Transient Characteristics of a Fluidic Device for Circulatory Jet Flow.

Science.gov (United States)

Phan, Hoa Thanh; Dinh, Thien Xuan; Bui, Phong Nhu; Dau, Van Thanh

2018-03-13

In this paper, we report on the design, simulation, and experimental analysis of a miniaturized device that can generate multiple circulated jet flows. The device is actuated by a lead zirconate titanate (PZT) diaphragm. The flows in the device were studied using three-dimensional transient numerical simulation with the programmable open source OpenFOAM and was comparable to the experimental result. Each flow is verified by two hotwires mounted at two positions inside each consisting chamber. The experiment confirmed that the flow was successfully created, and it demonstrated good agreement with the simulation. In addition, a prospective application of the device as an angular rate sensor is also demonstrated. The device is robust, is minimal in size, and can contribute to the development of multi-axis fluidic inertial sensors, fluidic amplifiers, gas mixing, coupling, and analysis.

Development of fluidic device in SIT for Korean Next Generation Reactor I

International Nuclear Information System (INIS)

Cho, Bong Hyun; Lee, Joon; Bae, Yoon Young; Park, Jong Kyun

1999-07-01

The KNGR is to install a Fluidic Device at the bottom of the inner space of the SIT (Safety Injection Tank) to control the flow rate of safety injection coolant from SIT during LBLOCA. During the past two years, a scale model test to obtain the required flow characteristics of the device under the KNGR specific conditions has been performed using the experience and existing facility of AEA Technology (UK) with appropriate modifications. The performance verification test is to be performed this year to obtain optimum characteristics and design data of full size fluidic device. The purpose of the model test was to check the feasibility of developing the device and to produce a generic flow characteristic data. The test was performed in approximately 1/7 scale in terms of flow rate with full height and pressure. This report presents the details of system performance requirements for the device, design procedure for the fluidic device to be used, test facility and test method. The time dependent flow, pressure and Euler number are presented as characteristics curves and the most stable and the most effective flow control characteristic parameters were recommended through the evaluation. A method to predict the size of the fluidic device is presented. And a sizing algorithm, which can be used to conveniently determine the major geometric data of the device for various operating conditions, and a FORTRAN program to produce the prediction of performance curves have been developed. (author). 32 refs., 15 tabs., 47 figs

Nanotube devices based crossbar architecture: toward neuromorphic computing

International Nuclear Information System (INIS)

Zhao, W S; Gamrat, C; Agnus, G; Derycke, V; Filoramo, A; Bourgoin, J-P

2010-01-01

Nanoscale devices such as carbon nanotube and nanowires based transistors, memristors and molecular devices are expected to play an important role in the development of new computing architectures. While their size represents a decisive advantage in terms of integration density, it also raises the critical question of how to efficiently address large numbers of densely integrated nanodevices without the need for complex multi-layer interconnection topologies similar to those used in CMOS technology. Two-terminal programmable devices in crossbar geometry seem particularly attractive, but suffer from severe addressing difficulties due to cross-talk, which implies complex programming procedures. Three-terminal devices can be easily addressed individually, but with limited gain in terms of interconnect integration. We show how optically gated carbon nanotube devices enable efficient individual addressing when arranged in a crossbar geometry with shared gate electrodes. This topology is particularly well suited for parallel programming or learning in the context of neuromorphic computing architectures.

Thermo-fluidic devices and materials inspired from mass and energy transport phenomena in biological system

Institute of Scientific and Technical Information of China (English)

Jian XIAO; Jing LIU

2009-01-01

Mass and energy transport consists of one of the most significant physiological processes in nature, which guarantees many amazing biological phenomena and activ-ities. Borrowing such idea, many state-of-the-art thermo-fluidic devices and materials such as artificial kidneys, carrier erythrocyte, blood substitutes and so on have been successfully invented. Besides, new emerging technologies are still being developed. This paper is dedicated to present-ing a relatively complete review of the typical devices and materials in clinical use inspired by biological mass and energy transport mechanisms. Particularly, these artificial thermo-fluidic devices and materials will be categorized into organ transplantation, drug delivery, nutrient transport, micro operation, and power supply. Potential approaches for innovating conventional technologies were discussed, corresponding biological phenomena and physical mechan-isms were interpreted, future promising mass-and-energy-transport-based bionic devices were suggested, and prospects along this direction were pointed out. It is expected that many artificial devices based on biological mass and energy transport principle will appear to better improve vari-ous fields related to human life in the near future.

Effects on LOCA mass and energy release of the SIT Fluidic device for SKN 3 and 4

International Nuclear Information System (INIS)

Song, Jeung Hyo; Kim, Tae Yoon; Choi, Han Rim; Choi, Chul Jin; Seo, Jong Tae

2003-01-01

A fluidic device is employed for the control of safety injection tank flow during a large break loss of coolant accident in Shin Kori Nuclear power plant Unit 3 and 4. It is installed in the safety injection tank and provides two stages of safety injection tank flow injection, initially high flow injection and then low flow injection after the reactor vessel downcomer annulus full. This allows a more effective use of safety injection tank water inventory during a loss of coolant accident. However, the fluidic device may have an adverse impact on the mass and energy release during the accident. That is, the steam mass and energy release will be increased by a considerable amount because the safety injection tank low flow injection via fluidic device is not credited to condense the steam flows through intact cold legs. The increased mass and energy releases have an impact on the peak pressure and temperature of the containment. This effect of the fluidic device is analyzed on the mass and energy release and the peak pressure and temperature of the containment. The calculation has been done using the CEFLASH-4A, the FLOOD3 with some modifications for the fluidic device and the CONTEMPT-LT code. The results show that the mass and energy release and the peak pressure and temperature were considerably increased when compared with the case without the fluidic device. However, the results satisfy the required design margin

Effects on LOCA mass and energy release of the SIT Fluidic device for SKN 3 and 4

Energy Technology Data Exchange (ETDEWEB)

Song, Jeung Hyo; Kim, Tae Yoon; Choi, Han Rim; Choi, Chul Jin; Seo, Jong Tae [Korea Power Engineering Company, Daejon (Korea, Republic of)

2003-07-01

A fluidic device is employed for the control of safety injection tank flow during a large break loss of coolant accident in Shin Kori Nuclear power plant Unit 3 and 4. It is installed in the safety injection tank and provides two stages of safety injection tank flow injection, initially high flow injection and then low flow injection after the reactor vessel downcomer annulus full. This allows a more effective use of safety injection tank water inventory during a loss of coolant accident. However, the fluidic device may have an adverse impact on the mass and energy release during the accident. That is, the steam mass and energy release will be increased by a considerable amount because the safety injection tank low flow injection via fluidic device is not credited to condense the steam flows through intact cold legs. The increased mass and energy releases have an impact on the peak pressure and temperature of the containment. This effect of the fluidic device is analyzed on the mass and energy release and the peak pressure and temperature of the containment. The calculation has been done using the CEFLASH-4A, the FLOOD3 with some modifications for the fluidic device and the CONTEMPT-LT code. The results show that the mass and energy release and the peak pressure and temperature were considerably increased when compared with the case without the fluidic device. However, the results satisfy the required design margin.

Carbon nanotube-based sensing devices for human Arginase-1 detection

Directory of Open Access Journals (Sweden)

S. Baldo

2016-03-01

Full Text Available A new carbon nanotube-based device for detection of Arginase 1 (ARG-1 was produced. Multi-walled carbon nanotubes (MWCNTs were deposited between electrodes by dielectrophoresis (DEP in an accurate and reproducible way. This deposition method has the advantages of low cost and room temperature conditions and therefore, can be used on different kinds of substrates (silicon, glass, plastics allowing for large scale production of chemical or biological sensors. Scanning electrical microscope (SEM and electrical characterization have been performed on the biosensors before and after protein exposure. The devices were tested in the present work for the detection of ARG-1. They show high sensitivity and reproducibility, and can be easily and suitably modified to detect other proteins. Keywords: Carbon nanotube, Biosensor, Arginase, Dielectrophoresis, Biomarker, Protein

Engineering fluidic delays in paper-based devices using laser direct-writing.

Science.gov (United States)

He, P J W; Katis, I N; Eason, R W; Sones, C L

2015-10-21

We report the use of a new laser-based direct-write technique that allows programmable and timed fluid delivery in channels within a paper substrate which enables implementation of multi-step analytical assays. The technique is based on laser-induced photo-polymerisation, and through adjustment of the laser writing parameters such as the laser power and scan speed we can control the depth and/or the porosity of hydrophobic barriers which, when fabricated in the fluid path, produce controllable fluid delay. We have patterned these flow delaying barriers at pre-defined locations in the fluidic channels using either a continuous wave laser at 405 nm, or a pulsed laser operating at 266 nm. Using this delay patterning protocol we generated flow delays spanning from a few minutes to over half an hour. Since the channels and flow delay barriers can be written via a common laser-writing process, this is a distinct improvement over other methods that require specialist operating environments, or custom-designed equipment. This technique can therefore be used for rapid fabrication of paper-based microfluidic devices that can perform single or multistep analytical assays.

Fabrication of coupled graphene–nanotube quantum devices

International Nuclear Information System (INIS)

Engels, S; Weber, P; Terrés, B; Dauber, J; Volk, C; Wichmann, U; Stampfer, C; Meyer, C; Trellenkamp, S

2013-01-01

We report on the fabrication and characterization of all-carbon hybrid quantum devices based on graphene and single-walled carbon nanotubes. We discuss both carbon nanotube quantum dot devices with graphene charge detectors and nanotube quantum dots with graphene leads. The devices are fabricated by chemical vapor deposition growth of carbon nanotubes and subsequent structuring of mechanically exfoliated graphene. We study the detection of individual charging events in the carbon nanotube quantum dot by a nearby graphene nanoribbon and show that they lead to changes of up to 20% of the conductance maxima in the graphene nanoribbon, acting as a well performing charge detector. Moreover, we discuss an electrically coupled graphene–nanotube junction, which exhibits a tunneling barrier with tunneling rates in the low GHz regime. This allows us to observe Coulomb blockade on a carbon nanotube quantum dot with graphene source and drain leads. (paper)

Nanoparticle/nanotube-based nanoelectronic devices and chemically-directed assembly thereof

Science.gov (United States)

Schmidt, Howard K [Cypress, TX

2011-02-22

According to some embodiments, the present invention provides a nanoelectronic device based on a nanostructure that may include a nanotube with first and second ends, a metallic nanoparticle attached to the first end, and an insulating nanoparticle attached to the second end. The nanoelectronic device may include additional nanostructures so a to form a plurality of nanostructures comprising the first nanostructure and the additional nanostructures. The plurality of nanostructures may arranged in a network comprising a plurality of edges and a plurality of vertices, wherein each edge comprises a nanotube and each vertex comprises at least one insulating nanoparticle and at least one metallic nanoparticle adjacent the insulating nanoparticle. The combination of at least one edge and at least one vertex comprises a diode. The device may be an optical rectenna.

Logic circuits based on individual semiconducting and metallic carbon-nanotube devices

International Nuclear Information System (INIS)

Ryu, Hyeyeon; Kaelblein, Daniel; Ante, Frederik; Zschieschang, Ute; Kern, Klaus; Klauk, Hagen; Weitz, R Thomas; Schmidt, Oliver G

2010-01-01

Nanoscale transistors employing an individual semiconducting carbon nanotube as the channel hold great potential for logic circuits with large integration densities that can be manufactured on glass or plastic substrates. Carbon nanotubes are usually produced as a mixture of semiconducting and metallic nanotubes. Since only semiconducting nanotubes yield transistors, the metallic nanotubes are typically not utilized. However, integrated circuits often require not only transistors, but also resistive load devices. Here we show that many of the metallic carbon nanotubes that are deposited on the substrate along with the semiconducting nanotubes can be conveniently utilized as load resistors with favorable characteristics for the design of integrated circuits. We also demonstrate the fabrication of arrays of transistors and resistors, each based on an individual semiconducting or metallic carbon nanotube, and their integration on glass substrates into logic circuits with switching frequencies of up to 500 kHz using a custom-designed metal interconnect layer.

Diffusion dynamics in micro-fluidic dye lasers

DEFF Research Database (Denmark)

Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Niels Asger

2007-01-01

We have investigated the bleaching dynamics that occur in opto-fluidic dye lasers, where the liquid laser dye in a channel is locally bleached due to optical pumping. Our studies suggest that for micro-fluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone....... By relying on diffusion rather than convection to generate the necessary dye replenishment, our observation potentially allows for a significant simplification of opto-fluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip micro-fluidic pumping...

A study on electromechanical carbon nanotube memory devices

International Nuclear Information System (INIS)

Kang, Jeong Won; Hwang, Ho Jung

2005-01-01

Electromechanical operations of carbon-nanotube (CNT) bridge memory device were investigated by using atomistic simulations based on empirical potentials. The nanotube-bridge memory device was operated by the electrostatic and the van der Waals forces acting on the nanotube-bridge. For the CNT bridge memory device, the van der Waals interactions between the CNT bridge and the oxide were very important. As the distance between the CNT bridge and the oxide decreased and the van der Waals interaction energy increased, the pull-in bias of the CNT-bridge decreased and the nonvolatility of the nanotube-bridge memory device increased, while the pull-out voltages increased. When the materials composed of the oxide film are different, since the van der Waals interactions must be also different, the oxide materials must be carefully selected for the CNT-bridge memory device to work as a nonvolatile memory.

Aligned carbon nanotubes. Physics, concepts, fabrication and devices

Energy Technology Data Exchange (ETDEWEB)

Ren, Zhifeng; Lan, Yucheng [Boston College, Chestnut Hill, MA (United States). Dept. of Physics; Wang, Yang [South China Normal Univ. Guangzhou (China). Inst. for Advanced Materials

2013-07-01

This book gives a survey of the physics and fabrication of carbon nanotubes and their applications in optics, electronics, chemistry and biotechnology. It focuses on the structural characterization of various carbon nanotubes, fabrication of vertically or parallel aligned carbon nanotubes on substrates or in composites, physical properties for their alignment, and applications of aligned carbon nanotubes in field emission, optical antennas, light transmission, solar cells, chemical devices, bio-devices, and many others. Major fabrication methods are illustrated in detail, particularly the most widely used PECVD growth technique on which various device integration schemes are based, followed by applications such as electrical interconnects, nanodiodes, optical antennas, and nanocoax solar cells, whereas current limitations and challenges are also be discussed to lay the foundation for future developments.

Water based fluidic radio frequency metamaterials

Science.gov (United States)

Cai, Xiaobing; Zhao, Shaolin; Hu, Mingjun; Xiao, Junfeng; Zhang, Naibo; Yang, Jun

2017-11-01

Electromagnetic metamaterials offer great flexibility for wave manipulation and enable exceptional functionality design, ranging from negative refraction, anomalous reflection, super-resolution imaging, transformation optics to cloaking, etc. However, demonstration of metamaterials with unprecedented functionalities is still challenging and costly due to the structural complexity or special material properties. Here, we demonstrate for the first time the versatile fluidic radio frequency metamaterials with negative refraction using a water-embedded and metal-coated 3D architecture. Effective medium analysis confirms that metallic frames create an evanescent environment while simultaneously water cylinders produce negative permeability under Mie resonance. The water-metal coupled 3D architectures and the accessory devices for measurement are fabricated by 3D printing with post electroless deposition. Our study also reveals the great potential of fluidic metamaterials and versatility of the 3D printing process in rapid prototyping of customized metamaterials.

Polymer Coatings in 3D-Printed Fluidic Device Channels for Improved Cellular Adherence Prior to Electrical Lysis.

Science.gov (United States)

Gross, Bethany C; Anderson, Kari B; Meisel, Jayda E; McNitt, Megan I; Spence, Dana M

2015-06-16

This paper describes the design and fabrication of a polyjet-based three-dimensional (3D)-printed fluidic device where poly(dimethylsiloxane) (PDMS) or polystyrene (PS) were used to coat the sides of a fluidic channel within the device to promote adhesion of an immobilized cell layer. The device was designed using computer-aided design software and converted into an .STL file prior to printing. The rigid, transparent material used in the printing process provides an optically transparent path to visualize endothelial cell adherence and supports integration of removable electrodes for electrical cell lysis in a specified portion of the channel (1 mm width × 0.8 mm height × 2 mm length). Through manipulation of channel geometry, a low-voltage power source (500 V max) was used to selectively lyse adhered endothelial cells in a tapered region of the channel. Cell viability was maintained on the device over a 5 day period (98% viable), though cell coverage decreased after day 4 with static media delivery. Optimal lysis potentials were obtained for the two fabricated device geometries, and selective cell clearance was achieved with cell lysis efficiencies of 94 and 96%. The bottleneck of unknown surface properties from proprietary resin use in fabricating 3D-printed materials is overcome through techniques to incorporate PDMS and PS.

Nanotube resonator devices

Science.gov (United States)

Jensen, Kenneth J; Zettl, Alexander K; Weldon, Jeffrey A

2014-05-06

A fully-functional radio receiver fabricated from a single nanotube is being disclosed. Simultaneously, a single nanotube can perform the functions of all major components of a radio: antenna, tunable band-pass filter, amplifier, and demodulator. A DC voltage source, as supplied by a battery, can power the radio. Using carrier waves in the commercially relevant 40-400 MHz range and both frequency and amplitude modulation techniques, successful music and voice reception has been demonstrated. Also disclosed are a radio transmitter and a mass sensor using a nanotube resonator device.

Fluidic Elements based on Coanda Effect

Directory of Open Access Journals (Sweden)

Constantin OLIVOTTO

2010-12-01

Full Text Available This paper contains first some definitions and classifications regarding the fluidic elements. Thegeneral current status is presented, nominating the main specific elements based on the Coanda effect developedspecially in Romania. In particularly the development of an original bistable element using industrial compressedair at industrial pressure supply is presented. The function of this element is based on the controlled attachmentof the main jet at a curved wall through the Coanda effect. The methods used for particular calculation andexperiments are nominated. The main application of these elements was to develop a specific execution element:a fluidic step–by-step motor based on the Coanda effect.

Rapid prototyping of nanotube-based devices using topology-optimized microgrippers

DEFF Research Database (Denmark)

Sardan, Özlem; Eichhorn, Volkmar; Petersen, D.H.

2008-01-01

Nanorobotic handling of carbon nanotubes (CNTs) using microgrippers is one of the most promising approaches for the rapid characterization of the CNTs and also for the assembly of prototypic nanotube-based devices. In this paper, we present pick-and-place nanomanipulation of multi-walled CNTs...... in a rapid and a reproducible manner. We placed CNTs on copper TEM grids for structural analysis and on AFM probes for the assembly of AFM super-tips. We used electrothermally actuated polysilicon microgrippers designed using topology optimization in the experiments. The microgrippers are able to open...... with an amorphous carbon layer, which is locally removed at the contact points with the microgripper. The assembled AFM super-tips are used for AFM measurements of microstructures with high aspect ratios....

Experimental Nanofluidics in an individual Nanotube

Science.gov (United States)

Siria, Alessandro; Poncharal, Philippe; Biance, Anne Laure; Fulcrand, Remy; Purcell, Stephen; Bocquet, Lyderic

2012-11-01

Building new devices that benefit from the strange transport behavior of fluids at nanoscales is an open and worthy challenge that may lead to new scientific and technological paradigms. We present here a new class of nanofluidic device, made of individual Boron-Nitride (BN) nanotube inserted in a pierced membrane and connecting two macroscopic reservoirs. We explore fluidic transport inside a single BN nanotube under electric fields, pressure drops, chemical gradients, and combinations of these. We show that in this transmembrane geometry, the pressure-driven streaming current is voltage gated, with an apparent electro-osmotic zeta potential raising up to one volt. Further, we measured the current induced by ion concentration gradients and show its dependency on the surface charge.

Electrical device fabrication from nanotube formations

Science.gov (United States)

Nicholas, Nolan Walker; Kittrell, W. Carter; Kim, Myung Jong; Schmidt, Howard K.

2013-03-12

A method for forming nanotube electrical devices, arrays of nanotube electrical devices, and device structures and arrays of device structures formed by the methods. Various methods of the present invention allow creation of semiconducting and/or conducting devices from readily grown SWNT carpets rather than requiring the preparation of a patterned growth channel and takes advantage of the self-controlling nature of these carpet heights to ensure a known and controlled channel length for reliable electronic properties as compared to the prior methods.

Functional materials based on carbon nanotubes: Carbon nanotube actuators and noncovalent carbon nanotube modification

Science.gov (United States)

Fifield, Leonard S.

Carbon nanotubes have attractive inherent properties that encourage the development of new functional materials and devices based on them. The use of single wall carbon nanotubes as electromechanical actuators takes advantage of the high mechanical strength, surface area and electrical conductivity intrinsic to these molecules. The work presented here investigates the mechanisms that have been discovered for actuation of carbon nanotube paper: electrostatic, quantum chemical charge injection, pneumatic and viscoelastic. A home-built apparatus for the measurement of actuation strain is developed and utilized in the investigation. An optical fiber switch, the first demonstrated macro-scale device based on the actuation of carbon nanotubes, is described and its performance evaluated. Also presented here is a new general process designed to modify the surface of carbon nanotubes in a non-covalent, non-destructive way. This method can be used to impart new functionalities to carbon nanotube samples for a variety of applications including sensing, solar energy conversion and chemical separation. The process described involves the achievement of large degrees of graphitic surface coverage with polycyclic aromatic hydrocarbons through the use of supercritical fluids. These molecules are bifunctional agents that anchor a desired chemical group to the aromatic surface of the carbon nanotubes without adversely disrupting the conjugated backbone that gives rise the attractive electronic and physical properties of the nanotubes. Both the nanotube functionalization work and the actuator work presented here emphasize how an understanding and control of nanoscale structure and phenomena can be of vital importance in achieving desired performance for active materials. Opportunities for new devices with improved function over current state-of-the-art can be envisioned and anticipated based on this understanding and control.

Hot spot dynamics in carbon nanotube array devices.

Science.gov (United States)

Engel, Michael; Steiner, Mathias; Seo, Jung-Woo T; Hersam, Mark C; Avouris, Phaedon

2015-03-11

We report on the dynamics of spatial temperature distributions in aligned semiconducting carbon nanotube array devices with submicrometer channel lengths. By using high-resolution optical microscopy in combination with electrical transport measurements, we observe under steady state bias conditions the emergence of time-variable, local temperature maxima with dimensions below 300 nm, and temperatures above 400 K. On the basis of time domain cross-correlation analysis, we investigate how the intensity fluctuations of the thermal radiation patterns are correlated with the overall device current. The analysis reveals the interdependence of electrical current fluctuations and time-variable hot spot formation that limits the overall device performance and, ultimately, may cause device degradation. The findings have implications for the future development of carbon nanotube-based technologies.

Effect of single walled carbon nanotubes on the threshold voltage of dye based photovoltaic devices

International Nuclear Information System (INIS)

Chakraborty, S.; Manik, N.B.

2016-01-01

Carbon nanotubes are being widely used in organic photovoltaic (OPV) devices as their usage has been reported to enhance the device efficiency along with other related parameters. In this work we have studied the energy (E_c) effect of single walled carbon nanotubes (SWCNT) on the threshold voltage (V_t_h) and also on the trap states of dye based photovoltaic devices. SWCNT is added in a series of dyes such as Rose Bengal (RB), Methyl Red (MR), Malachite Green (MG) and Crystal Violet (CV). By analysing the steady state dark current–voltage (I–V) characteristics V_t_h and E_c is estimated for the different devices with and without addition of SWCNT. It is observed that on an average for all the dyes V_t_h is reduced by about 30% in presence of SWCNT. The trap energy E_c also reduces in case of all the dyes. The relation between V_t_h, E_c and total trap density is discussed. From the photovoltaic measurements it is seen that the different photovoltaic parameters change with addition of SWCNT to the dye based devices. Both the short circuit current density and fill factor are found to increase for all the dye based devices in presence of SWCNT.

Encapsulation of Fluidic Tubing and Microelectrodes in Microfluidic Devices: Integrating Off-Chip Process and Coupling Conventional Capillary Electrophoresis with Electrochemical Detection.

Science.gov (United States)

Becirovic, Vedada; Doonan, Steven R; Martin, R Scott

2013-08-21

In this paper, an approach to fabricate epoxy or polystyrene microdevices with encapsulated tubing and electrodes is described. Key features of this approach include a fixed alignment between the fluidic tubing and electrodes, the ability to polish the device when desired, and the low dead volume nature of the fluidic interconnects. It is shown that a variety of tubing can be encapsulated with this approach, including fused silica capillary, polyetheretherketone (PEEK), and perfluoroalkoxy (PFA), with the resulting tubing/microchip interface not leading to significant band broadening or plug dilution. The applicability of the devices with embedded tubing is demonstrated by integrating several off-chip analytical methods to the microchip. This includes droplet transfer, droplet desegmentation, and microchip-based flow injection analysis. Off-chip generated droplets can be transferred to the microchip with minimal coalescence, while flow injection studies showed improved peak shape and sensitivity when compared to the use of fluidic interconnects with an appreciable dead volume. Importantly, it is shown that this low dead volume approach can be extended to also enable the integration of conventional capillary electrophoresis (CE) with electrochemical detection. This is accomplished by embedding fused silica capillary along with palladium (for grounding the electrophoresis voltage) and platinum (for detection) electrodes. With this approach, up to 128,000 theoretical plates for dopamine was possible. In all cases, the tubing and electrodes are housed in a rigid base; this results in extremely robust devices that will be of interest to researchers wanting to develop microchips for use by non-experts.

Measurement of microchannel fluidic resistance with a standard voltage meter

International Nuclear Information System (INIS)

Godwin, Leah A.; Deal, Kennon S.; Hoepfner, Lauren D.; Jackson, Louis A.; Easley, Christopher J.

2013-01-01

Highlights: ► Standard voltage meter used to measure fluidic resistance. ► Manual measurement takes a few seconds, akin to electrical resistance measurements. ► Measurement error is reduced compared to other approaches. ► Amenable to dynamic measurement of fluidic resistance. - Abstract: A simplified method for measuring the fluidic resistance (R fluidic ) of microfluidic channels is presented, in which the electrical resistance (R elec ) of a channel filled with a conductivity standard solution can be measured and directly correlated to R fluidic using a simple equation. Although a slight correction factor could be applied in this system to improve accuracy, results showed that a standard voltage meter could be used without calibration to determine R fluidic to within 12% error. Results accurate to within 2% were obtained when a geometric correction factor was applied using these particular channels. When compared to standard flow rate measurements, such as meniscus tracking in outlet tubing, this approach provided a more straightforward alternative and resulted in lower measurement error. The method was validated using 9 different fluidic resistance values (from ∼40 to 600 kPa s mm −3 ) and over 30 separately fabricated microfluidic devices. Furthermore, since the method is analogous to resistance measurements with a voltage meter in electrical circuits, dynamic R fluidic measurements were possible in more complex microfluidic designs. Microchannel R elec was shown to dynamically mimic pressure waveforms applied to a membrane in a variable microfluidic resistor. The variable resistor was then used to dynamically control aqueous-in-oil droplet sizes and spacing, providing a unique and convenient control system for droplet-generating devices. This conductivity-based method for fluidic resistance measurement is thus a useful tool for static or real-time characterization of microfluidic systems.

Point of care with micro fluidic paper based device integrated with nano zeolite-graphene oxide nanoflakes for electrochemical sensing of ketamine.

Science.gov (United States)

Narang, Jagriti; Malhotra, Nitesh; Singhal, Chaitali; Mathur, Ashish; Chakraborty, Dhritiman; Anil, Anusree; Ingle, Aviraj; Pundir, Chandra S

2017-02-15

The present study was aimed to develop an ultrasensitive technique for electroanalysis of ketamine; a date rape drug. It involved the fabrication of nano-hybrid based electrochemical micro fluidic paper-based analytical device (EμPADs) for electrochemical sensing of ketamine. A paper chip was developed using zeolites nanoflakes and graphene-oxide nanocrystals (Zeo-GO). EμPAD offers many advantages such as facile approach, economical and potential for commercialization. Nanocrystal modified EμPAD showed wide linear range 0.001-5nM/mL and a very low detection limit of 0.001nM/mL. The developed sensor was tested in real time samples like alcoholic and non-alcoholic drinks and found good correlation (99%). The hyphenation of EμPAD integrated with nanocrystalline Zeo-GO for detection of ketamine has immense prospective for field-testing platforms. An extensive development could be made for industrial translation of this fabricated device. Copyright © 2016 Elsevier B.V. All rights reserved.

Measurement of microchannel fluidic resistance with a standard voltage meter.

Science.gov (United States)

Godwin, Leah A; Deal, Kennon S; Hoepfner, Lauren D; Jackson, Louis A; Easley, Christopher J

2013-01-03

A simplified method for measuring the fluidic resistance (R(fluidic)) of microfluidic channels is presented, in which the electrical resistance (R(elec)) of a channel filled with a conductivity standard solution can be measured and directly correlated to R(fluidic) using a simple equation. Although a slight correction factor could be applied in this system to improve accuracy, results showed that a standard voltage meter could be used without calibration to determine R(fluidic) to within 12% error. Results accurate to within 2% were obtained when a geometric correction factor was applied using these particular channels. When compared to standard flow rate measurements, such as meniscus tracking in outlet tubing, this approach provided a more straightforward alternative and resulted in lower measurement error. The method was validated using 9 different fluidic resistance values (from ∼40 to 600kPa smm(-3)) and over 30 separately fabricated microfluidic devices. Furthermore, since the method is analogous to resistance measurements with a voltage meter in electrical circuits, dynamic R(fluidic) measurements were possible in more complex microfluidic designs. Microchannel R(elec) was shown to dynamically mimic pressure waveforms applied to a membrane in a variable microfluidic resistor. The variable resistor was then used to dynamically control aqueous-in-oil droplet sizes and spacing, providing a unique and convenient control system for droplet-generating devices. This conductivity-based method for fluidic resistance measurement is thus a useful tool for static or real-time characterization of microfluidic systems. Copyright © 2012 Elsevier B.V. All rights reserved.

Computational modelling of a non-viscous fluid flow in a multi-walled carbon nanotube modelled as a Timoshenko beam

International Nuclear Information System (INIS)

Khosravian, N; Rafii-Tabar, H

2008-01-01

In the design of nanotube-based fluidic devices, a critical issue is the effect of the induced vibrations in the nanotube arising from the fluid flow, since these vibrations can promote structural instabilities, such as buckling transitions. It is known that the induced resonant frequencies depend on the fluid flow velocity in a significant manner. We have studied, for the first time, the flow of a non-viscous fluid in stubby multi-walled carbon nanotubes, using the Timoshenko classical beam theory to model the nanotubes as a continuum structure. We have obtained the variations of the resonant frequencies with the fluid flow velocity under several experimentally interesting boundary conditions and aspect ratios of the nanotube. The main finding from our work is that, compared to an Euler-Bernoulli classical beam model of a nanotube, the Timoshenko beam predicts the loss of stability at lower fluid flow velocities

Computational modelling of a non-viscous fluid flow in a multi-walled carbon nanotube modelled as a Timoshenko beam

Energy Technology Data Exchange (ETDEWEB)

Khosravian, N; Rafii-Tabar, H [Computational Physical Sciences Research Laboratory, Department of Nano-Science, Institute for Research in Fundamental Sciences (IPM), PO Box 19395-5531, Tehran (Iran, Islamic Republic of)], E-mail: rafii-tabar@nano.ipm.ac.ir

2008-07-09

In the design of nanotube-based fluidic devices, a critical issue is the effect of the induced vibrations in the nanotube arising from the fluid flow, since these vibrations can promote structural instabilities, such as buckling transitions. It is known that the induced resonant frequencies depend on the fluid flow velocity in a significant manner. We have studied, for the first time, the flow of a non-viscous fluid in stubby multi-walled carbon nanotubes, using the Timoshenko classical beam theory to model the nanotubes as a continuum structure. We have obtained the variations of the resonant frequencies with the fluid flow velocity under several experimentally interesting boundary conditions and aspect ratios of the nanotube. The main finding from our work is that, compared to an Euler-Bernoulli classical beam model of a nanotube, the Timoshenko beam predicts the loss of stability at lower fluid flow velocities.

Integration of fluidic jet actuators in composite structures

Science.gov (United States)

Schueller, Martin; Lipowski, Mathias; Schirmer, Eckart; Walther, Marco; Otto, Thomas; Geßner, Thomas; Kroll, Lothar

2015-04-01

Fluidic Actuated Flow Control (FAFC) has been introduced as a technology that influences the boundary layer by actively blowing air through slots or holes in the aircraft skin or wind turbine rotor blade. Modern wing structures are or will be manufactured using composite materials. In these state of the art systems, AFC actuators are integrated in a hybrid approach. The new idea is to directly integrate the active fluidic elements (such as SJAs and PJAs) and their components in the structure of the airfoil. Consequently, the integration of such fluidic devices must fit the manufacturing process and the material properties of the composite structure. The challenge is to integrate temperature-sensitive active elements and to realize fluidic cavities at the same time. The transducer elements will be provided for the manufacturing steps using roll-to-roll processes. The fluidic parts of the actuators will be manufactured using the MuCell® process that provides on the one hand the defined reproduction of the fluidic structures and, on the other hand, a high light weight index. Based on the first design concept, a demonstrator was developed in order to proof the design approach. The output velocity on the exit was measured using a hot-wire anemometer.

Chemical detection with nano/bio hybrid devices based on carbon nanotubes and graphene

Science.gov (United States)

Lerner, Mitchell Bryant

Carbon nanotube field-effect transistors (NT-FETs) and graphene field effect transistors (GFETs) provide a unique transduction platform for chemical and biomolecular detection. The work presented in this thesis describes the fabrication, characterization, and investigation of operational mechanisms of carbon-based biosensors. In the first set of experiments, we used carbon nanotubes as fast, all-electronic readout elements in novel vapor sensors, suitable for applications in environmental monitoring and medicine. Molecules bound to the hybrid alter the electrical properties of the NT-FET via several mechanisms, allowing direct detection as a change in the transistor conduction properties. Vapor sensors suitable for more complex system architectures characteristic of mammalian olfaction were demonstrated using NT-FETs functionalized with mouse olfactory receptor (mOR) proteins or single stranded DNA (ssDNA). Substitution of graphene as the channel material enabled production of hundreds of electronically similar devices with high yield. Etching large scale chemical vapor deposition (CVD)-grown graphene into small channels is itself a challenging problem, and we have developed novel fabrication methods to this end without sacrificing the inherent electrical quality that makes graphene such an attractive material. Large arrays of such devices have potential utility for understanding the physics of ligand-receptor interactions and contributing to the development of a new generation of devices for electronic olfaction. Tailored and specific detection was accomplished by chemically functionalizing the NT-FET or GFET with biomolecules, such as proteins or small molecules, to create a hybrid nanostructures. Targets for detection were widely varied, indicating the utility of these techniques, such as 1) live Salmonella cells in nutrient broth, 2) a biomarker protein indicative of prostate cancer, 3) antigen protein from the bacterium that causes Lyme disease, and 4) glucose

A microfluidic device for simultaneous measurement of viscosity and flow rate of blood in a complex fluidic network.

Science.gov (United States)

Jun Kang, Yang; Yeom, Eunseop; Lee, Sang-Joon

2013-01-01

Blood viscosity has been considered as one of important biophysical parameters for effectively monitoring variations in physiological and pathological conditions of circulatory disorders. Standard previous methods make it difficult to evaluate variations of blood viscosity under cardiopulmonary bypass procedures or hemodialysis. In this study, we proposed a unique microfluidic device for simultaneously measuring viscosity and flow rate of whole blood circulating in a complex fluidic network including a rat, a reservoir, a pinch valve, and a peristaltic pump. To demonstrate the proposed method, a twin-shaped microfluidic device, which is composed of two half-circular chambers, two side channels with multiple indicating channels, and one bridge channel, was carefully designed. Based on the microfluidic device, three sequential flow controls were applied to identify viscosity and flow rate of blood, with label-free and sensorless detection. The half-circular chamber was employed to achieve mechanical membrane compliance for flow stabilization in the microfluidic device. To quantify the effect of flow stabilization on flow fluctuations, a formula of pulsation index (PI) was analytically derived using a discrete fluidic circuit model. Using the PI formula, the time constant contributed by the half-circular chamber is estimated to be 8 s. Furthermore, flow fluctuations resulting from the peristaltic pumps are completely removed, especially under periodic flow conditions within short periods (T viscosity with respect to varying flow rate conditions [(a) known blood flow rate via a syringe pump, (b) unknown blood flow rate via a peristaltic pump]. As a result, the flow rate and viscosity of blood can be simultaneously measured with satisfactory accuracy. In addition, the proposed method was successfully applied to identify the viscosity of rat blood, which circulates in a complex fluidic network. These observations confirm that the proposed method can be used for

Computational modelling of the flow of viscous fluids in carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Khosravian, N [Computational Physical Sciences Research Laboratory, Department of Nano-Science, Institute for Research in Fundamental Sciences (IPM), PO Box 19395-5531, Tehran (Iran, Islamic Republic of); Rafii-Tabar, H [Computational Physical Sciences Research Laboratory, Department of Nano-Science, Institute for Research in Fundamental Sciences (IPM), PO Box 19395-5531, Tehran (Iran, Islamic Republic of)

2007-11-21

Carbon nanotubes will have extensive application in all areas of nano-technology, and in particular in the field of nano-fluidics, wherein they can be used for molecular separation, nano-scale filtering and as nano-pipes for conveying fluids. In the field of nano-medicine, nanotubes can be functionalized with various types of receptors to act as bio-sensors for the detection and elimination of cancer cells, or be used as bypasses and even neural connections. Modelling fluid flow inside nanotubes is a very challenging problem, since there is a complex interplay between the motion of the fluid and the stability of the walls. A critical issue in the design of nano-fluidic devices is the induced vibration of the walls, due to the fluid flow, which can promote structural instability. It has been established that the resonant frequencies depend on the flow velocity. We have studied, for the first time, the flow of viscous fluids through multi-walled carbon nanotubes, using the Euler-Bernoulli classical beam theory to model the nanotube as a continuum structure. Our aim has been to compute the effect of the fluid flow on the structural stability of the nanotubes, without having to consider the details of the fluid-walls interaction. The variations of the resonant frequencies with the flow velocity are obtained for both unembedded nanotubes, and when they are embedded in an elastic medium. It is found that a nanotube conveying a viscous fluid is more stable against vibration-induced buckling than a nanotube conveying a non-viscous fluid, and that the aspect ratio plays the same role in both cases.

Computational modelling of the flow of viscous fluids in carbon nanotubes

International Nuclear Information System (INIS)

Khosravian, N; Rafii-Tabar, H

2007-01-01

Carbon nanotubes will have extensive application in all areas of nano-technology, and in particular in the field of nano-fluidics, wherein they can be used for molecular separation, nano-scale filtering and as nano-pipes for conveying fluids. In the field of nano-medicine, nanotubes can be functionalized with various types of receptors to act as bio-sensors for the detection and elimination of cancer cells, or be used as bypasses and even neural connections. Modelling fluid flow inside nanotubes is a very challenging problem, since there is a complex interplay between the motion of the fluid and the stability of the walls. A critical issue in the design of nano-fluidic devices is the induced vibration of the walls, due to the fluid flow, which can promote structural instability. It has been established that the resonant frequencies depend on the flow velocity. We have studied, for the first time, the flow of viscous fluids through multi-walled carbon nanotubes, using the Euler-Bernoulli classical beam theory to model the nanotube as a continuum structure. Our aim has been to compute the effect of the fluid flow on the structural stability of the nanotubes, without having to consider the details of the fluid-walls interaction. The variations of the resonant frequencies with the flow velocity are obtained for both unembedded nanotubes, and when they are embedded in an elastic medium. It is found that a nanotube conveying a viscous fluid is more stable against vibration-induced buckling than a nanotube conveying a non-viscous fluid, and that the aspect ratio plays the same role in both cases

Local gate control in carbon nanotube quantum devices

Science.gov (United States)

Biercuk, Michael Jordan

This thesis presents transport measurements of carbon nanotube electronic devices operated in the quantum regime. Nanotubes are contacted by source and drain electrodes, and multiple lithographically-patterned electrostatic gates are aligned to each device. Transport measurements of device conductance or current as a function of local gate voltages reveal that local gates couple primarily to the proximal section of the nanotube, hence providing spatially localized control over carrier density along the nanotube length. Further, using several different techniques we are able to produce local depletion regions along the length of a tube. This phenomenon is explored in detail for different contact metals to the nanotube. We utilize local gating techniques to study multiple quantum dots in carbon nanotubes produced both by naturally occurring defects, and by the controlled application of voltages to depletion gates. We study double quantum dots in detail, where transport measurements reveal honeycomb charge stability diagrams. We extract values of energy-level spacings, capacitances, and interaction energies for this system, and demonstrate independent control over all relevant tunneling rates. We report rf-reflectometry measurements of gate-defined carbon nanotube quantum dots with integrated charge sensors. Aluminum rf-SETs are electrostatically coupled to carbon nanotube devices and detect single electron charging phenomena in the Coulomb blockade regime. Simultaneous correlated measurements of single electron charging are made using reflected rf power from the nanotube itself and from the rf-SET on microsecond time scales. We map charge stability diagrams for the nanotube quantum dot via charge sensing, observing Coulomb charging diamonds beyond the first order. Conductance measurements of carbon nanotubes containing gated local depletion regions exhibit plateaus as a function of gate voltage, spaced by approximately 1e2/h, the quantum of conductance for a single

Fluidic interconnections for microfluidic systems: A new integrated fluidic interconnection allowing plug 'n' play functionality

DEFF Research Database (Denmark)

Perozziello, Gerardo; Bundgaard, Frederik; Geschke, Oliver

2008-01-01

A crucial challenge in packaging of microsystems is microfluidic interconnections. These have to seal the ports of the system, and have to provide the appropriate interface to other devices or the external environment. Integrated fluidic interconnections appear to be a good solution for interconn...... external metal ferrules and the system. Theoretical calculations are made to dimension and model the integrated fluidic interconnection. Leakage tests are performed on the interconnections, in order to experimentally confirm the model, and detect its limits....

Fluidic sampling

International Nuclear Information System (INIS)

Houck, E.D.

1992-01-01

This paper covers the development of the fluidic sampler and its testing in a fluidic transfer system. The major findings of this paper are as follows. Fluidic jet samples can dependably produce unbiased samples of acceptable volume. The fluidic transfer system with a fluidic sampler in-line will transfer water to a net lift of 37.2--39.9 feet at an average ratio of 0.02--0.05 gpm (77--192 cc/min). The fluidic sample system circulation rate compares very favorably with the normal 0.016--0.026 gpm (60--100 cc/min) circulation rate that is commonly produced for this lift and solution with the jet-assisted airlift sample system that is normally used at ICPP. The volume of the sample taken with a fluidic sampler is dependant on the motive pressure to the fluidic sampler, the sample bottle size and on the fluidic sampler jet characteristics. The fluidic sampler should be supplied with fluid having the motive pressure of the 140--150 percent of the peak vacuum producing motive pressure for the jet in the sampler. Fluidic transfer systems should be operated by emptying a full pumping chamber to nearly empty or empty during the pumping cycle, this maximizes the solution transfer rate

Detection of multiple tumor markers using ultra-long carbon nanotube devices

Science.gov (United States)

So, Hye-Mi; Park, Dong-Won; Kim, Beom Soo; Kong, Ki-Jeong; Buh, Gyoung-Ho; Chang, Hyunju; Lee, Jeong-O.; Kong, Jing

2008-03-01

For the simultaneous detection of multiple tumor markers, we have fabricated ultra-long carbon nanotube sensors that can detect carcinoembryonic antigen (CEA) and prostate specific antigen (PSA), simultaneously. Ultra-long carbon nanotubes, several millimeters long, were grown by ethanol CVD, and fabricated as FET sensors by using conventional photolithography. To functionalize each segment of a single ultra-long nanotube device with multiple-tumor markers, we first functionalize the entire device with CDI-Tween 20 linking molecules, and then immobilized CEA and PSA antibodies using the microfluidic channel. The electrical conductance from CEA-antibody functionalized and PSA-antibody functionalized segment of a ultra-long carbon nanotube device was monitored simultaneously with Ag/AgCl reference electrode as a liquid gate. We will discuss the advantages of long-nanotube device in detail.

Carbon Based Transistors and Nanoelectronic Devices

Science.gov (United States)

Rouhi, Nima

Carbon based materials (carbon nanotube and graphene) has been extensively researched during the past decade as one of the promising materials to be used in high performance device technology. In long term it is thought that they may replace digital and/or analog electronic devices, due to their size, near-ballistic transport, and high stability. However, a more realistic point of insertion into market may be the printed nanoelectronic circuits and sensors. These applications include printed circuits for flexible electronics and displays, large-scale bendable electrical contacts, bio-membranes and bio sensors, RFID tags, etc. In order to obtain high performance thin film transistors (as the basic building block of electronic circuits) one should be able to manufacture dense arrays of all semiconducting nanotubes. Besides, graphene synthesize and transfer technology is in its infancy and there is plenty of room to improve the current techniques. To realize the performance of nanotube and graphene films in such systems, we need to economically fabricate large-scale devices based on these materials. Following that the performance control over such devices should also be considered for future design variations for broad range of applications. Here we have first investigated carbon nanotube ink as the base material for our devices. The primary ink used consisted of both metallic and semiconducting nanotubes which resulted in networks suitable for moderate-resistivity electrical connections (such as interconnects) and rfmatching circuits. Next, purified all-semiconducting nanotube ink was used to fabricate waferscale, high performance (high mobility, and high on/off ratio) thin film transistors for printed electronic applications. The parameters affecting device performance were studied in detail to establish a roadmap for the future of purified nanotube ink printed thin film transistors. The trade of between mobility and on/off ratio of such devices was studied and the

Applied Physics of Carbon Nanotubes Fundamentals of Theory, Optics and Transport Devices

CERN Document Server

Rotkin, Slava V

2005-01-01

The book describes the state-of-the-art in fundamental, applied and device physics of nanotubes, including fabrication, manipulation and characterization for device applications; optics of nanotubes; transport and electromechanical devices and fundamentals of theory for applications. This information is critical to the field of nanoscience since nanotubes have the potential to become a very significant electronic material for decades to come. The book will benefit all all readers interested in the application of nanotubes, either in their theoretical foundations or in newly developed characterization tools that may enable practical device fabrication.

Fluidic control of reactor flow—Pressure drop matching

Czech Academy of Sciences Publication Activity Database

Tesař, Václav

2009-01-01

Roč. 87, č. 6A (2009), s. 817-832 ISSN 0263-8762 R&D Projects: GA AV ČR IAA200760705; GA ČR GA101/07/1499 Institutional research plan: CEZ:AV0Z20760514 Keywords : fluidics * matching of fluidic devices * dissipance Subject RIV: BK - Fluid Dynamics Impact factor: 1.223, year: 2009 http://www.sciencedirect.com/science

Automated micro fluidic system for PCR applications in the monitoring of drinking water quality

International Nuclear Information System (INIS)

Soria Soria, E.; Yanez Amoros, A.; Murtula Corbi, R.; Catalan Cuenca, V.; Martin-Cisneros, C. S.; Ymbern, O.; Alonso-Chamorro, J.

2009-01-01

Microbiological laboratories present a growing interest in automated, simple and user-friendly methodologies able to perform simultaneous analysis of a high amount of samples. Analytical tools based on micro-fluidic could play an important role in this field. In this work, the development of an automated micro fluidic system for PCR applications and aimed to monitoring of drinking water quality is presented. The device will be able to determine, simultaneously, fecal pollution indicators and water-transmitted pathogens. Further-more, complemented with DNA pre-concentration and extraction modules, the device would present a highly integrated solution for microbiological diagnostic laboratories. (Author) 13 refs.

Towards self-assembled devices, a carbon nanotube approach

OpenAIRE

Del Rio Castillo, Antonio Esau

2012-01-01

2010/2011 In the last decade the nanostructured carbon materials, especially single walled carbon nanotubes (SWNTs), had emerged as probable substitutes for Silicon in the next generation of electronic devices. This is due to their unique physic and chemical properties. Likewise, scientists all around the world have made a huge effort to introduce carbon materials into the market. Despite this effort, commercial application for carbon nanotubes in electronic devices has not yet been achiev...

Carbon Nanotube Based Molecular Electronics

Science.gov (United States)

Srivastava, Deepak; Saini, Subhash; Menon, Madhu

1998-01-01

Carbon nanotubes and the nanotube heterojunctions have recently emerged as excellent candidates for nanoscale molecular electronic device components. Experimental measurements on the conductivity, rectifying behavior and conductivity-chirality correlation have also been made. While quasi-one dimensional simple heterojunctions between nanotubes with different electronic behavior can be generated by introduction of a pair of heptagon-pentagon defects in an otherwise all hexagon graphene sheet. Other complex 3- and 4-point junctions may require other mechanisms. Structural stability as well as local electronic density of states of various nanotube junctions are investigated using a generalized tight-binding molecular dynamics (GDBMD) scheme that incorporates non-orthogonality of the orbitals. The junctions investigated include straight and small angle heterojunctions of various chiralities and diameters; as well as more complex 'T' and 'Y' junctions which do not always obey the usual pentagon-heptagon pair rule. The study of local density of states (LDOS) reveal many interesting features, most prominent among them being the defect-induced states in the gap. The proposed three and four pointjunctions are one of the smallest possible tunnel junctions made entirely of carbon atoms. Furthermore the electronic behavior of the nanotube based device components can be taylored by doping with group III-V elements such as B and N, and BN nanotubes as a wide band gap semiconductor has also been realized in experiments. Structural properties of heteroatomic nanotubes comprising C, B and N will be discussed.

Micro-Cavity Fluidic Dye Laser

DEFF Research Database (Denmark)

Helbo, Bjarne; Kristensen, Anders; Menon, Aric Kumaran

2003-01-01

We have successfully designed, fabricated and characterized a micro-cavity fluidic dye laser with metallic mirrors, which can be integrated with polymer based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the average pumping power...... threshold for lasing as function of cavity-mirror reflectance, laser dye concentration and cavity length. The laser device is characterized using the laser dye Rhodamine 6G dissolved in ethanol. Lasing is observed, and the influence of dye concentration is investigated....

Dampers, fluidics and the failsafe fallacy [fire protection

International Nuclear Information System (INIS)

Dann, M.; Hodgson, T.

1989-01-01

The fire protection practices adopted at nuclear power stations generally follow the well established principles used throughout industry. Unfortunately, there is one particular area - the interaction with heating, ventilation and air conditioning (HVAC) services - where nuclear power stations pose a seemingly insoluble conflict: that between the need to contain and the need to ventilate. Now, however, solid state fire dampers using power fluidics may promise a solution. One of the key characteristics of a fluidic device is that it is 'solid state', i.e. it has no moving parts. Because of this, its inherent reliability is orders of magnitude greater than a mechanical device. (U.K.)

Fluidic-Based Virtual Aerosurface Shaping

National Research Council Canada - National Science Library

Glezer, Ari

2004-01-01

Recent work on a novel approach to the control of the aerodynamic performance of lifting surfaces by fluidic modification of their apparent aerodynamic shape, or virtual aerosurface shaping is reviewed...

Formation of a vertical MOSFET for charge sensing in a Si micro-fluidic channel

International Nuclear Information System (INIS)

Lyu, Hong-Kun; Kim, Dong-Sun; Shin, Jang-Kyoo; Choi, Pyung; Lee, Jong-Hyun; Park, Hey-Jung; Park, Chin-Sung; Lim, Geun-Bae

2004-01-01

We have formed a fluidic channel that can be used in micro-fluidic systems and fabricated a 3-dimensional vertical metal-oxide semiconductor field-effect transistor (vertical MOSFET) in the convex corner of a Si micro-fluidic channel by using an anisotropic tetramethyl ammonium hydroxide (TMAH) etching solution. A Au/Cr layer was used for the gate metal and might be useful for detecting charged biomolecules. The electrical characteristics of the vertical MOSFET and its operation as a chemical sensor were investigated. At V DS = -5 V and V GS = -5 V the drain current of the device was -22.5 μA and the threshold voltage was about -1.4 V. A non-planar, non-rectangular vertical MOSFET with a trapezoidal gate was transformed into an equivalent rectangularly based one by using a Schwartz-Christoffel transformation. The LEVEL1 device parameters of the vertical MOSFET were extracted from the measured electrical device characteristics and were used in the SPICE simulation for the vertical MOSFET. The measured and the simulated results for the vertical PMOSFET showed relatively good agreement. When the vertical MOSFET was dipped into a thiol DNA solution, the drain current decreased due to charged biomolecules probably being adsorbed on the gate, which indicates that a vertical MOSFET in a Si micro-fluidic channel might be useful for sensing charged biomolecules.

ZnO nanotube-based dye-sensitized solar cell and its application in self-powered devices

Energy Technology Data Exchange (ETDEWEB)

Han Jingbin; Fan Fengru; Xu Chen; Lin Shisheng; Wang Zhonglin [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245 (United States); Wei Min; Duan Xue, E-mail: zhong.wang@mse.gatech.edu, E-mail: weimin@mail.buct.edu.cn [State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

2010-10-08

High-density vertically aligned ZnO nanotube arrays were fabricated on FTO substrates by a simple and facile chemical etching process from electrodeposited ZnO nanorods. The nanotube formation was rationalized in terms of selective dissolution of the (001) polar face. The morphology of the nanotubes can be readily controlled by electrodeposition parameters for the nanorod precursor. By employing the 5.1 {mu}m-length nanotubes as the photoanode for a dye-sensitized solar cell (DSSC), a full-sun conversion efficiency of 1.18% was achieved. Furthermore, we show that the DSSC unit can serve as a robust power source to drive a humidity sensor, with a potential for self-powered devices.

ZnO nanotube-based dye-sensitized solar cell and its application in self-powered devices

KAUST Repository

Han, Jingbin

2010-09-10

Abstract High-density vertically aligned ZnO nanotube arrays were fabricated on FTO substrates by a simple and facile chemical etching process from electrodeposited ZnO nanorods. The nanotube formation was rationalized in terms of selective dissolution of the (001) polar face. The morphology of the nanotubes can be readily controlled by electrodeposition parameters for the nanorod precursor. By employing the 5.1 μm-length nanotubes as the photoanode for a dye-sensitized solar cell (DSSC), a full-sun conversion efficiency of 1.18% was achieved. Furthermore, we show that the DSSC unit can serve as a robust power source to drive a humidity sensor, with a potential for self-powered devices. © 2010 IOP Publishing Ltd.

Fluidic electrodynamics: Approach to electromagnetic propulsion

International Nuclear Information System (INIS)

Martins, Alexandre A.; Pinheiro, Mario J.

