted calibration method for a field-programmable-gate-array-based time-to-digital converter

    Science.gov (United States)

    Chen, Yuan-Ho

    2017-05-01

    In this work, we propose a counting-weighted calibration method for field-programmable-gate-array (FPGA)-based time-to-digital converter (TDC) to provide non-linearity calibration for use in positron emission tomography (PET) scanners. To deal with the non-linearity in FPGA, we developed a counting-weighted delay line (CWD) to count the delay time of the delay cells in the TDC in order to reduce the differential non-linearity (DNL) values based on code density counts. The performance of the proposed CWD-TDC with regard to linearity far exceeds that of TDC with a traditional tapped delay line (TDL) architecture, without the need for nonlinearity calibration. When implemented in a Xilinx Vertix-5 FPGA device, the proposed CWD-TDC achieved time resolution of 60 ps with integral non-linearity (INL) and DNL of [-0.54, 0.24] and [-0.66, 0.65] least-significant-bit (LSB), respectively. This is a clear indication of the suitability of the proposed FPGA-based CWD-TDC for use in PET scanners.

  13. Zinc Oxide Nanorods Grown on Printed Circuit Board for Extended-Gate Field-Effect Transistor pH Sensor

    Science.gov (United States)

    Van Thanh, Pham; Nhu, Le Thi Quynh; Mai, Hong Hanh; Tuyen, Nguyen Viet; Doanh, Sai Cong; Viet, Nguyen Canh; Kien, Do Trung

    2017-06-01

    Zinc oxide (ZnO) nanorods (NRs) were grown directly on printed circuit boards with a 35- μm-thick copper layer using a seedless galvanic-cell hydrothermal process. The hexagonal structure of the synthesized ZnO NRs was observed by scanning electron microscopy. The microstructural characteristics of the as-grown ZnO NRs were investigated by x-ray diffraction analysis, revealing preferred (002) growth direction. Raman and photoluminescence spectra confirmed the high crystalline quality of the ZnO NRs. As-grown ZnO NRs were then grown for 7 h using the galvanic effect for use as the pH membrane of an extended-gate field-effect transistor pH sensor (pH-EGFET). The current-voltage characteristics showed sensitivity of 15.4 mV/pH and 0.26 ( μA)1/2/pH in the linear and saturated region, respectively. Due to their cost effectiveness, low-temperature processing, and ease of fabrication, such devices are potential candidates for use as flexible, low-cost, disposable biosensors.

  14. Piezoelectric potential gated field-effect transistor based on a free-standing ZnO wire.

    Science.gov (United States)

    Fei, Peng; Yeh, Ping-Hung; Zhou, Jun; Xu, Sheng; Gao, Yifan; Song, Jinhui; Gu, Yudong; Huang, Yanyi; Wang, Zhong Lin

    2009-10-01

    We report an external force triggered field-effect transistor based on a free-standing piezoelectric fine wire (PFW). The device consists of an Ag source electrode and an Au drain electrode at two ends of a ZnO PFW, which were separated by an insulating polydimethylsiloxane (PDMS) thin layer. The working principle of the sensor is proposed based on the piezoelectric potential gating effect. Once subjected to a mechanical impact, the bent ZnO PFW cantilever creates a piezoelectric potential distribution across it width at its root and simultaneously produces a local reverse depletion layer with much higher donor concentration than normal, which can dramatically change the current flowing from the source electrode to drain electrode when the device is under a fixed voltage bias. Due to the free-standing structure of the sensor device, it has a prompt response time less than 20 ms and quite high and stable sensitivity of 2%/microN. The effect from contact resistance has been ruled out.

  15. A counting-weighted calibration method for a field-programmable-gate-array-based time-to-digital converter

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yuan-Ho, E-mail: chenyh@mail.cgu.edu.tw [Department of Electronic Engineering, Chang Gung University, Tao-Yuan 333, Taiwan (China); Department of Radiation Oncology, Chang Gung Memorial Hospital, Tao-Yuan 333, Taiwan (China); Center for Reliability Sciences and Technologies, Chang Gung University, Tao-Yuan 333, Taiwan (China)

    2017-05-11

    In this work, we propose a counting-weighted calibration method for field-programmable-gate-array (FPGA)-based time-to-digital converter (TDC) to provide non-linearity calibration for use in positron emission tomography (PET) scanners. To deal with the non-linearity in FPGA, we developed a counting-weighted delay line (CWD) to count the delay time of the delay cells in the TDC in order to reduce the differential non-linearity (DNL) values based on code density counts. The performance of the proposed CWD-TDC with regard to linearity far exceeds that of TDC with a traditional tapped delay line (TDL) architecture, without the need for nonlinearity calibration. When implemented in a Xilinx Vertix-5 FPGA device, the proposed CWD-TDC achieved time resolution of 60 ps with integral non-linearity (INL) and DNL of [−0.54, 0.24] and [−0.66, 0.65] least-significant-bit (LSB), respectively. This is a clear indication of the suitability of the proposed FPGA-based CWD-TDC for use in PET scanners.

  16. Theory and implementation of a very high throughput true random number generator in field programmable gate array.

    Science.gov (United States)

    Wang, Yonggang; Hui, Cong; Liu, Chong; Xu, Chao

    2016-04-01

    The contribution of this paper is proposing a new entropy extraction mechanism based on sampling phase jitter in ring oscillators to make a high throughput true random number generator in a field programmable gate array (FPGA) practical. Starting from experimental observation and analysis of the entropy source in FPGA, a multi-phase sampling method is exploited to harvest the clock jitter with a maximum entropy and fast sampling speed. This parametrized design is implemented in a Xilinx Artix-7 FPGA, where the carry chains in the FPGA are explored to realize the precise phase shifting. The generator circuit is simple and resource-saving, so that multiple generation channels can run in parallel to scale the output throughput for specific applications. The prototype integrates 64 circuit units in the FPGA to provide a total output throughput of 7.68 Gbps, which meets the requirement of current high-speed quantum key distribution systems. The randomness evaluation, as well as its robustness to ambient temperature, confirms that the new method in a purely digital fashion can provide high-speed high-quality random bit sequences for a variety of embedded applications.

  17. A simple digital control system with field-programmable gate array for stabilization of CO2 laser output

    Science.gov (United States)

    Huang, Renshuai; Guo, Xiaoyang; Meng, Qinglong; Zhang, Bin

    2017-04-01

    A simple digital control system was designed to stabilize CO2 laser based on digital signal processing with the Field-Programmable Gate Array (FPGA) controlling chip and Very-High-Speed Integrated Circuit Hardware Description Language program. In this system, the control parameters were easily determined by software real-time control, and the control circuit was also designed compactly. In addition, the theoretical analysis on the stabilization of CO2 laser output characteristics was presented based on the photoacoustic effect, and the corresponding experiments on the stabilization of CO2 laser output characteristics were further performed. The results show that the output power of CO2 laser is stabilized at the peak with a relative power stability of 2.71%. Furthermore, the frequency of CO2 laser 9P(36) line is stabilized at the center of the laser gain curve with a relative stability of (1.57 ± 0.37)×10-8. This system has a potential of further improvements by optimizing the algorithm and choosing higher-speed signal processor.

  18. Plasma-deposited germanium nitride gate insulators for indium phosphide metal-insulator-semiconductor field-effect transistors

    Science.gov (United States)

    Johnson, Gregory A.; Kapoor, Vik J.

    1991-01-01

    Plasma-deposited germanium nitride was investigated for the first time as a possible gate insulator for InP compound semiconductor metal-insulator-semiconductor FET (MISFET) technology. The germanium nitride films were successfully deposited in a capacitively coupled parallel plate reactor at 13.56 MHz operation using GeH4/N2/NH3 and GeH4/N2 mixtures as reactant gases. The former process produced better quality films with enhanced uniformity, increased deposition rates, and increased resistivity. The breakdown field strength of the films was greater than 10 to the 6th V/cm. Auger electron spectroscopy did not indicate significant chemical composition differences between the two processes. For MISFETs with 2-micron channel lengths fabricated on InP, the device transconductance and threshold voltage for the GeH4/N2/NH3 process were 17 mS/mm and -3.6 V, respectively. The drain-source breakdown voltages were greater than 10 V.

  19. An Intelligent Architecture Based on Field Programmable Gate Arrays Designed to Detect Moving Objects by Using Principal Component Analysis

    Science.gov (United States)

    Bravo, Ignacio; Mazo, Manuel; Lázaro, José L.; Gardel, Alfredo; Jiménez, Pedro; Pizarro, Daniel

    2010-01-01

    This paper presents a complete implementation of the Principal Component Analysis (PCA) algorithm in Field Programmable Gate Array (FPGA) devices applied to high rate background segmentation of images. The classical sequential execution of different parts of the PCA algorithm has been parallelized. This parallelization has led to the specific development and implementation in hardware of the different stages of PCA, such as computation of the correlation matrix, matrix diagonalization using the Jacobi method and subspace projections of images. On the application side, the paper presents a motion detection algorithm, also entirely implemented on the FPGA, and based on the developed PCA core. This consists of dynamically thresholding the differences between the input image and the one obtained by expressing the input image using the PCA linear subspace previously obtained as a background model. The proposal achieves a high ratio of processed images (up to 120 frames per second) and high quality segmentation results, with a completely embedded and reliable hardware architecture based on commercial CMOS sensors and FPGA devices. PMID:22163406

  20. Theoretical Study of Triboelectric-Potential Gated/Driven Metal-Oxide-Semiconductor Field-Effect Transistor.

    Science.gov (United States)

    Peng, Wenbo; Yu, Ruomeng; He, Yongning; Wang, Zhong Lin

    2016-04-26

    Triboelectric nanogenerator has drawn considerable attentions as a potential candidate for harvesting mechanical energies in our daily life. By utilizing the triboelectric potential generated through the coupling of contact electrification and electrostatic induction, the "tribotronics" has been introduced to tune/control the charge carrier transport behavior of silicon-based metal-oxide-semiconductor field-effect transistor (MOSFET). Here, we perform a theoretical study of the performances of tribotronic MOSFET gated by triboelectric potential in two working modes through finite element analysis. The drain-source current dependence on contact-electrification generated triboelectric charges, gap separation distance, and externally applied bias are investigated. The in-depth physical mechanism of the tribotronic MOSFET operations is thoroughly illustrated by calculating and analyzing the charge transfer process, voltage relationship to gap separation distance, and electric potential distribution. Moreover, a tribotronic MOSFET working concept is proposed, simulated and studied for performing self-powered FET and logic operations. This work provides a deep understanding of working mechanisms and design guidance of tribotronic MOSFET for potential applications in micro/nanoelectromechanical systems (MEMS/NEMS), human-machine interface, flexible electronics, and self-powered active sensors.

  1. On the Use of Magnetic RAMs in Field-Programmable Gate Arrays

    Directory of Open Access Journals (Sweden)

    Y. Guillemenet

    2008-01-01

    Full Text Available This paper describes the integration of field-induced magnetic switching (FIMS and thermally assisted switching (TAS magnetic random access memories in FPGA design. The nonvolatility of the latter is achieved through the use of magnetic tunneling junctions (MTJs in the MRAM cell. A thermally assisted switching scheme helps to reduce power consumption during write operation in comparison to the writing scheme in the FIMS-MTJ device. Moreover, the nonvolatility of such a design based on either an FIMS or a TAS writing scheme should reduce both power consumption and configuration time required at each power up of the circuit in comparison to classical SRAM-based FPGAs. A real-time reconfigurable (RTR micro-FPGA using FIMS-MRAM or TAS-MRAM allows dynamic reconfiguration mechanisms, while featuring simple design architecture.

  2. A comparative design view for accurate control of servos using a field programmable gate array

    Science.gov (United States)

    Tickle, A. J.; Harvey, P. K.; Wu, F.; Buckle, J. R.; Smith, J. S.

    2009-07-01

    An embedded system is a special-purpose computer system designed to perform one or a few dedicated functions. Altera DSP Builder presents designers and users with an alternate approach when creating their systems by employing a blockset similar to that already used in Simulink. The application considered in this paper is the design of a Pulse Width Modulation (PWM) system for use in stereo vision. PWM can replace a digital-to-analogue converter to control audio speakers, LED intensity, motor speed, and servo position. Rather than the conventional HDL coding approach this Simulink approach provides an easy understanding platform to the PWM design. This paper includes a comparison between two approaches regarding resource usage and flexibility etc. Included is how DSP Builder manipulates an onboard clock signal, in order to create the control pulses to the "raw" coding of a PWM generator in VHDL. Both methods were shown to a selection of people and their views on which version they would subsequently use in their relative fields is discussed.

  3. A comparative design view for accurate control of servos using a field programmable gate array

    Energy Technology Data Exchange (ETDEWEB)

    Tickle, A J; Harvey, P K; Smith, J S [Intelligence Engineering and Industrial Automation Research Group, Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3GJ (United Kingdom); Wu, F [RF Engines Ltd, Innovation Centre, St. Cross Business Park, Newport, Isle of Wight, PO30 5WB (United Kingdom); Buckle, J R, E-mail: a.j.tickle@liverpool.ac.u [Power Systems and Power Engineering Research Division, Department of Electronics and Electrical Engineering, University of Glasgow, Glasgow G12 8LT (United Kingdom)

    2009-07-01

    An embedded system is a special-purpose computer system designed to perform one or a few dedicated functions. Altera DSP Builder presents designers and users with an alternate approach when creating their systems by employing a blockset similar to that already used in Simulink. The application considered in this paper is the design of a Pulse Width Modulation (PWM) system for use in stereo vision. PWM can replace a digital-to-analogue converter to control audio speakers, LED intensity, motor speed, and servo position. Rather than the conventional HDL coding approach this Simulink approach provides an easy understanding platform to the PWM design. This paper includes a comparison between two approaches regarding resource usage and flexibility etc. Included is how DSP Builder manipulates an onboard clock signal, in order to create the control pulses to the 'raw' coding of a PWM generator in VHDL. Both methods were shown to a selection of people and their views on which version they would subsequently use in their relative fields is discussed.

  4. HARDWARE REALIZATION OF CANNY EDGE DETECTION ALGORITHM FOR UNDERWATER IMAGE SEGMENTATION USING FIELD PROGRAMMABLE GATE ARRAYS

    Directory of Open Access Journals (Sweden)

    ALEX RAJ S. M.

    2017-09-01

    Full Text Available Underwater images raise new challenges in the field of digital image processing technology in recent years because of its widespread applications. There are many tangled matters to be considered in processing of images collected from water medium due to the adverse effects imposed by the environment itself. Image segmentation is preferred as basal stage of many digital image processing techniques which distinguish multiple segments in an image and reveal the hidden crucial information required for a peculiar application. There are so many general purpose algorithms and techniques that have been developed for image segmentation. Discontinuity based segmentation are most promising approach for image segmentation, in which Canny Edge detection based segmentation is more preferred for its high level of noise immunity and ability to tackle underwater environment. Since dealing with real time underwater image segmentation algorithm, which is computationally complex enough, an efficient hardware implementation is to be considered. The FPGA based realization of the referred segmentation algorithm is presented in this paper.

  5. Ge/IIIV fin field-effect transistor common gate process and numerical simulations

    Science.gov (United States)

    Chen, Bo-Yuan; Chen, Jiann-Lin; Chu, Chun-Lin; Luo, Guang-Li; Lee, Shyong; Chang, Edward Yi

    2017-04-01

    This study investigates the manufacturing process of thermal atomic layer deposition (ALD) and analyzes its thermal and physical mechanisms. Moreover, experimental observations and computational fluid dynamics (CFD) are both used to investigate the formation and deposition rate of a film for precisely controlling the thickness and structure of the deposited material. First, the design of the TALD system model is analyzed, and then CFD is used to simulate the optimal parameters, such as gas flow and the thermal, pressure, and concentration fields, in the manufacturing process to assist the fabrication of oxide-semiconductors and devices based on them, and to improve their characteristics. In addition, the experiment applies ALD to grow films on Ge and GaAs substrates with three-dimensional (3-D) transistors having high electric performance. The electrical analysis of dielectric properties, leakage current density, and trapped charges for the transistors is conducted by high- and low-frequency measurement instruments to determine the optimal conditions for 3-D device fabrication. It is anticipated that the competitive strength of such devices in the semiconductor industry will be enhanced by the reduction of cost and improvement of device performance through these optimizations.

  6. Ultra-thin films of polysilsesquioxanes possessing 3-methacryloxypropyl groups as gate insulator for organic field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Nakahara, Yoshio; Kawa, Haruna [Department of Applied Chemistry, Faculty of Systems Engineering, Wakayama University, 930 Sakae-dani, Wakayama 640-8510 (Japan); Yoshiki, Jun [Division of Information and Electronic Engineering, Faculty of Engineering, Muroran Institute of Technology, 27-1 Mizumoto-cho, Muroran 050-8585 (Japan); Kumei, Maki; Yamamoto, Hiroyuki; Oi, Fumio [Konishi Chemical IND. Co., LTD., 3-4-77 Kozaika, Wakayama 641-0007 (Japan); Yamakado, Hideo [Department of Applied Chemistry, Faculty of Systems Engineering, Wakayama University, 930 Sakae-dani, Wakayama 640-8510 (Japan); Fukuda, Hisashi [Division of Engineering for Composite Functions, Faculty of Engineering, Muroran Institute of Technology, 27-1 Mizumoto-cho, Muroran 050-8585 (Japan); Kimura, Keiichi, E-mail: kkimura@center.wakayama-u.ac.jp [Department of Applied Chemistry, Faculty of Systems Engineering, Wakayama University, 930 Sakae-dani, Wakayama 640-8510 (Japan)

    2012-10-01

    Polysilsesquioxanes (PSQs) possessing 3-methacryloxypropyl groups as an organic moiety of the side chain were synthesized by sol-gel condensation copolymerization of the corresponding trialkoxysilanes. The ultra-thin PSQ film with a radical initiator and a cross-linking agent was prepared by a spin-coating method, and the film was cured integrally at low temperatures of less than 120 Degree-Sign C through two different kinds of polymeric reactions, which were radical polymerization of vinyl groups and sol-gel condensation polymerization of terminated silanol and alkoxy groups. The obtained PSQ film showed the almost perfect solubilization resistance to acetone, which is a good solvent of PSQ before polymerization. It became clear by atomic force microscopy observation that the surface of the PSQ film was very smooth at a nano-meter level. Furthermore, pentacene-based organic field-effect transistor (OFET) with the PSQ film as a gate insulator showed typical p-channel enhancement mode operation characteristics and therefore the ultra-thin PSQ film has the potential to be applicable for solution-processed OFET systems. - Highlights: Black-Right-Pointing-Pointer Polysilsesquioxanes (PSQs) possessing 3-methacryloxypropyl groups were synthesized. Black-Right-Pointing-Pointer The ultra-thin PSQ film could be cured at low temperatures of less than 120 Degree-Sign C. Black-Right-Pointing-Pointer The PSQ film showed the almost perfect solubilization resistance to organic solvent. Black-Right-Pointing-Pointer The surface of the PSQ film was very smooth at a nano-meter level. Black-Right-Pointing-Pointer Pentacene-based organic field-effect transistor with the PSQ film was fabricated.

  7. Highly specific and sensitive non-enzymatic determination of uric acid in serum and urine by extended gate field effect transistor sensors.

    Science.gov (United States)

    Guan, Weihua; Duan, Xuexin; Reed, Mark A

    2014-01-15

    A potentiometric non-enzymatic sensor using off-chip extended-gate field effect transistor (EGFET) with a ferrocenyl-alkanethiol modified gold electrode is demonstrated for determining the uric acid concentration in human serum and urine. Hexacyanoferrate (II) and (III) ions are used as redox reagent. This potentiometric sensor measures the interface potential on the ferrocene immobilized gold electrode, which is modulated by the redox reaction between uric acid and hexacyanoferrate ions. The device shows a near Nernstian response to uric acid and is highly specific. The interference that comes from glucose, bilirubin, ascorbic acid and hemoglobin is negligible in normal concentration range of these interferents. The sensor also exhibits excellent long term reliability. This extended gate field effect transistor based sensors can be used as a point of care UA testing tool, due to the small size, low cost, and low sample volume consumption. © 2013 Elsevier B.V. All rights reserved.

  8. Normally-off AlGaN/GaN-on-Si metal-insulator-semiconductor heterojunction field-effect transistor with nitrogen-incorporated silicon oxide gate insulator

    Science.gov (United States)

    Roh, Seung-Hyun; Eom, Su-Keun; Choi, Gwang-Ho; Kang, Myoung-Jin; Kim, Dong-Hwan; Hwang, Il-Hwan; Seo, Kwang-Seok; Lee, Jae-Gil; Byun, Young-Chul; Cha, Ho-Young

    2017-08-01

    We have developed a nitrogen-incorporated silicon oxide (SiOxNy) deposition process using plasma enhanced atomic layer deposition (PEALD) for the gate insulator of recessed-gate Al-GaN/GaN metal-insulator-semiconductor heterojunction field-effect transistors. The SiOxNy film deposited on a recessed GaN surface exhibited a breakdown field of 13.2 MV/cm and a conduction band offset of 3.37 eV, which are the highest values reported for GaN MIS structures to the best of our knowledge. The fabricated normally-off transistor exhibited very promising characteristics such as a threshold voltage of 2.2 V, a maximum drain current density of 428 mA/mm, and a breakdown voltage of 928 V.

  9. Sub-0.5-µm gate doped-channel field-effect transistors with HEMT-like channel using thermally reflowed photoresist and spin-on glass

    Science.gov (United States)

    Tan, S. W.; Chen, W. T.; Chu, M. Y.; Lour, W. S.

    2004-02-01

    In this paper we report on a new sub-0.5-µm gate-length field-effect transistor (FET) processing technique by using conventional i-line optical lithography. The key methodology is to thermally reflow the patterned photoresist upon two-step spin-coated spin-on glass (SOG). According to this new process, the deposited gate metal has its final length and thickness separately determined by taped resist profile and SOG thickness. Furthermore, undercutting formed during isotropic etch SOG film is beneficial to the subsequent lift-off process, achieving high fabrication yield. The implemented gate length is as short as 0.41 µm. Then it was successfully applied to fabrication of a newly designed hetero-doped-channel FET (HDCFET) with digital-graded InxGa1-xAs multilayer forming a HEMT-like channel. This digital-graded InxGa1-xAs channel by changing x values from 0.1 to 0.2 has most electrons closer to the gate metal. The measured sheet carrier density and mobility are 4.3 × 1012 cm-2 and 3560 cm2 V-1 s-1, respectively, while the peak carrier concentration is larger than 1 × 1019 cm-3. A fabricated 0.41 × 100 µm2 HDCFET exhibits the maximum transconductance of 370 mS mm-1 with an output current larger than 535 mA mm-1 and ft(fmax) of 26 (32) GHz.

  10. Capacitive effective thickness of a few nanometers by atomic layer deposition and device performance in Ge gate-all-around fin field effect transistors

    Science.gov (United States)

    Chu, Chu-Lin; Chen, Bo-Yuan; Fuh, Yiin-Kuen

    2015-10-01

    Ge gate-all-around fin field-effect transistors (Ge FinFETs) with a capacitive effective thickness of a few nanometers have been successfully achieved via atomic-layer-deposited (ALD) high-dielectric Al2O3 on GeO2/Ge and by adopting low-cost thermo ALD equipment. The MOS interface properties of the ZrO2 or Al2O3/GeO2/Ge structures have been studied systematically. It has been found that a GeO2 interfacial layer that is greater than approximately 2.5 nm results in a significant degradation of the MOS interfaces, while an equivalent oxide thickness of FinFET's value has been demonstrated with the Al2O3/GeO2/Ge gate stack prepared using a thermal ALD layer of Al2O3. The experimental results indicate that the MOS interface quality obtained with the technique developed for high-permittivity/Ge gate stacks is also extremely useful for the fabrication of triangle-fin complementary metal oxide semiconductor devices. An I/I ratio of 3.2×104 and a subthreshold swing of 103 mV/dec were obtained for the triangular n-type Ge gate-all-around FET with (111) sidewalls. The drain current at VGS-VT=VDS=-1.5 V is 88 mA/mm.

  11. Far-field and near-field monitoring of hybridized optical modes from Au nanoprisms suspended on a graphene/Si nanopillar array.

    Science.gov (United States)

    Nien, Li-Wei; Chen, Kai; Dao, Thang Duy; Ishii, Satoshi; Hsueh, Chun-Hway; Nagao, Tadaaki

    2017-11-09

    The optical hybridization of localized surface plasmons and photonic modes of dielectric nanostructures provides us wide arenas of opportunities for designing tunable nanophotonics with excellent spectral selectivity, signal enhancement, and light harvesting for many optical applications. Graphene-supported Au nanoprisms on a periodic Si nanopillar array will be an ideal model system for examining such an optical hybridization effect between plasmonic modes and photonic modes. Here, through the measurement of the reflectance spectra as well as graphene phonons by surface-enhanced Raman scattering (SERS), we investigated both the far-field and near-field properties of these optically hybridized modes. The effects of photonic modes and Mie resonances of the Si nanopillars on the localized surface plasmons of the Au nanoprisms and on their near-field enhancement were experimentally elucidated through the measurements of graphene phonons using two excitation lasers with wavelengths of 532 and 785 nm. The wavelength-dependent SERS intensities of monolayer graphene are clearly understood in terms of the optical hybridization, and the SERS enhancement factor estimated from finite-difference time-domain simulations exhibited good agreement with the measurements. The elucidated spectral tunability in the near-field light-matter interaction would be useful for potential applications in various types of graphene-based photonics.

  12. Single-Event Effect (SEE) Survey of Advanced Reconfigurable Field Programmable Gate Arrays: NASA Electronic Parts and Packaging (NEPP) Program Office of Safety and Mission Assurance

    Science.gov (United States)

    Allen, Gregory

    2011-01-01

    The NEPP Reconfigurable Field-Programmable Gate Array (FPGA) task has been charged to evaluate reconfigurable FPGA technologies for use in space. Under this task, the Xilinx single-event-immune, reconfigurable FPGA (SIRF) XQR5VFX130 device was evaluated for SEE. Additionally, the Altera Stratix-IV and SiliconBlue iCE65 were screened for single-event latchup (SEL).

  13. COMPARATIVE STUDY OF MAXIMUM POWER POINT TRACKING USING LINEAR KALMAN FILTER & UNSCENTED KALMAN FILTER FOR SOLAR PHOTOVOLTAIC ARRAY ON FIELD PROGRAMMABLE GATE ARRAY

    OpenAIRE

    Ramchandani, Varun; Pamarthi, Kranthi; Chowdhury, Shubhajit Roy

    2012-01-01

    The paper proposes comparative study of Field Programmable Gate Array implementation of 2 closely related approaches to track maximum power point of a solar photovoltaic array. The current work uses 2 versions of kalman filter viz. linear kalman filter and unscented kalman filter to track maximum power point. Using either of these approach the maximum power point tracking (MPPT) becomes much faster than using the conventional Perturb & Observe approach specifically in case of sudden weather c...

  14. Low-Programmable-Voltage Nonvolatile Memory Devices Based on Omega-shaped Gate Organic Ferroelectric P(VDF-TrFE) Field Effect Transistors Using p-type Silicon Nanowire Channels

    National Research Council Canada - National Science Library

    Ngoc Huynh Van Jae-Hyun Lee Dongmok Whang Dae Joon Kang

    2015-01-01

    A facile approach was demonstrated for fabricating high-performance nonvolatile memory devices based on ferroelectric-gate field effect transistors using a p-type Si nanowire coated with omega-shaped...

  15. Thermally oxidized 2D TaS2 as a high-κ gate dielectric for MoS2 field-effect transistors

    Science.gov (United States)

    Chamlagain, Bhim; Cui, Qingsong; Paudel, Sagar; Ming-Cheng Cheng, Mark; Chen, Pai-Yen; Zhou, Zhixian

    2017-09-01

    We report a new approach to integrating high-κ dielectrics in both bottom- and top-gated MoS2 field-effect transistors (FETs) through thermal oxidation and mechanical assembly of layered two-dimensional (2D) TaS2. Combined x-ray photoelectron spectroscopy (XPS), optical microscopy, atomic force microscopy (AFM), and capacitance-voltage (C-V) measurements confirm that multilayer TaS2 flakes can be uniformly transformed to Ta2O5 with a high dielectric constant of ~15.5 via thermal oxidation, while preserving the geometry and ultra-smooth surfaces of 2D TMDs. Top-gated MoS2 FETs fabricated using the thermally oxidized Ta2O5 as gate dielectric demonstrate a high current on/off ratio approaching 106, a subthreshold swing (SS) down to 61 mV/dec, and a field-effect mobility exceeding 60 cm2 V-1 s-1 at room temperature, indicating high dielectric quality and low interface trap density.

  16. Nanosecond pulsed electric fields depolarize transmembrane potential via voltage-gated K+, Ca2+and TRPM8 channels in U87 glioblastoma cells.

    Science.gov (United States)

    Burke, Ryan C; Bardet, Sylvia M; Carr, Lynn; Romanenko, Sergii; Arnaud-Cormos, Delia; Leveque, Philippe; O'Connor, Rodney P

    2017-10-01

    Nanosecond pulsed electric fields (nsPEFs) have a variety of applications in the biomedical and biotechnology industries. Cancer treatment has been at the forefront of investigations thus far as nsPEFs permeabilize cellular and intracellular membranes leading to apoptosis and necrosis. nsPEFs may also influence ion channel gating and have the potential to modulate cell physiology without poration of the membrane. This phenomenon was explored using live cell imaging and a sensitive fluorescent probe of transmembrane voltage in the human glioblastoma cell line, U87 MG, known to express a number of voltage-gated ion channels. The specific ion channels involved in the nsPEF response were screened using a membrane potential imaging approach and a combination of pharmacological antagonists and ion substitutions. It was found that a single 10ns pulsed electric field of 34kV/cm depolarizes the transmembrane potential of cells by acting on specific voltage-sensitive ion channels; namely the voltage and Ca2 + gated BK potassium channel, L- and T-type calcium channels, and the TRPM8 transient receptor potential channel. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Impact of boron diffusion on oxynitrided gate oxides in 4H-SiC metal-oxide-semiconductor field-effect transistors

    Science.gov (United States)

    Cabello, M.; Soler, V.; Montserrat, J.; Rebollo, J.; Rafí, J. M.; Godignon, P.

    2017-07-01

    An alternative gate oxide configuration is proposed to enhance the SiO2/SiC interface quality, enabling high mobility 4H-SiC lateral metal-oxide-semiconductor field-effect transistors (MOSFETs). The gate oxide is prepared by the combination of rapid thermal oxidation in N2O ambient, boron diffusion into SiO2, and plasma enhanced chemical vapor deposition of tetraethyl orthosilicate oxide. Capacitance-voltage (C-V) and conductance-voltage (G-V) measurements on fabricated capacitors reveal a reduction of both interface trap and near interface oxide trap densities. The fabrication of MOSFETs with very high field-effect mobility (μfe) values, up to 160 cm2/V s, is enabled. Several channel orientations, with respect to the wafer flat {11 2 ¯ 0}, have been studied to check μfe values and isotropy. Higher μfe values are obtained for a channel orientation of 90°. Boron distribution is studied by secondary ion mass spectrometry (SIMS) and time of flight SIMS. We propose that the combination of boron and nitrogen induces changes in the structure of the gate oxide which are positive in terms of the SiO2/SiC interface quality.

  18. Chemical Gated Field Effect Transistor by Hybrid Integration of One-Dimensional Silicon Nanowire and Two-Dimensional Tin Oxide Thin Film for Low Power Gas Sensor.

    Science.gov (United States)

    Han, Jin-Woo; Rim, Taiuk; Baek, Chang-Ki; Meyyappan, M

    2015-09-30

    Gas sensors based on metal-oxide-semiconductor transistor with the polysilicon gate replaced by a gas sensitive thin film have been around for over 50 years. These are not suitable for the emerging mobile and wearable sensor platforms due to operating voltages and powers far exceeding the supply capability of batteries. Here we present a novel approach to decouple the chemically sensitive region from the conducting channel for reducing the drive voltage and increasing reliability. This chemically gated field effect transistor uses silicon nanowire for the current conduction channel with a tin oxide film on top of the nanowire serving as the gas sensitive medium. The potential change induced by the molecular adsorption and desorption allows the electrically floating tin oxide film to gate the silicon channel. As the device is designed to be normally off, the power is consumed only during the gas sensing event. This feature is attractive for the battery operated sensor and wearable electronics. In addition, the decoupling of the chemical reaction and the current conduction regions allows the gas sensitive material to be free from electrical stress, thus increasing reliability. The device shows excellent gas sensitivity to the tested analytes relative to conventional metal oxide transistors and resistive sensors.

  19. Recent Progress of Ferroelectric-Gate Field-Effect Transistors and Applications to Nonvolatile Logic and FeNAND Flash Memory

    Science.gov (United States)

    Sakai, Shigeki; Takahashi, Mitsue

    2010-01-01

    We have investigated ferroelectric-gate field-effect transistors (FeFETs) with Pt/SrBi2Ta2O9/(HfO2)x(Al2O3)1−x (Hf-Al-O) and Pt/SrBi2Ta2O9/HfO2 gate stacks. The fabricated FeFETs have excellent data retention characteristics: The drain current ratio between the on- and off-states of a FeFET was more than 2 × 106 after 12 days, and the decreasing rate of this ratio was so small that the extrapolated drain current ratio after 10 years is larger than 1 × 105. A fabricated self-aligned gate Pt/SrBi2Ta2O9/Hf-Al-O/Si FET revealed a sufficiently large drain current ratio of 2.4 × 105 after 33.5 day, which is 6.5 × 104 after 10 years by extrapolation. The developed FeFETs also revealed stable retention characteristics at an elevated temperature up to 120 °C and had small transistor threshold voltage (Vth) distribution. The Vth can be adjusted by controlling channel impurity densities for both n-channel and p-channel FeFETs. These performances are now suitable to integrated circuit application with nonvolatile functions. Fundamental properties for the applications to ferroelectric-CMOS nonvolatile logic-circuits and to ferroelectric-NAND flash memories are demonstrated. PMID:28883363

  20. Cross-Sectional Channel Shape Dependence of Short-Channel Effects in Fin-Type Double-Gate Metal Oxide Semiconductor Field-Effect Transistors

    Science.gov (United States)

    Liu, Yongxun; Ishii, Kenichi; Masahara, Meishoku; Tsutsumi, Toshiyuki; Takashima, Hidenori; Yamauchi, Hiromi; Suzuki, Eiichi

    2004-04-01

    The dependence of short-channel effects (SCEs) on the cross-sectional channel shape of the fin-type double-gate metal oxide semiconductor field-effect transistors (MOSFETs) has been experimentally investigated from the viewpoint of fin fabrication. The three types of fin-type double-gate MOSFETs (FinFETs) with a rectangular-cross-section channel on a (110)-oriented silicon-on-insulator (SOI) wafer, and a triangular and trapezoidal channels on a (100)-oriented SOI wafer were fabricated using the same orientation-dependent wet etching process. The experimental results show that the SCEs in rectangular-cross-section silicon (Si)-fin channel devices are well suppressed compared with those in a triangular or a trapezoidal Si-fin channel device fabricated using a similar mask pattern, in the regimes of the gate length of less than 85 nm and Si fin height of larger than 65 nm. The presented experimental results are valuable for FinFET design and fabrication.

  1. Recent Progress of Ferroelectric-Gate Field-Effect Transistors and Applications to Nonvolatile Logic and FeNAND Flash Memory

    Directory of Open Access Journals (Sweden)

    Mitsue Takahashi

    2010-11-01

    Full Text Available We have investigated ferroelectric-gate field-effect transistors (FeFETs with Pt/SrBi2Ta2O9/(HfO2x(Al2O31−x (Hf-Al-O and Pt/SrBi2Ta2O9/HfO2 gate stacks. The fabricated FeFETs have excellent data retention characteristics: The drain current ratio between the on- and off-states of a FeFET was more than 2 × 106 after 12 days, and the decreasing rate of this ratio was so small that the extrapolated drain current ratio after 10 years is larger than 1 × 105. A fabricated self-aligned gate Pt/SrBi2Ta2O9/Hf-Al-O/Si FET revealed a sufficiently large drain current ratio of 2.4 × 105 after 33.5 day, which is 6.5 × 104 after 10 years by extrapolation. The developed FeFETs also revealed stable retention characteristics at an elevated temperature up to 120 °C and had small transistor threshold voltage (Vth distribution. The Vth can be adjusted by controlling channel impurity densities for both n-channel and p-channel FeFETs. These performances are now suitable to integrated circuit application with nonvolatile functions. Fundamental properties for the applications to ferroelectric-CMOS nonvolatile logic-circuits and to ferroelectric-NAND flash memories are demonstrated.

