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Sample records for cr-n films obtained

  1. Effect of negative bias voltage on CrN films deposited by arc ion plating. II. Film composition, structure, and properties

    SciTech Connect

    Wang Qimin; Kim, Kwang Ho

    2008-09-15

    Chromium nitride (CrN) films were deposited on Si wafers by arc ion plating at various negative bias voltages and several groups of N{sub 2}/Ar gas flux ratios and chamber gas pressures. The authors systematically investigated the influence of negative bias voltage on the synthesis, composition, microstructure, and properties of the arc ion plating (AIP) CrN films. In this article, the authors investigated the influence of negative bias voltage on the chemical composition, structure, and mechanical properties of the CrN films. The results showed that the chemical composition and phase structure of the AIP CrN films were greatly altered by application of negative bias voltage. Due to the selective resputtering effect, substoichiometric CrN films were obtained. With increase in bias voltages, the main phases in the films transformed from Cr+CrN to Cr{sub 2}N at low N{sub 2}/Ar flow ratios, whereas the films at high N{sub 2}/Ar flow ratios retained the CrN phase structure. The CrN films experienced texture transformation from CrN (200) to CrN (220), and Cr{sub 2}N (300) to Cr{sub 2}N(300)+Cr{sub 2}N(110). Increase in negative bias voltage also resulted in microstructure evolution of coarse columnar grains{yields}fine columnar grains{yields}quasiamorphous microstructure{yields}recrystallized structures. From the experimental results, the authors proposed a new structure zone model based on enhanced bombardment of incident ions by application of negative bias voltage. The influence of negative bias voltage on the microhardness and residual stresses of the films and the inherent mechanisms were also explored.

  2. Epitaxial CrN Thin Films with High Thermoelectric Figure of Merit

    SciTech Connect

    Quintela, Camilo X.; Podkaminer, Jacob P.; Luckyanova, Maria N.; Paudel, Tula R.; Thies, Eric L.; Hillsberry, Daniel A.; Tenne, Dmitri A.; Tsymbal, Evgeny Y.; Chen, Gang; Eom, Chang-Beom; Rivadulla, Francisco

    2015-04-09

    A large enhancement of the thermoelectric figure of merit is reported in single-crystalline films of CrN. The mechanism of the reduction of the lattice thermal conductivity in cubic CrN is similar to the resonant bonding in IV–VI compounds. Therefore, useful ideas from classic thermo­electrics can be applied to tune functionalities in transition metal nitrides and oxides.

  3. Epitaxial CrN thin films with high thermoelectric figure of merit.

    PubMed

    Quintela, Camilo X; Podkaminer, Jacob P; Luckyanova, Maria N; Paudel, Tula R; Thies, Eric L; Hillsberry, Daniel A; Tenne, Dmitri A; Tsymbal, Evgeny Y; Chen, Gang; Eom, Chang-Beom; Rivadulla, Francisco

    2015-05-20

    A large enhancement of the thermoelectric figure of merit is reported in single-crystalline films of CrN. The mechanism of the reduction of the lattice thermal conductivity in cubic CrN is similar to the resonant bonding in IV-VI compounds. Therefore, useful ideas from classic thermo-electrics can be applied to tune functionalities in transition metal nitrides and oxides.

  4. Structural and electrical transport studies on CrN(001) thin films

    SciTech Connect

    Swamy, G. Venkat Rakshit, R. K.; Basheed, G. A.; Maurya, K. K.; Gupta, Anurag; Kumar, Dinesh; Singh, Manju

    2016-05-23

    We report the structural and electrical transport studies on CrN{sub 1-x} (CrN) thin films with varying of N{sub 2} flow (5 – 25 SCCM) in an Argon environment of 25 SCCM. CrN thin films were grown at 600°C, in a multi chamber vacuum system at working pressure of 1×10{sup −2} Torr, under the base pressure of 1×10{sup −7} Torr. Structural and electrical transport measurements were carried out using X-ray diffraction (XRD), atomic force microscopy (AFM) and SQUID magnetometer, respectively. XRD (θ-2θ, ω-2θ, and ω) patterns on CrN thin films revealed a structural phase transition which is associated with the lattice parameter variation from 4.136 to 4.168 Å. The temperature dependent resistivity measurements on CrN/MgO(001) showed a clear change in slope at ≈280 K which confirms the magneto-structural transition of CrN from paramagnetic rock salt face-centered-cubic (FCC) to antiferromagnetic orthorhombic structure.

  5. Atomic-scale microstructure underneath nanoindentation in Al-Cr-N ceramic films

    NASA Astrophysics Data System (ADS)

    Zhuang, Chunqiang; Li, Zhipeng; Lin, Songsheng

    2015-12-01

    In this work, Al-Cr-N ceramic films deformed by nanoindentation were peeled off from silicon substrates and their atomic-scale microstructures underneath the indenter were investigated by high resolution transmission electron microscope (HR-TEM). Dislocations were formed underneath the indenter and they accumulated along nano-grain boundaries. The accumulative dislocations triggered the crack initiation along grain boundaries, and further resulted in the crack propagation. Dislocations were also observed in nano-grains on the lateral contact area. A model was proposed to describe the variation of microstructures under nanoindentation.

  6. Atomic-scale microstructure underneath nanoindentation in Al-Cr-N ceramic films

    SciTech Connect

    Zhuang, Chunqiang Li, Zhipeng; Lin, Songsheng

    2015-12-15

    In this work, Al-Cr-N ceramic films deformed by nanoindentation were peeled off from silicon substrates and their atomic-scale microstructures underneath the indenter were investigated by high resolution transmission electron microscope (HR-TEM). Dislocations were formed underneath the indenter and they accumulated along nano-grain boundaries. The accumulative dislocations triggered the crack initiation along grain boundaries, and further resulted in the crack propagation. Dislocations were also observed in nano-grains on the lateral contact area. A model was proposed to describe the variation of microstructures under nanoindentation.

  7. Crystallographic and electronic properties of AlCrN films that absorb visible light

    NASA Astrophysics Data System (ADS)

    Tatemizo, N.; Imada, S.; Miura, Y.; Nishio, K.; Isshiki, T.

    2017-05-01

    We investigate the crystallographic and electronic properties of wurtzite Cr-doped AlN (AlCrN) films (Cr ≤12.0%) that absorb visible light. We confirmed that the films consist of wurtzite columnar single crystals that are densely packed, c-axis oriented, and exhibit a random rotation along the a-axis in plane by using transmission electron microscopy. The oxidation state of Cr was found to be 3+ using Cr K-edge X-ray absorption near edge structure, which implies that Cr can be a substitute for Al3+ in AlN. The first nearest neighbor distances estimated using Cr K-edge extended X-ray absorption fine structure (EXAFS) were found to be nearly isotropic for incident light with electric fields that are parallel and perpendicular to the plane. The results of ab initio lattice relaxation calculations for the model of wurtzite Al1-xCrxN supercell where Cr replaces Al support the EXAFS results. The calculations for the model showed that additional energy bands are formed in the band gap of AlN, in which the Fermi energy (EF) is present. As expected from the calculation results, the electrical conductivity increases with increase in the Cr concentration, implying that the density of states at EF increases monotonically. From these results, we can conclude that AlCrN films are an intermediate band material with respect to their crystallographic and electric properties.

  8. Cyclic nanoindentation studies on CrN thin films prepared by RF sputtering on Zr-based metallic glass

    SciTech Connect

    Jellad, A.; Benameur, T.; Labdi, S.

    2011-01-17

    Cyclic nanoindentation tests were carried out to study the influence of the chromium nitride thin films on the mechanical properties of Zr-based metallic glass. Chromium nitride thin coatings have been deposited on Zr{sub 50}Cu{sub 40}Al{sub 10} metallic glass substrate by RF sputtering. The deposition process was done at room temperature under nitrogen reactive gas using a metallic chromium target. The CrN films have a thickness of 300 nm. Several cyclic nanoindentation measurements were conducted on CrN films and Zr{sub 50}Cu{sub 40}Al{sub 10} metallic glass substrate samples at various loading rate values. We have found that the coated metallic glass sample shows high mechanical properties such as hardness and reduced elastic modulus. Cyclic nanoindentation results show a hardening behaviour for these CrN coatings. Moreover, the CrN coated on Zr-based metallic glass was found to have a high value of resistance to crack propagation, as being analysed through the SEM pictures of the residual Vickers indentation impressions.

  9. Effect of film thickness on structural and mechanical properties of AlCrN nanocompoite thin films deposited by reactive DC magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Prakash, Ravi; Kaur, Davinder

    2016-05-01

    In this study, the influence of film thickness on the structural, surface morphology and mechanical properties of Aluminum chromium nitride (AlCrN) thin films has been successfully investigated. The AlCrN thin films were deposited on silicon (100) substrate using dc magnetron reactive co-sputtering at substrate temperature 400° C. The structural, surface morphology and mechanical properties were studied using X-ray diffraction, field-emission scanning electron microscopy and nanoindentation techniques respectively. The thickness of these thin films was controlled by varying the deposition time therefore increase in deposition time led to increase in film thickness. X-ray diffraction pattern of AlCrN thin films with different deposition time shows the presence of (100) and (200) orientations. The crystallite size varies in the range from 12.5 nm to 36.3 nm with the film thickness due to surface energy minimization with the higher film thickness. The hardness pattern of these AlCrN thin films follows Hall-Petch relation. The highest hardness 23.08 Gpa and young modulus 215.31 Gpa were achieved at lowest grain size of 12.5 nm.

  10. Effect of film thickness on structural and mechanical properties of AlCrN nanocompoite thin films deposited by reactive DC magnetron sputtering

    SciTech Connect

    Prakash, Ravi; Kaur, Davinder

    2016-05-06

    In this study, the influence of film thickness on the structural, surface morphology and mechanical properties of Aluminum chromium nitride (AlCrN) thin films has been successfully investigated. The AlCrN thin films were deposited on silicon (100) substrate using dc magnetron reactive co-sputtering at substrate temperature 400° C. The structural, surface morphology and mechanical properties were studied using X-ray diffraction, field-emission scanning electron microscopy and nanoindentation techniques respectively. The thickness of these thin films was controlled by varying the deposition time therefore increase in deposition time led to increase in film thickness. X-ray diffraction pattern of AlCrN thin films with different deposition time shows the presence of (100) and (200) orientations. The crystallite size varies in the range from 12.5 nm to 36.3 nm with the film thickness due to surface energy minimization with the higher film thickness. The hardness pattern of these AlCrN thin films follows Hall-Petch relation. The highest hardness 23.08 Gpa and young modulus 215.31 Gpa were achieved at lowest grain size of 12.5 nm.

  11. Effect of negative bias voltage on CrN films deposited by arc ion plating. I. Macroparticles filtration and film-growth characteristics

    SciTech Connect

    Wang Qimin; Kim, Kwang Ho

    2008-09-15

    Chromium nitride (CrN) films were deposited on Si wafers by arc ion plating (AIP) at various negative bias voltages and several groups of N{sub 2}/Ar gas flux ratios and chamber gas pressures. The authors systematically investigated the influence of negative bias voltage on the synthesis, composition, microstructure, and properties of the AIP CrN films. In this part (Part I), the investigations were mainly focused on the macroparticle distributions and film-growth characteristics. The results showed that macroparticle densities on the film surfaces decreased greatly by applying negative bias voltage, which can be affected by partial pressure of N{sub 2} and Ar gases. From the statistical analysis of the experimental results, they proposed a new hybrid mechanism of ion bombardment and electrical repulsion. Also, the growth of the AIP CrN films was greatly altered by applying negative bias voltage. By increasing the bias voltage, the film surfaces became much smoother and the films evolved from apparent columnar microstructures to an equiaxed microstructure. The impinging high-energy Cr ions accelerated by negative bias voltages were deemed the inherent reason for the evolution of growth characteristics.

  12. Electrical property measurements of Cr-N codoped TiO2 epitaxial thin films grown by pulsed laser deposition

    SciTech Connect

    Jacimovic, J; Gaal, R; Magrez, Arnaud; Forro, Laszlo; Regmi, Murari; Eres, Gyula

    2013-01-01

    The temperature dependent resistivity and thermo-electric power of Cr-N codoped TiO2 were compared with that of single element N and Cr doped and undoped TiO2 using epitaxial anatase thin films grown by pulsed laser deposition on (100) LaAlO3 substrates. The resistivity plots and especially the thermoelectric power data confirm that codoping is not a simple sum of single element doping. However, the negative sign of the Seebeck coefficient indicates electron dominated transport independent of doping. The narrowing distinction among the effects of different doping methods combined with increasing resistivity of the films with improving crystalline quality of TiO2 suggest that structural defects play a critical role in the doping process.

  13. Phase separation in NiCrN coatings induced by N2 addition in the gas phase: A way to generate magnetic thin films by reactive sputtering of a non-magnetic NiCr target

    NASA Astrophysics Data System (ADS)

    Luciu, I.; Duday, D.; Choquet, P.; Perigo, E. A.; Michels, A.; Wirtz, T.

    2016-12-01

    Magnetic coatings are used for a lot of applications from data storage in hard discs, spintronics and sensors. Meanwhile, magnetron sputtering is a process largely used in industry for the deposition of thin films. Unfortunately, deposition of magnetic coatings by magnetron sputtering is a difficult task due to the screening effect of the magnetic target lowering the magnetic field strength of the magnet positioned below the target, which is used to generate and trap ions in the vicinity of the target surface to be sputtered. In this work we present an efficient method to obtain soft magnetic thin films by reactive sputtering of a non-magnetic target. The aim is to recover the magnetic properties of Ni after dealloying of Ni and Cr due to the selective reactivity of Cr with the reactive nitrogen species generated during the deposition process. The effects of nitrogen content on the dealloying and DC magnetron sputtering (DCMS) deposition processes are studied here. The different chemical compositions, microstructures and magnetic properties of DCMS thin films obtained by sputtering in reactive gas mixtures with different ratios of Ar/N2 from a non-magnetic Ni-20Cr target have been determined. XPS data indicate that the increase of nitrogen content in the films has a strong influence on the NiCr phase decomposition into Ni and CrN, leading to ferromagnetic coatings due to the Ni phase. XRD results show that the obtained Ni-CrN films consist of a metallic fcc cubic Ni phase mixed with fcc cubic CrN. The lattice parameter decreases with the N2 content and reaches the theoretical value of the pure fcc-Ni, when Cr is mostly removed from the Ni-Cr phase. Dealloying of Cr from a Ni80-Cr20 solid solution is achieved in our experimental conditions and the deposition of Ni ferromagnetic coatings embedding CrN from a non-magnetic target is possible with reactive DC magnetron sputtering.

  14. Diamond film deposition on WC-Co and steel substrates with a CrN interlayer for tribological applications

    NASA Astrophysics Data System (ADS)

    Chandran, Maneesh; Hoffman, Alon

    2016-06-01

    The most renowned property of diamond is its exceptional hardness. By depositing diamond films on tungsten carbide (WC-Co) and steel substrates, the hardness of diamond can be combined with the toughness of these materials, resulting in an excellent wear resistance material for tribological applications. However, poor adhesion of diamond coating on these substrates leads to a lesser lifetime for the diamond coated tools than expected. The prime reasons for the lack of proper adhesion are the preferential formation of graphitic layer at the interface due to the catalytic activities of cobalt/iron and the interfacial residual stresses due to the mismatch in thermal expansion coefficients of diamond (1.5  ×  10-6 K-1) and WC-Co (5.2  ×  10-6 K-1) or steel (12  ×  10-6 K-1). In this review, we discuss the possibility of using a Cr-N interlayer as a diffusion barrier to prevent the catalytic activities of cobalt/iron and also to relax the interfacial residual stresses to some extent to enhance the adhesion of diamond coatings on these substrates. An overview of the most pertinent results of the last two decades, including the recent progress is introduced. We describe in detail how the Cr-N interlayer with the desired properties is fabricated. We give a concise overview of diamond deposition process, including the methods to vary the grain size from microcrystalline to nanocrystalline, which are suitable for some tribological applications. We describe in detail on surface and interface analysis, residual stress measurements, assessment adhesion strength and tribological performance of diamond coated WC-Co and steel substrates using various characterization techniques. We conclude by highlighting the current progress and future perspectives of diamond coatings on these substrates for tribological applications.

  15. Effects of 200 keV Ar-ions irradiation on the structural and optical properties of reactively sputtered CrN films

    NASA Astrophysics Data System (ADS)

    Novaković, M.; Popović, M.; Zhang, K.; Rakočević, Z.; Bibić, N.

    2016-12-01

    Modification in structural and optical properties of chromium-nitride (CrN) films induced by argon ion irradiation and thermal annealings were investigated using various experimental techniques. CrN films deposited by d. c. reactive sputtering on Si substrate were implanted with 200 keV argon ions, at fluences of 5-20 × 1015 ions/cm2. As-implanted samples were then annealed in vacuum, for 2 h at 700 °C. Rutherford backscattering spectrometry, X-ray diffraction, cross-sectional (high-resolution) transmission electron microscopy and spectroscopic ellipsometry (SE) measurements were carried out in order to study structural and optical properties of the layers. After irradiation with 200 keV Ar ions a damaged surface layer of nanocrystalline structure was generated, which extended beyond the implantation profile, but left an undamaged bottom zone. Partial loss of columnar structure observed in implanted samples was recovered after annealing at 700 °C and CrN started to decompose to Cr2N. This layer geometry determined from transmission electron microscopy was inferred in the analysis of SE data using the combined Drude and Tauc-Lorentz model, and the variation of the optical bandgap was deduced. The results are discussed on the basis of the changes induced in the microstructure. It was found that the optical properties of the layers are strongly dependent on the defects' concentration of CrN.

  16. Structural analysis of multilayer metal nitride films CrN/MoN using electron backscatter diffraction (EBSD)

    NASA Astrophysics Data System (ADS)

    Postolnyi, Bogdan; Bondar, Oleksandr; Opielak, Marek; Rogalski, Przemysław; Araújo, João. Pedro

    2016-12-01

    The electron backscatter diffraction (EBSD) analysis method was used for studying structure and properties of multilayer nitride CrN/MoN coatings fabricated by cathode arc physical vapour deposition (Arc-PVD). Samples were deposited on steel substrate with different single layer thickness from tens nanometers to 1 micron and with total thickness of coatings up to 8-13 μm. Colour grains mapping, grain size distribution profiles, pole figures and texture analyses were the main research instruments. Studying of obtained coatings was performed on specially prepared polished cross-section samples. The dependence between single layer thickness and grain size of materials, which is also changing through depth profile of the coating, was observed. In addition, it was possible to study phase composition, prevailing crystals orientation, dominant texture and grains growth. Studying of grains size, as well as other indicated parameters, is a very important task because it gives an information about grains interfaces volume, which causes changes in mechanical properties of material. Obtained results were cross-checked by X-ray diffraction analysis (XRD) where it was possible.

  17. Electronic structure of AlCrN films investigated using various photoelectron spectroscopies and ab initio calculations

    NASA Astrophysics Data System (ADS)

    Tatemizo, N.; Imada, S.; Miura, Y.; Yamane, H.; Tanaka, K.

    2017-03-01

    The valence band (VB) structures of wurtzite AlCrN (Cr concentration: 0-17.1%), which show optical absorption in the ultraviolet-visible-infrared light region, were investigated via photoelectron yield spectroscopy (PYS), x-ray/ultraviolet photoelectron spectroscopy (XPS/UPS), and ab initio density of states (DOS) calculations. An obvious photoelectron emission threshold was observed ~5.3 eV from the vacuum level for AlCrN, whereas no emission was observed for AlN in the PYS spectra. Comparisons of XPS and UPS VB spectra and the calculated DOS imply that Cr 3d states are formed both at the top of the VB and in the AlN gap. These data suggest that Cr doping could be a viable option to produce new materials with relevant energy band structures for solar photoelectric conversion.

  18. Effect of electroless nickel interlayer on wear behavior of CrN/ZrN multilayer films on Cu-alloyed ductile iron

    NASA Astrophysics Data System (ADS)

    Lin, Chung-Kwei; Hsu, Cheng-Hsun; Kung, Shu-Chi

    2013-11-01

    This study utilized electroless nickel as an interlayer, then coated nanoscale CrN/ZrN multilayer on Cu-alloyed ductile iron through cathodic arc deposition method. Morphology and structure of the coatings were analyzed by using field emission scanning electron microscopy (FESEM), X-ray diffractometer (XRD), and transmission electron microscopy (TEM). Moreover, Rockwell-C indentation, nanoindention, and ball-on-disk wear tests were all carried out to explore the properties of the coatings consisting of adhesion, hardness, elastic modulus, friction coefficient, and wear rate, respectively. The results showed that electroless nickel had a major amorphous phase while the CrN/ZrN multilayer coatings exhibited alternate nanocrystalline CrN and ZrN phases. Compared with single coating of electroless nickel or CrN/ZrN, the CrN/ZrN multilayer coatings with an electroless nickel interlayer exhibited higher hardness (31.1 GPa) and elastic modulus (256.4 GPa). Consequently, the ductile iron with the duplex coatings could be available to reduce both the friction coefficient and wear rate.

  19. In-situ SEM indentation studies of the deformation mechanisms in TiN, CrN and TiN/CrN.

    PubMed

    Rzepiejewska-Malyska, K; Parlinska-Wojtan, M; Wasmer, K; Hejduk, K; Michler, J

    2009-01-01

    In this study, the microstructure and the deformation mechanisms of TiN, CrN and multilayer TiN/CrN thin films on silicon substrates were investigated. Cross-sectional lamellas of nanoindents were prepared by focused ion beam milling to observe by transmission electron microscopy the microstructure of the as-deposited and deformed materials. TiN film exhibits nanocrystalline columns, whereas CrN shows large grains. The TiN/CrN multilayer presents microstructural features typical for both materials. A film hardness of 16.9GPa for CrN, 15.8GPa for TiN and 16.6GPa for TiN/CrN was found by the nanoindentation. Reduced modulus recorded for TiN and CrN reference coatings were 221.54 and 171.1GPa, respectively, and 218.6GPa for the multilayer coating. The deformation mechanisms were observed via in-situ scanning electron microscope nanoindentation. The TiN thin film showed short radial cracks, whereas CrN deformed through pile-up and densification of the material. For TiN/CrN multilayer pile-up and cracks were found. Transmission electron microscopy observations indicated that TiN deforms through grain boundary sliding and CrN via densification and material flow. The deformation mechanism observed in TiN/CrN multilayer was found to be a mixture of both modes.

  20. Bismuth thin films obtained by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Flores, Teresa; Arronte, Miguel; Rodriguez, Eugenio; Ponce, Luis; Alonso, J. C.; Garcia, C.; Fernandez, M.; Haro, E.

    1999-07-01

    In the present work Bi thin films were obtained by Pulsed Laser Deposition, using Nd:YAG lasers. The films were characterized by optical microscopy. Raman spectroscopy and X-rays diffraction. It was accomplished the real time spectral emission characterization of the plasma generated during the laser evaporation process. Highly oriented thin films were obtained.

  1. Exchange bias effect in NiMnSb/CrN heterostructures deposited by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Sharma Akkera, Harish; Barman, Rahul; Kaur, Navjot; Choudhary, Nitin; Kaur, Davinder

    2013-05-01

    Exchange bias has been studied in various Ni50Mn36.8Sb13.2/CrN heterostructures with different CrN thicknesses (15 nm-80 nm), grown on Si (100) substrate using magnetron sputtering. The shift in hysteresis loop up to 51 Oe from the origin was observed at 10 K for Ni-Mn-Sb film without CrN layer. On the other hand, a significant shifting of hysteresis loop was observed with antiferromagnetic (AFM) CrN layer in Ni50Mn36.8Sb13.2/CrN heterostructure. The exchange coupled 140 nm Ni50Mn36.8Sb13.2/35 nm CrN heterostructure exhibited a relatively large exchange coupling field of 148 Oe at 10 K compared to other films, which may be related to uncompensated and pinned AFM spins at FM-AFM interface and different AFM domain structures for different thicknesses of CrN layer. Further nanoindentation measurements revealed the higher values of hardness and elastic modulus of about 12.7 ± 0.38 GPa and 179.83 ± 1.24 GPa in Ni50Mn36.8Sb13.2/CrN heterostructures making them promising candidate for various multifunctional MEMS devices.

  2. The influence of thickness of CrN coating on the durability of hot forging dies

    NASA Astrophysics Data System (ADS)

    Smolik, Jerzy

    2011-06-01

    This article presents results which enabled the determination of the role of CrN coating and the influence of its thickness on the effectiveness of hybrid layer "nitrided layer / CrN coating" in the process of increasing the durability of forging dies. Dies coated with hybrid layers "nitrided layer / CrN coating" with various CrN coating thickness were — after different maintenance periods — subjected to metallographic testing, 3D shape testing and SEM analysis. Hardness distribution was also determined. The obtained results revealed that for all tested dies, independently from CrN coating thickness, the main mechanisms of their destruction was mechanical and thermal fatigue, and plastic deformation. It has been shown that the main role of CrN coating in the hybrid layer "nitrided layer / PVD coating" is to counteract a high temperature influence the source of which is forging on die material. In order to do so the CrN coating should be characterized by a considerably lower thermal conductivity coefficient to steel and low hardness so that it can efficiently resist fatigue processes in the forging process. Based on testing conducted by means of the sin 2 φ method, it was revealed that internal stresses are vitally important for CrN coating for fatigue resistance of hybrid layer "nitrided layer / CrN coating" during the forging process.

  3. Characterization of hydrogenated amorphous silicon films obtained from rice husk

    NASA Astrophysics Data System (ADS)

    Nandi, K. C.; Mukherjee, D.; Biswas, A. K.; Acharya, H. N.

    1991-08-01

    Hydrogenated amorphous silicon ( a-Si: H) films were prepared by chemical vapour deposition (CVD) of silanes generated by the acid hydrolysis of magnesium silicide (Mg 2Si) obtained from rice husk. The films were deposited at various substrate temperatures ( Ts) ranging from 430 to 520°C. The results show that the films have room temperature (294 K) dark conductivity (σ d) of the order of 10 -8 - 10 -10 (ohm-cm) -1 with single activation energy (Δ Ed) and the photoconductivity (σ ph) decreases with increase of Ts. Optical band gap ( Eopt) lies between 1.60-1.73 eV and hydrogen content ( CH) in the films is at best 8.3 at %. Au/ a-Si: H junction shows that it acts as a rectifier contact with Schottky barrier height ( VB) 0.69 eV. The films are contaminated by traces of impurities like Na, K, Al, Cl and O as revealed by secondary ion mass spectrometric (SIMS) analysis.

  4. Electrical spin injection using GaCrN in a GaN based spin light emitting diode

    SciTech Connect

    Banerjee, D.; Ganguly, S.; Saha, D.; Adari, R.; Sankaranarayan, S.; Kumar, A.; Aldhaheri, R. W.; Hussain, M. A.; Balamesh, A. S.

    2013-12-09

    We have demonstrated electrical spin-injection from GaCrN dilute magnetic semiconductor (DMS) in a GaN-based spin light emitting diode (spin-LED). The remanent in-plane magnetization of the thin-film semiconducting ferromagnet has been used for introducing the spin polarized electrons into the non-magnetic InGaN quantum well. The output circular polarization obtained from the spin-LED closely follows the normalized in-plane magnetization curve of the DMS. A saturation circular polarization of ∼2.5% is obtained at 200 K.

  5. Electric field control of ferromagnetism at room temperature in GaCrN (p-i-n) device structures

    NASA Astrophysics Data System (ADS)

    El-Masry, N. A.; Zavada, J. M.; Reynolds, J. G.; Reynolds, C. L.; Liu, Z.; Bedair, S. M.

    2017-08-01

    We have demonstrated a room temperature dilute magnetic semiconductor based on GaCrN epitaxial layers grown by metalorganic chemical vapor deposition. Saturation magnetization Ms increased when the GaCrN film is incorporated into a (p-GaN/i-GaCrN/n-GaN) device structure, due to the proximity of mediated holes present in the p-GaN layer. Zero field cooling and field cooling were measured to ascertain the absence of superparamagnetic behavior in the films. A (p-GaN/i-GaCrN/n-GaN) device structure with room temperature ferromagnetic (FM) properties that can be controlled by an external applied voltage has been fabricated. In this work, we show that the applied voltage controls the ferromagnetic properties, by biasing the (p-i-n) structure. With forward bias, ferromagnetism in the GaCrN layer was increased nearly 4 fold of the original value. Such an enhancement is due to carrier injection of holes into the Cr deep level present in the i-GaCrN layer. A "memory effect" for the FM behavior of the (p-i-n) GaCrN device structure persisted for 42 h after the voltage bias was turned off. These measurements also support that the observed ferromagnetism in the GaCrN film is not due to superparamagnetic clusters but instead is a hole-mediated phenomenon.

  6. Nanostructured Thin Films Obtained from Fischer Aminocarbene Complexes

    PubMed Central

    Lazo-Jiménez, Rosa E.; Ortega-Alfaro, M. Carmen; López-Cortés, José G.; Alvarez-Toledano, Cecilio; Chávez-Carvayar, José Á.; Ignés-Mullol, Jordi; González-Torres, Maykel; Carreón-Castro, Pilar

    2016-01-01

    The synthesis of four amphiphilic organometallic complexes with the general formula RC = M(CO)5NH(CH2)15CH3, where R is a ferrocenyl 2(a-b) or a phenyl 4(a-b) group as a donor moiety and a Fischer carbene of chromium (0) or tungsten (0) as an acceptor group, are reported. These four push-pull systems formed Langmuir (L) monolayers at the air-water interface, which were characterized by isotherms of surface pressure versus molecular area and compression/expansion cycles (hysteresis curves); Brewster angle microscopic images were also obtained. By using the Langmuir–Blodgett (LB) method, molecular monolayers were transferred onto glass substrates forming Z-type multilayers. LB films were characterized through ultraviolet-visible spectroscopy, atomic force microscopy and X-ray diffraction techniques. Results indicated that films obtained from 2b complex [(Ferrocenyl)(hexadecylamine)methylidene] pentacarbonyl tungsten (0) are the most stable and homogeneous; due to their properties, these materials may be incorporated into organic electronic devices. PMID:28773289

  7. Structure and mechanical properties of nanoscale multilayered CrN/ZrSiN coatings

    SciTech Connect

    Zhang, Z. G.; Rapaud, O.; Allain, N.; Baraket, M.; Dong, C.; Coddet, C.

    2009-07-15

    Nanocrystalline/amorphous CrN/ZrSiN multilayer coatings with a bilayer thickness ranging from 11 to 153 nm were prepared by reactive magnetron sputtering technique. The microstructure and mechanical properties of these thin films were characterized by x-ray diffraction (XRD), scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and nanoindentation. The formation of nanocrystalline CrN and nanocomposite ZiSiN in the single layer coatings was identified by XRD and FTIR. The periodic structure of the as-deposited multilayer coatings was confirmed by TEM observation. Nanoindentation tests showed that both the values of hardness (H) and reduced elastic modulus (E{sub r}) of CrN/ZrSiN multilayers remained almost constant despite varying the bilayer thickness. The multilayer coatings exhibited higher H of 30 GPa and higher resistance to plastic deformation when compared to the single layer CrN and ZrSiN coatings.

  8. Low temperature process for obtaining thin glass films

    DOEpatents

    Brinker, C.J.; Reed, S.T.

    A method for coating a substrate with a glass-like film comprises, applying to the substrate an aqueous alcoholic solution containing a polymeric network of partially hydrolyzed metal alkoxide into which network there is incorporated finely powdered glass, whereby there is achieved on the substrate a coherent and adherent initial film; and heating said film to a temperature sufficient to melt said powdered glass component, thereby converting said initial film to a final densified film.

  9. Low temperature process for obtaining thin glass films

    DOEpatents

    Brinker, C. Jeffrey; Reed, Scott T.

    1984-01-01

    A method for coating a substrate with a glass-like film comprises, applying to the substrate an aqueous alcoholic solution containing a polymeric network of partially hydrolyzed metal alkoxide into which network there is incorporated finely powdered glass, whereby there is achieved on the substrate a coherent and adherent initial film; and heating said film to a temperature sufficient to melt said powdered glass component, thereby converting said initial film to a final densified film.

  10. Highly bactericidal Ag nanoparticle films obtained by cluster beam deposition.

    PubMed

    Cavaliere, Emanuele; De Cesari, Sebastiano; Landini, Giulia; Riccobono, Eleonora; Pallecchi, Lucia; Rossolini, Gian Maria; Gavioli, Luca

    2015-08-01

    The recent emergence of bacterial pathogens resistant to most or all available antibiotics is among the major global public health problems. As indirect transmission through contaminated surfaces is a main route of dissemination for most of such pathogens, the implementation of effective antimicrobial surfaces has been advocated as a promising approach for their containment, especially in the hospital settings. However, traditional wet synthesis methods of nanoparticle-based antimicrobial materials leave a number of key points open for metal surfaces: such as adhesion to the surface and nanoparticle coalescence. Here we demonstrate an alternative route, i.e. supersonic cluster beam deposition, to obtain antimicrobial Ag nanoparticle films deposited directly on surfaces. The synthesized films are simple to produce with controlled density and thickness, are stable over time, and are shown to be highly bactericidal against major Gram positive and Gram negative bacterial pathogens, including extensively drug-resistant strains. The use of silver nanoparticle in health care is getting more widespread. The authors here describe the technique of cluster beam deposition for spraying silver on surfaces used in health care sectors. This may open a new avenue for future anti-bacterial coatings. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  11. Strain fields and electronic structure of antiferromagnetic CrN

    NASA Astrophysics Data System (ADS)

    Rojas, Tomas; Ulloa, Sergio E.

    2017-09-01

    We present a theoretical analysis of the role that strain plays on the electronic structure of chromium nitride (CrN) crystals. We use local spin-density approximation + U calculations to study the elastic constants, deformation potentials, and strain dependence of electron and hole masses near the fundamental gap. We consider the lowest energy antiferromagnetic models believed to describe CrN at low temperatures, and apply strain along different directions. We find relatively large deformation potentials for all models, and find increasing gaps for tensile strain along most directions. Most interestingly, we find that compressive strains should be able to close the relatively small indirect gap (≃100 meV) at moderate amplitudes ≃1.3 % . We also find large and anisotropic changes in the effective masses with strain, with principal axes closely related to the magnetic ordering of neighboring layers in the antiferromagnet. It would be interesting to consider the role that these effects may have on typical film growth on different substrates, and the possibility of monitoring optical and transport properties of thin films as strain is applied.

  12. Method of obtaining intensified image from developed photographic films and plates

    NASA Technical Reports Server (NTRS)

    Askins, B. S. (Inventor)

    1978-01-01

    A method is explained of obtaining intensified images from silver images on developed photographic films and plates. The steps involve converting silver of the developed film or plate to a radioactive compound by treatment with an aqueous alkaline solution of an organo-S35 compound; placing the treated film or plate in direct contact with a receiver film which is then exposed by radiation from the activated film; and developing and fixing the resulting intensified image on the receiver film.

  13. Strain fields and electronic structure of CrN

    NASA Astrophysics Data System (ADS)

    Rojas, Tomas; Ulloa, Sergio E.

    Chromium nitride (CrN) has a promising future for its resistance to corrosion and hardness, and very interesting magnetic and electronic properties. CrN presents a phase transition in which the crystal structure, magnetic ordering and electronic properties change at a (Néel) temperature ~ 280 K . Thin films from different labs exhibit different conductance behavior at low temperature. We study the unusual electronic and magnetic properties of thin layers. For that purpose we develop a tight binding Hamiltonian based on the Slater-Koster approach, and estimate the interaction between the Cr-3d and N-2p orbitals, by analyzing the band structure and comparing it with ab initio calculations performed using the LSDA+U method. These calculations show the system to behave as a semiconductor below the Néel temperature. Based on our model we calculate the effective masses and analyze the effect of strain fields in the electronic structure in order to understand the electronic behavior near the phase transition. Supported by NSF DMR-1508325.

  14. Novel doped hydroxyapatite thin films obtained by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Duta, L.; Oktar, F. N.; Stan, G. E.; Popescu-Pelin, G.; Serban, N.; Luculescu, C.; Mihailescu, I. N.

    2013-01-01

    We report on the synthesis of novel ovine and bovine derived hydroxyapatite thin films on titanium substrates by pulsed laser deposition for a new generation of implants. The calcination treatment applied to produce the hydroxyapatite powders from ovine/bovine bones was intended to induce crystallization and to prohibit the transmission of diseases. The deposited films were characterized by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. Pull-off adherence and profilometry measurements were also carried out. X-ray diffraction ascertained the polycrystalline hydroxyapatite nature of the powders and films. Fourier transform infrared spectroscopy evidenced the vibrational bands characteristic to a hydroxyapatite material slightly carbonated. The micrographs of the films showed a uniform distribution of spheroidal particulates with a mean diameter of ∼2 μm. Pull-off measurements demonstrated excellent bonding strength values between the hydroxyapatite films and the titanium substrates. Because of their physical-chemical properties and low cost fabrication from renewable resources, we think that these new coating materials could be considered as a prospective competitor to synthetic hydroxyapatite used for implantology applications.

  15. Si film separation obtained by high energy proton implantation

    SciTech Connect

    Braley, C.; Mazen, F.; Papon, A.-M.; Rieutord, F.; Charvet, A.-M.; Ntsoenzok, E.

    2012-11-06

    High energy protons implantation in the 1-1.5 MeV range can be used to detach free-standing thin silicon films with thickness between 15 and 30 {mu}m. Recently, we showed that Si orientation has a strong effect on the layer separation threshold fluence and efficiency. While complete delamination of (111)Si films is achieved, (100)Si films separation is more challenging due to blistering phenomena or partial separation of the implanted layer. In this work, we study the fracture mechanism in (100) and (111)Si after high energy implantation in order to understand the origin of such a behavior. We notably point out that fracture precursor defects, i.e. the platelets, preferentially form on (111) planes, as a consequence of the low strain level in the damaged region in our implantation conditions. Fracture therefore propagates easily in (111)Si, while it requires higher fluence to overcome unfavorable precursors orientation and propagate in (100)Si.

  16. Polymer multilayer films obtained by electrochemically catalyzed click chemistry.

    PubMed

    Rydzek, Gaulthier; Thomann, Jean-Sébastien; Ben Ameur, Nejla; Jierry, Loïc; Mésini, Philippe; Ponche, Arnaud; Contal, Christophe; El Haitami, Alae E; Voegel, Jean-Claude; Senger, Bernard; Schaaf, Pierre; Frisch, Benoît; Boulmedais, Fouzia

    2010-02-16

    We report the covalent layer-by-layer construction of polyelectrolyte multilayer (PEM) films by using an efficient electrochemically triggered Sharpless click reaction. The click reaction is catalyzed by Cu(I) which is generated in situ from Cu(II) (originating from the dissolution of CuSO(4)) at the electrode constituting the substrate of the film. The film buildup can be controlled by the application of a mild potential inducing the reduction of Cu(II) to Cu(I) in the absence of any reducing agent or any ligand. The experiments were carried out in an electrochemical quartz crystal microbalance cell which allows both to apply a controlled potential on a gold electrode and to follow the mass deposited on the electrode through the quartz crystal microbalance. Poly(acrylic acid) (PAA) modified with either alkyne (PAA(Alk)) or azide (PAA(Az)) functions grafted onto the PAA backbone through ethylene glycol arms were used to build the PEM films. Construction takes place on gold electrodes whose potentials are more negative than a critical value, which lies between -70 and -150 mV vs Ag/AgCl (KCl sat.) reference electrode. The film thickness increment per bilayer appears independent of the applied voltage as long as it is more negative than the critical potential, but it depends upon Cu(II) and polyelectrolyte concentrations in solution and upon the reduction time of Cu(II) during each deposition step. An increase of any of these latter parameters leads to an increase of the mass deposited per layer. For given buildup conditions, the construction levels off after a given number of deposition steps which increases with the Cu(II) concentration and/or the Cu(II) reduction time. A model based on the diffusion of Cu(II) and Cu(I) ions through the film and the dynamics of the polyelectrolyte anchoring on the film, during the reduction period of Cu(II), is proposed to explain the major buildup features.

  17. Optical properties of thin films of CdSe obtained by spray pyrolisis

    NASA Astrophysics Data System (ADS)

    Gonzalez, A. M. P.; Tepantlan, C. S.; Carrillo, F. R.

    2006-06-01

    In this paper the optical properties of CdSe thin films obtained by spray pyrolisis are presented. The films are prepared by Sodium Selenosulphate (Na2SSeO3) and Cadmium Chloride (CdC12) mixing in aqueous environment. Optical parameters of the films (refractive index, absorption coefficient and optical bangap) were calculated from transmittance spectra. The obtained values of the optical bangap are compared with the result obtained by other deposition methods.

  18. Method of depositing a carbon film on a substrate and products obtained thereby

    SciTech Connect

    Lewin, G.; Nir, D.

    1984-12-04

    There is disclosed a method for depositing a diamond or diamond-like carbon film on at least one substrate employing a hydrocarbon gas and at least one gas which preferentially removes by chemical sputtering other forms of carbon, especially graphite from said film to thereby obtain useful carbon film coated products.

  19. XPS investigations of tribofilms formed on CrN coatings

    NASA Astrophysics Data System (ADS)

    Mandrino, Djordje; Podgornik, Bojan

    2017-02-01

    Action of lubrication additives in the case of uncoated steel surfaces, including the type and mechanism of tribofilm formation is well known and understood. However, contact type of tribofilms which might form under the tribological contact between CrN coated surfaces, remains more or less unexplored. The aim of this investigation was to study the type of tribofilms formed on the CrN coated steel samples subjected to lubricated reciprocating sliding contact under different contact conditions Contact surface and tribofilms formed were studied by X-ray Photoelectron Spectroscopy (XPS). Sample surfaces were first imaged by Scanning Electron Microscopy (SEM) to determine areas of tribofilm formation as well as areas not affected by tribological contact. In these areas survey and high resolution (HR) XPS measurements were performed to obtain information about surface chemistry and oxidation states of the constituent elements. It was found that differences between different samples, observed by the XPS measurements, may reflect differences in chemistry of tribofilms formed under different contact conditions.

  20. Sealing of hard CrN and DLC coatings with atomic layer deposition.

    PubMed

    Härkönen, Emma; Kolev, Ivan; Díaz, Belén; Swiatowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe; Fenker, Martin; Toth, Lajos; Radnoczi, György; Vehkamäki, Marko; Ritala, Mikko

    2014-02-12

    Atomic layer deposition (ALD) is a thin film deposition technique that is based on alternating and saturating surface reactions of two or more gaseous precursors. The excellent conformality of ALD thin films can be exploited for sealing defects in coatings made by other techniques. Here the corrosion protection properties of hard CrN and diamond-like carbon (DLC) coatings on low alloy steel were improved by ALD sealing with 50 nm thick layers consisting of Al2O3 and Ta2O5 nanolaminates or mixtures. In cross sectional images the ALD layers were found to follow the surface morphology of the CrN coatings uniformly. Furthermore, ALD growth into the pinholes of the CrN coating was verified. In electrochemical measurements the ALD sealing was found to decrease the current density of the CrN coated steel by over 2 orders of magnitude. The neutral salt spray (NSS) durability was also improved: on the best samples the appearance of corrosion spots was delayed from 2 to 168 h. On DLC coatings the adhesion of the ALD sealing layers was weaker, but still clear improvement in NSS durability was achieved indicating sealing of the pinholes.

  1. Fibrillar films obtained from sodium soap fibers and polyelectrolyte multilayers.

    PubMed

    Zawko, Scott A; Schmidt, Christine E

    2011-08-01

    An objective of tissue engineering is to create synthetic polymer scaffolds with a fibrillar microstructure similar to the extracellular matrix. Here, we present a novel method for creating polymer fibers using the layer-by-layer method and sacrificial templates composed of sodium soap fibers. Soap fibers were prepared from neutralized fatty acids using a sodium chloride crystal dissolution method. Polyelectrolyte multilayers (PEMs) of polystyrene sulfonate and polyallylamine hydrochloride were deposited onto the soap fibers, crosslinked with glutaraldehyde, and then the soap fibers were leached with warm water and ethanol. The morphology of the resulting PEM structures was a dense network of fibers surrounded by a nonfibrillar matrix. Microscopy revealed that the PEM fibers were solid structures, presumably composed of polyelectrolytes complexed with residual fatty acids. These fibrillar PEM films were found to support the attachment of human dermal fibroblasts. Copyright © 2011 Wiley Periodicals, Inc.

  2. Thin-film TiPbO3 varistors obtained by two-source magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Ziaja, J.; Lewandowski, M.

    2016-02-01

    The paper presents the method of obtaining thin films of TiPbO3 by two-source magnetron sputtering DC-M. The films were obtained in a reactive process of sputtering metallic targets of titanium (Ti) and lead (Pb). The research involved the impact of the time of sputtering of the respective targets on voltage-dependent resistance of the obtained films for different power conditions, pressures of process gases and the powers provided on the targets. The obtained nonlinearity coefficients and the current-voltage I(U) characteristics were within the following range.

  3. Surface morphology of ultrathin graphene oxide films obtained by the SAW atomization

    NASA Astrophysics Data System (ADS)

    Balachova, Olga V.; Balashov, Sergey M.; Costa, Carlos A. R.; Pavani Filho, A.

    2015-08-01

    Lately, graphene oxide (GO) thin films have attracted much attention: they can be used as humidity-sensitive coatings in the surface acoustic wave (SAW) sensors; being functionalized, they can be used in optoelectronic or biodevices, etc. In this research we study surface morphology of small-area thin GO films obtained on Si and quartz substrates by deposition of very small amounts of H2O-GO aerosols produced by the SAW atomizer. An important feature of this method is the ability to work with submicrovolumes of liquids during deposition that provides relatively good control over the film thickness and quality, in particular, minimization of the coffee ring effect. The obtained films were examined using AFM and electron microscopy. Image analysis showed that the films consist of GO sheets of different geometry and sizes and may form discrete or continuous coatings at the surface of the substrates with the minimum thickness of 1.0-1.8 nm which corresponds to one or two monolayers of GO. The thickness and quality of the deposited films depend on the parameters of the SAW atomization (number of atomized droplets, a volume of the initial droplet, etc.) and on sample surface preparation (activation in oxygen plasma). We discuss the structure of the obtained films, uniformity and the surface coverage as a function of parameters of the film deposition process and sample preparation. Qualitative analysis of adhesion of GO films is made by rinsing the samples in DI water and subsequent evaluation of morphology of the remained films.

  4. Ag surface diffusion and out-of-bulk segregation in CrN-Ag nano-composite coatings.

    PubMed

    Incerti, L; Rota, A; Ballestrazzi, A; Gualtieri, E; Valeri, S

    2011-10-01

    CrN-Ag nanocomposite coatings are deposited on Si(100) wafers and 20MnCr5 steel disks in a mixed Ar+N2 atmosphere by reactive magnetron sputtering. Structure, composition and morphology were investigated by Scanning Electron Microscopy (SEM), Auger Electron Spectroscopy (AES), X-ray Photoemission Spectroscopy (XPS), X-ray Diffraction (XRD) and Focused Ion Beam (FIB) cross sectional analysis. The as deposited film matrix is mainly composed by CrN phase (78%), but a relevant part (28%) is composed by Cr2N. Ag agglomerates in the CrN matrix forming elongated grains 200-400 nm wide and 50-100 nm high, which extends on the top of CrN columns. At the surface Ag aggregates into two different structures: large tetrahedral crystalline clusters, with typical dimension ranging from 200 to 500 nm, and smaller Ag nanoparticles with diameter of 15-25 nm. The annealing in N2 atmosphere up to 500 degrees C does not affect size and distribution of the Ag grains in the sub-surface region, while it induces a size increase of the bigger Ag clusters on the surface, mainly related to Ag surface diffusion and clusters coalescence. Annealing at higher temperature leads to an evident Ag out-of-bulk segregation, generating Ag depleted voids in the near-surface region, and further increasing of the Ag clusters size at the surface. Tribological tests on as deposited CrN-Ag film reveal a coefficient of friction against a steel ball reduced with respect to CrN film, probably related to the presence of Ag which acts as solid lubricant, but the coating is removed after a very short sliding distance. The poor mechanical properties of the realized Ag-based coatings are confirmed by lower hardness and Young modulus values with respect to pure CrN.

  5. Experimental invalidation of phase-transition-induced elastic softening in CrN

    NASA Astrophysics Data System (ADS)

    Wang, Shanmin; Yu, Xiaohui; Zhang, Jianzhong; Chen, Miao; Zhu, Jinlong; Wang, Liping; He, Duanwei; Lin, Zhijun; Zhang, Ruifeng; Leinenweber, Kurt; Zhao, Yusheng

    2012-08-01

    We report experimental results of phase stability and incompressibility of CrN. The obtained bulk moduli for cubic and orthorhombic CrN are 257 and 262 GPa, respectively. These results invalidate the conclusion of phase-transition-induced elastic softening recently reported based on nonmagnetic simulations for cubic CrN [Nature Mater.NMAACR1476-112210.1038/nmat2549 8, 947 (2009)]. On the other hand, they provide the only experimental evidence to support the computational models involving the local magnetic moment of Cr atoms [Nature Mater.NMAACR1476-112210.1038/nmat2722 9, 283 (2010)], indicating that atomic spin has a profound influence on the material's elastic properties. We also demonstrate that nonstoichiometry in CrNx has strong effects on its structural stability.

  6. Enhanced wear and fatigue properties of Ti-6Al-4V alloy modified by plasma carburizing/CrN coating.

    PubMed

    Park, Y G; Wey, M Y; Hong, S I

    2007-05-01

    In this study, a newly developed duplex coating method incorporating plasma carburization and CrN coating was applied to Ti-6Al-4V and its effects on the wear resistance and fatigue life were investigated. The carburized layer with approximately150 microm in depth and CrN coating film with 7.5 microm in thickness were formed after duplex coating. Hard carbide particles such as TiC And V(4)C(3) were formed in the carburized layer. XRD diffraction pattern analysis revealed that CrN film had predominant [111] and [200] textures. The hardness (Hv) was significantly improved up to about 1,960 after duplex coating while the hardness value of original Ti-6Al-4V was 402. The threshold load for the modification and/or failure of CrN coating was measured to be 32 N using the acoustic emission technique. The wear resistance and fatigue life of duplex-coated Ti-6Al-4V improved significantly compared to those of un-treated specimen. The enhanced wear resistance can be attributed to the excellent adhesion and improved hardness of CrN coating film for the duplex-coated Ti-6Al-4V. The initiation of fatigue cracks is likely to be retarded by the presence of hard and strong layers on the surface, resulting in the enhanced fatigue life.

  7. Erbium oxide thin films on Si(100) obtained by laser ablation and electron beam evaporation

    NASA Astrophysics Data System (ADS)

    Queralt, X.; Ferrater, C.; Sánchez, F.; Aguiar, R.; Palau, J.; Varela, M.

    1995-02-01

    Erbium oxide thin films have been obtained by laser ablation and electron beam evaporation techniques on Si(100) substrates. The samples were grown under different conditions of oxygen atmosphere and substrate temperature without any oxidation process after deposition. The crystal structure has been studied by X-ray diffraction. Films obtained by laser ablation are highly textured in the [ hhh] direction, although this depends on the conditions of oxygen pressure and substrate temperature. In order to study the depth composition profile of the thin films and the interdiffusion of erbium metal and oxygen towards the silicon substrates, X-ray photoelectron spectroscopy analyses have been carried out.

  8. Elaboration, characterization of CrN- based coatings

    SciTech Connect

    Tlili, B.; Nouveau, C.; Guillemot, G.

    2011-01-17

    Cr, CrN and CrAlN monolayers were synthesized by RF dual magnetron sputtering on AISI4140 steel and silicon substrates at 200 deg. C. Multilayers coatings based on the three mono-layers such as CrN/CrAlN and Cr/CrN/CrAlN were also synthesized only on Si. The physico-chemical and mechanical properties of the layers were determined by AFM, SEM+WDS, stress, roughness and nanoindentation measurements. The influence of the thickness on the mechanical properties of the monolayers stresses has been studied and as a consequence we compared the mono and multilayers stress state.

  9. Photoconductive WS 2 thin films obtained from a multilayer Ni/W/S…W/S structure

    NASA Astrophysics Data System (ADS)

    Ouerfelli, J.; Bernède, J. C.; Khelil, A.; Pouzet, J.

    1997-11-01

    Photoconductive WS 2 thin films were obtained by post annealing treatments of W/S/W…S/W/S thin layers sequentially deposited on a mica substrate coated with a thin Ni layer. After deposition by sputtering of W layers and evaporation of S layers, the samples were post annealed at 1073 K for half an hour under an argon flow. The films obtained were crystallized in the hexagonal structure expected. However there is a tungsten excess and, at the surface of the films, this tungsten is oxidized. This surface oxide is reduced by annealing of the samples under sulphur atmosphere. In order to sublimate the sulphur condensed at the surface of the films during the cooling of the samples, at the end of the process, the films were post annealed under vacuum. The films obtained are stochiometric, their surface oxidation has nearly disappeared and they are textured with the c axis perpendicular to the plane of the substrate. These films are highly photoconductive. The room temperature conductivity is about 0.5 (Ω cm) -1 which is of the same order of magnitude than the WS 2 single crystals.

  10. Conductive Cu-TiO2 thin films obtained via MOCVD

    NASA Astrophysics Data System (ADS)

    Alvarez Y Quintavalle, F.; Battiston, G. A.; Casellato, U.; Fregona, D.; Gerbasi, R.; Loro, F.

    2002-06-01

    Growths of nanophased Cu, CuO, Cu-TiO2 and Cu2O-TiO2 thin films were performed by using titanium tetraisopropoxide Ti(OiPr)4, and copper(II)acetylacetonatehydrate Cu(acac)2.H2O in the temperature range 275- 370 °C. The composite Cu-TiO2 with very low percent of titanium dioxide (TiO2<5%) can be an alternative procedure to obtain well adherent, smooth and well connected Cu films. Cu2O-TiO2 were obtained by annealing of Cu-TiO2 thin films. Cu2O in a TiO2 matrix remains unaltered after repeated thermal treatments when the Cu:Ti metal ratio is equal or less than 15:1. The films exhibited semiconductor characteristics with a moderate transparency, 40-60% in the visible region.

  11. Utilization of iron oxide film obtained by CVD process as catalyst to carbon nanotubes growth

    SciTech Connect

    Schnitzler, Mariane C.; Zarbin, Aldo J.G.

    2009-10-15

    Thin films of Fe{sub 2}O{sub 3} were obtained on silica glass substrates through the thermal decomposition of ferrocene in air. These films were characterized by Raman spectroscopy and X-ray diffractometry (XRD), and subsequently used as catalyst on the growth of carbon nanotubes, using benzene or a benzene solution of [Fe{sub 3}(CO){sub 12}] as precursor. A great amount of a black powder was obtained as product, identified as multi-walled carbon nanotubes by XRD, Raman spectroscopy and transmission electron microscopy. The carbon nanotubes formed through the pyrolysis of the [Fe{sub 3}(CO){sub 12}] solution were identified as structurally better than the one obtained by the pyrolysis of pristine benzene. - Graphical abstract: Thin films of Fe{sub 2}O{sub 3} were obtained on silica glass substrates through the thermal decomposition of ferrocene in air, and subsequently used as catalyst on the growth of carbon nanotubes.

  12. Nanocharacterization of Titanium Nitride Thin Films Obtained by Reactive Magnetron Sputtering

    NASA Astrophysics Data System (ADS)

    Merie, Violeta Valentina; Pustan, Marius Sorin; Bîrleanu, Corina; Negrea, Gavril

    2015-05-01

    Titanium nitride thin films are used in applications such as tribological layers for cutting tools, coating of some medical devices (scalpel blades, prosthesis, implants, etc.), sensors, electrodes for bioelectronics, microelectronics, diffusion barrier, bio-micro-electromechanical systems, and so on. This work is a comparative study concerning the influence of substrate temperature on some mechanical and tribological characteristics of titanium nitride thin films. The researched thin films were obtained by the reactive magnetron sputtering method. The experiments employed two kinds of substrates: a steel substrate and a silicon one. The elaboration of titanium nitride thin films was done at two temperatures. First, when the substrates were at room temperature, and second, when the substrates were previously heated at 250°C. The temperature of 250°C was kept constant during the deposition of the films. The samples were then investigated by atomic force microscopy in order to establish their mechanical and tribological properties. The nanohardness, Young's modulus, roughness, and friction force were some of the determined characteristics. The results demonstrated that the substrate which was previously heated at 250°C led to the obtaining of more adherent titanium nitride thin films than the substrate used at room temperature. The preheating of both substrates determined the decrease of thin films roughness. The friction force, nanohardness and Young's modulus of the tested samples increased when the substrates were preheated at 250°C.

  13. Cyclic Nanoindentation and Finite Element Analysis of Ti/TiN and CrN Nanocoatings on Zr-Based Metallic Glasses Mechanical Performance

    NASA Astrophysics Data System (ADS)

    Tekaya, A.; Ghulman, H. A.; Benameur, T.; Labdi, S.

