Sample records for cual reactive multilayers
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Moon, Hock Key; Yoon, Jaehong; Kim, Hyungjun; Lee, Nae-Eung
2013-05-01
One of the most important issues in future Cu-based interconnects is to suppress the resistivity increase in the Cu interconnect line while decreasing the line width below 30 nm. For the purpose of mitigating the resistivity increase in the nanoscale Cu line, alloying Cu with traces of other elements is investigated. The formation of a Cu alloy layer using chemical vapor deposition or electroplating has been rarely studied because of the difficulty in forming Cu alloys with elements such as Al. In this work, Cu-Al alloy films were successfully formed after thermal annealing of Cu/Al multilayers deposited by cyclic metal-organic chemical vapor deposition (C-MOCVD). After the C-MOCVD of Cu/Al multilayers without gas phase reaction between the Cu and Al precursors in the reactor, thermal annealing was used to form Cu-Al alloy films with a small Al content fraction. The resistivity of the alloy films was dependent on the Al precursor delivery time and was lower than that of the aluminum-free Cu film. No presence of intermetallic compounds were detected in the alloy films by X-ray diffraction measurements and transmission electron spectroscopy.
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Self-Propagating Reactive Fronts in Compacts of Multilayered Particles
International Nuclear Information System (INIS)
Sraj, I.; Vohra, M.; Alawieh, L.; Weihs, T.P.; Knio, O.M.
2013-01-01
Reactive multilayered foils in the form of thin films have gained interest in various applications such as joining, welding, and ignition. Typically, thin film multilayers support self-propagating reaction fronts with speeds ranging from 1 to 20 m/s. In some applications, however, reaction fronts with much smaller velocities are required. This recently motivated Fritz et al. (2011) to fabricate compacts of regular sized/shaped multilayered particles and demonstrate self-sustained reaction fronts having much smaller velocities than thin films with similar layering. In this work, we develop a simplified numerical model to simulate the self-propagation of reactive fronts in an idealized compact, comprising identical Ni/Al multilayered particles in thermal contact. The evolution of the reaction in the compact is simulated using a two-dimensional transient model, based on a reduced description of mixing, heat release, and thermal transport. Computed results reveal that an advancing reaction front can be substantially delayed as it crosses from one particle to a neighboring particle, which results in a reduced mean propagation velocity. A quantitative analysis is thus conducted on the dependence of these phenomena on the contact area between the particles, the thermal contact resistance, and the arrangement of the multilayered particles.
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Self-Propagating Reactive Fronts in Compacts of Multilayered Particles
Directory of Open Access Journals (Sweden)
Ihab Sraj
2013-01-01
Full Text Available Reactive multilayered foils in the form of thin films have gained interest in various applications such as joining, welding, and ignition. Typically, thin film multilayers support self-propagating reaction fronts with speeds ranging from 1 to 20 m/s. In some applications, however, reaction fronts with much smaller velocities are required. This recently motivated Fritz et al. (2011 to fabricate compacts of regular sized/shaped multilayered particles and demonstrate self-sustained reaction fronts having much smaller velocities than thin films with similar layering. In this work, we develop a simplified numerical model to simulate the self-propagation of reactive fronts in an idealized compact, comprising identical Ni/Al multilayered particles in thermal contact. The evolution of the reaction in the compact is simulated using a two-dimensional transient model, based on a reduced description of mixing, heat release, and thermal transport. Computed results reveal that an advancing reaction front can be substantially delayed as it crosses from one particle to a neighboring particle, which results in a reduced mean propagation velocity. A quantitative analysis is thus conducted on the dependence of these phenomena on the contact area between the particles, the thermal contact resistance, and the arrangement of the multilayered particles.
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A metastable HCP intermetallic phase in Cu-Al bilayer films
Energy Technology Data Exchange (ETDEWEB)
Cha, Limei
2006-07-01
For the present study, three kinds of layered Cu/Al films have been fabricated. The first kind of samples were multilayered Cu/Al films deposited by sputtering on (001)Si. The individual layer thicknesses were 100 nm, 200 nm and 400 nm, while the total film thickness of 800 nm was kept constant, thus leading to multilayer systems with 8, 4 and 2 layers, respectively. The second type of samples were Cu/Al bilayer films grown on (0001) sapphire by sputtering, with individual layer thicknesses of 400 nm. The third type of samples were bilayer films (100 nm Cu and 100 nm Al) deposited on (0001)sapphire by MBE at room temperature. Applying conventional transmission electron microscopy and X-ray diffraction, different epitaxial growth behaviors were found in these films. All multilayer films from the first type were polycrystalline. The second type of films show a (111) FCC texture and possess intermetallic phases at the interfaces. HRTEM investigations displayed that along [111]FCC, the atomic structure of the interlayer has an ABAB stacking sequence, which is identical with a hexagonal close-packed (HCP) structure in [0001] direction, but not with the ABCABC stacking sequence of Cu and Al in [111]FCC. The lattice parameters of the HCP structure at the interlayer were determined from a model which gave the best agreement between the experimental and simulated images. The parameters are: a=b=0.256 nm, c=0.419 nm, ?=120 , with the space group of P6m2. Furthermore, lattice distortion analysis revealed that the lattice parameters of the HCP phase are increasing from the near-Cu-side to the near-Al-side. The chemical composition of the interlayer was investigated by energy dispersive X-ray spectroscopy (EDS). EDS linescans were performed from pure Al to pure Cu layers. In order to examine the stability of this HCP phase, in-situ heating experiments were performed in the HRTEM at {proportional_to}600 C. Ex-situ heating experiments were performed at different temperatures to
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Reactive diffusion and superconductivity of Nb3Al multilayer films
International Nuclear Information System (INIS)
Vandenberg, J.M.; Hong, M.; Hamm, R.A.; Gurvitch, M.
1985-01-01
Thin films of A15 Nb 3 Al have been prepared by reactive diffusion of sputter-deposited Nb/Al multilayers. The diffusion reactions were studied by in situ annealing x-ray diffraction in the temperature range 50--950 0 C. Initially the Nb and Al sublayers react to form the phase NbAl 3 . This interface reaction prevents the formation of the sigma-phase Nb 2 Al, frequently found as a second phase in A15 Nb 3 Al materials; NbAl 3 reacts with the remaining Nb to form the A15 phase. The highest T/sub c/, 16.2 K measured resistively and 15.2 K inductively, was found in a Nb/Al multilayer with an A15 cell parameter a 0 = 5.195 A which corresponds to approx.20 at. % Al. From a comparison with previous investigations of the T/sub c/ dependence on Al concentration and A15 cell parameter, it is concluded that a small amount of the A15 phase has a higher composition of 22--23 at. % Al
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Nanostructuring of Mo/Si multilayers by means of reactive ion etching using a three-level mask
International Nuclear Information System (INIS)
Dreeskornfeld, L.; Haindl, G.; Kleineberg, U.; Heinzmann, U.; Shi, F.; Volland, B.; Rangelow, I.W.; Majkova, E.; Luby, S.; Kostic,; Matay, L.; Hrkut, P.; Hudek, P.; Lee, H.-Y.
2004-01-01
Recently, Mo/Si multilayer reflectors have been gaining industry interest as a promising choice for the next generation extreme ultraviolet mask material for printing sub 70 nm feature size devices. A reactive ion etching system with optimized hardware using CHF 3 /Ar process regime shows the capability for highly anisotropic etching of sub congruent with 400 nm feature sizes in Mo/Si test multilayers with ten periods and a bilayer thickness of 7.8 nm which were prepared by e-beam evaporation. A three-level-mask technique consisting of a top resist mask layer poly-methyl-meth-acrylate, a middle hard amorphous Si mask layer and a bottom-level polyimide layer is used to create the etch mask. The etch characteristics of the polyimide film is shown to be one of the major factors determining the success of the described multilayer etching process. The developed etching technology demonstrates superior process performance without facets, excellent uniformity and good profile control. No contamination, degeneration or defect generation in the unetched multilayer structure could be detected. This non-conventional process results in minimum deposition during the etching thus eliminating the need for a dry or wet cleaning. Sidewall angles in Mo/Si multilayers of 85 deg. , without undercut, bowing and ripples resulting in smooth sidewalls are achieved
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Structure and mechanical properties of reactive sputter deposited TiN/TaN multilayered films
International Nuclear Information System (INIS)
Soe, W.H.; Yamamoto, R.; Ueda, H.; Shima, N.
1998-01-01
TiN/TaN multilayers were grown by reactive magnetron sputtering on WC-Co sintered hard alloy and MgO(100) single crystal substrates. Multilayer structure and composition modulation amplitudes were studied using x-ray diffraction method. Hardness and elastic modulus were measured by nanoindentation tester. For bilayer thickness (Λ) larger than 80 angstrom, hardness are lower than rule-of-mixtures value of individual single layers, and increased rapidly with decreasing Λ, peaking at hardness values ∼33% higher than that at Λ = 43 angstrom. As a result of analysis the inclination of applied load for indenter displacement on P-h curve (ΔP/Δh), this paper exhibits that the enhancement of the resistance to dislocation motion and elastic anomaly due to coherency strains are responsible for the hardness change
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Lamnawar, Khalid; Maazouz, Abderrahim
2008-07-01
Coextrusion technologies are commonly used to produce multilayered composite sheets or films for a large range of applications from food packaging to optics. The contrast of rheological properties between layers can lead to interfacial instabilities during flow. Important theoretical and experimental advances regarding the stability of compatible and incompatible polymers have, during the last decades, been made using a mechanical approach. However, few research efforts have been dedicated to the physicochemical affinity between the neighboring layers. The present study deals with the influence of this affinity on interfacial instabilities for functionalized incompatible polymers. Polyamide (PA6)/polyethylene grafted with glycidyl methacrylate (PE-GMA) was used as a reactive system and PE/PA6 as a non reactive one. Two grades of polyamide (PA6) were used in order to change the viscosity and elasticity ratios between PE (or PE-GMA) and PA6. It was experimentally confirmed, in this case, that weak disturbance can be predicted by considering an interphase of non-zero thickness (corresponding to an interdiffusion/reaction zone) instead of a purely geometrical interface between the two reactive layers. According to the rheological investigations from previous work which the interphase effect can be probed, an experimental strategy was here formulated to optimize the process by listing the parameters that controlled the stability of the reactive multilayer flows. Hence, based on this analysis, guidelines for a stable coextrusion of reactive functionalized polymers can be provided coupling the classical parameters (viscosity, elasticity and layer ratios) and the physicochemical affinity at the polymer/polymer interface.
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The dynamics of Al/Pt reactive multilayer ignition via pulsed-laser irradiation
Energy Technology Data Exchange (ETDEWEB)
Murphy, Ryan D.; Reeves, Robert V.; Yarrington, Cole D.; Adams, David P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States)
2015-12-07
Reactive multilayers consisting of alternating layers of Al and Pt were irradiated by single laser pulses ranging from 100 μs to 100 ms in duration, resulting in the initiation of rapid, self-propagating reactions. The threshold intensities for ignition vary with the focused laser beam diameter, bilayer thickness, and pulse length and are affected by solid state reactions and conduction of heat away from the irradiated regions. High-speed photography was used to observe ignition dynamics during irradiation and elucidate the effects of heat transfer into a multilayer foil. For an increasing laser pulse length, the ignition process transitioned from a more uniform to a less uniform temperature profile within the laser-heated zone. A more uniform temperature profile is attributed to rapid heating rates and heat localization for shorter laser pulses, and a less uniform temperature profile is due to slower heating of reactants and conduction during irradiation by longer laser pulses. Finite element simulations of laser heating using measured threshold intensities indicate that micron-scale ignition of Al/Pt occurs at low temperatures, below the melting point of both reactants.
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Kish, Orel; Froumin, Natalya; Aizenshtein, Michael; Frage, Nachum
2014-05-01
Wettability and interfacial interaction of the Ta2O5/Cu-Al system were studied. Pure Cu does not wet the Ta2O5 substrate, and improved spreading is achieved when relatively a high fraction of the active element (~40 at.% Al) was added. The Al2O3 and AlTaO4 phases were observed at the Ta2O5/Cu-Al interface. A thermodynamic evaluation allowed us to suggest that the lack of wetting bellow 40 at.% Al is due to the presence of a native oxide, which covers the drop. The conditions of the native oxide decomposition and the formation of the volatile Al2O suboxide strongly depend on the vacuum level during sessile drop experiments and the composition of the Cu-Al alloy. In our case, Al contents greater than 40% provides thermodynamic conditions for the formation of Al2O (as a result of Al reaction with Al2O3) and the drop spreading. It was suggested that the final contact angle in the Ta2O5/Cu-Al system (50°) is determined by Ta adsorption on the newly formed alumina interlayer.
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Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides
International Nuclear Information System (INIS)
Qu, Jun; He, Xiaoman; Chen, Min; Hu, Huimin; Zhang, Qiwu; Liu, Xinzhong
2017-01-01
In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu_2(OH)_2CO_3) and aluminum hydroxide (Al(OH)_3) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.
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Mechanochemical synthesis of Cu-Al and methyl orange intercalated Cu-Al layered double hydroxides
Energy Technology Data Exchange (ETDEWEB)
Qu, Jun, E-mail: forsjun@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); He, Xiaoman; Chen, Min; Hu, Huimin [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Zhang, Qiwu, E-mail: zhangqw@whut.edu.cn [School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei 430070 (China); Liu, Xinzhong [College of Ecological Environment and Urban Construction, Fujian University of Technology, Fuzhou 350118 China (China)
2017-04-15
In this study, a mechanochemical route to synthesize a Cu-Al layered double hydroxide (LDH) and a methyl orange (MO) intercalated one (MO-LDH) was introduced, in which basic cupric carbonate (Cu{sub 2}(OH){sub 2}CO{sub 3}) and aluminum hydroxide (Al(OH){sub 3}) with Cu/Al molar ratio at 2/1 was first dry ground for 2 h and then agitated in water or methyl orange solution for another 4 h to obtain the LDH and MO-LDH products without any heating operation. The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermogravimetry (TG), Differential scanning calorimetry (DSC) and Scanning electron microscopy (SEM). The products showed high crystallinity phase of Cu-Al and MO intercalated Cu-Al LDH with no evident impurities, proving that the craft introduced here was facile and effective. The new idea can be applied in other fields to produce organic-inorganic composites. - Highlights: • A facile mechanochemical route to synthesize Cu-Al and MO intercalated Cu-Al LDH. • The products possesses high crystalline of LDH phase with no impure phases. • The dry milling process induces the element substitution between the raw materials. • The agitation operation helps the grain growth of LDH.
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Energy Technology Data Exchange (ETDEWEB)
Alemón, B.; Flores, M. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jal. 45101 (Mexico); Canto, C. [Instituto de Física, UNAM, Avenida de la Investigación S/N, Coyoacán, Mexico, DF 04510 (Mexico); Andrade, E., E-mail: andrade@fisica.unam.mx [Instituto de Física, UNAM, Avenida de la Investigación S/N, Coyoacán, Mexico, DF 04510 (Mexico); Lucio, O.G. de [Instituto de Física, UNAM, Avenida de la Investigación S/N, Coyoacán, Mexico, DF 04510 (Mexico); Rocha, M.F. [ESIME-Z, Instituto Politécnico Nacional, ALM Zacatenco, Mexico, DF 07738 (Mexico); Broitman, E. [Thin Films Physics Division, IFM, Linköping University, SE-58183 Linköping (Sweden)
2014-07-15
A novel TiAlCN/CN{sub x} multilayer coating, consisting of nine TiAlCN/CN{sub x} periods with a top layer 0.5 μm of CN{sub x}, was designed to enhance the corrosion resistance of CoCrMo biomedical alloy. The multilayers were deposited by dc and RF reactive magnetron sputtering from Ti{sub 0.5}Al{sub 0.5} and C targets respectively in a N{sub 2}/Ar plasma. The corrosion resistance and mechanical properties of the multilayer coatings were analyzed and compared to CoCrMo bulk alloy. Ion beam analysis (IBA) and X-ray diffraction tests were used to measure the element composition profiles and crystalline structure of the films. Corrosion resistance was evaluated by means of potentiodynamic polarization measurements using simulated body fluid (SBF) at typical body temperature and the nanomechanical properties of the multilayer evaluated by nanoindentation tests were analyzed and compared to CoCrMo bulk alloy. It was found that the multilayer hardness and the elastic recovery are higher than the substrate of CoCrMo. Furthermore the coated substrate shows a better general corrosion resistance than that of the CoCrMo alloy alone with no observation of pitting corrosion.
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International Nuclear Information System (INIS)
Jacques, S.; Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P.
2013-01-01
In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called “interphase” between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC–TiC) n interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC–TiC) n films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.
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Jacques, S.; Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P.
2013-06-01
In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called "interphase" between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC-TiC)n interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC-TiC)n films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.
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Stress in tungsten carbide-diamond like carbon multilayer coatings
Pujada, B.R.; Tichelaar, F.D.; Janssen, G.C.A.M.
2007-01-01
Tungsten carbide-diamond like carbon (WC-DLC) multilayer coatings have been prepared by sputter deposition from a tungsten-carbide target and periodic switching on and off of the reactive acetylene gas flow. The stress in the resulting WC-DLC multilayers has been studied by substrate curvature.
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Reactive resistance welding of Ti6Al4V alloy with the use of Ni(V)/Al multilayers
Energy Technology Data Exchange (ETDEWEB)
Maj, Lukasz; Morgiel, Jerzy [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, Krakow (Poland); Mars, Krzysztof; Godlewska, Elzbieta [Faculty of Materials Science and Ceramics, AGH University of Science and Technology, Krakow (Poland)
2017-02-15
The freestanding Ni(V)/Al multilayer foil was applied as a filler material in order to join Ti6Al4V alloy with the use of reactive resistance welding (RRW) technique. Present investigations, performed with the use of transmission electron microscopy (TEM) method, allowed to show that an application of high current (I = 400 A for 2 min in vacuum conditions ∝10{sup -1} mbar) transformed the Ni(V)/Al multilayers into fine grain (<300 nm) NiAl phase. It also showed that the RRW process led to the formation of firm connection with nanoporosity limited only to the original contact plane between base material and the foil. Simultaneously, the formation of a narrow strip of crystallites of Ti{sub 3}Al intermetallic phase elongated along the joint line (average size of ∝200 nm) was observed. The base material was separated from the joint area by a layer of up to ∝2 μm thickness of nearly defect free α-Ti and β-Ti grains from a heat affected zone (HAZ). The performed experiment proved that Ni(V)/Al multilayer could serve as a filler material for joining of Ti6Al4V alloys even without additional solder layer. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
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Liang, Wei; Yang, Jijun; Zhang, Feifei; Lu, Chenyang; Wang, Lumin; Liao, Jiali; Yang, Yuanyou; Liu, Ning
2018-04-01
This study investigates the improved irradiation tolerance of reactive gas pulse (RGP) sputtered TiN coatings which has hybrid architecture of multilayered and compositionally graded structures. The multilayered RGP-TiN coating is composed of hexagonal close-packed Ti phase and face-centred cubic TiN phase sublayers, where the former sublayer has a compositionally graded structure and the latter one maintains constant stoichiometric atomic ratio of Ti:N. After 100 keV He ion irradiation, the RGP-TiN coating exhibits improved irradiation resistance compared with its single layered (SL) counterpart. The size and density of He bubbles are smaller in the RGP-TiN coating than in the SL-TiN coating. The irradiation-induced surface blistering of the coatings shows a similar tendency. Meanwhile, the irradiation hardening and adhesion strength of the RGP-TiN coatings were not greatly affected by He irradiation. Moreover, the irradiation damage tolerance of the coatings can be well tuned by changing the undulation period number of N2 gas flow rate. Detailed analysis suggested that this improved irradiation tolerance could be related to the combined contribution of the multilayered and compositionally graded structures.
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Self organized formation of Ge nanocrystals in multilayers
Zschintzsch-Dias, Manuel
2012-01-01
The aim of this work is to create a process which allows the tailored growth of Ge nanocrystals for use in photovoltic applications. The multilayer systems used here provide a reliable method to control the Ge nanocrystal size after phase separation. In this thesis, the deposition of GeOx/SiO2 and Ge:SiOx~ 2/SiO2 multilayers via reactive dc magnetron sputtering and the self-ordered Ge nanocrystal formation within the GeOx and Ge:SiOx~ 2 sublayers during subsequent annealing is investigated...
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Saurer, Eric M.; Flessner, Ryan M.; Buck, Maren E.; Lynn, David M.
2011-01-01
We report on the fabrication of covalently crosslinked and amine-reactive hollow microcapsules using ‘reactive’ layer-by-layer assembly to deposit thin polymer films on sacrificial microparticle templates. Our approach is based on the alternating deposition of layers of a synthetic polyamine and a polymer containing reactive azlactone functionality. Multilayered films composed of branched poly(ethylene imine) (BPEI) and poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) were fabricated layer-by-layer on the surfaces of calcium carbonate and glass microparticle templates. After fabrication, these films contained residual azlactone functionality that was accessible for reaction with amine-containing molecules. Dissolution of the calcium carbonate or glass cores using aqueous ethylenediamine tetraacetic acid (EDTA) or hydrofluoric acid (HF), respectively, led to the formation of hollow polymer microcapsules. These microcapsules were robust enough to encapsulate and retain a model macromolecule (FITC-dextran) and were stable for at least 22 hours in high ionic strength environments, in low and high pH solutions, and in several common organic solvents. Significant differences in the behaviors of capsules fabricated on CaCO3 and glass cores were observed and characterized using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Whereas capsules fabricated on CaCO3 templates collapsed upon drying, capsules fabricated on glass templates remained rigid and spherical. Characterization using EDS suggested that this latter behavior results, at least in part, from the presence of insoluble metal fluoride salts that are trapped or precipitate within the walls of capsules after etching of the glass cores using HF. Our results demonstrate that the assembly of BPEI/PVDMA films on sacrificial templates can be used to fabricate reactive microcapsules of potential use in a wide range of fields, including catalysis, drug and gene delivery, imaging, and
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Nanolaminated TiN/Mo2N hard multilayer coatings
International Nuclear Information System (INIS)
Martev, I N; Dechev, D A; Ivanov, N P; Uzunov, T S D; Kashchieva, E P
2010-01-01
The paper presents results on the synthesis of hard multilayer coatings consisting of titanium nitride and molybdenum nitride thin films with thickness of several nm. The TiN and Mo 2 N films were successively deposited by reactive DC magnetron sputtering. These multilayer structures were investigated by Auger electron spectroscopy (AES), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray diffraction (XRD), cross-section scanning electron microscopy (CSSEM) and cross-section electron probe microanalysis (CSEPMA). The mechanical properties of the multilayer coatings, namely, hardness, Young's modulus and the coefficient of plastic deformation were measured. The adhesion was evaluated by the Rockwell-C-impact test. Coatings with different total thickness were examined with respect to adhesion to substrates of tool materials.
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Energy Technology Data Exchange (ETDEWEB)
Adams, David P. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Hirschfeld, Deidre A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Hooper, Ryan J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Manuel, Michelle V. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2015-09-01
Reactive multilayer foils have the potential to be used as local high intensity heat sources for a variety of applications. Much of the past research effort concerning these materials have focused on understanding the structure-property relationships of the foils that govern the energy released during a reaction. To enhance the ability of researchers to more rapidly develop technologies based on reactive multilayer foils, a deeper and more predictive understanding of the relationship between the heat released from the foil and microstructural evolution in the neighboring materials is needed. This work describes the development of a numerical model for the purpose of evaluating new foil-substrate combinations for screening and optimization. The model is experimentally validated using a commercially available Ni-Al multilayer foils and different alloys.
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Technique for etching monolayer and multilayer materials
Bouet, Nathalie C. D.; Conley, Raymond P.; Divan, Ralu; Macrander, Albert
2015-10-06
A process is disclosed for sectioning by etching of monolayers and multilayers using an RIE technique with fluorine-based chemistry. In one embodiment, the process uses Reactive Ion Etching (RIE) alone or in combination with Inductively Coupled Plasma (ICP) using fluorine-based chemistry alone and using sufficient power to provide high ion energy to increase the etching rate and to obtain deeper anisotropic etching. In a second embodiment, a process is provided for sectioning of WSi.sub.2/Si multilayers using RIE in combination with ICP using a combination of fluorine-based and chlorine-based chemistries and using RF power and ICP power. According to the second embodiment, a high level of vertical anisotropy is achieved by a ratio of three gases; namely, CHF.sub.3, Cl.sub.2, and O.sub.2 with RF and ICP. Additionally, in conjunction with the second embodiment, a passivation layer can be formed on the surface of the multilayer which aids in anisotropic profile generation.
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Multilayer Control for Inverters in Parallel Operation without Intercommunications
DEFF Research Database (Denmark)
Hua, Ming; Hu, Haibing; Xing, Yan
2012-01-01
In this paper, a multilayer control is proposed for inverters able to operate in parallel without intercommunications. The first control layer is an improved droop method that introduces power proportional terms into the conventional droop scheme, letting both active and reactive power to be shared...
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Bedane, T.; Di Maio, L.; Scarfato, P.; Incarnato, L.; Marra, F.
2015-12-01
The barrier performance of multilayer polymeric films for food applications has been significantly improved by incorporating oxygen scavenging materials. The scavenging activity depends on parameters such as diffusion coefficient, solubility, concentration of scavenger loaded and the number of available reactive sites. These parameters influence the barrier performance of the film in different ways. Virtualization of the process is useful to characterize, design and optimize the barrier performance based on physical configuration of the films. Also, the knowledge of values of parameters is important to predict the performances. Inverse modeling and sensitivity analysis are sole way to find reasonable values of poorly defined, unmeasured parameters and to analyze the most influencing parameters. Thus, the objective of this work was to develop a model to predict barrier properties of multilayer film incorporated with reactive layers and to analyze and characterize their performances. Polymeric film based on three layers of Polyethylene terephthalate (PET), with a core reactive layer, at different thickness configurations was considered in the model. A one dimensional diffusion equation with reaction was solved numerically to predict the concentration of oxygen diffused into the polymer taking into account the reactive ability of the core layer. The model was solved using commercial software for different film layer configurations and sensitivity analysis based on inverse modeling was carried out to understand the effect of physical parameters. The results have shown that the use of sensitivity analysis can provide physical understanding of the parameters which highly affect the gas permeation into the film. Solubility and the number of available reactive sites were the factors mainly influencing the barrier performance of three layered polymeric film. Multilayer films slightly modified the steady transport properties in comparison to net PET, giving a small reduction
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Multilayer control for inverters in parallel operation without signal interconnection
DEFF Research Database (Denmark)
Hua, Ming; Hu, Haibing; Xing, Yan
2011-01-01
A multilayer control is proposed for inverters with wireless parallel operation in this paper. The control is embedded in every inverter respectively and consists of three layers. The first layer is based on an improved droop method, which shares the active and reactive power in each module...
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Reactive diffusion in amorphous Fe-B and Co-Zr multilayer films
International Nuclear Information System (INIS)
Stobiecki, F.
1989-01-01
The diffusion in Fe 1-x B x /Fe 1-y B y and Co 1-x Zr x /Co 1-y Zr y amorphous bi- and multilayers was investigated. The dependence of the diffusion coefficient on concentration was observed. This effect is explained taking into account the concentration dependence of mixing enthalpy correlated with chemical short range order in the amorphous state
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Behavior of aluminum oxide, intermetallics and voids in Cu-Al wire bonds
International Nuclear Information System (INIS)
Xu, H.; Liu, C.; Silberschmidt, V.V.; Pramana, S.S.; White, T.J.; Chen, Z.; Acoff, V.L.
2011-01-01
Nanoscale interfacial evolution in Cu-Al wire bonds during isothermal annealing from 175 deg. C to 250 deg. C was investigated by high resolution transmission electron microscopy (HRTEM). The native aluminum oxide film (∼5 nm thick) of the Al pad migrates towards the Cu ball during annealing. The formation of intermetallic compounds (IMC) is controlled by Cu diffusion, where the kinetics obey a parabolic growth law until complete consumption of the Al pad. The activation energies to initiate crystallization of CuAl 2 and Cu 9 Al 4 are 60.66 kJ mol -1 and 75.61 kJ mol -1 , respectively. During IMC development, Cu 9 Al 4 emerges as a second layer and grows together with the initial CuAl 2 . When Al is completely consumed, CuAl 2 transforms to Cu 9 Al 4 , which is the terminal product. Unlike the excessive void growth in Au-Al bonds, only a few voids nucleate in Cu-Al bonds after long-term annealing at high temperatures (e.g., 250 o C for 25 h), and their diameters are usually in the range of tens of nanometers. This is due to the lower oxidation rate and volumetric shrinkage of Cu-Al IMC compared with Au-Al IMC.
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Herget, Philipp; O'Sullivan, Eugene J.; Romankiw, Lubomyr T.; Wang, Naigang; Webb, Bucknell C.
2016-07-05
A mechanism is provided for an integrated laminated magnetic device. A substrate and a multilayer stack structure form the device. The multilayer stack structure includes alternating magnetic layers and diode structures formed on the substrate. Each magnetic layer in the multilayer stack structure is separated from another magnetic layer in the multilayer stack structure by a diode structure.
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Vaiana, Michael; Muldoon, Sarah Feldt
2018-01-01
The field of neuroscience is facing an unprecedented expanse in the volume and diversity of available data. Traditionally, network models have provided key insights into the structure and function of the brain. With the advent of big data in neuroscience, both more sophisticated models capable of characterizing the increasing complexity of the data and novel methods of quantitative analysis are needed. Recently, multilayer networks, a mathematical extension of traditional networks, have gained increasing popularity in neuroscience due to their ability to capture the full information of multi-model, multi-scale, spatiotemporal data sets. Here, we review multilayer networks and their applications in neuroscience, showing how incorporating the multilayer framework into network neuroscience analysis has uncovered previously hidden features of brain networks. We specifically highlight the use of multilayer networks to model disease, structure-function relationships, network evolution, and link multi-scale data. Finally, we close with a discussion of promising new directions of multilayer network neuroscience research and propose a modified definition of multilayer networks designed to unite and clarify the use of the multilayer formalism in describing real-world systems.
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Nitridation and contrast of B4C/La interfaces and X-ray multilayer optics
Tsarfati, T.; van de Kruijs, Robbert Wilhelmus Elisabeth; Zoethout, E.; Bijkerk, Frederik
2010-01-01
Chemical diffusion and interlayer formation in thin layers and at interfaces is of increasing influence in nanoscopic devices such as nano-electronics, magneto-optical storage and multilayer X-ray optics. We show that with the nitridation of reactive B4C/La interfaces, both the chemical and optical
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Strength and Numerical Analysis in the Design of Permeable Reactive Barriers
Pawluk, Katarzyna; Wrzesiński, Grzegorz; Lendo-Siwicka, Marzena
2017-10-01
Permeable reactive barriers are one of the most important in situ technologies in groundwater remediation. Most of the installed PRBs have tended to use singular reactive media, but there is an increasing number of applications using combined or sequenced media to treat mixtures of contaminants within a groundwater plume. The concept of a multi-layered permeable reactive barrier (MPRB) to prevent and protect groundwater along traffic routes, especially in ecologically and naturally valuable areas, was developed following several field and laboratory investigations conducted in the Department of Geotechnical Engineering of the Warsaw University of Life Sciences. In accordance with the guidelines of the Interstate Technology & Regulatory Council for the selection of reactive materials, numerous laboratory and field investigations should be performed to determine the environmental conditions, type and concentrations of the contaminants, and the physical-chemical and permeability properties of the reactive materials. However, the deformation and strength properties of the reactive materials should be also considered in the design and evaluation of the safety conditions. In this paper, strength and deformation properties of silica spongolite, zeolite, and activated carbon were investigated using direct shear and oedometer tests. The laboratory test results were used in numerical calculations with the application of the finite element method. The aim of this study was to define the impact of the installation stages of a multi-layered permeable reactive barrier on the stability of a road embankment. Numerical analysis may prevent, reduce or eliminate the risk in the case of a breakdown during the construction or/and exploitation of a PRB.
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Energy Technology Data Exchange (ETDEWEB)
Pigozzi, Giancarlo; Janczak-Rusch, Jolanta; Passerone, Daniele; Antonio Pignedoli, Carlo; Patscheider, Joerg; Jeurgens, Lars P. H. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Antusek, Andrej [Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Faculty of Materials Science and Technology, Slovak University of Technology in Bratislava, Paulinska 16, 917 24 Trnava (Slovakia); Parlinska-Wojtan, Magdalena [Empa, Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf (Switzerland); University of Rzeszow, Institute of Physics, ul. Rejtana 16a, 35-959 Rzeszow (Poland); Bissig, Vinzenz [Kirsten Soldering AG, Hinterbergstrasse 32, CH-6330 Cham (Switzerland)
2012-10-29
Nano-sized Ag-Cu{sub 8nm}/AlN{sub 10nm} multilayers were deposited by reactive DC sputtering on {alpha}-Al{sub 2}O{sub 3}(0001) substrates. Investigation of the phase constitution and interface structure of the multilayers evidences a phase separation of the alloy sublayers into nanosized grains of Ag and Cu. The interfaces between the Ag grains and the quasi-single-crystalline AlN sublayers are semi-coherent, whereas the corresponding Cu/AlN interfaces are incoherent. The orientation relationship between Ag and AlN is constant throughout the entire multilayer stack. These observations are consistent with atomistic models of the interfaces as obtained by ab initio calculations.