2009-01-01

We report on a new methodological approach to electrodynamics based on a fluidic viewpoint. We develop a systematic approach establishing analogies between physical magnitudes and isomorphism (structure-preserving mappings) between systems of equations. This methodological approach allows us to give a general expression for the hydromotive force, thus re-obtaining the Navier-Stokes equation departing from the appropriate electromotive force. From this ground we offer a fluidic approach to different kinds of issues with interest in propulsion, e.g., the force exerted by a charged particle on a body carrying current; the magnetic force between two parallel currents; the Magnus's force. It is shown how the intermingle between the fluid vector fields and electromagnetic fields leads to new insights on their dynamics. The new concepts introduced in this work suggest possible applications to electromagnetic (EM) propulsion devices and the mastery of the principles of producing electric fields of required configuration in plasma medium.

A study on carbon nanotube bridge as a electromechanical memory device

Science.gov (United States)

Kang, Jeong Won; Ha Lee, Jun; Joo Lee, Hoong; Hwang, Ho Jung

2005-04-01

A nanoelectromechanical (NEM) nanotube random access memory (NRAM) device based on carbon nanotube (CNT) was investigated using atomistic simulations. For the CNT-based NEM memory, the mechanical properties of the CNT-bridge and van der Waals interactions between the CNT-bridge and substrate were very important. The critical amplitude of the CNT-bridge was 16% of the length of the CNT-bridge. As molecular dynamics time increased, the CNT-bridge went to the steady state under the electrostatic force with the damping of the potential and the kinetic energies of the CNT-bridge. The interatomic interaction between the CNT-bridge and substrate, value of the CNT-bridge slack, and damping rate of the CNT-bridge were very important for the operation of the NEM memory device as a nonvolatile memory.

3D printed fluidics with embedded analytic functionality for automated reaction optimisation.

Science.gov (United States)

Capel, Andrew J; Wright, Andrew; Harding, Matthew J; Weaver, George W; Li, Yuqi; Harris, Russell A; Edmondson, Steve; Goodridge, Ruth D; Christie, Steven D R

2017-01-01

Additive manufacturing or '3D printing' is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis.

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

Directory of Open Access Journals (Sweden)

Andrew J. Capel

2017-01-01

Full Text Available Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis.

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

Science.gov (United States)

Capel, Andrew J; Wright, Andrew; Harding, Matthew J; Weaver, George W; Li, Yuqi; Harris, Russell A; Edmondson, Steve; Goodridge, Ruth D

2017-01-01

Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis. PMID:28228852

Lightweight carbon nanotube-based structural-energy storage devices for micro unmanned systems

Science.gov (United States)

Rivera, Monica; Cole, Daniel P.; Hahm, Myung Gwan; Reddy, Arava L. M.; Vajtai, Robert; Ajayan, Pulickel M.; Karna, Shashi P.; Bundy, Mark L.

2012-06-01

There is a strong need for small, lightweight energy storage devices that can satisfy the ever increasing power and energy demands of micro unmanned systems. Currently, most commercial and developmental micro unmanned systems utilize commercial-off-the-shelf (COTS) lithium polymer batteries for their energy storage needs. While COTS lithium polymer batteries are the industry norm, the weight of these batteries can account for up to 60% of the overall system mass and the capacity of these batteries can limit mission durations to the order of only a few minutes. One method to increase vehicle endurance without adding mass or sacrificing payload capabilities is to incorporate multiple system functions into a single material or structure. For example, the body or chassis of a micro vehicle could be replaced with a multifunctional material that would serve as both the vehicle structure and the on-board energy storage device. In this paper we present recent progress towards the development of carbon nanotube (CNT)-based structural-energy storage devices for micro unmanned systems. Randomly oriented and vertically aligned CNT-polymer composite electrodes with varying degrees of flexibility are used as the primary building blocks for lightweight structural-supercapacitors. For the purpose of this study, the mechanical properties of the CNT-based electrodes and the charge-discharge behavior of the supercapacitor devices are examined. Because incorporating multifunctionality into a single component often degrades the properties or performance of individual structures, the performance and property tradeoffs of the CNT-based structural-energy storage devices will also be discussed.

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

OpenAIRE

Andrew J. Capel; Andrew Wright; Matthew J. Harding; George W. Weaver; Yuqi Li; Russell A. Harris; Steve Edmondson; Ruth D. Goodridge; Steven D. R. Christie

2017-01-01

Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro and milli-scale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multi-functional fluidic devices with embedded reaction moni...

Dielectric Elastomers for Fluidic and Biomedical Applications

Science.gov (United States)

McCoul, David James

Dielectric elastomers have demonstrated tremendous potential as high-strain electromechanical transducers for a myriad of novel applications across all engineering disciplines. Because their soft, viscoelastic mechanical properties are similar to those of living tissues, dielectric elastomers have garnered a strong foothold in a plethora of biomedical and biomimetic applications. Dielectric elastomers consist of a sheet of stretched rubber, or elastomer, coated on both sides with compliant electrode materials; application of a voltage generates an electrostatic pressure that deforms the elastomer. They can function as soft generators, sensors, or actuators, and this last function is the focus of this dissertation. Many design configurations are possible, such as stacks, minimum energy structures, interpenetrating polymer networks, shape memory dielectric elastomers, and others; dielectric elastomers are already being applied to many fields of biomedicine. The first part of the original research presented in this dissertation details a PDMS microfluidic system paired with a dielectric elastomer stack actuator of anisotropically prestrained VHB(TM) 4910 (3M(TM)) and single-walled carbon nanotubes. These electroactive microfluidic devices demonstrated active increases in microchannel width when 3 and 4 kV were applied. Fluorescence microscopy also indicated an accompanying increase in channel depth with actuation. The cross-sectional area strains at 3 and 4 kV were approximately 2.9% and 7.4%, respectively. The device was then interfaced with a syringe pump, and the pressure was measured upstream. Linear pressure-flow plots were developed, which showed decreasing fluidic resistance with actuation, from 0.192 psi/(microL/min) at 0 kV, to 0.160 and 0.157 psi/(microL/min) at 3 and 4 kV, respectively. This corresponds to an ~18% drop in fluidic resistance at 4 kV. Active de-clogging was tested in situ with the device by introducing ~50 microm diameter PDMS microbeads and

DNA Assembly in 3D Printed Fluidics.

Directory of Open Access Journals (Sweden)

William G Patrick

Full Text Available The process of connecting genetic parts-DNA assembly-is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly print fluidic devices and supporting hardware. 3D printed micro- and millifluidic devices are inexpensive, easy to make and quick to produce. We demonstrate Golden Gate DNA assembly in 3D-printed fluidics with reaction volumes as small as 490 nL, channel widths as fine as 220 microns, and per unit part costs ranging from $0.61 to $5.71. A 3D-printed syringe pump with an accompanying programmable software interface was designed and fabricated to operate the devices. Quick turnaround and inexpensive materials allowed for rapid exploration of device parameters, demonstrating a manufacturing paradigm for designing and fabricating hardware for synthetic biology.

The multi-mode modulator: A versatile fluidic device for two-dimensional gas chromatography.

Science.gov (United States)

Seeley, John V; Schimmel, Nicolaas E; Seeley, Stacy K

2018-02-09

A fluidic device called the multi-mode modulator (MMM) has been developed for use as a comprehensive two-dimensional gas chromatography (GC x GC) modulator. The MMM can be employed in a wide range of capacities including as a traditional heart-cutting device, a low duty cycle GC x GC modulator, and a full transfer GC x GC modulator. The MMM is capable of producing narrow component pulses (widths <50ms) while operating at flows compatible with high resolution chromatography. The sample path of modulated components is confined to the interior of a joining capillary. The joining capillary dimensions and the position of the columns within the joining capillary can be optimized for the selected modulation mode. Furthermore, the joining capillary can be replaced easily and inexpensively if it becomes fouled due to sample matrix components or column bleed. The principles of operation of the MMM are described and its efficacy is demonstrated as a heart-cutting device and as a GC x GC modulator. Copyright © 2017 Elsevier B.V. All rights reserved.

Hybrid Macro-Micro Fluidics System for a Chip-Based Biosensor

National Research Council Canada - National Science Library

Tamanaha, C. R; Whitman, L. J; Colton, R.J

2002-01-01

We describe the engineering of a hybrid fluidics platform for a chip-based biosensor system that combines high-performance microfluidics components with powerful, yet compact, millimeter-scale pump and valve actuators...

A microfluidic device for simultaneous measurement of viscosity and flow rate of blood in a complex fluidic network

OpenAIRE

Jun Kang, Yang; Yeom, Eunseop; Lee, Sang-Joon

2013-01-01

Blood viscosity has been considered as one of important biophysical parameters for effectively monitoring variations in physiological and pathological conditions of circulatory disorders. Standard previous methods make it difficult to evaluate variations of blood viscosity under cardiopulmonary bypass procedures or hemodialysis. In this study, we proposed a unique microfluidic device for simultaneously measuring viscosity and flow rate of whole blood circulating in a complex fluidic network i...

Integrated optics nano-opto-fluidic sensor based on whispering gallery modes for picoliter volume refractometry

International Nuclear Information System (INIS)

Gilardi, Giovanni; Beccherelli, Romeo

2013-01-01

We propose and numerically investigate an integrated optics refractometric nano-opto-fluidic sensor based on whispering gallery modes in sapphire microspheres. A measurand fluid is injected in a micromachined reservoir defined in between the microsphere and an optical waveguide. The wavelength shift due to changes in the refractive index of the measurand fluid are studied for a set of different configurations by the finite element method and a high sensitivity versus fluid volume is found. The proposed device can be tailored to work with a minimum fluid volume of 1 pl and a sensitivity up of 2000 nm/(RIU·nl). We introduce a figure of merit which quantifies the amplifying effect on the sensitivity of high quality factor resonators and allows us to compare different devices. (paper)

Sensors based on carbon nanotube field-effect transistors and molecular recognition approaches

OpenAIRE

Cid Salavert, Cristina Carlota

2009-01-01

The general objective of this thesis is to develop chemical sensors whose sensing capacities are based on the principle of molecular recognition and where the transduction is carried out by single-walled carbon nanotubes (SWCNT).The sensing device used is the carbon nanotube field-effect transistor (CNTFET). The new structure of the CNTFET allows nanotubes to be integrated at the surface of the devices, thus exploiting SWCNTs' sensitivity to changes in their environment. The functionalization...

A characteristic analysis of the fluidic muscle cylinder

Science.gov (United States)

Kim, Dong-Soo; Bae, Sang-Kyu; Hong, Sung-In

2005-12-01

The fluidic muscle cylinder consists of an air bellows tube, flanges and lock nuts. It's features are softness of material and motion, simplicity of structure, low production cost and high power efficiency. Recently, unlikely the pneumatic cylinder, the fluidic muscle cylinder without air leakage, stick slip, friction, and seal was developed as a new concept actuator. It has the characteristics such as light weight, low price, high response, durable design, long life, high power, high contraction, which is innovative product fulfilling RT(Robot Technology) which is one of the nation-leading next generation strategy technologies 6T as well as cleanness technology. The application fields of the fluidic muscle cylinder are so various like fatigue tester, brake, accelerator, high technology testing device such as driving simulator, precise position, velocity, intelligent servo actuator under special environment such as load controlling system, and intelligent robot. In this study, we carried out the finite element modeling and analysis about the main design variables such as contraction ration and force, diameter increment of fluidic muscle cylinder. On the basis of finite element analysis, the prototype of fluidic muscle cylinder was manufactured and tested. Finally, we compared the results between the test and the finite element analysis.

Detached-Eddy Simulation of a Fluidic Device for a Prediction of Pressure Loss Characteristics in a Low Flow Mode

International Nuclear Information System (INIS)

Lim, Sang Gyu; Lee, Suk Ho; Kim, Han Gon

2010-01-01

The Advanced Power Reactor 1400(APR1400) adopts a passive flow controller in Safety Injection Tanks (SITs) as one of Advanced Design Features (ADFs). This device, called a 'Fluidic Device (FD)', controls the flow rate of safety injection water in a passive manner. A flow control mechanism varies the flow resistance in the vortex chamber corresponding to the SIT water level hence the flow rate can be adjusted by the specific flow resistance in a specific flow regime. A full-scale test was performed and the test results met the design requirement of APR1400. To enhance the performance of the FD more effectively, a series of CFD analysis were implemented and remedy of design modification was proposed on the basis of a series of CFD analysis. The results of CFD analysis showed that total discharge time of the fluidic device is to be increased by enhancing the K-factor in consequence of changing the control nozzle angle. However, a tendency of a pressure loss was under-estimated as a limitation of turbulence models such as Reynolds Averaged Navier- Stokes (RANS) models compared to the experimental data. This paper shows that pressure loss characteristics of the FD can be predicted using a Detached-Eddy Simulation (DES) turbulence model, which can provide valuable flow characteristics far exceeding RANS simulations

Memory operation devices based on light-illumination ambipolar carbon-nanotube thin-film-transistors

International Nuclear Information System (INIS)

Aïssa, B.; Nedil, M.; Kroeger, J.; Haddad, T.; Rosei, F.

2015-01-01

We report the memory operation behavior of a light illumination ambipolar single-walled carbon nanotube thin film field-effect transistors devices. In addition to the high electronic-performance, such an on/off transistor-switching ratio of 10 4 and an on-conductance of 18 μS, these memory devices have shown a high retention time of both hole and electron-trapping modes, reaching 2.8 × 10 4  s at room temperature. The memory characteristics confirm that light illumination and electrical field can act as an independent programming/erasing operation method. This could be a fundamental step toward achieving high performance and stable operating nanoelectronic memory devices

Frontiers of graphene and carbon nanotubes devices and applications

CERN Document Server

2015-01-01

This book focuses on carbon nanotubes and graphene as representatives of nano-carbon materials, and describes the growth of new technology and applications of new devices. As new devices and as new materials, nano-carbon materials are expected to be world pioneers that could not have been realized with conventional semiconductor materials, and as those that extend the limits of conventional semiconductor performance. This book introduces the latest achievements of nano-carbon devices, processes, and technology growth. It is anticipated that these studies will also be pioneers in the development of future research of nano-carbon devices and materials. This book consists of 18 chapters. Chapters 1 to 8 describe new device applications and new growth methods of graphene, and Chapters 9 to 18, those of carbon nanotubes. It is expected that by increasing the advantages and overcoming the weak points of nanocarbon materials, a new world that cannot be achieved with conventional materials will be greatly expanded. W...

Carbon nanotube based pressure sensor for flexible electronics

International Nuclear Information System (INIS)

So, Hye-Mi; Sim, Jin Woo; Kwon, Jinhyeong; Yun, Jongju; Baik, Seunghyun; Chang, Won Seok

2013-01-01

Highlights: • The electromechanical change of vertically aligned carbon nanotubes. • Fabrication of CNT field-effect transistor on flexible substrate. • CNT based FET integrated active pressure sensor. • The integrated device yields an increase in the source-drain current under pressure. - Abstract: A pressure sensor was developed based on an arrangement of vertically aligned carbon nanotubes (VACNTs) supported by a polydimethylsiloxane (PDMS) matrix. The VACNTs embedded in the PDMS matrix were structurally flexible and provided repeated sensing operation due to the high elasticities of both the polymer and the carbon nanotubes (CNTs). The conductance increased in the presence of a loading pressure, which compressed the material and induced contact between neighboring CNTs, thereby producing a dense current path and better CNT/metal contacts. To achieve flexible functional electronics, VACNTs based pressure sensor was integrated with field-effect transistor, which is fabricated using sprayed semiconducting carbon nanotubes on plastic substrate

Carbon nanotube based pressure sensor for flexible electronics

Energy Technology Data Exchange (ETDEWEB)

So, Hye-Mi [Department of Nano Mechanics, Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Daejeon 305-343 (Korea, Republic of); Sim, Jin Woo [Advanced Nano Technology Ltd., Seoul 132-710 (Korea, Republic of); Kwon, Jinhyeong [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of); Yun, Jongju; Baik, Seunghyun [SKKU Advanced Institute of Nanotechnology (SAINT), Department of Energy Science and School of Mechanical Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Chang, Won Seok, E-mail: paul@kimm.re.kr [Department of Nano Mechanics, Nanomechanical Systems Research Division, Korea Institute of Machinery and Materials, Daejeon 305-343 (Korea, Republic of)

2013-12-15

Highlights: • The electromechanical change of vertically aligned carbon nanotubes. • Fabrication of CNT field-effect transistor on flexible substrate. • CNT based FET integrated active pressure sensor. • The integrated device yields an increase in the source-drain current under pressure. - Abstract: A pressure sensor was developed based on an arrangement of vertically aligned carbon nanotubes (VACNTs) supported by a polydimethylsiloxane (PDMS) matrix. The VACNTs embedded in the PDMS matrix were structurally flexible and provided repeated sensing operation due to the high elasticities of both the polymer and the carbon nanotubes (CNTs). The conductance increased in the presence of a loading pressure, which compressed the material and induced contact between neighboring CNTs, thereby producing a dense current path and better CNT/metal contacts. To achieve flexible functional electronics, VACNTs based pressure sensor was integrated with field-effect transistor, which is fabricated using sprayed semiconducting carbon nanotubes on plastic substrate.

Application of fluidic lens technology to an adaptive holographic optical element see-through autophoropter

Science.gov (United States)

Chancy, Carl H.

A device for performing an objective eye exam has been developed to automatically determine ophthalmic prescriptions. The closed loop fluidic auto-phoropter has been designed, modeled, fabricated and tested for the automatic measurement and correction of a patient's prescriptions. The adaptive phoropter is designed through the combination of a spherical-powered fluidic lens and two cylindrical fluidic lenses that are orientated 45o relative to each other. In addition, the system incorporates Shack-Hartmann wavefront sensing technology to identify the eye's wavefront error and corresponding prescription. Using the wavefront error information, the fluidic auto-phoropter nulls the eye's lower order wavefront error by applying the appropriate volumes to the fluidic lenses. The combination of the Shack-Hartmann wavefront sensor the fluidic auto-phoropter allows for the identification and control of spherical refractive error, as well as cylinder error and axis; thus, creating a truly automated refractometer and corrective system. The fluidic auto-phoropter is capable of correcting defocus error ranging from -20D to 20D and astigmatism from -10D to 10D. The transmissive see-through design allows for the observation of natural scenes through the system at varying object planes with no additional imaging optics in the patient's line of sight. In this research, two generations of the fluidic auto-phoropter are designed and tested; the first generation uses traditional glass optics for the measurement channel. The second generation of the fluidic auto-phoropter takes advantage of the progress in the development of holographic optical elements (HOEs) to replace all the traditional glass optics. The addition of the HOEs has enabled the development of a more compact, inexpensive and easily reproducible system without compromising its performance. Additionally, the fluidic lenses were tested during a National Aeronautics Space Administration (NASA) parabolic flight campaign, to

Recent advances in molecular electronics based on carbon nanotubes.

Science.gov (United States)

Bourgoin, Jean-Philippe; Campidelli, Stéphane; Chenevier, Pascale; Derycke, Vincent; Filoramo, Arianna; Goffman, Marcelo F

2010-01-01

Carbon nanotubes (CNTs) have exceptional physical properties that make them one of the most promising building blocks for future nanotechnologies. They may in particular play an important role in the development of innovative electronic devices in the fields of flexible electronics, ultra-high sensitivity sensors, high frequency electronics, opto-electronics, energy sources and nano-electromechanical systems (NEMS). Proofs of concept of several high performance devices already exist, usually at the single device level, but there remain many serious scientific issues to be solved before the viability of such routes can be evaluated. In particular, the main concern regards the controlled synthesis and positioning of nanotubes. In our opinion, truly innovative use of these nano-objects will come from: (i) the combination of some of their complementary physical properties, such as combining their electrical and mechanical properties, (ii) the combination of their properties with additional benefits coming from other molecules grafted on the nanotubes, and (iii) the use of chemically- or bio-directed self-assembly processes to allow the efficient combination of several devices into functional arrays or circuits. In this article, we outline the main issues concerning the development of carbon nanotubes based electronics applications and review our recent results in the field.

Memory operation devices based on light-illumination ambipolar carbon-nanotube thin-film-transistors

Energy Technology Data Exchange (ETDEWEB)

Aïssa, B., E-mail: aissab@emt.inrs.ca [Qatar Environment and Energy Research Institute (QEERI), Qatar Foundation, P.O. Box 5825, Doha (Qatar); Centre Energie, Matériaux et Télécommunications, INRS, 1650, Boulevard Lionel-Boulet Varennes, Quebec J3X 1S2 (Canada); Nedil, M. [Telebec Wireless Underground Communication Laboratory, UQAT, 675, 1ère Avenue, Val d' Or, Quebec J9P 1Y3 (Canada); Kroeger, J. [NanoIntegris & Raymor Nanotech, Raymor Industries Inc., 3765 La Vérendrye, Boisbriand, Quebec J7H 1R8 (Canada); Haddad, T. [Department of Mechanical Engineering, McGill University, Montreal, Quebec H3A 0B8 (Canada); Rosei, F. [Centre Energie, Matériaux et Télécommunications, INRS, 1650, Boulevard Lionel-Boulet Varennes, Quebec J3X 1S2 (Canada)

2015-09-28

We report the memory operation behavior of a light illumination ambipolar single-walled carbon nanotube thin film field-effect transistors devices. In addition to the high electronic-performance, such an on/off transistor-switching ratio of 10{sup 4} and an on-conductance of 18 μS, these memory devices have shown a high retention time of both hole and electron-trapping modes, reaching 2.8 × 10{sup 4} s at room temperature. The memory characteristics confirm that light illumination and electrical field can act as an independent programming/erasing operation method. This could be a fundamental step toward achieving high performance and stable operating nanoelectronic memory devices.

Outstanding field emission properties of wet-processed titanium dioxide coated carbon nanotube based field emission devices

Energy Technology Data Exchange (ETDEWEB)

Xu, Jinzhuo; Ou-Yang, Wei, E-mail: ouyangwei@phy.ecnu.edu.cn; Chen, Xiaohong; Guo, Pingsheng; Piao, Xianqing; Sun, Zhuo [Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Xu, Peng; Wang, Miao [Department of Physics, Zhejiang University, 38 ZheDa Road, Hangzhou 310027 (China); Li, Jun [Department of Electronic Science and Technology, Tongji University, 4800 Caoan Road, Shanghai 201804 (China)

2015-02-16

Field emission devices using a wet-processed composite cathode of carbon nanotube films coated with titanium dioxide exhibit outstanding field emission characteristics, including ultralow turn on field of 0.383 V μm{sup −1} and threshold field of 0.657 V μm{sup −1} corresponding with a very high field enhancement factor of 20 000, exceptional current stability, and excellent emission uniformity. The improved field emission properties are attributed to the enhanced edge effect simultaneously with the reduced screening effect, and the lowered work function of the composite cathode. In addition, the highly stable electron emission is found due to the presence of titanium dioxide nanoparticles on the carbon nanotubes, which prohibits the cathode from the influence of ions and free radical created in the emission process as well as residual oxygen gas in the device. The high-performance solution-processed composite cathode demonstrates great potential application in vacuum electronic devices.

Opto-fluidics based microscopy and flow cytometry on a cell phone for blood analysis.

Science.gov (United States)

Zhu, Hongying; Ozcan, Aydogan

2015-01-01

Blood analysis is one of the most important clinical tests for medical diagnosis. Flow cytometry and optical microscopy are widely used techniques to perform blood analysis and therefore cost-effective translation of these technologies to resource limited settings is critical for various global health as well as telemedicine applications. In this chapter, we review our recent progress on the integration of imaging flow cytometry and fluorescent microscopy on a cell phone using compact, light-weight and cost-effective opto-fluidic attachments integrated onto the camera module of a smartphone. In our cell-phone based opto-fluidic imaging cytometry design, fluorescently labeled cells are delivered into the imaging area using a disposable micro-fluidic chip that is positioned above the existing camera unit of the cell phone. Battery powered light-emitting diodes (LEDs) are butt-coupled to the sides of this micro-fluidic chip without any lenses, which effectively acts as a multimode slab waveguide, where the excitation light is guided to excite the fluorescent targets within the micro-fluidic chip. Since the excitation light propagates perpendicular to the detection path, an inexpensive plastic absorption filter is able to reject most of the scattered light and create a decent dark-field background for fluorescent imaging. With this excitation geometry, the cell-phone camera can record fluorescent movies of the particles/cells as they are flowing through the microchannel. The digital frames of these fluorescent movies are then rapidly processed to quantify the count and the density of the labeled particles/cells within the solution under test. With a similar opto-fluidic design, we have recently demonstrated imaging and automated counting of stationary blood cells (e.g., labeled white blood cells or unlabeled red blood cells) loaded within a disposable cell counting chamber. We tested the performance of this cell-phone based imaging cytometry and blood analysis platform

Flexible electroluminescent device with inkjet-printed carbon nanotube electrodes

Science.gov (United States)

Azoubel, Suzanna; Shemesh, Shay; Magdassi, Shlomo

2012-08-01

Carbon nanotube (CNTs) inks may provide an effective route for producing flexible electronic devices by digital printing. In this paper we report on the formulation of highly concentrated aqueous CNT inks and demonstrate the fabrication of flexible electroluminescent (EL) devices by inkjet printing combined with wet coating. We also report, for the first time, on the formation of flexible EL devices in which all the electrodes are formed by inkjet printing of low-cost multi-walled carbon nanotubes (MWCNTs). Several flexible EL devices were fabricated by using different materials for the production of back and counter electrodes: ITO/MWCNT and MWCNT/MWCNT. Transparent electrodes were obtained either by coating a thin layer of the CNTs or by inkjet printing a grid which is composed of empty cells surrounded by MWCNTs. It was found that the conductivity and transparency of the electrodes are mainly controlled by the MWCNT film thickness, and that the dominant factor in the luminance intensity is the transparency of the electrode.

Carbon nanotubes for gas detection: materials preparation and device assembly

International Nuclear Information System (INIS)

Terranova, M L; Lucci, M; Orlanducci, S; Tamburri, E; Sessa, V; Reale, A; Carlo, A Di

2007-01-01

An efficient sensing device for NH 3 and NO x detection has been realized using ordered arrays of single-walled C nanotubes deposited onto an interdigitated electrode platform operating at room temperature. The sensing material has been prepared using several chemical-physical techniques for purification and positioning of the nanotubes inside the electrode gaps. In particular, both DC and AC fields have been applied in order to move and to align the nanostructures by electrophoresis and dielectrophoresis processes. We investigated the effects of different voltages applied to a gate contact on the back side of the substrate on the performances of the device and found that for different gas species (NH 3 , NO x ) a constant gate bias increases the sensitivity for gas detection. Moreover, in this paper we demonstrate that a pulsed bias applied to the gate contact facilitates the gas interaction with the nanotubes, either reducing the absorption times or accelerating the desorption times, thus providing a fast acceleration and a dramatic improvement of the time dependent behaviour of the device

Photovoltaic device using single wall carbon nanotubes and method of fabricating the same

Science.gov (United States)

Biris, Alexandru S.; Li, Zhongrui

2012-11-06

A photovoltaic device and methods for forming the same. In one embodiment, the photovoltaic device has a silicon substrate, and a film comprising a plurality of single wall carbon nanotubes disposed on the silicon substrate, wherein the plurality of single wall carbon nanotubes forms a plurality of heterojunctions with the silicon in the substrate.

Carbon-nanotube-based liquids: a new class of nanomaterials and their applications

International Nuclear Information System (INIS)

Phan, Ngoc Minh; Nguyen, Manh Hong; Phan, Hong Khoi; Bui, Hung Thang

2014-01-01

Carbon-nanotube-based liquids—a new class of nanomaterials—have shown many interesting properties and distinctive features offering unprecedented potential for many applications. This paper summarizes the recent progress on the study of the preparation, characterization and properties of carbon-nanotube-based liquids including so-called nanofluids, nanolubricants and different kinds of nanosolutions containing multi-walled carbon nanotubes/single-walled carbon nanotubes/graphene. A broad range of current and future applications of these nanomaterials in the fields of energy saving, power electronic and optoelectronic devices, biotechnology and agriculture are presented. The paper also identifies challenges and opportunities for future research. (paper)

Solenoid Driven Pressure Valve System: Toward Versatile Fluidic Control in Paper Microfluidics.

Science.gov (United States)

Kim, Taehoon H; Hahn, Young Ki; Lee, Jungmin; van Noort, Danny; Kim, Minseok S

2018-02-20

As paper-based diagnostics has become predominantly driven by more advanced microfluidic technology, many of the research efforts are still focused on developing reliable and versatile fluidic control devices, apart from improving sensitivity and reproducibility. In this work, we introduce a novel and robust paper fluidic control system enabling versatile fluidic control. The system comprises a linear push-pull solenoid and an Arduino Uno microcontroller. The precisely controlled pressure exerted on the paper stops the flow. We first determined the stroke distance of the solenoid to obtain a constant pressure while examining the fluidic time delay as a function of the pressure. Results showed that strips of grade 1 chromatography paper had superior reproducibility in fluid transport. Next, we characterized the reproducibility of the fluidic velocity which depends on the type and grade of paper used. As such, we were able to control the flow velocity on the paper and also achieve a complete stop of flow with a pressure over 2.0 MPa. Notably, after the actuation of the pressure driven valve (PDV), the previously pressed area regained its original flow properties. This means that, even on a previously pressed area, multiple valve operations can be successfully conducted. To the best of our knowledge, this is the first demonstration of an active and repetitive valve operation in paper microfluidics. As a proof of concept, we have chosen to perform a multistep detection system in the form of an enzyme-linked immunosorbent assay with mouse IgG as the target analyte.

Hydrodynamics of Safety Injection Tank with Fluidic Device in Recent Regulation

International Nuclear Information System (INIS)

Bang, Young Seok; Yoo, Seung Hun

2016-01-01

Safety Injection Tank (SIT) with Fluidic Device (FD) has been used in several APR1400 nuclear power plants. It was designed to provide a longer passive safety injection than the existing accumulator to improve the safety for Large Break Loss-of-Coolant Accident (LBLOCA) by changing the injected flow through the FD and the standpipe of the SIT. As a result, high flow injection phase and the subsequent low flow one can be achieved as longer than the existing accumulator. The present paper discusses the major concerns related to SIT hydrodynamics and the directions to resolution recently concerned. Modeling of SIT/FD by total hydraulic resistances, potential of nitrogen intrusion, and effect of initial pressure of SIT testing are included. Based on the discussion, a table of the important phenomena of the SIT/FD was proposed with the relevancy of the calculation models applied. The present paper discussed the SIT hydrodynamics including the modeling of SIT/FD by total hydraulic resistances, potential of nitrogen intrusion, and effect of initial pressure of SIT testing. Also a table of the important phenomena of the SIT/FD was proposed with the relevancy of the calculation models applied. The following conclusions are obtained uncertainty due to the assumption of the total Kfactor as constant for high flow, transition phase, and low flow phase should be considered and nitrogen intrusion phenomena during the transition phase should be considered with a conservatism, especially considering the current situation of nonmeasuring the standpipe level

Hydrodynamics of Safety Injection Tank with Fluidic Device in Recent Regulation

Energy Technology Data Exchange (ETDEWEB)

Bang, Young Seok; Yoo, Seung Hun [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

2016-10-15

Safety Injection Tank (SIT) with Fluidic Device (FD) has been used in several APR1400 nuclear power plants. It was designed to provide a longer passive safety injection than the existing accumulator to improve the safety for Large Break Loss-of-Coolant Accident (LBLOCA) by changing the injected flow through the FD and the standpipe of the SIT. As a result, high flow injection phase and the subsequent low flow one can be achieved as longer than the existing accumulator. The present paper discusses the major concerns related to SIT hydrodynamics and the directions to resolution recently concerned. Modeling of SIT/FD by total hydraulic resistances, potential of nitrogen intrusion, and effect of initial pressure of SIT testing are included. Based on the discussion, a table of the important phenomena of the SIT/FD was proposed with the relevancy of the calculation models applied. The present paper discussed the SIT hydrodynamics including the modeling of SIT/FD by total hydraulic resistances, potential of nitrogen intrusion, and effect of initial pressure of SIT testing. Also a table of the important phenomena of the SIT/FD was proposed with the relevancy of the calculation models applied. The following conclusions are obtained uncertainty due to the assumption of the total Kfactor as constant for high flow, transition phase, and low flow phase should be considered and nitrogen intrusion phenomena during the transition phase should be considered with a conservatism, especially considering the current situation of nonmeasuring the standpipe level.

Micro-Fluidic Dye Ring Laser - Experimental Tuning of the Wavelength and Numerical Simulation of the Cavity Modes

DEFF Research Database (Denmark)

Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Niels Asger

2006-01-01

We demonstrate wavelength tuning of a micro-fluidic dye ring laser. Wavelength tunability is obtained by controlling the liquid dye concentration. The device performance is modelled by FEM simulations supporting a ray-tracing view.......We demonstrate wavelength tuning of a micro-fluidic dye ring laser. Wavelength tunability is obtained by controlling the liquid dye concentration. The device performance is modelled by FEM simulations supporting a ray-tracing view....

An experimental study of the flow characteristics of fluidic device in a passive safety injection tank

International Nuclear Information System (INIS)

Cho, Seok; Song, Chul Hwa; Won, Suon Yeon; Min, Kyong Ho; Chung, Moon Ki

1998-01-01

It is considered to adopt passive safety injection tank (SIT) as a enhanced safety feature in KNGR. Passive SIT employs a vortex chamber as a fluidic device, which control injection flow rate passively by the variation of flow resistance produced by vortex intensity within the vortex chamber. To investigate the flow characteristics of the vortex chamber many tests have been carried out by using small-scale test facility. In this report the effects of geometric parameters of vortex chamber on discharge flow characteristics and the velocity measurement result of flow field, measured by PIV, are presented and discussed. (author). 25 refs., 11 tabs., 31 figs

Numerical Studies of a Fluidic Diverter for Flow Control

Science.gov (United States)

Gokoglu, Suleyman A.; Kuczmarski, Maria A.; Culley, Dennis E.; Raghu, Surya

2009-01-01

The internal flow structure in a specific fluidic diverter is studied over a range from low subsonic to sonic inlet conditions by a time-dependent numerical analysis. The understanding will aid in the development of fluidic diverters with minimum pressure losses and advanced designs of flow control actuators. The velocity, temperature and pressure fields are calculated for subsonic conditions and the self-induced oscillatory behavior of the flow is successfully predicted. The results of our numerical studies have excellent agreement with our experimental measurements of oscillation frequencies. The acoustic speed in the gaseous medium is determined to be a key factor for up to sonic conditions in governing the mechanism of initiating the oscillations as well as determining its frequency. The feasibility of employing plasma actuation with a minimal perturbation level is demonstrated in steady-state calculations to also produce oscillation frequencies of our own choosing instead of being dependent on the fixed-geometry fluidic device.

Carbon Nanotubes and Graphene for Flexible Electrochemical Energy Storage: from Materials to Devices.

Science.gov (United States)

Wen, Lei; Li, Feng; Cheng, Hui-Ming

2016-06-01

Flexible electrochemical energy storage (FEES) devices have received great attention as a promising power source for the emerging field of flexible and wearable electronic devices. Carbon nanotubes (CNTs) and graphene have many excellent properties that make them ideally suited for use in FEES devices. A brief definition of FEES devices is provided, followed by a detailed overview of various structural models for achieving different FEES devices. The latest research developments on the use of CNTs and graphene in FEES devices are summarized. Finally, future prospects and important research directions in the areas of CNT- and graphene-based flexible electrode synthesis and device integration are discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Micro fluidic System for Culturing and Monitoring of Neuronal Cells and Tissue

DEFF Research Database (Denmark)

Bakmand, Tanya; Waagepetersen, Helle S.

The aim of this Ph.D. project was to combine experience within cell and tissue culturing, electrochemistry and microfabrication in order to develop an in vivo-like fluidic culturing platform, challenging the traditional culturing methods. The first goal was to develope a fluidic system for cultur...... with mass production. The last part of this thesis also includes perspectives on how to expand the latest designed device to facilitate culturing of tissue and co-culturing of cells....

Separation control with fluidic oscillators in water

Science.gov (United States)

Schmidt, H.-J.; Woszidlo, R.; Nayeri, C. N.; Paschereit, C. O.

2017-08-01

The present study assesses the applicability of fluidic oscillators for separation control in water. The first part of this work evaluates the properties of the fluidic oscillators including frequency, cavitation effects, and exerted thrust. Derived from the governing internal dynamics, the oscillation frequency is found to scale directly with the jet's exit velocity and the size of the fluidic oscillator independent of the working fluid. Frequency data from various experiments collapse onto a single curve. The occurrence of cavitation is examined by visual inspection and hydrophone measurements. The oscillation frequency is not affected by cavitation because it does not occur inside the oscillators. The spectral information obtained with the hydrophone provide a reliable indicator for the onset of cavitation at the exit. The performance of the fluidic oscillators for separation control on a bluff body does not seem to be affected by the presence of cavitation. The thrust exerted by an array of fluidic oscillators with water as the working fluid is measured to be even larger than theoretically estimated values. The second part of the presented work compares the performance of fluidic oscillators for separation control in water with previous results in air. The array of fluidic oscillators is installed into the rear end of a bluff body model. The drag improvements based on force balance measurements agree well with previous wind tunnel experiments on the same model. The flow field is examined by pressure measurements and with particle image velocimetry. Similar performance and flow field characteristics are observed in both water and air.

FLUIDICS DEVICE FOR ASSAY

DEFF Research Database (Denmark)

2007-01-01

The present invention relates to a device for use in performing assays on standard laboratory solid supports whereon chemical entities are attached. The invention furthermore relates to the use of such a device and a kit comprising such a device. The device according to the present invention is a...

Fusion-bonded fluidic interconnects

International Nuclear Information System (INIS)

Fazal, I; Elwenspoek, M C

2008-01-01

A new approach to realize fluidic interconnects based on the fusion bonding of glass tubes with silicon is presented. Fusion bond strength analyses have been carried out. Experiments with plain silicon wafers and coated with silicon oxide and silicon nitride are performed. The obtained results are discussed in terms of the homogeneity and strength of fusion bond. High pressure testing shows that the bond strength is large enough for most applications of fluidic interconnects. The bond strength for 525 µm thick silicon, with glass tubes having an outer diameter of 6 mm and with a wall thickness of 2 mm, is more than 60 bars after annealing at a temperature of 800 °C

Performance Verification for Safety Injection Tank with Fluidic Device

International Nuclear Information System (INIS)

Yune, Seok Jeong; Kim, Da Yong

2014-01-01

In LBLOCA, the SITs of a conventional nuclear power plant deliver excessive cooling water to the reactor vessel causing the water to flow into the containment atmosphere. In an effort to make it more efficient, Fluidic Device (FD) is installed inside a SIT of Advanced Power Reactor 1400 (APR 1400). FD, a complete passive controller which doesn't require actuating power, controls injection flow rates which are susceptible to a change in the flow resistance inside a vortex chamber of FD. When SIT Emergency Core Cooling (ECC) water level is above the top of the stand pipe, the water enters the vortex chamber through both the top of the stand pipe and the control ports resulting in injection of the water at a large flow rate. When the water level drops below the top of the stand pipe, the water only enters the vortex chamber through the control ports resulting in vortex formation in the vortex chamber and a relatively small flow injection. Performance verification of SIT shall be carried out because SITs play an integral role to mitigate accidents. In this paper, the performance verification method of SIT with FD is presented. In this paper, the equations for calculation of flow resistance coefficient (K) are induced to evaluate on-site performance of APR 1400 SIT with FD. Then, the equations are applied to the performance verification of SIT with FD and good results are obtained

A novel drug delivery of 5-fluorouracil device based on TiO{sub 2}/ZnS nanotubes

Energy Technology Data Exchange (ETDEWEB)

Mendonça Faria, Henrique Antonio, E-mail: henrique.fisica@ifsc.usp.br [Institute of Physics and Chemistry, Federal University of Itajubá (UNIFEI), Av. BPS, 1303, Pinheirinho, Itajubá, MG, PO Box 50, CEP: 37500-903 (Brazil); Nanomedicine and Nanotoxicology Laboratory, São Carlos Institute of Physics, University of São Paulo. Av. Trabalhador São-carlense, 400, Arnold Schimidt, São Carlos, SP CEP: 13566-590 (Brazil); Alencar de Queiroz, Alvaro Antonio, E-mail: alencar@unifei.edu.br [Institute of Physics and Chemistry, Federal University of Itajubá (UNIFEI), Av. BPS, 1303, Pinheirinho, Itajubá, MG, PO Box 50, CEP: 37500-903 (Brazil)

2015-11-01

The structural and electronic properties of titanium oxide nanotubes (TiO{sub 2}) have attracted considerable attention for the development of therapeutic devices and imaging probes for nanomedicine. However, the fluorescence response of TiO{sub 2} has typically been within ultraviolet spectrum. In this study, the surface modification of TiO{sub 2} nanotubes with ZnS quantum dots was found to produce a red shift in the ultra violet emission band. The TiO{sub 2} nanotubes used in this work were obtained by sol–gel template synthesis. The ZnS quantum dots were deposited onto TiO{sub 2} nanotube surface by a micelle-template inducing reaction. The structure and morphology of the resulting hybrid TiO{sub 2}/ZnS nanotubes were investigated by scanning electron microscopy, transmission electron microscopy and X-ray diffraction techniques. According to the results of fluorescence spectroscopy, pure TiO{sub 2} nanotubes exhibited a high emission at 380 nm (3.26 eV), whereas TiO{sub 2}/ZnS exhibited an emission at 410 nm (3.02 eV). The TiO{sub 2}/ZnS nanotubes demonstrated good bio-imaging ability on sycamore cultured plant cells. The biocompatibility against mammalian cells (Chinese Hamster Ovarian Cells—CHO) suggesting that TiO{sub 2}/ZnS may also have suitable optical properties for use as biological markers in diagnostic medicine. The drug release characteristic of TiO{sub 2}/ZnS nanotubes was explored using 5-fluorouracil (5-FU), an anticancer drug used in photodynamic therapy. The results show that the TiO{sub 2}/ZnS nanotubes are a promising candidate for anticancer drug delivery systems. - Highlights: • TiO{sub 2}/ZnS nanotubes showed a redshift in fluorescence spectrum. • Cytotoxicity against mammalian cells revealed biocompatibility of the nanotubes. • TiO{sub 2}/ZnS proved an efficient delivery system for anti-tumor 5-fluorouracil.

Automation of column-based radiochemical separations. A comparison of fluidic, robotic, and hybrid architectures

Energy Technology Data Exchange (ETDEWEB)

Grate, J.W.; O' Hara, M.J.; Farawila, A.F.; Ozanich, R.M.; Owsley, S.L. [Pacific Northwest National Laboratory, Richland, WA (United States)

2011-07-01

Two automated systems have been developed to perform column-based radiochemical separation procedures. These new systems are compared with past fluidic column separation architectures, with emphasis on using disposable components so that no sample contacts any surface that any other sample has contacted, and setting up samples and columns in parallel for subsequent automated processing. In the first new approach, a general purpose liquid handling robot has been modified and programmed to perform anion exchange separations using 2 mL bed columns in 6 mL plastic disposable column bodies. In the second new approach, a fluidic system has been developed to deliver clean reagents through disposable manual valves to six disposable columns, with a mechanized fraction collector that positions one of four rows of six vials below the columns. The samples are delivered to each column via a manual 3-port disposable valve from disposable syringes. This second approach, a hybrid of fluidic and mechanized components, is a simpler more efficient approach for performing anion exchange procedures for the recovery and purification of plutonium from samples. The automation architectures described can also be adapted to column-based extraction chromatography separations. (orig.)

Optimum design of A fluidic micro-oscillator

International Nuclear Information System (INIS)

Noh, Yoojeong; Youn, Sungkie; Kim, Moonuhn

2002-01-01

A fluidic micro-oscillator is used to control a linear tool as generating an oscillating fluid jet at its two output ports. The linear tool is a linear actuator that transforms the fluidic energy into mechanical energy via a double acting piston placed in linear actuator housing. Together the two devices form a dynamic microsystem that can be used in medical application. In this paper, we intend to optimize the geometry of the fluidic micro-oscillator. A basic oscillator design is varied in terms of supply nozzle geometry, length of the feedback channels, wall angle, control port width and etc. It was found that characteristics parameters such as frequency, volume flow and output pressure depends strongly on above mentioned design parameters. According to above the observations, we can determine an object function and design variables. Since we eventually have to maximize force to drive and steer a cutting tool, the output pressure difference is chosen as an object function and nozzle width, feedback channel, control port width, distance between splitter and nozzle can be chosen as the design variables. As a result of such design optimization, we can obtain the maximum force. At this time we maximize the output pressure difference using shape optimization

Carbon nanotube based photocathodes

International Nuclear Information System (INIS)

Hudanski, Ludovic; Minoux, Eric; Schnell, Jean-Philippe; Xavier, Stephane; Pribat, Didier; Legagneux, Pierre; Gangloff, Laurent; Teo, Kenneth B K; Robertson, John; Milne, William I

2008-01-01

This paper describes a novel photocathode which is an array of vertically aligned multi-walled carbon nanotubes (MWCNTs), each MWCNT being associated with one p-i-n photodiode. Unlike conventional photocathodes, the functions of photon-electron conversion and subsequent electron emission are physically separated. Photon-electron conversion is achieved with p-i-n photodiodes and the electron emission occurs from the MWCNTs. The current modulation is highly efficient as it uses an optically controlled reconfiguration of the electric field at the MWCNT locations. Such devices are compatible with high frequency and very large bandwidth operation and could lead to their application in compact, light and efficient microwave amplifiers for satellite telecommunication. To demonstrate this new photocathode concept, we have fabricated the first carbon nanotube based photocathode using silicon p-i-n photodiodes and MWCNT bunches. Using a green laser, this photocathode delivers 0.5 mA with an internal quantum efficiency of 10% and an I ON /I OFF ratio of 30

Room temperature vortex fluidic synthesis of monodispersed amorphous proto-vaterite.

Science.gov (United States)

Peng, Wenhong; Chen, Xianjue; Zhu, Shenmin; Guo, Cuiping; Raston, Colin L

2014-10-11

Monodispersed particles of amorphous calcium carbonate (ACC) 90 to 200 nm in diameter are accessible at room temperature in ethylene glycol and water using a vortex fluidic device (VFD). The ACC material is stable for at least two weeks under ambient conditions.

Carbon nanotube transistor based high-frequency electronics

Science.gov (United States)

Schroter, Michael

At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

Focused Ion Beam Nanopatterning for Carbon Nanotube Ropes Based Sensor

Directory of Open Access Journals (Sweden)

Vera LA FERRARA

2007-11-01

Full Text Available Focused Ion Beam (FIB technology has been used to realize electrode patterns for contacting Single Walled Carbon Nanotubes (SWCNTs ropes for chemical gas sensor applications. Two types of transducers, based on a single rope and on bundles, have been realized starting from silicon/Si3N4 substrate. Electrical behaviour, at room temperature, in toxic gas environments, has been investigated and compared to evaluate contribution of a single rope based sensor respect to bundles one. For all the devices, upon exposure to NO2 and NH3, the conductance has been found to increase or decrease respectively. Conductance signal is stronger for sensor based on bundles, but it also evident that response time in NO2 is faster for device based on a single rope. FIB technology offers, then, the possibility to contact easily a single sensitive nanowire, as carbon nanotube rope.

Quasi-static analysis and control of planer and spatial bending fluidic actuator

OpenAIRE

Chang, Benjamin Che-Ming

2011-01-01

This work presents a novel silicone-based millimetre scale bending fluidic actuator. Two designs of the bending fluidic actuator are studied: a planer actuator that bends about one axis; and a spatial actuator able to bend about two orthogonal axes. The unique parallel micro-channel design of the fluidic actuators enables operation at low working pressures, while at the same time having a very limited thickness expansion during pressurization. The fluidic actuators can be easily scaled to des...

Hybrid macro-micro fluidics system for a chip-based biosensor

Science.gov (United States)

Tamanaha, C. R.; Whitman, L. J.; Colton, R. J.

2002-03-01

We describe the engineering of a hybrid fluidics platform for a chip-based biosensor system that combines high-performance microfluidics components with powerful, yet compact, millimeter-scale pump and valve actuators. The microfluidics system includes channels, valveless diffuser-based pumps, and pinch-valves that are cast into a poly(dimethylsiloxane) (PDMS) membrane and packaged along with the sensor chip into a palm-sized plastic cartridge. The microfluidics are driven by pump and valve actuators contained in an external unit (with a volume ~30 cm3) that interfaces kinematically with the PDMS microelements on the cartridge. The pump actuator is a simple-lever, flexure-hinge displacement amplifier that increases the motion of a piezoelectric stack. The valve actuators are an array of cantilevers operated by shape memory alloy wires. All components can be fabricated without the need for complex lithography or micromachining, and can be used with fluids containing micron-sized particulates. Prototypes have been modeled and tested to ensure the delivery of microliter volumes of fluid and the even dispersion of reagents over the chip sensing elements. With this hybrid approach to the fluidics system, the biochemical assay benefits from the many advantages of microfluidics yet we avoid the complexity and unknown reliability of immature microactuator technologies.

Fusion-bonded fluidic interconnects

NARCIS (Netherlands)

Fazal, I.; Elwenspoek, Michael Curt

2008-01-01

A new approach to realize fluidic interconnects based on the fusion bonding of glass tubes with silicon is presented. Fusion bond strength analyses have been carried out. Experiments with plain silicon wafers and coated with silicon oxide and silicon nitride are performed. The obtained results are

Durable transparent carbon nanotube films for flexible device components

International Nuclear Information System (INIS)

Sierros, K.A.; Hecht, D.S.; Banerjee, D.A.; Morris, N.J.; Hu, L.; Irvin, G.C.; Lee, R.S.; Cairns, D.R.

2010-01-01

This paper describes a durable carbon nanotube (CNT) film for flexible devices and its mechanical properties. Films as thin as 10 nm thick have properties approaching those of existing electrodes based on indium tin oxide (ITO) but with significantly improved mechanical properties. In uniaxial tension, strains as high as 25% are required for permanent damage and at lower strains resistance changes are slight and consistent with elastic deformation of the individual CNTs. A simple model confirms that changes in electrical resistance are described by a Poisson's ratio of 0.22. These films are also durable to cyclic loading, and even at peak strains of 10% no significant damage occurs after 250 cycles. The scratch resistance is also high as measured by nanoscratch, and for a 50 μm tip a load of 140 mN is required to cause initial failure. This is more than 5 times higher than is required to cause cracking in ITO. The robustness of the transparent conductive coating leads to significant improvement in device performance. In touch screen devices fabricated using CNT no failure occurs after a million actuations while for devices based on ITO electrodes 400,000 cycles are needed to cause failure. These durable electrodes hold the key to developing robust, large-area, lightweight, optoelectronic devices such as lighting, displays, electronic-paper, and printable solar cells. Such devices could hold the key to producing inexpensive green energy, providing reliable solid-state lighting, and significantly reducing our dependence on paper.

MEMS fluidic actuator

Science.gov (United States)

Kholwadwala, Deepesh K [Albuquerque, NM; Johnston, Gabriel A [Trophy Club, TX; Rohrer, Brandon R [Albuquerque, NM; Galambos, Paul C [Albuquerque, NM; Okandan, Murat [Albuquerque, NM

2007-07-24

The present invention comprises a novel, lightweight, massively parallel device comprising microelectromechanical (MEMS) fluidic actuators, to reconfigure the profile, of a surface. Each microfluidic actuator comprises an independent bladder that can act as both a sensor and an actuator. A MEMS sensor, and a MEMS valve within each microfluidic actuator, operate cooperatively to monitor the fluid within each bladder, and regulate the flow of the fluid entering and exiting each bladder. When adjacently spaced in a array, microfluidic actuators can create arbitrary surface profiles in response to a change in the operating environment of the surface. In an embodiment of the invention, the profile of an airfoil is controlled by independent extension and contraction of a plurality of actuators, that operate to displace a compliant cover.

Fabrication and Characterization of MWCNT-Based Bridge Devices

KAUST Repository

Chappanda, Karumbaiah N.

2017-08-21

Carbon nanotubes (CNTs) are one of the most actively researched structural materials due to their interesting electrical, mechanical, and chemical properties. Unlike single walled carbon nanotubes (SWCNTs), little work has been focused on multi-walled carbon nanotubes (MWCNTs) and their potential for practical devices. Here, we have fabricated bridge-shape devices integrating MWCNTs (> 50 nm in outer diameter) using three processes: optical lithography, electron beam-induced platinum deposition, and surface micromachining. Each device consists of a doubly-clamped nanotube suspended over gold electrodes on a highly conductive Si substrate. The suspended nanotubes are characterized individually using Raman spectroscopy and semiconductor parameters analysis and, overall, show, high crystallinity and low electrical resistance. The spring constants of doubly-clamped nanotubes were characterized using atomic force microscopy force-displacement measurements, with values as high as 70 N/m observed. Highly stiff MWCNTs are promising for a variety of applications, such as resonators and electrical interconnects. Through simulations, we estimate the resonance frequencies and pull-in voltages of these suspended nano-structures. The dependence of key parameters, such as the nanotube\\'s length, Young\\'s modulus, axial stress, and wall thickness is also discussed.

Heat Dissipation for Microprocessor Using Multiwalled Carbon Nanotubes Based Liquid

OpenAIRE

Hung Thang, Bui; Trinh, Pham Van; Chuc, Nguyen Van; Khoi, Phan Hong; Minh, Phan Ngoc

2013-01-01

Carbon nanotubes (CNTs) are one of the most valuable materials with high thermal conductivity (2000 W/m · K compared with thermal conductivity of Ag 419 W/m · K). This suggested an approach in applying the CNTs in thermal dissipation system for high power electronic devices, such as computer processor and high brightness light emitting diode (HB-LED). In this work, multiwalled carbon nanotubes (MWCNTs) based liquid was made by COOH functionalized MWCNTs dispersed in distilled water with conce...

Fabrication of spintronics device by direct synthesis of single-walled carbon nanotubes from ferromagnetic electrodes

Directory of Open Access Journals (Sweden)

Mohd Ambri Mohamed, Nobuhito Inami, Eiji Shikoh, Yoshiyuki Yamamoto, Hidenobu Hori and Akihiko Fujiwara

2008-01-01

Full Text Available We describe an alternative method for realizing a carbon nanotube spin field-effect transistor device by the direct synthesis of single-walled carbon nanotubes (SWNTs on substrates by alcohol catalytic chemical vapor deposition. We observed hysteretic magnetoresistance (MR at low temperatures due to spin-dependent transport. In these devices, the maximum ratio in resistance variation of MR was found to be 1.8%.