    2014-12-01

    Cyclic depth-sensing nanoindentation tests are carried out to unravel the effect of monolithic and multilayer thin coatings on load-bearing capacity and stress distribution in the coating-Zr-based metallic glass systems. Thin films of TiN, CrN, and Ti/TiN multilayer, having thickness of 300 nm, are deposited on Zr60Ni10Cu20Al10 and Zr50Cu40Al10 metallic glasses by RF sputtering technique. Strain softening occurs over several cycles in Zr-based metallic glasses, CrN, and TiN films as evidenced by a disparity between the unloading and reloading sequences. However, the cyclic nanoindentation of Ti/TiN multilayer coating results in a hysteresis loop in the load-depth profiles, and this event depends on the number of cycles and the loading rates. AFM and SEM characterization of remnant imprints revealed microcraks and crack-like shear bands in nanocoatings and Zr-based metallic glasses, respectively. Based on shear-fracture driven plastic flow of the coatings, a modified cavity model is used to determine the shear stress evolution as a function of penetration depth. The finite-element simulations predicted the stress distribution beneath the indenter and are well consistent with the evolving trend of shear stress obtained from experiments.

  14. Quantifying Cutting and Wearing Behaviors of TiN- and CrN-Coated AISI 1070 Steel

    PubMed Central

    Cakan, Ahmet; Ozkaner, Vedat; Yildirim, Mustafa M.

    2008-01-01

    Hard coatings such as titanium nitride (TiN) and chromium nitride (CrN) are widely used in cutting and forming tools against wear and corrosion. In the present study, hard coating films were deposited onto AISI 1070 steels by a cathodic arc evaporation plating (CAVP) technique. These samples were subjected to wear in a conventional lathe for investigating the tribological behaviour of coating structure, and prenitrided subsurface composition was characterized using scanning electron microscopy (SEM), line scan analyses and X-ray diffraction (XRD). The wear properties of TiN- and CrN-coated samples were determined using an on-line monitoring system. The results show that TiN-coated samples demonstrate higher wear resistance than CrN-coated samples. PMID:27873912

  15. InN nanorods prepared with CrN nanoislands by plasma-assisted molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Liu, Kuang-Wei; Chang, Shoou-Jinn; Young, Sheng-Joue; Hsueh, Tao-Hung; Hung, Hung; Mai, Yu-Chun; Wang, Shih-Ming; Chen, Kuan-Jen; Wu, Ya-Ling; Chen, Yue-Zhang

    2011-07-01

    The authors report the influence of CrN nanoisland inserted on growth of baseball-bat InN nanorods by plasma-assisted molecular beam epitaxy under In-rich conditions. By inserting CrN nanoislands between AlN nucleation layer and the Si (111) substrate, it was found that we could reduce strain form Si by inserting CrN nanoisland, FWHM of the x-ray rocking curve measured from InN nanorods from 3,299 reduced to 2,115 arcsec. It is due to the larger strain from lattice miss-match of the film-like InN structure; however, the strain from lattice miss-match was obvious reduced owing to CrN nanoisland inserted. The TEM images confirmed the CrN structures and In droplets dissociation from InN, by these results, we can speculate the growth mechanism of baseball-bat-like InN nanorods.

  16. Nanocharacterization of titanium nitride thin films obtained by reactive magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Merie, V. V.; Pustan, M. S.; Bîrleanu, C.; Negrea, G.

    2014-08-01

    Titanium nitride thin films are used in applications such as tribological layers for cutting tools, coating of some medical devices (scalpel blades, prosthesis, implants etc.), sensors, electrodes for bioelectronics, microelectronics, diffusion barrier, bio-microelectromechanical systems (Bio-MEMS) and so on. This work is a comparative study concerning the influence of substrate temperature on some mechanical and tribological characteristics of titanium nitride thin films. The researched thin films were obtained by reactive magnetron sputtering method. The experiments employed two kinds of substrates: a steel substrate and a silicon one. The elaboration of titanium nitride thin films was done at two temperatures. First, the obtaining was realized when the substrates were at room temperature, and second, the obtaining was realized when the substrates were previously heated at 250 °C. The elaborated samples were then investigated by atomic force microscopy in order to establish their mechanical and tribological properties. The nanohardness, roughness, friction force are some of the determined characteristics. The results marked out that the substrate which was previously heated at 250 °C led to the obtaining of more adherent titanium nitride thin films than the substrate used at room temperature.

  17. Drude's Model Optical Parameters and the Color of TiNx Films Obtained Through Reflectivity Measurements

    NASA Astrophysics Data System (ADS)

    Alves, L. A.; Sagás, J. C.; Damião, A. J.; Fontana, L. C.

    2015-02-01

    Titanium nitride (TiN) has been applied as decorative coating due to its high reflectivity and goldish color, having high hardness and wear resistance. In the present work, TiNx films were deposited by grid-assisted magnetron sputtering. The color and reflectivity were investigated by spectrophotometry as a function of the working gas ratio N2/Ar used during films deposition. The crystalline phases were identified by X-ray diffraction pattern (XRD). The TiNx plasma frequency ( ω p) and the relaxation time ( τ) were determined by fitting the experimental reflectivity curves, according to the Drude model. The color parameters obtained by the CieLab method were used to compare TiNx films with gold film.

  18. Conducting, transparent and flexible substrates obtained from interfacial thin films of double-walled carbon nanotubes.

    PubMed

    Souza, Victor H R; Flahaut, Emmanuel; Zarbin, Aldo J G

    2017-09-15

    Conducting and transparent interfacial thin films have been prepared from double-walled carbon nanotubes (DWCNT) and further deposited over glass and plastic (polyethylene terephtalate-PET) substrates. The morphology, vibrational structure as well as the optical and electrical properties have been evaluated. The influence of the DWCNT purifying treatment, the amount of carbon nanotubes used to prepare the thin films, and the annealing of the films at different temperatures has been evaluated to optimize both electrical and optical properties. Values of sheet resistance ranging from 0.53 to 27.8 kΩ □(-1) and transmittance at 550nm from 59 to 90% have been achieved. Similar behavior obtained for films deposited on PET or glass substrates indicate a good reproducibility of the method, besides the high potential for further applications on flexible devices. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Enhanced Corrosion Resistance of PVD-CrN Coatings by ALD Sealing Layers.

    PubMed

    Wan; Zhang, Teng Fei; Ding, Ji Cheng; Kim, Chang-Min; Park, So-Won; Yang, Yang; Kim, Kwang-Ho; Kwon, Se-Hun

    2017-12-01

    Multilayered hard coatings with a CrN matrix and an Al2O3, TiO2, or nanolaminate-Al2O3/TiO2 sealing layer were designed by a hybrid deposition process combined with physical vapor deposition (PVD) and atomic layer deposition (ALD). The strategy was to utilize ALD thin films as pinhole-free barriers to seal the intrinsic defects to protect the CrN matrix. The influences of the different sealing layers added in the coatings on the microstructure, surface roughness, and corrosion behaviors were investigated. The results indicated that the sealing layer added by ALD significantly decreased the average grain size and improved the corrosion resistance of the CrN coatings. The insertion of the nanolaminate-Al2O3/TiO2 sealing layers resulted in a further increase in corrosion resistance, which was attributed to the synergistic effect of Al2O3 and TiO2, both acting as excellent passivation barriers to the diffusion of corrosive substances.

  20. Obtainment and partial characterization of biodegradable gelatin films with tannic acid, bentonite and glycerol.

    PubMed

    Ortiz-Zarama, Maria A; Jiménez-Aparicio, Antonio R; Solorza-Feria, Javier

    2016-08-01

    Research studies concerning the overall effect of the addition of plasticizers, cross-linking and strengthening agents in gelatin film-forming mixtures are very scarce. Also, there are no studies focused on the interactions among their individual components, or showing what sort of effects they might cause all together. A gelatin film obtained from a composite consisting of tannic acid, bentonite and glycerol was evaluated. Nine gelatin films were manufactured by the casting method, using these materials, following a 2(3) factorial design with five replicates on the central point. The interactions among gelatin, tannic acid and bentonite caused a decrease in hydrogen bonds, while the polar groups of the gelatin chains were less exposed to interactions with water molecules. There was an increase in temperature and enthalpy of gelatin denaturation, due to increasing tannic acid and bentonite concentration. Tactoids were found in the gelatin films, caused mainly by bentonite polydispersion. A synergistic effect among tannic acid, bentonite and glycerol, which overall improved the measured gelatin film properties, was found. The best film formulation was that with 40, 150 and 250 g kg(-1) gelatin of tannic acid, bentonite and glycerol respectively, displaying a tensile strength of 38 MPa, an elongation at break of 136%, water vapor permeability of 1.28 × 10(-12) g (Pa s m)(-1) and solubility of 23.4%. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  1. Photoconductivity on nanocrystalline ZnO/TiO2 thin films obtained by sol-gel

    NASA Astrophysics Data System (ADS)

    Valverde-Aguilar, G.; García-Macedo, J. A.; Juárez-Arenas, R.

    2008-08-01

    In this paper we report results on the synthesis, characterization and photoconductivity behaviour of amorphous and nanocrystalline ZnO/TiO2 thin films. They were produced by the sol-gel process at room temperature by using the spin-coating method and deposited on glass substrates. The ZnO/TiO2 films were synthesized by using tetrabutyl orthotitanate and zinc nitrate hexahydrate as the inorganic precursors. The samples were sintered at 520°C for 1 hour. The obtained films were characterized by X-ray diffraction (XRD), optical absorption (OA), infrared spectroscopy (IR) and scanning electronic microscopy (SEM) studies. Photoconductivity studies were performed on amorphous and nanocrystalline (anatase phase) films to determine the charge transport parameters. The experimental data were fitted with straight lines at darkness and under illumination at 310 nm, 439 nm and 633 nm. This indicates an ohmic behavior. The Φμτ and Φl0 parameters were fitted by least-squares with straight lines (nanocrystalline films) and polynomial fits (amorphous films).

  2. The effect of substrate bias on the characteristics of CrN coatings deposited by DC-superimposed HiPIMS system

    NASA Astrophysics Data System (ADS)

    Zuo, X.; Xia, F.; Zhang, D.; Ke, P. L.; Wang, Q. M.; Wang, A. Y.

    2017-07-01

    Chromium nitride coatings were prepared by reactive DC-superimposed high-power-impulse magnetron sputtering (HiPIMS) system. The influence of substrate bias on the microstructure and mechanical properties of CrN coatings was investigated. XRD and cross-sectional SEM were utilized to characterize the film structures. Mechanical properties were characterized by nanoindentation and Vickers indentation test. The results revealed that the microstructure and mechanical properties of CrN coatings were affected by bias voltage. The CrN coatings exhibited dense and fine columnar grain structure with the hardness of about 18.7 GPa. The fracture toughness of CrN coatings was around 3.16 MPa ṡ m1/2. However, further increase of the bias voltage from -250 V to -300 V led to the degradation of coating properties.

  3. Composite materials obtained by the ion-plasma sputtering of metal compound coatings on polymer films

    NASA Astrophysics Data System (ADS)

    Khlebnikov, Nikolai; Polyakov, Evgenii; Borisov, Sergei; Barashev, Nikolai; Biramov, Emir; Maltceva, Anastasia; Vereshchagin, Artem; Khartov, Stas; Voronin, Anton

    2016-01-01

    In this article, the principle and examples composite materials obtained by deposition of metal compound coatings on polymer film substrates by the ion-plasma sputtering method are presented. A synergistic effect is to obtain the materials with structural properties of the polymer substrate and the surface properties of the metal deposited coatings. The technology of sputtering of TiN coatings of various thicknesses on polyethylene terephthalate films is discussed. The obtained composites are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and scanning tunneling microscopy (STM) is shown. The examples of application of this method, such as receiving nanocomposite track membranes and flexible transparent electrodes, are considered.

  4. Imino-chitosan biopolymeric films. Obtaining, self-assembling, surface and antimicrobial properties.

    PubMed

    Marin, Luminita; Ailincai, Daniela; Mares, Mihai; Paslaru, Elena; Cristea, Mariana; Nica, Valentin; Simionescu, Bogdan C

    2015-03-06

    The paper reports the preparation of twelve imino-chitosan biopolymer films by acid condensation of the amino groups of chitosan with various aldehydes, in aqueous medium, followed by slow water removal. FTIR spectroscopy has shown drastic conformation changes of chitosan macromolecular chains—from a stiff coil to a straight one, while wide angle X-ray diffraction evidenced a layered morphology of the biopolymer films. Contact angle and surface free energy determination indicated a higher biocompatibility of the new biopolymers as compared to the chitosan parent, while the microbiological screening demonstrated their self-defense properties against common and virulent pathogen agents. It was concluded that the reversibility of imine forming promotes the self-assembling of imino-chitosan biopolymer films into a lamellar morphology and, on the other hand, the slow release of the antimicrobial aldehyde in the microbiological culture. The obtained results demonstrate that chitosan polyamine is a challenging workbench to functional biodynamic materials.

  5. Nanoindentation on carbon thin films obtained from a C 60 ion beam

    NASA Astrophysics Data System (ADS)

    Dall'Asén, A. G.; Verdier, M.; Huck, H.; Halac, E. B.; Reinoso, M.

    2006-09-01

    Raman spectra, atomic force microscope (AFM) images, hardness ( H) and Young's modulus ( E) measurements were carried out in order to characterize carbon thin films obtained from a C 60 ion beam on silicon substrates at different deposition energies (from 100 up to 500 eV). The mechanical properties were studied via the nanoindentation technique. It has been observed by Raman spectroscopy and AFM that the microstructure presents significant changes for films deposited at energies close to 300 eV. However, these remarkable changes have not been noticeable on the mechanical properties: apparently H and E increase with higher deposition energy up to ˜11 and ˜116 GPa, respectively. These values are underestimated if the influence of the film roughness is not taken into account.

  6. Utilizing liquid crystal phases to obtain highly ordered thin films for organic electronics

    NASA Astrophysics Data System (ADS)

    Springer, Mike T.

    Organic electronic materials offer several advantages when compared to inorganic materials, but they suffer from low charge carrier mobility. Two major factors hindering effective charge transport in organic materials are: 1) effective wavefunction overlap in organic crystals and 2) the domain morphology of thin films. Charge transport in organic materials occurs via a hopping mechanism along the conjugated pi system. Often, rigid, aromatic organic materials crystallize in a herringbone, edge-to-face orientation, limiting pi-pi stacking and decreasing charge carrier mobility. Face-to-face orientation of aromatic rings decreases intermolecular pi-pi distances and increases wavefunction overlap. Control of the crystal structure can be achieved to some extent by tuning structural features of the molecule, like increasing the ratio of carbon atoms to hydrogen atoms in the aromatic rings; this is often achieved by introducing heteroatoms like sulfur and oxygen into the aromatic ring structure. Thin films of organic materials often contain many unaligned domains; this is caused by rapid crystallization. Control of the domain morphology of thin films has been shown to increase charge carrier mobility by 6 orders of magnitude for thin films of the same material. Liquid crystal phases allow a slow process of crystallization, whereby the molecules in a thin film can be slowly aligned into a monodomain before crystallization. The crystal-smectic phases, like smectic E, are particularly attractive for this strategy due to their high degree of intermolecular order. This project describes the synthesis and characterization of organic semiconductors designed to exhibit short pi-pi distances and highly ordered crystal-smectic phases to obtain thin films with high charge carrier mobility. The n,2-OBTTT series contains 15 newly designed and synthesized mesogens. The liquid crystal and solid crystal structures of these mesogens are examined and deposition conditions are optimized for

  7. MAPLE-based method to obtain biodegradable hybrid polymeric thin films with embedded antitumoral agents.

    PubMed

    Dinca, Valentina; Florian, Paula E; Sima, Livia E; Rusen, Laurentiu; Constantinescu, Catalin; Evans, Robert W; Dinescu, Maria; Roseanu, Anca

    2014-02-01

    In this work, antitumor compounds, lactoferrin [recombinant iron-free (Apo-rLf)], cisplatin (Cis) or their combination were embedded within a biodegradable polycaprolactone (PCL) polymer thin film, by a modified approach of a laser-based technique, matrix-assisted pulsed laser evaporation (MAPLE). The structural and morphological properties of the deposited hybrid films were analyzed by Fourier-transform infrared spectroscopy (FTIR) and atomic force microscopy (AFM). The in vitro effect on the cells' morphology and proliferation of murine melanoma B16-F10 cells was investigated and correlated with the films' surface chemistry and topography. Biological assays revealed decreased viability and proliferation, lower adherence, and morphological modifications in the case of melanoma cells cultured on both Apo-rLf and Cis thin films. The antitumor effect was enhanced by deposition of Apo-rLf with Cis within the same film. The unique capability of the new approach, based on MAPLE, to embed antitumor active factors within a biodegradable matrix for obtaining novel biodegradable hybrid platform with increased antitumor efficiency has been demonstrated.

  8. Polyhydroxyester films obtained by non-catalyzed melt-polycondensation of natural occurring fatty polyhydroxyacids.

    NASA Astrophysics Data System (ADS)

    Benitez, Jose; Heredia-Guerrero, José; Guzman-Puyol, Susana; Barthel, Markus; Dominguez, Eva; Heredia, Antonio

    2015-08-01

    Free-standing polyesters films from mono and polyhydroxylated fatty acids (C16 and C18) have been obtained by non-catalyzed melt-condensation polymerization in air at 150°C. Chemical characterization by Fourier Transform Infrared Spectroscopy (FTIR) and 13C Magic Angle Spinning Nuclear Magnetic Resonance (13C MAS-NMR) has confirmed the formation of the corresponding esters and the occurrence of hydroxyl partial oxidation which extent depends on the type of hydroxylation of the monomer (primary or secondary). Generally, polyester films obtained are hydrophobic, insoluble in common solvents, amorphous and infusible as revealed by X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC). In ?-polyhydroxy acids, esterification reaction with primary hydroxyls is preferential and, therefore, the structure can be defined as linear with variable branching depending on the amount of esterified secondary hydroxyls. The occurrence side oxidative reactions like the diol cleavage are responsible for chain cross-linking. Films are thermally stable up to 200-250°C though this limit can be extended up to 300°C in the absence of ester bonds involving secondary hydroxyls. By analogy with natural occurring fatty polyesters (i.e. cutin in higher plants) these polymers are proposed as biodegradable and non-toxic barrier films or coatings to be used, for instance, in food packing

  9. New electrochemical procedure for obtaining surface enhanced Raman scattering active polythiophene films on platinum

    NASA Astrophysics Data System (ADS)

    Bazzaoui, E. A.; Aeiyach, S.; Aubard, J.; Felidj, N.; Lévi, G.; Sakmeche, N.; Lacaze, P. C.

    1998-06-01

    A new electrochemical procedure for obtaining Surface Enhanced Raman Scattering (SERS) spectra of silver islands polybithiophene composite films is described. During the electropolymerization process which consists to use silver dodecylsulfate micellar aqueous solution mixed with bithiophene and LiClO4, silver cations are reduced, thus giving metallic silver particles embedded within the polybithiophene (PbT) film. Both doped and undoped PbT species display SERS spectra with exaltation factors varying between 40 and 200 with respect to the film prepared in sodium dodecylsulfate. Vibrational characterization of both doped and undoped species show that the amount of the polymer structural defects are more important in the oxidized species than in the reduced ones. This general method allows to synthesize various polymeric films displaying SERS effect and appears very promising for the structural study of these materials. Nous décrivons un procédé original pour synthétiser par voie électrochimique des films formés d'un composite de polybithiophène et d'îlots d'argent qui présentent des Spectres de Diffusion Raman Exaltée de Surface (DRES). Au cours de l'électropolymérisation d'une solution aqueuse micellaire de bithiophène en présence de dodécylsulfate d'argent (AgDS) et de LiClO4, les ions argent présents dans la solution se complexent avec le soufre du bithiophène et pénètrent dans le film polymère où ils sont réduits sous forme d'argent métallique. Les spectres Raman des deux formes réduite et oxydée du film ainsi obtenu présentent un effet DRES important avec un facteur d'exaltation variant entre 40 et 200 par rapport au même film électrosynthétisé en présence de dodécylsulfate de sodium (SDS). L'analyse vibrationnelle des deux formes redox montre que le taux de défauts est plus important dans la forme oxydée que dans la forme réduite. Cette méthode de polymérisation très générale, qui permet d'obtenir des polymères

  10. Characterization thin films TiO2 obtained in the magnetron sputtering process

    NASA Astrophysics Data System (ADS)

    Kamiński, Maciej; Firek, Piotr; Caban, Piotr

    2016-12-01

    The aim of the study was to elucidate influence parameters of magnetron sputtering process on growth rate and quality of titanium dioxide thin films. TiO2 films were produced on two inch silicon wafers by means of magnetron sputtering method. Characterization of samples was performed using ellipsometer and atomic force microscope (AFM). Currentvoltage (I-V) and capacitance-voltage (C-V) measurements were also carried out. The results enable to determine impact of pressure, power, gases flow and process duration on the physical parameters obtained layers such as electrical permittivity, flat band voltage and surface topography. Experiments were designed according to orthogonal array Taguchi method. Respective trends impact were plotted.

  11. Microstructures and properties of superconducting Y-Er-BaCu-O thin films obtained from disordered Y-Er-BaF2-Cu films

    NASA Technical Reports Server (NTRS)

    Cikmach, P.; Diociaiuti, M.; Fontana, A.; Giovannella, C.; Iannuzzi, M.; Lucchini, C.; Messi, R.; Paoluzi, L.; Scopa, L.; Tripodi, P.

    1990-01-01

    Since the first reports on superconducting thin films obtained by evaporating BaF2, Cu and Y(sup 1), or Yb or Er(sup 2), several others have followed. All these reports describe thin films prepared by means of molecular beam cells or electron guns. Researchers show that films with similar properties can be obtained by radio frequency sputtering of a single mosaic target composed by Y-Er, BaF2 and Cu. Process steps are described.

  12. Microstructures and properties of superconducting Y-Er-BaCu-O thin films obtained from disordered Y-Er-BaF2-Cu films

    NASA Technical Reports Server (NTRS)

    Cikmach, P.; Diociaiuti, M.; Fontana, A.; Giovannella, C.; Iannuzzi, M.; Lucchini, C.; Messi, R.; Paoluzi, L.; Scopa, L.; Tripodi, P.

    1990-01-01

    Since the first reports on superconducting thin films obtained by evaporating BaF2, Cu and Y(sup 1), or Yb or Er(sup 2), several others have followed. All these reports describe thin films prepared by means of molecular beam cells or electron guns. Researchers show that films with similar properties can be obtained by radio frequency sputtering of a single mosaic target composed by Y-Er, BaF2 and Cu. Process steps are described.

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

    SciTech Connect

    Shantheyanda, B. P.; Todi, V. O.; Sundaram, K. B.; Vijayakumar, A.; Oladeji, I.

    2011-09-15

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

  14. p-n Heterojunction of doped graphene films obtained by pyrolysis of biomass precursors.

    PubMed

    Latorre-Sánchez, Marcos; Primo, Ana; Atienzar, Pedro; Forneli, Amparo; García, Hermenegildo

    2015-02-25

    Nitrogen-doped graphene [(N)G] obtained by pyrolysis at 900 °C of nanometric chitosan films exhibits a Hall effect characteristic of n-type semiconductors. In contrast, boron-doped graphene [(B)G] obtained by pyrolysis of borate ester of alginate behaves as a p-type semiconductor based also on the Hall effect. A p-n heterojunction of (B)G-(N)G films is built by stepwise coating of a quartz plate using a mask. The heterojunction is created by the partial overlapping of the (B)G-(N)G films. Upon irradiation with a xenon lamp of aqueous solutions of H(2) PtCl(6) and MnCl(2) in contact with the heterojunction, preferential electron migration from (B)G to (N)G with preferential location of positive holes on (B)G is established by observation in scanning electron microscopy of the formation of Pt nanoparticles (NP) on (N)G and MnO(2) NP on (B)G. The benefits of the heterojunction with respect to the devices having one individual component as a consequence of the electron migration through the p-n heterojunction are illustrated by measuring the photocurrent in the (B)G-(N)G heterojunction (180% current enhancement with respect to the dark current) and compared it to the photocurrent of the individual (B)G (15% enhancement) and (N)G (55% enhancement) components. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Surface Modeling of Nanopatterned Polymer Films Obtained by Colloidal Templated Electropolymerization.

    PubMed

    Cernat, Andreea; Bodoki, Ede; Farcau, Cosmin; Aştilean, Simion; Griveau, Sophie; Bedioui, Fethi; Săndulescu, Robert

    2015-05-01

    Nanostructured polypyrrole surfaces are fabricated by a one step colloidal templating approach, involving simultaneous polystyrene bead deposition with the electropolymerization of the pyrrole monomer. Using response surface modeling, the influence of several experimental parameters was studied, following as response the resulted film's thickness and the nanopattern's surface density. Polystyrene beads of 100 nm were immobilized by the electropolymerization of pyrrole and the spheres were dissolved in tetrahydrofuran at room temperature. The obtained nanostructures were analyzed by atomic force microscopy (AFM) and the results served to build the mathematical model (central composite face centered design, quadratic model) best describing the correlations between variables and responses. The obtained response surface model revealed the specific influence of each of the studied variables over the followed responses and it also allowed the controlled fabrication of nanopatterned surfaces.

  16. All-3 d Electron-Hole Bilayers in CrN /MgO (111 ) Multilayers for Thermoelectric Applications

    NASA Astrophysics Data System (ADS)

    Botana, Antia S.; Pardo, Victor; Pickett, Warren E.

    2017-02-01

    CrN /MgO (111 ) multilayers modeled via ab initio calculations give rise to nanoscale, scalable, spatially separated two-dimensional electron and hole gases, each confined to its own CrN interface. Because of the Cr 3 d3 configuration, both electron and hole gases are based on correlated transition-metal layers involving bands of 3 d character. Transport calculations predict each subsystem will have a large thermopower, on the order of 250 μ V /K at room temperature. These heterostructures combine a large thermoelectric efficiency with scalable nanoscale conducting sheets; for example, operating at a temperature difference of 50 K, 40 bilayers could produce a 1-V voltage with a film thickness of 100 nm.

  17. Composition driven phase evolution and mechanical properties of Mo-Cr-N hard coatings

    NASA Astrophysics Data System (ADS)

    Klimashin, F. F.; Riedl, H.; Primetzhofer, D.; Paulitsch, J.; Mayrhofer, P. H.

    2015-07-01

    Although many research activities concentrate on transition metal nitrides, due to their excellent properties, only little is known about Mo-N based materials. We investigate in detail the influence of Cr on the structural evolution and mechanical properties of Mo-N coatings prepared at different nitrogen partial pressures. The chemical composition as well as the structural development of coatings prepared with N2-to-total pressure ratios ( pN2 /pT) of 0.32 and 0.44 can best be described by the quasi-binary Mo2N-CrN tie line. Mo2N and CrN are face centered cubic (fcc), only that for Mo2N half of the N-sublattice is vacant. Consequently, with increasing Cr content, also the N-sublattice becomes less vacant and the chemical composition of fcc single-phase ternaries can be described as Mo1-xCrxN0.5(1+x). These coatings exhibit an excellent agreement between experimentally and ab initio obtained lattice parameters of fcc Mo1-xCrxN0.5(1+x). When increasing the N2-to-total pressure ratio to pN2/pT = 0.69, the N-sublattice is already fully occupied for Cr-additions of x ≥ 0.4, as suggested by elastic recoil detection analysis and lattice parameter variations. The latter follows the ab initio obtained lattice parameters along the quasi-binary MoN-CrN tie line for x ≥ 0.5. The single-phase fcc coating with Cr/(Mo+Cr) of x ˜0.2, prepared with pN2 /pT = 0.32, exhibits the highest hardness of ˜34 GPa among all coatings studied.

  18. Antimicrobial films obtained from latex particles functionalized with quaternized block copolymers.

    PubMed

    Alvarez-Paino, Marta; Juan-Rodríguez, Rafael; Cuervo-Rodríguez, Rocío; Tejero, Rubén; López, Daniel; López-Fabal, Fátima; Gómez-Garcés, José L; Muñoz-Bonilla, Alexandra; Fernández-García, Marta

    2016-04-01

    New amphiphilic block copolymers with antimicrobial properties were obtained by atom transfer radical polymerization (ATRP) and copper catalyzed cycloaddition following two approaches, a simultaneous strategy or a two-step synthesis, which were proven to be very effective methods. These copolymers were subsequently quaternized using two alkyl chains, methyl and butyl, to amplify their antimicrobial properties and to investigate the effect of alkyl length. Antimicrobial experiments in solution were performed with three types of bacteria, two gram-positive and one gram-negative, and a fungus. Those copolymers quaternized with methyl iodide showed better selectivities on gram-positive bacteria, Staphylococcus aureus and Staphylococcus epidermidis, against red blood cells, demonstrating the importance of the quaternizing agent chosen. Once the solution studies were performed, we prepared poly(butyl methacrylate) latex particles functionalized with the antimicrobial copolymers by emulsion polymerization of butyl methacrylate using such copolymers as surfactants. The characterization by various techniques served to test their effectiveness as surfactants. Finally, films were prepared from these emulsions, and their antimicrobial activity was studied against the gram-positive bacteria. The results indicate that the antimicrobial efficiency of the films depends not only on the copolymer activity but also on other factors such as the surface segregation of the antimicrobial agent to the interface. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Effect of the lead oxide content on the microstructure and properties of PZT films obtained by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Mukhin, N. V.; Chigirev, D. A.

    2017-07-01

    Experimental studies of the influence of lead oxide as well as temperature and time of heat treatment on the microstructure and ferroelectric properties of PZT films obtained by the high-frequency magnetron sputtering method were carried out. It is shown that the change in the ferroelectric properties of polycrystalline PZT films can be explained by their heterophase structure with inclusions of lead oxide. It was found that the presence of a sublayer of lead oxide leads to a self-polarization of the film of the PZT. During the formation of the perovskite structure, the diffusion of lead oxide to the surface of the film occurs more intensively than after its formation.

  20. Nano-organized collagen layers obtained by adsorption on phase-separated polymer thin films.

    PubMed

    Zuyderhoff, Emilienne M; Dupont-Gillain, Christine C

    2012-01-31

    The organization of adsorbed type I collagen layers was examined on a series of polystyrene (PS)/poly(methyl methacrylate) (PMMA) heterogeneous surfaces obtained by phase separation in thin films. These thin films were prepared by spin coating from solutions in either dioxane or toluene of PS and PMMA in different proportions. Their morphology was unraveled combining the information coming from X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and water contact angle measurements. Substrates with PMMA inclusions in a PS matrix and, conversely, substrates with PS inclusions in a PMMA matrix were prepared, the inclusions being either under the form of pits or islands, with diameters in the submicrometer range. The organization of collagen layers obtained by adsorption on these surfaces was then investigated. On pure PMMA, the layer was quite smooth with assemblies of a few collagen molecules, while bigger assemblies were found on pure PS. On the heterogeneous surfaces, it appeared clearly that the diameter and length of collagen assemblies was modulated by the size and surface coverage of the PS domains. If the PS domains, either surrounding or surrounded by the PMMA phase, were above 600 nm wide, a heterogeneous distribution of collagen was found, in agreement with observations made on pure polymers. Otherwise, fibrils could be formed, that were longer compared to those observed on pure polymers. Additionally, the surface nitrogen content determined by XPS, which is linked to the protein adsorbed amount, increased roughly linearly with the PS surface fraction, whatever the size of PS domains, suggesting that adsorbed collagen amount on heterogeneous PS/PMMA surfaces is a combination of that observed on the pure polymers. This work thus shows that PS/PMMA surface heterogeneities can govern collagen organization. This opens the way to a better control of collagen supramolecular organization at interfaces, which could in turn allow cell

  1. Microstructures and properties of superconducting Y-ErBaCuO thin films obtained from disordered Y-ErBaF2Cu films

    NASA Technical Reports Server (NTRS)

    Cikmach, P.; Diociaiuti, M.; Fontana, A.; Giovannella, C.; Iannuzzi, M.; Lucchini, C.; Merlo, V.; Messi, R.; Paoluzi, L.; Scopa, L.

    1991-01-01

    The preparation procedure used to obtain superconducting thin films by radio frequency magnetron sputtering of a single mosaic target is described in detail. The single mosaic target is composed of (Y-Er), BaF2, and Cu.

  2. RBS Depth Profiling Analysis of (Ti, Al)N/MoN and CrN/MoN Multilayers

    NASA Astrophysics Data System (ADS)

    Han, Bin; Wang, Zesong; Devi, Neena; Kondamareddy, K. K.; Wang, Zhenguo; Li, Na; Zuo, Wenbin; Fu, Dejun; Liu, Chuansheng

    2017-03-01

    (Ti, Al)N/MoN and CrN/MoN multilayered films were synthesized on Si (100) surface by multi-cathodic arc ion plating system with various bilayer periods. The elemental composition and depth profiling of the films were investigated by Rutherford backscattering spectroscopy (RBS) using 2.42 and 1.52 MeV Li2+ ion beams and different incident angles (0°, 15°, 37°, and 53°). The microstructures of (Ti, Al)N/MoN multilayered films were evaluated by X-ray diffraction. The multilayer periods and thickness of the multilayered films were characterized by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) and then compared with RBS results.

  3. Biocompatible nanocrystalline octacalcium phosphate thin films obtained by pulsed laser deposition.

    PubMed

    Socol, G; Torricelli, P; Bracci, B; Iliescu, M; Miroiu, F; Bigi, A; Werckmann, J; Mihailescu, I N

    2004-06-01

    We extended for the first time pulsed laser ablation to the deposition of octacalcium phosphate Ca8H2(PO4)6.5H2O (OCP) thin films. The depositions were performed with a pulsed UV laser source (lambda=248 nm, tau> or =20 ns) in a flux of hot water vapors. The targets were sintered from crystalline OCP powder and the laser ablation fluence was set at values of 1.5-2 J/cm2. During depositions the collectors, Si or Ti substrates, were maintained at a constant temperature within the range 20-200 degrees C. The resulting structures were submitted to heat treatment in hot water vapors for up to 6 h. The best results were obtained at a substrate temperature of 150 degrees C during both deposition and post-deposition treatment. High-resolution electron microscopy and XRD at grazing incidence indicated that the coatings obtained were made of nanocrystalline OCP. Cross-section TEM investigations showed that the coatings contained droplets stacked on Ti substrates as well as distributed across the entire thickness of the arborescence-like structure layers. The results of WST-1 assay, cell adherence, DNA replication, and caspase-1 activity confirmed the good biocompatibility of the coatings.

  4. Characteristics of submicron pores obtained by chemical etching of nuclear tracks in polycarbonate films

    NASA Astrophysics Data System (ADS)

    Guillot, G.; Rondelez, F.

    1981-12-01

    Calibrated pores in the range 102-2×103 Å have been obtained by chemical etching of polycarbonate thin films irradiated with high energy krypton ions (500 MeV, Kr25+). Both the amorphous and the crystalline forms of polycarbonate (Makrofol, Bayer), further designated by their respective trade names N and KG, have been investigated up to thicknesses of 60 μm, close to the theoretical ion range of 77 μm. From conductivity studies, three different domains have been separated around the ion track: A highly damaged core of radius ?50 Å with a fast etching rate vT ≊104 Å/min, an intermediate zone of radius ?500 Å with an etching rate vI = 0.9 Å/min, an outer region with an etching rate equal to that of the undamaged material, vG = 0.47 Å/min. These observations are compatible with the delta ray model for track formation in plastic materials. Scanning electron microscope investigations have revealed that the pores formed in the N material are straight cylinders with a narrow distribution of the pore entrance diameters. On the other hand, the pores for the KG type are much less uniform and appear to be tapered, the difference between the two sides of the membrane being as much as 50%. These characteristics could be related to inhomogeneities in the morphological structure due to (i) the finite size of the crystalline domains and (ii) an asymetric manufacturer's processing of the film surfaces.

  5. Surface morphological evolution of epitaxial CrN(001) layers

    SciTech Connect

    Frederick, J.R.; Gall, D.

    2005-09-01

    CrN layers, 57 and 230 nm thick, were grown on MgO(001) at T{sub s}=600-800 deg. C by ultrahigh-vacuum magnetron sputter deposition in pure N{sub 2} discharges from an oblique deposition angle {alpha}=80 deg. . Layers grown at 600 deg. C nucleate as single crystals with a cube-on-cube epitaxial relationship with the substrate. However, rough surfaces with cauliflower-type morphologies cause the nucleation of misoriented CrN grains that develop into cone-shaped grains that protrude out of the epitaxial matrix to form triangular faceted surface mounds. The surface morphology of epitaxial CrN(001) grown at 700 deg. C is characterized by dendritic ridge patterns extending along the orthogonal <110> directions superposed by square-shaped super mounds with <100> edges. The ridge patterns are attributed to a Bales-Zangwill instability while the supermounds form due to atomic shadowing which leads to the formation of epitaxial inverted pyramids that are separated from the surrounding layer by tilted nanovoids. Growth at 800 deg. C yields complete single crystals with smooth surfaces. The root-mean-square surface roughness for 230-nm-thick layers decreases from 18.8 to 9.3 to 1.1 nm as T{sub s} is raised from 600 to 700 to 800 deg. C. This steep decrease is due to a transition in the roughening mechanism from atomic shadowing to kinetic roughening. Atomic shadowing is dominant at 600 and 700 deg. C, where misoriented grains and supermounds, respectively, capture a larger fraction of the oblique deposition flux in comparison to the surrounding epitaxial matrix, resulting in a high roughening rate that is described by a power law with an exponent {beta}>0.5. In contrast, kinetic roughening controls the surface morphology for T{sub s}=800 deg. C, as well as the epitaxial fraction of the layers grown at 600 and 700 deg. C, yielding relatively smooth surfaces and {beta}{<=}0.27.

  6. Photoluminescence and photoconductivity studies on amorphous and crystalline ZnO thin films obtained by sol-gel method

    NASA Astrophysics Data System (ADS)

    Valverde-Aguilar, G.; Manríquez Zepeda, J. L.

    2015-03-01

    Amorphous and crystalline ZnO thin films were obtained by the sol-gel process. A precursor solution of ZnO was synthesized by using zinc acetate dehydrate as inorganic precursor at room temperature. The films were spin-coated on silicon and glass wafers and gelled in humid air. The films were calcined at 450 °C for 15 min to produce ZnO nanocrystals with a wurtzite structure. Crystalline ZnO film exhibits an absorption band located at 359 nm (3.4 eV). Photoconductivity technique was used to determine the charge transport mechanism on both kinds of films. Experimental data were fitted with straight lines at darkness and under illumination at 355 and 633 nm wavelengths. This indicates an ohmic behavior. The photovoltaic and photoconductivity parameters were determined from the current density versus the applied electrical field results.

  7. Optical and structural properties of Zn /SUB x/ Cd /SUB 1-x/ S film obtained by solid-phase substitution

    SciTech Connect

    Kul'sha, A.M.; Lomako, V.M.; Mellikov, E.Y.; Tishkov, V.S.

    1986-01-01

    This paper reports the results of optical and electron microscope studies on Zn /SUB x/ Cd /SUB 1-x/ S alloy films. The films were prepared by replacing zinc atoms in zinc sulfide films with cadmium atoms obtained from the vapor phase of cadmium chloride. The results of the spectral transmission dependences for zinc sulfide films before and after annealing in cadmium chloride vapor are presented. From the electrondiffraction investigations of zinc sulfide annealed in the cadmium chloride vapor it is clear that recrystallization of the films occurs at higher temperatures and the crystal growth rate increases up to 450 degrees C. Layers of Zn /SUB x/ Cd /SUB 1-x/ S alloys, prepared in the fashion presented, are highly photosensitive in the blue light region.

  8. High-quality GaN films obtained by air-bridged lateral epitaxial growth

    NASA Astrophysics Data System (ADS)

    Ishibashi, Akihiko; Kidoguchi, Isao; Sugahara, Gaku; Ban, Yuzaburoh

    2000-12-01

    High-quality GaN films with low dislocation density and low wing tilt of c-axis orientation have been successfully obtained by a promising technique of selected area growth, namely air-bridged lateral epitaxial growth (ABLEG). A GaN film was grown from the exposed (0 0 0 1) top facet of the ridged GaN seed structures, whose side walls and etched bottoms were covered with silicon nitride mask, using low-pressure metalorganic vapor-phase epitaxy. The ridge-stripe structures of the GaN seed were constructed in the 1 1¯00 GaN direction. At the optimum growth temperature of 950°C, only the 1 1 2¯ 0 and {0 0 0 1} facets were obtained. Continuing the growth led to fabricating the air-bridged structure, where the coalescence of the wing region occurred. From the transmission electron microscopy study, it was found that most of the vertical dislocations along the c-axis were confined to the seed region, while the horizontal dislocations were newly generated in the vicinity of coalescence boundary. The densities of the vertical dislocations were about 9×10 8 cm -2 in the seed region, while below 1×10 6 cm -2 in other regions. The densities of the horizontal dislocations were about 1×10 6 cm -2 in the wing region and 4×10 7 cm -2 in the vicinity of the coalescence boundary, respectively. The X-ray diffraction (XRD) measurements revealed that the tilt angle of c-axis relative to underlying seed GaN was about 297 arcsec (0.083°), and the full-width at half-maximum of the XRD curve for the wing region was 138 arcsec, indicating that the wing region has high uniformity of c-axis orientation. Both of the wing and the coalescence boundary region exhibited atomically smooth surfaces with stepped terraces, whose root mean square roughness was found to be 0.089 nm by atomic force microscopy measurements.

  9. Relative phase and physical properties of CrN/AlN multilayer: A DFT study

    NASA Astrophysics Data System (ADS)

    Cudris, E. F.; Díaz F, J. H.; Espita R, M. J.

    2016-08-01

    Using first principles total-energy calculations within the framework of density functional theory, we studied the relative stability and the structural and electronic properties of multilayer CrN/AlN in the sodium chloride (NaCl), cesium chloride (CsCl), nickel arsenide (NiAs), zinc-blende, and wurtzite structures. The calculations were carried out using the method based on pseudopotentials, employed exactly as implemented in Quantum-ESPRESSO code. Based on total energy minimization, we found that the minimum global energy of CrN/AlN is obtained for the zincblende structure. Additionally, at high pressure our calculations show the possibility of a phase transition from the zincblende to NaCl structure. For the zincblende phase, the density of states analysis reveals that the multilayer exhibits a half-metallic behavior with a magnetic moment of 3.0^p/Cr-atom. These properties come essentially from the polarization of Cr-d and N-p states that cross the Fermi level. Due to these properties, the multilayer can potentially be used in the field of spintronics or spin injectors.

  10. Characterization of biodegradable films obtained from cysteine-mediated polymerized gliadins.

    PubMed

    Hernandez-Munoz, Pilar; Kanavouras, Antonis; Villalobos, Ricardo; Chiralt, Amparo

    2004-12-29

    This study focuses on the effect exerted by interchain disulfide bonds on the functional properties of films made from gliadins when cross-linked with cysteine. Gliadins were extracted from commercial wheat gluten with 70% aqueous ethanol, and cysteine was added to the film-forming solution to promote cross-linking between protein chains. The formation of interchain disulfide bonds was assessed by SDS-PAGE analysis. Gliadin films treated with cysteine maintain their integrity in water and become less extensible while their tensile strength increases as a consequence of the development of a more rigid network. The glass transition temperature of cross-linked films shifts to slightly higher values. The plasticizing effects of glycerol and moisture are also demonstrated. The mechanical behavior of cysteine-cross-linked gliadin films was compared to that of polymeric glutenins. Cross-linked gliadins displayed tensile strength values similar to those of glutenin films but achieved slightly lower elongation values. Cysteine-cross-linked gliadin films present the advantage that they are ethanol soluble, facilitating film fabrication or their application as a coating for food or for any other film or surface.

  11. Synthesis of novel precursors for PMN powders and the thin films obtained from them

    SciTech Connect

    Boyle, T.J.; Dimos, D.B.; Moore, G.J.

    1995-03-01

    Sol-gel processing has been widely used in the preparation of lead zirconate titanate (PZT) thin films. The authors have applied this methodology to the formation of lead magnesium niobate (PMN) spin-cast deposited thin films. Since there is a limited number of soluble, commercially available compounds, the authors have recently synthesized a series of novel metal alkoxides for use as precursors for generation of PMN thin films and powders. The process for generation of the perovskite phase of these PMN powders and films are reported.

  12. Study of nanocrystalline thin cobalt films with perpendicular magnetic anisotropy obtained by thermal evaporation

    NASA Astrophysics Data System (ADS)

    Kozłowski, Witold; Balcerski, Józef; Szmaja, Witold

    2017-02-01

    We have performed a detailed investigation of the morphological and magnetic domain structures of nanocrystalline thin cobalt films with perpendicular magnetic anisotropy. The films were thermally evaporated at an incidence angle of 0° in a vacuum of about 10-5 mbar and possessed thicknesses in the range from 60 nm to 100 nm. The films were studied by X-ray photoelectron spectroscopy (XPS), electron diffraction of transmission electron microscopy (TEM), atomic force microscopy (AFM), magnetic force microscopy (MFM) and the Fresnel mode of TEM. The films are polycrystalline and consist of very densely packed grains with sizes at the nanometer range. The grains are roundish in shape and generally exhibit no geometric alignment. The films are mainly composed of the hexagonal close-packed (HCP) phase of cobalt and possess preferential orientation of the cobalt grains with the hexagonal axis perpendicular to the film surface. 70 nm thick films and thicker have fully perpendicular magnetization, while 60 nm thick films possess clearly dominating perpendicular magnetization component. The magnetic domain structure is in the form of stripe domains forming a maze pattern. When the film thickness increases from 60 nm to 100 nm, the average grain size increases from 28.9 nm to 31.5 nm and the average domain width increases from 79.4 nm to 98.7 nm.

  13. Development of edible films obtained from submicron emulsions based on whey protein concentrate, oil/beeswax and brea gum.

    PubMed

    Cecchini, Juan Pablo; Spotti, María J; Piagentini, Andrea M; Milt, Viviana G; Carrara, Carlos R

    2017-06-01

    Edible films with whey protein concentrate (WPC) with a lipid component, sunflower oil (O) or beeswax (W), to enhance barrier to water vapor were obtained. Brea gum was used as emulsifier and also as matrix component. In order to achieve emulsion with small and homogeneous droplet size, an ultrasonicator equipment was used after obtaining a pre-emulsion using a blender. The films were made by casting. Effects of lipid fraction on droplet size, zeta potential, mechanical properties, water vapor permeability (WVP), solubility, and optical properties were determined. The droplet size of emulsions with BG decreased when decreasing the lipid content in the formulation. The zeta potential was negative for all the formulations, since the pH was close to 6 for all of them and pI of BG is close to 2.5, and pI of ß-lactoglobulin and α-lactalbumin (main proteins in WPC) are 5.2 and 4.1, respectively. Increasing W or SO content in blended films reduced the tensile strength and puncture resistance significantly. BG and WPC films without lipid presented better mechanical properties. The presence of lipids decreased the WVP, as expected, and those films having BG improved this property. BG films were slightly amber as a result of the natural color of the gum. BG has shown to be a good polysaccharide for emulsifying the lipid fraction and improving the homogeneity and mechanical properties of the films with WPC and beeswax or oil.

  14. Optimization of factors to obtain cassava starch films with improved mechanical properties

    NASA Astrophysics Data System (ADS)

    Monteiro, Mayra; Oliveira, Victor; Santos, Francisco; Barros Neto, Eduardo; Silva, Karyn; Silva, Rayane; Henrique, João; Chibério, Abimaelle

    2017-08-01

    In this study, was investigated the optimization of the factors that significantly influenced the mechanical property improvement of cassava starch films through complete factorial design 23. The factors to be analyzed were cassava starch, glycerol and modified clay contents. A regression model was proposed by the factorial analysis, aiming to estimate the condition of the individual factors investigated in the optimum state of the mechanical properties of the biofilm, using the following statistical tool: desirability function and response surface. The response variable that delimits the improvement of the mechanical property of the biofilm is the tensile strength, such improvement is obtained by maximizing the response variable. The factorial analysis showed that the best combination of factor configurations to reach the best response was found to be: with 5g of cassava starch, 10% of glycerol and 5% of modified clay, both percentages in relation to the dry mass of starch used. In addition, the starch biofilm showing the lowest response contained 2g of cassava starch, 0% of modified clay and 30% of glycerol, and was consequently considered the worst biofilm.

  15. CuInSe2 films and solar cells obtained by selenization of evaporated Cu-In layers

    NASA Astrophysics Data System (ADS)

    Basol, Bulent M.; Kapur, Vijay K.

    1989-05-01

    CuInSe2 films of various stoichiometries have been prepared by the two-stage process. In this method, Cu-In layers were first evaporated onto Mo-coated glass substrates in the form of stacks, and then they were selenized in a H2Se atmosphere at 400 °C to form the compound. CdZnS/CuInSe2 heterojunction solar cells were fabricated on these films and conversion efficiencies close to 7% were obtained.

  16. Optical properties of multilayer bimetallic films obtained by laser deposition of colloidal particles

    NASA Astrophysics Data System (ADS)

    Antipov, A.; Arakelian, S.; Vartanyan, T.; Gerke, M.; Istratov, A.; Kutrovskaya, S.; Kucherik, A.; Osipov, A.

    2016-11-01

    The optical properties of multilayer bimetallic films composed of silver and gold nanoparticles have been investigated. The dependence of the transmission spectra of the films on their morphology is demonstrated. A finite-difference time-domain (FDTD) simulation has confirmed that there is a dependence of the transmission spectra on the average distance between particles and the number of deposited layers.

  17. Physical properties of carbon films obtained by methane pyrolysis in an electric field

    NASA Astrophysics Data System (ADS)

    Brantov, S. K.; Tereshchenko, A. N.; Shteinman, E. A.; Yakimov, E. B.

    2016-03-01

    A method of synthesizing carbon films on single-crystal silicon substrates by methane pyrolysis in an electrical field is suggested. The pressure and temperature arising in a working chamber when the substrate is exposed to C-4 ions during pyrolysis are measured. Ion bombardment generates nuclei in the form of fibers about 2 μm in diameter providing the growth of a polycrystalline film. The resulting material is examined using electron microscopy and photo- and cathodoluminescence. Synthesized films are a composite material the matrix of which contains nanoclusters of a dissimilar crystalline nature. The effect of considerable two-stage decrease in the resistivity of the film material with increasing temperature from 300 to 1750 K is discovered. This points to the semiconducting properties of thick carbon films.

  18. Spectral transmittance of organic dye-doped glass films obtained by the solgel method

    NASA Astrophysics Data System (ADS)

    Nemoto, Shojiro; Hirokawa, Naoyuki

    1996-06-01

    The spectral transmittance of colored glass films synthesized by the solgel method is presented. The film was formed on a glass slide by dipping it into an organic dye-doped solution and, thereafter, by putting it into a furnace for solidification. Three dyes, Methylene Blue, Eosin, and Uranine, were used that exhibit transparent blue, pink, and yellow colors, respectively, when they are dissolved in the starting solution. We clarify how the spectral transmittance of the films varies with the solidification temperature. The films doped with two of the three dyes that exhibit violet, orange, and green colors are also synthesized, and their transmittance is measured. Moreover, the chemical durability of the films and the transmittance change caused by aging and illumination are examined. organic dye, solgel method.

  19. Microwave synthesis of calcium bismuth niobate thin films obtained by the polymeric precursor method

    SciTech Connect

    Simoes, A.Z.; Ramirez, M.A. . E-mail: miganr@kenter.com; Ries, A.; Wang, F.; Longo, E.; Varela, J.A.

    2006-08-10

    The crystal structure, surface morphology and electrical properties of layered perovskite calcium bismuth niobate thin films (CaBi{sub 2}Nb{sub 2}O{sub 9}-CBN) deposited on platinum coated silicon substrates by the polymeric precursor method have been investigated. The films were crystallized in a domestic microwave and in a conventional furnace. X-ray diffraction and atomic force microscopy analysis confirms that the crystallinity and morphology of the films are affected by the different annealing routes. Ferroelectric properties of the films were determined with remanent polarization P {sub r} and a drive voltage V {sub c} of 4.2 {mu}C/cm{sup 2} and 1.7 V for the film annealed in the conventional furnace and 1.0 {mu}C/cm{sup 2} and 4.0 V for the film annealed in microwave furnace, respectively. A slight decay after 10{sup 8} polarization cycles was observed for the films annealed in the microwave furnace indicating a reduction of the domain wall mobility after interaction of the microwave energy with the bottom electrode.

  20. Fluorinated graphene dielectric films obtained from functionalized graphene suspension: preparation and properties.

    PubMed

    Nebogatikova, N A; Antonova, I V; Prinz, V Ya; Kurkina, I I; Vdovin, V I; Aleksandrov, G N; Timofeev, V B; Smagulova, S A; Zakirov, E R; Kesler, V G

    2015-05-28

    In the present study, we have examined the interaction between a suspension of graphene in dimethylformamide and an aqueous solution of hydrofluoric acid, which was found to result in partial fluorination of suspension flakes. A considerable decrease in the thickness and lateral size of the graphene flakes (up to 1-5 monolayers in thickness and 100-300 nm in diameter) with increasing duration of fluorination treatment is found to be accompanied by a simultaneous transition of the flakes from the conducting to the insulating state. Smooth and uniform insulating films with a roughness of ∼2 nm and thicknesses down to 20 nm were deposited from the suspension on silicon. The electrical and structural properties of the films suggest their use as insulating elements in thin-film nano- and microelectronic device structures. In particular, it was found that the films prepared from the fluorinated suspension display rather high breakdown voltages (field strength of (1-3) × 10(6) V cm(-1)), ultralow densities of charges in the film and at the interface with the silicon substrate in metal-insulator-semiconductor structures (∼(1-5) × 10(10) cm(-2)). Such excellent characteristics of the dielectric film can be compared only to well-developed SiO2 layers. The films from the fluorinated suspension are cheap, practically feasible and easy to produce.

  1. Nanostructured MgTiO3 thick films obtained by electrophoretic deposition from nanopowders prepared by solar PVD

    NASA Astrophysics Data System (ADS)

    Apostol, Irina; Mahajan, Amit; Monty, Claude J. A.; Venkata Saravanan, K.

    2015-12-01

    A novel combination of solar physical vapor deposition (SPVD) and electrophoretic deposition (EPD) that was developed to grow MgTiO3 nanostructured thick films is presented. Obtaining nanostructured MgTiO3 thick films, which can replace bulk ceramic components, a major trend in electronic industry, is the main objective of this work. The advantage of SPVD is direct synthesis of nanopowders, while EPD is simple, fast and inexpensive technique for preparing thick films. SPVD technique was developed at CNRS-PROMES Laboratory, Odeillo-Font Romeu, France, while the EPD was performed at University of Aveiro - DeMAC/CICECO, Portugal. The nanopowders with an average crystallite size of about 30 nm prepared by SPVD were dispersed in 50 ml of acetone in basic media with addition of triethanolamine. The obtained well-dispersed and stable suspensions were used for carrying out EPD on 25 μm thick platinum foils. After deposition, films with thickness of about 22-25 μm were sintered in air for 15 min at 800, 900 and 1000 °C. The structural and microstructural characterization of the sintered thick films was carried out using XRD and SEM, respectively. The thickness of the sintered samples were about 18-20 μm, which was determined by cross-sectional SEM. Films sintered at 900 °C exhibit a dielectric constant, ɛr ∼18.3 and dielectric loss, tan δ ∼0.0012 at 1 MHz. The effects of processing techniques (SPVD and EPD) on the structure, microstructure and dielectric properties are reported in detail. The obtained results indicate that the thick films obtained in the present study can be promising for low loss materials for microwave and millimeter wave applications.

  2. Structural and magnetic properties of NiZn and Zn ferrite thin films obtained by laser ablation deposition

    SciTech Connect

    Sorescu, Monica; Diamandescu, L.; Swaminathan, R.; McHenry, M.E.; Feder, M.

    2005-05-15

    Laser ablation deposition has been used to synthesize nanoscale ferrite structures. Our investigations were performed on NiZn and Zn ferrite films deposited on silicon(100) substrates. Films produced by laser ablation at room temperature were annealed at 550 deg. C for 1 h. Other films were deposited directly at a 550 deg. C substrate temperature without subsequent annealing. Complementary x-ray diffraction and superconducting quantum interference device magnetometry measurements helped identify the optimum laser ablation deposition conditions for obtaining the desired nanoferrite structures. From the hysteresis loops at 300 and 10 K we identified the paramagnetic or ferromagnetic behavior of the films. The zero field cooled-field cooled (ZFC-FC) magnetization, M(T), curves yielded the value of the blocking temperature in both NiZn and Zn ferrite systems.

  3. Effect of replacement of corn starch by whey protein isolate in biodegradable film blends obtained by extrusion.

    PubMed

    Azevedo, Viviane Machado; Borges, Soraia Vilela; Marconcini, José Manoel; Yoshida, Maria Irene; Neto, Alfredo Rodrigues Sena; Pereira, Tamara Coelho; Pereira, Camila Ferreira Gonçalves

    2017-02-10

    The aim of this study was to evaluate the effect of replacing corn starch by whey protein isolated (WPI) in biodegradable polymer blends developed by extrusion. X-ray diffraction showed the presence of a Vh-type crystalline arrangement. The films were homogeneous, indicating strong interfacial adhesion between the protein and the thermoplastic starch matrix (TPS) as observed in scanning electron microscopy. The addition of WPI on TPS matrix promoted an increase in the thermal stability of the materials. It was observed 58.5% decrease in the water vapor permeability. The effect of corn starch substitution by WPI on mechanical properties resulted in a more resistant and less flexible film when compared the TPS film. The addition of WPI caused greenish yellow color and less transparent films. The substitution of corn starch by WPI made it possible to obtain polymer blends with improved properties and represents an innovation for application as a packaging material.

  4. Comparative studies on single-layer reduced graphene oxide films obtained by electrochemical reduction and hydrazine vapor reduction.

