Science.gov

Sample records for 3-glycidoxypropyltrimethoxysilane films studied

  1. Grafting of organosilane derived from 3-glycidoxypropyltrimethoxysilane and thiourea onto magnesium phyllosilicate by sol-gel process and investigation of metal adsorption properties

    SciTech Connect

    Dey, R.K.; Oliveira, Andrea S.; Patnaik, Tanushree; Singh, V.K.; Tiwary, D.; Airoldi, Claudio

    2009-08-15

    A layered inorganic-organic magnesium silicate (Mg-GTPS-TU) has been successfully synthesized by using sol-gel based precursor under mild temperature conditions and a new silylaing agent (GTPS-TU) derived from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. The hybrid material was characterized through elemental analysis, infrared spectroscopy, X-ray diffractometry, thermogravimetry, and carbon and silicon solid-state nuclear magnetic resonance spectroscopy. The result confirmed the attachment of organic functionality to the inorganic silicon network. The inter-lamellar distance for the hybrid material was found to be 18.8 A. Metal adsorption characteristics follows Cr(III) >Mn(II)>Zn(II) with more affinity towards Cr(III) in dilute aqueous solution. Evaluation of thermodynamic parameters DELTAH and DELTAS for Cr(III) were found to be 25.44 J mol{sup -1} and 79.9 J mol{sup -1} K{sup -1}, respectively, indicating adsorption process to be endothermic in nature. The negative value of DELTAG indicated the feasibility and spontaneity of ongoing adsorption process at relatively higher temperature. The presence of multiple coordination sites in the attached organic functionality expresses the potentiality of the hybrid material containing new silylating agent for heavy cation removal from eco-system. - Abstract: We report the synthesis and adsorption properties of a layered inorganic-organic magnesium silicate (Mg-GTPS-TU) derived from a new silylaing agent from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. Display Omitted

  2. Grafting of organosilane derived from 3-glycidoxypropyltrimethoxysilane and thiourea onto magnesium phyllosilicate by sol-gel process and investigation of metal adsorption properties

    NASA Astrophysics Data System (ADS)

    Dey, R. K.; Oliveira, Andrea S.; Patnaik, Tanushree; Singh, V. K.; Tiwary, D.; Airoldi, Claudio

    2009-08-01

    A layered inorganic-organic magnesium silicate (Mg-GTPS-TU) has been successfully synthesized by using sol-gel based precursor under mild temperature conditions and a new silylaing agent (GTPS-TU) derived from 3-glycidoxypropyltrimethoxysilane (GTPS) and thiourea (TU) as the silicon source. The hybrid material was characterized through elemental analysis, infrared spectroscopy, X-ray diffractometry, thermogravimetry, and carbon and silicon solid-state nuclear magnetic resonance spectroscopy. The result confirmed the attachment of organic functionality to the inorganic silicon network. The inter-lamellar distance for the hybrid material was found to be 18.8 Å. Metal adsorption characteristics follows Cr(III) >Mn(II)>Zn(II) with more affinity towards Cr(III) in dilute aqueous solution. Evaluation of thermodynamic parameters ΔH and ΔS for Cr(III) were found to be 25.44 J mol -1 and 79.9 J mol -1 K -1, respectively, indicating adsorption process to be endothermic in nature. The negative value of Δ G indicated the feasibility and spontaneity of ongoing adsorption process at relatively higher temperature. The presence of multiple coordination sites in the attached organic functionality expresses the potentiality of the hybrid material containing new silylating agent for heavy cation removal from eco-system.

  3. Contemporary Films' Mini Course on Film Study.

    ERIC Educational Resources Information Center

    Schillaci, Peter

    This minicourse on film study can be a unit in English, in arts, or in the humanities. It can help to launch a film study course or complement an introduction to theater. Whatever form it takes, it helps to build a bridge to the student's media environment. Part one, the language of images, utilizes four films which demonstrate the basic elements…

  4. Film Study in Higher Education.

    ERIC Educational Resources Information Center

    Stewart, David C., Ed.

    This resource book on the place of film study today is designed to assist in the planning of college courses in the history, criticism, and appreciation of motion pictures. Representative course descriptions and appraisals are given by (1) Jack C. Ellis, who describes a two-part course in film aesthetics and types of films, (2) Edward Fischer, who…

  5. Center for thin film studies

    NASA Astrophysics Data System (ADS)

    Shannon, Robert P.; Gibson, Ursula J.

    1987-11-01

    This report covers the first year of operation of the URI Thin Film Center (TFC), and describes a diverse array of studies on thin-film materials, substrates, and their processing and analysis. Individual efforts are highlighted in sections on nucleation studies, ion-assisted deposition, Rutherford backscattering spectrometry, Brillouin scattering, a continuum theory of the evolution of structure in thin films, a study of polishing parameters relevant to the preparation of substrates, and the setup of a characterization facility for the Center.

  6. Film Study Hang Ups.

    ERIC Educational Resources Information Center

    Grenier, Charles F.

    1969-01-01

    The interest and delight which students find in film should be preserved from a teacher's excessive zeal to analyze and explain. As the beauty of poetry is frequently diminished through exhaustive analyses of similes, rhyme schemes, and other technical devices, the value of film to high school students can be weakened through too great an emphasis…

  7. Film Study: A Resource Guide.

    ERIC Educational Resources Information Center

    Manchel, Frank

    This resource guide describes six popular approaches to the study of the cinema and provides a practical analysis of selected books, materials, and information about motion picture rentals. Highlighting this extensive survey of film studies are the annotated, critical bibliographies and filmographies of significant books, articles and films by and…

  8. Radical Voices; A Film Course Study Guide.

    ERIC Educational Resources Information Center

    Kernan, Margot

    The leftist radical ideas current in the 1960s and 1970s are expressed in the films discussed in this cinema study guide. The radical film takes extreme and avant-garde approaches to the somewhat publicly taboo topics of sex, social issues, and religion. Among the films discussed, I AM CURIOUS (YELLOW) and SOMETHING DIFFERENT show women in their…

  9. Study on aluminium-based single films.

    PubMed

    Vinod Kumar, G S; García-Moreno, F; Babcsán, N; Brothers, A H; Murty, B S; Banhart, J

    2007-12-28

    In the present paper the authors studied isolated metallic films made from the same material used for making metallic foams, and then characterised their properties. Metal films were made from a liquid aluminium alloy reinforced with ceramic particles of known concentration. Melts without such particles were also investigated. It is shown that stable films could not be made from Al-Si alloy having no particles, and just extremely thin and fragile films could be made from commercially-pure Al. In contrast, aluminium alloys containing particles such as SiC and TiB(2) allowed pulling thin, stable films, which did not rupture. Significant thinning of films was observed when the particle concentration in the melt decreased. By in situ X-ray monitoring of liquid films during pulling, film thickness and drainage effects within the liquid film could be studied. The morphology and microstructure of films was characterised after solidification. Our work shows that the question of how foams are stabilised can be studied using a simplified system such as a film, instead of having to deal with the multitude of different structural elements present in a foam. PMID:18060172

  10. Study of diamond film growth and properties

    NASA Technical Reports Server (NTRS)

    Albin, Sacharial

    1990-01-01

    The objective was to study diamond film growth and its properties in order to enhance the laser damage threshold of substrate materials. Calculations were performed to evaluate laser induced thermal stress parameter, R(sub T) of diamond. It is found that diamond has several orders of magnitude higher in value for R(sub T) compared to other materials. Thus, the laser induced damage threshold (LIDT) of diamond is much higher. Diamond films were grown using a microwave plasma enhanced chemical vapor deposition (MPECVD) system at various conditions of gas composition, pressure, temperature, and substrate materials. A 0.5 percent CH4 in H2 at 20 torr were ideal conditions for growing of high quality diamond films on substrates maintained at 900 C. The diamond films were polycrystalline which were characterized by scanning electron microscopy (SEM) and Raman scattering spectroscopy. The top surface of the growing film is always rough due to the facets of polycrystalline film while the back surface of the film replicates the substrate surface. An analytical model based on two dimensional periodic heat flow was developed to calculate the effective in-plane (face parallel) diffusivity of a two layer system. The effective diffusivity of diamond/silicon samples was measured using a laser pulse technique. The thermal conductivity of the films was measured to be 13.5 W/cm K, which is better than that of a type Ia natural diamond. Laser induced damage experiments were performed on bare Si substrates, diamond film coated Si, and diamond film windows. Significant improvements in the LIDT were obtained for diamond film coated Si compared to the bare Si.

  11. Study of iron mononitride thin films

    SciTech Connect

    Tayal, Akhil Gupta, Mukul Phase, D. M. Reddy, V. R. Gupta, Ajay

    2014-04-24

    In this work we have studied the crystal structural and local ordering of iron and nitrogen in iron mononitride thin films prepared using dc magnetron sputtering at sputtering power of 100W and 500W. The films were sputtered using pure nitrogen to enhance the reactivity of nitrogen with iron. The x-ray diffraction (XRD), conversion electron Mössbauer spectroscopy (CEMS) and soft x-ray absorption spectroscopy (SXAS) studies shows that the film crystallizes in ZnS-type crystal structure.

  12. Radiochromic dye film studies for brachytherapy applications.

    PubMed

    Martínez-Dávalos, A; Rodríguez-Villafuerte, M; Díaz-Perches, R; Arzamendi-Pérez, S

    2002-01-01

    Commercial radiochromic dye films have been used in recent years to quantify absorbed dose in several medical applications. In this study we present the characterisation of the GafChromic MD-55-2 dye film, a double sensitive layer film suitable for photon irradiation in brachytherapy applications. Dose measurements were carried out with a low dose rate 137Cs brachytherapy source, which produces very steep dose gradients in its vicinity, and therefore requires the capability of producing high spatial resolution isodose curves. Quantification of the dose rate in water per unit air kerma strength was obtained using a high-resolution transmission commercial scanner (Agfa DuoScan T1200 with the capability of digitising up to 600 x 1200 pixels per inch using 36 bits per pixel, together with optical density measurements. The Monte Carlo calculations and experimental measurements compared well in the 0-50 Gy dose interval used in this study. PMID:12382798

  13. Study of Fe-Co Nanocomposite Films

    SciTech Connect

    Lancok, A.; Klementova, M.; Kohout, J.; Miglierini, M.; Fendrych, F.; Lancok, J.

    2010-07-13

    Moessbauer study of nanogranular ferromagnetic FeCo films is presented. Two ways of production of nanocomposite systems were employed: (i) hollow cathode plasma jet deposition process, and (ii) laser ablation from Fe-Co metallic targets by means of a KrF excimer laser and r.f. magnetron sputtering. Complementary information on the composition of the samples were obtained by nuclear magnetic resonance of {sup 57}Fe and {sup 59}Co nuclei, conversion electron Moessbauer spectroscopy, and high resolution transmission electron microscopy. The films contain crystalline nanoparticles, 5-20 nm in size, embedded in an amorphous matrix.

  14. Implementing the Study of Multicultural Aesthetics in Film and Video.

    ERIC Educational Resources Information Center

    Gutenko, Gregory

    Film and television in the western world are highly stylized and culturally specific products. A course on multicultural aesthetics in film and video should introduce the student to perceptual alternatives in film and television use. Some of these alternatives can be derived from three well-established areas of film/television study: the…

  15. Film as Revolutionary Weapon: A Pedagogical Analysis. Latin American Studies Program, Film Series No. 3.

    ERIC Educational Resources Information Center

    California Univ., Riverside. Latin American Studies Program.

    This paper describes a university course designed to examine the use of film as a revolutionary medium in Latin American countries. Objectives of the course were to illustrate the complexity of studying a film genre, develop an analytical framework for comparing revolutionary films, and encourage students to reach their own conclusions about the…

  16. Radiation resistance studies of amorphous silicon films

    NASA Technical Reports Server (NTRS)

    Payson, J. Scott; Woodyard, James R.

    1988-01-01

    A study of hydrogenated amorphous silicon thin films irradiated with 2.00 MeV helium ions using fluences ranging from 1E11 to 1E15/sq cm is presented. The films were characterized using photothermal deflection spectroscopy, transmission and reflection spectroscopy, and photoconductivity and annealing measurements. Large changes were observed in the subband-gap optical absorption for energies between 0.9 and 1.7 eV. The steady-state photoconductivity showed decreases of almost five orders of magnitude for a fluence of 1E15/sq cm, but the slope of the intensity dependence of the photoconductivity remained almost constant for all fluences. Substantial annealing occurs even at room temperature, and for temperatures greater than 448 K the damage is completely annealed. The data are analyzed to describe the defects and the density of states function.

  17. Recent Developments in the Rhetorical Study of Film and Television.

    ERIC Educational Resources Information Center

    Benson, Tom

    Rhetorical studies of film and television arose more or less independently at a number of universities during the 1960s and 1970s. At Cornell University (New York), the accident of a combined speech and drama department gave rise to the study of the rhetoric of film. At the same time, other theorists were approaching film rhetoric from literature.…

  18. Reel Teaching = Real Learning: Motivating Reluctant Students through Film Studies

    ERIC Educational Resources Information Center

    Smilanich, Brad; Lafreniere, Nicole

    2010-01-01

    The authors provide a rationale for the critical study of film texts in the English language arts. For struggling or reluctant students, film offers an accessibility that the printed text may not. Students who are intimidated by, or impeded from, accessing print text are able to discuss film with acuity and insight. The study of visual texts can…

  19. Structural studies of ultrathin organic films

    NASA Astrophysics Data System (ADS)

    Yim, Hyun

    1998-11-01

    Ultrathin organic films have been a focus of research due to the growing interest in optoelectronics and molecular electronics. In both areas, it is believed that self-assembled (SA) films and Langmuir-Blodgett (LB) films may provide the desired control of order at the molecular level. The tethering of polyglutamate molecules to surfaces is of special interest due to nonlinear optical properties which can be achieved when the molecules are oriented. The tethering of poly(benzyl-L-glutamate) to silicon has been done by polymerization of benzyl-L-glutamate-N-carboxyanhydride using self-assembled monolayers with various concentrations of amino end groups as initiating layers. X-ray reflectivity results show that a minimum concentration of initiator sites on the surface is required. The second tethering system is a polystyrene brush. The polystyrene brush is expected to give strong sensitivity to solvent swelling. The structure of the polystyrene brush, which was chemically grafted to a substrate, in poor solvent and its change at different temperatures were investigated by neutron reflectometry. When temperature increases up to 30sp°C, both the thickness and roughness increase greatly, which indicates that the polystyrene brush changes from a collapsed state to a theta state. Hairy-rod polyimide molecules are of interest due to their interesting physical properties. Multilayer films of preformed polyimide molecules (6FDA-C18) have been obtained for the first time by the LB technique. The multilayer films do not display a distinctively periodic structure. Upon annealing for a few hours at 180sp°C, the structure relaxes slightly. The alkyl side chain substituted polyimides (BACBF/BPDA) can form metastable monolayers for which the pressure-area isotherms vary markedly with side chain length. For the polyimide with octadecyl side chains, a sharp reduction in zero pressure area occurs between 20 and 24sp°C, suggesting an important change in side chain mobility

  20. Polyethylene terephthalate thin films; a luminescence study

    NASA Astrophysics Data System (ADS)

    Carmona-Téllez, S.; Alarcón-Flores, G.; Meza-Rocha, A.; Zaleta-Alejandre, E.; Aguilar-Futis, M.; Murrieta S, H.; Falcony, C.

    2015-04-01

    Polyethylene Terephthalate (PET) films doped with Rare Earths (RE3+) have been deposited on glass by spray pyrolysis technique at 240 °C, using recycled PET and (RE3+) chlorides as precursors. Cerium, terbium, dysprosium and europium were used as dopants materials, these dopants normally produce luminescent emissions at 450, 545, 573 and 612 nm respectively; the doped films also have light emissions at blue, green, yellow and red respectively. All RE3+ characteristic emissions were observed at naked eyes. Every deposited films show a high transmission in the visible range (close 80% T), films surfaces are pretty soft and homogeneous. Films thickness is around 3 μm.

  1. Dynamic Metabolism Studies of Live Bacterial Films

    SciTech Connect

    Majors, Paul D.; Mclean, Jeffrey S.

    2008-11-01

    Bacterial film (biofilm) microbes exist within spatial (nutrient, electron-acceptor, pH, etc.) gradients of their own making. Correspondingly, biofilm bacteria are physiologically and functionally distinct from free-floating bacteria and from their own species at differing biofilm depths. This article describes our efforts to develop noninvasive nuclear magnetic resonance (NMR) technologies for biofilm-metabolism studies. This involves integrating NMR with controlled-cultivation methods to interrogate microbial physiology live and under known growth conditions. NMR is uniquely capable of providing depth-resolved metabolic and transport information in a non-invasive, non-sample-consuming fashion, providing information required for experimental reactive transport studies. We have studied mono-species biofilms relevant to environment remediation and human health. We describe these technologies, discuss their advantages and limitations, and give examples of their application.

  2. Experimental study of drop impacts on soap films

    NASA Astrophysics Data System (ADS)

    Yawar, Ali; Basu, Saikat; Concha, Andres; Bandi, Mahesh

    2015-11-01

    Impinging drops on flowing and static soap films demonstrate at least three distinct types of impact regimes: (a) the drop bounces off the film surface, (b) it coalesces with the downstream flow for a moving film and for static films it gets assimilated within the film, and (c) it pierces through the film. The interaction presents a unique opportunity to explore the impact of a quasi one-dimensional object on a two-dimensional fluid, much like a comet impacting on a thin atmosphere. We present a detailed experimental study of droplet impacts on soap film flow, for a number of film inclination angles and falling heights of the drop. Imaging techniques employed include sodium lamp interferometry to measure film thickness fluctuations and particle tracking velocimetry to measure the velocity field. Film thickness measures approximately 10 microns and the drop diameter is 1 mm. We mostly observe the bouncing-off regime for smaller inclination angles. However, at higher impact angles, puncturing of the film becomes a more common occurrence. We show that when the drop bounces off the film, there is a momentum transfer leading to vortex dipole shedding, along with the generation of capillary waves; an impulsive regime that may share correspondence with the locomotion of water striders.

  3. Thin teflon-like films for MEMS: Film properties and reliability studies

    SciTech Connect

    Smith, B.K.; LaVigne, G.; Sniegowski, J.J.; Brown, C.D.

    1998-07-01

    This work presents film properties and initial reliability studies for thin Teflon-like films applied to a unique test vehicle, the Sandia-designed and fabricated microengine. Results on microengines coated with the film show a factor of three improvement in their lifetime and an order of magnitude reduction in the coefficient of friction when compared to uncoated samples. Coefficients Of Friction (COF) of 0.07 for the Teflon-like film and 1.0 for uncoated samples are extracted from models which match the measured behavior of working microengines. These films, deposited form a plasma source, exhibit the ability to penetrate into very narrow, deep channels common to many MEMS devices. For as-deposited film, both the refractive index at 1.4 and the contact angle with water at 108{degree} show the film to be very similar to bulk Teflon PTFE. Film stability as a function of temperature has been examined using Fourier Transformation Infrared (FTIR) spectroscopy. The film structure as observed by the fluorine-carbon (F-C) peak is stable up to 200 C, but starts decomposing above 250 C. Film composition has been examined using X-ray photoelectron spectroscopy (XPS) and is quite different for directly exposed surfaces compared with deep, narrow channels where the deposition process is diffusion limited.

  4. Micromagnetic studies of thin metallic films (invited)

    NASA Astrophysics Data System (ADS)

    Zhu, Jian-Gang; Bertram, H. Neal

    1988-04-01

    A computer simulation model has been developed to conduct micromagnetic studies of thin magnetic films. Thin-film media are modeled as a planar hexagonal array of hexagonally shaped grains. Each grain is a single domain particle whose magnetization reverses by coherent rotation. The computation utilizes coupled gyromagnetic dynamic equations with phenomenological Landau-Lifshitz damping. In particular, the effects of particle interactions are investigated. The effect of media microstructure on magnetic hysteresis is examined as well as the effect of intergranular exchange coupling. The difference between planar and completely random orientation of the crystalline anisotropy axes is discussed. Recorded transitions are simulated by allowing a pair of perfect transitions to relax. With no intergranular exchange coupling, the transitions show profound irregularity and zig-zag structure. Intergranular exchange coupling produces more uniform transitions with increased zig-zag structure amplitude. For a closely spaced transition pair, the equilibrium configuration yields percolated transition boundaries with stable reverse island domains. The effect of gyromagnetic precession also has been examined.

  5. Studies of Niobium Thin Film Produced by Energetic Vacuum Deposition

    SciTech Connect

    Genfa Wu; Anne-Marie Valente; H. Phillips; Haipeng Wang; Andy Wu; T. J. Renk; P Provencio

    2004-05-01

    An energetic vacuum deposition system has been used to study deposition energy effects on the properties of niobium thin films on copper and sapphire substrates. The absence of working gas avoids the gaseous inclusions commonly seen with sputtering deposition. A biased substrate holder controls the deposition energy. Transition temperature and residual resistivity ratio of the niobium thin films at several deposition energies are obtained together with surface morphology and crystal orientation measurements by AFM inspection, XRD and TEM analysis. The results show that niobium thin films on sapphire substrate exhibit the best cryogenic properties at deposition energy around 123 eV. The TEM analysis revealed that epitaxial growth of film was evident when deposition energy reaches 163 eV for sapphire substrate. Similarly, niobium thin film on copper substrate shows that film grows more oriented with higher deposition energy and grain size reaches the scale of the film thickness at the deposition energy around 153 eV.

  6. Educational Film Guide for Middle Eastern Studies.

    ERIC Educational Resources Information Center

    Greenman, Joseph; Joachim, Ann

    This annotated guide lists 16mm. films on the Middle East for use in grades K-12 and with adults. The Middle East refers to a vast area extending from eastern Afghanistan and the northern Caucasus to the western coast of Morocco and the southern periphery of the Sahara. The guide does not list films according to their merits. Rather, it includes…

  7. New Water Vapor Barrier Film Based on Lamellar Aliphatic-Monoamine-Bridged Polysilsesquioxane.

    PubMed

    Zhang, Cong; Zhang, Ce; Ding, Ruimin; Cui, Xinmin; Wang, Jing; Zhang, Qinghua; Xu, Yao

    2016-06-15

    Siloxane-based hybrid lamellar materials with ordered nanostructure units paralleling to the substrate have been widely used for water vapor barrier. However, it is very difficult to control the orientation of the lamellar units at molecular level. In this Research Article, a new lamellar bridged polysilsesquioxane (BPSQ) film, whose voids between lamellae were filled by pendant alkyl chains in the organic bridge, was prepared via the stoichiometric reaction between 3-glycidoxypropyltrimethoxysilane and aliphatic monoamine at 60 °C without catalyst. Experimental evidence obtained from FT-IR, MS, NMR, and GIXRD techniques suggested that the as-prepared BPSQ films were constructed by lamellar units with disordered orientation. Nonetheless, they possessed satisfactory water vapor barrier performance for potassium dihydrogen phosphate (KDP) and deuterated potassium dihydrogen phosphate (DKDP) optical crystals, and the water vapor transmission rate through BPSQ film with thickness of 25 μm was as low as 20.3 g·m(-2)·d(-1). Those results proved that filling the voids between molecular lamellae with alkyl chains greatly weakened the effect of lamellar unit orientation on the vapor barrier property of BPSQ film. PMID:27224032

  8. Structural and Other Studies of Langmuir-Blodgett Films.

    NASA Astrophysics Data System (ADS)

    Prakash, Maneesha

    Certain organic materials comprised of ampiphilic molecules will spread on the surface of water to form monolayer films known as Langmuir films. These films can be transferred to solid substrates by dipping the substrates in and out of the water. The films transfer to the substrates monolayer by monolayer and the resulting built-up films are known as Langmuir-Blodgett films. Langmuir-Blodgett films are very regular, with the planes aligned parallel to a high degree. This technique has potential for building structures that may exhibit unusual mechanical, optical, magnetic or electronic properties. Because the proposed uses of Langmuir-Blodgett films depend in a fundamental way on their structure, structural studies of Langmuir-Blodgett films are of great relevance. We have made Langmuir and Langmuir-Blodgett films of simple materials for the purpose of x-ray diffraction characterization. We have looked for differences between the structure of the materials in bulk form as compared with the structure in Langmuir -Blodgett film form. We have studied the in-plane structure of films of the lead salts of various fatty acids using both an external reflection geometry for samples made on glass slide substrates, and a transmission geometry for samples made on thin single crystal mica substrates. Information concerning the in-plane structure and correlations between the layers has been obtained. For the samples made on single crystal mica substrates, epitaxial growth has been observed, whereas on glass substrates the samples have been found to be powders in the plane. An anomalous intensity pattern has been observed for the in-plane and out-of-the -plane peaks. We have proposed a positioning of the hydrocarbon chans that nicely explains the data. We have investigated the conditions for transfer of films on the lipid dipalmitoylphosphatidylcholine, a primary consituent of cell membranes. We have succeeded in forming Langmuir-Blodgett films of this material by the addition of

  9. Reading in the Social Studies: Using Subtitled Films

    ERIC Educational Resources Information Center

    Holmes, Kerry; Russell, William B., III; Movitz, Allison

    2007-01-01

    Involving reluctant and low-achieving students with reading is an essential step to increasing students' content area knowledge. One way to increase students' engagement with text is by linking social studies content with foreign films that have English subtitles. Not only can subtitled films help increase students' engaged time with text, but the…

  10. Drying of polymer films: study of demixing phenomena

    NASA Astrophysics Data System (ADS)

    Fichot, Julie; Heyd, Rodolphe; Saboungi, Marie-Louise; Josserend, Christophe; Combard, Emilie; Tranchant, Jean Francois

    2011-03-01

    Understanding the mechanisms that control the stability of polymeric films is important in beauty care. We have prepared films starting from a water-soluble organic polymer, a preservative and water. We study the drying of these films as a function of several physicochemical parameters that control their interfaces such as temperature, humidity and the nature of the support. The viscoelastic properties of the solutions before spreading out are analyzed with a rheometer in order to adjust the temperature. The topography of the films is observed by optical microscopy and the evolution of the drying is determined with a precision gravimetric balance. The behavior of the films on a nanometric scale is followed by AFM. During the drying process, droplets appear on the surface of the film, made up of water surrounded by a shell of preservative. As the films dries, the water evaporates from the droplets and the preservative spreads on the surface of the film, leading to the formation of craters on the surface of the dried film. The dimensions and numbers of the craters depend strongly on the type and concentration of the preservative employed.

  11. Radiation resistance studies of amorphous silicon films

    NASA Technical Reports Server (NTRS)

    Woodyard, James R.; Payson, J. Scott

    1989-01-01

    Hydrogenated amorphous silicon thin films were irradiated with 2.00 MeV helium ions using fluences ranging from 1E11 to 1E15 cm(-2). The films were characterized using photothermal deflection spectroscopy and photoconductivity measurements. The investigations show that the radiation introduces sub-band-gap states 1.35 eV below the conduction band and the states increase supralinearly with fluence. Photoconductivity measurements suggest the density of states above the Fermi energy is not changing drastically with fluence.

  12. Feasibility Study of Thin Film Thermocouple Piles

    NASA Technical Reports Server (NTRS)

    Sisk, R. C.

    2001-01-01

    Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

  13. Cratering Studies in Thin Plastic Films

    NASA Astrophysics Data System (ADS)

    Shu, A. J.; Bugiel, S.; Gruen, E.; Hillier, J. K.; Horanyi, M.; Munsat, T.

    2012-12-01

    Thin plastic films, such as Polyvinylidene Fluoride (PVDF), have been used as protective coatings or dust detectors on a number of missions including the Dust Counter and Mass Analyzer (DUCMA) instrument on Vega 1 and 2, the High Rate Detector (HRD) on the Cassini Mission, and the Student Dust Counter (SDC) on New Horizons. These types of detectors can be used on the lunar surface or in lunar orbit to detect dust grain size distributions and velocities. Due to their low power requirements and light weight, large surface area detectors can be built for observing low dust fluxes. The SDC dust detector is made up of a permanently polarized layer of PVDF coated on both sides with a thin layer (≈ 100 nm) of aluminum nickel. The operation principle behind this type of detector is that a micrometeorite impact removes a portion of the metal surface layer exposing the permanently polarized PVDF underneath. This causes a local potential near the crater changing the surface charge of the metal layer. The dimensions of the crater determine the strength of the potential and thus the signal generated by the PVDF. The theory uses a crater diameter scaling law which was not intended for use with PVDF. Work is being undertaken to develop a new crater diameter scaling law using iron particles in 52 μm thick PVDF. Samples were brought to the Heidelberg Dust Accelerator and exposed to a selected range of mass and velocities. Samples are being analyzed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS) using 3D reconstruction photogrammetry using stereo pairs taken in a scanning electron microscope (SEM) and cross sections taken in a focused ion beam (FIB). Further work is planned at the CCLDAS dust accelerator.

  14. Structural study of Ge/GaAs thin films

    NASA Astrophysics Data System (ADS)

    Lazarov, V. K.; Lari, L.; Lytvyn, P. M.; Kholevchuk, V. V.; Mitin, V. F.

    2012-07-01

    Ge/GaAs heterostructure research is largely motivated by the application of this material in solar cells, metal-oxide-semiconductor field-effect transistors, mm-wave mixer diodes, temperature sensors and photodetectors. Therefore, understanding of how the properties of Ge/GaAs heterostructure depend on its preparation (growth) is of importance for various high-efficiency devices. In this work, by using thermal Ge evaporation on GaAs(100), we studied structural properties of these films as a function of the deposition rate. Film grains size and morphology show strong dependence of the deposition rate. Low deposition rates results in films with large crystal grains and rough surface. At high deposition rates films become flatter and their crystal grains size decreases, while at very high deposition rates films become amorphous. Cross-sectional TEM of the films show that the Ge films are granular single crystal epitaxially grown on GaAs. The Ge/GaAs interface is atomically abrupt and free from misfit dislocations. Stacking faults along the [111] directions that originate at the interface were also observed. Finally by using the Kelvin probe microscopy we show that work function changes are related to the grain structure of the film.

  15. Spectroscopic studies of refractory and dielectric thin films

    SciTech Connect

    Truong, C.M.

    1993-01-01

    This work demonstrated the application of the techniques and methodology of surface science to investigate the mechanisms of thin film deposition processes on solid surfaces. The synthesis of boron nitride (BN) thin films was studied using X-ray photoelectron spectroscopy (XPS) and thermal desorption spectroscopy (TDS). In this model system, diborane (B[sub 2]H[sub 6]), ammonia (NH[sub 3]) and hydrazine (N[sub 2]H[sub 4]) were used as precursors to deposit BN thin films on a clean Ru(0001) surface. The result showed that ammonia reaction with diborane yielded only boron-rich boron nitride overlayers. However, stoichiometric BN films in excess of one monolayer could be produced when hydrazine was substituted for ammonia. The effects of oxygen on boron-rich and stoichiometric boron-nitrogen films were also examined. In the second part of this work, high resolution electron energy loss spectroscopy (HREELS) was used to characterize defect centers in MgO and in lithium-doped MgO thin films. The HREELS results showed that MgO thin films grown on Mo(100) were nearly defect-free at temperatures up to 1100 K. HREELS measurements indicated that annealings to higher temperatures induced F-type defect centers in the MgO films. The formation of [Li[sup +]O[sup [minus

  16. Integrating Asian Film into Film Studies and Film Production Courses Using Examples from Yasujiro Ozu (Japan) and Zhang Yimou (China). Asian Studies Module, 1997.