Imperceptible and Ultraflexible p-Type Transistors and Macroelectronics Based on Carbon Nanotubes.

Science.gov (United States)

Cao, Xuan; Cao, Yu; Zhou, Chongwu

2016-01-26

Flexible thin-film transistors based on semiconducting single-wall carbon nanotubes are promising for flexible digital circuits, artificial skins, radio frequency devices, active-matrix-based displays, and sensors due to the outstanding electrical properties and intrinsic mechanical strength of carbon nanotubes. Nevertheless, previous research effort only led to nanotube thin-film transistors with the smallest bending radius down to 1 mm. In this paper, we have realized the full potential of carbon nanotubes by making ultraflexible and imperceptible p-type transistors and circuits with a bending radius down to 40 μm. In addition, the resulted transistors show mobility up to 12.04 cm(2) V(-1) S(-1), high on-off ratio (∼10(6)), ultralight weight (transistors and circuits have great potential to work as indispensable components for ultraflexible complementary electronics.

Bolometric-Effect-Based Wavelength-Selective Photodetectors Using Sorted Single Chirality Carbon Nanotubes

Science.gov (United States)

Zhang, Suoming; Cai, Le; Wang, Tongyu; Shi, Rongmei; Miao, Jinshui; Wei, Li; Chen, Yuan; Sepúlveda, Nelson; Wang, Chuan

2015-01-01

This paper exploits the chirality-dependent optical properties of single-wall carbon nanotubes for applications in wavelength-selective photodetectors. We demonstrate that thin-film transistors made with networks of carbon nanotubes work effectively as light sensors under laser illumination. Such photoresponse was attributed to photothermal effect instead of photogenerated carriers and the conclusion is further supported by temperature measurements. Additionally, by using different types of carbon nanotubes, including a single chirality (9,8) nanotube, the devices exhibit wavelength-selective response, which coincides well with the absorption spectra of the corresponding carbon nanotubes. This is one of the first reports of controllable and wavelength-selective bolometric photoresponse in macroscale assemblies of chirality-sorted carbon nanotubes. The results presented here provide a viable route for achieving bolometric-effect-based photodetectors with programmable response spanning from visible to near-infrared by using carbon nanotubes with pre-selected chiralities. PMID:26643777

An Oxidase-Based Electrochemical Fluidic Sensor with High-Sensitivity and Low-Interference by On-Chip Oxygen Manipulation

Directory of Open Access Journals (Sweden)

Chang-Soo Kim

2012-06-01

Full Text Available Utilizing a simple fluidic structure, we demonstrate the improved performance of oxidase-based enzymatic biosensors. Electrolysis of water is utilized to generate bubbles to manipulate the oxygen microenvironment close to the biosensor in a fluidic channel. For the proper enzyme reactions to occur, a simple mechanical procedure of manipulating bubbles was developed to maximize the oxygen level while minimizing the pH change after electrolysis. The sensors show improved sensitivities based on the oxygen dependency of enzyme reaction. In addition, this oxygen-rich operation minimizes the ratio of electrochemical interference signal by ascorbic acid during sensor operation (i.e., amperometric detection of hydrogen peroxide. Although creatinine sensors have been used as the model system in this study, this method is applicable to many other biosensors that can use oxidase enzymes (e.g., glucose, alcohol, phenol, etc. to implement a viable component for in-line fluidic sensor systems.

Torsional carbon nanotube artificial muscles.

Science.gov (United States)

Foroughi, Javad; Spinks, Geoffrey M; Wallace, Gordon G; Oh, Jiyoung; Kozlov, Mikhail E; Fang, Shaoli; Mirfakhrai, Tissaphern; Madden, John D W; Shin, Min Kyoon; Kim, Seon Jeong; Baughman, Ray H

2011-10-28

Rotary motors of conventional design can be rather complex and are therefore difficult to miniaturize; previous carbon nanotube artificial muscles provide contraction and bending, but not rotation. We show that an electrolyte-filled twist-spun carbon nanotube yarn, much thinner than a human hair, functions as a torsional artificial muscle in a simple three-electrode electrochemical system, providing a reversible 15,000° rotation and 590 revolutions per minute. A hydrostatic actuation mechanism, as seen in muscular hydrostats in nature, explains the simultaneous occurrence of lengthwise contraction and torsional rotation during the yarn volume increase caused by electrochemical double-layer charge injection. The use of a torsional yarn muscle as a mixer for a fluidic chip is demonstrated.

Bulk heterojunction organic photovoltaic based on polythiophene-polyelectrolyte carbon nanotube composites

Energy Technology Data Exchange (ETDEWEB)

Reyes-Reyes, M. [Instituto de Investigacion en Comunicacion Optica, Universidad Autonoma de San Luis Potosi, Alvaro Obregon 64, San Luis Potosi (Mexico); Lopez-Sandoval, R. [Advanced Materials Department, IPICYT, Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi 78216 (Mexico); Liu, J.; Carroll, D.L. [Center for Nanotechnology and Molecular Materials, Wake Forest University, Winston-Salem, NC (United States)

2007-09-22

It is shown that carbon nanotubes can be used to enhance carrier mobility for efficient removal of the charges in thin film polymer-conjugated/fullerene photovoltaic devices. The fabricated photovoltaic devices consist of poly(3-octylthiophene) (P3OT) polymer blended with undoped multiwalled carbon nanotubes (MWNTs) and carbon nanotubes doped with nitrogen (CNx-MWNTs). Nanophase formation and dispersion problems associated with the use of carbon nanotubes in polymer devices were addressed through the generation of functional groups and electrostatic attaching of the polyelectrolyte poly(dimethyldiallylamine) chloride (PDDA) in both MWNTs and CNx-MWNT systems. The resultant nanophase was highly dispersed allowing for excellent bulk heterojunction formation. Our results indicate that CNx-MWNTs enhance the efficiency of P3OT solar cells in comparison with MWNTs. (author)

Variable recruitment fluidic artificial muscles: modeling and experiments

International Nuclear Information System (INIS)

Bryant, Matthew; Meller, Michael A; Garcia, Ephrahim

2014-01-01

We investigate taking advantage of the lightweight, compliant nature of fluidic artificial muscles to create variable recruitment actuators in the form of artificial muscle bundles. Several actuator elements at different diameter scales are packaged to act as a single actuator device. The actuator elements of the bundle can be connected to the fluidic control circuit so that different groups of actuator elements, much like individual muscle fibers, can be activated independently depending on the required force output and motion. This novel actuation concept allows us to save energy by effectively impedance matching the active size of the actuators on the fly based on the instantaneous required load. This design also allows a single bundled actuator to operate in substantially different force regimes, which could be valuable for robots that need to perform a wide variety of tasks and interact safely with humans. This paper proposes, models and analyzes the actuation efficiency of this actuator concept. The analysis shows that variable recruitment operation can create an actuator that reduces throttling valve losses to operate more efficiently over a broader range of its force–strain operating space. We also present preliminary results of the design, fabrication and experimental characterization of three such bioinspired variable recruitment actuator prototypes. (paper)

Neuromorphic function learning with carbon nanotube based synapses

International Nuclear Information System (INIS)

Gacem, Karim; Filoramo, Arianna; Derycke, Vincent; Retrouvey, Jean-Marie; Chabi, Djaafar; Zhao, Weisheng; Klein, Jacques-Olivier

2013-01-01

The principle of using nanoscale memory devices as artificial synapses in neuromorphic circuits is recognized as a promising way to build ground-breaking circuit architectures tolerant to defects and variability. Yet, actual experimental demonstrations of the neural network type of circuits based on non-conventional/non-CMOS memory devices and displaying function learning capabilities remain very scarce. We show here that carbon-nanotube-based memory elements can be used as artificial synapses, combined with conventional neurons and trained to perform functions through the application of a supervised learning algorithm. The same ensemble of eight devices can notably be trained multiple times to code successively any three-input linearly separable Boolean logic function despite device-to-device variability. This work thus represents one of the very few demonstrations of actual function learning with synapses based on nanoscale building blocks. The potential of such an approach for the parallel learning of multiple and more complex functions is also evaluated. (paper)

LES-based characterization of a suction and oscillatory blowing fluidic actuator

Science.gov (United States)

Kim, Jeonglae; Moin, Parviz

2015-11-01

Recently, a novel fluidic actuator using steady suction and oscillatory blowing was developed for control of turbulent flows. The suction and oscillatory blowing (SaOB) actuator combines steady suction and pulsed oscillatory blowing into a single device. The actuation is based upon a self-sustained mechanism of confined jets and does not require any moving parts. The control output is determined by a pressure source and the geometric details, and no additional input is needed. While its basic mechanisms have been investigated to some extent, detailed characteristics of internal turbulent flows are not well understood. In this study, internal flows of the SaOB actuator are simulated using large-eddy simulation (LES). Flow characteristics within the actuator are described in detail for a better understanding of the physical mechanisms and improving the actuator design. LES predicts the self-sustained oscillations of the turbulent jet. Switching frequency, maximum velocity at the actuator outlets, and wall pressure distribution are in good agreement with the experimental measurements. The computational results are used to develop simplified boundary conditions for numerical experiments of active flow control. Supported by the Boeing company.

Fabrication and Characterization of MWCNT-Based Bridge Devices

KAUST Repository

Chappanda, Karumbaiah N.; Batra, Nitin M; Holguin, Jorge; Da Costa, Pedro M. F. J.; Younis, Mohammad I.

2017-01-01

Carbon nanotubes (CNTs) are one of the most actively researched structural materials due to their interesting electrical, mechanical, and chemical properties. Unlike single walled carbon nanotubes (SWCNTs), little work has been focused on multi-walled carbon nanotubes (MWCNTs) and their potential for practical devices. Here, we have fabricated bridge-shape devices integrating MWCNTs (> 50 nm in outer diameter) using three processes: optical lithography, electron beam-induced platinum deposition, and surface micromachining. Each device consists of a doubly-clamped nanotube suspended over gold electrodes on a highly conductive Si substrate. The suspended nanotubes are characterized individually using Raman spectroscopy and semiconductor parameters analysis and, overall, show, high crystallinity and low electrical resistance. The spring constants of doubly-clamped nanotubes were characterized using atomic force microscopy force-displacement measurements, with values as high as 70 N/m observed. Highly stiff MWCNTs are promising for a variety of applications, such as resonators and electrical interconnects. Through simulations, we estimate the resonance frequencies and pull-in voltages of these suspended nano-structures. The dependence of key parameters, such as the nanotube's length, Young's modulus, axial stress, and wall thickness is also discussed.

Carbon nanotube junctions and devices

NARCIS (Netherlands)

Postma, H.W.Ch.

2001-01-01

In this thesis Postma presents transport experiments performed on individual single-wall carbon nanotubes. Carbon nanotubes are molecules entirely made of carbon atoms. The electronic properties are determined by the exact symmetry of the nanotube lattice, resulting in either metallic or

Facile Preparation of Carbon-Nanotube-based 3-Dimensional Transparent Conducting Networks for Flexible Noncontact Sensing Device

KAUST Repository

Tai, Yanlong

2016-04-12

Here, we report the controllable fabrication of transparent conductive films (TCFs) for moisture-sensing applications based on heating-rate-triggered, 3-dimensional porous conducting networks of single-walled carbon nanotube (SWCNT)/poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS). How baking conditions influence the self-assembled microstructure of the TCFs is discussed. The sensor presents high-performance properties, including a reasonable sheet resistance (2.1 kohm/sq), a high visible-range transmittance (> 69 %, PET = 90 %), and good stability when subjected to cyclic loading (> 1000 cycles, better than indium tin oxide film) during processing. Moreover, the benefits of these kinds of TCFs were verified through a fully transparent, highly sensitive, rapid response, noncontact moisture-sensing device (5×5 sensing pixels).

Fabrication and characterization of a carbon nanotube-based nanoknife

International Nuclear Information System (INIS)

Singh, G; Rice, P; Mahajan, R L; McIntosh, J R

2009-01-01

We demonstrate the fabrication and testing of a prototype microtome knife based on a multiwalled carbon nanotube (MWCNT) for cutting ∼100 nm thick slices of frozen-hydrated biological samples. A piezoelectric-based 3D manipulator was used inside a scanning electron microscope (SEM) to select and position individual MWCNTs, which were subsequently welded in place using electron beam-induced deposition. The knife is built on a pair of tungsten needles with provision to adjust the distance between the needle tips, accommodating various lengths of MWCNTs. We performed experiments to test the mechanical strength of a MWCNT in the completed device using an atomic force microscope tip. An increasing force was applied at the mid-point of the nanotube until failure occurred, which was observed in situ in the SEM. The maximum breaking force was approximately (8 x 10 -7 ) N which corresponds well with the typical microtome cutting forces reported in the literature. In situ cutting experiments were performed on a cell biological embedding plastic (epoxy) by pushing it against the nanotube. Initial experiments show indentation marks on the epoxy surface. Quantitative analysis is currently limited by the surface asperities, which have the same dimensions as the nanotube.

Peptide aptamer-assisted immobilization of green fluorescent protein for creating biomolecule-complexed carbon nanotube device

Science.gov (United States)

Nii, Daisuke; Nozawa, Yosuke; Miyachi, Mariko; Yamanoi, Yoshinori; Nishihara, Hiroshi; Tomo, Tatsuya; Shimada, Yuichiro

2017-10-01

Carbon nanotubes are a novel material for next-generation applications. In this study, we generated carbon nanotube and green fluorescent protein (GFP) conjugates using affinity binding peptides. The carbon nanotube-binding motif was introduced into the N-terminus of the GFP through molecular biology methods. Multiple GFPs were successfully aligned on a single-walled carbon nanotube via the molecular recognition function of the peptide aptamer, which was confirmed through transmission electron microscopy and optical analysis. Fluorescence spectral analysis results also suggested that the carbon nanotube-GFP complex was autonomously formed with orientation and without causing protein denaturation during immobilization. This simple process has a widespread potential for fabricating carbon nanotube-biomolecule hybrid devices.

Nanotube phonon waveguide

Science.gov (United States)

Chang, Chih-Wei; Zettl, Alexander K.

2013-10-29

Disclosed are methods and devices in which certain types of nanotubes (e.g., carbon nanotubes and boron nitride nanotubes conduct heat with high efficiency and are therefore useful in electronic-type devices.

Dual sensing-actuation artificial muscle based on polypyrrole-carbon nanotube composite

Science.gov (United States)

Schumacher, J.; Otero, Toribio F.; Pascual, Victor H.

2017-04-01

Dual sensing artificial muscles based on conducting polymer are faradaic motors driven by electrochemical reactions, which announce the development of proprioceptive devices. The applicability of different composites has been investigated with the aim to improve the performance. Addition of carbon nanotubes may reduce irreversible reactions. We present the testing of a dual sensing artificial muscle based on a conducting polymer and carbon nanotubes composite. Large bending motions (up to 127 degrees) in aqueous solution and simultaneously sensing abilities of the operation conditions are recorded. The sensing and actuation equations are derived for incorporation into a control system.

A Single-Walled Carbon Nanotube Network Gas Sensing Device

Directory of Open Access Journals (Sweden)

I-Ju Teng

2011-08-01

Full Text Available The goal of this research was to develop a chemical gas sensing device based on single-walled carbon nanotube (SWCNT networks. The SWCNT networks are synthesized on Al2O3-deposted SiO2/Si substrates with 10 nm-thick Fe as the catalyst precursor layer using microwave plasma chemical vapor deposition (MPCVD. The development of interconnected SWCNT networks can be exploited to recognize the identities of different chemical gases by the strength of their particular surface adsorptive and desorptive responses to various types of chemical vapors. The physical responses on the surface of the SWCNT networks cause superficial changes in the electric charge that can be converted into electronic signals for identification. In this study, we tested NO2 and NH3 vapors at ppm levels at room temperature with our self-made gas sensing device, which was able to obtain responses to sensitivity changes with a concentration of 10 ppm for NO2 and 24 ppm for NH3.

Accelerated reliability testing of highly aligned single-walled carbon nanotube networks subjected to DC electrical stressing.

Science.gov (United States)

Strus, Mark C; Chiaramonti, Ann N; Kim, Young Lae; Jung, Yung Joon; Keller, Robert R

2011-07-01

We investigate the electrical reliability of nanoscale lines of highly aligned, networked, metallic/semiconducting single-walled carbon nanotubes (SWCNTs) fabricated through a template-based fluidic assembly process. We find that these SWCNT networks can withstand DC current densities larger than 10 MA cm(-2) for several hours and, in some cases, several days. We develop test methods that show that the degradation rate, failure predictability and total device lifetime can be linked to the initial resistance. Scanning electron and transmission electron microscopy suggest that fabrication variability plays a critical role in the rate of degradation, and we offer an empirical method of quickly determining the long-term performance of a network. We find that well-fabricated lines subject to constant electrical stress show a linear accumulation of damage reminiscent of electromigration in metallic interconnects, and we explore the underlying physical mechanisms that could cause such behavior.

A fluidic device for the controlled formation and real-time monitoring of soft membranes self-assembled at liquid interfaces.

Science.gov (United States)

Mendoza-Meinhardt, Arturo; Botto, Lorenzo; Mata, Alvaro

2018-02-13

Membrane materials formed at the interface between two liquids have found applications in a large variety of technologies, from sensors to drug-delivery and catalysis. However, studying the formation of these membranes in real-time presents considerable challenges, owing to the difficulty of prescribing the location and instant of formation of the membrane, the difficulty of observing time-dependent membrane shape and thickness, and the poor reproducibility of results obtained using conventional mixing procedures. Here we report a fluidic device that facilitates characterisation of the time-dependent thickness, morphology and mass transport properties of materials self-assembled at fluid-fluid interfaces. In the proposed device the membrane forms from the controlled coalescence of two liquid menisci in a linear open channel. The linear geometry and controlled mixing of the solutions facilitate real-time visualisation, manipulation and improve reproducibility. Because of its small dimensions, the device can be used in conjunction with standard microscopy methods and reduces the required volumes of potentially expensive reagents. As an example application to tissue engineering, we use the device to characterise interfacial membranes formed by supra-molecular self-assembly of peptide-amphiphiles with either an elastin-like-protein or hyaluronic acid. The device can be adapted to study self-assembling membranes for applications that extend beyond bioengineering.

Effects of junctions on carbon nanotube network-based devices

Energy Technology Data Exchange (ETDEWEB)

Kang, Pil Soo; Kim, Gyu Tae [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

2011-11-15

Realistic random networks of carbon nanotubes (CNTs) were simulated by the noble hybrid method combining Monte Carlo and SPICE simulations. Near the percolation threshold, the electrical characteristics of networks are strongly affected by the contacts among nanotubes. The nonlinear electrical junctions in the CNT network were modeled by suitable SPICE models and simulated using our hybrid simulation method. We successfully described the morphological percolation threshold, and the critical density was determined as a function of normalized length. The effects of electrical junctions on the scaling of the sheet conductance were investigated. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

Science.gov (United States)

Martinez, Amos; Al Araimi, Mohammed; Dmitriev, Artemiy; Lutsyk, Petro; Li, Shen; Mou, Chengbo; Rozhin, Alexey; Sumetsky, Misha; Turitsyn, Sergei

2017-12-01

The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors) and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50%) and poor saturable to non-saturable absorption ratios (typically above 1:5). In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%), and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

Performance improvement induced by asymmetric Y2O3-coated device structure to carbon-nanotube-film based photodetectors

Science.gov (United States)

Wang, Fanglin; Xu, Haitao; Huang, Huixin; Ma, Ze; Wang, Sheng; Peng, Lian-Mao

2017-11-01

Film-based semiconducting carbon nanotube (CNT) photodetectors are promising candidates for industrial applications. However, unintentional doping from the environment such as water/oxygen (H2O/O2) redox, polymers, etc. changes the doping level of the CNT film. Here, we evaluate the performance of film-based barrier-free bipolar diodes (BFBDs), which are basically semiconducting CNT films asymmetrically contacted by perfect n-type ohmic contact (scandium, Sc) and p-type ohmic contact (palladium, Pd) at the two ends of the diode. We show that normal BFBD devices have large variances of forward current, reverse current, and photocurrent for different doping levels of the channel. We propose an asymmetric Y2O3-coated BFBD device in which the channel is covered by a layer of an Y2O3 film and an overlap between the Sc electrode and the Y2O3 film is designed. The Y2O3 film provides p-type doping to the channel. The overlap section increases the length of the base of the pn junction, and the diffusion current of holes is suppressed. In this way, the rectifier factors (current ratio when voltages are at +0.5 V and -0.5 V) of the asymmetric Y2O3-coated BFBD devices are around two orders of magnitude larger and the photocurrent generation is more stable compared to that of normal devices. Our results provide a way to conquer the influence of unintentional doping from the environment and suppress reverse current in pn diodes. This is beneficial to applications of CNT-based photodetectors and of importance for inspiring methods to improve the performances of devices based on other low dimensional materials.

Non-invasive paper-based microfluidic device for ultra-low detection of urea through enzyme catalysis

Science.gov (United States)

Suresh, Vignesh; Qunya, Ong; Kanta, Bera Lakshmi; Yuh, Lee Yeong; Chong, Karen S. L.

2018-03-01

This work describes the design, fabrication and characterization of a paper-based microfluidic device for ultra-low detection of urea through enzyme catalysis. The microfluidic system comprises an entry port, a fluidic channel, a reaction zone and two electrodes (contacts). Wax printing was used to create fluidic channels on the surface of a chromatography paper. Pre-conceptualized designs of the fluidic channel are wax-printed on the paper substrate while the electrodes are screen-printed. The paper printed with wax is heated to cause the wax reflow along the thickness of the paper that selectively creates hydrophilic and hydrophobic zones inside the paper. Urease immobilized in the reaction zone catalyses urea into releasing ions and, thereby, generating a current flow between the electrodes. A measure of current with respect to time at a fixed potential enables the detection of urea. The methodology enabled urea concentration down to 1 pM to be detected. The significance of this work lies in the use of simple and inexpensive paper-based substrates to achieve detection of ultra-low concentrations of analytes such as urea. The process is non-invasive and employs a less cumbersome two-electrode assembly.

Pressure driven digital logic in PDMS based microfluidic devices fabricated by multilayer soft lithography.

Science.gov (United States)

Devaraju, Naga Sai Gopi K; Unger, Marc A

2012-11-21

Advances in microfluidics now allow an unprecedented level of parallelization and integration of biochemical reactions. However, one challenge still faced by the field has been the complexity and cost of the control hardware: one external pressure signal has been required for each independently actuated set of valves on chip. Using a simple post-modification to the multilayer soft lithography fabrication process, we present a new implementation of digital fluidic logic fully analogous to electronic logic with significant performance advances over the previous implementations. We demonstrate a novel normally closed static gain valve capable of modulating pressure signals in a fashion analogous to an electronic transistor. We utilize these valves to build complex fluidic logic circuits capable of arbitrary control of flows by processing binary input signals (pressure (1) and atmosphere (0)). We demonstrate logic gates and devices including NOT, NAND and NOR gates, bi-stable flip-flops, gated flip-flops (latches), oscillators, self-driven peristaltic pumps, delay flip-flops, and a 12-bit shift register built using static gain valves. This fluidic logic shows cascade-ability, feedback, programmability, bi-stability, and autonomous control capability. This implementation of fluidic logic yields significantly smaller devices, higher clock rates, simple designs, easy fabrication, and integration into MSL microfluidics.

AC-conductance and capacitance measurements for ethanol vapor detection using carbon nanotube-polyvinyl alcohol composite based devices.

Science.gov (United States)

Greenshields, Márcia W C C; Meruvia, Michelle S; Hümmelgen, Ivo A; Coville, Neil J; Mhlanga, Sabelo D; Ceragioli, Helder J; Quispe, Jose C Rojas; Baranauskas, Vitor

2011-03-01

We report the preparation of inexpensive ethanol sensor devices using multiwalled carbon nanotube-polyvinyl alcohol composite films deposited onto interdigitated electrodes patterned on phenolite substrates. We investigate the frequency dependent response of the device conductance and capacitance showing that higher sensitivity is obtained at higher frequency if the conductance is used as sensing parameter. In the case of capacitance measurements, higher sensitivity is obtained at low frequency. Ethanol detection at a concentration of 300 ppm in air is demonstrated. More than 80% of the sensor conductance and capacitance variation response occurs in less than 20 s.

On Emulation of Flueric Devices in Excitable Chemical Medium.

Science.gov (United States)

Adamatzky, Andrew

2016-01-01

Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ) medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, and, xor, not and nor Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies.

On Emulation of Flueric Devices in Excitable Chemical Medium.

Directory of Open Access Journals (Sweden)

Andrew Adamatzky

Full Text Available Flueric devices are fluidic devices without moving parts. Fluidic devices use fluid as a medium for information transfer and computation. A Belousov-Zhabotinsky (BZ medium is a thin-layer spatially extended excitable chemical medium which exhibits travelling excitation wave-fronts. The excitation wave-fronts transfer information. Flueric devices compute via jets interaction. BZ devices compute via excitation wave-fronts interaction. In numerical model of BZ medium we show that functions of key flueric devices are implemented in the excitable chemical system: signal generator, and, xor, not and nor Boolean gates, delay elements, diodes and sensors. Flueric devices have been widely used in industry since late 1960s and are still employed in automotive and aircraft technologies. Implementation of analog of the flueric devices in the excitable chemical systems opens doors to further applications of excitation wave-based unconventional computing in soft robotics, embedded organic electronics and living technologies.

Methodology for designing and manufacturing complex biologically inspired soft robotic fluidic actuators: prosthetic hand case study.

Science.gov (United States)

Thompson-Bean, E; Das, R; McDaid, A

2016-10-31

We present a novel methodology for the design and manufacture of complex biologically inspired soft robotic fluidic actuators. The methodology is applied to the design and manufacture of a prosthetic for the hand. Real human hands are scanned to produce a 3D model of a finger, and pneumatic networks are implemented within it to produce a biomimetic bending motion. The finger is then partitioned into material sections, and a genetic algorithm based optimization, using finite element analysis, is employed to discover the optimal material for each section. This is based on two biomimetic performance criteria. Two sets of optimizations using two material sets are performed. Promising optimized material arrangements are fabricated using two techniques to validate the optimization routine, and the fabricated and simulated results are compared. We find that the optimization is successful in producing biomimetic soft robotic fingers and that fabrication of the fingers is possible. Limitations and paths for development are discussed. This methodology can be applied for other fluidic soft robotic devices.

Comparison of cumulative dissipated energy delivered by active-fluidic pressure control phacoemulsification system versus gravity-fluidics.

Science.gov (United States)

Gonzalez-Salinas, Roberto; Garza-Leon, Manuel; Saenz-de-Viteri, Manuel; Solis-S, Juan C; Gulias-Cañizo, Rosario; Quiroz-Mercado, Hugo

2017-08-22

To compare the cumulative dissipated energy (CDE), aspiration time and estimated aspiration fluid utilized during phacoemulsification cataract surgery using two phacoemulsification systems . A total of 164 consecutive eyes of 164 patients undergoing cataract surgery, 82 in the active-fluidics group and 82 in the gravity-fluidics group were enrolled in this study. Cataracts graded NII to NIII using LOCS II were included. Each subject was randomly assigned to one of the two platforms with a specific configuration: the active-fluidics Centurion ® phacoemulsification system or the gravity-fluidics Infiniti ® Vision System. CDE, aspiration time (AT) and the mean estimated aspiration fluid (EAF) were registered and compared. A mean age of 68.3 ± 9.8 years was found (range 57-92 years), and no significant difference was evident between both groups. A positive correlation between the CDE values obtained by both platforms was verified (r = 0.271, R 2  = 0.073, P = 0.013). Similarly, a significant correlation was evidenced for the EAF (r = 0.334, R 2  = 0.112, P = 0.046) and AT values (r = 0.156, R 2  = 0.024, P = 0.161). A statistically significantly lower CDE count, aspiration time and estimated fluid were obtained using the active-fluidics configuration when compared to the gravity-fluidics configuration by 19.29, 12.10 and 9.29%, respectively (P = 0.001, P Infiniti ® IP system for NII and NIII cataracts.

Solid-state, polymer-based fiber solar cells with carbon nanotube electrodes.

Science.gov (United States)

Liu, Dianyi; Zhao, Mingyan; Li, Yan; Bian, Zuqiang; Zhang, Luhui; Shang, Yuanyuan; Xia, Xinyuan; Zhang, Sen; Yun, Daqin; Liu, Zhiwei; Cao, Anyuan; Huang, Chunhui

2012-12-21

Most previous fiber-shaped solar cells were based on photoelectrochemical systems involving liquid electrolytes, which had issues such as device encapsulation and stability. Here, we deposited classical semiconducting polymer-based bulk heterojunction layers onto stainless steel wires to form primary electrodes and adopted carbon nanotube thin films or densified yarns to replace conventional metal counter electrodes. The polymer-based fiber cells with nanotube film or yarn electrodes showed power conversion efficiencies in the range 1.4% to 2.3%, with stable performance upon rotation and large-angle bending and during long-time storage without further encapsulation. Our fiber solar cells consisting of a polymeric active layer sandwiched between steel and carbon electrodes have potential in the manufacturing of low-cost, liquid-free, and flexible fiber-based photovoltaics.

Integrated optics nano-opto-fluidic sensor based on whispering gallery modes for picoliter volume refractometry

NARCIS (Netherlands)

Gilardi, G.; Beccherelli, R.

2013-01-01

We propose and numerically investigate an integrated optics refractometric nano-opto-fluidic sensor based on whispering gallery modes in sapphire microspheres. A measurand fluid is injected in a micromachined reservoir defined in between the microsphere and an optical waveguide. The wavelength shift

Fluidic system for long-term in vitro culturing and monitoring of organotypic brain slices

DEFF Research Database (Denmark)

Bakmand, Tanya; Troels-Smith, Ane R.; Dimaki, Maria

2015-01-01

Brain slice preparations cultured in vitro have long been used as a simplified model for studying brain development, electrophysiology, neurodegeneration and neuroprotection. In this paper an open fluidic system developed for improved long term culturing of organotypic brain slices is presented....... The positive effect of continuous flow of growth medium, and thus stability of the glucose concentration and waste removal, is simulated and compared to the effect of stagnant medium that is most often used in tissue culturing. Furthermore, placement of the tissue slices in the developed device was studied...... by numerical simulations in order to optimize the nutrient distribution. The device was tested by culturing transverse hippocampal slices from 7 days old NMRI mice for a duration of 14 days. The slices were inspected visually and the slices cultured in the fluidic system appeared to have preserved...

Packaged integrated opto-fluidic solution for harmful fluid analysis

Science.gov (United States)

Allenet, T.; Bucci, D.; Geoffray, F.; Canto, F.; Couston, L.; Jardinier, E.; Broquin, J.-E.

2016-02-01

Advances in nuclear fuel reprocessing have led to a surging need for novel chemical analysis tools. In this paper, we present a packaged lab-on-chip approach with co-integration of optical and micro-fluidic functions on a glass substrate as a solution. A chip was built and packaged to obtain light/fluid interaction in order for the entire device to make spectral measurements using the photo spectroscopy absorption principle. The interaction between the analyte solution and light takes place at the boundary between a waveguide and a fluid micro-channel thanks to the evanescent part of the waveguide's guided mode that propagates into the fluid. The waveguide was obtained via ion exchange on a glass wafer. The input and the output of the waveguides were pigtailed with standard single mode optical fibers. The micro-scale fluid channel was elaborated with a lithography procedure and hydrofluoric acid wet etching resulting in a 150+/-8 μm deep channel. The channel was designed with fluidic accesses, in order for the chip to be compatible with commercial fluidic interfaces/chip mounts. This allows for analyte fluid in external capillaries to be pumped into the device through micro-pipes, hence resulting in a fully packaged chip. In order to produce this co-integrated structure, two substrates were bonded. A study of direct glass wafer-to-wafer molecular bonding was carried-out to improve detector sturdiness and durability and put forward a bonding protocol with a bonding surface energy of γ>2.0 J.m-2. Detector viability was shown by obtaining optical mode measurements and detecting traces of 1.2 M neodymium (Nd) solute in 12+/-1 μL of 0.01 M and pH 2 nitric acid (HNO3) solvent by obtaining an absorption peak specific to neodymium at 795 nm.

Low-loss saturable absorbers based on tapered fibers embedded in carbon nanotube/polymer composites

Directory of Open Access Journals (Sweden)

Amos Martinez

2017-12-01

Full Text Available The emergence of low-dimensional materials has opened new opportunities in the fabrication of compact nonlinear photonic devices. Single-walled carbon nanotubes were among the first of those materials to attract the attention of the photonics community owing to their high third order susceptibility, broadband operation, and ultrafast response. Saturable absorption, in particular, has become a widespread application for nanotubes in the mode-locking of a fiber laser where they are used as nonlinear passive amplitude modulators to initiate pulsed operation. Numerous approaches have been proposed for the integration of nanotubes in fiber systems; these can be divided into those that rely on direct interaction (where the nanotubes are sandwiched between fiber connectors and those that rely on lateral interaction with the evanescence field of the propagating wave. Tapered fibers, in particular, offer excellent flexibility to adjust the nonlinearity of nanotube-based devices but suffer from high losses (typically exceeding 50% and poor saturable to non-saturable absorption ratios (typically above 1:5. In this paper, we propose a method to fabricate carbon nanotube saturable absorbers with controllable saturation power, low-losses (as low as 15%, and large saturable to non-saturable loss ratios approaching 1:1. This is achieved by optimizing the procedure of embedding tapered fibers in low-refractive index polymers. In addition, this study sheds light in the operation of these devices, highlighting a trade-off between losses and saturation power and providing guidelines for the design of saturable absorbers according to their application.

Carbon nanotube based 3-D matrix for enabling three-dimensional nano-magneto-electronics [corrected].

Directory of Open Access Journals (Sweden)

Jeongmin Hong

Full Text Available This letter describes the use of vertically aligned carbon nanotubes (CNT-based arrays with estimated 2-nm thick cobalt (Co nanoparticles deposited inside individual tubes to unravel the possibility of using the unique templates for ultra-high-density low-energy 3-D nano-magneto-electronic devices. The presence of oriented 2-nm thick Co layers within individual nanotubes in the CNT-based 3-D matrix is confirmed through VSM measurements as well as an energy-dispersive X-ray spectroscopy (EDS.

Controllable nanoscale rotating actuator system based on carbon nanotube and graphene

International Nuclear Information System (INIS)

Huang, Jianzhang; Han, Qiang

2016-01-01

A controllable nanoscale rotating actuator system consisting of a double carbon nanotube and graphene driven by a temperature gradient is proposed, and its rotating dynamics performance and driving mechanism are investigated through molecular dynamics simulations. The outer tube exhibits stable pure rotation with certain orientation under temperature gradient and the steady rotational speed rises as the temperature gradient increases. It reveals that the driving torque is caused by the difference of atomic van der Waals potentials due to the temperature gradient and geometrical features of carbon nanotube. A theoretical model for driving torque is established based on lattice dynamics theory and its predicted results agree well with molecular dynamics simulations. Further discussion is taken according to the theoretical model. The work in this study would be a guide for design and application of controllable nanoscale rotating devices based on carbon nanotubes and graphene. (paper)

Medium scale carbon nanotube thin film integrated circuits on flexible plastic substrates

Science.gov (United States)

Rogers, John A; Cao, Qing; Alam, Muhammad; Pimparkar, Ninad

2015-02-03

The present invention provides device components geometries and fabrication strategies for enhancing the electronic performance of electronic devices based on thin films of randomly oriented or partially aligned semiconducting nanotubes. In certain aspects, devices and methods of the present invention incorporate a patterned layer of randomly oriented or partially aligned carbon nanotubes, such as one or more interconnected SWNT networks, providing a semiconductor channel exhibiting improved electronic properties relative to conventional nanotubes-based electronic systems.

Growth of ZnO nanotube arrays and nanotube based piezoelectric nanogenerators

KAUST Repository

Xi, Yi; Song, Jinhui; Xu, Sheng; Yang, Rusen; Gao, Zhiyuan; Hu, Chenguo; Wang, Zhong Lin

2009-01-01

We present a systematic study of the growth of hexagonal ZnO nanotube arrays using a solution chemical method by varying the growth temperature (<100 °C), time and solution concentration. A piezoelectric nanogenerator using the as-grown ZnO nanotube arrays has been demonstrated for the first time. The nanogenerator gives an output voltage up to 35 mV. The detailed profile of the observed electric output is understood based on the calculated piezoelectric potential in the nanotube with consideration of the Schottky contact formed between the metal tip and the nanotube; and the mechanism agrees with that proposed for nanowire based nanogenerator. Our study shows that ZnO nanotubes can also be used for harvesting mechanical energy. © 2009 The Royal Society of Chemistry.

Recent advances in carbon nanotube-based electronics

International Nuclear Information System (INIS)

Sharma, Prithu; Ahuja, Prerit

2008-01-01

CNT-electronics is a field involving synthesis of carbon nanotubes-based novel electronic circuits, comparable to the size of molecules, the practically fundamental size possible. It has brought a new paradigm in science as it has enabled scientists to increase the device integration density tremendously, hence achieving better efficiency and speed. Here we review the state-of-art current research on the applications of CNTs in electronics and present recent results outlining their potential along with illustrating some current concerns in the research field. Unconventional projects such as CNT-based biological sensors, transistors, field emitters, integrated circuits, etc. are taking CNT-based electronics to its extremes. The field holds a promise for mass production of high speed and efficient electronic devices. However, the chemical complexity, reproducibility and other factors make the field a challenging one, which need to be addressed before the field realizes its true potential

Study of thermo-fluidic behavior of micro-droplet in inkjet-based micro manufacturing processes

Science.gov (United States)

Das, Raju; Mahapatra, Abhijit; Ball, Amit Kumar; Roy, Shibendu Shekhar; Murmu, Naresh Chandra

2017-06-01

Inkjet printing technology, a maskless, non-contact patterning operation, which has been a revelation in the field of micro and nano manufacturing for its use in the selective deposition of desired materials. It is becoming an exciting alternative technology such as lithography to print functional material on to a substrate. Selective deposition of functional materials on desired substrates is a basic requirement in many of the printing based micro and nano manufacturing operations like the fabrication of microelectronic devices, solar cell, Light-emitting Diode (LED) research fields like pharmaceutical industries for drug discovery purposes and in biotechnology to make DNA microarrays. In this paper, an attempt has been made to design and develop an indigenous Electrohydrodynamic Inkjet printing system for micro fabrication and to study the interrelationships between various thermos-fluidic parameters of the ink material in the printing process. The effect of printing process parameters on printing performance characteristics has also been studied. And the applicability of the process has also been experimentally demonstrated. The experimentally found results were quite satisfactory and accordance to its applicability.

Heat dissipation for the Intel Core i5 processor using multiwalled carbon-nanotube-based ethylene glycol

Energy Technology Data Exchange (ETDEWEB)

Thang, Bui Hung; Trinh, Pham Van; Quang, Le Dinh; Khoi, Phan Hong; Minh, Phan Ngoc [Vietnam Academy of Science and Technology, Ho Chi Minh CIty (Viet Nam); Huong, Nguyen Thi [Hanoi University of Science, Hanoi (Viet Nam); Vietnam National University, Hanoi (Viet Nam)

2014-08-15

Carbon nanotubes (CNTs) are some of the most valuable materials with high thermal conductivity. The thermal conductivity of individual multiwalled carbon nanotubes (MWCNTs) grown by using chemical vapor deposition is 600 ± 100 Wm{sup -1}K{sup -1} compared with the thermal conductivity 419 Wm{sup -1}K{sup -1} of Ag. Carbon-nanotube-based liquids - a new class of nanomaterials, have shown many interesting properties and distinctive features offering potential in heat dissipation applications for electronic devices, such as computer microprocessor, high power LED, etc. In this work, a multiwalled carbon-nanotube-based liquid was made of well-dispersed hydroxyl-functional multiwalled carbon nanotubes (MWCNT-OH) in ethylene glycol (EG)/distilled water (DW) solutions by using Tween-80 surfactant and an ultrasonication method. The concentration of MWCNT-OH in EG/DW solutions ranged from 0.1 to 1.2 gram/liter. The dispersion of the MWCNT-OH-based EG/DW solutions was evaluated by using a Zeta-Sizer analyzer. The MWCNT-OH-based EG/DW solutions were used as coolants in the liquid cooling system for the Intel Core i5 processor. The thermal dissipation efficiency and the thermal response of the system were evaluated by directly measuring the temperature of the micro-processor using the Core Temp software and the temperature sensors built inside the micro-processor. The results confirmed the advantages of CNTs in thermal dissipation systems for computer processors and other high-power electronic devices.

Heat dissipation for the Intel Core i5 processor using multiwalled carbon-nanotube-based ethylene glycol

International Nuclear Information System (INIS)

Thang, Bui Hung; Trinh, Pham Van; Quang, Le Dinh; Khoi, Phan Hong; Minh, Phan Ngoc; Huong, Nguyen Thi

2014-01-01

Carbon nanotubes (CNTs) are some of the most valuable materials with high thermal conductivity. The thermal conductivity of individual multiwalled carbon nanotubes (MWCNTs) grown by using chemical vapor deposition is 600 ± 100 Wm -1 K -1 compared with the thermal conductivity 419 Wm -1 K -1 of Ag. Carbon-nanotube-based liquids - a new class of nanomaterials, have shown many interesting properties and distinctive features offering potential in heat dissipation applications for electronic devices, such as computer microprocessor, high power LED, etc. In this work, a multiwalled carbon-nanotube-based liquid was made of well-dispersed hydroxyl-functional multiwalled carbon nanotubes (MWCNT-OH) in ethylene glycol (EG)/distilled water (DW) solutions by using Tween-80 surfactant and an ultrasonication method. The concentration of MWCNT-OH in EG/DW solutions ranged from 0.1 to 1.2 gram/liter. The dispersion of the MWCNT-OH-based EG/DW solutions was evaluated by using a Zeta-Sizer analyzer. The MWCNT-OH-based EG/DW solutions were used as coolants in the liquid cooling system for the Intel Core i5 processor. The thermal dissipation efficiency and the thermal response of the system were evaluated by directly measuring the temperature of the micro-processor using the Core Temp software and the temperature sensors built inside the micro-processor. The results confirmed the advantages of CNTs in thermal dissipation systems for computer processors and other high-power electronic devices.

Applications of carbon nanotubes-based biomaterials in biomedical nanotechnology.

Science.gov (United States)

Polizu, Stefania; Savadogo, Oumarou; Poulin, Philippe; Yahia, L'Hocine

2006-07-01

One of the facets of nanotechnology applications is the immense opportunities they offer for new developments in medicine and health sciences. Carbon nanotubes (CNTs) have particularly attracted attention for designing new monitoring systems for environment and living cells as well as nanosensors. Carbon nanotubes-based biomaterials are also employed as support for active prosthesis or functional matrices in reparation of parts of the human body. These nanostructures are studied as molecular-level building blocks for the complex and miniaturized medical device, and substrate for stimulation of cellular growth. The CNTs are cylindrical shaped with caged molecules which can act as nanoscale containers for molecular species, well required for biomolecular recognition and drug delivery systems. Endowed with very large aspect ratios, an excellent electrical conductivity and inertness along with mechanical robustness, nanotubes found enormous applications in molecular electronics and bioelectronics. The ballistic electrical behaviour of SWNTs conjugated with functionalization promotes a large variety of biosensors for individual molecules. Actuative response of CNTs is considered very promising feature for nanodevices, micro-robots and artificial muscles. An description of CNTs based biomaterials is attempted in this review, in order to point out their enormous potential for biomedical nanotechnology and nanobiotechnology.

Response of asymmetric carbon nanotube network devices to sub-terahertz and terahertz radiation

International Nuclear Information System (INIS)

Gayduchenko, I.; Kardakova, A.; Voronov, B.; Finkel, M.; Fedorov, G.; Jiménez, D.; Morozov, S.; Presniakov, M.; Goltsman, G.

2015-01-01

Demand for efficient terahertz radiation detectors resulted in intensive study of the asymmetric carbon nanostructures as a possible solution for that problem. It was maintained that photothermoelectric effect under certain conditions results in strong response of such devices to terahertz radiation even at room temperature. In this work, we investigate different mechanisms underlying the response of asymmetric carbon nanotube (CNT) based devices to sub-terahertz and terahertz radiation. Our structures are formed with CNT networks instead of individual CNTs so that effects probed are more generic and not caused by peculiarities of an individual nanoscale object. We conclude that the DC voltage response observed in our structures is not only thermal in origin. So called diode-type response caused by asymmetry of the device IV characteristic turns out to be dominant at room temperature. Quantitative analysis provides further routes for the optimization of the device configuration, which may result in appearance of novel terahertz radiation detectors

Considerably improved photovoltaic performance of carbon nanotube-based solar cells using metal oxide layers

Science.gov (United States)

Wang, Feijiu; Kozawa, Daichi; Miyauchi, Yuhei; Hiraoka, Kazushi; Mouri, Shinichiro; Ohno, Yutaka; Matsuda, Kazunari

2015-02-01

Carbon nanotube-based solar cells have been extensively studied from the perspective of potential application. Here we demonstrated a significant improvement of the carbon nanotube solar cells by the use of metal oxide layers for efficient carrier transport. The metal oxides also serve as an antireflection layer and an efficient carrier dopant, leading to a reduction in the loss of the incident solar light and an increase in the photocurrent, respectively. As a consequence, the photovoltaic performance of both p-single-walled carbon nanotube (SWNT)/n-Si and n-SWNT/p-Si heterojunction solar cells using MoOx and ZnO layers is improved, resulting in very high photovoltaic conversion efficiencies of 17.0 and 4.0%, respectively. These findings regarding the use of metal oxides as multifunctional layers suggest that metal oxide layers could improve the performance of various electronic devices based on carbon nanotubes.

Considerably improved photovoltaic performance of carbon nanotube-based solar cells using metal oxide layers.

Science.gov (United States)

Wang, Feijiu; Kozawa, Daichi; Miyauchi, Yuhei; Hiraoka, Kazushi; Mouri, Shinichiro; Ohno, Yutaka; Matsuda, Kazunari

2015-02-18

Carbon nanotube-based solar cells have been extensively studied from the perspective of potential application. Here we demonstrated a significant improvement of the carbon nanotube solar cells by the use of metal oxide layers for efficient carrier transport. The metal oxides also serve as an antireflection layer and an efficient carrier dopant, leading to a reduction in the loss of the incident solar light and an increase in the photocurrent, respectively. As a consequence, the photovoltaic performance of both p-single-walled carbon nanotube (SWNT)/n-Si and n-SWNT/p-Si heterojunction solar cells using MoOx and ZnO layers is improved, resulting in very high photovoltaic conversion efficiencies of 17.0 and 4.0%, respectively. These findings regarding the use of metal oxides as multifunctional layers suggest that metal oxide layers could improve the performance of various electronic devices based on carbon nanotubes.

High-efficiency perovskite solar cells based on anatase TiO{sub 2} nanotube arrays

Energy Technology Data Exchange (ETDEWEB)

Huang, Yan, E-mail: huangyan@ecust.edu.cn [School of Chemistry and Molecular Engineering, East China University of Science & Technology, Shanghai 200237 (China); Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Wu, Jiamin; Gao, Di [Department of Chemical and Petroleum Engineering, University of Pittsburgh, Pittsburgh, PA 15261 (United States)

2016-01-01

Perovskite solar cells (PSCs) based on one-dimensional anatase TiO{sub 2} nanotube arrays were prepared by using a two-step deposition method to fill the arrays of TiO{sub 2} nanotubes in different lengths with perovskite. The photovoltaic performance of PSCs was found to be significantly dependent on the length of the TiO{sub 2} nanotubes, and the power conversion efficiency decreased as the length of the TiO{sub 2} nanotubes increased from ~ 0.40 μm to ~ 0.65 and then to ~ 0.93 μm. The PSC fabricated with ~ 0.40 μm-long anatase TiO{sub 2} nanotube arrays yielded a power conversion efficiency of 11.3% and a fill factor of 0.68 under illumination of 100 mW/cm{sup 2} AM 1.5G simulated sunlight, which is significantly higher than previously reported solar cells based on 1-D TiO{sub 2} nanostructures. Incident photon-to-current efficiency and electrochemical impedance spectroscopy measurements indicated that longer TiO{sub 2} nanotubes led to higher recombination losses of charge carriers, possibly due to poor filling of the nanotube arrays with perovskite. - Highlights: • 1D anatase TiO{sub 2} nanotubes were used to fabricate perovskite solar cells. • The best efficiency of 11.3% was achieved with ~ 0.40 μm-long TiO{sub 2} nanotubes. • The efficiency of the devices decreased with increasing TiO{sub 2} nanotube lengths.

Analogue of electromagnetically-induced-transparency based on graphene nanotube waveguide

International Nuclear Information System (INIS)

Wei, Buzheng; Jian, Shuisheng

2017-01-01

A graphene-based nanotube waveguide system is proposed and designed to realize the analogue of electromagnetically-induced-transparency. The two nanotubes act as side coupled cavity rings which can be treated as the bright and dark resonators. By mimicking the quantum nonlinear optical interference, the light at resonant frequency makes the opaque system transparent. Conveniently, the working transparency window can be dynamically controlled by shifting the Fermi energy level of graphene without refabricating the device. Furthermore, the shape of the transmission spectrum can be tuned either by adjusting the waveguide coupling distance or by the cavity ring coupling distance. If the ring radius gets bigger, higher order of modes are excited in the dark resonator consequently. Meaningfully, the light travels at resonant frequency can be efficiently slowed down and the highest group delay reaches 25 ps. In the end, some concerns about the practical realization of such device are discussed. The structure may find potential applications in nano technology or light storage field. (paper)

Dielectrophoretic assembly of carbon nanotube devices

DEFF Research Database (Denmark)

Dimaki, Maria

The purpose of this project has been to assemble single-walled carbon nanotubes on electrodes at the tip of a biocompatible cantilever and use these for chemical species sensing in air and liquid, for example in order to measure the local activity from ion channels in the cell membrane....... The electrical resistance of carbon nanotubes has been shown to be extremely sensitive to gas molecules. Dielectrophoresis is a method capable of quickly attracting nanotubes on microelectrodes by using an electric field, thus enabling nanotube integration in microsystems. Dielectrophoresis offers also....... A model for the dielectrophoretic assembly of carbon nanotubes on microelectrodes was developed and several simulations were conducted using values from the available literature for the various key parameters. The model can give qualitative results regarding the parameters dominating the dielectrophoretic...

Use of Functionalized Carbon Nanotubes for Covalent Attachment of Nanotubes to Silicon

Science.gov (United States)

Tour, James M.; Dyke, Christopher A.; Maya, Francisco; Stewart, Michael P.; Chen, Bo; Flatt, Austen K.

2012-01-01

The purpose of the invention is to covalently attach functionalized carbon nanotubes to silicon. This step allows for the introduction of carbon nanotubes onto all manner of silicon surfaces, and thereby introduction of carbon nano - tubes covalently into silicon-based devices, onto silicon particles, and onto silicon surfaces. Single-walled carbon nanotubes (SWNTs) dispersed as individuals in surfactant were functionalized. The nano - tube was first treated with 4-t-butylbenzenediazonium tetrafluoroborate to give increased solubility to the carbon nanotube; the second group attached to the sidewall of the nanotube has a silyl-protected terminal alkyne that is de-protected in situ. This gives a soluble carbon nanotube that has functional groups appended to the sidewall that can be attached covalently to silicon. This reaction was monitored by UV/vis/NJR to assure direct covalent functionalization.

Growth of carbon nanotubes by Fe-catalyzed chemical vapor processes on silicon-based substrates

Science.gov (United States)

Angelucci, Renato; Rizzoli, Rita; Vinciguerra, Vincenzo; Fortuna Bevilacqua, Maria; Guerri, Sergio; Corticelli, Franco; Passini, Mara

2007-03-01

In this paper, a site-selective catalytic chemical vapor deposition synthesis of carbon nanotubes on silicon-based substrates has been developed in order to get horizontally oriented nanotubes for field effect transistors and other electronic devices. Properly micro-fabricated silicon oxide and polysilicon structures have been used as substrates. Iron nanoparticles have been obtained both from a thin Fe film evaporated by e-gun and from iron nitrate solutions accurately dispersed on the substrates. Single-walled nanotubes with diameters as small as 1 nm, bridging polysilicon and silicon dioxide “pillars”, have been grown. The morphology and structure of CNTs have been characterized by SEM, AFM and Raman spectroscopy.

High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes

International Nuclear Information System (INIS)

Kim, Byungwoo; Kim, Woong; Chung, Haegeun

2012-01-01

We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ∼75 F g −1 , ∼987 kW kg −1 and ∼27 W h kg −1 , respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (∼158 F g −1 ) and energy density (∼53 W h kg −1 ). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices. (paper)

High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes.

Science.gov (United States)

Kim, Byungwoo; Chung, Haegeun; Kim, Woong

2012-04-20

We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ~75 F g(-1), ~987 kW kg(-1) and ~27 W h kg(-1), respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (~158 F g(-1)) and energy density (~53 W h kg(-1)). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices. © 2012 IOP Publishing Ltd

High-performance supercapacitors based on vertically aligned carbon nanotubes and nonaqueous electrolytes

Science.gov (United States)

Kim, Byungwoo; Chung, Haegeun; Kim, Woong

2012-04-01

We demonstrate the high performance of supercapacitors fabricated with vertically aligned carbon nanotubes and nonaqueous electrolytes such as ionic liquids and conventional organic electrolytes. Specific capacitance, maximum power and energy density of the supercapacitor measured in ionic liquid were ˜75 F g-1, ˜987 kW kg-1 and ˜27 W h kg-1, respectively. The high power performance was consistently indicated by a fast relaxation time constant of 0.2 s. In addition, electrochemical oxidation of the carbon nanotubes improved the specific capacitance (˜158 F g-1) and energy density (˜53 W h kg-1). Both high power and energy density could be attributed to the fast ion transport realized by the alignment of carbon nanotubes and the wide operational voltage defined by the ionic liquid. The demonstrated carbon-nanotube- and nonaqueous-electrolyte-based supercapacitors show great potential for the development of high-performance energy storage devices.

Analytical modeling of glucose biosensors based on carbon nanotubes.