  2. Modelling flow-induced vibrations of gates in hydraulic structures

    NARCIS (Netherlands)

    Erdbrink, C.D.

    2014-01-01

    The dynamic behaviour of gates in hydraulic structures caused by passing flow poses a potential threat to flood protection. Complex interactions between the turbulent flow and the suspended gate body may induce undesired vibrations. This thesis contributes to a better understanding and prevention of

  3. Quantum ballistic analysis of transition metal dichalcogenides based double gate junctionless field effect transistor and its application in nano-biosensor

    Science.gov (United States)

    Shadman, Abir; Rahman, Ehsanur; Khosru, Quazi D. M.

    2017-11-01

    To reduce the thermal budget and the short channel effects in state of the art CMOS technology, Junctionless field effect transistor (JLFET) has been proposed in the literature. Numerous experimental, modeling, and simulation based works have been done on this new FET with bulk materials for various geometries until now. On the other hand, the two-dimensional layered material is considered as an alternative to current Si technology because of its ultra-thin body and high mobility. Very recently few simulation based works have been done on monolayer molybdenum disulfide based JLFET mainly to show the advantage of JLFET over conventional FET. However, no comprehensive simulation-based work has been done for double gate JLFET keeping in mind the prominent transition metal dichalcogenides (TMDC) to the authors' best knowledge. In this work, we have studied quantum ballistic drain current-gate voltage characteristics of such FETs within non-equilibrium Green's function (NEGF) framework. Our simulation results reveal that all these TMDC materials are viable options for implementing state of the art Junctionless MOSFET with emphasis on their performance at short gate lengths. Besides evaluating the prospect of TMDC materials in the digital logic application, the performance of Junctionless Double Gate trilayer TMDC heterostructure FET for the label-free electrical detection of biomolecules in dry environment has been investigated for the first time to the authors' best knowledge. The impact of charge neutral biomolecules on the electrical characteristics of the biosensor has been analyzed under dry environment situation. Our study shows that these materials could provide high sensitivity in the sub-threshold region as a channel material in nano-biosensor, a trend demonstrated by silicon on insulator FET sensor in the literature. Thus, going by the trend of replacing silicon with these novel materials in device level, TMDC heterostructure could be a viable alternative to

  4. Broken Symmetry Quantum Hall states in Dual Gated ABA Trilayer Graphene

    Science.gov (United States)

    Lee, Yongjin; Velasco, Jairo, Jr.; Tran, David; Zhang, Fan; Bao, Wenzhong; Jing, Lei; Myhro, Kevin; Smirnov, Dmitry; Lau, Jeanie

    2013-03-01

    We perform low temperature transport measurements on dual-gated suspended trilayer graphene in the quantum Hall (QH) regime. We observe QH plateaus at filling factors ν = -8, -2, 2, 6, and 10, in agreement with the full-parameter tight binding calculations. In high magnetic fields, oddinteger plateaus are also resolved, indicating almost complete lifting of the 12-fold degeneracy of the lowest Landau levels (LL). Under an out-of-plane electric field E ⊥. We observe degeneracy breaking and transitions between QH plateaus. Interestingly, depending on its direction, E ⊥selectively breaks the LL degeneracies in the electron-doped or hole-doped regimes.

  5. Nanofabrication of Arrays of Silicon Field Emitters with Vertical Silicon Nanowire Current Limiters and Self-Aligned Gates

    Science.gov (United States)

    2016-08-19

    surrounds the nanowires . After the deposition of the dielectric stack, a self-aligned polysilicon gate is defined. A timed etch of the nitride is performed... tunneling through the sur- face barrier . Small deviations from a linear relationship could be due to quantum effects in the emitter tip [33], a non...triangular tunneling barrier due to emitter geometry, or space charge limitation following Child’s law [34]. The saturation of the anode current observed in

  6. Extended Characterization of the Common-Source and Common-Gate Amplifiers using a Metal-Ferroelectric-Semiconductor Field Effect Transistor

    Science.gov (United States)

    Hunt, Mitchell; Sayyah, Rana; Mitchell, Cody; Laws, Crystal; MacLeod, Todd C.; Ho, Fat D.

    2013-01-01

    Collected data for both common-source and common-gate amplifiers is presented in this paper. Characterizations of the two amplifier circuits using metal-ferroelectric-semiconductor field effect transistors (MFSFETs) are developed with wider input frequency ranges and varying device sizes compared to earlier characterizations. The effects of the ferroelectric layer's capacitance and variation load, quiescent point, or input signal on each circuit are discussed. Comparisons between the MFSFET and MOSFET circuit operation and performance are discussed at length as well as applications and advantages for the MFSFETs.

  7. A New Analytical Subthreshold Behavior Model for Single-Halo, Dual-Material Gate Silicon-on-Insulator Metal Oxide Semiconductor Field Effect Transistor

    Science.gov (United States)

    Chiang, Te-Kuang

    2008-11-01

    On the basis of the exact solution of the two-dimensional Poisson equation, a new analytical subthreshold behavior model consisting of the two-dimensional potential, threshold voltage, and subthreshold current for the single-halo, dual-material gate (SHDMG) silicon-on-insulator (SOI) metal oxide semiconductor field effect transistor (MOSFET) is developed. The model is verified by the good agreement with a numerical simulation using the device simulator MEDICI. The model not only offers a physical insight into device physics but is also an efficient device model for the circuit simulation.

  8. A field programmable gate array-based reconfigurable smart-sensor network for wireless monitoring of new generation computer numerically controlled machines.

    Science.gov (United States)

    Moreno-Tapia, Sandra Veronica; Vera-Salas, Luis Alberto; Osornio-Rios, Roque Alfredo; Dominguez-Gonzalez, Aurelio; Stiharu, Ion; Romero-Troncoso, Rene de Jesus

    2010-01-01

    Computer numerically controlled (CNC) machines have evolved to adapt to increasing technological and industrial requirements. To cover these needs, new generation machines have to perform monitoring strategies by incorporating multiple sensors. Since in most of applications the online Processing of the variables is essential, the use of smart sensors is necessary. The contribution of this work is the development of a wireless network platform of reconfigurable smart sensors for CNC machine applications complying with the measurement requirements of new generation CNC machines. Four different smart sensors are put under test in the network and their corresponding signal processing techniques are implemented in a Field Programmable Gate Array (FPGA)-based sensor node.

  9. An automated wide-field time-gated optically sectioning fluorescence lifetime imaging multiwell plate reader for high-content analysis of protein-protein interactions

    Science.gov (United States)

    Alibhai, Dominic; Kumar, Sunil; Kelly, Douglas; Warren, Sean; Alexandrov, Yuriy; Munro, Ian; McGinty, James; Talbot, Clifford; Murray, Edward J.; Stuhmeier, Frank; Neil, Mark A. A.; Dunsby, Chris; French, Paul M. W.

    2011-03-01

    We describe an optically-sectioned FLIM multiwell plate reader that combines Nipkow microscopy with wide-field time-gated FLIM, and its application to high content analysis of FRET. The system acquires sectioned FLIM images in protein. It has been applied to study the formation of immature HIV virus like particles (VLPs) in live cells by monitoring Gag-Gag protein interactions using FLIM FRET of HIV-1 Gag transfected with CFP or YFP. VLP formation results in FRET between closely packed Gag proteins, as confirmed by our FLIM analysis that includes automatic image segmentation.

  10. Optical devices having flakes suspended in a host fluid to provide a flake/fluid system providing flakes with angularly dependent optical properties in response to an alternating current electric field due to the dielectric properties of the system

    Science.gov (United States)

    Kosc, Tanya Z [Rochester, NY; Marshall, Kenneth L [Rochester, NY; Jacobs, Stephen D [Pittsford, NY

    2006-05-09

    Optical devices utilizing flakes (also called platelets) suspended in a host fluid have optical characteristics, such as reflective properties, which are angular dependent in response to an AC field. The reflectivity may be Bragg-like, and the characteristics are obtained through the use of flakes of liquid crystal material, such as polymer liquid crystal (PLC) materials including polymer cholesteric liquid crystal (PCLC) and polymer nematic liquid crystal (PNLC) material or birefringent polymers (BP). The host fluid may be propylene carbonate, poly(ethylene glycol) or other fluids or fluid mixtures having fluid conductivity to support conductivity in the flake/host system. AC field dependent rotation of 90.degree. can be obtained at rates and field intensities dependent upon the frequency and magnitude of the AC field. The devices are useful in providing displays, polarizers, filters, spatial light modulators and wherever switchable polarizing, reflecting, and transmission properties are desired.

  11. 100-nm gate lithography for double-gate transistors

    Science.gov (United States)

    Krasnoperova, Azalia A.; Zhang, Ying; Babich, Inna V.; Treichler, John; Yoon, Jung H.; Guarini, Kathryn; Solomon, Paul M.

    2001-09-01

    The double gate field effect transistor (FET) is an exploratory device that promises certain performance advantages compared to traditional CMOS FETs. It can be scaled down further than the traditional devices because of the greater electrostatic control by the gates on the channel (about twice as short a channel length for the same gate oxide thickness), has steeper sub-threshold slope and about double the current for the same width. This paper presents lithographic results for double gate FET's developed at IBM's T. J. Watson Research Center. The device is built on bonded wafers with top and bottom gates self-aligned to each other. The channel is sandwiched between the top and bottom polysilicon gates and the gate length is defined using DUV lithography. An alternating phase shift mask was used to pattern gates with critical dimensions of 75 nm, 100 nm and 125 nm in photoresist. 50 nm gates in photoresist have also been patterned by 20% over-exposure of nominal 100 nm lines. No trim mask was needed because of a specific way the device was laid out. UV110 photoresist from Shipley on AR-3 antireflective layer were used. Process windows, developed and etched patterns are presented.

  12. A rigorous simulation based study of gate misalignment effects in gate engineered double-gate (DG) MOSFETs

    Science.gov (United States)

    Sarangi, Santunu; Bhushan, Shiv; Santra, Abirmoya; Dubey, Sarvesh; Jit, Satyabrata; Tiwari, Pramod Kumar

    2013-08-01

    The double-gate (DG) Metal-Oxide-Semiconductor Field-Effect-Transistors (MOSFETs) are the front runner among the sub-100 nm devices because both front and back gate of DG MOSFETs control the channel region simultaneously. However, alignment between the front and back gate is an issue of concern during fabrication because its influences are baleful for device performance. Further, the issue of alignment between front and back gates assumes greater seriousness for gate engineered DG MOSFETs, like double material double gate (DMDG) or triple material double gate (TMDG) MOSFETs for improving the device performance. In this paper, we present a numerical simulation based study on the effects of gate misalignment between the front and the back gate for gate engineered double-gate (DG) Metal-Oxide-Semiconductor Field-Effect-Transistors (MOSFETs). Both source side misalignment (SSM) and drain side misalignment (DSM) of different lengths in the back gate have been considered to investigate the effects of gate misalignment on device performance. In this context, an extensive simulation has been performed by a commercially available two-dimensional (2D) device simulator (ATLAS™, SILVACO Int.) to figure out the impacts of misalignment on device characteristics like surface potential, threshold voltage, drain-induced-barrier lowering (DIBL), subthreshold swing, subthreshold current, maximum drain current, transconductance and output conductance.

  13. Transfer-free graphene synthesis on sapphire by catalyst metal agglomeration technique and demonstration of top-gate field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Miyoshi, Makoto, E-mail: miyoshi.makoto@nitech.ac.jp; Arima, Yukinori; Kubo, Toshiharu; Egawa, Takashi [Research Center for Nano Device and Advanced Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Mizuno, Masaya [Research Center for Nano Device and Advanced Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan); Soga, Tetsuo [Department of Frontier Materials, Nagoya Institute of Technology, Nagoya 466-8555 (Japan)

    2015-08-17

    Transfer-free graphene synthesis was performed on sapphire substrates by using the catalyst metal agglomeration technique, and the graphene film quality was compared to that synthesized on sputtered SiO{sub 2}/Si substrates. Raman scattering measurements indicated that the graphene film on sapphire has better structural qualities than that on sputtered SiO{sub 2}/Si substrates. The cross-sectional transmission microscopic study also revealed that the film flatness was drastically improved by using sapphire substrates instead of sputtered SiO{sub 2}/Si substrates. These quality improvements seemed to be due the chemical and thermal stabilities of sapphire. Top-gate field-effect transistors were fabricated using the graphene films on sapphire, and it was confirmed that their drain current can be modulated with applied gate voltages. The maximum field-effect mobilities were estimated to be 720 cm{sup 2}/V s for electrons and 880 cm{sup 2}/V s for holes, respectively.

  14. Design and simulation of a novel E-mode GaN MIS-HEMT based on a cascode connection for suppression of electric field under gate and improvement of reliability

    Science.gov (United States)

    Li, Weiyi; Zhang, Zhili; Fu, Kai; Yu, Guohao; Zhang, Xiaodong; Sun, Shichuang; Song, Liang; Hao, Ronghui; Fan, Yaming; Cai, Yong; Zhang, Baoshun

    2017-07-01

    We proposed a novel AlGaN/GaN enhancement-mode (E-mode) high electron mobility transistor (HEMT) with a dual-gate structure and carried out the detailed numerical simulation of device operation using Silvaco Atlas. The dual-gate device is based on a cascode connection of an E-mode and a D-mode gate. The simulation results show that electric field under the gate is decreased by more than 70% compared to that of the conventional E-mode MIS-HEMTs (from 2.83 MV/cm decreased to 0.83 MV/cm). Thus, with the discussion of ionized trap density, the proposed dual-gate structure can highly improve electric field-related reliability, such as, threshold voltage stability. In addition, compared with HEMT with field plate structure, the proposed structure exhibits a simplified fabrication process and a more effective suppression of high electric field. Project supported by the Key Technologies Support Program of Jiangsu Province (No. BE2013002-2) and the National Key Scientific Instrument and Equipment Development Projects of China (No. 2013YQ470767).

  15. Design and simulation of a novel E-mode GaN MIS-HEMT based on a cascode connection for suppression of electric field under gate and improvement of reliability

    Institute of Scientific and Technical Information of China (English)

    Weiyi Li; Yong Cai; Baoshun Zhang; Zhili Zhang; Kai Fu; Guohao Yu; Xiaodong Zhang; Shichuang Sun; Liang Song; Ronghui Hao; Yaming Fan

    2017-01-01

    We proposed a novel AlGaN/GaN enhancement-mode (E-mode) high electron mobility transistor (HEMT) with a dual-gate structure and carried out the detailed numerical simulation of device operation using Silvaco Atlas.The dual-gate device is based on a cascode connection of an E-mode and a D-mode gate.The simulation results show that electric field under the gate is decreased by more than 70% compared to that of the conventional E-mode MIS-HEMTs (from 2.83 MV/cm decreased to 0.83 MV/cm).Thus,with the discussion of ionized trap density,the proposed dual-gate structure can highly improve electric field-related reliability,such as,threshold voltage stability.In addition,compared with HEMT with field plate structure,the proposed structure exhibits a simplified fabrication process and a more effective suppression of high electric field.

  16. Minimization of Gate-Induced Drain Leakage by Controlling Gate Underlap Length for Low-Standby-Power Operation of 20-nm-Level Four-Terminal Silicon-on-Insulator Fin-Shaped Field Effect Transistor

    Science.gov (United States)

    Seongjae Cho,; Shinichi O'uchi,; Kazuhiko Endo,; Takashi Matsukawa,; Kunihiro Sakamoto,; Yongxun Liu,; Byung-Gook Park,; Meishoku Masahara,

    2010-02-01

    Recently, gate-induced drain leakage (GIDL) has become a crucial factor of current characteristics as junction doping concentration becomes more abruptly graded owing to device scaling. It should be effectively suppressed for the low-standby-power operation of ultra small metal-oxide-semiconductor field effect transistor (MOSFET) devices. In this work, the appropriate underlap length range for the effective minimization of GIDL in 20-nm-level four-terminal (4-T) fin-shaped FET (FinFET) on silicon-on-insulator (SOI) is established. In order to identify the effect of underlap length on GIDL more precisely, the source and drain (S/D) junction doping profile and the majority/minority carrier lifetimes have been extracted by the measurement of a p-n junction test element group (TEG). The TEG was fabricated under the same process conditions that were used in forming the S/D junctions of 100-nm-level 4-T SOI FinFET in our previous research. The GIDL component in the off-state current is investigated with underlap length variation along with the inspection of basic current characteristics. For low-standby-power operation, an underlap junction is more desirable than an overlap junction, and the underlap length should be at least 10 nm to suppress GIDL effectively.

  17. Metrology solutions using optical scatterometry for advanced CMOS: III-V and Germanium multi-gate field-effect transistors

    Science.gov (United States)

    Chin, Hock-Chun; Liu, Bin; Zhang, Xingui; Ling, Moh-Lung; Yip, Chan-Hoe; Liu, Yongdong; Hu, Jiangtao; Yeo, Yee-Chia

    2013-04-01

    In this work, we report metrology solutions using scatterometry Optical Critical Dimension (OCD) characterization on two advanced CMOS devices: novel n-channel gate-last In0.53Ga0.47As FinFET with self-aligned Molybdenum (Mo) contacts and p-channel Ge FinFET formed on Germanium-on-Insulator (GOI) substrate. Key critical process steps during the fabrication of these advanced transistors were identified for process monitor using scatterometry OCD measurement to improve final yield. Excellent correlation with reference metrology and high measurement precision were achieved by using OCD characterization, confirming scatterometry OCD as a promising metrology technique for next generation device applications. In addition, we also further explore OCD characterization using normal incidence spectroscopic reflectometry (SR), oblique incidence spectroscopic ellipsometry (SE), and combined SR+SE technologies. The combined SR+SE approach was found to provide better precision.

  18. Effect of the Si nanowire's diameter and doping profile on the electrical characteristics of gate-all-around twin Si-nanowire field-effect transistors

    Science.gov (United States)

    Kim, Dong Hun; Kim, Tae Whan

    2015-08-01

    The effect of the Si nanowire's diameter and doping profile on the electrical characteristics of gate-all-around twin Si-nanowire field-effect transistors (TSNWFETs) was simulated by using the three-dimensional technology computer-aided design simulation tools of Sentaurus and taking into account quantum effects. While the switching and the short-channel immunity characteristics were improved with decreasing nanowire diameter, the threshold voltage and the total on-current for the TSNWFETs decreased, resulting in a deterioration of device performances. The swing characteristics for the TSNWFETs maintained almost the same behaviors regardless of the boron concentration variation in the nanowire. Gate-induced drain leakage (GIDL) of the TSNWFETs appeared at a high drain voltage, and the GIDL current increased with increasing boron concentration in the Si nanowires. The electrical characteristics of the TSNWFETs were improved by optimizing the diameter and the doping concentration of the Si nanowire to lower the GIDL and the off-state leakage current.

  19. Simulation study of 14-nm-gate III-V trigate field effect transistor devices with In1−xGaxAs channel capping layer

    Directory of Open Access Journals (Sweden)

    Cheng-Hao Huang

    2015-06-01

    Full Text Available In this work, we study characteristics of 14-nm-gate InGaAs-based trigate MOSFET (metal-oxide-semiconductor field effect transistor devices with a channel capping layer. The impacts of thickness and gallium (Ga concentration of the channel capping layer on the device characteristic are firstly simulated and optimized by using three-dimensional quantum-mechanically corrected device simulation. Devices with In1−xGaxAs/In0.53Ga0.47As channels have the large driving current owing to small energy band gap and low alloy scattering at the channel surface. By simultaneously considering various physical and switching properties, a 4-nm-thick In0.68Ga0.32As channel capping layer can be adopted for advanced applications. Under the optimized channel parameters, we further examine the effects of channel fin angle and the work-function fluctuation (WKF resulting from nano-sized metal grains of NiSi gate on the characteristic degradation and variability. To maintain the device characteristics and achieve the minimal variation induced by WKF, the physical findings of this study indicate a critical channel fin angle of 85o is needed for the device with an averaged grain size of NiSi below 4x4 nm2.

  20. Reading Gate Positions with a Smartphone

    Science.gov (United States)

    van Overloop, Peter-Jules; Hut, Rolf

    2015-04-01

    Worldwide many flow gates are built in water networks in order to direct water to appropriate locations. Most of these gates are adjusted manually by field operators of water management organizations and it is often centrally not known what the new position of the gate is. This makes centralized management of the entire water network difficult. One of the reasons why the measurement of the gate position is usually not executed, is that for certain gates it is not easy to do such a reading. Tilting weirs or radial gates are examples where operators need special equipment (measuring rod and long level) to determine the position and it could even be a risky procedure. Another issue is that once the measurement is done, the value is jotted down in a notebook and later, at the office, entered in a computer system. So the entire monitoring procedure is not real-time and prone to human errors. A new way of monitoring gate positions is introduced. It consists of a level that is attached to the gate and an app with which a picture can be taken from the level. Using dedicated pattern recognition algorithms, the gate position can be read by using the angle of the level versus reference points on the gate, the radius of that gate and the absolute level of the joint around which the gate turn. The method uses gps-localization of the smartphone to store the gate position in the right location in the central database.

  1. A Field Programmable Gate Array-Based Reconfigurable Smart-Sensor Network for Wireless Monitoring of New Generation Computer Numerically Controlled Machines

    Science.gov (United States)

    Moreno-Tapia, Sandra Veronica; Vera-Salas, Luis Alberto; Osornio-Rios, Roque Alfredo; Dominguez-Gonzalez, Aurelio; Stiharu, Ion; de Jesus Romero-Troncoso, Rene

    2010-01-01

    Computer numerically controlled (CNC) machines have evolved to adapt to increasing technological and industrial requirements. To cover these needs, new generation machines have to perform monitoring strategies by incorporating multiple sensors. Since in most of applications the online Processing of the variables is essential, the use of smart sensors is necessary. The contribution of this work is the development of a wireless network platform of reconfigurable smart sensors for CNC machine applications complying with the measurement requirements of new generation CNC machines. Four different smart sensors are put under test in the network and their corresponding signal processing techniques are implemented in a Field Programmable Gate Array (FPGA)-based sensor node. PMID:22163602

  2. Gate voltage dependent 1/f noise variance model based on physical noise generation mechanisms in n-channel metal-oxide-semiconductor field-effect transistors

    Science.gov (United States)

    Arai, Yukiko; Aoki, Hitoshi; Abe, Fumitaka; Todoroki, Shunichiro; Khatami, Ramin; Kazumi, Masaki; Totsuka, Takuya; Wang, Taifeng; Kobayashi, Haruo

    2015-04-01

    1/f noise is one of the most important characteristics for designing analog/RF circuits including operational amplifiers and oscillators. We have analyzed and developed a novel 1/f noise model in the strong inversion, saturation, and sub-threshold regions based on SPICE2 type model used in any public metal-oxide-semiconductor field-effect transistor (MOSFET) models developed by the University of California, Berkeley. Our model contains two noise generation mechanisms that are mobility and interface trap number fluctuations. Noise variability dependent on gate voltage is also newly implemented in our model. The proposed model has been implemented in BSIM4 model of a SPICE3 compatible circuit simulator. Parameters of the proposed model are extracted with 1/f noise measurements for simulation verifications. The simulation results show excellent agreements between measurement and simulations.

  3. GaN junctionless trigate field-effect transistor with deep-submicron gate length: Characterization and modeling in RF regime

    Science.gov (United States)

    Im, Ki-Sik; Seo, Jae Hwa; Yoon, Young Jun; In Jang, Young; Kim, Jin Su; Cho, Seongjae; Lee, Jae-Hoon; Cristoloveanu, Sorin; Lee, Jung-Hee; Kang, In Man

    2014-11-01

    Radio-frequency (RF) performances of a gallium nitride (GaN)-based junctionless (JL) trigate field-effect transistor (TGFET), or fin-shaped FET (FinFET), are demonstrated along with RF modeling for the first time. The fabricated GaN JL TGFET had a gate length of 350 nm and had no AlGaN/GaN heterojunction on which conventional high-mobility electron transistors (HEMTs) had been based to have a fully junctionless channel. The device with five fin channels exhibits a maximum drain current of 403 mA/mm and maximum transconductance of 123.6 mS/mm. The maximum cutoff frequency (fT) and maximum oscillation frequency (fmax) are 2.45 and 9.75 GHz, respectively. In order to confirm its potential for high-frequency applications, small-signal modeling has been carried out up to a frequency above the maximum fT.

  4. Fast contactless vibrating structure characterization using real time field programmable gate array-based digital signal processing: demonstrations with a passive wireless acoustic delay line probe and vision.

    Science.gov (United States)

    Goavec-Mérou, G; Chrétien, N; Friedt, J-M; Sandoz, P; Martin, G; Lenczner, M; Ballandras, S

    2014-01-01

    Vibrating mechanical structure characterization is demonstrated using contactless techniques best suited for mobile and rotating equipments. Fast measurement rates are achieved using Field Programmable Gate Array (FPGA) devices as real-time digital signal processors. Two kinds of algorithms are implemented on FPGA and experimentally validated in the case of the vibrating tuning fork. A first application concerns in-plane displacement detection by vision with sampling rates above 10 kHz, thus reaching frequency ranges above the audio range. A second demonstration concerns pulsed-RADAR cooperative target phase detection and is applied to radiofrequency acoustic transducers used as passive wireless strain gauges. In this case, the 250 ksamples/s refresh rate achieved is only limited by the acoustic sensor design but not by the detection bandwidth. These realizations illustrate the efficiency, interest, and potentialities of FPGA-based real-time digital signal processing for the contactless interrogation of passive embedded probes with high refresh rates.

  5. A Field Programmable Gate Array-Based Reconfigurable Smart-Sensor Network for Wireless Monitoring of New Generation Computer Numerically Controlled Machines

    Directory of Open Access Journals (Sweden)

    Ion Stiharu

    2010-08-01

    Full Text Available Computer numerically controlled (CNC machines have evolved to adapt to increasing technological and industrial requirements. To cover these needs, new generation machines have to perform monitoring strategies by incorporating multiple sensors. Since in most of applications the online Processing of the variables is essential, the use of smart sensors is necessary. The contribution of this work is the development of a wireless network platform of reconfigurable smart sensors for CNC machine applications complying with the measurement requirements of new generation CNC machines. Four different smart sensors are put under test in the network and their corresponding signal processing techniques are implemented in a Field Programmable Gate Array (FPGA-based sensor node.

  6. Cable suspended windmill

    Science.gov (United States)

    Farmer, Moses G. (Inventor)

    1990-01-01

    A windmill is disclosed which includes an airframe having an upwind end and a downwind end. The first rotor is rotatably connected to the airframe, and a generator is supported by the airframe and driven by the rotor. The airframe is supported vertically in an elevated disposition by poles which extend vertically upwardly from the ground and support cables which extend between the vertical poles. Suspension cables suspend the airframe from the support cable.

  7. Voltage-gated sodium channels: (NaV )igating the field to determine their contribution to visceral nociception.

    Science.gov (United States)

    Erickson, Andelain; Deiteren, Annemie; Harrington, Andrea M; Garcia-Caraballo, Sonia; Castro, Joel; Caldwell, Ashlee; Grundy, Luke; Brierley, Stuart M

    2018-01-09

    Chronic visceral pain, altered motility and bladder dysfunction are common, yet poorly managed symptoms of functional and inflammatory disorders of the gastrointestinal and urinary tracts. Recently, numerous human channelopathies of the voltage-gated sodium (NaV ) channel family have been identified, which induce either painful neuropathies, an insensitivity to pain, or alterations in smooth muscle function. The identification of these disorders, in addition to the recent utilisation of genetically modified NaV mice and specific NaV channel modulators, has shed new light on how NaV channels contribute to the function of neuronal and non-neuronal tissues within the gastrointestinal tract and bladder. Here we review the current pre-clinical and clinical evidence to reveal how the nine NaV channel family members (NaV 1.1 - NaV 1.9) contribute to abdominal visceral function in normal and disease states. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  8. A High-Speed Fully Digital Phase-Synchronizer Implemented in a Field Programmable Gate Array Device

    Directory of Open Access Journals (Sweden)

    Frankowski Robert

    2017-09-01

    Full Text Available Most systems used in quantum physics experiments require the efficient and simultaneous recording different multi-photon coincidence detection events. In such experiments, the single-photon gated counting systems can be applicable. The main sources of errors in these systems are both instability of the clock source and their imperfect synchronization with the excitation source. Below, we propose a solution for improvement of the metrological parameters of such measuring systems. Thus, we designed a novel integrated circuit dedicated to registration of signals from a photon number resolving detectors including a phase synchronizer module. This paper presents the architecture of a high-resolution (~60 ps digital phase synchronizer module cooperating with a multi-channel coincidence counter. The main characteristic feature of the presented system is its ability to fast synchronization (requiring only one clock period with the measuring process. Therefore, it is designed to work with various excitation sources of a very wide frequency range. Implementation of the phase synchronizer module in an FPGA device enabled to reduce the synchronization error value from 2.857 ns to 214.8 ps.

  9. A wave-resolving model for nearshore suspended sediment transport

    Science.gov (United States)

    Ma, Gangfeng; Chou, Yi-Ju; Shi, Fengyan

    2014-05-01

    This paper presents a wave-resolving sediment transport model, which is capable of simulating sediment suspension in the field-scale surf zone. The surf zone hydrodynamics is modeled by the non-hydrostatic model NHWAVE (Ma et al., 2012). The turbulent flow and suspended sediment are simulated in a coupled manner. Three effects of suspended sediment on turbulent flow field are considered: (1) baroclinic forcing effect; (2) turbulence damping effect and (3) bottom boundary layer effect. Through the validation with the laboratory measurements of suspended sediment under nonbreaking skewed waves and surfzone breaking waves, we demonstrate that the model can reasonably predict wave-averaged sediment profiles. The model is then utilized to simulate a rip current field experiment (RCEX) and nearshore suspended sediment transport. The offshore sediment transport by rip currents is captured by the model. The effects of suspended sediment on self-suspension are also investigated. The turbulence damping and bottom boundary layer effects are significant on sediment suspension. The suspended sediment creates a stably stratified water column, damping fluid turbulence and reducing turbulent diffusivity. The suspension of sediment also produces a stably stratified bottom boundary layer. Thus, the drag coefficient and bottom shear stress are reduced, causing less sediment pickup from the bottom. The cross-shore suspended sediment flux is analyzed as well. The mean Eulerian suspended sediment flux is shoreward outside the surf zone, while it is seaward in the surf zone.

  10. Enhancement of the saturation mobility in a ferroelectric-gated field-effect transistor by the surface planarization of ferroelectric film

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Woo Young, E-mail: semigumi@kaist.ac.kr [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Jeon, Gwang-Jae; Kang, In-Ku; Shim, Hyun Bin; Lee, Hee Chul [Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2015-09-30

    Ferroelectricity refers to the property of a dielectric material to undergo spontaneous polarization which originates from the crystalline phase. Hence, ferroelectric materials have a certain degree of surface roughness when they are formed as a thin film. A high degree of surface roughness may cause unintended phenomena when the ferroelectric material is used in electronic devices. Specifically, the quality of subsequently deposited film could be affected by the rough surface. The present study reports that the surface roughness of ferroelectric polymer film can be reduced by a double-spin-coating method of a solution, with control of the solubility of the solution. At an identical thickness of 350 nm, double-spin-coated ferroelectric film has a root-mean-square roughness of only 3 nm, while for single-spin-coated ferroelectric film this value is approximately 16 nm. A ferroelectric-gated field-effect transistor was fabricated using the proposed double-spin-coating method, showing a maximum saturation mobility as much as seven-fold than that of a transistor fabricated with single-spin-coated ferroelectric film. The enhanced saturation mobility could be explained by the Poole–Frenkel conduction mechanism. The proposed method to reduce the surface roughness of ferroelectric film would be useful for high performance organic electronic devices, including crystalline-phase dielectric film. - Highlights: • Single and double-layer solution-processed polymer ferroelectric films were obtained. • Adjusting the solvent solubility allows making double-layer ferroelectric (DF) films. • The DF film has a smoother surface than single-layer ferroelectric (SF) film. • DF-gated transistor has faster saturation mobility than SF-based transistor. • Solvent solubility adjustment led to higher performance organic devices.

  11. Investigation of Low-Energy Tilted Ion Implantation for Fin-Type Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor Extension Doping

    Science.gov (United States)

    Yongxun Liu,; Takashi Matsukawa,; Kazuhiko Endo,; Shinich O'uchi,; Kunihiro Sakamoto,; Junichi Tsukada,; Yuki Ishikawa,; Hiromi Yamauchi,; Meishoku Masahara,

    2010-04-01

    The low-energy tilted ion implantation (I/I) for fin-type double-gate metal-oxide-semiconductor field-effect transistor (FinFET) source-drain (SD) extension doping is systematically investigated experimentally by fabricating a series of n+-polycrystalline silicon (poly-Si) gate n-channel FinFETs under different I/I conditions. The on-state current (ION) versus off-state current (IOFF) and the SD parasitic resistance (Rp) are used for benchmarking the performance of the fabricated devices to investigate the optimal extension I/I conditions, including dose (D) and tilted angle (θ), at a fixed low energy of 5 keV. It is experimentally found that the best extension I/I conditions are D = 4× 1014 cm-2 and θ = 60°. With further increasing D, the device performance deteriorates owing to the incomplete recrystallization of amorphous regions in the thin extension regions. In the case of θ = 0°, marked increment and fluctuations in Rp are observed because the implant atoms scatter out randomly from each extension region. The Rp value of the FinFETs fabricated under the above best I/I conditions is comparable to that of devices fabricated by the solid-phase diffusion of phosphors from phosphosilicate glass (PSG). This indicates that the extension I/I conditions of D = 4× 1014 cm-2 and θ = 60° are almost optimal and is very effective for high-performance FinFET fabrication.

  12. Retrieval of Chlorophyll-a and Total Suspended Solids Using Iterative Stepwise Elimination Partial Least Squares (ISE-PLS Regression Based on Field Hyperspectral Measurements in Irrigation Ponds in Higashihiroshima, Japan

    Directory of Open Access Journals (Sweden)

    Zuomin Wang

    2017-03-01

    Full Text Available Concentrations of chlorophyll-a (Chl-a and total suspended solids (TSS are significant parameters used to assess water quality. The objective of this study is to establish a quantitative model for estimating the Chl-a and the TSS concentrations in irrigation ponds in Higashihiroshima, Japan, using field hyperspectral measurements and statistical analysis. Field experiments were conducted in six ponds and spectral readings for Chl-a and TSS were obtained from six field observations in 2014. For statistical approaches, we used two spectral indices, the ratio spectral index (RSI and the normalized difference spectral index (NDSI, and a partial least squares (PLS regression. The predictive abilities were compared using the coefficient of determination (R2, the root mean squared error of cross validation (RMSECV and the residual predictive deviation (RPD. Overall, iterative stepwise elimination based on PLS (ISE–PLS, using the first derivative reflectance (FDR, showed the best predictive accuracy, for both Chl-a (R2 = 0.98, RMSECV = 6.15, RPD = 7.44 and TSS (R2 = 0.97, RMSECV = 1.91, RPD = 6.64. The important wavebands for estimating Chl-a (16.97% of all wavebands and TSS (8.38% of all wavebands were selected by ISE–PLS from all 501 wavebands over the 400–900 nm range. These findings suggest that ISE–PLS based on field hyperspectral measurements can be used to estimate water Chl-a and TSS concentrations in irrigation ponds.

  13. Gate-Bias Controlled Charge Trapping as a Mechanism for NO2 Detection with Field-Effect Transistors

    NARCIS (Netherlands)

    Andringa, Anne-Marije; Meijboom, Juliaan R.; Smits, Edsger C. P.; Mathijssen, Simon G. J.; Blom, Paul W. M.; de Leeuw, Dago M.