    ERIC Educational Resources Information Center

    Carson, Diane

    This curriculum module offers concrete and specific examples for instructors who wish to integrate the films of Yasujiro Ozu of Japan and Zhang Yimou from China into film studies courses. Through this module, students should learn to compare and contrast conventional screen space, color, and editing to alternative forms. By becoming more familiar…

  17. Study of Langmuir and Langmuir-Blodgett Thin films

    NASA Astrophysics Data System (ADS)

    Goodwin, Ross; Prayaga, Chandra; Wade, Aaron

    Arachidic Acid, Cholesterol, and Stearic Acid thin films were created and studied utilizing the Langmuir method in order to obtain a single molecule or monomolecular layer out of a desired substance at an air-water interface. The phase transitions are observed by measuring the surface pressure vs. area isotherms. Langmuir-Blodgett (LB) films were created on a prepared substrate. The LB film structures were then studied using X-ray Diffraction, and Raman Spectroscopy. UWF Office of Undergraduate Research Project Award, UWF ITEP-Technology Fee Project Award, UWF Quality Enhancement Plan Award.

  18. A thin film hydroponic system for plant studies

    NASA Technical Reports Server (NTRS)

    Hines, Robert; Prince, Ralph; Muller, Eldon; Schuerger, Andrew

    1990-01-01

    The Land Pavillion, EPCOT Center, houses a hydroponic, thin film growing system identical to that residing in NASA's Biomass Production Chamber at Kennedy Space Center. The system is targeted for plant disease and nutrition studies. The system is described.

  19. Film Balance Studies of Membrane Lipids and Related Molecules

    ERIC Educational Resources Information Center

    Cadenhead, D. A.

    1972-01-01

    Discusses apparatus, techniques, and measurements used to determine cell membrane composition. The use of a film balance to study monolayer membranes of selected lipids is described and results reported. (TS)

  20. Study of the photovoltaic effect in thin film barium titanate

    NASA Technical Reports Server (NTRS)

    Grannemann, W. W.; Dharmadhikari, V. S.

    1982-01-01

    Ferroelectric films of barium titanate were synthesized on silicon and quartz substrates, and the photoelectric effect in the structure consisting of metal deposited ferroelectric barium titanate film silicon was studied. A photovoltage with polarity that depends on the direction of the remanent polarization was observed. The deposition of BaTiO3 on silicon and fused quartz substrates was accomplished by an rf sputtering technique. A series of experiments to study the growth of ferroelectric BaTiO3 films on single crystal silicon and fused quartz substrates were conducted. The ferroelectric character in these films was found on the basis of evidence from the polarization electric field hysteresis loops, capacitance voltage and capacitance temperature techniques and from X-ray diffraction studies.

  1. Cryogenic Fluid Film Bearing Tester Development Study

    NASA Technical Reports Server (NTRS)

    Scharrer, Joseph K. (Editor); Murphy, Brian T.; Hawkins, Lawrence A.

    1993-01-01

    Conceptual designs were developed for the determination of rotordynamic coefficients of cryogenic fluid film bearings. The designs encompassed the use of magnetic and conventional excitation sources as well as the use of magnetic bearings as support bearings. Test article configurations reviewed included overhung, floating housing, and fixed housing. Uncertainty and forced response analyses were performed to assess quality of data and suitability of each for testing a variety of fluid film bearing designs. Development cost and schedule estimates were developed for each design. Facility requirements were reviewed and compared with existing MSFC capability. The recommended configuration consisted of a fixed test article housing centrally located between two magnetic bearings. The magnetic bearings would also serve as the excitation source.

  2. Before You Kill the Lights: A Practical Guide to Setting Up a Film Study Program.

    ERIC Educational Resources Information Center

    Greiner, Charles F.

    1979-01-01

    Offers suggestions on how to make a film study course challenging and enjoyable, through using a variety of films, defining visual literacy, choosing films with cinematic and literary value, and deciding on a specific approach for the course. (FL)

  3. Experimental study of uncentralized squeeze film dampers

    NASA Technical Reports Server (NTRS)

    Quinn, R. D.

    1983-01-01

    The vibration response of a rotor system supported by a squeeze film damper (SFD) was experimentally investigated in order to provide experimental data in support of the Rotor/Stator Interactive Finite Element theoretical development. Part of the investigation required the designing and building of a rotor/SFD system that could operate with or without end seals in order to accommodate different SFD lengths. SFD variables investigated included clearance, eccentricity mass, fluid pressure, and viscosity and temperature. The results show inlet pressure, viscosity and clearance have significant influence on the damper performance and accompanying rotor response.

  4. Experimental study of heat transfer to falling liquid films

    NASA Astrophysics Data System (ADS)

    Fagerholm, N. E.; Kivioja, K.; Ghazanfari, A. R.; Jaervinen, E.

    1985-12-01

    This project was initiated in order to obtain more knowledge about thermal design of falling film heat exchangers and to find methods to improve heat transfer in film flow. A short literature survey of film flow characteristics and heat transfer is presented. An experimental apparatus designed and built for studying falling film evaporation is described. The first experiments were made with smooth Cu tube 25/22 mm and refrigerant R114 as evaporating liquid. A significant amount of droplet entrainment was observed during the tests. The measured average heat transfer coefficient varied from 1000 to 1800 W/m K when Re=1300 to 11000 respectively and when the transfer mode is surface evaporation. This could be predicted accurately with the experimental correlation of Chun and Seban. When nucleate boiling is dominant the heat transfer could be predicted well with pool boiling correlation of VDI-84.

  5. Scanning tunneling microscopy studies of diamond films and optoelectronic materials

    NASA Technical Reports Server (NTRS)

    Perez, Jose M.

    1993-01-01

    In this report, we report on progress achieved from 12/1/92 to 10/1/93 under the grant entitled 'Scanning Tunneling Microscopy Studies of Diamond Films and Optoelectronic Materials'. We have set-up a chemical vapor deposition (CVD) diamond film growth system and a Raman spectroscopy system to study the nucleation and growth of diamond films with atomic resolution using scanning tunneling microscopy (STM). A unique feature of the diamond film growth system is that diamond films can be transferred directly to the ultrahigh vacuum (UHV) chamber of a scanning tunneling microscope without contaminating the films by exposure to air. The University of North Texas (UNT) provided $20,000 this year as matching funds for the NASA grant to purchase the diamond growth system. In addition, UNT provided a Coherent Innova 90S Argon ion laser, a Spex 1404 double spectrometer, and a Newport optical table costing $90,000 to set-up the Raman spectroscopy system. The CVD diamond growth system and Raman spectroscopy system will be used to grow and characterize diamond films with atomic resolution using STM as described in our proposal. One full-time graduate student and one full-time undergraduate student are supported under this grant. In addition, several graduate and undergraduate students were supported during the summer to assist in setting-up the diamond growth and Raman spectroscopy systems. We have obtained research results concerning STM of the structural and electronic properties of CVD grown diamond films, and STM and scanning tunneling spectroscopy of carbon nanotubes. In collaboration with the transmission electron microscopy (TEM) group at UNT, we have also obtained results concerning the optoelectronic material siloxene. These results were published in refereed scientific journals, submitted for publication, and presented as invited and contributed talks at scientific conferences.

  6. Study of ordered macroporous polymer films by templating breath figures

    NASA Astrophysics Data System (ADS)

    Song, Lulu

    2005-11-01

    Macroporous films with highly ordered pore patterns have many potential applications. Some examples include microstructured electrode surfaces, photonic band gap materials and filters for cell sorting and bio-interfaces. In this dissertation we discuss a "moist-casting" method to prepare hexagonally-ordered macroporous films with pore sizes in the range of sub-micron to several microns, where condensed water droplets ("breath figures") work as templates. Compared with other templating methods, this one is fast and simple. Well-ordered porous films can be obtained in tens of seconds and the pore size can be easily tailored and dynamically controlled by adjusting the casting conditions. More importantly, there is no need to remove the templates; water droplets just evaporate when the casting processes are finished. This study was carried out with the intention of characterizing the structures, understanding film-formation processes and exploring special properties and possible applications. For the structural characterization, film morphology was studied in detail by normal optical microscopy and laser scanning confocal microscopy (LSCM). Several interesting features have been revealed. Meanwhile, the degree of the order of the porous structures were characterized both in real space via Voronoi diagram and bond-orientational correlation function, and in reciprocal space via Fraunhofer diffraction pattern. To further understand the mechanism, the evaporation of the polymer solutions during the film formation was studied by monitoring their mass over time. Besides, the evolution of breath figures formed on the evaporating polymer solutions was in-situ recorded via a high-speed camera coupled to an optical microscope. Combined with the information on the film structures obtained via LSCM, explanations for some detailed features have been attempted. Wetting property of these films was studied in some detail. The films exhibited "lotus effect", mimicking natural non

  7. The Art of Teaching Social Studies with Film

    ERIC Educational Resources Information Center

    Russell, William B., III

    2012-01-01

    Teaching with film is a powerful and meaningful instructional strategy. This article discusses five classroom-tested methods for teaching with film: (1) film as a visual textbook, (2) film as a depicter of atmosphere, (3) film as an analogy, (4) film as a historiography, and (5) film as a springboard. Each of the methods discussed includes…

  8. Studies on atomic layer deposition of IRMOF-8 thin films

    SciTech Connect

    Salmi, Leo D. Heikkilä, Mikko J.; Vehkamäki, Marko; Puukilainen, Esa; Ritala, Mikko; Sajavaara, Timo

    2015-01-15

    Deposition of IRMOF-8 thin films by atomic layer deposition was studied at 260–320 °C. Zinc acetate and 2,6-naphthalenedicarboxylic acid were used as the precursors. The as-deposited amorphous films were crystallized in 70% relative humidity at room temperature resulting in an unknown phase with a large unit cell. An autoclave with dimethylformamide as the solvent was used to recrystallize the films into IRMOF-8 as confirmed by grazing incidence x-ray diffraction. The films were further characterized by high temperature x-ray diffraction (HTXRD), field emission scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), time-of-flight elastic recoil detection analysis (TOF-ERDA), nanoindentation, and energy-dispersive x-ray spectroscopy. HTXRD measurements revealed similar behavior to bulk IRMOF-8. According to TOF-ERDA and FTIR, composition of the films was similar to IRMOF-8. Through-porosity was confirmed by loading the films with palladium using Pd(thd){sub 2} (thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) as the precursor.

  9. Studies of falling annular films, Parts I and II

    SciTech Connect

    Roidt, R.M.; Evans, R.A.

    1989-01-01

    New environmental requirements and restrictions necessitate exploration of new methods for controlling and containing various chemicals and chemical reactions. A novel method of exercising such control is based upon the cylindrical film reactor, a device originally studied as a confinement for a fusion reactor. The films used in these confinement models were quite thick relative to the radius of the cylindrical film so that the experimental work was generally not relevant to the design of chemical reactors where, for purposes of efficiency, the minimum confinement flowrate is desired. An annular, cylindrical, falling film converges into a single stream due to surface tension forces; this convergence length determines the volume of the reactor. Entrainment of gases from within the film volume to the exit stream allows a constant feed of gas into the reactor volume so that gas phase reactions may be carried out without contact with surrounding atmosphere. The present work is an experimental investigation of the pertinent parameters and stability criteria for thin, falling, cylindrical films. We find that, while only for relatively restricted ratios of gas to liquid flow rates do stable reaction volumes exist, most of this range lies within flow rate limits which may be of use in gas-liquid chemical reactors. 12 refs., 33 figs.

  10. Film-In: A Study of the Movies, A Resource Unit.

    ERIC Educational Resources Information Center

    Vaughn, Mary Beth

    This resource guide to films contains four study units for high school students dealing with (1) reasons for film popularity--involvement; (2) film language--visual, motion, sound; (3) thematic study--a perspective on war; (4) film criticism--sensitivity and awareness. Each unit provides suggestions for length of study, purposes, descriptions of…

  11. Polycrystalline Thin Film Device Degradation Studies

    SciTech Connect

    Albin, D. S.; McMahon, T. J.; Pankow, J. W.; Noufi, R.; Demtsu, S. H.; Davies, A.

    2005-11-01

    Oxygen during vapor CdCl2 (VCC) treatments significantly reduced resistive shunts observed in CdS/CdTe polycrystalline devices using thinner CdS layers during 100 deg C, open-circuit, 1-sun accelerated stress testing. Cu oxidation resulting from the reduction of various trace oxides present in as-grown and VCC treated films is the proposed mechanism by which Cu diffusion, and subsequent shunts are controlled. Graphite paste layers between metallization and CdTe behave like diffusion barriers and similarly benefit device stability. Ni-based contacts form a protective Ni2Te3 intermetallic layer that reduces metal diffusion but degrades performance through increased series resistance.

  12. A finite element study of piezoelectric thin films on substrates

    NASA Astrophysics Data System (ADS)

    Liu, Bo

    The overall goal of this work has been mainly to advance the understanding of the degradation in the response of piezoelectric thin films after they are deposited on substrates. To have better understanding of the difference in the response between free standing piezoelectric films and those deposited on a substrate, we calculated the normalized "effective" piezoelectric coefficients for BT/MgO, PZT/STO and ZnO/STO respectively. We also studied the impact on the effective coefficients due to the components of the bulk material's piezoelectric coefficients. After studying the clamping effects of the substrate, lattice mismatch, stiffness of the films and the substrates, we found that a periodic structure of piezoelectric thin films on substrates is a useful approach to overcome the degradation of the piezoresponse. Further, if non-piezoelectric islands are inserted between the periodic piezoelectric islands, there is an additional contribution that improves the piezoresponse of the piezoelectric films; we refer to this structure as a bi-island periodic structure. The bi-island structure may also be used as a hybrid device if the non-piezoelectric islands have special properties, e.g. piezomagnetism, ferromagnetism and shape memory. The hybrid device may thus be used for signal transduction, e.g. converting electrical signals to magnetic/mechanical/thermal signals and vice-versa, as well as energy harvesting.

  13. Microwave study of superconducting Sn films above and below percolation

    NASA Astrophysics Data System (ADS)

    Beutel, Manfred H.; Ebensperger, Nikolaj G.; Thiemann, Markus; Untereiner, Gabriele; Fritz, Vincent; Javaheri, Mojtaba; Nägele, Jonathan; Rösslhuber, Roland; Dressel, Martin; Scheffler, Marc

    2016-08-01

    The electronic properties of superconducting Sn films ({T}{{c}}≈ 3.8 {{K}}) change significantly when reducing the film thickness down to a few {nm}, in particular close to the percolation threshold. The low-energy electrodynamics of such Sn samples can be probed via microwave spectroscopy, e.g. with superconducting stripline resonators. Here we study Sn thin films, deposited via thermal evaporation—ranging in thickness between 38 and 842 {nm}—which encompasses the percolation transition. We use superconducting Pb stripline resonators to probe the microwave response of these Sn films in a frequency range between 4 and 20 {GHz} at temperatures from 7.2 down to 1.5 {{K}}. The measured quality factor of the resonators decreases with rising temperature due to enhanced losses. As a function of the sample thickness we observe three regimes with significantly different properties: samples below percolation, i.e. ensembles of disconnected superconducting islands, exhibit dielectric properties with negligible losses, demonstrating that macroscopic current paths are required for appreciable dynamical conductivity of Sn at GHz frequencies. Thick Sn films, as the other limit, lead to low-loss resonances both above and below T c of Sn, as expected for bulk conductors. But in an intermediate thickness regime, just above percolation and with labyrinth-like morphology of the Sn, we observe a quite different behavior: the superconducting state has a microwave response similar to the thicker, completely covering films with low microwave losses; but the metallic state of these Sn films is so lossy that resonator operation is suppressed completely.

  14. Cratering Studies in Thin Plastic Films

    NASA Astrophysics Data System (ADS)

    Shu, Anthony; Bugiel, S.; Gruen, E.; Horanyi, M.; Munsat, T.; Srama, R.; Colorado CenterLunar Dust; Atmospheric Studies (CCLDAS) Team

    2013-10-01

    Thin plastic films, such as Polyvinylidene Fluoride (PVDF), have been used as protective coatings or dust detectors on a number of missions including the Dust Counter and Mass Analyzer (DUCMA) instrument on Vega 1 and 2, the High Rate Detector (HRD) on the Cassini Mission, and the Student Dust Counter (SDC) on New Horizons. These types of detectors can be used on the lunar surface or in lunar orbit to detect dust grain size distributions and velocities. Due to their low power requirements and light weight, large surface area detectors can be built for observing low dust fluxes. The SDC dust detector is made up of a permanently polarized layer of PVDF coated on both sides with a thin layer (≈ 1000 Å) of aluminum nickel. The operation principle is that a micrometeorite impact removes a portion of the metal surface layer exposing the permanently polarized PVDF underneath. This causes a local potential near the crater changing the surface charge of the metal layer. The dimensions of the crater determine the strength of the potential and thus the signal generated by the PVDF. The theoretical basis for signal interpretation uses a crater diameter scaling law which was not intended for use with PVDF. In this work, a crater size scaling law has been experimentally determined, and further simulation work is being done to enhance our understanding of the mechanisms of crater formation. Two Smoothed Particle Hydrodynamics (SPH) codes are being evaluated for use as a simulator for hypervelocity impacts: Ansys Autodyn and LS-Dyna from the Livermore Software Technology Corp. SPH is known to be well suited to the large deformities found in hypervelocity impacts. It is capable of incorporating key physics phenomena, including fracture, heat transfer, melting, etc. Furthermore, unlike Eulerian methods, SPH is gridless allowing large deformities without the inclusion of unphysical erosion algorithms. Experimental results and preliminary simulation results and conclusions will be

  15. Study of critical current density in superconducting magnesium diboride films grown by ex situ annealing of CVD boron films

    NASA Astrophysics Data System (ADS)

    Hanna, Mina

    MgB2 films have been processed by different techniques, the most successful of which include the hybrid physical-chemical vapor deposition (HPCVD) as well as the ex situ high temperature annealing of boron films in Mg vapor. The advantage of the ex situ method is that it allows the coating of MgB2 on large and complex surfaces, such as superconducting radio frequency (RF) cavities. However, it has always been realized that HPCVD films can carry higher J c than the ex situ annealed films. In this research, we succeeded in fabricating high quality MgB2 films by the ex situ annealing technique that produced a Jc value as high as 1.8 x 106 A/cm 2 for 1 mum thick film at 20 K and self-field. This high Jc value is, however, considerably reduced at higher thicknesses similar to that observed in YBCO coated conductors. In order to understand the mechanisms responsible for J c decrease with increasing film thickness, we studied the Jc behavior as a function of thickness in MgB2 films fabricated by ex situ annealing at 840°C of boron films, grown by chemical vapor deposition, in Mg vapor. The film thickness ranged between 300 nm and 10 mum. The values of Jc for these films ranged from 1.2 x 107 A/cm2 for 300 nm to 1.9 x 105 A/cm2 for 10 mum film thickness at 20 K and self-field. In addition, the results show that critical current (Ic) reaches a maximum value of 728 A/cm width at ˜1 mum thick MgB2 film at 20 K and self-field. These results of Jc and Ic behaviors with higher thickness are interpreted in terms of impurity diffusion during annealing and microstructural degradation for thicker films.

  16. Using stressful films to analyze risk factors for PTSD in analogue experimental studies--which film works best?

    PubMed

    Weidmann, Anke; Conradi, Ania; Groger, Kathrin; Fehm, Lydia; Fydrich, Thomas

    2009-10-01

    To understand mental disorders, analogue paradigms provide an indispensable contribution. In posttraumatic stress disorder (PTSD), the stressful film paradigm is a frequently used analogue approach: Films depicting traumatic events are shown to non-clinical participants in order to elicit stress responses analogue to responses to traumatic events in real life. Previous studies used a large variety of films, which is problematic with regard to the comparability of results. The main goal of this study was to identify a film clip that (a) consistently provokes stress reactions and (b) provokes reactions that are as similar as possible to traumatic stress. We randomly exposed 105 male and female participants to one of four stressful films, differing, e.g., in content and origin. Intrusive memories of the film, reported immediately after the film and during a diary phase of three days, as well as distress, heart rate, and several mood states were measured. A film clip depicting rape elicited the most consistent reactions that were characterized by a higher heart rate, more distress and more intrusive memories, compared to the other three clips. Intrusive memories across all films were especially related to an increase in heart rate and disgust in response to the film. PMID:19347765

  17. Nanoindentation and scratch studies on magnetron sputtered Ti thin films.

    PubMed

    Kataria, S; Ramaseshan, R; Dash, S; Tyagi, A K

    2009-09-01

    Ti thin films sputter deposited on D9 steel at two different temperatures were studied for their mechanical behavior under static and sliding contact conditions using nanoindentation and scratch tests. The film hardness measured at the surface of the coatings exhibited a value of 2.5 GPa, for both conditions. From the scratch test, it is understood that coatings deposited at 200 degrees C substrate temperature showed superior adhesion strength. Critical load to failure for these coatings was evaluated at 2 N. PMID:19928247

  18. In situ studies of grain growth in thin metal films

    SciTech Connect

    Nichols, C.S.; Mansuri, C.M. . Dept. of Materials Science and Engineering); Townsend, S.J. . Dept. of Physics); Smith, D.A. . T.J. Watson Research Center)

    1993-06-01

    Grain growth in thin films of aluminum has been studied using in situ transmission electron microscopy and a heating stage. Videotapes taken during grain growth were analyzed with the intent of searching for the predominant local rearrangement processes responsible for growth. Evolution of a soap froth can be decomposed into only two elementary local topology rearranging events. The authors have found numerous exceptions to prevailing theories that compare grain growth in thin films to the evolution of such froths. These observations suggest that a more complete picture of grain growth is necessary and that such a theory must include more complex local rearrangement processes.

  19. Experimental study of flapping jets in a soap film

    NASA Astrophysics Data System (ADS)

    Lee, Julia; Kim, Ildoo; Mandre, Shreyas

    2015-11-01

    Plateau and Rayleigh's observation and explanation on jet instability have inspired us over the years and there has been a significant advance in understanding the jet dynamics. Here, we present a quasi-two-dimensional experimental study of flapping jets in a soap film. Newtonian and non-Newtonian solutions are injected in a flowing soap film. Thinning, break-ups, and beads-on-a-string of the jets, and axisymmetric vortices shredded from the flapping jets are visualized. We employ PIV of the flow motion around the jets to gain an understanding of the roles of instabilities in the flow.

  20. Infrared spectroscopic study of sputtered tungsten oxide films

    SciTech Connect

    Paul, J.L.; Lassegues, J.C. )

    1993-10-01

    Recent infrared and Raman spectroscopic studies of various tungsten oxide films concluded either the formation of W=O terminal bonds or the transformation of such bonds into W-OH groups upon proton insertion. The infrared transmission and reflection spectra of bleached and colored sputtered films were reinvestigated in order to resolve the previous contradictory interpretations and for better insight into the mechanism of electrochromism at the molecular level. The new results confirm the first interpretation and allow us to show that H[sup +] or Li[sup +] insertion creates shorter ([approximately]1.7[angstrom]) and longer ([approximately]2 [angstrom]) W-O bonds around the W[sup 5+] centers. These results are in agreement with the concepts of small polaron and of intervalence charge transfer mechanism. They illustrate the local lattice distortion around a W[sup 5+] site. Aging of the initial films has also been followed and characterized by H/D in situ isotopic exchange.

  1. Mössbauer and SEM study of Fe Al film

    NASA Astrophysics Data System (ADS)

    Sebastian, Varkey; Sharma, Ram Kripal; Lakshmi, N.; Venugopalan, K.

    2006-04-01

    Fe Al alloy with Fe/Al ratio of 3:1 was first prepared by argon arc melting. It was subsequently coated on glass slide and cellophane tape using an electron beam gun system to have a thickness of 2,000 Å. X-ray diffraction spectrum of the coated sample indicates a definite texture for the film with a preferential growth along the Fe(110) plane. SEM micrographs of the film showed the presence of nano islands of nearly 3 × 1012/m2 surface density. Composition of different parts of the film was determined using EDAX. Room temperature Fe-57 Mössbauer spectrum of coated sample showed the presence a quadrupole doublet with a splitting of 0.46 mm/s, which is typical of Al-rich iron compounds. MOKE study shows an in-plane magnetic moment.

  2. Cratering Studies in Thin Plastic Films

    NASA Astrophysics Data System (ADS)

    Shu, A. J.; Bugiel, S.; Gruen, E.; Horanyi, M.; Munsat, T. L.; Srama, R.

    2014-12-01

    Thin plastic films, such as Polyvinylidene Fluoride (PVDF), have been used as protective coatings or dust detectors on a number of missions including the Dust Counter and Mass Analyzer (DUCMA) instrument on Vega 1 and 2, the High Rate Detector (HRD) on the Cassini Mission, and the Student Dust Counter (SDC) on New Horizons. These types of detectors can be used on the lunar surface or in lunar orbit to detect dust grain size distributions and velocities. Due to their low power requirements and light weight, large surface area detectors can be built for observing low dust fluxes. The SDC dust detector is made up of a permanently polarized layer of PVDF coated on both sides with a thin layer (≈ 1000 Å) of aluminum nickel. The operation principle is that a micrometeorite impact removes a portion of the metal surface layer exposing the permanently polarized PVDF underneath. This causes a local potential near the crater changing the surface charge of the metal layer. The dimensions and shape of the crater determine the strength of the potential and thus the signal generated by the PVDF. The theoretical basis for signal interpretation uses a crater diameter scaling law which was not intended for use with PVDF. In this work, a crater size scaling law has been experimentally determined, and further simulation work is being done to enhance our understanding of the mechanisms of crater formation. LS-Dyna, a smoothed particle hydrodynamics (SPH) code from the Livermore Software Technology Corp. was chosen to simulate micrometeorite impacts. It is capable of incorporating key physics phenomena, including fracture, heat transfer, melting, etc. Furthermore, unlike Eulerian methods, SPH is gridless allowing large deformities without the inclusion of unphysical erosion algorithms. Material properties are accounted for using the Grüneisen Equation of State. The results of the SPH model can then be fed into electrostatic relaxation models to enhance the fidelity of interpretation

  3. Cratering Studies in Thin Plastic Films

    NASA Astrophysics Data System (ADS)

    Shu, A. J.; Bugiel, S.; Gruen, E.; Hillier, J.; Horanyi, M.; Munsat, T. L.; Srama, R.

    2013-12-01

    Thin plastic films, such as Polyvinylidene Fluoride (PVDF), have been used as protective coatings or dust detectors on a number of missions including the Dust Counter and Mass Analyzer (DUCMA) instrument on Vega 1 and 2, the High Rate Detector (HRD) on the Cassini Mission, and the Student Dust Counter (SDC) on New Horizons. These types of detectors can be used on the lunar surface or in lunar orbit to detect dust grain size distributions and velocities. Due to their low power requirements and light weight, large surface area detectors can be built for observing low dust fluxes. The SDC dust detector is made up of a permanently polarized layer of PVDF coated on both sides with a thin layer (≈ 1000 Å) of aluminum nickel. The operation principle is that a micrometeorite impact removes a portion of the metal surface layer exposing the permanently polarized PVDF underneath. This causes a local potential near the crater changing the surface charge of the metal layer. The dimensions and shape of the crater determine the strength of the potential and thus the signal generated by the PVDF. The theoretical basis for signal interpretation uses a crater diameter scaling law which was not intended for use with PVDF. In this work, a crater size scaling law has been experimentally determined, and further simulation work is being done to enhance our understanding of the mechanisms of crater formation. LS-Dyna, a smoothed particle hydrodynamics (SPH) code from the Livermore Software Technology Corp. was chosen to simulate micrometeorite impacts. SPH is known to be well suited to the large deformities found in hypervelocity impacts. It is capable of incorporating key physics phenomena, including fracture, heat transfer, melting, etc. Furthermore, unlike Eulerian methods, SPH is gridless allowing large deformities without the inclusion of unphysical erosion algorithms. Material properties are accounted for using the Grüneisen Equation of State. The results of the SPH model can

  4. Photoemission Spectroscopic Study of Cesium Telluride Thin Film Photocathode

    SciTech Connect

    Sugiyama, Harue; Ogawa, Koji; Azuma, Junpei; Takahashi, Kazutoshi; Kamada, Masao

    2009-08-04

    The photoemission spectroscopy using synchrotron radiation has been carried out to study the high quantum efficiency and long working lifetime of cesium telluride (Cs{sub x}Te{sub y}) thin film photocathode. The electron affinity derived from the observed energy-distribution curves provides an important hint for long persistency of the photocathode.

  5. Radiochromic films for dental CT dosimetry: a feasibility study.

    PubMed

    Rampado, O; Bianchi, S D; Peruzzo Cornetto, A; Rossetti, V; Ropolo, R

    2014-02-01

    Dental CT dose evaluations are commonly performed using thermoluminescent dosimeters (TLD) inside anthropomorphic phantoms. Radiochromic films with good sensitivity in the X-ray diagnostic field have recently been developed and are commercially available as GAFCHROMIC XR-QA. There are potential advantages in the use of radiochromic films such as a more comprehensive dosimetry thanks to the adjustable size of the film samples. The purpose of this study was to investigate the feasibility of using radiochromic films for dental CT dose evaluations. Film samples were cut with a width of 5mm and a length of 25 mm (strips), the same size as the Alderson Rando anthropomorphic phantom holes used in this study. Dental CT dose measurements were performed using simultaneously both TLD and radiochromic strips in the same phantom sites. Two equipment types were considered for dental CT examinations: a 16 slice CT and a cone beam CT. Organ equivalent doses were then obtained averaging the measurements from the sites of the same organ and effective doses were calculated using ICRP 103 weighting factors. The entire procedure was repeated four times for each CT in order to compare also the repeatability of the two dosimeter types. A linear correlation was found between the absorbed dose evaluated with radiochromic films and with TLD, with slopes of 0.930 and 0.944 (correlation r>0.99). The maximum difference between the two dosimeter's measurements was 25%, whereas the average difference was 7%. The measurement repeatability was comparable for the two dosimeters at cumulative doses above 15 mGy (estimated uncertainty at 1 sigma level of about 5%), whereas below this threshold radiochromic films show a greater dispersion of data, of about 10% at 1 sigma level. We obtained, using respectively Gafchromic and TLD measurements, effective dose values of 107 μSv and 117 μSv (i.e. difference of 8.6%) for the cone beam CT and of 523 μSv and 562 μSv (i.e. difference of 7%) for the

  6. Nanocrystalline zinc ferrite films studied by magneto-optical spectroscopy

    SciTech Connect

    Lišková-Jakubisová, E. Višňovský, Š.; Široký, P.; Hrabovský, D.; Pištora, J.; Sahoo, Subasa C.; Prasad, Shiva; Venkataramani, N.; Bohra, Murtaza; Krishnan, R.