Science.gov (United States)

Pourasl, Ali H; Ahmadi, Mohammad Taghi; Rahmani, Meisam; Chin, Huei Chaeng; Lim, Cheng Siong; Ismail, Razali; Tan, Michael Loong Peng

2014-01-15

In recent years, carbon nanotubes have received widespread attention as promising carbon-based nanoelectronic devices. Due to their exceptional physical, chemical, and electrical properties, namely a high surface-to-volume ratio, their enhanced electron transfer properties, and their high thermal conductivity, carbon nanotubes can be used effectively as electrochemical sensors. The integration of carbon nanotubes with a functional group provides a good and solid support for the immobilization of enzymes. The determination of glucose levels using biosensors, particularly in the medical diagnostics and food industries, is gaining mass appeal. Glucose biosensors detect the glucose molecule by catalyzing glucose to gluconic acid and hydrogen peroxide in the presence of oxygen. This action provides high accuracy and a quick detection rate. In this paper, a single-wall carbon nanotube field-effect transistor biosensor for glucose detection is analytically modeled. In the proposed model, the glucose concentration is presented as a function of gate voltage. Subsequently, the proposed model is compared with existing experimental data. A good consensus between the model and the experimental data is reported. The simulated data demonstrate that the analytical model can be employed with an electrochemical glucose sensor to predict the behavior of the sensing mechanism in biosensors.

Carbon Nanotube based Nanotechnolgy

Science.gov (United States)

Meyyappan, M.

2000-10-01

Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.

Fluidics platform and method for sample preparation

Science.gov (United States)

Benner, Henry W.; Dzenitis, John M.

2016-06-21

Provided herein are fluidics platforms and related methods for performing integrated sample collection and solid-phase extraction of a target component of the sample all in one tube. The fluidics platform comprises a pump, particles for solid-phase extraction and a particle-holding means. The method comprises contacting the sample with one or more reagents in a pump, coupling a particle-holding means to the pump and expelling the waste out of the pump while the particle-holding means retains the particles inside the pump. The fluidics platform and methods herein described allow solid-phase extraction without pipetting and centrifugation.

Highly sensitive miniature fluidic flowmeter based on an FBG heated by Co2+-doped fiber

NARCIS (Netherlands)

Liu, Z.; Htein, L.; Cheng, L.K.; Martina, Q.; Jansen, R.; Tam, H.Y.

2017-01-01

In this paper, we present a miniature fluidic flow sensor based on a short fiber Bragg grating inscribed in a single mode fiber and heated by Co2+-doped multimode fibers. The proposed flow sensor was employed to measure the flow rates of oil and water, showing good sensitivity of 0.339 nm/(m/s) and

Dissolvable fluidic time delays for programming multi-step assays in instrument-free paper diagnostics.

Science.gov (United States)

Lutz, Barry; Liang, Tinny; Fu, Elain; Ramachandran, Sujatha; Kauffman, Peter; Yager, Paul

2013-07-21

Lateral flow tests (LFTs) are an ingenious format for rapid and easy-to-use diagnostics, but they are fundamentally limited to assay chemistries that can be reduced to a single chemical step. In contrast, most laboratory diagnostic assays rely on multiple timed steps carried out by a human or a machine. Here, we use dissolvable sugar applied to paper to create programmable flow delays and present a paper network topology that uses these time delays to program automated multi-step fluidic protocols. Solutions of sucrose at different concentrations (10-70% of saturation) were added to paper strips and dried to create fluidic time delays spanning minutes to nearly an hour. A simple folding card format employing sugar delays was shown to automate a four-step fluidic process initiated by a single user activation step (folding the card); this device was used to perform a signal-amplified sandwich immunoassay for a diagnostic biomarker for malaria. The cards are capable of automating multi-step assay protocols normally used in laboratories, but in a rapid, low-cost, and easy-to-use format.

Noise And Charge Transport In Carbon Nanotube Devices

Science.gov (United States)

Reza, Shahed; Huynh, Quyen T.; Bosman, Gijs; Sippel, Jennifer; Rinzler, Andrew G.

2005-11-01

The charge transport and noise properties of three terminal, gated devices containing multiple, single wall, metallic and semiconductor carbon nanotubes have been measured as a function of gate and drain bias at 300K. Using pulsed bias the metallic tubes could be burned sequentially enabling the separation of measured conductance and low frequency excess noise into metallic and semiconductor contributions. The relative low frequency excess noise of the metallic tubes was about a factor 100 lower than that of the semiconductor tubes, whereas the conductance of the metallic tubes was significantly higher (10 to 50 times) than that of the semiconductor tubes.

Carbon Nanotube-Based Synthetic Gecko Tapes

Science.gov (United States)

Dhinojwala, Ali

2008-03-01

Wall-climbing geckos have unique ability to attach to different surfaces without the use of any viscoelastic glues. On coming in contact with any surface, the micron-size gecko foot-hairs deform, enabling molecular contact over large areas, thus translating weak van der Waals (vdW) interactions into enormous shear forces. We will present our recent results on the development of synthetic gecko tape using aligned carbon nanotubes to mimic the keratin hairs found on gecko feet. The patterned carbon nanotube-based gecko tape can support a shear stress (36 N/cm^2) nearly four times higher than the gecko foot and sticks to a variety of surfaces, including Teflon. Both the micron-size setae (replicated by nanotube bundles) and nanometer-size spatulas (individual nanotubes) are necessary to achieve macroscopic shear adhesion and to translate the weak vdW interactions into high shear forces. The carbon nanotube based tape offers an excellent synthetic option as a dry conductive reversible adhesive in microelectronics, robotics and space applications. The mechanism behind these large shear forces and self-cleaning properties of these carbon nanotube based synthetic gecko tapes will be discussed. This work was performed in collaboration with graduate students Liehui Ge, and Sunny Sethi, and collaborators from RPI; Lijie Ci and Professor Pulickel Ajayan.

Evaluation of the threshold trimming method for micro inertial fluidic switch based on electrowetting technology

Directory of Open Access Journals (Sweden)

Tingting Liu

2014-03-01

Full Text Available The switch based on electrowetting technology has the advantages of no moving part, low contact resistance, long life and adjustable acceleration threshold. The acceleration threshold of switch can be fine-tuned by adjusting the applied voltage. This paper is focused on the electrowetting properties of switch and the influence of microchannel structural parameters, applied voltage and droplet volume on acceleration threshold. In the presence of process errors of micro inertial fluidic switch and measuring errors of droplet volume, there is a deviation between test acceleration threshold and target acceleration threshold. Considering the process errors and measuring errors, worst-case analysis is used to analyze the influence of parameter tolerance on the acceleration threshold. Under worst-case condition the total acceleration threshold tolerance caused by various errors is 9.95%. The target acceleration threshold can be achieved by fine-tuning the applied voltage. The acceleration threshold trimming method of micro inertial fluidic switch is verified.

AC-driven organic light emission devices with carbon nanotubes

Science.gov (United States)

Jeon, So-Yeon; Yu, SeGi

2017-02-01

We have investigated alternating current (AC)-driven organic light-emitting devices (OLEDs), with carbon nanotubes (CNTs) incorporated within the emission layer. With CNT incorporation, the brightness of the OLEDs was substantially improved, and the turn-on voltage was reduced by at least a factor of five. Furthermore, the current levels of the CNT-incorporated OLEDs were lower than that of the reference device. A roughly 70% decrease in the current level was obtained for a CNT concentration of 0.03 wt%. This was accomplished by keeping the concentration of CNTs low and the length of CNTs short, which helped to suppress the percolation networking of CNTs within the emitting layer. Strong local electric fields near the end-tips of CNTs and micro-capacitors formed by dispersed CNTs might have caused this high brightness and these low currents. CNT incorporation in the emitting layer can improve the characteristics of AC-driven OLEDs, which are considered to be one of the candidates for flat panel displays and lightning devices.

AC-driven Organic Light Emission Devices with Carbon Nanotubes

Energy Technology Data Exchange (ETDEWEB)

Jeon, So-Yeon [Sungkyunkwan University, Suwon (Korea, Republic of); Yu, SeGi [Hankuk University of Foreign Studies, Yongin (Korea, Republic of)

2017-02-15

We have investigated alternating current (AC)-driven organic light-emitting devices (OLEDs), with carbon nanotubes (CNTs) incorporated within the emission layer. With CNT incorporation, the brightness of the OLEDs was substantially improved, and the turn-on voltage was reduced by at least a factor of five. Furthermore, the current levels of the CNT-incorporated OLEDs were lower than that of the reference device. A roughly 70% decrease in the current level was obtained for a CNT concentration of 0.03 wt%. This was accomplished by keeping the concentration of CNTs low and the length of CNTs short, which helped to suppress the percolation networking of CNTs within the emitting layer. Strong local electric fields near the end-tips of CNTs and micro-capacitors formed by dispersed CNTs might have caused this high brightness and these low currents. CNT incorporation in the emitting layer can improve the characteristics of AC-driven OLEDs, which are considered to be one of the candidates for flat panel displays and lightning devices.

Miniaturized pH Sensors Based on Zinc Oxide Nanotubes/Nanorods

Directory of Open Access Journals (Sweden)

Magnus Willander

2009-11-01

Full Text Available ZnO nanotubes and nanorods grown on gold thin film were used to create pH sensor devices. The developed ZnO nanotube and nanorod pH sensors display good reproducibility, repeatability and long-term stability and exhibit a pH-dependent electrochemical potential difference versus an Ag/AgCl reference electrode over a large dynamic pH range. We found the ZnO nanotubes provide sensitivity as high as twice that of the ZnO nanorods, which can be ascribed to the fact that small dimensional ZnO nanotubes have a higher level of surface and subsurface oxygen vacancies and provide a larger effective surface area with higher surface-to-volume ratio as compared to ZnO nanorods, thus affording the ZnO nanotube pH sensor a higher sensitivity. Experimental results indicate ZnO nanotubes can be used in pH sensor applications with improved performance. Moreover, the ZnO nanotube arrays may find potential application as a novel material for measurements of intracellular biochemical species within single living cells.

Multi-walled carbon nano-tubes for energy storage and production applications

International Nuclear Information System (INIS)

Andrews, R.; Jacques, D.; Likpa, S.; Qian, D.; Rantell, T.; Anthony, J.

2005-01-01

Full text of publication follows: Since their discovery, carbon nano-tubes have been proposed as candidate materials for a broad range of applications, including high strength composites, molecular electronics, and energy storage. In many cases, nano-tubes have been proposed to replace traditional carbon materials, such as activated carbons in energy storage devices. In other cases, novel applications have been proposed, such as the use of carbon nano-tube arrays in photovoltaic devices. The use of multi-walled carbon nano-tubes in energy storage devices has generated great interest due to their high inherent conductivity, layered structure, and high surface area per volume compared to traditional graphitic materials. However as produced nano-tubes do not possess ideal properties, and exhibit only modest charge storage. We have explored the charge storage abilities of nano-tubes with varying morphologies (fullerenic versus stacked cones), nano-tubes containing N or B dopants, as well as various post-treatments of the nano-tubes. The use of nano-tubes in charge storage devices will be described, as well as modification of the nano-tube surfaces or morphology to improve this performance. The synthesis of nano-tubes with several differing hetero-atom dopants will also be described, as well as the effect of heat treatment on these structures. One of the most significant problems in organic photovoltaics is the typically low charge-carrier mobility in organic thin films which, coupled with short exciton diffusion lengths, means that photo-generated charge-carrier pairs are more likely to re-combine than reach an electrode to generate current. Two organic systems with high charge-carrier mobilities are carbon nano-tubes (here, MWNTs) and acene-based organic semiconductors. We believe that blended devices based on MWNTs and organic semiconductors could lead to the next class of efficient, flexible and inexpensive organic photovoltaic systems. We have developed methods to

Electric moulding of dispersed lipid nanotubes into a nanofluidic device.

Science.gov (United States)

Frusawa, Hiroshi; Manabe, Tatsuhiko; Kagiyama, Eri; Hirano, Ken; Kameta, Naohiro; Masuda, Mitsutoshi; Shimizu, Toshimi

2013-01-01

Hydrophilic nanotubes formed by lipid molecules have potential applications as platforms for chemical or biological events occurring in an attolitre volume inside a hollow cylinder. Here, we have integrated the lipid nanotubes (LNTs) by applying an AC electric field via plug-in electrode needles placed above a substrate. The off-chip assembly method has the on-demand adjustability of an electrode configuration, enabling the dispersed LNT to be electrically moulded into a separate film of parallel LNT arrays in one-step. The fluorescence resonance energy transfer technique as well as the digital microscopy visualised the overall filling of gold nanoparticles up to the inner capacity of an LNT film by capillary action, thereby showing the potential of this flexible film for use as a high-throughput nanofluidic device where not only is the endo-signalling and product in each LNT multiplied but also the encapsulated objects are efficiently transported and reacted.

Heat Dissipation for Microprocessor Using Multiwalled Carbon Nanotubes Based Liquid

Science.gov (United States)

Trinh, Pham Van; Chuc, Nguyen Van; Khoi, Phan Hong; Minh, Phan Ngoc

2013-01-01

Carbon nanotubes (CNTs) are one of the most valuable materials with high thermal conductivity (2000 W/m · K compared with thermal conductivity of Ag 419 W/m · K). This suggested an approach in applying the CNTs in thermal dissipation system for high power electronic devices, such as computer processor and high brightness light emitting diode (HB-LED). In this work, multiwalled carbon nanotubes (MWCNTs) based liquid was made by COOH functionalized MWCNTs dispersed in distilled water with concentration in the range between 0.2 and 1.2 gram/liter. MWCNT based liquid was used in liquid cooling system to enhance thermal dissipation for computer processor. By using distilled water in liquid cooling system, CPU's temperature decreases by about 10°C compared with using fan cooling system. By using MWCNT liquid with concentration of 1 gram/liter MWCNTs, the CPU's temperature decreases by 7°C compared with using distilled water in cooling system. Theoretically, we also showed that the presence of MWCNTs reduced thermal resistance and increased the thermal conductivity of liquid cooling system. The results have confirmed the advantages of the MWCNTs for thermal dissipation systems for the μ-processor and other high power electronic devices. PMID:24453829

Precision Controlled Carbon Materials for Next-Generation Optoelectronic and Photonic Devices

Science.gov (United States)

2018-01-08

engineer next-generation carbon-based optoelectronic and photonic devices with superior performance and capabilities. These devices include carbon...electronics; (4) nanostructured graphene plasmonics; and (5) polymer-nanotube conjugate chemistry . (1) Semiconducting carbon nanotube-based...applications (In Preparation, 2018). (5) Polymer-nanotube conjugate chemistry Conjugated polymers can be exploited as agents for selectively wrapping and

Reduced graphene oxide and vertically aligned carbon nanotubes superhydrophilic films for supercapacitors devices

Energy Technology Data Exchange (ETDEWEB)

Zanin, H., E-mail: hudsonzanin@gmail.com [Associated Laboratory of Sensors and Materials of the National Institute for Space Research, Av. dos Astronautas 1758, Sao Jose dos Campos CEP 12227-010, SP (Brazil); Departamento de Semicondutores, Instrumentos e Fotônica, Faculdade de Engenharia Elétrica e Computação, Universidade Estadual de Campinas, UNICAMP, Campinas 13083-970 (Brazil); Saito, E., E-mail: esaito135@gmail.com [Associated Laboratory of Sensors and Materials of the National Institute for Space Research, Av. dos Astronautas 1758, Sao Jose dos Campos CEP 12227-010, SP (Brazil); Ceragioli, H.J., E-mail: helderjc@gmail.com [Departamento de Semicondutores, Instrumentos e Fotônica, Faculdade de Engenharia Elétrica e Computação, Universidade Estadual de Campinas, UNICAMP, Campinas 13083-970 (Brazil); Baranauskas, V., E-mail: vitor@dsif.fee.unicamp.br [Departamento de Semicondutores, Instrumentos e Fotônica, Faculdade de Engenharia Elétrica e Computação, Universidade Estadual de Campinas, UNICAMP, Campinas 13083-970 (Brazil); Corat, E.J., E-mail: corat@las.inpe.br [Associated Laboratory of Sensors and Materials of the National Institute for Space Research, Av. dos Astronautas 1758, Sao Jose dos Campos CEP 12227-010, SP (Brazil)

2014-01-01

Graphical abstract: - Highlights: • Graphene nanosheets were produced onto wire rods. • RGO and VACNT-O were evaluated and compared as supercapacitor electrode. • RGO and VACNT-O have structural and electrochemical properties quite similars. • The materials present good specific capacitance, energy storage and power delivery. - Abstract: Reduced graphene oxide (RGO) and vertically aligned carbon nanotubes (VACNT) superhydrophilic films were prepared by chemical vapor deposition techniques for electrical energy storage investigations. These electrodes were characterized in terms of their material and electrochemical properties by scanning electron microscopy (SEM), surface wettability, Fourier transform infrared spectroscopy (FTIR), energy dispersive and Raman spectroscopies, cyclic voltammetry (CV) and galvanostatic charge–discharge. We observed several physical structural and electrochemical similarities between these carbon-based materials with particular attention to very good specific capacitance, ultra-high energy storage and fast power delivery. Our results showed that the main difference between specific capacitance values is attributed to pseudocapacitive contribution and high density of multiwall nanotubes tips. In this work we have tested a supercapacitor device using the VACNT electrodes.

The detection of improvised nonmilitary peroxide based explosives using a titania nanotube array sensor

International Nuclear Information System (INIS)

Banerjee, Subarna; Mohapatra, Susanta K; Misra, Mano; Mishra, Indu B

2009-01-01

There is a critical need to develop an efficient, reliable and highly selective sensor for the detection of improvised nonmilitary explosives. This paper describes the utilization of functionalized titania nanotube arrays for sensing improvised organic peroxide explosives such as triacetone triperoxide (TATP). TATP forms complexes with titania nanotube arrays (prepared by anodization and sensitized with zinc ions) and thus affects the electron state of the nanosensing device, which is signaled as a change in current of the overall nanotube material. The response is rapid and a signal of five to eight orders of magnitude is observed. These nanotube array sensors can be used as hand-held miniaturized devices as well as large scale portable units for military and homeland security applications.

The detection of improvised nonmilitary peroxide based explosives using a titania nanotube array sensor.

Science.gov (United States)

Banerjee, Subarna; Mohapatra, Susanta K; Misra, Mano; Mishra, Indu B

2009-02-18

There is a critical need to develop an efficient, reliable and highly selective sensor for the detection of improvised nonmilitary explosives. This paper describes the utilization of functionalized titania nanotube arrays for sensing improvised organic peroxide explosives such as triacetone triperoxide (TATP). TATP forms complexes with titania nanotube arrays (prepared by anodization and sensitized with zinc ions) and thus affects the electron state of the nanosensing device, which is signaled as a change in current of the overall nanotube material. The response is rapid and a signal of five to eight orders of magnitude is observed. These nanotube array sensors can be used as hand-held miniaturized devices as well as large scale portable units for military and homeland security applications.

Three-dimensional wax patterning of paper fluidic devices.

Science.gov (United States)

Renault, Christophe; Koehne, Jessica; Ricco, Antonio J; Crooks, Richard M

2014-06-17

In this paper we describe a method for three-dimensional wax patterning of microfluidic paper-based analytical devices (μPADs). The method is rooted in the fundamental details of wax transport in paper and provides a simple way to fabricate complex channel architectures such as hemichannels and fully enclosed channels. We show that three-dimensional μPADs can be fabricated with half as much paper by using hemichannels rather than ordinary open channels. We also provide evidence that fully enclosed channels are efficiently isolated from the exterior environment, decreasing contamination risks, simplifying the handling of the device, and slowing evaporation of solvents.

Microfiber devices based on carbon materials

OpenAIRE

Gengzhi Sun; Xuewan Wang; Peng Chen

2015-01-01

Microfiber devices are able to extend the micro/nano functionalities of materials or devices to the macroscopic scale with excellent flexibility and weavability, promising a variety of unique applications and, sometimes, also improved performance as compared with bulk counterparts. The fiber electrodes in these devices are often made of carbon materials (e.g. carbon nanotubes and graphene) because of their exceptional electrical, mechanical, and structural properties. Covering the latest deve...

Facile Preparation of Carbon-Nanotube-based 3-Dimensional Transparent Conducting Networks for Flexible Noncontact Sensing Device

KAUST Repository

Tai, Yanlong; Lubineau, Gilles

2016-01-01

Here, we report the controllable fabrication of transparent conductive films (TCFs) for moisture-sensing applications based on heating-rate-triggered, 3-dimensional porous conducting networks of single-walled carbon nanotube (SWCNT)/poly(3

Carbon nanotubes for coherent spintronics

DEFF Research Database (Denmark)

Kuemmeth, Ferdinand; Churchill, H O H; Herring, P K

2010-01-01

Carbon nanotubes bridge the molecular and crystalline quantum worlds, and their extraordinary electronic, mechanical and optical properties have attracted enormous attention from a broad scientific community. We review the basic principles of fabricating spin-electronic devices based on individual......, electrically-gated carbon nanotubes, and present experimental efforts to understand their electronic and nuclear spin degrees of freedom, which in the future may enable quantum applications....

Electrostatic sensing and electrochemistry with single carbon nanotubes

NARCIS (Netherlands)

Heller, I.

2009-01-01

This thesis describes the experimental study of devices based on single carbon nanotubes in the context of (bio)sensing in aqueous solutions. Carbon nanotubes are cylindrical molecules of sp2- carbon, about one nanometer in diameter and typically several micrometers long, which have semiconducting

Integrated electronics and fluidic MEMS for bioengineering

Science.gov (United States)

Fok, Ho Him Raymond

Microelectromechanical systems (MEMS) and microelectronics have become enabling technologies for many research areas. This dissertation presents the use of fluidic MEMS and microelectronics for bioengineering applications. In particular, the versatility of MEMS and microelectronics is highlighted by the presentation of two different applications, one for in-vitro study of nano-scale dynamics during cell division and one for in-vivo monitoring of biological activities at the cellular level. The first application of an integrated system discussed in this dissertation is to utilize fluidic MEMS for studying dynamics in the mitotic spindle, which could lead to better chemotherapeutic treatments for cancer patients. Previous work has developed the use of electrokinetic phenomena on the surface of a glass-based platform to assemble microtubules, the building blocks of mitotic spindles. Nevertheless, there are two important limitations of this type of platform. First, an unconventional microfabrication process is necessary for the glass-based platform, which limits the utility of this platform. In order to overcome this limitation, in this dissertation a convenient microfluidic system is fabricated using a negative photoresist called SU-8. The fabrication process for the SU-8-based system is compatible with other fabrication techniques used in developing microelectronics, and this compatibility is essential for integrating electronics for studying dynamics in the mitotic spindle. The second limitation of the previously-developed glass-based platform is its lack of bio-compatibility. For example, microtubules strongly interact with the surface of the glass-based platform, thereby hindering the study of dynamics in the mitotic spindle. This dissertation presents a novel approach for assembling microtubules away from the surface of the platform, and a fabrication process is developed to assemble microtubules between two self-aligned thin film electrodes on thick SU-8

FLUIDIC AC AMPLIFIERS.

Science.gov (United States)

Several fluidic tuned AC Amplifiers were designed and tested. Interstage tuning and feedback designs are considered. Good results were obtained...corresponding Q’s as high as 12. Element designs and test results of one, two, and three stage amplifiers are presented. AC Modulated Carrier Systems

Fluidic pumping system

International Nuclear Information System (INIS)

Wilson, P.D.

1995-01-01

A fluidic pumping system comprises two charge vessels which communicate with a liquid inlet and a liquid outlet through a fluidic bridge rectifier. A pressurising and depressurising arrangement for alternately pressurising and depressurising the charge vessels comprises a chamber containing a piston and being in communication with the charge vessels. Drive means not mechanically connected to the piston are provided for causing reciprocatory movement of the piston. Movement of the piston in one direction causes pressurisation of one charge vessel to discharge a liquid therefrom through the liquid outlet. Simultaneously, the other charge vessel is depressurised to draw liquid from the liquid inlet into the depressurised charge vessel. Preferably, the drive means for the piston comprises an external solenoid winding at each end of a horizontally arranged chamber. Alternatively, the chamber may be vertically disposed with an external solenoid winding at the upper end of the chamber to effect upward movement of the piston, the piston then falling under gravity upon de-energisation of the winding. (UK)

Stationary scanning x-ray source based on carbon nanotube field emitters

International Nuclear Information System (INIS)

Zhang, J.; Yang, G.; Cheng, Y.; Gao, B.; Qiu, Q.; Lee, Y.Z.; Lu, J.P.; Zhou, O.

2005-01-01

We report a field emission x-ray source that can generate a scanning x-ray beam to image an object from multiple projection angles without mechanical motion. The key component of the device is a gated carbon nanotube field emission cathode with an array of electron emitting pixels that are individually addressable via a metal-oxide-semiconductor field effect transistor-based electronic circuit. The characteristics of this x-ray source are measured and its imaging capability is demonstrated. The device can potentially lead to a fast data acquisition rate for laminography and tomosynthesis with a simplified experimental setup

Properties of single-walled carbon nanotube-based aerogels as a function of nanotube loading

International Nuclear Information System (INIS)

Worsley, Marcus A.; Pauzauskie, Peter J.; Kucheyev, Sergei O.; Zaug, Joseph M.; Hamza, Alex V.; Satcher, Joe H.; Baumann, Theodore F.

2009-01-01

Here, we present the synthesis and characterization of low-density single-walled carbon nanotube-based aerogels (SWNT-CA). Aerogels with varying nanotube loading (0-55 wt.%) and density (20-350 mg cm -3 ) were fabricated and characterized by four-probe method, electron microscopy, Raman spectroscopy and nitrogen porosimetry. Several properties of the SWNT-CAs were highly dependent upon nanotube loading. At nanotube loadings of 55 wt.%, shrinkage of the aerogel monoliths during carbonization and drying was almost completely eliminated. Electrical conductivities are improved by an order of magnitude for the SWNT-CA (55 wt.% nanotubes) compared to those of foams without nanotubes. Surface areas as high as 184 m 2 g -1 were achieved for SWNT-CAs with greater than 20 wt.% nanotube loading.

Fringing-field dielectrophoretic assembly of ultrahigh-density semiconducting nanotube arrays with a self-limited pitch

Science.gov (United States)

Cao, Qing; Han, Shu-Jen; Tulevski, George S.

2014-09-01

One key challenge of realizing practical high-performance electronic devices based on single-walled carbon nanotubes is to produce electronically pure nanotube arrays with both a minuscule and uniform inter-tube pitch for sufficient device-packing density and homogeneity. Here we develop a method in which the alternating voltage-fringing electric field formed between surface microelectrodes and the substrate is utilized to assemble semiconducting nanotubes into well-aligned, ultrahigh-density and submonolayered arrays, with a consistent pitch as small as 21±6 nm determined by a self-limiting mechanism, based on the unique field focusing and screening effects of the fringing field. Field-effect transistors based on such nanotube arrays exhibit record high device transconductance (>50 μS μm-1) and decent on current per nanotube (~1 μA per tube) together with high on/off ratios at a drain bias of -1 V.

Fabrication and electrical properties of single wall carbon nanotube channel and graphene electrode based transistors arrays

Energy Technology Data Exchange (ETDEWEB)

Seo, M.; Kim, H.; Kim, Y. H.; Yun, H.; McAllister, K.; Lee, S. W., E-mail: leesw@konkuk.ac.kr [Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Na, J.; Kim, G. T. [School of Electrical Engineering, Korea University, Seoul 136-701 (Korea, Republic of); Lee, B. J.; Kim, J. J.; Jeong, G. H. [Department of Nano Applied Engineering, Kangwon National University, Kangwon-do 200-701 (Korea, Republic of); Lee, I.; Kim, K. S. [Department of Physics and Graphene Research Institute, Sejong University, Seoul 143-747 (Korea, Republic of)

2015-07-20

A transistor structure composed of an individual single-walled carbon nanotube (SWNT) channel with a graphene electrode was demonstrated. The integrated arrays of transistor devices were prepared by transferring patterned graphene electrode patterns on top of the aligned SWNT along one direction. Both single and multi layer graphene were used for the electrode materials; typical p-type transistor and Schottky diode behavior were observed, respectively. Based on our fabrication method and device performances, several issues are suggested and discussed to improve the device reliability and finally to realize all carbon based future electronic systems.

Laser-assisted simultaneous transfer and patterning of vertically aligned carbon nanotube arrays on polymer substrates for flexible devices.

Science.gov (United States)

In, Jung Bin; Lee, Daeho; Fornasiero, Francesco; Noy, Aleksandr; Grigoropoulos, Costas P

2012-09-25

We demonstrate a laser-assisted dry transfer technique for assembling patterns of vertically aligned carbon nanotube arrays on a flexible polymeric substrate. A laser beam is applied to the interface of a nanotube array and a polycarbonate sheet in contact with one another. The absorbed laser heat promotes nanotube adhesion to the polymer in the irradiated regions and enables selective pattern transfer. A combination of the thermal transfer mechanism with rapid direct writing capability of focused laser beam irradiation allows us to achieve simultaneous material transfer and direct micropatterning in a single processing step. Furthermore, we demonstrate that malleability of the nanotube arrays transferred onto a flexible substrate enables post-transfer tailoring of electric conductance by collapsing the aligned nanotubes in different directions. This work suggests that the laser-assisted transfer technique provides an efficient route to using vertically aligned nanotubes as conductive elements in flexible device applications.

No-moving-part electro/fluidic transducer based on plasma discharge effect

Czech Academy of Sciences Publication Activity Database

Tesař, Václav; Šonský, Jiří

2015-01-01

Roč. 232, August (2015), s. 20-29 ISSN 0924-4247 R&D Projects: GA ČR GA13-23046S Institutional support: RVO:61388998 Keywords : transducer * fluidic * plasma discharge Subject RIV: BK - Fluid Dynamics Impact factor: 2.201, year: 2015 http://www.sciencedirect.com/science/article/pii/S092442471500206X

Microfluidic hubs, systems, and methods for interface fluidic modules

Science.gov (United States)

Bartsch, Michael S; Claudnic, Mark R; Kim, Hanyoup; Patel, Kamlesh D; Renzi, Ronald F; Van De Vreugde, James L

2015-01-27

Embodiments of microfluidic hubs and systems are described that may be used to connect fluidic modules. A space between surfaces may be set by fixtures described herein. In some examples a fixture may set substrate-to-substrate spacing based on a distance between registration surfaces on which the respective substrates rest. Fluidic interfaces are described, including examples where fluid conduits (e.g. capillaries) extend into the fixture to the space between surfaces. Droplets of fluid may be introduced to and/or removed from microfluidic hubs described herein, and fluid actuators may be used to move droplets within the space between surfaces. Continuous flow modules may be integrated with the hubs in some examples.

Lambertian white top-emitting organic light emitting device with carbon nanotube cathode

Science.gov (United States)

Freitag, P.; Zakhidov, Al. A.; Luessem, B.; Zakhidov, A. A.; Leo, K.

2012-12-01

We demonstrate that white organic light emitting devices (OLEDs) with top carbon nanotube (CNT) electrodes show almost no microcavity effect and exhibit essentially Lambertian emission. CNT top electrodes were applied by direct lamination of multiwall CNT sheets onto white small molecule OLED stack. The devices show an external quantum efficiency of 1.5% and high color rendering index of 70. Due to elimination of the cavity effect, the devices show good color stability for different viewing angles. Thus, CNT electrodes are a viable alternative to thin semitransparent metallic films, where the strong cavity effect causes spectral shift and non-Lambertian angular dependence. Our method of the device fabrication is simple yet effective and compatible with virtually any small molecule organic semiconductor stack. It is also compatible with flexible substrates and roll-to-roll fabrication.

Carbon based nanostructures: diamond clusters structured with nanotubes

Directory of Open Access Journals (Sweden)

O.A. Shenderova

2003-01-01

Full Text Available Feasibility of designing composites from carbon nanotubes and nanodiamond clusters is discussed based on atomistic simulations. Depending on nanotube size and morphology, some types of open nanotubes can be chemically connected with different facets of diamond clusters. The geometrical relation between different types of nanotubes and different diamond facets for construction of mechanically stable composites with all bonds saturated is summarized. Potential applications of the suggested nanostructures are briefly discussed based on the calculations of their electronic properties using environment dependent self-consistent tight-binding approach.

Laser-Assisted Simultaneous Transfer and Patterning of Vertically Aligned Carbon Nanotube Arrays on Polymer Substrates for Flexible Devices

KAUST Repository

In, Jung Bin

2012-09-25

We demonstrate a laser-assisted dry transfer technique for assembling patterns of vertically aligned carbon nanotube arrays on a flexible polymeric substrate. A laser beam is applied to the interface of a nanotube array and a polycarbonate sheet in contact with one another. The absorbed laser heat promotes nanotube adhesion to the polymer in the irradiated regions and enables selective pattern transfer. A combination of the thermal transfer mechanism with rapid direct writing capability of focused laser beam irradiation allows us to achieve simultaneous material transfer and direct micropatterning in a single processing step. Furthermore, we demonstrate that malleability of the nanotube arrays transferred onto a flexible substrate enables post-transfer tailoring of electric conductance by collapsing the aligned nanotubes in different directions. This work suggests that the laser-assisted transfer technique provides an efficient route to using vertically aligned nanotubes as conductive elements in flexible device applications. © 2012 American Chemical Society.

Research of Dielectric Breakdown Micro fluidic Sampling Chip

International Nuclear Information System (INIS)

Jiang, F.; Lei, Y.; Yu, J.

2013-01-01

Micro fluidic chip is mainly driven electrically by external electrode and array electrode, but there are certain disadvantages in both of ways, which affect the promotion and application of micro fluidic technology. This paper discusses a scheme that uses the conductive solution in a microchannel made by PDMS, replacing electrodes and the way of dielectric breakdown to achieve microfluidic chip driver. It could reduce the driving voltage and simplify the chip production process. To prove the feasibility of this method, we produced a micro fluidic chip used in PDMS material with the lithography technology and experimented it. The results showed that using the dielectric breakdown to achieve microfluidic chip driver is feasible, and it has certain application prospect.

Heating-Rate-Triggered Carbon-Nanotube-based 3-Dimensional Conducting Networks for a Highly Sensitive Noncontact Sensing Device

KAUST Repository

Tai, Yanlong

2016-01-28

Recently, flexible and transparent conductive films (TCFs) are drawing more attention for their central role in future applications of flexible electronics. Here, we report the controllable fabrication of TCFs for moisture-sensing applications based on heating-rate-triggered, 3-dimensional porous conducting networks through drop casting lithography of single-walled carbon nanotube (SWCNT)/poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) ink. How ink formula and baking conditions influence the self-assembled microstructure of the TCFs is discussed. The sensor presents high-performance properties, including a reasonable sheet resistance (2.1 kohm/sq), a high visible-range transmittance (>69%, PET = 90%), and good stability when subjected to cyclic loading (>1000 cycles, better than indium tin oxide film) during processing, when formulation parameters are well optimized (weight ratio of SWCNT to PEDOT:PSS: 1:0.5, SWCNT concentration: 0.3 mg/ml, and heating rate: 36 °C/minute). Moreover, the benefits of these kinds of TCFs were verified through a fully transparent, highly sensitive, rapid response, noncontact moisture-sensing device (5 × 5 sensing pixels).

Enhanced UV photoresponse of KrF-laser-synthesized single-wall carbon nanotubes/n-silicon hybrid photovoltaic devices.

Science.gov (United States)

Le Borgne, V; Gautier, L A; Castrucci, P; Del Gobbo, S; De Crescenzi, M; El Khakani, M A

2012-06-01

We report on the KrF-laser ablation synthesis, purification and photocurrent generation properties of single-wall carbon nanotubes (SWCNTs). The thermally purified SWCNTs are integrated into hybrid photovoltaic (PV) devices by spin-coating them onto n-Si substrates. These novel SWCNTs/n-Si hybrid devices are shown to generate significant photocurrent (PC) over the entire 250-1050 nm light spectrum with external quantum efficiencies (EQE) reaching up to ~23%. Our SWCNTs/n-Si hybrid devices are not only photoactive in the traditional spectral range of Si solar cells, but generate also significant PC in the UV domain (below 400 nm). This wider spectral response is believed to be the result of PC generation from both the SWCNTs themselves and the tremendous number of local p-n junctions created at the nanotubes/Si interface. To assess the prevalence of these two contributions, the EQE spectra and J-V characteristics of these hybrid devices were investigated in both planar and top-down configurations, as a function of SWCNTs' film thickness. A sizable increase in EQE in the near UV with respect to the silicon is observed in both configurations, with a more pronounced UV photoresponse in the planar mode, confirming thereby the role of SWCNTs in the photogeneration process. The PC generation is found to reach its maximum for an optimal the SWCNT film thickness, which is shown to correspond to the best trade-off between lowest electrical resistance and highest optical transparency. Finally, by analyzing the J-V characteristics of our SWCNTs/n-Si devices with an equivalent circuit model, we were able to point out the contribution of the various electrical components involved in the photogeneration process. The SWCNTs-based devices demonstrated here open up the prospect for their use in highly effective photovoltaics and/or UV-light sensors.

Air-gating and chemical-gating in transistors and sensing devices made from hollow TiO2 semiconductor nanotubes

Science.gov (United States)

Alivov, Yahya; Funke, Hans; Nagpal, Prashant

2015-07-01

Rapid miniaturization of electronic devices down to the nanoscale, according to Moore’s law, has led to some undesirable effects like high leakage current in transistors, which can offset additional benefits from scaling down. Development of three-dimensional transistors, by spatial extension in the third dimension, has allowed higher contact area with a gate electrode and better control over conductivity in the semiconductor channel. However, these devices do not utilize the large surface area and interfaces for new electronic functionality. Here, we demonstrate air gating and chemical gating in hollow semiconductor nanotube devices and highlight the potential for development of novel transistors that can be modulated using channel bias, gate voltage, chemical composition, and concentration. Using chemical gating, we reversibly altered the conductivity of nanoscaled semiconductor nanotubes (10-500 nm TiO2 nanotubes) by six orders of magnitude, with a tunable rectification factor (ON/OFF ratio) ranging from 1-106. While demonstrated air- and chemical-gating speeds were slow here (˜seconds) due to the mechanical-evacuation rate and size of our chamber, the small nanoscale volume of these hollow semiconductors can enable much higher switching speeds, limited by the rate of adsorption/desorption of molecules at semiconductor interfaces. These chemical-gating effects are completely reversible, additive between different chemical compositions, and can enable semiconductor nanoelectronic devices for ‘chemical transistors’, ‘chemical diodes’, and very high-efficiency sensing applications.

A Carbon Nanotube-based NEMS Parametric Amplifier for Enhanced Radio Wave Detection and Electronic Signal Amplification

Energy Technology Data Exchange (ETDEWEB)

Aleman, B J; Sussman, A; Zettl, A [Physics Department, University of California, Berkeley, CA 94720 (United States); Mickelson, W, E-mail: azettl@berkeley.edu [Center of Integrated Nanomechanical Systems, University of California, Berkeley, CA 94720 (United States)

2011-07-20

We propose a scheme for a parametric amplifier based on a single suspended carbon nanotube field-emitter. This novel electromechanical nanotube device acts as a phase-sensitive, variable-gain, band-pass-filtering amplifier for electronic signal processing and, at the same time, can operate as a variable-sensitivity, tuneable detector and transducer of radio frequency electromagnetic waves. The amplifier can exhibit infinite gain at pumping voltages much less than 10 Volts. Additionally, the amplifier's low overhead power consumption (10-1000 nW) make it exceptionally attractive for ultra-low-power applications.

A Carbon Nanotube-based NEMS Parametric Amplifier for Enhanced Radio Wave Detection and Electronic Signal Amplification

International Nuclear Information System (INIS)

Aleman, B J; Sussman, A; Zettl, A; Mickelson, W

2011-01-01

We propose a scheme for a parametric amplifier based on a single suspended carbon nanotube field-emitter. This novel electromechanical nanotube device acts as a phase-sensitive, variable-gain, band-pass-filtering amplifier for electronic signal processing and, at the same time, can operate as a variable-sensitivity, tuneable detector and transducer of radio frequency electromagnetic waves. The amplifier can exhibit infinite gain at pumping voltages much less than 10 Volts. Additionally, the amplifier's low overhead power consumption (10-1000 nW) make it exceptionally attractive for ultra-low-power applications.

Proposal for multiple-valued logic in gated semiconducting carbon nanotubes

Science.gov (United States)

Dragoman, D.; Dragoman, M.

2006-06-01

The proposal for an implementation of multi-valued logical devices based on excited states of a single quantum well is analysed for various configurations of carbon nanotube quantum wells, which were already experimentally demonstrated at room temperature. The best configuration, which gathers all the advantages of multi-valued logic, is a gated carbon nanotube device where the quantum well is imprinted via DC voltages applied on gate electrodes.

Fluidic Vectoring of a Planar Incompressible Jet Flow

Science.gov (United States)

Mendez, Miguel Alfonso; Scelzo, Maria Teresa; Enache, Adriana; Buchlin, Jean-Marie

2018-06-01

This paper presents an experimental, a numerical and a theoretical analysis of the performances of a fluidic vectoring device for controlling the direction of a turbulent, bi-dimensional and low Mach number (incompressible) jet flow. The investigated design is the co-flow secondary injection with Coanda surface, which allows for vectoring angles up to 25° with no need of moving mechanical parts. A simple empirical model of the vectoring process is presented and validated via experimental and numerical data. The experiments consist of flow visualization and image processing for the automatic detection of the jet centerline; the numerical simulations are carried out solving the Unsteady Reynolds Average Navier- Stokes (URANS) closed with the k - ω SST turbulence model, using the PisoFoam solver from OpenFOAM. The experimental validation on three different geometrical configurations has shown that the model is capable of providing a fast and reliable evaluation of the device performance as a function of the operating conditions.

Carbon nanotube based functional superhydrophobic coatings

Science.gov (United States)

Sethi, Sunny

The main objective of this dissertation is synthesis of carbon nanotube (CNT) based superhydrophobic materials. The materials were designed such that electrical and mechanical properties of CNTs could be combined with superhydrophobicity to create materials with unique properties, such as self-cleaning adhesives, miniature flotation devices, ice-repellant coatings, and coatings for heat transfer furnaces. The coatings were divided into two broad categories based on CNT structure: Vertically aligned CNT arrays (VA coatings) and mesh-like (non-aligned) carbon nanotube arrays (NA coatings). VA coatings were used to create self-cleaning adhesives and flexible field emission devices. Coatings with self cleaning property along with high adhesiveness were inspired from structure found on gecko foot. Gecko foot is covered with thousands of microscopic hairs called setae; these setae are further divided into hundreds of nanometer sized hairs called spatulas. When gecko presses its foot against any surface, these hairs bend and conform to the topology of the surface resulting into very large area of contact. Such large area of intimate contact allows geckos to adhere to surfaces using van der Waals (vdW) interactions alone. VA-CNTs adhere to a variety of surfaces using a similar mechanism. CNTs of suitable diameter could withstand four times higher adhesion force than gecko foot. We found that upon soiling these CNT based adhesives (gecko tape) could be cleaned using a water droplet (lotus effect) or by applying vibrations. These materials could be used for applications requiring reversible adhesion. VA coatings were also used for developing field emission devices. A single CNT can emit electrons at very low threshold voltages. Achieving efficient electron emission on large scale has a lot of challenges such as screening effect, pull-off and lower current efficiency. We have explored the use of polymer-CNT composite structures to overcome these challenges in this work. NA

Vertically aligned carbon nanotubes for microelectrode arrays applications.

Science.gov (United States)

Castro Smirnov, J R; Jover, Eric; Amade, Roger; Gabriel, Gemma; Villa, Rosa; Bertran, Enric

2012-09-01

In this work a methodology to fabricate carbon nanotube based electrodes using plasma enhanced chemical vapour deposition has been explored and defined. The final integrated microelectrode based devices should present specific properties that make them suitable for microelectrode arrays applications. The methodology studied has been focused on the preparation of highly regular and dense vertically aligned carbon nanotube (VACNT) mat compatible with the standard lithography used for microelectrode arrays technology.

Fluidic origami with embedded pressure dependent multi-stability: a plant inspired innovation.

Science.gov (United States)

Li, Suyi; Wang, K W

2015-10-06

Inspired by the impulsive movements in plants, this research investigates the physics of a novel fluidic origami concept for its pressure-dependent multi-stability. In this innovation, fluid-filled tubular cells are synthesized by integrating different Miura-Ori sheets into a three-dimensional topological system, where the internal pressures are strategically controlled similar to the motor cells in plants. Fluidic origami incorporates two crucial physiological features observed in nature: one is distributed, pressurized cellular organization, and the other is embedded multi-stability. For a single fluidic origami cell, two stable folding configurations can coexist due to the nonlinear relationships among folding, crease material deformation and internal volume change. When multiple origami cells are integrated, additional multi-stability characteristics could occur via the interactions between pressurized cells. Changes in the fluid pressure can tailor the existence and shapes of these stable folding configurations. As a result, fluidic origami can switch between being mono-stable, bistable and multi-stable with pressure control, and provide a rapid 'snap-through' type of shape change based on the similar principles as in plants. The outcomes of this research could lead to the development of new adaptive materials or structures, and provide insights for future plant physiology studies at the cellular level. © 2015 The Author(s).

FLUIDICS: THE ANSWER TO PROBLEMS OF HANDLING HAZARDOUS FLUIDS – A SURVEY

Czech Academy of Sciences Publication Activity Database

Tesař, Václav

2012-01-01

Roč. 2, č. 2 (2012), s. 167-183 ISSN 2041-9031 R&D Projects: GA ČR(CZ) GCP101/11/J019; GA TA ČR TA02020795 Institutional research plan: CEZ:AV0Z20760514 Keywords : fluidic pumps * fluidics * fluidic valves Subject RIV: BK - Fluid Dynamics http://journals.witpress.com/journals.asp?iID=78#papers

Illuminating the future of silicon photonics: optical coupling of carbon nanotubes to microrings

International Nuclear Information System (INIS)

Kato, Y K

2015-01-01

Advances in carbon nanotube material quality and processing techniques have led to an increased interest in nanotube photonics. In particular, emission in the telecommunication wavelengths makes nanotubes compatible with silicon photonics. Noury et al (2014 Nanotechnology 25 215201) have reported on carbon nanotube photoluminescence coupled to silicon microring resonators, underscoring the advantage of combining carbon nanotube emitters with silicon photonics. Their results open up the possibility of using nanotubes in other waveguide-based devices, taking advantage of well-established technologies. (viewpoint)

Resealable, optically accessible, PDMS-free fluidic platform for ex vivo interrogation of pancreatic islets.

Science.gov (United States)

Lenguito, Giovanni; Chaimov, Deborah; Weitz, Jonathan R; Rodriguez-Diaz, Rayner; Rawal, Siddarth A K; Tamayo-Garcia, Alejandro; Caicedo, Alejandro; Stabler, Cherie L; Buchwald, Peter; Agarwal, Ashutosh

2017-02-28

We report the design and fabrication of a robust fluidic platform built out of inert plastic materials and micromachined features that promote optimized convective fluid transport. The platform is tested for perfusion interrogation of rodent and human pancreatic islets, dynamic secretion of hormones, concomitant live-cell imaging, and optogenetic stimulation of genetically engineered islets. A coupled quantitative fluid dynamics computational model of glucose stimulated insulin secretion and fluid dynamics was first utilized to design device geometries that are optimal for complete perfusion of three-dimensional islets, effective collection of secreted insulin, and minimization of system volumes and associated delays. Fluidic devices were then fabricated through rapid prototyping techniques, such as micromilling and laser engraving, as two interlocking parts from materials that are non-absorbent and inert. Finally, the assembly was tested for performance using both rodent and human islets with multiple assays conducted in parallel, such as dynamic perfusion, staining and optogenetics on standard microscopes, as well as for integration with commercial perfusion machines. The optimized design of convective fluid flows, use of bio-inert and non-absorbent materials, reversible assembly, manual access for loading and unloading of islets, and straightforward integration with commercial imaging and fluid handling systems proved to be critical for perfusion assay, and particularly suited for time-resolved optogenetics studies.

Method for synthesis of titanium dioxide nanotubes using ionic liquids

Science.gov (United States)

Qu, Jun; Luo, Huimin; Dai, Sheng

2013-11-19

The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

Fluidics platform and method for sample preparation and analysis

Science.gov (United States)

Benner, W. Henry; Dzenitis, John M.; Bennet, William J.; Baker, Brian R.

2014-08-19

Herein provided are fluidics platform and method for sample preparation and analysis. The fluidics platform is capable of analyzing DNA from blood samples using amplification assays such as polymerase-chain-reaction assays and loop-mediated-isothermal-amplification assays. The fluidics platform can also be used for other types of assays and analyzes. In some embodiments, a sample in a sealed tube can be inserted directly. The following isolation, detection, and analyzes can be performed without a user's intervention. The disclosed platform may also comprises a sample preparation system with a magnetic actuator, a heater, and an air-drying mechanism, and fluid manipulation processes for extraction, washing, elution, assay assembly, assay detection, and cleaning after reactions and between samples.

Chemiresistor Devices for Chemical Warfare Agent Detection Based on Polymer Wrapped Single-Walled Carbon Nanotubes.

Science.gov (United States)

Fennell, John F; Hamaguchi, Hitoshi; Yoon, Bora; Swager, Timothy M

2017-04-28

Chemical warfare agents (CWA) continue to present a threat to civilian populations and military personnel in operational areas all over the world. Reliable measurements of CWAs are critical to contamination detection, avoidance, and remediation. The current deployed systems in United States and foreign militaries, as well as those in the private sector offer accurate detection of CWAs, but are still limited by size, portability and fabrication cost. Herein, we report a chemiresistive CWA sensor using single-walled carbon nanotubes (SWCNTs) wrapped with poly(3,4-ethylenedioxythiophene) (PEDOT) derivatives. We demonstrate that a pendant hexafluoroisopropanol group on the polymer that enhances sensitivity to a nerve agent mimic, dimethyl methylphosphonate, in both nitrogen and air environments to concentrations as low as 5 ppm and 11 ppm, respectively. Additionally, these PEDOT/SWCNT derivative sensor systems experience negligible device performance over the course of two weeks under ambient conditions.

Microbubble generator excited by fluidic oscillator's third harmonic frequency

Czech Academy of Sciences Publication Activity Database

Tesař, Václav

2014-01-01

Roč. 92, č. 9 (2014), s. 1603-1615 ISSN 0263-8762 R&D Projects: GA ČR GA13-23046S Institutional support: RVO:61388998 Keywords : fluidic oscillator * microbubble generation * fluidic feedback loop Subject RIV: BK - Fluid Dynamics Impact factor: 2.348, year: 2014 http://dx.doi.org/10.1016/j.cherd.2013.12.004

Micro-Fluidic Device for Drug Delivery

Science.gov (United States)

Beebe, David J. (Inventor); MacDonald, Michael J. (Inventor); Eddington, David T. (Inventor); Mensing, Glennys A. (Inventor)

2014-01-01

A microfluidic device is provided for delivering a drug to an individual. The microfluidic device includes a body that defines a reservoir for receiving the drug therein. A valve interconnects the reservoir to an output needle that is insertable into the skin of an individual. A pressure source urges the drug from the reservoir toward the needle. The valve is movable between a closed position preventing the flow of the drug from the reservoir to the output needle and an open position allowing for the flow of the drug from the reservoir to the output needle in response to a predetermined condition in the physiological fluids of the individual.

First-principles modeling of hafnia-based nanotubes.

Science.gov (United States)

Evarestov, Robert A; Bandura, Andrei V; Porsev, Vitaly V; Kovalenko, Alexey V

2017-09-15

Hybrid density functional theory calculations were performed for the first time on structure, stability, phonon frequencies, and thermodynamic functions of hafnia-based single-wall nanotubes. The nanotubes were rolled up from the thin free layers of cubic and tetragonal phases of HfO 2 . It was shown that the most stable HfO 2 single-wall nanotubes can be obtained from hexagonal (111) layer of the cubic phase. Phonon frequencies have been calculated for different HfO 2 nanolayers and nanotubes to prove the local stability and to find the thermal contributions to their thermodynamic functions. The role of phonons in stability of nanotubes seems to be negligible for the internal energy and noticeable for the Helmholtz free energy. Zone folding approach has been applied to estimate the connection between phonon modes of the layer and nanotubes and to approximate the nanotube thermodynamic properties. It is found that the zone-folding approximation is sufficiently accurate for heat capacity, but less accurate for entropy. The comparison has been done between the properties of TiO 2 , ZrO 2 , and HfO 2 . © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Investigation of the dye concentration influence on the lasing wavelength and threshold for a micro-fluidic dye laser

DEFF Research Database (Denmark)

Helbo, Bjarne; Kragh, Søren; Kjeldsen, B.G.

2003-01-01

We investigate a micro-fluidic dye laser, which can be integrated with polymer-based lab-on-a-chip microsystems without further processing steps. A simple rate-equation model is used to predict the lasing threshold. The laser device is characterised using the laser dye Rhodamine 6G dissolved...... in ethanol, and the influence of dye concentration on the lasing wavelength and threshold is investigated. The experiments confirm the predictions of the rate-equation model, that lasing can be achieved in the 10 mum long laser cavity with moderate concentrations of Rhodamine 6G in ethanol, starting from 5 x...

A photovoltaic self-powered gas sensor based on a single-walled carbon nanotube/Si heterojunction.

Science.gov (United States)

Liu, L; Li, G H; Wang, Y; Wang, Y Y; Li, T; Zhang, T; Qin, S J

2017-12-07

We present a novel photovoltaic self-powered gas sensor based on a p-type single-walled carbon nanotube (SWNT) and n-type silicon (n-Si) heterojunction. The energy from visible light suffices to drive the device owing to a built-in electric field (BEF) induced by the differences between the Fermi levels of SWNTs and n-Si.

Polypyrrole/titanium oxide nanotube arrays composites as an active material for supercapacitors.

Science.gov (United States)

Kim, Min Seok; Park, Jong Hyeok

2011-05-01

The authors present the first reported use of vertically oriented titanium oxide nanotube/polypyrrole (PPy) nanocomposites to increase the specific capacitance of TiO2 based energy storage devices. To increase their electrical storage capacity, titanium oxide nanotubes were coated with PPy and their morphologies were characterized. The incorporation of PPy increased the specific capacitance of the titanium oxide nanotube based supercapacitor system, due to their increased surface area and additional pseudo-capacitance.

