WorldWideScience

Sample records for blzt-cfo composite thin

  1. Ceramic Composite Thin Films

    Science.gov (United States)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  2. Magnetoelectric thin film composites with interdigital electrodes

    Science.gov (United States)

    Piorra, A.; Jahns, R.; Teliban, I.; Gugat, J. L.; Gerken, M.; Knöchel, R.; Quandt, E.

    2013-07-01

    Magnetoelectric (ME) thin film composites on silicon cantilevers are fabricated using Pb(Zr0.52Ti0.45)O3 (PZT) films with interdigital transducer electrodes on the top side and FeCoSiB amorphous magnetostrictive thin films on the backside. These composites without any direct interface between the piezoelectric and magnetostrictive phase are superior to conventional plate capacitor-type thin film ME composites. A limit of detection of 2.6 pT/Hz1/2 at the mechanical resonance is determined which corresponds to an improvement of a factor of approximately 2.8 compared to the best plate type sensor using AlN as the piezoelectric phase and even a factor of approximately 4 for a PZT plate capacitor.

  3. Thermoviscoelastic dynamic response for a composite material thin narrow strip

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Hong Liang; Qi, Li-Li; Liu, Hai-Bo [Hunan University, Changsha (China)

    2015-02-15

    Based on von Karman nonlinear strain-displacement relationships and classical thin plate theory, a list of nonlinear dynamic equilibrium equations for a viscoelastic composite material thin narrow strip under thermal and mechanic loads are deduced. According to the material constitutive relationship and the relaxation modulus in the form of the Prony series, combing with the Newmark method and the Newton-cotes integration method, a new numerical algorithm for direct solving the whole problem in the time domain is established. By applying this numerical algorithm, the viscoelastic composite material thin narrow strip as the research subject is analyzed systematically, and its rich dynamical behaviors are revealed comprehensively. To verify the accuracy of the present work, a comparison is made with previously published results. Finally, the viscoelastic composite material thin narrow strip under harmonic excitation load and impact load are discussed in detail, and many valuable thermoviscoelastic dynamic characteristics are revealed.

  4. Nonlinear optical properties of Au/PVP composite thin films

    Institute of Scientific and Technical Information of China (English)

    Shen Hong; Cheng Bo-Lin; Lu Guo-Wei; Wang Wei-Tian; Guan Dong-Yi; Chen Zheng-Hao; Yang Guo-Zhen

    2005-01-01

    Colloidal Au and poly(vinylpyrrolidone) (PVP) composite thin films are fabricated by spin-coating method. Linear optical absorption measurements of the Au/PVP composite films indicate an absorption peak around 530 nm due to the surface plasmon resonance of gold nanoparticles. Nonlinear optical properties are studied using standard Z-scan technique, and experimental results show large optical nonlinearities of the Au/PVP composite films. A large value of films.

  5. High Performance Thin-Film Composite Forward Osmosis Membrane

    KAUST Repository

    Yip, Ngai Yin

    2010-05-15

    Recent studies show that osmotically driven membrane processes may be a viable technology for desalination, water and wastewater treatment, and power generation. However, the absence of a membrane designed for such processes is a significant obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation onto a thin (40 μm) polyester nonwoven fabric. By careful selection of the polysulfone casting solution (i.e., polymer concentration and solvent composition) and tailoring the casting process, we produced a support layer with a mix of finger-like and sponge-like morphologies that give significantly enhanced membrane performance. The structure and performance of the new thin-film composite forward osmosis membrane are compared with those of commercial membranes. Using a 1.5 M NaCl draw solution and a pure water feed, the fabricated membranes produced water fluxes exceeding 18 L m2-h-1, while consistently maintaining observed salt rejection greater than 97%. The high water flux of the fabricated thin-film composite forward osmosis membranes was directly related to the thickness, porosity, tortuosity, and pore structure of the polysulfone support layer. Furthermore, membrane performance did not degrade after prolonged exposure to an ammonium bicarbonate draw solution. © 2010 American Chemical Society.

  6. Thin film composite nanofiltration membranes for extreme conditions

    NARCIS (Netherlands)

    Dalwani, Mayur Ramesh

    2011-01-01

    The research presented in this thesis focuses on development and performance evaluation of thin film composite (TFC) nanofiltration (NF) membranes, with special attention to extreme pH applications. In Chapter 2 a new method that allows molecular weight cut off (MWCO) characterization of NF membran

  7. Thin Film Polymer Composite Scintillators for Thermal Neutron Detection

    Directory of Open Access Journals (Sweden)

    Andrew N. Mabe

    2013-01-01

    Full Text Available Thin film polystyrene composite scintillators containing LiF6 and organic fluors have been fabricated and tested as thermal neutron detectors. Varying fluorescence emission intensities for different compositions are interpreted in terms of the Beer-Lambert law and indicate that the sensitivity of fluorescent sensors can be improved by incorporating transparent particles with refractive index different than that of the polymer matrix. Compositions and thicknesses were varied to optimize the fluorescence and thermal neutron response and to reduce gamma-ray sensitivity. Neutron detection efficiency and neutron/gamma-ray discrimination are reported herein as functions of composition and thickness. Gamma-ray sensitivity is affected largely by changing thickness and unaffected by the amount of LiF6 in the film. The best neutron/gamma-ray discrimination characteristics are obtained for film thicknesses in the range 25–150 μm.

  8. Zeta-potential of fouled thin film composite membrane

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, K.; Hachisuka, H.; Nakamura, T. [Nitto denko Corp., Ibaraki, (Japan); Kimura, S. [Kogakuin University, Tokyo (Japan). Dept. of Environ. Chemical Engineering; Ueyama, K. [Osaka University, Osaka (Japan). Dept. of Chemical Engineering

    1999-10-01

    The surface zeta-potential of a cross-linked polyamide thin film composite reverse osmosis membrane was measured using an electrophoresis method. It was confirmed that this method could be effectively applied to analyze the fouling of such membranes. It is known that the water flux of membranes drastically decreases as a result of fouling by surfactants. Although the surfactants adsorbed on reverse osmosis membranes could not be detected by conventional methods such as SEM, EDX and FT-IR, their presence could be clarified by the profile measurements of the surface zeta-potential. The profiles of the membrane surface zeta-potentials changed to more positive values in the measured pH range as a result of fouling by cationic or amphoteric surfactants. This measuring method of surface zeta-potentials allowed us to analyze a very small amount of fouling of a thin film composite reverse osmosis membrane. This method could be used to analyze the fouled surface of the thin film composite reverse osmosis membrane which is used for production of ultrapure water and shows a remarkable decrease in flux. It also became clear that this method is easy and effective for the reverse osmosis membrane surface analysis of adsorbed materials such as surfactants. (author)

  9. Magnetic coupling mechanisms in particle/thin film composite systems

    Directory of Open Access Journals (Sweden)

    Giovanni A. Badini Confalonieri

    2010-12-01

    Full Text Available Magnetic γ-Fe2O3 nanoparticles with a mean diameter of 20 nm and size distribution of 7% were chemically synthesized and spin-coated on top of a Si-substrate. As a result, the particles self-assembled into a monolayer with hexagonal close-packed order. Subsequently, the nanoparticle array was coated with a Co layer of 20 nm thickness. The magnetic properties of this composite nanoparticle/thin film system were investigated by magnetometry and related to high-resolution transmission electron microscopy studies. Herein three systems were compared: i.e. a reference sample with only the particle monolayer, a composite system where the particle array was ion-milled prior to the deposition of a thin Co film on top, and a similar composite system but without ion-milling. The nanoparticle array showed a collective super-spin behavior due to dipolar interparticle coupling. In the composite system, we observed a decoupling into two nanoparticle subsystems. In the ion-milled system, the nanoparticle layer served as a magnetic flux guide as observed by magnetic force microscopy. Moreover, an exchange bias effect was found, which is likely to be due to oxygen exchange between the iron oxide and the Co layer, and thus forming of an antiferromagnetic CoO layer at the γ-Fe2O3/Co interface.

  10. The effective flux through a thin-film composite membrane

    Science.gov (United States)

    Bruna, M.; Chapman, S. J.; Ramon, G. Z.

    2015-05-01

    Composite membrane structures, used extensively in separation processes, comprise an ultra-thin selective polymer film cast over a porous support, whose pores partially obstruct transport out of the top film. Here, we model the composite as a finite thickness slab with a periodic array of circular absorbing patches in an otherwise reflective surface and study the effective transport properties of the composite. We obtain an analytical approximation for the effective diffusive flux as a function of the geometrical parameters, namely the film thickness, the support porosity and the pore size. We find a good agreement with full numerical solutions, and that a good effective rate is achievable with a relatively small number of pores.

  11. Thin film composition with biological substance and method of making

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Allison A. (Kennewick, WA); Song, Lin (Richland, WA)

    1999-01-01

    The invention provides a thin-film composition comprising an underlying substrate of a first material including a plurality of attachment sites; a plurality of functional groups chemically attached to the attachment sites of the underlying substrate; and a thin film of a second material deposited onto the attachment sites of the underlying substrate, and a biologically active substance deposited with the thin-film. Preferably the functional groups are attached to a self assembling monolayer attached to the underlying substrate. Preferred functional groups attached to the underlying substrate are chosen from the group consisting of carboxylates, sulfonates, phosphates, optionally substituted, linear or cyclo, alkyl, alkene, alkyne, aryl, alkylaryl, amine, hydroxyl, thiol, silyl, phosphoryl, cyano, metallocenyl, carbonyl, and polyphosphate. Preferred materials for the underlying substrate are selected from the group consisting of a metal, a metal alloy, a plastic, a polymer, a proteic film, a membrane, a glass or a ceramic. The second material is selected from the group consisting of inorganic crystalline structures, inorganic amorphus structures, organic crystalline structures, and organic amorphus structures. Preferred second materials are phosphates, especially calcium phosphates and most particularly calcium apatite. The biologically active molecule is a protein, peptide, DNA segment, RNA segment, nucleotide, polynucleotide, nucleoside, antibiotic, antimicrobal, radioisotope, chelated radioisotope, chelated metal, metal salt, anti-inflamatory, steriod, nonsteriod anti-inflammatory, analgesic, antihistamine, receptor binding agent, or chemotherapeutic agent, or other biologically active material. Preferably the biologically active molecule is an osteogenic factor the compositions listed above.

  12. Thin film composition with biological substance and method of making

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, A.A.; Song, L.

    1999-09-28

    The invention provides a thin-film composition comprising an underlying substrate of a first material including a plurality of attachment sites; a plurality of functional groups chemically attached to the attachment sites of the underlying substrate; and a thin film of a second material deposited onto the attachment sites of the underlying substrate, and a biologically active substance deposited with the thin-film. Preferably the functional groups are attached to a self assembling monolayer attached to the underlying substrate. Preferred functional groups attached to the underlying substrate are chosen from the group consisting of carboxylates, sulfonates, phosphates, optionally substituted, linear or cyclo, alkyl, alkene, alkyne, aryl, alkylaryl, amine, hydroxyl, thiol, silyl, phosphoryl, cyano, metallocenyl, carbonyl, and polyphosphate. Preferred materials for the underlying substrate are selected from the group consisting of a metal, a metal alloy, a plastic, a polymer, a proteic film, a membrane, a glass or a ceramic. The second material is selected from the group consisting of inorganic crystalline structures, inorganic amorphous structures, organic crystalline structures, and organic amorphous structures. Preferred second materials are phosphates, especially calcium phosphates and most particularly calcium apatite. The biologically active molecule is a protein, peptide, DNA segment, RNA segment, nucleotide, polynucleotide, nucleoside, antibiotic, antimicrobial, radioisotope, chelated radioisotope, chelated metal, metal salt, anti-inflammatory, steroid, nonsteroid anti-inflammatory, analgesic, antihistamine, receptor binding agent, or chemotherapeutic agent, or other biologically active material. Preferably the biologically active molecule is an osteogenic factor consisting of the compositions listed above.

  13. Structural mechanics and helical geometry of thin elastic composites.

    Science.gov (United States)

    Wada, Hirofumi

    2016-09-21

    Helices are ubiquitous in nature, and helical shape transition is often observed in residually stressed bodies, such as composites, wherein materials with different mechanical properties are glued firmly together to form a whole body. Inspired by a variety of biological examples, the basic physical mechanism responsible for the emergence of twisting and bending in such thin composite structures has been extensively studied. Here, we propose a simplified analytical model wherein a slender membrane tube undergoes a helical transition driven by the contraction of an elastic ribbon bound to the membrane surface. We analytically predict the curvature and twist of an emergent helix as functions of differential strains and elastic moduli, which are confirmed by our numerical simulations. Our results may help understand shapes observed in different biological systems, such as spiral bacteria, and could be applied to novel designs of soft machines and robots.

  14. Nanodiamond-polymer nanoparticle composites and their thin films

    Science.gov (United States)

    Attia, N. F.; Rao, J. P.; Geckeler, K. E.

    2014-04-01

    Nanodiamonds obtained from detonation processes have received a great deal of attention during the past decades because of their unique properties and applications. The dispersion of nanodiamond particles can be achieved by different methods including the use of polymer nanoparticles. Here, we describe the dispersion of nanodiamonds in conjunction with sonication using poly(vinylpyrrolidone) nanoparticles with a particle size range of 23.3-61.3 nm, providing a good, economic, and efficient method for the dispersion. The average particle size was found to be 37.5 nm, as confirmed by transmission electron microscopy. The interaction between the nanodiamonds and polymer nanoparticles was characterized by FTIR spectroscopy and the effect of the polymer nanoparticle concentration, sonication time, and frequency on the dispersion process of nanodiamonds is highlighted. In addition, we prepared thin films of nanodiamond-polymer composites with different nanodiamond contents that showed good nanodiamond dispersion. The thin film can act as a UV filter and is transparent in the visible region. The thin films of nanodiamond-poly(vinylpyrrolidone) nanoparticles were characterized by SEM and UV-Vis spectroscopy.

  15. Silver nanowire composite thin films as transparent electrodes for Cu(In,Ga)Se₂/ZnS thin film solar cells.

    Science.gov (United States)

    Tan, Xiao-Hui; Chen, Yu; Liu, Ye-Xiang

    2014-05-20

    Solution processed silver nanowire indium-tin oxide nanoparticle (AgNW-ITONP) composite thin films were successfully applied as the transparent electrodes for Cu(In,Ga)Se₂ (CIGS) thin film solar cells with ZnS buffer layers. Properties of the AgNW-ITONP thin film and its effects on performance of CIGS/ZnS thin film solar cells were studied. Compared with the traditional sputtered ITO electrodes, the AgNW-ITONP thin films show comparable optical transmittance and electrical conductivity. Furthermore, the AgNW-ITONP thin film causes no physical damage to the adjacent surface layer and does not need high temperature annealing, which makes it very suitable to use as transparent conductive layers for heat or sputtering damage-sensitive optoelectronic devices. By using AgNW-ITONP electrodes, the required thickness of the ZnS buffer layers for CIGS thin film solar cells was greatly decreased.

  16. Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

    OpenAIRE

    Rackel Reis; Dumée, Ludovic F.; Tardy, Blaise L.; Raymond Dagastine; John D. Orbell; Jürg A. Schutz; Duke, Mikel C.

    2016-01-01

    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membra...

  17. Finite element simulations of thin-film composite BAW resonators.

    Science.gov (United States)

    Makkonen, T; Holappa, A; Ellä, J; Salomaa, M M

    2001-09-01

    A finite element method (FEM) formulation is presented for the numerical solution of the electroelastic equations that govern the linear forced vibrations of piezoelectric media. A harmonic time dependence is assumed. Both of the approaches, that of solving the field problem (harmonic analysis) and that of solving the corresponding eigenvalue problem (modal analysis), are described. A FEM software package has been created from scratch. Important aspects central to the efficient implementation of FEM are explained, such as memory management and solving the generalized piezoelectric eigenvalue problem. Algorithms for reducing the required computer memory through optimization of the matrix profile, as well as Lanczos algorithm for the solution of the eigenvalue problem are linked into the software from external numerical libraries. Our FEM software is applied to detailed numerical modeling of thin-film bulk acoustic wave (BAW) composite resonators. Comparison of results from 2D and full 39 simulations of a resonator are presented. In particular, 3D simulations are used to investigate the effect of the top electrode shape on the resonator electrical response. The validity of the modeling technique is demonstrated by comparing the simulated and measured displacement profiles at several frequencies. The results show that useful information on the performance of the thin-film resonators can be obtained even with relatively coarse meshes and, consequently, moderate computational resources.

  18. Using thin metal layers on composite structures for shielding the electromagnetic pulse caused by nearby lightning

    NARCIS (Netherlands)

    Blaj, M.A.; Buesink, F.J.K.; Damstra, G.C.; Leferink, F.B.J.

    2011-01-01

    Electronic systems in composite structures could be vulnerable to the (dominant magnetic) field caused by a lightning strike, because only thin layers of metal can be used on composite structures. Thin layers result in a very low shielding effectiveness against magnetic fields. Many experiments usin

  19. One-step synthesis of PbSe-ZnSe composite thin film

    OpenAIRE

    2011-01-01

    Abstract This study investigates the preparation of PbSe-ZnSe composite thin films by simultaneous hot-wall deposition (HWD) from multiple resources. The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films. A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix. The optical absorption edge of the composite thin...

  20. Thin Film Heat Flux Sensor Development for Ceramic Matrix Composite (CMC) Systems

    Science.gov (United States)

    Wrbanek, John D.; Fralick, Gustave C.; Hunter, Gary W.; Zhu, Dongming; Laster, Kimala L.; Gonzalez, Jose M.; Gregory, Otto J.

    2010-01-01

    The NASA Glenn Research Center (GRC) has an on-going effort for developing high temperature thin film sensors for advanced turbine engine components. Stable, high temperature thin film ceramic thermocouples have been demonstrated in the lab, and novel methods of fabricating sensors have been developed. To fabricate thin film heat flux sensors for Ceramic Matrix Composite (CMC) systems, the rough and porous nature of the CMC system posed a significant challenge for patterning the fine features required. The status of the effort to develop thin film heat flux sensors specifically for use on silicon carbide (SiC) CMC systems with these new technologies is described.

  1. Composition, Constitution and Phase Transformation Behavior in Thin-Film and Bulk Ti-Ni-Y

    Science.gov (United States)

    König, D.; Frowein, P.; Wieczorek, A.; Frenzel, J.; Hamann, S.; Eggeler, G.; Ludwig, A.

    2017-01-01

    Advanced engineering applications require new and improved shape memory alloys in bulk and thin-film form. While many Ti-Ni-based systems have been studied so far, the Ti-Ni-Y materials system was not studied in detail concerning its bulk and thin-film shape memory properties. For this reason, a Ti-Ni-Y thin-film materials library focussing on compositions close to Ni50Ti50 was fabricated by combinatorial magnetron sputtering. This library was characterized by high-throughput methods and the compositional range where phase transformations occur was identified. Ti-Ni-Y thin films exhibit a very narrow hysteresis width ∆T and allow to precisely adjust ∆T. Based on the promising results of Ti-Ni-Y thin films, which can be directly applied in microsystems, bulk alloys were fabricated in order to explore how thin-film and bulk properties of different Ti-Ni-Y compositions correlate. It turned out that Ti-Ni-Y bulk materials show different phase transformation properties compared to thin films, most importantly higher ∆T. The differences between thin-film and bulk material are discussed.

  2. Composition, Constitution and Phase Transformation Behavior in Thin-Film and Bulk Ti-Ni-Y

    Science.gov (United States)

    König, D.; Frowein, P.; Wieczorek, A.; Frenzel, J.; Hamann, S.; Eggeler, G.; Ludwig, A.

    2017-03-01

    Advanced engineering applications require new and improved shape memory alloys in bulk and thin-film form. While many Ti-Ni-based systems have been studied so far, the Ti-Ni-Y materials system was not studied in detail concerning its bulk and thin-film shape memory properties. For this reason, a Ti-Ni-Y thin-film materials library focussing on compositions close to Ni50Ti50 was fabricated by combinatorial magnetron sputtering. This library was characterized by high-throughput methods and the compositional range where phase transformations occur was identified. Ti-Ni-Y thin films exhibit a very narrow hysteresis width ∆ T and allow to precisely adjust ∆ T. Based on the promising results of Ti-Ni-Y thin films, which can be directly applied in microsystems, bulk alloys were fabricated in order to explore how thin-film and bulk properties of different Ti-Ni-Y compositions correlate. It turned out that Ti-Ni-Y bulk materials show different phase transformation properties compared to thin films, most importantly higher ∆ T. The differences between thin-film and bulk material are discussed.

  3. Separation of Hydrogen Using an Electroless Deposited Thin-Film Palladium-Ceramic Composite Membrane

    Energy Technology Data Exchange (ETDEWEB)

    Ilias, S.; King, F.G.; Fan, Ting-Fang; Roy, S. [North Carolina Agricultural and Technical State Univ., Greensboro, NC (United States). Dept. of Chemical Engineering

    1996-12-31

    The primary objective of this project was to prepare and characterize a hydrogen permselective palladium-ceramic composite membrane for high temperature gas separations and catalytic membrane reactors. Electroless plating method was used to deposit a thin palladium film on microporous ceramic substrate. The objective of this paper is to discuss the preparation and characterization of a thin-film palladium-ceramic composite membrane for selective separation of hydrogen at elevated temperatures and pressures. In this paper, we also present a model to describe the hydrogen transport through the palladium-ceramic composite membrane in a cocurrent flow configuration.

  4. One-step synthesis of PbSe-ZnSe composite thin film

    Science.gov (United States)

    2011-01-01

    This study investigates the preparation of PbSe-ZnSe composite thin films by simultaneous hot-wall deposition (HWD) from multiple resources. The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films. A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix. The optical absorption edge of the composite thin films shifts toward the low-photon-energy region as the PbSe content increases. The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package. PMID:21711822

  5. One-step synthesis of PbSe-ZnSe composite thin film

    Directory of Open Access Journals (Sweden)

    Abe Seishi

    2011-01-01

    Full Text Available Abstract This study investigates the preparation of PbSe-ZnSe composite thin films by simultaneous hot-wall deposition (HWD from multiple resources. The XRD result reveals that the solubility limit of Pb in ZnSe is quite narrow, less than 1 mol%, with obvious phase-separation in the composite thin films. A nanoscale elemental mapping of the film containing 5 mol% PbSe indicates that isolated PbSe nanocrystals are dispersed in the ZnSe matrix. The optical absorption edge of the composite thin films shifts toward the low-photon-energy region as the PbSe content increases. The use of a phase-separating PbSe-ZnSe system and HWD techniques enables simple production of the composite package.

  6. Preparation and photochromism of Keggin-type molybdphosphoric acid/silica mesoporous composite thin films

    Institute of Scientific and Technical Information of China (English)

    ZHANG XueAo; WU WenJian; MAN YaHui; TIAN Tian; TIAN XiaoZhou; WANG JianFang

    2007-01-01

    Using tetraethoxysilane and 3-aminopropyltriethoxysilane as the silica sources, amino-functionalized organic/inorganic hybrid mesoporous silica thin films with 2-dimensional hexagonal structure have been synthesized by evaporation induced self-assembly process in the presence of cetyltrimethyl ammonium bromide templates under acid conditions. The Keggin-type molybdphosphoric acid (PMo) is incorporated into the mesoporous silica thin films with amino-groups by wetness impregnation, and the PMo/silica mesoporous composite thin films are obtained. The results of X-ray diffraction (XRD),high resolution transmission electron microscopy (HRTEM), and Fourier transform infrared (FTIR)spectra indicate the PMo molecules maintain Keggin structure and are homogeneously distributed inside mesopores. The composite thin films possess excellent reversible photochromic properties, and change from colorless to blue under ultraviolet irradiation. The photochromic mechanism of the composite thin films is studied by ultraviolet-visible (UV-vis), electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS) spectra. It is shown that intervalence charge transfer (IVCT) and ligand-to-metal charge transfer (LMCT) are the main reasons of photochromism. PMo anions interact strongly with amino-groups of the mesoporous suface via hydrogen bond and electrostatic force. After ultraviolet irradiation, the charge transfer occurs by reduction of heteropolyanions accompanying the formation of heteropolyblues with multivalence Mo(Ⅵ, Ⅴ), and the bleaching process of composite thin films is closely related to the presence of oxygen.

  7. Preparation and photochromism of Keggin-type molybdphosphoric acid/silica mesoporous composite thin films

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Using tetraethoxysilane and 3-aminopropyltriethoxysilane as the silica sources, amino-functionalized organic/inorganic hybrid mesoporous silica thin films with 2-dimensional hexagonal structure have been synthesized by evaporation induced self-assembly process in the presence of cetyltrimethyl ammonium bromide templates under acid conditions. The Keggin-type molybdphosphoric acid (PMo) is incorporated into the mesoporous silica thin films with amino-groups by wetness impregnation, and the PMo/silica mesoporous composite thin films are obtained. The results of X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and Fourier transform infrared (FTIR) spectra indicate the PMo molecules maintain Keggin structure and are homogeneously distributed inside mesopores. The composite thin films possess excellent reversible photochromic properties, and change from colorless to blue under ultraviolet irradiation. The photochromic mechanism of the composite thin films is studied by ultraviolet-visible (UV-vis), electron spin resonance (ESR) and X-ray photoelectron spectroscopy (XPS) spectra. It is shown that intervalence charge transfer (IVCT) and ligand-to-metal charge transfer (LMCT) are the main reasons of photochromism. PMo anions interact strongly with amino-groups of the mesoporous suface via hydrogen bond and electrostatic force. After ultraviolet irradiation, the charge transfer occurs by reduction of heteropolyanions accompanying the formation of heteropolyblues with multivalence Mo(VI, V), and the bleaching process of composite thin films is closely related to the presence of oxygen.

  8. Thermally stimulated discharge conductivity in polymer composite thin films

    Indian Academy of Sciences (India)

    V S Sangawar; P S Chikhalikar; R J Dhokne; A U Ubale; S D Meshram

    2006-08-01

    This paper describes the results of thermally stimulated discharge conductivity study of activated charcoal–polyvinyl chloride (PVC) thin film thermoelectrets. TSDC has been carried out in the temperature range 308–400°K and at four different polarizing fields. Results are discussed on the basis of mobility of activated charcoal and polyvinyl chloride chains.

  9. Effects of thinning on plant species diversity and composition of understory herbs in a larch plantation

    Institute of Scientific and Technical Information of China (English)

    Jiaojun ZHU; Zhihong MAO; Caihong ZHANG; Qiaoling YAN; Zugen LIU

    2008-01-01

    The effects of thinning on plant species diversity and composition of understory herbs in a larch plantation were investigated. The relationships between plant species diversity and composition of understory herbs and light conditions were established. Twenty-five 1 m × 1 m plots and fifteen 13 m × 1 m transects were set up in unthinned and thinned stands, respectively. All the transects in the thinned stands were set across the thinned rows and unthinned rows, and each of them was divided into nine 1 m × 1 m sub-plots. The herb diversity and light condi-tions were observed in each plot and sub-plot. The results show that there was a significant difference in herb diversity between the thinned and unthinned stands. All biodiversity indices except for evenness index in the thinned stand were higher than those of the unthinned stand, i.e., the herb diversity increased after thinning. According to the changes in herb densities and whether one species could be found in a stand or not before and after thinning, all herb species were classed into three types: positive, neutral and negative species, which referred to a species newly appeared and having an obviously increased density after thinning, with no obvious changes in its appearance and density after thin-ning, and disappeared and having an obviously decreased density after thinning, respectively. Many new species were found in the thinned stand like Corydalis pallida, Prenanthes tatarinowii, Vicia unijuga and Sonchus brachyotus etc. However, most species found in both the thinned and unthinned stands were negative species. In all nine sub-plots, only 11 and 10 species were found in spring and in autumn respectively, accounting for 17.74% and 15.15% of all the species in the thinned stand, respectively. All biodiversity indices were the highest in the center sub-plots and most of them tended to reduce from middle to side sub-plots. There was a close correlation between most of the three types of species and

  10. Pulsed laser deposition of carbon nanotube and polystyrene-carbon nanotube composite thin films

    Science.gov (United States)

    Stramel, A. A.; Gupta, M. C.; Lee, H. R.; Yu, J.; Edwards, W. C.

    2010-12-01

    In this work, we report on the fabrication of carbon nanotube thin films via pulsed laser deposition using a pulsed, diode pumped, Tm:Ho:LuLF laser with 2 μm wavelength. The thin films were deposited on silicon substrates using pure carbon nanotube targets and polystyrene-carbon nanotube composite targets. Raman spectra, scanning electron micrographs, and transmission electron micrographs show that carbon nanotubes are present in the deposited thin films, and that the pulsed laser deposition process causes minimal degradation to the quality of the nanotubes when using pure carbon nanotube targets.

  11. Anomalous hopping conduction in nanocrystalline/amorphous composites and amorphous semiconductor thin films

    Science.gov (United States)

    Kakalios, James; Bodurtha, Kent

    Composite nanostructured materials consisting of nanocrystals (nc) embedded within a thin film amorphous matrix can exhibit novel opto-electronic properties. Composite films are synthesized in a dual-chamber co-deposition PECVD system capable of producing nanocrystals of material A and embedding then within a thin film matrix of material B. Electronic conduction in composite thin films of hydrogenated amorphous silicon (a-Si:H) containing nc-germanium or nc-silicon inclusions, as well as in undoped a-Si:H, does not follow an Arrhenius temperature dependence, but rather is better described by an anomalous hopping expression (exp[-(To/T)3/4) , as determined from the ``reduced activation energy'' proposed by Zabrodskii and Shlimak. This temperature dependence has been observed in other thin film resistive materials, such as ultra-thin disordered films of Ag, Bi, Pb and Pd; carbon-black polymer composites; and weakly coupled Au and ZnO quantum dot arrays. There is presently no accepted theoretical understanding of this expression. The concept of a mobility edge, accepted for over four decades, appears to not be necessary to account for charge transport in amorphous semiconductors. Supported by NSF-DMR and the Minnesota Nano Center.

  12. Layered TiO2: PVK nano-composite thin films for photovoltaic applications. TiO2: PVK nano-composite thin films.

    Science.gov (United States)

    Kaune, G; Wang, W; Metwalli, E; Ruderer, M; Rossner, R; Roth, S V; Müller-Buschbaum, P

    2008-01-01

    The influence of the solvent used for spin-coating on the homogeneity of poly(N-vinylcarbazole) (PVK) films is investigated. Homogenous films are obtained only by the use of toluene, solution in tetrahydrofuran (THF) and chloroform results in radially oriented inhomogeneities and films prepared by use of N-methylpyrrolidone and dimethylacetamide show particle formation during spin-coating. Layered nano-composite thin films are prepared by spin-coating a PVK film on top of a nano-structured titanium dioxide ( TiO2) layer. The TiO2 thin films are prepared by a sol-gel process using an amphiphilic copolymer as structure-directing agent. Structural characterisation of the TiO2 :PVK nano-composite films is done by field emission scanning electron microscopy (FESEM) and grazing-incidence small-angle scattering (GISAXS). Bare TiO2 films are probed for comparison. Light is basically only absorbed in the ultraviolet regime and absorption slightly increases upon addition of PVK, which makes the layered TiO2 :PVK nano-composite thin films good candidates for UV photovoltaic devices. Furthermore, absorption remains stable over a period of several days.

  13. Structure and composition effects on electrical and optical properties of sputtered PbSe thin films

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xigui; Gao, Kewei [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Pang, Xiaolu, E-mail: pangxl@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Yang, Huisheng [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Volinsky, Alex A. [Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620 (United States)

    2015-10-01

    Lead selenide (PbSe) thin films were grown on Si (111) substrates using magnetron sputtering, and the structure and composition effects on the photoelectric and optical properties of the sputtered PbSe thin films were studied using field emission scanning electron microscope, energy dispersive X-ray detector, X-ray diffraction, X-ray photoelectron spectroscopy, physical property measurement system and Fourier transform infrared spectroscopy. The optical band gaps of all the sputtered PbSe thin films ranged from 0.264 eV to 0.278 eV. The PbSe thin film prepared with oxygen flux 1.0 sccm, deposition time 240 min, sputtering power 150 W and substrate temperature 150 °C showed the highest resistance change rate under illumination, about 84.47%. The variation trends of the photoelectric and optical properties with the average crystal size, lattice constant, oxygen content and lattice oxygen percentage were similar, respectively. The sputtered PbSe thin films showed poor photoelectric sensitivity, when the average crystal size was similar to the Bohr radius (46 nm), while the photoelectric sensitivity increased almost linearly with the oxygen content in the thin films, indicating that both deviating the average crystal size from the Bohr radius and increasing the oxygen content are two direct and effective ways to obtain high photoelectric sensitivity in PbSe thin films. - Highlights: • Lead selenide thin films were grown on Si (111) using magnetron sputtering. • Lead selenide thin films show superior photoelectric sensitivity. • The effects of structure and composition to the film properties were studied. • The photoelectric property was mainly affected by grain size and oxygen content.

  14. CHEMICAL COMPOSITION OF EUCALIPT WOOD WITH DIFFERENT LEVELS OF THINNING

    Directory of Open Access Journals (Sweden)

    Antônio José Vinha Zanuncio

    2013-12-01

    Full Text Available http://dx.doi.org/10.5902/1980509812359The objective of this study was to evaluate different thinning regimes in forest plantations of eucalypt(Eucalyptus grandis x Eucalyptus urophylla clones to produce timber for cellulose and charcoal to verifywhether this effect could affect the proportion of the chemical components of wood. The average initialspacing between plants was 3x3 m and the treatments were: T1= control, T2, T3and T4 with thinning 20%,35% and 50% of the basal area, respectively. The results were analyzed by Tukey test at 5% probability.According to the results found the lignin content from treatment T4 was higher than that of the others; thegroups of uronic acids of the T1 was similar to all other treatments, but the levels of T2 and T4 differedbetween them. The extractives content of T1was similar to the T2 and T3 and lower than that of theT4; thecarbohydrates of T1 were similar to that of T3 and higher than the others. It was concluded that thinningincreases the quality of the wood to be used as energy purposes, such as charcoal production, but it did notincrease productivity for wood pulp and paper production.

  15. Residual stress in composites with the thin-ring-slitting approach.

    Science.gov (United States)

    Park, J W; Ferracane, J L

    2006-10-01

    During polymerization, dental composites develop residual stresses that may compromise the marginal integrity and properties of the restorative. The objective of this study was to use the thin-walled ring-slitting method to measure and compare residual stresses. The hypotheses to be tested were that composites would generate different levels of residual stress based on their specific formulations and slitting times. Rings made from composites (Z100, Herculite, and Heliomolar) were cut at different times (10 min, 1 and 24 hrs) after being light-cured, and stress was measured. Residual stress was higher at the earlier cutting times, except for Heliomolar (alpha stress followed this order: Z100 > Herculite > Heliomolar. Early slitting was better to capture residual stress, and the thin-walled rings showed higher values than thick-walled rings and were better able to discriminate residual stress in composites.

  16. Methods of making copper selenium precursor compositions with a targeted copper selenide content and precursor compositions and thin films resulting therefrom

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); van Hest, Marinus Franciscus Antonius Maria (Lakewood, CO); Ginley, David S. (Evergreen, CO); Leisch, Jennifer (Denver, CO); Taylor, Matthew (West Simsbury, CT); Stanbery, Billy J. (Austin, TX)

    2011-09-20

    Precursor compositions containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semi-conductor applications. Methods of forming the precursor compositions using primary amine solvents and methods of forming the thin films wherein the selection of temperature and duration of heating controls the formation of a targeted species of copper selenide.

  17. Effect of substrate temperature on microstructures and dielectric properties of compositionally graded BST thin films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bai-shun; GUO Tao; ZHANG Tian-jin; WANG Jin-zhao; QUAN Zu-ci

    2006-01-01

    Compositionally graded Ba1-xSrxTiO3 (BST) (x = 0-0.3) thin films were prepared on Pt/Ti/SiO2/Si substrate at different substrate temperatures ranging from 550 ℃ to 650 ℃ by radio-frequency (rf) magnetron sputtering. The effect of substrate temperature on the preferential orientation,microstructures and dielectric properties of compositionally graded BST thin films was investigated by X-ray diffraction,scanning electron microscopy and dielectric frequency spectra,respectively. As the temperature increases,the preferential orientation evolves in the order: randomly orientation→ (111) → highly oriented (111) (α(111) = 60.2%). The surface roughness of the graded BST thin films varies with the substrate temperatures. No visible internal interface in the compositionally graded thin films can be observed in the cross-sectional SEM images. The graded BST thin films deposited at 650 ℃ possess the highest dielectric constant and dielectric loss,which are 408 and 0.013,respectively.

  18. Characterization of LiFePO4/C Composite Thin Films Using Electrochemical Impedance Spectroscopy

    Science.gov (United States)

    Bajars, G.; Kucinskis, G.; Smits, J.; Kleperis, J.; Lusis, A.

    2012-08-01

    The composite LiFePO4/C thin films were prepared on steel substrate by radio frequency (RF) magnetron sputtering. Electrochemical properties of the obtained thin films were investigated by cyclic voltammetry charge-discharge measurements and electrochemical impedance spectroscopy (EIS). The films annealed at 550 °C exhibited a couple of redox peaks at 3.45 V vs. Li/Li+ characteristic for the electrochemical lithium insertion/extraction in LiFePO4. At low current rate such composite thin film showed a discharge capacity of over 110 mAh g-1. The dependence of charge transfer resistance, double layer capacitance and lithium diffusion coefficients on applied electrode potential were calculated from EIS data. Determined values of lithium diffusion coefficient were in the range from 8.3-10-13 cm2 s1 to 1.2-10-13 cm2 s-1 at 3.4 V and 3.7 V, respectively.

  19. Fabrication and biocompatibility in vitro of potassium titanate biological thin film/titanium alloy biological composite

    Institute of Scientific and Technical Information of China (English)

    QI Yumin; HE Yun; CUI Chunxiang; LIU Shuangjin; WANG Huifen

    2007-01-01

    A potassium titanate biological thin film/titanium alloy biological composite was fabricated by way of bionic chemistry.The biocompatibility fn vitro of Ti-15Mo-3Nb and the potassium titanate biological thin film/titanium alloy was studied using simulated body fluid cultivation,kinetic clotting of blood and osteoblast cell cultivation experiments in vitro.By comparing the biological properties of both materials,the following conclusions can be obtained:(1)The deposition of a calcium phosphate layer was not found on the surface of Ti-15Mo-3Nb,so it was bioinert.Because the network of potassium titanate biological thin film could induce the deposition of a calcium phosphate layer,this showed that it had excellent bioactivity.(2)According to the values of kinetic clotting,the blood coagulation time of the potassium titanate biological thin film was more than that of Ti-15Mo-3Nb.It was obvious that the potassium titanate biological thin film possessed good hemocompatibility.(3)The cell compatibility of both materials was very good.However,the growth trend and multiplication of osteoblast cells on the surface of potassium titanate biological thin film was better,which made for the concrescence of wounds during the earlier period.As a result,the potassium titanate biological thin film/titanium alloy showed better biocompatibility and bioactivity.

  20. Nonlinear dynamics of angle-ply composite laminated thin plate with third-order shear deformation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    An asymptotic perturbation method is presented based on the Fourier expansion and temporal rescaling to investigate the nonlinear oscillations and chaotic dynamics of a simply supported angle-ply composite laminated rectangular thin plate with parametric and external excitations.According to the Reddy’s third-order plate theory,the governing equations of motion for the angle-ply composite laminated rectangular thin plate are derived by using the Hamilton’s principle.Then,the Galerkin procedure is applied to the partial differential governing equation to obtain a two-degrees-of-freedom nonlinear system including the quadratic and cubic nonlinear terms.Such equations are utilized to deal with the resonant case of 1:1 internal resonance and primary parametric resonance-1/2 subharmonic resonance.Furthermore,the stability analysis is given for the steady-state solutions of the averaged equation.Based on the averaged equation obtained by the asymptotic perturbation method,the phase portrait and power spectrum are used to analyze the multi-pulse chaotic motions of the angle-ply composite laminated rectangular thin plate.Under certain conditions the various chaotic motions of the angle-ply composite laminated rectangular thin plate are found.

  1. Exploring the structure-properties relationships of novel polyamide thin film composite membranes

    DEFF Research Database (Denmark)

    Briceño, Kelly; Javakhishvili, Irakli; Guo, Haofei

    Polysulfone (PSU) is a material widely used in the fabrication of membranes for ultrafiltration and as a support for nanofiltration and reverse osmosis membranes. Interfacial polymerization usually combines amine and acid chloride monomers for the fabrication of thin film composite membranes[1...

  2. Vibration analysis of magnetostrictive thin-film composite cantilever actuator

    Science.gov (United States)

    Xu, Yan; Shang, Xinchun

    2016-09-01

    The transverse vibration of a composed cantilever beam with magnetostrictive layer is analyzed, which is employed to simulate dynamic response of an actuator. The high-order shear deformation theory of beam and the coupling magnetoelastic constitutive relationship are introduced to construct the governing equations, all interface conditions between magnetostrictive film and elastic substrate as well as the free stress condition on the top and bottom surfaces of the beam can be satisfied. In order to demonstrate validity of the presented mathematical modeling, the verification examples are also given. Furthermore, the effect of geometry and material parameters on dynamic characteristics of magnetostrictive cantilever beam, such as the nature frequency and amplitude, is discussed. Moreover, through computing the magneto-mechanical coupling factor of the beam structure, the variation tendency curves of the factor along with different parameters and frequencies of magnetostrictive cantilever beam actuator have been presented. These numerical results should be useful for the design of beam-type with magnetostrictive thin-film actuators.

  3. Structure and surface composition of NiCr sputtered thin films

    Directory of Open Access Journals (Sweden)

    Petrović S.

    2006-01-01

    Full Text Available Thin films of nichrome were deposited by d.c. sputtering of a target (80%Ni 20%Cr w.t by Ar+ions at a working pressure of 10-1 Pa and at room temperature. The phase composition and grain size were studied by X-ray Diffraction (XRD, while the surface chemical composition was determined by Low Energy Ion Scattering (LEIS. Analysis of phase composition showed that the NiCr thin films were a solid solution of chromium in a nickel matrix with increased nickel lattice parameters. LEIS analysis showed the presence of Ni Cr and O in the first atomic layer. There is a strong suspicion that surface passivation occurred by forming Cr2O3 oxide at the surface.

  4. Compositional analysis of silicon oxide/silicon nitride thin films

    Directory of Open Access Journals (Sweden)

    Meziani Samir

    2016-06-01

    Full Text Available Hydrogen, amorphous silicon nitride (SiNx:H abbreviated SiNx films were grown on multicrystalline silicon (mc-Si substrate by plasma enhanced chemical vapour deposition (PECVD in parallel configuration using NH3/SiH4 gas mixtures. The mc-Si wafers were taken from the same column of Si cast ingot. After the deposition process, the layers were oxidized (thermal oxidation in dry oxygen ambient environment at 950 °C to get oxide/nitride (ON structure. Secondary ion mass spectroscopy (SIMS, Rutherford backscattering spectroscopy (RBS, Auger electron spectroscopy (AES and energy dispersive X-ray analysis (EDX were employed for analyzing quantitatively the chemical composition and stoichiometry in the oxide-nitride stacked films. The effect of annealing temperature on the chemical composition of ON structure has been investigated. Some species, O, N, Si were redistributed in this structure during the thermal oxidation of SiNx. Indeed, oxygen diffused to the nitride layer into Si2O2N during dry oxidation.

  5. Composition change and capacitance properties of ruthenium oxide thin film

    Institute of Scientific and Technical Information of China (English)

    刘泓; 甘卫平; 刘仲武; 郑峰

    2015-01-01

    RuO2·nH2O film was deposited on tantalum foils by electrodeposition and heat treatment using RuCl3·3H2O as precursor. Surface morphology, composition change and cyclic voltammetry from precursor to amorphous and crystalline RuO2·nH2O films were studied by X-ray diffractometer, Fourier transformation infrared spectrometer, differential thermal analyzer, scanning electron microscope and electrochemical analyzer, respectively. The results show that the precursor was transformed gradually from amorphous to crystalline phase with temperature. When heat treated at 300 °C for 2 h, RuO2·nH2O electrode surface gains mass of 2.5 mg/cm2 with specific capacitance of 782 F/g. Besides, it is found that the specific capacitance of the film decreased by roughly 20%with voltage scan rate increasing from 5 to 250 mV/s.

  6. Thermal postbuckling of thin-walled composite stiffeners

    Science.gov (United States)

    Noor, Ahmed K.; Peters, J. M.

    1991-01-01

    A study is made of the thermal postbuckling response of composite stiffeners subjected to prescribed edge displacement and a temperature rise. The flanges and web of the stiffeners are modeled by using two-dimensional plate finite elements. A mixed formulation is used with the fundamental unknowns consisting of the generalized displacements and the stress resultants of the plate. A reduction method is used in conjunction with mixed finite element models for determining the postbuckling response of the stiffeners. Sensitivity derivatives are evaluated and used to study the effects of variations in the different lamination and material parameters of the stiffeners on their postbuckling response characteristics. Numerical studies are presented for anisotropic stiffeners with Zee and channel sections.

  7. Photoluminescence properties of ZnSe/SiO2 composite thin films prepared by sol-gel method

    Institute of Scientific and Technical Information of China (English)

    JIANG Hai-qing; CHE Jun; YAO Xi

    2006-01-01

    ZnSe/SiO2 composite thin films was prepared by sol-gel method. XRD results indicate the phase structure of ZnSe particles embedded in ZnSe/SiO2 composite thin films is sphalerite (cubic ZnS). Spectroscopic ellipsometers were used to investigated the dependences of ellipsometric angle with wavelength of ZnSe/SiO2 composite thin films. The optical constant,thickness,porosity and the concentration of ZnSe of ZnSe/SiO2 thin composite films were fitted according to Maxwell-Garnett effective medium theory. The thickness of ZnSe/SiO2 composite thin thin films was also measured through surface profile. The photoluminescence properties of ZnSe/SiO2 thin composite thin films was investigated through fluorescence spectrometer. The photoluminescence results show that the emission peak at 487 nm (2.5 eV) is excited at 395 nm corresponds to the band-to-band emission of sphalerite ZnSe crystal(2.58 eV). The strength free exciton emission and other emission peaks correlating to ZnSe lattice defect were also observed.

  8. Flexible, thin films of graphene-polymer composites for EMI shielding

    Science.gov (United States)

    Jan, Rahim; Habib, Amir; Aftab Akram, Muhammad; Ahmad, Imtiaz; Shah, Attaullah; Sadiq, Muhammad; Hussain, Akhtar

    2017-03-01

    Liquid-phase-exfoliated, pristine graphene nanosheets (GNSs) are dispersed in thermoplastic polyurethane (TPU) to obtain free-standing conducting composite films. The composites are tested for electromagnetic interference (EMI) shielding applications in the X-band (8-12 GHz). A constant increase in the electromagnetic attenuation is observed as a function of GNS loading (0-0.12 V f). The EMI shielding effectiveness of about 1 dB for the neat polymer is enhanced to about 14 dB at 0.12 V f GNS as the electromagnetic energy is dissipated due to the GNS conducting network formed inside. Conducting behavior of GNS-TPU composites is confirmed by electrical conductivity measurements along with cyclic voltammetry as the band gap is reduced with a graphene increment. Scanning electron microscopy predicts a homogeneous dispersion of GNS inside composites. For such thin composite films (0.03-0.05 mm), the EMI shielding effectiveness is considerable.

  9. Quantifying Local Thickness and Composition in Thin Films of Organic Photovoltaic Blends by Raman Scattering

    KAUST Repository

    Rodríguez-Martínez, Xabier

    2017-07-06

    We report a methodology based on Raman spectroscopy that enables the non-invasive and fast quantitative determination of local thickness and composition in thin films (from few monolayers to hundreds of nm) of one or more components. We apply our methodology to blends of organic conjugated materials relevant in the field of organic photovoltaics. As a first step, we exploit the transfer-matrix formalism to describe the Raman process in thin films including reabsorption and interference effects of the incoming and scattered electric fields. This allows determining the effective solid-state Raman cross-section of each material by studying the dependence of the Raman intensity on film thickness. These effective cross sections are then used to estimate the local thickness and composition in a series of polymer:fullerene blends. We find that the model is accurate within ±10 nm in thickness and ±5 vol% in composition provided that (i) the film thickness is kept below the thickness corresponding to the first maximum of the calculated Raman intensity oscillation; (ii) the materials making up the blend show close enough effective Raman cross-sections; and (iii) the degree of order attained by the conjugated polymer in the blend is similar to that achieved when cast alone. Our methodology opens the possibility to make quantitative maps of composition and thickness over large areas (from microns to centimetres squared) with diffraction-limited resolution and in any multi-component system based thin film technology.

  10. Investigation of the preparation and properties of organic dye/metal oxide composite thin films

    Science.gov (United States)

    Jaeger, Steffen; Neumann, F.; Klages, Claus-Peter

    1994-11-01

    In this study the growth, structure and physical, particularly optical properties of composite thin films (copper-phthalocyanine-SiO2) with different dye contents are investigated by means of optical spectroscopy (UV-IR), electron probe micro analysis, atomic force microscopy and scanning electron microscopy measurements and compared with the properties of pure dye thin films of different thicknesses and dye/metal oxide multilayer structures, respectively. The composite thin films show spectral shifts and changes in the extension and the intensity of the typical absorption bands in the visible spectral range depending on the dye concentration in the composites. This behavior is accompanied by pronounced color changes, e.g. from blue-green to green in the CuPc-SiO2 system. The results show, that the CuPc- SiO2 composite properties are mainly influenced by the size and kind of dye aggregates in the films (monomer, dimer) and not by interaction of dye molecules with the metal oxide matrix.

  11. Free vibrations of thin-walled semicircular graphite-epoxy composite frames

    Science.gov (United States)

    Noor, Ahmed K.; Carden, Huey D.; Peters, Jeanne M.

    1991-01-01

    A detailed study is made of the effects of variations in lamination and material parameters of thin-walled composite frames on their vibrational characteristics. The structures considered are semicircular thin-walled frames with I and J sections. The flanges and webs of the frames are modeled by using two-dimensional shell and plate finite elements. A mixed formulation is used with the fundamental unknowns consisting of both the generalized displacements and stress resultants in the frame. The frequencies and modes predicted by the two-dimensional finite-element model are compared with those obtained from experiments, as well as with the predictions of a one-dimensional, thin-walled-beam, finite-element model. A detailed study is made of the sensitivity of the vibrational response to variations in the fiber orientation, material properties of the individual layers, and boundary conditions.

  12. An asymmetric electrically conducting self-aligned graphene/polymer composite thin film for efficient electromagnetic interference shielding

    Directory of Open Access Journals (Sweden)

    Pradip Kumar

    2017-01-01

    Full Text Available Here, we study the self-aligned asymmetric electrically conductive composite thin film prepared via casting of graphene oxide (GO/poly (vinylidene-hexafluoropropylene (PVDF-HFP dispersion, followed by low temperature hydriodic acid reduction. The results showed that composite thin film revealed the high orientation of graphene sheets along the direction of film surface. However, graphene sheets are asymmetrically distributed along the film thickness direction in the composite film. Both sides of as prepared composite film showed different surface characteristics. The asymmetric surface properties of composite film induced distinction of surface resistivity response; top surface resistivity (21 Ohm is ∼ 4 times higher than bottom surface resistivity (5 Ohm. This asymmetric highly electrically conducting composite film revealed efficient electromagnetic interference (EMI shielding effectiveness of ∼ 30 dB. This study could be crucial for achieving aligned asymmetric composite thin film for high-performance EMI shielding radiation.

  13. Design of step composition gradient thin film transistor channel layers grown by atomic layer deposition

    Science.gov (United States)

    Ahn, Cheol Hyoun; Hee Kim, So; Gu Yun, Myeong; Koun Cho, Hyung

    2014-12-01

    In this study, we proposed the artificially designed channel structure in oxide thin-film transistors (TFTs) called a "step-composition gradient channel." We demonstrated Al step-composition gradient Al-Zn-O (AZO) channel structures consisting of three AZO layers with different Al contents. The effects of stacking sequence in the step-composition gradient channel on performance and electrical stability of bottom-gate TFT devices were investigated with two channels of inverse stacking order (ascending/descending step-composition). The TFT with ascending step-composition channel structure (5 → 10 → 14 at. % Al composition) showed relatively negative threshold voltage (-3.7 V) and good instability characteristics with a reduced threshold voltage shift ( Δ 1.4 V), which was related to the alignment of the conduction band off-set within the channel layer depending on the Al contents. Finally, the reduced Al composition in the initial layer of ascending step-composition channel resulted in the best field effect mobility of 4.5 cm2/V s. We presented a unique active layer of the "step-composition gradient channel" in the oxide TFTs and explained the mechanism of adequate channel design.

  14. Deterministic aperiodic composite lattice-structured silicon thin films for photon management

    CERN Document Server

    Xavier, Jolly; Becker, Christiane

    2016-01-01

    Exotic manipulation of the flow of photons in nanoengineered semiconductor materials with an aperiodic distribution of nanostructures plays a key role in efficiency-enhanced and industrially viable broadband photonic technologies. Through a generic deterministic nanotechnological route, in addition to periodic, transversely quasicrystallographic or disordered random photonic lattices, here we show scalable nanostructured semiconductor thin films on large area nanoimprinted substrates up to 4cm^2 with advanced functional features of aperiodic composite nanophotonic lattices having tailorable supercell tiles. The richer Fourier spectra of the presented artificially nanostructured materials with well-defined lattice point morphologies are designed functionally akin to two-dimensional incommensurate intergrowth aperiodic lattices-comprising periodic photonic crystals and in-plane quasicrystals as subgroups. The composite photonic lattice-structured crystalline silicon thin films with tapered nanoholes or nanocone...

  15. Thin-film composite crosslinked polythiosemicarbazide membranes for organic solvent nanofiltration (OSN)

    KAUST Repository

    Aburabie, Jamaliah

    2015-01-01

    In this work we report a new class of solvent stable thin-film composite (TFC) membrane fabricated on crosslinked polythiosemicarbazide (PTSC) as substrate that exhibits superior stability compared with other solvent stable polymeric membranes reported up to now. Integrally skinned asymmetric PTSC membranes were prepared by the phase inversion process and crosslinked with an aromatic bifunctional crosslinker to improve the solvent stability. TFC membranes were obtained via interfacial polymerization using trimesoyl chloride (TMC) and diaminopiperazine (DAP) monomers. The membranes were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and contact angle measurement.The membranes exhibited high fluxes toward solvents like tetrahydrofuran (THF), dimethylformamide (DMF) and dimethylsulfoxide (DMSO) ranging around 20L/m2 h at 5bar with a molecular weight cut off (MWCO) of around 1000g/mol. The PTSC-based thin-film composite membranes are very stable toward polar aprotic solvents and they have potential applications in the petrochemical and pharmaceutical industry.

  16. Composition-dependent nanostructure of Cu(In,Ga)Se{sub 2} powders and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Schnohr, C.S., E-mail: c.schnohr@uni-jena.de [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Kämmer, H.; Steinbach, T.; Gnauck, M. [Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, 07743 Jena (Germany); Rissom, T.; Kaufmann, C.A.; Stephan, C. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Schorr, S. [Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Institut für Geologische Wissenschaften, Freie Universität Berlin, Malteserstr. 74-100, 12249 Berlin (Germany)

    2015-05-01

    Atomic-scale structural parameters of Cu(In,Ga)Se{sub 2} powders and polycrystalline thin films were determined as a function of the In and Cu contents using X-ray absorption spectroscopy. No difference in the two sample types is observed for the average bond lengths demonstrating the strong tendency towards bond length conservation typical for tetrahedrally coordinated semiconductors. In contrast, the bond length variation is significantly smaller in the thin films than in the powders, particularly for Cu-poor material. This difference in the nanostructure is proposed to originate from differences in the preparation conditions, most prominently from the different history of Cu composition. - Highlights: • Cu(In,Ga)Se{sub 2} powders and thin films are studied with X-ray absorption spectroscopy. • Structural parameters are determined as a function of the In and Cu contents. • The element-specific average bond lengths are identical for powders and thin films. • The Ga-Se/In-Se bond length variation is smaller for thin films than for powders. • The differences are believed to stem from the different history of the Cu content.

  17. Vibration and Stability of Variable Cross Section Thin-Walled Composite Shafts with Transverse Shear

    Directory of Open Access Journals (Sweden)

    Ma Jing-min

    2015-01-01

    Full Text Available A dynamic model of composite shaft with variable cross section is presented. Free vibration equations of the variable cross section thin-walled composite shaft considering the effect of shear deformation are established based on a refined variational asymptotic method and Hamilton’s principle. The numerical results calculated by Galerkin method are analyzed to indicate the effects of ply angle, taper ratio, and transverse shear deformation on the first natural frequency and critical rotating speed. The results are compared with those obtained by using finite element package ANSYS and available in the literature using other models.

  18. Composite Thin-Disk Laser Scaleable to 100 kW Average Power Output and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    Zapata, L.; Beach, R.; Payne, S.

    2000-06-01

    By combining newly developed technologies to engineer composite laser components with state of the art diode laser pump delivery technologies, we are in a position to demonstrate high beam quality, continuous wave, laser radiation at scaleable high average powers. The crucial issues of our composite thin disk laser technology were demonstrated during a successful first light effort. The high continuous wave power levels that are now within reach make this system of high interest to future DoD initiatives in solid-state laser technology for the laser weapon arena.

  19. A convenient electrolytic assembly of graphene-MOF composite thin film and its photoanodic application

    Science.gov (United States)

    Kaur, Rajnish; Kim, Ki-Hyun; Deep, Akash

    2017-02-01

    In the recent past, the metal organic frameworks (MOFs) have been recognized as attractive photosensitizer materials due to their hierarchically ordered structures and attractive light-harvesting characteristics. In this work, we report the application of a graphene-MOF composite as a potential photosensitizer material in dye-sensitized solar cells (DSSCs). A thin film of graphene-MOF hybrid composite was electrochemically assembled on a TiO2/FTO substrate and the different characteristics of the prepared film were investigated. This novel photoanode material hybrid structure demonstrated the potency of an alternative solid-state DSSC configuration. The 2.2% observed power conversion efficiency of the above graphene-MOF composite is a good basis for the further development of graphene-MOF composite-based photoanodes.

  20. Composition of nanocomposites based on thin layers of tin on porous silicon formed by magnetron sputtering

    Science.gov (United States)

    Lenshin, A. S.; Kashkarov, V. M.; Domashevskaya, E. P.; Seredin, P. V.; Ryabtsev, S. V.; Bel'tyukov, A. N.; Gil'mutdinov, F. Z.

    2017-01-01

    Using scanning electron microscopy and X-ray photoelectron spectroscopy the features of morphology and peculiarities of the surface composition of nanocomposites made of thin tin layers by magnetron sputtering formed on porous silicon with pores size of 50-150 nm. Porous silicon was obtained on n-type conductivity crystalline silicon substrate. The obtained nanocomposites were found differ between themselves by the ratio of the main phases: tin dioxide, sub-oxide and metal tin in a dependence on the thickness of the deposited tin layer. Fraction of the oxidized tin in the phase composition of composites was reduced from the surface to the bulk of the sample. Moreover, it was determined that the deposition of tin nanolayers did not result in a considerable change of the phase composition of porous silicon substrate.

  1. Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

    Science.gov (United States)

    Reis, Rackel; Dumée, Ludovic F.; Tardy, Blaise L.; Dagastine, Raymond; Orbell, John D.; Schutz, Jürg A.; Duke, Mikel C.

    2016-07-01

    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties.

  2. Hydrophilic nanofibers as new supports for thin film composite membranes for engineered osmosis.

    Science.gov (United States)

    Bui, Nhu-Ngoc; McCutcheon, Jeffrey R

    2013-02-05

    Engineered osmosis (e.g., forward osmosis, pressure-retarded osmosis, direct osmosis) has emerged as a new platform for applications to water production, sustainable energy, and resource recovery. The lack of an adequately designed membrane has been the major challenge that hinders engineered osmosis (EO) development. In this study, nanotechnology has been integrated with membrane science to build a next generation membrane for engineered osmosis. Specifically, hydrophilic nanofiber, fabricated from different blends of polyacrylonitrile and cellulose acetate via electrospinning, was found to be an effective support for EO thin film composite membranes due to its intrinsically wetted open pore structure with superior interconnectivity. The resulting composite membrane exhibits excellent permselectivity while also showing a reduced resistance to mass transfer that commonly impacts EO processes due to its thin, highly porous nanofiber support layer. Our best membrane exhibited a two to three times enhanced water flux and 90% reduction in salt passage when compared to a standard commercial FO membrane. Furthermore, our membrane exhibited one of the lowest structural parameters reported in the open literature. These results indicate that hydrophilic nanofiber supported thin film composite membranes have the potential to be a next generation membrane for engineered osmosis.

  3. Amine Enrichment of Thin-Film Composite Membranes via Low Pressure Plasma Polymerization for Antimicrobial Adhesion.

    Science.gov (United States)

    Reis, Rackel; Dumée, Ludovic F; He, Li; She, Fenghua; Orbell, John D; Winther-Jensen, Bjorn; Duke, Mikel C

    2015-07-15

    Thin-film composite membranes, primarily based on poly(amide) (PA) semipermeable materials, are nowadays the dominant technology used in pressure driven water desalination systems. Despite offering superior water permeation and salt selectivity, their surface properties, such as their charge and roughness, cannot be extensively tuned due to the intrinsic fabrication process of the membranes by interfacial polymerization. The alteration of these properties would lead to a better control of the materials surface zeta potential, which is critical to finely tune selectivity and enhance the membrane materials stability when exposed to complex industrial waste streams. Low pressure plasma was employed to introduce amine functionalities onto the PA surface of commercially available thin-film composite (TFC) membranes. Morphological changes after plasma polymerization were analyzed by SEM and AFM, and average surface roughness decreased by 29%. Amine enrichment provided isoelectric point changes from pH 3.7 to 5.2 for 5 to 15 min of plasma polymerization time. Synchrotron FTIR mappings of the amine-modified surface indicated the addition of a discrete 60 nm film to the PA layer. Furthermore, metal affinity was confirmed by the enhanced binding of silver to the modified surface, supported by an increased antimicrobial functionality with demonstrable elimination of E. coli growth. Essential salt rejection was shown minimally compromised for faster polymerization processes. Plasma polymerization is therefore a viable route to producing functional amine enriched thin-film composite PA membrane surfaces.

  4. A new strategy to fabricate composite thin films with tunable micro- and nanostructures via self-assembly of block copolymers.

    Science.gov (United States)

    Zhao, Xingjuan; Wang, Qian; Lee, Yong-Ill; Hao, Jingcheng; Liu, Hong-Guo

    2015-12-04

    A new and facile strategy to fabricate composite thin films with tunable morphologies via self-assembly of block copolymer molecules at the air/liquid interface is first reported. The morphologies (parallel nanowires and foams) of these freestanding thin films can be tuned by varying the molecular structure or other experimental conditions.

  5. Fully integrated carbon nanotube composite thin film strain sensors on flexible substrates for structural health monitoring

    Science.gov (United States)

    Burton, A. R.; Lynch, J. P.; Kurata, M.; Law, K. H.

    2017-09-01

    Multifunctional thin film materials have opened many opportunities for novel sensing strategies for structural health monitoring. While past work has established methods of optimizing multifunctional materials to exhibit sensing properties, comparatively less work has focused on their integration into fully functional sensing systems capable of being deployed in the field. This study focuses on the advancement of a scalable fabrication process for the integration of multifunctional thin films into a fully integrated sensing system. This is achieved through the development of an optimized fabrication process that can create a broad range of sensing systems using multifunctional materials. A layer-by-layer deposited multifunctional composite consisting of single walled carbon nanotubes (SWNT) in a polyvinyl alcohol and polysodium-4-styrene sulfonate matrix are incorporated with a lithography process to produce a fully integrated sensing system deposited on a flexible substrate. To illustrate the process, a strain sensing platform consisting of a patterned SWNT-composite thin film as a strain-sensitive element within an amplified Wheatstone bridge sensing circuit is presented. Strain sensing is selected because it presents many of the design and processing challenges that are core to patterning multifunctional thin film materials into sensing systems. Strain sensors fabricated on a flexible polyimide substrate are experimentally tested under cyclic loading using standard four-point bending coupons and a partial-scale steel frame assembly under lateral loading. The study reveals the material process is highly repeatable to produce fully integrated strain sensors with linearity and sensitivity exceeding 0.99 and 5 {{V}}/{ε }, respectively. The thin film strain sensors are robust and are capable of high strain measurements beyond 3000 μ {ε }.

  6. A laser ultrasound transducer using carbon nanofibers–polydimethylsiloxane composite thin film

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Bao-Yu; Kim, Jinwook; Li, Sibo; Jiang, Xiaoning, E-mail: xjiang5@ncsu.edu [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Zhu, Jiadeng; Zhang, Xiangwu [Fiber and Polymer Science Program, Department of Textile Engineering, Chemistry and Science, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2015-01-12

    The photoacoustic effect has been broadly applied to generate high frequency and broadband acoustic waves using lasers. However, the efficient conversion from laser energy to acoustic power is required to generate acoustic waves with high intensity acoustic pressure (>10 MPa). In this study, we demonstrated laser generated high intensity acoustic waves using carbon nanofibers–polydimethylsiloxane (CNFs-PDMS) thin films. The average diameter of the CNFs is 132.7 ± 11.2 nm. The thickness of the CNFs film and the CNFs-PDMS composite film is 24.4 ± 1.43 μm and 57.9 ± 2.80 μm, respectively. The maximum acoustic pressure is 12.15 ± 1.35 MPa using a 4.2 mJ, 532 nm Nd:YAG pulsed laser. The maximum acoustic pressure using the CNFs-PDMS composite was found to be 7.6-fold (17.62 dB) higher than using carbon black PDMS films. Furthermore, the calculated optoacoustic energy conversion efficiency K of the prepared CNFs-PDMS composite thin films is 15.6 × 10{sup −3 }Pa/(W/m{sup 2}), which is significantly higher than carbon black-PDMS thin films and other reported carbon nanomaterials, carbon nanostructures, and metal thin films. The demonstrated laser generated high intensity ultrasound source can be useful in ultrasound imaging and therapy.

  7. OPTICAL BAND GAP AND CONDUCTIVITY MEASUREMENTS OF POLYPYRROLE-CHITOSAN COMPOSITE THIN FILMS

    Institute of Scientific and Technical Information of China (English)

    Mahnaz M.Abdi; H.N.M.Ekramul Mahmud; Luqman Chuah Abdullah; Anuar Kassim; Mohamad Zaki Ab.Rahman; Josephine Liew Ying Chyi

    2012-01-01

    Electrical conductivity and optical properties of polypyrrole-chitosan (PPy-CHI) conducting polymer composites have been investigated to determine the optical transition characteristics and energy band gap of composite films.The two electrode method and Ⅰ-Ⅴ characteristic technique were used to measure the conductivity of the PPy-CHI thin films,and the optical band gap was obtained from their ultraviolet absorption edges.Depending upon experimental parameter,the optical band gap (Eg) was found within 1.30-2.32 eV as estimated from optical absorption data.The band gap of the composite films decreased as the CHI content increased.The room temperature electrical conductivity of PPy-CHI thin films was found in the range of 5.84 × 10-7-15.25 × 10-7 S.cm-1 depending on the chitosan content.The thermogravimetry analysis (TGA)showed that the CHI can improve the thermal stability of PPy-CHI composite films.

  8. Computation of macro-fiber composite integrated thin-walled smart structures

    Science.gov (United States)

    Zhang, S. Q.; Zhang, S. Y.; Chen, M.; Bai, J.; Li, J.

    2016-07-01

    Due to high flexibility, reliability, and strong actuation forces, piezo fiber based composite smart material, macro-fiber composite (MFC), is increasingly applied in various fields for vibration suppression, shape control, and health monitoring. The complexity arrangement of MFC materials makes them difficult in numerical simulations. This paper develops a linear electro-mechanically coupled finite element (FE) model for composite laminated thin-walled smart structures bonded with MFC patches considering arbitrary piezo fiber orientation. Two types of MFCs are considered, namely, MFC-d31 in which the d 31 effect dominates the actuation forces, and MFC-d33 which mainly uses the d 33 effect. The proposed FE model is validated by static analysis of an MFC bonded smart plate.

  9. Atomically thin layers of B-N-C-O with tunable composition.

    Science.gov (United States)

    Ozturk, Birol; de-Luna-Bugallo, Andres; Panaitescu, Eugen; Chiaramonti, Ann N; Liu, Fangze; Vargas, Anthony; Jiang, Xueping; Kharche, Neerav; Yavuzcetin, Ozgur; Alnaji, Majed; Ford, Matthew J; Lok, Jay; Zhao, Yongyi; King, Nicholas; Dhar, Nibir K; Dubey, Madan; Nayak, Saroj K; Sridhar, Srinivas; Kar, Swastik

    2015-07-01

    In recent times, atomically thin alloys of boron, nitrogen, and carbon have generated significant excitement as a composition-tunable two-dimensional (2D) material that demonstrates rich physics as well as application potentials. The possibility of tunably incorporating oxygen, a group VI element, into the honeycomb sp(2)-type 2D-BNC lattice is an intriguing idea from both fundamental and applied perspectives. We present the first report on an atomically thin quaternary alloy of boron, nitrogen, carbon, and oxygen (2D-BNCO). Our experiments suggest, and density functional theory (DFT) calculations corroborate, stable configurations of a honeycomb 2D-BNCO lattice. We observe micrometer-scale 2D-BNCO domains within a graphene-rich 2D-BNC matrix, and are able to control the area coverage and relative composition of these domains by varying the oxygen content in the growth setup. Macroscopic samples comprising 2D-BNCO domains in a graphene-rich 2D-BNC matrix show graphene-like gate-modulated electronic transport with mobility exceeding 500 cm(2) V(-1) s(-1), and Arrhenius-like activated temperature dependence. Spin-polarized DFT calculations for nanoscale 2D-BNCO patches predict magnetic ground states originating from the B atoms closest to the O atoms and sizable (0.6 eV thin platform.

  10. Polarization Induced Changes in LSM Thin Film Electrode Composition Observed by In Operando Raman Spectroscopy and TOF-SIMS

    DEFF Research Database (Denmark)

    McIntyre, Melissa D.; Walker, Robert; Traulsen, Marie Lund

    2015-01-01

    an applied potential.1-3 The presented work explores the polarisation induced changes in LSM electrode composition by utilizing in operando Raman spectroscopy and post mortem ToF-SIMS depth profiling on LSM thin film model electrodes fabricated by pulsed laser deposition on YSZ substrates with a thin (200 nm...... recorded through the LSM thin film electrodes and revealed distinct compositional changes throughout the electrodes (Figure 2). The electrode elements and impurities separated into distinct layers that were more pronounced for the stronger applied polarisations. The mechanism behind this separation...

  11. Interfacial effects in oxide-polymer laminar composite thin film dielectrics for capacitor applications

    Science.gov (United States)

    Tewari, Pratyush

    Continuous increase in the density of active components on microelectronic chip/circuit board requires development of new capacitors with smaller size, weight and cost. Miniaturization in the size of capacitors demands development of high energy density dielectric materials, which are the core of parallel plate capacitors. Nano composite dielectrics comprising high polarizibility oxide fillers randomly dispersed in high breakdown strength polymer matrix are considered as a potential high energy density materials for capacitor applications. Large interfacial volume, generated due to introduction of nano fillers in polymer matrix, might have significant positive contribution towards energy storage in nano composites. However, percolation issues associated with nano fillers and generation of large interfacial volume in nano composites, where complex electric field distribution overlaps with interfacialy modified polymer lead to unclear understanding of polymer-filler interfacial interactions in nano composites. Hence, in the current work laminar composite double layered dielectric structures, which provide relatively simple local field distribution at the interface and ideal series connectivity between oxide and polymer, are used as a model system to understand polymer-oxide interfacial interactions. Interfacial effects are reported for both low permittivity (SiO2-Parylene C) and medium permittivity (ZrO2-P(VDF-TrFE)) laminar composite dielectrics. Pyrolytic vapor decomposition polymerization process was used to grow Parylene C thin films on gold and thermally grown SiO2 surfaces. Enhancement in crystallite dimension with post deposition annealing treatments of Parylene C thin films was found to reduce dielectric loss tangent and hence enhance its dielectric properties. Electric field and temperature dependant leakage current analysis suggested hopping as dominant conduction mechanism in Parylene C thin films. Parylene C thin films in laminar composites showed

  12. Thin metal film-polymer composite for efficient optoacoustic generation (Conference Presentation)

    Science.gov (United States)

    Lee, Taehwa; Guo, L. Jay

    2016-03-01

    Photoacoustic (PA) conversion of metal film absorbers is known to be inefficient because of their low thermal expansion and high light reflectance, as compared to polymeric materials containing light absorbing fillers. Specifically, the PA signal for metal films is typically an order of magnitude lower than those for PDMS-based composites consisting of carbon materials such as carbon blacks, carbon nanotubes, and carbon fibers. However, the carbon-PDMS composites have several disadvantages, e.g., difficulty in controlling film thickness, aggregation of the carbon fillers, and poor patternablility. To overcome these issues and achieve comparable PA amplitudes, a polymer-metal film composite was developed consisting of a thin metal absorber and adjacent transparent polymer layers. The proposed structure shows efficient PA conversion. The measured PA amplitude of the metal film composite is an order of magnitude higher than that of metal-only samples, and comparable to those of the carbon-PDMS composites. The enhanced PA conversion is accomplished by using metal film of a few tens of nanometers, which greatly facilitates heat transfer from the metal film to the surrounding polymers. Moreover, integrating the metal film composite with a photonic cavity can compensate light absorption loss of the thinner metal film. Theoretical and experimental analysis is conducted for understanding the mechanism behind such improvement. This strategy could be implemented for spatial PA signal patterns, especially for deep tissue PA imaging of implants or image-guiding tools. Furthermore, this approach also provides a guideline for designing photoacoustic transmitters and contrast agents.

  13. Composition-structure-function diagrams of Ti-Ni-Au thin film shape memory alloys.

    Science.gov (United States)

    Buenconsejo, Pio John S; Ludwig, Alfred

    2014-12-08

    Ti-Ni-Au thin film materials libraries were prepared from multilayer precursors by combinatorial sputtering. The materials libraries were annealed at 500, 600, and 700 °C for 1 h and then characterized by high-throughput methods to investigate the relations between composition, structure and functional properties. The identified relations were visualized in functional phase diagrams. The goal is to identify composition regions that are suitable as high temperature shape memory alloys. Phase transforming compositions were identified by electrical resistance measured during thermal cycles in the range of -20 and 250 °C. Three phase transformation paths were confirmed: (1) B2-R, (2) B2-R-B19', and (3) B2-B19. For the materials library annealed at 500 °C only the B2-R transformation was observed. For the materials libraries annealed at 600 and 700 °C, all transformation paths were observed. High transformation temperatures (M(s) ≈ 100 °C) were only obtained by annealing at 600 or 700 °C, and with compositions of Ti ≈ 50 at. % and Au > 20 at. %. This is the composition range that undergoes B2-B19 transformation. The phase transformation behaviors were explained according to the compositional and annealing temperature dependence of phase/structure formation, as revealed by X-ray diffraction analysis of the materials libraries.

