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Insulator
Kinds of Insulator Terms modified by Insulator Selected AbstractsElectric-Field-Assisted Nanostructuring of a Mott InsulatorADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Vincent Dubost Abstract Here, the first experimental evidence for a strong electromechanical coupling in the Mott insulator GaTa4Se8 that allows highly reproducible nanoscaled writing by means of scanning tunneling microscopy (STM) is reported. The local electric field across the STM junction is observed to have a threshold value above which the clean (100) surface of GaTa4Se8 becomes mechanically instable: at voltage biases >1.1,V, the surface suddenly inflates and comes in contact with the STM tip, resulting in nanometer-sized craters. The formed pattern can be indestructibly "read" by STM at a lower voltage bias, thus allowing 5,Tdots inch,2 dense writing/reading at room temperature. The discovery of the electromechanical coupling in GaTa4Se8 might give new clues in the understanding of the electric pulse induced resistive switching recently observed in this stoichiometric Mott insulator. [source] Bacteriorhodopsin-Monolayer-Based Planar Metal,Insulator,Metal Junctions via Biomimetic Vesicle Fusion: Preparation, Characterization, and Bio-optoelectronic Characteristics,ADVANCED FUNCTIONAL MATERIALS, Issue 8 2007D. Jin Abstract A reliable and reproducible method for preparing bacteriorhodopsin (bR)-containing metal,biomolecule,monolayer-metal planar junctions via vesicle fusion tactics and soft deposition of Au top electrodes is reported. Optimum monolayer and junction preparations, including contact effects, are discussed. The electron-transport characteristics of bR-containing membranes are studied systematically by incorporating native bR or artificial bR pigments derived from synthetic retinal analogues, into single solid-supported lipid bilayers. Current,voltage (I,V) measurements at ambient conditions show that a single layer of such bR-containing artificial lipid bilayers pass current in solid electrode/bilayer/solid electrode structures. The current is passed only if retinal or its analogue is present in the protein. Furthermore, the preparations show photoconductivity as long as the retinal can isomerize following light absorption. Optical characterization suggests that the junction photocurrents might be associated with a photochemically induced M-like intermediate of bR. I,V measurements along with theoretical estimates reveal that electron transfer through the protein is over four orders of magnitude more efficient than what would be estimated for direct tunneling through 5,nm of water-free peptides. Our results furthermore suggest that the light-driven proton-pumping activity of the sandwiched solid-state bR monolayer contributes negligibly to the steady-state light currents that are observed, and that the orientation of bR does not significantly affect the observed I,V characteristics. [source] Photocurable Organic Gate Insulator for the Fabrication of High-Field Effect Mobility Organic Transistors by Low Temperature and Solution Processing,ADVANCED MATERIALS, Issue 18 2007T.-W. Lee A new organic gate insulator in OTFT devices, which satisfies the requirements for the fabrication of a practical TFT array, such as a good chemical resistance, a low moisture uptake, a low temperature process, and a good film surface smoothness, is introduced. Since this gate insulator film is formed by photo-curing after spincasting on the top of the gate electrode, the process does not require high temperatures. [source] Insulator to metal transition induced by substitution in the nearly two-dimensional compound CuCr1,xVxS2PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 8 2006N. Tsujii The cover picture of this issue of physica status solidi (c) has been taken from the article [1]. [source] Alkali Metal Doped Organic Molecules on Insulators: Charge Impact on the Optical PropertiesADVANCED MATERIALS, Issue 36 2010Thomas Dienel Doping-induced absorption changes of organic molecules on an insulating solid are reported. The charge transfer between alkali metal atoms and individual molecules on a surface leads to new electronic transitions identified with optical absorption spectroscopy. Progressive doping allows the discrimination of neutral, monoanionic and dianionic molecules in the solid state through examination of the spectra and rate equation modeling. [source] Muffin-Tin Orbital Wannier-Like Functions for Insulators and MetalsCHEMPHYSCHEM, Issue 9 2005Eva Zurek Abstract Herein, we outline a method that is able to generate truly minimal basis sets that accurately describe either a group of bands, a band, or even just the occupied part of a band. These basis sets are the so-called NMTOs, muffin-tin orbitals of order N. For an isolated set of bands, symmetrical orthonormalization of the NMTOs yields a set of Wannier functions that are atom-centered and localized by construction. They are not necessarily maximally