    2015-05-07

    Ferrimagnetic Zn-ferrite (ZnFe{sub 2}O{sub 4}) films can be grown with the ferromagnetic resonance linewidth of 40 Oe at 9.5 GHz without going through a high temperature processing. This presents interest for applications. The work deals with laser ablated ZnFe{sub 2}O{sub 4} films deposited at O{sub 2} pressure of 0.16 mbar onto fused quartz substrates. The films about 120 nm thick are nanocrystalline and their spontaneous magnetization, 4πM{sub s}, depends on the nanograin size, which is controlled by the substrate temperature (T{sub s}). At T{sub s} ≈ 350 °C, where the grain distribution peaks around ∼20–30 nm, the room temperature 4πM{sub s} reaches a maximum of ∼2.3 kG. The films were studied by magnetooptical polar Kerr effect (MOKE) spectroscopy at photon energies between 1 and 5 eV. The complementary characteristics were provided by spectral ellipsometry (SE). Both the SE and MOKE spectra confirmed ferrimagnetic ordering. The structural details correspond to those observed in MgFe{sub 2}O{sub 4} and Li{sub 0.5}Fe{sub 2.5}O{sub 4} spinels. SE experiments confirm the insulator behavior. The films display MOKE amplitudes somewhat reduced with respect to those in Li{sub 0.5}Fe{sub 2.5}O{sub 4} and MgFe{sub 2}O{sub 4} due to a lower degree of spinel inversion and nanocrystalline structure. The results indicate that the films are free of oxygen vacancies and Fe{sup 3+}-Fe{sup 2+} exchange.

  7. A Controlled Study on the Correlation between Tear Film Volume and Tear Film Stability in Diabetic Patients

    PubMed Central

    Khalil, Noha M.; El-Gendy, Heba A.

    2016-01-01

    Purpose. To assess the tear film quantity and correlate it with the quality and stability of the tear film in diabetics and compare them to age matched controls. Introduction. Diabetes affects tear film parameters in multiple ways. Poor metabolic control and neuropathy are postulated factors. To further understand how diabetes affects tear film parameters this study was conducted. Subjects and Methods. Tear meniscus height was measured by anterior segment OCT, along with tear thinning time, a subtype of noninvasive tear break-up time, and blinking rate per minute which were all recorded for 22 diabetic patients. Correlations between these tear film parameters were studied and then compared to 16 age matched controls. Results. A statistically significant difference was found in blinking rate between the diabetic and the control group (P = 0.002), with higher blinking rate among diabetics. All tear film parameters were negatively correlated with duration of diabetes. A positive correlation was found between tear film volume and stability. Conclusion. Diabetes affects the tear film in various ways. Diabetics should be examined for dry eye signs even in absence of symptoms which may be masked by associated neuropathy. Duration of diabetes has an impact on tear film status. PMID:27034823

  8. Experimental study of graphitic nanoribbon films for ammonia sensing

    NASA Astrophysics Data System (ADS)

    Johnson, Jason L.; Behnam, Ashkan; An, Yanbin; Pearton, S. J.; Ural, Ant

    2011-06-01

    We fabricate and study the ammonia sensing properties of graphitic nanoribbon films consisting of multi-layer graphene nanoribbons. These films show very good sensitivity to parts-per-million (ppm) level concentrations of ammonia, which is further enhanced by platinum functionalization, resulting in a relative resistance response of ˜70% when exposed to 50 ppm ammonia. In addition, the sensing response exhibits excellent repeatability and full recovery in air. We also study in detail the dependence of the sensing response on ammonia concentration and temperature. We find that the relative resistance response of the graphitic nanoribbon films shows a power-law dependence on the ammonia concentration, which can be explained based on the Freundlich isotherm. The activation energy obtained from an Arrhenius plot of the temperature-dependent measurements is ˜50 meV, which is consistent with the theoretical calculations of the adsorption energies of ammonia on large graphene sheets and nanoribbons. Their simple and low-cost fabrication process and good sensing response open up the possibility of using graphitic nanoribbon films for large-scale sensing applications.

  9. Bulk and thin films of FeTe: A Moessbauer study

    NASA Technical Reports Server (NTRS)

    Escue, W. T.; Aggarwal, K.; Mendiratta, R. G.

    1977-01-01

    Studies of bulk and thin films of FeTe using Moessbauer spectroscopy showed that FeTe has one noncubic Fe (+2) site which is 3d2 4s 4p3 hybridized. The presence of dangling bands was indicated in spectra of FeTe thin films. The films showed a tendency of texture formation. The substrate was observed to influence the film structure and nature of bonds in films.

  10. Discrete component bonding and thick film materials study

    NASA Technical Reports Server (NTRS)

    Kinser, D. L.

    1975-01-01

    The results are summarized of an investigation of discrete component bonding reliability and a fundamental study of new thick film resistor materials. The component bonding study examined several types of solder bonded components with some processing variable studies to determine their influence upon bonding reliability. The bonding reliability was assessed using the thermal cycle: 15 minutes at room temperature, 15 minutes at +125 C 15 minutes at room temperature, and 15 minutes at -55 C. The thick film resistor materials examined were of the transition metal oxide-phosphate glass family with several elemental metal additions of the same transition metal. These studies were conducted by preparing a paste of the subject composition, printing, drying, and firing using both air and reducing atmospheres. The resulting resistors were examined for adherence, resistance, thermal coefficient of resistance, and voltage coefficient of resistance.

  11. Structural, Magnetic and Spectroscopic Studies of Thin Manganite Films

    NASA Astrophysics Data System (ADS)

    Tyson, T. A.

    2003-03-01

    Starting from early experiments [1], evidence has been found for a close coupling of strain and the magnetotransport properties of manganite films. The characteristic feature found is that the metal to insulator transition temperature (TMI) is suppressed in very thin films [2]. In addition, studies show that the magnetic transition temperature (Tc) and TMI decouple in ultrathin films [3]. Systematic magnetization studies reveal that strain induces strong magnetic anisotropy [4]. Theoretical work also points to the sensitivity of Tc to biaxial strain [5]. Most studies have focused on single bulk properties. In order to understand the correlations between strain and the transport and magnetic properties we have examined the structure of films on multiple length scales. The local structure of films have been studies by x-ray absorption spectroscopy. The long -range structure has been studied by high-resolution x-ray diffraction and the microstructure has been studied by AFM measurements. These measurements are correlated with bulk magnetization and transport studies. Insight is gained on the evolution of lattice strain and Jahn-Teller distortions with thickness. Direct evidence is found for the arrest of charge ordering with strain and the existence of strain induced insulating regions of films. The magnetic ordering and transport properties as a function of strain as compared with bandstructure calculations. This work is supported by NSF Career Grant DMR-9733862 and DMR-0209243. Collaborators: Q. Qian, M. Deleon (NJIT), C. Dubourdiu (CNRS), J. Bai (ORNL), W. Prellier, A. Biswas, R. L. Greene (U. Maryland) [1] S. Jin et al., Appl. Phys. Lett. 67, 557 (1995). [2] (a) J. Z. Sun et al. Appl. Phys. Lett. 74, 3017 (1999). (b) F. S. Razi et al., Appl. Phys. Lett 76, 155 (2000) [3] J. Aarts et al., Appl. Phys. Lett. 72, 2975 (1998). (b) R. A. Rao et al., J. Appl. Phys. 85, 4794 (1999). [4] (a) X. W. Wu et al., Phys. Rev. B 61, 501 (2000). (b) J. O'Donnell et al., Appl. Phys

  12. FMR study of thin film FeGe skyrmionic material

    NASA Astrophysics Data System (ADS)

    Bhallamudi, Vidya P.; Page, Michael R.; Gallagher, James; Purser, Carola; Schulze, Joseph; Yang, Fengyuan; Hammel, P. Chris

    Magnetic Skyrmions have attracted intense interest due to their novel topological properties and the potential for energy efficient computing. Magnetic dynamics play an important part in enabling some of these functionalities. Understanding these dynamics can shed light on the interplay of the various magnetic interactions that exist in these materials and lead to a rich magnetic phase diagram, including the Skyrmion phase. We have grown phase-pure FeGe epitaxial films on Si (111) and studied them using ferromagnetic resonance (FMR). FeGe has one of the highest recorded skyrmion transition temperatures, close to room temperature, and thin films are known to further stabilize the Skyrmion phase in the magnetic field-temperature space. We have performed cavity-based single frequency FMR from liquid nitrogen to room temperature on 120 nm thick films in both in-plane and out-of-plane geometries. The resulting complex spectra are consistent with those reported in literature for the bulk material and can be understood in terms of a conical model for the magnetism. Variable temperature broadband spectroscopy and measurements on thinner films, to better identify the various magnetic phases and their dynamic behavior, are ongoing and their progress will be discussed. Funding for this research was provided by the Center for Emergent Materials: an NSF MRSEC under Award Number DMR-1420451.

  13. Ellipsometric study of oxide films formed on LDEF metal samples

    NASA Technical Reports Server (NTRS)

    Franzen, W.; Brodkin, J. S.; Sengupta, L. C.; Sagalyn, P. L.

    1992-01-01

    The optical constants of samples of six different metals (Al, Cu, Ni, Ta, W, and Zr) exposed to space on the Long Duration Exposure Facility (LDEF) were studied by variable angle spectroscopic ellipsometry. Measurements were also carried out on portions of each sample which were shielded from direct exposure by a metal bar. A least-squares fit of the data using an effective medium approximation was then carried out, with thickness and composition of surface films formed on the metal substrates as variable parameters. The analysis revealed that exposed portions of the Cu, Ni, Ta, and Zr samples are covered with porous oxide films ranging in thickness from 500 to 1000 A. The 410 A thick film of Al2O3 on the exposed Al sample is practically free of voids. Except for Cu, the shielded portions of these metals are covered by thin non-porous oxide films characteristic of exposure to air. The shielded part of the Cu sample has a much thicker porous coating of Cu2O. The tungsten data could not be analyzed.

  14. Extension of Radiochromic Film Dosimetry to Three Dimensions: A Feasibility Study

    SciTech Connect

    Adamczyk, S.; Skorska, M.

    2007-11-26

    The feasibility of measuring dose distributions in three-dimensions using Gafchromic EBT film was studied. A stack of film was used as tomographic dosimeter. The response of film (4x4 cm{sup 2}) placed between a stack of Gafchromic EBT films and slabs of polystyrene phantom was tested. Differences in film response for two different photon beam qualities, 6 MV and 25 MV, were observed. Measurements with 6 MV beam quality revealed that for different field sizes and depths there were no changes in response of EBT Gafchromic film when placed between polystyrene plates or sandwiched between other films. However, in the case of 25 MV beam quality, a statistically significant over-response was found for film placed in stack. We conclude that stacked-film dosimetry is feasible at 6 MV. For 25 MV photon beam quality the stack of films showed different properties than the polystyrene slabs of the same height.

  15. A study of Ag/Ag(100) thin film growth with scanning tunneling microscopy

    SciTech Connect

    Wen, J.

    1995-11-01

    Thin films are attracting more and more attention in both the industrial and scientific communities. Many applications of thin films have been developed in industry. By using various growth methods, thin films can be used in optics, microelectronic devices, magnetic recording media, and as protective coatings. In order to improve existing applications and to find new ones, it is essential to understand what makes them so useful in applications and what factors affect their properties. Therefore, an understanding of film growth processes is necessary. Scientifically, many fundamental interactions, such as the interaction between the atoms that comprise the film and substrate, or the interaction between film atoms, are of great interest to surface scientists; studies of these interactions can provide dramatic insights into the nature of thin films and therefore, can further drive technology forward. In every application, the film structures, including morphology and microstructure, and adhesion between film and substrate are critical to the film`s properties and therefore its performance. Studies of the mechanisms that control film morphology, microstructure and adhesion thus are important. Film growth kinetics can provide important information regarding the film structure and adhesion. Film growth is an atomistic process. The chemistry and physics of the system can be better understood if the information provided is at an atomic level.

  16. Using Systemic Functional Linguistics in Academic Writing Development: An Example from Film Studies

    ERIC Educational Resources Information Center

    Donohue, James P.

    2012-01-01

    On film studies courses, students are asked to treat as objects of study the same films which they may more commonly experience as entertainment. To explore the role of academic writing in this, an action research project was carried out on a university film studies course using a systemic functional linguistics approach. This paper presents a key…

  17. Studies on nickel-tungsten oxide thin films

    SciTech Connect

    Usha, K. S.; Sivakumar, R.; Sanjeeviraja, C.

    2014-10-15

    Nickel-Tungsten oxide (95:5) thin films were prepared by rf sputtering at 200W rf power with various substrate temperatures. X-ray diffraction study reveals the amorphous nature of films. The substrate temperature induced decrease in energy band gap with a maximum transmittance of 71%1 was observed. The Micro-Raman study shows broad peaks at 560 cm{sup −1} and 1100 cm{sup −1} correspond to Ni-O vibration and the peak at 860 cm{sup −1} can be assigned to the vibration of W-O-W bond. Photoluminescence spectra show two peaks centered on 420 nm and 485 nm corresponding to the band edge emission and vacancies created due to the addition of tungsten, respectively.

  18. Studies on nickel-tungsten oxide thin films

    NASA Astrophysics Data System (ADS)

    Usha, K. S.; Sivakumar, R.; Sanjeeviraja, C.

    2014-10-01

    Nickel-Tungsten oxide (95:5) thin films were prepared by rf sputtering at 200W rf power with various substrate temperatures. X-ray diffraction study reveals the amorphous nature of films. The substrate temperature induced decrease in energy band gap with a maximum transmittance of 71%1 was observed. The Micro-Raman study shows broad peaks at 560 cm-1 and 1100 cm-1 correspond to Ni-O vibration and the peak at 860 cm-1 can be assigned to the vibration of W-O-W bond. Photoluminescence spectra show two peaks centered on 420 nm and 485 nm corresponding to the band edge emission and vacancies created due to the addition of tungsten, respectively.

  19. Partial discharge degradation and breakdown studies in polypropylene films

    SciTech Connect

    Thomas, B.; Nema, R.S.

    1996-12-31

    Internal partial discharge characteristics are investigated on impregnated polypropylene films containing artificial cavity of well-defined dimensions, immersed in oil. Electrical breakdown studies are carried out at step-wise rising stress to evaluate constants of inverse power law model. Partial discharge pulse distribution patterns are acquired using PC interfaced multichannel analyzer and statistical analysis of the discharge pulse spectrum is done by using 3-parameter Weibull distribution function. The results are compared with that for unimpregnated samples in air.

  20. Feasibility study of the separation of chlorinated films from plastic packaging wastes

    SciTech Connect

    Reddy, Mallampati Srinivasa; Yamaguchi, Takefumi; Okuda, Tetsuji; Tsai, Tsung-Yueh; Nakai, Satoshi; Nishijima, Wataru; Okada, Mitsumasa

    2010-04-15

    This study describes the possible separation of chlorinated plastic films (PVC and PVDC) from other heavy plastic packaging waste (PPW) by selective twist formation and gravity separation. Twists formation was mechanically induced in chlorinated plastic films, whereas twist formation did not occur in PS and PET films. After twist formation, all the films had the apparent density of less than 1.0 g/cm{sup 3} and floated in water even though the true density was more than 1.0 g/cm{sup 3}. However, the apparent density of the PS and the PET films increased with agitation to more than 1.0 g/cm{sup 3}, whereas that of chlorinated plastic films was kept less than 1.0 g/cm{sup 3}. The main reason would be the air being held inside the chlorinated plastic films which was difficult to be removed by agitation. Simple gravity separation after twist formation was applied for artificial film with 10 wt.% of the chlorinated films and real PPW films with 9 wt.% of the chlorinated films. About 76 wt.% of the artificial PPW films and 75 wt.% of real PPW films after the removal of PP and PE were recovered as settling fraction with 4.7 wt.% and 3.0 wt.% of chlorinated plastic films, respectively. These results indicate that simple gravity separation process after twist formation can be used to reduce the chlorinated plastic concentration from mixed heavy PPW films.

  1. [Comparative study of very high speed dental films].

    PubMed

    Benz, C

    1989-09-01

    Two new periapical films (Agfa Dentus M 4, Dupont Super Dozahn HS) were evaluated in comparison to Kodak-Ultraspeed and -Ektaspeed films. Dentus M 4 proved to be the fastest film available. Though higher sensitivity results in less contrast, faster films can in most cases be used with the advantage of maximal dose reduction. PMID:2637857

  2. Langmuir films study on lipid-containing artificial tears.

    PubMed

    Torrent-Burgués, J

    2016-04-01

    Lipid-containing artificial tears are a type of artificial tears that use lipid components in order to restore the lipid layer of the tear film. One of these components is lecithin which can be applied in spray solutions containing lecithin liposomes. In this work the behavior of three of these commercial tears based on lecithin, Innoxa, Opticalm and Optrex, are studied using the Langmuir technique. The obtained isotherms are presented, discussed and compared. This technique seems useful in order to see the film behavior of the lipid components of these tears and determine some important parameters such as fluidity and extension at the air-water interface, and allows us to discern differences between these commercial tears. Innoxa and Optrex tears are more similar to each other than to Opticalm tears. Opticalm presents more fluidity, probably due to the presence of more insaturations in the fatty acid chains of the phospholipids of the lecithin used in fabrication. PMID:26764100

  3. Analytical study of pressure balancing in gas film seals.

    NASA Technical Reports Server (NTRS)

    Zuk, J.

    1973-01-01

    Proper pressure balancing of gas film seals requires knowledge of the pressure profile load factor (load factor) values for a given set of design conditions. In this study, the load factor is investigated for subsonic and choked flow conditions, laminar and turbulent flows, and various seal entrance conditions. Both parallel sealing surfaces and surfaces with small linear deformation were investigated. The load factor for subsonic flow depends strongly on pressure ratio; under choked flow conditions, however, the load factor is found to depend more strongly on film thickness and flow entrance conditions rather than pressure ratio. The importance of generating hydrodynamic forces to keep the seal balanced under severe and multipoint operation is also discussed.

  4. Aging studies on thin tetra-phenyl butadiene films

    NASA Astrophysics Data System (ADS)

    Acciarri, R.; Canci, N.; Cavanna, F.; Segreto, E.; Szelc, A. M.

    2013-10-01

    Tetra-Phenyl Butadiene (TPB) is the most commonly used compound to wave-shift the 128 nm scintillation light of liquid Argon down to the visible spectrum. We present a study on the loss of conversion efficiency of thin TPB films evaporated on reflective foils when exposed to light and atmosphere. The efficiency of the films is measured and monitored with a dedicated set-up that uses gaseous Argon excited by alpha particles to produce 128 nm photons and working at room temperature. In particular we performed a two years long exposure of the samples to lab diffuse light and atmosphere. We also performed more controlled aging tests to investigate the effect of storing samples in a inert atmosphere.

  5. Combinatorial study of zinc tin oxide thin-film transistors

    SciTech Connect

    McDowell, M. G.; Sanderson, R. J.; Hill, I. G.

    2008-01-07

    Groups of thin-film transistors using a zinc tin oxide semiconductor layer have been fabricated via a combinatorial rf sputtering technique. The ZnO:SnO{sub 2} ratio of the film varies as a function of position on the sample, from pure ZnO to SnO{sub 2}, allowing for a study of zinc tin oxide transistor performance as a function of channel stoichiometry. The devices were found to have mobilities ranging from 2 to 12 cm{sup 2}/V s, with two peaks in mobility in devices at ZnO fractions of 0.80{+-}0.03 and 0.25{+-}0.05, and on/off ratios as high as 10{sup 7}. Transistors composed predominantly of SnO{sub 2} were found to exhibit light sensitivity which affected both the on/off ratios and threshold voltages of these devices.

  6. Bauschinger effect in thin metal films: Discrete dislocation dynamics study

    NASA Astrophysics Data System (ADS)

    Davoudi, Kamyar M.; Nicola, Lucia; Vlassak, Joost J.

    2014-01-01

    The effects of dislocation climb on plastic deformation during loading and unloading are studied using a two-dimensional discrete dislocation dynamics model. Simulations are performed for polycrystalline thin films passivated on both surfaces. Dislocation climb lowers the overall level of the stress inside thin films and reduces the work hardening rate. Climb decreases the density of dislocations in pile-ups and reduces back stresses. These factors result in a smaller Bauschinger effect on unloading compared to simulations without climb. As dislocations continue to climb at the onset of unloading and the dislocation density continues to increase, the initial unloading slope increases with decreasing unloading rate. Because climb disperses dislocations, fewer dislocations are annihilated during unloading, leading to a higher dislocation density at the end of the unloading step.

  7. Radio, Television and Film: The State of Study in the 1980s.

    ERIC Educational Resources Information Center

    Gomery, Douglas

    1985-01-01

    Analyzes two influential basic textbooks in the study of radio-television-film (RTVF): "Broadcasting in America" and "Film Art: An Introduction." Comments on how the RTVF organization impacts graduate education. (PD)

  8. Nanomechanical study of thin film nanocomposite and PVD thin films on polymer substrates for optical applications

    NASA Astrophysics Data System (ADS)

    Moghal, Jonathan; Bird, Andrew; Harris, Adrian H.; Beake, Ben D.; Gardener, Martin; Wakefield, Gareth

    2013-12-01

    The mechanical properties of ultrathin (<120 nm) films differ substantially from the bulk properties of the material and are also strongly substrate dependent. We compare the properties of two differing film systems; a high particle loading nanocomposite of silica and a multiple layer physical vapour deposition (PVD) coating by nanoindentation, nano-scratch and nano-impact followed by structural analysis. The work is undertaken on hardcoated polymer substrates and uses two types of anti-reflection coatings as test systems. The nanocomposite film comprises of a high (>50%) loading of silica nanoparticles in an inorganic binder, which demonstrates significant flex and elastic recovery whereas PVD films are subject to brittle failure even at low applied loads. Failure of the nanocomposite film, with the exception of minor plastic deformation, does not occur until the underlying substrate fails. Although the PVD film has a greater hardness than the nanocomposite, failure occurs at lower loads due to a number of toughness reducing factors including reduced modulus, modulus mismatch with the substrate and film thickness. The resistance of ultrathin films to external mechanical stresses is therefore related to a number of factors and not simply to film hardness, the most important of which are film structure and film mechanical matching to the substrate.

  9. A pilot study on the quality control of film processing in medical radiology laboratories in Greece.

    PubMed

    Hourdakis CJ-; Delakis, J; Kamenopoulou, V; Balougias, H; Papageorgiou, E

    2000-01-01

    The results of a pilot study on the quality of film processing in 80 medical diagnostic radiology laboratories all over Greece are presented. The sensitometric technique for the evaluation of processing has been used to calculate film's base + fog, maximum optical density, speed and contrast, parameters which describe the performance characteristics of automatic film processors and films. The mean values of the base + fog and the maximum optical density were well within the acceptance limits. The film speed was almost constant while the film contrast showed significant variation. PMID:10674786

  10. Thermodynamic study of argon films adsorbed on boron nitride

    SciTech Connect

    Migone, A.D.; Alkhafaji, M.T. ); Vidali, G. ); Karimi, M. )

    1993-03-15

    We have performed a detailed adsorption isotherm study of Ar on BN for temperatures between 65 and 80 K. The isothermal compressibility of the films was obtained from adsorption data. At monolayer coverages, a small isotherm substep is present at melting. We found two isothermal compressibility peaks in the first layer: a sharp peak, corresponding to the melting substep, and a smaller, broader peak that occurs at lower pressures. At multilayer coverages we found reentrant layering occurring in the third and fourth layers of the film. We compare our layering results with predictions for the preroughening transition. We also found a series of small steps in the isotherms between the second and third layers and between the third and fourth layers of the film. These small steps are evidence of individual layer melting for the second and third layers. Our results at monolayer and at multilayer coverages are extensively compared to those found for Ar on graphite. We have also performed calculations of the rare-gas--BN interaction potentials. Our calculations indicate the substrate corrugation is smaller for the rare-gas--BN systems than it is for the same rare gases on graphite. The implications of this result for the possible existence of monolayer-commensurate solids on BN are discussed.

  11. Spin polarized photoemission studies of interfacial and thin film magnetism

    SciTech Connect

    Johnson, P.D.; Brookes, N.B.; Chang, Y.; Garrison, K.

    1993-01-01

    Spin polarized photoemission is used to study the electronic structure of noble metals deposited on ferromagnetic substrates. Studies of Ag deposited on an Fe(001) substrate reveal a series of minority spin interface or quantum well states with binding energies dependent on the thickness of the silver. Similar behavior is observed for Cu films deposited on a fct Co(001) substrate. Tight-binding modeling reproduces many of the observations and shows that hybridization of the sp-bands with the noble metal d-bands cannot be ignored.

  12. Spin polarized photoemission studies of interfacial and thin film magnetism

    SciTech Connect

    Johnson, P.D.; Brookes, N.B.; Chang, Y.; Garrison, K.

    1993-06-01

    Spin polarized photoemission is used to study the electronic structure of noble metals deposited on ferromagnetic substrates. Studies of Ag deposited on an Fe(001) substrate reveal a series of minority spin interface or quantum well states with binding energies dependent on the thickness of the silver. Similar behavior is observed for Cu films deposited on a fct Co(001) substrate. Tight-binding modeling reproduces many of the observations and shows that hybridization of the sp-bands with the noble metal d-bands cannot be ignored.

  13. NMR Studies of 3He Films on Boron Nitride

    NASA Astrophysics Data System (ADS)

    Tang, Y.; Sullivan, N. S.

    2014-12-01

    We report the results of NMR studies of the dynamics of 3He adsorbed on hexagonal boron nitride. These studies can identify the phase transitions of the 2D films as a function of temperature. A thermally activated temperature dependence is observed for 2.6 < T < 8 K compared to a linear temperature dependence for 0.7 < T < 2.6 K. This linear dependence is consistent with that expected for thermal diffusion in a fluid for coverages of 0.4 - 0.6 of a monolayer.

  14. Moessbauer study in thin films of FeSi2 and FeSe systems

    NASA Technical Reports Server (NTRS)

    Escue, W. J.; Aggarwal, K.; Mendiratta, R. G.

    1978-01-01

    Thin films of FeSi2 and FeSe were studied using Moessbauer spectroscopy information regarding dangling bond configuration and nature of crystal structure in thin films was derived. A significant influence of crystalline aluminum substrate on film structure was observed.

  15. Optimization study of the femtosecond laser-induced forward-transfer process with thin aluminum films

    NASA Astrophysics Data System (ADS)

    Bera, Sudipta; Sabbah, A. J.; Yarbrough, J. M.; Allen, C. G.; Winters, Beau; Durfee, Charles G.; Squier, Jeff A.

    2007-07-01

    The parameters for an effective laser-induced forward-transfer (LIFT) process of aluminum thin films using a femtosecond laser are studied. Deposited feature size as a function of laser fluence, donor film thickness, quality of focus, and the pulse duration are varied, providing a metric of the most desirable conditions for femtosecond LIFT with thin aluminum films.

  16. Motion Pictures for the Study of India: A Guide to Classroom Films.

    ERIC Educational Resources Information Center

    Vestal, Theodore M.

    After a three year review of films on India available in the United States, the Resource Center offered this guide to those motion pictures adjudged best for use in American classrooms. There are twelve documentary films and four commercial feature films included for use at any level of school, college, or university study: Child of the Streets; A…

  17. Fostering Historical Thinking toward Civil Rights Movement Counter-Narratives: Documentary Film in Elementary Social Studies

    ERIC Educational Resources Information Center

    Buchanan, Lisa Brown

    2015-01-01

    This article describes how elementary preservice teachers used four documentary films to think historically about the United States Civil Rights Movement. The author situates the descriptive case study within research about historical thinking and documentary film, identifying the need for using documentary film to think historically in the…

  18. Scanning Tunneling Microscopy Studies of Diamond Films and Optoelectronic Materials

    NASA Technical Reports Server (NTRS)

    Perez, Jose M.

    1996-01-01

    We present a summary of the research, citations of publications resulting from the research and abstracts of such publications. We have made no inventions in the performance of the work in this project. The main goals of the project were to set up a Chemical Vapor Deposition (CVD) diamond growth system attached to an UltraHigh Vacuum (UHV) atomic resolution Scanning Tunneling Microscopy (STM) system and carry out experiments aimed at studying the properties and growth of diamond films using atomic resolution UHV STM. We successfully achieved these goals. We observed, for the first time, the atomic structure of the surface of CVD grown epitaxial diamond (100) films using UHV STM. We studied the effects of atomic hydrogen on the CVD diamond growth process. We studied the electronic properties of the diamond (100) (2x1) surface, and the effect of alkali metal adsorbates such as Cs on the work function of this surface using UHV STM spectroscopy techniques. We also studied, using STM, new electronic materials such as carbon nanotubes and gold nanostructures. This work resulted in four publications in refereed scientific journals and five publications in refereed conference proceedings.

  19. Polarized micro-Raman spectroscopy study of pentacene thin films

    NASA Astrophysics Data System (ADS)

    Stenger, Ingrid; Frigout, Alexandre; Tondelier, Denis; Geffroy, Bernard; Ossikovski, Razvigor; Bonnassieux, Yvan

    2009-03-01

    We report on polarized micro-Raman spectroscopy study of two pentacene thin films exhibiting different microstructures: a well-ordered sample and a more disordered one. We have investigated the frequency range of the intramolecular C-H bending modes in the plane of the pentacene molecule and proposed an interpretation of the Raman spectra. The use of symmetry properties of the two intramolecular (uncoupled) modes allowed us to unambiguously identify it among the five main contributions observed in this spectral range. The three other modes were assumed to be resulting from molecular coupling effect owing to their different behavior upon the samples microstructure.

  20. FMR study of Co-substituted yttrium iron garnet films

    NASA Astrophysics Data System (ADS)

    Jabłoński, R.; Maziewski, A.; Tekielak, M.; Desvignes, J. M.

    1996-07-01

    Ferromagnetic resonance has been studied in Y 3- zCa zFe 5- x-yCo xGe yO 12 films grown on the (001) plane of a GGG substrate. Temperature-induced spin-reorientation phase transitions were observed. On cooling the sample, the easy magnetization axes orientations changed from directions near [111] to [100], and the [001] direction had the lowest energy. The FMR signal was practically non-measurable below 60 and 120 K when the magnetic field was applied along the [110] and [100] axes, respectively.

  1. Structural and magnetic studies of Cr doped nickel ferrite thin films

    NASA Astrophysics Data System (ADS)

    Panwar, Kalpana; Heda, N. L.; Tiwari, Shailja; Bapna, Komal; Choudhary, R. J.; Phase, D. M.; Ahuja, B. L.