    2011-01-01

    Detection of nitrogen dioxide, NO2, is required to monitor the air-quality for human health and safety. Commercial sensors are typically chemiresistors, however field-effect transistors are being investigated. Although numerous investigations have been reported, the NO2 sensing mechanism is not

  14. Gate-bias controlled charge trapping as a mechanism for NO2 detection with field-effect transistors

    NARCIS (Netherlands)

    Andringa, A.-M.; Meijboom, J.R.; Smits, E.C.P.; Mathijssen, S.G.J.; Blom, P.W.M.; Leeuw, D.M. de

    2011-01-01

    Detection of nitrogen dioxide, NO2, is required to monitor the air-quality for human health and safety. Commercial sensors are typically chemiresistors, however field-effect transistors are being investigated. Although numerous investigations have been reported, the NO2 sensing mechanism is not

  15. Controlling of the surface energy of the gate dielectric in organic field-effect transistors by polymer blend

    NARCIS (Netherlands)

    Gao, Jia; Asadi, Kamal; Xu, Jian Bin; An, Jin

    2009-01-01

    In this letter, we demonstrate that by blending insulating polymers, one can fabricate an insulating layer with controllable surface energy for organic field-effect transistors. As a model system, we used copper phthalocyanine evaporated on layers of polymethyl metacrylate blended with polystyrene

  16. Dispersive suspended microextraction.

    Science.gov (United States)

    Yang, Zhong-Hua; Liu, Yu; Lu, Yue-Le; Wu, Tong; Zhou, Zhi-Qiang; Liu, Dong-Hui

    2011-11-14

    A novel sample pre-treatment technique termed dispersive suspended microextraction (DSME) coupled with gas chromatography-flame photometric detection (GC-FPD) has been developed for the determination of eight organophosphorus pesticides (ethoprophos, malathion, chlorpyrifos, isocarbophos, methidathion, fenamiphos, profenofos, triazophos) in aqueous samples. In this method, both extraction and two phases' separation process were performed by the assistance of magnetic stirring. After separating the two phases, 1 μL of the suspended phase was injected into GC for further instrument analysis. Varieties of experiment factors which could affect the experiment results were optimized and the following were selected: 12.0 μL p-xylene was selected as extraction solvent, extraction speed was 1200 rpm, extraction time was 30 s, the restoration speed was 800 rpm, the restoration time was 8 min, and no salt was added. Under the optimum conditions, limits of detections (LODs) varied between 0.01 and 0.05 μg L(-1). The relative standard deviation (RSDs, n=6) ranged from 4.6% to 12.1%. The linearity was obtained by five points in the concentration range of 0.1-100.0 μg L(-1). Correlation coefficients (r) varied from 0.9964 to 0.9995. The enrichment factors (EFs) were between 206 and 243. In the final experiment, the developed method has been successfully applied to the determination of organophosphorus pesticides in wine and tap water samples and the obtained recoveries were between 83.8% and 101.3%. Compared with other pre-treatment methods, DSME has its own features and could achieve satisfied results for the analysis of trace components in complicated matrices. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. A versatile LabVIEW and field-programmable gate array-based scanning probe microscope for in operando electronic device characterization.

    Science.gov (United States)

    Berger, Andrew J; Page, Michael R; Jacob, Jan; Young, Justin R; Lewis, Jim; Wenzel, Lothar; Bhallamudi, Vidya P; Johnston-Halperin, Ezekiel; Pelekhov, Denis V; Hammel, P Chris

    2014-12-01

    Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In operando characterization of such devices by scanning probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanning probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field-programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform the various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically biased graphene field-effect transistor device. The combination of SPM and electrical transport also enables imaging of the transport response to a localized perturbation provided by the scanned cantilever tip. Facilitated by the broad presence of LabVIEW in the experimental sciences and the openness of our software solution, our system permits a wide variety of combined scanning and transport measurements by providing standardized interfaces and flexible access to all aspects of a measurement (input and output signals, and processed data). Our system also enables precise control of timing (synchronization of scanning and transport operations) and implementation of sophisticated feedback protocols, and thus should be broadly interesting and useful to practitioners in the field.

  18. A versatile LabVIEW and field-programmable gate array-based scanning probe microscope for in operando electronic device characterization

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Andrew J., E-mail: berger.156@osu.edu; Page, Michael R.; Young, Justin R.; Bhallamudi, Vidya P.; Johnston-Halperin, Ezekiel; Pelekhov, Denis V.; Hammel, P. Chris [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States); Jacob, Jan [Werum Software and Systems CIS AG, Wulf-Werum-Straße 3, 21337 Lüneburg (Germany); Lewis, Jim; Wenzel, Lothar [National Instruments, Austin, Texas 78759 (United States)

    2014-12-15

    Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In operando characterization of such devices by scanning probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanning probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field-programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform the various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically biased graphene field-effect transistor device. The combination of SPM and electrical transport also enables imaging of the transport response to a localized perturbation provided by the scanned cantilever tip. Facilitated by the broad presence of LabVIEW in the experimental sciences and the openness of our software solution, our system permits a wide variety of combined scanning and transport measurements by providing standardized interfaces and flexible access to all aspects of a measurement (input and output signals, and processed data). Our system also enables precise control of timing (synchronization of scanning and transport operations) and implementation of sophisticated feedback protocols, and thus should be broadly interesting and useful to practitioners in the field.

  19. A versatile LabVIEW and field-programmable gate array-based scanning probe microscope for in operando electronic device characterization

    Science.gov (United States)

    Berger, Andrew J.; Page, Michael R.; Jacob, Jan; Young, Justin R.; Lewis, Jim; Wenzel, Lothar; Bhallamudi, Vidya P.; Johnston-Halperin, Ezekiel; Pelekhov, Denis V.; Hammel, P. Chris

    2014-12-01

    Understanding the complex properties of electronic and spintronic devices at the micro- and nano-scale is a topic of intense current interest as it becomes increasingly important for scientific progress and technological applications. In operando characterization of such devices by scanning probe techniques is particularly well-suited for the microscopic study of these properties. We have developed a scanning probe microscope (SPM) which is capable of both standard force imaging (atomic, magnetic, electrostatic) and simultaneous electrical transport measurements. We utilize flexible and inexpensive FPGA (field-programmable gate array) hardware and a custom software framework developed in National Instrument's LabVIEW environment to perform the various aspects of microscope operation and device measurement. The FPGA-based approach enables sensitive, real-time cantilever frequency-shift detection. Using this system, we demonstrate electrostatic force microscopy of an electrically biased graphene field-effect transistor device. The combination of SPM and electrical transport also enables imaging of the transport response to a localized perturbation provided by the scanned cantilever tip. Facilitated by the broad presence of LabVIEW in the experimental sciences and the openness of our software solution, our system permits a wide variety of combined scanning and transport measurements by providing standardized interfaces and flexible access to all aspects of a measurement (input and output signals, and processed data). Our system also enables precise control of timing (synchronization of scanning and transport operations) and implementation of sophisticated feedback protocols, and thus should be broadly interesting and useful to practitioners in the field.

  20. Near interface traps in SiO{sub 2}/4H-SiC metal-oxide-semiconductor field effect transistors monitored by temperature dependent gate current transient measurements

    Energy Technology Data Exchange (ETDEWEB)

    Fiorenza, Patrick; La Magna, Antonino; Vivona, Marilena; Roccaforte, Fabrizio [Consiglio Nazionale delle Ricerche-Istituto per la Microelettronica e Microsistemi (CNR-IMM), Strada VIII 5, Zona Industriale 95121 Catania (Italy)

    2016-07-04

    This letter reports on the impact of gate oxide trapping states on the conduction mechanisms in SiO{sub 2}/4H-SiC metal-oxide-semiconductor field effect transistors (MOSFETs). The phenomena were studied by gate current transient measurements, performed on n-channel MOSFETs operated in “gate-controlled-diode” configuration. The measurements revealed an anomalous non-steady conduction under negative bias (V{sub G} > |20 V|) through the SiO{sub 2}/4H-SiC interface. The phenomenon was explained by the coexistence of a electron variable range hopping and a hole Fowler-Nordheim (FN) tunnelling. A semi-empirical modified FN model with a time-depended electric field is used to estimate the near interface traps in the gate oxide (N{sub trap} ∼ 2 × 10{sup 11} cm{sup −2}).

  1. Implementation of sub-nanosecond time-to-digital convertor in field-programmable gate array: applications to time-of-flight analysis in muon radiography

    Science.gov (United States)

    Marteau, Jacques; de Bremond d'Ars, Jean; Gibert, Dominique; Jourde, Kevin; Gardien, Serge; Girerd, Claude; Ianigro, Jean-Christophe

    2014-03-01

    Time-of-flight (TOF) techniques are standard techniques in high energy physics to determine particles’ propagation directions. Since particle velocities are generally close to c, the speed of light, and detector typical dimensions at the metre level, the state-of-the-art TOF techniques should reach sub-nanosecond timing resolution. Among the various techniques already available, the recently developed ring oscillator time-to-digital converter (TDC) ones, implemented in low-cost programmable logic circuits like FPGA (field programmable gate array), feature a very interesting figure of merit since a very good timing performance may be achieved with limited processing resources. This issue is relevant for applications where unmanned sensors should have the lowest possible power consumption. Actually this paper describes in detail the application of this kind of TOF technique to muon tomography of geological bodies. Muon tomography aims at measuring density variations and absolute densities through the detection of atmospheric muon flux’s attenuation, due to the presence of matter. When the measured fluxes become very low, an identified source of noise comes from backwards propagating particles hitting the detector in a direction pointing to the geological body. The separation between through-going and backward-going particles on the basis of the TOF information is therefore a key parameter for the tomography analysis and subsequent forecasts. This paper describes a TDC implementation fulfilling the requirements of a TOF measurement applied to muon tomography.

  2. Nonvolatile ferroelectric memory based on PbTiO3 gated single-layer MoS2 field-effect transistor

    Science.gov (United States)

    Shin, Hyun Wook; Son, Jong Yeog

    2017-10-01

    We fabricated ferroelectric non-volatile random access memory (FeRAM) based on a field effect transistor (FET) consisting of a monolayer MoS2 channel and a ferroelectric PbTiO3 (PTO) thin film of gate insulator. An epitaxial PTO thin film was deposited on a Nb-doped SrTiO3 (Nb:STO) substrate via pulsed laser deposition. A monolayer MoS2 sheet was exfoliated from a bulk crystal and transferred to the surface of the PTO/Nb:STO. Structural and surface properties of the PTO thin film were characterized by X-ray diffraction and atomic force microscopy, respectively. Raman spectroscopy analysis was performed to identify the single-layer MoS2 sheet on the PTO/Nb:STO. We obtained mobility value (327 cm2/V·s) of the MoS2 channel at room temperature. The MoS2-PTO FeRAM FET showed a wide memory window with 17 kΩ of resistance variation which was attributed to high remnant polarization of the epitaxially grown PTO thin film. According to the fatigue resistance test for the FeRAM FET, however, the resistance states gradually varied during the switching cycles of 109.[Figure not available: see fulltext.

  3. Mitigation of cache memory using an embedded hard-core PPC440 processor in a Virtex-5 Field Programmable Gate Array.

    Energy Technology Data Exchange (ETDEWEB)

    Learn, Mark Walter

    2010-02-01

    Sandia National Laboratories is currently developing new processing and data communication architectures for use in future satellite payloads. These architectures will leverage the flexibility and performance of state-of-the-art static-random-access-memory-based Field Programmable Gate Arrays (FPGAs). One such FPGA is the radiation-hardened version of the Virtex-5 being developed by Xilinx. However, not all features of this FPGA are being radiation-hardened by design and could still be susceptible to on-orbit upsets. One such feature is the embedded hard-core PPC440 processor. Since this processor is implemented in the FPGA as a hard-core, traditional mitigation approaches such as Triple Modular Redundancy (TMR) are not available to improve the processor's on-orbit reliability. The goal of this work is to investigate techniques that can help mitigate the embedded hard-core PPC440 processor within the Virtex-5 FPGA other than TMR. Implementing various mitigation schemes reliably within the PPC440 offers a powerful reconfigurable computing resource to these node-based processing architectures. This document summarizes the work done on the cache mitigation scheme for the embedded hard-core PPC440 processor within the Virtex-5 FPGAs, and describes in detail the design of the cache mitigation scheme and the testing conducted at the radiation effects facility on the Texas A&M campus.

  4. Understanding radiation effects in SRAM-based field programmable gate arrays for implementing instrumentation and control systems of nuclear power plants

    Directory of Open Access Journals (Sweden)

    T.S. Nidhin

    2017-12-01

    Full Text Available Field programmable gate arrays (FPGAs are getting more attention in safety-related and safety-critical application development of nuclear power plant instrumentation and control systems. The high logic density and advancements in architectural features make static random access memory (SRAM-based FPGAs suitable for complex design implementations. Devices deployed in the nuclear environment face radiation particle strike that causes transient and permanent failures. The major reasons for failures are total ionization dose effects, displacement damage dose effects, and single event effects. Different from the case of space applications, soft errors are the major concern in terrestrial applications. In this article, a review of radiation effects on FPGAs is presented, especially soft errors in SRAM-based FPGAs. Single event upset (SEU shows a high probability of error in the dependable application development in FPGAs. This survey covers the main sources of radiation and its effects on FPGAs, with emphasis on SEUs as well as on the measurement of radiation upset sensitivity and irradiation experimental results at various facilities. This article also presents a comparison between the major SEU mitigation techniques in the configuration memory and user logics of SRAM-based FPGAs.

  5. Nonvolatile ferroelectric memory based on PbTiO3 gated single-layer MoS2 field-effect transistor

    Science.gov (United States)

    Shin, Hyun Wook; Son, Jong Yeog

    2018-01-01

    We fabricated ferroelectric non-volatile random access memory (FeRAM) based on a field effect transistor (FET) consisting of a monolayer MoS2 channel and a ferroelectric PbTiO3 (PTO) thin film of gate insulator. An epitaxial PTO thin film was deposited on a Nb-doped SrTiO3 (Nb:STO) substrate via pulsed laser deposition. A monolayer MoS2 sheet was exfoliated from a bulk crystal and transferred to the surface of the PTO/Nb:STO. Structural and surface properties of the PTO thin film were characterized by X-ray diffraction and atomic force microscopy, respectively. Raman spectroscopy analysis was performed to identify the single-layer MoS2 sheet on the PTO/Nb:STO. We obtained mobility value (327 cm2/V·s) of the MoS2 channel at room temperature. The MoS2-PTO FeRAM FET showed a wide memory window with 17 kΩ of resistance variation which was attributed to high remnant polarization of the epitaxially grown PTO thin film. According to the fatigue resistance test for the FeRAM FET, however, the resistance states gradually varied during the switching cycles of 109. [Figure not available: see fulltext.

  6. A Field-Programmable Gate Array (FPGA) TDC for the Fermilab SeaQuest (E906) Experiment and Its Test with a Novel External Wave Union Launcher

    Science.gov (United States)

    Wang, Su-Yin; Wu, Jinyuan; Yao, Shi-Hong; Chang, Wen-Chen

    2014-12-01

    We developed a field-programmable gate array (FPGA) TDC module for the tracking detectors of the Fermilab SeaQuest (E906) experiment, including drift chambers, proportional tubes, and hodoscopes. This 64-channel TDC module had a 6U VMEbus form factor and was equipped with a low-power, radiation-hardened Microsemi ProASIC3 Flash-based FPGA. The design of the new FPGA firmware (Run2-TDC) aimed to reduce the data volume and data acquisition (DAQ) deadtime. The firmware digitized multiple input hits of both polarities while allowing users to turn on a multiple-hit elimination logic to remove after-pulses in the wire chambers and proportional tubes. A scaler was implemented in the firmware to allow for recording the number of hits in each channel. The TDC resolution was determined by an internal cell delay of 450 ps. A measurement precision of 200 ps was achieved. We used five kinds of tests to ensure the qualification of 93 TDCs in mass production. We utilized the external wave union launcher in our test to improve the TDC's measurement precision and also to illustrate how to construct the Wave Union TDC using an existing multi-hit TDC without modifying its firmware. Measurement precision was improved by a factor of about two (108 ps) based on the four-edge wave union. Better measurement precision (69 ps) was achieved by combining the approaches of Wave Union TDC and multiple-channel ganging.

  7. Reconfigurable Ion Gating of 2H-MoTe2 Field-Effect Transistors Using Poly(ethylene oxide)-CsClO4 Solid Polymer Electrolyte.

    Science.gov (United States)

    Xu, Huilong; Fathipour, Sara; Kinder, Erich W; Seabaugh, Alan C; Fullerton-Shirey, Susan K

    2015-05-26

    Transition metal dichalcogenides are relevant for electronic devices owing to their sizable band gaps and absence of dangling bonds on their surfaces. For device development, a controllable method for doping these materials is essential. In this paper, we demonstrate an electrostatic gating method using a solid polymer electrolyte, poly(ethylene oxide) and CsClO4, on exfoliated, multilayer 2H-MoTe2. The electrolyte enables the device to be efficiently reconfigured between n- and p-channel operation with ON/OFF ratios of approximately 5 decades. Sheet carrier densities as high as 1.6 × 10(13) cm(-2) can be achieved because of a large electric double layer capacitance (measured as 4 μF/cm(2)). Further, we show that an in-plane electric field can be used to establish a cation/anion transition region between source and drain, forming a p-n junction in the 2H-MoTe2 channel. This junction is locked in place by decreasing the temperature of the device below the glass transition temperature of the electrolyte. The ideality factor of the p-n junction is 2.3, suggesting that the junction is recombination dominated.

  8. Characteristics of Extended-Gate Field-Effect Transistor (EGFET) Based on Porous n-Type (111) Silicon for Use in pH Sensors

    Science.gov (United States)

    Ahmed, Naser M.; Kabaa, E. A.; Jaafar, M. S.; Omar, A. F.

    2017-10-01

    Following the advances in pH sensors based on porous silicon (p-Si) in the late 20th century, several studies have been carried out to take advantage of the intrinsic properties of p-Si for development of chemical sensors. This study investigates the characteristics and pH sensitivity of an extended-gate field-effect transistor (EGFET) based on n-type p-Si with (111) orientation. Porous silicon was applied directly without coating. The x-ray diffractogram revealed only n-type (111) crystal orientation. p-Si was comparatively analyzed against a silicon wafer (flat and porous surface) in the pH range from 2 to 12. Regarding EGFET operation, p-Si exhibited significantly enhanced pH sensitivity of 56.13 mV/pH and linearity of 0.9857 (at drain-source current I DS of 0.1 mA, temperature of 300 K, and immersion time of 300 s) because of its high surface area, whereas the silicon wafer (flat and porous surface) exhibited comparatively poor sensitivity of 25.41 mV/pH and linearity of 0.99 under similar conditions. In addition, we demonstrate use of current as a second parameter with high linearity for pH sensing. The low hysteresis depth (9 mV) of the EGFET sensor based on p-Si indicates good stability and reversibility.

  9. Dynamic transport of suspended sediment by solitary wave: Experimental study

    Science.gov (United States)

    cho, JaeNam; Kim, DongHyun; Hwang, KyuNam; Lee, SeungOh

    2016-04-01

    Solitary waves are able to transport a large amount of suspended sediment when approaching on the beach, which sometimes causes - serious beach erosion, especially in the east and south coastal lines in Korea. But it has rarely been known about the method how to evaluate or estimate the amount of beach erosion caused by solitary waves. Experimental assessment is necessary to comprehend the process of sediment transport on a slope. The prismatic rectangular channel is 12 m long, 0.8 m wide, and 0.75 m high. A sluice gate is applied at prismatic channel in order to produce the solitary waves. Upstream water depth is more than channel water depth and the sluice gate is suddenly opened to simulate conditions of solitary waves. A sand slope with a 1/6 and a sediment thickness is 0.03 m. The experimental sediments are used anthracite (d_50=1.547 mm ,C_u=1.38) and Jumoonjin sand (d_50=0.627 mm ,C_u=1.68). Specific laboratory equipment are designed to collect suspended sediment samples at the same time along the wave propagation at 5 points with evenly space. Each amount of sampling is approximately 25 ml and they are completely dried in oven over 24 hours according to the USGS (Guideline and standard techniques and method 3-C4). Two video cameras (Model No. : Sony, HDR-XR550) are mounted for capturing images at top and side-view when the processes of solitary wave and run up/down on slope. Also, this study are analyzed the correlation between Suspended sediment concentration and turbidity. Also, this study are analyzed the correlation between suspended sediment concentration and turbidity. Turbidity is used to verify suspended sediment concentration. Dimensionless analyses of experimental results carried out in this study. One dimensionless parameter is expressed with pressure of solitary wave on a slope to suspended sediment concentration, which is concerned about lifting force. The other is relate to drag force presenting with run up/down velocity on a slope and

  10. Design, analysis and control of cable-suspended parallel robots and its applications

    CERN Document Server

    Zi, Bin

    2017-01-01

    This book provides an essential overview of the authors’ work in the field of cable-suspended parallel robots, focusing on innovative design, mechanics, control, development and applications. It presents and analyzes several typical mechanical architectures of cable-suspended parallel robots in practical applications, including the feed cable-suspended structure for super antennae, hybrid-driven-based cable-suspended parallel robots, and cooperative cable parallel manipulators for multiple mobile cranes. It also addresses the fundamental mechanics of cable-suspended parallel robots on the basis of their typical applications, including the kinematics, dynamics and trajectory tracking control of the feed cable-suspended structure for super antennae. In addition it proposes a novel hybrid-driven-based cable-suspended parallel robot that uses integrated mechanism design methods to improve the performance of traditional cable-suspended parallel robots. A comparative study on error and performance indices of hybr...

  11. Finite Element Modelling of a Field-Sensed Magnetic Suspended System for Accurate Proximity Measurement Based on a Sensor Fusion Algorithm with Unscented Kalman Filter.

    Science.gov (United States)

    Chowdhury, Amor; Sarjaš, Andrej

    2016-09-15

    The presented paper describes accurate distance measurement for a field-sensed magnetic suspension system. The proximity measurement is based on a Hall effect sensor. The proximity sensor is installed directly on the lower surface of the electro-magnet, which means that it is very sensitive to external magnetic influences and disturbances. External disturbances interfere with the information signal and reduce the usability and reliability of the proximity measurements and, consequently, the whole application operation. A sensor fusion algorithm is deployed for the aforementioned reasons. The sensor fusion algorithm is based on the Unscented Kalman Filter, where a nonlinear dynamic model was derived with the Finite Element Modelling approach. The advantage of such modelling is a more accurate dynamic model parameter estimation, especially in the case when the real structure, materials and dimensions of the real-time application are known. The novelty of the paper is the design of a compact electro-magnetic actuator with a built-in low cost proximity sensor for accurate proximity measurement of the magnetic object. The paper successively presents a modelling procedure with the finite element method, design and parameter settings of a sensor fusion algorithm with Unscented Kalman Filter and, finally, the implementation procedure and results of real-time operation.

  12. Finite Element Modelling of a Field-Sensed Magnetic Suspended System for Accurate Proximity Measurement Based on a Sensor Fusion Algorithm with Unscented Kalman Filter

    Science.gov (United States)

    Chowdhury, Amor; Sarjaš, Andrej

    2016-01-01

    The presented paper describes accurate distance measurement for a field-sensed magnetic suspension system. The proximity measurement is based on a Hall effect sensor. The proximity sensor is installed directly on the lower surface of the electro-magnet, which means that it is very sensitive to external magnetic influences and disturbances. External disturbances interfere with the information signal and reduce the usability and reliability of the proximity measurements and, consequently, the whole application operation. A sensor fusion algorithm is deployed for the aforementioned reasons. The sensor fusion algorithm is based on the Unscented Kalman Filter, where a nonlinear dynamic model was derived with the Finite Element Modelling approach. The advantage of such modelling is a more accurate dynamic model parameter estimation, especially in the case when the real structure, materials and dimensions of the real-time application are known. The novelty of the paper is the design of a compact electro-magnetic actuator with a built-in low cost proximity sensor for accurate proximity measurement of the magnetic object. The paper successively presents a modelling procedure with the finite element method, design and parameter settings of a sensor fusion algorithm with Unscented Kalman Filter and, finally, the implementation procedure and results of real-time operation. PMID:27649197

  13. 49 CFR 234.255 - Gate arm and gate mechanism.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm and gate mechanism. 234.255 Section 234... Maintenance, Inspection, and Testing Inspections and Tests § 234.255 Gate arm and gate mechanism. (a) Each gate arm and gate mechanism shall be inspected at least once each month. (b) Gate arm movement shall be...

  14. Study of fully-depleted Ge double-gate n-type Tunneling Field-Effect Transistors for improvement in on-state current and sub-threshold swing

    Science.gov (United States)

    Liu, Xiangyu; Hu, Huiyong; Wang, Meng; Zhang, Heming; Cui, Shimin; Shu, Bin; Wang, Bin

    2018-01-01

    In this paper, a fully-depleted (FD) Ge double-gate (DG) n-type Tunneling Field-Effect Transistors (TFET) structure is studied in detail by two-dimensional numerical simulation. The simulation results indicated that the on-state current Ion and on-off ratio of the FD Ge DG-TFET increases about 1 order of magnitude comparing with the Conventional Ge DG-TFET, and Ion=3.95×10-5 A/μm and the below 60 mV/decade subthreshold swing S=26.4 mV/decade are achieved with the length of gate LD=20 nm, the workfuntion of metal gate Φm=0.2 eV and the doping concentration of n+-type-channel ND=1×1018 cm-3. Moreover, the impacts of Φm, ND and LD are investigated. The simulation results indicated that the off-state current Ioff includes the tunneling current at the middle of channel IB the gated-induced drain leakage (GIDL) current IGIDL. With optimized Φm and ND, Ioff is reduced about 2 orders of magnitude to 2.5×10-13 A/μm with LD increasing from 40 nm to 100 nm, and on-off ratio is increased to 1.58×107.

  15. Microscale Digital Vacuum Electronic Gates

    Science.gov (United States)

    Manohara, Harish (Inventor); Mojarradi, Mohammed M. (Inventor)

    2014-01-01

    Systems and methods in accordance with embodiments of the invention implement microscale digital vacuum electronic gates. In one embodiment, a microscale digital vacuum electronic gate includes: a microscale field emitter that can emit electrons and that is a microscale cathode; and a microscale anode; where the microscale field emitter and the microscale anode are disposed within at least a partial vacuum; where the microscale field emitter and the microscale anode are separated by a gap; and where the potential difference between the microscale field emitter and the microscale anode is controllable such that the flow of electrons between the microscale field emitter and the microscale anode is thereby controllable; where when the microscale anode receives a flow of electrons, a first logic state is defined; and where when the microscale anode does not receive a flow of electrons, a second logic state is defined.

  16. Visual analysis of ductility/brittleness of welding fracture points on charpy test specimens using graphical blocks on field programmable gate arrays

    Science.gov (United States)

    Tickle, Andrew J.; Camargo-Rodriguez, Anyela; Smith, Jeremy S.

    2008-09-01

    The charpy impact is a technique used to evaluate the toughness of an engineering material that determines the amount of energy absorbed by it during fracture. Initially, measurements were estimated manually and later replaced by a PC version. This study reports the development of the Field Programmable Gate Array (FPGA) portable version. The FPGA based version allows easy analysis of samples without the need of sending them to a lab for analysis. The process, presented here, as the original, is based on measuring the percent of crystal in the test sample after impact, to determine if the material is ductile or brittle. The FPGA version, adapted under the MATLAB Simulink environment, shows a graphical block representation of the charpy impact PC version. An important asset of the FPGA version is its portability, it has to be easily modified and downloaded onto a device to estimate the percent of brittle fracture of the broken Charpy surface. The beauty of the DSP Builder programme is that it allows the model to be compiled to various types of optimised code for any Altera FPGA device. To provide a firm basis for scientific comparison to the new FPGA system, images already analysed via the PC based Java system were also used for testing and comparison purposes. The FPGA system converts the image into an 8 bit grayscale image and analyses it in a 5x5 sampling window. This produces texture features that can be used in a comparison system, similar to the Support Vector Machine (SVM) used in the original. The output is a signal that states the material being tested is brittle or not via an output of '1' for brittle and a '0' for ductile. A detailed pixel by pixel analysis of the various output images is then investigated to state the percentage difference between the PC and FPGA based systems.

  17. The development of a high speed solution for the evaluation of track structure Monte Carlo electron transport problems using field programmable gate arrays

    Science.gov (United States)

    Pasciak, Alexander Samuel

    There are two principal techniques for performing Monte Carlo electron transport computations. The first, and least common, is the full track-structure method. This method individually models all physical electron interactions including elastic scatter, electron impact ionization, radiative losses and excitations. However, because of the near infinite size of electron interaction cross-sections and highly anisotropic scattering behavior, this method requires an enormous amount of computation time. Alternatively, the Condensed History (CH) method for electron transport lumps the average effects of multiple energy loss and scattering events into one single pseudo-event, or step. Because of this approximation, the CH method can be orders of magnitude faster than the trackstructure method. While the CH method is reasonably accurate in many situations, it can be inaccurate for simulations involving microscopic site sizes such as those often found in radiation biology. For radiation biology and other microdosimetry applications, a computational device called a Field Programmable Gate Array (FPGA) is capable of executing track-structure Monte Carlo electron transport simulations as fast as, or faster than a standard computer performing transport via the CH method---and, it does so with the additional accuracy and level of detail provided by the track-structure method. In this dissertation, data from FPGA based track-structure electron transport computations are presented for five test cases, ranging in complexity from simple slab-style geometries to radiation biology applications involving electrons incident on endosteal bone surface cells. Even for the most complex test case presented, an FPGA is capable of evaluating track-structure electron transport problems more than 500 times faster than a standard computer can perform the same track-structure simulation, and with comparable accuracy.

  18. Functionalization and Characterization of Nanomaterial Gated Field-Effect Transistor-Based Biosensors and the Design of a Multi-Analyte Implantable Biosensing Platform

    Science.gov (United States)

    Croce, Robert A., Jr.

    Advances in semiconductor research and complementary-metal-oxide semiconductor fabrication allow for the design and implementation of miniaturized metabolic monitoring systems, as well as advanced biosensor design. The first part of this dissertation will focus on the design and fabrication of nanomaterial (single-walled carbon nanotube and quantum dot) gated field-effect transistors configured as protein sensors. These novel device structures have been functionalized with single-stranded DNA aptamers, and have shown sensor operation towards the protein Thrombin. Such advanced transistor-based sensing schemes present considerable advantages over traditional sensing methodologies in view of its miniaturization, low cost, and facile fabrication, paving the way for the ultimate realization of a multi-analyte lab-on-chip. The second part of this dissertation focuses on the design and fabrication of a needle-implantable glucose sensing platform which is based solely on photovoltaic powering and optical communication. By employing these powering and communication schemes, this design negates the need for bulky on-chip RF-based transmitters and batteries in an effort to attain extreme miniaturization required for needle-implantable/extractable applications. A complete single-sensor system coupled with a miniaturized amperometric glucose sensor has been demonstrated to exhibit reality of this technology. Furthermore, an optical selection scheme of multiple potentiostats for four different analytes (glucose, lactate, O 2 and CO2) as well as the optical transmission of sensor data has been designed for multi-analyte applications. The last part of this dissertation will focus on the development of a computational model for the amperometric glucose sensors employed in the aforementioned implantable platform. This model has been applied to single-layer single-enzyme systems, as well as multi-layer (single enzyme) systems utilizing glucose flux limiting layer-by-layer assembled

  19. Impact of strain on electronic and transport properties of 6 nm hydrogenated germanane nano-ribbon channel double gate field effect transistor

    Science.gov (United States)

    Meher Abhinav, E.; Sundararaj, Anuraj; Gopalakrishnan, Chandrasekaran; Kasmir Raja, S. V.; Chokhra, Saurabh

    2017-11-01

    In this work, chair like fully hydrogenated germanane (CGeH) nano-ribbon 6 nm short channel double gate field effect transistor (DG-FET) has been modeled and the impact of strain on the I–V characteristics of CGeH channel has been examined. The bond lengths, binding and formation energies of various hydrogenated geometries of buckled germanane channel were calculated using local density approximation (LDA) with Perdew–Zunger (PZ) and generalized gradient approximation (GGA) with Perdew Burke Ernzerhof (PBE) parameterization. From four various geometries, chair like structure is found to be more stable compared to boat like obtuse, stiruup structure and table like structure. The bandgap versus width, bandgap versus strain characteristics and I–V characteristics had been analyzed at room temperature using density functional theory (DFT). Using self consistent calculation it was observed that the electronic properties of nano-ribbon is independent of length and band structure, but dependent on edge type, strain [Uni-axial (ε xx ), bi-axial (ε xx   =  ε yy )] and width of the ribbon. The strain engineered hydrogenated germanane (GeH) showed wide direct bandgap (2.3 eV) which could help to build low noise electronic devices that operates at high frequencies. The observed bi-axial compression has high impact on the device transport characteristics with peak to valley ratio (PVR) of 2.14 and 380% increase in peak current compared to pristine CGeH device. The observed strain in CGeH DG-FET could facilitate in designing novel multiple-logic memory devices due to multiple negative differential resistance (NDR) regions.

  20. A Spaceborne Synthetic Aperture Radar Partial Fixed-Point Imaging System Using a Field- Programmable Gate Array−Application-Specific Integrated Circuit Hybrid Heterogeneous Parallel Acceleration Technique

    Directory of Open Access Journals (Sweden)

    Chen Yang

    2017-06-01

    Full Text Available With the development of satellite load technology and very large scale integrated (VLSI circuit technology, onboard real-time synthetic aperture radar (SAR imaging systems have become a solution for allowing rapid response to disasters. A key goal of the onboard SAR imaging system design is to achieve high real-time processing performance with severe size, weight, and power consumption constraints. In this paper, we analyse the computational burden of the commonly used chirp scaling (CS SAR imaging algorithm. To reduce the system hardware cost, we propose a partial fixed-point processing scheme. The fast Fourier transform (FFT, which is the most computation-sensitive operation in the CS algorithm, is processed with fixed-point, while other operations are processed with single precision floating-point. With the proposed fixed-point processing error propagation model, the fixed-point processing word length is determined. The fidelity and accuracy relative to conventional ground-based software processors is verified by evaluating both the point target imaging quality and the actual scene imaging quality. As a proof of concept, a field- programmable gate array−application-specific integrated circuit (FPGA-ASIC hybrid heterogeneous parallel accelerating architecture is designed and realized. The customized fixed-point FFT is implemented using the 130 nm complementary metal oxide semiconductor (CMOS technology as a co-processor of the Xilinx xc6vlx760t FPGA. A single processing board requires 12 s and consumes 21 W to focus a 50-km swath width, 5-m resolution stripmap SAR raw data with a granularity of 16,384 × 16,384.

  1. A Spaceborne Synthetic Aperture Radar Partial Fixed-Point Imaging System Using a Field- Programmable Gate Array-Application-Specific Integrated Circuit Hybrid Heterogeneous Parallel Acceleration Technique.

    Science.gov (United States)

    Yang, Chen; Li, Bingyi; Chen, Liang; Wei, Chunpeng; Xie, Yizhuang; Chen, He; Yu, Wenyue

    2017-06-24

    With the development of satellite load technology and very large scale integrated (VLSI) circuit technology, onboard real-time synthetic aperture radar (SAR) imaging systems have become a solution for allowing rapid response to disasters. A key goal of the onboard SAR imaging system design is to achieve high real-time processing performance with severe size, weight, and power consumption constraints. In this paper, we analyse the computational burden of the commonly used chirp scaling (CS) SAR imaging algorithm. To reduce the system hardware cost, we propose a partial fixed-point processing scheme. The fast Fourier transform (FFT), which is the most computation-sensitive operation in the CS algorithm, is processed with fixed-point, while other operations are processed with single precision floating-point. With the proposed fixed-point processing error propagation model, the fixed-point processing word length is determined. The fidelity and accuracy relative to conventional ground-based software processors is verified by evaluating both the point target imaging quality and the actual scene imaging quality. As a proof of concept, a field- programmable gate array-application-specific integrated circuit (FPGA-ASIC) hybrid heterogeneous parallel accelerating architecture is designed and realized. The customized fixed-point FFT is implemented using the 130 nm complementary metal oxide semiconductor (CMOS) technology as a co-processor of the Xilinx xc6vlx760t FPGA. A single processing board requires 12 s and consumes 21 W to focus a 50-km swath width, 5-m resolution stripmap SAR raw data with a granularity of 16,384 × 16,384.

  2. Multilayer ZnO/Pd/ZnO Structure as Sensing Membrane for Extended-Gate Field-Effect Transistor (EGFET) with High pH Sensitivity

    Science.gov (United States)

    Rasheed, Hiba S.; Ahmed, Naser M.; Matjafri, M. Z.; Al-Hardan, Naif H.; Almessiere, Munirah Abdullah; Sabah, Fayroz A.; Al-Hazeem, Nabeel Z.