localized, but may be transformed into those Wannier functions. For bands that overlap others, Wannier-like functions can be generated. It is shown that NMTOs give a chemical understanding of an extended system. In particular, orbitals for the , and , bands in an insulator, boron nitride, and a semimetal, graphite, will be considered. In addition, we illustrate that it is possible to obtain Wannier-like functions for only the occupied states in a metallic system by generating NMTOs for cesium. Finally, we visualize the pressure-induced s,d transition. [source] Bio-Inspired, Smart, Multiscale Interfacial Materials,ADVANCED MATERIALS, Issue 15 2008Fan Xia Abstract In this review a strategy for the design of bioinspired, smart, multiscale interfacial (BSMI) materials is presented and put into context with recent progress in the field of BSMI materials spanning natural to artificial to reversibly stimuli-sensitive interfaces. BSMI materials that respond to single/dual/multiple external stimuli, e.g., light, pH, electrical fields, and so on, can switch reversibly between two entirely opposite properties. This article utilizes hydrophobicity and hydrophilicity as an example to demonstrate the feasibility of the design strategy, which may also be extended to other properties, for example, conductor/insulator, p-type/n-type semiconductor, or ferromagnetism/anti-ferromagnetism, for the design of other BSMI materials in the future. [source] Analysis of regulatory elements of E-cadherin with reporter gene constructs in transgenic mouse embryosDEVELOPMENTAL DYNAMICS, Issue 2 2003Marc P. Stemmler Abstract Proper regulation of E-cadherin,mediated cell adhesion is important during early embryonic development and in organogenesis. In mice, E-cadherin is expressed from the fertilized egg onward and becomes down-regulated during gastrulation in mesoderm and its derivatives, but its expression is maintained in all epithelia. E-cadherin promoter analyses led to the identification of binding sites for two transcriptional repressors, Snail and SIP1, which are able to mediate down-regulation in vitro, but little is known about the regulatory elements that govern E-cadherin transcriptional activity in vivo. Here, we compared the developmentally regulated expression of a series of lacZ -reporter transgenes fused to different sequences of the murine E-cadherin gene between ,6 kb, including the promoter, and +16 kb, covering one third of intron 2. Four different segments with distinct regulatory properties were identified. The promoter fragment from +0.1 to ,1.5 kb remains inactive in most cases but occasionally induces ectopic expression in mesodermal tissues, although it contains binding sites for the repressors Snail and SIP1. This promoter fragment also lacks positive elements needed for the activation of transcription in ectoderm and endoderm. Sequences from ,1.5 to ,6 kb harbor regulatory elements for brain-specific expression and, in addition, insulator or silencer elements, because they are consistently inactive in the mesoderm. Only if sequences from +0.1 to +11 kb are combined with the promoter fragments is E-cadherin,specific transgene expression observed in endoderm and certain epithelia. Sequences between +11 and +16 kb contain cis -active elements that generally enhance transcription. Our analyses show that E-cadherin expression is governed by a complex interplay of multiple regulatory regions dispersed throughout large parts of the locus. Developmental Dynamics 227:238,245, 2003. © 2003 Wiley-Liss, Inc. [source] Bacteria concentration using a membrane type insulator-based dielectrophoresis in a plastic chipELECTROPHORESIS, Issue 18 2009Yoon-Kyoung Cho Abstract We report an insulator-based (or, electrodeless) dielectrophoresis utilizing microfabricated plastic membranes. The membranes with honeycomb-type pores have been fabricated by patterning the SU-8 layer on a substrate which was pretreated with self-assembled monolayer of octadecyltrichlorosilane for the easy release. The fabricated membrane was positioned between two electrodes and alternating current field was applied for the particle trap experiments. The particle could be trapped due to the dielectrophoresis force generated by the non-uniformities of the electric fields applied through the membranes with pores. Simulations using CFD-ACE+(CFD Research, Huntsville, Alabama) suggested that the dielectrophoresis force is stronger in the edge of the pores where the field gradient is highest. The bacteria could be captured on the near edge of the pores when the electric field was turned on and the trapped bacteria could be released when the field was turned off with the release efficiency of more than 93±7%. The maximal trapping efficiency of 66±7% was obtained under the electric fields (E=128,V/mm and f=300,kHz) when the dilute bacteria solution (Escherichia coli: 9.3×103,cell/mL, 0.5,mS/m) flowed with a flow rate of 100,,L/min. [source] Heat Transfer in Polypropylene-Based Foams Produced Using Different Foaming