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Plastic Deformation Induced by Nanoindentation Test Applied on ZrN/Si3N4 Multilayer Coatings
Directory of Open Access Journals (Sweden)
Zhengtao Wu
2017-12-01
Full Text Available ZrN/Si3N4 multilayer coating that alternates with either nanocrystalline ZrN or amorphous Si3N4 interlayers was fabricated by reactively magnetron sputtering in an Ar-N2 mixture atmosphere. The thicknesses of the nanocrystalline ZrN and the amorphous Si3N4 interlayers are ~12.5 and 2.5 nm, respectively. The ZrN/Si3N4 coating exhibits a promoted hardness of 28.6 ± 1.2 GPa when compared to the binary ZrN. Microstructure evolution just underneath the nanoindentation impression of the ZrN/Si3N4 multilayer coating has been investigated. The result indicates that both ZrN nanograin rotations and plastic flow of the Si3N4 interlayers contribute to the permanent deformation of the multilayer coating induced by the nanoindentation. In addition, the introduction of the a-Si3N4 interlayers hinders both the initiation and propagation of microcracks when the multilayer coating was applied to the scratch test. The propagation deflection of the microcracks was observed attributed to the heterogenous interface, which produces the hardness promotion of the multilayer coating eventually.
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First-principles study of atomic ordering in bcc Cu-Al
Lanzini, F.; Gargano, P. H.; Alonso, P. R.; Rubiolo, G. H.
2011-01-01
The order-disorder transitions and phase stability in the body centered cubic structure of Cu-Al binary alloys are studied by means of theoretical methods. The total energy of different ordered compounds sharing a common bcc Bravais lattice was calculated within the framework of density functional theory. A set of effective cluster interactions was calculated through a cluster expansion (CE) of the total energies. The finite temperature phase diagram of bcc Cu-Al was obtained using the CE formalism coupled with the cluster variation method calculation of the configurational entropy. These results are confronted with a simpler semi-empirical approach based on effective pair interactions obtained from experiment. Both approaches predict a single first-order A2/DO3 transition for compositions close to Cu3Al, in agreement with the most recent experimental results.
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International Nuclear Information System (INIS)
Martin-Gonzalez, M.S.; Briones, F.; Garcia-Martin, J.M.; Montserrat, J.; Vila, L.; Faini, G.; Testa, A.M.; Fiorani, D.; Rohrmann, H.
2010-01-01
Magnetic nano-patterning of perpendicular hard disk media with perpendicular anisotropy, but preserving disk surface planarity, is presented here. Reactive ion implantation is used to locally modify the chemical composition (hence the magnetization and magnetic anisotropy) of the Co/Pd multilayer in irradiated areas. The procedure involves low energy, chemically reactive ion irradiation through a resist mask. Among N, P and As ions, P are shown to be most adequate to obtain optimum bit density and topography flatness for industrial Co/Pd multilayer media. The effect of this ion contributes to isolate perpendicular bits by destroying both anisotropy and magnetic exchange in the irradiated areas. Low ion fluences are effective due to the stabilization of atomic displacement levels by the chemical effect of covalent impurities.
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High strength and utilizable ductility of bulk ultrafine-grained Cu-Al alloys
An, X. H.; Han, W. Z.; Huang, C. X.; Zhang, P.; Yang, G.; Wu, S. D.; Zhang, Z. F.
2008-05-01
Lack of plasticity is the main drawback for nearly all ultrafine-grained (UFG) materials, which restricts their practical applications. Bulk UFG Cu-Al alloys have been fabricated by using equal channel angular pressing technique. Its ductility was improved to exceed the criteria for structural utility while maintaining a high strength by designing the microstructure via alloying. Factors resulting in the simultaneously enhanced strength and ductility of UFG Cu-Al alloys are the formation of deformation twins and their extensive intersections facilitating accumulation of dislocations.
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Ma, Fuliang; Li, Jinlong; Zeng, Zhixiang; Gao, Yimin
2018-01-01
The CrN monolayer and CrN/AlN nano-multilayer coating were successfully fabricated by reactive magnetron sputtering on F690 steel. The results show that CrN monolayer exhibits a face centered cubic crystalline structure with (111) preferred orientation and CrN/AlN nano-multilayer coating has a (200) preferred orientation. This design of the nano-multilayer can interrupt the continuous growth of columnar crystals making the coating denser. The CrN/AlN nano-multilayer coating has a better wear resistance and corrosion resistance compared with the CrN monolayer coating. The tribocorrosion tests reveal that the evolution of potential and current density of F690 steel and CrN monolayer or CrN/AlN nano-multilayer coating see an opposite trend under the simultaneous action of wear and corrosion, which is attributed to that F690 steel is a non-passive material and PVD coatings is a passive material. The nano-multilayer structure has a good ;Pore Sealing Effect;, and the corrosive solution is difficult to pass through the coating to corrode the substrate.
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Carbon and nitrogen co-doping self-assembled MoS{sub 2} multilayer films
Energy Technology Data Exchange (ETDEWEB)
Zhang, Xiaoqin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Xu, Jiao; Chai, Liqiang [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); He, Tengfei [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Yu, Fucheng [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Wang, Peng, E-mail: pengwang@licp.cas.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)
2017-06-01
Highlights: • Mo–S–C–N composite films were synthesized by using reactive magnetron sputtering. • A self-assembled multilayer structure with periodicity in the nanometer scale was formed in the composite film. • The hardness of Mo–S–C–N film deposited at optimized parameter reaches up to 9.76 GPa. • The wear rate of deposited Mo–S–C–N film both in vacuum and ambient atmosphere decreases dramatically. - Abstract: Mo–S–C–N composite films were prepared using reactive magnetron sputtering of graphite and MoS{sub 2} targets in argon and nitrogen atmospheres. The effects of carbon/nitrogen co-doping and carbon concentration on the composition, microstructure, mechanical and tribological properties of deposited films have been investigated by various characterization techniques. The results show that the deposited films comprise MoS{sub 2} nanocrystalline and amorphous carbon, and the incorporating nitrogen forms Mo-N and C–N chemical bonds. Increasing carbon concentration leads to the increase of sp{sup 2} carbon fraction in the films. Furthermore, the high-resolution transmission electron microscopy reveals that a self-assembled multilayer structure with periodicity in the nanometer scale is formed in the Mo–S–C–N film. Benefiting from the composite and self-assembled multilayer structures, the hardness of Mo–S–C–N film deposited at optimized parameter reaches up to 9.76 GPa, and corresponding friction experiment indicates that this composite films display low friction coefficient and high wear resistance both in vacuum and ambient air conditions.
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Dai, Wei; Gao, Xiang; Liu, Jingmao; Kwon, Se-Hun; Wang, Qimin
2017-12-01
Diamond-like carbon (DLC) coatings with AlTiSi multi-doping were prepared by a reactive high power impulse magnetron sputtering with using a gas mixture of Ar and C2H2 as precursor. The composition, microstructure, compressive stress, and mechanical property of the as-deposited DLC coatings were studied systemically by using SEM, XPS, TEM, Raman spectrum, stress-tester, and nanoindentation as a function of the Ar fraction. The results show that the doping concentrations of the Al, Ti and Si atoms increased as the Ar fraction increased. The doped Ti and Si preferred to bond with C while the doped Al mainly existed in oxidation state without bonding with C. As the doping concentrations increased, TiC carbide nanocrystals were formed in the DLC matrix. The microstructure of coatings changed from an amorphous feature dominant AlTiSi-DLC to a carbide nanocomposite AlTiSi-DLC with TiC nanoparticles embedding. In addition, the coatings exhibited the compositionally modulated multilayer consisting of alternate Al-rich layer and Al-poor layer due to the rotation of the substrate holder and the diffusion behavior of the doped Al which tended to separate from C and diffuse towards the DLC matrix surface owing to its weak interactions with C. The periodic Al-rich layer can effectively release the compressive stress of the coatings. On the other hand, the hard TiC nanoparticles were conducive to the hardness of the coatings. Consequently, the DLC coatings with relatively low residual stress and high hardness could be acquired successfully through AlTiSi multi-doping. It is believed that the AlCrSi multi-doping may be a good way for improving the comprehensive properties of the DLC coatings. In addition, we believe that the DLC coatings with Al-rich multilayered structure have a high oxidation resistance, which allows the DLC coatings application in high temperature environment.
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International Nuclear Information System (INIS)
William Grips, V.K.; Barshilia, Harish C.; Selvi, V. Ezhil; Kalavati; Rajam, K.S.
2006-01-01
The corrosion behaviors of single layer TiN, CrN, TiAlN and multilayer TiAlN/CrN coatings, deposited on steel substrate using a multi-target reactive direct current magnetron sputtering process, were studied in 3.5% NaCl solution by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The total thickness of the coatings was about 1.5 μm. About 0.5 μm thick chromium interlayer was used for improved adhesion of the coatings. The potentiodynamic polarization measurements showed that for all the coatings the corrosion potential shifted to higher values as compared to the uncoated substrate. Similarly, the corrosion current density decreased for coated samples, indicating better corrosion resistance of the coated samples. The multilayer coatings of TiAlN/CrN exhibited superior corrosion behavior as compared to the single layer coatings. The Nyquist and the Bode plots obtained from the EIS measurements were fitted by appropriate equivalent circuits to calculate the pore resistance, the charge transfer resistance and the capacitance. These studies revealed that the pore resistance was lowest for TiN coatings, which increased for TiAlN coatings. TiAlN/CrN multilayer coatings exhibited highest pore resistance. No significant change in the capacitive behavior of the coatings was observed, suggesting minimal morphological changes as a result of immersion in the electrolyte. This could be attributed to shorter immersion durations. These studies were confirmed by examining the corroded samples under scanning electron microscope. Preliminary experiments conducted with additional interlayer of electroless nickel (5.0 μm thick) have shown significant improvement in the corrosion resistance of the coatings
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Elemental separation in nanocrystalline Cu-Al alloys
Wang, Y. B.; Liao, X. Z.; Zhao, Y. H.; Cooley, J. C.; Horita, Z.; Zhu, Y. T.
2013-06-01
Nanocrystallization by high-energy severe plastic deformation has been reported to increase the solubility of alloy systems and even to mix immiscible elements to form non-equilibrium solid solutions. In this letter, we report an opposite phenomenon—nanocrystallization of a Cu-Al single-phase solid solution by high-pressure torsion separated Al from the Cu matrix when the grain sizes are refined to tens of nanometers. The Al phase was found to form at the grain boundaries of nanocrystalline Cu. The level of the separation increases with decreasing grain size, which suggests that the elemental separation was caused by the grain size effect.
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Fabrication of multilayer nanowires
Energy Technology Data Exchange (ETDEWEB)
Kaur, Jasveer, E-mail: kaurjasveer89@gmail.com; Singh, Avtar; Kumar, Davinder [Department of Physics, Punjabi University Patiala, 147002, Punjab (India); Thakur, Anup; Kaur, Raminder, E-mail: raminder-k-saini@yahoo.com [Department of Basic and Applied Sciences, Punjabi University Patiala, 147002, Punjab (India)
2016-05-06
Multilayer nanowires were fabricated by potentiostate ectrodeposition template synthesis method into the pores of polycarbonate membrane. In present work layer by layer deposition of two different metals Ni and Cu in polycarbonate membrane having pore size of 600 nm were carried out. It is found that the growth of nanowires is not constant, it varies with deposition time. Scanning electron microscopy (SEM) is used to study the morphology of fabricated multilayer nanowires. An energy dispersive X-ray spectroscopy (EDS) results confirm the composition of multilayer nanowires. The result shows that multilayer nanowires formed is dense.
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Fabrication of multilayer nanowires
International Nuclear Information System (INIS)
Kaur, Jasveer; Singh, Avtar; Kumar, Davinder; Thakur, Anup; Kaur, Raminder
2016-01-01
Multilayer nanowires were fabricated by potentiostate ectrodeposition template synthesis method into the pores of polycarbonate membrane. In present work layer by layer deposition of two different metals Ni and Cu in polycarbonate membrane having pore size of 600 nm were carried out. It is found that the growth of nanowires is not constant, it varies with deposition time. Scanning electron microscopy (SEM) is used to study the morphology of fabricated multilayer nanowires. An energy dispersive X-ray spectroscopy (EDS) results confirm the composition of multilayer nanowires. The result shows that multilayer nanowires formed is dense.
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Mechanochemical synthesis of dodecyl sulfate anion (DS-) intercalated Cu-Al layered double hydroxide
Qu, Jun; He, Xiaoman; Lei, Zhiwu; Zhang, Qiwu; Liu, Xinzhong
2017-12-01
Dodecyl sulfate anion (DS-) was successfully intercalated into the gallery space of Cu-Al layered double hydroxides (LDH) by a non-heating mechanochemical route, in which basic cupric carbonate (Cu2(OH)2CO3) and aluminum hydroxide (Al(OH)3) were first dry ground and then agitated in SDS solution under ambient environment. The organics modified Cu-Al LDH showed good adsorption ability toward 2,4-dichlorophenoxyacetic acid (2, 4-D). The prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), CHS elemental analysis and Scanning electron microscopy (SEM). The LDH precursor prepared by ball-milling could directly react with SDS molecules forming a pure phase of DS- pillared Cu-Al LDH, which was not observed with the LDH product through the ion-exchange of DS- at room temperature. The process introduced here may be applied to manufacture other types of organic modified composites for pollutants removal and other applications.
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International Nuclear Information System (INIS)
Grips, V.K. William; Ezhil Selvi, V.; Barshilia, Harish C.; Rajam, K.S.
2006-01-01
The electrochemical behavior of single layer TiN, CrN, TiAlN and multilayer TiAlN/CrN coatings, deposited on steel substrates using a multi-target reactive direct current (dc) magnetron sputtering process, was studied in 3.5% NaCl solution. The total thickness of the coatings was about 1.5 μm. About 0.5 μm thick chromium interlayer was used to improve adhesion of the coatings. With an aim to improve the corrosion resistance, an additional interlayer of approximately 5 μm thick electroless nickel (EN) was deposited on the substrate. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were used to study the corrosion behavior of the coatings. Scanning electron microscopy and energy dispersive X-ray analysis were used to characterize the corroded samples. The potentiodynamic polarization tests showed lower corrosion current density and higher polarization resistance (R p ) for the coatings with EN interlayer. For example, the corrosion current density of TiN coated steel was decreased by a factor of 10 by incorporating 5 μm thick EN interlayer. Similarly, multilayer coatings of TiAlN/CrN with EN interlayer showed about 30 times improved corrosion resistance as compared to the multilayers without EN interlayer. The porosity values were calculated from the potentiodynamic polarization data. The Nyquist and the Bode plots obtained from the EIS data were fitted by appropriate equivalent circuits. The pore resistance (R pore ), the charge transfer resistance (R ct ), the coating capacitance (Q coat ) and the double layer capacitance (Q dl ) of the coatings were obtained from the equivalent circuit. Multilayer coatings showed higher R pore and R ct values as compared to the single layer coatings. Similarly, the Q coat and Q dl values decreased from uncoated substrate to the multilayer coatings, indicating a decrease in the defect density by the addition of EN interlayer. These studies were confirmed by examining the corroded samples under
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X-ray radiation effects in multilayer epitaxial graphene
Energy Technology Data Exchange (ETDEWEB)
Hicks, Jeremy; Tinkey, Holly; Hankinson, John; Heer, Walt A. de; Conrad, Edward H. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Arora, Rajan; Kenyon, Eleazar; Chakraborty, Partha S.; Cressler, John D. [School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Berger, Claire [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); CNRS-Institut Neel, BP 166, 38042 Grenoble Cedex 9 (France)
2011-12-05
We characterize multilayer graphene grown on C-face SiC before and after exposure to a total ionizing dose of 12 Mrad(SiO{sub 2}) using a 10 keV x-ray source. While we observe the partial peeling of the top graphene layers and the appearance of a modest Raman D-peak, we find that the electrical characteristics (mobility, sheet resistivity, free carrier concentration) of the material are mostly unaffected by radiation exposure. Combined with x-ray photoelectron spectroscopy data showing numerous carbon-oxygen bonds after irradiation, we conclude that the primary damage mechanism is through surface etching from reactive oxygen species created by the x-rays.
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Directory of Open Access Journals (Sweden)
A.V. Demchyshyn
2007-12-01
Full Text Available TiN/ZrN multilayered condensates on BK-8 carbide tips substrates (62 HRC were produced by the vacuumarc deposition technique, using Ti and Zr plasma flows in reactive nitrogen gas medium with working pressure of 6.6·10–1 Pa. The TiN/ZrN multilayered condensates consist of TiN and ZrN sublayers, which have a thickness of ~100 nm, controlled by the processing parameters of the used deposition technique. The obtained coatings have hardness of 45 GPa and Young’s modulus of 320 GPa. The obtained results show that mechanical properties of such multilayered composites are considerably improved in comparison to those for the single-component coatings, TiN and ZrN. The dependence of hardness and Young’s modulus of the composites on sublayer thickness within a range of 100 nm was determined. The investigated structure and improved mechanical properties of the TiN/ZrN multilayered condensates would be very good platform for finding their industrial application, such as hard coatings with different purposes.
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International Nuclear Information System (INIS)
Chu, K.; Lu, Y.H.; Shen, Y.G.
2008-01-01
Nano-multilayers represent a new class of engineering materials that are made up of alternating nanometer scale layers of two different components. In the present work a titanium (Ti) monolayer was combined with titanium diboride (TiB 2 ) to form a Ti/TiB 2 nano-multilayer. Designed experimental parameters enabled an evaluation of the effects of direct current bias voltage (U b ) and bilayer thickness (Λ) during multilayer deposition on the mechanical properties of reactively sputtered Ti/TiB 2 multilayer films. Their nanostructures and mechanical properties were characterized and analyzed using X-ray photoelectron spectroscopy (XPS), low-angle and high-angle X-ray diffraction (XRD), plan-view and cross-sectional high-resolution transmission electron microscopy (HRTEM), and microindentation measurements. Under the optimal bias voltage of U b = - 60 V, it was found that Λ (varied from 1.1 to 9.8 nm) was the most important factor which dominated the nanostructure and hardness. The hardness values obtained varied from 12 GPa for Ti and 15 GPa for TiB 2 monolayers, up to 33 GPa for the hardest Ti/TiB 2 multilayer at Λ = 1.9 nm. The observed hardness enhancement correlated to the layer thickness, followed a relation similar to the Hall-Petch strengthening dependence, with a generalized power of ∼ 0.6. In addition, the structural barriers between two materials (hcp Ti/amorphous TiB 2 ) and stress relaxation at interfaces within multilayer films resulted in a reduction of crack propagation and high-hardness
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Surface acoustic wave devices on AlN/3C–SiC/Si multilayer structures
International Nuclear Information System (INIS)
Lin, Chih-Ming; Lien, Wei-Cheng; Riekkinen, Tommi; Senesky, Debbie G; Pisano, Albert P; Chen, Yung-Yu; Felmetsger, Valery V
2013-01-01
Surface acoustic wave (SAW) propagation characteristics in a multilayer structure including a piezoelectric aluminum nitride (AlN) thin film and an epitaxial cubic silicon carbide (3C–SiC) layer on a silicon (Si) substrate are investigated by theoretical calculation in this work. Alternating current (ac) reactive magnetron sputtering was used to deposit highly c-axis-oriented AlN thin films, showing the full width at half maximum (FWHM) of the rocking curve of 1.36° on epitaxial 3C–SiC layers on Si substrates. In addition, conventional two-port SAW devices were fabricated on the AlN/3C–SiC/Si multilayer structure and SAW propagation properties in the multilayer structure were experimentally investigated. The surface wave in the AlN/3C–SiC/Si multilayer structure exhibits a phase velocity of 5528 m s −1 and an electromechanical coupling coefficient of 0.42%. The results demonstrate the potential of AlN thin films grown on epitaxial 3C–SiC layers to create layered SAW devices with higher phase velocities and larger electromechanical coupling coefficients than SAW devices on an AlN/Si multilayer structure. Moreover, the FWHM values of rocking curves of the AlN thin film and 3C–SiC layer remained constant after annealing for 500 h at 540 °C in air atmosphere. Accordingly, the layered SAW devices based on AlN thin films and 3C–SiC layers are applicable to timing and sensing applications in harsh environments. (paper)
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International Nuclear Information System (INIS)
Kaszuba, John P.; Longmire, Patrick A.; Strietelmeier, Elizabeth A.; Taylor, Tammy P.; Den-Baars, Peter S.
2004-01-01
A multi-layered permeable reactive barrier (PRB) has been installed in Mortandad Canyon, on the Pajarito Plateau in the north-central part of LANL, to demonstrate in-situ treatment of a suite of contaminants with dissimilar geochemical properties. The PRB will also mitigate possible vulnerabilities from downgradient contaminant movement within alluvial and deeper perched groundwater. Mortandad Canyon was selected as the location for this demonstration project because the flow of alluvial groundwater is constrained by the geology of the canyon, a large network of monitoring wells already were installed along the canyon reach, and the hydrochemistry and contaminant history of the canyon is well-documented. The PRB uses a funnel-and-gate system with a series of four reactive media cells to immobilize or destroy contaminants present in alluvial groundwater, including strontium-90, plutonium-238,239,240, americium-241, perchlorate, and nitrate. The four cells, ordered by sequence of contact with the groundwater, consist of gravel-sized scoria (for colloid removal); phosphate rock containing apatite (for metals and radionuclides); pecan shells and cotton seed admixed with gravel (bio-barrier, to deplete dissolved oxygen and destroy potential RCRA organic compounds, nitrate and perchlorate); and limestone (pH buffering and anion adsorption). Design elements of the PRB are based on laboratory-scale treatability studies and on a field investigation of hydrologic, geochemical, and geotechnical parameters. The PRB was designed with the following criteria: 1-day residence time within the biobarrier, 10-year lifetime, minimization of surface water infiltration and erosion, optimization of hydraulic capture, and minimization of excavated material requiring disposal. Each layer has been equipped with monitoring wells or ports to allow sampling of groundwater and reactive media, and monitor wells are located immediately adjacent to the up- and down-gradient perimeter of the
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Enhancement of surface mechanical properties by using TiN[BCN/BN] n/c-BN multilayer system
Moreno, H.; Caicedo, J. C.; Amaya, C.; Muñoz-Saldaña, J.; Yate, L.; Esteve, J.; Prieto, P.
2010-11-01
The aim of this work is to improve the mechanical properties of AISI 4140 steel substrates by using a TiN[BCN/BN] n/c-BN multilayer system as a protective coating. TiN[BCN/BN] n/c-BN multilayered coatings via reactive r.f. magnetron sputtering technique were grown, systematically varying the length period ( Λ) and the number of bilayers ( n) because one bilayer ( n = 1) represents two different layers ( tBCN + tBN), thus the total thickness of the coating and all other growth parameters were maintained constant. The coatings were characterized by Fourier transform infrared spectroscopy showing bands associated with h-BN bonds and c-BN stretching vibrations centered at 1400 cm -1 and 1100 cm -1, respectively. Coating composition and multilayer modulation were studied via secondary ion mass spectroscopy. Atomic force microscopy analysis revealed a reduction in grain size and roughness when the bilayer number ( n) increased and the bilayer period decreased. Finally, enhancement of mechanical properties was determined via nanoindentation measurements. The best behavior was obtained when the bilayer period ( Λ) was 80 nm ( n = 25), yielding the relative highest hardness (˜30 GPa) and elastic modulus (230 GPa). The values for the hardness and elastic modulus are 1.5 and 1.7 times greater than the coating with n = 1, respectively. The enhancement effects in multilayered coatings could be attributed to different mechanisms for layer formation with nanometric thickness due to the Hall-Petch effect; because this effect, originally used to explain increased hardness with decreasing grain size in bulk polycrystalline metals, has also been used to explain hardness enhancements in multilayered coatings taking into account the thickness reduction at individual single layers that make up the multilayered system. The Hall-Petch model based on dislocation motion within layered and across layer interfaces has been successfully applied to multilayered coatings to explain this
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Enhancement of surface mechanical properties by using TiN[BCN/BN]n/c-BN multilayer system
International Nuclear Information System (INIS)
Moreno, H.; Caicedo, J.C.; Amaya, C.; Munoz-Saldana, J.; Yate, L.; Esteve, J.; Prieto, P.
2010-01-01
The aim of this work is to improve the mechanical properties of AISI 4140 steel substrates by using a TiN[BCN/BN] n /c-BN multilayer system as a protective coating. TiN[BCN/BN] n /c-BN multilayered coatings via reactive r.f. magnetron sputtering technique were grown, systematically varying the length period (Λ) and the number of bilayers (n) because one bilayer (n = 1) represents two different layers (t BCN + t BN ), thus the total thickness of the coating and all other growth parameters were maintained constant. The coatings were characterized by Fourier transform infrared spectroscopy showing bands associated with h-BN bonds and c-BN stretching vibrations centered at 1400 cm -1 and 1100 cm -1 , respectively. Coating composition and multilayer modulation were studied via secondary ion mass spectroscopy. Atomic force microscopy analysis revealed a reduction in grain size and roughness when the bilayer number (n) increased and the bilayer period decreased. Finally, enhancement of mechanical properties was determined via nanoindentation measurements. The best behavior was obtained when the bilayer period (Λ) was 80 nm (n = 25), yielding the relative highest hardness (∼30 GPa) and elastic modulus (230 GPa). The values for the hardness and elastic modulus are 1.5 and 1.7 times greater than the coating with n = 1, respectively. The enhancement effects in multilayered coatings could be attributed to different mechanisms for layer formation with nanometric thickness due to the Hall-Petch effect; because this effect, originally used to explain increased hardness with decreasing grain size in bulk polycrystalline metals, has also been used to explain hardness enhancements in multilayered coatings taking into account the thickness reduction at individual single layers that make up the multilayered system. The Hall-Petch model based on dislocation motion within layered and across layer interfaces has been successfully applied to multilayered coatings to explain this
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Facile synthesis of dendritic Cu by electroless reaction of Cu-Al alloys in multiphase solution
Wang, Ying; Liang, Shuhua; Yang, Qing; Wang, Xianhui
2016-11-01
Two-dimensional nano- or micro-scale fractal dendritic coppers (FDCs) were synthesized by electroless immersing of Cu-Al alloys in hydrochloric acid solution containing copper chloride without any assistance of template or surfactant. The FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl2 + HCl solution. Compared to Cu40Al60 and Cu45Al55 alloys, the FDC shows hierarchical distribution and homogeneous structures using Cu17Al83 alloy as the starting alloy. The growth direction of the FDC is , and all angles between the trunks and branches are 60°. Nanoscale Cu2O was found at the edge of FDC. Interestingly, nanoporous copper (NPC) can also be obtained through Cu17Al83 alloy. Studies showed that the formation of FDC depended on two key factors: the potential difference between CuAl2 intermetallic and α-Al phase of dual-phase Cu-Al alloys; a replacement reaction that usually occurs in multiphase solution. The electrochemical experiment further proved that the multi-branch dendritic structure is very beneficial to the proton transfer in the process of catalyzing methanol.
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New developments in Ni/Ti multilayers
Energy Technology Data Exchange (ETDEWEB)
Anderson, I; Hoghoj, P [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)
1997-04-01
It is now 20 years since super-mirrors were first used as a neutron optical element. Since then the field of multilayer neutron-optics has matured with multilayers finding their way to application in many neutron scattering instruments. However, there is still room for progress in terms of multilayer quality, performance and application. Along with work on multilayers for neutron polarisation Ni/Ti super-mirrors have been optimised. The state-of-the-art Ni/Ti super-mirror performance and the results obtained in two neutron-optics applications of Ni/Ti multilayers are presented. (author).
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Neutron optics with multilayer monochromators
International Nuclear Information System (INIS)
Saxena, A.M.; Majkrzak, C.F.
1984-01-01
A multilayer monochromator is made by depositing thin films of two materials in an alternating sequence on a glass substrate. This makes a multilayer periodic in a direction perpendicular to the plane of the films, with a d-spacing equal to the thickness of one bilayer. Neutrons of wavelength λ incident on a multilayer will be reflected at an angle phi given by the Bragg relation nλ = 2d sinphi, where n is the order of reflection. The use of thin-film multilayers for monochromating neutrons is discussed. Because of the low flux of neutrons, the samples have to be large, and the width of the incident beam can be as much as 2 cm. Multilayers made earlier were fabricated by resistive heating of the materials in a vacuum chamber. Because of geometrical constraints imposed by the size of the vacuum chamber, limits on the amount of material that can be loaded in a boat, and finite life of the boats, this method of preparation limits the length of a multilayer to ∼ 15 cm and the total number of bilayers in a multilayer to about 200. This paper discusses a thin-film deposition system using RF sputtering for depositing films
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Feasibility of Using Multilayer Platelets as Toughening Agents
Directory of Open Access Journals (Sweden)
Yuan-Liang Chin
2009-12-01
Full Text Available It is known that the toughness of brittle ceramics can be improved significantly with the addition of hard platelets. In the present study, platelet-shape multilayer ceramic laminates are utilized as a toughening agent for alumina ceramics. They are prepared by laminating the BaTiO3-based ceramic tapes. Although the elastic modulus of the BaTiO3-based platelets is lower than that of the alumina matrix, and the platelets are also reactive to alumina at elevated temperatures, the weak platelets are found to exhibit the ability to deflect major matrix cracks by forming a large number of microcrack branches within the platelets, thus achieving the desired toughening effect.
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Energy Technology Data Exchange (ETDEWEB)
Khabibullin, R. A., E-mail: khabibullin@isvch.ru; Shchavruk, N. V.; Pavlov, A. Yu.; Ponomarev, D. S.; Tomosh, K. N.; Galiev, R. R.; Maltsev, P. P. [Russian Academy of Sciences, Institute of Ultrahigh Frequency Semiconductor Electronics (Russian Federation); Zhukov, A. E.; Cirlin, G. E.; Zubov, F. I.; Alferov, Zh. I. [Russian Academy of Sciences, Saint Petersburg Academic University—Nanotechnology Research and Education Center (Russian Federation)
2016-10-15
The Postgrowth processing of GaAs/AlGaAs multilayer heterostructures for terahertz quantumcascade lasers (QCLs) are studied. This procedure includes the thermocompression bonding of In–Au multilayer heterostructures with a doped n{sup +}-GaAs substrate, mechanical grinding, and selective wet etching of the substrate, and dry etching of QCL ridge mesastripes through a Ti/Au metallization mask 50 and 100 μm wide. Reactive-ion-etching modes with an inductively coupled plasma source in a BCl{sub 3}/Ar gas mixture are selected to obtain vertical walls of the QCL ridge mesastripes with minimum Ti/Au mask sputtering.
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International Nuclear Information System (INIS)
Behrens, Malte; Tomforde, Jan; May, Enno; Kiebach, Ragnar; Bensch, Wolfgang; Haeussler, Dietrich; Jaeger, Wolfgang
2006-01-01
The reactivity of [Cr/Se/Te] multilayers under annealing was investigated using X-ray reflectometry, in situ X-ray diffraction, X-ray absorption fine structure (XAFS) measurements and transmission electron microscopy. For all samples, interdiffusion was complete at temperatures between 100 and 300 deg. C, depending on the repeating tri-layer thickness. A crystalline phase nucleated approximately 20 deg. C above the temperature where interdiffusion was finished. The first crystalline phase in a binary Cr/Te sample was layered CrTe 3 nucleating at 230 deg. C. In ternary samples (Se:Te=0.6-1.2), the low-temperature nucleation of such a layered CrQ 3 (Q=Se, Te) phase is suppressed and instead the phase Cr 2 Q 3 nucleates first. Interestingly, this phase decomposes around 500 deg. C into layered CrQ 3 . In contrast, binary Cr/Se samples form stable amorphous alloys after interdiffusion and Cr 3 Se 4 nucleates around 500 deg. C as the only crystalline phase. Evaluation of the XAFS data of annealed samples yield Se-Cr distances of 2.568(1) and 2.552(1) A for Cr 2 Q 3 and CrQ 3 , respectively. In the latter sample, higher coordination shells around Se are seen accounting for the Se-Te contacts in the structure. - Graphical abstract: The first step of the reaction of elemental Cr/Te/Se-multilayers is the interdiffusion of the elements as evidenced by the decay of the modulation peaks in the low-angle region of the X-ray diffraction patterns. The subsequent growth of Bragg peaks at higher scattering angles indicates crystallization of chromium chalcogenide Cr 2 Te 3- x Se x
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A diffusion-limited reaction model for self-propagating Al/Pt multilayers with quench limits
Kittell, D. E.; Yarrington, C. D.; Hobbs, M. L.; Abere, M. J.; Adams, D. P.