    PubMed

    Wang, Zhijuan; Wu, Shixin; Zhang, Juan; Chen, Peng; Yang, Guocheng; Zhou, Xiaozhu; Zhang, Qichun; Yan, Qingyu; Zhang, Hua

    2012-02-29

    The comparison between two kinds of single-layer reduced graphene oxide (rGO) sheets, obtained by reduction of graphene oxide (GO) with the electrochemical method and hydrazine vapor reduction, referred to as E-rGO and C-rGO, respectively, is systematically studied. Although there is no morphology difference between the E-rGO and C-rGO films adsorbed on solid substrates observed by AFM, the reduction process to obtain the E-rGO and C-rGO films is quite different. In the hydrazine vapor reduction, the nitrogen element is incorporated into the obtained C-rGO film, while no additional element is introduced to the E-rGO film during the electrochemical reduction. Moreover, Raman spectra show that the electrochemical method is more effective than the hydrazine vapor reduction method to reduce the GO films. In addition, E-rGO shows better electrocatalysis towards dopamine than does C-rGO. This study is helpful for researchers to understand these two different reduction methods and choose a suitable one to reduce GO based on their experimental requirements.

  5. Comparative studies on single-layer reduced graphene oxide films obtained by electrochemical reduction and hydrazine vapor reduction

    NASA Astrophysics Data System (ADS)

    Wang, Zhijuan; Wu, Shixin; Zhang, Juan; Chen, Peng; Yang, Guocheng; Zhou, Xiaozhu; Zhang, Qichun; Yan, Qingyu; Zhang, Hua

    2012-02-01

    The comparison between two kinds of single-layer reduced graphene oxide (rGO) sheets, obtained by reduction of graphene oxide (GO) with the electrochemical method and hydrazine vapor reduction, referred to as E-rGO and C-rGO, respectively, is systematically studied. Although there is no morphology difference between the E-rGO and C-rGO films adsorbed on solid substrates observed by AFM, the reduction process to obtain the E-rGO and C-rGO films is quite different. In the hydrazine vapor reduction, the nitrogen element is incorporated into the obtained C-rGO film, while no additional element is introduced to the E-rGO film during the electrochemical reduction. Moreover, Raman spectra show that the electrochemical method is more effective than the hydrazine vapor reduction method to reduce the GO films. In addition, E-rGO shows better electrocatalysis towards dopamine than does C-rGO. This study is helpful for researchers to understand these two different reduction methods and choose a suitable one to reduce GO based on their experimental requirements.

  6. Comparative studies on single-layer reduced graphene oxide films obtained by electrochemical reduction and hydrazine vapor reduction

    PubMed Central

    2012-01-01

    The comparison between two kinds of single-layer reduced graphene oxide (rGO) sheets, obtained by reduction of graphene oxide (GO) with the electrochemical method and hydrazine vapor reduction, referred to as E-rGO and C-rGO, respectively, is systematically studied. Although there is no morphology difference between the E-rGO and C-rGO films adsorbed on solid substrates observed by AFM, the reduction process to obtain the E-rGO and C-rGO films is quite different. In the hydrazine vapor reduction, the nitrogen element is incorporated into the obtained C-rGO film, while no additional element is introduced to the E-rGO film during the electrochemical reduction. Moreover, Raman spectra show that the electrochemical method is more effective than the hydrazine vapor reduction method to reduce the GO films. In addition, E-rGO shows better electrocatalysis towards dopamine than does C-rGO. This study is helpful for researchers to understand these two different reduction methods and choose a suitable one to reduce GO based on their experimental requirements. PMID:22373422

  7. Titanium oxide thin films obtained with physical and chemical vapour deposition methods for optical biosensing purposes.

    PubMed

    Dominik, M; Leśniewski, A; Janczuk, M; Niedziółka-Jönsson, J; Hołdyński, M; Wachnicki, Ł; Godlewski, M; Bock, W J; Śmietana, M

    2017-07-15

    This work discusses an application of titanium oxide (TiOx) thin films deposited using physical (reactive magnetron sputtering, RMS) and chemical (atomic layer deposition, ALD) vapour deposition methods as a functional coating for label-free optical biosensors. The films were applied as a coating for two types of sensors based on the localised surface plasmon resonance (LSPR) of gold nanoparticles deposited on a glass plate and on a long-period grating (LPG) induced in an optical fibre. Optical and structural properties of the TiOx thin films were investigated and discussed. It has been found that deposition method has a significant influence on optical properties and composition of the films, but negligible impact on TiOx surface silanization effectiveness. A higher content of oxygen with lower Ti content in the ALD films leads to the formation of layers with higher refractive index and slightly higher extinction coefficient than for the RMS TiOx. Moreover, application of the TiOx film independently on deposition method enables not only for tuning of the spectral response of the investigated biosensors, but also in case of LSPR for enhancing the ability for biofunctionalization, i.e., TiOx film mechanically protects the nanoparticles and induces change in the biofunctionalization procedure to the one typical for oxides. TiOx coated LSPR and LPG sensors with refractive index sensitivity of close to 30 and 3400nm/RIU, respectively, were investigated. The ability for molecular recognition was evaluated with the well-known complex formation between avidin and biotin as a model system. The shift in resonance wavelength reached 3 and 13.2nm in case of LSPR and LPG sensors, respectively. Any modification in TiOx properties resulting from the biofunctionalization process can be also clearly detected.

  8. Study on corrections of dose images obtained with Gafchromic EBT3 films for measurements in phantoms irradiated with proton beams

    SciTech Connect

    Gambarini, Grazia; Regazzoni, Veronica; Massari, Eleonora; Mirandola, Alfredo; Ciocca, Mario

    2015-07-01

    The response of Gafchromic EBT3 films depends on the LET of radiation. Some EBT3 films were exposed, in a solid-water phantom, to proton beams of various energies and the obtained depth-dose profiles were compared with the calculated profiles. As expected, a consistent reduction of the response in the Bragg peak region was observed. The ratio of measured and calculated values was evaluated, along dose profiles, for some energies of the incident proton beam. A method for correcting the dose images obtained with EBT3 films has been proposed and tested. The results confirm that the proposed method can be advantageous for achieving spatial distribution of the absorbed dose in proton therapy and deserves to be exhaustively developed. (authors)

  9. Measurement of the 208Pb(52Cr, n)259Sg Excitation Function

    SciTech Connect

    Folden III, C.M.; Dragojevic, I.; Dullmann, Ch.E.; Eichler, R.; Garcia, M.A.; Gates, J.M.; Nelson, S.L.; Sudowe, R.; Gregorich, K.E.; Hoffman, D.C.; Nitsche, H.

    2010-03-19

    The excitation function for the 208Pb(52Cr, n)259Sg reaction has been measured using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. The maximum cross section of pb is observed at a center-of-target laboratory-frame energy of 253.0 MeV. In total, 25 decay chains originating from 259Sg were observed and the measured decay properties are in good agreement with previous reports. In addition, a partial excitation function for the 208Pb(52Cr, 2n)258Sg reaction was obtained, and an improved 258Sg half-life of ms was calculated by combining all available experimental data.

  10. Some physical effects of reaction rate on PbS thin films obtained by chemical bath deposition

    NASA Astrophysics Data System (ADS)

    Altıokka, Barış; Baykul, Mevlana Celalettin; Altıokka, Mehmet Rıza

    2013-12-01

    Thin films of polycrystalline lead sulfide (PbS) have been deposited on glass substrates at 303±1 K using chemical bath deposition (CBD). The precipitation of PbS on solid surfaces under four different reaction conditions was performed using a sodium sulfite (Na2SO3) compound as an inhibitor. The kinetics model for the reaction between Pb2+ and S2- was developed according to the amounts of Pb2+ concentrations measured by atomic absorption spectroscopy (AAS) during the precipitation of PbS. The surface morphologies of PbS thin films were studied with a Scanning Electron Microscope (SEM). It was found that the precipitation rate effects the formation of pinhole. To obtain a good quality of thin films the optimum concentration of lead nitrate (Pb(NO3)2), sodium hydroxide (NaOH), thiourea (CS(NH2)2) and Na2SO3 in the final solution was determined to be 0.0089, 0.1460, 0.510 and 0.00023 M, respectively. The film structures were characterized by X-ray diffractometer (XRD). The XRD results showed that the films formed galena cubic structures which represent the natural mineral of PbS. The crystallite sizes of the films were found to be between 23 and 37 nm.

  11. Tight comparison of Mg and Y thin film photocathodes obtained by the pulsed laser deposition technique

    NASA Astrophysics Data System (ADS)

    Lorusso, A.; Gontad, F.; Solombrino, L.; Chiadroni, E.; Broitman, E.; Perrone, A.

    2016-11-01

    In this work Magnesium (Mg) and Yttrium (Y) thin films have been deposited on Copper (Cu) polycrystalline substrates by the pulsed laser ablation technique for photocathode application. Such metallic materials are studied for their interesting photoemission properties and are proposed as a good alternative to the Cu photocathode, which is generally used in radio-frequency guns. Mg and Y films were uniform with no substantial differences in morphology; a polycrystalline structure was found for both of them. Photoemission measurements of such cathodes based on thin films were performed, revealing a quantum efficiency higher than Cu bulk. Photoemission theory according to the three-step model of Spicer is invoked to explain the superior photoemission performance of Mg with respect to Y.

  12. Influence of CrN-coating thickness on the corrosion resistance behaviour of aluminium-based bipolar plates

    NASA Astrophysics Data System (ADS)

    Barranco, José; Barreras, Félix; Lozano, Antonio; Maza, Mario

    The electrical and corrosion properties of CrN-coated aluminium alloy Magnal-45 (Al-5083) probes have been evaluated, in order to assess their viability to be used as bipolar plates in polymer electrolyte fuel cells. To this end, ceramic micro-layers of chromium nitride (CrN) with different thicknesses (3, 4, and 5 μm) have been deposited on the surface of the Al alloy (Al-5083) using the physical vapour deposition (PVD) technique. A decrease in 2 orders of magnitude of I corr values for the coated Al has been observed compared to the as-received Al-alloy when the probes have been exposed to simulated anodic conditions in a micro-reactor. On the other hand, when subjected to a cathodic-simulated environment, the Al-CrN probes with 3 μm and 4 μm coatings have shown a decrease in I corr of one order of magnitude, while a variation of two orders of magnitude has also been obtained for the 5 μm coating.

  13. Water-repellent ZnO nanowires films obtained by octadecylsilane self-assembled monolayers

    NASA Astrophysics Data System (ADS)

    Badre, C.; Pauporté, T.; Turmine, M.; Dubot, P.; Lincot, D.

    2008-05-01

    Zinc oxide (ZnO) films with well-controlled morphologies have been prepared by electrochemical deposition. A seed layer of nanocrystallites of ZnO was prepared from which ZnO nanowires were grown from a low concentration of ZnCl 2. The nanowires are rough and dense and their superhydrophilicity is enhanced. A treatment with an alkylsilane (octadecylsilane) yields superhydrophobic surfaces with very high advancing and receding contact angles 173°/172° and a very low roll-off angle. Our superhydrophobic films are stable for more than 6 months.

  14. Process for obtaining multiple sheet resistances for thin film hybrid microcircuit resistors

    DOEpatents

    Norwood, David P.

    1989-01-01

    A standard thin film circuit containing Ta.sub.2 N (100 ohms/square) resirs is fabricated by depositing on a dielectric substrate successive layers of Ta.sub.2 N, Ti and Pd, with a gold layer to provide conductors. The addition of a few simple photoprocessing steps to the standeard TFN manufacturing process enables the formation of Ta.sub.2 N+Ti (10 ohms/square) and Ta.sub.2 N+Ti+Pd (1 ohm/square) resistors in the same otherwise standard thin film circuit structure.

  15. Indium-tin oxide films obtained by DC magnetron sputtering for improved Si heterojunction solar cell applications

    NASA Astrophysics Data System (ADS)

    Gu, Jin-Hua; Si, Jia-Le; Wang, Jiu-Xiu; Feng, Ya-Yang; Gao, Xiao-Yong; Lu, Jing-Xiao

    2015-11-01

    The indium-tin oxide (ITO) film as the antireflection layer and front electrodes is of key importance to obtaining high efficiency Si heterojunction (HJ) solar cells. To obtain high transmittance and low resistivity ITO films by direct-current (DC) magnetron sputtering, we studied the impacts of the ITO film deposition conditions, such as the oxygen flow rate, pressure, and sputter power, on the electrical and optical properties of the ITO films. ITO films of resistivity of 4×10-4 Ω·m and average transmittance of 89% in the wavelength range of 380-780 nm were obtained under the optimized conditions: oxygen flow rate of 0.1 sccm, pressure of 0.8 Pa, and sputtering power of 110 W. These ITO films were used to fabricate the single-side HJ solar cell without an intrinsic a-Si:H layer. However, the best HJ solar cell was fabricated with a lower sputtering power of 95 W, which had an efficiency of 11.47%, an open circuit voltage (Voc) of 0.626 V, a filling factor (FF) of 0.50, and a short circuit current density (Jsc) of 36.4 mA/cm2. The decrease in the performance of the solar cell fabricated with high sputtering power of 110 W is attributed to the ion bombardment to the emitter. The Voc was improved to 0.673 V when a 5 nm thick intrinsic a-Si:H layer was inserted between the (p) a-Si:H and (n) c-Si layer. The higher Voc of 0.673 V for the single-side HJ solar cell implies the excellent c-Si surface passivation by a-Si:H. Project supported by the National High Technology Research and Development Program of China (Grant No. 2011AA050501).

  16. Emission Dependent on composition of Si-rich-SiNX Films obtained by PECVD

    NASA Astrophysics Data System (ADS)

    Jaramillo Gomez, J. A.; Torchynska, T. V.; Casas Espinola, J. L.; Bentosa Gutiérrez, J. A.; Khomenkova, L.; Slaoui, A.

    2017-02-01

    Silicon-rich silicon nitride films with different stoichiometry were grown on silicon substrate using the plasma-enhanced chemical vapor deposition. The excess silicon content in the films was monitored via a variation of the NH3/SiH4 gas flow ratio from 0.45 up to 1.0. Morphology and luminescence properties of the films were studied by means of atomic force microscopy (AFM) and photoluminescence (PL) methods. High-temperature annealing was employed to produce the silicon nanocrystals in the films and to enhance the photoluminescence in the range of 1.6-3.0 eV. The PL spectrum was found to be complex due to the contribution of several radiative channels in emission process. It was determined that their competition leads to the non-monotonous variation of total PL peak position with the increase of the Si excess content. It was observed that the shape of PL spectra depends on an excitation wavelength. The ways to control the PL emission is proposed based on the discussion of the PL mechanism.

  17. Yttrium Iron Garnet Thin Films with Very Low Damping Obtained by Recrystallization of Amorphous Material.

    PubMed

    Hauser, Christoph; Richter, Tim; Homonnay, Nico; Eisenschmidt, Christian; Qaid, Mohammad; Deniz, Hakan; Hesse, Dietrich; Sawicki, Maciej; Ebbinghaus, Stefan G; Schmidt, Georg

    2016-02-10

    We have investigated recrystallization of amorphous Yttrium Iron Garnet (YIG) by annealing in oxygen atmosphere. Our findings show that well below the melting temperature the material transforms into a fully epitaxial layer with exceptional quality, both structural and magnetic. In ferromagnetic resonance (FMR) ultra low damping and extremely narrow linewidth can be observed. For a 56 nm thick layer a damping constant of α = (6.15 ± 1.50) · 10(-5) is found and the linewidth at 9.6 GHz is as small as 1.30 ± 0.05 Oe which are the lowest values for PLD grown thin films reported so far. Even for a 20 nm thick layer a damping constant of α = (7.35 ± 1.40) · 10(-5) is found which is the lowest value for ultrathin films published so far. The FMR linewidth in this case is 3.49 ± 0.10 Oe at 9.6 GHz. Our results not only present a method of depositing thin film YIG of unprecedented quality but also open up new options for the fabrication of thin film complex oxides or even other crystalline materials.

  18. Yttrium Iron Garnet Thin Films with Very Low Damping Obtained by Recrystallization of Amorphous Material

    PubMed Central

    Hauser, Christoph; Richter, Tim; Homonnay, Nico; Eisenschmidt, Christian; Qaid, Mohammad; Deniz, Hakan; Hesse, Dietrich; Sawicki, Maciej; Ebbinghaus, Stefan G.; Schmidt, Georg

    2016-01-01

    We have investigated recrystallization of amorphous Yttrium Iron Garnet (YIG) by annealing in oxygen atmosphere. Our findings show that well below the melting temperature the material transforms into a fully epitaxial layer with exceptional quality, both structural and magnetic. In ferromagnetic resonance (FMR) ultra low damping and extremely narrow linewidth can be observed. For a 56 nm thick layer a damping constant of α = (6.15 ± 1.50) · 10−5 is found and the linewidth at 9.6 GHz is as small as 1.30 ± 0.05 Oe which are the lowest values for PLD grown thin films reported so far. Even for a 20 nm thick layer a damping constant of α = (7.35 ± 1.40) · 10−5 is found which is the lowest value for ultrathin films published so far. The FMR linewidth in this case is 3.49 ± 0.10 Oe at 9.6 GHz. Our results not only present a method of depositing thin film YIG of unprecedented quality but also open up new options for the fabrication of thin film complex oxides or even other crystalline materials. PMID:26860816

  19. Yttrium Iron Garnet Thin Films with Very Low Damping Obtained by Recrystallization of Amorphous Material

    NASA Astrophysics Data System (ADS)

    Hauser, Christoph; Richter, Tim; Homonnay, Nico; Eisenschmidt, Christian; Qaid, Mohammad; Deniz, Hakan; Hesse, Dietrich; Sawicki, Maciej; Ebbinghaus, Stefan G.; Schmidt, Georg

    2016-02-01

    We have investigated recrystallization of amorphous Yttrium Iron Garnet (YIG) by annealing in oxygen atmosphere. Our findings show that well below the melting temperature the material transforms into a fully epitaxial layer with exceptional quality, both structural and magnetic. In ferromagnetic resonance (FMR) ultra low damping and extremely narrow linewidth can be observed. For a 56 nm thick layer a damping constant of α = (6.15 ± 1.50) · 10‑5 is found and the linewidth at 9.6 GHz is as small as 1.30 ± 0.05 Oe which are the lowest values for PLD grown thin films reported so far. Even for a 20 nm thick layer a damping constant of α = (7.35 ± 1.40) · 10‑5 is found which is the lowest value for ultrathin films published so far. The FMR linewidth in this case is 3.49 ± 0.10 Oe at 9.6 GHz. Our results not only present a method of depositing thin film YIG of unprecedented quality but also open up new options for the fabrication of thin film complex oxides or even other crystalline materials.

  20. Infrared Spectra and Structure of Poly(Vinylalcohol) Films Obtained From Aqueous Solutions with Potassium Iodide Additive

    NASA Astrophysics Data System (ADS)

    Sushko, N. I.; Zagorskaya, S. A.; Tretinnikov, O. N.

    2013-11-01

    The crystallinity and H-bonds in poly(vinylalcohol) films obtained from aqueous solutions with potassium iodide additive were investigated by IR spectroscopy. It was established that addition of KI caused the degree of polymer crystallinity to increase. The band of hydroxyl stretching vibrations (νOH) shifted toward higher frequency in spectra of films with KI additive. This indicated a change in the system of H-bonds in the polymer. The dependences of both the degree of crystallinity and the shift of the νOH band on the salt concentration were qualitatively different in shape.

  1. Modelling and experimental investigations of thin films of Mg phosphorus-doped tungsten bronzes obtained by ultrasonic spray pyrolysis.

    PubMed

    Jokanović, V; Nedić, Z; Colović, B

    2008-12-01

    In this study, the synthesis of thin films of Mg phosphorus doped tungsten bronzes (MgPTB; MgHPW(12)O(40).29H(2)O) by the self-assembly of nano-structured particles of MgPTB obtained using the ultrasonic spray pyrolysis method was investigated. As the precursor, MgPTB, prepared by the ionic exchange method, was used. Nano-structured particles of MgPTB were obtained using the ultrasonic spray pyrolysis method. The nano-structure of the particles used as the building blocks in the MgPTB thin film were investigated experimentally and theoretically, applying the model given in this article. The obtained data for the mean particle size and their size distribution show a high degree of agreement. These previously tailored particles used for the preparation of thin films during the next synthesis step, by their self-assembly over slow deposition on a silica glass substrate, show how it is possible to create thin MgPTB films under advance projected conditions of the applied physical fields with a fully determined nanostructure of their building block particles, with a relatively small roughness and unique physical properties.

  2. Size-dependent piezoelectricity of molybdenum disulfide (MoS2) films obtained by atomic layer deposition (ALD)

    NASA Astrophysics Data System (ADS)

    Huang, Yazhou; Liu, Lei; Sha, Jingjie; Chen, Yunfei

    2017-08-01

    As a member of transition metal dichalcogenides, MoS2 is an ideal low-dimensional piezoelectric material, which makes it attract wide attention for potential usage in next generation piezoelectric devices. In this study, the size-dependent piezoelectricity of MoS2 films with different grain sizes obtained at different temperatures by atomic layer deposition (ALD) was determined, which indicates that the grain size is critical to the piezoelectric constant. When the grain size is less than 120 nm, the piezoelectric constant increases with the increase in the grain size. Moreover, the piezoelectric constant first increases and then decreases with the increase in the film thickness. Therefore, piezoelectric constants of these MoS2 films can be modulated by changing the growth temperature and applying different ALD cycles.

  3. Nanocharacterization of TiN films obtained by Ion Vapor deposition

    NASA Astrophysics Data System (ADS)

    Lara, O. L.; Jerez, A. M.; Morantes, M. L.; Plata, A.; Torres, Y.; Lasprilla, M.; Zhabon, V.

    2011-01-01

    We evaluate and characterize the surface at the nanoscale level and take into account the temperature variation effect in the process of plasma ion deposition for H13 steel samples coated by Titanium Nitride (TiN). The interferometric microscopy and atomic force microscopy (AFM) were used to measure the film to analyze the variation of structural and morphological properties of nanofilms that depend on the temperature of sustrate.

  4. Cu doping concentration effect on the physical properties of CdS thin films obtained by the CBD technique

    NASA Astrophysics Data System (ADS)

    Albor Aguilera, M. L.; Flores Márquez, J. M.; Remolina Millan, A.; Matsumoto Kuwabara, Y.; González Trujillo, M. A.; Hernández Vásquez, C.; Aguilar Hernandez, J. R.; Hernández Pérez, M. A.; Courel-Piedrahita, M.; Madeira, H. T. Yee

    2017-08-01

    Cu(In, Ga)Se2 (CIGS) and Cu2ZnSnS4 (CZTS) semiconductors are direct band gap materials; when these types of material are used in solar cells, they provide efficiencies of 22.1% and 12.6%, respectively. Most traditional fabrication methods involve expensive vacuum processes including co-evaporation and sputtering techniques, where films and doping are conducted separately. On the other hand, the chemical bath deposition (CBD) technique allows an in situ process. Cu-doped CdS thin films working as a buffer layer on solar cells provide good performing devices and they may be deposited by low cost techniques such as chemical methods. In this work, Cu-doped CdS thin films were deposited using the CBD technique on SnO2:F (FTO) substrates. The elemental analysis and mapping reconstruction were conducted by EDXS. Morphological, optical and electrical properties were studied, and they revealed that Cu doping modified the CdS structure, band-gap value and the electrical properties. Cu-doped CdS films show high resistivity compared to the non-doped CdS. The appropriate parameters of Cu-doped CdS films were determined to obtain an adequate window or buffer layer on CIGS and CZTS photovoltaic solar cells.

  5. Influence of microstructure and surface topography on the electrical conductivity of Cu and Ag thin films obtained by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Polonyankin, D. A.; Blesman, A. I.; Postnikov, D. V.

    2017-05-01

    Conductive thin films formation by copper and silver magnetron sputtering is one of high technological areas for industrial production of solar energy converters, energy-saving coatings, flat panel displays and touch control panels because of their high electrical and optical properties. Surface roughness and porosity, average grain size, internal stresses, orientation and crystal lattice type, the crystallinity degree are the main physical properties of metal films affecting their electrical resistivity and conductivity. Depending on the film thickness, the dominant conduction mechanism can affect bulk conductivity due to the flow of electron gas, and grain boundary conductivity. The present investigation assesses the effect of microstructure and surface topography on the electrical conductivity of magnetron sputtered Cu and Ag thin films using X-ray diffraction analysis, scanning electron and laser interference microscopy. The highest specific conductivity (78.3 MS m-1 and 84.2 MS m-1, respectively, for copper and silver films at the thickness of 350 nm) were obtained with the minimum values of roughness and grain size as well as a high degree of lattice structuredness.

  6. Obtaining phase-pure CZTS thin films by annealing vacuum evaporated CuS/SnS/ZnS stack

    NASA Astrophysics Data System (ADS)

    Sánchez, T. G.; Mathew, X.; Mathews, N. R.

    2016-07-01

    Cu2ZnSnS4 (CZTS) thin films were obtained by the sequential thermal evaporation of metal binary sulfides in the order CuS/SnS/ZnS, followed by annealing in Ar/S atmosphere. The as-grown films were annealed at different temperatures ranging between 350 and 600 °C, for 10 min. Based on the preliminary results, the temperatures 550 °C and 600 °C were selected for further optimization and a second batch of films were annealed for different time durations (10 min, 30 min and 60 min) at these temperatures in order to identify the conditions to obtain phase-pure CZTS films. The structural properties and chemical compositions at each temperature were investigated in order to optimize the phase purity and film stoichiometry. We have identified adequate and reproducible conditions to obtain the elemental ratio Cu/(Zn+Sn) and Zn/Sn close to 0.78 and 1.19 respectively, which is in the range of material composition required for promising solar cells. In addition the optimized material showed excellent optical and electrical properties to be used as a photovoltaic absorber layer. The optical band gap was found to be about 1.52 eV, and the carrier concentration, hall mobility, and resistivity were in the range of 8.372×1015 cm-3, 3.103 cm2/Vs and 340.3 Ω-cm respectively. Three traps with activation energies 4.39, 8.1, and 34 meV were detected.

  7. Comparative study of structure and permeability of porous oxide films on aluminum obtained by single- and two-step anodization.

    PubMed

    Petukhov, Dmitrii I; Napolskii, Kirill S; Berekchiyan, Mikhail V; Lebedev, Alexander G; Eliseev, Andrey A

    2013-08-28

    A comparative study of the structure and transport properties of porous aluminum oxide films obtained by single- and two-step anodization was carried out. It is shown that the oxidation regime significantly affect the number of dead-ended channels, which results in more than twice the variation in membrane permeability. The effect is explained by multiple branching of channels on the initial stages of organization of the porous structure. Branching also occurs on later stages governing mass transport properties of porous anodic alumina films. A model describing transport properties of anodic aluminum oxide membranes based on pore branching on domain boundaries was suggested to fit experimental results of permeance of membranes obtained by both single- and two-step anodization.

  8. Oxidation behavior of AlN/CrN multilayered hard coatings

    NASA Astrophysics Data System (ADS)

    Tytko, Darius; Choi, Pyuck-Pa; Raabe, Dierk

    2017-06-01

    We report on the oxidation behavior of AlN/CrN multilayers at 900 °C, deposited by radio frequency magnetron sputtering. It is shown that oxidation in this system is controlled by diffusion of Cr towards the surface and formation of Cr2O3. Cr diffusion is found to mainly occur along grain boundaries. Thus, coherent cubic AlN/CrN multilayer regions with coarse columnar grain structures are found to be oxidation resistant, whereas regions decomposed into hexagonal AlN/cubic CrN are prone to oxidation.

  9. Study of PVD AlCrN Coating for Reducing Carbide Cutting Tool Deterioration in the Machining of Titanium Alloys

    PubMed Central

    Cadena, Natalia L.; Cue-Sampedro, Rodrigo; Siller, Héctor R.; Arizmendi-Morquecho, Ana M.; Rivera-Solorio, Carlos I.; Di-Nardo, Santiago

    2013-01-01

    The manufacture of medical and aerospace components made of titanium alloys and other difficult-to-cut materials requires the parallel development of high performance cutting tools coated with materials capable of enhanced tribological and resistance properties. In this matter, a thin nanocomposite film made out of AlCrN (aluminum–chromium–nitride) was studied in this research, showing experimental work in the deposition process and its characterization. A heat-treated monolayer coating, competitive with other coatings in the machining of titanium alloys, was analyzed. Different analysis and characterizations were performed on the manufactured coating by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDXS), and X-ray diffraction (XRD). Furthermore, the mechanical behavior of the coating was evaluated through hardness test and tribology with pin-on-disk to quantify friction coefficient and wear rate. Finally, machinability tests using coated tungsten carbide cutting tools were executed in order to determine its performance through wear resistance, which is a key issue of cutting tools in high-end cutting at elevated temperatures. It was demonstrated that the specimen (with lower friction coefficient than previous research) is more efficient in machinability tests in Ti6Al4V alloys. Furthermore, the heat-treated monolayer coating presented better performance in comparison with a conventional monolayer of AlCrN coating. PMID:28809266

  10. Study of PVD AlCrN Coating for Reducing Carbide Cutting Tool Deterioration in the Machining of Titanium Alloys.

    PubMed

    Cadena, Natalia L; Cue-Sampedro, Rodrigo; Siller, Héctor R; Arizmendi-Morquecho, Ana M; Rivera-Solorio, Carlos I; Di-Nardo, Santiago

    2013-05-24

    The manufacture of medical and aerospace components made of titanium alloys and other difficult-to-cut materials requires the parallel development of high performance cutting tools coated with materials capable of enhanced tribological and resistance properties. In this matter, a thin nanocomposite film made out of AlCrN (aluminum-chromium-nitride) was studied in this research, showing experimental work in the deposition process and its characterization. A heat-treated monolayer coating, competitive with other coatings in the machining of titanium alloys, was analyzed. Different analysis and characterizations were performed on the manufactured coating by scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDXS), and X-ray diffraction (XRD). Furthermore, the mechanical behavior of the coating was evaluated through hardness test and tribology with pin-on-disk to quantify friction coefficient and wear rate. Finally, machinability tests using coated tungsten carbide cutting tools were executed in order to determine its performance through wear resistance, which is a key issue of cutting tools in high-end cutting at elevated temperatures. It was demonstrated that the specimen (with lower friction coefficient than previous research) is more efficient in machinability tests in Ti6Al4V alloys. Furthermore, the heat-treated monolayer coating presented better performance in comparison with a conventional monolayer of AlCrN coating.

  11. Tunable spin-wave frequency gap in anisotropy-graded FePt films obtained by ion irradiation

    NASA Astrophysics Data System (ADS)

    Tacchi, S.; Pini, M. G.; Rettori, A.; Varvaro, G.; di Bona, A.; Valeri, S.; Albertini, F.; Lupo, P.; Casoli, F.

    2016-07-01

    The effect of graded anisotropy on static and dynamic magnetic properties of Ar+-irradiated FePt films has been investigated by static magnetometry, magnetic force microscopy, and Brillouin light scattering from thermally excited spin waves. A gradual variation of magnetic anisotropy with film thickness was obtained by Ar+ irradiation. The irradiation incidence angle influences the anisotropy profile: on decreasing α , a decreasing thickness of the hard L 10 phase and an increasing thickness of the soft A1 phase were obtained. Accordingly, the zero-field spin-wave frequency gap was found to decrease. In the sample with the highest soft-phase thickness the spin-wave frequency gap takes a substantial value (ν0≈6 GHz), which could be reproduced assuming the presence of a nonzero "rotatable" anisotropy (i.e., any direction in the film plane can be established as the easy axis by the application of a saturating magnetic field along this direction). The hypothesis is supported by both magnetometry and magnetic force microscopy data.

  12. Flexible heterostructures based on metal phthalocyanines thin films obtained by MAPLE

    NASA Astrophysics Data System (ADS)

    Socol, M.; Preda, N.; Rasoga, O.; Breazu, C.; Stavarache, I.; Stanculescu, F.; Socol, G.; Gherendi, F.; Grumezescu, V.; Popescu-Pelin, G.; Girtan, M.; Stefan, N.

    2016-06-01

    Heterostructures based on zinc phthalocyanine (ZnPc), magnesium phthalocyanine (MgPc) and 5,10,15,20-tetra(4-pyrydil)21H,23H-porphine (TPyP) were deposited on ITO flexible substrates by Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique. Organic heterostructures containing (TPyP/ZnPc(MgPc)) stacked or (ZnPc(MgPc):TPyP) mixed layers were characterized by X-ray diffraction-XRD, photoluminescence-PL, UV-vis and FTIR spectroscopy. No chemical decomposition of the initial materials was observed. The investigated structures present a large spectral absorption in the visible range making them suitable for organic photovoltaics applications (OPV). Scanning electron microscopy-SEM and atomic force microscopy-AFM revealed morphologies typical for the films prepared by MAPLE. The current-voltage characteristics of the investigated structures, measured in dark and under light, present an improvement in the current value (∼3 order of magnitude larger) for the structure based on the mixed layer (Al/MgPc:TPyP/ITO) in comparison with the stacked layer (Al/MgPc//TPyP/ITO). A photogeneration process was evidenced in the case of structures Al/ZnPc:TPyP/ITO with mixed layers.

  13. Nanoencapsulation of Rose-Hip Oil Prevents Oil Oxidation and Allows Obtainment of Gel and Film Topical Formulations.

    PubMed

    Contri, Renata V; Kulkamp-Guerreiro, Irene C; da Silva, Sheila Janine; Frank, Luiza A; Pohlmann, Adriana R; Guterres, Silvia S

    2016-08-01

    The rose-hip oil holds skin regenerating properties with applications in the dermatological and cosmetic area. Its nanoencapsulation might favor the oil stability and its incorporation into hydrophilic formulations, besides increasing the contact with the skin and prolonging its effect. The aim of the present investigation was to develop suitable rose-hip-oil-loaded nanocapsules, to verify the nanocapsule effect on the UV-induced oxidation of the oil and to obtain topical formulations by the incorporation of the nanocapsules into chitosan gel and film. The rose-hip oil (500 or 600 μL), polymer (Eudragit RS100®, 100 or 200 mg), and acetone (50 or 100 mL) contents were separately varied aiming to obtain an adequate size distribution. The results led to a combination of the factors acetone and oil. The developed formulation showed average diameter of 158 ± 6 nm with low polydispersity, pH of 5.8 ± 0.9, zeta potential of +9.8 ± 1.5 mV, rose-hip oil content of 54 ± 1 μL/mL and tendency to reversible creaming. No differences were observed in the nanocapsules properties after storage. The nanoencapsulation of rose-hip oil decreased the UVA and UVC oxidation of the oil. The chitosan gel and film containing rose-hip-oil-loaded nanocapsules showed suitable properties for cutaneous use. In conclusion, it was possible to successfully obtain rose-hip-oil-loaded nanocapsules and to confirm the nanocapsules effect in protecting the oil from the UV rays. The chitosan gel and film were considered interesting alternatives for incorporating the nanoencapsulated rose-hip oil, combining the advantages of the nanoparticles to the advantages of chitosan.

  14. Growth of single-crystal CrN on MgO(001): Effects of low-energy ion-irradiation on surface morphological evolution and physical properties

    NASA Astrophysics Data System (ADS)

    Gall, D.; Shin, C.-S.; Spila, T.; Odén, M.; Senna, M. J. H.; Greene, J. E.; Petrov, I.

    2002-03-01

    CrN layers, 0.5 μm thick, were grown on MgO(001) at Ts=570-775 °C by ultrahigh vacuum magnetically unbalanced magnetron sputter deposition in pure N2 discharges at 20 mTorr. Layers grown at Ts⩽700 °C are stoichiometric single crystals exhibiting cube-on-cube epitaxy: (001)CrN||(001)MgO with [100]CrN||[100]MgO. At higher temperatures, N2 desorption during deposition results in understoichiometric polycrystalline films with N fractions decreasing to 0.35, 0.28, and 0.07 with Ts=730, 760, and 775 °C, respectively. The surface morphologies of epitaxial CrN(001) layers were found to depend strongly on the incident ion-to-metal flux ratio JN2+/JCr which was varied between 1.7 and 14 with the ion energy maintained constant at 12 eV. The surfaces of layers grown with JN2+/JCr=1.7 consist of self-organized square-shaped mounds, due to kinetic roughening, with edges aligned along orthogonal <100> directions. The mounds have an average peak-to-valley height =5.1 nm and an in-plane correlation length of =0.21 μm. The combination of atomic shadowing by the mounds with low adatom mobility results in the formation of nanopipes extending along the growth direction. Increasing JN2+/JCr to 14 leads, due to increased adatom mobilities, to much smoother surfaces with =2.5 nm and =0.52 μm. Correspondingly, the nanopipe density decreases from 870 to 270 μm-2 to <20 μm-2 as JN2+/JCr is increased from 1.7 to 6 to 10. The hardness of dense CrN(001) is 28.5±1 GPa, but decreases to 22.5±1 GPa for layers containing significant nanopipe densities. The CrN(001) elastic modulus, 405±15 GPa, room-temperature resistivity, 7.7×10-2 Ω cm, and relaxed lattice constant, 0.4162±0.0008 nm, are independent of JN2+/JCr.

  15. Growth of Polarity-Controlled ZnO Films on (0001) Al2O3

    NASA Astrophysics Data System (ADS)

    Park, J. S.; Chang, J. H.; Minegishi, T.; Lee, H. J.; Park, S. H.; Im, I. H.; Hanada, T.; Hong, S. K.; Cho, M. W.; Yao, T.

    2008-05-01

    The polarity control of ZnO films grown on (0001) Al2O3 substrates by plasma-assisted molecular-beam epitaxy (P-MBE) was achieved by using a novel CrN buffer layer. Zn-polar ZnO films were obtained by using a Zn-terminated CrN buffer layer, while O-polar ZnO films were achieved by using a Cr2O3 layer formed by O-plasma exposure of a CrN layer. The mechanism of polarity control was proposed. Optical and structural quality of ZnO films was characterized by high-resolution X-ray diffraction and photoluminescence (PL) spectroscopy. Low-temperature PL spectra of Zn-polar and O-polar samples show dominant bound exciton (I8) and strong free exciton emissions. Finally, one-dimensional periodic structures consisting of Zn-polar and O-polar ZnO films were simultaneously grown on the same substrate. The periodic inversion of polarity was confirmed in terms of growth rate, surface morphology, and piezo response microscopy (PRM) measurement.

  16. Acid-Base Properties Of Glass Substrate And SiO2 - Bi2O3 Thin-Film Systems Obtained On It

    NASA Astrophysics Data System (ADS)

    Mal'chik, A. G.; Litovkin, S. V.; Filonov, A. V.; Ulyanova, O. V.; Gromov, V. E.

    2017-01-01

    The article describes an experimental research as a result of which SiO2 - Bi2O3 films have been synthesized of film-forming solutions based on tetraethoxysilane and bismuth nitrate (III). Acid-base properties of a glass substrate and SiO2 - Bi2O3 films obtained on it have been studied. The dependency of physical and chemical properties of SiO2 - Bi2O3 composites on their percentage composition have been revealed.

  17. Cell adhesion to cathodic arc plasma deposited CrAlSiN thin films

    NASA Astrophysics Data System (ADS)

    Kim, Sun Kyu; Pham, Vuong-Hung; Kim, Chong-Hyun

    2012-07-01

    Osteoblast cell response (cell adhesion, actin cytoskeleton and focal contact adhesion as well as cell proliferation) to CrN, CrAlSiN and Ti thin films was evaluated in vitro. Cell adhesion and actin stress fibers organization depended on the film composition significantly. Immunofluorescent staining of vinculin in osteoblast cells showed good focal contact adhesion on the CrAlSiN and Ti thin films but not on the CrN thin films. Cell proliferation was significantly greater on the CrAlSiN thin films as well as on Ti thin films than on the CrN thin films.

  18. Tribology and stability of organic monolayers on CrN: a comparison among silane, phosphonate, alkene, and alkyne chemistries.

    PubMed

    Pujari, Sidharam P; Li, Yan; Regeling, Remco; Zuilhof, Han

    2013-08-20

    The fabrication of chemically and mechanically stable monolayers on the surfaces of various inorganic hard materials is crucial to the development of biomedical/electronic devices. In this Article, monolayers based on the reactivity of silane, phosphonate, 1-alkene, and 1-alkyne moieties were obtained on the hydroxyl-terminated chromium nitride surface. Their chemical stability and tribology were systematically investigated. The chemical stability of the modified CrN surfaces was tested in aqueous media at 60 °C at pH 3, 7, and 11 and monitored by static water contact angle measurements, X-ray photoelectron spectroscopy (XPS), ellipsometry, and Fourier transform infrared reflection absorption spectroscopy (FT-IRRAS). The tribological properties of the resulting organic monolayers with different end groups (fluorinated or nonfluorinated) were studied using atomic force microscopy (AFM). It was found that the fluorinated monolayers exhibit a dramatic reduction of adhesion and friction force as well as excellent wear resistance compared to those of nonfluorinated coatings and bare CrN substrates. The combination of remarkable chemical stability and superior tribological properties makes these fluorinated monolayers promising candidates for the development of robust high-performance devices.

  19. Improved selenization procedure to obtain CuInSe{sub 2} thin films from sequentially electrodeposited precursors

    SciTech Connect

    Guillen, C.; Herrero, J.

    1996-02-01

    A new approach for CuInSe{sub 2} formation by sequential electrodeposition of Cu and In-Se layers and subsequent heat-treatment with elemental selenium in Ar and Ar + H{sub 2} flows is presented. The nature of the precursors and their evolution as a function of the selenization parameters have been studied by X-ray diffraction and X-ray photoelectron spectroscopy analysis. Sample temperature, Se-source temperature, and H{sub 2}/Ar volume ratio in the flow were the subject for optimization. A sample temperature above 400 C is needed to obtain single-phase CuInSe{sub 2} films. An increase in the film crystallinity has been reached by maintaining the Se-source temperature above 400 C. The introduction of H{sub 2} in the selenizing atmosphere has proven to be unsuitable, H{sub 2}Se formation must be avoided because it is more poisonous and less reactive than the elemental selenium vapor.

  20. Properties of Sb{sub 2}S{sub 3} and Sb{sub 2}Se{sub 3} thin films obtained by pulsed laser ablation

    SciTech Connect

    Virt, I. S.; Rudyj, I. O.; Kurilo, I. V.; Lopatynskyi, I. Ye.; Linnik, L. F.; Tetyorkin, V. V.; Potera, P.; Luka, G.

    2013-07-15

    The properties of Sb{sub 2}S{sub 3} and Sb{sub 2}Se{sub 3} thin films of variable thickness deposited onto Al{sub 2}O{sub 3}, Si, and KCl substrates are investigated by the method of pulsed laser ablation. The samples are obtained at a substrate temperature of 180 Degree-Sign C in a vacuum chamber with a residual pressure of 10{sup -5} Torr. The thickness of the films amounted to 40-1500 nm. The structure of the bulk material of the targets and films is investigated by the methods of X-ray diffraction and transmission high-energy electron diffraction, respectively. The electrical properties of the films are investigated in the temperature range of 253-310 K. It is shown that the films have semiconductor properties. The structural features of the films determine their optical parameters.

  1. CuO/ZnO coupled oxide films obtained by the electrodeposition technique and their photocatalytic activity in phenol degradation under solar irradiation.

    PubMed

    Paz, Diego S; Foletto, Edson L; Bertuol, Daniel A; Jahn, Sérgio L; Collazzo, Gabriela C; da Silva, Syllos S; Chiavone-Filho, Osvaldo; do Nascimento, Claudio A O

    2013-01-01

    CuO/ZnO coupled oxide films were electrodeposited onto an aluminum substrate and tested as photocatalysts in degradation of phenol molecules in aqueous solution under sunlight. The obtained films were characterized by X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The results showed that the photocatalytic activity of films was significant, especially to coupled oxide film with a CuO/ZnO ratio equal to 0.697, which presented about 70% degradation of the aromatic molecules and 42% of total organic carbon (TOC) removal at 300 min under solar irradiation. Therefore, this work highlights the potential application of CuO/ZnO coupled oxide films obtained by electrodeposition onto aluminum substrate in the field of photocatalysis.

  2. Physicochemical and Microstructural Characterization of Corn Starch Edible Films Obtained by a Combination of Extrusion Technology and Casting Technique.

    PubMed

    Fitch-Vargas, Perla Rosa; Aguilar-Palazuelos, Ernesto; de Jesús Zazueta-Morales, José; Vega-García, Misael Odín; Valdez-Morales, Jesús Enrique; Martínez-Bustos, Fernando; Jacobo-Valenzuela, Noelia

    2016-09-01

    Starch edible films (EFs) have been widely studied due to their potential in food preservation; however, their application is limited because of their poor mechanical and barrier properties. Because of that, the aim of this work was to use the extrusion technology (Ex T) as a pretreatment of casting technique to change the starch structure in order to obtain EFs with improved physicochemical properties. To this, corn starch and a mixture of plasticizers (sorbitol and glycerol, in different ratios) were processed in a twin screw extruder to generate the starch modification and subsequently casting technique was used for EFs formation. The best conditions of the Ex T and plasticizers concentration were obtained using response surface methodology. All the response variables evaluated, were affected significatively by the Plasticizers Ratio (Sorbitol:Glycerol) (PR (S:G)) and Extrusion Temperature (ET), while the Screw Speed (SS) did not show significant effect on any of these variables. The optimization study showed that the appropriate conditions to obtain EFs with the best mechanical and barrier properties were ET = 89 °C, SS = 66 rpm and PR (S:G) = 79.7:20.3. Once the best conditions were obtained, the optimal treatment was characterized according to its microstructural properties (X-ray diffraction, Scanning Electron Microscopy and Atomic Force Microscopy) to determine the damage caused in the starch during Ex T and casting technique. In conclusion, with the combination of Ex T and casting technique were obtained EFs with greater breaking strength and deformation, as well as lower water vapor permeability than those reported in the literature. © 2016 Institute of Food Technologists®

  3. High-temperature oxidation of CrN/AlN multilayer coatings

    NASA Astrophysics Data System (ADS)

    Bardi, U.; Chenakin, S. P.; Ghezzi, F.; Giolli, C.; Goruppa, A.; Lavacchi, A.; Miorin, E.; Pagura, C.; Tolstogouzov, A.

    2005-12-01

    Experiments are reported on sputter depth profiling of CrN/AlN multilayer abrasive coatings by secondary ion mass spectrometry (SIMS) coupled with sample current measurements (SCM). The coatings were deposited by a closed-field unbalanced magnetron sputtering. It is shown that after oxidation tests, performed in air at 900 °C for 2 h and at 1100 °C for 4 h, the layered structure begins to degrade but is not destroyed completely. Oxidation at 1100 °C for 20 h causes total destruction of the coatings that can be attributed to a fast diffusion of oxygen, nickel, manganese and other elements along defect paths (grain boundaries, dislocations, etc.) in the coating. There are practically no nitrides in the near-surface layer after such a treatment and all the metallic components are in the oxidized form as follows from the data obtained by X-ray photoelectron spectroscopy (XPS). According to XPS and mass-resolved ion scattering spectrometry (MARISS), the surface content of Al in the heat-treated coatings has decreased in comparison with the as-received sample and that of Cr increased. Both XPS and MARISS data exhibit real increase in superficial concentration of the substrate materials (Mn and Ni) that is controversial if using SIMS alone. SCM turned out to be an informative depth profiling method complementary to more expensive and complicated SIMS, being particularly useful for structures with different secondary electron emission properties of the layers. SCM with predetermined SIMS calibration allows a routine characterization of coatings and other multilayer structures, particularly, in situations where the expenses of analysis can be justified.

  4. Synthesis, Hardness, and Electronic Properties of Stoichiometric VN and CrN

    SciTech Connect

    Wang, Shanmin; Yu, Xiaohui; Zhang, Jianzhong; Wang, Liping; Leinenweber, Kurt; He, Duanwei; Zhao, Yusheng

    2015-11-09

    Here, we report synthesis of single-crystal VN and CrN through high-pressure ionexchange reaction routes. The final products are stoichiometric and have crystallite sizes in the range of 50-120 mu m. We also prepared VN and TiN crystals using high-pressure sintering of nitride powders. On the basis of single-crystal indentation testing, the determined asymptotic Vickers hardness for TiN, VN, and CrN is 18 (1), 10 (1), and 16 (1) GPa, respectively. Moreover, the relatively low hardness in VN indicates that the metallic bonding prevails due to the overfilled metallic a bonds, although the cation-anion covalent hybridization in this compound is much stronger than that in TiN and CrN. All three nitrides are intrinsically excellent metals at ambient pressure. In particular, VN exhibits superconducting transition at T-c approximate to 7.8 K, which is slightly lower than the reported values for nitrogen-deficient or crystallinedisordered samples due to unsuppressed "spin fluctuation" in the well-crystallized stoichiometric VN. The magnetostructural transition in CrN correlates with a metal metal transition at T-N = 240(5) K and is accompanied by a similar to 40% drop in electrical resistivity. Additionally, more detailed electronic properties are presented with new insights into these nitrides.

  5. Synthesis, Hardness, and Electronic Properties of Stoichiometric VN and CrN

    DOE PAGES

    Wang, Shanmin; Yu, Xiaohui; Zhang, Jianzhong; ...

    2015-11-09

    Here, we report synthesis of single-crystal VN and CrN through high-pressure ionexchange reaction routes. The final products are stoichiometric and have crystallite sizes in the range of 50-120 mu m. We also prepared VN and TiN crystals using high-pressure sintering of nitride powders. On the basis of single-crystal indentation testing, the determined asymptotic Vickers hardness for TiN, VN, and CrN is 18 (1), 10 (1), and 16 (1) GPa, respectively. Moreover, the relatively low hardness in VN indicates that the metallic bonding prevails due to the overfilled metallic a bonds, although the cation-anion covalent hybridization in this compound is muchmore » stronger than that in TiN and CrN. All three nitrides are intrinsically excellent metals at ambient pressure. In particular, VN exhibits superconducting transition at T-c approximate to 7.8 K, which is slightly lower than the reported values for nitrogen-deficient or crystallinedisordered samples due to unsuppressed "spin fluctuation" in the well-crystallized stoichiometric VN. The magnetostructural transition in CrN correlates with a metal metal transition at T-N = 240(5) K and is accompanied by a similar to 40% drop in electrical resistivity. Additionally, more detailed electronic properties are presented with new insights into these nitrides.« less

  6. Microstructure and Corrosion Behavior of CrN and CrSiCN Coatings

    NASA Astrophysics Data System (ADS)

    Cai, Feng; Yang, Qi; Huang, Xiao; Wei, Ronghua

    2010-07-01

    Three CrN-based coatings were deposited on 17-4PH stainless steel substrate using plasma enhanced magnetron sputtering (PEMS) technique. The microstructure and corrosion resistance were evaluated to examine the effect of Si and C in the coatings. The three coating compositions were CrN(Cr0.69N0.31), CrSiCN-1 (Cr0.55Si0.014C0.14N0.3), and CrSiCN-2 (Cr0.43Si0.037C0.24N0.3). The testing results indicated that with the increase of Si concentration, the coating microstructure transformed from B1 structure to B1 + Si3N4 structure. All the three coating systems were subjected to electrochemical tests in 3.5% NaCl solution at room temperature. Potentiodynamic polarization results revealed that the CrSiCN-2 coating had a higher anodic current density and a lower corrosion potential when compared to the CrN and CrSiCN-1 coatings. Extended exposure in 3.5% NaCl caused several localized corrosion to the CrSiCN-2 coating due to the porous coating structure. Electrochemical impedance spectroscopic measurements demonstrated that the CrSiCN-1 has better corrosion resistance than CrN and CrSiCN-2.

  7. Diagnostic quality of mammograms obtained with a new low-radiation-dose dual-screen and dual-emulsion film combination

    SciTech Connect

    Wojtasek, D.A.; Teixidor, H.S.; Govoni, A.F.; Gareen, I.F. )

    1990-02-01

    We evaluated the image quality of mammograms made by using a new dual-screen, dual-emulsion film combination (Kodak Min-R Fast screen, T-Mat Mll film) that permits reduction of radiation exposure by approximately 50% when compared with a standard single-screen, single-emulsion film system (Kodak Min-R screen, OM-1 film). This new film has been improved when compared with earlier T-Mat M film, including the introduction of an inert dye to reduce light crossover to essentially 0%. Mammogram pairs made with the dual-emulsion film combination and the standard single-emulsion film combination were obtained in 50 patients otherwise undergoing routine mammography. The image pairs were randomized and evaluated by three radiologists who used a three-point scale (better, same, or worse). Each pair was evaluated with regard to parenchymal contrast, sharpness, and latitude, as well as the number and sharpness of calcifications (n = 19) and sharpness of masses (n = 12) when present. All three observers found the dual-emulsion film combination to be better than or the same as the standard with regard to parenchymal sharpness (94-100%), the number and sharpness of calcifications (98-100%), and sharpness of masses (100%). Two observers found the dual-emulsion film combination to be significantly worse (p less than .05) than the standard with respect to parenchymal contrast (72%, 86%), and all three observers rated it significantly worse for film latitude (14 to 42%). Our results suggest that this new dual-emulsion film combination that allows mammography to be performed with less radiation exposure can be used without loss of image quality.

  8. Measurement of the {sup 208}Pb({sup 52}Cr,n){sup 259}Sg excitation function

    SciTech Connect

    Folden III, C. M.; Dragojevic, I.; Garcia, M. A.; Gates, J. M.; Nelson, S. L.; Hoffman, D. C.; Nitsche, H.; Duellmann, Ch. E.; Sudowe, R.; Gregorich, K. E.; Eichler, R.

    2009-02-15

    The excitation function for the {sup 208}Pb({sup 52}Cr,n){sup 259}Sg reaction has been measured using the Berkeley Gas-filled Separator at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron. The maximum cross section of 320{sub -100}{sup +110} pb is observed at a center-of-target laboratory-frame energy of 253.0 MeV. In total, 25 decay chains originating from {sup 259}Sg were observed and the measured decay properties are in good agreement with previous reports. In addition, a partial excitation function for the {sup 208}Pb({sup 52}Cr,2n){sup 258}Sg reaction was obtained, and an improved {sup 258}Sg half-life of 2.6{sub -0.4}{sup +0.6} ms was calculated by combining all available experimental data.

  9. Influence of the microstructure on the resulting 18R martensitic transformation of polycrystalline Cu−Al−Zn thin films obtained by sputtering and reactive annealing

    SciTech Connect

    Domenichini, P.; Condó, A.M.; Soldera, F.; Sirena, M.; Haberkorn, N.

    2016-04-15

    We report the influence of the microstructure on the martensitic transformation in polycrystalline Cu−Zn−Al thin films with 18R structure. The films are grown in two steps. First, Cu−Al thin films are obtained by DC sputtering. Second, the Zn is introduced in the Cu−Al thin films by the annealing them together with a bulk Cu−Zn−Al reference. The crystalline structure of the films was analyzed by X-ray diffraction and transmission electron microscopy. The martensitic transformation temperature was measured by electrical transport using conventional four probe geometry. It was observed that temperatures above 973 K are necessary for zincification of the samples to occur. The resulting martensitic transformation and its hysteresis (barrier for the transformation) depend on the grain size, topology and films thickness. - Highlights: • Polycrystalline Cu−Al−Zn thin films with nanometric grain size are sintered. • Influence of thermal annealing process on the microstructure is analyzed. • Martensitic transformation of Cu−Al−Zn thin films is strongly affected by the microstructure.

  10. The properties of ZnO films obtained by high-frequency magnetron deposition with subsequent vacuum annealing and plasma treatment

    NASA Astrophysics Data System (ADS)

    Redka, D. N.; Elanskaia, K. G.; Bakhchova, L. D.

    2017-07-01

    The method of high-frequency magnetron sputtering allows to obtain thin films of zinc oxide with nanostructured surface morphology and, consequently, with unique optical characteristics. Such coating can provide an increase in the number of particles penetrating the photovoltaic structure and the length of their optical path. Vacuum-plasma processing of ZnO films allows to change the morphology of their surface, and annealing largely influences the optical transmission.

  11. CuInS 2 thin films obtained through the annealing of chemically deposited In 2S 3-CuS thin films

    NASA Astrophysics Data System (ADS)

    Peña, Y.; Lugo, S.; Calixto-Rodriguez, M.; Vázquez, A.; Gómez, I.; Elizondo, P.

    2011-01-01

    In this work, we report the formation of CuInS 2 thin films on glass substrates by heating chemically deposited multilayers of copper sulfide (CuS) and indium sulfide (In 2S 3) at 300 and 350 °C in nitrogen atmosphere at 10 Torr. CIS thin films were prepared by varying the CuS layer thickness in the multilayers with indium sulfide. The XRD analysis showed that the crystallographic structure of the CuInS 2 (JCPDS 27-0159) is present on the deposited films. From the optical analysis it was estimated the band gap value for the CIS film (1.49 eV). The electrical conductivity varies from 3 × 10 -8 to 3 Ω -1 cm -1 depending on the thickness of the CuS film. CIS films showed p-type conductivity.

