Science.gov

Sample records for ito substrate modification

  1. ITO DBR electrodes fabricated on PET substrate for organic electronics.

    PubMed

    Tien, W C; Chu, A K

    2014-02-24

    A conductive distributed Bragg reflector (DBR) fabricated on PET substrate using the single indium tin oxide (ITO) material is proposed. The large index contrast of the DBRs was obtained by depositing alternating layers of dense and porous ITO films. The high refractive index of the dense ITO films was achieved by long-throw radio-frequency magnetron sputtering technique at room temperature. On the other hand, the porous ITO films with low refractive index were fabricated by supercritical CO2 (SCCO2) treatment at 60 °C. The index contrast of the dense and porous ITO films as larger as 0.59 at blue spectral range was obtained. For the 4.5-period ITO DBR fabricated on PET substrate, the reflectance and sheet resistance of 85.1% and 47 Ω/◻ were achieved at 475 nm.

  2. Phosphonic Acid Functionalized Asymmetric Phthalocyanines: Synthesis, Modification of Indium Tin Oxide (ITO), and Charge Transfer

    SciTech Connect

    Polaske, Nathan W.; Lin, Hsiao-Chu; Tang, Anna; Mayukh, Mayank; Oquendo, Luis E.; Green, John; Ratcliff, Erin L.; Armstrong, Neal R.; Saavedra, S. Scott; McGrath, Dominic V.

    2011-12-20

    Metalated and free-base A₃B-type asymmetric phthalocyanines (Pcs) bearing, in the asymmetric quadrant, a flexible alkyl linker of varying chain lengths terminating in a phosphonic acid (PA) group have been synthesized. Two parallel series of asymmetric Pc derivatives bearing aryloxy and arylthio substituents are reported, and their synthesis and characterization through NMR, combustion analysis, and MALDI-MS are described. We also demonstrate the modification of indium tin oxide (ITO) substrates using the PA functionalized asymmetric Pc derivatives and monitoring their electrochemistry. The PA functionalized asymmetric Pcs were anchored to the ITO surface through chemisorption and their electrochemical properties characterized using cyclic voltammetry to investigate the effects of PA structure on the thermodynamics and kinetics of charge transfer. Ionization energies of the modified ITO surfaces were measured using ultraviolet photoemission spectroscopy.

  3. Properties of ITO thin films deposited on amorphous and crystalline substrates with e-beam evaporation

    NASA Astrophysics Data System (ADS)

    Wang, R. X.; Beling, C. D.; Djurisic, A. B.; Li, S.; Fung, S.

    2004-06-01

    Indium tin oxide (ITO) thin films were deposited using the e-beam evaporation method on amorphous and crystalline substrates under identical conditions. The properties of the films were investigated using optical transmittance, XRD and XPS techniques. It was found that the properties of the films depend strongly on the nature of the substrate surface. Analysis suggests that changes in chemical composition and microstructure of the ITO films deposited on crystalline and amorphous substrates are responsible for the differences in optical properties.

  4. Thickness Dependence of Properties of ITO Films Deposited on PET Substrates.

    PubMed

    Kim, Seon Tae; Kim, Tae Gyu; Cho, Hyun; Yoon, Su Jong; Kim, Hye Sung; Kim, Jin Kon

    2016-02-01

    Indium tin oxide (ITO) films with various thicknesses from 104 nm to 513 nm were prepared onto polyethylene terephthalate (PET) substrates by using r.f. magnetron sputtering without intentionally heating the substrates. The structural, optical, and electrical properties of ITO films were investigated as a function of film thickness. It was found that the amorphous nature of the ITO film was dominant below the thickness of about 200 nm but the degree of the crystallinity increased with an increasing thickness above the thickness of about 250 nm, resulting in the increase of carrier concentration and therefore reducing the electrical resistivity from 5.1 x 10(-3) to 9.4 x 10(-4) omega x cm. The average transmittance (400-800 nm) of the ITO deposited PET substrates decreased as the film thickness was increasing and was above 80% for the thickness below 315 nm. The results show that the improvement of the film crystallinity with the film thickness contributes to the increase of the carrier concentration and the enhancement of the electrical conductivity.

  5. F2-laser patterning of indium tin oxide (ITO) thin film on glass substrate

    NASA Astrophysics Data System (ADS)

    Xu, M. Y.; Li, J.; Lilge, L. D.; Herman, P. R.

    2006-10-01

    This paper reports the controlled micromachining of 100 nm thick indium tin oxide (ITO) thin films on glass substrates with a vacuum-ultraviolet 157 nm F2 laser. Partial to complete film removal was observed over a wide fluence window from 0.49 J/cm2 to an optimized single pulse fluence of 4.5 J/cm2 for complete film removal. Optical microscopy, atomic force microscopy, and energy dispersive X-ray analysis show little substrate or collateral damage by the laser pulse which conserved the stoichiometry, optical transparency and electrical conductivity of ITO coating adjacent to the trenches. At higher fluence, a parallel micron sized channel can be etched in the glass substrate. The high photon energy and top-hat beam homogenized optical system of the F2 laser opens new means for direct structuring of electrodes and microchannels in biological microfluidic systems or in optoelectronics.

  6. Electrochemical detection of nitrite on poly(pyronin Y)/graphene nanocomposites modified ITO substrate

    NASA Astrophysics Data System (ADS)

    Şinoforoğlu, Mehmet; Dağcı, Kader; Alanyalıoğlu, Murat; Meral, Kadem

    2016-06-01

    The present study reports on an easy preparation of poly(pyronin Y)/graphene (poly(PyY)/graphene) nanocomposites thin films on indium tin oxide coated glass substrates (ITO). The thin films of poly(PyY)/graphene nanocomposites are prepared by a novel method consisting of three steps; (i) preparation of graphene oxide (GO) thin films on ITO by spin-coating method, (ii) self-assembly of PyY molecules from aqueous solution onto the GO thin film, (iii) surface-confined electropolymerization (SCEP) of the adsorbed PyY molecules on the GO thin film. The as-prepared poly(PyY)/graphene nanocomposites thin films are characterized by using electroanalytical and spectroscopic techniques. Afterwards, the graphene-based polymeric dye thin film on ITO is used as an electrode in an electrochemical cell. Its performance is tested for electrochemical detection of nitrite. Under optimized conditions, the electrocatalytical effect of the nanocomposites thin film through electrochemical oxidation of nitrite is better than that of GO coated ITO.

  7. Characterization of sprayed TiO2 on ITO substrates for solar cell applications.

    PubMed

    Arunachalam, A; Dhanapandian, S; Manoharan, C; Sridhar, R

    2015-10-05

    Titanium dioxide (TiO2) thin films had been deposited with various substrate temperatures by spray pyrolysis technique onto ITO substrates. All films exhibited polycrystalline nature with the preferred orientation along (101) plane. At the substrate temperature 450 °C, the film favored the formation of anatase phase. The higher substrate temperature (475 °C) favored the appearance of rutile structure. The SEM image of the film at substrate temperature (Ts=450 °C) showed high structural quality with the porous nature. The typical AFM image of TiO2 film deposited at the substrate temperature, 450 °C depicted the regular arrangement of fine closely packed tetragonal structured grains. The transmittance of the spectra exhibited above 85% with energy band gap of 3.6 eV. From the study of photoluminescence, the emission at 417 nm, 437 nm and with weak emission at 551 nm was observed, which confirmed the lesser defects in the samples. The electrical resistivity was found to be 6.856×10(1) Ω cm for the substrate temperature 450 °C. The efficiency of anatase TiO2 photoelectrode deposited at the substrate temperature 450 °C based cell was much higher than the efficiency of TiO2 photoelectrode deposited at the substrate temperature 475 °C based cell.

  8. Laser scribing of indium tin oxide (ITO) thin films deposited on various substrates for touch panels

    NASA Astrophysics Data System (ADS)

    Tseng, Shih-Feng; Hsiao, Wen-Tse; Huang, Kuo-Cheng; Chiang, Donyau; Chen, Ming-Fei; Chou, Chang-Pin

    2010-12-01

    In this study, a Nd:YAG laser with wavelength of 1064 nm is used to scribe the indium tin oxide (ITO) thin films coated on three types of substrate materials, i.e. soda-lime glass, polycarbonate (PC), and cyclic-olefin-copolymer (COC) materials with thickness of 20 nm, 30 nm, and 20 nm, respectively. The effect of exposure time adjusted from 10 μs to 100 μs on the ablated mark width, depth, and electrical properties of the scribed film was investigated. The maximum laser power of 2.2 W was used to scribe these thin films. In addition, the surface morphology, surface reaction, surface roughness, optical properties, and electrical conductivity properties were measured by a scanning electron microscope, a three-dimensional confocal laser scanning microscope, an atomic force microscope, and a four-point probe. The measured results of surface morphology show that the residual ITO layer was produced on the scribed path with the laser exposure time at 10 μs and 20 μs. The better edge qualities of the scribed lines can be obtained when the exposure time extends from 30 μs to 60 μs. When the laser exposure time is longer than 60 μs, the partially burned areas of the scribed thin films on PC and COC substrates are observed. Moreover, the isolated line width and resistivity values increase when the laser exposure time increases.

  9. Design and development of plasmonic nanostructured electrodes for ITO-free organic photovoltaic cells on rigid and highly flexible substrates

    NASA Astrophysics Data System (ADS)

    Richardson, Beau J.; Zhu, Leize; Yu, Qiuming

    2017-04-01

    Indium tin oxide (ITO) is the most common transparent electrode used in organic photovoltaics (OPVs), yet limited indium reserves and poor mechanical properties make it non-ideal for large-scale OPV production. To replace ITO, we designed, fabricated, and deployed plasmonic nanostructured electrodes in inverted OPV devices. We found that active layer absorption is significantly impacted by ZnO thickness which affects the optical field distribution inside the resonant cavity formed between the plasmonic nanostructured electrode and top electrode. High quality Cr/Au nanostructured electrodes were fabricated by nanoimprint lithography and deployed in ITO-free inverted devices on glass. Devices with thinner ZnO showed a PCE as high as 5.70% and higher J SC’s than devices on thicker ZnO, in agreement with finite-difference time-domain simulations. In addition, as the active layer was made optically thin, ITO-based devices showed diminished J SC while the resonant cavity effect from plasmonic nanostructured electrodes retained J SC. Preliminary ITO-free, flexible devices on PET showed a PCE of 1.82% and those fabricated on ultrathin and conformable Parylene substrates yielded an initial PCE over 1%. The plasmonic electrodes and device designs in this work show promise for developing highly functioning conformable devices that can be applied to numerous needs for lightweight, ubiquitous power generation.

  10. Design and development of plasmonic nanostructured electrodes for ITO-free organic photovoltaic cells on rigid and highly flexible substrates.

    PubMed

    Richardson, Beau J; Zhu, Leize; Yu, Qiuming

    2017-04-21

    Indium tin oxide (ITO) is the most common transparent electrode used in organic photovoltaics (OPVs), yet limited indium reserves and poor mechanical properties make it non-ideal for large-scale OPV production. To replace ITO, we designed, fabricated, and deployed plasmonic nanostructured electrodes in inverted OPV devices. We found that active layer absorption is significantly impacted by ZnO thickness which affects the optical field distribution inside the resonant cavity formed between the plasmonic nanostructured electrode and top electrode. High quality Cr/Au nanostructured electrodes were fabricated by nanoimprint lithography and deployed in ITO-free inverted devices on glass. Devices with thinner ZnO showed a PCE as high as 5.70% and higher J SC's than devices on thicker ZnO, in agreement with finite-difference time-domain simulations. In addition, as the active layer was made optically thin, ITO-based devices showed diminished J SC while the resonant cavity effect from plasmonic nanostructured electrodes retained J SC. Preliminary ITO-free, flexible devices on PET showed a PCE of 1.82% and those fabricated on ultrathin and conformable Parylene substrates yielded an initial PCE over 1%. The plasmonic electrodes and device designs in this work show promise for developing highly functioning conformable devices that can be applied to numerous needs for lightweight, ubiquitous power generation.

  11. Surface Modification of Nanocellulose Substrates

    NASA Astrophysics Data System (ADS)

    Zoppe, Justin Orazio

    Cellulose fibers constitute an important renewable raw material that is utilized in many commercial applications in non-food, paper, textiles and composite materials. Chemical functionalization is an important approach for improving the properties of cellulose based materials. Different approaches are used to graft polymeric chains onto cellulose substrates, which can be classified by two principal routes, namely 'grafting onto' or 'grafting from' methods. Never-dried cellulose nanocrystals (CNCs) or nanowhiskers produced from sulfuric acid hydrolysis of ramie fibers were used as substrates for surface chemical functionalization with various macromolecules. In addition, the use of cellulose nanocrystals to reinforce poly(epsilon-caprolactone) (PCL) nanofibers was studied. Chemical grafting with low molecular weight polycaprolactone diol onto cellulose nanocrystals was carried out in an attempt to improve the interfacial adhesion with the fiber matrix. Significant improvements in the mechanical properties of the nanofibers after reinforcement with unmodified cellulose nanocrystals were confirmed. Fiber webs from PCL reinforced with 2.5% unmodified CNCs showed ca. 1.5-fold increase in Young's modulus and ultimate strength compared to PCL webs. The CNCs were also grafted with poly(N-isopropylacrylamide) (poly(NiPAAm)) brushes via surface-initiated single-electron transfer living radical polymerization (SI-SETLRP) under various conditions at room temperature. The grafting process depended on the initiator and/or monomer concentrations used. No observable damage occurred to the CNCs after grafting, as determined by X-ray diffraction. Size exclusion chromatography analyses of polymer chains cleaved from the cellulose nanocrystals indicated that a higher degree of polymerization was achieved by increasing initiator or monomer loading, most likely caused by local heterogeneities yielding higher rates of polymerization. In addition, the colloidal stability and thermo

  12. Optical properties of Au-Ag core-shell nanorods on glass and ITO substrates

    NASA Astrophysics Data System (ADS)

    Tsuru, Yukiko; Nakashima, Naotoshi; Niidome, Yasuro

    2012-07-01

    Gold-silver core-shell nanorods were deposited on glass and ITO plates. SEM observations indicated that some of these nanorods were standing on the ITO plate. The extinction spectra of the plates were measured by varying the angles of incidence of p-polarized monitor light. Deconvolution of these spectra gave six bands in the visible region. The dependence of the peak intensities on the incident angles indicated that the bands at 390 and 420 nm originated from surface plasmon bands in the transverse direction of the nanorods.

  13. Synthesis and Analysis of MnTiO3 Thin Films on ITO Coated Glass Substrates

    NASA Astrophysics Data System (ADS)

    Martin, Emerick; Sahiner, Mehmet-Alper

    Perovskites like Manganese Titanium Oxide have interesting chemical properties that may be advantageous to the development of p-n junction photovoltaic cells. Due to the limited understanding behind the compound, it is essential to know the characteristics of it when it is deposited in thin film form. The cells were created using pulsed laser deposition method for two separate mediums (first layers after ITO). ZnO was deposited onto ITO glass for the first sample. For the second sample, a layer of pure Molybdenum was deposited onto the ITO glass. The MnTiO3 was then deposited onto both samples. There was a target thickness of 1000 Angstroms, but ellipsometry shows that, for the Mo based sample, that film thickness was around 1500 Angstroms. There were inconclusive results for the ZnO based sample. The concentration of active carriers was measured using a Hall Effect apparatus for the Mo based sample. The XRD analyses were used to confirm the perovskite structure of the films. Measurements for photoelectric conversion efficiency were taken using a Keathley 2602 ScourceMeter indicated low values for efficiency. The structural information that is correlated with the low electrical performance of this sample will be discussed. SHU-NJSGC Summer 2015 Fellowship.

  14. Effects of substrate bias power on the surface of ITO electrodes during O2/CF4 plasma treatment and the resulting performance of organic light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Han, D. M.; Lee, J. H.; Jeong, K. H.; Lee, J. G.

    2010-08-01

    During surface treatment using O2/CF4 plasma chemistry, the bias power applied to the indium-tin-oxide(ITO) substrate significantly degrades the electrical and optical performance of the organic light emitting diode (OLED) formed on the ITO electrode as a result of the formation of CFx polymer, In-Sn-F compounds, and structural defects. Application of bias power to the substrate effectively increases the sheath potential over the substrate and thus the flux of CFx + ion created in the O2/CF4 plasma, which leads to the production of CFx polymers as well as structural defects.

  15. Electrochemical growth of CoNi and Pt-CoNi soft magnetic composites on an alkanethiol monolayer-modified ITO substrate.

    PubMed

    Escalera-López, D; Gómez, E; Vallés, E

    2015-07-07

    CoNi and Pt-CoNi magnetic layers on indium-tin oxide (ITO) substrates modified by an alkanethiol self-assembled monolayer (SAM) have been electrochemically obtained as an initial stage to prepare semiconducting layer-SAM-magnetic layer hybrid structures. The best conditions to obtain the maximum compactness of adsorbed layers of dodecanethiol (C12-SH) on ITO substrate have been studied using contact angle, AFM, XPS and electrochemical tests. The electrochemical characterization (electrochemical probe or voltammetric response in blank solutions) is fundamental to ensure the maximum blocking of the substrate. Although the electrodeposition process on the SAM-modified ITO substrate is very slow if the blocking of the surface is significant, non-cracked metallic layers of CoNi, with or without a previously electrodeposited seed-layer of platinum, have been obtained by optimizing the deposition potentials. Initial nucleation is expected to take place at the pinhole defects of the C12-SH SAM, followed by a mushroom-like growth regime through the SAM interface that allows the formation of a continuous metallic layer electrically connected to the ITO surface. Due to the potential of the methodology, the preparation of patterned metallic deposits on ITO substrate using SAMs with different coverage as templates is feasible.

  16. Optoelectronic properties and interfacial durability of CNT and ITO on boro-silicate glass and PET substrates with nano- and heterostructural aspects

    NASA Astrophysics Data System (ADS)

    Park, Joung-Man; Wang, Zuo-Jia; Kwon, Dong-Jun; DeVries, Lawrence

    2011-02-01

    Nano- and hetero-structures of carbon nanotube (CNT) and indium tin oxide (ITO) can control significantly piezoelectric and optoelectronic properties in Microelectromechanical Systems (MEMS) as sensing and actuator under cyclic loading. Optimized preparing conditions were obtained for multi-functional purpose of the specimen by obtaining the best dispersion and turbidity in the solution. Optical transmittance and electrical properties were investigated for CNT and ITO dipping and spraying coating on boro-silicate glass and polyethylene terephthalate (PET) substrates by electrical resistance measurement under cyclic loading and wettability test. Uniform dip-coating was performed using Wilhelmy plate method due to its simple and convenience. Spraying coating was applied to the specimen additionally. The change in the electrical resistance and optical properties of coated layer were mainly dependent upon the number of dip-coating, the concentration of CNT and ITO solutions, and the surface treatment condition. Electric properties of coating layers were measured using four-point probe method, and surface resistance was calculated using a dual configuration method. Optical transmittance of CNT and ITO coated PET film was also evaluated using UV spectrum. Surface energy and their hydrophilic and hydrophobic properties of CNT and ITO coated substrates were investigated by wettability test via static and dynamic contact angle measurements. As the elapsing time of cyclic loading passed, the stability of surface resistance and thus comparative interfacial adhesion between coated layer and substrates was evaluated to compare the thermodynamic work of adhesion, Wa. As dip-coating number increased, surface resistance of coated CNT decreased, whereas the transmittance decreased step-by-step due to the thicker CNT and ITO networked layer. Nano- and heterostructural effects of CNT and ITO solution on the optical and electrical effects have been studied continuously.

  17. Fabrication of hetero-junction diode using NiO thin film on ITO/glass substrate

    NASA Astrophysics Data System (ADS)

    Soni, Sonali; Sharma, Vinay; Kuanr, Bijoy K.

    2016-05-01

    Fabrication, characterization and testing of hetero-junctions of NiO thin films were done. Nickel films were evaporated on polished ITO coated glass substrates using thermal deposition. The films were annealed at high temperatures in the presence of oxygen to obtain NiO films. The rectifying current-voltage (I-V) properties confirmed that a hetero-junction diode was successfully formed. The AC and DC behavior of hetero-junction using DC silver-probes were determined. The threshold voltage, ideality factor and reverse saturation current of hetero junction were determined. We have compared these I-V characteristics with semiconducting PN junction diode. To test the device characteristics, we used the structure as a diode clipper at various frequencies. It is showed that our device is a better high-frequency junction-device than a normal PN junction diode.

  18. Facile fabrication of crack-free large-area 2D WO3 inverse opal films by a 'dynamic hard-template' strategy on ITO substrates.

    PubMed

    Li, Hua; Thériault, Jolaine; Rousselle, Bruno; Subramanian, Balaji; Robichaud, Jacques; Djaoued, Yahia

    2014-02-28

    A 'dynamic hard-template' infiltration strategy for crack-free large-area synthesis of 2D WO3 inverse opal (IO) films on ITO substrates using a wide range of sizes of sacrificial PS spheres is reported. Thus prepared WO3 IO films were successfully used as an active electrode in the fabrication of an electrochromic device.

  19. Back interface effect on the topography and magnetism relationship studied from Ni nano-coatings: role of ITO and Cu substrates

    NASA Astrophysics Data System (ADS)

    Ebothé, Jean; Nzoghe-Mendome, Lény; Khamis Aloufy, Affaf

    2015-12-01

    A comparative study is here reported on the role of ITO and Cu substrates in the surface growth, topography and the magnetism of mesoscopic scale thick nanocrystallized Ni electrocoatings in the thickness interval 60 < d < 1200 nm. The cathodic voltammetry (C-V) technique used for the coating formation engenders conglomerated grain patterns with ITO and spaced needle-like features with Cu. These surface configurations are particularly marked with the thinnest samples. They undergo a noticeable smoothing with the coating thickness increase. The magnetic reversal (MR) of the Ni samples on Cu is ruled by the spin rotation mechanism. A transition from the domain wall (DW) motion mechanism to the spin rotation one occurs with ITO while the d value increases. The study of the topography-magnetism relationship reveals that the spin rotation mechanism of the Ni samples is incoherent with both substrates. The co-existence of the Bloch magnetic domains (MD)B and the Néel domain wall (DW)N types is identified for ITO in the thinner (rougher) Ni samples associated with the DW motion MR. The same sequence occurs for Cu for the thicker (smoother) samples linked to the spin rotation MR, as long as their normalized roughness values are confined below σ o‧ ≈ 0.15.

  20. Evaluation of the single yeast cell's adhesion to ITO substrates with various surface energies via ESEM nanorobotic manipulation system.

    PubMed

    Shen, Yajing; Ahmad, Mohd Ridzuan; Nakajima, Masahiro; Kojima, Seiji; Homma, Michio; Fukuda, Toshio

    2011-12-01

    Cell-surface adhesion force is important for cell activities and the development of bio materials. In this paper, a method for in situ single cell (W303) adhesion force measurement was proposed based on nanorobotic manipulation system inside an environment scanning electron microscope (ESEM). An end effector was fabricated from a commercial atomic force microscope (AFM) cantilever by focused ion beam (FIB) etching. The spring constant of it was calibrated by nanomanipulation approach. Three kinds of hydrophilic and hydrophobic ITO plates were prepared by using VUV-irradiation and OTS coating techniques. The shear adhesion strength of the single yeast cell to each substrate was measured based on the deflection of the end effector. The results demonstrated that the cell adhesion force was larger under the wet condition in the ESEM environment than in the aqueous condition. It also showed that the cell adhesion force to hydrophilic surface was larger than that to the hydrophobic surface. Studies of single cell's adhesion on various plate surfaces and environments could give new insights into the tissue engineering and biological field.

  1. Efficient photocatalytic decolorization of some textile dyes using Fe ions doped polyaniline film on ITO coated glass substrate.

    PubMed

    Haspulat, Bircan; Gülce, Ahmet; Gülce, Handan

    2013-09-15

    In this study, the photocatalytic decolorization of four commercial textile dyes with different structures has been investigated using electrochemically synthesized polyaniline and Fe ions doped polyaniline on ITO coated glass substrate as photocatalyst in aqueous solution under UV irradiation for the first time. Scanning electron microscopy, atomic force microscopy, FT-IR spectra, UV-vis spectroscopy measurements were used to characterize the electrochemically synthesized polymer film photocatalyst. Film hydrophilicity was assessed from contact angle measurements. The results show that both of the polymer films exhibit good photocatalytic performance. Surprisingly, it was determined that by using Fe(II) ions during polymerization, it is possible to modify the surface roughness and wettability of the produced polyaniline films which favors their photocatalytic activity in water-based solutions. All four of the used dyes (methylene blue, malachite green, methyl orange and methyl red) were completely decolorizated in 90 min of irradiation under UV light by using Fe ions doped polyaniline at the dye concentration of 1.5 × 10(-5)M, while the decolorization of those dyes were between 43% and 83% by using polyaniline as photocatalyst. Hence, it may be a viable technique for the safe disposal of textile wastewater into waste streams.

  2. Ferroelectric Properties of CaBi4Ti4O15 Thin Films on Ito/glass Substrates Prepared by Sol-Gel Technology

    NASA Astrophysics Data System (ADS)

    Cheng, Chien-Min; Kuan, Ming-Chang; Chen, Kai-Hunag; Tsai, Jen-Hwan

    In this study, ferroelectric CaBi4Ti4O15 (CBT) thin films prepared by sol-gel method and deposited on ITO/glass substrates for applications in system-on-panel (SOP) devices were fabricated and investigated. The electrical and physical characteristics of as-deposited and annealed CBT thin films for metal-ferroelectric-metal (MFM) structures was discussed and investigated. In addition, the ferroelectric properties in annealed CBT thin films on ITO/glass substrate showed and exhibited clear polarization versus electrical field curves. From p-E curves, the 2Pr value and coercive field of annealed CBT thin films were calculated to be 10μC/cm2 and 180 kV/cm, respectively. Finally, the maximum capacitance, leakage current density, and transmittance within the ultraviolet-visible (UV-vis) spectrum were also investigated and discussed.

  3. Electrical Properties Analysis of Copper doped CdTe/CdS Deposited Thin Films on ITO Coated Glass Substrates

    NASA Astrophysics Data System (ADS)

    Lesinski, Darren; Flaherty, James; Sahiner, M. Alper

    CdTe proves to be a viable source for renewable energy in the form of photovoltaic conversion. While CdTe/CdS naturally provide interesting results adding dopants to the cell can yield higher conversion efficiencies. Copper, famous for its electrical properties, can be used as a dopant in the CdTe layer. In conjunction with its dopant characteristics Copper also improves cell performance by acting as a low resistant and high current back contact. All thin films were synthesized using pulsed laser deposition onto ITO coated glass substrates. The CdS layer across all cells has an approximate thickness of 1500 Angstroms. The following CdTe layer has an approximate thickness of 5500 Angstroms. This created the base cell that was then doped. Cu, typically deposited using sublimation or vapor deposition, was done by PLD as well. Two of the three base cells were treated with Cu using the same deposition parameters. The third cell also received a CdCl treatment on top of the Cu layer to understand the effect when the oxygen layer is deferred. Ellipsometer measurements were used to confirm layer thickness. XRD analysis was used to confirm the presence of Cu and the crystal structure of the thin films. A Hall Effect Measurement system was used to measure active charge carrier concentration introduced by dopant. Also, a Keithley sourcemeter was utilized to determine photovoltaic properties. Notable results discussed will be the effects of Copper dopant on the electrical properties of CdS/CdTe based solar cells.

  4. Inorganic Surface Modification of Nonwoven Polymeric Substrates

    NASA Astrophysics Data System (ADS)

    Halbur, Jonathan Chandler

    In this study, atomic layer deposition (ALD), a vapor phase inorganic thin film deposition technique, is used to modify the surface of a range of industrially relevant polymers to enhance surface properties or impart additional functionalities. Several unique demonstrations of polymer surface modification are presented including uniform nanomaterial photodeposition to the surface of nonowoven fabrics and the first application of photocatalytic thin film coated nonwovens for advanced filtration of heavy metals from solution. Recent advances in polymer synthesis and processing technologies have resulted in the production of novel polymer systems with unique chemistries and sub-micron scale dimensions. As a result, advanced fiber systems have received much attention for potential use in a wide range of industrially and medically important applications such as advanced and selective filtration, catalysis, flexible electronics, and tissue engineering. However, tailoring the surface properties of the polymer is still needed in order to realize the full range of advanced applications, which can be difficult given the high complexity and non-uniformity of nonwoven polymeric structures. Uniform and controllable inorganic surface modification of nonwovens allows the introduction or modification of many crucial polymer properties with a wide range of application methods.

  5. ITO/poly(aniline)/sol-gel glass: An optically transparent, pH-responsive substrate for supported lipid bilayers.

    PubMed

    Al-Obeidi, Ahmed; Ge, Chenhao; Orosz, Kristina S; Saavedra, S Scott

    2013-01-01

    Described here is fabrication of a pH-sensitive, optically transparent transducer composed of a planar indium-tin oxide (ITO) electrode overcoated with a a poly(aniline) (PANI) thin film and a porous sol-gel layer. Adsorption of the PANI film renders the ITO electrode sensitive to pH, whereas the sol-gel spin-coated layer makes the upper surface compatible with fusion of phospholipid vesicles to form a planar supported lipid bilayer (PSLB). The response to changes in the pH of the buffer contacting the sol-gel/PANI/ITO electrode is pseudo-Nernstian with a slope of 52 mV/pH over a pH range of 4-9. Vesicle fusion forms a laterally continuous PSLB on the upper sol-gel surface that is fluid with a lateral lipid diffusion coefficient of 2.2 μm(2)/s measured by fluorescence recovery after photobleaching. Due to its lateral continuity and lack of defects, the PSLB blocks the pH response of the underlying electrode to changes in the pH of the overlying buffer. This architecture is simpler to fabricate than previously reported ITO electrodes derivatized for PSLB formation, and should be useful for optical monitoring of proton transport across supported membranes derivatized with ionophores and ion channels.

  6. Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET-ITO flexible substrates by hydrothermal method.

    PubMed

    Wang, Wei; Ai, Taotao; Yu, Qi

    2017-02-13

    Boron-doped zinc oxide sheet-spheres were synthesized on PET-ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET-ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET-ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET-ITO were 0.055 mA/cm(2) and 0.016 mA/cm(2), respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory.

  7. Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET–ITO flexible substrates by hydrothermal method

    PubMed Central

    Wang, Wei; Ai, Taotao; Yu, Qi

    2017-01-01

    Boron-doped zinc oxide sheet-spheres were synthesized on PET–ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET–ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET–ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET–ITO were 0.055 mA/cm2 and 0.016 mA/cm2, respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory. PMID:28211923

  8. Electrical and photocatalytic properties of boron-doped ZnO nanostructure grown on PET–ITO flexible substrates by hydrothermal method

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Ai, Taotao; Yu, Qi

    2017-02-01

    Boron-doped zinc oxide sheet-spheres were synthesized on PET–ITO flexible substrates using a hydrothermal method at 90 °C for 5 h. The results of X-ray diffraction and X-ray photoelectron spectroscopy indicated that the B atoms were successfully doped into the ZnO lattice, the incorporation of B led to an increase in the lattice constant of ZnO and a change in its internal stress. The growth mechanism of pure ZnO nanorods and B-doped ZnO sheet-spheres was specifically investigated. The as-prepared BZO/PET–ITO heterojunction possessed obvious rectification properties and its positive turn-on voltage was 0.4 V. The carrier transport mechanisms involved three models such as hot carrier tunneling theory, tunneling recombination, and series-resistance effect were explored. The BZO/PET–ITO nanostructures were more effective than pure ZnO to degrade the RY 15, and the degradation rate reached 41.45%. The decomposition process with BZO nanostructure followed first-order reaction kinetics. The photocurrent and electrochemical impedance spectroscopy revealed that the B-doping could promote the separation of photo-generated electron-hole pairs, which was beneficial to enhance the photocatalytic activity. The photocurrent density of B-doped and pure ZnO/PET–ITO were 0.055 mA/cm2 and 0.016 mA/cm2, respectively. The photocatalytic mechanism of the sample was analyzed by the energy band theory.

  9. Electrooptical properties and structural features of amorphous ITO

    SciTech Connect

    Amosova, L. P.

    2015-03-15

    Thin indium-tin oxide (ITO) films are deposited onto cold substrates by magnetron-assisted sputtering. The dependences of the structural, electrical, and optical properties of the films on the oxygen content in the atmosphere of sputtering and the growth rate are studied. It is shown that, if the substrate temperature is no higher than the ITO crystallization temperature and the conditions of growth deviate from the optimal relationship between the oxygen pressure and the growth rate, the resistance of the layers can be six or seven orders of magnitude higher than the resistance of conducting amorphous layers and reach hundreds of megaohms. At the same time, the optical properties of insulating layers in the visible spectral region are completely identical to the properties of the conducing amorphous modification. A conceptual model of defects responsible for the insulating properties of amorphous ITO is proposed.

  10. Transparent, superhydrophobic, and wear-resistant coatings on glass and polymer substrates using SiO2, ZnO, and ITO nanoparticles.

    PubMed

    Ebert, Daniel; Bhushan, Bharat

    2012-08-07

    It is of significant interest to create surfaces that simultaneously exhibit high water contact angle, low contact angle hysteresis, and high transmission of visible light, as well as mechanical wear resistance for industrial applications. The fabrication of such surfaces has often involved complex or expensive processes, required techniques that were not suitable for a variety of substrates and particles, required surface post-treatment, or lacked wear resistance. A systematic study has been performed in which transparent superhydrophobic surfaces were created on glass, polycarbonate, and poly(methyl methacrylate) (PMMA) substrates using surface-functionalized SiO(2), ZnO, and indium tin oxide (ITO) nanoparticles. The contact angle, contact angle hysteresis, and optical transmittance were measured for samples using all particle-substrate combinations. To examine wear resistance, multiscale wear experiments were performed using an atomic force microscope (AFM) and a water jet apparatus.

  11. High-performance of PEDOT/PSS free organic solar cells on an air-plasma-treated ITO substrate.

    PubMed

    Choi, Jong Kil; Jin, Ming Liang; An, Cheng Jin; Kim, Dae Woo; Jung, Hee-Tae

    2014-07-23

    In this work, we demonstrate the high-performance of a PEDOT:PSS free organic photovoltaic cell (OPVC) using an air-plasma modified ITO surface, followed by controlled solvent evaporation and annealing of the P3HT:PCBM photoactive layer. Ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), and conductive atomic force microscopy (c-AFM) results show that the work function of ITO was increased to as high as that of PEDOT:PSS (5.2 eV) after air-plasma treatment, along with significantly enhanced electrical homogeneity. From the dynamic secondary ion mass spectroscopy (DSIMS) results, we confirm that the thermodynamic stability of the slow-dried active layer is attributed to the uniform vertical compositional distribution on the air plasma treated ITO surface, even after thermal annealing at 150 °C for 10 min. The resulting device has an open-circuit voltage of 0.65 V, a fill factor of 63%, and a power conversion efficiency of 3.38%, providing a high performance PEDOT:PSS free OPVC device.

  12. Structure, optical and electrical properties of Bi2VO5.5 films deposited on ITO/glass substrates by chemical solution method

    NASA Astrophysics Data System (ADS)

    Guo, Ming; Shen, Yude; Liu, Changxin; Yang, Pingxiong

    2011-02-01

    Bismuth vanadate (Bi2VO5.5) thin films were fabricated on indium-doped tin oxide (ITO)-coated glass substrates by chemical solution method combined with a rapid thermal annealing process. The structure of the films was characterized with X-ray diffraction and atomic force microscopy. The Bi2VO5.5 films annealed at 600 °C showed a good match with the ITO coated glass substrates and had a desired perovskite structure with high (00l) preferred orientation. The spherical grains with a homogeneous distribution of high crystallinity and packing density were observed. Optical properties of the Bi2VO5.5 thin films were studied by Raman spectra and the lattice vibration modes of the films were obtained. A low frequency dielectric dispersion was observed in the films. Dielectric constant and loss was about 75 and 0.076 at 10kHz, respectively. The ac conductivity obeyed Jonscher's universal power law, which may be originated a possible hopping mechanism for Bi2VO5.5 thin films. The complex impedance traces revealed material dielectric dispersion nature and the presence of grain effects in the films.

  13. CuS p- type thin film characterization deposited on Ti, ITO and glass substrates using spray pyrolysis deposition (SPD) for light emitting diode (LED) application

    NASA Astrophysics Data System (ADS)

    Sabah, Fayroz A.; Ahmed, Naser M.; Hassan, Z.; Rasheed, Hiba S.; Azzez, Shrook A.; Al-Hazim, Nabeel Z.

    2016-07-01

    The copper sulphide (CuS) thin films were grown with good adhesion by spray pyrolysis deposition (SPD) on Ti, ITO and glass substrates at 200 °C. The distance between nozzle and substrate is 30 cm. The composition was prepared by mixing copper chloride CuCl2.2H2O as a source of Cu2+ and sodium thiosulfate Na2S2O3.5H2O as a source of and S2-. Two concentrations (0.2 and 0.4 M) were used for each CuCl2 and Na2S2O3 to be prepared and then sprayed (20 ml). The process was started by spraying the solution for 3 seconds and after 10 seconds the cycle was repeated until the solution was sprayed completely on the hot substrates. The structural characteristics were studied using X-ray diffraction; they showed covellite CuS hexagonal crystal structure for 0.2 M concentration, and covellite CuS hexagonal crystal structure with two small peaks of chalcocite Cu2S hexagonal crystal structure for 0.4 M concentration. Also the surface and electrical characteristics were investigated using Field Emission Scanning Electron Microscopy (FESEM) and current source device, respectively. The surface study for the CuS thin films showed nanorods to be established for 0.2 M concentration and mix of nanorods and nanoplates for 0.4 M concentration. The electrical study showed ohmic behavior and low resistivity for these films. Hall Effect was measured for these thin films, it showed that all samples of CuS are p- type thin films and ensured that the resistivity for thin films of 0.2 M concentration was lower than that of 0.4 M concentration; and for the two concentrations CuS thin film deposited on ITO had the lowest resistivity. This leads to the result that the conductivity was high for CuS thin film deposited on ITO substrate, and the conductivity of the three thin films of 0.2 M concentration was higher than that of 0.4 M concentration.

  14. SURFACE MODIFICATION OF ZIRCALOY-4 SUBSTRATES WITH NICKEL ZIRCONIUM INTERMETALLICS

    SciTech Connect

    Luscher, Walter G.; Gilbert, Edgar R.; Pitman, Stan G.; Love, Edward F.

    2013-02-01

    Surfaces of Zircaloy-4 (Zr-4) substrates were modified with nickel-zirconium (NiZr) intermetallics to tailor oxidation performance for specialized applications. Surface modification was achieved by electroplating Zr-4 substrates with nickel (Ni) and then performing thermal treatments to fully react the Ni plating with the substrates, which resulted in a coating of NiZr intermetallics on the substrate surfaces. Both plating thickness and thermal treatment were evaluated to determine the effects of these fabrication parameters on oxidation performance and to identify an optimal surface modification process. Isothermal oxidation tests were performed on surface-modified materials at 290°, 330°, and 370°C under a constant partial pressure of oxidant (i.e., 1 kPa D2O in dry Ar at 101 kPa) for 64 days. Test results revealed an enhanced, transient oxidation rate that decreased asymptotically toward the rate of the Zr-4 substrate. Oxidation kinetics were analyzed from isothermal weight gain data, which were correlated with microstructure, hydrogen pickup, strength, and hardness.

  15. Growth and physical properties of p-Zn x Cd1- x S thin films thermally evaporated on ITO-coated glass substrates

    NASA Astrophysics Data System (ADS)

    Yoon, Eun Jeong; Han, Dong Hun; Lee, Jeoung Ju; Lee, Jong Duk; Kang, Kwang Yong; Lee, Seung Hwan; Shewale, Prashant Shivaji

    2015-01-01

    Zn x Cd1- x S ( x = 0.15, 0.44, 0.62, 0.80, and 0.95) thin films of about 340 nm in thickness were deposited on indium-tin-oxide (ITO)-coated glass substrates by using thermal evaporation of high-purity ZnS and CdS mixed tablets in high vacuum. X-ray diffraction spectra showed that the Zn x Cd1- x S thin films were preferentially grown along the (111) orientation. The Zn x Cd1- x S crystal structure was a mixture structure of the ZnS and the CdS cubic zincblende structures with lattice constants a = 5.670 Å to a = 5.734 Å for CdS and a = 5.437 Å for ZnS. The ( αh ν)2 vs. h ν plots for the Zn x Cd1- x S thin films showed that all samples had direct transition band gaps. The energy band gaps of the Zn x Cd1- x S thin films increased monotonically from 2.45 eV for x = 0.15 to 3.37 eV for x = 0.95. The dynamical behavior of the charge carriers in the Zn x Cd1- x S thin films was investigated by using the photoinduced discharge characteristics (PIDC) technique.

  16. Ultrahydrophobic surface modification of polymeric fibers and inorganic substrates

    NASA Astrophysics Data System (ADS)

    Ramaratnam, Karthik

    The wettability of a solid surface is a very important property, and is governed by both the chemical composition and the geometrical microstructure of the surface. Wettability and repellency are important properties of solid surfaces from both fundamental and practical aspects. The wettability of the solid surface is a characteristic property of materials and strongly depends on both the surface energy and the surface roughness. These properties may be approached by mimicking hydrophobic structures created by nature on lotus leaf surface. The lotus effect is based on surface roughness caused by different microstructures together with the hydrophobic properties of the epicuticular wax. The present study investigates the basic principles involved in the fabrication of lotus-like materials on both fibrous and inorganic substrates utilizing the two essential requirements, surface roughness and hydrophobicity. The surface roughness was created either by a porous or a bumpy profile while the hydrophobicity was achieved by grafting a non-fluorinated hydrophobic polymer. For the porous profiles, polymer blend systems showing phase separation were utilized whereas the bumpy profiles were achieved using nanoparticles such as calcium carbonate, silver, or silica particles. In the last part of the research, functionalization of silica nanoparticles was investigated and the development of a universal modification step to obtain the ultrahydrophobic property is reported. In this approach, the adsorption of the polymer and the nanoparticles to fibers has been optimized and the self-cleaning effect of these fabrics modified with silica nanoparticles has also been demonstrated.

  17. Studies on polyurethane adhesives and surface modification of hydrophobic substrates

    NASA Astrophysics Data System (ADS)

    Krishnamoorthy, Jayaraman

    studies involved making functionalized, thickness-controlled, wettability-controlled multilayers on hydrophobic substrates and the adsorption of carboxylic acid-terminated poly(styrene-b-isoprene) on alumina/silica substrates. Poly(vinyl alcohol) has been shown to adsorb onto hydrophobic surfaces irreversibly due to hydrophobic interactions. This thin semicrystalline coating is chemically modified using acid chlorides, butyl isocyanate and butanal to form thicker and hydrophobic coatings. The products of the modification reactions allow adsorption of a subsequent layer of poly(vinyl alcohol) that could subsequently be hydrophobized. This 2-step (adsorption/chemical modification) allows layer-by-layer deposition to prepare coatings with thickness, chemical structure and wettability control on any hydrophobic surface. Research on adsorption characteristics of carboxylic acid-terminated poly(styrene-b-isoprene) involved syntheses of block copolymers with the functional group present at specific ends. Comparative adsorption studies for carboxylic acid-terminated and hydrogen-terminated block copolymers was carried out on alumina and silica substrates.

  18. Preparation of regularly structured nanotubular TiO2 thin films on ITO and their modification with thin ALD-grown layers.

    PubMed

    Tupala, Jere; Kemell, Marianna; Härkönen, Emma; Ritala, Mikko; Leskelä, Markku

    2012-03-30

    Nanotubular titanium dioxide thin films were prepared by anodization of titanium metal films evaporated on indium tin oxide (ITO) coated glass. A facile method to enhance the adhesion of the titanium film to the ITO glass was developed. An optimum thickness of 550 nm for the evaporated titanium was found to keep the film adhered to ITO during the anodization. The films were further modified by growing amorphous titania, alumina and tantala thin films conformally in the nanotubes by atomic layer deposition (ALD). The optical, electrical and physical properties of the different structures were compared. It was shown that even 5 nm thin layers can modify the properties of the nanotubular titanium dioxide films.

  19. Preparation of regularly structured nanotubular TiO2 thin films on ITO and their modification with thin ALD-grown layers

    NASA Astrophysics Data System (ADS)

    Tupala, Jere; Kemell, Marianna; Härkönen, Emma; Ritala, Mikko; Leskelä, Markku

    2012-03-01

    Nanotubular titanium dioxide thin films were prepared by anodization of titanium metal films evaporated on indium tin oxide (ITO) coated glass. A facile method to enhance the adhesion of the titanium film to the ITO glass was developed. An optimum thickness of 550 nm for the evaporated titanium was found to keep the film adhered to ITO during the anodization. The films were further modified by growing amorphous titania, alumina and tantala thin films conformally in the nanotubes by atomic layer deposition (ALD). The optical, electrical and physical properties of the different structures were compared. It was shown that even 5 nm thin layers can modify the properties of the nanotubular titanium dioxide films.

  20. Nanoparticles Modified ITO Based Biosensor

    NASA Astrophysics Data System (ADS)

    Khan, M. Z. H.

    2016-12-01

    Incorporation of nanomaterials with controlled molecular architecture shows great promise in improving electronic communication between biomolecules and the electrode substrate. In electrochemical applications metal nanoparticles (NPs) modified electrodes have been widely used and are emerging as candidates to develop highly sensitive electrochemical sensors. There has been a growing technological interest in modified indium tin oxide (ITO) electrodes due to their prominent optoelectronic properties and their wide use as a transducing platform. The introduction of NPs into the transducing platform is commonly achieved by their adsorption onto conventional electrode surfaces in various forms, including that of a composite. The aim of this review is to discuss the role of metallic NPs for surface fabrication of ITO thin films leading to detection of specific biomolecules and applications as a biosensor platform.

  1. Nanoparticles Modified ITO Based Biosensor

    NASA Astrophysics Data System (ADS)

    Khan, M. Z. H.

    2017-04-01

    Incorporation of nanomaterials with controlled molecular architecture shows great promise in improving electronic communication between biomolecules and the electrode substrate. In electrochemical applications metal nanoparticles (NPs) modified electrodes have been widely used and are emerging as candidates to develop highly sensitive electrochemical sensors. There has been a growing technological interest in modified indium tin oxide (ITO) electrodes due to their prominent optoelectronic properties and their wide use as a transducing platform. The introduction of NPs into the transducing platform is commonly achieved by their adsorption onto conventional electrode surfaces in various forms, including that of a composite. The aim of this review is to discuss the role of metallic NPs for surface fabrication of ITO thin films leading to detection of specific biomolecules and applications as a biosensor platform.

  2. Effect of modification substrate on the microstructure of hydroxyapatite coating

    NASA Astrophysics Data System (ADS)

    Realpe-Jaramillo, J.; Morales-Morales, J. A.; González-Sánchez, J. A.; Cabanzo, R.; Mejía-Ospino, E.; Rodríguez-Pereira, J.

    2017-01-01

    Bioactive hydroxyapatite (HA) coatings were fabricated by a precipitation, sol-gel and dip-coating method. The effects of the aging time and the base used to adjust pH and substrate materials on the phases and microstructures of HA coatings were studied by field emission scanning electron microscopy FESEM, energy dispersive spectroscopy EDS, X-ray photoelectron spectroscopy XPS, and the vibrations of the phosphate groups were determined by Raman spectroscopy. The results showed that all the films were composed of the phases of TiO2 and HA. With coated titanium substrate with TiO2, the crystallinity of the HA coating increases, the structure became more compact and the Ca/P ratio increased because of the loss of P in the films. The addition of sodium hydroxide (adjusting the pH level to about 10) can increase the HA content in the coating. XPS and EDS results for steel substrate and titanium showed poor calcium content as obtained with a Ca/P ratio of 1.38 and 1.58, respectively, composition is similar to that of natural apatite. However, spectroscopic results suggest the presence of a mixture of hydroxyapatite and octacalcium phosphate. The different substrate materials have a high influence on the microstructure of the separated double films. However, hydroxyapatite nanopowders coatings were obtained using a simple method, with potential biomedical applications.

  3. Effect of Se flux on CuGaSe2 absorbers deposited on ITO-coated SLG substrates by using a three-stage co-evaporation process

    NASA Astrophysics Data System (ADS)

    Yoo, Jinsu; Eo, Young-Joo; Cho, Jun-Sik; Yun, Jae-Ho; Choi, Jang Hun; Kim, Kihwan; Park, Ju Hyung; Kong, Seong Ho

    2016-11-01

    As the key factor for top-cell application in a tandem structure, wide-bandgap chalcopyrite CuGaSe2 (CGS) absorbers were deposited at a thickness of 2 μm on soda-lime glass (SLG) which was coated with radio-frequency sputtered indium-tin-oxide (ITO) films. The semi-transparent CGS absorbers with a bandgap energy of 1.65 eV were grown by using a three-stage co-evaporation process with Cu, Ga, and Se elemental sources. During CGS absorber growth, the composition ratio [Cu]/[Ga] was fixed at about 0.85 and the Se-to-Ga flux ratio P [ Se]/[ Ga] was varied from 22 to 61 by increasing the temperature of the Se source. In this study, the compositional, structural, optical and electrical properties of top-cell CGS absorbers, which absorbed the short wavelength range of the solar spectrums for tandem solar cell application, were investigated as a function of the Se flux. On the basis of our experimental results, the highest CGS solar cell efficiency of 4.7 % in the cell structure described as Al/ZnO:Al/i-ZnO/CdS/CGS/ITO/SLG was demonstrated using a P [ Se]/[ Ga] value of 22.

  4. Surface Modification of Polymer Substrates by Oxygen Ion Irradiation

    SciTech Connect

    Takaoka, G. H.; Ryuto, H.; Araki, R.; Yakushiji, T.

    2008-11-03

    Oxygen cluster ions and/or monomer ions were used for the sputtering and the surface modification of polymers such as polycarbonate (PC) and polyethylene terephthalate (PET). For the case of oxygen cluster ion irradiation, the sputtered depth increased with increase of the acceleration voltage, and the sputtering yield was much larger than that by the monomer ion irradiation. The sputtered particles represented the polymer structure, which indicated that the bond scission by the cluster ion irradiation resulted in an ejection of monomer molecule through the intermolecular collision. On the other hand, for the oxygen monomer ion irradiation, the implanted depth increased with increase of the acceleration voltage, and the bond scission occurred at the deep region through the binary collision with the high energetic ions. Therefore, the sputtering yield for the polymer surfaces decreased, and the sputtering effect became very small. Furthermore, the simultaneous use of oxygen cluster and monomer ions was more effective for oxidation of the PET surfaces rather than the monomer ion irradiation or the cluster ion irradiation. As a result, the contact angle measurement showed that the wettability of the PET surfaces irradiated by the simultaneous use of oxygen cluster and monomer ions was much enhanced.

  5. Patterning of ITO with picosecond lasers

    NASA Astrophysics Data System (ADS)

    Račiukaitis, Gediminas; Brikas, Marijus; Gedvilas, Mindaugas; Darčianovas, Gediminas

    2007-02-01

    Indium-tin oxide (ITO) is the main material for making transparent electrodes in electronic devices and flat panel displays. Laser-direct-write technology has been widely used for patterning ITO. The well defined edges and good electrical isolation at a short separation are required for the modern OLED and RFID devices of high packing density. High repetition rate lasers with a short, picosecond pulse width offer new possibilities for high efficiency structuring of transparent conductors on glass and other substrates. The results of patterning the ITO film on glass with picosecond lasers at various wavelengths are presented. Laser radiation initiated ablation of the material, forming trenches in ITO. Profile of the trenches was analyzed with a phase contrast optical microscope, a stylus type profiler, SEM and AFM. Clean removal of the ITO layer was achieved with the 266 nm radiation when laser fluence was above the threshold at 0.20 J/cm2, while for the 355 nm radiation the threshold was higher, above 0.46 J/cm2. The glass substrate was damaged in the area where the fluence was higher than 1.55 J/cm2. The 532 nm radiation allowed getting well defined trenches, but a lot of residues in the form of dust were generated on the surface. UV radiation at the 266 nm provided the widest working window for ITO ablation without damage of the substrate. Use of UV laser radiation with fluences close to the ablation threshold made it possible to minimize surface contamination and the recast ridge formation during the process.

  6. Substrate and head group modifications for enhanced stability in molecular electronic devices

    NASA Astrophysics Data System (ADS)

    Ferrato, Michael-Anthony

    Poor Self-Assembled Monolayer (SAM) stability is a barrier which impedes the incorporation of molecular layers as functional components in electronic device architectures. Here we investigate the molecular electronic characteristics of two well established approaches to enhancing SAM stability. In Chapter 2 we investigate the electrochemical modification of Au substrates by the underpotential deposition of silver monolayers (AgUPD). In Chapter 3 we study chelating dithiophosphinic acid (DTPA) head groups to anchor SAM molecules to substrates. Based on molecular electronic characterization using EGaIn Tip testbeds, we observed that AgUPD substrates maintained the inherent electronic character of n-alkanethiolate SAMs, but reduced charge transport by almost 1 order of magnitude as compared with the same SAMs on bulk Au substrates. Similar molecular electronic characterization of (diphenyl)dithiophosphinic acid SAMs on Au substrates revealed that the DTPA head group induced a ~3 order of magnitude drop in charge transport as compared with analogous thiophenol SAMs.

  7. Modulus of Elasticity and Thermal Expansion Coefficient of ITO Film

    SciTech Connect

    Carter, Austin D.; Elhadj, S.

    2016-06-24

    The purpose of this experiment was to determine the modulus of elasticity (E) and thermal expansion coefficient (α) of RF sputtered Indium Tin Oxide (ITO) as a function of temperature (T), and to collect ITO film stress data. In order to accomplish that goal, the Toho FLX-2320-S thin film stress measurement machine was used to collect both single stress and stress-temperature data for ITO coated fused silica and sapphire substrates. The stress measurement function of the FLX-2320-S cannot be used to calculate the elastic modulus of the film because the Stoney formula incorporates the elastic modulus of the substrate, rather than of the film itself.

  8. Protein adsorption to graphene surfaces controlled by chemical modification of the substrate surfaces.

    PubMed

    Kamiya, Yasutaka; Yamazaki, Kenji; Ogino, Toshio

    2014-10-01

    We have investigated effects of the support substrate surfaces on properties of the attached graphene flakes by observing protein adsorption to the graphene surfaces on SiO2/Si substrates that are modified with self-assembled monolayers to control their hydrophilicity. Using atomic force microscopy operated in aqueous environment, we found that high-density clusters of agglomerated avidin molecules form on the graphene flakes in the areas supported by a hydrophobic substrate surface, whereas very low density of large avidin clusters form at the edge of graphene flakes in the area supported by a hydrophilic surface. These results demonstrate that hydrophilicity of the support surface affects hydrophilicity of the graphene surface also in aqueous environment and that surface modification of the support substrate is a useful technique to control protein adsorption phenomena on graphene surfaces for realization of high sensitive graphene biosensors.

  9. SERS-based ultrasensitive detection of organophosphorus nerve agents via substrate's surface modification.

    PubMed

    Zhao, Qian; Liu, Guangqiang; Zhang, Hongwen; Zhou, Fei; Li, Yue; Cai, Weiping

    2017-02-15

    Highly efficient detection of the organicphosphor nerve agents such as sarin and soman, based on surface enhanced Raman scattering (SERS) effect, has been in challenge due to their weak adsorption property on coin metals. In this paper, a new strategy is presented to achieve the SERS-based ultrasensitive detection of sarin-simulated agent methanephosphonic acid (MPA) via the surface modification of SERS-substrates. The Au-coated Si nanocone array is surface-modified with 2-aminoethanethiol and used as SERS-substrate for detection of MPA. It has been shown that the modified substrate could preferentially capture MPA molecules in the solution with coupling agent and induce amidation reaction. The reaction products are still bound or anchor on the substrate's surface. The MPA molecules can thus be detected by Raman spectral measurement of the solution-soaked SERS-substrate. The minimum detection level is down to ∼1ppb. The Raman peak intensity versus the MPA concentration is subject to a linear double logarithmic relation from ∼1ppb to ∼1000ppm, which is attributed to Freundlich adsorption of MPA on the surface-modified SERS substrate. This study provides a new way for the highly efficient SERS-based detection of the organophosphorus nerve agents and some other target molecules weakly interacted with metal substrates.

  10. Effects of different substrate surface modifications on the epitaxial ZnO/Si

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Jin, Changlian; Zhan, Huahan; Chen, Xiaohang; Xu, Fuchun; Zhou, Yinghui; Wang, Huiqiong; Kang, Junyong

    2013-09-01

    To produce high quality ZnO/Si for the applications in short wavelength optoelectronic devices, the effects of different silicon surface modifications on the overgrown ZnO thin film were investigated. Samples were grown by a plasma assistant molecular beam epitaxy at room temperature, avoiding the oxidation of the Si surface and the thermal stress caused by difference of the thermal expansion coefficients between ZnO and silicon. Different modifications on the Si(100) substrate surface including nitridation, oxidation, and depositions of Mg and Zn, were employed. The effects on the overgrown ZnO layers and the interlayer SiOx were investigated by atomic force microscopy, photoluminescence, X-ray diffraction and auger depth electron spectroscopy. All the modifications were effective in different degrees at reducing the SiOx amorphous layer. However, different mechanisms resulted in distinct performance in crystal structure and optical property.

  11. Electrochemical characterization of organosilane-functionalized nanostructured ITO surfaces

    NASA Astrophysics Data System (ADS)

    Pruna, R.; Palacio, F.; López, M.; Pérez, J.; Mir, M.; Blázquez, O.; Hernández, S.; Garrido, B.

    2016-08-01

    The electroactivity of nanostructured indium tin oxide (ITO) has been investigated for its further use in applications such as sensing biological compounds by the analysis of redox active molecules. ITO films were fabricated by using electron beam evaporation at different substrate temperatures and subsequently annealed for promoting their crystallization. The morphology of the deposited material was monitored by scanning electron microscopy, confirming the deposition of either thin films or nanowires, depending on the substrate temperature. Electrochemical surface characterization revealed a 45 % increase in the electroactive surface area of nanostructured ITO with respect to thin films, one third lower than the geometrical surface area variation determined by atomic force microscopy. ITO surfaces were functionalized with a model organic molecule known as 6-(ferrocenyl)hexanethiol. The chemical attachment was done by means of a glycidoxy compound containing a reactive epoxy group, the so-called 3-glycidoxypropyltrimethoxy-silane. ITO functionalization was useful for determining the benefits of nanostructuration on the surface coverage of active molecules. Compared to ITO thin films, an increase in the total peak height of 140 % was observed for as-deposited nanostructured electrodes, whereas the same measurement for annealed electrodes resulted in an increase of more than 400 %. These preliminary results demonstrate the ability of nanostructured ITO to increase the surface-to-volume ratio, conductivity and surface area functionalization, features that highly benefit the performance of biosensors.

  12. MOCVD growth of GaN on Si through novel substrate modification techniques

    NASA Astrophysics Data System (ADS)

    Gagnon, Jarod C.

    GaN is a semiconductor material with great potential for use in high power electronics and optoelectronics due to the high electron mobility, high breakdown voltage, high thermal stability, and large direct bandgap of GaN. Si is a desirable substrate material for GaN heteroepitaxy due to the low cost of production, large wafer sizes available, and current widespread use in the electronics industry. The growth of GaN/Si devices suffers from the lattice and CTE mismatches between GaN and Si and therefore multiple methods of strain reduction have been employed to counter these effects. In this work we presented two novel methods of substrate modification to promote the growth of device quality GaN on Si. Initial work focused on the implantation of AlN/Si(111) substrates with N+ ions below the AlN/Si(111) interface. A reduction in the initial compressive stress in GaN films as well as the degree of tensile stress generation during growth was observed on implanted samples. Optical microscopy of the GaN surfaces showed reduced channeling crack density on implanted substrates. Transmission electron microscopy (TEM) studies showed a disordered layer in the Si substrate at the implantation depth which consisted of a mixture of polycrystalline and amorphous Si. Evidence was provided to suggest that the disordered layer at the implantation depth was acting as a compliant layer which decoupled the GaN film from the bulk Si substrate and partially accommodated the tensile stress formed during growth and cooling. A reduction in threading dislocation (TD) density on ion implanted substrates was also observed. Additional studies showed that by increasing the lateral size of AlN islands, the tensile growth stress and TD density in GaN films on ion implanted substrates could be further reduced. XRD studies showed an expansion of the AlN lattice on implanted substrates with larger lateral island sizes. The final tensile growth stress of films on implanted substrates was further

  13. Surface modification of several dental substrates by non-thermal, atmospheric plasma brush

    PubMed Central

    Chen, Mingsheng; Zhang, Ying; Driver, M. Sky; Caruso, Anthony N.; Yu, Qingsong; Wang, Yong

    2013-01-01

    Objective The purpose of this study was to reveal the effectiveness of non-thermal atmospheric plasma brush in surface wettability and modification of four dental substrates. Methods Specimens of dental substrates including dentin, enamel, and two composites Filtek Z250, Filtek LS Silorane were prepared (~2 mm thick, ~10 mm diameter). The prepared surfaces were treated for 5–45 s with a non-thermal atmospheric plasma brush working at temperatures from 36 to 38 °C. The plasma-treatment effects on these surfaces were studied with contact-angle measurement, X-ray photoemission spectroscopy (XPS) and scanning electron microscopy (SEM). Results The non-thermal atmospheric argon plasma brush was very efficient in improving the surface hydrophilicity of four substrates studied. The results indicated that water contact angle values decreased considerably after only 5 s plasma treatment of all these substrates. After 30 s treatment, the values were further reduced to <5°, which was close to a value for super hydrophilic surfaces. XPS analysis indicated that the percent of elements associated with mineral in dentin/enamel or fillers in the composites increased. In addition, the percent of carbon (%C) decreased while %O increased for all four substrates. As a result, the O/C ratio increased dramatically, suggesting that new oxygen-containing polar moieties were formed on the surfaces after plasma treatment. SEM surface images indicated that no significant morphology change was induced on these dental substrates after exposure to plasmas. Significance Without affecting the bulk properties, a super-hydrophilic surface could be easily achieved by the plasma brush treatment regardless of original hydrophilicity/hydrophobicity of dental substrates tested. PMID:23755823

  14. Highly ordered, accessible and nanocrystalline mesoporous TiO₂ thin films on transparent conductive substrates.

    PubMed

    Violi, Ianina L; Perez, M Dolores; Fuertes, M Cecilia; Soler-Illia, Galo J A A

    2012-08-01

    Highly porous (V(mesopore) = 25-50%) and ordered mesoporous titania thin films (MTTF) were prepared on ITO (indium tin oxide)-covered glass by a fast two-step method. The effects of substrate surface modification and thermal treatment on pore order, accessibility and crystallinity of the MTTF were systematically studied for MTTF deposited onto bare and titania-modified ITO. MTTF exposed briefly to 550 °C resulted in highly ordered films with grid-like structures, enlarged pore size, and increased accessible pore volume when prepared onto the modified ITO substrate. Mesostructure collapse and no significant change in pore volume were observed for MTTF deposited on bare ITO substrates. Highly crystalline anatase was obtained for MTTF prepared on the modified-ITO treated at high temperatures, establishing the relationship between grid-like structures and titania crystallization. Photocatalytic activity was maximized for samples with increased crystallization and high accessible pore volume. In this manner, a simple way of designing materials with optimized characteristics for optoelectronic applications was achieved through the modification of the ITO surface and a controlled thermal treatment.

  15. Surface modification of cellulosic substrates via atmospheric pressure plasma polymerization of acrylic acid: Structure and properties

    NASA Astrophysics Data System (ADS)

    Garcia-Torres, Jose; Sylla, Dioulde; Molina, Laura; Crespo, Eulalia; Mota, Jordi; Bautista, Llorenç

    2014-06-01

    Surface chemical modification of cellulose-based substrates has been carried out by atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD) of acrylic acid. The structure/properties relationship of the samples was studied as a function of the plasma experimental conditions. Acrylic acid monomer/helium ratio and treatment speed clearly influences the wettability properties of the paper substrate: advancing contact angle values were reduced to the half if compare to non-treated paper. Surface morphology of the films did not greatly vary at short polymerization times but fibers were covered by a poly(acrylic acid) film at longer times. FTIR and XPS techniques allowed detecting the retention of carboxylic acid groups/moieties. The possibility to quickly design architectures with tunable carboxylic functions by modifying the plasma processing parameters is shown.

  16. ZnO nanostructures directly grown on paper and bacterial cellulose substrates without any surface modification layer.

    PubMed

    Costa, Saionara V; Gonçalves, Agnaldo S; Zaguete, Maria A; Mazon, Talita; Nogueira, Ana F

    2013-09-21

    In this report, hierarchical ZnO nano- and microstructures were directly grown for the first time on a bacterial cellulose substrate and on two additional different papers by hydrothermal synthesis without any surface modification layer. Compactness and smoothness of the substrates are two important parameters that allow the growth of oriented structures.

  17. Enhancing the Properties of Carbon and Gold Substrates by Surface Modification

    SciTech Connect

    Harnisch, Jennifer Anne

    2001-01-01

    The properties of both carbon and gold substrates are easily affected by the judicious choice of a surface modification protocol. Several such processes for altering surface composition have been published in literature. The research presented in this thesis primarily focuses on the development of on-column methods to modify carbon stationary phases used in electrochemically modulated liquid chromatography (EMLC). To this end, both porous graphitic carbon (PGC) and glassy carbon (GC) particles have been modified on-column by the electroreduction of arenediazonium salts and the oxidation of arylacetate anions (the Kolbe reaction). Once modified, the carbon stationary phases show enhanced chromatographic performance both in conventional liquid chromatographic columns and EMLC columns. Additionally, one may also exploit the creation of aryl films to by electroreduction of arenediazonium salts in the creation of nanostructured materials. The formation of mercaptobenzene film on the surface of a GC electrode provides a linking platform for the chemisorption of gold nanoparticles. After deposition of nanoparticles, the surface chemistry of the gold can be further altered by self-assembled monolayer (SAM) formation via the chemisorption of a second thiol species. Finally, the properties of gold films can be altered such that they display carbon-like behavior through the formation of benzenehexathiol (BHT) SAMs. BHT chemisorbs to the gold surface in a previously unprecedented planar fashion. Carbon and gold substrates can be chemically altered by several methodologies resulting in new surface properties. The development of modification protocols and their application in the analytical arena is considered herein.

  18. Fabrication of robust hydrogel coatings on polydimethylsiloxane substrates using micropillar anchor structures with chemical surface modification.

    PubMed

    Zhang, Hongbin; Bian, Chao; Jackson, John K; Khademolhosseini, Farzad; Burt, Helen M; Chiao, Mu

    2014-06-25

    A durable hydrophilic and protein-resistant surface of polydimethylsiloxane (PDMS) based devices is desirable in many biomedical applications such as implantable and microfluidic devices. This paper describes a stable antifouling hydrogel coating on PDMS surfaces. The coating method combines chemical modification and surface microstructure fabrication of PDMS substrates. Three-(trimethoxysilyl)propyl methacrylates containing C═C groups were used to modify PDMS surfaces with micropillar array structures fabricated by a replica molding method. The micropillar structures increase the surface area of PDMS surfaces, which facilitates secure bonding with a hydrogel coating compared to flat PMDS surfaces. The adhesion properties of the hydrogel coating on PDMS substrates were characterized using bending, stretching and water immersion tests. Long-term hydrophilic stability (maintaining a contact angle of 55° for a month) and a low protein adsorption property (35 ng/cm(2) of adsorbed BSA-FITC) of the hydrogel coated PDMS were demonstrated. This coating method is suitable for PDMS modification with most crosslinkable polymers containing C═C groups, which can be useful for improving the anti-biofouling performance of PDMS-based biomedical microdevices.

  19. Nanoscale patterning of a self-assembled monolayer by modification of the molecule–substrate bond

    PubMed Central

    Shen, Cai

    2014-01-01

    Summary The intercalation of Cu at the interface of a self-assembled monolayer (SAM) and a Au(111)/mica substrate by underpotential deposition (UPD) is studied as a means of high resolution patterning. A SAM of 2-(4'-methylbiphenyl-4-yl)ethanethiol (BP2) prepared in a structural phase that renders the Au substrate completely passive against Cu-UPD, is patterned by modification with the tip of a scanning tunneling microscope. The tip-induced defects act as nucleation sites for Cu-UPD. The lateral diffusion of the metal at the SAM–substrate interface and, thus, the pattern dimensions are controlled by the deposition time. Patterning down to the sub-20 nm range is demonstrated. The difference in strength between the S–Au and S–Cu bond is harnessed to develop the latent Cu-UPD image into a patterned binary SAM. Demonstrated by the exchange of BP2 by adamantanethiol (AdSH) this is accomplished by a sequence of reductive desorption of BP2 in Cu free areas followed by adsorption of AdSH. The appearance of Au adatom islands upon the thiol exchange suggests that the interfacial structures of BP2 and AdSH SAMs are different. PMID:24778947

  20. Nanoscale patterning of a self-assembled monolayer by modification of the molecule-substrate bond.

    PubMed

    Shen, Cai; Buck, Manfred

    2014-01-01

    The intercalation of Cu at the interface of a self-assembled monolayer (SAM) and a Au(111)/mica substrate by underpotential deposition (UPD) is studied as a means of high resolution patterning. A SAM of 2-(4'-methylbiphenyl-4-yl)ethanethiol (BP2) prepared in a structural phase that renders the Au substrate completely passive against Cu-UPD, is patterned by modification with the tip of a scanning tunneling microscope. The tip-induced defects act as nucleation sites for Cu-UPD. The lateral diffusion of the metal at the SAM-substrate interface and, thus, the pattern dimensions are controlled by the deposition time. Patterning down to the sub-20 nm range is demonstrated. The difference in strength between the S-Au and S-Cu bond is harnessed to develop the latent Cu-UPD image into a patterned binary SAM. Demonstrated by the exchange of BP2 by adamantanethiol (AdSH) this is accomplished by a sequence of reductive desorption of BP2 in Cu free areas followed by adsorption of AdSH. The appearance of Au adatom islands upon the thiol exchange suggests that the interfacial structures of BP2 and AdSH SAMs are different.

  1. ITOS/space shuttle study

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The results are reported of a study to explore the potential cost reductions in the operational ITOS weather satellite program as a consequence of shuttle/bug availability for satellite placement and retrieval, and satellite servicing and maintenance. The study program was divided into shuttle impact on equipment and testing costs, and shuttle impact on overall future ITOS operational program costs, and shuttle impact on configuration. It is concluded that savings in recurring spacecraft costs can be realized in the 1978 ITOS program, if a space shuttle is utilized.