2018-04-01
A diffusion-limited reaction model was calibrated for Al/Pt multilayers ignited on oxidized silicon, sapphire, and tungsten substrates, as well as for some Al/Pt multilayers ignited as free-standing foils. The model was implemented in a finite element analysis code and used to match experimental burn front velocity data collected from several years of testing at Sandia National Laboratories. Moreover, both the simulations and experiments reveal well-defined quench limits in the total Al + Pt layer (i.e., bilayer) thickness. At these limits, the heat generated from atomic diffusion is insufficient to support a self-propagating wave front on top of the substrates. Quench limits for reactive multilayers are seldom reported and are found to depend on the thermal properties of the individual layers. Here, the diffusion-limited reaction model is generalized to allow for temperature- and composition-dependent material properties, phase change, and anisotropic thermal conductivity. Utilizing this increase in model fidelity, excellent overall agreement is shown between the simulations and experimental results with a single calibrated parameter set. However, the burn front velocities of Al/Pt multilayers ignited on tungsten substrates are over-predicted. Possible sources of error are discussed and a higher activation energy (from 41.9 kJ/mol.at. to 47.5 kJ/mol.at.) is shown to bring the simulations into agreement with the velocity data observed on tungsten substrates. This higher activation energy suggests an inhibited diffusion mechanism present at lower heating rates.
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Energy Technology Data Exchange (ETDEWEB)
Sagdeo, P R; Shinde, D D; Misal, J S [Optics and Thin Film Laboratory, Autonagar, BARC-Vizag, Visakhapatnam -530012 (India); Kamble, N M; Tokas, R B; Biswas, A; Poswal, A K; Thakur, S; Bhattacharyya, D; Sahoo, N K; Sabharwal, S C, E-mail: nksahoo@barc.gov.i, E-mail: sahoonk@gmail.co [Spectroscopy Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
2010-02-03
Titania-silica (TiO{sub 2}/SiO{sub 2}) optical multilayer structures have been conventionally deposited by reactive sputtering of metallic targets. In order to overcome the problems of arcing, target poisoning and low deposition rates encountered there, the application of oxide targets was investigated in this work with asymmetric bipolar pulsed dc magnetron sputtering. In order to evaluate the usefulness of this deposition methodology, an electric field optimized Fabry Perot mirror for He-Cd laser ({lambda} = 441.6 nm) spectroscopy was deposited and characterized. For comparison, this mirror was also deposited by the reactive electron beam (EB) evaporation technique. The mirrors developed by the two complementary techniques were investigated for their microstructural and optical reflection properties invoking atomic force microscopy, ellipsometry, grazing incidence reflectometry and spectrophotometry. From these measurements the layer geometry, optical constants, mass density, topography, surface and interface roughness and disorder parameters were evaluated. The microstructural properties and spectral functional characteristics of the pulsed dc sputtered multilayer mirror were found to be distinctively superior to the EB deposited mirror. The knowledge gathered during this study has been utilized to develop a 21-layer high-pass edge filter for radio photoluminescence dosimetry.
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International Nuclear Information System (INIS)
Sagdeo, P R; Shinde, D D; Misal, J S; Kamble, N M; Tokas, R B; Biswas, A; Poswal, A K; Thakur, S; Bhattacharyya, D; Sahoo, N K; Sabharwal, S C
2010-01-01
Titania-silica (TiO 2 /SiO 2 ) optical multilayer structures have been conventionally deposited by reactive sputtering of metallic targets. In order to overcome the problems of arcing, target poisoning and low deposition rates encountered there, the application of oxide targets was investigated in this work with asymmetric bipolar pulsed dc magnetron sputtering. In order to evaluate the usefulness of this deposition methodology, an electric field optimized Fabry Perot mirror for He-Cd laser (λ = 441.6 nm) spectroscopy was deposited and characterized. For comparison, this mirror was also deposited by the reactive electron beam (EB) evaporation technique. The mirrors developed by the two complementary techniques were investigated for their microstructural and optical reflection properties invoking atomic force microscopy, ellipsometry, grazing incidence reflectometry and spectrophotometry. From these measurements the layer geometry, optical constants, mass density, topography, surface and interface roughness and disorder parameters were evaluated. The microstructural properties and spectral functional characteristics of the pulsed dc sputtered multilayer mirror were found to be distinctively superior to the EB deposited mirror. The knowledge gathered during this study has been utilized to develop a 21-layer high-pass edge filter for radio photoluminescence dosimetry.
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International Nuclear Information System (INIS)
Conley, Ray; Liu Chian; Qian Jun; Kewish, Cameron M.; Macrander, Albert T.; Yan Hanfei; Maser, Joerg; Kang, Hyon Chol; Stephenson, G. Brian
2008-01-01
A multilayer Laue lens (MLL) is an x-ray focusing optic fabricated from a multilayer structure consisting of thousands of layers of two different materials produced by thin-film deposition. The sequence of layer thicknesses is controlled to satisfy the Fresnel zone plate law and the multilayer is sectioned to form the optic. An improved MLL geometry can be created by growing each layer with an in-plane thickness gradient to form a wedge, so that every interface makes the correct angle with the incident beam for symmetric Bragg diffraction. The ultimate hard x-ray focusing performance of a wedged MLL has been predicted to be significantly better than that of a nonwedged MLL, giving subnanometer resolution with high efficiency. Here, we describe a method to deposit the multilayer structure needed for an ideal wedged MLL and report our initial deposition results to produce these structures
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Large-area soft x-ray projection lithography using multilayer mirrors structured by RIE
Rahn, Steffen; Kloidt, Andreas; Kleineberg, Ulf; Schmiedeskamp, Bernt; Kadel, Klaus; Schomburg, Werner K.; Hormes, F. J.; Heinzmann, Ulrich
1993-01-01
SXPL (soft X-ray projection lithography) is one of the most promising applications of X-ray reflecting optics using multilayer mirrors. Within our collaboration, such multilayer mirrors were fabricated, characterized, laterally structured and then used as reflection masks in a projecting lithography procedure. Mo/Si-multilayer mirrors were produced by electron beam evaporation in UHV under thermal treatment with an in-situ X-ray controlled thickness in the region of 2d equals 14 nm. The reflectivities measured at normal incidence reached up to 54%. Various surface analysis techniques have been applied in order to characterize and optimize the X-ray mirrors. The multilayers were patterned by reactive ion etching (RIE) with CF(subscript 4), using a photoresist as the etch mask, thus producing X-ray reflection masks. The masks were tested in the synchrotron radiation laboratory of the electron accelerator ELSA at the Physikalisches Institut of Bonn University. A double crystal X-ray monochromator was modified so as to allow about 0.5 cm(superscript 2) of the reflection mask to be illuminated by white synchrotron radiation. The reflected patterns were projected (with an energy of 100 eV) onto the resist (Hoechst AZ PF 514), which was mounted at an average distance of about 7 mm. In the first test-experiments, structure sizes down to 8 micrometers were nicely reproduced over the whole of the exposed area. Smaller structures were distorted by Fresnel-diffraction. The theoretically calculated diffraction images agree very well with the observed images.
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International Nuclear Information System (INIS)
Mitu, B.; Marotta, V.; Orlando, S.
2006-01-01
Multilayered thin films of In 2 O 3 and SnO 2 have been deposited by conventional and RF plasma-assisted reactive pulsed laser ablation, with the aim to evaluate their behaviour as toxic gas sensors. The depositions have been carried out by a frequency doubled Nd-YAG laser (λ = 532 nm, τ = 7 ns) on Si(1 0 0) substrates, in O 2 atmosphere. The thin films have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrical resistance measurements. A comparison of the electrical response of the simple (indium oxide, tin oxide) and multilayered oxides to toxic gas (nitric oxide, NO) has been performed. The influence on the structural and electrical properties of the deposition parameters, such as substrate temperature and RF power is reported
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Facile synthesis of dendritic Cu by electroless reaction of Cu-Al alloys in multiphase solution
Energy Technology Data Exchange (ETDEWEB)
Wang, Ying; Liang, Shuhua, E-mail: liangxaut@gmail.com; Yang, Qing; Wang, Xianhui
2016-11-30
Highlights: • Nano- or micro-scale fractal dendritic copper (FDC) was synthesized by electroless immersing of Cu-Al alloys in CuCl{sub 2} + HCl. • FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl{sub 2} + HCl solution. • Nanoscale Cu{sub 2}O was found at the edge of FDC. Nanoporous copper (NPC) can also be obtained by using Cu{sub 17}Al{sub 83} alloy. • The potential difference between CuAl{sub 2} and α-Al phase and the replacement reaction in multiphase solution are key factors. - Abstract: Two-dimensional nano- or micro-scale fractal dendritic coppers (FDCs) were synthesized by electroless immersing of Cu-Al alloys in hydrochloric acid solution containing copper chloride without any assistance of template or surfactant. The FDC size increases with the increase of Al content in Cu-Al alloys immersed in CuCl{sub 2} + HCl solution. Compared to Cu{sub 40}Al{sub 60} and Cu{sub 45}Al{sub 55} alloys, the FDC shows hierarchical distribution and homogeneous structures using Cu{sub 17}Al{sub 83} alloy as the starting alloy. The growth direction of the FDC is <110>, and all angles between the trunks and branches are 60°. Nanoscale Cu{sub 2}O was found at the edge of FDC. Interestingly, nanoporous copper (NPC) can also be obtained through Cu{sub 17}Al{sub 83} alloy. Studies showed that the formation of FDC depended on two key factors: the potential difference between CuAl{sub 2} intermetallic and α-Al phase of dual-phase Cu-Al alloys; a replacement reaction that usually occurs in multiphase solution. The electrochemical experiment further proved that the multi-branch dendritic structure is very beneficial to the proton transfer in the process of catalyzing methanol.
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Interfacial effects in multilayers
International Nuclear Information System (INIS)
Barbee, T.W. Jr.
1998-01-01
Interfacial structure and the atomic interactions between atoms at interfaces in multilayers or nano-laminates have significant impact on the physical properties of these materials. A technique for the experimental evaluation of interfacial structure and interfacial structure effects is presented and compared to experiment. In this paper the impact of interfacial structure on the performance of x-ray, soft x-ray and extreme ultra-violet multilayer optic structures is emphasized. The paper is concluded with summary of these results and an assessment of their implications relative to multilayer development and the study of buried interfaces in solids in general
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Study of CuAl(100) by using He ion scattering
Energy Technology Data Exchange (ETDEWEB)
Zhu, L; Zur Muhlen, E; O` Connor, D J [Newcastle Univ., NSW (Australia). Dept. of Physics
1994-12-31
The clean CuAl (100) surface has been investigated by using He{sup +} ion scattering. The polar scans show that Al atoms randomly replace the Cu atoms but sit (0.15{+-}0.05) Angstroms higher than the Cu atoms. The outmost layer concentration of Al is about (17{+-}3)%. The aluminium concentration on the outmost layer is sensitive to the sample temperature up to 300 deg C. 7 refs., 5 figs.
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Study of CuAl(100) by using He ion scattering
Energy Technology Data Exchange (ETDEWEB)
Zhu, L.; Zur Muhlen, E.; O`Connor, D.J. [Newcastle Univ., NSW (Australia). Dept. of Physics
1993-12-31
The clean CuAl (100) surface has been investigated by using He{sup +} ion scattering. The polar scans show that Al atoms randomly replace the Cu atoms but sit (0.15{+-}0.05) Angstroms higher than the Cu atoms. The outmost layer concentration of Al is about (17{+-}3)%. The aluminium concentration on the outmost layer is sensitive to the sample temperature up to 300 deg C. 7 refs., 5 figs.
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Energy Technology Data Exchange (ETDEWEB)
Caicedo, J.C., E-mail: jcesarca@calima.univalle.edu.co [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Amaya, C. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Laboratorio de Recubrimientos Duros, CDT-ASTIN SENA, Cali (Colombia); Cabrera, G. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Esteve, J. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Aperador, W. [Universidad Militar Nueva Granada Bogota D.C (Colombia); Gomez, M.E. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Prieto, P. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Centro de Excelencia en Nuevos Materiales, CENM, Calle 13 100-00 Edificio 320, espacio 1026, Cali (Colombia)
2011-07-29
The aim of this work is the improvement of the electrochemical behavior of 4140 steel substrate using TiCN/TiNbCN multilayered system as a protective coating. We have grown [TiCN/TiNbCN]{sub n} multilayered via reactive r.f. magnetron sputtering technique in which was varied systematically the bilayer period ({Lambda}), and the bilayer number (n), maintaining constant the total thickness of the coatings ({approx} 3 {mu}m). The coatings were characterized by X-ray diffraction (XRD), optical microscopy, electron microscopy and transmission electron microscopy assisted with selected area electron diffraction. The electrochemical properties were studied by Electrochemical Impedance Spectroscopy and Tafel curves. XRD results showed a preferential growth in the face-centered cubic (111) crystal structure for [TiCN/TiNbCN]{sub n} multilayered coatings [1]. In this work was obtained the maximum corrosion resistance for the coating with ({Lambda}) equal to 15 nm, corresponding to n = 200 bilayered. The polarization resistance and corrosion rate were around 8.6 kOhm cm{sup 2} and 7.59 . 10{sup -4} mm/year, these values were 8.6 and 0.001 times better than those showed by the uncoated 4140 steel substrate (1.0 kOhm and 0.57 mm/year), respectively. The improvement of the electrochemical behavior of the 4140 coated with this TiCN/TiNbCN multilayered system can be attributed to the presence of several interfaces that act as obstacles for the inward and outward diffusions of Cl{sup -} ion species, generating an increment in the energy or potential required for translating the corrosive ions across the coating/substrate interface. Moreover, the interface systems affect the means free path on the ions toward the metallic substrate, due to the decreasing of the defects presented in the multilayered coatings.
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International Nuclear Information System (INIS)
Caicedo, J.C.; Amaya, C.; Cabrera, G.; Esteve, J.; Aperador, W.; Gomez, M.E.; Prieto, P.
2011-01-01
The aim of this work is the improvement of the electrochemical behavior of 4140 steel substrate using TiCN/TiNbCN multilayered system as a protective coating. We have grown [TiCN/TiNbCN] n multilayered via reactive r.f. magnetron sputtering technique in which was varied systematically the bilayer period (Λ), and the bilayer number (n), maintaining constant the total thickness of the coatings (∼ 3 μm). The coatings were characterized by X-ray diffraction (XRD), optical microscopy, electron microscopy and transmission electron microscopy assisted with selected area electron diffraction. The electrochemical properties were studied by Electrochemical Impedance Spectroscopy and Tafel curves. XRD results showed a preferential growth in the face-centered cubic (111) crystal structure for [TiCN/TiNbCN] n multilayered coatings [1]. In this work was obtained the maximum corrosion resistance for the coating with (Λ) equal to 15 nm, corresponding to n = 200 bilayered. The polarization resistance and corrosion rate were around 8.6 kOhm cm 2 and 7.59 . 10 -4 mm/year, these values were 8.6 and 0.001 times better than those showed by the uncoated 4140 steel substrate (1.0 kOhm and 0.57 mm/year), respectively. The improvement of the electrochemical behavior of the 4140 coated with this TiCN/TiNbCN multilayered system can be attributed to the presence of several interfaces that act as obstacles for the inward and outward diffusions of Cl - ion species, generating an increment in the energy or potential required for translating the corrosive ions across the coating/substrate interface. Moreover, the interface systems affect the means free path on the ions toward the metallic substrate, due to the decreasing of the defects presented in the multilayered coatings.
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Misoriented dislocation substructures and the fracture of polycrystalline Cu-Al alloys
Koneva, N. A.; Trishkina, L. I.; Cherkasova, T. V.; Kozlov, E. V.
2016-10-01
The evolution of the dislocation substructure in polycrystalline Cu-Al alloys with various grain sizes is studied during deformation to failure. A relation between the fracture of the alloys and the forming misorientation dislocation substructures is revealed. Microcracks in the alloy are found to form along grain boundaries and the boundaries of misoriented dislocation cells and microtwins.
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Figure correction of multilayer coated optics
Chapman; Henry N. , Taylor; John S.
2010-02-16
A process is provided for producing near-perfect optical surfaces, for EUV and soft-x-ray optics. The method involves polishing or otherwise figuring the multilayer coating that has been deposited on an optical substrate, in order to correct for errors in the figure of the substrate and coating. A method such as ion-beam milling is used to remove material from the multilayer coating by an amount that varies in a specified way across the substrate. The phase of the EUV light that is reflected from the multilayer will be affected by the amount of multilayer material removed, but this effect will be reduced by a factor of 1-n as compared with height variations of the substrate, where n is the average refractive index of the multilayer.
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Sectioning of multilayers to make a multilayer Laue lens
International Nuclear Information System (INIS)
Kang, Hyon Chol; Stephenson, G. Brian; Liu Chian; Conley, Ray; Khachatryan, Ruben; Wieczorek, Michael; Macrander, Albert T.; Yan Hanfei; Maser, Joerg; Hiller, Jon; Koritala, Rachel
2007-01-01
We report a process to fabricate multilayer Laue lenses (MLL's) by sectioning and thinning multilayer films. This method can produce a linear zone plate structure with a very large ratio of zone depth to width (e.g., >1000), orders of magnitude larger than can be attained with photolithography. Consequently, MLL's are advantageous for efficient nanofocusing of hard x rays. MLL structures prepared by the technique reported here have been tested at an x-ray energy of 19.5 keV, and a diffraction-limited performance was observed. The present article reports the fabrication techniques that were used to make the MLL's
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Finding overlapping communities in multilayer networks.
Liu, Weiyi; Suzumura, Toyotaro; Ji, Hongyu; Hu, Guangmin
2018-01-01
Finding communities in multilayer networks is a vital step in understanding the structure and dynamics of these layers, where each layer represents a particular type of relationship between nodes in the natural world. However, most community discovery methods for multilayer networks may ignore the interplay between layers or the unique topological structure in a layer. Moreover, most of them can only detect non-overlapping communities. In this paper, we propose a new community discovery method for multilayer networks, which leverages the interplay between layers and the unique topology in a layer to reveal overlapping communities. Through a comprehensive analysis of edge behaviors within and across layers, we first calculate the similarities for edges from the same layer and the cross layers. Then, by leveraging these similarities, we can construct a dendrogram for the multilayer networks that takes both the unique topological structure and the important interplay into consideration. Finally, by introducing a new community density metric for multilayer networks, we can cut the dendrogram to get the overlapping communities for these layers. By applying our method on both synthetic and real-world datasets, we demonstrate that our method has an accurate performance in discovering overlapping communities in multilayer networks.
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Controlling light with plasmonic multilayers
DEFF Research Database (Denmark)
Orlov, Alexey A.; Zhukovsky, Sergei; Iorsh, Ivan V.
2014-01-01
metamaterials and describe their use for light manipulation at the nanoscale. While demonstrating the recently emphasized hallmark effect of hyperbolic dispersion, we put special emphasis to the comparison between multilayered hyperbolic metamaterials and more broadly defined plasmonic-multilayer metamaterials...
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Enhancement of surface mechanical properties by using TiN[BCN/BN]{sub n}/c-BN multilayer system
Energy Technology Data Exchange (ETDEWEB)
Moreno, H. [Laboratorio de Recubrimientos Duros, CDT-ASTIN SENA, Cali (Colombia); Caicedo, J.C., E-mail: Jcesarca@calima.univalle.edu.co [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Amaya, C. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Munoz-Saldana, J. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Queretaro, Mexico (Mexico); Yate, L.; Esteve, J. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Prieto, P. [Grupo de Peliculas Delgadas, Universidad del Valle, Cali (Colombia); Centro de Excelencia en Nuevos Materiales, CENM, Cali (Colombia)
2010-11-15
The aim of this work is to improve the mechanical properties of AISI 4140 steel substrates by using a TiN[BCN/BN]{sub n}/c-BN multilayer system as a protective coating. TiN[BCN/BN]{sub n}/c-BN multilayered coatings via reactive r.f. magnetron sputtering technique were grown, systematically varying the length period ({Lambda}) and the number of bilayers (n) because one bilayer (n = 1) represents two different layers (t{sub BCN} + t{sub BN}), thus the total thickness of the coating and all other growth parameters were maintained constant. The coatings were characterized by Fourier transform infrared spectroscopy showing bands associated with h-BN bonds and c-BN stretching vibrations centered at 1400 cm{sup -1} and 1100 cm{sup -1}, respectively. Coating composition and multilayer modulation were studied via secondary ion mass spectroscopy. Atomic force microscopy analysis revealed a reduction in grain size and roughness when the bilayer number (n) increased and the bilayer period decreased. Finally, enhancement of mechanical properties was determined via nanoindentation measurements. The best behavior was obtained when the bilayer period ({Lambda}) was 80 nm (n = 25), yielding the relative highest hardness ({approx}30 GPa) and elastic modulus (230 GPa). The values for the hardness and elastic modulus are 1.5 and 1.7 times greater than the coating with n = 1, respectively. The enhancement effects in multilayered coatings could be attributed to different mechanisms for layer formation with nanometric thickness due to the Hall-Petch effect; because this effect, originally used to explain increased hardness with decreasing grain size in bulk polycrystalline metals, has also been used to explain hardness enhancements in multilayered coatings taking into account the thickness reduction at individual single layers that make up the multilayered system. The Hall-Petch model based on dislocation motion within layered and across layer interfaces has been successfully applied to
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Interfacial behaviour of biopolymer multilayers
Corstens, Meinou N.; Osorio Caltenco, Lilia A.; Vries, de Renko; Schroën, Karin; Berton-Carabin, Claire C.
2017-01-01
Although multilayered emulsions have been related to reduced lipolysis, the involved interfacial phenomena have never been studied directly. In this work, we systematically built multilayers of whey protein and pectin, which we further subjected to digestive conditions, using two different
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Multilayer TiC/TiN diffusion barrier films for copper
International Nuclear Information System (INIS)
Yoganand, S.N.; Raghuveer, M.S.; Jagannadham, K.; Wu, L.; Karoui, A.; Rozgonyi, G.
2002-01-01
TiC/TiN thin films deposited by reactive magnetron sputtering on Si (100) substrates were investigated by transmission electron microscopy for microstructure and by deep level transient spectroscopy (DLTS) for diffusion barrier against copper. TiN thin films deposited on Si substrates at a substrate temperature of 600 deg. C were textured, and TiC thin films deposited at the same temperature were polycrystalline. TiC/TiN multilayer films also showed the same characteristics with the formation of an additional interaction layer. The diffusion barrier characteristics of the TiC/TiN/Si were determined by DLTS and the results showed that the films completely prevented diffusion of copper into Si
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A refined model for characterizing x-ray multilayers
International Nuclear Information System (INIS)
Oren, A.L.; Henke, B.L.
1987-12-01
The ability to quickly and accurately characterize arbitrary multilayers is very valuable for not only can we use the characterizations to predict the reflectivity of a multilayer for any soft x-ray wavelength, we also can generalize the results to apply to other multilayers of the same type. In addition, we can use the characterizations as a means of evaluating various sputtering environments and refining sputtering techniques to obtain better multilayers. In this report we have obtained improved characterizations for sample molybdenum-silicon and vanadium-silicon multilayers. However, we only examined five crystals overall, so the conclusions that we could draw about the structure of general multilayers is limited. Research involving many multilayers manufactured under the same sputtering conditions is clearly in order. In order to best understand multilayer structures it may be necessary to further refine our model, e.g., adopting a Gaussian form for the interface regions. With such improvements we can expect even better agreement with experimental values and continued concurrence with other characterization techniques. 18 refs., 30 figs., 7 tabs
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Multi-Layer E-Textile Circuits
Dunne, Lucy E.; Bibeau, Kaila; Mulligan, Lucie; Frith, Ashton; Simon, Cory
2012-01-01
Stitched e-textile circuits facilitate wearable, flexible, comfortable wearable technology. However, while stitched methods of e-textile circuits are common, multi-layer circuit creation remains a challenge. Here, we present methods of stitched multi-layer circuit creation using accessible tools and techniques.
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Base Metal Co-Fired Multilayer Piezoelectrics
Directory of Open Access Journals (Sweden)
Lisheng Gao
2016-03-01
Full Text Available Piezoelectrics have been widely used in different kinds of applications, from the automobile industry to consumer electronics. The novel multilayer piezoelectrics, which are inspired by multilayer ceramic capacitors, not only minimize the size of the functional parts, but also maximize energy efficiency. Development of multilayer piezoelectric devices is at a significant crossroads on the way to achieving low costs, high efficiency, and excellent reliability. Concerning the costs of manufacturing multilayer piezoelectrics, the trend is to replace the costly noble metal internal electrodes with base metal materials. This paper discusses the materials development of metal co-firing and the progress of integrating current base metal chemistries. There are some significant considerations in metal co-firing multilayer piezoelectrics: retaining stoichiometry with volatile Pb and alkaline elements in ceramics, the selection of appropriate sintering agents to lower the sintering temperature with minimum impact on piezoelectric performance, and designing effective binder formulation for low pO2 burnout to prevent oxidation of Ni and Cu base metal.
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International Nuclear Information System (INIS)
Skliarova, Hanna; Renzelli, Marco; Azzolini, Oscar; Felicis, Daniele de; Bemporad, Edoardo; Johnson, Richard R.; Palmieri, Vincenzo
2015-01-01
Chemically inert coatings on Havar"® entrance foils of the targets for ["1"8F] production via proton irradiation of enriched water at pressurized conditions are needed to decrease the amount of ionic contaminants released from Havar"®. During current investigation, magnetron sputtered niobium and niobium oxide were chosen as the candidates for protective coatings because of their superior chemical resistance. Aluminated quartz substrates allowed us to verify the protection efficiency of the desirable coatings as diffusion barriers. Two modeling corrosion tests based on the extreme susceptibility of aluminum to liquid gallium and acid corrosion were applied. As far as niobium coatings obtained by magnetron sputtering are columnar, the grain boundaries provide a fast diffusion path for active species of corrosive media to penetrate and to corrode the substrate. Amorphous niobium oxide films obtained by reactive magnetron sputtering showed superior barrier properties according to the corrosion tests performed. In order to prevent degrading of brittle niobium oxide at high pressures, multilayers combining high ductility of niobium with superior diffusion barrier efficiency of niobium oxide were proposed. The intercalation of niobium oxide interlayers was proved to interrupt the columnar grain growth of niobium during sputtering, resulting in improved diffusion barrier efficiency of obtained multilayers. The thin layer multilayer coating architecture with 70 nm bi-layer thickness was found preferential because of higher thermal stability. - Highlights: • Diffusion barrier efficiency of niobium, niobium oxide and their multilayers was studied. • The intercalation of niobium oxide layers interrupted the columnar grain growth of niobium. • The bilayer architectures influenced the stability of the multilayer coatings. • The thin layer multilayer coating with 70 nm double-layer was found superior.
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International Nuclear Information System (INIS)
Schier, V.
1995-12-01
Novel multilayer coatings with metallic and covalent layer materials were prepared by magnetron sputtering and characterised concerning structure, properties and application behaviour. At first single layer coatings were deposited for the determination of the material properties. To evaluate relations between structure and properties of the multilayer coatings, different multilayer concepts were realised: - coatings consisting of at most 7 layers of metallic hard materials, - 100-layer coatings consisting of metallic and covalent hard materials, - TiN-TiC multilayer coatings with different numbers of layers (between 10 and 1000), - 150-layer coatings, based on TiN-TiC multilayers, with thin ( 4 C, AlN, SiC, a:C, Si 3 N 4 , SiAlON). X-rays and electron microscopic analysis indicate in spite of nonstoichiometric compositions single phase crystalline structures for nonreactively and reactively sputtered metastable single layer Ti(B,C)-, Ti(B,N)- and Ti(B,C,N)-coatings. These single layer coatings show excellent mechanical properties (e.g. hardness values up to 6000 HV0,05), caused by lattice stresses as well as by atomic bonding conditions similar to those in c:BN and B 4 C. The good tribological properties shown in pin-on-disk-tests can be attributed to the very high hardness of the coatings. The coatings consisting of at most 7 layers of metallic hard materials show good results mainly for the cutting of steel Ck45, due to the improved mechanical properties (e.g. hardness, toughness) of the multilayers compared to the single layer coatings. This improvement is caused by inserting the hard layer materials and the coherent reinforcement of the coatings. (orig.)
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Energy Technology Data Exchange (ETDEWEB)
Skliarova, Hanna, E-mail: Hanna.Skliarova@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell' Università, 2, 35020 Legnaro, Padua (Italy); University of Ferrara, Ferrara (Italy); Renzelli, Marco, E-mail: marco.renzelli@uniroma3.it [University of Rome “Roma TRE”, Via della Vasca Navale, 79, 00146 Rome (Italy); Azzolini, Oscar, E-mail: Oscar.Azzolini@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell' Università, 2, 35020 Legnaro, Padua (Italy); Felicis, Daniele de, E-mail: daniele.defelicis@uniroma3.it [University of Rome “Roma TRE”, Via della Vasca Navale, 79, 00146 Rome (Italy); Bemporad, Edoardo, E-mail: edoardo.bemporad@uniroma3.it [University of Rome “Roma TRE”, Via della Vasca Navale, 79, 00146 Rome (Italy); Johnson, Richard R., E-mail: richard.johnson@teambest.com [BEST Cyclotron Systems Inc., 8765 Ash Street Unit 7, Vancouver BC V6P 6T3 (Canada); Palmieri, Vincenzo, E-mail: Vincenzo.Palmieri@lnl.infn.it [National Institute of Nuclear Physics, Legnaro National Laboratories, Viale dell' Università, 2, 35020 Legnaro, Padua (Italy); University of Padua, Padua (Italy)
2015-09-30
Chemically inert coatings on Havar{sup ®} entrance foils of the targets for [{sup 18}F] production via proton irradiation of enriched water at pressurized conditions are needed to decrease the amount of ionic contaminants released from Havar{sup ®}. During current investigation, magnetron sputtered niobium and niobium oxide were chosen as the candidates for protective coatings because of their superior chemical resistance. Aluminated quartz substrates allowed us to verify the protection efficiency of the desirable coatings as diffusion barriers. Two modeling corrosion tests based on the extreme susceptibility of aluminum to liquid gallium and acid corrosion were applied. As far as niobium coatings obtained by magnetron sputtering are columnar, the grain boundaries provide a fast diffusion path for active species of corrosive media to penetrate and to corrode the substrate. Amorphous niobium oxide films obtained by reactive magnetron sputtering showed superior barrier properties according to the corrosion tests performed. In order to prevent degrading of brittle niobium oxide at high pressures, multilayers combining high ductility of niobium with superior diffusion barrier efficiency of niobium oxide were proposed. The intercalation of niobium oxide interlayers was proved to interrupt the columnar grain growth of niobium during sputtering, resulting in improved diffusion barrier efficiency of obtained multilayers. The thin layer multilayer coating architecture with 70 nm bi-layer thickness was found preferential because of higher thermal stability. - Highlights: • Diffusion barrier efficiency of niobium, niobium oxide and their multilayers was studied. • The intercalation of niobium oxide layers interrupted the columnar grain growth of niobium. • The bilayer architectures influenced the stability of the multilayer coatings. • The thin layer multilayer coating with 70 nm double-layer was found superior.
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Multilayer Stochastic Block Models Reveal the Multilayer Structure of Complex Networks
Directory of Open Access Journals (Sweden)
Toni Vallès-Català
2016-03-01
Full Text Available In complex systems, the network of interactions we observe between systems components is the aggregate of the interactions that occur through different mechanisms or layers. Recent studies reveal that the existence of multiple interaction layers can have a dramatic impact in the dynamical processes occurring on these systems. However, these studies assume that the interactions between systems components in each one of the layers are known, while typically for real-world systems we do not have that information. Here, we address the issue of uncovering the different interaction layers from aggregate data by introducing multilayer stochastic block models (SBMs, a generalization of single-layer SBMs that considers different mechanisms of layer aggregation. First, we find the complete probabilistic solution to the problem of finding the optimal multilayer SBM for a given aggregate-observed network. Because this solution is computationally intractable, we propose an approximation that enables us to verify that multilayer SBMs are more predictive of network structure in real-world complex systems.
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Multilayer Nanoporous Graphene Membranes for Water Desalination.
Cohen-Tanugi, David; Lin, Li-Chiang; Grossman, Jeffrey C
2016-02-10
While single-layer nanoporous graphene (NPG) has shown promise as a reverse osmosis (RO) desalination membrane, multilayer graphene membranes can be synthesized more economically than the single-layer material. In this work, we build upon the knowledge gained to date toward single-layer graphene to explore how multilayer NPG might serve as a RO membrane in water desalination using classical molecular dynamic simulations. We show that, while multilayer NPG exhibits similarly promising desalination properties to single-layer membranes, their separation performance can be designed by manipulating various configurational variables in the multilayer case. This work establishes an atomic-level understanding of the effects of additional NPG layers, layer separation, and pore alignment on desalination performance, providing useful guidelines for the design of multilayer NPG membranes.
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Mechanical properties of highly textured Cu/Ni multilayers
International Nuclear Information System (INIS)
Liu, Y.; Bufford, D.; Wang, H.; Sun, C.; Zhang, X.
2011-01-01
We report on the synthesis of highly (1 1 1) and (1 0 0) textured Cu/Ni multilayers with individual layer thicknesses, h, varying from 1 to 200 nm. When, h, decreases to 5 nm or less, X-ray diffraction spectra show epitaxial growth of Cu/Ni multilayers. High resolution transmission electron microscopy studies show the coexistence of nanotwins and coherent layer interfaces in highly (1 1 1) textured Cu/Ni multilayers with smaller h. Hardnesses of multilayer films increase with decreasing h, approach a maximum at h of a few nanometers, and show softening thereafter at smaller h. The influence of layer interfaces as well as twin interfaces on strengthening mechanisms of multilayers and the formation of twins in Ni in multilayers are discussed.