    2016-05-01

    We have studied the structural and magnetic properties of Cr doped nickel ferrite thin films deposited on Si (100) and Si (111) using pulsed laser deposition technique. The films were deposited under vacuum and substrate temperature was kept at 700˚C. X-ray diffraction analysis revealed that films on both substrates have single phase cubic spinel structure. However, the film grown on Si (111) shows better crystalline behavior. Fourier transform infrared spectroscopy suggests that films on both substrates have mixed spinel structure. These films show magnetic hysteresis behavior and magnetization value of film on Si (100) is larger than that on Si (111). It turns out that structural and magnetic properties of these two films are correlated.

  2. Study of microstructure and electroluminescence of zinc sulfide thin film

    NASA Astrophysics Data System (ADS)

    Zhao-hong, Liu; Yu-jiang, Wang; Mou-zhi, Chen; Zhen-xiang, Chen; Shu-nong, Sun; Mei-chun, Huang

    1998-03-01

    The electroluminscent zinc sulfide thin film doped with erbium, fabricated by thermal evaporation with two boats, are examined. The surface and internal electronic states of ZnS thin film are measured by means of x-ray diffraction and x-ray photoemission spectroscopy. The information on the relations between electroluminescent characteristics and internal electronic states of the film is obtained. And the effects of the microstructure of thin film doped with rare earth erbium on electroluminescence are discussed as well.

  3. Design of hybrid sol gel films for direct x-ray and electron beam nanopatterning

    NASA Astrophysics Data System (ADS)

    Brusatin, Giovanna; Della Giustina, Gioia; Romanato, Filippo; Guglielmi, Massimo

    2008-04-01

    New epoxy based sol-gel organic inorganic materials, showing lithographic resist-like properties without the addition of any photocatalysts, are presented. To obtain a material sensitive to radiation, specific sol-gel syntheses based on an organically modified alkoxide containing an epoxy ring, 3-glycidoxypropyltrimethoxysilane (GPTMS), have been developed. The synthesis and the patternability of hybrid materials have been obtained controlling the inorganic crosslinking degree and with an almost total absence of organic polymerization. Two examples of directly patternable hybrid films, called GB and GGe, have been synthesized using acidic (GGe) and basic (GB) conditions and obtaining different compositions. After electron beam lithography (EBL) or x-ray synchrotron radiation lithography (XRL) the polymerization of the organic component of the sol-gel film occurs, generating a hardening of the structure after post-exposure baking. The exposed polymerized material becomes insoluble, determining a negative resist-like behaviour of the film: the lithographic process of nanopatterning results from the dissolution of the unexposed areas in proper solvents (developers). Spatial resolution of the order of 200 nm is reported and a contrast of 2.2 is achieved. The novelty of this work is that epoxy based materials, which have enhanced thermomechanical stability with respect to the more usual acrylic based resins, are directly nanopatterned for the first time by electron beam (EB) and/or x-ray beam radiation exposure without the aid of catalysts for polymerization. In contrast to common resists that are sacrificial layers of the fabrication process, direct patternable sol-gel hybrids constitute the final material of the devices. In fact, an example of doping with a light emitting dye is reported together with the achievement of directly patterned structures by EBL and XRL.

  4. Studies of thin films of Ti- Zr -V as non-evaporable getter films prepared by RF sputtering

    SciTech Connect

    Gupta, Nidhi; Jagannath,; Sharma, R. K.; Gadkari, S. C.; Muthe, K. P.; Mukundhan, R.; Gupta, S. K.

    2013-02-05

    Non-Evaporable Getter (NEG) films of the Ti-Zr-V prepared on stainless steel substrates by Radio Frequency sputtering. To observe its getter behavior at the lowest activation temperature, the sample is heated continuously at different temperatures (100 Degree-Sign C, 150 Degree-Sign C, 200 Degree-Sign C and 250 Degree-Sign C) for 2 hours. The changes of the surface chemical composition at different temperaturesare analyzed by using XPS and SEM (Scanning Electron Microscopy) techniques. The volume elemental composition of the film has been measured by energy dispersive X-ray spectroscopy (EDX). The in-situ XPS measurements of the activated getter films show the disappearance of the superficial oxide layer through the variation in the oxygen stoichiometry during thermal activation. Results of these studies show that the deposited films of Ti-Zr-V could be used as NEG to produce extreme high vacuum.

  5. Spectroscopic studies of model polar stratospheric cloud films

    NASA Technical Reports Server (NTRS)

    Tolbert, Margaret A.; Koehler, Birgit G.; Middlebrook, Ann M.

    1993-01-01

    Fourier transform infrared (FTIR) spectroscopy has been used to study nitric-acid/ice films representative of type I polar stratospheric clouds (PSCs). These studies reveal that in addition to amorphous nitric acid/ice mixtures, there are three stable stoichiometric hydrates of nitric acid: nitric-acid monohydrate (NAM), dihydrate (NAD), and trihydrate (NAT). We also observe two distinct crystalline forms of the trihydrate, which we denote alpha- and beta-NAT. These two forms appear to differ in their concentration of crystalline defects, but not in their chemical composition. In addition to probing the composition of type I PSCs, we have also used FTIR spectroscopy to study the interaction of HCl with model PSC films. In this work we find that for HCl pressures in the range 10 exp -5 to 10 exp -7 Torr, HCl is taken up by ice at 155 K to form a thin layer of HCl.6H2O. At 193 K, the uptake of HCl by ice was consistent with less than or equal to monolayer coverage. Uptake of HCl by alpha and beta-NAT at 175 K was also consistent with less than or equal to monolayer coverage.

  6. Raman microprobe spectroscopic studies of solid DNA-CTMA films

    NASA Astrophysics Data System (ADS)

    Yaney, Perry P.; Ahmad, Faizan; Grote, James G.

    2008-08-01

    Extensive studies have been carried out on developing the new biopolymer, deoxyribonucleic acid (DNA) derived from salmon, that has been complexed with a surfactant to make it water insoluble for application to bioelectronic and biophotonic devices. One of the key issues associated with the properties and behavior of solid films of this material is the extreme size of the >8 MDa molecular weight of the virgin, as-received material. Reduction of this molecular weight by factors of up to 40 is achieved by high power sonication. To support the various measurements that have been made to confirm that the sonicated material is still double strand DNA and to look for other effects of sonication, Raman studies were carried out to compare the spectra over a wide range of molecular weights and to develop baseline data that can be used in intercolation studies where various dopants are added to change the electrical, mechanical or optical properties. Raman microprobe spectra from solid, dry thin films of DNA with molecular weights ranging from 200 kDa to >8 MDa complexed with cetyltrimethyl-ammonium chloride (CTMA) are reported and compared to the as-received spectrum and to published DNA spectra in aqueous solutions. In addition, microscopy and measurements on macro-molecular structures of DNA-CTMA are reported.

  7. Moving Pictures: An Annotated Guide to Selected Film Literature With Suggestions for the Study of Film.

    ERIC Educational Resources Information Center

    Sheahan, Eileen

    Intended as a guide for research in the literature of film, this book lists publications that range from early film writings to books published through mid-1977. Entries are listed alphabetically by author or by title, and are numbered sequentially within the following sections: guides and handbooks, dictionaries and encyclopedias, annuals and…

  8. Study of the photovoltaic effect in thin film barium titanate

    NASA Technical Reports Server (NTRS)

    Grannemann, W. W.; Dharmadhikari, V. S.

    1981-01-01

    The photoelectric effect in structures consisting of metal deposited barium titanate film silicon is described. A radio frequency sputtering technique is used to deposit ferroelectric barium titantate films on silicon and quartz. Film properties are measured and correlated with the photoelectric effect characteristics of the films. It was found that to obtain good quality pin hole free films, it is necessary to reduce the substrate temperature during the last part of the deposition. The switching ability of the device with internal applied voltage is improved when applied with a ferroelectric memory device.

  9. Phase separation in antisymmetric films: A molecular dynamics study

    SciTech Connect

    Krishnan, Raishma; Puri, Sanjay; Jaiswal, Prabhat K.

    2013-11-07

    We have used molecular dynamics (MD) simulations to study phase-separation kinetics in a binary fluid mixture (AB) confined in an antisymmetric thin film. One surface of the film (located at z = 0) attracts the A-atoms, and the other surface (located at z = D) attracts the B-atoms. We study the kinetic processes which lead to the formation of equilibrium morphologies subsequent to a deep quench below the miscibility gap. In the initial stages, one observes the formation of a layered structure, consisting of an A-rich layer followed by a B-rich layer at z = 0; and an analogous structure at z = D. This multi-layered morphology is time-dependent and propagates into the bulk, though it may break up into a laterally inhomogeneous structure at a later stage. We characterize the evolution morphologies via laterally averaged order parameter profiles; the growth laws for wetting-layer kinetics and layer-wise length scales; and the scaling properties of layer-wise correlation functions.

  10. Formation of continuous metallic film on quartz studied by noncontact resonant ultrasound spectroscopy

    SciTech Connect

    Nakamura, N. Yoshimura, N.; Ogi, H.; Hirao, M.

    2015-08-28

    Dynamics of continuous film formation of metallic films on quartz substrates is studied using an electrodeless resonance method. Bare quartz is used as a substrate, and a metallic film is deposited on it. We use antenna transmission technique to measure the evolution of resonance frequencies and internal friction of the substrate during and after deposition, and the morphological transition between discontinuous islands and a continuous film is detected. By comparison with atomic force microscopy images, we confirm that the frequency drop and the internal-friction peak that appear during deposition indicate this transition. We also find that Pt film shows unexpected morphology change after deposition.

  11. Center for Thin-Film Studies. Annual report, 1 October 1986-1 October 1987

    SciTech Connect

    Shannon, R.P.; Gibson, U.J.

    1987-11-15

    This report covers the first year of operation of the URI Thin Film Center (TFC), and describes a diverse array of studies on thin-film materials, substrates, and their processing and analysis. Individual efforts are highlighted in sections on nucleation studies, ion-assisted deposition, Rutherford backscattering spectrometry, Brillouin scattering, a continuum theory of the evolution of structure in thin films, a study of polishing parameters relevant to the preparation of substrates, and the setup of a characterization facility for the Center.

  12. Film and Language Learning in Victorian Schools: A Study of the 2009 Next Gen Program of the "Melbourne International Film Festival"

    ERIC Educational Resources Information Center

    Lo Bianco, Hana

    2010-01-01

    This article investigates the role of film in language education based on a study of the 2009 "Melbourne International Film Festival" (MIFF). It is structured around a literature review and results from surveys of students and teachers who participated in the young people's section of the program, Next Gen. The article argues that film can provide…

  13. Fibronectin Terminated Multilayer Films: Protein Adsorption and Cell Attachment Studies

    PubMed Central

    Wittmer, Corinne R.; Phelps, Jennifer A.; Saltzman, W. Mark; Van Tassel, Paul R.

    2006-01-01

    Electrostatically driven layer-by-layer (LbL) assembly is a simple and robust method for producing structurally tailored thin film biomaterials, of thickness ca. 10 nanometers, containing biofunctional ligands. We investigate the LbL formation of multilayer films composed of polymers of biological origin (poly(L-lysine) (PLL) and dextran sulfate (DS)), the adsorption of fibronectin (Fn) - a matrix protein known to promote cell adhesion - onto these films, and the subsequent spreading behavior of human umbilical vein endothelial cells (HUVEC). We employ optical waveguide lightmode spectroscopy (OWLS) and quartz crystal microgravimetry with dissipation (QCMD) to characterize multilayer assembly in situ, and find adsorbed Fn mass on PLL terminated films to exceed that on DS terminated films by 40%, correlating with the positive charge and lower degree of hydration of PLL terminated films. The extent and initial rate of Fn adsorption to both PLL and DS terminated films exceed those onto the bare substrate, indicating the important role of electrostatic complexation between negatively charged protein and positively charged PLL at or near the film surface. We use phase contrast optical microscopy to investigate the time dependent morphological changes of HUVEC as a function of layer number, charge of terminal layer, and the presence of Fn. We observe HUVEC to attach, spread, and lose circularity on all surfaces. (Positively charged) PLL terminated films exhibit a greater extent of cell spreading than do (negatively charged) DS terminated films, and spreading is enhanced while circularity loss is suppressed by the presence of adsorbed Fn. The number of layers plays a significant role only for DS terminated films with Fn, where spreading on a bilayer greatly exceeds that on a multilayer, and PLL terminated films without Fn, where initial spreading is significantly higher on a monolayer. We observe initial cell spreading to be followed by retraction (i.e. decreased cell

  14. Microhardness studies on thin carbon films grown on P-type, (100) silicon

    NASA Technical Reports Server (NTRS)

    Kolecki, J. C.

    1982-01-01

    A program to grow thin carbon films and investigate their physical and electrical properties is described. Characteristics of films grown by rf sputtering and vacuum arc deposition on p type, (100) silicon wafers are presented. Microhardness data were obtained from both the films and the silicon via the Vickers diamond indentation technique. These data show that the films are always harder than the silicon, even when the films are thin (of the order of 1000 A). Vacuum arc films were found to contain black carbon inclusions of the order of a few microns in size, and clusters of inclusions of the order of tens of microns. Transmission electron diffraction showed that the films being studied were amorphous in structure.

  15. Study of photoluminescence properties of thin films DR1

    NASA Astrophysics Data System (ADS)

    Herman, Ulya, Naily

    2015-09-01

    Fabrication of thin films DR1 have been carried out by the EFA-PDF (Electric Field-Assisted Physical Vapor Deposition) method to obtain films with parallel dipole arrangement. Molecular deposition process is performed by applying an electric field that is placed between the substrate ITO (Indium Tin Oxide) and copper mesh. The resulting films were characterized by using a spectrofluorometer. Analysis of the emission spectrum, indicate that DR1 molecules in the film oriented perpendicular to the substrate and arranged in parallel order (H-aggregate). As an effect, the peak of the emission spectrum appears stronger along with the increase of electric field strength.

  16. Study of photoluminescence properties of thin films DR1

    SciTech Connect

    Herman, Ulya, Naily

    2015-09-30

    Fabrication of thin films DR1 have been carried out by the EFA-PDF (Electric Field-Assisted Physical Vapor Deposition) method to obtain films with parallel dipole arrangement. Molecular deposition process is performed by applying an electric field that is placed between the substrate ITO (Indium Tin Oxide) and copper mesh. The resulting films were characterized by using a spectrofluorometer. Analysis of the emission spectrum, indicate that DR1 molecules in the film oriented perpendicular to the substrate and arranged in parallel order (H-aggregate). As an effect, the peak of the emission spectrum appears stronger along with the increase of electric field strength.

  17. Study of indium tin oxide films exposed to atomic axygen

    NASA Technical Reports Server (NTRS)

    Snyder, Paul G.; De, Bhola N.; Woollam, John A.; Coutts, T. J.; Li, X.

    1989-01-01

    A qualitative simulation of the effects of atomic oxygen has been conducted on indium tin oxide (ITO) films prepared by dc sputtering onto room-temperature substrates, by exposing them to an RF-excited oxygen plasma and characterizing the resulting changes in optical, electrical, and structural properties as functions of exposure time with ellipsometry, spectrophotometry, resistivity, and X-ray measurements. While the films thus exposed exhibit reduced resistivity and optical transmission; both of these effects, as well as partial crystallization of the films, may be due to sample heating by the plasma. Film resistivity is found to stabilize after a period of exposure.

  18. Comparison of diagnostic accuracy of plain film radiographs between original film and smartphone capture: a pilot study.

    PubMed

    Licurse, Mindy Y; Kim, Sung H; Kim, Woojin; Ruutiainen, Alexander T; Cook, Tessa S

    2015-12-01

    The use of mobile devices for medical image capture has become increasingly popular given the widespread use of smartphone cameras. Prior studies have generally compared mobile phone capture images to digitized images. However, many underserved and rural areas without picture archiving and communication systems (PACS) still depend greatly on the use of film radiographs. Additionally, there is a scarcity of specialty-trained or formally licensed radiologists in many of these regions. Subsequently, there is great potential for the use of smartphone capture of plain radiograph films which would allow for increased access to economical and efficient consultation from board-certified radiologists abroad. The present study addresses the ability to diagnose a subset of radiographic findings identified on both the original film radiograph and the captured camera phone image. PMID:25840654

  19. X-Ray and Optical Studies of Thin Organic Films

    NASA Astrophysics Data System (ADS)

    Foster, William Joseph, Jr.

    1995-01-01

    In order to quantitatively understand the fundamental statistical physics of Langmuir monolayers (LMs) it is essential that their properties be measured under equilibrium conditions. In order to address this issue, the phase diagrams of relaxed films of doeicosanoic acid and methyl eicosanoate were mapped out over the temperature range of 5.5^circ to 26 ^circC. In contrast to the prevailing technique in which isotherms are taken at a constant rate of compression, isotherms in this study were taken through a series of incremental compressions, separated by variable waiting periods that allowed the monolayer to relax to a steady state. X-ray diffraction, Brewster angle microscopy, and surface pressure measurements at each area were interpreted to characterize the structure of the phases of a relaxed LM of methyl eicosanoate. Below 12^circ C and 2.25 dynes/cm the I(L_2^ {''}) phase, an orthorhombic structure with tilt toward nearest neighbor was observed. Between 12^circ and 22^ circC and below 8 dynes/cm the F(L _2^') phase, with tilt toward next nearest neighbor and an orthorhombic structure was seen. Above 22^circC the Ov phase, with tilt toward nearest neighbor and a hexagonal structure was seen. At higher pressures, the U ^'(CS)/U(S)/R(LS) sequence of phases, typical of most saturated alkane systems, was detected. In order to better understand issues of equilibrium and relaxation for LMs of the fatty acids and to compare our results to previous "fast" measurements, a detailed study of relaxed films of doeicosanoic acid was conducted. Both relaxation isotherms and isochores were performed simultaneously with x-ray diffraction measurements. It was found that, despite uncertainty in the macroscopic trough area per molecule due to collapse of the film, a physically useful phase diagram could be constructed in terms of the microscopic area per molecule, derived from diffraction measurements. In addition, by using a two-dimensional analog of the Clausius -Clapeyron

  20. Initial thin film penetration studies at the Colorado Center for Lunar Dust and Atmospheric Studies

    NASA Astrophysics Data System (ADS)

    Shu, A. J.; Collette, A.; Drake, K. J.; Gruen, E.; Horanyi, M.; Kempf, S.; Munsat, T.; Northway, P.; Robertson, S. H.; Srama, R.; Sternovsky, Z.; Thomas, E.; Colorado CenterLunar Dust; Atmospheric Studies

    2011-12-01

    Initial studies of damage caused by hypervelocity impacts of various micrometeorite materials into a range of targets are being performed at the Colorado Center for Lunar Dust and Atmospheric Studies (CCLDAS). Cratering studies are initially focused on polyvinylidene fluoride (PVDF) films in order to characterize the crater dependencies on impactor mass, size, and speed, and to better understand its capabilities as a dust detector. Additional cratering studies include optical glass, and geological samples as targets. These studies will lead to a better understanding of damage to spacecraft windows and instruments, and space weathering on airless bodies. In parallel, penetration studies will be conducted to determine how hole sizes in thin film materials depend on the properties of the film and the projectile. These thin film penetration studies will be critical to the design of dust detectors similar to that used on NASA's Stardust and New Horizons spacecraft, and in the design of solar sails. Thin film detectors can also be used to characterize beam profiles of laboratory dust accelerators. These studies are being performed at the 3MV hypervelocity dust accelerator at CCLDAS. The facility can accelerate dust particles up to 10's of km/s with user control over the velocity and mass ranges of particles reaching the target chamber. Complementary studies will be conducted at the Johnson Space Center Light Gas Gun using the same target and particle properties. These parallel studies will allow us to cover an extended range of acceleration parameters as well as better understand the similarities and differences between electrostatic accelerators and light gas guns.

  1. Contact angle and film pressure: study of a talc surface.

    PubMed

    Douillard, J M; Zajac, J; Malandrini, H; Clauss, F

    2002-11-15

    Talc samples in both sheet and powder form are studied by adsorption calorimetry and adsorption isotherm techniques. A model is used to determine the solid surface energy, the solid surface tension and the dispersive, acidic, and basic components of these terms. These results are introduced in an approximate equation relating adsorption to contact angle data. Experimental contact angles are in correct agreement with this approach. The Neumann equation of state is used to fit the data and discussed. It appears as a numerical form of the general equation taking into account gas adsorption and film pressure. Behaviors of talc in contact with liquids do not appear very different whether the solid is in sheet or powder form. PMID:12505082

  2. Theoretical and material studies of thin-film electroluminescent devices

    NASA Technical Reports Server (NTRS)

    Summers, C. J.

    1989-01-01

    Thin-film electroluminescent (TFEL) devices are studied for a possible means of achieving a high resolution, light weight, compact video display panel for computer terminals or television screens. The performance of TFEL devices depends upon the probability of an electron impact exciting a luminescent center which in turn depends upon the density of centers present in the semiconductor layer, the possibility of an electron achieving the impact excitation threshold energy, and the collision cross section itself. Efficiency of such a device is presently very poor. It can best be improved by increasing the number of hot electrons capable of impact exciting a center. Hot electron distributions and a method for increasing the efficiency and brightness of TFEL devices (with the additional advantage of low voltage direct current operation) are investigated.

  3. Raman studies of lattice dynamics and phase transitions in barium strontium titanate thin films

    NASA Astrophysics Data System (ADS)

    Tenne, D. A.; Xi, X. X.; Li, Y. L.; Chen, L. Q.; Soukiassian, A.; Schlom, D. G.; Taylor, T. R.; Hansen, P. J.; Speck, J. S.; York, R. A.; Choosuwan, H.; He, Qi; Guo, R.; Bhalla, A. S.

    2004-03-01

    The lattice dynamics and phase transitions in Ba_xSr_1-xTiO3 (BST) thin films single crystals were studied by Raman spectroscopy. Our studies revealed essential differences in the lattice dynamical properties Ba_xSr_1-xTiO3 films and single crystals: Forbidden first order Raman scattering in BST films well above the bulk phase transition temperature where the crystals show the second order Raman features only; hardening of the soft phonon modes in films compared to crystals; significantly larger range of the E soft mode overdamping in films, which supposes an additional damping mechanism in films, not present in crystals. Lattice dynamics behavior in the BST films is similar to that of relaxor ferroelectrics. Analogously to the relaxors, the existence of polar nanoregions in the films at the above the bulk Curie-Weiss temperature explains the specific lattice-dynamical properties of BST films. The effect of strain on the phase transitions in Ba_xSr_1-xTiO3 thin films will also be discussed. In polycrystalline BST films grown on the substrates providing a systematic change in the thermal strain, it was found that the out-of-plane polarization is likely locked during the growth and cooling processes. This leads to a decreasing of the Tc with increasing tensile strain. In the epitaxial BaTiO3 films, the Raman studies show that the tetragonal-orthorhombic-rhombohedral phase transitions, characteristic of bulk BaTiO_3, are completely absent due to the presence of tensile strain. This is confirmed by a phase diagram for BaTiO3 film obtained from thermodynamic phase-field calculations.

  4. Comparative Study of Cu Films Prepared by DC, High-Power Pulsed and Burst Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Solovyev, A. A.; Oskirko, V. O.; Semenov, V. A.; Oskomov, K. V.; Rabotkin, S. V.

    2016-05-01

    A comparative study of deposition rate, adhesion, structural and electrical properties of nanocrystalline copper thin films deposited using direct current magnetron sputtering (DCMS) and different regimes of high power pulsed magnetron sputtering is presented. High-power impulse magnetron sputtering (HIPIMS) and burst regime (pulse packages) of magnetron sputtering are investigated. The ion and atomic flows toward the growing film during magnetron sputtering of a Cu target are determined. X-ray diffraction, scanning electron microscopy and atomic force microscopy were used to observe the structural characterization of the films. The resistivity of the films was measured using four-point probe technique. In all sputtering regimes, Cu films have mixture crystalline orientations of [111], [200], [311] and [220] in the direction of the film growth. As peak power density in studied deposition regimes was different in order of magnitude (from 15 W/cm2 in DC regime to 3700 W/cm2 in HIPIMS), film properties were also greatly different. DCMS Cu films exhibit a porous columnar grain structure. In contrast, HIPIMS Cu films have a slightly columnar and denser composition. Cu films deposited using burst regimes at peak power density of 415 W cm-2 and ion-to-atom ratio of about 5 have the densest composition and smallest electrical resistance.

  5. Comparative Study of Cu Films Prepared by DC, High-Power Pulsed and Burst Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Solovyev, A. A.; Oskirko, V. O.; Semenov, V. A.; Oskomov, K. V.; Rabotkin, S. V.

    2016-08-01

    A comparative study of deposition rate, adhesion, structural and electrical properties of nanocrystalline copper thin films deposited using direct current magnetron sputtering (DCMS) and different regimes of high power pulsed magnetron sputtering is presented. High-power impulse magnetron sputtering (HIPIMS) and burst regime (pulse packages) of magnetron sputtering are investigated. The ion and atomic flows toward the growing film during magnetron sputtering of a Cu target are determined. X-ray diffraction, scanning electron microscopy and atomic force microscopy were used to observe the structural characterization of the films. The resistivity of the films was measured using four-point probe technique. In all sputtering regimes, Cu films have mixture crystalline orientations of [111], [200], [311] and [220] in the direction of the film growth. As peak power density in studied deposition regimes was different in order of magnitude (from 15 W/cm2 in DC regime to 3700 W/cm2 in HIPIMS), film properties were also greatly different. DCMS Cu films exhibit a porous columnar grain structure. In contrast, HIPIMS Cu films have a slightly columnar and denser composition. Cu films deposited using burst regimes at peak power density of 415 W cm-2 and ion-to-atom ratio of about 5 have the densest composition and smallest electrical resistance.

  6. a Study of the Morphology of Pmda-Oda Polyimide Films.

    NASA Astrophysics Data System (ADS)

    Stone, Craig Douglas

    This research examines how the morphology of PMDA -ODA polyimide films varies as a condition of production and post-imidization treatments. These films were produced using chemical and thermal imidization techniques. The PMDA-ODA films were studied using four different techniques. Optical anisotropy, density and wide and small-angle x-ray scattering measurements were made. Wide-angle x-ray diffraction was used to examine the short-range nature of the ordering while small-angle x-ray scattering was used for long-period spacing and void studies. This research shows that the morphology of PMDA -ODA films depends on the method of imidization. The chemically imidized PMDA-ODA varies from the thermally imidized films. The chemically imidized films are more in-plane and out-of -plane anisotropic which is a result of the lateral stress applied to the film during imidization. These commercially prepared films (Du Pont Kapton^circler) are cast on a high-speed conveyor which applies the stress to the polyamic acid precursor. The thermally imidized films, in contrast, are cast onto glass plates which does not subject them to the same degree of stress. The chemically imidized films also had larger void sizes ( ~35 A compared to ~ 25A) and smaller void fractions. The stresses applied to Kapton^circler resulted in the enlargement of the voids during imidization. For Kapton^circler, the lower void fractions in the thinner films resulted both from the thickness of the film which allowed voids to escape more easily and the larger ordered domains in these samples. The PMDA-ODA films were also thermally treated and soaked in water. The water immersion studies helped to prove the existence of the voids within the films. Although most of the thermal treatments had some effect on the polyimide films, these effects are small at lower temperatures. Upon annealing at temperatures of 450 ^circC, this film experienced a major change in morphology. In addition to degradation of the material

  7. Growth and study of antimony selenide island films

    NASA Astrophysics Data System (ADS)

    Kushkhov, A. R.; Gaev, D. S.; Rabinovich, O. I.; Stolyarov, A. G.

    2013-03-01

    Nanosized Sb2Se3 island films are prepared by the incongruent evaporation of Sb1 - x Se x ( x = 0.9 at fractions) thin films. The surface morphology of the structures is investigated by optical and atomic force microscopy (AFM). It is shown that an increase in the evaporation temperature leads to a decrease in the surface density of islands.

  8. "Making the Devil Useful": Film Studies in the English Curriculum.

    ERIC Educational Resources Information Center

    Bruder, Carolyn R.

    Film is not often taught for itself and by itself; it is too often viewed as the handmaiden of literature. More often than not it is taught in English departments because: (1) like novels, poems, plays and philosophical arguments, it is a humanistic text; (2) film writers and directors have historically turned to literary texts as their source…

  9. Slow-Positron Generator For Studying Polymer Films

    NASA Technical Reports Server (NTRS)

    Singh, Jag J.; St. Clair, Terry L.; Eftekhari, Abe

    1992-01-01

    Aspects of molecular structures probed by positron-annihilation spectroscopy (PAS). Slow-positron-beam generator suitable for PAS measurements in thin polymer films. Includes Na22 source of positrons and two moderators made of well-annealed tungsten foil. With proper choice of voltage, positrons emitted by inward-facing surfaces of moderators made to stop in polymer films tested.

  10. Some studies on successive ionic layer adsorption and reaction (SILAR) grown indium sulphide thin films

    SciTech Connect

    Pathan, H.M.; Lokhande, C.D. . E-mail: l_chandrakant@yahoo.com; Kulkarni, S.S.; Amalnerkar, D.P.; Seth, T.; Han, Sung-Hwan . E-mail: shhan@hanyang.ac.kr

    2005-06-15

    Indium sulphide (In{sub 2}S{sub 3}) thin films were grown on amorphous glass substrate by the successive ionic layer adsorption and reaction (SILAR) method. X-ray diffraction, optical absorption, scanning electron microscopy (SEM) and Rutherford back scattering (RBS) were applied to study the structural, optical, surface morphological and compositional properties of the indium sulphide thin films. Utilization of triethanolamine and hydrazine hydrate complexed indium sulphate and sodium sulphide as precursors resulted in nanocrystalline In{sub 2}S{sub 3} thin film. The optical band gap was found to be 2.7 eV. The film appeared to be smooth and homogeneous from SEM study.

  11. Nanoindentation Studies Of Hard Nanocomposite Ti-B-N Thin Films

    SciTech Connect

    Rupa, P. Karuna Purnapu; Chakraborty, P. C.; Mishra, Suman Kumari

    2011-12-12

    Titanium boron nitride (Ti-B-N) films were deposited by reactive magnetron sputtering using single Titanium diboride (TiB{sub 2}) target in different Ar-N{sub 2} gas mixtures. The influence of N{sub 2}:Ar ratio on the microstructure and mechanical properties of the deposited films have been investigated. Atomic force microscopy analysis indicated the grain size decreases with incorporation of nitrogen in the films. Nanoindentation studies have shown the hardness decreases with nitrogen incorporation.