Processes,ADVANCED ENGINEERING MATERIALS, Issue 10 2009Marcelo Antunes This paper presents the characterization of the cellular structure and thermal conduction behaviour of polypropylene foams produced using different foaming processes, with the aim of selecting the best possible PP foam thermal insulator. Thermal conductivity results have shown that the global heat transfer behaviour is controlled by the relative density. For relative densities higher than 0.2, thermal conductivity differences were insignificant, the data being predicted by the mixture's rule and Russell's model. In the low density range, all of the proposed models underestimated the overall conductivity, the effect of the processing method being more significant, slight differences being observed between foams produced by extrusion and those produced by gas dissolution with higher cell sizes and anisotropies. Foams with finer cellular structures showed to be better insulating materials. [source] The Effects of Moisture in Low-Voltage Organic Field-Effect Transistors Gated with a Hydrous Solid ElectrolyteADVANCED FUNCTIONAL MATERIALS, Issue 16 2010Nikolai Kaihovirta Abstract The concept of using ion conducting membranes (50,150 ,m thick) for gating low-voltage (1 V) organic field-effect transistors (OFETs) is attractive due to its low-cost and large-area manufacturing capabilities. Furthermore, the membranes can be tailor-made to be ion conducting in any desired way or pattern. For the electrolyte gated OFETs in general, the key to low-voltage operation is the electrolyte "insulator" (the membrane) that provides a high effective capacitance due to ionic polarization within the insulator. Hydrous ion conducting membranes are easy to process and readily available. However, the role of the water in combination with the polymeric semiconductor has not yet been fully clarified. In this work electrical and optical techniques are utilized to carefully monitor the electrolyte/semiconductor interface in an ion conducting membrane based OFET. The main findings are that 1) moisture plays a major part in the transistor operation and careful control of both the ambient atmosphere and the potential differences between the electrodes are required for stable and consistent device behavior, 2) the obtained maximum effective capacitance (5 ,F cm,2) of the membrane suggests that the electric double layer is distributed over a broad region within the polyelectrolyte, and 3) electromodulation spectroscopy combined with current,voltage characteristics provide a method to determine the threshold gate voltage from an electrostatic field-effect doping to a region of (irreversible) electrochemical perturbation of the polymeric semiconductor. [source] The ,-to-, Transition in BiFeO3: A Powder Neutron Diffraction StudyADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Donna C. Arnold Abstract High-temperature powder neutron diffraction experiments are conducted around the reported ,,, phase transition (,930,°C) in BiFeO3. The results demonstrate that while a small volume contraction is observed at the transition temperature, consistent with an insulator,metal transition, both the ,- and ,-phase of BiFeO3 exhibit orthorhombic symmetry; i.e., no further increase of symmetry occurs during this transition. The ,-orthorhombic phase is observed to persist up to a temperature of approximately 950,°C before complete decomposition into Bi2Fe4O9 (and liquid Bi2O3), which subsequently begins to decompose at approximately 960,°C. [source] Electronic Contact Deposition onto Organic Molecular Monolayers: Can We Detect Metal Penetration?ADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Hagay Shpaisman Abstract Using a semiconductor as the substrate to a molecular organic layer, penetration of metal contacts can be clearly identified by the study of electronic charge transport through the layer. A series of monolayers of saturated hydrocarbon molecules with varying lengths is assembled on Si or GaAs and the junctions resulting after further electronic contact is made by liquid Hg, indirect metal evaporation, and a "ready-made" metal pad are measured. In contrast to tunneling characteristics, which are ambiguous regarding contact penetration, the semiconductor surface barrier is very sensitive to any direct contact with a metal. With the organic monolayer intact, a metal,insulator,semiconductor (MIS) structure results. If metal penetrated the monolayer, the junction behaves as a metal,semiconductor (MS) structure. By comparing a molecule-free interface (MS junction) with a molecularly modified one (presumably MIS), possible metal penetration is identified. The major indicators are the semiconductor electronic transport barrier height, extracted from the junction transport characteristics, and the photovoltage. The approach does not require a series of different monolayers and data analysis is quite straightforward, helping to identify non-invasive ways to make electronic contact to soft matter. [source] Effect of Contact