  14. Effect of Initial Bulk Material Composition on Thermoelectric Properties of Bi2Te3 Thin Films

    Science.gov (United States)

    Budnik, A. V.; Rogacheva, E. I.; Pinegin, V. I.; Sipatov, A. Yu.; Fedorov, A. G.

    2013-07-01

    V2VI3 compounds and solid solutions based on them are known to be the best low-temperature thermoelectric (TE) materials. The predicted possibility of enhancement of the TE figure of merit in two-dimensional (2D) structures has stimulated studies of the properties of these materials in the thin-film state. The goal of the present work is to study the dependences of the Seebeck coefficient S, electrical conductivity σ, Hall coefficient R H, charge carrier mobility μ H, and TE power factor P = S 2 σ of Bi2Te3 thin films on the composition of the initial bulk material used for preparing them. Thin films with thickness d = 200 nm to 250 nm were grown by thermal evaporation in vacuum of stoichiometric Bi2Te3 crystals (60.0 at.% Te) and of crystals with 62.8 at.% Te onto glass substrates at temperatures T S of 320 K to 500 K. It was established that the conductivity type of the initial material is reproduced in films fairly well. For both materials, an increase in T S leads to an increase in the thin-film structural perfection, better correspondence between the film composition and that of the initial material, and increase in S, R H, μ H, σ, and P. The room-temperature maximum values of P for the films grown from crystals with 60.0 at.% and 62.8 at.% Te are P = 7.5 × 10-4 W/K2 m and 35 × 10-4 W/K2 m, respectively. Thus, by using Bi2Te3 crystals with different stoichiometry as initial materials, one can control the conductivity type and TE parameters of the films, applying a simple and low-cost method of thermal evaporation from a single source.

  15. Fabrication and Crystal Structure of Sol-Gel Deposited BST Thin Films with Compositional Gradient

    Directory of Open Access Journals (Sweden)

    Czekaj D.

    2017-06-01

    Full Text Available In the present research technology of compositionally graded barium strontium titanate Ba1-xSrxTiO3 thin films deposited on stainless steel substrates by sol-gel spin coating followed with thermal annealing at T = 650°C is reported. Results of thermal behavior of the sol-gel derived powders with compositions used for fabrication of graded structure (i.e. with Sr mole fraction x = 0.5, 0.4 and 0.3 are described. X-ray diffraction studies of the phase composition and crystal structure of such complex thin film configuration are given. It was found that gel powders exhibited a large total weight loss of about Δm ≈ 44-47%. Three stages of weight loss took place at temperature ranges: below T ≈ 300°C, at ΔT ≈ 300-500°C and between T = 600°C and T = 800°C. Phase analysis has shown that the dominating phase is Ba0.67Sr0.33TiO3 compound while the second phase is Ba0.7Sr0.3TiO3 or Ba0.5Sr0.5TiO3 for “up-graded” and “down-graded” structure, respectively.

  16. Thin Film Nanofibrous Composite Membrane for Dead-End Seawater Desalination

    Directory of Open Access Journals (Sweden)

    Baturalp Yalcinkaya

    2016-01-01

    Full Text Available The aim of the study was to prepare a thin film nanofibrous composite membrane utilized for nanofiltration technologies. The composite membrane consists of a three-layer system including a nonwoven part as the supporting material, a nanofibrous scaffold as the porous surface, and an active layer. The nonwoven part and the nanofibrous scaffold were laminated together to improve the mechanical properties of the complete membrane. Active layer formations were done successfully via interfacial polymerization. A filtration test was carried out using solutions of MgSO4, NaCl, Na2SO4, CaCl2, and real seawater using the dead-end filtration method. The results indicated that the piperazine-based membrane exhibited higher rejection of divalent salt ions (>98% with high flux. In addition, the m-phenylenediamine-based membrane exhibited higher rejection of divalent and monovalent salt ions (>98% divalent and >96% monovalent with reasonable flux. The desalination of real seawater results showed that thin film nanofibrous composite membranes were able to retain 98% of salt ions from highly saline seawater without showing any fouling. The electrospun nanofibrous materials proved to be an alternative functional supporting material instead of the polymeric phase-inverted support layer in liquid filtration.

  17. A new concept in polymeric thin-film composite nanofiltration membranes with antibacterial properties.

    Science.gov (United States)

    Mollahosseini, Arash; Rahimpour, Ahmad

    2013-01-01

    A new, thin film, biofouling resistant, nanofiltration (NF) membrane was fabricated with two key characteristics, viz. a low rate of silver (Ag) release and long-lasting antibacterial properties. In the new approach, nanoparticles were embedded completely in a polymeric thin-film layer. A comparison was made between the new thin-film composite (TFC), NF membrane and thin-film nanocomposite (TFN), and antibacterial NF membranes. Both types of NF membrane were fabricated by interfacial polymerization on a polysulphone sublayer using m-phenylenediamine and trimesoyl chloride as an amine monomer and an acid chloride monomer, respectively. Energy dispersive X-ray (EDX) microanalysis demonstrated the presence of Ag nanoparticles. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to study the cross-sectional and surface morphological properties of the NF membranes. Permeability and salt rejection were tested using a dead-end filtration cell. Ag leaching from the membranes was measured using inductively coupled mass spectrometry (ICP-MS). Morphological studies showed that the TFC NF membranes had better thin-film formation (a more compact structure and a smoother surface) than TFN NF membranes. Performance experiments on TFC NF membranes revealed that permeability was good, without sacrificing salt rejection. The antibacterial properties of the fabricated membranes were tested using the disk diffusion method and viable plate counts. The antibiofouling properties of the membranes were examined by measuring the quantity of bacterial cells released from the biofilm formed (as a function of the amount of biofilm present). A more sensitive surface was observed compared to that of a typical antibacterial NF membrane. The Ag leaching rates were low, which will likely result in long-lasting antibacterial and biofouling resistant properties.

  18. Nondestructive Inspection of Thin Basalt Fiber Reinforced Composites Using Combined Terahertz Imaging and Infrared Thermography

    Directory of Open Access Journals (Sweden)

    Przemyslaw Lopato

    2016-01-01

    Full Text Available The inspection of thin basalt fiber reinforced composite materials was carried out using two nondestructive methods: terahertz time domain imaging and infrared thermography. In order to combine the information about the defects arising in examined materials the inspection results were parametrized. In order to acquire more information content, new approximation based features are proposed. Then, a knowledge extraction based multivariate analysis of preselected features’ vector was carried out. Finally, in order to integrate features distributions of representing different dynamic level of information, a multiresolution wavelet based data fusion algorithm was applied. The results are presented and discussed.

  19. Finite Element Analysis of External Thermal Insulation Composite System: Thin Rendered Expanded Polystyrene Board

    Institute of Scientific and Technical Information of China (English)

    BO Hai-tao; LI Hui-qiang; YIN Xiu-qin

    2009-01-01

    The finite element model of an external thermal composite insulation system, thin rendered expanded polystyrene (EPS) board, was built with ANSYS 1.0, which had two forms: one with window and one without window. The finite element analysis results show that the EPS board had very good insulation capacity at both high or low temperature, stress concentration was produced in the center of wall and around window, and the maximum deformation was observed at the edge of board and the minimum deformation was in the center.

  20. Improvement of thermal management in the composite Yb:YAG/YAG thin-disk laser

    Science.gov (United States)

    Kuznetsov, I. I.; Mukhin, I. B.; Palashov, O. V.

    2016-04-01

    To improve the thermal management in the composite Yb:YAG/YAG thin-disk laser a new design of laser head is developed. Thermal-induced phase distortions, small signal gain and lasing in the upgraded laser head are investigated and compared with previously published results. A substantial decrease of the thermal lens optical power and phase aberrations and increase of the laser slope efficiency are observed. A continuous-wave laser with 440 W average power and 44% slope efficiency is constructed.

  1. Measuring Ultrasonic Acoustic Velocity in a Thin Sheet of Graphite Epoxy Composite

    Science.gov (United States)

    2008-01-01

    A method for measuring the acoustic velocity in a thin sheet of a graphite epoxy composite (GEC) material was investigated. This method uses two identical acoustic-emission (AE) sensors, one to transmit and one to receive. The delay time as a function of distance between sensors determines a bulk velocity. A lightweight fixture (balsa wood in the current implementation) provides a consistent method of positioning the sensors, thus providing multiple measurements of the time delay between sensors at different known distances. A linear fit to separation, x, versus delay time, t, will yield an estimate of the velocity from the slope of the line.

  2. Optical Properties of Semiconductor-Metal Composite Thin Films in the Infrared Region

    Science.gov (United States)

    Nagendra, C. L.; Lamb, James L.

    1993-01-01

    Germanium:Silver (Ge:Ag) composite thin films having different concentrations of Ag, ranging from 7% to 40% have been prepared by dc co-sputtering of Ge an Ag and the films' surface morphology and optical properties have been characterized using transmission electron microscopy (TEM) and infrared spectrophotometry. It is seen that while the films containing lower concentrations of Ag have island-like morphology (i.e. Ag particles distributed in a Ge matrix), the higher metallic concentration films tend to have symmetric distribution of Ag and Ge.

  3. Modeling of damage evaluation in thin composite plate loaded by pressure loading

    Directory of Open Access Journals (Sweden)

    Dudinský M.

    2012-12-01

    Full Text Available This article presents the results of numerical analysis of elastic damage of thin laminated long fiber-reinforced composite plate consisting of unidirectional layers which is loaded by uniformly distributed pressure. The analysis has been performed by means of the finite element method (FEM. The numerical implementation uses layered plate finite elements based on the Kirchhoff plate theory. System of nonlinear equations has been solved by means of the Newton- Raphson procedure. Evolution of damage has been solved using the return-mapping algorithm based on the continuum damage mechanics (CDM. The analysis was performed using own program created in MATLAB. Problem of laminated fiber-reinforced composite plate fixed on edges for two different materials and three different laminate stacking sequences (LSS was simulated. Evolution of stresses vs. strains and also evolution of damage variables in critical points of the structure are shown.

  4. Separation of hydrogen using thin film palladium-ceramic composite membrane

    Energy Technology Data Exchange (ETDEWEB)

    Ilias, S.; King, F.G.; Su, N.; Udo-Aka, U.I.

    1995-11-01

    The primary objective of this study was to prepare and characterize a hydrogen permselective palladium-ceramic composite membrane for high temperature gas separations and catalytic membrane reactors. Electroless plating method was used as a potential route to deposit a thin palladium film on microporous ceramic substrate. The objectives of the work presented here were to characterize the new Pd-ceramic composite membrane by SEM and EDX analysis and to carry out fundamental permeability measurements of the membrane at elevated temperatures and pressures. The potential application of membranes in high temperature gas separation and reactor technology have been recognized by many investigators. In the coal gasification process, the exit gases are normally hydrogen, carbon monoxide, carbon dioxide, hydrogen sulfide, and water vapor. The objective is to obtain hydrogen from this gas mixture.

  5. Compositional influence on the electrical performance of zinc indium tin oxide transparent thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Marsal, A. [Dept Enginyeria Electronica and Center of Research in Nanoengineering, Universitat Politècnica Catalunya, Barcelona (Spain); Carreras, P. [Dept Física Aplicada i Òptica, Universitat de Barcelona, Barcelona (Spain); Puigdollers, J.; Voz, C.; Galindo, S.; Alcubilla, R. [Dept Enginyeria Electronica and Center of Research in Nanoengineering, Universitat Politècnica Catalunya, Barcelona (Spain); Bertomeu, J. [Dept Física Aplicada i Òptica, Universitat de Barcelona, Barcelona (Spain); Antony, A. [Dept Física Aplicada i Òptica, Universitat de Barcelona, Barcelona (Spain); Indian Institute of Technology, Bombay (India)

    2014-03-31

    In this work, zinc indium tin oxide layers with different compositions are used as the active layer of thin film transistors. This multicomponent transparent conductive oxide is gaining great interest due to its reduced content of the scarce indium element. Experimental data indicate that the incorporation of zinc promotes the creation of oxygen vacancies, which results in a higher free carrier density. In thin-film transistors this effect leads to a higher off current and threshold voltage values. The field-effect mobility is also strongly degraded, probably due to coulomb scattering by ionized defects. A post deposition annealing in air reduces the density of oxygen vacancies and improves the field-effect mobility by orders of magnitude. Finally, the electrical characteristics of the fabricated thin-film transistors have been analyzed to estimate the density of states in the gap of the active layers. These measurements reveal a clear peak located at 0.3 eV from the conduction band edge that could be attributed to oxygen vacancies. - Highlights: • Zinc promotes the creation of oxygen vacancies in zinc indium tin oxide transistors. • Post deposition annealing in air reduces the density of oxygen. • Density of states reveals a clear peak located at 0.3 eV from the conduction band.

  6. Synthesis and surface properties of polyamide-CuxSe composite thin films

    Science.gov (United States)

    Ivanauskas, Remigijus; Baltrusaitis, Jonas

    2013-10-01

    A study of copper selenide (CuxSe) thin film deposition on PA 6 polymer surface via adsorption/diffusion method and the resulting surface properties is presented. A two stage process used to deposit these thin films involves (a) selenization in 0.1 M K2SeS2O6 at pH 2.15 and 60 °C followed by (b) treatment with 0.34 M Cu(II) and 0.06 M Cu(I) salt solution at 80 °C. Resulting chemical and physical properties of CuxSe films were investigated using XRD, XPS, SEM and sheet resistivity measurements. XRD data showed a complex mixture of CuxSe phases with peaks due to the elemental Se present at longer exposures. Thin film bulk elemental composition varied with the exposure time whereas XPS analysis showed surface to be slightly copper enriched. Additionally, mostly Cusbnd Se bonds were observed on the surface with minor oxidation products. SEM crossectional analysis showed distinct CuxSe film formation on PA 6 surface with thickness of ∼1-5 μm. Finally, it was found that sheet resistance of 150 ± 10 Ω/□ was achieved after 120 min of selenization for all samples and remained constant after longer exposures.

  7. Preparation, characterization and electrochromic properties of composite thin films incorporation of polyaniline

    Science.gov (United States)

    Farasat, Mahshid; Golzan, M. Maqsood; Farhadi, Khalil; Shojaei, S. H. Reza; Gheisvandi, Sorayya

    2016-05-01

    Two different electrochromic composite films consisting of aniline/sodium molybdate (S1) and aniline/ferric nitrate (S2) were obtained by electrochemical polymerization method on indium tin oxide (ITO) coated glass substrates in oxalic acid (H2C2O4ṡ2H2O) aqueous solution. The electrochromic properties of the resulting thin films were investigated by spectroelectrochemical measurement and cyclic voltammetry (CV). Under a square electrical potential, they show capacitive current characteristic and represent electrochromic performance, with maximum optical attenuations (ΔT%) of 30.8% at 355nm and 28.3% at 400nm for aniline/ferric nitrate and aniline/sodium molybdate thin films, respectively. Optical behavior of thin films was examined by UV-Vis spectrophotometry technique. The doped films indicated multiple color changes (yellow; green; and bluish green). The spectra also showed that produced layers have high absorption of UV radiation with respect to pure polyaniline (PANI) films. The optical band gap energy of PANI film decreased by dopant injection. Due to their decent transparency and electrochromic behavior, they are promising materials for electrochromic devices.

  8. Influence of Bath Composition on Magnetic Properties of Electrodeposited Co-Pt-W Thin Films

    Institute of Scientific and Technical Information of China (English)

    GE Hong-liang; WEI Guo-ying; WU Qiong; ZHOU Qiao-ying; WANG Xin-yan

    2007-01-01

    Effect of bath composition ([Co2+]/[PtⅣ] and [WO2-4], [cit-]) and pH on the magnetic properties of electrodeposited Co-Pt-W thin films has been investigated. Electrodeposited Co-Pt-W thin films exhibited strong perpendicular magnetic anisotropy when the ratio of [Co2+] to [PtⅣ] was 10; cathode current efficiency and perpendicular magnetic anisotropy showed little variations when [WO2-4] was lower than 0.1 mol/L, but perpendicular magnetic anisotropy had strengthened when [WO2-4] was over 0.1 mol/L, which could be explained by the fact that the hydrogen evolution could produce pores as magnetic domain pinnings; citrate as complexing reagent can promote the polarization of [Co2+] and [PtⅣ]. As a result, the equilibrium electrode potentials of cobalt and platinum moved to negative direction, which led to the co-deposition of Co, Pt, and W. It was also found out that the as-deposited Co-Pt-W hard magnetic thin films were very homogeneous, smooth, and had the maximum coercivity for the bath pH 8.5 and the concentration of citrate 0.26 mol/L.

  9. Tailoring the Composition and Properties of Sprayed CuSbS2 Thin Films by Using Polymeric Additives

    Directory of Open Access Journals (Sweden)

    Ionut Popovici

    2012-01-01

    Full Text Available CuSbS2 thin films were obtained by spray pyrolysis deposition, using polymeric additives for controlling the surface properties and film’s composition. Ternary crystalline chalcostibite compounds have been obtained without any postdeposition treatments. XRD spectra and IR spectroscopy were used to characterize films composition and interactions between components. Films morphology and surface energy were investigated using AFM microscopy and contact angle measurements. Hydrophobic and hydrophilic polymers strongly influence the composition and film morphology.

  10. Thin and flexible solid-state organic ionic plastic crystal-polymer nanofibre composite electrolytes for device applications.

    Science.gov (United States)

    Howlett, Patrick C; Ponzio, Florian; Fang, Jian; Lin, Tong; Jin, Liyu; Iranipour, Nahid; Efthimiadis, Jim

    2013-09-07

    All solid-state organic ionic plastic crystal-polymer nanofibre composite electrolytes are described for the first time. The new composite materials exhibit enhanced conductivity, excellent thermal, mechanical and electrochemical stability and allow the production of optically transparent, free-standing, flexible, thin film electrolytes (10's μms thick) for application in electrochemical devices. Stable cycling of a lithium cell incorporating the new composite electrolyte is demonstrated, including cycling at lower temperatures than previously possible with the pure material.

  11. Dynamic stiffness matrix of thin-walled composite I-beam with symmetric and arbitrary laminations

    Science.gov (United States)

    Kim, Nam-Il; Shin, Dong Ku; Park, Young-Suk

    2008-11-01

    For the spatially coupled free vibration analysis of thin-walled composite I-beam with symmetric and arbitrary laminations, the exact dynamic stiffness matrix based on the solution of the simultaneous ordinary differential equations is presented. For this, a general theory for the vibration analysis of composite beam with arbitrary lamination including the restrained warping torsion is developed by introducing Vlasov's assumption. Next, the equations of motion and force-displacement relationships are derived from the energy principle and the first order of transformed simultaneous differential equations are constructed by using the displacement state vector consisting of 14 displacement parameters. Then explicit expressions for displacement parameters are derived and the exact dynamic stiffness matrix is determined using force-displacement relationships. In addition, the finite-element (FE) procedure based on Hermitian interpolation polynomials is developed. To verify the validity and the accuracy of this study, the numerical solutions are presented and compared with analytical solutions, the results from available references and the FE analysis using the thin-walled Hermitian beam elements. Particular emphasis is given in showing the phenomenon of vibrational mode change, the effects of increase of the modulus and the bending-twisting coupling stiffness for beams with various boundary conditions.

  12. Ceramic thin film thermocouples for SiC-based ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Wrbanek, John D., E-mail: John.D.Wrbanek@nasa.gov; Fralick, Gustave C.; Zhu Dongming

    2012-06-30

    Conductive ceramic thin film thermocouples were investigated for application to silicon carbide fiber reinforced silicon carbide ceramic matrix composite (SiC/SiC CMC) components. High temperature conductive oxides based on indium and zinc oxides were selected for testing to high temperatures in air. Sample oxide films were first sputtered-deposited on alumina substrates then on SiC/SiC CMC sample disks. Operational issues such as cold junction compensation to a 0 Degree-Sign C reference, resistivity and thermopower variations are discussed. Results show that zinc oxides have an extremely high resistance and thus increased complexity for use as a thermocouple, but thermocouples using indium oxides can achieve a strong, nearly linear response to high temperatures. - Highlights: Black-Right-Pointing-Pointer Oxide thin film thermocouples tested for SiC/SiC ceramic matrix composites (CMCs) Black-Right-Pointing-Pointer In{sub 2}O{sub 3}, N:In{sub 2}O{sub 3}, ZnO, AlZnO sputtered and tested on Al{sub 2}O{sub 3} and CMC substrates Black-Right-Pointing-Pointer ZnO, AlZnO have high resistance, complex temperature response. Black-Right-Pointing-Pointer In{sub 2}O{sub 3}, N:In{sub 2}O{sub 3} conductive at room temperature, more linear temperature response.

  13. Broadband epsilon-near-zero metamaterials based on metal-polymer composite thin films

    Science.gov (United States)

    Pinchuk, Pavlo; Jiang, Ke

    2015-10-01

    Epsilon-near-zero (ENZ) metamaterials are designed to exhibit a near-zero response for the real part of the dielectric permittivity at a given frequency or in a specific frequency range. Typically, this frequency range is relatively small. In this paper, we present an approach to broaden this range by controlling the size of the nanoparticles embedded in a thin film. Noble metal nanoparticles exhibit an external size effect that redshifts the Surface Plasmon Resonance frequency with an increase of the size of the particles. The absorption spectrum of a material can be directly related to its dielectric permittivity via the Kramers-Kronig relations. We use the Kramers-Kronig relations to retrieve the complex effective dielectric permittivity of a composite film, which is designed to exhibit ENZ behavior over a broad frequency range. We synthesize a composite thin film embedded with metal nanoparticles of a broad size distribution. Such a material exhibits a broad SPR, and, in turn, broadband ENZ behavior.

  14. Compositional analysis of polycrystalline hafnium oxide thin films by heavy-ion elastic recoil detection analysis

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, F.L. [Departamento de Electronica y Tecnologia de Computadoras, Universidad Politecnica de Cartagena, Campus Universitario Muralla del Mar, E-30202 Cartagena (Spain)]. E-mail: Felix.Martinez@upct.es; Toledano, M. [Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, E-28025 Madrid (Spain); San Andres, E. [Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, E-28025 Madrid (Spain); Martil, I. [Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, E-28025 Madrid (Spain); Gonzalez-Diaz, G. [Departamento de Fisica Aplicada III, Universidad Complutense de Madrid, E-28025 Madrid (Spain); Bohne, W. [Hahn-Meitner-Institut Berlin, Abteilung SF-4, D-14109 Berlin (Germany); Roehrich, J. [Hahn-Meitner-Institut Berlin, Abteilung SF-4, D-14109 Berlin (Germany); Strub, E. [Hahn-Meitner-Institut Berlin, Abteilung SF-4, D-14109 Berlin (Germany)

    2006-10-25

    The composition of polycrystalline hafnium oxide thin films has been measured by heavy-ion elastic recoil detection analysis (HI-ERDA). The films were deposited by high-pressure reactive sputtering (HPRS) on silicon wafers using an oxygen plasma at pressures between 0.8 and 1.6 mbar and during deposition times between 0.5 and 3.0 h. Hydrogen was found to be the main impurity and its concentration increased with deposition pressure. The composition was always slightly oxygen-rich, which is attributed to the oxygen plasma. Additionally, an interfacial silicon oxide thin layer was detected and taken into account. The thickness of the hafnium oxide film was found to increase linearly with deposition time and to decrease exponentially with deposition pressure, whereas the thickness of the silicon oxide interfacial layer has a minimum as a function of pressure at around 1.2 mbar and increases slightly as a function of time. The measurements confirmed that this interfacial layer is formed mainly during the early stages of the deposition process.

  15. Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System

    Directory of Open Access Journals (Sweden)

    Somen K. Bhudolia

    2017-03-01

    Full Text Available For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA thermoplastic matrix, Elium®. Vacuum assisted resin infusion (VARI process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS and NCF with novel reactive thermoplastic (TP resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented.

  16. Tensile strength of thin resin composite layers as a function of layer thickness.

    Science.gov (United States)

    Alster, D; Feilzer, A J; De Gee, A J; Davidson, C L

    1995-11-01

    As a rule, cast restorations do not allow for free curing contraction of the resin composite luting cement. In a rigid situation, the resulting contraction stress is inversely proportional to the resin layer thickness. Adhesive technology has demonstrated, however, that thin joints may be considerably stronger than thicker ones. To investigate the effects of layer thickness and contraction stress on the tensile strength of resin composite joints, we cured cylindrical samples of a chemically initiated resin composite (Clearfil F2) in restrained conditions and subsequently loaded them in tension. The samples had a diameter of 5.35 mm and thicknesses of 50, 100, 200, 300, 400, 500, 600, and 700 microns, 1.4 mm, or 2.7 mm. None of the samples fractured due to contraction stress prior to tensile loading. Tensile strength decreased gradually from 62 +/- 2 MPa for the 50-microns layer to 31 +/- 4 MPa for the 2.7-mm layer. The failures were exclusively cohesive in resin for layers between 50 and 400 microns thick. Between 500 and 700 microns, the failures were cohesive or mixed adhesive/cohesive, while the 1.4- and 2.7-mm layers always failed in a mixed adhesive/cohesive mode. For the resin composite tested, the contraction stress did not endanger the cohesive strength. It was concluded that if adhesion to tooth structure were improved, thinner adhesive joints might enhance the clinical success of luted restorations.

  17. Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System

    Science.gov (United States)

    Bhudolia, Somen K.; Perrotey, Pavel; Joshi, Sunil C.

    2017-01-01

    For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs) composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA) thermoplastic matrix, Elium®. Vacuum assisted resin infusion (VARI) process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS) and NCF with novel reactive thermoplastic (TP) resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented. PMID:28772654

  18. Annealing effect on the electrical properties and composition of a NiCrAl thin film resistor

    Science.gov (United States)

    Chuang, Nai-Chuan; Lin, Jyi-Tsong; Chen, Huey-Ru

    2015-12-01

    The composition of NiCrAl thin film resistors, under different annealing conditions in a N2 atmosphere, was investigated. The Auger electron spectrum (AES) has been used in studying the composition of NiCrAl thin films. The concentration ratio of Cr to Ni decreases when the annealing temperature increases. The electrical properties of a NiCrAl thin film resistor are affected by the concentrations of Cr and Ni, which lead to a higher temperature coefficient of resistance (TCR) and a lower sheet resistivity. The TCR of a NiCrAl thin film resistor is -5 ppm/°C at a 250 °C annealing temperature.

  19. Study of composite thin films for applications in high density data storage

    Science.gov (United States)

    Yuan, Hua

    Granular Co-alloy + oxide thin films are currently used as the magnetic recording layer of perpendicular media in hard disk drives. The microstructure of these films is composed mainly of fine (7--10 nm) magnetic grains physically surrounded by oxide phases, which produce magnetic isolation of the grains. As a result, the magnetic switching volume is maintained as small as the physical grain size. Consequently, ample number of magnetic switching units can be obtained in one recording bit, in other words, higher signal to noise ratios (SNR) can be achieved. Therefore, a good understanding and control of the microstructure of the films is very important for high areal density magnetic recording media. Interlayers and seedlayers play important roles in controlling the microstructure in terms of grain size, grain size distribution, oxide segregation and orientation dispersion of the crystallographic texture. Developing novel interlayers or seedlayers with smaller grain size is a key approach to produce smaller grain size in the recording layer. This study focuses on how to achieve smaller grain sizes in the recording layer through novel interlayer/seedlayer materials and processes. It also discusses the resulting microstructure in smaller-grain-size thin films. Metal + oxide (e.g. Ru + SiO2) composite thin films were chosen as interlayer and seedlayer materials due to their unique segregated microstructure. Such layers can be grown epitaxially on top of fcc metal seedlayers with good orientation. It can also provide an epitaxial growth template for the subsequent magnetic layer (recording layer). The metal and oxide phases in the composite thin films are immiscible. The final microstructure of the interlayer depends on factors, such as, sputtering pressure, oxide species, oxide volume fraction, thickness, alloy composition, temperature etc. Moreover, it has been found that the microstructure of the composite thin films is affected mostly by two important factors

  20. Magnetron sputter deposited tantalum and tantalum nitride thin films: An analysis of phase, hardness and composition

    Energy Technology Data Exchange (ETDEWEB)

    Bernoulli, D. [Laboratory for Nanometallurgy, Department of Materials, ETH-Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich (Switzerland); Müller, U. [EMPA, Swiss Federal Laboratories for Material Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf (Switzerland); Schwarzenberger, M. [Laboratory for Nanometallurgy, Department of Materials, ETH-Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich (Switzerland); Hauert, R. [EMPA, Swiss Federal Laboratories for Material Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf (Switzerland); Spolenak, R. [Laboratory for Nanometallurgy, Department of Materials, ETH-Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich (Switzerland)

    2013-12-02

    Tantalum (Ta) and tantalum nitride thin films are highly important as diffusion barriers and adhesion layers in microelectronics and hard coatings for cutting tools. In this study, the effect of the underlying substrate on the phase formation of Ta and the influence of a changing N{sub 2}/Ar flow ratio on hardness, phase and composition of reactively formed tantalum nitride have been investigated. Ta is DC sputter deposited and forms β-Ta on amorphous diamond-like carbon and on the amorphous natural oxide layers of Ti and Si(100) while a 15 nm TaN seed layer results in the formation of α-Ta. The chemical composition of the topmost layers of a substrate influences the formation of α- and β-Ta. With increasing N{sub 2}/Ar flow ratios a transition from amorphous Ta-rich tantalum nitride over face-centered cubic tantalum nitride (fcc-TaN) to (100) textured fcc-TaN at flow ratios above 45% is observed. The hardness of the tantalum nitride thin film reaches a maximum at a flow ratio of 45%, followed by a decrease in hardness for higher N{sub 2}/Ar flow ratios. The increase in hardness is associated with a decrease in grain size and shows a stronger correlation for a Meyers and Ashworth relationship than for a Hall–Petch relationship. - Highlights: • Chemical composition of the substrate influences the phase of deposited Ta. • FCC-TaN seed layer leads to α-Ta on the natural oxide layers of Ti and Si(100). • Meyers and Ashworth relationship correlates stronger than Hall–Petch relationship.

  1. Cu-In-O composite thin films deposited by reactive DC magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ye Fan [School of Physical Science and Technology and Shenzhen Key Laboratory of Sensor Technologies, Shenzhen University, Shenzhen 518060 (China); Cai Xingmin, E-mail: caixm@szu.edu.c [School of Physical Science and Technology and Shenzhen Key Laboratory of Sensor Technologies, Shenzhen University, Shenzhen 518060 (China); Dai Fuping [Department of Applied Physics, Northwestern Polytechnic University, Xian 710072 (China); Jing Shouyong [Institute of Optoelectronics, Shenzhen University, Shenzhen 518060 (China); Zhang Dongping; Fan Ping; Liu Lijun [School of Physical Science and Technology and Shenzhen Key Laboratory of Sensor Technologies, Shenzhen University, Shenzhen 518060 (China)

    2011-02-01

    Cu-In-O composite thin films were deposited by reactive DC magnetron sputtering at room temperature. The samples were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), UV/vis spectrophotometer, four-probe measurement and Seebeck effect measurement, etc. The samples contain Cu, In and O. The ratios of Cu to In and O to In increase with increase in O{sub 2} flow rates. The ratio of Cu to In is over 1 and this suggests that Cu is in excess. The obtained Cu-In-O thin films are very possibly made of rhombohedral In{sub 2}O{sub 3} and monoclinic CuO. Transmittance of the films decreases with increase in O{sub 2} flow rate. The decrease in transmittance results from increase in Cu content in the films. The optical band gap of all the samples is estimated to be 4.1-4.4 eV, which is larger than those of In{sub 2}O{sub 3} and CuO. The sheet resistance of the films decreases with increase in O{sub 2} flow rate. Conductivity of the films is a little low, due to the addition of Cu and the poor crystalline quality of the film. The conduction behavior of the films is similar to that of In{sub 2}O{sub 3} and the conduction mechanism of Cu-In-O thin films is through O vacancy. -- Research Highlights: {yields}Cu-In-O composite thin films were fabricated by DC sputtering at room temperature. {yields}The films are made of rhombohedral In{sub 2}O{sub 3} and monoclinic CuO. {yields}The transmittance depends on the Cu content in the film. {yields}The direct optical band gap is around 4.1-4.4eV. {yields}The conducting mechanism is due to oxygen vacancy.

  2. Bench Scale Thin Film Composite Hollow Fiber Membranes for Post-Combustion Carbon Dioxide Capture

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, Paul [General Electric Global Research, Niskayuna, NY (United States); Bhandari, Dhaval [General Electric Global Research, Niskayuna, NY (United States); Narang, Kristi [General Electric Global Research, Niskayuna, NY (United States); McCloskey, Pat [General Electric Global Research, Niskayuna, NY (United States); Singh, Surinder [General Electric Global Research, Niskayuna, NY (United States); Ananthasayanam, Balajee [General Electric Global Research, Niskayuna, NY (United States); Howson, Paul [General Electric Global Research, Niskayuna, NY (United States); Lee, Julia [General Electric Global Research, Niskayuna, NY (United States); Wroczynski, Ron [General Electric Global Research, Niskayuna, NY (United States); Stewart, Frederick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Orme, Christopher [Idaho National Lab. (INL), Idaho Falls, ID (United States); Klaehn, John [Idaho National Lab. (INL), Idaho Falls, ID (United States); McNally, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rownaghi, Ali [Georgia Inst. of Technology, Atlanta, GA (United States); Lu, Liu [Georgia Inst. of Technology, Atlanta, GA (United States); Koros, William [Georgia Inst. of Technology, Atlanta, GA (United States); Goizueta, Roberto [Georgia Inst. of Technology, Atlanta, GA (United States); Sethi, Vijay [Western Research Inst., Laramie, WY (United States)

    2015-04-01

    GE Global Research, Idaho National Laboratory (INL), Georgia Institute of Technology (Georgia Tech), and Western Research Institute (WRI) proposed to develop high performance thin film polymer composite hollow fiber membranes and advanced processes for economical post-combustion carbon dioxide (CO2) capture from pulverized coal flue gas at temperatures typical of existing flue gas cleanup processes. The project sought to develop and then optimize new gas separations membrane systems at the bench scale, including tuning the properties of a novel polyphosphazene polymer in a coating solution and fabricating highly engineered porous hollow fiber supports. The project also sought to define the processes needed to coat the fiber support to manufacture composite hollow fiber membranes with high performance, ultra-thin separation layers. Physical, chemical, and mechanical stability of the materials (individual and composite) towards coal flue gas components was considered via exposure and performance tests. Preliminary design, technoeconomic, and economic feasibility analyses were conducted to evaluate the overall performance and impact of the process on the cost of electricity (COE) for a coal-fired plant including capture technologies. At the onset of the project, Membranes based on coupling a novel selective material polyphosphazene with an engineered hollow fiber support was found to have the potential to capture greater than 90% of the CO2 in flue gas with less than 35% increase in COE, which would achieve the DOE-targeted performance criteria. While lab-scale results for the polyphosphazene materials were very promising, and the material was incorporated into hollow-fiber modules, difficulties were encountered relating to the performance of these membrane systems over time. Performance, as measured by both flux of and selectivity for CO2 over other flue gas constituents was found to deteriorate over time, suggesting a system that was

  3. Synthesis of Au microwires by selective oxidation of Au–W thin-film composition spreads

    Directory of Open Access Journals (Sweden)

    Sven Hamann, Hayo Brunken, Steffen Salomon, Robert Meyer, Alan Savan and Alfred Ludwig

    2013-01-01

    Full Text Available We report on the stress-induced growth of Au microwires out of a surrounding Au–W matrix by selective oxidation, in view of a possible application as 'micro-Velcro'. The Au wires are extruded due to the high compressive stress in the tungsten oxide formed by oxidation of elemental W. The samples were fabricated as a thin-film materials library using combinatorial sputter deposition followed by thermal oxidation. Sizes and shapes of the Au microwires were investigated as a function of the W to Au ratio. The coherence length and stress state of the Au microwires were related to their shape and plastic deformation. Depending on the composition of the Au–W precursor, the oxidized samples showed regions with differently shaped Au microwires. The Au48W52 composition yielded wires with the maximum length to diameter ratio due to the high compressive stress in the tungsten oxide matrix. The values of wire length (35 μm and diameter (2 μm achieved at the Au48W52 composition are suitable for micro-Velcro applications.

  4. Outer-selective thin film composite (TFC) hollow fiber membranes for osmotic power generation

    KAUST Repository

    Le, Ngoc Lieu

    2016-01-14

    The pressure-retarded osmosis (PRO) process is a green technique for power generation to respond the world\\'s need of energy sustainability. In this study, we have developed the vital component of the process, i.e. membrane, in the configuration of the outer-selective thin-film composite (TFC) hollow fiber, which is more practical than other configurations in the real applications. The support layer morphology and the formation of the selective polyamide layer have been optimized for a good PRO performance. The results show that the bore fluid with higher amount of the solvent N-methyl-2-pyrrolidone leads to full finger-like hollow fibers, which provide higher flux but lower pressure tolerance. The addition of higher amount of diethylene glycol into the dope solution, improves the pore formation and suppresses the macrovoid formation, while properly lowering the take-up speed increases their wall thickness and pressure tolerance. A simple alcohol-pre-wetting approach on the fiber support leads to a smooth and thin polyamide layer, which is favorable for a high water flux and power density. Its efficiency follows this order: n-propanol>ethanol>methanol>water. The n-propanol pre-wetted TFC membrane can tolerate 17 bar with a peak power density of 9.59 W/m2 at room temperature, using 1 M NaCl solution as the draw solution and DI water as feed. This work demonstrates the potential of outer-selective TFC hollow fiber membranes for energy conversion via PRO process, provides useful database to fabricate suitable support morphology and raise a simple technique to practically form a thin and smooth polyamide layer.

  5. Composition and misfit strain dependence of electrocaloric effect of Pb1-xSrxTiO3 thin films

    Institute of Scientific and Technical Information of China (English)

    Qiu Jian-Hua; Ding Jian-Ning; Yuan Ning-Yi; Wang Xiu-Qin

    2013-01-01

    A Landau-Devonshire thermodynamic theory is employed to investigate the effects of composition and misfit strain on the room-temperature electrocaloric effect of epitaxial Pb1-xSrxTiO3 thin films.The “temperature-misfit strain” phase diagrams with the Sr composition x of 0.1,0.3,and 0.5 are constructed.The introduction of Sr composition reduces the Curie temperature greatly,and enhances the electrocaloric effect.Moreover,the electrocaloric effect largely depends on the misfit strain.Therefore,the Sr composition and the misfit strain can be controlled to obtain the giant room-temperature electrocaloric effect.

  6. Prediction of transmittance spectra for transparent composite electrodes with ultra-thin metal layers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhao; Alford, T. L., E-mail: TA@asu.edu [School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287 (United States); Khorasani, Arash Elhami [ON Semiconductor Corp., Phoenix, Arizona 85005 (United States); Theodore, N. D. [CHD-Fab, Freescale Semiconductor Inc., Tempe, Arizona 85224 (United States); Dhar, A. [Intel Corp., 2501 NW 229th Ave, Hillsboro, Oregon 97124 (United States)

    2015-11-28

    Recent interest in indium-free transparent composite-electrodes (TCEs) has motivated theoretical and experimental efforts to better understand and enhance their electrical and optical properties. Various tools have been developed to calculate the optical transmittance of multilayer thin-film structures based on the transfer-matrix method. However, the factors that affect the accuracy of these calculations have not been investigated very much. In this study, two sets of TCEs, TiO{sub 2}/Au/TiO{sub 2} and TiO{sub 2}/Ag/TiO{sub 2}, were fabricated to study the factors that affect the accuracy of transmittance predictions. We found that the predicted transmittance can deviate significantly from measured transmittance for TCEs that have ultra-thin plasmonic metal layers. The ultrathin metal layer in the TCE is typically discontinuous. When light interacts with the metallic islands in this discontinuous layer, localized surface plasmons are generated. This causes extra light absorption, which then leads to the actual transmittance being lower than the predicted transmittance.

  7. Relating performance of thin-film composite forward osmosis membranes to support layer formation and structure

    KAUST Repository

    Tiraferri, Alberto

    2011-02-01

    Osmotically driven membrane processes have the potential to treat impaired water sources, desalinate sea/brackish waters, and sustainably produce energy. The development of a membrane tailored for these processes is essential to advance the technology to the point that it is commercially viable. Here, a systematic investigation of the influence of thin-film composite membrane support layer structure on forward osmosis performance is conducted. The membranes consist of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation. By systematically varying the conditions used during the casting of the polysulfone layer, an array of support layers with differing structures was produced. The role that solvent quality, dope polymer concentration, fabric layer wetting, and casting blade gate height play in the support layer structure formation was investigated. Using a 1M NaCl draw solution and a deionized water feed, water fluxes ranging from 4 to 25Lm-2h-1 with consistently high salt rejection (>95.5%) were produced. The relationship between membrane structure and performance was analyzed. This study confirms the hypothesis that the optimal forward osmosis membrane consists of a mixed-structure support layer, where a thin sponge-like layer sits on top of highly porous macrovoids. Both the active layer transport properties and the support layer structural characteristics need to be optimized in order to fabricate a high performance forward osmosis membrane. © 2010 Elsevier B.V.

  8. Preparation and optical properties of composite thin films with embedded InP nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    InP nanoparticles embedded in SiO2 thin films were prepared by radio-frequency magnetron co-sputtering. We analyzed the structure and growth behavior of the composite films under different preparation conditions. X-ray diffraction and Raman spectroscopy analyses indicate that InP nanoparticles have a polycrystalline structure. The aver-age size of InP nanoparticles is in the range of 3-10 nm. The broadening and red shift of the Raman peaks were observed,which can be interpreted by the phonon confinement model. Optical transmission spectra indicate that the optical absorp-tion edges of the films can be modulated in the visible light range. The marked blue shift of the absorption edge with respect to that of bulk InP is explained by the quantum con-finement effect. The theoretical values of the blue shift pre-dicted by the effective mass approximation model are differ-ent from the experimental results for the InP-SiO2 system. Analyses indicate that the exciton effective mass of the InP nanoparticles is not constant and is inverse relative to the particles radius,which may be the main reason that results in the discrepancy between the theoretical and the experi-mental result. We discussed the possible transition of the direct band gap to the indirect band gap for InP nanoparti-cles embedded in SiO2 thin films.

  9. Changes to oak woodland stand structure and ground flora composition caused by thinning and burning

    Science.gov (United States)

    Kinkead, Carter O.; Kabrick, John M.; Stambaugh, Michael C.; Grabner, Keith W.

    2013-01-01

    Our objective was to quantify the cumulative effects of prescribed burning and thinning on forest stocking and species composition at a woodland restoration experiment site in the Ozark Highlands of Missouri. Our study used four treatments (burn, harvest, harvest and burn, control) on three slope position and aspect combinations (south, north, ridge) replicated in three complete blocks. Harvested stands were thinned from below to 40 percent residual stocking. Two prescribed fires were applied to both burn and harvest-burn treatment units in a 5-year period. Results reflect changes that have taken place over a 6-year period, from pretreatment conditions to 1 year after the last fire. In this period, there was a 10-percent reduction in the stocking in burned stands compared to control and a 6-percent reduction in harvested and burned stands compared to harvested stands. Compared to the control, percentage ground cover of woodland indicators was seven times greater in burned stands, six times greater in harvested stands, and 22 percent greater in harvested and burned stands. Th ere was no significant (P > 0.05) interaction between aspect and treatment on stocking or ground flora cover. Th is study indicated that silvicultural treatments do achieve various goals that are common to managers who aim to restore woodland communities.

  10. Heat Flux Estimation of a Flame Thermal Spray Process Using a Thermally Thin Composite Calorimeter

    Science.gov (United States)

    Yi, Duo; Serio, Bruno; Lecler, Sylvain; Pfeiffer, Pierre; Costil, Sophie

    2016-12-01

    Temperature measurements take on prime importance in the field of the thermal spray coating since the temperature variation greatly affects the formation of splat morphology and also the coating properties and qualities. The evaluation of the heat flux is therefore essential since temperature variation comes from the energy transfer and conduction of the thermal system. The aim of this study is to estimate the heat flux of a flame thermal spray by solving an inverse heat conduction problem. Firstly, the substrate material and geometry are well designed so that the Biot number is small enough to conform to the lumped capacitance conditions. A lumped capacitance model of a substrate with its coating subjected to a uniform echelon heat flux is evaluated by solving a heat balance equation in the Laplace domain. Then, a thermally thin calorimeter is designed and the experimental thermogram is obtained by embedding a thin-wire micro-thermocouple onto the front and rear faces of the substrate. The forced convective heat transfer coefficient as well as the net incident heat flux density brought to the substrate during the thermal spray process are estimated. The theoretical composite surface temperature is compared to the experimental recording, the result showing a good agreement.

  11. Tannin-based thin-film composite membranes for solvent nanofiltration

    KAUST Repository

    Perez Manriquez, Liliana

    2017-06-28

    The natural oligomer tannic acid was used as a reactant for an interfacial polymerisation on top of a crosslinked polyacrylonitrile (PAN) membrane. The PAN membrane was soaked with the aqueous tannic acid solution and contacted with a dilute solution of teraphtaloylchloride in hexane. Since both layers, the PAN support and the thin tannin-based layer, are highly crosslinked, the resulting thin film composite membrane is stable in harsh solvent environments such as N-Methyl-2-pyrrolidone (NMP). NMP permeances of up to 0.09L/m2 h bar with a molecular weight cut-off of approximately 800g/mol were obtained. The exceptional stability in NMP and the incorporation of natural compounds like tannic acid for the manufacture of organic solvent nanofiltration membranes provides a cost-effective alternative for industrial separations due to the simplicity of the interfacial reaction and the replacement of the commonly applied toxic aromatic amines. The scale up of the manufacturing process is not difficult; the low price of the natural tannic acid is another advantage.

  12. Development of polyelectrolyte multilayer thin film composite membrane for water desalination application

    KAUST Repository

    Fadhillah, F.

    2013-06-01

    Thin film composite membranes were fabricated via spin assisted layer by layer (SA-LbL) assembly by depositing alternate layers of poly(allyl amine hydrochloride) (PAH) and poly(acrylic acid) (PAA) on a polysulfone (PSF) ultrafiltration membrane as support. The suitability of these membranes for potential water purification applications was explored by testing the stability of the deposited thin films and their permeation characteristic using cross-flow permeation cell. Permeation test conducted at a pressure of 40bar, temperature of 25°C, pH of 6 and feed water concentration of 2000ppm NaCl demonstrated that the PAH/PAA multilayer film deposited on polysulfone support remained stable and intact under long-term test conditions. The 120 bilayers of PAH/PAA membrane tested at the above condition showed flux of 15L/m2.h and salt rejection of 65%. The membrane performance evaluation also revealed that SA-LbL PAH/PAA membrane follows the characteristics of the solution diffusion membrane. © 2013 Elsevier B.V.

  13. Solvent resistant thin film composite nanofiltration membrane: Characterization and permeation study

    Energy Technology Data Exchange (ETDEWEB)

    Minhas, Fozia T. [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Memon, Shahabuddin, E-mail: shahabuddinmemon@yahoo.com [National Center of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080 (Pakistan); Bhanger, M.I. [HEJ Research Institute of Chemistry, University of Karachi, Karachi 75270 (Pakistan); Iqbal, Nadeem; Mujahid, M. [School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology, H-12, 44000, Islamabad (Pakistan)

    2013-10-01

    The present investigation reports the fabrication of thin film composite nanofiltration (TFC-NF) membranes using interfacial polymerization technique for desalination. Ethylene diamine (EDA) and terephthaloyl chloride (TPC) were employed as aqueous and organic phase monomers, respectively to develop polyamide thin layer on the surface of Celgard 2400. The prepared membranes were characterized through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The molecular weight cutoff of TFC-NF membranes was estimated to be below 342 Da using dextrose, sucrose and raffinose solutions. A low cost dead end NF Cell was designed and manufactured domestically to conduct permeation experiments. The effect of different reaction conditions including concentration of monomers, residence time in each monomer and curing temperature on the membrane performance (water flux and MgCl{sub 2} rejection) was also studied. The water flux was augmented linearly at higher applied pressure while MgCl{sub 2} rejection was remained constant. The obtained water flux and MgCl{sub 2} rejection were measured 33 L/m{sup 2} h and 90%, respectively at 7 bar applied pressure. Beside this, membrane stability was analyzed, which confirmed the excellent constancy of ethanol and n-hexane fluxes even after an extended period. Hagen–Poiseuille equation was applied to estimate the TFC-NF membrane pore size ∼0.45 nm.

  14. STUDY ON THE DESALINATION BEHAVIORS OF PA/PSF THIN FILM COMPOSITE

    Institute of Scientific and Technical Information of China (English)

    TIAN Guojun; ZHANG Yufeng; ZHANG Yan; DU Qiyun; XIAO Changfa; GUO Hao

    2006-01-01

    A polypiperazine amide (PA)/polysulfone (PSF) thin film composite (TFC) was prepared by interfacial polymerization (IP) using a trimesoyl chloride hexane solution as the oil phase and a piperazine aqueous solution as the water phase on a porous polysulfone hollow fiber substrate. Its separating behaviors were investigated systematically to various salts such as NaCl, KCI, Na2SO4,MgCl2, CaCl2 and MgSO4, showing the highest rejection rate to Na2SO4, the second to MgSO4, the third to MgCl2 and CaCl2, and the lowest to KCI, NaCl, being 99%, 98%, 70%, 60%, 15% and 10% respectively. Under an increasing pressure or with time, the rejection rate of the TFC rises to a plateau. To various concentration of the feed, the rejection rate reduced gradually with the higher concentration.

  15. Crosslinked cellulose thin film composite nanofiltration membranes with zero salt rejection

    KAUST Repository

    Puspasari, Tiara

    2015-05-14

    We report a new synthetic route of fabricating regenerated cellulose nanofiltration membranes. The membranes are composite membranes with a thin selective layer of cellulose, which was prepared by regeneration of trimethylsilyl cellulose (a hydrophobic cellulose derivative) film followed by crosslinking. Filtration experiments using mixtures of sugar and sodium chloride showed that solutes above 300 Da were highly rejected whereas practically no rejection was observed for NaCl. This is a big advantage for a complete desalination as the existing commercial nanofiltration membranes typically exhibit NaCl rejection in the range of 30–60%. Membranes with zero NaCl rejection are required for recovery and purification applications in food, chemical and pharmaceutical industry.

  16. Cross-linked PAN-based thin-film composite membranes for non-aqueous nanofiltration

    KAUST Repository

    Pérez-Manríquez, Liliana

    2015-01-01

    A new approach on the development of cross-linked PAN based thin film composite (TFC) membranes for non-aqueous application is presented in this work. Polypropylene backed neat PAN membranes fabricated by phase inversion process were cross-linked with hydrazine to get excellent solvent stability toward dimethylformamide (DMF). By interfacial polymerization a selective polyamide active layer was coated over the cross-linked PAN using N,N′-diamino piperazine (DAP) and trimesoyl chloride (TMC) as monomers. Permeation and molecular weight cut off (MWCO) experiments using various dyes were done to evaluate the performance of the membranes. Membranes developed by such method show excellent solvent stability toward DMF with a permeance of 1.7 L/m2 h bar and a molecular weight cut-off of less than 600 Da.

  17. Photopatternable nano-composite (SU-8/ZnO) thin films for piezo-electric applications

    Science.gov (United States)

    Kandpal, Manoj; Sharan, Chandrashekhar; Poddar, Pankaj; Prashanthi, K.; Apte, Prakash R.; Ramgopal Rao, V.

    2012-09-01

    Photo-curable nanocomposite material was formulated by embedding ZnO nanoparticles into a SU-8 matrix and studied for its piezoelectric properties for low cost fabrication of self-powered nanodevices. The piezoelectric coefficient of ZnO nanoparticles was observed to be ranging between 15 and 23 pm/V, which is the highest reported. These experimental studies support the recent theoretical predictions where the piezoelectric coefficients in ZnO nanoparticles were found to be higher compared to the thin films because of the surface relaxation induced volume reductions in the nanometer scale. The photo-curable property of these polymer composite films is exploited to demonstrate fabrication of a micro-cantilever test structure.

  18. Reduction of bacterial adhesion on dental composite resins by silicon-oxygen thin film coatings.

    Science.gov (United States)

    Mandracci, Pietro; Mussano, Federico; Ceruti, Paola; Pirri, Candido F; Carossa, Stefano

    2015-01-29

    Adhesion of bacteria on dental materials can be reduced by modifying the physical and chemical characteristics of their surfaces, either through the application of specific surface treatments or by the deposition of thin film coatings. Since this approach does not rely on the use of drugs or antimicrobial agents embedded in the materials, its duration is not limited by their possible depletion. Moreover it avoids the risks related to possible cytotoxic effects elicited by antibacterial substances released from the surface and diffused in the surrounding tissues. In this work, the adhesion of Streptococcus mutans and Streptococcus mitis was studied on four composite resins, commonly used for manufacturing dental prostheses. The surfaces of dental materials were modified through the deposition of a-SiO(x) thin films by plasma enhanced chemical vapor deposition. The chemical bonding structure of the coatings was analyzed by Fourier-transform infrared spectroscopy. The morphology of the dental materials before and after the coating deposition was assessed by means of optical microscopy and high-resolution mechanical profilometry, while their wettability was investigated by contact angle measurements. The sample roughness was not altered after coating deposition, while a noticeable increase of wettability was detected for all the samples. Also, the adhesion of S. mitis decreased in a statistically significant way on the coated samples, when compared to the uncoated ones, which did not occur for S. mutans. Within the limitations of this study, a-SiO(x) coatings may affect the adhesion of bacteria such as S. mitis, possibly by changing the wettability of the composite resins investigated.

  19. Theoretical analyses of In incorporation and compositional instability in coherently grown InGaN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yayama, Tomoe [Department of Aeronautics and Astronautics, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Kangawa, Yoshihiro; Kakimoto, Koichi [Department of Aeronautics and Astronautics, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580 (Japan); Koukitu, Akinori [Division of Applied Chemistry, Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology, 184-8588, Koganei (Japan)

    2010-07-15

    We performed thermodynamic analyses to calculate the relationship between the input indium molar ratio and solid composition of a coherently grown InGaN thin film that is subjected compressive or tensile stress. The theoretical approach incorporates energy loss of a thin film system due to lattice constraint from the substrate. The results show that the indium composition x of coherently grown InGaN is lower than that of stress-free InGaN. This represents the composition pulling effect. We also studied stable growth modes under various growth conditions. The results suggest the importance of control of partial pressure of NH{sub 3} to optimize growth conditions of InGaN with a unique composition. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Synthesis of Ag-TiO2 composite nano thin film for antimicrobial application.

    Science.gov (United States)

    Yu, Binyu; Leung, Kar Man; Guo, Qiuquan; Lau, Woon Ming; Yang, Jun

    2011-03-18

    TiO2 photocatalysts have been found to kill cancer cells, bacteria and viruses under mild UV illumination, which offers numerous potential applications. On the other hand, Ag has long been proved as a good antibacterial material as well. The advantage of Ag-TiO2 nanocomposite is to expand the nanomaterial's antibacterial function to a broader range of working conditions. In this study neat TiO2 and Ag-TiO2 composite nanofilms were successfully prepared on silicon wafer via the sol-gel method by the spin-coating technique. The as-prepared composite Ag-TiO2 and TiO2 films with different silver content were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) to determine the topologies, microstructures and chemical compositions, respectively. It was found that the silver nanoparticles were uniformly distributed and strongly attached to the mesoporous TiO2 matrix. The morphology of the composite film could be controlled by simply tuning the molar ratio of the silver nitrate aqueous solution. XPS results confirmed that the Ag was in the Ag(0) state. The antimicrobial effect of the synthesized nanofilms was carried out against gram-negative bacteria (Escherichia coli ATCC 29425) by using an 8 W UV lamp with a constant relative intensity of 0.6 mW cm(-2) and in the dark respectively. The synthesized Ag-TiO2 thin films showed enhanced bactericidal activities compared to the neat TiO2 nanofilm both in the dark and under UV illumination.

  1. Synthesis of Ag-TiO2 composite nano thin film for antimicrobial application

    Science.gov (United States)

    Yu, Binyu; Leung, Kar Man; Guo, Qiuquan; Lau, Woon Ming; Yang, Jun

    2011-03-01

    TiO2 photocatalysts have been found to kill cancer cells, bacteria and viruses under mild UV illumination, which offers numerous potential applications. On the other hand, Ag has long been proved as a good antibacterial material as well. The advantage of Ag-TiO2 nanocomposite is to expand the nanomaterial's antibacterial function to a broader range of working conditions. In this study neat TiO2 and Ag-TiO2 composite nanofilms were successfully prepared on silicon wafer via the sol-gel method by the spin-coating technique. The as-prepared composite Ag-TiO2 and TiO2 films with different silver content were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) to determine the topologies, microstructures and chemical compositions, respectively. It was found that the silver nanoparticles were uniformly distributed and strongly attached to the mesoporous TiO2 matrix. The morphology of the composite film could be controlled by simply tuning the molar ratio of the silver nitrate aqueous solution. XPS results confirmed that the Ag was in the Ag0 state. The antimicrobial effect of the synthesized nanofilms was carried out against gram-negative bacteria (Escherichia coli ATCC 29425) by using an 8 W UV lamp with a constant relative intensity of 0.6 mW cm - 2 and in the dark respectively. The synthesized Ag-TiO2 thin films showed enhanced bactericidal activities compared to the neat TiO2 nanofilm both in the dark and under UV illumination.

  2. Grain Size and Wettability of TiO2/SiO2 Photocatalytic Composite Thin Films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The uniform transparent TiO2/SiO2 photocatalytic composite thin films are prepared by sol-gel method on the soda lime glass substrates, and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), BET surface area, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that the addition of SiO2 to TiO2 thin films can suppress the grain growth of TiO2 crystal, increase the hydroxyl content on the surface of TiO2 films, lower the contact angle for water on TiO2 films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 photocatalytic composite thin films with the contact angle of 0-° are obtained by the addition of 10%-20% SiO2 in mole fraction.

  3. Responsive polymer/gold nanoparticle composite thin films fabricated by solvent-induced self-assembly and spin-coating.

    Science.gov (United States)

    Li, Dongxiang; Lee, Ji Yong; Kim, Dong Ha

    2011-02-15

    Self-assembled poly(4-vinylpyridine)-grafted gold (Au) nanoparticles (NPs) and polystyrene-b-poly(4-vinylpyridine) block copolymers were fabricated by the introduction of a selective solvent to a common solution. The assembled mixtures were spin-coated onto solid substrates to fabricate composite gold/polymer thin films composed of copolymer-hybridized Au NPs and independent copolymer micelles. The obtained composite Au thin films had variable localized surface plasmon resonance (LSPR) bands and microscopic morphologies upon vapor annealing with selective solvents because the adsorption and dissolving of solvent molecules into the films could rearrange the copolymer block. The hybrid nanostructured Au thin films may have potential in vapor sensing and organic assays. Copyright © 2010 Elsevier Inc. All rights reserved.

  4. Effects of thermal treatments on chemical composition and electrical properties of ultra-thin Lu oxide layers on Si

    NARCIS (Netherlands)

    Zenkevich, A.; Lebedinskii, Yu.; Spiga, S.; Wiemer, C.; Scarel, G.; Fanciulli, M.

    2007-01-01

    The correlation between chemical composition, layered structure evolution, and electrical properties of ultra-thin (2-5 nm) Lu oxide layers grown on chemically oxidized Si(100) and exposed to different thermal treatments was monitored by x-ray photoelectron spectroscopy, x-ray reflectivity and C-V,

  5. Superhydrophilic Thin-Film Composite Forward Osmosis Membranes for Organic Fouling Control: Fouling Behavior and Antifouling Mechanisms

    KAUST Repository

    Tiraferri, Alberto

    2012-10-16

    This study investigates the fouling behavior and fouling resistance of superhydrophilic thin-film composite forward osmosis membranes functionalized with surface-tailored nanoparticles. Fouling experiments in both forward osmosis and reverse osmosis modes are performed with three model organic foulants: alginate, bovine serum albumin, and Suwannee river natural organic matter. A solution comprising monovalent and divalent salts is employed to simulate the solution chemistry of typical wastewater effluents. Reduced fouling is consistently observed for the superhydrophilic membranes compared to control thin-film composite polyamide membranes, in both reverse and forward osmosis modes. The fouling resistance and cleaning efficiency of the functionalized membranes is particularly outstanding in forward osmosis mode where the driving force for water flux is an osmotic pressure difference. To understand the mechanism of fouling, the intermolecular interactions between the foulants and the membrane surface are analyzed by direct force measurement using atomic force microscopy. Lower adhesion forces are observed for the superhydrophilic membranes compared to the control thin-film composite polyamide membranes. The magnitude and distribution of adhesion forces for the different membrane surfaces suggest that the antifouling properties of the superhydrophilic membranes originate from the barrier provided by the tightly bound hydration layer at their surface, as well as from the neutralization of the native carboxyl groups of thin-film composite polyamide membranes. © 2012 American Chemical Society.

  6. Superhydrophilic thin-film composite forward osmosis membranes for organic fouling control: fouling behavior and antifouling mechanisms.

    Science.gov (United States)

    Tiraferri, Alberto; Kang, Yan; Giannelis, Emmanuel P; Elimelech, Menachem

    2012-10-16

    This study investigates the fouling behavior and fouling resistance of superhydrophilic thin-film composite forward osmosis membranes functionalized with surface-tailored nanoparticles. Fouling experiments in both forward osmosis and reverse osmosis modes are performed with three model organic foulants: alginate, bovine serum albumin, and Suwannee river natural organic matter. A solution comprising monovalent and divalent salts is employed to simulate the solution chemistry of typical wastewater effluents. Reduced fouling is consistently observed for the superhydrophilic membranes compared to control thin-film composite polyamide membranes, in both reverse and forward osmosis modes. The fouling resistance and cleaning efficiency of the functionalized membranes is particularly outstanding in forward osmosis mode where the driving force for water flux is an osmotic pressure difference. To understand the mechanism of fouling, the intermolecular interactions between the foulants and the membrane surface are analyzed by direct force measurement using atomic force microscopy. Lower adhesion forces are observed for the superhydrophilic membranes compared to the control thin-film composite polyamide membranes. The magnitude and distribution of adhesion forces for the different membrane surfaces suggest that the antifouling properties of the superhydrophilic membranes originate from the barrier provided by the tightly bound hydration layer at their surface, as well as from the neutralization of the native carboxyl groups of thin-film composite polyamide membranes.

  7. Cantilever Beam Static and Dynamic Response Comparison with Mid-Point Bending for Thin MDF composite Panels

    Science.gov (United States)

    John F. Hunt; Houjiang Zhang; Zhiren Guo; Feng Fu

    2013-01-01

    A new cantilever beam apparatus has been developed to measure static and vibrational properties of small and thin samples of wood or composite panels. The apparatus applies a known displacement to a cantilever beam, measures its static load, then releases it into its natural first mode of transverse vibration. Free vibrational tip displacements as a function of time...

  8. Polarization Induced Changes in LSM Thin Film Electrode Composition Observed by In Operando Raman Spectroscopy and TOF-SIMS

    DEFF Research Database (Denmark)

    McIntyre, Melissa D.; Traulsen, Marie Lund; Norrman, Kion

    2015-01-01

    Polarization induced changes in LSM electrode composition were investigated by utilizing in operando Raman spectroscopy and post mortem TOF-SIMS depth profiling. Experiments were conducted on cells with 160 nm thick (La0.85Sr0.15)0.9MnO3±δ thin film electrodes in 10% O2 at 700 °C under various...

  9. The Relation Between Structure-Performance of Thin Film Composite Membranes and the Tools Used for Their Fabrication Method

    DEFF Research Database (Denmark)

    Briceno, Kelly; Javakhishvili, Irakli; Guo, Haofei

    For more than 30 years polyimides (PA) have been one of the main polymers for the fabrication of thin film composite membranes. Several researchers have assessed the main fabrication variables that influence the final structure of the polyamide layers including monomer concentration, solvents...

  10. Composition dependence of magnetic and magnetotransport properties in C60-Co granular thin films

    Science.gov (United States)

    Sugai, Isamu; Sakai, Seiji; Matsumoto, Yoshihiro; Naramoto, Hiroshi; Mitani, Seiji; Takanashi, Koki; Maeda, Yoshihito

    2010-09-01

    Composition dependence of magnetic and magnetotransport properties in C60Cox thin films exhibiting large magnetoresistance (MR) effect was investigated in the Co composition range of x =8-20, where x denotes the number of Co atoms per C60 molecule. From the superparamagnetic magnetization curves observed, the average diameter (dave) of Co nanoparticles dispersed in the matrix phase was evaluated to be approximately 1 nm for the sample of x =8, and increased with the Co composition, x. By analyzing the temperature (T) dependence of resistivity based on the model by Abeles et al. [Adv. Phys. 24, 407 (1975)], the average charging energies (⟨ÊC⟩) of Co nanoparticles were evaluated to be 2-9 meV for the samples of x =8-17 while the considerably weak temperature dependence suggested much smaller values of ⟨ÊC⟩ for the samples of x >17. The composition dependence of dave and ⟨ÊC⟩ revealed a structural transition from well-defined granular structures in the range of x =8-17 to magnetically and electronically coupled states of Co nanoparticles over x ˜17. As a result of the structural change, the MR behavior became different between the two composition regions separated at x ˜17. In particular, for the samples of x =8-17, the bias-voltage (V) dependence of the MR ratio in the low-V region fits well with an unusual exponential form of MR=MR0 exp(-V/Vc) at T proportion to ⟨ÊC⟩ and also that the fitting parameter Vc is closely correlated with ⟨ÊC⟩. These results indicate that the charging effect of Co nanoparticles plays an important role in the anomalously large MR effect of C60-Co granular films. In addition, the power-law dependence of MR on T (MR∝T-α,α˜2) was also observed at relatively high temperature range T ≥10 K in the wide range of the composition.

  11. Composition and growth procedure-dependent properties of electrodeposited CuInSe 2 thin films

    Science.gov (United States)

    Babu, S. Moorthy; Ennaoui, A.; Lux-Steiner, M. Ch.

    2005-02-01

    CuInSe 2 thin films were deposited on molybdenum-coated glass substrates by electrodeposition. Deposition was carried out with a variety of electrochemical bath compositions. The quality of the deposits depends very much on the source materials as well as the concentration of the same in the electrolyte. The deposition potential was varied from -0.4 to -0.75 V vs. SCE. The pH of the solution was adjusted to 1.5-2 using diluted sulphuric acid. Chloride salts containing bath yield good surface morphology, but there is always excess of the metallic content in the deposited films. Different growth procedures, like initial metallic layers of copper or indium, layers of copper selenide or indium selenide before the actual deposition of ternary chalcopyrite layers were attempted. Fabrication pathway, morphological and compositional changes due to the different precursor route has been analysed. The quality of the deposits prepared by one-step electrodeposition is better than the deposits with a two-stage process. The deposited films were characterized with XRD, SEM-EDAX, UV-visible spectroscopy and I- V characteristics. The deposited films were annealed in air as well as in nitrogen atmosphere. The influence of annealing temperature, environment and annealing time on the properties of the films are evaluated. Attempts were made to fabricate solar cell structure from the deposited absorber films. The structure of Mo/CuInSe 2/CdS/ZnO/Ni was characterized with surface, optical and electrical studies.

  12. Highly Hydrophilic Thin-Film Composite Forward Osmosis Membranes Functionalized with Surface-Tailored Nanoparticles

    KAUST Repository

    Tiraferri, Alberto

    2012-09-26

    Thin-film composite polyamide membranes are state-of-the-art materials for membrane-based water purification and desalination processes, which require both high rejection of contaminants and high water permeabilities. However, these membranes are prone to fouling when processing natural waters and wastewaters, because of the inherent surface physicochemical properties of polyamides. The present work demonstrates the fabrication of forward osmosis polyamide membranes with optimized surface properties via facile and scalable functionalization with fine-tuned nanoparticles. Silica nanoparticles are coated with superhydrophilic ligands possessing functional groups that impart stability to the nanoparticles and bind irreversibly to the native carboxyl moieties on the membrane selective layer. The tightly tethered layer of nanoparticles tailors the surface chemistry of the novel composite membrane without altering the morphology or water/solute permeabilities of the membrane selective layer. Surface characterization and interfacial energy analysis confirm that highly hydrophilic and wettable membrane surfaces are successfully attained. Lower intermolecular adhesion forces are measured between the new membrane materials and model organic foulants, indicating the presence of a bound hydration layer at the polyamide membrane surface that creates a barrier for foulant adhesion. © 2012 American Chemical Society.

  13. Effect of electrodeposition potential on composition and morphology of CIGS absorber thin film

    Indian Academy of Sciences (India)

    N D Sang; P H Quang; L T Tu; D T B Hop

    2013-08-01

    CuInGaSe (CIGS) thin films were deposited on Mo/soda-lime glass substrates by electrodeposition at different potentials ranging from −0.3 to −1.1 V vs Ag/AgCl. Cyclic voltammetry (CV) studies of unitary Cu, Ga, In and Se systems, binary Cu–Se, Ga–Se and In–Se systems and quaternary Cu–In–Ga–Se were carried out to understand the mechanism of deposition of each constituent. Concentration of the films was determined by energy dispersive spectroscopy. Structure and morphology of the films were characterized by X-ray diffraction and scanning electron microscope. The underpotential deposition mechanism of Cu–Se and In–Se phases was observed in voltammograms of binary and quaternary systems. Variation in composition with applied potentials was explained by cyclic voltammetry (CV) data. A suitable potential range from −0.8 to −1.0 V was found for obtaining films with desired and stable stoichiometry. In the post-annealing films, chalcopyrite structure starts forming in the samples deposited at −0.5 V and grows on varying the applied potential towards negative direction. By adjusting the composition of electrolyte, we obtained the desired stoichiometry of Cu(In0.7Ga0.3)Se2.

  14. Nano-composite thermochromic thin films and their application in energy-efficient glazing

    Energy Technology Data Exchange (ETDEWEB)

    Saeli, Manfredi [Universita degli Studi di Palermo - Dipartimento di Progetto e Costruzione Edilizia (DPCE), Viale delle Scienze, 90128 Palermo (Italy); Piccirillo, Clara; Parkin, Ivan P.; Binions, Russell [University College London - Department of Chemistry - Christopher Ingold Laboratories, 20 Gordon Street, WC1H 0AJ London (United Kingdom); Ridley, Ian [Barlett School of Graduate Studies, University College London, Wates House, 22 Gordon Street, WC1H 0QB London (United Kingdom)

    2010-02-15

    A hybrid atmospheric pressure and aerosol-assisted chemical vapour deposition strategy is presented as a facile route for the production of vanadium dioxide nano-composite thin films. The effect of the inclusion of gold nanoparticles and the use of a surfactant molecule, tetraoctylammonium bromide, is discussed. The films were fully characterised using a wide variety of techniques, including scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV/vis/NIR spectroscopy. It is shown that micro-structural changes brought about by careful control of film growth conditions, and/or the use of surfactant, lead to an enhancement of thermochromic properties. Gold nanoparticle incorporation leads to a significant change in the colour of the films from a yellow-brown colour to a variety of greens and blues depending on the gold nanoparticle concentration. The films become more reflective in the infra-red with increased gold nanoparticle incorporation. Optical data are used in energy modelling studies to elucidate the film potential as an energy-saving coating in architectural glazing. The energy modelling results suggest that for warmer climates the thermochromic nano-composites investigated here lead to significant energy savings when compared with plain glass and other standard industry products. (author)

  15. Multilayered gold-nanoparticle/polyimide composite thin film through layer-by-layer assembly.

    Science.gov (United States)

    Zhang, Fengxiang; Srinivasan, M P

    2007-09-25

    A novel type of composite thin film consisting of gold nanoparticles (AuNPs) and polymide (PI) was fabricated through layer-by-layer (LBL) assembly. To fabricate such films, bare AuNPs and a poly (amic acid) bearing pendant amine groups, namely, amino poly (amic acid) or APAA, were synthesized and assembled in an LBL fashion. Without any organic encapsulation layer on their surface, AuNPs were bound directly to APAA chains at the amine sites; X-ray photoelectron spectroscopy study suggested that the binding was based on a combined effect of metal-ligand coordination and electrostatic interaction, with the former dominating over the latter. An approximately linear growth of the film started from the second layer of AuNP as revealed by the UV-vis spectroscopy, and the degree of particle aggregation was higher in the first AuNP layer than in the subsequent layers due to the differences in the density of binding sites. The resultant assembly was heated to imidize the APAA, thereby creating a robust composite structure.

  16. Defect Characterization in a Thin Walled Composite RP-1 Tank: A Case Study

    Science.gov (United States)

    Langsing, Matthew D.; Walker, James L., II; Russell, Samual S.

    2000-01-01

    A full scale thin walled composite tank, designed and fabricated for the storage of pressurized RP- I rocket fuel, was fully inspected with digital infrared thermography (IR) during assembly and prior to proof testing. The tank featured a "pill capsule" design with the equatorial bondline being overwrapped on both the inner and outer surfaces. A composite skirt was bonded to the aft dome of the tank to serve as a structural support when the tank was stood on end in service. Numerous anomalies were detected and mapped prior to proof testing, some along bondlines and some scattered throughout the acreage. After the tank was intentionally burst, coupons were cut from the regions including thermographic anomalies. These coupons were again inspected thermographically to document the growth of any indications due to proof testing. Ultrasonic inspections (UT) were also performed on the coupons for comparison to thermography. Several coupons were dissected and micrographed. Relationships between IR and UT indications and the physical nature of the dissected material are presented.

  17. Silica-Copper Oxide Composite Thin Films as Solar Selective Coatings Prepared by Dipping Sol Gel

    Directory of Open Access Journals (Sweden)

    E. Barrera-Calva

    2008-01-01

    Full Text Available Silica-copper oxide (silica-CuO composite thin films were prepared by a dipping sol-gel route using ethanolic solutions comprised TEOS and a copper-propionate complex. Sols with different TEOS/Cu-propionate (Si/Cu molar ratios were prepared and applied on stainless steel substrates using dipping process. During the annealing process, copper-propionate complexes developed into particulate polycrystalline CuO dispersed in a partially crystallized silica matrix, as indicated by the X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS analyses. The gel thermal analysis revealed that the prepared material might be stable up to 400°C. The silica-CuO/stainless steel system was characterized as a selective absorber surface and its solar selectivity parameters, absorptance (α, and emittance (ε were evaluated from UV-NIR reflectance data. The solar parameters of such a system were mostly affected by the thickness and phase composition of the SiO2-CuO film. Interestingly, the best solar parameters (α = 0.92 and ε = 0.2 were associated to the thinnest films, which comprised a CuO-Cu2O mixture immersed in the silica matrix, as indicated by XPS.