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Investigations on Cu-Ni and Cu-Al systems with secondary ion mass spectrometry (SIMS)
International Nuclear Information System (INIS)
Rodriguez-Murcia, H.; Beske, H.E.
1976-04-01
The ratio of the ionization coefficients of secondary atomic ions emitted from the two component systems Cu-Ni and Cu-Al was investigated as a function of the concentration of the two components. In the low concentration range the ratio of the ionization coefficients is a constant. An influence of the phase composition on the ratio of the ionization coefficients was found in the Cu-Al system. In addition, the cluster ion emission was investigated as a function of the concentration and the phase composition of the samples. The secondary atomic ion intensity was influenced by the presence of cluster ions. The importance of the cluster ions in quantitative analysis and phase determination by means of secondary ion mass spectrometry are discussed. (orig.) [de
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Extended asymmetric-cut multilayer X-ray gratings.
Prasciolu, Mauro; Haase, Anton; Scholze, Frank; Chapman, Henry N; Bajt, Saša
2015-06-15
The fabrication and characterization of a large-area high-dispersion blazed grating for soft X-rays based on an asymmetric-cut multilayer structure is reported. An asymmetric-cut multilayer structure acts as a perfect blazed grating of high efficiency that exhibits a single diffracted order, as described by dynamical diffraction throughout the depth of the layered structure. The maximum number of grating periods created by cutting a multilayer deposited on a flat substrate is equal to the number of layers deposited, which limits the size of the grating. The size limitation was overcome by depositing the multilayer onto a substrate which itself is a coarse blazed grating and then polish it flat to reveal the uniformly spaced layers of the multilayer. The number of deposited layers required is such that the multilayer thickness exceeds the step height of the substrate structure. The method is demonstrated by fabricating a 27,060 line pairs per mm blazed grating (36.95 nm period) that is repeated every 3,200 periods by the 120-μm period substrate structure. This preparation technique also relaxes the requirements on stress control and interface roughness of the multilayer film. The dispersion and efficiency of the grating is demonstrated for soft X-rays of 13.2 nm wavelength.
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Soft X-ray multilayers and filters
Wang Zhan Shan; Tang Wei Xing; Qin Shuji; Zhou Bing; Chen Ling Ya
2002-01-01
The periodic and non-periodic multilayers were designed by using a random number to change each layer and a suitable merit function. Ion beam sputtering and magnetron sputtering were used to fabricate various multilayers and beam splitters in soft X-ray range. The characterization of multilayers by small angle X-ray diffraction, Auger electron spectroscopy, Rutherford back scattering spectroscopy and reflectivity illustrated the multilayers had good structures and smooth interlayers. The reflectivity and transmission of a beam splitter is about 5%. The fabrication and transmission properties of Ag, Zr were studied. The Rutherford back scattering spectroscopy and auger electron spectroscopy were used to investigate the contents and distributions of impurities and influence on qualities of filters. The attenuation coefficients were corrected by the data obtained by measurements
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Characterization of new multilayered composites for photovoltaic systems
Energy Technology Data Exchange (ETDEWEB)
Weps, M.; Kretzschmar, T. [Fraunhofer Institute for Mechanics of Materials, Halle (Saale) (Germany)
2010-07-01
The reduction of manufacturing costs and efficient usage of materials have highest priority in the solar industry and are a prerequisite for its further positive development. Common aluminum framed modules and double glass modules have a series of disadvantages. In context of a group project a new construction variant of lightweight photovoltaic modules and its realization with efficient manufacturing technologies is currently developed. An essential component of these new photovoltaic modules is an injection molded frame of fiber reinforced plastics. It serves to absorb mechanical loads caused by wind and snow loads. Thus, the usual aluminum frames can be omitted. Additionally, the stiff construction of the plastic frame allows the substitution of the glass pane by a lightweight plastic pane. The coupling between plastic frame and pane is achieved by a transparent chemical reactive system in which the solar cells are embedded. The characterization of this material combination is executed on multilayered composites. The used types of plastics for frame and pane are in the form of plates and glued together in a special tool. The adhesion between the layers is evaluated by different test methods and FEM-models. In this case the compression shear test plays an important role. An especially developed device is used to evaluate shear behavior of the multilayered composites. Based on the carried out tests statements about effects of surface modification of the plastic pane are given. (orig.)
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Generalized planar fault energies and twinning in Cu-Al alloys
Kibey, S.; Liu, J. B.; Johnson, D. D.; Sehitoglu, H.
2006-11-01
We report ab initio density functional theory calculations of generalized planar fault energies of fcc Cu -xAl (x =0, 5.0, and 8.3at.%) alloys. We investigate the effects of substitutional solute Al on the unstable intrinsic γus and twin γut stacking fault energies (SFEs). Our results reveal an increased tendency of Cu-Al to deform preferentially by twinning with increasing Al content, consistent with experiment. We attribute this mechanical behavior to appreciable lowering of the twinning barrier γut, along with the stable intrinsic and twin SFEs.
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Mechanical properties of intermetallics formed during thermal aging of Cu-Al ball bonds
Kouters, M.H.M.; Gubbels, G.H.M.; O'Halloran, O.; Rongen, R.; Weltevreden, E.R.
2011-01-01
In high power automotive electronics copper wire bonding is regarded as most promising alternative for gold wire bonding in 1st level interconnects and therefore subjected to severe functional requirements. In the Cu-Al ball bond interface the growth of intermetallic compounds may deteriorate the
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Magnetoresistive multilayers deposited on the AAO membranes
International Nuclear Information System (INIS)
Malkinski, Leszek M.; Chalastaras, Athanasios; Vovk, Andriy; Jung, Jin-Seung; Kim, Eun-Mee; Jun, Jong-Ho; Ventrice, Carl A.
2005-01-01
Silicon and GaAs wafers are the most commonly used substrates for deposition of giant magnetoresistive (GMR) multilayers. We explored a new type of a substrate, prepared electrochemically by anodization of aluminum sheets, for deposition of GMR multilayers. The surface of this AAO substrate consists of nanosized hemispheres organized in a regular hexagonal array. The current applied along the substrate surface intersects many magnetic layers in the multilayered structure, which results in enhancement of giant magnetoresistance effect. The GMR effect in uncoupled Co/Cu multilayers was significantly larger than the magnetoresistance of similar structures deposited on Si
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Heat stability evaluations of Co/SiO2 multilayers
International Nuclear Information System (INIS)
Ishino, Masahiko; Koike, Masato; Kanehira, Mika; Satou, Futami; Terauchi, Masami; Sano, Kazuo
2008-01-01
The heat stability of Co/SiO 2 multilayers was evaluated. Co/SiO 2 multilayer samples were deposited on Si substrate by means of an ion beam sputtering method, and annealed at temperatures from 100degC to 600degC in a vacuum furnace. For the structural and optical evaluations, small angle x-ray diffraction (XRD) measurements, soft x-ray reflectivity measurements, and transmission electron microscopy (TEM) observations were carried out. As the results, the Co/SiO 2 multilayer samples annealed up to 400degC maintained the initial multilayer structures, and kept almost the same soft x-ray reflectivities as that of the as-deposited Co/SiO 2 multilayer sample. A deterioration of the multilayer structure caused by the growth of Co grains was found on the Co/SiO 2 multilayer samples annealed over 500degC, and the soft x-ray reflectivity dropped in accordance with the deterioration of the multilayer structure. (author)
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Reeve, Kathlene N.; Anderson, Iver E.; Handwerker, Carol A.
2015-03-01
Lead-free solder alloys Sn-Cu (SC) and Sn-Ag-Cu (SAC) are widely used by the microelectronics industry, but enhanced control of the microstructure is needed to improve solder performance. For such control, nucleation and stability of Cu-Al intermetallic compound (IMC) solidification catalysts were investigated by variation of the Cu (0.7-3.0 wt.%) and Al (0.0-0.4 wt.%) content of SC + Al and SAC + Al alloys, and of SAC + Al ball-grid array (BGA) solder joints. All of the Al-modified alloys produced Cu-Al IMC particles with different morphologies and phases (occasionally non-equilibrium phases). A trend of increasing Cu-Al IMC volume fraction with increasing Al content was established. Because of solidification of non-equilibrium phases in wire alloy structures, differential scanning calorimetry (DSC) experiments revealed delayed, non-equilibrium melting at high temperatures related to quenched-in Cu-Al phases; a final liquidus of 960-1200°C was recorded. During cooling from 1200°C, the DSC samples had the solidification behavior expected from thermodynamic equilibrium calculations. Solidification of the ternary alloys commenced with formation of ternary β and Cu-Al δ phases at 450-550°C; this was followed by β-Sn, and, finally, Cu6Sn5 and Cu-Al γ1. Because of the presence of the retained, high-temperature phases in the alloys, particle size and volume fraction of the room temperature Cu-Al IMC phases were observed to increase when the alloy casting temperature was reduced from 1200°C to 800°C, even though both temperatures are above the calculated liquidus temperature of the alloys. Preliminary electron backscatter diffraction results seemed to show Sn grain refinement in the SAC + Al BGA alloy.
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Numerical simulation and experiment on multilayer stagger-split die.
Liu, Zhiwei; Li, Mingzhe; Han, Qigang; Yang, Yunfei; Wang, Bolong; Sui, Zhou
2013-05-01
A novel ultra-high pressure device, multilayer stagger-split die, has been constructed based on the principle of "dividing dies before cracking." Multilayer stagger-split die includes an encircling ring and multilayer assemblages, and the mating surfaces of the multilayer assemblages are mutually staggered between adjacent layers. In this paper, we investigated the stressing features of this structure through finite element techniques, and the results were compared with those of the belt type die and single split die. The contrast experiments were also carried out to test the bearing pressure performance of multilayer stagger-split die. It is concluded that the stress distributions are reasonable and the materials are utilized effectively for multilayer stagger-split die. And experiments indicate that the multilayer stagger-split die can bear the greatest pressure.
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Energy Technology Data Exchange (ETDEWEB)
Zengin, Adem [Department of Chemistry, Faculty of Art and Science, Gazi University, 06500 Besevler, Ankara (Turkey); Caykara, Tuncer, E-mail: caykara@gazi.edu.tr [Department of Chemistry, Faculty of Art and Science, Gazi University, 06500 Besevler, Ankara (Turkey)
2011-01-01
In this study, we have fabricated a multilayer system consisting of 3-glycidoxypropyldimethylmethoxysilane (GPDS), poly(dimethylsiloxane) bis 3-aminopropyl terminated (PDMS) and protein-A on a silicon wafer surface for oriented immobilization of immunoglobilin G (IgG). The multilayer system with a different component in each layer was characterized by ellipsometry, contact-angle goniometer, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) and fluorescence microscopy. The epoxy-terminated monolayer was formed by the chemisorption of GPDS molecules on the hydroxylated silicon surface. The PDMS film about 4.5 nm thick was produced on the GPDS-monolayer by the chemical reaction between the amine groups at the end of PDMS chain and the epoxy groups of GPDS molecules. By introducing the PDMS chains, the hydrophilic character of GPDS-monolayer decreased. Study of the time dependence of polymer grafting showed that the chemisorption of GPDS is fast, whereas at least 16 h is needed to generate the homogeneous PDMS layer. For immobilization of IgG molecules in a highly oriented manner, protein-A molecules were first chemically bound to an ultrathin ({approx}4.5 nm) PDMS reactive polymer layer and later used to capture IgG. It was shown that the existence of protein-A in the multilayer system has a strong influence on the binding properties of IgG not only in the efficiency of binding, but also in its specificity. In conclusion, the multilayer system with protein-A has the potential to be further developed into an efficient immunoassay protein chip.
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EUV multilayer mirrors with enhanced stability
Benoit, Nicolas; Yulin, Sergiy; Feigl, Torsten; Kaiser, Norbert
2006-08-01
The application of multilayer optics in EUV lithography requires not only the highest possible normal-incidence reflectivity but also a long-term thermal and radiation stability at operating temperatures. This requirement is most important in the case of the collector mirror of the illumination system close to the EUV source where a short-time decrease in reflectivity is most likely. Mo/Si multilayer mirrors, designed for high normal reflectivity at the wavelength of 13.5 nm and deposited by dc magnetron sputtering, were directly exposed to EUV radiation without mitigation system. They presented a loss of reflectivity of more than 18% after only 8 hours of irradiation by a Xe-discharge source. Another problem of Mo/Si multilayers is the instability of reflectivity and peak wavelength under high heat load. It becomes especially critical at temperatures above 200°C, where interdiffusion between the molybdenum and the silicon layers is observed. The development of high-temperature multilayers was focused on two alternative Si-based systems: MoSi II/Si and interface engineered Mo/C/Si/C multilayer mirrors. The multilayer designs as well as the deposition parameters of all systems were optimized in terms of high peak reflectivity (>= 60 %) at a wavelength of 13.5 nm and high thermal stability. Small thermally induced changes of the MoSi II/Si multilayer properties were found but they were independent of the annealing time at all temperatures examined. A wavelength shift of -1.7% and a reflectivity drop of 1.0% have been found after annealing at 500°C for 100 hours. The total degradation of optical properties above 650°C can be explained by a recrystallization process of MoSi II layers.
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Magnetic surfaces, thin films, and multilayers
International Nuclear Information System (INIS)
Parkin, S.S.P.; Renard, J.P.; Shinjo, T.; Zinn, W.
1992-01-01
This paper details recent developments in the magnetism of surfaces, thin films and multilayers. More than 20 invited contributions and more than 60 contributed papers attest to the great interest and vitality of this subject. In recent years the study of magnetic surfaces, thin films and multilayers has undergone a renaissance, partly motivated by the development of new growth and characterization techniques, but perhaps more so by the discovery of many exciting new properties, some quite unanticipated. These include, most recently, the discovery of enormous values of magnetoresistance in magnetic multilayers far exceeding those found in magnetic single layer films and the discovery of oscillatory interlayer coupling in transition metal multilayers. These experimental studies have motivated much theoretical work. However these developments are to a large extent powered by materials engineering and our ability to control and understand the growth of thin layers just a few atoms thick. The preparation of single crystal thin film layers and multilayers remains important for many studies, in particular, for properties dependent. These studies obviously require engineering not just a layer thicknesses but of lateral dimensions as well. The properties of such structures are already proving to be a great interest
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Compositionally Graded Multilayer Ceramic Capacitors.
Song, Hyun-Cheol; Zhou, Jie E; Maurya, Deepam; Yan, Yongke; Wang, Yu U; Priya, Shashank
2017-09-27
Multilayer ceramic capacitors (MLCC) are widely used in consumer electronics. Here, we provide a transformative method for achieving high dielectric response and tunability over a wide temperature range through design of compositionally graded multilayer (CGML) architecture. Compositionally graded MLCCs were found to exhibit enhanced dielectric tunability (70%) along with small dielectric losses (filters and power converters.
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Nondestructive diagnosis of multilayer electronic plates
International Nuclear Information System (INIS)
Matvienko, A.N.; Savin, D.O.; Yas'ko, A.V.
1992-01-01
Methods of non-destructive tomographic investigation into multilayer printed plates using x radiation are described. Mathematic problem setting is given, experimental facility and methods for source data ecquisition are described. A special attention is paid to the consideration of the main factors differing the actual problem setting from the idealized one. Methods for accounting and correction of these factors are described. The efficiency of the approach proposed is demonstrated using the actual problems of reducing separate layers of multilayer printed plate metallization. The method developed is useful when exersizing control over multilayer printed plate production
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Energy Technology Data Exchange (ETDEWEB)
Garralaga Rojas, Enrique; Hensen, Jan; Brendel, Rolf [Institut fuer Solarenergieforschung Hameln (ISFH), Emmerthal (Germany); Carstensen, Juergen; Foell, Helmut [Chair for General Materials Science, Faculty of Engineering, Christian-Albrechts-University of Kiel (Germany)
2011-06-15
We present the reproducible fabrication of porous germanium (PGe) single- and multilayers. Mesoporous layers form on heavily doped 4'' p-type Ge wafers by electrochemical etching in highly concentrated HF-based electrolytes with concentrations in a range of 30-50 wt.%. Direct PGe formation is accompanied by a constant dissolution of the already-formed porous layer at the electrolyte/PGe interface, hence yielding a thinner substrate after etching. This effect inhibits multilayer formation as the starting layer is etched while forming the second layer. We avoid dissolution of the porous layer by alternating the etching bias from anodic to cathodic. PGe formation occurs during anodic etching whereas the cathodic step passivates pore walls with H-atoms and avoids electropolishing. The passivation lasts a limited time depending on the etching current density and electrolyte concentration, necessitating a repetition of the cathodic step at suitable intervals. With optimized alternating bias mesoporous multilayer production is possible. We control the porosity of each single layer by varying the etching current density and the electrolyte (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
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75 FR 79019 - Multilayered Wood Flooring From China
2010-12-17
...)] Multilayered Wood Flooring From China Determinations On the basis of the record \\1\\ developed in the subject... imports from China of multilayered wood flooring, provided for in subheadings 4409.10, 4409.29, 4412.31... multilayered wood flooring. The following companies are members of the CAHP: Anderson Hardwood Floors, LLC...
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Energy Technology Data Exchange (ETDEWEB)
Abedini, Alam; Larki, Farhad; Saion, Elias; Noroozi, Monir [Putra Malaysia Univ., Serdang, Selangor (Malaysia). Dept. of Physics
2013-07-15
Cu-Al bimetallic nanoparticles were synthesized by gamma irradiation technique in aqueous solutions containing metal chlorides as precursors, polyvinyl alcohol (PVA) as a capping agent, isopropanol as a radical scavenger, and distilled water as a solvent. The Cu-Al bimetallic nanoparticles were characterized by transmission electron microscopy (TEM), UV-visible absorption spectrometry, powder X-ray diffractometer (XRD), and Energy-dispersive X-ray spectroscopy (EDX). The TEM, XRD, EDX, and absorption analyses confirmed the formation of core-shell structure of Cu-Al bimetallic nanoparticles at lower Cu{sup 2+}/Al{sup 3+} mole ratio, and the formation of Cu-Al alloy nanoparticles at higher Cu{sup 2+}/Al{sup 3+} mole ratio. The TEM analysis for particle size and size distribution revealed that the average particle size of Cu-Al bimetallic nanoparticles decreased with the increase of absorbed dose. It may be explained due to the competition between nucleation and aggregation processes in the formation of metallic nanoparticles under irradiation. (orig.)
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Wolter type I x-ray focusing mirror using multilayer coatings
International Nuclear Information System (INIS)
Chon, Kwon Su; Namba, Yoshiharu; Yoon, Kwon-Ha
2006-01-01
A multilayer coating is a useful addition to a mirror in the x-ray region and has been applied to normal incidence mirrors used with soft x rays. When a multilayer coating is used on grazing incidence optics, higher performance can be achieved than without it.Cr/Sc multilayers coated on a Wolter type I mirror substrate for a soft x-ray microscope are considered. The reflectivity and effective solid angle are calculated for Wolter type I mirrors with uniform and laterally graded multilayer coatings. The laterally graded multilayer mirror showed superior x-ray performance, and the multilayer tolerances were relaxed. This multilayer mirror could be especially useful in the soft x-ray microscope intended for biological applications
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Irradiated multilayer film for primal meat packaging
International Nuclear Information System (INIS)
Lustig, S.; Schuetz, J.M.; Vicik, S.J.
1987-01-01
This patent deals with a heat-shrinkable, multilayer film suitable for use in fabricating bags for packaging primal and sub-primal meat cuts and processed meats. The multilayer film has a first outer layer of an ethylene-vinyl acetate copolymer, a core layer of a barrier film comprising vinylidene chloride-methyl acrylate copolymer, and a second outer layer of an ethylene-vinyl acetate copolymer. The multilayer film is preferably made by co-extrusion of the layers, and then it is biaxially stretched. After biaxial stretching, the multilayer film is irradiated to a dosage level of between 1 megarad and 5 megarads and heat-sealed in the form of a bag. The bag has improved storage stability characteristics
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Spectral tailoring of nanoscale EUV and soft x-ray multilayer optics
Huang, Qiushi; Medvedev, Viacheslav; van de Kruijs, Robbert; Yakshin, Andrey; Louis, Eric; Bijkerk, Fred
2017-03-01
Extreme ultraviolet and soft X-ray (XUV) multilayer optics have experienced significant development over the past few years, particularly on controlling the spectral characteristics of light for advanced applications like EUV photolithography, space observation, and accelerator- or lab-based XUV experiments. Both planar and three dimensional multilayer structures have been developed to tailor the spectral response in a wide wavelength range. For the planar multilayer optics, different layered schemes are explored. Stacks of periodic multilayers and capping layers are demonstrated to achieve multi-channel reflection or suppression of the reflective properties. Aperiodic multilayer structures enable broadband reflection both in angles and wavelengths, with the possibility of polarization control. The broad wavelength band multilayer is also used to shape attosecond pulses for the study of ultrafast phenomena. Narrowband multilayer monochromators are delivered to bridge the resolution gap between crystals and regular multilayers. High spectral purity multilayers with innovated anti-reflection structures are shown to select spectrally clean XUV radiation from broadband X-ray sources, especially the plasma sources for EUV lithography. Significant progress is also made in the three dimensional multilayer optics, i.e., combining micro- and nanostructures with multilayers, in order to provide new freedom to tune the spectral response. Several kinds of multilayer gratings, including multilayer coated gratings, sliced multilayer gratings, and lamellar multilayer gratings are being pursued for high resolution and high efficiency XUV spectrometers/monochromators, with their advantages and disadvantages, respectively. Multilayer diffraction optics are also developed for spectral purity enhancement. New structures like gratings, zone plates, and pyramids that obtain full suppression of the unwanted radiation and high XUV reflectance are reviewed. Based on the present achievement
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Multilayer Graphene for Waveguide Terahertz Modulator
DEFF Research Database (Denmark)
Khromova, I.; Andryieuski, Andrei; Lavrinenko, Andrei
2014-01-01
We study terahertz to infrared electromagnetic properties of multilayer graphene/dielectric artificial medium and present a novel concept of terahertz modulation at midinfrared wavelengths. This approach allows the realization of high-speed electrically controllable terahertz modulators based...... on hollow waveguide sections filled with multilayer graphene....
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The silicon-silicon oxide multilayers utilization as intrinsic layer on pin solar cells
International Nuclear Information System (INIS)
Colder, H.; Marie, P.; Gourbilleau, F.
2008-01-01
Silicon nanostructures are promising candidate for the intrinsic layer on pin solar cells. In this work we report on new material: silicon-rich silicon oxide (SRSO) deposited by reactive magnetron sputtering of a pure silica target and an interesting structure: multilayers consisting of a stack of SRSO and pure silicon oxide layers. Two thicknesses of the SRSO sublayer, t SRSO , are studied 3 nm and 5 nm whereas the thickness of silica sublayer is maintaining at 3 nm. The presence of nanocrystallites of silicon, evidenced by X-Ray diffraction (XRD), leads to photoluminescence (PL) emission at room temperature due to the quantum confinement of the carriers. The PL peak shifts from 1.3 eV to 1.5 eV is correlated to the decreasing of t SRSO from 5 nm down to 3 nm. In the purpose of their potential utilization for i-layer, the optical properties are studied by absorption spectroscopy. The achievement a such structures at promising absorption properties. Moreover by favouring the carriers injection by the tunnel effect between silicon nanograins and silica sublayers, the multilayers seem to be interesting for solar cells
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An X-ray grazing incidence phase multilayer grating
Chernov, V A; Mytnichenko, S V
2001-01-01
An X-ray grazing incidence phase multilayer grating, representing a thin grating placed on a multilayer mirror, is proposed. A high efficiency of grating diffraction can be obtained by the possibility of changing the phase shift of the wave diffracted from the multilayer under the Bragg and total external reflection conditions. A grazing incidence phase multilayer grating consisting of Pt grating stripes on a Ni/C multilayer and optimized for the hard X-ray range was fabricated. Its diffraction properties were studied at photon energies of 7 and 8 keV. The obtained maximum value of the diffraction efficiency of the +1 grating order was 9% at 7 keV and 6.5% at 8 keV. The data obtained are in a rather good accordance with the theory.
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Exposure of metallic copper surface on Cu-Al2O3-carbon catalysts
Menon, P.G.; Prasad, J.
1970-01-01
The bifunctional nature of Cu---Al2O3-on-carbon catalysts, used in the direct catalytic conversion of ethanol to ethyl acetate, prompted an examination of the dispersion of Cu on the composite catalyst. For this, the N2O-method of Osinga et al. for estimation of bare metallic copper surface on
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Chemical vapor deposition of Si/SiC nano-multilayer thin films
International Nuclear Information System (INIS)
Weber, A.; Remfort, R.; Woehrl, N.; Assenmacher, W.; Schulz, S.
2015-01-01
Stoichiometric SiC films were deposited with the commercially available single source precursor Et_3SiH by classical thermal chemical vapor deposition (CVD) as well as plasma-enhanced CVD at low temperatures in the absence of any other reactive gases. Temperature-variable deposition studies revealed that polycrystalline films containing different SiC polytypes with a Si to carbon ratio of close to 1:1 are formed at 1000 °C in thermal CVD process and below 100 °C in the plasma-enhanced CVD process. The plasma enhanced CVD process enables the reduction of residual stress in the deposited films and offers the deposition on temperature sensitive substrates in the future. In both deposition processes the film thickness can be controlled by variation of the process parameters such as the substrate temperature and the deposition time. The resulting material films were characterized with respect to their chemical composition and their crystallinity using scanning electron microscope, energy dispersive X-ray spectroscopy (XRD), atomic force microscopy, X-ray diffraction, grazing incidence X-ray diffraction, secondary ion mass spectrometry and Raman spectroscopy. Finally, Si/SiC multilayers of up to 10 individual layers of equal thickness (about 450 nm) were deposited at 1000 °C using Et_3SiH and SiH_4. The resulting multilayers features amorphous SiC films alternating with Si films, which feature larger crystals up to 300 nm size as measured by transmission electron microscopy as well as by XRD. XRD features three distinct peaks for Si(111), Si(220) and Si(311). - Highlights: • Stoichiometric silicon carbide films were deposited from a single source precursor. • Thermal as well as plasma-enhanced chemical vapor deposition was used. • Films morphology, crystallinity and chemical composition were characterized. • Silicon/silicon carbide multilayers of up to 10 individual nano-layers were deposited.
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Superconductivity in multilayer perovskite. Weak coupling analysis
International Nuclear Information System (INIS)
Koikegami, Shigeru; Yanagisawa, Takashi
2006-01-01
We investigate the superconductivity of a three-dimensional d-p model with a multilayer perovskite structure on the basis of the second-order perturbation theory within the weak coupling framework. Our model has been designed with multilayer high-T c superconducting cuprates in mind. In our model, multiple Fermi surfaces appear, and the component of a superconducting gap function develops on each band. We have found that the multilayer structure can stabilize the superconductivity in a wide doping range. (author)
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International Nuclear Information System (INIS)
Bansal, R.C.
2008-01-01
This paper presents an artificial neural network (ANN) based approach to tune the parameters of the static var compensator (SVC) reactive power controller over a wide range of typical load model parameters. The gains of PI (proportional integral) based SVC are optimised for typical values of the load voltage characteristics (n q ) by conventional techniques. Using the generated data, the method of multi-layer feed forward ANN with error back propagation training is employed to tune the parameters of the SVC. An ANN tuned SVC controller has been applied to control the reactive power of a variable slip/speed isolated wind-diesel hybrid power system. It is observed that the maximum deviations of all parameters are more for larger values of n q . It has been shown that initially synchronous generator supplies the reactive power required by the induction generator and/or load, and the latter reactive power is purely supplied by the SVC
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Energy Technology Data Exchange (ETDEWEB)
Bansal, R.C. [Electrical and Electronics Engineering Division, School of Engineering and Physics, The University of the South Pacific, Suva (Fiji)
2008-02-15
This paper presents an artificial neural network (ANN) based approach to tune the parameters of the static var compensator (SVC) reactive power controller over a wide range of typical load model parameters. The gains of PI (proportional integral) based SVC are optimised for typical values of the load voltage characteristics (n{sub q}) by conventional techniques. Using the generated data, the method of multi-layer feed forward ANN with error back propagation training is employed to tune the parameters of the SVC. An ANN tuned SVC controller has been applied to control the reactive power of a variable slip/speed isolated wind-diesel hybrid power system. It is observed that the maximum deviations of all parameters are more for larger values of n{sub q}. It has been shown that initially synchronous generator supplies the reactive power required by the induction generator and/or load, and the latter reactive power is purely supplied by the SVC. (author)
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The characterization of multilayers analyzers: Models and measurements
International Nuclear Information System (INIS)
Henke, B.L.; Vejio, J.Y.; Tackaberry, R.E.; Yamada, H.T.
1985-01-01
A procedure is described for the detailed characterization of multilayer analyzers which can be effectively applied to their design, optimization and application for absolute x-ray spectrometry. An accurate analytical model has been developed that is based upon a simple modification of the dynamical Darwin-Prins theory to extend its application to finite multilayer systems. Its equivalence to the optical E and M solution of the Fresnel equations at each interface is demonstrated by detailed calculation comparisons for the reflectivity of a multilayer throughout the angular range of incidence of 0 to 90 0 . A special spectrograph and experimental method is described for the measurement of the absolute reflectivity characteristics of the multilayer. The experimental measurements at three photon energies in the 100-200 eV region are fit by the analytical modified Darwin-Prins equation (MDP) for I(θ), generating a detailed characterization of two ''state of the art'' multilayers, a sputtered tungsten-carbon of 2d ≅ 70 A and a molecular lead separate of 2d ≅ 100 A. The fitting parameters that are determined in this procedure are applied to help establish the structural characteristics of the particular multilayer
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Water surface coverage effects on reactivity of plasma oxidized Ti films
International Nuclear Information System (INIS)
Pranevicius, L.; Pranevicius, L.L.; Vilkinis, P.; Baltaragis, S.; Gedvilas, K.
2014-01-01
Highlights: • The reactivity of Ti films immersed in water vapor plasma depends on the surface water coverage. • The adsorbed water monolayers are disintegrated into atomic constituents on the hydrophilic TiO 2 under plasma radiation. • The TiO 2 surface covered by water multilayer loses its ability to split adsorbed water molecules under plasma radiation. - Abstract: The behavior of the adsorbed water on the surface of thin sputter deposited Ti films maintained at room temperature was investigated in dependence on the thickness of the resulting adsorbed water layer, controllably injecting water vapor into plasma. The surface morphology and microstructure were used to characterize the surfaces of plasma treated titanium films. Presented experimental results showed that titanium films immersed in water vapor plasma at pressure of 10–100 Pa promoted the photocatalytic activity of overall water splitting. The surfaces of plasma oxidized titanium covered by an adsorbed hydroxyl-rich island structure water layer and activated by plasma radiation became highly chemically reactive. As water vapor pressure increased up to 300–500 Pa, the formed water multilayer diminished the water oxidation and, consequently, water splitting efficiency decreased. Analysis of the experimental results gave important insights into the role an adsorbed water layer on surface of titanium exposed to water vapor plasma on its chemical activity and plasma activated electrochemical processes, and elucidated the surface reactions that could lead to the split of water molecules
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Ordered organic-organic multilayer growth
Forrest, Stephen R; Lunt, Richard R
2015-01-13
An ordered multilayer crystalline organic thin film structure is formed by depositing at least two layers of thin film crystalline organic materials successively wherein the at least two thin film layers are selected to have their surface energies within .+-.50% of each other, and preferably within .+-.15% of each other, whereby every thin film layer within the multilayer crystalline organic thin film structure exhibit a quasi-epitaxial relationship with the adjacent crystalline organic thin film.
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Localization of multilayer networks by optimized single-layer rewiring.
Jalan, Sarika; Pradhan, Priodyuti
2018-04-01
We study localization properties of principal eigenvectors (PEVs) of multilayer networks (MNs). Starting with a multilayer network corresponding to a delocalized PEV, we rewire the network edges using an optimization technique such that the PEV of the rewired multilayer network becomes more localized. The framework allows us to scrutinize structural and spectral properties of the networks at various localization points during the rewiring process. We show that rewiring only one layer is enough to attain a MN having a highly localized PEV. Our investigation reveals that a single edge rewiring of the optimized MN can lead to the complete delocalization of a highly localized PEV. This sensitivity in the localization behavior of PEVs is accompanied with the second largest eigenvalue lying very close to the largest one. This observation opens an avenue to gain a deeper insight into the origin of PEV localization of networks. Furthermore, analysis of multilayer networks constructed using real-world social and biological data shows that the localization properties of these real-world multilayer networks are in good agreement with the simulation results for the model multilayer network. This paper is relevant to applications that require understanding propagation of perturbation in multilayer networks.
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Neutron diffraction studies of thin film multilayer structures
International Nuclear Information System (INIS)
Majkrzak, C.F.
1985-01-01
The application of neutron diffraction methods to the study of the microscopic chemical and magnetic structures of thin film multilayers is reviewed. Multilayer diffraction phenomena are described in general and in particular for the case in which one of the materials of a bilayer is ferromagnetic and the neutron beam polarized. Recent neutron diffraction measurements performed on some interesting multilayer systems are discussed. 70 refs., 5 figs
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Design and fabrication of heat resistant multilayers
International Nuclear Information System (INIS)
Thorne, J.M.; Knight, L.V.; Peterson, B.G.; Perkins, R.T.; Gray, K.J.