    2017-10-01

    Metal oxide nanostructures have attracted considerable attention as pH-sensitive membranes because of their unique advantages. Specifically, the special properties of ZnO thin film, including high surface-to-volume ratio, nontoxicity, thermal stability, chemical stability, electrochemical activity, and high mechanical strength, have attracted massive interest. ZnO exhibits wide bandgap of 3.37 eV, good biocompatibility, high reactivity, robustness, and environmental stability. These unique properties explain why ZnO has the most applications among all nanostructured metal oxides based on its structure and properties. Moreover, ZnO has excellent electrical characteristics, enabling its use in accurate sensors with rapid response. ZnO nanostructures can be used in novel pH and biomedical sensing applications. However, ZnO thin film exhibits large sheet resistance and low conductivity. Increasing the conductivity or reducing the resistivity of ZnO sensing membranes is important to achieve low impedance. We propose herein a new design using a multilayer ZnO/Pd/ZnO structure as a pH-sensing membrane. Multiple layers were deposited by radio frequency (RF) sputtering for ZnO and direct current (DC) sputtering for Pd to achieve low sheet resistance. These multilayers with low sheet resistance of 15.8 Ω/sq were then successfully used to control the conductivity in extended-gate field-effect transistors (EGFETs). The resulting multilayered EGFET pH-sensor demonstrated improved sensing performance. The measured sensitivity of the pH sensor was 40 μA/pH and 52 mV/pH within the pH range from 2 to 12, rendering this structure suitable for use in various applications, including pH sensors and biosensors.

  3. High-performance ultraviolet photodetectors based on lattice-matched InAlN/AlGaN heterostructure field-effect transistors gated by transparent ITO films

    Science.gov (United States)

    Li, Lei; Hosomi, Daiki; Miyachi, Yuta; Hamada, Takeaki; Miyoshi, Makoto; Egawa, Takashi

    2017-09-01

    We demonstrate high-performance ultraviolet photodetectors (UV-PDs) based on lattice-matched (LM) InAlN/AlGaN heterostructure field-effect transistors (HFETs) gated by transparent ITO films. Low dark currents of 6.8 × 10-8 and 6.1 × 10-7 A/mm and high photocurrent gains over four and three orders of magnitude were obtained for the LM In0.12Al0.88N/Al0.21Ga0.79N and In0.10Al0.90N/Al0.34Ga0.66N HFETs, respectively. The negative threshold voltage shifts under illumination indicate that most of the photo-generated carriers are transported in the two-dimensional gas (2DEG) region around the InAlN/AlGaN interface. High peak responsivities of 2.2 × 104 and 5.4 × 104 A/W and large UV-to-visible rejection ratios greater than 104 and 103 were achieved for the LM In0.12Al0.88N/Al0.21Ga0.79N and In0.10Al0.90N/Al0.34Ga0.66N HFET-type UV-PDs, respectively. These improved performances with respect to other AlGaN UV-PDs around the same wavelength detection range may possibly be attributed to the greater contribution of the photogenerated electrons to the 2DEG, which results from the increase in the polarization sheet charge density at the InAlN/AlGaN interface. The LM InAlN/AlGaN heterostructures provide relatively promising candidates for realizing high-performance HFET-type UV-PDs.

  4. Optical Co-Incidence Gate | Srinivasulu | African Journal of Science ...

    African Journals Online (AJOL)

    The paper explains Optical co-incidence gate, realized using Unijunction transistors (UJT), Light emitting diodes (LED) and Photo-resistors (LDR), which works on 1.8Vdc instead of 3Vdc. The power dissipation of the designed gate is only 3 mW. This optical gate finds application in the field of Mechatronics, Instrumentation ...

  5. Application of optical logic gates | Srinivasulu | Zede Journal

    African Journals Online (AJOL)

    This paper proposes optical NOT. AND, and NOR gates using unijunction transistor (UJT), light emitting diode (LED), and light dependent resistor (LDR). Efforts are made to extend the development of these gates using LDR, LED, and UJT to work at 1.8V instead of 3V. These optical gates find their application in the field of ...

  6. Investigation of trap properties in high-k/metal gate p-type metal-oxide-semiconductor field-effect-transistors with aluminum ion implantation using random telegraph noise analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kao, Tsung-Hsien; Chang, Shoou-Jinn, E-mail: changsj@mail.ncku.edu.tw; Fang, Yean-Kuen; Huang, Po-Chin [Institute of Microelectronics and Department of Electrical Engineering, Advanced Optoelectronic Technology Center, Center for Micro/Nano Science and Technology, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan (China); Lai, Chien-Ming; Hsu, Chia-Wei; Chen, Yi-Wen; Cheng, Osbert [Central R and D Division, United Microelectronics Corporation, Ltd., Tainan Science-Based Industrial Park, Tainan 74145, Taiwan (China); Wu, Chung-Yi; Wu, San-Lein [Department of Electronic Engineering, Cheng Shiu University, 840 Chengcing Road, Niaosong, Kaohsiung 833, Taiwan (China)

    2014-08-11

    In this study, the impact of aluminum ion implantation (Al I/I) on random telegraph noise (RTN) in high-k/metal gate (HK/MG) p-type metal-oxide-semiconductor field-effect-transistors (pMOSFETs) was investigated. The trap parameters of HK/MG pMOSFETs with Al I/I, such as trap energy level, capture time and emission time, activation energies for capture and emission, and trap location in the gate dielectric, were determined. The configuration coordinate diagram was also established. It was observed that the implanted Al could fill defects and form a thin Al{sub 2}O{sub 3} layer and thus increase the tunneling barrier height for holes. It was also observed that the trap position in the Al I/I samples was lower due to the Al I/I-induced dipole at the HfO{sub 2}/SiO{sub 2} interface.

  7. Digital Microfluidic Logic Gates

    Science.gov (United States)

    Zhao, Yang; Xu, Tao; Chakrabarty, Krishnendu

    Microfluidic computing is an emerging application for microfluidics technology. We propose microfluidic logic gates based on digital microfluidics. Using the principle of electrowetting-on-dielectric, AND, OR, NOT and XOR gates are implemented through basic droplet-handling operations such as transporting, merging and splitting. The same input-output interpretation enables the cascading of gates to create nontrivial computing systems. We present a potential application for microfluidic logic gates by implementing microfluidic logic operations for on-chip HIV test.

  8. Design verification enhancement of field programmable gate array-based safety-critical I&C system of nuclear power plant

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Ibrahim [Department of Nuclear Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104 (Korea, Republic of); Jung, Jaecheon, E-mail: jcjung@kings.ac.kr [Department of Nuclear Power Plant Engineering, KEPCO International Nuclear Graduate School, 658-91 Haemaji-ro, Seosang-myeon, Ulju-gun, Ulsan 45014 (Korea, Republic of); Heo, Gyunyoung [Department of Nuclear Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin-si, Gyeonggi-do 17104 (Korea, Republic of)

    2017-06-15

    Highlights: • An enhanced, systematic and integrated design verification approach is proposed for V&V of FPGA-based I&C system of NPP. • RPS bistable fixed setpoint trip algorithm is designed, analyzed, verified and discussed using the proposed approaches. • The application of integrated verification approach simultaneously verified the entire design modules. • The applicability of the proposed V&V facilitated the design verification processes. - Abstract: Safety-critical instrumentation and control (I&C) system in nuclear power plant (NPP) implemented on programmable logic controllers (PLCs) plays a vital role in safe operation of the plant. The challenges such as fast obsolescence, the vulnerability to cyber-attack, and other related issues of software systems have currently led to the consideration of field programmable gate arrays (FPGAs) as an alternative to PLCs because of their advantages and hardware related benefits. However, safety analysis for FPGA-based I&C systems, and verification and validation (V&V) assessments still remain important issues to be resolved, which are now become a global research point of interests. In this work, we proposed a systematic design and verification strategies from start to ready-to-use in form of model-based approaches for FPGA-based reactor protection system (RPS) that can lead to the enhancement of the design verification and validation processes. The proposed methodology stages are requirement analysis, enhanced functional flow block diagram (EFFBD) models, finite state machine with data path (FSMD) models, hardware description language (HDL) code development, and design verifications. The design verification stage includes unit test – Very high speed integrated circuit Hardware Description Language (VHDL) test and modified condition decision coverage (MC/DC) test, module test – MATLAB/Simulink Co-simulation test, and integration test – FPGA hardware test beds. To prove the adequacy of the proposed

  9. Logic gates based on ion transistors.

    Science.gov (United States)

    Tybrandt, Klas; Forchheimer, Robert; Berggren, Magnus

    2012-05-29

    Precise control over processing, transport and delivery of ionic and molecular signals is of great importance in numerous fields of life sciences. Integrated circuits based on ion transistors would be one approach to route and dispense complex chemical signal patterns to achieve such control. To date several types of ion transistors have been reported; however, only individual devices have so far been presented and most of them are not functional at physiological salt concentrations. Here we report integrated chemical logic gates based on ion bipolar junction transistors. Inverters and NAND gates of both npn type and complementary type are demonstrated. We find that complementary ion gates have higher gain and lower power consumption, as compared with the single transistor-type gates, which imitates the advantages of complementary logics found in conventional electronics. Ion inverters and NAND gates lay the groundwork for further development of solid-state chemical delivery circuits.

  10. Stimuli-responsive smart gating membranes.

    Science.gov (United States)

    Liu, Zhuang; Wang, Wei; Xie, Rui; Ju, Xiao-Jie; Chu, Liang-Yin

    2016-02-07

    Membranes are playing paramount roles in the sustainable development of myriad fields such as energy, environmental and resource management, and human health. However, the unalterable pore size and surface properties of traditional porous membranes restrict their efficient applications. The performances of traditional membranes will be weakened upon unavoidable membrane fouling, and they cannot be applied to cases where self-regulated permeability and selectivity are required. Inspired by natural cell membranes with stimuli-responsive channels, artificial stimuli-responsive smart gating membranes are developed by chemically/physically incorporating stimuli-responsive materials as functional gates into traditional porous membranes, to provide advanced functions and enhanced performances for breaking the bottlenecks of traditional membrane technologies. Smart gating membranes, integrating the advantages of traditional porous membrane substrates and smart functional gates, can self-regulate their permeability and selectivity via the flexible adjustment of pore sizes and surface properties based on the "open/close" switch of the smart gates in response to environmental stimuli. This tutorial review summarizes the recent developments in stimuli-responsive smart gating membranes, including the design strategies and the fabrication strategies that are based on the introduction of the stimuli-responsive gates after or during membrane formation, and the positively and negatively responsive gating models of versatile stimuli-responsive smart gating membranes, as well as the advanced applications of smart gating membranes for regulating substance concentration in reactors, controlling the release rate of drugs, separating active molecules based on size or affinity, and the self-cleaning of membrane surfaces. With self-regulated membrane performances, smart gating membranes show great power for use in global sustainable development.

  11. Geodetic monitoring of suspended particles in rivers

    Science.gov (United States)

    Kamnik, Rok; Maksimova, Daria; Kovačič, Boštjan

    2017-10-01

    There is a trend in modern approach to the management of space of collecting the spatial data, in order to obtain useful information. In this paper a research of suspended particles in the river Drava and Mura will be introduced. The goal is to connect different fields of water management in countries where the rivers Drava and Mura flows in purpose of water management sustainability. The methods such as GNSS for mapping cross sections of the river, the use of ADCP (Acoustic Doppler Current Profiler) measurement system and water sampling to monitor sediment in the water will be presented.

  12. Gate Engineering in SOI LDMOS for Device Reliability

    Directory of Open Access Journals (Sweden)

    Aanand

    2016-01-01

    Full Text Available A linearly graded doping drift region with step gate structure, used for improvement of reduced surface field (RESURF SOI LDMOS transistor performance has been simulated with 0.35µm technology in this paper. The proposed device has one poly gate and double metal gate arranged in a stepped manner, from channel to drift region. The first gate uses n+ poly (near source where as other two gates of aluminium. The first gate with thin gate oxide has good control over the channel charge. The third gate with thick gate oxide at drift region reduce gate to drain capacitance. The arrangement of second and third gates in a stepped manner in drift region spreads the electric field uniformly. Using two dimensional device simulations, the proposed SOI LDMOS is compared with conventional structure and the extended metal structure. We demonstrate that the proposed device exhibits significant enhancement in linearity, breakdown voltage, on-resistance and HCI. Double metal gate reduces the impact ionization area which helps to improve the Hot Carrier Injection effect..

  13. Very low and broad threshold voltage fluctuation caused by ion implantation to silicon-on-insulator triple-gate fin-type field effect transistor using three-dimensional process and device simulations

    Science.gov (United States)

    Tsutsumi, Toshiyuki

    2017-06-01

    The threshold voltage (V th) fluctuation induced by the ion implantation to the source and drain extensions (SDE) of a silicon-on-insulator (SOI) triple-gate (tri-gate) fin-type field-effect transistor (FinFET) was analyzed for the first time with the use of realistic positional information of discretely doped ions by both three-dimensional (3D) process and device simulations. Interestingly, it was found that the V th fluctuation induced by SDE ion implantation has a very low and broad distribution on the low-V th side even in the case of a robust device structure such as SOI tri-gate FinFET. Furthermore, for the first time, it was quantitatively demonstrated using a proposed cluster percolation model that the origin of the very low and broad V th fluctuation is the conductive percolation among unintentionally doped ions in the channel region of the device. These results would contribute to the realization of robust transistors.

  14. Memory and negative-resistance effects in a strained metal-gate high-k n-type field-effect-transistor from 375 K down to 77 K

    Science.gov (United States)

    Gutiérrez-D, E. A.; Vega-G, V. H.; García-R, P. J.; Huerta-G, O. V.

    2016-12-01

    We introduce an experimental alternative way of looking into the charging and discharging mechanism inside a high-k stacked oxide of a metal-gate strained n-type Field-Effect-Transistor (nFET). This alternative way reproduces a memory and negative resistance effect by biasing the nFET device in a non-conventional way. This is achieved by forward-biasing the drain-bulk junction and by setting the gate electrode in a high-impedance mode. The produced negative resistance effect (NRE) has a controllable peak-to-valley current ratio (PVCR) that goes from about 3.0 up to a value of 5.5 at room temperature. The PVCR increases up to 8.35 at T = 225 K and reduces to 2.84 at T = 375 K in a linear trend. The memory effect is observed when the drain-bulk junction voltage is swept from low to high values and back from high to low values. From low to high forward drain-bulk bias the NRE shows up and vanishes when coming back from high to low forward drain-bulk bias. The NRE and memory effects are attributed to a coupled-gate oxide charging/discharging mechanism with an induced bipolar transistor action in the channel of the FET.

  15. Crystalline ZrTiO{sub 4} gated p-metal–oxide–semiconductor field effect transistors with sub-nm equivalent oxide thickness featuring good electrical characteristics and reliability

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chao-Yi; Hsieh, Ching-Heng; Lee, Ching-Wei; Wu, Yung-Hsien [Department of Engineering and System Science, National Tsing Hua University, 300 Hsinchu, Taiwan (China)

    2015-02-02

    ZrTiO{sub 4} crystallized in orthorhombic (o-) phase was stacked with an amorphous Yb{sub 2}O{sub 3} interfacial layer as the gate dielectric for Si-based p-MOSFETs. With thermal annealing after gate electrode, the gate stack with equivalent oxide thickness (EOT) of 0.82 nm achieves high dielectric quality by showing a low interface trap density (D{sub it}) of 2.75 × 10{sup 11 }cm{sup −2}eV{sup −1} near the midgap and low oxide traps. Crystallization of ZrTiO{sub 4} and post metal annealing are also proven to introduce very limited amount of metal induced gap states or interfacial dipole. The p-MOSFETs exhibit good sub-threshold swing of 75 mV/dec which is ascribed to the low D{sub it} value and small EOT. Owing to the Y{sub 2}O{sub 3} interfacial layer and smooth interface with Si substrate that, respectively, suppress phonon and surface roughness scattering, the p-MOSFETs also display high hole mobility of 49 cm{sup 2}/V-s at 1 MV/cm. In addition, I{sub on}/I{sub off} ratio larger than 10{sup 6} is also observed. From the reliability evaluation by negative bias temperature instability test, after stressing with an electric field of −10 MV/cm at 85 °C for 1000 s, satisfactory threshold voltage shift of 12 mV and sub-threshold swing degradation of 3% were obtained. With these promising characteristics, the Yb{sub 2}O{sub 3}/o-ZrTiO{sub 4} gate stack holds the great potential for next-generation electronics.

  16. Suspended sediment apportionment in a South-Korean mountain catchment

    Science.gov (United States)

    Birkholz, Axel; Meusburger, Katrin; Park, Ji-Hyung; Alewell, Christine

    2016-04-01

    Due to the rapid agricultural expansion and intensification during the last decades in South-Korea, large areas of hill slope forests were transformed to paddies and vegetable fields. The intensive agriculture and the easily erodible soils in our catchment are a major reason for the increased erosion causing suspended sediments to infiltrate into the close drinking water reservoir. The drinking water reservoir Lake Soyang provides water supply for over ten million people in Seoul. Landscape managers need to know the exact origin of these sediments before they can create landscape amelioration schemes. We applied a compound-specific stable isotope (CSSI) approach (Alewell et al., 2015) to apportion the sources of the suspended sediments between forest and agricultural soil contribution to the suspended sediments in a different catchment and applied the same approach to identify and quantify the different sources of the suspended sediments in the river(s) contributing to Lake Soyang. We sampled eight soil sites within the catchment considering the different landuse types forest, rice paddies, maize and vegetables. Suspended sediments were sampled at three outlets of the different sub-catchments. Soils and suspended sediments are analysed for bulk carbon and nitrogen isotopes, compound-specific carbon isotopes of plant-wax derived long-chain fatty acids and long-chain n-alkanes. Fatty acid and alkane isotopes are then used in mixing calculations and the mixing model software IsoSource to find out the contribution of the different source soils to the suspended sediments. We present first data of the source soils and the suspended sediments. C. Alewell, A. Birkholz, K. Meusburger, Y. Schindler-Wildhaber, L. Mabit, 2015. Sediment source attribution from multiple land use systems with CSIA. Biogeosciences Discuss. 12: 14245-14269.

  17. Current Source Logic Gate

    Science.gov (United States)

    Krasowski, Michael J. (Inventor); Prokop, Norman F. (Inventor)

    2017-01-01

    A current source logic gate with depletion mode field effect transistor ("FET") transistors and resistors may include a current source, a current steering switch input stage, and a resistor divider level shifting output stage. The current source may include a transistor and a current source resistor. The current steering switch input stage may include a transistor to steer current to set an output stage bias point depending on an input logic signal state. The resistor divider level shifting output stage may include a first resistor and a second resistor to set the output stage point and produce valid output logic signal states. The transistor of the current steering switch input stage may function as a switch to provide at least two operating points.

  18. MR-guided percutaneous biopsy of solitary pulmonary lesions using a 1.0-T open high-field MRI scanner with respiratory gating

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ming; Huang, Jie; Xu, Yujun; He, Xiangmeng; Lue, Yubo; Liu, Qiang; Li, Chengli [Department of Interventional MRI, Shandong Medical Imaging Research Institute affiliated to Shandong University, Shandong Key Laboratory of Advanced Medical Imaging Technologies and Applications, Jinan, Shandong (China); Li, Lei [Qingdao Central Hospital, Department of Interventional Radiology, Qingdao, Shandong (China); Blanco Sequeiros, Roberto [Turku University Hospital, The South Western Finland Imaging Centre, Turku (Finland)

    2017-04-15

    To prospectively evaluate the feasibility, safety and accuracy of MR-guided percutaneous biopsy of solitary pulmonary lesions using a 1.0-T open MR scanner with respiratory gating. Sixty-five patients with 65 solitary pulmonary lesions underwent MR-guided percutaneous coaxial cutting needle biopsy using a 1.0-T open MR scanner with respiratory gating. Lesions were divided into two groups according to maximum lesion diameters: ≤2.0 cm (n = 31) and >2.0 cm (n = 34). The final diagnosis was established in surgery and subsequent histology. Diagnostic accuracy, sensitivity and specificity were compared between the groups using Fisher's exact test. Accuracy, sensitivity and specificity of MRI-guided percutaneous pulmonary biopsy in diagnosing malignancy were 96.9 %, 96.4 % and 100 %, respectively. Accuracy, sensitivity and specificity were 96.8 %, 96.3 % and 100 % for lesions 2.0 cm or smaller and 97.1 %, 96.4 % and 100 %, respectively, for lesions larger than 2.0 cm. There was no significant difference between the two groups (P > 0.05). Biopsy-induced complications encountered were pneumothorax in 12.3 % (8/65) and haemoptysis in 4.6 % (3/65). There were no serious complications. MRI-guided percutaneous biopsy using a 1.0-T open MR scanner with respiratory gating is an accurate and safe diagnostic technique in evaluation of pulmonary lesions. (orig.)

  19. Physical understanding of different drain-induced-barrier-lowering variations in high-k/metal gate n-channel metal-oxide-semiconductor-field-effect-transistors induced by charge trapping under normal and reverse channel hot carrier stresses

    Science.gov (United States)

    Luo, Weichun; Yang, Hong; Wang, Wenwu; Zhao, Lichuan; Xu, Hao; Ren, Shangqing; Tang, Bo; Tang, Zhaoyun; Xu, Yefeng; Xu, Jing; Yan, Jiang; Zhao, Chao; Chen, Dapeng; Ye, Tianchun

    2013-10-01

    In this paper, the drain induced barrier lowering (DIBL) variations in High-k/Metal gate n-channel metal-oxide-semiconductor field effect transistor under the normal and reverse channel hot carrier (CHC) stress are studied. It is found that DIBL decreases under normal CHC stress mode while increases under reverse CHC mode. The different DIBL variation under normal and reverse CHC stresses is proposed to be attributed to stress-induced charge trapping by cold carriers from the channel rather than hot carriers from the pinch off region, which can be explained by energy band bending theory.

  20. Suspended animation for delayed resuscitation.

    Science.gov (United States)

    Safar, Peter J; Tisherman, Samuel A

    2002-04-01

    'Suspended animation for delayed resuscitation' is a new concept for attempting resuscitation from cardiac arrest of patients who currently (totally or temporarily) cannot be resuscitated, such as traumatic exsanguination cardiac arrest. Suspended animation means preservation of the viability of brain and organism during cardiac arrest, until restoration of stable spontaneous circulation or prolonged artificial circulation is possible. Suspended animation for exsanguination cardiac arrest of trauma victims would have to be induced within the critical first 5 min after the start of cardiac arrest no-flow, to buy time for transport and resuscitative surgery (hemostasis) performed during no-flow. Cardiac arrest is then reversed with all-out resuscitation, usually requiring cardiopulmonary bypass. Suspended animation has been explored and documented as effective in dogs in terms of long-term survival without brain damage after very prolonged cardiac arrest. In the 1990s, the Pittsburgh group achieved survival without brain damage in dogs after cardiac arrest of up to 90 min no-flow at brain (tympanic) temperature of 10 degrees C, with functionally and histologically normal brains. These studies used emergency cardiopulmonary bypass with heat exchanger or a single hypothermic saline flush into the aorta, which proved superior to pharmacologic strategies. For the large number of normovolemic sudden cardiac death victims, which currently cannot be resuscitated, more research in large animals is needed.

  1. G4-FETs as Universal and Programmable Logic Gates

    Science.gov (United States)

    Johnson, Travis; Fijany, Amir; Mojarradi, Mohammad; Vatan, Farrokh; Toomarian, Nikzad; Kolawa, Elizabeth; Cristoloveanu, Sorin; Blalock, Benjamin

    2007-01-01

    An analysis of a patented generic silicon- on-insulator (SOI) electronic device called a G4-FET has revealed that the device could be designed to function as a universal and programmable logic gate. The universality and programmability could be exploited to design logic circuits containing fewer discrete components than are required for conventional transistor-based circuits performing the same logic functions. A G4-FET is a combination of a junction field-effect transistor (JFET) and a metal oxide/semiconductor field-effect transistor (MOSFET) superimposed in a single silicon island and can therefore be regarded as two transistors sharing the same body. A G4-FET can also be regarded as a single transistor having four gates: two side junction-based gates, a top MOS gate, and a back gate activated by biasing of the SOI substrate. Each of these gates can be used to control the conduction characteristics of the transistor; this possibility creates new options for designing analog, radio-frequency, mixed-signal, and digital circuitry. With proper choice of the specific dimensions for the gates, channels, and ancillary features of the generic G4-FET, the device could be made to function as a three-input, one-output logic gate. As illustrated by the truth table in the top part of the figure, the behavior of this logic gate would be the inverse (the NOT) of that of a majority gate. In other words, the device would function as a NOT-majority gate. By simply adding an inverter, one could obtain a majority gate. In contrast, to construct a majority gate in conventional complementary metal oxide/semiconductor (CMOS) circuitry, one would need four three-input AND gates and a four-input OR gate, altogether containing 32 transistors.

  2. Remote Sensing Studies of Suspended Sediment Concentration Variation in Barito Delta

    Science.gov (United States)

    Arisanty, Deasy; Nur Saputra, Aswin

    2017-12-01

    The dynamic of suspended sediment concentration in Barito Delta depend on the process in upstream. Agriculture, mining, and illegal logging in Barito River upstream has an effect for suspended sediment concentration in Barito Delta. The objective of research is to estimate the variation of suspended sediment concentration in Barito Delta. The data of research consist of Landsat 7 in year 2011 and measurement result data of suspended sediment concentration both in wet season and dry season in year 2011. Data analysis is regression analysis to estimates the variation of suspended sediment concentration in Barito Delta. The method of research compares three types of spectral transformation for suspended sediment that is Normalized Suspended Material Index (NSMI), Normalized Differences Suspended Sediment Index (NDSSI), and band ratio (green/blue). The result of the transformation is compared with the value of the field measurement. Based on the result of the comparison can be known the suitable type of transformation for the suspended sediment estimation in Barito Delta. The result of research explains that NSMI has the highest value to estimate the variation of suspended sediment concentration in Barito Delta.

  3. 7 CFR 1206.21 - Suspend.

    Science.gov (United States)

    2010-01-01

    ... part thereof during a particular period of time specified in the rule. ... AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.21 Suspend. Suspend means to...

  4. Optical Logic Gates

    Science.gov (United States)

    Du Fresne, E. R.; Dowler, W. L.

    1985-01-01

    Logic gates for light signals constructed from combinations of prisms, polarizing plates, and quarterwave plates. Optical logic gate performs elementary logic operation on light signals received along two optical fibers. Whether gate performs OR function or exclusive-OR function depends on orientation of analyzer. Nonbinary truth tables also obtained by rotating polarizer or analyzer to other positions or inserting other quarter-wave plates.

  5. Method for separating biological cells. [suspended in aqueous polymer systems

    Science.gov (United States)

    Brooks, D. E. (Inventor)

    1980-01-01

    A method for separating biological cells by suspending a mixed cell population in a two-phase polymer system is described. The polymer system consists of droplet phases with different surface potentials for which the cell populations exhibit different affinities. The system is subjected to an electrostatic field of sufficient intensity to cause migration of the droplets with an attendant separation of cells.

  6. An All-Solid-State pH Sensor Employing Fluorine-Terminated Polycrystalline Boron-Doped Diamond as a pH-Insensitive Solution-Gate Field-Effect Transistor.

    Science.gov (United States)

    Shintani, Yukihiro; Kobayashi, Mikinori; Kawarada, Hiroshi

    2017-05-05

    A fluorine-terminated polycrystalline boron-doped diamond surface is successfully employed as a pH-insensitive SGFET (solution-gate field-effect transistor) for an all-solid-state pH sensor. The fluorinated polycrystalline boron-doped diamond (BDD) channel possesses a pH-insensitivity of less than 3mV/pH compared with a pH-sensitive oxygenated channel. With differential FET (field-effect transistor) sensing, a sensitivity of 27 mv/pH was obtained in the pH range of 2-10; therefore, it demonstrated excellent performance for an all-solid-state pH sensor with a pH-sensitive oxygen-terminated polycrystalline BDD SGFET and a platinum quasi-reference electrode, respectively.

  7. Trap state passivation improved hot-carrier instability by zirconium-doping in hafnium oxide in a nanoscale n-metal-oxide semiconductor-field effect transistors with high-k/metal gate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hsi-Wen; Tsai, Jyun-Yu; Liu, Kuan-Ju; Lu, Ying-Hsin [Department of Physics, National Sun Yat-sen University, 70 Lien-hai Road, Kaohsiung 80424, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang3708@gmail.com [Department of Physics, National Sun Yat-sen University, 70 Lien-hai Road, Kaohsiung 80424, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Tainan 701, Taiwan (China); Chen, Ching-En; Tseng, Tseung-Yuen [Department of Electronics Engineering, National Chiao Tung University, Hsinchu 300, Taiwan (China); Lin, Chien-Yu [Department of Photonics, National Sun Yat-Sen University, 70 Lien-hai Road, Kaohsiung 80424, Taiwan (China); Cheng, Osbert; Huang, Cheng-Tung; Ye, Yi-Han [Device Department, United Microelectronics Corporation, Tainan Science Park, Tainan 701, Taiwan (China)

    2016-04-25

    This work investigates the effect on hot carrier degradation (HCD) of doping zirconium into the hafnium oxide high-k layer in the nanoscale high-k/metal gate n-channel metal-oxide-semiconductor field-effect-transistors. Previous n-metal-oxide semiconductor-field effect transistor studies demonstrated that zirconium-doped hafnium oxide reduces charge trapping and improves positive bias temperature instability. In this work, a clear reduction in HCD is observed with zirconium-doped hafnium oxide because channel hot electron (CHE) trapping in pre-existing high-k bulk defects is the main degradation mechanism. However, this reduced HCD became ineffective at ultra-low temperature, since CHE traps in the deeper bulk defects at ultra-low temperature, while zirconium-doping only passivates shallow bulk defects.

  8. Scanning gate microscopy of ultra clean carbon nanotube quantum dots

    OpenAIRE

    Xue, Jiamin; Dhall, Rohan; Cronin, Stephen B.; LeRoy, Brian J.

    2015-01-01

    We perform scanning gate microscopy on individual suspended carbon nanotube quantum dots. The size and position of the quantum dots can be visually identified from the concentric high conductance rings. For the ultra clean devices used in this study, two new effects are clearly identified. Electrostatic screening creates non-overlapping multiple sets of Coulomb rings from a single quantum dot. In double quantum dots, by changing the tip voltage, the interactions between the quantum dots can b...

  9. Hydrodynamic and suspended sediment transport controls on river mouth morphology

    Science.gov (United States)

    Falcini, F.; Piliouras, A.; Garra, R.; Guerin, A.; Jerolmack, D. J.; Rowland, J.; Paola, C.

    2014-01-01

    mouths building into standing bodies of water have strikingly varied growth habits. This presents a compelling pattern formation problem that is also of great practical relevance for subsurface prediction and managing coastal wetlands. Here we present a generalized 2.5-dimensional potential vorticity (PV) theory that explains sedimentation patterns of a sediment-laden stationary jet by coupling an understanding of vorticity with suspended sediment concentration fields. We explore the physical meaning of this new sediment-PV definition, and its impact on outflow depositional patterns, by analyzing data from a shallow wall-bounded plane jet experiment and by discussing new theoretical insights. A key result is that lateral advection and diffusion of suspended sediment are directly proportional to jet vorticity, a feature that reveals the mechanistic process that forms elongated channels by focused levee deposition. The new PV theory constitutes a more generalized mathematical framework that expands the Rouse theory for the equilibrium of suspended sediment.

  10. Synthesizing Biomolecule-based Boolean Logic Gates

    Science.gov (United States)

    Miyamoto, Takafumi; Razavi, Shiva; DeRose, Robert; Inoue, Takanari

    2012-01-01

    One fascinating recent avenue of study in the field of synthetic biology is the creation of biomolecule-based computers. The main components of a computing device consist of an arithmetic logic unit, the control unit, memory, and the input and output devices. Boolean logic gates are at the core of the operational machinery of these parts, hence to make biocomputers a reality, biomolecular logic gates become a necessity. Indeed, with the advent of more sophisticated biological tools, both nucleic acid- and protein-based logic systems have been generated. These devices function in the context of either test tubes or living cells and yield highly specific outputs given a set of inputs. In this review, we discuss various types of biomolecular logic gates that have been synthesized, with particular emphasis on recent developments that promise increased complexity of logic gate circuitry, improved computational speed, and potential clinical applications. PMID:23526588

  11. Gates Speaks to Librarians.

    Science.gov (United States)

    St. Lifer, Evan

    1997-01-01

    In an interview, Microsoft CEO Bill Gates answers questions about the Gates Library Foundation; Libraries Online; tax-support for libraries; comparisons to Andrew Carnegie; charges of "buying" the library market; Internet filters, policies, and government censorship; the future of the World Wide Web and the role of librarians in its…

  12. Compact drain-current model for undoped cylindrical surrounding-gate metal-oxide-semiconductor field effect transistors including short channel effects

    Science.gov (United States)

    Smaani, Billel; Latreche, Saida; Iñiguez, Benjamín

    2013-12-01

    In this paper, we present a compact model for undoped short-channel cylindrical surrounding-gate MOSFETs. The drain-current model is expressed as a function of the mobile charge density, which is calculated using the analytical expressions of the surface potential and the difference between surface and center potentials model. The short-channel effects are well incorporated in the drain-current model, such as the drain-induced barrier lowering, the charge sharing effect (VT Roll-off), the subthreshold slope degradation, and the channel length modulation. A comparison of the model results with 3D numerical simulations using Silvaco Atlas-TCAD presents a good agreement from subthreshold to strong inversion regime and for different bias voltages.

  13. Sub-harmonic gap structure and Magneto-transport in suspended graphene -Superconductor ballistic junctions

    Science.gov (United States)

    Kumaravadivel, Piranavan; Du, Xu

    2015-03-01

    Inducing superconductivity in graphene via the proximity effect enables to study the rich transport of the massless Dirac fermions at the Superconductor(S) - Graphene (G) interface. Some of the predictions are pseudo diffusive transport in Ballistic SGS junctions at low carrier densities and the unique specular and retro Andreev reflections in graphene. One of the challenges in observing these experimentally is to fabricate highly transparent ballistic SGS junctions that can be probed at low carrier densities near the Dirac point. In this talk we will present our recent results on suspended graphene- Niobium Josephson weak links. Our devices exhibit a mobility of ~ 350000 cm2V-1s-1 with a carrier density as low as 109 cm-2. Below the Superconducting transition temperature (Tc) ~ 9K, the devices show supercurrent and sub-harmonic gap structure due to Multiple Andreev reflections. In the vicinity of the Dirac point, the sub-harmonic gap structure becomes more pronounced, which as predicated, is indicative of pseudo-diffusive transport. With a fine scanning of gate voltage close to Dirac point we see emergence of some unusual sub- gap structures. We also report on our study of these samples below the upper critical field of Nb (~ 3.5T), where superconducting proximity effect coexists with Quantum Hall effect.

  14. A two-dimensional model for the potential distribution and threshold voltage of short-channel double-gate metal-oxide-semiconductor field-effect transistors with a vertical Gaussian-like doping profile

    Science.gov (United States)

    Dubey, Sarvesh; Tiwari, Pramod Kumar; Jit, S.

    2010-08-01

    A two-dimensional (2D) model for the threshold voltage of the short-channel double-gate (DG) metal-oxide-semiconductor field-effect transistors (MOSFETs) with a vertical Gaussian-like doping profile is proposed in this paper. The evanescent mode analysis has been used to solve the 2D Poisson's equation to obtain the channel potential function of the device. The minimum surface potential has been used to model the threshold voltage of the DG MOSFETs. Threshold voltage variations against channel length for different device parameters have been demonstrated. The validity of the proposed model is shown by comparing the results with the numerical simulation data obtained by using the commercially available ATLAS™, a 2D device simulator from SILVACO.

  15. Rippling instabilities in suspended nanoribbons

    Science.gov (United States)

    Wang, Hailong; Upmanyu, Moneesh

    2012-11-01

    Morphology mediates the interplay between the structure and electronic transport in atomically thin nanoribbons such as graphene as the relaxation of edge stresses occurs preferentially via out-of-plane deflections. In the case of end-supported suspended nanoribbons that we study here, past experiments and computations have identified a range of equilibrium morphologies, in particular, for graphene flakes, yet a unified understanding of their relative stability remains elusive. Here, we employ atomic-scale simulations and a composite framework based on isotropic elastic plate theory to chart out the morphological stability space of suspended nanoribbons with respect to intrinsic (ribbon elasticity) and engineered (ribbon geometry) parameters, and the combination of edge and body actuation. The computations highlight a rich morphological shape space that can be naturally classified into two competing shapes, bendinglike and twistlike, depending on the distribution of ripples across the interacting edges. The linearized elastic framework yields exact solutions for these rippled shapes. For compressive edge stresses, the body strain emerges as a key variable that controls their relative stability and in extreme cases stabilizes coexisting transverse ripples. Tensile edge stresses lead to dimples within the ribbon core that decay into the edges, a feature of obvious significance for stretchable nanoelectronics. The interplay between geometry and mechanics that we report should serve as a key input for quantifying the transport along these ribbons.