  2. Structural modification of herboxidiene by substrate-flexible cytochrome P450 and glycosyltransferase.

    PubMed

    Jha, Amit Kumar; Dhakal, Dipesh; Van, Pham Thi Thuy; Pokhrel, Anaya Raj; Yamaguchi, Tokutaro; Jung, Hye Jin; Yoon, Yeo Joon; Sohng, Jae Kyung

    2015-04-01

    Herboxidiene is a natural product produced by Streptomyces chromofuscus exhibiting herbicidal activity as well as antitumor properties. Using different substrate-flexible cytochrome P450s and glycosyltransferase, different novel derivatives of herboxidiene were generated with structural modifications by hydroxylation or epoxidation or conjugation with a glucose moiety. Moreover, two isomers of herboxidiene containing extra tetrahydrofuran or tetrahydropyran moiety in addition to the existing tetrahydropyran moiety were characterized. The hydroxylated products for both of these compounds were also isolated and characterized from S. chromofuscus PikC harboring pikC from the pikromycin gene cluster of Streptomyces venezuelae and S. chromofuscus EryF harboring eryF from the erythromycin gene cluster of Saccharopolyspora erythraea. The compounds generated were characterized by high-resolution quadrupole-time-of-flight electrospray ionization mass spectrometry (HR-QTOF-ESI/MS) and (1)H- and (13)C-nuclear magnetic resonance (NMR) analyses. The evaluation of antibacterial activity against three Gram-positive bacteria, Micrococcus luteus, Bacillus subtilis, and Staphylococcus aureus, indicated that modification resulted in a transition from anticancer to antibacterial potency.

  3. Surface modification of polymeric substrates by plasma-based ion implantation

    NASA Astrophysics Data System (ADS)

    Okuji, S.; Sekiya, M.; Nakabayashi, M.; Endo, H.; Sakudo, N.; Nagai, K.

    2006-01-01

    Plasma-based ion implantation (PBII) as a tool for polymer modification is studied. Polymeric films have good performances for flexible use, such as food packaging or electronic devices. Compared with inorganic rigid materials, polymers generally have large permeability for gases and moisture, which causes packaged contents and devices to degrade. In order to add a barrier function, surface of polymeric films are modified by PBII. One of the advantageous features of this method over deposition is that the modified surface does not have peeling problem. Besides, micro-cracks due to mechanical stress in the modified layer can be decreased. From the standpoint of mass production, conventional ion implantation that needs low-pressure environment of less than 10-3 Pa is not suitable for continuous large-area processing, while PBII works at rather higher pressure of several Pa. In terms of issues mentioned above, PBII is one of the most expected techniques for modification on flexible substrates. However, the mechanism how the barrier function appears by ion implantation is not well explained so far. In this study, various kinds of polymeric films, including polyethyleneterephthalate (PET), are modified by PBII and their barrier characteristics that depend on the ion dose are evaluated. In order to investigate correlations of the barrier function with implanted ions, modified surface is analyzed with X-ray photoelectron spectroscopy (XPS). It is assumed that the diffusion and sorption coefficients are changed by ion implantation, resulting in higher barrier function.

  4. Roll-to-Roll sputtered ITO/Cu/ITO multilayer electrode for flexible, transparent thin film heaters and electrochromic applications

    PubMed Central

    Park, Sung-Hyun; Lee, Sang-Mok; Ko, Eun-Hye; Kim, Tae-Ho; Nah, Yoon-Chae; Lee, Sang-Jin; Lee, Jae Heung; Kim, Han-Ki

    2016-01-01

    We fabricate high-performance, flexible, transparent electrochromic (EC) films and thin film heaters (TFHs) on an ITO/Cu/ITO (ICI) multilayer electrode prepared by continuous roll-to-roll (RTR) sputtering of ITO and Cu targets. The RTR-sputtered ICI multilayer on a 700 mm wide PET substrate at room temperature exhibits a sheet resistance of 11.8 Ω/square and optical transmittance of 73.9%, which are acceptable for the fabrication of flexible and transparent EC films and TFHs. The effect of the Cu interlayer thickness on the electrical and optical properties of the ICI multilayer was investigated in detail. The bending and cycling fatigue tests demonstrate that the RTR-sputtered ICI multilayer was more flexible than a single ITO film because of high strain failure of the Cu interlayer. The flexible and transparent EC films and TFHs fabricated on the ICI electrode show better performances than reference EC films and TFHs with a single ITO electrode. Therefore, the RTR-sputtered ICI multilayer is the best substitute for the conventional ITO film electrode in order to realize flexible, transparent, cost-effective and large-area EC devices and TFHs that can be used as flexible and smart windows. PMID:27653830

  5. Roll-to-Roll sputtered ITO/Cu/ITO multilayer electrode for flexible, transparent thin film heaters and electrochromic applications

    NASA Astrophysics Data System (ADS)

    Park, Sung-Hyun; Lee, Sang-Mok; Ko, Eun-Hye; Kim, Tae-Ho; Nah, Yoon-Chae; Lee, Sang-Jin; Lee, Jae Heung; Kim, Han-Ki

    2016-09-01

    We fabricate high-performance, flexible, transparent electrochromic (EC) films and thin film heaters (TFHs) on an ITO/Cu/ITO (ICI) multilayer electrode prepared by continuous roll-to-roll (RTR) sputtering of ITO and Cu targets. The RTR-sputtered ICI multilayer on a 700 mm wide PET substrate at room temperature exhibits a sheet resistance of 11.8 Ω/square and optical transmittance of 73.9%, which are acceptable for the fabrication of flexible and transparent EC films and TFHs. The effect of the Cu interlayer thickness on the electrical and optical properties of the ICI multilayer was investigated in detail. The bending and cycling fatigue tests demonstrate that the RTR-sputtered ICI multilayer was more flexible than a single ITO film because of high strain failure of the Cu interlayer. The flexible and transparent EC films and TFHs fabricated on the ICI electrode show better performances than reference EC films and TFHs with a single ITO electrode. Therefore, the RTR-sputtered ICI multilayer is the best substitute for the conventional ITO film electrode in order to realize flexible, transparent, cost-effective and large-area EC devices and TFHs that can be used as flexible and smart windows.

  6. Investigation of restriction-modification enzymes from M. varians RFL19 with a new type of specificity toward modification of substrate.

    PubMed Central

    Butkus, V; Klimasauskas, S; Kersulyte, D; Vaitkevicius, D; Lebionka, A; Janulaitis, A

    1985-01-01

    The characterization of MvaI restriction-modification enzymes, isolated from Micrococcus varians RFL19, is reported. Both enzymes recognize the 5'CC decreases (A/T)GG nucleotide sequence. The endonuclease cleaves the sequence at the position indicated by the arrow, whereas the methylase modifies the internal cytosine, yielding N4-methylcytosine. This type of modification protects the substrate from R.MvaI cleavage. 5-Methylcytosine in the same position of the recognition sequence does not protect the substrate from R.MvaI cleavage. R.MvaI proved to be the first example of a restriction endonuclease differentiating the position of the methyl group in the heterocyclic ring of cytosine, located in the same site of the recognition sequence. M.MvaI modifies DNA dcm+ in vitro yielding N4,5-dimethylcytosine. N4-methylcytosine cannot be differentiated from cytosine using the Maxam-Gilbert DNA sequencing procedure. Images PMID:2994011

  7. Transparent Conductive ITO/Ag/ITO Electrode Deposited at Room Temperature for Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Kim, Jun Ho; Kang, Tae-Woon; Kwon, Sung-Nam; Na, Seok-In; Yoo, Young-Zo; Im, Hyeong-Seop; Seong, Tae-Yeon

    2017-01-01

    We investigated the optical and electrical properties of room-temperature-deposited indium-tin-oxide (ITO)/Ag (19 nm)/ITO multilayer films as a function of ITO layer thickness. The optical and electrical properties of the ITO/Ag/ITO films were compared with those of high-temperature-deposited ITO-only films for use as an anode in organic solar cells (OSCs). The ITO/Ag/ITO multilayer films had sheet resistances in the range 5.40-5.78 Ω/sq, while the ITO-only film showed 14.18 Ω/sq. The carrier concentration of the ITO/Ag/ITO films gradually decreased from 2.01 × 1022 to 7.20 × 1021 cm-3 as the ITO thickness increased from 17 nm to 83 nm. At 530 nm, the transmittance of the ITO/Ag/ITO (50 nm/19 nm/50 nm) films was 90%, while that of the ITO-only film gave 96.5%. The multilayer film had a smooth surface with a root mean square (RMS) roughness of 0.49 nm. Poly (3-hexylthiophene) (P3HT):[6,6]-phenyl-C61 butyric acid methylester (PCBM) bulk heterojunction (BHJ)-based OSCs fabricated with the ITO/Ag/ITO (50 nm/19 nm/50 nm) film showed a power conversion efficiency (PCE) (2.84%) comparable to that of OSCs with a conventional ITO-only anode (3.48%).

  8. Rapid fabrication of a silicon modification layer on silicon carbide substrate.

    PubMed

    Bai, Yang; Li, Longxiang; Xue, Donglin; Zhang, Xuejun

    2016-08-01

    We develop a kind of magnetorheological (MR) polishing fluid for the fabrication of a silicon modification layer on a silicon carbide substrate based on chemical theory and actual polishing requirements. The effect of abrasive concentration in MR polishing fluid on material removal rate and removal function shape is investigated. We conclude that material removal rate will increase and tends to peak value as the abrasive concentration increases to 0.3 vol. %, and the removal function profile will become steep, which is a disadvantage to surface frequency error removal at the same time. The removal function stability is also studied and the results show that the prepared MR polishing fluid can satisfy actual fabrication requirements. An aspheric reflective mirror of silicon carbide modified by silicon is well polished by combining magnetorheological finishing (MRF) using two types of MR polishing fluid and computer controlled optical surfacing (CCOS) processes. The surface accuracy root mean square (RMS) is improved from 0.087λ(λ=632.8  nm) initially to 0.020λ(λ=632.8  nm) in 5.5 h total and the tool marks resulting from MRF are negligible. The PSD analysis results also shows that the final surface is uniformly polished.

  9. Optical properties of ITO nanocoatings for photovoltaic and energy building applications

    NASA Astrophysics Data System (ADS)

    Kaplani, E.; Kaplanis, S.; Panagiotaras, D.; Stathatos, E.

    2014-10-01

    Targeting energy savings in buildings, photovoltaics and other sectors, significant research activity is nowadays focused on the production of spectral selective nanocoatings. In the present study an ITO coating on glass substrate is prepared from ITO powder, characterized and analysed. The spectral transmittance and reflectance of the ITO coated glass and of two other commercially developed ITO coatings on glass substrate were measured and compared. Furthermore, a simulation algorithm was developed to determine the optical properties of the ITO coatings in the visible, solar and near infrared regions in order to assess the impact of the ITO coatings in the energy performance of buildings, and particularly the application in smart windows. In addition, the current density produced by a PV assuming each of the ITO coated glass served as a cover was computed, in order to assess their effect in PV performance. The preliminary ITO coating prepared and the two other coatings exhibit different optical properties and, thus, have different impact on energy performance. The analysis assists in a better understanding of the desired optical properties of nanocoatings for improved energy performance in PV and buildings.

  10. Enhanced superhydrophilicity and thermal stability of ITO surface with patterned ceria coatings

    NASA Astrophysics Data System (ADS)

    Xue, Mingshan; Peng, Na; Li, Changquan; Ou, Junfei; Wang, Fajun; Li, Wen

    2015-02-01

    Surface wettability of solid materials is significant for both fundamental research and engineering applications. Compared with most existing fabrication methods of superhydrophilic surfaces by UV exposure or chemical modification, in this work, a superhydrophilic ceria coating on ITO substrate is developed by a fast, simple one-step method. It is found that the superhydrophilicity of ceria coatings is strongly dependent on both the patterned microstructures benefiting the capillary effect and the peculiar chemical composition of ceria inducing numerous oxygen vacancies and large surface free energy. Owing to the inherent physical stability of ceria, such a superhydrophilic ceria coating exhibits an excellently thermal stability at both room temperature and higher temperature. These results open up new avenues for the underlying applications of superhydrophilic coatings, such as heat transfer/dissipation.

  11. Towards promising modification of GeSi nanostructures via self-assembly on miscut Si(001) substrates

    NASA Astrophysics Data System (ADS)

    Zhou, Tong; Zhong, Zhenyang

    2016-03-01

    Self-assembled GeSi nanostructures on miscut Si(001) substrates are studied systematically with regard to the miscut angle and azimuth, the amount of Ge and the growth temperature. The comprehensive dependence of the spatial arrangement, which can exhibit one- and two-dimensional (1D and 2D) ordering, as well as the shape and density, of GeSi nanostructures on the miscut angle is observed. The orientation and side-walls of the 1D ordered in-plane GeSi nanowires on miscut Si(001) substrates are intimately associated with the miscut azimuth towards the <110> or <010> directions. Furthermore, the unique evolution of the GeSi nanostructures with the amount of Ge and the growth temperature on miscut Si (001) substrates towards the <010> direction is discovered. Such promising features of self-assembled GeSi nanostructures on miscut Si (001) substrates are explained in terms of the thermodynamics and growth kinetics, which are both affected significantly by the substrate vicinality. These results demonstrate that the miscut substrates offer a promising degree of freedom for the feasible modification of self-assembled nanostructures.

  12. ITO/ATO bilayer transparent electrodes with enhanced light scattering, thermal stability and electrical conductance

    NASA Astrophysics Data System (ADS)

    Guillén, C.; Montero, J.; Herrero, J.

    2016-10-01

    Transparent electrodes based on In2O3:Sn (ITO) and SnO2:Sb (ATO) thin films have been deposited by sputtering at room temperature on soda lime glass (SLG) substrates. The preparation conditions were adjusted to obtain 250 nm-thick ITO layers with high conductivity and textured ATO coatings with various thicknesses from 80 to 200 nm. These ITO and ATO films have been combined to enhance the optical scattering and the electrical conductivity of the bilayer electrodes. Besides, a suitable ATO coating can prevent the oxidation of the ITO underlayer, thus increasing the stability of the overall electrical performance. With this purpose the structure, morphology, optical and electrical properties have been analysed comparatively for SLG/ITO, SLG/ATO and SLG/ITO/ATO samples after heating in air at 500 °C, studying the influence of the ATO layer thickness on the light scattering and thermal stability of the electrodes. In this way, a minimum sheet resistance of 8 Ω/sq has been achieved with a 120 nm-thick ATO film deposited on the 250 nm-thick ITO layer; such stacked electrode has visible transmittance near 80% and average haze HT = 10%, showing superior stability, light scattering and electrical performance than the isolated ITO and ATO films.

  13. Photocatalytic degradation of methyl orange over ITO/Cds/ZnO interface composite films.

    PubMed

    Wei, Shouqiang; Shao, Zhongcai; Lu, Xudong; Liu, Ying; Cao, Linlin; He, Yan

    2009-01-01

    ITO/CdS/ZnO interface composite films were successfully prepared by subsequent electrodeposition of CdS and ZnO onto indium tin oxide (ITO) glass substrates. The obtained ITO/CdS/ZnO composite films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV-Vis spectroscopy. The photocatalytic activity of ITO/CdS/ZnO composite films were investigated using methyl orange (MO) as a model organic compound under UV light irradiation. The influence of operating parameters on MO degradation including initial concentration of MO, pH value of solution, and inorganic anion species over the composite films were examined. A blue shift of absorption threshold was observed for the ITO/CdS/ZnO film in comparison with ITO/ZnO film. ITO/CdS/ZnO composite films prepared under specific conditions showed a higher photocatalytic activity than that of ITO/ZnO films. It was also found that the photocatalytic degradation of MO on the composite films followed pseudo-first order kinetics.

  14. Facile modification of silica substrates provides a platform for direct-writing surface click chemistry.

    PubMed

    Oberhansl, Sabine; Hirtz, Michael; Lagunas, Anna; Eritja, Ramon; Martinez, Elena; Fuchs, Harald; Samitier, Josep

    2012-02-20

    Please click here: a facile two-step functionalization strategy for silicon oxide-based substrates generates a stable platform for surface click chemistry via direct writing. The suitability of the obtained substrates is proven by patterning with two different direct-writing techniques and three different molecules.

  15. Comparative study on gamma irradiation and cold plasma pretreatment for a cellulosic substrate modification with phenolic compounds

    NASA Astrophysics Data System (ADS)

    Irimia, Anamaria; Ioanid, Ghiocel Emil; Zaharescu, Traian; Coroabă, Adina; Doroftei, Florica; Safrany, Agnes; Vasile, Cornelia

    2017-01-01

    The efficiency of the activation of the cellulose/chitin mix substrate by cold plasma or γ-radiation exposure in order to modify it with bioactive compounds was studied. The eugenol or vegetable oils such as grape seed oil and rosehip seed oil have been grafted onto activated substrate. The examination of modified cellulose/chitin mix substrate by ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy and scanning electron microscopy confirms that the structural and morphological changes took place in both cases. The grafting degrees of the surface layer estimated from XPS data varied from 31.1% to 58.7% for air cold plasma activation and from 9.7% to 22.8% for γ-irradiation treatment. They depend both on bioactive compound used and procedure of substrate activation. Higher grafting degree are obtain by using vegetable oils than in the case of modification with eugenol and the air cold plasma activation seems to be much efficient than γ-irradiation. By grafting the polymeric substrate with bioactive compounds, antimicrobial and antioxidant properties have been conferred. Such materials can be considered promising for food packaging applications and medical textiles and also the applied procedures are environmental friendly ones.

  16. Modification of the surface state of rough substrates by two different varnishes and influence on the reflected light

    NASA Astrophysics Data System (ADS)

    Elias, Mady; René de la Rie, E.; Delaney, John K.; Charron, Eric; Morales, Kathryn M.

    2006-10-01

    Modification of the visual appearance when a rough surface is covered by a varnish is mostly attributed to the levelling of the substrate surface, which depends on the molecular weight of the varnish. The topography of varnished surfaces, however, has never been measured directly. Surfaces of varnishes applied over glass substrates of varying roughness were studied, therefore, using mechanical profilometry. Two different varnishes made with a low and a high molecular weight resin were studied. Both varnishes lower the r.m.s. roughness of the substrates and filter the high spatial frequencies. These results are amplified for the varnish containing the low molecular weight resin. The light reflected by the varnished samples is modelled from these topographical data. Its angular distribution, calculated from the probability density of slopes is presented, taking into account separately the air/varnish and the varnish/substrate interfaces. These analyses are presented in a back-scattering configuration. They show that varnishing significantly reduces the angular width of the reflected light and that this effect is magnified for the low molecular weight resin. Modelling furthermore shows that the influence of the roughness of the varnish/substrate interface is negligible in the total reflected light.

  17. Film Properties and Polycrystallization of Organic Dyes on ITOs with Surface Treatment for Organic Light-Emitting Diodes

    NASA Astrophysics Data System (ADS)

    Iwama, Yuki; Mori, Tatsuo; Mizutani, Teruyoshi

    ITO(Indium-Tin-Oxide) has been now widely used as the transparent anode for organic light-emitting devices(OLEDs). We used various methods of ITO surface treatment and examined the effects of them by measuring contact angle and calculating surface energy. We also prepared OLEDs with ITO treated by each method, and estimated their characteristics. The surface of ITO treated by UV-O3 or O2-plasma was more hydrophilic than that treated by only organic rinse or no treatment, and consequently the characteristic of the OLED was improved. We suppose these treatments affect the hole injection from ITO into organic layer, due to ionization potential or surface cleanness. We also investigated time degradation of NPD films on the ITO substrates. The films deposited with high deposition rate porycrystallized faster.

  18. Atom-scale covalent electrochemical modification of single-layer graphene on SiC substrates by diaryliodonium salts

    DOE PAGES

    Gearba, Raluca I.; Mueller, Kory M.; Veneman, Peter A.; ...

    2015-05-09

    Owing to its high conductivity, graphene holds promise as an electrode for energy devices such as batteries and photovoltaics. However, to this end, the work function and doping levels in graphene need to be precisely tuned. One promising route for modifying graphene’s electronic properties is via controlled covalent electrochemical grafting of molecules. We show that by employing diaryliodonium salts instead of the commonly used diazonium salts, spontaneous functionalization is avoided. This then allows for precise tuning of the grafting density. Moreover, by employing bis(4-nitrophenyl)iodonium(III) tetrafluoroborate (DNP) salt calibration curves, the surface functionalization density (coverage) of glassy carbon was controlled usingmore » cyclic voltammetry in varying salt concentrations. These electro-grafting conditions and calibration curves translated directly over to modifying single layer epitaxial graphene substrates (grown on insulating 6H-SiC (0 0 0 1)). In addition to quantifying the functionalization densities using electrochemical methods, samples with low grafting densities were characterized by low-temperature scanning tunneling microscopy (LT-STM). We show that the use of buffer-layer free graphene substrates is required for clear observation of the nitrophenyl modifications. Furthermore, atomically-resolved STM images of single site modifications were obtained, showing no preferential grafting at defect sites or SiC step edges as supposed previously in the literature. Most of the grafts exhibit threefold symmetry, but occasional extended modifications (larger than 4 nm) were observed as well.« less

  19. Atom-scale covalent electrochemical modification of single-layer graphene on SiC substrates by diaryliodonium salts

    SciTech Connect

    Gearba, Raluca I.; Mueller, Kory M.; Veneman, Peter A.; Holliday, Bradley J.; Chan, Calvin K.; Stevenson, Keith J.

    2015-05-09

    Owing to its high conductivity, graphene holds promise as an electrode for energy devices such as batteries and photovoltaics. However, to this end, the work function and doping levels in graphene need to be precisely tuned. One promising route for modifying graphene’s electronic properties is via controlled covalent electrochemical grafting of molecules. We show that by employing diaryliodonium salts instead of the commonly used diazonium salts, spontaneous functionalization is avoided. This then allows for precise tuning of the grafting density. Moreover, by employing bis(4-nitrophenyl)iodonium(III) tetrafluoroborate (DNP) salt calibration curves, the surface functionalization density (coverage) of glassy carbon was controlled using cyclic voltammetry in varying salt concentrations. These electro-grafting conditions and calibration curves translated directly over to modifying single layer epitaxial graphene substrates (grown on insulating 6H-SiC (0 0 0 1)). In addition to quantifying the functionalization densities using electrochemical methods, samples with low grafting densities were characterized by low-temperature scanning tunneling microscopy (LT-STM). We show that the use of buffer-layer free graphene substrates is required for clear observation of the nitrophenyl modifications. Furthermore, atomically-resolved STM images of single site modifications were obtained, showing no preferential grafting at defect sites or SiC step edges as supposed previously in the literature. Most of the grafts exhibit threefold symmetry, but occasional extended modifications (larger than 4 nm) were observed as well.

  20. Modification of Ti6Al4V Substrates with Well-defined Zwitterionic Polysulfobetaine Brushes for Improved Surface Mineralization

    PubMed Central

    2015-01-01

    Osteoconductive mineral coatings are beneficial for improving the osteointegration of metallic orthopedic/dental implants, but achieving adequate structural integration between the surface minerals and underlying metallic substrates has been a significant challenge. Here, we report covalent grafting of zwitterionic poly(sulfobetaine methacrylate) (pSBMA) brushes on the Ti6Al4V substrates to promote the surface-mineralization of hydroxyapatite with enhanced surface mineral coverage and mineral-substrate interfacial adhesion. We first optimized the atom transfer radical polymerization (ATRP) conditions for synthesizing pSBMA polymers in solution. Well-controlled pSBMA polymers (relative molecular weight up to 26kD, PDI = 1.17) with high conversions were obtained when the ATRP was carried out in trifluoroethanol/ionic liquid system at 60 °C. Applying identical polymerization conditions, surface-initiated atom transfer radical polymerization (SI-ATRP) was carried out to graft zwitterionic pSBMA brushes (PDI < 1.20) from the Ti6Al4V substrates, generating a stable superhydrophilic and low-fouling surface coating without compromising the bulk mechanic property of the Ti6Al4V substrates. The zwitterionic pSBMA surface brushes, capable of attracting both cationic and anionic precursor ions during calcium phosphate apatite mineralization, increased the surface mineral coverage from 32% to 71%, and significantly reinforced the attachment of the apatite crystals on the Ti6Al4V substrate. This facile approach to surface modification of metallic substrates can be exploited to generate multifunctional polymer coatings and improve the performance of metallic implants in skeletal tissue engineering and orthopedic and dental care. PMID:24828749

  1. ITOS meteorological satellite system: TIROS M spacecraft (ITOS 1), volume 1

    NASA Technical Reports Server (NTRS)

    1970-01-01

    The ITOS system and mission are described along with the design of the TIROS M spacecraft, and the ITOS ground complex. The command subsystems, and the primary environmental sensor subsystem are discussed.

  2. Supersymmetric Ito equation: Bosonization and exact solutions

    SciTech Connect

    Ren Bo; Yu Jun; Lin Ji

    2013-04-15

    Based on the bosonization approach, the N=1 supersymmetric Ito (sIto) system is changed to a system of coupled bosonic equations. The approach can effectively avoid difficulties caused by intractable fermionic fields which are anticommuting. By solving the coupled bosonic equations, the traveling wave solutions of the sIto system are obtained with the mapping and deformation method. Some novel types of exact solutions for the supersymmetric system are constructed with the solutions and symmetries of the usual Ito equation. In the meanwhile, the similarity reduction solutions of the model are also studied with the Lie point symmetry theory.

  3. Agarose-Based Substrate Modification Technique for Chemical and Physical Guiding of Neurons In Vitro.

    PubMed

    Krumpholz, Katharina; Rogal, Julia; El Hasni, Akram; Schnakenberg, Uwe; Bräunig, Peter; Bui-Göbbels, Katrin

    2015-08-26

    A new low cost and highly reproducible technique is presented that provides patterned cell culture substrates. These allow for selective positioning of cells and a chemically and mechanically directed guiding of their extensions. The patterned substrates consist of structured agarose hydrogels molded from reusable silicon micro templates. These templates consist of pins arranged equidistantly in squares, connected by bars, which mold corresponding wells and channels in the nonadhesive agarose hydrogel. Subsequent slice production with a standard vibratome, comprising the described template pattern, completes substrate production. Invertebrate neurons of locusts and pond snails are used for this application as they offer the advantage over vertebrate cells as being very large and suitable for cultivation in low cell density. Their neurons adhere to and grow only on the adhesive areas not covered by the agarose. Agarose slices of 50 μm thickness placed on glass, polystyrene, or MEA surfaces position and immobilize the neurons in the wells, and the channels guide their neurite outgrowth toward neighboring wells. In addition to the application with invertebrate neurons, the technique may also provide the potential for the application of a wide range of cell types. Long-term objective is the achievement of isolated low-density neuronal networks on MEAs or different culture substrates for various network analysis applications.

  4. Highly Stretchable and Flexible Graphene/ITO Hybrid Transparent Electrode

    NASA Astrophysics Data System (ADS)

    Liu, Juhua; Yi, Yaohua; Zhou, Yihua; Cai, Huafei

    2016-02-01

    The flexible hybrid transparent electrode was prepared by a two-step process: graphene film was firstly grown on Cu foil by modified thermal chemical vapor deposition (CVD) and then transferred onto indium tin oxide (ITO) electrode on the polyethylene terephthalate (PET) substrate. The quality of the graphene is characterized by various analytic techniques, including the AFM, SEM, TEM, and Raman spectroscopy. The gradient flux was found to be beneficial to decrease defect. The thickness, morphology, light transmittance, and electromechanical properties of three conductive electrodes were investigated and compared. The outcomes show that the hybrid electrode could resist mechanical force and the results are better than original ITO electrode. It may be a potential trend to apply the graphene to other conducts in the flexible transparent conductive field.

  5. Catalyst-free growth of ZnO nanowires on ITO seed/glass by thermal evaporation method: Effects of ITO seed layer thickness

    NASA Astrophysics Data System (ADS)

    Alsultany, Forat H.; Hassan, Z.; Ahmed, Naser M.

    2016-07-01

    A seed/catalyst-free growth of ZnO nanowires (ZnO-NWs) on a glass substrate were successfully fabricated using thermal evaporation technique. These nanowires were grown on ITO seed layers of different thicknesses of 25 and 75 nm, which were deposited on glass substrates by radio frequency (RF) magnetron sputtering. Prior to synthesized ITO nanowires, the sputtered ITO seeds were annealed using the continuous wave (CW) CO2 laser at 450 °C in air for 15 min. The effect of seed layer thickness on the morphological, structural, and optical properties of ZnO-NWs were systematically investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and UV-Vis spectrophotometer.

  6. Chemical mechanical polishing characteristics of ITO thin film prepared by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Lee, Kang-Yeon; Choi, Gwon-Woo; Kim, Yong-Jae; Choi, Youn-Ok; Kim, Nam-Oh

    2012-02-01

    Indium-tin-oxide (ITO) thin films have attracted intensive interest because of their unique properties of good conductivity, high optical transmittance over the visible region and easy patterning ability. ITO thin films have found many applications in anti-static coatings, thermal heaters, solar cells, flat panel displays (FPDs), liquid crystal displays (LCDs), electroluminescent devices, sensors and organic light-emitting diodes (OLEDs). ITO thin films are generally fabricated by using various methods, such as spraying, chemical vapor deposition (CVD), evaporation, electron gun deposition, direct current electroplating, high frequency sputtering, and reactive sputtering. In this research, ITO films were grown on glass substrates by using a radio-frequency (RF) magnetron sputtering method. In order to achieve a high transmittance and a low resistivity, we examined the various film deposition conditions, such as substrate temperature, working pressure, annealing temperature, and deposition time. Next, in order to improve the surface quality of the ITO thin films, we performed a chemical mechanical polishing (CMP) with different process parameters and compared the electrical and the optical properties of the polished ITO thin films. The best CMP conditions with a high removal rate, low nonuniformity, low resistivity and high transmittance were as follows: platen speed, head speed, polishing time, and slurry flow rate of 30 rpm, 30 rpm, 60 sec, and 60 ml/min, respectively.

  7. Interfacial modification of amorphous substrates for microcrystalline silicon growth with in situ hydrogen plasma pretreatment

    NASA Astrophysics Data System (ADS)

    Park, Young-Bae; Rhee, Shi-Woo; Li, Xiaodong

    2005-10-01

    Microcrystalline silicon (μc-Si:H) films have been deposited onto hydrogenated and amorphous Si-rich silicon nitride and thermal oxide substrates with silane (SiH4)-hydrogen (H2) in remote plasma-enhanced chemical vapor deposition (RPECVD) at 250 °C, and these films have been investigated. It is found that in situ hydrogen plasma pretreatment of the amorphous substrates prior to μc-Si:H deposition is effective in reducing the interfacial amorphous transition region. It is believed that this hydrogen plasma pretreatment gives adsorption and nucleation sites by breaking weak Si-N and Si-Si bonds and also removes native Si-O x and hydrocarbon impurities. In the case of SiNx:H surface, surface roughening from atomic hydrogen etching and surface cleaning effects are greater than those for stable thermal oxide. Surface crystallization at the initial stage of the growth can be obtained on amorphous substrate at low temperature without an a-Si transition layer.

  8. Fabrication of Bi-doped In2O3-ITO nanocomposites and their photoluminescence properties

    NASA Astrophysics Data System (ADS)

    Gil Na, Han; Jung, Taek-Kyun; Lee, Ji-Woon; Hyun, Soong-Keun; Kwon, Yong Jung; Mirzaei, Ali; Kim, Tae-Bum; Shin, Young-Chul; Choi, Ho-Joon; Kim, Hyoun Woo; Jin, Changhyun

    2016-09-01

    For the first time, Bi-doped In2O3-indium tin oxide (ITO) nanocomposites were prepared on Si substrates with the assistance of a Au catalyst through the simple gas-phase transport of a mixture of Bi, In, and Sn powders. The square-shaped Bi-doped In2O3-ITO nanostructures were straight, a few hundreds of nanometres in width, and below a few tens of micrometres in length. Electron microscopy, x-ray diffraction, and energy-dispersive x-ray spectroscopy analyses indicated that the Bi-doped In2O3-ITO nanorods were single crystals with a basis of cubic In2O3 structures. The photoluminescence spectra revealed that the Bi-doped In2O3-ITO nanorods had a strong orange emission band centred at approximately 626 nm without any shoulder bands. The enhancement of orange emission might be due to the oxygen deficiencies of structural defects in the nanorods.

  9. Fast anodization fabrication of AAO and barrier perforation process on ITO glass.

    PubMed

    Liu, Sida; Xiong, Zuzhou; Zhu, Changqing; Li, Ma; Zheng, Maojun; Shen, Wenzhong

    2014-01-01

    Thin films of porous anodic aluminum oxide (AAO) on tin-doped indium oxide (ITO) substrates were fabricated through evaporation of a 1,000- to 2,000-nm-thick Al, followed by anodization with different durations, electrolytes, and pore widening. A faster method to obtain AAO on ITO substrates has been developed, which with 2.5 vol.% phosphoric acid at a voltage of 195 V at 269 K. It was found that the height of AAO films increased initially and then decreased with the increase of the anodizing time. Especially, the barrier layers can be removed by extending the anodizing duration, which is very useful for obtaining perforation AAO and will broaden the application of AAO on ITO substrates.

  10. Fast anodization fabrication of AAO and barrier perforation process on ITO glass

    PubMed Central

    2014-01-01

    Thin films of porous anodic aluminum oxide (AAO) on tin-doped indium oxide (ITO) substrates were fabricated through evaporation of a 1,000- to 2,000-nm-thick Al, followed by anodization with different durations, electrolytes, and pore widening. A faster method to obtain AAO on ITO substrates has been developed, which with 2.5 vol.% phosphoric acid at a voltage of 195 V at 269 K. It was found that the height of AAO films increased initially and then decreased with the increase of the anodizing time. Especially, the barrier layers can be removed by extending the anodizing duration, which is very useful for obtaining perforation AAO and will broaden the application of AAO on ITO substrates. PMID:24708829

  11. Transparent ITO/Ag-Pd-Cu/ITO multilayer cathode use in inverted organic solar cells

    SciTech Connect

    Kim, Hyo-Joong; Kim, Han-Ki; Lee, Hyun Hwi; Kal, Jinha; Hahn, Jungseok

    2015-10-15

    The characteristics of transparent ITO/Ag-Pd-Cu (APC)/ITO multilayer cathodes were investigated for use in inverted organic solar cells (IOSCs). The insertion of an APC interlayer into the ITO film effectively led to crystallization of the top ITO layer, unlike that in the Ag interlayer, and resulted in a low sheet resistance of 6.55 Ohm/square and a high optical transmittance of 84.14% without post annealing. In addition, the alloying of the Pd and Cu elements into Ag prevented agglomeration and oxidization of the metal interlayer and led to more stable ITO/APC/ITO films under ambient conditions. The microstructure and interfacial structure of the transparent ITO/APC/ITO cathode in the IOSCs were examined in detail by synchrotron X-ray scattering and high resolution transmission electron microscopy. Furthermore, we suggested a possible mechanism to explain the lower PCE of the IOSCs with an ITO/APC/ITO cathode than that of a reference IOSC with a crystalline ITO cathode using the external quantum efficiency of the IOSCs.

  12. Hierarchical zwitterionic modification of a SERS substrate enables real-time drug monitoring in blood plasma

    PubMed Central

    Sun, Fang; Hung, Hsiang-Chieh; Sinclair, Andrew; Zhang, Peng; Bai, Tao; Galvan, Daniel David; Jain, Priyesh; Li, Bowen; Jiang, Shaoyi; Yu, Qiuming

    2016-01-01

    Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive analytical technique with molecular specificity, making it an ideal candidate for therapeutic drug monitoring (TDM). However, in critical diagnostic media including blood, nonspecific protein adsorption coupled with weak surface affinities and small Raman activities of many analytes hinder the TDM application of SERS. Here we report a hierarchical surface modification strategy, first by coating a gold surface with a self-assembled monolayer (SAM) designed to attract or probe for analytes and then by grafting a non-fouling zwitterionic polymer brush layer to effectively repel protein fouling. We demonstrate how this modification can enable TDM applications by quantitatively and dynamically measuring the concentrations of several analytes—including an anticancer drug (doxorubicin), several TDM-requiring antidepressant and anti-seizure drugs, fructose and blood pH—in undiluted plasma. This hierarchical surface chemistry is widely applicable to many analytes and provides a generalized platform for SERS-based biosensing in complex real-world media. PMID:27834380

  13. Hierarchical zwitterionic modification of a SERS substrate enables real-time drug monitoring in blood plasma

    NASA Astrophysics Data System (ADS)

    Sun, Fang; Hung, Hsiang-Chieh; Sinclair, Andrew; Zhang, Peng; Bai, Tao; Galvan, Daniel David; Jain, Priyesh; Li, Bowen; Jiang, Shaoyi; Yu, Qiuming

    2016-11-01

    Surface-enhanced Raman spectroscopy (SERS) is an ultrasensitive analytical technique with molecular specificity, making it an ideal candidate for therapeutic drug monitoring (TDM). However, in critical diagnostic media including blood, nonspecific protein adsorption coupled with weak surface affinities and small Raman activities of many analytes hinder the TDM application of SERS. Here we report a hierarchical surface modification strategy, first by coating a gold surface with a self-assembled monolayer (SAM) designed to attract or probe for analytes and then by grafting a non-fouling zwitterionic polymer brush layer to effectively repel protein fouling. We demonstrate how this modification can enable TDM applications by quantitatively and dynamically measuring the concentrations of several analytes--including an anticancer drug (doxorubicin), several TDM-requiring antidepressant and anti-seizure drugs, fructose and blood pH--in undiluted plasma. This hierarchical surface chemistry is widely applicable to many analytes and provides a generalized platform for SERS-based biosensing in complex real-world media.

  14. Insights into Phosphate Cooperativity and Influence of Substrate Modifications on Binding and Catalysis of Hexameric Purine Nucleoside Phosphorylases

    PubMed Central

    de Giuseppe, Priscila O.; Martins, Nadia H.; Meza, Andreia N.; dos Santos, Camila R.; Pereira, Humberto D’Muniz; Murakami, Mario T.

    2012-01-01

    The hexameric purine nucleoside phosphorylase from Bacillus subtilis (BsPNP233) displays great potential to produce nucleoside analogues in industry and can be exploited in the development of new anti-tumor gene therapies. In order to provide structural basis for enzyme and substrates rational optimization, aiming at those applications, the present work shows a thorough and detailed structural description of the binding mode of substrates and nucleoside analogues to the active site of the hexameric BsPNP233. Here we report the crystal structure of BsPNP233 in the apo form and in complex with 11 ligands, including clinically relevant compounds. The crystal structure of six ligands (adenine, 2′deoxyguanosine, aciclovir, ganciclovir, 8-bromoguanosine, 6-chloroguanosine) in complex with a hexameric PNP are presented for the first time. Our data showed that free bases adopt alternative conformations in the BsPNP233 active site and indicated that binding of the co-substrate (2′deoxy)ribose 1-phosphate might contribute for stabilizing the bases in a favorable orientation for catalysis. The BsPNP233-adenosine complex revealed that a hydrogen bond between the 5′ hydroxyl group of adenosine and Arg43* side chain contributes for the ribosyl radical to adopt an unusual C3’-endo conformation. The structures with 6-chloroguanosine and 8-bromoguanosine pointed out that the Cl6 and Br8 substrate modifications seem to be detrimental for catalysis and can be explored in the design of inhibitors for hexameric PNPs from pathogens. Our data also corroborated the competitive inhibition mechanism of hexameric PNPs by tubercidin and suggested that the acyclic nucleoside ganciclovir is a better inhibitor for hexameric PNPs than aciclovir. Furthermore, comparative structural analyses indicated that the replacement of Ser90 by a threonine in the B. cereus hexameric adenosine phosphorylase (Thr91) is responsible for the lack of negative cooperativity of phosphate binding in this

  15. Modification of the substrate specificity of porcine pepsin for the enzymatic production of bovine hide gelatin.

    PubMed Central

    Galea, C. A.; Dalrymple, B. P.; Kuypers, R.; Blakeley, R.

    2000-01-01

    The substrate specificity of porcine pepsin has been altered by site-directed mutagenesis in an attempt to selectively cleave bovine hide collagen at only a few sites, similar to cathepsin D, for the production of high quality gelatin. Kinetic parameters were determined using chromogenic peptide substrates based on the sequence Lys-Pro-Xaa-Yaa-Phe*Nph-Arg-Leu (where Xaa is Ile or Pro, Yaa is Glu. Leu, Gln or Lys, Nph is p-nitrophenylalanine, and * is the site of cleavage). Substitution of Thr222 and Glu287 within the S2 subsite of pepsin by Val and Met, respectively, produced a double mutant with a two- to fourfold higher kcat/Km, compared with wild-type pepsin, for the chromogenic peptides with residues Leu, Gln, and Glu at position P2 (Yaa). The results suggest that the functional group of the P2 side chain may be exposed to solvent, while the aliphatic portion interacts with hydrophobic residues comprising S2. Wild-type pepsin cleaved a peptide corresponding to the carboxy-terminal telopeptide region of bovine type I collagen alpha1 chain, SGGYDLSFLPQPPQE, predominantly at three sites (Asp-Leu, Leu-Ser, and Phe-Leu) and at a significantly lower rate at Ser-Phe. However, Thr222Val/Glu287Met cleaved site Ser-Phe at a rate 20-fold higher than the wild-type. Significantly, enzymes containing the double substitution Phe111Thr/Leu112Phe cleaved this peptide predominantly at one site Leu-Ser (similar to cathepsin D) and at a rate 23-fold higher than the wild-type. These mutants can potentially enhance the rate of solubilization of bovine hide collagen under conditions mild enough to maintain the triple helix structure and hence minimize the rate of subsequent denaturation and proteolytic cleavage. PMID:11106168

  16. The influence of surface modification on bacterial adhesion to titanium-based substrates.

    PubMed

    Lorenzetti, Martina; Dogša, Iztok; Stošicki, Tjaša; Stopar, David; Kalin, Mitjan; Kobe, Spomenka; Novak, Saša

    2015-01-28

    This study examines bacterial adhesion on titanium-substrates used for bone implants. Adhesion is the most critical phase of bacterial colonization on medical devices. The surface of titanium was modified by hydrothermal treatment (HT) to synthesize nanostructured TiO2-anatase coatings, which were previously proven to improve corrosion resistance, affect the plasma protein adsorption, and enhance osteogenesis. The affinity of the anatase coatings toward bacterial attachment was studied by using a green fluorescent protein-expressing Escherichia coli (gfp-E. coli) strain in connection with surface photoactivation by UV irradiation. We also analyzed the effects of surface topography, roughness, charge, and wettability. The results suggested the dominant effects of the macroscopic surface topography, as well as microasperity at the surface roughness scale, which were produced during titanium machining, HT treatment, or both. Macroscopic grooves provided a preferential site for bacteria deposit within the valleys, while the microscopic roughness of the valleys determined the actual interaction surface between bacterium and substrate, resulting in an "interlocking" effect and undesired high bacterial adhesion on nontreated titanium. In the case of TiO2-coated samples, the nanocrystals reduced the width between the microasperities and thus added nanoroughness features. These factors decreased the contact area between the bacterium and the coating, with consequent lower bacterial adhesion (up to 50% less) in comparison to the nontreated titanium. On the other hand, the pronounced hydrophilicity of one of the HT-coated discs after pre-irradiation seemed to enhance the attachment of bacteria, although the increase was not statistically significant (p > 0.05). This observation may be explained by the acquired similar degree of wetting between gfp-E. coli and the coating. No correlation was found between the bacterial adhesion and the ζ-values of the samples in PBS, so the

  17. ZnS nanoparticles electrodeposited onto ITO electrode as a platform for fabrication of enzyme-based biosensors of glucose.

    PubMed

    Du, Jian; Yu, Xiuping; Wu, Ying; Di, Junwei

    2013-05-01

    The electrochemical and photoelectrochemical biosensors based on glucose oxidase (GOD) and ZnS nanoparticles modified indium tin oxide (ITO) electrode were investigated. The ZnS nanoparticles were electrodeposited directly on the surface of ITO electrode. The enzyme was immobilized on ZnS/ITO electrode surface by sol-gel method to fabricate glucose biosensor. GOD could electrocatalyze the reduction of dissolved oxygen, which resulted in a great increase of the reduction peak current. The reduction peak current decreased linearly with the addition of glucose, which could be used for glucose detection. Moreover, ZnS nanoparticles deposited on ITO electrode surface showed good photocurrent response under illumination. A photoelectrochemical biosensor for the detection of glucose was also developed by monitoring the decreases in the cathodic peak photocurrent. The results indicated that ZnS nanoparticles deposited on ITO substrate were a good candidate material for the immobilization of enzyme in glucose biosensor construction.

  18. A simple two-step method to fabricate highly transparent ITO/polymer nanocomposite films

    NASA Astrophysics Data System (ADS)

    Liu, Haitao; Zeng, Xiaofei; Kong, Xiangrong; Bian, Shuguang; Chen, Jianfeng

    2012-09-01

    Transparent functional indium tin oxide (ITO)/polymer nanocomposite films were fabricated via a simple approach with two steps. Firstly, the functional monodisperse ITO nanoparticles were synthesized via a facile nonaqueous solvothermal method using bifunctional chemical agent (N-methyl-pyrrolidone, NMP) as the reaction solvent and surface modifier. Secondly, the ITO/acrylics polyurethane (PUA) nanocomposite films were fabricated by a simple sol-solution mixing method without any further surface modification step as often employed traditionally. Flower-like ITO nanoclusters with about 45 nm in diameter were mono-dispersed in ethyl acetate and each nanocluster was assembled by nearly spherical nanoparticles with primary size of 7-9 nm in diameter. The ITO nanoclusters exhibited an excellent dispersibility in polymer matrix of PUA, remaining their original size without any further agglomeration. When the loading content of ITO nanoclusters reached to 5 wt%, the transparent functional nanocomposite film featured a high transparency more than 85% in the visible light region (at 550 nm), meanwhile cutting off near-infrared radiation about 50% at 1500 nm and blocking UV ray about 45% at 350 nm. It could be potential for transparent functional coating materials applications.

  19. Catalytic wateroxidation on derivatized nanoITO

    SciTech Connect

    Chen, Zuofeng; Concepcion, Javier J; Hull, Jonathan F; Hoertz, Paul G.; Meyer, Thomas J.

    2010-06-22

    Electrocatalytic water oxidation occurs on high surface area, nanocrystalline ITO (nanoITO) surface-derivatized by phosphonate-binding of the catalyst [Ru(Mebimpy)(4,4'-((HO)2OPCH2)2bpy)(OH2)]2+ (Mebimpy is 2,6-bis(1-methylbenzimidazol-2-yl)pyridine; bpy is 2,2'-bipyridine). With nanoITO, spectral data can be acquired on electrochemically generated intermediates and voltammograms monitored spectrophotometrically.

  20. Pulsed modification of germanium films on silicon, sapphire, and quartz substrates: Structure and optical properties

    SciTech Connect

    Novikov, H. A.; Batalov, R. I. Bayazitov, R. M.; Faizrakhmanov, I. A.; Lyadov, N. M.; Shustov, V. A.; Galkin, K. N.; Galkin, N. G.; Chernev, I. M.; Ivlev, G. D.; Prokop’ev, S. L.; Gaiduk, P. I.

    2015-06-15

    The structural and optical properties of thin Ge films deposited onto semiconducting and insulating substrates and modified by pulsed laser radiation are studied. The films are deposited by the sputtering of a Ge target with a low-energy Xe{sup +} ion beam. Crystallization of the films is conducted by their exposure to nanosecond ruby laser radiation pulses (λ = 0.694 μm) with the energy density W = 0.2−1.4 J cm{sup −2}. During pulsed laser treatment, the irradiated area is probed with quasi-cw (quasi-continuous-wave) laser radiation (λ = 0.532 and 1.064 μm), with the reflectance recorded R(t). Experimental data on the lifetime of the Ge melt are compared with the results of calculation, and good agreement between them is demonstrated. Through the use of a number of techniques, the dependences of the composition of the films, their crystal structure, the level of strains, and the reflectance and transmittance on the conditions of deposition and annealing are established.

  1. Effective surface modification by chemical solution deposition for flexible metal substrates

    NASA Astrophysics Data System (ADS)

    Du, Wei; Bai, Yue-Ling; Wang, Jing; Fang, Jianhui; Fan, Feng; Liu, Zhiyong; Guo, Yanqun; Bai, Chuanyi; Cai, Chuanbing

    2017-03-01

    Solution deposition planarization (SDP) was used to modify the flexible metal substrates for high temperature superconductor (HTS) tapes to ensure an available and effective surface for subsequent growth of buffer films. The surface morphologies with different tape speeds and coating layers were systematically investigated. 16 layers SDP-films decreased the surface roughness (RMS) from 11.74 to 0.788 nm for Hastelloy C-276 and 12 layers SDP-films decreased the RMS from 20.93 to 0.903 nm for SUS 304. Follow-up study confirmed that the low value of RMS (<1 nm) and high reflectivity of SDP-films exhibit superior characteristics for ion beam-assisted deposited (IBAD)-MgO, sputtered LaMnO3 films and YBCO films. A 10 m sample verified the stability of SDP-films on Hastelloy. The similar result for achieved SDP-films on SUS 304 (I cAVG  =  110.1 A) and Hastelloy (I cAVG  =  124.5 A) revealed the stainless steel has potential application value for coated conductor, which further reduced the cost of raw materials.

  2. Controllably annealed CuO-nanoparticle modified ITO electrodes: Characterisation and electrochemical studies

    NASA Astrophysics Data System (ADS)

    Wang, Tong; Su, Wen; Fu, Yingyi; Hu, Jingbo

    2016-12-01

    In this paper, we report a facile and controllable two-step approach to produce indium tin oxide electrodes modified by copper(II) oxide nanoparticles (CuO/ITO) through ion implantation and annealing methods. After annealing treatment, the surface morphology of the CuO/ITO substrate changed remarkably and exhibited highly electroactive sites and a high specific surface area. The effects of annealing treatment on the synthesis of CuO/ITO were discussed based on various instruments' characterisations, and the possible mechanism by which CuO nanoparticles were generated was also proposed in this work. Cyclic voltammetric results indicated that CuO/ITO electrodes exhibited effective catalytic responses toward glucose in alkaline solution. Under optimal experimental conditions, the proposed CuO/ITO electrode showed sensitivity of 450.2 μA cm-2 mM-1 with a linear range of up to ∼4.4 mM and a detection limit of 0.7 μM (S/N = 3). Moreover, CuO/ITO exhibited good poison resistance, reproducibility, and stability properties.

  3. Modification of the substrate specificity of an acyl-acyl carrier protein thioesterase by protein engineering.

    PubMed

    Yuan, L; Voelker, T A; Hawkins, D J

    1995-11-07

    The plant acyl-acyl carrier protein (ACP) thioesterases (TEs) are of biochemical interest because of their roles in fatty acid synthesis and their utilities in the bioengineering of plant seed oils. When the FatB1 cDNA encoding a 12:0-ACP TE (Uc FatB1) from California bay, Umbellularia californica (Uc) was expressed in Escherichia coli and in developing oilseeds of the plants Arabidopsis thaliana and Brassica napus, large amounts of laurate (12:0) and small amounts of myristate (14:0) were accumulated. We have isolated a TE cDNA from camphor (Cinnamomum camphorum) (Cc) seeds that shares 92% amino acid identity with Uc FatB1. This TE, Cc FatB1, mainly hydrolyzes 14:0-ACP as shown by E. coli expression. We have investigated the roles of the N- and C-terminal regions in determining substrate specificity by constructing two chimeric enzymes, in which the N-terminal portion of one protein is fused to the C-terminal portion of the other. Our results show that the C-terminal two-thirds of the protein is critical for the specificity. By site-directed mutagenesis, we have replaced several amino acids in Uc FatB1 by using the Cc FatB1 sequence as a guide. A double mutant, which changes Met-197 to an Arg and Arg-199 to a His (M197R/R199H), turns Uc FatB1 into a 12:0/14:0 TE with equal preference for both substrates. Another mutation, T231K, by itself does not effect the specificity. However, when it is combined with the double mutant to generate a triple mutant (M197R/R199H/T231K), Uc FatB1 is converted to a 14:0-ACP TE. Expression of the double-mutant cDNA in E. coli K27, a strain deficient in fatty acid degradation, results in accumulation of similar amounts of 12:0 and 14:0. Meanwhile the E. coli expressing the triple-mutant cDNA produces predominantly 14:0 with very small amounts of 12:0. Kinetic studies indicate that both wild-type Uc FatB1 and the triple mutant have similar values of Km,app with respect to 14:0-ACP. Inhibitory studies also show that 12:0-ACP is a good

  4. Hypomelanosis of Ito associated with precocious puberty.

    PubMed

    Rutland, Beth M; Edgar, Mark A; Horenstein, Marcelo G

    2006-01-01

    Hypomelanosis of Ito has been associated with precocious puberty in two cases. This study reports a third case involving a female with hypomelanosis of Ito including severe mental retardation and seizure disorder with autonomic symptoms (gastroesophageal reflux and asthma). At age 5 she developed vaginal discharge, thelarche, and adrenarche. Soon after, she died of pneumonia stemming from her neurologic deficits. A postmortem examination revealed normal gonads and endocrine organs. The breasts and vulva were prematurely developed. Central nervous system findings included megalencephaly, neuronal eosinophilic inclusions, leptomeningeal neuroglial heterotopias, and cortical dysplasia. Both previously reported cases of hypomelanosis of Ito associated with precocious puberty had abnormal gonads and responded to cyproterone acetate therapy, indicating a peripheral mechanism of precocious puberty (gonadotrophin-independent). The current case, which was autopsied, lacks significant gonadal pathology, and has extensive neurologic involvement that suggests that a central mechanism of precocious puberty (gonadotrophin-dependent) can also be associated with hypomelanosis of Ito.

  5. Roll-to-roll cohesive, coated, flexible, high-efficiency polymer light-emitting diodes utilizing ITO-free polymer anodes.

    PubMed

    Shin, Seongbeom; Yang, Minyang; Guo, L Jay; Youn, Hongseok

    2013-12-09

    This paper reports solution-processed, high-efficiency polymer light-emitting diodes fabricated by a new type of roll-to-roll coating method under ambient air conditions. A noble roll-to-roll cohesive coating system utilizes only natural gravity and the surface tension of the solution to flow out from the capillary to the surface of the substrate. Because this mechanism uses a minimally cohesive solution, the roll-to-roll cohesive coating can effectively realize an ultra-thin film thickness for the electron injection layer. In addition, the roll-to-roll cohesive coating enables the fabrication of a thicker polymer anode film more than 250 nm at one time by modification of the surface energy and without wasting the solution. It is observed that the standard sheet resistance deviation of the polymer anode is only 2.32 Ω/□ over 50 000 bending cycles. The standard sheet resistance deviation of the polymer anode in the different bending angles (0 to 180°) is 0.313 Ω/□, but the case of the ITO-PET is 104.93 Ω/□. The average surface roughness of the polymer anode measured by atomic force microscopy is only 1.06 nm. Because the surface of the polymer anode has a better quality, the leakage current of the polymer light-emitting diodes (PLEDs) using the polymer anode is much lower than that using the ITO-PET substrate. The luminous power efficiency of the two devices is 4.13 lm/W for the polymer anode and 3.21 lm/W for the ITO-PET. Consequently, the PLEDs made by using the polymer anode exhibited 28% enhanced performance because the polymer anode represents not only a higher transparency than the ITO-PET in the wavelength of 560 nm but also greatly reduced roughness. The optimized the maximum current efficiency and power efficiency of the device show around 6.1 cd/A and 5.1 lm/W, respectively, which is comparable to the case of using the ITO-glass.

  6. Effects of electron irradiation during the growth of ITO films by an using RF sputtering system

    NASA Astrophysics Data System (ADS)

    Yoon, Young Joon; Cho, Sung Hwan; Kim, Bongho

    2016-10-01

    We perform electron irradiation during the radio-frequency (RF) sputtering process to realize the growth of a transparent oxide thin film, indium tin oxide (ITO), to achieve a high transparency and a low resistivity. Using an electron gun attached to the sputtering system, we simultaneously accelerate a large number of electrons onto the substrate along with the sputtered ITO atoms by using a negative bias of up to 1.5 kV. As the electron-beam voltage increased, the preferred orientation of the ITO film changed from the (222) plane to the (400) plane, and the film showed a flake-type surface morphology. Sputtered ITO atoms in the electron-assisted sputtering (EAS) process showed sufficient mobility because of the kinetic effect of continuous electron irradiation without the need for an additional substrate heating process. The ITO films grown using the EAS process had a minimum resistivity value of 1.46×10-4 Ωcm under an electron irradiation condition of 1.5 kV and showed a transmittance of 95% at 550 nm.

  7. Increased efficiency with surface texturing in ITO/InP solar cells

    NASA Technical Reports Server (NTRS)

    Jenkins, Phillip; Landis, Geoffrey A.; Fatemi, Navid; Li, Xiaonan; Scheiman, David; Bailey, Sheila

    1992-01-01

    Optimization of an InP solar cell with a V-grooved surface is discussed. Total internal reflection in the coverglass reduces surface reflection and can recover light reflected from the front metallization. Results from the first ITO/InP solar cells on low-angle V-grooved substrates are presented, showing a 5.8 percent increase in current.

  8. Preparation and modification of VO2 thin film on R-sapphire substrate by rapid thermal process

    NASA Astrophysics Data System (ADS)

    Zhu, Nai-Wei; Hu, Ming; Xia, Xiao-Xu; Wei, Xiao-Ying; Liang, Ji-Ran

    2014-04-01

    The VO2 thin film with high performance of metal-insulator transition (MIT) is prepared on R-sapphire substrate for the first time by magnetron sputtering with rapid thermal process (RTP). The electrical characteristic and THz transmittance of MIT in VO2 film are studied by four-point probe method and THz time domain spectrum (THz-TDS). X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and search engine marketing (SEM) are employed to analyze the crystalline structure, valence state, surface morphology of the film. Results indicate that the properties of VO2 film which is oxidized from the metal vanadium film in oxygen atmosphere are improved with a follow-up RTP modification in nitrogen atmosphere. The crystallization and components of VO2 film are improved and the film becomes compact and uniform. A better phase transition performance is shown that the resistance changes nearly 3 orders of magnitude with a 2-°C hysteresis width and the THz transmittances are reduced by 64% and 60% in thermal and optical excitation respectively.

  9. Atrial Substrate Modification in Atrial Fibrillation: Targeting GP or CFAE? Evidence from Meta-Analysis of Clinical Trials

    PubMed Central

    Qin, Mu; Liu, Xu; Wu, Shao-Hui; Zhang, Xiao-Dong

    2016-01-01

    Several clinically relevant outcomes post atrial substrate modification in patients with atrial fibrillation (AF) have not been systematically analyzed among published studies on adjunctive cardiac ganglionated plexi (GP) or complex fractionated atrial electograms (CFAE) ablation vs. pulmonary vein isolation (PVI) alone. Out of 176 reports identified, the present meta-analysis included 14 randomized and non-randomized controlled trials (1613 patients) meeting inclusion criteria. Addition of GP ablation to PVI significantly increased freedom from atrial tachyarrhythmia in short- (OR: 1.72; P = 0.003) and long-term (OR: 2.0, P = 0.0006) follow-up, while adjunctive CFAE ablation did not after one or repeat procedure (P<0.05). The percentage of atrial tachycardia or atrial flutter (AT/AFL) after one procedure was higher for CFAE than GP ablation. In sub-analysis of non-paroxysmal AF, relative to PVI alone, adjunctive GP but not CFAE ablation significantly increased sinus rhythm maintenance (OR: 1.88, P = 0.01; and OR:1.24, P = 0.18, respectively). Meta regression analysis of the 14 studies indicated that sample size was significant source of heterogeneity either in outcomes after one or repeat procedure. In conclusion, in patients with AF, adjunctive GP but not CFAE ablation appeared to significantly add to the beneficial effects on sinus rhythm maintenance of PVI ablation alone; and CFAE ablation was associated with higher incidence of subsequent AT/AFL. PMID:27764185

  10. Atrial Substrate Modification in Atrial Fibrillation: Targeting GP or CFAE? Evidence from Meta-Analysis of Clinical Trials.

    PubMed

    Qin, Mu; Liu, Xu; Wu, Shao-Hui; Zhang, Xiao-Dong

    2016-01-01

    Several clinically relevant outcomes post atrial substrate modification in patients with atrial fibrillation (AF) have not been systematically analyzed among published studies on adjunctive cardiac ganglionated plexi (GP) or complex fractionated atrial electograms (CFAE) ablation vs. pulmonary vein isolation (PVI) alone. Out of 176 reports identified, the present meta-analysis included 14 randomized and non-randomized controlled trials (1613 patients) meeting inclusion criteria. Addition of GP ablation to PVI significantly increased freedom from atrial tachyarrhythmia in short- (OR: 1.72; P = 0.003) and long-term (OR: 2.0, P = 0.0006) follow-up, while adjunctive CFAE ablation did not after one or repeat procedure (P<0.05). The percentage of atrial tachycardia or atrial flutter (AT/AFL) after one procedure was higher for CFAE than GP ablation. In sub-analysis of non-paroxysmal AF, relative to PVI alone, adjunctive GP but not CFAE ablation significantly increased sinus rhythm maintenance (OR: 1.88, P = 0.01; and OR:1.24, P = 0.18, respectively). Meta regression analysis of the 14 studies indicated that sample size was significant source of heterogeneity either in outcomes after one or repeat procedure. In conclusion, in patients with AF, adjunctive GP but not CFAE ablation appeared to significantly add to the beneficial effects on sinus rhythm maintenance of PVI ablation alone; and CFAE ablation was associated with higher incidence of subsequent AT/AFL.

  11. [Coating modification of anthracite substrates in vertical-flow constructed wetlands by LDHs synthesized from different metal compounds and the nitrogen removal efficiencies].

    PubMed

    Zhang, Xiang-Ling; Guo, Lu; Chen, Jun-Jie; Liu, Xiao-Ting; Xu, Lu; Chen, Qiao-Zhen; Wang, Xiao-Xiao

    2014-08-01

    As one kind of vertical-flow constructed wetlands substrates, anthracite was selected in this experiment. LDHs (layered double hydroxides) were synthesized in alkaline conditions by co-precipitation of different kinds of metal compounds, such as CaCl2, ZnCl2, MgCl2, FeCl3, AlCl3, CoCl3. The synthesized LDHs were in-situ coated onto the surface of anthracite substrate to achieve the aim of modification. Simulated test columns were constructed to study the nitrogen removal efficiency of the urban sewage using the original anthracite substrates and 9 kinds of modified anthracite substrates. The results showed that: LDHs synthesized by all the 9 different kinds of methods could effectively modify the anthracite substrate by in-situ coating. With Mg2+ involved in the synthesis of modified substrates, good TN and ammonia nitrogen removal efficiencies were observed. The modified anthracite substrates coated with MgCo-LDHs had the optimal performance with average TN and ammonia nitrogen removal efficiencies of higher than 80% and 85%, respectively. The ammonia nitrogen removal efficiencies by the modified anthracite substrates coated by LDHs reacted with Mg2+ and Fe3+ were also high. The ammonia nitrogen removal efficiencies by modified anthracite substrates coated with CaFe-LDHs and MgFe-LDHs were higher than 85%.

  12. Conduction noise absorption by ITO thin films attached to microstrip line utilizing Ohmic loss

    SciTech Connect

    Kim, Sun-Hong; Kim, Sung-Soo

    2010-07-15

    For the aim of wide-band noise absorbers with a special design for low frequency performance, this study proposes conductive indium-tin oxide (ITO) thin films as the absorbent materials in microstrip line. ITO thin films were deposited on the polyimide film substrates by rf magnetron cosputtering of In{sub 2}O{sub 3} and Sn targets. The deposited ITO films show a typical value of electrical resistivity ({approx}10{sup -4} {Omega} m) and sheet resistance can be controlled in the range of 20-230 {Omega} by variation in film thickness. Microstrip line with characteristic impedance of 50 {Omega} was used for determining their noise absorbing properties. It is found that there is an optimum sheet resistance of ITO films for the maximum power absorption. Reflection parameter (S{sub 11}) is increased with decrease in sheet resistance due to impedance mismatch. On the while, transmission parameter (S{sub 21}) is decreased with decrease in sheet resistance due to larger Ohmic loss of the ITO films. Experimental results and computational prediction show that the optimum sheet resistance is about 100 {Omega}. For this film, greater power absorption is predicted in the lower frequency region than ferrite thin films of high magnetic loss, which indicates that Ohmic loss is the predominant loss parameter for power absorption in the low frequency range.

  13. Electrodeposition of gold nanoparticle arrays on ITO glass as electrode with high electrocatalytic activity

    SciTech Connect

    Zhang, Kui; Wei, Juan; Zhu, Houjuan; Ma, Fang; Wang, Suhua

    2013-03-15

    Highlights: ► Electrodeposition of gold nanoparticle arrays on ITO glass as catalytic-electrodes. ► The sizes and densities of the gold nanoparticles can be easily controlled. ► Such arrays on ITO glass shows high electrocatalytic activity and good stability. - Abstract: Herein, we reported a templateless, surfactantless, and simple electrochemical method to directly fabricate gold nanoparticle (AuNP) arrays on indium tin oxide (ITO) glass substrates as effective electrocatalytic electrodes. The as-prepared AuNP arrays have been characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), etc. AuNPs with small sizes (<20 nm) were uniformly deposited on the ITO glass under constant current densities, and particle densities can be adjusted by varying the applied charges. The resultant AuNP array electrode showed higher catalytic activity and good stability toward electro-oxidation of ascorbic acid compared with other electrodes, such as bare ITO electrode, bare glassy carbon electrode and bulk gold film electrode.

  14. In situ Crystallization of RF sputtered ITO thin films: A comparison with annealed samples

    SciTech Connect

    John, K. Aijo; Manju, T.

    2014-01-28

    Tin doped Indium Oxide (ITO) is a wide band gap semiconductor with high conductivity and transparency in the visible region of the solar spectrum. One of the most popular and exploited applications of ITO is the realization of the transparent conductive layers needed for the electrodes of light sensitive devices, such as photovoltaic cells. The thermal energy for the crystallization of ITO films is very low (150°C). The crystallization can be achieved by the continuous energetic bombardment of the ions in the sputtering chamber without annealing or substrate heating. The accumulated energy will ensure the thermal energy necessary for the crystallization. With the help of sufficiently high sputtering power and sufficient duration, crystallized ITO films can be produced without annealing. In this report, a comparison of the conductivity and transparency of ITO films under two crystallization conditions ((1) crystallization of the sputtered films by annealing; (2) in situ crystallization of the films by providing high sputtering power and long sputtering duration) will be presented.

  15. A transparent flexible z-axis sensitive multi-touch panel based on colloidal ITO nanocrystals.

    PubMed

    Sangeetha, N M; Gauvin, M; Decorde, N; Delpech, F; Fazzini, P F; Viallet, B; Viau, G; Grisolia, J; Ressier, L

    2015-08-07

    Bottom-up fabrication of a flexible multi-touch panel prototype based on transparent colloidal indium tin oxide (ITO) nanocrystal (NC) films is presented. A series of 7% Sn(4+) doped ITO NCs protected by oleate, octanoate and butanoate ligands are synthesized and characterized by a battery of techniques including, high resolution transmission electron microscopy, X-ray diffraction, (1)H, (13)C and (119)Sn nuclear magnetic resonance spectroscopy, and the related diffusion ordered spectroscopy. Electrical resistivities of transparent films of these NCs assembled on flexible polyethylene terephthalate substrates by convective self-assembly from their suspension in toluene decrease with the ligand length, from 220 × 10(3) for oleate ITO to 13 × 10(3)Ω cm for butanoate ITO NC films. A highly transparent, flexible touch panel based on a matrix of strain gauges derived from the least resistive film of 17 nm butanoate ITO NCs sensitively detects the lateral position (x, y) of the touch as well as its intensity over the z-axis. Being compatible with a stylus or bare/gloved finger, a larger version of this module may be readily implemented in upcoming flexible screens, enabling navigation capabilities over all three axes, a feature highly desired by the display industry.

  16. dbPTM 3.0: an informative resource for investigating substrate site specificity and functional association of protein post-translational modifications

    PubMed Central

    Lu, Cheng-Tsung; Huang, Kai-Yao; Su, Min-Gang; Lee, Tzong-Yi; Bretaña, Neil Arvin; Chang, Wen-Chi; Chen, Yi-Ju; Chen, Yu-Ju; Huang, Hsien-Da

    2013-01-01

    Protein modification is an extremely important post-translational regulation that adjusts the physical and chemical properties, conformation, stability and activity of a protein; thus altering protein function. Due to the high throughput of mass spectrometry (MS)-based methods in identifying site-specific post-translational modifications (PTMs), dbPTM (http://dbPTM.mbc.nctu.edu.tw/) is updated to integrate experimental PTMs obtained from public resources as well as manually curated MS/MS peptides associated with PTMs from research articles. Version 3.0 of dbPTM aims to be an informative resource for investigating the substrate specificity of PTM sites and functional association of PTMs between substrates and their interacting proteins. In order to investigate the substrate specificity for modification sites, a newly developed statistical method has been applied to identify the significant substrate motifs for each type of PTMs containing sufficient experimental data. According to the data statistics in dbPTM, >60% of PTM sites are located in the functional domains of proteins. It is known that most PTMs can create binding sites for specific protein-interaction domains that work together for cellular function. Thus, this update integrates protein–protein interaction and domain–domain interaction to determine the functional association of PTM sites located in protein-interacting domains. Additionally, the information of structural topologies on transmembrane (TM) proteins is integrated in dbPTM in order to delineate the structural correlation between the reported PTM sites and TM topologies. To facilitate the investigation of PTMs on TM proteins, the PTM substrate sites and the structural topology are graphically represented. Also, literature information related to PTMs, orthologous conservations and substrate motifs of PTMs are also provided in the resource. Finally, this version features an improved web interface to facilitate convenient access to the resource

  17. A transparent flexible z-axis sensitive multi-touch panel based on colloidal ITO nanocrystals

    NASA Astrophysics Data System (ADS)

    Sangeetha, N. M.; Gauvin, M.; Decorde, N.; Delpech, F.; Fazzini, P. F.; Viallet, B.; Viau, G.; Grisolia, J.; Ressier, L.

    2015-07-01

    Bottom-up fabrication of a flexible multi-touch panel prototype based on transparent colloidal indium tin oxide (ITO) nanocrystal (NC) films is presented. A series of 7% Sn4+ doped ITO NCs protected by oleate, octanoate and butanoate ligands are synthesized and characterized by a battery of techniques including, high resolution transmission electron microscopy, X-ray diffraction, 1H, 13C and 119Sn nuclear magnetic resonance spectroscopy, and the related diffusion ordered spectroscopy. Electrical resistivities of transparent films of these NCs assembled on flexible polyethylene terephthalate substrates by convective self-assembly from their suspension in toluene decrease with the ligand length, from 220 × 103 for oleate ITO to 13 × 103 Ω cm for butanoate ITO NC films. A highly transparent, flexible touch panel based on a matrix of strain gauges derived from the least resistive film of 17 nm butanoate ITO NCs sensitively detects the lateral position (x, y) of the touch as well as its intensity over the z-axis. Being compatible with a stylus or bare/gloved finger, a larger version of this module may be readily implemented in upcoming flexible screens, enabling navigation capabilities over all three axes, a feature highly desired by the display industry.Bottom-up fabrication of a flexible multi-touch panel prototype based on transparent colloidal indium tin oxide (ITO) nanocrystal (NC) films is presented. A series of 7% Sn4+ doped ITO NCs protected by oleate, octanoate and butanoate ligands are synthesized and characterized by a battery of techniques including, high resolution transmission electron microscopy, X-ray diffraction, 1H, 13C and 119Sn nuclear magnetic resonance spectroscopy, and the related diffusion ordered spectroscopy. Electrical resistivities of transparent films of these NCs assembled on flexible polyethylene terephthalate substrates by convective self-assembly from their suspension in toluene decrease with the ligand length, from 220 × 103 for

  18. Comparative study of ITO and TiN fabricated by low-temperature RF biased sputtering

    SciTech Connect

    Simon, Daniel K. Schenk, Tony; Dirnstorfer, Ingo; Fengler, Franz P. G.; Jordan, Paul M.; Krause, Andreas; Tröger, David; Mikolajick, Thomas

    2016-03-15

    Radio frequency (RF) biasing induced by a second plasma source at the substrate is applied to low-temperature sputtering processes for indium tin oxide (ITO) and titanium nitride (TiN) thin films. Investigations on crystal structure and surface morphology show that RF-biased substrate plasma processes result in a changed growth regime with different grain sizes and orientations than those produced by processes without a substrate bias. The influence of the RF bias is shown comparatively for reactive RF-sputtered ITO and reactive direct-current-sputtered TiN. The ITO layers exhibit an improved electrical resistivity of 0.5 mΩ cm and an optical absorption coefficient of 0.5 × 10{sup 4 }cm{sup −1} without substrate heating. Room-temperature sputtered TiN layers are deposited that possess a resistivity (0.1 mΩ cm) of 3 orders of magnitude lower than, and a density (5.4 g/cm{sup 3}) up to 45% greater than, those obtained from layers grown using the standard process without a substrate plasma.