Mode on the Electrical Transport and Field-Emission Performance of Individual Boron NanowiresADVANCED FUNCTIONAL MATERIALS, Issue 12 2010Fei Liu Abstract Vapor,liquid,solid processing of boron nanowires (BNWs) can be carried out either using a bottom-up or top-down growth mode, which results in different contact modes between the nanowire and the substrate. The contact mode may strongly affect the electrical transport and field-emission performance of the individual boron nanowires grown on a Si substrate. The electrical transport and field-emission characteristics of individual boron nanowires of different contact modes are investigated in situ using a scanning electron microscope. The contact barriers are very distinct for the different contact modes. Moreover, the transition from a "contact-limited" to a "bulk-limited" field-emission (FE) process is demonstrated in nanoemitters for the first time, and the proposed improved metal,insulator,vacuum (MIV) model may better illustrate the nonlinear behavior of the Fowler-Nordheim (FN) plots in these nanoscale systems. Individual BNWs with different contact modes have a discrepancy in their emission stability and vacuum breakdown characteristics though they have similar aspect ratios, which suggests that their electrical transport and field-emission performance are closely related to their contact mode. Boron nanowires grown in the base-up mode have better field-emission performances and are more beneficial than those grown in the top-down mode for various device applications. [source] Polymer Field-Effect Transistors Fabricated by the Sequential Gravure Printing of Polythiophene, Two Insulator Layers, and a Metal Ink GateADVANCED FUNCTIONAL MATERIALS, Issue 2 2010Monika M. Voigt Abstract The mass production technique of gravure contact printing is used to fabricate state-of-the art polymer field-effect transistors (FETs). Using plastic substrates with prepatterned indium tin oxide source and drain contacts as required for display applications, four different layers are sequentially gravure-printed: the semiconductor poly(3-hexylthiophene-2,5-diyl) (P3HT), two insulator layers, and an Ag gate. A crosslinkable insulator and an Ag ink are developed which are both printable and highly robust. Printing in ambient and using this bottom-contact/top-gate geometry, an on/off ratio of >104 and a mobility of 0.04,cm2 V,1 s,1 are achieved. This rivals the best top-gate polymer FETs fabricated with these materials. Printing using low concentration, low viscosity ink formulations, and different P3HT molecular weights is demonstrated. The printing speed of 40,m min,1 on a flexible polymer substrate demonstrates that very high-volume, reel-to-reel production of organic electronic devices is possible. [source] Insulator Polarization Mechanisms in Polyelectrolyte-Gated Organic Field-Effect TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 20 2009Oscar Larsson Abstract Electrolyte-gated organic field-effect transistors (OFETs) hold promise for robust printed electronics operating at low voltages. The polarization mechanism of thin solid electrolyte films, the gate insulator in such OFETs, is still unclear and appears to limit the transient current characteristics of the transistors. Here, the polarization response of a thin proton membrane, a poly(styrenesulfonic acid) film, is controlled by varying the relative humidity. The formation of the conducting transistor channel follows the polarization of the polyelectrolyte, such that the drain transient current characteristics versus the time are rationalized by three different polarization mechanisms: the dipolar relaxation at high frequencies, the ionic relaxation (migration) at intermediate frequencies, and the electric double-layer formation at the polyelectrolyte interfaces at low frequencies. The electric double layers of polyelectrolyte capacitors are formed in ,1,µs at humid conditions and an effective capacitance per area of 10,µF cm,2 is obtained at 1,MHz, thus suggesting that this class of OFETs might operate at up to 1,MHz at 1,V. [source] Functional analysis of the sea urchin-derived arylsulfatase (Ars)-element in mammalian cellsGENES TO CELLS, Issue 9 2006Satoshi Watanabe An insulator is a DNA sequence that has both enhancer-blocking activity, through its ability to modify the influence of neighboring cis -acting elements, and a barrier function that protects a transgene from being silenced by surrounding chromatin. Previously, we isolated and characterized a 582-bp-long element from the sea urchin arylsulfatase gene (Ars). This Ars -element was effective in sea urchin and Drosophila embryos and in plant cells. To investigate Ars -element activity in mammalian cells, we placed the element between the cytomegalovirus enhancer and a luciferase (luc) expression cassette. In contrast to controls lacking the Ars -element, NIH3T3 and 293T cells transfected with the element-containing construct displayed reduced luciferase activities. The Ars -element therefore acts