  12. Tribological studies of amorphous hydrogenated carbon films in a vacuum, spacelike environment

    NASA Technical Reports Server (NTRS)

    Miyoshi, Kazuhisa

    1991-01-01

    Recent work on the adhesion and friction properties of plasma-deposited amorphous hydrogenated carbon films and their dependence on preparation conditions are reviewed. The results of the study indicate that plasma deposition enables one to deposit a variety of amorphous hydrogenated carbon (a-C:H) exhibiting diamondlike friction behavior. The plasma-deposited a-C:H films can be effectively used as hard lubricating films on ceramic materials such as silicon nitride in vacuum.

  13. X-ray diffraction studies of sprayed SnO 2: Sb films

    NASA Astrophysics Data System (ADS)

    Goyal, D. J.; Agashe, Chitra; Takwale, M. G.; Bhide, V. G.

    1993-06-01

    Antimony-doped tin oxide films were deposited by spray pyrolysis on Corning 7059 substrates. The structural and electrical properties of the films deposited with different doping levels were studied. Relative variations in the structural properties were explained on the basis of structure factor calculations. The results show that the incorporation of antimony atoms takes place only at substitutional sites. As expected, the substitutional replacement of tin by antimony atoms increased appreciably the free carrier density of the film.

  14. Dynamic study of nanodroplet nucleation and growth on self-supported nanothick liquid films.

    PubMed

    Barkay, Z

    2010-12-01

    The dynamics of water condensation on self-supported thin films was studied at the nanoscale using transmitted electrons in an environmental scanning electron microscope. The initial stages of nucleation and growth over nanothick water films have been investigated. Irregularities at the water-film boundaries constituted nucleation sites for asymmetric dropwise and filmwise condensation. Nanodroplet growth was associated with center of mass movement, and the dynamic growth power law dependence was explored for the nanoscale. PMID:21073155

  15. Synthesis, characterization and ellipsometric study of ultrasonically sprayed Co3O4 films

    NASA Astrophysics Data System (ADS)

    Gençyılmaz, O.; Taşköprü, T.; Atay, F.; Akyüz, İ.

    2015-10-01

    In the present study, cobalt oxide (Co3O4) films were produced using ultrasonic spray pyrolysis technique onto the glass substrate at different temperatures (200-250-300-350 °C). The effect of substrate temperature on the structural, optical, surface and electrical properties of Co3O4 films was reported. Thickness, refractive index and extinction coefficient of the films were determined by spectroscopic ellipsometry, and X-ray diffraction analyses revealed that Co3O4 films were polycrystalline fcc structure and the substrate temperature significantly improved the crystal structure of Co3O4 films. The films deposited at 350 °C substrate temperature showed the best structural quality. Transmittance, absorbance and reflectance spectra were taken by means of UV-Vis spectrophotometer, and optical band gap values were calculated using optical method. Surface images and roughness values of the films were taken by atomic force microscopy to see the effect of deposition temperature on surface properties. The resistivity of the films slightly decreases with increase in the substrate temperature from 1.08 × 104 to 1.46 × 102 Ω cm. Finally, ultrasonic spray pyrolysis technique allowed production of Co3O4 films, which are alternative metal oxide film for technological applications, at low substrate temperature.

  16. A study on the wet etching behavior of AZO (ZnO:Al) transparent conducting film

    NASA Astrophysics Data System (ADS)

    Lin, Y. C.; Jian, Y. C.; Jiang, J. H.

    2008-02-01

    This paper studies the wet etching behavior of AZO (ZnO:Al) transparent conducting film with tetramethylammonium hydroxide (TMAH). The optimum optoelectronic film is prepared first using designated RF power, film thickness and controlled annealing heat treatment parameters. The AZO film is then etched using TMAH etchant and AZ4620 photoresist with controlled etchant concentration and temperature to examine the etching process effect on the AZO film optoelectronic properties. The experimental results show TMAH:H 2O = 2.38:97.62 under 45 °C at the average etch rate of 22 nm/min as the preferred parameters. The activation energy drops as the TMAH concentration rises, while the etch rate increases along with the increase in TMAH concentration and temperature. After lithography, etching and photoresist removal, the conductivity of AZO film dramatically drops from 2.4 × 10 -3 Ω cm to 3.0 × 10 -3 Ω cm, while its transmittance decreases from 89% to 83%. This is due to the poor chemical stability of AZO film against AZ4620 photoresist, leading to an increase in surface roughness. In the photoresist postbaking process, carbon atoms diffused within the AZO film produce poor crystallinity. The slight decreases in zinc and aluminum in the thin film causes a carrier concentration change, which affect the AZO film optoelectronic properties.

  17. Anomalous Hall effect studies on Tb-Fe thin films

    NASA Astrophysics Data System (ADS)

    Rajasekhar, P.; Deepak Kumar, K.; Markandeyulu, G.

    2016-08-01

    Tbx Fe100-x (with x=11, 25, 31 and 44) thin films were prepared with the substrates kept at a temperature of 300 °C and the Hall resistivities and electrical resistivities were investigated in the temperature range 25-300 K. The sign of Hall resistivity is found to change from positive for x=31 to negative for x=44 film at temperatures 25 K and 300 K, reflecting the compensation of Tb and Fe magnetic moments between these two compositions. Perpendicular magnetic anisotropy was observed in the films of x=25 and 31 at 25 K as well as at 300 K. The Hall resistivity is seen to increase for the films of x=11 and 31 with increasing temperature, while it decreases for the films of x=25 and 44 with increasing temperature. The temperature coefficients of electrical resistivities of these films are seen to be positive. The presence of perpendicular magnetic anisotropy (refers to magnetic anisotropy, in this paper) in the temperature range 25-300 K in Tb25Fe75 and Tb31Fe69 and their metallic nature are indicators that the Tb-Fe films deposited at higher temperatures are more suitable for magneto optic data storage applications than their amorphous counterparts, due to the stability of the former.

  18. A comparative study: Effect of plasma on V2O5 nanostructured thin films

    NASA Astrophysics Data System (ADS)

    Singh, Megha; Kumar, Prabhat; Sharma, Rabindar K.; Reddy, G. B.

    2016-05-01

    Vanadium pentoxide nanostructured thin films (NSTs) have been studied to analyze the effect of plasma on nanostructures grown and morphology of films deposited using sublimation process. Nanostructured thin films were deposited on glass substrates, one in presence of oxygen plasma and other in oxygen environment (absence of plasma). Films were characterized using XRD, Raman spectroscopy, SEM and HRTEM. XRD studies revealed α-V2O5 films (orthorhombic phase) with good crystallinity. However, film deposited in presence of plasma have higher peak intensities as compared to those deposited in absence of plasma. Raman studies also support these finding following same trends of considerable increase in intensity in case of film deposited in presence of plasma. SEM micrographs makes the difference more visible, as film deposited in plasma have well defined plate like structures whereas other film have not-clearly-defined petal-like structures. HRTEM results show orthorhombic phase with 0.39 nm interplanar spacing, as reported by XRD. Results are hereby in good agreement with each other.

  19. Study of CVD SiC thin film for space mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhan; Zhang, Yumin; Han, Jiecai; He, Xiaodong

    2006-01-01

    The performance of space mirror lied on the properties of the mirror surface material to a great extent. In this paper, the silicon carbide thin film deposited on reaction-bonded silicon carbide (RBSC) space mirror blank was produced by Chemical Vapor Deposition (CVD) process. Some mechanical and physical properties of the SiC thin film were tested because they were important to study ability to work of space mirror. The result of XRD phase analysis indicated that the component of the SiC thin film was β-SiC. The micro hardness of the film was tested. The thickness of SiC thin film was tested using needle touch contour graph. The results showed that the thickness of SiC film was about 20 μm and film was even in the macro scope. The adhesion strength of SiC thin film and RBSC substrate was tested by scratch method and the results showed that was excellent. The residual stress of SiC thin film was tested by X-ray, at the same time; the origin of residual stress and the calculation of thermal stress were discussed. In the room temperature, the residual stress of the SiC film was compressive. After precision grinding, the surface topography and roughness of the SiC thin film was tested by Atomic Force Microscope (AFM). The results showed that the surface of SiC thin film had extremely low surface roughness and high surface form accuracy. The thermal shock resistance of SiC film was fine by tested.

  20. Study for Electrode Metals on Taste Sensor with LB film

    NASA Astrophysics Data System (ADS)

    Yokoya, Takahiro; Hirata, Takamichi; Akiya, Masahiro

    In this paper, sensor responses with only metal electrode as Au, Cr, Ti and more with LB film were described. LB film material was the Dioctadecyldimethylammonium bromide combined by PVSK as an underlayer. To detect five basic taste substances, sensor parameters were defined as maximum voltage change and response time. Response time for sourness and umami with Ti and Cr evaporated metal electrode was larger than that of usual Au electrode. LB film effect was finally found to increase response time for five basic taste materials.

  1. XRay Study of Transfer Printed Pentacene Thin Films

    SciTech Connect

    Shao, Y.; Solin, S. A.; Hines, D. R.; Williams, E. D.

    2007-04-10

    We investigated the structural properties and transfer properties of pentacene thin films fabricated by thermal deposition and transfer printing onto SiO2 and plastic substrates, respectively. The dependence of the crystallite size on the printing time, temperature and pressure were measured. The increases of crystalline size were observed when pentacene thin films were printed under specific conditions, e.g. 120 deg. C and 600 psi and can be correlated with the improvement of the field effect mobility of pentacene thin-film transistors.

  2. Vibrational properties of epitaxial Bi4Te3 films as studied by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Xu, Hao; Song, Yuxin; Pan, Wenwu; Chen, Qimiao; Wu, Xiaoyan; Lu, Pengfei; Gong, Qian; Wang, Shumin

    2015-08-01

    Bi4Te3, as one of the phases of the binary Bi-Te system, shares many similarities with Bi2Te3, which is known as a topological insulator and thermoelectric material. We report the micro-Raman spectroscopy study of 50 nm Bi4Te3 films on Si substrates prepared by molecular beam epitaxy. Raman spectra of Bi4Te3 films completely resolve the six predicted Raman-active phonon modes for the first time. Structural features and Raman tensors of Bi4Te3 films are introduced. According to the wavenumbers and assignments of the six eigenpeaks in the Raman spectra of Bi4Te3 films, it is found that the Raman-active phonon oscillations in Bi4Te3 films exhibit the vibrational properties of those in both Bi and Bi2Te3 films.

  3. Photoconductivity studies on amorphous and crystalline TiO2 films doped with gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Valverde-Aguilar, G.; García-Macedo, J. A.; Rentería-Tapia, V.; Aguilar-Franco, M.

    2011-06-01

    In this work, amorphous and crystalline TiO2 films were synthesized by the sol-gel process at room temperature. The TiO2 films were doped with gold nanoparticles. The films were spin-coated on glass wafers. The crystalline samples were annealed at 100°C for 30 minutes and sintered at 520°C for 2 h. All films were characterized using X-ray diffraction, transmission electronic microscopy and UV-Vis absorption spectroscopy. Two crystalline phases, anatase and rutile, were formed in the matrix TiO2 and TiO2/Au. An absorption peak was located at 570 nm (amorphous) and 645 nm (anatase). Photoconductivity studies were performed on these films. The experimental data were fitted with straight lines at darkness and under illumination at 515 nm and 645 nm. This indicates an ohmic behavior. Crystalline TiO2/Au films are more photoconductive than the amorphous ones.

  4. The study of MgB2/BN/MgB2 trilayer films

    NASA Astrophysics Data System (ADS)

    Hu, Hui; Feng, Qingrong; Wang, Yue; Zhang, Yan

    2015-12-01

    MgB2/BN/MgB2 trilayer films have been fabricated by using hybrid physical-chemical vapor deposition (HPCVD) method for the MgB2 layers and chemical vapor deposition (CVD) method for the BN layers in the same reactor. The films are studied by X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD) and magnetization measurements. These test outcomes indicate the trilayer films are grown without deteriorating the superconductivity of MgB2 films. Our results show that it is feasible to grow MgB2/BN/MgB2 trilayer films in the same reactor sequentially, which has the advantage of reducing contamination during the growth. This therefore opens the door for fabricating all-MgB2 Josephson junctions by using the BN film as the insulating layer.

  5. Microstructure investigation and magnetic study of permalloy thin films grown by thermal evaporation

    NASA Astrophysics Data System (ADS)

    Lamrani, Sabrina; Guittoum, Abderrahim; Schäfer, Rudolf; Pofahl, Stefan; Neu, Volker; Hemmous, Messaoud; Benbrahim, Nassima

    2016-06-01

    We study the effect of thickness on the structural and magnetic properties of permalloy thin films, evaporated on glass substrate. The films thicknesses range from 16 to 90 nm. From X-ray diffraction spectra analysis, we show that the thinner films present a "1,1,1" preferred orientation. However, the thicker films exhibit a random orientation. The grains size increases and the lattice parameter decreases with increasing thickness. The magnetic force microscopy observations display cross-tie walls features only for the two thicker films (60 and 90 nm thick films). The magnetic microstructure, carried out by Kerr microscopy technique, shows the presence of magnetic domains changing with the direction of applied magnetic field. The coercive field, Hc, was found to decrease from 6.5 for 16 to 1.75 Oe for 90 nm. All these results will be discussed and correlated.

  6. Crystal structure of thin oxide films grown on Zr-Nb alloys studied by RHEED

    NASA Astrophysics Data System (ADS)

    Khatamian, D.; Lalonde, S. D.

    1997-05-01

    The highly surface sensitive reflection high energy electron diffraction (RHEED) technique was used to determine thecrystal structure of oxide films grown on Zr-Nb alloys in air up to 673 K. The results show that the oxide films grown on Zr-2.5 wt% Nb(α-Zr + β-Zr) have a mixture of nearly-cubic-tetragona and monoclinic structures for films of 200 nm thick or less and that the outer layers of films thicker than 800 nm only have the monoclinic crystal structure. However, oxide films grown on Zr-20 wt% Nb (β-Zr) have a stabilized nearly-cubic-tetragonal structure for all film thicknesses, studied here, up to 2100 nm.

  7. Elastic properties of supported polycrystalline thin films and multilayers: An X-ray diffraction study

    SciTech Connect

    Goudeau, P.; Villain, P.; Tamura, N.; Renault, P.-O.; Badawi, K.F.; Padmore, H.A.

    2003-08-13

    Numerous experimental and theoretical studies have shown that thin film elastic behavior may be different from the bulk one due to size effects related to grain boundaries, free surfaces and interfaces. In addition, thin films often present high compressive residual stresses which may be responsible of thin film buckling. These two features will be discussed in this communication through recent x-ray diffraction experiments: in situ tensile testing for elastic constant analysis and scanning x-ray micro diffraction for stress relaxation measurements associated with film buckling.

  8. Study of photoconductivity in Ni doped CdS thin films prepared by spray pyrolysis technique

    SciTech Connect

    Patidar, Manju Mishra Gangrade, Mohan; Nath, R.; Ganesan, V.; Ajay, Akhil; Wala, Arwa Dewas; N, Kiran; Panda, Richa

    2014-04-24

    Ni-doped cadmium sulphide [Cd{sub 1−x}Ni{sub x}S, (x=0, 0.03, 0.05 and 0.20)] thin films were investigated for photoconductive properties. The films were prepared by spray Pyrolysis technique (SPT). AFM and two probe resistivity measurements were carried out to analyze the morphological and electrical properties of the films. AFM shows the note worthy changes in the morphology where the nanorod structures in CdS is changed into nano particles with the Ni doping. The presence of persistence photo current is demonstrated and extensive photoconductivity analysis has been studied on these films.

  9. Molecular dynamics studies of thin film nucleation and substrate modification

    NASA Astrophysics Data System (ADS)

    Hu, Yanhong

    Deposition of energetic particles on solid surfaces has found increasing application in surface science. However, the detailed surface chemistry and relevant atomic mechanisms are not well understood. Molecular dynamics (MD) simulations are an ideal method to study these processes atomistically because they usually occur on short time scales (of the order of a few picoseconds). In this dissertation, MD simulations are performed to investigate thin film formation through organic cluster beam deposition and chemical modification of carbon nanotube/polymer composites via polyatomic ion beam deposition. The interatomic forces are calculated from the reactive empirical bond-order (REBO) potential for carbon-based systems coupled with the Lennard-Jones potentials. The reliability of this approach is examined by comparing its predictions for ethylene-cluster beam deposition with the results of a more accurate order-N nonorthogonal tight-binding method. The results show that the REBO potential captures the general characters of the relevant chemistry. The deposition processes of interest occur at room temperature; hence, appropriate temperature control methods must be employed in the simulations. A comparison study of four temperature control methods during the simulation of cluster deposition finds that the generalized Langevin equation approach is sufficient for dissipation of excess system energy if the deposition occurs on a large enough substrate at a moderate incident energy (<40 eV/cluster-atom). A new temperature control method has been developed for use at higher incident energies. In the simulations of thin film formation through organic cluster beam deposition, the dependence of the results on the intracluster bonding, incident angle and deposition direction is examined. Beams of ethylene clusters, adamantane molecules, and C20 molecules are thus deposited on a diamond surface with varying lateral momenta along two different crystallographic orientations at

  10. Study of NbC thin films for soft X-ray multilayer applications

    SciTech Connect

    Singh, Amol E-mail: rrcat.amol@gmail.com; Modi, Mohammed H.; Lodha, G. S.; Rajput, Parasmani; Jha, S. N.

    2015-06-24

    Compound materials are being used in soft x-ray and Extreme ultraviolet (EUV) optics applications. Structural properties of compound materials changes drastically when ultrathin films are formed from bulk material. Structural properties need to be investigated to determine the suitability of compound materials in soft x-ray multilayer applications. In the present study Niobium carbide (NbC) thin films were deposited using ion beam sputtering of an NbC target on Si (100) substrate. Thickness roughness and film mass density was determined from the X-ray reflectivity (XRR) data. XRR data revealed that the film mass density was increasing with increase in film thickness. For 500Ǻ thick film, mass density of 6.85 g/cm{sup 3}, close to bulk density was found. Rms roughness for all the films was less than 10Å. Local structure of NbC thin films was determined from EXAFS measurements. The EXAFS data showed an increase in Nb-C and Nb-(C)-Nb peak ratio approaches towards bulk NbC with increasing thickness of NbC. From the present study, NbC thin films were found suitable for actual use in soft x-ray multilayer applications.

  11. In-situ spectroscopic studies of electrochromic tungsten oxide films

    NASA Astrophysics Data System (ADS)

    Ozer, Nilgun; Demirbas, Muharrem; Ozyurt, Secuk

    2001-11-01

    Tungsten oxide thin films were prepared using an ethanolic solution of tungsten hexachloride (WCl6) by sol-gel spin coating. The films were spin coated on indium tin oxide (ITO) coated glass substrate at temperatures in the range of 100 to 450 degree(s)C. The films were characterized by x-ray diffractometry (XRD), scanning electron microscopy (SEM) UV- visible spectroscopy and cyclic voltammetry (CV). XRD showed that they had a polycrystalline WO3 structure for heat treatment temperatures at above 350 degree(s)C. The SEM examinations showed that the surface texture was very uniform and homogeneous. In situ electrochemical reduction of WO3/ITO (2M HCl) produced a blue color in less than a second. Coloration efficiency (CE) was found to be 21 cm2/mC. In situ spectroscopic investigations showed that these films could be used as a working electrode in electrochromic devices.

  12. Study of the photovoltaic effect in thin film barium titanate

    NASA Technical Reports Server (NTRS)

    Grannemann, W. W.; Dharmadhikari, V. S.

    1983-01-01

    The feasibility of making non-volatile digital memory devices of barium titanate, BaTiO3, that are integrated onto a silicon substrate with the required ferroelectric film produced by processing, compatible with silicon technology was examined.

  13. The structure study of thin semiconductor and dielectric films by diffraction of synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Yurjev, G. S.; Fainer, N. I.; Maximovskiy, E. A.; Kosinova, M. L.; Sheromov, M. A.; Rumyantsev, Yu. M.

    1998-02-01

    The structure of semiconductor and dielectric thin (100-300 nm) films was studied by diffraction of synchrotron radiation. The diffraction experiments were performed at both the station "Anomalous scattering" of the storage ring synchrotron facility VEPP-3 and DRON-4 diffractometer. The structure of CdS thin films grown on fused silica, single Si(100) and InP(100) substrates was investigated. The structure of Cu 2S thin films grown on fused silica, single Si(100) substrates and CdS/Si(100)-heterostructure was studied. The structure study was performed on Si 3N 4 films grown on GaAs(100) substrates. The structure of thin BN layers grown on single Si(100) substrates was studied. It was established that structural parameters of above-mentioned thin films coincide on the parameters of JCPDS International Centre for Diffraction Data.

  14. Growth and study of antimony selenide island films

    SciTech Connect

    Kushkhov, A. R.; Gaev, D. S.; Rabinovich, O. I.; Stolyarov, A. G.

    2013-03-15

    Nanosized Sb{sub 2}Se{sub 3} island films are prepared by the incongruent evaporation of Sb{sub 1-x}Se{sub x} (x = 0.9 at fractions) thin films. The surface morphology of the structures is investigated by optical and atomic force microscopy (AFM). It is shown that an increase in the evaporation temperature leads to a decrease in the surface density of islands.

  15. Study of the I-V characteristics of nanostructured Pd films on a Si substrate after vacuum annealing

    SciTech Connect

    Tomilin, S. V. Yanovsky, A. S.; Tomilina, O. A.; Mikaelyan, G. R.

    2013-06-15

    The I-V characteristics of nanostructured Pd films on a Si substrate are investigated. The nanostructures (nanoislands) are formed by the vacuum annealing of continuous ultrathin Pd films sputtered onto a substrate. The shape of the I-V characteristics of the investigated Si substrate-Pd film system is shown to be heavily dependent on the degree of film nanostructuring. The surface morphology of the films is studied using scanning electron microscopy.

  16. Film Study and the Teaching of English: Technology and the Future of Pedagogy.

    ERIC Educational Resources Information Center

    Gallagher, Brian

    1988-01-01

    Offers six predictions on the interrelated development of film technology and film study in the teaching of English. Sees the instructional centrality of the video cassette recorder in the near future, progressing to microcomputers, laser disks, and hybrid spoken-written-graphic text. (MM)

  17. The Influence of the MPAA's Film Rating System on Motion Picture Attendance: A Pilot Study.

    ERIC Educational Resources Information Center

    Austin, Bruce A.

    A study was undertaken to design and implement an experimental instrument for testing the influence of the Motion Picture Association of America's (MPAA) film rating system on movie attendance. Sixty-five high school students were given synopses of four different fictional films, each of which had been assigned an MPAA rating of G (approved for…

  18. Comparative study on properties of edible films based on pinhao (Araucaria angustifolia) starch and flour

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to develop and compare the properties of edible films based on pinhao starch and pinhao flour. Seven formulations were developed by casting methodology: 5% pinhao starch with 0, 1, 1.5, and 2% glycerol, and 5% pinhao flour with 1, 1.5, and 2% glycerol. The films were evalua...

  19. Teaching Film and Television in Developing Nations: A Malaysian Case Study.

    ERIC Educational Resources Information Center

    Hooper, Robert A.

    1997-01-01

    Recounts an American film studies professor's professional and personal experiences in teaching in Malaysia--the campus television studios burned to the ground the morning he arrived. Comments on the difficulties in film production in developing countries and on his Malaysian students' determination and capabilities. (PA)

  20. Uniting Hispanic Film Studies with Civic Engagement: A Chance for Personal Transformation

    ERIC Educational Resources Information Center

    Larson, Kajsa C.

    2015-01-01

    This current study presents a unique approach to the examination of Hispanic film through the incorporation of a civic engagement project, the Mayerson Student Philanthropy Project (MSPP), into the curriculum. Students examined and assessed important global issues, and how they are portrayed in films from several Spanish-speaking countries, while…

  1. Study of Photo-Conductivity in Nano-Crystalline Cadmium Telluride Thin Films

    SciTech Connect

    Mahesha, M. G.; Bangera, Kasturi V.; Shivakumar, G. K.

    2011-07-15

    Nano crystallite thin films of Cadmium Telluride have been grown on glass substrates by thermal evaporation under vacuum. The growth conditions to get stoichiometric films of the compound have been optimized. The effect of substrate temperature and annealing on photosensitivity has been investigated. Also the effect of deposition parameters and post deposition annealing on rise time and decay time have been studied in detail.

  2. A Technical, User and Cost Comparison Study of Microfiche Duplicate Film Material. Final Report.

    ERIC Educational Resources Information Center

    Prevel, James J.

    A technical, user and cost comparison study was undertaken to provide the Educational Resources Information Clearinghouse (ERIC) staff with data on silver halide, diazo, and vesicular type films for microfiche duplication. This information will allow ERIC to determine if diazo and/or vesicular films should be considered in producing ERIC duplicate…

  3. Experimental study of interfacial structure of a falling liquid film in a vertical pipe

    NASA Astrophysics Data System (ADS)

    Hasan, Abbas; Azzopardi, Barry; Hewakandamby, Buddhika

    2015-11-01

    Many studies in the literature provide time series data of the film thickness at one or two points on the pipe wall. Most of these studies focussed on either flat plates or small diameter pipes. The main aim of this paper is to study the characteristics of the interfacial wave structure of falling liquid films (liquid Reynolds numbers: 618-1670) in a large diameter pipe (127 mm) using a Multiple Pin Film Sensor (MPFS) which is capable of providing measurements of film thickness and interfacial waves with excellent resolution in time and in the circumferential and axial directions. Parameters, such as film thicknesses, wave velocities and frequencies were extracted. 3D interfacial wave structures were reconstructed from the film thickness data. Unlike the waves in smaller diameter pipes which are characterised as coherent rings, the waves seen in this study were much localized. The mean film thicknesses are generally in good agreement with published models. The mean film thickness obtained from MPFS was also compared with the conductance ring pairs. There is good agreement between the two methods particularly when the fact that the ring pair technique provides a circumferentially averaged value. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  4. Active Learning through Student Film: A Case Study of Cultural Geography

    ERIC Educational Resources Information Center

    Anderson, Jon

    2013-01-01

    This study contributes to the debate over the potential of film as a pedagogical aid. It argues that integrating film production into the assessment of undergraduate modules secures advantages for student learning: students connect their ideas more explicitly to "real world" examples; new voices and understandings are introduced to…

  5. Towards a Decolonising Pedagogy: Understanding Australian Indigenous Studies through Critical Whiteness Theory and Film Pedagogy

    ERIC Educational Resources Information Center

    Hook, Genine

    2012-01-01

    This article explores student and teacher engagement with Australian Indigenous Studies. In this article I identify key themes in the film "September" (2007) that demonstrate how the film can be used as a catalyst for student learning and discussion. Critical whiteness theory provides a framework to explore three themes, the invisibility of…

  6. Highly ordered thin films of polyheterocycles: A synchrotron radiation study of polypyrrole and polythiophene Langmuir-Blodgett films

    SciTech Connect

    Skotheim, T.A.; Yang, X.Q.; Chen, J.; Hale, P.D.; Inagaki, T.; Samuelson, L.; Tripathy, S.; Hong, K.; Rubner, M.F.; den Boer, M.L.

    1988-01-01

    Langmuir-Blodgett films have been made with 3-n-hexadecylpyrrole and 3-n-octadecylpyrrole monomers and copolymers with unsubstituted pyrrole made by chemical polymerization at the air-water interface on a subphase containing FeCl/sub 3/. Langmuir-Blodgett films consisting of mixtures of stearic acid and alkylsubstituted polythiophenes have also been made as bilayer films. The orientation of single and multilayer films on platinum substrates have been studied by Near Edge X-ray Absorption Fine Structure Spectroscopy which also gives information about charge transfer interactions between the aromatic groups and the metallic substrates. The alkylsubstituted pyrroles form highly ordered two-dimensional structures. FeCl/sub 3/ initiated copolymerization with unsubstituted pyrrole leads to a more disordered system. In the case of polythiophene-stearic acid bilayers, the stearic acid layers are highly ordered. The poly(alkyl thiophene) layers sandwiched between stearic acid layers, on the other hand, exhibit random orientation of the thiophene moieties. 15 refs., 3 figs., 3 tabs.

  7. Size effect study of thin film hardness using AFM nano-indentation

    NASA Astrophysics Data System (ADS)

    Xu, Linyan; Qian, Shuangbei; Li, Juan; Liu, Congcong; Guo, Shijia; Huang, Di; Wu, Sen; Hu, Xiaodong

    2015-10-01

    With nano-level spatial and force resolution, atomic force microscope (AFM) becomes an indispensable nanoindentation measurement instrument for thin films and soft films. To do the research of size effect of the hardness property of thin films, indentation experiments have been done on a gold film with 200 nm thickness and a silicon nitride film with 110 nm thickness. It is possible to change the maximum load forces to get discrete residual depths on the film samples. The contact depths of the gold film are 15.91 nm and 26.67 nm respectively, while the contact depths of the silicon nitride film are 7.82 nm and 10.25 nm respectively. A group of nanoindentation force curves are recorded for the transformation into force-depth curves. Subsequently, a 3D image of the residual indentation can be obtained by in-situ scanning immediately after nanoindentation. The topography data is imported into a Matlab program to estimate the contact area of the indentation. For the gold film, the hardness parameters of 3.31 GPa and 2.57 GPa are calculated under the above two contact depths. And for silicon nitride film, the corresponding results are 6.51GPa and 3.58 GPa. The experimental results illustrate a strong size effect for thin film hardness. The correction of the residual indentation image of the gold film is also done as an initial study. Blind tip reconstruction (BTR) algorithm is introduced to calibrate the tip shape, and more reliable hardness values of 1.15 GPa and 0.94 GPa are estimated.

  8. Hydroxyapatite thin films grown by pulsed laser deposition and radio-frequency magnetron sputtering: comparative study

    NASA Astrophysics Data System (ADS)

    Nelea, V.; Morosanu, C.; Iliescu, M.; Mihailescu, I. N.

    2004-04-01

    Hydroxyapatite (HA) thin films for applications in the biomedical field were grown by pulsed laser deposition (PLD) and radio-frequency magnetron sputtering (RF-MS) techniques. The depositions were performed from pure hydroxyapatite targets on Ti-5Al-2.5Fe (TiAlFe) alloys substrates. In order to prevent the HA film penetration by Ti atoms or ions diffused from the Ti-based alloy during and after deposition, the substrates were pre-coated with a thin buffer layer of TiN. In both cases, TiN was introduced by reactive PLD from TiN targets in low-pressure N 2. The PLD films were grown in vacuum onto room temperature substrates. The RF-MS films were deposited in low-pressure argon on substrates heated at 550 °C. The initially amorphous PLD thin films were annealed at 550 °C for 1 h in ambient air in order to restore the initial crystalline structure of HA target. The thickness of the PLD and RF-MS films were ˜1 μm and ˜350 nm, respectively. All films were structurally studied by scanning electron microscopy (SEM), grazing incidence X-ray diffraction (GIXRD), energy dispersive X-ray spectrometry (EDS) and white light confocal microscopy (WLCM). The mechanical properties of the films were tested by Berkovich nano-indentation. Both PLD and RF-MS films mostly contain HA phase and exhibit good mechanical characteristics. Peaks of CaO were noticed as secondary phase in the GIXRD patterns only for RF-MS films. By its turn, the sputtered films were smoother as compared to the ones deposited by PLD (50 nm versus 250 nm average roughness). The RF-MS films were harder, more mechanically resistant and have a higher Young modulus.