1986-01-01
Many promising applications of multilayer x-ray optical elements subject them to intense radiation. This paper discusses the selection of optimal pairs of materials to resist heat damage and presents simulations of multilayer performance under extreme heat loadings
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Refractive index contrast in porous silicon multilayers
Energy Technology Data Exchange (ETDEWEB)
Nava, R.; Mora, M.B. de la; Tagueena-Martinez, J. [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Temixco, Morelos (Mexico); Rio, J.A. del [Centro de Investigacion en Energia, Universidad Nacional Autonoma de Mexico, Temixco, Morelos (Mexico); Centro Morelense de Innovacion y Transferencia Tecnologica, Consejo de Ciencia y Tecnologia del Estado de Morelos (Mexico)
2009-07-15
Two of the most important properties of a porous silicon multilayer for photonic applications are flat interfaces and a relative large refractive index contrast between layers in the optical wavelength range. In this work, we studied the effect of the current density and HF electrolyte concentration on the refractive index of porous silicon. With the purpose of increasing the refractive index contrast in a multilayer, the refractive index of porous silicon produced at low current was studied in detail. The current density applied to produce the low porosity layers was limited in order to keep the electrolyte flow through the multilayer structure and to avoid deformation of layer interfaces. We found that an electrolyte composed of hydrofluoric acid, ethanol and glycerin in a ratio of 3:7:1 gives a refractive index contrast around 1.3/2.8 at 600 nm. Several multilayer structures with this refractive index contrast were fabricated, such as dielectric Bragg mirrors and microcavities. Reflectance spectra of the structures show the photonic quality of porous silicon multilayers produced under these electrochemical conditions. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
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Advances in polyelectrolyte multilayer nanofilms as tunable drug delivery systems
Jiang, Bingbing; Barnett, John B; Li, Bingyun
2009-01-01
There has been considerable interest in polyelectrolyte multilayer nanofilms, which have a variety of applications ranging from optical and electrochemical materials to biomedical devices. Polyelectrolyte multilayer nanofilms are constructed from aqueous solutions using electrostatic layer-by-layer self-assembly of oppositely-charged polyelectrolytes on a solid substrate. Multifunctional polyelectrolyte multilayer nanofilms have been studied using charged dyes, metal and inorganic nanoparticles, DNA, proteins, and viruses. In the past few years, there has been increasing attention to developing polyelectrolyte multilayer nanofilms as drug delivery vehicles. In this mini-review, we present recent developments in polyelectrolyte multilayer nanofilms with tunable drug delivery properties, with particular emphasis on the strategies in tuning the loading and release of drugs in polyelectrolyte multilayer nanofilms as well as their applications. PMID:24198464
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Multilayer Spectral Graph Clustering via Convex Layer Aggregation: Theory and Algorithms
Chen, Pin-Yu; Hero, Alfred O.
2017-01-01
Multilayer graphs are commonly used for representing different relations between entities and handling heterogeneous data processing tasks. Non-standard multilayer graph clustering methods are needed for assigning clusters to a common multilayer node set and for combining information from each layer. This paper presents a multilayer spectral graph clustering (SGC) framework that performs convex layer aggregation. Under a multilayer signal plus noise model, we provide a phase transition analys...
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Giorgetti, C.; Collettini, C.; Scuderi, M. M.; Barchi, M. R.; Tesei, T.
2016-12-01
Sealing layers are often represented by sedimentary sequences characterized by alternating strong and weak lithologies. When involved in faulting processes, these mechanically heterogeneous multilayers develop complex fault geometries. Here we investigate fault initiation and evolution within a mechanical multilayer by integrating field observations and rock deformation experiments. Faults initiate with a staircase trajectory that partially reflects the mechanical properties of the involved lithologies, as suggested by our deformation experiments. However, some faults initiating at low angles in calcite-rich layers (θi = 5°-20°) and at high angles in clay-rich layers (θi = 45°-86°) indicate the important role of structural inheritance at the onset of faulting. With increasing displacement, faults develop well-organized fault cores characterized by a marly, foliated matrix embedding fragments of limestone. The angles of fault reactivation, which concentrate between 30° and 60°, are consistent with the low friction coefficient measured during our experiments on marls (μs = 0.39), indicating that clay minerals exert a main control on fault mechanics. Moreover, our integrated analysis suggests that fracturing and faulting are the main mechanisms allowing fluid circulation within the low-permeability multilayer, and that its sealing integrity can be compromised only by the activity of larger faults cutting across its entire thickness.
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Desktop aligner for fabrication of multilayer microfluidic devices.
Li, Xiang; Yu, Zeta Tak For; Geraldo, Dalton; Weng, Shinuo; Alve, Nitesh; Dun, Wu; Kini, Akshay; Patel, Karan; Shu, Roberto; Zhang, Feng; Li, Gang; Jin, Qinghui; Fu, Jianping
2015-07-01
Multilayer assembly is a commonly used technique to construct multilayer polydimethylsiloxane (PDMS)-based microfluidic devices with complex 3D architecture and connectivity for large-scale microfluidic integration. Accurate alignment of structure features on different PDMS layers before their permanent bonding is critical in determining the yield and quality of assembled multilayer microfluidic devices. Herein, we report a custom-built desktop aligner capable of both local and global alignments of PDMS layers covering a broad size range. Two digital microscopes were incorporated into the aligner design to allow accurate global alignment of PDMS structures up to 4 in. in diameter. Both local and global alignment accuracies of the desktop aligner were determined to be about 20 μm cm(-1). To demonstrate its utility for fabrication of integrated multilayer PDMS microfluidic devices, we applied the desktop aligner to achieve accurate alignment of different functional PDMS layers in multilayer microfluidics including an organs-on-chips device as well as a microfluidic device integrated with vertical passages connecting channels located in different PDMS layers. Owing to its convenient operation, high accuracy, low cost, light weight, and portability, the desktop aligner is useful for microfluidic researchers to achieve rapid and accurate alignment for generating multilayer PDMS microfluidic devices.
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Asynchronous cracking with dissimilar paths in multilayer graphene.
Jang, Bongkyun; Kim, Byungwoon; Kim, Jae-Hyun; Lee, Hak-Joo; Sumigawa, Takashi; Kitamura, Takayuki
2017-11-16
Multilayer graphene consists of a stack of single-atomic-thick monolayer graphene sheets bound with π-π interactions and is a fascinating model material opening up a new field of fracture mechanics. In this study, fracture behavior of single-crystalline multilayer graphene was investigated using an in situ mode I fracture test under a scanning electron microscope, and abnormal crack propagation in multilayer graphene was identified for the first time. The fracture toughness of graphene was determined from the measured load-displacement curves and the realistic finite element modelling of specimen geometries. Nonlinear fracture behavior of the multilayer graphene is discussed based on nonlinear elastic fracture mechanics. In situ scanning electron microscope images obtained during the fracture test showed asynchronous crack propagation along independent paths, causing interlayer shear stress and slippages. We also found that energy dissipation by interlayer slippages between the graphene layers is the reason for the enhanced fracture toughness of multilayer graphene. The asynchronous cracking with independent paths is a unique cracking and toughening mechanism for single-crystalline multilayer graphene, which is not observed for the monolayer graphene. This could provide a useful insight for the design and development of graphene-based composite materials for structural applications.
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Recycling of Polymer-Based Multilayer Packaging: A Review
Directory of Open Access Journals (Sweden)
Katharina Kaiser
2017-12-01
Full Text Available Polymer-based multilayer packaging materials are commonly used in order to combine the respective performance of different polymers. By this approach, the tailored functionality of packaging concepts is created to sufficiently protect sensitive food products and thus obtain extended shelf life. However, because of their poor recyclability, most multilayers are usually incinerated or landfilled, counteracting the efforts towards a circular economy and crude oil independency. This review depicts the current state of the European multilayer packaging market and sketches the current end-of-life situation of postconsumer multilayer packaging waste in Germany. In the main section, a general overview of the state of research about material recycling of different multilayer packaging systems is provided. It is divided into two subsections, whereby one describes methods to achieve a separation of the different components, either by delamination or the selective dissolution–reprecipitation technique, and the other describes methods to achieve recycling by compatibilization of nonmiscible polymer types. While compatibilization methods and the technique of dissolution–reprecipitation are already extensively studied, the delamination of packaging has not been investigated systematically. All the presented options are able to recycle multilayer packaging, but also have drawbacks like a limited scope or a high expenditure of energy.
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Robust giant magnetoresistive effect type multilayer sensor
Lenssen, K.M.H.; Kuiper, A.E.T.; Roozeboom, F.
2002-01-01
A robust Giant Magneto Resistive effect type multilayer sensor comprising a free and a pinned ferromagnetic layer, which can withstand high temperatures and strong magnetic fields as required in automotive applications. The GMR multi-layer has an asymmetric magneto-resistive curve and enables
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Irradiated multilayer film for primal meat packaging
International Nuclear Information System (INIS)
Lustig, S.; Schuetz, J.M.; Vicik, S.J.
1987-01-01
This patent deals with a heat-shrinkable, multilayer film suitable for use in fabricating bags for packaging primal and sub-primal meat cuts and processed meats. The multilayer film has a first outer layer of a first ethylene-vinyl acetate copolymer, a core layer of a polyvinylidene chloride-vinyl chloride copolymer containing between about 70 weight percent and about 90 weight percent vinylidene chloride as a barrier film, and a second outer layer of a second ethylene-vinyl acetate copolymer. The multilayer film is preferably made by co-extrusion of the layers, and then it is biaxially stretched. After biaxial stretching, the entire multilayer film is substantially uniformly irradiated to a dosage level of between about 2 megarads and about 3 megarads and heat-sealed in the form of a bag. The film is not significantly discoloured by the irradiation and the bag has improved toughness properties and heat-sealing characteristics
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Dislocation Substructures Formed After Fracture of Deformed Polycrystalline Cu-Al Alloys
Koneva, N. A.; Trishkina, L. I.; Cherkasova, T. V.
2017-08-01
The paper deals with the dislocation substructure of polycrystalline FCC alloys modified by plastic deformation at a distance from the area of the specimen fracture. Observations are performed using the transmission electron microscopy. Cu-Al alloys with grain size ranging from 10 to 240 μm are studied in this paper. The parameters of the dislocation substructure are measured and their variation is determined by the increasing distance from the fracture area. It is shown how the grain size influences these processes. The different dislocation substructures which determine the specimen fracture at a mesocscale level are found herein.
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International Nuclear Information System (INIS)
Huang, Zhenying; Bonneville, Joel; Zhai, Hongxiang; Gauthier-Brunet, Veronique
2014-01-01
Highlights: • Submicro-layered TiC 0.61 /Cu(Al) nanocomposite. • MAX phase. • High yield stress. • Deformation mechanism. - Abstract: A new submicro-layered TiC 0.61 /Cu(Al) composite has been prepared by hot-pressing a mixture of 50 vol.% Ti 3 AlC 2 and 50 vol.% Cu powders at 1150 °C and 30 MPa. It is shown that the initial reinforcement Ti 3 AlC 2 particles have, after synthesis, an unusual microstructure, which consists of submicron-thick layers of TiC 0.61 and Cu(Al) alloy. Both the width of the TiC 0.61 and Cu(Al) layers are ∼150 nm. Thus, the Ti 3 AlC 2 particles are decomposed into the TiC 0.61 phase, while the additional Al atoms provided by Ti 3 AlC 2 diffuse into the molten Cu matrix at high temperature. Compression tests were performed at constant strain rate in the temperature range 20–800 °C. The new designed TiC 0.61 /Cu(Al) composite has both a high yield stress, σ 0.2 measured at 0.2% strain offset, and a high ultimate compressive strength, σ UCS , which is attributed to strong interface bonding between TiC 0.61 and Cu(Al) phase. For instance, at 20 and 200 °C, σ 0.2 is 770 MPa and 700 MPa, while σ UCS is 1.18 GPa and 1 GPa, respectively. Plastic deformation takes place in the Cu(Al) matrix. Wavy slip lines are observed indicating that cross-slip could be the dominant deformation mechanism
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Transfer matrices for multilayer structures
International Nuclear Information System (INIS)
Baquero, R.
1988-08-01
We consider four of the transfer matrices defined to deal with multilayer structures. We deduce algorithms to calculate them numerically, in a simple and neat way. We illustrate their application to semi-infinite systems using SGFM formulae. These algorithms are of fast convergence and allow a calculation of bulk-, surface- and inner-layers band structure in good agreement with much more sophisticated calculations. Supermatrices, interfaces and multilayer structures can be calculated in this way with a small computational effort. (author). 10 refs
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Polymerization of vinyl stearate multilayers by electron beam irradiation
International Nuclear Information System (INIS)
Nishii, Masanobu; Hatada, Motoyoshi
1975-01-01
Studies on the radiation-induced polymerization of vinyl stearate (VST) multilayers were carried out. The VST multilayers built-up on an aluminum plated glass plate by Langmuir-Blodgett technique were irradiated with electron beams from a Van de Graaff electron accelerator in nitrogen atmosphere. The structure of the multilayers and the effects of irradiation were investigated by X-ray diffractometry, contact angle measurement, multireflection infrared spectroscopy, and scanning electron microscopy. The VST multilayers became insoluble to methanol by the irradiation, and the multi-reflection infrared spectrum of the VST multilayers turned into that of poly (VST) with increasing dosage. The polymerization proceeded during the irradiation at the temperature range between -10 0 and 10 0 C, and the conversion attained to 90% within 2.5 minutes (total dose, 5.6 Mrads). The multilayers irradiated above 13 Mrads turned into the polymer film insoluble to benzene, indicating that the polymer chains were cross-linked by the irradiation. Stearic acid which was formed by the irradiation of VST at nitrogen-water interface as a hydrolysis product was not detected in this system. (auth.)
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International Nuclear Information System (INIS)
Reshak, A. H.; Brik, M. G.; Auluck, S.
2014-01-01
Based on the electronic band structure, we have calculated the dispersion of the linear and nonlinear optical susceptibilities for the mixed CuAl(S 1−x Se x ) 2 chaclcopyrite compounds with x = 0.0, 0.25, 0.5, 0.75, and 1.0. Calculations are performed within the Perdew-Becke-Ernzerhof general gradient approximation. The investigated compounds possess a direct band gap of about 2.2 eV (CuAlS 2 ), 1.9 eV (CuAl(S 0.75 Se 0.25 ) 2 ), 1.7 eV (CuAl(S 0.5 Se 0.5 ) 2 ), 1.5 eV (CuAl(S 0.25 Se 0.75 ) 2 ), and 1.4 eV (CuAlSe 2 ) which tuned to make them optically active for the optoelectronics and photovoltaic applications. These results confirm that substituting S by Se causes significant band gaps' reduction. The optical function's dispersion ε 2 xx (ω) and ε 2 zz (ω)/ε 2 xx (ω), ε 2 yy (ω), and ε 2 zz (ω) was calculated and discussed in detail. To demonstrate the effect of substituting S by Se on the complex second-order nonlinear optical susceptibility tensors, we performed detailed calculations for the complex second-order nonlinear optical susceptibility tensors, which show that the neat parents compounds CuAlS 2 and CuAlSe 2 exhibit | χ 123 (2) (−2ω;ω;ω) | as the dominant component, while the mixed alloys exhibit | χ 111 (2) (−2ω;ω;ω) | as the dominant component. The features of | χ 123 (2) (−2ω;ω;ω) | and | χ 111 (2) (−2ω;ω;ω) | spectra were analyzed on the basis of the absorptive part of the corresponding dielectric function ε 2 (ω) as a function of both ω/2 and ω.
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Corrugated grating on organic multilayer Bragg reflector
Jaquet, Sylvain; Scharf, Toralf; Herzig, Hans Peter
2007-08-01
Polymeric multilayer Bragg structures are combined with diffractive gratings to produce artificial visual color effects. A particular effect is expected due to the angular reflection dependence of the multilayer Bragg structure and the dispersion caused by the grating. The combined effects can also be used to design particular filter functions and various resonant structures. The multilayer Bragg structure is fabricated by spin-coating of two different low-cost polymer materials in solution on a cleaned glass substrate. These polymers have a refractive index difference of about 0.15 and permit multilayer coatings without interlayer problems. Master gratings of different periods are realized by laser beam interference and replicated gratings are superimposed on the multilayer structure by soft embossing in a UV curing glue. The fabrication process requires only polymer materials. The obtained devices are stable and robust. Angular dependent reflection spectrums for the visible are measured. These results show that it is possible to obtain unexpected reflection effects. A rich variety of color spectra can be generated, which is not possible with a single grating. This can be explained by the coupling of transmission of grating orders and the Bragg reflection band. A simple model permits to explain some of the spectral vs angular dependence of reflected light.
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Inkjet-printed Polyvinyl Alcohol Multilayers.
Salaoru, Iulia; Zhou, Zuoxin; Morris, Peter; Gibbons, Gregory J
2017-05-11
Inkjet printing is a modern method for polymer processing, and in this work, we demonstrate that this technology is capable of producing polyvinyl alcohol (PVOH) multilayer structures. A polyvinyl alcohol aqueous solution was formulated. The intrinsic properties of the ink, such as surface tension, viscosity, pH, and time stability, were investigated. The PVOH-based ink was a neutral solution (pH 6.7) with a surface tension of 39.3 mN/m and a viscosity of 7.5 cP. The ink displayed pseudoplastic (non-Newtonian shear thinning) behavior at low shear rates, and overall, it demonstrated good time stability. The wettability of the ink on different substrates was investigated, and glass was identified as the most suitable substrate in this particular case. A proprietary 3D inkjet printer was employed to manufacture polymer multilayer structures. The morphology, surface profile, and thickness uniformity of inkjet-printed multilayers were evaluated via optical microscopy.
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Transmission fingerprints in quasiperiodic magnonic multilayers
Energy Technology Data Exchange (ETDEWEB)
Coelho, I.P. [Departamento de Ensino Superior, Instituto Federal de Educacao, Ciencia e Tecnologia do Maranhao, Imperatriz-MA 65919-050 (Brazil); Departamento de Fisica, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil); Vasconcelos, M.S. [Escola de Ciencias e Tecnologia, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil); Bezerra, C.G., E-mail: cbezerra@dfte.ufrn.br [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, Natal-RN 59072-970 (Brazil)
2011-12-15
In this paper we investigated the influence of mirror symmetry on the transmission spectra of quasiperiodic magnonic multilayers arranged according to Fibonacci, Thue-Morse and double period quasiperiodic sequences. We consider that the multilayers composed of two simple cubic Heisenberg ferromagnets with bulk exchange constants J{sub A} and J{sub B} and spin quantum numbers S{sub A} and S{sub B}, respectively. The multilayer structure is surrounded by two semi-infinite slabs of a third Heisenberg ferromagnetic material with exchange constant J{sub C} and spin quantum number S{sub C}. For simplicity, the lattice constant has the same value a in each material, corresponding to epitaxial growth at the interfaces. The transfer matrix treatment was used for the exchange-dominated regime, taking into account the random phase approximation (RPA). Our numerical results illustrate the effects of mirror symmetry on (i) transmission spectra and (ii) transmission fingerprints. - Highlights: > We model quasiperiodic magnetic multilayers presenting mirror symmetry. > We investigated the allowed and forbidden bands of magnonic transmission. > Transmission return maps show the influence of mirror symmetry. > Mirror symmetry has no effect on the Fibonacci case. > Mirror symmetry does have effect on the Thue-Morse and double period cases.
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Transmission fingerprints in quasiperiodic magnonic multilayers
International Nuclear Information System (INIS)
Coelho, I.P.; Vasconcelos, M.S.; Bezerra, C.G.
2011-01-01
In this paper we investigated the influence of mirror symmetry on the transmission spectra of quasiperiodic magnonic multilayers arranged according to Fibonacci, Thue-Morse and double period quasiperiodic sequences. We consider that the multilayers composed of two simple cubic Heisenberg ferromagnets with bulk exchange constants J A and J B and spin quantum numbers S A and S B , respectively. The multilayer structure is surrounded by two semi-infinite slabs of a third Heisenberg ferromagnetic material with exchange constant J C and spin quantum number S C . For simplicity, the lattice constant has the same value a in each material, corresponding to epitaxial growth at the interfaces. The transfer matrix treatment was used for the exchange-dominated regime, taking into account the random phase approximation (RPA). Our numerical results illustrate the effects of mirror symmetry on (i) transmission spectra and (ii) transmission fingerprints. - Highlights: → We model quasiperiodic magnetic multilayers presenting mirror symmetry. → We investigated the allowed and forbidden bands of magnonic transmission. → Transmission return maps show the influence of mirror symmetry. → Mirror symmetry has no effect on the Fibonacci case. → Mirror symmetry does have effect on the Thue-Morse and double period cases.
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Huang, Qiushi; Louis, Eric; Bijkerk, Frederik; de Boer, Meint J.; von Blanckenhagen, G.
2016-01-01
A multilayer mirror (M) reflecting extreme ultraviolet (EUV) radiation from a first wave-length range in a EUV spectral region comprises a substrate (SUB) and a stack of layers (SL) on the substrate, the stack of layers comprising layers comprising a low index material and a high index material, the
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Energy Technology Data Exchange (ETDEWEB)
Bouaouina, B., E-mail: b.bouaouina@gmail.com [Department of physic, research unite UR-MPE, Boumerdes University 35000 (Algeria); Besnard, A. [Arts et Metiers ParisTech—LaBoMaP, 71250 Cluny (France); Abaidia, S.E. [Department of physic, research unite UR-MPE, Boumerdes University 35000 (Algeria); Haid, F. [CDTA, Plasma discharges Group, Baba hassen, Algers (Algeria)
2017-02-15
Highlights: • Depositing of crystallized molybdenum nitride and chromium nitride multilayer at room temperature. • Correlation between stress measurement and the shift of the XRD diffraction peak (1 1 1) of Mo{sub 2}N. • Studied the effect of the bi-layer thickness on the mechanical properties. - Abstract: We have investigated the effect of the period thickness of the multilayer Mo{sub 2}N/CrN deposited on Si substrate produced by reactive magnetron sputtering. Mo{sub 2}N presents a face centered cubic structure and CrN an orthorhombic one. The residual stress of the coatings was determined by the measurement of the substrate curvature. The microstructure of the multilayer was investigated from the X-ray diffraction and scanning electron microscopy (cross section images). The residual stresses resulting from the deposition of the different bi-layer thickness were measured and correlated to the structural properties of the coating as well as the nanoindentation analysis of the coating. The stresses are compressive and tensile for the individual Mo{sub 2}N and CrN layer respectively. The result shows that an increase of the multilayer coatings Mo{sub 2}N/CrN thicknesses induce an increase of the hardness and the elastic modulus, in the other hand the tensile stress increases. The shift of the XRD diffraction peak (1 1 1) of Mo{sub 2}N at high angle which means the reduction of the residual stress is in good agreement with the residual stresses measurements.
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Kouters, M.H.M.; Gubbels, G.H.M.; O'Halloran, O.; Rongen, R.
2011-01-01
In high power automotive electronics copper wire bonding is regarded as most promising alternative for gold wire bonding in 1 st level interconnects and therefore subjected to severe functional requirements. In the Cu-Al ball bond interface the growth of intermetallic compounds may deteriorate the
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Micro-chip initiator realized by integrating Al/CuO multilayer nanothermite on polymeric membrane
International Nuclear Information System (INIS)
Taton, G; Lagrange, D; Conedera, V; Rossi, C; Renaud, L
2013-01-01
We have developed a new nanothermite based polymeric electro-thermal initiator for non-contact ignition of a propellant. A reactive Al/CuO multilayer nanothermite resides on a 100 µm thick SU-8/PET (polyethyleneterephtalate) membrane to insulate the reactive layer from the silicon bulk substrate. When current is supplied to the initiator, the chemical reaction Al+CuO occurs and sparkles are spread to a distance of several millimeters. A micro-manufacturing process for fabricating the initiator is presented and the electrical behaviors of the ignition elements are also investigated. The characteristics of the initiator made on a 100 µm thick SU-8/PET membrane were compared to two bulk electro-thermal initiators: one on a silicon and one on a Pyrex substrate. The PET devices give 100% of Al/CuO ignition success for an electrical current >250 mA. Glass based reactive initiators give 100% of Al/CuO ignition success for an electrical current >500 mA. Reactive initiators directly on silicon cannot initiate even with a 4 A current. At low currents (<1 A), the initiation time is two orders of magnitude longer for Pyrex initiator compared to those obtained for PET initiator technology. We also observed that, the Al/CuO thermite film on PET membrane reacts within 1 ms (sparkles duration) whereas it reacts within 4 ms on Pyrex. The thermite reaction is 40 times greater in intensity using the PET substrate in comparison to Pyrex. (paper)
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High-frequency characteristics of glass/ceramic composite and alumina multilayer structures
International Nuclear Information System (INIS)
Niwa, K.; Suzuki, H.; Yokoyama, H.; Kamechara, N.; Tsubone, K.; Tanisawa, H.; Sugiki, H.
1990-01-01
This paper reports the transmission characteristics of glass/ceramic composite (borosilicate glass/alumina) and alumina multilayer structures examined. The triplate stripline formed in the glass/ceramic multilayer shows low conductor and dielectric loss. Alumina multilayer, however, has twice the transmission loss at 10 GHz, because the resistivity of W in the alumina multilayer is higher than the Cu in the glass/ceramic multilayer. Crosstalk between striplines in the glass/ceramics is less than -80 dB up to 11 GHz and 9 GHz for alumina
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Multilayer optics for x-ray analysis: design - fabrication - application
International Nuclear Information System (INIS)
Dietsch, R.; Holz, Th.; Bruegemann, L.
2002-01-01
Full text: The use of multilayer optics induced a decisive extension of opportunities in laboratory based X-ray analysis. With the growing number of different applications, more and more dedicated X-ray optics are required, optimized for the spectral range they are intended to be used for. Both the characteristic of the used X-ray source and the design of the multilayer optics finally define the performance of the conditioned incident beam for the application. In any case, qualified spacer and absorber materials have to be selected for the deposition of the multilayer in respect to the designated X-ray wavelength. X-ray optical devices based on uniform multilayers have the advantage of a wide acceptance angle but show chromatic aberrations. This effect can be avoided by synthesizing a multilayer with a lateral thickness gradient. The gradient ensures that any beam of a certain wavelength emitted from an infinite narrow X-ray source impinging the multilayer optics fulfills the Bragg condition. Three different types of curvature of laterally graded multilayer mirrors are used for X-ray analysis experiments: parabolic, elliptic and planar, which result in parallel, focusing and divergent beam conditions, respectively. Furthermore, the X-ray beam characteristics: intensity, monochromasy, divergence, beam width and brilliance can be additionally conditioned by combining one multilayer optics with either a different optic and/or with a crystal monochromator. The deposition of nanometer-multilayers, used as X-ray optical components, result in extraordinary requirements of the deposition process concerning precision, reproducibility and long term stability. Across a stack of more than 150 individual layers with thicknesses in the range between 1 to 10 nm, a variation of single layer thickness considerably lower than σ D = 0.1 nm and an interface roughness below σ R = 0.25 nm have to be achieved. Thickness homogeneity Δd/d -8 have to be guaranteed across macroscopic
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Directory of Open Access Journals (Sweden)
ZHANG Yan
2017-10-01
Full Text Available Based on the molecular dynamics (MD method, transient explosive welding process of Cu/Al junction point was revealed from the microscopic aspect, and mechanical properties and machinability of the Cu/Al nano-weldment were studied. The results show that kinetic energy is converted into internal energy in the system after the collision. The heterogeneous atoms penetrate into each other and the diffusion effect of copper atoms is better than aluminium atoms. The elastic modulus of the nano-weldment is 64.56 GPa, which is between copper's and aluminium's; however, its yield strength is less than those of the two monocrystals. Interactions between dislocations and disordered lattices cause the stress strengthening in the plastic deformation stage, which causes that the stress values of the weldment is larger than those of the two monocrystals. This strengthening mechanism is also reflected in the cutting process, and the weldment has the highest average cutting force 117.80 nN. A mass of dislocations nucleate in the disordered lattice areas of the weldment, and they spread at 45¯ to the cutting direction. However, dislocations pile up when their propagation is hindered by the disordered lattices and interface, which leads to the work hardening effect.
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Bonded Multilayer Laue Lens for focusing hard X-rays
International Nuclear Information System (INIS)
Liu Chian; Conley, R.; Qian, J.; Kewish, C.M.; Macrander, A.T.; Maser, J.; Kang, H.C.; Yan, H.; Stephenson, G.B.
2007-01-01
We have fabricated partial Multilayer Laue Lens (MLL) linear zone plate structures with thousands of alternating WSi 2 and Si layers and various outermost zone widths according to the Fresnel zone plate formula. Using partial MLL structures, we were able to focus hard X-rays to line foci with a width of 30 nm and below. Here, we describe challenges and approaches used to bond these multilayers to achieve line and point focusing. Bonding was done by coating two multilayers with AuSn and heating in a vacuum oven at 280-300 o C. X-ray reflectivity measurements confirmed that there was no change in the multilayers after heating to 350 o C. A bonded MLL was polished to a 5-25 μm wedge without cracking. SEM image analyses found well-positioned multilayers after bonding. These results demonstrate the feasibility of a bonded full MLL for focusing hard X-rays
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Directory of Open Access Journals (Sweden)
Jorge Téllez López
2013-06-01
Full Text Available Durante los meses de enero a mayo de 2013, a través de la metodología propuesta por Alciaturi (2009; se realizó el análisis de los factores socioeconómicos involucrados en la cuenca del rio Cuale, Jalisco, México. Los resultados incluyeron aspectos relacionados con la dinámica demográfica, grado de marginación, nivel educativo, población económicamente activa, principales actividades económicas, comunidades rurales, descripción socioeconómica, potenciales de los recursos naturales, usos y aprovechamientos actuales; así como la situación jurídica de la tenencia de la tierra. El objetivo de esta investigación es conocer cómo estos factores inciden sobre los recursos naturales de la cuenca. Con la finalidad de utilizar esta información para establecer la declaratoria del Área Natural Protegida Reserva de la Biosfera El Cuale, que es una herramienta que puede ayudar a asegurar la conservación de esta zona. Por lo tanto, se han incluido elementos de análisis social, económico y ambiental, puesto que estos factores han resultado determinantes en los procesos que inciden en la deforestación y cambio de uso de suelo.
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Multilayer cladding with hyperbolic dispersion for plasmonic waveguides
DEFF Research Database (Denmark)
Babicheva, Viktoriia; Shalaginov, Mikhail Y.; Ishii, Satoshi
2015-01-01
We study the properties of plasmonic waveguides with a dielectric core and multilayer metal-dielectric claddings that possess hyperbolic dispersion. The waveguides hyperbolic multilayer claddings show better performance in comparison to conventional plasmonic waveguides. © OSA 2015....
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Multilayer scaffolds in orthopaedic tissue engineering.
Atesok, Kivanc; Doral, M Nedim; Karlsson, Jon; Egol, Kenneth A; Jazrawi, Laith M; Coelho, Paulo G; Martinez, Amaury; Matsumoto, Tomoyuki; Owens, Brett D; Ochi, Mitsuo; Hurwitz, Shepard R; Atala, Anthony; Fu, Freddie H; Lu, Helen H; Rodeo, Scott A
2016-07-01
The purpose of this study was to summarize the recent developments in the field of tissue engineering as they relate to multilayer scaffold designs in musculoskeletal regeneration. Clinical and basic research studies that highlight the current knowledge and potential future applications of the multilayer scaffolds in orthopaedic tissue engineering were evaluated and the best evidence collected. Studies were divided into three main categories based on tissue types and interfaces for which multilayer scaffolds were used to regenerate: bone, osteochondral junction and tendon-to-bone interfaces. In vitro and in vivo studies indicate that the use of stratified scaffolds composed of multiple layers with distinct compositions for regeneration of distinct tissue types within the same scaffold and anatomic location is feasible. This emerging tissue engineering approach has potential applications in regeneration of bone defects, osteochondral lesions and tendon-to-bone interfaces with successful basic research findings that encourage clinical applications. Present data supporting the advantages of the use of multilayer scaffolds as an emerging strategy in musculoskeletal tissue engineering are promising, however, still limited. Positive impacts of the use of next generation scaffolds in orthopaedic tissue engineering can be expected in terms of decreasing the invasiveness of current grafting techniques used for reconstruction of bone and osteochondral defects, and tendon-to-bone interfaces in near future.
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Advanced materials for multilayer mirrors for extreme ultraviolet solar astronomy.
Bogachev, S A; Chkhalo, N I; Kuzin, S V; Pariev, D E; Polkovnikov, V N; Salashchenko, N N; Shestov, S V; Zuev, S Y
2016-03-20
We provide an analysis of contemporary multilayer optics for extreme ultraviolet (EUV) solar astronomy in the wavelength ranges: λ=12.9-13.3 nm, λ=17-21 nm, λ=28-33 nm, and λ=58.4 nm. We found new material pairs, which will make new spaceborne experiments possible due to the high reflection efficiencies, spectral resolution, and long-term stabilities of the proposed multilayer coatings. In the spectral range λ=13 nm, Mo/Be multilayer mirrors were shown to demonstrate a better ratio of reflection efficiency and spectral resolution compared with the commonly used Mo/Si. In the spectral range λ=17-21 nm, a new multilayer structure Al/Si was proposed, which had higher spectral resolution along with comparable reflection efficiency compared with the commonly used Al/Zr multilayer structures. In the spectral range λ=30 nm, the Si/B4C/Mg/Cr multilayer structure turned out to best obey reflection efficiency and long-term stability. The B4C and Cr layers prevented mutual diffusion of the Si and Mg layers. For the spectral range λ=58 nm, a new multilayer Mo/Mg-based structure was developed; its reflection efficiency and long-term stability have been analyzed. We also investigated intrinsic stresses inherent for most of the multilayer structures and proposed possibilities for stress elimination.