Configurations of Fluidic Actuators for Generation of Hybrid-Synthetic Jets

Czech Academy of Sciences Publication Activity Database

Tesař, Václav

2007-01-01

Roč. 138, - (2007), s. 213-220 ISSN 0924-4247 R&D Projects: GA ČR GA101/07/1499 Institutional research plan: CEZ:AV0Z20760514 Keywords : synthetic jets * fluidics * fluidic alternators Subject RIV: BK - Fluid Dynamics Impact factor: 1.348, year: 2007

Porous Microfluidic Devices - Fabrication adn Applications

NARCIS (Netherlands)

de Jong, J.; Geerken, M.J.; Lammertink, Rob G.H.; Wessling, Matthias

2007-01-01

The major part of microfluidic devices nowadays consists of a dense material that defines the fluidic structure. A generic fabrication method enabling the production of completely porous micro devices with user-defined channel networks is developed. The channel walls can be used as a (selective)

New Fluidic-Oscillator Concept for Flow-Separation Control

Czech Academy of Sciences Publication Activity Database

Tesař, Václav; Zhong, S.; Rasheed, F.

2013-01-01

Roč. 51, č. 2 (2013), s. 397-405 ISSN 0001-1452 R&D Projects: GA ČR(CZ) GCP101/11/J019; GA TA ČR TA02020795; GA ČR GA13-23046S Institutional research plan: CEZ:AV0Z20760514 Institutional support: RVO:61388998 Keywords : fluidics * fluidic oscillator * resonator Subject RIV: BK - Fluid Dynamics Impact factor: 1.165, year: 2013 http://arc.aiaa.org/doi/abs/10.2514/1.J051791?journalCode=aiaaj

The Development of Computer Code for Safety Injection Tank (SIT) with Fluidic Device(FD) Blowdown Test

International Nuclear Information System (INIS)

Lee, Joo Hee; Kim, Tae Han; Choi, Hae Yun; Lee, Kwang Won; Chung, Chang Kyu

2007-01-01

Safety Injection Tanks (SITs) with the Fluidic Device (FD) of APR1400 provides a means of rapid reflooding of the core following a large break Loss Of Coolant Accident (LOCA), and keeping it covered until flow from the Safety Injection Pump (SIP) becomes available. A passive FD can provide two operation stages of a safety water injection into the RCS and allow more effective use of borated water in case of LOCA. Once a large break LOCA occurs, the system will deliver a high flow rate of cooling water for a certain period of time, and thereafter, the flow rate is reduced to a lower flow rate. The conventional computer code 'TURTLE' used to simulate the blowdown of OPR1000 SIT can not be directly applied to simulate a blowdown process of the SIT with FD. A new computer code is needed to be developed for the blowdown test evaluation of the APR1400 SIT with FD. Korea Power Engineering Company (KOPEC) has developed a new computer code to analyze the characteristics of the SIT with FD and validated the code through the comparison of the calculation results with the test results obtained by Ulchin 5 and 6 units pre-operational test and VAlve Performance Evaluation Rig (VAPER) tests performed by The Korea Atomic Energy Research Institute (KAERI)

A Recipe for Soft Fluidic Elastomer Robots.

Science.gov (United States)

Marchese, Andrew D; Katzschmann, Robert K; Rus, Daniela

2015-03-01

This work provides approaches to designing and fabricating soft fluidic elastomer robots. That is, three viable actuator morphologies composed entirely from soft silicone rubber are explored, and these morphologies are differentiated by their internal channel structure, namely, ribbed, cylindrical, and pleated. Additionally, three distinct casting-based fabrication processes are explored: lamination-based casting, retractable-pin-based casting, and lost-wax-based casting. Furthermore, two ways of fabricating a multiple DOF robot are explored: casting the complete robot as a whole and casting single degree of freedom (DOF) segments with subsequent concatenation. We experimentally validate each soft actuator morphology and fabrication process by creating multiple physical soft robot prototypes.

A study on the effect of fluidic device installed in a safety injection tank on thermal-hydraulic phenomena of large break loss of coolant accident

International Nuclear Information System (INIS)

Chung, Young Jong; Bae, Kyoo Hwan; Song, Jin Ho; Sim, Suk Ku; Park, Jong Kyun

1999-03-01

The performance of the Safety Injection Tank (SIT) with fluidic device (advanced SIT) is analyzed for the large break loss of coolant accident (LBLOCA) using RELAP5/MOD3.1-KREM. First the case is analyzed using the conventional SIT. Among various cases the case with 4-split downcomer, discharge coefficient Cd=0.6, MCP trip with reactor trip and break location of cold leg discharge side with the pressurizer is found to be the most limiting case. For the same condition, the advanced SIT results the similar PCT, however it can maintain adequately the liquid level in the downcomer. By changing the ECCS location from the current injection to the cold leg elevations, PCT is improved by 75 K. (Author). 6 refs., 4 tabs., 54 figs

Water transport inside carbon nanotubes mediated by phonon-induced oscillating friction.

Science.gov (United States)

Ma, Ming; Grey, François; Shen, Luming; Urbakh, Michael; Wu, Shuai; Liu, Jefferson Zhe; Liu, Yilun; Zheng, Quanshui

2015-08-01

The emergence of the field of nanofluidics in the last decade has led to the development of important applications including water desalination, ultrafiltration and osmotic energy conversion. Most applications make use of carbon nanotubes, boron nitride nanotubes, graphene and graphene oxide. In particular, understanding water transport in carbon nanotubes is key for designing ultrafiltration devices and energy-efficient water filters. However, although theoretical studies based on molecular dynamics simulations have revealed many mechanistic features of water transport at the molecular level, further advances in this direction are limited by the fact that the lowest flow velocities accessible by simulations are orders of magnitude higher than those measured experimentally. Here, we extend molecular dynamics studies of water transport through carbon nanotubes to flow velocities comparable with experimental ones using massive crowd-sourced computing power. We observe previously undetected oscillations in the friction force between water and carbon nanotubes and show that these oscillations result from the coupling between confined water molecules and the longitudinal phonon modes of the nanotube. This coupling can enhance the diffusion of confined water by more than 300%. Our results may serve as a theoretical framework for the design of new devices for more efficient water filtration and osmotic energy conversion devices.

Pulsatile fluidic pump demonstration and predictive model application

International Nuclear Information System (INIS)

Morgan, J.G.; Holland, W.D.

1986-04-01

Pulsatile fluidic pumps were developed as a remotely controlled method of transferring or mixing feed solutions. A test in the Integrated Equipment Test facility demonstrated the performance of a critically safe geometry pump suitable for use in a 0.1-ton/d heavy metal (HM) fuel reprocessing plant. A predictive model was developed to calculate output flows under a wide range of external system conditions. Predictive and experimental flow rates are compared for both submerged and unsubmerged fluidic pump cases

Purification of carbon nanotubes via selective heating

Science.gov (United States)

Rogers, John A.; Wilson, William L.; Jin, Sung Hun; Dunham, Simon N.; Xie, Xu; Islam, Ahmad; Du, Frank; Huang, Yonggang; Song, Jizhou

2017-11-21

The present invention provides methods for purifying a layer of carbon nanotubes comprising providing a precursor layer of substantially aligned carbon nanotubes supported by a substrate, wherein the precursor layer comprises a mixture of first carbon nanotubes and second carbon nanotubes; selectively heating the first carbon nanotubes; and separating the first carbon nanotubes from the second carbon nanotubes, thereby generating a purified layer of carbon nanotubes. Devices benefiting from enhanced electrical properties enabled by the purified layer of carbon nanotubes are also described.

Silicon micro-fluidic cooling for NA62 GTK pixel detectors

CERN Document Server

Romagnoli, G; Brunel, B; Catinaccio, A; Degrange, J; Mapelli, A; Morel, M; Noel, J; Petagna, P

2015-01-01

Silicon micro-channel cooling is being studied for efficient thermal management in application fields such as high power computing and 3D electronic integration. This concept has been introduced in 2010 for the thermal management of silicon pixel detectors in high energy physics experiments. Combining the versatility of standard micro-fabrication processes with the high thermal efficiency typical of micro-fluidics, it is possible to produce effective thermal management devices that are well adapted to different detector configurations. The production of very thin cooling devices in silicon enables a minimization of material of the tracking sensors and eliminates mechanical stresses due to the mismatch of the coefficient of thermal expansion between detectors and cooling systems. The NA62 experiment at CERN will be the first high particle physics experiment that will install a micro-cooling system to perform the thermal management of the three detection planes of its Gigatracker pixel detector.

Electrochemical device

Science.gov (United States)

Grimes, Patrick G.; Einstein, Harry; Bellows, Richard J.

1988-01-12

A tunnel protected electrochemical device features channels fluidically communicating between manifold, tunnels and cells. The channels are designed to provide the most efficient use of auxiliary power. The channels have a greater hydraulic pressure drop and electrical resistance than the manifold. This will provide a design with the optimum auxiliary energy requirements.

Benchmark and parametric study of a passive flow controller (fluidic device) for the development of optimal designs using a CFD code

International Nuclear Information System (INIS)

Lim, Sang-Gyu; Lee, Seok-Ho; Kim, Han-Gon

2010-01-01

A passive flow controller or a fluidic device (FD) is used for a safety injection system (SIS) for efficient use of nuclear reactor emergency cooling water since it can control the injection flow rate in a passive and optimal way. The performance of the FD is represented by pressure loss coefficient (K-factor) which is further affected by the configuration of the components such as a control port direction and a nozzle angle. The flow control mechanism that is varied according to the water level inside a vortex chamber determines the duration of the safety injection. This paper deals with a computational fluid dynamics (CFD) analysis for simulating the flow characteristics of the FD using the ANSYS CFX 11.0. The CFD analysis is benchmarked against existing experimental data to obtain applicability to the prediction of the FD performance in terms of K-factor. The CFD calculation is implemented with Shear Stress Transport (SST) model for a swirling flow and a strong streamline curvature in the vortex chamber of the FD, considering a numerical efficiency. Based on the benchmark results, parametric analyses are performed for an optimal design of the FD by varying the control port direction and the nozzle angle. Consequently, the FD performance is enhanced according to the angle of the control port nozzle.

Self Assembled Carbon Nanotube Enhanced Ultracapacitors, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The objective of this NASA STTR program is to develop single wall carbon nanotube (SWCNT) based ultracapacitors for energy storage devices (ESD) application, using...

Carbon nanotube woven textile photodetector

Science.gov (United States)

Zubair, Ahmed; Wang, Xuan; Mirri, Francesca; Tsentalovich, Dmitri E.; Fujimura, Naoki; Suzuki, Daichi; Soundarapandian, Karuppasamy P.; Kawano, Yukio; Pasquali, Matteo; Kono, Junichiro

2018-01-01

The increasing interest in mobile and wearable technology demands the enhancement of functionality of clothing through incorporation of sophisticated architectures of multifunctional materials. Flexible electronic and photonic devices based on organic materials have made impressive progress over the past decade, but higher performance, simpler fabrication, and most importantly, compatibility with woven technology are desired. Here we report on the development of a weaved, substrateless, and polarization-sensitive photodetector based on doping-engineered fibers of highly aligned carbon nanotubes. This room-temperature-operating, self-powered detector responds to radiation in an ultrabroad spectral range, from the ultraviolet to the terahertz, through the photothermoelectric effect, with a low noise-equivalent power (a few nW/Hz 1 /2) throughout the range and with a Z T -factor value that is twice as large as that of previously reported carbon nanotube-based photothermoelectric photodetectors. Particularly, we fabricated a ˜1 -m-long device consisting of tens of p+-p- junctions and weaved it into a shirt. This device demonstrated a collective photoresponse of the series-connected junctions under global illumination. The performance of the device did not show any sign of deterioration through 200 bending tests with a bending radius smaller than 100 μ m as well as standard washing and ironing cycles. This unconventional photodetector will find applications in wearable technology that require detection of electromagnetic radiation.

Fluidic pumps

International Nuclear Information System (INIS)

Priestman, G.H.

1990-01-01

A fluidic pump has primary and secondary vessels connected by a pipe, a displacement vessel having liquid to be delivered through a pipe via a rectifier provided with a feed tank. A drive unit delivers pressure fluid to a line to raise liquid and compress trapped gas or liquid in the space, including the pipe between the liquids in the two vessels and thus drive liquid out of the displacement vessel. The driving gas is therefore separated by the barrier liquid and the trapped gas or liquid from the liquid to be pumped which liquid could be e.g. radioactive. (author)

Photodetector based on carbon nanotubes

Science.gov (United States)

Pavlov, A.; Kitsyuk, E.; Ryazanov, R.; Timoshenkov, V.; Adamov, Y.

2015-09-01

Photodetector based on carbon nanotubes (CNT) was investigated. Sensors were done on quartz and silicon susbtrate. Samples of photodetectors sensors were produced by planar technology. This technology included deposition of first metal layer (Al), lithography for pads formation, etching, and formation of local catalyst area by inverse lithography. Vertically-aligned multi-wall carbon nanotubes were directly synthesized on substrate by PECVD method. I-V analysis and spectrum sensitivity of photodetector were investigated for 0.4 μm - 1.2 μm wavelength. Resistivity of CNT layers over temperature was detected in the range of -20°C to 100°C.

Metal-filled carbon nanotube based optical nanoantennas: bubbling, reshaping, and in situ characterization.

Science.gov (United States)

Fan, Zheng; Tao, Xinyong; Cui, Xudong; Fan, Xudong; Zhang, Xiaobin; Dong, Lixin

2012-09-21

Controlled fabrication of metal nanospheres on nanotube tips for optical antennas is investigated experimentally. Resembling soap bubble blowing using a straw, the fabrication process is based on nanofluidic mass delivery at the attogram scale using metal-filled carbon nanotubes (m@CNTs). Two methods have been investigated including electron-beam-induced bubbling (EBIB) and electromigration-based bubbling (EMBB). EBIB involves the bombardment of an m@CNT with a high energy electron beam of a transmission electron microscope (TEM), with which the encapsulated metal is melted and flowed out from the nanotube, generating a metallic particle on a nanotube tip. In the case where the encapsulated materials inside the CNT have a higher melting point than what the beam energy can reach, EMBB is an optional process to apply. Experiments show that, under a low bias (2.0-2.5 V), nanoparticles can be formed on the nanotube tips. The final shape and crystallinity of the nanoparticles are determined by the cooling rate. Instant cooling occurs with a relatively large heat sink and causes the instant shaping of the solid deposit, which is typically similar to the shape of the molten state. With a smaller heat sink as a probe, it is possible to keep the deposit in a molten state. Instant cooling by separating the deposit from the probe can result in a perfect sphere. Surface and volume plasmons characterized with electron energy loss spectroscopy (EELS) prove that resonance occurs between a pair of as-fabricated spheres on the tip structures. Such spheres on pillars can serve as nano-optical antennas and will enable devices such as scanning near-field optical microscope (SNOM) probes, scanning anodes for field emitters, and single molecule detectors, which can find applications in bio-sensing, molecular detection, and high-resolution optical microscopy.

High-performance thin-film-transistors based on semiconducting-enriched single-walled carbon nanotubes processed by electrical-breakdown strategy

Energy Technology Data Exchange (ETDEWEB)

Aïssa, B., E-mail: aissab@emt.inrs.ca [Centre Énergie, Matériaux et Télécommunications, INRS, 1650, boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Qatar Environment and Energy Research Institute (QEERI), Qatar Foundation, P.O. Box 5825, Doha (Qatar); Nedil, M. [Telebec Wireless Underground Communication Laboratory, UQAT, 675, 1" è" r" e Avenue, Val d’Or, Québec J9P 1Y3 (Canada); Habib, M.A. [Computer Sciences and Engineering Department, Yanbu University College, P.O. Box 30031 (Saudi Arabia); Abdul-Hafidh, E.H. [High Energy Physics Department, Yanbu University College, P.O. Box 30031 (Saudi Arabia); Rosei, F. [Centre Énergie, Matériaux et Télécommunications, INRS, 1650, boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada)

2015-02-15

Highlights: • We selectively burn metallic single wall carbon nanotubes (SWCNT) by electrical breakdown. • We successfully achieve a semiconducting enriched-SWCNT in TFT configuration. • High performance, like On/Off of 10{sup 5} and a subthreshold swing of 165 mV/decades were obtained. • After PMMA coating, the SWCNT–TFTs were found stables for more than 4 months. - Abstract: Over the past two decades, among remarkable variety of nanomaterials, single-walled carbon nanotubes (SWCNTs) remain the most intriguing and uniquely well suited materials for applications in high-performance electronics. The most advanced technologies require the ability to form purely semiconducting SWCNTs. Here, we report on our strategy based on the well known progressive electrical breakdown process that offer this capability and serves as highly efficient means for selectively removing metallic carbon nanotubes from electronically heterogeneous random networks, deposited on silicon substrates in a thin film transistor (TFT) configuration. We demonstrate the successful achievement of semiconducting enriched-SWCNT networks in TFT scheme that reach On/Off switching ratios of ∼100,000, on-conductance of 20 μS, and a subthreshold swing of less than 165 mV/decades. The obtained TFT devices were then protected with thin film poly(methyl methacrylate) (PMMA) to keep the percolation level of the SWCNTs network spatially and temporally stable, while protecting it from atmosphere exchanges. TFT devices were found to be air-stable and maintained their excellent characteristics in ambient atmosphere for more than 4 months. This approach could work as a platform for future nanotube-based nanoelectronics.

Molecular Weiss domain polarization in piezoceramics to diaphragm, cantilever and channel construction in low-temperature-cofired ceramics for micro-fluidic applications

International Nuclear Information System (INIS)

Khanna, P.K.; Ahmad, S.; Grimme, R.

2005-01-01

This paper presents the efforts made to study the process of comminution to Weiss domain polarization and phase transition in piezoceramics together with the versatility of low-temperature-cofired ceramics-based devices and components for their ready adoption for typical applications in the area of micro-fluidics. A conceptual micro-fluidic module has been presented and few unit entities necessary for its realization have been described. The purpose of these entities is to position the sensors and actuators by using piezoelectric materials. Investigations are performed to make useful constructions like diaphragms and cantilevers for laying the sensing elements, cavities for burying the electronic chip devices, and channels for fluid transportation. In order to realize these constructions, the basic step involves machining of circular, straight line, rectangular and square-shaped structure in the green ceramic tapes followed by lamination and firing with post-machining in some cases. The diaphragm and cavity includes one or more un-machined layer stacked together with several machined layers with rectangular or square slits. The cantilever is an extension of the diaphragm creation process with inclusion of a post-machining step. The channel essentially consists of a machined green ceramic layer sandwiched between an un-machined and a partially machined layer. The fabrication for all the above constructions has been exemplified and the details have been discussed

Modelling the relative stability of carbon nanotubes exposed to environmental adsorbates and air

International Nuclear Information System (INIS)

Barnard, Amanda S

2009-01-01

In parallel with the development of technological applications for carbon nanotubes, issues related to toxicology and environmental impact are also under increased scrutiny. It is clear from the available literature that the integrity of future carbon nanotube-based devices, our ability to anticipate failure of these devices, and our ability to manage the toxicological and environmental impacts require a detailed understanding of the stability of pure and functionalized carbon nanotubes under a full range of environmental conditions. Motivated by this endeavour, the present study uses a general thermodynamic model to predict the relative stability of carbon nanotubes exposed to a variety of atmospheric adsorbates, and uses them to examine the stability of nanotubes in air, as a function of the relative humidity. In general the results indicate that the adsorption of a sparse coverage of air is thermodynamically favoured, depending on the humidity, and the stability of small diameter nanotubes may be improved by exposure to humid air.

Growth of nanotubes and chemical sensor applications

Science.gov (United States)

Hone, James; Kim, Philip; Huang, X. M. H.; Chandra, B.; Caldwell, R.; Small, J.; Hong, B. H.; Someya, T.; Huang, L.; O'Brien, S.; Nuckolls, Colin P.

2004-12-01

We have used a number of methods to grow long aligned single-walled carbon nanotubes. Geometries include individual long tubes, dense parallel arrays, and long freely suspended nanotubes. We have fabricated a variety of devices for applications such as multiprobe resistance measurement and high-current field effect transistors. In addition, we have measured conductance of single-walled semiconducting carbon nanotubes in field-effect transistor geometry and investigated the device response to water and alcoholic vapors. We observe significant changes in FET drain current when the device is exposed to various kinds of different solvent. These responses are reversible and reproducible over many cycles of vapor exposure. Our experiments demonstrate that carbon nanotube FETs are sensitive to a wide range of solvent vapors at concentrations in the ppm range.

Dispersability of Carbon Nanotubes in Biopolymer-Based Fluids

Directory of Open Access Journals (Sweden)

Franco Tardani

2015-01-01

Full Text Available In this review the dispersability of carbon nanotubes in aqueous solutions containing proteins, or nucleic acids, is discussed. Data reported previously are complemented by unpublished ones. In the mentioned nanotube-based systems several different phases are observed, depending on the type and concentration of biopolymer, as well as the amount of dispersed nanotubes. The phase behavior depends on how much biopolymers are adsorbing, and, naturally, on the molecular details of the adsorbents. Proper modulation of nanotube/biopolymer interactions helps switching between repulsive and attractive regimes. Dispersion or phase separation take place, respectively, and the formation of liquid crystalline phases or gels may prevail with respect to dispersions. We report on systems containing ss-DNA- and lysozyme-stabilized nanotubes, representative of different organization modes. In the former case, ss-DNA rolls around CNTs and ensures complete coverage. Conversely, proteins randomly and non-cooperatively adsorb onto nanotubes. The two functionalization mechanisms are significantly different. A fine-tuning of temperature, added polymer, pH, and/or ionic strength conditions induces the formation of a given supra-molecular organization mode. The biopolymer physico-chemical properties are relevant to induce the formation of different phases made of carbon nanotubes.

Rotational actuator of motor based on carbon nanotubes

Science.gov (United States)

Zettl, Alexander K.; Fennimore, Adam M.; Yuzvinsky, Thomas D.

2008-11-18

A rotational actuator/motor based on rotation of a carbon nanotube is disclosed. The carbon nanotube is provided with a rotor plate attached to an outer wall, which moves relative to an inner wall of the nanotube. After deposit of a nanotube on a silicon chip substrate, the entire structure may be fabricated by lithography using selected techniques adapted from silicon manufacturing technology. The structures to be fabricated may comprise a multiwall carbon nanotube (MWNT), two in plane stators S1, S2 and a gate stator S3 buried beneath the substrate surface. The MWNT is suspended between two anchor pads and comprises a rotator attached to an outer wall and arranged to move in response to electromagnetic inputs. The substrate is etched away to allow the rotor to freely rotate. Rotation may be either in a reciprocal or fully rotatable manner.

Quantum transport in carbon nanotubes

DEFF Research Database (Denmark)

Laird, Edward A.; Kuemmeth, Ferdinand; Steele, Gary A.

2015-01-01

Carbon nanotubes are a versatile material in which many aspects of condensed matter physics come together. Recent discoveries, enabled by sophisticated fabrication, have uncovered new phenomena that completely change our understanding of transport in these devices, especially the role of the spin...... blockade. This can be exploited to read out spin and valley qubits, and to measure the decay of these states through coupling to nuclear spins and phonons. A second unique property of carbon nanotubes is that the combination of valley freedom and electron-electron interactions in one dimension strongly...... and valley degrees of freedom. This review describes the modern understanding of transport through nanotube devices. Unlike conventional semiconductors, electrons in nanotubes have two angular momentum quantum numbers, arising from spin and from valley freedom. We focus on the interplay between the two...

Carbon nanotube and graphene device modeling and simulation

Science.gov (United States)

Yoon, Young Ki

The performance of the semiconductors has been improved and the price has gone down for decades. It has been continuously scaled down in size year by year, and now it encounters the fundamental scaling limit. We, therefore, should prepare a new era beyond the conventional semiconductor technologies. One of the most promising devices is possible by carbon nanotube (CNT) or graphene nanoribbon (GNR) in terms of its excellent charge transport properties. Their fundamental material properties and device physics are totally different to those of the conventional devices. In this nano-regime, more sophisticated device modeling and simulation are really needed to elucidate nano-device operation and to save our resources from errors. The numerical simulation works in this dissertation will provide novel view points on the emerging devices. In this dissertation, CNT and GNR devices are numerically studied. The first part of this work is on CNT devices, and a common structure of CNT device has CNT channel, metal source and drain contacts, and gate electrode. We investigate the strain, geometry, and scattering effects on the device performance of CNT field-effect transistors (FETs). It is shown that even a small amount of strain can result in a large effect on the performance of CNTFETs due to the variation of the bandgap and band-structure-limited velocity. A type of strain which produces a larger bandgap results in increased Schottky barrier (SB) height and decreased band-structure-limited velocity, and hence a smaller minimum leakage current, smaller on current, larger maximum achievable Ion/Ioff, and larger intrinsic delay. We also examine geometry effect of partial gate CNTFETs. In the growth process of vertical CNT, underlap between the gate and the bottom electrode is advantageous for transistor operation because it suppresses ambipolar conduction of SBFETs. Both n-type and p-type transistor operations with balanced performance metrics can be achieved on a single

Compressible flow in fluidic oscillators

Science.gov (United States)

Graff, Emilio; Hirsch, Damian; Gharib, Mory

2013-11-01

We present qualitative observations on the internal flow characteristics of fluidic oscillator geometries commonly referred to as sweeping jets in active flow control applications. We also discuss the effect of the geometry on the output jet in conditions from startup to supersonic exit velocity. Supported by the Boeing Company.

Numerical simulations on increasing turbojet engines exhaust mixture ratio using fluidic chevrons

Directory of Open Access Journals (Sweden)

Adrian GRUZEA

2017-06-01

Full Text Available This paper refers to some aspects regarding the terms “chevron” and “fluidic chevron” and to the process of increasing the jet engines exhaust mixing rate towards achieving noise reduction. One of the noise reduction methods consists in covering the high velocity main flow with a secondary one, having a much lower velocity, similar to the turbofan engines. The fluidic chevrons try to accomplish these requirements, being used just in particular moments of the flight. This study will be based on numerical simulations carried using the commercial software ANSYS. The geometry used will the based on the micro jet engine JetCat P80, equipping the turbines laboratory from the Faculty of Aerospace Engineering. A research based on the measured geometric, gasodynamic and cinematic parameters will be carried varying the mass flow and keeping the immersion angle constant. As a result of these simulations we’ll observe the influence of the mentioned parameters on the jet’s flow field.

Carbon nanotube-based black coatings

Science.gov (United States)

Lehman, J.; Yung, C.; Tomlin, N.; Conklin, D.; Stephens, M.

2018-03-01

Coatings comprising carbon nanotubes are very black, that is, characterized by uniformly low reflectance over a broad range of wavelengths from the visible to far infrared. Arguably, there is no other material that is comparable. This is attributable to the intrinsic properties of graphitic material as well as the morphology (density, thickness, disorder, and tube size). We briefly describe a history of other coatings such as nickel phosphorous, gold black, and carbon-based paints and the comparable structural morphology that we associate with very black coatings. The need for black coatings is persistent for a variety of applications ranging from baffles and traps to blackbodies and thermal detectors. Applications for space-based instruments are of interest and we present a review of space qualification and the results of outgassing measurements. Questions of nanoparticle safety depend on the nanotube size and aspect ratio as well as the nature and route of exposure. We describe the growth of carbon nanotube forests along with the catalyst requirements and temperature limitations. We also describe coatings derived from carbon nanotubes and applied like paint. Building the measurement apparatus and determining the optical properties of something having negligible reflectance are challenging and we summarize the methods and means for such measurements. There exists information in the literature for effective media approximations to model the dielectric function of vertically aligned arrays. We summarize this along with the refractive index of graphite from the literature that is necessary for modeling the optical properties. In our experience, the scientific questions can be overshadowed by practical matters, so we provide an appendix of recipes for making as-grown and sprayed coatings along with an example of reflectance measurements.

Thermal Dissipation Efficiency in a Micro-Processor Using Carbon Nanotubes Based Composite

Science.gov (United States)

Thang, Bui Hung; Van Quang, Cao; Nghia, Van Trong; Hong, Phan Ngoc; Van Chuc, Nguyen; Tam, Ngo Thi Thanh; Quang, Le Dinh; Khang, Dao Duc; Khoi, Phan Hong; Minh, Phan Ngoc

2009-09-01

Modern electronic and optoelectronic devices such as μ-processor, light emitting diode, semiconductor laser issued a challenge in the thermal dissipation problem. Finding an effective way for thermal dissipation therefore becomes a very important issue. It is known that carbon nanotubes (CNTs) is one of the most valuable materials with high thermal conductivity (2000 W/m.K compared to thermal conductivity of Ag 419 W/m.K). This suggested an approach in applying the CNTs as an essential component for thermal dissipation media to improve the performance of computer processor and other high power electronic devices. In this work multi walled carbon nanotubes (MWCNTs) based composites were utilized as the thermal dissipation media in a micro processor of a personal computer. The MWCNTs of different concentrations were added into polyaniline, commercial silicon thermal paste and commercial silver thermal paste by mechanical methods. A personal computer with configuration: Intel Pentium IV 3.066 GHz, 512 MB of RAM and Windows XP Service Pack 2 Operating System was employed. The thermal dissipation efficiency of the system was evaluated by directly measure the temperature of the μ-processor during the operation of the computer in different CPU speeds. The measured results showed that the CNTs based composite could reduce the temperature of the u-processor more than 5° C, and the time for increasing the temperature of the μ-processor was three times longer than that when using commercial thermal paste.

Iron oxide nanotubes synthesized via template-based electrodeposition

Science.gov (United States)

Lim, Jin-Hee; Min, Seong-Gi; Malkinski, Leszek; Wiley, John B.

2014-04-01

Considerable effort has been invested in the development of synthetic methods for the preparation iron oxide nanostructures for applications in nanotechnology. While a variety of structures have been reported, only a few studies have focused on iron oxide nanotubes. Here, we present details on the synthesis and characterization of iron oxide nanotubes along with a proposed mechanism for FeOOH tube formation. The FeOOH nanotubes, fabricated via a template-based electrodeposition method, are found to exhibit a unique inner-surface. Heat treatment of these tubes under oxidizing or reducing atmospheres can produce either hematite (α-Fe2O3) or magnetite (Fe3O4) structures, respectively. Hematite nanotubes are composed of small nanoparticles less than 20 nm in diameter and the magnetization curves and FC-ZFC curves show superparamagnetic properties without the Morin transition. In the case of magnetite nanotubes, which consist of slightly larger nanoparticles, magnetization curves show ferromagnetism with weak coercivity at room temperature, while FC-ZFC curves exhibit the Verwey transition at 125 K.Considerable effort has been invested in the development of synthetic methods for the preparation iron oxide nanostructures for applications in nanotechnology. While a variety of structures have been reported, only a few studies have focused on iron oxide nanotubes. Here, we present details on the synthesis and characterization of iron oxide nanotubes along with a proposed mechanism for FeOOH tube formation. The FeOOH nanotubes, fabricated via a template-based electrodeposition method, are found to exhibit a unique inner-surface. Heat treatment of these tubes under oxidizing or reducing atmospheres can produce either hematite (α-Fe2O3) or magnetite (Fe3O4) structures, respectively. Hematite nanotubes are composed of small nanoparticles less than 20 nm in diameter and the magnetization curves and FC-ZFC curves show superparamagnetic properties without the Morin transition

Device and circuit-level performance of carbon nanotube field-effect transistor with benchmarking against a nano-MOSFET.

Science.gov (United States)

Tan, Michael Loong Peng; Lentaris, Georgios; Amaratunga Aj, Gehan

2012-08-19

The performance of a semiconducting carbon nanotube (CNT) is assessed and tabulated for parameters against those of a metal-oxide-semiconductor field-effect transistor (MOSFET). Both CNT and MOSFET models considered agree well with the trends in the available experimental data. The results obtained show that nanotubes can significantly reduce the drain-induced barrier lowering effect and subthreshold swing in silicon channel replacement while sustaining smaller channel area at higher current density. Performance metrics of both devices such as current drive strength, current on-off ratio (Ion/Ioff), energy-delay product, and power-delay product for logic gates, namely NAND and NOR, are presented. Design rules used for carbon nanotube field-effect transistors (CNTFETs) are compatible with the 45-nm MOSFET technology. The parasitics associated with interconnects are also incorporated in the model. Interconnects can affect the propagation delay in a CNTFET. Smaller length interconnects result in higher cutoff frequency.

Silicon spectral response extension through single wall carbon nanotubes in hybrid solar cells

KAUST Repository

Del Gobbo, Silvano; Castrucci, P.; Fedele, S.; Riele, L.; Convertino, A.; Morbidoni, M.; De Nicola, F.; Scarselli, M.; Camilli, L.; De Crescenzi, M.

2013-01-01

Photovoltaic devices based on single wall carbon nanotubes (SWCNTs) and n-silicon multiple heterojunctions have been fabricated by a SWCNT film transferring process. We report on the ability of the carbon nanotubes to extend the Si spectral range towards the near ultraviolet (UV) and the near infrared regions. Semiconducting and about metallic SWCNT networks have been studied as a function of the film sheet resistance, Rsh. Optical absorbance and Raman spectroscopy have been used to assign nanotube chirality and electronic character. This gave us hints of evidence of the participation of the metal nanotubes in the photocurrent generation. Moreover, we provide evidence that the external quantum efficiency spectral range can be modulated as a function of the SWCNT network sheet resistance in a hybrid SWCNT/Si solar cell. This result will be very useful to further design/optimize devices with improved performance in spectral regions generally not covered by conventional Si p-n devices. © 2013 The Royal Society of Chemistry.

Performance Analysis of a Fluidic Axial Oscillation Tool for Friction Reduction with the Absence of a Throttling Plate

Directory of Open Access Journals (Sweden)

Xinxin Zhang

2017-04-01

Full Text Available An axial oscillation tool is proved to be effective in solving problems associated with high friction and torque in the sliding drilling of a complex well. The fluidic axial oscillation tool, based on an output-fed bistable fluidic oscillator, is a type of axial oscillation tool which has become increasingly popular in recent years. The aim of this paper is to analyze the dynamic flow behavior of a fluidic axial oscillation tool with the absence of a throttling plate in order to evaluate its overall performance. In particular, the differences between the original design with a throttling plate and the current default design are profoundly analyzed, and an improvement is expected to be recorded for the latter. A commercial computational fluid dynamics code, Fluent, was used to predict the pressure drop and oscillation frequency of a fluidic axial oscillation tool. The results of the numerical simulations agree well with corresponding experimental results. A sufficient pressure pulse amplitude with a low pressure drop is desired in this study. Therefore, a relative pulse amplitude of pressure drop and displacement are introduced in our study. A comparison analysis between the two designs with and without a throttling plate indicates that when the supply flow rate is relatively low or higher than a certain value, the fluidic axial oscillation tool with a throttling plate exhibits a better performance; otherwise, the fluidic axial oscillation tool without a throttling plate seems to be a preferred alternative. In most of the operating circumstances in terms of the supply flow rate and pressure drop, the fluidic axial oscillation tool performs better than the original design.

CMOS-based carbon nanotube pass-transistor logic integrated circuits

Science.gov (United States)

Ding, Li; Zhang, Zhiyong; Liang, Shibo; Pei, Tian; Wang, Sheng; Li, Yan; Zhou, Weiwei; Liu, Jie; Peng, Lian-Mao

2012-01-01

Field-effect transistors based on carbon nanotubes have been shown to be faster and less energy consuming than their silicon counterparts. However, ensuring these advantages are maintained for integrated circuits is a challenge. Here we demonstrate that a significant reduction in the use of field-effect transistors can be achieved by constructing carbon nanotube-based integrated circuits based on a pass-transistor logic configuration, rather than a complementary metal-oxide semiconductor configuration. Logic gates are constructed on individual carbon nanotubes via a doping-free approach and with a single power supply at voltages as low as 0.4 V. The pass-transistor logic configurarion provides a significant simplification of the carbon nanotube-based circuit design, a higher potential circuit speed and a significant reduction in power consumption. In particular, a full adder, which requires a total of 28 field-effect transistors to construct in the usual complementary metal-oxide semiconductor circuit, uses only three pairs of n- and p-field-effect transistors in the pass-transistor logic configuration. PMID:22334080

Fluorescently labeled bionanotransporters of nucleic acid based on carbon nanotubes

International Nuclear Information System (INIS)

Novopashina, D.S.; Apartsin, E.K.; Venyaminova, A.G.

2012-01-01

We propose an approach to the design of a new type of hybrids of oligonucleotides with fluorescein-functionalized single-walled carbon nanotubes. The approach is based on stacking interactions of functionalized nanotubes with pyrene residues in conjugates of oligonucleotides. The amino- and fluorescein-modified single walled carbon nanotubes are obtained, and their physico-chemical properties are investigated. The effect of the functionalization type of carbon nanotubes on the efficacy of the sorption of pyrene conjugates of oligonucleotides was examined. The proposed noncovalent hybrids of fluorescein-labeled carbon nanotubes with oligonucleotides may be used for the intracellular transport of functional nucleic acids.

Screen printed paper-based diagnostic devices with polymeric inks.

Science.gov (United States)

Sun, Ju-Yen; Cheng, Chao-Min; Liao, Ying-Chih

2015-01-01

A simple and low-cost fabrication method for paper-based diagnostic devices (PBDDs) is described in this study. Street-available polymer solutions were screen printed onto filter papers to create hydrophobic patterns for fluidic channels. In order to obtain fully functional hydrophobic patterns for fluids, the original polymer solutions were diluted with butyl acetate to yield a suitable viscosity range between 30-200 cP for complete patterning on paper. Typical pH and glucose tests with color indicators were performed on the screen printed PBDDs. Images of the PBDDs were analyzed by computers to obtain calibration curves for pH between 2 and 12 and glucose concentration ranging from 10-1000 mmol dm(-3). Detection of formaldehyde in acetone was also carried out to show the possibility of using this PBBD for analytical detection with organic solvents. An exemplar PBDD with simultaneous pH and glucose detection was also used to demonstrate the feasibility of applying this technique for realistic diagnostic applications.

Three-dimensional hot electron photovoltaic device with vertically aligned TiO2 nanotubes.

Science.gov (United States)

Goddeti, Kalyan C; Lee, Changhwan; Lee, Young Keun; Park, Jeong Young

2018-05-09

Titanium dioxide (TiO 2 ) nanotubes with vertically aligned array structures show substantial advantages in solar cells as an electron transport material that offers a large surface area where charges travel linearly along the nanotubes. Integrating this one-dimensional semiconductor material with plasmonic metals to create a three-dimensional plasmonic nanodiode can influence solar energy conversion by utilizing the generated hot electrons. Here, we devised plasmonic Au/TiO 2 and Ag/TiO 2 nanodiode architectures composed of TiO 2 nanotube arrays for enhanced photon absorption, and for the subsequent generation and capture of hot carriers. The photocurrents and incident photon to current conversion efficiencies (IPCE) were obtained as a function of photon energy for hot electron detection. We observed enhanced photocurrents and IPCE using the Ag/TiO 2 nanodiode. The strong plasmonic peaks of the Au and Ag from the IPCE clearly indicate an enhancement of the hot electron flux resulting from the presence of surface plasmons. The calculated electric fields and the corresponding absorbances of the nanodiode using finite-difference time-domain simulation methods are also in good agreement with the experimental results. These results show a unique strategy of combining a hot electron photovoltaic device with a three-dimensional architecture, which has the clear advantages of maximizing light absorption and a metal-semiconductor interface area.

Influence of the contact geometry on single-walled carbon nanotube/Si photodetector response

Science.gov (United States)

Scagliotti, Mattia; Salvato, Matteo; De Crescenzi, Maurizio; Boscardin, Maurizio; Castrucci, Paola

2018-03-01

A systematic study of the optical response of photodetectors based on carbon nanotube/Si heterojunctions is performed by measuring the responsivity, the detectivity and the time response of the devices with different contact configurations. The sensors are obtained by dry transferring single-walled carbon nanotube films on the surface of n-doped Si substrate provided with a multifinger contact geometry. The experimental data show a consistent improvement of the photodetector parameters with the increase of the number of fingers without affecting the carbon nanotube film thickness for increase its optical transmittance as in previous experiments. The role of the electrical resistance of the carbon nanotube film is discussed. The obtained results confirm the method and suggest new perspectives in the use of nanostructured materials as part of semiconducting optical devices.

Selective Deposition and Alignment of Single-Walled Carbon Nanotubes Assisted by Dielectrophoresis: From Thin Films to Individual Nanotubes

Science.gov (United States)

Li, Pengfei; Xue, Wei

2010-06-01

Dielectrophoresis has been used in the controlled deposition of single-walled carbon nanotubes (SWNTs) with the focus on the alignment of nanotube thin films and their applications in the last decade. In this paper, we extend the research from the selective deposition of SWNT thin films to the alignment of small nanotube bundles and individual nanotubes. Electrodes with “teeth”-like patterns are fabricated to study the influence of the electrode width on the deposition and alignment of SWNTs. The entire fabrication process is compatible with optical lithography-based techniques. Therefore, the fabrication cost is low, and the resulting devices are inexpensive. A series of SWNT solutions is prepared with concentrations ranging from 0.0125 to 0.2 mg/ml. The alignment of SWNT thin films, small bundles, and individual nanotubes is achieved under the optimized experimental conditions. The electrical properties of these samples are characterized; the linear current-voltage plots prove that the aligned SWNTs are mainly metallic nanotubes. The microscopy inspection of the samples demonstrates that the alignment of small nanotube bundles and individual nanotubes can only be achieved using narrow electrodes and low-concentration solutions. Our investigation shows that it is possible to deposit a controlled amount of SWNTs in desirable locations using dielectrophoresis.

Selective Deposition and Alignment of Single-Walled Carbon Nanotubes Assisted by Dielectrophoresis: From Thin Films to Individual Nanotubes

Directory of Open Access Journals (Sweden)

Li Pengfei

2010-01-01

Full Text Available Abstract Dielectrophoresis has been used in the controlled deposition of single-walled carbon nanotubes (SWNTs with the focus on the alignment of nanotube thin films and their applications in the last decade. In this paper, we extend the research from the selective deposition of SWNT thin films to the alignment of small nanotube bundles and individual nanotubes. Electrodes with “teeth”-like patterns are fabricated to study the influence of the electrode width on the deposition and alignment of SWNTs. The entire fabrication process is compatible with optical lithography-based techniques. Therefore, the fabrication cost is low, and the resulting devices are inexpensive. A series of SWNT solutions is prepared with concentrations ranging from 0.0125 to 0.2 mg/ml. The alignment of SWNT thin films, small bundles, and individual nanotubes is achieved under the optimized experimental conditions. The electrical properties of these samples are characterized; the linear current–voltage plots prove that the aligned SWNTs are mainly metallic nanotubes. The microscopy inspection of the samples demonstrates that the alignment of small nanotube bundles and individual nanotubes can only be achieved using narrow electrodes and low-concentration solutions. Our investigation shows that it is possible to deposit a controlled amount of SWNTs in desirable locations using dielectrophoresis.

Activated carbon and single-walled carbon nanotube based electrochemical capacitor in 1 M LiPF6 electrolyte

International Nuclear Information System (INIS)

Azam, M.A.; Jantan, N.H.; Dorah, N.; Seman, R.N.A.R.; Manaf, N.S.A.; Kudin, T.I.T.; Yahya, M.Z.A.

2015-01-01

Highlights: • Activated carbon and single-walled CNT based electrochemical capacitor. • Electrochemical analysis by means of CV, charge/discharge and impedance. • 1 M LiPF 6 non-aqueous solution as an electrolyte. • AC/SWCNT electrode exhibits a maximum capacitance of 60.97 F g −1 . - Abstract: Carbon nanotubes have been extensively studied because of their wide range of potential application such as in nanoscale electric circuits, textiles, transportation, health, and the environment. Carbon nanotubes feature extraordinary properties, such as electrical conductivities higher than those of copper, hardness and thermal conductivity higher than those of diamond, and strength surpassing that of steel, among others. This research focuses on the fabrication of an energy storage device, namely, an electrochemical capacitor, by using carbon materials, i.e., activated carbon and single-walled carbon nanotubes, of a specific weight ratio as electrode materials. The electrolyte functioning as an ion carrier is 1 M lithium hexafluorophosphate. Variations in the electrochemical performance of the device, including its capacitance, charge/discharge characteristics, and impedance, are reported in this paper. The electrode proposed in this work exhibits a maximum capacitance of 60.97 F g −1 at a scan rate of 1 mV s −1

Multifunctional Electroactive Nanocomposites Based on Piezoelectric Boron Nitride Nanotubes

Science.gov (United States)

Kang, Jin Ho; Sauti, Godfrey; Park, Cheol; Yamakov, Vesselin I.; Wise, Kristopher E.; Lowther, Sharon E.; Fay, Catharine C.; Thibeault, Sheila A.; Bryant, Robert G.

2015-01-01

Space exploration missions require sensors and devices capable of stable operation in harsh environments such as those that include high thermal fluctuation, atomic oxygen, and high-energy ionizing radiation. However, conventional or state-of-the-art electroactive materials like lead zirconate titanate, poly(vinylidene fluoride), and carbon nanotube (CNT)-doped polyimides have limitations on use in those extreme applications. Theoretical studies have shown that boron nitride nanotubes (BNNTs) have strength-to-weight ratios comparable to those of CNTs, excellent high-temperature stability (to 800 C in air), large electroactive characteristics, and excellent neutron radiation shielding capability. In this study, we demonstrated the experimental electroactive characteristics of BNNTs in novel multifunctional electroactive nanocomposites. Upon application of an external electric field, the 2 wt % BNNT/polyimide composite was found to exhibit electroactive strain composed of a superposition of linear piezoelectric and nonlinear electrostrictive components. When the BNNTs were aligned by stretching the 2 wt % BNNT/polyimide composite, electroactive characteristics increased by about 460% compared to the nonstretched sample. An all-nanotube actuator consisting of a BNNT buckypaper layer between two single-walled carbon nanotube buck-paper electrode layers was found to have much larger electroactive properties. The additional neutron radiation shielding properties and ultraviolet/visible/near-infrared optical properties of the BNNT composites make them excellent candidates for use in the extreme environments of space missions. utilizing the unique characteristics of BNNTs.

Carbon nanotube network-silicon oxide non-volatile switches.

Science.gov (United States)

Liao, Albert D; Araujo, Paulo T; Xu, Runjie; Dresselhaus, Mildred S

2014-12-08

The integration of carbon nanotubes with silicon is important for their incorporation into next-generation nano-electronics. Here we demonstrate a non-volatile switch that utilizes carbon nanotube networks to electrically contact a conductive nanocrystal silicon filament in silicon dioxide. We form this device by biasing a nanotube network until it physically breaks in vacuum, creating the conductive silicon filament connected across a small nano-gap. From Raman spectroscopy, we observe coalescence of nanotubes during breakdown, which stabilizes the system to form very small gaps in the network~15 nm. We report that carbon nanotubes themselves are involved in switching the device to a high resistive state. Calculations reveal that this switching event occurs at ~600 °C, the temperature associated with the oxidation of nanotubes. Therefore, we propose that, in switching to a resistive state, the nanotube oxidizes by extracting oxygen from the substrate.

TiO2 Nanotubes: Recent Advances in Synthesis and Gas Sensing Properties

Directory of Open Access Journals (Sweden)

Giorgio Sberveglieri

2013-10-01

Full Text Available Synthesis—particularly by electrochemical anodization-, growth mechanism and chemical sensing properties of pure, doped and mixed titania tubular arrays are reviewed. The first part deals on how anodization parameters affect the size, shape and morphology of titania nanotubes. In the second part fabrication of sensing devices based on titania nanotubes is presented, together with their most notable gas sensing performances. Doping largely improves conductivity and enhances gas sensing performances of TiO2 nanotubes

Electronic Transport Parameter of Carbon Nanotube Metal-Semiconductor On-Tube Heterojunction

Directory of Open Access Journals (Sweden)

Sukirno

2009-03-01

Full Text Available Carbon Nanotubes research is one of the top five hot research topics in physics since 2006 because of its unique properties and functionalities, which leads to wide-range applications. One of the most interesting potential applications is in term of nanoelectronic device. It has been modeled carbon nanotubes heterojunction, which was built from two different carbon nanotubes, that one is metallic and the other one is semiconducting. There are two different carbon nanotubes metal-semiconductor heterojunction. The first one is built from CNT(10,10 as metallic carbon nanotube and CNT (17,0 as semiconductor carbon nanotube. The other one is built from CNT (5,5 as metallic carbon nanotube and CNT (8,0. All of the semiconducting carbon nanotubes are assumed to be a pyridine-like N-doped. Those two heterojunctions are different in term of their structural shape and diameter. It has been calculated their charge distribution and potential profile, which would be useful for the simulation of their electronic transport properties. The calculations are performed by using self-consistent method to solve Non-Homogeneous Poisson’s Equation with aid of Universal Density of States calculation method for Carbon Nanotubes. The calculations are done by varying the doping fraction of the semiconductor carbon nanotubes The electron tunneling transmission coefficient, for low energy region, also has been calculated by using Wentzel-Kramer-Brillouin (WKB approximation. From the calculation results, it is obtained that the charge distribution as well as the potential profile of this device is doping fraction dependent. It is also inferred that the WKB method is fail to be used to calculate whole of the electron tunneling coefficient in this system. It is expected that further calculation for electron tunneling coefficient in higher energy region as well as current-voltage characteristic of this system will become an interesting issue for this carbon nanotube based

Fabrication of self-enclosed nanochannels based on capillary-pressure balance mechanism

Science.gov (United States)

Kou, Yu; Sang, Aixia; Li, Xin; Wang, Xudi

2017-10-01

Polymer-based micro/nano fluidic devices are becoming increasingly important to biological applications and fluidic control. In this paper, we propose a self-enclosure method for the fabrication of large-area nanochannels without external force by using a capillary-pressure balance mechanism. The melt polymer coated on the nanogrooves fills into the trenches inevitably and the air in the trenches is not excluded but compressed, which leads to an equilibrium state between pressure of the trapped air and capillary force of melt polymer eventually, resulting in the channels’ formation. A pressure balance model was proposed to elucidate the unique self-sealing phenomenon and the criteria for the design and construction of sealed channels was discussed. According to the bonding mechanism investigated using the volume of fluid (VOF) simulation and experiments, we can control the dimension of sealed channels by varying the baking condition. This fabrication technique has great potential for low-cost and mass production of polymeric-based micro/nano fluidic devices.

Roll-to-Roll production of carbon nanotubes based supercapacitors

Science.gov (United States)

Zhu, Jingyi; Childress, Anthony; Karakaya, Mehmet; Roberts, Mark; Arcilla-Velez, Margarita; Podila, Ramakrishna; Rao, Apparao

2014-03-01

Carbon nanomaterials provide an excellent platform for electrochemical double layer capacitors (EDLCs). However, current industrial methods for producing carbon nanotubes are expensive and thereby increase the costs of energy storage to more than 10 Wh/kg. In this regard, we developed a facile roll-to-roll production technology for scalable manufacturing of multi-walled carbon nanotubes (MWNTs) with variable density on run-of-the-mill kitchen Al foils. Our method produces MWNTs with diameter (heights) between 50-100 nm (10-100 μm), and a specific capacitance as high as ~ 100 F/g in non-aqueous electrolytes. In this talk, the fundamental challenges involved in EDLC-suitable MWNT growth, roll-to-roll production, and device manufacturing will be discussed along with electrochemical characteristics of roll-to-roll MWNTs. Research supported by NSF CMMI Grant1246800.

Development of a continuous-flow fluidic pump

International Nuclear Information System (INIS)

Robinson, S.M.

1985-08-01

A study was made of a fluidic pump which utilizes gas pistons, a venturi-like reverse-flow-diverter, and a planar Y-type flow junction to produce a continuous flow of liquid from a system containing no moving parts. The study included an evaluation of the system performance and of methods for controlling the stability of the fluidic system. A mathematical model of the system was developed for steady-state operation using accepted theories of fluid mechanics. Although more elaborate models are needed for detailed design and optimization of specific systems, the model determined some of the main factors controlling the system performance and will be used in the development of more accurate models. 49 refs., 39 figs., 9 tabs

Functionalization of vertically aligned carbon nanotubes

Directory of Open Access Journals (Sweden)

Eloise Van Hooijdonk

2013-02-01

Full Text Available This review focuses and summarizes recent studies on the functionalization of carbon nanotubes oriented perpendicularly to their substrate, so-called vertically aligned carbon nanotubes (VA-CNTs. The intrinsic properties of individual nanotubes make the VA-CNTs ideal candidates for integration in a wide range of devices, and many potential applications have been envisaged. These applications can benefit from the unidirectional alignment of the nanotubes, the large surface area, the high carbon purity, the outstanding electrical conductivity, and the uniformly long length. However, practical uses of VA-CNTs are limited by their surface characteristics, which must be often modified in order to meet the specificity of each particular application. The proposed approaches are based on the chemical modifications of the surface by functionalization (grafting of functional chemical groups, decoration with metal particles or wrapping of polymers to bring new properties or to improve the interactions between the VA-CNTs and their environment while maintaining the alignment of CNTs.

Functionalization of vertically aligned carbon nanotubes.

Science.gov (United States)

Van Hooijdonk, Eloise; Bittencourt, Carla; Snyders, Rony; Colomer, Jean-François

2013-01-01

This review focuses and summarizes recent studies on the functionalization of carbon nanotubes oriented perpendicularly to their substrate, so-called vertically aligned carbon nanotubes (VA-CNTs). The intrinsic properties of individual nanotubes make the VA-CNTs ideal candidates for integration in a wide range of devices, and many potential applications have been envisaged. These applications can benefit from the unidirectional alignment of the nanotubes, the large surface area, the high carbon purity, the outstanding electrical conductivity, and the uniformly long length. However, practical uses of VA-CNTs are limited by their surface characteristics, which must be often modified in order to meet the specificity of each particular application. The proposed approaches are based on the chemical modifications of the surface by functionalization (grafting of functional chemical groups, decoration with metal particles or wrapping of polymers) to bring new properties or to improve the interactions between the VA-CNTs and their environment while maintaining the alignment of CNTs.

Electronics with carbon nanotubes

International Nuclear Information System (INIS)

Avouris, P.

2007-01-01

From mobile phones and laptops to Xboxes and iPods, it is difficult to think of any aspect of modern life that has not been touched by developments in electronics, computing and communications over the last few decades. Many of these technological advances have arisen from our ability to create ever smaller electronic devices, in particular silicon-based field effect transistors (FETs), which has led to denser, faster and less power-hungry circuits. The problem is that this device miniaturization, or 'scaling', cannot continue forever. Fundamental scientific and technological limitations exist that will make it impossible to build better performing silicon devices below a certain size. This potential show-stopper has inspired a worldwide effort to develop alternative device technologies based on 1D materials or those that exploit the spin, as well as the charge, of electrons. One promising and, in principle, simpler approach is to maintain the operating concept of today's silicon-based FETs but to replace a key component of the device - the semiconducting silicon channel - with 1D nanostructures that have much more versatile electrical-transport properties. Among the different 1D materials that have been developed, those with the most desirable properties are 'single-walled' carbon nanotubes, which were first created in 1993 by Sumio Ijima at the NEC Fundamental Research Laboratory in Tsukuba, Japan, and by Donald Bethune of IBM's Almaden Research Center in California. These materials are hollow tubes made from rolled up sheets of carbon just one atom thick, otherwise known as graphene. In the March issue of Physics World, Phaedon Avouris discusses some of the many properties and applications of carbon nanotubes, which he describes as an 'engineer's dream' because of their exceptionally high strength and heat conduction. (U.K.)