  19. Novel Protein Substrates of the Phospho-Form Modification System in Neisseria gonorrhoeae and Their Connection to O-Linked Protein Glycosylation

    PubMed Central

    Anonsen, Jan Haug; Egge-Jacobsen, Wolfgang; Aas, Finn Erik; Børud, Bente; Koomey, Michael

    2012-01-01

    The zwitterionic phospho-form moieties phosphoethanolamine (PE) and phosphocholine (PC) are important components of bacterial membranes and cell surfaces. The major type IV pilus subunit protein of Neisseria gonorrhoeae, PilE, undergoes posttranslational modifications with these moieties via the activity of the pilin phospho-form transferase PptA. A number of observations relating to colocalization of phospho-form and O-linked glycan attachment sites in PilE suggested that these modifications might be either functionally or mechanistically linked or interact directly or indirectly. Moreover, it was unknown whether the phenomenon of phospho-form modification was solely dedicated to PilE or if other neisserial protein targets might exist. In light of these concerns, we screened for evidence of phospho-form modification on other membrane glycoproteins targeted by the broad-spectrum O-linked glycosylation system. In this way, two periplasmic lipoproteins, NGO1043 and NGO1237, were identified as substrates for PE addition. As seen previously for PilE, sites of PE modifications were clustered with those of glycan attachment. In the case of NGO1043, evidence for at least six serine phospho-form attachment sites was found, and further analyses revealed that at least two of these serines were also attachment sites for glycan. Finally, mutations altering glycosylation status led to the presence of pptA-dependent PC modifications on both proteins. Together, these results reinforce the associations established in PilE and provide evidence for dynamic interplay between phospho-form modification and O-linked glycosylation. The observations also suggest that phospho-form modifications likely contribute biologically at both intracellular and extracellular levels. PMID:22083701

  20. Initial stages of ITO/Si interface formation: In situ x-ray photoelectron spectroscopy measurements upon magnetron sputtering and atomistic modelling using density functional theory

    SciTech Connect

    Løvvik, O. M.; Diplas, S.; Ulyashin, A.; Romanyuk, A.

    2014-02-28

    Initial stages of indium tin oxide (ITO) growth on a polished Si substrate upon magnetron sputtering were studied experimentally using in-situ x-ray photoelectron spectroscopy measurements. The presence of pure indium and tin, as well as Si bonded to oxygen at the ITO/Si interface were observed. The experimental observations were compared with several atomistic models of ITO/Si interfaces. A periodic model of the ITO/Si interface was constructed, giving detailed information about the local environment at the interface. Molecular dynamics based on density functional theory was performed, showing how metal-oxygen bonds are broken on behalf of silicon-oxygen bonds. These theoretical results support and provide an explanation for the present as well as previous ex-situ and in-situ experimental observations pointing to the creation of metallic In and Sn along with the growth of SiO{sub x} at the ITO/Si interface.

  1. Anodization of Ti thin film deposited on ITO.

    PubMed

    Sadek, Abu Z; Zheng, Haidong; Latham, Kay; Wlodarski, Wojtek; Kalantar-Zadeh, Kourosh

    2009-01-06

    We have investigated several key aspects for the self-organization of nanotubes in RF sputtered titanium (Ti) thin films formed by the anodization process in fluoride-ion-containing neutral electrolytes. Ti films were deposited on indium tin oxide (ITO) glass substrates at room temperature and 300 degrees C, and then anodized. The films were studied using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis spectrometry before and after anodization. It was observed that anodization of high temperature deposited films resulted in nanotube type structures with diameters in the range of 10-45 nm for an applied voltage of 5-20 V. In addition, the anatase form of TiO(2) is formed during the anodization process which is also confirmed using photocurrent measurements. However, the anodization of room temperature deposited Ti films resulted in irregular pores or holes.

  2. Electrical and optical properties of near UV transparent conductive ITO/Ga2O3 multilayer films deposited by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Kwan; Lee, Ji-Myon

    2016-10-01

    Ga2O3/ITO co-sputtering and alternating multilayer films were deposited on the Corning glass substrates by radio frequency magnetron technique at room temperature. We investigated the effects of the thickness and period of Ga2O3 interlayer on the microstructure. We also elucidated the electrical and the optical properties of Ga2O3/indium tin oxide (ITO) multilayer films and co-sputtered the Ga2O3/ITO mixed films (co-IGTO). One-period Ga2O3/ITO films, which exhibited the lowest sheet resistance of 58.6 Ω/sq and the highest transmittance of 80.94% at a wavelength of 380 nm, were deposited on the Corning glass. The sheet resistance of co-sputtered Ga2O3/ITO film was rapidly increased to 189.2 Ω/sq., while the Hall mobility of the same film was rapidly decreased to 12.53 cm2/(V s). Although the carrier concentration of the multilayer films was lower than that of the ITO single layer, the figure of merit of the Ga2O3/ITO one-period alternating multilayer films was higher than those of single ITO and co-IGTO films.

  3. Sensitivity of CuS and CuS/ITO EGFETs implemented as pH sensors

    NASA Astrophysics Data System (ADS)

    Sabah, Fayroz A.; Ahmed, Naser M.; Hassan, Z.; Al-Hardan, Naif H.

    2016-09-01

    Several studies have been performed on the use of ITO as an extended gate of field effect transistor. Studies have also been done on the effects of using ITO as a substrate to improve the sensitivity of SnO2 membrane. In this research, the ITO was used as a substrate for the synthesis of CuS thin films to determine its potential to improve sensitivity and any possible application as pH sensors. The CuS thin film was prepared from copper chloride and sodium thiosulfate via spray pyrolysis deposition using de-ionized water as a solvent. The sensitivity of the CuS/ITO membrane was measured and comparatively analyzed against that of CuS membrane. Structural and morphological properties were investigated for both as-deposit thin films. The membranes were then deployed as pH sensors and their sensitivities measured. The results confirmed that CuS/ITO membrane had much better sensitivity (37 µA/pH and 37 mV/pH) compared to CuS membrane (8 µA/pH and 7.5 mV/pH).

  4. c-Myc alters substrate utilization and O-GlcNAc protein posttranslational modifications without altering cardiac function during early aortic constriction

    SciTech Connect

    Ledee, Dolena; Smith, Lincoln; Bruce, Margaret; Kajimoto, Masaki; Isern, Nancy; Portman, Michael A.; Olson, Aaron K.; Bertrand, Luc

    2015-08-12

    Pressure overload cardiac hypertrophy alters substrate metabolism. Prior work showed that myocardial inactivation of c-Myc (Myc) attenuated hypertrophy and decreased expression of metabolic genes after aortic constriction. Accordingly, we hypothesize that Myc regulates substrate preferences for the citric acid cycle during pressure overload hypertrophy from transverse aortic constriction (TAC) and that these metabolic changes impact cardiac function and growth. To test this hypothesis, we subjected mice with cardiac specific, inducible Myc inactivation (MycKO-TAC) and non-transgenic littermates (Cont-TAC) to transverse aortic constriction (TAC; n=7/group). A separate group underwent sham surgery (Sham, n=5). After two weeks, function was measured in isolated working hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketone bodies and unlabeled glucose and insulin. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. Compared to Sham, Cont-TAC had increased free fatty acid fractional contribution with a concurrent decrease in unlabeled (predominately glucose) contribution. The changes in free fatty acid and unlabeled fractional contributions were abrogated by Myc inactivation during TAC (MycKO-TAC). Additionally, protein posttranslational modification by O-GlcNAc was significantly greater in Cont-TAC versus both Sham and MycKO-TAC. Lastly, Myc alters substrate preferences for the citric acid cycle during early pressure overload hypertrophy without negatively affecting cardiac function. Myc also affects protein posttranslational modifications by O-GlcNAc during hypertrophy.

  5. c-Myc Alters Substrate Utilization and O-GlcNAc Protein Posttranslational Modifications without Altering Cardiac Function during Early Aortic Constriction

    PubMed Central

    Ledee, Dolena; Smith, Lincoln; Bruce, Margaret; Kajimoto, Masaki; Isern, Nancy; Portman, Michael A.; Olson, Aaron K.

    2015-01-01

    Hypertrophic stimuli cause transcription of the proto-oncogene c-Myc (Myc). Prior work showed that myocardial knockout of c-Myc (Myc) attenuated hypertrophy and decreased expression of metabolic genes after aortic constriction. Accordingly, we assessed the interplay between Myc, substrate oxidation and cardiac function during early pressure overload hypertrophy. Mice with cardiac specific, inducible Myc knockout (MycKO-TAC) and non-transgenic littermates (Cont-TAC) were subjected to transverse aortic constriction (TAC; n = 7/group). Additional groups underwent sham surgery (Cont-Sham and MycKO-Sham, n = 5 per group). After two weeks, function was measured in isolated working hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketone bodies and unlabeled glucose and insulin. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. In sham hearts, Myc knockout did not affect cardiac function or substrate preferences for the citric acid cycle. However, Myc knockout altered fractional contributions during TAC. The unlabeled fractional contribution increased in MycKO-TAC versus Cont-TAC, whereas ketone and free fatty acid fractional contributions decreased. Additionally, protein posttranslational modifications by O-GlcNAc were significantly greater in Cont-TAC versus both Cont-Sham and MycKO-TAC. In conclusion, Myc alters substrate preferences for the citric acid cycle during early pressure overload hypertrophy without negatively affecting cardiac function. Myc also affects protein posttranslational modifications by O-GlcNAc during hypertrophy, which may regulate Myc-induced metabolic changes. PMID:26266538

  6. c-Myc alters substrate utilization and O-GlcNAc protein posttranslational modifications without altering cardiac function during early aortic constriction

    DOE PAGES

    Ledee, Dolena; Smith, Lincoln; Bruce, Margaret; ...

    2015-08-12

    Pressure overload cardiac hypertrophy alters substrate metabolism. Prior work showed that myocardial inactivation of c-Myc (Myc) attenuated hypertrophy and decreased expression of metabolic genes after aortic constriction. Accordingly, we hypothesize that Myc regulates substrate preferences for the citric acid cycle during pressure overload hypertrophy from transverse aortic constriction (TAC) and that these metabolic changes impact cardiac function and growth. To test this hypothesis, we subjected mice with cardiac specific, inducible Myc inactivation (MycKO-TAC) and non-transgenic littermates (Cont-TAC) to transverse aortic constriction (TAC; n=7/group). A separate group underwent sham surgery (Sham, n=5). After two weeks, function was measured in isolated workingmore » hearts along with substrate fractional contributions to the citric acid cycle by using perfusate with 13C labeled mixed fatty acids, lactate, ketone bodies and unlabeled glucose and insulin. Cardiac function was similar between groups after TAC although +dP/dT and -dP/dT trended towards improvement in MycKO-TAC versus Cont-TAC. Compared to Sham, Cont-TAC had increased free fatty acid fractional contribution with a concurrent decrease in unlabeled (predominately glucose) contribution. The changes in free fatty acid and unlabeled fractional contributions were abrogated by Myc inactivation during TAC (MycKO-TAC). Additionally, protein posttranslational modification by O-GlcNAc was significantly greater in Cont-TAC versus both Sham and MycKO-TAC. Lastly, Myc alters substrate preferences for the citric acid cycle during early pressure overload hypertrophy without negatively affecting cardiac function. Myc also affects protein posttranslational modifications by O-GlcNAc during hypertrophy.« less

  7. Surface modification of a-plane sapphire substrates and its effect on crystal orientation of ZnTe layer

    NASA Astrophysics Data System (ADS)

    Nakasu, Taizo; Sun, Wei-Che; Kobayashi, Masakazu

    2017-01-01

    Domain structures of ZnTe layers grown on a-plane sapphire substrates were investigated by changing the crystallographic properties of the surface and interface. Pole figure images were obtained and we investigated the domain structure in the grown film and the orientation relationships between films and substrates. It was confirmed that two kinds of {111} domains were oriented by annealing the buffer layer at 350 °C, while the (100) domain was obtained by annealing the buffer layer at 300 °C. From the results of the rocking curve measurement, the introduction of a step-terrace surface through the high-temperature treatment of the substrate resulted in an improved crystallographic quality. However, it did not affect the domain structure in the layer. The introduction of an off-angle on the substrate surface resulted in the formation of a single (111) domain layer. These crystallographic features were mainly affected by the surface atom arrangement of the sapphire substrate and its chemical nature.

  8. Interface modification and material synthesis of organic light-emitting diodes using plasma technology

    NASA Astrophysics Data System (ADS)

    Liang, Rongqing; Ou, Qiongrong; Yang, Cheng; He, Kongduo; Yang, Xilu; Zhong, Shaofeng; plasma application Team

    2015-09-01

    Organic light-emitting diodes (OLEDs), due to their unique properties of solution processability, compatibility with flexible substrates and with large-scale printing technology, attract huge interest in the field of lighting. The integration of plasma technology into OLEDs provides a new route to improve their performance. Here we demonstrate the modification of indium-tin-oxide (ITO) work function by plasma treatment, synthesis of thermally activated delayed fluorescence (TADF) materials using plasma grafting (polymerisation), and multi-layer solution processing achieved by plasma cross-linking.

  9. ITOS D AND E system design report, volume 1

    NASA Technical Reports Server (NTRS)

    1970-01-01

    The configuration and functions of the ITOS D and E system are described. The system will expand the operational capability of the basic TIROS M/ITOS system. The ITOS D and E mission will utilize the capabilities of the two-stage DSV 3N-6 Delta launch vehicle to place the ITOS D and E spacecraft into a circular, near-polar, sun synchronous orbit at 790 nautical miles altitude. The ITOS D and E will provide the following primary data: (1) visible daytime observations of cloud cover, (2) daytime and nighttime observations of cloud cover as detected from radiance in infrared spectrum, and (3) vertical temperature profile of the atmosphere on a global basis for data processing. In addition, the ITOS D and E system will provide secondary data comprising solar proton density measurements obtained throughout the orbit.

  10. Satellite technology. [Landsat 1 and ITOS

    NASA Technical Reports Server (NTRS)

    Branchflower, G. A.

    1974-01-01

    An exposure to satellite design and fabrication techniques used in unmanned satellite programs is provided. Spacecraft configurations of the earth resources technology satellite (ERTS) and the improved ITOS operational satellite, which are typical of the construction and layout techniques presently in use, are discussed. Support and service subsystems are described taking the ERTS subsystems as representative. The subsystems explained comprise: power, attitude control, orbit adjustment, wideband telemetry, tracking-telemetry-command, auxiliary processing, electrical integration, and spaceborne recording devices. A number of photographs, renditions and diagrams illustrates the text.

  11. Modification of fluorous substrates with oligo(ethylene glycol) via "click" chemistry for long-term resistance of cell adhesion.

    PubMed

    Contreras-Caceres, Rafael; Santos, Catherine M; Li, Siheng; Kumar, Amit; Zhu, Zhiling; Kolar, Satya S; Casado-Rodriguez, Miguel A; Huang, Yongkai; McDermott, Alison; Lopez-Romero, Juan Manuel; Cai, Chengzhi

    2015-11-15

    In this work perfluorinated substrates fabricated from SiO2 glass slides are modified with oligo(ethylene glycol) (OEG) units for long-term resistance of cell adhesion purposes, based on fluorous interactions and click chemistry. Specifically, fluorous substrates, prepared by treatment of glass slides with 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane (FAS17), were coated with ethynyl-OEG-C8F17, followed by covalent attachment of an azido-OEG via copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reaction. We demonstrate that the resultant surface avoid fibrinogen adsorption and resisted cell adhesion for over 14days. X-ray photoemission spectroscopy (XPS) analysis and contact angle goniometry measurements confirm the presence of the OEG molecules on the fluorous substrates. Bright field optical images show total absence of 3T3 fibroblast cells on the OEG modified fluorinated substrate for 1 and 5days, and a remarkably decrease of cell adhesion at 14days.

  12. ITO-MgF2 Film Development for PowerSphere Polymer Surface Protection

    NASA Technical Reports Server (NTRS)

    Hambourger, Paul D.; Kerslake, Thomas W.; Waters, Deborah L.

    2004-01-01

    Multi-kilogram class microsatellites with a PowerSphere electric power system are attractive for fulfilling a variety of potential NASA missions. However, PowerSphere polymer surfaces must be coated with a film that has suitable electrical sheet resistivity for electrostatic discharge control, be resistant to atomic oxygen attack, be transparent to ultraviolet light for composite structure curing and resist ultraviolet light induced darkening for efficient photovoltaic cell operation. In addition, the film must be tolerant of polymer layer folding associated with launch stowage of PowerSphere inflatable structures. An excellent film material candidate to meet these requirements is co-sputtered, indium oxide (In2O3) - tin oxide (SnO2), known as 'ITO', and magnesium fluoride (MgF2). While basic ITO-MgF2 film properties have been the subject of research over the last decade, further research is required in the areas of film durability for space-inflatable applications and precise film property control for large scale commercial production. In this paper, the authors present film durability results for a folded polymer substrate and film resistance to vacuum UV darkening. The authors discuss methods and results in the area of film sheet resistivity measurement and active control, particularly dual-channel, plasma emission line measurement of ITO and MgF2 plasma sources. ITO-MgF2 film polymer coupon preparation is described as well as film deposition equipment, procedures and film characterization. Durability testing methods are also described. The pre- and post-test condition of the films is assessed microscopically and electrically. Results show that an approx. 500A ITO-18vol% MgF2 film is a promising candidate to protect PowerSphere polymer surfaces for Earth orbit missions. Preliminary data also indicate that in situ film measurement methods are promising for active film resistivity control in future large scale production. Future film research plans are also

  13. Monitoring of dopamine release in single cell using ultrasensitive ITO microsensors modified with carbon nanotubes.

    PubMed

    Shi, Bao-Xian; Wang, Yu; Zhang, Kai; Lam, Tin-Lun; Chan, Helen Lai-Wa

    2011-02-15

    The study of single cell dynamics has been greatly adapted in biological and medical research and applications. In this work a novel microfluidic electrochemical sensor with carbon nanotubes (CNTs) modified indium tin oxide (ITO) microelectrode was developed for single cells release monitoring. The sensitivity of the electrochemical sensor after CNTs surface modification was improved by 2.5-3 orders of magnitude. The developed CNTs modified ITO sensor was successfully employed to monitor the dopamine release from single living rat pheochromocytoma (PC 12) cells. Its ultrahigh sensitivity, transparency and need for fewer agents enable this smart electrochemical sensor to become a powerful tool in recording dynamic release from various living tissues and organs optically and electrically.

  14. Insights into the Activity and Substrate Binding of Xylella fastidiosa Polygalacturonase by Modification of a Unique QMK Amino Acid Motif Using Protein Chimeras

    PubMed Central

    Warren, Jeremy G.; Lincoln, James E.; Kirkpatrick, Bruce C.

    2015-01-01

    Polygalacturonases (EC 3.2.1.15) catalyze the random hydrolysis of 1, 4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. Xylella fastidiosa possesses a single polygalacturonase gene, pglA (PD1485), and X. fastidiosa mutants deficient in the production of polygalacturonase are non-pathogenic and show a compromised ability to systemically infect grapevines. These results suggested that grapevines expressing sufficient amounts of an inhibitor of X. fastidiosa polygalacturonase might be protected from disease. Previous work in our laboratory and others have tried without success to produce soluble active X. fastidiosa polygalacturonase for use in inhibition assays. In this study, we created two enzymatically active X. fastidiosa / A. vitis polygalacturonase chimeras, AX1A and AX2A to explore the functionality of X. fastidiosa polygalacturonase in vitro. The AX1A chimera was constructed to specifically test if recombinant chimeric protein, produced in Escherichia coli, is soluble and if the X. fastidiosa polygalacturonase catalytic amino acids are able to hydrolyze polygalacturonic acid. The AX2A chimera was constructed to evaluate the ability of a unique QMK motif of X. fastidiosa polygalacturonase, most polygalacturonases have a R(I/L)K motif, to bind to and allow the hydrolysis of polygalacturonic acid. Furthermore, the AX2A chimera was also used to explore what effect modification of the QMK motif of X. fastidiosa polygalacturonase to a conserved RIK motif has on enzymatic activity. These experiments showed that both the AX1A and AX2A polygalacturonase chimeras were soluble and able to hydrolyze the polygalacturonic acid substrate. Additionally, the modification of the QMK motif to the conserved RIK motif eliminated hydrolytic activity, suggesting that the QMK motif is important for the activity of X. fastidiosa polygalacturonase. This result suggests X. fastidiosa polygalacturonase may preferentially hydrolyze a different pectic substrate or

  15. Insights into the Activity and Substrate Binding of Xylella fastidiosa Polygalacturonase by Modification of a Unique QMK Amino Acid Motif Using Protein Chimeras.

    PubMed

    Warren, Jeremy G; Lincoln, James E; Kirkpatrick, Bruce C

    2015-01-01

    Polygalacturonases (EC 3.2.1.15) catalyze the random hydrolysis of 1, 4-alpha-D-galactosiduronic linkages in pectate and other galacturonans. Xylella fastidiosa possesses a single polygalacturonase gene, pglA (PD1485), and X. fastidiosa mutants deficient in the production of polygalacturonase are non-pathogenic and show a compromised ability to systemically infect grapevines. These results suggested that grapevines expressing sufficient amounts of an inhibitor of X. fastidiosa polygalacturonase might be protected from disease. Previous work in our laboratory and others have tried without success to produce soluble active X. fastidiosa polygalacturonase for use in inhibition assays. In this study, we created two enzymatically active X. fastidiosa / A. vitis polygalacturonase chimeras, AX1A and AX2A to explore the functionality of X. fastidiosa polygalacturonase in vitro. The AX1A chimera was constructed to specifically test if recombinant chimeric protein, produced in Escherichia coli, is soluble and if the X. fastidiosa polygalacturonase catalytic amino acids are able to hydrolyze polygalacturonic acid. The AX2A chimera was constructed to evaluate the ability of a unique QMK motif of X. fastidiosa polygalacturonase, most polygalacturonases have a R(I/L)K motif, to bind to and allow the hydrolysis of polygalacturonic acid. Furthermore, the AX2A chimera was also used to explore what effect modification of the QMK motif of X. fastidiosa polygalacturonase to a conserved RIK motif has on enzymatic activity. These experiments showed that both the AX1A and AX2A polygalacturonase chimeras were soluble and able to hydrolyze the polygalacturonic acid substrate. Additionally, the modification of the QMK motif to the conserved RIK motif eliminated hydrolytic activity, suggesting that the QMK motif is important for the activity of X. fastidiosa polygalacturonase. This result suggests X. fastidiosa polygalacturonase may preferentially hydrolyze a different pectic substrate or

  16. Probing the promiscuous active site of myo-inositol dehydrogenase using synthetic substrates, homology modeling, and active site modification.

    PubMed

    Daniellou, Richard; Zheng, Hongyan; Langill, David M; Sanders, David A R; Palmer, David R J

    2007-06-26

    The active site of myo-inositol dehydrogenase (IDH, EC 1.1.1.18) from Bacillus subtilis recognizes a variety of mono- and disaccharides, as well as 1l-4-O-substituted inositol derivatives. It catalyzes the NAD+-dependent oxidation of the axial alcohol of these substrates with comparable kinetic constants. We have found that 4-O-p-toluenesulfonyl-myo-inositol does not act as a substrate for IDH, in contrast to structurally similar compounds such as those bearing substituted benzyl substituents in the same position. X-ray crystallographic analysis of 4-O-p-toluenesulfonyl-myo-inositol and 4-O-(2-naphthyl)methyl-myo-inositol, which is a substrate for IDH, shows a distinct difference in the preferred conformation of the aryl substituent. Conformational analysis of known substrates of IDH suggests that this conformational difference may account for the difference in reactivity of 4-O-p-toluenesulfonyl-myo-inositol in the presence of IDH. A sequence alignment of IDH with the homologous glucose-fructose oxidoreductase allowed the construction of an homology model of inositol dehydrogenase, to which NADH and 4-O-benzyl-scyllo-inosose were docked and the active site energy minimized. The active site model is consistent with all experimental results and suggests that a conserved tyrosine-glycine-tyrosine motif forms the hydrophobic pocket adjoining the site of inositol recognition. Y233F and Y235F retain activity, while Y233R and Y235R do not. A histidine-aspartate pair, H176 and D172, are proposed to act as a dyad in which H176 is the active site acid/base. The enzyme is inactivated by diethyl pyrocarbonate, and the mutants H176A and D172N show a marked loss of activity. Kinetic isotope effect experiments with D172N indicate that chemistry is rate-determining for this mutant.

  17. Electrochemically-deposited ZnO nanorods arrays on ITO seeding layers

    NASA Astrophysics Data System (ADS)

    Petrov, M.; Lovchinov, K.; Nichev, H.; Dimova-Malinovska, D.

    2016-03-01

    In this paper, results are reported from the study of the structural and optical properties of ZnO nanostructured arrays with nanorods (NRs) grown electrochemically on ITO seeding layers with two different thicknesses deposited on a glass substrate. The properties are compared of the ZnO NRs grown on ITO seeding layers with resistivity 6.4 × 10-4 Ω cm, sheet resistance 80 Ω/□ and 8 Ω/□ and different ITO thicknesses - 80 and 800 nm, respectively. The optical spectra of reflectance, transmittance, diffused reflection and diffused transmission and the haze ratio in transmission and reflection of the samples carried out before and after ZnO NRs deposition are compared and discussed. The structures' properties are studied by scanning electron microscopy (SEM). The ZnO NRs arrays with increased values of diffused transmission and reflection compared to the seeding layer substrates can be used in thin-film solar cells for increasing the light trapping.

  18. Surface modification of titanium substrates with silver nanoparticles embedded sulfhydrylated chitosan/gelatin polyelectrolyte multilayer films for antibacterial application.

    PubMed

    Li, Wen; Xu, Dawei; Hu, Yan; Cai, Kaiyong; Lin, Yingcheng

    2014-06-01

    To develop Ti implants with potent antibacterial activity, a novel "sandwich-type" structure of sulfhydrylated chitosan (Chi-SH)/gelatin (Gel) polyelectrolyte multilayer films embedding silver (Ag) nanoparticles was coated onto titanium substrate using a spin-assisted layer-by-layer assembly technique. Ag ions would be enriched in the polyelectrolyte multilayer films via the specific interactions between Ag ions and -HS groups in Chi-HS, thus leading to the formation of Ag nanoparticles in situ by photo-catalytic reaction (ultraviolet irradiation). Contact angle measurement and field emission scanning electron microscopy equipped with energy dispersive X-ray spectroscopy were employed to monitor the construction of Ag-containing multilayer on titanium surface, respectively. The functional multilayered films on titanium substrate [Ti/PEI/(Gel/Chi-SH/Ag) n /Gel] could efficiently inhibit the growth and activity of Bacillus subtitles and Escherichia coli onto titanium surface. Moreover, studies in vitro confirmed that Ti substrates coating with functional multilayer films remained the biological functions of osteoblasts, which was reflected by cell morphology, cell viability and ALP activity measurements. This study provides a simple, versatile and generalized methodology to design functional titanium implants with good cyto-compatibility and antibacterial activity for potential clinical applications.

  19. Large-area flexible monolithic ITO/WO3/Nb2O5/NiVOχ/ITO electrochromic devices prepared by using magnetron sputter deposition

    NASA Astrophysics Data System (ADS)

    Tang, Chien-Jen; Ye, Jia-Ming; Yang, Yueh-Ting; He, Ju-Liang

    2016-05-01

    Electrochromic devices (ECDs) have been applied in smart windows to control the transmission of sunlight in green buildings, saving up to 40-50% electricity consumption and ultimately reducing carbon dioxide emissions. However, the high manufacturing costs and difficulty of transportation of conventional massive large area ECDs has limited widespread applications. A unique design replacing the glass substrate commonly used in the ECD windows with inexpensive, light-weight and flexible polymeric substrate materials would accelerate EC adoption allowing them to be supplemented for regular windows without altering window construction. In this study, an ITO/WO3/Nb2O5/NiVOχ/ITO all-solid-state monolithic ECD with an effective area of 24 cm × 18 cm is successfully integrated on a PET substrate by using magnetron sputter deposition. The electrochromic performance and bending durability of the resultant material are also investigated. The experimental results indicate that the ultimate response times for the prepared ECD is 6 s for coloring at an applied voltage of -3 V and 5 s for bleaching at an applied voltage of +3 V, respectively. The optical transmittances for the bleached and colored state at a wavelength of 633 nm are 53% and 11%, respectively. The prepared ECD can sustain over 8000 repeated coloring and bleaching cycles, as well as tolerate a bending radius of curvature of 7.5 cm.

  20. Gradual thickness change of CuPc on MoOx on Oxygen Plasma Treated ITO

    NASA Astrophysics Data System (ADS)

    Wang, Chenggong; Irfan, Irfan; Gao, Yongli

    2012-02-01

    The thickness dependence of copper phthalocyanine (CuPc) interlayer on molybdenum trioxide (MoO3) and conducting indium tin oxide (ITO) has been investigated with ultraviolet photoemission spectroscopy (UPS). We also investigated the air exposure effect on the CuPc/MoO3/ITO interlayers. It was found that the MoO3 interlayer substantially increased the substrate work function (WF). With the deposition of CuPc the WF decreased and saturated at the thickness of 80 å. We also found that 3x10^6 Langmuir (L) air exposure decreased both the MoO3 WF and the interface dipole between CuPc/MoO3 interface.

  1. Surface modification of amorphous substrates by disulfide derivatives: A photo-assisted route to direct functionalization of chalcogenide glasses

    NASA Astrophysics Data System (ADS)

    Amalric, Julien; Marchand-Brynaert, Jacqueline

    2011-12-01

    A novel route for chalcogenide glass surface modification is disclosed. The formation of an organic monolayer from disulfide derivatives is studied on two different glasses of formula GexAsySez by water contact angle measurement, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR). The potential anchoring group is the disulfide functionality. Since thioctic acid derivatives absorb around 335 nm, an irradiation step is included, in order to favor S-S disruption. Three types of disulfide compounds are grafted onto small glass breaks for contact angle and XPS analyses. The results show effective changes of surface state. According to contact angle measurement, the deposited organic layer functionalized by a small polyethylene glycol chain leads to a more hydrophilic surface, long alkyl chain or a perfluorinated carbon chain leads to a more hydrophobic surface. XPS shows the presence at the surface of an organic layer with sulfur and ethylene oxide chains, or augmentation of organic carbons or fluorine and Csbnd F bonds. The photo-assisted grafting of the disulfides onto an ATR prism made of chalcogenide glass shows that this surface modification process does not affect infrared transparency, despite UV treatment, and accurate structural analysis can be performed.

  2. Modification of bovine heart succinate dehydrogenase with ethoxyformic anhydride and rose bengal: evidence for essential histidyl residues protectable by substrates.

    PubMed

    Hederstedt, L; Hatefi, Y

    1986-06-01

    Purified and membrane-bound succinate dehydrogenase (SDH) from bovine heart mitochondria was inhibited by the histidine-modifying reagents ethoxyformic anhydride (EFA) and Rose Bengal in the presence of light. Succinate and competitive inhibitors protected against inhibition, and decreased the number of histidyl residues modified by EFA. The essential residue modified by EFA was not the essential thiol of SDH, but modification of the essential thiol abolished the protective effect of malonate against inhibition of SDH by EFA. The EFA inhibition was reversed by hydroxylamine nearly completely when the inhibition was less than or equal to 35%, and only partially when the inhibition was more extensive. The uv spectrum of EFA-modified SDH before and after hydroxylamine treatment suggested that extensive inhibition of SDH with EFA may result in ethoxyformylation at both imidazole nitrogens of histidyl residues. Such a modification is not reversed by hydroxylamine. Succinate dehydrogenases and fumarate reductases from several different sources have similar compositions, and the two enzymes from Escherichia coli have considerable homology in the amino acid composition of their respective flavoprotein and iron-sulfur protein subunits. In the former, there is a short stretch containing conserved histidine, cysteine, and arginine residues. These residues, if also conserved in the bovine enzyme, may be the essential active site residues suggested by this work (histidine) and previously (cysteine, arginine).

  3. A Sensitive Microplate Assay for Lipase Activity Measurement Using Olive Oil Emulsion Substrate: Modification of the Copper Soap Colorimetric Method.

    PubMed

    Mustafa, Ahmad; Karmali, Amin; Abdelmoez, Wael

    2016-01-01

    The present work involves a sensitive high-throughput microtiter plate based colorimetric assay for estimating lipase activity using cupric acetate pyridine reagent (CAPR). In the first approach, three factors two levels factorial design methodology was used to evaluate the interactive effect of different parameters on the sensitivity of the assay method. The optimization study revealed that the optimum CAPR concentration was 7.5% w/v, the optimum solvent was heptane and the optimum CAPR pH was 6. In the second approach, the optimized colorimetric microplate assay was used to measure lipase activity based on enzymatic hydrolysis of olive oil emulsion substrate at 37°C and 150 rpm. The emulsion substrates were formulated by using olive oil, triton X-100 (10% v/v in pH 8) and sodium phosphate buffer of pH 8 in ratio of 1:1:1 in the case of Candida sp. lipase. While in the case of immobilized lipozyme RMIM, The emulsion substrates were formulated by using olive oil, triton X-100 (1% v/v in pH 8) and sodium phosphate buffer of pH 8 in ratio of 2:1:1. Absorbance was measured at 655 nm. The stability of this assay (in terms of colored heptane phase absorbance readings) retained more than 92.5% after 24 h at 4°C compared to the absorbance readings measured at zero time. In comparison with other lipase assay methods, beside the developed sensitivity, the reproducibility and the lower limit of detection (LOD) of the proposed method, it permits analyzing of 96 samples at one time in a 96-well microplate. Furthermore, it consumes small quantities of chemicals and unit operations.

  4. Degradation-by-design: Surface modification with functional substrates that enhance the enzymatic degradation of carbon nanotubes.

    PubMed

    Sureshbabu, Adukamparai Rajukrishnan; Kurapati, Rajendra; Russier, Julie; Ménard-Moyon, Cécilia; Bartolini, Isacco; Meneghetti, Moreno; Kostarelos, Kostas; Bianco, Alberto

    2015-12-01

    Biodegradation of carbon-based nanomaterials has been pursued intensively in the last few years, as one of the most crucial issues for the design of safe, clinically relevant conjugates for biomedical applications. In this paper it is demonstrated that specific functional molecules can enhance the catalytic activity of horseradish peroxidase (HRP) and xanthine oxidase (XO) for the degradation of carbon nanotubes. Two different azido coumarins and one cathecol derivative are linked to multi-walled carbon nanotubes (MWCNTs). These molecules are good reducing substrates and strong redox mediators to enhance the catalytic activity of HRP. XO, known to metabolize various molecules mainly in the mammalian liver, including human, was instead used to test the biodegradability of MWCNTs modified with an azido purine. The products of the biodegradation process are characterized by transmission electron microscopy and Raman spectroscopy. The results indicate that coumarin and catechol moieties have enhanced the biodegradation of MWCNTs compared to oxidized nanotubes, likely due to the capacity of these substrates to better interact with and activate HRP. Although azido purine-MWCNTs are degraded less effectively by XO than oxidized nanotubes, the data uncover the importance of XO in the biodegradation of carbon-nanomaterials leading to their better surface engineering for biomedical applications.

  5. Flexible CuS nanotubes-ITO film Schottky junction solar cells with enhanced light harvesting by using an Ag mirror.

    PubMed

    Wu, Chunyan; Zhang, Zihan; Wu, Yiliang; Lv, Peng; Nie, Biao; Luo, Linbao; Wang, Li; Hu, Jigang; Jie, Jiansheng

    2013-02-01

    Here we report the fabrication of a novel photovoltaic device based on CuS nanotubes (CuSNTs) and indium tin oxide (ITO) Schottky junctions. Large-quantity synthesis of CuSNTs was accomplished via a solution-based sacrificial template method under moderate conditions, while ITO Schottky contacts were fabricated via micro-fabrication and pulsed laser deposition (PLD). Upon light illumination, CuSNTs-ITO Schottky junctions exhibited pronounced photovoltaic behavior, giving rise to a power conversion efficiency of 1.17% on a conventional SiO(2)/Si substrate. Furthermore, by utilizing PET as the substrate, transparent and flexible CuSNTs-ITO solar cells were constructed and showed performance close to their device counterparts on a rigid substrate. Notably, it was found that the flexible devices were robust against tensile strain and could stand a bending angle up to ∼95°. To enhance the light absorption of the devices, an Ag mirror layer was deposited on the rear side of the PET substrate so as to allow multiple reflection and absorption of the incident light. As a result, the flexible devices showed a substantial performance improvement, yielding an efficiency of ∼2%. Our results demonstrate that low-cost and environmentally friendly CuSNTs-ITO solar cells are promising candidates for new-generation photovoltaic devices.

  6. Fabrication of three-dimensional hybrid nanostructure-embedded ITO and its application as a transparent electrode for high-efficiency solution processable organic photovoltaic devices.

    PubMed

    Kim, Jeong Won; Jeon, Hwan-Jin; Lee, Chang-Lyoul; Ahn, Chi Won

    2017-03-02

    Well-aligned, high-resolution (10 nm), three-dimensional (3D) hybrid nanostructures consisting of patterned cylinders and Au islands were fabricated on ITO substrates using an ion bombardment process and a tilted deposition process. The fabricated 3D hybrid nanostructure-embedded ITO maintained its excellent electrical and optical properties after applying a surface-structuring process. The solution processable organic photovoltaic device (SP-OPV) employing a 3D hybrid nanostructure-embedded ITO as the anode displayed a 10% enhancement in the photovoltaic performance compared to the photovoltaic device prepared using a flat ITO electrode, due to the improved charge collection (extraction and transport) efficiency as well as light absorbance by the photo-active layer.

  7. Microstructure, ferromagnetic and photoluminescence properties of ITO and Cr doped ITO nanoparticles using solid state reaction

    NASA Astrophysics Data System (ADS)

    Babu, S. Harinath; Kaleemulla, S.; Rao, N. Madhusudhana; Rao, G. Venugopal; Krishnamoorthi, C.

    2016-11-01

    Indium-tin-oxide (ITO) (In0.95Sn0.05)2O3 and Cr doped indium-tin-oxide (In0.90Sn0.05Cr0.05)2O3 nanoparticles were prepared using simple low cost solid state reaction method and characterized by different techniques to study their structural, optical and magnetic properties. Microstructures, surface morphology, crystallite size of the nanoparticles were studied using X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM). From these methods it was found that the particles were about 45 nm. Chemical composition and valence states of the nanoparticles were studied using energy dispersive analysis of X-rays (EDAX) and X-ray photoelectron spectroscopy (XPS). From these techniques it was observed that the elements of indium, tin, chromium and oxygen were present in the system in appropriate ratios and they were in +3, +4, +3 and -2 oxidation states. Raman studies confirmed that the nanoparticle were free from unintentional impurities. Two broad emission peaks were observed at 330 nm and 460 nm when excited wavelength of 300 nm. Magnetic studies were carried out at 300 K and 100 K using vibrating sample magnetometer (VSM) and found that the ITO nanoparticles were ferromagnetic at 100 K and 300 K. Where-as the room temperature ferromagnetism completely disappeared in Cr doped ITO nanoparticles at 100 K and 300 K.

  8. Isothiourea-Mediated Organocatalytic Michael Addition-Lactonization on a Surface: Modification of SAMs on Silicon Oxide Substrates.

    PubMed

    Chisholm, Ross; Parkin, John D; Smith, Andrew D; Hähner, Georg

    2016-04-05

    Tailoring the functionality of self-assembled monolayers (SAMs) can be achieved either by depositing prefunctionalized molecules with the appropriate terminal groups or by chemical modification of an existing SAM in situ. The latter approach is particularly advantageous to allow for diversity of surface functionalization from a single SAM and if the incorporation of bulky groups is desired. In the present study an organocatalytic isothiourea-mediated Michael addition-lactonization process analogous to a previously reported study in solution is presented. An achiral isothiourea, 3,4-dihydro-2H-pyrimido[2,1-b]benzothiazole (DHPB), promotes the intermolecular Michael addition-lactonization of a trifluoromethylenone terminated SAM and a variety of arylacetic acids affording C(6)-trifluoromethyldihydropyranones tethered to the surface. X-ray photoelectron spectroscopy, atomic force microscopy, contact angle, and ellipsometry analysis were conducted to confirm the presence of the substituted dihydropyranone. A model study of this approach was also performed in solution to probe the reaction diastereoselectivity as it cannot be measured directly on the surface.

  9. Fabrication and characterization of a CuO/ITO heterojunction with a graphene transparent electrode

    NASA Astrophysics Data System (ADS)

    Mageshwari, K.; Han, Sanghoo; Park, Jinsub

    2016-05-01

    In this paper, we investigate the electrical properties of a CuO-ITO heterojunction diode with the use of a graphene transparent electrode by current-voltage (I-V) characteristics. CuO thin films were deposited onto an ITO substrate by a simple sol-gel spin coating method and annealed at 500 °C. The x-ray diffraction pattern of the CuO thin films revealed the polycrystalline nature of CuO and exhibited a monoclinic crystal structure. FESEM images showed a uniform and densely packed particulate morphology. The optical band gap of CuO thin films estimated using UV-vis absorption spectra was found to be 2.50 eV. The I-V characteristics of the fabricated CuO-ITO heterojunction showed a well-defined rectifying behavior with improved electrical properties after the insertion of graphene. The electronic parameters of the heterostructure such as barrier height, ideality factor and series resistance were determined from the I-V measurements, and the possible current transport mechanism was discussed.

  10. Highly flexible, hybrid-structured indium tin oxides for transparent electrodes on polymer substrates

    SciTech Connect

    Triambulo, Ross E.; Kim, Jung-Hoon; Park, Jin-Woo; Na, Min-Young; Chang, Hye-Jung

    2013-06-17

    We developed highly flexible, hybrid-structured crystalline indium tin oxide (ITO) for use as transparent electrodes on polymer substrates by embedding Ag nanoparticles (AgNPs) into the substrate. The hybrid ITO consists of domains in one orientation grown on the AgNPs and a matrix of the other orientation. The domains are stronger than the matrix and function as barriers to crack propagation. As a result, both the critical bending radius (r{sub c}) (under which the resistivity change ({Delta}{rho}) is less than a given value) and the change in {Delta}{rho} with decreasing r significantly decreased in the hybrid ITO compared with homogenous ITO.

  11. Gravure printing of transparent conducting ITO coatings for display applications

    NASA Astrophysics Data System (ADS)

    Puetz, Joerg; Heusing, Sabine; de Haro Moro, Marcos; Ahlstedt, C. Mikael; Aegerter, Michel A.

    2005-09-01

    Transparent conducting coatings and patterns of ITO (indium tin oxide) were deposited by a direct gravure printing on PET foils using nanoparticle-based UV-curable inks. Solid areas with thicknesses ranging between 300 and >1000 nm were obtained by varying the ink composition (e.g. ITO content, solvents) and fundamental parameters of the printing plate such as the line density. The best ITO coating patterns showed a sheet resistance of 3 to 10 kΩ□ and a transmission of up to 88 % with a haze of less than 1 %. One of the most crucial steps during film formation is the drying of the wet film as it changes the rheology and polarity of the ink and in consequence decisively influences the film formation. Typical fields of application of the gravure-printed ITO patterned electrodes include smart windows, flexible displays and printed electronics.

  12. Ito equations out of domino cellular automaton with efficiency parameters

    NASA Astrophysics Data System (ADS)

    Czechowski, Zbigniew; Białecki, Mariusz

    2012-06-01

    Ito equations are derived for simple stochastic cellular automaton with parameters describing efficiencies for avalanche triggering and cell occupation. Analytical results are compared with the numerical one obtained from the histogram method. Good agreement for various parameters supports the wide applicability of the Ito equation as a macroscopic model of some cellular automata and complex natural phenomena which manifest random energy release. Also, the paper is an example of effectiveness of histogram procedure as an adequate method of nonlinear modeling of time series.

  13. Multifractal analysis of time series generated by discrete Ito equations

    SciTech Connect

    Telesca, Luciano; Czechowski, Zbigniew; Lovallo, Michele

    2015-06-15

    In this study, we show that discrete Ito equations with short-tail Gaussian marginal distribution function generate multifractal time series. The multifractality is due to the nonlinear correlations, which are hidden in Markov processes and are generated by the interrelation between the drift and the multiplicative stochastic forces in the Ito equation. A link between the range of the generalized Hurst exponents and the mean of the squares of all averaged net forces is suggested.

  14. Direct laser patterning of transparent ITO-Ag-ITO multilayer anodes for organic solar cells

    NASA Astrophysics Data System (ADS)

    Kim, Hyo-Joong; Seo, Ki-Won; Kim, Yong Hyeon; Choi, Jiyeon; Kim, Han-Ki

    2015-02-01

    Direct laser patterning of transparent ITO-Ag-ITO (IAI) multilayer anodes is investigated using a femtosecond fiber laser for application in organic solar cells (OSC) fabrication. By adjusting laser fluence and scan speed, we successfully patterned the IAI multilayer anode without changing the electrical or optical properties. At an optimized laser fluence of 0.6 J/cm2 and a scan speed of 200 mm/s, the patterned IAI multilayer was electrically isolated with a clean edge. The metallic Ag interlayer of the IAI multilayer plays an important role in direct laser patterning because it absorbed the laser and increases the maximum temperature in the IAI multilayer. In addition, the Ag layer could effectively decrease the temperature of the IAI multilayer after irradiation of laser. The OSC fabricated on the laser patterned IAI multilayer showed power conversion efficiencies of 3.12% (Ag 8 nm) and 2.85% (Ag 12 nm). Successful operation of the OSC indicates that direct laser patterning of IAI multilayer anodes is a promising, simple patterning technology for fabrication of IAI-based OSCs.

  15. Metal-free molecular junctions on ITO via amino-silane binding-towards optoelectronic molecular junctions.

    PubMed

    Sergani, S; Furmansky, Y; Visoly-Fisher, I

    2013-11-15

    Light control over currents in molecular junctions is desirable as a non-contact input with high spectral and spatial resolution provided by the photonic input and the molecular electronics element, respectively. Expanding the study of molecular junctions to non-metallic transparent substrates, such as indium tin oxide (ITO), is vital for the observation of molecular optoelectronic effects. Non-metallic electrodes are expected to decrease the probability of quenching of molecular photo-excited states, light-induced plasmonic effects, or significant electrode expansion under visible light. We have developed micron-sized, metal free, optically addressable ITO molecular junctions with a conductive polymer serving as the counter-electrode. The electrical transport was shown to be dominated by the nature of the self-assembled monolayer (SAM). The use of amino-silane (APTMS) as the chemical binding scheme to ITO was found to be significant in determining the transport properties of the junctions. APTMS allows high junction yields and the formation of dense molecular layers preventing electrical short. However, polar amino-silane binding to the ITO significantly decreased the conductance compared to thiol-bound SAMs, and caused tilted geometry and disorder in the molecular layer. As the effect of the molecular structure on transport properties is clearly observed in our junctions, such metal-free junctions are suitable for characterizing the optoelectronic properties of molecular junctions.

  16. Metal-free molecular junctions on ITO via amino-silane binding—towards optoelectronic molecular junctions

    NASA Astrophysics Data System (ADS)

    Sergani, S.; Furmansky, Y.; Visoly-Fisher, I.

    2013-11-01

    Light control over currents in molecular junctions is desirable as a non-contact input with high spectral and spatial resolution provided by the photonic input and the molecular electronics element, respectively. Expanding the study of molecular junctions to non-metallic transparent substrates, such as indium tin oxide (ITO), is vital for the observation of molecular optoelectronic effects. Non-metallic electrodes are expected to decrease the probability of quenching of molecular photo-excited states, light-induced plasmonic effects, or significant electrode expansion under visible light. We have developed micron-sized, metal free, optically addressable ITO molecular junctions with a conductive polymer serving as the counter-electrode. The electrical transport was shown to be dominated by the nature of the self-assembled monolayer (SAM). The use of amino-silane (APTMS) as the chemical binding scheme to ITO was found to be significant in determining the transport properties of the junctions. APTMS allows high junction yields and the formation of dense molecular layers preventing electrical short. However, polar amino-silane binding to the ITO significantly decreased the conductance compared to thiol-bound SAMs, and caused tilted geometry and disorder in the molecular layer. As the effect of the molecular structure on transport properties is clearly observed in our junctions, such metal-free junctions are suitable for characterizing the optoelectronic properties of molecular junctions.

  17. Ammonia plasma modification towards a rapid and low temperature approach for tuning electrical conductivity of ZnO nanowires on flexible substrates.

    PubMed

    Ong, Wei Li; Zhang, Chun; Ho, Ghim Wei

    2011-10-05

    Though the fabrication of ZnO nanostructures is economical and low temperature, the lack of a facile, reliable and low temperature methodology to tune its electrical conductivity has prevented it from competing with other semiconductors. Here, we carried out surface modification of ZnO nanowires using ammonia plasma with no heat treatment, and studied their electrical properties over an extended time frame of more than a year. The fabrication of flexible devices was demonstrated via various methods of transferring and aligning as-synthesized ZnO nanowires onto plastic substrates. Hall measurements of the plasma modified ZnO nanowires revealed p-type conductivity. The N1s peak was present in the X-ray photoelectron spectrum of the surface modified ZnO, showing the presence of ammonia complexes. Low temperature photoluminescence showed evidence of acceptor-bound exciton emission. The resulting electrical devices, a chemical sensor and p-n homojunction, show the tunable electrical response of the surface modified ZnO nanowires.

  18. Catalyst-free growth of ZnO nanowires on ITO seed layer/glass by thermal evaporation method: Effects of ITO seed layer laser annealing temperature

    NASA Astrophysics Data System (ADS)

    Alsultany, Forat H.; Hassan, Z.; Ahmed, Naser M.

    2016-04-01

    Novel catalyst-free growth of ZnO nanowires (ZnO-NWs) on ITO seeds/glass substrate by thermal evaporation method, and effects of continuous wave CO2 laser thermal annealed seed layer on the morphology and properties of ZnO-NWs growth were investigated. The effects of sputtered ITO seed layer laser annealing temperature on the morphological, structural, and optical properties of ZnO-NWs was systematically investigated at temperatures 250, 350, and 450 °C, respectively. The surface morphology and structure of the seeds and the products of ZnO-NWs were characterized in detail by using field emission scanning electron microscopy, atomic force microscopy, and X-ray diffraction. Optical properties were further examined through photoluminescence, and UV-Vis spectrophotometer. A growth mechanism was proposed on the basis of obtained results. The results showed that the nanowires were strongly dependent on the seed layer annealing temperatures, which played an important role in nucleation and dissimilar growth of the nanowires with varying sizes and geometric shapes.

  19. On-chip nanostructuring and impedance trimming of transparent and flexible ITO electrodes by laser induced coherent sub-20 nm cuts

    NASA Astrophysics Data System (ADS)

    Afshar, Maziar; Leber, Moritz; Poppendieck, Wigand; König, Karsten; Seidel, Helmut; Feili, Dara

    2016-01-01

    In this work, the effect of laser-induced nanostructuring of transparent indium tin oxide (ITO) electrodes on flexible glass is investigated. Multi-electrode arrays (MEA) for electrical and optical characterization of biological cells were fabricated using standard MEMS technologies. Optimal sputter parameters concerning oxygen flow, sputter power and ambient pressure for ITO layers with both good optical and electrical properties were determined. Afterwards, coherent sub-20 nm wide and 150 nm deep nanocuts of many micrometers in length were generated within the ITO electrodes by a sub-15 femtosecond (fs) pulsed laser. The influence of laser processing on the electrical and optical properties of electrodes was investigated. The electrochemical impedance of the manufactured electrodes was measured before and after laser modification using electrochemical impedance spectroscopy. A small reduction in electrode impedance was observed. These nanostructured electrodes show also polarizing effects by the visible spectrum.

  20. Fabrication of printed ITO sensor for the ammonia hydroxide detection

    NASA Astrophysics Data System (ADS)

    Lee, Seok-hwan; Koo, Jieun; Jung, Soohoon; Lee, Moonjin; Jung, Jung-Yeul; Chang, Jiho

    2015-07-01

    Monitoring the hazardous and noxious substances (HNS) is a very important issue for mitigating the influence of catastrophic accidents in ocean and coastal areas. However, research on the HNS sensor is just in the beginning stage. In this study, we proposed a new HNS sensor using a printed ITO layer. We carried out a series of experiments of detecting the NH4OH and seawater solution to investigate the feasibility as a HNS sensor. The resistance of ITO layer dropped abruptly when it soaked into the solutions. The resistance change (δR) was linearly correlated with the NH4OH concentration of the solution, also it can be classified into two states; one is the transition stage, the other is the stabilized stage. The former is considered to be caused by the large capacitance of the electrical double layer (EDL) on the ITO surface. Also, the ITO layer showed considerable chemical stability within our experimental condition. In this paper, we have investigated the feasibility of printed ITO layer as a sensitive and cheap HNS sensor.

  1. Ubiquitin modifications

    PubMed Central

    Swatek, Kirby N; Komander, David

    2016-01-01

    Protein ubiquitination is a dynamic multifaceted post-translational modification involved in nearly all aspects of eukaryotic biology. Once attached to a substrate, the 76-amino acid protein ubiquitin is subjected to further modifications, creating a multitude of distinct signals with distinct cellular outcomes, referred to as the 'ubiquitin code'. Ubiquitin can be ubiquitinated on seven lysine (Lys) residues or on the N-terminus, leading to polyubiquitin chains that can encompass complex topologies. Alternatively or in addition, ubiquitin Lys residues can be modified by ubiquitin-like molecules (such as SUMO or NEDD8). Finally, ubiquitin can also be acetylated on Lys, or phosphorylated on Ser, Thr or Tyr residues, and each modification has the potential to dramatically alter the signaling outcome. While the number of distinctly modified ubiquitin species in cells is mind-boggling, much progress has been made to characterize the roles of distinct ubiquitin modifications, and many enzymes and receptors have been identified that create, recognize or remove these ubiquitin modifications. We here provide an overview of the various ubiquitin modifications present in cells, and highlight recent progress on ubiquitin chain biology. We then discuss the recent findings in the field of ubiquitin acetylation and phosphorylation, with a focus on Ser65-phosphorylation and its role in mitophagy and Parkin activation. PMID:27012465

  2. Highly flexible InSnO electrodes on thin colourless polyimide substrate for high-performance flexible CH3NH3PbI3 perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Park, Jeong-Il; Heo, Jin Hyuck; Park, Sung-Hyun; Hong, Ki Il; Jeong, Hak Gee; Im, Sang Hyuk; Kim, Han-Ki

    2017-02-01

    We fabricated high-performance flexible CH3NH3PbI3 (MAPbI3) perovskite solar cells with a power conversion efficiency of 15.5% on roll-to-roll sputtered ITO films on 60 μm-thick colourless polyimide (CPI) substrate. Due to the thermal stability of the CPI substrate, an ITO/CPI sample subjected to rapid thermal annealing at 300 °C showed a low sheet resistance of 57.8 Ω/square and high transmittance of 83.6%, which are better values than those of an ITO/PET sample. Outer and inner bending tests demonstrated that the mechanical flexibility of the ITO/CPI was superior to that of the conventional ITO/PET sample owing to the thinness of the CPI substrate. In addition, due to its good mechanical flexibility, the ITO/CPI showed no change in resistance after 10,000 cycle outer and inner dynamic fatigue tests. Flexible perovskite solar cells with the structure of Au/PTAA/MAPbI3/ZnO/ITO/CPI showed a high power conversion efficiency of 15.5%. The successful operation of these flexible perovskite solar cells on ITO/CPI substrate indicated that the ITO film on thermally stable CPI substrate is a promising of flexible substrate for high-temperature processing, a finding likely to advance the commercialization of cost-efficient flexible perovskite solar cells.

  3. Fabrication of ITO/Ag3SbS3/CdX (X = S, Se) thin film heterojunctions for photo-sensing applications

    NASA Astrophysics Data System (ADS)

    Daniel, T.; Henry, J.; Mohanraj, K.; Sivakumar, G.

    2016-11-01

    Thin film heterojunctions of Ag3SbS3/CdX (X = S, Se) are deposited on a glass substrate coated with SnO2:In (ITO). The films were characterized by x-ray diffraction (XRD), atomic force microscopy (AFM), UV-visible spectroscopy, photoluminescence spectroscopy, field emission scanning electron microscopy and I-V analysis. XRD reveals the monoclinic structure of Ag3SbS3 and a fcc structure for both CdS and CdSe thin films. The AFM images clearly show the distinct morphological features (nanopyramids, wedge-shaped and rectangular nanorod-like grains). From the I-V studies, under illumination, an ITO/Ag3SbS3/CdS heterojunction produces a higher photocurrent (12.4 mA) than that an ITO/Ag3SbS3/CdSe heterojunction (1.34 mA).

  4. ITO-free large-area organic light-emitting diodes with an integrated metal grid.

    PubMed

    Choi, Seungkeun; Kim, Sung-Jin; Fuentes-Hernandez, Canek; Kippelen, Bernard

    2011-07-04

    We report on ITO-free large-area organic light-emitting diodes (OLEDs) fabricated on glass substrates comprising α-NPD as a hole transport layer (HTL) and coevaporated CBP:Ir(ppy)(3) as the emission layer. Indium-tin-oxide (ITO) was replaced with a conductive polymer electrode and an electroplated thick metal grid was used to improve the homogeneity of the potential distribution over the transparent polymer electrode. An electrical model of a metal grid integrated OLED shows the benefits of the use of metal grids in terms of improving the uniformity of the light emitted as the area of the OLED increases as well as the conductivity of the transparent electrode decreases. By integrating metal grids with polymer electrodes, the luminance increases more than 24% at 6 V and 45% at 7 V compared to the polymer electrode devices without a metal grid. This implies that a lower voltage can be applied to achieve the same luminance, hence lowering the power consumption. Furthermore, metal grid integrated OLEDs exhibited less variation in light emission compared to devices without a metal grid.

  5. 7 CFR 254.3 - Administration by an ITO.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.3 Administration by an ITO. (a) Applicability of part 253....

  6. 7 CFR 254.4 - Application by an ITO.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.4 Application by an ITO. (a) Application to FNS Regional Office....

  7. 7 CFR 254.3 - Administration by an ITO.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.3 Administration by an ITO. (a) Applicability of part 253....

  8. 7 CFR 254.3 - Administration by an ITO.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.3 Administration by an ITO. (a) Applicability of part 253....

  9. 7 CFR 254.4 - Application by an ITO.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.4 Application by an ITO. (a) Application to FNS Regional Office....

  10. 7 CFR 254.3 - Administration by an ITO.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.3 Administration by an ITO. (a) Applicability of part 253....

  11. 7 CFR 254.3 - Administration by an ITO.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Agriculture Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.3 Administration by an ITO. (a) Applicability of part 253....

  12. 7 CFR 254.4 - Application by an ITO.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.4 Application by an ITO. (a) Application to FNS Regional Office....

  13. 7 CFR 254.4 - Application by an ITO.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.4 Application by an ITO. (a) Application to FNS Regional Office....

  14. 7 CFR 254.4 - Application by an ITO.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Regulations of the Department of Agriculture (Continued) FOOD AND NUTRITION SERVICE, DEPARTMENT OF AGRICULTURE GENERAL REGULATIONS AND POLICIES-FOOD DISTRIBUTION ADMINISTRATION OF THE FOOD DISTRIBUTION PROGRAM FOR INDIAN HOUSEHOLDS IN OKLAHOMA § 254.4 Application by an ITO. (a) Application to FNS Regional Office....

  15. NonMarkov Ito Processes with 1- state memory

    NASA Astrophysics Data System (ADS)

    McCauley, Joseph L.

    2010-08-01

    A Markov process, by definition, cannot depend on any previous state other than the last observed state. An Ito process implies the Fokker-Planck and Kolmogorov backward time partial differential eqns. for transition densities, which in turn imply the Chapman-Kolmogorov eqn., but without requiring the Markov condition. We present a class of Ito process superficially resembling Markov processes, but with 1-state memory. In finance, such processes would obey the efficient market hypothesis up through the level of pair correlations. These stochastic processes have been mislabeled in recent literature as 'nonlinear Markov processes'. Inspired by Doob and Feller, who pointed out that the ChapmanKolmogorov eqn. is not restricted to Markov processes, we exhibit a Gaussian Ito transition density with 1-state memory in the drift coefficient that satisfies both of Kolmogorov's partial differential eqns. and also the Chapman-Kolmogorov eqn. In addition, we show that three of the examples from McKean's seminal 1966 paper are also nonMarkov Ito processes. Last, we show that the transition density of the generalized Black-Scholes type partial differential eqn. describes a martingale, and satisfies the ChapmanKolmogorov eqn. This leads to the shortest-known proof that the Green function of the Black-Scholes eqn. with variable diffusion coefficient provides the so-called martingale measure of option pricing.

  16. Effect of organic solar cells using various power O2 plasma treatments on the indium tin oxide substrate.

    PubMed

    Ke, Jhong-Ciao; Wang, Yeong-Her; Chen, Kan-Lin; Huang, Chien-Jung

    2016-03-01

    The effect of organic solar cells (OSCs) by using different power O2 plasma treatments on indium tin oxide (ITO) substrate was studied. The power of O2 plasma treatment on ITO substrate was varied from 20W to 80W, and the power conversion efficiency of device was improved from 1.18% to 1.93% at 20W O2 plasma treatment. The function of O2 plasma treatment on ITO substrate was to remove the surface impurity and to improve the work function of ITO, which can reduce the energy offset between the ITO and SubPc layer and depress the leakage current of device, leading to the shunt resistance increased from 897 to 1100Ωcm(2). The surface roughness of ITO decreased from 3.81 to 3.33nm and the work function of ITO increased from 4.75 to 5.2eV after 20W O2 plasma treatment on ITO substrate. As a result, the open circuit voltage and the fill factor were improved from 0.46 to 0.70V and from 0.56 to 0.61, respectively. However, the series resistance of device was dramatically increased as the power of O2 plasma treatment exceeds 40W, leading to the efficiency reduction. The result is attributed to the variation of oxygen vacancies in ITO film after the 60, 80W O2 plasma treatment. As a consequence, the power of O2 plasma treatment on ITO substrate for the OSCs application should be controlled below 40W to avoid affecting the electricity of ITO film.

  17. Nd:YVO4 laser direct ablation of indium tin oxide films deposited on glass and polyethylene terephthalate substrates.

    PubMed

    Wang, Jian-Xun; Kwon, Sang Jik; Han, Jae-Hee; Cho, Eou Sik

    2013-09-01

    A Q-switched diode-pumped neodymium-doped yttrium vanadate (Nd:YVO4, lambda = 1064 nm) laser was applied to obtain the indium tin oxide (ITO) patterns on flexible polyethylene terephthalate (PET) substrate by a direct etching method. After the ITO films were deposited on a soda-lime glass and PET substrate, laser ablations were carried out on the ITO films for various conditions and the laser ablated results on the ITO films were investigated and analyzed considering the effects of substrates on the laser etching. The laser ablated widths on ITO deposited on glass were found to be much narrower than those on ITO deposited on PET substrate, especially, at a higher scanning speed of laser beam such as 1000 mm/s and 2000 mm/s. As the thermal conductivity of glass substrate is about 7.5 times higher than that of PET, more thermal energy would be spread and transferred to lateral direction in the ITO film in case of PET substrate.

  18. In situ electro-mechanical experiments and mechanics modeling of tensile cracking in indium tin oxide thin films on polyimide substrates

    NASA Astrophysics Data System (ADS)

    Peng, Cheng; Jia, Zheng; Bianculli, Dan; Li, Teng; Lou, Jun

    2011-05-01

    Indium tin oxide (ITO) thin films supported by polymer substrates have been widely used as transparent electrodes/interconnects in flexible electronics. Understanding the electro-mechanical behaviors of such material system is crucial for reliable operation of flexible devices under large deformation. In this paper, we performed in situ mechanical and electrical tests of ITO thin films with two different thicknesses (200 and 80 nm) deposited on polyimide substrates inside a scanning electron microscope. The crack initiation and propagation, crack density evolution and the corresponding electrical resistance variation were systematically investigated. It was found that cracks initiated at a higher tensile strain level and saturated with a higher density in thinner ITO films. Integrated with a coherently formulated mechanics model, the cohesive toughness and fracture strength of ITO thin films and the ITO/polyimide interfacial toughness were quantitatively determined. The experimentally observed thickness dependence of the saturated crack density in ITO thin films was also quantitatively verified by the model.

  19. Fine characterization of ITO layers by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Boher, Pierre; Defranoux, Christophe; Piel, Jean-Philippe; Stehle, Jean-Louis P.; Suzuki, Y.

    1996-08-01

    Indium tin oxide films (ITO) are characterized precisely by spectroscopic ellipsometry which determines not only the thickness of the layers but also the optical indices in a large spectral range. The quality of the ITO films is checked by the transparency of the layers in the visible range 0.4 to 0.6 micrometers . Indeed, target degradation is detected by the occurrence of an absorption band in this region. The electrical conductivity of the layer can also be deduced by the Drude model applied to the absorption in the infrared region. Moreover, spectroscopic ellipsometry can give all these information on all the surface of the panels, checking at the same time the homogeneity and the stability of the deposition process. Different experimental examples will be presented and discussed.

  20. Hypomelanosis of Ito and multiple naevoid hypertrichosis: rare cutaneous mosaicism.

    PubMed

    Khurana, Ananta; Singal, Archana; Pandhi, Deepika

    2014-05-01

    Hypomelanosis of Ito and naevoid hypertrichosis are both uncommon disorders and their coexistence in the same patient is rarely described. Most previously reported patients, in addition to cutaneous lesions, had multiple neurological, musculoskeletal and other organ system involvements. We present the case of a 3-year-old girl with these two naevoid disorders at sites completely exclusive of each other and without any severe associated defects.

  1. A three-dimensional metal grid mesh as a practical alternative to ITO.

    PubMed

    Jang, Sungwoo; Jung, Woo-Bin; Kim, Choelgyu; Won, Phillip; Lee, Sang-Gil; Cho, Kyeong Min; Jin, Ming Liang; An, Cheng Jin; Jeon, Hwan-Jin; Ko, Seung Hwan; Kim, Taek-Soo; Jung, Hee-Tae

    2016-08-07

    The development of a practical alternative to indium tin oxide (ITO) is one of the most important issues in flexible optoelectronics. In spite of recent progress in this field, existing approaches to prepare transparent electrodes do not satisfy all of their essential requirements. Here, we present a new substrate-embedded tall (∼350 nm) and thin (∼30 nm) three-dimensional (3D) metal grid mesh structure with a large area, which is prepared via secondary sputtering. This structure satisfies most of the essential requirements of transparent electrodes for practical applications in future opto-electronics: excellent optoelectronic performance (a sheet resistance of 9.8 Ω□(-1) with a transmittance of 85.2%), high stretchability (no significant change in resistance for applied strains <15%), a sub-micrometer mesh period, a flat surface (a root mean square roughness of approximately 5 nm), no haze (approximately 0.5%), and strong adhesion to polymer substrates (it survives attempted detachment with 3M Scotch tape). Such outstanding properties are attributed to the unique substrate-embedded 3D structure of the electrode, which can be obtained with a high aspect ratio and in high resolution over large areas with a simple process. As a demonstration of its suitability for practical applications, our transparent electrode was successfully tested in a flexible touch screen panel. We believe that our approach opens up new practical applications in wearable electronics.

  2. High substrate specificity factor ribulose bisphosphate carboxylase/oxygenase from eukaryotic marine algae and properties of recombinant cyanobacterial RubiSCO containing "algal" residue modifications.

    PubMed

    Read, B A; Tabita, F R

    1994-07-01

    Marine algae play an important role in removing carbon dioxide from the atmosphere. In this investigation, we have determined the substrate specificity factor of ribulose 1,5-bisphosphate carboxylase/oxygenase from several marine chromophytic and rhodophytic algae. The enzymes were purified to homogeneity and all possessed significantly higher substrate specificity factors than the enzymes from terrestrial plants, green algae, or bacteria. There are substantial differences in the sequence in a helix 6 of the large subunit of these enzymes, which is intriguing since residues of this region had been previously shown to influence the ability of ribulose bisphosphate carboxylase to discriminate between CO2 and O2, presumably by influencing the adjacent flexible loop 6 region. Sequence divergence at this and other key regions might contribute to the substantial differences in the substrate specificity factor of the chromophyte/rhodophyte enzyme. Initial studies on probing the basis for the high substrate specificity factor employed single amino acid substitutions in the recombinant cyanobacterial ribulose bisphosphate carboxylase. Residues in the vicinity of loop 6 were changed to reflect the corresponding residues in the chromophyte/rhodophyte large subunit. Some changes in the substrate specificity factor were noted, as were alterations in other important kinetic parameters. Since marine algae show little evidence of photorespiratory metabolism, the high substrate specificity of ribulose bisphosphate carboxylase is consistent with the physiology of these organisms. The results of this study provide further evidence that the properties of this enzyme may evolve or change according to the environment in which the host organism is found.

  3. MOCVD Growth of High-Quality and Density-Tunable GaAs Nanowires on ITO Catalyzed by Au Nanoparticles Deposited by Centrifugation.

    PubMed

    Wu, Dan; Tang, Xiaohong; Yoon, Ho Sup; Wang, Kai; Olivier, Aurelien; Li, Xianqiang

    2015-12-01

    High-quality and density-tunable GaAs nanowires (NWs) are directly grown on indium tin oxide (ITO) using Au nanoparticles (NPs) as catalysts by metal organic chemical vapor deposition (MOCVD). Au catalysts were deposited on ITO glass substrate using a centrifugal method. Compared with the droplet-only method, high-area density Au NPs were uniformly distributed on ITO. Tunable area density was realized through variation of the centrifugation time, and the highest area densities were obtained as high as 490 and 120 NP/μm(2) for 10- and 20-nm diameters of Au NPs, respectively. Based on the vapor-liquid-solid growth mechanism, the growth rates of GaAs NWs at 430 °C were 18.2 and 21.5 nm/s for the highest area density obtained of 10- and 20-nm Au NP-catalyzed NWs. The growth rate of the GaAs NWs was reduced with the increase of the NW density due to the competition of precursor materials. High crystal quality of the NWs was also obtained with no observable planar defects. 10-nm Au NP-induced NWs exhibit wurtzite structure whereas zinc-blende is observed for 20-nm NW samples. Controllable density and high crystal quality of the GaAs NWs on ITO demonstrate their potential application in hybrid a solar cell.