  12. Hardness and nitrogen bonding structure of AlxTi1-xN/CrN multilayer hard coating.

    PubMed

    Seo, Jong-Hyun; Yoon, Sang-Won; Chae, Keun-Hwa; Park, Jong-Keuk; Song, Jong-Han; Jayaram, Vickram; Lee, Kon-Bae; Seong, Tae-Yeon; Kwon, Hoon; Ahn, Jae-Pyoung

    2012-02-01

    AlxTi1-xN/CrN multilayer coatings were fabricated by magnetron sputtering and those hardness variations were studied by observing the crack propagation and measuring the chemical bonding state of nitrides by Ti addition. While AlN/CrN multilayer shown stair-like crack propagation, AlxTi1-xN/CrN multilayer illustrated straight crack propagation. Most interestingly, Ti addition induced more broken nitrogen bonds in the nitride multilayers, leading to the reduction of hardness. However, the hardness of Al0.25Ti0.75N/CrN multilayer, having high Ti contents, increased by the formation of many Ti-N bond again instead of Al-N bond. From these results, we found that linear crack propagation behavior was dominated by broken nitrogen bonds in the AlxTi1-xN/CrN multilayer coatings.

  13. Healing activity evaluation of the galactomannan film obtained from Cassia grandis seeds with immobilized Cratylia mollis seed lectin.

    PubMed

    Albuquerque, Priscilla B S; Soares, Paulo A G; Aragão-Neto, Adelmo C; Albuquerque, Giwellington S; Silva, Luís C N; Lima-Ribeiro, Maria H M; Silva Neto, Jacinto C; Coelho, Luana C B B; Correia, Maria T S; Teixeira, José A C; Carneiro-da-Cunha, Maria G

    2017-09-01

    Galactomannan films from Cassia grandis seeds, associated or not with Cramoll 1,4, were used on topical wounds of rats for the evaluation of the healing process during 14days. All of the films were evaluated by cytotoxic assay, FTIR and lectin hemagglutinating activity (HA). Forty-five male rats were submitted to aseptic dermal wounds (Ø=0.8cm) and divided in groups (n=15): control, test 1, and test 2, treated respectively with saline, galactomannan film and film with immobilized Cramoll 1,4. Macroscopic evaluations were performed by clinical observations and area measurements, and microscopic analysis by histological criteria. Epithelial cell proliferation and differentiation was immunohistochemically assessed using CK14 and PCNA. The presence of CO peaks in the FTIR spectrum confirmed the immobilization of Cramoll 1,4 in the film, while the residual HA confirmed the stability of the lectin after immobilization with 90.94% of the initial HA. The films presented non-cytotoxicity and cell viability exceeding 80%. All of the animals presented re-epithelization around 10days, furthermore test 2 group showed a diffuse response at the stromal tissue and the basal layer associated with wounds completely closed with 11days of experiment. The results suggest a promising use of the films as topical wound curatives. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Green light emission from terbium doped silicon rich silicon oxide films obtained by plasma enhanced chemical vapor deposition.

    PubMed

    Podhorodecki, A; Zatryb, G; Misiewicz, J; Wojcik, J; Wilson, P R J; Mascher, P

    2012-11-30

    The effect of silicon concentration and annealing temperature on terbium luminescence was investigated for thin silicon rich silicon oxide films. The structures were deposited by means of plasma enhanced chemical vapor deposition. The structural properties of these films were investigated by Rutherford backscattering spectrometry, transmission electron microscopy and Raman scattering. The optical properties were investigated by means of photoluminescence and photoluminescence decay spectroscopy. It was found that both the silicon concentration in the film and the annealing temperature have a strong impact on the terbium emission intensity. In this paper, we present a detailed discussion of these issues and determine the optimal silicon concentration and annealing temperature.

  15. Green light emission from terbium doped silicon rich silicon oxide films obtained by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Podhorodecki, A.; Zatryb, G.; Misiewicz, J.; Wojcik, J.; Wilson, P. R. J.; Mascher, P.

    2012-11-01

    The effect of silicon concentration and annealing temperature on terbium luminescence was investigated for thin silicon rich silicon oxide films. The structures were deposited by means of plasma enhanced chemical vapor deposition. The structural properties of these films were investigated by Rutherford backscattering spectrometry, transmission electron microscopy and Raman scattering. The optical properties were investigated by means of photoluminescence and photoluminescence decay spectroscopy. It was found that both the silicon concentration in the film and the annealing temperature have a strong impact on the terbium emission intensity. In this paper, we present a detailed discussion of these issues and determine the optimal silicon concentration and annealing temperature.

  16. Structural, electronic and mechanical properties of CrN: A first principles study

    NASA Astrophysics Data System (ADS)

    Ming, Zhu; Wang, Ke-Hong

    2015-02-01

    The structural stability, electronic, and mechanical properties of chromium nitride (CrN) have been investigated by first-principles calculations within the generalized gradient approximation (GGA). Six different crystal structures of CrN are considered, namely NaCl, CsCl, zinc blende, WC, wurtzite and NiAs. Among the considered structures, NiAs-type structure is energetically more stable than others. The electronic band structure and density of states calculations reveal that these materials exhibit metallic nature. The calculated elastic constants indicate these compounds are mechanically stable in all the considered sturctures. In addition, the related mechanical properties such as bulk modulus, Young's modulus, shear modulus and the Poisson's ratio are also computed.

  17. CrN precipitation and elemental segregation during the decay of expanded austenite

    NASA Astrophysics Data System (ADS)

    Manova, D.; Lotnyk, A.; Mändl, S.; Neumann, H.; Rauschenbach, B.

    2016-06-01

    Nitrogen insertion into austenitic stainless steel at elevated temperatures leads to anomalous fast nitrogen diffusion and the formation of an expanded fcc phase which is known as expanded austenite. In situ x-ray diffraction measurements during low energy nitrogen ion implantation into steel AISI 304 at 475 °C and short annealing at 575 °C were performed in conjunction with transmission electron microscopy investigations. They show the time dependent decay of this expanded phase with coalescing and growing CrN precipitates. There is elemental segregation associated with this decay where Fe is absent very early from the Cr-N containing precipitates. Ni is segregating towards the Fe-rich matrix more slowly. At the same time, the microstructure—decayed phase vs expanded austenite—is visible in SIMS cluster analysis.

  18. Chemically deposited In2S3-Ag2S layers to obtain AgInS2 thin films by thermal annealing

    NASA Astrophysics Data System (ADS)

    Lugo, S.; Peña, Y.; Calixto-Rodriguez, M.; López-Mata, C.; Ramón, M. L.; Gómez, I.; Acosta, A.

    2012-12-01

    AgInS2 thin films were obtained by the annealing of chemical bath deposited In2S3-Ag2S layers at 400 °C in N2 for 1 h. According to the XRD and EDX results the chalcopyrite structure of AgInS2 has been obtained. These films have an optical band gap, Eg, of 1.86 eV and an electrical conductivity value of 1.2 × 10-3 (Ω cm)-1.

  19. Thermal effect on the optical and morphological properties of TiO2 thin films obtained by annealing a Ti metal layer

    NASA Astrophysics Data System (ADS)

    Butt, M. A.; Fomchenkov, S. A.

    2017-01-01

    Titanium metal layers of different thicknesses were deposited on optical glass, quartz and ceramic at 50 °C and 150 °C substrate temperatures with the help of magnetron deposition. The metal layers were converted into a rutile phase of TiO2 at different annealing temperatures. The effect of thermal annealing on the morphology and the refractive index of the thin film was investigated. The film's quality and roughness were found to depend on the substrate's temperature during metal film deposition and on the annealing temperature. The TiO2 thin films obtained on ceramic and glass substrates were seem to show less surface roughness at low substrate temperature as compared to the quartz substrate.

  20. Structural and optical properties of Cu2ZnSn(S,Se)4 films obtained by magnetron sputtering of a Cu2ZnSn alloy target

    NASA Astrophysics Data System (ADS)

    Solovan, M. N.; Mostovoi, A. I.; Bilichuk, S. V.; Pinna, F.; Kovalyuk, T. T.; Brus, V. V.; Maistruk, E. V.; Orletskii, I. G.; Mar'yanchuk, P. D.

    2017-08-01

    Results of the study of structural and optical properties of Cu2ZnSn(S,Se)4 thin films obtained by sulfitation (selenization) of Cu2ZnSn films which were sputtered by target direct current magnetron sputtering using a stoichiometric Cu2ZnSn (99.99%) target are presented. It has been found that Cu2ZnSn(S,Se)4 thin films are polycrystalline with a grain size of 60 nm. The optical bandgap of Cu2ZnSnS4 ( E g op = 1.65 eV) and Cu2ZnSnSe4 ( R g op = 1.2 eV) thin films have been determined.

  1. Kinetics of the electron beam induced crystallization of amorphous ZrO2 films obtained via ion-plasma and laser sputtering

    NASA Astrophysics Data System (ADS)

    Bagmut, A. G.; Beresnev, V. M.

    2017-01-01

    The structure and electron beam induced crystallization kinetics of amorphous ZrO2 films obtained via ion-plasma and laser sputtering were compared. The studies were performed by electron diffraction and transmission electron microscopy with recording video films in situ. The effect of an electron beam on an amorphous film in a vacuum was accompanied by the formation of zirconia microcrystals with an FCC lattice. For laser evaporation, the density of crystallization nuclei was β 109 cm-2, and the characteristic length unit was D 0 0.48 μm. For ion-plasma evaporation, β 1010 cm-2, and D 0 0.06 μm. The kinetic curves of the crystallization of amorphous films were analyzed using the β-variant of the Kolmogorov model as a basis.

  2. Characterization of bismuth selenide (Bi2Se3) thin films obtained by evaporating the hydrothermally synthesised nano-particles

    NASA Astrophysics Data System (ADS)

    Indirajith, R.; Rajalakshmi, M.; Gopalakrishnan, R.; Ramamurthi, K.

    2016-03-01

    Bismuth selenide (Bi2Se3) was synthesized by hydrothermal method at 200 °C and confirmed by powder X-ray diffraction (XRD) studies. The synthesized material was utilized to deposit bismuth selenide thin films at various substrate temperatures (Room Temperature-RT, 150 °C, 250 °C, 350 °C and 450 °C) by electron beam evaporation technique. XRD study confirmed the polycrystalline nature of the deposited Bi2Se3films. Optical transmittance spectra showed that the deposited (at RT) films acquire relatively high average transmittance of 60%in near infrared region (1500-2500 nm). An indirect allowed optical band gap calculated from the absorption edge for the deposited films is ranging from 0.62 to 0.8 eV. Scanning electron and atomic force microscopy analyses reveal the formation of nano-scale sized particles on the surface and that the nature of surface microstructures is influenced by the substrate temperature. Hall measurements showed improved electrical properties, for the films deposited at 350 °C which possess 2.8 times the mobility and 0.9 times the resistivity of the films deposited at RT.

  3. Cast iron cutting with nano TiN and multilayer TiN-CrN coated inserts

    NASA Astrophysics Data System (ADS)

    Perucca, M.; Durante, S.; Semmler, U.; Rüger, C.; Fuentes, G. G.; Almandoz, E.

    2012-09-01

    During the past decade great success has been achieved in the development of duplex and multilayer multi-functional surface systems. Among these surface systems outstanding properties have nanoscale multilayer coatings. Within the framework of the M3-2S project funded in the 7th European Framework Programme, several nanoscale multilayer coatings have been developed and investigated for experimental and industrial validation. This paper shows the performance of TiN and TiN/CrN nanoscale multilayer coatings on WC cutting inserts when machining GJL250 cast iron. The thin films have been deposited by cathodic arc evaporation in an industrial PVD system. The multilayer deposition characteristic and its properties are shown. The inserts have been investigated in systematic cutting experiments of cast iron bars on a turning machine specifically equipped for force measurements, accompanied by wear determination. Furthermore, equivalent experiments have been carried out on an industrial turning unit. Industrial validation criteria have been applied to assess the comparative performance of the coatings. The choice of the material and the machined parts is driven by an interest in automotive applications. The industrial tests show the need to further optimise the multi-scale modelling approach in order to reduce the lead time of the coating development as well as to improve simulation reliability.

  4. Role of N defects in paramagnetic CrN at finite temperatures from first principles

    NASA Astrophysics Data System (ADS)

    Mozafari, E.; Alling, B.; Steneteg, P.; Abrikosov, Igor A.

    2015-03-01

    Simulations of defects in paramagnetic materials at high temperature constitute a formidable challenge to solid-state theory due to the interaction of magnetic disorder, vibrations, and structural relaxations. CrN is a material where these effects are particularly large due to a strong magnetolattice coupling and a tendency for deviations from the nominal 1:1 stoichiometry. In this work, we present a first-principles study of nitrogen vacancies and nitrogen interstitials in CrN at elevated temperature. We report on formation energetics, the geometry of interstitial nitrogen dimers, and the impact on the electronic structure caused by the defects. We find a vacancy formation energy of 2.28 eV with a small effect of temperature, i.e., a formation energy for N interstitial in the form of a <111 > -oriented split bond of 3.77 eV with an increase to 3.97 at 1000 K. Vacancies are found to add three electrons, while split-bond interstitial adds one electron to the conduction band. The band gap of defect-free CrN is smeared out due to vibrations, although it is difficult to draw a conclusion about the exact temperature at which the band gap closes from our calculations. However, it is clear that at 900 K there is a nonzero density of electronic states at the Fermi level. At 300 K, our results indicate a border case where the band gap is about to close.

  5. Some physical investigations on ZnS 1- xSe x films obtained by selenization of ZnS sprayed films using the Boubaker polynomials expansion scheme

    NASA Astrophysics Data System (ADS)

    Fridjine, S.; Touihri, S.; Boubaker, K.; Amlouk, M.

    2010-01-01

    ZnS 1- xSe x thin films have been grown by selenization process, applied to ZnS sprayed thin films deposited on Pyrex glass substrates at 550 °C. The crystal structure and surface morphology were investigated by the XRD technique and by the atomic force microscopy. This structural study shows that selenium-free ( x=0) ZnS thin films, prepared at substrate temperature TS=450 °C, were well crystallized in cubic structure and oriented preferentially along (1 1 1) direction. The thermal and mechanical properties were also investigated using a photothermal protocol along with Vickers hardness measurements. On the other hand, the analyze of the transmittance T( λ) and the reflectance R( λ), optical measurements of these films depicts a decrease in the band gap energy value Eg with an increase in Se content ( x). Indeed, Eg values vary from 3.6 to 3.1 eV.

  6. Post-processing optimization of electrospun submicron poly(3-hydroxybutyrate) fibers to obtain continuous films of interest in food packaging applications.

    PubMed

    Cherpinski, Adriane; Torres-Giner, Sergio; Cabedo, Luis; Lagaron, Jose M

    2017-10-01

    Polyhydroxyalkanoates (PHAs) are one of the most researched family of biodegradable polymers based on renewable materials due to their thermoplastic nature and moisture resistance. The present study was targeted to investigate the preparation and characterization of poly(3-hydroxybutyrate) (PHB) films obtained through the electrospinning technique. To convert them into continuous films and then to increase their application interest in packaging, the electrospun fiber mats were subsequently post-processed by different physical treatments. Thus, the effect of annealing time and cooling method on morphology, molecular order, thermal, optical, mechanical, and barrier properties of the electrospun submicron PHB fibers was studied. Annealing at 160°C, well below the homopolyester melting point, was found to be the minimum temperature at which homogeneous transparent films were produced. The film samples that were cooled slowly after annealing showed the lowest permeability to oxygen, water vapor, and limonene. The optimally post-processed electrospun PHB fibers exhibited similar rigidity to conventional compression-molded PHA films, but with enhanced elongation at break and toughness. Films made by this electrospinning technique have many potential applications, such as in the design of barrier layers, adhesive interlayers, and coatings for fiber- and plastic-based food packaging materials.

  7. Properties of surfactant films in water-in-CO2 microemulsions obtained by small-angle neutron scattering.

    PubMed

    Yan, Ci; Sagisaka, Masanobu; James, Craig; Rogers, Sarah; Alexander, Shirin; Eastoe, Julian

    2014-12-01

    The formation, stability and structural properties of normal liquid phase microemulsions, stabilized by hydrocarbon surfactants, comprising water and hydrocarbon oils can be interpreted in terms of the film bending rigidity (energy) model. Here, this model is tested for unusual water-in-CO2 (w/c) microemulsions, formed at high pressure with supercritical CO2 (sc-CO2) as a solvent and fluorinated surfactants as stabilizers. Hence, it is possible to explore the generality of this model for other types of microemulsions. High Pressure Small-Angle Neutron Scattering (HP-SANS) has been used to study w/c microemulsions, using contrast variation to highlight scattering from the stabilizing fluorinated surfactant films: these data show clear evidence for spherical core-shell structures for the microemulsion droplets. The results extend understanding of w/c microemulsions since previous SANS studies are based only on scattering from water core droplets. Here, detailed structural parameters for the surfactant films, such as thickness and film bending energy, have been extracted from the core-shell SANS profiles revealed by controlled contrast variation. Furthermore, at reduced CO2 densities (∼0.7gcm(-3)), elongated cylindrical droplet structures have been observed, which are uncommon for CO2 microemulsions/emulsions. The implications of the presence of cylindrical micelles and droplets for applications of CO2, and viscosity enhancements are discussed. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. Nanosized films based on multicharged small molecules and oppositely charged polyelectrolytes obtained by simultaneous spray coating of interacting species.

    PubMed

    Lefort, Mathias; Jierry, Loïc; Boulmedais, Fouzia; Benmlih, Karim; Lavalle, Philippe; Senger, Bernard; Voegel, Jean-Claude; Hemmerlé, Joseph; Ponche, Arnaud; Schaaf, Pierre

    2013-11-26

    Simultaneous spraying of polyelectrolytes and small multicharged molecules of opposite charges onto a vertical substrate leads to continuous buildups of organic films. Here, we investigate the rules governing the buildup of two such systems: poly(allylamine hydrochloride)/sodium citrate (PAH/citrate) and PAH/sulfated α-cyclodextrin (PAH/CD-S). Special attention is paid to the film growth rate as a function of the spraying rate ratio of the two constituents. This parameter was varied by increasing the spraying rate of one of the constituents while maintaining constant that of the other. For PAH/CD-S systems, whatever the constituent (PAH or CD-S) whose spraying rate was kept fixed, the film growth rate first increases and passes through a maximum before decreasing when the spraying rate of the other constituent is increased. For PAH/citrate, the film growth rate reaches a plateau value when the spraying rate of citrate is increased while that of PAH is maintained constant, whereas when the spraying rate of citrate is maintained constant and that of PAH is increased, a behavior similar to that of PAH/CD-S is observed. The composition of PAH/CD-S sprayed films determined by X-ray photoelectron spectroscopy is independent of the spraying rate ratio of the two constituents and corresponds to one allylamine for one sulfate group. For PAH/citrate, by increasing the PAH/citrate spraying rate ratio, the carboxylic/nitrogen ratio in the film increases and tends to 1. There is thus always a deficit of carboxylic groups (COO(-) + COOH) with respect to amines (NH2 + NH3(+)). Yet, the ratio (COO(-)/NH3(+)) is always close to 1, ensuring exact charge compensation. The film morphology determined by atomic force microscopy is granular for PAH/CD-S and is smooth and liquid-like for PAH/citrate. A model based on strong (respectively weak) interactions between PAH and CD-S (respectively citrate) is proposed to explain these features.

  9. Correlation between the electrical and structural properties of aluminium-doped ZnO thin films obtained by direct current magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Avril, L.; Guaino, Ph; Maseri, F.; Muthukaruppasamy, K.; Pireaux, J.-J.

    2013-03-01

    High quality Aluminium-doped Zinc Oxide (AZO) films have been obtained by suitably controlling the magnetron sputtering parameters and the substrate temperature. The X-ray diffraction studies showed that a transition of orientation from (002) plane to (103) plane, versus substrate temperature. The surface morphology characterized by scanning electron microscopy and atomic force microscopy exhibited a dense and compact structure at higher temperature. For 200 nm thick AZO films deposited at temperature 530°C, using a ZnO target with an Al2O3 content of 3 wt%, the lowest electrical resistivity is 6.8×10-4 Ω.cm and transmittance is over 85% in the visible spectral region. The conductivity improvement of AZO films was closely related to the crystallanity characterized by the (103) orientation and the densely packed structure.

  10. Quantitative Analysis of Laser Interferometer Waveforms Obtained during Oxygen Reactive-Ion Etching of Thin Polymer Films

    DTIC Science & Technology

    1989-05-12

    reduction factor for reflection from the plasma-polymer (1-2) interface and accounts for spreading of the interface into a transition region. R is a ...the reflectance of the bare substrate after the film is completely removed. The optical effect of f < 1 is a reduction in amplitude of oscillation of R ...also deflects energy out of the specular directions and introduces additional corrections into R . As a first approximation, these corrections can be

  11. Particle morphology as a control of permeation in polymer films obtained from MMA/nBA colloidal dispersions.

    PubMed

    Lestage, David J; Urban, Marek W

    2004-07-20

    The combination of precision-controlled weight loss measurements and spectroscopic surface FT-IR analysis allowed us to identify unique behaviors of poly(methyl methacrylate) (p-MMA). When MMA and n-butyl acrylate (nBA) are polymerized into p-MMA and p-nBA homopolymer blends, MMA/nBA random copolymers, and p-MMA/p-nBA core-shell morphologies, a controlled mobility and stratification of low molecular weight components occurs in films formed from coalesced colloidal dispersions. Due to different affinities toward water, p-MMA and p-nBA are capable of releasing water at different rates, depending upon particle morphological features of initial dispersions. As coalescence progresses, water molecules are released from the high free volume p-nBA particles, whereas p-MMA retains water molecules for the longest time due to its hydrophilic nature. As a result, water losses at extended coalescence times are relatively small for p-MMA. MMA/nBA copolymer and p-MMA/p-nBA blends follow the same trends, although the magnitudes of changes are not as pronounced. The p-MMA/p-nBA core-shell behavior resembles that of p-nBA homopolymer, which is attributed to significantly lower content of the p-MMA component in particles. Annealing of coalesced colloidal films at elevated temperatures causes migration of SDOSS to the F-A interface, but for films containing primarily p-nBA, reverse diffusion back into the bulk is observed. These studies illustrate that the combination of different particle morphologies and temperatures leads to controllable permeation processes through polymeric films. Copyright 2004 American Chemical Society

  12. Impact of In doping on GeTe phase-change materials thin films obtained by means of an innovative plasma enhanced metalorganic chemical vapor deposition process

    NASA Astrophysics Data System (ADS)

    Szkutnik, P. D.; Aoukar, M.; Todorova, V.; Angélidès, L.; Pelissier, B.; Jourde, D.; Michallon, P.; Vallée, C.; Noé, P.

    2017-03-01

    We investigated the deposition and the phase-change properties of In-doped GeTe thin films obtained by plasma enhanced metalorganic chemical vapor deposition and doped with indium using a solid delivery system. The sublimated indium precursor flow rate was calculated as a function of sublimation and deposition parameters. Indium related optical emission recorded by means of optical emission spectroscopy during deposition plasma allowed proposing the dissociation mechanisms of the [In(CH3)2N(CH3)2]2 solid precursor. In particular, using an Ar + H2 + NH3 deposition plasma, sublimated indium molecules are completely dissociated and do not induce by-product contamination by addition of nitrogen or carbon in the films. X-ray photoelectron spectroscopy evidences the formation of In-Te bonds in amorphous as-deposited In-doped GeTe films. The formation of an InTe phase after 400 °C annealing is also evidenced by means of X-ray diffraction analysis. The crystallization temperature Tx, deduced from monitoring of optical reflectivity of In-doped GeTe films with doping up to 11 at. % slightly varies as a function of the In dopant level with a decrease of Tx down to a minimum value for an In doping level of about 6-8 at. %. In this In doping range, the structure of crystallized In-GeTe films changes and is dominated by the presence of a crystalline In2Te3 phase. Finally, the Kissinger activation energy for crystallization Ea is showing to monotonically decrease as the indium content in the GeTe film is increased indicating a promising effect of In doping on crystallization speed in memory devices while keeping a good thermal stability for data retention.

  13. Equation of state of paramagnetic CrN from ab initio molecular dynamics

    NASA Astrophysics Data System (ADS)

    Steneteg, Peter; Alling, Björn; Abrikosov, Igor A.

    2012-04-01

    The equation of state for chromium nitride has been debated in the literature in connection with a proposed collapse of its bulk modulus following the pressure-induced transition from the paramagnetic cubic phase to the antiferromagnetic orthorhombic phase [F. Rivadulla , Nature Mater.1476-112210.1038/nmat2549 8, 947 (2009); B. Alling , Nature Mater.1476-112210.1038/nmat2722 9, 283 (2010)]. Experimentally the measurements are complicated due to the low transition pressure, while theoretically the simulation of magnetic disorder represents a major challenge. Here a first-principles method is suggested for the calculation of thermodynamic properties of magnetic materials in their high-temperature paramagnetic phase. It is based on ab initio molecular dynamics and simultaneous redistributions of the disordered but finite local magnetic moments. We apply this disordered local moments molecular dynamics method to the case of CrN and simulate its equation of state. In particular the debated bulk modulus is calculated in the paramagnetic cubic phase and is shown to be very similar to that of the antiferromagnetic orthorhombic CrN phase for all considered temperatures.

  14. Infrared study of the magnetostructural phase transition in correlated CrN

    NASA Astrophysics Data System (ADS)

    Ebad-Allah, J.; Kugelmann, B.; Rivadulla, F.; Kuntscher, C. A.

    2016-11-01

    We report on the pressure and temperature dependence of the electronic and vibrational properties of polycrystalline CrN studied by optical transmission and reflection measurements over the frequency range 0.012-2.48 eV. The optical conductivity spectrum of CrN at ambient conditions shows a phonon mode at ≈55 meV with a shoulder at ≈69 meV , a pronounced midinfrared absorption band centered at 123 ±2 meV , and a high-energy absorption band at ≈1.5 eV . The absorption bands are discussed in terms of the charge-transfer insulator picture. Following the reflectance spectrum with increasing pressure, the activation of an additional phonon mode above 0.6 GPa indicates the occurrence of a pressure-induced structural phase transition. Furthermore, the absorption spectrum exhibits significant changes in the far-infrared range with decreasing temperature: The phonon mode shows a sudden broadening followed by a splitting below 270 K. These changes observed under pressure or while cooling down can be associated with the magnetostructural phase transition reported previously.

  15. Reduction of the bulk modulus at high pressure in CrN.

    PubMed

    Rivadulla, Francisco; Bañobre-López, Manuel; Quintela, Camilo X; Piñeiro, Alberto; Pardo, Victor; Baldomir, Daniel; López-Quintela, Manuel Arturo; Rivas, José; Ramos, Carlos A; Salva, Horacio; Zhou, Jian-Shi; Goodenough, John B

    2009-12-01

    Nitride coatings are increasingly demanded in the cutting- and machining-tool industry owing to their hardness, thermal stability and resistance to corrosion. These properties derive from strongly covalent bonds; understanding the bonding is a requirement for the design of superhard materials with improved capabilities. Here, we report a pressure-induced cubic-to-orthorhombic transition at approximately 1 GPa in CrN. High-pressure X-ray diffraction and ab initio calculations show an unexpected reduction of the bulk modulus, K0, of about 25% in the high-pressure (lower volume) phase. Our combined theoretical and experimental approach shows that this effect is the result of a large exchange striction due to the approach of the localized Cr:t3 electrons to becoming molecular-orbital electrons in Cr-Cr bonds. The softening of CrN under pressure is a manifestation of a strong competition between different types of chemical bond that are found at a crossover from a localized to a molecular-orbital electronic transition.

  16. Evaluation of electrical properties of Cr/CrN nano-multilayers for electronic applications.

    PubMed

    Marulanda, D M; Olaya, J J; Patiño, E J

    2011-06-01

    The electrical properties of Cr/CrN nano-multilayers produced by Unbalanced Magnetron Sputtering have been studied as a function of bilayer period and total thickness. Two groups of multilayers were produced: in the first group the bilayer period varied between 20 nm, 100 nm and 200 nm with total thickness of 1 microm, and in the second group the bilayer period varied between 25 nm, 50 nm and 100 nm and a total thickness of 100 nm. X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were used in order to investigate the microstructure characteristics of the multilayers, and the Four Point Probe (FPP) method was used to evaluate in-plane and transverse electrical resistivity. XRD results show (111) and (200) orientations for all the CrN coatings and the presence of a multilayer structure was confirmed through SEM studies. Transverse electrical resistivity results show that this property is strongly dependent on the bilayer period.

  17. Morphological and electrical investigations of lead zirconium titanate thin films obtained by sol-gel synthesis on indium tin oxide electrodes

    NASA Astrophysics Data System (ADS)

    Bruno, E.; De Santo, M. P.; Castriota, M.; Marino, S.; Strangi, G.; Cazzanelli, E.; Scaramuzza, N.

    2008-03-01

    In recent years, interest in PbZr0.53Ti0.47O3 (PZT) films has been rapidly increasing due to their technological applications as ferroelectric materials. In the present work, PZT films are obtained by sol-gel synthesis and deposited by spin coating on a transparent conductor substrate, with a perspective application as rectifying layers in asymmetric nematic liquid crystal cells. An extensive investigation is carried out on the effects of different annealing temperatures, with regard to the film texture and to the electric polarization properties, by using low vacuum scanning electron microscopy, atomic force microscopy, and electrostatic force microscopy. It has been observed that PZT domains self-organize into flower-like dendritic structures with a "rosetta" shape at the early stage of crystallization, occurring for annealing temperatures higher than 600 °C; the dimensions of such structures increase versus the annealing temperature. The ferroelectric properties of the PZT films have been related to the observed domains.

  18. Study of electrochemical properties of thin film materials obtained using plasma technologies for production of electrodes for pacemakers

    NASA Astrophysics Data System (ADS)

    Obrezkov, O. I.; Vinogradov, V. P.; Krauz, V. I.; Mozgrin, D. V.; Guseva, I. A.; Andreev, E. S.; Zverev, A. A.; Starostin, A. L.

    2016-09-01

    Studies of thin film materials (TFM) as coatings of tips of pacemaker electrodes implanted into the human heart have been performed. TFM coatings were deposited in vacuum by arc magnetron discharge plasma, by pulsed discharge of “Plasma Focus”, and by electron beam evaporation. Simulation of electric charge transfer to the heart in physiological blood- imitator solution and determination of electrochemical properties of the coatings were carried out. TFM of highly developed surface of contact with tissue was produced by argon plasma spraying of titanium powder with subsequent coating by titanium nitride in vacuum arc assisted by Ti ion implantation. The TFM coatings of pacemaker electrode have passed necessary clinical tests and were used in medical practice. They provide low voltage myocardium stimulation thresholds within the required operating time.

  19. Enhancing absorption in a thin film photovoltaic system with periodic nanostructures obtained by low-cost techniques

    NASA Astrophysics Data System (ADS)

    Le Bris, Arthur; Brudieu, Barbara; Gacoin, Thierry; Teisseire, Jérémie; Sorin, Fabien

    2013-03-01

    Light trapping structures are a promising approach to increase light absorption in ultrathin absorbers of interest for photovoltaic applications. To be integrated within real systems, their fabrication approach need to be simple and scalable, insuring that the gain in efficiency is worth the extra manufacturing steps. Here, we optimize through simulation using a RCWA code, a variety of 1D and 2D structures that can be fabricated with such simple and scalable techniques. In particular, we investigate the effect 1D and 2D gratings fabricated by Nanoimprint Lithography, onto Bragg mirrors that could be made using simple liquid process approaches. The optimized structures exhibit a significant gain in absorption with almost twice as much absorption in the wavelength range 0.5 to 1 micron, compared to a bare absorbing film of GaAs chosen as our reference. We also identify the various phenomena behind the absorption peaks observed and study the angular dependency of absorption with these structures.

  20. Photoresist-Free Fully Self-Patterned Transparent Amorphous Oxide Thin-Film Transistors Obtained by Sol-Gel Process

    NASA Astrophysics Data System (ADS)

    Lim, Hyun Soo; Rim, You Seung; Kim, Hyun Jae

    2014-04-01

    We demonstrated self-patterned solution-processed amorphous oxide semiconductor thin-film transistors (TFTs) using photosensitive sol-gels. The photosensitive sol-gels were synthesized by adding β-diketone compounds, i.e., benzoylacetone and acetylacetone, to sol-gels. The chemically modified photosensitive sol-gels showed a high optical absorption at specific wavelengths due to the formation of metal chelate bonds. Photoreactions of the modified solutions enabled a photoresist-free process. Moreover, Zn-Sn-O with a high Sn ratio, which is hard to wet-etch using conventional photolithography due to its chemical durability, was easily patterned via the self-patterning process. Finally, we fabricated a solution-processed oxide TFT that included fully self-patterned electrodes and an active layer.

  1. Peculiarities in electrical and optical properties of Cu2Zn1- x Mn x SnS4 films obtained by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Orletskii, I. G.; Mar'yanchuk, P. D.; Solovan, M. N.; Maistruk, E. V.; Kozyarskii, D. P.

    2016-03-01

    Thin films of Cu2Zn1- x Mn x SnS4 (0 ≤ x ≤ 1) solid solutions have been obtained for the first time by the spray pyrolysis of aqueous salt solutions (copper, zinc, manganese, and tin chlorides and thiourea) at a temperature of T S = 563 K. The films possess specific electric conductivities within σ ≈ 35-422 Ω-1 cm-1 and optical bandgap width E g op that increases with the manganese content from 1.54 eV ( x = 0) to 2.25 eV ( x = 1). Electrical and optical properties of the obtained films have been studied and analyzed based on a model of polycrystalline materials with grain boundaries. The energy barriers Eb between grains have been determined. The dependence of the bandgap of Cu2Zn1- x Mn x SnS4 (0 ≤ x ≤ 1) solid solutions on the composition has been established using the results of measurements of the optical transmission and absorption coefficients.

  2. Chromium nitride films on stainless steel as bipolar plate for proton exchange membrane fuel cell

    NASA Astrophysics Data System (ADS)

    Wu, Bo; Fu, Yu; Xu, Jun; Lin, Guoqiang; Hou, Ming

    A series of chromium nitride films are prepared on stainless steel substrates by pulsed bias arc ion plating (PBAIP) at different N 2 flow rate as bipolar plates for proton exchange membrane fuel cell (PEMFC). The film chemical composition and phase structure are characterized by X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD). The characterization results indicate that the nitrogen content of deposited films varies from 0.28 to 0.50, and the phase structure changes from mixtures of Cr + Cr 2N, pure Cr 2N through Cr 2N + CrN, to pure CrN. The interfacial contact resistance between samples and carbon paper is measured by Wang's method, and a minimum value of 5.8 mΩ cm 2 is obtained under 1.2 MPa compaction force. The anticorrosion property is examined by potentiodynamic test in the simulated corrosive circumstance of the PEMFC under 25 °C, and the lowest corrosive current density of 5.9 × 10 -7 A cm -2 is obtained at 0.6 V (vs. SCE). Stainless steel substrates coated by the film with lowest contact resistance are chosen as the bipolar plates to assemble cells. An average voltage value of 0.62 V is achieved at 500 mA cm -2, which is close to that of the cell with Ag-plated bipolar plates.

  3. Thermal conductivity and mechanical properties of AlN-based thin films

    NASA Astrophysics Data System (ADS)

    Moraes, V.; Riedl, H.; Rachbauer, R.; Kolozsvári, S.; Ikeda, M.; Prochaska, L.; Paschen, S.; Mayrhofer, P. H.

    2016-06-01

    While many research activities concentrate on mechanical properties and thermal stabilities of protective thin films, only little is known about their thermal properties being essential for the thermal management in various industrial applications. Based on the 3ω-method, we show the influence of Al and Cr on the temperature dependent thermal conductivity of single-phase cubic structured TiN and single-phase wurtzite structured AlN thin films, respectively, and compare them with the results obtained for CrN thin films. The dc sputtered AlN thin films revealed a highly c-axis oriented growth for deposition temperatures of 250 to 700 °C. Their thermal conductivity was found to increase strongly with the film thickness, indicating progressing crystallization of the interface near amorphous regions during the sputtering process. For the 940 nm AlN film, we found a lower boundary for the thermal conductivity of 55.3 W m-1 K-1 . By the substitution of only 10 at. % Al with Cr, κ significantly reduces to ˜5.0 W m-1 K-1 , although the single-phase wurtzite structure is maintained. The single-phase face centered cubic TiN and Ti0.36Al0.64N thin films exhibit κ values of 3.1 W m-1 K-1 and 2.5 W m-1 K-1 , respectively, at room temperature. Hence, also here, the substitutional alloying reduces the thermal conductivity, although at a significantly lower level. Single-phase face centered cubic CrN thin films show κ values of 3.6 W m-1 K-1 . For all nitride based thin films investigated, the thermal conductivity slightly increases with increasing temperature between 200 and 330 K. This rather unusual behavior is based on the high defect density (especially point defects) within the thin films prepared by physical vapor deposition.

  4. Structure, Surface Morphology, and Optical and Electronic Properties of Annealed SnS Thin Films Obtained by CBD

    NASA Astrophysics Data System (ADS)

    Reghima, Meriem; Akkari, Anis; Guasch, Cathy; Turki-Kamoun, Najoua

    2014-09-01

    SnS thin films were initially coated onto Pyrex substrates by the chemical bath deposition (CBD) method and annealed at various temperatures ranging from 200°C to 600°C for 30 min in nitrogen gas. X-ray diffraction (XRD) analysis revealed that a structural transition from face-centered cubic to orthorhombic occurs when the annealing temperature is over 500°C. The surface morphology of all thin layers was investigated by means of scanning electron microscopy and atomic force microscopy. The elemental composition of Sn and S, as measured by energy dispersive spectroscopy, is near the stoichiometric ratio. Optical properties studied by means of transmission and reflection measurements show an increase in the absorption coefficient with increasing annealing temperatures. The band gap energy is close to 1.5 eV, which corresponds to the optimum for photovoltaic applications. Last, the thermally stimulated current measurements show that the electrically active traps located in the band gap disappear after annealing at 500°C. These results suggest that, once again, annealing as a post-deposition treatment may be useful for improving the physical properties of the SnS layers included in photovoltaic applications. Moreover, the thermo-stimulated current method may be of practical relevance to explore the electronic properties of more conventional industrial methods, such as sputtering and chemical vapor deposition.

  5. CrN-based wear resistant hard coatings for machining and forming tools

    NASA Astrophysics Data System (ADS)

    Yang, S.; Cooke, K. E.; Li, X.; McIntosh, F.; Teer, D. G.

    2009-05-01

    Highly wear resistant multicomponent or multilayer hard coatings, based on CrN but incorporating other metals, have been developed using closed field unbalanced magnetron sputter ion plating technology. They are exploited in coated machining and forming tools cutting and forming of a wide range of materials in various application environments. These coatings are characterized by desirable properties including good adhesion, high hardness, high toughness, high wear resistance, high thermal stability and high machining capability for steel. The coatings appear to show almost universal working characteristics under operating conditions of low and high temperature, low and high machining speed, machining of ordinary materials and difficult to machine materials, and machining under lubricated and under minimum lubricant quantity or even dry conditions. These coatings can be used for cutting and for forming tools, for conventional (macro-) machining tools as well as for micromachining tools, either as a single coating or in combination with an advanced, self-lubricating topcoat.

  6. The Influence of New Hydrophobic Silica Nanoparticles on the Surface Properties of the Films Obtained from Bilayer Hybrids

    PubMed Central

    Petcu, Cristian; Purcar, Violeta; Spătaru, Cătălin-Ilie; Alexandrescu, Elvira; Şomoghi, Raluca; Trică, Bogdan; Niţu, Sabina Georgiana; Panaitescu, Denis Mihaela; Donescu, Dan; Jecu, Maria-Luiza

    2017-01-01

    Ultra-hydrophobic bilayer coatings on a glass surface were fabricated by sol–gel process using hexadecyltrimethoxysilane (C16TMS) and tetramethoxysilane (TMOS) (1:4 molar ratio) as precursors. After coating, silica nanoparticles (SiO2 NPs) functionalized with different mono-alkoxy derivatives (methoxytrimethylsilane, TMeMS; ethoxydimethylvinylsilane, DMeVES; ethoxydimethylphenylsilane, DMePhES; and methoxydimethyloctylsilane, DMeC8MS) were added, assuring the microscale roughness on the glass surface. Influences of the functionalized SiO2 NPs and surface morphology on the hydrophobicity of the hybrid films were discussed. The successful functionalization of SiO2 NPs with hydrophobic alkyl groups were confirmed by Fourier transform infrared spectroscopy (FTIR). The thermal stability of hydrophobic SiO2 NPs showed that the degradation of the alkyl groups takes place in the 200–400 °C range. Bilayer coating with C16TMS/TMOS and SiO2 NPs modified with alkoxysilane substituted with C8 alkyl chain (SiO2 NP-C8) has micro/nano structure. Hydrophobicity of functionalized SiO2 NPs-C8 and its higher degree of nanometer-scale roughness gave rise to ultra-hydrophobicity performance for bilayer coating C16TMS/TMOS + SiO2 NPs-C8 (145°), compared to other similar hybrid structures. Our synthesis method for the functionalization of SiO2 NPs is useful for the modification of surface polarity and roughness. PMID:28336881

  7. Gaseous benzene degradation by photocatalysis using ZnO + Zn2TiO4 thin films obtained by sol-gel process.

    PubMed

    Hernández-García, F A; Torres-Delgado, G; Castanedo-Pérez, R; Zelaya-Ángel, O

    2016-07-01

    The benzene pollutant in gaseous phase was successfully degraded by using ZnO + Zn2TiO4 multicomponent oxide thin films as photocatalysts. The films were obtained with different Ti/Zn ratios (0, 0.20, 0.40, 0.45, 0.50, 0.67, 0.84, and 1) by the sol-gel route. The initial level of benzene concentration was 110 ± 10 ppm. The process was carried out under different conditions of relative humidity (RH): 25, 50, and 80 % in a batch-type reactor, at room temperature. The results show benzene degradation near to 95 % at t = 240 min, where the multicomponent oxide semiconductor has a Ti/Zn ratio of 0.67. Meanwhile, with the TiO2 thin films, only a degradation of 70 % was reached at the same measurement conditions. This synergistic effect on the photocatalytic activity is a result of the coupling of both semiconductor oxides. An adverse effect on the photocatalytic activity was observed as the relative humidity increases.

  8. Interface Electrical Properties of Al2O3 Thin Films on Graphene Obtained by Atomic Layer Deposition with an in Situ Seedlike Layer.

    PubMed

    Fisichella, Gabriele; Schilirò, Emanuela; Di Franco, Salvatore; Fiorenza, Patrick; Lo Nigro, Raffaella; Roccaforte, Fabrizio; Ravesi, Sebastiano; Giannazzo, Filippo

    2017-03-01

    High-quality thin insulating films on graphene (Gr) are essential for field-effect transistors (FETs) and other electronics applications of this material. Atomic layer deposition (ALD) is the method of choice to deposit high-κ dielectrics with excellent thickness uniformity and conformal coverage. However, to start the growth on the sp(2) Gr surface, a chemical prefunctionalization or the physical deposition of a seed layer are required, which can effect, to some extent, the electrical properties of Gr. In this paper, we report a detailed morphological, structural, and electrical investigation of Al2O3 thin films grown by a two-steps ALD process on a large area Gr membrane residing on an Al2O3-Si substrate. This process consists of the H2O-activated deposition of a Al2O3 seed layer a few nanometers in thickness, performed in situ at 100 °C, followed by ALD thermal growth of Al2O3 at 250 °C. The optimization of the low-temperature seed layer allowed us to obtain a uniform, conformal, and pinhole-free Al2O3 film on Gr by the second ALD step. Nanoscale-resolution mapping of the current through the dielectric by conductive atomic force microscopy (CAFM) demonstrated an excellent laterally uniformity of the film. Raman spectroscopy measurements indicated that the ALD process does not introduce defects in Gr, whereas it produces a partial compensation of Gr unintentional p-type doping, as confirmed by the increase of Gr sheet resistance (from ∼300 Ω/sq in pristine Gr to ∼1100 Ω/sq after Al2O3 deposition). Analysis of the transfer characteristics of Gr field-effect transistors (GFETs) allowed us to evaluate the relative dielectric permittivity (ε = 7.45) and the breakdown electric field (EBD = 7.4 MV/cm) of the Al2O3 film as well as the transconductance and the holes field-effect mobility (∼1200 cm(2) V(-1) s(-1)). A special focus has been given to the electrical characterization of the Al2O3-Gr interface by the analysis of high frequency capacitance

  9. Films.

    ERIC Educational Resources Information Center

    Philadelphia Board of Education, PA. Div. of Instructional Materials.

    The Affective Curriculum Research Project produced five films and two records during a series of experimental summer programs. The films and records form part of a curriculum designed to teach to the concerns of students. The films were an effort to describe the Philadelphia Cooperative Schools Program, to explain its importance, and to…

  10. Custom-made morphologies of ZnO nanostructured films templated by a poly(styrene-block-ethylene oxide) diblock copolymer obtained by a sol-gel technique.

    PubMed

    Sarkar, Kuhu; Rawolle, Monika; Herzig, Eva M; Wang, Weijia; Buffet, Adeline; Roth, Stephan V; Müller-Buschbaum, Peter

    2013-08-01

    Zinc oxide (ZnO) nanostructured films are synthesized on silicon substrates to form different morphologies that consist of foamlike structures, wormlike aggregates, circular vesicles, and spherical granules. The synthesis involves a sol-gel mechanism coupled with an amphiphilic diblock copolymer poly(styrene-block-ethylene oxide), P(S-b-EO), which acts as a structure-directing template. The ZnO precursor zinc acetate dihydrate (ZAD) is incorporated into the poly(ethylene oxide) block. Different morphologies are obtained by adjusting the weight fractions of the solvents and ZAD. The sizes of the structure in solution for different sol-gels are probed by means of dynamic light scattering. Thin-film samples with ZnO nanostructures are prepared by spin coating and solution casting followed by a calcination step. On the basis of various selected combinations of weight fractions of the ingredients used, a ternary phase diagram is constructed to show the compositional boundaries of the investigated morphologies. The evolution and formation mechanisms of the morphologies are addressed in brief. The surface morphologies of the ZnO nanostructures are studied with SEM. The inner structures of the samples are probed by means of grazing incidence small-angle X-ray scattering to complement the SEM investigations. XRD measurements confirm the crystallization of the ZnO in the wurtzite phase upon calcination of the nanocomposite film in air. The optical properties of ZnO are analyzed by FTIR and UV/Vis spectroscopy. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Nanostaircases: An atomic shadowing instability during epitaxial CrN(001) layer growth

    SciTech Connect

    Frederick, J.R.; Gall, D.

    2005-08-01

    Epitaxial CrN(001) layers, 57 and 230 nm thick, were grown on MgO(001) at 700 deg. C by ultrahigh-vacuum magnetron sputter deposition in pure N{sub 2} discharges. An oblique deposition angle {alpha}=80 deg. was utilized to purposely increase the effect of atomic shadowing on surface morphological and microstructural evolution. The layers are single crystals with a surface morphology that is characterized by dendritic ridge patterns extending along orthogonal <110> directions superposed by square-shaped supermounds with <100> edges. The ridge patterns are due to a two-dimensional growth instability related to a gradient in the adatom density while the supermounds form due to atomic shadowing. The supermounds protrude out of the surface and capture a larger deposition flux than the surrounding layer. This leads to both vertical and lateral growth and the formation of inverted pyramids that are epitaxially embedded in a single crystalline matrix. The inverted pyramids are terminated by 1-3-nm-wide tilted voids that form nanostaircases due to kinetic faceting along orthogonal {l_brace}100{r_brace} planes.

  12. Origins of electronic band gap reduction in Cr/N codoped TiO2.

    PubMed

    Parks Cheney, C; Vilmercati, P; Martin, E W; Chiodi, M; Gavioli, L; Regmi, M; Eres, G; Callcott, T A; Weitering, H H; Mannella, N

    2014-01-24

    Recent studies indicated that noncompensated cation-anion codoping of wide-band-gap oxide semiconductors such as anatase TiO2 significantly reduces the optical band gap and thus strongly enhances the absorption of visible light [W. Zhu et al., Phys. Rev. Lett. 103, 226401 (2009)]. We used soft x-ray spectroscopy to fully determine the location and nature of the impurity levels responsible for the extraordinarily large (∼1 eV) band gap reduction of noncompensated codoped rutile TiO2. It is shown that Cr/N codoping strongly enhances the substitutional N content, compared to single element doping. The band gap reduction is due to the formation of Cr 3d3 levels in the lower half of the gap while the conduction band minimum is comprised of localized Cr 3d and delocalized N 2p states. Band gap reduction and carrier delocalization are critical elements for efficient light-to-current conversion in oxide semiconductors. These findings thus raise the prospect of using codoped oxide semiconductors with specifically engineered electronic properties in a variety of photovoltaic and photocatalytic applications.

  13. Enhanced dopant solubility and visible-light absorption in Cr-N co-doped TiO2 nanoclusters

    SciTech Connect

    Chiodi, Dr Mirco; Cheney, Christine; Vilmercati, Paolo; Cavaliere, Emanuele; Mannella, Norman; Gavioli, Luca; Weitering, Harm H

    2012-01-01

    A major obstacle toward employing TiO2 as an efficient photoactive material is related to its large optical band gap, strongly limiting visible light absorption. Substitutional doping with both donors and acceptors (co-doping) potentially leads to a significant band gap reduction, but the effectiveness of the co-doping approach remains limited by the low solubility of dopants inside TiO2. Here we show that nanostructured Cr and N co-doped TiO2 thin films can be obtained by Supersonic Cluster Beam Deposition (SCBD) with a high concentration of dopants and a strongly reduced band gap. Complementary spectroscopic investigations show that doping effectively occurs into substitutional lattice sites, inducing dopant levels in the gap that are remarkably delocalized. The high surface-to-volume ratio, typical of SCBD nanostructured films, likely facilitates the dopant incorporation. The present results indicate that SCBD films are highly promising photoactive nanophase materials.

  14. Cr, N-Codoped TiO2 Mesoporous Microspheres for Li-ion Rechargeable Batteries with Enhanced Electrochemical Performance

    SciTech Connect

    Bi, Zhonghe; Paranthaman, Mariappan Parans; Guo, Bingkun; Unocic, Raymond R; Meyer III, Harry M; Bridges, Craig A; Sun, Xiao-Guang; Dai, Sheng

    2014-01-01

    Cr,N-codoped TiO2 mesoporous microspheres synthesized using hydrothermal and subsequent nitridation treatment, exhibited higher solubility of nitrogen, and improved electrical conductivity than N-doped TiO2, as anode for Lithium-ion rechargeable batteries, which led to improving charge-discharge capacity at 0.1 C and twice higher rate capability compared to that of nitrogen-doped TiO2 mesoporous microsphere at 10 C

  15. Films

    NASA Astrophysics Data System (ADS)

    Li, Ming; Zhang, Yang; Shao, Yayun; Zeng, Min; Zhang, Zhang; Gao, Xingsen; Lu, Xubing; Liu, J.-M.; Ishiwara, Hiroshi

    2014-09-01

    In this paper, we investigated the microstructure and electrical properties of Bi2SiO5 (BSO) doped SrBi2Ta2O9 (SBT) films deposited by chemical solution deposition. X-ray diffraction observation indicated that the crystalline structures of all the BSO-doped SBT films are nearly the same as those of a pure SBT film. Through BSO doping, the 2Pr and 2Ec values of SBT films were changed from 15.3 μC/cm2 and 138 kV/cm of pure SBT to 1.45 μC/cm2 and 74 kV/cm of 10 wt.% BSO-doped SBT. The dielectric constant at 1 MHz for SBT varied from 199 of pure SBT to 96 of 10 wt.% BSO-doped SBT. The doped SBT films exhibited higher leakage current than that of non-doped SBT films. Nevertheless, all the doped SBT films still had small dielectric loss and low leakage current. Our present work will provide useful insights into the BSO doping effects to the SBT films, and it will be helpful for the material design in the future nonvolatile ferroelectric memories.

  16. Correlation between the structural, morphological, optical, and electrical properties of In2O3 thin films obtained by an ultrasonic spray CVD process

    NASA Astrophysics Data System (ADS)

    Bouhdjer, A.; Attaf, A.; Saidi, H.; Bendjedidi, H.; Benkhetta, Y.; Bouhaf, I.

    2015-08-01

    Indium oxide (In2O3) thin films are successfully deposited on glass substrate at different deposition times by an ultrasonic spray technique using Indium chloride as the precursor solution; the physical properties of these films are characterized by XRD, SEM, and UV-visible. XRD analysis showed that the films are polycrystalline in nature having a cubic crystal structure and symmetry space group Ia3 with a preferred grain orientation along the (222) plane when the deposition time changes from 4 to 10 min, but when the deposition time equals 13 min we found that the majority of grains preferred the (400) plane. The surface morphology of the In2O3 thin films revealed that the shape of grains changes with the change of the preferential growth orientation. The transmittance improvement of In2O3 films was closely related to the good crystalline quality of the films. The optical gap energy is found to increase from 3.46 to 3.79 eV with the increasing of deposition time from 4 to 13 min. The film thickness was varied between 395 and 725 nm. The film grown at 13 min is found to exhibit low resistivity (10-2 Ω·cm), and relatively high transmittance (˜ 93%).

  17. Effect of SiNx diffusion barrier thickness on the structural properties and photocatalytic activity of TiO2 films obtained by sol–gel dip coating and reactive magnetron sputtering

    PubMed Central

    Aubry, Eric; Chaoui, Nouari; Robert, Didier

    2015-01-01

    Summary We investigate the effect of the thickness of the silicon nitride (SiNx) diffusion barrier on the structural and photocatalytic efficiency of TiO2 films obtained with different processes. We show that the structural and photocatalytic efficiency of TiO2 films produced using soft chemistry (sol–gel) and physical methods (reactive sputtering) are affected differentially by the intercalating SiNx diffusion barrier. Increasing the thickness of the SiNx diffusion barrier induced a gradual decrease of the crystallite size of TiO2 films obtained by the sol–gel process. However, TiO2 obtained using the reactive sputtering method showed no dependence on the thickness of the SiNx barrier diffusion. The SiNx barrier diffusion showed a beneficial effect on the photocatalytic efficiency of TiO2 films regardless of the synthesis method used. The proposed mechanism leading to the improvement in the photocatalytic efficiency of the TiO2 films obtained by each process was discussed. PMID:26665074

  18. Effect of SiN x diffusion barrier thickness on the structural properties and photocatalytic activity of TiO2 films obtained by sol-gel dip coating and reactive magnetron sputtering.

    PubMed

    Ghazzal, Mohamed Nawfal; Aubry, Eric; Chaoui, Nouari; Robert, Didier

    2015-01-01

    We investigate the effect of the thickness of the silicon nitride (SiN x ) diffusion barrier on the structural and photocatalytic efficiency of TiO2 films obtained with different processes. We show that the structural and photocatalytic efficiency of TiO2 films produced using soft chemistry (sol-gel) and physical methods (reactive sputtering) are affected differentially by the intercalating SiN x diffusion barrier. Increasing the thickness of the SiN x diffusion barrier induced a gradual decrease of the crystallite size of TiO2 films obtained by the sol-gel process. However, TiO2 obtained using the reactive sputtering method showed no dependence on the thickness of the SiN x barrier diffusion. The SiN x barrier diffusion showed a beneficial effect on the photocatalytic efficiency of TiO2 films regardless of the synthesis method used. The proposed mechanism leading to the improvement in the photocatalytic efficiency of the TiO2 films obtained by each process was discussed.

  19. Effect of nitrogen pressure on the hardness and chemical states of TiAlCrN coatings

    SciTech Connect

    Sullivan, Jonathan F.; Huang Feng; Barnard, John A.; Weaver, Mark L.

    2005-01-01

    TiAlCrN coatings were reactively sputtered from a Ti{sub 0.37}Al{sub 0.51}Cr{sub 0.12} alloy target in this study with a nitrogen partial pressure ranging from 0% to 25% of the total pressure. The effects of the incorporation of nitrogen into the coatings on the hardness, elastic modulus, and chemical state of the metal atoms in the coatings were investigated. The hardness and reduced modulus of the coatings increased with increasing nitrogen partial pressures. The formation of ternary nitrides was inferred from the noticeable difference in the chemical states from those for the corresponding binary nitrides.

  20. Physical properties of Zn /SUB x/ Cd /SUB 1-x/ S films obtained by chemical deposition from the vapor phase in a hydrogen flux

    SciTech Connect

    Razykov, T.M.

    1984-01-01

    The crystal-physics, electrophysical, and photoelectric properties of films of Zn /SUB x/ Cd /SUB 1-x/ S solid solutions over the whole range 0 less than or equal to x less than or equal to 1 are discussed.

  1. Studies of the Cr-CrN coating characteristics formed by means of the magnetron sputtering method from bulk target

    NASA Astrophysics Data System (ADS)

    Kachalin, G. V.; Mednikov, A. F.; Tkhabisimov, A. B.; Sidorov, S. V.

    2017-07-01

    The paper presents the study’s results of ion-plasma chromium based coating characteristics produced on blade steel samples 12Kh13 and EI961 by means of the magnetron sputtering method from the bulk “hot” target. A set of metallographic studies and erosion tests of coatings were carried out using the research equipment URI (unique research installation) “Hydroshock rig Erosion-M” of NRU “MPEI”. Cr-CrN based coatings have a layered structure; thickness of intermediate Cr layers ranges from 0.7 to 1.7 μm, thickness of nitride layers CrN ranges from 1.5 to 4 μm, while the overall coating thickness is 17.0-21.5 μm coating microhardness is 1830-1880 HV0.05. The resulting coatings are found to increase 1.5 times the incubation period duration of erosion wear for steels 12Kh13 and EI961; they reduce the maximum erosion rate 1.3 times, and the steady erosion rate - 1.5 times.