as an enhancer-blocking element in mammalian cells. We assessed the barrier activity of the Ars -element using vectors in which a luc expression cassette was placed between two elements. Transfection experiments demonstrated that luc activity in these vectors was approximately ten-fold higher than in vectors lacking elements. Luc activities were well maintained even after 12 weeks in culture. Our observations demonstrate that the Ars -element has also a barrier activity. These results indicated that the Ars -element act as an insulator in mammalian cells. [source] Electric-Field-Assisted Nanostructuring of a Mott InsulatorADVANCED FUNCTIONAL MATERIALS, Issue 17 2009Vincent Dubost Abstract Here, the first experimental evidence for a strong electromechanical coupling in the Mott insulator GaTa4Se8 that allows highly reproducible nanoscaled writing by means of scanning tunneling microscopy (STM) is reported. The local electric field across the STM junction is observed to have a threshold value above which the clean (100) surface of GaTa4Se8 becomes mechanically instable: at voltage biases >1.1,V, the surface suddenly inflates and comes in contact with the STM tip, resulting in nanometer-sized craters. The formed pattern can be indestructibly "read" by STM at a lower voltage bias, thus allowing 5,Tdots inch,2 dense writing/reading at room temperature. The discovery of the electromechanical coupling in GaTa4Se8 might give new clues in the understanding of the electric pulse induced resistive switching recently observed in this stoichiometric Mott insulator. [source] Talus Instability in a Recent Deglaciation Area and Its Relationship to Buried Ice and Snow Cover Evolution (Picacho Del Veleta, Sierra Nevada, Spain)GEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 2 2003Antonio Gómez The southernmost glacier in Europe formed during the Little Ice Age at the foot of the north wall of Picacho del Veleta (3 398 m) in Sierra Nevada, in the southeast region of the Iberian Peninsula (lat. 37,03,N, long. 3,22,W). The glacier gradually retreated during the last century, leaving a large talus slope at the base of the wall. The unconsolidated material covering the ice masses acted as a thermal insulator. Recent bottom temperature of snow (BTS) analyses and drillings indicate that the ice still exists within the talus. Evidence from field observations made during the period 1995,2001, revealed that large mass movements occurred during the driest summers (1998 and especially, 1999 and 2000) when the talus was snow free. These conditions suggest a direct relationship between talus stability and thermal insulation from the snow cover in areas where buried ice or decaying marginal permafrost exists. [source] Non-volatile Ferroelectric Poly(vinylidene fluoride- co -trifluoroethylene) Memory Based on a Single-Crystalline Tri-isopropylsilylethynyl Pentacene Field-Effect TransistorADVANCED FUNCTIONAL MATERIALS, Issue 10 2009Seok Ju Kang Abstract A new type of nonvolatile ferroelectric poly(vinylidene fluoride- co -trifluoroethylene) (P(VDF-TrFE)) memory based on an organic thin-film transistor (OTFT) with a single crystal of tri-isopropylsilylethynyl pentacene (TIPS-PEN) as the active layer is developed. A bottom-gate OTFT is fabricated with a thin P(VDF-TrFE) film gate insulator on which a one-dimensional ribbon-type TIPS-PEN single crystal, grown via a solvent-exchange method, is positioned between the Au source and drain electrodes. Post-thermal treatment optimizes the interface between the flat, single-crystalline ab plane of TIPS-PEN and the polycrystalline P(VDF-TrFE) surface with characteristic needle-like crystalline lamellae. As a consequence, the memory device exhibits a substantially stable source,drain current modulation with an ON/OFF ratio hysteresis greater than 103, which is superior to a ferroelectric P(VDF-TrFE) OTFT that has a vacuum-evaporated pentacene layer. Data retention longer than 5,×,104 s is additionally achieved in ambient conditions by incorporating an interlayer between the gate electrode and P(VDF-TrFE) thin film. The device is environmentally stable for more than 40 days without additional passivation. The deposition of a seed solution of TIPS-PEN on the chemically micropatterned surface allows fabrication arrays of TIPS-PEN single crystals that can be potentially useful for integrated arrays of ferroelectric polymeric TFT memory. [source] High-Density Carrier Accumulation in ZnO Field-Effect Transistors Gated by Electric Double Layers of Ionic LiquidsADVANCED FUNCTIONAL MATERIALS, Issue 7 2009Hongtao Yuan Abstract Very recently, electric-field-induced superconductivity in an insulator was realized by tuning charge carrier to a high density level (1,×,1014 cm,2). To increase the maximum attainable carrier density for electrostatic tuning of electronic states in semiconductor field-effect transistors is a hot issue but a big challenge. Here, ultrahigh density carrier accumulation is reported, in particular at low temperature, in a ZnO