  18. Laboratory analogues simulating Titan's atmospheric aerosols: Compared chemical compositions of grains and thin films

    Science.gov (United States)

    Carrasco, Nathalie; Jomard, François; Vigneron, Jackie; Etcheberry, Arnaud; Cernogora, Guy

    2016-09-01

    Two sorts of solid organic samples can be produced in laboratory experiments simulating Titan's atmospheric reactivity: grains in the volume and thin films on the reactor walls. We expect that grains are more representative of Titan's atmospheric aerosols, but films are used to provide optical indices for radiative models of Titan's atmosphere. The aim of the present study is to address if these two sorts of analogues are chemically equivalent or not, when produced in the same N2-CH4 plasma discharge. The chemical compositions of both these materials are measured by using elemental analysis, XPS analysis and Secondary Ion Mass Spectrometry. The main parameter probed is the CH4/N2 ratio to explore various possible chemical regimes. We find that films are homogeneous but significantly less rich in nitrogen and hydrogen than grains produced in the same experimental conditions. This surprising difference in their chemical compositions could be explained by the efficient etching occurring on the films, which stay in the discharge during the whole plasma duration, whereas the grains are ejected after a few minutes. The higher nitrogen content in the grains possibly involves a higher optical absorption than the one measured on the films, with a possible impact on Titan's radiative models.

  19. Improving the Performance and Antifouling Properties of Thin-Film Composite Membranes for Water Separation Technologies

    Science.gov (United States)

    Tiraferri, Alberto

    Membrane-based water separation processes utilize semi-permeable membranes to retain dissolved solids and contaminants. Deployment of these technologies for desalination and wastewater reuse has the potential to sustainably increase the supply of potable, agricultural, and industrial water. Despite considerable development of semi-permeable membranes in the last decades, several design obstacles hampering their progress have yet to be overcome. Specifically, major membrane improvements are currently sought with respect to their performance and productivity, as well as their resistance to fouling. This dissertation research aims at the advancement of semi-permeable membranes by rational optimization of their design to: (i) understand and improve their transport properties and (ii) reduce fouling by organic molecules and delay biofouling by microorganisms. In particular, thin-film composite polyamide membranes for both reverse osmosis and forward osmosis processes are the main target of the investigation. The structural and physicochemical properties of thin-film composite membranes are both characterized and tailored through implementation of original techniques and novel functionalization protocols. The membrane structure and morphology are rationally modified to enhance the mass transport within the support layer. The influence of fabrication conditions on support layer formation and on its final structure is elucidated. The intricate interrelationship among the performance of the different layers of the composite membrane is highlighted and a new protocol is developed to characterize the transport properties of membranes deployed in forward osmosis processes. Novel approaches to impart targeted properties to the active surface of thin-film composite membranes are also proposed. The functionalization is achieved by exploiting the inherent moieties of the polyamide layer to irreversibly bind nanomaterials with desired properties. An experimental method to determine

  20. Scalable fabrication of multifunctional freestanding carbon nanotube/polymer composite thin films for energy conversion.

    Science.gov (United States)

    Li, Xiaokai; Gittleson, Forrest; Carmo, Marcelo; Sekol, Ryan C; Taylor, André D

    2012-02-28

    Translating the unique properties of individual single-walled carbon nanotubes (SWNTs) to the macroscale while simultaneously incorporating additional functionalities into composites has been stymied by inadequate assembly methods. Here we describe a technique for developing multifunctional SWNT/polymer composite thin films that provides a fundamental engineering basis to bridge the gap between their nano- and macroscale properties. Selected polymers are infiltrated into a Mayer rod coated conductive SWNT network to fabricate solar cell transparent conductive electrodes (TCEs), fuel cell membrane electrode assemblies (MEAs), and lithium ion battery electrodes. Our TCEs have an outstanding optoelectronic figure of merit σ(dc)/σ(ac) of 19.4 and roughness of 3.8 nm yet are also mechanically robust enough to withstand delamination, a step toward scratch resistance necessary for flexible electronics. Our MEAs show platinum utilization as high as 1550 mW/mg(Pt), demonstrating our technique's ability to integrate ionic conductivity of the polymer with electrical conductivity of the SWNTs at the Pt surface. Our battery anodes, which show reversible capacity of ∼850 mAh/g after 15 cycles, demonstrate the integration of electrode and separator to simplify device architecture and decrease overall weight. Each of these applications demonstrates our technique's ability to maintain the conductivity of SWNT networks and their dispersion within a polymer matrix while concurrently optimizing key complementary properties of the composite. Here, we lay the foundation for the assembly of nanotubes and nanostructured components (rods, wires, particles, etc.) into macroscopic multifunctional materials using a low-cost and scalable solution-based processing technique.

  1. Photocatalytic Activity of Vis-Responsive Ag-Nanoparticles/TiO2 Composite Thin Films Fabricated by Molecular Precursor Method (MPM

    Directory of Open Access Journals (Sweden)

    Mitsunobu Sato

    2013-07-01

    Full Text Available The Ag-nanoparticles (Ag-NP/TiO2 composite thin films with various amounts of Ag (10 mol% ≤ n ≤ 80 mol% were examined as a potential photocatalyst by decoloration reaction of methylene blue (MB in an aqueous solution. These composite thin films of ca. 100 nm thickness were fabricated by the MPM at 600 °C in air. The decoloration rates monitored by the absorption intensity of the MB solution indicated that the composite thin films of Ag with an amount less than 40 mol% are not effective under vis-irradiation, though they can work as a photocatalyst under UV-irradiation. Further, the UV-sensitivity of the composite thin films gradually decreased to almost half the level of that of the TiO2 thin film fabricated under the identical conditions when the Ag amount increased from 10 to 40 mol%. Contrarily, the composite thin films of Ag content larger than 50 mol% showed the vis-responsive activity, whose level was slightly lower than the decreased UV-sensitivity. Diffuse reflectance spectra suggested that the vis-responsive activity of the composite thin films is due to the conductivity, localized surface plasmon resonance and surface plasmon resonance of Ag-NP. It was also elucidated that the vis-responsive level of the composite thin films corresponds to their electrical conductivity that depends on the Ag content.

  2. Rapid mixing chemical oxidative polymerization: an easy route to prepare PANI coated small-diameter CNTs/PANI nanofibres composite thin film

    Indian Academy of Sciences (India)

    G Venkata Ramana; Balaji Padya; Vadali V S S Srikanth; P K Jain

    2014-05-01

    Composite thin film containing polyaniline (PANI) coated small diameter carbon nanotubes (SDCNTs)/PANI nanofibres (NFs) has been prepared using an easy in situ rapid mixing chemical oxidative polymerization method. SDCNTs thin film was obtained using thermal chemical vapour deposition method in a separate experiment, whilst PANI NFs are formed in situ during the synthesis of composite. In the composite, PANI coated SDCNTs are uniformly distributed among PANI NFs. The presence of SDCNTs during the composite synthesis does not influence the nucleation and growth of PANI NFs. Raman analysis shows a good interaction between PANI and SDCNTs. Room temperature d.c. electrical sheet resistance of SDCNTs/PANI NFs composite thin film surface is three orders lesser than that of PANI NFs thin film (PANI NFs have the same morphology as in the composite) synthesized using the same method but without the presence of SDCNTs.

  3. Changes in chemical composition and nanostructure of SiC thin films prepared by PECVD during thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Kuenle, Matthias; Janz, Stefan [Fraunhofer Institute of Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Nickel, Klaus Georg [Applied Mineralogy, Institute for Geosciences, Eberhard-Karl-University Tuebingen, Wilhelmstr. 52, 72074 Tuebingen (Germany); Eibl, Oliver [Institute for Applied Physics, Eberhard-Karls-University Tuebingen, Auf der Morgenstelle 10, 72074 Tuebingen (Germany)

    2011-08-15

    Silicon carbide (SiC) thin films were deposited on silicon (Si) using plasma enhanced chemical vapor deposition (PECVD). Annealing was done in a rapid thermal annealing furnace at a temperature of 1300 C. As-deposited and annealed Si-rich and stoichiometric SiC thin films were investigated by analytical transmission electron microscopy (AEM). TEM-energy-dispersive X-ray spectroscopy was used to quantify the chemical composition of the SiC thin films with high accuracy. The chemical composition of the near stoichiometric SiC thin film changed during annealing from Si{sub 0.4}C{sub 0.6} to Si{sub 0.5}C{sub 0.5} due to diffusion of Si from the Si substrate into the film. The Si-rich Si{sub 1-x}C{sub x} film had the identical chemical composition of Si{sub 0.8}C{sub 0.2} before and after annealing. As-deposited films show nanoporosity within the bulk film. During annealing, v-shaped defect structures were formed at the interface of the stoichiometric SiC thin film to the Si substrate. Diffraction patterns revealed that as-deposited films were amorphous. During annealing the crystallization of 3C-SiC occurred in near-stoichiometric SiC thin films, whereas in Si-rich Si{sub 1-x}C{sub x} thin films two phases, namely Si and 3C-SiC, crystallized. Low-loss and core-loss electron energy loss spectroscopy (EELS) verified the diffraction results. In the low-loss spectra of the near stoichiometric SiC thin film, a plasmon peak located at 20.2 eV before and at 22.3 eV after annealing was detected. The low-loss spectra of the Si-rich Si{sub 1-x}C{sub x} thin film showed an asymmetric plasmon peak with two maxima located at 18.5 and 25.0 eV in the as-deposited film and 18.6 and 24.3 eV in the annealed Si-rich Si{sub 1-x}C{sub x} film. The 18.5 eV plasmon peaks is assigned to Si and the 25 eV plasmon peak is attributed to the SiC phase. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Composite thinning algorithm for fingerprint image%指纹图像细化的复合式算法

    Institute of Scientific and Technical Information of China (English)

    卞维新; 徐德琴

    2011-01-01

    Fingerprint image thinning is an essential step in the fingerprint recognition system, which plays a key role in the feature extraction. In order to thin the fingerprint image efficiently, we analyze the underlying causes of the disadvantages of the existing fast parallel thinning algorithm and the improved OPTA thinning algorithm, and then present a new composite fingerprint image thinning algorithm is presented in this paper. A set of preprocessing templates are designed to smooth images after fast thinning. In addition, the improved OPTA algorithm is optimized for speed. A large number of experimental results show that, the presented algorithm has high thinning speed, and can obtain good thinning quality.%指纹图像细化是指纹识别算法中的重要环节,对特征提取起到关键作用.为了快速和高质量地对指纹图像进行细化,对快速细化算法和改进OPTA细化算法不足产生的内在原因进行分析,提出一种新的复合式指纹图像细化算法,该算法设计一套预处理模板,避免了快速细化算法形成的毛刺,并对改进OPTA算法进行了优化.大量实验结果表明,该算法不但具有以往算法的优点,有较好的细化速度,而且细化质量有显著地提高,细化后的图像光滑几乎无毛刺.

  5. Functionalized Antimicrobial Composite Thin Films Printing for Stainless Steel Implant Coatings.

    Science.gov (United States)

    Floroian, Laura; Ristoscu, Carmen; Mihailescu, Natalia; Negut, Irina; Badea, Mihaela; Ursutiu, Doru; Chifiriuc, Mariana Carmen; Urzica, Iuliana; Dyia, Hussien Mohammed; Bleotu, Coralia; Mihailescu, Ion N

    2016-06-09

    In this work we try to address the large interest existing nowadays in the better understanding of the interaction between microbial biofilms and metallic implants. Our aimed was to identify a new preventive strategy to control drug release, biofilm formation and contamination of medical devices with microbes. The transfer and printing of novel bioactive glass-polymer-antibiotic composites by Matrix-Assisted Pulsed Laser Evaporation into uniform thin films onto 316 L stainless steel substrates of the type used in implants are reported. The targets were prepared by freezing in liquid nitrogen mixtures containing polymer and antibiotic reinforced with bioglass powder. The cryogenic targets were submitted to multipulse evaporation by irradiation with an UV KrF* (λ = 248 nm, τFWHM ≤ 25 ns) excimer laser source. The prepared structures were analyzed by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and profilometry, before and after immersion in physiological fluids. The bioactivity and the release of the antibiotic have been evaluated. We showed that the incorporated antibiotic underwent a gradually dissolution in physiological fluids thus supporting a high local treatment efficiency. Electrochemical measurements including linear sweep voltammetry and impedance spectroscopy studies were carried out to investigate the corrosion resistance of the coatings in physiological environments. The in vitro biocompatibility assay using the MG63 mammalian cell line revealed that the obtained nanostructured composite films are non-cytotoxic. The antimicrobial effect of the coatings was tested against Staphylococcus aureus and Escherichia coli strains, usually present in implant-associated infections. An anti-biofilm activity was evidenced, stronger against E. coli than the S. aureus strain. The results proved that the applied method allows for the fabrication of implantable biomaterials which shield metal ion release and possess

  6. Functionalized Antimicrobial Composite Thin Films Printing for Stainless Steel Implant Coatings

    Directory of Open Access Journals (Sweden)

    Laura Floroian

    2016-06-01

    Full Text Available In this work we try to address the large interest existing nowadays in the better understanding of the interaction between microbial biofilms and metallic implants. Our aimed was to identify a new preventive strategy to control drug release, biofilm formation and contamination of medical devices with microbes. The transfer and printing of novel bioactive glass-polymer-antibiotic composites by Matrix-Assisted Pulsed Laser Evaporation into uniform thin films onto 316 L stainless steel substrates of the type used in implants are reported. The targets were prepared by freezing in liquid nitrogen mixtures containing polymer and antibiotic reinforced with bioglass powder. The cryogenic targets were submitted to multipulse evaporation by irradiation with an UV KrF* (λ = 248 nm, τFWHM ≤ 25 ns excimer laser source. The prepared structures were analyzed by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy and profilometry, before and after immersion in physiological fluids. The bioactivity and the release of the antibiotic have been evaluated. We showed that the incorporated antibiotic underwent a gradually dissolution in physiological fluids thus supporting a high local treatment efficiency. Electrochemical measurements including linear sweep voltammetry and impedance spectroscopy studies were carried out to investigate the corrosion resistance of the coatings in physiological environments. The in vitro biocompatibility assay using the MG63 mammalian cell line revealed that the obtained nanostructured composite films are non-cytotoxic. The antimicrobial effect of the coatings was tested against Staphylococcus aureus and Escherichia coli strains, usually present in implant-associated infections. An anti-biofilm activity was evidenced, stronger against E. coli than the S. aureus strain. The results proved that the applied method allows for the fabrication of implantable biomaterials which shield metal ion release

  7. Preparation and performance of thin-layered PdAu/ceramic composite membranes

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Lei; Goldbach, Andreas; Zeng, Gaofeng; Xu, Hengyong [Dalian Institute of Chemical Physics, Chinese Academy of Science, Zhongshan Road 457, Dalian 116023 (China)

    2010-05-15

    Preparation of 3-5 {mu}m thick, hydrogen-selective PdAu layers via sequential electroless plating of Pd and Au onto ceramic microfiltration membranes was investigated employing a cyanide-free Au plating bath. The Au deposition rate was strongly dependent on bath temperature and alkalinity reaching an optimum at 333 K and pH 10. Homogenous alloying of the separate metal layers under atmospheric H{sub 2} proved to be a protracted process and required approximately a week at 873 K for a PdAu layer as thin as 3 {mu}m. After 300 h annealing at 823 K the 5 {mu}m thick PdAu layer of a composite membrane still exhibited a Au gradient declining from 7.4 at.% at the top surface to 5.5 at.% at the support interface despite that the H{sub 2} permeation rate had become stable. Nonetheless, the membrane exhibited a very high H{sub 2} permeability of e.g. 1.3 x 10{sup -8} mol m m{sup -2} s{sup -1} Pa{sup -0.5} at 673 K, but it decreased much faster with temperature below 573 K than above, likely due to a change from bulk H diffusion-controlled to H{sub 2} adsorption or desorption-limited transport. The composite membrane withstood cycling between 523 and 723 K in H{sub 2} well showing that differing thermal expansion of the joined metallic and ceramic materials stayed within the tolerance range up to 723 K. (author)

  8. Plasma interactions determine the composition in pulsed laser deposited thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jikun; Stender, Dieter; Conder, Kazimierz; Wokaun, Alexander; Schneider, Christof W.; Lippert, Thomas, E-mail: thomas.lippert@psi.ch [Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland); Döbeli, Max [Laboratory of Ion Beam Physics, ETH Zurich, CH-8093 Zurich (Switzerland)

    2014-09-15

    Plasma chemistry and scattering strongly affect the congruent, elemental transfer during pulsed laser deposition of target metal species in an oxygen atmosphere. Studying the plasma properties of La{sub 0.6}Sr{sub 0.4}MnO{sub 3}, we demonstrate for as grown La{sub 0.6}Sr{sub 0.4}MnO{sub 3-δ} films that a congruent transfer of metallic species is achieved in two pressure windows: ∼10{sup −3} mbar and ∼2 × 10{sup −1} mbar. In the intermediate pressure range, La{sub 0.6}Sr{sub 0.4}MnO{sub 3-δ} becomes cation deficient and simultaneously almost fully stoichiometric in oxygen. Important for thin film growth is the presence of negative atomic oxygen and under which conditions positive metal-oxygen ions are created in the plasma. This insight into the plasma chemistry shows why the pressure window to obtain films with a desired composition and crystalline structure is narrow and requires a careful adjustment of the process parameters.

  9. Surface Functionalization of Thin-Film Composite Membranes with Copper Nanoparticles for Antimicrobial Surface Properties

    KAUST Repository

    Ben-Sasson, Moshe

    2014-01-07

    Biofouling is a major operational challenge in reverse osmosis (RO) desalination, motivating a search for improved biofouling control strategies. Copper, long known for its antibacterial activity and relatively low cost, is an attractive potential biocidal agent. In this paper, we present a method for loading copper nanoparticles (Cu-NPs) on the surface of a thin-film composite (TFC) polyamide RO membrane. Cu-NPs were synthesized using polyethyleneimine (PEI) as a capping agent, resulting in particles with an average radius of 34 nm and a copper content between 39 and 49 wt.%. The positive charge of the Cu-NPs imparted by the PEI allowed a simple electrostatic functionalization of the negatively charged RO membrane. We confirmed functionalization and irreversible binding of the Cu-NPs to the membrane surface with SEM and XPS after exposing the membrane to bath sonication. We also demonstrated that Cu-NP functionalization can be repeated after the Cu-NPs dissolve from the membrane surface. The Cu-NP functionalization had minimal impact on the intrinsic membrane transport parameters. Surface hydrophilicity and surface roughness were also maintained, and the membrane surface charge became positive after functionalization. The functionalized membrane exhibited significant antibacterial activity, leading to an 80-95% reduction in the number of attached live bacteria for three different model bacterial strains. Challenges associated with this functionalization method and its implementation in RO desalination are discussed. © 2013 American Chemical Society.

  10. Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    H Ma; B Hsiao; B Chu

    2011-12-31

    The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

  11. Composite thin film by hydrogen-bonding assembly of polymer brush and poly(vinylpyrrolidone).

    Science.gov (United States)

    Yang, Shuguang; Zhang, Yongjun; Wang, Li; Hong, Song; Xu, Jian; Chen, Yongming; Li, Chengming

    2006-01-03

    Based on hydrogen-bonding layer-by-layer (LBL) assembly in aqueous solution, poly(vinylpyrrolidone) (PVPON) and a spherical polymer brush with a poly(methylsilsesquioxane) (PSQ) core and poly(acrylic acid) (PAA) hair chains were used to fabricate composite multilayer thin films. Hydrogen bonding as the driving force was confirmed by FT-IR spectrometry. A simple method (Filmetric F20) was introduced to determine the thickness and refractive index of the films. The film thickness was found to be a linear function of the number of bilayers. The average increase in thickness per bilayer is 28.3 nm. The film morphology was characterized with scanning electron microscopy and atomic force microscopy. The images obtained from the two instruments show a great resemblance. The films were further calcined to get an inorganic film by removing the organic components, or treated with tetrabutylammonium fluoride (TBAF) to remove the PSQ core and get an organic film. The optical properties and morphological changes induced by these treatments were also studied.

  12. Optical and physical properties of different composition of In xSe 1-x thin films

    Science.gov (United States)

    El-Kabnay, N.; Shaaban, E. R.; Afify, N.; Abou-sehly, A. M.

    2008-01-01

    Thin film binary alloys of In xSe 1-x (0.05⩽ x⩽0.30) have been prepared by the thermal evaporation technique. The optical transmission and reflection spectrum of these films were measured in the range 300-1100 nm. Both refractive index, n and extinction coefficient k have been determined from transmission and reflection measurements in terms of Murmann's equations. The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple-DiDomenico model. The width of band tail is determined and the optical absorption edge is described using the ‘non-direct transition’ model proposed by Tauc. Finally, the relationship between the optical gap and chemical composition in In xSe 1-x amorphous system is discussed in terms of the average heat of atomization Hs and average coordination number Nc. The results of these calculations can be used rationalize the observed optical properties of these materials. Finally, the chemical bond approach has been also applied to interpret the decrease of the glass optical gap with increasing In content.

  13. Sustainable Antibiofouling Properties of Thin Film Composite Forward Osmosis Membrane with Rechargeable Silver Nanoparticles Loading.

    Science.gov (United States)

    Liu, Zhongyun; Hu, Yunxia

    2016-08-24

    Microbial attachment and biofilm formation on filtration membrane can greatly compromise its flux and separation efficiency. Here, a simple and facile approach has been developed to in situ generate silver nanoparticles (Ag NPs) on the thin film composite forward osmosis (TFC FO) membrane for sustainable antibiofouling performances. Mussel-inspired dopamine chemistry was applied to grow polydopamine coating on both surfaces of FO membranes, followed by the generation of Ag NPs upon a simple dip coating in silver nitrate aqueous solution. Furthermore, the Ag NPs deposited membranes had a long-term silver release profile with rechargability for multiple times upon their depletion, and exhibited strong sustainable bactericidal efficacy against Gram-negative bacteria and Gram-positive bacteria. The Ag NPs had a controllable effect on the membrane performances including the water flux and reverse salt flux in the FO test mode. Our practicable antibacterial strategy may apply to other types of filtration membranes with diverse material surfaces and may pave a new way to achieve the sustainable membrane antibiofouling performance on a large scale.

  14. Composition and morphological characteristics of chemically sprayed fluorine-doped zinc oxide thin films deposited on Si(1 0 0)

    Energy Technology Data Exchange (ETDEWEB)

    Castaneda, L. [Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-186, 04510 D. F. (Mexico); Departamento de Fisica y Matematicas, Division de Ciencia, Arte y Tecnologia, Universidad Iberoamericana, Av. Prolongacion Paseo de la Reforma 880, Santa Fe 012100, D. F. (Mexico); Maldonado, A. [Depto. de Ing. Electrica, CINVESTAV IPN, SEES, Apartado Postal 14740, Mexico, D.F. 07000 (Mexico); Cheang-Wong, J.C. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, Mexico, D.F. 01000 (Mexico); Terrones, M. [Advanced Materials Department, IPICYT, Camino a la Presa San Jose 2055, Col. Lomas, 4a. seccion, San Luis Potosi, 78216 (Mexico); Departamento de Fisica y Matematicas, Division de Ciencia, Arte y Tecnologia, Universidad Iberoamericana, Av. Prolongacion Paseo de la Reforma 880, Santa Fe 012100, D. F. (Mexico); Olvera, M. de la L [Depto. de Ing. Electrica, CINVESTAV IPN, SEES, Apartado Postal 14740, Mexico, D.F. 07000 (Mexico)]. E-mail: molvera@cinvestav.mx

    2007-03-01

    Fluorine-doped zinc oxide thin films (ZnO:F) were deposited on Si(1 0 0) substrates by the chemical spray technique (CST) from an aged-solution. The effect of the substrate temperature on the morphology and composition of the ZnO:F thin films was studied. The films were polycrystalline, with a preferential growth along the ZnO (0 0 2) plane, irrespective of the deposition temperature. The average crystal size within the films was ca. 35 nm and the morphology of the surface was found to be dependent on the substrate temperature. At low substrate temperatures irregular-shaped grains were observed, whereas at higher temperatures uniform flat grains were obtained. Elemental analysis showed that the composition of the films is close to stoichiometric ZnO and that samples contain quite a low fluorine concentration, which decreases as a function of the deposition temperature.

  15. Quantitative compositional analysis of organic thin films using transmission NEXAFS spectroscopy in an X-ray microscope

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Brian A. [Department of Physics, NCSU, Raleigh, NC 27695-8202 (United States); Ade, Harald, E-mail: harald_ade@ncsu.edu [Department of Physics, NCSU, Raleigh, NC 27695-8202 (United States)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer Common sources of error in transmission NEXAFS spectra in a STXM identified and shown to be significant. Black-Right-Pointing-Pointer Three facile methods to characterize and eliminate or limit errors are detailed. Black-Right-Pointing-Pointer Appropriate spectra processing methods are discussed and demonstrated. Black-Right-Pointing-Pointer Quantitative compositional analysis of organic thin films is conducted and shown to be robust. -- Abstract: Near edge X-ray absorption fine structure (NEXAFS) spectroscopy is well suited for the quantitative determination of the composition of soft matter thin films. Combined with the high spatial resolution of a scanning transmission X-ray microscope, compositional maps of submicron morphologies can be derived and have been used successfully to characterize a number of materials systems. However, multiple sources of known systematic errors limit the accuracy and are frequently not taken into account. We show that these errors can be significant (more than 10%) and demonstrate simple methods to eliminate them. With suitable precautions, a compositional measurement can be made on a thin film sample in a matter of minutes with sub-micron spatial resolution and sub-percent compositional precision. NEXAFS measurements are furthermore known to be sensitive to anisotropic molecular orientation and a strategy to account for that and extract preferential molecular orientation relative to a reference is presented. The spatial resolution of the measurement can be increased to below 100 nm at the expense of compositional precision, depending on the point spread function of the zone plate focusing optics of the microscope.

  16. Optically optimal wavelength-scale patterned ITO/ZnO composite coatings for thin film solar cells

    CERN Document Server

    Moreau, Antoine; Centeno, Emmanuel; Seassal, Christian

    2012-01-01

    A new methodology is proposed for finding structures that are, optically speaking, locally optimal : a physical analysis of much simpler structures is used to constrain the optimization process. The obtained designs are based on a flat amorphous silicon layer (to minimize recombination) with a patterned anti-reflective coating made of ITO or ZnO, or a composite ITO/ZnO coating. These latter structures are realistic and present good performances despite very thin active layers.

  17. Tungsten-rhenium thin film thermocouples for SiC-based ceramic matrix composites

    Science.gov (United States)

    Tian, Bian; Zhang, Zhongkai; Shi, Peng; Zheng, Chen; Yu, Qiuyue; Jing, Weixuan; Jiang, Zhuangde

    2017-01-01

    A tungsten-rhenium thin film thermocouple is designed and fabricated, depending on the principle of thermal-electric effect caused by the high temperature. The characteristics of thin film thermocouples in different temperatures are investigated via numerical analysis and analog simulation. The working mechanism and thermo-electric features of the thermocouples are analyzed depending on the simulation results. Then the thin film thermocouples are fabricated and calibrated. The calibration results show that the thin film thermocouples based on the tungsten-rhenium material achieve ideal static characteristics and work well in the practical applications.

  18. Electron-Induced Secondary Electron Emission Properties of MgO/Au Composite Thin Film Prepared by Magnetron Sputtering

    Science.gov (United States)

    Li, Jie; Hu, Wenbo; Wei, Qiang; Wu, Shengli; Hua, Xing; Zhang, Jintao

    2016-12-01

    As a type of electron-induced secondary electron emitter, MgO/Au composite thin film was prepared by reactive magnetron sputtering of individual Mg target and Au target, and the effects of key process parameters on its surface morphology and secondary electron emission (SEE) properties were investigated. It is found that to deposit a NiO buffer layer on the substrate is conducive to the subsequent growth of MgO grains owing to the lattice matching. The gold addition can raise the electrical conductivity of MgO film and further suppress the surface charging. However, the gold deposition would interfere with the MgO crystallization and increase the surface roughness of MgO/Au film. Therefore, MgO/Au composite thin film with a NiO buffer layer and proper deposition times of MgO and Au can achieve superior SEE properties due to good MgO crystallization, low surface roughness and reasonable electrical conductivity. The optimized MgO/Au composite thin film has a higher SEE coefficient and a lower 1-h SEE degradation rate under electron beam bombardment in comparison with MgO film.

  19. Assembly of europium organic framework–gold nanoparticle composite thin films on silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Deep, Akash, E-mail: dr.akashdeep@gmail.com [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030 (India); Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30 C, Chandigarh 160030 (India); Kaur, Rajnish [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030 (India); Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30 C, Chandigarh 160030 (India); Kumar, Parveen [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030 (India); Kumar, Pawan; Paul, A.K. [Central Scientific Instruments Organisation (CSIR-CSIO), Sector 30 C, Chandigarh 160030 (India); Academy of Scientific and Innovative Research, CSIR-CSIO, Sector 30 C, Chandigarh 160030 (India)

    2014-08-28

    Metal organic frameworks are a sub-class of coordination polymers and rapidly generating huge research interests in several technological areas. One of the emerging areas of their potential applications is the photovoltaics. The present study proposes the assembly of europium organic framework–gold nanoparticle nanocomposite thin film on silicon substrate. Microscopic, X-ray diffraction, surface area measurement and thermal studies have indicated the formation of the desired thin film. Spectral studies have been used to highlight their solid state optical property. Current–voltage studies have established semiconducting property of the above thin films. - Highlights: • Thin film of europium organic framework/gold nanoparticles is prepared on silicon. • Fairly homogeneous films with a roughness factor of 5–10 nm are obtained. • Above thin films offer solid-state photoluminescence and semiconducting properties.

  20. Compositional analysis of electrodeposited bismuth telluride thermoelectric thin films using combined electrochemical quartz crystal microgravimetry--stripping voltammetry.

    Science.gov (United States)

    Ham, Sunyoung; Jeon, Soyeon; Lee, Ungki; Park, Minsoon; Paeng, Ki-Jung; Myung, Noseung; Rajeshwar, Krishnan

    2008-09-01

    Bismuth telluride (Bi 2Te 3 ) is a benchmark material for thermoelectric power generation and cooling applications. Electrodeposition is a versatile technique for preparing thin films of this material; however, it affords films of variable composition depending on the preparation history. A simple and rapid assay of electrodeposited films, therefore, has both fundamental and practical importance. In this study, a new protocol for the electroanalysis of Bi 2Te 3 thin films is presented by combining the two powerful and complementary techniques of electrochemical quartz crystal microgravimetry (EQCM) and stripping voltammetry. First, any free (and excess) tellurium in the electrodeposited film was reduced to soluble Te ( 2- ) species by scanning to negative potentials in a 0.1 M Na 2SO 4 electrolyte, and the accompanying frequency increase (mass loss) was used to determine the content of free tellurium. The film was again subjected to cathodic stripping in the same medium (to generate Bi (0) and soluble Te (2-) from the Bi 2 Te 3 film component of interest), and the EQCM frequency change was used to determine the content of chemically bound Te in the Bi 2Te 3 thin film and thereby the compound stoichiometry. Finally, the EQCM frequency change during Bi oxidation to Bi (3+) and the difference between total Bi and Bi in Bi 2Te 3 resulted in the assay of free (excess) Bi in the electrodeposited film. Problems associated with the chemical/electrochemical stability of the free Bi species were circumvented by a flow electroanalysis approach. Data are also presented on the sensitivity of electrodeposited Bi 2Te 3 film composition to the electrodeposition potential. This newly developed method can be used for the compositional analysis of other thermoelectric thin-film material candidates in general.

  1. Preparation and properties of thin epoxy/compressed expanded graphite composite bipolar plates for proton exchange membrane fuel cells

    Science.gov (United States)

    Du, Chao; Ming, Pingwen; Hou, Ming; Fu, Jie; Shen, Qiang; Liang, Dong; Fu, Yunfeng; Luo, Xiaokuan; Shao, Zhigang; Yi, Baolian

    Although the composite bipolar plates prepared by the method of the vacuum resin impregnation in compressed expanded graphite (CEG) sheets have been applied in the KW-class stacks, there have been few investigations of the preparation and properties of them so far. In this research, the influences of the microstructure on the physical properties of the thin epoxy/CEG composites (the thickness is 1 mm) are investigated for the first time and the optimum preparation conditions are obtained. Results demonstrated that the mechanical property and the impermeability of the composites increases evidently with the resin content changing from 4% to 30%, while the electrical properties keep nearly constant. It can be attributed to the continuous expanded graphite (EG) conductive network of the raw CEG sheet. The epoxy (30 wt.%)/CEG composite is shown to be the optimum composite, displaying in-plane conductivity of 119.8 S cm -1, through-plane resistance of 17.13 mΩ cm 2, density of 1.95 g cm -3, gas permeability of 1.94 × 10 -6 cm 3 cm -2 s -1 and flexural strength of 45.8 MPa. The alcohol scrubbing is the optimum method of surface post-processing. The performance of a single cell with the optimum composite bipolar plates is tested and demonstrated to be outstanding. Above all, the composite prepared by resin vacuum impregnation in the CEG sheet is a promising candidate for bipolar plate materials in PEMFCs.

  2. Nonlinear optical properties of polyaniline and poly (o-toluidine) composite thin films with multi walled carbon nano tubes

    Science.gov (United States)

    Nagaraja, K. K.; Pramodini, S.; Poornesh, P.; Telenkov, M. P.; Kityk, I. V.

    2017-05-01

    We report the improved third-order nonlinear optical properties of polyaniline and poly (o-toluidine) with different doping concentrations of multi walled carbon nano tube (MWCNTs) composite thin films investigated using z-scan technique and continuous wave He-Ne laser at 633 nm wavelength was used as source of excitation. Thin films were prepared by spin coating technique on glass substrate. The structural properties of the composite films were analysed by X-ray diffraction studies and the characteristic peaks corresponding to MWCNTs and polymers have been observed. The surface morphology of the deposited films was analysed using scanning electron microscopy and it confirms that the polymer in the composites has been coated on the MWCNTs homogeneously. The z-scan results reveal that the films exhibit reverse saturable absorption and self-defocusing nonlinearity. The third-order nonlinear optical susceptibility χ(3) is found to be of the order of 10-3 esu. Also, optical power limiting and clamping experiment was performed. The clamping values increases with increase in concentration and the lowest clamping observed for composite films are 1 mW and 0.7 mW.

  3. Nonlinear optical properties of polyaniline and poly (o-toluidine) composite thin films with multi walled carbon nano tubes

    Energy Technology Data Exchange (ETDEWEB)

    Nagaraja, K.K. [National University of Science and Technology “MISiS”, Leninskii pr. 4, Moscow 119049 (Russian Federation); Pramodini, S. [Department of Physics, School of Engineering and Technology, Jain University, Jakkasandra Post, Bengaluru 5621112, Karnataka (India); Poornesh, P., E-mail: poorneshp@gmail.com [Nonlinear Optics Research Laboratory, Department of Physics, Manipal Institute of Technology, Manipal University, Manipal 576 104, Karnataka (India); Telenkov, M.P. [National University of Science and Technology “MISiS”, Leninskii pr. 4, Moscow 119049 (Russian Federation); Kityk, I.V. [Electrical Engineering Department, Czestochowa University Technology, Czestochowa (Poland)

    2017-05-01

    We report the improved third-order nonlinear optical properties of polyaniline and poly (o-toluidine) with different doping concentrations of multi walled carbon nano tube (MWCNTs) composite thin films investigated using z-scan technique and continuous wave He–Ne laser at 633 nm wavelength was used as source of excitation. Thin films were prepared by spin coating technique on glass substrate. The structural properties of the composite films were analysed by X-ray diffraction studies and the characteristic peaks corresponding to MWCNTs and polymers have been observed. The surface morphology of the deposited films was analysed using scanning electron microscopy and it confirms that the polymer in the composites has been coated on the MWCNTs homogeneously. The z-scan results reveal that the films exhibit reverse saturable absorption and self-defocusing nonlinearity. The third-order nonlinear optical susceptibility χ{sup (3)} is found to be of the order of 10{sup −3} esu. Also, optical power limiting and clamping experiment was performed. The clamping values increases with increase in concentration and the lowest clamping observed for composite films are 1 mW and 0.7 mW.

  4. Compositional dependence of Pb(Mg1/3,Nb2/3)O3-PbTiO3 piezoelectric thin films by combinatorial sputtering

    Science.gov (United States)

    Kurokawa, Fumiya; Tsujiura, Yuichi; Hida, Hirotaka; Kanno, Isaku

    2014-09-01

    We evaluated the compositional dependence of Pb(Mg1/3,Nb2/3)O3-PbTiO3 (PMN-PT) polycrystalline thin films by combinatorial sputtering. We prepared compositional gradient (1 - x)PMN-xPT polycrystalline thin films with preferential orientation along the direction in the composition range of x = 0-0.62. We determined that the morphotropic phase boundary (MPB) composition of PMN-PT polycrystalline thin film existed at around x = 0.35, from the X-ray diffraction (XRD) measurements. The maximum value of relative dielectric constants (ɛr = 1498) was obtained at approximately x = 0.23. On the other hand, the piezoelectric coefficients (|e31,f| = 14.1 C/m2) peaked at the determined MPB composition of x = 0.35. From the results of the compositional dependence of dielectric and piezoelectric characteristics, the FOM (e_{31,\\text{f}}^{2}/\\varepsilon _{0}\\varepsilon _{\\text{r}}) of the PMN-PT (x = 0.35) thin film reached 21 GPa, which is much higher than that of the other polycrystalline piezoelectric thin films. These results suggest that PMN-PT (x = 0.35) thin film is a promising material for high-efficiency piezoelectric MEMS energy harvesters.

  5. Amino Acid Composition, Urease Activity and Trypsin Inhibitor Activity after Toasting of Soybean in Thick and Thin Layer

    Directory of Open Access Journals (Sweden)

    Tajana Krička

    2009-12-01

    Full Text Available The objective of this study was to determine amino acid content, urease activity and trypsin inhibitor activity in soybean grain for polygastric animals’ feed aft er toasting with the aim to introduce thick layer in toasting technology. Hence, soybean was toasted both in thick and thin layer at 130 oC during 10 minutes. In order to properly monitor the technological process of soybean thermal processing, it was necessary to study crude protein content, urease activity, trypsin inhibitor activity and amino acid composition of soybean in natural and toasted samples. Results demonstrate that protein content in soybean toasted in thick and thin layer was found to be slightly increased while urease activity was reduced in relation to non-treated sample. Study also established a significant reduction of trypsin inhibitor activity aft er toasting, at higher extent in thin layer toasting. Amino acid content of soybean was slightly increased in relation to natural sample, as well as difference between amino acid content in samples toasted in thick and thin layers.

  6. Organic thin film transistors with a SiO2/SiNx/SiO2 composite insulator layer

    Institute of Scientific and Technical Information of China (English)

    Liu Xiang; Liu Hui

    2011-01-01

    We have investigated a SiO2/SiNx/SiO2 composite insulation layer structured gate dielectric for an organic thin film transistor (OTFT) with the purpose of improving the performance of the SiO2 gate insulator.The SiO2/SiNx/SiO2 composite insulation layer was prepared by magnetron sputtering.Compared with the same thickness of a SiO2 insulation layer device,the SiO2/SiNx/SiO2 composite insulation layer is an effective method of fabricating OTFT with improved electric characteristics and decreased leakage current.Electrical parameters such as carrier mobility by field effect measurement have been calculated.The performances of different insulating layer devices have been studied,and the results demonstrate that when the insulation layer thickness increases,the off-state current decreases.

  7. Nitric-phosphoric acid etching effects on the surface chemical composition of CdTe thin film.

    Science.gov (United States)

    Irfan, Irfan; Ding, Huanjun; Xia, Wei; Lin, Hao; Tang, Ching W.; Gao, Yongli

    2009-03-01

    Nitric-phosphoric (NP) acid etching has been regarded as one of the most successful methods for the formation of low resistance back contact with the metal electrode in CdTe based solar cells. We report back surface chemical composition for eight different durations of NP etching of CdTe polycrystalline thin film. We studied the surfaces with x-ray photoemission spectroscopy (XPS), ultraviolet photoemission spectroscopy (UPS), inverse photoemission spectroscopy (IEPS) and atomic force microscopy (AFM). Etching dependence on the back surface composition and electronic structure was observed. Valence and conduction band shifts relative to the Fermi level of the system with different etching duration were analyzed. The sample was left in open ambient condition for three weeks and XPS data were obtained again in order to study the difference in surface chemical composition with the pristine CdTe film. Unetched and highly etched part of the sample were sputtered and the depth profile analyzed.

  8. Mechanical and bending properties of a conductive thin single layer composite consisting of carbon nanofibers and polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol [Kyungpook National University, Daegu (Korea, Republic of); Zhang, Shuai [Ningxia University, Yinchuan (China)

    2014-07-15

    A new conductive composite material with conductive polymer and carbon nanofibers (CNF) was developed to improve some problems such as a slow response and a low actuating force. The disadvantage has been improved in this study by means of using a single layer thin film of PPy (polypyrrole) and conductive composites consisting of CNF and PPy. The composite films were successfully fabricated by the electrophoretic and polymerization method newly developed. The tension tests results show that the strain of CNF/PPy decreases as CNF weight ratio increases. The bending actuation occurs for both pure PPy and CNF/PPy single layer films when an electric current was applied. The tip deflections of the films varied in the range 0.5mm to 2mm. Tension tests were performed with 0%, 3%, 5%, and 7% weight ratios of CNF's. Specimens with a higher CNF ratio showed larger moduli.

  9. Mechanical and dielectric characterization of lead zirconate titanate(PZT)/polyurethane(PU) thin film composite for energy harvesting

    Science.gov (United States)

    Aboubakr, S.; Rguiti, M.; Hajjaji, A.; Eddiai, A.; Courtois, C.; d'Astorg, S.

    2014-04-01

    The Lead Zirconate titanate (PZT) ceramic is known by its piezoelectric feature, but also by its stiffness, the use of a composite based on a polyurethane (PU) matrix charged by a piezoelectric material, enable to generate a large deformation of the material, therefore harvesting more energy. This new material will provide a competitive alternative and low cost manufacturing technology of autonomous systems (smart clothes, car seat, boat sail, flag ...). A thin film of the PZT/PU composite was prepared using up to 80 vol. % of ceramic. Due to the dielectric nature of the PZT, inclusions of this one in a PU matrix raises the permittivity of the composite, on other hand this latter seems to decline at high frequencies.

  10. PZT/P(VDF-HFP) 0-3 composites as solvent-cast thin films: preparation, structure and piezoelectric properties

    Energy Technology Data Exchange (ETDEWEB)

    Wegener, Michael; Arlt, Kristin [Functional Polymer Systems, Fraunhofer Institute for Applied Polymer Research (IAP), Geiselbergstrasse 69, 14476 Potsdam-Golm (Germany)], E-mail: michael.wegener@iap.fraunhofer.de

    2008-08-21

    Composite films of lead zirconate titanate (PZT) and poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) were prepared as 100 {mu}m thin films by solvent casting. Within the 0-3 composites, the ceramic-volume fraction was varied between 0.19 and 0.65, which yielded films with different structural and dielectric properties. These influenced the piezoelectric properties of the composite films found after electric poling, which was performed here at room temperature. The piezoelectric activity, with a maximum piezoelectric coefficient of 11 pC N{sup -1} in the film-thickness direction, originates from the polarization of the embedded ceramic particles as proved by poling experiments in corona discharges as well as in direct contact.

  11. Preparation and dielectric properties of compositionally graded (Ba,Sr)TiO3 thin film by sol-gel technique

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tian-jin; WANG Jun; ZHANG Bai-shun; WANG Jin-zhao; WAN Neng; HU Lan

    2006-01-01

    Compositional graded BaxSr1-xTiO3 (x=0.6,0.7,0.8,0.9,1.0) (BST) thin films (less than 400 nm) were fabricated on Si and Pt/Ti/SiO2/Si substrates by sol-gel technique. A special heating treatment was employed to form the uniform composition gradients at 700 ℃. The microstructures of the films were studied by means of X-ray diffraction,atomic force microscope and field emission scanning electron microscopy. The results show that the films have uniform and crack-free surface morphology with perovskite structure phase. The small signal dielectric constant (εr) and dielectric loss (tanδ) are found to be 335 and 0.045 at room temperature and 200 kHz. The dielectric properties change significantly with applied dc bias,and the graded thin film show high tunability of 42.3% at an applied field of 250 kV/cm. All the results indicate that the graded BST thin films prepared by sol-gel technique have a promising candidate for microelectronic device.

  12. Spray Layer-by-Layer Assembled Clay Composite Thin Films as Selective Layers in Reverse Osmosis Membranes.

    Science.gov (United States)

    Kovacs, Jason R; Liu, Chaoyang; Hammond, Paula T

    2015-06-24

    Spray layer-by-layer assembled thin films containing laponite (LAP) clay exhibit effective salt barrier and water permeability properties when applied as selective layers in reverse osmosis (RO) membranes. Negatively charged LAP platelets were layered with poly(diallyldimethylammonium) (PDAC), poly(allylamine) (PAH), and poly(acrylic acid) (PAA) in bilayer and tetralayer film architectures to generate uniform films on the order of 100 nm thick that bridge a porous poly(ether sulfone) support to form novel RO membranes. Nanostructures were formed of clay layers intercalated in a polymeric matrix that introduced size-exclusion transport mechanisms into the selective layer. Thermal cross-linking of the polymeric matrix was used to increase the mechanical stability of the films and improve salt rejection by constraining swelling during operation. Maximum salt rejection of 89% was observed for the tetralayer film architecture, with an order of magnitude increase in water permeability compared to commercially available TFC-HR membranes. These clay composite thin films could serve as a high-flux alternative to current polymeric RO membranes for wastewater and brackish water treatment as well as potentially for forward osmosis applications. In general, we illustrate that by investigating the composite systems accessed using alternating layer-by-layer assembly in conjunction with complementary covalent cross-linking, it is possible to design thin film membranes with tunable transport properties for water purification applications.

  13. Characterisation of thin films of graphene–surfactant composites produced through a novel semi-automated method

    Directory of Open Access Journals (Sweden)

    Nik J. Walch

    2016-02-01

    Full Text Available In this paper we detail a novel semi-automated method for the production of graphene by sonochemical exfoliation of graphite in the presence of ionic surfactants, e.g., sodium dodecyl sulfate (SDS and cetyltrimethylammonium bromide (CTAB. The formation of individual graphene flakes was confirmed by Raman spectroscopy, while the interaction of graphene with surfactants was proven by NMR spectroscopy. The resulting graphene–surfactant composite material formed a stable suspension in water and some organic solvents, such as chloroform. Graphene thin films were then produced using Langmuir–Blodgett (LB or electrostatic layer-by-layer (LbL deposition techniques. The composition and morphology of the films produced was studied with SEM/EDX and AFM. The best results in terms of adhesion and surface coverage were achieved using LbL deposition of graphene(−SDS alternated with polyethyleneimine (PEI. The optical study of graphene thin films deposited on different substrates was carried out using UV–vis absorption spectroscopy and spectroscopic ellipsometry. A particular focus was on studying graphene layers deposited on gold-coated glass using a method of total internal reflection ellipsometry (TIRE which revealed the enhancement of the surface plasmon resonance in thin gold films by depositing graphene layers.

  14. THE ANALYSIS OF THIN WALLED COMPOSITE LAMINATED HELICOPTER ROTOR WITH HIERARCHICAL WARPING FUNCTIONS AND FINITE ELEMENT METHOD

    Institute of Scientific and Technical Information of China (English)

    诸德超; 邓忠民; 王荇卫

    2001-01-01

    In the present paper, a series of hierarchical warping functions is developed to analyze the static and dynamic problems of thin walled composite laminated helicopter rotors composed of several layers with single closed cell. This ethod is the development and extension of the traditional constrained warping theory of thin walled metallic beams, which had been proved very successful since 1940s. The warping distribution along the perimeter of each layer is expanded into a series of successively corrective warping functions with the traditional warping function caused by free torsion or free bending as the first term, and is assumed to be piecewise linear along the thickness direction of layers. The governing equations are derived based upon the variational principle of minimum potential energy for static analysis and Rayleigh Quotient for free vibration analysis. Then the hierarchical finite element method is introduced to form a numerical algorithm. Both static and natural vibration problems of sample box beams are analyzed with the present method to show the main mechanical behavior of the thin walled composite laminated helicopter rotor.

  15. Atom-Thin SnS2-xSex with Adjustable Compositions by Direct Liquid Exfoliation from Single Crystals.

    Science.gov (United States)

    Yang, Zhanhai; Liang, Hui; Wang, Xusheng; Ma, Xinlei; Zhang, Tao; Yang, Yanlian; Xie, Liming; Chen, Dong; Long, Yujia; Chen, Jitao; Chang, Yunjie; Yan, Chunhua; Zhang, Xinxiang; Zhang, Xueji; Ge, Binghui; Ren, Zhian; Xue, Mianqi; Chen, Genfu

    2016-01-26

    Two-dimensional (2D) chalcogenide materials are fundamentally and technologically fascinating for their suitable band gap energy and carrier type relevant to their adjustable composition, structure, and dimensionality. Here, we demonstrate the exfoliation of single-crystal SnS2-xSex (SSS) with S/Se vacancies into an atom-thin layer by simple sonication in ethanol without additive. The introduction of vacancies at the S/Se site, the conflicting atomic radius of sulfur in selenium layers, and easy incorporation with an ethanol molecule lead to high ion accessibility; therefore, atom-thin SSS flakes can be effectively prepared by exfoliating the single crystal via sonication. The in situ pyrolysis of such materials can further adjust their compositions, representing tunable activation energy, band gap, and also tunable response to analytes of such materials. As the most basic and crucial step of the 2D material field, the successful synthesis of an uncontaminated and atom-thin sample will further push ahead the large-scale applications of 2D materials, including, but not limited to, electronics, sensing, catalysis, and energy storage fields.

  16. Synthesis and surface properties of polyamide-CuxSe composite thin films

    NARCIS (Netherlands)

    Ivanauskas, R.; Baltrusaitis, J.

    2013-01-01

    A study of copper selenide (CuxSe) thin film deposition on PA 6 polymer surface via adsorption/diffusion method and the resulting surface properties is presented. A two stage process used to deposit these thin films involves (a) selenization in 0.1 M K2SeS2O6 at pH 2.15 and 60 °C followed by (b) tre

  17. Thin-Film Composite Pressure Retarded Osmosis Membranes for Sustainable Power Generation from Salinity Gradients

    KAUST Repository

    Yip, Ngai Yin

    2011-05-15

    Pressure retarded osmosis has the potential to produce renewable energy from natural salinity gradients. This work presents the fabrication of thin-film composite membranes customized for high performance in pressure retarded osmosis. We also present the development of a theoretical model to predict the water flux in pressure retarded osmosis, from which we can predict the power density that can be achieved by a membrane. The model is the first to incorporate external concentration polarization, a performance limiting phenomenon that becomes significant for high-performance membranes. The fabricated membranes consist of a selective polyamide layer formed by interfacial polymerization on top of a polysulfone support layer made by phase separation. The highly porous support layer (structural parameter S = 349 μm), which minimizes internal concentration polarization, allows the transport properties of the active layer to be customized to enhance PRO performance. It is shown that a hand-cast membrane that balances permeability and selectivity (A = 5.81 L m-2 h-1 bar-1, B = 0.88 L m-2 h-1) is projected to achieve the highest potential peak power density of 10.0 W/m2 for a river water feed solution and seawater draw solution. The outstanding performance of this membrane is attributed to the high water permeability of the active layer, coupled with a moderate salt permeability and the ability of the support layer to suppress the undesirable accumulation of leaked salt in the porous support. Membranes with greater selectivity (i.e., lower salt permeability, B = 0.16 L m-2 h-1) suffered from a lower water permeability (A = 1.74 L m-2 h-1 bar-1) and would yield a lower peak power density of 6.1 W/m2, while membranes with a higher permeability and lower selectivity (A = 7.55 L m-2 h-1 bar-1, B = 5.45 L m-2 h-1) performed poorly due to severe reverse salt permeation, resulting in a similar projected peak power density of 6.1 W/m2. © 2011 American Chemical Society.

  18. High-flux Thin-film Nanofibrous Composite Ultrafiltration Membranes Containing Cellulose Barrier Layer

    Energy Technology Data Exchange (ETDEWEB)

    Ma, H.; Yoon, K; Rong, L; Mao, Y; Mo, Z; Fang, D; Hollander, Z; Gaiteri, J; Hsiao , B; Chu, B

    2010-01-01

    A novel class of thin-film nanofibrous composite (TFNC) membrane consisting of a cellulose barrier layer, a nanofibrous mid-layer scaffold, and a melt-blown non-woven substrate was successfully fabricated and tested as an ultrafiltration (UF) filter to separate an emulsified oil and water mixture, a model bilge water for on-board ship bilge water purification. Two ionic liquids: 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate, were chosen as the solvent to dissolve cellulose under mild conditions. The regenerated cellulose barrier layer exhibited less crystallinity (determined by wide-angle X-ray diffraction, WAXD) than the original cotton linter pulps, but good thermal stability (determined by thermal gravimetric analysis, TGA). The morphology, water permeation, and mechanical stability of the chosen TFNCmembranes were thoroughly investigated. The results indicated that the polyacrylonitrile (PAN) nanofibrous scaffold was partially imbedded in the cellulose barrier layer, which enhanced the mechanical strength of the top barrier layer. The permeation flux of the cellulose-based TFNCmembrane was significantly higher (e.g. 10x) than comparable commercial UFmembranes (PAN10 and PAN400, Sepro) with similar rejection ratios for separation of oil/water emulsions. The molecular weight cut-off (MWCO) of TFNC membranes with cellulose barrier layer was evaluated using dextran feed solutions. The rejection was found to be higher than 90% with a dextran molecular weight of 2000 KDa, implying that the nominal pore size of the membrane was less than 50 nm. High permeation flux was also observed in the filtration of an emulsified oil/water mixture as well as of a sodium alginate aqueous solution, while high rejection ratio (above 99.5%) was maintained after prolonged operation. A variation of the barrier layer thickness could dramatically affect the permeation flux and the rejection ratio of the TFNCmembranes, while different sources of cellulose

  19. Thermal Vapor Deposition and Characterization of Polymer-Ceramic Nanoparticle Composite Thin Films and Capacitors

    Science.gov (United States)

    Ewen, Crystal L.

    Thin films composed of the polymer polyvinylidene uoride (PVDF) and the ceramic nanoparticle titanium dioxide (TiO2) were fabricated via thermal vapor deposition. The goal of this research was to improve the amount of TiO2 deposited by varying the temperature and deposition time, to obtain more accurate thickness measurements, and to improve on the electrical properties. The electrical properties analyzed in this study were the dielectric constant, capacitance, breakdown strength and energy density of the capacitors. A starting mixture of PVDF, TiO2, and dimethylformamide (DMF) was prepared prior to deposition, where DMF was used only as a solvent. The elemental composition of the films was determined with energy dispersive x-ray spectroscopy (EDS) using a scanning electron microscope (SEM). Elemental mapping of the films shows that the nanoparticles are homogeneously distributed in the polymer. The ideal initial concentrations (which yield the largest TiO2 concentration) of PVDF and TiO2 were determined to be 83% and 17% respectively by weight. The highest weight percent of Ti was 32.4%, which was made with a deposition temperature of 474°C (corresponding to a current of 27 A) and deposition time of 13 minutes. Thefilm thickness was measured by combining EDS and ImageJ to be 243--46 nm. Parallel plate capacitors were fabricated by combining thermal vapor deposition for the dielectric and sputter coating for the electrodes. For the electrodes, the parallel plates are gold palladium (AuPd) with PVDF:TiO2 as the dielectric. The AuPd electrodes were deposited via sputter coating. Each electrode was sputtered for 100s, which yielded a thickness of 33 nm. The dielectric constant was determined experimentally to be 10.8 and estimated using the Maxwell-Garnett effective medium approximation to be 13.1. The capacitance of these capacitors averaged 30--2 nF. The breakdown voltage of the capacitor was 25--4 V, which corresponds to a breakdown strength of 103 MV/m. Lastly

  20. Composition and structure variation for magnetron sputtered tantalum oxynitride thin films, as function of deposition parameters

    Energy Technology Data Exchange (ETDEWEB)

    Cristea, D.; Pătru, M.; Crisan, A.; Munteanu, D. [Department of Materials Science, Transilvania University, 500036 Brasov (Romania); Crăciun, D. [Laser Department, National Institute for Laser, Plasma, and Radiation Physics, Magurele (Romania); Barradas, N.P. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Apreutesei, M. [Université de Lyon, Institut des Nanotechnologies de Lyon INL-UMR 5270, CNRS, Ecole Centrale de Lyon, Ecully F-69134 (France); MATEIS Laboratory-INSA de Lyon, Bât. B. Pascal, 7 Avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Moura, C. [Center of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Cunha, L., E-mail: lcunha@fisica.uminho.pt [Center of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2015-12-15

    Highlights: • Structural evolution from β-Ta, to fcc-Ta(O,N), to amorphous Ta{sub 2}O{sub 5} with increasing P(N{sub 2} + O{sub 2}). • The substrate bias influences the N content, but does not influence the O content of the films. • The structural features of the films appear at lower P(N{sub 2} + O{sub 2}) when produced with grounded substrate. - Abstract: Tantalum oxynitride thin films were produced by magnetron sputtering. The films were deposited using a pure Ta target and a working atmosphere with a constant N{sub 2}/O{sub 2} ratio. The choice of this constant ratio limits the study concerning the influence of each reactive gas, but allows a deeper understanding of the aspects related to the affinity of Ta to the non-metallic elements and it is economically advantageous. This work begins by analysing the data obtained directly from the film deposition stage, followed by the analysis of the morphology, composition and structure. For a better understanding regarding the influence of the deposition parameters, the analyses are presented by using the following criterion: the films were divided into two sets, one of them produced with grounded substrate holder and the other with a polarization of −50 V. Each one of these sets was produced with different partial pressure of the reactive gases P(N{sub 2} + O{sub 2}). All the films exhibited a O/N ratio higher than the N/O ratio in the deposition chamber atmosphere. In the case of the films produced with grounded substrate holder, a strong increase of the O content is observed, associated to the strong decrease of the N content, when P(N{sub 2} + O{sub 2}) is higher than 0.13 Pa. The higher Ta affinity for O strongly influences the structural evolution of the films. Grazing incidence X-ray diffraction showed that the lower partial pressure films were crystalline, while X-ray reflectivity studies found out that the density of the films depended on the deposition conditions: the higher the gas pressure, the

  1. Aluminum-thin-film packaged fiber Bragg grating probes for monitoring the maximum tensile strain of composite materials.

    Science.gov (United States)

    Im, Jooeun; Kim, Mihyun; Choi, Ki-Sun; Hwang, Tae-Kyung; Kwon, Il-Bum

    2014-06-10

    In this paper, new fiber Bragg grating (FBG) sensor probes are designed to intermittently detect the maximum tensile strain of composite materials, so as to evaluate the structural health status. This probe is fabricated by two thin Al films bonded to an FBG optical fiber and two supporting brackets, which are fixed on the surface of composite materials. The residual strain of the Al packaged FBG sensor probe is induced by the strain of composite materials. This residual strain can indicate the maximum strain of composite materials. Two types of sensor probes are prepared-one is an FBG with 18 μm thick Al films, and the other is an FBG with 36 μm thick Al films-to compare the thickness effect on the detection sensitivity. These sensor probes are bonded on the surfaces of carbon fiber reinforced plastics composite specimens. In order to determine the strain sensitivity between the residual strain of the FBG sensor probe and the maximum strain of the composite specimen, tensile tests are performed by universal testing machine, under the loading-unloading test condition. The strain sensitivities of the probes, which have the Al thicknesses of 18 and 36 μm, are determined as 0.13 and 0.23, respectively.

  2. Compositional-induced structural change in Zr{sub x}Ni{sub 100−x} thin film metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Ghidelli, Matteo, E-mail: matteo.ghidelli@simap.grenoble-inp.fr [Science and Engineering of Materials and Processes, SIMaP, Université de Grenoble/CNRS, UJF/Grenoble INP, BP46, 38402 Saint-Martin d’Hères (France); Institute of Mechanics, Materials and Civil Engineering, IMMC, Université catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Institute of Information and Communication Technologies, Electronics and Applied Mathematics, ICTEAM, Université catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Gravier, Sébastien; Blandin, Jean-Jacques [Science and Engineering of Materials and Processes, SIMaP, Université de Grenoble/CNRS, UJF/Grenoble INP, BP46, 38402 Saint-Martin d’Hères (France); Pardoen, Thomas [Institute of Mechanics, Materials and Civil Engineering, IMMC, Université catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Raskin, Jean-Pierre [Institute of Information and Communication Technologies, Electronics and Applied Mathematics, ICTEAM, Université catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Mompiou, Frédéric [CEMES-CNRS, Université de Toulouse, 29, rue J. Marvig, 31005 Toulouse (France)

    2014-12-05

    Highlights: • A composite ZrNi target is used to accurately tune ZrNi thin film composition. • The atomic structure of metallic glass films is determined for several compositions. • Short and medium range order is inferred for amorphous compositions. • Crystallization phenomena are detected for Zr-rich specimens. • Crystallization is justified on the basis Nagel and Tauc criterion. - Abstract: The structure of Zr{sub x}Ni{sub 100−x} thin film metallic glasses (TFMGs) has been studied for a variety of compositions obtained by DC magnetron sputtering using a composite ZrNi target. The crystallization has been characterized by X-ray diffraction and transmission electron microscopy revealing also short and medium range order for amorphous compositions. The TFMGs thermodynamic stability has been evaluated by exploiting the Nagel and Tauc criterion, justifying the occurrence of crystallization in the Zr-rich specimens.

  3. Lignocellulose-derived thin stillage composition and efficient biological treatment with a high-rate hybrid anaerobic bioreactor system

    KAUST Repository

    Oosterkamp, Margreet J.

    2016-06-06

    Background This study aims to chemically characterize thin stillage derived from lignocellulosic biomass distillation residues in terms of organic strength, nutrient, and mineral content. The feasibility of performing anaerobic digestion on these stillages at mesophilic (40 °C) and thermophilic (55 °C) temperatures to produce methane was demonstrated. The microbial communities involved were further characterized. Results Energy and sugar cane stillage have a high chemical oxygen demand (COD of 43 and 30 g/L, respectively) and low pH (pH 4.3). Furthermore, the acetate concentration in sugar cane stillage was high (45 mM) but was not detected in energy cane stillage. There was also a high amount of lactate in both types of stillage (35–37 mM). The amount of sugars was 200 times higher in energy cane stillage compared to sugar cane stillage. Although there was a high concentration of sulfate (18 and 23 mM in sugar and energy cane stillage, respectively), both thin stillages were efficiently digested anaerobically with high COD removal under mesophilic and thermophilic temperature conditions and with an organic loading rate of 15–21 g COD/L/d. The methane production rate was 0.2 L/g COD, with a methane percentage of 60 and 64, and 92 and 94 % soluble COD removed, respectively, by the mesophilic and thermophilic reactors. Although both treatment processes were equally efficient, there were different microbial communities involved possibly arising from the differences in the composition of energy cane and sugar cane stillage. There was more acetic acid in sugar cane stillage which may have promoted the occurrence of aceticlastic methanogens to perform a direct conversion of acetate to methane in reactors treating sugar cane stillage. Conclusions Results showed that thin stillage contains easily degradable compounds suitable for anaerobic digestion and that hybrid reactors can efficiently convert thin stillage to methane under mesophilic and thermophilic conditions

  4. Compositional study of vacuum annealed Al doped ZnO thin films obtained by RF magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Shantheyanda, B. P.; Todi, V. O.; Sundaram, K. B.; Vijayakumar, A.; Oladeji, I. [Department of Electrical Engineering and Computer Science, University of Central Florida, Orlando, Florida 32816 (United States); Planar Energy Inc., 653 W. Michigan St., Orlando, Florida 32805 (United States)

    2011-09-15

    Aluminum doped zinc oxide (AZO) thin films were obtained by RF magnetron sputtering. The effects of deposition parameters such as power, gas flow conditions, and substrate heating have been studied. Deposited and annealed films were characterized for composition as well as microstructure using x ray photoelectron spectroscopy and x ray diffraction. Films produced were polycrystalline in nature. Surface imaging and roughness studies were carried out using SEM and AFM, respectively. Columnar grain growth was predominantly observed. Optical and electrical properties were evaluated for transparent conducting oxide applications. Processing conditions were optimized to obtain highly transparent AZO films with a low resistivity value of 6.67 x 10{sup -4}{Omega} cm.

  5. CRADA Final Report: Properties of Vacuum Deposited Thin Films of Lithium Phosphorous Oxynitride (Lipon) with an Expanded Composition Range

    Energy Technology Data Exchange (ETDEWEB)

    Dudney, N.J.

    2003-12-29

    Thin films of an amorphous, solid-state, lithium electrolyte, referred to as ''Lipon'', were first synthesized and characterized at ORNL in 1991. This material is typically prepared by magnetron sputtering in a nitrogen plasma, which allows nitrogen atoms to substitute for part of the oxygen ions of Li{sub 3}PO{sub 4}. Lipon is the key component in the successful fabrication of ORNL's rechargeable thin film microbatteries. Cymbet and several other US Companies have licensed this technology for commercialization. Optimizing the properties of the Lipon material, particularly the lithium ion conductivity, is extremely important, yet only a limited range of compositions had been explored prior to this program. The goal of this CRADA was to develop new methods to prepare Lipon over an extended composition range and to determine if the film properties might be significantly improved beyond those previously reported by incorporating a larger N component into the film. Cymbet and ORNL investigated different deposition processes for the Lipon thin films. Cymbet's advanced deposition process not only achieved a higher deposition rate, but also permitted independent control the O and N flux to the surface of the growing film. ORNL experimented with several modified sputtering techniques and found that by using sectored sputter targets, composed of Li{sub 3}PO{sub 4} and Li{sub 3}N ceramic disks, thin Lipon films could be produced over an expanded composition range. The resulting Lipon films were characterized by electrical impedance, infrared spectroscopy, and several complementary analytical techniques to determine the composition. When additional N plus Li are incorporated into the Lipon film, the lithium conductivity was generally degraded. However, the addition of N accompanied by a slight loss of Li gave an increase in the conductivity. Although the improvement in the conductivity was only very modest and was a disappointing conclusion of

  6. Ferrimagnetic Tb-Fe Alloy Thin Films: Composition and Thickness Dependence of Magnetic Properties and All-Optical Switching

    Directory of Open Access Journals (Sweden)

    Birgit eHebler

    2016-02-01

    Full Text Available Ferrimagnetic rare earth - transition metal Tb-Fe alloy thin films exhibit a variety of different magnetic properties, which depends strongly on composition and temperature. In this study, first the influence of the film thickness (5 - 85 nm on the sample magnetic properties was investigated in a wide composition range between 15 at.% and 38 at.% of Tb. From our results, we find that the compensation point, remanent magnetization, and magnetic anisotropy of the Tb-Fe films depend not only on the composition but also on the thickness of the magnetic film up to a critical thickness of about 20-30 nm. Beyond this critical thickness, only slight changes in magnetic properties are observed. This behavior can be attributed to a growth-induced modification of the microstructure of the amorphous films, which affects the short range order. As a result, a more collinear alignment of the distributed magnetic moments of Tb along the out-of-plane direction with film thickness is obtained. This increasing contribution of the Tb sublattice magnetization to the total sample magnetization is equivalent to a sample becoming richer in Tb and can be referred to as an effective composition. Furthermore, the possibility of all-optical switching, where the magnetization orientation of Tb-Fe can be reversed solely by circularly polarized laser pulses, was analyzed for a broad range of compositions and film thicknesses and correlated to the underlying magnetic properties.

  7. Conductive ZnO:Zn Composites for High-Rate Sputtering Deposition of ZnO Thin Films

    Science.gov (United States)

    Zhou, Li Qin; Dubey, Mukul; Simões, Raul; Fan, Qi Hua; Neto, Victor

    2015-02-01

    We report an electrically conductive composite prepared by sintering ZnO and metallic Zn powders. Microstructure analysis combined with electrical conductivity studies indicated that when the proportion of metallic Zn reached a threshold (˜20 wt.%), a metal matrix was formed in accordance with percolation theory. This composite has potential as a sputtering target for deposition of high-quality ZnO. Use of the ZnO:Zn composite completely eliminates target poisoning effects in reactive sputtering of the metal, and enables deposition of thin ZnO films at rates much higher than those obtained by sputtering of pure ZnO ceramic targets. The optical transmittance of the ZnO films prepared by use of this composite is comparable with that of films produced by radio frequency sputtering of pure ZnO ceramic targets. The sputtering characteristics of the conductive ZnO:Zn composite target are reported, and possible mechanisms of the high rate of deposition are also discussed.

  8. Correlation between composition, morphology and optical properties of PVK: n-ZnO:CTAB thin films

    Science.gov (United States)

    Azizi, Samir; Belhaj, Marwa; Zargouni, Sarra; Dridi, Cherif

    2017-07-01

    In this study, we report on the effect of zinc oxide nanoparticles ( n-ZnO) content and surfactant addition on the performance of poly ( N-vinylcarbazole) (PVK): n-ZnO nanocomposite thin films. Morphological and optical properties of ZnO, PVK and PVK: n-ZnO:cetyltrimethyl ammonium bromide (CTAB) hybrid films were investigated by atomic force microscopy (AFM), UV-Visible spectrophotometry and photoluminescence (PL) spectroscopy. We noticed that surface morphology was very dependent on surfactant addition into inorganic and organic components and on the ZnO content in the mixture. The optical absorption spectra of PVK: n-ZnO thin films showed a red shift of the optical band gap energy. Besides, PL measurements demonstrated an interfacial charge transfer between PVK matrix and ZnO nanoparticles through the reduced PL intensity of nanocomposites compared to PVK thin films.

  9. Composition influence on the microstructures and magnetic properties of FePt thin films

    Institute of Scientific and Technical Information of China (English)

    Liu Li-Wang; Dang Hong-Gang; Sheng Wei; Wang Ying; Cao Jiang-Wei; Bai Jian-Min; Wei Fu-Lin

    2013-01-01

    The FexPt100-x (10 nm) (x =31-51) thin films are fabricated on Si (100) substrates by using magnetron sputtering.The highly ordered L10 FePt phase is obtained after post-annealing at 700 ℃C in Fe47Pt53 thin film.The sample shows good perpendicular anisotropy with a square loop and a linear loop in the out-of-plane and the in-plane direction,respectively.The variations of the magnetic domains are investigated in the films when the content value of Fe changes from 31% to 51%.

  10. Smart three-dimensional lightweight structure triggered from a thin composite sheet via 3D printing technique.

    Science.gov (United States)

    Zhang, Quan; Zhang, Kai; Hu, Gengkai

    2016-02-29

    Complex fabrication process and expensive materials have restricted the development of smart three-dimensional (3D) lightweight structures, which are expected to possess self-shaping, self-folding and self-unfolding performances. Here we present a simple approach to fabricate smart lightweight structures by triggering shape transformation from thin printed composite sheets. The release of the internal strain in printed polymer materials enables the printed composite sheet to keep flat under heating and transform into a designed 3D configuration when cooled down to room temperature. The 3D lightweight structure can be switched between flat and 3D configuration under appropriate thermal stimuli. Our work exploits uniform internal strain in printed materials as a controllable tool to fabricate smart 3D lightweight structures, opening an avenue for possible applications in engineering fields.

  11. Effects of Mineral Tourmaline Particles on Photocatalytic Activities of RE/TiO2 Composite Thin Films

    Institute of Scientific and Technical Information of China (English)

    Meng Junping; Liang Jinsheng; Ding Yan; Xu Gangke

    2004-01-01

    The composite TiO2 films containing the mineral tourmaline particles and rare earth elements (T/RE/TiO2 )were prepared by a sol-gel method using Ti( OC4H9 )4 as raw material. The microstructure and forming mechanism of T/RE/TiO2 films were studied by scanning electron microscope (SEM). Effects of tourmaline on the photocatalytic activities of RE/TiO2 were determined by photocatalytic degradation of formaldehyde. The results show that the photocatalytic degradation ratio of formaldehyde increases by 44.2% with the composite films of Ce/TiO2 containing 0.04%tourmaline, more than that with the thin films of Ce/TiO2 under UV irradiation.

  12. Preparation of thin film nanofibrous composite NF membrane based on EDC/NHS modified PAN-AA nanofibrous substrate

    Science.gov (United States)

    Yang, Y.; Wang, X.; Hsiao, B. S.

    2016-07-01

    A novel kind of thin-film nanofibrous composite (TFNC) nanofiltration (NF) membranes consisting of a polyamide (PA) barrier layer were successfully fabricated by interfacial polymerization (IFP) based on electrospun double-layer nanofibrous substrates, which have an ultrathin poly (acrylonitrile-co-acrylic acid) (PAN-AA) nanofibrous layer as top layer and a thicker polyacrylonitrile (PAN) nanofiber layer as bottom porous support layer. Immersing PAN/PAN-AA nanofibrous substrates into 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) aqueous solution and piperazine (PIP) aqueous solution (0.20 wt%) sequentially for a period of time, the carboxyl groups on PAN-AA nanofibers were activated by carbodiimide and then reacted with the amide groups. The as prepared composite membrane has an integrated structure with high rejection rate (98.0%); high permeate flux (40.4 L/m2h) for MgSO4 aqueous solution (2 g/L).

  13. Synthesis and characterization of polyester thin film composite membrane via interfacial polymerization: Fouling behaviour of uncharged solute

    Science.gov (United States)

    Mah, K. H.; Yussof, H. W.; Seman, M. N. A.; Mohammad, A. W.

    2016-11-01

    Most hydrolysis studies on biomass in Malaysia produce high amount of xylose and glucose compared to other monosaccharides and most of them are acidic. Thin film composite (TFC) membrane developed via interfacial polymerization using triethanolamine (TEOA) and trimesoyl chloride (TMC) as monomers allows separation at low pH to occur without damaging its performance. Comparative studies were carried out on membranes with and without the thin film layer formed via interfacial polymerization on the polyethersulfone (PES) support. The surfaces of the membranes were characterized by field emission scanning electronic microscopy (FESEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and hydrophilicity via contact angle measurement. In addition, the performance and uncharged solute fouling behaviour of TFC membrane were also investigated. The TFC membrane used for characterization purposes was prepared at TEOA concentration of 4 % w/v in 1 × 10-6 M sodium hydroxide solution, TMC concentration of 0.25 % w/v in pure hexane, reaction time of 45 minutes, and cured at temperature of 60 °C. Characterization results showed a huge different between the synthesized TFC membrane and the un-synthesized PES membrane in term of surface properties and morphology. Nanofiltration results indicate that the formation of thin layer on top of PES support membrane improved the separation performance compared to PES support membrane. The synthesised polyester TFC membrane have irreversible fouling of 11.02 (±5.60) % and reversible fouling of 5.59 % using water as cleaning agent.