  2. Deposition and characterization of high temperature superconducting YBa2Cu3O7-δ films obtained by DC magnetron sputtering and thermal annealing modification

    NASA Astrophysics Data System (ADS)

    Beshkova, M.; Blagoev, B.; Kovacheva, D.; Mladenov, G.; Nurgaliev, T.

    2008-05-01

    C-axis oriented 100-nm thick YBCO films were deposited on LaAlO3 (100) substrates at substrate temperature of 780°C in a mixed oxygen/argon atmosphere (1:3) of 0.3 Torr by DC off-axis magnetron sputtering. The samples deposited were thermally annealed in oxygen ambient of 600 Torr at 530°C for 40 min. Superconductivity with zero resistance 89.1K was observed for the YBCO films after annealing. These results show that thermal annealing is an important technique for improving the parameters of thin superconducting films. A correlation between the YBCO layers properties before and after annealing was established.

  3. Effect of microstructural evolution on mechanical and tribological properties of Ti-doped DLC films: How was an ultralow friction obtained?

    SciTech Connect

    Zhao, Fei; Li, Hongxuan; Ji, Li; Wang, Yongjun; Liu, Xiaohong; Zhou, Huidi; Chen, Jianmin

    2016-05-15

    This paper examined the evolution of microstructure and its effect on the mechanical and tribological properties of ultralow friction Ti-doped diamondlike carbon (DLC) films, by adjusting the CH{sub 4}/Ar ratio under constant radio frequency discharge power and bias. The Raman, high resolution transmission electron microscopy, atomic force microscope and nanoindentation measurements consistently reveal or indicate the formation of curved graphene sheets or fullerenelike nanostructures with increasing CH{sub 4}/Ar ratio. The superior frictional performance (0.008–0.01) of Ti-DLC films can be attributed to the special microstructure related to the development of embedded fullerenelike nanostructures as a result of incorporation of TiO{sub 2} clusters. The contributing factors include high hardness and cohesion, excellent toughness, high load-bearing capacity, as well as the ultralow shear resistance transform layer and the excellent antioxidation stability brought by the doped Ti.

  4. Device-quality SiO 2 films on InP and Si obtained by operating the pyrolytic CVD reactor in the retardation regime

    NASA Astrophysics Data System (ADS)

    Lakhani, Amir A.

    1984-10-01

    A cold wall atmospheric pressure Chemical Vapor Deposition (CVD) reactor was used to deposit films of SiO 2 at 250°C on n-InP and p-Si substrates. By varying the ratio of oxygen to silane flow rates, the reactor was operated in both the reaction rate controlled and retardation regimes. The insulator-semiconductor interface was evaluated with the aid of high frequency and quasi-static C- V curves. Films deposited on Si in the retardation regime with O 2:SiH 4 = 6 had lowest Qss of 5.8 × 10 11 cm -2 and minimum fast surface state density of 1 × 10 11cm-2eV-1. C- V curves on InP had a hysteresis of 0.5 V, a well defined dip in the quasi-static curve and the accumulation capacitance exhibited no frequency dispersion.

  5. Lightest Isotope of Bh Produced Via the 209Bi(52Cr,n)260BhReaction

    SciTech Connect

    Nelson, Sarah L.; Gregorich, Kenneth E.; Dragojevic, Irena; Garcia, Mitch A.; Gates, Jacklyn M.; Sudowe, Ralf; Nitsche, Heino

    2007-05-07

    The lightest isotope of Bh known was produced in the new {sup 209}Bi({sup 52}Cr,n){sup 260}Bh reaction at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. Positive identification was made by observation of eight correlated alpha particle decay chains in the focal plane detector of the Berkeley Gas-Filled Separator. {sup 260}Bh decays with a 35{sub -9}{sup +19} ms half-life by alpha particle emission mainly by a group at 10.16 MeV. The measured cross section of 59{sub -20}{sup +29} pb is approximately a factor of four larger than compared to recent model predictions. The influences of the N = 152 and Z = 108 shells on alpha decay properties are discussed.

  6. Lightest Isotope of Bh Produced via the {sup 209}Bi({sup 52}Cr,n){sup 260}Bh Reaction

    SciTech Connect

    Nelson, S. L.; Dragojevic, I.; Garcia, M. A.; Gates, J. M.; Nitsche, H.; Gregorich, K. E.; Sudowe, R.

    2008-01-18

    The lightest isotope of Bh was produced in the new {sup 209}Bi({sup 52}Cr,n){sup 260}Bh reaction at the Lawrence Berkeley National Laboratory's 88-Inch Cyclotron. Positive identification was made by observation of eight correlated alpha particle decay chains in the focal plane detector of the Berkeley Gas-Filled Separator. {sup 260}Bh decays with a 35{sub -9}{sup +19} ms half-life by alpha particle emission mainly by a group at 10.16 MeV. The measured cross section of 59{sub -20}{sup +29} pb is compared to model predictions. The influence of the N=152 and Z=108 shells on alpha decay properties is discussed.

  7. Effect of the substrate temperature on the physical properties of molybdenum tri-oxide thin films obtained through the spray pyrolysis technique

    SciTech Connect

    Martinez, H.M.; Torres, J.; Lopez Carreno, L.D.; Rodriguez-Garcia, M.E.

    2013-01-15

    Polycrystalline molybdenum tri-oxide thin films were prepared using the spray pyrolysis technique; a 0.1 M solution of ammonium molybdate tetra-hydrated was used as a precursor. The samples were prepared on Corning glass substrates maintained at temperatures ranging between 423 and 673 K. The samples were characterized through micro Raman, X-ray diffraction, optical transmittance and DC electrical conductivity. The species MoO{sub 3} (H{sub 2}O){sub 2} was found in the sample prepared at a substrate temperature of 423 K. As the substrate temperature rises, the water disappears and the samples crystallize into {alpha}-MoO{sub 3}. The optical gap diminishes as the substrate temperature rises. Two electrical transport mechanisms were found: hopping under 200 K and intrinsic conduction over 200 K. The MoO{sub 3} films' sensitivity was analyzed for CO and H{sub 2}O in the temperature range 160 to 360 K; the results indicate that CO and H{sub 2}O have a reduction character. In all cases, it was found that the sensitivity to CO is lower than that to H{sub 2}O. - Highlights: Black-Right-Pointing-Pointer A low cost technique is used which produces good material. Black-Right-Pointing-Pointer Thin films are prepared using ammonium molybdate tetra hydrated. Black-Right-Pointing-Pointer The control of the physical properties of the samples could be done. Black-Right-Pointing-Pointer A calculation method is proposed to determine the material optical properties. Black-Right-Pointing-Pointer The MoO{sub 3} thin films prepared by spray pyrolysis could be used as gas sensor.

  8. Radiation induced graft copolymerization of n-butyl acrylate onto poly(ethylene terephthalate) (PET) films and thermal properties of the obtained graft copolymer

    NASA Astrophysics Data System (ADS)

    Ping, Xiang; Wang, Mozhen; Ge, Xuewu

    2011-05-01

    n-Butyl acrylate (BA) was successfully grafted onto poly(ethylene terephthalate) (PET) film using simultaneous radiation induced graft copolymerization with gamma rays. When BA concentration ranges from 20% to 30%, the Degree of Grafting (DG), measured by gravimetry and 1H NMR, increases with the monomer concentration and absorbed dose, but decreases with dose rate from 0.83 to 2.53 kGy/h. The maximum DG can reach up to 22.1%. The thermal transition temperatures such as glass-transition temperature ( Tg) and cold-crystallization temperature ( Tcc) of PET in grafted films were little different from those in original PET film, indicating that microphase separation occurred between PBA side chains and PET backbone. This work implied that if PET/elastomers (e.g., acrylate rubber) blends are radiated by high energy gamma rays under a certain condition, PET-g-polyacrylate copolymer may be produced in-situ, which will improve the compatibility between PET and the elastomers so as to improve the integral mechanical properties of PET based engineering plastic.

  9. Obtaining contraceptives.

    PubMed

    Barnes, M; Maxwell, G

    1980-01-01

    A survey of 3 sample urban populations of adolescent males and females was conducted in New Zealand to ascertain whether difficulties in obtaining contraceptives was a major factor contributing toward the high rate of unprotected intercourse among young people. The samples included 246 high school students, 80 university students, and 70 individuals from the general population. There was a 47% refusal rate so the interviewed subjects could not be considered representative of the total populations. Subjects were asked to indicate the degree of embarrassment they would experience in obtaining contraceptives from a variety of sources including some sources which were currently not available. Males felt somewhat more embarrassed in obtaining contraceptives than females. About 1/3 of the males said that they felt embarrassed when obtaining contraceptives at a chemist's shop, especially if they were served by a female shop assistant. Males preferred obtaining contraceptives from sources which provided them with a high degree of privacy and anonymity. Males favored obtaining contraceptives from mail order houses, from vending machines, and from male chemists who made contraceptives available in a special display area. Many males said that they would use the services of a male family planning clinic if such services were made available. Most female methods were available through doctors and females reported less embarrassment in obtaining contraceptives than males. About 1/3 of the females preferred getting contraceptive advice and methods from female doctors, and 1/2 of the females felt it was important to know how the physician felt about contraception before seeking his advice. Current methods of distribution are inadequate and new sources associated with less embarrassment are needed.

  10. Effects of boron addition on a-Si(90)Ge(10):H films obtained by low frequency plasma enhanced chemical vapour deposition.

    PubMed

    Pérez, Arllene M; Renero, Francisco J; Zúñiga, Carlos; Torres, Alfonso; Santiago, César

    2005-06-29

    Optical, structural and electric properties of (a-(Si(90)Ge(10))(1-y)B(y):H) thin film alloys, deposited by low frequency plasma enhanced chemical vapour deposition, are presented. The chemical bonding structure has been studied by IR spectroscopy, while the composition was investigated by Raman spectroscopy. A discussion about boron doping effects, in the composition and bonding of samples, is presented. Transport of carriers has been studied by measurement of the conductivity dependence on temperature, which increases from 10(-3) to 10(1) Ω(-1) cm(-1) when the boron content varies from 0 to 50%. Similarly, the activation energy is between 0.62 and 0.19 eV when the doping increases from 0 to 83%. The optical properties have been determined from the film's optical transmission, using Swanepoel's method. It is shown that the optical gap varies from 1.3 to 0.99 eV.

  11. Data reduction of digitized images processed from calibrated photographic and spectroscopic films obtained from terrestial, rocket and space shuttle telescopic instruments

    NASA Technical Reports Server (NTRS)

    Hammond, Ernest C., Jr.

    1990-01-01

    The Microvax 2 computer, the basic software in VMS, and the Mitsubishi High Speed Disk were received and installed. The digital scanning tunneling microscope is fully installed and operational. A new technique was developed for pseudocolor analysis of the line plot images of a scanning tunneling microscope. Computer studies and mathematical modeling of the empirical data associated with many of the film calibration studies were presented. A gas can follow-up experiment which will be launched in September, on the Space Shuttle STS-50, was prepared and loaded. Papers were presented on the structure of the human hair strand using scanning electron microscopy and x ray analysis and updated research on the annual rings produced by the surf clam of the ocean estuaries of Maryland. Scanning electron microscopic work was conducted by the research team for the study of the Mossbauer and Magnetic Susceptibility Studies on NmNi(4.25)Fe(.85) and its Hydride.

  12. Field-induced spin reorientation in [Fe/Cr ] n multilayers studied by nuclear resonance reflectivity

    NASA Astrophysics Data System (ADS)

    Andreeva, M.; Gupta, A.; Sharma, G.; Kamali, S.; Okada, K.; Yoda, Y.

    2015-10-01

    We present depth-resolved nuclear resonance reflectivity studies of the magnetization evolution in [57Fe(3nm ) /Cr (1.2 nm ) ] 10 multilayer under applied external field. The measurements have been performed at the station BL09XU of SPring-8 at different values of the external field (0-1500 Oe). We apply the joint fit of the delayed reflectivity curves and the time spectra of the nuclear resonance reflectivity measured at different grazing angles for enhancement of the depth resolution and reliability of results. We show that the azimuth angle, which is used in all papers devoted to the magnetization profile determination, has a more complicated physical sense due to the partially coherent averaging of the scattering amplitudes from magnetic lateral domains. We describe how to select the true azimuth angle from the determined "effective azimuth angle." Finally we obtain the noncollinear twisted magnetization depth profiles where the spin-flop state appears sequentially in different 57Fe layers at increasing applied field.

  13. Thin and flexible all-solid supercapacitor prepared from novel single wall carbon nanotubes/polyaniline thin films obtained in liquid-liquid interfaces

    NASA Astrophysics Data System (ADS)

    de Souza, Victor Hugo Rodrigues; Oliveira, Marcela Mohallem; Zarbin, Aldo José Gorgatti

    2014-08-01

    The present work describes for the first time the synthesis and characterization of single wall carbon nanotubes/polyaniline (SWNTs/PAni) nanocomposite thin films in a liquid-liquid interface, as well as the subsequent construction of a flexible all-solid supercapacitor. Different SWNTs/PAni nanocomposites were prepared by varying the ratio of SWNT to aniline, and the samples were characterized by scanning and transmission electron microscopy, Raman and UV-Vis spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The pseudo-capacitive behavior of the nanocomposites was evaluated by charge/discharge galvanostatic measurements. The presence of the SWNTs affected the electronic and vibrational properties of the polyaniline and also improved the pseudo-capacitive behavior of the conducting polymer. A very thin and flexible all-solid device was manufactured using two electrodes (polyethylene terephthalate-PET covered with the SWNT/PAni nanocomposite separated by a H2SO4-PVA gel electrolyte). The pseudo-capacitive behavior was characterized by a volumetric specific capacitance of approximately 76.7 F cm-3, even under mechanical deformation, indicating that this nanocomposite has considerable potential for application in new-generation energy storage devices.

  14. Tribological properties of CrN coatings deposited by nitro-chromizing treatment on AISI D2 steel

    SciTech Connect

    Durmaz, M. Abakay, E.; Sen, U.; Sen, S.; Kilinc, B.

    2015-03-30

    In this work, the wear test of uncoated and chromium nitride coated AISI D2 cold work tool steel against alumina ball realized at 0.1 m/s sliding speeds and under the loads of 2.5N, 5N and 10N. Steel samples were nitrided at 575°C for 8 h in the first step of the coating process, and then chromium nitride coating was performed thermo-reactive deposition technique (TRD) in a powder mixture consisting of ferro-chromium, ammonium chloride and alumina at 1000°C for 2 h. Nitro-chromized samples were characterized by X-Ray diffraction analysis (XRD), scanning electron microscopy (SEM), micro-hardness and ball on disk wear tests. The coating layer formed on the AISI D2 steel was compact and homogeneous. X-ray studies showed that the phase formed in the coated layer is Cr{sub 2}N. The depth of the layer was 8.15 µm. The average hardness of the layer was 2160±15 HV{sub 0.025}. For uncoated and chromium nitride materials, wear rate increased with increasing load. The results of friction coefficient and wear rate of the tested materials showed that the CrN coating presents the lowest results.

  15. Photocatalytic thin films containing TiO2:N nanopowders obtained by the layer-by-layer self-assembling method

    NASA Astrophysics Data System (ADS)

    Rojas-Blanco, L.; Urzúa, M. D.; Ramírez-Bon, R.; Espinoza Beltrán, F. J.

    2012-01-01

    In this work, TiO2-N powders were synthesized by high-energy ball milling, using commercial titanium dioxide (TiO2) in the anatase phase and urea to introduce nitrogen into TiO2 in order to enhance their photocatalytic properties in the visible spectral region. Several samples were prepared by milling a mixture of TiO2-urea during 2, 4, 8, 12 and 24 h and characterized by spectroscopic and analytical techniques. X-ray diffraction (XRD) results showed the coexistence of anatase and high-pressure srilankite TiO2 crystalline phases in the samples. Scanning electron microscopy (SEM) revealed that the grain size of the powder samples decreases to 200 nm at 24 h milling time. UV-Vis diffuse reflectance spectroscopic data showed a clear red-shift in the onset of light absorption from 387 to 469 nm as consequence of nitrogen doping in the samples. The photocatalytic activity of the TiO2-N samples was evaluated by methylene blue degradation under visible light irradiation. It was found that TiO2-N samples had higher photocatalytic activity than undoped TiO2 samples, which could be assigned to the effect of introducing N atoms and XPS results confirm it. Using polyethylenimine (PEI), transparent thin films of TiO2-N nanoparticles were prepared by layer-by-layer self assembly method. UV-visible spectrophotometry was employed in a quantitative manner to monitor the adsorbed mass of TiO2 and PEI after each dip cycle. The adsorption of both TiO2 and PEI showed a saturation dip time of 15 min.

  16. Adhesion analysis for chromium nitride thin films deposited by reactive magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Rusu, F. M.; Merie, V. V.; Pintea, I. M.; Molea, A.

    2016-08-01

    The thin film industry is continuously growing due to the wide range of applications that require the fabrication of advanced components such as sensors, biological implants, micro-electromechanical devices, optical coatings and so on. The selection regarding the deposition materials, as well as the deposition technology influences the properties of the material and determines the suitability of devices for certain real-world applications. This paper is focused on the adhesion force for several chromium nitride thin films obtained by reactive magnetron sputtering. All chromium nitride thin films were deposited on a silicon substrate, the discharge current and the argon flow being kept constant. The main purpose of the paper is to determine the influence of deposition parameters on the adhesion force. Therefore some of the deposition parameters were varied in order to study their effect on the adhesion force. Experimentally, the values of the adhesion force were determined in multiple points for each sample using the spectroscopy in point mode of the atomic force microscope. The obtained values were used to estimate the surface energy of the CrN thin films based on two existing mathematical models for the adhesion force when considering the contact between two bodies.

  17. High Rate Deposition of Thick CrN and Cr2N Coatings Using Modulated Pulse Power (MPP) Magnetron Sputtering

    DTIC Science & Technology

    2010-12-01

    skilled in the art , can overcome many of the above listed disadvantages for the different coating techniques. Sputtering is a very flexible and...J. Pelleg, L.Z. Zevin, S. Lungo and N. Croitoru Thin Solid Films 197 (1991) 117. [32] C. Nouveau , M.A. Djouadi, O...2004) 1306. [52] A.J. Perry. Thin Solid Films 107 (1983)167. [53] M. -A. Djouadi, C. Nouveau , O. Banakh, R. Sanjinés, F. Lévy and G. Nouet

  18. Comparing Cr, and N only doping with (Cr,N)-codoping for enhancing visible light reactivity of TiO2

    SciTech Connect

    Li, Yuan; Wang, Wei; Qiu, Xiaofeng; Meyer III, Harry M; Paranthaman, Mariappan Parans; Eres, Gyula; Zhang, Zhenyu; Gu, Baohua

    2011-01-01

    The photoreactivity of titania (TiO2) nanoclusters with varying levels of N or Cr-doping, or (Cr,N)-codoping, was systematically investigated using photodegradation of methyl orange in aqueous suspensions. The shifting of the TiO2 absorption edge into the visible spectral region that is primarily attributable to band gap narrowing was found to be a reliable metric for estimating the photoreactivity of the doped nanoclusters. Compared to the weak response with undoped and N-doped TiO2, Cr-doping and (Cr, N)-codoping were found to significantly enhance photodegradation of methyl orange under visible light. The initial reaction rates increase from about 0 to above 1.6 10-2 min-1 when the doping concentration of Cr in TiO2 increases from 0 to 5%. In stark contrast, under UV irradiation, doping is not only ineffective but detrimental to the photoreactivity, and all doping including N or Cr only and (Cr, N)-codoping were found to reduce photoreactivity.

  19. Evolution of microstructure and residual stress in sputtered chromium and chromium(x) nitrogen(y) thin films

    NASA Astrophysics Data System (ADS)

    Zhao, Zhibo

    This dissertation examines several fundamental aspects of sputtered films, including chemistry, structure, texture, residual stress and growth morphology. The systems considered are Cr films, CxNy films and Ta films. In the first system, the studies focus on some of the unique microstructural features of Cr films. These films develop well-organized anisotropic microstructures and in-plane texture. A texture turnover with thickness has been revealed. The out-of-plane preferred orientation changes from [110] to [111], and conformally, the in-plane preferred orientations vary as well. A new methodology has been developed, in which an anisotropic in-plane stress distribution in a thin film can be determined. This approach has been applied to the Cr films. The anisotropic stresses in these films are related to the evolution of anisotropic microstructure and in-plane texture. The studies of reactively sputtered CrxNy thin films concentrate on phase formation, microstructure, texture, residual stress and growth morphology. It has been shown that these characteristics are predominantly affected by nitrogen flows. The phases identified in the films include Cr, hexagonal Cr2N, and cubic CrxNy, depending on deposition conditions. The composition of the cubic phase exhibits a wide homogeneity span as indicated by large variations of its lattice parameter. At certain nitrogen flow, a nano-crystalline, N-deficient CrxN y film can be obtained. The CrxNy films deposited at high nitrogen flows develop both out-of-plane texture and in-plane texture. In these films, the elongated grains align crystallographically, forming well-defined microstructures. A new experimental apparatus, which utilizes white beam transmission Laue topography and concomitant radiography, has been developed and applied to study cracking/delamination of thin films. Using the systems, the sputtered Ta and CrN films have been studied, and their failures are related to different types of stress development

  20. Does the additional application of a polylactide film (SurgiWrap) to a lightweight mesh (TiMesh) reduce adhesions after laparoscopic intraperitoneal implantation procedures? Experimental results obtained with the laparoscopic porcine model.

    PubMed

    Schug-Pass, Christine; Sommerer, Florian; Tannapfel, Andrea; Lippert, Hans; Köckerling, Ferdinand

    2008-11-01

    Intraperitoneal repair of incisional hernias using a mesh makes particular demands on the material used. In addition to good integration of the mesh on the parietal side, adhesions to the visceral peritoneum must be avoided. Large-pore, light-weight meshes induce fewer adhesions than heavy-weight polypropylene meshes. Although numerous adhesion-barrier substances for use in combination with a polypropylene mesh have been tested already, mostly in open small animal models, unequivocal benefits have been identified to date in only a few of the experiments. Using the laparoscopic intraperitoneal onlay mesh technique, six pigs were implanted with either a lightweight polypropylene mesh (TiMesh light) or TiMesh plus an adhesion-barrier film made of polylactide (SurgiWrap). After 3 months, the animals underwent a postmortem laparoscopy, and specimens were obtained for planimetric and histologic investigations. No adhesions to intestinal structures were found in any of the animals. Adhesions between the greater omentum and the mesh did not differ significantly between the TiMesh (32%) and SurgiWrap (33.5%) groups. The shrinkage of the mesh's surface area was comparable between the two groups (18% vs. 21%). Histology showed pronounced inflammatory reaction and bridging of scar tissue between the filaments with the use of SurgiWrap versus TiMesh light without film. However, immunohistochemical investigations examining the partial volume of the inflammatory cells, the proliferation marker Ki67, and the apoptotic index at the interface of the filaments all failed to show any significant differences. To avoid adhesions, it is essential that the acute and chronic inflammatory reaction to the implanted material be as small as possible. This requirement is met specifically by the lightweight polypropylene mesh TiMesh light. The additional application of a slowly absorbable adhesion-barrier film made of polylactide (SurgiWrap) does not appear to confer any further benefit.

  1. Comparative studies on the thermal stability and corrosion resistance of CrN, CrSiN, and CrSiN/AlN coatings

    SciTech Connect

    Kim, Gwang Seok; Kim, Sung Min; Lee, Sang Yul; Lee, Bo Young

    2009-07-15

    In this work, three kinds of Cr-based nitride coatings such as monolithic CrN, CrSiN coatings, and multilayered CrSiN/AlN coating with bilayer period of 3.0 nm were deposited on both Si (100) wafer and AISI H13 steel substrates by unbalanced magnetron sputtering. Thermal stability of these coatings was evaluated by annealing the coatings at temperatures between 600 and 1000 degree sign C for 30 min in air. In addition, the corrosion behaviors of these coatings were investigated by potentiodynamic polarization tests in a deaerated 3.5 wt. % NaCl solution at 40 degree sign C. Results from annealing test show the monolithic CrN and CrSiN coatings were completely oxidized after annealed at 800 and 900 degree sign C, and their cross sectional images and atomic force microscopy showed a loose and very porous morphology due to the oxidation. Also, the hardness values of the monolithic CrN and CrSiN coatings were decreased significantly from 22 and 27 GPa to 8 and 14 GPa, respectively. However, the multilayered CrSiN/AlN coating still exhibited a dense microstructure without visible change after annealed at 1000 degree sign C, and moreover, the relatively high hardness of 25 GPa was maintained. The superior thermal stability of the CrSiN/AlN multilayer coating could be attributed to the formation of the dense and stable oxidation barrier consisted of the Al{sub 2}O{sub 3}, Cr{sub 2}O{sub 3}, and amorphous SiO{sub 2} phases near the surface region, which retard the diffusion of oxygen into the coating. In the potentiodynamic polarization test results, it was found that the significantly improved corrosion resistance of the multilayered CrSiN/AlN coating was observed in comparison with those from the monolithic CrN and CrSiN coatings, and its corrosion current density (i{sub corr}) and protective efficiency were measured to be approximately 4.21 {mu}A/cm{sup 2} and 95%, respectively.

  2. Evaluation of the Biofire FilmArray BioThreat-E Test (v2.5) for Rapid Identification of Ebola Virus Disease in Heat-Treated Blood Samples Obtained in Sierra Leone and the United Kingdom

    PubMed Central

    Bailey, Daniel; Matthews, Steven; Lumley, Sarah; Sweed, Angela; Ready, Derren; Eltringham, Gary; Richards, Jade; Vipond, Richard; Lukaszewski, Roman; Payne, Phillippa M.; Aarons, Emma; Simpson, Andrew J.; Hutley, Emma J.; Brooks, Tim

    2015-01-01

    Rapid Ebola virus (EBOV) detection is crucial for appropriate patient management and care. The performance of the FilmArray BioThreat-E test (v2.5) using whole-blood samples was evaluated in Sierra Leone and the United Kingdom and was compared with results generated by a real-time Ebola Zaire PCR reference method. Samples were tested in diagnostic laboratories upon availability, included successive samples from individual patients, and were heat treated to facilitate EBOV inactivation prior to PCR. The BioThreat-E test had a sensitivity of 84% (confidence interval [CI], 64% to 95%) and a specificity of 89% (CI, 73% to 97%) in Sierra Leone (n = 60; 44 patients) and a sensitivity of 75% (CI, 19% to 99%) and a specificity of 100% (CI, 97% to 100%) in the United Kingdom (n = 108; 70 patients) compared to the reference real-time PCR. Statistical analysis (Fisher's exact test) indicated there was no significant difference between the methods at the 99% confidence level in either country. In 9 discrepant results (5 real-time PCR positives and BioThreat-E test negatives and 4 real-time PCR negatives and BioThreat-E test positives), the majority (n = 8) were obtained from samples with an observed or probable low viral load. The FilmArray BioThreat-E test (v2.5) therefore provides an attractive option for laboratories (either in austere field settings or in countries with an advanced technological infrastructure) which do not routinely offer an EBOV diagnostic capability. PMID:26537445

  3. Evaluation of the Biofire FilmArray BioThreat-E Test (v2.5) for Rapid Identification of Ebola Virus Disease in Heat-Treated Blood Samples Obtained in Sierra Leone and the United Kingdom.

    PubMed

    Weller, Simon A; Bailey, Daniel; Matthews, Steven; Lumley, Sarah; Sweed, Angela; Ready, Derren; Eltringham, Gary; Richards, Jade; Vipond, Richard; Lukaszewski, Roman; Payne, Phillippa M; Aarons, Emma; Simpson, Andrew J; Hutley, Emma J; Brooks, Tim

    2016-01-01

    Rapid Ebola virus (EBOV) detection is crucial for appropriate patient management and care. The performance of the FilmArray BioThreat-E test (v2.5) using whole-blood samples was evaluated in Sierra Leone and the United Kingdom and was compared with results generated by a real-time Ebola Zaire PCR reference method. Samples were tested in diagnostic laboratories upon availability, included successive samples from individual patients, and were heat treated to facilitate EBOV inactivation prior to PCR. The BioThreat-E test had a sensitivity of 84% (confidence interval [CI], 64% to 95%) and a specificity of 89% (CI, 73% to 97%) in Sierra Leone (n = 60; 44 patients) and a sensitivity of 75% (CI, 19% to 99%) and a specificity of 100% (CI, 97% to 100%) in the United Kingdom (n = 108; 70 patients) compared to the reference real-time PCR. Statistical analysis (Fisher's exact test) indicated there was no significant difference between the methods at the 99% confidence level in either country. In 9 discrepant results (5 real-time PCR positives and BioThreat-E test negatives and 4 real-time PCR negatives and BioThreat-E test positives), the majority (n = 8) were obtained from samples with an observed or probable low viral load. The FilmArray BioThreat-E test (v2.5) therefore provides an attractive option for laboratories (either in austere field settings or in countries with an advanced technological infrastructure) which do not routinely offer an EBOV diagnostic capability.

  4. Sandblasting induced stress release and enhanced adhesion strength of diamond films deposited on austenite stainless steel

    NASA Astrophysics Data System (ADS)

    Li, Xiao; Ye, Jiansong; Zhang, Hangcheng; Feng, Tao; Chen, Jianqing; Hu, Xiaojun

    2017-08-01

    We firstly used sandblasting to treat austenite stainless steel and then deposited a Cr/CrN interlayer by close field unbalanced magnetron sputtering on it. After that, diamond films were prepared on the interlayer. It is found that the sandblasting process induces phase transition from austenite to martensite in the surface region of the stainless steel, which decreases thermal stress in diamond films due to lower thermal expansion coefficient of martensite phase compared with that of austenite phase. The sandblasting also makes stainless steel's surface rough and the Cr/CrN interlayer film inherits the rough surface. This decreases the carburization extent of the interlayer, increases nucleation density and modifies the stress distribution. Due to lower residual stress and small extent of the interlayer's carburization, the diamond film on sandblast treated austenite stainless steel shows enhanced adhesion strength.

  5. Improved Corrosion Resistance and Mechanical Properties of CrN Hard Coatings with an Atomic Layer Deposited Al2O3 Interlayer.

    PubMed

    Wan, Zhixin; Zhang, Teng Fei; Lee, Han-Bo-Ram; Yang, Ji Hoon; Choi, Woo Chang; Han, Byungchan; Kim, Kwang Ho; Kwon, Se-Hun

    2015-12-09

    A new approach was adopted to improve the corrosion resistance of CrN hard coatings by inserting a Al2O3 layer through atomic layer deposition. The influence of the addition of a Al2O3 interlayer, its thickness, and the position of its insertion on the microstructure, surface roughness, corrosion behavior, and mechanical properties of the coatings was investigated. The results indicated that addition of a dense atomic layer deposited Al2O3 interlayer led to a significant decrease in the average grain size and surface roughness and to greatly improved corrosion resistance and corrosion durability of CrN coatings while maintaining their mechanical properties. Increasing the thickness of the Al2O3 interlayer and altering its insertion position so that it was near the surface of the coating also resulted in superior performance of the coating. The mechanism of this effect can be explained by the dense Al2O3 interlayer acting as a good sealing layer that inhibits charge transfer, diffusion of corrosive substances, and dislocation motion.

  6. Bottom-up diamond nanorod growth in HFCVD from nanocrystalline diamond film as a template-free method

    NASA Astrophysics Data System (ADS)

    Motahari, Hamid; Malekfar, Rasoul

    2017-07-01

    Nanocrystalline diamond (NCD) films are being used in a large number of applications. Also, diamond nanorods (DNRs) exhibit distinctive features that are not present in diamond films, because of the tunable large surface-to-volume ratio and tubular configuration. In this work, we report on the synthesis of DNRs by means of the bottom-up and template-free method from NCD films by the hot filament chemical vapor deposition system. The substrate materials used for diamond deposition were stainless steel (AISI 316) and chromium nitride-coated stainless steel. On both substrates, NCD films and then DNRs have been synthesized. The micro-Raman confirms that the synthesized structure is NCD. In addition, the grazing incident x-ray diffraction pattern confirms the presence of cubic diamond and rhombohedral diamond as a film on the CrN and Cr2N interlayer. Also, the DNRs are encased in an amorphous carbon (a-C) shell. The DNRs are grown on the NCD grains by a bottom-up technology and template-free method. Their orientations are almost random in the diamond thin-film surface. In addition, the density of DNRs on the NCD film for the CrN interlayer is more than for the stainless-steel substrate. The NCD/DNR films are dense, adhesive, continuous, and almost uniform on the CrN-coated stainless-steel substrate.

  7. Effects of interfacial layer structures on crystal structural properties of ZnO films

    SciTech Connect

    Park, J. S.; Minegishi, T.; Lee, S. H.; Im, I. H.; Park, S. H.; Hanada, T.; Goto, T.; Cho, M. W.; Yao, T.; Hong, S. K.; Chang, J. H.

    2008-01-15

    Single crystalline ZnO films were grown on Cr compound buffer layers on (0001) Al{sub 2}O{sub 3} substrates by plasma assisted molecular beam epitaxy. In terms of lattice misfit reduction between ZnO and substrate, the CrN and Cr{sub 2}O{sub 3}/CrN buffers are investigated. The structural and optical qualities of ZnO films suggest the feasibility of Cr compound buffers for high-quality ZnO films growth on (0001) Al{sub 2}O{sub 3} substrates. Moreover, the effects of interfacial structures on selective growth of different polar ZnO films are investigated. Zn-polar ZnO films are grown on the rocksalt CrN buffer and the formation of rhombohedral Cr{sub 2}O{sub 3} results in the growth of O-polar films. The possible mechanism of polarity conversion is proposed. By employing the simple patterning and regrowth procedures, a periodical polarity converted structure in lateral is fabricated. The periodical change of the polarity is clearly confirmed by the polarity sensitive piezo response microscope images and the opposite hysteretic characteristic of the piezo response curves, which are strict evidences for the validity of the polarity controlling method as well as the successful fabrication of the periodical polarity controlled ZnO structure.

  8. Thin Films

    NASA Astrophysics Data System (ADS)

    Khorshidi, Zahra; Bahari, Ali; Gholipur, Reza

    2014-11-01

    Effect of annealing temperature on the characteristics of sol-gel-driven Ta ax La(1- a) x O y thin film spin-coated on Si substrate as a high- k gate dielectric was studied. Ta ax La(1- a) x O y thin films with different amounts of a were prepared (as-prepared samples). X-ray diffraction measurements of the as-prepared samples indicated that Ta0.3 x La0.7 x Oy film had an amorphous structure. Therefore, Ta0.3 x La0.7 x O y film was chosen to continue the present studies. The morphology of Ta0.3 x La0.7 x O y films was studied using scanning electron microscopy and atomic force microscopy techniques. The obtained results showed that the size of grain boundaries on Ta0.3 x La0.7 x O y film surfaces was increased with increasing annealing temperature. Electrical and optical characterizations of the as-prepared and annealed films were investigated as a function of annealing temperature using capacitance-voltage ( C- V) and current density-voltage ( J- V) measurements and the Tauc method. The obtained results demonstrated that Ta0.3 x La0.7 x O y films had high dielectric constant (≈27), wide band gap (≈4.5 eV), and low leakage current density (≈10-6 A/cm2 at 1 V).

  9. X-ray photoelectron spectroscopy method for obtaining a CuIn0.95Ga0.05Se2 thin film: development of technology and a phase composition studying

    NASA Astrophysics Data System (ADS)

    Kalazhokov, Kh Kh; Kalazhokov, Z. Kh; Gadjiev, T. M.; Aliev, M. A.; Ismailov, A. M.; Gadjieva, R. M.; Asvarov, A. Sh; Arslanov, R. K.; Kozyrev, E. N.; Filonenko, V. I.; Askerov, R. O.

    2017-07-01

    A technology of two stage selenezation method in the carrier gas (nitrogen) stream of the reaction component (selenium) has been suggested for the CuIn0.95Ga0.05Se2 thin film growing. Morphology and structure of the CuIn0.95Ga0.05Se2 film have been studied by SEM and XRD methods. Phase compound of film material for the CuIn0.95Ga0.05Se2 semiconductor solution has been studied by X-ray photoelectron spectroscopy method.

  10. Thermal conductivity of nitride films of Ti, Cr, and W deposited by reactive magnetron sputtering

    SciTech Connect

    Jagannadham, Kasichainula

    2015-05-15

    Nitride films of Ti, Cr, and W were deposited using reactive magnetron sputtering from metal targets in argon and nitrogen plasma. TiN films with (200) orientation were achieved on silicon (100) at the substrate temperature of 500 and 600 °C. The films were polycrystalline at lower temperature. An amorphous interface layer was observed between the TiN film and Si wafer deposited at 600 °C. TiN film deposited at 600 °C showed the nitrogen to Ti ratio to be near unity, but films deposited at lower temperature were nitrogen deficient. CrN film with (200) orientation and good stoichiometry was achieved at 600 °C on Si(111) wafer but the film deposited at 500 °C showed cubic CrN and hexagonal Cr{sub 2}N phases with smaller grain size and amorphous back ground in the x-ray diffraction pattern. An amorphous interface layer was not observed in the cubic CrN film on Si(111) deposited at 600 °C. Nitride film of tungsten deposited at 600 °C on Si(100) wafer was nitrogen deficient, contained both cubic W{sub 2}N and hexagonal WN phases with smaller grain size. Nitride films of tungsten deposited at 500 °C were nonstoichiometric and contained cubic W{sub 2}N and unreacted W phases. There was no amorphous phase formed along the interface for the tungsten nitride film deposited at 600 °C on the Si wafer. Thermal conductivity and interface thermal conductance of all the nitride films of Ti, Cr, and W were determined by transient thermoreflectance technique. The thermal conductivity of the films as function of deposition temperature, microstructure, nitrogen stoichiometry and amorphous interaction layer at the interface was determined. Tungsten nitride film containing both cubic and hexagonal phases was found to exhibit much higher thermal conductivity and interface thermal conductance. The amorphous interface layer was found to reduce effective thermal conductivity of TiN and CrN films.

  11. Optimization of chemical vapor deposition diamond films growth on steel: correlation between mechanical properties, structure, and composition.

    PubMed

    Laikhtman, A; Rapoport, L; Perfilyev, V; Moshkovich, A; Akhvlediani, R; Hoffman, A

    2011-09-01

    In the present work we perform optimization of mechanical and crystalline properties of CVD microcrystalline diamond films grown on steel substrates. A chromium-nitride (Cr-N) interlayer had been previously proposed to serve as a buffer for carbon and iron inter-diffusion and as a matching layer for the widely differing expansion coefficients of diamond and steel. However, adhesion and wear as well as crystalline perfection of diamond films are strongly affected by conditions of both Cr-N interlayer preparation and CVD diamond deposition. In this work we assess the effects of two parameters. The first one is the temperature of the Cr-N interlayer preparation: temperatures in the range of 500 degrees C-800 degrees C were used. The second one is diamond film thickness in the 0.5 microm-2 microm range monitored through variation of the deposition time from approximately 30 min to 2 hours. The mechanical properties of so deposited diamond films were investigated. For this purpose, scratch tests were performed at different indentation loads. The friction coefficient and wear loss were assessed. The mechanical and tribological properties were related to structure, composition, and crystalline perfection of diamond films which were extensively analyzed using different microscopic and spectroscopic techniques. It was found that relatively thick diamond film deposited on the Cr-N interlayer prepared at the temperature similar to that of the CVD process has the best mechanical and adhesion strength. This film was stable without visible cracks around the wear track during all scratch tests with different indentation loads. In other cases, cracking and delamination of the films took place at low to moderate indentation loads.

  12. Counter-intuitive experimental evidence on the initiation of radical crack in ceramic thin films at the atomic scale

    NASA Astrophysics Data System (ADS)

    Zhuang, Chunqiang; Li, Zhipeng; Lin, Songsheng

    2015-10-01

    The basic issue related to radial crack in ceramic thin films has received considerable attention due to the fact that the radial crack plays an important role in evaluating the toughness properties of ceramic materials. In this work, an atomic-scale new experimental evidence is clearly presented to reveal the counter-intuitive initiation, the nucleation and the propagation mechanism of the radial crack in Al-Cr-N ceramic thin films.

  13. Counter-intuitive experimental evidence on the initiation of radical crack in ceramic thin films at the atomic scale

    SciTech Connect

    Zhuang, Chunqiang Li, Zhipeng; Lin, Songsheng

    2015-10-15

    The basic issue related to radial crack in ceramic thin films has received considerable attention due to the fact that the radial crack plays an important role in evaluating the toughness properties of ceramic materials. In this work, an atomic-scale new experimental evidence is clearly presented to reveal the counter-intuitive initiation, the nucleation and the propagation mechanism of the radial crack in Al-Cr-N ceramic thin films.

  14. Growth and characterization of thin oriented Co{sub 3}O{sub 4} (111) films obtained by decomposition of layered cobaltates Na{sub x}CoO{sub 2}

    SciTech Connect

    Buršík, Josef; Soroka, Miroslav; Kužel, Radomír; Mika, Filip

    2015-07-15

    The formation and structural characterization of highly (111)-oriented Co{sub 3}O{sub 4} films prepared by a novel procedure from weakly (001)-oriented Na{sub x}CoO{sub 2} is reported. The Na{sub x}CoO{sub 2} films were deposited on both single crystal and amorphous substrates by chemical solution deposition (CSD) method and crystallized at 700 °C. Subsequently they were transformed into (111)-oriented Co{sub 3}O{sub 4} phase during post-growth annealing at 900 °C. The degree of preferred orientation in Co{sub 3}O{sub 4}, which was determined by phi-scan and pole figure measurements, depends on the content of Na in the starting Na{sub x}CoO{sub 2} phase. Surface morphology of the films was investigated using electron microscopy and atomic force microscopy. - Graphical abstract: Structure of growth twins and possible O{sup 2−} stacking sequences in (111)-oriented Co{sub 3}O{sub 4} thin films on α-Al{sub 2}O{sub 3}(001) prepared by chemical solution deposition through the transformation of (001)-oriented Na{sub x}CoO{sub 2} thin film. - Highlights: • Single phase Co{sub 3}O{sub 4} thin films was prepared by means of chemical solution deposition. • Conditions for γ-Na{sub x}CoO{sub 2} to Co{sub 3}O{sub 4} transformation were optimized. • Growth twinning of Co{sub 3}O{sub 4} films due to two possible O{sup 2−} stacking sequences. • Growth with (pseudo)epitaxial relation Co{sub 3}O{sub 4} (111)[−121]//α-Al{sub 2}O{sub 3} (001)[10−10].

  15. Cu2ZnSnS4 thin films obtained by sulfurization of evaporated Cu2SnS3 and ZnS layers: Influence of the ternary precursor features

    NASA Astrophysics Data System (ADS)

    Robles, V.; Guillén, C.; Trigo, J. F.; Herrero, J.

    2017-04-01

    Cu2ZnSnS4 (CZTS) thin films have been grown by sulfurization of Cu2SnS3 (CTS) and ZnS layers evaporated on glass substrates. Four CTS precursor films have been tested, with two different atomic compositions (Cu/Sn = 1.7 and Cu/Sn = 2.1) and substrate temperatures (350 and 450 °C), together with analogous ZnS layers deposited by maintaining the substrate at 200 °C. The sulfurization of the CTS and ZnS stacked layers was performed at 500 °C during 1 h. The evolution of the crystalline structure, morphology, optical and electrical properties from each CTS precursor to the CZTS compound has been studied, especially the influence of the ternary precursor features on the quaternary film characteristics. The kesterite structure has been identified after sulfurization of the various samples, with main (112) orientation and mean crystallite sizes S112 = 40-56 nm, being higher for the Cu-poor compositions. The CZTS average roughness has varied in a wide interval Ra = 8-66 nm, being directly related to the CTS precursor layer, which becomes rougher for a higher deposition temperature or Cu content. Besides, the band gap energy and the electrical resistivity of the CZTS films have changed in the ranges Eg = 1.54-1.64 eV and ρ = 0.2-40 Ωcm, both decreasing when the Cu content and/or the surface roughness increase.

  16. Influence of Ar/Kr ratio and pulse parameters in a Cr-N high power pulse magnetron sputtering process on plasma and coating properties

    SciTech Connect

    Bobzin, Kirsten; Bagcivan, Nazlim; Theiß, Sebastian; Trieschmann, Jan; Brugnara, Ricardo Henrique; Preissing, Sven; Hecimovic, Ante

    2014-03-15

    Krypton is sometimes used in physical vapor deposition processes due to its greater atomic mass and size compared to argon, which leads to a lower gas incorporation and may have beneficial effects on kinetics of the coating growth. In this paper, the authors investigate the plasma composition and properties of deposited high power pulse magnetron sputtering Cr-N coatings for discharges with various Ar/Kr ratios and for various pulse lengths of 40 μs, 80 μs, and 200 μs, keeping the average discharge power constant. The results show that an addition of Kr influences the discharge process by altering the ignition and peak values of the discharge current. This influences the metal ion generation and growth conditions on the substrate by reducing the nucleation site densities, leading to a predominantly columnar grow. However, the deposition rate is highest for an Ar/Kr ratio of 120/80. The integral of the metal ion and atom emission exhibits the same trend, having a maximum for Ar/Kr ratio of 120/80. By decreasing the pulse length, the deposition rate of coatings decreases, while the hardness increases.

  17. Local pressure components and interfacial tensions of a liquid film in the vicinity of a solid surface with a nanometer-scale slit pore obtained by the perturbative method

    SciTech Connect

    Fujiwara, K.; Shibahara, M.

    2015-03-07

    A classical molecular dynamics simulation was conducted for a liquid-solid interfacial system with a nanometer-scale slit pore in order to reveal local thermodynamic states: local pressure components and interfacial tensions of a liquid film in the vicinity of the slit. The simulation also examined the transition mechanism between the two states of the liquid film: (a) liquid film on the slit and (b) liquid film in the slit, based on the local thermodynamic quantities from a molecular point of view. An instantaneous expression of the local pressure components and interfacial tensions, which is based on a volume perturbation, was presented to investigate time-dependent phenomena in molecular dynamics simulations. The interactions between the particles were described by the 12-6 Lennard-Jones potential, and effects of the fluid-solid interaction intensity on the local pressure components and interfacial tensions of the fluid in the vicinity of the slit were examined in detail by the presented perturbative method. The results revealed that the local pressure components tangential to the solid surface in the vicinity of the 1st fluid layer from the solid surface are different in a two dimensional plane, and the difference became pronounced in the vicinity of the corner of the slit, for cases where the fluid-solid interaction intensities are relatively strong. The results for the local interfacial tensions of the fluid inside the slit suggested that the local interfacial tensions in the vicinity of the 2nd and 3rd layers of the solid atoms from the entrance of the slit act as a trigger for the transition between the two states under the influence of a varying fluid-solid interaction.

  18. Stainless Steel Bipolar Plates Deposited with Multilayer Films for PEMFC Applications

    NASA Astrophysics Data System (ADS)

    Cho, Hyun; Yun, Young-Hoon

    2013-08-01

    A chromium nitride (CrN, Cr2N)/chromium (Cr)/indium-tin-oxide (ITO) system and a gold (Au)/titanium (Ti) system were separately deposited using a sputtering method and an E-beam method, respectively, onto stainless steel 316 and 304 plates. The XRD patterns of the deposited stainless steel plates showed the crystalline phase of typical indium-tin oxide and of metallic phases, such as chromium, gold, and the metal substrate, as well as those of external chromium nitride films. The nitride films were composed of two metal nitride phases that consisted of CrN and Cr2N compounds. The surface morphologies of the modified stainless steel bipolar plates were observed using atomic force microscopy and FE-SEM. The chromium nitride (CrN, Cr2N)/chromium (Cr)/indium-tin-oxide (ITO) multilayer that was formed on the stainless steel plates had a surface microstructural morphology that consisted of fine columnar grains 10 nm in diameter and 60 nm in length. The external gold films that were formed on the stainless steel plates had a grain microstructure approximately 100 nm in diameter. The grain size of the external surface of the stainless steel plates with the gold (Au)/titanium (Ti) system increased with increasing gold film thickness. The electrical resistances and water contact angles of the stainless steel bipolar plates that were covered with the multilayer films were examined as a function of the thickness of the ITO film or of the external gold film. In the corrosion test, ICP-MS results indicated that the gold (Au)/titanium (Ti) films showed relatively excellent chemical stability after exposure to H2SO4 solution with pH 3 at 80 °C.

  19. Wear Resistance of Coating Films on Hob Teeth

    NASA Astrophysics Data System (ADS)

    Umezaki, Yoji; Funaki, Yoshiyuki; Kurokawa, Syuhei; Ohnishi, Osamu; Doi, Toshiro

    The wear resistance of coating films on hob teeth is investigated through the simulated hobbing tests with a flytool. The coating films on hob teeth are titanium family ceramics such as TiN, TiCN, TiSiN and TiAlN and aluminum chromium family ceramics such as AlCrN and AlCrSiN. The wear of coated tools is shown about film thickness, film materials, ingredient ratio in a film component and the oxidization of coating films. The oxidization is clarified from a result of the influence on the crater wear progress through wear cutting tests in atmosphere of nitrogen gas or oxygen gas. The oxidization of TiAlN coating films produces oxide products on the tool rake face, and this oxidation relates to the amount of crater wear. The increase of aluminum concentration in the TiAlN film improves the crater wear resistance in air atmosphere, while it has a reverse effect in nitrogen gases. The AlCrSiN film has effective wear resistance against the abrasive wear and/or oxidization wear. The oxidation film formed on the AlCrSiN film is very firm and this suppresses the oxidation wear on the rake face and works against the abrasive wear advantageously.

  20. Chemical and thermodynamic influences in ion beam assisted thin film synthesis

    NASA Astrophysics Data System (ADS)

    Ensinger, W.

    1994-02-01

    The main parameter of ion beam assisted deposition of compound films is the ratio γ of impacting ions to condensing atoms. It determines the energy input into the growing film and influences the composition of the film. When highly reactive elements such as transition metals are involved in the process, the elemental composition of the film may also be influenced by the presence of reactive gas molecules, and their partial pressure in the vacuum system. The corresponding process parameter is the ratio δ of impinging gas molecules to condensing atoms. In this case, the final phase and elemental composition of the film is strongly affected by chemical and thermodynamic influences. This is shown by a comparison of ion beam assisted deposition of TiN, VN and CrN. The according metal was evaporated and the growing film irradiated with energetic nitrogen ions. The physical process parameters such as evaporation rate, ion current density and ion energy were the same for all three elements. X-ray phase analysis shows that, whereas it is easily possible to synthesize TiN over a wide range of γ-values, CrN requires a very high irradiation intensity or high γ-value to be deposited as a monophase. VN is intermediate in its behaviour between TiN and CrN. This result is in accordance with the reactivity of the metals towards nitrogen gas and the thermodynamic stability of the resulting nitride. It shows that besides the physical parameters of the process chemical driving forces also play an important role.

  1. VACUUM DEPOSITION OF THIN FILMS,

    DTIC Science & Technology

    The book deals with methods of obtaining and processing thin films , methods of measuring the deposition rate and thickness of thin-film layers, and...the main fields of application of thin films . Vacuum requirements and the requirements for the composition of the residual medium in thermal...evaporation and cathode sputtering are given, and modern methods of producing and measuring vacuums and the equipment used in obtaining thin films are described. (Author)

  2. Film Reviews.

    ERIC Educational Resources Information Center

    Lance, Larry M.; Atwater, Lynn

    1987-01-01

    Reviews four Human Sexuality films and videos. These are: "Personal Decisions" (Planned Parenthood Federation of America, 1985); "The Touch Film" (Sterling Production, 1986); "Rethinking Rape" (Film Distribution Center, 1985); "Not A Love Story" (National Film Board of Canada, 1981). (AEM)

  3. Process For Cutting Polymers Electrolyte Multi-Layer Batteries And Batteries Obtained Thereby

    DOEpatents

    Gauthier, Michel; Lessard, Ginette; Dussault, Gaston; Rouillard, Roger; Simoneau, Martin; Miller, Alan Paul

    2003-09-09

    A stacking of battery laminate is prepared, each battery consisting of anode, polymer electrolyte, cathode films and possibly an insulating film, under conditions suitable to constitute a rigid monoblock assembly, in which the films are unitary with one another. The assembly obtained is thereafter cut in predetermined shape by using a mechanical device without macroscopic deformation of the films constituting the assembly and without inducing permanent short circuits. The battery which is obtained after cutting includes at least one end which appears as a uniform cut, the various films constituting the assembly having undergone no macroscopic deformation, the edges of the films of the anode including an electronically insulating passivation film.

  4. [Erythromycin ethylsuccinate obtaining possibilities].

    PubMed

    Stan, Cătălina Daniela; Stefanache, Alina; Tântaru, Gladiola; Poiată, Antonia; Dumitrache, M; Diaconu, D E; Profire, Lenuţa

    2008-01-01

    In this study we tried to improve the erythromycin ethylsuccinate obtaining, having in view to separate the erythromycin ester by crystallization in water. The erythromycin acylation and the erythromycin ethylsuccinate crystallization were realized, following the next steps: 1. the acylation of the erythromycin with a methylene chloride solution of monoethylsuccinyl chloride, at 25-28 degrees C for 3 hours in the presence of NaHCO3; 2. the transfer of the erythromycin ethylsuccinate from methylene chloride solution in acetone solution by distillation of mixture methylene chloride: acetone 1:1 at 25-28 degrees C; 3. erythromycin ethylsuccinate separation by crystallization in water at pH = 8-8.5 and 5 degrees C for 90 minutes. The quality control for the erythromycin ester was performed according to the Xth edition of Romanian Pharmacopoeia standards using national standard for erythromycin ethylsuccinate and national standard for erythromycin with an activity of 1: 937 U and 2.02% humidity. The Micrococcus luteus ATCC 9341 was used as a test microorganism and a thin layer cromatography was performed for qualitative control. 13.1 g of erythromycin ethylsuccinate were obtained with an output of the process of 82.02%. Using water for the separation of erythromycin ethylsuccinate the output of the process is greater (82.02%) than in case of using petroleum ether (74.14%) or hexane (80.25%). The thin layer cromatography revealed an Rf = 0.56 and the microbiological activity of the erythromycin ethylsuccinate was 98.7% compared with the standard. Using water instead of hexane or petroleum ether is gainful for the separation of erythromycin ethylsuccinate from the reaction medium. The obtained erythromycin ethylsuccinate corresponds to the Xth edition of Romanian Pharmacopoeia standards. So, the raw materials consumption is decreased, the costs are cut down, the obtained product purity is high and the output of the process is greater.

  5. Obtaining and maintaining funding

    SciTech Connect

    Beverly Hartline

    1996-04-01

    Obtaining and maintaining funding is important for individuals, groups, institutions, and fields. This challenge is easier during times of abundant and growing resources than it is now, when funding is tight and shrinking. Thus, to obtain and maintain funding will require: maintaining healthy funding levels for all of science; maintaining healthy funding levels for the field(s) you work in; and competing successfully for the available funds. Everyone should pay attention to the overall prospects for science funding and dedicate some effort to working with others to grow the constituency for science. Public support is likely an important prerequisite for keeping future science budgets high. In this context, researchers should share with society at large the benefits of their research, so that taxpayers can see and appreciate some return from the federal investment in science. Assuming this effort is successful, and there continue to be government and private organizations with substantial resources to invest in research, what can the individual investigator do to improve her chances? She can be clear about her goal(s) and carefully plan her effort to make maximum progress for minimum resources, especially early in her career while she is establishing a solid professional reputation. Specific useful strategies include: brainstorm funding options and select the most promising one(s); be persistent but flexible, responsive to new information and changing circumstances; provide value and assistance to prospective funding sources both before and after receiving funding; know the funding agents and what their goals are, they are the customers; promise a lot and always deliver more; build partnerships and collaboration to leverage interest and resources; and develop capabilities and ideas with a promising, irresistible future. There is no guarantee of success. For the best chances, consistently contribute positively and productively in all your efforts, and continue to

  6. Thermally processed keratin films

    NASA Astrophysics Data System (ADS)

    Barone, Justin; Schmidt, Walter

    2004-03-01

    Keratin obtained from poultry feathers is blended with -OH containing second phases. Films are prepared by pressing the blended keratin at temperatures concurrent with typical polymer processing temperatures. The films are completely cohesive as opposed to partially cohesive if pressed under the same conditions without blending. The films are "tough" and the mechanical properties show similarities to the properties of commercially available commodity thermoplastics. The keratin films are produced in a few minutes without reducing or oxidizing agents. The mobility of the keratin chains during blending is shown to relate to the serine (S), threonine (T), and tyrosine (Y) contents in the amino acid sequence relative to cystine (C).

  7. Polyheterocycle Langmuir-Blodgett Films

    DTIC Science & Technology

    1989-05-29

    3-alkyl thiophene) and Stearic acid LB films. Thc oricntation of single- and Multi-laycr films on platinum substrates have bccn studicd by Ncar Edgc...not surface active. The LB films were obtained by spreading a mixture of the poly(3-alkvl thiophenes) and stearic acid (C,71-5 COOH ) onto the water

  8. Capacitor film surface assessment studies

    NASA Astrophysics Data System (ADS)

    Galperin, I.; White, W.