field-effect transistor gated by electric double layers of ionic liquid (IL). This transistor, called an electric double layer transistor (EDLT), is found to exhibit very high transconductance and an ultrahigh carrier density in a fast, reversible, and reproducible manner. The room temperature capacitance of EDLTs is found to be as large as 34,µF cm,2, deduced from Hall-effect measurements, and is mainly responsible for the carrier density modulation in a very wide range. Importantly, the IL dielectric, with a supercooling property, is found to have charge-accumulation capability even at low temperatures, reaching an ultrahigh carrier density of 8×1014 cm,2 at 220,K and maintaining a density of 5.5×1014 cm,2 at 1.8,K. This high carrier density of EDLTs is of great importance not only in practical device applications but also in fundamental research; for example, in the search for novel electronic phenomena, such as superconductivity, in oxide systems. [source] Cover Picture: Fabrication of Stable Metallic Patterns Embedded in Poly(dimethylsiloxane) and Model Applications in Non-Planar Electronic and Lab-on-a-Chip Device Patterning (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 4 2005Mater. Abstract A composite image is shown that highlights examples of device architectures that either incorporate or exploit polymer-embedded metallic microstructures. In work reported by Nuzzo and co-workers on p.,557, new applications of soft lithography, in conjunction with advanced forms of multilayer metallization, are used to construct these exceptionally durable structures. They are suitable for use in non-planar lithographic patterning, and as device components finding applications ranging from microelectronics to Lab-on-a-Chip analytical systems. This article describes the fabrication of durable metallic patterns that are embedded in poly(dimethylsiloxane) (PDMS) and demonstrates their use in several representative applications. The method involves the transfer and subsequent embedding of micrometer-scale gold (and other thin-film material) patterns into PDMS via adhesion chemistries mediated by silane coupling agents. We demonstrate the process as a suitable method for patterning stable functional metallization structures on PDMS, ones with limiting feature sizes less than 5,,m, and their subsequent utilization as structures suitable for use in applications ranging from soft-lithographic patterning, non-planar electronics, and microfluidic (lab-on-a-chip, LOC) analytical systems. We demonstrate specifically that metal patterns embedded in both planar and spherically curved PDMS substrates can be used as compliant contact photomasks for conventional photolithographic processes. The non-planar photomask fabricated with this technique has the same surface shape as the substrate, and thus facilitates the registration of structures in multilevel devices. This quality was specifically tested in a model demonstration in which an array of one hundred metal oxide semiconductor field-effect transistor (MOSFET) devices was fabricated on a spherically curved Si single-crystalline lens. The most significant opportunities for the processes reported here, however, appear to reside in applications in analytical chemistry that exploit devices fabricated using the methods of soft lithography. Toward this end, we demonstrate durably bonded metal patterns on PDMS that are appropriate for use in microfluidic, microanalytical, and microelectromechanical systems. We describe a multilayer metal-electrode fabrication scheme (multilaminate metal,insulator,metal (MIM) structures that substantially enhance performance and stability) and use it to enable the construction of PDMS LOC devices using electrochemical detection. A polymer-based microelectrochemical analytical system, one incorporating an electrode array for cyclic voltammetry and a microfluidic system for the electrophoretic separation of dopamine and catechol with amperometric detection, is demonstrated. [source] High-Performance Flexible Transparent Thin-Film Transistors Using a Hybrid Gate Dielectric and an Amorphous Zinc Indium Tin Oxide ChannelADVANCED MATERIALS, Issue 21 2010Jun Liu High-performance flexible transparent thin-film transistors (TFTs) are demonstrated using amorphous zink indium tin oxide (ZITO) transparent oxide conductor electrodes, an amorphous ZITO transparent oxide semiconductor channel, and a vapor-deposited self-assembled nanodielectric (v-SAND) gate insulator. These TFTs exhibit a large field-effect mobility of 110 cm2V,1s,1, a current on/off ratio of 104, and a low operating voltage of 1.0,V, along with very good optical transparency and mechanical flexibility. [source] Magnetically Tunable Metal,Insulator SuperlatticesADVANCED MATERIALS, Issue 4 2010Masao Nakamura Design and control of nanometer-scale electronic phase separation are demonstrated in high-quality manganite superlattices composed of a ferromagnetic metal and an antiferromagnetic insulator (see figure). Bicritical competition of these