  14. The effect of composition on structural and electronic properties in polycrystalline CuGaSe2 thin film

    Institute of Scientific and Technical Information of China (English)

    Zhang Li; He Qing; Xu Chuan-Ming; Xue Yu-Ming; Li Chang-Jian; Sun Yun

    2008-01-01

    Polycrystalline CuGaSe2 thin films on Mo-coated soda-lime glass substrates have been synthesized by co-evaporation process from Cu, Ga and Se sources. Structural and electrical properties of the as-grown CuGaSe2 films strongly depend on the film composition. Stoichiometric CuGaSe2 is fabricated, as indicated by x-ray diffraction spec-troscope (XRD) and x-ray fluorescence (XRF). A two-phase region is composed of CuGaSe2 and Cu2-xSe phases for Cu-rich films, and CuGaSe2 and CuGa3Se5 phases for Ga-rich films, respectively. Morphological properties are de-tected by scanning electron microscope (SEM) for various compositional films, the grain sizes of the CuGaSe2films decrease with the extent of deviation from stoichiometric composition. Raman spectroscopy of Cu-rich samples shows that there exist large Cu-Se particles on the film surface. The results from Hall effect measurements for typical samples indicate that CuGaSe2 films are always of p-type semiconductor from Cu-rich to Ga-rich. Stoichiometric CuGaSe2 films exhibit relatively large mobility than any other compositional films. Finally, polycrystalline CuGaSe2 thin film solar cell with a best conversion efficiency of 6.02% has been achieved under the standard air mass (AM)1.5 spectrum for 100 mW/cm2 at room temperature (aperture area, 0.24cm2). The open circuit voltage of the CuGaSe2 solar cells is close to770 mV.

  15. Organo-layered double hydroxides composite thin films deposited by laser techniques

    Energy Technology Data Exchange (ETDEWEB)

    Birjega, R. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 77125 Bucharest-Magurele (Romania); Vlad, A., E-mail: angela.vlad@gmail.com [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 77125 Bucharest-Magurele (Romania); Matei, A.; Dumitru, M.; Stokker-Cheregi, F.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, 409 Atomistilor Str., 77125 Bucharest-Magurele (Romania); Zavoianu, R. [University of Bucharest, Faculty of Chemistry, Department of Chemical Technology and Catalysis, 4-12 Regina Elisabeta Bd., Bucharest 030018 (Romania); Raditoiu, V.; Corobea, M.C. [National R.& D. Institute for Chemistry and Petrochemistry, ICECHIM, 202 Splaiul Independentei Str., CP-35-274, 060021 Bucharest (Romania)

    2016-06-30

    Highlights: • PLD and MAPLE was successfully used to produce organo-layered double hydroxides. • The organic anions (dodecyl sulfate-DS) were intercalated in co-precipitation step. • Zn2.5Al-LDH (Zn/Al = 2.5) and Zn2.5Al-DS thin films obtained in this work could be suitable for further applications as hydrophobic surfaces. - Abstract: We used laser techniques to create hydrophobic thin films of layered double hydroxides (LDHs) and organo-modified LDHs. A LDH based on Zn-Al with Zn{sup 2+}/Al{sup 3+} ratio of 2.5 was used as host material, while dodecyl sulfate (DS), which is an organic surfactant, acted as guest material. Pulsed laser deposition (PLD) and matrix assisted pulsed laser evaporation (MAPLE) were employed for the growth of the films. The organic anions were intercalated in co-precipitation step. The powders were subsequently used either as materials for MAPLE, or they were pressed and used as targets for PLD. The surface topography of the thin films was investigated by atomic force microscopy (AFM), the crystallographic structure of the powders and films was checked by X-ray diffraction. FTIR spectroscopy was used to evidence DS interlayer intercalation, both for powders and the derived films. Contact angle measurements were performed in order to establish the wettability properties of the as-prepared thin films, in view of functionalization applications as hydrophobic surfaces, owing to the effect of DS intercalation.

  16. Residual stress in Ta2O5-SiO2 composite thin-film rugate filters prepared by radio frequency ion-beam sputtering.

    Science.gov (United States)

    Tang, Chien-Jen; Jaing, Cheng-Chung; Lee, Kuan-Shiang; Lee, Cheng-Chung

    2008-05-01

    Ta-Si oxide composite thin-film rugate filters were prepared by radio frequency ion-beam sputtering and their residual stress and substrate deflections were measured. The residual stress and substrate deflection of these composite film rugate filters were less than that of notch filters made from a series of discrete quarter-wave layers with alternate high and low indices because of the smooth modulation of composition and no interface structure of the rugate filter.

  17. Synthesis and Properties of High Strength Thin Film Composites of Poly(ethylene Oxide) and PEO-PMMA Blend with Cetylpyridinium Chloride Modified Clay

    OpenAIRE

    Mohammad Saleem Khan; Sabiha Sultana

    2015-01-01

    Ion-conducting thin film composites of polymer electrolytes were prepared by mixing high MW poly(ethylene oxide) (PEO), poly(methyl methacrylate) (PMMA) as a polymer matrix, cetylpyridinium chloride (CPC) modified MMT as filler, and different content of LiClO4 by using solution cast method. The crystallinity, ionic conductivity (σ), and mechanical properties of the composite electrolytes and blend composites were evaluated by using XRD, AC impedance, and UTM studies, respectively. The modific...

  18. Secondary phases and their influence on the composition of the kesterite phase in CZTS and CZTSe thin films.

    Science.gov (United States)

    Just, Justus; Sutter-Fella, Carolin M; Lützenkirchen-Hecht, Dirk; Frahm, Ronald; Schorr, Susan; Unold, Thomas

    2016-06-21

    Secondary phases zinc sulfide/selenide and copper sulfide in Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) thin film samples are investigated by X-ray absorption near edge structure (XANES) analysis at the chalcogen K-edges. Because of the formation of secondary phases the composition of the kesterite phase can deviate significantly from the total sample composition. For a large set of non-stoichiometric samples we find that the cation ratios of the kesterite phase never exceed Zn/Sn = 1 even for Zn-rich CZTS and CZTSe, with all excess Zn being contained in secondary phases. For CZTS the cation ratios are found to be additionally constrained by Cu/Sn ≤ 2, which means that Cu-excess always leads to the formation of CuxS secondary phases. These results give clear bounds on the Cu-rich and Zn-rich sides of the single phase region in polycrystalline CZTS/Se thin films.

  19. Correlating the Local Defect-Level Density with the Macroscopic Composition and Energetics of Chalcopyrite Thin-Film Surfaces.

    Science.gov (United States)

    Bröker, Sebastian; Kück, Dennis; Timmer, Alexander; Lauermann, Iver; Ümsür, Bünyamin; Greiner, Dieter; Kaufmann, Christian A; Mönig, Harry

    2015-06-17

    The unusual defect chemistry of polycrystalline Cu(In,Ga)Se2 (CIGSe) thin films is a main issue for a profound understanding of recombination losses in chalcopyrite thin-film solar cells. Especially, impurity-driven passivation of electronic levels due to point defects segregating at the surface and at grain boundaries is extensively debated. By combining current imaging tunneling spectroscopy with photoelectron spectroscopy, the local defect-level density and unusual optoelectronic grain-boundary properties of this material are correlated with the macroscopic energy levels and surface composition. Vacuum annealing of different CIGSe materials provides evidence that Na diffusion from the glass substrate does not affect the surface defect passivation or grain-boundary properties of standard Cu-poor materials. Furthermore, we find no major impact on the observed thermally activated dipole compensation or the accompanying change in surface band bending (up to 0.6 eV) due to Na. In contrast, Cu-rich CIGSe shows an opposing surface defect chemistry with only minor heat-induced band bending. Our results lead to a comprehensive picture, where the highly desirable type inversion at the p/n interface in standard chalcopyrite thin-film solar cells is dominated by band bending within the CIGSe absorber rather than the result of Na impurities or an n-type defect phase segregating at the interface. This is in accordance with recent studies suggesting a surface reconstruction as the origin for Cu depletion and band-gap widening at the surface of chalcopyrite thin films.

  20. Novel THTBN/MWNTs-OH polyurethane conducting composite thin films for applications in detection of volatile organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Feng, E-mail: fengxu@snnu.edu.cn; Guo, Shuang; Luo, Yan-Ling, E-mail: luoyanl@snnu.edu.cn

    2014-05-01

    Novel polyurethane (PU) conducting composite thin films based on tetrahydroxyl-terminated poly(butadiene-co-acrylonitrile) (THTBN) and hydroxyl-functionalized multi-walled carbon nanotubes (MWNTs-OH), were prepared via an in-situ coupling reaction route between hydroxyl groups and isocyanate groups. The chemical and crystal structures were characterized by Fourier transform infrared spectra (FTIR) and X-ray diffraction (XRD). The morphologies and the dispersion behavior of THTBN/MWNTs-OH were examined by scanning electron microscope (SEM), transmission electron microscopy (TEM) and UV–Vis measurements. The influence of MWNTs-OH loading amount on conducting properties and response to some volatile organic compounds (VOCs) especially benzene and toluene was investigated. The experimental results indicated that MWNTs-OH was tightly encapsulated by PU moieties and homogeneously dispersed in the PU moieties. The as-prepared THTBN/MWNTs-OH PU conducting thin films exhibited strong and selective response to nonpolar benzene and toluene vapors, and the response depends on the loading of MWNTs-OH and VOC vapor concentrations. The improvement in dispersity and sensing properties were closely correlated with the chemical linkage of MWNTs-OH in the THTBN matrices through bridging molecules HDI. The developed PU conducting thin films had fast response and reversibility, significant reproducibility and long-term stability. Therefore, they had a possibility as a candidate of volatile organic solvent vapor sensors. - Highlights: • Novel THTBN/MWNTs-OH PU films were prepared via in-situ coupling reaction. • The structure, morphology and dispersion behavior were examined. • The films displayed good response, selectivity, reversibility and stability. • The response depended upon the loading of MWNTs-OH and vapor concentrations. • The composite films can be used as sensors to detect benzene and toluene vapors.

  1. Highly transparent low resistance ZnO/Ag nanowire/ZnO composite electrode for thin film solar cells.

    Science.gov (United States)

    Kim, Areum; Won, Yulim; Woo, Kyoohee; Kim, Chul-Hong; Moon, Jooho

    2013-02-26

    We present an indium-free transparent conducting composite electrode composed of silver nanowires (AgNWs) and ZnO bilayers. The AgNWs form a random percolating network embedded between the ZnO layers. The unique structural features of our ZnO/AgNW/ZnO multilayered composite allow for a novel transparent conducting electrode with unprecedented excellent thermal stability (∼375 °C), adhesiveness, and flexibility as well as high electrical conductivity (∼8.0 Ω/sq) and good optical transparency (>91% at 550 nm). Cu(In,Ga)(S,Se)₂ (CIGSSe) thin film solar cells incorporating this composite electrode exhibited a 20% increase of the power conversion efficiency compared to a conventional sputtered indium tin oxide-based CIGSSe solar cell. The ZnO/AgNW/ZnO composite structure enables effective light transmission and current collection as well as a reduced leakage current, all of which lead to better cell performance.

  2. Evaluation of SOCl2 doping effect on electrical conductivity of thin films of SWNTs and SWNT/PEDOT-PSS composites.

    Science.gov (United States)

    Najeeb, Choolakadavil Khalid; Lee, Jae-Hyeok; Chang, Jingbo; Kim, Jae-Ho

    2011-07-01

    Transparent conductive thin films of single-walled carbon nanotubes (SWNTs) and their nanocomposites with an organic conductive polymer, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) with different CNT loadings ranging from 20 to 90 wt% were prepared and doped by exposing them to thionyl chloride (SOCl2) vapors. After exposure to SOCl2 vapor for 1 h, the SWNT film showed about 15-18% increase of electrical conductivity, while on the other hand pristine polymer film showed a decrease of electrical conductivity. The SWNT-polymer composite films showed a drastic increase in conductivity by doping with SOCl2 vapor, most interestingly, the doping effect was much higher for composite films with less CNT weight fraction and it was linearly decreased with increasing CNT loading. For instance, composite film with 10% and 90% CNT loading demonstrated about 65% and 10% increase of electrical conductivity, respectively. The interaction of SOCl2 vapors on SWNTs and composite films is investigated by UV-visible absorption and Raman spectroscopy.

  3. Microstructure and optical dispersion characterization of nanocomposite sol-gel TiO₂-SiO₂ thin films with different compositions.

    Science.gov (United States)

    Kermadi, S; Agoudjil, N; Sali, S; Zougar, L; Boumaour, M; Broch, L; En Naciri, A; Placido, F

    2015-06-15

    Nanocomposite TiO2-SiO2 thin films with different compositions (from 0 to 100 mol% TiO2) were deposited by sol-gel dip-coating method on silicon substrate. Crystal structure, chemical bonding configuration, composition and morphology evolutions with composition were followed by Raman scattering, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy respectively. The refractive index and the extinction coefficient were derived in a broad band wavelength (250-900 nm) from spectroscopic ellipsometry data with high accuracy and correlated with composition and microstructure. Results showed an anatase structure for 100% TiO2 with a grain size in 6-10nm range. Whereas, the inclusion of SiO2 enlarges the optical band gap and suppresses the grain growth up to 4 nm in size. High TiO2 dispersion in SiO2 matrix was observed for all mixed materials. The refractive index (at λ=600 nm) increases linearly with composition from 1.48 (in 100% SiO2) to 2.22 (in 100% TiO2) leading to lower dense material, its dispersion being discussed in terms of the Wemple-DiDomenico single oscillator model. Hence, the optical parameters, such optical dispersion energies E0 and Ed, the average oscillators, strength S0 and wavelength λ0 and the ratio of the carrier concentration to the effective mass N/m(∗) have been derived. The analysis revealed a strong dependence on composition and structure. The optical response was also investigated in term of complex optical conductivity (σ) and both volume and surface energy loss functions (VELF and SELF).

  4. Metal/Diamond Composite Thin-Film Electrodes: New Carbon Supported Catalytic Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Greg M. Swain, PI

    2009-03-10

    The DOE-funded research conducted by the Swain group was focused on (i) understanding structure-function relationships at boron-doped diamond thin-film electrodes, (ii) understanding metal phase formation on diamond thin films and developing electrochemical approaches for producing highly dispersed electrocatalyst particles (e.g., Pt) of small nominal particle size, (iii) studying the electrochemical activity of the electrocatalytic electrodes for hydrogen oxidation and oxygen reduction and (iv) conducting the initial synthesis of high surface area diamond powders and evaluating their electrical and electrochemical properties when mixed with a Teflon binder. (Note: All potentials are reported versus Ag/AgCl (sat'd KCl) and cm{sup 2} refers to the electrode geometric area, unless otherwise stated).

  5. Control of Dynamic Response of Thin-Walled Composite Beams using Structural Tailoring and Piezoelectric Actuation

    OpenAIRE

    Na, Sungsoo

    1997-01-01

    A dual approach integrating structural tailoring and adaptive materials technology and designed to control the dynamic response of cantilever beams subjected to external excitations is addressed. The cantilevered structure is modeled as a thin-walled beam of arbitrary cross-section and incorporates a number of non-classical effects such as transverse shear, warping restraint, anisotropy of constituent materials and heterogeneity of the construction. Whereas structura...

  6. Organo-layered double hydroxides composite thin films deposited by laser techniques

    Science.gov (United States)

    Birjega, R.; Vlad, A.; Matei, A.; Dumitru, M.; Stokker-Cheregi, F.; Dinescu, M.; Zavoianu, R.; Raditoiu, V.; Corobea, M. C.

    2016-06-01

    We used laser techniques to create hydrophobic thin films of layered double hydroxides (LDHs) and organo-modified LDHs. A LDH based on Zn-Al with Zn2+/Al3+ ratio of 2.5 was used as host material, while dodecyl sulfate (DS), which is an organic surfactant, acted as guest material. Pulsed laser deposition (PLD) and matrix assisted pulsed laser evaporation (MAPLE) were employed for the growth of the films. The organic anions were intercalated in co-precipitation step. The powders were subsequently used either as materials for MAPLE, or they were pressed and used as targets for PLD. The surface topography of the thin films was investigated by atomic force microscopy (AFM), the crystallographic structure of the powders and films was checked by X-ray diffraction. FTIR spectroscopy was used to evidence DS interlayer intercalation, both for powders and the derived films. Contact angle measurements were performed in order to establish the wettability properties of the as-prepared thin films, in view of functionalization applications as hydrophobic surfaces, owing to the effect of DS intercalation.

  7. 在LaNiO3-Pt复合电极上Pb(Zr,Ti)O3铁电薄膜及其成分梯度薄膜的制备和研究%Preparation and Study on Pb(Zr,Ti)O3 Ferroelectric Thin Films and Compositionally Graded Thin Films on LaNiO3-Pt Composite Electrode

    Institute of Scientific and Technical Information of China (English)

    李建康; 姚熹

    2005-01-01

    LaNiO3 (LNO) thin films were prepared on Pt(111)/Ti/SiO2/Si substrate by metal-organic decomposition (MOD) method. Pb(Zr,Ti)O3 ferroelectric thin films and their compositionally graded thin films were prepared on LNO/Pt/Ti/SiO2/Si substrates by Sol-gel method. The composition depth profile of a typical up-graded film was determined by using a combination of Auger Electron Spectroscopy (ASE) and Ar Ion Etching. The results confirm that the processing method produces graded composition changes. XRD analysis showed that the graded thin films possessed composite structure of tetragonal and rhombohedral. The dielectric constants of Up-graded and Down-graded thin films were higher than that of each thin film unit. The dielectric constants were 277 and 269 at 10kHz, respectively. The loss tangents were 0.019 and 0.018 at 10kHz, respectively. The Hysteresis loops showed that the remanent polarizations of graded thin films were higher than that of each thin film unit, but the coercive fields were smaller. The remanent polarizations of Up-graded and Down-graded thin films were 30.06 and 26.96μC·cm-2, respectively. The coercive fields were 54.14, 54.23kV·cm-1, respectively. The pyroelectric coefficients of Up-graded and Down-graded thin films were 4.62, 2.51×10-8 C·cm-2·K-1 at room temperature, respectively. They were higher than that of each thin film unit.

  8. Composition and crystalline properties of TiNi thin films prepared by pulsed laser deposition under vacuum and in ambient Ar gas.

    Science.gov (United States)

    Cha, Jeong Ok; Nam, Tae Hyun; Alghusun, Mohammad; Ahn, Jeung Sun

    2012-01-05

    TiNi shape memory alloy thin films were deposited using the pulsed laser deposition under vacuum and in an ambient Ar gas. Our main purpose is to investigate the influences of ambient Ar gas on the composition and the crystallization temperature of TiNi thin films. The deposited films were characterized by energy-dispersive X-ray spectrometry, a surface profiler, and X-ray diffraction at room temperature. In the case of TiNi thin films deposited in an ambient Ar gas, the compositions of the films were found to be very close to the composition of target when the substrate was placed at the shock front. The in-situ crystallization temperature (ca. 400°C) of the TiNi film prepared at the shock front in an ambient Ar gas was found to be lowered by ca. 100°C in comparison with that of a TiNi film prepared under vacuum.

  9. Low frequency ultrasonic multi-mode Lamb wave method for characterizing the ultra-thin transversely isotropic laminate composite: Theory and experiment

    Institute of Scientific and Technical Information of China (English)

    ZHANG Rui; WAN Mingxi; CHEN Xiao; CAO Wenwu

    2001-01-01

    A low-frequency multi-mode ultrasonic Lamb wave method suitable for characterizing the thickness, the density and the elastic constants of the ultra-thin transversely isotropic laminate composite is presented, The "ultra-thin" here means that the thickness of the plate is much less than the wavelength of the ultrasonic wave so that the echoes from the front and back faces of the plate can't be separated in the time domain. The dispersion equations for the low frequency ultrasonic Lamb waves with the propagation directions parallel and vertical to the fiber direction are derived. In conjunction with the least square algorithm method, the secant algorithm is used to estimate the parameters of the ultra-thin fiber-reinforced composite layer. The evaluation errors and the sensitivity of the method to different parameters of the thin composite are analyzed. The technique has been used to characterize the ultra-thin grass fiber reinforced PES composite with thickness down to ten percents of the ultrasonic wavelength. It is observed that the agreement between the nominal and the estimation values is reasonably good.

  10. Composition of corn dry-grind ethanol by-products: DDGS, wet cake, and thin stillage.

    Science.gov (United States)

    Kim, Youngmi; Mosier, Nathan S; Hendrickson, Rick; Ezeji, Thaddeus; Blaschek, Hans; Dien, Bruce; Cotta, Michael; Dale, Bruce; Ladisch, Michael R

    2008-08-01

    DDGS and wet distillers' grains are the major co-products of the dry grind ethanol facilities. As they are mainly used as animal feed, a typical compositional analysis of the DDGS and wet distillers' grains mainly focuses on defining the feedstock's nutritional characteristics. With an increasing demand for fuel ethanol, the DDGS and wet distillers' grains are viewed as a potential bridge feedstock for ethanol production from other cellulosic biomass. The introduction of DDGS or wet distillers' grains as an additional feed to the existing dry grind plants for increased ethanol yield requires a different approach to the compositional analysis of the material. Rather than focusing on its nutritional value, this new approach aims at determining more detailed chemical composition, especially on polymeric sugars such as cellulose, starch and xylan, which release fermentable sugars upon enzymatic hydrolysis. In this paper we present a detailed and complete compositional analysis procedure suggested for DDGS and wet distillers' grains, as well as the resulting compositions completed by three different research groups. Polymeric sugars, crude protein, crude oil and ash contents of DDGS and wet distillers' grains were accurately and reproducibly determined by the compositional analysis procedure described in this paper.

  11. Investigation of lattice defects and compositional gradients in Cu(In,Ga)Se{sub 2} thin films for solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Dietrich, Jens; Boit, Christian [Department of Semiconductor Devices, Berlin University of Technology, Einsteinufer 19, 10587 Berlin (Germany); Abou-Ras, Daniel; Rissom, Thorsten; Unold, Thomas; Schock, Hans-Werner [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany)

    2011-07-01

    Cu(In,Ga)Se{sub 2} absorber layers used in thin-film solar cells exhibit, when grown in a multi-stage process, compositional gradients of gallium and indium, dependent on process parameters such as the Ga content. The high lateral resolution of transmission electron microscopy (TEM) imaging and energy-dispersive X-ray spectroscopy (EDX) allows the determination of lattice defects and the elemental concentrations at identical sample positions. Cross-sectional TEM samples of ZnO/CdS/Cu(In,Ga)Se{sub 2}/Mo/glass stacks were prepared with varying [Ga]/([In]+[Ga]) ratio in the absorber. The shape of the Ga distribution was measured by means of EDX and differs for the various [Ga]/([In]+[Ga]) ratios. Linear (dislocations) and planar defects (stacking faults, microtwins) were studied by means of TEM bright field and dark field images along the lengths of the Cu(In,Ga)Se{sub 2} layers. Strong Ga compositional gradients were found even within individual grains. It appears that these Ga gradients correlate with the occurrence of dislocation networks in large grains (diameter > 1 {mu}m). We assume that these dislocations compensate for lattice mismatch due to the change in composition in this area of the lattice.

  12. Organic fouling of thin-film composite polyamide and cellulose triacetate forward osmosis membranes by oppositely charged macromolecules.

    Science.gov (United States)

    Gu, Yangshuo; Wang, Yi-Ning; Wei, Jing; Tang, Chuyang Y

    2013-04-01

    Fouling of cellulose triacetate (CTA) and thin-film composite (TFC) forward osmosis (FO) membranes by organic macromolecules were studied using oppositely charged lysozyme (LYS) and alginate (ALG) as model foulants. Flux performance and foulant deposition on membranes were systematically investigated for a submerged membrane system. When an initial flux of 25 L/m(2)h was applied, both flux reduction and foulant mass deposition were severe for feed water containing the mixture of LYS and ALG (e.g., 50% LYS and 50% ALG at a total foulant concentration of 100 mg/L). In comparison, fouling was much milder for feed water containing either LYS or ALG alone. Compared to the CTA FO membrane, the TFC FO membrane showed greater fouling propensity under mild FO fouling conditions due to its much rougher surface. Nevertheless, under severe FO fouling conditions, fouling was dominated by foulant-deposited-foulant interaction and membrane surface properties played a less important role. Furthermore, when the feed water contained both LYS and ALG in sufficient amount, the deposited cake layer foulant composition (i.e., the LYS/ALG mass ratio) was not strongly affected by membrane types (CTA versus TFC) nor testing modes (pressure-driven NF mode versus osmosis-driven FO mode). In contrast, solution chemistry such as pH and calcium concentration had remarkable effect on the cake layer composition due to their effects on foulant-foulant interaction.

  13. Ultra-thin polytetrafluoroethene/Nafion/silica composite membrane with high performance for vanadium redox flow battery

    Science.gov (United States)

    Teng, Xiangguo; Dai, Jicui; Bi, Fangyuan; Yin, Geping

    2014-12-01

    Ultra-thin and high performance polytetrafluoroethene (PTFE)/Nafion/silica composite membrane has been successfully prepared by solution casting and sol-gel method for all vanadium redox flow battery (VRB). Thickness of ∼25 μm polytetrafluoroethene/Nafion (P/N) membrane is first prepared by impregnating porous PTFE membrane with Nafion solution, and then the P/N membrane is immersed in tetraethoxysilane (TEOS) solution to prepare PTFE/Nafion/silica (P/N/S) composite membranes. The chemical structures of membranes are investigated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR), which prove that the Nafion resin and silica are well impregnated in PTFE membrane. The water uptake, proton conductivity, vanadium permeability and VRB single cell tests of the composite membrane are also investigated in detail. At 80 mA cm-2, coulombic efficiency, voltage efficiency and energy efficiency of the VRB with P/N/S-7 (7 wt.% SiO2 in P/N/S) membrane are 93.9%, 87.2% and 81.9%, respectively. Furthermore, the self-discharge rate of the VRB with P/N/S membrane is much slower than that of the VRB with P/N membrane, which indicates that the membrane has good vanadium block ability. Fifty cycles charge-discharge test proves that the P/N/S membrane is very stable and possesses high chemical stability under the strong acid solutions.

  14. A composite thin vacuum window for the CLAS photon tagger at Jefferson lab

    CERN Document Server

    Matthews, S K; O'Brien, J T; Sober, D I

    1999-01-01

    The construction of a thin vacuum window, currently in use on the CLAS photon tagging system at the Thomas Jefferson National Accelerator Facility, is described. A layer of woven Kevlar cloth supports a much thinner membrane of aluminized Mylar. Notable features of this particular window include its overall length (9.6 m), and the fact that the entire load is supported by the epoxy seal with no mechanical clamping around the edges. Results from a diverse program of materials testing, including a clear dependence of leak rate on relative humidity, are also reported.

  15. Nonlinear Elastic Deformation of Thin Composite Shells of Discretely Variable Thickness

    Science.gov (United States)

    Lutskaya, I. V.; Maksimyuk, V. A.; Storozhuk, E. A.; Chernyshenko, I. S.

    2016-11-01

    A method for analyzing the stress-strain state of nonlinear elastic orthotropic thin shells with reinforced holes and shells of discretely variable thickness is developed. The reference surface is not necessarily the midsurface. The constitutive equations are derived using Lomakin's theory of anisotropic plasticity. The methods of successive approximations and variational differences are used. The Kirchhoff-Love hypotheses are implemented using Lagrange multipliers. The method allows analyzing the stress-strain state of shells with arbitrarily varying thickness and ribbed shells. The numerical results are presented in the form of tables and analyzed

  16. Characterization of thermally evaporated CZTSe thin films used by compositionally controlled alloys

    Science.gov (United States)

    Sripan, Chinnaiyah; Ganesan, R.; Naik, Ramakanta; Viswanath, A. Kasi

    2016-12-01

    Stoichiometric adjusted Cu2Zn1.5Sn1.2Se4+x (CZTSe) alloys were successfully prepared by a thermal molten method. The pure phase was formed at x = 0.8 as confirmed by XRD and Raman spectroscopy. The bulk alloy was used for thin film coating by thermal evaporation method. The prepared films were characterized by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), and FT-IR spectroscopy. The XRD and Raman spectroscopy analysis revealed the formation of polycrystalline CZTSe thin films with tetragonal crystal structure after annealing of 450 °C. Diode characteristics were studied on the Mo/CZTSe/CdS sandwich geometry. The oxidation state of the selenized film was studied by XPS. The optical band gap of the CZTSe film was about 1.42 eV, which was varying with annealing and selenization condition. The carrier concentration, resistance and mobility of the selenized films were found to be 5.2 × 1015 cm-3, 2.2 KΩ/square and 5.5 cm2 V-1s-1 respectively and the conduction type was p-type. This study sheds light on the effect of annealing and selenization on various phases modifications and the light-harvesting capability of CZTSe solar cells.

  17. Developing thin-film-composite forward osmosis membranes on the PES/SPSf substrate through interfacial polymerization

    KAUST Repository

    Wang, Kaiyu

    2011-04-22

    A new scheme has been developed to fabricate high-performance forward osmosis (FO) membranes through the interfacial polymerization reaction on porous polymeric supports. p-Phenylenediamine and 1,3,5-trimesoylchloride were adopted as the monomers for the in-situ polycondensation reaction to form a thin aromatic polyamide selective layer of 150 nm in thickness on the substrate surface, a lab-made polyethersulfone (PES)/sulfonated polysulfone (SPSf)-alloyed porous membrane with enhanced hydrophilicity. Under FO tests, the FO membrane achieved a higher water flux of 69.8 LMH when against deionized water and 25.2 LMH when against a model 3.5 wt % NaCl solution under 5.0 M NaCl as the draw solution in the pressure-retarded osmosis mode. The PES/SPSf thin-film-composite (TFC)-FO membrane has a smaller structural parameter S of 238 μm than those reported data. The morphology and topology of substrates and TFC-FO membranes have been studied by means of atomic force microscopy and scanning electronic microscopy. © 2011 American Institute of Chemical Engineers (AIChE).

  18. Compositionally and structurally modified SrTiO{sub 3} thin films prepared by chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Spitzner, Dirk; Gutmann, Emanuel; Reibold, Marianne; Meyer, Dirk C. [Institut fuer Strukturphysik, Technische Universitaet Dresden (Germany); Mahltig, Boris [GMBU e.V., Arbeitsgruppe Funktionelle Schichten, Dresden (Germany)

    2009-07-01

    For electronic and architectural design of functional electroceramic devices, materials with a perovskite-type of structure play a major role. For high-k dielectric, sensing and thermal switching applications the introduction of Barium into SrTiO{sub 3}(STO) allows tuning the electrical properties by tuning the paraelectric-to-ferroelectric transition temperature. For thin film preparation a classic sol-gel route was modified by refluxing as well as solvothermal treatment of the as-synthesized sols. For treated sols the decomposition, phase evolution and transition behaviour differed and from X-ray diffraction (XRD) we observed a supression of foreign phases and a higher degree of compositional homogeneity. In this context also the homologous series of perovskite-related Ruddlesden-Popper (RP) phases promise an engineering of electrical properties by selecting a specific member. Exemplarily we realised the chemical solution deposition of epitaxial thin films of SrO(SrTiO{sub 3}){sub n} RP phases (n=1,2,3) on STO substrates. Structural characteristics of the films were analysed by means of XRD and HRTEM. An application as buffer layers exhibiting tuneable dielectric properties is conceivable.

  19. Formation of nanodots and enhancement of thermoelectric power induced by ion irradiation in PbTe:Ag composite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bala, Manju, E-mail: manjubala474@gmail.com [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Meena, Ramcharan; Gupta, Srashti; Pannu, Compesh [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Tripathi, Tripurari S. [Aalto University, Värmemansgränden 2, 02150 Espoo (Finland); Varma, Shikha [Institute of Physics, Bhubaneshwar, Odisha 751005 (India); Tripathi, Surya K. [Department of Physics, Panjab University, Chandigarh 160 014 (India); Asokan, K., E-mail: asokaniuac@gmail.com [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Avasthi, Devesh K. [Amity University, Noida 201313, Uttar Pradesh (India)

    2016-07-15

    Present study demonstrates an enhancement in thermoelectric power of 10% Ag doped PbTe (PbTe:Ag) thin films when irradiated with 200 keV Ar ion. X-ray diffraction showed an increase in crystallinity for both PbTe and PbTe:10Ag nano-composite films after Ar ion irradiation due to annealing of defects in the grain boundaries. The preferential sputtering of Pb and Te ions in comparison to Ag ions resulted in the formation of nano-dots. This was further confirmed by X-ray photoelectron spectroscopy (XPS). Such an enhancement in thermoelectric power of irradiated PbTe:10Ag films in comparison to pristine PbTe:10Ag film is attributed to the decrease in charge carrier concentration that takes part in the transport process via restricting the tunneling of carriers through the wider potential barrier formed at the interface of nano-dots.

  20. Composition and structure of CuInSe2 thin films prepared by vacuum evaporation of the constituent elements

    Science.gov (United States)

    Dhere, N. G.; Lourenco, M. C.; Dhere, R. G.; Kazmerski, L. L.

    1984-11-01

    The characteristics of CuInSe2 thin film solar cells produced by a three-source deposition method were investigated. The films were deposited at 350 C, followed by 30 min annealing at the same temperature. The compositions of the cells and intracell fractional variations were dependent on the proximity to the film source during formation. A chalcopyrite CuInSe2 structure was observed in X-ray diffraction patterns and high energy electron diffraction studies of the films on NaCl single crystal substrates. Grain sizes ranged from 0.2-0.6 micron, and the films had a band gap in the 1.02-1.04 eV interval.

  1. Ultra thin films of gadolinium deposited by evaporation in ultra high vacuum conditions: Composition, growth and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Herrera-Sancho, O.A.; Castro-Gonzalez, D.; Araya-Pochet, J.A. [Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Escuela de Fisica, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Vargas-Castro, W.E., E-mail: william.vargascastro@ucr.ac.cr [Centro de Investigacion en Ciencia e Ingenieria de Materiales, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica); Escuela de Fisica, Universidad de Costa Rica, 2060 San Pedro, San Jose (Costa Rica)

    2011-02-01

    Ultra-thin gadolinium films with thicknesses between 8 and 101 A were deposited on AT-cut crystalline quartz substrates under ultra high vacuum conditions, and subsequently subjected to composition and morphologic characterization through X-ray photo-spectroscopy analysis and atomic force microscopy. Oxygen contamination is found on the samples, and its amount is estimated in terms of the thickness of an oxygen layer over the gadolinium films after subtracting the contribution to the XPS spectra of the underlying background. Atomic force microscope pictures provide evidence of having metal island films, with two growing regimes: the Volmer-Weber mode for the thinner films considered and the Stranski-Krastanov growing mode for the thicker ones. From evaluation of the sticking coefficient, the shape of the islands is approximated in terms of oblate spheroid caps and variation of the contact angle with film mass thickness is reported.

  2. Quasi-Static Crushing Simulation Research and Failure Mode Analysis of Composite Thin-Walled C-Channel Specimen

    Directory of Open Access Journals (Sweden)

    XIE Jiang

    2017-04-01

    Full Text Available To study the crushing energy-absorbing characteristics and failure mode, the multi-shells finite element model of composite thin-walled C-channel specimen was established based on the quasi-static crushing test results. The simulation results show that the delamination failure, local buckling and beam bending failure of C-channel specimen can be simulated with the multi-shells finite element model. The load-displacement curve well fits the test results, and the deviation of initial peak load (Fmax, specific energy absorption (Es and crushing mean load (Fmean is small compared with the test results. The initial peak load of C-channel specimen is larger and the load efficiency is lower, so it is necessary to further reduce the initial peak load by the design optimization.

  3. Preparation and Characterization of Thin-Film Composite Membrane with Nanowire-Modified Support for Forward Osmosis Process

    Directory of Open Access Journals (Sweden)

    Ze-Xian Low

    2015-03-01

    Full Text Available Internal concentration polarization (ICP in forward osmosis (FO process is a characteristic problem for asymmetric thin-film composite (TFC FO membrane which leads to lower water flux. To mitigate the ICP effect, modification of the substrates’ properties has been one of the most effective methods. A new polyethersulfone-based ultrafiltration membrane with increased surface porosity and high water flux was recently produced by incorporating Zn2GeO4 nanowires. The composite membrane was used as a substrate for the fabrication of TFC FO membrane, by coating a thin layer of polyamide on top of the substrate. The substrate and the nanowires were characterized by a range of techniques such as SEM, XRD, and contact angle goniometry. The water permeability and molecular weight cut-offs (MWCO of the substrate; and the FO performance of the TFC membrane were also determined. The Zn2GeO4-modified membrane showed ~45% increase in water permeability and NaCl salt rejection of 80% under RO mode. In FO mode, the ratio of water flux to reverse solute flux was also improved. However, lower FO flux was obtained which could be due to ICP. The result shows that Zn2GO4 nanowire may be used as a modifier to the substrate to improve the quality of the polyamide layer on the substrate to improve the flux and selectivity, but not as effective in reducing ICP. This work demonstrates that the incorporation of nanomaterials to the membrane substrate may be an alternative approach to improve the formation of polyamide skin layer to achieve better FO performance.

  4. Exchange bias and anisotropy analysis of nano-composite Co{sub 84}Zr{sub 16}N thin films

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Jitendra, E-mail: jitendra@ceeri.ernet.in [CSIR-Central Electronics Engineering Research Institute, Pilani, Rajasthan 333031 (India); Academy of Scientific and Innovative Research, Chennai 600113 (India); Taube, William Ringal [CSIR-Central Electronics Engineering Research Institute, Pilani, Rajasthan 333031 (India); Academy of Scientific and Innovative Research, Chennai 600113 (India); Ansari, Akhtar Saleem [Department of Applied Physics, Aligarh Muslim University, Aligarh 202002 (India); Gupta, Sanjeev Kumar [Academy of Scientific and Innovative Research, Chennai 600113 (India); Kulriya, Pawan Kumar [Inter-University Accelerator Centre, New Delhi 110067 (India); Akhtar, Jamil [CSIR-Central Electronics Engineering Research Institute, Pilani, Rajasthan 333031 (India); Academy of Scientific and Innovative Research, Chennai 600113 (India)

    2015-03-15

    Nano-composite Co{sub 84}Zr{sub 16}N (CZN) films were prepared by reactive co-sputter deposition. As-deposited CZN films have not shown any exchange bias effect. But annealed (390 K) and field cooled samples have shown exchange bias phenomena. The observed exchange bias is attributed to inter-cluster exchange coupling between ferromagnetic and antiferromagnetic nano-composite phase. High resolution transmission electron microscope study reveals that, the CZN films are composed of ordered and crystalline ferromagnetic Cobalt nano-clusters embedded in an antiferromagnetic matrix. X-ray diffraction confirms the poly-crystalline growth of the CZN films with a preferred fcc (622) phase formation. In-plane anisotropy of the exchange biased films was investigated by rotational magnetization curve, and the analysis shows that the magnetization reversal behaves according to the coherent rotation of the magnetic moment vector. Effectively, exchange bias effect in such single layer films could be attributed to co-existing antiferromagnetic and ferromagnetic phase within the single layer. Such single layer nano-composite films can be a possible alternative to the bilayer combination of antiferromagnetic/ferromagnetic exchange biased films and are ideally suited for spintronics and tunnel junction applications. - Highlights: • Exchange bias effect observed in 390 K annealed and field cooled single layer nanocomposite Co{sub 84}Zr{sub 16}N (CZN) thin films. • CZN films are composed of ordered and crystalline ferromagnetic Cobalt nano-clusters embedded in antiferromagnetic matrix. • Uniaxial magnetic anisotropy investigated by rotational magnetization curve, and magnetization reversal behaves according to coherent rotation of magnetic moment vector. • Co-existing FM and AF phases in composite matrix are lead to extraordinary EB behavior.

  5. Kinetics of Ni:C Thin Film Composition Formation at Different Temperatures and Fluxes

    Directory of Open Access Journals (Sweden)

    Gediminas KAIRAITIS

    2013-09-01

    Full Text Available In this work analysis considering Ni:C thin films growth on thermaly oxidized Si substrate by proposed kinetic model is presented. Model is built considering experimental results where microstructure evolution as a function of the substrate temperature and metal content of Ni:C nanocomposite films grown by hyperthermal ion deposition is investigated. The proposed kinetic model is based on the rate equations and includes processes of adsorption, surface segregation, diffusion, chemical reactions of constituents. The experimental depth profile curves were fitted by using proposed model. The obtained results show a good agreement with experiment taking into account concentration dependent diffusion. It is shown by modeling that with the increase of substrate temperature the process of nickel surface segregation becomes most important. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5234

  6. Electrical and thermoelectric properties of different compositions of Ge-Se-In thin films

    Science.gov (United States)

    Aly, K. A.; Dahshan, A.; Abbady, Gh.; Saddeek, Y.

    2016-09-01

    The effect of temperature in the range of 300-450 K and the indium content on the electrical and thermoelectric properties of Ge20Se80-xInx (0.0≤x≤24 at%) chalcogenide glassy thin films have been studied. From dc electrical and thermoelectric measurements, it was observed that the activation energies for electrical conductivity (ΔE) and for thermoelectric (ΔEs) decrease while the conductivity (σ) and Seebeck coefficient (S) increase upon introducing In into the Ge-Se glasses. In contrast to the behavior obtained with Bi or Pb doping, In incorporated in Ge-Se does not lead to a p-to n-type conduction inversion. The power factor (P) which is strongly depends on both of the Seebeck coefficient and the electrical conductivity. According to the obtained results, the Ge20Se80-xInx films can be considered potential candidates for incurring high action thermoelectric materials.

  7. Transparent conducting electrodes based on thin, ultra-long copper nanowires and graphene nano-composites

    Science.gov (United States)

    Zhu, Zhaozhao; Mankowski, Trent S.; Balakrishnan, Kaushik; Shikoh, Ali Sehpar; Touati, Farid; Benammar, Mohieddine A.; Mansuripur, Masud; Falco, Charles M.

    2014-10-01

    High aspect-ratio ultra-long (> 70 μm) and thin (< 50 nm) copper nanowires (Cu-NW) were synthesized in large quantities using a solution-based approach. The nanowires, along with reduced graphene-oxide sheets, were coated onto glass as well as plastic substrates, thus producing transparent conducting electrodes. Our fabricated transparent electrodes achieved high optical transmittance and low sheet resistance, comparable to those of existing Indium Tin Oxide (ITO) electrodes. Furthermore, our electrodes show no notable loss of performance under high temperature and high humidity conditions. Adaptations of such nano-materials into smooth and ultrathin films lead to potential alternatives for the conventional tin-doped indium oxide, with applications in a wide range of solar cells, flexible displays, and other opto-electronic devices.

  8. Kinetics of Ni:C Thin Film Composition Formation at Different Temperatures and Fluxes

    Directory of Open Access Journals (Sweden)

    Gediminas KAIRAITIS

    2013-09-01

    Full Text Available In this work analysis considering Ni:C thin films growth on thermaly oxidized Si substrate by proposed kinetic model is presented. Model is built considering experimental results where microstructure evolution as a function of the substrate temperature and metal content of Ni:C nanocomposite films grown by hyperthermal ion deposition is investigated. The proposed kinetic model is based on the rate equations and includes processes of adsorption, surface segregation, diffusion, chemical reactions of constituents. The experimental depth profile curves were fitted by using proposed model. The obtained results show a good agreement with experiment taking into account concentration dependent diffusion. It is shown by modeling that with the increase of substrate temperature the process of nickel surface segregation becomes most important. DOI: http://dx.doi.org/10.5755/j01.ms.19.3.5234

  9. Leakage current mechanisms and their dependence on composition in silicon carbonitride thin films

    Science.gov (United States)

    Vijayakumar, Vishnuvardhanan; Varadarajan, Bhadri

    2015-04-01

    Electrical conduction in amorphous silicon carbonitride (a-SiCN:H) thin films deposited by plasma enhanced chemical vapor deposition (PECVD) is investigated for varying carbon to nitrogen ratios at room temperature. Films deposited with a lower carbon/nitrogen ratio showed two modes of electrical conduction; namely, Schottky emission mode below 2.3 MV cm-1 electric field and Poole-Frenkel mode from 2.3 MV cm-1 up to the breakdown field. Films with higher carbon/nitrogen ratios showed only Poole-Frenkel mode of conduction throughout the entire range of operation up to the breakdown field. The carbon rich films exhibited higher leakage currents attributed to its shallow defect energy levels leading to its higher Poole-Frenkel conductivity.

  10. Influence of bath composition on the electrodeposition of cobalt-molybdenum amorphous alloy thin films

    Institute of Scientific and Technical Information of China (English)

    Qiaoying Zhou; Hongliang Ge; Guoying Wei; Qiong Wu

    2008-01-01

    Cobalt-molybdenum (Co-Mo) amorphous alloy thin films were deposited on copper substrates by the electrochemical method at pH 4.0. Among the experimental electrodeposition parameters, only the concentration ratio of molybdate to cobalt ions ([ MoO2-4 ]/[CO2+]) was varied to analyze its influence on the mechanism of induced cobalt-molybdenum codeposition. Voltammetry was one of the main techniques, which was used to examine the voltammetric response, revealing that cobalt-molybdenum codeposi-tion depended on the nature of the species in solution. To correlate the type of the film to the electrochemical response, various co-bait-molybdenum alloy thin films obtained from different [ MoO2-4]/[Co2+] solutions were tested. Crack-free homogeneous films could be easily obtained from the low molybdate concentrations ([ MoO2-4]/[Co2+]≈0.05) applying low deposition potentials.Moreover, the content of molybdenum up to 30wt% could be obtained from high molybdate concentration; in this case, the films showed cracks. The formation of these cracked films could be predicted from the observed distortions in the curves of electric cur-rent-time (j-t) deposition transients. The films with amorphous stmeture were obtained. The hysteresis loops suggested that the easily film were obtained when the deposition potential was -1025 mV, and [ MoO2-4]/[Co2+] was 0.05 in solution, which exhibited a nicer soft-magnetic response.

  11. Ascorbate electro-oxidation by modified electrodes: Polypyrrole and polypyrrole/Ni(OH){sub 2} composite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues da Silva, Marcelo [Faculdade de Engenharia/Colegio Tecnico Industrial, UNESP, CP 473, 17033-360 Bauru, SP (Brazil); Ferreira, Marcelo Silva [Departamento de Quimica, Centro de Ciencias Exatas, UEL, CP 6001, 86051-980 Londrina, PR (Brazil); Dall' Antonia, Luiz Henrique, E-mail: luizh@uel.br [Departamento de Quimica, Centro de Ciencias Exatas, UEL, CP 6001, 86051-980 Londrina, PR (Brazil)

    2012-08-01

    The present paper describes the utilization of polypyrrole and the composite of polypyrrole doped with nickel hydroxide modified electrodes toward the catalytic oxidation of ascorbate. Films were potentiostatically deposited onto a glassy carbon surface and Fluor-doped tin oxide glass for different times. The physical characterization was performed using the low angle X-ray diffraction technique. Furthermore, the films were electrochemically characterized using cyclic voltammetry. The X-ray diffraction results show the existence of different polymorphic phases of nickel hydroxide in the polymer matrix, and the {beta}-Ni(OH){sub 2} phase appears to be dominant. The cyclic voltammetry profile in KOH solution shows the presence of two redox peaks that are related to the Ni{sup II}/Ni{sup III} and Ni{sup III}/Ni{sup II} couples, at approximately 0.5 and 0.35 V, respectively. The reversible electro-oxidation of ascorbate was observed on the surface of the polypyrrole and composite films. The analytical curves obtained using voltammetric techniques show a linear relationship between the faradaic current and the increase of the ascorbic acid concentration. The sensitivity of these films, which is obtained from the slope of the analytical curves, shows that the composite film is more electroactive than the polypyrrole film: 133.4 mA L mol{sup -1} cm{sup -2} and 83.8 mA L mol{sup -1} cm{sup -2}, respectively. The rate constants of the catalytic ascorbate electro-oxidation were also reported, where the mean values were found to be 217.74 M{sup -1} s{sup -1} and 54.37 M{sup -1} s{sup -1}, for the composite and polypyrrole films, respectively. The low cost of polypyrrole doped with Ni(OH){sub 2} composite electrodes presents a more selective and high sensitivity to determine ascorbic acid concentration. - Highlights: Black-Right-Pointing-Pointer Electrochemical synthesis of polypyrrole and nickel hydroxide composite thin films Black-Right-Pointing-Pointer High sensitivity

  12. Oscillations of composition near the external surface of Y-Ba-Cu-O thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bakunin, O. M.; Klotsman, S. M.; Matveev, S. A.; Stepanov, K. A.

    1989-07-03

    An Auger electron spectroscopy study has been made of the depth profiles of films of Y-Ba-Cu-O compounds. The films were produced by electron beam and ion plasma sputtering onto various substrate types. The specimens were annealed in air at temperatures ranging between 450 and 900 /degree/C. The effective diffusion coefficients for the film and substrate constituents have been estimated. The depth profiles of films annealed at 600 /degree/C reveal composition oscillations in the region adjacent to the surface. These composition oscillations are assumed to arise from the phase transformations that occur at 600 /degree/C in films of the Y-Ba-Cu-O system.

  13. Fabrication for multilayered composite thin films by dual-channel vacuum arc deposition.

    Science.gov (United States)

    Dai, Hua; Shen, Yao; Wang, Jing; Xu, Ming; Li, Liuhe; Li, Xiaoling; Cai, Xun; Chu, Paul K

    2008-06-01

    A flexible dual-channel curvilinear electromagnetic filter has been designed and constructed to fabricate multilayered composite films in vacuum arc ion plating. The filter possesses two guiding channels and one mixing unit. Multilayered TiN/AlN and TiAlN composite films can be produced by controlling the frequency or interval of the two cathodes. The x-ray photoelectron spectroscopy and low-angle x-ray diffraction results reveal the periodic Ti and Al structures in the TiN/AlN films. The TiAlN films exhibit a smooth surface morphology confirming effective filtering of macroparticles by the filter. High temperature oxidation conducted at 700 degrees C for an hour indicates that the weight increment in the TiAlN films produced by the dual filter is only half of that of the TiAlN films produced without a filter, thereby showing better resistance against surface oxidation.

  14. Fabrication for multilayered composite thin films by dual-channel vacuum arc deposition

    Science.gov (United States)

    Dai, Hua; Shen, Yao; Wang, Jing; Xu, Ming; Li, Liuhe; Li, Xiaoling; Cai, Xun; Chu, Paul K.

    2008-06-01

    A flexible dual-channel curvilinear electromagnetic filter has been designed and constructed to fabricate multilayered composite films in vacuum arc ion plating. The filter possesses two guiding channels and one mixing unit. Multilayered TiN /AlN and TiAlN composite films can be produced by controlling the frequency or interval of the two cathodes. The x-ray photoelectron spectroscopy and low-angle x-ray diffraction results reveal the periodic Ti and Al structures in the TiN /AlN films. The TiAlN films exhibit a smooth surface morphology confirming effective filtering of macroparticles by the filter. High temperature oxidation conducted at 700°C for an hour indicates that the weight increment in the TiAlN films produced by the dual filter is only half of that of the TiAlN films produced without a filter, thereby showing better resistance against surface oxidation.

  15. Relation between surface properties of thin composite films and osteoblast behaviour in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Polak, B [Department of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00 664, Warsaw (Poland); Olkowski, R [Department of Biophysics and Human Physiology, Medical University of Warsaw, Chalubinskiego 5, 02 004 Warsaw (Poland); Kobiela, T [Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, 02-668 Warsaw (Poland); Lewandowska-Szumiel, M [Department of Biophysics and Human Physiology, Medical University of Warsaw, Chalubinskiego 5, 02 004 Warsaw (Poland); Fabianowski, W [Department of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00 664, Warsaw (Poland)

    2007-07-18

    Si supports for cell culture were modified using poly(acrylic acid) (PAA) and bentonite in order to obtain 'sandwich'-like structures. A layer of PAA cast from water solution was followed with a bentonite layer also cast from water dispersion, then another PAA layer and so on up to six layers. The prepared surfaces had different physical and chemical properties like thickness, topography and elasticity. Chemical composition was characterized by Raman spectroscopy. The elastic properties and topography of modified sandwich-like surfaces were evaluated using nanoindentation and atomic force microscopy measurements. In the next step bone cells were cultured on such modified surfaces composed of one to six layers. The influence of the substrate surface properties on the growth and behaviour of human bone derived cells (HBDC) was studied. The influence of surface topography, elasticity and chemical composition on cells is discussed.

  16. Influence of compliance of the substrate materials on polymerization contraction stress in thin resin composite layers.

    Science.gov (United States)

    Alster, D; Venhoven, B A; Feilzer, A J; Davidson, C L

    1997-02-01

    The present study determined in a laboratory set-up the influence of compliance of the substrate material on polymerisation contraction stress for various thicknesses of bonded dental resin composite films. When the compliance of the tensilometer set-up was increased from 0.029 micron MPa-1 to 0.150 micron MPa-1, the contraction stress in films with a thickness of 100 microns and a diameter of 5.35 mm decreased from 22 to 7 MPa. For the 700 microns samples the stress decreased from 12 to 11 MPa. It was concluded that if compliance from the substrate materials is possible, a thinner resin composite film may effect a more reliable bond.

  17. Swift heavy ion irradiation induced phase transformation in undoped and niobium doped titanium dioxide composite thin films

    Science.gov (United States)

    Gautam, Subodh K.; Chettah, Abdelhak; Singh, R. G.; Ojha, Sunil; Singh, Fouran

    2016-07-01

    Study reports the effect of swift heavy ion (SHI) irradiation induced phase transformation in undoped and Niobium doped anatase TiO2 composite thin films. Investigations were carried out at different densities of electronic excitations (EEs) using 120 MeV Ag and 130 MeV Ni ions irradiations. Films were initially annealed at 900 °C and results revealed that undoped films were highly stable in anatase phase, while the Nb doped films showed the composite nature with the weak presence of Niobium penta-oxide (Nb2O5) phase. The effect at low density of EEs in undoped film show partial anatase to rutile phase transformation; however doped film shows only further growth of Nb2O5 phase beside the anatase to rutile phase transformation. At higher density of EEs induced by Ag ions, registered continuous ion track of ∼3 nm in lattice which leads to nano-crystallization followed by decomposition/amorphization of rutile TiO2 and Nb2O5 phases in undoped and doped films, respectively. However, Ni ions are only induced discontinuous sequence of ion tracks with creation of damage and disorder and do not show amorphization in the lattice. The in-elastic thermal spike calculations were carried out for anatase TiO2 phase to understand the effect of EEs on anatase to rutile phase transformation followed by amorphization in NTO films in terms of continuous and discontinuous track formation by SHI irradiation.

  18. Preparation and tribological properties of Sol-Gel TiO2-ZrO2 composite thin films

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    High oriented TiO2-ZrO2 composite thin films on Si (100) and glass sheet were suc-cessfully prepared by sol-gel process followed by dip-coating the ethanol solution of zirconiumoxychloride and titanium tetrachloride. The sol-gel process, microstructure, morphology and tri-bological properties of TiO2 -ZrO2 films were investigated using TGA, DSC, XPS, XRD, AFM anddynamic-static tribometer. The results show that the TiO2-ZrO2films are dense, homogeneous andat a complete tetragonal phase with an excellent antiwear and friction reduction performance. Un-der 0.5N applied load, the friction coefficient is 0.14-0.20 and the antiwear life is more than 5000sliding cycles for both TiO2-ZrO2/ AISI 52100 steel and TiO2-ZrO2/ Si3N4. SEM observation sug-gests that wear mechanism of TiO2 -ZrO2 composite film under low load was fatigue wear, andunder high load was adhesive wear. The TiO2 -ZrO2 films show potential applications as coatingsfor antiwear and friction reduction under the harsh condition.

  19. Assembly of gold composite thin films by spontaneous reduction of subphase chloroaurate anions beneath vitamin E Langmuir monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L. [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China); Department of Chemistry-Biology, Suzhou College, Suzhou 234000 (China); Shen, Y.H. [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China)], E-mail: s_yuhua@163.com; Xie, A.J.; Li, S.K.; Qiu, L.G.; Li, Y.M. [School of Chemistry and Chemical Engineering, Anhui University, Hefei 230039 (China)

    2007-09-15

    Gold composite thin films were generated by the spontaneous reduction of chloroaurate (AuCl{sub 4}{sup -}) ions beneath vitamin E (VE) Langmuir monolayer. The monolayer and gold nanocomposite LB films were then characterized by surface pressure-area ({pi}-A) isotherms, ultraviolet-visible spectroscopy (UV-vis), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction analysis (XRD), respectively. The results showed that the limiting area/VE molecule on the HAuCl{sub 4} solution subphase was larger than that on the pure water subphase, and it increased with reaction time. The morphologies of Au particles such as spherical-like, triangular and multiply-twinned particles (MTPs) could be observed. The XRD pattern indicated that the gold particles in LB films were face-centered cubic (fcc) polycrystalline. The plasmon absorption intensities of gold composite LB films increased with the film thickness, which suggested that the monolayer containing gold particles could be transferred successfully onto the substrates.

  20. Thermal effect on dynamics of thin and thick composite laminated microbeams by modified couple stress theory for different boundary conditions

    Science.gov (United States)

    Ghadiri, Majid; Zajkani, Asghar; Akbarizadeh, Mohammad Reza

    2016-12-01

    In this article, thermal effect on free vibration behavior of composite laminated microbeams based on the modified couple stress theory is presented. The proposed anisotropic model is developed by using a variational formulation. The governing equations and boundary conditions are obtained based on a modified couple stress theory and using the principle of minimum potential energy and considering different beam theories, i.e., Euler-Bernoulli, Timoshenko and Reddy beam theories. Unlike the classical beam theories, this model contains a material length scale parameter and can capture the size effect. Free vibration of a simply supported beam is solved by utilizing Fourier series. In addition, the fundamental frequency is achieved by using the generalized differential quadrature method for four types of cross-ply laminations with clamped-clamped, clamped-hinged and hinged-hinged boundary conditions for different beam theories. For investigating different parameters including temperature changes, material length scale parameter, beam thickness, some numerical results on different cross-ply laminated beams are presented. The fundamental frequency of different thin and thick beam theories is investigated by increasing slenderness ratio and thermal loads. The results prove that the modified couple stress theory increases the natural frequency under the thermal effects for free vibration of composite laminated microbeams.

  1. Thin-walled composite tubes using fillers subjected to quasistatic axial compression

    Science.gov (United States)

    AL-Qrimli, Haidar F.; Mahdi, Fadhil A.; Ismail, Firas B.; Alzorqi, Ibrahim S.

    2015-04-01

    It has been demonstrated that composites are lightweight, fatigue resistant and easily melded, a seemingly attractive alternative to metals. However, there has been no widespread switch from metals to composites in the automotive sector. This is because there are a number of technical issues relating to the use of composite materials that still need to be resolved including accurate material characterization, manufacturing and joining process. The total of 36 specimens have been fabricated using the fibre-glass and resin (epoxy) with a two different geometries (circular and corrugated) each one will be filled with five types of filler (Rice Husk, Wood Chips, Aluminium Chips, Coconut Fibre, Palm Oil Fibre) all these type will be compared with empty Tubes for circular and corrugated in order to comprehend the crashworthiness parameters (initial failure load, average load, maximum crushing load, load ratio, energy absorption, specific energy absorption, volumetric energy absorption, crushing force efficiency and crush strain relation) which are considered very sufficient parameters in the design of automotive industry parts. All the tests have been done using the “INSTRON Universal machine” which is computerized in order to simply give a high precision to the collection of the results, along with the use of quasi-static load to test and observe the behaviour of the fabricated specimens.

  2. Synthesis of Thin Film Composite Metal-Organic Frameworks Membranes on Polymer Supports

    KAUST Repository

    Barankova, Eva

    2017-06-01

    Since the discovery of size-selective metal-organic frameworks (MOF) researchers have tried to manufacture them into gas separation membranes. ZIF-8 became the most studied MOF for membrane applications mainly because of its simple synthesis, good chemical and thermal stability, recent commercial availability and attractive pore size. The aim of this work is to develop convenient methods for growing ZIF thin layers on polymer supports to obtain defect-free ZIF membranes with good gas separation properties. We present new approaches for ZIF membranes preparation on polymers. We introduce zinc oxide nanoparticles in the support as a secondary metal source for ZIF-8 growth. Initially the ZnO particles were incorporated into the polymer matrix and later on the surface of the polymer by magnetron sputtering. In both cases, the ZnO facilitated to create more nucleation opportunities and improved the ZIF-8 growth compared to the synthesis without using ZnO. By employing the secondary seeded growth method, we were able to obtain thin (900 nm) ZIF-8 layer with good gas separation performance. Next, we propose a metal-chelating polymer as a suitable support for growing ZIF layers. Defect-free ZIF-8 films with a thickness of 600 nm could be obtained by a contra-diffusion method. ZIF-8 membranes were tested for permeation of hydrogen and hydrocarbons, and one of the highest selectivities reported so far for hydrogen/propane, and propylene/propane was obtained. Another promising method to facilitate the growth of MOFs on polymeric supports is the chemical functionalization of the support surface with functional groups, which can complex metal ions and which can covalently bond the MOF crystals. We functionalized the surface of a common porous polymeric membrane with amine groups, which took part in the reaction to form ZIF-8 nanocrystals. We observed an enhancement in adhesion between the ZIF layer and the support. The effect of parameters of the contra-diffusion experiment

  3. Synthesis and Properties of High Strength Thin Film Composites of Poly(ethylene Oxide and PEO-PMMA Blend with Cetylpyridinium Chloride Modified Clay

    Directory of Open Access Journals (Sweden)

    Mohammad Saleem Khan

    2015-01-01

    Full Text Available Ion-conducting thin film composites of polymer electrolytes were prepared by mixing high MW poly(ethylene oxide (PEO, poly(methyl methacrylate (PMMA as a polymer matrix, cetylpyridinium chloride (CPC modified MMT as filler, and different content of LiClO4 by using solution cast method. The crystallinity, ionic conductivity (σ, and mechanical properties of the composite electrolytes and blend composites were evaluated by using XRD, AC impedance, and UTM studies, respectively. The modification of clay by CPC showed enhancement in the d-spacing. The loading of clay has effect on crystallinity of PEO systems. Blend composites showed better mechanical properties. Young’s modulus and elongation at break values showed increase with salt and clay incorporation in pure PEO. The optimum composition composite of PEO with 3.5 wt% of salt and 3.3 wt% of CPMMT exhibited better performance.

  4. Composition dependence of density of states in a-Se100−Sn thin films

    Indian Academy of Sciences (India)

    N Sharma; S P Singh; S Kumar

    2007-10-01

    The present paper reports the DC conductivity measurements at high electric fields in vacuum evaporated amorphous thin films of a-Se100−Sn ( = 0, 2, 4, 6) glassy alloys. Current–voltage (–) characteristics have been measured at various fixed temperatures. In these samples, at low electric fields, ohmic behaviour is observed. However, at high electric fields ( ∼ 104 V/cm), non-ohmic behaviour is observed. An analysis of the experimental data confirms the presence of space charge limited conduction (SCLC) in the glassy materials studied in the present case. From the fitting of the data to the theory of SCLC, the density of defect states (DOS) near Fermi level is calculated. Increase in DOS with increase in Sn concentration has been found which could be correlated with the electronegativity difference between the two elements used here in making the glassy alloys. The peculiar role of the element Sn as an impurity in the pure Se glassy alloy is also discussed.

  5. Organic-inorganic Hybrids Towards the Preparation of Nanoporous Composite Thin Films for Microelectronic Application

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Silicon containing materials have traditionally been used in microelectronic fabrication. Semiconductor devices often have one or more arrays of patterned interconnect levels that serve to electrically couple the individual circuit elements forming an integrated circuit. These interconnect levels are typically separated by an insulating or dielectric film. Previously, a silicon oxide film was the most commonly used material for such dielectric films having dielectric constants(k) near 4. 0. However, as the feature size is continuously scaling down, the relatively high k of such silicon oxide films became inadequate to provide efficient electrical insulation. As such, there has been an increasing market demand for materials with even lower dielectric constant for Interlayer Dielectric (ILD) applications, yet retaining thermal and mechanical integrity. We wish to report here our investigations on the preparation of ultra-low k ILD materials using a sacrificial approach whereby organic groups are burnt out to generate low k porous ORMOSIL films. We have been able to prepare a variety of organically modified silicone resins leading to highly microporous thin films, exhibiting ultra-low k from 1.80 to 2.87, and good to high modulus, 1.5 to 5.5 Gpa. Structure property influences on porosity, dielectric constant and modulus will be discussed.

  6. Electrical and thermoelectric properties of different compositions of Ge–Se–In thin films

    Energy Technology Data Exchange (ETDEWEB)

    Aly, K.A., E-mail: kamalaly2001@gmail.com [Physics Department, Faculty of Science and Arts Khulais, University of Jeddah (Saudi Arabia); Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt); Dahshan, A., E-mail: adahshan73@gmail.com [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt); Department of Physics, Faculty of Science for Girls, King Khalid University, Abha (Saudi Arabia); Abbady, Gh. [Department of Physics, Faculty of Science, Assuit University, Assuit (Egypt); Saddeek, Y. [Physics Department, Faculty of Science, Al-Azhar University, Assiut Branch, Assiut (Egypt)

    2016-09-15

    The effect of temperature in the range of 300–450 K and the indium content on the electrical and thermoelectric properties of Ge{sub 20}Se{sub 80−x}In{sub x} (0.0≤x≤24 at%) chalcogenide glassy thin films have been studied. From dc electrical and thermoelectric measurements, it was observed that the activation energies for electrical conductivity (ΔE) and for thermoelectric (ΔE{sub s}) decrease while the conductivity (σ) and Seebeck coefficient (S) increase upon introducing In into the Ge–Se glasses. In contrast to the behavior obtained with Bi or Pb doping, In incorporated in Ge–Se does not lead to a p-to n-type conduction inversion. The power factor (P) which is strongly depends on both of the Seebeck coefficient and the electrical conductivity. According to the obtained results, the Ge{sub 20}Se{sub 80−x}In{sub x} films can be considered potential candidates for incurring high action thermoelectric materials.

  7. Photocatalytic properties of thin films of ruthenium metallopolymers/gold nanoparticle: Polyoxometalate composites using visible excitation

    Institute of Scientific and Technical Information of China (English)

    朱杰

    2013-01-01

    Thin layers of an electrostatically associated adduct RuPVP-AuNP:POM formed between the polyoxomolybdate, [S2 Mo18 O62 ]4, the polycationic metallopolymer [Ru(bpy)2(PVP)10 ](ClO4)2 and DMAP-protected gold nanoparticle have been deposited onto electrodes using two separate methods, alternate immersion layer-by-layer assembly and pre-assembled drop-casting; PVP is poly(4-vinylpyridine), BPY is 2,2’-bipyridyl, and DMAP is 4-dimethylaminopyridine. Significantly, the efficiency of the photocatalysis depends markedly on the structure of the [RuPVP-AuNP:POM] even when photonic properties are very similar. Strikingly, despite their similar photonic properties, an additional optical transition is observed in UV-vis and the Raman spectra of pre-assembled drop cast [RuPVP-AuNP:POM], which was not seen in dip coated [RuPVP-AuNP:POM]. Importantly, this electronic communication enhances the photocatalytic oxidation of benzaldehyde by a factor of more than four. While there is clear evidence for photosensitisation in the drop cast not present for the dip coated systems, the magnitude of the photocurrent, i.e.,(82.2 6.6) nA·cm 2for pre-assembled drop cast [RuPVP-AuNP:POM] at a ruthenium to Au nanoparticle mole ratio of 48:1, is twice as large as that those found in [Ru-PVP:POM] film.

  8. Characterization of quasi-nano-sized TiCx-Ni-Fe thin composite sheet prepared by using self-propagating high-temperature synthesis reaction and electroforming

    Science.gov (United States)

    Choi, Yong

    2014-05-01

    Thin TiCx-Ni-Fe composites sheet was prepared by self-propagating high-temperature synthesis (SHS) and electroforming. The quasi-nano-sized titanium carbide particles were prepared by self-propagating high temperature synthesis (SHS) followed by mechanical milling and ultrasonic floating agitation for classifying particles. The composite sheet was fabricated by co-deposition of the classified titanium carbide particles in a modified Watts nickel bath containing iron chloride during nickel-iron electro-forming. Neutron diffraction showed that the non-stoichiometric number of titanium carbides formed by the SHS reaction were in the range of 0.68 to 0.97, which depended on the initial carbon sources. X-ray diffraction and electron probe micro-analysis revealed that co-deposition of the carbides in Ni-Fe bath during the electroforming process produced a thin TiCx-Ni-Fe composite sheet, in which quasi-nano-sized titanium carbides were embedded about 7 at.%. The average surface resistance of the thin composite sheet was 1.053 ohm/sq. The corrosion potential and rate of the composites in a 50% NaOH solution were -920.6 mVSHE and 8.4×10-6 Acm-2, respectively.

  9. On the Novel Biaxial Strain Relaxation Mechanism in Epitaxial Composition Graded La1−xSrxMnO3 Thin Film Synthesized by RF Magnetron Sputtering

    Directory of Open Access Journals (Sweden)

    Yishu Wang

    2015-11-01

    Full Text Available We report on a novel method to fabricate composition gradient, epitaxial La1−xSrxMnO3 thin films with the objective to alleviate biaxial film strain. In this work, epitaxial, composition gradient La1−xSrxMnO3, and pure LaMnO3 and La0.67Sr0.33MnO3 thin films were deposited by radio frequency (RF magnetron sputtering. The crystalline and epitaxy of all films were first studied by symmetric θ–2θ X-ray diffraction (XRD and low angle XRD experiments. Detailed microstructural characterization across the film thickness was conducted by high-resolution transmission electron microscopy and electron diffraction. Four compositional gradient domains were observed in the La1−xSrxMnO3 film ranging from LaMnO3 rich to La0.67Sr0.33MnO3 at the surface. A continuous reduction in the lattice parameter was observed accompanied by a significant reduction in the out-of-plane strain in the film. Fabrication of the composition gradient La1−xSrxMnO3 thin film was found to be a powerful method to relieve biaxial strain under critical thickness. Besides, the coexistence of domains with a composition variance is opening up various new possibilities of designing new nanoscale structures with unusual cross coupled properties.

  10. High energy x-ray diffraction/x-ray fluorescence spectroscopy for high-throughput analysis of composition spread thin films.

    Science.gov (United States)

    Gregoire, John M; Dale, Darren; Kazimirov, Alexander; DiSalvo, Francis J; van Dover, R Bruce

    2009-12-01

    High-throughput crystallography is an important tool in materials research, particularly for the rapid assessment of structure-property relationships. We present a technique for simultaneous acquisition of diffraction images and fluorescence spectra on a continuous composition spread thin film using a 60 keV x-ray source. Subsequent noninteractive data processing provides maps of the diffraction profiles, thin film fiber texture, and composition. Even for highly textured films, our diffraction technique provides detection of diffraction from each family of Bragg reflections, which affords direct comparison of the measured profiles with powder patterns of known phases. These techniques are important for high throughput combinatorial studies as they provide structure and composition maps which may be correlated with performance trends within an inorganic library.

  11. Investigation of the shear thinning behavior of epoxy resins for utilization in vibration assisted liquid composite molding processes

    Science.gov (United States)

    Meier, R.; Kirdar, C.; Rudolph, N.; Zaremba, S.; Drechsler, K.

    2014-05-01

    Efficient production and consumption of energy are of greatest importance for contemporary industries and their products. This has led to an increasing application of lightweight materials in general and of Carbon Fiber Reinforced Plastics (CFRP) in particular. However, broader application of CFRP is often limited by high costs and manual labor production processes. These constraints are addressed by Liquid Composite Molding (LCM) processes. In LCM a dry fibrous preform is placed into a cavity and infiltrated mostly by thermoset resins; epoxy resins are wide spread in CFRP applications. One crucial parameter for a fast mold filling is the viscosity of the resin, which is affected by the applied shear rates as well as temperature and curing time. The work presented focuses on the characterization of the shear thinning behavior of epoxy resins. Furthermore, the correlation with the conditions in vibration assisted LCM processes, where additional shear rates are created during manufacture, is discussed. Higher shear rates result from high frequencies and/or high amplitudes of the vibration motions which are created by a vibration engine mounted on the mold. In rheological investigations the shear thinning behavior of a representative epoxy resin is studied by means of rotational and oscillatory experiments. Moreover, possible effects of shear rates on the chemical curing reaction are studied. Here, the time for gelation is measured for different levels of shear rates in a pre-shearing phase. Based on the rheological studies, the beneficial effect of vibration assistance in LCM processes with respect to mold filling can further be predicted and utilized.

  12. Enhanced tunability of the composition in silicon oxynitride thin films by the reactive gas pulsing process

    Science.gov (United States)

    Aubry, Eric; Weber, Sylvain; Billard, Alain; Martin, Nicolas

    2014-01-01

    Silicon oxynitride thin films were sputter deposited by the reactive gas pulsing process. Pure silicon target was sputtered in Ar, N2 and O2 mixture atmosphere. Oxygen gas was periodically and solely introduced using exponential signals. In order to vary the injected O2 quantity in the deposition chamber during one pulse at constant injection time (TON), the tau mounting time τmou of the exponential signals was systematically changed for each deposition. Taking into account the real-time measurements of the discharge voltage and the I(O*)/I(Ar*) emission lines ratio, it is shown that the oscillations of the discharge voltage during the TON and TOFF times (injection of O2 stopped) are attributed to the preferential adsorption of the oxygen compared to that of the nitrogen. The sputtering mode alternates from a fully nitrided mode (TOFF time) to a mixed mode (nitrided and oxidized mode) during the TON time. For the highest injected O2 quantities, the mixed mode tends toward a fully oxidized mode due to an increase of the trapped oxygen on the target. The oxygen (nitrogen) concentration in the SiOxNy films similarly (inversely) varies as the oxygen is trapped. Moreover, measurements of the contamination speed of the Si target surface are connected to different behaviors of the process. At low injected O2 quantities, the nitrided mode predominates over the oxidized one during the TON time. It leads to the formation of Si3N4-yOy-like films. Inversely, the mixed mode takes place for high injected O2 quantities and the oxidized mode prevails against the nitrided one producing SiO2-xNx-like films.

  13. Ultra-thin film composite mixed matrix membranes incorporating iron(iii)-dopamine nanoparticles for CO2 separation

    Science.gov (United States)

    Kim, Jinguk; Fu, Qiang; Scofield, Joel M. P.; Kentish, Sandra E.; Qiao, Greg G.