  16. Investigation of the stability of melt flow in gating systems

    DEFF Research Database (Denmark)

    Tiedje, Niels Skat; Larsen, Per

    2011-01-01

    description of free liquid surfaces proved to be incorrect in the numerical model. Modelled pressure fields served to explain how specific parts of the gating systems cause instability and are a good tool to describe the quality of a gating system. The results shows clearly that sharp changes in the geometry...

  17. Analyzing Single-Event Gate Ruptures In Power MOSFET's

    Science.gov (United States)

    Zoutendyk, John A.

    1993-01-01

    Susceptibilities of power metal-oxide/semiconductor field-effect transistors (MOSFET's) to single-event gate ruptures analyzed by exposing devices to beams of energetic bromine ions while applying appropriate bias voltages to source, gate, and drain terminals and measuring current flowing into or out of each terminal.

  18. Characteristics Of Ferroelectric Logic Gates Using a Spice-Based Model

    Science.gov (United States)

    MacLeod, Todd C.; Phillips, Thomas A.; Ho, Fat D.

    2005-01-01

    A SPICE-based model of an n-channel ferroelectric field effect transistor has been developed based on both theoretical and empirical data. This model was used to generate the I-V characteristic of several logic gates. The use of ferroelectric field effect transistors in memory circuits is being developed by several organizations. The use of FFETs in other circuits, both analog and digital needs to be better understood. The ability of FFETs to have different characteristics depending on the initial polarization can be used to create logic gates. These gates can have properties not available to standard CMOS logic gates, such as memory, reconfigurability and memory. This paper investigates basic properties of FFET logic gates. It models FFET inverter, NAND gate and multi-input NAND gate. The I-V characteristics of the gates are presented as well as transfer characteristics and timing. The model used is a SPICE-based model developed from empirical data from actual Ferroelectric transistors. It simulates all major characteristics of the ferroelectric transistor, including polarization, hysteresis and decay. Contrasts are made of the differences between FFET logic gates and CMOS logic gates. FFET parameters are varied to show the effect on the overall gate. A recodigurable gate is investigated which is not possible with CMOS circuits. The paper concludes that FFETs can be used in logic gates and have several advantages over standard CMOS gates.

  19. Thermal instability of Walters B' viscoelastic fluid permeated with suspended particles in hydromagnetics in porous medium

    Directory of Open Access Journals (Sweden)

    Kumar Pardeep

    2004-01-01

    Full Text Available The effect of suspended particles on the thermal instability of Walters B' viscoelastic fluid in hydromantic in porous medium is considered. For stationary convection, Walters B' viscoelastic fluid behaves like a Newtonian fluid. The medium permeability and suspended particles has ten the onset of convection whereas the magnetic field postpones the onset of convection, for the case of stationary convection. The magnetic field and viscoelasticity intro duce oscillatory modes in the system which was non-existent in their absence.

  20. Reversible gates and circuits descriptions

    Science.gov (United States)

    Gracki, Krzystof

    2017-08-01

    This paper presents basic methods of reversible circuit description. To design reversible circuit a set of gates has to be chosen. Most popular libraries are composed of three types of gates so called CNT gates (Control, NOT and Toffoli). The gate indexing method presented in this paper is based on the CNT gates set. It introduces a uniform indexing of the gates used during synthesis process of reversible circuits. The paper is organized as follows. Section 1 recalls basic concepts of reversible logic. In Section 2 and 3 a graphical representation of the reversible gates and circuits is described. Section 4 describes proposed uniform NCT gates indexing. The presented gate indexing method provides gate numbering scheme independent of lines number of the designed circuit. The solution for a circuit consisting of smaller number of lines is a subset of solution for a larger circuit.

  1. Effects of 15 Hz square wave magnetic fields on the voltage-gated sodium and potassium channels in prefrontal cortex pyramidal neurons.

    Science.gov (United States)

    Zheng, Yu; Dou, Jun-Rong; Gao, Yang; Dong, Lei; Li, Gang

    2017-04-01

    Although magnetic fields have significant effects on neurons, little is known about the mechanisms behind their effects. The present study aimed to measure the effects of magnetic fields on ion channels in cortical pyramidal neurons. Cortical pyramidal neurons of Kunming mice were isolated and then subjected to 15 Hz, 1 mT square wave (duty ratio 50%) magnetic fields stimulation. Sodium currents (INa), transient potassium currents (IA) and delayed rectifier potassium currents (IK) were recorded by whole-cell patch clamp method. We found that magnetic field exposure depressed channel current densities, and altered the activation kinetics of sodium and potassium channels. The inactivation properties of INa and IA were also altered. Magnetic field exposure alters ion channel function in neurons. It is likely that the structures of sodium and potassium channels were influenced by the applied field. Sialic acid, which is an important component of the channels, could be the molecule responsible for the reported results.

  2. Advanced insulated gate bipolar transistor gate drive

    Science.gov (United States)

    Short, James Evans [Monongahela, PA; West, Shawn Michael [West Mifflin, PA; Fabean, Robert J [Donora, PA

    2009-08-04

    A gate drive for an insulated gate bipolar transistor (IGBT) includes a control and protection module coupled to a collector terminal of the IGBT, an optical communications module coupled to the control and protection module, a power supply module coupled to the control and protection module and an output power stage module with inputs coupled to the power supply module and the control and protection module, and outputs coupled to a gate terminal and an emitter terminal of the IGBT. The optical communications module is configured to send control signals to the control and protection module. The power supply module is configured to distribute inputted power to the control and protection module. The control and protection module outputs on/off, soft turn-off and/or soft turn-on signals to the output power stage module, which, in turn, supplies a current based on the signal(s) from the control and protection module for charging or discharging an input capacitance of the IGBT.

  3. Stability of Quantum Loops and Exchange Operations in the Construction of Quantum Computation Gates

    Science.gov (United States)

    Bermúdez, D.; Delgado, F.

    2017-05-01

    Quantum information and quantum computation is a rapidly emergent field where quantum systems and their applications play a central role. In the gate version of quantum computation, the construction of universal quantum gates to manipulate quantum information is currently an intensive arena for quantum engineering. Specific properties of systems should be able to reproduce such idealized gates imitating the classically inspired computational gates. Recently, for magnetic systems driven by the bipartite Heisenberg-Ising model a universal set of gates has been realized, an alternative easy design for the Boykin set but using the Bell states as grammar. Exact control can be then used to construct specific prescriptions to achieve those gates. Physical parameters impose a challenge in the gate control. This work analyzes, based on the worst case quantum fidelity, the associated instability for the proposed set of gates. An strong performance is found in those gates for the most of quantum states involved.

  4. Experimental Study of Effective Carrier Mobility of Multi-Fin-Type Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistors with (111) Channel Surface Fabricated by Orientation-Dependent Wet Etching

    Science.gov (United States)

    Liu, Yongxun; Sugimata, Etsuro; Ishii, Kenichi; Masahara, Meishoku; Endo, Kazuhiko; Matsukawa, Takashi; Yamauchi, Hiromi; O'uchi, Shinichi; Suzuki, Eiichi

    2006-04-01

    We present an experimental study of effective carrier mobility ( μ eff) of multi-fin-type double-gate metal-oxide-semiconductor field-effect transistors (FinFETs) with a (111) channel surface fabricated by orientation-dependent wet etching. The peak values of the obtained μ eff of electrons and holes are approximately 300 and 160 cm2/(V s), respectively, which are close to those in (111) bulk metal-oxide-semiconductor field-effect transistors (MOSFETs). Moreover, the effective electric field (Eeff) dependence of the μ eff of electrons and holes shows a good agreement with the mobility universal curves of (111) bulk MOSFETs. These results indicate that the quality and channel surface roughness of Si-fins by orientation-dependent wet etching are excellent. The obtained results of μ eff are very useful for the modeling and design of FinFET-complementary metal-oxide-semiconductor (CMOS) circuits and the developed wet etching technique is very attractive in the fabrication of ultrathin and high-quality Si-fin channels.

  5. Method for voltage-gated protein fractionation

    Science.gov (United States)

    Hatch, Anson [Tracy, CA; Singh, Anup K [Danville, CA

    2012-04-24

    We report unique findings on the voltage dependence of protein exclusion from the pores of nanoporous polymer exclusion membranes. The pores are small enough that proteins are excluded from passage with low applied electric fields, but increasing the field enables proteins to pass through. The requisite field necessary for a change in exclusion is protein-specific with a correlation to protein size. The field-dependence of exclusion is important to consider for preconcentration applications. The ability to selectively gate proteins at exclusion membranes is also a promising means for manipulating and characterizing proteins. We show that field-gated exclusion can be used to selectively remove proteins from a mixture, or to selectively trap protein at one exclusion membrane in a series.

  6. A System For High Flexibility Entangling Gates With Trapped Ions

    Science.gov (United States)

    Milne, Alistair; Edmunds, Claire; Mavadia, Sandeep; Green, Todd; Biercuk, Michael

    Trapped ion qubits may be entangled via coupling to shared modes of motion using spin-dependent forces generated by optical fields. Residual qubit-motional coupling at the conclusion of the entangling operation is the dominant source of infidelity in this type of gate. For synchronously entangling increasing numbers of ions, longer gate times are required to minimise this residual coupling. We present a scheme that enables the state of each qubit to be simultaneously decoupled from all motional modes in an arbitrarily chosen gate time, increasing the gate fidelity and scalability. This is achieved by implementing discrete phase shifts in the optical field moderating the entangling operation. We describe an experimental system based on trapped ytterbium ions and demonstrate this scheme for two-qubit entangling gates on ytterbium ion pairs.

  7. 23 Elemental Composition of Suspended Particulate Matter ...

    African Journals Online (AJOL)

    `123456789jkl''''#

    Elemental Composition of Suspended Particulate Matter Collected at Two Different. Heights above the Ground in A Sub-Urban Site in Kenya. Gitari W. M1, Kinyua A. M. 2, Kamau G. N3 and C. K. Gatebe C. K4. Abstract. Suspended particulate matter samples were collected in a sub-urban area in Nairobi over a 12 month ...

  8. Oscillation of a diamagnetic liquid bubble suspended by magnetic force

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, R. E-mail: yamane@kokushikan.ac.jp; Tomita, S.; Mai, J.; Park, M.K.; Oshima, S

    2002-11-01

    The levitation of the diamagnetic liquid droplet with the strong magnetic field is experimentally simulated, using the magnetic fluid as the surrounding fluid in place of air or gas, and the water bubble is levitated with the conventional permanent magnet. When the stepwise magnetic field is superposed, the suspended bubble behaves as a typical step response with the overshoot and viscous damping. The effects of the volume of the bubble, the strength of the magnetic field and the concentration of the magnetic fluid are investigated.

  9. Gallium arsenide processing for gate array logic

    Science.gov (United States)

    Cole, Eric D.

    1989-01-01

    The development of a reliable and reproducible GaAs process was initiated for applications in gate array logic. Gallium Arsenide is an extremely important material for high speed electronic applications in both digital and analog circuits since its electron mobility is 3 to 5 times that of silicon, this allows for faster switching times for devices fabricated with it. Unfortunately GaAs is an extremely difficult material to process with respect to silicon and since it includes the arsenic component GaAs can be quite dangerous (toxic) especially during some heating steps. The first stage of the research was directed at developing a simple process to produce GaAs MESFETs. The MESFET (MEtal Semiconductor Field Effect Transistor) is the most useful, practical and simple active device which can be fabricated in GaAs. It utilizes an ohmic source and drain contact separated by a Schottky gate. The gate width is typically a few microns. Several process steps were required to produce a good working device including ion implantation, photolithography, thermal annealing, and metal deposition. A process was designed to reduce the total number of steps to a minimum so as to reduce possible errors. The first run produced no good devices. The problem occurred during an aluminum etch step while defining the gate contacts. It was found that the chemical etchant attacked the GaAs causing trenching and subsequent severing of the active gate region from the rest of the device. Thus all devices appeared as open circuits. This problem is being corrected and since it was the last step in the process correction should be successful. The second planned stage involves the circuit assembly of the discrete MESFETs into logic gates for test and analysis. Finally the third stage is to incorporate the designed process with the tested circuit in a layout that would produce the gate array as a GaAs integrated circuit.

  10. Aerial Photo Utilization in Estimating Suspended Sediment in the Wuryantoro Watershed, Wonogiri

    Directory of Open Access Journals (Sweden)

    Sugiharto Budi Santoso

    2004-01-01

    Full Text Available Suspended sediment load flowing out from a watershed is normally predicated by analysis os suspended sediment of water sample, and the volume of suspended sediment be calculated based on sediment concentration and river discharge. Such field measurements need a lot of field data and they are time consuming. Another method for prediction of suspended sediment by using remote sensing imagery data and recorded rainfall data. The objective of this research is to 1 examine the capability of remote sensing technique to obtain the parameters of the physical data of land in the prediction of suspended sediment; 2 examine the accuracy of the model for prediction suspended sediment. This research is carried out in Wuryantoro watershed, Wonogiri. The main data to obtain the parameters of the physical data of land is infrared aerial photograph on scale 1 : 10.000. the method that used in this research is interpretation of remote sensing imagery data, combined with rainfall data. The result show that the accuracy of landuse is 88.5%, the accuracy of slope is 87.67%. the accuracy of the prediction of suspended sediment by model A3 87.07%, model C1 86.63%, model C2 90.57%, model A8 84.13%, model A9 80.1%, and model C4 78.6%.

  11. An analysis of bedload and suspended load interactions

    Science.gov (United States)

    Recking, alain; Navratil, Oldrich

    2013-04-01

    Several approaches were used to develop suspension equations. It includes semi-theoretical equations based on the convection diffusion equation (Einstein 1950; Van Rijn 1984; Camenen and Larson 2008; Julien 2010), semi-empirical tools based on energy concept (Velikanov 1954; Bagnold 1966), empirical adjustments (Prosser and Rusttomji 2000). One essential characteristic of all these equations is that most of them were developed by considering continuity between bedload and suspended load, and that the partitioning between these two modes of transport evolves progressively with increasing shear stress, which is the case for fine bed materials. The use of these equations is thus likely to be welcome in estuaries or lowland sandy rivers, but may be questionable in gravel-bed rivers and headwater streams where the bed is usually structured vertically and fine sediments potentially contributing to suspension are stored under a poorly mobile surface armour comprising coarse sediments. Thus one question this work aimed to answer is does the presence of an armour at the bed surface influence suspended load? This was investigated through a large field data set comprising instantaneous measurements of both bedload and suspension. We also considered the river characteristics, distinguishing between lowland rivers, gravel bed rivers and headwater streams. The results showed that a correlation exist between bedload and suspension for lowland and gravel bed rivers. This suggests that in gravel bed rivers a large part of the suspended load is fed by subsurface material, and depends on the remobilization of the surface material. No correlation was observed for head water streams where the sediment production is more likely related to hillslope processes. These results were used with a bedload transport equation for proposing a method for suspended load estimate. The method is rough, but especially for gravel bed rivers, it predicts suspended load reasonably well when compared to

  12. Noisy signaling through promoter logic gates

    Science.gov (United States)

    Gerstung, Moritz; Timmer, Jens; Fleck, Christian

    2009-01-01

    We study the influence of noisy transcription factor signals on cis-regulatory promoter elements. These elements process the probability of binary binding events analogous to computer logic gates. At equilibrium, this probability is given by the so-called input function. We show that transcription factor noise causes deviations from the equilibrium value due to the nonlinearity of the input function. For a single binding site, the correction is always negative resulting in an occupancy below the mean-field level. Yet for more complex promoters it depends on the correlation of the transcription factor signals and the geometry of the input function. We present explicit solutions for the basic types of AND and OR gates. The correction size varies among these different types of gates and signal types, mainly being larger in AND gates and for correlated fluctuations. In all cases we find excellent agreement between the analytical results and numerical simulations. We also study the E. coli Lac operon as an example of an AND NOR gate. We present a consistent mathematical method that allows one to separate different sources of noise and quantifies their effect on promoter occupation. A surprising result of our analysis is that Poissonian molecular fluctuations, in contrast to external fluctuations, do no contribute to the correction.

  13. Materials Fundamentals of Gate Dielectrics

    CERN Document Server

    Demkov, Alexander A

    2006-01-01

    This book presents materials fundamentals of novel gate dielectrics that are being introduced into semiconductor manufacturing to ensure the continuous scalling of the CMOS devices. This is a very fast evolving field of research so we choose to focus on the basic understanding of the structure, thermodunamics, and electronic properties of these materials that determine their performance in device applications. Most of these materials are transition metal oxides. Ironically, the d-orbitals responsible for the high dielectric constant cause sever integration difficulties thus intrinsically limiting high-k dielectrics. Though new in the electronics industry many of these materials are wel known in the field of ceramics, and we describe this unique connection. The complexity of the structure-property relations in TM oxides makes the use of the state of the art first-principles calculations necessary. Several chapters give a detailed description of the modern theory of polarization, and heterojunction band discont...

  14. Self-aligned local electrolyte gating of 2D materials with nanoscale resolution

    CERN Document Server

    Peng, Cheng; Nanot, Sebastien; Shiue, Ren-Jye; Grosso, Gabriele; Yang, Yafang; Hempel, Marek; Jarillo-Herrero, Pablo; Kong, Jing; Koppens, Frank H L; Englund, Dirk

    2016-01-01

    In the effort to make 2D materials-based devices smaller, faster, and more efficient, it is important to control charge carrier at lengths approaching the nanometer scale. Traditional gating techniques based on capacitive coupling through a gate dielectric cannot generate strong and uniform electric fields at this scale due to divergence of the fields in dielectrics. This field divergence limits the gating strength, boundary sharpness, and pitch size of periodic structures, and restricts possible geometries of local gates (due to wire packaging), precluding certain device concepts, such as plasmonics and transformation optics based on metamaterials. Here we present a new gating concept based on a dielectric-free self-aligned electrolyte technique that allows spatially modulating charges with nanometer resolution. We employ a combination of a solid-polymer electrolyte gate and an ion-impenetrable e-beam-defined resist mask to locally create excess charges on top of the gated surface. Electrostatic simulations ...

  15. Improving suspended sediment measurements by automatic samplers.

    Science.gov (United States)

    Gettel, Melissa; Gulliver, John S; Kayhanian, Masoud; DeGroot, Gregory; Brand, Joshua; Mohseni, Omid; Erickson, Andrew J

    2011-10-01

    Suspended solids either as total suspended solids (TSS) or suspended sediment concentration (SSC) is an integral particulate water quality parameter that is important in assessing particle-bound contaminants. At present, nearly all stormwater runoff quality monitoring is performed with automatic samplers in which the sampling intake is typically installed at the bottom of a storm sewer or channel. This method of sampling often results in a less accurate measurement of suspended sediment and associated pollutants due to the vertical variation in particle concentration caused by particle settling. In this study, the inaccuracies associated with sampling by conventional intakes for automatic samplers have been verified by testing with known suspended sediment concentrations and known particle sizes ranging from approximately 20 μm to 355 μm under various flow rates. Experimental results show that, for samples collected at a typical automatic sampler intake position, the ratio of sampled to feed suspended sediment concentration is up to 6600% without an intake strainer and up to 300% with a strainer. When the sampling intake is modified with multiple sampling tubes and fitted with a wing to provide lift (winged arm sampler intake), the accuracy of sampling improves substantially. With this modification, the differences between sampled and feed suspended sediment concentration were more consistent and the sampled to feed concentration ratio was accurate to within 10% for particle sizes up to 250 μm.

  16. Low Gate Voltage Operated Multi-emitter-dot H+ Ion-Sensitive Gated Lateral Bipolar Junction Transistor

    Science.gov (United States)

    Yuan, Heng; Zhang, Ji-Xing; Zhang, Chen; Zhang, Ning; Xu, Li-Xia; Ding, Ming; Patrick, J. Clarke

    2015-02-01

    A low gate voltage operated multi-emitter-dot gated lateral bipolar junction transistor (BJT) ion sensor is proposed. The proposed device is composed of an arrayed gated lateral BJT, which is driven in the metal-oxide-semiconductor field-effect transistor (MOSFET)-BJT hybrid operation mode. Further, it has multiple emitter dots linked to each other in parallel to improve ionic sensitivity. Using hydrogen ionic solutions as reference solutions, we conduct experiments in which we compare the sensitivity and threshold voltage of the multi-emitter-dot gated lateral BJT with that of the single-emitter-dot gated lateral BJT. The multi-emitter-dot gated lateral BJT not only shows increased sensitivity but, more importantly, the proposed device can be operated under very low gate voltage, whereas the conventional ion-sensitive field-effect transistors cannot. This special characteristic is significant for low power devices and for function devices in which the provision of a gate voltage is difficult.

  17. Measurement of Suspended Sediment Transport Processes off the Holderness Coast - Southern North Sea, England

    OpenAIRE

    Blewett, Joanna Catherine

    1998-01-01

    A field campaign was set up as part of the LOIS-RACS coastal program (1994-1996), to identify the near-bed physical processes responsible for suspended sediment movement in shallow water (10-20m depth) off the Holdemess coast, NE England. A new benthic tripod system Boundary Layer Intelligent Sensor System (BLISS) has been developed and deployed along a transect at three sites, normal to the coastline at Tunstall. Measurements of current velocity, suspended sediment concentrati...

  18. Diffusion processes in freely suspended smectic films

    Science.gov (United States)

    Śliwa, I.; Zakharov, A. V.

    2017-08-01

    A molecular model describing translational diffusion in freely suspended smectic films (FSSFs) in air is proposed. This model is based on the random walk theory and allows calculation of the translational diffusion coefficient (TDC) across smectic layers (along the director). All values necessary for calculating the TDC are obtained within the generalized mean-field model considering not only anisotropic interactions between nearest neighbors of molecules forming FSSFs, but also the stabilizing effect of the smectic/air interface. The spatial inhomogeneity of order parameters over the FSSF section, arising in this case, results in the fact that the surface tension at the smectic/air interface not only suppresses thermal fluctuations in surface layers, but also completely suppresses translational diffusion of molecules from the FSSF to air. The results of calculations of dimensional translational diffusion in the bulk of the FSSF formed by 5- n-alkyl-2-(4- n-(perfluoroalkyl-metyleneoxy))pentyl molecules during its thinning show that the TDC monotonically increases as the smectic film is thinned.

  19. Approximate Series Solutions for Nonlinear Free Vibration of Suspended Cables

    Directory of Open Access Journals (Sweden)

    Yaobing Zhao

    2014-01-01

    Full Text Available This paper presents approximate series solutions for nonlinear free vibration of suspended cables via the Lindstedt-Poincare method and homotopy analysis method, respectively. Firstly, taking into account the geometric nonlinearity of the suspended cable as well as the quasi-static assumption, a mathematical model is presented. Secondly, two analytical methods are introduced to obtain the approximate series solutions in the case of nonlinear free vibration. Moreover, small and large sag-to-span ratios and initial conditions are chosen to study the nonlinear dynamic responses by these two analytical methods. The numerical results indicate that frequency amplitude relationships obtained with different analytical approaches exhibit some quantitative and qualitative differences in the cases of motions, mode shapes, and particular sag-to-span ratios. Finally, a detailed comparison of the differences in the displacement fields and cable axial total tensions is made.

  20. Stanford, Duke, Rice,... and Gates?

    Science.gov (United States)

    Carey, Kevin

    2009-01-01

    This article presents an open letter to Bill Gates. In his letter, the author suggests that Bill Gates should build a brand-new university, a great 21st-century institution of higher learning. This university will be unlike anything the world has ever seen. He asks Bill Gates not to stop helping existing colleges create the higher-education system…

  1. Analysis of gate underlap channel double gate MOS transistor for electrical detection of bio-molecules

    Science.gov (United States)

    Ajay; Narang, Rakhi; Saxena, Manoj; Gupta, Mridula

    2015-12-01

    In this paper, an analytical model for gate drain underlap channel Double-Gate Metal-Oxide-Semiconductor Field-Effect Transistor (DG-MOSFET) for label free electrical detection of biomolecules has been proposed. The conformal mapping technique has been used to derive the expressions for surface potential, lateral electric field, energy bands (i.e. conduction and valence band) and threshold voltage (Vth). Subsequently a full drain current model to analyze the sensitivity of the biosensor has been developed. The shift in the threshold voltage and drain current (after the biomolecules interaction with the gate underlap channel region of the MOS transistor) has been used as a sensing metric. All the characteristic trends have been verified through ATLAS (SILVACO) device simulation results.

  2. A Generalized Mathematical Model for the Fracture Problem of the Suspended Highway

    Directory of Open Access Journals (Sweden)

    Zhao Ying

    2017-01-01

    Full Text Available In order to answer dangling fracture problems of highway, the suspended pavement equivalent for non - suspended pavement, through the special boundary conditions has been suspended highway stress field of expression, in accordance with the 3D fracture model of crack formation, and establish a vacant, a general mathematics model for fracture problems of highway and analysis in highway suspended segment weight and vehicle load limit of highway capacity of Pu For overturning road inPu is less than the force of carrying more than compared to the work and fruit Bridge Hydropower Station Road engineering examples to verify suspended highway should force field expressions for the correctness and applicability. The results show that: when the hanging ratio R 0. 243177 limits of Pu design axle load 100kN. When the vertical crack in the vacant in the direction of length greater than 0. 1, the ultimate bearing capacity is less than the design axle load 100kN; when the hanging ratio R is less than 0. 5, the road to local fracture, the ultimate bearing capacity of suspended stress field expressions in solution; when the hanging ratio is greater than or equal to 0. 5, the road does not reach the limit bearing capacity of the whole body; torque shear surface of the effect is far less than the bending moments on shear planes.

  3. Illumination of Double Snapback Mechanism in High Voltage Operating Grounded Gate Extended Drain N-type Metal-Oxide-Semiconductor Field Effects Transistor Electro-Static Discharge Protection Devices

    Science.gov (United States)

    Kim, Kil Ho; Jung, Yong Icc; Shim, Jin Seop; So, Hyung Tae; Lee, Ji Hyun; Hwang, Lee Yeun; Park, Jin Won

    2004-10-01

    High current behaviors of the ‘grounded gate extended drain N-type metal-oxide-semiconductor field effects transistor’ (GG_EDNMOS) electro-static discharge (ESD) protection devices are analyzed. Both the transmission line pulse (TLP) data and the thermal incorporated 2-dimensional simulation analyses demonstrate a characteristic double snapback phenomenon after triggering of biploar junction transistor (BJT) operation. This implies the co-existence of two different on-states in high current region. The 2nd on-state, characterized by extremely low snapback holding voltage and low on-resistance, seems to be responsible for the vulnerability of the device under ESD stress. Simulation based contour analyses reveal that combination of BJT operation and deep electron channeling induced by high electron injection gives rise to the 2nd on-state. Thus, the deep electron channel formation needs to be prevented in order to realize stable and robust ESD protection performance. Further studies reveal that the N-drift implant dose, among various process parameters, is a critical factor to determine the formation of deep electron channeling and consequential occurrence of the 2nd on-state. Based on our analyses, general methodology to avoid the double snapback and to realize stable ESD protection is to be discussed.

  4. A Three-Dimensional Simulation Study of Source/Drain-Tied Double-Gate Fin Field-Effect Transistor Design for 16-nm Half-Pitch Technology Generation and Beyond

    Science.gov (United States)

    Eng, Yi-Chuen; Lin, Jyi-Tsong; Chang, Tzu-Feng; Chen, Chun-Yu; Fan, Yi-Hsuan; Chen, Cheng-Hsin; Lin, Po-Hsieh

    2011-08-01

    This paper presents a three-dimensional (3D) simulation study of source/drain (S/D)-tied (SDT) double-gate (DG) fin field-effect transistor (FinFET) design for 16-nm half-pitch technology generation and beyond using technology computer-aided design (TCAD) tools. A simple process to fabricate the proposed SDT FinFET is proposed. An investigation of the fin width (Wfin) on the electrical characteristics is shown, suggesting that a reduced Wfin is good for both the suppression of short-channel effects and the reduction of parasitic capacitance in SDT FinFETs. Also, the self-heating can be well controlled in our proposed SDT FinFET which is a difficult task for SOI family. The proposed FinFET is also compared with the existing experimental data, showing that the SDT FinFET not only demonstrates desired short-channel characteristics due to its inherent structure advantages (partially insulating oxide under the channel region), but also reduces the costs of device fabrication due to its simple process method and planar-like structure.

  5. High permittivity gate dielectric materials

    CERN Document Server

    2013-01-01

    "The book comprehensively covers all the current and the emerging areas of the physics and the technology of high permittivity gate dielectric materials, including, topics such as MOSFET basics and characteristics, hafnium-based gate dielectric materials, Hf-based gate dielectric processing, metal gate electrodes, flat-band and threshold voltage tuning, channel mobility, high-k gate stack degradation and reliability, lanthanide-based high-k gate stack materials, ternary hafnia and lanthania based high-k gate stack films, crystalline high-k oxides, high mobility substrates, and parameter extraction. Each chapter begins with the basics necessary for understanding the topic, followed by a comprehensive review of the literature, and ultimately graduating to the current status of the technology and our scientific understanding and the future prospects."

  6. Wide-field color imaging of scatter-based tissue contrast using both high spatial frequency illumination and cross-polarization gating.

    Science.gov (United States)

    Carlson, Mackenzie L; McClatchy, David M; Gunn, Jason R; Elliott, Jonathan T; Paulsen, Keith D; Kanick, Stephen C; Pogue, Brian W

    2017-08-11

    This study characterizes the scatter-specific tissue contrast that can be obtained by high spatial frequency (HSF) domain imaging and cross-polarization (CP) imaging, using a standard color imaging system, and how combining them may be beneficial. Both HSF and CP approaches are known to modulate the sensitivity of epi-illumination reflectance images between diffuse multiply scattered and superficially backscattered photons, providing enhanced contrast from microstructure and composition than what is achieved by standard wide-field imaging. Measurements in tissue-simulating optical phantoms show that CP imaging returns localized assessments of both scattering and absorption effects, while HSF has uniquely specific sensitivity to scatter-only contrast, with a strong suppression of visible contrast from blood. The combination of CP and HSF imaging provided an expanded sensitivity to scatter compared with CP imaging, while rejecting specular reflections detected by HSF imaging. ex vivo imaging of an atlas of dissected rodent organs/tissues demonstrated the scatter-based contrast achieved with HSF, CP and HSF-CP imaging, with the white light spectral signal returned by each approach translated to a color image for intuitive encoding of scatter-based contrast within images of tissue. The results suggest that visible CP-HSF imaging could have the potential to aid diagnostic imaging of lesions in skin or mucosal tissues and organs, where just CP is currently the standard practice imaging modality. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Surface Decoration on Polymeric Gate Dielectrics for Flexible Organic Field-Effect Transistors via Hydroxylation and Subsequent Monolayer Self-Assembly.

    Science.gov (United States)

    Yan, Yan; Huang, Long-Biao; Zhou, Ye; Han, Su-Ting; Zhou, Li; Sun, Qijun; Zhuang, Jiaqing; Peng, Haiyan; Yan, He; Roy, V A L

    2015-10-28

    A simple photochemical reaction based on confined photocatalytic oxidation (CPO) treatment and hydrolysis was employed to efficiently convert C-H bonds into C-OH groups on polymeric material surfaces, followed by investigation of monolayer self-assembly decoration on polymeric dielectrics via chemical bonding for the organic field-effect transistors (OFETs) applications. This method is a low temperature process and has negligible etching effect on polymeric dielectric layers. Various types of self-assembled monolayers have been tested and successfully attached onto the hydroxylated polymeric dielectric surfaces through chemical bonding, ensuring the stability of decorated functional films during the subsequent device fabrication consisting of solution processing of the polymer active layer. With the surface decoration of functional groups, both n-type and p-type polymers exhibit enhanced carrier mobilities in the unipolar OFETs. In addition, enhanced and balanced mobilities are obtained in the ambipolar OFETs with the blend of polymer semiconductors. The anchored self-assembled monolayers on the dielectric surfaces dramatically preclude the solvent effect, thus enabling an improvement of carrier mobility up to 2 orders of magnitude. Our study opens a way of targeted modifications of polymeric surfaces and related applications in organic electronics.

  8. Continuous-flow centrifugation to collect suspended sediment for chemical analysis

    Science.gov (United States)

    Conn, Kathleen E.; Dinicola, Richard S.; Black, Robert W.; Cox, Stephen E.; Sheibley, Richard W.; Foreman, James R.; Senter, Craig A.; Peterson, Norman T.

    2016-12-22

    Recent advances in suspended-sediment monitoring tools and surrogate technologies have greatly improved the ability to quantify suspended-sediment concentrations and to estimate daily, seasonal, and annual suspended-sediment fluxes from rivers to coastal waters. However, little is known about the chemical composition of suspended sediment, and how it may vary spatially between water bodies and temporally within a single system owing to climate, seasonality, land use, and other natural and anthropogenic drivers. Many water-quality contaminants, such as organic and inorganic chemicals, nutrients, and pathogens, preferentially partition in sediment rather than water. Suspended sediment-bound chemical concentrations may be undetected during analysis of unfiltered water samples, owing to small water sample volumes and analytical limitations. Quantification of suspended sediment‑bound chemical concentrations is needed to improve estimates of total chemical concentrations, chemical fluxes, and exposure levels of aquatic organisms and humans in receiving environments. Despite these needs, few studies or monitoring programs measure the chemical composition of suspended sediment, largely owing to the difficulty in consistently obtaining samples of sufficient quality and quantity for laboratory analysis.A field protocol is described here utilizing continuous‑flow centrifugation for the collection of suspended sediment for chemical analysis. The centrifuge used for development of this method is small, lightweight, and portable for the field applications described in this protocol. Project scoping considerations, deployment of equipment and system layout options, and results from various field and laboratory quality control experiments are described. The testing confirmed the applicability of the protocol for the determination of many inorganic and organic chemicals sorbed on suspended sediment, including metals, pesticides, polycyclic aromatic hydrocarbons, and

  9. SU-E-T-439: Fundamental Verification of Respiratory-Gated Spot Scanning Proton Beam Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hamano, H; Yamakawa, T [Graduate School of Health Sciences, Fujita Health University, Toyoake (Japan); Hayashi, N; Kato, H [School of Health Sciences, Fujita Health University, Tayoake (Japan); Yasui, K [Department of Proton Therapy Technology, Nagoya Proton Therapy Center, Nagoya (Japan)

    2015-06-15

    Purpose: The spot-scanning proton beam irradiation with respiratory gating technique provides quite well dose distribution and requires both dosimetric and geometric verification prior to clinical implementation. The purpose of this study is to evaluate the impact of gating irradiation as a fundamental verification. Methods: We evaluated field width, flatness, symmetry, and penumbra in the gated and non-gated proton beams. The respiration motion was distinguished into 3 patterns: 10, 20, and 30 mm. We compared these contents between the gated and non-gated beams. A 200 MeV proton beam from PROBEAT-III unit (Hitachi Co.Ltd) was used in this study. Respiratory gating irradiation was performed by Quasar phantom (MODUS medical devices) with a combination of dedicated respiratory gating system (ANZAI Medical Corporation). For radiochromic film dosimetry, the calibration curve was created with Gafchromic EBT3 film (Ashland) on FilmQA Pro 2014 (Ashland) as film analysis software. Results: The film was calibrated at the middle of spread out Bragg peak in passive proton beam. The field width, flatness and penumbra in non-gated proton irradiation with respiratory motion were larger than those of reference beam without respiratory motion: the maximum errors of the field width, flatness and penumbra in respiratory motion of 30 mm were 1.75% and 40.3% and 39.7%, respectively. The errors of flatness and penumbra in gating beam (motion: 30 mm, gating rate: 25%) were 0.0% and 2.91%, respectively. The results of symmetry in all proton beams with gating technique were within 0.6%. Conclusion: The field width, flatness, symmetry and penumbra were improved with the gating technique in proton beam. The spot scanning proton beam with gating technique is feasible for the motioned target.

  10. Noise Gating Solar Images

    Science.gov (United States)

    DeForest, Craig; Seaton, Daniel B.; Darnell, John A.