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Identifying key nodes in multilayer networks based on tensor decomposition.
Wang, Dingjie; Wang, Haitao; Zou, Xiufen
2017-06-01
The identification of essential agents in multilayer networks characterized by different types of interactions is a crucial and challenging topic, one that is essential for understanding the topological structure and dynamic processes of multilayer networks. In this paper, we use the fourth-order tensor to represent multilayer networks and propose a novel method to identify essential nodes based on CANDECOMP/PARAFAC (CP) tensor decomposition, referred to as the EDCPTD centrality. This method is based on the perspective of multilayer networked structures, which integrate the information of edges among nodes and links between different layers to quantify the importance of nodes in multilayer networks. Three real-world multilayer biological networks are used to evaluate the performance of the EDCPTD centrality. The bar chart and ROC curves of these multilayer networks indicate that the proposed approach is a good alternative index to identify real important nodes. Meanwhile, by comparing the behavior of both the proposed method and the aggregated single-layer methods, we demonstrate that neglecting the multiple relationships between nodes may lead to incorrect identification of the most versatile nodes. Furthermore, the Gene Ontology functional annotation demonstrates that the identified top nodes based on the proposed approach play a significant role in many vital biological processes. Finally, we have implemented many centrality methods of multilayer networks (including our method and the published methods) and created a visual software based on the MATLAB GUI, called ENMNFinder, which can be used by other researchers.
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Magnetic studies in evaporated Ni/Pd multilayers
International Nuclear Information System (INIS)
Chafai, K.; Salhi, H.; Lassri, H.; Yamkane, Z.; Lassri, M.; Abid, M.; Hlil, E.K.; Krishnan, R.
2011-01-01
The magnetic properties of Ni/Pd multilayers, prepared by sequential evaporation in ultrahigh vacuum, have been studied. The Ni thickness dependence of the magnetization and magnetic anisotropy is discussed. The temperature dependence of the spontaneous magnetization is well described by a T 3/2 law in all multilayers. A spin-wave theory has been used to explain the temperature dependence of the spontaneous magnetization, and the approximate values for the exchange interactions for various Ni layer thicknesses have been obtained. - Research highlights: → The magnetic properties of Ni/Pd multilayers, prepared by sequential evaporation in ultrahigh vacuum, have been studied. → The temperature dependence of the spontaneous magnetization is well described by a T 3/2 law in Ni/Pd multilayers. → The spin-wave constant B was observed to depend on t Ni nonmonotonically. → A spin-wave theory has been used to explain the temperature dependence of the spontaneous magnetization. → The approximate values for the exchange interactions for various Ni layer thicknesses have been obtained.
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Wang, Yuhui; Liao, Bo; Liu, Jianhua; Chen, Shuqing; Feng, Yu; Zhang, Yanyan; Zhang, Ruijun
2012-07-01
The solid-state phase transformation temperature and duration of deep cryogenic treated and untreated Cu-Al alloys in cooling process were measured by differential scanning calorimetry measurement. The solid-state phase transformation activation energy and Avrami exponent were calculated according to these measurements. The effects of deep cryogenic treatment on the solid-state phase transformation were investigated based on the measurement and calculation as well as the observation of alloy's microstructure. The results show that deep cryogenic treatment can increase the solid-phase transformation activation energy and shorten the phase transformation duration, which is helpful to the formation of fine grains in Cu-Al alloy.
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Reactive diffusion in Sc/Si multilayer X-ray mirrors with CrB2 barrier layers
International Nuclear Information System (INIS)
Pershyn, Y.P.; Zubarev, E.N.; Kondratenko, V.V.; Sevryukova, V.A.; Kurbatova, S.V.
2011-01-01
Processes undergoing in Sc/Si multilayer X-ray mirrors (MXMs) with periods of ∝27 nm and barrier layers of CrB 2 0.3- and 0.7-nm thick within the temperature range of 420-780 K were studied by methods of small-angle X-ray reflectivity (λ=0.154 nm) and cross-sectional transmission electron microscopy. All layers with the exception of Sc ones are amorphous. Barrier layers are stable at least up to a temperature of 625 K and double the activation energy of diffusional intermixing at moderate temperatures. Introduction of barriers improves the thermal stability of Sc/Si MXMs at least by 80 degrees. Diffusion of Si atoms through barrier layers into Sc layers with formation of silicides was shown to be the main degradation mechanism of MXMs. A comparison of the stability for Sc/Si MXMs with different barriers published in the literature is conducted. The ways of further improvement of barrier properties are discussed. (orig.)
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Fabrication and performance characterization of Al/Ni multilayer energetic films
Yang, Cheng; Hu, Yan; Shen, Ruiqi; Ye, Yinghua; Wang, Shouxu; Hua, Tianli
2014-02-01
Al/Ni multilayer bridge films, which were composed of alternate Al and Ni layers with bilayer thicknesses of 50, 100 and 200 nm, were prepared by RF magnetron sputtering. In each bilayer, the thickness ratio of Al to Ni was maintained at 3:2 to obtain an overall 1:1 atomic composition. The total thickness of Al/Ni multilayer films was 2 μm. XRD measurements show that the compound of AlNi is the final product of the exothermic reactions. DSC curves show that the values of heat release in Al/Ni multilayer films with bilayer thicknesses of 50, 100 and 200 nm are 389.43, 396.69 and 409.92 J g-1, respectively. The temperatures of Al/Ni multilayer films were obviously higher than those of Al bridge film and Ni bridge film. Al/Ni multilayer films with modulation of 50 nm had the highest electrical explosion temperature of 7000 K. The exothermic reaction in Al/Ni multilayer films leads to a more intense electric explosion. Al/Ni multilayer bridge films with modulation period of 50 nm explode more rapidly and intensely than other bridge films because decreasing the bilayer thickness results in an increased reaction velocity.
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Oromucosal multilayer films for tailor-made, controlled drug delivery.
Lindert, Sandra; Breitkreutz, Jörg
2017-11-01
The oral mucosa has recently become increasingly important as an alternative administration route for tailor-made, controlled drug delivery. Oromucosal multilayer films, assigned to the monograph oromucosal preparations in the Ph.Eur. may be a promising dosage form to overcome the requirements related to this drug delivery site. Areas covered: We provide an overview of multilayer films as drug delivery tools, and discuss manufacturing processes and characterization methods. We focus on the suitability of characterization methods for particular requirements of multilayer films. A classification was performed covering indication areas and APIs incorporated in multilayer film systems for oromucosal use in order to provide a summary of data published in this field. Expert opinion: The shift in drug development to high molecular weight drugs will influence the field of pharmaceutical development and delivery technologies. For a high number of indication areas, such as hormonal disorders, cardiovascular diseases or local treatment of infections, the flexible layer design of oromucosal multilayer films provides a promising option for tailor-made, controlled delivery of APIs to or through defined surfaces in the oral cavity. However, there is a lack of discriminating or standardized testing methods to assess the quality of multilayer films in a reliable way.
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Cell surface engineering with polyelectrolyte multilayer thin films.
Wilson, John T; Cui, Wanxing; Kozlovskaya, Veronika; Kharlampieva, Eugenia; Pan, Di; Qu, Zheng; Krishnamurthy, Venkata R; Mets, Joseph; Kumar, Vivek; Wen, Jing; Song, Yuhua; Tsukruk, Vladimir V; Chaikof, Elliot L
2011-05-11
Layer-by-layer assembly of polyelectrolyte multilayer (PEM) films represents a bottom-up approach for re-engineering the molecular landscape of cell surfaces with spatially continuous and molecularly uniform ultrathin films. However, fabricating PEMs on viable cells has proven challenging owing to the high cytotoxicity of polycations. Here, we report the rational engineering of a new class of PEMs with modular biological functionality and tunable physicochemical properties which have been engineered to abrogate cytotoxicity. Specifically, we have discovered a subset of cationic copolymers that undergoes a conformational change, which mitigates membrane disruption and facilitates the deposition of PEMs on cell surfaces that are tailorable in composition, reactivity, thickness, and mechanical properties. Furthermore, we demonstrate the first successful in vivo application of PEM-engineered cells, which maintained viability and function upon transplantation and were used as carriers for in vivo delivery of PEMs containing biomolecular payloads. This new class of polymeric film and the design strategies developed herein establish an enabling technology for cell transplantation and other therapies based on engineered cells. © 2011 American Chemical Society
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Design of a normal incidence multilayer imaging X-ray microscope
Shealy, David L.; Gabardi, David R.; Hoover, Richard B.; Walker, Arthur B. C., Jr.; Lindblom, Joakim F.
Normal incidence multilayer Cassegrain X-ray telescopes were flown on the Stanford/MSFC Rocket X-ray Spectroheliograph. These instruments produced high spatial resolution images of the sun and conclusively demonstrated that doubly reflecting multilayer X-ray optical systems are feasible. The images indicated that aplanatic imaging soft X-ray/EUV microscopes should be achievable using multilayer optics technology. A doubly reflecting normal incidence multilayer imaging X-ray microscope based on the Schwarzschild configuration has been designed. The design of the microscope and the results of the optical system ray trace analysis are discussed. High resolution aplanatic imaging X-ray microscopes using normal incidence multilayer X-ray mirrors should have many important applications in advanced X-ray astronomical instrumentation, X-ray lithography, biological, biomedical, metallurgical, and laser fusion research.
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78 FR 30329 - Multilayered Wood Flooring from China
2013-05-22
...)] Multilayered Wood Flooring from China AGENCY: United States International Trade Commission. ACTION: Notice of...-1179 (Final) concerning multilayered wood flooring (``MLWF'') from China. For further information... reconsider ``its decision not to investigate domestic producers of hardwood plywood used for flooring'' 2. to...
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POLYELECTROLYTE MULTILAYER STAMPING IN AQUEOUS PHASE AND NON-CONTACT MODE
Mehrotra, Sumit; Lee, Ilsoon; Liu, Chun; Chan, Christina
2011-01-01
Polyelectrolyte multilayer (PEM) transfer printing has been previously achieved by stamping under dry conditions. Here, we show for the first time, that PEM can be transferred from a stamp to the base substrate under aqueous conditions whereby the two surfaces are in a non-contact mode. Degradable multilayers of (PAA/PEG)10.5 followed by non-degradable multilayers of (PDAC/SPS)80.5 were fabricated under acidic pH conditions on either PDMS or glass (stamp), and subsequently transferred over top of another multilayer prepared on a different substrate (base substrate), with a spacing of ~ 200 μm between the stamping surface and the base substrate. This multilayer transfer was performed under physiological pH conditions. This process is referred to herein as non-contact, aqueous-phase multilayer (NAM) transfer. NAM transfer can be useful for applications such as fabricating three-dimensional (3-D) cellular scaffolds. We attempted to create a 3-D cellular scaffold using NAM transfer, and characterized the scaffolds with conventional and fluorescence microscopy. PMID:21860540
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Zone compensated multilayer laue lens and apparatus and method of fabricating the same
Conley, Raymond P.; Liu, Chian Qian; Macrander, Albert T.; Yan, Hanfei; Maser, Jorg; Kang, Hyon Chol; Stephenson, Gregory Brian
2015-07-14
A multilayer Laue Lens includes a compensation layer formed in between a first multilayer section and a second multilayer section. Each of the first and second multilayer sections includes a plurality of alternating layers made of a pair of different materials. Also, the thickness of layers of the first multilayer section is monotonically increased so that a layer adjacent the substrate has a minimum thickness, and the thickness of layers of the second multilayer section is monotonically decreased so that a layer adjacent the compensation layer has a maximum thickness. In particular, the compensation layer of the multilayer Laue lens has an in-plane thickness gradient laterally offset by 90.degree. as compared to other layers in the first and second multilayer sections, thereby eliminating the strict requirement of the placement error.
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Electron irradiation effect on short-range ordering in Cu-Al and Ag-Al alloys
International Nuclear Information System (INIS)
Kulish, N.P.; Mel'nikova, N.A.; Petrenko, P.V.; Ryabishchuk, A.L.; Tatarov, A.A.
1990-01-01
Method of X-ray diffuse scattering is used to study short-range order variation in Cu-Al and Ag-Al alloys under radiation effect and the following heat treatment. Irradiation was carried out at -40 deg C by 1.6 MeV electrons, fluence of 5x10 7 cm -2 and 0.5 MeV gamma-rays, the dose being 10 7 pH
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Effect of Ternary Addition of Iron on Shape Memory Characteristics of Cu-Al Alloys
Raju, T. N.; Sampath, V.
2011-07-01
The effect of alloying Cu-Al alloys with Fe on their transformation temperatures and shape memory properties was investigated by differential scanning calorimetry and bend test. It was found that the minor additions of iron resulted in change of transformation temperatures and led to excellent shape memory properties of the alloys. Since the transformation temperatures are high, they are an ideal choice for high-temperature applications.
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Multilayer Integrated Film Bulk Acoustic Resonators
Zhang, Yafei
2013-01-01
Multilayer Integrated Film Bulk Acoustic Resonators mainly introduces the theory, design, fabrication technology and application of a recently developed new type of device, multilayer integrated film bulk acoustic resonators, at the micro and nano scale involving microelectronic devices, integrated circuits, optical devices, sensors and actuators, acoustic resonators, micro-nano manufacturing, multilayer integration, device theory and design principles, etc. These devices can work at very high frequencies by using the newly developed theory, design, and fabrication technology of nano and micro devices. Readers in fields of IC, electronic devices, sensors, materials, and films etc. will benefit from this book by learning the detailed fundamentals and potential applications of these advanced devices. Prof. Yafei Zhang is the director of the Ministry of Education’s Key Laboratory for Thin Films and Microfabrication Technology, PRC; Dr. Da Chen was a PhD student in Prof. Yafei Zhang’s research group.
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Enhancement of oxidation resistance in Cu and Cu(Al) thin layers
International Nuclear Information System (INIS)
Horvath, Z.E.; Peto, G.; Paszti, Z.; Zsoldos, E.; Szilagyi, E.; Battistig, G.; Lohner, T.; Molnar, G.L.; Gyulai, J.
1999-01-01
High conductivity and good resistance to electromigration makes copper a promising interconnect material in microelectronics. However, one of its disadvantages is the poor corrosion resistance. Two methods of passivation are investigated and compared: Al alloying and BF 2 + ion implantation. X-ray diffraction (XRD) and Rutherford Backscattering Spectrometry (RBS) show the oxidation inhibition of both methods, but the different ratio of CuO 2 to CuO phases suggests different mechanisms of passivation. There are no definite oxide lines in the XRD spectrum of the implanted and annealed Cu(Al) sample, so the presence of Al and the implantation together give increased protection against oxidation. The difference between the two mechanisms of oxidation inhibition is discussed briefly
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Energy Technology Data Exchange (ETDEWEB)
Trishkina, L., E-mail: trishkina.53@mail.ru; Zboykova, N.; Koneva, N., E-mail: koneva@tsuab.ru; Kozlov, E. [Tomsk State University of Architecture and Building, 2 Solyanaya St., Tomsk, 634003 (Russian Federation); Cherkasova, T. [Tomsk State University of Architecture and Building, 2 Solyanaya St., Tomsk, 634003 (Russian Federation); National Research Tomsk Polytechnic University, 50 Lenin Ave., Tomsk, 634050 (Russian Federation)
2016-01-15
The aim of the investigation was the determination of the statistic description of dislocation distribution in each dislocation substructures component forming after different deformation degrees in the Cu-Al alloys. The dislocation structures were investigated by the transmission diffraction electron microscopy method. In the work the statistic description of distance distribution between the dislocations, dislocation barriers and dislocation tangles in the deformed Cu-Al alloys with different concentration of Al and test temperature at the grain size of 100 µm was carried out. It was established that the above parameters influence the dislocation distribution in different types of the dislocation substructures (DSS): dislocation chaos, dislocation networks without disorientation, nondisoriented and disoriented cells, in the walls and inside the cells. The distributions of the distances between dislocations in the investigated alloys for each DSS type formed at certain deformation degrees and various test temperatures were plotted.
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Trishkina, L.; Cherkasova, T.; Zboykova, N.; Koneva, N.; Kozlov, E.
2016-01-01
The aim of the investigation was the determination of the statistic description of dislocation distribution in each dislocation substructures component forming after different deformation degrees in the Cu-Al alloys. The dislocation structures were investigated by the transmission diffraction electron microscopy method. In the work the statistic description of distance distribution between the dislocations, dislocation barriers and dislocation tangles in the deformed Cu-Al alloys with different concentration of Al and test temperature at the grain size of 100 µm was carried out. It was established that the above parameters influence the dislocation distribution in different types of the dislocation substructures (DSS): dislocation chaos, dislocation networks without disorientation, nondisoriented and disoriented cells, in the walls and inside the cells. The distributions of the distances between dislocations in the investigated alloys for each DSS type formed at certain deformation degrees and various test temperatures were plotted.
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Tunable drug loading and release from polypeptide multilayer nanofilms
Jiang, Bingbing; Li, Bingyun
2009-01-01
Polypeptide multilayer nanofilms were prepared using electrostatic layer-by-layer self-assembly nanotechnology. Small charged drug molecules (eg, cefazolin, gentamicin, and methylene blue) were loaded in polypeptide multilayer nanofilms. Their loading and release were found to be pH-dependent and could also be controlled by changing the number of film layers and drug incubation time, and applying heat-treatment after film formation. Antibioticloaded polypeptide multilayer nanofilms showed controllable antibacterial properties against Staphylococcus aureus. The developed biodegradable polypeptide multilayer nanofilms are capable of loading both positively- and negatively-charged drug molecules and promise to serve as drug delivery systems on biomedical devices for preventing biomedical device-associated infection, which is a significant clinical complication for both civilian and military patients. PMID:19421369
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Strength and thermal stability of Cu-Al2O3 composite obtained by internal oxidation
Directory of Open Access Journals (Sweden)
Jovanovic, M. T.
2010-12-01
Full Text Available The objective of the work is to study the effects of the high-energy milling on strengthening, thermal stability and electrical conductivity of Cu-Al2O3 composite. The prealloyed copper powders, atomized in inert gas and containing 3 wt. % Al, were milled up to 20 h in the planetary ball mill to oxidize in situ aluminium with oxygen from the air. Composite compacts were obtained by hot-pressing in an argon atmosphere at 800 °C for 3 h under the pressure of 35MPa. The microstructural characterization was performed by the optical microscope, scanning electron microscope (SEM, transmission electron microscope (TEM and X-ray diffraction analysis (XRD. The microhardness, electrical conductivity and density measurements were also carried out. The effect of internal oxidation and high-energy milling on strengthening of Cu-Al2O3 composite was significant, The increase of the microhardness of composite compacts (292 HV is almost threefold comparing to compacts processed from the as-received Cu-3 wt. % Al powder (102 HV. The grain size of Cu-Al2O3 compacts processed from 5 and 20 h-milled powders was 75 and 45 nm, respectively. The small increase in the grain size and the small microhardness drop indicate the high thermal stability of Cu-Al2O3 composite during high-temperature exposure at 800 °C.El objetivo del trabajo es el estudio de los efectos de la pulverización con altas energías sobre la resistencia, estabilidad térmica y conductividad eléctrica del compuesto Cu-Al2O3. El polvo pre-aleado de cobre, obtenido a través de la atomización con gas inerte y con un contenido de 3wt. % Al, se molió durante 20 h en el molino planetario de bolas dando lugar a la oxidación in situ del aluminio con el oxígeno del aire. El compuesto compactado se ha obtenido mediante prensado en caliente en atmósfera de argón a 800 °C durante 3 h y a una presión de 35MPa. La caracterización microestructural se hizo a través de microscopia óptica, microscopia
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Magnons in ultrahigh vacuum deposited Fe/Ag multilayers
International Nuclear Information System (INIS)
El Kiadi, I.; Lassri, H.; Benkirane, K.; Bensassi, B.
2007-01-01
We have grown Fe/Ag multilayers with Ag buffer layer, by evaporation under UHV conditions on glass substrates. The magnetic properties of Fe/Ag multilayers are examined as a function of Fe layer thickness t Fe . The temperature dependence of the spontaneous magnetization M(T) is well described by a T 3/2 law in all multilayers. A spin-wave theory has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction J b and surface exchange interaction J s for various Fe layer thicknesses have been obtained
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Covalently attached multilayer assemblies of diazo-resins and binuclear cobalt phthalocyanines
International Nuclear Information System (INIS)
Li Xiaofang; Zhao Shuang; Yang Min; Sun Changqing; Guo, Liping
2005-01-01
By using the ionic self-assembly technique, ordered multilayer thin films composed of diazo-resin (DAR) as polycation and water-soluble binuclear cobalt phthalocyaninehexasulfonate (Bi-CoPc) as polyanion were alternately fabricated on quartz, CaF 2 and glassy carbon electrodes (GCEs). Upon ultraviolet irradiation, the adjacent interface of the multilayer films reacted to form a covalently cross-linking structure. The obtained thin films were characterized by ultraviolet (UV)-vis, Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), atomic force microscope (AFM), surface photovoltage spectra (SPS), and cyclic voltammetry. The results show that the uniform, highly stable and ordered multilayer thin films were formed. The linkage nature between the adjacent interface of the multilayer films converts from ionic to covalent, and, as a result, the stability of the multilayer thin films dramatically improved. The multilayer thin films on GCEs also exhibited excellent electrochemical behavior
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Covalently attached multilayer assemblies of diazo-resins and binuclear cobalt phthalocyanines
Energy Technology Data Exchange (ETDEWEB)
Li Xiaofang [Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130023 (China); Zhao Shuang [Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130023 (China); Yang Min [Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130023 (China); Sun Changqing [Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130023 (China)]. E-mail: sunchq@mail.jlu.edu.cn; Guo, Liping [Department of Chemistry, Northeast Normal University, Changchun 130024 (China)
2005-05-01
By using the ionic self-assembly technique, ordered multilayer thin films composed of diazo-resin (DAR) as polycation and water-soluble binuclear cobalt phthalocyaninehexasulfonate (Bi-CoPc) as polyanion were alternately fabricated on quartz, CaF{sub 2} and glassy carbon electrodes (GCEs). Upon ultraviolet irradiation, the adjacent interface of the multilayer films reacted to form a covalently cross-linking structure. The obtained thin films were characterized by ultraviolet (UV)-vis, Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), atomic force microscope (AFM), surface photovoltage spectra (SPS), and cyclic voltammetry. The results show that the uniform, highly stable and ordered multilayer thin films were formed. The linkage nature between the adjacent interface of the multilayer films converts from ionic to covalent, and, as a result, the stability of the multilayer thin films dramatically improved. The multilayer thin films on GCEs also exhibited excellent electrochemical behavior.
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Gubbels, G.H.M.; Kouters, M.H.M.; Dos Santos Ferreira, O.
2012-01-01
In high power automotive electronics copper wire bonding is regarded as the most promising alternative for gold wire bonding in 1st level interconnects. In the Cu-Al ball bond interface the growth of intermetallic compounds can deteriorate the electrical and mechanical properties of the
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Composition of Cu/Al system constructed by means of dynamic atomic deposition
International Nuclear Information System (INIS)
Tashlykov, I.S.; Tul'ev, V.V.
2011-01-01
Rutherford backscattering and RUMP simulation programme have been applied to investigate composition of Cu/Al system prepared using dynamic atomic deposition process when deposition of Cu thin film on Al substrate was assisted with 6 keV Ar + ions irradiation. It is estimated that thin ( ~15 nm) surface layer consists of ~50 at.% Cu, ~10 at.% Ar, ~4 at.% O and the remaining is Al. Dynamic deposition of Cu on Al substrate is accompanied with radiation enhanced diffusion of Cu, O, Ar atoms in substrate and out diffusion of Al atoms in deposited Cu coating. (authors)
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Multilayer thin films: sequential assembly of nanocomposite materials
National Research Council Canada - National Science Library
Decher, Gero; Schlenoff, Joseph B
2003-01-01
... polymeric or nanoparticulate building blocks, understanding the polymer physical chemistry of multilayers, or characterizing their optical, electrical or biological activities. The reasons for the intense interest in the field are also clearly evident: multilayers bridge the gap between monolayers and spun-on or dip-coated films, ...
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Design and performance of capping layers for extreme-ultraviolet multilayer mirrors
International Nuclear Information System (INIS)
Bajt, Sasa; Chapman, Henry N.; Nguyen, Nhan; Alameda, Jennifer; Robinson, Jeffrey C.; Malinowski, Michael; Gullikson, Eric; Aquila, Andrew; Tarrio, Charles; Grantham, Steven
2003-01-01
Multilayer lifetime has emerged as one of the major issues for the commercialization of extreme-ultraviolet lithography (EUVL). We describe the performance of an oxidation-resistant capping layer of Ru atop multilayers that results in a reflectivity above 69% at 13.2 nm, which is suitable for EUVL projection optics and has been tested with accelerated electron-beam and extreme-ultraviolet (EUV) light in a water-vapor environment. Based on accelerated exposure results, we calculated multilayer lifetimes for all reflective mirrors in a typical commercial EUVL tool and concluded that Ru-capped multilayers have ∼40x longer lifetimes than Si-capped multilayers, which translates to 3 months to many years, depending on the mirror dose
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Magnetic damping phenomena in ferromagnetic thin-films and multilayers
Azzawi, S.; Hindmarch, A. T.; Atkinson, D.
2017-11-01
Damped ferromagnetic precession is an important mechanism underpinning the magnetisation processes in ferromagnetic materials. In thin-film ferromagnets and ferromagnetic/non-magnetic multilayers, the role of precession and damping can be critical for spintronic device functionality and as a consequence there has been significant research activity. This paper presents a review of damping in ferromagnetic thin-films and multilayers and collates the results of many experimental studies to present a coherent synthesis of the field. The terms that are used to define damping are discussed with the aim of providing consistent definitions for damping phenomena. A description of the theoretical basis of damping is presented from early developments to the latest discussions of damping in ferromagnetic thin-films and multilayers. An overview of the time and frequency domain methods used to study precessional magnetisation behaviour and damping in thin-films and multilayers is also presented. Finally, a review of the experimental observations of magnetic damping in ferromagnetic thin-films and multilayers is presented with the most recent explanations. This brings together the results from many studies and includes the effects of ferromagnetic film thickness, the effects of composition on damping in thin-film ferromagnetic alloys, the influence of non-magnetic dopants in ferromagnetic films and the effects of combining thin-film ferromagnets with various non-magnetic layers in multilayered configurations.
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Thermal-Insulation Properties of Multilayer Textile Packages
Directory of Open Access Journals (Sweden)
Matusiak Małgorzata
2014-12-01
Full Text Available Thermal-insulation properties of textile materials play a significant role in material engineering of protective clothing. Thermal-insulation properties are very important from the point of view of thermal comfort of the clothing user as well as the protective efficiency against low or high temperature. Thermal protective clothing usually is a multilayer construction. Its thermal insulation is a resultant of a number of layers and their order, as well as the thermalinsulation properties of a single textile material creating particular layers. The aim of the presented work was to investigate the relationships between the thermal-insulation properties of single materials and multilayer textile packages composed of these materials. Measurement of the thermal-insulation properties of single and multilayer textile materials has been performed with the Alambeta. The following properties have been investigated: thermal conductivity, resistance and absorptivity. Investigated textile packages were composed of two, three and four layers made of woven and knitted fabrics, as well as nonwovens. On the basis of the obtained results an analysis has been carried out in order to assess the dependency of the resultant values of the thermal-insulation properties of multilayer packages on the appropriate values of particular components.
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Communication: Reactivity borrowing in the mode selective chemistry of H + CHD3 → H2 + CD3
Ellerbrock, Roman; Manthe, Uwe
2017-12-01
Quantum state-resolved reaction probabilities for the H + CHD3 → H2 + CD3 reaction are calculated by accurate full-dimensional quantum dynamics calculations using the multi-layer multi-configurational time-dependent Hartree approach and the quantum transition state concept. Reaction probabilities of various ro-vibrational states of the CHD3 reactant are investigated for vanishing total angular momentum. While the reactivity of the different vibrational states of CHD3 mostly follows intuitive patterns, an unusually large reaction probability is found for CHD3 molecules triply excited in the CD3 umbrella-bending vibration. This surprising reactivity can be explained by a Fermi resonance-type mixing of the single CH-stretch excited and the triple CD3 umbrella-bend excited vibrational states of CHD3. These findings show that resonant energy transfer can significantly affect the mode-selective chemistry of CHD3 and result in counter-intuitive reactivity patterns.
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Clustering multilayer omics data using MuNCut.
Teran Hidalgo, Sebastian J; Ma, Shuangge
2018-03-14
Omics profiling is now a routine component of biomedical studies. In the analysis of omics data, clustering is an essential step and serves multiple purposes including for example revealing the unknown functionalities of omics units, assisting dimension reduction in outcome model building, and others. In the most recent omics studies, a prominent trend is to conduct multilayer profiling, which collects multiple types of genetic, genomic, epigenetic and other measurements on the same subjects. In the literature, clustering methods tailored to multilayer omics data are still limited. Directly applying the existing clustering methods to multilayer omics data and clustering each layer first and then combing across layers are both "suboptimal" in that they do not accommodate the interconnections within layers and across layers in an informative way. In this study, we develop the MuNCut (Multilayer NCut) clustering approach. It is tailored to multilayer omics data and sufficiently accounts for both across- and within-layer connections. It is based on the novel NCut technique and also takes advantages of regularized sparse estimation. It has an intuitive formulation and is computationally very feasible. To facilitate implementation, we develop the function muncut in the R package NcutYX. Under a wide spectrum of simulation settings, it outperforms competitors. The analysis of TCGA (The Cancer Genome Atlas) data on breast cancer and cervical cancer shows that MuNCut generates biologically meaningful results which differ from those using the alternatives. We propose a more effective clustering analysis of multiple omics data. It provides a new venue for jointly analyzing genetic, genomic, epigenetic and other measurements.
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75 FR 66126 - Multilayered Wood Flooring From China
2010-10-27
...)] Multilayered Wood Flooring From China AGENCY: United States International Trade Commission. ACTION: Institution... flooring, provided for in subheadings 4409.10, 4409.29, 4412.31, 4412.32, 4412.39, 4412.94, 4412.99, 4418... multilayered wood flooring. The following companies are members of the CAHP: Anderson Hardwood Floors, LLC...
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Simulation of reflectivity spectrum for non-absorbing multilayer ...
Indian Academy of Sciences (India)
Reflectivity simulation is an essential tool for the design and optimization of optical thin ... with the experimental results of the multilayer optical thin films grown by electron-beam evaporation ... beam splitters [4] and various optical filters. ... thickness (QWOT) layer AR coating and multilayer HR coating using electron- beam ...
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Reference Models for Multi-Layer Tissue Structures
2016-09-01
function of multi-layer tissues (etiology and management of pressure ulcers ). What was the impact on other disciplines? As part of the project, a data...simplification to develop cost -effective models of surface manipulation of multi-layer tissues. Deliverables. Specimen- (or subject) and region-specific...simplification to develop cost -effective models of surgical manipulation. Deliverables. Specimen-specific surrogate models of upper legs confirmed against data
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Interface-engineered spin-dependent transport in perpendicular Co/Pt multilayers
Energy Technology Data Exchange (ETDEWEB)
Jiang, Shao-Long; Yang, Guang; Teng, Jiao, E-mail: tengjiao@mater.ustb.edu.cn; Guo, Qi-Xun; Li, Lei-Lei; Yu, Guang-Hua, E-mail: ghyu@mater.ustb.edu.cn
2016-11-30
Highlights: • The anomalous Hall effect in Co/Pt multilayers is studied. • Thermally stable AHE feature is obtained in [Pt/Co]{sub 3}/Ta/MgO multilayers. • Good thermal stability is due to enhanced side-jump and intrinsic contributions. - Abstract: The improvement of anomalous Hall effect (AHE) has been obtained through the introduction of a Ta metallic layer at the Co/MgO interface in perpendicular [Pt/Co]{sub 3}/MgO multilayers. It is exhibited that the saturation anomalous Hall resistivity is 42% larger than that in Co/Pt multilayers without Ta insertion. More meaningfully, thermally stable AHE feature is gained in perpendicular [Pt/Co]{sub 3}/Ta/MgO multilayers despite Co-Pt interdiffusion. The AHE is enhanced for sample [Pt/Co]{sub 3}/Ta/MgO after annealing, mainly due to the enhancement of the side-jump and intrinsic contributions.
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Structural integrity of ceramic multilayer capacitor materials and ceramic multilayer capacitors
With, de G.
1993-01-01
An review with 61 refs. is given of the fracture of and stress situation in ceramic capacitor materials and ceramic multilayer capacitors. A brief introduction to the relevant concepts is given first. Next the data for capacitor materials and the data for capacitors are discussed. The materials data
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Optical measurement of thermal deformation of multilayer optics under synchrotron radiation
International Nuclear Information System (INIS)
Revesz, P.; Kazimirov, A.; Bazarov, I.