  4. The Study of Simulated Space Radiation Environment Effect on Conductive Properties of ITO Thermal Control Materials

    NASA Astrophysics Data System (ADS)

    Wei-Quan, Feng; Chun-Qing, Zhao; Zi-Cai, Shen; Yi-Gang, Ding; Fan, Zhang; Yu-Ming, Liu; Hui-Qi, Zheng; Xue, Zhao

    In order to prevent detrimental effects of ESD caused by differential surface charging of spacecraft under space environments, an ITO transparent conductive coating is often deposited on the thermal control materials outside spacecraft. Since the ITO coating is exposed in space environment, the environment effects on electrical property of ITO coatings concern designers of spacecraft deeply. This paper introduces ground tests to simulate space radiation environmental effects on conductive property of ITO coating. Samples are made of ITO/OSR, ITO/Kapton/Al and ITO/FEP/Ag thermal control coatings. Simulated space radiation environment conditions are NUV of 500ESH, 40 keV electron of 2 × 1016 е/cm2, 40 keV proton of 2.5 × 1015 p/cm2. Conductive property is surface resistivity measured in-situ in vacuum. Test results proved that the surface resistivity for all ITO coatings have a sudden decrease in the beginning of environment test. The reasons for it may be the oxygen vacancies caused by vacuum and decayed RIC caused by radiation. Degradation in conductive properties caused by irradiation were found. ITO/FEP/Ag exhibits more degradation than other two kinds. The conductive property of ITO/kapton/Al is stable for vacuum irradiation. The analysis of SEM and XPS found more crackers and less Sn and In concentration after irradiation which may be the reason for conductive property degradation.

  5. Pulsed laser deposition of ITO/AZO transparent contact layers for GaN LED applications.

    PubMed

    Ou, Sin Liang; Wuu, Dong Sing; Liu, Shu Ping; Fu, Yu Chuan; Huang, Shih Cheng; Horng, Ray Hua

    2011-08-15

    In this study, indium-tin oxide (ITO)/Al-doped zinc oxide (AZO) composite films were fabricated by pulsed laser deposition and used as transparent contact layers (TCLs) in GaN-based blue light emitting diodes (LEDs). The ITO/AZO TCLs were composed of the thin ITO (50 nm) films and AZO films with various thicknesses from 200 to 1000 nm. Conventional LED with ITO (200 nm) TCL prepared by E-beam evaporation was fabricated and characterized for comparison. From the transmittance spectra, the ITO/AZO films exhibited high transparency above 90% at wavelength of 465 nm. The sheet resistance of ITO/AZO TCL decreased as the AZO thickness increased, which could be attributed to the increase in a carrier concentration, leading to a decrease in the forward bias of LED. The LEDs with ITO/AZO composite TCLs showed better light extraction as compared to LED with ITO TCL in compliance with simulation. When an injection current of 20 mA was applied, the output power for LEDs fabricated with ITO/AZO TCLs had 45%, 63%, and 71% enhancement as compared with those fabricated using ITO (200 nm) TCL for the AZO thicknesses of 200, 460, and 1000 nm, respectively.

  6. Preparation of ZnO nanorods on conductive PET-ITO-Ag fibers

    NASA Astrophysics Data System (ADS)

    Li, Yiwen; Ji, Shuai; Chen, Yuanyu; Zhang, Hong; Gong, Yumei; Guo, Jing

    2016-12-01

    We studied the vertical ZnO nanorods grown on conductive conventional polyethylene terephthalate (PET) fibers which are prepared by electroless silver depositing on tin-doped indium oxide (ITO) coated PET fibers through an efficient and low-cost green approach. The PET fibers were firstly functionalized with a layer of ITO gel synthesized through a sol-gel process at rather low temperature, simply by immersing the fibers into ITO sol for several minutes followed by gelation at 120 °C. Once the ITO gel layer surface was activated by SnCl2, a continuous, uniform, and compact layer of silver was carried out on the surface of the PET-ITO fibers through electroless plating operation at room temperature. The as-prepared PET-ITO-Ag fibers had good electrical conductivity, with surface resistivity as low as 0.23 mΩ cm. The overall procedure is simple, efficient, nontoxic, and controllable. The conductive PET-ITO-Ag fiber was used successfully as a flexible basal material to plant vertical ZnO nanorods through controlling the seeding and growth processes. The morphology of the PET-ITO, PET-ITO-Ag, and PET-ITO-Ag-ZnO fibers were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Undergone the whole process, although the tensile strength of the fiber decreased slightly, they may still exert their applications in flexible electronic such as photovoltaic and piezoelectric devices.

  7. Micropatterning of mammalian cells on indium tin oxide substrates using ion implantation.

    PubMed

    Hwang, In-Tae; Ahn, Mi-Young; Jung, Chan-Hee; Choi, Jae-Hak; Shin, Kwanwoo

    2013-05-01

    In this study, a simple surface patterning method to create micropatterns of mammalian cells on indium tin oxide (ITO) substrates was developed using ion implantation. Thin polystyrene (PS) films spin-coated on an ITO glass was selectively implanted with accelerated proton ions through a pattern mask and then developed to generate PS micropatterns. Well-organized negative PS patterns were generated on the ITO glass. The results of the in vitro cell culture on the PS-patterned ITO glass with two types of cancer cell lines revealed the formation of well-defined cell patterns through a selective cell adhesion and proliferation only onto the ITO regions separated by PS regions. This facile method for cell patterning may be used to create a desired platform for cellular device applications, such as biosensors and cell microarrays.

  8. Effect of pyrolytic temperature on the properties of TiO2/ITO films for hydrogen sensing.

    PubMed

    Vijayalakshmi, K; Jereil, S David; Karthick, K

    2015-03-05

    Titanium dioxide (TiO2) thin films were prepared on ITO (222) coated glass substrates by spray pyrolysis technique. The influence of substrate temperature on the orientation, phase, vibrational bands and band gap energy of TiO2 films were discussed. The X-ray diffraction patterns of the films revealed preferentially oriented (101) TiO2 anatase phase at the substrate temperature of 300°C and 350°C. Fourier transform infrared spectra of the films showed the significant sharpening of absorption band at ∼645cm(-1) with increase in substrate temperature, which clearly indicates the formation of anatase phase dependent on substrate temperature. Fourier Raman Spectra of the films showed the significant presence of long range order anatase TiO2 phase. The optical measurements of the film prepared at different substrate temperatures revealed the direct band gap of 3.15-3.63eV and indirect band gap of 3.48-3.73eV, characteristic of TiO2 anatase phase. To understand the enhancement of sensing performances of TiO2 films with substrate temperature, the gas sensing mechanism of the films towards 400sccm of hydrogen at room temperature was studied and discussed.

  9. Experimental investigation of metallic thin film modification of nickel substrates for chemical vapor deposition growth of single layer graphene at low temperature

    NASA Astrophysics Data System (ADS)

    Aminalragia Giamini, Sigiava; Marquez-Velasco, Jose; Sakellis, Ilias; Tsipas, Polychronis; Kelaidis, Nikolaos; Tsoutsou, Dimitra; Boukos, Nikolaos; Kantarelou, Vasiliki; Xenogiannopoulou, Evangelia; Speliotis, Thanassis; Aretouli, Kleopatra; Kordas, George; Dimoulas, Athanasios

    2016-11-01

    Lowering the growth temperature of single layer graphene by chemical vapor deposition (CVD) is important for its real-life application and mass production. Doing this without compromising quality requires advances in catalytic substrates. It is shown in this work that deposition of Zn and Bi metals modify the surface of nickel suppressing the uncontrollable growth of multiple layers of graphene. As a result, single layer graphene is obtained by CVD at 600 °C with minimum amount of defects, showing substantial improvement over bare Ni. In contrast, Cu, and Mo suppress graphene growth. We also show that graphene grown with our method has a defect density that is strongly dependent on the roughness of the original nickel foil. Good quality or highly defective holey single layer graphene can be grown at will by selecting a smooth or rough foil substrate respectively.

  10. Modification of the wettability of a polymeric substrate by pH effect. Determination of the surface acid dissociation constant by contact angle measurements.

    PubMed

    Badre, Chantal; Mayaffre, Alain; Letellier, Pierre; Turmine, Mireille

    2006-09-26

    The wetting properties of a substrate can be changed by chemical reaction. Here, we studied simple materials with acid-base properties, by preparing poly(vinyl chloride) films containing lauric acid. These substrates constitute simple polymeric surfaces the wettability of which can be easily controlled by the acid-base equilibrium. The roughness of the material was then varied by adding Aerosil (hydrophobic fumed silica). We then studied the wettability of these materials toward aqueous buffer solutions between pH 2 and 12 from contact angle measurements. The variation of the contact angle of a droplet of buffer solution with the pH of the solution was described by a simple thermodynamic model requiring only two parameters. Thus, we could characterize the acid polymer by an effective surface acid dissociation constant the value of which was consistent with those obtained with a similar surface. We showed that the behavior of any substrate could be described even if the surface geometry was not well-known.

  11. Artificially MoO3 graded ITO anodes for acidic buffer layer free organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Lee, Hye-Min; Kim, Seok-Soon; Kim, Han-Ki

    2016-02-01

    We report characteristics of MoO3 graded ITO anodes prepared by a RF/DC graded sputtering for acidic poly(3,4-ethylene dioxylene thiophene):poly(styrene sulfonic acid) (PEDOT:PSS)-free organic solar cells (OSCs). Graded sputtering of the MoO3 buffer layer on top of the ITO layer produced MoO3 graded ITO anodes with a sheet resistance of 12.67 Ω/square, a resistivity of 2.54 × 10-4 Ω cm, and an optical transmittance of 86.78%, all of which were comparable to a conventional ITO anode. In addition, the MoO3 graded ITO electrode showed a greater work function of 4.92 eV than that (4.6 eV) of an ITO anode, which is beneficial for hole extraction from an organic active layer. Due to the high work function of MoO3 graded ITO electrodes, the acidic PEDOT:PSS-free OSCs fabricated on the MoO3 graded ITO electrode exhibited a power conversion efficiency 3.60% greater than that of a PEDOT:PSS-free OSC on the conventional ITO anode. The successful operation of PEDOT:PSS-free OSCs indicates simpler fabrication steps for cost-effective OSCs and elimination of interfacial reactions caused by the acidic PEDOT:PSS layer for reliable OSCs.

  12. The crystallinity and mechanical properties of indium tin oxide coatings on polymer substrates

    SciTech Connect

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo

    2011-02-15

    We present the relationship between the microstructure and mechanical strength of indium tin oxide (ITO) on flexible substrates. With varying thickness (h{sub f}), ITO is deposited on polyethylene terephthalate (PET) by dc magnetron sputtering. The microstructure of ITO is controlled by substrate surface conditions and sputtering parameters. The maximum substrate temperature during deposition is limited to 80 deg. C due to the low glass transition temperature (T{sub g}) of PET. The crystallinity and surface roughness (R{sub rms}) are analyzed by high resolution x-ray diffraction, high resolution transmission electron microscopy, and AFM. The crack resistance of ITO is evaluated by uniaxial tension test. The experimental results reveal that, at a fixed h{sub f}, the degree and quality of crystallinity of ITO are highly improved by increasing sputtering power and the substrate temperature. As the crystallinity is improved, the ratio of preferred growth orientations of (222) to (400) is increased and the degree of peak shifts to lower 2{theta} is decreased. They indicate that the crystallinity is improved as the lattice damage is reduced and film density is increased. The tension test results confirm that, up to a certain h{sub f}, the strength of ITO can be significantly enhanced by improving the microstructures.

  13. Structure, stability and electrochromic properties of polyaniline film covalently bonded to indium tin oxide substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Wenzhi; Ju, Wenxing; Wu, Xinming; Wang, Yan; Wang, Qiguan; Zhou, Hongwei; Wang, Sumin; Hu, Chenglong

    2016-03-01

    Indium tin oxide (ITO) substrate was modified with 4-aminobenzylphosphonic acid (ABPA), and then the polyaniline (PANI) film covalently bonded to ITO substrate was prepared by the chemical oxidation polymerization. X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and atomic force microscopy (AFM) measurements demonstrated that chemical binding was formed between PANI and ABPA-modified ITO surface, and the maximum thickness of PANI layer is about 30 nm. The adhesive strength of PANI film on ITO substrate was tested by sonication. It was found that the film formed on the modified ITO exhibited a much better stability than that on bare one. Cyclic voltammetry (CV) and UV-vis spectroscopy measurements indicated that the oxidative potentials of PANI film on ABPA-modified ITO substrate were decreased and the film exhibited high electrochemical activities. Moreover, the optical contrast increased from 0.58 for PANI film (without ultrasound) to 1.06 for PANI film (after ultrasound for 60 min), which had an over 83% enhancement. The coloration time was 20.8 s, while the bleaching time was 19.5 s. The increase of electrochromic switching time was due to the lower ion diffusion coefficient of the large cation of (C4H9)4N+ under the positive and negative potentials as comparison with the small Li+ ion.

  14. Investigation of ITO free transparent conducting polymer based electrode

    NASA Astrophysics Data System (ADS)

    Sharma, Vikas; Sapna, Sachdev, Kanupriya

    2016-05-01

    The last few decades have seen a significant improvement in organic semiconductor technology related to solar cell, light emitting diode and display panels. The material and structure of the transparent electrode is one of the major concerns for superior performance of devices such as OPV, OLED, touch screen and LCD display. Commonly used ITO is now restricted due to scarcity of indium, its poor mechanical properties and rigidity, and mismatch of energy levels with the active layer. Nowadays DMD (dielectric-metal-dielectric) structure is one of the prominent candidates as alternatives to ITO based electrode. We have used solution based spin coated polymer layer as the dielectric layer with silver thin film embedded in between to make a polymer-metal-polymer (PMP) structure for TCE applications. The PMP structure shows low resistivity (2.3 x 10-4Ω-cm), high carrier concentration (2.9 x 1021 cm-3) and moderate transparency. The multilayer PMP structure is characterized with XRD, AFM and Hall measurement to prove its suitability for opto-electronic device applications.

  15. Dealloying Ag-Al alloy to prepare nanoporous silver as a substrate for surface-enhanced Raman scattering: effects of structural evolution and surface modification.

    PubMed

    Qiu, Huajun; Zhang, Zhonghua; Huang, Xirong; Qu, Yinbo

    2011-08-01

    Sensitive detection of molecules by using the surface-enhanced Raman scattering (SERS) technique depends on the nanostructured metallic substrate and many efforts have been devoted to the preparation of SERS substrates with high sensitivity, stability, and reproducibility. Herein, we report on the fabrication of stable monolithic nanoporous silver (NPS) by chemical dealloying of Ag-Al precursor alloys with an emphasis on the effect of structural evolution on SERS signals. It was found that the dealloying conditions had great influence on the morphology (the ligament/pore size) and the crystallization status, which determined the SERS signal of rhodamine 6G on the NPS. NPS with small pores, low residual Al, and perfect crystallization gave high SERS signals. A high enhancement factor of 7.5 × 10(5) was observed on bare NPS obtained by dealloying Ag(30)Al(70) in 2.5 wt % HCl at room temperature followed by 15 min aging at around 85 °C. After coating Ag nanoparticles on the NPS surface, the enhancement factor increased to 1.6 × 10(8) owing to strong near-field coupling between the ligaments and nanoparticles.

  16. The effect of substrate temperature on the microstructural, electrical and optical properties of Sn-doped indium oxide thin films

    NASA Astrophysics Data System (ADS)

    Raoufi, Davood; Taherniya, Atefeh

    2015-06-01

    In this work, Sn doping In2O3 (ITO) thin films with a thickness of 200 nm were deposited on glass substrates by electron beam evaporation (EBE) method at different substrate temperatures. The crystal structure of these films was studied by X-ray diffraction technique. The sheet resistance was measured by a four-point probe. Van der Pauw method was used to measure carrier density and mobility of ITO films. The optical transmittance spectra were recorded in the wavelength region of 300-800 nm. Scanning electron microscope (SEM) has been used for the surface morphology analysis. The prepared ITO films exhibited body-centered cubic (BCC) structure with preferred orientation of growth along the (2 2 2) crystalline plane. The grain size of the films increases by rising the substrate temperature. Transparency of the films, over the visible light region, is increased with increasing the substrate temperature. It is found that the electrical properties of ITO films are significantly affected by substrate temperature. The electrical resistivity decreases with increasing substrate temperature, whereas the carrier density and mobility are enhanced with an increase in substrate temperature. The evaluated values of energy band gap Eg for ITO films were increase from 3.84 eV to 3.91 eV with increasing the substrate temperatures from 200 °C to 500 °C. The SEM micrographs of the films revealed a homogeneous growth without perceptible cracks with particles which are well covered on the substrate.

  17. One-step synthesis of carbon nanosheets converted from a polycyclic compound and their direct use as transparent electrodes of ITO-free organic solar cells.

    PubMed

    Son, Su-Young; Noh, Yong-Jin; Bok, Changsuk; Lee, Sungho; Kim, Byoung Gak; Na, Seok-In; Joh, Han-Ik

    2014-01-21

    Through a catalyst- and transfer-free process, we fabricated indium tin oxide (ITO)-free organic solar cells (OSCs) using a carbon nanosheet (CNS) with properties similar to graphene. The morphological and electrical properties of the CNS derived from a polymer of intrinsic microporosity-1 (PIM-1), which is mainly composed of several aromatic hydrocarbons and cycloalkanes, can be easily controlled by adjusting the polymer concentration. The CNSs, which are prepared by simple spin-coating and heat-treatment on a quartz substrate, are directly used as the electrodes of ITO-free OSCs, showing a high efficiency of approximately 1.922% under 100 mW cm(-2) illumination and air mass 1.5 G conditions. This catalyst- and transfer-free approach is highly desirable for electrodes in organic electronics.

  18. A three-dimensional metal grid mesh as a practical alternative to ITO

    NASA Astrophysics Data System (ADS)

    Jang, Sungwoo; Jung, Woo-Bin; Kim, Choelgyu; Won, Phillip; Lee, Sang-Gil; Cho, Kyeong Min; Jin, Ming Liang; An, Cheng Jin; Jeon, Hwan-Jin; Ko, Seung Hwan; Kim, Taek-Soo; Jung, Hee-Tae

    2016-07-01

    The development of a practical alternative to indium tin oxide (ITO) is one of the most important issues in flexible optoelectronics. In spite of recent progress in this field, existing approaches to prepare transparent electrodes do not satisfy all of their essential requirements. Here, we present a new substrate-embedded tall (~350 nm) and thin (~30 nm) three-dimensional (3D) metal grid mesh structure with a large area, which is prepared via secondary sputtering. This structure satisfies most of the essential requirements of transparent electrodes for practical applications in future opto-electronics: excellent optoelectronic performance (a sheet resistance of 9.8 Ω □-1 with a transmittance of 85.2%), high stretchability (no significant change in resistance for applied strains <15%), a sub-micrometer mesh period, a flat surface (a root mean square roughness of approximately 5 nm), no haze (approximately 0.5%), and strong adhesion to polymer substrates (it survives attempted detachment with 3M Scotch tape). Such outstanding properties are attributed to the unique substrate-embedded 3D structure of the electrode, which can be obtained with a high aspect ratio and in high resolution over large areas with a simple process. As a demonstration of its suitability for practical applications, our transparent electrode was successfully tested in a flexible touch screen panel. We believe that our approach opens up new practical applications in wearable electronics.The development of a practical alternative to indium tin oxide (ITO) is one of the most important issues in flexible optoelectronics. In spite of recent progress in this field, existing approaches to prepare transparent electrodes do not satisfy all of their essential requirements. Here, we present a new substrate-embedded tall (~350 nm) and thin (~30 nm) three-dimensional (3D) metal grid mesh structure with a large area, which is prepared via secondary sputtering. This structure satisfies most of the essential

  19. Fabrication and characterization of ITO/silicon SIS solar cells. Final report, October 1, 1978-April 30, 1980

    SciTech Connect

    DuBow, J. B.

    1980-06-01

    The objectives of this research were to optimize the performance of ITO/polycrystalline silicon solar cells, identify performance limitations, identify major stability problems which would inhibit terrestrial application of these devices, evaluate the impact of indium supply and price on terrestrial applications, and evaluate the economic viability of ITO sputter deposited solar cells. These goals were successfully achieved during the course of this multipronged effort. Both area scaling with efficiency maintenance were achieved by process modifications including surface preparation and in-situ passivation techniques. Indium tin oxide on Wacker polycrystalline silicon solar cells were fabricated which achieved 13.7% efficiency for 11 cm/sup 2/ devices. Typical open circuit voltages were 0.525 volts, short circuit currents, 34 mA/cm/sup 2/, and fill factors of 0.75. In the course of this project, three device measurement techniques which assisted in improving cell efficiency and which have broad applicability to all photovoltaic devices were introduced. These were automated admittance and surface state analysis, noise spectral density analysis, and automated I-V and C-V analysis. These measurements were combined with Auger/ESCA, EBIC and flying spot scanner, and other measurement techniques to identify grain boundaries, intragrain defects, edge leakage, and interface losses which were subsequently alleviated through process improvements. It is concluded from this work that prototype production of cells and modules based on this technology would be warranted in the near term.

  20. One-step synthesis of carbon nanosheets converted from a polycyclic compound and their direct use as transparent electrodes of ITO-free organic solar cells

    NASA Astrophysics Data System (ADS)

    Son, Su-Young; Noh, Yong-Jin; Bok, Changsuk; Lee, Sungho; Kim, Byoung Gak; Na, Seok-In; Joh, Han-Ik

    2013-12-01

    Through a catalyst- and transfer-free process, we fabricated indium tin oxide (ITO)-free organic solar cells (OSCs) using a carbon nanosheet (CNS) with properties similar to graphene. The morphological and electrical properties of the CNS derived from a polymer of intrinsic microporosity-1 (PIM-1), which is mainly composed of several aromatic hydrocarbons and cycloalkanes, can be easily controlled by adjusting the polymer concentration. The CNSs, which are prepared by simple spin-coating and heat-treatment on a quartz substrate, are directly used as the electrodes of ITO-free OSCs, showing a high efficiency of approximately 1.922% under 100 mW cm-2 illumination and air mass 1.5 G conditions. This catalyst- and transfer-free approach is highly desirable for electrodes in organic electronics.Through a catalyst- and transfer-free process, we fabricated indium tin oxide (ITO)-free organic solar cells (OSCs) using a carbon nanosheet (CNS) with properties similar to graphene. The morphological and electrical properties of the CNS derived from a polymer of intrinsic microporosity-1 (PIM-1), which is mainly composed of several aromatic hydrocarbons and cycloalkanes, can be easily controlled by adjusting the polymer concentration. The CNSs, which are prepared by simple spin-coating and heat-treatment on a quartz substrate, are directly used as the electrodes of ITO-free OSCs, showing a high efficiency of approximately 1.922% under 100 mW cm-2 illumination and air mass 1.5 G conditions. This catalyst- and transfer-free approach is highly desirable for electrodes in organic electronics. Electronic supplementary information (ESI) available: Detailed experimental methods; chemical structure and 1H NMR spectra; AFM images; TGA spectra; shunt and series resistances; Raman spectra and optical images; atomic contents of the CNSs. See DOI: 10.1039/c3nr04828d

  1. Fabrication, characterization and applications of PZT and ITO nanostructures

    NASA Astrophysics Data System (ADS)

    Xu, Shiyou

    Lead Zirconate Titanate (PbZr1--xTixO 3, PZT) is one of the most important piezoelectric materials, which has been used traditionally as sensors and actuators. One dimensional (1-D) PZT is expected to have great potentials as building blocks for micro and nano sensors and actuators, nano active fiber composites and integrated nanosystems. The objective of this research is to investigate the size effect on mechanical and piezoelectric properties through the fabrication and characterization of 1-D PZT nanostructures such as PZT nanofibers and nanotubes. The electrospinning process and template-assisted method were used to synthesize PZT nanofibers and nanotubes, respectively. Various novel experimental methods, such as atomic force microscopy (AFM) and nanomanipulator, were used to characterize the mechanical and piezoelectric properties of PZT nanostructures. The obtained results have shown that the piezoelectric and mechanical properties of PZT are size dependent. A single PZT nanofiber presented a lower young's modulus (42.99 GPa measured from AFM-base method and 46.6 GPa from vibration-based method, respectively) than that of PZT thin films and bulks. The PZT nanofibers with diameters smaller than 150 nm still demonstrated a strong electromechanical coupling effect. The piezoelectric constant (d 33) of PZT nanofibers increased from 574.1 pm/V to 860.5 pm/V when their diameters decreased from 112 nm to 50 nm. PZT nanotubes were found to have a d33 value of up to 595 pm/V. These values are significantly higher than that of PZT thin films and comparable to that of PZT bulks. The PZT nanofibers and nanotubes developed in this research not only provide new types of sensing and actuation mechanisms for various novel nanodevices, but also provide significantly improved performance compared with their thin film counterpart used in microelectromechanical systems (MEMS). 1-D ITO nanostructures (nanofibers and nanotubes) were synthesized and characterized for potential use

  2. Dual enzyme mimicry exhibited by ITO nanocubes and their application in spectrophotometric and electrochemical sensing.

    PubMed

    Aneesh, K; Vusa, Chiranjeevi Srinivasa Rao; Berchmans, Sheela

    2016-06-20

    The dual enzyme mimicry (peroxidase/catalase-like activities) exhibited by ITO nanocubes (ITO NCs) was investigated by spectrophotometric and electrochemical methods. The peroxidase mimic was successfully applied for the electrochemical detection of H2O2 and spectrophotometric biosensing of glucose. Further, the detection could be extended to the detection of glucose in real samples.

  3. Comparative study of ITO and FTO thin films grown by spray pyrolysis

    SciTech Connect

    Ait Aouaj, M.; Diaz, R.; Belayachi, A.; Rueda, F.; Abd-Lefdil, M.

    2009-07-01

    Tin doped indium oxide (ITO) and fluorine doped tin oxide (FTO) thin films have been prepared by one step spray pyrolysis. Both film types grown at 400 deg. C present a single phase, ITO has cubic structure and preferred orientation (4 0 0) while FTO exhibits a tetragonal structure. Scanning electron micrographs showed homogeneous surfaces with average grain size around 257 and 190 nm for ITO and FTO respectively. The optical properties have been studied in several ITO and FTO samples by transmittance and reflectance measurements. The transmittance in the visible zone is higher in ITO than in FTO layers with a comparable thickness, while the reflectance in the infrared zone is higher in FTO in comparison with ITO. The best electrical resistivity values, deduced from optical measurements, were 8 x 10{sup -4} and 6 x 10{sup -4} {Omega} cm for ITO (6% of Sn) and FTO (2.5% of F) respectively. The figure of merit reached a maximum value of 2.15 x 10{sup -3} {Omega}{sup -1} for ITO higher than 0.55 x 10{sup -3} {Omega}{sup -1} for FTO.

  4. (110)-oriented indium tin oxide films grown on m- and r-plane sapphire substrates

    NASA Astrophysics Data System (ADS)

    Chern, Ming-Yau; Lu, Tso-Wen; Xu, Wei-Lun

    2015-04-01

    Indium tin oxide (ITO) thin films have been deposited by pulsed laser deposition on m-plane (100) and r-plane (012) sapphire substrates. For both substrates, the films were grown with their [110] direction perpendicular to the substrate planes under the conditions of high growth temperature and high oxygen pressure. Their in-plane epitaxial relations with the substrates were identified to be ITO[001] ∥ Al2O3[020] and \\text{ITO}[1\\bar{1}0]\\parallel \\text{Al}2\\text{O}3[001] for the m-plane substrate. For the r-plane substrate, two types of lattice matching were observed: one being \\text{ITO}[001]\\parallel \\text{Al}2\\text{O}3[2,1, - 1/2] and \\text{ITO}[1\\bar{1}0]\\parallel \\text{Al}2\\text{O}3[4/3, - 4/3,2/3], the other being \\text{ITO}[001]\\parallel \\text{Al}2\\text{O}3[1, - 1,1/2] and \\text{ITO}[1\\bar{1}0]/\\text{Al}2\\text{O}3[8/3,4/3, - 2/3]. The electrical properties were measured by the Hall effect and van der Pauw methods at room temperature. All of the samples have low electrical resistivity on the order of 3.0 × 10-4 Ω cm, high carrier concentration of about 2.5 × 1020 cm-3, and mobility ranging from 70 to 90 cm2 V-1 s-1.

  5. Conditioning-specific reflex modification of the rabbit's nictitating membrane response and heart rate: behavioral rules, neural substrates, and potential applications to posttraumatic stress disorder.

    PubMed

    Burhans, Lauren B; Smith-Bell, Carrie; Schreurs, Bernard G

    2008-12-01

    Interest in classical conditioning is usually focused on anticipatory responses to a stimulus associated with a significant event, and it is assumed that responses to the event itself are reflexive, involuntary, and relatively invariant. However, there is compelling evidence that both the rabbit nictitating membrane response (NMR) and heart rate response (HR), well-known reflexive reactions to aversive events, can change quite dramatically as a function of learning when measured in the absence of the conditioned stimulus. In the case of NMR conditioning, a simple blink is transformed into a larger and more complex response. For HR conditioning, reflexive heart rate acceleration can actually change to heart rate deceleration. In both cases, the reflex comes to resemble the conditioned response and follows some of the same behavioral laws. This change in response to the aversive event itself or weaker forms of that event is called conditioning-specific reflex modification (CRM). CRM may force us to reevaluate the behavioral and neural consequences of classical conditioning and may have important consequences for the treatment of conditions such as posttraumatic stress disorder.

  6. Very High Output Thermoelectric Devices Based on ITO Nanocomposites

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave; Gregory, Otto J.

    2009-01-01

    A material having useful thermoelectric properties was synthesized by combining indium-tin-oxide (ITO) with a NiCoCrAlY alloy/alumina cermet. This material had a very large Seebeck coefficient with electromotive-force-versustemperature behavior that is considered to be excellent with respect to utility in thermocouples and other thermoelectric devices. When deposited in thin-film form, ceramic thermocouples offer advantages over precious-metal (based, variously, on platinum or rhodium) thermocouples that are typically used in gas turbines. Ceramic thermocouples exhibit high melting temperatures, chemical stability at high temperatures, and little or no electromigration. Oxide ceramics also resist oxidation better than metal thermocouples, cost substantially less than precious-metal thermocouples, and, unlike precious-metal thermocouples, do not exert catalytic effects.

  7. Chemical modification of hydroxynitrile lyase by selective reaction of an essential cysteine-SH group with alpha, beta-unsaturated propiophenones as pseudo-substrates.

    PubMed

    Jaenicke, L; Preun, J

    1984-01-16

    3-Oxo-3-phenylpropyne and 3-oxo-3-phenylpropene were synthesized as active-site-directed irreversible inhibitors of the bitter almond hydroxynitrile lyase (EC 4.1.2.10), an FAD-protein. The substrate and competitors (e.g. benzoate) decrease the rate of the inhibitor-mediated deactivation of the enzyme. By excess addition of either one of the two inhibitors, the deactivation process is shown to be pseudo-first order. The reaction with equimolar amounts of 3-oxo-3-phenylpropyne with the enzyme is accompanied by a shift in the ultraviolet spectrum of the inhibitor, allowing direct measurement of the enzyme-inactivation process. The spectral change has second-order kinetics. Incubation with 3-oxo-3-[p-3H]phenylpropyne or 3-oxo-3-[1-14C]phenylpropene shows a one-to-one stoichiometry for the inhibitory-enzyme reaction. Dissociation of the 3-oxo-3[p-3H]phenylpropyne-inactivated holoenzyme with acid ammonium sulfate yields a labeled apoenzyme; the inhibitor does not react with free or enzyme-bound FAD. After boranate reduction and exhaustive hydrolysis of the 3-oxo-3-[1-14C]phenylpropene-inactivated enzyme, a labeled cysteine derivative was isolated which was identified by chromatographic and mass spectroscopic comparison with synthetic references as L-2-amino-4-thia-DL-7-hydroxy-7-phenylhepatanoic acid, the reduced, linear addition product of the inhibitor to a cysteine-SH group.

  8. Modification of Titanium Substrates with Chimeric Peptides Comprising Antimicrobial and Titanium-Binding Motifs Connected by Linkers To Inhibit Biofilm Formation.

    PubMed

    Liu, Zihao; Ma, Shiqing; Duan, Shun; Xuliang, Deng; Sun, Yingchun; Zhang, Xi; Xu, Xinhua; Guan, Binbin; Wang, Chao; Hu, Meilin; Qi, Xingying; Zhang, Xu; Gao, Ping

    2016-03-02

    Bacterial adhesion and biofilm formation are the primary causes of implant-associated infection, which is difficult to eliminate and may induce failure in dental implants. Chimeric peptides with both binding and antimicrobial motifs may provide a promising alternative to inhibit biofilm formation on titanium surfaces. In this study, chimeric peptides were designed by connecting an antimicrobial motif (JH8194: KRLFRRWQWRMKKY) with a binding motif (minTBP-1: RKLPDA) directly or via flexible/rigid linkers to modify Ti surfaces. We evaluated the binding behavior of peptides using quartz crystal microbalance (QCM) and atomic force microscopy (AFM) techniques and investigated the effect of the modification of titanium surfaces with these peptides on the bioactivity of Streptococcus gordonii (S. gordonii) and Streptococcus sanguis (S. sanguis). Compared with the flexible linker (GGGGS), the rigid linker (PAPAP) significantly increased the adsorption of the chimeric peptide on titanium surfaces (p < 0.05). Concentration-dependent adsorption is consistent with a single Langmuir model, whereas time-dependent adsorption is in line with a two-domain Langmuir model. Additionally, the chimeric peptide with the rigid linker exhibited more effective antimicrobial ability than the peptide with the flexible linker. This finding was ascribed to the ability of the rigid linker to separate functional domains and reduce their interference to the maximum extent. Consequently, the performance of chimeric peptides with specific titanium-binding motifs and antimicrobial motifs against bacteria can be optimized by the proper selection of linkers. This rational design of chimeric peptides provides a promising alternative to inhibit the formation of biofilms on titanium surfaces with the potential to prevent peri-implantitis and peri-implant mucositis.

  9. Study on CdTe Quantum Dots Electrochemiluminescent Sensor Supported by Carbon Nano-tubes With ITO Basal Electrode

    NASA Astrophysics Data System (ADS)

    Caixia, Yu; Jilin, Yan; Yifeng, Tu

    2011-05-01

    The water soluble CdTe quantum dots (QDs) was synthesized with modified method. Its quantum yield was characterized for higher than 54%. Therefore a novel sensitive electrochemiluminescent (ECL) sensor was constructed based on the modification of composite of CdTe QDs, carbon nanotubes (CNTs) and chitosan (CHIT) on indium tin oxide (ITO) glass. After heat-treatment by infrared radiation, meanwhile with the co-reactant, triethylamine (TEA), the proposed sensor showed excellent anodic ECL efficiency and stability. This ECL sensor responded the dopamine (DA) in a wide linear range from 50 pM to 10 nM with a detection limit of 24 pM due to the quenching effect from DA. The DA contents in practical biological samples of cerebro-spinal fluid were detected with satisfactory recovery of average 95.7%.

  10. Understanding the molecular-level chemistry of water plasmas and the effects of surface modification and deposition on a selection of oxide substrates

    NASA Astrophysics Data System (ADS)

    Trevino, Kristina J.

    2011-12-01

    This dissertation first examines electrical discharges used to study wastewater samples for contaminant detection and abatement. Two different water samples contaminated with differing concentrations of either methanol (MeOH) or methyl tert-butyl ether (MTBE) were used to follow breakdown mechanisms. Emission from CO* was used to monitor the contaminant and for molecular breakdown confirmation through actinometric OES as it can only arise from the carbon-based contaminant in either system. Detection was achieved at concentrations as low as 0.01 ppm, and molecular decomposition was seen at a variety of plasma parameters. This dissertation also explores the vibrational (thetaV), rotational (thetaR) and translational (thetaT) temperatures for a range of diatomic species in different plasma systems. For the majority of the plasma species studied, thetaV are much higher than thetaR and thetaT. This suggests that more energy is partitioned into the vibrational degrees of freedom in our plasmas. The thetaR reported are significantly lower in all the plasma systems studied and this is a result of radical equilibration to the plasma gas temperature. thetaT values show two characteristics; (1) they are less than the thetaV and higher than the theta R and (2) show varying trends with plasma parameters. Radical energetics were examined through comparison of thetaR, thetaT, and thetaV, yielding significant insight on the partitioning of internal and kinetic energies in plasmas. Correlations between energy partitioning results and corresponding radical surface scattering coefficients obtained using our imaging of radicals interacting with surfaces (IRIS) technique are also presented. Another aspect of plasma process chemistry, namely surface modification via plasma treatment, was investigated through characterization of metal oxides (SiOxNy, nat-SiO2, and dep-SiO2) following their exposure to a range of plasma discharges. Here, emphasis was placed on the surface wettability

  11. Room temperature crystallization of indium tin oxide films on glass and polyethylene terephthalate substrates using rf plasma

    SciTech Connect

    Ohsaki, H.; Suzuki, M.; Shibayama, Y.; Kinbara, A.; Watanabe, T.

    2007-07-15

    The crystallization of amorphous indium tin oxide (ITO) films was achieved by rf (13.56 MHz) plasma treatment. Although the films were crystallized after 2 min, the sample temperature was lower than 90 deg. C without compulsory cooling even after 10 min of treatment and polyethylene terephthalate (PET) substrates had no damage. Plasma-crystallized sputtered ITO films have a bixbite structure and the resistivity reached to 1.6x10{sup -4} {omega}{center_dot}cm. ITO thin films have almost the same resistivity in both cases of PET and glass substrates used and plasma-treated PET ITO films have a bit higher resistivity than that of glass ITO films, while mass spectroscopy measurements indicated that ITO films deposited on PET substrates are expected to include no apparent gas species ejected from PET substrate. It was found that the plasma gas pressure is the key parameter for the effective crystallization and the appropriate gas pressure depends on the plasma gas species.

  12. Investigation of the Magnetic Properties of Ni-implanted ITO Thin Films

    NASA Astrophysics Data System (ADS)

    Ay, Figen; Aktas, Bekir; Khaibullin, Rustem; Nuzhdin, Vladimir; Rameev, Bulat

    Commercially available ITO thin films on fused silica substrates were implanted with 40 keV Ni+ ions to fluences of (0.5,1.0&1.5) ×1017 ions/cm2 at room temperature. XRR measurements show that the thickness of the implanted films (~ 28.5 nm) does not change noticeably with the fluence, while the surface roughness increases essentially. SEM and EDX studies revealed a highly non-uniform distribution of Ni atoms. Room temperature ferromagnetism was observed in the samples with fluences of (1.0&1.5) ×1017 ions/cm2. VSM hysteresis curves and FMR signal point to the formation of a ferromagnetic near-surface layer in the implanted films due to agglomeration of closely-spaced metal Ni nanoparticles. The filling factor of the Ni ferromagnetic phase in the granular magnetic layer was estimated from the FMR results. Super- and para- magnetic phases were observed in the temperature dependence of magnetization by VSM. Superparamagnetic phase is attributed to the Ni nanoparticles located in deeper regions near the film/substrate interface, while paramagnetic phase is related to the impurity centers. For the samples with fluences of (1.0&1.5) ×1017 ions/cm2 average sizes of the superparamagnetic nanoparticles were calculated from the blocking temperatures TB observed in thermo-magnetic dependences. TÜBITAK, Grant No. 114F359 TÜBITAK / RFBR joint project program, Grant No. 213M524 / 14-02-91374-cT-a. RAS Programme No.32.

  13. Comparison study of transparent RF-sputtered ITO/AZO and ITO/ZnO bilayers for near UV-OLED applications

    NASA Astrophysics Data System (ADS)

    Rezaie, Mahdiyar Nouri; Manavizadeh, Negin; Abadi, Ehsan Mohammadi Nasr; Nadimi, Ebrahim; Boroumand, Farhad Akbari

    2017-01-01

    Hybrid inorganic/organic light-emitting diodes have attracted much attention in the field of luminescent electronics due to the desired incorporation of high optoelectronic features of inorganic materials with the processability and variety of organic polymers. To generate and emit a near ultraviolet (N-UV) ray, wide band gap semiconductors can be applied in the organic light-emitting diodes (OLEDs). In this paper, zinc oxide (ZnO) and aluminum-doped ZnO (AZO) thin films are deposited by radio frequency (RF) sputtering above the ITO electrode and poly [2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylene-vinylene] (MEH-PPV) conjugated polymer is utilized as a complementary p-type semiconductor in OLED structure. The impact of ZnO and AZO thickness on the structural, electrical, optical and morphological properties of ITO/AZO and ITO/ZnO bilayers are scrutinized and compared. Results show that with the enlargement of both ZnO and AZO film thickness, the physical properties are gradually improved resulting in the better quality of transparent conducting thin film. The average electrical resistivity of 8.4 × 10-4 and 1.1 × 10-3 Ω-cm, average sheet resistance of 32.9 and 42.3 Ω/sq, average transmittance of 88.3 and 87.3% and average FOM of 1.0 × 104 and 7.4 × 103 (Ω-cm)-1 are obtained for ITO/AZO and ITO/ZnO bilayers, respectively. Moreover, comparing the results indicates that the strain and the stress within the ITO/AZO bilayer are decreased nearly 19% with respect to ITO/ZnO bilayer which yield higher quality of crystal. Consequently, the physical properties of ITO/AZO bilayer is found to be superior regarding ITO/ZnO bilayer. For fabricated UV-OLEDs, the turn-on voltages, the characteristic energy (Et) and the total concentration of traps (Nt) for the devices with the structures of ITO/ZnO/MEH-PPV/Al and ITO/AZO/MEH-PPV/Al are obtained 12 and 14 V, 0.108 and 0.191 eV, 9.33 × 1016 and 5.22 × 1016 cm-3, respectively. Furthermore, according to the electroluminescence

  14. TiO2-ITO and TiO2-ZnO nanocomposites: application on water treatment

    NASA Astrophysics Data System (ADS)

    Chorfi, H.; Saadoun, M.; Bousselmi, L.; Bessais, B.

    2012-06-01

    One of the most promising ideas to enhance the photocatalytic efficiency of the TiO2 is to couple this photocatalyst with other semiconductors. In this work, we report on the development of photo-catalytic properties of two types of composites based on TiO2 - ITO (Indium Tin Oxide) and TiO2 - ZnO deposited on conventional ceramic substrates. The samples were characterized by X-ray diffraction (XRD) and transmission Electron Microscopy (TEM). The photo-catalytic test was carried out under UV light in order to reduce/oxidize a typical textile dye (Cibacron Yellow). The experiment was carried out in a bench scale reactor using a solution having a known initial dye concentration. After optimization, we found that both nanocomposites exhibit better photocatalytic activity compared to the standard photocatalyst P25 TiO2.

  15. Fabrication of Organic Bulk Heterojunction Solar Cells on Flexible Substrates

    NASA Astrophysics Data System (ADS)

    Calderon, Gabriel; Merced-Sanabria, Milzaida; Carradero-Santiago, Carolyn; Vedrine-Pauléus, Josee

    2015-03-01

    The active layer for the organic solar cells fabricated is composed of P3HT:PCBM, poly(3-hexylthiophene) (P3HT) as electron donor and phenyl-C61-butyric acid methyl ester(PCBM) as electron acceptor. These polymers were used due to their promising characteristics for devices such as bulk heterojunction solar devices. We used polyethylene terephthalate (PET) substrates, a highly flexible plastic, with indium tin oxide (ITO) as the transparent conducting anode for the device, and UV lithography technique to pattern the ITO; this is to facilitate multiple devices on a single substrate. The fabrication process for pattern transfer incorporates developing and etching processes. We diluted the HCl and DI water to etch out the ITO. PEDOT:PSS and active layer of P3HT:PCBM were deposited on (3.0 sq-cm) patterned of ITO/PET by spin coating method. The cathode was thermally evaporated with Al. We characterized the device using a sourcemeter. We also simulated portions of the device using PET on graphene as the substrate.

  16. Martingale integrals over Poissonian processes and the Ito-type equations with white shot noise

    NASA Astrophysics Data System (ADS)

    Zygadło, Ryszard

    2003-10-01

    The construction of the Ito-type stochastic integrals and differential equations for compound Poisson processes is provided. The general martingale and nonanticipating properties of the ordinary (Gaussian) Ito theory are conserved. These properties appear particularly important if the stochastic description has to be proposed according to game theory or the linear relaxation (or the exponential growth) requirements. In contrast to the ordinary Ito theory the (uncorrelated) parametric fluctuation of a definite sign can be still modeled by asymmetric white shot noise, so the general scope of applications is not restricted by the positivity requirements. The possible use of the developed formalism in econophysics is addressed.

  17. Martingale integrals over Poissonian processes and the Ito-type equations with white shot noise.

    PubMed

    Zygadło, Ryszard

    2003-10-01

    The construction of the Ito-type stochastic integrals and differential equations for compound Poisson processes is provided. The general martingale and nonanticipating properties of the ordinary (Gaussian) Ito theory are conserved. These properties appear particularly important if the stochastic description has to be proposed according to game theory or the linear relaxation (or the exponential growth) requirements. In contrast to the ordinary Ito theory the (uncorrelated) parametric fluctuation of a definite sign can be still modeled by asymmetric white shot noise, so the general scope of applications is not restricted by the positivity requirements. The possible use of the developed formalism in econophysics is addressed.

  18. Effects of vacuum annealing and oxygen ion beam bombarding on the electrical and optical properties of ITO films deposited by E-beam evaporation

    NASA Astrophysics Data System (ADS)

    Pan, Yongqiang; Hang, Lingxia

    2012-10-01

    Tin doped indium oxide (ITO) transparent conductive thin films with composition of 10 wt% SnO2 and 89.8 wt% In2O3 have been deposited by electron beam evaporation technique on K9 glass substrates at room temperature. The post annealing processes are done in vacuum with different annealing temperature at 100, 200, 300 and 350 ° for 1 hour, respectively. The oxygen ion energy is 800 eV; oxygen ion beam bombarding time is 10,20,30,40 and 50min, respectively. The results show that conductivity of ITO thin films are improved by increasing annealing temperature. The resistivity of the ITO thin films decrease from 5.2×10-3Ω •cm at room temperature to 1.3×10-3Ω •cm(350 °C). The transmittance values of all samples in the visible range have been increased. As the oxygen ion beam bombarding time increases the resistivity reduce from 5.2×10-3Ω •cm to 9×10-4Ω •cm, the transmittance value improve from 66% to 82% at 550nm. Finally, the vacuum annealing and oxygen ion beam bombarding are done simultaneously, at temperature of 350 °C for 1 hours, ion bombardment time for 40 min. The resistivity of obtained ITO thin film is 7×10-4Ω •cm. The maximum transmittance value is above 89% in the visible wavelength region.

  19. Surface modification in microchip electrophoresis.

    PubMed

    Belder, Detlev; Ludwig, Martin

    2003-11-01

    Different approaches and techniques for surface modification of microfluidic devices applied for microchip electrophoresis are reviewed. The main focus is on the improved electrophoretic separation by reducing analyte-wall interactions and manipulation of electroosmosis. Approaches and methods for permanent and dynamic surface modification of microfluidic devices, manufactured from glass, quartz and also different polymeric substrates, are described.

  20. ITOS VHRR on-board data compression study

    NASA Technical Reports Server (NTRS)

    Gray, R. M.; Davisson, L. D.

    1975-01-01

    Data compression methods for ITOS VHRR data were studied for a tape recorder record-and playback application. A playback period of 9 minutes was assumed with a nominal 18 minute record period for a 2-to-1 compression ratio. Both analog and digital methods were considered with the conclusion that digital methods should be used. Two system designs were prepared. One is a PCM system and the other is an entropy-coded predictive-quantization, sometimes called entropy-coded DPCM or just DPCM, system. Both systems use data management principles to transmit only the necessary data. Both systems use a medium capacity standard tape recorder from specifications provided by the technical officer. The 10 to the 9th power bit capacity of the recorder is the basic limitation on the compression ratio. Both systems achieve the minimum desired 2 to 1 compression ratio. A slower playback rate can be used with the DPCM system due to a higher compression factor for better link performance at a given CNR in terms of bandwidth utilization and error rate. The report is divided into two parts. The first part summarizes the theoretical conclusions of the second part and presents the system diagrams. The second part is a detailed analysis based upon an empirically derived random process model arrived at from specifications and measured data provided by the technical officer.

  1. Degradation of Flexible, ITO-Free Oligothiophene Organic Solar Cells.

    PubMed

    Bormann, Ludwig; Nehm, Frederik; Sonntag, Luisa; Chen, Fan-Yu; Selzer, Franz; Müller-Meskamp, Lars; Eychmüller, Alexander; Leo, Karl

    2016-06-15

    We investigate the degradation of organic solar cells based on an oligothiophene (DCV5T-Me) small molecule donor and the acceptor C60. Two different flexible, transparent bottom electrode types are employed: a transparent metal electrode (TME) and silver nanowires (AgNWs). They exhibit high optical transparency up to 86% and a sheet resistance as low as 12Ω/□. Power conversion efficiencies of 7.0%, 5.7%, and 7.2% on TME, AgNWs, and indium tin oxide (ITO, reference) are reached, respectively. The solar cells are protected against moisture ingress utilizing a flexible alumina thin-film, exhibiting water vapor transmission rates down to 3 × 10(-5) g m(-2) day(-1) at 38 °C and 90% relative humidity (RH). Implementation of this ultrabarrier as top and bottom encapsulation enables fabrication of fully flexible devices. A decrease in PCE to 80% of initial values is observed after 1000 ± 50 h on flexible, encapsulated TME but only 20 ± 5 h on AgNWs in a climate of 38 °C/50% RH. Degradation in AgNW-based devices is attributed to electrode decomposition.

  2. Electrodeposition of Sb2Se3 on indium-doped tin oxides substrate: Nucleation and growth

    NASA Astrophysics Data System (ADS)

    Shi, Xuezhao; zhang, Xin; Tian, Yuan; Shen, Chengmin; Wang, Chunming; Gao, Hong-Jun

    2012-01-01

    The mechanisms related to the initial stages of the nucleation and growth of antimony selenide (Sb2Se3) semiconductor compounds onto the indium-doped tin oxides (ITO) coated glass surface have been investigated using chronoamperometry (CA) technique. The fabrication was conducted from nitric acid bath containing both Sb3+ and SeO2 species at ambient conditions. No underpotential deposition (UPD) of antimony and selenium onto ITO substrate was observed in the investigated systems indicating a weak precursor-substrate interaction. Deposition of antimony and selenium onto ITO substrate occurred with large overvoltage through 3D nucleation and growth mechanism followed by diffusion limited growth. FE-SEM and XRD results show that orthorhombic phase Sb2Se3 particles with their size between 90 and 125 nm were obtained and the atomic ratio for antimony and selenium was 2:2.63 according to the EDX results.

  3. Research of the applications of ITO in microwave-range surface plasmon waves

    NASA Astrophysics Data System (ADS)

    Lai, Senfeng; Wu, Wen; Gu, Wenhua

    2016-09-01

    Because of the electromagnetic field enhancement effect in subwavelength scale, the surface plasmon wave (SPW) has been widely used in beam forming, bio-prospecting, and subwavelength structure design. But most research work is in the visible light or terahertz frequency band, and the surface plasmonic material (SPM) is usually limited to metals. In the microwave band, complex structures have to be used to achieve the desired subwavelength effects, making use of both metal and dielectric materials. In this paper, we propose the excitation of SPW in the microwave range using a simple structure and the material of indium tin oxide (ITO). By measuring the electric field profile during the propagation process, the excitation of SPW in ITO was verified. At the same time, frequency dependence was seen during the propagation process. Therefore, ITO can be a good SPM in the microwave band, just like metals in the visible light band. Considering the transparent characteristics of ITO, it can have many interesting applications.

  4. Development of waterborne oil spill sensor based on printed ITO nanocrystals.

    PubMed

    Koo, Jieun; Jung, Jung-Yeul; Lee, Sangtae; Lee, Moonjin; Chang, Jiho

    2015-09-15

    Oil spill accidents occasionally occur in coastal and ocean environments, and cause critical environmental damage, spoiling the marine habitats and ecosystems. To mitigate the damages, the species and amount of spilled oil should be monitored. In this study, we developed a waterborne oil spill sensor using a printed ITO layer. ITO is a compatible material for salty environments such as oceans because ITO is strong against corrosion. The fabricated sensor was tested using three oils, gasoline, lubricant and diesel, and different oil thicknesses of 0, 5, 10, and 15mm. The results showed that the resistance of the sensor clearly increased with the oil thickness and its electrical resistance. For sustainable sensing applications in marine environments, XRD patterns confirmed that the crystal structure of the ITO sensor did not change and FE-SEM images showed that the surface was clearly maintained after tests.

  5. Efficient inverted polymer solar cells based on conjugated polyelectrolyte and zinc oxide modified ITO electrode

    SciTech Connect

    Yuan, Tao; Zhu, Xiaoguang; Tu, Guoli; Zhou, Lingyu; Zhang, Jian

    2015-02-23

    Efficient inverted polymer solar cells (PSCs) were constructed by utilizing a conjugated polyelectrolyte PF{sub EO}SO{sub 3}Na and zinc oxide to modify the indium tin oxide (ITO) electrode. The ITO electrode modified by PF{sub EO}SO{sub 3}Na and zinc oxide possesses high transparency, increased electron mobility, smoothened surface, and lower work function. PTB7:PC{sub 71}BM inverted PSCs containing the modified ITO electrode achieved a high power conversion efficiency (PCE) of 8.49%, exceeding that of the control device containing a ZnO modified ITO electrode (7.48%). Especially, PCE-10:PC{sub 71}BM inverted polymer solar cells achieved a high PCE up to 9.4%. These results demonstrate a useful approach to improve the performance of inverted polymer solar cells.

  6. On reconstruction of the Ito-like equation from persistent time series

    NASA Astrophysics Data System (ADS)

    Czechowski, Zbigniew

    2013-12-01

    The Langevin equation with finite-range persistence was introduced as a macroscopic model of various geophysical phenomena. The modified histogram procedure (MHP) of reconstruction of the equation from time series was proposed. An efficiency of MHP was tested on artificial persistent time series (with short and long-tail distributions) generated by different Ito-like equations. For an exemplary geophysical time series, the appropriate Ito-like equation was reconstructed.

  7. Laser structuring of conducting films on transparent substrates

    NASA Astrophysics Data System (ADS)

    Račiukaitis, G.; Brikas, M.; Darčianovas, G.; Ruthe, D.; Zimmer, K.

    2007-06-01

    The fast growing market of organic electronics, including organic light-emitting devices (OLED), Solar cells and radio-frequency identification devices (RFID), stimulates development of versatile technologies for patterning the thin-film materials on rigid and flexible substrates. Thin films of the transparent conducting oxides (TCO) are important materials for making transparent contacts, conductors or antennas in such devices. High repetition rate lasers with a short, picosecond pulse duration offer new possibilities for high efficiency structuring of transparent conductors on glass and other substrates. The results of ablation of the indium-tin oxide (ITO) layer on glass and ITO and ZnO layers on polymers with picosecond lasers at various wavelengths are presented. Laser radiation initiated ablation of the material, forming trenches in TCO. UV radiation at the 266 nm provided the widest working window for TCO ablation without damage of the substrate. Subcomponents of the thin-film devices were made in order to test the structuring technology.

  8. Retinoic acid modulates rat Ito cell proliferation, collagen, and transforming growth factor beta production.

    PubMed Central

    Davis, B H; Kramer, R T; Davidson, N O

    1990-01-01

    Recent studies suggest that vitamin A plays an inhibitory role with respect to "activation" of the hepatic Ito cell, a likely effector of hepatic fibrogenesis. Ito cell "activation" during fibrogenesis is characterized by a decrease in intracellular vitamin A and an increase in cellular proliferation and collagen production. To explore the hypothesis that retinoids have the capacity to diminish Ito cell activation, cultured Ito cells were exposed to retinoic acid and its effects assessed on three key features: cell proliferation, collagen protein production and mRNA abundance, and transforming growth factor beta protein production. Retinoic acid was 100-1,000X more potent than retinol with respect to inhibition of Ito cell proliferation. Interstitial collagen and transforming growth factor beta production were also reduced by 10(-6) M retinoic acid. The relative abundance of type I collagen mRNA however, was not significantly altered. By contrast, retinoic acid administration to rats caused a marked reduction in the abundance of type I collagen mRNA in both total hepatic and purified Ito cell RNA. The relative abundance of rat hepatic fibronectin or apolipoprotein E mRNA was not significantly altered. These studies demonstrate that retinoic acid can differentially modulate several key features of hepatic fibrogenesis in vitro and in vivo. Images PMID:2254460

  9. SEMICONDUCTOR MATERIALS: Properties of the ITO layer in a novel red light-emitting diode

    NASA Astrophysics Data System (ADS)

    Yonghui, Zhang; Weiling, Guo; Wei, Gao; Chunwei, Li; Tianping, Ding

    2010-04-01

    An optically transparent electrode, indium tin oxide (ITO) film is fabricated by vacuum E-beam evaporation. The thermal annealing effects on the ITO/GaP contact have been investigated by means of the transmission line model method. Under 435 °C, with rapid thermal annealing for 40 s in N2 ambient, the ITO contact resistance reaches the minimized value of 4.3 × 10-3 Ω · cm2. The results from Hall testing and Auger spectra analysis indicate that the main reasons for the change of the contact resistance are the difference in the concentration of carriers and the diffusion of In, Ga, O. Furthermore, the reliability of AlGaInP LEDs with a 300-nm thickness transparent conducting ITO film is studied. The increase of LED chip voltage results from the degradation of ITO film. Moreover the difference between the thermal expansion coefficient of GaP and ITO results in the invalidation of the LED chip.

  10. Using the Photolysis of Chemically Modified Gel Films Preparing ITO Fine Patterned Thin Films

    NASA Astrophysics Data System (ADS)

    Li, Ying; Zhao, Gaoyang; Zhang, Weihua; Chen, Yuanqing

    2006-06-01

    A novel technique for the fabrication of tin-doped indium oxide (ITO) fine patterning in sol-gel technology is presented in this paper. The fabricated ITO fine patterning could be obtained through a process which combines film fabrication with film etching. ITO films have good comprehensive property of visible transmittance and electrical conductivity, consequently they have been extensively used as coating electrodes. Indium nitrate (In(NO3)3.4.5H2O) and stannic chloride (SnCl4.5H2O) were used as starting materials which were modified with benzytone (BzAcH). The chelate complexes containing indium ions were produced during the process which of forming photosensitive ITO/BzAcH gel films through sol-gel technique. It was found that the gel films are sensitive to both the ultraviolet (UV) light irradiation and their solubility on solvents as well. For example, ethanol was reduced remarkably while the UV absorption peak disappeared with the dissociation of the chelate complexes correspondingly by means of UV-vis and IR spectrophotometers. Utilizing these characteristics, a fine pattern was obtained by irradiation of UV light on the ITO/BzAcH gel films through a pattern mask. of the fine patterned ITO films were heat treated at 500 °C for 15 min, the optical, electrical properties and the surface element components were examined by X-ray photoelectron spectroscopy (XPS) spectra in this work.

  11. Electrochemical detection of vascular endothelial growth factors (VEGFs) using VEGF antibody fragments modified Au NPs/ITO electrode.

    PubMed

    Kim, Gang-Il; Kim, Kyung-Woo; Oh, Min-Kyu; Sung, Yun-Mo

    2010-03-15

    A new electrochemical technique for the detection of vascular endothelial growth factors (VEGFs) as a cancer-related biomarker is presented in this paper. Gold nanoparticles (Au NPs) were self-assembled onto an indium tin oxide (ITO) electrode to prepare a modified sandwich type electrochemical immunoassay platform. VEGF antibodies were cleaved into two half-fragments by 2-mercaptoethylamine-HCl (2-MEA) and the fragments were immobilized onto the Au NP substrates by their thiol groups. Through this strategy, randomly oriented attachment of antibodies was prevented which frequently occurs in a general use of whole antibody and reduces the number of available sites for the attachment of target molecules. VEGF target molecules were applied to the immunoelectrodes and they combined with the antibody fragments covering the Au NP electrode, forming antigen-antibody complexes. Then, ferrocene-tagged antibodies, which release electrons under a proper applied potential, were added to the system and they combined with the VEGF molecules pre-attached to the antibody fragments. The redox current of ferrocene measured by the differential pulse voltammetry (DPV) increased almost linearly from 1.27 x 10(-4) to 4.17 x 10(-4)A according to the increase in the concentration of the VEGF target molecules from 100 to 600 pg/ml. The measured current values represent the concentration of the VEGF since they are proportional to the number of ferrocene molecules which is in turn proportional to the concentration of VEGF target molecules. Using this modified sandwich immunoassay with the Au NP/ITO electrode, VEGFs as low as 100 pg/ml were detected with high specificity.

  12. Electron beam induced damage in ITO coated Kapton. [Indium Tin Oxide

    NASA Technical Reports Server (NTRS)

    Krainsky, I.; Gordon, W. L.; Hoffman, R. W.

    1981-01-01

    Data for the stability of thin conductive indium tin oxide films on 0.003 inch thick Kapton substrates during exposure of the surface to electron beams are reported. The electron beam energy was 3 keV and the diameter was about 0.8 mm. Thermal effects and surface modifications are considered. For primary current greater than 0.6 microamperes, an obvious dark discoloration with diameter approximately that of the beam was produced. The structure of the discolored region was studied with the scanning electron microscope, and the findings are stated. Surface modifications were explored by AES, obtaining spectra and secondary emission coefficient as a function of time for different beam intensities. In all cases beam exposure results in a decrease of the secondary yield but because of thermal effects this change, as well as composition changes, cannot be directly interpreted in terms of electron beam dosage.

  13. Behavior modification.

    PubMed

    Pelham, W E; Fabiano, G A

    2000-07-01

    Attention deficit/hyperactivity disorder (ADHD) is a chronic and substantially impairing disorder. This means that treatment must also be chronic and substantial. Behavior Modification, and in many cases, the combination of behavior modification and stimulant medication, is a valid, useful treatment for reducing the pervasive impairment experienced by children with ADHD. Based on the research evidence reviewed, behavior modification should be the first line of treatment for children with ADHD.

  14. Laser patterning of very thin indium tin oxide thin films on PET substrates

    NASA Astrophysics Data System (ADS)

    McDonnell, C.; Milne, D.; Prieto, C.; Chan, H.; Rostohar, D.; O'Connor, G. M.

    2015-12-01

    This work investigates the film removal properties of 30 nm thick Indium Tin Oxide (ITO) thin films, on flexible polyethylene terephthalate (PET) substrates, using 355, 532 and 1064 nm nanosecond pulses (ns), and 343 and 1064 nm femtosecond pulses. The ablation threshold was found to be dependent on the applied wavelength and pulse duration. The surface topography of the laser induced features were examined using atomic force microscopy across the range of wavelengths and pulse durations. The peak temperature, strain and stress tensors were examined in the film and substrate during laser heating, using finite element computational methods. Selective removal of the thin ITO film from the polymer substrate is possible at all wavelengths except at 266 nm, were damage to substrate is observed. The damage to the substrate results in periodic surface structures (LIPPS) on the exposed PET, with a period of twice the incident wavelength. Fragmented crater edges are observed at all nanosecond pulse durations. Film removal using 1030 nm femtosecond pulses results in clean crater edges, however, minor 5 nm damage to the substrate is also observed. The key results show that film removal for ITO on PET, is through film de-lamination across all wavelengths and pulse durations. Film de-lamination occurs due to thermo-elastic stress at the film substrate interface region, as the polymer substrate expands under heating from direct laser absorption and heat conduction across the film substrate interface.

  15. High quality nitrogen-doped zinc oxide thin films grown on ITO by sol-gel method

    NASA Astrophysics Data System (ADS)

    Pathak, Trilok Kumar; Kumar, Vinod; Purohit, L. P.

    2015-11-01

    Highly transparent N-doped ZnO thin films were deposited on ITO coated corning glass substrate by sol-gel method. Ammonium nitrate was used as a dopant source of N with varying the doping concentration 0, 0.5, 1.0, 2.0 and 3.0 at%. The DSC analysis of prepared NZO sols is observed a phase transition at 150 °C. X-ray diffraction pattern showed the preferred (002) peak of ZnO, which was deteriorated with increased N concentrations. The transmittance of NZO thin films was observed to be ~88%. The bandgap of NZO thin films increased from 3.28 to 3.70 eV with increased N concentration from 0 to 3 at%. The maximum carrier concentration 8.36×1017 cm-3 and minimum resistivity 1.64 Ω cm was observed for 3 at% N doped ZnO thin films deposited on glass substrate. These highly transparent ZnO thin films can be used as a window layer in solar cells and optoelectronic devices.

  16. General observation of the memory effect in metal-insulator-ITO structures due to indium diffusion

    NASA Astrophysics Data System (ADS)

    Wu, Xiaojing; Xu, Huihua; Wang, Yu; Rogach, Andrey L.; Shen, Yingzhong; Zhao, Ni

    2015-07-01

    Resistive random access memory (RRAM) devices based on metal oxides, organic molecules and inorganic nanocrystals (NCs) have been studied extensively in recent years. Different memory switching mechanisms have been proposed and shown to be closely related to the device architectures. In this work, we demonstrate that the use of an ITO/active layer/InGa structure can yield nonvolatile resistive memory behavior in a variety of active materials, including polymers, organic small molecules, and colloidal NCs. Through the electrode material and thickness-dependent study, we show that the ON state of the devices is associated with filamentary conduction induced by indium diffusion from the ITO electrode, occurring mostly within around 40-50 nm from the ITO/active layer interface. A negative differential resistance (NDR) regime is observed during transition from the ON to OFF state, and is explained by the space charge limited current (SCLC) effect due to hole injection at the ITO/active layer interface. Our study reveals the impact of indium diffusion at the ITO/active layer interface, an important factor that should be taken into consideration when designing thin printed RRAM devices.

  17. Hypomelanosis of Ito with a trisomy 2 mosaicism: a case report

    PubMed Central

    2014-01-01

    Introduction Hypomelanosis of Ito is a rare neurocutaneous disorder, characterized by streaks and swirls of hypopigmentation following the lines of Blaschko that may be associated to systemic abnormalities involving the central nervous system and musculoskeletal system. Despite the preponderance of reported sporadic hypomelanosis of Ito, few reports of familial hypomelanosis of Ito have been described. Case presentation A 6-month-old Caucasian girl presented with unilateral areas of hypomelanosis distributed on the left half of her body and her father presented with similar mosaic hypopigmented lesions on his upper chest. Whereas both blood karyotypes obtained from peripheral lymphocyte cultures were normal, a 16% trisomy 2 mosaicism was found in cultured skinfibroblasts derived from a hypopigmented skin area of her father. Conclusions Familial cases of hypomelanosis of Ito are very rare and can occur in patients without systemic involvement. Hypomelanosis of Ito constitutes a non-specific diagnostic definition including different clinical entities with a wide phenotypic variability, either sporadic or familial. Unfortunately, a large number of cases remain misdiagnosed due to both diagnostic challenges and controversial issues on cutaneous biopsies in the pediatric population. PMID:25301139

  18. UV light emitting transparent conducting tin-doped indium oxide (ITO) nanowires.

    PubMed

    Gao, J; Chen, R; Li, D H; Jiang, L; Ye, J C; Ma, X C; Chen, X D; Xiong, Q H; Sun, H D; Wu, T

    2011-05-13

    Multifunctional single crystalline tin-doped indium oxide (ITO) nanowires with tuned Sn doping levels are synthesized via a vapor transport method. The Sn concentration in the nanowires can reach 6.4 at.% at a synthesis temperature of 840 °C, significantly exceeding the Sn solubility in ITO bulks grown at comparable temperatures, which we attribute to the unique feature of the vapor-liquid-solid growth. As a promising transparent conducting oxide nanomaterial, layers of these ITO nanowires exhibit a sheet resistance as low as 6.4 Ω/[Symbol: see text] and measurements on individual nanowires give a resistivity of 2.4 × 10(-4) Ω cm with an electron density up to 2.6 × 10(20) cm(-3), while the optical transmittance in the visible regime can reach ∼ 80%. Under the ultraviolet excitation the ITO nanowire samples emit blue light, which can be ascribed to transitions related to defect levels. Furthermore, a room temperature ultraviolet light emission is observed in these ITO nanowires for the first time, and the exciton-related radiative process is identified by using temperature-dependent photoluminescence measurements.

  19. Improved ITOS attitude control system with Hall generator brushless motor and earth-splitting technique

    NASA Technical Reports Server (NTRS)

    Peacock, W. M.

    1971-01-01

    The ITOS with an improved attitude control system is described. A Hall generator brushless dc torque motor will replace the brush dc torque motor on ITOS-I and ITOS-A (NOAA-1). The four attitude horizon sensors will be replaced with two CO2 sensors for better horizon definition. An earth horizon splitting technique will be used to keep the earth facing side of the satellite toward earth even if the desired circular orbit is not achieved. The external appearance of the pitch control subsystem differs from TIROS-M (ITOS-1) and ITOS-A (NOAA-1) in that two instead of one pitch control electronics (PCE) boxes are used. Two instead of four horizon sensors will be used and one instead of two mirrors will be used for sensor scanning. The brushless motor will eliminate the requirement for brushes, strain gages and the telemetry for the brush wear. A single rotating flywheel, supported by a single bearing provides the gyroscopic stability and the required momentum interchange to keep one side of the satellite facing the earth. Magnetic torquing against the earth's magnetic field eliminates the requirement for expendable propellants which would limit satellite life in orbit.