Optimizing the e-beam profile of a single carbon nanotube field emission device for electric propulsion systems

Directory of Open Access Journals (Sweden)

Juliano Fujioka Mologni

2010-04-01

Full Text Available Preliminary studies on field emission (FE arrays comprised of carbon nanotubes (CNT as an electron source for electric propulsion system show remarkably promising results. Design parameters for a carbon nanotube (CNT field-emission device operating on triode configuration were numerically simulated and optimized in order to enhance the e-beam focusing quality. An additional focus gate (FG was integrated to the device to control the profile of the emitted e-beam. An axisymmetric finite element model was developed to calculate the electric field distribution on the vacuum region and a modified Fowler-Nordheim (FN equation was used to evaluate the current density emission and the effective emitter area. Afterward, a FE simulation was employed in order to calculate the trajectory of the emitted electrons and define the electron-optical properties of the e-beam. The integration of the FG was fully investigated via computational intelligence techniques. The best performance device according to our simulations presents a collimated e-beam profile that suits well for field emission displays, magnetic field detection and electron microscopy. The automated computational design tool presented in this study strongly benefits the robust design of integrated electron-optical systems for vacuum field emission applications, including electrodynamic tethering and electric propulsion systems.

High frequency electromechanical memory cells based on telescoping carbon nanotubes.

Science.gov (United States)

Popov, A M; Lozovik, Y E; Kulish, A S; Bichoutskaia, E

2010-07-01

A new method to increase the operational frequency of electromechanical memory cells based on the telescoping motion of multi-walled carbon nanotubes through the selection of the form of the switching voltage pulse is proposed. The relative motion of the walls of carbon nanotubes can be controlled through the shape of the interwall interaction energy surface. This allows the use of the memory cells in nonvolatile or volatile regime, depending on the structure of carbon nanotube. Simulations based on ab initio and semi-empirical calculations of the interwall interaction energies are used to estimate the switching voltage and the operational frequency of volatile cells with the electrodes made of carbon nanotubes. The lifetime of nonvolatile memory cells is also predicted.

A vertically aligned carbon nanotube-based impedance sensing biosensor for rapid and high sensitive detection of cancer cells.

Science.gov (United States)

Abdolahad, Mohammad; Taghinejad, Mohammad; Taghinejad, Hossein; Janmaleki, Mohsen; Mohajerzadeh, Shams

2012-03-21

A novel vertically aligned carbon nanotube based electrical cell impedance sensing biosensor (CNT-ECIS) was demonstrated for the first time as a more rapid, sensitive and specific device for the detection of cancer cells. This biosensor is based on the fast entrapment of cancer cells on vertically aligned carbon nanotube arrays and leads to mechanical and electrical interactions between CNT tips and entrapped cell membranes, changing the impedance of the biosensor. CNT-ECIS was fabricated through a photolithography process on Ni/SiO(2)/Si layers. Carbon nanotube arrays have been grown on 9 nm thick patterned Ni microelectrodes by DC-PECVD. SW48 colon cancer cells were passed over the surface of CNT covered electrodes to be specifically entrapped on elastic nanotube beams. CNT arrays act as both adhesive and conductive agents and impedance changes occurred as fast as 30 s (for whole entrapment and signaling processes). CNT-ECIS detected the cancer cells with the concentration as low as 4000 cells cm(-2) on its surface and a sensitivity of 1.7 × 10(-3)Ω cm(2). Time and cell efficiency factor (TEF and CEF) parameters were defined which describe the sensor's rapidness and resolution, respectively. TEF and CEF of CNT-ECIS were much higher than other cell based electrical biosensors which are compared in this paper.

Metal contact engineering and registration-free fabrication of complementary metal-oxide semiconductor integrated circuits using aligned carbon nanotubes.

Science.gov (United States)

Wang, Chuan; Ryu, Koungmin; Badmaev, Alexander; Zhang, Jialu; Zhou, Chongwu

2011-02-22

Complementary metal-oxide semiconductor (CMOS) operation is very desirable for logic circuit applications as it offers rail-to-rail swing, larger noise margin, and small static power consumption. However, it remains to be a challenging task for nanotube-based devices. Here in this paper, we report our progress on metal contact engineering for n-type nanotube transistors and CMOS integrated circuits using aligned carbon nanotubes. By using Pd as source/drain contacts for p-type transistors, small work function metal Gd as source/drain contacts for n-type transistors, and evaporated SiO(2) as a passivation layer, we have achieved n-type transistor, PN diode, and integrated CMOS inverter with an air-stable operation. Compared with other nanotube n-doping techniques, such as potassium doping, PEI doping, hydrazine doping, etc., using low work function metal contacts for n-type nanotube devices is not only air stable but also integrated circuit fabrication compatible. Moreover, our aligned nanotube platform for CMOS integrated circuits shows significant advantage over the previously reported individual nanotube platforms with respect to scalability and reproducibility and suggests a practical and realistic approach for nanotube-based CMOS integrated circuit applications.

Carbon nanotubes in neuroregeneration and repair.

Science.gov (United States)

Fabbro, Alessandra; Prato, Maurizio; Ballerini, Laura

2013-12-01

In the last decade, we have experienced an increasing interest and an improved understanding of the application of nanotechnology to the nervous system. The aim of such studies is that of developing future strategies for tissue repair to promote functional recovery after brain damage. In this framework, carbon nanotube based technologies are emerging as particularly innovative tools due to the outstanding physical properties of these nanomaterials together with their recently documented ability to interface neuronal circuits, synapses and membranes. This review will discuss the state of the art in carbon nanotube technology applied to the development of devices able to drive nerve tissue repair; we will highlight the most exciting findings addressing the impact of carbon nanotubes in nerve tissue engineering, focusing in particular on neuronal differentiation, growth and network reconstruction. © 2013.

High-frequency fluidic oscillator

Czech Academy of Sciences Publication Activity Database

Tesař, Václav

2015-01-01

Roč. 234, October (2015), s. 158-167 ISSN 0924-4247 R&D Projects: GA ČR GA13-23046S Institutional support: RVO:61388998 Keywords : pulsating flow * jet * fluidics Subject RIV: BK - Fluid Dynamics Impact factor: 2.201, year: 2015 http://www.sciencedirect.com/science/article/pii/S0924424715301114/pdfft?md5=42ec4f6f3180151913ceade1e4625d74&pid=1-s2.0-S0924424715301114-main.pdf

On the elastic properties of carbon nanotube-based composites: modelling and characterization

CERN Document Server

Thostenson, E T

2003-01-01

The exceptional mechanical and physical properties observed for carbon nanotubes has stimulated the development of nanotube-based composite materials, but critical challenges exist before we can exploit these extraordinary nanoscale properties in a macroscopic composite. At the nanoscale, the structure of the carbon nanotube strongly influences the overall properties of the composite. The focus of this research is to develop a fundamental understanding of the structure/size influence of carbon nanotubes on the elastic properties of nanotube-based composites. Towards this end, the nanoscale structure and elastic properties of a model composite system of aligned multi-walled carbon nanotubes embedded in a polystyrene matrix were characterized, and a micromechanical approach for modelling of short fibre composites was modified to account for the structure of the nanotube reinforcement to predict the elastic modulus of the nanocomposite as a function of the constituent properties, reinforcement geometry and nanot...

Carbon Nanotube Based Molecular Electronics and Motors: A View from Classical and Quantum Dynamics Simulations

Science.gov (United States)

Srivastava, Deepak; Saini, Subhash (Technical Monitor)

1998-01-01

The tubular forms of fullerenes popularly known as carbon nanotubes are experimentally produced as single-, multiwall, and rope configurations. The nanotubes and nanoropes have shown to exhibit unusual mechanical and electronic properties. The single wall nanotubes exhibit both semiconducting and metallic behavior. In short undefected lengths they are the known strongest fibers which are unbreakable even when bent in half. Grown in ropes their tensile strength is approximately 100 times greater than steel at only one sixth the weight. Employing large scale classical and quantum molecular dynamics simulations we will explore the use of carbon nanotubes and carbon nanotube junctions in 2-, 3-, and 4-point molecular electronic device components, dynamic strength characterization for compressive, bending and torsional strains, and chemical functionalization for possible use in a nanoscale molecular motor. The above is an unclassified material produced for non-competitive basic research in the nanotechnology area.

Ab initio assisted process modeling for Si-based nanoelectronic devices

International Nuclear Information System (INIS)

Windl, Wolfgang

2005-01-01

In this paper, we discuss concepts and examples of ab initio calculations assisting physics-based process simulation. We focus on how to determine diffusion and reaction constants, where modern methods such as the nudged elastic band method allow a systematic and reliable search for the minimum energy migration path and barrier. We show that once the saddle point is determined, the underlying harmonic transition state theory also allows to calculate the prefactors. The discussed examples include nitrogen diffusion, boron deactivation and boron interface segregation. Finally, some concepts are discussed for future device technologies such as molecular devices, where the currently prevalent multiscale approach (kinetic parameters used in higher level models like diffusion-reaction or kinetic Monte Carlo modeling) would not be sensible anymore. As an example, we described the ab initio temperature-accelerated dynamics modeling of contact formation in carbon nanotube devices

A novel polymer nanotube composite for photovoltaic packaging applications

International Nuclear Information System (INIS)

Ravichandran, J; Manna, I; Manoj, A G; Liu, J; Carroll, D L

2008-01-01

Packaging of organic photovoltaic (OPV) devices is an important issue which has been rarely addressed in the past. With the recent reports of high efficiency organic photovoltaics (6%), the need to produce materials which can effectively protect the device from degradation due to exposure to oxygen, moisture and radiation is pressing. We report a novel Saran (a co-polymer of vinylidene chloride and acrylonitrile) based polymer nanotube composite, which shows high transparency in the visible region, good barrier properties and thermal stability, for use as an encapsulant for OPV devices. Different loadings of Saran and boron nitride nanotubes were taken and the composites were prepared to optimize the composition of the composite. UV-visible spectroscopy, infra-red spectroscopy and thermal analysis were used to characterize the composite. The barrier properties of the composite were tested on poly(3-hexylthiophene), which is used in high efficiency OPV devices

Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes.

Science.gov (United States)

Lipomi, Darren J; Vosgueritchian, Michael; Tee, Benjamin C-K; Hellstrom, Sondra L; Lee, Jennifer A; Fox, Courtney H; Bao, Zhenan

2011-10-23

Transparent, elastic conductors are essential components of electronic and optoelectronic devices that facilitate human interaction and biofeedback, such as interactive electronics, implantable medical devices and robotic systems with human-like sensing capabilities. The availability of conducting thin films with these properties could lead to the development of skin-like sensors that stretch reversibly, sense pressure (not just touch), bend into hairpin turns, integrate with collapsible, stretchable and mechanically robust displays and solar cells, and also wrap around non-planar and biological surfaces such as skin and organs, without wrinkling. We report transparent, conducting spray-deposited films of single-walled carbon nanotubes that can be rendered stretchable by applying strain along each axis, and then releasing this strain. This process produces spring-like structures in the nanotubes that accommodate strains of up to 150% and demonstrate conductivities as high as 2,200 S cm(-1) in the stretched state. We also use the nanotube films as electrodes in arrays of transparent, stretchable capacitors, which behave as pressure and strain sensors.

Femtosecond laser ablation of single-wall carbon nanotube-based material

International Nuclear Information System (INIS)

Danilov, Pavel A; Ionin, Andrey A; Kudryashov, Sergey I; Makarov, Sergey V; Mel’nik, Nikolay N; Rudenko, Andrey A; Yurovskikh, Vladislav I; Zayarny, Dmitry V; Lednev, Vasily N; Obraztsova, Elena D; Pershin, Sergey M; Bunkin, Alexey F

2014-01-01

Single- and multi-shot femtosecond laser surface ablation of a single-wall carbon nanotube-based substrate at 515- and 1030 nm wavelengths was studied by scanning electron microscopy and micro-Raman spectroscopy. The laser ablation proceeds in two ways: as the low-fluence mesoscopic shallow disintegration of the surface nanotube packing, preserving the individual integrity and the semiconducting character of the nanotubes or as the high-fluence deep material removal apparently triggered by the strong intrinsic or impurity-mediated ablation of the individual carbon nanotubes on the substrate surface. (letter)

Carbon Nanotube Based Chemical Sensors for Space and Terrestrial Applications

Science.gov (United States)

Li, Jing; Lu, Yijiang

2009-01-01

A nanosensor technology has been developed using nanostructures, such as single walled carbon nanotubes (SWNTs), on a pair of interdigitated electrodes (IDE) processed with a silicon-based microfabrication and micromachining technique. The IDE fingers were fabricated using photolithography and thin film metallization techniques. Both in-situ growth of nanostructure materials and casting of the nanostructure dispersions were used to make chemical sensing devices. These sensors have been exposed to nitrogen dioxide, acetone, benzene, nitrotoluene, chlorine, and ammonia in the concentration range of ppm to ppb at room temperature. The electronic molecular sensing of carbon nanotubes in our sensor platform can be understood by intra- and inter-tube electron modulation in terms of charge transfer mechanisms. As a result of the charge transfer, the conductance of p-type or hole-richer SWNTs in air will change. Due to the large surface area, low surface energy barrier and high thermal and mechanical stability, nanostructured chemical sensors potentially can offer higher sensitivity, lower power consumption and better robustness than the state-of-the-art systems, which make them more attractive for defense and space applications. Combined with MEMS technology, light weight and compact size sensors can be made in wafer scale with low cost. Additionally, a wireless capability of such a sensor chip can be used for networked mobile and fixed-site detection and warning systems for military bases, facilities and battlefield areas.

Activated carbon and single-walled carbon nanotube based electrochemical capacitor in 1 M LiPF{sub 6} electrolyte

Energy Technology Data Exchange (ETDEWEB)

Azam, M.A., E-mail: asyadi@utem.edu.my [Carbon Research Technology Research Group, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia); Jantan, N.H.; Dorah, N.; Seman, R.N.A.R.; Manaf, N.S.A. [Carbon Research Technology Research Group, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100 Durian Tunggal, Melaka (Malaysia); Kudin, T.I.T. [Ionics Materials & Devices Research Laboratory, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor (Malaysia); Yahya, M.Z.A. [Ionics Materials & Devices Research Laboratory, Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor (Malaysia); National Defence University of Malaysia, Kem Sungai Besi, 57000 Kuala Lumpur (Malaysia)

2015-09-15

Highlights: • Activated carbon and single-walled CNT based electrochemical capacitor. • Electrochemical analysis by means of CV, charge/discharge and impedance. • 1 M LiPF{sub 6} non-aqueous solution as an electrolyte. • AC/SWCNT electrode exhibits a maximum capacitance of 60.97 F g{sup −1}. - Abstract: Carbon nanotubes have been extensively studied because of their wide range of potential application such as in nanoscale electric circuits, textiles, transportation, health, and the environment. Carbon nanotubes feature extraordinary properties, such as electrical conductivities higher than those of copper, hardness and thermal conductivity higher than those of diamond, and strength surpassing that of steel, among others. This research focuses on the fabrication of an energy storage device, namely, an electrochemical capacitor, by using carbon materials, i.e., activated carbon and single-walled carbon nanotubes, of a specific weight ratio as electrode materials. The electrolyte functioning as an ion carrier is 1 M lithium hexafluorophosphate. Variations in the electrochemical performance of the device, including its capacitance, charge/discharge characteristics, and impedance, are reported in this paper. The electrode proposed in this work exhibits a maximum capacitance of 60.97 F g{sup −1} at a scan rate of 1 mV s{sup −1}.

Reagentless D-sorbitol biosensor based on D-sorbitol dehydrogenase immobilized in a sol-gel carbon nanotubes-poly(methylene green) composite.

Science.gov (United States)

Wang, Zhijie; Etienne, Mathieu; Urbanova, Veronika; Kohring, Gert-Wieland; Walcarius, Alain

2013-04-01

A reagentless D-sorbitol biosensor based on NAD-dependent D-sorbitol dehydrogenase (DSDH) immobilized in a sol-gel carbon nanotubes-poly(methylene green) composite has been developed. It was prepared by durably immobilizing the NAD(+) cofactor with DSDH in a sol-gel thin film on the surface of carbon nanotubes functionalized with poly(methylene green). This device enables selective determination of D-sorbitol at 0.2 V with a sensitivity of 8.7 μA mmol(-1) L cm(-2) and a detection limit of 0.11 mmol L(-1). Moreover, this biosensor has excellent operational stability upon continuous use in hydrodynamic conditions.

Vibration analysis of carbon nanotubes-based zeptogram masses sensors and taking into account their rotatory inertia

Directory of Open Access Journals (Sweden)

Azrar A.

2018-01-01

Full Text Available In this research work, the transverse vibration behaviour of single-walled carbon nanotubes (SCNT based mass sensors is studied using the Timoshenko beam and nonlocal elasticity theories. The nonlocal constitutive equations are used in the formulations and the CNT with different lengths, attached mass (viruses and bacteria and the general boundary conditions are considered. The dimensionless frequencies and associated modes are obtained for one and two attached masses and different boundary conditions. The effects of transverse shear deformation and rotatory inertia, nonlocal parameter, length of the carbon nanotubes, and attached mass and its location are investigated in detail for each considered problem. The relationship between the frequencies and mode shapes of the sensor and the attached zeptogramme masses are obtained. The sensing devices for biological objects including viruses and bacteria can be elaborated based on the developed sensitivity and frequency shift methodological approach.

Doped Halloysite Nanotubes for Use in the 3D Printing of Medical Devices

Directory of Open Access Journals (Sweden)

Jeffery A. Weisman

2017-12-01

Full Text Available Previous studies have established halloysite nanotubes (HNTs as viable nanocontainers capable of sustained release of a variety of antibiotics, corrosion agents, chemotherapeutics and growth factors either from their lumen or in outer surface coatings. Accordingly, halloysite nanotubes (HNTs hold great promise as drug delivery carriers in the fields of pharmaceutical science and regenerative medicine. This study explored the potential of 3D printing drug doped HNT constructs. We used a model drug, gentamicin (GS and polylactic acid (PLA to fabricate GS releasing disks, beads, and pellets. Gentamicin was released from 3D printed constructs in a sustained manner and had a superior anti-bacterial growth inhibition effect that was dependent on GS doping concentration. While this study focused on a model drug, gentamicin, combination therapy is possible through the fabrication of medical devices containing HNTs doped with a suite of antibiotics or antifungals. Furthermore, tailored dosage levels, suites of antimicrobials, delivered locally would reduce the toxicity of individual agents, prevent the emergence of resistant strains, and enable the treatment of mixed infections.

A micro-fluidic study of whole blood behaviour on PMMA topographical nanostructures

Directory of Open Access Journals (Sweden)

Tsud Nataliya

2008-02-01

Full Text Available Abstract Background Polymers are attractive materials for both biomedical engineering and cardiovascular applications. Although nano-topography has been found to influence cell behaviour, no established method exists to understand and evaluate the effects of nano-topography on polymer-blood interaction. Results We optimized a micro-fluidic set-up to study the interaction of whole blood with nano-structured polymer surfaces under flow conditions. Micro-fluidic chips were coated with polymethylmethacrylate films and structured by polymer demixing. Surface feature size varied from 40 nm to 400 nm and feature height from 5 nm to 50 nm. Whole blood flow rate through the micro-fluidic channels, platelet adhesion and von Willebrand factor and fibrinogen adsorption onto the structured polymer films were investigated. Whole blood flow rate through the micro-fluidic channels was found to decrease with increasing average surface feature size. Adhesion and spreading of platelets from whole blood and von Willebrand factor adsorption from platelet poor plasma were enhanced on the structured surfaces with larger feature, while fibrinogen adsorption followed the opposite trend. Conclusion We investigated whole blood behaviour and plasma protein adsorption on nano-structured polymer materials under flow conditions using a micro-fluidic set-up. We speculate that surface nano-topography of polymer films influences primarily plasma protein adsorption, which results in the control of platelet adhesion and thrombus formation.

Refractive index sensor based on total scattering of plasmonic nanotube

Science.gov (United States)

Yao, Kaiqiang; Zeng, Qingbing; Hu, Zengrong; Zhan, Yaohui

2018-03-01

Plasmonic nanostructures can couple free space light into anultrafine space; therefore,they are employed extensively in the refractive index sensors to minimize the device size or further improve the detection sensitivity. In this work, the optical response of the plasmonic nanotube are investigated comprehensively by using full wave finite element method. With a subwavelength scale, the silver nanotube have prominent scattering peaks in the visible range, which is very suitable for observing through the dark field microscope. The geometric dependence of the scattering spectra and the sensing performance are evaluated carefully. Results show that the scattering peaks are in linear relationship to the circumstance refractive index and a sensitivity of 337 nm/RIUcan be achieved easily by such a plasmonicnanotube with an optimized size.

LDRD final report : energy conversion using chromophore-functionalized carbon nanotubes.

Energy Technology Data Exchange (ETDEWEB)

Vance, Andrew L.; Zifer, Thomas; Zhou, Xinjian; Leonard, Francois Leonard; Wong, Bryan Matthew; Kane, Alexander; Katzenmeyer, Aaron Michael; Krafcik, Karen Lee

2010-09-01

With the goal of studying the conversion of optical energy to electrical energy at the nanoscale, we developed and tested devices based on single-walled carbon nanotubes functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific absorption windows in the visible spectrum and anchoring them to the nanotube surface, we demonstrated the controlled detection of visible light of low intensity in narrow ranges of wavelengths. Our measurements suggested that upon photoabsorption, the chromophores isomerize to give a large change in dipole moment, changing the electrostatic environment of the nanotube. All-electron ab initio calculations were used to study the chromophore-nanotube hybrids, and show that the chromophores bind strongly to the nanotubes without disturbing the electronic structure of either species. Calculated values of the dipole moments supported the notion of dipole changes as the optical detection mechanism.

Enhanced performance of light-emitting diodes based on a nanocomposite of dehydrated nanotube titanic acid and poly(vinylcarbazole) (PVK)

Energy Technology Data Exchange (ETDEWEB)

Qian, L. [Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China)]. E-mail: qian_lei@126.com; Yang, S.Y. [Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China); Jin, Z.S. [Key Laboratory on Special Functional Materials, Henan University, Kaifeng 475001 (China); Zhang, Z.J. [Key Laboratory on Special Functional Materials, Henan University, Kaifeng 475001 (China); Zhang, T. [Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China); Teng, F. [Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China); Xu, X.R. [Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China)

2005-01-31

Performance of light-emitting diodes (LEDs) based on a nanocomposite of dehydrated nanotube titanic acid (DNTA) and poly(vinylcarbazole) (PVK) as emissive layer, i.e., ITO/PVK:DNTA(2 wt%)(100 nm)/BCP(30 nm)/Alq{sub 3}(10 nm)/LiF(1 nm)/Al [device D{sub 2}], was reported. By investigation of the luminance and electric characteristics of the device, we found that the performance of device D{sub 2} was greatly improved. The recombination zone changed evidently due to the improvement of holes mobility. Compared with those devices without incorporating DNTA, both the maximum luminance and the electroluminescent efficiency of the device D{sub 2} can be improved by a factor of three. Furthermore, the turn-on voltage of the device decreased dramatically.

High-Performance Ttransparent and Stretchable All-Solid Supercapacitors Based on Highly Aligned Carbon Nanotube Sheets

Science.gov (United States)

2014-01-09

supercapacitors based on poly ( ionic liquid )- modified graphene electrodes. ACS Nano 5, 436–442 (2011). 34. Denisa, H.-J. et al. Highly stable performance of...Niu, Z. et al. A repeated halving approach to fabricate ultrathin single-walled carbon nanotube films for transparent supercapacitors. Small 9, 518–524...PVA-H3PO4/CNT/PDMS multilayer film in either a parallel (Figure 1b) or cross (Figure 1c) configuration, leading to highly transparent devices to be

Design, Fabrication, and Characterization of Carbon Nanotube Field Emission Devices for Advanced Applications

Science.gov (United States)

Radauscher, Erich Justin

Carbon nanotubes (CNTs) have recently emerged as promising candidates for electron field emission (FE) cathodes in integrated FE devices. These nanostructured carbon materials possess exceptional properties and their synthesis can be thoroughly controlled. Their integration into advanced electronic devices, including not only FE cathodes, but sensors, energy storage devices, and circuit components, has seen rapid growth in recent years. The results of the studies presented here demonstrate that the CNT field emitter is an excellent candidate for next generation vacuum microelectronics and related electron emission devices in several advanced applications. The work presented in this study addresses determining factors that currently confine the performance and application of CNT-FE devices. Characterization studies and improvements to the FE properties of CNTs, along with Micro-Electro-Mechanical Systems (MEMS) design and fabrication, were utilized in achieving these goals. Important performance limiting parameters, including emitter lifetime and failure from poor substrate adhesion, are examined. The compatibility and integration of CNT emitters with the governing MEMS substrate (i.e., polycrystalline silicon), and its impact on these performance limiting parameters, are reported. CNT growth mechanisms and kinetics were investigated and compared to silicon (100) to improve the design of CNT emitter integrated MEMS based electronic devices, specifically in vacuum microelectronic device (VMD) applications. Improved growth allowed for design and development of novel cold-cathode FE devices utilizing CNT field emitters. A chemical ionization (CI) source based on a CNT-FE electron source was developed and evaluated in a commercial desktop mass spectrometer for explosives trace detection. This work demonstrated the first reported use of a CNT-based ion source capable of collecting CI mass spectra. The CNT-FE source demonstrated low power requirements, pulsing

Self-grafting carbon nanotubes on polymers for stretchable electronics

Science.gov (United States)

Morales, Piero; Moyanova, Slavianka; Pavone, Luigi; Fazi, Laura; Mirabile Gattia, Daniele; Rapone, Bruno; Gaglione, Anderson; Senesi, Roberto

2018-06-01

Elementary bidimensional circuitry made of single-wall carbon-nanotube-based conductors, self-grafted on different polymer films, is accomplished in an attempt to develop a simple technology for flexible and stretchable electronic devices. Unlike in other studies of polymer-carbon nanotube composites, no chemical functionalization of single-wall carbon nanotubes is necessary for stable grafting onto several polymeric surfaces, suggesting viable and cheap fabrication technologies for stretchable microdevices. Electrical characterization of both unstretched and strongly stretched conductors is provided, while an insight on the mechanisms of strong adhesion to the polymer is obtained by scanning electron microscopy of the surface composite. As a first example of technological application, the electrical functionality of a carbon-nanotube-based 6-sensor (electrode) grid was demonstrated by recording of subdural electrocorticograms in freely moving rats over approximately three months. The results are very promising and may serve as a basis for future work targeting clinical applications.

Carbon Nanotube Bolometer for Absolute FTIR Spectroscopy

Science.gov (United States)

Woods, Solomon; Neira, Jorge; Tomlin, Nathan; Lehman, John

We have developed and calibrated planar electrical-substitution bolometers which employ absorbers made from vertically-aligned carbon nanotube arrays. The nearly complete absorption of light by the carbon nanotubes from the visible range to the far-infrared can be exploited to enable a device with read-out in native units equivalent to optical power. Operated at cryogenic temperatures near 4 K, these infrared detectors are designed to have time constant near 10 ms and a noise floor of about 10 pW. Built upon a micro-machined silicon platform, each device has an integrated heater and thermometer, either a carbon nanotube thermistor or superconducting transition edge sensor, for temperature control. We are optimizing temperature-controlled measurement techniques to enable high resolution spectral calibrations using these devices with a Fourier-transform spectrometer.

A High-Voltage Integrated Circuit Engine for a Dielectrophoresis-based Programmable Micro-Fluidic Processor

Science.gov (United States)

Current, K. Wayne; Yuk, Kelvin; McConaghy, Charles; Gascoyne, Peter R. C.; Schwartz, Jon A.; Vykoukal, Jody V.; Andrews, Craig

2010-01-01

A high-voltage (HV) integrated circuit has been demonstrated to transport droplets on programmable paths across its coated surface. This chip is the engine for a dielectrophoresis (DEP)-based micro-fluidic lab-on-a-chip system. This chip creates DEP forces that move and help inject droplets. Electrode excitation voltage and frequency are variable. With the electrodes driven with a 100V peak-to-peak periodic waveform, the maximum high-voltage electrode waveform frequency is about 200Hz. Data communication rate is variable up to 250kHz. This demonstration chip has a 32×32 array of nominally 100V electrode drivers. It is fabricated in a 130V SOI CMOS fabrication technology, dissipates a maximum of 1.87W, and is about 10.4 mm × 8.2 mm. PMID:23989241

Topology optimisation of micro fluidic mixers considering fluid-structure interactions with a coupled Lattice Boltzmann algorithm

Science.gov (United States)

Munk, David J.; Kipouros, Timoleon; Vio, Gareth A.; Steven, Grant P.; Parks, Geoffrey T.

2017-11-01

Recently, the study of micro fluidic devices has gained much interest in various fields from biology to engineering. In the constant development cycle, the need to optimise the topology of the interior of these devices, where there are two or more optimality criteria, is always present. In this work, twin physical situations, whereby optimal fluid mixing in the form of vorticity maximisation is accompanied by the requirement that the casing in which the mixing takes place has the best structural performance in terms of the greatest specific stiffness, are considered. In the steady state of mixing this also means that the stresses in the casing are as uniform as possible, thus giving a desired operating life with minimum weight. The ultimate aim of this research is to couple two key disciplines, fluids and structures, into a topology optimisation framework, which shows fast convergence for multidisciplinary optimisation problems. This is achieved by developing a bi-directional evolutionary structural optimisation algorithm that is directly coupled to the Lattice Boltzmann method, used for simulating the flow in the micro fluidic device, for the objectives of minimum compliance and maximum vorticity. The needs for the exploration of larger design spaces and to produce innovative designs make meta-heuristic algorithms, such as genetic algorithms, particle swarms and Tabu Searches, less efficient for this task. The multidisciplinary topology optimisation framework presented in this article is shown to increase the stiffness of the structure from the datum case and produce physically acceptable designs. Furthermore, the topology optimisation method outperforms a Tabu Search algorithm in designing the baffle to maximise the mixing of the two fluids.

Fabrication of Biochips with Micro Fluidic Channels by Micro End-milling and Powder Blasting

Directory of Open Access Journals (Sweden)

Dong Sam Park

2008-02-01

Full Text Available For microfabrications of biochips with micro fluidic channels, a large number of microfabrication techniques based on silicon or glass-based Micro-Electro-Mechanical System (MEMS technologies were proposed in the last decade. In recent years, for low cost and mass production, polymer-based microfabrication techniques by microinjection molding and micro hot embossing have been proposed. These techniques, which require a proper photoresist, mask, UV light exposure, developing, and electroplating as a preprocess, are considered to have some problems. In this study, we propose a new microfabrication technology which consists of micro end-milling and powder blasting. This technique could be directly applied to fabricate the metal mold without any preprocesses. The metal mold with micro-channels is machined by micro end-milling, and then, burrs generated in the end-milling process are removed by powder blasting. From the experimental results, micro end-milling combined with powder blasting could be applied effectively for fabrication of the injection mold of biochips with micro fluidic channels.

Defect-Induced Photoluminescence Enhancement and Corresponding Transport Degradation in Individual Suspended Carbon Nanotubes

Science.gov (United States)

Wang, Bo; Shen, Lang; Yang, Sisi; Chen, Jihan; Echternach, Juliana; Dhall, Rohan; Kang, DaeJin; Cronin, Stephen

2018-05-01

This paper is a contribution to the Physical Review Applied collection in memory of Mildred S. Dresselhaus. The utilization of defects in carbon nanotubes to improve their photoluminescence efficiency has become a widespread study of the realization of efficient light-emitting devices. Here, we report a detailed comparison of the defects in nanotubes (quantified by Raman spectroscopy) and photoluminescence (PL) intensity of individual suspended carbon nanotubes (CNTs). We also evaluate the impact of these defects on the electron or hole transport in the nanotubes, which is crucial for the ultimate realization of optoelectronic devices. We find that brightly luminescent nanotubes exhibit a pronounced D-band in their Raman spectra, and vice versa, dimly luminescent nanotubes exhibit almost no D-band. Here, defects are advantageous for light emission by trapping excitons, which extend their lifetimes. We quantify this behavior by plotting the PL intensity as a function of the ID /IG -band Raman intensity ratio, which exhibits a Lorentzian distribution peaked at ID /IG=0.17 . For CNTs with a ID /IG ratio >0.25 , the PL intensity decreases, indicating that above some critical density, nonradiative recombination at defect sites dominates over the advantages of exciton trapping. In an attempt to fabricate optoelectronic devices based on these brightly luminescent CNTs, we transfer these suspended CNTs to platinum electrodes and find that the brightly photoluminescent nanotubes exhibit nearly infinite resistance due to these defects, while those without bright photoluminescence exhibit finite resistance. These findings indicate a potential limitation in the use of brightly luminescent CNTs for optoelectronic applications.

Direct spraying method for fabrication of paper-based microfluidic devices

International Nuclear Information System (INIS)

Liu, Ning; An, Hong-Jie; Lew, Wen Siang; Xu, Jing; Phan, Dinh-Tuan; Hashimoto, Michinao

2017-01-01

Direct spraying of hydrophobic materials is an affordable, easy-to-use and equipment-free method for fabrication of flexible microsensors, albeit not yet widely adopted. To explore its application potential, in this paper, we propose and demonstrate two novel hybrid methods to fabricate paper-based components. Firstly, through combing direct spraying with Parafilm embedding, a leak-free paper-based sample preconcentrator for fluorescence sensing was fabricated. The leak-free device worked on the principle of ion concentration polarization (ICP) effect, and achieved enhancement of fluorescent tracer by 220 folds on a paper substrate. Secondly, by using the sprayed hydrophobic patterns, paper-based microsized supercapacitors (mSCs) were fabricated. Vacuum filtration was used to deposit multi-wall carbon nanotubes (MWCNT)-dispersed solution on a porous substrate to form electrodes. A volumetric capacitance of 42.5 mF cm −3 at a current density of 2 mA cm −3 was obtained on the paper-based mSC. Our demonstrations have shown the versatility of direct spraying for the fabrication of integrative paper-based microfluidic devices. (paper)

Nanomechanical cutting of boron nitride nanotubes by atomic force microscopy

International Nuclear Information System (INIS)

Zheng, Meng; Chen, Xiaoming; Ke, Changhong; Park, Cheol; Fay, Catharine C; Pugno, Nicola M

2013-01-01

The length of nanotubes is a critical structural parameter for the design and manufacture of nanotube-based material systems and devices. High-precision length control of nanotubes by means of mechanical cutting using a scriber has not materialized due to the lack of the knowledge of the appropriate cutting conditions and the tube failure mechanism. In this paper, we present a quantitative nanomechanical study of the cutting of individual boron nitride nanotubes (BNNTs) using atomic force microscopy (AFM) probes. In our nanotube cutting measurements, a nanotube standing still on a flat substrate was laterally scribed by an AFM tip. The tip–tube collision force deformed the tube, and eventually fractured the tube at the collision site by increasing the cutting load. The mechanical response of nanotubes during the tip–tube collision process and the roles of the scribing velocity and the frictional interaction on the tip–tube collision contact in cutting nanotubes were quantitatively investigated by cutting double-walled BNNTs of 2.26–4.28 nm in outer diameter. The fracture strength of BNNTs was also quantified based on the measured collision forces and their structural configurations using contact mechanics theories. Our analysis reports fracture strengths of 9.1–15.5 GPa for the tested BNNTs. The nanomechanical study presented in this paper demonstrates that the AFM-based nanomechanical cutting technique not only enables effective control of the length of nanotubes with high precision, but is also promising as a new nanomechanical testing technique for characterizing the mechanical properties of tubular nanostructures. (paper)

Oriented nanotube electrodes for lithium ion batteries and supercapacitors

Science.gov (United States)

Frank, Arthur J.; Zhu, Kai; Wang, Qing

2013-03-05

An electrode having an oriented array of multiple nanotubes is disclosed. Individual nanotubes have a lengthwise inner pore defined by interior tube walls which extends at least partially through the length of the nanotube. The nanotubes of the array may be oriented according to any identifiable pattern. Also disclosed is a device featuring an electrode and methods of fabrication.

Interfacing of DNA with carbon nanotubes for nanodevice applications

International Nuclear Information System (INIS)

Rastogi, Richa; Dhindsa, Navneet; Suri, C. Raman; Pant, B.D.; Tripathi, S.K.; Kaur, Inderpreet; Bharadwaj, Lalit M.

2012-01-01

In nanotechnology, carbon nanotubes are evolving as ‘hot spot’ due to their applications as most sensitive biosensors. Thus, study of effect of biomolecular interaction is prerequisite for their electrical application in biosensors and bioelectronics. Here, we have explored this effect on electrical properties of carbon nanotubes with DNA as a model biomolecule. A stable conjugate of carbon nanotubes with DNA is formed via covalent methodology employing quantum dot as fluoropore and characterized with various spectroscopic, fluoroscopic and microscopic techniques. CNT–DNA adduct showed decreased transconductance (from 614.46 μS to 1.34 μS) and shift of threshold voltage (from −0.85 V to 2.5 V) due to change in Schottky barriers at metal–nanotube contact. In addition, decrease in hole mobility (from 4.46 × 10 6 to 9.72 × 10 3 cm 2 V −1 s −1 ) and increase in ON-linear resistance (from 74 kΩ to 0.44 MΩ) conclude large change in device parameters. On the one hand, this substantial change in device parameters after interfacing with biomolecules supports application of carbon nanotubes in the field of biosensors while on the other hand, the same can limit their use in future power electronic devices where stability in device parameters is essential. -- Graphical abstract: Carbon nanotubes are interfaced with DNA via covalent interactions and characterized with spectroscopic, fluoroscopic and microscopic techniques. Electrical characterization of this stable SWNT–DNA conjugate shows decreased transconductance and shift of threshold voltage towards positive gate voltages. On the one hand, this substantial change in device parameters after interfacing with biomolecules supports application of carbon nanotubes in the field of biosensors while on the other hand, the same can limit their use in future power electronic devices where stability in device parameters is essential. Highlights: ► Effect of biomolecular (DNA) interaction on electrical

A Hydrogel/Carbon-Nanotube Needle-Free Device for Electrostimulated Skin Drug Delivery.

Science.gov (United States)

Guillet, Jean-François; Flahaut, Emmanuel; Golzio, Muriel

2017-10-06

The permeability of skin allows passive diffusion across the epidermis to reach blood vessels but this is possible only for small molecules such as nicotine. In order to achieve transdermal delivery of large molecules such as insulin or plasmid DNA, permeability of the skin and mainly the permeability of the stratum corneum skin layer has to be increased. Moreover, alternative routes that avoid the use of needles will improve the quality of life of patients. A method known as electropermeabilisation has been shown to increase skin permeability. Herein, we report the fabrication of an innovative hydrogel made of a nanocomposite material. This nanocomposite device aims to permeabilise the skin and deliver drug molecules at the same time. It includes a biocompatible polymer matrix (hydrogel) and double-walled carbon nanotubes (DWCNTs) in order to bring electrical conductivity and improve mechanical properties. Carbon nanotubes and especially DWCNTs are ideal candidates, combining high electrical conductivity with a very high specific surface area together with a good biocompatibility when included into a material. The preparation and characterization of the nanocomposite hydrogel as well as first results of electrostimulated transdermal delivery using an ex vivo mouse skin model are presented. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bismuth oxide nanotubes-graphene fiber-based flexible supercapacitors

Science.gov (United States)

Gopalsamy, Karthikeyan; Xu, Zhen; Zheng, Bingna; Huang, Tieqi; Kou, Liang; Zhao, Xiaoli; Gao, Chao

2014-07-01

Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics.Graphene-bismuth oxide nanotube fiber as electrode material for constituting flexible supercapacitors using a PVA/H3PO4 gel electrolyte is reported with a high specific capacitance (Ca) of 69.3 mF cm-2 (for a single electrode) and 17.3 mF cm-2 (for the whole device) at 0.1 mA cm-2, respectively. Our approach opens the door to metal oxide-graphene hybrid fibers and high-performance flexible electronics. Electronic supplementary information (ESI) available: Equations and characterization. SEM images of GGO, XRD and XPS of Bi2O3 NTs, HRTEM images and EDX Spectra of Bi2O3 NT5-GF, CV curves of Bi2O3NT5-GF, Bi2O3 NTs and bismuth nitrate in three-electrode system (vs. Ag/AgCl). CV and GCD curves of Bi2O3 NT1-GF and Bi2O3 NT3-GF. See DOI: 10.1039/c4nr02615b

A biosensor for hydrogen peroxide detection based on electronic properties of carbon nanotubes

Science.gov (United States)

Majidi, Roya

2013-01-01

Density functional theory has been used to study the effect of hydrogen peroxide on the electronic properties of single walled carbon nanotubes. The metallic and semiconducting carbon nanotubes have been considered in the presence of different number of hydrogen peroxide. The results indicate that hydrogen peroxide has no significant effect on the metallic nanotube and these nanotubes remain to be metallic. In contrast, the electronic properties of the semiconducting nanotubes are so sensitive to hydrogen peroxide. The energy band gap of these nanotubes is decreased by increasing the number of hydrogen peroxide. The electronic sensivity of the carbon nanotubes to hydrogen peroxide opens new insights into developing biosensors based on the single walled carbon nanotubes.

Unconventional supercapacitors from nanocarbon-based electrode materials to device configurations.

Science.gov (United States)

Liu, Lili; Niu, Zhiqiang; Chen, Jun

2016-07-25

As energy storage devices, supercapacitors that are also called electrochemical capacitors possess high power density, excellent reversibility and long cycle life. The recent boom in electronic devices with different functions in transparent LED displays, stretchable electronic systems and artificial skin has increased the demand for supercapacitors to move towards light, thin, integrated macro- and micro-devices with transparent, flexible, stretchable, compressible and/or wearable abilities. The successful fabrication of such supercapacitors depends mainly on the preparation of innovative electrode materials and the design of unconventional supercapacitor configurations. Tremendous research efforts have been recently made to design and construct innovative nanocarbon-based electrode materials and supercapacitors with unconventional configurations. We review here recent developments in supercapacitors from nanocarbon-based electrode materials to device configurations. The advances in nanocarbon-based electrode materials mainly include the assembly technologies of macroscopic nanostructured electrodes with different dimensions of carbon nanotubes/nanofibers, graphene, mesoporous carbon, activated carbon, and their composites. The electrodes with macroscopic nanostructured carbon-based materials overcome the issues of low conductivity, poor mechanical properties, and limited dimensions that are faced by conventional methods. The configurational design of advanced supercapacitor devices is presented with six types of unconventional supercapacitor devices: flexible, micro-, stretchable, compressible, transparent and fiber supercapacitors. Such supercapacitors display unique configurations and excellent electrochemical performance at different states such as bending, stretching, compressing and/or folding. For example, all-solid-state simplified supercapacitors that are based on nanostructured graphene composite paper are able to maintain 95% of the original capacity at

Nanoscale memory devices

International Nuclear Information System (INIS)

Chung, Andy; Deen, Jamal; Lee, Jeong-Soo; Meyyappan, M

2010-01-01

This article reviews the current status and future prospects for the use of nanomaterials and devices in memory technology. First, the status and continuing scaling trends of the flash memory are discussed. Then, a detailed discussion on technologies trying to replace flash in the near-term is provided. This includes phase change random access memory, Fe random access memory and magnetic random access memory. The long-term nanotechnology prospects for memory devices include carbon-nanotube-based memory, molecular electronics and memristors based on resistive materials such as TiO 2 . (topical review)

Transparent Electrodes with Nanotubes and Graphene for Printed Optoelectronic Applications

Directory of Open Access Journals (Sweden)

Marcin Słoma

2014-01-01

Full Text Available We report here on printed electroluminescent structures containing transparent electrodes made of carbon nanotubes and graphene nanoplatelets. Screen-printing and spray-coating techniques were employed. Electrodes and structures were examined towards optical parameters using spectrophotometer and irradiation meter. Electromechanical properties of transparent electrodes are exterminated with cyclical bending test. Accelerated aging process was conducted according to EN 62137 standard for reliability tests of electronics. We observed significant negative influence of mechanical bending on sheet resistivity of ITO, while resistivity of nanotube and graphene based electrodes remained stable. Aging process has also negative influence on ITO based structures resulting in delamination of printed layers, while those based on carbon nanomaterials remained intact. We observe negligible changes in irradiation for structures with carbon nanotube electrodes after accelerated aging process. Such materials demonstrate a high application potential in general purpose electroluminescent devices.

Simultaneous pre-concentration and separation on simple paper-based analytical device for protein analysis.

Science.gov (United States)

Niu, Ji-Cheng; Zhou, Ting; Niu, Li-Li; Xie, Zhen-Sheng; Fang, Fang; Yang, Fu-Quan; Wu, Zhi-Yong

2018-02-01

In this work, fast isoelectric focusing (IEF) was successfully implemented on an open paper fluidic channel for simultaneous concentration and separation of proteins from complex matrix. With this simple device, IEF can be finished in 10 min with a resolution of 0.03 pH units and concentration factor of 10, as estimated by color model proteins by smartphone-based colorimetric detection. Fast detection of albumin from human serum and glycated hemoglobin (HBA1c) from blood cell was demonstrated. In addition, off-line identification of the model proteins from the IEF fractions with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was also shown. This PAD IEF is potentially useful either for point of care test (POCT) or biomarker analysis as a cost-effective sample pretreatment method.

Electromechanical interactions in a carbon nanotube based thin film field emitting diode

International Nuclear Information System (INIS)

Sinha, N; Mahapatra, D Roy; Sun, Y; Yeow, J T W; Melnik, R V N; Jaffray, D A

2008-01-01

Carbon nanotubes (CNTs) have emerged as promising candidates for biomedical x-ray devices and other applications of field emission. CNTs grown/deposited in a thin film are used as cathodes for field emission. In spite of the good performance of such cathodes, the procedure to estimate the device current is not straightforward and the required insight towards design optimization is not well developed. In this paper, we report an analysis aided by a computational model and experiments by which the process of evolution and self-assembly (reorientation) of CNTs is characterized and the device current is estimated. The modeling approach involves two steps: (i) a phenomenological description of the degradation and fragmentation of CNTs and (ii) a mechanics based modeling of electromechanical interaction among CNTs during field emission. A computational scheme is developed by which the states of CNTs are updated in a time incremental manner. Finally, the device current is obtained by using the Fowler-Nordheim equation for field emission and by integrating the current density over computational cells. A detailed analysis of the results reveals the deflected shapes of the CNTs in an ensemble and the extent to which the initial state of geometry and orientation angles affect the device current. Experimental results confirm these effects

Nanotubes on Display: How Carbon Nanotubes Can Be Integrated into Electronic Displays

KAUST Repository

Opatkiewicz, Justin

2010-06-22

Random networks of single-walled carbon nanotubes show promise for use in the field of flexible electronics. Nanotube networks have been difficult to utilize because of the mixture of electronic types synthesized when grown. A variety of separation techniques have been developed, but few can readily be scaled up. Despite this issue, when metallic percolation pathways can be separated out or etched away, these networks serve as high-quality thinfilm transistors with impressive device characteristics. A new article in this issue illustrates this point and the promise of these materials. With more work, these devices can be implemented in transparent displays in the next generation of hand-held electronics. © 2010 American Chemical Society.

High-performance radio frequency transistors based on diameter-separated semiconducting carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Cao, Yu; Che, Yuchi; Zhou, Chongwu, E-mail: chongwuz@usc.edu [Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089 (United States); Seo, Jung-Woo T.; Hersam, Mark C. [Department of Materials Science and Engineering and Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Gui, Hui [Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089 (United States)

2016-06-06

In this paper, we report the high-performance radio-frequency transistors based on the single-walled semiconducting carbon nanotubes with a refined average diameter of ∼1.6 nm. These diameter-separated carbon nanotube transistors show excellent transconductance of 55 μS/μm and desirable drain current saturation with an output resistance of ∼100 KΩ μm. An exceptional radio-frequency performance is also achieved with current gain and power gain cut-off frequencies of 23 GHz and 20 GHz (extrinsic) and 65 GHz and 35 GHz (intrinsic), respectively. These radio-frequency metrics are among the highest reported for the carbon nanotube thin-film transistors. This study provides demonstration of radio frequency transistors based on carbon nanotubes with tailored diameter distributions, which will guide the future application of carbon nanotubes in radio-frequency electronics.

A light-stimulated synaptic device based on graphene hybrid phototransistor

Science.gov (United States)

Qin, Shuchao; Wang, Fengqiu; Liu, Yujie; Wan, Qing; Wang, Xinran; Xu, Yongbing; Shi, Yi; Wang, Xiaomu; Zhang, Rong

2017-09-01

Neuromorphic chips refer to an unconventional computing architecture that is modelled on biological brains. They are increasingly employed for processing sensory data for machine vision, context cognition, and decision making. Despite rapid advances, neuromorphic computing has remained largely an electronic technology, making it a challenge to access the superior computing features provided by photons, or to directly process vision data that has increasing importance to artificial intelligence. Here we report a novel light-stimulated synaptic device based on a graphene-carbon nanotube hybrid phototransistor. Significantly, the device can respond to optical stimuli in a highly neuron-like fashion and exhibits flexible tuning of both short- and long-term plasticity. These features combined with the spatiotemporal processability make our device a capable counterpart to today’s electrically-driven artificial synapses, with superior reconfigurable capabilities. In addition, our device allows for generic optical spike processing, which provides a foundation for more sophisticated computing. The silicon-compatible, multifunctional photosensitive synapse opens up a new opportunity for neural networks enabled by photonics and extends current neuromorphic systems in terms of system complexities and functionalities.

Fluidic load control for wind turbines blades

NARCIS (Netherlands)

Boeije, C.S.; Vries, de H.; Cleine, I.; Emden, van E.; Zwart, G.G.M.; Stobbe, H.; Hirschberg, A.; Hoeijmakers, H.W.M.; Maureen Hand, xx

2009-01-01

This paper describes the initial steps into the investigation of the possibility of reducing fatigue loads on wind turbine blades by the application of fluidic jets. This investigation involves static pressure measurements as well as numerical simulations for a non-rotating NACA-0018 airfoil. The

Proton beam writing of long, arbitrary structures for micro/nano photonics and fluidics applications

International Nuclear Information System (INIS)

Udalagama, Chammika; Teo, E.J.; Chan, S.F.; Kumar, V.S.; Bettiol, A.A.; Watt, F.

2011-01-01

The last decade has seen proton beam writing maturing into a versatile lithographic technique able to produce sub-100 nm, high aspect ratio structures with smooth side walls. However, many applications in the fields of photonics and fluidics require the fabrication of structures with high spatial resolution that extends over several centimetres. This cannot be achieved by purely magnetic or electrostatic beam scanning due to the large off-axis beam aberrations in high demagnification systems. As a result, this has limited us to producing long straight structures using a combination of beam and stage scanning. In this work we have: (1) developed an algorithm to include any arbitrary pattern into the writing process by using a more versatile combination of beam and stage scanning while (2) incorporating the use of the ubiquitous AutoCAD DXF (drawing exchange format) into the design process. We demonstrate the capability of this approach in fabricating structures such as Y-splitters, Mach-Zehnder modulators and microfluidic channels that are over several centimetres in length, in polymer. We also present optimisation of such parameters as scanning speed and scanning loops to improve on the surface roughness of the structures. This work opens up new possibilities of using CAD software in PBW for microphotonics and fluidics device fabrication.

Proton beam writing of long, arbitrary structures for micro/nano photonics and fluidics applications

Science.gov (United States)

Udalagama, Chammika; Teo, E. J.; Chan, S. F.; Kumar, V. S.; Bettiol, A. A.; Watt, F.

2011-10-01

The last decade has seen proton beam writing maturing into a versatile lithographic technique able to produce sub-100 nm, high aspect ratio structures with smooth side walls. However, many applications in the fields of photonics and fluidics require the fabrication of structures with high spatial resolution that extends over several centimetres. This cannot be achieved by purely magnetic or electrostatic beam scanning due to the large off-axis beam aberrations in high demagnification systems. As a result, this has limited us to producing long straight structures using a combination of beam and stage scanning. In this work we have: (1) developed an algorithm to include any arbitrary pattern into the writing process by using a more versatile combination of beam and stage scanning while (2) incorporating the use of the ubiquitous AutoCAD DXF (drawing exchange format) into the design process. We demonstrate the capability of this approach in fabricating structures such as Y-splitters, Mach-Zehnder modulators and microfluidic channels that are over several centimetres in length, in polymer. We also present optimisation of such parameters as scanning speed and scanning loops to improve on the surface roughness of the structures. This work opens up new possibilities of using CAD software in PBW for microphotonics and fluidics device fabrication.

Proton beam writing of long, arbitrary structures for micro/nano photonics and fluidics applications

Energy Technology Data Exchange (ETDEWEB)

Udalagama, Chammika, E-mail: chammika@nus.edu.sg [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore 117542 (Singapore); Teo, E.J. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore 117542 (Singapore); Chan, S.F. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore 117542 (Singapore); NUS Nanoscience and Nanotechnology Initiative, 2 Science Drive 3, 117542 (Singapore); Department of Chemistry, NUS, 3 Science Drive 3, 117543 (Singapore); Kumar, V.S.; Bettiol, A.A.; Watt, F. [Centre for Ion Beam Applications (CIBA), Department of Physics, National University of Singapore (NUS), 2 Science Drive 3, Singapore 117542 (Singapore)

2011-10-15

The last decade has seen proton beam writing maturing into a versatile lithographic technique able to produce sub-100 nm, high aspect ratio structures with smooth side walls. However, many applications in the fields of photonics and fluidics require the fabrication of structures with high spatial resolution that extends over several centimetres. This cannot be achieved by purely magnetic or electrostatic beam scanning due to the large off-axis beam aberrations in high demagnification systems. As a result, this has limited us to producing long straight structures using a combination of beam and stage scanning. In this work we have: (1) developed an algorithm to include any arbitrary pattern into the writing process by using a more versatile combination of beam and stage scanning while (2) incorporating the use of the ubiquitous AutoCAD DXF (drawing exchange format) into the design process. We demonstrate the capability of this approach in fabricating structures such as Y-splitters, Mach-Zehnder modulators and microfluidic channels that are over several centimetres in length, in polymer. We also present optimisation of such parameters as scanning speed and scanning loops to improve on the surface roughness of the structures. This work opens up new possibilities of using CAD software in PBW for microphotonics and fluidics device fabrication.