    2016-04-01

    Iron dopamine nanoparticles (FeDA NPs) are incorporated into a nanoscale thick polyethylene glycol (PEG) matrix for the first time, to form ultra-thin film composite mixed matrix membranes (UTFC-MMMs) via a recently developed continuous assembly of polymers (CAP) nanotechnology. The FeDA NPs are prepared by in situ nano-complexation between Fe3+ and DA and have a particle size that can be varied from 3 to 74 nanometers by adjusting the molar ratio of DA to Fe3+ ion. The cross-linked selective layer with sub 100 nanometer thickness is prepared by atom transfer radical polymerisation of a mixture of PEG macrocross-linkers and FeDA NPs on top of a highly permeable poly(dimethyl siloxane) (PDMS) prelayer, which is spin-coated onto a porous polyacrylonitrile (PAN) substrate. The incorporation of the FeDA NPs within the PEG-based selective layer is confirmed by XPS analysis. The UTFC-MMMs (thickness: ~45 nm) formed present excellent gas separation performance with a CO2 permeance of ~1200 GPU (1 GPU = 10-6 cm3 (STP) cm-2 s-1 cmHg-1) and an enhanced CO2/N2 selectivity of over 35, which is the best performance for UTFC membranes in the reported literature.Iron dopamine nanoparticles (FeDA NPs) are incorporated into a nanoscale thick polyethylene glycol (PEG) matrix for the first time, to form ultra-thin film composite mixed matrix membranes (UTFC-MMMs) via a recently developed continuous assembly of polymers (CAP) nanotechnology. The FeDA NPs are prepared by in situ nano-complexation between Fe3+ and DA and have a particle size that can be varied from 3 to 74 nanometers by adjusting the molar ratio of DA to Fe3+ ion. The cross-linked selective layer with sub 100 nanometer thickness is prepared by atom transfer radical polymerisation of a mixture of PEG macrocross-linkers and FeDA NPs on top of a highly permeable poly(dimethyl siloxane) (PDMS) prelayer, which is spin-coated onto a porous polyacrylonitrile (PAN) substrate. The incorporation of the FeDA NPs within the PEG

  14. Dye sensitized solar cell applications of CdTiO{sub 3}–TiO{sub 2} composite thin films deposited from single molecular complex

    Energy Technology Data Exchange (ETDEWEB)

    Ehsan, Muhammad Ali [Nanotechnology and Catalysis Centre (NANOCAT), University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Khaledi, Hamid [Department of Chemistry, Faculty of Science, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Pandikumar, Alagarsamy; Huang, Nay Ming [Department of Physics, Faculty of Science, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Arifin, Zainudin [Department of Chemistry, Faculty of Science, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Mazhar, Muhammad, E-mail: mazhar42pk@yahoo.com [Department of Chemistry, Faculty of Science, University of Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)

    2015-10-15

    A heterobimetallic complex [Cd{sub 2}Ti{sub 4}(μ-O){sub 6}(TFA){sub 8}(THF){sub 6}]·1.5THF (1) (TFA=trifluoroacetato, THF=tetrahydrofuran) comprising of Cd:Ti (1:2) ratio was synthesized by a chemical reaction of cadmium (II) acetate with titanium (IV) isopropoxide and triflouroacetic acid in THF. The stoichiometry of (1) was recognized by single crystal X-ray diffraction, spectroscopic and elemental analyses. Thermal studies revealed that (1) neatly decomposes at 450 °C to furnish 1:1 ratio of cadmium titanate:titania composite oxides material. The thin films of CdTiO{sub 3}–TiO{sub 2} composite oxides were deposited at 550 °C on fluorine doped tin oxide coated conducting glass substrate in air ambient. The micro-structure, crystallinity, phase identification and chemical composition of microspherical architectured CdTiO{sub 3}–TiO{sub 2} composite thin film have been determined by scanning electron microscopy, X-ray diffraction, Raman spectroscopy and energy dispersive X-ray analysis. The scope of composite thin film having band gap of 3.1 eV was explored as photoanode for dye-sensitized solar cell application. - Graphical abstarct: Microspherical designed CdTiO{sub 3}–TiO{sub 2} composite oxides photoanode film has been fabricated from single source precursor [Cd{sub 2}Ti{sub 4}(μ-O){sub 6}(TFA){sub 8}(THF){sub 6}]·1.5THF via aerosol assisted chemical vapor deposition technique for dye sensitized solar cell application. - Highlights: • Synthesis and characterization of a heterobimetallic Cd–Ti complex. • Fabrication of CdTiO{sub 3}–TiO{sub 2} thin film photoelectrode. • Application as dye sensitized photoanode for solar application.

  15. One-dimensional semiconductor nanostructure based thin-film partial composite formed by transfer implantation for high-performance flexible and printable electronics at low temperature.

    Science.gov (United States)

    Moon, Kyeong-Ju; Lee, Tae-Il; Choi, Ji-Hyuk; Jeon, Joohee; Kang, Youn Hee; Kar, Jyoti Prakash; Kang, Jung Han; Yun, Ilgu; Myoung, Jae-Min

    2011-01-25

    Having high bending stability and effective gate coupling, the one-dimensional semiconductor nanostructures (ODSNs)-based thin-film partial composite was demonstrated, and its feasibility was confirmed through fabricating the Si NW thin-film partial composite on the poly(4-vinylphenol) (PVP) layer, obtaining uniform and high-performance flexible field-effect transistors (FETs). With the thin-film partial composite optimized by controlling the key steps consisting of the two-dimensional random dispersion on the hydrophilic substrate of ODSNs and the pressure-induced transfer implantation of them into the uncured thin dielectric polymer layer, the multinanowire (NW) FET devices were simply fabricated. As the NW density increases, the on-current of NW FETs increases linearly, implying that uniform NW distribution can be obtained with random directions over the entire region of the substrate despite the simplicity of the drop-casting method. The implantation of NWs by mechanical transfer printing onto the PVP layer enhanced the gate coupling and bending stability. As a result, the enhancements of the field-effect mobility and subthreshold swing and the stable device operation up to a 2.5 mm radius bending situation were achieved without an additional top passivation.

  16. Flexible Sensing Arrays Fabricated with Carbon Nanofiber Composite Thin Films for Posture Monitoring

    Science.gov (United States)

    Chang, Fuh-Yu; Wang, Ruoh-Huey; Lin, Yu-Hsien; Chen, Tse-Min; Lee, Yueh-Feng; Huang, Shu-Jiuan; Liu, Chia-Ming

    2011-06-01

    Faulty posture increases joint stress and causes postural pain syndrome. In this paper, we present a portable strain sensing system with flexible sensor arrays to warn patients to correct inappropriate posture. A 3×3 flexible strain sensing array system was fabricated using patterned surface treatment and the tilted-drop process with carbon nanofiber composite solutions on polyimide substrates. Atmospheric plasma was used to enhance or reduce the surface energy in specific areas for patterned surface treatment. A scanning circuit was also developed to capture the signal from the flexible sensing array. The developed system has been used to measure the bent angle of the human neck from 15 to 60°. The results indicate that human posture can be successfully captured by analyzing the measured strains from a flexible strain sensing array.

  17. Nano-mechanical properties of nano-gold/DLC composite thin films

    Science.gov (United States)

    Paul, Rajib; Bhadra, Nilanjana; Mukhopadhyay, Anup Kumar; Bhar, Radhaballav; Pal, Arun Kumar

    2014-11-01

    Diamond-like-Carbon composite films, with embedded gold nanoparticles, were deposited onto glass substrates by using capacitively coupled plasma chemical vapour deposition (CCP-CVD) technique. The volume fraction of the metal nanoparticles in the films as well as the size of the nanoparticles was varied by varying the percentage of argon in the methane + argon mixture during the deposition. Bonding environments in these films were obtained from Raman and GIXRD. The nanomechanical and nanotribological properties of the Au-DLC nanocomposite films were evaluated. In situ SPM imaging was utilized to depict deformation characteristics developed during the static and dynamic contact events. Influence of metal incorporation on the extent of sp2/sp3 hybridization and thereby on the nanomechanical and nanotribological properties of the DLC films was studied.

  18. Structural, compositional and morphological studies of thermally evaporated MoO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Senthilkumar, R., E-mail: raviganesa@rediffmail.com, E-mail: gravicrc@gmail.com; Ravi, G., E-mail: raviganesa@rediffmail.com, E-mail: gravicrc@gmail.com [Department of Physics, Alagappa University, Karaikudi - 630003 (India)

    2014-04-24

    Molybdenum oxide (MoO{sub 3}) nanostructures were grown on different substrates such as glass, indium tin oxide coated glass and fluorine doped glass by thermal evaporation of MoO{sub 3} powder at elevated temperature (750°C) using tube furnace without any catalyst and then by subsequent O{sub 2}/Ar flow rate. The morphology, composition and crystal structure were examined by using SEM, EDAX, Laser Raman and XRD. The films are polycrystalline with well-defined diffraction peaks and it consist of MoO{sub 3} with α-orthorhombic structure. The synthesized MoO{sub 3} belongs to different morphologies, generally nanobelt and nanohunk structures. The EDAX spectra confirm the films are composed only of Mo and O atoms. The O/Mo ratio is nearly equal to 3 that shows the stoichiometry of MoO{sub 3}.

  19. On the Definition of Effective Permittivity and Permeability For Thin Composite Layers

    CERN Document Server

    Saenz, E; Ikonen, P; Tretyakov, S; Gonzalo, Ramon; Ikonen, Pekka; Saenz, Elena; Tretyakov, Sergei

    2007-01-01

    The problem of definition of effective material parameters (permittivity and permeability) for composite layers containing only one-two parallel arrays of complex-shaped inclusions is discussed. Such structures are of high importance for the design of novel metamaterials, where the realizable layers quite often have only one or two layers of particles across the sample thickness. Effective parameters which describe the averaged induced polarizations are introduced. As an explicit example, we develop an analytical model suitable for calculation of the effective material parameters $\\epsilon_{\\rm{eff}}$ and $\\mu_{\\rm{eff}}$ for double arrays of electrically small electrically polarizable scatterers. Electric and magnetic dipole moments induced in the structure and the corresponding reflection and transmission coefficients are calculated using the local field approach for the normal plane-wave incidence, and effective parameters are introduced through the averaged fields and polarizations. In the absence of loss...

  20. Vibration, Stability, and Resonance of Angle-Ply Composite Laminated Rectangular Thin Plate under Multiexcitations

    Directory of Open Access Journals (Sweden)

    M. Sayed

    2013-01-01

    Full Text Available An analytical investigation of the nonlinear vibration of a symmetric cross-ply composite laminated piezoelectric rectangular plate under parametric and external excitations is presented. The method of multiple time scale perturbation is applied to solve the nonlinear differential equations describing the system up to and including the second-order approximation. All possible resonance cases are extracted at this approximation order. The case of 1 : 1 : 3 primary and internal resonance, where Ω3≅ω1, ω2≅ω1, and ω3≅3ω1, is considered. The stability of the system is investigated using both phase-plane method and frequency response curves. The influences of the cubic terms on nonlinear dynamic characteristics of the composite laminated piezoelectric rectangular plate are studied. The analytical results given by the method of multiple time scale is verified by comparison with results from numerical integration of the modal equations. Reliability of the obtained results is verified by comparison between the finite difference method (FDM and Runge-Kutta method (RKM. It is quite clear that some of the simultaneous resonance cases are undesirable in the design of such system. Such cases should be avoided as working conditions for the system. Variation of the parameters μ1, μ2, α7,β8, ω1, ω2, f1, f2 leads to multivalued amplitudes and hence to jump phenomena. Some recommendations regarding the different parameters of the system are reported. Comparison with the available published work is reported.

  1. Synthesis and characterization of ZnO:TiO{sub 2} nano composites thin films deposited on glass substrate by sol-gel spray coating technique

    Energy Technology Data Exchange (ETDEWEB)

    Sutanto, Heri, E-mail: herisutanto@undip.ac.id; Nurhasanah, Iis; Hidayanto, Eko; Wibowo, Singgih [Department of Physics, Faculty of Natural Sciences and Mathematics, Diponegoro University (Indonesia); Hadiyanto [Department of Chemical Engineering, Faculty of Engineering, Diponegoro University (Indonesia)

    2015-12-29

    In this work, (ZnO){sub x}:(TiO{sub 2}){sub 1-x} nano composites thin films, with x = 1, 0.75, 0.5, 0.25, and 0, have been prepared by sol–gel spray coating technique onto glass substrate. Pure TiO{sub 2} and ZnO thin films were synthesized from titanium isopropoxide-based and zinc acetate-based precursor solutions, respectively, whereas the composite films were obtained from the mixture of these solutions at the specific % vol ratios. The properties and performance of nano composite ZnO, TiO{sub 2} and ZnO:TiO{sub 2} thin films at different composition have been investigated. Ultraviolet – Visible (UV-Vis) Spectrophotometer and Scanning Electron Microscopy (SEM) were employed in order to get morphology and transmittance of thin films. Testing the ability of photocatalytic activity of obtained films was conducted on photodegradation of methylene blue (MB) dye and organic pollutants of wastewater under a 30 watt UV light irradiation, then testing BOD, COD and TPC were conducted. Using the Tauc model, the band-gap energy decreased from 3.12 eV to 3.02 eV for the sample with x = 1 and 0, respectively. This decrease occured along with the replacement of percentage of ZnO by TiO{sub 2} on the films. This decrease also reduced the minimum energy that required for electron excitation. Obtained thin films had nanoscale roughness level with range 3.64 to 17.30 nm. The film with x= 0 has the biggest removal percentage on BOD, COD and TPC mesurements with percentage 54.82%, 62.73% and 99.88%, respectively.

  2. Synthesis and characterization of ZnO:TiO2 nano composites thin films deposited on glass substrate by sol-gel spray coating technique

    Science.gov (United States)

    Sutanto, Heri; Nurhasanah, Iis; Hidayanto, Eko; Wibowo, Singgih; Hadiyanto

    2015-12-01

    In this work, (ZnO)x:(TiO2)1-x nano composites thin films, with x = 1, 0.75, 0.5, 0.25, and 0, have been prepared by sol-gel spray coating technique onto glass substrate. Pure TiO2 and ZnO thin films were synthesized from titanium isopropoxide-based and zinc acetate-based precursor solutions, respectively, whereas the composite films were obtained from the mixture of these solutions at the specific % vol ratios. The properties and performance of nano composite ZnO, TiO2 and ZnO:TiO2 thin films at different composition have been investigated. Ultraviolet - Visible (UV-Vis) Spectrophotometer and Scanning Electron Microscopy (SEM) were employed in order to get morphology and transmittance of thin films. Testing the ability of photocatalytic activity of obtained films was conducted on photodegradation of methylene blue (MB) dye and organic pollutants of wastewater under a 30 watt UV light irradiation, then testing BOD, COD and TPC were conducted. Using the Tauc model, the band-gap energy decreased from 3.12 eV to 3.02 eV for the sample with x = 1 and 0, respectively. This decrease occured along with the replacement of percentage of ZnO by TiO2 on the films. This decrease also reduced the minimum energy that required for electron excitation. Obtained thin films had nanoscale roughness level with range 3.64 to 17.30 nm. The film with x= 0 has the biggest removal percentage on BOD, COD and TPC mesurements with percentage 54.82%, 62.73% and 99.88%, respectively.

  3. Inkjet printing of multi-walled carbon nanotube/polymer composite thin film for interconnection.

    Science.gov (United States)

    Lok, Boon Keng; Ng, You Min; Liang, Yen Nan; Hu, Xiao

    2010-07-01

    In this paper, multi-walled carbon nanotube (MWCNT) ink was selectively patterned by inkjet printing on substrates to form conductive traces and electrodes for interconnection application. MWCNT was firstly functionalized using concentrated acid and dispersed in deionized water to form a colloidal solution. Various concentrations of MWCNT were formulated to test the stability of the solution. The printability of the MWCNT ink was examined against printing temperature, ink concentration and ink droplet pitch. Rheological properties of the ink were determined by rheometer and sessile drop method. The electrical conductivity of the MWCNT pattern was measured against multiple printing of MWCNT on the same pattern (up to 10 layers). While single layer printing pattern exhibited highest resistance, the CNT entangled together and formed a random network with more printed layers has higher conductivity. The electrical properties of the printed film was compared to a composite ink of CNT and conducting polymer (CNT ink was mixed with conductive polymer solution, Poly(3,4-ethylenedioxythiophene)-Poly(styrenesulfonate) (PEDOT:PSS)). Scanning electron microscopy (SEM) was used to observe the surface structure and atomic force microscopy (AFM) was used to study the morphology of the printed film under different conditions.

  4. Exchange bias in zinc ferrite-FeNiMoB based metallic glass composite thin films

    Energy Technology Data Exchange (ETDEWEB)

    R, Lisha; P, Geetha; B, Aravind P.; Anantharaman, M. R., E-mail: mraiyer@yahoo.com [Cochin University of Science and Technology, Cochin-682022 (India); T, Hysen [Christian College, Chengannur, Kerala-689121 (India); Ojha, S.; Avasthi, D. K. [Inter University Accelerator Centre, Vasant Kunj, New Delhi-110067 (India); Ramanujan, R. V. [School of Materials Science and Engineering, Nanyang Technological University (Singapore)

    2015-06-24

    The Exchange bias phenomenon and methods to manipulate the bias field in a controlled manner are thrust areas in magnetism due to its sophisticated theoretical concepts as well as advanced technological utility in the field of spintronics. The Exchange bias effect is observed as a result of ferromagnetic-antiferromagnetic (FM-AFM) exchange interaction, usually observed as a loop shift on field cooling below the Neel temperature of AFM. In the present study, we have chosen zinc ferrite which is a well known antiferromagnet, and FeNiMoB based metallic glass as the ferromagnet. The films were prepared by RF sputtering technique. The thickness and composition was obtained by RBS. The magnetic studies using SQUID VSM indicate exchange bias effect in the system. The effect of thermal annealing on exchange bias effect was studied. The observed exchange bias in the zinc ferrite-FeNiMoB system is not due to FM-AFM coupling but due to spin glass-ferromagnetic interaction.

  5. Impact of the cation composition on the electrical performance of solution-processed zinc tin oxide thin-film transistors.

    Science.gov (United States)

    Kim, Yoon Jang; Oh, Seungha; Yang, Bong Seob; Han, Sang Jin; Lee, Hong Woo; Kim, Hyuk Jin; Jeong, Jae Kyeong; Hwang, Cheol Seong; Kim, Hyeong Joon

    2014-08-27

    This study examined the structural, chemical, and electrical properties of solution-processed (Zn,Sn)O3 (ZTO) films with various Sn/[Zn+Sn] ratios for potential applications to large-area flat panel displays. ZTO films with a Zn-rich composition had a polycrystalline wurtzite structure. On the other hand, the Sn-rich ZTO films exhibited a rutile structure, where the Zn atom was speculated to replace the Sn site, thereby acting as an acceptor. In the intermediate composition regions (Sn/[Zn+Sn] ratio from 0.28 to 0.48), the ZTO films had an amorphous structure, even after annealing at 450 °C. The electrical transport properties and photobias stability of ZTO thin film transistors (TFTs) were also examined according to the Sn/[Zn+Sn] ratio. The optimal transport property of ZTO TFT was observed for the device with an amorphous structure at a Sn/[Zn+Sn] ratio of 0.48. The mobility, threshold voltage, subthreshold swing, and on/off current ratio were 4.3 cm(2)/(V s), 0 V, 0.4 V/decade, and 4.1 × 10(7), respectively. In contrast, the device performance for the ZTO TFTs with either a higher or lower Sn concentration suffered from low mobility and a high off-state current, respectively. The photoelectrical stress measurements showed that the photobias stability of the ZTO TFTs was improved substantially when the ZTO semiconducting films had a lower oxygen vacancy concentration and an amorphous structure. The relevant rationale is discussed based on the phototransition and subsequent migration mechanism from neutral to positively charged oxygen vacancies.

  6. Swift heavy ion irradiation induced phase transformation in undoped and niobium doped titanium dioxide composite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, Subodh K., E-mail: subodhkgtm@gmail.com [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India); Chettah, Abdelhak [LGMM Laboratory, Université 20 Août 1955-Skikda, BP 26, 21000 Skikda (Algeria); Singh, R.G. [Department of Physics, Bhagini Nivedita College, Delhi University, Delhi 110043 (India); Ojha, Sunil; Singh, Fouran [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

    2016-07-15

    Study reports the effect of swift heavy ion (SHI) irradiation induced phase transformation in undoped and Niobium doped anatase TiO{sub 2} composite thin films. Investigations were carried out at different densities of electronic excitations (EEs) using 120 MeV Ag and 130 MeV Ni ions irradiations. Films were initially annealed at 900 °C and results revealed that undoped films were highly stable in anatase phase, while the Nb doped films showed the composite nature with the weak presence of Niobium penta-oxide (Nb{sub 2}O{sub 5}) phase. The effect at low density of EEs in undoped film show partial anatase to rutile phase transformation; however doped film shows only further growth of Nb{sub 2}O{sub 5} phase beside the anatase to rutile phase transformation. At higher density of EEs induced by Ag ions, registered continuous ion track of ∼3 nm in lattice which leads to nano-crystallization followed by decomposition/amorphization of rutile TiO{sub 2} and Nb{sub 2}O{sub 5} phases in undoped and doped films, respectively. However, Ni ions are only induced discontinuous sequence of ion tracks with creation of damage and disorder and do not show amorphization in the lattice. The in-elastic thermal spike calculations were carried out for anatase TiO{sub 2} phase to understand the effect of EEs on anatase to rutile phase transformation followed by amorphization in NTO films in terms of continuous and discontinuous track formation by SHI irradiation.

  7. Enzymatic cleaning of biofouled thin-film composite reverse osmosis (RO) membrane operated in a biofilm membrane reactor.

    Science.gov (United States)

    Khan, Mohiuddin; Danielsen, Steffen; Johansen, Katja; Lorenz, Lindsey; Nelson, Sara; Camper, Anne

    2014-02-01

    Application of environmentally friendly enzymes to remove thin-film composite (TFC) reverse osmosis (RO) membrane biofoulants without changing the physico-chemical properties of the RO surface is a challenging and new concept. Eight enzymes from Novozyme A/S were tested using a commercially available biofouling-resistant TFC polyamide RO membrane (BW30, FilmTech Corporation, Dow Chemical Co.) without filtration in a rotating disk reactor system operated for 58 days. At the end of the operation, the accumulated biofoulants on the TFC RO surfaces were treated with the three best enzymes, Subtilisin protease and lipase; dextranase; and polygalacturonase (PG) based enzymes, at neutral pH (~7) and doses of 50, 100, and 150 ppm. Contact times were 18 and 36 h. Live/dead staining, epifluorescence microscopy measurements, and 5 μm thick cryo-sections of enzyme and physically treated biofouled membranes revealed that Subtilisin protease- and lipase-based enzymes at 100 ppm and 18 h contact time were optimal for removing most of the cells and proteins from the RO surface. Culturable cells inside the biofilm declined by more than five logs even at the lower dose (50 ppm) and shorter incubation period (18 h). Subtilisin protease- and lipase-based enzyme cleaning at 100 ppm and for 18 h contact time restored the hydrophobicity of the TFC RO surface to its virgin condition while physical cleaning alone resulted in a 50° increase in hydrophobicity. Moreover, at this optimum working condition, the Subtilisin protease- and lipase-based enzyme treatment of biofouled RO surface also restored the surface roughness measured with atomic force microscopy and the mass percentage of the chemical compositions on the TFC surface estimated with X-ray photoelectron spectroscopy to its virgin condition. This novel study will encourage the further development and application of enzymes to remove biofoulants on the RO surface without changing its surface properties.

  8. Application of thin film composite membranes with forward osmosis technology for the separation of emulsified oil-water

    KAUST Repository

    Duong, Hoang Hanh Phuoc

    2014-02-01

    Large amounts of oily wastewater have been produced from various industries. The main challenge of oily wastewater treatments is to separate the stable emulsified oil particles from water. Therefore, the aim of this study is to investigate the effectiveness of forward osmosis (FO) processes to treat the stable oil-water emulsions. The FO technique has been demonstrated successfully for the treatment of a wide range of oil-water emulsions from a low to a very high concentration up to 200,000. ppm. The dependence of separation performance on oily feed concentration and flow rate has been investigated. Water can be separated from oily feeds containing 500. ppm or 200,000. ppm emulsified oil at a relatively high flux of 16.5±1.2. LMH or 11.8±1.6. LMH respectively by using a thin film composite membrane PAN-TFC and 1. M NaCl as the draw solution. Moreover, this membrane can achieve an oil rejection of 99.88% to produce water with a negligible oil level. Due to the presence of emulsified oil particles in the oily feed solutions, the membrane fouling has been addressed in this study. Better anti-fouling TFC FO membranes are needed. © 2013 Elsevier B.V.

  9. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation.

    Science.gov (United States)

    Ben-Sasson, Moshe; Lu, Xinglin; Bar-Zeev, Edo; Zodrow, Katherine R; Nejati, Siamak; Qi, Genggeng; Giannelis, Emmanuel P; Elimelech, Menachem

    2014-10-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Compositional dependence of the optical properties of amorphous semiconducting glass Ge10AsxSe(90-x) thin films

    Science.gov (United States)

    Shaaban, E. R.

    2007-03-01

    Optical properties of ternary chalcognide amorphous Ge10AsxSe(90-x) (with 10⩽x⩽25 at%) thin films prepared by thermal evaporation have been measured in visible and near-infrared spectral region. The straightforward analysis proposed by Swanepoel has been successfully employed, and it has allowed us to determine the average thickness d¯, and the refractive index, n, of the films, with high accuracy. The refractive index, n and the average thickness d¯ has been determined from the upper and lower envelopes of the transmission spectra measured at normal incidence, in the spectral range 400 2500 nm. The absorption coefficient α, and therefore extinction coefficient k, have been determined from the transmission spectra in the strong-absorption region. The dispersion of the refractive index is discussed in terms of the single oscillator Wemple DiDomenico model, and the optical absorption edge is described using the ‘nondirect transition’ model proposed by Tauc. Likewise, the optical energy gap is derived from Tauc's extrapolation. The relationship between the optical gap and chemical composition in Ge10AsxSe(90-x) amorphous system is discussed in terms of the average heat of atomization Hs and average coordination number Nc. Finally, the chemical bond approach has been also applied successfully to interpret the decrease of the glass optical gap with increasing As content.

  11. Compositional dependence of the optical constants of amorphous GexAs20Se80-x thin films

    Science.gov (United States)

    Dahshan, A.; Amer, H. H.; Aly, K. A.

    2008-11-01

    This paper reports the effect of replacement of selenium by germanium on the optical constants of chalcogenide GexAs20Se80-x (where x = 0, 5, 10, 15 and 20 at.%) thin films. Films of GexAs20Se80-x glasses were prepared by thermal evaporation of the bulk samples. The transmission spectra, T(λ), of the films at normal incidence were obtained in the spectral region from 400 to 2500 nm. A straightforward analysis proposed by Swanepoel, based on the use of the maxima and minima of the interference fringes, has been applied to derive the real and imaginary parts of the complex index of refraction and also the film thickness. Increasing germanium content is found to affect the refractive index and the extinction coefficient of the GexAs20Se80-x films. Optical absorption measurements show that the fundamental absorption edge is a function of composition. With increasing germanium content the refractive index decreases while the optical band gap increases.

  12. Design and fabrication of inner-selective thin-film composite (TFC) hollow fiber modules for pressure retarded osmosis (PRO)

    KAUST Repository

    Wan, Chun Feng

    2016-08-03

    Pressure retarded osmosis (PRO) is a promising technology to harvest the renewable osmotic energy from salinity gradients. There are great progresses in the fabrication of PRO membranes in the last decade. Thin-film composite (TFC) hollow fibers have been widely studied and demonstrated superior performance. However, the lack of effective TFC hollow fiber modules hinders the commercialization of the PRO technology. Knowledge and experiences to fabricate TFC hollow fiber modules remain limited in the open literature. In this study, we aim to reveal the engineering and science on how to fabricate TFC hollow fiber modules including the formation of inner-selective polyamide layers and the repair of leakages. TFC-PES hollow fiber modules with 30% and 50% packing densities have been successfully fabricated, showing peak power densities of 20.0 W/m2 and 19.4 W/m2, respectively, at 20 bar using 1 M NaCl solution and DI water as feeds. The modules may be damaged during handling and high pressure testing. The repaired modules have a power density of 18.2 W/m2, 91% of the power densities of the undamaged ones. This study would make up the gap between TFC membrane fabrication and TFC membrane module fabrication in the membrane industry. © 2016 Elsevier B.V.

  13. Solvothermal synthesis of nanoporous TiO2: the impact on thin-film composite membranes for engineered osmosis application

    Science.gov (United States)

    Emadzadeh, D.; Ghanbari, M.; Lau, W. J.; Rahbari-Sisakht, M.; Matsuura, T.; Ismail, A. F.; Kruczek, B.

    2016-08-01

    In the current study, the impact of self-synthesized nanoporous titanium oxide (NT) on the morphology, performance and fouling of a polyamide (PA) thin-film composite (TFC) membrane was investigated when the membrane was applied for engineering osmosis (EO). The nanoporous structure and the spindle-like shape of NT were revealed through transmission electron microscopy (TEM), while the AATPS modification of NT was verified by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The results of x-ray photoelectron spectroscopy (XPS) and x-ray diffraction (XRD) confirmed the presence of modified NT (mNT) in the PA dense active layer of the TFC membrane. The outgrowth of the ‘leaf-like’ structure, upon mNT loading, at the surface of the PA layer was observed by field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The TFC membrane prepared with 0.05 wt% mNT loading in the organic phase showed the water flux of 26.4 l m-2 h-1 when tested in the forward osmosis (FO) mode using 0.5M and 10 mM NaCl solution as the draw and feed solution, respectively. Moreover, the TFC-mNT membrane also demonstrated an intensified antifouling property against organic foulant during FO application and it was possible to retrieve the initial water flux almost completely with a simple water-rinsing process.

  14. Effect of Blend Composition and Additives on the Morphology of PCPDTBT:PC71BM Thin Films for Organic Photovoltaics.

    Science.gov (United States)

    Schaffer, Christoph J; Schlipf, Johannes; Dwi Indari, Efi; Su, Bo; Bernstorff, Sigrid; Müller-Buschbaum, Peter

    2015-09-30

    The use of solvent additives in the fabrication of bulk heterojunction polymer:fullerene solar cells allows to boost efficiencies in several low bandgap polymeric systems. It is known that solvent additives tune the nanometer scale morphology of the bulk heterojunction. The full mechanism of efficiency improvement is, however, not completely understood. In this work, we investigate the influences of blend composition and the addition of 3 vol % 1,8-octanedithiol (ODT) as solvent additive on polymer crystallization and both, vertical and lateral morphologies of poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] and [6,6]-phenyl C71-butyric acid methyl ester (PCPDTBT:PC71BM) blend thin films processed from chlorobenzene-based solutions. The nanoscale morphology is probed with grazing incidence small- and wide-angle X-ray scattering as well as X-ray reflectivity and complemented with UV/vis spectroscopy. In PCPDTBT:PC71BM films the use of ODT is found to lower the solubility of fullerene in the polymer matrix and to promote polymer crystallization, both vertical and lateral microphase separation with morphological coarsening, and formation of a fullerene-rich topping layer. The enhanced photovoltaic performance is explained by these findings.

  15. Temperature effect on buckling properties of ultra-thin-walled lenticular collapsible composite tube subjected to axial compression

    Institute of Scientific and Technical Information of China (English)

    Bai Jiangbo; Xiong Junjiang

    2014-01-01

    This paper seeks to outline the temperature effect on the buckling properties of ultra-thin-walled lenticular collapsible composite tube (LCCT) subjected to axial compression. The buckling tests of the LCCT specimens subjected to axial compression were carried out on INSTRON-500N servo-hydraulic machine in dry state and at the temperatures of 25 ?C, 100 ?C and ?80 ?C. The load-displacement curves and buckling initiation loads were measured and the buckling initiation mechanism was discussed from experimental observations. Experiments show that the buckling initiation load, on average, is only about 2.2% greater at the low temperature of ?80 ?C than at the room temperature of 25 ?C due to the material hardening, demonstrating an insignificant increase in the buckling initiation load, whereas it is about 19.5%lower at the high temperature of 100 ?C than at the room temperature owing to the material softening, implying a significant decrease in the buckling initiation load. The failure mode of the LCCT in axial compres-sion tests at three different temperatures can be reckoned to be characteristic of the buckling initi-ation and propagation around the central region until rupture. The finite element (FE) model is presented to simulate the buckling initiation mechanism based on the eigenvalue-based methodol-ogy. Good correlation between experimental and numerical results is achieved.

  16. Optical and physical properties of different composition of In{sub x}Se{sub 1-x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    El-Kabnay, N. [Physics Department, Assiut University, Assiut (Egypt); Shaaban, E.R. [Physics Department, A1-Azhar University, Assiut (Egypt)], E-mail: esam_ramadan2005@yahoo.com; Afify, N. [Physics Department, Assiut University, Assiut (Egypt); Abou-sehly, A.M. [Physics Department, A1-Azhar University, Assiut (Egypt)

    2008-01-01

    Thin film binary alloys of In{sub x}Se{sub 1-x} (0.05{<=}x{<=}0.30) have been prepared by the thermal evaporation technique. The optical transmission and reflection spectrum of these films were measured in the range 300-1100 nm. Both refractive index, n and extinction coefficient k have been determined from transmission and reflection measurements in terms of Murmann's equations. The dispersion of the refractive index is discussed in terms of the single-oscillator Wemple-DiDomenico model. The width of band tail is determined and the optical absorption edge is described using the 'non-direct transition' model proposed by Tauc. Finally, the relationship between the optical gap and chemical composition in In{sub x}Se{sub 1-x} amorphous system is discussed in terms of the average heat of atomization H{sub s} and average coordination number N{sub c}. The results of these calculations can be used rationalize the observed optical properties of these materials. Finally, the chemical bond approach has been also applied to interpret the decrease of the glass optical gap with increasing In content.

  17. Morphology, composition and electrical properties of SnO{sub 2}:Cl thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Hsyi-En, E-mail: sean@mail.stust.edu.tw; Wen, Chia-Hui; Hsu, Ching-Ming [Department of Electro-Optical Engineering, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan (China)

    2016-01-15

    Chlorine doped SnO{sub 2} thin films were prepared using atomic layer deposition at temperatures between 300 and 450 °C using SnCl{sub 4} and H{sub 2}O as the reactants. Composition, structure, surface morphology, and electrical properties of the as-deposited films were examined. Results showed that the as-deposited SnO{sub 2} films all exhibited rutile structure with [O]/[Sn] ratios between 1.35 and 1.40. The electrical conductivity was found independent on [O]/[Sn] ratio but dependent on chlorine doping concentration, grain size, and surface morphology. The 300 °C-deposited film performed a higher electrical conductivity of 315 S/cm due to its higher chlorine doping level, larger grain size, and smoother film surface. The existence of Sn{sup 2+} oxidation state was demonstrated to minimize the effects of chlorine on raising the electrical conductivity of films.

  18. Structure and composition of zirconium carbide thin-film grown by ion beam sputtering for optical applications

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Amol, E-mail: modimh@rrcat.gov.in; Modi, Mohammed H., E-mail: modimh@rrcat.gov.in; Dhawan, Rajnish, E-mail: modimh@rrcat.gov.in; Lodha, G. S., E-mail: modimh@rrcat.gov.in [X-ray Optics Section, ISU Division, Raja Ramanna Centre for Advanced Technology, Indore-452013 (India)

    2014-04-24

    Thin film of compound material ZrC was deposited on Si (100) wafer using ion beam sputtering method. The deposition was carried out at room temperature and at base pressure of 3×10{sup −5} Pa. X-ray photoelectron spectroscopy (XPS) measurements were performed for determining the surface chemical compositions. Grazing incidence x-ray reflectivity (GIXRR) measurements were performed to study the film thickness, roughness and density. From GIXRR curve roughness value of the film was found less than 1 nm indicating smooth surface morphology. Films density was found 6.51 g/cm{sup 3}, which is close to bulk density. Atomic force microscopy (AFM) measurements were performed to check the surface morphology. AFM investigation showed that the film surface is smooth, which corroborate the GIXRR data. Figure 2 of the original article PDF file, as supplied to AIP Publishing, contained a PDF processing error. This article was updated on 12 May 2014 to correct that error.

  19. Novel cellulose ester substrates for high performance flat-sheet thin-film composite (TFC) forward osmosis (FO) membranes

    KAUST Repository

    Ong, Rui Chin

    2015-01-01

    A novel hydrophilic cellulose ester with a high intrinsic water permeability and a water partition coefficient was discovered to construct membrane supports for flat-sheet thin film composite (TFC) forward osmosis (FO) membranes for water reuse and seawater desalination with high performance. The performance of TFC-FO membranes prepared from the hydrophilic cellulose ester containing a high degree of OH and a moderate degree of Pr substitutions clearly surpasses those prepared from cellulose esters and other polymers with moderate hydrophilicity. Post-treatments of TFC-FO membranes using sodium dodecyl sulfate (SDS) and glycerol followed by heat treatment further enhance the water flux without compromising the selectivity. Positron annihilation lifetime analyses have confirmed that the SDS/glycerol post-treatment increases the free volume size and fractional free volume of the polyamide selective layer. The newly developed post-treated TFC-FO membranes exhibit a remarkably high water flux up to 90 LMH when the selective layer is oriented towards the draw solution (i.e., PRO mode) using 1. M NaCl as the draw solution and DI water as the feed. For seawater desalination, the membranes display a high water flux up to 35 LMH using a 2. M NaCl draw solution. These water fluxes exceeded the water fluxes achieved by other types of FO membranes reported in literatures. © 2014 Elsevier B.V.

  20. In situ formation of silver nanoparticles on thin-film composite reverse osmosis membranes for biofouling mitigation

    KAUST Repository

    Ben-Sasson, Moshe

    2014-10-01

    The potential to incorporate silver nanoparticles (Ag-NPs) as biocides in membranes for water purification has gained much interest in recent years. However, a viable strategy for loading the Ag-NPs on the membrane remains challenging. This paper presents a novel, facile procedure for loading Ag-NPs on thin-film composite (TFC) reverse osmosis membranes. Reaction of silver salt with a reducing agent on the membrane surface resulted in uniform coverage of Ag-NPs, irreversibly bound to the membrane, as confirmed by XPS, TEM, and SEM analyses. Salt selectivity of the membrane as well its surface roughness, hydrophilicity, and zeta potential were not impacted by Ag-NP functionalization, while a slight reduction (up to 17%) in water permeability was observed. The formed Ag-NPs imparted strong antibacterial activity to the membrane, leading to reduction of more than 75% in the number of live bacteria attached to the membrane for three model bacteria strains. In addition, confocal microscopy analyses revealed that Ag-NPs significantly suppressed biofilm formation, with 41% reduction in total biovolume and significant reduction in EPS, dead, and live bacteria on the functionalized membrane. The simplicity of the method, the short reaction time, the ability to load the Ag-NPs on site, and the strong imparted antibacterial activity highlight the potential of this method in real-world RO membrane applications. © 2014 Elsevier Ltd.

  1. Magnetically tunable dielectric, impedance and magnetoelectric response in MnFe2O4/(Pb1-xSrx)TiO3 composites thin films

    Science.gov (United States)

    Bala, Kanchan; Kotnala, R. K.; Negi, N. S.

    2017-02-01

    We have synthesized piezomagnetic-piezoelectric composites thin films MnFe2O4/(Pb1-xSrx)TiO3, where x=0.1, 0.2, and 0.3, using the metalorganic deposition (MOD) reaction method. The structural and microstructural analysis using the X-ray diffraction (XRD), AFM, and SEM reveals the presence of homogenous growth of both pervoskite and spinel phases in the composite films. Our results show that all the composites films exhibit good multiferroic as well as considerable magnetoelectric coupling. The impedance (Z‧ and Z″) and electrical modulus (M‧ and M″) Nyquist plots show distinct electrical responses with the magnetic field. Our analyses suggest that this electrical response arises due to the coexistence of the high resistive phase and the comparatively conductive phase in the MFO/PST composite films. The maximum magnetoelectric coefficient (α) is found to be 4.29 V Oe-1 cm-1 and 2.82 V Oe-1 cm-1 for compositions x=0.1 and 0.2. These values are substantially larger than those reported for bilayer composites thin films in literature and make them interesting for room temperature device applications.

  2. Influence of the Composition on the Thermoelectric and Electro-physical Properties of Ge-Sb-Te Thin Films for Phase Change Memory Application

    Directory of Open Access Journals (Sweden)

    P.I. Lazarenko

    2016-10-01

    Full Text Available Influence of the composition variation along the quasi-binary line GeTe-Sb2Te3 on the thermoelectric and electro-physical properties of thin films was investigated. GST amorphous thin films have high Seebeck coefficients, which drops nearly on the order of magnitude after the crystallization. Temperature dependences of the resistivities were studied, and it was determined that crystallization temperature increases with moving along the quasi-binary line GeTe-Sb2Te3 from GeSb4Te7 to GeSb2Te4, and then to Ge2Sb2Te5, while the phase transition temperature range decreases. Current-voltage characteristics of amorphous thin films have three voltage ranges with different dependencies due to the different mechanisms of charge carrier transport.

  3. Microwave Plasma Chemical Vapor Deposition of Nano-Structured Sn/C Composite Thin-Film Anodes for Li-ion Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, Cynthia; Marcinek, M.; Hardwick, L.J.; Richardson, T.J.; Song, X.; Kostecki, R.

    2008-02-01

    In this paper we report results of a novel synthesis method of thin-film composite Sn/C anodes for lithium batteries. Thin layers of graphitic carbon decorated with uniformly distributed Sn nanoparticles were synthesized from a solid organic precursor Sn(IV) tert-butoxide by a one step microwave plasma chemical vapor deposition (MPCVD). The thin-film Sn/C electrodes were electrochemically tested in lithium half cells and produced a reversible capacity of 440 and 297 mAhg{sup -1} at C/25 and 5C discharge rates, respectively. A long term cycling of the Sn/C nanocomposite anodes showed 40% capacity loss after 500 cycles at 1C rate.

  4. High-Performance Protonic Ceramic Fuel Cells with Thin-Film Yttrium-Doped Barium Cerate-Zirconate Electrolytes on Compositionally Gradient Anodes.

    Science.gov (United States)

    Bae, Kiho; Lee, Sewook; Jang, Dong Young; Kim, Hyun Joong; Lee, Hunhyeong; Shin, Dongwook; Son, Ji-Won; Shim, Joon Hyung

    2016-04-13

    In this study, we used a compositionally gradient anode functional layer (AFL) consisting of Ni-BaCe(0.5)Zr(0.35)Y(0.15)O(3-δ) (BCZY) with increasing BCZY contents toward the electrolyte-anode interface for high-performance protonic ceramic fuel cells. It is identified that conventional homogeneous AFLs fail to stably accommodate a thin film of BCZY electrolyte. In contrast, a dense 2 μm thick BCZY electrolyte was successfully deposited onto the proposed gradient AFL with improved adhesion. A fuel cell containing this thin electrolyte showed a promising maximum peak power density of 635 mW cm(-2) at 600 °C, with an open-circuit voltage of over 1 V. Impedance analysis confirmed that minimizing the electrolyte thickness is essential for achieving a high power output, suggesting that the anode structure is important in stably accommodating thin electrolytes.

  5. Modification of Thin Film Composite (TFC) Membrane by Incorporation with Copper Nanoparticles (Cu-NPs) for Antibacterial Properties

    Science.gov (United States)

    Zhong, Chen

    Membrane biofouling has been a challenging problem restricting the application of reverse osmosis (RO) desalination process. Copper is known for its antimicrobial properties and is easily available with low cost. In this paper, copper nanoparticles (Cu-NPs) with a mean diameter of 15nm were synthesized by the reduction of copper (II) chloride with sodium borohydride (NaBH4), using cetyl trimethylammonium bromide ((C16H33)N(CH3) 3Br, CTAB) as a capping agent. After purification of Cu-NPs by dialysis, the particles were successfully immobilized onto the surface of thin film composite (TFC) membranes via either electrostatic interactions or by covalent bonding with cysteamine as a linker. The electrostatic method was simply to immerse the newly made TFC membranes to the Cu-NPs suspension. Since the CTAB had formed cationic bilayer outside the Cu-NPs, the Cu-NPs was not only adsorbed on the membranes but also attached to the surface because of the electrostatic effect with the negatively charged membrane surface. The covalent bonding method utilized cysteamine (C4H12N2S 2) to activate the thin film layer with thiol functional groups first and then incorporated the metallic copper nanoparticles to form the stable covalent chemical bonding in between. The resulting membranes by these two methods were labeled as TFC-CuNPs and TFC-S-CuNPs, respectively, in this study. Scanning electron microscopy (SEM) imaging and associated energy-dispersive X-ray spectroscopy (EDS) showed that large amounts of Cu-NPs existed on both types of membranes. Surface hydrophilicity of the membranes was enhanced by the presence of Cu-NPs, as indicated by the measured contact angle of 63.25 +/- 0.75 for TFC, 38.63 +/- 2.16 for TFC-CuNPs, and 58.00 +/- 3.39 for TFC-S-CuNPs. Consistently, the water flux obtained from the RO desalination system was increased from 47.07 +/- 0.84 for TFC, 49.10 +/- 0.22 for TFC-CuNPs, and 69.13 +/- 1.43 for TFC-S-CuNPs, with this increase in hydrophilicity. The salt

  6. Implication of conservative and gyroscopic forces on vibration and stability of an elastically tailored rotating shaft modeled as a composite thin-walled beam.

    Science.gov (United States)

    Song, O; Jeong, N H; Librescu, L

    2001-03-01

    Problems related with the implications of conservative and gyroscopic forces on vibration and the stability of a circular cylindrical shaft modeled as a thin-walled composite beam and spinning with constant angular speed about its longitudinal axis are addressed. Taking into account the directionality property of fiber reinforced composite materials, it is shown that for a shaft featuring flapwise-chordwise-bending coupling, a dramatic enhancement of both the vibrational and stability behavior can be reached. In addition, the effects played in the same context by transverse shear, rotatory inertias as well as by the various boundary conditions are discussed and pertinent conclusions are outlined.

  7. Characterization of nanostructured photosensitive (NiS){sub x}(CdS){sub (1-x)} composite thin films grown by successive ionic layer adsorption and reaction (SILAR) route

    Energy Technology Data Exchange (ETDEWEB)

    Ubale, A.U., E-mail: ashokuu@yahoo.com [Nanostructured Thin Film Materials Laboratory, Department of Physics, Govt. Vidarbha Institute of Science and Humanities, Amravati 444604, Maharashtra (India); Bargal, A.N. [Nanostructured Thin Film Materials Laboratory, Department of Physics, Govt. Vidarbha Institute of Science and Humanities, Amravati 444604, Maharashtra (India)

    2011-07-15

    Highlights: {yields} Thin films of (NiS){sub x}(CdS){sub (1-x)} with variable composition (x = 1 to 0) were deposited onto glass substrates by the successive ionic layer adsorption and reaction (SILAR) method. {yields} The structural, surface morphological and electrical characterizations of the as deposited and annealed films were studied. {yields} The bandgap and activation energy of annealed (NiS){sub x}(CdS){sub (1-x)} film decrease with improvement in photosensitive nature. -- Abstract: Recently ternary semiconductor nanostructured composite materials have attracted the interest of researchers because of their photovoltaic applications. Thin films of (NiS){sub x}(CdS){sub (1-x)} with variable composition (x = 1-0) had been deposited onto glass substrates by the successive ionic layer adsorption and reaction (SILAR) method. As grown and annealed films were characterised by X-ray diffraction, scanning electron microscopy and EDAX to investigate structural and morphological properties. The (NiS){sub x}(CdS){sub (1-x)} films were polycrystalline in nature having mixed phase of rhombohedral and hexagonal crystal structure due to NiS and CdS respectively. The optical and electrical properties of (NiS){sub x}(CdS){sub (1-x)} thin films were studied to determine compsition dependent bandgap, activation energy and photconductivity. The bandgap and activation energy of annealed (NiS){sub x}(CdS){sub (1-x)} film decrease with improvement in photosensitive nature.

  8. Surface nanostructuring of thin film composite membranes via grafting polymerization and incorporation of ZnO nanoparticles

    Science.gov (United States)

    Isawi, Heba; El-Sayed, Magdi H.; Feng, Xianshe; Shawky, Hosam; Abdel Mottaleb, Mohamed S.

    2016-11-01

    A new approach for modification of polyamid thin film composite membrane PA(TFC) using synthesized ZnO nanoparticles (ZnO NPs) was shown to enhance the membrane performances for reverse osmosis water desalination. First, active layer of synthesis PA(TFC) membrane was activated with an aqueous solution of free radical graft polymerization of hydrophilic methacrylic acid (MAA) monomer onto the surface of the PA(TFC) membrane resulting PMAA-g-PA(TFC). Second, the PA(TFC) membrane has been developed by incorporation of ZnO NPs into the MAA grafting solution resulting the ZnO NPs modified PMAA-g-PA(TFC) membrane. The surface properties of the synthesized nanoparticles and prepared membranes were investigated using the FTIR, XRD and SEM. Morphology studies demonstrated that ZnO NPs have been successfully incorporated into the active grafting layer over PA(TFC) composite membranes. The zinc leaching from the ZnO NPs modified PMAA-g-PA(TFC) was minimal, as shown by batch tests that indicated stabilization of the ZnO NPs on the membrane surfaces. Compared with the a pure PA(TFC) and PMAA-g-PA(TFC) membranes, the ZnO NPs modified PMAA-g-PA(TFC) was more hydrophilic, with an improved water contact angle (∼50 ± 3°) over the PMAA-g-PA(TFC) (63 ± 2.5°). The ZnO NPs modified PMAA-g-PA(TFC) membrane showed salt rejection of 97% (of the total groundwater salinity), 99% of dissolved bivalent ions (Ca2+, SO42-and Mg2+), and 98% of mono valent ions constituents (Cl- and Na+). In addition, antifouling performance of the membranes was determined using E. coli as a potential foulant. This demonstrates that the ZnO NPs modified PMAA-g-PA(TFC) membrane can significantly improve the membrane performances and was favorable to enhance the selectivity, permeability, water flux, mechanical properties and the bio-antifouling properties of the membranes for water desalination.

  9. Magnetostatic Coupling in CoFe2O4/Pb(Zr0.53Ti0.47)O3 Magnetoelectric Composite Thin Films of 2-2 Type Structure

    Institute of Scientific and Technical Information of China (English)

    Yu-dong Xu; Lei Wang; Min Shi; Hai-lin Su; Guang Wu

    2012-01-01

    CoFe2O4/Pb(Zr0.5aTi0.47)O3 (CFO/PZT) magnetoelectric composite thin films of 2-2 type structure had been prepared onto Pt/Ti/SiO2/Si substrate by a sol-gel process and spin coating technique.The structure of the prepared thin film is substrate/PZT/CFO/PZT/CFO.Two CFO ferromagnetic layers are separated from each other by a thin PZT layer.The upper CFO layer is magnetostatically coupled with the lower CFO layer.Subsequent scanning electron microscopy (SEM) investigations show that the prepared thin films exhibit good morphologies and compact structure,and cross-sectional micrographs clearly display a multilayered nanostructure of multilayered thin films.The composite thin films exhibit both good magnetic and ferroelectric properties.The spacing between ferromagnetic layers can be varied by adjusting the thickness of intermediate PZT layer.It is found that the strength of magnetostatic coupling has a great impact on magnetoelectric properties of composite thin films,i.e.,the magnetoelectric voltage coefficient of composite thin film tends to increase with the decreasing of pacing between two neighboring CFO ferromagnetic layers as a result of magnetostatic coupling effect.

  10. Preparation and characterization of pulsed laser deposited a novel CdS/CdSe composite window layer for CdTe thin film solar cell

    Science.gov (United States)

    Yang, Xiaoyan; Liu, Bo; Li, Bing; Zhang, Jingquan; Li, Wei; Wu, Lili; Feng, Lianghuan

    2016-03-01

    A novel CdS/CdSe composite window structure was designed and then the corresponding films were prepared by pulsed laser deposition as an improved window layer for CdTe-based solar cells. Two types of this composite window structure with 5 cycles and 10 cycles CdS/CdSe respectively both combined with CdS layers were prepared at 200 °C compared with pure CdS window layer and finally were applied into CdTe thin film solar cells. The cross section and surface morphology of the two composite window layers were monitored by using scanning electron microscopy and the result shows that the pulsed laser deposited composite window layers with good crystallinity are stacking together as the design. The devices based on CdS/CdSe composite window layers have demonstrated the enhanced photocurrent collection from both short and long wavelength regions compared to CdS/CdTe solar cell. The efficiency of the best reference CdS/CdTe solar cell was 10.72%. And the device with 5 cycles CdS/CdSe composite window showed efficiency of 12.61% with VOC of 772.92 mV, JSC of 25.11 mA/cm2 and FF of 64.95%. In addition, there are some differences which exist within the optical transmittance spectra and QE curves between the two CdS/CdSe composite window samples, indicating that the volume proportion of CdSe may influence the performance of CdTe thin film solar cell.

  11. Durability Evaluation of a Thin Film Sensor System With Enhanced Lead Wire Attachments on SiC/SiC Ceramic Matrix Composites

    Science.gov (United States)

    Lei, Jih-Fen; Kiser, J. Douglas; Singh, Mrityunjay; Cuy, Mike; Blaha, Charles A.; Androjna, Drago

    2000-01-01

    An advanced thin film sensor system instrumented on silicon carbide (SiC) fiber reinforced SiC matrix ceramic matrix composites (SiC/SiC CMCs), was evaluated in a Mach 0.3 burner rig in order to determine its durability to monitor material/component surface temperature in harsh environments. The sensor system included thermocouples in a thin film form (5 microns thick), fine lead wires (75 microns diameter), and the bonds between these wires and the thin films. Other critical components of the overall system were the heavy, swaged lead wire cable (500 microns diameter) that contained the fine lead wires and was connected to the temperature readout, and ceramic attachments which were bonded onto the CMCs for the purpose of securing the lead wire cables, The newly developed ceramic attachment features a combination of hoops made of monolithic SiC or SiC/SiC CMC (which are joined to the test article) and high temperature ceramic cement. Two instrumented CMC panels were tested in a burner rig for a total of 40 cycles to 1150 C (2100 F). A cycle consisted of rapid heating to 1150 C (2100 F), a 5 minute hold at 1150 C (2100 F), and then cooling down to room temperature in 2 minutes. The thin film sensor systems provided repeatable temperature measurements for a maximum of 25 thermal cycles. Two of the monolithic SiC hoops debonded during the sensor fabrication process and two of the SiC/SiC CMC hoops failed during testing. The hoops filled with ceramic cement, however, showed no sign of detachment after 40 thermal cycle test. The primary failure mechanism of this sensor system was the loss of the fine lead wire-to-thin film connection, which either due to detachment of the fine lead wires from the thin film thermocouples or breakage of the fine wire.

  12. CVD of polymeric thin films: applications in sensors, biotechnology, microelectronics/organic electronics, microfluidics, MEMS, composites and membranes.

    Science.gov (United States)

    Ozaydin-Ince, Gozde; Coclite, Anna Maria; Gleason, Karen K

    2012-01-01

    Polymers with their tunable functionalities offer the ability to rationally design micro- and nano-engineered materials. Their synthesis as thin films have significant advantages due to the reduced amounts of materials used, faster processing times and the ability to modify the surface while preserving the structural properties of the bulk. Furthermore, their low cost, ease of fabrication and the ability to be easily integrated into processing lines, make them attractive alternatives to their inorganic thin film counterparts. Chemical vapor deposition (CVD) as a polymer thin-film deposition technique offers a versatile platform for fabrication of a wide range of polymer thin films preserving all the functionalities. Solventless, vapor-phase deposition enable the integration of polymer thin films or nanostructures into micro- and nanodevices for improved performance. In this review, CVD of functional polymer thin films and the polymerization mechanisms are introduced. The properties of the polymer thin films that determine their behavior are discussed and their technological advances and applications are reviewed.

  13. Dielectric properties of low dielectric constant Ba0.60 Sr0.40Mg0.15Ti0.85O3-Mg2TiO4 composite thin films for tunable applications

    Institute of Scientific and Technical Information of China (English)

    GAO LiNa; ZHAI JiWei; YAO Xi

    2009-01-01

    Ba0.60Sr0.40Mg0.15Ti0.85O3-xmol%Mg2TiO4 (x = 0-40 mol%) (BSTM-MT) composite thin films were fabricated by sol-gel method.The precursor solution of these composite thin films was prepared through mixing the Ba0.60Sr0.40Mg0.15Ti0.85O3 and Mg2Ti04 solution.The microstructures and dielectric tunability of composite thin films were investigated.The dielectric constant of composite thin films can be tailored from 155 to 55 by changing the concentration of Mg2TiO4.The dielectric loss of these composite thin films were still kept below 0.01 and the tunability was above 20% at a dc-applied electric field of 500 kV/cm.Suitable dielectric constant,low dielectric loss,and high tunability of this kind of composite thin films can be useful for potential microwave tunable applications.

  14. Impact of Precursor Compositions on the Structural and Photovoltaic Properties of Spray-Deposited Cu2 ZnSnS4 Thin Films.

    Science.gov (United States)

    Nguyen, Thi Hiep; Fujikawa, Shotaro; Harada, Takashi; Chantana, Jakapan; Minemoto, Takashi; Nakanishi, Shuji; Ikeda, Shigeru

    2016-09-08

    Pure sulfide Cu2 ZnSnS4 thin films were fabricated on Mo-coated glass substrates by facile spray deposition of aqueous precursor solutions containing Cu(NO3 )2 , Zn(NO3 )2 , Sn(CH3 SO3 )2 , and thiourea followed by annealing at 600 °C. When a precursor solution containing a stoichiometric composition of Cu, Zn, and Sn was used, the resulting Cu2 ZnSnS4 thin film contained a Cu2-x S impurity phase owing to the evaporation of Sn components during the annealing process. The Cu2-x S impurity in the Cu2 ZnSnS4 thin film was removed by reducing the concentration of Cu in the precursor solution. This resulted in an improvement of the structural features (i.e., grain sizes and compactness) as well as the electric properties such as acceptor densities, the nature of the acceptor defects, and carrier lifetimes. A solar cell based on the Cu2 ZnSnS4 film with an empirically optimal composition showed conversion efficiency of 8.1 %. The value achieved was one of the best efficiencies of Cu2 ZnSnS4 -based cells derived from a non-vacuum process. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. The synergistic effect of the combined thin multi-walled carbon nanotubes and reduced graphene oxides on photothermally actuated shape memory polyurethane composites.

    Science.gov (United States)

    Yi, Dong Hun; Yoo, Hye Jin; Mahapatra, Sibdas Singha; Kim, Yoong Ahm; Cho, Jae Whan

    2014-10-15

    We evaluated the synergistic effect of the hybrid-type nanocarbon, consisting of 1D thin-walled carbon nanotubes (TWNTs) and 2D reduced graphene oxide (RGO), on the shape memory performance of hyperbranched polyurethane composites. The shape recovery of the resulting composites was activated via a photothermal process using a near-infrared laser. The best laser-induced shape recovery performance was achieved for the composites with a 7/3 of TWNT/RGO ratio and a 1wt.% of nanocarbon content. Such result can be explained by good dispersion of TWNTs and RGO in the hyperbranched polymer as well as three-dimensionally enhanced interconnection between carbon nanotubes and graphenes. The optically active TWNTs with a high optical absorption section exhibited high ability of transferring laser-induced thermal energy to polymer matrix whereas RGO provided a high mechanical property to polymer matrix. The tensile modulus and electrical conductivity of the composites also showed a similar dependence on the TWNT/RGO composition ratio as the photothermal shape recovery. Our study demonstrated an effective conversion from light, thermal to mechanical work by irradiating shape memory polymer composite containing hybrid-type fillers using a near-infrared laser. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. The investigation of ZnO:Al2O3/metal composite back reflectors in amorphous silicon germanium thin film solar cells

    Institute of Scientific and Technical Information of China (English)

    Wang Guang-Hong; Zhao Lei; Yan Bao-Jun; Chen Jing-Wei; Wang Ge; Diao Hong-Wei; Wang Wen-Jing

    2013-01-01

    Different aluminum-doped ZnO (AZO)/metal composite thin films,including AZO/Ag/Al,AZO/Ag/nickelchromium alloy (NiCr),and AZO/Ag/NiCr/Al,are utilized as the back reflectors of p-i-n amorphous silicon germanium thin film solar cells.NiCr is used as diffusion barrier layer between Ag and Al to prevent mutual diffusion,which increases the short circuit current density of solar cell.NiCr and NiCr/Al layers are used as protective layers of Ag layer against oxidation and sulfurization,the higher efficiency of solar cell is achieved.The experimental results show that the performance of a-SiGe solar cell with AZO/Ag/NiCr/Al back reflector is best.The initial conversion efficiency is achieved to be 8.05%.

  17. Selective and Sequential Re-Assembly of Patterned Block Copolymer Thin Film for Fabricating Polymeric, Inorganic, and Their Composite Nanostructured Arrays.

    Science.gov (United States)

    Zu, Xihong; Gong, Jian; Tu, Weiping; Deng, Yulin

    2011-10-04

    We report that the nanostructures of poly(styrene-block-4-vinylpyridine) block copolymer (PS-b-P4VP) thin film on a wafer substrate can be re-assembled by sequential vapor treatment using selected solvents. Metal or other inorganic nanoparticles that were randomly pre-loaded inside or on the surface of PS-b-P4VP thin film could be pulled to the rim of PS and P4VP along with the movements of PS and P4VP blocks during the treatment. As a result, the patterned polymeric or inorganic/polymer composite nanoisland and nanoring arrays were fabricated. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Sol-gel preparation of TiO{sub 2}-ZrO{sub 2} thin films supported on glass rings: Influence of phase composition on photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Alonso, Maria D. [Instituto de Catalisis y Petroleoquimica, CSIC, c/ Marie Curie, 2. Cantoblanco. 28049 Madrid (Spain)]. E-mail: mdhernandez@icp.csic.es; Tejedor-Tejedor, Isabel [Environmental Chemistry and Technology Program, University of Wisconsin, 660 North Park Street, Madison, WI 53706 (United States); Coronado, Juan M. [Instituto de Catalisis y Petroleoquimica, CSIC, c/ Marie Curie, 2. Cantoblanco. 28049 Madrid (Spain)]. E-mail: juanmanuel.coronado@ciemat.es; Soria, Javier [Instituto de Catalisis y Petroleoquimica, CSIC, c/ Marie Curie, 2. Cantoblanco. 28049 Madrid (Spain); Anderson, Marc A. [Environmental Chemistry and Technology Program, University of Wisconsin, 660 North Park Street, Madison, WI 53706 (United States)

    2006-04-28

    In order to optimize the characteristics of TiO{sub 2}-ZrO{sub 2} thin films supported on glass for the photocatalytic removal of VOCs, acidic sols of different composition (ZrO{sub 2}, TiO{sub 2} and Ti-Zr mixed oxides) have been prepared using metal alkoxides as starting materials. The photoactive oxides were deposited on 'Raschig rings' of borosilicate glass using a dip-coating technique. The phase composition of the thin films was controlled during the sol preparation stage to produce either (1) Ti{sub 0.9}Zr{sub 0.1}O{sub 2} solid solutions, or (2) ZrO{sub 2}/TiO{sub 2} binary metal oxides (10% and 20% molar content of Zr). The particle size of the different sols was measured by photon correlation spectroscopy, and the xerogels were characterized by XRD, N{sub 2} adsorption isotherms, and TG-DTA, so as to monitor the modifications induced by the thermal treatments. Raman spectroscopy was used to determine the crystalline structure of the supported TiO{sub 2}-ZrO{sub 2} oxides, which in all cases corresponded to the anatase phase. The band gap of the thin films was estimated from the UV-vis spectra, and none of them differed significantly from that of unmodified TiO{sub 2}. The photoactivity of the coated glass 'Raschig rings' was measured for the oxidation of acetone and methylcyclohexane vapors using, respectively, total recycle and single pass plug flow photoreactors. The results obtained indicate that, for the same Zr content, the photoactivity of the films containing binary metal oxides is slightly higher than that of the solid solution. In contrast, specific surface area seems to have little influence on the performance of the thin films.

  19. Composition variations in Cu{sub 2}ZnSnSe{sub 4} thin films analyzed by X-ray diffraction, energy dispersive X-ray spectroscopy, particle induced X-ray emission, photoluminescence, and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Dahyun [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of); Opanasyuk, A.S.; Koval, P.V.; Ponomarev, A.G. [Department of Electronics and Computer Technology, Sumy State University, Sumy UA-40007 (Ukraine); Jeong, Ah Reum; Kim, Gee Yeong; Jo, William [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Cheong, Hyeonsik, E-mail: hcheong@sogang.ac.kr [Department of Physics, Sogang University, Seoul 121-742 (Korea, Republic of)

    2014-07-01

    Compositional and structural studies of Cu{sub 2}ZnSnSe{sub 4} (CZTSe) thin films were carried out by X-ray diffraction, energy dispersive X-ray spectroscopy (EDS), particle induced X-ray emission (PIXE), photoluminescence, and Raman spectroscopy. CZTSe thin films with different compositions were deposited on sodalime glass by co-evaporation. The composition of the films measured by two different methods, EDS and PIXE, showed significant differences. Generally, the Zn/Sn ratio measured by EDS is larger than that measured by PIXE. Both the micro-PIXE and the micro-Raman imaging results indicated the compositional and structural inhomogeneity of the sample. - Highlights: • Particle induced X-ray emission was used to analyze the composition of CZTSe films. • Energy dispersive X-ray spectroscopy tends to underestimate the Sn composition. • Local Raman intensity is related with the composition rather than the crystallinity.

  20. IER 203 CED-2 Report: LLNL Final Design for BERP Ball With a Composite Reflector of Thin Polyethylene Backed by Nickel

    Energy Technology Data Exchange (ETDEWEB)

    Percher, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinrichs, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kim, S. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-07-18

    This report documents the results of final design (CED-2) for IER 203, BERP Ball Composite Reflection, and focuses on critical configurations with a 4.5 kg α-phase plutonium sphere reflected by a combination of thin high-density polyethylene (HDPE) backed by a thick nickel reflector. The Lawrence Livermore National Laboratory’s (LLNL’s) Nuclear Criticality Safety Division, in support of fissile material operations, calculated surprisingly reactive configurations when a fissile core was surrounded by a thin, moderating reflector backed by a thick metal reflector. These composite reflector configurations were much more reactive than either of the single reflector materials separately. The calculated findings have resulted in a stricter-than-anticipated criticality control set, impacting programmatic work. IER 203 was requested in response to these seemingly anomalous calculations to see if the composite reflection effect could be shown experimentally. This report focuses on the Beryllium Reflected Plutonium (BERP) ball as a fissile material core reflected by polyethylene and nickel. A total of four critical configurations were designed as part of CED-2. Fabrication costs are estimated to be $98,500, largely due to the cost of the large nickel reflectors. The IER 203 experiments could reasonably be expected to begin in early FY2017.

  1. IER 203 CED-2 Report: LLNL Final Design for BERP Ball With a Composite Reflector of Thin Polyethylene Backed by Nickel

    Energy Technology Data Exchange (ETDEWEB)

    Percher, C. M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Heinrichs, D. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kim, S. K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-07-18

    This report documents the results of final design (CED-2) for IER 203, BERP Ball Composite Reflection, and focuses on critical configurations with a 4.5 kg α-phase plutonium sphere reflected by a combination of thin high-density polyethylene (HDPE) backed by a thick nickel reflector. The Lawrence Livermore National Laboratory’s (LLNL’s) Nuclear Criticality Safety Division, in support of fissile material operations, calculated surprisingly reactive configurations when a fissile core was surrounded by a thin, moderating reflector backed by a thick metal reflector. These composite reflector configurations were much more reactive than either of the single reflector materials separately. The calculated findings have resulted in a stricter-than-anticipated criticality control set, impacting programmatic work. IER 203 was requested in response to these seemingly anomalous calculations to see if the composite reflection effect could be shown experimentally. This report focuses on the Beryllium Reflected Plutonium (BERP) ball as a fissile material core reflected by polyethylene and nickel. A total of four critical configurations were designed as part of CED-2. Fabrication costs are estimated to be $98,500, largely due to the cost of the large nickel reflectors. The IER 203 experiments could reasonably be expected to begin in early FY2017,

  2. Effects of cation compositions on the electronic properties and optical dispersion of indium zinc tin oxide thin films by electron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Denny, Yus Rama [Department of Electrical Engineering, University of Sultan Ageng Tirtayasa, Banten 42435 (Indonesia); Seo, Soonjoo [Division of Materials Science, Korea Basic Science Institute, Daejeon 305-806 (Korea, Republic of); Lee, Kangil; Oh, Suhk Kun [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kang, Hee Jae, E-mail: hjkang@cbu.ac.kr [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Heo, Sung; Chung, Jae Gwan; Lee, Jae Cheol [Analytical Engineering Center, Samsung Advanced Institute of Technology, Suwon 440-600 (Korea, Republic of); Tougaard, Sven [Department of Physics, Chemistry, and Pharmacy, University of Southern Denmark, DK-5230 Odense M. (Denmark)

    2015-02-15

    Highlights: • REELS analysis can provide optical dispersion and electronic properties of oxide materials. • The band gap varied with In/Zn/Sn compositions and increased after annealing. • The optical properties were examined using REELS in conjunction with the Tougaard–Yubero model. • The dispersion parameters were determined by a single-oscillator Wemple–DiDomenico model. • The Zn and Sn contents play a crucial role in determining the single-oscillator constant and dispersion energy of IZTO thin films. - Abstract: The electronic properties and optical dispersion of indium zinc tin oxide (IZTO) films with different cation compositions were investigated by reflection electron energy loss spectroscopy (REELS). The REELS spectra of IZTO films revealed that the band gap varied with different Sn/Zn ratios and In content. The optical properties were examined with REELS data using Tougaard–Yubero model and the results were compared with the envelope of the transmission spectra obtained using a UV-spectrometer. The dispersion behavior of the refractive index from REELS results was studied in terms of the single-oscillator Wemple–DiDomenico model. The results showed that the different compositions of In/Zn/Sn caused a change in the dispersion parameters of IZTO thin films in contrast to the static values of refractive indices and dielectric constant which remained the same. Our work demonstrated that REELS is an efficient tool to study the optical properties of a material by obtaining the optical parameters.

  3. Supplementary Material for: Lignocellulose-derived thin stillage composition and efficient biological treatment with a high-rate hybrid anaerobic bioreactor system

    KAUST Repository

    Oosterkamp, Margreet

    2016-01-01

    Abstract Background This study aims to chemically characterize thin stillage derived from lignocellulosic biomass distillation residues in terms of organic strength, nutrient, and mineral content. The feasibility of performing anaerobic digestion on these stillages at mesophilic (40 °C) and thermophilic (55 °C) temperatures to produce methane was demonstrated. The microbial communities involved were further characterized. Results Energy and sugar cane stillage have a high chemical oxygen demand (COD of 43 and 30 g/L, respectively) and low pH (pH 4.3). Furthermore, the acetate concentration in sugar cane stillage was high (45 mM) but was not detected in energy cane stillage. There was also a high amount of lactate in both types of stillage (35–37 mM). The amount of sugars was 200 times higher in energy cane stillage compared to sugar cane stillage. Although there was a high concentration of sulfate (18 and 23 mM in sugar and energy cane stillage, respectively), both thin stillages were efficiently digested anaerobically with high COD removal under mesophilic and thermophilic temperature conditions and with an organic loading rate of 15–21 g COD/L/d. The methane production rate was 0.2 L/g COD, with a methane percentage of 60 and 64, and 92 and 94 % soluble COD removed, respectively, by the mesophilic and thermophilic reactors. Although both treatment processes were equally efficient, there were different microbial communities involved possibly arising from the differences in the composition of energy cane and sugar cane stillage. There was more acetic acid in sugar cane stillage which may have promoted the occurrence of aceticlastic methanogens to perform a direct conversion of acetate to methane in reactors treating sugar cane stillage. Conclusions Results showed that thin stillage contains easily degradable compounds suitable for anaerobic digestion and that hybrid reactors can efficiently convert thin stillage to methane under mesophilic and

  4. Full-mouth composite rehabilitation of a mixed erosion and attrition patient: a case report with v-shaped veneers and ultra-thin CAD/CAM composite overlays.

    Science.gov (United States)

    Bahillo, Jose; Jané, Luis; Bortolotto, Tissiana; Krejci, Ivo; Roig, Miguel

    2014-10-01

    Loss of tooth substance has become a common pathology in modern society. It is of multifactorial origin, may be induced by a chemical process or by excessive attrition, and frequently has a combined etiology. Particular care should be taken when diagnosing the cause of dental tissue loss, in order to minimize its impact. Several publications have proposed the use of minimally invasive procedures to treat such patients in preference to traditional full-crown rehabilitation. The use of composite resins, in combination with improvements in dental adhesion, allows a more conservative approach. In this paper, we describe the step-by-step procedure of full-mouth composite rehabilitation with v-shaped veneers and ultra-thin computer-aided design/computer-assisted manufacture (CAD/CAM)- generated composite overlays in a young patient with a combination of erosion and attrition disorder.

  5. 1-J operation of monolithic composite ceramics with Yb:YAG thin layers: multi-TRAM at 10-Hz repetition rate and prospects for 100-Hz operation.

    Science.gov (United States)

    Divoky, Martin; Tokita, Shigeki; Hwang, Sungin; Kawashima, Toshiyuki; Kan, Hirofumi; Lucianetti, Antonio; Mocek, Tomas; Kawanaka, Junji

    2015-03-15

    Experimental amplification of 10-ns pulses to energy of 1 J at repetition rate of 10-100 Hz in cryogenic multipass total-reflection active-mirror (TRAM) amplifier is reported for the first time. By using a monolithic multi-TRAM, which is a YAG ceramic composite with three thin Yb:YAG active layers, efficient energy extraction was achieved without parasitic lasing. A detailed measurement of output characteristics of the laser amplifier is presented; results are discussed and compared with numerical calculations.

  6. Compositional Dependence of the Optical Properties of Amorphous Semiconducting Glass Se80Ge20- x Cd x (0 ≤ x ≤ 12 at.%) Thin Films

    Science.gov (United States)

    Hegab, N. A.; Farid, A. S.; Shakra, A. M.; Afifi, M. A.; Alrebati, A. M.

    2016-07-01

    Se80Ge20- x Cd x (0 ≤ x ≤ 12 at.%) compositions were prepared by a quenching technique. Thin films of the obtained compositions were deposited on dry clean glass substrates by a thermal evaporation technique. The chemical composition of the film samples have been determined by energy dispersive x-ray spectroscopy (EDX). X-ray diffraction measurements showed the amorphous nature of the studied films. The optical constants ( n, k) were determined for the studied films using spectrophotometric measurements of transmittance T( λ) in the wavelength range (350 nm to 2500 nm), and using Swanepoel's method. The values of the dispersion energy E d, oscillator energy E o, the lattice dielectric constant ɛ ∞L and the high-frequency dielectric constant ɛ s were determined. The optical band gap Eg^{{opt}} is estimated for all compositions from the absorption coefficient α. The analysis of the optical absorption data revealed the existence of allowed indirect transitions for all compositions. The effect of adding Cd content on the obtained optical parameters was also discussed.

  7. Development of an embedded thin-film strain-gauge-based SHM network into 3D-woven composite structure for wind turbine blades

    Science.gov (United States)

    Zhao, Dongning; Rasool, Shafqat; Forde, Micheal; Weafer, Bryan; Archer, Edward; McIlhagger, Alistair; McLaughlin, James

    2017-04-01

    Recently, there has been increasing demand in developing low-cost, effective structure health monitoring system to be embedded into 3D-woven composite wind turbine blades to determine structural integrity and presence of defects. With measuring the strain and temperature inside composites at both in-situ blade resin curing and in-service stages, we are developing a novel scheme to embed a resistive-strain-based thin-metal-film sensory into the blade spar-cap that is made of composite laminates to determine structural integrity and presence of defects. Thus, with fiberglass, epoxy, and a thinmetal- film sensing element, a three-part, low-cost, smart composite laminate is developed. Embedded strain sensory inside composite laminate prototype survived after laminate curing process. The internal strain reading from embedded strain sensor under three-point-bending test standard is comparable. It proves that our proposed method will provide another SHM alternative to reduce sensing costs during the renewable green energy generation.