  20. Involvement of flocculin in negative potential-applied ITO electrode adhesion of yeast cells

    PubMed Central

    Koyama, Sumihiro; Tsubouchi, Taishi; Usui, Keiko; Uematsu, Katsuyuki; Tame, Akihiro; Nogi, Yuichi; Ohta, Yukari; Hatada, Yuji; Kato, Chiaki; Miwa, Tetsuya; Toyofuku, Takashi; Nagahama, Takehiko; Konishi, Masaaki; Nagano, Yuriko; Abe, Fumiyoshi

    2015-01-01

    The purpose of this study was to develop novel methods for attachment and cultivation of specifically positioned single yeast cells on a microelectrode surface with the application of a weak electrical potential. Saccharomyces cerevisiae diploid strains attached to an indium tin oxide/glass (ITO) electrode to which a negative potential between −0.2 and −0.4 V vs. Ag/AgCl was applied, while they did not adhere to a gallium-doped zinc oxide/glass electrode surface. The yeast cells attached to the negative potential-applied ITO electrodes showed normal cell proliferation. We found that the flocculin FLO10 gene-disrupted diploid BY4743 mutant strain (flo10Δ /flo10Δ) almost completely lost the ability to adhere to the negative potential-applied ITO electrode. Our results indicate that the mechanisms of diploid BY4743 S. cerevisiae adhesion involve interaction between the negative potential-applied ITO electrode and the Flo10 protein on the cell wall surface. A combination of micropatterning techniques of living single yeast cell on the ITO electrode and omics technologies holds potential of novel, highly parallelized, microchip-based single-cell analysis that will contribute to new screening concepts and applications. PMID:26187908

  1. Surface modification of Ca-α-SiAlON: Eu2+ phosphor particles by SiO2 coating and fabrication of its deposit by electrophoretic deposition (EPD) process

    NASA Astrophysics Data System (ADS)

    Zhang, Chenning; Uchikoshi, Tetsuo; Kitabatake, Takuya; Sakka, Yoshio; Hirosaki, Naoto

    2013-09-01

    Ca-α-SiAlON: Eu2+ phosphor powder was modified with a SiO2 coating by the adsorption, hydrolysis, and polymerization of the TEOS precursor. Through the modification for the surface defects of the particles by the SiO2 coating, the photoluminescence (PL) emission could be significantly strengthened in the SiO2-coated Ca-α-SiAlON: Eu2+ powder. The electrophoretic deposition (EPD) technique was employed to fabricate the deposit layer on ITO glass using the SiO2 coated phosphor powder. The prepared deposit exhibited a uniform surface morphology with strong adhesion to the substrate. The SiO2-coated Ca-α-SiAlON: Eu2+ powder indicates a potential application when used in pseudo white light-emitting diodes (LEDs) devices.

  2. Parametrization of optical properties of indium-tin-oxide thin films by spectroscopic ellipsometry: Substrate interfacial reactivity

    NASA Astrophysics Data System (ADS)

    Losurdo, M.; Giangregorio, M.; Capezzuto, P.; Bruno, G.; de Rosa, R.; Roca, F.; Summonte, C.; Plá, J.; Rizzoli, R.

    2002-01-01

    Indium-tin-oxide (ITO) films deposited by sputtering and e-gun evaporation on both transparent (Corning glass) and opaque (c-Si, c-Si/SiO2) substrates and in c-Si/a-Si:H/ITO heterostructures have been analyzed by spectroscopic ellipsometry (SE) in the range 1.5-5.0 eV. Taking the SE advantage of being applicable to absorbent substrate, ellipsometry is used to determine the spectra of the refractive index and extinction coefficient of the ITO films. The effect of the substrate surface on the ITO optical properties is focused and discussed. To this aim, a parametrized equation combining the Drude model, which considers the free-carrier response at the infrared end, and a double Lorentzian oscillator, which takes into account the interband transition contribution at the UV end, is used to model the ITO optical properties in the useful UV-visible range, whatever the substrate and deposition technique. Ellipsometric analysis is corroborated by sheet resistance measurements.

  3. Durability of ITO-MgF2 Films for Space-Inflatable Polymer Structures

    NASA Technical Reports Server (NTRS)

    Kerslake, Thomas W.; Waters, Deborah L.; Schieman, David A.; Hambourger, Paul D.

    2003-01-01

    This paper presents results from ITO-MgF2 film durability evaluations that included tape peel, fold, thermal cycle, and AO exposure testing. Polymer coupon preparation is described as well as ITO-MgF2 film deposition equipment, procedures and film characterization. Durability testing methods are also described. The pre- and post-test condition of the films is assessed visually, microscopically, and electrically. Results show that at 500 ITO - 9 vol% MgF2 film is suitable to protect polymer surfaces, such as those used in space-inflatable structures of the PowerSphere microsatellite concept, during a 1-year Earth orbiting mission. Future plans for ground-based and orbital testing of this film are also discussed.

  4. Multifractal analysis of visibility graph-based Ito-related connectivity time series.

    PubMed

    Czechowski, Zbigniew; Lovallo, Michele; Telesca, Luciano

    2016-02-01

    In this study, we investigate multifractal properties of connectivity time series resulting from the visibility graph applied to normally distributed time series generated by the Ito equations with multiplicative power-law noise. We show that multifractality of the connectivity time series (i.e., the series of numbers of links outgoing any node) increases with the exponent of the power-law noise. The multifractality of the connectivity time series could be due to the width of connectivity degree distribution that can be related to the exit time of the associated Ito time series. Furthermore, the connectivity time series are characterized by persistence, although the original Ito time series are random; this is due to the procedure of visibility graph that, connecting the values of the time series, generates persistence but destroys most of the nonlinear correlations. Moreover, the visibility graph is sensitive for detecting wide "depressions" in input time series.

  5. Low-Work-Function, ITO-Free Transparent Cathodes for Inverted Polymer Solar Cells.

    PubMed

    Xue, Zhichao; Liu, Xingyuan; Lv, Ying; Zhang, Nan; Guo, Xiaoyang

    2015-09-16

    A low-work-function, indium tin oxide (ITO)-free transparent cathode having a tin oxide (SnOX)/Ag/SnOX/bismuth oxide (Bi2O3) (SASB) structure is developed without using annealing treatment. This represents the first time that Bi2O3 has been introduced to lower the work function of transparent electrodes. The SASB transparent cathode exhibits excellent photoelectric properties with a maximum transmittance of ∼88%, a low sheet resistance of ∼9.0 Ω·sq(-1), and a suitable work function of 4.22 eV that matches the lowest unoccupied molecular orbital level of the acceptor for exacting electrons efficiently. The power conversion efficiency of the polymer solar cell with the SASB electrode is 6.21%, which is comparable to that of ITO-based devices. The results indicate that SASB is a good alternative to ITO as transparent cathodes in optoelectronic devices.

  6. Ground radiation tests and flight atomic oxygen tests of ITO protective coatings for Galileo Spacecraft

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.; Maag, Carl R.

    1986-01-01

    Radiation simulation tests (protons and electrons) were performed along with atomic oxygen flight tests aboard the Shuttle to space qualify the surface protective coatings. The results, which contributed to the selection of indium-tin-oxide (ITO) coated polyester as the material for the thermal blankets of the Galileo Spacecraft, are given here. Two candidate materials, polyester and Fluorglas, were radiation-tested to determine changes at simulated Jovian radiation levels. The polyester exhibited a smaller weight loss (2.8) than the Fluorglas (8.8 percent). Other changes of polyester are given. During low-earth orbit, prior to transit to Jupiter, the thermal blankets would be exposed to atomic oxygen. Samples of uncoated and ITO-coated polyesters were flown on the Shuttle. Qualitative results are given which indicated that the ITO coating protected the underlying polyester.

  7. Designing interlayers to improve the mechanical reliability of transparent conductive oxide coatings on flexible substrates

    SciTech Connect

    Kim, Eun-Hye; Yang, Chan-Woo; Park, Jin-Woo

    2012-05-01

    In this study, we investigate the effect of interlayers on the mechanical properties of transparent conductive oxide (TCO) on flexible polymer substrates. Indium tin oxide (ITO), which is the most widely used TCO film, and Ti, which is the most widely used adhesive interlayer, are selected as the coating and the interlayer, respectively. These films are deposited on the polymer substrates using dc-magnetron sputtering to achieve varying thicknesses. The changes in the following critical factors for film cracking and delamination are analyzed: the internal stress ({sigma}{sup i}) induced in the coatings during deposition using a white light interferometer, the crystallinity using a transmission electron microscope, and the surface roughness of ITO caused by the interlayer using an atomic force microscope. The resistances to the cracking and delamination of ITO are evaluated using a fragmentation test. Our tests and analyses reveal the important role of the interlayers, which significantly reduce the compressive {sigma}{sup i} that is induced in the ITO and increase the resistance to the buckling delamination of the ITO. However, the relaxation of {sigma}{sup i} is not beneficial to cracking because there is less compensation for the external tension as {sigma}{sup i} further decreases. Based on these results, the microstructural control is revealed as a more influential factor than {sigma}{sup i} for improving crack resistance.

  8. Fatigue properties of Graphene interconnects on flexible substrates

    NASA Astrophysics Data System (ADS)

    Paradee, Gary

    This thesis represents the first determination of the fatigue behavior of Graphene as interconnect material electronic components on flexible substrates. The potential application of this interconnect material is for displays on flexible substrates where fatigue resistance is required due to the stress placed on the interconnect during mechanical bending. As the display is cyclically deformed (fatigued) during normal operation, cracks in the interconnect layer initiate and propagate leading to the lineout failure condition. The major contribution of this work is to show that Graphene is a superior interconnect material to the present state of the art Indium Tin Oxide (ITO) due to its electrical, optical and mechanical properties. The experimental approach in this thesis is based on Graphene samples which were fabricated on Silicon Nitrite (Si3N4)/Polyethylene Naphthalate (PEN) substrates. For comparison, both patterned and uniform ITO films ITO films on Si3N4/PEN were fabricated. The results of the in-depth characterization of Graphene are reported and based on Atomic Force Microscopy (AFM), Raman Spectroscopy and Scanning Electron Microscopy (SEM) are reported. The fatigue characteristics of ITO were determined at stress amplitudes ranging from 2000 MPa to 400 MPa up to 5000 cycles. The fatigue characteristics of Graphene were determined at stress amplitudes ranging from 80 GPa to 40 GPa up to 5000 cycles. The fatigue S-N curves were determined and showed that Graphene's endurance limit is 40 GPa. Beyond the endurance limit, there is no observable high cycle or low cycle fatigue indication for Graphene on a flexible substrate such as PEN. The microstructural analysis by SEM and AFM did not reveal normal fatigue crack growth and propagation. This thesis presents the first comprehensive behavior of Graphene in a bending fatigue stress environment present in numerous flexible electronic applications. The design and stress environments for safe operation has been

  9. Home Modification

    MedlinePlus

    ... it is important to consider certain safety modifications. Adaptations such as those in the following list can ... The importance of a Consumer Perspective in Home Adaptation of Alzheimer’s Households” (Chapter 6 pp 91-112) ...

  10. High quality non-rectifying contact of ITO with both Ni and n-type GaAs

    NASA Astrophysics Data System (ADS)

    Qingsong, Wang; Masao, Ikeda; Ming, Tan; Pan, Dai; Yuanyuan, Wu; Shulong, Lu; Hui, Yang

    2015-05-01

    We report the specific contact resistance for ITO with both metal and a semiconductor. Good quality ITO was deposited by electron beam evaporation with the resistivity of 2.32 × 10-4 Ω·cm and an averaged transmittance of 92.8% in the visible light region. The circular transmission line model (c-TLM) method was used to evaluate and compare the properties of the ITO/metal and ITO/semiconductor ohmic contacts. The lowest specific contact resistance of the ITO/Ni is 2.81 × 10-6 Ω·cm2, while that of ITO/n-GaAs is 7 × 10-5 Ω·cm2. This is the best ohmic contact between ITO and n-GaAs ever reported. These results suggest that good quality ITO has strong potential to be used to realize highly efficient solar cells. Project supported by the National Natural Science Foundation (Nos. 61176128, 61376081), the Knowledge Innovation Project of the CAS (No. Y2BAQ11001), and the SINANO SONY Joint Program (Nos. Y1AAQ11002, Y2AAQ11004).

  11. A cracked polymer templated metal network as a transparent conducting electrode for ITO-free organic solar cells.

    PubMed

    Rao, K D M; Hunger, Christoph; Gupta, Ritu; Kulkarni, Giridhar U; Thelakkat, Mukundan

    2014-08-07

    We report a highly transparent, low resistance Ag metal network templated by a cracked polymer thin film and its incorporation in an organic solar cell. The performance of this scalable metallic network is comparable to that of conventional ITO electrodes. This is a general approach to replace ITO in diverse thin film devices.

  12. Application of ITO/Al reflectors for increasing the efficiency of single-crystal silicon solar cells

    SciTech Connect

    Kopach, V. R.; Kirichenko, M. V. Khrypunov, G. S.; Zaitsev, R. V.

    2010-06-15

    It is shown that an increase in the efficiency and manufacturability of single-junction single-crystal silicon photoelectric converters of solar energy requires the use of a back-surface reflector based on conductive transparent indium-tin oxide (ITO) 0.25-2 {mu}m thick. To increase the efficiency and reduce the sensitivity to the angle of light incidence on the photoreceiving surface of multijunction photoelectric converters with vertical diode cells based on single-crystal silicon, ITO/Al reflectors with an ITO layer >1 {mu}m thick along vertical boundaries of diode cells should be fabricated. The experimental study of multijunction photoelectric converters with ITO/Al reflectors at diode cell boundaries shows the necessity of modernizing the used technology of ITO layers to achieve their theoretically calculated thickness.

  13. A novel molecularly imprinted sensor for selectively probing imipramine created on ITO electrodes modified by Au nanoparticles.

    PubMed

    Xu, Xiaoli; Zhou, Guoliang; Li, Huixiang; Liu, Qian; Zhang, Song; Kong, Jilie

    2009-04-15

    A sensitive molecularly imprinted electrochemical sensor was created for selective detection of a tricyclic antidepressant imipramine by combination of Au nanoparticles (Au-NPs) with a thin molecularly imprinted film. The sensor was fabricated onto the indium tin oxide (ITO) electrode via stepwise modification of Au-NPs by self-assembly and a thin film of molecularly imprinted polymers (MIPs) via sol-gel technology. It was observed that the molecularly imprinted film displayed excellent selectivity towards the target molecule imipramine. Meanwhile, the introduced Au-NPs exhibited noticeable catalytic activities towards imipramine oxidation, which remarkably enhanced the sensitivity of the imprinted film. Due to such combination, the as-prepared sensor responded quickly to imipramine, within only 1 min of incubation. The differential voltammetric anodic peak current was linear to the logarithm of imipramine concentration in the range from 5.0x10(-6) to 1.0x10(-3) mol L(-1), and the detection limits obtained was 1.0x10(-9) mol L(-1). This method proposed was successfully applied to the determination of imipramine in drug tablets, and proven to be reliable compared with conventional UV method. These results reveal that such a sensor fulfills the selectivity, sensitivity, speed and simplicity requirements for imipramine detection, and provides possibilities of clinical application in physiological fluids.

  14. RNA modification in Cajal bodies.

    PubMed

    Meier, U Thomas

    2016-10-24

    Aside from nucleoli, Cajal bodies (CBs) are the best-characterized organelles of mammalian cell nuclei. Like nucleoli, CBs concentrate ribonucleoproteins (RNPs), in particular, spliceosomal small nuclear RNPs (snRNPs) and small nucleolar RNPs (snoRNPs). In one of the best-defined functions of CBs, most of the snoRNPs are involved in site-specific modification of snRNAs. The two major modifications are pseudouridylation and 2'-O-methylation that are guided by the box H/ACA and C/D snoRNPs, respectively. This review details the modifications, their function, the mechanism of modification, and the machineries involved. We dissect the different classes of noncoding RNAs that meet in CBs, guides and substrates. Open questions and conundrums, often raised and appearing due to experimental limitations, are pointed out and discussed. The emphasis of the review is on mammalian CBs and their function in modification of noncoding RNAs.

  15. Ru/ITO: a carbon-free cathode for nonaqueous Li-O2 battery.

    PubMed

    Li, Fujun; Tang, Dai-Ming; Chen, Yong; Golberg, Dmitri; Kitaura, Hirokazu; Zhang, Tao; Yamada, Atsuo; Zhou, Haoshen

    2013-10-09

    Ru nanoparticles deposited on a conductive support indium tin oxide (Ru/ITO) were applied as a carbon-free cathode in a nonaqueous Li-O2 battery. The Li-O2 battery with Ru/ITO showed much lower charging overpotentials and better cycling performance at 0.15 mA/cm(2) than those with Super P (SP) and SP loaded with Ru nanoparticles (Ru/SP) as the cathodes. The carbon-free cathode Ru/ITO can effectively reduce formation of Li2CO3 or other Li carbonates in a discharging process, which cannot be completely decomposed upon charging, in comparison with the carbon based cathode. The improved performance of Ru/ITO can be attributed to the superior catalytic activity of Ru nanoparticles toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) and the absence of carbon that has been reported to react with Li2O2 to form Li2CO3.

  16. Performance enhancement of ITO/oxide/semiconductor MOS-structure silicon solar cells with voltage biasing

    PubMed Central

    2014-01-01

    In this study, we demonstrate the photovoltaic performance enhancement of a p-n junction silicon solar cell using a transparent-antireflective ITO/oxide film deposited on the spacing of the front-side finger electrodes and with a DC voltage applied on the ITO-electrode. The depletion width of the p-n junction under the ITO-electrode was induced and extended while the absorbed volume and built-in electric field were also increased when the biasing voltage was increased. The photocurrent and conversion efficiency were increased because more photo-carriers are generated in a larger absorbed volume and because the carriers transported and collected more effectively due to higher biasing voltage effects. Compared to a reference solar cell (which was biased at 0 V), a conversion efficiency enhancement of 26.57% (from 12.42% to 15.72%) and short-circuit current density enhancement of 42.43% (from 29.51 to 42.03 mA/cm2) were obtained as the proposed MOS-structure solar cell biased at 2.5 V. In addition, the capacitance-volt (C-V) measurement was also used to examine the mechanism of photovoltaic performance enhancement due to the depletion width being enlarged by applying a DC voltage on an ITO-electrode. PMID:25593550

  17. Use of Whole Exome Sequencing for the Identification of Ito-Based Arrhythmia Mechanism and Therapy

    PubMed Central

    Sturm, Amy C; Kline, Crystal F; Glynn, Patric; Johnson, Benjamin L; Curran, Jerry; Kilic, Ahmet; Higgins, Robert S D; Binkley, Philip F; Janssen, Paul M L; Weiss, Raul; Raman, Subha V; Fowler, Steven J; Priori, Silvia G; Hund, Thomas J; Carnes, Cynthia A; Mohler, Peter J

    2015-01-01

    Background Identified genetic variants are insufficient to explain all cases of inherited arrhythmia. We tested whether the integration of whole exome sequencing with well-established clinical, translational, and basic science platforms could provide rapid and novel insight into human arrhythmia pathophysiology and disease treatment. Methods and Results We report a proband with recurrent ventricular fibrillation, resistant to standard therapeutic interventions. Using whole-exome sequencing, we identified a variant in a previously unidentified exon of the dipeptidyl aminopeptidase-like protein-6 (DPP6) gene. This variant is the first identified coding mutation in DPP6 and augments cardiac repolarizing current (Ito) causing pathological changes in Ito and action potential morphology. We designed a therapeutic regimen incorporating dalfampridine to target Ito. Dalfampridine, approved for multiple sclerosis, normalized the ECG and reduced arrhythmia burden in the proband by >90-fold. This was combined with cilostazol to accelerate the heart rate to minimize the reverse-rate dependence of augmented Ito. Conclusions We describe a novel arrhythmia mechanism and therapeutic approach to ameliorate the disease. Specifically, we identify the first coding variant of DPP6 in human ventricular fibrillation. These findings illustrate the power of genetic approaches for the elucidation and treatment of disease when carefully integrated with clinical and basic/translational research teams. PMID:26015324

  18. Performance enhancement of ITO/oxide/semiconductor MOS-structure silicon solar cells with voltage biasing.

    PubMed

    Ho, Wen-Jeng; Huang, Min-Chun; Lee, Yi-Yu; Hou, Zhong-Fu; Liao, Changn-Jyun

    2014-01-01

    In this study, we demonstrate the photovoltaic performance enhancement of a p-n junction silicon solar cell using a transparent-antireflective ITO/oxide film deposited on the spacing of the front-side finger electrodes and with a DC voltage applied on the ITO-electrode. The depletion width of the p-n junction under the ITO-electrode was induced and extended while the absorbed volume and built-in electric field were also increased when the biasing voltage was increased. The photocurrent and conversion efficiency were increased because more photo-carriers are generated in a larger absorbed volume and because the carriers transported and collected more effectively due to higher biasing voltage effects. Compared to a reference solar cell (which was biased at 0 V), a conversion efficiency enhancement of 26.57% (from 12.42% to 15.72%) and short-circuit current density enhancement of 42.43% (from 29.51 to 42.03 mA/cm(2)) were obtained as the proposed MOS-structure solar cell biased at 2.5 V. In addition, the capacitance-volt (C-V) measurement was also used to examine the mechanism of photovoltaic performance enhancement due to the depletion width being enlarged by applying a DC voltage on an ITO-electrode.

  19. Laser Direct Ablation of Indium Tin Oxide Films on Both Sides of Various Substrates.

    PubMed

    Oh, Gi Taek; Kwon, Sang Jik; Han, Jae-Hee; Cho, Eou Sik

    2015-03-01

    We demonstrate ablation of indium tin oxide (ITO) films onto both glass and polyethylene terephthalate (PET) substrates, using a Q-switched diode-pumped neodymium-doped yttrium vanadate laser (Nd:YVO4, λ = 1064 nm) incident on both the front and back sides of the substrate. From scanning electron microscope (SEM) images and depth profile data, ITO patterns that were laser-ablated onto glass from the back side showed a larger abrupt change in the ablated line width than those ablated from the front. However, there were only slight differences in ablated line widths due to the direction of the incident laser beam. We provide a possible explanation in terms of several factors: dispersion of laser beam energy through the substrate, overlapping of each laser beam spot due to scanning speed, and the thickness of glass and PET substrates.

  20. Power gain assessment of ITO based Transparent Gate Recessed Channel (TGRC) MOSFET for RF/wireless applications

    NASA Astrophysics Data System (ADS)

    Kumar, Ajay; Gupta, Neha; Chaujar, Rishu

    2016-03-01

    In this work, power gain assessment and intrinsic delay of Transparent Gate Recessed Channel (TGRC) MOSFET have been observed for RF applications and the results so obtained have been compared with Conventional Recessed Channel (CRC) MOSFET. Simulation results show that TGRC architecture has significantly improved the power gains in terms of maximum available power gain (Gma), maximum transducer power gain (GMT), maximum stable power gain (Gms) and appreciable reduction in intrinsic delay as compared to CRC-MOSFET owing to indium tin oxide (ITO) in recessed channel as a conducting gate material and thus providing its efficacy for low power switching applications. Further, effect of gate length scaling has also been observed on TGRC MOSFET and it has been found that the cut-off frequency (fT) and maximum oscillator frequency (fMAX) enhances by 66% and 36% respectively as channel length scales down to 20 nm. Further, the effect of negative junction depth, oxide thickness and substrate doping have also been investigated for TGRC-MOSFET. This TCAD assessment has been done at frequencies of several THz which fortify its use for high frequency RF/wireless applications.

  1. ITO-free organic light-emitting diodes with MoO3/Al/MoO3 as semitransparent anode fabricated using thermal deposition method

    NASA Astrophysics Data System (ADS)

    Lu, Hsin-Wei; Huang, Ching-Wen; Kao, Po-Ching; Chu, Sheng-Yuan

    2015-08-01

    In this paper, semitransparent electrodes with the structure substrate/MoO3/Al/MoO3 (OMO) were fabricated via the thermal deposition method for use as the anode in organic light-emitting diodes (OLEDs). The optical transmittance of the metal layer was enhanced by depositing metal oxidation (MoO3) and metal (Al) layers. The optimal thickness of the Al thin films was determined to be 15 nm for high optical transmittance and good electrical conductivity. The optimized films show the typical sheet resistance of 7 Ω/sq and a high transmittance of 70% at 550 nm. The indium-tin-oxide (ITO)-free OLEDs with the fabricated composite anodes on a glass substrate exhibited the high luminance and current efficiency of 21,750 cd/m2 and 3.18 cd/A, respectively. In addition, bending effects on the polyethersulfone (PES) substrate/MoO3/Al/MoO3 and PES substrate/MoO3/Al structures were investigated. Cracks formed on the surface of the samples with a bending radius smaller than or equal to 1 cm. MoO3 covering the Al layer modifies the surface of the electrode and enhances durability. The surface roughness of the bi-layer films was higher than that of the tri-layer films. Therefore, OLEDs with OMO anode outperform those with bi-layer films anode.

  2. Metal-insulator transition in tin doped indium oxide (ITO) thin films: Quantum correction to the electrical conductivity

    NASA Astrophysics Data System (ADS)

    Kaushik, Deepak Kumar; Kumar, K. Uday; Subrahmanyam, A.

    2017-01-01

    Tin doped indium oxide (ITO) thin films are being used extensively as transparent conductors in several applications. In the present communication, we report the electrical transport in DC magnetron sputtered ITO thin films (prepared at 300 K and subsequently annealed at 673 K in vacuum for 60 minutes) in low temperatures (25-300 K). The low temperature Hall effect and resistivity measurements reveal that the ITO thin films are moderately dis-ordered (kFl˜1; kF is the Fermi wave vector and l is the electron mean free path) and degenerate semiconductors. The transport of charge carriers (electrons) in these disordered ITO thin films takes place via the de-localized states. The disorder effects lead to the well-known `metal-insulator transition' (MIT) which is observed at 110 K in these ITO thin films. The MIT in ITO thin films is explained by the quantum correction to the conductivity (QCC); this approach is based on the inclusion of quantum-mechanical interference effects in Boltzmann's expression of the conductivity of the disordered systems. The insulating behaviour observed in ITO thin films below the MIT temperature is attributed to the combined effect of the weak localization and the electron-electron interactions.

  3. 2,4-dinitrophenol acutely inhibits rabbit atrial Ca2+ -sensitive Cl- current (I(TO2)).

    PubMed

    Ravesloot, J H; Rombouts, E

    2000-10-01

    We investigated the effects of 2,4-dinitrophenol (DNP), the uncoupler of mitochondrial oxidative phosphorylation, on the Ca2+ -sensitive Cl- current component of the transient outward current (I(TO2)). Amphotericin B perforated-patch, whole-cell patch-clamp technique was employed (35 degrees C) using enzymatically isolated single rabbit atrial myocytes. We defined I(TO2) as the amplitude of the 2 mM 4-aminopyridine resistant transient outward current sensitive to anthracene-9-carboxylic acid (A9C). Between +5 and +45 mV, 0.2 mM A9C inhibited I(TO2) by approximately 70% (n = 13). Within 30 s after application of 0.2 mM DNP, both normal I(TO2) transients (n = 8) and the I(TO2) transients that remained after A9C treatment (n = 8) were inhibited completely. In cells expressing I(TO2) (70% of total), DNP also suppressed an A9C-insensitive slow outward current by approximately 40%, but the holding current at -80 mV was unaffected. There was a approximately 2 min latency between inhibitory effects of DNP and subsequent membrane current increase, presumably caused by activation of the ATP-sensitive K+ channels (n = 16). We conclude that DNP acutely inhibits I(TO2) via a mechanism presumably separate from metabolic inhibition.

  4. Direct transparent electrode patterning on layered GaN substrate by screen printing of indium tin oxide nanoparticle ink for Eu-doped GaN red light-emitting diode

    SciTech Connect

    Kashiwagi, Y. Yamamoto, M.; Saitoh, M.; Takahashi, M.; Ohno, T.; Nakamoto, M.; Koizumi, A.; Fujiwara, Y.; Takemura, Y.; Murahashi, K.; Ohtsuka, K.; Furuta, S.

    2014-12-01

    Transparent electrodes were formed on Eu-doped GaN-based red-light-emitting diode (GaN:Eu LED) substrates by the screen printing of indium tin oxide nanoparticle (ITO np) inks as a wet process. The ITO nps with a mean diameter of 25 nm were synthesized by the controlled thermolysis of a mixture of indium complexes and tin complexes. After the direct screen printing of ITO np inks on GaN:Eu LED substrates and sintering at 850 °C for 10 min under atmospheric conditions, the resistivity of the ITO film was 5.2 mΩ cm. The fabricated LED up to 3 mm square surface emitted red light when the on-voltage was exceeded.

  5. KChIP2 genotype dependence of transient outward current (Ito) properties in cardiomyocytes isolated from male and female mice

    PubMed Central

    Waldschmidt, Lara; Junkereit, Vera; Bähring, Robert

    2017-01-01

    The transient outward current (Ito) in cardiomyocytes is largely mediated by Kv4 channels associated with Kv Channel Interacting Protein 2 (KChIP2). A knockout model has documented the critical role of KChIP2 in Ito expression. The present study was conducted to characterize in both sexes the dependence of Ito properties, including current magnitude, inactivation kinetics, recovery from inactivation and voltage dependence of inactivation, on the number of functional KChIP2 alleles. For this purpose we performed whole-cell patch-clamp experiments on isolated left ventricular cardiomyocytes from male and female mice which had different KChIP2 genotypes; i.e., wild-type (KChIP2+/+), heterozygous knockout (KChIP2+/-) or complete knockout of KChIP2 (KChIP2-/-). We found in both sexes a KChIP2 gene dosage effect (i.e., a proportionality between number of alleles and phenotype) on Ito magnitude, however, concerning other Ito properties, KChIP2+/- resembled KChIP2+/+. Only in the total absence of KChIP2 (KChIP2-/-) we observed a slowing of Ito kinetics, a slowing of recovery from inactivation and a negative shift of a portion of the voltage dependence of inactivation. In a minor fraction of KChIP2-/- myocytes Ito was completely lost. The distinct KChIP2 genotype dependences of Ito magnitude and inactivation kinetics, respectively, seen in cardiomyocytes were reproduced with two-electrode voltage-clamp experiments on Xenopus oocytes expressing Kv4.2 and different amounts of KChIP2. Our results corroborate the critical role of KChIP2 in controlling Ito properties. They demonstrate that the Kv4.2/KChIP2 interaction in cardiomyocytes is highly dynamic, with a clear KChIP2 gene dosage effect on Kv4 channel surface expression but not on inactivation gating. PMID:28141821

  6. Influence of Different Sol-gel Spin Coating Speed on Memristive Behaviour of Pt/TiO2/ZnO/ITO Device

    NASA Astrophysics Data System (ADS)

    Kasim, S. M. M.; Shaari, N. A. A.; Bakar, R. A.; Aznilinda, Z.; Mohamad, Zulfakri; Herman, S. H.

    2015-11-01

    Composite titanium dioxide (TiO2) and zinc oxide (ZnO) thin films were deposited on indium tin oxide (ITO) substrates using sol-gel spin coating technique. The electrical and physical characterizations of three different sol-gel spin coating speed were investigated using two-probe current-voltage (I-V) measurement, field emission scanning electron microscopy (FESEM) and surface profiler (SP) respectively. The I-V measurement results showed the pinched hysteresis loop for every single of devices thus indicate that all the devices are memristive. ROFF/RON ratio which was defined from the hysteresis loop of device with higher spin speed was slightly higher compared to others.

  7. High efficiency bifacial Cu2ZnSnSe4 thin-film solar cells on transparent conducting oxide glass substrates

    NASA Astrophysics Data System (ADS)

    Kim, Jung-Sik; Kang, Jin-Kyu; Hwang, Dae-Kue

    2016-09-01

    In this work, transparent conducting oxides (TCOs) have been employed as a back contact instead of Mo on Cu2ZnSnSe4 (CZTSe) thin-film solar cells in order to examine the feasibility of bifacial Cu2ZnSn(S,Se)4 (CZTSSe) solar cells based on a vacuum process. It is found that the interfacial reaction between flourine doped tin oxide (FTO) or indium tin oxide (ITO) and the CZTSe precursor is at odds with the conventional CZTSe/Mo reaction. While there is no interfacial reaction on CZTSe/FTO, indium in CZTSe/ITO was significantly diffused into the CZTSe layers; consequently, a SnO2 layer was formed on the ITO substrate. Under bifacial illumination, we achieved a power efficiency of 6.05% and 4.31% for CZTSe/FTO and CZTSe/ITO, respectively.

  8. Effects of Melatonin on Differentiation Potential of Ito Cells in Mice with Induced Fibrosis of the Liver.

    PubMed

    Nalobin, D S; Suprunenko, E A; Golichenkov, V A

    2016-10-01

    We studied the effects of melatonin on differentiation potential of Ito cells during atypical regeneration of mouse liver under conditions of CCl4-induced fibrosis. The dynamics of fibrosis was traced at the histological level and the effects of melatonin on the differentiation potential of mouse Ito cells were evaluated. Melatonin alleviated fibrotic changes in the liver tissue and reduced differentiation of Ito cells into myofibroblasts under conditions of atypical regeneration of the liver in induced fibrosis. The hepatoprotective role of melatonin was shown.

  9. Zero curvature representation, bi-Hamiltonian structure, and an integrable hierarchy for the Zakharov-Ito system

    NASA Astrophysics Data System (ADS)

    Baxter, Mathew; Choudhury, S. Roy; Van Gorder, Robert A.

    2015-06-01

    In the present paper, we present an integrable hierarchy for the Zakharov-Ito system. We first construct the Lenard recursion sequence and zero curvature representation for the Zakharov-Ito system, following Cao's method as significantly generalized by other authors. We then construct the bi-Hamiltonian structures employing variational trace identities but woven together with the Lenard recursion sequences. From this, we are in a position to construct an integrable hierarchy of equations from the Zakharov-Ito system, and we obtain the recursion operator and Poisson brackets for constructing this hierarchy. Finally, we demonstrate that the obtained hierarchy is indeed Liouville integrable.

  10. Electrochemical study of highly durable cathode with Pt supported on ITO-CNT composite for proton exchange membrane fuel cells

    SciTech Connect

    Park, Sehkyu; Shao, Yuyan; Viswanathan, Vilayanur V.; Liu, Jun; Wang, Yong

    2016-10-01

    In this paper, we describe a highly stable cathode containing a Pt catalyst supported on an indium tin oxide (ITO) and carbon nanotube (CNT) composite. The dependence of cathode performance and durability on the ITO content and the diameter of the CNTs were investigated by electrochemical techniques. The cathode with 30 wt% ITO and CNTs with diameters 10–20 nm in the composite offered preferred locations for Pt stabilization and was very resistant to carbon corrosion (i.e., 82.7% ESA retention and 105.7% mass activity retention after an accelerated stress test for 400 h).

  11. Optimization of ion-assisted ITO films by design of experiment

    NASA Astrophysics Data System (ADS)

    Schwyn Thöny, Silvia; Buchholz, Jürgen; Waldner, Stephan

    2011-09-01

    In this work we want to demonstrate how the methodology of Design of Experiment (DOE) can be used for the development of ion-assisted ITO films deposited at low temperatures. The optimization method allows us to identify the process parameters, which yield films with high transmittance and low resistivity. The article will show the results obtained for transmittance and resistivity. Furthermore, the dispersion of the refractive index and the extinction coefficient will be determined as well as the surface roughness. In ITO there is a trade-off between transmittance / absorbance and sheet resistance. Virtually absorption free films could be obtained with a resistivity of 3.2 μΩm, whereas the lowest resistivity (2.7 μΩm) yielded a transmittance, which was reduced by a few percent.

  12. Structural and morphological properties of ITO thin films grown by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Ghorannevis, Z.; Akbarnejad, E.; Ghoranneviss, M.

    2015-10-01

    Physical properties of transparent and conducting indium tin oxide (ITO) thin films grown by radiofrequency (RF) magnetron sputtering are studied systematically by changing deposition time. The X-ray diffraction (XRD) data indicate polycrystalline thin films with grain orientations predominantly along the (2 2 2) and (4 0 0) directions. From atomic force microscopy (AFM) it is found that by increasing the deposition time, the roughness of the film increases. Scanning electron microscopy (SEM) images show a network of a high-porosity interconnected nanoparticles, which approximately have a pore size ranging between 20 and 30 nm. Optical measurements suggest an average transmission of 80 % for the ITO films. Sheet resistances are investigated using four-point probes, which imply that by increasing the film thickness the resistivities of the films decrease to 2.43 × 10-5 Ω cm.

  13. AuNPs modified, disposable, ITO based biosensor: Early diagnosis of heat shock protein 70.

    PubMed

    Sonuç Karaboğa, Münteha Nur; Şimşek, Çiğdem Sayıklı; Sezgintürk, Mustafa Kemal

    2016-10-15

    This paper describes a novel, simple, and disposable immunosensor based on indium-tin oxide (ITO) sheets modified with gold nanoparticles to sensitively analyze heat shock protein 70 (HSP70), a potential biomarker that could be evaluated in diagnosis of some carcinomas. Disposable ITO coated Polyethylene terephthalate (PET) electrodes were used and modified with gold nanoparticles in order to construct the biosensors. Optimization and characterization steps were analyzed by electrochemical techniques such as electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Surface morphology of the biosensor was also identified by electrochemical methods, scanning electron microscopy (SEM), and atomic force microscopy (AFM). To interpret binding characterization of HSP70 to anti-HSP70 single frequency impedance method was successfully operated. Moreover, the proposed HSP70 immunosensor acquired good stability, repeatability, and reproducibility. Ultimately, proposed biosensor was introduced to real human serum samples to determine HSP70 sensitively and accurately.

  14. A very dark-and-conductive electrode based on Mo/MoOx/ITO structure

    NASA Astrophysics Data System (ADS)

    Feng, Yuanxiang; Chen, Shuming

    2016-10-01

    A dark and conductive electrode based on Mo/MoOx/ITO structure with low resistivity of 1.93 × 10-4 Ω/cm was fabricated by magnetron sputtering. The demonstrated dark electrode exhibits a low reflectance of 2.4-12.9% within the visible spectral range and average luminous reflectance of 3.3%. To improve the conductivity, pure Mo was first sputtered, followed by depositing a dark and conductive MoOx by introducing O2 flow during Mo sputtering. In order to further reduce the reflectance and set the lowest reflectance at the wavelength of 550 nm, which is most sensitive to human eyes, an ITO phase changing layer was introduced on top of the MoOx. The demonstrated dark and conductive electrode can serve as bottom contact and can potentially replace the circular polarizer for high contrast top-emitting organic light-emitting diodes.

  15. Interfacial behavior of resistive switching in ITO-PVK-Al WORM memory devices

    NASA Astrophysics Data System (ADS)

    Whitcher, T. J.; Woon, K. L.; Wong, W. S.; Chanlek, N.; Nakajima, H.; Saisopa, T.; Songsiriritthigul, P.

    2016-02-01

    Understanding the mechanism of resistive switching in a memory device is fundamental in order to improve device performance. The mechanism of current switching in a basic organic write-once read-many (WORM) memory device is investigated by determining the energy level alignments of indium tin oxide (ITO), poly(9-vinylcarbazole) (PVK) and aluminum (Al) using x-ray and ultraviolet photoelectron spectroscopy, current-voltage characterization and Auger depth profiling. The current switching mechanism was determined to be controlled by the interface between the ITO and the PVK. The electric field applied across the device causes the ITO from the uneven surface of the anode to form metallic filaments through the PVK, causing a shorting effect within the device leading to increased conduction. This was found to be independent of the PVK thickness, although the switch-on voltage was non-linearly dependent on the thickness. The formation of these filaments also caused the destruction of the interfacial dipole at the PVK-Al interface.

  16. Temperature sensor based on a hybrid ITO-silica resonant cavity

    PubMed Central

    Socorro, Abian B.; Soltani, Soheil; Del Villar, Ignacio; Corres, Jesus M.; Armani, Andrea M.

    2015-01-01

    Integrated optical devices comprised of multiple material systems are able to achieve unique performance characteristics, enabling applications in sensing and in telecommunications. Due to ease of fabrication, the majority of previous work has focused on polymer-dielectric or polymer-semiconductor systems. However, the environmental stability of polymers is limited. In the present work, a hybrid device comprised of an indium tin oxide (ITO) coating on a silicon dioxide toroidal resonant cavity is fabricated. Finite element method simulations of the optical field in the multi-material device are performed, and the optical mode profile is significantly altered by the high index film. The quality factor is also measured and is material loss limited. Additionally, its performance as a temperature sensor is characterized. Due to the high thermo-optic coefficient of ITO and the localization of the optical field in the ITO layer, the hybrid temperature sensor demonstrates a nearly 3-fold improvement in performance over the conventional silica device. PMID:25836065

  17. [Malignant transformation of a nevus of Ito: description of a rare case].

    PubMed

    Martínez-Peñuela, A; Iglesias, M E; Mercado, M R; Martínez-Peñuela, J M

    2011-12-01

    Dermal melanocytosis refers to congenital or acquired lesions characterized by the presence of dendritic cells derived from melanocytes that migrate from the neural crest to the epidermis. The nevus of Ito develops in the territory supplied by the acromioclavicular nerve. Malignant transformation in dermal melanocytosis is extremely rare, with only isolated case reports; only 2 cases of malignant transformation of a nevus of Ito have been reported. We report a very rare case that is the third to be described in the literature. The patient was a 24-year-old man who presented with a subcutaneous nodule that had developed in the anterolateral region of the thorax over the previous 8 months. The nodule was located beneath a faint blue-gray macule with poorly defined borders. Biopsy of the nodule revealed malignant melanoma; biopsies of the adjacent skin lesion showed a diffuse proliferation of scattered melanocytes in a collagen stroma in the reticular dermis. A diagnosis of malignant transformation of a nevus of Ito was made after other possibilities were ruled out.

  18. Nanosecond laser-induced damage of transparent conducting ITO film at 1064nm

    NASA Astrophysics Data System (ADS)

    Yoo, Jae-Hyuck; Adams, John J.; Menor, Marlon G.; Olson, Tammy Y.; Lee, Jonathan R. I.; Samanta, Amit; Bude, Jeff; Elhadj, Selim

    2016-12-01

    Transparent conducting films with superior laser damage performance have drawn intense interests toward optoelectronic applications under high energy density environment. In order to make optoelectronic applications with high laser damage performance, a fundamental understanding of damage mechanisms of conducting films is crucial. In this study, we performed laser damage experiments on tin-doped indium oxide films (ITO, Bandgap = 4.0 eV) using a nanosecond (ns) pulse laser (1064 nm) and investigated the underlying physical damage mechanisms. Single ns laser pulse irradiation on ITO films resulted in common thermal degradation features such as melting and evaporation although the laser photon energy (1.03 eV, 1064 nm) was smaller than the bandgap. Dominant laser energy absorption of the ITO film is attributed to free carriers due to degenerate doping. Upon multi-pulse irradiation on the film, damage initiation and growth were observed at lower laser influences, where no apparent damage was formed upon single pulse, suggesting a laser-induced incubation effect.

  19. Free-carrier electro-refraction modulation based on a silicon slot waveguide with ITO.

    PubMed

    Baek, Junsu; You, Jong-Bum; Yu, Kyoungsik

    2015-06-15

    Recently, silicon-waveguide-based hybrid modulators with high-performance electro-optic materials have been proposed to overcome the intrinsic limitations of silicon materials. Indium-tin-oxide (ITO) is one of the important candidates for such applications due to its unique features including the ENZ effect and electrically tunable permittivity. In this paper, we propose an ultra-compact integrated phase modulator which consists of a silicon slot waveguide with a thin ITO film in the slot region. In the near-infrared regime, bias-voltage-dependent free-carrier accumulation at the dielectric-ITO interface induces an epsilon-near-zero (ENZ) effect, and contributes to the strong phase modulation of the guided electromagnetic wave. With a voltage swing of 2 V, the device experiences a large variation of the effective modal index, resulting in a π radian phase shift within the device length of <5 μm at 210 THz according to our computer simulations. A high modulation efficiency of V(π)L(π)~0.0071 V·cm and a large device bandwidth of ~70 GHz suggest a potential for an ultra-compact optoelectronic component in the integrated silicon photonics platform.

  20. Soft chemistry based sponge-like indium tin oxide (ITO) — a prospective component of photoanode for solar cell application

    NASA Astrophysics Data System (ADS)

    Biswas, Prasanta Kumar; Das, Nilanjana

    2015-04-01

    Previously we reported the synthesis of novel organic-inorganic composite indium tin oxide (ITO) foam precursor leading to the formation of "sponge-like" ITO by burning away the organics. This newly made sponge-like ITO possesses relatively high electrical conductivity due to phonon confinement with reasonable pore structure and may have potential application as functional materials in semiconducting dye absorbing layer in dye-sensitized solar cell (DSSC) and also as the receptor of electrons injected from the quantum dots (QDs) of organic-inorganic hybrid QD based solar cell. This report is a short review of "sponge-like" ITO described as a lecture note on its future use as an alternative new prospective material for photoanode of solar cell in the domain of sustainable energy.

  1. Electrodeposition of CoS on ITO substrates for the counter electrode of dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Masuda, Tamiko; Anwar, Hafeez; Hill, Ian

    2012-10-01

    Dye-sensitized solar cells (DSSCs) provide a relatively low-cost option for harvesting solar energy. The counter electrode (CE) of a DSSC incorporates a catalyst layer, which plays a vital role in the cell cycle by reducing the triiodide ions in the electrolyte. In this study, CoS is studied as a possible replacement for platinum, the standard catalyst [1]. This is relevant because replacing Pt with CoS would reduce production barriers that are associated with cost and supply. Using a two-electrode ``dummy'' flow cell setup the effects of delay times, scan rates and bias voltages in electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements were studied. Preliminary results on CoS samples are taken and indicate charge transfer resistance values an order of magnitude higher than the Pt reference. Future steps to improve the CoS deposition process to optimize charge transfer will be discussed.[4pt] [1] Wang, M.; Anghel, A.M.; Marsan, B.; Ha, N.C.; Pootrakulchote, N.; Zakeeruddin, S.M.; Graetzel, M. J. Am. Chem. Soc. 2009, 131, 15976.

  2. Toward Plastic Smart Windows: Optimization of Indium Tin Oxide Electrodes for the Synthesis of Electrochromic Devices on Polycarbonate Substrates.

    PubMed

    Laurenti, Marco; Bianco, Stefano; Castellino, Micaela; Garino, Nadia; Virga, Alessandro; Pirri, Candido F; Mandracci, Pietro

    2016-03-01

    Plastic smart windows are becoming one of the key elements in view of the fabrication of inexpensive, lightweight electrochromic (EC) devices to be integrated in the new generation of high-energy-efficiency buildings and automotive applications. However, fabricating electrochromic devices on polymer substrates requires a reduction of process temperature, so in this work we focus on the development of a completely room-temperature deposition process aimed at the preparation of ITO-coated polycarbonate (PC) structures acting as transparent and conductive plastic supports. Without providing any substrate heating or surface activation pretreatments of the polymer, different deposition conditions are used for growing indium tin oxide (ITO) thin films by the radiofrequency magnetron sputtering technique. According to the characterization results, the set of optimal deposition parameters is selected to deposit ITO electrodes having high optical transmittance in the visible range (∼90%) together with low sheet resistance (∼8 ohm/sq). The as-prepared ITO/PC structures are then successfully tested as conductive supports for the fabrication of plastic smart windows. To this purpose, tungsten trioxide thin films are deposited by the reactive sputtering technique on the ITO/PC structures, and the resulting single electrode EC devices are characterized by chronoamperometric experiments and cyclic voltammetry. The fast switching response between colored and bleached states, together with the stability and reversibility of their electrochromic behavior after several cycling tests, are considered to be representative of the high quality of the EC film but especially of the ITO electrode. Indeed, even if no adhesion promoters, additional surface activation pretreatments, or substrate heating were used to promote the mechanical adhesion among the electrode and the PC surface, the observed EC response confirmed that the developed materials can be successfully employed for the

  3. High voltage and efficient bilayer heterojunction solar cells based on an organic-inorganic hybrid perovskite absorber with a low-cost flexible substrate.

    PubMed

    Chiang, Yi-Fang; Jeng, Jun-Yuan; Lee, Mu-Huan; Peng, Shin-Rung; Chen, Peter; Guo, Tzung-Fang; Wen, Ten-Chin; Hsu, Yao-Jane; Hsu, Ching-Ming

    2014-04-07

    A low temperature (<100 °C), flexible solar cell based on an organic-inorganic hybrid CH3NH3PbI3 perovskite-fullerene planar heterojunction (PHJ) is successfully demonstrated. In this manuscript, we study the effects of energy level offset between a solar absorber (organic-inorganic hybrid CH3NH3PbI3 perovskite) and the selective contact materials on the photovoltaic behaviors of the planar organometallic perovskite-fullerene heterojunction solar cells. We find that the difference between the highest occupied molecular orbital (HOMO) level of CH3NH3PbI3 perovskite and the Fermi level of indium-tin-oxide (ITO) dominates the voltage output of the device. ITO films on glass or on the polyethylene terephthalate (PET) flexible substrate with different work functions are investigated to illustrate this phenomenon. The higher work function of the PET/ITO substrate decreases the energy loss of hole transfer from the HOMO of perovskite to ITO and minimizes the energy redundancy of the photovoltage output. The devices using the high work function ITO substrate as contact material show significant open-circuit voltage enhancement (920 mV), with the power conversion efficiency of 4.54%, and these types of extra-thin planar bilayer heterojunction solar cells have the potential advantages of low-cost and lightweight.

  4. The investigation of electrodeposited Cu2O/ITO layers by chronocoulometry process: effect of electrical potential

    NASA Astrophysics Data System (ADS)

    Mohra, D.; Benhaliliba, M.; Serin, M.; Khelladi, M. R.; Lahmar, H.; Azizi, A.

    2016-10-01

    The thin films of Cu2O are deposited by electrodeposition technique onto indium tin oxide (ITO)-coated glass substrate at different potentials. The precursor is an aqueous solution which contains respectively 0.05 M of CuSO4 and citric acid at kept temperature of 60 °C and the applied potential varies within the {-0.4 V, -0.7 V} SCE range. Based on the chronocoulometry (CC) process, the electrochemical, structural and optical parameters are determined. We measured the current as function of potential within the {-0.4 V, -0.7 V} range and the higher current is found to be within the {-0.7V, -0.3 V} band. The grain sizes are of 12.12 nm and 35.47 nm according to (110) and (221) orientations respectively. The hightextural coefficient of 0.943 is recorded for the potential -0.7 V The transmittance of 72.25 %, within the visible band, is obtained for the as-grown layer at -0.4 V and the band gap is found to be 2.2 eV for the electrodeposition potential of -0.7 V Project supported the PNR (Nos. 8/U311/R77, U311/R81), the “Agencethematique de rechercheen science ettechnologie” (ATRST), the National Administration of Scientific Research, the CNEPRU of Oran University of Sciences and Technology (No. B00L02UN310220130011), and the Scientific Research Projects Coordination (Nos. 2012-01-01-KAP05, 2012-01-01-KAP06) Yildiz Technical University.

  5. Cleavage of denatured natural collagen type II by neutrophil gelatinase B reveals enzyme specificity, post-translational modifications in the substrate, and the formation of remnant epitopes in rheumatoid arthritis.

    PubMed

    Van den Steen, Philippe E; Proost, Paul; Grillet, Bernard; Brand, David D; Kang, Andrew H; Van Damme, Jo; Opdenakker, Ghislain

    2002-03-01

    During acute inflammation, leukocytes release proteolytic enzymes including matrix metalloproteinases (MMPs), but the physiopathological mechanisms and consequences of this process are not yet fully understood. Neutrophils, the predominant leukocyte type, produce neutrophil collagenase (MMP-8) and gelatinase B (MMP-9) but not the tissue inhibitors of MMPs. After stimulation, these cells also activate MMPs chemically. In arthritic diseases, neutrophils undergo great chemoattraction to the synovium, are activated by interleukin-8, and are stimulated to release gelatinase B in vivo. Production levels and net activities of gelatinase B were found to be absent in degenerative osteoarthritis but significantly increased in rheumatoid arthritis. The cleavage sites in cartilage type II collagen by gelatinase B were determined by a combination of reverse phase high-performance liquid chromatography, Edman degradation, and mass spectrometry analysis. The analysis revealed the site specificity of proline and lysine hydroxylations and O-linked glycosylation, the cleavage specificities by gelatinase B, and the preferential absence and presence of post-translational modifications at P2' and P5', respectively. Furthermore, gelatinase B leaves the immunodominant peptides intact, which are known from studies with (autoreactive) T cells. Lysine hydroxylation was detected at a critical position for T-cell activation. These data lend support to the thesis that extracellular proteolysis and other post-translational modifications of antigenic peptides may be critical in the establishment and perpetuation of autoimmune processes.

  6. Formation of substrate-based gold nanocage chains through dealloying with nitric acid

    PubMed Central

    Yan, Ziren; Wu, Ying

    2015-01-01

    Summary Metal nanocages have raised great interest because of their new properties and wide applications. Here, we report on the use of galvanic replacement reactions to synthesize substrate-supported Ag–Au nanocages from silver templates electrodeposited on transparent indium tin oxide (ITO) film coated glass. The residual Ag in the composition was dealloyed with 10% nitric acid. It was found that chains of Au nanocages were formed on the substrate surface during dealloying. When the concentration of HNO3 increased to 20%, the structures of nanocages were damaged and formed crescent or semi-circular shapes. The transfer process on the substrate surface was discussed. PMID:26199839

  7. Influence of sputtering power on the optical properties of ITO thin films

    SciTech Connect

    K, Aijo John; M, Deepak T, Manju; Kumar, Vineetha V.

    2014-10-15

    Tin doped indium oxide films are widely used in transparent conducting coatings such as flat panel displays, crystal displays and in optical devices such as solar cells and organic light emitting diodes due to the high electrical resistivity and optical transparency in the visible region of solar spectrum. The deposition parameters have a commendable influence on the optical and electrical properties of the thin films. In this study, ITO thin films were prepared by RF magnetron sputtering. The properties of the films prepared under varying sputtering power were compared using UV- visible spectrophotometry. Effect of sputtering power on the energy band gap, absorption coefficient and refractive index are investigated.

  8. Core-shell ITO/ZnO/CdS/CdTe nanowire solar cells

    NASA Astrophysics Data System (ADS)

    Williams, B. L.; Taylor, A. A.; Mendis, B. G.; Phillips, L.; Bowen, L.; Major, J. D.; Durose, K.

    2014-02-01

    Radial p-n junction nanowire (NW) solar cells with high densities of CdTe NWs coated with indium tin oxide (ITO)/ZnO/CdS triple shells were grown with excellent heterointerfaces. The optical reflectance of the devices was lower than for equivalent planar films by a factor of 100. The best efficiency for the NW solar cells was η = 2.49%, with current transport being dominated by recombination, and the conversion efficiencies being limited by a back contact barrier (ϕB = 0.52 eV) and low shunt resistances (RSH < 500 Ω.cm2).

  9. Hypomelanosis of Ito and X;autosome translocations: a unifying hypothesis.

    PubMed Central

    Hatchwell, E

    1996-01-01

    Hypomelanosis of Ito is a sporadic multisystem disorder known to be associated in many cases with chromosomal mosaicism. While no particular pattern is generally evident for the specific chromosomes involved in such patients, a subgroup of female patients exists in whom the common factor is the presence of a balanced, constitutional X;autosome translocation, with a cytogenetic breakpoint in the pericentromeric region of the X. It is argued here that the phenotype in these cases results not from the interruption of X linked genes but from the presence of mosaic functional disomy of X sequences above the breakpoint. Images PMID:8728687

  10. Photovoltaic performance of hybrid ITO/PEDOT:PSS/n-SnS/Al solar cell structure

    NASA Astrophysics Data System (ADS)

    Jain, Priyal; Arun, P.

    2016-07-01

    The present paper discusses the performance of ITO/PEDOT:PSS/n-SnS/Al structured solar cells fabricated by thermal evaporation. The performance characterizing parameters such as the open circuit voltage, short circuit current density, series resistance, parallel resistance, ideality factor and the overall efficiency were found to be dependent on the SnS grain size in the nano-meter regime and incident light intensity. The experimental work directly reconfirms the theoretical results and ideas raised in the literature by early researchers.

  11. Fabrication of nanostructured transmissive optical devices on ITO-glass with UV1116 photoresist using high-energy electron beam lithography

    NASA Astrophysics Data System (ADS)

    Williams, Calum; Bartholomew, Richard; Rughoobur, Girish; Gordon, George S. D.; Flewitt, Andrew J.; Wilkinson, Timothy D.

    2016-12-01

    High-energy electron beam lithography for patterning nanostructures on insulating substrates can be challenging. For high resolution, conventional resists require large exposure doses and for reasonable throughput, using typical beam currents leads to charge dissipation problems. Here, we use UV1116 photoresist (Dow Chemical Company), designed for photolithographic technologies, with a relatively low area dose at a standard operating current (80 kV, 40-50 μC cm-2, 1 nAs-1) to pattern over large areas on commercially coated ITO-glass cover slips. The minimum linewidth fabricated was ˜33 nm with 80 nm spacing; for isolated structures, ˜45 nm structural width with 50 nm separation. Due to the low beam dose, and nA current, throughput is high. This work highlights the use of UV1116 photoresist as an alternative to conventional e-beam resists on insulating substrates. To evaluate suitability, we fabricate a range of transmissive optical devices, that could find application for customized wire-grid polarisers and spectral filters for imaging, which operate based on the excitation of surface plasmon polaritons in nanosized geometries, with arrays encompassing areas ˜0.25 cm2.

  12. Fabrication of nanostructured transmissive optical devices on ITO-glass with UV1116 photoresist using high-energy electron beam lithography.

    PubMed

    Williams, Calum; Bartholomew, Richard; Rughoobur, Girish; Gordon, George S D; Flewitt, Andrew J; Wilkinson, Timothy D

    2016-12-02

    High-energy electron beam lithography for patterning nanostructures on insulating substrates can be challenging. For high resolution, conventional resists require large exposure doses and for reasonable throughput, using typical beam currents leads to charge dissipation problems. Here, we use UV1116 photoresist (Dow Chemical Company), designed for photolithographic technologies, with a relatively low area dose at a standard operating current (80 kV, 40-50 μC cm(-2), 1 nAs(-1)) to pattern over large areas on commercially coated ITO-glass cover slips. The minimum linewidth fabricated was ∼33 nm with 80 nm spacing; for isolated structures, ∼45 nm structural width with 50 nm separation. Due to the low beam dose, and nA current, throughput is high. This work highlights the use of UV1116 photoresist as an alternative to conventional e-beam resists on insulating substrates. To evaluate suitability, we fabricate a range of transmissive optical devices, that could find application for customized wire-grid polarisers and spectral filters for imaging, which operate based on the excitation of surface plasmon polaritons in nanosized geometries, with arrays encompassing areas ∼0.25 cm(2).

  13. The utilization of SiNWs/AuNPs-modified indium tin oxide (ITO) in fabrication of electrochemical DNA sensor.

    PubMed

    Rashid, Jahwarhar Izuan Abdul; Yusof, Nor Azah; Abdullah, Jaafar; Hashim, Uda; Hajian, Reza

    2014-12-01

    This work describes the incorporation of SiNWs/AuNPs composite as a sensing material for DNA detection on indium tin-oxide (ITO) coated glass slide. The morphology of SiNWs/AuNPs composite as the modifier layer on ITO was studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The morphological studies clearly showed that SiNWs were successfully decorated with 20 nm-AuNPs using self-assembly monolayer (SAM) technique. The effective surface area for SiNWs/AuNPs-modified ITO enhanced about 10 times compared with bare ITO electrode. SiNWs/AuNPs nanocomposite was further explored as a matrix for DNA probe immobilization in detection of dengue virus as a bio-sensing model to evaluate its performance in electrochemical sensors. The hybridization of complementary DNA was monitored by differential pulse voltammetry (DPV) using methylene blue (MB) as the redox indicator. The fabricated biosensor was able to discriminate significantly complementary, non-complementary and single-base mismatch oligonucleotides. The electrochemical biosensor was sensitive to target DNA related to dengue virus in the range of 9.0-178.0 ng/ml with detection limit of 3.5 ng/ml. In addition, SiNWs/AuNPs-modified ITO, regenerated up to 8 times and its stability was up to 10 weeks at 4°C in silica gel.

  14. Optical and electrochemical properties of ordered macroporous gold array on the ITO surface

    NASA Astrophysics Data System (ADS)

    Lu, Huidan; Liu, Yongping; Han, Guo-Cheng

    2011-06-01

    The electrochemical and optical properties of transparent, two-dimensional macroporous gold film were investigated. Colloidal crystal templates were assembled onto indium-doped tin oxide (ITO) glass surface through vertical depositing method. Following gold electrodeposition, they were removed by dissolution with tetrahydrofuran (THF). The highly ordered macroporous gold array was achieved. It was characterized by scanning electron microscope (SEM) and ultraviolet visible (UV-vis) spectrophotometry. The optical transparency of the gold film was near 25% and fairly constant between 300 and 900 nm. The macroporous gold film electrode was mounted into a thin-layer transmission cell. The electrochemical response was evaluated by thin-layer cyclic voltammograms (CV) of the Fe (CN) 63-/Fe (CN) 64- couple. Thin-layer cell exhibits good shape of waves and nearly symmetric cathodic and anodic waves. E0' value and n of TMPD + rad /TMPD (TMPD is acronyms for N,N,N',N'-tetramethyl-p-phenylenediamine, and TMPD + rad is its mono-cation radical) couple were determined. Furthermore, results demonstrated electrolytic equilibrium was faster reached in macroporous gold film than ITO electrode.

  15. Flexible, transparent and high-power triboelectric generator with asymmetric graphene/ITO electrodes.

    PubMed

    Song, Xinbo; Chen, Yuanfu; Li, Pingjian; Liu, Jingbo; Qi, Fei; Zheng, Binjie; Zhou, Jinhao; Hao, Xin; Zhang, Wanli

    2016-07-29

    The reported flexible and transparent triboelectric generator (FTTG) can only output ultralow power density (∼2 μW cm(-2)), which has seriously hindered its further development and application. The low power density of FTTG is mainly limited by the transparent material and the electrode structure. Herein, for the first time, a FTTG with a superior power density of 60.7 μW cm(-2) has been fabricated by designing asymmetric electrodes where graphene and indium tin oxide (ITO) act as top and bottom electrodes respectively. Moreover, the performance of FTTG with graphene/ITO (G/I) asymmetric electrodes (GI-FTTG) almost remains unchanged even after 700 cycles, indicating excellent mechanical stability. The excellent performance of GI-FTTG can be attributed to the suitable materials and unique asymmetric electrode structure: the extraordinary flexibility of the graphene top electrode ensures the GI-FTTG excellent mechanical robustness and stability even after longer cycles, and the bottom electrode with very low sheet resistance guarantees lower internal resistance and higher production rate of induction charges to obtain higher output power density. It shows that light-emitting diodes (LED) can be easily powered by GI-FTTG, which demonstrates that the GI-FTTG is very promising for harvesting electrical energy from human activities by using flexible and transparent devices.

  16. Flexible, transparent and high-power triboelectric generator with asymmetric graphene/ITO electrodes

    NASA Astrophysics Data System (ADS)

    Song, Xinbo; Chen, Yuanfu; Li, Pingjian; Liu, Jingbo; Qi, Fei; Zheng, Binjie; Zhou, Jinhao; Hao, Xin; Zhang, Wanli

    2016-07-01

    The reported flexible and transparent triboelectric generator (FTTG) can only output ultralow power density (˜2 μW cm-2), which has seriously hindered its further development and application. The low power density of FTTG is mainly limited by the transparent material and the electrode structure. Herein, for the first time, a FTTG with a superior power density of 60.7 μW cm-2 has been fabricated by designing asymmetric electrodes where graphene and indium tin oxide (ITO) act as top and bottom electrodes respectively. Moreover, the performance of FTTG with graphene/ITO (G/I) asymmetric electrodes (GI-FTTG) almost remains unchanged even after 700 cycles, indicating excellent mechanical stability. The excellent performance of GI-FTTG can be attributed to the suitable materials and unique asymmetric electrode structure: the extraordinary flexibility of the graphene top electrode ensures the GI-FTTG excellent mechanical robustness and stability even after longer cycles, and the bottom electrode with very low sheet resistance guarantees lower internal resistance and higher production rate of induction charges to obtain higher output power density. It shows that light-emitting diodes (LED) can be easily powered by GI-FTTG, which demonstrates that the GI-FTTG is very promising for harvesting electrical energy from human activities by using flexible and transparent devices.

  17. Development of an amperometric sulfite biosensor based on SO(x)/PBNPs/PPY modified ITO electrode.

    PubMed

    Rawal, Rachna; Pundir, C S

    2012-11-01

    A sulfite oxidase (SO(x)) (EC 1.8.3.1) purified from Syzygium cumini leaves was immobilized onto prussian blue nanoparticles/polypyrrole composite (PBNPs/PPY) electrodeposited onto the surface of indium tin oxide (ITO) electrode. An amperometric sulfite biosensor was fabricated using SO(x)/PBNPs/PPY/ITO electrode as working electrode, Ag/AgCl as standard and Pt wire as auxiliary electrode connected through a potentiostat. The working electrode was characterized by Fourier transform infrared (FTIR) spectroscopy, cyclic voltammetry (CV), scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS) before and after immobilization of SO(x). The biosensor showed optimum response within 2s, when operated at 20 mV s⁻¹ in 0.1M Tris-HCl buffer, pH 8.5 and at 35 °C. Linear range and minimum detection limit were 0.5-1000 μM and 0.12 μM (S/N=3) respectively. There was good correlation (r=0.99) between red wine samples sulfite value by standard DTNB method and the present method. The sensor was evaluated with 97% recovery of added sulfite in red wine samples and 2.2% and 4.3% within and between batch coefficients of variation respectively. The sensor was employed for determination of sulfite level in red and white wine samples. The enzyme electrode was used 200 times over a period of 3 months when stored at 4 °C.

  18. Respirable Indium Exposures, Plasma Indium, and Respiratory Health Among Indium-Tin Oxide (ITO) Workers

    PubMed Central

    Cummings, Kristin J.; Virji, M. Abbas; Park, Ji Young; Stanton, Marcia L.; Edwards, Nicole T.; Trapnell, Bruce C.; Carey, Brenna; Stefaniak, Aleksandr B.; Kreiss, Kathleen

    2016-01-01

    Background Workers manufacturing indium-tin oxide (ITO) are at risk of elevated indium concentration in blood and indium lung disease, but relationships between respirable indium exposures and biomarkers of exposure and disease are unknown. Methods For 87 (93%) current ITO workers, we determined correlations between respirable and plasma indium and evaluated associations between exposures and health outcomes. Results Current respirable indium exposure ranged from 0.4 to 108 μg/m3 and cumulative respirable indium exposure from 0.4 to 923 μg-yr/m3. Plasma indium better correlated with cumulative (rs = 0.77) than current exposure (rs = 0.54) overall and with tenure ≥1.9 years. Higher cumulative respirable indium exposures were associated with more dyspnea, lower spirometric parameters, and higher serum biomarkers of lung disease (KL-6 and SP-D), with significant effects starting at 22 μg-yr/m3, reached by 46% of participants. Conclusions Plasma indium concentration reflected cumulative respirable indium exposure, which was associated with clinical, functional, and serum biomarkers of lung disease. PMID:27219296

  19. Optical properties of local surface plasmon resonance in Ag/ITO sliced nanosphere by the discrete dipole approximation

    NASA Astrophysics Data System (ADS)

    Haiwei, Mu; Jingwei, Lv; Zhaoting, Liu; Shijie, Zheng; Lin, Yang; Tao, Sun; Qiang, Liu; Chao, Liu

    2016-04-01

    Optical properties of localized surface plasmon resonances (LSPR) of Ag/ITO sliced nanosphere have been studied using discrete dipole approximation and plasmon hybridization theory. It is found that different morphologies of sliced nanosphere can induce distinctive features in the extinction spectra. In the meanwhile, gap distances and refractive index of the surrounding medium could modulate the plasmon hybridization and the LSPR shifting. At large separation, the shift of LSPR peaks for the nanosphere sliced in halves consisting of ITO and Ag is small and insensitive to the gap distance in the weak coupling, whereas smaller separation exhibits a distinct red shift. Additionally, multiple resonance peaks are excited for the nanosphere sliced in quarters consisting of ITO and Ag. In this situation, electric field is mainly distributed in the gap region of sliced nanosphere and the central point. These results indicate that different morphologies of sliced nanosphere could create abundant tunable LSPR modes, which provides potential for multiplex optical sensing.

  20. Modeling of sputtered and electron-beam evaporated multilayer ITO/InP solar cells based on efficiency studies

    NASA Astrophysics Data System (ADS)

    Henry, Jasmine; Livingstone, John

    2001-10-01

    With an energy gap of 1.34 eV, indium phosphide (InP) is an ideal material for solar energy conversion. Much work has been carried out on sputtered indium-tin-oxide (ITO)/InP solar cells but modeling of this structure has long been the subject of debate. The double-layer structure used in this work was originally devised to minimize the surface degradation of InP when exposed to normal heating steps during the fabrication process due to the low congruent temperature of InP. We deposited a thin protective layer of either ITO or indium-tin to protect the front surface of the InP before any heating stages took place. A second layer, ITO, was then deposited to compete the junction. Variation of film deposition conditions, thicknesses and annealing steps worked to improve device performances as well as provide insight into junction mechanisms.

  1. Embedding metal electrodes in thick active layers for ITO-free plasmonic organic solar cells with improved performance.

    PubMed

    Lee, Sangjun; Mason, Daniel R; In, Sungjun; Park, Namkyoo

    2014-06-30

    We propose and numerically investigate the optical performance of a novel plasmonic organic solar cell with metallic nanowire electrodes embedded within the active layer. A significant improvement (~15%) in optical absorption over both a conventional ITO organic solar cell and a conventional plasmonic organic solar cell with top-loaded metallic grating is predicted in the proposed structure. Optimal positioning of the embedded metal electrodes (EME) is shown to preserve the condition for their strong plasmonic coupling with the metallic back-plane, meanwhile halving the hole path length to the anode which allows for a thicker active layer that increases the optical path length of propagating modes. With a smaller sheet resistance than a typical 100 nm thick ITO film transparent electrode, and an increased optical absorption and hole collection efficiency, our EME scheme could be an excellent alternative to ITO organic solar cells.

  2. Surface modification by molecular ions

    SciTech Connect

    Hanley, L.; Schultz, D. G.; Ada, E. T.

    1999-06-10

    There are several advantages in using molecular ions for surface modification. The modification can be confined to the uppermost layer of the surface, the molecular character of the ion can be imparted to the surface, and sputter yields are often higher. These effects are demonstrated by the use of mass selected ion beams incident on well characterized surfaces. Energy transfer is examined by detecting the masses and energies of ions scattered off surfaces and performing molecular dynamics simulations. Surface modification is followed by chemical analysis with x-ray photoelectron spectroscopy and surface mass spectrometry. TRIDYN monte carlo simulations are used to support some of the modification experiments. Energy transfer is examined for Si(CD{sub 3}){sub 3}{sup +} scattered off clean and hexanethiolate covered Au(111). Adsorbate desorption cross sections and substrate damage depths for NH{sub 3}/CO/Ni(111) are compared for 10-1000 eV isobaric atomic and polyatomic ions, Xe{sup +} and SF{sub 5}{sup +}. The surface chemical modification of polystyrene thin films by 10-100 eV SF{sub 5}{sup +} and C{sub 3}F{sub 5}{sup +} ions is also examined.

  3. Laser modification of thermally sprayed coatings

    NASA Astrophysics Data System (ADS)

    Uglov, A. A.; Fomin, A. D.; Naumkin, A. O.; Pekshev, P. Iu.; Smurov, I. Iu.

    1987-08-01

    Experimental results are reported on the modification of thermally sprayed coatings on steels and aluminum alloys using pulsed YAG and CW CO2 lasers. In particular, results obtained for self-fluxing Ni9CrBSi powders, ZRO2 ceramic, and titanium are examined. It is shown that the laser treatment of thermally sprayed coatings significantly improves their physicomechanical properties; it also makes it possible to obtain refractory coatings on low-melting substrates with good coating-substrate adhesion.