    1985-02-01

    In the present investigation of the optical surface of the three widely used, biaxially oriented capacitor films, polypropylene, polyvinylidene fluoride, and polyester, with attention to film surface defects and thickness variation, the defects and their rate of occurrence proved traceable in terms of polymer structure, chemical grouping, and fabrication processing. Film thickness variation was small, yet differed for each film type. Film breakdown voltages have been determined, and alternative causes for the voltage values obtained are proposed. A reciprocal relation is noted between the film breakdown voltage and the dielectric constant.

  9. Response of duplex Cr(N)/S and Cr(C)/S coatings on 316L stainless steel to tribocorrosion in 0.89% NaCl solution under plastic contact conditions.

    PubMed

    Sun, Y; Dearnley, P A; Mallia, Bertram

    2017-08-01

    Two duplex coatings, Cr(N)/S and Cr(C)/S, were deposited on 316 L stainless steel by magnetron sputtering. The effectiveness of these duplex coatings in improving the tribocorrosion behavior of medical alloys under elastic contact conditions has been demonstrated in a recent publication. The present work focused on the response of these duplex coatings to tribocorrosion under plastic contact conditions. Tribocorrosion tests were conducted in 0.89% NaCl solution at 37°C at an initial contact pressure of 740 MPa and under unidirectional sliding conditions for sliding duration up to 24 h. The results showed that during sliding in the corrosive solution, the duplex coatings were plastically deformed into the substrate to a depth about 1 μm. The Cr(C)/S duplex coating had sufficient ductility to accommodate the deformation without cracking, such that it was worn through gradually, leading to the gradual increase in open circuit potential (OCP) and coefficient of friction (COF). On the other hand, the Cr(N)/S duplex coating suffered from cracking at all tested potentials, leading to coating blistering after prolonged sliding at OCP and stable pit formation in the substrate beneath the coating at applied anodic potentials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1503-1513, 2017. © 2016 Wiley Periodicals, Inc.

  10. Obtaining an equivalent beam

    NASA Technical Reports Server (NTRS)

    Butler, Thomas G.

    1990-01-01

    In modeling a complex structure the researcher was faced with a component that would have logical appeal if it were modeled as a beam. The structure was a mast of a robot controlled gantry crane. The structure up to this point already had a large number of degrees of freedom, so the idea of conserving grid points by modeling the mast as a beam was attractive. The researcher decided to make a separate problem of of the mast and model it in three dimensions with plates, then extract the equivalent beam properties by setting up the loading to simulate beam-like deformation and constraints. The results could then be used to represent the mast as a beam in the full model. A comparison was made of properties derived from models of different constraints versus manual calculations. The researcher shows that the three-dimensional model is ineffective in trying to conform to the requirements of an equivalent beam representation. If a full 3-D plate model were used in the complete representation of the crane structure, good results would be obtained. Since the attempt is to economize on the size of the model, a better way to achieve the same results is to use substructuring and condense the mast to equivalent end boundary and intermediate mass points.

  11. Structural and magnetic phase transitions in chromium nitride thin films grown by rf nitrogen plasma molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Alam, Khan; Disseler, Steven M.; Ratcliff, William D.; Borchers, Julie A.; Ponce-Pérez, Rodrigo; Cocoletzi, Gregorio H.; Takeuchi, Noboru; Foley, Andrew; Richard, Andrea; Ingram, David C.; Smith, Arthur R.

    2017-09-01

    A magnetostructural phase transition is investigated in single-crystal chromium nitride (CrN) thin films grown by rf plasma molecular beam epitaxy on MgO(001) substrates. While still within the vacuum environment following molecular beam epitaxy growth, in situ low-temperature scanning tunneling microscopy, and in situ variable low-temperature reflection high-energy electron diffraction are applied, revealing an atomically smooth and metallic CrN(001) surface, and an in-plane structural transition from 1 ×1 (primitive CrN unit cell) to √{2 }×√{2 }-R 45∘ with a transition temperature of (278 ±3 ) K, respectively. Ex situ temperature-dependent measurements using neutron diffraction are also performed, looking at the structural peaks and likewise revealing a first-order structural transition along the [111] out-of-plane direction, with transition temperatures of (268 ± 3) K. Turning to the magnetic peaks, neutron diffraction confirms a clear magnetic transition from paramagnetic at room temperature to antiferromagnetic at low temperatures with a sharp, first-order phase transition and a Néel temperature of (270 ±2 ) K or (280 ±2 ) K for two different films. In addition to the experimental measurements of structural and magnetic ordering, we also discuss results from first-principles theoretical calculations which explore various possible magnetostructural models.

  12. Comprehensive study of the conditions for obtaining hydrogenated amorphous erbium- and oxygen-doped silicon suboxide films, a-SiO{sub x}:H Left-Pointing-Angle-Bracket Er,O Right-Pointing-Angle-Bracket , by dc-magnetron deposition

    SciTech Connect

    Undalov, Yu. K. Terukov, E. I.; Gusev, O. B.; Lebedev, V. M.; Trapeznikova, I. N.

    2011-12-15

    The results of a comprehensive study of the conditions for growing a-SiO{sub x}:H Left-Pointing-Angle-Bracket Er,O Right-Pointing-Angle-Bracket films are presented. The effect of the composition of various erbium-containing targets (a-SiO{sub x}:H , ErO{sub x}, Er{sub 2}SiO{sub 5}, Er{sub 2}O{sub 3}, and Er), substrate temperature, and annealing temperatures in argon, air, and under conditions of SiH{sub 4} + Ar + O{sub 2} plasma glow is studied. In order to obtain a-SiO{sub x}:H Left-Pointing-Angle-Bracket Er,O Right-Pointing-Angle-Bracket films with the highest photoluminescence intensity of erbium ions, it is recommended for the following technological conditions to be used: the substrate holder should be insulated from dc-magnetron electrodes and the working gas mixture should include silane, argon, and oxygen. Single-crystal silicon and metal erbium should be used as targets. The erbium target should be placed only in the Si-target erosion zone.

  13. Transition-metal-nitride-based thin films as novel energy harvesting materials.

    PubMed

    Eklund, Per; Kerdsongpanya, Sit; Alling, Björn

    2016-05-14

    The last few years have seen a rise in the interest in early transition-metal and rare-earth nitrides, primarily based on ScN and CrN, for energy harvesting by thermoelectricity and piezoelectricity. This is because of a number of important advances, among those the discoveries of exceptionally high piezoelectric coupling coefficient in (Sc,Al)N alloys and of high thermoelectric power factors of ScN-based and CrN-based thin films. These materials also constitute well-defined model systems for investigating thermodynamics of mixing for alloying and nanostructural design for optimization of phase stability and band structure. These features have implications for and can be used for tailoring of thermoelectric and piezoelectric properties. In this highlight article, we review the ScN- and CrN-based transition-metal nitrides for thermoelectrics, and drawing parallels with piezoelectricity. We further discuss these materials as a models systems for general strategies for tailoring of thermoelectric properties by integrated theoretical-experimental approaches.

  14. Transition-metal-nitride-based thin films as novel energy harvesting materials

    PubMed Central

    Kerdsongpanya, Sit; Alling, Björn

    2016-01-01

    The last few years have seen a rise in the interest in early transition-metal and rare-earth nitrides, primarily based on ScN and CrN, for energy harvesting by thermoelectricity and piezoelectricity. This is because of a number of important advances, among those the discoveries of exceptionally high piezoelectric coupling coefficient in (Sc,Al)N alloys and of high thermoelectric power factors of ScN-based and CrN-based thin films. These materials also constitute well-defined model systems for investigating thermodynamics of mixing for alloying and nanostructural design for optimization of phase stability and band structure. These features have implications for and can be used for tailoring of thermoelectric and piezoelectric properties. In this highlight article, we review the ScN- and CrN-based transition-metal nitrides for thermoelectrics, and drawing parallels with piezoelectricity. We further discuss these materials as a models systems for general strategies for tailoring of thermoelectric properties by integrated theoretical–experimental approaches. PMID:27358737

  15. Effects on film structure on mechanical and adhesion properties of latex films

    SciTech Connect

    Charmeau, J.Y.; Holl, Y.; Kientz, E.

    1995-12-31

    In order to investigate the effect of the particular structure of latex films on mechanical (stress-strain behavior) and adhesion (measured by peeling) properties, this work compares these characteristics for latex films and corresponding {open_quotes}solution films{close_quotes}. Solution films were obtained by dissolving the latex film in an appropriate solvent and forming a new film by evaporating the solvent. Four different systems were studied. It was shown that latex films have Young`s moduli systematically much higher than the corresponding solution films. This is due to the fact that the hydrophilic shells of the latex particles form a continuous phase in the latex film which increases the modulus thanks to polar interactions. However, adhesion energy for latex films is always smaller than for solution films. This is interpreted in terms of structure of the film-support interface and dissipative processes within the bulk of the films.

  16. Obtaining and storage of ready-to-use segments from traditional orange obtained by enzymatic peeling.

    PubMed

    Sanchez-Bel, P; Egea, I; Serrano, M; Romojaro, A; Pretel, M T

    2012-02-01

    The aim of this study was to optimize all parameters implied in the process of obtaining orange segments as minimally processed product by enzymatic peeling, from the method of segment obtaining to the storage conditions, and also to evaluate two films with different permeability. Enzymatic peeling was carried out by fruit infusion under vacuum conditions in a commercial preparation of pectinases and cellulases (Peelzym II). The best condition to obtain Cadenera segments by enzymatic peeling was 1 mL/L of Peelzym II applied at 53 kPa with three vacuum pulses of 2 min and a subsequent period of 30 min in the enzymatic solution at atmospheric pressure. The segments were packaged in two films with different permeability and they were stored for 10 days at 4 °C. Samplings were carried out after 4, 7 and 10 days of storage. The results showed that the concentration of CO(2) in the less permeable film (PA 120) ranged between 0.7 and 1.2 mL/100 mL, while in the most permeable one (PA 240) was around 0.2 mL/100 mL. Under these conditions, the weight loss was kept at low levels until day 7 of storage, showing a significant increase after 10 days. Colour (a/b) increased with the peeling process and it remained without significant changes during the whole storage period for both films. The antioxidant capacity slightly decreased after 10 days of storage. The microbial flora was reduced after the enzymatic peeling. Both the sensory and the microbiological quality were kept in adequate levels for consumption during 7 days. From this moment, they lost sweetness and aroma and the microbial development increased. Thus, the use of the most permeable film and a maximum storage time of 7 days are recommended to maintain the most quality of the segments.

  17. Characterization of graphene oxide nanofilms obtained by the SAW atomization

    NASA Astrophysics Data System (ADS)

    Balachova, O. V.; Balashov, S. M.; Kubota, L. T.; Timm, R. A.; Nascimento, P. H.; Pavani Filho, A.; Moshkalev, S.

    2015-03-01

    Due to its ability to absorb water molecules, graphene oxide (GO) is considered a promising material for sensitive coatings in fast surface acoustic wave (SAW) humidity sensors. In this work, we characterize GO films obtained by the SAW atomization technique. It is shown that the atomized submicroliter droplets of aqueous suspension of GO can be deposited onto the surface of Si, LiNbO3 or quartz substrates forming discrete or continuous films of nanometer thickness. The deposited films were examined using AFM and electron microscopy. We discuss the dependence of thickness and structure of the obtained GO films on the parameters of deposition: the number of atomized droplets, a volume of the initial droplet, a distance between the atomizer and the sample, etc. To evaluate the adsorption characteristics of the obtained GO films, we used them as sensitive coatings of the SAW humidity sensors. We found that the adsorption characteristics of the GO films are determined by fast adsorption on the surface of GO sheets and slow adsorption, attributed to limited penetration of water molecules between the sheets, and depend on the number of deposited layers.

  18. Film Boxes.

    ERIC Educational Resources Information Center

    Osterer, Irv

    2002-01-01

    Presents an art lesson in which students created three-dimensional designs for 35mm film packages to improve graphic arts learning. Describes how the students examined and created film boxes using QuarkXPress software. (CMK)

  19. Film Boxes.

    ERIC Educational Resources Information Center

    Osterer, Irv

    2002-01-01

    Presents an art lesson in which students created three-dimensional designs for 35mm film packages to improve graphic arts learning. Describes how the students examined and created film boxes using QuarkXPress software. (CMK)

  20. Film Reviews

    ERIC Educational Resources Information Center

    Dowling, John, Ed.

    1976-01-01

    Reviews five instructional films on: P-N junctions; crystal diodes; nuclear fusion research; Schlieren photography; and the energy crisis; including discussions of solar, nuclear, and fossil fuel energy. Also lists numerous other available films. (MLH)

  1. Film Reviews

    ERIC Educational Resources Information Center

    Dowling, John, Ed.

    1976-01-01

    Reviews five instructional films on: P-N junctions; crystal diodes; nuclear fusion research; Schlieren photography; and the energy crisis; including discussions of solar, nuclear, and fossil fuel energy. Also lists numerous other available films. (MLH)

  2. Humanistic Films.

    ERIC Educational Resources Information Center

    Gaffney, Maureen, Ed.

    1981-01-01

    Designed for media specialists and educators, this issue includes seven articles focusing on humanistic films for children. Following a brief editorial encouraging the ideals of humanism, the first article presents an analysis of seven films with positive sex-role models. Included is a model for evaluating children's films. The second article…

  3. On Film

    ERIC Educational Resources Information Center

    Watts, Marty

    2006-01-01

    In this article, the author discusses the role of window films in enhancing indoor air quality in schools. Historically, window film has been used to reduce temperatures in buildings prone to overheating. Too much solar energy entering through windows makes occupants uncomfortable and air conditioning more costly. Film has been a simple solution…

  4. On Film

    ERIC Educational Resources Information Center

    Watts, Marty

    2006-01-01

    In this article, the author discusses the role of window films in enhancing indoor air quality in schools. Historically, window film has been used to reduce temperatures in buildings prone to overheating. Too much solar energy entering through windows makes occupants uncomfortable and air conditioning more costly. Film has been a simple solution…

  5. Nanocomposite films

    DOEpatents

    Mitlin, David; , Ophus, Colin; Evoy, Stephane; Radmilovic, Velimir; Mohammadi, Reza; Westra, Ken; Nelson-Fitzpatrick, Nathaniel; Lee, Zonghoon

    2010-07-20

    A thin-film composition of nanocrystal molybdenum in an amorphous metallic matrix may be formed by co-sputtering Mo with aluminum or nickel. NEMS cantilevers may be formed from the film. The films exhibit high nanoindentation hardness and a reduction in roughness and intrinsic stress, while maintaining resistivity in the metallic range.

  6. Effects of annealing electrodeposited bismuth Telluride films

    NASA Technical Reports Server (NTRS)

    Snyder, J.; Stoltz, N. G.

    2002-01-01

    Thermoelectric thin films exhibit different qualities when compared with bulk materials. The goal however is to achieve thermoelectric properties of bulk materials from electrodeposited thin films. Thin films are produced by electrochemical deposition at room temperature. In order to optimize thermoelectric figure of merit proper carrierconcentration must be obtained.

  7. The impact of multilayer periodicity on texture, morphology, chemical stability and machining performance of titanium aluminum nitride/chromium nitride thin films

    NASA Astrophysics Data System (ADS)

    Delisle, Dale Andrew

    Multilayer thin films of TiAlN/CrN were deposited at varying bilayer periods (λ = 2, 4, 8 and 16 nm), along with a co-deposited (TiAlCr)N film and constituent TiAlN and CrN films, on both [111] silicon substrates and WC-4wt% Co inserts with an ISO SPGN 120308 geometry. The effects of periodicity on grain structure, texture, surface morphology, and roughness were examined, with characterization performed using electron microscopy, atomic force microscopy and x-ray diffraction analysis. An in-air constant temperature oxidation study was also performed at 650 thru 1050°C with stacked XRD line profiles and SEM used to identify the onset and extent of oxidation, respectively. Finally, dry high speed flank wear tool life experiments were completed against A2 tool steel, with the impact of the multilayer period reported in ISO standard wear vs. cutting time format. Machining results were connected back to the previously identified changes in structure. All films exhibited a rocksalt B1-type structure with a columnar morphology and lateral coarsening during film growth; which was more pronounced in the multilayer films with smaller bilayer periods. The surface morphology was found to be dependent on period; exhibiting sharp pyramidal surface features at λ = 2 nm and an increase in secondary faceting with increasing periodicity. Nearly rounded column tops result at λ = 16 nm. Surface roughness measurements showed an increasing roughness with decreasing bilayer period and pole figures revealed a small [111] texture component perpendicular to the sample surface in the 2 and 4 nm period films, with the distribution of [111] poles becoming nearly random for the films with larger periodicities (8 and 16 nm). Preferential [200] poles begin approximately 15° tilted away from the substrate normal while further increase in period results in a decrease in the off axis angle. The effect of multilayer period on the surface morphology is explained using an energetic argument

  8. Synthesis of Diamond Films with Pulsed Plasmas.

    DTIC Science & Technology

    1991-08-01

    can be used also reduces the amount of reactants that can be dissociated which may adversely effect the film’s growth rate as well as quality. The use...not specifically address the optimization of temperature, to determine if a temperature effect did exist with pulsed-plasma depositions, the... effect the growth rate and quality of the diamond film. Baseline films obtained with CW formed plasmas had growth rates and film quality that exceeded any

  9. Paradoxes in Film Ratings

    ERIC Educational Resources Information Center

    Moore, Thomas L.

    2006-01-01

    The author selected a simple random sample of 100 movies from the "Movie and Video Guide" (1996), by Leonard Maltin. The author's intent was to obtain some basic information on the population of roughly 19,000 movies through a small sample. The "Movie and Video Guide" by Leonard Maltin is an annual ratings guide to movies. While not all films ever…

  10. Paradoxes in Film Ratings

    ERIC Educational Resources Information Center

    Moore, Thomas L.

    2006-01-01

    The author selected a simple random sample of 100 movies from the "Movie and Video Guide" (1996), by Leonard Maltin. The author's intent was to obtain some basic information on the population of roughly 19,000 movies through a small sample. The "Movie and Video Guide" by Leonard Maltin is an annual ratings guide to movies. While not all films ever…

  11. Film ispalators

    SciTech Connect

    Startsev, Aleksandr V; Stoilov, Yurii Yu

    2002-05-31

    New physical objects, ispalators based on free soap films, exhibit persistent flows of the soap solution in open and closed volumes in air with additions of gases of the C{sub 8}F{sub 18} type (p = 20 Torr) at temperature drops on the films of the order of tenths and hundredths of kelvin. The flows move continuously at a velocity of 5 - 20 cm s{sup -1}. It is found that the parts of an inclined ispalator film show anomalous behaviour upon heating: their weight increases and they move downward over the film, whereas the unheated parts of the film move upward. Continuous radial vortex flows accompanied by the formation and washing of the regions of a thin black film are observed on circular films in closed volumes upon their uniform external cooling by evaporating water for 5 - 10 hours. The rapid flows make film ispalators the efficient heat carriers, which operate at small temperature drops (tenths and hundredths of kelvin) and surpass copper in the amount of thermal energy being transferred. The outlook for the further study and applications of film ispalators for detecting thermal fields and laser radiation is discussed. (laser applications and other topics in quantum electronics)

  12. 21 CFR 892.1670 - Spot-film device.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy....

  13. 21 CFR 892.1670 - Spot-film device.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy....

  14. 21 CFR 892.1670 - Spot-film device.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy....

  15. 21 CFR 892.1670 - Spot-film device.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy....

  16. 21 CFR 892.1670 - Spot-film device.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Spot-film device. 892.1670 Section 892.1670 Food... DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1670 Spot-film device. (a) Identification. A spot-film... medical purposes to position a radiographic film cassette to obtain radiographs during fluoroscopy....

  17. Film Language.

    ERIC Educational Resources Information Center

    Hudlin, Edward W.

    1979-01-01

    The author briefly surveys some of the claims made about the presumed nature of film as language and some of the problems that arise. He considers the views of two influential schools of film criticism: the Russian formalists (Pudovkin and Eisenstein) and the British semiologist (Peter Wollen). (Author/SJL)

  18. Thin Film?

    NASA Astrophysics Data System (ADS)

    Kariper, İ. Afşin

    2014-09-01

    This study focuses on the critical surface tension of lead sulfite (PbSO3) crystalline thin film produced with chemical bath deposition on substrates (commercial glass).The PbSO3 thin films were deposited at room temperature at different deposition times. The structural properties of the films were defined and examined according to X-ray diffraction (XRD) and the XRD results such as dislocation density, average grain size, and no. of crystallites per unit area. Atomic force microscopy was used to measure the film thickness and the surface properties. The critical surface tension of the PbSO3 thin films was measured with an optical tensiometer instrument and calculated using the Zisman method. The results indicated that the critical surface tension of films changed in accordance with the average grain size and film thickness. The film thickness increased with deposition time and was inversely correlated with surface tension. The average grain size increased according to deposition time and was inversely correlated with surface tension.

  19. About Films.

    ERIC Educational Resources Information Center

    Christman, Robert; Krockover, Gerald H.

    1984-01-01

    Lists and briefly describes 46 college-level films. Films are arranged in the following categories: volcanism and earthquakes; plate tectonics; energy, water, and environmental concerns; petroleum and coal; astronomy; space exploration, space shuttle; paleontology; geomorphology; and mineralogy, petrology, and economic geology. (BC)

  20. About Films.

    ERIC Educational Resources Information Center

    Christman, Robert; Krockover, Gerald H.

    1984-01-01

    Lists and briefly describes 46 college-level films. Films are arranged in the following categories: volcanism and earthquakes; plate tectonics; energy, water, and environmental concerns; petroleum and coal; astronomy; space exploration, space shuttle; paleontology; geomorphology; and mineralogy, petrology, and economic geology. (BC)

  1. Biomimetic thin film deposition

    NASA Astrophysics Data System (ADS)

    Rieke, P. C.; Campbell, A. A.; Tarasevich, B. J.; Fryxell, G. E.; Bentjen, S. B.

    1991-04-01

    Surfaces derivatized with organic functional groups were used to promote the deposition of thin films of inorganic minerals. These derivatized surfaces were designed to mimic the nucleation proteins that control mineral deposition during formation of bone, shell, and other hard tissues in living organisms. By the use of derivatized substrates control was obtained over the phase of mineral deposited, the orientation of the crystal lattice and the location of deposition. These features are of considerable importance in many technically important thin films, coatings, and composite materials. Methods of derivatizing surfaces are considered and examples of controlled mineral deposition are presented.

  2. Drying of thin colloidal films

    NASA Astrophysics Data System (ADS)

    Routh, Alexander F.

    2013-04-01

    When thin films of colloidal fluids are dried, a range of transitions are observed and the final film profile is found to depend on the processes that occur during the drying step. This article describes the drying process, initially concentrating on the various transitions. Particles are seen to initially consolidate at the edge of a drying droplet, the so-called coffee-ring effect. Flow is seen to be from the centre of the drop towards the edge and a front of close-packed particles passes horizontally across the film. Just behind the particle front the now solid film often displays cracks and finally the film is observed to de-wet. These various transitions are explained, with particular reference to the capillary pressure which forms in the solidified region of the film. The reasons for cracking in thin films is explored as well as various methods to minimize its effect. Methods to obtain stratified coatings through a single application are considered for a one-dimensional drying problem and this is then extended to two-dimensional films. Different evaporative models are described, including the physical reason for enhanced evaporation at the edge of droplets. The various scenarios when evaporation is found to be uniform across a drying film are then explained. Finally different experimental techniques for examining the drying step are mentioned and the article ends with suggested areas that warrant further study.

  3. Film Makers On Film Making.

    ERIC Educational Resources Information Center

    Geduld, Harry M., Ed.

    This collection includes essays by and interviews with more than 30 film-makers, both classic and contemporary, on the subjects of their major interests and procedures in making films. The directors are: Louis Lumiere, Cecil Hepworth, Edwin S. Porter, Mack Sennett, David W. Griffith, Robert Flaherty, Charles Chaplin, Eric von Stroheim, Dziga…

  4. Film Makers On Film Making.

    ERIC Educational Resources Information Center

    Geduld, Harry M., Ed.

    This collection includes essays by and interviews with more than 30 film-makers, both classic and contemporary, on the subjects of their major interests and procedures in making films. The directors are: Louis Lumiere, Cecil Hepworth, Edwin S. Porter, Mack Sennett, David W. Griffith, Robert Flaherty, Charles Chaplin, Eric von Stroheim, Dziga…

  5. Obtaining Public Records: Reporter Guide

    ERIC Educational Resources Information Center

    Hammond, Betsy

    2013-01-01

    Obtaining public records is essential to covering public education. Fortunately, the law is on the side of reporters: Public agencies generally must disclose their records to the public and to the media--with important exceptions. Public agencies are often reluctant to hand over records, however, even when the law clearly says they should.…

  6. Employment Obtaining and Business Starting

    ERIC Educational Resources Information Center

    Lan, Jian

    2009-01-01

    The implementation of business starting education in higher vocational colleges is of important and realistic meanings for cultivating advanced technology application-type talents and for releasing the employment obtaining pressure of higher vocational students. Based on the analysis on the employment situation of higher vocational graduates, this…

  7. Permeation of volatile compounds through starch films.

    PubMed

    Yilmaz, Gülden; Jongboom, Remy O J; Feil, Herman; van Dijk, Cees; Hennink, Wim E

    2004-01-01

    The aim of this study was to gain insight into the factors that affect the permeation of volatiles through starch films. These films were obtained by casting gelatinized starch/water/glycerol mixtures. The films were dried and conditioned under different conditions (temperature and relative humidity) resulting in films that vary in the degree of starch crystallinity and glycerol and water content. The permeation of two model volatiles (carvone and diacetyl) at 20 degrees C and at 30, 60, or 90% relative humidity (RH) was analyzed gravimetrically. Further, the solubility of the two model compounds (under conditions where the permeation experiments were carried out) was determined. From the obtained permeation and solubility data, the diffusion coefficients of these compounds in the different starch films were calculated. The crystallinity in the starch films increased with increasing water content of the films during preparation. The water content of the resulting films in turn increased with increasing glycerol and when the films were exposed to a higher RH during drying or conditioning. For films with the same composition, the flux for diacetyl was greater than for carvone. The solubilities of diacetyl and carvone were slightly dependent on the properties of the films. It was found that with increasing starch crystallinity the diffusion coefficient for both compounds decreases, which is probably due to the impermeability of starch crystallites. Interestingly, in films with about the same extent of crystallinity, the diffusion can be described with the free volume model, with water and glycerol determining the amount of free volume.

  8. Films for eliciting emotional states in children.

    PubMed

    von Leupoldt, Andreas; Rohde, Jenny; Beregova, Anna; Thordsen-Sörensen, Imke; zur Nieden, Janine; Dahme, Bernhard

    2007-08-01

    Standardized sets of films have been shown to be effective for eliciting emotional states in adults, but no comparable validated stimuli are available for children. We therefore examined the effects of three pre-selected film clips each of 3-min duration in eliciting a pleasant, neutral and unpleasant emotional state in 297 children aged between 6 and 12 years. After the films were presented on a video projector, affective ratings were obtained with the Self-Assessment-Manikin on the emotional dimensions of valence and arousal. Increasing pleasure ratings were observed from the unpleasant to the neutral to the pleasant film. Associated arousal ratings were stronger for the unpleasant and pleasant films compared to the neutral film. Overall, results showed successful elicitation of targeted emotional states only marginally influenced by age, gender or prior experience with the films. The use of these films is therefore suggested for future studies on emotions in children.

  9. Obtaining consent for eye donation.

    PubMed

    Diamond, G A; Campion, M; Mussoline, J F; D'Amico, R A

    1987-02-15

    We prospectively studied 100 consecutive deaths at St. Vincent's Hospital and Medical Center in New York City for possible eye donation. Fifty-two patients were unsuitable mainly because of medical contraindications and age at death. Of the 48 suitable candidates, 21 pairs (44%) of eyes were obtained. Sixteen of the 42 eyes (38%) were used for transplantation. Projection of the number of corneas obtainable for transplant in New York City were calculated. The figures indicated that the three-month waiting list of the New York Eye-Bank for Sight Restoration, Inc., could be eradicated if hospitals were able to get seven donors from every 100 deaths suitable for donation, a rate only 16% of that realized in this study.

  10. Novel tribological systems using shape memory alloys and thin films

    NASA Astrophysics Data System (ADS)

    Zhang, Yijun

    Shape memory alloys and thin films are shown to have robust indentation-induced shape memory and superelastic effects. Loading conditions that are similar to indentations are very common in tribological systems. Therefore novel tribological systems that have better wear resistance and stronger coating to substrate adhesion can be engineered using indentation-induced shape memory and superelastic effects. By incorporating superelastic NiTi thin films as interlayers between chromium nitride (CrN) and diamond-like carbon (DLC) hard coatings and aluminum substrates, it is shown that the superelasticity can improve tribological performance and increase interfacial adhesion. The NiTi interlayers were sputter deposited onto 6061 T6 aluminum and M2 steel substrates. CrN and DLC coatings were deposited by unbalanced magnetron sputter deposition. Temperature scanning X-ray diffraction and nanoindentation were used to characterize NiTi interlayers. Temperature scanning wear and scratch tests showed that superelastic NiTi interlayers improved tribological performance on aluminum substrates significantly. The two-way shape memory effect under contact loading conditions is demonstrated for the first time, which could be used to make novel tribological systems. Spherical indents in NiTi shape memory alloys and thin films had reversible depth changes that were driven by temperature cycling, after thermomechanical cycling, or one-cycle slip-plasticity deformation training. Reversible surface topography was realized after the indents were planarized. Micro- and nano- scale circular surface protrusions arose from planarized spherical indents in bulk and thin film NiTi alloy; line surface protrusions appeared from planarized scratch tracks. Functional surfaces with reversible surface topography can potentially result in novel tribological systems with reversible friction coefficient. A three dimensional constitutive model was developed to describe shape memory effects with slip

  11. Annealing and structural properties of composite films

    NASA Astrophysics Data System (ADS)

    Kotov, L. N.; Ustyugov, V. A.; Vlasov, V. S.; Turkov, V. K.; Dianov, M. Yu; Antonets, I. V.; Kalinin, Yu E.; Sitnikov, A. V.; Golubev, E. A.

    2017-02-01

    The composite films were investigated by AFM methods before and after annealing. Topographic and phase-contrast AFM images of the composite films at different annealing temperature were obtained. The separate metal granules and larger-scale labyrinth-like formations were described. These formations appear by the process of the film growth, also by film annealing. Strong changes of the structural properties of the films are observed after the percolation transition. The significant changes of the structural properties are connected with nanostructural transformations in the metal granules topology and presence of metal crystal phase.

  12. Polymer films

    DOEpatents

    Granick, Steve; Sukhishvili, Svetlana A.

    2008-12-30

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  13. Polymer films

    DOEpatents

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  14. Film Reviews

    ERIC Educational Resources Information Center

    Ladd, George T.

    1974-01-01

    Briefly describes films about the following topics: water cycles, the energy crisis, the eruption of Mt. Aetna, the hot springs of Yellowstone National Park, and methods of using pine cones to determine the ages of ancient civilizations. (MLH)

  15. Piezoelectric Film.

    ERIC Educational Resources Information Center

    Garrison, Steve

    1992-01-01

    Presents activities that utilize piezoelectric film to familiarize students with fundamental principles of electricity. Describes classroom projects involving chemical sensors, microbalances, microphones, switches, infrared sensors, and power generation. (MDH)

  16. Piezoelectric Film.

    ERIC Educational Resources Information Center

    Garrison, Steve

    1992-01-01

    Presents activities that utilize piezoelectric film to familiarize students with fundamental principles of electricity. Describes classroom projects involving chemical sensors, microbalances, microphones, switches, infrared sensors, and power generation. (MDH)

  17. Film Reviews

    ERIC Educational Resources Information Center

    Ladd, George T.

    1974-01-01

    Briefly describes films about the following topics: water cycles, the energy crisis, the eruption of Mt. Aetna, the hot springs of Yellowstone National Park, and methods of using pine cones to determine the ages of ancient civilizations. (MLH)

  18. Spinodal dewetting of thin films

    NASA Astrophysics Data System (ADS)

    Jaiswal, Prabhat K.; Puri, S.

    2009-01-01

    Stable thin liquid films are of various scientific and technological applications, e.g., in optical coating, painting technologies, coating thin wires and fibers, lubricants, adhesives, etc. However, the instabilities in a thin film may lead to rupture, hole formation, and other morphological changes which amplify the nonuniformity in the thin film [1]. This morphological evolution in an unstable thin film is generally known as `dewetting' [2]. There have recently been a number of theoretical and experimental studies on dewetting in thin films [3-6]. The process of `spinodal dewetting' comes into the category of a general class of phenomena, spinodal decomposition [7]. The pattern formation taking place during dewetting can also be of great importance in nanotechnology, e.g., for preparing quantum dots [8], nanorings [9], etc. We numerically solve the nonlinear two-dimensional thin film equation [2] for a thin liquid film subjected to the long range van der Waals attraction and short range Born repulsion. The simulation results for the temporal evolution of domains and height profile along diagonal direction of the lattice show the `hills and valleys' short of structures which is the typical morphology obtained during the spinodal dewetting [10]. We obtain the dynamical correlation function and structure factor showing the existence of a characteristic length scale in the system at late time. We give the scaling arguments for the length scale of the drops to be proportional to t1/3 which is in agreement with our numerical results for the domain growth.

  19. Vortex images in thin films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} and Bi{sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub 8+{ital x}} obtained by low-temperature magnetic force microscopy

    SciTech Connect

    Yuan, C.W.; Zheng, Z.; de Lozanne, A.L.; Tortonese, M.; Rudman, D.A.; Eckstein, J.N.

    1996-03-01

    We have imaged vortices in superconducting thin films with a low-temperature magnetic force microscope that utilizes microfabricated piezoresistive cantilevers with built-in tips. The films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} and Bi{sub 2}Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub 8+{ital x}}, are made by laser ablation and molecular beam epitaxy, respectively. The vortices usually appear as round features in the noncontact image with a diameter of about 1 {mu}m or slightly less. In some cases the position of the vortices is correlated to defects observed in the topographic image of the same area. The vortices move sometimes, especially after taking a topographic (contact mode) scan.

  20. Single-layer nano-carbon film, diamond film, and diamond/nano-carbon composite film field emission performance comparison

    SciTech Connect

    Wang, Xiaoping E-mail: wxpchina@sohu.com; Wang, Jinye; Wang, Lijun

    2016-05-09

    A series of single-layer nano-carbon (SNC) films, diamond films, and diamond/nano-carbon (D/NC) composite films have been prepared on the highly doped silicon substrate by using microwave plasma chemical vapor deposition techniques. The films were characterised by scanning electron microscopy, Raman spectroscopy, and field emission I-V measurements. The experimental results indicated that the field emission maximum current density of D/NC composite films is 11.8–17.8 times that of diamond films. And the field emission current density of D/NC composite films is 2.9–5 times that of SNC films at an electric field of 3.0 V/μm. At the same time, the D/NC composite film exhibits the advantage of improved reproducibility and long term stability (both of the nano-carbon film within the D/NC composite cathode and the SNC cathode were prepared under the same experimental conditions). And for the D/NC composite sample, a high current density of 10 mA/cm{sup 2} at an electric field of 3.0 V/μm was obtained. Diamond layer can effectively improve the field emission characteristics of nano-carbon film. The reason may be due to the diamond film acts as the electron acceleration layer.

  1. Single-layer nano-carbon film, diamond film, and diamond/nano-carbon composite film field emission performance comparison

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoping; Wang, Jinye; Wang, Lijun

    2016-05-01

    A series of single-layer nano-carbon (SNC) films, diamond films, and diamond/nano-carbon (D/NC) composite films have been prepared on the highly doped silicon substrate by using microwave plasma chemical vapor deposition techniques. The films were characterised by scanning electron microscopy, Raman spectroscopy, and field emission I-V measurements. The experimental results indicated that the field emission maximum current density of D/NC composite films is 11.8-17.8 times that of diamond films. And the field emission current density of D/NC composite films is 2.9-5 times that of SNC films at an electric field of 3.0 V/μm. At the same time, the D/NC composite film exhibits the advantage of improved reproducibility and long term stability (both of the nano-carbon film within the D/NC composite cathode and the SNC cathode were prepared under the same experimental conditions). And for the D/NC composite sample, a high current density of 10 mA/cm2 at an electric field of 3.0 V/μm was obtained. Diamond layer can effectively improve the field emission characteristics of nano-carbon film. The reason may be due to the diamond film acts as the electron acceleration layer.

  2. How To Obtain Aerial Photographs

    USGS Publications Warehouse

    ,

    1999-01-01

    The U.S. Geological Survey (USGS) maintains an informational data base of aerial photographic coverage of the United States and its territories that dates back to the 1940?s. This information describes photographic projects from the USGS, other Federal, State, and local government agencies, and commercial firms. The pictures on this page show a part of a standard 9- by 9-inch photograph and the results obtained by enlarging the original photograph two and four times. Compare the size of the Qualcomm Stadium, Jack Murphy Field, in San Diego, Calif, and the adjacent parking lot and freeways shown at the different scales. USGS Earth Science Information Center (ESIC) representatives will assist you in locating and ordering photographs. Please submit the completed checklist and a marked map showing your area of interest to any ESIC.

  3. Structural and optical properties of Tin sulphide thin films

    SciTech Connect

    Akkari, A.; Ben Nasr, T.; Kamoun, N.

    2007-09-19

    Tin sulphide SnS thin films were deposited on glass substrates using the chemical bath deposition technique (CBD). By investigating the influence of triethanolamine (TEA) concentration on the properties of deposited films, we obtained the optimum deposition parameter. These films were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) analysis and spectrophotometric measurements. The obtained thin films exhibit the orthorhombic structure and the direct band gap energy is found to be about 1.65 eV, for films prepared at TEA concentration films equal to 13.5 M.

  4. Shortened procedure for obtaining reproducible copies of 35 mm color slides

    NASA Technical Reports Server (NTRS)

    Levine, F.

    1968-01-01

    Technique to reduce the steps required to obtain reproducible copies of 35 mm color slides has been developed. A 35 mm slide is projected directly onto a Xerox plate, eliminating the necessity to produce a film positive of the slide.

  5. Science Fiction on Film.

    ERIC Educational Resources Information Center

    Burmester, David

    1985-01-01

    Reviews science fiction films used in a science fiction class. Discusses feature films, short science fiction films, short story adaptations, original science fiction pieces and factual science films that enrich literature. (EL)

  6. Science Fiction on Film.

    ERIC Educational Resources Information Center

    Burmester, David

    1985-01-01

    Reviews science fiction films used in a science fiction class. Discusses feature films, short science fiction films, short story adaptations, original science fiction pieces and factual science films that enrich literature. (EL)

  7. Diamond ultraviolet photovoltaic cell obtained by lithium and boron doping

    SciTech Connect

    Popovici, G.; Melnikov, A.; Varichenko, V.V.; Sung, T.; Prelas, M.A.; Wilson, R.G.; Loyalka, S.K.

    1997-03-01

    Polycrystalline high quality freestanding 300-{mu}m-thick diamond films were doped by diffusion of B and Li under electric bias in order to fabricate vertical p-n junctions. Circular contacts were obtained by high dose ion implantation of B and Li. The I{endash}V characteristics were rectifying. When illuminated by deuterium lamp, an open circuit voltage was 2.6 eV. The shape of the I{endash}V characteristic under illumination points to the existence of shunt and series resistances. The obtained structure is most probably a p-n junction with bad contacts. {copyright} {ital 1997 American Institute of Physics.}

  8. Field Emission and Nanostructure of Carbon Films

    SciTech Connect

    Merkulov, V.I.; Lowndes, D.H.; Baylor, L.R.

    1999-11-29

    The results of field emission measurements of various forms of carbon films are reported. It is shown that the films nanostructure is a crucial factor determining the field emission properties. In particular, smooth, pulsed-laser deposited amorphous carbon films with both high and low sp3 contents are poor field emitters. This is similar to the results obtained for smooth nanocrystalline, sp2-bonded carbon films. In contrast, carbon films prepared by hot-filament chemical vapor deposition (HE-CVD) exhibit very good field emission properties, including low emission turn-on fields, high emission site density, and excellent durability. HF-CVD carbon films were found to be predominantly sp2-bonded. However, surface morphology studies show that these films are thoroughly nanostructured, which is believed to be responsible for their promising field emission properties.

  9. Infrared radiation of thin plastic films.

    NASA Technical Reports Server (NTRS)

    Tien, C. L.; Chan, C. K.; Cunnington, G. R.

    1972-01-01

    A combined analytical and experimental study is presented for infrared radiation characteristics of thin plastic films with and without a metal substrate. On the basis of the thin-film analysis, a simple analytical technique is developed for determining band-averaged optical constants of thin plastic films from spectral normal transmittance data for two different film thicknesses. Specifically, the band-averaged optical constants of polyethylene terephthalate and polyimide were obtained from transmittance measurements of films with thicknesses in the range of 0.25 to 3 mil. The spectral normal reflectance and total normal emittance of the film side of singly aluminized films are calculated by use of optical constants; the results compare favorably with measured values.

  10. Infrared radiation of thin plastic films.

    NASA Technical Reports Server (NTRS)

    Tien, C. L.; Chan, C. K.; Cunnington, G. R.

    1972-01-01

    A combined analytical and experimental study is presented for infrared radiation characteristics of thin plastic films with and without a metal substrate. On the basis of the thin-film analysis, a simple analytical technique is developed for determining band-averaged optical constants of thin plastic films from spectral normal transmittance data for two different film thicknesses. Specifically, the band-averaged optical constants of polyethylene terephthalate and polyimide were obtained from transmittance measurements of films with thicknesses in the range of 0.25 to 3 mil. The spectral normal reflectance and total normal emittance of the film side of singly aluminized films are calculated by use of optical constants; the results compare favorably with measured values.

  11. Jet impact on a soap film.

    PubMed

    Kirstetter, Geoffroy; Raufaste, Christophe; Celestini, Franck

    2012-09-01

    We experimentally investigate the impact of a liquid jet on a soap film. We observe that the jet never breaks the film and that two qualitatively different steady regimes may occur. The first one is a refractionlike behavior obtained at small incidence angles when the jet crosses the film and is deflected by the film-jet interaction. For larger incidence angles, the jet is absorbed by the film, giving rise to a new class of flows in which the jet undulates along the film with a characteristic wavelength. Besides its fundamental interest, this paper presents a different way to guide a micrometric flow of liquid in the inertial regime and to probe foam stability submitted to violent perturbations at the soap film scale.

  12. Feasibility demonstration for electroplating ultra-thin polyimide film. [fabricating film for space erectable structures

    NASA Technical Reports Server (NTRS)

    Schneier, R.; Braswell, T. V.; Vaughn, R. W.

    1978-01-01

    The effect of electrodeposition variables on film thickness was investigated using a dilute polyimide solution as a bath into which aluminum (as foil or as a vapor deposited coating) was immersed. The electrodeposited film was dried for 2 hours at 93 C (primarily to remove solvent) and cured for 18 hours at 186 C. Infrared studies indicate that imide formation (curing) occurs at 149 C under vacuum. From a conceptual viewpoint, satisfactory film metallized on one side can be obtained by this method. The cured ultra thin polyimide film exhibits properties equivalent to those of commercial film, and the surface appearance of the strippable polyimide film compares favorably with that of a sample of commercial film of thicker gauge. The feasibility of manufacturing approximately one million sq m of ultra thin film capable of being joined to fabricate an 800 m by 9 800 m square from starting material 0.5 to 1 m wide for space erectable structures was demonstrated.

  13. Fluorescent Bioactive Corrole Grafted-Chitosan Films.

    PubMed

    Barata, Joana F B; Pinto, Ricardo J B; Vaz Serra, Vanda I R C; Silvestre, Armando J D; Trindade, Tito; Neves, Maria Graça P M S; Cavaleiro, José A S; Daina, Sara; Sadocco, Patrizia; Freire, Carmen S R

    2016-04-11

    Transparent corrole grafted-chitosan films were prepared by chemical modification of chitosan with a corrole macrocycle, namely, 5,10,15-tris(pentafluorophenyl)corrole (TPFC), followed by solvent casting. The obtained films were characterized in terms of absorption spectra (UV-vis), FLIM (fluorescence lifetime imaging microscopy), structure (FTIR, XPS), thermal stability (TGA), thermomechanical properties (DMA), and antibacterial activity. The results showed that the chemical grafting of chitosan with corrole units did not affect its film-forming ability and that the grafting yield increased with the reaction time. The obtained transparent films presented fluorescence which increases with the amount of grafted corrole units. Additionally, all films showed bacteriostatic effect against S. aureus, as well as good thermomechanical properties and thermal stability. Considering these features, promising applications may be envisaged for these corrole-chitosan films, such as biosensors, bioimaging agents, and bioactive optical devices.

  14. Turbine airfoil film cooling

    NASA Technical Reports Server (NTRS)

    Hylton, Larry D.

    1986-01-01

    Emphasis is placed on developing more accurate analytical models for predicting turbine airfoil external heat transfer rates. Performance goals of new engines require highly refined, accurate design tools to meet durability requirements. In order to obtain improvements in analytical capabilities, programs are required which focus on enhancing analytical techniques through verification of new models by comparison with relevant experimental data. The objectives of the current program are to develop an analytical approach, based on boundary layer theory, for predicting the effects of airfoil film cooling on downstream heat transfer rates and to verify the resulting analytical method by comparison of predictions with hot cascade data obtained under this program.

  15. Light scattering by porous oriented polypropylene films

    NASA Astrophysics Data System (ADS)

    Zinchik, A. A.; Kuryndin, I. S.; Elyashevich, G. K.

    2017-03-01

    Oriented porous polypropylene films with lamellar crystal structure are studied by the laser radiation scattering method. The dependence of the scattering pattern on the degree of film orientation is determined. It is shown that the sizes of the central maximum of the scattering pattern depend linearly on the degree of film extension. The results obtained can be used in developing methods of optical nondestructive testing of polymeric materials.

  16. Structure and Morphology of Phthalocyanine Films Grown in Electrical Fields by Vapor Deposition

    NASA Technical Reports Server (NTRS)

    Zhu, Shen; Banks, C. E.; Frazier, D. O.; Penn, B.; Abdeldayem, H.; Hicks, R.; Burns, H. D.; Thompson, G. W.

    1999-01-01

    Phthalocyanine (Pc) films have been synthesized by vapor deposition on quartz substrates, some of which were coated with a very thin gold film before depositing Pc films. Electrical fields up to 6200 V/cm between a mech electrode and the substrate are introduced during film growth. These films have been characterized by x-ray diffraction and scanning electron microscopy. The molecular orientations and surface morphology of Pc films were changed under the electrical fields. The surface of these films grown without electrical field shows whisk-like morphology. When films are deposited under an electrical field, a dense film with flat surface is obtained.

  17. Film Credits

    ERIC Educational Resources Information Center

    Borja, Rhea R.

    2006-01-01

    With the advent of easy-to-use digital technology, schools are responding to the interests of their media-savvy students by offering more courses in filmmaking. In this article, the author features different films produced by students. Among other things, she discusses the students' growing interest in filmmaking.

  18. Film Credits

    ERIC Educational Resources Information Center

    Borja, Rhea R.

    2006-01-01

    With the advent of easy-to-use digital technology, schools are responding to the interests of their media-savvy students by offering more courses in filmmaking. In this article, the author features different films produced by students. Among other things, she discusses the students' growing interest in filmmaking.

  19. Thin Films

    NASA Astrophysics Data System (ADS)

    Naffouti, Wafa; Nasr, Tarek Ben; Mehdi, Ahmed; Kamoun-Turki, Najoua

    2014-11-01

    Titanium dioxide (TiO2) thin films were synthesized on glass substrates by spray pyrolysis. The effect of solution flow rate on the physical properties of the films was investigated by use of x-ray diffraction (XRD), scanning electron microscopy, atomic force microscopy (AFM), and spectrophotometry techniques. XRD analysis revealed the tetragonal anatase phase of TiO2 with highly preferred (101) orientation. AFM images showed that grain size on top of TiO2 thin films depended on solution flow rate. An indirect band gap energy of 3.46 eV was determined by means of transmission and reflection measurements. The envelope method, based on the optical transmission spectrum, was used to determine film thickness and optical constants, for example real and imaginary parts of the dielectric constant, refractive index, and extinction coefficient. Ultraviolet and visible photoluminescence emission peaks were observed at room temperature. These peaks were attributed to the intrinsic emission and to the surface defect states, respectively.

  20. Structural investigation of Cr(Al)N/SiOx films prepared on Si substrates by differential pumping cosputtering.

    PubMed

    Kawasaki, Masahiro; Takabatake, Hiroshi; Onishi, Ichiro; Nose, Masateru; Shiojiri, Makoto

    2013-05-01

    Analytical electron microscopy revealed the structure and growth of hard coating Cr(Al)N/SiOx nanocomposite films prepared in a differential pumping cosputtering (DPCS) system, which has two chambers to sputter different materials and a rotating substrate holder. The substrate holder was heated at 250 °C and rotated at a speed as low as 1 rpm. In order to promote the adhesion between the substrate and composite film, transition layers were deposited on a (001) Si substrate by sputtering from the CrAl target with an Ar flow and a mixture flow of Ar and N2 (Ar/N2) gases, subsequently, prior to the composite film deposition. Then, the Cr(Al)N/SiOx nanocomposite film was fabricated on the transition layers by cosputtering from the CrAl target with the Ar/N2 gas flow and from the SiO2 target with the Ar gas flow. The film had a multilayer structure of ∼1.6 nm thick crystallite layers of Cr(Al)N similar to NaCl-type CrN and ∼1 nm thick amorphous silicon oxide layers. The structure of the transition layers was also elucidated. These results can help with the fabrication of new hard nanocomposite films by DPCS.

  1. Oxidation of nano-multilayered AlTiSiN thin films between 600 and 1000 degrees C in air.

    PubMed

    Lee, Jae Chun; Kim, Sun Kyu; Nguyen, Thuan Dinh; Lee, Dong Bok

    2011-07-01

    Multilayered AlTiSiN films with a composition of 32.0Al-12.4Ti-4.9Si-50.7N (at.%) were deposited on a steel substrate in a nitrogen atmosphere by cathodic arc plasma deposition. The films consisted of crystalline approximately 8 nm-thick AISiN nanolayers that originated from the Al-Si target and approximately 3 nm-thick TiN nanolayers that originated from the Ti target. Their oxidation characteristics were studied between 600 and 1000 degrees C for up to 20 h in air. They displayed good oxidation resistance due to the formation of a thin, dense Al2O3 surface scale below which an (Al2O3, TiO2, SiO2)-intermixed inner scale existed. They oxidized slower than TiN films because protective Al2O3-rich scales formed on the surface. However, they oxidized faster than CrN films because impure Al2O3 scale formed on the AlTiSiN film. Their oxidation progressed primarily by the outward diffusion of nitrogen and substrate elements, combined with the inward transport of oxygen that gradually reacted with Al, Ti, and Si in the film.

  2. Superconducting Thin Films Composites and Junctions

    DTIC Science & Technology

    1988-10-31

    results so far have been obtained with atomic oxygen. Epitaxial films with high critical currents have been grown on SrTiO3 > and >, A1203ə 102...on substrates including (100) MgO and (100) SrTiO3 using pulsed laser ablation of a variety of targets. The films have been characterized using...externally added vapors of the 0-diketonate to obtain steady evaporative behavior. Superconducting films were obtained on SrTiO3 substrates at

  3. Obtaining self-similar scalings in focusing flows

    NASA Astrophysics Data System (ADS)

    Dijksman, Joshua; Mukhopadhyay, Shomeek; Gaebler, Cameron; Witelski, Thomas; Behringer, Robert

    The surface structure of converging thin fluid films displays self-similar behavior, as was shown in the work by Diez et al [Q. Appl. Math 210, 155, 1990]. Extracting the related similarity scaling exponents from either numerical or experimental data is non-trivial. Here we provide two such methods. We apply them to experimental and numerical data on converging fluid films driven by both surface tension and gravitational forcing. In the limit of pure gravitational driving, we recover Diez' semi-analytic result, but our methods also allow us to explore the entire regime of mixed capillary and gravitational driving, up to entirely surface tension driven flows. We find scaling forms of smoothly varying exponents up to surprisingly small Bond numbers. Our experimental results are in reasonable agreement with our numerical simulations, which confirm theoretically obtained relations between the scaling exponents.

  4. Obtaining self-similar scalings in focusing flows

    NASA Astrophysics Data System (ADS)

    Dijksman, Joshua A.; Mukhopadhyay, Shomeek; Gaebler, Cameron; Witelski, Thomas P.; Behringer, Robert P.

    2015-10-01

    The surface structure of converging thin fluid films displays self-similar behavior, as was shown in the work by Diez et al. [Q. Appl. Math. 210, 155 (1990)]. Extracting the related similarity scaling exponents from either numerical or experimental data is nontrivial. Here we provide two such methods. We apply them to experimental and numerical data on converging fluid films driven by both surface tension and gravitational forcing. In the limit of pure gravitational driving, we recover Diez' semianalytic result, but our methods also allow us to explore the entire regime of mixed capillary and gravitational driving, up to entirely surface-tension-driven flows. We find scaling forms of smoothly varying exponents up to surprisingly small Bond numbers. Our experimental results are in reasonable agreement with our numerical simulations, which confirm theoretically obtained relations between the scaling exponents.

  5. Black Films and Film-Makers.

    ERIC Educational Resources Information Center

    Patterson, Lindsay, Ed.

    The development of black films and the attitudes of the film industry toward black films and black actors are some of the topics examined in this anthology of essays. Section 1, "Nigger to Supernigger," contains such articles as "The Death of Rastus: Negroes in American Films" by Thomas R. Cripps and "Folk Values in a New Medium" by Alain Locke…

  6. Black Films and Film-Makers.

    ERIC Educational Resources Information Center

    Patterson, Lindsay, Ed.

    The development of black films and the attitudes of the film industry toward black films and black actors are some of the topics examined in this anthology of essays. Section 1, "Nigger to Supernigger," contains such articles as "The Death of Rastus: Negroes in American Films" by Thomas R. Cripps and "Folk Values in a New Medium" by Alain Locke…

  7. Biopolymer nanocomposite films reinforced with nanocellulose whiskers

    Treesearch

    Amit Saxena; Marcus Foston; Mohamad Kassaee; Thomas J. Elder; Arthur J. Ragauskas

    2011-01-01

    A xylan nanocomposite film with improved strength and barrier properties was prepared by a solution casting using nanocellulose whiskers as a reinforcing agent. The 13C cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) analysis of the spectral data obtained for the NCW/xylan nanocomposite films indicated the signal intensity originating...

  8. Cylinder wakes in flowing soap films

    SciTech Connect

    Vorobieff, P.; Ecke, R.E. ); Vorobieff, P. )

    1999-09-01

    We present an experimental characterization of cylinder wakes in flowing soap films. From instantaneous velocity and thickness fields, we find the vortex-shedding frequency, mean-flow velocity, and mean-film thickness. Using the empirical relationship between the Reynolds and Strouhal numbers obtained for cylinder wakes in three dimensions, we estimate the effective soap-film viscosity and its dependence on film thickness. We also compare the decay of vorticity with that in a simple Rankine vortex model with a dissipative term to account for air drag. [copyright] [ital 1999] [ital The American Physical Society

  9. Cylinder wakes in flowing soap films

    NASA Astrophysics Data System (ADS)

    Vorobieff, Peter; Ecke, Robert E.

    1999-09-01

    We present an experimental characterization of cylinder wakes in flowing soap films. From instantaneous velocity and thickness fields, we find the vortex-shedding frequency, mean-flow velocity, and mean-film thickness. Using the empirical relationship between the Reynolds and Strouhal numbers obtained for cylinder wakes in three dimensions, we estimate the effective soap-film viscosity and its dependence on film thickness. We also compare the decay of vorticity with that in a simple Rankine vortex model with a dissipative term to account for air drag.

  10. Health Education Films of the Silent Era: A Historical Analysis

    ERIC Educational Resources Information Center

    Sofalvi, Alan

    2011-01-01

    Films have been used to present health messages throughout the history of the medium. The purpose of this article is to describe pictures from the silent film era that were designed to educate people about health issues. Films still available in at least one format were reviewed. Published reviews were also used to obtain information about these…

  11. Holographic films from carotenoid pigments

    NASA Astrophysics Data System (ADS)

    Toxqui-López, S.; Lecona-Sánchez, J. F.; Santacruz-Vázquez, C.; Olivares-Pérez, A.; Fuentes-Tapia, I.

    2014-02-01

    Carotenoids pigments presents in pineapple can be more than just natural dyes, which is one of the applications that now at day gives the chemical industry. In this research shown that can be used in implementing of holographic recording Films. Therefore we describe the technique how to obtain this kind of pigments trough spay drying of natural pineapple juice, which are then dissolved with water in a proportion of 0.1g to 1mL. The obtained sample is poured into glass substrates using the gravity method, after a drying of 24 hours in laboratory normal conditions the films are ready. The films are characterized by recording transmission holographic gratings (LSR 445 NL 445 nm) and measuring the diffraction efficiency holographic parameter. This recording material has good diffraction efficiency and environmental stability.

  12. Effective Use of Films in Social Studies Classrooms. How To Do It Series, Series 2, No. 2.

    ERIC Educational Resources Information Center

    Bryan, Sam

    The pamphlet reviews uses of films in social studies classrooms, lists sources for obtaining films and filmographies, and gives tips on showing and evaluating the films. Films can be used to illustrate concepts or historical events, communicate the essence of foreign cultures, and enliven dull textbook content. Five types of films are described…

  13. Stress reduction in tungsten films using nanostructured compliant layers

    SciTech Connect

    Karabacak, Tansel; Picu, Catalin R.; Senkevich, Jay J.; Wang, G.-C.; Lu, T.-M.