2007-01-01
An in situ optical technique to visualize surface distortions of the first monochromator crystal under synchrotron beam heat loading has been developed and applied to measure surface profiles of multilayer optics under white wiggler beam at the CHESS A2 beamline. Two identical multilayer structures deposited on Si and SiC substrates have been tested. Comparison of the reconstructed 3D heatbump profiles showed the surface distortions of the multilayer on SiC a factor of two smaller than the same multilayer on a Si substrate
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Optical measurement of thermal deformation of multilayer optics under synchrotron radiation
Energy Technology Data Exchange (ETDEWEB)
Revesz, P. [Cornell University, CHESS, Ithaca, NY 14850 (United States)], E-mail: pr20@cornell.edu; Kazimirov, A.; Bazarov, I. [Cornell University, CHESS, Ithaca, NY 14850 (United States)
2007-11-11
An in situ optical technique to visualize surface distortions of the first monochromator crystal under synchrotron beam heat loading has been developed and applied to measure surface profiles of multilayer optics under white wiggler beam at the CHESS A2 beamline. Two identical multilayer structures deposited on Si and SiC substrates have been tested. Comparison of the reconstructed 3D heatbump profiles showed the surface distortions of the multilayer on SiC a factor of two smaller than the same multilayer on a Si substrate.
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International Nuclear Information System (INIS)
Chen, Tianchi; Ge, Shirong; Liu, Hongtao; Sun, Qinghe; Zhu, Wei; Yan, Wei; Qi, Jianwei
2015-01-01
Highlights: • We fabricate a low adhesive superhydrophobic nano Cu/Al 2 O 3 composited Ni–Cr coating via brush plating. • We investigate the influence of process parameters on hydrophobic properties process. • We discuss the formation mechanism of structures on the surface and using water rebound height to explain the low adhesive force mechanism. - Abstract: Superhydrophobic nano Cu/Al 2 O 3 Ni–Cr composited coating with a low adhesive force was deposited onto the Q345 carbon steel via electro-brush plating. Surface morphologies of nano Cu/Al 2 O 3 Ni–Cr composited coating were investigated by scanning electron microscope (SEM). Chemical compositions were characterized by energy dispersive spectroscopy (EDS). First of all, by adjusting different process parameters such as working voltage, relative velocity, Cu particles concentration and plating time, we obtain the most optimal parameters: working voltage is 15 V, relative velocity is 4.8 m/min, Cu particles concentration is 5 g/L and plating time is 60 s. Under the best process parameters, the water contact angle reaches to 156° and a sliding angle is less than 2° on the nano Cu/Al 2 O 3 Ni–Cr coating. Then the mechanism of the superhydrophobic and low adhesion characteristic of this surface were explained by Cassie's model. Low adhesive force can be characterized by max rebound height of water droplet. As a result, to achieve low adhesive surface it is necessary to decrease the fraction of the solid/liquid interface under the water droplet. Finally the coating was proved to have an excellent self-cleaning performance.
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Phosphorus-based compounds for EUV multilayer optics materials
Medvedev, Viacheslav; Yakshin, Andrey; van de Kruijs, Robbert Wilhelmus Elisabeth; Bijkerk, Frederik
2015-01-01
We have evaluated the prospects of phosphorus-based compounds in extreme ultraviolet multilayer optics. Boron phosphide (BP) is suggested to be used as a spacer material in reflective multilayer optics operating just above the L-photoabsorption edge of P (λ ≈9.2 nm). Mo, Ag, Ru, Rh, and Pd were
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Fabrication of Copper-Rich Cu-Al Alloy Using the Wire-Arc Additive Manufacturing Process
Dong, Bosheng; Pan, Zengxi; Shen, Chen; Ma, Yan; Li, Huijun
2017-12-01
An innovative wire-arc additive manufacturing (WAAM) process is used to fabricate Cu-9 at. pct Al on pure copper plates in situ, through separate feeding of pure Cu and Al wires into a molten pool, which is generated by the gas tungsten arc welding (GTAW) process. After overcoming several processing problems, such as opening the deposition molten pool on the extremely high-thermal conductive copper plate and conducting the Al wire into the molten pool with low feed speed, the copper-rich Cu-Al alloy was successfully produced with constant predesigned Al content above the dilution-affected area. Also, in order to homogenize the as-fabricated material and improve the mechanical properties, two further homogenization heat treatments at 1073 K (800 °C) and 1173 K (900 °C) were applied. The material and mechanical properties of as-fabricated and heat-treated samples were compared and analyzed in detail. With increased annealing temperatures, the content of precipitate phases decreased and the samples showed gradual improvements in both strength and ductility with little variation in microstructures. The present research opened a gate for in-situ fabrication of Cu-Al alloy with target chemical composition and full density using the additive manufacturing process.
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Enhancement of oxidation resistance in Cu and Cu(Al) thin layers
Energy Technology Data Exchange (ETDEWEB)
Horvath, Z.E.; Peto, G. E-mail: peto@mfa.kfki.hu; Paszti, Z.; Zsoldos, E.; Szilagyi, E.; Battistig, G.; Lohner, T.; Molnar, G.L.; Gyulai, J
1999-01-02
High conductivity and good resistance to electromigration makes copper a promising interconnect material in microelectronics. However, one of its disadvantages is the poor corrosion resistance. Two methods of passivation are investigated and compared: Al alloying and BF{sub 2}{sup +} ion implantation. X-ray diffraction (XRD) and Rutherford Backscattering Spectrometry (RBS) show the oxidation inhibition of both methods, but the different ratio of CuO{sub 2} to CuO phases suggests different mechanisms of passivation. There are no definite oxide lines in the XRD spectrum of the implanted and annealed Cu(Al) sample, so the presence of Al and the implantation together give increased protection against oxidation. The difference between the two mechanisms of oxidation inhibition is discussed briefly.
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Heteroepitaxial growth of strained multilayer thin films of high-temperature superconductors
International Nuclear Information System (INIS)
Gross, R.; Gupta, A.; Olsson, E.; Segmueller, A.; Koren, G.
1991-01-01
Recently, the heteroepitaxial growth of multilayer structures of different copper oxide superconductors has been reported by several groups. In general, two different types of multilayer structures should be distinguished. The first kind of mulitlayer is formed by high-T c materials having the same crystal structure and almost the same lattice constants, as for example ReBa 2 Cu 3 O 7 (Re=rare earth) multilayers with alternating Re-elements. In these multilayers the two different rare earth copper oxides (Y/Dy, Y/Pr) have the same orthorhombic unit cell. Due to the very similar lattice constants, the misfit strain is easily accommodated without the formation of defects. The second kind of multilayer is formed by layers of materials having different crystal structure and lattice parameters. In these multilayers the misfit can be coherently accommodated below a critical modulation thickness as discussed below. This renders possible the heteroepitaxial growth of strained multilayer structures, both of two copper oxides of different crystal structure, as has been demonstrated recently for the system YBa 2 Cu 3 O 7-δ /Nd 1.83 Ce 0.17 CuO x , and of superconducting copper oxides and insulating materials. For multilayers of different copper oxides, a combination of almost all high-Tc materials should be possible, since the presence of the CuO 2 sheets in these materials results in similar lattice constants in their basal planes ('a' and 'b'). (orig./BHO)
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76 FR 76435 - Multilayered Wood Flooring From China
2011-12-07
...)] Multilayered Wood Flooring From China Determinations On the basis of the record \\1\\ developed in the subject... multilayered wood flooring, provided for in subheadings 4409.10, 4409.29, 4412.31, 4412.32, 4412.39, 4412.94... flooring. The following companies are members of the CAHP: Anderson Hardwood Floors, LLC, Fountain Inn, SC...
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Magnetic studies of spin wave excitations in Ni/Au multilayers
International Nuclear Information System (INIS)
Salhi, H.; Chafai, K.; Benkirane, K.; Lassri, H.; Abid, M.; Hlil, E.K.
2010-01-01
Ni/Au multilayers were prepared by the electron beam evaporation method under ultra high vacuum conditions. The multilayer films have a coherent structure with (1 1 1) texture. The magnetic properties of Ni/Au multilayers are examined as a function of Ni layer thickness t Ni . The temperature dependence of the spontaneous magnetization M(T) is well described by a T 3/2 law in all multilayers. A spin wave theory has been used to explain the magnetization versus temperature. Based on this theory, the approximate values for the bulk exchange interaction J b , surface exchange interaction J S and the interlayer coupling strength J I have been obtained for various Ni layer thicknesses.
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Multilayer Cloud Detection with the MODIS Near-Infrared Water Vapor Absorption Band
Wind, Galina; Platnick, Steven; King, Michael D.; Hubanks, Paul A,; Pavolonis, Michael J.; Heidinger, Andrew K.; Yang, Ping; Baum, Bryan A.
2009-01-01
Data Collection 5 processing for the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the NASA Earth Observing System EOS Terra and Aqua spacecraft includes an algorithm for detecting multilayered clouds in daytime. The main objective of this algorithm is to detect multilayered cloud scenes, specifically optically thin ice cloud overlying a lower-level water cloud, that presents difficulties for retrieving cloud effective radius using single layer plane-parallel cloud models. The algorithm uses the MODIS 0.94 micron water vapor band along with CO2 bands to obtain two above-cloud precipitable water retrievals, the difference of which, in conjunction with additional tests, provides a map of where multilayered clouds might potentially exist. The presence of a multilayered cloud results in a large difference in retrievals of above-cloud properties between the CO2 and the 0.94 micron methods. In this paper the MODIS multilayered cloud algorithm is described, results of using the algorithm over example scenes are shown, and global statistics for multilayered clouds as observed by MODIS are discussed. A theoretical study of the algorithm behavior for simulated multilayered clouds is also given. Results are compared to two other comparable passive imager methods. A set of standard cloudy atmospheric profiles developed during the course of this investigation is also presented. The results lead to the conclusion that the MODIS multilayer cloud detection algorithm has some skill in identifying multilayered clouds with different thermodynamic phases
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Characterization of Mo/Si multilayer growth on stepped topographies
van den Boogaard, Toine; Louis, Eric; Zoethout, E.; Goldberg, K.A.; Bijkerk, Frederik
2011-01-01
Mo/Si multilayer mirrors with nanoscale bilayer thicknesses have been deposited on stepped substrate topographies, using various deposition angles. The multilayer morphology at the step-edge region was studied by cross section transmission electron microscopy. A transition from a continuous- to
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A MULTILAYER BIOCHEMICAL DRY DEPOSITION MODEL 1. MODEL FORMULATION
A multilayer biochemical dry deposition model has been developed based on the NOAA Multilayer Model (MLM) to study gaseous exchanges between the soil, plants, and the atmosphere. Most of the parameterizations and submodels have been updated or replaced. The numerical integration ...
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Hot-rolled Process of Multilayered Composite Metal Plate
Directory of Open Access Journals (Sweden)
YU Wei
2017-02-01
Full Text Available For multi-layer plate, it is a difficult problem to increase product yield rate and improve bonding interface quality. A high yield hot-rolled method of multilayered plate was proposed. The raw strips and plate were fixed by argon arc welding. The combined billet was put into a metal box and vacuum pumped, and then heated and rolled by multi passes at the temperature of 1000-1200℃. The 67 layered plate with the thickness of 2.5mm was successfully produced. The interfacial microstructures and diffusion behavior were investigated and analyzed by optical microscopy and scan electronic microscopy. The tensile and shear strength were tested,and the shear fractures were analyzed. The results show that the multilayered plate yield rate is more than 90% by two steps billet combination method and rolling process optimization. The good bonding interface quality is obtained, the shear strength of multilayered plate reaches 241 MPa. Nickel interlayer between 9Cr18 and 1Cr17 can not only prevent the diffusion of carbon, but also improve the microstructure characteristics.
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Tunable photonic multilayer sensors from photo-crosslinkable polymers
Chiappelli, Maria; Hayward, Ryan
2014-03-01
The fabrication of tunable photonic multilayer sensors from stimuli-responsive, photo-crosslinkable polymers will be described. Benzophenone is covalently incorporated as a pendent photo-crosslinker, allowing for facile preparation of multilayer films by sequential spin-coating and crosslinking processes. Copolymer chemistries and layer thicknesses are selected to provide robust multilayer sensors which can show color changes across nearly the full visible spectrum due to the specific stimulus-responsive nature of the hydrated film stack. We will describe how this approach is extended to alternative sensor designs by tailoring the thickness and chemistry of each layer independently, allowing for the preparation of sensors which depend not only on the shift in wavelength of a reflectance peak, but also on the transition between Bragg mirrors and filters. Device design is optimized by photo-patterning sensor arrays on a single substrate, providing more efficient fabrication time as well as multi-functional sensors. Finally, radiation-sensitive multilayers, designed by choosing polymers which will preferentially degrade or crosslink under ionizing radiation, will also be described.
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Young’s modulus of multi-layer microcantilevers
Directory of Open Access Journals (Sweden)
Zhikang Deng
2017-12-01
Full Text Available A theoretical model for calculating the Young’s modulus of multi-layer microcantilevers with a coating is proposed, and validated by a three-dimensional (3D finite element (FE model using ANSYS parametric design language (APDL and atomic force microscopy (AFM characterization. Compared with typical theoretical models (Rayleigh-Ritz model, Euler-Bernoulli (E-B beam model and spring mass model, the proposed theoretical model can obtain Young’s modulus of multi-layer microcantilevers more precisely. Also, the influences of coating’s geometric dimensions on Young’s modulus and resonant frequency of microcantilevers are discussed. The thickness of coating has a great influence on Young’s modulus and resonant frequency of multi-layer microcantilevers, and the coating should be considered to calculate Young’s modulus more precisely, especially when fairly thicker coating is employed.
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Experimental analysis on stress wave in inhomogeneous multi-layered structures
International Nuclear Information System (INIS)
Cho, Yun Ho; Ham, Hyo Sick
1998-01-01
The guided wave propagation in inhomogeneous multi-layered structures is experimentally explored based on theoretical dispersion curves. It turns out that proper selection of incident angle and frequency is critical for guided wave generation in multi-layered structures. Theoretical dispersion curves greatly depend on adhesive zone thickness, layer thickness and material properties. It was possible to determine the adhesive zone thickness of an inhomogeneous multi-layered structure by monitoring experimentally the change of dispersion curves.
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Thermally induced delamination of multilayers
DEFF Research Database (Denmark)
Sørensen, Bent F.; Sarraute, S.; Jørgensen, O.
1998-01-01
Steady-state delamination of multilayered structures, caused by stresses arising during processing due to thermal expansion mismatch, is analyzed by a fracture mechanics model based on laminate theory. It is found that inserting just a few interlayers with intermediate thermal expansion coefficie...... coefficients may be an effective way of reducing the delamination energy release rate. Uneven layer thickness and increasing elastic mismatch are shown to raise the energy release rate. Experimental work confirms important trends of the model.......Steady-state delamination of multilayered structures, caused by stresses arising during processing due to thermal expansion mismatch, is analyzed by a fracture mechanics model based on laminate theory. It is found that inserting just a few interlayers with intermediate thermal expansion...
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International Nuclear Information System (INIS)
Chrzan, D.C.; Dugger, M.; Follstaedt, D.M.; Friedman, Lawrence H.; Friedmann, T.A.; Knapp, J.A.; McCarty, K.F.; Medlin, D.L.; Mirkarimi, P.B.; Missert, N.; Newcomer, P.P.; Sullivan, J.P.; Tallant, D.R.
1999-01-01
We have developed a new multilayer a-tC material that is thick stress-free, adherent, low friction, and with hardness and stiffness near that of diamond. The new a-tC material is deposited by J pulsed-laser deposition (PLD) at room temperature, and fully stress-relieved by a short thermal anneal at 600 ampersand deg;C. A thick multilayer is built up by repeated deposition and annealing steps. We measured 88 GPa hardness, 1100 GPa Young's modulus, and 0.1 friction coefficient (under high load). Significantly, these results are all well within the range reported for crystalline diamond. In fact, this material, if considered separate from crystalline diamond, is the 2nd hardest material known to man. Stress-free a-tC also has important advantages over thin film diamond; namely, it is smooth, processed at lower temperature, and can be grown on a much broader range of substrates. This breakthrough will enable a host of applications that we are actively pursuing in MEMs, sensors, LIGA, etc
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Multilayered sulphonated polysulfone/silica composite membranes for fuel cell applications
International Nuclear Information System (INIS)
Padmavathi, Rajangam; Karthikumar, Rajendhiran; Sangeetha, Dharmalingam
2012-01-01
Highlights: ► Multilayered membranes were fabricated with SPSu. ► Aminated polysulfone and silica were used as the layers in order to prevent the crossover of methanol. ► The methanol permeability and selectivity ratio proved a strong influence on DMFC application. ► The suitability of the multilayered membranes was studied in the lab made set-ups of PEMFC and DMFC. - Abstract: Polymer electrolyte membranes used in proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) suffer from low dimensional stability. Hence multilayered membranes using sulfonated polysulfone (SPSu) and silica (SiO 2 ) were fabricated to alter such properties. The introduction of an SiO 2 layer between two layers of SPSu to form the multilayered composite membrane enhanced its dimensional stability, but slightly lowered its proton conductivity when compared to the conventional SPSu/SiO 2 composite membrane. Additionally, higher water absorption, lower methanol permeability and higher flame retardancy were also observed in this newly fabricated multilayered membrane. The performance evaluation of the 2 wt% SiO 2 loaded multilayered membrane in DMFC showed a maximum power density of 86.25 mW cm −2 , which was higher than that obtained for Nafion 117 membrane (52.8 mW cm −2 ) in the same single cell test assembly. Hence, due to the enhanced dimensional stability, reduced methanol permeability and higher maximum power density, the SPSu/SiO 2 /SPSu multilayered membrane can be a viable and a promising candidate for use as an electrolyte membrane in DMFC applications, when compared to Nafion.
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The multilayer nanoparticles formed by layer by layer approach for cancer-targeting therapy.
Oh, Keun Sang; Lee, Hwanbum; Kim, Jae Yeon; Koo, Eun Jin; Lee, Eun Hee; Park, Jae Hyung; Kim, Sang Yoon; Kim, Kwangmeyung; Kwon, Ick Chan; Yuk, Soon Hong
2013-01-10
The multilayer nanoparticles (NPs) were prepared for cancer-targeting therapy using the layer by layer approach. When drug-loaded Pluronic NPs were mixed with vesicles (liposomes) in the aqueous medium, Pluronic NPs were incorporated into the vesicles to form the vesicle NPs. Then, the multilayer NPs were formed by freeze-drying the vesicle NPs in a Pluronic aqueous solution. The morphology and size distribution of the multilayer NPs were observed using a TEM and a particle size analyzer. In order to apply the multilayer NPs as a delivery system for docetaxel (DTX), which is a model anticancer drug, the release pattern of the DTX was observed and the tumor growth was monitored by injecting the multilayer NPs into the tail veins of tumor (squamous cell carcinoma)-bearing mice. The cytotoxicity of free DTX (commercial DTX formulation (Taxotere®)) and the multilayer NPs was evaluated using MTT assay. We also evaluated the tumor targeting ability of the multilayer NPs using magnetic resonance imaging. The multilayer NPs showed excellent tumor targetability and antitumor efficacy in tumor-bearing mice, caused by the enhanced permeation and retention (EPR) effect. These results suggest that the multilayer NPs could be a potential drug delivery system for cancer-targeting therapy. Copyright © 2012 Elsevier B.V. All rights reserved.
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Hot-electrons-induced ultrafast demagnitization in Co/Pt multilayers
Bergeard, N.; Hehn, M.; Mangin, S.; Lengaigne, G.; Montaigne, F.; Lalieu, M. L. M.; Koopmans, B.; Malinowski, G.
2016-01-01
Using specially engineered structures to tailor the optical absorption in a metallic multilayer, we analyze the magnetization dynamics of a Co/Pt multilayer buried below a thick Cu layer. We demonstrate that hot electrons alone can very efficiently induce ultrafast demagnetization. Simulations based
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Giant magnetoresistance of hysteresis-free Cu/Co-based multilayers
International Nuclear Information System (INIS)
Huetten, A.; Hempel, T.; Schepper, W.; Kleineberg, U.; Reiss, G.
2001-01-01
It has been demonstrated that hysteresis-free multilayers based on {Cu/Co} and {Cu/Ni 57 Co 43 } can be experimentally realized obtaining room temperature GMR effect amplitudes from 6.5% up to 20%. A critical window for the layer thickness for hysteresis-free GMR curves can be achieved for both systems, ranging from 0.38 to 0.45 nm and 0.59 to 0.7 nm, respectively. The corresponding sensitivities range from 0.075 up to 0.114%/Oe, but are still below that of normal {Cu/Co} multilayers. Hysteresis-free multilayers based on these systems are stable up to 180 deg. C upon isochronal annealing. It is shown that hysteresis-free {Cu/Co or Ni 57 Co 43 }-multilayers are neither a solution to achieve good temperature stability nor a higher sensitivity compared with normal ones and hence are not candidates for application
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Self-assembled metal nano-multilayered film prepared by co-sputtering method
Xie, Tianle; Fu, Licai; Qin, Wen; Zhu, Jiajun; Yang, Wulin; Li, Deyi; Zhou, Lingping
2018-03-01
Nano-multilayered film is usually prepared by the arrangement deposition of different materials. In this paper, a self-assembled nano-multilayered film was deposited by simultaneous sputtering of Cu and W. The Cu/W nano-multilayered film was accumulated by W-rich layer and Cu-rich layer. Smooth interfaces with consecutive composition variation and semi-coherent even coherent relationship were identified, indicating that a spinodal-like structure with a modulation wavelength of about 20 nm formed during co-deposition process. The participation of diffusion barrier element, such as W, is believed the essential to obtain the nano-multilayered structure besides the technological parameters.
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Analytic theory of alternate multilayer gratings operating in single-order regime.
Yang, Xiaowei; Kozhevnikov, Igor V; Huang, Qiushi; Wang, Hongchang; Hand, Matthew; Sawhney, Kawal; Wang, Zhanshan
2017-07-10
Using the coupled wave approach (CWA), we introduce the analytical theory for alternate multilayer grating (AMG) operating in the single-order regime, in which only one diffraction order is excited. Differing from previous study analogizing AMG to crystals, we conclude that symmetrical structure, or equal thickness of the two multilayer materials, is not the optimal design for AMG and may result in significant reduction in diffraction efficiency. The peculiarities of AMG compared with other multilayer gratings are analyzed. An influence of multilayer structure materials on diffraction efficiency is considered. The validity conditions of analytical theory are also discussed.
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Multilayer porous UHMWPE scaffolds for bone defects replacement
International Nuclear Information System (INIS)
Maksimkin, A.V.; Senatov, F.S.; Anisimova, N.Yu.; Kiselevskiy, M.V.; Zalepugin, D.Yu.; Chernyshova, I.V.; Tilkunova, N.A.; Kaloshkin, S.D.
2017-01-01
Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79 ± 2%; the pore size range was 80–700 μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility - Highlights: • Porous UHMWPE scaffold mimics cancellous bone architecture, maintaining its flexibility. • Multilayer UHMWPE scaffold is able to simulate different types of bone tissue. • Fixation of scaffolds in the bone provides through ingrowths of the connective tissue into pores. • Multilayer UHMWPE scaffolds can be used for the formation of bone implants.
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Multilayer porous UHMWPE scaffolds for bone defects replacement
Energy Technology Data Exchange (ETDEWEB)
Maksimkin, A.V. [National University of Science and Technology “MISIS”, Moscow (Russian Federation); Senatov, F.S., E-mail: senatov@misis.ru [National University of Science and Technology “MISIS”, Moscow (Russian Federation); Anisimova, N.Yu.; Kiselevskiy, M.V. [National University of Science and Technology “MISIS”, Moscow (Russian Federation); N.N. Blokhin Russian Cancer Research Center, Moscow (Russian Federation); Zalepugin, D.Yu.; Chernyshova, I.V.; Tilkunova, N.A. [State Plant of Medicinal Drugs, Moscow (Russian Federation); Kaloshkin, S.D. [National University of Science and Technology “MISIS”, Moscow (Russian Federation)
2017-04-01
Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79 ± 2%; the pore size range was 80–700 μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility - Highlights: • Porous UHMWPE scaffold mimics cancellous bone architecture, maintaining its flexibility. • Multilayer UHMWPE scaffold is able to simulate different types of bone tissue. • Fixation of scaffolds in the bone provides through ingrowths of the connective tissue into pores. • Multilayer UHMWPE scaffolds can be used for the formation of bone implants.
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Elastic properties of suspended multilayer WSe{sub 2}
Energy Technology Data Exchange (ETDEWEB)
Zhang, Rui, E-mail: rui.zhang@ed.ac.uk; Cheung, Rebecca [Scottish Microelectronics Centre, Alexander Crum Brown Road, The University of Edinburgh, King' s Buildings, Edinburgh EH9 3FF (United Kingdom); Koutsos, Vasileios [Institute for Materials and Processes, School of Engineering, The University of Edinburgh, King' s Buildings, Edinburgh EH9 3FB (United Kingdom)
2016-01-25
We report the experimental determination of the elastic properties of suspended multilayer WSe{sub 2}, a promising two-dimensional (2D) semiconducting material combined with high optical quality. The suspended WSe{sub 2} membranes have been fabricated by mechanical exfoliation of bulk WSe{sub 2} and transfer of the exfoliated multilayer WSe{sub 2} flakes onto SiO{sub 2}/Si substrates pre-patterned with hole arrays. Then, indentation experiments have been performed on these membranes with an atomic force microscope. The results show that the 2D elastic modulus of the multilayer WSe{sub 2} membranes increases linearly while the prestress decreases linearly as the number of layers increases. The interlayer interaction in WSe{sub 2} has been observed to be strong enough to prevent the interlayer sliding during the indentation experiments. The Young's modulus of multilayer WSe{sub 2} (167.3 ± 6.7 GPa) is statistically independent of the thickness of the membranes, whose value is about two thirds of other most investigated 2D semiconducting transition metal dichalcogenides, namely, MoS{sub 2} and WS{sub 2}. Moreover, the multilayer WSe{sub 2} can endure ∼12.4 GPa stress and ∼7.3% strain without fracture or mechanical degradation. The 2D WSe{sub 2} can be an attractive semiconducting material for application in flexible optoelectronic devices and nano-electromechanical systems.
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CuAlO2 and CuAl2O4 thin films obtained by stacking Cu and Al films using physical vapor deposition
Castillo-Hernández, G.; Mayén-Hernández, S.; Castaño-Tostado, E.; DeMoure-Flores, F.; Campos-González, E.; Martínez-Alonso, C.; Santos-Cruz, J.
2018-06-01
CuAlO2 and CuAl2O4 thin films were synthesized by the deposition of the precursor metals using the physical vapor deposition technique and subsequent annealing. Annealing was carried out for 4-6 h in open and nitrogen atmospheres respectively at temperatures of 900-1000 °C with control of heating and cooling ramps. The band gap measurements ranged from 3.3 to 4.5 eV. Electrical properties were measured using the van der Pauw technique. The preferred orientations of CuAlO2 and CuAl2O4 were found to be along the (1 1 2) and (3 1 1) planes, respectively. The phase percentages were quantified using a Rietveld refinement simulation and the energy dispersive X-ray spectroscopy indicated that the composition is very close to the stoichiometry of CuAlO2 samples and with excess of aluminum and deficiency of copper for CuAl2O4 respectively. High resolution transmission electron microscopy identified the principal planes in CuAlO2 and in CuAl2O4. Higher purities were achieved in nitrogen atmosphere with the control of the cooling ramps.
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Layer-by-layer strippable Ag multilayer films fabricated by modular assembly.
Li, Yan; Chen, Xiaoyan; Li, Qianqian; Song, Kai; Wang, Shihui; Chen, Xiaoyan; Zhang, Kai; Fu, Yu; Jiao, Yong-Hua; Sun, Ting; Liu, Fu-Chun; Han, En-Hou
2014-01-21
We have developed a new method to fabricate multilayer films, which uses prepared thin films as modular blocks and transfer as operation mode to build up multilayer structures. In order to distinguish it from the in situ fabrication manner, this method is called modular assembly in this study. On the basis of such concept, we have fabricated a multilayer film using the silver mirror film as the modular block and poly(lactic acid) as the transfer tool. Due to the special double-layer structure of the silver mirror film, the resulting multilayer film had a well-defined stratified architecture with alternate porous/compact layers. As a consequence of the distinct structure, the interaction between the adjacent layers was so weak that the multilayer film could be layer-by-layer stripped. In addition, the top layer in the film could provide an effective protection on the morphology and surface property of the underlying layers. This suggests that if the surface of the film was deteriorated, the top layer could be peeled off and the freshly exposed surface would still maintain the original function. The successful preparation of the layer-by-layer strippable silver multilayer demonstrates that modular assembly is a feasible and effective method to build up multilayer films capable of creating novel and attractive micro/nanostructures, having great potential in the fabrication of nanodevices and coatings.
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Swift heavy ion irradiation effects in Pt/C and Ni/C multilayers
Gupta, Ajay; Pandita, Suneel; Avasthi, D. K.; Lodha, G. S.; Nandedkar, R. V.
1998-12-01
Irradiation effects of 100 MeV Ag ion irradiation on Ni/C and Pt/C multilayers have been studied using X-ray reflectivity measurements. Modifications are observed in both the multilayers at (dE/dx)e values much below the threshold values for Ni and Pt. This effect is attributed to the discontinuous nature of the metal layers. In both the multilayers interfacial roughness increases with irradiation dose. While Ni/C multilayers exhibit large ion-beam induced intermixing, no observable intermixing is observed in the case of Pt/C multilayer. This difference in the behavior of the two systems suggests a significant role for chemically guided defect motion in the mixing process associated with swift heavy ion irradiation.
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Multiperiodicity in plasmonic multilayers: General description and diversity of topologies
DEFF Research Database (Denmark)
Orlov, Alexey A.; Krylova, Anastasia K.; Zhukovsky, Sergei
2014-01-01
We introduce multiperiodicity in periodicmetal-dielectric multilayers by stacking more than two types of metal and/or dielectric layers into the unit cell. A simple way to characterize arbitrary multiperiodic multilayers using permutation vectors is suggested and employed. Effects of multiperiodi...... of multiperiodicity up to its fourth order are investigated. We demonstrate that various topologies of multiple-sheet isofrequency and dispersion surfaces exist for such plasmonic multilayers, including a photonic realization of nontrivial isolated Dirac cones....
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Docetaxel-loaded multilayer nanoparticles with nanodroplets for cancer therapy.
Oh, Keun Sang; Kim, Kyungim; Yoon, Byeong Deok; Lee, Hye Jin; Park, Dal Yong; Kim, Eun-Yeong; Lee, Kiho; Seo, Jae Hong; Yuk, Soon Hong
2016-01-01
A mixture of docetaxel (DTX) and Solutol(®) HS 15 (Solutol) transiently formed nanodroplets when it was suspended in an aqueous medium. However, nanodroplets that comprised DTX and Solutol showed a rapid precipitation of DTX because of their unstable characteristics in the aqueous medium. The incorporation of nanodroplets that comprised DTX and Solutol through vesicle fusion and subsequent stabilization was designed to prepare multilayer nanoparticles (NPs) with a DTX-loaded Solutol nanodroplet (as template NPs) core for an efficient delivery of DTX as a chemotherapeutic drug. As a result, the DTX-loaded Solutol nanodroplets (~11.7 nm) were observed to have an increased average diameter (from 11.7 nm to 156.1 nm) and a good stability of the hydrated NPs without precipitation of DTX by vesicle fusion and multilayered structure, respectively. Also, a long circulation of the multilayer NPs was observed, and this was due to the presence of Pluronic F-68 on the surface of the multilayer NPs. This led to an improved antitumor efficacy based on the enhanced permeation and retention effect. Therefore, this study indicated that the multilayer NPs have a considerable potential as a drug delivery system with an enhanced therapeutic efficacy by blood circulation and with low side effects.
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Decomposition of multilayer benzene and n-hexane films on vanadium.
Souda, Ryutaro
2015-09-21
Reactions of multilayer hydrocarbon films with a polycrystalline V substrate have been investigated using temperature-programmed desorption and time-of-flight secondary ion mass spectrometry. Most of the benzene molecules were dissociated on V, as evidenced by the strong depression in the thermal desorption yields of physisorbed species at 150 K. The reaction products dehydrogenated gradually after the multilayer film disappeared from the surface. Large amount of oxygen was needed to passivate the benzene decomposition on V. These behaviors indicate that the subsurface sites of V play a role in multilayer benzene decomposition. Decomposition of the n-hexane multilayer films is manifested by the desorption of methane at 105 K and gradual hydrogen desorption starting at this temperature, indicating that C-C bond scission precedes C-H bond cleavage. The n-hexane dissociation temperature is considerably lower than the thermal desorption temperature of the physisorbed species (140 K). The n-hexane multilayer morphology changes at the decomposition temperature, suggesting that a liquid-like phase formed after crystallization plays a role in the low-temperature decomposition of n-hexane.
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Single layer and multilayer wear resistant coatings of (Ti,Al)N: a review
International Nuclear Information System (INIS)
PalDey, S.; Deevi, S.C.