  4. Combustion synthesized indium-tin-oxide (ITO) thin film for source/drain electrodes in all solution-processed oxide thin-film transistors

    NASA Astrophysics Data System (ADS)

    Tue, Phan Trong; Inoue, Satoshi; Takamura, Yuzuru; Shimoda, Tatsuya

    2016-06-01

    We report combustion solution synthesized (SCS) indium-tin-oxide (ITO) thin film, which is a well-known transparent conductive oxide, for source/drain (S/D) electrodes in solution-processed amorphous zirconium-indium-zinc-oxide TFT. A redox-based combustion synthetic approach is applied to ITO thin film using acetylacetone as a fuel and metal nitrate as oxidizer. The structural and electrical properties of SCS-ITO precursor solution and thin films were systematically investigated with changes in tin concentration, indium metal precursors, and annealing conditions such as temperature, time, and ambient. It was found that at optimal conditions the SCS-ITO thin film exhibited high crystalline quality, atomically smooth surface (RMS ~ 4.1 Å), and low electrical resistivity (4.2 × 10-4 Ω cm). The TFT using SCS-ITO film as the S/D electrodes showed excellent electrical properties with negligible hysteresis. The obtained "on/off" current ratio, subthreshold swing factor, subthreshold voltage, and field-effect mobility were 5 × 107, 0.43 V/decade, 0.7 V, and 2.1 cm2/V s, respectively. The performance and stability of the SCS-ITO TFT are comparable to those of the sputtered-ITO TFT, emphasizing that the SCS-ITO film is a promising candidate for totally solution-processed oxide TFTs.

  5. Interfacial Energy Alignment at the ITO/Ultra-Thin Electron Selective Dielectric Layer Interface and Its Effect on the Efficiency of Bulk-Heterojunction Organic Solar Cells.

    PubMed

    Itoh, Eiji; Goto, Yoshinori; Saka, Yusuke; Fukuda, Katsutoshi

    2016-04-01

    We have investigated the photovoltaic properties of an inverted bulk heterojunction (BHJ) cell in a device with an indium-tin-oxide (ITO)/electron selective layer (ESL)/P3HT:PCBM active layer/MoOx/Ag multilayered structure. The insertion of only single layer of poly(diallyl-dimethyl-ammonium chloride) (PDDA) cationic polymer film (or poly(ethyleneimine) (PEI) polymeric interfacial dipole layer) and titanium oxide nanosheet (TN) films as an ESL effectively improved cell performance. Abnormal S-shaped curves were observed in the inverted BHJ cells owing to the contact resistance across the ITO/active layer interface and the ITO/PDDA/TN/active layer interface. The series resistance across the ITO/ESL interface in the inverted BHJ cell was successfully reduced using an interfacial layer with a positively charged surface potential with respect to ITO base electrode. The positive dipole in PEI and the electronic charge phenomena at the electrophoretic deposited TN (ED-TN) films on ITO contributed to the reduction of the contact resistance at the electrode interface. The surface potential measurement revealed that the energy alignment by the transfer of electronic charges from the ED-TN to the base electrodes. The insertion of the ESL with a large positive surface potential reduced the potential barrier for the electron injection at ITO/TN interface and it improved the photovoltaic properties of the inverted cell with an ITO/TN/active layer/MoOx/Ag structure.

  6. Core-shell ITO/ZnO/CdS/CdTe nanowire solar cells

    SciTech Connect

    Williams, B. L.; Phillips, L.; Major, J. D.; Durose, K.; Taylor, A. A.; Mendis, B. G.; Bowen, L.

    2014-02-03

    Radial p-n junction nanowire (NW) solar cells with high densities of CdTe NWs coated with indium tin oxide (ITO)/ZnO/CdS triple shells were grown with excellent heterointerfaces. The optical reflectance of the devices was lower than for equivalent planar films by a factor of 100. The best efficiency for the NW solar cells was η = 2.49%, with current transport being dominated by recombination, and the conversion efficiencies being limited by a back contact barrier (ϕ{sub B} = 0.52 eV) and low shunt resistances (R{sub SH} < 500 Ω·cm{sup 2})

  7. The neurologic aspects of hypomelanosis of Ito: Case report and review of the literature

    PubMed Central

    Hassan, Hamdy H; Hamad, Muddathir H A; Alhumidi, Ahmed

    2014-01-01

    The term hypomelanosis of Ito (HI) is applied to individuals with skin hypopigmentation along the lines of Blaschko. Although it was originally described as a purely cutaneous disease, subsequent studies describing HI reported a 33% to 94% association with multiple extracutaneous manifestations, mostly of the central nervous and musculoskeletal systems. This leads to characterization of HI as a neurocutaneous disorder. We report a 10-year-old boy who presented with constellation of multiple congenital anomalies including facial dysmorphism, skin hypopigmentation, musculoskeletal, and nervous system abnormalities. The latter manifested as hypotonia, generalized seizures, and mild mental retardation. Cranial magnetic resonance imaging revealed normal finding initially, however; follow-up diffusion weighted images were suggestive of a possible iron accumulation. The facial phenotype coupled with the bilateral globus pallidi lesions were never been reported in association with HI. Thus, our patient represents a possible novel example of HI. PMID:27493406

  8. Intense deep-blue electroluminescence from ITO/Y₂O₃/Ag structure.

    PubMed

    Yin, Xue; Wang, Shenwei; Li, Ling; Mu, Guangyao; Tang, Ying; Duan, Wubiao; Yi, Lixin

    2015-07-13

    ITO/Y₂O₃/Ag devices were fabricated using Y₂O₃ films as insulator. Four intense and sharp lines with half-peak width of 4 nm were observed for the 293.78 nm InI, 316.10 nm InI, 444.82 nm InII and 403.07 nm InIII transitions. Luminescence mechanism was illustrated by cross-section of the devices based on the analysis of surface morphology. Under the action of strong electric field, the loss of K-shell electrons led to the occurrence of characteristic radiation of indium ions. In addition, the device with turn-on voltage of 10V demonstrates typical I-V diode characteristics. Moreover, Y₂O₃/In₂O₃ multiple films as the insulation layer instead of single Y₂O₃ films was found to improve the device performance with excellent CIE (x, y) coordinates (0.16, 0.03).

  9. Calcium sensitizers isolated from the edible pine mushroom, Tricholoma matsutake (S. Ito & Imai) Sing.

    PubMed

    Hou, Yunlong; Sun, Shichao; Wu, Lijun; Wang, Xiaodan; Li, Ting; Zhang, Minyun; Wang, Jianwei; Wang, Libo

    2013-01-01

    Three lactam compounds were isolated from the fruiting body of Tricholoma matsutake (S. Ito & Imai) Sing., an edible mushroom, and their structures were identified as cyclo-S-proline-R-leucine (1), hexahydro-2H-azepin-2-one (2), and butyl 5-oxo-2-pyrrolidine carboxylate (3) by chemical, physicochemical, and spectral evidence. In in vitro screening tests, compounds 1 and 2 acted as calcium sensitizers in ventricular cells from rat. Further studies on compounds 1 and 2 in ex vivo isolated right atria showed positive inotropic effects without disturbing the spontaneous beating rate. The inotropic effect of compounds 1 and 2 could be greatly abolished by pretreating the myocardium in Ca(2+)-free solution. These findings indicate that compounds 1 and 2 can significantly increase the calcium ion concentration ([Ca2+]i) in myocytes, which is greatly dependent on the influx of extracellular Ca2+.

  10. Magneto-Seebeck effect in an ITO/PEDOT:PSS/Au thin-film device

    NASA Astrophysics Data System (ADS)

    Wang, Hongfeng; Liu, Qing; Tisdale, Jeremy; Xu, Ling; Liu, Yuchun; Hu, Bin

    2016-04-01

    This article reports giant magnetic field effects on the Seebeck coefficient by exerting a Lorentz force on charge diffusion based on vertical multi-layer ITO/PEDOT:PSS/Au thin-film devices. The Lorentz force, induced by an external magnetic field, changes the charge transport and consequently generates angular dependent magnetoresistance. The proposed mechanism of the magneto-Seebeck effect is proved by measuring the magnetoresistance at a parallel, 45o and perpendicular angle to the temperature gradient. The gradual change of the magnetoresistance from a parallel to perpendicular angle indicates that the Lorentz force is a key driving force to develop the magneto-Seebeck effect. Therefore, our experimental results demonstrate a magnetic approach to control the thermoelectric properties in organic materials.

  11. ITOS to EDGE "Bridge" Software for Morpheus Lunar/Martian Vehicle

    NASA Technical Reports Server (NTRS)

    Hirsh, Robert; Fuchs, Jordan

    2012-01-01

    My project Involved Improving upon existing software and writing new software for the Project Morpheus Team. Specifically, I created and updated Integrated Test and Operations Systems (ITOS) user Interfaces for on-board Interaction with the vehicle during archive playback as well as live streaming data. These Interfaces are an integral part of the testing and operations for the Morpheus vehicle providing any and all information from the vehicle to evaluate instruments and insure coherence and control of the vehicle during Morpheus missions. I also created a "bridge" program for Interfacing "live" telemetry data with the Engineering DOUG Graphics Engine (EDGE) software for a graphical (standalone or VR dome) view of live Morpheus nights or archive replays, providing graphical representation of vehicle night and movement during subsequent tests and in real missions.

  12. P-Cu2O/n-ZnO nanowires on ITO glass for solar cells.

    PubMed

    Zhang, Jin; Que, Wenxiu; Zhong, Peng; Zhu, Gangqiang

    2010-11-01

    In this paper, the fabrication and characterization of a heterojunction solar cell based on p-Cu2O/n-ZnO nanowires on ITO glass are presented. ZnO aligned nanocrystal seed layer is firstly prepared by RF magnetron sputtering technique, and then vertical ZnO nanowire arrays with an acicular crystal structure are obtained by using a chemical bath deposition processing. The results indicate that the ZnO nanowires with a diameter of about 50 nm and 500 nm in length can be easily obtained. The absorption and transmittance of the ZnO nanowires are studied. It is also noted that the Cu2O can fill well into the space between ZnO nanowires by an electrodeposition process. Furthermore, the effect of the Cu2O orientation on the cell performance is also presented.

  13. Photoelectric properties of ITO/CdS/chlorophyll a/Ag heterojunction solar cells

    SciTech Connect

    Segui, J.; Hotchandani, S.; Baddou, D.; Leblanc, R.M. )

    1991-10-31

    The heterojunction ITO/CdS/Chl a/Ag (Chl a = chlorophyll a) solar cells have been prepared by sequential electrodeposition of CdS and Chl a onto conductive indium-tin oxide (ITO) electrode followed by vacuum deposition of Ag, and their photovoltaic studies have been carried out. The dark J-V and photovoltaic characteristics, especially the action spectra, suggest the presence of a barrier at CdS/CFhl a interface. Various photovoltaic parameters of the cells obtained for the incident light power of 20 {mu}W/Cm{sup 2} at 740 nm, the maximum of Chl a absorption in red region, are as follows: J{sub SC} {approx equal} 150-200 nA/cm{sup 2}, V{sub OC} {approx} 0.35-0.40 V, ff = 0.26, and {eta} (%) = 0.17. The measurements performed at three wavelengths, namely, 740, 680, and 560 nm, indicate that the cells (illuminated through CdS electrode) perform better for weakly absorbed light at 560 nm. The results further show that the use of CdS instead of Al as rectifying electrode has definitely led to an improvement in the performance of CdS/Chl a over Al/Chl a cells in terms of the decreased internal resistances, decreased dark current and voltage, increased fill factors, and increased power conversion efficiencies. This has been attributed to the elimination of insulating layer of Al{sub 2}O{sub 3} existing at Al/Chl a interface.

  14. CdS nanoparticles sensitization of Al-doped ZnO nanorod array thin film with hydrogen treatment as an ITO/FTO-free photoanode for solar water splitting

    PubMed Central

    2012-01-01

    Aluminum-doped zinc oxide (AZO) nanorod array thin film with hydrogen treatment possesses the functions of transparent conducting oxide thin film and 1-D nanostructured semiconductor simultaneously. To enhance the absorption in the visible light region, it is sensitized by cadmium sulfide (CdS) nanoparticles which efficiently increase the absorption around 460 nm. The CdS nanoparticles-sensitized AZO nanorod array thin film with hydrogen treatment exhibits significantly improved photoelectrochemical property. After further heat treatment, a maximum short current density of 5.03 mA cm−2 is obtained under illumination. They not only are much higher than those without CdS nanoparticles sensitization and those without Al-doping and/or hydrogen treatment, but also comparable and even slightly superior to some earlier works for the CdS-sensitized zinc oxide nanorod array thin films with indium tin oxide (ITO) or fluorine-doped tin oxide (FTO) as substrates. This demonstrated successfully that the AZO nanorod array thin film with hydrogen treatment is quite suitable as an ITO/FTO-free photoanode and has great potentials in solar water splitting after sensitization by quantum dots capable of visible light absorption. PMID:23098050

  15. Size-controlled InGaN/GaN nanorod LEDs with an ITO/graphene transparent layer

    NASA Astrophysics Data System (ADS)

    Shim, Jae-Phil; Seong, Won-Seok; Min, Jung-Hong; Kong, Duk-Jo; Seo, Dong-Ju; Kim, Hyung-jun; Lee, Dong-Seon

    2016-11-01

    We introduce ITO on graphene as a current-spreading layer for separated InGaN/GaN nanorod LEDs for the purpose of passivation-free and high light-extraction efficiency. Transferred graphene on InGaN/GaN nanorods effectively blocks the diffusion of ITO atoms to nanorods, facilitating the production of transparent ITO/graphene contact on parallel-nanorod LEDs, without filling the air gaps, like a bridge structure. The ITO/graphene layer sufficiently spreads current in a lateral direction, resulting in uniform and reliable light emission observed from the whole area of the top surface. Using KOH treatment, we reduce series resistance and reverse leakage current in nanorod LEDs by recovering the plasma-damaged region. We also control the size of the nanorods by varying the KOH treatment time and observe strain relaxation via blueshift in electroluminescence. As a result, bridge-structured LEDs with 8 min of KOH treatment show 15 times higher light-emitting efficiency than with 2 min of KOH treatment.

  16. Spectroelectrochemistry of Fe(III)- and Co(III)-mimochrome VI artificial enzymes immobilized on mesoporous ITO electrodes.

    PubMed

    Vitale, R; Lista, L; Lau-Truong, S; Tucker, R T; Brett, M J; Limoges, B; Pavone, V; Lombardi, A; Balland, V

    2014-02-21

    UV-visible absorption spectroelectrochemistry elucidated the different redox behaviours of Fe(III)- and Co(III)-mimochrome VI artificial enzymes, adsorbed on mesoporous conductive films of ITO. The reduction of the ferric complex was rapid and reversible, while the cobaltic complex exhibited irreversible processes probably related to multiple coordination states.

  17. Posttranslational modification and quality control.

    PubMed

    Wang, Xuejun; Pattison, J Scott; Su, Huabo

    2013-01-18

    Protein quality control functions to minimize the level and toxicity of misfolded proteins in the cell. Protein quality control is performed by intricate collaboration among chaperones and target protein degradation. The latter is performed primarily by the ubiquitin-proteasome system and perhaps autophagy. Terminally misfolded proteins that are not timely removed tend to form aggregates. Their clearance requires macroautophagy. Macroautophagy serves in intracellular quality control also by selectively segregating defective organelles (eg, mitochondria) and targeting them for degradation by the lysosome. Inadequate protein quality control is observed in a large subset of failing human hearts with a variety of causes, and its pathogenic role has been experimentally demonstrated. Multiple posttranslational modifications can occur to substrate proteins and protein quality control machineries, promoting or hindering the removal of the misfolded proteins. This article highlights recent advances in posttranslational modification-mediated regulation of intracellular quality control mechanisms and its known involvement in cardiac pathology.

  18. Posttranslational Modification Assays on Functional Protein Microarrays.

    PubMed

    Neiswinger, Johnathan; Uzoma, Ijeoma; Cox, Eric; Rho, HeeSool; Jeong, Jun Seop; Zhu, Heng

    2016-10-03

    Protein microarray technology provides a straightforward yet powerful strategy for identifying substrates of posttranslational modifications (PTMs) and studying the specificity of the enzymes that catalyze these reactions. Protein microarray assays can be designed for individual enzymes or a mixture to establish connections between enzymes and substrates. Assays for four well-known PTMs-phosphorylation, acetylation, ubiquitylation, and SUMOylation-have been developed and are described here for use on functional protein microarrays. Phosphorylation and acetylation require a single enzyme and are easily adapted for use on an array. The ubiquitylation and SUMOylation cascades are very similar, and the combination of the E1, E2, and E3 enzymes plus ubiquitin or SUMO protein and ATP is sufficient for in vitro modification of many substrates.

  19. Self-powered p-NiO/n-ZnO heterojunction ultraviolet photodetectors fabricated on plastic substrates

    SciTech Connect

    Hasan, Md Rezaul; Xie, Ting; Liu, Guannan; Barron, Sara C.; Nguyen, Nhan V.; Motayed, Abhishek; Rao, Mulpuri V.; Debnath, Ratan

    2015-10-01

    A self-powered ultraviolet (UV) photodetector (PD) based on p-NiO and n-ZnO was fabricated using low-temperature sputtering technique on indium doped tin oxide (ITO) coated plastic polyethylene terephthalate (PET) substrates. The p-n heterojunction showed very fast temporal photoresponse with excellent quantum efficiency of over 63% under UV illumination at an applied reverse bias of 1.2 V. The engineered ultrathin Ti/Au top metal contacts and UV transparent PET/ITO substrates allowed the PDs to be illuminated through either frontside or backside. Morphology, structural, chemical, and optical properties of sputtered NiO and ZnO films were also investigated.

  20. Highly efficient blue organic light emitting devices with indium-free transparent anode on flexible substrates

    SciTech Connect

    Wang, Liang; Swensen, James S.; Polikarpov, Evgueni; Matson, Dean W.; Bonham, Charles C.; Bennett, Wendy D.; Gaspar, Daniel J.; Padmaperuma, Asanga B.

    2010-09-30

    Indium-free transparent conducting oxides may provide a lower cost solution for the transparent anode in flexible displays and energy efficient solid state lighting. We report herein a near room temperature sputtering process for generating an indium-free transparent conductive oxide (TCO) coating on a flexible substrate. Specifically, we deposited gallium-doped zinc oxide (GZO) uniformly over a 12” diameter area at room temperature on polyethylene terephthalate (PET). During deposition, the system heats to about 60oC due to the energetic sputtering conditions, without any noticeable damage to the PET substrate. The GZO films exhibit excellent physical, optical and electrical properties: roughness ~7 nm, transmittance >85% and resistivity ~ 10-3 ohm• cm. Phosphorescent blue organic light-emitting devices (OLEDs) were fabricated on these substrates with comparable performance (16% external quantum efficiency and 33 lm/W power efficiency at 1mA/cm2) to that of devices fabricated on GZO (or ITO) deposited on glass substrates, suggesting flexible GZO/PET substrates may be used instead of high-cost and rigid ITO and glass for flexible displays and solid state lighting.

  1. Power electronics substrate for direct substrate cooling

    DOEpatents

    Le, Khiet [Mission Viejo, CA; Ward, Terence G [Redondo Beach, CA; Mann, Brooks S [Redondo Beach, CA; Yankoski, Edward P [Corona, CA; Smith, Gregory S [Woodland Hills, CA

    2012-05-01

    Systems and apparatus are provided for power electronics substrates adapted for direct substrate cooling. A power electronics substrate comprises a first surface configured to have electrical circuitry disposed thereon, a second surface, and a plurality of physical features on the second surface. The physical features are configured to promote a turbulent boundary layer in a coolant impinged upon the second surface.

  2. Surface Modification of Water Purification Membranes.

    PubMed

    Miller, Daniel J; Dreyer, Daniel R; Bielawski, Christopher W; Paul, Donald R; Freeman, Benny D

    2017-04-18

    Polymeric membranes are an energy-efficient means of purifying water, but they suffer from fouling during filtration. Modification of the membrane surface is one route to mitigating membrane fouling, as it helps to maintain high levels of water productivity. Here, a series of common techniques for modification of the membrane surface are reviewed, including surface coating, grafting, and various treatment techniques such as chemical treatment, UV irradiation, and plasma treatment. Historical background on membrane development and surface modification is also provided. Finally, polydopamine, an emerging material that can be easily deposited onto a wide variety of substrates, is discussed within the context of membrane modification. A brief summary of the chemistry of polydopamine, particularly as it may pertain to membrane development, is also described.

  3. Behavior Modification in Coaching.

    ERIC Educational Resources Information Center

    Lynch, Annette Rutt; Stillman, Stephen M.

    1979-01-01

    An example of behavior modification used in athletic coaching is presented. The case study involves a member of a women's basketball team and details the use of behavior modification for both weight reduction and skill improvement. (JMF)

  4. Behavior Modification is not...

    ERIC Educational Resources Information Center

    Tawney, James W.; And Others

    1973-01-01

    Identified are misconceptions of behavior modification procedures according to which behavior modification is connected mistakenly with noncontingent reinforcement, partial change of a teacher's behavior, decelerations of inappropriate behaviors only, dependency producing technology, teacher dominated activity, a single type of classroom…

  5. Structural insights into Parkin substrate lysine targeting from minimal Miro substrates

    PubMed Central

    Klosowiak, Julian L.; Park, Sungjin; Smith, Kyle P.; French, Michael E.; Focia, Pamela J.; Freymann, Douglas M.; Rice, Sarah E.

    2016-01-01

    Hereditary Parkinson’s disease is commonly caused by mutations in the protein kinase PINK1 or the E3 ubiquitin ligase Parkin, which function together to eliminate damaged mitochondria. PINK1 phosphorylates both Parkin and ubiquitin to stimulate ubiquitination of dozens of proteins on the surface of the outer mitochondrial membrane. However, the mechanisms by which Parkin recognizes specific proteins for modification remain largely unexplored. Here, we show that the C-terminal GTPase (cGTPase) of the Parkin primary substrate human Miro is necessary and sufficient for efficient ubiquitination. We present several new X-ray crystal structures of both human Miro1 and Miro2 that reveal substrate recognition and ubiquitin transfer to be specific to particular protein domains and lysine residues. We also provide evidence that Parkin substrate recognition is functionally separate from substrate modification. Finally, we show that prioritization for modification of a specific lysine sidechain of the cGTPase (K572) within human Miro1 is dependent on both its location and chemical microenvironment. Activation of Parkin by phosphorylation or by binding of pUb is required for prioritization of K572 for modification, suggesting that Parkin activation and acquisition of substrate specificity are coupled. PMID:27605430

  6. Readers of histone modifications

    PubMed Central

    Yun, Miyong; Wu, Jun; Workman, Jerry L; Li, Bing

    2011-01-01

    Histone modifications not only play important roles in regulating chromatin structure and nuclear processes but also can be passed to daughter cells as epigenetic marks. Accumulating evidence suggests that the key function of histone modifications is to signal for recruitment or activity of downstream effectors. Here, we discuss the latest discovery of histone-modification readers and how the modification language is interpreted. PMID:21423274

  7. Ito, Stratonovich, Hänggi and all the rest: The thermodynamics of interpretation

    NASA Astrophysics Data System (ADS)

    Sokolov, I. M.

    2010-10-01

    To elucidate a question of the necessity and thermodynamical meaning of the interpretation of Langevin's equations with multiplicative nose, we considered a simple model of particle diffusion in a slowly modulated periodic potential in the low-temperature limit. Our main point is to clarify, what kind of interpretation is appropriate to describe the situation under different types of modulation within the Langevin scheme. The existence of a free interpretation parameter α is a necessity connected with the fact, that the diffusion coefficient D is an amalgam of two kinetic parameters, the period length and the sojourn time in a potential well, which in their turn depend on the microscopic parameters of the model. The results show that the Ito and the Hänggi-Klimontovich interpretations correspond to a trap and barrier models respectively, and that the Fisk-Stratonovich one corresponds to a modulation of the potential's period. All other situations are more complex and may correspond to position-dependent interpretation parameter.

  8. Enhancement of nonlinear optical susceptibility of CuPc films by ITO layer

    NASA Astrophysics Data System (ADS)

    Ganesh, V.; Zahran, H. Y.; Yahia, I. S.; Shkir, Mohd; AlFaify, S.

    2016-12-01

    In the present study, the Copper Phthalocyanine (CuPc)/ITO thin film was fabricated using thermal evaporation method. The structural property was analyzed by X-ray diffraction study and confirms that the thin film has been preferentially grown along (200) plane. The atomic force microscope study was carried out on deposited film and quality of thin films is assessed by calculating the roughness of the films. The direct and indirect band gap, linear and nonlinear optical characteristics of grown films were calculated by using UV-Vis-NIR spectrometer studies. The calculated values of the first direct and indirect band gaps (Eg1(d) &Eg1(ind)) are 1.879 and 1.644 eV as a fundamental gap, while the values of second direct and indirect band gap (Eg2(d) &Eg2(ind)) are 1.660 and 1.498 eV as an onset gap for CuPc. The values of nonlinear refractive index (n2) and third order nonlinear optical susceptibility (χ3) are found to be 5 × 10-8 and 8 × 10-9 (theoretical) and 5.2 × 10-8 and 1.56 × 10-7 (experimental) respectively. The optical band and third order nonlinear properties suggest that the as-prepared films are may be applied in optoelectronic and nonlinear applications.

  9. Effect of substrate temperature on structural, morphological and optical properties of deposited Al/ZnO films

    NASA Astrophysics Data System (ADS)

    Ghorannevis, Z.; Hosseinnejad, M. T.; Habibi, M.; Golmahdi, P.

    2015-12-01

    Al-doped ZnO (Al/ZnO) thin film is a promising alternative to an ITO electrode in solar cell applications due to its low price, non-toxicity and other promising properties. In this paper, Al/ZnO thin films at different substrate temperatures were deposited on glass substrates as transparent conducting (TCO) films by DC magnetron sputtering. The effect of substrate temperature on the structural, morphological and optical properties of Al/ZnO films was investigated. X-ray diffraction (XRD) analysis suggests that crystal structure characteristics of synthesized thin films depend on the substrate temperature. The structure growth and variation in surface roughness with increasing substrate temperature are revealed by scanning electron microscope (SEM) micrographs and atomic force microscopy (AFM) analyses. Thicknesses of the deposited films were also examined by surface profiler. Moreover, obtained results from optical transmission patterns revealed that with the increasing substrate temperature, optical transmittance decreases.

  10. Direct evidence of visible surface plasmon excitation in ITO film coated on LiNbO3 slabs.

    PubMed

    Zhao, Hua; Wang, Yince; Xue, Tingyu; Su, Hang; Zhang, Jingwen

    2017-03-20

    An iron-doped Y-cut lithium niobate (Fe:LN) slab was coated with indium-tin-oxide (ITO) thin films by magnetron sputtering. The electron confinement in a sub-nanometer region at ITO/LN interfaces is resulted from electric screening effect. Consequently, the local plasma frequency in the sub-nanometer metallic-like layer is shifted to the UV regime. This makes it possible to excite surface plasmon polaritons (SPPs) in the visible region with photorefractive phase gratings in the LN slab and to transport SPPs much energy-efficiently. Direct evidence of the excitation of SPPs was demonstrated by the presence of deep transmission spectral valleys in the transmission spectra and striking dark bands in the 2D diffraction patterns while using a white reading beam. Theoretical arguments and confirmation experiments are presented to elucidate all the related findings.

  11. Effect of temperature and NO2 surface adsorption on electrical properties of screen printed ITO thin film

    NASA Astrophysics Data System (ADS)

    Madhi, I.; Meddeb, W.; Bouzid, B.; Saadoun, M.; Bessaïs, B.

    2015-11-01

    Indium tin oxide films with thicknesses of about 1 μm were prepared using the screen printing technique. Preliminary X-ray diffraction studies show that the formed ITO crystallizes in the cubic crystal system. The crystallite size (D) and the microstrain (ɛstr) were investigated using Scherrer formula and Williamson-Hall analysis. Scanning electron microscopy and transmission electron microscopy show that the ITO films are granular, essentially composed of uniformly distributed sub-spherical - like grains. The variation of the DC conductivity with temperature confirms the presence of three activation energies, indicating the presence of different scattering mechanisms essentially dominated by oxygen adsorption and thermal excitation of electrons in the conduction band. Detailed studies of the dielectric parameters (i.e., ɛ* and tan δ) of the compound as a function of temperature and NO2 adsorption (at various range of frequencies) reveal that their values are strongly dependent on temperature and NO2 adsorption.

  12. High Performance Reduction of H2O2 with an Electron Transport Decaheme Cytochrome on a Porous ITO Electrode.

    PubMed

    Reuillard, Bertrand; Ly, Khoa H; Hildebrandt, Peter; Jeuken, Lars J C; Butt, Julea N; Reisner, Erwin

    2017-03-08

    The decaheme cytochrome MtrC from Shewanella oneidensis MR-1 immobilized on an ITO electrode displays unprecedented H2O2 reduction activity. Although MtrC showed lower peroxidase activity in solution compared to horseradish peroxidase, the ten heme cofactors enable excellent electronic communication and a superior activity on the electrode surface. A hierarchical ITO electrode enabled optimal immobilization of MtrC and a high current density of 1 mA cm(-2) at 0.4 V vs SHE could be obtained at pH 6.5 (Eonset = 0.72 V). UV-visible and Resonance Raman spectroelectrochemical studies suggest the formation of a high valent iron-oxo species as the catalytic intermediate. Our findings demonstrate the potential of multiheme cytochromes to catalyze technologically relevant reactions and establish MtrC as a new benchmark in biotechnological H2O2 reduction with scope for applications in fuel cells and biosensors.

  13. Study on the synthesis of Indium Tinoxide (ITO) nanomaterial using sol gel process and its potential for CO gas detection

    NASA Astrophysics Data System (ADS)

    Wiranto, Goib; Idayanti, Novrita; Retnaningsih, Lilis

    2016-11-01

    This paper described the synthesis of doped and undoped nanomaterial Indium Tinoxide (ITO) using sol-gel process with the base materials from Indium Nitride (In(NO3)) and Tin Chloride (SnCl4). Doping was done using Palladium Chloride (PdCl), with the molar ratio of 90:10 and 70:30, respectively. Physical characteristics of the nanocrystallites were examined using SEM, EDS, XRD, and FTIR, whereas its resistivity was tested agaist CO gas. The result showed that the ITO powders have a crystal size smaller than 100 nm, with a cubic crystal structure (byxbite type), and having strong molecular bonds for In-O-In and Sn-O-Sn. The response to CO gases showed a decreasing resistivity with increasing CO gas concentration, showing its potential for gas sensor application.

  14. Modification of heterogeneous chemistry by complex substrate morphology

    SciTech Connect

    Henson, B.F.; Buelow, S.J.; Robinson, J.M.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Chemistry in many environmental systems is determined at some stage by heterogeneous reaction with a surface. Typically the surface exists as a dispersion or matrix of particulate matter or pores, and a determination of the heterogeneous chemistry of the system must address the extent to which the complexity of the environmental surface affects the reaction rates. Reactions that are of current interest are the series of chlorine nitrate reactions important in polar ozone depletion. The authors have applied surface spectroscopic techniques developed at LANL to address the chemistry of chlorine nitrate reactions on porous nitric and sulfuric acid ice surfaces as a model study of the measurement of complex, heterogeneous reaction rates. The result of the study is an experimental determination of the surface coverage of one adsorbed reagent and a mechanism of reactivity based on the dependence of this coverage on temperature and vapor pressure. The resulting mechanism allows the first comprehensive modeling of chlorine nitrate reaction probability data from several laboratories.

  15. Protein modification by adenine propenal.

    PubMed

    Shuck, Sarah C; Wauchope, Orrette R; Rose, Kristie L; Kingsley, Philip J; Rouzer, Carol A; Shell, Steven M; Sugitani, Norie; Chazin, Walter J; Zagol-Ikapitte, Irene; Boutaud, Olivier; Oates, John A; Galligan, James J; Beavers, William N; Marnett, Lawrence J

    2014-10-20

    Base propenals are products of the reaction of DNA with oxidants such as peroxynitrite and bleomycin. The most reactive base propenal, adenine propenal, is mutagenic in Escherichia coli and reacts with DNA to form covalent adducts; however, the reaction of adenine propenal with protein has not yet been investigated. A survey of the reaction of adenine propenal with amino acids revealed that lysine and cysteine form adducts, whereas histidine and arginine do not. N(ε)-Oxopropenyllysine, a lysine-lysine cross-link, and S-oxopropenyl cysteine are the major products. Comprehensive profiling of the reaction of adenine propenal with human serum albumin and the DNA repair protein, XPA, revealed that the only stable adduct is N(ε)-oxopropenyllysine. The most reactive sites for modification in human albumin are K190 and K351. Three sites of modification of XPA are in the DNA-binding domain, and two sites are subject to regulatory acetylation. Modification by adenine propenal dramatically reduces XPA's ability to bind to a DNA substrate.

  16. Electrochemical synthesis of nanocrystalline In2O3:Sn (ITO) in an aqueous system with ammonium acetate as conducting salt.

    PubMed

    Veith, M; Rabung, B; Grobelsek, I; Klook, M; Wagner, F E; Quilitz, M

    2009-04-01

    Nanoscaled so called indium tin oxide In2O3:Sn (ITO) with a specific BET surface area of 50 m2/g to 60 m2/g was prepared via an electrochemical method in an aqueous system containing ammonium acetate as conductive salt. As an intermediate product of the synthesis nanocrystalline In(OH)3 is obtained which serves as a precursor for the subsequent calcinations accompanied by tin doping resulting in ITO powders with various tin concentrations. Its phase transitions and the reduction behaviour of hydroxide to oxide during the calcination process in air flow and forming gas atmosphere of N2 to H2 ratio of 95 to 5 respectively, have been investigated by high temperature X-ray diffraction, TG/DSC/MS, HRTEM and SEM analysis. Depending on the atmosphere dehydration of tin doped In(OH)3 started at 150 degrees C, cubic ITO solid solution formed between 190 degrees C and 300 degrees C. The total weight loss of the hydroxide of approx. 21% occurred mainly below 360 degrees C and the burn-out of organic components mainly between 308 degrees C and 316 degrees C. The results of DSC and MS analyses were in good agreement with the results of the X-ray diffraction. In addition, the products have been characterized by EDX associated with TEM, XPS, ICP-AES, BET analysis and 119Sn Mössbauer spectroscopy. Completely reacted samples of ITO have been processed to pellets, calcined and sintered in the temperature range between 900 degrees C and 1100 degrees C and characterized by measurements of the electrical conductivities of bulk and surface in the reduced as well as in the oxidized state giving values up to 1400 Scm(-1).

  17. Reexcitation mechanisms in epicardial tissue: role of I(to) density heterogeneities and I(Na) inactivation kinetics.

    PubMed

    Cantalapiedra, Inma R; Peñaranda, Angelina; Mont, Lluis; Brugada, Josep; Echebarria, Blas

    2009-08-21

    Dispersion of action potential repolarization is known to be an important arrhythmogenic factor in cardiopathies such as Brugada syndrome. In this work, we analyze the effect of a variation in sodium current (I(Na)) inactivation and a heterogeneous rise of transient outward current (I(to)) in the probability of reentry in epicardial tissue. We use the Luo-Rudy model of epicardial ventricular action potential to study wave propagation in a one-dimensional fiber. Spatial dispersion in repolarization is introduced by splitting the fiber into zones with different strength of I(to). We then analyze the pro-arrhythmic effect of a variation in the relaxation time and steady-state of the sodium channel fast inactivating gate h. We quantify the probability of reentry measuring the percentage of reexcitations that occurs in 200 beats. We find that, for high stimulation rates, this percentage is negligible, but increases notably for pacing periods above 700ms. Surprisingly, with decreasing I(Na) inactivation time, the percentage of reexcitations does not grow monotonically, but presents vulnerable windows, separated by values of the I(Na) inactivation speed-up where reexcitation does not occur. By increasing the strength of L-type calcium current I(CaL) above a certain threshold, reexcitation disappears. Finally, we show the formation of reentry in stimulated two-dimensional epicardial tissue with modified I(Na) kinetics and I(to) heterogeneity. Thus, we confirm that while I(to) dispersion is necessary for phase-2 reentry, altered sodium inactivation kinetics influences the probability of reexcitation in a highly nonlinear fashion.

  18. Surface plasmon resonance based fiber optic pH sensor utilizing Ag/ITO/Al/hydrogel layers.

    PubMed

    Mishra, Satyendra K; Gupta, Banshi D

    2013-05-07

    The fabrication and characterization of a surface plasmon resonance based pH sensor using coatings of silver, ITO (In2O3:SnO2), aluminium and smart hydrogel layers over an unclad core of an optical fiber have been reported. The silver, aluminium and ITO layers were coated using a thermal evaporation technique, while the hydrogel layer was prepared using a dip-coating method. The sensor works on the principle of detecting changes in the refractive index of the hydrogel layer due to its swelling and shrinkage caused by changes in the pH of the fluid surrounding the hydrogel layer. The sensor utilizes a wavelength interrogation technique and operates in a particular window of low and high pH values. Increasing the pH value of the fluid causes swelling of the hydrogel layer, which decreases its refractive index and results in a shift of the resonance wavelength towards blue in the transmitted spectra. The thicknesses of the ITO and aluminium layers have been optimized to achieve the best performance of the sensor. The ITO layer increases the sensitivity while the aluminium layer increases the detection accuracy of the sensor. The proposed sensor possesses maximum sensitivity in comparison to the sensors reported in the literature. A negligible effect of ambient temperature in the range 25 °C to 45 °C on the performance of the sensor has been observed. The additional advantages of the sensor are short response time, low cost, probe miniaturization, probe re-usability and the capability of remote sensing.

  19. Direct electrical contact of slanted ITO film on axial p-n junction silicon nanowire solar cells.

    PubMed

    Lee, Ya-Ju; Yao, Yung-Chi; Yang, Chia-Hao

    2013-01-14

    A novel scheme of direct electrical contact on vertically aligned silicon nanowire (SiNW) axial p-n junction is demonstrated by means of oblique-angle deposition of slanted indium-tin-oxide (ITO) film for photovoltaic applications. The slanted ITO film exhibits an acceptable resistivity of 1.07 x 10⁻³Ω-cm underwent RTA treatment of T = 450°C, and the doping concentration and carrier mobility by Hall measurement amount to 3.7 x 10²⁰ cm⁻³ and 15.8 cm²/V-s, respectively, with an n-type doping polarity. Because of the shadowing effect provided by the SiNWs, the incident ITO vapor-flow is deposited preferentially on the top of SiNWs, which coalesces and eventually forms a nearly continuous film for the subsequent fabrication of grid electrode. Under AM 1.5 G normal illumination, our axial p-n junction SiNW solar cell exhibits an open circuit voltage of VOC = 0.56 V, and a short circuit current of JSC = 1.54 mA/cm² with a fill factor of FF = 30%, resulting in a total power conversion efficiency of PEC = 0.26%.

  20. Modulation of the transient outward current (Ito) in rat cardiac myocytes and human Kv4.3 channels by mefloquine.

    PubMed

    Perez-Cortes, E J; Islas, A A; Arevalo, J P; Mancilla, C; Monjaraz, E; Salinas-Stefanon, E M

    2015-10-15

    The antimalarial drug mefloquine, is known to be a potassium channel blocker, although its mechanism of action has not being elucidated and its effects on the transient outward current (Ito) and the molecular correlate, the Kv4.3 channel has not being studied. Here, we describe the mefloquine-induced inhibition of the rat ventricular Ito and of CHO cells co-transfected with human Kv4.3 and its accessory subunit hKChIP2C by whole-cell voltage-clamp. Mefloquine inhibited rat Ito and hKv4.3+KChIP2C currents in a concentration-dependent manner with a limited voltage dependence and similar potencies (IC50=8.9μM and 10.5μM for cardiac myocytes and Kv4.3 channels, respectively). In addition, mefloquine did not affect the activation of either current but significantly modified the hKv4.3 steady-state inactivation and recovery from inactivation. The effects of this drug was compared with that of 4-aminopyridine (4-AP), a well-known potassium channel blocker and its binding site does not seem to overlap with that of 4-AP.

  1. Hybrid solar cells based on dc magnetron sputtered films of n-ITO on APMOVPE grown p-InP

    NASA Technical Reports Server (NTRS)

    Coutts, T. J.; Li, X.; Wanlass, M. W.; Emery, K. A.; Gessert, T. A.

    1988-01-01

    Hybrid indium-tin-oxide (ITO)/InP solar cells are discussed. The cells are constructed by dc magnetron sputter deposition of ITO onto high-quality InP films grown by atmospheric pressure metal-organic vapor-phase epitaxy (APMOVPE). A record efficiency of 18.9 percent, measured under standard Solar Energy Research Institute reporting conditions, has been obtained. The p-InP surface is shown to be type converted, principally by the ITO, but with the extent of conversion being modified by the nature of the sputtering gas. The deposition process, in itself, is not responsible for the type conversion. Dark currents have been suppressed by more than three orders of magnitude by the addition of hydrogen to the sputtering gas during deposition of a thin (5 nm) interface layer. Without this layer, and using only the more usual argon/oxygen mixture, the devices had poorer efficiencies and were unstable. A discussion of associated quantum efficiencies and capacitance/voltage measurements is also presented from which it is concluded that further improvements in efficiency will result from better control over the type-conversion process.

  2. Polycrystalline PLZT/ITO Ceramic Electro-Optic Phase Gratings: Electro- Optically Reconfigurable Diffractive Devices for Free-Space and In-Wafer Interconnects

    DTIC Science & Technology

    1994-09-01

    free-space and waveguide interconnects is investigated through the fabrication, testing and modeling of polycrystalline PLZT/ITO ceramic electro - optic phase...only gratings. PLZT Diffraction grating, Electro - optic diffraction grating, Optical switching, Optical interconnects, Reconfigurable interconnect

  3. Preparation of ITO/SiO{sub x}/n-Si solar cells with non-decline potential field and hole tunneling by magnetron sputtering

    SciTech Connect

    Du, H. W.; Yang, J.; Li, Y. H.; Xu, F.; Xu, J.; Ma, Z. Q.

    2015-03-02

    Complete photo-generated minority carrier's quantum tunneling device under AM1.5 illumination is fabricated by depositing tin-doped indium oxide (ITO) on n-type silicon to form a structure of ITO/SiO{sub x}/n-Si heterojunction. The work function difference between ITO and n-Si materials essentially acts as the origin of built-in-field. Basing on the measured value of internal potential (V{sub bi} = 0.61 V) and high conversion efficiency (9.27%), we infer that this larger photo-generated holes tunneling occurs when a strong inversion layer at the c-Si surface appears. Also, the mixed electronic states in the ultra-thin intermediate region between ITO and n-Si play a defect-assisted tunneling.

  4. Surface modification to prevent oxide scale spallation

    DOEpatents

    Stephens, Elizabeth V; Sun, Xin; Liu, Wenning; Stevenson, Jeffry W; Surdoval, Wayne; Khaleel, Mohammad A

    2013-07-16

    A surface modification to prevent oxide scale spallation is disclosed. The surface modification includes a ferritic stainless steel substrate having a modified surface. A cross-section of the modified surface exhibits a periodic morphology. The periodic morphology does not exceed a critical buckling length, which is equivalent to the length of a wave attribute observed in the cross section periodic morphology. The modified surface can be created using at least one of the following processes: shot peening, surface blasting and surface grinding. A coating can be applied to the modified surface.

  5. Role of the Ito cell in liver parenchymal fibrosis in rats fed alcohol and a high fat-low protein diet.

    PubMed Central

    French, S. W.; Miyamoto, K.; Wong, K.; Jui, L.; Briere, L.

    1988-01-01

    Eight pairs of young adult rats were pair-fed a high fat-low protein diet and ethanol or isocaloric glucose by permanent intragastric cannula for up to 6 months. Biopsies of the liver were taken monthly and the fibrosis was quantitated morphometrically using the sirius red polarization method of collagen visualization by light microscopy. Morphometric analysis of the sinusoids and scars were performed on electron micrographs made from the liver biopsies. An increase in the collagen in both the central and portal areas was found when the livers of the alcohol-fed rats were compared with controls. The predominant cell in the scars was the Ito cell. An increase in the percentage of the total Ito cell square area made up of rough endoplasmic reticulum (RER) was noted when the sinusoids of the liver of the ethanol-fed rats were compared with controls. No difference in the RER was found when the sinusoidal Ito cells were compared with the Ito cells located within the scars of the ethanol-fed rats. It was concluded that Ito cell "activation" by chronic ethanol feeding in the sinusoids of rats accurately predicts "activation" of the Ito cells within scars. The Ito cells are diffusely activated even though the scarring is localized. This implies that local factors as well as Ito cell activation are necessary for scar formation. In the case of alcoholic liver disease, scar formation may be initiated by centrilobular necrosis. Images Figure 2 Figure 3 Figure 4 Figure 5 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 PMID:3394803

  6. Enhanced power efficiency of ZnO based organic/inorganic solar cells by surface modification

    NASA Astrophysics Data System (ADS)

    Tang, Shuangshuang; Tang, Ning; Meng, Xiuqing; Huang, Shihua; Hao, Yafei

    2016-09-01

    We present series of strategies to enhance efficiency of ZnO nanorods based organic/inorganic solar cells with spin-coated P3HT:PCBM blend as active layer. The performance of the as-fabricated devices is improved by controlling the size of ZnO nanorods, annealing temperature and time of active layer, surface modification of ZnO with PSBTBT. Optimized device of ITO/ZnO nanorod/P3HT:PCBM/Ag device with PSBTBT surface modification and air exposure reaches an efficiency of 2.02% with a short-circuit current density, open-circuit voltage and fill factor of 13.23 mA cm-2, 0.547 V and 28%, respectively, under AM 1.5 irradiation of 100 mW m-2, the increase in efficiency is 7-fold of the PSBTBT surface modified ITO/ZnO nanorods/P3HT:PCBM/Ag device compared with the unmodified one, which is own to the increased interface contact, expanded light absorption, tailored band alignment attributed to PSBTBT. We found exposure to air and surface modification is crucial to improve the device performance, and we discussed the mechanisms that affect the performance of the devices in detail.

  7. Salami-like Electrospun Si Nanoparticle-ITO Composite Nanofibers with Internal Conductive Pathways for use as Anodes for Li-Ion Batteries.

    PubMed

    Lee, Daehee; Kim, Bokyung; Kim, Joosun; Jeong, Sunho; Cao, Guozhong; Moon, Jooho

    2015-12-16

    We report novel salami-like core-sheath composites consisting of Si nanoparticle assemblies coated with indium tin oxide (ITO) sheath layers that are synthesized via coelectrospinning. Core-sheath structured Si nanoparticles (NPs) in static ITO allow robust microstructures to accommodate for mechanical stress induced by the repeated cyclical volume changes of Si NPs. Conductive ITO sheaths can provide bulk conduction paths for electrons. Distinct Si NP-based core structures, in which the ITO phase coexists uniformly with electrochemically active Si NPs, are capable of facilitating rapid charge transfer as well. These engineered composites enabled the production of high-performance anodes with an excellent capacity retention of 95.5% (677 and 1523 mAh g(-1,) which are based on the total weight of Si-ITO fibers and Si NPs only, respectively), and an outstanding rate capability with a retention of 75.3% from 1 to 12 C. The cycling performance and rate capability of core-sheath-structured Si NP-ITO are characterized in terms of charge-transfer kinetics.

  8. Merits and Demerits of Transparent Conducting Magnetron Sputtered ZnO:Al, ITO and SnO2:F Thin Films for Solar Cell Applications

    NASA Astrophysics Data System (ADS)

    Das, Rajesh; Das, Himadri Sekhar

    2017-04-01

    Transparent conducting ZnO:Al and indium tin oxide (ITO) thin films were deposited by magnetron sputtering under reactive environment. Both the transparent conducting oxide (TCO) films were exposed intentionally in hydrogen environment at 350 °C calcinations temperature to study the post treated TCO film's opto-electronic, structural as well as surface morphological properties. Electrical resistivity of both ZnO:Al, ITO and SnO2:F films are comparable (order of 10-4 Ω-cm), lowest sheet resistance are 8.5, 3.7 and 4.6 Ω/sq respectively and slightly improved after hydrogen exposure at 350 °C. Optical transmittance and internal texture of hydrogen environment exposed ZnO films remains invariant, but in case of ITO, SnO2:F films optical transmittance deteriorated drastically. Hexagonal wurtzite structure with (002) c-axis orientation is observed for pre- and post-hydrogen exposed ZnO films whereas internal texture as well as crystallographic orientation of ITO and SnO2:F films have significantly changed. Surface grains of ITO films have been significantly enhanced, but no such variations are observed in ZnO surface morphology. ZnO:Al and ITO films show unique plasmonic properties in near infrared transmittance due to free carrier generation in conduction band. Based on surface features/morphology, haze factor and internal texture light scattering mechanism is modeled.

  9. Merits and Demerits of Transparent Conducting Magnetron Sputtered ZnO:Al, ITO and SnO2:F Thin Films for Solar Cell Applications

    NASA Astrophysics Data System (ADS)

    Das, Rajesh; Das, Himadri Sekhar

    2016-06-01

    Transparent conducting ZnO:Al and indium tin oxide (ITO) thin films were deposited by magnetron sputtering under reactive environment. Both the transparent conducting oxide (TCO) films were exposed intentionally in hydrogen environment at 350 °C calcinations temperature to study the post treated TCO film's opto-electronic, structural as well as surface morphological properties. Electrical resistivity of both ZnO:Al, ITO and SnO2:F films are comparable (order of 10-4 Ω-cm), lowest sheet resistance are 8.5, 3.7 and 4.6 Ω/sq respectively and slightly improved after hydrogen exposure at 350 °C. Optical transmittance and internal texture of hydrogen environment exposed ZnO films remains invariant, but in case of ITO, SnO2:F films optical transmittance deteriorated drastically. Hexagonal wurtzite structure with (002) c-axis orientation is observed for pre- and post-hydrogen exposed ZnO films whereas internal texture as well as crystallographic orientation of ITO and SnO2:F films have significantly changed. Surface grains of ITO films have been significantly enhanced, but no such variations are observed in ZnO surface morphology. ZnO:Al and ITO films show unique plasmonic properties in near infrared transmittance due to free carrier generation in conduction band. Based on surface features/morphology, haze factor and internal texture light scattering mechanism is modeled.

  10. Metabolic regulation of histone post-translational modifications

    PubMed Central

    Fan, Jing; Krautkramer, Kimberly A.; Feldman, Jessica L.; Denu, John M.

    2015-01-01

    Histone post-translational modifications regulate transcription and other DNA-templated functions. This process is dynamically regulated by specific modifying enzymes whose activities require metabolites that either serve as co-substrates or act as activators/inhibitors. Therefore, metabolism can influence histone modification by changing local concentrations of key metabolites. Physiologically, the epigenetic response to metabolism is important for nutrient sensing and environment adaption. In pathologic states, the connection between metabolism and histone modification mediates epigenetic abnormality in complex disease. In this review, we summarize recent studies of the molecular mechanisms involved in metabolic regulation of histone modifications and discuss their biological significance. PMID:25562692

  11. Substrate control in stereoselective lanthionine biosynthesis

    NASA Astrophysics Data System (ADS)

    Tang, Weixin; Jiménez-Osés, Gonzalo; Houk, K. N.; van der Donk, Wilfred A.

    2015-01-01

    Enzymes are typically highly stereoselective catalysts that enforce a reactive conformation on their native substrates. We report here a rare example in which the substrate controls the stereoselectivity of an enzyme-catalysed Michael-type addition during the biosynthesis of lanthipeptides. These natural products contain thioether crosslinks formed by a cysteine attack on dehydrated Ser and Thr residues. We demonstrate that several lanthionine synthetases catalyse highly selective anti-additions in which the substrate (and not the enzyme) determines whether the addition occurs from the re or si face. A single point mutation in the peptide substrate completely inverted the stereochemical outcome of the enzymatic modification. Quantum mechanical calculations reproduced the experimentally observed selectivity and suggest that conformational restraints imposed by the amino-acid sequence on the transition states determine the face selectivity of the Michael-type cyclization.

  12. Ribbed electrode substrates

    DOEpatents

    Breault, Richard D.; Goller, Glen J.

    1983-01-01

    A ribbed substrate for an electrochemical cell electrode is made from a mixture of carbon fibers and carbonizable resin and has a mean pore size in the ribs which is 60-75% of the mean pore size of the web portions of the substrate which interconnect the ribs. Preferably the mean pore size of the web portion is 25-45 microns; and, if the substrate includes edge seals parallel to the ribs, the edge seals preferably have a mean pore size no greater than about ten microns. Most preferably the substrate has the same ratio of carbon fibers to polymeric carbon in all areas, including the ribs, webs, and edge seals. A substrate according to the present invention will have better overall performance than prior art substrates and minimizes the substrate thickness required for the substrate to perform all its functions well.

  13. Coated substrates and process

    DOEpatents

    Chu, Wei-kan; Childs, Charles B.

    1991-01-01

    Disclosed herein is a coated substrate and a process for forming films on substrates and for providing a particularly smooth film on a substrate. The method of this invention involves subjecting a surface of a substrate to contact with a stream of ions of an inert gas having sufficient force and energy to substantially change the surface characteristics of said substrate, and then exposing a film-forming material to a stream of ions of an inert gas having sufficient energy to vaporize the atoms of said film-forming material and to transmit the vaporized atoms to the substrate surface with sufficient force to form a film bonded to the substrate. This process is particularly useful commercially because it forms strong bonds at room temperature. This invention is particularly useful for adhering a gold film to diamond and forming ohmic electrodes on diamond, but also can be used to bond other films to substrates.

  14. Polished polymide substrate

    DOEpatents

    Farah, John; Sudarshanam, Venkatapuram S.

    2003-05-13

    Polymer substrates, in particular polyimide substrates, and polymer laminates for optical applications are described. Polyimide substrates are polished on one or both sides depending on their thickness, and single-layer or multi-layer waveguide structures are deposited on the polished polyimide substrates. Optical waveguide devices are machined by laser ablation using a combination of IR and UV lasers. A waveguide-fiber coupler with a laser-machined groove for retaining the fiber is also disclosed.

  15. Basic Behavior Modification.

    ERIC Educational Resources Information Center

    Mehrabian, Albert

    This monograph examines the component parts of behavior modification, initially defining the problem behavior and drawing a difference between specific observable behaviors (the focus of behavior modification), and the interest of Freudian and similar psychologies in unobservable internal processes. Instrumental learning related to shaping in…

  16. Permit application modifications

    SciTech Connect

    1995-11-01

    This document contains the Permit Application Modifications for the Y-12 Industrial Landfill V site on the Oak Ridge Reservation. These modifications include the assessment of stability of the proposed Landfill V under static and loading conditions. Analyses performed include the general slope stability, veneer stability of the bottom liner and cover system, and a liquefaction potential assessment of the foundation soils.

  17. Zinc-embedded silica nanoparticle layer in a multilayer coating on a glass substrate achieves broadband antireflection and high transparency

    NASA Astrophysics Data System (ADS)

    Kim, Sang Woo; Bae, Dong-Sik; Shin, Hyunho

    2004-12-01

    A zinc-embedded silica (Zn-SiO2) nanoparticle layer has been applied as the outermost layer over the three-layer coating system, Zn-SiO2/SiO2/ITO (indium tin oxide), coated on a soda-lime glass substrate. The additional coating of the zinc-embedded nanoparticle layer over the 2-layer/glass, i.e., SiO2/ITO /glass system, yielded a significant diminution in reflectance, as well as an improved transmittance as compared to the 2-layer/glass system. Plausible mechanisms responsible for such phenomena are discussed. The application of the zinc-embedded silica nanoparticle layer to the multilayer coating system is shown to provide a flexible way to achieve a broadband antireflection and a high transmission.

  18. Flexible transparent memory cell: bipolar resistive switching via indium-tin oxide nanowire networks on a poly(dimethylsiloxane) substrate

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Tian, Zhenhuan; Shang, Geng; Wang, Jiangteng; Li, Yufeng; Yun, Feng

    2016-11-01

    This report describes the fabrication and resistive switching (RS) characteristics of a novel flexible transparent (FT) resistive random access memory (ReRAM) device with a Ag/indium-tin oxide (ITO) nanowire network/ITO capacitor deposited on a PDMS substrate. The transmittance of the device is ˜70% in the visible region, and it exhibits a stable high-resistance state (HRS) to low-resistance state (LRS) ratio (HRS/LRS ratio) in different bending states. The RS characteristics are attributed to the congregate state of oxygen vacancies at different voltages, and the difference between positive and negative bending is mainly contributed by the effect of stress on the conductive layer. The FT-ReRAM can be used as nonvolatile memory element in future flexible transparent devices.

  19. Thin Film Photovoltaic Cells on Flexible Substrates Integrated with Energy Storage

    DTIC Science & Technology

    2011-11-30

    gel sulfurization methods[14], sol - gel spin-coated deposition[15] and spray pyrolysis[ 16,17][16-18]. In addition, there is synthesis based on...93 (2009) 583. [15] M.M.Y. Yeh, J. Sol Gel Sci. Technol. 52 (2009) 65. [16]N.Nakayama, K. Ito, Appl. Surf. Sci. 92 (1996) 171. [17] N. Kamoun, H...777-6598 Standard Form 298 (Rev. 8/98) Prescnbed by ANSI Std, Z39 18 Adobe Professional 7.0 . Thin Film Photovoltaic Cells on Flexible Substrates

  20. Chemical Vapour Deposition of Graphene with Re-useable Pt and Cu substrates for Flexible Electronics

    NASA Astrophysics Data System (ADS)

    Karamat, Shumaila; Sonusen, Selda; Celik, Umit; Uysalli, Yigit; Oral, Ahmet

    2015-03-01

    Graphene has gained the attention of scientific world due to its outstanding physical properties. The future demand of flexible electronics such as solar cells, light emitting diodes, photo-detectors and touch screen technology requires more exploration of graphene properties on flexible substrates. The most interesting application of graphene is in organic light emitting diodes (OLED) where efforts are in progress to replace brittle indium tin oxide (ITO) electrode with a flexible graphene electrode because ITO raw materials are becoming increasingly expensive, and its brittle nature makes it unsuitable for flexible devices. In this work, we grow graphene on Pt and Cu substrates using chemical vapour deposition (CVD) and transferred it to a polymer material (PVA) using lamination technique. We used hydrogen bubbling method for separating graphene from Pt and Cu catalyst to reuse the substrates many times. After successful transfer of graphene on polymer samples, we checked the resistivity values of the graphene sheet which varies with growth conditions. Furthermore, Raman, atomic force microscopy (AFM), I-V and Force-displacement measurements will be presented for these samples.

  1. Reproducible and recyclable SERS substrates: Flower-like Ag structures with concave surfaces formed by electrodeposition

    NASA Astrophysics Data System (ADS)

    Bian, Juncao; Shu, Shiwei; Li, Jianfu; Huang, Chao; Li, Yang Yang; Zhang, Rui-Qin

    2015-04-01

    Direct synthesis of three-dimensional Ag structures on solid substrates for the purposes of producing reproducible and recyclable surface-enhanced Raman scattering (SERS) applications remains challenging. In this work, flower-like Ag structures with concave surfaces (FACS) were successfully electrodeposited onto ITO glass using the double-potentiostatic method. The FACS, with an enhancement factor of the order of 108, exhibited a SERS signal intensity 3.3 times stronger than that measured from Ag nanostructures without concave surfaces. A cleaning procedure involving lengthy immersion of the sample in ethanol and KNO3 was proposed to recycle the substrate and confirmed by using rhodamine 6G, adenine, and 4-aminothiophenol as target molecules. The findings can help to advance the practical applications of Ag nanostructure-based SERS substrates.

  2. Optical absorption enhancement in a hybrid system photonic crystal - thin substrate for photovoltaic applications.

    PubMed

    Buencuerpo, Jeronimo; Munioz-Camuniez, Luis E; Dotor, Maria L; Postigo, Pablo A

    2012-07-02

    A hybrid approach for light trapping using photonic crystal nanostructures (nanorods, nanopillars or nanoholes) on top of an ultra thin film as a substrate is presented. The combination of a nanopatterned layer with a thin substrate shows an enhanced optical absorption than equivalent films without patterning and can compete in performance with nanostructured systems without a substrate. The designs are tested in four relevant materials: amorphous silicon (a-Si), crystalline silicon (Si), gallium arsenide (GaAs) and indium phosphide (InP). A consistent enhancement is observed for all of the materials when using a thin hybrid system (300 nm) even compared to the non patterned thin film with an anti-reflective coating (ARC). A realistic solar cell structure composed of a hybrid system with a layer of indium tin oxide (ITO) an ARC and a back metal layer is performed, showing an 18% of improvement for the nanostructured device.

  3. Enhanced resistive switching characteristics in Pt/BaTiO3/ITO structures through insertion of HfO2:Al2O3 (HAO) dielectric thin layer

    PubMed Central

    Silva, J. P. B.; Faita, F. L.; Kamakshi, K.; Sekhar, K. C.; Moreira, J. Agostinho; Almeida, A.; Pereira, M.; Pasa, A. A.; Gomes, M. J. M.

    2017-01-01

    An enhanced resistive switching (RS) effect is observed in Pt/BaTiO3(BTO)/ITO ferroelectric structures when a thin HfO2:Al2O3 (HAO) dielectric layer is inserted between Pt and BTO. The P-E hysteresis loops reveal the ferroelectric nature of both Pt/BTO/ITO and Pt/HAO/BTO/ITO structures. The relation between the RS and the polarization reversal is investigated at various temperatures in the Pt/HAO/BTO/ITO structure. It is found that the polarization reversal induces a barrier variation in the Pt/HAO/BTO interface and causes enhanced RS, which is suppressed at Curie temperature (Tc = 140 °C). Furthermore, the Pt/HAO/BTO/ITO structures show promising endurance characteristics, with a RS ratio >103 after 109 switching cycles, that make them potential candidates for resistive switching memory devices. By combining ferroelectric and dielectric layers this work provides an efficient way for developing highly efficient ferroelectric-based RS memory devices.

  4. Recovery Act: Low Cost Integrated Substrate for OLED Lighting Development

    SciTech Connect

    Benton, Scott; Bhandari, Abhinav

    2012-12-26

    PPG pursued the development of an integrated substrate, including the anode, external, and internal extraction layers. The objective of PPG's program was to achieve cost reductions by displacing the existing expensive borosilicate or double-side polished float glass substrates and developing alternative electrodes and scalable light extraction layer technologies through focused and short-term applied research. One of the key highlights of the project was proving the feasibility of using PPG's high transmission Solarphire® float glass as a substrate to consistently achieve organic lightemitting diode (OLED) devices with good performance and high yields. Under this program, four low-cost alternatives to the Indium Tin Oxide (ITO) anode were investigated using pilot-scale magnetron sputtered vacuum deposition (MSVD) and chemical vapor deposition (CVD) technologies. The anodes were evaluated by fabricating small and large phosphorescent organic lightemitting diode (PHOLED) devices at Universal Display Corporation (UDC). The device performance and life-times comparable to commercially available ITO anodes were demonstrated. A cost-benefit analysis was performed to down-select two anodes for further low-cost process development. Additionally, PPG developed and evaluated a number of scalable and compatible internal and external extraction layer concepts such as scattering layers on the outside of the glass substrate or between the transparent anode and the glass interface. In one external extraction layer (EEL) approach, sol-gel sprayed pyrolytic coatings were deposited using lab scale equipment by hand or automated spraying of sol-gel solutions on hot glass, followed by optimizing of scattering with minimal absorption. In another EEL approach, PPG tested large-area glass texturing by scratching a glass surface with an abrasive roller and acid etching. Efficacy enhancements of 1.27x were demonstrated using white PHOLED devices for 2.0mm substrates which are at par with

  5. Large optical nonlinearity of ITO nanorods for sub-picosecond all-optical modulation of the full-visible spectrum

    PubMed Central

    Guo, Peijun; Schaller, Richard D.; Ocola, Leonidas E.; Diroll, Benjamin T.; Ketterson, John B.; Chang, Robert P. H.

    2016-01-01

    Nonlinear optical responses of materials play a vital role for the development of active nanophotonic and plasmonic devices. Optical nonlinearity induced by intense optical excitation of mobile electrons in metallic nanostructures can provide large-amplitude, dynamic tuning of their electromagnetic response, which is potentially useful for all-optical processing of information and dynamic beam control. Here we report on the sub-picosecond optical nonlinearity of indium tin oxide nanorod arrays (ITO-NRAs) following intraband, on-plasmon-resonance optical pumping, which enables modulation of the full-visible spectrum with large absolute change of transmission, favourable spectral tunability and beam-steering capability. Furthermore, we observe a transient response in the microsecond regime associated with slow lattice cooling, which arises from the large aspect-ratio and low thermal conductivity of ITO-NRAs. Our results demonstrate that all-optical control of light can be achieved by using heavily doped wide-bandgap semiconductors in their transparent regime with speed faster than that of noble metals. PMID:27682836

  6. Zero added oxygen for high quality sputtered ITO: A data science investigation of reduced Sn-content and added Zr

    SciTech Connect

    Peshek, Timothy J.; Burst, James M.; Coutts, Timothy J.; Gessert, Timothy A.

    2016-03-15

    The authors demonstrate mobilities of >45 cm{sup 2}/V s for sputtered tin-doped indium oxide (ITO) films at zero added oxygen. All films were deposited with 5 wt. % SnO{sub 2}, instead of the more conventional 8–10 wt. %, and had varying ZrO{sub 2} content from 0 to 3 wt. %, with a subsequent reduction in In{sub 2}O{sub 3} content. These films were deposited by radio-frequency magnetron sputtering from nominally stoichiometric targets with varying oxygen partial pressure in the sputter ambient. Anomalous behavior was discovered for films with no Zr-added, where a bimodality of high and low mobilities was discovered for nominally similar growth conditions. However, all films showed the lowest resistivity and highest mobilities when the oxygen partial pressure in the sputter ambient was zero. This result is contrasted with several other reports of ITO transport performance having a maximum for small but nonzero oxygen partial pressure. This result is attributed to the reduced concentration of SnO{sub 2}. The addition of ZrO{sub 2} yielded the highest mobilities at >55 cm{sup 2}/V s and the films showed a modest increase in optical transmission with increasing Zr-content.

  7. Berberine alleviates ischemic arrhythmias via recovering depressed I(to) and I(Ca) currents in diabetic rats.

    PubMed

    Wang, Li-Hong; Li, Xue-Lian; Li, Qiang; Fu, Ying; Yu, Hai-Jing; Sun, Yu-Qian; Zhang, Li; Shan, Hong-Li

    2012-02-15

    The present study was designed to elucidate the potential mechanism underlying that berberine suppressed ischemic arrhythmias in a rat model of diabetes mellitus (DM). Streptozotocin (STZ)-induced diabetic rats were subjected to ischemia by the occlusion of left anterior descending (LAD) coronary artery. Berberine was orally administered for 7 days before ischemic injury in diabetic rats. Whole-cell patch-clamp was performed to measure the transient outward K⁺ current (I(to)) and L-type Ca²⁺ current (I(Ca)). Results showed that oral administration of berberine (100 mg/kg) attenuated ischemia-induced arrhythmias in diabetic rats. Berberine significantly shortened the prolonged QTc interval from 214 ± 6ms to 189 ± 5ms in ischemic diabetic rats, and also restored the diminished I(to) and I(Ca) current densities in the same animal model rats. In conclusion, the ability of berberine to protect diabetic rats against cardiac arrhythmias makes it possible to be a prospective therapeutic agent in clinical management of cardiac disease secondary to diabetes.

  8. Use of two-dimensional nanorod arrays with slanted ITO film to enhance optical absorption for photovoltaic applications.

    PubMed

    Yao, Yung-Chi; Tsai, Meng-Tsan; Hsu, Hsu-Cheng; She, Li-Wei; Cheng, Chun-Mao; Chen, Yi-Ching; Wu, Chien-Jang; Lee, Ya-Ju

    2012-02-13

    Two-dimensional (2D) Si-nanorod arrays offer a promising architecture that has been widely recognized as attractive devices for photovoltaic applications. To further reduce the Fresnel reflection that occurs at the interface between the air and the 2D Si-nanorod array because of the large difference in their effective refractive indices, we propose and adopt a slanted ITO film as an intermediate layer by using oblique-angle sputtering deposition. The nearly continuous surface of the slanted ITO film is lossless and has high electrical conductivity; therefore, it could serve as an electrode layer for solar cells. As a result, the combination of the above-mentioned nanostructures exhibits high optical absorption over a broad range of wavelengths and incident angles, along with a calculated short-circuit current density of JSC = 32.81 mA/cm2 and a power generation efficiency of η = 22.70%, which corresponds to an improvement of approximately 42% over that of its bare single-crystalline Si counterpart.

  9. Electroluminescence enhancement of glass/ITO/PEDOT:PSS/MEH-PPV/PEDOT:PSS/Al OLED by thermal annealing

    NASA Astrophysics Data System (ADS)

    Hewidy, Dina; Gadallah, A.-S.; Fattah, G. Abdel

    2017-02-01

    Manufacturing of glass/ITO/PEDOT:PSS/MEH-PPV/PEDOT:PSS/Al organic light emitting diode (OLED) by depositing PEDOT:PSS/MEH-PPV/PEDOT:PSS using spin coating has been reported. The roles of PEDOT:PSS in the structure have been reported. It allows transportation of holes from ITO to the highest occupied molecular orbit (HOMO) of MEH-PPV. In additions, it allows transportation of electrons from Al to lowest unoccupied molecular orbit (LUMO) of MEH:PPV. Further, it confines electrons in the LUMO of MEH:PPV due to the higher barrier of PEDOT:PSS of LUMO. The effect of thermal annealing on the current-voltage curve as well as on the electroluminescence intensity has been reported. The results show that the current increased from 25 mA to 52 mA at 7 V, when the sample was thermally annealed at 150 °C. Such enhancement in electrical injection leads to enhancement of the electroluminescence to a factor of 4.7 at the peak luminescence wavelength (∼592 nm). Reasons for electroluminescence improvement caused by thermal annealing have been proposed.

  10. Existence and numerical simulation of periodic traveling wave solutions to the Casimir equation for the Ito system

    NASA Astrophysics Data System (ADS)

    Abbasbandy, S.; Van Gorder, R. A.; Hajiketabi, M.; Mesrizadeh, M.

    2015-10-01

    We consider traveling wave solutions to the Casimir equation for the Ito system (a two-field extension of the KdV equation). These traveling waves are governed by a nonlinear initial value problem with an interesting nonlinearity (which actually amplifies in magnitude as the size of the solution becomes small). The nonlinear problem is parameterized by two initial constant values, and we demonstrate that the existence of solutions is strongly tied to these parameter values. For our interests, we are concerned with positive, bounded, periodic wave solutions. We are able to classify parameter regimes which admit such solutions in full generality, thereby obtaining a nice existence result. Using the existence result, we are then able to numerically simulate the positive, bounded, periodic solutions. We elect to employ a group preserving scheme in order to numerically study these solutions, and an outline of this approach is provided. The numerical simulations serve to illustrate the properties of these solutions predicted analytically through the existence result. Physically, these results demonstrate the existence of a type of space-periodic structure in the Casimir equation for the Ito model, which propagates as a traveling wave.