  8. Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors.

    Science.gov (United States)

    Wang, Xinhua; Zhao, Yanxiao; Yuan, Bo; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

    2016-02-01

    There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-D-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-D-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties.

  9. Effect of small changes in composition on the electrical and structural properties of YBa sub 2 Cu sub 3 O sub 7 thin films

    Energy Technology Data Exchange (ETDEWEB)

    Chew, N.G.; Goodyear, S.W.; Edwards, J.A.; Satchell, J.S.; Blenkinsop, S.E.; Humphreys, R.G. (Royal Signals and Radar Establishment, Malvern, Worcestershire (United Kingdom))

    1990-11-05

    Epitaxial thin films of YBa{sub 2}Cu{sub 3}O{sub 7} have been grown {ital in} {ital situ} by evaporation onto (001) MgO substrates. The composition was varied systematically to investigate the effects of changes in Cu content and Ba/Y ratio on the film properties. The results demonstrate that deviations from stoichiometry at the limit of resolution of most analytic techniques can have a large effect on structural and transport properties, as well as causing marked changes in surface morphology. The best properties ({ital J}{sub {ital c}}{gt}3{times}10{sup 6} A/cm{sup 2} at 77 K) are only found for a narrow range of compositions, which can be readily identified from the surface morphology.

  10. Liquid and Gas Permeation Studies on the Structure and Properties of Polyamide Thin-Film Composite Membranes

    KAUST Repository

    Duan, Jintang

    2014-11-01

    This research was undertaken to improve the understanding of structure-property-performance relationships in crosslinked polyamide (PA) thin-film composite (TFC) membranes as characterized by liquid and gas permeation studies. The ultrathin PA selective layer formed by interfacial polymerization between meta-phenylene diamine and trimesoyl chloride was confirmed to contain dense polymer matrix regions and defective regions in both dry and hydrated states. The first part of this research studied the effect of non-selective convection through defective regions on water flux and solute flux in pressure-assisted forward osmosis (PAFO). Through systematic comparison with cellulose triacetate (CTA) and PEBAX-coated PA-TFC membranes, the existence of defects in pristine, hydrated PA-TFC membranes was verified, and their effects were quantified by experimental and modeling methods. In the membrane orientation of selective layer facing the draw solution, water flux increases of up to 10-fold were observed to result from application of low hydraulic pressure (1.25 bar). Convective water flux through the defects was low (< 1% of total water flux for PA-TFC membranes) and of little consequence in practical FO or reverse osmosis (RO) applications. However, it effectively mitigated the concentration polarization in PAFO and therefore greatly increased the diffusive flux through the dense regions. The second part of this research characterized the structures of the PA material and the PA selective layer by gas adsorption and gas permeation measurements. Gas adsorption isotherms (N2 at 77K, CO2 at 273K) confirmed the microporous nature of PA in comparison with dense CTA and polysulfone materials. Gas permeation through the commercial PA-TFC membranes tested occurred primarily in the defective regions, resulting in Knudsen gas selectivity for various gas pairs. Applying a Nafion coating layer effectively plugged the defects and allowed gas permeation through the dense PA regions

  11. The propagation characteristics of the plate modes of acoustic emission waves in thin aluminum plates and thin graphite/epoxy composite plates and tubes. Ph.D. Thesis - Johns Hopkins Univ., 1991

    Science.gov (United States)

    Prosser, William H.

    1991-01-01

    Acoustic emission was interpreted as modes of vibration in plates. Classical plate theory was used to predict dispersion curves for the two fundamental modes and to calculate the shapes of flexural waveforms produced by vertical step function loading. There was good agreement between theoretical and experimental results for aluminum. Composite materials required the use of a higher order plate theory (Reissner-Mindlin) to get good agreement with the measured velocities. Four composite plates with different laminate stacking sequences were studied. The dispersion curves were determined from phase spectra of the time dependent waveforms. Plate modes were shown to be useful for determining the direction of source motion. Aluminum plates were loaded by breaking a pencil lead against their surface. By machining slots at angles to the plane of a plate, the direction in which the force acted was varied. Changing the source motion direction produced regular variations in the waveforms. To demonstrate applicability beyond simple plates, waveforms produced by lead breaks on a thin walled composite tube were also shown to be interpretable as plate modes. The tube design was based on the type of struts proposed for Space Station Freedom's trussed structures.

  12. Investigation on multiferroic, optical and photoluminescence properties of CoFe2O4/(Pb1-xSrx)TiO3 nanostructured composite thin films

    Science.gov (United States)

    Bala, Kanchan; Sharma, Pankaj; Negi, N. S.

    2016-11-01

    Multiferroic nanostructured composite thin films consisting of CoFe2O4 (CFO) and Pb1-xSrxTiO3 (PST; x = 0.1, 0.2, 0.3, 0.4 and 0.5) layers have been deposited on Pt/TiO2/SiO2/Si and quartz substrates by using metallo-organic decomposition process and spin coating. The effect of Sr content on the multiferroic and optical properties have been investigated. The phase purity such as spinel structure of CFO and perovskite structure of PST has been verified by X-ray diffraction. Cross-sectional scanning electron microscopy images revealed clear interface between CFO and PST layers without any noticeable diffusion. The multiferroic properties of CFO/PST composite films have been confirmed by magnetic and ferroelectric hysteresis loops with low leakage current density. The residual strain sensitivity of multiferroic and optical properties has been observed in the composite films. The decrease in saturation magnetization and saturation polarization with increase in Sr content has been observed which could be attributed to the decrease in residual strain of CFO/PST composite films. The magnetic phase transition temperature of the CFO/PST composite films is also reduced. The optical refractive index decreases with increase of amount of Sr content. The photoluminescence spectra of the CFO/PST composite films possess a blue shift which can be attributed to the Pb and oxygen vacancies as localized sensitizing centers. We show that the multiferroic and optical properties of the CFO/PST composite films are highly sensitive to the heterostructure strains which can be controlled by Sr content.

  13. Analysis of thin-walled cylindrical composite shell structures subject to axial and bending loads: Concept development, analytical modeling and experimental verification

    Science.gov (United States)

    Mahadev, Sthanu

    Continued research and development efforts devoted in recent years have generated novel avenues towards the advancement of efficient and effective, slender laminated fiber-reinforced composite members. Numerous studies have focused on the modeling and response characterization of composite structures with particular relevance to thin-walled cylindrical composite shells. This class of shell configurations is being actively explored to fully determine their mechanical efficacy as primary aerospace structural members. The proposed research is targeted towards formulating a composite shell theory based prognosis methodology that entails an elaborate analysis and investigation of thin-walled cylindrical shell type laminated composite configurations that are highly desirable in increasing number of mechanical and aerospace applications. The prime motivation to adopt this theory arises from its superior ability to generate simple yet viable closed-form analytical solution procedure to numerous geometrically intense, inherent curvature possessing composite structures. This analytical evaluative routine offers to acquire a first-hand insight on the primary mechanical characteristics that essentially govern the behavior of slender composite shells under typical static loading conditions. Current work exposes the robustness of this mathematical framework via demonstrating its potential towards the prediction of structural properties such as axial stiffness and bending stiffness respectively. Longitudinal ply-stress computations are investigated upon deriving the global stiffness matrix model for composite cylindrical tubes with circular cross-sections. Additionally, this work employs a finite element based numerical technique to substantiate the analytical results reported for cylindrically shaped circular composite tubes. Furthermore, this concept development is extended to the study of thin-walled, open cross-sectioned, curved laminated shells that are geometrically

  14. Highly-flexible, ultra-thin, and transparent single-layer graphene/silver composite electrodes for organic light emitting diodes

    Science.gov (United States)

    Li, Kun; Wang, Hu; Li, Huiying; Li, Ye; Jin, Guangyong; Gao, Lanlan; Marco, Mazzeo; Duan, Yu

    2017-08-01

    Transparent conductive electrode (TCE) platforms are required in many optoelectronic devices, including organic light emitting diodes (OLEDs). To date, indium tin oxide based electrodes are widely used in TCEs but they still have few limitations in term of achieving flexible OLEDs and display techniques. In this paper, highly-flexible and ultra-thin TCEs were fabricated for use in OLEDs by combining single-layer graphene (SLG) with thin silver layers of only several nanometers in thickness. The as-prepared SLG + Ag (8 nm) composite electrodes showed low sheet resistances of 8.5 Ω/□, high stability over 500 bending cycles, and 74% transmittance at 550 nm wavelength. Furthermore, SLG + Ag composite electrodes employed as anodes in OLEDs delivered turn-on voltages of 2.4 V, with luminance exceeding 1300 cd m-2 at only 5 V, and maximum luminance reaching up 40 000 cd m-2 at 9 V. Also, the devices could work normally under less than the 1 cm bending radius.

  15. Compositional analysis and depth profiling of thin film CrO{sub 2} by heavy ion ERDA and standard RBS: a comparison

    Energy Technology Data Exchange (ETDEWEB)

    Khamlich, S., E-mail: skhamlich@gmail.com [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); Department of Chemistry, Tshwane University of Technology, Private Bag X 680, Pretoria, 0001 (South Africa); The African Laser Centre, CSIR campus, P.O. Box 395, Pretoria (South Africa); Msimanga, M., E-mail: mandla@tlabs.ac.za [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); iThemba LABS Gauteng, Private Bag 11, WITS 2050, Johannesburg (South Africa); Pineda-Vargas, C.A. [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); Faculty of Health and Wellness Sciences, C.P.U.T., P.O. Box 1906, Bellville 7535 (South Africa); Nuru, Z.Y. [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); McCrindle, R. [Department of Chemistry, Tshwane University of Technology, Private Bag X 680, Pretoria, 0001 (South Africa); Maaza, M. [Nano-Sciences Laboratories, Materials Research Department, iThemba LABS, P.O. Box 722, Somerset West 7129 (South Africa); Department of Chemistry, Tshwane University of Technology, Private Bag X 680, Pretoria, 0001 (South Africa); The African Laser Centre, CSIR campus, P.O. Box 395, Pretoria (South Africa)

    2012-08-15

    Chromium dioxide (CrO{sub 2}) thin film has generated considerable interest in applied research due to the wide variety of its technological applications. It has been extensively investigated in recent years, attracting the attention of researchers working on spintronic heterostructures and in the magnetic recording industry. However, its synthesis is usually a difficult task due to its metastable nature and various synthesis techniques are being investigated. In this work a polycrystalline thin film of CrO{sub 2} was prepared by electron beam vaporization of Cr{sub 2}O{sub 3} onto a Si substrate. The polycrystalline structure was confirmed through XRD analysis. The stoichiometry and elemental depth distribution of the deposited film were measured by ion beam nuclear analytical techniques heavy ion elastic recoil detection analysis (ERDA) and Rutherford backscattering spectrometry (RBS), which both have relative advantage over non-nuclear spectrometries in that they can readily provide quantitative information about the concentration and distribution of different atomic species in a layer. Moreover, the analysis carried out highlights the importance of complementary usage of the two techniques to obtain a more complete description of elemental content and depth distribution in thin films. - Graphical abstract: Heavy ion elastic recoil detection analysis (ERDA) and Rutherford backscattering spectrometry (RBS) both have relative advantage over non-nuclear spectrometries in that they can readily provide quantitative information about the concentration and distribution of different atomic species in a layer. Highlights: Black-Right-Pointing-Pointer Thin films of CrO{sub 2} have been grown by e-beam evaporation of Cr{sub 2}O{sub 3} target in vacuum. Black-Right-Pointing-Pointer The composition was determined by heavy ion-ERDA and RBS. Black-Right-Pointing-Pointer HI-ERDA and RBS provided information on the light and heavy elements, respectively.

  16. Determination of the compositions of the DIGM zone in nanocrystalline Ag/Au and Ag/Pd thin films by secondary neutral mass spectrometry

    Directory of Open Access Journals (Sweden)

    Gábor Y. Molnár

    2016-03-01

    Full Text Available Alloying by grain boundary diffusion-induced grain boundary migration is investigated by secondary neutral mass spectrometry depth profiling in Ag/Au and Ag/Pd nanocrystalline thin film systems. It is shown that the compositions in zones left behind the moving boundaries can be determined by this technique if the process takes place at low temperatures where solely the grain boundary transport is the contributing mechanism and the gain size is less than the half of the grain boundary migration distance. The results in Ag/Au system are in good accordance with the predictions given by the step mechanism of grain boundary migration, i.e., the saturation compositions are higher in the slower component (i.e., in Au or Pd. It is shown that the homogenization process stops after reaching the saturation values and further intermixing can take place only if fresh samples with initial compositions, according to the saturation values, are produced and heat treated at the same temperature. The reversal of the film sequence resulted in the reversal of the inequality of the compositions in the alloyed zones, which is in contrast to the above theoretical model, and explained by possible effects of the stress gradients developed by the diffusion processes itself.

  17. Photoactivity and hydrophilic property of SiO2 and SnO2 co-doped TiO2 nano-composite thin films

    Directory of Open Access Journals (Sweden)

    Lek Sikong

    2010-08-01

    Full Text Available SiO2 and SnO2 co-doped TiO2 nano-composite thin films were prepared by sol-gel method. The effects of film thicknessand amount of SiO2 and SnO2 co-doping into TiO2 nano-composite films on phase presence, crystallite size, photocatalyticreaction and hydrophilicity were investigated. Thickness of 3-coating layers (238 nm seems to provide the highest photocatalyticactivity. The crystallinity of anatase phases, crystallite sizes and photocatalytic reactions of SiO2 and SnO2 co-dopedTiO2 films decrease with an increase in SiO2 content. It was found that more amount of SiO2 addition seems to inhibit graingrowth and the formation of anatase phase; especially when it was synthesized at temperature less than 600°C. The photocatalyticreaction seems to decrease with an increase in SiO2 doping when the concentrations of SnO2 in the composite films are fixed. It was apparent that 1SiO2/1SnO2/TiO2 composite film exhibits the highest photoactivity. Suitable amounts of SiO2and SnO2 doping into the TiO2 composite films tend to enhance the hydrophilic property of the films. It was also apparentthat the 3SiO2/3SnO2/TiO2, 5SiO2/5SnO2/TiO2 and 10SiO2/3SnO2/TiO2 composite films exhibit super hydrophilic characteristicsunder UV irradiation for 30 min.

  18. Microstructure and optical dispersion characterization of nanocomposite sol-gel TiO2-SiO2 thin films with different compositions

    Science.gov (United States)

    Kermadi, S.; Agoudjil, N.; Sali, S.; Zougar, L.; Boumaour, M.; Broch, L.; En Naciri, A.; Placido, F.

    2015-06-01

    Nanocomposite TiO2-SiO2 thin films with different compositions (from 0 to 100 mol% TiO2) were deposited by sol-gel dip-coating method on silicon substrate. Crystal structure, chemical bonding configuration, composition and morphology evolutions with composition were followed by Raman scattering, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy and scanning electron microscopy respectively. The refractive index and the extinction coefficient were derived in a broad band wavelength (250-900 nm) from spectroscopic ellipsometry data with high accuracy and correlated with composition and microstructure. Results showed an anatase structure for 100% TiO2 with a grain size in 6-10 nm range. Whereas, the inclusion of SiO2 enlarges the optical band gap and suppresses the grain growth up to 4 nm in size. High TiO2 dispersion in SiO2 matrix was observed for all mixed materials. The refractive index (at λ = 600 nm) increases linearly with composition from 1.48 (in 100% SiO2) to 2.22 (in 100% TiO2) leading to lower dense material, its dispersion being discussed in terms of the Wemple-DiDomenico single oscillator model. Hence, the optical parameters, such optical dispersion energies E0 and Ed, the average oscillators, strength S0 and wavelength λ0 and the ratio of the carrier concentration to the effective mass N/m∗ have been derived. The analysis revealed a strong dependence on composition and structure. The optical response was also investigated in term of complex optical conductivity (σ) and both volume and surface energy loss functions (VELF and SELF).

  19. Lignocellulose-derived thin stillage composition and efficient biological treatment with a high-rate hybrid anaerobic bioreactor system

    OpenAIRE

    Oosterkamp, Margreet J.; Méndez-García, Celia; Kim, Chang-H.; Bauer, Stefan; Ibáñez, Ana B.; Zimmerman, Sabrina; Hong, Pei-Ying; Cann, Isaac K.; Mackie, Roderick I.

    2016-01-01

    Background This study aims to chemically characterize thin stillage derived from lignocellulosic biomass distillation residues in terms of organic strength, nutrient, and mineral content. The feasibility of performing anaerobic digestion on these stillages at mesophilic (40 °C) and thermophilic (55 °C) temperatures to produce methane was demonstrated. The microbial communities involved were further characterized. Results Energy and sugar cane stillage have a high chemical oxygen demand (COD o...

  20. Experimental and Theoretical Research on the Vibrational Gaps in Two-Dimensional Three-Component Composite Thin Plates

    Institute of Scientific and Technical Information of China (English)

    YU Dian-Long; LIU Yao-Zong; QIU Jing; ZHAO Hong-Gang; LIU Zhi-Ming

    2005-01-01

    @@ We investigate the vibrational band gaps in a thin plate of two-dimensional phononic crystals with the locally resonant structure in theory and experiment. The experimental sample is optimized based on the simple analytical model. The experimental results are in good agreement with the theoretical calculation by the finite element method. The findings will be significant for applications of phononic crystals in the field of vibration isolation.

  1. Binary metal oxide nanoparticle incorporated composite multilayer thin films for sono-photocatalytic degradation of organic pollutants

    Science.gov (United States)

    Gokul, Paramasivam; Vinoth, Ramalingam; Neppolian, Bernaurdshaw; Anandhakumar, Sundaramurthy

    2017-10-01

    We report reduced graphene oxide (rGO) supported binary metal oxide (CuO-TiO2/rGO) nanoparticle (NP) incorporated multilayer thin films based on Layer-by-Layer (LbL) assembly for enhanced sono-photocatalytic degradation of methyl orange under exposure to UV radiation. Multilayer thin films were fabricated on glass and quartz slides, and investigated using scanning electron microscopy and UV-vis spectroscopy. The loading of catalyst NPs on the film resulted in the change of morphology of the film from smooth to rough with uniformly distributed NPs on the surface. The growth of the control and NP incorporated films followed a linear regime as a function of number of layers. The%degradation of methyl orange as a function of time was investigated by UV-vis spectroscopy and total organic carbon (TOC) measurements. Complete degradation of methyl orange was achieved within 13 h. The amount of NP loading in the film significantly influenced the%degradation of methyl orange. Catalyst reusability studies revealed that the catalyst thin films could be repeatedly used for up to five times without any change in photocatalytic activity of the films. The findings of the present study support that the binary metal oxide catalyst films reported here are very useful for continuous systems, and thus, making it an option for scale up.

  2. 反渗透复合膜最新研究进展%Progress on thin-film composite(TFC)reverse osmosis membrane

    Institute of Scientific and Technical Information of China (English)

    张所波; 张奇峰; 李胜海

    2013-01-01

    Reverse osmosis (RO) membranes have been widely used in seawater desalination,ultrapure water production,wastewater treatment,pharmaceutical and biological industries.The whole aromatic polyamide thin-film composite membrane (TFC) is the most successful reverse osmosis membrane nowadays.The performance of reverse osmosis membrane is decided by the physical structures and chemical properties of the ultra-thin polyamide layer.Progress on reverse osmosis composite membrane,including the formation process of interfacially polymerized composite membrane,novel monomers used for interfacial polymerization,the additives,nano hybrid reverse osmosis membrane,highly chlorine-tolerant reverse osmosis membrane and new characterization methods for reverse osmosis membranes are introduced briefly in this review.%反渗透膜在海水淡化、超纯水制备、污水处理、制药及生物技术等领域得到了广泛应用.目前,最成功的反渗透膜是通过界面聚合方法制备的以交联聚酰胺为分离皮层的复合膜.交联聚酰胺皮层的结构和性质对最终反渗透膜的分离性能起关键作用.本文简要介绍了界面聚合复合膜的形成过程和结构、新型界面聚合功能单体、界面聚合反应添加剂、纳米杂化反渗透复合膜、高耐氯氧化性反渗透膜,以及反渗透复合膜表征方法创新等方面的研究进展和发展趋势.

  3. One-step electrochemical preparation of the ternary (Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} thin films on Au(1 1 1): Composition-dependent growth and characterization studies

    Energy Technology Data Exchange (ETDEWEB)

    Erdogan, Ibrahim Y. [Bingoel University, Sciences and Arts Faculty, Department of Chemistry, 12000, Bingoel (Turkey); Demir, Umit, E-mail: udemir@atauni.edu.t [Atatuerk University, Sciences Faculty, Department of Chemistry, 25240, Erzurum (Turkey)

    2010-09-01

    This study reports on the synthesis of ternary semiconductor (Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} thin films on Au(1 1 1) using a practical electrochemical method, based on the simultaneous underpotential deposition (UPD) of Bi, Sb and Te from the same solution containing Bi{sup 3+}, SbO{sup +}, and HTeO{sub 2}{sup +} at a constant potential. The thin films are characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive spectroscopy (EDS) and reflection absorption-FTIR (RA-FTIR) to determine structural, morphological, compositional and optic properties. The ternary thin films of (Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} with various compositions (0.0 {<=} x {<=} 1.0) are highly crystalline and have a kinetically preferred orientation at (0 1 5) for hexagonal crystal structure. AFM images show uniform morphology with hexagonal-shaped crystals deposited over the entire gold substrate. The structure and composition analyses reveal that the thin films are pure phase with corresponding atomic ratios. The optical studies show that the band gap of (Bi{sub x}Sb{sub 1-x}){sub 2}Te{sub 3} thin films could be tuned from 0.17 eV to 0.29 eV as a function of composition.

  4. Growth of Ni and Ni-Cr alloy thin films on MgO(001): Effect of alloy composition on surface morphology

    Science.gov (United States)

    Ramalingam, Gopalakrishnan; Reinke, Petra

    2016-12-01

    The effects of substrate treatment, growth temperature, and composition on the surface morphology of Ni-Cr thin films grown on MgO(001) are studied by scanning tunneling microscopy and atomic force microscopy. We demonstrate that a combination of acid-etched substrates and high temperature deposition (400 °C) will result in smooth films with well-defined terraces (up to 30 nm wide) that are suitable for the study of progression of chemical reactions on the surface. Two different treatments are used to prepare the MgO substrates for deposition and they introduce characteristic differences in film surface morphology. Thin films that are grown on the phosphoric acid-treated substrates present reduced nucleation density during the initial stages of film growth which results in long and wide terraces. Due to the ≈16% lattice mismatch in the Ni(001)/MgO(001) system, film growth at 400 °C yields discontinuous films and a two-step growth process is necessary to obtain a continuous layer. Ni films are deposited at 100 °C and subjected to a post-growth annealing at 300 °C for 2 h to obtain a smoother surface. The addition of just 5 wt. % Cr drastically changes the film growth processes and yields continuous films at 400 °C without de-wetting in contrast to pure Ni films. With increasing Cr content, the films become progressively smoother with wider terraces. Ni5Cr alloy thin films have an rms surface roughness of 3.63 ± 0.75 nm, while Ni33Cr thin film is smoother with an rms roughness of only 0.29 ± 0.13 nm. The changes in film growth initiated by alloying with Cr are due to changes in the interfacial chemistry which favorably alters the initial adsorption of the metal atoms on MgO surface and suggests a reduction of the Ehrlich-Schwoebel barrier. The growth of smooth Ni-Cr thin films with a well-defined surface structure opens up a new pathway for a wide range of surface science studies related to alloy performance.

  5. Composition

    DEFF Research Database (Denmark)

    2014-01-01

    Memory Pieces are open compositions to be realised solo by an improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them...

  6. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2010-01-01

    New Year is an open composition to be realised by improvising musicians. It is included in "From the Danish Seasons" (see under this title). See more about my composition practise in the entry "Composition - General Introduction". This work is licensed under a Creative Commons "by-nc" License. You...

  7. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2011-01-01

    Strategies are open compositions to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound files will in some cases only provide a few minutes' sample. Please DOWNLOAD them to hear them in full...

  8. Nanocrystallization of amorphous M-Si thin film composites (M=Cr, Mn) and their thermoelectric properties

    Science.gov (United States)

    Burkov, A. T.; Novikov, S. V.; Schumann, J.

    2012-06-01

    We report on electrical resistivity and thermoelectric power of Cr-Si and Mn-Si composite films at temperatures from 300 K to 1000 K. The films were deposited on unheated Si/SiO2 substrates by magnetron sputtering from composite targets. The as-deposited films have amorphous structure. We use annealing with in-situ transport properties measurements to transform the films into nanocrystalline state with continuous monitoring their state. Nanocrystallization is considered as a promising way to improve thermoelectric efficiency, primarily due to reduction of lattice thermal conductivity κ. Among variety of methods for fabrication of NC materials, crystallization from amorphous state has features which are crucially important with respect to their electronic transport properties: since the crystallites and their interfaces are formed in this method via solid state reaction, the NC samples are dense and the interfaces are clean. This removes additional factors affecting properties of a nanocrystalline composite, such as contamination of nanocrystal interfaces by elements from environment or nanocrystal lattice distortion during nanocrystallization. Depending on the initial film composition, the films are transformed during annealing into single phase or multi-phase nanocrystalline composites with average grain size of 10 nm to 20 nm. We study the crystallization kinetics, stability of amorphous and nanocrystalline state and relation between electronic transport properties and structural state of the composites.

  9. Structural, chemical and optical properties of the polyethylene–copper sulfide composite thin films synthesized using polythionic acid as sulfur source

    Energy Technology Data Exchange (ETDEWEB)

    Ancutiene, Ingrida [Department of Physical and Inorganic Chemistry, Kaunas University of Technology, Radvilenu st. 19, LT-50254 Kaunas (Lithuania); Navea, Juan G. [Chemistry Department, Skidmore College, 815N. Broadway, Saratoga Springs, NY 12866 (United States); Baltrusaitis, Jonas, E-mail: job314@lehigh.edu [Department of Chemical and Biomolecular Engineering, Lehigh University, B336 Iacocca Hall, 111 Research Drive, Bethlehem, PA 18015 (United States)

    2015-08-30

    Graphical abstract: Several crystalline copper sulfide phases (spionkopite, anilite, digenite, djurleite, chalcocite) were obtained in as synthesized samples (PE-Cu{sub x}S) and elucidated using XRD. Thickness of the films obtained ranged from several microns to ∼18 μm and depended on the Cu(II/I) exposure time. Bandgap of the materials obtained was measured and ranged from 1.88 to 1.17 eV. Importantly, heating samples, many copper sulfide crystalline phase containing films at 100 °C in inert atmosphere invariably resulted in a single copper sulfide, anilite (Cu{sub 1.75}S), phase. - Highlights: • We investigated deposition of a single phase copper sulfide on polyethylene. • A single sulfur precursor – H{sub 2}S{sub 33}O{sub 6} – was used. • Increasing exposure time to Cu(II/I) yielded Cu{sub x}S with higher x values. • Heating at 100 °C in N{sub 2} resulted in a single anilite (Cu{sub 1.75}S) phase. • Cu(I) and Cu(II) compounds were detected using XPS. - Abstract: Synthesis and properties of thin copper sulfide films deposited on polyethylene were explored for the development of low cost hybrid organic–inorganic photovoltaic materials. Polyethylene was used as a model organic host material for thin copper sulfide film formation. Adsorption–diffusion method was used which utilized consecutive exposure of polyethylene to polythionic acid followed by aqueous Cu(II/I) solution. Several crystalline copper sulfide phases were obtained in synthesized samples and elucidated using X-ray diffraction. Surface chemical composition determined using X-ray photoelectron spectroscopy showed the presence of copper sulfides in combination with copper hydroxide. Thickness of the composite material films ranged from several microns to ∼18 μm and depended on the Cu(II/I) exposure time. Bandgap of the materials obtained was measured and ranged from 1.88 to 1.17 eV. Importantly, heating these complex copper sulfide crystalline phase containing films at 100

  10. Synthesis and characterization of MoO3–WO3 composite thin films by liquid phase deposition technique: Investigation of its photochromic properties

    Indian Academy of Sciences (India)

    H M Farveez Ahmed; Noor Shahina Begum

    2013-02-01

    In order to achieve high colouration efficiency, MoO3–WO3 composite thin films have been successfully deposited on sodium silicate glass and silicon wafer (111) at 30 °C by a very simple novel wet process known as liquid phase deposition. The deposited films were annealed at different temperatures and characterized by carrying out SEM, EDAX, UV-vis and XRD analyses. The EDAX and SEM analyses support the structure and existence of peaks corresponding to Mo, W and O. X-ray diffraction studies showed that MoO3–WO3 is amorphous at lower temperature and turns crystalline at higher annealing temperature and suggested the mixture of two crystalline phases such as orthorhombic–monoclinic. Photochromic properties of the MoO3–WO3 composite films were studied in the spectral region 400–1200 nm by illuminating them in polychromatic light. The photochromic behaviour is observed to be more effective in composites films in visible region.

  11. Simulation and experimental study on compositional evolution of Li-Co in LiCoO2 thin films during sputter deposition

    Science.gov (United States)

    Nimisha, C. S.; Mohan Rao, G.

    2011-06-01

    The compositional evolution in sputter deposited LiCoO2 thin films is influenced by process parameters involved during deposition. The electrochemical performance of these films strongly depends on their microstructure, preferential orientation and stoichiometry. The transport process of sputtered Li and Co atoms from the LiCoO2 target to the substrate, through Ar plasma in a planar magnetron configuration, was investigated based on the Monte Carlo technique. The effect of sputtering gas pressure and the substrate-target distance (dst) on Li/Co ratio, as well as, energy and angular distribution of sputtered atoms on the substrate were examined. Stable Li/Co ratios have been obtained at 5 Pa pressure and dst in the range 5-11 cm. The kinetic energy and incident angular distribution of Li and Co atoms reaching the substrate have been found to be dependent on sputtering pressure. Simulations were extended to predict compositional variations in films prepared at various process conditions. These results were compared with the composition of films determined experimentally using x-ray photoelectron spectroscopy (XPS). Li/Co ratio calculated using XPS was in moderate agreement with that of the simulated value. The measured film thickness followed the same trend as predicted by simulation. These studies are shown to be useful in understanding the complexities in multicomponent sputtering.

  12. Highly sensitive room temperature organic vapor sensor based on polybenzoxazine-derived carbon aerogel thin film composite

    Energy Technology Data Exchange (ETDEWEB)

    Thubsuang, Uthen [Materials Science and Engineering, School of Engineering and Resources, Walailak University, Nakhon Si Thammarat 80160 (Thailand); Sukanan, Darunee [The Petroleum and Petrochemical College and the Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Bangkok 10330 (Thailand); Sahasithiwat, Somboon [National Metal and Materials Technology Center, Thailand Science Park (TSP), Khlong Luang, Pathum Thani 12120 (Thailand); Wongkasemjit, Sujitra [The Petroleum and Petrochemical College and the Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Bangkok 10330 (Thailand); Chaisuwan, Thanyalak, E-mail: thanyalak.c@chula.ac.th [The Petroleum and Petrochemical College and the Center of Excellence on Petrochemical and Materials Technology, Chulalongkorn University, Bangkok 10330 (Thailand)

    2015-10-15

    Graphical abstract: - Highlights: • Activated carbon aerogel with high surface area can be prepared from polybenzoxazine. • Activated carbon aerogel enhances the adsorption capacity of gas sensor. • Organic vapors with very low concentration can be detected by the as-prepared sensor. • The as-prepared sensor shows impressive short exposure and recovery time. • The response to different organic vapors can be tailored by changing polymer matrix. - Abstract: Gas sensing composites were fabricated using polybenzoxazine-based activated carbon aerogel as a conductive filler. The activated carbon aerogel is a nano-porous material, which has high pore volume of 0.57 cm{sup 3}/g and surface area of 917 m{sup 2}/g. The activated carbon aerogel/polybutadiene composite displayed good response of 11.2 and 6.7 to toluene and n-hexane, respectively, compared to those of graphite/polybutadiene composite. The activated carbon aerogel/polybutadiene composite also showed high sensitivity of 3.09 × 10{sup 2} ppm{sup −1} to toluene. However, the sensitivity of activated carbon aerogel/polybutadiene composite drastically decreased to 1.99 ppm{sup −1} and zero when exposed to acetone and water, respectively. Contrarily, when polyvinyl alcohol was used as a matrix, the sensitivity was about 4.19 ppm{sup −1} to water. While the composite was found to be not sensitive to toluene. The activated carbon aerogel/polybutadiene composite also showed good recovery as the electrical resistance came back to the original value within minutes when exposed to nitrogen gas.

  13. Investigation of Structural, Compositional and Anti-Microbial Properties of Copper Thin Film Using Direct Current Magnetron Sputtering for Surgical Instruments

    Science.gov (United States)

    Kalaiselvam, S.; Sandhya, J.; Krishnan, K. V. Hari; Kedharnath, A.; Arulkumar, G.; Roseline, A. Ameelia

    Surgical instruments and other bioimplant devices, owing to their importance in the biomedical industry require high biocompatibility to be used in the human body. Nevertheless, issues of compatibility, bacterial infections are quite common in such devices. Hence development of surface coatings on various substrates for implant applications is a promising technique to combat the issues arising in these implant materials. The present investigation aims at coating copper on stainless steel substrate using DC Magnetron sputtering which is used to achieve film of required thickness (0.5-8μm). The deposition pressure, substrate temperature, power supply, distance between the specimen and target are optimized and maintained constant, while the sputtering time (30-110min) is varied. The sputtered copper thin film’s morphology, composition are characterized by SEM and EDAX. X-ray diffraction analysis shows copper oriented on (111) and (002) and copper oxide on (111) planes. The contact angle of copper thin film is 92∘ while AISI 316L shows 73∘. The antimicrobial studies carried in Staphylococcus aureus, Escherichia Coli, Klebsiella pneumonia and Candida albicans show that the maximum reduction was seen upto 35, 26, 54, 39CFU/mL, respectively after 24h. The cell viability is studied by MTT assay test on Vero cell line for 24h, 48h and 72h and average cell viability is 43.85%. The copper release from the thin film to the culture medium is 6691μg/L (maximum) is estimated from AAS studies. The copper coated substrate does not show much reaction with living Vero cells whereas the bacteria and fungi are found to be destroyed.

  14. Fabrication of titania thin film with composite nanostructure and its ability to photodegrade rhodamine B in water

    Institute of Scientific and Technical Information of China (English)

    Gaojie ZHANG; Jinming WU; Shaoguang LIU; Mi YAN

    2008-01-01

    A titania nanorod film was synthesized by direct oxidation of metallic Ti with hydrogen peroxide solution under a low temperature. Titania nanoparticles were then filled into the gaps among the nanorods through an infiltration sol-gel procedure to form a composite titania film with an ordered nanostructure. X-ray diffraction spectra indicate that the composite film was a mixture of anatase and rutile while the titania film obtained by only using a sol-gel procedure was pure anatase. Field emission scanning electron microscopy observations show that titania nanoparticles were embedded into the titania nanorod film. Photoluminescence spectra suggest the enhanced separation of electron and hole pairs for the obtained composite titania film over the corresponding titania nanorod film. The composite titania film exhibited improved ability to photodegrade rhodamine B in water compared with the titania nanorod film. The apparent photodegradation rate constant, fitting a pseudo-first-order, was 3 times of that obtained by the sol-gel derived titania film at the same weight. The improved photocata-lytic activity for the composite titania film could be attributed to the enhanced separation of electron and hole pairs due to the embedding of the titania nanoparticles within the titania nanorods.

  15. Complementary use of ion beam elastic backscattering and recoil detection analysis for the precise determination of the composition of thin films made of light elements

    Energy Technology Data Exchange (ETDEWEB)

    Climent-Font, A. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain)], E-mail: acf@uam.es; Cervera, M.; Hernandez, M.J. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Laboratorio de Microelectronica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Munoz-Martin, A. [Centro de Micro-Analisis de Materiales (CMAM), Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Piqueras, J. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain); Laboratorio de Microelectronica, Facultad de Ciencias, Universidad Autonoma de Madrid, Cantoblanco 28049, Madrid (Spain)

    2008-04-15

    Rutherford backscattering spectrometry (RBS) is a well known powerful technique to obtain depth profiles of the constituent elements in a thin film deposited on a substrate made of lighter elements. In its standard use the probing beam is typically 2 MeV He. Its capabilities to obtain precise composition profiles are severely diminished when the overlaying film is made of elements lighter than the substrate. In this situation the analysis of the energy of the recoiled element from the sample in the elastic scattering event, the ERDA technique may be advantageous. For the detection of light elements it is also possible to use beams at specific energies producing elastic resonances with these light elements to be analyzed, with a much higher scattering cross sections than the Rutherford values. This technique may be called non-RBS. In this work we report on the complementary use of ERDA with a 30 MeV Cl beam and non-RBS with 1756 keV H ions to characterize thin films made of boron, carbon and nitrogen (BCN) deposited on Si substrates.

  16. Shrink tape technique for heat-forming aluminum substrates for thin foil x-ray mirrors and the Neutron Star Interior Composition Explorer x-ray concentrators

    Science.gov (United States)

    Balsamo, Erin; Gendreau, Keith; Okajima, Takashi; Soong, Yang; Serlemitsos, Peter; Jalota, Lalit; Kenyon, Steven; Spartana, Nicholas; Fickau, David; Koenecke, Richard

    2016-01-01

    Consistent improvements in the design and fabrication of thin-foil, epoxy-replicated x-ray mirrors for astronomical telescopes have yielded increasingly higher quality and more precise astrophysical data. The Neutron Star Interior Composition Explorer (NICER) x-ray timing mission optics continues this tradition and introduces design elements that promise even more accurate measurements and precise astrophysical parameters. The singly reflecting concentrators have a curved axial profile to improve photon concentration and a sturdy full shell structure for enhanced module stability. These design elements introduced the challenge of reliably forming mirror substrates at an acceptable production rate. By developing a technique using heat shrink tape to compress and conform thin aluminum mirror substrates to shaping mandrels, production rate improved with successful fabrication. The technique's efficiency was analyzed by measuring hundreds of substrate profiles postforming, performance testing completely assembled concentrators composed of every size substrate, and comparing the results to simulated fabrication scenarios. On average, the profiles were copied within 4.6±3.7%. These measurements and the overall success of NICER's optics, via ground calibration, have shown that the heat-shrink tape method is reliable, repeatable, and could be used in future missions to increase production rate and improve performance.

  17. Composite glycerol/graphite/aromatic acid matrices for thin-layer chromatography/matrix-assisted laser desorption/ionization mass spectrometry of heterocyclic compounds.

    Science.gov (United States)

    Esparza, Cesar; Borisov, R S; Varlamov, A V; Zaikin, V G

    2016-10-28

    New composite matrices have been suggested for the analysis of mixtures of different synthetic organic compounds (N-containing heterocycles and erectile dysfunction drugs) by thin layer chromatography/matrix-assisted laser desorption ionization time-of-flight mass spectrometry (TLC/MALDI-TOF). Different mixtures of classical MALDI matrices and graphite particles dispersed in glycerol were used for the registration of MALDI mass spectra directly from TLC plates after analytes separation. In most of cases, the mass spectra possessed [M+H](+) ions; however, for some analytes only [M+Na](+) and [M+K](+) ions were observed. These ions have been used to generate visualized TLC chromatograms. The described approach increases the desorption/ionization efficiencies of analytes separated by TLC, prevent spot blurring, simplifies and decrease time for sample preparation. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. The Transmission Modes and Losses of the Poled Nano-crystal and Polymer Composite PbTiO3/PEK-c Thin-film Waveguides

    Institute of Scientific and Technical Information of China (English)

    REN Quan; Yuk Tak Chow; YANG Xudong; LV Zenghai; YANG Hongliang; CHAN Hau Ping; CHU Pak Lim

    2007-01-01

    Composite thin films of PbTiO3 nano-crystals and high transparency polymer polyetherketone(PEK-c) for application of non-linear optical devices were prepared by spin coating. The size of PbTiO3 nano-crystals was estimated to be 30-40 nm using a transmission electron microscope. The refractive index and the mode propagation losses at 633 nm were measured using the prism coupling technique and improved photographic technique respectively. They were found to be 1.6545 and 2.00 dB cm-1 (fundamental mode),respectively. Moreover, it is observed that this loss is increased at higher mode indices.

  19. An approach to growth of Fe-Si multilayers with controlled composition profile-a way to exchange coupled thin films.

    Science.gov (United States)

    Gouralnik, A S; Pustovalov, E V; Lin, K-W; Chuvilin, A L; Chusovitina, S V; Dotsenko, S A; Cherednichenko, A I; Plotnikov, V S; Ivanov, V A; Belokon, V I; Tkachenko, I A; Galkin, N G

    2017-03-17

    The growth, composition and structure of sandwich structures (Fe-rich layer/Si-rich layer/Fe-rich silicide layer) grown on a Si(111) surface were studied by a few complementary microscopic and spectroscopic techniques with high spatial resolution. Intermixing at the Fe/Si and Si/Fe interfaces is demonstrated. Fe-rich layers grown directly on the Si(111) surface are crystalline and have abrupt but rough interfaces at both sides. The succeeding layers are disordered and their interfaces are fuzzy. The distributions of Fe and Si within the layers are laterally non-uniform. The reproducible fabrication of thin non-magnetic silicide spacers of predetermined thickness is demonstrated. Sandwich structures with such spacers exhibit exchange coupling between ferromagnetic Fe-rich layers.

  20. An Observation of Diamond-Shaped Particle Structure in a Soya Phosphatidylcohline and Bacteriorhodopsin Composite Langmuir Blodgett Film Fabricated by Multilayer Molecular Thin Film Method

    Science.gov (United States)

    Tsujiuchi, Y.; Makino, Y.

    A composite film of soya phosphatidylcohline (soya PC) and bacteriorhodopsin (BR) was fabricated by the multilayer molecular thin film method using fatty acid and lipid on a quartz substrate. Direct Force Microscopy (DFM), UV absorption spectra and IR absorption spectra of the film were characterized on the detail of surface structure of the film. The DFM data revealed that many rhombus (diamond-shaped) particles were observed in the film. The spectroscopic data exhibited the yield of M-intermediate of BR in the film. On our modelling of molecular configuration indicate that the coexistence of the strong inter-molecular interaction and the strong inter-molecular interaction between BR trimmers attributed to form the particles.

  1. Ion-modulated nonlinear electronic transport in carbon nanotube bundle/RbAg4I5 thin film composite nanostructures

    Science.gov (United States)

    Sun, Jia-Lin; Zhang, Wei; Wei, Jinquan; Gu, Bingfu

    2014-01-01

    We have explored the ion-modulated electronic transport properties of mixed ionic-electronic conductor (MIEC) composite nanostructures made of superionic conductor RbAg4I5 films and carbon nanotube (CNT) bundle spiderwebs. Our experimental and theoretical studies indicate that the formation of ion-electron bound states (IEBSs) leads to strong ion-electron interference effect and interesting electronic transport of CNT, such as nonlinear current-voltage (I-V) characteristics and novel temperature dependence of the current. With increasing temperature, the hybrid nanostructures show rich phases with different dependence of current on temperature, which is related to the structural phase transition of RbAg4I5 and the transition of dissociation of IEBSs. The ion-modulation of the electric conductivity in such MIEC composite nanostructures with great tunability has been used to design new ionic-electronic composite nano-devices with function like field effect transistor.

  2. Building up Graphene-Based Conductive Polymer Composite Thin Films Using Reduced Graphene Oxide Prepared by γ-Ray Irradiation

    Directory of Open Access Journals (Sweden)

    Siyuan Xie

    2013-01-01

    Full Text Available In this paper, reduced graphene oxide (RGO was prepared by means of γ-ray irradiation of graphene oxide (GO in a water/ethanol mix solution, and we investigated the influence of reaction parameters, including ethanol concentration, absorbed dose, and dose rate during the irradiation. Due to the good dispersibility of the RGO in the mix solution, we built up flexible and conductive composite films based on the RGO and polymeric matrix through facile vacuum filtration and polymer coating. The electrical and optical properties of the obtained composite films were tested, showing good electrical conductivity with visible transmittance but strong ultraviolet absorbance.

  3. Fabrication of composite thin films with microstructures of honeycomb, foam, and nanosphere arrays through adsorption and self-assembly of block copolymers at the liquid/liquid interface.

    Science.gov (United States)

    Liu, Yanan; Chen, Lifang; Geng, Yuanyuan; Lee, Yong-Ill; Li, Ying; Hao, Jingcheng; Liu, Hong-Guo

    2013-10-01

    The adsorption and self-organization behaviors of two kinds of block copolymers, polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) and poly(4-vinylpyridine)-block-polystyrene-block-poly(4-vinylpyridine) (P4VP-b-PS-b-P4VP), at planar liquid/liquid interfaces were investigated. A gel film decorating with honeycomb-like microstructures forms at the liquid/liquid interface between PS-b-P4VP chloroform solution and chloroauric acid aqueous solution. However, foam films were developed when the chloroauric acid aqueous solution was replaced by a chloroplatinic acid solution or a silver nitrate solution. Furthermore, a free-standing film containing the ordered arrays of nanospheres appeared at the liquid/liquid interface between P4VP-b-PS-b-P4VP chloroform solution and chloroauric acid aqueous solution. The formation of these microstructures was attributed to the adsorption of polymer molecules, combining with inorganic ions and the self-assembly of the composite species at the interface. The doped metal ions and complex ions were transformed to metal nanoparticles after further treatment. This is a facile and convenient method to prepare polymer/inorganic nanoparticle composites. These results also indicate the great influences of the polymer structures and the inorganic species in the aqueous phases on the self-assembly behaviors of the polymers at the interfaces, the final morphology, and structure of the composites. In addition, the formed thin composite films doped with well-dispersed, homogeneous small noble metal nanoparticles exhibit great and durable catalytic activities for the reduction of 4-nitrophenol (4-NP) by potassium borohydride.

  4. Electrical dependence on the chemical composition of the gate dielectric in indium gallium zinc oxide thin-film transistors

    Science.gov (United States)

    Tari, Alireza; Lee, Czang-Ho; Wong, William S.

    2015-07-01

    Bottom-gate thin-film transistors were fabricated by depositing a 50 nm InGaZnO (IGZO) channel layer at 150 °C on three separate gate dielectric films: (1) thermal SiO2, (2) plasma-enhanced chemical-vapor deposition (PECVD) SiNx, and (3) a PECVD SiOx/SiNx dual-dielectric. X-ray photoelectron and photoluminescence spectroscopy showed the Vo concentration was dependent on the hydrogen concentration of the underlying dielectric film. IGZO films on SiNx (high Vo) and SiO2 (low Vo) had the highest and lowest conductivity, respectively. A PECVD SiOx/SiNx dual-dielectric layer was effective in suppressing hydrogen diffusion from the nitride layer into the IGZO and resulted in higher resistivity films.

  5. Synthesis of nanoparticle/ligand composite thin films by sequential ligand self assembly and surface complex reduction.

    Science.gov (United States)

    Muench, Falk; Fuchs, Anne; Mankel, Eric; Rauber, Markus; Lauterbach, Stefan; Kleebe, Hans-Joachim; Ensinger, Wolfgang

    2013-01-01

    Nanocomposite thin films consisting of ligand-connected metal nanoparticles were deposited by iteration of ligand assembly, surface complex formation and reduction. This novel and convenient approach combines characteristics of the layer-by-layer (LbL) and the successive ion layer adsorption and reaction (SILAR) techniques. In contrast to classical LbL assembly, the nanoparticle formation is performed in situ, avoiding separate reduction, protection and attachment steps. To demonstrate the versatility of the approach, different metal precursors (Pd, Ag and Au salts) and linkers (1,2-ethanedithiol, 1,4-benzenedithiol and polythiol) were applied. The formation of dithiol-linked nanoparticle films was confirmed by TEM and XPS. By combining the deposition protocol with ion track etched polycarbonate templates, nanotubes and nanowires with high aspect ratios of up to 300 could be fabricated.

  6. Structure and composition of magnetocaloric Ni-Mn-In-Co thin films on the nanoscale - a TEM study

    Energy Technology Data Exchange (ETDEWEB)

    Erkartal, Burak; Schuermann, Ulrich; Kienle, Lorenz [Institute for Materials Science, Synthesis and Real Structure, Christian Albrechts University, Kiel (Germany); Duppel, Viola [Nanochemistry Max Planck Institute for Solid State Research, Stuttgart (Germany); Niemann, Robert; Schultz, Ludwig; Faehler, Sebastian [IFW Dresden (Germany)

    2012-08-15

    A complementary set of electron microscopy techniques is applied for the determination of structural and chemical segregation phenomena within a 300 nm thick metamagnetic Ni-Mn-In-Co thin film. The structure is predominantly composed of distinct modulated martensites of the 5M-, 6M-, 7M-, and 8M-type. Additionally these modulated structures exhibit twinning and stacking disordering. The nature of the disordering and the structural misfit at the twin interface were analyzed via high resolution micrographs. Next to an adhesion layer of Cr interdiffusion on the nanoscale was observed producing a penternary chemically and structurally homogeneous precipitate. The structure can be assigned to a twinned non-modulated pseudocubic model. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Microscopic origin of perpendicular magnetic anisotropy in amorphous Nd-Co homogeneous and compositionally modulated, thin films studied by XMCD

    Energy Technology Data Exchange (ETDEWEB)

    Cid, R; Diaz, J; Alvarez-Prado, L M; Alameda, J M [Dpto. Fisica, Facultad de Ciencias, Universidad de Oviedo - CINN, C/ Calvo Sotelo s/n, 33007 Oviedo (Spain); Valvidares, S M; Cezar, J C; Brookes, N B, E-mail: cidrosalia.uo@uniovi.e [European Synchrotron Radiation Facility, 6 Rue Jules Horowitz, BP220, 38043 (France)

    2010-01-01

    Amorphous Nd-Co films deposited by DC-magnetron sputtering presented perpendicular magnetic anisotropy (PMA) with energies, K{sub N}, of the order of 10{sup 6} erg/cc at RT. To understand the origin of their PMA, we measured the orbital and spin magnetic moments in Co and Nd by XMCD at the Co L{sub 3,2} and Nd M{sub 5,4} edges in two kinds of samples of similar thickness (30 nm) and composition: one compositionally modulated Nd/Co film (CM) with strong PMA (K{sub N} {approx}10{sup 7} erg/cc at 10 K) and a homogenous alloy (A) with not strong enough PMA to see stripe domains for such thickness. The XMCD analysis evidenced the significant role of Nd in the PMA of these films.

  8. Physical properties of nanostructured (PbSx(CuS1−x composite thin films grown by successive ionic layer adsorption and reaction method

    Directory of Open Access Journals (Sweden)

    A.U. Ubale

    2016-03-01

    Full Text Available Nanostructured ternary semiconducting (PbSx(CuS1−x thin films were grown on glass substrates by successive ionic layer adsorption and reaction (SILAR technique at room temperature. The structural, morphological and optical characterizations of the films were carried out by X-ray diffraction, scanning electron microscopy and UV–Vis spectrophotometer respectively. The structural studies revealed that, (PbSx(CuS1−x films are nanocrystalline in nature and have mixed phase of cubic PbS and hexagonal CuS. The optical absorption measurements showed that band gap energy of (PbSx(CuS1−x can be engineered between 2.57 and 2.28 eV by varying compositional parameter ‘x’. The room temperature dc dark electrical resistivity of PbS film is found to be 28.85 Ωcm and it decreases when content of Cu in composite increases and becomes 0.05 Ωcm for pure CuS. The thermo-emf measurements showed that the as deposited (PbSx(CuS1−x films are of n-type. The water angle contact measurements of (PbSx(CuS1−x, revealed that, films are hydrophilic in nature and it could be advantageous in electrochemical application.

  9. Autoclave processing for composite material fabrication. 1: An analysis of resin flows and fiber compactions for thin laminate

    Science.gov (United States)

    Hou, T. H.

    1985-01-01

    High quality long fiber reinforced composites, such as those used in aerospace and industrial applications, are commonly processed in autoclaves. An adequate resin flow model for the entire system (laminate/bleeder/breather), which provides a description of the time-dependent laminate consolidation process, is useful in predicting the loss of resin, heat transfer characteristics, fiber volume fraction and part dimension, etc., under a specified set of processing conditions. This could be accomplished by properly analyzing the flow patterns and pressure profiles inside the laminate during processing. A newly formulated resin flow model for composite prepreg lamination process is reported. This model considers viscous resin flows in both directions perpendicular and parallel to the composite plane. In the horizontal direction, a squeezing flow between two nonporous parallel plates is analyzed, while in the vertical direction, a poiseuille type pressure flow through porous media is assumed. Proper force and mass balances have been made and solved for the whole system. The effects of fiber-fiber interactions during lamination are included as well. The unique features of this analysis are: (1) the pressure gradient inside the laminate is assumed to be generated from squeezing action between two adjacent approaching fiber layers, and (2) the behavior of fiber bundles is simulated by a Finitely Extendable Nonlinear Elastic (FENE) spring.

  10. Composition

    DEFF Research Database (Denmark)

    Bergstrøm-Nielsen, Carl

    2014-01-01

    Cue Rondo is an open composition to be realised by improvising musicians. See more about my composition practise in the entry "Composition - General Introduction". Caution: streaming the sound/video files will in some cases only provide a few minutes' sample, or the visuals will not appear at all....... Please DOWNLOAD them to see/hear them in full length! This work is licensed under a Creative Commons "by-nc" License. You may for non-commercial purposes use and distribute it, performance instructions as well as specially designated recordings, as long as the author is mentioned. Please see http...

  11. Fabrication and evaluation of thin layer PVDF composites using MWCNT reinforcement: Mechanical, electrical and enhanced electromagnetic interference shielding properties

    Directory of Open Access Journals (Sweden)

    B. V. Bhaskara Rao

    2016-06-01

    Full Text Available Radar X-band electromagnetic interference shielding (EMS is one of the prime requirements for any air vehicle coating; with limitations on the balance between strength and thickness of the EMS material. Nanocomposite of multiwalled-carbon-nanotubes (MWCNT has been homogeneously integrated (0 – 9 wt% with polymer, poly (vinylidene fluoride, PVDF to yield 300 micron film. The PVDF + 9 wt% MWCNT sample of density 1.41 g/cm3 show specific shielding effectiveness (SSE of 17.7 dB/(g/cm3 (99.6% EMS, with maintained hardness and improved conductivity. With multilayer stacking (900 microns of these films of density 1.37 g/cm3, the sample showed increase in SSE to 23.3 dB/(g/cm3 (99.93% EMS. Uniform dispersion of MWCNTs in the PVDF matrix gives rise to increased conductivity in the sample beyond 5 wt% MWCNT reinforcement. The results are correlated to the hardness, reflection loss, absorption loss, percolation threshold, permittivity and the conductivity data. An extremely thin film with maximum EMS property is hence proposed.

  12. An analytical model for shape memory alloy fiber-reinforced composite thin-walled beam undergoing large deflection

    Directory of Open Access Journals (Sweden)

    Yongsheng Ren

    2015-03-01

    Full Text Available The structural model of the thin-walled laminated beams with integral shape memory alloy active fibers and accounting for geometrically nonlinear is presented in this article. The structural modeling is split into two parts: a two-dimensional analysis over the cross section and a geometrically nonlinear analysis of a beam along the beam span. The variational asymptotic method is used to formulate the force–deformation relationship equations taking into account the presence of active shape memory alloy fibers distributed along the cross section of the beam. The geometrically nonlinear governing equations are derived using variational principle and based on the von Kármán-type nonlinear strain–displacement relations. The equations are then solved using Galerkin’s method and an incremental Newton–Raphson method. The validation for the proposed model has been carried out by comparison of the present results with those available in the literature. The results show that significant extension, bending, and twisting coupled nonlinear deflections occur during the phase transformation due to shape memory alloy actuation. The effects of the volume fraction of the shape memory alloy fiber and ply angle are also addressed.

  13. Electrical dependence on the chemical composition of the gate dielectric in indium gallium zinc oxide thin-film transistors

    Energy Technology Data Exchange (ETDEWEB)

    Tari, Alireza, E-mail: atari@uwaterloo.ca; Lee, Czang-Ho; Wong, William S. [Department of Electrical and Computer Engineering, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada)

    2015-07-13

    Bottom-gate thin-film transistors were fabricated by depositing a 50 nm InGaZnO (IGZO) channel layer at 150 °C on three separate gate dielectric films: (1) thermal SiO{sub 2}, (2) plasma-enhanced chemical-vapor deposition (PECVD) SiN{sub x}, and (3) a PECVD SiO{sub x}/SiN{sub x} dual-dielectric. X-ray photoelectron and photoluminescence spectroscopy showed the V{sub o} concentration was dependent on the hydrogen concentration of the underlying dielectric film. IGZO films on SiN{sub x} (high V{sub o}) and SiO{sub 2} (low V{sub o}) had the highest and lowest conductivity, respectively. A PECVD SiO{sub x}/SiN{sub x} dual-dielectric layer was effective in suppressing hydrogen diffusion from the nitride layer into the IGZO and resulted in higher resistivity films.

  14. Preparation of Thin Palladium Composite Membranes and Application to Hydrogen/Nitrogen Separation%钯复合膜的制备及其存氢气氮气分离中的应用

    Institute of Scientific and Technical Information of China (English)

    张科; 高会元; 芮泽宝; 林跃生; 李永丹

    2007-01-01

    Thin palladium composite membranes were prepared by modified electroless plating method on α-alumina supports and a dense Pd/α-Al2O3 composite membrane with high hydrogen flux, good selectivity for hydrogen was obtained. It was tested in a single gas permeation system for hydrogen permeance and hydrogen selectivity over nitrogen. The hydrogen permeance of the corresponding membrane was as high as 2.45×10-6 mol·m-2·s-1·Pa-1 and H2/N2 selectivity over 700 at 623K and a pressure difference of 0.1MPa. The main resistance of the composite membrane to H2 permeation lies in the aluminum ceramic support rather than the thin Pd layer.

  15. High Performance Thin-film Composite Membranes with Mesh-Reinforced Hydrophilic Sulfonated Polyphenylenesulfone (sPPSU) Substrates for Osmotically Driven Processes

    KAUST Repository

    Han, Gang

    2015-12-17

    We have for the first time combined the strength of hydrophilic sulfonated material and thin woven open-mesh via a continuous casting process to fabricate mesh-reinforced ultrafiltration (UF) membrane substrates with desirable structure and morphology for the development of high-performance thin-film composite (TFC) osmosis membranes. A new sulfonated polyphenylenesulfone (sPPSU) polymer with super-hydrophilic nature is used as the substrate material, while a hydrophilic polyester (PET) open-mesh with a small thickness of 45 μm and an open area of 44.5% is employed as the reinforcing fabric during membrane casting. The newly developed sPPSU-TFC membranes not only exhibit a fully sponge-like cross-section morphology, but also possess excellent water permeability (A=3.4–3.7 L m−2 h−1 bar−1) and selectivity toward NaCl (B=0.10–0.23 L m−2 h−1). Due to the hydrophilic nature and low membrane thickness of 53–67 μm, the PET-woven reinforced sPPSU substrates have remarkably small structural parameters (S) of less than 300 μm. The sPPSU-TFC membranes thereby display impressive water fluxes (Jw) of 69.3–76.5 L m−2 h−1 and 38.7–47.0 L m−2 h−1 against a deionized water feed using 2 M NaCl as the draw solution under pressure retarded osmosis (PRO) and forward osmosis (FO) modes, respectively. This performance surpasses the state-of-the-art commercially available FO membranes. The sPPSU-TFC membranes also show exciting performance for synthetic seawater (3.5 wt% NaCl) desalination and water reclamation from real municipal wastewater. The newly developed PET-woven sPPSU-TFC membranes may have great potential to become a new generation membrane for osmotically driven processes.

  16. Chemical structure and composition of CHN thin films%CHN薄膜化学结构和成分分析

    Institute of Scientific and Technical Information of China (English)

    李建根; 吴卫东; 干泰原; 曹林洪

    2011-01-01

    The amorphous CHN thin films were prepared via external capacitive coupling LPPCVD (low pressure plasma chemical vapor deposition). X-ray photoelectron spectroscopy(XPS) showed that with the increase of N2/CH4 ratio, the content of N in the film increases gradually. The C-N covalent bond existed in the film was also discussed. The fourier transform infrared spectroscopy (FTIR) indicated the existence of C-N chemical bond and other functional groups. The Raman spectrum showed that the central positions of D peak and G peak approach after separation, and the area ratio of D peak to G peak increases with the increase of N2/CH4 ratio for that the degree of disorder of the film increases and the film tends to be graphitization.%采用外置式电容耦合低压等离子化学气相沉积法制备非晶CHN薄膜.X射线光电子能谱仪分析表明薄膜表面C、N和O的相对含量比,同时随着N2/CH4比例增大,薄膜中N元素的含量逐渐增加;并且对薄膜中存在的C-N共价键进行了讨论;傅里叶红外透射光谱分析表明薄膜中存在C-N键和其他官能团;拉曼光谱分析表明随着N2/CH4比例增大,D峰和G峰的中心位置先远离然后靠近,并且D峰和G峰的面积比逐渐增加,源于薄膜无序度增加且逐渐趋于石墨化.

  17. Fabrication and characterization of Al2O3 /Si composite nanodome structures for high efficiency crystalline Si thin film solar cells

    Science.gov (United States)

    Zhang, Ruiying; Zhu, Jian; Zhang, Zhen; Wang, Yanyan; Qiu, Bocang; Liu, Xuehua; Zhang, Jinping; Zhang, Yi; Fang, Qi; Ren, Zhong; Bai, Yu

    2015-12-01

    We report on our fabrication and characterization of Al2O3/Si composite nanodome (CND) structures, which is composed of Si nanodome structures with a conformal cladding Al2O3 layer to evaluate its optical and electrical performance when it is applied to thin film solar cells. It has been observed that by application of Al2O3thin film coating using atomic layer deposition (ALD) to the Si nanodome structures, both optical and electrical performances are greatly improved. The reflectivity of less than 3% over the wavelength range of from 200 nm to 2000 nm at an incident angle from 0° to 45° is achieved when the Al2O3 film is 90 nm thick. The ultimate efficiency of around 27% is obtained on the CND textured 2 μm-thick Si solar cells, which is compared to the efficiency of around 25.75% and 15% for the 2 μm-thick Si nanodome surface-decorated and planar samples respectively. Electrical characterization was made by using CND-decorated MOS devices to measure device's leakage current and capacitance dispersion. It is found the electrical performance is sensitive to the thickness of the Al2O3 film, and the performance is remarkably improved when the dielectric layer thickness is 90 nm thick. The leakage current, which is less than 4x10-9 A/cm2 over voltage range of from -3 V to 3 V, is reduced by several orders of magnitude. C-V measurements also shows as small as 0.3% of variation in the capacitance over the frequency range from 10 kHz to 500 kHz, which is a strong indication of surface states being fully passivated. TEM examination of CND-decorated samples also reveals the occurrence of SiOx layer formed between the interface of Si and the Al2O3 film, which is thin enough that ensures the presence of field-effect passivation, From our theoretical and experimental study, we believe Al2O3 coated CND structures is a truly viable approach to achieving higher device efficiency.

  18. Fabrication and characterization of Al{sub 2}O{sub 3} /Si composite nanodome structures for high efficiency crystalline Si thin film solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ruiying, E-mail: ryzhang2008@sinano.ac.cn [Key lab of nanodevices and applications, Chinese Academy of Sciences, Division of nano-devices and related materials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123 (China); State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, 865 Changning Road, Shanghai 200050 China (China); Zhu, Jian; Zhang, Zhen; Wang, Yanyan; Qiu, Bocang [Key lab of nanodevices and applications, Chinese Academy of Sciences, Division of nano-devices and related materials, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123 (China); Liu, Xuehua; Zhang, Jinping; Zhang, Yi [Platform for Characterization & Test, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Suzhou, 215123 (China); Fang, Qi; Ren, Zhong [Oxford Instruments Plasma Technology, Yatton, Bristol, BS49 4AP (United Kingdom); Bai, Yu [School of Nano-Science and Nano-Engineering, Xi’an Jiaotong University, Suzhou, 215123 (China)

    2015-12-15

    We report on our fabrication and characterization of Al{sub 2}O{sub 3}/Si composite nanodome (CND) structures, which is composed of Si nanodome structures with a conformal cladding Al{sub 2}O{sub 3} layer to evaluate its optical and electrical performance when it is applied to thin film solar cells. It has been observed that by application of Al{sub 2}O{sub 3}thin film coating using atomic layer deposition (ALD) to the Si nanodome structures, both optical and electrical performances are greatly improved. The reflectivity of less than 3% over the wavelength range of from 200 nm to 2000 nm at an incident angle from 0° to 45° is achieved when the Al{sub 2}O{sub 3} film is 90 nm thick. The ultimate efficiency of around 27% is obtained on the CND textured 2 μm-thick Si solar cells, which is compared to the efficiency of around 25.75% and 15% for the 2 μm-thick Si nanodome surface-decorated and planar samples respectively. Electrical characterization was made by using CND-decorated MOS devices to measure device’s leakage current and capacitance dispersion. It is found the electrical performance is sensitive to the thickness of the Al{sub 2}O{sub 3} film, and the performance is remarkably improved when the dielectric layer thickness is 90 nm thick. The leakage current, which is less than 4x10{sup −9} A/cm{sup 2} over voltage range of from -3 V to 3 V, is reduced by several orders of magnitude. C-V measurements also shows as small as 0.3% of variation in the capacitance over the frequency range from 10 kHz to 500 kHz, which is a strong indication of surface states being fully passivated. TEM examination of CND-decorated samples also reveals the occurrence of SiO{sub x} layer formed between the interface of Si and the Al{sub 2}O{sub 3} film, which is thin enough that ensures the presence of field-effect passivation, From our theoretical and experimental study, we believe Al{sub 2}O{sub 3} coated CND structures is a truly viable approach to achieving higher device

  19. Fabrication and characterization of Al2O3 /Si composite nanodome structures for high efficiency crystalline Si thin film solar cells

    Directory of Open Access Journals (Sweden)

    Ruiying Zhang

    2015-12-01

    Full Text Available We report on our fabrication and characterization of Al2O3/Si composite nanodome (CND structures, which is composed of Si nanodome structures with a conformal cladding Al2O3 layer to evaluate its optical and electrical performance when it is applied to thin film solar cells. It has been observed that by application of Al2O3thin film coating using atomic layer deposition (ALD to the Si nanodome structures, both optical and electrical performances are greatly improved. The reflectivity of less than 3% over the wavelength range of from 200 nm to 2000 nm at an incident angle from 0° to 45° is achieved when the Al2O3 film is 90 nm thick. The ultimate efficiency of around 27% is obtained on the CND textured 2 μm-thick Si solar cells, which is compared to the efficiency of around 25.75% and 15% for the 2 μm-thick Si nanodome surface-decorated and planar samples respectively. Electrical characterization was made by using CND-decorated MOS devices to measure device’s leakage current and capacitance dispersion. It is found the electrical performance is sensitive to the thickness of the Al2O3 film, and the performance is remarkably improved when the dielectric layer thickness is 90 nm thick. The leakage current, which is less than 4x10−9 A/cm2 over voltage range of from -3 V to 3 V, is reduced by several orders of magnitude. C-V measurements also shows as small as 0.3% of variation in the capacitance over the frequency range from 10 kHz to 500 kHz, which is a strong indication of surface states being fully passivated. TEM examination of CND-decorated samples also reveals the occurrence of SiOx layer formed between the interface of Si and the Al2O3 film, which is thin enough that ensures the presence of field-effect passivation, From our theoretical and experimental study, we believe Al2O3 coated CND structures is a truly viable approach to achieving higher device efficiency.

  20. Low-temperature oxidizing plasma surface modification and composite polymer thin-film fabrication techniques for tailoring the composition and behavior of polymer surfaces

    Science.gov (United States)

    Tompkins, Brendan D.

    This dissertation examines methods for modifying the composition and behavior of polymer material surfaces. This is accomplished using (1) low-temperature low-density oxidizing plasmas to etch and implant new functionality on polymers, and (2) plasma enhanced chemical vapor deposition (PECVD) techniques to fabricate composite polymer materials. Emphases are placed on the structure of modified polymer surfaces, the evolution of polymer surfaces after treatment, and the species responsible for modifying polymers during plasma processing. H2O vapor plasma modification of high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polycarbonate (PC), and 75A polyurethane (PU) was examined to further our understanding of polymer surface reorganization leading to hydrophobic recovery. Water contact angles (wCA) measurements showed that PP and PS were the most susceptible to hydrophobic recovery, while PC and HDPE were the most stable. X-ray photoelectron spectroscopy (XPS) revealed a significant quantity of polar functional groups on the surface of all treated polymer samples. Shifts in the C1s binding energies (BE) with sample age were measured on PP and PS, revealing that surface reorganization was responsible for hydrophobic recovery on these materials. Differential scanning calorimetry (DSC) was used to rule out the intrinsic thermal properties as the cause of reorganization and hydrophobic recovery on HDPE, LDPE, and PP. The different contributions that polymer cross-linking and chain scission mechanisms make to polymer aging effects are considered. The H2O plasma treatment technique was extended to the modification of 0.2 microm and 3.0 microm track-etched polycarbonate (PC-TE) and track-etched polyethylene terephthalate (PET-TE) membranes with the goal of permanently increasing the hydrophilicity of the membrane surfaces. Contact angle measurements on freshly treated and aged samples confirmed the wettability of the

  1. Effect of radio frequency power on composition, structure and optical properties of MoSe{sub x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Li-ping, E-mail: lpfeng@nwpu.edu.cn; Li, Ning; Liu, Zhengtang

    2014-07-01

    MoSe{sub x} films were prepared by radio frequency (RF) magnetron sputtering under various RF powers in the range of 40–130 W. Effects of RF power on composition, structure and optical properties of MoSe{sub x} films were investigated. Results show that the chemical bonding, binding energy, structure, and optical properties of MoSe{sub x} films depend greatly on RF power. When the RF power varies from 40 to 70 W, the bonding atomic ratio of Se/Mo in MoSe{sub x} films increase and Mo 3d{sub 5/2} and Se 3d{sub 5/2} peaks shift towards lower binding energies. With further increase in the RF power from 70 to 130 W, the bonding atomic ratio of Se/Mo in MoSe{sub x} films decreases and Mo 3d{sub 5/2} and Se 3d{sub 5/2} peaks move to higher binding energies. Structures of MoSe{sub x} films are amorphous with the RF power ≤70 W, whereas structures of MoSe{sub x} films exhibit nanostructure with the RF power >70 W. Moreover, MoSe{sub x} films deposited at 70 W have larger refractive index, lower extinction coefficient, and higher band gap than those deposited at other RF power.

  2. Crystal structure and composition of BAlN thin films: Effect of boron concentration in the gas flow

    Science.gov (United States)

    Wang, Shuo; Li, Xiaohang; Fischer, Alec M.; Detchprohm, Theeradetch; Dupuis, Russell D.; Ponce, Fernando A.

    2017-10-01

    We have investigated the microstructure of BxAl1-xN films grown by flow-modulated epitaxy at 1010 °C, with B/(B + Al) gas-flow ratios ranging from 0.06 to 0.18. The boron content obtained from X-ray diffraction (XRD) patterns ranges from x = 0.02 to 0.09. On the other hand, boron content deduced from the aluminum signal in the Rutherford backscattering spectra (RBS) ranges from x = 0.06 to 0.16, closely following the gas-flow ratios. Transmission electron microscopy indicates the sole presence of a wurtzite crystal structure in the BAlN films, and a tendency towards columnar growth for B/(B + Al) gas-flow ratios below 0.12. For higher ratios, the BAlN films exhibit a tendency towards twin formation and finer microstructure. Electron energy loss spectroscopy has been used to profile spatial variations in the composition of the films. The RBS data suggest that the incorporation of B is highly efficient for our growth method, while the XRD data indicate that the epitaxial growth may be limited by a solubility limit in the crystal phase at about 9%, for the range of B/(B + Al) gas-flow ratios that we have studied, which is significantly higher than previously thought.

  3. Optical Gas Sensing of Ammonia and Amines Based on Protonated Porphyrin/TiO2 Composite Thin Films

    Science.gov (United States)

    Castillero, Pedro; Roales, Javier; Lopes-Costa, Tânia; Sánchez-Valencia, Juan R.; Barranco, Angel; González-Elipe, Agustín R.; Pedrosa, José M.

    2016-01-01

    Open porous and transparent microcolumnar structures of TiO2 prepared by physical vapour deposition in glancing angle configuration (GLAD-PVD) have been used as host matrices for two different fluorescent cationic porphyrins, 5-(N-methyl 4-pyridyl)-10,15,20-triphenyl porphine chloride (MMPyP) and meso-tetra (N-methyl 4-pyridyl) porphine tetrachloride (TMPyP). The porphyrins have been anchored by electrostatic interactions to the microcolumns by self-assembly through the dip-coating method. These porphyrin/TiO2 composites have been used as gas sensors for ammonia and amines through previous protonation of the porphyrin with HCl followed by subsequent exposure to the basic analyte. UV–vis absorption, emission, and time-resolved spectroscopies have been used to confirm the protonation–deprotonation of the two porphyrins and to follow their spectral changes in the presence of the analytes. The monocationic porphyrin has been found to be more sensible (up to 10 times) than its tetracationic counterpart. This result has been attributed to the different anchoring arrangements of the two porphyrins to the TiO2 surface and their different states of aggregation within the film. Finally, there was an observed decrease of the emission fluorescence intensity in consecutive cycles of exposure and recovery due to the formation of ammonium chloride inside the film. PMID:28025570

  4. Crystal structure and composition of BAlN thin films: Effect of boron concentration in the gas flow

    KAUST Repository

    Wang, Shuo

    2017-07-20

    We have investigated the microstructure of BxAl1-xN films grown by flow-modulated epitaxy at 1010 oC, with B/(B+Al) gas-flow ratios ranging from 0.06 to 0.18. The boron content obtained from X-ray diffraction (XRD) patterns ranges from x = 0.02 to 0.09. On the other hand, boron content deduced from the aluminum signal in the Rutherford backscattering spectra (RBS) ranges x = 0.06 to 0.16, closely following gas-flow ratios. Transmission electron microscopy indicates the sole presence of wurtzite crystal structure in the BAlN films, and a tendency towards columnar growth for B/(B+Al) gas-flow ratios below 0.12. For higher ratios, the BAlN films exhibit a tendency towards twin formation and finer microstructure. Electron energy loss spectroscopy has been used to profile spatial variations in the composition of the films.The RBS data suggest that the incorporation of B is highly efficient for our growth method, while the XRD data indicate that the epitaxial growth may be limited by a solubility limit in the crystal phase at about 9%, for the range of B/(B+Al) gas-flow ratios that we used, which is significantly higher than previously thought.