    2004-11-15

    The residual stress in thin films is a major limiting factor for obtaining high quality films. We present a strategy for stress reduction in sputter deposited films by using a nanostructured compliant layer obtained by the oblique angle deposition technique, sandwiched between the film and the substrate. The technique is all in situ, does not require any lithography steps, and the nanostructured layer is made from the same material as the deposited thin film. By using this approach we were able to reduce stress values by approximately one order of magnitude in sputter deposited tungsten films. These lower stress thin films also exhibit stronger adhesion to the substrate, which retards delamination buckling. This technique allows the growth of much thicker films and has enhanced structural stability. A model is developed to explain the stress relief mechanism and the stronger adhesion associated with the presence of the nanostructured compliant layer.

  14. Directory of Australian Multicultural Films and Videos. A Resource Guide for Community Groups, Teachers, Film-makers, Researchers, Librarians.

    ERIC Educational Resources Information Center

    Best, Alleyn, Comp.

    This directory is a guide to films and videos dealing with migration, migrant issues, and multiculturalism in Australia. Current and archival films are listed and most of the research sources used to obtain the listings are included in the directory. Section 1 lists documentaries and feature films; each citation includes title, production company…

  15. YBa2Cu3O7 thin films on nanocrystalline diamond films for HTSC bolometer

    NASA Technical Reports Server (NTRS)

    Cui, G.; Beetz, C. P., Jr.; Boerstler, R.; Steinbeck, J.

    1993-01-01

    Superconducting YBa2Cu3O(7-x) films on nanocrystalline diamond thin films have been fabricated. A composite buffer layer system consisting of diamond/Si3N4/YSZ/YBCO was explored for this purpose. The as-deposited YBCO films were superconducting with Tc of about 84 K and a relatively narrow transition width of about 8 K. SEM cross sections of the films showed very sharp interfaces between diamond/Si3N4 and between Si3N4/YSZ. The deposited YBCO film had a surface roughness of about 1000 A, which is suitable for high-temperature superconductive (HTSC) bolometer fabrication. It was also found that preannealing of the nanocrystalline diamond thin films at high temperature was very important for obtaining high-quality YBCO films.

  16. YBa2Cu3O7 thin films on nanocrystalline diamond films for HTSC bolometer

    NASA Technical Reports Server (NTRS)

    Cui, G.; Beetz, C. P., Jr.; Boerstler, R.; Steinbeck, J.

    1993-01-01

    Superconducting YBa2Cu3O(7-x) films on nanocrystalline diamond thin films have been fabricated. A composite buffer layer system consisting of diamond/Si3N4/YSZ/YBCO was explored for this purpose. The as-deposited YBCO films were superconducting with Tc of about 84 K and a relatively narrow transition width of about 8 K. SEM cross sections of the films showed very sharp interfaces between diamond/Si3N4 and between Si3N4/YSZ. The deposited YBCO film had a surface roughness of about 1000 A, which is suitable for high-temperature superconductive (HTSC) bolometer fabrication. It was also found that preannealing of the nanocrystalline diamond thin films at high temperature was very important for obtaining high-quality YBCO films.

  17. YBa2Cu3O7 thin films on nanocrystalline diamond films for HTSC bolometer

    NASA Astrophysics Data System (ADS)

    Cui, G.; Beetz, C. P., Jr.; Boerstler, R.; Steinbeck, J.

    1993-03-01

    Superconducting YBa2Cu3O(7-x) films on nanocrystalline diamond thin films have been fabricated. A composite buffer layer system consisting of diamond/Si3N4/YSZ/YBCO was explored for this purpose. The as-deposited YBCO films were superconducting with Tc of about 84 K and a relatively narrow transition width of about 8 K. SEM cross sections of the films showed very sharp interfaces between diamond/Si3N4 and between Si3N4/YSZ. The deposited YBCO film had a surface roughness of about 1000 A, which is suitable for high-temperature superconductive (HTSC) bolometer fabrication. It was also found that preannealing of the nanocrystalline diamond thin films at high temperature was very important for obtaining high-quality YBCO films.

  18. Film: An Introduction.

    ERIC Educational Resources Information Center

    Fell, John L.

    "Understanding Film," the opening section of this book, discusses perceptions of and responses to film and the way in which experiences with and knowledge of other media affect film viewing. The second section, "Film Elements," analyzes the basic elements of film: the use of space and time, the impact of editing, sound and color, and the effects…

  19. Film and History.

    ERIC Educational Resources Information Center

    Schaber, Robin L.

    2002-01-01

    Provides an annotated bibliography of Web sites that focus on using film to teach history. Includes Web sites in five areas: (1) film and education; (2) history of cinema; (3) film and history resources; (4) film and women; and (5) film organizations. (CMK)

  20. International Film Guide 1972.

    ERIC Educational Resources Information Center

    Cowie, Peter, Ed.

    Brief descriptions of film production activity in 44 countries and reviews of important films from these countries are presented, along with lists of films recently in production. A paragraph-long description of film festivals slated for 1972 is given. Sound track music available on records, 16mm films available in the United Kingdom and the…

  1. War. Peace. Film Guide.

    ERIC Educational Resources Information Center

    Dougall, Lucy

    The revised and expanded film guide designed for educators includes annotations of over 200 films, plus a large number of program resources for intelligent film use. Selected from over five hundred films previewed from 1969, up-to-date films were chosen that would help interpret the causes of war, increase awareness of the dehumanizing effects of…

  2. Film and History.

    ERIC Educational Resources Information Center

    Schaber, Robin L.

    2002-01-01

    Provides an annotated bibliography of Web sites that focus on using film to teach history. Includes Web sites in five areas: (1) film and education; (2) history of cinema; (3) film and history resources; (4) film and women; and (5) film organizations. (CMK)

  3. Velocity Field in a Vertical Foam Film

    NASA Astrophysics Data System (ADS)

    Seiwert, Jacopo; Kervil, Ronan; Nou, Soniraks; Cantat, Isabelle

    2017-01-01

    The drainage of vertical foam films governs their lifetime. For a foam film supported on a rectangular solid frame, when the interface presents a low resistance to shear, the drainage dynamics involves a complex flow pattern at the film scale, leading to a drainage time proportional to the frame width. Using an original velocimetry technique, based on fluorescent foam films and photobleaching, we measure the horizontal and vertical components of the velocity in a draining film, thus providing the first quantitative experimental evidence of this flow pattern. Upward velocities up to 10 cm /s are measured close to the lateral menisci, whereas a slower velocity field is obtained in the center of the film, with comparable downwards and horizontal components. Scaling laws are proposed for all characteristic velocities, coupling gravitational effects, and capillary suction.

  4. Fast dissolving films made of maltodextrins.

    PubMed

    Cilurzo, Francesco; Cupone, Irma E; Minghetti, Paola; Selmin, Francesca; Montanari, Luisa

    2008-11-01

    This work aimed to study maltodextrins (MDX) with a low dextrose equivalent as film forming material and their application in the design of oral fast-dissolving films. The suitable plasticizer and its concentration were selected on the basis of flexibility, tensile strength and stickiness of MDX films, and the MDX/plasticizer interactions were investigated by ATR-FTIR spectroscopy. Flexible films were obtained by using 16-20% w/w glycerin (GLY). This basic formulation was adapted to the main production technologies, casting and solvent evaporation (Series C) or hot-melt extrusion (Series E), by adding sorbitan monoleate (SO) or cellulose microcrystalline (MCC), respectively. MCC decreased the film ductility and significantly affected the film disintegration time both in vitro and in vivo (Series C<10s; Series E approximately 1min). To assess the film loading capacity, piroxicam (PRX), a water insoluble drug, was selected. The loading of a drug as a powder decreased the film ductility, but the formulation maintained satisfactory flexibility and resistance to elongation for production and packaging procedures. The films present a high loading capacity, up to 25mg for a surface of 6cm(2). The PRX dissolution rate significantly improved in Series C films independently of the PRX/MDX ratio.

  5. Photophysical properties of Alq3 thin films

    NASA Astrophysics Data System (ADS)

    Zawadzka, A.; Płóciennik, P.; Strzelecki, J.; Łukasiak, Z.; Sahraoui, B.

    2013-11-01

    This work contains investigation results of the photophysical properties of aluminum (III) tris(8-hydroxyquinoline) thin films. The Alq3 thin films were successfully fabricated by Physical Vapor Deposition technique. The films were grown on transparent: (quartz and glass) and semiconductor (n-type silica) substrates kept at room temperature during the deposition process. Selected films were annealed after fabrication in ambient atmosphere for 12 h at the temperature equal to 100 °C and 150 °C. Morphology of the films was investigated by AFM technique. Photophysical properties were characterized via photoluminescence, transmission, second and third harmonic generation measurements. The thin films exhibit high structural quality regardless of the annealing process, but the stability of the film can be improved by using an appropriate temperature during the annealing process. Photoluminescence of Alq3 films obtained in air were efficient and stable. The measurements of transmission, SHG and THG spectra allowed us to determine optical constant of the films. We find that the photophysical properties were strictly connected with the morphology and the annealing process significantly changes the structural properties of the films.

  6. Biodegradable lignin/polyolefin composite films

    SciTech Connect

    Kosikova, B.; Demjanova, V.; Mikulasova, M.; Lora, J.H.

    1993-12-31

    From the view point of environmental protection, the plastic wastes, especially from packing materials, represent a potential waste problem. Various approaches were examined to develop partially or completely biodegradable plastics. New type of partially biodegradable polyolefins was prepared by blending of polypropylene with lignin, which was recovered in the ALCELL process, an organosolv pulping process that uses ethanol-water as the delignifying agent. Films of blends with up to 10% wt ALCELL lignin, prepared in absence of commercial stabilizers, had acceptable mechanical strengths. The effect of lignin on biodegradability of the composite films was examined by comparison of behaviour of both pure and lignin containing films during treatment with fungus Phanerochaete chrysosporium. It was found that this fungus is able to grow and to produce lignolytic enzymes in the presence of the films containing lignin. Biodegradation of lignin in the composite film was confirmed by the releasing of lignin fragments into the extracellular fluid. Because of measurement of mechanical properties offers a mean of direct estimation of polymer degradation, the degree of biodegradation of the films tested was followed by monitoring of elongation at break. The changes of break at elongation in the course of enzymatic treatment revealed that the lignin/PP composite films are potentially environmentally nonpersisting. The micrographs of the lignin containing films obtained by scanning electron microscopy show the significant changes of the film surface upon degradation with Phanerochaete chrysosporium in contrast to unchanged lignin free film.

  7. Buckling of polymerized monomolecular films

    NASA Astrophysics Data System (ADS)

    Bourdieu, L.; Daillant, J.; Chatenay, D.; Braslau, A.; Colson, D.

    1994-03-01

    The buckling of a two-dimensional polymer network at the air-water interface has been evidenced by grazing incidence x-ray scattering. A comprehensive description of the inhomogeneous octadecyltrichlorosilane polymerized film was obtained by atomic force microscopy and x-ray scattering measurements. The buckling occurs with a characteristic wavelength ~=10 μm.

  8. Oil-film-parameter investigation

    NASA Technical Reports Server (NTRS)

    Kingsbury, E. P.

    1972-01-01

    A counter rotating fixture was designed and built to measure starved EHD film thicknesses. Some good geometry glass races were obtained. A theoretical analysis of starvation was made. Measurements of retainer stability during bimode torque disturbances were made. The most common form of bimode was related to stability of retainer cock.

  9. Ferrite thin films for microwave applications

    SciTech Connect

    Zaquine, I.; Benazizi, H.; Mage, J.C.

    1988-11-15

    Production of ferrite thin films is the key to integration of microwave ferrite devices (circulators for phased array antennas, for instance). The interesting materials are the usual microwave ferrites: garnets, lithium ferrites, barium hexaferrites. The required thicknesses are a few tens of micrometers, and it will be important to achieve high deposition rates. Different substrates can be used: silicon and alumina both with and without metallization. The films were deposited by rf sputtering from a single target. The as-deposited films are amorphous and therefore require careful annealing in oxygen atmosphere. The sputtered films are a few micrometers thick on 4 in. substrates. The optimum annealing temperature was found by trying to obtain the highest possible magnetization for each ferrite. The precision on the value of magnetization is limited by the precision on the thickness of the film. We obtain magnetization values slightly lower than the target's. The ferromagnetic resonance linewidth was measured on toroids from 5 to 18 GHz.

  10. Fennel waste-based films suitable for protecting cultivations.

    PubMed

    Mariniello, L; Giosafatto, C V L; Moschetti, G; Aponte, M; Masi, P; Sorrentino, A; Porta, R

    2007-10-01

    Biodegradable, flexible, and moisture-resistant films were obtained by recycling fennel waste and adding to fennel homogenates the bean protein phaseolin that was modified or not modified by the enzyme transglutaminase. All films were analyzed for their morphology, mechanical properties, water vapor permeability, and susceptibility to biodegradation under soil-like conditions. Our experiments showed that transglutaminase treatment of the phaseolin-containing fennel waste homogenates allowed us to obtain films comparable in their mechanical properties and water vapor permeability to the commercial films Ecoflex and Mater-Bi. Furthermore, biodegradability tests demonstrated that the presence of the enzyme in the film-casting sample significantly influences the integrity of such a product that lasts longer than films obtained either with fennel waste alone or with a mixture of fennel waste and phaseolin. These findings indicate the fennel-phaseolin film prepared in the presence of transglutaminase to be a promising candidate for a new environmentally friendly mulching bioplastic.

  11. Ferroelectric ultrathin perovskite films

    DOEpatents

    Rappe, Andrew M; Kolpak, Alexie Michelle

    2013-12-10

    Disclosed herein are perovskite ferroelectric thin-film. Also disclosed are methods of controlling the properties of ferroelectric thin films. These films can be used in a variety materials and devices, such as catalysts and storage media, respectively.

  12. Filming The Man Hunters

    ERIC Educational Resources Information Center

    Hockings, Paul

    1976-01-01

    "The Man Hunters" is a film about paleoanthropology. This article is a personal account of how the film was put together using anthropological knowledge and numerous anthropologists and how the film was received by the American public. (Author)

  13. Water-evaporation reduction by duplex films: application to the human tear film.

    PubMed

    Cerretani, Colin F; Ho, Nghia H; Radke, C J

    2013-09-01

    Water-evaporation reduction by duplex-oil films is especially important to understand the physiology of the human tear film. Secreted lipids, called meibum, form a duplex film that coats the aqueous tear film and purportedly reduces tear evaporation. Lipid-layer deficiency is correlated with the occurrence of dry-eye disease; however, in-vitro experiments fail to show water-evaporation reduction by tear-lipid duplex films. We review the available literature on water-evaporation reduction by duplex-oil films and outline the theoretical underpinnings of spreading and evaporation kinetics that govern behavior of these systems. A dissolution-diffusion model unifies the data reported in the literature and identifies dewetting of duplex films into lenses as a key challenge to obtaining significant evaporation reduction. We develop an improved apparatus for measuring evaporation reduction by duplex-oil films including simultaneous assessment of film coverage, stability, and temperature, all under controlled external mass transfer. New data reported in this study fit into the larger body of work conducted on water-evaporation reduction by duplex-oil films. Duplex-oil films of oxidized mineral oil/mucin (MOx/BSM), human meibum (HM), and bovine meibum (BM) reduce water evaporation by a dissolution-diffusion mechanism, as confirmed by agreement between measurement and theory. The water permeability of oxidized-mineral-oil duplex films agrees with those reported in the literature, after correction for the presence of mucin. We find that duplex-oil films of bovine and human meibum at physiologic temperature reduce water evaporation only 6-8% for a 100-nm film thickness pertinent to the human tear film. Comparison to in-vivo human tear-evaporation measurements is inconclusive because evaporation from a clean-water surface is not measured and because the mass-transfer resistance is not characterized. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Development and characterization of biodegradable films made from wheat gluten protein fractions.

    PubMed

    Hernández-Muñoz, Pilar; Kanavouras, Antonis; Ng, Perry K W; Gavara, Rafael

    2003-12-17

    Gliadins and glutenins were extracted from commercial wheat gluten on the basis of their extractability in ethanol and used to produce film-forming solutions. Films cast using these gliadin- and glutenin-rich solutions were characterized. Glycerol was used as a plasticizer, and its effect on the films was also studied. Films obtained from the glutenin fraction presented higher tensile strength values and lower elongation at break and water vapor permeability values than gliadin films. Gliadin films disintegrated when immersed in water. The GAB isotherm model was used to describe the equilibrium moisture sorption of the films. The glycerol concentration largely modified mechanical and water vapor barrier properties of both film types.

  15. Nonlinear optical thin films

    NASA Technical Reports Server (NTRS)

    Leslie, Thomas M.

    1993-01-01

    A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film

  16. Nonlinear optical thin films

    NASA Technical Reports Server (NTRS)

    Leslie, Thomas M.

    1993-01-01

    A focused approach to development and evaluation of organic polymer films for use in optoelectronics is presented. The issues and challenges that are addressed include: (1) material synthesis, purification, and the tailoring of the material properties; (2) deposition of uniform thin films by a variety of methods; (3) characterization of material physical properties (thermal, electrical, optical, and electro-optical); and (4) device fabrication and testing. Photonic materials, devices, and systems were identified as critical technology areas by the Department of Commerce and the Department of Defense. This approach offers strong integration of basic material issues through engineering applications by the development of materials that can be exploited as the active unit in a variety of polymeric thin film devices. Improved materials were developed with unprecedented purity and stability. The absorptive properties can be tailored and controlled to provide significant improvement in propagation losses and nonlinear performance. Furthermore, the materials were incorporated into polymers that are highly compatible with fabrication and patterning processes for integrated optical devices and circuits. By simultaneously addressing the issues of materials development and characterization, keeping device design and fabrication in mind, many obstacles were overcome for implementation of these polymeric materials and devices into systems. We intend to considerably improve the upper use temperature, poling stability, and compatibility with silicon based devices. The principal device application that was targeted is a linear electro-optic modulation etalon. Organic polymers need to be properly designed and coupled with existing integrated circuit technology to create new photonic devices for optical communication, image processing, other laser applications such as harmonic generation, and eventually optical computing. The progression from microscopic sample to a suitable film

  17. Growth of single crystalline germanium thin film on (100) silicon substrate

    NASA Astrophysics Data System (ADS)

    Kim, Sung Wook; Lee, Jaejun; Park, Youn Ho; Park, Jeong Min; Park, Sangwon; Kim, Yeon Joo; Choi, Heon-Jin

    2017-03-01

    Epitaxial growth of germanium thin films (GeTFs) on Si (111) and Si (100) substrates was investigated, and the prepared films were compared with the films grown on SiO2 substrates. Ge films were prepared in three steps. Initially, a Ge interlayer film with thickness of ˜ 10 nm was deposited on the substrate followed by annealing and recrystallization of the film. A Ge film with a thickness of 500 nm was then deposited. A single crystalline Ge film was grown on Si (100) whereas polycrystalline films were grown on the other substrates. The growth rate of the films depends on the type of the substrates used, which in turn determines the crystallinity of the films. Highly crystalline films were obtained with slow growth rates. The single crystalline epitaxial layer of GeTFs formed on Si (100) exhibited a lower threading dislocation density as compared with those grown on Si (111) and SiO2.

  18. AC impedance analysis of polypyrrole thin films

    NASA Technical Reports Server (NTRS)

    Penner, Reginald M.; Martin, Charles R.

    1987-01-01

    The AC impedance spectra of thin polypyrrole films were obtained at open circuit potentials from -0.4 to 0.4 V vs SCE. Two limiting cases are discussed for which simplified equivalent circuits are applicable. At very positive potentials, the predominantly nonfaradaic AC impedance of polypyrrole is very similar to that observed previously for finite porous metallic films. Modeling of the data with the appropriate equivalent circuit permits effective pore diameter and pore number densities of the oxidized film to be estimated. At potentials from -0.4 to -0.3 V, the polypyrrole film is essentially nonelectronically conductive and diffusion of polymer oxidized sites with their associated counterions can be assumed to be linear from the film/substrate electrode interface. The equivalent circuit for the polypyrrole film at these potentials is that previously described for metal oxide, lithium intercalation thin films. Using this model, counterion diffusion coefficients are determined for both semi-infinite and finite diffusion domains. In addition, the limiting low frequency resistance and capacitance of the polypyrrole thin fims was determined and compared to that obtained previously for thicker films of the polymer. The origin of the observed potential dependence of these low frequency circuit components is discussed.

  19. Ferromagnetic properties of fcc Gd thin films

    SciTech Connect

    Bertelli, T. P. Passamani, E. C.; Larica, C.; Nascimento, V. P.; Takeuchi, A. Y.

    2015-05-28

    Magnetic properties of sputtered Gd thin films grown on Si (100) substrates kept at two different temperatures were investigated using X-ray diffraction, ac magnetic susceptibility, and dc magnetization measurements. The obtained Gd thin films have a mixture of hcp and fcc structures, but with their fractions depending on the substrate temperature T{sub S} and film thickness x. Gd fcc samples were obtained when T{sub S} = 763 K and x = 10 nm, while the hcp structure was stabilized for lower T{sub S} (300 K) and thicker film (20 nm). The fcc structure is formed on the Ta buffer layer, while the hcp phase grows on the fcc Gd layer as a consequence of the lattice relaxation process. Spin reorientation phenomenon, commonly found in bulk Gd species, was also observed in the hcp Gd thin film. This phenomenon is assumed to cause the magnetization anomalous increase observed below 50 K in stressed Gd films. Magnetic properties of fcc Gd thin films are: Curie temperature above 300 K, saturation magnetization value of about 175 emu/cm{sup 3}, and coercive field of about 100 Oe at 300 K; features that allow us to classify Gd thin films, with fcc structure, as a soft ferromagnetic material.

  20. Treating Surfaces To Obtain Narrowband Thermal Emission

    NASA Technical Reports Server (NTRS)

    Burger, Dale R.; Ong, Tiong P.

    1993-01-01

    Surfaces emitting electromagnetic radiation predominantly in desired narrow spectral bands when heated made more durable, and fabricated less expensively, according to proposal. Narrowband thermal emitters made by polishing metal substrates to specularity, then coating specular surfaces with films of rare-earth oxides approximately less than 1 micrometer thick. Metal substrates inherently resistant to mechanical shock. Resistance to thermal shock achieved by choosing metals and rare-earth oxides having equal or nearly equal coefficients of thermal expansion.

  1. Hydrogen film/conductive cooling

    NASA Technical Reports Server (NTRS)

    Ewen, R. L.

    1972-01-01

    Small scale nozzle tests using heated nitrogen were run to obtain effectiveness and wall heat transfer data with hydrogen film cooling. Effectiveness data are compared with an entrainment model developed from planar, unaccelerated flow data. Results indicate significant effects due to flow turning and acceleration. With injection velocity effects accounted for explicitly, heat transfer correlation coefficients were found to be the same with and without film cooling when properties are evaluated at an appropriate reference temperature for the local gas composition defined by the coolant effectiveness. A design study for an O2/H2 application with 300 psia (207 N/sq cm) chamber pressure and 1500 lbs (6670 N) thrust indicates an adiabatic wall design requires 4 to 5 percent of the total flow as hydrogen film cooling. Internal regenerative cooling designs were found to offer no reduction in coolant requirements.

  2. Role of asphaltenes in stabilizing thin liquid emulsion films.

    PubMed

    Tchoukov, Plamen; Yang, Fan; Xu, Zhenghe; Dabros, Tadeusz; Czarnecki, Jan; Sjöblom, Johan

    2014-03-25

    Drainage kinetics, thickness, and stability of water-in-oil thin liquid emulsion films obtained from asphaltenes, heavy oil (bitumen), and deasphalted heavy oil (maltenes) diluted in toluene are studied. The results show that asphaltenes stabilize thin organic liquid films at much lower concentrations than maltenes and bitumen. The drainage of thin organic liquid films containing asphaltenes is significantly slower than the drainage of the films containing maltenes and bitumen. The films stabilized by asphaltenes are much thicker (40-90 nm) than those stabilized by maltenes (∼10 nm). Such significant variation in the film properties points to different stabilization mechanisms of thin organic liquid films. Apparent aging effects, including gradual increase of film thickness, rigidity of oil/water interface, and formation of submicrometer size aggregates, were observed for thin organic liquid films containing asphaltenes. No aging effects were observed for films containing maltenes and bitumen in toluene. The increasing stability and lower drainage dynamics of asphaltene-containing thin liquid films are attributed to specific ability of asphaltenes to self-assemble and form 3D network in the film. The characteristic length of stable films is well beyond the size of single asphaltene molecules, nanoaggregates, or even clusters of nanoaggregates reported in the literature. Buildup of such 3D structure modifies the rheological properties of the liquid film to be non-Newtonian with yield stress (gel like). Formation of such network structure appears to be responsible for the slower drainage of thin asphaltenes in toluene liquid films. The yield stress of liquid film as small as ∼10(-2) Pa is sufficient to stop the drainage before the film reaches the critical thickness at which film rupture occurs.

  3. Evaluation of therapeutic pulmonary surfactants by thin liquid film methods.

    PubMed

    Todorov, Roumen; Exerowa, Dotchi; Platikanov, Dimo; Bianco, Federico; Razzetti, Roberta

    2015-08-01

    An example of the application of the Black Foam Film (BFF) Method and the Wetting Film Method, using the Microinterferomertric and the Pressure Balance Techniques, for characterization interfacial properties of the animal derived therapeutic pulmonary surfactant preparations (TSP), is presented. BFF thickness, probability of black film formation, and disjoining pressure for foam films from TSP aqueous solutions are measured as well as the wetting properties of TSP solutions on solid surfaces with different hydrophobicity have been studied. Interfacial characteristics such as minimal surfactant concentration to obtain black film (critical concentration) and concentration at which a black film is 100% obtained (threshold concentration) are determined. An evaluation of the four widely used TSP – Curosurf, Infasurf, Survanta, and Alveofact – by these methods has been carried out. Thus the methods of the thin liquid films are useful tools for studying the interfacial properties of TSP solutions, as well as for their improvement.

  4. Spin current relaxation time in thermally evaporated pentacene films

    NASA Astrophysics Data System (ADS)

    Tani, Yasuo; Kondo, Takuya; Teki, Yoshio; Shikoh, Eiji

    2017-01-01

    The spin current relaxation time (τ) in thermally evaporated pentacene films was evaluated with the spin-pump-induced spin transport properties and the charge current transport properties in pentacene films. Under an assumption of a diffusive transport of the spin current in pentacene films, the zero-field mobility and the diffusion constant of holes in pentacene films were experimentally obtained to be ˜8.0 × 10-7 m2/V s and ˜2.0 × 10-8 m2/s, respectively. Using those values and the previously obtained spin diffusion length in pentacene films of 42 ± 10 nm, the τ in pentacene films was estimated to be 150 ± 120 ns at room temperature. This estimated τ in pentacene films is long enough for the practical use as a spintronic material.

  5. Enhanced removal of bilirubin on molecularly imprinted titania film.

    PubMed

    Yang, Zheng-peng; Yan, Jin-long; Zhang, Chun-jing; Luo, Shu-qiong

    2011-10-01

    Titania film imprinted by bilirubin molecule at the surface of quartz crystal was prepared using molecular imprinting and surface sol-gel process. The molecularly imprinted titania film was characterized by FTIR spectra, and the interaction between bilirubin and imprinted film was investigated using quartz crystal microbalance (QCM) technique. Compared with pure titania film, the molecularly imprinted titania film exhibits a much higher adsorption capacity for the target molecule, and the adsorption kinetic parameter estimated from the in situ frequency measurement is about 1.6×10(8) M(-1), which is ten times higher than that obtained on pure titania film. The photocatalytic measurements indicate that the bilirubin adsorbed on molecularly imprinted titania film can be completely removed under UV illumination. Moreover, our study indicates that the molecularly imprinted titania film possesses a better stability and reusability.

  6. Thin films under chemical stress

    SciTech Connect

    Not Available

    1991-01-01

    The goal of work on this project has been develop a set of experimental tools to allow investigators interested in transport, binding, and segregation phenomena in composite thin film structures to study these phenomena in situ. Work to-date has focuses on combining novel spatially-directed optical excitation phenomena, e.g. waveguide eigenmodes in thin dielectric slabs, surface plasmon excitations at metal-dielectric interfaces, with standard spectroscopies to understand dynamic processes in thin films and at interfaces. There have been two main scientific thrusts in the work and an additional technical project. In one thrust we have sought to develop experimental tools which will allow us to understand the chemical and physical changes which take place when thin polymer films are placed under chemical stress. In principle this stress may occur because the film is being swelled by a penetrant entrained in solvent, because interfacial reactions are occurring at one or more boundaries within the film structure, or because some component of the film is responding to an external stimulus (e.g. pH, temperature, electric field, or radiation). However all work to-date has focused on obtaining a clearer understanding penetrant transport phenomena. The other thrust has addressed the kinetics of adsorption of model n-alkanoic acids from organic solvents. Both of these thrusts are important within the context of our long-term goal of understanding the behavior of composite structures, composed of thin organic polymer films interspersed with Langmuir-Blodgett (LB) and self-assembled monolayers. In addition there has been a good deal of work to develop the local technical capability to fabricate grating couplers for optical waveguide excitation. This work, which is subsidiary to the main scientific goals of the project, has been successfully completed and will be detailed as well. 41 refs., 10 figs.

  7. Films on Oceanography.

    ERIC Educational Resources Information Center

    Cuzon du Rest, R. P.

    This film list compiled by the U.S. Naval Oceanographic Office is separated into six categories: general oceanography, biology, chemistry, engineering, geology, and physics. An index of films is followed by addresses of Naval Districts and lists of distribution centers. Each film listed is described as to content, running time, type of film,…

  8. Film Presentation Techniques.

    ERIC Educational Resources Information Center

    Monod, Pierre

    1976-01-01

    This article discusses three types of films and their use in the second language classroom. The description film is objective and static, and elicits adjectives and adverbs. This kind of film should be presented three times, each time followed by a different set of learning exercises. The culture film - characterized by descriptions, scenes from…

  9. [Films: China and Japan].

    ERIC Educational Resources Information Center

    Gumport, Roberta H.

    The history of filmmaking in China and Japan and film usage in teaching are considered in this document. Pointing out how films describe historical context and culture, the document also describes various techniques of film making. Films in China were heavily influenced by western models and have tended to be tools of the power structure, as…

  10. Thin film interference of colloidal thin films.

    PubMed

    Cong, Hailin; Cao, Weixiao

    2004-09-14

    A stairlike colloidal crystal thin film composed of poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) monodispersed colloids was fabricated on an inclined silicon substrate. Different bright colors were observed on the various parts of the film with different layers as white light irradiated perpendicularly on it. The relationship between the colors and layers of the film was investigated and discussed according to the principle of thin film interference. On the basis of the phenomenon of thin film interference, a one-layer colloidal film having uniform color was researched and it would display diverse colors before and after swollen by styrene (St). A circular stairlike colloidal film was achieved to mimic the colors of the peacock tail feather.

  11. Properties and microstructure of thermo-pressed wheat gluten films: a comparison with cast films.

    PubMed

    Mangavel, C; Rossignol, N; Perronnet, A; Barbot, J; Popineau, Y; Guéguen, J

    2004-01-01

    Wheat gluten films were prepared by thermo-pressing, and their mechanical properties were compared to those of cast films. The stress-strain relationship was established for films with various amounts of glycerol. Both relationships were quite different, revealing a different network organization. Thermo-pressed films presented higher stress values than cast films, but the effect of the glycerol amount was similar in both cases, an increase of the glycerol amount leading to a decrease of both films stress. The glycerol influence on the strain at break of thermo-pressed films was very limited, with strain values reaching a maximum around 200%. The role of disulfide bridges on themomoulded films mechanical properties was investigated, and it was shown that some rearrangements and a significative protein insolubilization occurred during the process. The effective flow porosity of the protein network for thermo-pressed films was estimated by water capillary rise measurements to about 7%. Scanning electron microscopy was used to obtain some information about the microstructure of both cast and thermo-pressed films.

  12. Hydrogen film cooling investigation

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.; Ewen, R. L.

    1973-01-01

    Effects of flow turning, flow acceleration, and supersonic flow on film cooling were determined experimentally and correlated in terms of an entrainment film cooling model. Experiments were conducted using thin walled metal test sections, hot nitrogen mainstream gas, and ambient hydrogen or nitrogen as film coolants. The entrainment film cooling model relates film cooling effectiveness to the amount of mainstream gases entrained with the film coolant in a mixing layer. The experimental apparatus and the analytical model used are described in detail and correlations for the entrainment fraction and film coolant-to-wall heat transfer coefficient are presented.

  13. Carbon thin film thermometry

    NASA Technical Reports Server (NTRS)

    Collier, R. S.; Sparks, L. L.; Strobridge, T. R.

    1973-01-01

    The work concerning carbon thin film thermometry is reported. Optimum film deposition parameters were sought on an empirical basis for maximum stability of the films. One hundred films were fabricated for use at the Marshall Space Flight Center; 10 of these films were given a precise quasi-continuous calibration of temperature vs. resistance with 22 intervals between 5 and 80 K using primary platinum and germanium thermometers. Sensitivity curves were established and the remaining 90 films were given a three point calibration and fitted to the established sensitivity curves. Hydrogen gas-liquid discrimination set points are given for each film.

  14. Decreased group velocity in compositionally graded films.

    PubMed

    Gao, Lei

    2006-03-01

    A theoretical formalism is presented that describes the group velocity of electromagnetic signals in compositionally graded films. The theory is first based on effective medium approximation or the Maxwell-Garnett approximation to obtain the equivalent dielectric function in a z slice. Then the effective dielectric tensor of the graded film is directly determined, and the group velocities for ordinary and extraordinary waves in the film are derived. It is found that the group velocity is sensitively dependent on the graded profile. For a power-law graded profile f(x)=ax(m), increasing m results in the decreased extraordinary group velocity. Such a decreased tendency becomes significant when the incident angle increases. Therefore the group velocity in compositionally graded films can be effectively decreased by our suitable adjustment of the total volume fraction, the graded profile, and the incident angle. As a result, the compositionally graded films may serve as candidate material for realizing small group velocity.

  15. Dynamical mechanism of the liquid film motor.

    PubMed

    Liu, Zhong-Qiang; Li, Ying-Jun; Zhang, Guang-Cai; Jiang, Su-Rong

    2011-02-01

    The paper presents a simple dynamical model to systemically explain the rotation mechanism of the liquid film motor reported by experiments. The field-induced-plasticity effect of the liquid film is introduced into our model, in which the liquid film in crossed electric fields is considered as a Bingham plastic fluid with equivalent electric dipole moment. Several analytic results involving the torque of rotation, the scaling relation of the threshold fields, and the dynamics equation of a square film and its solution are obtained. We find that the rotation of the liquid film motor originates from the continuous competition between the destruction and the reestablishment of the polarization equilibrium maintained by the external electric field, which is free from the boundary effects. Most experimental phenomena observed in direct current electric fields are interpreted well.

  16. Electrical resistivity of thin bismuth films

    NASA Astrophysics Data System (ADS)

    Kumar, A.; Katyal, O. P.

    1990-05-01

    The effect of the film thickness of a bismuth film deposited on glass substrate on its electrical resistivity was investigated for films from 41 to 225 nm thickness, in the temperature range 77-350 K. Results show that the electrical resistivity decreases with increasing temperature and that, for films 98.3 and 225.9 nm thick there exists a minimum (between 260 and 350 K) in resistivity at some temperature, Tc. This minimum shifts toward higher temperature for thinner samples, and lies above 350 K. The thickness dependence of the bismuth film resistivity, obtained at 77, 150, and 300 K, can be explained by a modified Fuchs model, which takes into account the thickness dependence of carrier density.

  17. Durable solar mirror films

    DOEpatents

    O'Neill, Mark B.; Henderson, Andrew J.; Hebrink, Timothy J.; Katare, Rajesh K.; Jing, Naiyong; North, Diane; Peterson, Eric M.

    2017-02-14

    The present disclosure generally relates to durable solar mirror films, methods of making durable solar mirror films, and constructions including durable solar mirror films. In one embodiment, the present disclosure relates to a solar mirror film comprising: a multilayer optical film layer including having a coefficient of hygroscopic expansion of less than about 30 ppm per percent relative humidity; and a reflective layer having a coefficient of hygroscopic expansion.

  18. Poly-para-xylylene thin films: A study of the deposition chemistry, kinetics, film properties, and film stability

    NASA Astrophysics Data System (ADS)

    Fortin, Jeffrey Bernard

    Poly-para-xylylene, or parylene, thin films are chemically vapor deposited (CVD), conformal, pin-hole free polymeric thin films. They have found many industrial uses since there invention in 1947 and continue to find new applications in micro-electronics, biotechnology, and micro-electro-mechanical systems. In this study the deposition chemistry, deposition kinetics, film properties, and film stability were investigated. A differentially pumped quadrupole mass spectrometer was used to analyze the vapor species present during the CVD process. The identity of dimer contamination and its impact on the CVD process and film properties was studied. The quantitative conversion of dimer to monomer was investigated and it was found that conversion begins at around 385°C and by 565°C 100% conversion is obtained. The kinetics of the CVD process was analyzed for a range of substrate temperatures and chamber pressures. A new kinetic model based on a two-step adsorption was developed and fit the kinetic data well. This model should be appropriate for use with all parylene family polymers. Many of the properties of the films deposited in this study were analyzed. This includes a detailed study of surface morphology using atomic force microscopy which shows the interface width increases as a power law of film thickness. Other properties analyzed were the thermal stability, electrical properties, index of refraction, birefringence, hardness, and elastic modulus. The effect of ultraviolet (UV) radiation of lambda ≥ 250 nm on the thermal stability, electrical, and optical properties of thin parylene films was studied. The thermal stability and electrical properties of UV treated films were seen to deteriorate as the radiation dose increased. The stability of parylene thin films receiving plasma etching was analyzed. The dielectric constant, dissipation factor, and leakage current of plasma etched thin parylene films were investigated and found to be stable for the range of

  19. Electroplated Fe films prepared from a deep eutectic solvent

    NASA Astrophysics Data System (ADS)

    Yanai, T.; Shiraishi, K.; Shimokawa, T.; Watanabe, Y.; Ohgai, T.; Nakano, M.; Suzuki, K.; Fukunaga, H.

    2014-05-01

    Electroplating of Fe films was carried out from choline chloride-ethylene glycol types of DES (Deep Eutectic Solvent). We investigated magnetic properties of the plated Fe films and evaluated the productivity for the electroplating process. Consequently, we found that surface morphology and current efficiency of the plated films were affected by the bath temperature. We obtained the Fe films with relatively smooth surface and high current efficiency in the bath temperature range from 70 to 110 °C. The deposition rate for our process depended on the current density, and we obtained high deposition rate value of approximately 120 μm/h. We also obtained high current efficiency values of approximately 90% in the wide range of plating time. These results indicate that the DES-based bath has industrial advantages for mass-producing Fe films. Therefore, we conclude that the DES-based bath is an attractive plating bath for Fe films.

  20. Interferometric measurement method of thin film thickness based on FFT

    NASA Astrophysics Data System (ADS)

    Shuai, Gaolong; Su, Junhong; Yang, Lihong; Xu, Junqi

    2009-05-01

    The kernel of modern interferometry is to obtain necessary surface shape and parameter by processing interferogram with reasonable algorithm. The paper studies the basic principle of interferometry involving 2-D FFT, proposes a new method for measuring thin film thickness based on FFT: by CCD receiving and acquired card collecting with the help of Twyman-Green interferometer, can a fringe interferogram of the measured thin film be obtained. Based on the interferogram processing knowledge, an algorithm processing software/program can be prepared to realize identification of the edge films, regional extension, filtering, unwrapping the wrapped phase etc. And in this way can the distribution of film information-coated surface be obtained and the thickness of thin film samples automatically measured. The findings indicate the PV value and RMS value of the measured film samples are 0.256 λ and 0.068 λ respectively and prove the new method has high precision.

  1. Fabrication of alumina films with laminated structures by ac anodization.

    PubMed

    Segawa, Hiroyo; Okano, Hironaga; Wada, Kenji; Inoue, Satoru

    2014-02-01

    Anodization techniques by alternating current (ac) are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50-200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials.

  2. 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.

  3. Integrated thin film cadmium sulfide solar cell module

    NASA Technical Reports Server (NTRS)

    Mickelsen, R. A.; Abbott, D. D.

    1971-01-01

    The design, development, fabrication and tests of flexible integrated thin-film cadmium sulfide solar cells and modules are discussed. The development of low cost and high production rate methods for interconnecting cells into large solar arrays is described. Chromium thin films were applied extensively in the deposited cell structures as a means to: (1) achieve high adherence between the cadmium sulfide films and the vacuum-metallized copper substrates, (2) obtain an ohmic contact to the cadmium sulfide films, and (3) improve the adherence of gold films as grids or contact areas.

  4. Fabrication of alumina films with laminated structures by ac anodization

    NASA Astrophysics Data System (ADS)

    Segawa, Hiroyo; Okano, Hironaga; Wada, Kenji; Inoue, Satoru

    2014-02-01

    Anodization techniques by alternating current (ac) are introduced in this review. By using ac anodization, laminated alumina films are fabricated. Different types of alumina films consisting of 50-200 nm layers were obtained by varying both the ac power supply and the electrolyte. The total film thickness increased with an increase in the total charge transferred. The thickness of the individual layers increased with the ac voltage; however, the anodization time had little effect on the film thickness. The laminated alumina films resembled the nacre structure of shells, and the different morphologies exhibited by bivalves and spiral shells could be replicated by controlling the rate of increase of the applied potentials.

  5. Multiple spectrum analysis and evaluation for optical constants of HfO2 thin films

    NASA Astrophysics Data System (ADS)

    Liu, Dandan; Liu, Huasong; Jiang, Chenghui; Jiang, Yugang; Wang, Lishuan; Zhao, Zhihong; Ji, Yiqin

    2014-08-01

    HfO2 thin films were deposited on ZS1 silica by Ion Beam Sputtering (IBS) technique. Optical constants of HfO2 thin films were obtained by multiple spectrum analysis method, which combined the transmittance spectrum and ellipsometry spectrum of the film. The refractive index and extinction coiefficient of HfO2 thin films were evaluated by etching experiments of the film. The analysis spectral range was between 250nm and 850nm.

  6. Theory of elastic wave propagation in anisotropic film on anisotropic substrate: TiN film on single-crystal Si.

    PubMed

    Tewary, V K

    2002-09-01

    The delta-function representation of the elastodynamic Green's function is used to derive an expression for the elastic wave forms on the surface of an anisotropic thin film on an anisotropic substrate due to a point or a line source located at the surface of the film. The dispersion relation for surface acoustic waves (SAWs) is obtained from the poles of the Green's function. A computationally efficient algorithm is formulated to obtain the elastic constants and the density of the film from the SAW dispersion data. The theory is used to analyze measured SAW dispersion relations in a titanium nitride film on silicon. The analysis yields values of the elastic constants and the density of the film. Excellent agreement is obtained between the theoretical and experimental dispersion results. Calculated wave forms for the surface wave due to a pulsed line source on the surface of the film are reported.

  7. 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.

  8. Functional Films from Silica/Polymer Nanoparticles

    PubMed Central

    Ribeiro, Tânia; Baleizão, Carlos; Farinha, José Paulo S.

    2014-01-01

    High performance functional coatings, based on hybrid organic/inorganic materials, are being developed to combine the polymer flexibility and ease of processing with the mechanical properties and versatility of inorganic materials. By incorporating silica nanoparticles (SiNPs) in the polymeric matrices, it is possible to obtain hybrid polymer films with increased tensile strength and impact resistance, without decreasing the flexural properties of the polymer matrix. The SiNPs can further be used as carriers to impart other functionalities (optical, etc.) to the hybrid films. By using polymer-coated SiNPs, it is possible to reduce particle aggregation in the films and, thus, achieve more homogeneous distributions of the inorganic components and, therefore, better properties. On the other hand, by coating polymer particles with silica, one can create hierarchically structured materials, for example to obtain superhydrophobic coatings. In this review, we will cover the latest developments in films prepared from hybrid polymer/silica functional systems. PMID:28788655

  9. Functional properties of chitosan-based films.

    PubMed

    Leceta, I; Guerrero, P; de la Caba, K

    2013-03-01

    Chitosan-based films plasticized with glycerol were prepared by casting with the aim to obtain environmentally friendly materials for packaging applications. Different contents of glycerol were incorporated into chitosan solutions to improve mechanical properties and all films obtained were flexible and transparent. It was observed that the transparency and good behaviour of the films against UV radiation were not affected by chitosan molecular weight or glycerol content. Moreover, chitosan-based films exhibited excellent barrier properties against water vapour and oxygen, even with the addition of glycerol. The effect of the plasticizer on the properties has been explained using Fourier transform infrared (FTIR) spectroscopic analysis. The changes observed in the intensity of the bands showed that glycerol interacts with chitosan, which could be confirmed by total soluble matter (TSM). Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Optical dispersion relations for diamondlike carbon films

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Sieg, Robert M.; Shoemaker, Neil S.; Pouch, John J.

    1989-01-01

    Ellipsometric measurements on plasma deposited diamondlike amorphous carbon (a-C:H) films were taken in the visible, (E=1.75 to 3.5 eV). The films were deposited on Si and their properties were varied using high temperature (up to 750 C) anneals. The real (n) and imaginary (k) parts of the complex index of refraction N were obtained simultaneously. Following the theory of Forouhi and Bloomer, a least squares fit was used to find the dispersion relations n(E) and k(E). Reasonably good fits were obtained, showing that the theory can be used for a-C:H films. Moreover, the value of the energy gap (Eg) obtained in this way was compared to the Eg value using conventional Tauc plots and reasonably good agreement was obtained.

  11. Optical dispersion relations for diamondlike carbon films

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Sieg, Robert M.; Shoemaker, Neil S.; Pouch, John J.

    1990-01-01

    Ellipsometric measurements on plasma deposited diamondlike amorphous carbon (a-C:H) films were taken in the visible, (E = 1.75 to 3.5 eV). The films were deposited on Si and their properties were varied using high temperature (up to 750 C) anneals. The real (n) and imaginary (k) parts of the complex index of refraction, N, were obtained simultaneously. Following the theory of Forouhi and Bloomer, a least squares fit was used to find the dispersion relations n(E) and k(E). Reasonably good fits were obtained, showing that the theory can be used for a-C:H films. Moreover, the value of the energy gap, Eg, obtained in this way was compared the the Eg value using conventional Tauc plots and reasonably good agreement was obtained.

  12. Optical dispersion relations for 'diamondlike' carbon films

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Sieg, Robert M.; Shoemaker, Neil S.; Pouch, John J.

    1989-01-01

    Ellipsometric measurements on plasma deposited diamondlike amorphous carbon (a-C:H) films were taken in the visible, (E = 1.75 to 3.5 eV). The films were deposited on Si and their properties were varied using high temperature (up to 750 C) anneals. The real (n) and imaginary (k) parts of the complex index of refraction N were obtained simultaneously. Following the theory of Forouhi and Bloomer, a least squares fit was used to find the dispersion relations n(E) and k(E). Reasonably good fits were obtained, showing that the theory can be used for a-C:H films. Moreover, the value of the energy gap (Eg) obtained in this way was compared to the Eg value using conventional Tauc plots and reasonably good agreement was obtained.

  13. Recent advances in screen-film mammography

    SciTech Connect

    Haus, A.G.

    1987-09-01

    Today there are many dedicated mammographic x-ray units available that are capable of providing high-quality screen-film mammograms. Likewise, screen-film combinations designed for mammography are capable of providing images with appropriate contrast, resolution, and noise levels. Proper film processing is most important in order to obtain the appropriate film speed and contrast. A higher-speed screen-film combination designed for mammography can provide mammograms with significantly lower radiation dose, especially for grid and magnification techniques. Designing x-ray units and techniques as well as screen-film combinations with the singular goal of reducing radiation dose will always involve compromises and trade-offs. The key is to always consider optimizing all of the factors that affect image quality: (1) appropriate beam quality, (2) breast compression, (3) consideration of the use of grids, (4) good geometry, (5) selection of an appropriate screen-film combination, and (6) proper film processing. Optimization of all appropriate imaging factors will produce high-quality mammograms at the lowest radiation dose to the patient.52 references.

  14. Testing Solutions for Adult Film Performers.

    PubMed

    Bergman, Zachary R

    2014-01-01

    The majority of the nation's adult films are produced in California, and within California, most production occurs in Los Angeles. In order to regulate that content, the County of Los Angeles passed the Safer Sex in the Adult Film Industry Act (Measure B) by way of referendum in November 2012. Measure B requires that adult film producers wishing to film in Los Angeles County obtain permits from the Los Angeles County Department of Public Health, and it also mandates that adult film performers use condoms while filming and "engaging in anal or vaginal sexual intercourse." Nevertheless, between August 2013 and January 2014, several adult film performers in California tested positive for HIV, and the threat of infection remains. Although Measure B is not the best way forward for Los Angeles County, elements of the ordinance should be incorporated into future legislative efforts. Given the economic ramifications of industry flight due to more localized regulations, this Note concludes that California should pass statewide comprehensive reform. Any such new legislation must treat "independent contractors," the classification generally used for adult film performs, as if they were regular employees. Legislation should also couple mandatory testing mechanisms with provisions granting performers the right to choose whether they use condoms. Finally, legislation must include mechanisms that ensure performers' preferences are not improperly tainted by outside forces and pressures. While there will always be risks associated with the production of adult content, if undertaken, these reforms could significantly mitigate those hazards.

  15. Electronic structure investigation of biphenylene films

    NASA Astrophysics Data System (ADS)

    Totani, R.; Grazioli, C.; Zhang, T.; Bidermane, I.; Lüder, J.; de Simone, M.; Coreno, M.; Brena, B.; Lozzi, L.; Puglia, C.

    2017-02-01

    Photoelectron Spectroscopy (PS) and Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy have been used to investigate the occupied and empty density of states of biphenylene films of different thicknesses, deposited onto a Cu(111) crystal. The obtained results have been compared to previous gas phase spectra and single molecule Density Functional Theory (DFT) calculations to get insights into the possible modification of the molecular electronic structure in the film induced by the adsorption on a surface. Furthermore, NEXAFS measurements allowed characterizing the variation of the molecular arrangement with the film thickness and helped to clarify the substrate-molecule interaction.

  16. Elastohydrodynamic studies using thin film transducers

    NASA Astrophysics Data System (ADS)

    Safa, M. M. A.; MacPherson, P. B.

    1984-01-01

    Thin film microtransducers for application to the study of the variation of pressure, temperature, and oil film thickness in an elastohydrodynamically lubricated, nominal line contact were developed. Fabrication techniques were improved to enhance the useful life. Techniques to achieve higher resolution by reducing sensor size and improving the signal monitoring circuitry were developed. Material properties in thin film form used in fabricating the sensors were examined. Possible sources of errors in interpreting the results obtained from these devices were studied. Results under various operating conditions were compared with theoretical and experimental results, and reasonably good agreement is found.

  17. Ferrite thin films for microwave applications

    NASA Astrophysics Data System (ADS)

    Zaquine, I.; Benazizi, H.; Mage, J. C.

    1988-11-01

    This paper describes the preparation and the properties of thin (a few micron-thick) ferrite films for microwave applications. The films were deposited by RF sputtering from a single ferrite target on two different 4-in-thick substrates, silicon and alumina, both bare and metallized. The as-deposited films were amorphous, requiring careful annealing in oxygen atmosphere. The optimum annealing temperature was determined by obtaining the highest possible magnetization for each ferrite. The conditions of microwave measurements are described together with the results.

  18. Multilayer film structures for light sources

    NASA Astrophysics Data System (ADS)

    Aleksandrov, L. N.; Ivantsev, A. S.

    The possibility of using structures of multilayer semiconductor films to change the radiation spectrum of light sources is shown. The means of obtaining multilayer filters applied to lamp bulbs and their thermal stability are considered. The data on the influence of heating on the transmittance of the ZnS and MgF 2 films, on the shift of the transmission spectrum to short waves, and on dimness are pointed out. The kinetics of the film recrystallization are investigated and the increase of the thermal stability of multilayer structures by applying layers of Cr, SiO 2 and SnO 2 to the glass is shown.

  19. Laser deposition of bimetallic island films

    NASA Astrophysics Data System (ADS)

    Kucherik, A. O.; Arakelyan, S. M.; Kutrovskaya, S. V.; Osipov, A. V.; Istratov, A. V.; Vartanyan, T. A.; Itina, T. E.

    2016-08-01

    In this work the results of a bimetallic Au-Ag structure deposition from the colloidal system by nanosecond laser radiation are presented. The formation of the extended arrays of gold and silver nanoparticles with controlled morphology is examined. We report the results of formation bimetallic islands films with various electrical and optical properties. The changes in the optical properties of the obtained thin films are found to depend on their morphology.

  20. Rivulet dynamics at isothermal film flow

    NASA Astrophysics Data System (ADS)

    Bobylev, A. V.; Guzanov, V. V.; Kharlamov, S. M.; Kvon, A. Z.; Markovich, D. M.

    2017-08-01

    Averaged fields of thickness of an isothermal vertically flowing liquid film, obtained by the laserinduced fluorescence method, have been analyzed. The chosen minimum averaging time interval, at which the wave motion is completely averaged, allows one to observe rivulet dynamics in a transverse direction. It is found that short-lived rivulets, which are chains of no less than five to eight waves with similar transverse coordinates, are dominant structures on the film surface at Reynolds number Re > 50.

  1. Gamma irradiation effects in W films

    SciTech Connect

    Claro, Luiz H.; Santos, Ingrid A.; Silva, Cassia F.

    2013-05-06

    Using the van Der Pauw methodology, the surface resistivity of irradiated tungsten films deposited on Silicon substrate was measured. The films were exposed to {gamma} radiation using a isotopic {sup 60}Co source in three irradiation stages attaining 40.35 kGy in total dose. The obtained results for superficial resistivity display a time annealing features and their values are proportional to the total dose.

  2. Antimicrobial polymer films for food packaging

    NASA Astrophysics Data System (ADS)

    Concilio, S.; Piotto, S.; Sessa, L.; Iannelli, P.; Porta, A.; Calabrese, E. C.; Galdi, M. R.; Incarnato, L.

    2012-07-01

    New antimicrobial polymeric systems were realized introducing new antimicrobial azo compounds in PP and LDPE matrices. The polymeric materials containing different percentage of azo compounds were mold-casted and the obtained film were tested in vitro against Gram+ and Gram- bacteria and fungi. These results hold promise for the fabrication of bacteria-resistant polymer films by means of simple melt processing with antimicrobial azo-dyes.

  3. Organic Solar Cells Based on Electrodeposited Polyaniline Films

    NASA Astrophysics Data System (ADS)

    Inoue, Kei; Akiyama, Tsuyoshi; Suzuki, Atsushi; Oku, Takeo

    2012-04-01

    Polyaniline thin films as hole transporting layers were fabricated on transparent indium-tin-oxide electrodes by electrodeposition of aniline in an aqueous H2SO4 electrolyte solution. Emerald-green polyaniline films were obtained, which showed stable redox waves. A mixed solution of polythiophene and fullerene derivative was spin-coated onto the electrodeposited polyaniline film. After the modification of titanium oxide film on the surface of the polythiophene/fullerene layer, an aluminum electrode was fabricated by vacuum deposition. The obtained solar cells generated stable photocurrent and photovoltage under light illumination.

  4. Optical and scratch resistant properties of diamondlike carbon films deposited with single and dual ion beams

    NASA Technical Reports Server (NTRS)

    Kussmaul, Michael T.; Bogdanski, Michael S.; Banks, Bruce A.; Mirtich, Michael J.

    1993-01-01

    Amorphous diamondlike carbon (DLC) films were deposited using both single and dual ion beam techniques utilizing filament and hollow cathode ion sources. Continuous DLC films up to 3000 A thick were deposited on fused quartz plates. Ion beam process parameters were varied in an effort to create hard, clear films. Total DLC film absorption over visible wavelengths was obtained using a Perkin-Elmer spectrophotometer. An ellipsometer, with an Ar-He laser (wavelength 6328 A) was used to determine index of refraction for the DLC films. Scratch resistance and frictional and adherence properties were determined for select films. Applications for these films range from military to the ophthalmic industries.

  5. Optical and Scratch Resistant Properties of Diamondlike Carbon Films Deposited with Single and Dual Ion Beams

    NASA Technical Reports Server (NTRS)

    Kussmaul, Michael T.; Bogdanski, Michael S.; Banks, Bruce A.; Mirtich, Michael J.

    1993-01-01

    Amorphous diamond-like carbon (DLC) films were deposited using both single and dual ion beam techniques utilizing filament and hollow cathode ion sources. Continuous DLC films up to 3000 A thick were deposited on fused quartz plates. Ion beam process parameters were varied in an effort to create hard, clear films. Total DLC film absorption over visible wavelengths was obtained using a Perkin-Elmer spectrophotometer. An ellipsometer, with an Ar-He laser (wavelength 6328 A) was used to determine index of refraction for the DLC films. Scratch resistance, frictional, and adherence properties were determined for select films. Applications for these films range from military to the ophthalmic industries.

  6. Study of Critical Behaviour in Diluted Ferromagnetic:. Thin Films and Semi-Infinites Films

    NASA Astrophysics Data System (ADS)

    Masrour, R.; Hamedoun, M.; Benyoussef, A.