Preparation and Testing of Impedance-based Fluidic Biochips with RTgill-W1 Cells for Rapid Evaluation of Drinking Water Samples for Toxicity

Science.gov (United States)

2016-03-07

109 | e53555 | Page 1 of 8 Video Article Preparation and Testing of Impedance-based Fluidic Biochips with RTgill-W1 Cells for Rapid Evaluation of...www.jove.com/ video /53555 DOI: doi:10.3791/53555 Keywords: Environmental Sciences, Issue 109, Fish cells, impedance, sensors, biochip, water toxicity...sensitivity to cholinesterase-inhibiting pesticides . Applications for this toxicity detector are for rapid field-portable testing of drinking water

Recent results of the investigation of a micro-fluidic sampling chip and sampling system for hot cell aqueous processing streams

International Nuclear Information System (INIS)

Tripp, J.; Smith, T.; Law, J.

2013-01-01

A Fuel Cycle Research and Development project has investigated an innovative sampling method that could evolve into the next generation sampling and analysis system for metallic elements present in aqueous processing streams. Initially sampling technologies were evaluated and micro-fluidic sampling chip technology was selected and tested. A conceptual design for a fully automated microcapillary-based system was completed and a robotic automated sampling system was fabricated. The mechanical and sampling operation of the completed sampling system was investigated. Different sampling volumes have been tested. It appears that the 10 μl volume has produced data that had much smaller relative standard deviations than the 2 μl volume. In addition, the production of a less expensive, mass produced sampling chip was investigated to avoid chip reuse thus increasing sampling reproducibility/accuracy. The micro-fluidic-based robotic sampling system's mechanical elements were tested to ensure analytical reproducibility and the optimum robotic handling of micro-fluidic sampling chips. (authors)

Current-induced changes of migration energy barriers in graphene and carbon nanotubes

Science.gov (United States)

Obodo, J. T.; Rungger, I.; Sanvito, S.; Schwingenschlögl, U.

2016-05-01

An electron current can move atoms in a nanoscale device with important consequences for the device operation and breakdown. We perform first principles calculations aimed at evaluating the possibility of changing the energy barriers for atom migration in carbon-based systems. In particular, we consider the migration of adatoms and defects in graphene and carbon nanotubes. Although the current-induced forces are large for both the systems, in graphene the force component along the migration path is small and therefore the barrier height is little affected by the current flow. In contrast, the same barrier is significantly reduced in carbon nanotubes as the current increases. Our work also provides a real-system numerical demonstration that current-induced forces within density functional theory are non-conservative.An electron current can move atoms in a nanoscale device with important consequences for the device operation and breakdown. We perform first principles calculations aimed at evaluating the possibility of changing the energy barriers for atom migration in carbon-based systems. In particular, we consider the migration of adatoms and defects in graphene and carbon nanotubes. Although the current-induced forces are large for both the systems, in graphene the force component along the migration path is small and therefore the barrier height is little affected by the current flow. In contrast, the same barrier is significantly reduced in carbon nanotubes as the current increases. Our work also provides a real-system numerical demonstration that current-induced forces within density functional theory are non-conservative. Electronic supplementary information (ESI) available. See DOI: 10.1039/C6NR00534A

Selective growth of carbon nanotube on silicon substrates

Institute of Scientific and Technical Information of China (English)

ZOU Xiao-ping; H. ABE; T. SHIMIZU; A. ANDO; H. TOKUMOT; ZHU Shen-ming; ZHOU Hao-shen

2006-01-01

The carbon nanotube (CNT) growth of iron oxide-deposited trench-patterns and the locally-ordered CNT arrays on silicon substrate were achieved by simple thermal chemical vapor deposition(STCVD) of ethanol vapor. The CNTs were uniformly synthesized with good selectivity on trench-patterned silicon substrates. This fabrication process is compatible with currently used semiconductor-processing technologies,and the carbon-nanotube fabrication process can be widely applied for the development of electronic devices using carbon-nanotube field emitters as cold cathodes and can revolutionize the area of field-emitting electronic devices. The site-selective growth of CNT from an iron oxide nanoparticle catalyst patterned were also achieved by drying-mediated self-assembly technique. The present method offers a simple and cost-effective method to grow carbon nanotubes with self-assembled patterns.

Electrostatically telescoping nanotube nonvolatile memory device

International Nuclear Information System (INIS)

Kang, Jeong Won; Jiang Qing

2007-01-01

We propose a nonvolatile memory based on carbon nanotubes (CNTs) serving as the key building blocks for molecular-scale computers and investigate the dynamic operations of a double-walled CNT memory element by classical molecular dynamics simulations. The localized potential energy wells achieved from both the interwall van der Waals energy and CNT-metal binding energy make the bistability of the CNT positions and the electrostatic attractive forces induced by the voltage differences lead to the reversibility of this CNT memory. The material for the electrodes should be carefully chosen to achieve the nonvolatility of this memory. The kinetic energy of the CNT shuttle experiences several rebounds induced by the collisions of the CNT onto the metal electrodes, and this is critically important to the performance of such an electrostatically telescoping CNT memory because the collision time is sufficiently long to cause a delay of the state transition

Fluidic origami cellular structure -- combining the plant nastic movements with paper folding art

Science.gov (United States)

Li, Suyi; Wang, K. W.

2015-04-01

By combining the physical principles behind the nastic plant movements and the rich designs of paper folding art, we propose a new class of multi-functional adaptive structure called fluidic origami cellular structure. The basic elements of this structure are fluid filled origami "cells", made by connecting two compatible Miura-Ori stripes along their crease lines. These cells are assembled seamlessly into a three dimensional topology, and their internal fluid pressure or volume are strategically controlled just like in plants for nastic movements. Because of the unique geometry of the Miura-Ori, the relationships among origami folding, internal fluid properties, and the crease bending are intricate and highly nonlinear. Fluidic origami can exploit such relationships to provide multiple adaptive functions concurrently and effectively. For example, it can achieve actuation or morphing by actively changing the internal fluid volume, and stillness tuning by constraining the fluid volume. Fluidic origami can also be bistable because of the nonlinear correlation between folding and crease material bending, and such bistable character can be altered significantly by fluid pressurization. These functions are natural and essential companions with respect to each other, so that fluidic origami can holistically exhibit many attractive characteristics of plants and deliver rapid and efficient actuation/morphing while maintaining a high structural stillness. The purpose of this paper is to introduce the design and working principles of the fluidic origami, as well as to explore and demonstrate its performance potential.

Electrochemical biosensing based on polypyrrole/titania nanotube hybrid

Energy Technology Data Exchange (ETDEWEB)

Xie, Yibing, E-mail: ybxie@seu.edu.cn; Zhao, Ye

2013-12-01

The glucose oxidase (GOD) modified polypyrrole/titania nanotube enzyme electrode is fabricated for electrochemical biosensing application. The titania nanotube array is grown directly on a titanium substrate through an anodic oxidation process. A thin film of polypyrrole is coated onto titania nanotube array to form polypyrrole/titania nanotube hybrid through a normal pulse voltammetry process. GOD-polypyrrole/titania nanotube enzyme electrode is prepared by the covalent immobilization of GOD onto polypyrrole/titania nanotube hybrid via the cross-linker of glutaraldehyde. The morphology and microstructure of nanotube electrodes are characterized by field emission scanning electron microscopy and Fourier transform infrared analysis. The biosensing properties of this nanotube enzyme electrode have been investigated by means of cyclic voltammetry and chronoamperometry. The hydrophilic polypyrrole/titania nanotube hybrid provides highly accessible nanochannels for GOD encapsulation, presenting good enzymatic affinity. As-formed GOD-polypyrrole/titania nanotube enzyme electrode well conducts bioelectrocatalytic oxidation of glucose, exhibiting a good biosensing performance with a high sensitivity, low detection limit and wide linear detection range. - Graphical abstract: The schematic diagram presents the fabrication of glucose oxidase modified polypyrrole/titania (GOD-PPy/TiO{sub 2}) nanotube enzyme electrode for biosensing application. - Highlights: • Hydrophilic polypyrrole/titania nanotube hybrid is well used as biosensing substrate. • Polypyrrole promotes GOD immobilization on titania nanotubes via glutaraldehyde. • GOD-polypyrrole/titania enzyme electrode shows good bioelectrocatalytic reactivity.

Electrochemical biosensing based on polypyrrole/titania nanotube hybrid

International Nuclear Information System (INIS)

Xie, Yibing; Zhao, Ye

2013-01-01

The glucose oxidase (GOD) modified polypyrrole/titania nanotube enzyme electrode is fabricated for electrochemical biosensing application. The titania nanotube array is grown directly on a titanium substrate through an anodic oxidation process. A thin film of polypyrrole is coated onto titania nanotube array to form polypyrrole/titania nanotube hybrid through a normal pulse voltammetry process. GOD-polypyrrole/titania nanotube enzyme electrode is prepared by the covalent immobilization of GOD onto polypyrrole/titania nanotube hybrid via the cross-linker of glutaraldehyde. The morphology and microstructure of nanotube electrodes are characterized by field emission scanning electron microscopy and Fourier transform infrared analysis. The biosensing properties of this nanotube enzyme electrode have been investigated by means of cyclic voltammetry and chronoamperometry. The hydrophilic polypyrrole/titania nanotube hybrid provides highly accessible nanochannels for GOD encapsulation, presenting good enzymatic affinity. As-formed GOD-polypyrrole/titania nanotube enzyme electrode well conducts bioelectrocatalytic oxidation of glucose, exhibiting a good biosensing performance with a high sensitivity, low detection limit and wide linear detection range. - Graphical abstract: The schematic diagram presents the fabrication of glucose oxidase modified polypyrrole/titania (GOD-PPy/TiO 2 ) nanotube enzyme electrode for biosensing application. - Highlights: • Hydrophilic polypyrrole/titania nanotube hybrid is well used as biosensing substrate. • Polypyrrole promotes GOD immobilization on titania nanotubes via glutaraldehyde. • GOD-polypyrrole/titania enzyme electrode shows good bioelectrocatalytic reactivity

Development of an opto-fluidic micro-system dedicated to chemical analysis in a nuclear environment

Energy Technology Data Exchange (ETDEWEB)

Geoffray, F.; Canto, F.; Couston, L. [CEA, Centre de Marcoule, Nuclear Energy Division, RadioChemistry and Processes Department, SERA/LAMM, F-30207 Bagnols-sur-Ceze (France); Allenet, T.; Bucci, D.; Broquin, J.E. [IMEP-LaHC, Universite de Grenoble Alpes, UMR 5130 CNRS, Minatec-Grenoble-INP, CS 50257, 38016 Grenoble (France); Jardinier, E. [CEA, Centre de Marcoule, Nuclear Energy Division, RadioChemistry and Processes Department, SERA/LAMM, F-30207 Bagnols-sur-Ceze (France); IMEP-LaHC, Universite de Grenoble Alpes, UMR 5130 CNRS, Minatec-Grenoble-INP, CS 50257, 38016 Grenoble (France)

2016-07-01

Micromachining techniques enable the fabrication of innovative lab-on-a-chip. Following the trend in chemical and biological analysis, the use of microsystems also appears compelling in the nuclear industry. The volume reduction of radioactive solutions is especially attractive in order to reduce the workers radiation exposition in the context of off-line analysis in spent nuclear fuel reprocessing plants. We hence present the development of an opto-fluidic sensor combining micro-fluidic channels for fluid transportation and integrated optics for detection. With the aim of achieving automated microanalysis with reduced response time the sensor is made compatible with a commercial micro-fluidic holder. Therefore the chip is connected to computer controlled pumps and electro-valves thanks to capillary tubing. In this paper we emphasis on the fluid handling capacities of the opto-fluidic sensor. (authors)

Asymmetric electrochemical supercapacitor, based on polypyrrole coated carbon nanotube electrodes

International Nuclear Information System (INIS)

Su, Y.; Zhitomirsky, I.

2015-01-01

Highlights: • Polypyrrole (PPy) coated multiwalled carbon nanotubes (MWCNT) were prepared. • New method is based on the use of new electrochemically active dopants for PPy. • The dopans provided dispersion of MWCNT and promoted PPy coating formation. • Symmetric PPy–MWCNT supercapacitors showed high capacitance and low resistance. • Asymmetric PPy–MWCNT/VN–MWCNT devices and modules allowed larger voltage window. - Abstract: Conductive polypyrrole (PPy) polymer – multiwalled carbon nanotubes (MWCNT) composites were synthesized using sulfanilic acid azochromotrop (SPADNS) and sulfonazo III sodium salt (CHR-BS) as anionic dopants for chemical polymerization of PPy. The composites were tested for application in electrodes of electrochemical supercapacitors (ES). Sedimentation tests, electrophoretic deposition experiments and Fourier transform infrared spectroscopy (FTIR) investigations showed that strong adsorption of anionic CHR-BS on MWCNT provided MWCNT dispersion. The analysis of scanning and transmission electron microscopy data demonstrated that the use of CHR-BS allowed the formation of PPy coatings on MWCNT. As a result, the composites, prepared using CHR-BS, showed higher capacitance, compared to the composites, prepared using SPADNS. The electrodes, containing MWCNT, coated with PPy showed a capacitance of 179 F g −1 for active mass loading of 10 mg cm −2 , good capacitance retention at scan rates in the range of 2–100 mV s −1 and excellent cyclic stability. Asymmetric ES devices, containing positive PPy–MWCNT electrodes and negative vanadium nitride (VN)–MWCNT electrodes showed significant improvement in energy storage performance, compared to the symmetric ES due to the larger voltage window. The low impedance and high capacitance of the individual cells paved the way to the development of modules with higher voltage, which showed good electrochemical performance

A carbon nanotube-based pressure sensor

International Nuclear Information System (INIS)

Karimov, Kh S; Saleem, M; Khan, Adam; Qasuria, T A; Mateen, A; Karieva, Z M

2011-01-01

In this study, a carbon nanotube (CNT)-based Al/CNT/Al pressure sensor was designed, fabricated and investigated. The sensor was fabricated by depositing CNTs on an adhesive elastic polymer tape and placing this in an elastic casing. The diameter of multiwalled nanotubes varied between 10 and 30 nm. The nominal thickness of the CNT layers in the sensors was in the range ∼300-430 μm. The inter-electrode distance (length) and the width of the surface-type sensors were in the ranges 4-6 and 3-4 mm, respectively. The dc resistance of the sensors decreased 3-4 times as the pressure was increased up to 17 kN m -2 . The resistance-pressure relationships were simulated.

Biochips Containing Arrays of Carbon-Nanotube Electrodes

Science.gov (United States)

Li, Jun; Meyyappan, M.; Koehne, Jessica; Cassell, Alan; Chen, Hua

2008-01-01

Biochips containing arrays of nanoelectrodes based on multiwalled carbon nanotubes (MWCNTs) are being developed as means of ultrasensitive electrochemical detection of specific deoxyribonucleic acid (DNA) and messenger ribonucleic acid (mRNA) biomarkers for purposes of medical diagnosis and bioenvironmental monitoring. In mass production, these biochips could be relatively inexpensive (hence, disposable). These biochips would be integrated with computer-controlled microfluidic and microelectronic devices in automated hand-held and bench-top instruments that could be used to perform rapid in vitro genetic analyses with simplified preparation of samples. Carbon nanotubes are attractive for use as nanoelectrodes for detection of biomolecules because of their nanoscale dimensions and their chemical properties.

Micro Machining of Injection Mold Inserts for Fluidic Channel of Polymeric Biochips

Directory of Open Access Journals (Sweden)

Myeong-Woo Cho

2007-08-01

Full Text Available Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip, has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for micro-fluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

Evaluation on thermal-hydraulic characteristics for passive safety device of APR1400

Energy Technology Data Exchange (ETDEWEB)

Yoo, Seong Yeon; Lee, S. H.; Son, M. K. [Korea Association for Nuclear Technology, Taejon (Korea, Republic of); Jee, M. S.; Chung, M. H. [Chungnam National Univ., Taejon (Korea, Republic of)

2001-07-15

To establish evaluation and verification guideline for the APR1400, thermal-hydraulic characteristics for fuel rod bundle, reactor vessel and fluidic device is analyzed using FLUENT. Scope and major results of research are as follows : Thermal-hydraulic characteristics for nuclear fuel rod bundle: design data for nuclear fuel rod bundle and structure are surveyed, and 3 x 3 sub-channel model is adopted to investigate the fluid flow and heat transfer characteristics in fuel rod bundle. Computational results are compared with the heat transfer data measured by naphthalene sublimation method, and numerical analysis and evaluation are performed at various design conditions and flow conditions. Thermal-hydraulic characteristics for reactor vessel: reactor vessel design data are surveyed to develop numerical model. Porous media model is applied for fuel rod bundle, and full-scale, three dimensional simulation is performed at actual operating conditions. Distributions of velocity, pressure and temperature are discussed. Flow characteristics for fluidic device: three dimensional numerical model for fluidic device is developed, and numerical results are compared with experimental data obtained at KAERI in order to verify numerical simulation. In addition, variation of flow rate is investigated at various elapsed times after valve operating, and flow characteristics is analyzed at low and high flow rate conditions, respectively.

Interfacing of DNA with carbon nanotubes for nanodevice applications

Energy Technology Data Exchange (ETDEWEB)

Rastogi, Richa, E-mail: richa.bend@gmail.com [Biomolecular Electronics and Nanotechnology Division (BEND), Central Scientific Instruments Organisation (CSIO), Sector-30C, Chandigarh 160030 (India); Centre of Advanced Studies in Physics, Punjab University, Sector-14, Chandigarh 160014 (India); Dhindsa, Navneet [Biomolecular Electronics and Nanotechnology Division (BEND), Central Scientific Instruments Organisation (CSIO), Sector-30C, Chandigarh 160030 (India); Suri, C. Raman [Biosensor Division, Institute of Microbial Technology (IMTECH), Sector-39, Chandigarh 160039 (India); Pant, B.D. [Central Electronics Engineering Research Institute, Pilani, Rajasthan (India); Tripathi, S.K. [Centre of Advanced Studies in Physics, Punjab University, Sector-14, Chandigarh 160014 (India); Kaur, Inderpreet; Bharadwaj, Lalit M. [Biomolecular Electronics and Nanotechnology Division (BEND), Central Scientific Instruments Organisation (CSIO), Sector-30C, Chandigarh 160030 (India)

2012-08-15

In nanotechnology, carbon nanotubes are evolving as 'hot spot' due to their applications as most sensitive biosensors. Thus, study of effect of biomolecular interaction is prerequisite for their electrical application in biosensors and bioelectronics. Here, we have explored this effect on electrical properties of carbon nanotubes with DNA as a model biomolecule. A stable conjugate of carbon nanotubes with DNA is formed via covalent methodology employing quantum dot as fluoropore and characterized with various spectroscopic, fluoroscopic and microscopic techniques. CNT-DNA adduct showed decreased transconductance (from 614.46 {mu}S to 1.34 {mu}S) and shift of threshold voltage (from -0.85 V to 2.5 V) due to change in Schottky barriers at metal-nanotube contact. In addition, decrease in hole mobility (from 4.46 Multiplication-Sign 10{sup 6} to 9.72 Multiplication-Sign 10{sup 3} cm{sup 2} V{sup -1} s{sup -1}) and increase in ON-linear resistance (from 74 k Ohm-Sign to 0.44 M Ohm-Sign ) conclude large change in device parameters. On the one hand, this substantial change in device parameters after interfacing with biomolecules supports application of carbon nanotubes in the field of biosensors while on the other hand, the same can limit their use in future power electronic devices where stability in device parameters is essential. -- Graphical abstract: Carbon nanotubes are interfaced with DNA via covalent interactions and characterized with spectroscopic, fluoroscopic and microscopic techniques. Electrical characterization of this stable SWNT-DNA conjugate shows decreased transconductance and shift of threshold voltage towards positive gate voltages. On the one hand, this substantial change in device parameters after interfacing with biomolecules supports application of carbon nanotubes in the field of biosensors while on the other hand, the same can limit their use in future power electronic devices where stability in device parameters is essential

Flow-Regulated Growth of Titanium Dioxide (TiO2 ) Nanotubes in Microfluidics.

Science.gov (United States)

Fan, Rong; Chen, Xinye; Wang, Zihao; Custer, David; Wan, Jiandi

2017-08-01

Electrochemical anodization of titanium (Ti) in a static, bulk condition is used widely to fabricate self-organized TiO 2 nanotube arrays. Such bulk approaches, however, require extended anodization times to obtain long TiO 2 nanotubes and produce only vertically aligned nanotubes. To date, it remains challenging to develop effective strategies to grow long TiO 2 nanotubes in a short period of time, and to control the nanotube orientation. Here, it is shown that the anodic growth of TiO 2 nanotubes is significantly enhanced (≈16-20 times faster) under flow conditions in microfluidics. Flow not only controls the diameter, length, and crystal orientations of TiO 2 nanotubes, but also regulates the spatial distribution of nanotubes inside microfluidic devices. Strikingly, when a Ti thin film is deposited on silicon substrates and anodized in microfluidics, both vertically and horizontally aligned (relative to the bottom substrate) TiO 2 nanotubes can be produced. The results demonstrate previously unidentified roles of flow in the regulation of growth of TiO 2 nanotubes, and provide powerful approaches to effectively grow long, oriented TiO 2 nanotubes, and construct hierarchical TiO 2 nanotube arrays on silicon-based materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication and characterization of PEDOT nanowires based on self-assembled peptide nanotube lithography

DEFF Research Database (Denmark)

Andersen, Karsten Brandt; Christiansen, Nikolaj Ormstrup; Castillo, Jaime

2013-01-01

In this article we demonstrate the use of self-assembled peptide nanotube structures as masking material in a rapid, mild and low cost fabrication of polymerized p-toluenesulfonate doped poly(3,4-ethylenedioxythiophene) (PEDOT:TsO) nanowire device. In this new fabrication approach the PEDOT:TsO n...

Sample preparation and detection device for infectious agents

Science.gov (United States)

Miles, Robin R.; Wang, Amy W.; Fuller, Christopher K.; Lemoff, Asuncion V.; Bettencourt, Kerry A.; Yu, June

2003-06-10

A sample preparation and analysis device which incorporates both immunoassays and PCR assays in one compact, field-portable microchip. The device provides new capabilities in fluid and particle control which allows the building of a fluidic chip with no moving parts, thus decreasing fabrication cost and increasing the robustness of the device. The device can operate in a true continuous (not batch) mode. The device incorporates magnetohydrodynamic (MHD) pumps to move the fluid through the system, acoustic mixing and fractionation, dielectropheretic (DEP) sample concentration and purification, and on-chip optical detection capabilities.

Dielectric elastomer strain and pressure sensing enable reactive soft fluidic muscles

Science.gov (United States)

Veale, Allan J.; Anderson, Iain A.; Xie, Sheng Q.

2016-04-01

Wearable assistive devices are the future of rehabilitation therapy and bionic limb technologies. Traditional electric, hydraulic, and pneumatic actuators can provide the precise and powerful around-the-clock assistance that therapists cannot deliver. However, they do so in the confines of highly controlled factory environments, resulting in actuators too rigid, heavy, and immobile for wearable applications. In contrast, biological skeletal muscles have been designed and proven in the uncertainty of the real world. Bioinspired artificial muscle actuators aim to mimic the soft, slim, and self-sensing abilities of natural muscle that make them tough and intelligent. Fluidic artificial muscles are a promising wearable assistive actuation candidate, sharing the high-force, inherent compliance of their natural counterparts. Until now, they have not been able to self-sense their length, pressure, and force in an entirely soft and flexible system. Their use of rigid components has previously been a requirement for the generation of large forces, but reduces their reliability and compromises their ability to be comfortably worn. We present the unobtrusive integration of dielectric elastomer (DE) strain and pressure sensors into a soft Peano fluidic muscle, a planar alternative to the relatively bulky McKibben muscle. Characterization of these DE sensors shows they can measure the full operating range of the Peano muscle: strains of around 18% and pressures up to 400 kPa with changes in capacitance of 2.4 and 10.5 pF respectively. This is a step towards proprioceptive artificial muscles, paving the way for wearable actuation that can truly feel its environment.

Electron beam and mechanical lithographies as enabling factors for organic-based device fabrication

International Nuclear Information System (INIS)

Visconti, P.; Pisignano, D.; Della Torre, A.; Persano, L.; Maruccio, G.; Biasco, A.; Cingolani, R.; Rinaldi, R.

2005-01-01

Organic-based photonics and molecular electronics are attracting an increasing interest in modern science. The realization of high-resolution master structures by electron beam lithography (EBL) and their transfer to different organic functional materials by mechanical lithographies allow to fully exploit the wide flexibility of molecular systems for opto- and nanoelectronic devices. Planar nanojunctions, consisting of two metallic electrodes separated by an insulating medium, permit to test the molecular conduction properties. Since the typical size of a biomolecule is of the order of a few nanometer, hybrid molecular electronic (HME) devices need metallic electrodes separated by a nanometer-scale channel. Conversely, photonic applications often require 100 nm to 1 μm features on large areas. In this work, we report on the fabrication of both large-area periodic master structures with resolution down to 200 nm, and planar metallic electrodes with sub-10 nm separation obtained by EBL followed by metal electroplating deposition. The fabricated 3-terminal bio-nanodevices show a transistor-like behaviour with a maximum voltage gain of 0.76. Moreover, we developed a number of mechanical patterning methods, including soft hot embossing, rapid prototyping, sub-micrometer fluidics, high- and room-temperature nanoimprinting, to fabricate planar nanostructures on both biomolecular and organic materials. These allowed us a high-fidelity pattern transfer up to 100-nm scale resolution, without reducing the emission yields of light-emitting organics, thus opening the way to the one-step realization of organic-based confined optoelectronic devices

Phononic fluidics: acoustically activated droplet manipulations

Science.gov (United States)

Reboud, Julien; Wilson, Rab; Bourquin, Yannyk; Zhang, Yi; Neale, Steven L.; Cooper, Jonathan M.

2011-02-01

Microfluidic systems have faced challenges in handling real samples and the chip interconnection to other instruments. Here we present a simple interface, where surface acoustic waves (SAWs) from a piezoelectric device are coupled into a disposable acoustically responsive microfluidic chip. By manipulating droplets, SAW technologies have already shown their potential in microfluidics, but it has been limited by the need to rely upon mixed signal generation at multiple interdigitated electrode transducers (IDTs) and the problematic resulting reflections, to allow complex fluid operations. Here, a silicon chip was patterned with phononic structures, engineering the acoustic field by using a full band-gap. It was simply coupled to a piezoelectric LiNbO3 wafer, propagating the SAW, via a thin film of water. Contrary to the use of unstructured superstrates, phononic metamaterials allowed precise spatial control of the acoustic energy and hence its interaction with the liquids placed on the surface of the chip, as demonstrated by simulations. We further show that the acoustic frequency influences the interaction between the SAW and the phononic lattice, providing a route to programme complex fluidic manipulation onto the disposable chip. The centrifugation of cells from a blood sample is presented as a more practical demonstration of the potential of phononic crystals to realize diagnostic systems.

Self-assembly of protein-based biomaterials initiated by titania nanotubes.

Science.gov (United States)

Forstater, Jacob H; Kleinhammes, Alfred; Wu, Yue

2013-12-03

Protein-based biomaterials are a promising strategy for creating robust highly selective biocatalysts. The assembled biomaterials must sufficiently retain the near-native structure of proteins and provide molecular access to catalytically active sites. These requirements often exclude the use of conventional assembly techniques, which rely on covalent cross-linking of proteins or entrapment within a scaffold. Here we demonstrate that titania nanotubes can initiate and template the self-assembly of enzymes, such as ribonuclease A, while maintaining their catalytic activity. Initially, the enzymes form multilayer thick ellipsoidal aggregates centered on the nanotube surface; subsequently, these nanosized entities assemble into a micrometer-sized enzyme material that has enhanced enzymatic activity and contains as little as 0.1 wt % TiO2 nanotubes. This phenomenon is uniquely associated with the active anatase (001)-like surface of titania nanotubes and does not occur on other anatase nanomaterials, which contain significantly fewer undercoordinated Ti surface sites. These findings present a nanotechnology-enabled mechanism of biomaterial growth and open a new route for creating stable protein-based biomaterials and biocatalysts without the need for chemical modification.

Multifunctional Carbon Nanotube-Based Sensors for Damage Detection and Self Healing in Structural Composites

Science.gov (United States)

2010-10-29

established based on the concept of equipotential surface . The effect of nanotube length on the critical charge level is plotted in Fig. 17. Fig...walled carbon nanotubes was used to develop composites with agglomerated regions of nanotubes at the fiber surface [3]. An image of the nanotube...coating on the surface of two E-glass fibers is shown in Fig. 5. Fig. 5. (a) Carbon nanotube agglomerates on the surface of glass fibers in the

Inkjet printed ambipolar transistors and inverters based on carbon nanotube/zinc tin oxide heterostructures

International Nuclear Information System (INIS)

Kim, Bongjun; Jang, Seonpil; Dodabalapur, Ananth; Geier, Michael L.; Prabhumirashi, Pradyumna L.; Hersam, Mark C.

2014-01-01

We report ambipolar field-effect transistors (FETs) consisting of inkjet printed semiconductor bilayer heterostructures utilizing semiconducting single-walled carbon nanotubes (SWCNTs) and amorphous zinc tin oxide (ZTO). The bilayer structure allows for electron transport to occur principally in the amorphous oxide layer and hole transport to occur exclusively in the SWCNT layer. This results in balanced electron and hole mobilities exceeding 2 cm 2 V −1 s −1 at low operating voltages ( 10). This work provides a pathway for realizing solution processable, inkjet printable, large area electronic devices, and systems based on SWCNT-amorphous oxide heterostructures

Multi-chamber nucleic acid amplification and detection device

Science.gov (United States)

Dugan, Lawrence

2017-10-25

A nucleic acid amplification and detection device includes an amplification cartridge with a plurality of reaction chambers for containing an amplification reagent and a visual detection reagent, and a plurality of optically transparent view ports for viewing inside the reaction chambers. The cartridge also includes a sample receiving port which is adapted to receive a fluid sample and fluidically connected to distribute the fluid sample to the reaction chamber, and in one embodiment, a plunger is carried by the cartridge for occluding fluidic communication to the reaction chambers. The device also includes a heating apparatus having a heating element which is activated by controller to generate heat when a trigger event is detected. The heating apparatus includes a cartridge-mounting section which positioned a cartridge in thermal communication with the heating element so that visual changes to the contents of the reaction chambers are viewable through the view ports.

Remote Joule heating by a carbon nanotube.

Science.gov (United States)

Baloch, Kamal H; Voskanian, Norvik; Bronsgeest, Merijntje; Cumings, John

2012-04-08

Minimizing Joule heating remains an important goal in the design of electronic devices. The prevailing model of Joule heating relies on a simple semiclassical picture in which electrons collide with the atoms of a conductor, generating heat locally and only in regions of non-zero current density, and this model has been supported by most experiments. Recently, however, it has been predicted that electric currents in graphene and carbon nanotubes can couple to the vibrational modes of a neighbouring material, heating it remotely. Here, we use in situ electron thermal microscopy to detect the remote Joule heating of a silicon nitride substrate by a single multiwalled carbon nanotube. At least 84% of the electrical power supplied to the nanotube is dissipated directly into the substrate, rather than in the nanotube itself. Although it has different physical origins, this phenomenon is reminiscent of induction heating or microwave dielectric heating. Such an ability to dissipate waste energy remotely could lead to improved thermal management in electronic devices.

Lab on a Biomembrane: Rapid prototyping and manipulation of 2D fluidic lipid bilayers circuits

Science.gov (United States)

Ainla, Alar; Gözen, Irep; Hakonen, Bodil; Jesorka, Aldo

2013-01-01

Lipid bilayer membranes are among the most ubiquitous structures in the living world, with intricate structural features and a multitude of biological functions. It is attractive to recreate these structures in the laboratory, as this allows mimicking and studying the properties of biomembranes and their constituents, and to specifically exploit the intrinsic two-dimensional fluidity. Even though diverse strategies for membrane fabrication have been reported, the development of related applications and technologies has been hindered by the unavailability of both versatile and simple methods. Here we report a rapid prototyping technology for two-dimensional fluidic devices, based on in-situ generated circuits of phospholipid films. In this “lab on a molecularly thin membrane”, various chemical and physical operations, such as writing, erasing, functionalization, and molecular transport, can be applied to user-defined regions of a membrane circuit. This concept is an enabling technology for research on molecular membranes and their technological use. PMID:24067786

Determining DfT Hardware by VHDL-AMS Fault Simulation for Biological Micro-Electronic Fluidic Arrays

NARCIS (Netherlands)

Kerkhoff, Hans G.; Zhang, X.; Liu, H.; Richardson, A.; Nouet, P.; Azais, F.

2005-01-01

The interest of microelectronic fluidic arrays for biomedical applications, like DNA determination, is rapidly increasing. In order to evaluate these systems in terms of required Design-for-Test structures, fault simulations in both fluidic and electronic domains are necessary. VHDL-AMS can be used

A computational analysis of the carbon-nanotube-based resonant-circuit sensors

International Nuclear Information System (INIS)

Grujicic, M.; Cao, G.; Roy, W.N.

2004-01-01

Available values for the molecular polarizability and the dipole moment and the computed adsorption energies to single walled carbon nanotubes (SWCNTs) for a couple of polar (NH 3 and CO) and several non-polar (He, Ar, N 2 and O 2 ) gases are used to help establish a correlation between the adsorbed gas-induced changes in the dielectric constant of the SWCNTs (the sensing material) and the resulting reduction in the resonant frequency of the resonant circuit-based chemical gas sensors. It is found that simple weighting methods which neglect the effect of changes in the electronic structure of the carbon nanotubes during adsorption are generally incapable of predicting correctly the changes in the effective dielectric constant of the carbon nanotubes. Conversely, the use of adsorption-induced changes in the band gap of the carbon nanotubes and a relationship between the band gap and the dielectric constant is found to be a promising approach for assessing the adsorption-induced changes in the effective dielectric constant of the carbon nanotubes and for establishment of their effect on the resonant frequency of resonator-based chemical gas sensors

MEMS- and NEMS-based complex adaptive smart devices and systems

Science.gov (United States)

Varadan, Vijay K.

2001-10-01

The microelectronics industry has seen explosive growth during the last thirty years. Extremely large markets for logic and memory devices have driven the development of new materials, and technologies for the fabrication of even more complex devices with feature sizes now down at the sub micron and nanometer level. Recent interest has arisen in employing these materials, tools and technologies for the fabrication of miniature sensors and actuators and their integration with electronic circuits to produce smart devices and systems. This effort offers the promise of: 1) increasing the performance and manufacturability of both sensors and actuators by exploiting new batch fabrication processes developed including micro stereo lithographic and micro molding techniques; 2) developing novel classes of materials and mechanical structures not possible previously, such as diamond like carbon, silicon carbide and carbon nanotubes, micro-turbines and micro-engines; 3) development of technologies for the system level and wafer level integration of micro components at the nanometer precision, such as self-assembly techniques and robotic manipulation; 4) development of control and communication systems for MEMS devices, such as optical and RF wireless, and power delivery systems, etc. A novel composite structure can be tailored by functionalizing carbon nanotubes and chemically bonding them with the polymer matrix e.g. block or graft copolymer, or even cross-linked copolymer, to impart exceptional structural, electronic and surface properties. Bio- and mechanical-MEMS devices derived from this hybrid composite provide a new avenue for future smart systems.

Performance optimization of MOS-like carbon nanotube-FETs with realistic source/drain contacts based on electrostatic doping

International Nuclear Information System (INIS)

Zhou Hailiang; Zhang Minxuan; Hao Yue

2010-01-01

Due to carrier band-to-band-tunneling (BTBT) through channel-source/drain contacts, conventional MOS-like Carbon Nanotube Field Effect Transistors (C-CNFETs) suffer from ambipolar conductance, which deteriorates the device performance greatly. In order to reduce such ambipolar behavior, a novel device structure based on electrostatic doping is proposed and all kinds of source/drain contacting conditions are considered in this paper. The non-equilibrium Green's function (NEGF) formalism based simulation results show that, with proper choice of tuning voltage, such electrostatic doping strategy can not only reduce the ambipolar conductance but also improve the sub-threshold performance, even with source/drain contacts being of Schottky type. And these are both quite desirable in circuit design to reduce the system power and improve the frequency as well. Further study reveals that the performance of the proposed design depends strongly on the choice of tuning voltage value, which should be paid much attention to obtain a proper trade-off between power and speed in application. (semiconductor devices)

Large-scale complementary macroelectronics using hybrid integration of carbon nanotubes and IGZO thin-film transistors.

Science.gov (United States)

Chen, Haitian; Cao, Yu; Zhang, Jialu; Zhou, Chongwu

2014-06-13

Carbon nanotubes and metal oxide semiconductors have emerged as important materials for p-type and n-type thin-film transistors, respectively; however, realizing sophisticated macroelectronics operating in complementary mode has been challenging due to the difficulty in making n-type carbon nanotube transistors and p-type metal oxide transistors. Here we report a hybrid integration of p-type carbon nanotube and n-type indium-gallium-zinc-oxide thin-film transistors to achieve large-scale (>1,000 transistors for 501-stage ring oscillators) complementary macroelectronic circuits on both rigid and flexible substrates. This approach of hybrid integration allows us to combine the strength of p-type carbon nanotube and n-type indium-gallium-zinc-oxide thin-film transistors, and offers high device yield and low device variation. Based on this approach, we report the successful demonstration of various logic gates (inverter, NAND and NOR gates), ring oscillators (from 51 stages to 501 stages) and dynamic logic circuits (dynamic inverter, NAND and NOR gates).

Carbon Nanotube-Based Ion Selective Sensors for Wearable Applications.

Science.gov (United States)

Roy, Soumyendu; David-Pur, Moshe; Hanein, Yael

2017-10-11

Wearable electronics offer new opportunities in a wide range of applications, especially sweat analysis using skin sensors. A fundamental challenge in these applications is the formation of sensitive and stable electrodes. In this article we report the development of a wearable sensor based on carbon nanotube (CNT) electrode arrays for sweat sensing. Solid-state ion selective electrodes (ISEs), sensitive to Na + ions, were prepared by drop coating plasticized poly(vinyl chloride) (PVC) doped with ionophore and ion exchanger on CNT electrodes. The ion selective membrane (ISM) filled the intertubular spaces of the highly porous CNT film and formed an attachment that was stronger than that achieved with flat Au, Pt, or carbon electrodes. Concentration of the ISM solution used influenced the attachment to the CNT film, the ISM surface morphology, and the overall performance of the sensor. Sensitivity of 56 ± 3 mV/decade to Na + ions was achieved. Optimized solid-state reference electrodes (REs), suitable for wearable applications, were prepared by coating CNT electrodes with colloidal dispersion of Ag/AgCl, agarose hydrogel with 0.5 M NaCl, and a passivation layer of PVC doped with NaCl. The CNT-based REs had low sensitivity (-1.7 ± 1.2 mV/decade) toward the NaCl solution and high repeatability and were superior to bare Ag/AgCl, metals, carbon, and CNT films, reported previously as REs. CNT-based ISEs were calibrated against CNT-based REs, and the short-term stability of the system was tested. We demonstrate that CNT-based devices implemented on a flexible support are a very attractive platform for future wearable technology devices.

A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

Directory of Open Access Journals (Sweden)

Waris Obitayo

2012-01-01

Full Text Available The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

Preparation of TiO2-based nanotubes/nanoparticles composite thin film electrodes for their electron transport properties

International Nuclear Information System (INIS)

Zhao, Wanyu; Fu, Wuyou; Chen, Jingkuo; Li, Huayang; Bala, Hari; Wang, Xiaodong; Sun, Guang; Cao, Jianliang; Zhang, Zhanying

2015-01-01

The composite thin film electrodes were prepared with one-dimensional (1D) TiO 2 -B nanotubes (NTs) and zero-dimensional TiO 2 nanoparticles (NPs) based on different weight ratios. The electron transport properties of the NTs/NPs composite thin film electrodes applied for dye-sensitized solar cells had been investigated systematically. The results indicated that although the amount of dye adsorption decreased slightly, the devices with the NTs/NPs composite thin film electrodes could obtain higher open-circuit voltage and overall conversion efficiency compared to devices with pure TiO 2 NPs electrodes by rational tuning the weight ratio of TiO 2 -B NTs and TiO 2 NPs. When the weight ratio of TiO 2 -B NTs in the NTs/NPs composite thin film electrodes increased, the density of states and recombination rate decreased. The 1D structure of TiO 2 -B NTs can provide direct paths for electron transport, resulting in higher electron lifetime, electron diffusion coefficient and electron diffusion length. The composite thin film electrodes possess the merits of the rapid electron transport of TiO 2 -B NTs and the high surface area of TiO 2 NPs, which has great applied potential in the field of photovoltaic devices. - Highlights: • The composite thin film electrodes (CTFEs) were prepared with nanotubes and nanoparticles. • The CTFEs possess the rapid electron transport and high surface area. • The CTFEs exhibit lower recombination rate and longer electron life time. • The CTFEs have great applied potential in the field of photovoltaic devices

Gecko-Inspired Carbon Nanotube-Based Adhesives

Science.gov (United States)

Ge, Liehui; Sethi, Sunny; Goyal, Anubha; Ci, Lijie; Ajayan, Pulickel; Dhinojwala, Ali

2009-03-01

Nature has developed hierarchical hairy structure on the wall-climbing gecko's foot, consisting of microscopic hairs called setae, which further split into hundreds of smaller structures called spatulas. In the last five years, numerous attempts to mimic gecko foot-hair using polymer soft molding and photolithography methods have been reported. However, most of these polymer-based synthetic gecko hairs fall short of the clinging ability of geckos. Vertically aligned carbon nanotubes (CNT) have shown strong adhesion at nanometer scale. Here, we present our work on developing CNT-based macroscopic flexible tape mimicking the hierarchical structure found on gecko's foot. The synthetic gecko tape is made by transferring aligned CNT array onto flexible polymer tape. The unpatterned CNT-gecko tape can support a shear force stress similar to gecko foot (10 N/cm^2). The supported shear stress increase by a factor of four, when we use micro-patterned CNT patches (50 to 500 μm). We find that both setae (replicated by CNT bundles) and spatulas (individual CNT) are necessary to achieve large macroscopic shear adhesion. The carbon nanotube-based tape offers an excellent synthetic option as a dry conductive reversible adhesive in microelectronics, robotics, and space applications.

The characteristics of carbon nanotubes grown at low temperature for electronic device application

Energy Technology Data Exchange (ETDEWEB)

Park, Yong Seob [Department of Photoelectronics Information, Chosun College of Science and Technology, Gwangju (Korea, Republic of); Yi, Junsin [School of Information and Communications Engineering, Sungkyunkwan University, Suwon, 440–746 (Korea, Republic of); Lee, Jaehyeong, E-mail: jaehyeong@skku.edu [School of Information and Communications Engineering, Sungkyunkwan University, Suwon, 440–746 (Korea, Republic of)

2013-11-01

For the application of carbon nanotubes (CNTs) in flexible electronic devices, the CNTs were grown on Corning 1737 glass substrate by microwave plasma enhanced chemical vapor deposition (MPECVD) method. To deposit the catalyst layer, TiN buffer layer of 200 nm thickness and Ni catalyst layer of 60 nm were first deposited on the glass by r.f. magnetron sputtering method. The CH{sub 4} and H{sub 2} gases are used as the synthesis gas of CNTs and the working pressure was about 2.13 kPa, and the substrate bias was about − 200 V. The growth time was from 2 min to 5 min and the microwave power was about 800 W. The substrate temperature as the main parameter was changed from 400 °C to 550 °C. The structural properties of CNTs synthesized with the substrate temperature were investigated using Raman, field emission scanning electron microscopy, and transmission electron microscopy methods. The surface and electrical properties of CNTs grown by MPECVD method were studied by scanning probe microscopy and four-point probe methods. We obtained the multi-walled CNTs (MW-CNTs). Multi-walled CNTs were vertically grown on Ni/TiN/glass substrates below 500 °C without any glass deformations. As the substrate temperature was increased, the crystallinity of CNTs was improved. Ni catalyst was found at the tip of CNT by the TEM observation and the grown CNTs were found to have a multi-walled with bamboo like structure. - Highlights: • Synthesis of vertically aligned carbon nanotubes. • Effects of substrate temperature on carbon nanotubes properties. • Improvement of the crystallinity with increasing substrate temperature. • Reduction of sheet resistance with increasing substrate temperature.

Rotating carbon nanotube membrane filter for water desalination

Science.gov (United States)

Tu, Qingsong; Yang, Qiang; Wang, Hualin; Li, Shaofan

2016-01-01

We have designed a porous nanofluidic desalination device, a rotating carbon nanotube membrane filter (RCNT-MF), for the reverse osmosis desalination that can turn salt water into fresh water. The concept as well as design strategy of RCNT-MF is modeled, and demonstrated by using molecular dynamics simulation. It has been shown that the RCNT-MF device may significantly improve desalination efficiency by combining the centrifugal force propelled reverse osmosis process and the porous CNT-based fine scale selective separation technology. PMID:27188982

Hydrogen-bond acidic functionalized carbon nanotubes (CNTs) with covalently-bound hexafluoroisopropanol groups

Energy Technology Data Exchange (ETDEWEB)

Fifield, Leonard S.; Grate, Jay W.

2010-06-01

Fluorinated hydrogen-bond acidic groups are directly attached to the backbone of single walled carbon nanotubes (SWCNTs) without the introduction of intermediate electron donating surface groups. Hexafluoroalcohol functional groups are exceptionally strong hydrogen bond acids, and are added to the nanotube surface using the aryl diazonium approach to create hydrogen-bond acidic carbon nanotube (CNT) surfaces. These groups can promote strong hydrogen-bonding interactions with matrix materials in composites or with molecular species to be concentrated and sensed. In the latter case, this newly developed material is expected to find useful application in chemical sensors and in CNT-based preconcentrator devices for the detection of pesticides, chemical warfare agents and explosives.

Manufacturing of Porous Ceramic Preforms Based on Halloysite Nanotubes (Hnts

Directory of Open Access Journals (Sweden)

Kujawa M.

2016-06-01

Full Text Available The aim of this study was to determine the influence of manufacturing conditions on the structure and properties of porous halloysite preforms, which during pressure infiltration were soaked with a liquid alloy to obtain a metal matrix composite reinforced by ceramic, and also to find innovative possibilities for the application of mineral nanotubes obtained from halloysite. The method of manufacturing porous ceramic preforms (based on halloysite nanotubes as semi-finished products that are applicable to modern infiltrated metal matrix composites was shown. The ceramic preforms were manufactured by sintering of halloysite nanotubes (HNT, Natural Nano Company (USA, with the addition of pores and canals forming agent in the form of carbon fibres (Sigrafil C10 M250 UNS SGL Group, the Carbon Company. The resulting porous ceramic skeletons, suggest innovative application capabilities mineral nanotubes obtained from halloysite.

Photodetectors based on carbon nanotubes deposited by using a spray technique on semi-insulating gallium arsenide

Directory of Open Access Journals (Sweden)

Domenico Melisi

2014-11-01

Full Text Available In this paper, a spray technique is used to perform low temperature deposition of multi-wall carbon nanotubes on semi-insulating gallium arsenide in order to obtain photodectors. A dispersion of nanotube powder in non-polar 1,2-dichloroethane is used as starting material. The morphological properties of the deposited films has been analysed by means of electron microscopy, in scanning and transmission mode. Detectors with different layouts have been prepared and current–voltage characteristics have been recorded in the dark and under irradiation with light in the range from ultraviolet to near infrared. The device spectral efficiency obtained from the electrical characterization is finally reported and an improvement of the photodetector behavior due to the nanotubes is presented and discussed.

Role of the Material Electrodes on Resistive Behaviour of Carbon Nanotube-Based Gas Sensors for H2S Detection

Directory of Open Access Journals (Sweden)

M. Lucci

2012-01-01

Full Text Available Miniaturized gas-sensing devices that use single-walled carbon nanotubes as active material have been fabricated using two different electrode materials, namely, Au/Cr and NbN. The resistive sensors have been assembled aligning by dielectrophoresis the nanotube bundles between 40 μm spaced Au/Cr or NbN multifinger electrodes. The sensing devices have been tested for detection of the H2S gas, in the concentration range 10–100 ppm, using N2 as carrier gas. No resistance changes were detected using sensor fabricated with NbN electrodes, whereas the response of the sensor fabricated with Au/Cr electrodes was characterized by an increase of the resistance upon gas exposure. The main performances of this sensor are a detection limit for H2S of 10 ppm and a recovery time of few minutes. The present study suggests that the mechanism involved in H2S gas detection is not a direct charge transfer between molecules and nanotubes. The hypothesis is that detection occurs through passivation of the Au surfaces by H2S molecules and modification of the contact resistance at the Au/nanotube interface.

Quantum size effect and thermal stability of carbon-nanotube-based quantum dot

International Nuclear Information System (INIS)

Huang, N.Y.; Peng, J.; Liang, S.D.; Li, Z.B.; Xu, N.S.

2004-01-01

Full text: Based on semi-experience quantum chemical calculation, we have investigated the quantum size effect and thermal stability of open-end carbon nanotube (5, 5) quantum dots of 20 to 400 atoms. It was found that there is a gap in the energy band of all carbon nanotube (5, 5) quantum dots although a (5, 5) carbon nanotube is metallic. The energy gap of quantum dots is much dependent of the number of atoms in a dot, as a result of the quantization rules imposed by the finite scales in both radial and axial directions of a carbon nanotube quantum dot. Also, the heat of formation of carbon nanotube quantum dots is dependent of the size of a quantum dot. (author)

Transport Phenomena in Nanowires, Nanotubes, and Other Low-Dimensional Systems

KAUST Repository

Montes, Enrique

2017-01-01

bonding. The current-voltage characteristics of nanotubes connected to Au electrodes is used to evaluate the change in resistivity upon adsorption. The observed selectivity and sensitivity properties make blue P nanotubes superior gas sensors for a wide range of applications. Using black P and blue P nanoribbons, we configure field effect transistors with atomically perfect junctions by using armchair nanoribbons as semiconducting channel and zigzag nanoribbons as metallic leads. We characterize the devices and observe a performance superior to Si-based devices, with on/off ratio of ~ 103, low subthreshold swing of ~ 60 mV/decade, and high transconductance of ~ 104 S/m.

Structure reconstruction of TiO2-based multi-wall nanotubes: first-principles calculations.

Science.gov (United States)

Bandura, A V; Evarestov, R A; Lukyanov, S I

2014-07-28

A new method of theoretical modelling of polyhedral single-walled nanotubes based on the consolidation of walls in the rolled-up multi-walled nanotubes is proposed. Molecular mechanics and ab initio quantum mechanics methods are applied to investigate the merging of walls in nanotubes constructed from the different phases of titania. The combination of two methods allows us to simulate the structures which are difficult to find only by ab initio calculations. For nanotube folding we have used (1) the 3-plane fluorite TiO2 layer; (2) the anatase (101) 6-plane layer; (3) the rutile (110) 6-plane layer; and (4) the 6-plane layer with lepidocrocite morphology. The symmetry of the resulting single-walled nanotubes is significantly lower than the symmetry of initial coaxial cylindrical double- or triple-walled nanotubes. These merged nanotubes acquire higher stability in comparison with the initial multi-walled nanotubes. The wall thickness of the merged nanotubes exceeds 1 nm and approaches the corresponding parameter of the experimental patterns. The present investigation demonstrates that the merged nanotubes can integrate the two different crystalline phases in one and the same wall structure.

The effect of dry shear aligning of nanotube thin films on the photovoltaic performance of carbon nanotube-silicon solar cells.

Science.gov (United States)

Stolz, Benedikt W; Tune, Daniel D; Flavel, Benjamin S

2016-01-01

Recent results in the field of carbon nanotube-silicon solar cells have suggested that the best performance is obtained when the nanotube film provides good coverage of the silicon surface and when the nanotubes in the film are aligned parallel to the surface. The recently developed process of dry shear aligning - in which shear force is applied to the surface of carbon nanotube thin films in the dry state, has been shown to yield nanotube films that are very flat and in which the surface nanotubes are very well aligned in the direction of shear. It is thus reasonable to expect that nanotube films subjected to dry shear aligning should outperform otherwise identical films formed by other processes. In this work, the fabrication and characterisation of carbon nanotube-silicon solar cells using such films is reported, and the photovoltaic performance of devices produced with and without dry shear aligning is compared.

Single walled carbon nanotubes functionally adsorbed to biopolymers for use as chemical sensors

Science.gov (United States)

Johnson, Jr., Alan T.; Gelperin, Alan [Princeton, NJ; Staii, Cristian [Madison, WI

2011-07-12

Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

Radiation-Hard Complementary Integrated Circuits Based on Semiconducting Single-Walled Carbon Nanotubes.

Science.gov (United States)

McMorrow, Julian J; Cress, Cory D; Gaviria Rojas, William A; Geier, Michael L; Marks, Tobin J; Hersam, Mark C

2017-03-28

Increasingly complex demonstrations of integrated circuit elements based on semiconducting single-walled carbon nanotubes (SWCNTs) mark the maturation of this technology for use in next-generation electronics. In particular, organic materials have recently been leveraged as dopant and encapsulation layers to enable stable SWCNT-based rail-to-rail, low-power complementary metal-oxide-semiconductor (CMOS) logic circuits. To explore the limits of this technology in extreme environments, here we study total ionizing dose (TID) effects in enhancement-mode SWCNT-CMOS inverters that employ organic doping and encapsulation layers. Details of the evolution of the device transport properties are revealed by in situ and in operando measurements, identifying n-type transistors as the more TID-sensitive component of the CMOS system with over an order of magnitude larger degradation of the static power dissipation. To further improve device stability, radiation-hardening approaches are explored, resulting in the observation that SWNCT-CMOS circuits are TID-hard under dynamic bias operation. Overall, this work reveals conditions under which SWCNTs can be employed for radiation-hard integrated circuits, thus presenting significant potential for next-generation satellite and space applications.