  5. Effects of bath composition on the morphology of electroless-plated Cu electrodes for hetero-junctions with intrinsic thin layer solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woon Young [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Lee, Yu Jin [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of); Department of Materials Science & Engineering, Yonsei University, Yonsei-ro 50, Seodaemun-Gu, Seoul 120-749 (Korea, Republic of); Lee, Min Hyung, E-mail: minhyung@kitech.re.kr [Surface Technology R& BD Group, Korea Institute of Industrial Technology (KITECH), Gaetbeol-ro 156, Yeonsu-gu, Incheon 406-840 (Korea, Republic of)

    2015-07-31

    The morphology of an electroless-plated Cu electrode was investigated as a function of bath composition. To enhance the selectivity of Cu electrode deposition on the surface of an indium tin oxide layer, a Ti/Cu multi-layer was deposited as a Cu electrode seed layer by physical vapor deposition, and then electroless plating was performed using various complexing agents and a surfactant. The degree of selectivity was effectively influenced by the type of complexing agent. The electroless plating solution containing N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine (THPED) as complexing agent showed excellent selective growth of the Cu electrode as compared to the solution containing ethylenediaminetetraacetic acid. Even though THPED led to better selective growth of the electroless-plated Cu electrode, the aspect ratio of electrode lateral growth was about 2.7 times that of vertical growth. By adding a nonionic surfactant, the ratio between vertical growth rate and lateral growth rate was improved about 4.6 times. The Cu–THPED electroless plating with nonionic surfactant provided a drastic decrease in lateral growth rate, compared with the Cu–THPED electroless plating bath excluding nonionic surfactant. The Cu–THPED solution including nonionic surfactant is a promising composition of electroless plating solution for the clear selective plating of Cu electrodes on hetero-junctions with intrinsic thin layer solar cells. - Highlights: • Selective electroless plating (SEP) depends on binding strength of complexing agent. • The SEP was performed using Cu-N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylenediamine. • A surfactant is able to remove hydrogen bubbles on Cu electrode surface. • The growth of Cu electrode was improved in vertical direction by adding surfactant.

  6. Robust outer-selective thin-film composite polyethersulfone hollow fiber membranes with low reverse salt flux for renewable salinity-gradient energy generation

    KAUST Repository

    Cheng, Zhen Lei

    2016-01-08

    This study reports outer-selective thin-film composite (TFC) hollow fiber membranes with extremely low reverse salt fluxes and robustness for harvesting salinity-gradient energy from pressure retarded osmosis (PRO) processes. Almost defect-free polyamide layers with impressive low salt permeabilities were synthesized on top of robust polyethersulfone porous supports. The newly developed TFC-II membrane shows a maximum power density of 7.81 W m−2 using 1 M NaCl and DI water as feeds at 20 bar. Reproducible data obtained in the 2nd and 3rd runs confirm its stability under high hydraulic pressure differences. Comparing to other PRO membranes reported in the literature, the newly developed membrane exhibits not only the smallest slope between water flux decline and ΔPΔP increase but also the lowest ratio of reverse salt flux to water flux. Thus, the effective osmotic driving force could be well maintained even under high pressure operations. For the first time, the effect of feed pressure buildup induced by feed flowrate was evaluated towards PRO performance. A slight increment in feed pressure buildup was found to be beneficial to water flux and power density up to 10.06 W m−2 without comprising the reverse salt flux. We believe this study may open up new perspectives on outer-selective PRO hollow fiber membranes and provide useful insights to understand and design next-generation outer-selective TFC hollow fiber membranes for osmotic power generation.

  7. Effect of composition on optical properties of GeSe3–Sb2Se3–ZnSe thin films

    Indian Academy of Sciences (India)

    M R Balboul; H M Hosni; M A Soliman; S A Fayek

    2014-10-01

    Optical properties of the chalcogenides GeSe3, Sb2Se3, ZnSe, (GeSe3)80(Sb2Se3)20 and (GeSe3)70 (Sb2Se3)10(ZnSe)20 thin films are investigated. Incorporation of ZnSe into both GeSe3, Sb2Se3 results in amorphous (GeSe3)70(Sb2Se3)10(ZnSe)20 composition. The estimated optical energy gap, g, is found to decrease from 3.06 eV for ZnSe to 1.81 eV for (GeSe3)70(Sb2Se3)10(ZnSe)20. While, the band tail width, e, exhibits an opposite trend. The g behaviour is believed to be associated with cohesive energy, CE, as the incorporation of ZnSe lowers its value. The calculated number of the excess of Se–Se homopolar bonds is found to affect mainly the e values. The refractive index, , is discussed in terms of Wemple–DiDomenico single oscillator dispersion model in the normal dispersion region. The oscillator energy, o, and the dispersion energy, d, are determined for films under investigation.

  8. Effects of hydrophilic solvent and oxidation resistance post surface treatment on molecular structure and forward osmosis performance of polyamide thin-film composite (TFC) membranes

    Science.gov (United States)

    Jia, Qibo; Xu, Yangyu; Shen, Jianquan; Yang, Haijun; Zhou, Lu

    2015-11-01

    In this article, novel hydrophilic solvents and antioxidants were used to post-treat aromatic polyamide thin-film composite (TFC) hollow fiber forward osmosis (FO) membranes. The effects of trimesoyl chloride (TMC) and oxalic acid on the structure of polyamide skin layer were investigated using ATR-FTIR and XPS analyses. Pure water flux and rejection of salts were detected using 2 M NaCl solution as draw solutions in FO processes. The results demonstrated that hydrophilic solvent N-methyl pyrrolidone (NMP) enhanced the water flux and kept a high salt retention of the TFC FO membrane. TMC and oxalic acid were both found to improve the oxidation resistance properties of the skin layer of TFC membrane because the electron-withdrawing carboxyl groups reduced the activity of polyamide molecular. The effects of the oxalic acid and carbodiimide on the molecular structures and the FO water flux of the polyamide TFC membranes were more marked than those of TMC. The novel TFC FO membrane treated by oxalic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) exhibited a high level of water flux (20.33 L m-2 h-1), and the rates of salt rejection and salt reverse rejection were higher by 50% and 83%, respectively.

  9. Development of thin-film composite forward osmosis hollow fiber membranes using direct sulfonated polyphenylenesulfone (sPPSU) as membrane substrates.

    Science.gov (United States)

    Zhong, Peishan; Fu, Xiuzhu; Chung, Tai-Shung; Weber, Martin; Maletzko, Christian

    2013-07-02

    This study investigates a new approach to fabricate thin-film composite (TFC) hollow fiber membranes via interfacial polymerization for forward osmosis (FO) applications. Different degrees of sulfonation of polyphenylenesulfone (PPSU) were adopted as membrane substrates to investigate their impact on water flux. It has been established that the degree of sulfonation plays a role in both creating a macrovoid-free structure and inducing hydrophilicity to bring about higher water fluxes. The fabricated membranes exhibit extremely high water fluxes of 30.6 and 82.0 LMH against a pure water feed using 2.0 M NaCl as the draw solution tested under FO and pressure retarded osmosis (PRO) modes, respectively, while maintaining low salt reverse fluxes below 12.7 gMH. The structural parameter (S) displays remarkable decreases of up to 4.5 times as the membrane substrate is switched from a nonsulfonated to sulfonated one. In addition, the newly developed TFC-FO membranes containing 1.5 mol % sPPSU in the substrate achieves a water flux of 22 LMH in seawater desalination using a 3.5 wt % NaCl model solution and 2.0 M NaCl as the draw solution under the PRO mode. To the best of our knowledge, this value is the highest ever reported for seawater desalination using flat and hollow fiber FO membranes. The use of sulfonated materials in the FO process opens up a frontier for sustainable and efficient production of potable water.

  10. Hexagonal-to-cubic phase transformation in composite thin films induced by FePt nanoparticles located at PS/PEO interfaces.

    Science.gov (United States)

    Aissou, Karim; Fleury, Guillaume; Pecastaings, Gilles; Alnasser, Thomas; Mornet, Stéphane; Goglio, Graziella; Hadziioannou, Georges

    2011-12-06

    The organization process of asymmetric poly(styrene-block-ethylene oxide) (PS-b-PEO) copolymer thin films blended with FePt nanoparticles is studied. In a first step, it is shown that FePt nanoparticles stabilized by oleic acid ligands are distributed within the PS matrix phase, whereas the same particles partially covered with short dopamine-terminated-methoxy poly(ethylene oxide) (mPEO-Dopa) are located at PS/PEO interfaces. The swelling of PS domains, induced by FePt_oleic acid nanoparticles during the solvent annealing process, results in formation of a disordered microstructure in comparison to the well-organized hexagonally close-packed (HCP) cylinder phase formed in the neat PS-b-PEO copolymer. The evolution of the microstructure of PS-b-PEO/FePt_mPEO-Dopa composite has been investigated for different solvent annealing treatments. Under high-humidity conditions during the vapor annealing process, the addition of FePt nanoparticles results in formation of spheres in the film split into terraces. The upper and lower terraces are occupied by spheres organized in an unusual square and HCP phases, respectively. Under low-humidity conditions, undulated PEO cylinders oriented parallel to substrate are formed in the presence of FePt nanoparticles. In this case, we observe that most of the nanoparticles accumulate within the core of topological defects, which induces a low nanoparticle concentration at the PS/PEO interfaces and so stabilizes an intermediate undulated cylinder phase.

  11. Influence of plasma density on the chemical composition and structural properties of pulsed laser deposited TiAlN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Quiñones-Galván, J. G.; Camps, Enrique [Departamento de Física, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, México D.F. C.P. 11801 (Mexico); Muhl, S. [Instituto de Investigaciones en Materiales, UNAM, México D.F. C.P. 04510 (Mexico); Flores, M. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, Apdo. Postal 307, C.P. 45101 Zapopan, Jalisco (Mexico); Campos-González, E. [Departamento de Física, CINVESTAV-IPN, Apdo. Postal 14-740, México D.F. 07360 (Mexico)

    2014-05-15

    Incorporation of substitutional Al into the TiN lattice of the ternary alloy TiAlN results in a material with improved properties compared to TiN. In this work, TiAlN thin films were grown by the simultaneous ablation of Ti and Al targets in a nitrogen containing reactive atmosphere. The deposit was formed on silicon substrates at low deposition temperature (200 °C). The dependence of the Al content of the films was studied as a function of the ion density of the plasma produced by the laser ablation of the Al target. The plasma parameters were measured by means of a planar Langmuir probe and optical emission spectroscopy. The chemical composition of the films was measured by energy dispersive X-ray spectroscopy. The results showed a strong dependence of the amount of aluminum incorporated in the films with the plasma density. The structural characterization of the deposits was carried out by Raman spectroscopy, X-ray diffraction, and transmission electron microscopy, where the substitutional incorporation of the Al into the TiN was demonstrated.

  12. Sustainable Process for the Preparation of High-Performance Thin-Film Composite Membranes using Ionic Liquids as the Reaction Medium.

    Science.gov (United States)

    Mariën, Hanne; Bellings, Lotte; Hermans, Sanne; Vankelecom, Ivo F J

    2016-05-23

    A new form of interfacial polymerization to synthesize thin-film composite membranes realizes a more sustainable membrane preparation and improved nanofiltration performance. By introducing an ionic liquid (IL) as the organic reaction phase, the extremely different physicochemical properties to those of commonly used organic solvents influenced the top-layer formation in several beneficial ways. In addition to the elimination of hazardous solvents in the preparation, the m-phenylenediamine (MPD) concentration could be reduced 20-fold, and the use of surfactants and catalysts became redundant. Together with the more complete recycling of the organic phase in the water/IL system, these factors resulted in a 50 % decrease in the mass intensity of the top-layer formation. Moreover, a much thinner top layer with a high ethanol permeance of 0.61 L m(-2)  h(-1)  bar(-1) [99 % Rose Bengal (RB, 1017 Da) retention; 1 bar=0.1 MPa] was formed without the use of any additives. This EtOH permeance is 555 and 161 % higher than that for the conventional interfacial polymerization (without and with additives, respectively). In reverse osmosis, high NaCl retentions of 97 % could be obtained. Finally, the remarkable decrease in the membrane surface roughness indicates the potential for reduced fouling with this new type of membrane.

  13. Controlled Architecture of Dual-Functional Block Copolymer Brushes on Thin-Film Composite Membranes for Integrated "Defending" and "Attacking" Strategies against Biofouling.

    Science.gov (United States)

    Ye, Gang; Lee, Jongho; Perreault, François; Elimelech, Menachem

    2015-10-21

    We report a new macromolecular architecture of dual functional block copolymer brushes on commercial thin-film composite (TFC) membranes for integrated "defending" and "attacking" strategies against biofouling. Mussel-inspired catechol chemistry is used for a convenient immobilization of initiator molecules to the membrane surface with the aid of polydopamine (PDA). Zwitterionic polymer brushes with strong hydration capacity and quaternary ammonium salt (QAS) polymer brushes with bactericidal ability are sequentially grafted on TFC membranes via activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP), an environmentally benign and controlled polymerization method. Measurement of membrane intrinsic transport properties in reverse osmosis experiments shows that the modified TFC membrane maintains the same water permeability and salt selectivity as the pristine TFC membrane. Chemical force microscopy and protein/bacterial adhesion studies are carried out for a comprehensive evaluation of the biofouling resistance and antimicrobial ability, demonstrating low biofouling propensity and excellent bacterial inactivation for the modified TFC membrane. We conclude that this polymer architecture, with complementary "defending" and "attacking" capabilities, can effectively prevent the attachment of biofoulants and formation of biofilms and thereby significantly mitigate biofouling on TFC membranes.

  14. Effect of CO{sub 2}-laser irradiation on properties and performance of thin-film composite polyamide reverse osmosis membrane

    Energy Technology Data Exchange (ETDEWEB)

    Jahangiri, Foad; Mousavi, Seyyed Abbas; Farhadi, Fathollah; Sabzi, Behnam; Chenari, Zeinab [Sharif University of Technology, Tehran (Iran, Islamic Republic of); Vatanpour, Vahid [Kharazmi (Tarbiat Moallem) University, Tehran (Iran, Islamic Republic of)

    2016-03-15

    CO{sub 2}-laser irradiation was used to modify the surface properties of thin-film composite (TFC) polyamide reverse osmosis (RO) membranes. These membranes were first synthesized via interfacial polymerization of m-phenylenediamine (MPD) monomers and trimesoyl chloride (TMC) over porous polysulfone ultrafiltration support, followed by a CO{sub 2}-irradiation. AFM, ATR-FTIR, SEM and contact angle measurements were used to characterize the surface properties of these membranes. The ATR-FTIR results indicated that CO{sub 2}-laser irradiation did not induce any functional groups on the membrane surface. However, it was found that the laser irradiation enhanced the NaCl salt rejection and slightly reduced the permeate flux. Moreover, the maintenance of the flux in modified membranes was much higher than untreated ones. Specially, after 180 min of filtration, the reduction in initial flux for the unmodified membranes was 22%. However, the reduction in initial flux for the modified membranes was less than 5%. Bovine serum albumin (BSA) filtration revealed an improvement in the antifouling properties of the modified membranes. The changes in the membrane surface morphology showed that the roughness of membrane surface is reduced significantly.

  15. Surface structures and compositions of Au-Rh bimetallic nanoclusters supported on thin-film Al2O3/NiAl(100) probed with CO

    Science.gov (United States)

    Lee, Hsuan; Liao, Zhen-He; Hsu, Po-Wei; Hung, Ting-Chieh; Wu, Yu-Cheng; Lin, Yuwei; Wang, Jeng-Han; Luo, Meng-Fan

    2017-07-01

    The surface structures and compositions of Au-Rh bimetallic nanoclusters on an ordered thin film of Al2O3/NiAl(100) were investigated, primarily with infrared reflection absorption spectra and temperature-programmed desorption of CO as a probe molecule under ultrahigh-vacuum conditions and calculations based on density-functional theory. The bimetallic clusters were formed by sequential deposition of vapors of Au and Rh onto Al2O3/NiAl(100) at 300 K. Alloying in the clusters was active and proceeded toward a specific structure—a fcc phase, (100) orientation, and Rh core-Au shell structure, regardless of the order of metal deposition. For Au clusters incorporating deposited Rh, the Au atoms remained at the cluster surface through position exchange and became less coordinated; for deposition in reverse order, deposited Au simply decorated the surfaces of Rh clusters. Both adsorption energy and infrared absorption intensity were enhanced for CO on Au sites of the bimetallic clusters; both of them are associated with the bonding to Rh and also a decreased coordination number of CO-binding Au. These enhancements can thus serve as a fingerprint for alloying and atomic inter-diffusion in similar bimetallic systems.

  16. Structural, compositional and photoluminescence characteristics of CuInSe{sub 2} thin films prepared by close-spaced vapor transport

    Energy Technology Data Exchange (ETDEWEB)

    Zouaoui, A.; Chaffa, A.; Kesri, N. [U.S.T.H.B., Alger (Algeria). Inst. de Phys.; Lachab, M.; Hidalgo, M.L.; Llinares, C. [Montpellier-2 Univ. 34 (France). Centre d`Electronique et de Micro-Optoelectronique

    1999-02-08

    The present work deals with the investigation of the growth temperature effects on the properties of polycrystalline Cu-In-Se thin films, prepared by the close-spaced vapor technique (CSVT) using iodine as a transport agent. The deposition was performed onto glass substrates heated at temperatures ranging from 300 to 550 C. Characterizations by means of compositional analysis. X-ray diffraction, scanning electron microscopy, spectrophotometry and photoluminescence (PL) measurements were carried out. Cu-rich, near stoichiometric and In-rich layers with varying morphology and thickness (up to 10 {mu}m) were obtained. They were homogeneous and well-adherent to the substrate. Results also show that the physical properties are strongly dependent on the Cu/In ratio. Following vacuum annealing, the iodine generally present in the as-deposited Cu-rich samples disappeared while only the layers heat treated under a selenium atmosphere exhibit PL signals. These signals were used to locate, then to identify the energy levels associated with various intrinsic defects responsible for the electrical and optical properties. (orig.) 43 refs.

  17. Interfacial Chemical Composition and Molecular Order in Organic Photovoltaic Blend Thin Films Probed by Surface-Enhanced Raman Spectroscopy.

    Science.gov (United States)

    Razzell-Hollis, Joseph; Thiburce, Quentin; Tsoi, Wing C; Kim, Ji-Seon

    2016-11-16

    Organic electronic devices invariably involve transfer of charge carriers between the organic layer and at least one metal electrode, and they are sensitive to the local properties of the organic film at those interfaces. Here, we demonstrate a new approach for using an advanced technique called surface-enhanced raman spectroscopy (SERS) to quantitatively probe interfacial properties relevant to charge injection/extraction. Exploiting the evanescent electric field generated by a ∼7 nm thick layer of evaporated silver, Raman scattering from nearby molecules is enhanced by factors of 10-1000× and limited by a distance dependence with a measured decay length of only 7.6 nm. When applied to the study of an all-polymer 1:1 blend of P3HT and F8TBT used in organic solar cells, we find that the as-cast film is morphologically suited to charge extraction in inverted devices, with a top (anode) interface very rich in hole-transporting P3HT (74.5%) and a bottom (cathode) interface slightly rich in electron-transporting F8TBT (55%). While conventional, uninverted P3HT:F8TBT devices are reported to perform poorly compared to inverted devices, their efficiency can be improved by thermal annealing but only after evaporation of a metallic top electrode. This is explained by changes in composition at the top interface: annealing prior to silver evaporation leads to a greater P3HT concentration at the top interface to 83.3%, exaggerating the original distribution that favored inverted devices, while postevaporation annealing increases the concentration of F8TBT at the top interface to 34.8%, aiding the extraction of electrons in a conventional device. By nondestructively probing buried interfaces, SERS is a powerful tool for understanding the performance of organic electronic devices.

  18. Importance of the support material in thin palladium composite membranes for steady hydrogen permeation at elevated temperatures.

    Science.gov (United States)

    Okazaki, Junya; Ikeda, Takuji; Pacheco Tanaka, David A; Llosa Tanco, Margot A; Wakui, Yoshito; Sato, Koich; Mizukami, Fujio; Suzuki, Toshishige M

    2009-10-14

    Hydrogen permeation performance of palladium membranes supported on porous alpha-alumina and yttria-stabilized zirconia (YSZ) was studied at 300-850 degrees C. The hydrogen permeation flux across the palladium-alpha-alumina membrane decreased markedly during permeation tests conducted at >600 degrees C. The SEM and XPS studies of the post-test membrane revealed the presence of aluminium in the palladium layer. Such migration of aluminium was not observed by heating the palladium-alpha-alumina membrane under an argon atmosphere, indicating that hydrogen is responsible for this phenomenon. Hydrogen-induced strong metal-support interaction might be related to this considerable loss of the hydrogen flux. Reduction of alumina to Al(0) by active hydrogen at the membrane-support interface and subsequent migration of Al(0) into the palladium layer represents the most plausible mechanism for the aluminium diffusion. Actually, Al(0) that migrated into the palladium membrane layer generated less hydrogen-permeable palladium-aluminium alloy or inter-metallic compound phase. In contrast, no such strong interaction was found between the YSZ support and the palladium membrane. This composite membrane exhibited a steady permeation of hydrogen at 650 degrees C for 336 h. Having a remarkably high reduction potential, Y(III) is unlikely to be reduced to Y(0), although Zr(IV) has a comparable reduction potential to that of Al(III). A binary phase diagram shows a liquid alloy phase present for the Pd/Al couple at temperatures greater than 615 degrees C (eutectic point), while an inter-metallic compound or liquid alloy phase in the Pd-Zr binary system is not apparent at temperatures less than 750 degrees C. Consequently, inter-diffusion of zirconium with palladium did not occur during operations at 650 degrees C.

  19. Influence of air exposure on the compositional nature of Zn{sub 3}N{sub 2} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, C. Garcia, E-mail: carlos.garcia@uam.es; Pau, J.L.; Hernandez, M.J.; Cervera, M.; Ruiz, E.; Piqueras, J.

    2012-11-01

    Zinc nitride (Zn{sub 3}N{sub 2}) films were prepared by radio-frequency magnetron sputtering from a pure Zn target in a N{sub 2} ambient. Films were deposited on glass and Si(100) substrates at 298- and 473-K substrate temperatures (T{sub s}). Ion beam analysis (IBA) techniques, spectroscopic ellipsometry (SE) and transmission spectroscopy were used to characterize the samples as a function of T{sub s} and time. IBA studies showed that the Zn and N concentrations matched the stoichiometric values 3:2 of the cubic anti-bixbyte structure and revealed the partial transformation of Zn{sub 3}N{sub 2} into zinc oxide (ZnO) due to the exposure to ambient air. IBA and SE techniques revealed films grown at higher T{sub s} were less affected by the oxidation process. Transmission spectroscopy showed that the band gap energy blue shifted as T{sub s} decreased. It was also found that the oxidation process produced a blue shift of the band gap energy. For the sake of comparison, ZnO/Zn{sub 3}N{sub 2} heterostructures were synthesized using the same system and characterized in parallel to unintentionally oxidized nitride layers. SE studies of the heterostructure showed that the deposition of a ZnO layer helped to prevent nitride oxidation. - Highlights: Black-Right-Pointing-Pointer Zinc nitride (Zn{sub 3}N{sub 2}) films were grown by rf-magnetron sputtering at 298- and 473-K. Black-Right-Pointing-Pointer Compositional and optical properties were studied vs. growth temperature and time. Black-Right-Pointing-Pointer Those studies revealed films grown at higher temperatures were less oxidized. Black-Right-Pointing-Pointer Transmission results showed energy gap blue shifted as growth temperature decreased. Black-Right-Pointing-Pointer Zinc oxide layer atop Zn{sub 3}N{sub 2} helped to prevent the oxidation process.

  20. Composites

    Science.gov (United States)

    Taylor, John G.

    The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

  1. Composites

    Science.gov (United States)

    Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-Nędza, A.; Mackiewicz, S.; Dutkiewicz, J.

    2014-11-01

    It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

  2. Investigation of the influence of surface composition on the charge state distribution of ∼keV hydrogen exiting thin carbon foils for space plasma instrumentation

    Science.gov (United States)

    Allegrini, Frédéric; Coulter, Kent; Ebert, Robert W.; Nicolaou, Georgios; Poenitzsch, Vasiliki Zorbas

    2016-06-01

    Energetic neutral atom (ENA) imaging techniques have become a powerful tool for remotely probing plasma environments in space. ENA imagers cover energies from 0.01 keV up to a few MeV, and they use different techniques to cover such a broad energy range. Most of them convert the ENA into a charged particle to remove the converted ENA from the initial neutral direction. In the >∼0.2 keV/nuc to 10's of keV/nuc range, the conversion subsystem is usually an ultra-thin carbon foil. The sensitivity of ENA imagers based on charge conversion by carbon foils is driven by the ability of these foils to convert a neutral atom into an ion. The charge state distribution after the carbon foils is a strong function of the chemical and physical properties of the exit surface. In this study, we analyze the composition and structure of the surface using X-ray photoelectron spectroscopy. The surface is roughly 88% carbon and 12% oxygen, forming strong Csbnd O bonds. Annealing the foil lowers the oxygen content to about 9%. We coat the surface of the foils with Au, Al2O3, or MgO. We compare the exit charge state distributions of hydrogen prior to and post coatings. While no significant difference is observed in the exit charge state for the Au and Al2O3 coatings, there is a slight decrease of the positive fraction after MgO. The annealing of the foil has the benefit of reducing the angular scattering of hydrogen by a factor of ∼1.2. This is a significant improvement that has the potential to increase sensitivity of ENA imagers.

  3. Effects of hydrophilic solvent and oxidation resistance post surface treatment on molecular structure and forward osmosis performance of polyamide thin-film composite (TFC) membranes

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Qibo; Xu, Yangyu [School of Environment, Tsinghua University, Beijing 100084 (China); Shen, Jianquan [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Yang, Haijun, E-mail: yanghj@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Zhou, Lu, E-mail: zhoulu@tsinghua.edu.cn [School of Environment, Tsinghua University, Beijing 100084 (China)

    2015-11-30

    Graphical abstract: - Highlights: • NMP promotes swelling of polyamide, which enhances the TFC FO membrane water flux. • Electron-withdrawing carboxyl groups reduce the activity of polyamide molecules. • TMC and oxalic acid can improve the oxidation resistance properties of the FO membrane. • Oxalic acid and EDC improve the FO membrane separation performance significantly. - Abstract: In this article, novel hydrophilic solvents and antioxidants were used to post-treat aromatic polyamide thin-film composite (TFC) hollow fiber forward osmosis (FO) membranes. The effects of trimesoyl chloride (TMC) and oxalic acid on the structure of polyamide skin layer were investigated using ATR-FTIR and XPS analyses. Pure water flux and rejection of salts were detected using 2 M NaCl solution as draw solutions in FO processes. The results demonstrated that hydrophilic solvent N-methyl pyrrolidone (NMP) enhanced the water flux and kept a high salt retention of the TFC FO membrane. TMC and oxalic acid were both found to improve the oxidation resistance properties of the skin layer of TFC membrane because the electron-withdrawing carboxyl groups reduced the activity of polyamide molecular. The effects of the oxalic acid and carbodiimide on the molecular structures and the FO water flux of the polyamide TFC membranes were more marked than those of TMC. The novel TFC FO membrane treated by oxalic acid and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC) exhibited a high level of water flux (20.33 L m{sup −2} h{sup −1}), and the rates of salt rejection and salt reverse rejection were higher by 50% and 83%, respectively.

  4. A study on composition, structure and optical properties of copper-poor CIGS thin film deposited by sequential sputtering of CuGa/In and In/(CuGa+In) precursors

    Science.gov (United States)

    Park, Seong-Un; Sharma, Rahul; Ashok, K.; Kang, San; Sim, Jae-Kwan; Lee, Cheul-Ro

    2012-11-01

    Copper-poor CIGS thin films were fabricated by using two precursor of CuGa/In and In/(CuGa+In) onto the Mo coated soda-lime glass (SLG) by the sequential sputtering of CuGa and In targets. The CIG precursors were converted into CIGS absorption thin film by selenization process. The X-ray diffraction (XRD) patterns of CIGS absorber from CuGa/In precursor exhibits strong (112) preferred orientation that is more stable than (220)/(204) as compared to In/(CuGa+In) precursor. The elemental composition uniformity onto the surface and along depth were extensively analyzed with energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). For as-fabricated CIGS thin films from In/(CuGa+In) and CuGa/In precursors, the atomic (at%) composition values of [Cu]//[In+Ga]/=1.14, 1.08 and [Ga]/[In+Ga]=0.33, 0.20 were observed, respectively that is well matched for highest efficient CIGS-based solar cell so far. SIMS confirmed that the Ga profile is not through the depth of CIGS thin film attributed a consistent band gap of 1.04 and 1.08 eV. Further, PL spectrum of CIGS absorber formed by CuGa/In precursor exhibits relatively narrow emission peak as compared to In/(CuGa+In) precursor. It is attributed to decrease defect density with uniform composition in the CIGS absorber. The carrier concentration (Np) found to increase from 1020 to 1021 cm-3 orders with the increase of Cu/(In+Ga) at.% from 0.93 to 1.02, which is related to the increasing carrier concentration for stoichiometric CIGS films.

  5. The study of structural properties of carbon nanotubes decorated with NiFe{sub 2}O{sub 4} nanoparticles and application of nano-composite thin film as H{sub 2}S gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Hajihashemi, R., E-mail: Rezvan.hajihashemi@yahoo.com [Department of Physics, Payame Noor University, Mashhad (Iran, Islamic Republic of); Rashidi, Ali M.; Alaie, M. [Nanotechnology Research Center, Research Institute of Petroleum Industry, P.O., Tehran (Iran, Islamic Republic of); Mohammadzadeh, R. [Department of Physics, Shahreza Branch, Islamic Azad University, Shahreza (Iran, Islamic Republic of); Izadi, N. [Nanotechnology Research Center, Research Institute of Petroleum Industry, P.O., Tehran (Iran, Islamic Republic of)

    2014-11-01

    Nano-composite of multiwall carbon nanotube, decorated with NiFe{sub 2}O{sub 4} nanoparticles (NiFe{sub 2}O{sub 4}–MWCNT), was synthesized using the sol–gel method. NiFe{sub 2}O{sub 4}–MWCNTs were characterized using different methods such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM) and vibrating sample magnetometer (VSM). The average size of the crystallites is 23.93 nm. The values of the saturation magnetization (M{sub S}), coercivity (H{sub C}) and retentivity (M{sub R}) of NiFe{sub 2}O{sub 4}–MWCNTs are obtained as 15 emu g{sup −1}, 21 Oe and 5 emu g{sup −1}, respectively. In this research, NiFe{sub 2}O{sub 4}–MWCNT thin films were prepared with the spin-coating method. These thin films were used as the H{sub 2}S gas sensor. The results suggest the possibility of the utilization of NiFe{sub 2}O{sub 4}–MWCNT nano-composite, as the H{sub 2}S detector. The sensor shows appropriate response towards 100 ppm of H{sub 2}S at 300 °C. - Highlights: • Nano-composite the average size of the crystallites is 23.93 nm. • NiFe{sub 2}O{sub 4} thin films were prepared with spin-coating method. • These thin films were used as the H{sub 2}s gas sensor. • The sensor shows appropriate response towards 100 ppm of H{sub 2}S at 300 °C.

  6. Influence of gold species (AuCl4(-) and AuCl2(-)) on self-assembly of PS-b-P2VP in solutions and morphology of composite thin films fabricated at the air/liquid interfaces.

    Science.gov (United States)

    Zhao, Xingjuan; Wang, Qian; Zhang, Xiaokai; Lee, Yong-Ill; Liu, Hong-Guo

    2016-01-21

    Composite thin films doped with Au species were fabricated at an air/liquid interface via a series of steps, including the mass transfer of polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) across the liquid/liquid interface between a DMF/CHCl3 solution and an aqueous solution containing either AuCl4(-) or AuCl2(-), self-assembly of PS-b-P2VP in a mixed DMF-water solution, and adsorption and further self-organization of the formed aggregates at the air/liquid interface. This is a new approach for fabricating composite polymer films and can be completed within a very short time. AuCl4(-) and AuCl2(-) ions were found to significantly influence the self-assembly behavior of the block copolymer and the morphologies of the composite films, leading to the formation of nanowire arrays and a foam structure at the air/liquid interface, respectively, which originated from rod-like micelles and microcapsules that had formed in the respective solutions. The effect of the metal complex was analyzed based on the packing parameters of the amphiphilic polymer molecules in different microenvironments and the interactions between the pyridine groups and the metal chloride anions. In addition, these composite thin films exhibited stable and durable performance as heterogeneous catalysts for the hydrogenation of nitroaromatics in aqueous solutions.

  7. Damping properties of epoxy-based composite embedded with sol–gel-derived Pb(Zr0.53Ti0.47)O3 thin film with different thicknesses

    Indian Academy of Sciences (India)

    Guo Dongyun; Mao Wei; Qin Yan; Huang Zhixiong; Wang Chuanbin; Shen Qiang; Zhang Lianmeng

    2012-06-01

    Pb(Zr0.53Ti0.47)O3 (PZT) thin films were prepared on Pt/Ti/SiO2/Si substrate by sol–gel method. The effect of film thickness on microstructure, ferroelectric and dielectric properties was investigated. The single-phase PZT films were obtained with different thicknesses. PZT films with a thickness of 190–440 nm had better dielectric and ferroelectric properties. The epoxy/PZT film/epoxy sandwiched composites were prepared. The thickness of PZT films influenced their damping properties of the composites, and the epoxy-based composites embedded with 310 nm-thick PZT films had the largest damping loss factor of 0.915.

  8. Environmentally stable flexible metal-insulator-metal capacitors using zirconium-silicate and hafnium-silicate thin film composite materials as gate dielectrics.

    Science.gov (United States)

    Meena, Jagan Singh; Chu, Min-Ching; Wu, Chung-Shu; Ravipati, Srikanth; Ko, Fu-Hsiang

    2011-08-01

    Fully flexible metal-insulator-metal (MIM) capacitors fabricated on 25 microm thin polyimide (PI) substrates via the surface sol-gel process using 10-nm-thick zirconium-silicate (ZrSixOy) and hafnium-silicate (HfSimOn) films as gate dielectrics. The surface morphology of the ZrSixOy and HfSimOn films were investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free surface growth had occurred on the PI. Both the films treated with oxygen (O2) plasma and annealing (ca. 250 degrees C) consisted of amorphous phase; confirmed by X-ray diffraction. We employed X-ray photoelectron spectroscopy (XPS) at high resolution to examine the chemical composition of the films subjected to various treatment conditions. The shift of the XPS peaks towards higher binding energy revealed the O2 plasma-pretreatment followed by annealing was the most effective process to the surface oxidation at relatively low-temperature, for further passivate the grease traps and making dielectric films thermally stable. The ZrSixOy and HfSimOn films in sandwich-like MIM configuration on the PI substrates exhibited the low leakage current densities of 7.1 x 10(-9) and 8.4 x 10(-9) A/cm2 at applied electric field of 10 MV/cm and maximum capacitance densities of 7.5 and 5.3 fF/microm2 at 1 MHz, respectively. In addition, the ZrSixOy and HfSimOn films in MIM capacitors showed the estimated dielectric constants of 8.2 and 6.0, respectively. Prior to use of flexible MIM capacitors in advanced flexible electronic devices; the reliability test was studied by applying day-dependent leakage current density measurements up to 30 days. These films of silicate-surfactant mesostructured materials have special interest to be used as gate dielectrics in future for flexible metal-oxide-semiconductor devices.

  9. 人工复合铁电多层膜热释电性质的理论研究%Theoretical Investigation on Pyroelectric Properties of Artificial Composite Ferroelectric Thin Films

    Institute of Scientific and Technical Information of China (English)

    陈辉; 成泰民; 陈思群

    2011-01-01

    A theoretical model of ferroelectric thin film composite by three ferroelectric materials with different phase-transition temperatures has been built, in which the three components composite perpendicular to the polarization. Using ginzburg-landau-devonshire(GLD) theory, a local distribution function has been introduced to describe the properties of the transition layers, and the pyroelectric properties of the composite ferroelectric thin films have been mainly investigated. Polarization distributions, transition temperatures and pyroelectric coefficients were calculated with different composite methods. It was shown that the composite methods had importance influence on polarization and pyroelectric properties; two pyroelectric peaks appeared with the change of the film temperature. The composite ferroelectric thin film under new model presented many new properties, especially provide a reference on the improvement of pyroelectric devices. This composite film may be a new choice of multi-layer films in applications.%建立3种具有不同相变温度的铁电材料垂直于极化方向复合而成的铁电薄膜的理论模型,在ginzburg-landau-devonshire (GLD)唯象理论的框架下展开研究,同时引入局域分布函数来描述不同材料间过渡层的性质,主要研究了复合铁电薄膜的热释电性质.通过改变3种不同铁电材料的复合方式,计算了铁电多层膜内部的极化强度分布、相变温度及热释电系数.研究表明,具有不同相变温度的铁电材料间的复合方式对铁电薄膜的极化和热释电性质有着重要的影响,3种不同材料复合而成的铁电薄膜随着温度的变化出现了2个热释电峰.新模型下的复合铁电薄膜表现很多新的特性,尤其对于铁电热释电器件性能的改良提出了一种参考,该种复合薄膜也许能够成为通常使用的多层膜的一种选择.

  10. Biomimetic thin film deposition

    Science.gov (United States)

    Rieke, P. C.; Campbell, A. A.; Tarasevich, B. J.; Fryxell, G. E.; Bentjen, S. B.

    1991-04-01

    Surfaces derivatized with organic functional groups were used to promote the deposition of thin films of inorganic minerals. These derivatized surfaces were designed to mimic the nucleation proteins that control mineral deposition during formation of bone, shell, and other hard tissues in living organisms. By the use of derivatized substrates control was obtained over the phase of mineral deposited, the orientation of the crystal lattice and the location of deposition. These features are of considerable importance in many technically important thin films, coatings, and composite materials. Methods of derivatizing surfaces are considered and examples of controlled mineral deposition are presented.

  11. Interfacially synthesized thin-film composite reverse osmosis membranes and their surface modification%界面聚合反渗透复合膜材料及其表面修饰

    Institute of Scientific and Technical Information of China (English)

    俞三传

    2011-01-01

    Thin-film composite reverse osmosis membranes were developed by interfacial polymerization of metaphenylenediamine and polyacyl chlorides such as 5-chloroformyloxy-isophthaloyl chloride (CFIC)? 5-isocyanato-isophthaloyl chloride (ICIC), and 1,3, 5-cyclohexanetriacyl chloride (CHTC). The properties of the resulting membranes were studied in terms of surface chemical structure, surface charge, pure water permeability, and salt rejection rate as well. Surface modification of the thin-film composite polyamide reverse osmosis membrane was also studied for improved membrane properties. It was found that the properties and separation performance of the thin-film composite reverse osmosis could be modulated and optimized by varying the monomers used in reaction, membrane preparation conditions, as well as surface modification.%针对我国反渗透复合膜材料研究领域存在的膜材料品种单一、膜性能相对较差、膜产品缺乏核心竞争力等现状,重点开展了界面聚合反渗透复合膜材料及其表面修饰方面的研究工作.从功能单体与制备工艺入手,研究开发高性能反渗透复合膜材料;采用表面改性技术,对界面聚合反渗透复合膜材料进行表面功能化修饰,研究开发界面聚合反渗透复合膜材料的表面改性实用技术;以期为我国反渗透复合膜材料及其产业的发展提供核心材料和先进制备技术.

  12. Composite thin film materials on the basis of silver nanostructures on polymer matrix by methods of chemical metallization and self-assembling

    Science.gov (United States)

    Skoptsov, Evgeniy; Agabekov, Vladimir; Binhussain, Mohammed A.; Egorov, Dmitriy; Ropot, Piotr

    2014-08-01

    The techniques of formation of thin metallic coatings by deposition of silver nanoparticles (NPs) from solution onto the surface of glass and silicon substrates modified by polyelectrolytes were developed. The possibilities of the adsorption of individual silver particles, as well as creation of continuous films on their basis, were shown. The transmission, absorption and reflection spectra of obtained coatings were investigated. The most promising structure for metamaterials creation from the list of formed one was determined—solid thin film of Ag NPs on a glass substrate modified by polyethylenimine.

  13. Free vibration of a rotating composite thin-walled beam with large deformation%旋转几何非线性复合材料薄壁梁的自由振动分析

    Institute of Scientific and Technical Information of China (English)

    任勇生; 代其义; 孙丙磊; 张纯金

    2013-01-01

    A rotating composite thin-walled beam is a class of typical structure used in study on vibration control of advanced helicopter blades and wind turbine blades.The dynamic behavior investigation of this structure is of significance in theory and practice.However,so far the dynamic behavior study on the above-mentioned structure is limited only for rotating composite beams with small elastic deformation.The free vibration of a rotating composite thin-walled beam with large deformation was studied here.The governing nonlinear equations of motion for the rotating composite thin-walled beam were derived using Hamilton's energy principle and the variational-asymptotical method (VAM) on the basis of von Karman's assumption.The nonlinear free vibration of the beam was studied using Galerkin method and the harmonic balance method.The large amplitude of free vibration of the beam could be expressed as a nonlinear eigenvalue problem and solved using an iterative solution procedure.Numerical results were obtained for a laminated composite configuration thin-walled beam with circumferentially uniform stiffness (CUS).The results showed the effect of fiber orientation and rotating speed on the relation between nonlinear natural frequency and amplitude.The developed model could be capable of describing nonlinear free vibration behaviors of a rotating composite thin-walled beam with large deformation.%研究具有几何非线性的旋转复合材料薄壁梁的自由振动.梁的变形引入了Von Kármán几何非线性,基于Hamilton原理和变分渐进法(Variational-Asymptotical Method-VMA),导出旋转复合材料薄壁梁的非线性振动偏微分方程组.采用Galerkin法将振动方程离散化为常微分方程组.借助于谐波平衡法(Harmonic Balance Method-HBM)建立自由振动的振幅-非线性固有频率关系方程.将上述方程化为非线性特征值问题,采用迭代算法进行求解.将所建立的旋转复合材料薄壁梁非线性自由振动分

  14. Multilayer thin films with compositional PbZr0.52Ti0.48O3/Bi1.5Zn1.0Nb1.5O7 layers for tunable applications.

    Science.gov (United States)

    Yu, Shihui; Li, Lingxia; Zhang, Weifeng; Sun, Zheng; Dong, Helei

    2015-05-11

    The dielectric properties and tunability of multilayer thin films with compositional PbZr0.52Ti0.48O3/Bi1.5Zn1.0Nb1.5O7 (PZT/BZN) layers (PPBLs) fabricated by pulsed laser deposition on Pt/TiO2/SiO2/Si substrate have been investigated. Dielectric measurements indicate that the PZT/BZN bilayer thin films exhibit medium dielectric constant of about 490, low loss tangent of 0.017, and superior tunable dielectric properties (tunability=49.7% at 500 kV/cm) at a PZT/BZN thickness ratio of 3, while the largest figure of merit is obtained as 51.8. The thickness effect is discussed with a series connection model of bilayer capacitors, and the calculated dielectric constant and loss tangent are obtained. Furthermore, five kinds of thin-film samples comprising single bilayers, two, three, four and five PPBLs were also elaborated with the final same thickness. The four PPBLs show the largest dielectric constant of ~538 and tunability of 53.3% at a maximum applied bias field of 500 kV/cm and the lowest loss tangent of ~0.015, while the largest figure of merit is 65.6. The results indicate that four PPBLs are excellent candidates for applications of tunable devices.

  15. Research of electrosurgical unit with novel antiadhesion composite thin film for tumor ablation: Microstructural characteristics, thermal conduction properties, and biological behaviors.

    Science.gov (United States)

    Shen, Yun-Dun; Lin, Li-Hsiang; Chiang, Hsi-Jen; Ou, Keng-Liang; Cheng, Han-Yi

    2016-01-01

    The objective of this study was to use surface functionalization to evaluate the antiadhesion property and thermal injury effects on the liver when using a novel electrosurgical unit with nanostructured-doped diamond-like carbon (DLC-Cu) thin films for tumor ablations. The physical and chemical properties of DLC-Cu thin films were characterized by contact angle goniometer, scanning electron microscope, and transmission electron microscope. Three-dimensional (3D) hepatic models were reconstructed using magnetic resonance imaging to simulate a clinical electrosurgical operation. The results indicated a significant increase of the contact angle on the nanostructured DLC-Cu thin films, and the antiadhesion properties were also observed in an animal model. Furthermore, the surgical temperature in the DLC-Cu electrosurgical unit was found to be significantly lower than the untreated unit when analyzed using 3D models and thermal images. In addition, DLC-Cu electrodes caused a relatively small injury area and lateral thermal effect. The results indicated that the nanostructured DLC-Cu thin film coating reduced excessive thermal injury and tissue adherence effect in the liver.

  16. Nonlinearities in composition dependence of structure parameters and magnetic properties of nanocrystalline fcc/bcc-mixed Co-Ni-Fe thin films

    NARCIS (Netherlands)

    Chechenin, N. G.; Khomenko, E. V.; Vainchtein, D. I.; De Hosson, J. Th. M.

    2008-01-01

    In this report, the nonlinearities are analyzed in fcc-to-bcc (fcc/bcc) population ratio, lattice parameters (a(exp)(fcc)/a(ideal)(fcc) and a(exp)(bcc)/a(ideal)(bcc)) and saturation magnetization (I(S)(obs)/I(S)(a)) of the electrodeposited thin Co-Fe-Ni films as a function of average number of elect

  17. Applicability of X-ray fluorescence spectroscopy as method to determine thickness and composition of stacks of metal thin films: A comparison with imaging and profilometry

    NARCIS (Netherlands)

    Vrielink, J.A.M.; Tiggelaar, R.M.; Gardeniers, J.G.E.; Lefferts, L.

    2012-01-01

    In this work the applicability of X-ray fluorescence spectroscopy (XRF) for fast, accurate and non-destructive determination of the thickness of a variety of single-layer and multi-layer metal thin films deposited on glass and silicon is investigated. Data obtained with XRF is compared with informat

  18. The study of structural properties of carbon nanotubes decorated with NiFe₂O₄ nanoparticles and application of nano-composite thin film as H₂S gas sensor.

    Science.gov (United States)

    Hajihashemi, R; Rashidi, Ali M; Alaie, M; Mohammadzadeh, R; Izadi, N

    2014-11-01

    Nano-composite of multiwall carbon nanotube, decorated with NiFe2O4 nanoparticles (NiFe2O4-MWCNT), was synthesized using the sol-gel method. NiFe2O4-MWCNTs were characterized using different methods such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM) and vibrating sample magnetometer (VSM). The average size of the crystallites is 23.93 nm. The values of the saturation magnetization (MS), coercivity (HC) and retentivity (MR) of NiFe2O4-MWCNTs are obtained as 15 emu g(-1), 21Oe and 5 emu g(-1), respectively. In this research, NiFe2O4-MWCNT thin films were prepared with the spin-coating method. These thin films were used as the H2S gas sensor. The results suggest the possibility of the utilization of NiFe2O4-MWCNT nano-composite, as the H2S detector. The sensor shows appropriate response towards 100 ppm of H2S at 300°C. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Preparation and Characterization of Super-Hydrophilic TiO2/SiO2 Composite Thin Films%超亲水TiO2/SiO2复合薄膜的制备与表征

    Institute of Scientific and Technical Information of China (English)

    余家国; 赵修建; 林立; 韩建军; 赵青南

    2001-01-01

    通过sol-gel工艺在普通钠钙玻璃表面制备了均匀透明的TiO2/SiO2复合薄膜。实验结果表明:在TiO2薄膜中添加SiO2,可以抑制薄膜中TiO2晶粒的长大,同时薄膜表面的羟基含量增加,水在复合薄膜表面的润湿角下降,亲水能力增强。当SiO2含量为10~20 mol%时获得了润湿角为0℃的超亲水性薄膜。%The uniform transparent TiO2/SiO2 composite thin films were prepared via sol-gel processing on the soda lime glass substrates. The addition of SiOn. to TiO2 thin films can suppress the grain growth of TiO2 crystal in the TiO2 thin films, increase the hydroxyl content of TiO2 film, low the contact angle for water of TiO2 films and enhance the hydrophilic property of TiO2 films. The super-hydrophilic TiO2/SiO2 composite films with the contact angle of 0° were obtained by the addition of 10mol%~20mol% SiO2.

  20. Interrelatedness of Fe composition on structural and magnetic properties in Fe-doped SrRuO{sub 3} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Y.Z.; Chmaissem, O.; Kolesnik, S.; Brown, D.E.; Dabrowski, B.; Kimball, C.W. [Northern Illinois University, Institute for NanoScience, Engineering and Technology (INSET), Physics Department, DeKalb, IL (United States); Kim, T.W. [Korea Institute of Industrial Technology, Applied Optics and Energy Research Group, Gwangju (Korea, Republic of); Kim, M.S. [TongMyong University, Department of Information and Communication Engineering, Busan (Korea, Republic of); Genis, A.P. [Northern Illinois University, Institute for NanoScience, Engineering and Technology (INSET), Electrical Engineering Department, DeKalb, IL (United States); Song, J.H. [PaiChai University, Department of Information and Electronic Materials Engineering, Daejeon (Korea, Republic of)

    2014-06-15

    Fe-doping (up to 11 mole%) into SrRuO{sub 3} (SRO) thin films on SrTiO{sub 3} substrates decreased correlation lengths of both surface and interface. It turned out that Fe was doped in the valence state of 3+ without formation of the Fe{sub 2}O{sub 3} phase, which caused orthorhombic distortion. T{sub C} values decreased from 145 K to 97 K with increasing Fe concentration (C{sub Fe}). High magnetic switching fields were observed for all Fe-doped SRO thin films and their strengths showed a linear relationship with C{sub Fe}. Detail structural characterization using synchrotron X-ray diffraction and X-ray photoemission spectroscopy were used to understand its unique magnetic switching field properties. (orig.)

  1. Immobilization of actinide ions in thin layers of polypyrrole/polyacrylamidoglycolic acid (PPy/PAGA) composite. Application to the preparation of alpha spectrometry sources

    Energy Technology Data Exchange (ETDEWEB)

    Leroy, D.; Mignonsin, P.; Lambert, B. [Liege Univ. (Belgium). Coordination Chemistry and Radiochemistry; Martinot, L. [Liege Univ. (Belgium). Coordination Chemistry and Radiochemistry; Research Associate of the Inter-Univ., Brussels (Belgium). Inst. for Nuclear Sciences; Jerome, C.; Jerome, R. [Liege Univ. (BE). Center of Education and Research on Macromolecules (CERM)

    2002-07-01

    We propose a new fully aqueous electrochemical method for the preparation of high resolution alpha sources. Thin films of polypyrrole (PPy) are prepared by anodic electropolymerization, starting from aqueous solutions of the pyrrole monomer and an anionic polyelectrolyte which is able to complex actinide and play the role of PPy doping agent: polyacrylamidoglycolic acid (PAGA). These thin films can be prepared on various electrodes: stainless steel, platinum, glassy carbon and polyethylene doped by carbon-black. Peeling tests revealed their strong adhesion on stainless steel electrode. Alpha sources were prepared by simple immersion in actinide containing solutions. This easy process results in alpha sources with outstanding energy resolution (FWHM: around 9 keV for various isotopes). (orig.)

  2. Compositional and Structural Properties of TiO2-xNx Thin Films Deposited by Radio-Frequency Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    JING Shi-Wei; LIU Yi-Chun; LIANG Yu; MA Jian-Gang; LU You-Ming; SHEN De-Zhen; ZHANG Ji-Ying; FAN Xi-Wu; MU Ri-Xiang

    2006-01-01

    @@ TiO2-xNx thin films are deposited onto Si(100) and quartz substrates by a rf magnetron sputtering method using a titanium metal disc as a target in Ar, N2, and O2 atmospheres. The substrate temperature is kept at 300°C. The O2 and Ar gas flow rates are kept to be constants and the N gas flow rate is varied. TiO2-xNx films with different N contents are characterized by x-ray diffraction and x-ray photoelectron spectroscopy. The results indicate that the TiO2-xNx thin films can be obtained at 13% N and 15% N contents in the film, and the films with mixed TiO2 and TiN crystal can be obtained at 13% N and 15% N contents in the film. In terms of the results of x-ray photoelectron spectroscopy, N 1s of β-N (396 eV) is the main component in the TiO2-xNx thin films.

  3. Effect of Composition on Electrical and Optical Properties of Thin Films of Amorphous GaxSe100−x Nanorods

    Directory of Open Access Journals (Sweden)

    Abdallah El-Hamidy SM

    2010-01-01

    Full Text Available Abstract We report the electrical and optical studies of thin films of a-GaxSe100−x nanorods (x = 3, 6, 9 and 12. Thin films of a-GaxSe100−x nanorods have been synthesized thermal evaporation technique. DC electrical conductivity of deposited thin films of a-GaxSe100−x nanorods is measured as a function of temperature range from 298 to 383 K. An exponential increase in the dc conductivity is observed with the increase in temperature, suggesting thereby a semiconducting behavior. The estimated value of activation energy decreases on incorporation of dopant (Ga content in the Se system. The calculated value of pre-exponential factor (σ0 is of the order of 101 Ω−1 cm−1, which suggests that the conduction takes place in the band tails of localized states. It is suggested that the conduction is due to thermally assisted tunneling of the carriers in the localized states near the band edges. On the basis of the optical absorption measurements, an indirect optical band gap is observed in this system, and the value of optical band gap decreases on increasing Ga concentration.

  4. 界面缺陷对压电薄层复合结构中Love波的影响%Effect of interfacial defect on Love waves in composite structures with piezoelectric thin film

    Institute of Scientific and Technical Information of China (English)

    王惠明; 赵志城

    2012-01-01

    基于剪切弹簧模型,建立考虑界面缺陷情形的弹性基底上覆盖压电薄层的复合结构中Love波的频散方程,并研究界面缺陷对Love波传播特性的影响,给出铝基底上覆盖PZT4压电薄层复合结构中Love波的频散曲线.数值结果表明:(1)对于长波情形,不同缺陷程度复合结构的Love波一阶模态的相速度均趋于弹性基底层的剪切波波速,而对于短波情形,则趋于压电薄层的Bleustein-Gulyaev(B-G)波波速;(2)界面缺陷的存在总是降低该复合结构内Love波的相速度,在一些特殊频率范围,Love波的相速度对界面缺陷非常敏感;(3)界面缺陷对压电层内的机械位移模态和电势模态有显著影响,且影响最大区域出现在界面附近.%Based on the shear spring model, the dispersion equation was established for Love waves propagating in a composite structure with interfacial defect. The composite structure consists of an elastic substrate covered by a piezoelectric thin film. The effect of the interfacial defect on the propagation properties of Love waves was investigated. The dispersion curves were presented for Love waves propagating in an aluminum substrate covered by a PZT4 piezoelectric thin film. Numerical results show that; (1) For different interfacial defects, the phase velocities of Love waves of the first mode at long wavelength region approach to the velocities of shear waves in elastic substrate, while those at short wavelength region approach to the velocities of Bleustein-Gulyaev (B-G) waves in piezoelectric thin film; (2) The existence of the interfacial defect always decreases the phase velocities of Love waves. At some special frequency ranges, the phase velocities of Love waves are more sensitive to the interfacial defect; (3) The interfacial defect has significant effect on the mode shapes of the mechanical displacement and the electric potential in the piezoelectric thin film, and the most susceptive region appears near

  5. Influence of composition on optical and dispersion parameters of thermally evaporated non-crystalline Cd{sub 50}S{sub 50−x}Se{sub x} thin films

    Energy Technology Data Exchange (ETDEWEB)

    Hassanien, A.S., E-mail: a.s.hassanien@gmail.com [Engineering Mathematics and Physics Dept., Faculty of Engineering (Shoubra), Benha University (Egypt); Physics Department, Faculty of Science and Humanities in Ad-Dawadmi, Shaqra University, 11911 (Saudi Arabia); Akl, Alaa A. [Physics Department, Faculty of Science and Humanities in Ad-Dawadmi, Shaqra University, 11911 (Saudi Arabia)

    2015-11-05

    Non-crystalline thin films of chalcogenide Cd{sub 50}S{sub 50−x}Se{sub x} system (30 ≤ x ≤ 50) were obtained by thermal evaporation technique onto a pre-cleaned glass substrate at a vacuum of 8.2 × 10{sup −4} Pa. The deposition rate and film thickness were kept constant at about 8 nm/s and 200 nm, respectively. Amorphous/crystalline nature and chemical composition of films have been checked using X-ray diffraction and energy dispersive X-ray spectroscopy (EDX). Optical properties of thin films were investigated and studied using the corrected transmittance, T(λ) and corrected reflectance, R(λ) measurements. Obtained data reveal that, the indirect optical energy gap (E{sub g}) was decreased from 2.21 to 1.57 eV. On the contrary, Urbach energy (band tail width), E{sub U} was found to be increased from 0.29 to 0.45 eV. This behavior is believed to be associated with the increase of Se-content instead of S-content in the thin films of Cd{sub 50}S{sub 50−x}Se{sub x} system. Chemical bond approach model, CBA was used to analyze the obtained values of E{sub g} and E{sub U}. Optical density, skin depth, extinction coefficient, refractive index and optical conductivity of chalcogenide CdSSe thin films were discussed as functions of Se-content. Using Wemple-DiDomenico single oscillator model, the refractive index dispersion and energy parameters and their dependence on Se content were studied. - Highlights: • Amorphous thin films of thickness 200 nm of Cd{sub 50}S{sub 50−x}Se{sub x} (30 ≤ x ≤ 50) have prepared. • Optical properties, indirect optical energy gap and band tail width were studied. • Chemical bond approach, CBA was used to analyze the obtained values of E{sub g} and E{sub U}. • New data of dispersion refractive index parameters were investigated and discussed.

  6. Physical properties of nanostructured (PbS)x(CuS)1−x composite thin films grown by successive ionic layer adsorption and reaction method

    OpenAIRE

    UBALE, A. U.; M.V. Bhute; G.P. Malpe; Raut, P.P.; K.S. Chipade; S.G. Ibrahim

    2016-01-01

    Nanostructured ternary semiconducting (PbS)x(CuS)1−x thin films were grown on glass substrates by successive ionic layer adsorption and reaction (SILAR) technique at room temperature. The structural, morphological and optical characterizations of the films were carried out by X-ray diffraction, scanning electron microscopy and UV–Vis spectrophotometer respectively. The structural studies revealed that, (PbS)x(CuS)1−x films are nanocrystalline in nature and have mixed phase of cubic PbS and he...

  7. DEFORMATION INVESTIGATION ON iPP/SiO2 COMPOSITES: INFLUENCE OF STRETCHING TEMPERATURE AND PARTICLE SIZE ON MORPHOLOGY EVOLUTION AND CRYSTALLINE STRUCTURE OF THIN FILMS

    Institute of Scientific and Technical Information of China (English)

    Xiu-qin Zhang; Qian Xing; Rong-bo Li; Rui Wang; Du-jin Wang

    2013-01-01

    In the present work,structure changes during stretching of isotactic polypropylene (iPP) and iPP/silicon dioxide (SiO2) composites have been investigated systematically.The α-form crystal structure of both iPP and iPP/SiO2 composites is destroyed and transforms into the mesophase as the samples are stretched at a low temperature (35℃),while stretching at high temperatures (90℃ and 120℃) can restrain the appearance of defects and keep the perfection of crystal structure.FTIR results reveal that the stretching temperatures show no obvious difference of the effect on the orientation of pure iPP,however,the orientation of iPP/SiO2 composites is greatly changed by the tensile temperature.In the case of micron-sized SiO2 particles (average particle diameter d > 1 μm),the orientation of the composites is lower than that of pure iPP at all stretching temperatures.The above results suggest that the stretching temperature and the SiO2 particle size have great influence on the structure variation and orientation behavior of iPP/SiO2 composites.

  8. Compositional and electrical properties of line and planar defects in Cu(In,Ga)Se{sub 2} thin films for solar cells - a review

    Energy Technology Data Exchange (ETDEWEB)

    Abou-Ras, Daniel; Schmidt, Sebastian S.; Schaefer, Norbert; Kavalakkatt, Jaison; Rissom, Thorsten; Unold, Thomas; Mainz, Roland; Weber, Alfons [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109, Berlin (Germany); Kirchartz, Thomas [Forschungszentrum Juelich, Institut fuer Energie- und Klimaforschung (IEK-5), Photovoltaik, 52428, Juelich (Germany); Simsek Sanli, Ekin; Aken, Peter A. van [Max Planck Institute for Solid State Research, Heisenbergstrasse 1, 70569, Stuttgart (Germany); Ramasse, Quentin M. [SuperSTEM Laboratory, SciTech Daresbury Campus, Keckwick Lane, Daresbury, WA4 4AD (United Kingdom); Kleebe, Hans-Joachim [Technische Universitaet Darmstadt, Institut fuer Angewandte Geowissenschaften, Schnittspahnstrasse 9, 64287, Darmstadt (Germany); Azulay, Doron; Balberg, Isaac; Millo, Oded [Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem, 91904 (Israel); Cojocaru-Miredin, Oana [RWTH Aachen, Physikalisches Institut IA, Sommerfeldstr. 14, 52074, Aachen (Germany); Barragan-Yani, Daniel; Albe, Karsten [Technische Universitaet Darmstadt, FG Materialmodellierung, Jovanka-Bontschits-Str. 2, 64287, Darmstadt (Germany); Haarstrich, Jakob; Ronning, Carsten [Institut fuer Festkoerperphysik, Friedrich Schiller Universitaet Jena, Max-Wien-Platz 1, 07743, Jena (Germany)

    2016-05-15

    The present review gives an overview of the various reports on properties of line and planar defects in Cu(In,Ga)(S,Se){sub 2} thin films for high-efficiency solar cells. We report results from various analysis techniques applied to characterize these defects at different length scales, which allow for drawing a consistent picture on structural and electronic defect properties. A key finding is atomic reconstruction detected at line and planar defects, which may be one mechanism to reduce excess charge densities and to relax deep-defect states from midgap to shallow energy levels. On the other hand, nonradiative Shockley-Read-Hall recombination is still enhanced with respect to defect-free grain interiors, which is correlated with substantial reduction of luminescence intensities. Comparison of the microscopic electrical properties of planar defects in Cu(In,Ga)(S,Se){sub 2} thin films with two-dimensional device simulations suggest that these defects are one origin of the reduced open-circuit voltage of the photovoltaic devices. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Magnetic and structural characteristics of multiferroic Fe3O4/(Bi3.25Nd0.65Eu0.10)Ti3O12 composite thin films deposited by metalorganic chemical vapor deposition

    Science.gov (United States)

    Kobune, Masafumi; Furotani, Ryosuke; Fujita, Satoshi; Kikuchi, Kazuki; Kikuchi, Takeyuki; Fujisawa, Hironori; Shimizu, Masaru; Fukumuro, Naoki

    2016-10-01

    Ferromagnetic magnetite (Fe3O4) thin films for magnetoelectric multiferroic applications were deposited on (200) (Bi3.25Nd0.65Eu0.10)Ti3O12 (BNEuT)/(101) Nb:TiO2 substrates by metalorganic chemical vapor deposition (MOCVD) using an iron(III) tris(2,2,6,6-tetramethyl-3,5-heptanedionato) precursor as the iron source. The BNEuT film utilized as a ferroelectric template material was in the form of freestanding nanoplates with narrow spaces between them. The effects of deposition conditions such as the deposition time and substrate temperature on the magnetic and structural characteristics of the Fe3O4/BNEuT composite films were investigated. All the films consisted of mostly single-phase Fe3O4 with a cubic inverse-spinel structure. When deposition was carried out at temperatures of 400-420 °C, the filling rates of particles introduced into the narrow spaces between the BNEuT nanoplates exhibited high values of 76-89% including the amorphous phase. This suggested that the deposition in this temperature range made progress according to the growth mechanism of MOCVD in the surface reaction rate determining state. Room-temperature magnetic moment-magnetic field curves for Fe3O4 thin films deposited at 400-500 °C for 60 min exhibited narrow rectangular hysteresis loops, indicating typical soft magnetic characteristics.

  10. Improved Breakdown Voltage in AlGaN/GaN High Electron Mobility Transistors by Employing Polyimide/Chromium Composite Thin Films as Surface Passivation and High-Permittivity Field Plates

    Science.gov (United States)

    Chu, Fu-Tong; Chen, Chao; Zhou, Wei; Liu, Xing-Zhao

    2013-09-01

    The breakdown voltage of AlGaN/GaN high electron mobility transistors (HEMTs) is enhanced by employing metal chromium (Cr) nanoparticle-embedded polyimide (PI) as a high-permittivity (high-K) dielectric covering both the source-gate and gate-drain regions. The PI/Cr composite high-K dielectrics acting as a field plate prevent the occurrence of strong electric fields produced at the drain side edge of the gate electrode to obtain an optimum lateral electric flux of HEMTs. The breakdown voltage is improved by approximately 35% when using the PI/Cr thin film dielectric field plate while maintaining high performance, a high transconductance value of 122.4 mS/mm, and a large saturated drain-current value of 748 mA/mm.

  11. Characterization of sol-gel thin films of TiO2-PbO, TiO2-Bi2O3 and TiO2-CeO2 compositions

    Science.gov (United States)

    Aegerter, Michel A.; La Serra, Eliane R.; Martins Rodrigues, Ana C.; Kordas, George; Moore, Glenn A.

    1990-11-01

    Single and multilayer sol-gel thin films of Ti02-PbO, Ti02-Bi203 and Ti02-CeO2 composition were deposited on glasses using the dip coating technique. The precursors included Ti(OPri)4 chemically modified by acetyl acetone and diluted in PriOH and sols of Pb(OAc)2, Bi(NO3)3 5H20 diluted in acetic acid. The Ti02-Ce02 sol was prepared by mixing Ce NH2 (NO3 )6 in ethanol and then adding Ti (O-iso-C3H7 )4. Structure texture and homogeneity of their main constituants was established by XRD, XPS,SIMS and SEM-EDX techniques as a function of heat treatments.

  12. Thin book

    DEFF Research Database (Denmark)

    En lille bog om teater og organisationer, med bidrag fra 19 teoretikere og praktikere, der deltog i en "Thin Book Summit" i Danmark i 2005. Bogen bidrager med en state-of-the-art antologi om forskellige former for samarbejde imellem teater og organisationer. Bogen fokuserer både på muligheder og...

  13. Effect of boric acid composition on the properties of ZnO thin film nanotubes and the performance of dye-sensitized solar cell (DSSC)

    Energy Technology Data Exchange (ETDEWEB)

    Rahman, M.Y.A., E-mail: mohd.yusri@ukm.edu.my; Roza, L.; Umar, A.A., E-mail: akrajas@ukm.edu.my; Salleh, M.M.

    2015-11-05

    The effect of boric acid (H{sub 3}BO{sub 3}) composition at constant concentration of hexamethylenetetramine (HMT) and zinc nitrate (Zn(NO{sub 3}){sub 2}) on the morphology, thickness, elemental composition, optical absorption, structure, photoluminescence of ZnO nanotubes has been investigated. The performance of the DSSC utilizing the ZnO samples has also been studied. It was found that the structure, thickness, elemental composition, optical absorption and morphology of ZnO nanostructure are significantly affected by the concentration of H{sub 3}BO{sub 3}. The diameter and thickness of ZnO nanotubes decreases as the composition of H{sub 3}BO{sub 3} increases. The DSSC utilizing ZnO nanotubes synthesized at 2 wt. % H{sub 3}BO{sub 3} performs the highest J{sub SC} and η of 2.67 mA cm{sup −2} and 0.29%, respectively. The highest performance of the device is due to the highest optical absorption of ZnO nanotubes sample and lowest charge interfacial resistance. - Graphical abstract: Nyquist plots of the DSSCs utilizing ZnO nanotubes prepared at various boric acid compositions. - Highlights: • Boron was doped into ZnO films by adding H{sub 3}BO{sub 3} into the growth solution. • Diameter and thickness of ZnO nanotubes decreases with the composition of H{sub 3}BO{sub 3}. • The DSSC performs the highest J{sub SC} and η of 2.67 mA cm{sup −2} and 0.29%, respectively. • This is due to high specific surface area and low charge interfacial resistance.

  14. TiO{sub 2}/SiO{sub 2} porous composite thin films: Role of TiO{sub 2} areal loading and modification with gold nanospheres on the photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Levchuk, Irina, E-mail: irina.r.levchuk@gmail.com [Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Laboratoire de Chimie, ENS Lyon, CNRS, Universite Claude Bernard Lyon 1, Universite de Lyon, UMR 5182, 46 allee d’Italie, 69364 Lyon (France); Sillanpää, Mika [Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Guillard, Chantal [Institut de Recherches sur la Catalyse et l’Environnement, IRCELYON, CNRS—University of Lyon, 69100 (France); Gregori, Damia; Chateau, Denis; Parola, Stephane [Laboratoire de Chimie, ENS Lyon, CNRS, Universite Claude Bernard Lyon 1, Universite de Lyon, UMR 5182, 46 allee d’Italie, 69364 Lyon (France)

    2016-10-15

    Highlights: • Composite TiO{sub 2}/Au/SiO{sub 2} films were prepared by sol-gel. • Size of Au NPs was in range 5–7 nm. • Physico-chemical and photocatalytic properties of TiO{sub 2}/Au/SiO{sub 2} were tested. • After UVC treatment all coatings exhibit super-hydrophilic character. • Photocatalytic activity of thin films was associated with areal loading of TiO{sub 2}. - Abstract: The aim of the work was to study photocatalytic activity of composite TiO{sub 2}/Au/SiO{sub 2} thin films. Coatings were prepared using sol-gel technique. Physicochemical parameters of coatings were characterized using UV–vis spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), ellipsometry, tactile measurements, goniometry and diffuse reflectance measurements. The photocatalytic activity of the films was tested in batch mode using aqueous solution of formic acid. Changes of formic acid concentration were determined by means of high pressure liquid chromatography (HPLC). Increase of initial degradation rate of formic acid was detected for TiO{sub 2}/Au/SiO{sub 2} films with gold nanoparticle’s load 0.5 wt.% and 1.25 wt.%. However, deeper insights using more detailed characterization of these coatings demonstrated that the improvement of the photocatalytic activity is more probably attributed to an increase in the areal loading of TiO{sub 2}.

  15. Design and Preparation of Lightweight Composite Pressure Vessels with Ultra Thin Metal Liner%含超薄金属内衬轻量化复合材料压力容器的设计与制备

    Institute of Scientific and Technical Information of China (English)

    矫维成; 杨帆; 郝立峰; 徐忠海; 刘文博; 王荣国; 赫晓东

    2013-01-01

    In the development of the new energy cars, the rocket engine systems and the satellites, there are some special requirements, such as the high air tightness, the lightweight and the long-life, for the composite pressure vessels used to store the liquid propellant and high pressure gas. In this paper, a new method is proposed to design and prepare the lightweight composite pressure vessels with ultra thin metal liner. A characterization method for the slippage coefficient measurement between the fiber and the mandrel is developed. The Al alloy liners of 0.8mm in thickness are fabricated. A new stronger interface between the composite layer and the ultra thin Al alloy liner is designed according to the structure of the Gecko feet. A self-healing technology is adopted to improve the reusable properties. With the lightweight composite pressure vessels, the weight can be saved by 70% as compared to the metal pressure vessels with the same volume and the same pressure.%随着新能源汽车、火箭发动机系统、卫星等新技术和新装备的不断发展,对其携带液体燃料和高压气体的压力容器提出高气密、轻质量、长寿命的苛刻要求.对此,本文提出一种含超薄金属内衬轻量化复合材料压力容器的设计与制备技术.研究了缠绕纤维与芯模表面间滑线系数的表征方法,提出了基于工艺可实现的精密缠绕理论;研制出0.8mm厚超薄铝合金内衬;建立了仿壁虎脚结构的界面层设计理论模型,制备出超薄金属内衬与复合材料层间的超强界面层;掌握了复合材料结构的损伤自修复方法,提高了复合材料压力容器的可重复使用次数,所研制的轻量化复合材料压力容器相比同容积、同压力的金属容器减重70%.

  16. Axial compression behavior of square thin-walled steel tube-laminated bamboo composite hollow columns%薄壁方型钢管/竹胶板组合空芯柱轴心抗压性能

    Institute of Scientific and Technical Information of China (English)

    赵卫锋; 张武东; 周靖; 曹勇龙; 龙志林

    2014-01-01

    研究方形薄壁型钢管/多层竹胶板组合空芯柱(Square, thin-walled steel tube/multi-layered bamboo plywood composite hollow column,SBCC)的轴心抗压性能,揭示其受力破坏机理,为其工程应用提供试验和理论基础。考虑试件的截面尺寸、空心率及长细比对SBCC抗压承载力的影响,设计制作了15根轴心抗压试件,通过SBCC的抗压性能测试,考察测试过程中的破坏形态和变形特征,分析各因素对试件轴心抗压力学性能的影响规律。试验结果表明:SBCC轴心抗压失效主要有竹胶合板材料破坏、基体胶结面开胶破坏以及整体失稳破坏3种形态,总体上胶结面间的胶粘强度及长细比是决定破坏模式的主要因素。SBCC的轴心抗压承载力随组合柱竹净截面面积、空心率的增大而显著提高,随长细比的增大而降低。通过试验数据的非线性回归分析,建立了SBCC的轴心抗压承载力计算公式,公式估算结果与试验测试结果的误差在20%以内。该研究结果表明SBCC是一种轴心抗压性能较优异的钢/竹组合结构单元,可实现“以竹代木”,作为工程结构用材的应用前景广阔。%The development of laminated-bamboo has broadened the application range of bamboo material in the field of structural engineering. A new type of steel/laminated bamboo composite column was developed based on the existing bamboo composite element for constructing multi-story, pre-fabricated, column-supported, and bamboo-framed buildings, and named as square thin-walled steel tube/multi-layered bamboo plywood composite hollow column (SBCC). The core of the SBCC is a square thin-walled steel tube, and the exterior column consists of several high-strength bamboo plywood pieces (such as bamboo mat plywood) that are bonded together using a structural adhesive to form a composite hollow column. SBCCs are a new type of steel/bamboo composite with excellent physical and

  17. Composition-induced structural, electrical, and magnetic phase transitions in AX-type mixed-valence cobalt oxynitride epitaxial thin films

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Jumpei; Oka, Daichi [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu, Kawasaki 213-0012 (Japan); Hirose, Yasushi, E-mail: hirose@chem.s.u-tokyo.ac.jp; Yang, Chang; Fukumura, Tomoteru; Hasegawa, Tetsuya [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu, Kawasaki 213-0012 (Japan); CREST, Japan Science and Technology Agency, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Nakao, Shoichiro [Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu, Kawasaki 213-0012 (Japan); CREST, Japan Science and Technology Agency, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Harayama, Isao; Sekiba, Daiichiro [University of Tsukuba Tandem Accelerator Complex (UTTAC), 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577 (Japan)

    2015-12-07

    Synthesis of mid- to late-transition metal oxynitrides is generally difficult by conventional thermal ammonolysis because of thermal instability. In this letter, we synthesized epitaxial thin films of AX-type phase-pure cobalt oxynitrides (CoO{sub x}N{sub y}) by using nitrogen-plasma-assisted pulsed laser deposition and investigated their structural, electrical, and magnetic properties. The CoO{sub x}N{sub y} thin films with 0 ≤ y/(x + y) ≤ 0.63 grown on MgO (100) substrates showed a structural phase transition from rock salt (RS) to zinc blend at the nitrogen content y/(x + y) ∼ 0.5. As the nitrogen content increased, the room-temperature electrical resistivity of the CoO{sub x}N{sub y} thin films monotonically decreased from the order of 10{sup 5} Ω cm to 10{sup −4} Ω cm. Furthermore, we observed an insulator-to-metal transition at y/(x + y) ∼ 0.34 in the RS-CoO{sub x}N{sub y} phase, which has not yet been reported in Co{sup 2+}/Co{sup 3+} mixed-valence cobalt oxides with octahedral coordination. The low resistivity in the RS-CoO{sub x}N{sub y} phase, on the 10{sup −3} Ω cm order, may have originated from the intermediate spin state of Co{sup 3+} stabilized by the lowered crystal field symmetry of the CoO{sub 6−n}N{sub n} octahedra (n = 1, 2,…5). Magnetization measurements suggested that a magnetic phase transition occurred in the RS-CoO{sub x}N{sub y} films during the insulator-to-metal transition. These results demonstrate that low-temperature epitaxial growth is a promising approach for exploring novel electronic functionalities in oxynitrides.