  9. Formation and dissolution of the passive film on iron studied by a light reflectance technique

    SciTech Connect

    Buechler, M.; Schmuki, P.; Boehni, H.

    1997-07-01

    The formation, growth, and dissolution of the passive film on iron in neutral and alkaline solutions was investigated using a light reflectance technique. In this study, laser light of 325 nm was used to access the amount of light absorbed in the film and to evaluate the optical absorption coefficient. After calibration, this technique allows a fast, in situ determination of the film thickness. Cyclic voltammetry and potential-step experiments with simultaneous thickness monitoring were carried out in borate buffer and in 0.1 M NaOH. For the borate buffer, anodic film formation and cathodic film dissolution are reversible, i.e., repeated anodic/cathodic cycling leads to conditions identical to the initial state. In NaOH, cathodic reduction of the film does not lead to film dissolution but to the formation of an electrochemically active layer, which does not significant contribute to the potential drop in the metal/film/electrolyte system. Hence, repeated passivation and reduction leads to successive thickening of the film, consisting of a barrier layer of constant thickness and a porous layer having increased thickness with every passivation/reduction cycle. This layer does not contribute to the passivity of iron.

  10. Growth and Etch Rate Study of Low Temperature Anodic Silicon Dioxide Thin Films

    PubMed Central

    Ashok, Akarapu; Pal, Prem

    2014-01-01

    Silicon dioxide (SiO2) thin films are most commonly used insulating films in the fabrication of silicon-based integrated circuits (ICs) and microelectromechanical systems (MEMS). Several techniques with different processing environments have been investigated to deposit silicon dioxide films at temperatures down to room temperature. Anodic oxidation of silicon is one of the low temperature processes to grow oxide films even below room temperature. In the present work, uniform silicon dioxide thin films are grown at room temperature by using anodic oxidation technique. Oxide films are synthesized in potentiostatic and potentiodynamic regimes at large applied voltages in order to investigate the effect of voltage, mechanical stirring of electrolyte, current density and the water percentage on growth rate, and the different properties of as-grown oxide films. Ellipsometry, FTIR, and SEM are employed to investigate various properties of the oxide films. A 5.25 Å/V growth rate is achieved in potentiostatic mode. In the case of potentiodynamic mode, 160 nm thickness is attained at 300 V. The oxide films developed in both modes are slightly silicon rich, uniform, and less porous. The present study is intended to inspect various properties which are considered for applications in MEMS and Microelectronics. PMID:24672287

  11. Comparative study of the mechanical properties of nanostructured thin films on stretchable substrates

    SciTech Connect

    Djaziri, S.; Renault, P.-O.; Le Bourhis, E.; Goudeau, Ph.; Faurie, D.; Geandier, G.; Mocuta, C.; Thiaudière, D.

    2014-09-07

    Comparative studies of the mechanical behavior between copper, tungsten, and W/Cu nanocomposite based on copper dispersoïd thin films were performed under in-situ controlled tensile equi-biaxial loadings using both synchrotron X-ray diffraction and digital image correlation techniques. The films first deform elastically with the lattice strain equal to the true strain given by digital image correlation measurements. The Cu single thin film intrinsic elastic limit of 0.27% is determined below the apparent elastic limit of W and W/Cu nanocomposite thin films, 0.30% and 0.49%, respectively. This difference is found to be driven by the existence of as-deposited residual stresses. Above the elastic limit on the lattice strain-true strain curves, we discriminate two different behaviors presumably footprints of plasticity and fracture. The Cu thin film shows a large transition domain (0.60% true strain range) to a plateau with a smooth evolution of the curve which is associated to peak broadening. In contrast, W and W/Cu nanocomposite thin films show a less smooth and reduced transition domain (0.30% true strain range) to a plateau with no peak broadening. These observations indicate that copper thin film shows some ductility while tungsten/copper nanocomposites thin films are brittle. Fracture resistance of W/Cu nanocomposite thin film is improved thanks to the high compressive residual stress and the elimination of the metastable β-W phase.

  12. Experimental Study of Vane Heat Transfer and Film Cooling at Elevated Levels of Turbulence

    NASA Technical Reports Server (NTRS)

    Ames, Forrest E.

    1996-01-01

    This report documents the results of an experimental study on the influence of high level turbulence on vane film cooling and the influence of film cooling on vane heat transfer. Three different cooling configurations were investigated which included one row of film cooling on both pressure and suction surfaces, two staggered rows of film cooling on both suction and pressure surfaces, and a shower-head cooling array. The turbulence had a strong influence on film cooling effectiveness, particularly on the pressure surface where local turbulence levels were the highest. For the single row of holes, the spanwise mixing quickly reduced centerline effectiveness levels while mixing in the normal direction was more gradual. The film cooling had a strong influence on the heat transfer in the laminar regions of the vane. The effect of film cooling on heat transfer was noticeable in the turbulent regions but augmentation ratios were significantly lower. In addition to heat transfer and film cooling, velocity profiles were taken downstream of the film cooling rows at three spanwise locations. These profile comparisons documented the strong spanwise mixing due to the high turbulence. Total pressure exit measurements were also documented for the three configurations.

  13. Structural Study And Optical Properties Of TiO{sub 2} Thin Films Elaborated By Thermal Oxidation Of RF Magnetron Sputtered Ti Films

    SciTech Connect

    Guitoume, D.; Achour, S.; Guittoum, A.; Abaidia, S. E. H.

    2008-09-23

    We report on the effect of thickness on the structural and optical properties of TiO{sub 2} thin films obtained by direct exposure of Ti metal film to thermal oxidation. Ti thin films with thicknesses ranging from 87 nm to 484 nm were deposited onto glass substrate by RF magnetron sputtering. Thereafter, the as-deposited Ti films were annealed in air at temperature equal to 520 deg. C. The structural evolution and optical properties of obtained TiO{sub 2} films were studied by means of Rutherford backscattering spectrometry (RBS), grazing incidence X-ray diffraction (GIXRD), scanning electron microscopy (SEM) and UV-Visible spectroscopy. The films thicknesses were extracted from RBS spectra. From X-ray diffraction spectra, we can see that all the films present three TiO{sub 2} phases (anatase, rutile and Brookite). The anatase and rutile phases exhibit a strong preferred orientation along (004) and (210) planes respectively. The grain sizes, D (nm), did not change much with increasing thickness. The average value of (nm) was equal to 29 nm for anatase and 26 nm for rutile. The micrographs taken from SEM experiments indicate that the films present a dense micro structure with very small grains. Transmittance spectra show that all the films present a good transparency in the visible region. The dependence of transmittance, optical band gap and refractive index on the thickness of the films was also studied.

  14. A study on various fabrication routes for preparing multilayered cubic boron nitride films and sp(3)-like boron nitride films

    NASA Astrophysics Data System (ADS)

    Wong, Sing Fai

    Cubic boron nitride (cBN) has a sp3-bonded structure which leads to excellent mechanical properties. Though cBN-rich films have been successfully fabricated by many techniques, the adhesion of the films is still unsatisfactory due to the high stresses. The maximum sustainable thickness of cBN-rich films with good adhesion is widely reported to be around 200 nm, so many practical applications of cBN coatings are hindered. In this study, we designed a series of deposition schemes in a logical sequence, in order to explore whether stress can be released, or other structural forms of BN with potential applications can be made, and to gain more fundamental understanding on the growth mechanisms of various phases observed in the films. Various fabrication processes were employed according to the following sequence: (1) A single-step process. It was showed that the maximum tolerable thickness of the cBN-rich films prepared by our system (183nm) was compatible with the result in literatures (200nm). (2) A multilayered deposition process. A thick sp2-bonded boron nitride (sP2-BN) buffer layer which was relatively deformable was added, and hence some stresses were released so as to allow a 643nm-thick, 87vol.% cBN-rich layer with acceptable adhesion to grow on top. (3) An advanced multilayer process with subsequent annealing process. A zirconium layer was pre-deposited to remove the soft buffer layer after postannealing. The interface could be strengthened as the zirconium-boride/nitride was formed. (4) Ion assist deposition at unheated condition. Composite BN films containing sp3 nanoclusters embedded in a sp2-BN matrix were fabricated. The IR technique was not sensitive enough to detect spa nanoclusters, but their presence was verified by the results of other measurements. In particular, the sp3 content can be over 30vo1.%, with a hardness 20GPa. The influences of the assist beam energy and substrate temperature on the generation of the sp3 nanoclusters were investigated

  15. a Study of Diamond Thin Film and Diamondlike Carbon Film Deposition Using Electron Cyclotron Resonance Microwave Discharges

    NASA Astrophysics Data System (ADS)

    Kuo, Szu-Cherng

    1991-02-01

    The electron cyclotron resonance (ECR) plasma is very useful for thin film technologies since it enables: (1) generation of a very dense plasma with n_ {rm e} > 10 ^{11}/cm^3 at f = 2.45 GHz; (2) generation of a highly ionized plasma (ionization degree > 1%); (3) generation of a plasma in the low pressure regime (10^ {-4} - 10^{-2} Torr); (4) generation of a radically homogeneous plasma column with large diameters; and (5) acceleration of the plasma in an inhomogeneous magnetic field. A large variety of deposition techniques have been used to prepare diamond thin films and diamondlike carbon (DLC) films. ECR plasma-assisted chemical vapor deposition (PACVD) is a new technique currently receiving much interest. The ECR plasma system offers a more complex parameter space than the more conventional PACVD processes. These include magnetic confinement of the plasma, independent source control over the dissociation of reaction gases, independent substrate bias of DC or RF voltage, independent substrate temperature control, downstream plasma operation and the magnetic mirror configuration which allows for the extraction of specific ion energies from the plasma chamber. In this work we have set up an ECR plasma-assisted materials processing system. A Lisitano coil is used to effectively couple microwave energy into the plasma, and a divergent magnetic field configuration is used to push the plasma out of the Lisitano coil. Langmuir probe measurements and optical emission spectroscopy were performed to characterize the ECR plasma. We have deposited hard DLC films on silicon substrates using this ECR plasma system. The deposition was operated at a -200 V DC bias, substrate temperature T = 200^circC, pressure P= 5*10^{-4} Torr using CH _4 as the reaction gas. The diamond thin film deposition using ECR PACVD technique has produced some initial results. Further studies into the effects of dense ion flux in the ECR plasma on diamond formation is needed.

  16. Structural phase study in un-patterned & patterned PVDF semi-crystalline films

    NASA Astrophysics Data System (ADS)

    Pramod, K.; Gangineni, Ramesh Babu

    2014-04-01

    This work explores the structural phase studies of organic polymer- polyvinylidene fluoride (PVDF) thin films in semi-crystallized phase and nano-patterned PVDF thin films. The nanopatterns are transferred with the CD layer as a master using soft lithography technique. The semi-crystalline PVDF films were prepared by a still and hot (SH) method, using a homemade spin coater that has the proficiency of substrate heating by a halogen lamp. Using this set up, smooth PVDF thin films in semi-crystalline α-phase were prepared using 2-Butanone as solvent. XRD, AFM & confocal Raman microscope have been utilized to study the structural phase, crystallinity and quality of the films.

  17. Structural phase study in un-patterned and patterned PVDF semi-crystalline films

    SciTech Connect

    Pramod, K. Gangineni, Ramesh Babu

    2014-04-24

    This work explores the structural phase studies of organic polymer- polyvinylidene fluoride (PVDF) thin films in semi-crystallized phase and nano-patterned PVDF thin films. The nanopatterns are transferred with the CD layer as a master using soft lithography technique. The semi-crystalline PVDF films were prepared by a still and hot (SH) method, using a homemade spin coater that has the proficiency of substrate heating by a halogen lamp. Using this set up, smooth PVDF thin films in semi-crystalline α-phase were prepared using 2-Butanone as solvent. XRD, AFM and confocal Raman microscope have been utilized to study the structural phase, crystallinity and quality of the films.

  18. Impedance Spectroscopy Study of Composite Thin Films of Hydrated Polyethylene Glycol

    SciTech Connect

    Al-Hamarneh, Ibrahim F.; Pedrow, Patrick D.; Goheen, Steven C.; Hartenstine, M. J.

    2007-05-01

    A polythelene glycol (PEG) polymer was synthesized using a dip coating procedure on 316L stainless steel (SS) substrate pre coated by radio frequency RF inductively coupled plasma polymerization with di (ethylene glycol) vinyl ether (EO2V) monomer that was used as a primer coat. The primer and PEG composite film was studied with profilometer, visible-light microscope, scanning electron microscope (SEM) and a tape test to evaluate thickness, stability, morphology and adhesion. Response of the PEG composite film to an AC electric perturbation was studied as a function of hydration state using impedance spectroscopy (IS). A resistor/capacitor network was used to interpret the impedance spectra. The capacitance of the PEG film decreased with an exponentially decaying term as dehydration progressed. PEG film capacitance decay was consistent with a model describing water molecules diffusing through the PEG film.

  19. Impedance Spectroscopy Study of Composite Thin Films of Hydrated Polyethylene Glycol

    SciTech Connect

    Al-Hamarneh, Ibrahim F.; Pedrow, Patrick D.; Goheen, Steven C.; Hartenstine, M. J.

    2007-10-01

    A polyethylene glycol (PEG) polymer was synthesized using a dip coating procedure on 316L stainless steel (SS) substrate pre-coated with a primer that consisted of radio frequency RF inductively coupled plasma-polymerized di (ethylene glycol) vinyl ether (EO2V). The primer and PEG composite film was studied with profilometer, optical microscope, scanning electron microscope (SEM), and a tape test to evaluate thickness, coverage, morphology, and adhesion, respectively. Response of the PEG composite film to an applied AC voltage was studied as a function of hydration state using impedance spectroscopy (IS). A resistor/capacitor network was used to interpret the impedance spectra. Electrical capacitance of the PEG film decreased with an exponentially decaying term as dehydration progressed. PEG film capacitance decay was consistent with a model describing water molecules diffusing through the PEG film.

  20. Transport studies on La0.8-xPr0.2SrxMnO3 manganite films

    NASA Astrophysics Data System (ADS)

    Solanki, P. S.; Doshi, R. R.; Ravalia, Ashish; Keshvani, M. J.; Pandya, Swati; Ganesan, V.; Shah, N. A.; Kuberkar, D. G.

    2015-05-01

    In this communication, we report the results of the studies on structural, microstructural, transport and magnetotransport behavior of La0.8-xPr0.2SrxMnO3 (LPSMO) (x=0.1, 0.2 and 0.3) manganite films grown on (100) single crystalline SrTiO3 (STO) substrate using low cost chemical solution deposition (CSD) method. Films with similar compositions were also grown using sophisticated pulsed laser deposition (PLD) technique and results of structural and transport studies obtained for CSD grown films were compared with PLD grown films. Structural studies show that all the CSD and PLD grown films possess single crystalline nature with compressive and tensile strain, respectively. Surface morphology, studied using atomic force microscope (AFM), reveals the island like grain morphology in CSD grown films while PLD grown films possess smooth film surfaces. Carrier density dependent transport properties of the films have been discussed in the context of zener double exchange (ZDE) mechanism. Lower resistivity and higher transition temperature (TP) observed in CSD grown films as compared to PLD grown films have been discussed in the light of structural strain and surface morphology of the films. Various models and mechanisms have been employed to understand the charge transport in CSD and PLD grown films. Also, observation of low temperature resistivity minima behavior in all the CSD and PLD grown LPSMO films has been explained in the context of electron-electron scattering mechanism.

  1. Nonlinear Optical Properties of Organic and Polymeric Thin Film Materials of Potential for Microgravity Processing Studies

    NASA Technical Reports Server (NTRS)

    Abdeldayem, Hossin; Frazier, Donald O.; Paley, Mark S.; Penn, Benjamin; Witherow, William K.; Bank, Curtis; Shields, Angela; Hicks, Rosline; Ashley, Paul R.

    1996-01-01

    In this paper, we will take a closer look at the state of the art of polydiacetylene, and metal-free phthalocyanine films, in view of the microgravity impact on their optical properties, their nonlinear optical properties and their potential advantages for integrated optics. These materials have many attractive features with regard to their use in integrated optical circuits and optical switching. Thin films of these materials processed in microgravity environment show enhanced optical quality and better molecular alignment than those processed in unit gravity. Our studies of these materials indicate that microgravity can play a major role in integrated optics technology. Polydiacetylene films are produced by UV irradiation of monomer solution through an optical window. This novel technique of forming polydiacetylene thin films has been modified for constructing sophisticated micro-structure integrated optical patterns using a pre-programmed UV-Laser beam. Wave guiding through these thin films by the prism coupler technique has been demonstrated. The third order nonlinear parameters of these films have been evaluated. Metal-free phthalocyanine films of good optical quality are processed in our laboratories by vapor deposition technique. Initial studies on these films indicate that they have excellent chemical, laser, and environmental stability. They have large nonlinear optical parameters and show intrinsic optical bistability. This bistability is essential for optical logic gates and optical switching applications. Waveguiding and device making investigations of these materials are underway.

  2. Polytetrafluoroethylene transfer film studied with X-ray photoelectron spectroscopy

    NASA Technical Reports Server (NTRS)

    Wheeler, D. R.

    1980-01-01

    Polytetrafluoroethylene (PTFE) was rubbed against nickel in ultrahigh vacuum at loads up to 3.9 N and speeds up to 94 mm/sec. The transfer film formed on the nickel was analyzed using X-ray phototectron spectroscopy. The film was indistinguishable from bulk PTFE except for the possible presence of a small amount of NiF2. The transfer film was found to be about 1 molecule (0.5 nm) thick under all conditions; but at speeds above 10 mm/sec, there was evidence of bulk transfer in the form of fragments as well. The thickness measurements required a choice among conflicting published values of the inelastic mean free path for electrons in polymers. The values chosen gave internally consistent results.

  3. Polyvinyl chloride meat-wrapping film study. Final report

    SciTech Connect

    Vandervort, R.

    1988-01-01

    As a result of worker complaints in the Baltimore, Maryland area, potential health hazards associated with the use of polyvinyl-chloride film for wrapping meat were reviewed. Fumes generated during the meat-wrapping process were causing concern among the workers as they experienced respiratory irritation and distress. It appeared that only some of the meat wrappers experienced difficulty, only some of the rolls of film-produced irritations in the affected workers, and affected workers had prior histories of respiratory difficulties. Fumes were generated during hot-wire film cutting. The amount of fume generated depended significantly on the care taken during the operation. If the dispensing machines were improperly adjusted, large amounts of fumes could be obtained during the cutting process. The author concludes that the amounts of these chemicals released during this operation does not constitute a health hazard to the employees. It may be necessary, however, to remove persons with prior respiratory irritation from this particular job location.

  4. Corrosion inhibitor film formation studied by ATR-FTIR

    SciTech Connect

    Campbell, S.; Jovancicevic, V.

    1999-11-01

    The development of an inhibitor film is essential for the effective performance of a corrosion inhibitor. The use of attenuated total reflection fourier transform infrared spectroscopy (ATR-FTIR) allows the development of inhibitor films on iron oxides to be monitored. For two distinct corrosion inhibitor chemistries, oleic imidazoline and phosphate ester, the film formation and corrosion processes are monitored on Fe{sub 3}O{sub 4} in a powdered form (a model surface). Additional data following on the physical and chemical properties are obtained using XPS and SEM techniques, which allows for a more complete characterization of the model inhibitor/oxide system. By the proper choice of system and measurement techniques, the complex phenomenon of corrosion inhibition may be analyzed directly.

  5. NEXAFS Study of Air Oxidation for Mg Nanoparticle Thin Film

    NASA Astrophysics Data System (ADS)

    Ogawa, S.; Murakami, S.; Shirai, K.; Nakanishi, K.; Ohta, T.; Yagi, S.

    2013-03-01

    The air oxidation reaction of Mg nanoparticle thin film has been investigated by Mg K-edge NEXAFS technique. It is revealed that MgO is formed on the Mg nanoparticle surfaces at the early stage of the air oxidation for Mg nanoparticle thin film. The simulation of NEXAFS spectrum using standard spectra indicates the existence of complex magnesium carbonates (x(MgCO3).yMg(OH2).z(H2O)) in addition to MgO at the early stage of the air oxidation.

  6. Structural, morphological and Raman studies of pulse electrosynthesised indium antimonide thin films

    NASA Astrophysics Data System (ADS)

    Singh, Joginder; Chandel, Tarun; Rajaram, P.

    2015-08-01

    InSb films deposited on fluorine doped tin oxide (FTO) substrates by a pulse elctrodeposition technique. The deposition was carried out at an applied potential -1.3V versus Ag/AgCl electrode. Structural, morphological and optical studies were performed on the electrodeposited InSb. X-ray diffraction (XRD) studies show that the deposited InSb films are polycrystalline in nature having the zinc blend structure. The crystallite size (D), dislocation density (δ) and strain (ɛ) were calculated using XRD results. The EDAX analysis shows that chemical composition of In3+ and Sb3+ ions is close to the required stoichiometry. The surface morphology of the deposited films was examined using scanning electron scanning electron microscopy (SEM). SEM studies reveal that the surface of the films is uniformly covered with submicron sized spherical particles. However, the crystallite size determined by the Scherrer method shows a size close to 30 nm. Surface morphology studies of the InSb films were also performed using atomic force microscopy (AFM). The average surface roughness as measured by AFM is around 40 nm. Hot probe studies show that all the electrodeposited thin films have n type conductivity and the thickness of the films is calculated using electrochemical formula.

  7. Structural, morphological and Raman studies of pulse electrosynthesised indium antimonide thin films

    SciTech Connect

    Singh, Joginder Chandel, Tarun; Rajaram, P.

    2015-08-28

    InSb films deposited on fluorine doped tin oxide (FTO) substrates by a pulse elctrodeposition technique. The deposition was carried out at an applied potential −1.3V versus Ag/AgCl electrode. Structural, morphological and optical studies were performed on the electrodeposited InSb. X-ray diffraction (XRD) studies show that the deposited InSb films are polycrystalline in nature having the zinc blend structure. The crystallite size (D), dislocation density (δ) and strain (ε) were calculated using XRD results. The EDAX analysis shows that chemical composition of In{sup 3+} and Sb{sup 3+} ions is close to the required stoichiometry. The surface morphology of the deposited films was examined using scanning electron microscopy (SEM). SEM studies reveal that the surface of the films is uniformly covered with submicron sized spherical particles. However, the crystallite size determined by the Scherrer method shows a size close to 30 nm. Surface morphology studies of the InSb films were also performed using atomic force microscopy (AFM). The average surface roughness as measured by AFM is around 40 nm. Hot probe studies show that all the electrodeposited thin films have n type conductivity and the thickness of the films is calculated using electrochemical formula.

  8. Surface film effects on drop tube undercooling studies

    NASA Technical Reports Server (NTRS)

    Ethridge, E. C.; Kaukler, W. F.

    1986-01-01

    The effects of various gaseous atmospheric constituents on drop-tube solidified samples of elemental metals were examined from a microstructural standpoint. All specimens were prepared from the purest available elements, so effects of impurities should not account for the observed effects. The drop-tube gas has a definite effect on the sample microstructure. Most dramatically, the sample cooling rate is effected. Some samples receive sufficient cooling to solidify in free fall while others do not, splating at the end of the drop tube in the sample catcher. Gases are selectively absorbed into the sample. Upon solidification gas can become less soluble and as a result forms voids within the sample. The general oxidation/reduction characteristics of the gas also affect sample microstructures. In general, under the more favorable experimental conditions including reducing atmospheric conditions and superheatings, examination of sample microstructures indicates that nucleation has been suppressed. This is indicated by underlying uniform dendrite spacings throughout the sample and with a single dendrite orientation through most of the sample. The samples were annealed yielding a few large grains and single or bi-crystal samples were commonly formed. This was especially true of samples that were inadvertently greatly superheated. This is in contrast with results from a previous study in which surface oxides were stable and contained numerous sites of nucleation. The number of nucleation events depends upon the surface state of the specimen as determined by the atmosphere and is consistent with theoretical expectations based upon the thermodynamic stability of surface oxide films. Oxide-free specimens are characterized by shiny surfaces, with no observable features under the scanning electron microscope at 5000X.

  9. X-Ray Studies of Thin Films and Interfaces.

    NASA Astrophysics Data System (ADS)

    Woronick, Steven Charles

    1990-01-01

    Presented here are a series of x-ray studies utilizing synchrotron radiation to investigate a variety of properties of thin films and interfaces in technologically important materials. By far the largest part of this dissertation is devoted to studies of x-ray reflectivity as a function of angle (mainly soft x rays), although some extended x -ray absorption fine structure (EXAFS) results are included as reprinted published papers (briefly discussed). The reflectivity discussion covers theory, experimental techniques, data analysis (by curve-fitting), and specific applications. The material systems studied by the x-ray reflectivity technique include: bulk silicon, GaAs, InAs, ~250 -A InAs layers deposited by molecular-beam epitaxy (MBE) on GaAs(100) substrates, four thicknesses (~ 126-1100 A) of SiO_2 /Si(100) produced by dry thermal oxidation, and ~250-A layers of CoSi_2 /Si(111) (two samples, one produced by MBE and one by solid-phase epitaxy). Results determined from the reflectivity measurements include: interfacial roughness parameters, refractive index of materials (in the energy range ~400-1100 eV), and overlayer thicknesses. It has been found for example that the indium -stabilized growth mode of InAs on GaAs(100) results in a smoother buried interface than the arsenic-stabilized growth mode, while the indium-stabilized growth mode on 2^circ-off GaAs(100) produces the smoothest buried interface (with typical roughness parameters in the range 10-19 A). Preliminary results indicate that growth of CoSi_2/Si(111) by MBE produces smoother buried interfaces than growth by solid-phase epitaxy. The roughness parameters have been explained in terms of growth conditions, lattice mismatch, and material inhomogeneity in the vicinity of the buried interface. The oxygen atomic scattering factor for photons in the range 400-800 eV (oxygen K edge ~ 540 eV) has also been deduced from a determination the Si and SiO_2 refractive indices. The EXAFS studies were used to

  10. A comparison study of textural features between FFDM and film mammogram images

    NASA Astrophysics Data System (ADS)

    Jing, Hao; Yang, Yongyi; Wernick, Miles N.; Yarusso, Laura M.; Nishikawa, Robert M.

    2011-03-01

    In this work, we conducted an imaging study to make a direct, quantitative comparison of image features measured by film and full-field digital mammography (FFDM). We acquired images of cadaver breast specimens containing simulated microcalcifications using both a GE digital mammography system and a screen-film system. To quantify the image features, we calculated and compared a set of 12 texture features derived from spatial gray-level dependence matrices. Our results demonstrate that there is a great degree of agreement between film and FFDM, with the correlation coefficient of the feature vector (formed by the 12 textural features) being 0.9569 between the two; in addition, a paired sign test reveals no significant difference between film and FFDM features. These results indicate that textural features may be interchangeable between film and FFDM for CAD algorithms.

  11. Photocatalytic activity and reusability study of nanocrystalline TiO2 films prepared by sputtering technique

    NASA Astrophysics Data System (ADS)

    Barrocas, B.; Monteiro, O. C.; Jorge, M. E. Melo; Sério, S.

    2013-01-01

    The photocatalytic activity of nanocrystalline titanium dioxide (TiO2) films deposited on unheated glass substrates by DC reactive magnetron sputtering at different oxygen partial pressures was tested on the decolorization of Rhodamine 6G (Rh6G) aqueous solutions. The dye photodecolorization process was studied considering the influence of the crystallinity and preferred orientation of growth of the prepared films. It was found that the higher photocatalytic activity was achieved by the film with preferred orientation of growth along the (1 0 1) crystal direction and showing a vestigial rutile phase in a mainly anatase phase. The recycling catalytic ability of the TiO2 films was also evaluated and a promising photocatalytic performance has been revealed with a very low variation of the decay rate after five consecutive usages. Structural and morphological characterization revealed high photochemical stability of the films after successive photodegradations assays.

  12. Uranium dioxide films with xenon filled bubbles for fission gas behavior studies

    NASA Astrophysics Data System (ADS)

    Usov, I. O.; Dickerson, R. M.; Dickerson, P. O.; Byler, D. D.; McClellan, K. J.

    2014-09-01

    Electron beam evaporation and ion beam assisted deposition (IBAD) methods were utilized to fabricate depleted UO2 films and UO2 films with embedded Xe atoms, respectively. The films were fabricated at elevated temperature of 700 °C and also subsequently annealed at 1000 °C to induce grain growth and Xe atom redistribution. The goal of this work was to synthesize reference UO2 samples with controlled microstructures and Xe-filled bubble morphologies, without the effects attendant to rector irradiation-induced fission. Transmission electron microscopy (TEM) microstructural characterization revealed that fine Xe-filled bubbles nucleated in the as grown films and subsequent annealing resulted in noticeable bubble size increase. Reported results demonstrate the great potential IBAD techniques and UO2 films have for various areas of nuclear materials studies.

  13. A study on the magnetic behavior of Nd-Fe-B/α-Fe nanocomposite films

    NASA Astrophysics Data System (ADS)

    Madeswaran, S.; Tamano, S.; Goto, S.; Tokiwa, K.

    2010-06-01

    Nanocomposite Nd-Fe-B / α-Fe thin films were prepared by sputtering successively a Nd-rich Nd21Fe64B15 and a Fe targets in a multilayer structure using radio frequency (RF) magnetron gun. We have studied the influence of thickness of α-Fe layer on the magnetic properties of Nd-Fe-B / α-Fe thin films. A nanocomposite thin film with 15nm thick α-Fe layer prepared on 550°C heated substrate gives the highest energy product, 190 kJ/m3 along with a coercivity of 950 kA/m. Magnetic hysteresis loop measurement shows that the hard (Nd-Fe-B) and soft (α-Fe) layers are exchange coupled firmly for the films deposited on heated substrate whereas the two layers are decoupled for room temperature deposited and post annealed films.

  14. Influence of Ligands on the Formation of Kesterite Thin Films for Solar Cells: A Comparative Study.

    PubMed

    Huang, Tang Jiao; Yin, Xuesong; Tang, Chunhua; Qi, Guojun; Gong, Hao

    2016-05-10

    The preparation of solar-cell-grade Cu2 ZnSnS4 (CZTS) thin films from ligand-capped small-grained CZTS particles remains hindered by problems of phase segregation, composition non-uniformity, and in particular carbon-layer formation. Herein, through a systematic comparative study of annealed films of CZTS nanocrystals prepared using conventional oleylamine and those prepared using formamide, these problems are found to be mainly attributable to the influence of the ligands, and mechanisms are proposed. Importantly, the origin of the carbon layer in oleylamine-capped CZTS films is revealed to be the reaction between oleylamine and sulfur. This carbon layer has a very poor electrical conductivity, which can be the reason for the limited performance of such films. Fortunately, these problems can almost all be avoided by replacing oleylamine with formamide to form CZTS films. PMID:27059551

  15. Multi-technique surface analytical studies of automotive anti-wear films

    NASA Astrophysics Data System (ADS)

    Smith, G. C.; Bell, J. C.