    2017-08-01

    I present and demonstrate a new, general purpose post-processing technique, "3D noise gating", that can reduce image noise by an order of magnitude or more without effective loss of spatial or temporal resolution in typical solar applications.Nearly all scientific images are, ultimately, limited by noise. Noise can be direct Poisson "shot noise" from photon counting effects, or introduced by other means such as detector read noise. Noise is typically represented as a random variable (perhaps with location- or image-dependent characteristics) that is sampled once per pixel or once per resolution element of an image sequence. Noise limits many aspects of image analysis, including photometry, spatiotemporal resolution, feature identification, morphology extraction, and background modeling and separation.Identifying and separating noise from image signal is difficult. The common practice of blurring in space and/or time works because most image "signal" is concentrated in the low Fourier components of an image, while noise is evenly distributed. Blurring in space and/or time attenuates the high spatial and temporal frequencies, reducing noise at the expense of also attenuating image detail. Noise-gating exploits the same property -- "coherence" -- that we use to identify features in images, to separate image features from noise.Processing image sequences through 3-D noise gating results in spectacular (more than 10x) improvements in signal-to-noise ratio, while not blurring bright, resolved features in either space or time. This improves most types of image analysis, including feature identification, time sequence extraction, absolute and relative photometry (including differential emission measure analysis), feature tracking, computer vision, correlation tracking, background modeling, cross-scale analysis, visual display/presentation, and image compression.I will introduce noise gating, describe the method, and show examples from several instruments (including SDO

  11. [Light absorption by suspended particulate matter in Chagan Lake, Jilin].

    Science.gov (United States)

    Wang, Yuan-Dong; Liu, Dian-Wei; Song, Kai-Shan; Zhang, Bai; Wang, Zong-Ming; Jiang, Guang-Ji; Tang, Xu-Guang; Lei, Xiao-Chun; Wu, Yan-Qing

    2011-01-01

    Spectral characteristics and the magnitudes of light absorption by suspended particulate matter were determined by spectrophotometry in this optically complex Lake Chagan waters for the purpose of surveying the natural variability of the absorption coefficients to parameterize the bio-optical models for converting satellite or in-situ water reflectance signatures into water quality information. Experiments were carried out on seasonal frozen Lake Chagan, one representative inland case-2 water body in Northeast of China. Particulate absorption properties analyzed using the field data on July 15th and October 12th 2009 were measured using the quantitative filter technique to produce absorption spectra containing several fractions that could be attributed to two main optical active constituents (OACs) phytoplankton pigments and non-algal particulates (mineral sediments, and organic detritus). Results suggested that the suspended particulate matter (SPM) concentration was higher while phytoplankton biomass (chlorophyll-a concentration) was lower in July and that in October. The spectral shape of total suspended particulate matter resembled that of non-algal particulates which contributed greater than phytoplankton in total particulate absorption during both periods. An obvious absorption peak occurring at around 440 nm exhibited an increase in phytoplankton contribution in October. Non-algal particulate absorption at 440 nm (a(NAP) (440)) had better correlation with total suspended particulate matter concentration than that with chlorophyll-a over the two periods. Light absorption by phytoplankton pigments in the Chagan lake region was generally lower than that of non-algal components. Chl. a dominating phytoplankton pigment composition functioned exponentially with its absorption coefficients at 440 and 675 nm specifically, the average values of which in July were 0.146 8 m2 x mg(-1) and 0.050 3 respectively while in October they were 0.153 3 and 0.013 2 m2 x mg(-1

  12. Technological advances in suspended-sediment surrogate monitoring

    Science.gov (United States)

    Gray, John R.; Gartner, Jeffrey W.

    2009-01-01

    Surrogate technologies to continuously monitor suspended sediment show promise toward supplanting traditional data collection methods requiring routine collection and analysis of water samples. Commercially available instruments operating on bulk optic (turbidity), laser optic, pressure difference, and acoustic backscatter principles are evaluated based on cost, reliability, robustness, accuracy, sample volume, susceptibility to biological fouling, and suitable range of mass concentration and particle size distribution. In situ turbidimeters are widely used. They provide reliable data where the point measurements can be reliably correlated to the river's mean cross section concentration value, effects of biological fouling can be minimized, and concentrations remain below the sensor's upper measurement limit. In situ laser diffraction instruments have similar limitations and can cost 6 times the approximate $5000 purchase price of a turbidimeter. However, laser diffraction instruments provide volumetric-concentration data in 32 size classes. Pressure differential instruments measure mass density in a water column, thus integrating substantially more streamflow than a point measurement. They are designed for monitoring medium-to-large concentrations, are generally unaffected by biological fouling, and cost about the same as a turbidimeter. However, their performance has been marginal in field applications. Acoustic Doppler profilers use acoustic backscatter to measure suspended sediment concentrations in orders of magnitude more streamflow than do instruments that rely on point measurements. The technology is relatively robust and generally immune to effects of biological fouling. Cost of a single-frequency device is about double that of a turbidimeter. Multifrequency arrays also provide the potential to resolve concentrations by clay silt versus sand size fractions. Multifrequency hydroacoustics shows the most promise for revolutionizing collection of continuous

  13. Impact of gate geometry on ionic liquid gated ionotronic systems

    Science.gov (United States)

    Wong, A. T.; Noh, J. H.; Pudasaini, P. R.; Wolf, B.; Balke, N.; Herklotz, A.; Sharma, Y.; Haglund, A. V.; Dai, S.; Mandrus, D.; Rack, P. D.; Ward, T. Z.

    2017-04-01

    Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard "side gate" 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. These findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

  14. Magnetically suspended virtual divergent channel

    Energy Technology Data Exchange (ETDEWEB)

    Yamane, Ryuichiro [Kokushikan University, 4-28-1 Setagaya, Setagaya-ku, Tokyo 154-8515 (Japan)]. E-mail: yamane@kokushikan.ac.jp; Oshiama, Shuzo [Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8552 (Japan); Park, Myeong-Kwan [Pusan National University, 30 Changjeon-dong, Kumjeong-ku, Pusan 609-735 (Korea, Republic of)

    2005-03-15

    Two permanent magnets are set face-to-face and inclined with each other to produce the long cuspidal magnetic field. The diamagnetic liquid is levitated and flows through it without contact with the solid walls as if it is in the virtual divergent channel. Analysis is made on the shape of the virtual channel, and the results are compared with the experimental ones. The divergence angle increases with the increase in the inclination of the magnets.

  15. Asymmetrical field emitter

    Science.gov (United States)

    Fleming, J.G.; Smith, B.K.

    1995-10-10

    A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

  16. Voltage Gated Ion Channel Function: Gating, Conduction, and the Role of Water and Protons

    Science.gov (United States)

    Kariev, Alisher M.; Green, Michael E.

    2012-01-01

    Ion channels, which are found in every biological cell, regulate the concentration of electrolytes, and are responsible for multiple biological functions, including in particular the propagation of nerve impulses. The channels with the latter function are gated (opened) by a voltage signal, which allows Na+ into the cell and K+ out. These channels have several positively charged amino acids on a transmembrane domain of their voltage sensor, and it is generally considered, based primarily on two lines of experimental evidence, that these charges move with respect to the membrane to open the channel. At least three forms of motion, with greatly differing extents and mechanisms of motion, have been proposed. There is a “gating current”, a capacitative current preceding the channel opening, that corresponds to several charges (for one class of channel typically 12–13) crossing the membrane field, which may not require protein physically crossing a large fraction of the membrane. The coupling to the opening of the channel would in these models depend on the motion. The conduction itself is usually assumed to require the “gate” of the channel to be pulled apart to allow ions to enter as a section of the protein partially crosses the membrane, and a selectivity filter at the opposite end of the channel determines the ion which is allowed to pass through. We will here primarily consider K+ channels, although Na+ channels are similar. We propose that the mechanism of gating differs from that which is generally accepted, in that the positively charged residues need not move (there may be some motion, but not as gating current). Instead, protons may constitute the gating current, causing the gate to open; opening consists of only increasing the diameter at the gate from approximately 6 Å to approximately 12 Å. We propose in addition that the gate oscillates rather than simply opens, and the ion experiences a barrier to its motion across the channel that is tuned

  17. Digital Fingerprinting of Field Programmable Gate Arrays

    Science.gov (United States)

    2008-03-01

    feature size necessitates a redesign and new fabrication run. As a result, the FPGA has become popular in the commercial market, and by extension in DoD...in a pseudo-computer language, VHDL or Verilog , and downloading it to the FPGA to run. Updates are as simple as adding a few new lines of code, running...television operating by 1’s and 0’s. The truth is that the world is actually analog and that the devices considered digital are, in reality, dealing

  18. Hysteresis free negative total gate capacitance in junctionless transistors

    Science.gov (United States)

    Gupta, Manish; Kranti, Abhinav

    2017-09-01

    In this work, we report on the hysteresis free impact ionization induced off-to-on transition while preserving sub-60 mV/decade Subthreshold swing (S-swing) using asymmetric mode operation in double gate silicon (Si) and germanium (Ge) junctionless (JL) transistor. It is shown that sub-60 mV/decade steep switching due to impact ionization implies a negative value of the total gate capacitance. The performance of asymmetric gate JL transistor is compared with symmetric gate operation of JL device, and the condition for hysteresis free current transition with a sub-60 mV/decade switching is analyzed through the product of current density (J) and electric field (E). It is shown that asymmetric gate operation limits the degree of impact ionization inherent in the semiconductor film to levels sufficient for negative total gate capacitance but lower than that required for the occurrence of hysteresis. The work highlights new viewpoints related to the suppression of hysteresis associated with steep switching JL transistors while maintaining S-swing within the range 6-15 mV/decade leading to the negative value of total gate capacitance.

  19. 3D modeling of dual-gate FinFET.

    Science.gov (United States)

    Mil'shtein, Samson; Devarakonda, Lalitha; Zanchi, Brian; Palma, John

    2012-11-13

    The tendency to have better control of the flow of electrons in a channel of field-effect transistors (FETs) did lead to the design of two gates in junction field-effect transistors, field plates in a variety of metal semiconductor field-effect transistors and high electron mobility transistors, and finally a gate wrapping around three sides of a narrow fin-shaped channel in a FinFET. With the enhanced control, performance trends of all FETs are still challenged by carrier mobility dependence on the strengths of the electrical field along the channel. However, in cases when the ratio of FinFET volume to its surface dramatically decreases, one should carefully consider the surface boundary conditions of the device. Moreover, the inherent non-planar nature of a FinFET demands 3D modeling for accurate analysis of the device performance. Using the Silvaco modeling tool with quantization effects, we modeled a physical FinFET described in the work of Hisamoto et al. (IEEE Tran. Elec. Devices 47:12, 2000) in 3D. We compared it with a 2D model of the same device. We demonstrated that 3D modeling produces more accurate results. As 3D modeling results came close to experimental measurements, we made the next step of the study by designing a dual-gate FinFET biased at Vg1 >Vg2. It is shown that the dual-gate FinFET carries higher transconductance than the single-gate device.

  20. Flexible suspended gate organic thin-film transistors for ultra-sensitive pressure detection

    National Research Council Canada - National Science Library

    Zang, Yaping; Zhang, Fengjiao; Huang, Dazhen; Gao, Xike; Di, Chong-An; Zhu, Daoben

    2015-01-01

    The utilization of organic devices as pressure-sensing elements in artificial intelligence and healthcare applications represents a fascinating opportunity for the next-generation electronic products...

  1. Reconfigurable Skyrmion Logic Gates.

    Science.gov (United States)

    Luo, Shijiang; Song, Min; Li, Xin; Zhang, Yue; Hong, Jeongmin; Yang, Xiaofei; Zou, Xuecheng; Xu, Nuo; You, Long

    2018-02-14

    Magnetic skyrmion, a nanosized spin texture with topological property, has become an area of significant interest due to the scientific insight that it can provide and also its potential impact on applications such as ultra-low-energy and ultra-high-density logic gates. In the quest for the reconfiguration of single logic device and the implementation of the complete logic functions, a novel reconfigurable skyrmion logic (RSL) is proposed and verified by micromagnetic simulations. Logic functions including AND, OR, NOT, NAND, NOR, XOR, and XNOR are implemented in the ferromagnetic (FM) nanotrack by virtue of various effects including spin orbit torque, skyrmion Hall effect, skyrmion-edge repulsions, and skyrmion-skyrmion collision. Different logic functions can be selected in an RSL by applying voltage to specific region(s) of the device, changing the local anisotropy energy of FM film. Material properties and geometrical scaling studies suggest RSL gates fit for energy-efficient computing as well as provide the guidelines for the design and optimization of this new logic family.

  2. Cascaded logic gates in nanophotonic plasmon networks

    National Research Council Canada - National Science Library

    Wei, Hong; Wang, Zhuoxian; Tian, Xiaorui; Käll, Mikael; Xu, Hongxing

    2011-01-01

    ... integrated logic units and cascade devices have not been reported. Here we demonstrate that a plasmonic binary NOR gate, a 'universal logic gate', can be realized through cascaded OR and NOT gates in four-terminal plasmonic nanowire networks...

  3. 9 CFR 201.81 - Suspended registrants.

    Science.gov (United States)

    2010-01-01

    ... 201.81 Animals and Animal Products GRAIN INSPECTION, PACKERS AND STOCKYARDS ADMINISTRATION (PACKERS AND STOCKYARDS PROGRAMS), DEPARTMENT OF AGRICULTURE REGULATIONS UNDER THE PACKERS AND STOCKYARDS ACT Services § 201.81 Suspended registrants. No stockyard owner, packer, market agency, or dealer shall employ...

  4. Electrodialytic remediation of suspended mine tailings

    DEFF Research Database (Denmark)

    Hansen, Henrik K.; Rojo, Adrian; Pino, Denisse

    2008-01-01

    experiment at 40 mA, with approximately 137.5 g mine tailings on dry basis. The removal for a static (baseline) experiment only amounted 15% when passing approximately the same amount of charge through 130 g of mine tailings. The use of air bubbling to keep the tailings suspended increased the removal...

  5. Environmental toxicology: Acute effects of suspended particulate ...

    African Journals Online (AJOL)

    ... from the control values were found significant at 99% confidence level. Possible inhalatory problems are thus anticipated from prolonged accumulation of the dust in the respiratory system. KEY WORDS: Environmental toxicology, Suspended particulate matter, Dust analysis, Hematological indices, Wister albino rats. Bull.

  6. Suspended sediment concentration and particle size distribution ...

    Indian Academy of Sciences (India)

    face area, shape, minerals and source) and conse- quent interaction with heavy metal concentrations. (HMCs). Recent studies have shown a growing awareness of the wider environmental significance of the suspended sediment loads transported by rivers and streams. This includes the importance of fine grain sediment in ...

  7. Environmental toxicology: Acute effects of suspended particulate ...

    African Journals Online (AJOL)

    The elemental contents of suspended particulate matter (dust) samples from Maiduguri, Nigeria, were determined which showed appreciably high levels for especially Pb, Fe, Cu, Zn, K, Ca, and. Na. Wister albino rats were exposed to graded doses of phosphate buffered saline carried dust particles. The hematological ...

  8. A depth integrated model for suspended transport

    NARCIS (Netherlands)

    Galappatti, R.

    1983-01-01

    A new depth averaged model for suspended sediment transport in open channels has been developed based on an asymptotic solution to the two dimensional convection-diffusion equation in the vertical plane. The solution for the depth averaged concentration is derived from the bed boundary condition and

  9. The Shape of Breasts Suspended in Liquid

    NARCIS (Netherlands)

    De Kleijn, S.C.; Rensen, W.H.J.

    2007-01-01

    Philips has designed an optical mammography machine. In this machine the breast is suspended into a cup in which the measurements take place. A special fluid is inserted into the cup to prevent the light from going around the breast instead of going through it but this fluid also weakens the signal.

  10. Flow Laminarization and Acceleration by Suspended Particles

    NARCIS (Netherlands)

    Bertsch, M.; Hulshof, J.; Prostokishin, V.M.

    2015-01-01

    In [Comm. Appl. Math. Comput. Sci., 4(2009), pp. 153-175], Barenblatt presents a model for partial laminarization and acceleration of shear flows by the presence of suspended particles of different sizes, and provides a formal asymptotic analysis of the resulting velocity equation. In the present

  11. Emulsifying and Suspending Properties of Enterolobium ...

    African Journals Online (AJOL)

    Background:The thermodynamic instability of emulsions and suspensions necessitate the incorporation of emulsifiers and suspending agents respectively, in order to stabilize the formulations and ensure administration of accurate doses. Objective:Enterolobium cyclocarpum gum was characterized and evaluated for its ...

  12. Counting rates modeling for PET scanners with GATE

    Energy Technology Data Exchange (ETDEWEB)

    Guez, D.; Honore, P.F.; Kerhoas, S. [CEA, DSM, DAPNIA, SPHN, F-91191 Gif Sur Yvette (France); Bataille, F.; Comtat, C.; Jan, S. [CEA, DSV, DRM, SHFJ, F-91401 Orsay (France)

    2008-07-01

    Several developments were made in the GATE simulation platform to allow accurate modeling of the count rate performances of PET scanners over a wide range of activity concentrations. A background noise module, a dead time and limited bandwidth modeling for the coincidences, and a delayed coincidence builder were added in the code. The results obtained for the modeling of the ECAT HRRT and Focus 220 scanners with the newly developed modules are discussed. They show that GATE can be used to accurately simulate the single event, prompt coincidence and delayed coincidence rates, from very low activity levels in the field of view up to levels that saturate the acquisition system. The new developments were committed into the public release of GATE, making them available for the whole community, thanks to the open source license under Which GATE is published (LGPL). (authors)

  13. Phase matching as a gate for photon entanglement

    Science.gov (United States)

    Zheltikov, A. M.

    2017-07-01

    Phase matching is shown to provide a tunable gate that helps discriminate entangled states of light generated by four-wave mixing (FWM) in optical fibers against uncorrelated photons originating from Raman scattering. Two types of such gates are discussed. Phase-matching gates of the first type are possible in the normal dispersion regime, where FWM sidebands can be widely tuned by high-order dispersion management, enhancing the ratio of the entangled-photon output to the Raman noise. The photon-entanglement gates of the second type are created by dual-pump cross-phase-modulation-induced FWM sideband generation and can be tuned by group-velocity mismatch of the pump fields.

  14. Study on effective MOSFET channel length extracted from gate capacitance

    Science.gov (United States)

    Tsuji, Katsuhiro; Terada, Kazuo; Fujisaka, Hisato

    2018-01-01

    The effective channel length (L GCM) of metal–oxide–semiconductor field-effect transistors (MOSFETs) is extracted from the gate capacitances of actual-size MOSFETs, which are measured by charge-injection-induced-error-free charge-based capacitance measurement (CIEF CBCM). To accurately evaluate the capacitances between the gate and the channel of test MOSFETs, the parasitic capacitances are removed by using test MOSFETs having various channel sizes and a source/drain reference device. A strong linear relationship between the gate-channel capacitance and the design channel length is obtained, from which L GCM is extracted. It is found that L GCM is slightly less than the effective channel length (L CRM) extracted from the measured MOSFET drain current. The reason for this is discussed, and it is found that the capacitance between the gate electrode and the source and drain regions affects this extraction.

  15. Suspended graphene with periodic dimer nanostructure on Si cavities for surface-enhanced Raman scattering applications

    Science.gov (United States)

    Ho, Hsin-Chia; Nien, Li-Wei; Li, Jia-Han; Hsueh, Chun-Hway

    2017-04-01

    Periodic gold dimer nanoantennas on a one-atomic-layer graphene sheet elevated above Si cavities were fabricated to systematically study the effects of the cavity depth on surface-enhanced Raman scattering (SERS). The periodic trend of Raman intensity as a function of the cavity depth resulting from the interference effect between the plasmonic resonance of the gold dimer and the cavity resonance of the underlying Si cavity was observed, and the electric field was greatly enhanced compared with the non-suspended system. The finite-difference time-domain method was used to simulate the interaction between the electromagnetic wave and the suspended system and to verify the observed SERS response in experiments. Our work has the advantages of combining the superior properties of graphene with suspended metallic nanostructures to result in the enhanced electric field for SERS applications.

  16. Suspended and Bedload Sand dynamics in the Mekong River Channel and Export to the Coastal Ocean

    Science.gov (United States)

    Stephens, J. D.; Di Leonardo, D. R.; Weathers, H. D., III; Allison, M. A.

    2016-02-01

    Two field campaigns were conducted in the tidal and estuarine reach of the Song Hau distributary of the Mekong River to examine the dynamics of sand transport and export to the coastal ocean. This study examines variation in suspended sand concentration and net transport with respect to changes in discharge between the October 2014 high discharge and March 2015 low discharge studies, and over semi-diurnal and spring-neap tidal cycles between Can Tho and the Tran De and Dinh An distributary channels in the Mekong Delta. Suspended sand concentrations were measured using a P-61 isokinetic suspended sediment sampler and a Sequoia Scientific LISST-100X used in vertical profiling mode. Stationary ADCP data are used to examine bed stress at cast sites. Bed load transport rates were calculated using a repeat multibeam transect methodology and dune translation rates with flow. Preliminary results indicate that suspended sand concentration increases towards the bed and is positively correlated with increasing shear stress controlled by river discharge and tides. However, sites with non-sandy bottoms, as indicated by multibeam bathymetry, have low suspended sand concentrations, suggesting a close linkage with a bed sand source. Bed load transport rates vary cross-sectionally with shear stress and are linked to dune size. Most bed load transport is taking place in or near the thalweg. The reduction in ebb flows at low discharge and the mantling of sand fields by salinity driven mud deposition, is suspected to control the low suspended sand concentrations observed in March. Results to date suggest that net sand export (suspended plus bed load) to the ocean occurs predominantly during the high discharge monsoon season.

  17. Works close to gate B

    CERN Multimedia

    GS Department

    2011-01-01

    In connection to the TRAM project, drainage works will be carried out close to gate B until the end of next week. In order to avoid access problems, if arriving by car, please use gates A and E. Department of General Infrastructure Services (GS) GS-SE Group

  18. Penn State DOE GATE Program

    Energy Technology Data Exchange (ETDEWEB)

    Anstrom, Joel

    2012-08-31

    The Graduate Automotive Technology Education (GATE) Program at The Pennsylvania State University (Penn State) was established in October 1998 pursuant to an award from the U.S. Department of Energy (U.S. DOE). The focus area of the Penn State GATE Program is advanced energy storage systems for electric and hybrid vehicles.

  19. Logic gates with ion transistors

    Science.gov (United States)

    Grebel, H.

    2017-09-01

    Electronic logic gates are the basic building blocks of every computing and micro controlling system. Logic gates are made of switches, such as diodes and transistors. Ion-selective, ionic switches may emulate electronic switches [1-8]. If we ever want to create artificial bio-chemical circuitry, then we need to move a step further towards ion-logic circuitry. Here we demonstrate ion XOR and OR gates with electrochemical cells, and specifically, with two wet-cell batteries. In parallel to vacuum tubes, the batteries were modified to include a third, permeable and conductive mid electrode (the gate), which was placed between the anode and cathode in order to affect the ion flow through it. The key is to control the cell output with a much smaller biasing power, as demonstrated here. A successful demonstration points to self-powered ion logic gates.

  20. Logic Gates with Ion Transistors

    CERN Document Server

    Grebel, Haim

    2016-01-01

    Electronic logic gates are the basic building blocks of every computing and micro controlling system. Logic gates are made of switches, such as diodes and transistors. Ion-selective, ionic switches may emulate electronic switches [1-8]. If we ever want to create artificial bio-chemical circuitry, then we need to move a step further towards ion-logic circuitry. Here we demonstrate ion XOR and OR gates with electrochemical cells, and specifically, with two wet-cell batteries. In parallel to vacuum tubes, the batteries were modified to include a third, permeable and conductive mid electrode (the gate), which was placed between the anode and cathode in order to affect the ion flow through it. The key is to control the cell output with a much smaller biasing power, as demonstrated here. A successful demonstration points to self-powered ion logic gates.

  1. Voltage-driven spintronic logic gates in graphene nanoribbons.

    Science.gov (United States)

    Zhang, WenXing

    2014-09-10

    Electronic devices lose efficacy due to quantum effect when the line-width of gate decreases to sub-10 nm. Spintronics overcome this bottleneck and logic gates are building blocks of integrated circuits. Thus, it is essential to control electronic transport of opposite spins for designing a spintronic logic gate, and spin-selective semiconductors are natural candidates such as zigzag graphene nanoribbons (ZGNR) whose edges are ferromagnetically ordered and antiferromagnetically coupled with each other. Moreover, it is necessary to sandwich ZGNR between two ferromagnetic electrodes for making a spintronic logic gate and also necessary to apply magnetic field to change the spin orientation for modulating the spin transport. By first principle calculations, we propose a method to manipulate the spin transport in graphene nanoribbons with electric field only, instead of magnetic field. We find that metal gates with specific bias nearby edges of ZGNR build up an in-plane inhomogeneous electric field which modulates the spin transport by localizing the spin density in device. The specific manipulation of spin transport we have proposed doesn't need spin-charge conversion for output and suggests a possible base for designing spintronic integrated circuit in atomic scale.

  2. Impact of gate geometry on ionic liquid gated ionotronic systems

    Directory of Open Access Journals (Sweden)

    A. T. Wong

    2017-04-01

    Full Text Available Ionic liquid electrolytes are gaining widespread application as a gate dielectric used to control ion transport in functional materials. This letter systematically examines the important influence that device geometry in standard “side gate” 3-terminal geometries plays in device performance of a well-known oxygen ion conductor. We show that the most influential component of device design is the ratio between the area of the gate electrode and the active channel, while the spacing between these components and their individual shapes has a negligible contribution. These findings provide much needed guidance in device design intended for ionotronic gating with ionic liquids.

  3. Progress towards Acoustic Suspended Sediment Transport Monitoring: Fraser River, BC

    Science.gov (United States)

    Attard, M. E.; Venditti, J. G.; Church, M. A.; Kostaschuk, R. A.

    2011-12-01

    Our ability to predict the timing and quantity of suspended sediment transport is limited because fine sand, silt and clay delivery are supply limited, requiring empirical modeling approaches of limited temporal stability. A solution is the development of continuous monitoring techniques capable of tracking sediment concentrations and grain-size. Here we examine sediment delivery from upstream sources to the lower Fraser River. The sediment budget of the lower Fraser River provides a long-term perspective of the net changes in the channels and in sediment delivery to Fraser Delta. The budget is based on historical sediment rating curves developed from data collected from 1965-1986 by the Water Survey of Canada. We explore the possibility of re-establishing the sediment-monitoring program using hydro-acoustics by evaluating the use of a 300 kHz side-looking acoustic Doppler current profiler (aDcp), mounted just downstream of the sand-gravel transition at Mission, for continuous measurement of suspended sediment transport. Complementary field observations include conventional bottle sampling with a P-63 sampler, vertical profiles with a downward-looking 600 kHz aDcp, and 1200 kHz aDcp discharge measurements. We have successfully completed calibration of the downward-looking aDcp with the P-63 samples; the side-looking aDcp signals remain under investigation. A comparison of several methods for obtaining total sediment flux indicates that suspended sediment concentration (SSC) closely follows discharge through the freshet and peaks in total SSC and sand SSC coincide with peak measurements of discharge. Low flows are dominated by fine sediment and grain size increases with higher flows. This research assesses several techniques for obtaining sediment flux and contributes to the understanding of sediment delivery to sand-bedded portions of the river.

  4. Energy content of suspended detritus from Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Sumitra-Vijayaraghavan; Royan, J.P.

    Energy components of suspended matter included phytoplankton, zooplankton and detritus inclusive of microorganisms adsorbed to detritus. Of these, detritus contributed most of the energy (98%). The average caloric content of suspended detritus...

  5. Giant magneto-photoelectric effect in suspended graphene

    Science.gov (United States)

    Sonntag, Jens; Kurzmann, Annika; Geller, Martin; Queisser, Friedemann; Lorke, Axel; Schützhold, Ralf

    2017-06-01

    We study the optical response of a suspended, monolayer graphene field-effect transistor structure in magnetic fields of up to 9 T (quantum Hall regime). With an illumination power of only 3 μW, we measure a photocurrent of up to 400 nA (without an applied bias) corresponding to a photo-responsivity of 0.13 A W-1, which we believe to be one of the highest values ever measured in single-layer graphene. We discuss possible mechanisms for generating this strong photo-response (17 electron-hole pairs per 100 incident photons). Based on our experimental findings, we believe that the most likely scenario is a ballistic two-stage process including carrier multiplication via Auger-type inelastic Coulomb scattering at the graphene edge.

  6. The suspended sentence in French Criminal Law

    Directory of Open Access Journals (Sweden)

    Jovašević Dragan

    2016-01-01

    Full Text Available From the ancient times until today, criminal law has provided different criminal sanctions as measures of social control. These coercive measures are imposed on the criminal offender by the competent court and aimed at limitting the offender's rights and freedoms or depriving the offender of certain rights and freedoms. These sanctions are applied to the natural or legal persons who violate the norms of the legal order and injure or endanger other legal goods that enjoy legal protection. In order to effectively protect social values, criminal legislations in all countries predict a number of criminal sanctions. These are: 1 imprisonment, 2 precautions, 3 safety measures, 4 penalties for juveniles, and 5 sanctions for legal persons. Apart and instead of punishment, warning measures have a significant role in the jurisprudence. Since they emerged in the early 20th century in the system of criminal sanctions, there has been an increase in their application to criminal offenders, especially when it comes to first-time offenders who committed a negligent or accidental criminal act. Warnings are applied in case of crimes that do not have serious consequences, and whose perpetrators are not hardened and incorrigible criminals. All contemporary criminal legislations (including the French legilation provide a warning measure of suspended sentence. Suspended sentence is a conditional stay of execution of sentence of imprisonment for a specified time, provided that the convicted person does not commit another criminal offense and fulfills other obligations. This sanction applies if the following two conditions are fulfilled: a forma! -which is attached to the sentence of imprisonment; and b material -which is the court assessment that the application of this sanction is justified and necessary in a particular case. In many modern criminal legislations, there are two different types of suspended (conditional sentence: 1 ordinary (classical suspended

  7. Wavelength Gated Dynamic Covalent Chemistry.

    Science.gov (United States)

    Frisch, Hendrik; Marschner, David; Goldmann, Anja; Barner-Kowollik, Christopher

    2017-10-24

    Precise control of chemical reactions constitutes the foundation of synthesis. Classically, judicious functional group choice as well as external factors such as temperature and catalysts are used to exert control, yet the recent renaissance of light as a medium to direct chemical synthesis points to the advent of a new era in enabling chemical selectivity. Light-guided reactions not only offer precise temporal and spatial control, yet critically allow to selectively address highly specific reaction channels gated by wavelength and intensity, resulting in a unique level of reaction control via covalent bonds that can be made and unmade by finely regulated photonic fields. Photoreversible cycloadditions are the most promising candidates to seize the outlined potential upon selective cyclisation and cycloreversion, yet are today still far from fulfilling these expectations. Herein, we critically explore the current challenges in the application of photoreversible cycloadditions and discuss the steps necessary to seize their potential in molecular biology, biomimetic systems, 3D laser lithographic processes and advanced soft matter materials with reprogrammable and self-healing properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Estimating total suspended sediment yield with probability sampling

    Science.gov (United States)

    Robert B. Thomas

    1985-01-01

    The ""Selection At List Time"" (SALT) scheme controls sampling of concentration for estimating total suspended sediment yield. The probability of taking a sample is proportional to its estimated contribution to total suspended sediment discharge. This procedure gives unbiased estimates of total suspended sediment yield and the variance of the...

  9. Estuarine Suspended Sediment Dynamics: Observations Derived from over a Decade of Satellite Data

    Directory of Open Access Journals (Sweden)

    Anthony Reisinger

    2017-12-01

    Full Text Available Suspended sediment dynamics of Corpus Christi Bay, Texas, USA, a shallow-water wind-driven estuary, were investigated by combining field and satellite measurements of total suspended solids (TSS. An algorithm was developed to transform 500-m Moderate Resolution Imaging Spectroradiometer (MODIS Aqua satellite reflectance data into estimated TSS values. The algorithm was developed using a reflectance ratio regression of MODIS Band 1 (red and Band 3 (green with TSS measurements (n = 54 collected by the Texas Commission on Environmental Quality for Corpus Christi Bay and other Texas estuaries. The algorithm was validated by independently collected TSS measurements during the period of 2011–2014 with an uncertainty estimate of 13%. The algorithm was applied to the period of 2002–2014 to create a synoptic time series of TSS for Corpus Christi Bay. Potential drivers of long-term variability in suspended sediment were investigated. Median and IQR composites of suspended sediments were generated for seasonal wind regimes. From this analysis it was determined that long-term, spatial patterns of suspended sediment in the estuary are related to wind-wave resuspension during the predominant northerly and prevalent southeasterly seasonal wind regimes. The impact of dredging is also apparent in long-term patterns of Corpus Christi Bay as concentrations of suspended sediments over dredge spoil disposal sites are higher and more variable than surrounding areas, which is most likely due to their less consolidated sediments and shallower depths requiring less wave energy for sediment resuspension. This study highlights the advantage of how long-synoptic time series of TSS can be used to elucidate the major drivers of suspended sediments in estuaries.

  10. Ultrafast, high precision gated integrator

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.

    1995-01-01

    An ultrafast, high precision gated integrator has been developed by introducing new design approaches that overcome the problems associated with earlier gated integrator circuits. The very high speed is evidenced by the output settling time of less than 50 ns and 20 MHz input pulse rate. The very high precision is demonstrated by the total output offset error of less than 0.2mV and the output droop rate of less than 10{mu}V/{mu}s. This paper describes the theory of this new gated integrator circuit operation. The completed circuit test results are presented.

  11. Optomechanics for thermal characterization of suspended graphene

    Science.gov (United States)

    Dolleman, Robin J.; Houri, Samer; Davidovikj, Dejan; Cartamil-Bueno, Santiago J.; Blanter, Yaroslav M.; van der Zant, Herre S. J.; Steeneken, Peter G.

    2017-10-01

    The thermal response of graphene is expected to be extremely fast due to its low heat capacity and high thermal conductivity. In this work, the thermal response of suspended single-layer graphene membranes is investigated by characterization of their mechanical motion in response to a high-frequency modulated laser. A characteristic delay time τ between the optical intensity and mechanical motion is observed, which is attributed to the time required to raise the temperature of the membrane. We find, however, that the measured time constants are significantly larger than the predicted ones based on values of the specific heat and thermal conductivity. In order to explain the discrepancy between measured and modeled τ , a model is proposed that takes a thermal boundary resistance at the edge of the graphene drum into account. The measurements provide a noninvasive way to characterize thermal properties of suspended atomically thin membranes, providing information that can be hard to obtain by other means.

  12. Fabrication and characterization of V-gate AlGaN/GaN high-electron-mobility transistors

    Science.gov (United States)

    Zhang, Kai; Cao, Meng-Yi; Chen, Yong-He; Yang, Li-Yuan; Wang, Chong; Ma, Xiao-Hua; Hao, Yue

    2013-05-01

    V-gate GaN high-electron-mobility transistors (HEMTs) are fabricated and investigated systematically. A V-shaped recess geometry is obtained using an improved Si3N4 recess etching technology. Compared with standard HEMTs, the fabricated V-gate HEMTs exhibit a 17% higher peak extrinsic transconductance due to a narrowed gate foot. Moreover, both the gate leakage and current dispersion are dramatically suppressed simultaneously, although a slight degradation of frequency response is observed. Based on a two-dimensional electric field simulation using Silvaco “ATLAS" for both standard HEMTs and V-gate HEMTs, the relaxation in peak electric field at the gate edge is identified as the predominant factor leading to the superior performance of V-gate HEMTs.

  13. Suspended sediments limit coral sperm availability

    Science.gov (United States)

    Ricardo, Gerard F.; Jones, Ross J.; Clode, Peta L.; Humanes, Adriana; Negri, Andrew P.

    2015-01-01

    Suspended sediment from dredging activities and natural resuspension events represent a risk to the reproductive processes of coral, and therefore the ongoing maintenance of reefal populations. To investigate the underlying mechanisms that could reduce the fertilisation success in turbid water, we conducted several experiments exposing gametes of the corals Acropora tenuis and A. millepora to two sediment types. Sperm limitation was identified in the presence of siliciclastic sediment (230 and ~700 mg L−1), with 2–37 fold more sperm required to achieve maximum fertilisation rates, when compared with sediment-free treatments. This effect was more pronounced at sub-optimum sperm concentrations. Considerable (>45%) decreases in sperm concentration at the water’s surface was recorded in the presence of siliciclastic sediment and a >20% decrease for carbonate sediment. Electron microscopy then confirmed sediment entangled sperm and we propose entrapment and sinking is the primary mechanism reducing sperm available to the egg. Longer exposure to suspended sediments and gamete aging further decreased fertilisation success when compared with a shorter exposure. Collectively, these findings demonstrate that high concentrations of suspended sediments effectively remove sperm from the water’s surface during coral spawning events, reducing the window for fertilisation with potential subsequent flow-on effects for recruitment. PMID:26659008

  14. Thermoelectric unipolar spin battery in a suspended carbon nanotube

    Science.gov (United States)

    Cao, Zhan; Fang, Tie-Feng; He, Wan-Xiu; Luo, Hong-Gang

    2017-04-01

    A quantum dot formed in a suspended carbon nanotube exposed to an external magnetic field is predicted to act as a thermoelectric unipolar spin battery which generates pure spin current. The built-in spin flip mechanism is a consequence of the spin-vibration interaction resulting from the interplay between the intrinsic spin-orbit coupling and the vibrational modes of the suspended carbon nanotube. On the other hand, utilizing thermoelectric effect, the temperature difference between the electron and the thermal bath to which the vibrational modes are coupled provides the driving force. We find that both magnitude and direction of the generated pure spin current are dependent on the strength of spin-vibration interaction, the sublevel configuration in dot, the temperatures of electron and thermal bath, and the tunneling rate between the dot and the pole. Moreover, in the linear response regime, the kinetic coefficient is non-monotonic in the temperature T and it reaches its maximum when {{k}\\text{B}}T is about one phonon energy. The existence of a strong intradot Coulomb interaction is irrelevant for our spin battery, provided that high-order cotunneling processes are suppressed.