Indium telluride nanotubes: Solvothermal synthesis, growth mechanism, and properties

Energy Technology Data Exchange (ETDEWEB)

Zhou, Liyan [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Yan, Shancheng, E-mail: yansc@njupt.edu.cn [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); School of Geography and Biological Information, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China); Lu, Tao; Shi, Yi; Wang, Jianyu [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Yang, Fan [School of Geography and Biological Information, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China)

2014-03-15

A convenient solvothermal approach was applied for the first time to synthesize In{sub 2}Te{sub 3} nanotubes. The morphology of the resultant nanotubes was studied by scanning electron microscopy and transmission electron microscopy. Nanotubes with a relatively uniform diameter of around 500 nm, tube wall thickness of 50–100 nm, and average length of tens of microns were obtained. X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy were used to study the crystal structures, composition, and optical properties of the products. To understand the growth mechanism of the In{sub 2}Te{sub 3} nanotubes, we studied the influences of temperature, reaction time, and polyvinylpyrrolidone (PVP) and ethylene diamine (EDA) dosages on the final products. Based on the experimental results, a possible growth mechanism of In{sub 2}Te{sub 3} nanotubes was proposed. In this mechanism, TeO{sub 3}{sup −2} is first reduced to allow nucleation. Circumferential edges of these nucleated molecules attract further deposition, and nanotubes finally grow rapidly along the c-axis and relatively slowly along the circumferential direction. The surface area of the products was determined by BET and found to be 137.85 m{sup 2} g{sup −1}. This large surface area indicates that the nanotubes may be suitable for gas sensing and hydrogen storage applications. The nanotubes also showed broad light detection ranging from 300 nm to 1100 nm, which covers the UV–visible–NIR regions. Such excellent optical properties indicate that In{sub 2}Te{sub 3} nanotubes may enable significant advancements in new photodetection and photosensing applications. -- Graphical abstract: A convenient solvothermal approach was applied to synthesize In{sub 2}Te{sub 3} nanotubes, which has not been reported in the literature for our knowledge. Surface area of this material is 137.85 m{sup 2} g{sup −1} from the BET testing, and such a high value makes it probably suitable for gas sensing and

Fiber Optic Chemical Nanosensors Based on Engineered Single-Walled Carbon Nanotubes

Directory of Open Access Journals (Sweden)

M. Consales

2008-01-01

Full Text Available In this contribution, a review of the development of high-performance optochemical nanosensors based on the integration of carbon nanotubes with the optical fiber technology is presented. The paper first provide an overview of the amazing features of carbon nanotubes and their exploitation as highly adsorbent nanoscale materials for gas sensing applications. Successively, the attention is focused on the operating principle, fabrication, and characterization of fiber optic chemosensors in the Fabry-Perot type reflectometric configuration, realized by means of the deposition of a thin layer of single-walled carbon nanotubes (SWCNTs upon the distal end of standard silica optical fibers. This is followed by an extensive review of the excellent sensing capabilities of the realized SWCNTs-based chemical nanosensors against volatile organic compounds and other pollutants in different environments (air and water and operating conditions (room temperature and cryogenic temperatures. The experimental results reported here reveal that ppm and sub-ppm chemical detection limits, low response times, as well as fast and complete recovery of the sensor responses have been obtained in most of the investigated cases. This evidences the great potentialities of the proposed photonic nanosensors based on SWCNTs to be successfully employed for practical environmental monitoring applications both in liquid and vapor phase as well as for space. Furthermore, the use of novel SWCNTs-based composites as sensitive fiber coatings is proposed to enhance the sensing performance and to improve the adhesion of carbon nanotubes to the fiber surface. Finally, new advanced sensing configurations based on the use of hollow-core optical fibers coated and partially filled by carbon nanotubes are also presented.

Carbon nanotube plane fastener

Directory of Open Access Journals (Sweden)

Kaori Hirahara

2011-12-01

Full Text Available We report a feature of carbon nanotubes (CNTs that arises when the surfaces of two vertically-aligned CNT brushes are pressed together. Adhesion between the CNTs creates a plane fastener-like device. Observations from scanning electron microscopy and measurements of adhesion properties indicate a device-dependence on CNT density and shape near the tip region. Among other applications, such fasteners have the potential to attach small components onto micron-sized electronic devices.

An Evaluation of Power Fluidics Mixing and Pumping for Application in the Single Shell Tank (SST) Retrieval Program

International Nuclear Information System (INIS)

CRASS, D.W.

2001-01-01

This document is being released for information only. It provides an explanation of fluidics pumping and mixing technology and explores the feasibility of using fluidics technology for the retrieval of S102. It concludes that there are no obvious flaws that would prevent deploying the technology and recommends further development of fluidics technology as a retrieval option. The configuration described herein does not represent the basis for project definition

Impinging jets controlled by fluidic input signal

Czech Academy of Sciences Publication Activity Database

Tesař, Václav; Trávníček, Zdeněk; Peszyński, K.

2016-01-01

Roč. 249, October (2016), s. 85-92 ISSN 0924-4247 R&D Projects: GA ČR GA13-23046S; GA ČR GA14-08888S Institutional support: RVO:61388998 Keywords : fluidics * jets * impinging jets * coanda effect Subject RIV: BK - Fluid Dynamics Impact factor: 2.499, year: 2016 http://www.sciencedirect.com/science/article/pii/S0924424716303880

Growth of single-wall carbon nanotubes by chemical vapor deposition for electrical devices

OpenAIRE

Furer, Jürg

2006-01-01

Carbon emerges in di®erent forms. Diamond and graphite have been well known mate- rials for centuries. Moreover fullerenes and nanotubes were discovered only a few years ago. H. W. Kroto et al. depicted the fullerenes in 1985 [1]. A few years later, in 1991, S. Iijima described carbon nanotubes (CNTs) for the ¯rst time [2] (Figure 1.1). CNTs have a close relation to graphite, since a single-wall carbon nanotube is like a rolled-up graphite mono layer. However a nanotube has wi...

Single walled carbon nanotubes with functionally adsorbed biopolymers for use as chemical sensors

Science.gov (United States)

Johnson, Jr., Alan T

2013-12-17

Chemical field effect sensors comprising nanotube field effect devices having biopolymers such as single stranded DNA or RNA functionally adsorbed to the nanotubes are provided. Also included are arrays comprising the sensors and methods of using the devices to detect volatile compounds.

Flash μ-fluidics: a rapid prototyping method for fabricating microfluidic devices

KAUST Repository

Buttner, Ulrich

2016-08-01

Microfluidics has advanced in terms of design and structures; however, fabrication methods are time-consuming or expensive relative to facility costs and equipment needed. This work demonstrates a fast and economically viable 2D/3D maskless digital light-projection method based on a stereolithography process. Unlike other fabrication methods, one exposure step is used to form the whole device. Flash microfluidics is achieved by incorporating bonding and channel fabrication of complex structures in just 2.5 s to 4 s and by fabricating channel heights between 25 μm and 150 μm with photopolymer resin. The features of this fabrication technique, such as time and cost saving and easy fabrication, are used to build devices that are mostly needed in microfluidic/lab-on-chip systems. Due to the fast production method and low initial setup costs, the process could be used for point of care applications. © 2016 The Royal Society of Chemistry.

Flash μ-fluidics: a rapid prototyping method for fabricating microfluidic devices

KAUST Repository

Buttner, Ulrich; Sivashankar, Shilpa; Agambayev, Sumeyra; Mashraei, Yousof; Salama, Khaled N.

2016-01-01

Microfluidics has advanced in terms of design and structures; however, fabrication methods are time-consuming or expensive relative to facility costs and equipment needed. This work demonstrates a fast and economically viable 2D/3D maskless digital light-projection method based on a stereolithography process. Unlike other fabrication methods, one exposure step is used to form the whole device. Flash microfluidics is achieved by incorporating bonding and channel fabrication of complex structures in just 2.5 s to 4 s and by fabricating channel heights between 25 μm and 150 μm with photopolymer resin. The features of this fabrication technique, such as time and cost saving and easy fabrication, are used to build devices that are mostly needed in microfluidic/lab-on-chip systems. Due to the fast production method and low initial setup costs, the process could be used for point of care applications. © 2016 The Royal Society of Chemistry.

One step shift towards flexible supercapacitors based on carbon nanotubes - A review

Science.gov (United States)

Yar, A.; Dennis, J. O.; Mohamed, N. M.; Mumtaz, A.; Irshad, M. I.; Ahmad, F.

2014-10-01

Supercapacitors have emerged as prominent energy storage devices that offer high energy density compared to conventional capacitors and high power density which is not found in batteries. Carbon nanotubes (CNTs) because of their high surface area and tremendous electrical properties are used as electrode material for supercapacitors. In this review we focused on the factors like surface area, role of the electrolyte and techniques adopted to improve performance of CNTs based supercapacitors. The supercapacitors are widely tested in liquid electrolytes which are normally hazardous in nature, toxic, flammable and their leakage has safety concerns. This review also focuses on research which is replacing these unsafe electrolytes by solid electrolytes with the combination of low cost CNTs deposited flexible supports for supercapacitors.

One step shift towards flexible supercapacitors based on carbon nanotubes - A review

Energy Technology Data Exchange (ETDEWEB)

Yar, A., E-mail: asfandyarhargan@gmail.com, E-mail: johndennis@petronas.com.my, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: asad-032@yahoo.com, E-mail: imrancssp@gmail.com; Dennis, J. O., E-mail: asfandyarhargan@gmail.com, E-mail: johndennis@petronas.com.my, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: asad-032@yahoo.com, E-mail: imrancssp@gmail.com; Mohamed, N. M., E-mail: asfandyarhargan@gmail.com, E-mail: johndennis@petronas.com.my, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: asad-032@yahoo.com, E-mail: imrancssp@gmail.com; Mumtaz, A., E-mail: asfandyarhargan@gmail.com, E-mail: johndennis@petronas.com.my, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: asad-032@yahoo.com, E-mail: imrancssp@gmail.com; Irshad, M. I., E-mail: asfandyarhargan@gmail.com, E-mail: johndennis@petronas.com.my, E-mail: noranimuti-mohamed@petronas.com.my, E-mail: asad-032@yahoo.com, E-mail: imrancssp@gmail.com [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS (Malaysia); Ahmad, F., E-mail: ahmad-1234farooq@yahoo.com [Department of Electrical and Electronic Engineering, Universiti Teknologi PETRONAS (Malaysia)

2014-10-24

Supercapacitors have emerged as prominent energy storage devices that offer high energy density compared to conventional capacitors and high power density which is not found in batteries. Carbon nanotubes (CNTs) because of their high surface area and tremendous electrical properties are used as electrode material for supercapacitors. In this review we focused on the factors like surface area, role of the electrolyte and techniques adopted to improve performance of CNTs based supercapacitors. The supercapacitors are widely tested in liquid electrolytes which are normally hazardous in nature, toxic, flammable and their leakage has safety concerns. This review also focuses on research which is replacing these unsafe electrolytes by solid electrolytes with the combination of low cost CNTs deposited flexible supports for supercapacitors.

One step shift towards flexible supercapacitors based on carbon nanotubes - A review

International Nuclear Information System (INIS)

Yar, A.; Dennis, J. O.; Mohamed, N. M.; Mumtaz, A.; Irshad, M. I.; Ahmad, F.

2014-01-01

Supercapacitors have emerged as prominent energy storage devices that offer high energy density compared to conventional capacitors and high power density which is not found in batteries. Carbon nanotubes (CNTs) because of their high surface area and tremendous electrical properties are used as electrode material for supercapacitors. In this review we focused on the factors like surface area, role of the electrolyte and techniques adopted to improve performance of CNTs based supercapacitors. The supercapacitors are widely tested in liquid electrolytes which are normally hazardous in nature, toxic, flammable and their leakage has safety concerns. This review also focuses on research which is replacing these unsafe electrolytes by solid electrolytes with the combination of low cost CNTs deposited flexible supports for supercapacitors

Sensitive paper-based analytical device for fast colorimetric detection of nitrite with smartphone.

Science.gov (United States)

Zhang, Xiu-Xiu; Song, Yi-Zhen; Fang, Fang; Wu, Zhi-Yong

2018-04-01

On-site rapid monitoring of nitrite as an assessment indicator of the environment, food, and physiological systems has drawn extensive attention. Here, electrokinetic stacking (ES) was combined with colorimetric reaction on a paper-based device (PAD) to achieve colorless nitrite detection with smartphone. In this paper, nitrite was stacked on the paper fluidic channel as a narrow band by electrokinetic stacking. Then, Griess reagent was introduced to visualize the stacking band. Under optimal conditions, the sensitivity of nitrite was 160-fold increased within 5 min. A linear response in the range of 0.075 to 1.0 μg mL -1 (R 2  = 0.99) and a limit of detection (LOD) of 73 ng mL -1 (0.86 μM) were obtained. The LOD was 10 times lower than the reported PAD, and close to that achieved by a desktop spectrophotometer. The applicability was demonstrated by nitrite detection from saliva and water with good selectivity, adding 100 times more concentrated co-ions. High recovery (91.0~108.7%) and reasonable intra-day and inter-day reproducibility (RSD work shows that the sensitivity of colorless analyte detection-based colorimetric reaction can be effectively enhanced by integration of ES on a PAD. Graphical abstract Schematic of the experimental setups (left) and the corresponding images (right) of the actual portable device.

pH-Sensitive Hydrogel for Micro-Fluidic Valve

Directory of Open Access Journals (Sweden)

Zhengzhi Yang

2012-07-01

Full Text Available The deformation behavior of a pH-sensitive hydrogel micro-fluidic valve system is investigated using inhomogeneous gel deformation theory, in which the fluid-structure interaction (FSI of the gel solid and fluid flow in the pipe is considered. We use a finite element method with a well adopted hydrogel constitutive equation, which is coded in commercial software, ABAQUS, to simulate the hydrogel valve swelling deformation, while FLUENT is adopted to model the fluid flow in the pipe of the hydrogel valve system. The study demonstrates that FSI significantly affects the gel swelling deformed shapes, fluid flow pressure and velocity patterns. FSI has to be considered in the study on fluid flow regulated by hydrogel microfluidic valve. The study provides a more accurate and adoptable model for future design of new pH-sensitive hydrogel valves, and also gives a useful guideline for further studies on hydrogel fluidic applications.

Tunable Bandgap and Optical Properties of Black Phosphorene Nanotubes

Directory of Open Access Journals (Sweden)

Chunmei Li

2018-02-01

Full Text Available Black phosphorus (BP, a new two-dimensional material, has been the focus of scientists’ attention. BP nanotubes have potential in the field of optoelectronics due to their low-dimensional effects. In this work, the bending strain energy, electronic structure, and optical properties of BP nanotubes were investigated by using the first-principles method based on density functional theory. The results show that these properties are closely related to the rolling direction and radius of the BP nanotube. All the calculated BP nanotube properties show direct bandgaps, and the BP nanotubes with the same rolling direction express a monotone increasing trend in the value of bandgap with a decrease in radius, which is a stacking effect of the compression strain on the inner atoms and the tension strain on the outer atoms. The bending strain energy of the zigzag phosphorene nanotubes (zPNTs is higher than that of armchair phosphorene nanotubes (aPNT with the same radius of curvature due to the anisotropy of the BP’s structure. The imaginary part of the dielectric function, the absorption range, reflectivity, and the imaginary part of the refractive index of aPNTs have a wider range than those of zPNTs, with higher values overall. As a result, tunable BP nanotubes are suitable for optoelectronic devices, such as lasers and diodes, which function in the infrared and ultra-violet regions, and for solar cells and photocatalysis.

Micro-fluidic module for blood cell separation for gene expression radiobiological assays

International Nuclear Information System (INIS)

Brengues, Muriel; Gu, Jian; Zenhausern, Frederic

2015-01-01

Advances in molecular techniques have improved discovery of biomarkers associated with radiation exposure. Gene expression techniques have been demonstrated as effective tools for biodosimetry, and different assay platforms with different chemistries are now available. One of the main challenges is to integrate the sample preparation processing of these assays into micro-fluidic platforms to be fully automated for point-of-care medical countermeasures in the case of a radiological event. Most of these assays follow the same workflow processing that comprises first the collection of blood samples followed by cellular and molecular sample preparation. The sample preparation is based on the specific reagents of the assay system and depends also on the different subsets of cells population and the type of biomarkers of interest. In this article, the authors present a module for isolation of white blood cells from peripheral blood as a prerequisite for automation of gene expression assays on a micro-fluidic cartridge. For each sample condition, the gene expression platform can be adapted to suit the requirements of the selected assay chemistry (authors)

Copper-decorated carbon nanotubes-based composite electrodes for nonenzymatic detection of glucose

NARCIS (Netherlands)

Pop, A.; Manea, F.; Orha, C.; Motoc, S.; Llinoiu, E.; Vaszilcsin, N.; Schoonman, J.

2012-01-01

The aim of this study was to prepare three types of multiwall carbon nanotubes (CNT)-based composite electrodes and to modify their surface by copper electrodeposition for nonenzymatic oxidation and determination of glucose from aqueous solution. Copper-decorated multiwall carbon nanotubes composite

Continuous Growth of Vertically Aligned Carbon Nanotubes Forests

OpenAIRE

Guzman de Villoria, Roberto; Wardle, Brian L.

2011-01-01

Vertically aligned carbon nanotubes are one of the most promising materials due their numerous applications in flexible electronic devices, biosensors and multifunctional aircraft materials, among others. However, the costly production of aligned carbon nanotubes, generally in a batch process, prevents their commercial use. For the first time, a controlled process to grow aligned carbon nanotubes in a continuous manner is presented. Uniform growth is achieved using 2D and 3D substrates. A sig...

Electrochemical Capacitors Based on Aligned Carbon Nanotubes Directly Synthesized on Tantalum Substrates

International Nuclear Information System (INIS)

Kim, Byung Woo; Chung, Hae Geun; Kim, Woong; Min, Byoung Koun; Kim, Hong Gon

2010-01-01

We demonstrate that vertically aligned carbon nanotubes can be synthesized directly on tantalum substrate via waterassisted chemical vapor deposition and evaluate their properties as electrochemical capacitors. The mean diameter of the carbon nanotubes was 7.1 ± 1.5 nm, and 70% of them had double walls. The intensity ratio of G-band to D-band in Raman spectra was as high as 5, indicating good quality of the carbon nanotubes. Owing to the alignment and low equivalent series resistance, the carbon nanotube based supercapacitors showed good rate performance. Rectangular shape of cyclic voltammogram was maintained even at the scan rate of > 1 V/s in 1 M sulfuric acid aqueous solution. Specific capacitance was well-retained (∼94%) even when the discharging current density dramatically increased up to 145 A/g. Consequently, specific power as high as 60 kW/kg was obtained from as-grown carbon nanotubes in aqueous solution. Maximum specific energy of ∼20 Wh/kg was obtained when carbon nanotubes were electrochemically oxidized and operated in organic solution. Demonstration of direct synthesis of carbon nanotubes on tantalum current collectors and their applications as supercapacitors could be an invaluable basis for fabrication of high performance carbon nanotube supercapacitors

A carbon nanotube immunosensor for Salmonella

Science.gov (United States)

Lerner, Mitchell B.; Goldsmith, Brett R.; McMillon, Ronald; Dailey, Jennifer; Pillai, Shreekumar; Singh, Shree R.; Johnson, A. T. Charlie

2011-12-01

Antibody-functionalized carbon nanotube devices have been suggested for use as bacterial detectors for monitoring of food purity in transit from the farm to the kitchen. Here we report progress towards that goal by demonstrating specific detection of Salmonella in complex nutrient broth solutions using nanotube transistors functionalized with covalently-bound anti-Salmonella antibodies. The small size of the active device region makes them compatible with integration in large-scale arrays. We find that the on-state current of the transistor is sensitive specifically to the Salmonella concentration and saturates at low concentration (Salmonella and other bacteria types, with no sign of saturation even at much larger concentrations (108 cfu/ml).

Fast cholesterol detection using flow injection microfluidic device with functionalized carbon nanotubes based electrochemical sensor.

Science.gov (United States)

Wisitsoraat, A; Sritongkham, P; Karuwan, C; Phokharatkul, D; Maturos, T; Tuantranont, A

2010-12-15

This work reports a new cholesterol detection scheme using functionalized carbon nanotube (CNT) electrode in a polydimethylsiloxane/glass based flow injection microfluidic chip. CNTs working, silver reference and platinum counter electrode layers were fabricated on the chip by sputtering and low temperature chemical vapor deposition methods. Cholesterol oxidase prepared in polyvinyl alcohol solution was immobilized on CNTs by in-channel flow technique. Cholesterol analysis based on flow injection chronoamperometric measurement was performed in 150-μm-wide and 150-μm-deep microchannels. Fast and sensitive real-time detection was achieved with high throughput of more than 60 samples per hour and small sample volume of 15 μl. The cholesterol sensor had a linear detection range between 50 and 400 mg/dl. In addition, low cross-sensitivities toward glucose, ascorbic acid, acetaminophen and uric acid were confirmed. The proposed system is promising for clinical diagnostics of cholesterol with high speed real-time detection capability, very low sample consumption, high sensitivity, low interference and good stability. Copyright © 2010 Elsevier B.V. All rights reserved.

Effects of Interfaces on Dynamics in Micro-Fluidic Devices: Slip-Boundaries’ Impact on Rotation Characteristics of Polar Liquid Film Motors

Science.gov (United States)

Jiang, Su-Rong; Liu, Zhong-Qiang; Amos Yinnon, Tamar; Kong, Xiang-Mu

2017-05-01

A new approach for exploring effects of interfaces on polar liquids is presented. Their impact on the polar liquid film motor (PLFM) - a novel micro-fluidic device - is studied. We account for the interface’s impact by modeling slip boundary effects on the PLFM’s electro-hydro-dynamical rotations. Our analytical results show as k={l}s/R increases (with {l}s denoting the slip length resulting from the interface’s impact on the film’s properties, k > -1 and R denoting the film’s radius): (a) PLFMs subsequently exhibit rotation characteristics under “negative-”, “no-”, “partial-” and “perfect-” slip boundary conditions; (b) The maximum value of the linear velocity of the steady rotating film increases linearly and its location approaches the film’s border; (c) The decay of the angular velocities’ dependency on the distance from the center of the film slows down, resulting in a macroscopic flow near the boundary. With our calculated rotation speed distributions consistent with the existing experimental ones, research aiming at fitting computed to measured distributions promises identifying the factors affecting {l}s, e.g., solid-fluid potential interactions and surface roughness. The consistency also is advantageous for optimizing PLFM’s applications as micro-washers, centrifuges, mixers in the lab-on-a-chip. Supported by National Natural Science Foundation of China under Grant Nos. 11302118, 11275112, and Natural Science Foundation of Shandong Province under Grant No. ZR2013AQ015

Cylindrical-shaped nanotube field effect transistor

KAUST Repository

Hussain, Muhammad Mustafa; Fahad, Hossain M.; Smith, Casey E.; Rojas, Jhonathan Prieto

2015-01-01

A cylindrical-shaped nanotube FET may be manufactured on silicon (Si) substrates as a ring etched into a gate stack and filled with semiconductor material. An inner gate electrode couples to a region of the gate stack inside the inner circumference of the ring. An outer gate electrode couples to a region of the gate stack outside the outer circumference of the ring. The multi-gate cylindrical-shaped nanotube FET operates in volume inversion for ring widths below 15 nanometers. The cylindrical-shaped nanotube FET demonstrates better short channel effect (SCE) mitigation and higher performance (I.sub.on/I.sub.off) than conventional transistor devices. The cylindrical-shaped nanotube FET may also be manufactured with higher yields and cheaper costs than conventional transistors.

Cylindrical-shaped nanotube field effect transistor

KAUST Repository

Hussain, Muhammad Mustafa

2015-12-29

A cylindrical-shaped nanotube FET may be manufactured on silicon (Si) substrates as a ring etched into a gate stack and filled with semiconductor material. An inner gate electrode couples to a region of the gate stack inside the inner circumference of the ring. An outer gate electrode couples to a region of the gate stack outside the outer circumference of the ring. The multi-gate cylindrical-shaped nanotube FET operates in volume inversion for ring widths below 15 nanometers. The cylindrical-shaped nanotube FET demonstrates better short channel effect (SCE) mitigation and higher performance (I.sub.on/I.sub.off) than conventional transistor devices. The cylindrical-shaped nanotube FET may also be manufactured with higher yields and cheaper costs than conventional transistors.

Current-induced changes of migration energy barriers in graphene and carbon nanotubes.

Science.gov (United States)

Obodo, J T; Rungger, I; Sanvito, S; Schwingenschlögl, U

2016-05-21

An electron current can move atoms in a nanoscale device with important consequences for the device operation and breakdown. We perform first principles calculations aimed at evaluating the possibility of changing the energy barriers for atom migration in carbon-based systems. In particular, we consider the migration of adatoms and defects in graphene and carbon nanotubes. Although the current-induced forces are large for both the systems, in graphene the force component along the migration path is small and therefore the barrier height is little affected by the current flow. In contrast, the same barrier is significantly reduced in carbon nanotubes as the current increases. Our work also provides a real-system numerical demonstration that current-induced forces within density functional theory are non-conservative.

A High-Voltage SOI CMOS Exciter Chip for a Programmable Fluidic Processor System.

Science.gov (United States)

Current, K W; Yuk, K; McConaghy, C; Gascoyne, P R C; Schwartz, J A; Vykoukal, J V; Andrews, C

2007-06-01

A high-voltage (HV) integrated circuit has been demonstrated to transport fluidic droplet samples on programmable paths across the array of driving electrodes on its hydrophobically coated surface. This exciter chip is the engine for dielectrophoresis (DEP)-based micro-fluidic lab-on-a-chip systems, creating field excitations that inject and move fluidic droplets onto and about the manipulation surface. The architecture of this chip is expandable to arrays of N X N identical HV electrode driver circuits and electrodes. The exciter chip is programmable in several senses. The routes of multiple droplets may be set arbitrarily within the bounds of the electrode array. The electrode excitation waveform voltage amplitude, phase, and frequency may be adjusted based on the system configuration and the signal required to manipulate a particular fluid droplet composition. The voltage amplitude of the electrode excitation waveform can be set from the minimum logic level up to the maximum limit of the breakdown voltage of the fabrication technology. The frequency of the electrode excitation waveform can also be set independently of its voltage, up to a maximum depending upon the type of droplets that must be driven. The exciter chip can be coated and its oxide surface used as the droplet manipulation surface or it can be used with a top-mounted, enclosed fluidic chamber consisting of a variety of materials. The HV capability of the exciter chip allows the generated DEP forces to penetrate into the enclosed chamber region and an adjustable voltage amplitude can accommodate a variety of chamber floor thicknesses. This demonstration exciter chip has a 32 x 32 array of nominally 100 V electrode drivers that are individually programmable at each time point in the procedure to either of two phases: 0deg and 180deg with respect to the reference clock. For this demonstration chip, while operating the electrodes with a 100-V peak-to-peak periodic waveform, the maximum HV electrode

Optimization of photoelectrochemical water splitting performance on hierarchical TiO 2 nanotube arrays

KAUST Repository

Zhang, Z.

2012-02-10

In this paper, we show that by varying the voltages during two-step anodization the morphology of the hierarchical top-layer/bottom-tube TiO 2 (TiO 2 NTs) can be finely tuned between nanoring/nanotube, nanopore/nanotube, and nanohole-nanocave/nanotube morphologies. This allows us to optimize the photoelectrochemical (PEC) water splitting performance on the hierarchical TiO 2 NTs. The optimized photocurrent density and photoconversion efficiency in this study, occurring on the nanopore/nanotube TiO 2 NTs, were 1.59 mA cm -2 at 1.23 V vs. RHE and 0.84% respectively, which are the highest values ever reported on pristine TiO 2 materials under illumination of AM 1.5G. Our findings contribute to further improvement of the energy conversion efficiency of TiO 2-based devices.

Optimization of photoelectrochemical water splitting performance on hierarchical TiO 2 nanotube arrays

KAUST Repository

Zhang, Z.; Wang, Peng

2012-01-01

In this paper, we show that by varying the voltages during two-step anodization the morphology of the hierarchical top-layer/bottom-tube TiO 2 (TiO 2 NTs) can be finely tuned between nanoring/nanotube, nanopore/nanotube, and nanohole-nanocave/nanotube morphologies. This allows us to optimize the photoelectrochemical (PEC) water splitting performance on the hierarchical TiO 2 NTs. The optimized photocurrent density and photoconversion efficiency in this study, occurring on the nanopore/nanotube TiO 2 NTs, were 1.59 mA cm -2 at 1.23 V vs. RHE and 0.84% respectively, which are the highest values ever reported on pristine TiO 2 materials under illumination of AM 1.5G. Our findings contribute to further improvement of the energy conversion efficiency of TiO 2-based devices.

Sample handling in surface sensitive chemical and biological sensing: a practical review of basic fluidics and analyte transport.

Science.gov (United States)

Orgovan, Norbert; Patko, Daniel; Hos, Csaba; Kurunczi, Sándor; Szabó, Bálint; Ramsden, Jeremy J; Horvath, Robert

2014-09-01

This paper gives an overview of the advantages and associated caveats of the most common sample handling methods in surface-sensitive chemical and biological sensing. We summarize the basic theoretical and practical considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence of analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter, bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are all discussed. Typical application areas of particular arrangements are also highlighted, such as the monitoring of cellular adhesion, biomolecule adsorption-desorption and ligand-receptor affinity binding. Our work is a practical review in the sense that for every sample handling arrangement considered we present our own experimental data and critically review our experience with the given arrangement. In the experimental part we focus on sample handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study is equally applicable for other biosensing technologies in which an analyte in solution is captured at a surface and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisive role in determining the reliability of (bio)chemical sensing measurements, such as analyte transport to the sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handling of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspects closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) are also discussed, particularly with regard to their models used in biosensing. Copyright © 2014 Elsevier B.V. All rights reserved.

Ultra-Low-Power Smart Electronic Nose System Based on Three-Dimensional Tin Oxide Nanotube Arrays.

Science.gov (United States)

Chen, Jiaqi; Chen, Zhuo; Boussaid, Farid; Zhang, Daquan; Pan, Xiaofang; Zhao, Huijuan; Bermak, Amine; Tsui, Chi-Ying; Wang, Xinran; Fan, Zhiyong

2018-06-04

In this work, we present a high-performance smart electronic nose (E-nose) system consisting of a multiplexed tin oxide (SnO 2 ) nanotube sensor array, read-out circuit, wireless data transmission unit, mobile phone receiver, and data processing application (App). Using the designed nanotube sensor device structure in conjunction with multiple electrode materials, high-sensitivity gas detection and discrimination have been achieved at room temperature, enabling a 1000 times reduction of the sensor's power consumption as compared to a conventional device using thin film SnO 2 . The experimental results demonstrate that the developed E-nose can identify indoor target gases using a simple vector-matching gas recognition algorithm. In addition, the fabricated E-nose has achieved state-of-the-art sensitivity for H 2 and benzene detection at room temperature with metal oxide sensors. Such a smart E-nose system can address the imperative needs for distributed environmental monitoring in smart homes, smart buildings, and smart cities.

Composite electronic materials based on poly(3,4-propylenedioxythiophene) and highly charged poly(aryleneethynylene)-wrapped carbon nanotubes for supercapacitors.

Science.gov (United States)

Rosario-Canales, Mariem R; Deria, Pravas; Therien, Michael J; Santiago-Avilés, Jorge J

2012-01-01

Supercapacitor charge storage media were fabricated using the semiconducting polymer poly(3,4-propylenedioxythiophene) (PProDOT) and single-walled carbon nanotubes (SWNTs) that were helically wrapped with ionic, conjugated poly[2,6-{1,5-bis(3-propoxysulfonicacidsodiumsalt)}naphthylene]ethynylene (PNES). These PNES-wrapped SWNTs (PNES-SWNTs) enable efficient dispersion of individualized nanotubes in a wide range of organic solvents. PNES-SWNT film-modified Pt electrodes were prepared by drop casting PNES-SWNT suspensions in MeOH; high stability, first-generation PProDOT/PNES/SWNT composites were realized via electropolymerization of the ProDOT parent monomer (3,4-propylenedioxythiophene) in a 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/propylene carbonate solution at the PNES-SWNT-modified electrode. The electrochemical properties of PProDOT and PProDOT/PNES/SWNT single electrodes and devices were examined using cyclic voltammetric methods. The hybrid composites were found to enhance key supercapacitor figures of merit (charge capacity and capacitance) by approximately a factor of 2 relative to those determined for benchmark Type I devices that exploited a classic PProDOT-based electrode material. The charge/discharge stability of the supercapacitors was probed by repeated rounds of cyclic voltammetric evaluation at a minimum depth of discharge of 73%; these experiments demonstrated that the hybrid PProDOT/PNES/SWNT composites retained ~90% of their initial charge capacity after 21,000 charge/discharge cycles, contrasting analogous data obtained for PProDOT-based devices, which showed only 84% retention of their initial charge capacity. © 2011 American Chemical Society

Fabrication of Au nanoparticle/double-walled carbon nanotube film/TiO{sub 2} nanotube array/Ti heterojunctions with low resistance state for broadband photodetectors

Energy Technology Data Exchange (ETDEWEB)

Chen, Yan [School of Mathematics and Physics, Mianyang Teachers’ College (Mianyang Normal University), Mianyang 621000 (China); Zhang, Guowei; Dong, Zhanmin [Department of Physics and State Key Lab of Low-Dimensional Quantum Physics, Tsinghua University, Beijing100084 (China); Wei, Jinquan [Key Laboratory for Advanced Materials Processing Technology of Education Ministry, School of Materials Science and Engineering, Tsinghua University, Beijing100084 (China); Zhu, Jia-Lin [Department of Physics and State Key Lab of Low-Dimensional Quantum Physics, Tsinghua University, Beijing100084 (China); Sun, Jia-Lin, E-mail: jlsun@tsinghua.edu.cn [Department of Physics and State Key Lab of Low-Dimensional Quantum Physics, Tsinghua University, Beijing100084 (China); Collaborative Innovation Center of Quantum Matter, Beijing (China)

2017-03-01

A broadband photodetector based on Au nanoparticle/double-walled carbon nanotube film/TiO{sub 2} nanotube array /Ti multilayer heterojunction structures has been fabricated. A pre-electroforming process at a voltage bias of 35 V was used to switch the photodetector from a high resistance state to a low resistance state. At a voltage bias of 1 V under 532-nm laser illumination in air, the photoresponsivity of the device reached 15.41 mA W{sup −1}, which is enhanced by approximately 1.91 times when compared with that of device before deposition of Au nanoparticles. In addition, in a vacuum under a voltage bias of 1 V, the photoresponsivity of the device reached 23.29 mA W{sup −1} and 6.85 mA W{sup −1} at 532 nm and 1064 nm, respectively. The surface plasmon polaritons of the Au nanoparticles allowed extension of the sensitivity of the photosensitive regions into the mid-infrared range. The experimental results show that the device photoresponsivity reached 2.26 mA W{sup −1} at a voltage bias of 1 V under 10.6-µm laser illumination in air.

DFT investigation on the adsorption behavior of dimethyl and trimethyl amine molecules on borophene nanotube

Science.gov (United States)

Bhuvaneswari, R.; Chandiramouli, R.

2018-06-01

The electronic properties of borophene nanotube (BNT) are witnessed and the adsorption properties of dimethyl amine (DMA) and trimethyl amine (TMA) molecules on borophene nanotube are explored through non-equilibrium Green's function (NEGF) and density functional theory (DFT) method. The device density of states spectrum interprets the change in peak maxima, thus indicating the electron transition between DMA, TMA molecules and BNT base material. I-V characteristics strengthen the adsorption property of DMA and TMA on BNT by pointing out the variation in the current. The present work assures that borophene nanotube (BNT) can be employed as DMA and TMA sensor.

Single-Walled Carbon-Nanotubes-Based Organic Memory Structures

Directory of Open Access Journals (Sweden)

Sundes Fakher

2016-09-01

Full Text Available The electrical behaviour of organic memory structures, based on single-walled carbon-nanotubes (SWCNTs, metal–insulator–semiconductor (MIS and thin film transistor (TFT structures, using poly(methyl methacrylate (PMMA as the gate dielectric, are reported. The drain and source electrodes were fabricated by evaporating 50 nm gold, and the gate electrode was made from 50 nm-evaporated aluminium on a clean glass substrate. Thin films of SWCNTs, embedded within the insulating layer, were used as the floating gate. SWCNTs-based memory devices exhibited clear hysteresis in their electrical characteristics (capacitance–voltage (C–V for MIS structures, as well as output and transfer characteristics for transistors. Both structures were shown to produce reliable and large memory windows by virtue of high capacity and reduced charge leakage. The hysteresis in the output and transfer characteristics, the shifts in the threshold voltage of the transfer characteristics, and the flat-band voltage shift in the MIS structures were attributed to the charging and discharging of the SWCNTs floating gate. Under an appropriate gate bias (1 s pulses, the floating gate is charged and discharged, resulting in significant threshold voltage shifts. Pulses as low as 1 V resulted in clear write and erase states.

Template-based fabrication of nanowire-nanotube hybrid arrays

International Nuclear Information System (INIS)

Ye Zuxin; Liu Haidong; Schultz, Isabel; Wu Wenhao; Naugle, D G; Lyuksyutov, I

2008-01-01

The fabrication and structure characterization of ordered nanowire-nanotube hybrid arrays embedded in porous anodic aluminum oxide (AAO) membranes are reported. Arrays of TiO 2 nanotubes were first deposited into the pores of AAO membranes by a sol-gel technique. Co nanowires were then electrochemically deposited into the TiO 2 nanotubes to form the nanowire-nanotube hybrid arrays. Scanning electron microscopy and transmission electron microscopy measurements showed a high nanowire filling factor and a clean interface between the Co nanowire and the TiO 2 nanotube. Application of these hybrids to the fabrication of ordered nanowire arrays with highly controllable geometric parameters is discussed

Performance optimization of MOS-like carbon nanotube-FETs with realistic source/drain contacts based on electrostatic doping

Energy Technology Data Exchange (ETDEWEB)

Zhou Hailiang; Zhang Minxuan [School of Computer, National University of Defense Technology, Changsha 410073 (China); Hao Yue, E-mail: hlzhou@nudt.edu.cn [School of Microelectronics, Xidian University, Xi' an 710071 (China)

2010-12-15

Due to carrier band-to-band-tunneling (BTBT) through channel-source/drain contacts, conventional MOS-like Carbon Nanotube Field Effect Transistors (C-CNFETs) suffer from ambipolar conductance, which deteriorates the device performance greatly. In order to reduce such ambipolar behavior, a novel device structure based on electrostatic doping is proposed and all kinds of source/drain contacting conditions are considered in this paper. The non-equilibrium Green's function (NEGF) formalism based simulation results show that, with proper choice of tuning voltage, such electrostatic doping strategy can not only reduce the ambipolar conductance but also improve the sub-threshold performance, even with source/drain contacts being of Schottky type. And these are both quite desirable in circuit design to reduce the system power and improve the frequency as well. Further study reveals that the performance of the proposed design depends strongly on the choice of tuning voltage value, which should be paid much attention to obtain a proper trade-off between power and speed in application. (semiconductor devices)

Template-mediated synthesis and bio-functionalization of flexible lignin-based nanotubes and nanowires

Science.gov (United States)

Caicedo, Hector M.; Dempere, Luisa A.; Vermerris, Wilfred

2012-03-01

Limitations of cylindrical carbon nanotubes based on the buckminsterfullerene structure as delivery vehicles for therapeutic agents include their chemical inertness, sharp edges and toxicological concerns. As an alternative, we have developed lignin-based nanotubes synthesized in a sacrificial template of commercially available alumina membranes. Lignin is a complex phenolic plant cell wall polymer that is generated as a waste product from paper mills and biorefineries that process lignocellulosic biomass into fuels and chemicals. We covalently linked isolated lignin to the inner walls of activated alumina membranes and then added layers of dehydrogenation polymer onto this base layer via a peroxidase-catalyzed reaction. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 15 nm or nanowires with a nominal diameter of 200 nm. These novel nanotubes are flexible and can be bio-functionalized easily and specifically, as shown by in vitro assays with biotin and Concanavalin A. Together with their intrinsic optical properties, which can also be varied as a function of their chemical composition, these lignin-based nanotubes are expected to enable a variety of new applications including as delivery systems that can be easily localized and imaged after uptake by living cells.

Template-mediated synthesis and bio-functionalization of flexible lignin-based nanotubes and nanowires

International Nuclear Information System (INIS)

Caicedo, Hector M; Vermerris, Wilfred; Dempere, Luisa A

2012-01-01

Limitations of cylindrical carbon nanotubes based on the buckminsterfullerene structure as delivery vehicles for therapeutic agents include their chemical inertness, sharp edges and toxicological concerns. As an alternative, we have developed lignin-based nanotubes synthesized in a sacrificial template of commercially available alumina membranes. Lignin is a complex phenolic plant cell wall polymer that is generated as a waste product from paper mills and biorefineries that process lignocellulosic biomass into fuels and chemicals. We covalently linked isolated lignin to the inner walls of activated alumina membranes and then added layers of dehydrogenation polymer onto this base layer via a peroxidase-catalyzed reaction. By using phenolic monomers displaying different reactivities, we were able to change the thickness of the polymer layer deposited within the pores, resulting in the synthesis of nanotubes with a wall thickness of approximately 15 nm or nanowires with a nominal diameter of 200 nm. These novel nanotubes are flexible and can be bio-functionalized easily and specifically, as shown by in vitro assays with biotin and Concanavalin A. Together with their intrinsic optical properties, which can also be varied as a function of their chemical composition, these lignin-based nanotubes are expected to enable a variety of new applications including as delivery systems that can be easily localized and imaged after uptake by living cells. (paper)

Filtering Water by Use of Ultrasonically Vibrated Nanotubes

Science.gov (United States)

Gavalas, Lillian Susan

2009-01-01

Devices that could be characterized as acoustically driven molecular sieves have been proposed for filtering water to remove all biological contaminants and all molecules larger than water molecules. Originally intended for purifying wastewater for reuse aboard spacecraft, these devices could also be attractive for use on Earth in numerous settings in which there are requirements to obtain potable, medical-grade, or otherwise pure water from contaminated water supplies. These devices could also serve as efficient means of removing some or all water from chemical products . for example, they might be useful as adjuncts or substitutes for stills in the removal of water from alcohols and alcoholic beverages. These devices may be constructed using various materials, such as ceramics, metallics, or polymers, depending on end-use requirements. A representative device of this type (see figure) would include a polymeric disk, about 1 mm in diameter and between 1 and 40 microns thick, within which would be embedded single-wall carbon nanotubes aligned along the thickness axis. The polymeric disk would be part of a unitary polymeric ring assembly. An acoustic transducer in the form of a piezoelectric-film-and-electrode subassembly - typically 9 microns thick and made of poly(vinylidene fluoride) coated with copper 150 nm thick -. would be affixed to the outside of the outer polymeric ring by means of an electrically nonconductive epoxy. The nanotubes would be chosen to have diameters between about 8 and about 13.5 A because water molecules could fit into the nanotubes, but larger molecules could not. Water to be purified would be placed in contact with one face (typically, the upper face) of the filter disk. The surface tension of water is low enough that water molecules should enter and travel along the nanotubes, and computational simulations of molecular dynamics and experimental measurements have shown that the water molecules inside the nanotubes in this size range can

Centrifugal micro-fluidic platform for radiochemistry: Potentialities for the chemical analysis of nuclear spent fuels

International Nuclear Information System (INIS)

Bruchet, Anthony; Mariet, Clarisse; Taniga, Velan; Descroix, Stephanie; Malaquin, Laurent; Goutelard, Florence

2013-01-01

The use of a centrifugal micro-fluidic platform is for the first time reported as an alternative to classical chromatographic procedures for radiochemistry. The original design of the micro-fluidic platform has been thought to fasten and simplify the prototyping process with the use of a circular platform integrating four rectangular microchips made of thermoplastic. The microchips, dedicated to anion-exchange chromatographic separations, integrate a localized monolithic stationary phase as well as injection and collection reservoirs. The results presented here were obtained with a simplified simulated nuclear spent fuel sample composed of non-radioactive isotopes of Europium and Uranium, in proportion usually found for uranium oxide nuclear spent fuel. While keeping the analytical results consistent with the conventional procedure (extraction yield for Europium of ∼97%), the use of the centrifugal micro-fluidic platform allowed to reduce the volume of liquid needed by a factor of ∼250. Thanks to their unique 'easy-to-use' features, centrifugal micro-fluidic platforms are potential successful candidates for the down-scaling of chromatographic separation of radioactive samples (automation, multiplexing, easy integration in glove-boxes environment and low cost of maintenance). (authors)

Radio frequency and linearity performance of transistors using high-purity semiconducting carbon nanotubes.

Science.gov (United States)

Wang, Chuan; Badmaev, Alexander; Jooyaie, Alborz; Bao, Mingqiang; Wang, Kang L; Galatsis, Kosmas; Zhou, Chongwu

2011-05-24

This paper reports the radio frequency (RF) and linearity performance of transistors using high-purity semiconducting carbon nanotubes. High-density, uniform semiconducting nanotube networks are deposited at wafer scale using our APTES-assisted nanotube deposition technique, and RF transistors with channel lengths down to 500 nm are fabricated. We report on transistors exhibiting a cutoff frequency (f(t)) of 5 GHz and with maximum oscillation frequency (f(max)) of 1.5 GHz. Besides the cutoff frequency, the other important figure of merit for the RF transistors is the device linearity. For the first time, we report carbon nanotube RF transistor linearity metrics up to 1 GHz. Without the use of active probes to provide the high impedance termination, the measurement bandwidth is therefore not limited, and the linearity measurements can be conducted at the frequencies where the transistors are intended to be operating. We conclude that semiconducting nanotube-based transistors are potentially promising building blocks for highly linear RF electronics and circuit applications.

One-dimensional BiFeO{sub 3} nanotubes: Preparation, characterization, improved magnetic behaviors, and prospects

Energy Technology Data Exchange (ETDEWEB)

Wu, Lei [Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000 (China); School of Resources and Materials, Northeastern University at Qinhuangdao, Qinhuangdao 066004 (China); Sui, Wenbo; Dong, Chunhui; Zhang, Chao [Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000 (China); Jiang, Changjun, E-mail: 779322052@qq.com [Key Laboratory for Magnetism and Magnetic Materials of MOE, Lanzhou University, Lanzhou 730000 (China)

2016-10-30

Highlights: • We present a fabrication method of one-dimensional BFO nanotubes prepared using a sol–gel-based electrospinning process followed by thermal treatment. • By compared with BiFeO{sub 3} bulks, enhanced room temperature ferromagnetism has been successfully realized in BFO nanotubes. • The impacts of processing temperature on the final microscopic structure and component are characterized in detail. • The existence of plentiful oxygen vacancies will play a key role in terms of enhanced ferromagnetism. - Abstract: With the progress of science and technology, the growing demands for practical applications make low-dimensional multiferroics more appealing in areas such as chemical and bio-sensors, nanoelectronic, high-density data storage devices. One-dimensional BiFeO{sub 3} nanotubes were successfully synthesized by sol–gel-based electrospinning process. The images of scanning electron microscopy and transmission electron microscopy collectively demonstrate that BiFeO{sub 3} nanotubes with long slender structure and virtually uniform diameter of approximately 100 nm were observed at 500 °C annealing temperature. By compared with BiFeO{sub 3} bulks observed at 800 °C annealing temperature, enhanced room temperature ferromagnetism was successfully realized in BiFeO{sub 3} nanotubes at room temperature. The results of electron spin resonance measurement further confirm that ferromagnetic resonances were detected in BiFeO{sub 3} nanotubes at different temperature. X-ray photoelectron spectroscopy study proves the existence of plentiful oxygen vacancies in BiFeO{sub 3} nanotubes, which will play a key role in terms of enhanced ferromagnetism. The results will contribute to expand the applications of BiFeO{sub 3} into the new field of spintronic devices and high-density data storage media.

Multifunctional smart composites with integrated carbon nanotube yarn and sheet

Science.gov (United States)

Chauhan, Devika; Hou, Guangfeng; Ng, Vianessa; Chaudhary, Sumeet; Paine, Michael; Moinuddin, Khwaja; Rabiee, Massoud; Cahay, Marc; Lalley, Nicholas; Shanov, Vesselin; Mast, David; Liu, Yijun; Yin, Zhangzhang; Song, Yi; Schulz, Mark

2017-04-01

Multifunctional smart composites (MSCs) are materials that combine the good electrical and thermal conductivity, high tensile and shear strength, good impact toughness, and high stiffness properties of metals; the light weight and corrosion resistance properties of composites; and the sensing or actuation properties of smart materials. The basic concept for MSCs was first conceived by Daniel Inman and others about 25 years ago. Current laminated carbon and glass fiber polymeric composite materials have high tensile strength and are light in weight, but they still lack good electrical and thermal conductivity, and they are sensitive to delamination. Carbon nanotube yarn and sheets are lightweight, electrically and thermally conductive materials that can be integrated into laminated composite materials to form MSCs. This paper describes the manufacturing of high quality carbon nanotube yarn and sheet used to form MSCs, and integrating the nanotube yarn and sheet into composites at low volume fractions. Various up and coming technical applications of MSCs are discussed including composite toughening for impact and delamination resistance; structural health monitoring; and structural power conduction. The global carbon nanotube overall market size is estimated to grow from 2 Billion in 2015 to 5 Billion by 2020 at a CAGR of 20%. Nanotube yarn and sheet products are predicted to be used in aircraft, wind machines, automobiles, electric machines, textiles, acoustic attenuators, light absorption, electrical wire, sporting equipment, tires, athletic apparel, thermoelectric devices, biomedical devices, lightweight transformers, and electromagnets. In the future, due to the high maximum current density of nanotube conductors, nanotube electromagnetic devices may also become competitive with traditional smart materials in terms of power density.

Transparent conducting oxide nanotubes

Science.gov (United States)

Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Nagpal, Prashant

2014-09-01

Thin film or porous membranes made of hollow, transparent, conducting oxide (TCO) nanotubes, with high chemical stability, functionalized surfaces and large surface areas, can provide an excellent platform for a wide variety of nanostructured photovoltaic, photodetector, photoelectrochemical and photocatalytic devices. While large-bandgap oxide semiconductors offer transparency for incident light (below their nominal bandgap), their low carrier concentration and poor conductivity makes them unsuitable for charge conduction. Moreover, materials with high conductivity have nominally low bandgaps and hence poor light transmittance. Here, we demonstrate thin films and membranes made from TiO2 nanotubes heavily-doped with shallow Niobium (Nb) donors (up to 10%, without phase segregation), using a modified electrochemical anodization process, to fabricate transparent conducting hollow nanotubes. Temperature dependent current-voltage characteristics revealed that TiO2 TCO nanotubes, doped with 10% Nb, show metal-like behavior with resistivity decreasing from 6.5 × 10-4 Ωcm at T = 300 K (compared to 6.5 × 10-1 Ωcm for nominally undoped nanotubes) to 2.2 × 10-4 Ωcm at T = 20 K. Optical properties, studied by reflectance measurements, showed light transmittance up to 90%, within wavelength range 400 nm-1000 nm. Nb doping also improves the field emission properties of TCO nanotubes demonstrating an order of magnitude increase in field-emitter current, compared to undoped samples.

Carbon nanotube forests: a non-stick workbench for nanomanipulation

International Nuclear Information System (INIS)

Gjerde, Kjetil; Kjelstrup-Hansen, Jakob; Clausen, Casper H; Teo, Kenneth B K; Milne, William I; Rubahn, Horst-Guenter; Boeggild, Peter

2006-01-01

The ubiquitous static friction (stiction) and adhesion forces comprise a major obstacle in the manipulation of matter at the nanoscale (Falvo et al 1999 Nature 397 236; Urbakh M et al 2004 Nature 430 525). In this work it is shown that a surface coated with vertically aligned carbon nanotubes-a nanotube forest-acts as an effective non-stick workbench for the manipulation of micro-objects and fibres/wires with one or more dimensions in the nano-range. These include organic nanofibres (Balzer and Rubahn 2001 Appl. Phys. Lett. 79 3860) and microsized latex beads, which adhere strongly even to a conventional low surface-energy material like Teflon. Although organic nanofibres are attractive as device components due to their chemical adaptability, adhesion forces nearly always rule out manipulation as a route to assembly of prototype devices based on such materials, because organic materials are soft and fragile, and tend to stick to any surface. We demonstrate here that the nanotube forest due to its roughness not only exhibits very low stiction and dynamic friction; it also acts as a springy and mechanically compliant surface, making it possible to lift up and manipulate delicate nanostructures such as organic nanofibres in ways not possible on planar, rigid surfaces

Functionalized carbon nanotube doping of P3HT:PCBM photovoltaic devices for enhancing short circuit current and efficiency

Directory of Open Access Journals (Sweden)

Rohit Bhatia

2017-03-01

Full Text Available We have successfully functionalized multiwalled carbon nanotubes (MWCNTs using nitrene approach employing the two aryl azides as a precursor for nitrene generation. The dispersion of functionalized MWCNTs has been enhanced in various organic solvents. These functionalized MWCNTs have been successfully doped in various concentrations in the bulk heterojunction (BHJ organic photovoltaic (OPV cells with a poly (3-hexyl thiophene (P3HT and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM photoactive blended layer. The incorporation of MWCNTs with aryl functional groups, in active the layer, results in enhanced performance with respect to a reference cell. The maximum power conversion efficiency of 1.86% is achieved with adduct I while in the case of adduct II it gets double to 2.0% in comparison with a reference cell. This improvement in the device performance is attributed to enhanced exciton dissociation and improved charge transport properties due to the formation of a nanotube percolation network in the photoactive composite layer.

Flexible symmetric supercapacitors based on vertical TiO2 and carbon nanotubes

Science.gov (United States)

Chien, C. J.; Chang, Pai-Chun; Lu, Jia G.

2010-03-01

Highly conducting and porous carbon nanotubes are widely used as electrodes in double-layer-effect supercapacitors. In this presentation, vertical TiO2 nanotube array is fabricated by anodization process and used as supercapacitor electrode utilizing its compact density, high surface area and porous structure. By spin coating carbon nanotube networks on vertical TiO2 nanotube array as electrodes with 1M H2SO4 electrolyte in between, the specific capacitance can be enhanced by 30% compared to using pure carbon nanotube network alone because of the combination of double layer effect and redox reaction from metal oxide materials. Based on cyclic voltammetry and galvanostatic charge-discharge measurements, this type of hybrid electrode has proven to be suitable for high performance supercapacitor application and maintain desirable cycling stability. The electrochemical impedance spectroscopy technique shows that the electrode has good electrical conductivity. Furthermore, we will discuss the prospect of extending this energy storage approach in flexible electronics.