    By using the high-temperature series expansion technique, we have analyzed the phase transition and the critical phenomena of a ferromagnetic thin film and ferromagnetic semi-infinite film, through three models: Ising, XY and Heisenberg. The critical reduced temperature τC(v) is studied as a function of the thickness of the film. In the case of the magnetic film and semi-infinite film, on the simple cubic lattice and the face-centered cubic lattice, τC(v) is studied as a function of the exchange interactions in the bulk, and on the surface. A critical value of the surface exchange interaction in the film above which the surface and the interface magnetism appears is obtained. The dependence of the reduced critical temperature on the thickness of the film has been investigated. These shifts of the critical temperatures TC(L) from the bulk value can be described by a power law. The obtained values for the simple cubic lattice and face centered cubic ferromagnetic thin film are in qualitative accordance with the universality class hypothesis. The critical exponent associated with the magnetic susceptibility is studied as a function of interactions. In a defined range of the exchange interactions, the obtained values for Heisenberg, XY and Ising models, for simple cubic thin film are comparable to the universal ones and are independent of the film thickness. The asymmetry of the structure and the competition of the effects of the exchange coupling, are important for the magnetic properties of the system. A critical value of the surface exchange interaction above which the surface magnetism appears is obtained. For the dependence of the critical parameter of surface reduced coupling R2C as a function of the dilution x and the ratio of the exchange interaction between the surface and nearest neighbour layer to the bulk one R1 for the three studied models has been investigated. The magnetic phase diagrams are obtained for two structures. The percolation threshold is

  7. Functional profile coatings and film stress

    NASA Astrophysics Data System (ADS)

    Liu, Chian; Conley, R.; Macrander, A. T.

    2004-07-01

    In recent years, we have developed a profile-coating technique to obtain functional thickness-profiled thin films and multilayers. This technique uses linear motion of the substrate in a dc magnetron sputter system and a contoured mask to obtain the desired profile perpendicular to the substrate-moving direction. The shape of the contour is determined according to the desired profile and knowledge of the film-thickness distribution at the substrate level. Applications of this technique include laterally graded multilayers and elliptical x-ray Kirkpatrick-Baez (KB) mirrors. An elliptical shape is essential for aberration-free optics. The use of profile coating to make x-ray-quality elliptical KB mirrors overcomes the obstacle of polishing asymmetrical mirror surfaces and provides the x-ray community with a practical way to obtain monolithic KB mirrors for microfocusing. Previously, we have used gold as a coating material and cylindrical Si mirrors as substrates to obtain elliptical KB mirrors. More recently, we have used flat Si substrates to fabricate elliptical KB mirrors. Substantially thicker and steeper gradients of Au films are needed to obtain an elliptical profile from a flat substrate. The Au films may relax to droplets when the stress in the film is too large. The challenges and solutions for this problem will be discussed. .

  8. Formation of crystalline heteroepitaxial SiC films on Si by carbonization of polyimide Langmuir-Blodgett films

    NASA Astrophysics Data System (ADS)

    Luchinin, Viktor V.; Goloudina, Svetlana I.; Pasyuta, Vyacheslav M.; Panov, Mikhail F.; Smirnov, Alexander N.; Kirilenko, Demid A.; Semenova, Tatyana F.; Sklizkova, Valentina P.; Gofman, Iosif V.; Svetlichnyi, Valentin M.; Kudryavtsev, Vladislav V.

    2017-06-01

    High-quality crystalline nano-thin SiC films on Si substrates were prepared by carbonization of polyimide (PI) Langmuir-Blodgett (LB) films. The obtained films were characterized by Fourier transform-infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, Raman spectroscopy, transmission electon microscopy (TEM), transmission electron diffraction (TED), and scanning electron microscopy (SEM). We demonstrated that the carbonization of a PI film on a Si substrate at 1000 °C leads to the formation of a carbon film and SiC nanocrystals on the Si substrate. It was found that five planes in the 3C-SiC(111) film are aligned with four Si(111) planes. As a result of repeated annealing of PI films containing 121 layers at 1200 °C crystalline SiC films were formed on the Si substrate. It was shown that the SiC films (35 nm) grown on Si(111) at 1200 °C have a mainly cubic 3C-SiC structure with small amount of hexagonal polytypes. Only 3C-SiC films (30 nm) were formed on the Si(100) substrate at the same temperature. It was shown that the SiC films (30-35 nm) can cover the voids with size up to 10 µm in the Si substrate. The current-voltage (I-V) characteristics of the n-Si/n-SiC heterostructure were obtained by conductive atomic force microscopy.

  9. Effect of Self-Assembled Monolayer Film Order on Nanofriction

    SciTech Connect

    Sambasivan,S.; Shieh, S.; Fischer, D.; Hsu, S.

    2006-01-01

    Self-assembled monolayers have increasingly been explored as potential protective films in devices against friction and adhesion. However, detailed characterization of the monolayer film structure is difficult. This article utilizes a combination of near edge x-ray absorption fine structure (NEXAFS) spectroscopy and Fourier transform infrared (FTIR) spectroscopy to determine the film structure in order to explain the observed nanofriction measurement results. A series of n-alkyltrichlorosilane self-assembled monolayer films with various chain lengths (C5-C30) was prepared on silicon (100) surfaces. Nanofriction measurements were conducted using an atomic force microscope. Results showed that the lowest friction was obtained with a C12 film with higher friction values observed for C5 and C30 films. To explain these observations, the x-ray absorption technique NEXAFS was used to quantitatively measure the surface molecular orientation (order) of these films. It was observed that C12, C16, and C18 films were highly ordered with a molecular orientation of the carbon backbone nearly perpendicular to the surface. C5 and C30 films were less oriented and C10 film showed partial orientation. FTIR spectra suggested that these films possessed different degrees of order. This combination of molecular orientation and order supports and confirms that nanofriction results were heavily influenced by the order and structure of these films.

  10. Effect of Substrates on Film Hardness Measurements of Nanometer Thick Amorphous Carbon Films

    NASA Astrophysics Data System (ADS)

    Akasaka, Hiroki; Ito, Hiroki; Nakano, Masayuki; Ohshio, Shigeo; Saitoh, Hidetoshi

    Amorphous carbon film (a-C:H) applications, such as hard disks, require films with nanometer thicknesses. In an indentation test, the obtained hardness values of these films are affected by substrates. On the indentation tests, we studied the effect of substrate hardness on films less than 200 nm in thickness. a-C:H and Si doped a-C:H (a-C:Si:H) films were deposited by electron cyclotron resonance plasma chemical vapor deposition onto aluminum (Al) and silicon (Si) substrates. The film thicknesses were approximately 140 nm. The hardnesses of the a-C:H film and substrates were obtained using a high-resolution indentation tester (pico-dentor) with a Vickers tip whose depth resolution was 0.04 nm. Maximum indentation loads were varied from 0.01 to 0.5 mN. The Martens hardnesses of films on the Al and Si substrates were 600 and 7000 N/mm2, respectively. On the a-C:Si:H film deposited on the Al substrate, the hardnesses increased from 1600 to 3900 N/mm2 with decreasing indentation load. The hardnesses of the films deposited on the Si substrate decreased from 5300 to 3500 N/mm2 when the maximum indentation loads were reduced. The effect of the substrates increased with the maximum load increasing. From these findings, the actual hardness value was determined to be 3600 N/mm2. These results indicate that the high-resolution indentation test achieved hardness estimations for nanometer-thick films with certain hardnesses.

  11. SOFIA Observatory Obtains 'First Light' Images

    NASA Image and Video Library

    NASA's Stratospheric Observatory for Infrared Astronomy, or SOFIA, successfully obtained its "First Light"" images during an overnight flight May 26. Scientists are now processing the data gathered...

  12. 40 CFR 35.6310 - Obtaining equipment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... STATE AND LOCAL ASSISTANCE Cooperative Agreements and Superfund State Contracts for Superfund Response Actions Personal Property Requirements Under A Cooperative Agreement § 35.6310 Obtaining equipment....

  13. 40 CFR 35.6305 - Obtaining supplies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... STATE AND LOCAL ASSISTANCE Cooperative Agreements and Superfund State Contracts for Superfund Response Actions Personal Property Requirements Under A Cooperative Agreement § 35.6305 Obtaining supplies....

  14. Spin Coated Nano Scale PMMA Films for Organic Thin Film Transistors

    NASA Astrophysics Data System (ADS)

    Shekar, B. Chandar; Sathish, S.; Sengoden, R.

    Nano scale poly methyl methacrylate (PMMA) films are prepared by spin coating the solution of PMMA on to p-Si substrate. The thickness of the films coated is measured by Ellipsometry. The SA-XRD spectrum of the as grown and annealed films indicated the amorphous nature. The SEM analysis revealed no pinholes, pits and dendritic features on the surface. Both as grown and annealed films indicated smooth surface and amorphous structure. The capacitance-voltage (C-V) behaviour of the metal-insulator-semiconductor (MIS) structure with Al/PMMA/p-Si has been studied. The C-V behaviour carried out for various frequencies (f) ranging from 20 kHz to 1 MHz and for a bias voltage range of -20 V to +20 V. Both as grown and annealed films showed a small flat band voltage (VFB) shift towards the negative voltage. The small shift in the VFB observed may be due to charge traps and de-traps. The obtained C-V behaviour for as grown and annealed films indicated that as grown PMMA nano scale thin films do not have many defects such as voids and inhomogeneity etc. The observed C-V behavior, a very low shift in the flat band voltage (VFB 0); reasonably higher dielectric constant values; thermal stability up to 2800C; amorphous and smooth surface implies that nano scale thin PMMA film coated by spin coating could be used as an efficient dielectric layer in field effect organic thin film transistors (OTFTs).

  15. Solid polymeric electrolytes obtained from modified natural polymers

    NASA Astrophysics Data System (ADS)

    Pawlicka, Agnieszka; Machado, G. O.; Guimaraes, K. V.; Dragunski, Douglas C.

    2003-10-01

    Polysaccharides like starch and cellulose derivatives, hydroxyethylcellulose (HEC) or hydroxypropylcellulose (HPC) were modified to obtain solid polymeric electrolytes. The chemical modifications were performed by the grafting of polymers with poly(ethylene oxide) mono and diisocyanates or JEFFAMINE (Shiff base). The physical modifications were made by the plasticization process of starch and cellulose derivatives with glycerol and ethylene glycol. All the samples obtained from polysaccharides were characterized by X-ray, thermal analysis (DSC) and impedance spectroscopy. The plasticized samples showed low glass transition temperatures (Tg); for HEC the value was about -60°C and for starch it was about -30°C. Tg values for grafted samples were of about -58°C for starch and -7°C for HPC. The low Tg values obtained are important to ensure good ionic conductivity that reached the values of about 10-5 Scm-1 for plasticized samples and 10-6 Scm-1 for grafted ones at room temperature. The good film forming and ionic conductivity properties of the samples of HEC, HPC and starch are very interesting candidates to be used as solid polymer electrolytes.

  16. 33 CFR 118.20 - Obtaining information.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Obtaining information. 118.20 Section 118.20 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.20 Obtaining information. Persons desiring information concerning the...

  17. 33 CFR 118.20 - Obtaining information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Obtaining information. 118.20 Section 118.20 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.20 Obtaining information. Persons desiring information concerning the...

  18. 33 CFR 118.20 - Obtaining information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Obtaining information. 118.20 Section 118.20 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.20 Obtaining information. Persons desiring information concerning the...

  19. 33 CFR 118.20 - Obtaining information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Obtaining information. 118.20 Section 118.20 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.20 Obtaining information. Persons desiring information concerning the...

  20. 33 CFR 118.20 - Obtaining information.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Obtaining information. 118.20 Section 118.20 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LIGHTING AND OTHER SIGNALS § 118.20 Obtaining information. Persons desiring information concerning the...

  1. 42 CFR 442.101 - Obtaining certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... section states the requirements for obtaining notice of an ICF/MR's certification before a Medicaid agency... Secretary for an ICF/MR located on an Indian reservation. (c) The agency must obtain notice of certification... provisions pertains to the ICF/MR: (1) An ICF/MR meets the conditions of participation set forth in subpart I...

  2. Astrophysical Reaction Rates Obtained By Indirect Techniques

    SciTech Connect

    Tribble, R. E.; Al-Abdullah, T.; Alharbi, A.; Banu, A.; Chen, X.; Clark, H. L.; Fu, C.; Gagliardi, C. A.; Hardy, J. C.; Iacob, V. E.; Lui, Y.-W.; McCleskey, M.; Mukhamedzhanov, A.; Nica, N.; Park, H. I.; Roeder, B.; Simmons, E.; Tabacaru, G.; Tokimoto, Y.; Trache, L.

    2010-08-12

    Indirect techniques have been used to obtain information about reaction rates for several proton capture reactions that occur on short-lived nuclei. The techniques used to carry out the measurements are reviewed and the results obtained are presented. Also future prospects for further measurements with a new facility, T-REX are discussed.

  3. Ready Reference. How To Obtain an ISBN; How To Obtain an ISSN; How To Obtain an SAN.

    ERIC Educational Resources Information Center

    Koltay, Emery

    2003-01-01

    These three articles describe ISBNs (International Standard Book Numbers); ISSNs (International Standard Serial Numbers); and SANs (Standard Address Numbers), for organizations served by the book industry; and explains how to apply to obtain the appropriate numbers. (LRW)

  4. Near-field radiative heat transfer between metamaterial thin films.

    PubMed

    Basu, Soumyadipta; Francoeur, Mathieu

    2014-03-01

    We investigate near-field radiative heat transfer between two thin films made of metamaterials. The impact of film thickness on magnetic and electric surface polaritons (ESPs) is analyzed. It is found that the strength as well as the location of magnetic resonance does not change with film thickness until the film behaves as semi-infinite for the dielectric function chosen in this study. When the film is thinner than vacuum gap, both electric and magnetic polaritons contribute evenly to near-field radiative heat transfer. At larger film thicknesses, ESPs dominate heat transfer due to excitation of a larger number of modes. Results obtained from this study will facilitate applications of metamaterials as thin-film coatings for energy systems.

  5. Complex film of chitosan and carboxymethyl cellulose nanofibers.

    PubMed

    Kawasaki, Takuma; Nakaji-Hirabayashi, Tadashi; Masuyama, Kazuhira; Fujita, Satoshi; Kitano, Hiromi

    2016-03-01

    A polymer film composed of a mixture of chitosan (Ch) and carboxymethyl cellulose sodium salt (CMC) nanofibers was deposited on a glass surface. The thin film of the Ch-CMC mixture obtained was stable, and fibroblast adhesion to the film was lowest when the weight ratio of Ch to CMC was 4:6. The ζ-potential and contact angle of the mixture film indicated that a polyion complex of Ch and CMC was formed. The mechanical strength of the film composed of Ch-CMC nanofiber complexes was much higher than that of the film composed of Ch-water-soluble CMC complexes (non-nanofiber), likely because the entanglement of nanofibers was enhanced by electrostatic attractions. These results indicate that the charge-neutralized nanofiber film was highly effective in suppressing cell adhesion and therefore is a promising material for biomedical applications.

  6. Numerical characterization and modeling of adiabatic slot film cooling

    NASA Astrophysics Data System (ADS)

    Voegele, Andrew

    Film cooling is a technique used to protect critical surfaces in combustors, thrust chambers, turbines and nozzles from hot, chemically reacting gases. Accurately predicting the film's performance is especially challenging in the vicinity of the wall and the film injection plane due to the complex interactions of two highly turbulent, shearing, boundary layer flows. Properly characterizing the streams at the inlet of a numerical simulation and the choice of turbulence model are crucial to accurately predicting the decay of the film. To address these issues, this study employs a RANS solver that is used to model a film cooled wall. Menter's baseline model, and shear-stress transport model and the Spalart-Allmaras model are employed to determine the effect on film cooling predictions. Several methods for prescribing the inlet planes are explored. These numerical studies are compared with experimental data obtained in a UMD film cooling wind tunnel.

  7. Immobilization of lysozyme on polyvinylalcohol films for active packaging applications.

    PubMed

    Conte, A; Buonocore, G G; Bevilacqua, A; Sinigaglia, M; Del Nobile, M A

    2006-04-01

    A new technique for the immobilization of lysozyme onto the surface of polyvinylalcohol films is presented. The active compound was sprayed along with a suitable bonding agent onto the surface of the cross-linked polymeric matrix. Active compound release tests determined the amount of lysozyme immobilized on the film surface. With the use of Micrococcus lysodeikticus, the antimicrobial activity of the films was determined and the results correlated with the amount of immobilized lysozyme. This new technique was effective for immobilizing the enzyme, and the developed films were active against the test microorganism. Results were compared with those obtained with a different immobilizing technique, in which the active compound was bound into the bulk of the polymeric film. As expected, the surface-immobilized lysozyme films have a higher antimicrobial activity than bulk-bound films.

  8. Confocal micro-Raman spectroscopy of black soap films

    NASA Astrophysics Data System (ADS)

    Lecourt, B.; Capelle, F.; Adamietz, F.; Malaplate, A.; Blaudez, D.; Kellay, H.; Turlet, J. M.

    1998-01-01

    Black soap films from aqueous solutions of sodium dodecyl sulphate are studied by micro-Raman confocal spectroscopy. At the end of the draining process films of different thicknesses are obtained depending on the experimental conditions: Working in a closed humidified chamber leads to common black films while, under evaporation or in the presence of electrolyte, Newton black films are observed. From the Raman spectra of these films, quantitative information is deduced about the conformational and lateral order of the aliphatic surfactant chains, as well as the thickness of the residual water layer. More accurate measurements of the thickness of these ultimate films have been carried out by transmission ellipsometry and their effective refractive index measured by Brewster angle reflectivity. The thinner films present higher molecular organization and their aqueous core exhibits unusual spectral features.

  9. 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.

  10. SnS2 Thin Film Deposition by Spray Pyrolysis

    NASA Astrophysics Data System (ADS)

    Jaber, Abdallah Yahia; Alamri, Saleh Noaiman; Aida, Mohammed Salah

    2012-06-01

    Tin disulfide (SnS2) thin films have been synthesized using a simplified spray pyrolysis technique using a perfume atomizer. The films were deposited using two different solutions prepared by the dilution of SnCl2 and thiourea in distilled water and in methanol. The obtained films have a microcrystalline structure. The film deposited using methanol as the solvent is nearly stochiometric SnS2 with a spinel phase having a (001) preferential orientation. The film prepared with an aqueous solution is Sn-rich. Scanning electronic microscopy (SEM) images reveal that the film deposited with the aqueous solution is rough and is formed with large wires. However, the film deposited with methanol is dense and smooth. Conductivity measurements indicate that the aqueous solution leads to an n-type semiconductor, while methanol leads to a p-type semiconductor.

  11. Lead Iodide Thin Film Crystallization Control for High-Performance and Stable Solution-Processed Perovskite Solar Cells.

    PubMed

    Yang, Lijun; Wang, Jingchuan; Leung, Wallace Woon-Fong

    2015-07-15

    PbI2 thin film crystallization control is a prerequisite of high-quality perovskite thin film for sequentially solution-processed perovskite solar cells. An efficient and simple method has been developed by adding HCl to improve perovskite thin film quality, and an efficiency of 15.2% is obtained. This approach improves coverage, uniformity, and stability of pervoskite thin film.

  12. Magnetostatic interactions in films for perpendicular recording media

    NASA Astrophysics Data System (ADS)

    Bottoni, G.; Candolfo, D.; Cecchetti, A.

    1999-04-01

    The magnetostatic interactions in CoCr films for perpendicular recording are studied, based on the measurement of ordinary magnetization curves. The method used does not need the evaluation of the remanent magnetization curves, which is difficult to obtain in these media because of the presence of demagnetizing field in the anisotropy direction. The obtained interaction effects are related with the film thickness, Cr content, the presence of a Fe81Ni19 underlayer, and the magnetic properties of the recording media. The interactions are strong in films with large thickness and they are weak when the thickness is small and even weaker in double layer FeNi/CoCr films. This result is correlated with the magnetization reversal mode, which evolves towards incoherent mechanisms when the film thickness decreases and even more in double layers, as a consequence of the greater dispersion in the vertical columnar structure of the CoCr films.

  13. Acetylated rice starches films with different levels of amylose: Mechanical, water vapor barrier, thermal, and biodegradability properties.

    PubMed

    Colussi, Rosana; Pinto, Vânia Zanella; El Halal, Shanise Lisie Mello; Biduski, Bárbara; Prietto, Luciana; Castilhos, Danilo Dufech; Zavareze, Elessandra da Rosa; Dias, Alvaro Renato Guerra

    2017-04-15

    Biodegradable films from native or acetylated starches with different amylose levels were prepared. The films were characterized according to the mechanical, water vapor barrier, thermal, and biodegradability properties. The films from acetylated high amylose starches had higher moisture content and water solubility than the native high amylose starch film. However, the acetylation did not affect acid solubility of the films, regardless of the amylose content. Films made from high and medium amylose rice starches were obtained; however low amylose rice starches, whether native or acetylated, did not form films with desirable characteristics. The acetylation decreased the tensile strength and increased the elongation of the films. The acetylated starch-based films had a lower decomposition temperature and higher thermal stability than native starch films. Acetylated starches films exhibited more rapid degradation as compared with the native starches films.

  14. The Educational Film Industry

    ERIC Educational Resources Information Center

    Tortora, Vincent R.; Schillaci, Peter

    1975-01-01

    Increased dialog is needed among educational film producers, distributors, and consumers in order to be sure that what is being produced meets educators' needs and also to help solve the financial problems of the film industry. (LS)

  15. The Educational Film Industry

    ERIC Educational Resources Information Center

    Tortora, Vincent R.; Schillaci, Peter

    1975-01-01

    Increased dialog is needed among educational film producers, distributors, and consumers in order to be sure that what is being produced meets educators' needs and also to help solve the financial problems of the film industry. (LS)

  16. Thin-Film Selective Emitter

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Lowe, Roland A.

    1993-01-01

    Direct conversion of thermal energy into electrical energy using a photovoltaic cell is called thermophotovoltaic energy conversion. One way to make this an efficient process is to have the thermal energy source be an efficient selective emitter of radiation. The emission must be near the band-gap energy of the photovoltaic cell. One possible method to achieve an efficient selective emitter is the use of a thin film of rare-earth oxides. The determination of the efficiency of such an emitter requires analysis of the spectral emittance of the thin film including scattering and reflectance at the vacuum-film and film-substrate interfaces. Emitter efficiencies (power emitted in emission band/total emitted power) in the range 0.35-0.7 are predicted. There is an optimum optical depth to obtain maximum efficiency. High emitter efficiencies are attained only for low (less than 0.05) substrate emittance values, both with and without scattering. The low substrate emittance required for high efficiency limits the choice of substrate materials to highly reflective metals or high-transmission materials such as sapphire.

  17. Films and Video: Literature Film Catalog.

    ERIC Educational Resources Information Center

    Southern Illinois Univ., Carbondale.

    Intended for teachers of literature, this 37-page film catalog lists a wide selection of film adaptations of literary works and literary topics that are available for rental through the Learning Resources Services of the Southern Illinois University at Carbondale. The catalog is organized both by title and author. Entries include plays, short…

  18. Film as Film; Understanding and Judging Movies.

    ERIC Educational Resources Information Center

    Perkins, V. F.

    The criteria for judging movies which are presented here are based on the belief that film criticism becomes rational, if not "objective", when it displays and inspects the nature of its evidence and the bases of its arguments. The author dissents from the view of early film theorists that montage is the essence of cinema, and that cinema is to be…

  19. Film as Film; Understanding and Judging Movies.

    ERIC Educational Resources Information Center

    Perkins, V. F.

    The criteria for judging movies which are presented here are based on the belief that film criticism becomes rational, if not "objective", when it displays and inspects the nature of its evidence and the bases of its arguments. The author dissents from the view of early film theorists that montage is the essence of cinema, and that cinema is to be…

  20. Mechanics of Thin Films

    DTIC Science & Technology

    1992-02-06

    32 (1991). INTRODUCTION Many technological areas currently use designs that rely on thin films for a variety of effects that include mechanical...film thickness, d is the width of the columnar grains, and Q is the atomic volume. The current film thickness h0 increases in proportion to the film...temperature and on the level of the far field uniform stress (121. h careful examination of these assumptions is currently under way. This work has

  1. Exploring the Film.

    ERIC Educational Resources Information Center

    Kuhns, William; Stanley, Robert

    The purpose of film study is defined here in the words of D. W. Griffiths: "My goal is above all to make you see." This book is intended to be used as a text in a film study course. It traces the development of films from a scientific curiosity through silent films to modern wide screen productions. A comic strip is used to demonstrate the effect…

  2. 25 CFR 162.539 - Must I obtain a WEEL before obtaining a WSR lease?

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... AND PERMITS Wind and Solar Resource Leases Wsr Leases § 162.539 Must I obtain a WEEL before obtaining... direct result of energy resource information gathered from a WEEL activity, obtaining a WEEL is not a...

  3. 25 CFR 162.539 - Must I obtain a WEEL before obtaining a WSR lease?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... AND PERMITS Wind and Solar Resource Leases Wsr Leases § 162.539 Must I obtain a WEEL before obtaining... direct result of energy resource information gathered from a WEEL activity, obtaining a WEEL is not a...

  4. Polyester fabric coated with Ag/ZnO composite film by magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Yuan, Xiaohong; Xu, Wenzheng; Huang, Fenglin; Chen, Dongsheng; Wei, Qufu

    2016-12-01

    Ag/ZnO composite film was successfully deposited on polyester fabric by using direct current (DC) magnetron sputtering and radio frequency (RF) magnetron reaction sputtering techniques with pure silver (Ag) and zinc (Zn) targets. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) were used to examine the deposited film on the fabric. It was found that the zinc film coated on Ag film before RF reactive sputtering could protect the silver film from oxidation. Anti-ultraviolet property and antistatic property of the coated samples using different magnetron sputtering methods were also investigated. The experimental results showed that Ag film was oxidized into in Ag2O film in high vacuum oxygen environment. The deposition of Zn film on the surface of the fabric coated with Ag film before RF reactive sputtering, could successfully obtained Ag/ZnO composite film, and also generated structural color on the polyester fabric.

  5. Influence of annealing on optical and photovoltaic properties of nanostructured TiO2 films

    NASA Astrophysics Data System (ADS)

    Serikov, T. M.; Ibrayev, N. Kh; Smagulov, Zh Kh; Kuterbekov, К. А.

    2017-01-01

    Spectral and kinetic characteristics of the photoluminescence of TiO2 films obtained from TiO2 nanoparticles and nanotubes were studied. Luminescence spectra typical for the TiO2 with anatase structure were observed under UV excitation of the films. Heat treatment of the films at T=1273 K leads to a long-wavelength shift of the photoluminescence band with maximum at 850 nm, which corresponds to the rutile structure. The luminescence duration of rutile films is longer than the luminescence duration of the anatase films as for nanoparticles and for nanotubes. The photovoltaic properties of TiO2 films with different structures were investigated. It was established that anatase structured films have a higher photocurrent than the rutile structured film. By impedance spectroscopy method it was found that the electron transport resistance in the nanotube films is higher but the recombination rate is lower than in the TiO2 nanoparticle films.

  6. Coercivity of granular ferromagnetic films and related multilayer structures

    NASA Astrophysics Data System (ADS)

    Vdovichev, S. N.; Gribkov, B. A.; Klimov, A. Yu.; Rogov, V. V.

    2008-08-01

    Thin films of a granular ferromagnet (GF) based on phase-separating cobalt-copper solid solution have been obtained and their magnetic properties have been studied. It is established that the use of such GF films as sublayers provides a significant increase in the coercivity of thin cobalt films. Based on the GF cobalt-copper sublayers, multilayer structures with different magnetization reversal fields of component layers have been manufactured.

  7. Preparation and characterization of silk fibroin/HPMC blend film

    SciTech Connect

    Shetty, G. Rajesha; Kumar, R. Madhu; Rao, B. Lakshmeesha; Asha, S.; Sangappa

    2015-06-24

    In this work, the structural and mechanical stability of silk fibroin/Hydroxypropylmethyl cellulose (SF-HPMC) blend films were characterized by X-ray diffraction (XRD) and Universal Testing Machine (UTM). The results indicate that with the introduction of HPMC, the interactions between SF and HPMC results in improved crystallite size and increase in mechanical properties. The blend film obtained is more flexible compared to pure SF film.

  8. Microporous polymer films and methods of their production

    DOEpatents

    Aubert, James H.

    1995-01-01

    A process for producing thin microporous polymeric films for a variety of uses. The process utilizes a dense gas (liquified gas or supercritical fluid) selected to combine with a solvent-containing polymeric film so that the solvent is dissolved in the dense gas, the polymer is substantially insoluble in the dense gas, and two phases are formed. A microporous film is obtained by removal of a dense gas-solvent phase.

  9. Microporous polymer films and methods of their production

    DOEpatents

    Aubert, J.H.

    1995-06-06

    A process is described for producing thin microporous polymeric films for a variety of uses. The process utilizes a dense gas (liquefied gas or supercritical fluid) selected to combine with a solvent-containing polymeric film so that the solvent is dissolved in the dense gas, the polymer is substantially insoluble in the dense gas, and two phases are formed. A microporous film is obtained by removal of a dense gas-solvent phase. 9 figs.

  10. Introduction to Film Making.

    ERIC Educational Resources Information Center

    Davis, Robert E.

    This booklet is intended for teachers who are now teaching units in film production as part of a program in communication or who wish to begin work with filmmaking in such a program. The first section is intended to serve as a brief introduction to film theory, while a major portion of the rest of the booklet is devoted to film projects which may…

  11. Mental Retardation Film List.

    ERIC Educational Resources Information Center

    National Library of Medicine (DHEW), Bethesda, MD.

    A list of films on mental retardation includes titles, publication information, physical descriptions, language revisions when other than English, series reference, technical description of film content, sale source, and distributor. Films intended for the general public are grouped under the heading Nonprofessional; others are listed as…

  12. 8MM Film Directory.

    ERIC Educational Resources Information Center

    Kone, Grace Ann, Comp.

    All 8mm films in general distribution in the United States, regardless of length or subject, are listed in this directory: Standard or Super 8, silent or sound, cartridge or reel-to-reel. Indexed alphabetically and by the Dewey Decimal System, films and film series are entered under the headings of Arts, Education, Fiction, Language, Recreation,…

  13. Health Careers Film Guide.

    ERIC Educational Resources Information Center

    National Institutes of Health (DHEW), Bethesda, MD. Bureau of Health Manpower Education.

    This document, which represents a survey of the entire health career film field, was designed to provide information for people interested in a health career. The guide indicates that a major criteria for film selection was recency; however, some older films that give a fairly accurate image of a profession were included, with some emphasis given…

  14. Marine Science Film Catalogue.

    ERIC Educational Resources Information Center

    Chapman, Frank L.

    Forty-eight motion picture films and filmstrips in the field of marine science are catalogued in this booklet. Following the alphabetical index, one page is devoted to each film indicating its type, producer, recommended grade level, running time, and presence of color and/or sound. A summary of film content, possible uses, and outstanding…

  15. The Language of Film.

    ERIC Educational Resources Information Center

    Whitaker, Rod

    This book, designed for the film maker, critic, and serious filmgoer, explores elements of filmic expression from the creative and perceptual points of view. Chapters (1) trace the linguistic and mechanical development of film, (2) discuss the contributions of image and sound to film content, (3) suggest the contributions of editing and montage,…

  16. Analysis of Film.

    ERIC Educational Resources Information Center

    Stupp, Vicki O'Donnell

    In order to understand the communicative interaction of film, it is necessary to carefully analyze the special qualities of film as a visual medium, to understand the elements of audience identification with what happens in the film, and to interpret the use of symbolism that enables an audience to derive meaning from it. Among the special…

  17. Getting into Film.

    ERIC Educational Resources Information Center

    London, Mel

    This book describes the various aspects of the film industry and the many jobs related to filmmaking, stressing that no "formula" exists for finding a successful career in the film industry. Chapters provide information on production, writing for film, cinematography, editing, music, sound, animation and graphics, acting and modeling, the "unsung…

  18. Australian Film Studies.

    ERIC Educational Resources Information Center

    Breen, Myles P.

    Although Australia had a vigorous film industry in the silent film era, it was stifled in the 1930s when United States and British interests bought up the Australian distribution channels and closed down the indigenous industry. However, the industry and film study have undergone a renaissance since the advent of the Labor government in 1972,…

  19. Getting into Film.

    ERIC Educational Resources Information Center

    London, Mel

    This book describes the various aspects of the film industry and the many jobs related to filmmaking, stressing that no "formula" exists for finding a successful career in the film industry. Chapters provide information on production, writing for film, cinematography, editing, music, sound, animation and graphics, acting and modeling, the "unsung…

  20. The Language of Film.

    ERIC Educational Resources Information Center

    Whitaker, Rod

    This book, designed for the film maker, critic, and serious filmgoer, explores elements of filmic expression from the creative and perceptual points of view. Chapters (1) trace the linguistic and mechanical development of film, (2) discuss the contributions of image and sound to film content, (3) suggest the contributions of editing and montage,…

  1. Thick Film Interference.

    ERIC Educational Resources Information Center

    Trefil, James

    1983-01-01

    Discusses why interference effects cannot be seen with a thick film, starting with a review of the origin of interference patterns in thin films. Considers properties of materials in films, properties of the light source, and the nature of light. (JN)

  2. Thick Film Interference.

    ERIC Educational Resources Information Center

    Trefil, James

    1983-01-01

    Discusses why interference effects cannot be seen with a thick film, starting with a review of the origin of interference patterns in thin films. Considers properties of materials in films, properties of the light source, and the nature of light. (JN)

  3. Australian Film Studies.

    ERIC Educational Resources Information Center

    Breen, Myles P.

    Although Australia had a vigorous film industry in the silent film era, it was stifled in the 1930s when United States and British interests bought up the Australian distribution channels and closed down the indigenous industry. However, the industry and film study have undergone a renaissance since the advent of the Labor government in 1972,…

  4. 99 Films on Drugs.

    ERIC Educational Resources Information Center

    Weber, David O., Ed.

    This catalog describes and evaluates 16-millimeter films about various aspects of drug use. Among the subjects covered by the 99 films are the composition and effects of different drugs, reasons why people use drugs, life in the drug culture, the problem of law enforcement, and various means of dealing with drug users. Each film is synopsized. Two…

  5. Focus on Shakespearean Films.

    ERIC Educational Resources Information Center

    Eckert, Charles W., Ed.

    This is an anthology of reviews and critical pieces of the significant and available Shakespearean films made between 1935 and 1966. Included are three general essays on Shakespearean film by Ian Johnson, Henri Lemaitre, and Geoffrey Reeves. The specific films and their reviewers are: A Midsummer's Night Dream (1935) Allardyce Nicoll and Richard…

  6. Playing With Film.

    ERIC Educational Resources Information Center

    Gaffney, Maureen, Ed.

    1980-01-01

    Designed for media specialists and educators, this issue includes five articles on innovative museum film programs. The first article describes a successful film program conducted at the Staten Island Children's Museum. The second article describes inventive children's programs at the Delaware Museum of Art. The programs use films and activities…

  7. Focus on Shakespearean Films.

    ERIC Educational Resources Information Center

    Eckert, Charles W., Ed.

    This is an anthology of reviews and critical pieces of the significant and available Shakespearean films made between 1935 and 1966. Included are three general essays on Shakespearean film by Ian Johnson, Henri Lemaitre, and Geoffrey Reeves. The specific films and their reviewers are: A Midsummer's Night Dream (1935) Allardyce Nicoll and Richard…

  8. 48 CFR 53.107 - Obtaining forms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Government Printing Office (GPO). (b) Contractors and other parties may obtain standard and optional forms from the Superintendent of Documents, GPO, Washington, DC 20402. Standard and optional forms not...

  9. 48 CFR 53.107 - Obtaining forms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Government Printing Office (GPO). (b) Contractors and other parties may obtain standard and optional forms from the Superintendent of Documents, GPO, Washington, DC 20402. Standard and optional forms not...

  10. 48 CFR 53.107 - Obtaining forms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Government Printing Office (GPO). (b) Contractors and other parties may obtain standard and optional forms from the Superintendent of Documents, GPO, Washington, DC 20402. Standard and optional forms not...

  11. 48 CFR 53.107 - Obtaining forms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Government Printing Office (GPO). (b) Contractors and other parties may obtain standard and optional forms from the Superintendent of Documents, GPO, Washington, DC 20402. Standard and optional forms not...

  12. Treatment of biomass to obtain ethanol

    DOEpatents

    Dunson, Jr., James B.; Elander, Richard T [Evergreen, CO; Tucker, III, Melvin P.; Hennessey, Susan Marie [Avondale, PA

    2011-08-16

    Ethanol was produced using biocatalysts that are able to ferment sugars derived from treated biomass. Sugars were obtained by pretreating biomass under conditions of high solids and low ammonia concentration, followed by saccharification.

  13. 47 CFR 54.615 - Obtaining services.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... provided under § 54.621, that the requester cannot obtain toll-free access to an Internet service provider... thing of value; (6) If the service or services are being purchased as part of an aggregated purchase...

  14. 47 CFR 54.615 - Obtaining services.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... provided under § 54.621, that the requester cannot obtain toll-free access to an Internet service provider... thing of value; (6) If the service or services are being purchased as part of an aggregated...

  15. 47 CFR 54.615 - Obtaining services.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... provided under § 54.621, that the requester cannot obtain toll-free access to an Internet service provider... thing of value; (6) If the service or services are being purchased as part of an aggregated purchase...

  16. Mass culture of photobacteria to obtain luciferase

    NASA Technical Reports Server (NTRS)

    Chappelle, E. W.; Picciolo, G. L.; Rich, E., Jr.

    1969-01-01

    Inoculating preheated trays containing nutrient agar with photobacteria provides a means for mass culture of aerobic microorganisms in order to obtain large quantities of luciferase. To determine optimum harvest time, growth can be monitored by automated light-detection instrumentation.

  17. Electrical properties of transparent conductive ATO coatings obtained by spray pyrolysis

    NASA Astrophysics Data System (ADS)

    Zinchenko, T. O.; Kondrashin, V. I.; Pecherskaya, E. A.; Kozlyakov, A. S.; Nikolaev, K. O.; Shepeleva, J. V.

    2017-08-01

    Transparent conductive coatings based on thin films of metal oxides have been widely spread in various optoelectronic devices and appliances. It is necessary to determine the influence of preparation conditions on coatings properties for their use in the solution of certain tasks. Thin films of tin dioxide were obtained by the method of spray pyrolysis on glass substrates. Surface resistance and resistivity, concentration and mobility of charge carriers, the conductivity were measured, and the dependences showing the effect of preparation conditions on electrical properties of optically transparent coatings.

  18. Film Program Notes from the Current Holdings of the Anthology Film Archives; Outlines of 41 Films.

    ERIC Educational Resources Information Center

    Anthology Film Archives, New York, NY.

    This collection of film program notes includes mixed commentary on some of the films held in the Anthology Film Archives (a film and book library in New York City). Some of the films are described by synopsis of the episodes and others by translation into English of the foreign language subtitles. However, each film noted is identified by full…

  19. Obtaining of biodegradable polylactide films and fibers filled hydroxyapatite for medical purposes

    SciTech Connect

    Lytkina, D. N. Shapovalova, Y. G. Rasskazova, L. A. Kurzina, I. A. Filimoshkin, A. G.

    2015-11-17

    Relevance of the work is due to the need for new materials that are used in medicine (orthopedics, surgery, dentistry, and others) as a substitute for natural bone tissue injuries, fractures, etc. The aim of presented work is developing of a method of producing biocompatible materials based on polyesters of hydroxycarboxylic acids and calcium phosphate ceramic (hydroxyapatite, HA) with homogeneous distribution of the inorganic component. Bioactive composites based on poly-L-lactide (PL) and hydroxyapatite with homogeneous distribution were prepared. The results of scanning electron microscopy confirm homogeneous distribution of the inorganic filler in the polymer matrix. The positive effect of ultrasound on the homogeneity of the composites was determined. The rate of hydrolysis of composites was evaluated. The rate of hydrolysis of polylactide as an individual substance is 7 times lower than the rate of hydrolysis of the polylactide as a part of the composite. It was found that materials submarines HA composite and do not cause a negative response in the cells of the immune system, while contributing to anti-inflammatory cytokines released by cells.

  20. The optical properties of regenerated silk fibroin films obtained from different sources

    NASA Astrophysics Data System (ADS)

    Perotto, Giovanni; Zhang, Yuji; Naskar, Deboki; Patel, Nereus; Kaplan, David L.; Kundu, Subhas C.; Omenetto, Fiorenzo G.

    2017-09-01

    Silk fibroin possesses unique properties for bio-functional optical interfaces and has been attracting increasing interest as an optical material. Here, we report on the refractive index and absorption coefficient of silk fibroin extracted from Bombyx mori, Antheraea mylitta, Samia ricini, and Antheraea assamensis. The influence of protein molecular weight, residual water content, and crystallinity on refractive index was investigated. The parameters for the Cauchy dispersion law and Urbach absorption were determined for each of the silk fibroins. By exploiting the differences in refractive index between the different fibroins, an all-protein slab waveguide was fabricated.

  1. Physical characterization of Ge films on polyethylene obtained by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Giuffrida, L.; Torrisi, L.; Rosinski, M.; Caridi, F.; Cutroneo, M.

    2012-05-01

    A Nd:YAg laser, operating in fundamental wavelength at 1064 nm, is focused at an intensity of the order of 1010 W/cm2 to ablate a solid Ge target. A Laser Ion Source (LIS) system is employed to produce ion emission at high directionality, high current, high rate of production and high charge states. LIS is used to implant and/or to deposit Ge ions in polyethylene (UHMWPE). Mechanical (roughness, wetting ability and microhardness), optical (reflectivity and transmission) and electrical properties (resistivity) were investigated, in comparison to the pristine values, in order to reach understanding of the ion implantation/deposition effects as a function of the irradiation ion dose.

  2. Obtaining of biodegradable polylactide films and fibers filled hydroxyapatite for medical purposes

    NASA Astrophysics Data System (ADS)

    Lytkina, D. N.; Shapovalova, Y. G.; Rasskazova, L. A.; Kurzina, I. A.; Filimoshkin, A. G.

    2015-11-01

    Relevance of the work is due to the need for new materials that are used in medicine (orthopedics, surgery, dentistry, and others) as a substitute for natural bone tissue injuries, fractures, etc. The aim of presented work is developing of a method of producing biocompatible materials based on polyesters of hydroxycarboxylic acids and calcium phosphate ceramic (hydroxyapatite, HA) with homogeneous distribution of the inorganic component. Bioactive composites based on poly-L-lactide (PL) and hydroxyapatite with homogeneous distribution were prepared. The results of scanning electron microscopy confirm homogeneous distribution of the inorganic filler in the polymer matrix. The positive effect of ultrasound on the homogeneity of the composites was determined. The rate of hydrolysis of composites was evaluated. The rate of hydrolysis of polylactide as an individual substance is 7 times lower than the rate of hydrolysis of the polylactide as a part of the composite. It was found that materials submarines HA composite and do not cause a negative response in the cells of the immune system, while contributing to anti-inflammatory cytokines released by cells.

  3. Properties of poly(lactide)-whey protein isolate laminated films.

    PubMed

    Phupoksakul, Thunyaluck; Leuangsukrerk, Manusawee; Numpiboonmarn, Pidsawat; Somwangthanaroj, Anongnat; Janjarasskul, Theeranun

    2015-03-15

    This study aims to examine the feasibility of a novel multi-layer barrier film made entirely from biopolymers, which can be disposed after use in an economically and ecologically acceptable way, by employing mechanical strength and moisture barrier of poly(lactide) (PLA) films and oxygen barrier enhancement of whey protein isolate (WPI) films. The effect of glycerol was also determined. The three-layer films, PLA/WPI/PLA, were compared with those made of linear low-density polyethylene films (LLDPE/WPI/LLDPE). Composite structures of three-layer films obtained by a simple casting method using denatured WPI solution plasticised with glycerol (GLY) at three different ratios of GLY:WPI (1:4, 1:2.5 and 1:1.5). The WPI solution was applied between two base layers of corona-treated PLA or LLDPE films. The multi-layer films showed good appearance with no noticeably visible change and good adhesion of layers. PLA enhanced tensile strength of the composite structure. Oxygen permeability of the multi-layer films was significantly lower than the base films. The water vapour permeability of the structure relied mainly on the base films. The plasticiser content did not significantly affect the properties of the multi-layer structures. Results suggested that WPI could work successfully as an alternative oxygen barrier layer of multi-layer structures. © 2014 Society of Chemical Industry.

  4. Phonon transport across nano-scale curved thin films

    NASA Astrophysics Data System (ADS)

    Mansoor, Saad B.; Yilbas, Bekir S.

    2016-12-01

    Phonon transport across the curve thin silicon film due to temperature disturbance at film edges is examined. The equation for radiative transport is considered via incorporating Boltzmann transport equation for the energy transfer. The effect of the thin film curvature on phonon transport characteristics is assessed. In the analysis, the film arc length along the film centerline is considered to be constant and the film arc angle is varied to obtain various film curvatures. Equivalent equilibrium temperature is introduced to assess the phonon intensity distribution inside the curved thin film. It is found that equivalent equilibrium temperature decay along the arc length is sharper than that of in the radial direction, which is more pronounced in the region close to the film inner radius. Reducing film arc angle increases the film curvature; in which case, phonon intensity decay becomes sharp in the close region of the high temperature edge. Equivalent equilibrium temperature demonstrates non-symmetric distribution along the radial direction, which is more pronounced in the near region of the high temperature edge.

  5. 2D Magnetic Texture Analysis of Co-Cu Films

    NASA Astrophysics Data System (ADS)

    Bayirli, Mehmet; Karaagac, Oznur; Kockar, Hakan; Alper, Mursel

    2017-05-01

    The magnetic textures for the produced magnetic materials are important concepts in accordance with technical applications. Therefore, the aim of this article is to determine 2D magnetic textures of electrodeposited Co-Cu films by the measurement of hysteresis loops at the incremented angles. For that, Co-Cu films were deposited with different Co2+ in the electrolyte. In addition, the easy-axis orientation in the films from the squareness values of the angles, Mp(β) obtained by the hysteresis loops have been numerically studied using the Fourier series analysis. The differences observed in the magnetic easy-axis distributions were attributed to changes of the incorporation of Co in the films with the change of Co2+ in the electrolyte. The coefficients of Fourier series (A0 and A2n ) were also computed for 2D films. It is seen that a systematic and small decrease in A0 and an obvious decrease in A2n (n=1) were observed with increasing incorporated Co in the films. Results imply that interactions cause slightly demagnetization effect accordance with higher incorporation of Co in the films. Furthermore, the crystal structure of the Co-Cu films analysed by X-ray diffraction revealed that the films have dominantly face-centred cubic structure. Film contents analysed by energy-dispersive X-ray spectroscopy and film morphologies observed by scanning electron microscope also support the magnetic texture analysis results found by numerical computation.

  6. Towards an optimised sputtered MoS2 lubricant film

    NASA Technical Reports Server (NTRS)

    Roberts, E. W.

    1986-01-01

    It is shown that the tribological quality of MoS2 lubricant films formed by magnetron sputtering is determined by the choice of sputtering conditions. By selecting the appropriate conditions, films of extremely high lubricity and endurance (in vacuum), which are well suited to many space applications, are obtained. Such MoS2 films, when applied to precision ball hearings, give rise to the lowest torques (for the given test conditions) yet seen in our laboratory. While a remarkably good performance is obtained in vacuum, tests in air show a marked deterioration in lubricating qualities. It is demonstrated that this is attributable to the adsorption of water vapor on MoS2 surfaces and that the degree of deterioration is related to the partial pressure of water vapor present. Analysis of results indicates that the factors relevant to obtaining optimum films are deposition rate and film composition.

  7. Pyrolyzed thin film carbon

    NASA Technical Reports Server (NTRS)

    Tai, Yu-Chong (Inventor); Liger, Matthieu (Inventor); Harder, Theodore (Inventor); Konishi, Satoshi (Inventor); Miserendino, Scott (Inventor)

    2010-01-01

    A method of making carbon thin films comprises depositing a catalyst on a substrate, depositing a hydrocarbon in contact with the catalyst and pyrolyzing the hydrocarbon. A method of controlling a carbon thin film density comprises etching a cavity into a substrate, depositing a hydrocarbon into the cavity, and pyrolyzing the hydrocarbon while in the cavity to form a carbon thin film. Controlling a carbon thin film density is achieved by changing the volume of the cavity. Methods of making carbon containing patterned structures are also provided. Carbon thin films and carbon containing patterned structures can be used in NEMS, MEMS, liquid chromatography, and sensor devices.

  8. Electrically Conductive Polyimide Films

    NASA Technical Reports Server (NTRS)

    St. Clair, Anne K.; Ezzel, Stephen A.; Taylor, Larry T.; Boston, Harold G.

    1993-01-01

    Semiconducting surfaces of SnO2 formed by curing polyamic acids containing tin complexes. Polyimide films made semiconductive via incorporation of semiconductive surface layers of SnO2. If SnO2-surfaced polyimide film used as free-standing film, then semiconductive layer protected by top coat of polyimide, deposited as film from solution directly onto SnO2. Resultant films flexible and resistant to both weather and high temperature. Used on aircraft to provide resistance to lightning strikes, and in microelectronics and flexible circuitry.

  9. Thermoplastic starch films reinforced with talc nanoparticles.

    PubMed

    Castillo, Luciana; López, Olivia; López, Cintia; Zaritzky, Noemí; García, M Alejandra; Barbosa, Silvia; Villar, Marcelo

    2013-06-20

    Nanocomposite films of thermoplastic corn starch (TPS) with talc particles were obtained by thermo-compression in order to study the effect of filler on structure, optical, and thermal properties. Talc increased the films rigid phase, thus their cross-sections resulted more irregular. Talc preferential orientation within matrix and good compatibility between particles and TPS was observed by SEM. Slight crystalline structure changes in TPS matrix were measured by XRD and DSC, due to talc nucleating effect. Randomly dispersed talc nanoagglomerates and individual platelets were assessed by TEM. Laminar morphology and nano-sized particles allowed that nanocomposite films were optically transparent. TPS-talc films resulted heterogeneous materials, presenting domains rich in glycerol and others rich in starch. Talc incorporation higher than 3%, w/w increased softening resistance of the nanocomposites as stated by DMA. Relaxation temperatures of glycerol-rich phase shifted to higher values since talc reduces the mobility of starch chains.

  10. Iron films deposited on porous alumina substrates

    NASA Astrophysics Data System (ADS)

    Yamada, Yasuhiro; Tanabe, Kenichi; Nishida, Naoki; Kobayashi, Yoshio

    2016-12-01

    Iron films were deposited on porous alumina substrates using an arc plasma gun. The pore sizes (120 - 250 nm) of the substrates were controlled by changing the temperature during the anodic oxidation of aluminum plates. Iron atoms penetrated into pores with diameters of less than 160 nm, and were stabilized by forming γ-Fe, whereas α-Fe was produced as a flat plane covering the pores. For porous alumina substrates with pore sizes larger than 200 nm, the deposited iron films contained many defects and the resulting α-Fe had smaller hyperfine magnetic fields. In addition, only a very small amount of γ-Fe was obtained. It was demonstrated that the composition and structure of an iron film can be affected by the surface morphology of the porous alumina substrate on which the film is grown.

  11. Dynamical electrophotoconductivity in polycrystalline thin films

    NASA Technical Reports Server (NTRS)

    Kowel, S. T.; Kornreich, P. G.

    1982-01-01

    Polycrystalline cadmium sulfide (CdS) films were deposited on lithium niobate (LiNbO3) substrates by vacuum evaporation and annealed to obtain high photosensitivity. The change in photoconductivity of these films due to the penetration of electric fields associated with elastic waves propagating on their substrates was demonstrated and studied. The relationship between the acoustic electric field and the induced change in film conductivity was found to be a nonlinear one. The fractional change in conductivity is strongly dependent on the light intensity and the film temperature, showing a prominent maximum as a function of these quantities. The largest recorded fractional change in conductivity was about 25% at electric fields of the order of 1,000 volts per centimeter. A phenomological model was developed based on the interaction between the space charge created by the electric field and the electron trapping states in the photoconductor.

  12. Chronicles of foam films.

    PubMed

    Gochev, G; Platikanov, D; Miller, R

    2016-07-01

    The history of the scientific research on foam films, traditionally known as soap films, dates back to as early as the late 17th century when Boyle and Hooke paid special attention to the colours of soap bubbles. Their inspiration was transferred to Newton, who began systematic study of the science of foam films. Over the next centuries, a number of scientists dealt with the open questions of the drainage, stability and thickness of foam films. The significant contributions of Plateau and Gibbs in the middle/late 19th century are particularly recognized. After the "colours" method of Newton, Reinold and Rücker as well as Johhonnot developed optical methods for measuring the thickness of the thinner "non-colour" films (first order black) that are still in use today. At the beginning of the 20th century, various aspects of the foam film science were elucidated by the works of Dewar and Perrin and later by Mysels. Undoubtedly, the introduction of the disjoining pressure by Derjaguin and the manifestation of the DLVO theory in describing the film stability are considered as milestones in the theoretical development of foam films. The study of foam films gained momentum with the introduction of the microscopic foam film methodology by Scheludko and Exerowa, which is widely used today. This historical perspective serves as a guide through the chronological development of knowledge on foam films achieved over several centuries.

  13. Ceramic Composite Thin Films

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  14. Depositing Diamondlike Carbon Films

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.; Sovey, J. S.; Banks, B. A.

    1986-01-01

    New process demonstrated to make thin films (usually thousands of angstroms to few microns thick) that have properties of diamonds. Various plasma and ion-beam techniques employed to generate films. Films made by radio-frequency plasma decomposition of hydrocarbon gas or other alkanes, by low-energy carbon-ion-beam deposition, or by ion plating and dual ion technique using carbon target. Advantages of new process over others are films produced, though amorphous, are clear, extremely hard, chemically inert, of high resistivity, and have index of refraction of 3.2 properties similar to those of single-crystal diamonds. Films have possible uses in microelectronic applications, high-energy-laser and plastic windows, corrosion protection for metals, and other applications where desired properties of film shaped during the film-formation process.

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

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

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

  16. Innovative plasticized alginate obtained by thermo-mechanical mixing: Effect of different biobased polyols systems.

    PubMed

    Gao, Chengcheng; Pollet, Eric; Avérous, Luc

    2017-02-10

    Plasticized alginate films with different biobased polyols (glycerol and sorbitol) and their mixtures were successfully prepared by thermo-mechanical mixing instead of the usual casting-evaporation procedure. The microstructure and properties of the different plasticized alginate formulations were investigated by SEM, FTIR, XRD, DMTA and uniaxial tensile tests. SEM and XRD results showed that native alginate particles were largely destructured with the plasticizers (polyols and water), under a thermo-mechanical input. With increasing amount of plasticizers, the samples showed enhanced homogeneity while their thermal and mechanical properties decreased. Compared to sorbitol, glycerol resulted in alginate films with a higher flexibility due to its better plasticization efficiency resulting from its smaller size and higher hydrophilic character. Glycerol and sorbitol mixtures seemed to be an optimum to obtain the best properties. This work showed that thermo-mechanical mixing is a promising method to produce, at large scale, plasticized alginate-based films with improved properties.

  17. YBCO thin film evaporation on as-deposited silver film on MgO

    NASA Astrophysics Data System (ADS)

    Azoulay, J.

    1999-11-01

    YBa 2Cu 3O 7- δ (YBCO) thin film was evaporated on as-deposited Ag buffer layer on MgO substrate. A simple, inexpensive vacuum system equipped with one resistively heated source was used. The subsequent heat treatment was carried out under low oxygen partial pressure at a relatively low temperature and short dwelling time. The films thus obtained were characterized for electrical properties using DC four-probe electrical measurements and inspected for structural properties and chemical composition by scanning electron microscopy (SEM). It is shown that YBCO thin film can grow on as-deposited thin silver layer on MgO substrate.

  18. Magneto-optical activity in organic thin film materials

    NASA Astrophysics Data System (ADS)

    Vleugels, Rick; de Vega, Laura; Brullot, Ward; Verbiest, Thierry; Gómez-Lor, Berta; Gutierrez-Puebla, Enrique; Hennrich, Gunther

    2016-12-01

    A series of CF3-capped phenylacetylenes with varying symmetry is obtained by a conventional palladium-catalyzed cross-coupling protocol. The phenylacetylene targets form thin films both, liquid crystalline (LC) and crystalline in nature depending on their molecular structure. The magneto-optical activity of the resulting organic material is extraordinarily high as proved by Faraday rotation spectroscopy on thin film devices.

  19. Molecular organization in perylene tetracarboxylic di-imide solid films

    NASA Astrophysics Data System (ADS)

    Akers, K.; Aroca, R.; Hort, A. M.; Loutfy, R. O.

    The vibrational spectra of thin solid films of three perylene tetracarboxylic di-imide derivatives (phenyl, methyl, and unsubstituted) are reported. A preferred molecular orientation in the evaporated solid films emerged for all three perylene derivatives from the i.r. data. Raman spectra obtained in resonance with the absorption band were characteristic of scattering via a Herzberg—Teller mechanism.

  20. Thin Films of the Rare-Earth Metals,

    DTIC Science & Technology

    A vacuum thermal method of producing thin films (1-10 mu m) of rare earth metals (Sm, Dy, Tn, and Yb) is described and its efficiency is compared with...existing methods (which are briefly reviewed). A very effective method of obtaining the thin films in question is by reducing the corresponding