    1999-04-01

    A multi-technique study of model automotive anti-wear films using SEM with quantitative electron microprobe analysis, reflection-absorption IR spectroscopy, SIMS imaging and XPS depth profiling is described. Constrained simulation of the XPS depth profiles allowed model cross-sections of the film structures to be constructed. With zinc dialkyl dithiophosphate as an anti-wear additive, the anti-wear films were found to have a thin inorganic mixed sulphide/oxide layer immediately above the Fe substrate. This formed the base for a thicker Zn-containing polyphosphate-like overlayer. Addition of detergent and dispersant to the lubricant formulation resulted in thicker, more patchy films, with a clearer differentiation between film and substrate.

  16. XPS and Raman study of slope-polished Cu(In,Ga)Se2 thin films

    NASA Astrophysics Data System (ADS)

    Beak, Gun Yeol; Jeon, Chan-Wook

    2016-05-01

    The growth of quality Cu(In,Ga)Se2 photovoltaic absorber without secondary phases is very important for improving the solar cell efficiency. Although X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy can identify the secondary phases, they provide insufficient information because of their insufficient resolution and complexity in analysis. In general, normal Raman spectroscopy is better for the analysis of secondary phases. On the other hand, the Raman signal provides information for film depths of less than 300 nm, and the Raman information cannot represent the properties of the entire film. In this regard, the authors introduce a new way of identifying secondary phases in Cu(In,Ga)Se2 films using depth Raman analysis. The as-prepared film was polished using a dimple grinder, which expanded a 2 μm thick film to approximately 1 mm, which is more than sufficient to resolve the depth distribution. Raman analysis indicated that the Cu(In,Ga)Se2 film showed different secondary phases, such as CuIn3Se5, InSe and CuSe, present in different depths of the film, whereas XPS provided complex information about the phases. Overall, the present study emphasizes that the Raman depth profile is more efficient for the identification of secondary phases in Cu(In,Ga)Se2 thin films than XPS and XRD. [Figure not available: see fulltext.

  17. Magnetization studies of embedded and coated thin films using Magneto-Optic Kerr Effect

    NASA Astrophysics Data System (ADS)

    Balasubramanian, Srinath

    The advancements made in electronic storage demand characterization of new materials and magnetic structures. The Magneto-Optic Kerr Effect (MOKE) is an interesting tool to characterize materials for usage in modern electronic storage devices such as magneto-optical drive, magnetic random access memory and spin valve devices. In this work, an attempt was made to characterize embedded and coated films using Magneto-Optic Kerr Effect technique. An experimental system was built for the measurement of Kerr rotation. Magnetization studies of PMMA (Poly(methyl methacrylate)) films embedded with iron nanoparticles and quartz films coated with hematite nanoparticles were carried out using MOKE. The embedded films exhibited weak magnetic response. For the coated films, the hysteresis loops were shifted from the origin indicating the presence of exchange bias in the system. Symmetric and asymmetric magnetization reversals were observed due to the presence of antiferromagnetic regions non-collinear with the external magnetic field. The samples with higher concentrations of nanoparticles showed dipolar interactions at relatively low fields. The coated films showed better magneto-optic response as compared to the embedded films. The exchange bias effects in the coated films makes it a candidate for various applications such as permanent magnets, magnetic recording media and stabilizers in recording heads.

  18. Structural and magnetic studies of thin Fe57 films formed by ion beam assisted deposition

    NASA Astrophysics Data System (ADS)

    Lyadov, N. M.; Bazarov, V. V.; Vagizov, F. G.; Vakhitov, I. R.; Dulov, E. N.; Kashapov, R. N.; Noskov, A. I.; Khaibullin, R. I.; Shustov, V. A.; Faizrakhmanov, I. A.

    2016-08-01

    Thin Fe57 films with the thickness of 120 nm have been prepared on glass substrates by using the ion-beam-assisted deposition technique. X-ray diffraction, electron microdiffraction and Mössbauer spectroscopy studies have shown that as-deposited films are in a stressful nanostructured state containing the nanoscaled inclusions of α-phase iron with the size of ∼10 nm. Room temperature in-plane and out-of-plane magnetization measurements confirmed the presence of the magnetic α-phase in the iron film and indicated the strong effect of residual stresses on magnetic properties of the film as well. Subsequent thermal annealing of iron films in vacuum at the temperature of 450 °C stimulates the growth of α-phase Fe crystallites with the size of up to 20 nm. However, electron microdiffraction and Mössbauer spectroscopic data have shown the partial oxidation and carbonization of the iron film during annealing. The stress disappeared after annealing of the film. The magnetic behaviour of the annealed samples was characterized by the magnetic hysteresis loop with the coercive field of ∼10 mT and the saturation magnetization decreased slightly in comparison with the α-phase Fe magnetization due to small oxidation of the film.

  19. Cultural Studies of Education: Filming Fluid Subjectivities in Indonesian Universities

    ERIC Educational Resources Information Center

    Logli, Chiara

    2016-01-01

    This article focuses on the Indonesian film "Cin(T)a," which features the interfaith and multiethnic love between two college students. I apply intergroup contact theory, critical pedagogy and grounded cosmopolitanism to the reading of the movie in order to demonstrate two key points. First, higher education is a contact zone, where…

  20. Holographic characterization of DYE-PVA films studied at 442 nm for optical elements fabrication

    NASA Astrophysics Data System (ADS)

    Couture, Jean J.

    1991-12-01

    The present work is an experimental study of the speed of hologram recording in dichromated polyvinyl alcohol films (DC-PVA) and DYE-DC-PVA films. Real-time recordings give high diffraction efficiency and low signal-to-noise ratio holograms without any chemical development. The dyes studied here are MALACHITE GREEN, EOSIN Y, and ROSE BENGAL introduced in DC-PVA films having a thickness of 60 - 62 micrometers . The best of these DYE-DC-PVA systems is a good candidate for holographic optical elements fabrication.

  1. Optical interferometry study of film formation in lubrication of sliding and/or rolling contacts

    NASA Technical Reports Server (NTRS)

    Stejskal, E. O.; Cameron, A.

    1972-01-01

    Seventeen fluids of widely varying physical properties and molecular structure were chosen for study. Film thickness and traction were measured simultaneously in point contacts by interferometry, from which a new theory of traction was proposed. Film thickness was measured in line contacts by interferometry and electrical capacitance to establish correlation between these two methods. An interferometric method for the absolute determination of refractive index in the contact zone was developed and applied to point contact fluid entrapments. Electrical capacitance was used to study the thickness and properties of the soft surface film which sometimes forms near a metal-fluid interface.

  2. Spectroscopic Ellipsometry Studies of Ag and ZnO Thin Films and Their Interfaces for Thin Film Photovoltaics

    NASA Astrophysics Data System (ADS)

    Sainju, Deepak

    Many modern optical and electronic devices, including photovoltaic devices, consist of multilayered thin film structures. Spectroscopic ellipsometry (SE) is a critically important characterization technique for such multilayers. SE can be applied to measure key parameters related to the structural, optical, and electrical properties of the components of multilayers with high accuracy and precision. One of the key advantages of this non-destructive technique is its capability of monitoring the growth dynamics of thin films in-situ and in real time with monolayer level precision. In this dissertation, the techniques of SE have been applied to study the component layer materials and structures used as back-reflectors and as the transparent contact layers in thin film photovoltaic technologies, including hydrogenated silicon (Si:H), copper indium-gallium diselenide (CIGS), and cadmium telluride (CdTe). The component layer materials, including silver and both intrinsic and doped zinc oxide, are fabricated on crystalline silicon and glass substrates using magnetron sputtering techniques. These thin films are measured in-situ and in real time as well as ex-situ by spectroscopic ellipsometry in order to extract parameters related to the structural properties, such as bulk layer thickness and surface roughness layer thickness and their time evolution, the latter information specific to real time measurements. The index of refraction and extinction coefficient or complex dielectric function of a single unknown layer can also be obtained from the measurement versus photon energy. Applying analytical expressions for these optical properties versus photon energy, parameters that describe electronic transport, such as electrical resistivity and electron scattering time, can be extracted. The SE technique is also performed as the sample is heated in order to derive the effects of annealing on the optical properties and derived electrical transport parameters, as well as the

  3. Hexametaphosphate effects on tooth surface conditioning film chemistry--in vitro and in vivo studies.

    PubMed

    Busscher, Henk J; White, Donald J; van der Mei, Henny C; Baig, Arif A; Kozak, Kathy M

    2002-01-01

    These studies compared the effects of Crest Dual Action Whitening dentifrice with sodium hexametaphosphate and control commercial dentifrices on the surface chemistry of conditioning film-coated dental enamel in vitro and in vivo. Conditioning film chemistry was studied by measurements of film thickness, ability to wet the surface/surface energy, conditioning film chemical composition and zeta potential. Laboratory and in vivo studies demonstrated that brushing and chemical-only treatment of pellicle-coated enamel surfaces produced marked changes in surface chemistry. Brushing of surfaces with all commercial dentifrices significantly reduced pellicle film quantity. Effects on non-brushed areas, of significance in the clinical situation, were different for different dentifrices. For dentifrice chemical treatments, calcium phosphate surface active builders, such as pyrophosphate and hexametaphosphate, produced stronger effects than standard (non-tartar control) dentifrices, peroxide baking soda dentifrices and dentifrices formulated with carboxylate polymers, viz. Colgate Total with copolymer. Crest Dual Action Whitening hexametaphosphate dentifrice removed more pellicle conditioning film, produced a lower zeta potential, produced the largest changes in film composition and had the greatest impact on surface free energies of the tested dentifrices. Crest Dual Action Whitening dentifrice also produced lasting changes in the reacquisition of pellicle conditioning film, as established by in vitro cycling immersion studies. Crest Dual Action Whitening dentifrice produced stronger and more lasting effects on surface film chemistry than low molecular weight pyrophosphate (Crest Tartar Control) or other polymeric-based dentifrice systems (Colgate Total). These surface chemistries may contribute to the unique clinical actions of hexametaphosphate established in recently reported, randomized clinical studies of tartar control, stain prevention and stain removal effects. PMID

  4. Swelling, ion uptake and biodegradation studies of PE film modified through radiation induced graft copolymerization

    NASA Astrophysics Data System (ADS)

    Kaur, Inderjeet; Gupta, Nitika; Kumari, Vandna

    2011-09-01

    An attempt to develop biodegradable polyethylene film grafting of mixture of hydrophilic monomers methacrylic acid (MAAc) and acrylamide (AAm) onto PE film has been carried out by preirradiation method using benzoyl peroxide as the radical initiator. Since ether linkages are susceptible to easy cleavage during degradation process, PE film was irradiated before the grafting reactions by γ-rays to introduce peroxidic linkages (PE-OO-PE) that offer sites for grafting. The effect of irradiation dose, monomer concentration, initiator concentration, temperature, time and amount of water on the grafting percent was determined. Maximum percentage of grafting of binary mixture (MAAc+AAm), (1792%) was obtained at a total concentration of binary monomer mixture=204.6×10 -2 mol/L ([MAAc]=176.5×10 -2 mol/L, [AAm]=28.1×10 -2 mol/L), [BPO]=8.3×10 -2 mol/L at 100 °C in 70 min. The grafted PE film was characterized by the Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopic (SEM) methods. Some selective properties of grafted films such as swelling studies, ion uptake and biodegradation studies have been investigated. The grafted films show good swelling in water, ion uptake studies shows promising results for desalination of brackish water and the soil burial test shows that PE film grafted with binary monomer mixture degrades up to 47% within 50 days.

  5. Vibrational studies of molecular organization in evaporated phthalocyanine thin solid films

    SciTech Connect

    Aroca, R.; Thedchanamoorthy, A.

    1995-01-01

    This report presents results on the study of the molecular organization, utilizing transmission and reflection absorption FTIR spectroscopy, of thin films of phthalocyanine complexes and metal free phthalocyanine. The spatial anisotropy was probed.

  6. Monte Carlo study on exchange bias and coercivity properties in coupled ferromagnetic/antiferromagnetic films

    NASA Astrophysics Data System (ADS)

    Jiang, Liqin; Shen, Shuangjuan; Zhang, Jian-Min; Feng, Qian; Huang, Zhigao

    2015-12-01

    Based on Monte Carlo simulation, a model consisting of an antiferromagnetic (AFM) film coupled to a ferromagnetic (FM) film is developed to study the exchange bias and coercivity phenomenon. It is suggested that exchange bias is a consequence of exchange coupling in the AFM/FM interface, and the AFM anisotropy needs to have a threshold value for the occurrence of exchange bias. Simultaneously, exchange bias and coercivity as functions of the value of anisotropy, exchange coupling and film thickness are studied. By inducing a thickness dependence of the anisotropy in FM film, the coercivity can be reduced or enhanced by choosing suitable magnetic parameters, which can better account for the discrepancies found in previous studies. The results also provide evidence for the absence of a direct correlation between coercivity and exchange bias, which is in agreement with other studies.

  7. Studies on RF sputtered (WO3)1-x (V2O5)x thin films for smart window applications

    NASA Astrophysics Data System (ADS)

    Meenakshi, M.; Sivakumar, R.; Perumal, P.; Sanjeeviraja, C.

    2016-05-01

    V2O5 doped WO3 targets for RF sputtering thin film deposition were prepared for various compositions. Thin films of (WO3)1-x (V2O5)x were deposited on to glass substrates using these targets. Structural characteristics of the prepared targets and thin films were studied using X-ray diffraction. Laser Raman studies were carried out on the thin films to confirm the compound formation.

  8. Laboratory studies of thin films representative of atmospheric sulfate aerosol

    NASA Astrophysics Data System (ADS)

    Fortin, Tara Jean

    Sulfate aerosols are present globally in both the upper troposphere and lower stratosphere. These aerosols are of great interest because they have a profound influence on Earth's radiation balance, heterogeneous chemistry, and cloud formation mechanisms throughout the atmosphere. The magnitude of these effects is ultimately determined by the size, phase, and chemical composition of the aerosols themselves. This thesis explores some of the questions that remain concerning the phase of these aerosols under atmospheric conditions and the effects of their chemical composition on heterogeneous chemistry and cloud formation mechanisms. In the upper troposphere, cirrus clouds are thought to form via the homogeneous nucleation of ice out of dilute sulfate aerosols such as ammonium sulfate ((NH4)2SO4). To investigate this, the low-temperature phase behavior of ammonium sulfate films has been studied using Fourier transform infrared (FTIR) spectroscopy. Experiments performed as a function of increasing relative humidity demonstrate that a phase transition from crystalline (NH 4)2SO4 to a metastable aqueous solution can occur at temperatures below the eutectic at 254 K. However, on occasion, direct deposition of ice from the vapor phase was observed, possibly indicating selective heterogeneous nucleation. In addition to serving as nuclei for cirrus clouds, sulfate aerosols can participate in heterogeneous reactions. The interaction of HNO3 with ammonium sulfate has been investigated as a possible loss mechanism for gas-phase HNO3 using a Knudsen cell reactor coupled with transmission FTIR spectroscopy. The results show that HNO3 reacts with solid ammonium sulfate to produce ammonium nitrate and letovicite at 203 K. Furthermore, this reaction is enhanced as a function of relative humidity from 0 to 41%. In the lower stratosphere, polar stratospheric clouds (PSCs) are important for springtime ozone depletion. The vapor deposition of ice on sulfuric acid tetrahydrate (SAT) has

  9. Understanding Film as Process of Change: A Metalanguage for the Study of Film Developed and Applied to Ingmar Bergman's "Persona" and Alan J. Pakula's "The Sterile Cuckoo."

    ERIC Educational Resources Information Center

    Koch, Christian Herbert

    This study develops and applies a way of talking about that transformation or change occurring in the mind of a film viewer as he views a film. This articulation is expressed in a metalanguage constructed along parameters of a game situation. The terminology employed in the articulation is derived from contemporary French structuralism and…

  10. Study of two different thin film coating methods in transmission laser micro-joining of thin Ti-film coated glass and polyimide for biomedical applications.

    PubMed

    Sultana, T; Georgiev, G L; Baird, R J; Auner, G W; Newaz, G; Patwa, R; Herfurth, H J

    2009-07-01

    Biomedical devices and implants require precision joining for hermetic sealing which can be achieved with low power lasers. The effect of two different thin metal film coating methods was studied in transmission laser micro-joints of titanium-coated glass and polyimide. The coating methods were cathodic arc physical vapor deposition (CA-PVD) and electron beam evaporation (EB-PVD). Titanium-coated glass joined to polyimide film can have neural electrode application. The improvement of the joint quality will be essential for robust performance of the device. Low power fiber laser (wave length = 1100 nm) was used for transmission laser micro-joining of thin titanium (Ti) film (approximately 200 nm) coated Pyrex borosilicate 7740 glass wafer (0.5 mm thick) and polyimide (Imidex) film (0.2 mm thick). Ti film acts as the coupling agent in the joining process. The Ti film deposition rate in the CA-PVD was 5-10 A/s and in the EB-PVD 1.5 A/s. The laser joint strength was measured by a lap shear test, the Ti film surfaces were analyzed by atomic force microscopy (AFM) and the lap shear tested joints were analyzed by optical microscopy and scanning electron microscopy (SEM). The film properties and the failure modes of the joints were correlated to joint strength. The CA-PVD produced around 4 times stronger laser joints than EB-PVD. The adhesion of the Ti film on glass by CA-PVD is better than that of the EB-PVD method. This is likely to be due to a higher film deposition rate and consequently higher adhesion or sticking coefficient for the CA-PVD particles arriving on the substrate compared to that of the EB-PVD film. EB-PVD shows poor laser bonding properties due to the development of thermal hotspots which occurs from film decohesion. PMID:19627828

  11. Channelling study of La1-xSrxCoO3 films on different substrates

    NASA Astrophysics Data System (ADS)

    Szilágyi, E.; Kótai, E.; Rata, D.; Németh, Z.; Vankó, G.

    2014-08-01

    The cobalt oxide system LaCoO3 and its Sr-doped child compounds have been intensively studied for decades due to their intriguing magnetic and electronic properties. Preparing thin La1-xSrxCoO3 (LSCO) films on different substrates allows for studies with a new type of perturbation, as the films are subject to substrate-dependent epitaxial strain. By choosing a proper substrate for a thin film grow, not only compressing but also tensile strain can be applied. The consequences for the fundamental physical properties are dramatic: while compressed films are metallic, as the bulk material, films under tensile strain become insulating. The goal of this work is to determine the strain tensor in LSCO films prepared on LaAlO3 and SrTiO3 substrates by pulsed laser deposition using RBS/channelling methods. Apart from the composition and defect structure of the samples, the depth dependence of the strain tensor, the cell parameters, and the volume of the unit cell are also determined. Asymmetric behaviour of the strained cell parameters is found on both substrates. This asymmetry is rather weak in the case of LSCO film grown on LaAlO3, while stronger on SrTiO3 substrate. The strain is more effective at the interface, some relaxation can be observed near to the surface.

  12. Studies of thin film nonlinear viscoelasticity for superpressure balloons

    NASA Astrophysics Data System (ADS)

    Rand, J. L.; Wakefield, D.

    2010-01-01

    In order to provide scientists with a stratospheric platform from which to conduct long duration research, a superpressure balloon is desired which will maintain a relatively constant volume for weeks at a time. The pumpkin shaped balloon has been developed by making use of the surface lobing to limit the circumferential stress and meridional tendons to carry the loads in the other direction. However, in order to prevent geometric instabilities during deployment and after pressurization, the design should eliminate as much excess material as possible while not exceeding the permissible stresses of the material. This paper will describe the behavior of the very thin membrane material selected for this application and the limits of the film in a biaxial state of stress. In addition, it is shown that the viscoelastic nature of the film will limit the stress by causing a reduced radius of curvature in the lobe of the pumpkin.

  13. FTIR and XRD study of PMMA/PCTFE blend films

    SciTech Connect

    Tripathi, S. Shripathi, T.; Tripathi, J.; Agrawal, A.; Sharma, A.

    2014-04-24

    The results are reported on solution cast PMMA-PCTFE blend films characterized using x-ray diffraction and FTIR. The nanocrystalline nature of PMMA is still seen in the blends, however, the bond modifications are clearly observed. The addition of PCTFE results in the modification in structural properties, as reflected in the XRD and FTIR spectra showing modifications in bonding as a function of PCTFE percentage.

  14. Deposition of hydroxyapatite thin films by Nd:YAG laser ablation: a microstructural study

    SciTech Connect

    Nistor, L.C.; Ghica, C.; Teodorescu, V.S.; Nistor, S.V. . E-mail: snistor@alpha1.infim.ro; Dinescu, M.; Matei, D.; Frangis, N.; Vouroutzis, N.; Liutas, C.

    2004-11-02

    Hydroxyapatite (HA) thin films has been successfully deposited by Nd:YAG laser ablation at {lambda} = 532 nm. The morphology and microstructure of the deposited layers was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution electron microscopy (HREM). Polycrystalline HA films were directly obtained with the substrate at 300 deg. C and without introducing water vapors in the deposition chamber. Electron paramagnetic resonance (EPR) measurements show that the oxygen stoichiometry in the HA films is also maintained. Depositions performed at {lambda} = 335 nm laser wavelength and 300 deg. C substrate temperature resulted in polycrystalline layers of mixed composition of HA and tricalciumphosphate (TCP)

  15. Phantom study of tear film dynamics with optical coherence tomography and maximum-likelihood estimation

    PubMed Central

    Huang, Jinxin; Lee, Kye-sung; Clarkson, Eric; Kupinski, Matthew; Maki, Kara L.; Ross, David S.; Aquavella, James V.; Rolland, Jannick P.

    2016-01-01

    In this Letter, we implement a maximum-likelihood estimator to interpret optical coherence tomography (OCT) data for the first time, based on Fourier-domain OCT and a two-interface tear film model. We use the root mean square error as a figure of merit to quantify the system performance of estimating the tear film thickness. With the methodology of task-based assessment, we study the trade-off between system imaging speed (temporal resolution of the dynamics) and the precision of the estimation. Finally, the estimator is validated with a digital tear-film dynamics phantom. PMID:23938923

  16. A Study on the Fabrication of Organic Thin Film Transistor Sensors using Gravure Printing

    NASA Astrophysics Data System (ADS)

    Hwang, Won-Jin; Hong, Jae-Min; Ju, Byeong-Kwon; Yu, Jae-Woong

    2011-12-01

    Conducting polymer TFT was fabricated with gravure printing technique using a vapor polymerization method. Polyvinyl alcohol (PVA) with excellent film forming characteristics was used as a matrix polymer. After the printing of the oxidant dispersed PVA dissolved in DI water, the vapor polymerization of the pyrrole monomer formed a thin conducting polymer film. The conductivity of the film was dependent on the concentration of the oxidant and the polymerization time. In order to be used for TFT application, the conductivity had to be reduced by controlling the various conditions. The effect of exposure to humidity on TFT signal was studied.

  17. XPS Study of Thermally Evaporated Ge-Sb-Te Amorphous Thin Films

    SciTech Connect

    Kumar, Sandeep; Singh, Digvijay; Thangaraj, R.

    2011-12-12

    Amorphous thin films were prepared from the bulk composition of Ge{sub 22}Sb{sub 22}Te{sub 56}(GST) alloy by thermal evaporation in good vacuum condition. The amorphous nature of as-deposited films was checked with x-ray diffraction (XRD) studies. X-ray photoelectron spectroscopy (XPS) has been used to determine the binding energies of the core electrons in amorphous thin GST films. In XPS, we performed the survey scan from the binding energy (BE) range from 0-1100 eV and core level spectra of Ge 3d, Sb 3d and Te 3d.

  18. Partially wetting thin liquid films: structure and dynamics studied with coherent x rays.

    PubMed

    Gutt, C; Sprung, M; Fendt, R; Madsen, A; Sinha, S K; Tolan, M

    2007-08-31

    We studied the surface structure of thin liquid films vapor deposited on solid substrates in a partial wetting situation by means of coherent x-ray scattering. No dynamics has been observed showing the absence of capillary waves on liquid films partially wetting a substrate. Instead an exponential form of the height-height correlation function has been found pointing toward a solidlike behavior of the thin liquid films at large length scales. The exact surface structure and degree of replication with the substrate depend on the deposition rate of the molecules. PMID:17931023

  19. A photoemission study of Pd ultrathin films on Pt(111)

    SciTech Connect

    Mun, Bongjin Simon; Lee, Choongman; Stamenkovic, Vojislav; Markovic, Nenad M.; Ross Jr., Philip N.

    2005-05-11

    The origin of surface core-level shift (SCLS) of Pd thin films on Pt(111) substrate is investigated. At sub-monolayer coverage of Pd thin films, the splitting of Pd 3d core level peaks indicate the contribution of both initial and final-state of photo-ionization processes while there is almost no change on valence band (VB) spectra. When the coverage of Pd reaches to single monolayer, the final-state relaxation effect on the Pd 3d vanishes and only the initial-state effect, a negative SCLS, is present. Also, the VB spectrum at Pd monolayer films shows a clear band narrowing, that is the origin of the negative SCLS at monolayer coverage. As the Pd coverage is increased to more than monolayer thickness, the Pd 3d peaks start to show the surface layer contribution from second and third layers, positive SCLS, and the VB spectrum shows even narrower band width, possibly due to the formation of surface states and strained effect of Pd adlayers on top of the first pseudomorphic layer.

  20. Electrochromic performance, wettability and optical study of copper manganese oxide thin films: Effect of annealing temperature

    NASA Astrophysics Data System (ADS)

    Falahatgar, S. S.; Ghodsi, F. E.; Tepehan, F. Z.; Tepehan, G. G.; Turhan, İ.

    2014-01-01

    In the present work, the nanostructured copper manganese oxide (CMO) thin films were prepared from acetate based sol-gel precursors and deposited on glass and indium tin oxide (ITO) substrates by dip-coating technique. The films were annealed at 300, 400 and 500 °C in ambient atmosphere. The effects of annealing temperature on structural, morphological, wettability, electrochromic and optical properties of CMO thin films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDX), water contact angle measurement (WCA), cyclic voltammetry (CV) measurements and ultraviolet-visible (UV-vis) spectrophotometery. The presence of mixed oxide phases comprising of copper manganese oxide (CuMn2O4) and manganese oxide at different annealing temperature was confirmed by XRD patterns. The results showed that the Mn3O4 phase has been changed to Mn2O3 when the annealing temperature is increased from 300 to 500 °C. The FESEM images indicated that the granular surface morphology was sensitive to annealing temperature. EDX studies indicated that the thin films contained O, Mn and Cu species. Wettability studies showed that the water contact angle of the nanostructured CMO thin films coated on glass substrates was influenced by the variation of annealing temperature and the surface nature of thin films was changed from hydrophilic to hydrophobic. The results of CVs measurement indicated that the anodic and cathodic charge density and capacitance of all CMO samples decreased with increasing scan rate in potential range of -1-1 eV. Also, the annealed CMO thin film at 500 °C showed better electrochromic performance with respect to other samples at lower scan rate. The thickness, refractive index, extinction coefficient and optical band gap of thin films coated on glass substrates were calculated from reflectance and transmittance spectra using an iterative numerical method. The optical band gap of

  1. Transdermal film-loaded finasteride microplates to enhance drug skin permeation: Two-step optimization study.

    PubMed

    Ahmed, Tarek A; El-Say, Khalid M

    2016-06-10

    The goal was to develop an optimized transdermal finasteride (FNS) film loaded with drug microplates (MIC), utilizing two-step optimization, to decrease the dosing schedule and inconsistency in gastrointestinal absorption. First; 3-level factorial design was implemented to prepare optimized FNS-MIC of minimum particle size. Second; Box-Behnken design matrix was used to develop optimized transdermal FNS-MIC film. Interaction among MIC components was studied using physicochemical characterization tools. Film components namely; hydroxypropyl methyl cellulose (X1), dimethyl sulfoxide (X2) and propylene glycol (X3) were optimized for their effects on the film thickness (Y1) and elongation percent (Y2), and for FNS steady state flux (Y3), permeability coefficient (Y4), and diffusion coefficient (Y5) following ex-vivo permeation through the rat skin. Morphological study of the optimized MIC and transdermal film was also investigated. Results revealed that stabilizer concentration and anti-solvent percent were significantly affecting MIC formulation. Optimized FNS-MIC of particle size 0.93μm was successfully prepared in which there was no interaction observed among their components. An enhancement in the aqueous solubility of FNS-MIC by more than 23% was achieved. All the studied variables, most of their interaction and quadratic effects were significantly affecting the studied variables (Y1-Y5). Morphological observation illustrated non-spherical, short rods, flakes like small plates that were homogeneously distributed in the optimized transdermal film. Ex-vivo study showed enhanced FNS permeation from film loaded MIC when compared to that contains pure drug. So, MIC is a successful technique to enhance aqueous solubility and skin permeation of poor water soluble drug especially when loaded into transdermal films. PMID:26993962

  2. A numerical study of liquid film distribution in wet natural gas pipelines

    NASA Astrophysics Data System (ADS)

    Gao, X. Q.; Zhao, Y. L.; Xu, W. W.; Guan, X. R.; Wang, J. J.; Jin, Y. H.

    2016-05-01

    The software of FLUENT was used to simulate the gas-liquid turbulent flow in wet natural gas pipeline of the Puguang gas field. The RNG k- ɛ model was used to simulate the turbulent flow, the Mixture model was used to simulate gas-liquid mixed phase, and the Eulerian wall film model was used to simulate the formation and development of liquid film. The gas phase flow field characteristics, the distribution of the axial and circumferential film thickness, and the droplet distribution in the pipeline were studied when the gas Reynolds number is 7.72 × 106(10.8m/s). The results can be concluded as followed: Liquid film distributes unevenly along the circumferential direction and mostly distributes under the pipeline wall because of gravity. The impact of the dean vortex and centrifugal force in the straight section can also influence the liquid film distribution. The wall shear stress distributions in horizontal straight pipeline is concerned with liquid membrane volatility, and consistent with the film volatility period, the wall shear stress reached the maximum value in a certain position of wave front. The influence of the wall shear stress on the film fluctuation in inclined pipeline is weakened by gravity and other factors.

  3. Study of Flux Ratio of C60 to Ar Cluster Ion for Hard DLC Film deposition

    SciTech Connect

    Miyauchi, K.; Toyoda, N.; Kanda, K.; Matsui, S.; Kitagawa, T.; Yamada, I.