phases sensitively controls the magnetic and electronic properties of the superlattices as a whole. A magnetic field can effectively tune the volume fraction of each phase and consequently the position of the phase domain boundaries. [source] Madelung Strain in Cuprate Superconductors , A Route to Enhancement of the Critical TemperatureADVANCED MATERIALS, Issue 36 2009Vladimir Y. Butko "Madelung Strain" in cuprate films containing metal (M,=,La1.56Sr0.44CuO4) and insulator (I,=,La2CuO4) layers: X-ray diffraction shows that, unexpectedly, the volume of unit cell of the top layer adjusts to that of the bottom layer. The effect is due to long-range Coulomb forces; it affects interfacial superconductivity because the critical temperature scales with the unit-cell height. [source] On circuit models for quantum-classical networks,INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS, Issue 5-6 2007Árpád I. Csurgay Abstract Physics is not scale invariant, and today the scale of atoms and molecules challenges designers of machines in which quantum effects have dominant sway. What role could circuit theory play in designing machines described by quantum-classical models? Classical equivalent circuits do exist for systems composed of metal contacted and wired devices, such as resonant tunneling diodes, single electron transistors, metal,insulator,metal diodes, etc. circuits, but not for quantum-entangled networks, such as multi-quantum-state atoms. If devices were not contacted and wired by macroscopic metals, i.e. devices were classically field coupled, then generalized circuit models can be introduced. Case studies have been presented on the role of circuit models in quantum-classical systems. However, there are no ideal circuit elements capable of capturing the port properties of quantum-mechanical and/or quantum-optical subsystems and their coupling to classical waveguides or cavities. Copyright © 2007 John Wiley & Sons, Ltd. [source] Photocurable Organic Gate Insulator for the Fabrication of High-Field Effect Mobility Organic Transistors by Low Temperature and Solution Processing,ADVANCED MATERIALS, Issue 18 2007T.-W. Lee A new organic gate insulator in OTFT devices, which satisfies the requirements for the fabrication of a practical TFT array, such as a good chemical resistance, a low moisture uptake, a low temperature process, and a good film surface smoothness, is introduced. Since this gate insulator film is formed by photo-curing after spincasting on the top of the gate electrode, the process does not require high temperatures. [source] Self-Organized Organic Thin-Film Transistors on Plastic,ADVANCED MATERIALS, Issue 8 2004Y. Choi The development of the self-organized growth of pentacence thin films on the channel region of a thin-film transistor (TFT) using surface modifications induced by organic vapor phase deposition is reported (see Figure). A bottom-contact TFT on plastic using an organic gate insulator of cross-linked poly-(4-vinylphenol) exhibited a field-effect mobility of 1.2 cm2/Vs and an on/off current ratio of ,,107. [source] Fabrication of Highly Conductive 12CaO·7Al2O3 Thin Films Encaging Hydride Ions by Proton ImplantationADVANCED MATERIALS, Issue 13 2003M. Miyakawa Thin films of a new transparent oxide semiconductor 12CaO·7Al2O3 consisting of subnanometer-sized cages (see Figure inset) have been fabricated, and their light-induced insulator,conductor conversion is described. Proton implantation at a fluence of 1,×,1018 cm,2 followed by UV-light irradiation increases the electrical conductivity by more than eleven orders of magnitude to the largest value ,,10 S,cm,1 (see Figure). The conducting state is erasable by heating. [source] Adhesion properties and thermal degradation of silicone rubberJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2007Eung-Soo Kim Abstract Silicone rubber is suitable for the thermal insulator of the rocket motors owing to its heat resisting properties as well as its excellent elasticity and restoring force. However, the adhesion properties of the silicone rubber should be improved greatly to be used as the thermal insulator because of its poor adhesiveness coming from the low surface tension. Functional groups were incorporated through copolymerization to the silicone rubber to induce chemical reaction with the functional groups in the propellant/liner components to enhance the adhesion properties. Peeling tests results disclosed that the incorporation of amine groups was the most efficient for the adhesiveness enhancement and that addition of carbon black improved the adhesiveness still more. Stability against thermal degradation of the silicone rubber was examined by measuring the activation energy through the thermogravimetric analysis. The results revealed that the compounding of the Cloisite® clays boosted up the thermal stability of the silicone rubber much more greatly than that of carbon black. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2782,2787, 2007 [source] | ||||||||||||||||||||||