  15. Thermoelectric unipolar spin battery in a suspended carbon nanotube.

    Science.gov (United States)

    Cao, Zhan; Fang, Tie-Feng; He, Wan-Xiu; Luo, Hong-Gang

    2017-04-26

    A quantum dot formed in a suspended carbon nanotube exposed to an external magnetic field is predicted to act as a thermoelectric unipolar spin battery which generates pure spin current. The built-in spin flip mechanism is a consequence of the spin-vibration interaction resulting from the interplay between the intrinsic spin-orbit coupling and the vibrational modes of the suspended carbon nanotube. On the other hand, utilizing thermoelectric effect, the temperature difference between the electron and the thermal bath to which the vibrational modes are coupled provides the driving force. We find that both magnitude and direction of the generated pure spin current are dependent on the strength of spin-vibration interaction, the sublevel configuration in dot, the temperatures of electron and thermal bath, and the tunneling rate between the dot and the pole. Moreover, in the linear response regime, the kinetic coefficient is non-monotonic in the temperature T and it reaches its maximum when [Formula: see text] is about one phonon energy. The existence of a strong intradot Coulomb interaction is irrelevant for our spin battery, provided that high-order cotunneling processes are suppressed.

  16. 49 CFR 234.223 - Gate arm.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Gate arm. 234.223 Section 234.223 Transportation... Maintenance Standards § 234.223 Gate arm. Each gate arm, when in the downward position, shall extend across... clearly viewed by approaching highway users. Each gate arm shall start its downward motion not less than...

  17. Reversible logic gates on Physarum Polycephalum

    Energy Technology Data Exchange (ETDEWEB)

    Schumann, Andrew [University of Information Technology and Management, Sucharskiego 2, Rzeszow, 35-225 (Poland)

    2015-03-10

    In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum.

  18. Demonstration of a Quantum Nondemolition Sum Gate

    DEFF Research Database (Denmark)

    Yoshikawa, J.; Miwa, Y.; Huck, Alexander

    2008-01-01

    The sum gate is the canonical two-mode gate for universal quantum computation based on continuous quantum variables. It represents the natural analogue to a qubit C-NOT gate. In addition, the continuous-variable gate describes a quantum nondemolition (QND) interaction between the quadrature compo...

  19. Characterizing the Sensitivity, Selectivity, and Reversibility of the Metal-Doped Phthalocyanine Thin-Films Used with the Interdigitated Gate Electrode Field-Effect Transistor (IGEFET) to Detect Organophosphorous Compounds and Nitrogen Dioxide

    Science.gov (United States)

    1991-12-01

    other path is through a waveguide coated with Pd. The beams are then recombined , and the resulting interference pattern is established before a...IGE #3 10 Vss IGE #3 11 Vout IGE #3 12 Vdi IGE #3 13 Floating-Gate IGE #3 14 VaTj IGE #2 15 Vbias IGE #2 16 Vss IGE #2 17 Vout IGE #2 18 VdJ IGE #2

  20. Fatigue Performance Assessment of Composite Arch Bridge Suspenders Based on Actual Vehicle Loads

    Directory of Open Access Journals (Sweden)

    Bin Chen

    2015-01-01

    Full Text Available In the through arch bridges, the suspenders are the key components connecting the arch rib and the bridge deck in the middle, and their safety is an increasing focus in the field of bridge engineering. In this study, various vehicle traffic flow parameters are investigated based on the actual vehicle data acquired from the long-term structural health monitoring system of a composite arch bridge. The representative vehicle types and the probability density functions of several parameters are determined, including the gross vehicle weight, axle weight, time headway, and speed. A finite element model of the bridge structure is constructed to determine the influence line of the cable force for various suspenders. A simulated vehicle flow, generated using the Monte Carlo method, is applied on the influence lines of the target suspender to determine the stress process, and then the stress amplitude spectrum is obtained based on the statistical analysis of the stress process using the rainflow counting method. The fatigue performance levels of various suspenders are analyzed according to the Palmgren-Miner linear cumulative damage theory, which helps to manage the safety of the suspenders.

  1. Simulating and understanding sand wave variation: a case study of the Golden Gate sand waves

    NARCIS (Netherlands)

    Sterlini-Van der Meer, Fenneke; Hulscher, Suzanne J.M.H.; Hanes, D.M

    2009-01-01

    In this paper we present a detailed comparison between measured features of the Golden Gate sand wave field and the results of a nonlinear sand wave model. Because the Golden Gate sand waves exhibit large variation in their characteristics and in their environmental physics, this area gives us the

  2. Development of paper-gate transistor toward direct detection from microbiological fluids

    Science.gov (United States)

    Kajisa, Taira; Sakata, Toshiya

    2017-04-01

    In this study, a paper-gate transistor was developed to detect glucose using an extended-gate field-effect transistor (FET). A filter paper was used as an extended gate electrode, in which Au nanoparticles (AuNPs) modified with phenylboronic acids (PBAs) were included. PBA-AuNPs play an important role as a support to not only be entrapped in cellulose fibrils but also bind to the targeted glucose in a paper. The surface properties of PBA-AuNPs were investigated to elucidate the electrical properties of the paper-gate electrode using an absorption spectrum and a zeta potential analysis. Moreover, the paper-gate electrode enabled us to detect glucose at the micromolar level on the basis of the principle of FET devices. A platform based on the paper-gate transistor is suitable for a highly sensitive system to detect glucose in trace samples such as tears, sweat, and saliva in the future.

  3. Element geochemical analysis of the contribution of aeolian sand to suspended sediment in desert stream flash floods.

    Science.gov (United States)

    Jia, Xiaopeng; Wang, Haibing

    2014-01-01

    The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

  4. Element Geochemical Analysis of the Contribution of Aeolian Sand to Suspended Sediment in Desert Stream Flash Floods

    Directory of Open Access Journals (Sweden)

    Xiaopeng Jia

    2014-01-01

    Full Text Available The interaction of wind and water in semiarid and arid areas usually leads to low-frequency flash flood events in desert rivers, which have adverse effects on river systems and ecology. In arid zones, many aeolian dune-fields terminate in stream channels and deliver aeolian sand to the channels. Although aeolian processes are common to many desert rivers, whether the aeolian processes contribute to fluvial sediment loss is still unknown. Here, we identified the aeolian-fluvial cycling process responsible for the high rate of suspended sediment transport in the Sudalaer desert stream in the Ordos plateau of China. On the basis of element geochemistry data analysis, we found that aeolian sand was similar to suspended sediment in element composition, which suggests that aeolian sand contributes to suspended sediment in flash floods. Scatter plots of some elements further confirm that aeolian sand is the major source of the suspended sediment. Factor analysis and the relation between some elements and suspended sediment concentration prove that the greater the aeolian process, the higher the suspended sediment concentration and the greater the contribution of aeolian sand to suspended sediment yield. We conclude that aeolian sand is the greatest contributor to flash floods in the Sudalaer desert stream.

  5. Bill Gates vil redde Folkeskolen

    DEFF Research Database (Denmark)

    Fejerskov, Adam Moe

    2014-01-01

    Det amerikanske uddannelsessystem bliver for tiden udsat for hård kritik, ledt an af Microsoft stifteren Bill Gates. Gates har indtil videre brugt 3 mia. kroner på at skabe opbakning til tiltag som præstationslønning af lærere og strømlining af pensum på tværs af alle skoler i landet...

  6. Tuning of the electronic characteristics of ZnO nanowire field effect transistors by proton irradiation.

    Science.gov (United States)

    Hong, Woong-Ki; Jo, Gunho; Sohn, Jung Inn; Park, Woojin; Choe, Minhyeok; Wang, Gunuk; Kahng, Yung Ho; Welland, Mark E; Lee, Takhee

    2010-02-23

    We demonstrated a controllable tuning of the electronic characteristics of ZnO nanowire field effect transistors (FETs) using a high-energy proton beam. After a short proton irradiation time, the threshold voltage shifted to the negative gate bias direction with an increase in the electrical conductance, whereas the threshold voltage shifted to the positive gate bias direction with a decrease in the electrical conductance after a long proton irradiation time. The electrical characteristics of two different types of ZnO nanowires FET device structures in which the ZnO nanowires are placed on the substrate or suspended above the substrate and photoluminescence (PL) studies of the ZnO nanowires provide substantial evidence that the experimental observations result from the irradiation-induced charges in the bulk SiO(2) and at the SiO(2)/ZnO nanowire interface, which can be explained by a surface-band-bending model in terms of gate electric field modulation. Our study on the proton-irradiation-mediated functionalization can be potentially interesting not only for understanding the proton irradiation effects on nanoscale devices, but also for creating the property-tailored nanoscale devices.

  7. Latest design of gate valves

    Energy Technology Data Exchange (ETDEWEB)

    Kurzhofer, U.; Stolte, J.; Weyand, M.

    1996-12-01

    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  8. Hydromagnetic thermosolutal instability of compressible walters' (model B' rotating fluid permeated with suspended particles in porous medium

    Directory of Open Access Journals (Sweden)

    G Rana

    2016-09-01

    Full Text Available The thermosolutal instability of compressible Walters' (model B' elastico-viscous rotating fluid permeated with suspended particles (fine dust in the presence of vertical magnetic field in porous medium is considered. By applying normal mode analysis method, the dispersion relation has been derived and solved analytically. It is observed that the rotation, magnetic field, suspended particles and viscoelasticity introduce oscillatory modes. For stationary convection the Walters' (model B' fluid behaves like an ordinary Newtonian fluid and it is observed that the rotation and stable solute gradient has stabilizing effects and suspended particles are found to have destabilizing effect on the system, whereas the medium permeability has stabilizing or destabilizing effect on the system under certain conditions. The magnetic field has destabilizing effect in the absence of rotation, whereas in the presence of rotation, magnetic field has stabilizing or destabilizing effect under certain conditions.

  9. EFFECT OF SUSPENDED PARTICLES ON THERMAL CONVECTION IN RIVLIN-ERICKSEN FLUID IN A DARCY-BRINKMAN POROUS MEDIUM

    Directory of Open Access Journals (Sweden)

    G.C. Rana

    2012-06-01

    Full Text Available In this paper, the effect of suspended particles on thermal convection in an incompressible Rivlin-Ericksen elastico-viscous fluid in a porous medium is considered. For the porous medium, the Brinkman model is employed. By applying a normal mode analysis method, the dispersion relation has been derived and solved analytically. It is observed that the medium permeability, suspended particles, gravity field and viscoelasticity introduce oscillatory modes. For stationary convection, it is observed that the Darcy number has a stabilising effect, whereas the suspended particles and medium permeability have destabilising effects on the system. The effects of suspended particles, the Darcy number and the medium permeability have been presented graphically to depict the stability characteristics, which are in good agreement with the results derived analytically.

  10. Thermosolutal Convection in Compressible Walters' (Model B′ Fluid Permeated with Suspended Particles in a Brinkman Porous Medium

    Directory of Open Access Journals (Sweden)

    G. C. Rana

    2012-06-01

    Full Text Available In this paper, the thermosolutal convection in compressible Walters' (model B′ elastico-viscous fluid permeated with suspended particles in a porous medium is considered. For the porous medium, the Brinkman model is employed. By applying normal mode analysis method, the dispersion relation has been derived and solved analytically. It is observed that the medium permeability, suspended particles, gravity field and viscoelasticity introduce oscillatory modes. For stationary convection, it is observed that the Darcy number and stable solute gradient have stabilizing effects whereas the suspended particles and medium permeability has destabilizing effects on the system. The effects of Darcy number, stable solute gradient, suspended particles and medium permeability has also been shown graphically.

  11. Monitoring of suspended sediment in South Tyrol

    Science.gov (United States)

    Nadalet, Rudi; Dinale, Roberto; Pernter, Martin; Maraldo, Luca; Peterlin, Dieter; Richter, Arnold; Comiti, Francesco

    2016-04-01

    In the context of the EU Water Framework Directive (WFD), which aims to achieve a good status of European water bodies, the Hydrographic Office of the Autonomous Province of Bolzano (Italy) extended in 2014 its institutional activities including the monitoring of suspended sediment in the river channel network. Currently, the only active monitoring station is on the Adige River at the gauging station of Ponte Adige near Bolzano (drainage area 2705 km2). The applied monitoring strategy and the data analysis concept are both based on the guidelines issued by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW). The results indicates that the temporal variability strongly differs during the investigated period (2014-2015). In addition to the analysis of precipitation and water discharge, temperature and lightning activity were also included to better understand the sediment transport dynamics observed at the station. In summer 2015, the combination of constantly high daily temperature throughout the Adige basin (which drove intense glacier melting in the headwaters) with a high frequency of convective rainfall events (90% more than in 2014, obtained through lightning detection), led to an annual mass of transported suspended sediment of 260000 t. Interestingly, this value is similar to the one estimated for 2014 (300000 t), which was characterized by very different meteorological conditions (colder and wetter summer), but with the occurrence of an important flood in August, which transported half of the annual amount. Finally, we can conclude that the adopted monitoring strategy is applicable for institutional aims in terms of costs as well as in terms of time effort. During the next years, other stations for suspended sediment monitoring are planned to be installed in the Province to cover the most important river segments.

  12. Gated grid system used with a time projection chamber

    Science.gov (United States)

    Bryman, D. A.; Leitch, M.; Navon, I.; Numao, T.; Schlatter, P.; Dixit, M. S.; Hargrove, C. K.; Mes, H.; MacDonald, J. A.; Skegg, R.; Spuller, J.; Burnham, R. A.; Hasinoff, M.; Poutissou, J.-M.; Azuelos, G.; Depommier, P.; Martin, J.-P.; Poutissou, R.; Blecher, M.; Gotow, K.; Carter, A. L.

    1985-01-01

    A gated grid system has been developed for the TRIUMF time projection chamber to suppress drift field distortions caused by positive produced at the endcap proportional wires. Good spatial resolution in the TPC has been thereby maintained over a large range of counting rates.

  13. Gated grid system used with a time projection chamber

    Energy Technology Data Exchange (ETDEWEB)

    Bryman, D.A.; Leitch, M.; Navon, I.; Numao, T.; Schlatter, P. (British Columbia Univ., Vancouver (Canada). TRIUMF Facility; Victoria Univ., British Columbia (Canada)); Dixit, M.S.; Hargrove, C.K.; Mes, H. (National Research Council of Canada, Ottawa, Ontario); MacDonald, J.A.

    1985-01-15

    A gated grid system has been developed for the TRIUMF time projection chamber to suppress drift field distortions caused by positive ions produced at the endcap proportional wires. Good spatial resolution in the TPC has been thereby maintained over a large range of counting rates.

  14. Active noise cancellation in a suspended interferometer

    CERN Document Server

    Driggers, Jennifer C; Pepper, Keenan; Adhikari, Rana

    2011-01-01

    We demonstrate feed-forward vibration isolation on a suspended Fabry-Perot interferometer using Wiener filtering and a variant of the common Least Mean Square (LMS) adaptive filter algorithm. We compare the experimental results with theoretical estimates of the cancellation efficiency. Using data from the recent LIGO Science Run, we also estimate the impact of this technique on full scale gravitational wave interferometers. In the future, we expect to use this technique to also remove acoustic, magnetic, and gravitational noise perturbations from the LIGO interferometers. This noise cancellation technique is simple enough to implement in standard laboratory environments and can be used to improve SNR for a variety of high precision experiments.

  15. Safety Harness For Work Under Suspended Load

    Science.gov (United States)

    Sunoo, Su Young

    1994-01-01

    Safety device protects worker under suspended engine or other heavy load. Mechanically linked with load so if load should fall, worker yanked safely away. Worker wears chest-plate vest with straps crossing eye on back. Lower safety cable connected to eye extends horizontally away from worker to nearby wall, wrapped on pulley and extends upward to motion amplifier or reducer. Safety cables transform any sudden downward motion of overhanging load into rapid sideways motion of worker. Net catches worker, preventing worker from bumping against wall.

  16. Annulled van der Waals interaction and nanosecond Rydberg quantum gates

    CERN Document Server

    Shi, Xiao-Feng

    2016-01-01

    A pair of neutral atoms separated by several microns and prepared in identical s-states of large principal quantum number experience a van der Waals interaction. If microwave fields are used to generate a superposition of s-states with different principal quantum numbers, a null point may be found at which a specific superposition state experiences no van der Waals interaction. An application of this novel Rydberg state in a quantum controlled-Z gate is proposed, which takes advantage of GHz rate transitions to nearby Rydberg states. A gate operation time in the tens of nanoseconds is predicted.

  17. Designing single-qutrit quantum gates via tripod adiabatic passage

    Directory of Open Access Journals (Sweden)

    M. Amniat-Talab

    2014-04-01

    Full Text Available In this paper, we use stimulated Raman adiabatic passage technique to implement single-qutrit quantum gates in tripod systems. It is shown by using the Morris-Shore (MS transformation, the six-state problem with 5 pulsed fields can be reduced to a basis that decouples two states from the others. This imposes three pulses not connected to the initial condition with have the same shape. Using this method, the six-state penta-pod system is reduced to a tripod system. We can design single-qutrit quantum gates by ignoring the fragile dynamical phase, and by suitable design of Rabi frequencies of the effective Hamiltonian

  18. Sensory gating in primary insomnia.

    Science.gov (United States)

    Hairston, Ilana S; Talbot, Lisa S; Eidelman, Polina; Gruber, June; Harvey, Allison G

    2010-06-01

    Although previous research indicates that sleep architecture is largely intact in primary insomnia (PI), the spectral content of the sleeping electroencephalographic trace and measures of brain metabolism suggest that individuals with PI are physiologically more aroused than good sleepers. Such observations imply that individuals with PI may not experience the full deactivation of sensory and cognitive processing, resulting in reduced filtering of external sensory information during sleep. To test this hypothesis, gating of sensory information during sleep was tested in participants with primary insomnia (n = 18) and good sleepers (n = 20). Sensory gating was operationally defined as (i) the difference in magnitude of evoked response potentials elicited by pairs of clicks presented during Wake and Stage II sleep, and (ii) the number of K complexes evoked by the same auditory stimulus. During wake the groups did not differ in magnitude of sensory gating. During sleep, sensory gating of the N350 component was attenuated and completely diminished in participants with insomnia. P450, which occurred only during sleep, was strongly gated in good sleepers, and less so in participants with insomnia. Additionally, participants with insomnia showed no stimulus-related increase in K complexes. Thus, PI is potentially associated with impaired capacity to filter out external sensory information, especially during sleep. The potential of using stimulus-evoked K complexes as a biomarker for primary insomnia is discussed.

  19. Gate length variation effect on performance of gate-first self-aligned In₀.₅₃Ga₀.₄₇As MOSFET.

    Science.gov (United States)

    Mohd Razip Wee, Mohd F; Dehzangi, Arash; Bollaert, Sylvain; Wichmann, Nicolas; Majlis, Burhanuddin Y

    2013-01-01

    A multi-gate n-type In₀.₅₃Ga₀.₄₇As MOSFET is fabricated using gate-first self-aligned method and air-bridge technology. The devices with different gate lengths were fabricated with the Al2O3 oxide layer with the thickness of 8 nm. In this letter, impact of gate length variation on device parameter such as threshold voltage, high and low voltage transconductance, subthreshold swing and off current are investigated at room temperature. Scaling the gate length revealed good enhancement in all investigated parameters but the negative shift in threshold voltage was observed for shorter gate lengths. The high drain current of 1.13 A/mm and maximum extrinsic transconductance of 678 mS/mm with the field effect mobility of 364 cm(2)/Vs are achieved for the gate length and width of 0.2 µm and 30 µm, respectively. The source/drain overlap length for the device is approximately extracted about 51 nm with the leakage current in order of 10(-8) A. The results of RF measurement for cut-off and maximum oscillation frequency for devices with different gate lengths are compared.

  20. Gate Length Variation Effect on Performance of Gate-First Self-Aligned In0.53Ga0.47As MOSFET

    Science.gov (United States)

    Mohd Razip Wee, Mohd F.; Dehzangi, Arash; Bollaert, Sylvain; Wichmann, Nicolas; Majlis, Burhanuddin Y.

    2013-01-01

    A multi-gate n-type In0.53Ga0.47As MOSFET is fabricated using gate-first self-aligned method and air-bridge technology. The devices with different gate lengths were fabricated with the Al2O3 oxide layer with the thickness of 8 nm. In this letter, impact of gate length variation on device parameter such as threshold voltage, high and low voltage transconductance, subthreshold swing and off current are investigated at room temperature. Scaling the gate length revealed good enhancement in all investigated parameters but the negative shift in threshold voltage was observed for shorter gate lengths. The high drain current of 1.13 A/mm and maximum extrinsic transconductance of 678 mS/mm with the field effect mobility of 364 cm2/Vs are achieved for the gate length and width of 0.2 µm and 30µm, respectively. The source/drain overlap length for the device is approximately extracted about 51 nm with the leakage current in order of 10−8 A. The results of RF measurement for cut-off and maximum oscillation frequency for devices with different gate lengths are compared. PMID:24367548

  1. SUSPENDED AND DISSOLVED MATTER FLUXES IN THE UPPER SELENGA RIVER BASIN

    Directory of Open Access Journals (Sweden)

    Sergey Chalov

    2012-01-01

    Full Text Available We synthesized recent field-based estimates of the dissolved ions (K+ Na+ Ca2+ Mg2+ Cl- SO42- HCO3-, biogens (NO3-, NO2-, PO43-(C, mg/l, heavy metal (Fesum, Mn, Pb and dissolved load (DL, kg/day, as far as suspended sediment concentration (SSC, mg/l and suspended load (SL, kg/day along upper Selenga river and its tributaries based on literature review and preliminary results of our 2011 field campaign. The crucial task of this paper is to provide full review of Russian, Mongolian and English-language literature which concern the matter fluxes in the upper part of Selenga river (within Mongolia. The exist estimates are compared with locations of 3 main matter sources within basin: mining and industry, river-bank erosion and slope wash. The heaviest increase of suspended and dissolved matter transport is indicated along Tuul-Orkhon river system (right tributary of the Selenga River where Mongolia capital Ulanbaatar, gold mine Zaamar and few other mines are located. In measurement campaigns conducted in 2005, 2006 and 2008 the increase directly after the Zaamar mining site was between 167 to 383 kg/day for Fe, between 15 and 5260 kg/day for Mn. Our field campaign indicated increase of suspended load along Tuul river from 4280 kg/day at the upstream point to 712000 kg/day below Ulaanbaatar and Zaamar. The results provide evidence on a potential connection between increased dissolved and suspended matter fluxes in transboundary rivers and zones of matter supply at industrial and mining centers, along eroded river banks and pastured lands. The gaps in the understanding of matter load fluxes within this basin are discussed with regards to determining further goals of hydrological and geochemical surveys.

  2. Elastic properties of suspended multilayer WSe2

    Science.gov (United States)

    Zhang, Rui; Koutsos, Vasileios; Cheung, Rebecca

    2016-01-01

    We report the experimental determination of the elastic properties of suspended multilayer WSe2, a promising two-dimensional (2D) semiconducting material combined with high optical quality. The suspended WSe2 membranes have been fabricated by mechanical exfoliation of bulk WSe2 and transfer of the exfoliated multilayer WSe2 flakes onto SiO2/Si substrates pre-patterned with hole arrays. Then, indentation experiments have been performed on these membranes with an atomic force microscope. The results show that the 2D elastic modulus of the multilayer WSe2 membranes increases linearly while the prestress decreases linearly as the number of layers increases. The interlayer interaction in WSe2 has been observed to be strong enough to prevent the interlayer sliding during the indentation experiments. The Young's modulus of multilayer WSe2 (167.3 ± 6.7 GPa) is statistically independent of the thickness of the membranes, whose value is about two thirds of other most investigated 2D semiconducting transition metal dichalcogenides, namely, MoS2 and WS2. Moreover, the multilayer WSe2 can endure ˜12.4 GPa stress and ˜7.3% strain without fracture or mechanical degradation. The 2D WSe2 can be an attractive semiconducting material for application in flexible optoelectronic devices and nano-electromechanical systems.

  3. Method for forming suspended micromechanical structures

    Science.gov (United States)

    Fleming, James G.

    2000-01-01

    A micromachining method is disclosed for forming a suspended micromechanical structure from {111} crystalline silicon. The micromachining method is based on the use of anisotropic dry etching to define lateral features of the structure which are etched down into a {111}-silicon substrate to a first etch depth, thereby forming sidewalls of the structure. The sidewalls are then coated with a protection layer, and the substrate is dry etched to a second etch depth to define a spacing of the structure from the substrate. A selective anisotropic wet etchant (e.g. KOH, EDP, TMAH, NaOH or CsOH) is used to laterally undercut the structure between the first and second etch depths, thereby forming a substantially planar lower surface of the structure along a {111} crystal plane that is parallel to an upper surface of the structure. The lateral extent of undercutting by the wet etchant is controlled and effectively terminated by either timing the etching, by the location of angled {111}-silicon planes or by the locations of preformed etch-stops. This present method allows the formation of suspended micromechanical structures having large vertical dimensions and large masses while allowing for detailed lateral features which can be provided by dry etch definition. Additionally, the method of the present invention is compatible with the formation of electronic circuitry on the substrate.

  4. On the Evaluation of Gate Dielectrics for 4H-SiC Based Power MOSFETs

    Directory of Open Access Journals (Sweden)

    Muhammad Nawaz

    2015-01-01

    Full Text Available This work deals with the assessment of gate dielectric for 4H-SiC MOSFETs using technology based two-dimensional numerical computer simulations. Results are studied for variety of gate dielectric candidates with varying thicknesses using well-known Fowler-Nordheim tunneling model. Compared to conventional SiO2 as a gate dielectric for 4H-SiC MOSFETs, high-k gate dielectric such as HfO2 reduces significantly the amount of electric field in the gate dielectric with equal gate dielectric thickness and hence the overall gate current density. High-k gate dielectric further reduces the shift in the threshold voltage with varying dielectric thicknesses, thus leading to better process margin and stable device operating behavior. For fixed dielectric thickness, a total shift in the threshold voltage of about 2.5 V has been observed with increasing dielectric constant from SiO2 (k=3.9 to HfO2 (k=25. This further results in higher transconductance of the device with the increase of the dielectric constant from SiO2 to HfO2. Furthermore, 4H-SiC MOSFETs are found to be more sensitive to the shift in the threshold voltage with conventional SiO2 as gate dielectric than high-k dielectric with the presence of interface state charge density that is typically observed at the interface of dielectric and 4H-SiC MOS surface.

  5. Visible-light-enhanced gating effect at the LaAlO3/SrTiO3 interface

    DEFF Research Database (Denmark)

    Lei, Y.; Li, Y.; Chen, Yunzhong

    2014-01-01

    Electrostatic gating field and light illumination are two widely used stimuli for semiconductor devices. Via capacitive effect, a gate field modifies the carrier density of the devices, while illumination generates extra carriers by exciting trapped electrons. Here we report an unusual illumination......-enhanced gating effect in a two-dimensional electron gas at the LaAlO3/SrTiO3 interface, which has been the focus of emergent phenomena exploration. We found that light illumination decreases, rather than increases, the carrier density of the gas when the interface is negatively gated through the SrTiO3 layer...

  6. Design and simulation of plasmonic interference-based majority gate

    Directory of Open Access Journals (Sweden)

    Jonas Doevenspeck

    2017-06-01

    Full Text Available Major obstacles in current CMOS technology, such as the interconnect bottleneck and thermal heat management, can be overcome by employing subwavelength-scaled light in plasmonic waveguides and devices. In this work, a plasmonic structure that implements the majority (MAJ gate function is designed and thoroughly studied through simulations. The structure consists of three merging waveguides, serving as the MAJ gate inputs. The information of the logic signals is encoded in the phase of transmitted surface plasmon polaritons (SPP. SPPs are excited at all three inputs and the phase of the output SPP is determined by the MAJ of the input phases. The operating dimensions are identified and the functionality is verified for all input combinations. This is the first reported simulation of a plasmonic MAJ gate and thus contributes to the field of optical computing at the nanoscale.

  7. Design and simulation of plasmonic interference-based majority gate

    Science.gov (United States)

    Doevenspeck, Jonas; Zografos, Odysseas; Gurunarayanan, Surya; Lauwereins, R.; Raghavan, P.; Sorée, B.

    2017-06-01

    Major obstacles in current CMOS technology, such as the interconnect bottleneck and thermal heat management, can be overcome by employing subwavelength-scaled light in plasmonic waveguides and devices. In this work, a plasmonic structure that implements the majority (MAJ) gate function is designed and thoroughly studied through simulations. The structure consists of three merging waveguides, serving as the MAJ gate inputs. The information of the logic signals is encoded in the phase of transmitted surface plasmon polaritons (SPP). SPPs are excited at all three inputs and the phase of the output SPP is determined by the MAJ of the input phases. The operating dimensions are identified and the functionality is verified for all input combinations. This is the first reported simulation of a plasmonic MAJ gate and thus contributes to the field of optical computing at the nanoscale.

  8. Organic nano-floating-gate transistor memory with metal nanoparticles.

    Science.gov (United States)

    Van Tho, Luu; Baeg, Kang-Jun; Noh, Yong-Young

    2016-01-01

    Organic non-volatile memory is advanced topics for various soft electronics applications as lightweight, low-cost, flexible, and printable solid-state data storage media. As a key building block, organic field-effect transistors (OFETs) with a nano-floating gate are widely used and promising structures to store digital information stably in a memory cell. Different types of nano-floating-gates and their various synthesis methods have been developed and applied to fabricate nanoparticle-based non-volatile memory devices. In this review, recent advances in the classes of nano-floating-gate OFET memory devices using metal nanoparticles as charge-trapping sites are briefly reviewed. Details of device fabrication, characterization, and operation mechanisms are reported based on recent research activities reported in the literature.

  9. Comparative study of predatory responses in blue mussels (Mytilus edulis L.) produced in suspended long line cultures or collected from natural bottom mussel beds

    DEFF Research Database (Denmark)

    Christensen, Helle Torp; Dolmer, Per; Petersen, Jens Kjerulf

    2011-01-01

    is the availability of seed mussels collected with minimum impact on the benthic ecosystem. To examine whether mussels collected in suspended cultures can be used for bottom culture production and as tool in habitat improvement, the differences in predatory defence responses between suspended and bottom mussels...... exposed to the predatory shore crab (Carcinus maenas L.) were tested in laboratory experiments and in the field. Predatory defence responses (byssal attachment and aggregation) and morphological traits were tested in laboratory, while growth and mortality were examined in field experiments. Suspended...

  10. Ionic thermoelectric gating organic transistors

    Science.gov (United States)

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (∼100 μV K−1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (∼10,000 μV K−1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins. PMID:28139738

  11. Design of a Ferroelectric Programmable Logic Gate Array

    Science.gov (United States)

    MacLeod, Todd C.; Ho, Fat Duen

    2003-01-01

    A programmable logic gate array has been designed utilizing ferroelectric field effect transistors. The design has only a small number of gates, but this could be scaled up to a more useful size. Using FFET's in a logic array gives several advantages. First, it allows real-time programmability to the array to give high speed reconfiguration. It also allows the array to be configured nearly an unlimited number of times, unlike a FLASH FPGA. Finally, the Ferroelectric Programmable Logic Gate Array (FPLGA) can be implemented using a smaller number of transistors because of the inherent logic characteristics of an FFET. The device was only designed and modeled using Spice models of the circuit, including the FFET. The actual device was not produced. The design consists of a small array of NAND and NOR logic gates. Other gates could easily be produced. They are linked by FFET's that control the logic flow. Timing and logic tables have been produced showing the array can produce a variety of logic combinations at a real time usable speed. This device could be a prototype for a device that could be put into imbedded systems that need the high speed of hardware implementation of logic and the complexity to need to change the logic algorithm. Because of the non-volatile nature of the FFET, it would also be useful in situations that needed to program a logic array once and use it repeatedly after the power has been shut off.

  12. Environmentally-suspended sediment production of the Nasia River ...

    African Journals Online (AJOL)

    The study assessed the level of suspended sediment produced in the Nasia River Basin. Hydrological and meteorological data and water samples were used for the study. Average suspended sediment yield (33 years) in the basin was 19.90 t/km2/yr. With mean annual runoff of 439.13m3/s, 322.43 t/yr suspended sediment ...

  13. Respiratory gating in cardiac PET

    DEFF Research Database (Denmark)

    Lassen, Martin Lyngby; Rasmussen, Thomas; Christensen, Thomas E

    2017-01-01

    BACKGROUND: Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim...... stress (82)RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4.......7) min(-1), P PET...

  14. Effects of electrolyte gating on photoluminescence spectra of large-area WSe2monolayer films

    KAUST Repository

    Matsuki, Keiichiro

    2016-05-24

    We fabricated electric double-layer transistors comprising large-area WSe2 monolayers and investigated the effects of electrolyte gating on their photoluminescence (PL) spectra. Using the efficient gating effects of electric double layers, we succeeded in the application of a large electric field (>107Vcm%1) and the accumulation of high carrier density (>1013cm%2). As a result, we observed PL spectra based on both positively and negatively charged excitons and their gate-voltage-dependent redshifts, suggesting the effects of both an electric field and charge accumulation. © 2016 The Japan Society of Applied Physics.

  15. On controlling the electronic states of shallow donors using a finite-size metal gate

    Energy Technology Data Exchange (ETDEWEB)

    Levchuk, E. A., E-mail: liauchuk@bsu.by; Makarenko, L. F. [Belarusian State University (Belarus)

    2016-01-15

    The effect of an external electric field on the states of a shallow donor near a semiconductor surface is numerically simulated. A disk-shaped metal gate is considered as an electric-field source. The wavefunctions and energies of bound states are determined by the finite-element method. The critical characteristics of electron relocation between the donor and gate are determined for various gate diameters and boundary conditions, taking into account dielectric mismatch. The empirical dependences of these characteristics on the geometrical parameters and semiconductor properties are obtained. A simple trial function is proposed, which can be used to calculate the critical parameters using the Ritz variational method.

  16. Gate-Tunable Landau Level Filling and Spectroscopy in Coupled Massive and Massless Electron Systems.

    Science.gov (United States)

    Cheng, Bin; Wu, Yong; Wang, Peng; Pan, Cheng; Taniguchi, T; Watanabe, K; Bockrath, M

    2016-07-08

    We report transport studies on coupled massive and massless electron systems, realized using twisted monolayer-graphene-natural bilayer-graphene stacks. We incorporate the layers in a dual-gated transistor geometry enabling independently tuning their charge density and the perpendicular electric field. In a perpendicular magnetic field, we observe a distinct pattern of gate-tunable Landau level crossings. Screening and interlayer electron-electron interactions yield a nonlinear monolayer gate capacitance. Data analysis enables determination of the monolayer's Fermi velocity and the bilayer's effective mass. The mass obtained is larger than that expected for isolated bilayers, suggesting that the interlayer interactions renormalize the band structure.

  17. Suspended sediment yield in Texas watersheds

    Science.gov (United States)

    Coonrod, Julia Ellen Allred

    The Texas Water Development Board collected suspended sediment samples across the state of Texas for approximately 60 years. Until this research, no comprehensive analysis of the data had been conducted. This study compiles the suspended sediment data along with corresponding streamflow and rainfall. GIS programs are developed which characterize watersheds corresponding to the sediment gauging stations. The watersheds are characterized according to topography, climate, soils, and land use. All of the data is combined to form several SAS data sets which can subsequently be analyzed using regression. Annual data for all of the stations across the state are classified temporally and spatially to determine trends in the sediment yield. In general, the suspended sediment load increases with increasing runoff but no correlation exists with rainfall. However, the annual average rainfall can be used to classify the watersheds according to climate, which improves the correlation between sediment load and runoff. The watersheds with no dams have higher sediment loads than watersheds with dams. Dams in the drier parts of Texas reduce the sediment load more than dams in the wetter part of the state. Sediment rating curves are developed separately for each basin in Texas. All but one of the curves fall into a band which varies by about two orders of magnitude. The study analyzes daily time series data for the Lavaca River near Edna station. USGS data are used to improve the sediment rating curve by the addition of physically related variables and interaction terms. The model can explain an additional 41% of the variability in sediment concentration compared to a simple bivariate regression of sediment load and flow. The TWDB daily data for the Lavaca River near Edna station are used to quantify temporal trends. There is a high correlation between sediment load and flowrate for the Lavaca River. The correlation can be improved by considering a flow-squared term and by

  18. Variations of Contact Resistance in Dual-Gated Monolayer Molybdenum Disulfide Transistors Depending on Gate Bias Selection

    Science.gov (United States)

    Tran, P. X.