  11. Zero added oxygen for high quality sputtered ITO. A data science investigation of reduced Sn-content and added Zr

    SciTech Connect

    Peshek, Timothy J.; Burst, James M.; Coutts, Timothy J.; Gessert, Timothy A.

    2016-01-19

    Here, we demonstrate mobilities of >45 cm2/V s for sputtered tin-doped indium oxide (ITO) films at zero added oxygen. All films were deposited with 5 wt. % SnO2, instead of the more conventional 8–10 wt. %, and had varying ZrO2 content from 0 to 3 wt. %, with a subsequent reduction in In2O3 content. Moreover, these films were deposited by radio-frequency magnetron sputtering from nominally stoichiometric targets with varying oxygen partial pressure in the sputter ambient. Anomalous behavior was discovered for films with no Zr-added, where a bimodality of high and low mobilities was discovered for nominally similar growth conditions. However, all films showed the lowest resistivity and highest mobilities when the oxygen partial pressure in the sputter ambient was zero. This result is contrasted with several other reports of ITO transport performance having a maximum for small but nonzero oxygen partial pressure. Our result is attributed to the reduced concentration of SnO2. The addition of ZrO2 yielded the highest mobilities at >55 cm2/V s and the films showed a modest increase in optical transmission with increasing Zr-content.

  12. Zero added oxygen for high quality sputtered ITO. A data science investigation of reduced Sn-content and added Zr

    DOE PAGES

    Peshek, Timothy J.; Burst, James M.; Coutts, Timothy J.; ...

    2016-01-19

    Here, we demonstrate mobilities of >45 cm2/V s for sputtered tin-doped indium oxide (ITO) films at zero added oxygen. All films were deposited with 5 wt. % SnO2, instead of the more conventional 8–10 wt. %, and had varying ZrO2 content from 0 to 3 wt. %, with a subsequent reduction in In2O3 content. Moreover, these films were deposited by radio-frequency magnetron sputtering from nominally stoichiometric targets with varying oxygen partial pressure in the sputter ambient. Anomalous behavior was discovered for films with no Zr-added, where a bimodality of high and low mobilities was discovered for nominally similar growth conditions.more » However, all films showed the lowest resistivity and highest mobilities when the oxygen partial pressure in the sputter ambient was zero. This result is contrasted with several other reports of ITO transport performance having a maximum for small but nonzero oxygen partial pressure. Our result is attributed to the reduced concentration of SnO2. The addition of ZrO2 yielded the highest mobilities at >55 cm2/V s and the films showed a modest increase in optical transmission with increasing Zr-content.« less

  13. Femtosecond laser-induced modification at aluminum/diamond interface

    NASA Astrophysics Data System (ADS)

    Okada, Tatsuya; Tomita, Takuro; Ueki, Tomoyuki; Masai, Yuki; Bando, Yota; Tanaka, Yasuhiro

    2017-02-01

    We investigated femtosecond-laser-induced modification at an Al/diamond interface. The interface was irradiated from the backside through the diamond substrate, which is transparent to the laser beam. Extremely high pulse energies, i.e., 200 and 100 µJ/pulse, were used to irradiate the interface. The cross-section of the laser-irradiated line was observed with conventional and high-voltage transmission electron microscopy. The modification of the laser-irradiated interface was characterized by the formation of an amorphous phase sandwiched between the deformed Al film and the diamond substrate. The major chemical component of the amorphous phase was identified as carbon, blown from the diamond substrate. The newly formed interface between the amorphous phase and the diamond substrate was concave. In addition, a fine ripple structure with an average spacing one-quarter the wavelength of the laser light was formed only in the sample irradiated by the higher-energy pulses.

  14. Modification of nanostructured fused silica for use as superhydrophobic, IR-transmissive, anti-reflective surfaces

    NASA Astrophysics Data System (ADS)

    Boyd, Darryl A.; Frantz, Jesse A.; Bayya, Shyam S.; Busse, Lynda E.; Kim, Woohong; Aggarwal, Ishwar; Poutous, Menelaos; Sanghera, Jasbinder S.

    2016-04-01

    In order to mimic and enhance the properties of moth eye-like materials, nanopatterned fused silica was chemically modified to produce self-cleaning substrates that have anti-reflective and infrared transmissive properties. The characteristics of these substrates were evaluated before and after chemical modification. Furthermore, their properties were compared to fused silica that was devoid of surface features. The chemical modification imparted superhydrophobic character to the substrates, as demonstrated by the average water contact angles which exceeded 170°. Finally, optical analysis of the substrates revealed that the infrared transmission capabilities of the fused silica substrates (nanopatterned to have moth eye on one side) were superior to those of the regular fused silica substrates within the visible and near-infrared region of the light spectrum, with transmission values of 95% versus 92%, respectively. The superior transmission properties of the fused silica moth eye were virtually unchanged following chemical modification.

  15. The Effect of the Oxygen Plasma Treatment for ITO and ZnO Nanorods on the Electroluminescence of ZnO Nanorod/MEH-PPV Heterostructure Devices

    NASA Astrophysics Data System (ADS)

    Zhao, Su-Ling; Wang, Yong-Sheng; Gao, Song; Yang, Yi-Fan; Xu, Zheng

    2013-03-01

    Series devices of ITO/ZnO/ZnO nanorods/MEH-PPV/Al have been fabricated. ITO and ZnO nanorods of some devices are treated by O2 plasma. The electroluminescence of different devices is detected under different biases. UV electroluminescence of ZnO nanorods at 380nm is observed in all the devices. The intensity of 380nm increases when both ITO and ZnO nanorods are treated. The turn-on voltage of the treated device is lower than that of the non-treated device, and the EL power is enhanced. When the thickness of MEH-PPV is sufficiently thin, only 380 nm electroluminescence, besides a weak defect emission at 760 nm, is detected. The enhancement mechanism of the electroluminescence of the treated devices is discussed.

  16. Gas sensing at the nanoscale: engineering SWCNT-ITO nano-heterojunctions for the selective detection of NH3 and NO2 target molecules

    NASA Astrophysics Data System (ADS)

    Rigoni, F.; Drera, G.; Pagliara, S.; Perghem, E.; Pintossi, C.; Goldoni, A.; Sangaletti, L.

    2017-01-01

    The gas response of single-wall carbon nanotubes (SWCNT) functionalized with indium tin oxide (ITO) nanoparticles (NP) has been studied at room temperature and an enhanced sensitivity to ammonia and nitrogen dioxide is demonstrated. The higher sensitivity in the functionalized sample is related to the creation of nano-heterojunctions at the interface between SWCNT bundles and ITO NP. Furthermore, the different response of the two devices upon NO2 exposure provides a way to enhance also the selectivity. This behavior is rationalized by considering a gas sensing mechanism based on the build-up of space-charge layers at the junctions. Finally, full recovery of the signal after exposure to NO2 is achieved by UV irradiation for the functionalized sample, where the ITO NP can play a role to hinder the poisoning effects on SWCNT due to NO2 chemisorption.

  17. In-orbit performance of the ITOS improved attitude control system with Hall generator brushless motor and earth-splitting technique

    NASA Technical Reports Server (NTRS)

    Peacock, W. M.

    1973-01-01

    The National Aeronautics and Space Administration (NASA), launched ITOS-D with an improved attitude control system. A Hall generator brushless dc torque motor replaced the brush dc torque motor on Tiros-M and ITOS-A. Two CO2 attitude horizon sensors and one mirror replaced the four wideband horizon sensors and two mirrors on ITOS-1 and NOAA-1. Redundant pitch-control electronic boxes containing additional electronic circuitry for earth-splitting and brushless motor electronics were used. A method of generating a spacecraft earth-facing side reference for comparison to the time occurrence of the earth-splitting pulse was used to automatically correct pitch-attitude error. A single rotating flywheel, supported by a single bearing, provided gyroscopic stability and the required momentum interchange to keep one side of the satellite facing the earth. Magnetic torquing against the earth's magnetic field eliminated the requirement for expendable propellants which would limit satellite life in orbit.

  18. Impedimetric Sensing Proprieties of ITO Electrodes Functionalized with PEDOT:PSS/Azo-Calix[4]Arene for the Detection of Al3+ Ions Under Light Excitation

    NASA Astrophysics Data System (ADS)

    Echabaane, M.; Rouis, A.; Mahjoub, M. A.; Bonnamour, I.; Ben Ouada, H.

    2017-01-01

    This study describes an investigation of the sensitivity of the azo-calix[4]arene/poly(3,4-ethylenedioxythiophene)/poly-(styrenesulfonate) (PEDOT:PSS) thin film deposited on the indium tin oxide (ITO) electrode surface toward aluminum ions (Al3+) under light excitation. Thin films were deposited by the spin-coating technique. Adhesion of these films to the ITO surface was highlighted by performing contact angle measurements. Then, interfaces of the azo-calix[4]arene/PEDOT:PSS thin film were characterized by impedance measurements using electrochemical impedance spectroscopy. Obtained impedance spectra were fitted using an equivalent circuit. Finally, evolutions of the different components of this circuit were studied. These evolutions show that the sensitivity of the azo-calix[4]arene/PEDOT:PSS/ITO electrode is remarkably improved under illumination.

  19. Gas sensing at the nanoscale: engineering SWCNT-ITO nano-heterojunctions for the selective detection of NH3 and NO2 target molecules.

    PubMed

    Rigoni, F; Drera, G; Pagliara, S; Perghem, E; Pintossi, C; Goldoni, A; Sangaletti, L

    2017-01-20

    The gas response of single-wall carbon nanotubes (SWCNT) functionalized with indium tin oxide (ITO) nanoparticles (NP) has been studied at room temperature and an enhanced sensitivity to ammonia and nitrogen dioxide is demonstrated. The higher sensitivity in the functionalized sample is related to the creation of nano-heterojunctions at the interface between SWCNT bundles and ITO NP. Furthermore, the different response of the two devices upon NO2 exposure provides a way to enhance also the selectivity. This behavior is rationalized by considering a gas sensing mechanism based on the build-up of space-charge layers at the junctions. Finally, full recovery of the signal after exposure to NO2 is achieved by UV irradiation for the functionalized sample, where the ITO NP can play a role to hinder the poisoning effects on SWCNT due to NO2 chemisorption.

  20. Melanoma arising in a nevus of Ito: novel genetic mutations and a review of the literature on cutaneous malignant transformation of dermal melanocytosis.

    PubMed

    Tse, Julie Y; Walls, Brooke E; Pomerantz, Hyemin; Yoon, Charles H; Buchbinder, Elizabeth I; Werchniak, Andrew E; Dong, Fei; Lian, Christine G; Granter, Scott R

    2016-01-01

    Dermal melanocytosis refers to a spectrum of benign melanocytic proliferations that includes Mongolian spot, nevus of Ota and nevus of Ito. These lesions most commonly occur in persons of Asian or African descent and are often present at birth or develop during childhood. Very rarely, dermal melanocytoses undergo malignant transformation. There have been only 13 reports in the literature of primary cutaneous melanoma arising in dermal melanocytoses. We report a case of a Chinese woman with melanoma arising in a congenital nevus of Ito. We performed targeted next-generation sequencing of the tumor which revealed mutations of GNAQ and BAP1, suggesting that alterations in these two genes led to malignant transformation of the nevus of Ito. We also provide a summary of reports in the literature regarding primary cutaneous melanoma arising in the context of dermal melanocytosis.

  1. Enzymatic modification of schizophyllan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An enzymatic method was developed for the progressive modification of the polysaccharide schizophyllan. Fungal strains Hypocrea nigricans NRRL 62555, Penicillium crustosum NRRL 62558, and Penicillium simplicissimum NRRL 62550 were previously identified as novel sources of ß-endoglucanase with specif...

  2. Engineering the interfaces of ITO@Cu2S nanowire arrays toward efficient and stable counter electrodes for quantum-dot-sensitized solar cells.

    PubMed

    Jiang, Yan; Zhang, Xing; Ge, Qian-Qing; Yu, Bin-Bin; Zou, Yu-Gang; Jiang, Wen-Jie; Hu, Jin-Song; Song, Wei-Guo; Wan, Li-Jun

    2014-09-10

    Among the issues that restrict the power conversion efficiency (PCE) of quantum-dot-sensitized solar cells (QDSSCs), insufficient catalytic activity and stability of counter electrodes (CEs) are critical but challenging ones. The state-of-the-art Cu/Cu2S CEs still suffer from mechanical instability and uncertainty due to the reaction of copper and electrolyte. Herein, ITO@Cu2S core-shell nanowire arrays were developed to fabricate CEs for QDSSCs, which have no such issues in Cu/Cu2S CEs. These nanowire arrays exhibited small charge transfer resistance and sheet resistance, and provided more active catalytic sites and easy accessibility for electrolyte due to the three-dimensional structure upon use as CEs. More interestingly, it was found that the interface of ITO/Cu2S significantly affected the performance of ITO@Cu2S nanowire array CEs. By varying synthetic methods, a series of ITO@Cu2S nanowire arrays were prepared to investigate the influence of ITO/Cu2S interface on their performance. The results showed that ITO@Cu2S nanowire array CEs with a continuous Cu2S nanocrystal shell fabricated via an improved cation exchange route exhibited excellent and thickness-dependent performance. The PCE of corresponding QDSSCs increased by 11.6 and 16.5% compared to that with the discrete Cu2S nanocrystal and the classic Cu/Cu2S CE, respectively, indicating its promising potential as a new type of CE for QDSSCs.

  3. Study of the morphology of ZnS thin films deposited on different substrates via chemical bath deposition.

    PubMed

    Gómez-Gutiérrez, Claudia M; Luque, P A; Castro-Beltran, A; Vilchis-Nestor, A R; Lugo-Medina, Eder; Carrillo-Castillo, A; Quevedo-Lopez, M A; Olivas, A

    2015-01-01

    In this work, the influence of substrate on the morphology of ZnS thin films by chemical bath deposition is studied. The materials used were zinc acetate, tri-sodium citrate, thiourea, and ammonium hydroxide/ammonium chloride solution. The growth of ZnS thin films on different substrates showed a large variation on the surface, presenting a poor growth on SiO2 and HfO2 substrates. The thin films on ITO substrate presented a uniform and compact growth without pinholes. The optical properties showed a transmittance of about 85% in the visible range of 300-800 nm with band gap of 3.7 eV.

  4. Human Rights and Behavior Modification

    ERIC Educational Resources Information Center

    Roos, Philip

    1974-01-01

    Criticisms of behavior modification, which charge that it violates ethical and legal principles, are discussed and reasons are presented to explain behavior modification's susceptibility to attack. (GW)

  5. Doping effect on SILAR synthesized crystalline nanostructured Cu-doped ZnO thin films grown on indium tin oxide (ITO) coated glass substrates and its characterization

    NASA Astrophysics Data System (ADS)

    Dhaygude, H. D.; Shinde, S. K.; Velhal, Ninad B.; Takale, M. V.; Fulari, V. J.

    2016-08-01

    In the present study, a novel chemical route is used to synthesize the undoped and Cu-doped ZnO thin films in aqueous solution by successive ionic layer adsorption and reaction (SILAR) method. The synthesized thin films are characterized by x-ray diffractometer (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray analysis (EDAX), contact angle goniometer and UV-Vis spectroscopic techniques. XRD study shows that the prepared films are polycrystalline in nature with hexagonal crystal structure. The change in morphology for different doping is observed in the studies of FE-SEM. EDAX spectrum shows that the thin films consist of zinc, copper and oxygen elements. Contact angle goniometer is used to measure the contact angle between a liquid and a solid interface and after detection, the nature of the films is initiated from hydrophobic to hydrophilic. The optical band gap energy for direct allowed transition ranging between 1.60-2.91 eV is observed.

  6. Substrate dependent structural, optical and electrical properties of ZnS thin films grown by RF sputtering

    NASA Astrophysics Data System (ADS)

    Pathak, Trilok K.; Kumar, Vinod; Purohit, L. P.; Swart, H. C.; Kroon, R. E.

    2016-10-01

    Zinc sulphide (ZnS) films are of great importance for applications in various optoelectronic devices. ZnS thin films were grown on glass, indium tin oxide (ITO) and Corning glass substrates by radio-frequency magnetron sputtering at a temperature of 373 K and a comparative study of the structural, optical and electrical properties was performed using X-ray diffraction (XRD), scanning electron microscopy, optical and current-voltage (I-V) measurements. The XRD patterns showed that the sputtered thin films exhibited good crystallinity with the (111) peak around 2θ=28.3° indicating preferential orientation of the cubic structure. The maximum strain and most densely packed grains were obtained for the Corning glass substrate. The transmittance spectra of the films were measured in the wavelength range from 200 to 800 nm, showing that the films are about 77% transparent in the visible region. A slight change of 3.50 eV to 3.54 eV was found for the bandgap of the films deposited on different substrates. The ZnS thin films deposited on Corning glass show better crystallinity, morphology and I-V characteristics than that deposited on ordinary glass and ITO substrates.

  7. Effect of platinum-nanodendrite modification on the glucose-sensing properties of a zinc-oxide-nanorod electrode

    NASA Astrophysics Data System (ADS)

    Abdul Razak, Khairunisak; Neoh, Soo Huan; Ridhuan, N. S.; Mohamad Nor, Noorhashimah

    2016-09-01

    The properties of ZnO nanorods (ZnONRs) decorated with platinum nanodendrites (PtNDs) were studied. Various sizes of PtNDs were synthesized and spin coated onto ZnONRs, which were grown on indium-titanium-oxide (ITO) substrates through a low-temperature hydrothermal method. Scanning electron microscopy and X-ray diffraction analyses were conducted to analyze the morphology and structural properties of the electrodes. The effects of PtND size, glucose concentration, and Nafion amount on glucose-sensing properties were investigated. The glucose-sensing properties of electrodes with immobilized glucose oxidase (GOx) were measured using cyclic voltammetry. The bio-electrochemical properties of Nafion/GOx/42 nm PtNDs/ZnONRs/ITO glucose sensor was observed with linear range within 1-18 mM, with a sensitivity value of 5.85 μA/mM and a limit of detection of 1.56 mM. The results of this study indicate that PtNDs/ZnONRs/ITO has potential in glucose sensor applications.

  8. Hybrid Silver Mesh Electrode for ITO-Free Flexible Polymer Solar Cells with Good Mechanical Stability.

    PubMed

    Kim, Wanjung; Kim, Soyeon; Kang, Iljoong; Jung, Myung Sun; Kim, Sung June; Kim, Jung Kyu; Cho, Sung Min; Kim, Jung-Hyun; Park, Jong Hyeok

    2016-05-10

    Herein, we report a tailored Ag mesh electrode coated with poly(3,4-ethylenedioxythiophene) (PEDOT) polymer on a flexible polyethylene terephthalate (PET) substrate. The introduction of this highly conductive polymer solves the existing problems of Ag mesh-type transparent conductive electrodes, such as high pitch, roughness, current inhomogeneity, and adhesion problems between the Ag mesh grid and PEDOT polymer or PET substrate, to result in excellent electron spreading from the discrete Ag mesh onto the entire surface without sacrificing sheet conductivity and optical transparency. Based on this hybrid anode, we demonstrate highly efficient flexible polymer solar cells (PSCs) with a high fill factor of 67.11 %, which results in a power conversion efficiency (PCE) of 6.9 % based on a poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b'] dithiophene-2,6-diyl}{3-fluoro-2-[(2-ethylhexyl) carbonyl]thieno[3,4-b]thiophenediyl}):[6,6]-phenyl-C71 -butyric acid methyl ester bulk heterojunction device. Furthermore, the PSC device with the Ag mesh electrode also exhibits a good mechanical bending stability, as indicated by a 70 % retention of the initial PCE after 500 bending cycles compared with the PSC device with a PET/indium tin oxide electrode, which retained 0 % of the initial PCE after 300 bending cycles.

  9. THz behavior of indium-tin-oxide films on p-Si substrates

    SciTech Connect

    Brown, E. R. Zhang, W-D.; Chen, H.; Mearini, G. T.

    2015-08-31

    This paper reports broadband THz free-space transmission measurements and modeling of indium-tin-oxide (ITO) thin films on p-doped Si substrates. Two such samples having ITO thickness of 50 and 100 nm, and DC sheet conductance 260 and 56 Ω/sq, respectively, were characterized between 0.2 and 1.2 THz using a frequency-domain spectrometer. The 50-nm-film sample displayed very flat transmittance over the 1-THz bandwidth, suggesting it is close to the critical THz sheet conductance that suppresses multi-pass interference in the substrate. An accurate transmission-line-based equivalent circuit is developed to explain the effect, and then used to show that the net reflectivity and absorptivity necessarily oscillate with frequency. This has important implications for the use of thin-film metallic coupling layers on THz components and devices, such as detectors and sources. Consistent with previous reported results, the sheet conductance that best fits the THz transmittance data is roughly 50% higher than the DC values for both samples.

  10. Biofuel cell operating on activated THP-1 cells: A fuel and substrate study.

    PubMed

    Javor, Kristina; Tisserant, Jean-Nicolas; Stemmer, Andreas

    2017-01-15

    It is known that electrochemical energy can be harvested from mammalian cells, more specifically from white blood cells (WBC). This study focuses on an improved biofuel cell operating on phorbol myristate acetate (PMA) activated THP-1 human monocytic cells. Electrochemical investigation showed strong evidence pointing towards hydrogen peroxide being the primary current source, confirming that the current originates from NADPH oxidase activity. Moreover, an adequate substrate for differentiation and activation of THP-1 cells was examined. ITO, gold, platinum and glass were tested and the amount of superoxide anion produced by NADPH oxidase was measured by spectrophotometry through WST-1 reduction at 450nm and used as an indicator of cellular activity and viability. These substrates were subsequently used in a conventional two-compartment biofuel cell where the power density output was recorded. The material showing the highest cell activity compared to the reference cell culture plate and the highest power output was ITO. Under our experimental conditions, a power density of 4.5μW/cm(2) was reached. To the best of our knowledge, this is a threefold higher power output than other leukocyte biofuel cells.

  11. Quantum Dot Light Enhancement Substrate for OLED Solid-State Lighting

    SciTech Connect

    James Perkins; Matthew Stevenson; Gagan Mahan; Seth Coe-Sullivan; Peter Kazlas

    2011-01-21

    With DOE Award No. DE-EE00000628, QD Vision developed and demonstrated a cost-competitive solution for increasing the light extraction efficiency of OLEDs with efficient and stable color rendering index (CRI) for solid state lighting (SSL). Solution processable quantum dot (QD) films were integrated into OLED ITO-glass substrates to generate tunable white emission from blue emitting OLED) devices as well as outcouple light from the ITO film. This QD light-enhancement substrate (QD-LED) technology demonstrated a 60% increase in OLED forward light out-coupling, a value which increases to 76% when considering total increase in multi-directional light output. The objective for the first year was an 80% increase in light output. This project seeks to develop and demonstrate a cost-competitive solution for realizing increased extraction efficiency organic light emitting devices (OLEDs) with efficient and stable color rendering index (CRI) for SSL. Solution processible quantum dot (QD) films will be utilized to generate tunable white emission from blue emitting phosphorescent OLED (Ph-OLED) devices.

  12. Fabrication of 380 nm ultra violet light emitting diodes on nano-patterned n-type GaN substrate.

    PubMed

    Baek, Kwang Sun; Sadasivam, Karthikeyan Giri; Lee, Young Gon; Song, Young Ho; Jeong, Tak; Kim, Seung Hwan; Kim, Jae Kwan; Kim, Seung Hwan; Jeon, Seong-Ran; Lee, June Key

    2011-08-01

    380 nm ultraviolet (UV) light emitting diodes (LEDs) were grown on patterned n-type GaN substrate (PNS) with silicon dioxide (SiO2) nano pattern to improve the light output efficiency. Wet etched self assembled indium tin oxide (ITO) nano clusters serves as dry etching mask for converting the SiO2 layer grown on n-GaN template into SiO2 nano patterns by inductively coupled plasma etching. Three different diameter of ITO such as 200, 250 and 300 nm were used for SiO2 nano pattern fabrication. PNS is obtained by n-GaN regrowth on SiO2 nano patterns and UV LEDs were grown on PNS template by MOCVD. Enhanced light output intensity was observed by employing SiO2 nano patterns on n-GaN. Among different PNS UV LEDs, LED grown on PNS with 300 nm ITO diameter showed enhancement in light output intensity by 2.1 times compared to the reference LED without PNS.

  13. Readers of PCNA modifications.

    PubMed

    Ulrich, Helle D; Takahashi, Tomio

    2013-08-01

    The eukaryotic sliding clamp, proliferating cell nuclear antigen (PCNA), acts as a central coordinator of DNA transactions by providing a multivalent interaction surface for factors involved in DNA replication, repair, chromatin dynamics and cell cycle regulation. Posttranslational modifications (PTMs), such as mono- and polyubiquitylation, sumoylation, phosphorylation and acetylation, further expand the repertoire of PCNA's binding partners. These modifications affect PCNA's activity in the bypass of lesions during DNA replication, the regulation of alternative damage processing pathways such as homologous recombination and DNA interstrand cross-link repair, or impact on the stability of PCNA itself. In this review, we summarise our current knowledge about how the PTMs are "read" by downstream effector proteins that mediate the appropriate action. Given the variety of interaction partners responding to PCNA's modified forms, the ensemble of PCNA modifications serves as an instructive model for the study of biological signalling through PTMs in general.

  14. Temperature dependent electrical properties of Al/Cd0.8Zn0.2S/ITO Schottky diode

    NASA Astrophysics Data System (ADS)

    M, Parameshwari P.; V, Shrisha B.; Naik, K. Gopalakrishna

    2015-06-01

    In this work effect of temperature on the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of Al/Cd0.8Zn0.2S/ITO diode were studied. The series resistance, Schottky barrier height and ideality factor of the diode were obtained from the forward I-V characteristics at temperatures ranging193 K - 303 K. Activation energy of the diode was calculated from the reverse bias I-V characteristics. Room temperature C - V measurement was used to find the carrier concentration (NA) and built in voltage (Vb) of the diode. Schottky barrier height (ΦB) was also measured from C-V characteristics at room temperature.

  15. Synthesis and characterization of GaN thin films deposited on different substrates using a low-cost electrochemical deposition technique

    SciTech Connect

    Al-Heuseen, K.; Hashim, M. R.

    2012-09-06

    Gallium nitride GaN thin films were deposited on three different substrates; Si (111), Si (100) and ITO coated glass using electrochemical deposition technique at 20 Degree-Sign C. A mixture of gallium nitrate, ammonium nitrate was used as electrolyte. The deposited films were investigated at room temperature by a series of material characterization techniques, namely; scanning electron microscopy (SEM), EDX and X-ray diffraction (XRD). SEM images and EDX results indicated that the growth of GaN films varies according to the substrates. XRD analyses showed the presence of hexagonal wurtzite and cubic zinc blende GaN phases with the crystallite size around 18-29 nm.

  16. Programming for articularion modification.

    PubMed

    Gerber, A

    1977-02-01

    Within the past decade, principles and techniques of programmed instruction have been applied to the procedures of articulation modification in a number of preconstructed programs. The analysis of nine of these programs reveals that the majority of them are characterized by precisely stated objectives, ordered sequences of materials and procedures, clearly established criteria and rigorously controlled methods of reinforcement and recording of responses. Evaluation of the preconstructed programs raises some questions about the appropriateness of certain aspects of the technology to the process of articulation modification.

  17. Applications of Cu{sub 2}O octahedral particles on ITO glass in photocatalytic degradation of dye pollutants under a halogen tungsten lamp

    SciTech Connect

    Zhai, Wei; Sun, Fengqiang; Chen, Wei; Zhang, Lihe; Min, Zhilin; Li, Weishan

    2013-11-15

    Graphical abstract: - Highlights: • Photocatalytic activity of Cu{sub 2}O octahedral microcrystals on ITO glass was studied. • They showed high abilities in degradation of methylene blue in the presence of H{sub 2}O{sub 2}. • H{sub 2}O{sub 2} amount could affect the degradation efficiency. • Such particles could be easily recycled and still kept high activity. • Many dye pollutants and their mixtures could be efficiently degraded. - Abstract: Cu{sub 2}O octahedral microcrystals were prepared on the ITO glass by galvanostatic electrodeposition in CuSO{sub 4} solution with poly(vinylpryrrolidone) as the surfactant. By controlling the electrodeposition time, the microcrystals could be randomly distributed on the ITO glass and separated from each other, resulting in as many as possible (1 1 1) crystalline planes were exposed. Such microcrystals immobilized on ITO glass were employed in photodegradation of dye pollutants in the presence of H{sub 2}O{sub 2} under a 150 W halogen tungsten lamp. The photodegradation of methylene blue was taken as an example to evaluate the photocatalytic activities of the octahedral Cu{sub 2}O microcrystals. Effects of electrodeposition time and H{sub 2}O{sub 2} amount on the degradation efficiency was discussed, giving the optimum conditions and the corresponding degradation mechanism. The catalyst showed high ability in degradation of methylene blue, methyl orange, rhodamine B, eosin B and their mixtures under identical conditions.

  18. Application of indium tin oxide (ITO) thin film as a low emissivity film on Ni-based alloy at high temperature

    NASA Astrophysics Data System (ADS)

    Sun, Kewei; Zhou, Wancheng; Tang, Xiufeng; Luo, Fa

    2016-09-01

    Indium tin oxide (ITO) films as the low emissivity coatings of Ni-based alloy at high temperature were studies. ITO films were deposited on the polished surface of alloy K424 by direct current magnetron sputtering. These ITO-coated samples were heat-treated in air at 600-900 °C for 150 h to explore the effect of high temperature environment on the emissivity. The samples were analyzed by X-ray diffraction (XRD), SEM and EDS. The results show that the surface of sample is integrity after heat processing at 700 °C and below it. A small amount of fine crack is observed on the surface of sample heated at 800 °C and Ti oxide appears. There are lots of fine cracks on the sample annealed at 900 °C and a large number of various oxides are detected. The average infrared emissivities at 3-5 μm and 8-14 μm wavebands were tested by an infrared emissivity measurement instrument. The results show the emissivity of the sample after annealed at 600 and 700 °C is still kept at a low value as the sample before annealed. The ITO film can be used as a low emissivity coating of super alloy K424 up to 700 °C.

  19. Sequential changes of extracellular matrix and proliferation of Ito cells with enhanced expression of desmin and actin in focal hepatic injury.

    PubMed Central

    Ogawa, K.; Suzuki, J.; Mukai, H.; Mori, M.

    1986-01-01

    Immunohistochemical investigations were carried out on the properties of the cells and extracellular matrix (ECM) in focal hepatic injuries. A liquid nitrogen-cooled syringe needle was thrust into the rat liver. Necrotic areas became permeated with plasma within 24-hour period. Areas became strongly positive for fibronectin and were infiltrated with inflammatory cells positive for lysozyme. By the third day, Ito cells were proliferated in the peripheral portions of the damaged areas. These Ito cells showed enhanced immunostaining for desmin and actin but were negative for lysozyme. Interstitial fibers which were immunochemically positive for Types I and IV collagens, laminin, and fibronectin, began to increase from Day 3. They appeared on the rim of the hepatocytes adjacent to the damaged areas and extended into the injured regions with the Ito cells. An increase in basal laminas associated with capillaries and bile ducts also increased with a 1-day delay. The damaged areas were replaced by granulation tissue by Day 5. A rapid diminution then occurred in the granulation tissue, and normal hepatic tissue was restored in 7-10 days. These observations demonstrate that ECM changed in a sequential manner and then finally disappeared from the damaged site within 10 days. Although various cells, including parenchymal cells, macrophages, endothelial cells, and cholangiolar cells contributed to the healing of the damaged area, Ito cells, which exhibit unique phenotypic changes, presumably had a major role in the process. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 PMID:3799820

  20. Method and apparatus for laser/plasma chemical processing of substrates

    DOEpatents

    Gee, J.M.; Hargis, P.J. Jr.

    1984-07-21

    A process for the modification of substrate surfaces is described, wherein etching or deposition at a surface occurs only in the presence of both reactive species and a directed beam of coherent light.

  1. Instructional Improvement: Behavior Modification.

    ERIC Educational Resources Information Center

    Haring, Norris G.; Hayden, Alice H.

    Sixteen papers are provided. B. F. Skinner discusses the arrangement of contingencies for learning: Lloyd Homme describes behavioral engineering; and Frank Hewett considers behavior modification in special education. Also treated are experimental education by Norris Haring, program evaluation by Arthur Lumsdaine, and administration of special…

  2. Behavior Modification with Children

    ERIC Educational Resources Information Center

    Brown, Daniel G.

    1972-01-01

    The author urges wider use of positive reinforcement theories in helping emotionally disturbed and mentally handicapped children. Underlining the influence of environment on behavior, he also notes that behavior modification programs utilize fewer trained personnel more effectively and, like Tennessee's Re-Education Treatment, allow for therapy in…

  3. THE MODIFICATION OF STUTTERING.

    ERIC Educational Resources Information Center

    BRUTTEN, EUGENE J.; SHOEMAKER, DONALD J.

    INTENDED FOR BOTH THE COLLEGE STUDENT AND THE PROFESSIONAL SPEECH PATHOLOGIST, THE BOOK PRESENTS CURRENT LEARNING THEORIES CONCERNING STUTTERING, DATA IMPORTANT TO THE THEORIES, AND A 2-PROCESS THEORY OF LEARNING FOR THEORETICAL INTEGRATION OF THE DATA ON STUTTERING AND FOR THERAPEUTIC MODIFICATION. INFORMATION PRESENTED ABOUT BEHAVIORISTIC…

  4. Toy Modification Note. Revised.

    ERIC Educational Resources Information Center

    Vanderheiden, Gregg C.; And Others

    Described are toy modifications which enable handicapped individuals to operate battery-powered toys. A battery interrupter is explained as a device which fits between the batteries in a toy and provides the ability to have a separate on-off switch which can be custom designed to fit a handicapped user's needs. Construction and use of three types…

  5. Biblical behavior modification.

    PubMed

    Lasure, L C; Mikulas, W L

    1996-07-01

    Although we may have formalized and systematized the field of behavior modification in the last few decades, people around the world have been using behavioral change strategies throughout history. Premack's (1965) theory of reinforcement is often called "Grandma's rule" because grandmothers have long been using it (e.g. You must finish your vegetables before you may go out and play). Franks (1969, p. 4), in one of the first behavioral texts, gave historical examples from China, Turkey, France, and Italy. Knapp and Shodahl (1974) showed how Benjamin Franklin used behavior modification. And de Silva (1984, 1985) gave examples of behavior modification by the Buddha and other early Buddhists. Conspicuously absent from our literature are examples from the Judeo-Christian tradition. In this paper, we provide a number of behavior modification examples from the Bible (New International Version). Footnotes provide references for many more examples. In the discussion, we explore implications for education and therapy. Examples are grouped by the following categories: operant conditioning, respondent conditioning, modeling, and cognitive interventions. However, the Biblical examples, like contemporary case studies, do not always fall neatly into discrete categories. They often are a combination, particularly operant and respondent conditioning interweaving.

  6. Diet Modification for Hyperlipidemia

    PubMed Central

    Mann, Heather D.; Piotrowski, Pamela

    1992-01-01

    Hyperlipidemia is a major risk factor associated with cardiovascular disease. Dietary modification is effective in achieving and maintaining improved serum lipid levels. Nutritional care provided by a dietitian includes individual dietary and lifestyle assessment, formulating an appropriate dietary regimen, education, and follow-up assessments. PMID:21221406

  7. Surface morphology changes of graphene on flexible PET substrate upon thermal annealing.

    PubMed

    Samal, Monica; Lee, Jong Min; Park, Won Il; Yi, Dong Kee; Paik, Ungyu; Lee, Chang-Lyoul

    2011-11-01

    The performance of a polymer photovoltaic device using multilayered graphene on an amorphous PET substrate as the electrode was studied. The changes in surface morphology of graphene coated polyethylene terephthalate (PETG) substrate upon thermal annealing were investigated by atomic force microscopy (AFM), field emission scanning electron microscope (FE-SEM) and current-voltage characteristics. The root mean square (RMS) roughness of PETG substrate before annealing was 36.5 nm that decreased to 11.5 nm after 10 min thermal annealing at 110 degrees C. The mean grain size of the substrate decreased from 2301 nm2 to 848 nm2. The PETG surface became smooth when thermally annealed as the voids created by the bubbles in the graphene layer were filled up with thermal expansion of the PET substrate. However, cracks present initially on the graphene due to surface stress between the graphene and PET layer grew further upon annealing that deteriorated the device performance. This study on the graphene surface morphology change upon annealing and the consequent drop in device performance vis-à-vis an ITO glass electrode shows potential drawback of solar cell device fabrication on such flexible substrates.

  8. Light extraction efficiency enhancement of GaN-based blue LEDs based on ITO/ InxO ohmic contacts with microstructure formed by annealing in oxygen.

    PubMed

    Luo, Yi; Bai, Yiming; Han, Yanjun; Li, Hongtao; Wang, Lai; Wang, Jian; Sun, Changzheng; Hao, Zhibiao; Xiong, Bing

    2016-05-16

    Indium tin oxide (ITO)/ indium oxide (InxO) double layer structure was adopted as the transparent conduction and light scattering function layer to improve the light extraction efficiency of the GaN-based blue LEDs. The double layer structure was first deposited in one run by electron beam evaporation using ITO and Indium as the source respectively, and then annealed in an oxygen environment. This method can fabricate transparent electrode with microstructure and low specific contact resistivity one time free from lithography and etching, which makes the fabrication process simple and at a ower cost. For the 220 nm ITO/ 170 nm InxO double layer sample annealed at 600°C for 15 min in oxygen, measurement results show that its root mean square of roughness of the surface microstructure can be as high as 85.2 nm which introduces the strongest light scattering. Its light transmittance at 450 nm can maintain 92.4%. At the same time, it can realize lower specific contact resistivity with p-InGaN. Compared with the GaN-based blue LEDs with only 220 nm ITO electrode, the light output power of the LEDs with 220 nm ITO/ 170 nm InxO double layer structure can be increased about 58.8%, and working voltage at 20 mA injection current is decreased about 0.23 V due to the enhanced current spreading capability. The light output power improvement is also theoretically convinced by finite difference time domain simulations.

  9. Posttranslational protein modification in Archaea.

    PubMed

    Eichler, Jerry; Adams, Michael W W

    2005-09-01

    One of the first hurdles to be negotiated in the postgenomic era involves the description of the entire protein content of the cell, the proteome. Such efforts are presently complicated by the various posttranslational modifications that proteins can experience, including glycosylation, lipid attachment, phosphorylation, methylation, disulfide bond formation, and proteolytic cleavage. Whereas these and other posttranslational protein modifications have been well characterized in Eucarya and Bacteria, posttranslational modification in Archaea has received far less attention. Although archaeal proteins can undergo posttranslational modifications reminiscent of what their eucaryal and bacterial counterparts experience, examination of archaeal posttranslational modification often reveals aspects not previously observed in the other two domains of life. In some cases, posttranslational modification allows a protein to survive the extreme conditions often encountered by Archaea. The various posttranslational modifications experienced by archaeal proteins, the molecular steps leading to these modifications, and the role played by posttranslational modification in Archaea form the focus of this review.

  10. Posttranslational Protein Modification in Archaea

    PubMed Central

    Eichler, Jerry; Adams, Michael W. W.

    2005-01-01

    One of the first hurdles to be negotiated in the postgenomic era involves the description of the entire protein content of the cell, the proteome. Such efforts are presently complicated by the various posttranslational modifications that proteins can experience, including glycosylation, lipid attachment, phosphorylation, methylation, disulfide bond formation, and proteolytic cleavage. Whereas these and other posttranslational protein modifications have been well characterized in Eucarya and Bacteria, posttranslational modification in Archaea has received far less attention. Although archaeal proteins can undergo posttranslational modifications reminiscent of what their eucaryal and bacterial counterparts experience, examination of archaeal posttranslational modification often reveals aspects not previously observed in the other two domains of life. In some cases, posttranslational modification allows a protein to survive the extreme conditions often encountered by Archaea. The various posttranslational modifications experienced by archaeal proteins, the molecular steps leading to these modifications, and the role played by posttranslational modification in Archaea form the focus of this review. PMID:16148304

  11. Lightweight Substrates For Mirrors

    NASA Technical Reports Server (NTRS)

    Brown, D. Kyle

    1991-01-01

    New substrate uses conventional quasi-isotropic fabric laminate with surfacing layer of carbon-fiber paper consisting of randomly oriented chopped carbon fibers. Layered structure of fabric and paper relatively easy to manufacture. When impregnated with carbon, structure rigid and stable. Substrates of this type made quite thin, thus keeping areal weights to minimum. Mirrors of this type made faster, and cost less, than predecessors.

  12. The growth of urchin-like Co3O4 directly on sensor substrate and its gas sensing properties

    NASA Astrophysics Data System (ADS)

    Shen, Shui Fa; Xu, Mei Li; Lin, Dong Bao; Pan, Hai Bo

    2017-02-01

    Urchin-like Co3O4 has successfully grown directly on ITO glass and sensor ceramic substrate through hydrothermal reaction followed by calcination. The combined characterizations of X-ray diffraction (XRD) patterns, nitrogen adsorption-desorption and scanning electron microscopy (SEM) indicate that the as-prepared product possesses good crystallinity, large specific surface area and urchin-like morphology which is greatly influenced by the reaction additives. The sensor with urchin-like Co3O4 growing directly on ceramic sensor tube exhibits higher response sensitivity than the sensors fabricated with other morphological Co3O4 or by traditional coating method.

  13. Interfacial biocatalysis on charged and immobilized substrates: the roles of enzyme and substrate surface charge.

    PubMed

    Feller, Bob E; Kellis, James T; Cascão-Pereira, Luis G; Robertson, Channing R; Frank, Curtis W

    2011-01-04

    hypothesis, BSA substrates were chemically modified to reduce the magnitude of the negative charge at pH 8. Chemical modification was accomplished by the amidation of aspartic and glutamic acids to asparagine and glutamine. The ionic strength response of the chemically modified substrate was considerably different than that for the native BSA substrate at an identical pH, consistent with the trend based on substrate surface charge. Consequently, for substrates with a low net surface charge, the maximum achievable catalytic rate of the charge ladder was relatively independent of the solution ionic strength over the range examined; however, at high net substrate surface charge, the maximum rate showed a considerable ionic strength dependence.

  14. Gold nanonetwork film on the ITO surface exhibiting one-dimensional optical properties

    PubMed Central

    2012-01-01

    A network of gold nanostructures exhibiting one-dimensional gold nanostructure properties may become a prospective novel structure for optical, electrical and catalytic applications benefited by its unusual characteristics resulting from the collective properties of individual nanostructures in the network. In this paper, we demonstrate a facile method for the formation of high-density gold nanonetwork film on the substrate surface composed of quasi-1D nanoparticles (typically fusiform) with length ca. 10 nm - via reduction of gold ions in the presence of nanoseeds attached surface, binary surfactants of cetyltrimethylammonium bromide and hexamethyleneteramine and Ag+ ions. The length of the nanonetworks can be up to ca. 100 nm, which corresponds to the aspect ratio of ca. 10. The quasi-1D gold nanostructures as well as the nanonetworks were found to be sensitive to the binary surfactants system and the Ag+ ions as they can only be formed if all the chemicals are available in the reaction. The nanonetworks exhibit unique 1D optical properties with the presence of transverse and longitudinal surface plasmon resonance absorption. Owing to their peculiar structures that are composed of small quasi-1D nanoparticles, the nanonetworks may produce unusual optical and catalytic properties, which are potentially used in surface-enhanced Raman scattering, catalysis and optical and non-linear optical applications. PMID:22587640

  15. Crystallographic parameters and electro-optical constants in ITO thin films

    SciTech Connect

    Torkaman, N.M.; Ganjkhanlou, Y.; Kazemzad, M.; Dabaghi, H.H.; Keyanpour-Rad, M.

    2010-03-15

    Indium tin oxide thin films were deposited onto soda lime glass substrates using an e-beam evaporation system. In order to improve the structural, electrical and optical properties, the films were annealed at 450 deg. C and 500 deg. C in vacuum for 1 h. X-ray diffractions of samples were analyzed by Rietveld refinement and Warren-Averbach methods. By application of Levenberg-Marquardt least square method, the experimental transmittance data were fitted completely with the transmittance data calculated via a combination of modified Drude and Forouhi-Bloomer models. Focusing on the results, it was shown that the samples had a nanosize crystallite and enhancement of the annealing temperature resulted in an increase in the conductivity, carrier concentration, lattice parameter, crystallite size and micro-strain. However, it was found that the defects were preferentially accumulated along grain boundaries in sample annealed at lower temperature. Moreover, the finding revealed that conductivity of the samples was dominated by intra-grain in indium tin oxide films. Furthermore, increasing annealing temperature resulted in the orientation in < 111> crystal texture and also brought in an additional Burstein-Moss shift.

  16. Preparation of patterned graphene-ZnO hybrid nanoflower and nanorods on ITO surface

    SciTech Connect

    Tan, Sin Tee; Umar, Marjoni Imamora Ali; Ginting, Riski Titian; Yahaya, Muhammad; Yap, Chi Chin; Umar, Akrajas Ali; Salleh, Muhamad Mat; Majlis, Burhanuddin Yeop; Naumar, Fitri Yenni

    2013-11-27

    Hybrid ZnO nanostructure with controlled morphology have been proved to enhance the physical and chemical properties of the material and used as photodiode and sensor. In this paper, hybrid graphene-ZnO nanoflower and nanorods have been successfully synthesized via a seed mediated method with micropatterned ZnO nanoseed treated with multilayer graphene (MLG) in a hydrothermal process. In typical process, the ZnO nanoseeds with and without resists were spin coated with a multilayer graphene prior to the growth process. The treated seed was then used to grow the ZnO nanostructures in the growth solution that contained equimolar (0.04 M) of zinc nitrate hexahydrate and hexamethylenetetramine. The growth process was carried out inside an autoclave at temperature 70 °C. The growth time was 4 h. It was proved that the MLG treatment on micropatterning substrate may induce new morphology formation of ZnO nanostructure. It is expected that the heteroepitaxy reaction occurred between the MLG and ZnO interface. This presence method can be used as an alternative approach to control the morphology of hybrid ZnO nanostructure growth.

  17. Preparation of patterned graphene-ZnO hybrid nanoflower and nanorods on ITO surface

    NASA Astrophysics Data System (ADS)

    Tan, Sin Tee; Umar, Akrajas Ali; Umar, Marjoni Imamora Ali; Ginting, Riski Titian; Yahaya, Muhammad; Yap, Chi Chin; Salleh, Muhamad Mat; Majlis, Burhanuddin Yeop; Naumar, Fitri Yenni

    2013-11-01

    Hybrid ZnO nanostructure with controlled morphology have been proved to enhance the physical and chemical properties of the material and used as photodiode and sensor. In this paper, hybrid graphene-ZnO nanoflower and nanorods have been successfully synthesized via a seed mediated method with micropatterned ZnO nanoseed treated with multilayer graphene (MLG) in a hydrothermal process. In typical process, the ZnO nanoseeds with and without resists were spin coated with a multilayer graphene prior to the growth process. The treated seed was then used to grow the ZnO nanostructures in the growth solution that contained equimolar (0.04 M) of zinc nitrate hexahydrate and hexamethylenetetramine. The growth process was carried out inside an autoclave at temperature 70 °C. The growth time was 4 h. It was proved that the MLG treatment on micropatterning substrate may induce new morphology formation of ZnO nanostructure. It is expected that the heteroepitaxy reaction occurred between the MLG and ZnO interface. This presence method can be used as an alternative approach to control the morphology of hybrid ZnO nanostructure growth.

  18. Three-dimensional electrodes for dye-sensitized solar cells: synthesis of indium-tin-oxide nanowire arrays and ITO/TiO2 core-shell nanowire arrays by electrophoretic deposition.

    PubMed

    Wang, Hong-Wen; Ting, Chi-Feng; Hung, Miao-Ken; Chiou, Chwei-Huann; Liu, Ying-Ling; Liu, Zongwen; Ratinac, Kyle R; Ringer, Simon P

    2009-02-04

    Dye-sensitized solar cells (DSSCs) show promise as a cheaper alternative to silicon-based photovoltaics for specialized applications, provided conversion efficiency can be maximized and production costs minimized. This study demonstrates that arrays of nanowires can be formed by wet-chemical methods for use as three-dimensional (3D) electrodes in DSSCs, thereby improving photoelectric conversion efficiency. Two approaches were employed to create the arrays of ITO (indium-tin-oxide) nanowires or arrays of ITO/TiO(2) core-shell nanowires; both methods were based on electrophoretic deposition (EPD) within a polycarbonate template. The 3D electrodes for solar cells were constructed by using a doctor-blade for coating TiO(2) layers onto the ITO or ITO/TiO(2) nanowire arrays. A photoelectric conversion efficiency as high as 4.3% was achieved in the DSSCs made from ITO nanowires; this performance was better than that of ITO/TiO(2) core-shell nanowires or pristine TiO(2) films. Cyclic voltammetry confirmed that the reaction current was significantly enhanced when a 3D ITO-nanowire electrode was used. Better separation of charge carriers and improved charge transport, due to the enlarged interfacial area, are thought to be the major advantages of using 3D nanowire electrodes for the optimization of DSSCs.

  19. Pectin modifications: a review.

    PubMed

    Chen, Jun; Liu, Wei; Liu, Cheng-Mei; Li, Ti; Liang, Rui-Hong; Luo, Shun-Jing

    2015-01-01

    In recent years, the interest in studying modification of pectin has increased. A number of hydroxyl and carboxyl groups distributed along the backbone as well as a certain amount of neutral sugars presented as side chains make pectin capable of preparing a broad spectrum of derivatives. By forming pectin derivatives, their properties may be modified and some other new functional properties may be created. This article attempts to review the information about various methods used for pectin modification, including substitution (alkylation, amidation, quaternization, thiolation, sulfation, oxidation, etc.), chain elongation (cross-linking and grafting) and depolymerization (chemical, physical, and enzymatic degradation). Characteristics and applications of some pectin derivatives are also presented. In addition, the safety and regulatory status of pectin and its derivatives were reviewed.

  20. Response modification in carcinogenesis.

    PubMed Central

    Cerutti, P A

    1989-01-01

    A major goal in multistep carcinogenesis research is the integration of recent findings obtained by sophisticated molecular-genetic and cytogenetic analysis of cancer into the more descriptive concepts of experimental pathology. It is proposed that the creation of a promotable cell in carcinogenic initiation requires a response modification to extracellular or intercellular signals. Different types of response modification can be distinguished: changes in the receptors for growth and differentiation factors and their cytoplasmic and nuclear signal transduction pathways; increased resistance of initiated cells to cytotoxic agents; alterations in junctional cell-to-cell communications. The challenge of a response-modified cell to an appropriate promoter results in its selection and clonal expansion, usually to a benign tumor. In addition, for malignancy, chromosomal changes are required that affect cellular functions that can play a role early or late in tumorigenesis. These concepts are illustrated with examples from oncogene research and oxidant promotion. PMID:2667983

  1. Clinical risk modification.

    PubMed

    Wilson, J

    Claims for compensation in cases of clinical negligence have risen dramatically in recent years. The implementation of the NHS reforms, with greater clarity of roles and responsibilities and the emphasis on devolving decision-making as close to the patient as possible, is meant to affect the entire performance of healthcare delivery. For most senior managers and clinicians, the environment in which they operate has grown increasingly turbulent and complex. Both purchasers and providers of health care want the best and most effective and efficient care. The cost and quality of care are components in determining the value of health care delivered, and both are elements of healthcare risk. To begin to manage these elements of risk, the process of healthcare risk modification can be applied. Healthcare risk modification provides the best service for patients through obtaining a synergy between risk management, quality and the law.

  2. Monolayer Contact Doping from a Silicon Oxide Source Substrate.

    PubMed

    Ye, Liang; González-Campo, Arántzazu; Kudernac, Tibor; Núñez, Rosario; de Jong, Michel; van der Wiel, Wilfred G; Huskens, Jurriaan

    2017-04-03

    Monolayer contact doping (MLCD) is a modification of the monolayer doping (MLD) technique that involves monolayer formation of a dopant-containing adsorbate on a source substrate. This source substrate is subsequently brought into contact with the target substrate, upon which the dopant is driven into the target substrate by thermal annealing. Here, we report a modified MLCD process, in which we replace the commonly used Si source substrate by a thermally oxidized substrate with a 100 nm thick silicon oxide layer, functionalized with a monolayer of a dopant-containing silane. The thermal oxide potentially provides a better capping effect and effectively prevents the dopants from diffusing back into the source substrate. The use of easily accessible and processable silane monolayers provides access to a general and modifiable process for the introduction of dopants on the source substrate. As a proof of concept, a boron-rich carboranyl-alkoxysilane was used here to construct the monolayer that delivers the dopant, to boost the doping level in the target substrate. X-ray photoelectron spectroscopy (XPS) showed a successful grafting of the dopant adsorbate onto the SiO2 surface. The achieved doping levels after thermal annealing were similar to the doping levels acessible by MLD as demonstrated by secondary ion mass spectrometry measurements. The method shows good prospects, e.g. for use in the doping of Si nanostructures.

  3. Correlation of Cell and Substrate Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Setton, Tedhar; Levine, Joshua; Levine, Joseph; Guan, E.; Collazo, Lourdes; Ge, Shouren; Entcheva, Emilia; Rafailovich, Miriam

    2003-03-01

    The mechanical properties of neonatal rat ventricular fibroblasts plated onto elastomer surfaces were studied in vitro and correlated to the mechanical response of the substrate. In order to differentiate the response of the cells to mechanical as opposed to mechanical modifications in their environment, only the rheological properties of the substrates were modified. In the case of entangled polymers this can be accomplished either by varying the molecular weight or the thickness of polymer films spun cast onto rigid supports. Scanning lateral force microscopy, which has been shown to be an effective technique for measuring relative modulii of surfaces(1) was used to track the mechanical response of the substrates as a function of processing procedures, molecular weight, both in liquid, air, and following fibronectin incubation. The response of the living cells was then compared to that of the underlying substrate. The samples were then stained and the distribution of actin correlated to the mechanical response. 1. S. Ge et al. Phys. Rev. Lett. 11, (2000)2340

  4. Scalable cell alignment on optical media substrates.

    PubMed

    Anene-Nzelu, Chukwuemeka G; Choudhury, Deepak; Li, Huipeng; Fraiszudeen, Azmall; Peh, Kah-Yim; Toh, Yi-Chin; Ng, Sum Huan; Leo, Hwa Liang; Yu, Hanry

    2013-07-01

    Cell alignment by underlying topographical cues has been shown to affect important biological processes such as differentiation and functional maturation in vitro. However, the routine use of cell culture substrates with micro- or nano-topographies, such as grooves, is currently hampered by the high cost and specialized facilities required to produce these substrates. Here we present cost-effective commercially available optical media as substrates for aligning cells in culture. These optical media, including CD-R, DVD-R and optical grating, allow different cell types to attach and grow well on them. The physical dimension of the grooves in these optical media allowed cells to be aligned in confluent cell culture with maximal cell-cell interaction and these cell alignment affect the morphology and differentiation of cardiac (H9C2), skeletal muscle (C2C12) and neuronal (PC12) cell lines. The optical media is amenable to various chemical modifications with fibronectin, laminin and gelatin for culturing different cell types. These low-cost commercially available optical media can serve as scalable substrates for research or drug safety screening applications in industry scales.

  5. Interface modification for highly efficient organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Steim, Roland; Choulis, Stelios A.; Schilinsky, Pavel; Brabec, Christoph J.

    2008-03-01

    We present highly efficient inverted polymer:fullerene bulk-heterojunction solar cells by incorporation of a nanoscale organic interfacial layer between the indium tin oxide (ITO) and the metal oxide electron-conducting layer. We demonstrate that stacking of solution-processed organic and metal oxide interfacial layers gives highly charged selective low ohmic cathodes. The incorporation of a polyoxyethylene tridecyl ether interfacial layer between ITO and solution-processed titanium oxide (TiOx) raised the power conversion efficiency of inverted organic photovoltaics to 3.6%, an improvement of around 15% in their performance over comparable devices without the organic interfacial layer.

  6. Oxidative DNA modifications.

    PubMed

    Poulsen, Henrik E

    2005-07-01

    Oxidative DNA modifications are frequent in mammalian DNA and have been suggested an important mechanism in carcinogenesis, diabetes and ageing. The foundations for this suggestion are: Evidence for the importance of oxidative DNA modifications in cancer development is: high levels of oxidative lesions in cancer tissue; highly conserved and specific DNA repair systems targeting oxidative lesions; high levels of oxidative DNA lesions in oxidative DNA repair knock-out animals; defective repair of oxidative lesions in cancer-prone progeria syndromes; reduced cancer incidence in populations with high dietary antioxidant intake; and increased oxidative stress to DNA in tobacco smokers. Conflicting evidence for a relation between oxidative stress to DNA and cancer is: disagreement about the true levels and occurrence of the oxidative lesions in vivo; failure to identify the localization of oxidative lesions in important genes, e.g. tumor suppressor and oncogenes; lack of evidence that the oxidative lesions induce mutations in vivo; no cancer development in animals knocked-out for specific DNA repair enzymes in spite of high tissue levels of oxidative lesions; and unchanged cancer rates after antioxidant interventions in large clinical controlled and randomized trials. The rate of DNA oxidation has been estimated from urinary excretion of repair products and it is evident that if these lesions were not repaired, a large part of DNA would be oxidized to a degree not compatible with living. The methodologies by which oxidative DNA modifications are measured cover a wide and different range, advantages and disadvantages will be presented. One particular problem is artificial oxidation, and methods to prevent such artifacts will be presented together with results from a large interlaboratory standardization program. The methodology by which the lesions can be measured is complicated and prone to artifacts during DNA isolation, digestion, derivatization and maybe even during

  7. Bonded semiconductor substrate

    DOEpatents

    Atwater, Jr.; Harry A. , Zahler; James M.

    2010-07-13

    Ge/Si and other nonsilicon film heterostructures are formed by hydrogen-induced exfoliation of the Ge film which is wafer bonded to a cheaper substrate, such as Si. A thin, single-crystal layer of Ge is transferred to Si substrate. The bond at the interface of the Ge/Si heterostructures is covalent to ensure good thermal contact, mechanical strength, and to enable the formation of an ohmic contact between the Si substrate and Ge layers. To accomplish this type of bond, hydrophobic wafer bonding is used, because as the invention demonstrates the hydrogen-surface-terminating species that facilitate van der Waals bonding evolves at temperatures above 600.degree. C. into covalent bonding in hydrophobically bound Ge/Si layer transferred systems.

  8. CPLM: a database of protein lysine modifications

    PubMed Central

    Liu, Zexian; Wang, Yongbo; Gao, Tianshun; Pan, Zhicheng; Cheng, Han; Yang, Qing; Cheng, Zhongyi; Guo, Anyuan; Ren, Jian; Xue, Yu

    2014-01-01

    We reported an integrated database of Compendium of Protein Lysine Modifications (CPLM; http://cplm.biocuckoo.org) for protein lysine modifications (PLMs), which occur at active ε-amino groups of specific lysine residues in proteins and are critical for orchestrating various biological processes. The CPLM database was updated from our previously developed database of Compendium of Protein Lysine Acetylation (CPLA), which contained 7151 lysine acetylation sites in 3311 proteins. Here, we manually collected experimentally identified substrates and sites for 12 types of PLMs, including acetylation, ubiquitination, sumoylation, methylation, butyrylation, crotonylation, glycation, malonylation, phosphoglycerylation, propionylation, succinylation and pupylation. In total, the CPLM database contained 203 972 modification events on 189 919 modified lysines in 45 748 proteins for 122 species. With the dataset, we totally identified 76 types of co-occurrences of various PLMs on the same lysine residues, and the most abundant PLM crosstalk is between acetylation and ubiquitination. Up to 53.5% of acetylation and 33.1% of ubiquitination events co-occur at 10 746 lysine sites. Thus, the various PLM crosstalks suggested that a considerable proportion of lysines were competitively and dynamically regulated in a complicated manner. Taken together, the CPLM database can serve as a useful resource for further research of PLMs. PMID:24214993

  9. Biaxially textured composite substrates

    DOEpatents

    Groves, James R.; Foltyn, Stephen R.; Arendt, Paul N.

    2005-04-26

    An article including a substrate, a layer of a metal phosphate material such as an aluminum phosphate material upon the surface of the substrate, and a layer of an oriented cubic oxide material having a rock-salt-like structure upon the metal phosphate material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon a layer of a buffer material such as a SrTi.sub.x Ru.sub.1-x O.sub.3 layer.

  10. Genetic modification and genetic determinism.

    PubMed

    Resnik, David B; Vorhaus, Daniel B

    2006-06-26

    In this article we examine four objections to the genetic modification of human beings: the freedom argument, the giftedness argument, the authenticity argument, and the uniqueness argument. We then demonstrate that each of these arguments against genetic modification assumes a strong version of genetic determinism. Since these strong deterministic assumptions are false, the arguments against genetic modification, which assume and depend upon these assumptions, are therefore unsound. Serious discussion of the morality of genetic modification, and the development of sound science policy, should be driven by arguments that address the actual consequences of genetic modification for individuals and society, not by ones propped up by false or misleading biological assumptions.

  11. Genetic modification and genetic determinism

    PubMed Central

    Resnik, David B; Vorhaus, Daniel B

    2006-01-01

    In this article we examine four objections to the genetic modification of human beings: the freedom argument, the giftedness argument, the authenticity argument, and the uniqueness argument. We then demonstrate that each of these arguments against genetic modification assumes a strong version of genetic determinism. Since these strong deterministic assumptions are false, the arguments against genetic modification, which assume and depend upon these assumptions, are therefore unsound. Serious discussion of the morality of genetic modification, and the development of sound science policy, should be driven by arguments that address the actual consequences of genetic modification for individuals and society, not by ones propped up by false or misleading biological assumptions. PMID:16800884

  12. Electrochemical deposition and behavior of mixed-valent molybdenum oxide film at glassy carbon and ITO electrodes

    NASA Astrophysics Data System (ADS)

    Koçak, Süleyman; Ertaş, Fatma Nil; Dursun, Zekerya

    2013-01-01

    The effect of solution composition and the type of the anionic species on the electrochemical formation of mixed-valent molybdenum oxide on a glassy carbon and ITO electrode surfaces was elucidated. Susccessive recording of the voltammograms has shown that anionic species display different stabilizing effect on the reductive formation of hydrogen molybdenum bronzes [MoO3-x (OH)x] and chloroacetic acid buffer has given the best results. The deposit was built upon cycling the potential between 0 and -0.9 V (vs. Ag/AgCl) via reduction of Mo(VI) to Mo(V) on the electrode surface in pH 3.0 chloroacetic acid solution. Electrochemical impedance measurements carried out in this medium revealed a shift in potential zero charge values from -0.2 V to -0.55 V after the potential of the GCE had been cycled for 30 min. An establishment of mixed-valent molybdenum oxide deposit by time on the gold electrode surface was proved by quartz crystal microbalance measurements. Atomic force and scanning electron microscopy techniques were made use of so as to characterize the surface structures of the electrodes. X-ray photoelectron spectroscopy studies confirmed that the deposit contains both Mo(V) and Mo(VI). The deposited films exhibited unique catalytic activity towards nitrite oxidation consistent with the change in peak characteristics.

  13. A tris(8-hydroxyquinoline) aluminum-based organic bistable device using ITO surfaces modified by Ag nanoparticles

    NASA Astrophysics Data System (ADS)

    Jiao, Bo; Wu, Zhaoxin; Dong, Hua; Ning, Shuya; Hou, Xun

    2013-11-01

    A tris (8-hydroxyquinoline) aluminum (Alq3)-based organic bistable device (OBD) using Al electrode and ITO electrode modified by Ag nanoparticles (NPs) was reported. The OBD exhibits high ON/OFF switching ratios in the range of 102-103 and long retention time over 104 s. The influence of the Ag NPs densities, as well as the Alq3 film thickness on the switch performance current-voltage (I-V) of the OBDs was studied. Correlation between filament formation mechanism and charge storage mechanism was observed by analysing the I-V characteristics of OBDs with different Alq3 film thickness. As for the Alq3 film with thickness of 300 nm, the trapping effect of Ag NPs leads to both ON and OFF states for OBD; for 100 nm thick Alq3 film, the effect of filamentation dominates in the ON and OFF states of OBD. For the case of 200 nm thick Alq3 film, however, the ON state results from the filamentation effect, while trapping effect is responsible for the OFF state. In addition, the diffusion effect of Al atoms in Alq3 film in the devices was discussed and was expected to explain this thickness-dependence relationship.

  14. Electrochemical properties of core-shell TiC-TiO2 nanoparticle films immobilized at ITO electrode surfaces.

    PubMed

    Stott, Susan J; Mortimer, Roger J; Dann, Sandie E; Oyama, Munetaka; Marken, Frank

    2006-12-14

    Titanium carbide (TiC) nanoparticles are readily deposited onto tin-doped indium oxide (ITO) electrodes in the form of thin porous films. The nanoparticle deposits are electrically highly conducting and electrochemically active. In aqueous media (at pH 7) and at applied potentials positive of 0.3 V vs. SCE partial anodic surface oxidation and formation (at least in part) of novel core-shell TiC-TiO2 nanoparticles is observed. Significant thermal oxidation of TiC nanoparticles by heating in air occurs at a temperature of 250 degrees C and leads first to core-shell TiC-TiO2 nanoparticles, next at ca. 350 degrees C to TiO2 (anatase), and finally at temperatures higher than 750 degrees C to TiO2 (rutile). Electrochemically and thermally partially oxidized TiC nanoparticles still remain very active and for some redox systems electrocatalytically active. Scanning and transmission electron microscopy (SEM and TEM), temperature dependent XRD, quartz crystal microbalance, and voltammetric measurements are reported. The electrocatalytic properties of the core-shell TiC-TiO2 nanoparticulate films are surveyed for the oxidation of hydroquinone, ascorbic acid, and dopamine in aqueous buffer media. In TiC-TiO2 core-shell nanoparticle films TiO2 surface reactivity can be combined with TiC conductivity.

  15. Clarithromycin reduces Isus and Ito currents in human atrial myocytes with minor repercussions on action potential duration.

    PubMed

    Gluais, Pascale; Bastide, Michèle; Grandmougin, Daniel; Fayad, Georges; Adamantidis, Monique

    2003-12-01

    The macrolide antibacterial agent clarithromycin has been shown to cause QT interval prolongation on the electrocardiogram. In rabbit heart preparations clarithromycin (concentration dependently) lengthened the action potential duration and blocked the delayed rectifier current. The aim of the present study was to investigate the clarithromycin effects: (i) on the Ca2+ L-type and the main K+ repolarizing currents on human atrial myocytes, using whole-cell patch clamp recordings and (ii) on action potentials recorded from human atrial and ventricular myocardium using conventional microelectrodes. It has been found that (i) 10-30 microM clarithromycin reduced the sustained current Isus significantly and that a 100 microM concentration was needed to cause a significant reduction in the transient outward current Ito, whereas clarithomycin did not affect the calcium current and (ii) clarithromycin (10-100 microM) prolonged the action potential duration in atrial preparations but did not alter the different parameters of the ventricular action potential. It is concluded that clarithromycin exerts direct cardiac electrophysiological effects that may contribute to pro-arrythmic potential.

  16. Versatile MoS2 Nanosheets in ITO-Free and Semi-transparent Polymer Power-generating Glass

    PubMed Central

    Hu, Xiaotian; Chen, Lie; Tan, Licheng; Zhang, Yong; Hu, Lin; Xie, Bing; Chen, Yiwang

    2015-01-01

    Chemical exfoliated ultra-thin MoS2 nanosheets (NSs) with well 2D structure were demonstrated for interfacial layers and Ag nanowires composite transparent electrode in polymer solar cells (PSCs). The smooth and uniform n-type and p-type (after the plasma treatment) MoS2 NSs could improve fill factor of devices and light absorption in active layer. The optimized Ag nanowires–MoS2 NSs (AgNW-MoS2 NSs) transparent electrode presented a low sheet resistance of 9.8 Ω sq−1, and the corresponding transmittance also exhibited a high value of 93.1% at 550 nm. As a result, ITO-free PSCs based on AgNW-MoS2 NSs/n-MoS2 NSs cathode and p-MoS2 NSs/Ag anode achieved a highest PCE of 8.72%. Furthermore, a high efficiency (6.55%), large area and low cost semi-transparent power-generating glass was obtained, after reducing the thickness of top Ag electrode from 100 nm to 30 nm. To our best knowledge, it is the highest performance for semi-transparent PSCs devices reported up to now. The novel semi-transparent power-generating glass showed good performance and color purity for commercial applications in the near future. PMID:26177887

  17. Enhance the light-harvesting capability of the ITO-free inverted small molecule solar cell by ZnO nanorods.

    PubMed

    Lin, Ming-Yi; Wu, Shang-Hsuan; Hsiao, Li-Jen; Budiawan, Widhya; Boopathi, Karunakara Moorthy; Tu, Wei-Chen; Chang, Yia-Chung; Chu, Chih-Wei

    2016-08-08

    The ITO-free inverted SMPV1:PC71BM solar cells with an Al doped ZnO (AZO) transparent electrodes are fabricated. The AZO thin film prepared by pulsed laser deposition (PLD) technique exhibits high transmission (>85%) and low sheet resistance (~30 Ω/sq) and the power conversion efficiency (PCE) of devices based on AZO electrode can reach around 4%. To further enhance the light harvesting of the absorption layer of solar cells, ZnO nanorods interlayer is grown on the AZO layer before the deposition the active layer. The absorption spectrums of devices under various conditions are also simulated by RCWA method to identify the optical saturation length of the ZnO nanorods. The PCE of ITO-free inverted small molecule solar cell improved with ZnO nanorods can reach 6.6%.

  18. Dual modification of biomolecules.

    PubMed

    Maruani, Antoine; Richards, Daniel A; Chudasama, Vijay

    2016-07-14

    With the advent of novel bioorthogonal reactions and "click" chemistry, an increasing number of strategies for the single labelling of proteins and oligonucleotides have emerged. Whilst several methods exist for the site-selective introduction of a single chemical moiety, site-selective and bioorthogonal dual modification of biomolecules remains a challenge. The introduction of multiple modules enables a plethora of permutations and combinations and can generate a variety of bioconjuguates with many potential applications. From de novo approaches on oligomers to the post-translational functionalisation of proteins, this review will highlight the main strategies to dually modify biomolecules.

  19. Multiple alternative substrate kinetics.

    PubMed

    Anderson, Vernon E

    2015-11-01

    The specificity of enzymes for their respective substrates has been a focal point of enzyme kinetics since the initial characterization of metabolic chemistry. Various processes to quantify an enzyme's specificity using kinetics have been utilized over the decades. Fersht's definition of the ratio kcat/Km for two different substrates as the "specificity constant" (ref [7]), based on the premise that the important specificity existed when the substrates were competing in the same reaction, has become a consensus standard for enzymes obeying Michaelis-Menten kinetics. The expansion of the theory for the determination of the relative specificity constants for a very large number of competing substrates, e.g. those present in a combinatorial library, in a single reaction mixture has been developed in this contribution. The ratio of kcat/Km for isotopologs has also become a standard in mechanistic enzymology where kinetic isotope effects have been measured by the development of internal competition experiments with extreme precision. This contribution extends the theory of kinetic isotope effects to internal competition between three isotopologs present at non-tracer concentrations in the same reaction mix. This article is part of a special issue titled: Enzyme Transition States from Theory and Experiment.