    2003-08-26

    To study the influence of the flux ratio of C60 molecule to Ar cluster ion on (diamond like carbon) DLC film characteristics, DLC films deposited under various flux ratios were characterized with Raman spectrometry and Near Edge X-ray Absorption Fine Structure (NEXAFS). From results of these measurements, hard DLC films were deposited when the flux ratio of C60 to Ar cluster ion was between 0.7 and 4. Furthermore the DLC film with constant sp2 content was obtained in the range of the ratio from 0.7 to 4, which contents are lower values than that of conventional films such as RF plasma. DLC films deposited under the ratio from 1 to 4 had hardness from 40 to 45GPa. It was shown that DLC films with stable properties of low sp2 content and high hardness were formed even when the fluxes were varied from 1 to 4 during deposition. It was indicated that this process was useful in the view of industrial application.

  4. Study of the doping of thermally evaporated zinc oxide thin films with indium and indium oxide

    NASA Astrophysics Data System (ADS)

    Palimar, Sowmya; Bangera, Kasturi V.; Shivakumar, G. K.

    2013-12-01

    The present paper reports observations made on investigations carried out to study structural, optical and electrical properties of thermally evaporated ZnO thin films and their modulations on doping with metallic indium and indium oxide separately. ZnO thin film in the undoped state is found to have a very good conductivity of 90 Ω-1 cm-1 with an excellent transmittance of up to 90 % in the visible region. After doping with metallic indium, the conductivity of the film is found to be 580 Ω-1 cm-1, whereas the conductivity of indium oxide-doped films is increased up to 3.5 × 103 Ω-1 cm-1. Further, the optical band gap of the ZnO thin film is widened from 3.26 to 3.3 eV when doped with indium oxide and with metallic indium it decreases to 3.2 eV. There is no considerable change in the transmittance of the films after doping. All undoped and doped films were amorphous in nature with smooth and flat surface without significant modifications due to doping.

  5. Fluctuation microscopy studies of medium-range ordering in amorphous diamond-like carbon films.

    SciTech Connect

    Chen, X.; Sullivan, J. P.; Friedmann, T. A.; Gibson, J. M.; Cedarville Univ.; SNL

    2004-04-12

    In this letter, we report fluctuation microscopy studies of medium-range ordering in amorphous diamond-like carbon films and the effect of annealing on this ordering. Annealed and unannealed diamond-like carbon films have almost identical short-range order. Our fluctuation microscopy results, however, indicate the presence of medium range order or clustering in the films on a lateral length scale that exceeds 1 nm. Within the clustered regions, the dominant local ordering appears to be diamond-like, and graphite-like ordering is not observed. Thermal annealing up to 600 {sup o}C leads to an increase in diamond-like clustering with no onset of graphite-like clustering. However, after high temperature annealing up to 1000 {sup o}C, graphite-like clustering becomes apparent as a result of the conversion of diamond-like carbon to graphite-like carbon. The results on the as-deposited films and films annealed up to 600 {sup o}C suggest that a spontaneous medium range ordering process occurs in diamond-like carbon films during and subsequent to film growth, and this may play an important role in stress relaxation.

  6. AN EXPERIMENTAL STUDY OF THE RELATIONSHIP OF FILM MOVEMENT AND EMOTIONAL RESPONSE, AND ITS EFFECT ON LEARNING AND ATTITUDE FORMATION.

    ERIC Educational Resources Information Center

    MILLER, WILLIAM CHARLES, III

    THIS EXPERIMENTAL STUDY EXAMINED THE HYPOTHESES THAT FILM MOTION INCREASES AUDIENCE EMOTIONAL INVOLVEMENT, INCREASES POSITIVE ATTITUDE RESPONSE TO THE FILM AND DOES NOT AFFECT AUDIENCE INFORMATION RETENTION. OTHER HYPOTHESES WERE THAT THE GALVANIC SKIN RESPONSE (GSR) IS USEFUL FOR EVALUATING FILM AUDIENCE EMOTIONAL INVOLVEMENT, THAT AUDIENCE…

  7. A Raman Study of the Origin of Oxygen Defects in Hexagonal Manganite Thin Films

    NASA Astrophysics Data System (ADS)

    Chen, Xiang-Bai; Hien Nguyen Thi, Minh; Yang, In-Sang; Lee, Daesu; Noh, Tae-Won

    2012-12-01

    Oxygen defects are usually unavoidable when synthesizing oxide thin films. We study the origin of the oxygen defects in hexagonal manganite HoMnO3 epitaxial thin films through Raman scattering spectroscopy. Our results show that the oxygen defects in hexagonal HoMnO3 thin films have distinct effects on different phonon modes and on magnon scattering. Our analyses indicate that the oxygen defects in hexagonal HoMnO3 thin films mainly originate from the basal O3 and/or O4 oxygen vacancies. Furthermore, our analyses of oxygen defects predict that the Mn 3d orbitals would be more strongly hybridized with the apical O1 and/or O2 2p orbitals than the basal O3 and/or O4 2p orbitals. This prediction is consistent with our resonant Raman scattering study and earlier first-principle calculations of the electronic structures of hexagonal manganites.

  8. Study of oxygen scavenging PET-based films activated by water

    NASA Astrophysics Data System (ADS)

    Rossi, Gabriella; Scarfato, Paola; Incarnato, Loredana

    2016-05-01

    In this work an active barrier system consisting of a thin and transparent film based on polyethylene terephthalate (PET) was studied. Dynamic oxygen absorption measurements were performed at different values of relative humidity and temperature, pointing out that humidity is a key factor in activating the oxidation of the polymer sample. Moreover, the thermal and optical properties of the films were investigated and a good correlation was found between the crystallinity increase and the consequent transparency reduction occurring after the oxygen absorption.

  9. Kinetic Studies on Photodeposition of Polydiacetylene Thin Film from Solution: Preliminary Determination of the Rate Law

    NASA Technical Reports Server (NTRS)

    Paley, M. S.; Armstrong, S.; Witherow, W. K.; Frazier, D. O.

    1996-01-01

    Preliminary kinetic studies were undertaken on the photodeposition of thin films of a polydiacetylene derivative of 2-methyl-4-nitroaniline from monomer solutions onto quartz substrates. Solutions of the monomer, DAMNA, in 1,2-dichloroethane at various concentrations were irradiated at 364 nm using an argon-ion laser at several intensities. It was found that the rate of polydiacetylene (PDAMNA) film photodeposition varies linearly with UV light intensity and as the square root of monomer concentration.

  10. Nanoindentation study of niobium nitride thin films on niobium fabricated by reactive pulsed laser deposition

    SciTech Connect

    Mamun, Md Abdullah Al; Farha, Ashraf Hassan; Ufuktepe, Yüksel; Elsayed-Ali, Hani E.; Elmustafa, Abdelmageed A.

    2015-03-01

    Nanomechanical and structural properties of NbNx films deposited on single crystal Nb using pulsed laser deposition for different substrate temperature were previously investigated as a function of film/substrate crystal structure (Mamun et al. (2012) [30]). In this study we focus on the effect of laser fluences and background nitrogen pressure on the nanomechanical and structural properties of NbNx films. The crystal structure and surface morphology of the thin films were tested by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. Using nanoindentation, the investigation of the nanomechanical properties revealed that the hardness of the NbNx films was directly influenced by the laser fluence for low background nitrogen pressure, whereas the nanomechanical hardness showed no apparent correlation with laser fluence at high background nitrogen pressure. The NbNx film hardness measured at 30% film thickness increased from 14.0 ± 1.3 to 18.9 ± 2.4 GPa when the laser fluence was increased from 15 to 25 J/cm2 at 10.7 Pa N2 pressure. X-ray diffraction showed NbNx films with peaks that correspond to δ-NbN cubic and β-Nb2N hexagonal phases in addition to the δ'-NbN hexagonal phase. Finally, increasing the laser fluence resulted in NbNx films with larger grain sizes.

  11. Effect of Polymer Confinement on the Film Drainage Behavior- An RICM Study

    NASA Astrophysics Data System (ADS)

    Borkar, Suraj; Ramchandran, Arun

    2015-11-01

    We consider the dynamic effects of confinement of macromolecular liquids on the film drainage process between a drop and a flat surface. Under confinement of the order of few molecular length scales, layering and adsorption of long chains of polymers can cause entropic repulsion due to a reduced configurational freedom. This repulsive force can prevent film rupture and lead to the formation of an equilibrium film. In the current work, experiments were conducted with deformable droplets settling under gravity in a suspending liquid for Bond numbers of O(10-4) . The film drainage was studied using a microinterferometric technique namely, Reflection Interference Contrast Microscopy (RICM) for two different systems: a) silicone oil drops in paraffin oil, b) glycerol drops in silicone oil. The RICM analysis for obtaining the film drainage profiles, was done using a combination of simple cosine theory and ray tracing algorithm. For the silicone oil-paraffin oil system, the film drainage behavior observed was as expected from simulations based on thin film drainage equations. On the other hand, glycerol drops of radii smaller than 130 μm, resulted in the formation of an equilibrium film of silicone oil with an approximate thickness of 10 nm. The origin of this repulsive force is attributed to the presence of an immobilized layer of adsorbed polymer chains. Film drainage observed in glycerol drops of radii larger than 130 μm, was found to destabilize in a non-axisymmetric mode. The rapid growth of this asymmetric instability can lead to stresses (O(100 Pa)) higher than the yield stress of the adsorbed polymer layer.

  12. Silicon Carbide Epitaxial Films Studied by Atomic Force Microscopy

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Silicon carbide (SiC) holds great potential as an electronic material because of its wide band gap energy, high breakdown electric field, thermal stability, and resistance to radiation damage. Possible aerospace applications of high-temperature, high-power, or high-radiation SiC electronic devices include sensors, control electronics, and power electronics that can operate at temperatures up to 600 C and beyond. Commercially available SiC devices now include blue light-emitting diodes (LED's) and high-voltage diodes for operation up to 350 C, with other devices under development. At present, morphological defects in epitaxially grown SiC films limit their use in device applications. Research geared toward reducing the number of structural inhomogeneities can benefit from an understanding of the type and nature of problems that cause defects. The Atomic Force Microscope (AFM) has proven to be a useful tool in characterizing defects present on the surface of SiC epitaxial films. The in-house High-Temperature Integrated Electronics and Sensors (HTIES) Program at the NASA Lewis Research Center not only extended the dopant concentration range achievable in epitaxial SiC films, but it reduced the concentration of some types of defects. Advanced structural characterization using the AFM was warranted to identify the type and structure of the remaining film defects and morphological inhomogeneities. The AFM can give quantitative information on surface topography down to molecular scales. Acquired, in part, in support of the Advanced High Temperature Engine Materials Technology Program (HITEMP), the AFM had been used previously to detect partial fiber debonding in composite material cross sections. Atomic force microscopy examination of epitaxial SiC film surfaces revealed molecular-scale details of some unwanted surface features. Growth pits propagating from defects in the substrate, and hillocks due, presumably, to existing screw dislocations in the substrates, were

  13. Study of topological spin texture in B20 crystalline FeGe films

    NASA Astrophysics Data System (ADS)

    Turgut, Emrah; Park, Albert; Nguyen, Kayla; Hovden, Robert; Kourkoutis, Lena; Muller, David; Fuchs, Gregory

    The possibility of efficient and robust information storage in B20-hellimagnet systems has been attracted significant interest. Although there have been promising transmission electron microscopy (TEM) and transport studies on bulk B20 crystalline materials, the development of applications motivates study of thin-film samples grown with scalable techniques such as magnetron sputtering. Here we report transport and characterization measurements of FeGe thin films grown on Si <111>by magnetron co-sputtering. We obtain well-oriented but polycrystalline FeGe films with the B20 crystalline phase after post-growth annealing. Low temperature TEM imaging reveals that the lattice mismatch between the Si substrate and FeGe film introduces disordered helical magnetic phases. In addition, bulk susceptibility measurements of a continuous film and AMR measurements of micron-size wires indicate helical, conical, and ferromagnetic phases, but not an obvious skyrmion phase. Similar to recent reports, our measurements confirm that the observations of additional contributions to Hall effect measurements in B20 materials are not necessarily proof of magnetic skyrmion phase, and that more careful experimental studies are needed to understand thin film properties of B20 materials.

  14. Analytical study of pressure balancing in gas film seals

    NASA Technical Reports Server (NTRS)

    Zuk, J.

    1973-01-01

    The load factor is investigated for subsonic and choked flow conditions, laminar and turbulent flows, and various seal entrance conditions. Both parallel sealing surfaces and surfaces with small linear deformation were investigated. The load factor for subsonic flow depends strongly on pressure ratio; under choked flow conditions, however the load factor is found to depend more strongly on film thickness and flow entrance conditions rather than pressure ratio. The importance of generating hydrodynamic forces to keep the seal balanced under severe and multipoint operation is also discussed.

  15. Photoconductivity study of acid on Zinc phthalocyanine pyridine thin films

    NASA Astrophysics Data System (ADS)

    Singh, Sukhwinder; Saini, G. S. S.; Tripathi, S. K.

    2016-05-01

    The Metal Phthalocyanine (MPc) have attracted much interest because of chemical and high thermal stability. Molecules forming a crystal of MPc are held together by weak attractive Vander Waals forces. Organic semiconductors have π conjugate bonds which allow electrons to move via π-electron cloud overlaps. Conduction mechanisms for organic semiconductor are mainly through tunneling; hopping between localized states, mobility gaps, and phonon assisted hopping. The photo conductivity of thin films of these complexes changes when exposed to oxidizing and reducing gases. Arrhenius plot is used to find the thermal activation energy in the intrinsic region and impurity scattering region. Arrhenius plotsare used to find the thermal activation energy.

  16. Computer simulation study of waterborne two-component polyurethane film formation

    NASA Astrophysics Data System (ADS)

    Yang, Shihai

    2007-12-01

    In this thesis, a coarse-grained computer simulation model is presented to study the film growth and macroscopic morphological feature (film thickness, surface roughness and longitudinal constituent density profile) in a multi-component polymer system. The mixture consists of reactive hydrophobic (H) and polar groups (P) in a reactive aqueous solvent ( A) which is also allowed to evaporate. Characteristics of each component such as hydrophobic and polar interactions, molecular weights, and specific functionality for the covalent bonding are used to describe the waterborne two-component polyurethane (WB 2K-PUR) film growth as an example. Systematic approach is employed to study the film growth step by step starting from the mixture of its basic ingradients. Attempts are made to capture such realistic features as perceived reaction kinetics and polymerization mechanism in the model. Constituents move stochastically via the Metropolis algorithm to explore thermo-dynamic equilibration while the kinetic reactions are incorporated through flexible covalent bonding (Bond Fluctuation Model) which may arrest the growth before reaching equilibrium. Film thickness grows and its interface evolves and equilibrates as the simulation continues. Power-law dependence is found for the initial growth of film thickness (h) and surface roughness (W) with time (t), i.e., h ∝ tgamma, W ∝ tbeta, with all simulations. In addition to the study of film evolution and surface morphlogy, constituent density profiles along the longitudinal direction are also investigated to develop a deep understanding of film infra-structure as well as to track the post-reaction product distribution. Effects of parameters such as temperature, relative humidity (initial water concentration), stoichiometry (NCO:OH ratio) and reaction rate are examined specifically in these simulations. Qualitative agreements with laboratory observations are found with our simulation results.

  17. Molecular orientation in soft matter thin films studied by resonant soft X-ray reflectivity

    SciTech Connect

    Mezger, Markus; Jerome, Blandine; Kortright, Jeffrey B.; Valvidares, Manuel; Gullikson, Eric; Giglia, Angelo; Mahne, Nicola; Nannarone, Stefano

    2011-01-12

    We present a technique to study depth profiles of molecular orientation in soft matter thin films with nanometer resolution. The method is based on dichroism in resonant soft X-ray reflectivity using linear s- and p-polarization. It combines the chemical sensitivity of Near-Edge X-ray Absorption Fine Structure spectroscopy to specific molecular bonds and their orientation relative to the polarization of the incident beam with the precise depth profiling capability of X-ray reflectivity. We demonstrate these capabilities on side chain liquid crystalline polymer thin films with soft X-ray reflectivity data at the carbon K edge. Optical constants of the anisotropic refractive index ellipsoid were obtained from a quantitative analysis using the Berreman formalism. For films up to 50 nm thickness we find that the degree of orientation of the long axis exhibits no depth variation and isindependent of the film thickness.

  18. Deposition studies and coordinated characterization of MOCVD YBCO films on IBAD-MgO templates.

    SciTech Connect

    Aytug, Tolga; Paranthaman, Mariappan Parans; Heatherly Jr, Lee; Zhang, Yifei; Kim, Kyunghoon; Goyal, Amit; Maroni, V. A.; List III, Frederick Alyious

    2009-01-01

    A recently installed research metal organic chemical vapor deposition (MOCVD) system at Oak Ridge National Laboratory, provided by SuperPower, Inc., has been used to investigate the processing variables of MOCVD YBCO precursors and trends in the resulting properties. Systematic studies of film growth were carried out by optimizing deposition temperature and oxygen flow rate. Structural and superconducting properties of the YBCO films were analyzed by extensive X-ray diffraction, scanning electron microspcopy and transport measurements. The identification of intermediate phase formations after the YBCO precursor transformation was investigated with coordinated reel-to-reel Raman microprobe analysis. With the combination of these characterization techniques, an improved understanding of the growth characteristics of MOCVD YBCO films was established. Finally, critical current densities greater than 2 MA/cm2 for film thicknesses of 0.8 m have been demonstrated.

  19. Parametric study on the fuel film breakup of a cold start PFI engine

    NASA Astrophysics Data System (ADS)

    Wang, Y.-P.; Wilkinson, G. B.; Drallmeier, J. A.

    In order to provide more insight on improving the cold start fuel atomization for reducing unburned hydrocarbon emissions, the liquid fuel film breakup phenomenon in the intake valve/port region was investigated in depth for port-fuel-injected engines. Experiments were conducted using high-speed high-resolution imaging techniques to visualize the liquid film atomization and airflow patterns in an axisymmetric steady flow apparatus. The impact of valve/port seat geometry, surface roughness, and fuel properties on airflow separation and fuel film breakup were determined through a parametric study. CFD simulations were also performed with FLUENT to help understand the airflow behavior inside the intake port and valve gap region and its potential impact on fuel film atomization.

  20. Growth temperature effect on a-Si:H thin films studied by constant photocurrent method

    NASA Astrophysics Data System (ADS)

    Wadibhasme, N. A.; Dusane, R. O.

    2013-02-01

    Hydrogenated amorphous silicon (a-Si:H) thin films are synthesized by tuning different process parameters among which substrate temperature of film growth plays an important role in monitoring the device quality of the film. In this paper we have used the constant photocurrent method (CPM) to study the effect of growth temperature on the electronic and optical parameters of a-Si:H films at different photon energies. This technique primarily measures the absorption coefficient which is a result of different electronic transitions that contribute to the photocurrent. The nature of absorption coefficient changes with growth temperature that explicitly provides the information about the density of defect states present in the mid gap of a-Si:H.

  1. Ultrafast lattice response of photoexcited thin films studied by X-ray diffraction

    PubMed Central

    Herzog, Marc; Bojahr, André; Leitenberger, Wolfram; Hertwig, Andreas; Bargheer, Matias

    2014-01-01

    Using ultrafast X-ray diffraction, we study the coherent picosecond lattice dynamics of photoexcited thin films in the two limiting cases, where the photoinduced stress profile decays on a length scale larger and smaller than the film thickness. We solve a unifying analytical model of the strain propagation for acoustic impedance-matched opaque films on a semi-infinite transparent substrate, showing that the lattice dynamics essentially depend on two parameters: One for the spatial profile and one for the amplitude of the strain. We illustrate the results by comparison with high-quality ultrafast X-ray diffraction data of SrRuO3 films on SrTiO3 substrates. PMID:26798784

  2. Thin Films of a Main Chain Columnar Liquid Crystal: Studies of Structure, Phase Transitions and Alignment

    SciTech Connect

    Defaux, M.; DiMasi, E.; Vidal, Loic; Moller, Martin; Gearba, Raluca; Ivanov, Dimitri

    2009-03-22

    The structure of thin films of poly(di-n-propylsiloxane), PDPS, was studied with a combination of optical and atomic force microscopy, electron diffraction, and grazing incidence X-ray diffraction. Two different morphological features are observed in the mesomorphic films. The lamellar ribbons are composed of the chains oriented parallel to the plane of the substrate in which the reciprocal space 10 vector is vertical. The other feature with a circular symmetry, the cylindrite, contains the chains parallel to the substrate normal. The cylindrites and needles are essentially the same mesomorphic lamellae that develop differently under the conditions of confinement. The crystallization of PDPS films does not change the gross morphological features developed during the mesophase formation and mainly proceeds via epitaxial growth of the {alpha}-crystal on the parent mesophase. Spontaneous alignment of the mesomorphic PDPS films on the PTFE-rubbed substrates allows fabricating highly crystalline inorganic polymer surfaces oriented on the scale of centimeters.

  3. Computer simulation studies of confined liquid-crystal films

    NASA Astrophysics Data System (ADS)

    Wall, Greg D.; Cleaver, Douglas J.

    1997-10-01

    In this paper we present results from molecular dynamics simulations performed using a system of Gay-Berne particles confined between two substrates in a slab geometry. We use a nonseparable anisotropic molecule-substrate interaction potential and investigate weak and moderate molecule-substrate coupling strengths. We find that for both coupling strengths a well-defined, tilted molecular layer forms at each wall and that the pretilt angle and layer density are only weakly dependent on temperature as the central region is cooled through isotropiclike and nematiclike regions. The orientationally ordered fluid formed at the center of the film is tilted in sympathy with the surface layers. At low temperatures, however, where the central region adopts a layered arrangement, a sharp change is observed in the pretilt angle. This transition is more marked in the weak-coupling system where the high-temperature tilted surface layers adopt an approximately planar arrangement at low temperatures and the system resembles a bookshelf-geometry smectic film. In the moderate-coupling system, the surface layers maintain some tilt in the presence of the layered central region, leading to a smectic-stripe phase arrangement.

  4. Optical studies on electron beam evaporated Lithium Triborate films

    NASA Astrophysics Data System (ADS)

    Mohandoss, R.; Dhanuskodi, S.; Sanjeeviraja, C.

    2012-10-01

    Lithium triborate (LB3) has numerous applications in scintillator for neutron detection, laser weapon and communication. LB3 films have been prepared by electron beam evaporation technique under a pressure of 1 × 10-5 mbar on glass substrate at 323 K for 4 min. The crystallographic orientations and the lattice parameters (a = 8.55 (2); b = 5.09 (2); c = 7.39 (2) Å) were determined by powder XRD indicating the (1 1 1) preferential orientation of the film. The lower cut off wavelength at 325 nm with 75% transparency was measured from the UV-vis spectrum. The optical constants extinction coefficient (K), reflectance (R), the linear refractive index (1.34) and the optical energy band gap (˜4.0 eV) were estimated. The photoluminescence spectrum shows the emission peak in the visible region with low concentration of oxygen defects. LB3 is found to be second harmonic generation (SHG) active using a Q-switched Nd:YAG laser (1064 nm, 9 ns, 10 Hz). The nonlinear refractive index (n2 ˜ 10-16 cm2/W) and nonlinear absorption coefficient (β ˜ 10-2 cm/W) reveal (Z-scan technique) that the material has negative nonlinearity and self-focusing nature.

  5. Optical studies on electron beam evaporated lithium triborate films.

    PubMed

    Mohandoss, R; Dhanuskodi, S; Sanjeeviraja, C

    2012-10-01

    Lithium triborate (LB3) has numerous applications in scintillator for neutron detection, laser weapon and communication. LB3 films have been prepared by electron beam evaporation technique under a pressure of 1×10(-5) mbar on glass substrate at 323 K for 4 min. The crystallographic orientations and the lattice parameters (a=8.55 (2); b=5.09 (2); c=7.39 (2)Å) were determined by powder XRD indicating the (111) preferential orientation of the film. The lower cut off wavelength at 325 nm with 75% transparency was measured from the UV-vis spectrum. The optical constants extinction coefficient (K), reflectance (R), the linear refractive index (1.34) and the optical energy band gap (~4.0 eV) were estimated. The photoluminescence spectrum shows the emission peak in the visible region with low concentration of oxygen defects. LB3 is found to be second harmonic generation (SHG) active using a Q-switched Nd:YAG laser (1064 nm, 9 ns, 10 Hz). The nonlinear refractive index (n(2)~10(-16) cm(2)/W) and nonlinear absorption coefficient (β~10(-2) cm/W) reveal (Z-scan technique) that the material has negative nonlinearity and self-focusing nature. PMID:22925906

  6. Surface study of films formed on copper and brass at open circuit potential

    NASA Astrophysics Data System (ADS)

    Procaccini, R.; Schreiner, W. H.; Vázquez, M.; Ceré, S.

    2013-03-01

    The corrosion resistance of Cu-Zn alloys strongly depends on the quality of the protective passive film. This study focuses on the influence of Zn on the composition of oxide films on copper and brass (Cu77Zn21Al2) in borax 0.1 mol L-1 (pH 9.2) solution, where the solubility of copper oxides is minimal. The effect of the presence of chloride ions at low concentration (0.01 mol L-1) in the electrolyte was also evaluated. Both conditions were studied using a set of different electrochemical, optical and surface techniques such as cyclic voltammetry, differential reflectance, X-ray photoelectron spectroscopy and Raman spectroscopy. A duplex Cu2O/CuO layer forms on copper at potentials positive to the open circuit potential (OCP), while in the case of brass, zinc compounds are also incorporated to the surface film. It also became evident that a surface film can be formed on these materials even at potentials negative to the OCP. Zn(II) species are the main constituents of the films growing on brass, while copper oxides are incorporated to the surface film when approaching the OCP. The presence of chloride ions at low concentrations contributes to the dissolution of the oxo-hydroxides formed during the early stages of the aging process at open circuit potential. Also, copper chloro-compounds are formed, as shown by Raman spectroscopy for both copper and brass electrodes.

  7. Keratin film made of human hair as a nail plate model for studying drug permeation.

    PubMed

    Lusiana; Reichl, Stephan; Müller-Goymann, Christel C

    2011-08-01

    The limited source of human nail plate for studying drug permeation inspired us to develop a nail plate model made of human hair keratin. The manufacturing process consisted of keratin extraction, dialysis, molding, solvent evaporation, and curing, producing a water-resistant film. The permeability of the film was examined using three markers: sodium fluorescein, rhodamine B, and fluorescein isothiocyanate-dextran as water-soluble, lipid-soluble, and large molecule models, respectively. Bovine hoof was used for comparison. First investigation showed that keratin films (thickness 120 μm) resembled hooves (thickness 100 μm) except that these films were more permeable to rhodamine B compared with hooves (1.8-fold, p<0.01). Subsequent investigations using ungual penetration enhancers (urea, thioglycolic acid, and papain) showed that keratin films were generally more susceptible than hooves. This study revealed that the produced keratin film offers a possibility as a human nail plate substitute. However, inclusion of the penetration enhancer must be carefully interpreted. PMID:21791369

  8. Studies of ferroelectric heterostructure thin films and interfaces via in situ analytical techniques.

    SciTech Connect

    Auciello, O.; Dhote, A.; Gao, Y.; Gruen, D. M.; Im, J.; Irene, E. A.; Krauss, A. R.; Mueller, A. H.; Ramesh, R.

    1999-08-30

    The science and technology of ferroelectric thin films has experienced an explosive development during the last ten years. Low-density non-volatile ferroelectric random access memories (NVFRAMs) are now incorporated in commercial products such as ''smart cards'', while high permittivity capacitors are incorporated in cellular phones. However, substantial work is still needed to develop materials integration strategies for high-density memories. We have demonstrated that the implementation of complementary in situ characterization techniques is critical to understand film growth and interface processes, which play critical roles in film microstructure and properties. We are using uniquely integrated time of flight ion scattering and recoil spectroscopy (TOF-ISARS) and spectroscopic ellipsometry (SE) techniques to perform in situ, real-time studies of film growth processes in the high background gas pressure required to growth ferroelectric thin films. TOF-ISARS provides information on surface processes, while SE permits the investigation of buried interfaces as they are being formed. Recent studies on SrBi{sub 2}Ta{sub 2}O{sub 9} (SBT) and Ba{sub x}Sr{sub 1{minus}x}TiO{sub 3} (BST) film growth and interface processes are discussed.

  9. Structural and optical studies on antimony and zinc doped CuInS2 thin films

    NASA Astrophysics Data System (ADS)

    Ben Rabeh, M.; Chaglabou, N.; Kanzari, M.; Rezig, B.

    2009-11-01

    The influence of Zn and Sb impurities on the structural, optical and electrical properties of CuInS2 thin films on corning 7059 glass substrates was studied. Undoped and Zn or Sb doped CuInS2 thin films were deposited by thermal evaporation method and annealed in vacuum at temperature of 450 ∘C Undoped thin films were grown from CuInS2 powder using resistively heated tungsten boats. Zn species was evaporated from a thermal evaporator all together to the CuInS2 powder and Sb species was mixed in the starting powders. The amount of the Zn or Sb source was determined to be in the range 0-4 wt% molecular weight compared with the CuInS2 alloy source. The films were studied by means of X-ray diffraction (XRD), Optical reflection and transmission and resistance measurements. The films thicknesses were in the range 450-750 nm. All the Zn: CuInS2 and Sb: CuInS2 thin films have relatively high absorption coefficient between 104 cm-1 and 105 cm-1 in the visible and the near-IR spectral range. The bandgap energies are in the range of 1.472-1.589 eV for Zn: CuInS2 samples and 1.396-1.510 eV for the Sb: CuInS2 ones. The type of conductivity of these films was determined by the hot probe method. Furthermore, we found that Zn and Sb-doped CuInS2 thin films exhibit P type conductivity and we predict these species can be considered as suitable candidates for use as acceptor dopants to fabricate CuInS2-based solar cells.

  10. [Clinical and comparative study of the image quality of 3 digital radiographic systems, E-speed film and digitalized film

    PubMed

    Bóscolo, F N; de Oliveira, A E; de Almeida, S M; Haiter, C F; Haiter Neto, F

    2001-01-01

    The aim of this study was to evaluate, subjectively, the image quality of two CCD digital systems, a digital storage phosphor system, a digitized film and an E-speed film. Five objects were radiographed with 50, 60 and 70 kVp, with exposure times of 0.08, 0.13, 0.2, 0.4 and 0.8 s. In order to maximize the fidelity of the results, the dental X-ray unit employed was submitted to an evaluation so that the relation between exposure time and dose could be established. A good reproducibility was obtained. Six evaluators analyzed 375 images, using a scoring scale which ranged from 0 to 4. The results revealed different responses, indicating that the storage phosphor system had the best performance, in the various exposures employed. However, it was possible to conclude that all systems studied, except for the Sens-A-Ray, can offer images in ideal conditions for the diagnosis, as long as their latitudes are respected. PMID:11787321