    2017-06-01

    Monolayer molybdenum disulfide (MoS2) is considered an alternative two-dimensional material for high performance ultra-thin field-effect transistors. MoS2 is a triple atomic layer with a direct 1.8 eV bandgap. Bulk MoS2 has an additional indirect bandgap of 1.2 eV, which leads to high current on/off ratio around 108. Flakes of MoS2 can be obtained by mechanical exfoliation or grown by chemical vapor deposition. Intrinsic cut-off frequency of multilayer MoS2 transistor has reached 42 GHz. Chemical doping of MoS2 is challenging and results in reduction of contact resistance. This paper focuses on modeling of dual-gated monolayer MoS2 transistors with effective mobility of carriers varying from 0.6 cm2/V s to 750 cm2/V s. In agreement with experimental data, the model demonstrates that in back-gate bias devices, the contact resistance decreases almost exponentially with increasing gate bias, whereas in top-gate bias devices, the contact resistance stays invariant when varying gate bias.

  19. Reversible logic gate using adiabatic superconducting devices

    National Research Council Canada - National Science Library

    Takeuchi, N; Yamanashi, Y; Yoshikawa, N

    2014-01-01

    .... However, until now, no practical reversible logic gates have been demonstrated. One of the problems is that reversible logic gates must be built by using extremely energy-efficient logic devices...

  20. Thematic mapper research in the earth sciences: Small scale patches of suspended matter and phytoplankton in the Elbe River Estuary, German Bight and Tidal Flats

    Science.gov (United States)

    Grassl, H.; Doerffer, R.; Fischer, J.; Brockmann, C.; Stoessel, M.

    1987-01-01

    A Thematic Mapper (TM) field experiment was followed by a data analysis to determine TM capabilities for analysis of suspended matter and phytoplankton. Factor analysis showed that suspended matter concentration, atmospheric scattering, and sea surface temperature can be retrieved as independent factors which determine the variation in the TM data over water areas. Spectral channels in the near infrared open the possibility of determining the Angstrom exponent better than for the coastal zone color scanner. The suspended matter distribution may then be calculated by the absolute radiance of channel 2 or 3 or the ratio of both. There is no indication of whether separation of chlorophyll is possible. The distribution of suspended matter and sea surface temperature can be observed with the expected fine structure. A good correlation between water depth and suspended matter distribution as found from ship data can now be analyzed for an entire area by the synoptic view of the TM scenes.

  1. Sediment fingerprinting to determine the source of suspended sediment in a southern Piedmont stream.

    Science.gov (United States)

    Mukundan, R; Radcliffe, D E; Ritchie, J C; Risse, L M; McKinley, R A

    2010-01-01

    Thousands of stream miles in the southern Piedmont region are impaired because of high levels of suspended sediment. It is unclear if the source is upland erosion from agricultural sources or bank erosion of historic sediment deposited in the flood plains between 1830 and 1930 when cotton farming was extensive. The objective of this study was to determine the source of high stream suspended sediment concentrations in a typical southern Piedmont watershed using sediment fingerprinting techniques. Twenty-one potential tracers were tested for their ability to discriminate between sources, conservative behavior, and lack of redundancy. Tracer concentrations were determined in potential sediment sources (forests, pastures, row crop fields, stream banks, and unpaved roads and construction sites), and suspended sediment samples collected from the stream and analyzed using mixing models. Results indicated that 137Cs and 15N were the best tracers to discriminate potential sediment sources in this watershed. The delta15N values showed distinct signatures in all the potential suspended sediment sources, and delta15N was a unique tracer to differentiate stream bank soil from upland subsurface soils, such as soil from construction sites, unpaved roads, ditches, and field gullies. Mixing models showed that about 60% of the stream suspended sediment originated from eroding stream banks, 23 to 30% from upland subsoil sources (e.g., construction sites and unpaved roads), and about 10 to 15% from pastures. The results may be applicable to other watersheds in the Piedmont depending on the extent of urbanization occurring in these watersheds. Better understanding of the sources of fine sediment has practical implications on the type of sediment control measures to be adopted. Investment of resources in improving water quality should consider the factors causing stream bank erosion and erosion from unpaved roads and construction sites to water quality impairment.

  2. Design consideration for magnetically suspended flywheel systems

    Science.gov (United States)

    Anand, D.; Kirk, J. A.; Frommer, D. A.

    1985-01-01

    Consideration is given to the design, fabrication, and testing of a magnetically suspended flywheel system for energy storage applications in space. The device is the prototype of a system combining passive suspension of the flywheel plate by samarium cobalt magnets and active control in the radial direction using eight separate magnetic coils. The bearing assembly was machined from a nickel-iron alloy, and the machine parts are all hydrogen annealed. Slots in the magnetic plate allow four independent quadrants for control. The motor/generator component of the system is a brushless dc-permanent magnetic/ironless engine using electronic communication. The system has been tested at over 2500 rpm with satisfactory results. The system characteristics of the flywheel for application in low earth orbit (LEO) are given in a table.

  3. Organics and Suspended Solids Removal from Hospital

    Directory of Open Access Journals (Sweden)

    Fakhri Y. Hmood

    2013-05-01

    Full Text Available The Sequencing Batch Reactor (SBR method is used for treating samples of waste water taken from hospitals in Mosul. Many run periods are used (6-24 hours for             6 months. It is found that the organics and suspended solids removal increase with increasing the period of run, it is in the range ( 96-82 % and ( 100-95 % respectively, while the pH values are nearly neutral (7.05 to 7.5.     BOD5 and SS concentrations of the effluent are within the limits of Iraqi standards,  40:30 mg/l respectively. Hence, SBR method could be used for treating hospitals, small factories and some  residential sectors waste waters.  

  4. Implementation of reversible gates in FPGA structure

    Science.gov (United States)

    Pawłowski, Marek; Szymański, Zbigniew

    2017-08-01

    The paper presents reversible circuits modelling methods in the FPGA structures. Three different methods of reconfigurable reversible gate descriptions are proposed - a direct method of output calculation and two methods of composing the gate from Fredkin and Toffoli gates. The paper shows both 4-bit and 8-bit gates. Application of developed test bench verified the correctness of our designs. The presented descriptions can be used for modelling of complex elements used e.g. in cipher machines based on quantum algorithms.

  5. 3.3 V write-voltage Ir/Ca0.2Sr0.8Bi2Ta2O9/HfO2/Si ferroelectric-gate field-effect transistors with 109 endurance and good retention

    Science.gov (United States)

    Zhang, Wei; Takahashi, Mitsue; Sasaki, Yoshikazu; Kusuhara, Masaki; Sakai, Shigeki

    2017-04-01

    Ir/Ca0.2Sr0.8Bi2Ta2O9 (CSBT)/HfO2/Si ferroelectric-gate field-effect transistors (FeFETs), which were appropriate for low-voltage 3.3 V operations, were developed. The key to the success was the use of N2-dominant gas mixed with a small amount of O2 in a gas flow during the annealing of the FeFETs at 780 °C for CSBT polycrystallization. The Ir gate was newly developed for overcoming the problem of Pt peeling off from the CSBT surface during the novel annealing process. For maximizing the memory windows of the FeFETs, the optimum flow rate of O2 mixed with 1000-sccm-fixed N2 was found to be as low as 0.5 sccm. The novel annealing process suppressed the SiO2 interfacial layer growth to 2.6 nm thickness. The annealing also improved CSBT ferroelectricity. A 109 cycle endurance and a 105 s retention were demonstrated by 3.3 V writing of the FeFETs.

  6. Bill Gates eyes healthcare market.

    Science.gov (United States)

    Dunbar, C

    1995-02-01

    The entrepreneurial spirit is still top in Bill Gates' mind as he look toward healthcare and other growth industries. Microsoft's CEO has not intention of going the way of other large technology companies that became obsolete before they could compete today.

  7. Construction of a fuzzy and all Boolean logic gates based on DNA

    DEFF Research Database (Denmark)

    M. Zadegan, Reza; Jepsen, Mette D E; Hildebrandt, Lasse

    2015-01-01

    DNA locks on one DNA origami box structure enabled fuzzy logical operation that allows biosensing of complex molecular signals. Integrating logic gates with DNA origami systems opens a vast avenue to applications in the fields of nanomedicine for diagnostics and therapeutics.......Logic gates are devices that can perform logical operations by transforming a set of inputs into a predictable single detectable output. The hybridization properties, structure, and function of nucleic acids can be used to make DNA-based logic gates. These devices are important modules in molecular...... computing and biosensing. The ideal logic gate system should provide a wide selection of logical operations, and be integrable in multiple copies into more complex structures. Here we show the successful construction of a small DNA-based logic gate complex that produces fluorescent outputs corresponding...

  8. Volumetric measurement of human red blood cells by MOSFET-based microfluidic gate.

    Science.gov (United States)

    Guo, Jinhong; Ai, Ye; Cheng, Yuanbing; Li, Chang Ming; Kang, Yuejun; Wang, Zhiming

    2015-08-01

    In this paper, we present a MOSFET-based (metal oxide semiconductor field-effect transistor) microfluidic gate to characterize the translocation of red blood cells (RBCs) through a gate. In the microfluidic system, the bias voltage modulated by the particles or biological cells is connected to the gate of MOSFET. The particles or cells can be detected by monitoring the MOSFET drain current instead of DC/AC-gating method across the electronic gate. Polystyrene particles with various standard sizes are utilized to calibrate the proposed device. Furthermore, RBCs from both adults and newborn blood sample are used to characterize the performance of the device in distinguishing the two types of RBCs. As compared to conventional DC/AC current modulation method, the proposed device demonstrates a higher sensitivity and is capable of being a promising platform for bioassay analysis. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. N Channel JFET Based Digital Logic Gate Structure

    Science.gov (United States)

    Krasowski, Michael J (Inventor)

    2013-01-01

    An apparatus is provided that includes a first field effect transistor with a source tied to zero volts and a drain tied to voltage drain drain (Vdd) through a first resistor. The apparatus also includes a first node configured to tie a second resistor to a third resistor and connect to an input of a gate of the first field effect transistor in order for the first field effect transistor to receive a signal. The apparatus also includes a second field effect transistor configured as a unity gain buffer having a drain tied to Vdd and an uncommitted source.

  10. Simulation of suspended sediment transport initialized with satellite derived suspended sediment concentrations

    Science.gov (United States)

    Ramakrishnan, Ratheesh; Rajawat, A. S.

    2012-10-01

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are realized with respect to the sediment size distribution and the bottom bed materials observed in the Gulf. Simulated SSCs are compared with alternate OCM derived SSC. The results are observed to be impetus where the model is able to generate the spatial dynamics of the sediment concentrations. Sediment dynamics like deposition, erosion and dispersion are explained with the simulated tidal currents and OCM derived sediment concentrations. Tidal range is observed as the important physical factor controlling the deposition and resuspension of sediments within the Gulf. From the simulation studies; maximum residual current velocities, tidal fronts and high turbulent zones are found to characterise the islands and shoals within the Gulf, which results in high sediment concentrations in those regions. Remarkable variability in the bathymetry of the Gulf, different bed materials and varying tidal conditions induces several circulation patterns and turbulence creating the unique suspended sediment concentration pattern in the Gulf.

  11. A suspended sediment yield predictive equation for river basins in ...

    African Journals Online (AJOL)

    An empirical equation that can be used for estimating the suspended sediment yields of river drainage basins without sediment data has been established for basins in the sub-tropical forest Southwestern river basin system of Ghana. The power law equation relates mean annual specific suspended sediment yield (t km-2 ...

  12. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud. Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are ...

  13. Energy values of suspended detritus in Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Krishnakumari, L.; Royan, J.P.; Sumitra-Vijayaraghavan

    Energy content of suspended detritus was determined in Andaman Sea waters during April-May 1988. The caloric content of suspended detritus ranged from 987 to 7040 cal. per gram dry wt with an average value of 5530 cal. per gram dry wt. The results...

  14. Evaluation of the suspending properties of Cola acuminata gum on ...

    African Journals Online (AJOL)

    Many natural gums are employed as suspending agents in the formulation of pharmaceutical suspensions. The search to develop locally available natural gum from apparently a waste product as an alternative suspending agent stimulated the interest in this present study. Cola acuminata gum (CAG) extracted from Cola ...

  15. 40 CFR 230.21 - Suspended particulates/turbidity.

    Science.gov (United States)

    2010-07-01

    ... time. These new levels may reduce light penetration and lower the rate of photosynthesis and the... suspended particulates persist. The biological and the chemical content of the suspended material may react with the dissolved oxygen in the water, which can result in oxygen depletion. Toxic metals and organics...

  16. Simulation of suspended sediment transport initialized with satellite ...

    Indian Academy of Sciences (India)

    Suspended sediment transport in the Gulf of Kachchh is simulated utilizing the suspended sediment concentration (SSC) derived from Oceansat OCM imagery, as the initial condition in MIKE-21 Mud Transport model. Optimization of the model mud parameters, like settling velocity and critical shear stress for erosion are ...

  17. Evaluation of the suspending property of grewia gum in ...

    African Journals Online (AJOL)

    The suspending property of grewia gum in sulphadimidine suspension was evaluated. The gum was extracted by maceration, filtration, precipitation and drying techniques. It was used at 0.3 to 1% w/v as a suspending agent for sulphadimidine. Sodiumcarboxymethylcellulose (SCMC) and tragacanth were used as basis for ...

  18. Evaluation of the suspending properties of Adansonia digitata gum ...

    African Journals Online (AJOL)

    Sedimentation volume and rate, rheology, and ease of redispersion were employed as evaluation parameters. The results showed that both hot and cold water extracts of the gum used at 2-3 % w/v produced a better suspending property than 4 % w/v Compound Tragacanth gum. The suspending ability of the gums was in ...

  19. Evaluation of the Suspending Property of Grewia Gum in ...

    African Journals Online (AJOL)

    The suspending property of grewia gum in metronidazole suspension was evaluated. The gum was extracted by maceration, filtration, precipitation and drying techniques. It was used at 0.3 to 1% w/v as a suspending agent for metronidazole. Sodiumcarboxymethylcellulose (SCMC) and tragacanth were used as basis for ...

  20. Hydrodynamics and suspended sediment transport in the Camboriú estuary - Brazil: pre jetty conditions

    OpenAIRE

    Eduardo Siegle; SCHETTINI, Carlos A. F.; KLEIN, Antonio H. F.; Toldo Jr.,Elírio E.

    2009-01-01

    Estuarine hydrodynamics is a key factor in the definition of the filtering capacity of an estuary and results from the interaction of the processes that control the inlet morphodynamics and those that are acting in the mixing of the water in the estuary. The hydrodynamics and suspended sediment transport in the Camboriú estuary were assessed by two field campaigns conducted in 1998 that covered both neap and spring tide conditions. The period measured represents the estuarine hydrodynamics an...

  1. A Simple Transmission Electron Microscopy Method for Fast Thickness Characterization of Suspended Graphene and Graphite Flakes.

    Science.gov (United States)

    Rubino, Stefano; Akhtar, Sultan; Leifer, Klaus

    2016-02-01

    We present a simple, fast method for thickness characterization of suspended graphene/graphite flakes that is based on transmission electron microscopy (TEM). We derive an analytical expression for the intensity of the transmitted electron beam I 0(t), as a function of the specimen thickness t (tgraphene/graphite, the method we propose has the advantage of being simple and fast, requiring only the acquisition of bright-field images.

  2. Positive-bias gate-controlled metal-insulator transition in ultrathin VO2 channels with TiO2 gate dielectrics.

    Science.gov (United States)

    Yajima, Takeaki; Nishimura, Tomonori; Toriumi, Akira

    2015-12-14

    The next generation of electronics is likely to incorporate various functional materials, including those exhibiting ferroelectricity, ferromagnetism and metal-insulator transitions. Metal-insulator transitions can be controlled by electron doping, and so incorporating such a material in transistor channels will enable us to significantly modulate transistor current. However, such gate-controlled metal-insulator transitions have been challenging because of the limited number of electrons accumulated by gate dielectrics, or possible electrochemical reaction in ionic liquid gate. Here we achieve a positive-bias gate-controlled metal-insulator transition near the transition temperature. A significant number of electrons were accumulated via a high-permittivity TiO2 gate dielectric with subnanometre equivalent oxide thickness in the inverse-Schottky-gate geometry. An abrupt transition in the VO2 channel is further exploited, leading to a significant current modulation far beyond the capacitive coupling. This solid-state operation enables us to discuss the electrostatic mechanism as well as the collective nature of gate-controlled metal-insulator transitions, paving the pathway for developing functional field effect transistors.

  3. Renewal of the separate type pool gate

    Energy Technology Data Exchange (ETDEWEB)

    Ohhashi, Nobuyoshi; Izumo, Hironobu; Kameyama, Iwao; Isaka, Masaki; Nakamura, Kiyoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Monden, Yoshihiro; Tazura, Akio

    1999-10-01

    As a part of the modification of JRR-4, the pool gate was renewed. The pool gate is separated into two parts with packing on the both contact faces, and holds the pool water by the pressure caused by a difference of the water levels. The structure and the principle are so simple that treatment of the pool gate is easy. However, it is very difficult to secure the watertight performance of this gate type. Because the uneven and meandering easily occurred in the surface of the packing, in the former pool gate leakage of the pool water from the separate parts of the gate often occurred. Besides, the selection width of rubber material to conform was very small. In renewal of the pool gate, the mock-up experiment of the packing parts was performed. Based on the results, the new pool gate was designed and installed. The new seal structure developed for the new gate was confirmed to have a high watertight performance even under the condition of very low pool water level. And the loads which hung on the packing is decreased in the new developed packing structure. High watertight performance of the new pool gate was confirmed by the leak tests after installation. This report gives the development of the new pool gate with high watertight performance and the construction of it. (author)

  4. Magnetic gates and guides for superconducting vortices

    Science.gov (United States)

    Vlasko-Vlasov, V. K.; Colauto, F.; Buzdin, A. I.; Rosenmann, D.; Benseman, T.; Kwok, W.-K.

    2017-04-01

    We image the motion of superconducting vortices in niobium film covered with a regular array of thin permalloy strips. By altering the magnetization orientation in the strips using a small in-plane magnetic field, we can tune the strength of interactions between vortices and the strip edges, enabling acceleration or retardation of the superconducting vortices in the sample and consequently introducing strong tunable anisotropy into the vortex dynamics. We discuss our observations in terms of the attraction/repulsion between point magnetic charges carried by vortices and lines of magnetic charges at the strip edges and derive analytical formulas for the vortex-magnetic strips coupling. Our approach demonstrates the analogy between the vortex motion regulated by the magnetic strip array and electric carrier flow in gated semiconducting devices. Scaling down the geometrical features of the proposed design may enable controlled manipulation of single vortices, paving the way for Abrikosov vortex microcircuits and memories.

  5. Gate-tunable conducting oxide metasurfaces

    CERN Document Server

    Huang, Yao-Wei; Sokhoyan, Ruzan; Pala, Ragip; Thyagarajan, Krishnan; Han, Seunghoon; Tsai, Din Ping; Atwater, Harry A

    2015-01-01

    Metasurfaces composed of planar arrays of sub-wavelength artificial structures show promise for extraordinary light manipulation; they have yielded novel ultrathin optical components such as flat lenses, wave plates, holographic surfaces and orbital angular momentum manipulation and detection over a broad range of electromagnetic spectrum. However the optical properties of metasurfaces developed to date do not allow for versatile tunability of reflected or transmitted wave amplitude and phase after fabrication, thus limiting their use in a wide range of applications. Here, we experimentally demonstrate a gate-tunable metasurface that enables dynamic electrical control of the phase and amplitude of the plane wave reflected from the metasurface. Tunability arises from field-effect modulation of the complex refractive index of conducting oxide layers incorporated into metasurface antenna elements which are configured in a reflectarray geometry. We measure a phase shift of {\\pi} and ~ 30% change in the reflectanc...

  6. Particle Size Characteristics of Fluvial Suspended Sediment in Proglacial Streams, King George Island, South Shetland Island

    Science.gov (United States)

    Szymczak, Ewa

    2017-12-01

    In this study, the characterization of particle size distribution of suspended sediment that is transported by streams (Ornithologist Creek, Ecology Glacier Creeks, Petrified Forest Creek, Czech Creek, Vanishing Creek, Italian Creek) in the area of the Arctowski Polish Antarctic Station is presented. During the first period of the summer season, the aforementioned streams are supplied by the melting snow fields, while later on, by thawing permafrost. The water samples were collected from the streams at monthly intervals during the Antarctic summer season (January - March) of 2016. The particle size distribution was measured in the laboratory with a LISST-25X laser diffraction particle size analyser. According to Sequoia Scientific Inc., LISST-25X can measure particle sizes (Sauter Mean Diameter) between 2.50 and 500 μm. The results of particle size measurements were analysed in relation to flow velocity (0.18–0.89 m/s), the cross-sectional parameters of the streams, suspended sediment concentration (0.06–167.22 mg/dm3) and the content of particulate organic matter (9.8–84.85%). Overall, the mean particle size ranged from 28.8 to 136 μm. The grain size of well-sorted sediments ranged from 0.076 to 0.57, with the skewness and kurtosis values varying from -0.1 to 0.4, and from 0.67 to 1.3, respectively. Based on the particle size characteristics of suspended sediment, the streams were divided into two groups. For most of the streams, the sediment was very well sorted, while fine sand and very fine sand were dominant fractions displaying symmetric and platykurtic distributions, respectively. Only in two streams, the suspended sediment consisted of silt-size grains, well or moderately well sorted, with coarse-skewness and mostly mesokurtic distribution. The C-M chart suggested that the transportation processes of suspended sediment included the suspended mode only. The grain-size distribution of suspended sediment was mainly influenced by the stream runoff

  7. Biophysics of BK Channel Gating.

    Science.gov (United States)

    Pantazis, A; Olcese, R

    2016-01-01

    BK channels are universal regulators of cell excitability, given their exceptional unitary conductance selective for K(+), joint activation mechanism by membrane depolarization and intracellular [Ca(2+)] elevation, and broad expression pattern. In this chapter, we discuss the structural basis and operational principles of their activation, or gating, by membrane potential and calcium. We also discuss how the two activation mechanisms interact to culminate in channel opening. As members of the voltage-gated potassium channel superfamily, BK channels are discussed in the context of archetypal family members, in terms of similarities that help us understand their function, but also seminal structural and biophysical differences that confer unique functional properties. © 2016 Elsevier Inc. All rights reserved.

  8. Voltage-gated Proton Channels

    Science.gov (United States)

    DeCoursey, Thomas E.

    2014-01-01

    Voltage-gated proton channels, HV1, have vaulted from the realm of the esoteric into the forefront of a central question facing ion channel biophysicists, namely the mechanism by which voltage-dependent gating occurs. This transformation is the result of several factors. Identification of the gene in 2006 revealed that proton channels are homologues of the voltage-sensing domain of most other voltage-gated ion channels. Unique, or at least eccentric, properties of proton channels include dimeric architecture with dual conduction pathways, perfect proton selectivity, a single-channel conductance ~103 smaller than most ion channels, voltage-dependent gating that is strongly modulated by the pH gradient, ΔpH, and potent inhibition by Zn2+ (in many species) but an absence of other potent inhibitors. The recent identification of HV1 in three unicellular marine plankton species has dramatically expanded the phylogenetic family tree. Interest in proton channels in their own right has increased as important physiological roles have been identified in many cells. Proton channels trigger the bioluminescent flash of dinoflagellates, facilitate calcification by coccolithophores, regulate pH-dependent processes in eggs and sperm during fertilization, secrete acid to control the pH of airway fluids, facilitate histamine secretion by basophils, and play a signaling role in facilitating B-cell receptor mediated responses in B lymphocytes. The most elaborate and best-established functions occur in phagocytes, where proton channels optimize the activity of NADPH oxidase, an important producer of reactive oxygen species. Proton efflux mediated by HV1 balances the charge translocated across the membrane by electrons through NADPH oxidase, minimizes changes in cytoplasmic and phagosomal pH, limits osmotic swelling of the phagosome, and provides substrate H+ for the production of H2O2 and HOCl, reactive oxygen species crucial to killing pathogens. PMID:23798303

  9. Analytical modeling of surface accumulation behavior of fully depleted SOI four gate transistors (G4-FETs)

    Science.gov (United States)

    Sayed, Shehrin; Khan, M. Ziaur Rahman

    2013-03-01

    A charge sheet model is proposed to analyze the transistor characteristics of fully depleted SOI four gate field effect transistors (G4-FETs). The model is derived assuming a parabolic potential variation between the junction-gates and by solving 2-D Poisson's equation. The proposed model facilitates the calculation of surface potential and charge densities as a function of all gate biases. Modifying this charge sheet model for non-equilibrium condition, current-voltage and capacitance-voltage characteristics are also analyzed. Different back surface charge conditions are considered for each analysis. The models are compared with 3-D Silvaco/Atlas simulation results which show good agreement.

  10. Reprogrammable Logic Gate and Logic Circuit Based on Multistimuli-Responsive Raspberry-like Micromotors.

    Science.gov (United States)

    Zhang, Lina; Zhang, Hui; Liu, Mei; Dong, Bin

    2016-06-22

    In this paper, we report a polymer-based raspberry-like micromotor. Interestingly, the resulting micromotor exhibits multistimuli-responsive motion behavior. Its on-off-on motion can be regulated by the application of stimuli such as H2O2, near-infrared light, NH3, or their combinations. Because of the versatility in motion control, the current micromotor has great potential in the application field of logic gate and logic circuit. With use of different stimuli as the inputs and the micromotor motion as the output, reprogrammable OR and INHIBIT logic gates or logic circuit consisting of OR, NOT, and AND logic gates can be achieved.

  11. Simulation of dual-gate SOI MOSFET with different dielectric layers

    Science.gov (United States)

    Yadav, Jyoti; Chaudhary, R.; Mukhiya, R.; Sharma, R.; Khanna, V. K.

    2016-04-01

    The paper presents the process design and simulation of silicon-on-insulator (SOI)-based dual-gate metal oxide field-effect transistor (DG-MOSFET) stacked with different dielectric layers on the top of gate oxide. A detailed 2D process simulation of SOI-MOSFETs and its electrical characterization has been done using SILVACO® TCAD tool. A variation in transconductance was observed with different dielectric layers, AlN-gate MOSFET having the highest tranconductance value as compared to other three dielectric layers (SiO2, Si3N4 and Al2O3).

  12. Na+ channel Nav1.9: in search of a gating mechanism.

    Science.gov (United States)

    Delmas, Patrick; Coste, Bertrand

    2003-02-01

    Voltage-gated Na(+) channels play key roles in generating and propagating action potentials. Their gating is believed to rely exclusively on changes in membrane potential. However, recent data from Blum, Kafitz and Konnerth provide direct evidence that the opening of Na(v)1.9, a member of the voltage-gated Na(+) channel family, is mediated by ligand binding rather than by voltage. This is arguably one of the most influential ideas brought to us in the history of the Na(+) channel field.

  13. Large yield production of high mobility freely suspended graphene electronic devices on a polydimethylglutarimide based organic polymer

    NARCIS (Netherlands)

    Tombros, Nikolaos; Veligura, Alina; Junesch, Juliane; Berg, J. Jasper van den; Zomer, Paul J.; Wojtaszek, Magdalena; Vera Marun, Ivan J.; Jonkman, Harry T.; Wees, Bart J. van

    2011-01-01

    The recent observation of a fractional quantum Hall effect in high mobility suspended graphene devices introduced a new direction in graphene physics, the field of electron–electron interaction dynamics. However, the technique used currently for the fabrication of such high mobility devices has

  14. Negative differential transconductance in electrolyte-gated ruthenate

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Muhammad Umair [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Center for Micro and Nano Devices, Department of Physics, COMSATS Institute of Information Technology, Park Road, Shehzad Town 44000, Islamabad (Pakistan); Dhoot, Anoop Singh, E-mail: asd24@cam.ac.uk [Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Wimbush, Stuart C. [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); The MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, P.O. Box 600, Wellington 6140 (New Zealand)

    2015-01-19

    We report on a study of electric field-induced doping of the highly conductive ruthenate SrRuO{sub 3} using an ionic liquid as the gate dielectric in a field-effect transistor configuration. Two distinct carrier transport regimes are identified for increasing positive gate voltage in thin (10 nm) films grown heteroepitaxially on SrTiO{sub 3} substrates. For V{sub g} = 2 V and lower, the sample shows an increased conductivity of up to 13%, as might be expected for electron doping of a metal. At higher V{sub g} = 2.5 V, we observe a large decrease in electrical conductivity of >20% (at 4.2 K) due to the prevalence of strongly blocked conduction pathways.

  15. The Gate Hysteresis in Single Electron Transport Driven by Surface Acoustic Wave (SAW/SET) Devices

    Science.gov (United States)

    Song, Li; Chen, Shuwei

    2017-11-01

    We study the gate hysteresis behavior in single electron transport driven by surface acoustic wave (SAW/SET) devices over a wide temperature range from 1.7 to 200 K. From the temperature dependence, we come to the conclusion that the gate hysteresis in SAW/SET devices arises from a combination of the screening effect of the surface state and the electron tunneling between the moving quantum dot and the impurity quantum dot. In addition, when a perpendicular magnetic field is applied to the sample, the behavior of the gate hysteresis changes substantially. A competition between the magnetic field and the gate voltage on determining the electronic wave function is considered as the reason for the experimental results.

  16. Gate-controllable magneto-optic Kerr effect in layered collinear antiferromagnets

    Science.gov (United States)

    Sivadas, Nikhil; Okamoto, Satoshi; Xiao, Di

    Using symmetry arguments and a tight-binding model, we show that for layered collinear antiferromagnets, magneto-optic effects can be generated and manipulated by controlling crystal symmetries through a gate voltage. This provides a promising route for electric field manipulation of the magneto-optic effects without modifying the underlying magnetic structure. We further demonstrate the gate control of magneto-optic Kerr effect (MOKE) in bilayer MnPSe3 using first-principles calculations. The field-induced inversion symmetry breaking effect leads to gate-controllable MOKE whose direction of rotation can be switched by the reversal of the gate voltage. This work is supported by AFOSR No. FA9550-12-1-0479 and FA9550-14-1-0277 and NSP No. EFRI-1433496.

  17. The universal magnetic tunnel junction logic gates representing 16 binary Boolean logic operations

    Science.gov (United States)

    Lee, Junwoo; Suh, Dong Ik; Park, Wanjun

    2015-05-01

    The novel devices are expected to shift the paradigm of a logic operation by their own nature, replacing the conventional devices. In this study, the nature of our fabricated magnetic tunnel junction (MTJ) that responds to the two external inputs, magnetic field and voltage bias, demonstrated seven basic logic operations. The seven operations were obtained by the electric-field-assisted switching characteristics, where the surface magnetoelectric effect occurs due to a sufficiently thin free layer. The MTJ was transformed as a universal logic gate combined with three supplementary circuits: A multiplexer (MUX), a Wheatstone bridge, and a comparator. With these circuits, the universal logic gates demonstrated 16 binary Boolean logic operations in one logic stage. A possible further approach is parallel computations through a complimentary of MUX and comparator, capable of driving multiple logic gates. A reconfigurable property can also be realized when different logic operations are produced from different level of voltages applying to the same configuration of the logic gate.

  18. Circulation and suspended sediment transport in a coral reef lagoon: the south-west lagoon of New Caledonia.

    Science.gov (United States)

    Ouillon, S; Douillet, P; Lefebvre, J P; Le Gendre, R; Jouon, A; Bonneton, P; Fernandez, J M; Chevillon, C; Magand, O; Lefèvre, J; Le Hir, P; Laganier, R; Dumas, F; Marchesiello, P; Bel Madani, A; Andréfouët, S; Panché, J Y; Fichez, R

    2010-01-01

    The south-west lagoon of New Caledonia is a wide semi-open coral reef lagoon bounded by an intertidal barrier reef and bisected by numerous deep inlets. This paper synthesizes findings from the 2000-2008 French National Program EC2CO-PNEC relative to the circulation and the transport of suspended particles in this lagoon. Numerical model development (hydrodynamic, fine suspended sediment transport, wind-wave, small-scale atmospheric circulation) allowed the determination of circulation patterns in the lagoon and the charting of residence time, the later of which has been recently used in a series of ecological studies. Topical studies based on field measurements permitted the parameterisation of wave set-up induced by the swell breaking on the reef barrier and the validation of a wind-wave model in a fetch-limited environment. The analysis of spatial and temporal variability of suspended matter concentration over short and long time-scales, the measurement of grain size distribution and the density of suspended matter (1.27 kg l(-1)), and the estimation of erodibility of heterogeneous (sand/mud, terrigenous/biogenic) soft bottoms was also conducted. Aggregates were shown to be more abundant near or around reefs and a possible biological influence on this aggregation is discussed. Optical measurements enabled the quantification of suspended matter either in situ (monochromatic measurements) or remotely (surface spectral measurements and satellite observations) and provided indirect calibration and validation of a suspended sediment transport model. The processes that warrant further investigation in order to improve our knowledge of circulation and suspended sediment transport in the New Caledonia lagoon as well as in other coral reef areas are discussed, as are the relevance and reliability of the numerical models for this endeavour. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  19. The role of suspension events in cross-shore and longshore suspended sediment transport in the surf zone

    Science.gov (United States)

    Jaffe, Bruce E.

    2015-01-01

    Suspension of sand in the surf zone is intermittent. Especially striking in a time series of concentration are periods of intense suspension, suspension events, when the water column suspended sediment concentration is an order of magnitude greater than the mean concentration. The prevalence, timing, and contribution of suspension events to cross-shore and longshore suspended sediment transport are explored using field data collected in the inner half of the surf zone during a large storm at Duck, NC. Suspension events are defined as periods when the concentration is above a threshold. Events tended to occur during onshore flow under the wave crest, resulting in an onshore contribution to the suspended sediment transport. Even though large events occurred less than 10 percent of the total time, at some locations onshore transport associated with suspension events was greater than mean-current driven offshore-directed transport during non-event periods, causing the net suspended sediment transport to be onshore. Events and fluctuations in longshore velocity were not correlated. However, events did increase the longshore suspended sediment transport by approximately the amount they increase the mean concentration, which can be up to 35%. Because of the lack of correlation, the longshore suspended sediment transport can be modeled without considering the details of the intensity and time of events as the vertical integration of the product of the time-averaged longshore velocity and an event-augmented time-averaged concentration. However, to accurately model cross-shore suspended sediment transport, the timing and intensity of suspension events must be reproduced.

  20. Frequency response of electrolyte-gated graphene electrodes and transistors

    Science.gov (United States)

    Drieschner, Simon; Guimerà, Anton; Cortadella, Ramon G.; Viana, Damià; Makrygiannis, Evangelos; Blaschke, Benno M.; Vieten, Josua; Garrido, Jose A.

    2017-03-01

    The interface between graphene and aqueous electrolytes is of high importance for applications of graphene in the field of biosensors and bioelectronics. The graphene/electrolyte interface is governed by the low density of states of graphene that limits the capacitance near the Dirac point in graphene and the sheet resistance. While several reports have focused on studying the capacitance of graphene as a function of the gate voltage, the frequency response of graphene electrodes and electrolyte-gated transistors has not been discussed so far. Here, we report on the impedance characterization of single layer graphene electrodes and transistors, showing that due to the relatively high sheet resistance of graphene, the frequency response is governed by the distribution of resistive and capacitive circuit elements along the graphene/electrolyte interface. Based on an analytical solution for the impedance of the distributed circuit elements, we model the graphene/electrolyte interface both for the electrode and the transistor configurations. Using this model, we can extract the relevant material and device parameters such as the voltage-dependent intrinsic sheet and series resistances as well as the interfacial capacitance. The model also provides information about the frequency threshold of electrolyte-gated graphene transistors, above which the device exhibits a non-resistive response, offering an important insight into the suitable frequency range of operation of electrolyte-gated graphene devices.