  20. Enamides: valuable organic substrates.

    PubMed

    Carbery, David R

    2008-10-07

    Enamides display a fine balance of stability and reactivity, which is now leading to their increasing use in organic synthesis. Enamides offer multiple opportunities for the inclusion of nitrogen based functionality into organic systems. Recent examples of these compounds as substrates are discussed in this article.

  1. Generation of protein-derived redox cofactors by posttranslational modification.

    PubMed

    Davidson, Victor L

    2011-01-01

    Redox enzymes which catalyze the oxidation and reduction of substrates are ubiquitous in nature. These enzymes typically possess exogenous cofactors to allow them to perform catalytic functions which cannot be accomplished using only amino acid residues. It is now evident that nature also employs an alternative strategy of generating catalytic and redox-active sites in proteins by posttranslational modification of amino acid residues. This review describes the structures and functions of several of these protein-derived cofactors and the diverse mechanisms of posttranslational modification through which they are generated.

  2. Surface modification using ionic liquid ion beams

    NASA Astrophysics Data System (ADS)

    Takaoka, Gikan H.; Hamaguchi, Takuya; Takeuchi, Mitsuaki; Ryuto, Hiromichi

    2014-12-01

    We developed an ionic liquid (IL) ion source using 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) and produced IL ion beams by applying a high electric field between the tip and the extractor. Time-of-flight measurements showed that small cluster and fragment ions were contained in the positive and negative ion beams. The positive and negative cluster ions were deposited on Si(1 0 0) substrates. X-ray photoelectron spectroscopy measurements showed that the composition of the deposited layers was similar to that of an IL solvent. This suggests that a cation (A+) or an anion (B-) was attached to an IL cluster (AB)n, resulting in the formation of positive cluster ions (AB)nA+ or negative cluster ions (AB)nB-, respectively. The surfaces of the IL layers deposited on Si(1 0 0) substrates were flat at an atomic level for positive and negative cluster ion irradiation. Moreover, the contact angles of the deposited layers were similar to that of the IL solvent. Thus, surface modification of Si(1 0 0) substrates was successfully demonstrated with BMIM-PF6 cluster ion beams.

  3. The electrodeposition of multilayers on a polymeric substrate in Flexible Organic Light Emitting Diode (OLED)

    NASA Astrophysics Data System (ADS)

    Guedes, Andre F. S.; Guedes, Vilmar P.; Tartari, Simone; Cunha, Idaulo Jose

    2016-09-01

    The development of Organic Light Emitting Diode (OLED), using an optically transparent substrate material and organic semiconductor materials, has been widely utilized by the electronic industry when producing new technological products. The OLED are the base Poly(3,4-ethylenedioxythiophene), PEDOT, Poly(p-phenylenevinylene), PPV, and Polyaniline, PANI, were deposited in Indium Tin Oxide, ITO, and characterized by UV-Visible Spectroscopy (UV-Vis), Optical Parameters (OP) and Scanning Electron Microscopy (SEM). In addition, the thin film obtained by the deposition of PANI, prepared in perchloric acid solution, was identified through PANI-X1. The result obtained by UV-Vis has demonstrated that the PET/ITO/PEDOT/PPV/PANI-X1/Al layer does not have displacement of absorption for wavelengths greaters after spin-coating and electrodeposition. Thus, the spectral irradiance of the OLED informed the irradiance of 100 W/m2, and this result, compared with the standard Light Emitting Diode (LED), has indicated that the OLED has higher irradiance. After 1200 hours of electrical OLED tests, the appearance of nanoparticles visible for images by SEM, to the migration process of organic semiconductor materials, was present, then. Still, similar to the phenomenon of electromigration observed in connections and interconnections of microelectronic devices, the results have revealed a new mechanism of migration, which raises the passage of electric current in OLED.

  4. Effect of conductive substrate (working electrode) on the morphology of electrodeposited Cu2O

    NASA Astrophysics Data System (ADS)

    ELmezayyen, Ayman S.; Guan, Shian; Reicha, Fikry M.; El-Sherbiny, Ibrahim M.; Zheng, jianming; Xu, Chunye

    2015-05-01

    Cu2O thin films were electrodeposited from a Cu(II) acetate solution containing 0.02 M Copper(II) acetate (Cu(OAc)2) and 0.1 M sodium acetate (NaOAc) at pH 5.6, using three different working conductive electrodes with approximately the same square resistance -indium doped tin oxide glass (ITO/Glass), fluorine-doped tin oxide glass (FTO/Glass), and indium doped tin oxide polyethylene terephthalate (ITO/PET)—under identical conditions using a common growth condition. The Cu2O thin films were characterized by means of scanning electron microscopy, x-ray diffraction (XRD), current density versus growth time for Cu2O films, and electrochemical impedance spectroscopy. The results showed that the choice of substrate materials has a crucial role in controlling Cu2O growth. The charge transfer resistance (Rct) of FTO/Glass-Cu2O exhibits the lowest value; this means that FTO/Glass-Cu2O possess the highest electron transfer efficiency. All Cu2O films showed n-type semiconductor characteristic with charge carrier densities varying between 1.4 × 1018-1.2 × 1019 cm-3.

  5. Optically anisotropic substrates via wrinkle-assisted convective assembly of gold nanorods on macroscopic areas

    PubMed Central

    Tebbe, Moritz; Mayer, Martin; Glatz, Bernhard A.; Hanske, Christoph; Probst, Patrick T.; Müller, Mareen B.; Karg, Matthias; Chanana, Munish; König, Tobias A. F.; Kuttner, Christian

    2015-01-01

    We demonstrate the large-scale organisation of anisotropic nanoparticles into linear assemblies displaying optical anisotropy on macroscopic areas. Monodisperse gold nanorods with a hydrophilic protein shell are arranged by dip-coating on wrinkled surfaces and subsequently transferred to indium tin oxide (ITO) substrates by capillary transfer printing. We elucidate how tuning the wrinkle amplitude enables us to precisely adjust the assembly morphology and fabricate single, double and triple nanorod lines. For the single lines, we quantify the order parameter of the assemblies as well as interparticle distances from scanning electron microscopy (SEM) images. We find an order parameter of 0.97 and a mean interparticle gap size of 7 nm. This combination of close to perfect uni-axial alignment and close-packing gives rise to pronounced macroscopic anisotropic optical properties due to strong plasmonic coupling. We characterise the optical response of the assemblies on ITO-coated glass via UV/vis/NIR spectroscopy and determine an optical order parameter of 0.91. The assemblies are thus plasmonic metamaterials, as their periodicity and building block sizes are well below the optical wavelength. The presented approach does not rely on lithographic patterning and provides access to functional materials, which could have applications in subwavelength waveguiding, photovoltaics, and for large-area metamaterial fabrication. PMID:25951174

  6. Substrate system for spray forming

    DOEpatents

    Chu, Men G.; Chernicoff, William P.

    2002-01-01

    A substrate system for receiving a deposit of sprayed metal droplets including a movable outer substrate on which the sprayed metal droplets are deposited. The substrate system also includes an inner substrate disposed adjacent the outer substrate where the sprayed metal droplets are deposited on the outer substrate. The inner substrate includes zones of differing thermal conductivity to resist substrate layer porosity and to resist formation of large grains and coarse constituent particles in a bulk layer of the metal droplets which have accumulated on the outer substrate. A spray forming apparatus and associated method of spray forming a molten metal to form a metal product using the substrate system of the invention is also provided.

  7. Substrate system for spray forming

    DOEpatents

    Chu, Men G.; Chernicoff, William P.

    2000-01-01

    A substrate system for receiving a deposit of sprayed metal droplets including a movable outer substrate on which the sprayed metal droplets are deposited. The substrate system also includes an inner substrate disposed adjacent the outer substrate where the sprayed metal droplets are deposited on the outer substrate. The inner substrate includes zones of differing thermal conductivity to resist substrate layer porosity and to resist formation of large grains and coarse constituent particles in a bulk layer of the metal droplets which have accumulated on the outer substrate. A spray forming apparatus and associated method of spray forming a molten metal to form a metal product using the substrate system of the invention is also provided.

  8. Electrochemical and spectral studies of auto-assembled arrays of calix[4]arenequinhydrone charge-transfer complex on indium-tin oxide (ITO) glass.

    PubMed

    Youchret-Zallez, Oumayma Ben; Besbes-Hentati, Salma; Bouvet, Marcel; Said, Hechmi

    2014-01-01

    A sensing materiel based on calix[4]arene molecules is electrochemically deposited on ITO electrode coated. A brown film was electrodeposited at a potential Eimp = -1.00 V versus SCE in acetonitrile solvent, however in dichloromethane solvent, a bluish film auto-assembled on the ITO electrode coated at a potential Eimp = -0.65 V versus SCE. Both films are subsequently analyzed by cyclic voltammetry and UV-Vis spectroscopy. This investigation shows that in acetonitrile solvent, the charge-transfer complex, calix[4]arenequinhydrone was formed in electrolytic solution and it was not self-assembled on the ITO electrode. The related UV-Vis spectrum shows a single absorption band towards a wavelength about 350 nm. The optical behaviour of the blue film shows two absorption bands: the first one appears on the first absorption band of the acceptor at 305 nm and the second one in the visible range at 502 nm. The band situated in the visible range correspond to a well-defined charge-transfer band indicating the presence of the charge-transfer complex, the calix[4]arenequinhydrone.

  9. Very thin ITO/metal mesh hybrid films for a high-performance transparent conductive layer in GaN-based light-emitting diodes

    NASA Astrophysics Data System (ADS)

    Min, Jung-Hong; Kwak, Hoe-Min; Kim, Kiyoung; Jeong, Woo-Lim; Lee, Dong-Seon

    2017-01-01

    In this paper, we introduce very thin Indium tin oxide (ITO) layers (5, 10, and 15 nm) hybridized with a metal mesh to produce high-performance transparent conductive layers (TCLs) in near-ultraviolet light-emitting diodes (NUV LEDs). Using UV-vis-IR spectrometry, Hall measurement, and atomic force microscopy, we found that 10 nm was the optimal thickness for the very thin ITO layers in terms of outstanding transmittance and sheet resistance values as well as stable contact properties when hybridized with the metal mesh. The proposed layers showed a value of 4.56 Ω/□ for sheet resistance and a value of 89.1% for transmittance. Moreover, the NUV LEDs fabricated with the hybrid TCLs achieved ˜140% enhanced light output power compared to that of 150 nm thick ITO layers. Finally, to verify the practical usage of the TCLs for industrial applications, we packaged the NUV LED chips and obtained improved turn-on voltage (3.48 V) and light output power (˜116%) performance.

  10. Very thin ITO/metal mesh hybrid films for a high-performance transparent conductive layer in GaN-based light-emitting diodes.

    PubMed

    Min, Jung-Hong; Kwak, Hoe-Min; Kim, Kiyoung; Jeong, Woo-Lim; Lee, Dong-Seon

    2017-01-27

    In this paper, we introduce very thin Indium tin oxide (ITO) layers (5, 10, and 15 nm) hybridized with a metal mesh to produce high-performance transparent conductive layers (TCLs) in near-ultraviolet light-emitting diodes (NUV LEDs). Using UV-vis-IR spectrometry, Hall measurement, and atomic force microscopy, we found that 10 nm was the optimal thickness for the very thin ITO layers in terms of outstanding transmittance and sheet resistance values as well as stable contact properties when hybridized with the metal mesh. The proposed layers showed a value of 4.56 Ω/□ for sheet resistance and a value of 89.1% for transmittance. Moreover, the NUV LEDs fabricated with the hybrid TCLs achieved ∼140% enhanced light output power compared to that of 150 nm thick ITO layers. Finally, to verify the practical usage of the TCLs for industrial applications, we packaged the NUV LED chips and obtained improved turn-on voltage (3.48 V) and light output power (∼116%) performance.

  11. Assistance of partially reduced MoO3 interlayer to hole-injection at iron phthalocyanine/ITO interface evidenced by photoemission study

    NASA Astrophysics Data System (ADS)

    Liu, L. Y.; Wan, L.; Cao, L.; Han, Y. Y.; Zhang, W. H.; Chen, T. X.; Guo, P. P.; Wang, K.; Xu, F. Q.

    2013-04-01

    Molybdenum trioxide (MoO3) has been widely used as an interlayer between electrode and functional organic layer inducing significant improvement in the performance of organic electronic and optoelectronic devices such as organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs). In this work, the electronic structures and energy level alignment at FePc/MoO3 (3 nm)/ITO and FePc/MoOx (3 nm)/ITO (x < 3) interfaces have been comparatively investigated in situ by means of photoemission spectroscopy (PES) in an attempt to understand the influence of MoOx layer on the interfacial hole injection property. It is found that the electron injection barrier is only 0.45 eV for electron extraction from the highest occupied molecular orbital (HOMO) of FePc to the conduction band of MoOx. Simultaneously, two gap states at binding energy of 1.15 eV and 2.30 eV present in 3 nm MoOx, which extend from the valence band maximum of MoOx to the Fermi level. These gap states are suggested to originate from the partial occupation of Mo 4d states due to the reduction of MoO3 during the annealing process. Both lowered electron extraction barrier and presence of interfacial gap states appear to assist the hole injection from ITO anode into FePc by the insertion of MoOx layer.

  12. Thermal effects of the substrate on water droplet evaporation

    NASA Astrophysics Data System (ADS)

    Sobac, B.; Brutin, D.

    2012-08-01

    We experimentally investigate the behavior of a pinned water droplet evaporating into air. The influence of the substrate temperature and substrate thermal properties on the evaporation process are studied in both hydrophilic and hydrophobic conditions. Our objective is to understand the effect of thermal mechanisms on the droplet evaporation process. The experimental results are compared with the quasisteady, diffusion-driven evaporation model, which is implemented under the influence of the temperature; the model assumes the isothermia of the droplet at the substrate temperature. The results highlight a favorable correlation between the model and the experimental data at ambient temperatures for most situations considered here. The model works to qualitatively describe the influence of the substrate temperature on the evaporation process. However, with an increase in the substrate temperature, the role of the thermal-linked mechanisms becomes increasingly important; this experiment highlights the need for more accurate models to account for the buoyant convection in vapor transport and the evaporative cooling and heat conduction between the droplet and the substrate. Finally, the experimental data reveal the modification of contact angle evolution as the temperature increases and the crucial role played by the nature of the substrate in the evaporation of a sessile droplet. The influence of the substrate thermal properties on the global evaporation rate is explained by the parallel thermal effusivity of the liquid and solid phases.

  13. Multi-Substrate Terpene Synthases: Their Occurrence and Physiological Significance

    PubMed Central

    Pazouki, Leila; Niinemets, Ülo

    2016-01-01

    Terpene synthases are responsible for synthesis of a large number of terpenes in plants using substrates provided by two distinct metabolic pathways, the mevalonate-dependent pathway that is located in cytosol and has been suggested to be responsible for synthesis of sesquiterpenes (C15), and 2-C-methyl-D-erythritol-4-phosphate pathway located in plastids and suggested to be responsible for the synthesis of hemi- (C5), mono- (C10), and diterpenes (C20). Recent advances in characterization of genes and enzymes responsible for substrate and end product biosynthesis as well as efforts in metabolic engineering have demonstrated existence of a number of multi-substrate terpene synthases. This review summarizes the progress in the characterization of such multi-substrate terpene synthases and suggests that the presence of multi-substrate use might have been significantly underestimated. Multi-substrate use could lead to important changes in terpene product profiles upon substrate profile changes under perturbation of metabolism in stressed plants as well as under certain developmental stages. We therefore argue that multi-substrate use can be significant under physiological conditions and can result in complicate modifications in terpene profiles. PMID:27462341

  14. Soviet ionospheric modification research

    SciTech Connect

    Duncan, L.M.; Carlson, H.C.; Djuth, F.T.; Fejer, J.A.; Gerson, N.C.; Hagfors, T.; Newman, D.B. Jr.; Showen, R.L.

    1988-07-01

    Soviet published literature in ionospheric modification research by high-power radio waves is assessed, including an evaluation of its impact on and applications to future remote-sensing and telecommunications systems. This assessment is organized to place equal emphasis on basic research activities, designed to investigate both the natural geophysical environment and fundamental plasma physics; advanced research programs, such as those studying artificial ionization processes and oblique high-power radio propagation and practical system applications and operational limitations addressed by this research. The assessment indicates that the Soviet Union sustains high-quality theoretical and experimental research programs in ionospheric modification, with a breadth and level of effort greatly exceeding comparable Western programs. Soviet theoretical research tends to be analytical and intuitive, as compared to the Western emphasis on numerical simulation techniques. The Soviet experimental approach is less exploratory, designed principally to confirm theoretical predictions. Although limited by inferior diagnostic capabilities, Soviet experimental facilities are more numerous, operate on a more regular basis, and transmit radio wave powers exceeding those os Western facilities. Because of its broad scope of activity, the Soviet Union is better poised to quickly exploit new technologies and system applications as they are developed. This panel has identified several key areas of Soviet research activity and emerging technology that may offer long-term opportunities for remote-sensing and telecommunications advantages. However, we have found no results that suggest imminent breakthrough discoveries in these fields.

  15. Ceramic surface modifications induced by pulsed laser treatment

    NASA Astrophysics Data System (ADS)

    Cappelli, E.; Orlando, S.; Sciti, D.; Montozzi, M.; Pandolfi, L.

    2000-02-01

    Technical polycrystalline sintered Al 2O 3 (90%) substrates have been irradiated, in a vacuum chamber, at grazing incident angles (˜30°), with pulsed ArF ( λ=193 nm, hν=6.4 eV) excimer laser, at different fluences and numbers of pulses, to modify the structure and morphology of the surface. Vacuum, inert gas and oxygen atmospheres, at different substrate temperatures, ˜25°C and ˜700°C, have been used to study surface chemistry and morphology modifications induced by laser energy. Surface chemistry has been analysed by XPS spectroscopy. Morphological modifications have been studied by SEM/EDS microscopy. Changes in surface roughness have been quantified by a standard profilometer.

  16. Artificial modification meeting reminder

    NASA Astrophysics Data System (ADS)

    Gordon, W. E.

    A symposium on artificial modification of the ionosphere by high-powered radio waves (V. V. Migulin, Honorary Chairman) will be held September 19-23, 1988, at the Scandic Hotel, Tromso, Norway. The symposium, sponsored by Union Radio Scientifique Internationale Commissions (URSI) G and H, is in the URSI series which started at Suzdal in 1983. Information on the scientific program is available from V.V. Migulin, U.S.S.R. Academy of Sciences, 103907, Moscow Center, Marx Avl8, U.S.S.R.; Peter Stubbe, Max- Planck-Institut fuer Aeronomy, D-3411 Katlenburg- Lindau 3, Federal Republic of Germany; or W.E. Gordon, Rice University, Space Physics and Astronomy Dept., Houston, TX 77251. For local arrangements information, contact Asgeir Brekke, Institute Matematisk Realfag, Aurora Observatory, Box 953, N-9001, Tromso, Norway.

  17. Surface modification for interaction study with bacteria and preosteoblast cells

    NASA Astrophysics Data System (ADS)

    Song, Qing

    Surface modification plays a pivotal role in bioengineering. Polymer coatings can provide biocompatibility and biofunctionalities to biomaterials through surface modification. In this dissertation, initiated chemical vapor deposition (iCVD) was utilized to coat two-dimensional (2D) and three-dimensional (3D) substrates with differently charged polyelectrolytes in order to generate antimicrobial and osteocompatible biomaterials. ICVD is a modified CVD technique that enables surface modification in an all-dry condition without substrate damage and solvent contamination. The free-radical polymerization allows the vinyl polymers to conformally coat on various micro- and nano-structured substrates and maintains the delicate structure of the functional groups. The vapor deposition of polycations provided antimicrobial activity to planar and porous substrates through destroying the negatively charged bacterial membrane and brought about high contact-killing efficiency (99.99%) against Gram-positive Bacillus subtilis and Gram-negative Escherichia coli. Additionally, the polyampholytes synthesized by iCVD exhibited excellent antifouling performance against the adhesion of Gram-positive Listeria innocua and Gram-negative E. coli in phosphate buffered saline (PBS). Their antifouling activities were attributed to the electrostatic interaction and hydration layers that served as physical and energetic barriers to prevent bacterial adhesion. The contact-killing and antifouling polymers synthesized by iCVD can be applied to surface modification of food processing equipment and medical devices with the aim of reducing foodborne diseases and medical infections. Moreover, the charged polyelectrolyte modified 2D polystyrene surfaces displayed good osteocompatibility and enhanced osteogenesis of preosteoblast cells than the un-modified polystyrene surface. In order to promote osteoinduction of hydroxyapatite (HA) scaffolds, bioinspired polymer-controlled mineralization was conducted

  18. Evaluation of Algal Biofilms on Indium Tin Oxide (ITO) for Use in Biophotovoltaic Platforms Based on Photosynthetic Performance

    PubMed Central

    Ng, Fong-Lee; Phang, Siew-Moi; Periasamy, Vengadesh; Yunus, Kamran; Fisher, Adrian C.

    2014-01-01

    In photosynthesis, a very small amount of the solar energy absorbed is transformed into chemical energy, while the rest is wasted as heat and fluorescence. This excess energy can be harvested through biophotovoltaic platforms to generate electrical energy. In this study, algal biofilms formed on ITO anodes were investigated for use in the algal biophotovoltaic platforms. Sixteen algal strains, comprising local isolates and two diatoms obtained from the Culture Collection of Marine Phytoplankton (CCMP), USA, were screened and eight were selected based on the growth rate, biochemical composition and photosynthesis performance using suspension cultures. Differences in biofilm formation between the eight algal strains as well as their rapid light curve (RLC) generated using a pulse amplitude modulation (PAM) fluorometer, were examined. The RLC provides detailed information on the saturation characteristics of electron transport and overall photosynthetic performance of the algae. Four algal strains, belonging to the Cyanophyta (Cyanobacteria) Synechococcus elongatus (UMACC 105), Spirulina platensis. (UMACC 159) and the Chlorophyta Chlorella vulgaris (UMACC 051), and Chlorella sp. (UMACC 313) were finally selected for investigation using biophotovoltaic platforms. Based on power output per Chl-a content, the algae can be ranked as follows: Synechococcus elongatus (UMACC 105) (6.38×10−5 Wm−2/µgChl-a)>Chlorella vulgaris UMACC 051 (2.24×10−5 Wm−2/µgChl-a)>Chlorella sp.(UMACC 313) (1.43×10−5 Wm−2/µgChl-a)>Spirulina platensis (UMACC 159) (4.90×10−6 Wm−2/µgChl-a). Our study showed that local algal strains have potential for use in biophotovoltaic platforms due to their high photosynthetic performance, ability to produce biofilm and generation of electrical power. PMID:24874081

  19. Evaluation of algal biofilms on indium tin oxide (ITO) for use in biophotovoltaic platforms based on photosynthetic performance.

    PubMed

    Ng, Fong-Lee; Phang, Siew-Moi; Periasamy, Vengadesh; Yunus, Kamran; Fisher, Adrian C

    2014-01-01

    In photosynthesis, a very small amount of the solar energy absorbed is transformed into chemical energy, while the rest is wasted as heat and fluorescence. This excess energy can be harvested through biophotovoltaic platforms to generate electrical energy. In this study, algal biofilms formed on ITO anodes were investigated for use in the algal biophotovoltaic platforms. Sixteen algal strains, comprising local isolates and two diatoms obtained from the Culture Collection of Marine Phytoplankton (CCMP), USA, were screened and eight were selected based on the growth rate, biochemical composition and photosynthesis performance using suspension cultures. Differences in biofilm formation between the eight algal strains as well as their rapid light curve (RLC) generated using a pulse amplitude modulation (PAM) fluorometer, were examined. The RLC provides detailed information on the saturation characteristics of electron transport and overall photosynthetic performance of the algae. Four algal strains, belonging to the Cyanophyta (Cyanobacteria) Synechococcus elongatus (UMACC 105), Spirulina platensis. (UMACC 159) and the Chlorophyta Chlorella vulgaris (UMACC 051), and Chlorella sp. (UMACC 313) were finally selected for investigation using biophotovoltaic platforms. Based on power output per Chl-a content, the algae can be ranked as follows: Synechococcus elongatus (UMACC 105) (6.38×10(-5) Wm(-2)/µgChl-a)>Chlorella vulgaris UMACC 051 (2.24×10(-5) Wm(-2)/µgChl-a)>Chlorella sp.(UMACC 313) (1.43×10(-5) Wm(-2)/µgChl-a)>Spirulina platensis (UMACC 159) (4.90×10(-6) Wm(-2)/µgChl-a). Our study showed that local algal strains have potential for use in biophotovoltaic platforms due to their high photosynthetic performance, ability to produce biofilm and generation of electrical power.

  20. Reactive Sputter Deposition of WO3/Ag/WO3 Film for Indium Tin Oxide (ITO)-Free Electrochromic Devices.

    PubMed

    Yin, Yi; Lan, Changyong; Guo, Huayang; Li, Chun

    2016-02-17

    Functioning both as electrochromic (EC) and transparent-conductive (TC) coatings, WO3/Ag/WO3 (WAW) trilayer film shows promising potential application for ITO-free electrochromic devices. Reports on thermal-evaporated WAW films revealed that these bifunctional WAW films have distinct EC characteristics; however, their poor adhesive property leads to rapid degradation of coloring-bleaching cycling. Here, we show that WAW film with improved EC durability can be prepared by reactive sputtering using metal targets. We find that, by introducing an ultrathin tungsten (W) sacrificial layer before the deposition of external WO3, the oxidation of silver, which leads to film insulation and apparent optical haze, can be effectively avoided. We also find that the luminous transmittance and sheet resistance were sensitive to the thicknesses of tungsten and silver layers. The optimized structure for TC coating was obtained to be WO3 (45 nm)/Ag (10 nm)/W (2 nm)/WO3 (45 nm) with a sheet resistance of 16.3 Ω/□ and a luminous transmittance of 73.7%. Such film exhibits compelling EC performance with decent luminous transmittance modulation ΔTlum of 29.5%, fast switching time (6.6 s for coloring and 15.9 s for bleaching time), and long-term cycling stability (2000 cycles) with an applied potential of ±1.2 V. Thicker external WO3 layer (45/10/2/100 nm) leads to larger modulation with maximum ΔTlum of 46.4%, but at the cost of significantly increasing the sheet resistance. The strategy of introducing ultrathin metal sacrificial layer to avoid silver oxidation could be extended to fabricating other oxide-Ag-oxide transparent electrodes via low-cost reactive sputtering.

  1. Roll-to-roll printed silver nanowires for increased stability of flexible ITO-free organic solar cell modules

    NASA Astrophysics Data System (ADS)

    Dos Reis Benatto, Gisele A.; Roth, Bérenger; Corazza, Michael; Søndergaard, Roar R.; Gevorgyan, Suren A.; Jørgensen, Mikkel; Krebs, Frederik C.

    2015-12-01

    We report the use of roll-to-roll printed silver nanowire networks as front electrodes for fully roll-to-roll processed flexible indium-tin-oxide (ITO) free OPV modules. We prepared devices with two types of back electrodes, a simple PEDOT:PSS back electrode and a PEDOT:PSS back electrode with a printed silver grid in order to simultaneously explore the influence of the back electrode structure on the operational stability of the modules that did not include any UV-protection. We subjected the devices to stability testing under a number of protocols recommended by the international summit on OPV stability (ISOS). We explored accelerated ISOS-D-2, ISOS-D-3, ISOS-L-2, ISOS-L-3, ISOS-O-1 and ISOS-O-2 testing protocols and compared the performance to previous reports employing the same testing protocols on devices with PEDOT:PSS instead of the silver nanowires in the front electrode. We find significantly increased operational stability across all ISOS testing protocols over the course of the study and conclude that replacement of PEDOT:PSS in the front electrode with silver nanowires increase operational stability by up to 1000%. The duration of the tests were in the range of 140-360 days. The comparison of front and back electrode stability in this study shows that the modules with silver nanowire front electrodes together with a composite back electrode comprising PEDOT:PSS and a silver grid present the best operational stability.

  2. Wettability patterning of hydroxyapatite nanobioceramics induced by surface potential modification

    SciTech Connect

    Aronov, D.; Rosenman, G.; Karlov, A.; Shashkin, A.

    2006-04-17

    Hydroxyapatite is known as a substrate for effective adhesion of various biological cells and bacteria as well implantable biomimetic material replacing defective bone tissues. It is found that low energy electron irradiation induces its strong surface potential variation and gives rise to pronounced wettability modification. The found electron-modulation method of the hydroxyapatite wettability enables both wettability switching and its microscopic patterning, which may be used for fabrication of spatially arrayed hydroxyapatite for biological cells immobilization, gene transfer, etc.

  3. Inactivation and covalent modification of CTP synthetase by thiourea dioxide.

    PubMed Central

    Robertson, J. G.; Sparvero, L. J.; Villafranca, J. J.

    1992-01-01

    Thiourea dioxide was used in chemical modification studies to identify functionally important amino acids in Escherichia coli CTP synthetase. Incubation at pH 8.0 in the absence of substrates led to rapid, time dependent, and irreversible inactivation of the enzyme. The second-order rate constant for inactivation was 0.18 M-1 s-1. Inactivation also occurred in the absence of oxygen and in the presence of catalase, thereby ruling out mixed-function oxidation/reduction as the mode of amino acid modification. Saturating concentrations of the substrates ATP and UTP, and the allosteric activator GTP prevented inactivation by thiourea dioxide, whereas saturating concentrations of glutamine (a substrate) did not. The concentration dependence of nucleotide protection revealed cooperative behavior with respect to individual nucleotides and with respect to various combinations of nucleotides. Mixtures of nucleotides afforded greater protection against inactivation than single nucleotides alone, and a combination of the substrates ATP and UTP provided the most protection. The Hill coefficient for nucleotide protection was approximately 2 for ATP, UTP, and GTP. In the presence of 1:1 ratios of ATP:UTP, ATP:GTP, and UTP:GTP, the Hill coefficient was approximately 4 in each case. Fluorescence and circular dichroism measurements indicated that modification by thiourea dioxide causes detectable changes in the structure of the protein. Modification with [14C]thiourea dioxide demonstrated that complete inactivation correlates with incorporation of 3 mol of [14C]thiourea dioxide per mole of CTP synthetase monomer. The specificity of thiourea dioxide for lysine residues indicates that one or more lysines are most likely involved in CTP synthetase activity. The data further indicate that nucleotide binding prevents access to these functionally important residues. PMID:1303749

  4. Public perceptions of hurricane modification.

    PubMed

    Klima, Kelly; Bruine de Bruin, Wändi; Morgan, M Granger; Grossmann, Iris

    2012-07-01

    If hurricane modification were to become a feasible strategy for potentially reducing hurricane damages, it would likely generate public discourse about whether to support its implementation. To facilitate an informed and constructive discourse, policymakers need to understand how people perceive hurricane modification. Here, we examine Florida residents' perceptions of hurricane modification techniques that aim to alter path and wind speed. Following the mental models approach, we conducted a survey study about public perceptions of hurricane modification that was guided by formative interviews on the topic. We report a set of four primary findings. First, hurricane modification was perceived as a relatively ineffective strategy for damage reduction, compared to other strategies for damage reduction. Second, hurricane modification was expected to lead to changes in projected hurricane path, but not necessarily to the successful reduction of projected hurricane strength. Third, more anger was evoked when a hurricane was described as having changed from the initially forecasted path or strength after an attempted modification. Fourth, unlike what we expected, participants who more strongly agreed with statements that recognized the uncertainty inherent in forecasts reported more rather than less anger at scientists across hurricane modification scenarios. If the efficacy of intensity-reduction techniques can be increased, people may be willing to support hurricane modification. However, such an effort would need to be combined with open and honest communications to members of the general public.

  5. HMG Modifications and Nuclear Function

    PubMed Central

    Zhang, Qingchun; Wang, Yinsheng

    2009-01-01

    High mobility group (HMG) proteins assume important roles in regulating chromatin dynamics, transcriptional activities of genes and other cellular processes. Post-translational modifications of HMG proteins can alter their interactions with DNA and proteins, and consequently, affect their biological activities. Although the mechanisms through which these modifications are involved in regulating biological processes in different cellular contexts are not fully understood, new insights into these modification “codes” have emerged from the increasing appreciation of the functions of these proteins. In this review, we focus on the chemical modifications of mammalian HMG proteins and highlight their roles in nuclear functions. PMID:20123066

  6. Deposition of magnetoelectric hexaferrite thin films on substrates of silicon

    NASA Astrophysics Data System (ADS)

    Zare, Saba; Izadkhah, Hessam; Vittoria, Carmine

    2016-12-01

    Magnetoelectric M-type hexaferrite thin films (SrCo2Ti2Fe8O19) were deposited using Pulsed Laser Deposition (PLD) technique on Silicon substrate. A conductive oxide layer of Indium-Tin Oxide (ITO) was deposited as a buffer layer with the dual purposes of 1) to reduce lattice mismatch between the film and silicon and 2) to lower applied voltages to observe magnetoelectric effects at room temperature on Silicon based devices. The film exhibited magnetoelectric effects as confirmed by vibrating sample magnetometer (VSM) techniques in voltages as low as 0.5 V. Without the oxide conductive layer the required voltages to observe magnetoelectric effects was typically about 1000 times larger. The magnetoelectric thin films were characterized by X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy, vibrating sample magnetometer, and ferromagnetic resonance techniques. We measured saturation magnetization of 650 G, and coercive field of about 150 Oe for these thin films. The change in remanence magnetization was measured in the presence of DC voltages and the changes in remanence were in the order of 15% with the application of only 0.5 V (DC voltage). We deduced a magnetoelectric coupling, α, of 1.36×10-9 s m-1 in SrCo2Ti2Fe8O19 thin films.

  7. High‐Volume Processed, ITO‐Free Superstrates and Substrates for Roll‐to‐Roll Development of Organic Electronics

    PubMed Central

    Hösel, Markus; Angmo, Dechan; Søndergaard, Roar R.; dos Reis Benatto, Gisele A.; Carlé, Jon E.; Jørgensen, Mikkel

    2014-01-01

    The fabrication of substrates and superstrates prepared by scalable roll‐to‐roll methods is reviewed. The substrates and superstrates that act as the flexible carrier for the processing of functional organic electronic devices are an essential component, and proposals are made about how the general availability of various forms of these materials is needed to accelerate the development of the field of organic electronics. The initial development of the replacement of indium‐tin‐oxide (ITO) for the flexible carrier materials is described and a description of how roll‐to‐roll processing development led to simplification from an initially complex make‐up to higher performing materials through a more simple process is also presented. This process intensification through process simplification is viewed as a central strategy for upscaling, increasing throughput, performance, and cost reduction. PMID:27980893

  8. Growth factor and co-receptor release by structural regulation of substrate metalloprotease accessibility

    PubMed Central

    Parra, Liseth M.; Hartmann, Monika; Schubach, Salome; Ma, Junzhi; Herrlich, Peter; Herrlich, Andreas

    2016-01-01

    Release of cytokines, growth factors and other life-essential molecules from precursors by a-disintegrin-and-metalloproteases (ADAMs) is regulated with high substrate-specificity. We hypothesized that this is achieved by cleavage-regulatory intracellular-domain (ICD)-modifications of the precursors. We show here that cleavage-stimuli-induced specific ICD-modifications cause structural substrate changes that enhance ectodomain sensitivity of neuregulin-1 (NRG1; epidermal-growth-factor) or CD44 (receptor-tyrosine-kinase (RTK) co-receptor) to chymotrypsin/trypsin or soluble ADAM. This inside-out signal transfer required substrate homodimerization and was prevented by cleavage-inhibitory ICD-mutations. In chimeras, regulation could be conferred to a foreign ectodomain, suggesting a common higher-order structure. We predict that substrate-specific protease-accessibility-regulation controls release of numerous ADAM substrates. PMID:27876763

  9. Electrical field modification of dynamic magnetic properties in FeCo films grown onto [Pb(Mg1/3Nb2/3)O3]0.68-[PbTiO3]0.32(011) piezoelectric substrates with Ru underlayers

    NASA Astrophysics Data System (ADS)

    Phuoc, Nguyen N.; Ong, C. K.

    2015-06-01

    A detailed investigation of electrical tuning of dynamic magnetization of the FeCo magnetic thin film grown onto a PMN-PT piezoelectric substrate was carried out based on the measurement of the zero-field permeability spectra under the application of a voltage across the thickness of the substrate. The resonance frequency can be tuned from 2.95 GHz to 5.9 GHz upon the application of a voltage on the sample in unpoled state. After poling, the resonance frequency of the sample can be tuned in the range from 4.75 GHz to 5.9 GHz. In addition, it was found that after poling the peak of the permeability spectra is broadened compared to before poling, which can be tentatively attributed to the magnetic anisotropy dispersion arising from the presence of the stress-induced anisotropy. The result is also discussed in conjunction with the angular measurement of the static hysteresis loops of the sample before and after poling.

  10. Cell Signalling Through Covalent Modification and Allostery

    NASA Astrophysics Data System (ADS)

    Johnson, Louise N.

    Phosphorylation plays essential roles in nearly every aspect of cell life. Protein kinases catalyze the transfer of the γ-phosphate of ATP to a serine, threonine or tyrosine residue in protein substrates. This covalent modification allows activation or inhibition of enzyme activity, creates recognition sites for other proteins and promotes order/disorder or disorder/order transitions. These properties regulate ­signalling pathways and cellular processes that mediate metabolism, transcription, cell cycle progression, differentiation, cytoskeleton arrangement and cell movement, apoptosis, intercellular communication, and neuronal and immunological functions. In this lecture I shall review the structural consequences of protein phosphorylation using our work on glycogen phosphorylase and the cell cycle cyclin dependent protein kinases as illustrations. Regulation of protein phosphorylation may be disrupted in the diseased state and protein kinases have become high profile targets for drug development. To date there are 11 compounds that have been approved for clinical use in the treatment of cancer.

  11. Flexible electrochromics: magnetron sputtered tungsten oxide (WO3-x) thin films on Lexan (optically transparent polycarbonate) substrates

    NASA Astrophysics Data System (ADS)

    Uday Kumar, K.; Murali, Dhanya S.; Subrahmanyam, A.

    2015-06-01

    Tungsten oxide (WO3-x) based electrochromics on flexible substrates is a topic of recent interest. The present communication reports the electrochromic properties of WO3-x thin films grown on lexan, an optically transparent polycarbonate thermoplastic substrate. The WO3-x films are prepared at room temperature (300 K) by the reactive DC magnetron sputtering technique. The physical properties of metal oxide thin films are known to be controlled by the oxygen stoichiometry of the film. In the present work, the WO3-x thin films are prepared by varying the oxygen flow rates. All the WO3-x thin films are amorphous in nature. The electrochromic performance of the WO3-x thin films is evaluated by cyclic voltammetry measurements on tin doped indium oxide (ITO) coated lexan and glass substrates. The optical band gap of WO3-x thin films grown on lexan substrates (at any given oxygen flow rate) is significantly higher than those grown on glass substrates. The coloration efficiency of WO3-x thin films (at an oxygen flow rate of 10 sccm) on lexan substrates is: 143.9 cm2 C-1 which is higher compared to that grown on glass: 90.4 cm2 C-1.

  12. Highly conductive and low cost Ni-PET flexible substrate for efficient dye-sensitized solar cells.

    PubMed

    Su, Haijun; Zhang, Mingyang; Chang, Ya-Huei; Zhai, Peng; Hau, Nga Yu; Huang, Yu-Ting; Liu, Chang; Soh, Ai Kah; Feng, Shien-Ping

    2014-04-23

    The highly conductive and flexible nickel-polyethylene terephthalate (Ni-PET) substrate was prepared by a facile way including electrodeposition and hot-press transferring. The effectiveness was demonstrated in the counter electrode of dye-sensitized solar cells (DSSCs). The Ni film electrodeposition mechanism, microstructure, and DSSC performance for the Ni-PET flexible substrate were investigated. The uniform and continuous Ni film was first fabricated by electroplating metallic Ni on fluorine-doped tin oxide (FTO) and then intactly transferred onto PET via hot-pressing using Surlyn as the joint adhesive. The obtained flexible Ni-PET substrate shows low sheet resistance of 0.18Ω/□ and good chemical stability for the I(-)/I(3-) electrolyte. A high light-to-electric energy conversion efficiency of 7.89% was demonstrated in DSSCs system based on this flexible electrode substrate due to its high conductivity, which presents an improvement of 10.4% as compared with the general ITO-PEN flexible substrate. This method paves a facile and cost-effective way to manufacture various metals on a plastic nonconducive substrate beneficial for the devices toward flexible and rollable.

  13. Imidazolium-based titanium substrates against bacterial colonization.

    PubMed

    Cavoue, T; Bounou Abassi, H; Vayssade, M; Nguyen Van Nhien, A; Kang, I-K; Kwon, G-W; Pourceau, G; Dubot, P; Abbad Andaloussi, S; Versace, D-L

    2017-02-28

    Nosocomial infections are often induced by the presence of pathogenic organisms on the surface of medical devices or hospital equipment. Chemical modifications of the surface are recognized as efficient strategies to prevent bacterial adhesion but they may have a negative impact on the material's interaction with living tissues. Here we have developed a photoactivated method for the modification of titanium substrates. A photoinduced technique employing a grafting-onto process has been successfully performed to covalently anchor an imidazolium-derivative siloxane onto titanium surfaces. Imidazolium surfaces showed higher bacteria-repellency performances than native titanium substrates, achieving more than 98% anti-adhesion efficiency against Escherichia coli after 24 h of incubation. In addition, these surfaces allowed for the adhesion and viability of osteoblasts cells without evidence of cytotoxicity.

  14. Direct growth of NiCo2O4 nanostructures on conductive substrates with enhanced electrocatalytic activity and stability for methanol oxidation

    NASA Astrophysics Data System (ADS)

    Qian, Lei; Gu, Li; Yang, Li; Yuan, Hongyan; Xiao, Dan

    2013-07-01

    In this report, NiCo2O4 nanostructures with different morphologies were directly grown on conductive substrates (stainless steel and ITO) by a facile electrodeposition method in addition to a post-annealing process. The morphology changes on different conductive substrates are discussed in detail. The NiCo2O4 on stainless steel (SS) had a high surface area (119 m2 g-1) and was successfully used in the electrocatalytic oxidation of methanol. The electrocatalytic performance was investigated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS) measurements. Impressively, the NiCo2O4 showed much higher electrocatalytic activity, lower overpotential and greater stability compared to that of only NiO or Co3O4 synthesized by the same method. The higher electrocatalytic activity is due to the high electron conductivity, large surface area of NiCo2O4 and the fast ion/electron transport in the electrode and at the electrolyte-electrode interface. This is important for further development of high performance non-platinum electrocatalysts for application in direct methanol fuel cells.In this report, NiCo2O4 nanostructures with different morphologies were directly grown on conductive substrates (stainless steel and ITO) by a facile electrodeposition method in addition to a post-annealing process. The morphology changes on different conductive substrates are discussed in detail. The NiCo2O4 on stainless steel (SS) had a high surface area (119 m2 g-1) and was successfully used in the electrocatalytic oxidation of methanol. The electrocatalytic performance was investigated by cyclic voltammetry (CV), chronoamperometry and electrochemical impedance spectroscopy (EIS) measurements. Impressively, the NiCo2O4 showed much higher electrocatalytic activity, lower overpotential and greater stability compared to that of only NiO or Co3O4 synthesized by the same method. The higher electrocatalytic activity is due to the high electron conductivity

  15. All-inorganic large-area low-cost and durable flexible perovskite solar cells using copper foil as a substrate.

    PubMed

    Abdollahi Nejand, B; Nazari, P; Gharibzadeh, S; Ahmadi, V; Moshaii, A

    2017-01-05

    Here, a low-cost perovskite solar cell using CuI and ZnO as the respective inorganic hole and electron transport layers is introduced. Copper foil is chosen as a cheap and low-weight conductive substrate which has a similar work function to ITO. Besides, copper foil is an interesting copper atom source for the growth of the upper cuprous iodide layer on copper foil. A spray coating of a transparent silver nanowire electrode is used as a top contact. The prepared device shows a maximum power conversion efficiency of 12.80% and long-term durability providing an environmentally and market friendly perovskite solar cell.

  16. Nitrification in a zeoponic substrate.

    PubMed

    McGilloway, R L; Weaver, R W; Ming, D W; Gruener, J E

    2003-10-01

    Clinoptilolite is a zeolite mineral with high cation exchange capacity used in zeoponic substrates that have been proposed as a solid medium for growing plants or as a fertilizer material. The kinetics of nitrification has not been measured for NH4+ saturated zeoponic substrate. Experiments were conducted to evaluate the production of NO2- and NO3-, and nitrifier populations in zeoponic substrates. Small columns were filled with zeoponic substrate inoculated with a commercial inoculum or soil enrichment culture of nitrifying bacteria. In addition to column studies, a growth chamber study was conducted to evaluate the kinetics of nitrification in zeoponic substrates used to grow radishes (Raphanus sativus L.). The zeoponic substrate provided a readily available source of NH4+, and nitrifying bacteria were active in the substrate. Ammonium oxidation rates in column studies ranged from 5 to 10 micrograms N g-1 substrate h-1, and NO2- oxidation rates were 2 to 9.5 micrograms N g-1 substrate h-1. Rates determined from the growth chamber study were approximately 1.2 micrograms N g-1 substrate h-1. Quantities of NH4+ oxidized to NO2- and NO3- in inoculated zeoponic substrate were in excess of plant up-take. Acidification as a result of NH4+ oxidation resulted in a pH decline, and the zeoponic substrate showed limited buffering capacity.

  17. Nitrification in a zeoponic substrate

    NASA Technical Reports Server (NTRS)

    McGilloway, R. L.; Weaver, R. W.; Ming, D. W.; Gruener, J. E.

    2003-01-01

    Clinoptilolite is a zeolite mineral with high cation exchange capacity used in zeoponic substrates that have been proposed as a solid medium for growing plants or as a fertilizer material. The kinetics of nitrification has not been measured for NH4+ saturated zeoponic substrate. Experiments were conducted to evaluate the production of NO2- and NO3-, and nitrifier populations in zeoponic substrates. Small columns were filled with zeoponic substrate inoculated with a commercial inoculum or soil enrichment culture of nitrifying bacteria. In addition to column studies, a growth chamber study was conducted to evaluate the kinetics of nitrification in zeoponic substrates used to grow radishes (Raphanus sativus L.). The zeoponic substrate provided a readily available source of NH4+, and nitrifying bacteria were active in the substrate. Ammonium oxidation rates in column studies ranged from 5 to 10 micrograms N g-1 substrate h-1, and NO2- oxidation rates were 2 to 9.5 micrograms N g-1 substrate h-1. Rates determined from the growth chamber study were approximately 1.2 micrograms N g-1 substrate h-1. Quantities of NH4+ oxidized to NO2- and NO3- in inoculated zeoponic substrate were in excess of plant up-take. Acidification as a result of NH4+ oxidation resulted in a pH decline, and the zeoponic substrate showed limited buffering capacity.

  18. Chromatin modification in zebrafish development.

    PubMed

    Cayuso Mas, Jordi; Noël, Emily S; Ober, Elke A

    2011-01-01

    The generation of complex organisms requires that an initial population of cells with identical gene expression profiles can adopt different cell fates during development by progressively diverging transcriptional programs. These programs depend on the binding of transcritional regulators to specific genomic sites, which in turn is controlled by modifications of the chromatin. Chromatin modifications may occur directly upon DNA by methylation of specific nucleotides, or may involve post-translational modification of histones. Local regulation of histone post-translational modifications regionalizes the genome into euchromatic regions, which are more accessible to DNA-binding factors, and condensed heterochromatic regions, inhibiting the binding of such factors. In addition, these modifications may be required in a genome-wide fashion for processes such as DNA replication or chromosome condensation. From an embryologist's point of view chromatin modifications are intensively studied in the context of imprinting and have more recently received increasing attention in understanding the basis of pluripotency and cellular differentiation. Here, we describe recently uncovered roles of chromatin modifications in zebrafish development and regeneration, as well as available resources and commonly used techniques. We provide a general introduction into chromatin modifications and their respective functions with a focus on gene transcription, as well as key aspects of their roles in the early zebrafish embryo, neural development, formation of the digestive system and tissue regeneration.

  19. Body Modification and Suicidal Behavior

    ERIC Educational Resources Information Center

    Hicinbothem, Julie; Gonsalves, Sonia; Lester, David

    2006-01-01

    In a large sample of individuals who belong to a website for body modification, having body modifications (e.g., piercings, tattoos, scarification and surgical procedures) was associated with a higher incidence of prior suicidality (i.e., suicidal ideation and attempted suicide). However, controls for self-reported depression weakened the strength…

  20. Surface Modification of Intraocular Lenses

    PubMed Central

    Huang, Qi; Cheng, George Pak-Man; Chiu, Kin; Wang, Gui-Qin

    2016-01-01

    Objective: This paper aimed to review the current literature on the surface modification of intraocular lenses (IOLs). Data Sources: All articles about surface modification of IOLs published up to 2015 were identified through a literature search on both PubMed and ScienceDirect. Study Selection: The articles on the surface modification of IOLs were included, but those on design modification and surface coating were excluded. Results: Technology of surface modification included plasma, ion beam, layer-by-layer self-assembly, ultraviolet radiation, and ozone. The main molecules introduced into IOLs surface were poly (ethylene glycol), polyhedral oligomeric silsesquioxane, 2-methacryloyloxyethyl phosphorylcholine, TiO2, heparin, F-heparin, titanium, titanium nitride, vinyl pyrrolidone, and inhibitors of cytokines. The surface modification either resulted in a more hydrophobic lens, a more hydrophilic lens, or a lens with a hydrophilic anterior and hydrophobic posterior surface. Advances in research regarding surface modification of IOLs had led to a better biocompatibility in both in vitro and animal experiments. Conclusion: The surface modification is an efficient, convenient, economic and promising method to improve the biocompatibility of IOLs. PMID:26830993

  1. Excimer laser surface modification: Process and properties

    SciTech Connect

    Jervis, T.R.; Nastasi, M.; Hirvonen, J.P.

    1992-12-01

    Surface modification can improve materials for structural, tribological, and corrosion applications. Excimer laser light has been shown to provide a rapid means of modifying surfaces through heat treating, surface zone refining, and mixing. Laser pulses at modest power levels can easily melt the surfaces of many materials. Mixing within the molten layer or with the gas ambient may occur, if thermodynamically allowed, followed by rapid solidification. The high temperatures allow the system to overcome kinetic barriers found in some ion mixing experiments. Alternatively, surface zone refinement may result from repeated melting-solidification cycles. Ultraviolet laser light couples energy efficiently to the surface of metallic and ceramic materials. The nature of the modification that follows depends on the properties of the surface and substrate materials. Alloying from both gas and predeposited layer sources has been observed in metals, semiconductors, and ceramics as has surface enrichment of Cr by zone refinement of stainless steel. Rapid solidification after melting often results in the formation of nonequilibrium phases, including amorphous materials. Improved surface properties, including tribology and corrosion resistance, are observed in these materials.

  2. Chemical Protein Modification through Cysteine.

    PubMed

    Gunnoo, Smita B; Madder, Annemieke

    2016-04-01

    The modification of proteins with non-protein entities is important for a wealth of applications, and methods for chemically modifying proteins attract considerable attention. Generally, modification is desired at a single site to maintain homogeneity and to minimise loss of function. Though protein modification can be achieved by targeting some natural amino acid side chains, this often leads to ill-defined and randomly modified proteins. Amongst the natural amino acids, cysteine combines advantageous properties contributing to its suitability for site-selective modification, including a unique nucleophilicity, and a low natural abundance--both allowing chemo- and regioselectivity. Native cysteine residues can be targeted, or Cys can be introduced at a desired site in a protein by means of reliable genetic engineering techniques. This review on chemical protein modification through cysteine should appeal to those interested in modifying proteins for a range of applications.

  3. Nanostructured germanium deposited on heated substrates with enhanced photoelectric properties

    PubMed Central

    Maraloiu, Valentin Adrian; Prepelita, Petronela; Iordache, Gheorghe

    2016-01-01

    Summary Obtaining high-quality materials, based on nanocrystals, at low temperatures is one of the current challenges for opening new paths in improving and developing functional devices in nanoscale electronics and optoelectronics. Here we report a detailed investigation of the optimization of parameters for the in situ synthesis of thin films with high Ge content (50 %) into SiO2. Crystalline Ge nanoparticles were directly formed during co-deposition of SiO2 and Ge on substrates at 300, 400 and 500 °C. Using this approach, effects related to Ge–Ge spacing are emphasized through a significant improvement of the spatial distribution of the Ge nanoparticles and by avoiding multi-step fabrication processes or Ge loss. The influence of the preparation conditions on structural, electrical and optical properties of the fabricated nanostructures was studied by X-ray diffraction, transmission electron microscopy, electrical measurements in dark or under illumination and response time investigations. Finally, we demonstrate the feasibility of the procedure by the means of an Al/n-Si/Ge:SiO2/ITO photodetector test structure. The structures, investigated at room temperature, show superior performance, high photoresponse gain, high responsivity (about 7 AW−1), fast response time (0.5 µs at 4 kHz) and great optoelectronic conversion efficiency of 900% in a wide operation bandwidth, from 450 to 1300 nm. The obtained photoresponse gain and the spectral width are attributed mainly to the high Ge content packed into a SiO2 matrix showing the direct connection between synthesis and optical properties of the tested nanostructures. Our deposition approach put in evidence the great potential of Ge nanoparticles embedded in a SiO2 matrix for hybrid integration, as they may be employed in structures and devices individually or with other materials, hence the possibility of fabricating various heterojunctions on Si, glass or flexible substrates for future development of Si

  4. Dewetting on microstructured substrates

    NASA Astrophysics Data System (ADS)

    Kim, Taehong; Kim, Wonjung

    2016-11-01

    A thin liquid film has an equilibrium thickness in such a way as to minimize the free energy. When a liquid film thickness is out of its equilibrium, the film seeks its equilibrium state, resulting in dynamics of liquid film, which are referred to as wetting and dewetting, depending on the flow direction. We here present a combined experimental and theoretical investigation of dewetting on a substrate with parallel microstructures. Our experiments show that residue may remain on the substrate after dewetting, and residue morphologies can be classified into three modes. Based on our experimental observations, we elucidate how the modes depend on the pattern morphology and contact angle, and develop a model for the contact line motion. Our results provide a basis for controlling the thickness film, which is important for many practical applications such as oil recovery, detergency, lithography, and cleaning. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No.2015R1A2A2A04006181).

  5. Covalent modification of graphene and graphite using diazonium chemistry: tunable grafting and nanomanipulation.

    PubMed

    Greenwood, John; Phan, Thanh Hai; Fujita, Yasuhiko; Li, Zhi; Ivasenko, Oleksandr; Vanderlinden, Willem; Van Gorp, Hans; Frederickx, Wout; Lu, Gang; Tahara, Kazukuni; Tobe, Yoshito; Uji-I, Hiroshi; Mertens, Stijn F L; De Feyter, Steven

    2015-05-26

    We shine light on the covalent modification of graphite and graphene substrates using diazonium chemistry under ambient conditions. We report on the nature of the chemical modification of these graphitic substrates, the relation between molecular structure and film morphology, and the impact of the covalent modification on the properties of the substrates, as revealed by local microscopy and spectroscopy techniques and electrochemistry. By careful selection of the reagents and optimizing reaction conditions, a high density of covalently grafted molecules is obtained, a result that is demonstrated in an unprecedented way by scanning tunneling microscopy (STM) under ambient conditions. With nanomanipulation, i.e., nanoshaving using STM, surface structuring and functionalization at the nanoscale is achieved. This manipulation leads to the removal of the covalently anchored molecules, regenerating pristine sp(2) hybridized graphene or graphite patches, as proven by space-resolved Raman microscopy and molecular self-assembly studies.

  6. Maintainable substrate carrier for electroplating

    DOEpatents

    Chen, Chen-An; Abas, Emmanuel Chua; Divino, Edmundo Anida; Ermita, Jake Randal G.; Capulong, Jose Francisco S.; Castillo, Arnold Villamor; Ma, Diana Xiaobing

    2016-08-02

    One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The carrier includes a non-conductive carrier body on which the substrates are placed and conductive lines embedded within the carrier body. A plurality of conductive clip attachment parts are attached in a permanent manner to the conductive lines embedded within the carrier body. A plurality of contact clips are attached in a removable manner to the clip attachment parts. The contact clips hold the substrates in place and conductively connecting the substrates with the conductive lines. Other embodiments, aspects and features are also disclosed.

  7. Maintainable substrate carrier for electroplating

    DOEpatents

    Chen, Chen-An [Milpitas, CA; Abas, Emmanuel Chua [Laguna, PH; Divino, Edmundo Anida [Cavite, PH; Ermita, Jake Randal G [Laguna, PH; Capulong, Jose Francisco S [Laguna, PH; Castillo, Arnold Villamor [Batangas, PH; Ma,; Xiaobing, Diana [Saratoga, CA

    2012-07-17

    One embodiment relates to a substrate carrier for use in electroplating a plurality of substrates. The carrier includes a non-conductive carrier body on which the substrates are placed and conductive lines embedded within the carrier body. A plurality of conductive clip attachment parts are attached in a permanent manner to the conductive lines embedded within the carrier body. A plurality of contact clips are attached in a removable manner to the clip attachment parts. The contact clips hold the substrates in place and conductively connecting the substrates with the conductive lines. Other embodiments, aspects and features are also disclosed.

  8. Surface modifications of Nitinol for biomedical applications.

    PubMed

    Sun, F; Sask, K N; Brash, J L; Zhitomirsky, I

    2008-11-15

    Cathodic electrophoretic deposition (EPD) has been utilized for the fabrication of composite films for the surface modification of NiTi shape memory alloys (Nitinol). In the proposed method, chitosan (CH) was used as a matrix for the incorporation of other functional materials, such as heparin, hydroxyapatite and bioglass. Chitosan-heparin films were deposited from solutions of non-stoichiometric chitosan-heparin complexes. It was found that the addition of anionic heparin to the solutions of cationic chitosan resulted in a significant increase in the cathodic deposition rate. The thickness of the films prepared by this method varied in the range of 0.1-3 microm. The ability of the chitosan-heparin films to bind antithrombin, as measured by binding of (125)I-radiolabeled antithrombin, was much greater than that of pure chitosan films. Composite chitosan-hydroxyapatite films, with thickness of 1-30 microm, were obtained as monolayers or laminates, containing chitosan-hydroxyapatite layers, separated by layers of pure chitosan. The hydroxyapatite nanoparticles showed preferred orientation in the chitosan matrix with the c-axis parallel to the substrate surface. The films showed corrosion protection of the Nitinol substrates in Ringer's physiological solutions. The feasibility of the fabrication of composite films containing hydroxyapatite and bioglass in the chitosan matrix has been demonstrated. The method offers the advantages of room temperature processing. The deposition mechanisms and possible applications of the films are discussed.

  9. STM driven modification of bismuth nanostructures

    NASA Astrophysics Data System (ADS)

    Kowalczyk, P. J.; Mahapatra, O.; Brown, S. A.; Bian, G.; Chiang, T.-C.

    2014-03-01

    The tip of a scanning tunneling microscope (STM) gently interacting with the substrate is used to modify (110) bismuth islands deposited on highly oriented pyrolitic graphite (HOPG), and hence to investigate the atomic and electronic structure of the islands. The tip interaction leads to the evolution of metastable 3 ML thick regions into structures of higher thermodynamic stability, which in the case of bismuth on graphite are rods (typically ≥ 5 ML high) and stripes. The formation of trenches that extend along the stripes is observed which is related to the presence of kinks and weak bonds at the 3-5 ML interface. Migration of whole islands along particular substrate directions is evidence for superlubricity due to the misfit between Bi and HOPG unit cells. Perimeter diffusion through atoms and not vacancies is a driving force of all observed modifications. The Bi islands are found to be able to deform and their decay is not governed by Ostwald ripening (which is absent in this system). Instead quantum size effects play a major role in the evolution of the islands, as evidenced by the observation of preferred widths. Density functional theory calculations reveal an oval Fermi surface with de Broglie wavelength corresponding to observed width of islands. These results are all consistent with a thin film Bi allotrope which has both paired atomic layers on the surface and bulk-like chains of bonds vertically through the structure.

  10. Surface modification of bioceramics

    NASA Astrophysics Data System (ADS)

    Monkawa, Akira

    Hydroxyapatite [Ca10(PO4)6(OH)2, HAp] is a major inorganic component of bone and teeth tissues and has the excellent biocompatibility and high osteoconductivity. The interactions between HAp and protein or cell have been studied. The HAp related bioceramics such as bone substitute, coating substance of metal implants, inorganic-polymer composites, and cell culture. We described two methods; (1) surface modification of HAp using organosilane; (2) fabrication of HAp ultra-thin layer on gold surface for protein adsorption analyzed with QCM-D technique. The interfacial interaction between collagen and HAp in a nano-region was controlled by depositing the organosilane of n-octadecyltrimethoxysilane (ODS: -CH3) or aminopropyltriethoxysilane (APTS: -NH2) with a chemical vapor deposition method. The morphologies of collagen adsorbed on the surfaces of HAp and HAp deposited with APTS were similar, however that of the surface with ODS was apparently different, due to the hydrophobic interaction between the organic head group of -CH3 and residual groups of collagen. We present a method for coating gold quartz crystal microbalance with dissipation (QCM-D) sensor with ultra-thin layer of hydroxyapatite nanocrystals evenly covering and tightly bound to the surface. The hydroxyapatite sensor operated in liquid with high stability and sensitivity. The in-situ adsorption mechanism and conformational change of fibrinogen on gold, titanium and hydroxyapatite surfaces were investigated by QCM-D technique and Fourier-transform infrared spectroscopy. The study indicates that the hydroxyapatite sensor is applicable for qualitative and conformational analysis of protein adsorption.

  11. Hemocompatibility of silicon-based substrates for biomedical implant applications.

    PubMed

    Muthusubramaniam, Lalitha; Lowe, Rachel; Fissell, William H; Li, Lingyan; Marchant, Roger E; Desai, Tejal A; Roy, Shuvo

    2011-04-01

    Silicon membranes with highly uniform nanopore sizes fabricated using microelectromechanical systems (MEMS) technology allow for the development of miniaturized implants such as those needed for renal replacement therapies. However, the blood compatibility of silicon has thus far been an unresolved issue in the use of these substrates in implantable biomedical devices. We report the results of hemocompatibility studies using bare silicon, polysilicon, and modified silicon substrates. The surface modifications tested have been shown to reduce protein and/or platelet adhesion, thus potentially improving biocompatibility of silicon. Hemocompatibility was evaluated under four categories-coagulation (thrombin-antithrombin complex, TAT generation), complement activation (complement protein, C3a production), platelet activation (P-selectin, CD62P expression), and platelet adhesion. Our tests revealed that all silicon substrates display low coagulation and complement activation, comparable to that of Teflon and stainless steel, two materials commonly used in medical implants, and significantly lower than that of diethylaminoethyl (DEAE) cellulose, a polymer used in dialysis membranes. Unmodified silicon and polysilicon showed significant platelet attachment; however, the surface modifications on silicon reduced platelet adhesion and activation to levels comparable to that on Teflon. These results suggest that surface-modified silicon substrates are viable for the development of miniaturized renal replacement systems.

  12. Recognition Sequences and Substrate Evolution in Cyanobactin Biosynthesis

    PubMed Central

    2015-01-01

    Ribosomally synthesized and posttranslationally modified peptide (RiPP) natural products are of broad interest because of their intrinsic bioactivities and potential for synthetic biology. The RiPP cyanobactin pathways pat and tru have been experimentally shown to be extremely tolerant of mutations. In nature, the pathways exhibit “substrate evolution”, where enzymes remain constant while the substrates of those enzymes are hypervariable and readily evolvable. Here, we sought to determine the mechanism behind this promiscuity. Analysis of a series of different enzyme–substrate combinations from five different cyanobactin gene clusters, in addition to engineered substrates, led us to define short discrete recognition elements within substrates that are responsible for directing enzymes. We show that these recognition sequences (RSs) are portable and can be interchanged to control which functional groups are added to the final natural product. In addition to the previously assigned N- and C-terminal proteolysis RSs, here we assign the RS for heterocyclization modification. We show that substrate elements can be swapped in vivo leading to successful production of natural products in E. coli. The exchangeability of these elements holds promise in synthetic biology approaches to tailor peptide products in vivo and in vitro. PMID:24625112

  13. Graphene nanoribbons anchored to SiC substrates

    NASA Astrophysics Data System (ADS)

    Le, Nam B.; Woods, Lilia M.

    2016-09-01

    Graphene nanoribbons are quasi-one-dimensional planar graphene allotropes with diverse properties dependent on their width and types of edges. Graphene nanoribbons anchored to substrates is a hybrid system, which offers novel opportunities for property modifications as well as experimental control. Here we present electronic structure calculations of zigzag graphene nanoribbons chemically attached via the edges to the Si or C terminated surfaces of a SiC substrate. The results show that the edge characteristics are rather robust and the properties are essentially determined by the individual nanoribbon. While the localized spin polarization of the graphene nanoribbon edge atoms is not significantly affected by the substrate, secondary energy gaps in the highest conduction and lowest valence region may emerge in the anchored structures. The van der Waals interaction together with the electrostatic interactions due to the polarity of the surface bonds are found to be important for the structure parameters and energy stability.

  14. Systematic approaches to identify E3 ligase substrates

    PubMed Central

    Iconomou, Mary; Saunders, Darren N.

    2016-01-01

    Protein ubiquitylation is a widespread post-translational modification, regulating cellular signalling with many outcomes, such as protein degradation, endocytosis, cell cycle progression, DNA repair and transcription. E3 ligases are a critical component of the ubiquitin proteasome system (UPS), determining the substrate specificity of the cascade by the covalent attachment of ubiquitin to substrate proteins. Currently, there are over 600 putative E3 ligases, but many are poorly characterized, particularly with respect to individual protein substrates. Here, we highlight systematic approaches to identify and validate UPS targets and discuss how they are underpinning rapid advances in our understanding of the biochemistry and biology of the UPS. The integration of novel tools, model systems and methods for target identification is driving significant interest in drug development, targeting various aspects of UPS function and advancing the understanding of a diverse range of disease processes. PMID:27834739

  15. Multifunctional Indium Tin Oxide Electrode Generated by Unusual Surface Modification

    NASA Astrophysics Data System (ADS)

    Bouden, Sarra; Dahi, Antoine; Hauquier, Fanny; Randriamahazaka, Hyacinthe; Ghilane, Jalal

    2016-11-01

    The indium tin oxide (ITO) material has been widely used in various scientific fields and has been successfully implemented in several devices. Herein, the electrochemical reduction of ITO electrode in an organic electrolytic solution containing alkali metal, NaI, or redox molecule, N-(ferrocenylmethyl) imidazolium iodide, was investigated. The reduced ITO surfaces were investigated by X-ray photoelectron spectroscopy and grazing incident XRD demonstrating the presence of the electrolyte cation inside the material. Reversibility of this process after re-oxidation was evidenced by XPS. Using a redox molecule based ionic liquid as supporting electrolyte leads to fellow electrochemically the intercalation process. As a result, modified ITO containing ferrocenyl imidazolium was easily generated. This reduction process occurs at mild reducing potential around ‑1.8 V and causes for higher reducing potential a drastic morphological change accompanied with a decrease of the electrode conductivity at the macroscopic scale. Finally, the self-reducing power of the reduced ITO phase was used to initiate the spontaneous reduction of silver ions leading to the growth of Ag nanoparticles. As a result, transparent and multifunctional active ITO surfaces were generated bearing redox active molecules inside the material and Ag nanoparticles onto the surface.

  16. Multifunctional Indium Tin Oxide Electrode Generated by Unusual Surface Modification

    PubMed Central

    Bouden, Sarra; Dahi, Antoine; Hauquier, Fanny; Randriamahazaka, Hyacinthe; Ghilane, Jalal

    2016-01-01

    The indium tin oxide (ITO) material has been widely used in various scientific fields and has been successfully implemented in several devices. Herein, the electrochemical reduction of ITO electrode in an organic electrolytic solution containing alkali metal, NaI, or redox molecule, N-(ferrocenylmethyl) imidazolium iodide, was investigated. The reduced ITO surfaces were investigated by X-ray photoelectron spectroscopy and grazing incident XRD demonstrating the presence of the electrolyte cation inside the material. Reversibility of this process after re-oxidation was evidenced by XPS. Using a redox molecule based ionic liquid as supporting electrolyte leads to fellow electrochemically the intercalation process. As a result, modified ITO containing ferrocenyl imidazolium was easily generated. This reduction process occurs at mild reducing potential around −1.8 V and causes for higher reducing potential a drastic morphological change accompanied with a decrease of the electrode conductivity at the macroscopic scale. Finally, the self-reducing power of the reduced ITO phase was used to initiate the spontaneous reduction of silver ions leading to the growth of Ag nanoparticles. As a result, transparent and multifunctional active ITO surfaces were generated bearing redox active molecules inside the material and Ag nanoparticles onto the surface. PMID:27857192

  17. Chatting histone modifications in mammals

    PubMed Central

    Izzo, Annalisa

    2010-01-01

    Eukaryotic chromatin can be highly dynamic and can continuously exchange between an open transcriptionally active conformation and a compacted silenced one. Post-translational modifications of histones have a pivotal role in regulating chromatin states, thus influencing all chromatin dependent processes. Methylation is currently one of the best characterized histone modification and occurs on arginine and lysine residues. Histone methylation can regulate other modifications (e.g. acetylation, phosphorylation and ubiquitination) in order to define a precise functional chromatin environment. In this review we focus on histone methylation and demethylation, as well as on the enzymes responsible for setting these marks. In particular we are describing novel concepts on the interdependence of histone modifications marks and discussing the molecular mechanisms governing this cross-talks. PMID:21266346

  18. Respiratory psychophysiology and behavior modification.

    PubMed

    Ley, R

    2001-09-01

    This article was written as an introduction to a special issue of Behavior Modification dedicated to studies in the field of respiratory psychophysiology. Although the invited articles that constitute this special issue cover a fairly broad range of topics, priority was given to articles that focus on the role of respiration in panic disorder. Attention is directed to the fundamental role of breathing in applied psychophysiology and to the encouragement of research in the modification of breathing behavior. The connection between respiratory psychophysiology and behavior modification is explained by reference to (a) a recent article on Pavlovian and operant control of breathing behavior and (b) four published volumes of selected articles dedicated exclusively to the field of respiratory psychophysiology. The present special issue of Behavior Modification marks the fifth volume.

  19. MODIFICATIONS OF THE RAND REAC,

    DTIC Science & Technology

    The major items of the modification program were the installation of a removable plugboard of the type used on the International Business Machines punched card tabulators, and a digital readout device.

  20. Data Analysis Strategies for Protein Modification Identification.

    PubMed

    Fu, Yan

    2016-01-01

    Mass spectrometry-based proteomics provides a powerful tool for large-scale analysis of protein modifications. Statistical and computational analysis of mass spectrometry data is a key step in protein modification identification. This chapter presents common and advanced data analysis strategies for modification identification, including variable modification search, unrestrictive approaches for modification discovery, false discovery rate estimation and control methods, and tools for modification site localization.