  18. Compositional dependence of magnetization reversal mechanism, magnetic interaction and Curie temperature of Co{sub 1−x}Sr{sub x}Fe{sub 2}O{sub 4} spinel thin film

    Energy Technology Data Exchange (ETDEWEB)

    Ghasemi, Ali, E-mail: ali13912001@yahoo.com

    2015-10-05

    Highlights: • Nanoparticles and thin films of Co{sub 1−x}Sr{sub x}Fe{sub 2}O{sub 4} were successfully synthesized by a sol–gel process. • The value of strength of interaction was enhanced from −0.23 for x = 0 to −0.75 for x = 0.5. • The magnetization reversal process for x = 0, 0.1 was almost controlled by Kondorsky models. • The reversal mechanism for x = 0.2–0.5 obey the Stoner–Wohlfarth rule. - Abstract: Co{sub 1−x}Sr{sub x}Fe{sub 2}O{sub 4}, (x varies from 0 to 0.5 in a step of 0.1) nanoparticles were formed by means of sol–gel processing method. The morphological and structural features of nanoparticles were evaluated by Fourier transform infrared spectroscopy, field emission scanning electron microscopy (FE-SEM) equipped by EDS analysis, Mössbauer spectroscopy and vibrating sample magnetometer. It was found that almost narrow size distribution of nanoparticles with cation distribution occupancy preference in octahedral site was synthesized. The nanoparticles were used for addition in subsequent solution for fabricating ferrite thin films with similar mentioned chemical composition. Several techniques including FE-SEM, atomic force microscopy and vibrating sample magnetometer were employed to find the role of strontium cation distribution on the structural and magnetic properties of films. The Curie temperature, coercivity and magnetic interaction which was evaluated by Henkel plot were reduced by an increase in substitution contents. Coercivity of thin films reduced from 0.65 MA/m to 0.39 MA/m and Curie temperature declined from 690 to 455 °C. The value of strength of interaction was enhanced from −0.23 for x = 0 to −0.75 for x = 0.5. Angular dependence of coercivity proved that the magnetization reversal process was accompanied by the combination of domain wall motion and Stoner–Wohlfarth rotation, however for thin film with x = 0.2–0.5, the reversal mechanism obey the Stoner–Wohlfarth rule.

  19. Laser deposition and optical investigation of thin Ga(x)In(1-x)As(y)Sb(1-y) films of different compositions

    Energy Technology Data Exchange (ETDEWEB)

    Avdzhian, K.E.; Aleksanian, A.G.; Kazarian, R.K.; Matevosian, L.A.; Mirzabekian, G.E.

    1988-01-01

    Films of GaInAsSb solid solutions, obtained by the laser mixing method, are investigated. The lattice parameters and film compositions are determined, and the corresponding forbidden zone widths are found to be in good agreement with the values obtained in an optical study. The spectral dependence of the quantum well effect observed for a 29-nm-thick film is consistent with the analytical expression proposed here. 5 references.

  20. Study on the thin film composite poly(piperazine-amide) nanofiltration membranes made of different polymeric substrates: Effect of operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Misdan, Nurasyikin; Lau, Woei Jye; Ong, Chi Siang; Ismail, Ahmad Fauzi; Matsuura, Takeshi [Universiti Teknologi Malaysia, Skudai (Malaysia)

    2015-04-15

    Three composite nanofiltration (NF) membranes made of different substrate materials--polysulfone (PSf), polyethersulfone (PES) and polyetherimide (PEI)--were successfully prepared by interfacial polymerization technique. Prior to filtration tests, the composite NF membranes were characterized using field emission scanning electron microscope (FESEM), atomic force microscope (AFM) and X-ray photoelectron spectroscope (XPS). It was observed that the surface properties of composite NF membranes were obviously altered with the use of different substrate materials. The separation performance of the prepared composite NF membranes was further evaluated by varying operating conditions, which included feed salt concentration and operating temperature. Experimental results showed that the water flux of all TFC membranes tended to decrease with increasing Na{sub 2}SO{sub 4} concentration in feed solution, due to the increase in feed osmotic pressure. Of the three TFC membranes studied, PSf-based membrane demonstrated the highest salt rejection but lowest water flux owing to its highest degree of polyamide cross-linking as shown in XPS data. With respect to thermal stability, PEI-based TFC membrane outperformed the rest, overcoming the trade-off effect between permeability and rejection when the feed solution temperature was gradually increased from 30 .deg. C to 80 .deg. C. In addition, the relatively smoother surface of hydrophilic PEI-based membrane when compared with PSf-based membrane was found to be less susceptible to BSA foulants, leading to lower flux decline. This is because smoother surface of polyamide layer would have minimum 'valley clogging,' which improves membrane anti-fouling resistance.

  1. Effect of heat treatment on the structure and the thermoelectric properties of Sb0.9Bi1.1Te2.9Se0.1 thin films and composites based on them

    Science.gov (United States)

    Kalinin, Yu. E.; Kashirin, M. A.; Makagonov, V. A.; Pankov, S. Yu.; Sitnikov, A. V.

    2017-01-01

    This work considers the effect of vacuum annealing on the thermoelectric properties of Sb0.9Bi1.1Te2.9Se0.1 thin film and Sb0.9Bi1.1Te2.9Se0.1-C composites with various carbon contents produced by ion-beam deposition in an argon atmosphere. The electrical resistivity and the thermopower of Sb0.9Bi1.1Te2.9Se0.1-C nanocomposites are found to be dependent on not only the carbon concentration but also the type and the concentration of intrinsic point defects of the Sb0.9Bi1.1Te2.9Se0.1 solid solution, which determine the type of conductivity of Sb0.9Bi1.1Te2.9Se0.1 granules. The power factors are estimated for films of Sb0.9Bi1.1Te2.9Se0.1 solid solution and films of Sb0.9Bi1.1Te2.9Se0.1-C composites and found to have values comparable with the values for nanostructured materials on the basis of (Bi,Sb)2(Te,Se)3 solid solutions.

  2. Bath atomic composition and deposition time influence on the properties of nanostructured CdS{sub 0.5}Se{sub 0.5} thin films synthesized by CBD

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Ramirez, E.A. [Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, CP 07738 México D.F. (Mexico); Hernandez-Perez, M.A., E-mail: angeleshp@yahoo.com [Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, CP 07738 México D.F. (Mexico); Aguilar-Hernandez, J.R.; Contreras-Puente, G. [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, CP 07738 México D.F. (Mexico)

    2015-09-01

    Chemical Bath Deposition (CBD) was used to grow CdS{sub 1−xf}Se{sub xf} (x{sub f} = 0.5) thin films on Corning glass substrates at 75 °C. The atomic composition of the bath was varied until an x{sub f} of 0.5 was obtained, maintaining the deposition time at 120 min. Then the deposition time was modified from 5 to 360 min. The structural and optical properties of the films were analyzed by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction, UV–Vis Spectroscopy, Profilometry and Inductive Coupled Plasma-Optical Emission Spectroscopy (ICP-OES). A bath atomic composition of Cd:S:Se equal to 0.76:0.55:0.45 was employed to obtain a film of x{sub f} = 0.5. The films are constituted by clusters of semispherical nanoparticles (ϕ{sub av} = 15 nm), which are well-arranged in a “nanoworm” structure. The nucleation time of the particles is lower than 5 min. All the films are polycrystalline with hexagonal phase and preferentially orientated on the (002) plane. The crystal size (11–6 nm) and the band gap (2.17–1.99 eV) decrease with the content of Se and remain constant with the deposition time. The composition x{sub f} = 0.5 is achieved at different times to the heterogeneous (60 min) and homogeneous reactions (15 min). The kinetics of deposition and the consumption rate of Se change in a similar way, reaching the stability after 60 min. - Highlights: • CdS{sub 1−x}Se{sub x} ternary alloy thin films with x = 0.5 ± 0.05 can be grown by CBD at 75 °C. • CdS{sub 1−x}Se{sub x} nanocrystals are well arranged in a “worm” structure from 30 min and x ≥ 0.25. • The E{sub g} of (002) oriented hexagonal film is strongly affected by x and crystal size. • Films with x = 0.5 are obtained from 30 min using a Cd:S:Se = 0.76:0.5:0.6 bath ratio. • Consumption rate has the same behavior that growth rate, changing around 60 min.

  3. Host thin films incorporating nanoparticles

    Science.gov (United States)

    Qureshi, Uzma

    The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

  4. 大变形复合材料薄板多体系统动力学建模%Dynamic modeling of composite thin-plate multibody systems with large deformation

    Institute of Scientific and Technical Information of China (English)

    张炜华; 刘锦阳

    2016-01-01

    Dynamic modeling theory of composite thin-plate multibody systems with large deformation was investigated.Based on Kirchhoff's assumption that the normal vector is always perpendicular to the central surface,the relation among in-plane strains,curvatures,absolute nodal coordinates and absolute gradients were derived according to the definition of Green strain,and the generalized elastic-force vector and its differentiation with respect to the generalized coordinates were derived.Equations of motion of the composite thin-plate multibody systems with large deformation were derived based on absolute nodal-coordinate formulation.Generalized method and the Newton-Raphson method were used to solve the differential-algebraic equations.Simulation of a composite thin plate applied with an external force was conducted.Comparison of the present simulation results with those obtained by ANSYS software verifies the accuracy and effectiveness of the formulation.Finally,the proposed formulation is used for numerical simulation of composite solar-array deployment mechanisms.The vibration characteristics of the driving force and constraint forces are analyzed in case of different panel layers.%对大变形复合材料薄板的多体系统动力学建模方法进行研究。基于 Kirchhoff 假设,法线与中面保持垂直,从格林应变的表达式出发,建立了面内应变和曲率与绝对位置坐标和斜率的关系,在此基础上推导了广义弹性力阵和弹性力阵对广义坐标的导数阵,用绝对节点坐标方法建立了大变形复合材料薄板多体系统的动力学方程,用广义α法和和牛顿迭代法求解微分-代数混合方程。对外载荷作用下的复合材料薄板进行数值仿真,通过与 ANSYS 的仿真结果进行对比,验证了该建模方法的准确性和快速收敛性。最后,将建模方法应用于复合材料太阳帆板展开机构的数值仿真,分析了不同铺层情况下驱动力和约束力的振动特性。

  5. Thin film bismuth iron oxides useful for piezoelectric devices

    Energy Technology Data Exchange (ETDEWEB)

    Zeches, Robert J.; Martin, Lane W.; Ramesh, Ramamoorthy

    2016-05-31

    The present invention provides for a composition comprising a thin film of BiFeO.sub.3 having a thickness ranging from 20 nm to 300 nm, a first electrode in contact with the BiFeO.sub.3 thin film, and a second electrode in contact with the BiFeO.sub.3 thin film; wherein the first and second electrodes are in electrical communication. The composition is free or essentially free of lead (Pb). The BFO thin film is has the piezoelectric property of changing its volume and/or shape when an electric field is applied to the BFO thin film.

  6. Preparation and Optimization of Fluorescent Thin Films of Rosamine-SiO2/TiO2 Composites for NO2 Sensing

    Science.gov (United States)

    Guillén, María G.; Gámez, Francisco; Suárez, Belén; Queirós, Carla; Silva, Ana M. G.; Barranco, Ángel; Sánchez-Valencia, Juan Ramón; Pedrosa, José María; Lopes-Costa, Tânia

    2017-01-01

    The incorporation of a prototypical rosamine fluorescent dye from organic solutions into transparent and microstructured columnar TiO2 and SiO2 (MO2) thin films, prepared by evaporation at glancing angles (GAPVD), was evaluated. The aggregation of the adsorbed molecules, the infiltration efficiency and the adsorption kinetics were studied by means of UV-Vis absorption and fluorescence spectroscopies. Specifically, the infiltration equilibrium as well as the kinetic of adsorption of the emitting dye has been described by a Langmuir type adsorption isotherm and a pseudosecond order kinetic model, respectively. The anchoring mechanism of the rosamine to the MO2 matrix has been revealed by specular reflectance Fourier transform infrared spectroscopy and infiltration from aqueous solutions at different pH values. Finally, the sensing performance towards NO2 gas of optimized films has been assessed by following the changes of its fluorescence intensity revealing that the so-selected device exhibited improved sensing response compared to similar hybrid films reported in the literature. PMID:28772484

  7. Composition dependence of the ferroelectric properties of lanthanum-modified bismuth titanate thin films grown by using pulsed-laser deposition

    CERN Document Server

    Bu, S D; Park, B H; Noh, T W

    2000-01-01

    Lanthanum-modified bismuth titanate, Bi sub 4 sub - sub x La sub x Ti sub 3 O sub 1 sub 2 (BLT), thin films with a La concentration of 0.25<=x<=1.00 were grown on Pt/Ti/SiO sub 2 /Si substrates by using pulsed-laser deposition. The BLT films showed well-saturated polarization-electric field curves whose remnant polarizations were 16.1 mu C/cm sup 2 , 27.8 mu C/cm sup 2 , 19.6 mu C/cm sup 2 , and 2.7 mu C/cm sup 2 , respectively, for x=0.25, 0.05, 0.75, and 1.00. The fatigue characteristics became better with increasing x up to 0.75. The Au/BLT/Pt capacitor with a La concentration of 0.50 showed an interesting dependence of the remanent polarization on the number of repetitive read/write cycles. On the other hand, the capacitor with a La concentration of 0.75 showed fatigue-free characteristics.

  8. Finite-Size and Composition-Driven Topological Phase Transition in (Bi1-xInx)2Se3 Thin Films.

    Science.gov (United States)

    Salehi, Maryam; Shapourian, Hassan; Koirala, Nikesh; Brahlek, Matthew J; Moon, Jisoo; Oh, Seongshik

    2016-09-14

    In a topological insulator (TI), if its spin-orbit coupling (SOC) strength is gradually reduced, the TI eventually transforms into a trivial insulator beyond a critical point of SOC, at which point the bulk gap closes: this is the standard description of the topological phase transition (TPT). However, this description of TPT, driven solely by the SOC (or something equivalent) and followed by closing and reopening of the bulk band gap, is valid only for infinite-size samples, and little is known how TPT occurs for finite-size samples. Here, using both systematic transport measurements on interface-engineered (Bi1-xInx)2Se3 thin films and theoretical simulations (with animations in the Supporting Information), we show that description of TPT in finite-size samples needs to be substantially modified from the conventional picture of TPT due to surface-state hybridization and bulk confinement effects. We also show that the finite-size TPT is composed of two separate transitions, topological-normal transition (TNT) and metal-insulator transition (MIT), by providing a detailed phase diagram in the two-dimensional phase space of sample size and SOC strength.

  9. Non-conventional interaction contributions in permalloy/NiO composite thin films deduced from their static and dynamic magnetization behavior

    Energy Technology Data Exchange (ETDEWEB)

    Zighem, F; Roussigne, Y; Cherif, S-M; Moch, P [Laboratoire des Proprietes Mecaniques et Thermodynamiques des Materiaux, CNRS, Institut Galilee, Universite Paris-Nord, Avenue J-B Clement, 93430 Villetaneuse (France)], E-mail: zighem@galilee.univ-paris13.fr

    2008-03-26

    A comparative study of thin permalloy films (10.4 nm) interfaced with NiO layers of various thicknesses (6 to 47 nm) is presented. The magnetic parameters deduced from different experimental techniques (Brillouin spectroscopy, ferromagnetic resonance and magnetometric (vibrating sample magnetometry and magneto-optical Kerr effect) investigations) show original characteristics which have not been previously evidenced: (i) for most of the samples studied, the exchange bias field is not parallel or perpendicular to the cooling field, in contrast with the in-plane anisotropy field; (ii) the magnetic properties under an out-of-plane applied magnetic field H do not match the calculated ones derived from the usual expression for the density of magnetic energy. We introduce a phenomenological additional term proportional to cos[{alpha}] where {alpha} is the angle between H and the direction normal to the sample: this non-conventional interaction between NiO and permalloy layers allows us to fit all the experimental data.

  10. Preparation and Optimization of Fluorescent Thin Films of Rosamine-SiO2/TiO2 Composites for NO2 Sensing

    Directory of Open Access Journals (Sweden)

    María G. Guillén

    2017-01-01

    Full Text Available The incorporation of a prototypical rosamine fluorescent dye from organic solutions into transparent and microstructured columnar TiO2 and SiO2 (MO2 thin films, prepared by evaporation at glancing angles (GAPVD, was evaluated. The aggregation of the adsorbed molecules, the infiltration efficiency and the adsorption kinetics were studied by means of UV-Vis absorption and fluorescence spectroscopies. Specifically, the infiltration equilibrium as well as the kinetic of adsorption of the emitting dye has been described by a Langmuir type adsorption isotherm and a pseudosecond order kinetic model, respectively. The anchoring mechanism of the rosamine to the MO2 matrix has been revealed by specular reflectance Fourier transform infrared spectroscopy and infiltration from aqueous solutions at different pH values. Finally, the sensing performance towards NO2 gas of optimized films has been assessed by following the changes of its fluorescence intensity revealing that the so-selected device exhibited improved sensing response compared to similar hybrid films reported in the literature.

  11. Continuous-wave and Q-switched performance of an Yb:YAG/YAG composite thin disk ceramic laser pumped with 970-nm laser diode

    Institute of Scientific and Technical Information of China (English)

    Hong Cai; Jun Zhou; Hongming Zhao; Yunfeng Qi; Qihong Lou; Jingxing Dong; Yunrong Wei

    2008-01-01

    Using front face-pumped compact active mirror laser (CAMIL) structure, we have demonstrated an Yb:YAG/YAG composite ceramic disk laser with pumping wavelength at 970 nm. The laser has been operated in both continuous-wave (CW) and Q-switching modes. Under CW operation, laser output power of 1.05 W with 2% transmission output coupler was achieved at the wavelength of 1031 nm. Qswitched laser output was gotten by using an acousto-optic Q-switch. The repetition rate ranged from 1 to 30 kHz and the pulse width varied from 166 to 700 ns.

  12. Electrical Characterization of Cu Composition Effects in CdS/CdTe Thin-Film Solar Cells with a ZnTe:Cu Back Contact: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Li, J. V.; Duenow, J. N.; Kuciauskas, D.; Kanevce, A.; Dhere, R. G.; Young, M. R.; Levi, D. H.

    2012-07-01

    We study the effects of Cu composition on the CdTe/ZnTe:Cu back contact and the bulk CdTe. For the back contact, its potential barrier decreases with Cu concentration while its saturation current density increases. For the bulk CdTe, the hole density increases with Cu concentration. We identify a Cu-related deep level at {approx}0.55 eV whose concentration is significant when the Cu concentration is high. The device performance, which initially increases with Cu concentration then decreases, reflects the interplay between the positive influences and negative influences (increasing deep levels in CdTe) of Cu.

  13. Double junction photoelectrochemical solar cells based on Cu2ZnSnS4/Cu2ZnSnSe4 thin film as composite photocathode

    Science.gov (United States)

    Zhu, L.; Qiang, Y. H.; Zhao, Y. L.; Gu, X. Q.

    2014-02-01

    A solvothermal method was used to synthesize Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) nanoparticles. CZTS/CZTSe bilayer films have been fabricated via a layer-by-layer blade coating process on the fluorine dope tin oxide (FTO) substrates. We converted conventional dye-sensitized solar cells (DSSCs) into double junction photoelectrochemical solar cells with the replacement of the Pt-coated counter electrode with the as-prepared films as composite photocathodes. Compared with conventional DSSCs, the cells show an increased short circuit current and power conversion efficiency.

  14. Electrical and structural properties of a co-sputtered SiO{sub 2}-Pt composite thin film for an embedded resistor

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Seung-Kyu; Na, Seong-Hun; Park, Eun-Mi; Kim, Jin-Soo; Suh, Su-Jeong [Sungkyunkwan University, Suwon (Korea, Republic of)

    2012-10-15

    In this study, SiO{sub 2}-Pt nano-composite ceramic metal (cermet) was developed to control the resistivity and the temperature coefficient of resistance (TCR). The experiments were conducted under various Ar pressures to find the optimum conditions for high resistivity and low TCR. Pt particles were uniformly dispersed in the SiO{sub 2} matrix, and the number of Pt particles changed with the Ar pressure. A stable resistivity value of 880 ∼ 193820 μΩ-cm was obtained at 3 ∼ 20 mtorr, and the temperature coefficient of resistance was in the range of 383.189 ∼ -3229.14 ppm/K.

  15. A composite CdS thin film/TiO2 nanotube structure by ultrafast successive electrochemical deposition toward photovoltaic application

    Science.gov (United States)

    Fu, Han; Liu, Hong; Shen, Wenzhong

    2014-11-01

    Fabricating functional compounds on substrates with complicated morphology has been an important topic in material science and technology, which remains a challenging issue to simultaneously achieve a high growth rate for a complex nanostructure with simple controlling factors. Here, we present a novel simple and successive method based on chemical reactions in an open reaction system manipulated by an electric field. A uniform CdS/TiO2 composite tubular structure has been fabricated in highly ordered TiO2 nanotube arrays in a very short time period (~90 s) under room temperature (RT). The content of CdS in the resultant and its crystalline structure was tuned by the form and magnitude of external voltage. The as-formed structure has shown a quite broad and bulk-like light absorption spectrum with the absorption of photon energy even below that of the bulk CdS. The as-fabricated-sensitized solar cell based on this composite structure has achieved an efficiency of 1.43% without any chemical doping or co-sensitizing, 210% higher than quantum dot-sensitized solar cell (QDSSC) under a similar condition. Hopefully, this method can also easily grow nanostructures based on a wide range of compound materials for energy science and electronic technologies, especially for fast-deploying devices.

  16. A composite CdS thin film/TiO2 nanotube structure by ultrafast successive electrochemical deposition toward photovoltaic application.

    Science.gov (United States)

    Fu, Han; Liu, Hong; Shen, Wenzhong

    2014-01-01

    Fabricating functional compounds on substrates with complicated morphology has been an important topic in material science and technology, which remains a challenging issue to simultaneously achieve a high growth rate for a complex nanostructure with simple controlling factors. Here, we present a novel simple and successive method based on chemical reactions in an open reaction system manipulated by an electric field. A uniform CdS/TiO2 composite tubular structure has been fabricated in highly ordered TiO2 nanotube arrays in a very short time period (~90 s) under room temperature (RT). The content of CdS in the resultant and its crystalline structure was tuned by the form and magnitude of external voltage. The as-formed structure has shown a quite broad and bulk-like light absorption spectrum with the absorption of photon energy even below that of the bulk CdS. The as-fabricated-sensitized solar cell based on this composite structure has achieved an efficiency of 1.43% without any chemical doping or co-sensitizing, 210% higher than quantum dot-sensitized solar cell (QDSSC) under a similar condition. Hopefully, this method can also easily grow nanostructures based on a wide range of compound materials for energy science and electronic technologies, especially for fast-deploying devices.

  17. High-performance electrochromic device based on nanocellulose/polyaniline and nanocellulose/poly(3,4-ethylenedioxythiophene) composite thin films

    Science.gov (United States)

    Zhang, Sihang; Fu, Runfang; Du, Zoufei; Jiang, Mengjin; Zhou, Mi; Gu, Yingchun; Chen, Sheng

    2017-07-01

    With the development of nanotechnology, nanocomposite materials based on renewable resources are the focus of this research. Nanocellulose was prepared using sulfuric acid to swell cotton pulp, following with extensive ultrasonication. Nanocellulose/polyaniline (NC/PANI) and nanocellulose/poly(3,4-ethylenedioxythiophene) (NC/PEDOT) nanocomposites with core/shell structure were manufactured by in situ polymerization. The film-forming properties and electrochromic properties of PANI and PEDOT were significantly improved using the nanocellulose as matrix. NC/PANI and NC/PEDOT composite films were studied in single and dual electrochromic devices (ECDs). A viscous gel electrolyte (GE) was used in ECDs. The architectural design of single and dual device was ITO/NC-PANI/GE/ITO or ITO/NC-PEDOT/GE/ITO and ITO/NC-PANI/GE/NC-PEDOT/ITO, respectively. The dual ECD based on NC/PANI and NC/PEDOT composite films exhibited a higher color contrast (30.3%), shortest response time (1.5 s for bleaching and 1.9 s for coloring), largest coloration efficiency (241.6 C/cm2), and best cycling stability (over 150 cycles) compared with the single devices.

  18. Bi-layer channel structure-based oxide thin-film transistors consisting of ZnO and Al-doped ZnO with different Al compositions and stacking sequences

    Science.gov (United States)

    Cho, Sung Woon; Yun, Myeong Gu; Ahn, Cheol Hyoun; Kim, So Hee; Cho, Hyung Koun

    2015-03-01

    Zinc oxide (ZnO)-based bi-layers, consisting of ZnO and Al-doped ZnO (AZO) layers grown by atomic layer deposition, were utilized as the channels of oxide thin-film transistors (TFTs). Thin AZO layers (5 nm) with different Al compositions (5 and 14 at. %) were deposited on top of and beneath the ZnO layers in a bi-layer channel structure. All of the bi-layer channel TFTs that included the AZO layers showed enhanced stability (Δ V Th ≤ 3.2 V) under a positive bias stress compared to the ZnO single-layer channel TFT (Δ V Th = 4.0 V). However, the AZO/ZnO bi-layer channel TFTs with an AZO interlayer between the gate dielectric and the ZnO showed a degraded field effect mobility (0.3 cm2/V·s for 5 at. % and 1.8 cm2/V·s for 14 at. %) compared to the ZnO single-layer channel TFT (5.5 cm2/V·s) due to increased scattering caused by Al-related impurities near the gate dielectric/channel interface. In contrast, the ZnO/AZO bi-layer channel TFTs with an AZO layer on top of the ZnO layer exhibited an improved field effect mobility (7.8 cm2/V·s for 14 at. %) and better stability. [Figure not available: see fulltext.

  19. Composition and structural study of solution-processed Zn(S,O,OH) thin films grown using H{sub 2}O{sub 2} based deposition route

    Energy Technology Data Exchange (ETDEWEB)

    Buffière, M., E-mail: marie.buffiere@imec.be [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); 44Solar, 14 rue Kepler, 44240 La Chapelle-sur-Erdre (France); Gautron, E. [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Hildebrandt, T. [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP)-UMR 7174 EDF-CNRS-ENSCP, 6 quai Watier-78401 Chatou Cedex (France); Harel, S.; Guillot-Deudon, C.; Arzel, L. [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Naghavi, N. [Institut de Recherche et Développement sur l' Energie Photovoltaïque (IRDEP)-UMR 7174 EDF-CNRS-ENSCP, 6 quai Watier-78401 Chatou Cedex (France); Barreau, N. [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); Kessler, J. [Institut des Matériaux Jean Rouxel (IMN)-UMR 6502, Université de Nantes, CNRS, 2 rue de la Houssinière, BP 32229, 44322 Nantes Cedex 3 (France); 44Solar, 14 rue Kepler, 44240 La Chapelle-sur-Erdre (France)

    2013-05-01

    Recent results have revealed that the low deposition time issue of chemical bath deposited (CBD) Zn(S,O,OH) buffer layer used in Cu(In,Ga)Se{sub 2} (CIGSe) solar cells could be resolved using H{sub 2}O{sub 2} as an additive in the chemical bath solution. Although the use of this additive does not hinder the electrical properties of the resulting Zn(S,O,OH)-buffered CIGSe solar cells, the impact of H{sub 2}O{sub 2} on the Zn(S,O,OH) properties remains unclear. The present contribution aims at determining the chemical composition and the microstructure of Zn(S,O,OH) film deposited by CBD using the alternative deposition bath containing the standard zinc sulfate, thiourea, ammonia but also H{sub 2}O{sub 2} additive. Both X-ray photoemission spectroscopy and energy dispersive X-ray spectroscopy analyses reveal higher sulfur content in alternatively deposited Zn(S,O,OH), since the first step growth of the layer. According to transmission electron microscopy analyses, another consequence of the higher deposition rate achieved when adding H{sub 2}O{sub 2} in the bath is the modification of the absorber/buffer interface. This could be explained by the enhancement of the cluster growth mechanism of the layer. - Highlights: ► The Zn(S,O,OH) layer composition can vary with the chemical bath process used. ► The alternative process leads to a faster incorporation of sulfur in the layer. ► No ZnS epitaxial layer has been found at absorber/alternative buffer interface. ► The use of H{sub 2}O{sub 2} enhances the cluster-by-cluster growth mechanism.

  20. 薄壁钢板组合PEC柱(强轴)滞回性能试验研究%Hysteretic behavior of PEC columns (strong axis) with thin steel plate composite section

    Institute of Scientific and Technical Information of China (English)

    方有珍; 陆佳; 马吉; 孙国华

    2012-01-01

    目前我国规范关于PEC组合柱构件及由此组成的结构体系方面的有关内容还基本空白,通过了解国际上在PEC组合柱研究领域的现状,对3个变化混凝土强度等级和拉结筋间距的薄壁钢板组合截面PEC柱足尺试件在恒定轴压下进行水平循环荷载的滞回性能试验。观测记录各个试件加载阶段的薄壁钢板组合截面翼缘的局部屈曲和混凝土裂缝开裂与压溃现象,得到构件的荷载-位移滞回曲线。根据试验结果分析构件的承载力、抗侧刚度、构件的抗震延性和破坏模式等力学性能。结果表明:试验试件具有较好的变形能力和耗散地震能的双重功效;构件的破坏模式为薄壁钢板组合截面翼缘发生局部屈曲,随之柱脚部位混凝土压溃和拉结筋屈服甚至拉断。研究进一步丰富了PEC柱研究成果,为PEC组合柱组成的结构体系规范制订和工程应用提供了合理的理论依据。%According to the development in the field of partially encased composite columns (PEC) and the demand for modification of the relevant structural specification, PEC columns fabricated with thin-wall composite section were investigated. 3 specimens with various concrete strength and transverse link spacing were manufactured to represent the middle-storey column of a PEC column-steel beam composite frame structure. The test of the specimens were conducted under lateral cyclic loading along the strong axis with constant axial compression, and the hysteretic curves were obtained. Base on the test results, the global responses were analyzed, including the load-carrying capacity, lateral- resistant stiffness, energy-dissipation capacity, the ductility property and the failure mode. The specimens exhibited sound ductility and energy-dissipation capacity; the failure mode was primarily local buckling in the flange of a thin-wall composite section, crushing and spalling of concrete at the comer

  1. Aqueous-Processed Inorganic Thin-Film Solar Cells Based on CdSe(x)Te(1-x) Nanocrystals: The Impact of Composition on Photovoltaic Performance.

    Science.gov (United States)

    Zeng, Qingsen; Chen, Zhaolai; Zhao, Yue; Du, Xiaohang; Liu, Fangyuan; Jin, Gan; Dong, Fengxia; Zhang, Hao; Yang, Bai

    2015-10-21

    Aqueous processed nanocrystal (NC) solar cells are attractive due to their environmental friendliness and cost effectiveness. Controlling the bandgap of absorbing layers is critical for achieving high efficiency for single and multijunction solar cells. Herein, we tune the bandgap of CdTe through the incorporation of Se via aqueous process. The photovoltaic performance of aqueous CdSexTe1-x NCs is systematically investigated, and the impacts of charge generation, transport, and injection on device performance for different compositions are deeply discussed. We discover that the performance degrades with the increasing Se content from CdTe to CdSe. This is mainly ascribed to the lower conduction band (CB) of CdSexTe1-x with higher Se content, which reduces the driving force for electron injection into TiO2. Finally, the performance is improved by mixing CdSexTe1-x NCs with conjugated polymer poly(p-phenylenevinylene) (PPV), and power conversion efficiency (PCE) of 3.35% is achieved based on ternary NCs. This work may provide some information to further optimize the aqueous-processed NC and hybrid solar cells.

  2. Compositional Analysis of Electrodeposited Cu-Se Compound Semiconductor Thin Films Using Combined Voltammetry and Flow-Electrochemical Quartz Crystal Microgravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Wooju; Jeong, Seonghan; Myung, Noseung [Konkuk Univ., Chungju (Korea, Republic of); Rajeshwar, Krishnan [Univ. of Texas at Arlington, Arlington (United States); Lee, Chiwoo [Korea Univ., Seoul (Korea, Republic of)

    2013-10-15

    A novel method which is species selective for the compositional analysis of electrodeposited Cu-Se semiconductor films was developed using combined voltammetry and flow-EQCM. The amounts of free Se and Se in Cu{sub 2}Se were obtained from the frequency changes at constant potentials of -0.8 V and -3 V, respectively. Potential steps to -0.8 V and -1.3 V were employed to reduce free Se to Se{sub 2}{sup -} and Cu{sub 2}Se to Cu + Se{sub 2}{sup -}, respectively. Resultant total Cu was anodically stripped at +0.8 V and the free Cu content was calculated using the difference in frequency changes observed during the stripping of total Cu and Se in Cu{sub 2}Se. The results showed that the amounts of free Se, free Cu and the targeted Cu{sub 2}Se varied with deposition potential as well as film thickness. The ternary compound semiconductor CuInSe{sub 2} (CIS) has attracted great interest due to its unique properties and wide applications.

  3. An analysis of electrochemical energy storage using electrodes fabricated from atomically thin 2D structures of MoS2, graphene and MoS2/graphene composites

    Science.gov (United States)

    Huffstutler, Jacob D.

    The behavior of 2D materials has become of great interest in the wake of development of electrochemical double-layer capacitors (EDLCs) and the discovery of monolayer graphene by Geim and Novoselov. This study aims to analyze the response variance of 2D electrode materials for EDLCs prepared through the liquid-phase exfoliation method when subjected to differing conditions. Once exfoliated, samples are tested with a series of structural characterization methods, including tunneling electron microscopy, atomic force microscopy, Raman spectroscopy, and x-ray photoelectron spectroscopy. A new ionic liquid for EDLC use, 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate is compared in performance to 6M potassium hydroxide aqueous electrolyte. Devices composed of liquid-phase exfoliated graphene / MoS2 composites are analyzed by concentration for ideal performance. Device performance under cold extreme temperatures for the ionic fluid is presented as well. A brief overview of by-layer analysis of graphene electrode materials is presented as-is. All samples were tested with cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy, with good capacitive results. The evolution of electrochemical behavior through the altered parameters is tracked as well.

  4. TiO2/SiO2 porous composite thin films: Role of TiO2 areal loading and modification with gold nanospheres on the photocatalytic activity

    Science.gov (United States)

    Levchuk, Irina; Sillanpää, Mika; Guillard, Chantal; Gregori, Damia; Chateau, Denis; Parola, Stephane

    2016-10-01

    The aim of the work was to study photocatalytic activity of composite TiO2/Au/SiO2 thin films. Coatings were prepared using sol-gel technique. Physicochemical parameters of coatings were characterized using UV-vis spectrometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), ellipsometry, tactile measurements, goniometry and diffuse reflectance measurements. The photocatalytic activity of the films was tested in batch mode using aqueous solution of formic acid. Changes of formic acid concentration were determined by means of high pressure liquid chromatography (HPLC). Increase of initial degradation rate of formic acid was detected for TiO2/Au/SiO2 films with gold nanoparticle's load 0.5 wt.% and 1.25 wt.%. However, deeper insights using more detailed characterization of these coatings demonstrated that the improvement of the photocatalytic activity is more probably attributed to an increase in the areal loading of TiO2.

  5. Composition depth profiles of Bi{sub 3.15}Nd{sub 0.85}Ti{sub 3}O{sub 12} thin films studied by X-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Z.H. [Faculty of Material, Optoelectronic and Physics, Xiangtan University, Xiangtan 411105, Hunan (China); Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, Hunan (China); Zhong, X.L., E-mail: xlzhong@xtu.edu.cn [Faculty of Material, Optoelectronic and Physics, Xiangtan University, Xiangtan 411105, Hunan (China); Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, Hunan (China); Liao, H.; Wang, F. [Faculty of Material, Optoelectronic and Physics, Xiangtan University, Xiangtan 411105, Hunan (China); Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, Hunan (China); Wang, J.B., E-mail: jbwang@xtu.edu.cn [Faculty of Material, Optoelectronic and Physics, Xiangtan University, Xiangtan 411105, Hunan (China); Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, Hunan (China); Zhou, Y.C. [Faculty of Material, Optoelectronic and Physics, Xiangtan University, Xiangtan 411105, Hunan (China); Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Xiangtan University, Xiangtan 411105, Hunan (China)

    2011-06-15

    In the present work, X-ray photoelectron spectroscopy (XPS) was used to investigate the composition depth profiles of Bi{sub 3.15}Nd{sub 0.85}Ti{sub 3}O{sub 12} (BNT) ferroelectric thin film, which was prepared on Pt(1 1 1)/Ti/SiO{sub 2}/Si(1 0 0) substrates by chemical solution deposition (CSD). It is shown that there are three distinct regions formed in BNT film, which are surface layer, bulk film and interface layer. The surface of film is found to consist of one outermost Bi-rich region. High resolution spectra of the O 1s peak in the surface can be decomposed into two components of metallic oxide oxygen and surface adsorbed oxygen. The distribution of component elements is nearly uniform within the bulk film. In the bulk film, high resolution XPS spectra of O 1s, Bi 4f, Nd 3d, Ti 2p are in agreement with the element chemical states of the BNT system. The interfacial layer is formed through the interdiffusion between the BNT film and Pt electrode. In addition, the Ar{sup +}-ion sputtering changes lots of Bi{sup 3+} ions into Bi{sup 0} due to weak Bi-O bond and high etching energy.

  6. Hybrid organic/inorganic reverse osmosis (RO) membrane for bactericidal anti-fouling. 1. Preparation and characterization of TiO2 nanoparticle self-assembled aromatic polyamide thin-film-composite (TFC) membrane.

    Science.gov (United States)

    Kwak, S Y; Kim, S H; Kim, S S

    2001-06-01

    Hybrid organic/inorganic reverse osmosis (RO) membranes composed of aromatic polyamide thin films underneath titanium dioxide (TiO2) nanosized particles have been fabricated by a self-assembly process, aiming at breakthrough of biofouling problems. First, positively charged particles of the colloidal TiO2 were synthesized by a sol-gel process, and the diameter of the resulting particles in acidic aqueous solution was estimated to be approximately 2 nm by analyzing the UV-visible absorption characteristics with a quantum mechanical model developed by Brus. Transmission electron microscopy (TEM) further confirmed the formation of the quantum-sized TiO2 particles (approximately 10 nm or less). The TiO2 particles appeared to exist in the crystallographic form of anatase as observed with the X-ray diffraction (XRD) pattern in comparison with those of commercial 100% rutile and commercial 70:30% anatase-to-rutile mixture. The hybrid thin-film-composite (TFC) aromatic polyamide membranes were prepared by self-assembly of the TiO2 nanoparticles on the polymer chains with COOH groups along the surface. They showed improved RO performance in which the water flux even increased, though slightly. Field-emission scanning electron microscopy (FESEM) exhibited the TiO2 nanoparticles well adsorbed onto the surface. X-ray photoelectron spectroscopy (XPS) demonstrated quantitatively that a considerable amount of the adsorbed particles were tightly self-assembled at the expense of the initial loss of those that were loosely bound, and became stabilized even after exposure to the various washing and harsh RO operating conditions. The antibacterial fouling potential of the TiO2 hybrid membrane was examined and verified by measuring the viable numbers and determining the survival ratios of the Escherichia coli (E. coli) as a model bacterium, both with and without UV light illumination. The photocatalytic bactericidal efficiency was remarkably higher for the TiO2 hybrid membrane under UV

  7. TiO2-MoO3复合纳米管阵列薄膜的制备及其可见光活性%Preparation and Visible Light Photoelectrochemical Response of TiO2-MoO3 Composite Nanotube Thin Films

    Institute of Scientific and Technical Information of China (English)

    罗英; 崔晓莉; 解晶莹

    2011-01-01

    通过阳极氧化的方法制备TiO2纳米管薄膜,在MoO3存在的条件下对该薄膜进行热处理得到TiO2-MoO3复合纳米管阵列薄膜.利用X射线衍射(XRD),扫描电子显微镜(SEM),X射线光电子能谱(XPS),电化学阻抗谱(EIS),Mott-Schottky及光电化学方法对得到的薄膜进行了表征.XRD结果表明,TiO2-MoO3复合纳米管薄膜中的TiO2主要为锐钛矿晶型.SEM实验证实了薄膜纳米管结构的存在,样品中的MoO3均匀地分散在TiO2纳米管表面.利用XPS方法分析了TiO2-MoO3复合纳米管薄膜元素的组成,结果表明,MoO3在TiO2表面形成TiO2-MoO3复合纳米管薄膜.研究了热处理温度以及热处理时间对样品的光电化学性能的影响,相对于单纯TiO2纳米管薄膜,适量引入MoO3提高了样品在可见光区的光电响应能力,样品的平带电位负移.在450℃热处理60 min制得的TiO2-MoO3复合半导体纳米管阵列薄膜光电响应活性最高.%TiO2-MoO3 composite nanotube thin films were obtained by the thermal treatment of titanium dioxide nanotube thin films in the presence of MoO3.Titanium dioxide nanotubes (TiO2 NTs) thin films were prepared by the anodic oxidation of titanium foil.The resultant thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis, and photoelectrochemical methods.The XRD patterns showed that an anatase type TiO2was present in the thin films.Nanotube structures for the thin films were observed by SEM.MoO3 was dispersed on the TiO2 NT top surface.Elemental analysis by XPS showed that MoO3 recombined with the TiO2 NTs to form TiO2-MoO3 composite nanotube thin films.The influence of time and temperature of thermal treatment on the photoelectrochemical response for the TiO2-MoO3 composite nanotube thin film electrodes were investigated.The photoelectrochemical response of the TiO2-MoO3 composite

  8. Magnetostrictive thin films for microwave spintronics.

    Science.gov (United States)

    Parkes, D E; Shelford, L R; Wadley, P; Holý, V; Wang, M; Hindmarch, A T; van der Laan, G; Campion, R P; Edmonds, K W; Cavill, S A; Rushforth, A W

    2013-01-01

    Multiferroic composite materials, consisting of coupled ferromagnetic and piezoelectric phases, are of great importance in the drive towards creating faster, smaller and more energy efficient devices for information and communications technologies. Such devices require thin ferromagnetic films with large magnetostriction and narrow microwave resonance linewidths. Both properties are often degraded, compared to bulk materials, due to structural imperfections and interface effects in the thin films. We report the development of epitaxial thin films of Galfenol (Fe81Ga19) with magnetostriction as large as the best reported values for bulk material. This allows the magnetic anisotropy and microwave resonant frequency to be tuned by voltage-induced strain, with a larger magnetoelectric response and a narrower linewidth than any previously reported Galfenol thin films. The combination of these properties make epitaxial thin films excellent candidates for developing tunable devices for magnetic information storage, processing and microwave communications.

  9. Thin films under chemical stress

    Energy Technology Data Exchange (ETDEWEB)

    1991-01-01

    The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

  10. Pulsed laser deposition of ferroelectric thin films

    Science.gov (United States)

    Sengupta, Somnath; McKnight, Steven H.; Sengupta, Louise C.

    1997-05-01

    It has been shown that in bulk ceramic form, the barium to strontium ratio in barium strontium titanium oxide (Ba1- xSrxTiO3, BSTO) affects the voltage tunability and electronic dissipation factor in an inverse fashion; increasing the strontium content reduces the dissipation factor at the expense of lower voltage tunability. However, the oxide composites of BSTO developed at the Army Research Laboratory still maintain low electronic loss factors for all compositions examined. The intent of this study is to determine whether such effects can be observed in the thin film form of the oxide composites. The pulsed laser deposition (PLD) method has been used to deposit the thin films. The different compositions of the compound (with 1 wt% of the oxide additive) chosen were: Ba0.3Sr0.7TiO3, Ba0.4Sr0.6TiO3, Ba0.5Sr0.5TiO3, Ba0.6Sr0.4TiO3, and Ba0.7Sr0.3TiO3. The electronic properties investigated in this study were the dielectric constant and the voltage tunability. The morphology of the thin films were examined using the atomic force microscopy. Fourier transform Raman spectroscopy was also utilized for optical characterization of the thin films. The electronic and optical properties of the thin films and the bulk ceramics were compared. The results of these investigations are discussed.

  11. KH550-GO复合栅介质低压氧化物薄膜晶体管%Low-voltage oxide thin film transistor made of KH550-GO composite dielectrics

    Institute of Scientific and Technical Information of China (English)

    黄钰凯; 凌智勇; 邵枫; 温娟

    2016-01-01

    Spin coated-processed silane coupling agents (KH550-GO) composite proton conductor film shows a large specific gate capacitance of 2.18×10–6F/cm2due to the interfacial electric-double-layer effect. Low-voltage oxide (IZO) TFTs gated by a KH550-GO composite proton conductor film were self-assembled by only one shadow-mask. Electrical characteristics of the devices were measured by a Keithley 4200 SCS semiconductor parameter analyzer at room temperature under the condition of darkness. The results show that KH550-GO oxide thin film transistors possess good electrical properties, the operating voltage is only 2 V, the saturation current, the subthreshold gate voltage swing, the current on/off ratio, and the field-effect mobility are estimated to be 580 µA, 108 mV/dec, 4×107, and 16.7 cm2·V−1·s−1, respectively.%采用旋涂法制备硅烷偶联剂-氧化石墨烯(KH550-GO)新型复合栅介质薄膜,由于栅介质层和沟道层界面处明显的双电层效应,单位面积电容高达2.18×10–6 F/cm2。通过自组装法,借助磁控溅射仪,仅需一次掩膜,即可同时生成晶体管的沟道与源漏电极。利用半导体参数分析仪在室温黑暗的条件下测量该晶体管的电学特性,结果表明,KH550-GO栅介质氧化物薄膜晶体管具有优良的电学性能,其工作电压仅为2 V、饱和电流为580µA、亚阈值摆幅108 mV/dec、开关比4×107、场效应迁移率16.7 cm2·V−1·s−1。

  12. Conductive polymer/fullerene blend thin films with honeycomb framework for transparent photovoltaic application

    Energy Technology Data Exchange (ETDEWEB)

    Cotlet, Mircea; Wang, Hsing-Lin; Tsai, Hsinhan; Xu, Zhihua

    2015-04-21

    Optoelectronic devices and thin-film semiconductor compositions and methods for making same are disclosed. The methods provide for the synthesis of the disclosed composition. The thin-film semiconductor compositions disclosed herein have a unique configuration that exhibits efficient photo-induced charge transfer and high transparency to visible light.

  13. Thin Film Composite Materials, Phase 2

    Science.gov (United States)

    1987-01-01

    were Kevlar coated with silicone, EPDM , or neoprene rubber, with the following results: 1. Tensile testing of coated Kevlar fabric is very difficult...materials. 2. A method was developed for measuring water vapor permeability. Neoprene and EPDM are promising as coatings with good water resistance; however...control the folding of the fabric, since the diameters of the spiral channel will be fixed. Because of the stability imparted by the channel, it is

  14. Seismic Behavior of Thin-Walled C Steel-Bamboo Plywood Composite Column%薄壁C型钢—竹胶板组合箱型柱抗震性能试验

    Institute of Scientific and Technical Information of China (English)

    蒋天元; 李玉顺; 单炜; 张王丽

    2011-01-01

    提出了一种新型的组合柱—以两块薄壁C型钢为基本骨架口对口拼接,在型钢腹板及翼缘处用结构胶黏剂黏结4块竹帘胶合板,形成截面形式为箱型的薄壁C型钢—竹胶板组合柱.以钢板厚度、长细比、轴压比等为基本参数,对5根组合柱进行了拟静力加载试验,观察组合柱在不同参数设置下的钢板、竹胶板的应变变化和荷载—位移滞回曲线,得到了组合柱的承载力指标和耗能系数、延性系数等抗震性能指标,在此基础上进行了组合柱的承载力计算方法分析.结果表明,长细比和钢板厚度对钢—竹组合柱加载初期的受力性能影响不明显,但影响柱子的后期极限承载力和刚度,而轴压比对组合柱的极限承载力和延性性能起着决定作用.根据钢—竹组合柱在弹性阶段的轴压力大小和应力—应变关系,提出了组合柱的力学简化模型及屈服承载力计算方法,其计算结果与试验值吻合较好.%The paper presents a new type of composite column composed by gluing four pieces of bamboo plywood on the surface of box columns and two pieces of thin-walled C steel spliced mouth to mouth in the core. Pseudo-static tests on a total of 5 composite columns were conducted in terms of steel sheet thickness, slenderness ratio and axial compression ratio of the columns. The bearing capacity, dissipative coefficient, ductility, and other indexes about seismic performance were ac quired by analyzing the changes of strain in the steel sheets and bamboo plates and the load-displacement hysteretic curves under different parameters. Result shows that slenderness ratio and steel sheet thickness have little effect on the mechanical behaviors of initial load, but have effect on ultimate strength and stiffness under load imposed in the late period. Axial compression ratio makes a great dif ?rence in bearing capability and ductility performances of these columns. Based on the measurement of

  15. Preparation and Optical Absorption of Fe Implanted Composite Titania Thin Films%Fe离子注入二氧化钛复合薄膜制备及光吸收性能研究

    Institute of Scientific and Technical Information of China (English)

    周艳军; 何芳; 王玉林; 黄远; 万怡灶

    2011-01-01

    By uainS the sol-Sel method, TiO2 thin films were fabricated onto quartz aubatrates, and then modified by Fe introduced with ion implantation method to promote the ahsorption shift to visible region and enhance optical absorption of TiO2 thin films.XRD,XPS and UV-via were used to characterize the phase structure, the atomic chemical states and optical absorption of these composite TiO2 thin films in different implantation dose.The XRD results indicated that TiO2 films obtained by sol-gel method were anatase.Fe implantation reaulted in the disappearance of anatase and the occurrence of rutile.Since Fe3+ substituted Ti4+ in unit cell, so there was a solid solution of iron in TiO2 matrix.As a result, oxygen vacancies facilitated the transformation of TiO2 from anatase to rutile.XPS results revealed that Fe existed as elemental Fe and Fe3O4 in the films, indicating that the Ti in the lattice of TiO2 was aubatituted by Fe ion.However, No diffraction peaka of Fe and its oxidea were observed, ahowing their non-crystalline structures.The UV-VIS reaults of Fe-implanted TiO2 films with various Fe doae exhibited that the absorption edge shifted to a longer wavelengh due to the exiatence of Fe3O4.Furthermore , this red ahift increased with a higher implanted Fe doae and the optimal Fe implantation dose 1 × 1017 cm -2 was detennined accordingly.%采用溶胶凝胶法在石英基体上制备了纯TiO2薄膜,并通过离子注入方法对TiO2薄膜进行Fe掺杂改性以促进TiO2薄膜光吸收边红移,提高其光吸收性能.利用XRD,XPS及UV-vis对不同注入剂量的Fe掺杂TiO2复合薄膜的晶相结构、原子化学态以及光吸收性能进行了表征.XRD侧试结果表明,溶胶凝胶法制得的TiO2薄膜为锐钛矿相,经Fe离子注入后,复合TiO2薄膜经退火后锐钛矿相消失,金红石相出现,因为Fe3+离子进入晶胞代替Ti4+,在TiO2基体形成铁的固溶体,结果氧空缺形成促进了TiO2从锐钛矿向金红石的转变;XPS测试结果

  16. Thin film processes II

    CERN Document Server

    Kern, Werner

    1991-01-01

    This sequel to the 1978 classic, Thin Film Processes, gives a clear, practical exposition of important thin film deposition and etching processes that have not yet been adequately reviewed. It discusses selected processes in tutorial overviews with implementation guide lines and an introduction to the literature. Though edited to stand alone, when taken together, Thin Film Processes II and its predecessor present a thorough grounding in modern thin film techniques.Key Features* Provides an all-new sequel to the 1978 classic, Thin Film Processes* Introduces new topics, and sever

  17. Pyrolyzed thin film carbon

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  18. 3,5-二氧基苯甲酰哌嗪和均苯三甲酰氯界面聚合法制备复合纳滤膜%Preparation of Thin Film Composite Nanofiltration Membrane by Interfacial Polymerization with 3,5-Diaminobenzoylpiperazine and Trimesoyl Chloride

    Institute of Scientific and Technical Information of China (English)

    王丽红; 李德玲; 程丽华; 张林; 陈欢林

    2011-01-01

    A new aromatic diamine, 3,5-diaminobenzoylpiperazine (3,5-DABP), was synthesized from 3,5-diaminobenzoic acid and l-formyl piperazine. The structure of 3,5-DABP was identified by FT-IR spectra and 1H NMR spectra.With 3,5-DABP as aqueous monomer and trimesoyl chloride (TMC) as organic monomer, thin film composite (TFC) nanofiltration membranes were prepared by interfacial polymerization technology. The salt rejection order of these TFC membranes is Na2SO4>MgSO4>MgCl2>NaCl. This sequence indicates that the membranes are negatively charged.

  19. Thermochemical Analysis of Molybdenum Thin Films on Porous Alumina.

    Science.gov (United States)

    Lee, Kyoungjin; de Lannoy, Charles-François; Liguori, Simona; Wilcox, Jennifer

    2017-01-12

    Molybdenum (Mo) thin films (thickness thin-film composites were stable below 300 °C but had no reactivity toward gases. Mo thin films showed nitrogen incorporation on the surface as well as in the subsurface at 450 °C, as confirmed by X-ray photoelectron spectroscopy. The reactivity toward nitrogen was diminished in the presence of CO2, although no carbon species were detected either on the surface or in the subsurface. The Mo thin films have a very stable native oxide layer, which may further oxidize to higher oxidation states above 500 °C due to the reaction with the porous anodized alumina substrate. The oxidation of Mo thin films was accelerated in the presence of oxidizing gases. At 600 °C in N2, the Mo thin film on anodized alumina was completely oxidized and may also have been volatilized. The results imply that choosing thermally stable and inactive porous supports and operating in nonoxidizing conditions below 500 °C will likely maintain the stability of the Mo composite. This study provides key information about the chemical and structural stability of a Mo thin film on a porous substrate for future membrane applications and offers further insights into the integrity of thin-film composites when exposed to harsh conditions.

  20. Thin Ice Films at Mineral Surfaces.

    Science.gov (United States)

    Yeşilbaş, Merve; Boily, Jean-François

    2016-07-21

    Ice films formed at mineral surfaces are of widespread occurrence in nature and are involved in numerous atmospheric and terrestrial processes. In this study, we studied thin ice films at surfaces of 19 synthetic and natural mineral samples of varied structure and composition. These thin films were formed by sublimation of thicker hexagonal ice overlayers mostly produced by freezing wet pastes of mineral particles at -10 and -50 °C. Vibration spectroscopy revealed that thin ice films contained smaller populations of strongly hydrogen-bonded water molecules than in hexagonal ice and liquid water. Thin ice films at the surfaces of the majority of minerals considered in this work [i.e., metal (oxy)(hydr)oxides, phyllosilicates, silicates, volcanic ash, Arizona Test Dust] produced intense O-H stretching bands at ∼3400 cm(-1), attenuated bands at ∼3200 cm(-1), and liquid-water-like bending band at ∼1640 cm(-1) irrespective of structure and composition. Illite, a nonexpandable phyllosilicate, is the only mineral that stabilized a form of ice that was strongly resilient to sublimation in temperatures as low as -50 °C. As mineral-bound thin ice films are the substrates upon which ice grows from water vapor or aqueous solutions, this study provides new constraints from which their natural occurrences can be understood.

  1. Antimicrobial activity of biopolymer–antibiotic thin films fabricated by advanced pulsed laser methods

    Energy Technology Data Exchange (ETDEWEB)

    Cristescu, R., E-mail: rodica.cristescu@inflpr.ro [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Popescu, C.; Dorcioman, G.; Miroiu, F.M.; Socol, G.; Mihailescu, I.N. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, P.O. Box MG-36, Bucharest-Magurele (Romania); Gittard, S.D.; Miller, P.R.; Narayan, R.J. [Biomedical Engineering, University of North Carolina and North Carolina State University, Chapel Hill, NC 27599-7575 (United States); Enculescu, M. [National Institute for Materials Physics, PO Box MG-7, Bucharest-Magurele (Romania); Chrisey, D.B. [Tulane University, Department of Physics and Engineering Physics, New Orleans, LA (United States)

    2013-08-01

    We report on thin film deposition by matrix assisted pulsed laser evaporation (MAPLE) of two polymer–drug composite thin film systems. A pulsed KrF* excimer laser source (λ = 248 nm, τ = 25 ns, ν = 10 Hz) was used to deposit composite thin films of poly(D,L-lactide) (PDLLA) containing several gentamicin concentrations. FTIR spectroscopy was used to demonstrate that MAPLE-transferred materials exhibited chemical structures similar to those of drop cast materials. Scanning electron microscopy data indicated that MAPLE may be used to fabricate thin films of good morphological quality. The activity of PDLLA–gentamicin composite thin films against Staphylococcus aureus bacteria was demonstrated using drop testing. The influence of drug concentration on microbial viability was also assessed. Our studies indicate that polymer–drug composite thin films prepared by MAPLE may be used to impart antimicrobial activity to implants, medical devices, and other contact surfaces.

  2. Multifunctional Metal Matrix Composite Filament Wound Tank Liners Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Metal Matrix Composite (MMC) materials offer tremendous potential for lightweight propellant and pressurant tankage for space applications. Thin MMC liners for COPVs...

  3. 稀土对金属纳米粒子-介质复合薄膜(Ag-BaO)光电发射性能的增强%ENHANCED PHOTOEMISSION FROM METAL NANOPARTICLE COMPOSITE THIN FILMS (Ag-BaO) DOPED WITH RARE-EARTH ELEMENTS

    Institute of Scientific and Technical Information of China (English)

    许北雪; 吴锦雷; 刘惟敏; 杨海; 邵庆益; 刘盛; 薛增泉; 吴全德

    2001-01-01

    用真空蒸发沉积的方法制备了掺杂稀土的金属纳米粒子-介质复 合薄膜(Ag-BaO薄膜). 与不掺杂稀土的Ag-BaO薄膜相比,其光电发射能力提高了近40%. 透射电镜分析表明,掺杂稀土后,Ag-BaO薄膜中的Ag纳米粒子明显细化、球化、密度增大 . 这表明Ag纳米粒子的细化,使得其在光作用下,光电子更容易通过隧道效应穿过界面位垒 逸出,导致光电发射能力增强.%A metal nanoparticles-composite thin film (Ag-BaO), doped by rare-earth eleme nts, was g rown by vacuum deposition. Compared with the normal Ag-BaO thin film, the photo emission current of the doped Ag-BaO thin film increases by about 40%. The tran smi ssion electron micrograph indicated that Ag nanoparticles become smaller when do ped with rare-earth. With the smaller size of Ag nanoparticles, photoelect rons are eas ier to transgress from Ag nanoparticles via tunnel effect. Thus the photomission current increases.

  4. Cell adhesion to cathodic arc plasma deposited CrAlSiN thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sun Kyu, E-mail: skim@ulsan.ac.kr [School of Materials Science and Engineering, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Pham, Vuong-Hung [Department of Materials Science and Engineering, Seoul National University, Seoul 151-744 (Korea, Republic of); Kim, Chong-Hyun [Department of Food Science, Cornell University, Ithaca, NY 14853 (United States)

    2012-07-01

    Osteoblast cell response (cell adhesion, actin cytoskeleton and focal contact adhesion as well as cell proliferation) to CrN, CrAlSiN and Ti thin films was evaluated in vitro. Cell adhesion and actin stress fibers organization depended on the film composition significantly. Immunofluorescent staining of vinculin in osteoblast cells showed good focal contact adhesion on the CrAlSiN and Ti thin films but not on the CrN thin films. Cell proliferation was significantly greater on the CrAlSiN thin films as well as on Ti thin films than on the CrN thin films.

  5. Fracture of composite-adhesive-composite systems

    Science.gov (United States)

    Ripling, E. J.; Santner, J. S.; Crosley, P. B.

    1984-01-01

    This program was undertaken to initiate the development of a test method for testing adhesive joints in metal-adhesive-composite systems. The uniform double cantilever beam (UDCB) and the width tapered beam (WTB) specimen geometries were evaluated for measuring Mode I fracture toughness in these systems. The WTB specimen is the preferred geometry in spite of the fact that it is more costly to machine than the UDCB specimen. The use of loading tabs attached to thin sheets of composites proved to be experimentally unsatisfactory. Consequently, a new system was developed to load thin sheets of adherends. This system allows for the direct measurement of displacement along the load line. In well made joints separation occurred between the plies rather than in the adhesive.

  6. 分层损伤和完好复合材料薄壁加筋板的后屈曲承载能力及破坏形式%Post-bucking Carrying Capacity and Failure Modes of Composite Thin-wall Stiffened Panels with and without Damage

    Institute of Scientific and Technical Information of China (English)

    谢紫龙; 尚柏林; 常飞; 杨哲; 尹俊杰

    2013-01-01

    Delamination damage was prefabricated on composite thin-wall stiffened panels used in advanced aircraft by impact test,and then the buckling,post-buckling carrying capacity and failure modes of the samples with and without damage at shear load were studied by shear tests.The result show that the delamination damage could reduce the stiffness of the composite thin-wall stiffned panel and change its failure mode,and cause the obvious local buckling appearing during shear process,and thus greatly reduced bucking,post-bucking and damage loads.%利用冲击试验对先进飞机上常用的复合材料薄壁加筋板预制分层损伤,通过剪切试验研究了完好试样和损伤试样在剪切载荷下的屈曲、后屈曲承载能力及破坏形式.结果表明:分层损伤会降低复合材料薄壁加筋板的刚度,并改变其破坏形式,使其在剪切过程中出现明显的局部屈曲,进而大大降低其屈曲失稳载荷、后屈曲承载载荷和破坏载荷.

  7. Inorganic and Organic Solution-Processed Thin Film Devices

    Institute of Scientific and Technical Information of China (English)

    Morteza Eslamian

    2017-01-01

    Thin films and thin film devices have a ubiquitous presence in numerous conventional and emerging tech-nologies. This is because of the recent advances in nanotechnology, the development of functional and smart materials, conducting polymers, molecular semiconductors, carbon nanotubes, and graphene, and the employment of unique prop-erties of thin films and ultrathin films, such as high surface area, controlled nanostructure for effective charge transfer, and special physical and chemical properties, to develop new thin film devices. This paper is therefore intended to provide a concise critical review and research directions on most thin film devices, including thin film transistors, data storage memory, solar cells, organic light-emitting diodes, thermoelectric devices, smart materials, sensors, and actuators. The thin film devices may consist of organic, inorganic, and composite thin layers, and share similar functionality, properties, and fabrication routes. Therefore, due to the multidisciplinary nature of thin film devices, knowledge and advances already made in one area may be applicable to other similar areas. Owing to the importance of developing low-cost, scalable, and vacuum-free fabrication routes, this paper focuses on thin film devices that may be processed and deposited from solution.

  8. Sandwiched composites in aerospace engineering

    OpenAIRE

    Nunes, J. P.; Silva,J.F.

    2016-01-01

    This chapter considers sandwiched composites used in aerospace applications. Typical sandwich composites consist of two thin, stiff, high-strength facing skins separated by a thick and light core. New developments in the type of face and core materials, production methods and joining and repair techniques are discussed in this chapter. It also discusses various properties as well as their main design methods for existing and future applications of sandwiched composites.

  9. SUPER-THIN COATING MATERIAL FOR HIGH-GRADE HIGHWAY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The road surface of cement concrete in highway is easily cracked and even destroyed due to inhomogeneous subsiding of the road foundation. In this work, a super-thin-coating material is prepared in order to repair the destroyed thin road surface, in which polymers and steel-fibers are added into ordinary concrete to form a steel fiber reinforced polymer-cement-based composite. the composite was successfully used to repair road surface. Microstructure and mechanical properties of the composites are measured and analyzed.

  10. 'Active' Thin Sections

    NARCIS (Netherlands)

    De Rooij, M.R.; Bijen, J.M.J.M.

    1999-01-01

    Optical microscopy using thin sections has become more and more important over the last decade to study concrete. Unfortunately, this technique is not capable of studying actually hydrating cement paste. At Delft University of Technology a new technique has been developed using 'active' thin section

  11. Tungsten-doped thin film materials

    Science.gov (United States)

    Xiang, Xiao-Dong; Chang, Hauyee; Gao, Chen; Takeuchi, Ichiro; Schultz, Peter G.

    2003-12-09

    A dielectric thin film material for high frequency use, including use as a capacitor, and having a low dielectric loss factor is provided, the film comprising a composition of tungsten-doped barium strontium titanate of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3, where X is between about 0.5 and about 1.0. Also provided is a method for making a dielectric thin film of the general formula (Ba.sub.x Sr.sub.1-x)TiO.sub.3 and doped with W, where X is between about 0.5 and about 1.0, a substrate is provided, TiO.sub.2, the W dopant, Ba, and optionally Sr are deposited on the substrate, and the substrate containing TiO.sub.2, the W dopant, Ba, and optionally Sr is heated to form a low loss dielectric thin film.

  12. Thin Film & Deposition Systems (Windows)

    Data.gov (United States)

    Federal Laboratory Consortium — Coating Lab: Contains chambers for growing thin film window coatings. Plasma Applications Coating Lab: Contains chambers for growing thin film window coatings. Solar...

  13. Thin Film & Deposition Systems (Windows)

    Data.gov (United States)

    Federal Laboratory Consortium — Coating Lab: Contains chambers for growing thin film window coatings. Plasma Applications Coating Lab: Contains chambers for growing thin film window coatings. Solar...

  14. Flexural modulus identification of thin polymer sheets

    Science.gov (United States)

    Gluhihs, S.; Kovalovs, A.; Tishkunovs, A.; Chate, A.

    2011-06-01

    The method of determination of the flexural Young's modulus is based on a solution to the problem of compression of a thin-walled cylindrical specimen by two parallel planes (TWCS method). This method was employed to calculate the flexural modulus for PET polymer compositions. The flexural modules received by TWCS method were verified by comparing the experimentally measured eigenfrequencies by Polytec vibrometer with numerical results from ANSYS program.

  15. Flexural modulus identification of thin polymer sheets

    Energy Technology Data Exchange (ETDEWEB)

    Gluhihs, S; Kovalovs, A; Tishkunovs, A; Chate, A, E-mail: s_gluhih@inbox.lv [Riga Technical University, Institute of Materials and Structures, Azenes 16/22, LV-1048, Riga (Latvia)

    2011-06-23

    The method of determination of the flexural Young's modulus is based on a solution to the problem of compression of a thin-walled cylindrical specimen by two parallel planes (TWCS method). This method was employed to calculate the flexural modulus for PET polymer compositions. The flexural modules received by TWCS method were verified by comparing the experimentally measured eigenfrequencies by Polytec vibrometer with numerical results from ANSYS program.

  16. Silver buffer layers for YBCO thin films

    Energy Technology Data Exchange (ETDEWEB)

    Azoulay, J. [Tel Aviv Univ. (Israel). Center for Technol. Education Holon

    1999-09-01

    A simple economical conventional vacuum system was used for evaporation of YBCO thin films on as-deposited unbuffered Ag layers on MgO substrates. The subsequent heat treatment was carried out in low oxygen partial pressure at a relative low temperature and short dwelling time. The films thus obtained were characterized for electrical properties using dc four probe electrical measurements and inspected for structural properties and chemical composition by scanning electron microscopy (SEM). (orig.)

  17. Photoluminescence Study of Copper Selenide Thin Films

    Science.gov (United States)

    Urmila, K. S.; Asokan, T. Namitha; Pradeep, B.

    2011-10-01

    Thin films of Copper Selenide of composition of composition Cu7Se4 with thickness 350 nm are deposited on glass substrate at a temperature of 498 K±5 K and pressure of 10-5 mbar using reactive evaporation, a variant of Gunther's three temperature method with high purity Copper (99.999%) and Selenium (99.99%) as the elemental starting material. The deposited film is characterized structurally using X-ray Diffraction. The structural parameters such as lattice constant, particle size, dislocation density; number of crystallites per unit area and strain in the film are evaluated. Photoluminescence of the film is analyzed at room temperature using Fluoro Max-3 Spectrofluorometer.

  18. Biomimetic thin film synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Graff, G.L.; Campbell, A.A.; Gordon, N.R.

    1995-05-01

    The purpose of this program is to develop a new process for forming thin film coatings and to demonstrate that the biomimetic thin film technology developed at PNL is useful for industrial applications. In the biomimetic process, mineral deposition from aqueous solution is controlled by organic functional groups attached to the underlying substrate surface. The coatings process is simple, benign, inexpensive, energy efficient, and particularly suited for temperature sensitive substrate materials (such as polymers). In addition, biomimetic thin films can be deposited uniformly on complex shaped and porous substrates providing a unique capability over more traditional line-of-sight methods.

  19. Piezoresistive polymer composites for cantilever readout

    DEFF Research Database (Denmark)

    Lillemose, Michael

    concentrations. No signicant piezoresistive eect was observed for the silver nanoparticle doped composites. Thin lm structures of the intrinsically conductive polymer, polyaniline, have been fabricated and a negative piezoresistive eect was observed. Thin gold lms were investigated, with the aim of measuring...... thin lm can be strained, while measuring how the resistance changes. This allows the determination of the strain sensitivity of the materials. Three qualitatively dierent material types have been investigated: conductive polymer composites, an intrinsically conductive polymer and thin gold lms....... Conducting polymer composites consisting of SU-8 (an epoxy based photoresist) and dierent concentrations of carbon- and silver nanoparticles have been investigated. For the carbon nanoparticle doped SU-8 composites, a positive piezoresistive eect was measured, with the largest eect towards the lower...

  20. Preparation and optical and electrical evaluation of bulk SiO{sub 2} sonogel hybrid composites and vacuum thermal evaporated thin films prepared from molecular materials derived from (Fe, Co) metallic phthalocyanines and 1,8 dihydroxiantraquinone compounds

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Vergara, Maria Elena [Coordinacion de Ingenieria Mecatronica, Facultad de Ingenieria, Universidad Anahuac Mexico Norte. Avenida Universidad Anahuac 46, Col. Lomas Anahuac, 52786 Huixquilucan, Estado de Mexico (Mexico); Morales-Saavedra, Omar G. [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico)], E-mail: omar.morales@ccadet.unam.mx; Ontiveros-Barrera, Fernando G.; Torres-Zuniga, Vicente; Ortega-Martinez, Roberto [Universidad Nacional Autonoma de Mexico, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, CCADET-UNAM, A.P. 70-186, Coyoacan, 04510 Mexico, D.F. (Mexico); Ortiz Rebollo, Armando [Universidad Nacional Autonoma de Mexico, Instituto de Investigaciones en Materiales, IIM-UNAM, A.P. 70-360, Coyoacan, 04510 Mexico, D.F. (Mexico)

    2009-02-25

    Semiconducting molecular material of PcFe(CN)L1 and PcCo(CN)L1 (L1 = 1,8 dihydroxianthraquinone), PcFe(CN)L2 and PcCo(CN)L2 (L2 = double potassium salt of 1,8 dihydroxianthraquinone) have been successfully used to prepare thin film and bulk sol-gel hybrid optical materials. These samples were developed according to the vacuum thermal evaporation technique and the catalyst-free sonogel route, respectively. Thin films samples were deposited on Corning glass substrates and crystalline silicon wafers and were characterized by infrared (FTIR), Raman and ultraviolet-visible (UV-vis) spectroscopies. IR-spectroscopy and Raman studies unambiguously confirmed that the molecular material thin films exhibit the same intra-molecular bonds, which suggests that the thermal evaporation process does not alter these bonds significantly. These results show that it is possible to deposit molecular materials of PcFe(CN)L2 and PcCo(CN)L2 on Corning glass substrates and silicon wafers. From the UV-vis studies the optical band gap (E{sub g}) was evaluated. The effect of temperature on conductivity was also evaluated in these samples. Finally, the studied molecular systems dissolved at different concentrations in tetrahydrofuran (THF) were successfully embedded into a highly pure SiO{sub 2} sonogel network generated via sonochemical reactions to form several solid state, optically active sol-gel hybrid glasses. By this method, homogeneous and stable hybrid monoliths suitable for optical characterization can be produced. The linear optical properties of these amorphous bulk structures were determined by the Brewster angle method and by absorption-, Raman- and photoluminescent (PL)-spectroscopies, respectively.

  1. TEC – Thin Environmental Cladding

    Directory of Open Access Journals (Sweden)

    Alan Tomasi

    2015-05-01

    Full Text Available Permasteelisa Group developed with Fiberline Composites a new curtain wall system (Thin Environmental Cladding or TEC, making use of pultruded GFRP (Glass Fiber Reinforced Polymer material instead of traditional aluminum. Main advantages using GFRP instead of aluminum are the increased thermal performance and the limited environmental impact. Selling point of the selected GFRP resin is the light transmission, which results in pultruded profiles that allow the visible light to pass through them, creating great aesthetical effects. However, GFRP components present also weaknesses, such as high acoustic transmittance (due to the reduced weight and anisotropy of the material, low stiffness if compared with aluminum (resulting in higher facade deflection and sensible fire behavior (as combustible material. This paper will describe the design of the TEC-facade, highlighting the functional role of glass within the facade concept with regards to its acoustic, structural, aesthetics and fire behavior.

  2. Thin film device applications

    CERN Document Server

    Kaur, Inderjeet

    1983-01-01

    Two-dimensional materials created ab initio by the process of condensation of atoms, molecules, or ions, called thin films, have unique properties significantly different from the corresponding bulk materials as a result of their physical dimensions, geometry, nonequilibrium microstructure, and metallurgy. Further, these characteristic features of thin films can be drasti­ cally modified and tailored to obtain the desired and required physical characteristics. These features form the basis of development of a host of extraordinary active and passive thin film device applications in the last two decades. On the one extreme, these applications are in the submicron dimensions in such areas as very large scale integration (VLSI), Josephson junction quantum interference devices, magnetic bubbles, and integrated optics. On the other extreme, lar