2003-01-01
We review the status of (Ti,Al)N based coatings obtained by various physical vapor deposition (PVD) techniques and compare their properties. PVD techniques based on sputtering and cathodic arc methods are widely used to deposit wear resistant (Ti,Al)N coatings. These techniques were further modified to improve the metal ionization rate and to eliminate macrodroplets from plasma streams. We summarize manufacture of target/cathode, substrate materials for deposition of coatings, deposition parameters, and the effect of deposition parameters on the physical and mechanical properties of (Ti,Al)N coatings. It is shown that (Ti,Al)N coatings by PVD enhance the wear, thermal, and oxidation resistance of a wide variety of tool materials. We discuss the wear resistant properties of (Ti,Al)N for various machining applications as compared with coatings such as TiN, Ti(C,N) and (Ti,Zr)N. High hardness (∼28-32 GPa), relatively low residual stress (∼5 GPa), superior oxidation resistance, high hot hardness, and low thermal conductivity make (Ti,Al)N coatings most desirable in dry machining and machining of abrasive alloys at high speeds. Multicomponent coatings based on different metallic and nonmetallic elements combine the benefit of individual components leading to a further refinement of coating properties. Alloying additions such as Cr and Y drastically improve the oxidation resistance, Zr and V improve the wear resistance, whereas, Si increases the hardness and resistance to chemical reactivity of the film. Addition of boron improves the abrasive wear behavior of Ti-Al based coatings due to the formation of TiB 2 and BN phases depending on the deposition conditions. Hafnium based nitrides and carbides have potential for resistance to flank and crater wear. The presence of a large number of interfaces between individual layers of a multilayered structure results in a drastic increase in hardness and strength. (Ti,Al)N multilayer super lattice coatings with lattice
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International Nuclear Information System (INIS)
Ahn, Ji Young; Lee, Hyung Woo; Kim, Jong Man; Kim, Soo Hyung; Kim, Sang Beom; Kim, Ji Hoon; Jang, Nam Su; Kim, Dae Hyun
2016-01-01
The interfacial contact area between the fuel and oxidizer components plays an important role in determining the combustion reactivity of nanothermite composites. In addition, the development of compact and reliable ignition methods can extend the applicability of nanothermite composites to various thermal engineering fields. In this study we report the development of a micro-chip initiator with controlled combustion reactivity using concepts usually applied to microelectromechanical systems (MEMS) and simple nanofabrication processes. The nanothermite composites fabricated in this study consisted of aluminum nanoparticles (Al NPs) as the fuel and copper oxide nanoparticles (CuO NPs) as the oxidizer accumulated on a silicon oxide substrate with a serpentine-shaped gold (Au) electrode. The micro-chip initiator rapidly ignited and exploded when minimal current was supplied. The effects of stacking structures of Al and CuO-based multilayers on the combustion properties were systematically investigated in terms of the pressurization rate, peak explosion time, and heat flow. Pressurization rates of 0.004–0.025 MPa μs −1 and heat flows of 2.0–3.8 kJ g −1 with a commonly fast response time of less than 20 ms could be achieved by simply changing the interfacial structures of the Al and CuO multilayers. The controllability of combustion reactivity of micro-chip initiator can be made for general nanothermite composites composed of Al and various metal oxides (e.g. Fe 2 O 3 , CuO, KMnO 4 , etc). The micro-chip initiator fabricated in this study was reliable, compact, and proved to be a versatile platform, exhibiting controlled combustion reactivity and fast response time, which could be used for various civilian and military thermal engineering applications, such as in initiators and propulsion, welding, and ordinance systems. (paper)
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Energy Technology Data Exchange (ETDEWEB)
Guzmán-Vargas, Ariel, E-mail: aguzmanv@ipn.mx [Instituto Politécnico Nacional, ESIQIE-SEPI-DIQI, Laboratorio de Investigación en Materiales Porosos, Catálisis Ambiental y Química Fina (LiMpCa-QuF), UPALM Edif. 7 P.B. Zacatenco, GAM, México, D.F.07738 (Mexico); Lima, Enrique [Instituto de Investigaciones en Materiales-UNAM, Circuito exterior s/n, Cd. Universitaria, Del. Coyoacán, México, D.F. 04510 (Mexico); Uriostegui-Ortega, Gisselle A. [Instituto Politécnico Nacional, ESIQIE-SEPI-DIQI, Laboratorio de Investigación en Materiales Porosos, Catálisis Ambiental y Química Fina (LiMpCa-QuF), UPALM Edif. 7 P.B. Zacatenco, GAM, México, D.F.07738 (Mexico); Oliver-Tolentino, Miguel A. [Instituto Politécnico Nacional, Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada, Calzada Legaria 694, Col. Irrigación, México, D.F. 11500 (Mexico); Rodríguez, Esaú E. [Departamento de Química, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Av. Instituto Politécnico Nacional 2580, Col. San Pedro Zacatenco, México, D.F. 07360 (Mexico)
2016-02-15
Graphical abstract: - Highlights: • LDH Cu/Al material showed high adsorption capacity. • Adsorption occurs by π–π interactions from the aromatic ring on the surface. • Adsorption mechanism fits to pseudo-second order model. • The photodegradation is due to the ·OH radical formation. - Abstract: Uncalcined Cu/Al LDH was studied as adsorbent and photocatalyst in the adsorption and subsequent photodegradation of methyl violet 2B dye (MV2B). Physicochemical characterization was carried out by XRD, FTIR, UV–vis, including photoactive properties, DSC/TGA and SEM. Kinetic and thermodynamic models showed great affinity and sorption capacity, the maximum adsorption capacity was 361.0 mg g{sup −1} obtained by Langmuir model, in addition, the results showed that the dye was adsorbed on the LDH surface. Photocatalytic activity was evaluated in the MV2B dye photodegradation process, and it was confirmed by the presence ·OH radicals monitored by EPR spin trapping technique, additionally, COD and TOC parameters were measured, {sup 13}C NMR showed differences for the adsorbed and photodegraded samples.
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International Nuclear Information System (INIS)
Guzmán-Vargas, Ariel; Lima, Enrique; Uriostegui-Ortega, Gisselle A.; Oliver-Tolentino, Miguel A.; Rodríguez, Esaú E.
2016-01-01
Graphical abstract: - Highlights: • LDH Cu/Al material showed high adsorption capacity. • Adsorption occurs by π–π interactions from the aromatic ring on the surface. • Adsorption mechanism fits to pseudo-second order model. • The photodegradation is due to the ·OH radical formation. - Abstract: Uncalcined Cu/Al LDH was studied as adsorbent and photocatalyst in the adsorption and subsequent photodegradation of methyl violet 2B dye (MV2B). Physicochemical characterization was carried out by XRD, FTIR, UV–vis, including photoactive properties, DSC/TGA and SEM. Kinetic and thermodynamic models showed great affinity and sorption capacity, the maximum adsorption capacity was 361.0 mg g"−"1 obtained by Langmuir model, in addition, the results showed that the dye was adsorbed on the LDH surface. Photocatalytic activity was evaluated in the MV2B dye photodegradation process, and it was confirmed by the presence ·OH radicals monitored by EPR spin trapping technique, additionally, COD and TOC parameters were measured, "1"3C NMR showed differences for the adsorbed and photodegraded samples.
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Clustering network layers with the strata multilayer stochastic block model.
Stanley, Natalie; Shai, Saray; Taylor, Dane; Mucha, Peter J
2016-01-01
Multilayer networks are a useful data structure for simultaneously capturing multiple types of relationships between a set of nodes. In such networks, each relational definition gives rise to a layer. While each layer provides its own set of information, community structure across layers can be collectively utilized to discover and quantify underlying relational patterns between nodes. To concisely extract information from a multilayer network, we propose to identify and combine sets of layers with meaningful similarities in community structure. In this paper, we describe the "strata multilayer stochastic block model" (sMLSBM), a probabilistic model for multilayer community structure. The central extension of the model is that there exist groups of layers, called "strata", which are defined such that all layers in a given stratum have community structure described by a common stochastic block model (SBM). That is, layers in a stratum exhibit similar node-to-community assignments and SBM probability parameters. Fitting the sMLSBM to a multilayer network provides a joint clustering that yields node-to-community and layer-to-stratum assignments, which cooperatively aid one another during inference. We describe an algorithm for separating layers into their appropriate strata and an inference technique for estimating the SBM parameters for each stratum. We demonstrate our method using synthetic networks and a multilayer network inferred from data collected in the Human Microbiome Project.
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Multilayer composition coatings for cutting tools: formation and performance properties
Tabakov, Vladimir P.; Vereschaka, Anatoly S.; Vereschaka, Alexey A.
2018-03-01
The paper considers the concept of a multi-layer architecture of the coating in which each layer has a predetermined functionality. Latest generation of coatings with multi-layered architecture for cutting tools secure a dual nature of the coating, in which coatings should not only improve the mechanical and physical characteristics of the cutting tool material, but also reduce the thermo-mechanical effect on the cutting tool determining wear intensity. Here are presented the results of the development of combined methods of forming multi-layer coatings with improved properties. Combined method of forming coatings using a pulsed laser allowed reducing excessively high levels of compressive residual stress and increasing micro hardness of the multilayered coatings. The results in testing coated HSS tools showed that the use of additional pulse of laser processing increases tool life up to 3 times. Using filtered cathodic vacuum arc deposition for the generation of multilayer coatings based on TiAlN compound has increased the wear-resistance of carbide tools by 2 fold compared with tool life of cutting tool with commercial TiN coatings. The aim of this study was to develop an innovative methodological approach to the deposition of multilayer coatings for cutting tools with functional architectural selection, properties and parameters of the coating based on sound knowledge of coating failure in machining process.
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Multiple analysis of an unknown optical multilayer coating
International Nuclear Information System (INIS)
Dobrowolski, J.A.; Ho, F.C.; Waldorf, A.
1985-01-01
Results are given of the analysis at five different laboratories of an unknown optical multilayer coating. In all, eleven different analytical and laboratory techniques were applied to the problem. The multilayer nominally consisted of three dielectric and two metallic layers. It was demonstrated convincingly that with present day techniques it is possible to determine the basic structure of such a coating
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Enhancement of the spin Peltier effect in multilayers
Uchida, K.; Iguchi, R.; Daimon, S.; Ramos, R.; Anadón, A.; Lucas, I.; Algarabel, P. A.; Morellón, L.; Aguirre, M. H.; Ibarra, M. R.; Saitoh, E.
2017-05-01
The spin Peltier effect (SPE), heat-current generation as a result of spin-current injection, has been investigated in alternately stacked Pt/Fe3O4 multilayer films. The temperature modulation induced by the SPE in the [Pt/Fe3O4]×n films was found to be significantly enhanced with increasing the number of Pt/Fe3O4 bilayers n . This SPE enhancement is much greater than that expected for a simple stack of independent Pt/Fe3O4 bilayers. The observed n dependence of the SPE can be explained by introducing spin-current redistribution in the multilayer films in the thickness direction, in a manner similar to the enhancement of the spin Seebeck effect in multilayers.
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Energy Technology Data Exchange (ETDEWEB)
Huang, Zhenying, E-mail: zhyhuang@bjtu.edu.cn [Institute of Material Science and Engineering, School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Institut PPRIME, Département de Physique et Mécanique des Matériaux, CNRS, Université de Poitiers, ENSMA, UPR 3346, SP2MI, Téléport 2 Boulevard Marie et Pierre Curie, BP 30179, F86962 Futuroscope Chasseneuil Cedex (France); Bonneville, Joel [Institut PPRIME, Département de Physique et Mécanique des Matériaux, CNRS, Université de Poitiers, ENSMA, UPR 3346, SP2MI, Téléport 2 Boulevard Marie et Pierre Curie, BP 30179, F86962 Futuroscope Chasseneuil Cedex (France); Zhai, Hongxiang [Institute of Material Science and Engineering, School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Gauthier-Brunet, Veronique [Institut PPRIME, Département de Physique et Mécanique des Matériaux, CNRS, Université de Poitiers, ENSMA, UPR 3346, SP2MI, Téléport 2 Boulevard Marie et Pierre Curie, BP 30179, F86962 Futuroscope Chasseneuil Cedex (France); and others
2014-07-25
Highlights: • Submicro-layered TiC{sub 0.61}/Cu(Al) nanocomposite. • MAX phase. • High yield stress. • Deformation mechanism. - Abstract: A new submicro-layered TiC{sub 0.61}/Cu(Al) composite has been prepared by hot-pressing a mixture of 50 vol.% Ti{sub 3}AlC{sub 2} and 50 vol.% Cu powders at 1150 °C and 30 MPa. It is shown that the initial reinforcement Ti{sub 3}AlC{sub 2} particles have, after synthesis, an unusual microstructure, which consists of submicron-thick layers of TiC{sub 0.61} and Cu(Al) alloy. Both the width of the TiC{sub 0.61} and Cu(Al) layers are ∼150 nm. Thus, the Ti{sub 3}AlC{sub 2} particles are decomposed into the TiC{sub 0.61} phase, while the additional Al atoms provided by Ti{sub 3}AlC{sub 2} diffuse into the molten Cu matrix at high temperature. Compression tests were performed at constant strain rate in the temperature range 20–800 °C. The new designed TiC{sub 0.61}/Cu(Al) composite has both a high yield stress, σ{sub 0.2} measured at 0.2% strain offset, and a high ultimate compressive strength, σ{sub UCS}, which is attributed to strong interface bonding between TiC{sub 0.61} and Cu(Al) phase. For instance, at 20 and 200 °C, σ{sub 0.2} is 770 MPa and 700 MPa, while σ{sub UCS} is 1.18 GPa and 1 GPa, respectively. Plastic deformation takes place in the Cu(Al) matrix. Wavy slip lines are observed indicating that cross-slip could be the dominant deformation mechanism.
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Neutron spin quantum precession using multilayer spin splitters and a phase-spin echo interferometer
International Nuclear Information System (INIS)
Ebisawa, Toru; Tasaki, Seiji; Kawai, Takeshi; Hino, Masahiro; Akiyoshi, Tsunekazu; Achiwa, Norio; Otake, Yoshie; Funahashi, Haruhiko.
1996-01-01
Neutron spin quantum precession by multilayer spin splitter has been demonstrated using a new spin interferometer. The multilayer spin splitter consists of a magnetic multilayer mirror on top, followed by a gap layer and a non magnetic multilayer mirror which are evaporated on a silicon substrate. Using the multilayer spin splitter, a polarized neutron wave in a magnetic field perpendicular to the polarization is split into two spin eigenstates with a phase shift in the direction of the magnetic field. The spin quantum precession is equal to the phase shift, which depends on the effective thickness of the gap layer. The demonstration experiments verify the multilayer spin splitter as a neutron spin precession device as well as the coherent superposition principle of the two spin eigenstates. We have developed a new phase-spin echo interferometer using the multilayer spin splitters. We present successful performance tests of the multilayer spin splitter and the phase-spin echo interferometer. (author)
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Photo-crosslinkable polymers for fabrication of photonic multilayer sensors
Chiappelli, Maria; Hayward, Ryan C.
2013-03-01
We have used photo-crosslinkable polymers to fabricate photonic multilayer sensors. Benzophenone is utilized as a covalently incorporated pendent photo-crosslinker, providing a convenient means of fabricating multilayer films by sequential spin-coating and crosslinking processes. Colorimetric temperature sensors were designed from thermally-responsive, low-refractive index poly(N-isopropylacrylamide) (PNIPAM) and high-refractive index poly(para-methyl styrene) (P pMS). Copolymer chemistries and layer thicknesses were selected to provide robust multilayer sensors which show color changes across nearly the full visible spectrum due to changes in temperature of the hydrated film stack. We have characterized the uniformity and interfacial broadening within the multilayers, the kinetics of swelling and de-swelling, and the reversibility over multiple hydration/dehydration cycles. We also describe how the approach can be extended to alternative sensor designs through the ability to tailor each layer independently, as well as to additional stimuli by selecting alternative copolymer chemistries.
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Energy Technology Data Exchange (ETDEWEB)
Darbari, S; Shahmohammadi, M; Mortazavi, M; Mohajerzadeh, S [Thin Film and Nano-Electronic Laboratory, School of ECE, University of Tehran, Tehran (Iran, Islamic Republic of); Abdi, Y [Nano-Physics Research Laboratory, Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of); Robertson, M; Morrison, T, E-mail: mohajer@ut.ac.ir [Department of Physics, Acadia University, Wolfville, NS (Canada)
2011-09-16
A low-temperature hydrogenation-assisted sequential deposition and crystallization technique is reported for the preparation of nano-scale silicon quantum dots suitable for light-emitting applications. Radio-frequency plasma-enhanced deposition was used to realize multiple layers of nano-crystalline silicon while reactive ion etching was employed to create nano-scale features. The physical characteristics of the films prepared using different plasma conditions were investigated using scanning electron microscopy, transmission electron microscopy, room temperature photoluminescence and infrared spectroscopy. The formation of multilayered structures improved the photon-emission properties as observed by photoluminescence and a thin layer of silicon oxy-nitride was then used for electrical isolation between adjacent silicon layers. The preparation of light-emitting diodes directly on glass substrates has been demonstrated and the electroluminescence spectrum has been measured.
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Highly efficient blazed grating with multilayer coating for tender X-ray energies
Senf, F.; Bijkerk, Frederik; Eggenstein, F.; Gwalt, G.; Huang, Qiushi; van de Kruijs, Robbert Wilhelmus Elisabeth; Kutz, O.; Lemke, S.; Louis, Eric; Mertin, M.; Packe, I.; Rudolph, I.; Schafers, F.; Siewert, F.; Sokolov, A.; Sturm, Jacobus Marinus; Waberski, C.; Wang, Z.; Wolf, J.; Zeschke, T.; Erko, A.
2016-01-01
For photon energies of 1 – 5 keV, blazed gratings with multilayer coating are ideally suited for the suppression of stray and higher orders light in grating monochromators. We developed and characterized a blazed 2000 lines/mm grating coated with a 20 period Cr/C- multilayer. The multilayer
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Energy Technology Data Exchange (ETDEWEB)
Ahmed, Nesreen S. [Department of Chemistry, Faculty of Science, King Abdulaziz University (Saudi Arabia); Surface Chemistry and Catalytic Studies Group, King Abdulaziz University (Saudi Arabia); Menzel, Robert [Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Bio Nano Consulting, The Gridiron Building, One Pancras Square, London N1C 4AG (United Kingdom); Wang, Yifan [Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Garcia-Gallastegui, Ainara [Bio Nano Consulting, The Gridiron Building, One Pancras Square, London N1C 4AG (United Kingdom); Bawaked, Salem M.; Obaid, Abdullah Y.; Basahel, Sulaiman N. [Department of Chemistry, Faculty of Science, King Abdulaziz University (Saudi Arabia); Surface Chemistry and Catalytic Studies Group, King Abdulaziz University (Saudi Arabia); Mokhtar, Mohamed, E-mail: mmokhtar2000@yahoo.com [Department of Chemistry, Faculty of Science, King Abdulaziz University (Saudi Arabia); Surface Chemistry and Catalytic Studies Group, King Abdulaziz University (Saudi Arabia)
2017-02-15
Two efficient catalyst based on CuAl and CoAl layered double hydroxides (LDHs) supported on graphene oxide (GO) for the carbon-carbon coupling (Classic Ullmann Homocoupling Reaction) are reported. The pure and hybrid materials were synthesised by direct precipitation of the LDH nanoparticles onto GO, followed by a chemical, structural and physical characterisation by electron microscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), surface area measurements and X-ray photoelectron spectroscopy (XPS). The GO-supported and unsupported CuAl-LDH and CoAl-LDH hybrids were tested over the Classic Ullman Homocoupling Reaction of iodobenzene. In the current study CuAl- and CoAl-LDHs have shown excellent yields (91% and 98%, respectively) at very short reaction times (25 min). GO provides a light-weight, charge complementary and two-dimensional material that interacts effectively with the 2D LDHs, in turn enhancing the stability of LDH. After 5 re-use cycles, the catalytic activity of the LDH/GO hybrid is up to 2 times higher than for the unsupported LDH. - Graphical abstract: CuAl- and CoAl-LDHs have shown excellent yields (91% and 98%, respectively) at very short reaction times (25 min). GO provides a light-weight, charge complementary, two-dimensional material that interacts effectively with the 2D LDHs, in turn enhancing the stability of LDH. - Highlights: • CuAl LDH/GO and CoAl LDH/GO hybrid materials with different LDH compositions were prepared. • Hybrids were fully characterised and their catalytic efficiency over the Classic Ullman Reaction was studied. • CuAl- and CoAl-LDHs have shown excellent yields (91% and 98%, respectively) in 25 min reaction times. • GO provides a light-weight, charge complementary, two-dimensional material that interacts effectively with the 2D LDHs. • After 5 re-use cycles, the catalytic activity of the LDH/GO hybrid is up to 2 times higher than for the unsupported LDH.
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Simulation of reactive nanolaminates using reduced models: II. Normal propagation
Energy Technology Data Exchange (ETDEWEB)
Salloum, Maher; Knio, Omar M. [Department of Mechanical Engineering, The Johns Hopkins University, Baltimore, MD 21218-2686 (United States)
2010-03-15
Transient normal flame propagation in reactive Ni/Al multilayers is analyzed computationally. Two approaches are implemented, based on generalization of earlier methodology developed for axial propagation, and on extension of the model reduction formalism introduced in Part I. In both cases, the formulation accommodates non-uniform layering as well as the presence of inert layers. The equations of motion for the reactive system are integrated using a specially-tailored integration scheme, that combines extended-stability, Runge-Kutta-Chebychev (RKC) integration of diffusion terms with exact treatment of the chemical source term. The detailed and reduced models are first applied to the analysis of self-propagating fronts in uniformly-layered materials. Results indicate that both the front velocities and the ignition threshold are comparable for normal and axial propagation. Attention is then focused on analyzing the effect of a gap composed of inert material on reaction propagation. In particular, the impacts of gap width and thermal conductivity are briefly addressed. Finally, an example is considered illustrating reaction propagation in reactive composites combining regions corresponding to two bilayer widths. This setup is used to analyze the effect of the layering frequency on the velocity of the corresponding reaction fronts. In all cases considered, good agreement is observed between the predictions of the detailed model and the reduced model, which provides further support for adoption of the latter. (author)
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International Nuclear Information System (INIS)
Lv Weizhong; Liu Bo; Qiu Qi; Wang Fang; Luo Zhongkuan; Zhang Peixin; Wei Shaohui
2009-01-01
Spinel copper aluminate (CuAl 2 O 4 ) nanoparticles were synthesized with the aid of sonication by a precursor approach. The precursors were prepared by sonicating an aqueous solution of copper nitrate, aluminium nitrate, and urea. Upon heating at 900 deg. C for 6 h, the precursor formed nanosized CuAl 2 O 4 particles with an average size of 17 nm and with a surface area of about 110 m 2 g -1 . The nanosized copper aluminate particles as well as the precursors were characterized by elemental analysis, powder X-ray diffraction, transmission electron microscopy (TEM) image with electron diffraction pattern, thermogravimetric analysis, differential scanning calorimeter (DSC), Fourier transform of infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) surface area measurements. The photocatalytic degradation was investigated using methyl orange under the irradiation of Hg lamp (λ > 400 nm). The resulting degradation rates of the methyl orange were measured to be as high as 98% in 2 h.
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Thermal stress prediction in mirror and multilayer coatings.
Cheng, Xianchao; Zhang, Lin; Morawe, Christian; Sanchez Del Rio, Manuel
2015-03-01
Multilayer optics for X-rays typically consist of hundreds of periods of two types of alternating sub-layers which are coated on a silicon substrate. The thickness of the coating is well below 1 µm (tens or hundreds of nanometers). The high aspect ratio (∼10(7)) between the size of the optics and the thickness of the multilayer can lead to a huge number of elements (∼10(16)) for the numerical simulation (by finite-element analysis using ANSYS code). In this work, the finite-element model for thermal-structural analysis of multilayer optics has been implemented using the ANSYS layer-functioned elements. The number of meshed elements is considerably reduced and the number of sub-layers feasible for the present computers is increased significantly. Based on this technique, single-layer coated mirrors and multilayer monochromators cooled by water or liquid nitrogen are studied with typical parameters of heat-load, cooling and geometry. The effects of cooling-down of the optics and heating of the X-ray beam are described. It is shown that the influences from the coating on temperature and deformation are negligible. However, large stresses are induced in the layers due to the different thermal expansion coefficients between the layer and the substrate materials, which is the critical issue for the survival of the optics. This is particularly true for the liquid-nitrogen cooling condition. The material properties of thin multilayer films are applied in the simulation to predict the layer thermal stresses with more precision.
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Status and limitations of multilayer X-ray interference structures
International Nuclear Information System (INIS)
Kortright, J.B.
1996-01-01
Trends in the performance of x-ray multilayer interference structures with periods ranging from 9 to 130 (angstrom) are reviewed. Analysis of near-normal incidence reflectance data vs photon energy reveals that the effective interface with σ in a static Debye-Waller model, describing interdiffusion and roughness, decreases as the multilayer period decreases, and reaches a lower limit of roughly 2 (angstrom). Specular reflectance and diffuse scattering from uncoated and multilayer-coated substrates having different roughness suggest that this lower limit results largely from substrate roughness. The increase in interface width with period thus results from increasing roughness of interdiffusion as the layer thickness increases
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Energy Technology Data Exchange (ETDEWEB)
Dong Yunshan; Yue Jianling; Liu Yan; Li Geyang [State Key Lab of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200030 (China)
2006-11-21
By reactively sputtering Zr and Al{sub 2}O{sub 3} targets in a gaseous mixture of Ar and N{sub 2}, ZrN/AlON nanomultilayers were synthesized to study the crystallization conditions for AlON layers and how they influence the characteristics of multilayers. The composition analysis indicated that some of the oxygen atoms were replaced by nitrogen atoms in Al{sub 2}O{sub 3}, leading to the formation of aluminium oxynitride, AlON, during the procedure of the Al{sub 2}O{sub 3} target being sputtered in the gaseous mixture. Further investigations showed that when their thickness was limited to less than 1 nm, amorphous AlON layers were crystallized under the template effects of crystalline ZrN layers, and then coherent interfaces formed as a result. Correspondingly, the multilayers were remarkably strengthened with hardness approaching a maximum of 33 GPa. After the layer thickness of AlON exceeded the critical value of 1 nm, the subsequently deposited AlON grew amorphously and blocked the epitaxial growth of multilayers, accompanied by the decline of hardness. Yet, on the other hand, the integrated hardness of multilayers was not sensitive to the thickness of the ZrN template layers and its value was maintained a bit higher than 30 GPa in a wide range of ZrN layer thickness variations.
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Rocket flight of a multilayer coated high-density EUV toroidal grating
Keski-Kuha, Ritva A. M.; Thomas, Roger J.; Davila, Joseph M.
1992-01-01
A multilayer coated high density toroidal grating was flown on a sounding rocket experiment in the Solar EUV Rocket Telescope and Spectrograph (SERTS) instrument. To our knowledge this is the first space flight of a multilayer coated grating. Pre-flight performance evaluation showed that the application of a 10-layer Ir/Si multilayer coating to the 3600 l/mm blazed toroidal replica grating produced a factor of 9 enhancement in peak efficiency near the design wavelength around 30 nm in first order over the standard gold coating, with a measured EUV efficiency that peaked at 3.3 percent. In addition, the grating's spectral resolution of better than 5000 was maintained. The region of enhanced grating efficiency due to the multilayer coating is clearly evident in the flight data. Within the bandpass of the multilayer coating, the recorded film densities were roughly equivalent to those obtained with a factor of six longer exposure on the previous flight of the SERTS instrument.
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Mathematical Formulation of Multilayer Networks
De Domenico, Manlio; Solé-Ribalta, Albert; Cozzo, Emanuele; Kivelä, Mikko; Moreno, Yamir; Porter, Mason A.; Gómez, Sergio; Arenas, Alex
2013-10-01
A network representation is useful for describing the structure of a large variety of complex systems. However, most real and engineered systems have multiple subsystems and layers of connectivity, and the data produced by such systems are very rich. Achieving a deep understanding of such systems necessitates generalizing “traditional” network theory, and the newfound deluge of data now makes it possible to test increasingly general frameworks for the study of networks. In particular, although adjacency matrices are useful to describe traditional single-layer networks, such a representation is insufficient for the analysis and description of multiplex and time-dependent networks. One must therefore develop a more general mathematical framework to cope with the challenges posed by multilayer complex systems. In this paper, we introduce a tensorial framework to study multilayer networks, and we discuss the generalization of several important network descriptors and dynamical processes—including degree centrality, clustering coefficients, eigenvector centrality, modularity, von Neumann entropy, and diffusion—for this framework. We examine the impact of different choices in constructing these generalizations, and we illustrate how to obtain known results for the special cases of single-layer and multiplex networks. Our tensorial approach will be helpful for tackling pressing problems in multilayer complex systems, such as inferring who is influencing whom (and by which media) in multichannel social networks and developing routing techniques for multimodal transportation systems.
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A novel multilayer model with controllable mechanical properties for magnesium-based bone plates.
Zhou, Juncen; Huang, Wanru; Li, Qing; She, Zuxin; Chen, Funan; Li, Longqin
2015-04-01
Proper mechanical properties are essential for the clinical application of magnesium-based implants. In the present work, a novel multilayer model composed of three layers with desirable features was developed. The modulus of the multilayer model can be adjusted by changing the thickness of each layer. To combine three layers and improve the corrosion resistance of the whole multilayer model, the polycaprolactone coating was employed. In the immersion test, pH values, the concentration of released magnesium ions, and weight loss indicate that the corrosion rate of multilayer models is considerable lower than that of the one-layer bare substrate. The three-point bending test, which is used to examine models' mechanical properties, shows that the flexural modulus of multilayer models is reduced effectively. In addition, the mechanical degradation of multilayer models is more stable, compared to the one-layer substrate.
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The NSLS-II Multilayer Laue Lens Deposition System
International Nuclear Information System (INIS)
Conley, R.; Bouet, N.; Biancarosa, J.; Shen, Q.; Boas, L.; Feraca, J.; Rosenbaum, L.
2009-01-01
The NSLS-II(1) program has a requirement for an unprecedented level of x-ray nanofocusing and has selected the wedged multilayer Laue lens(2,3) (MLL) as the optic of choice to meet this goal. In order to fabricate the MLL a deposition system is required that is capable of depositing depth-graded and laterally-graded multilayers with precise thickness control over many thousands of layers, with total film growth in one run up to 100 m thick or greater. This machine design expounds on the positive features of a rotary deposition system(4) constructed previously for MLLs and will contain multiple stationary, horizontally-oriented magnetron sources where a transport will move a substrate back and forth in a linear fashion over shaped apertures at well-defined velocities to affect a multilayer coating.
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Electron with arbitrary pseudo-spins in multilayer graphene
Institute of Scientific and Technical Information of China (English)
Worasak Prarokijjak; Bumned Soodchomshom
2015-01-01
Using the low-energy effective Hamiltonian of the ABC-stacked multilayer graphene, the pseudo-spin coupling to real orbital angular momentum of electrons in multilayer graphene is investigated. We show that the electron wave function in N-layer graphene mimics the behavior of a particle with a spin of N × (}/2), where N={1, 2, 3, . . .}. It is said that for N>1 the low-energy effective Hamiltonian for ABC-stacked graphene cannot be used to describe pseudo-spin-1/2 particles. The wave function of electrons in multilayer graphene may behave like fermionic (or bosonic) particle for N being odd (or even). In this paper, we propose a theory of graphene serving as a host material of electrons with arbitrary pseudo-spins tunable by changing the number of graphene layers.
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Electron with arbitrary pseudo-spins in multilayer graphene
International Nuclear Information System (INIS)
Prarokijjak Worasak; Soodchomshom Bumned
2015-01-01
Using the low-energy effective Hamiltonian of the ABC-stacked multilayer graphene, the pseudo-spin coupling to real orbital angular momentum of electrons in multilayer graphene is investigated. We show that the electron wave function in N-layer graphene mimics the behavior of a particle with a spin of N × (ħ/2), where N = {1, 2, 3,…}. It is said that for N > 1 the low-energy effective Hamiltonian for ABC-stacked graphene cannot be used to describe pseudo-spin-1/2 particles. The wave function of electrons in multilayer graphene may behave like fermionic (or bosonic) particle for N being odd (or even). In this paper, we propose a theory of graphene serving as a host material of electrons with arbitrary pseudo-spins tunable by changing the number of graphene layers. (paper)
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Multilayer network decoding versatility and trust
Sarkar, Camellia; Yadav, Alok; Jalan, Sarika
2016-01-01
In the recent years, the multilayer networks have increasingly been realized as a more realistic framework to understand emergent physical phenomena in complex real-world systems. We analyze massive time-varying social data drawn from the largest film industry of the world under a multilayer network framework. The framework enables us to evaluate the versatility of actors, which turns out to be an intrinsic property of lead actors. Versatility in dimers suggests that working with different types of nodes are more beneficial than with similar ones. However, the triangles yield a different relation between type of co-actor and the success of lead nodes indicating the importance of higher-order motifs in understanding the properties of the underlying system. Furthermore, despite the degree-degree correlations of entire networks being neutral, multilayering picks up different values of correlation indicating positive connotations like trust, in the recent years. The analysis of weak ties of the industry uncovers nodes from a lower-degree regime being important in linking Bollywood clusters. The framework and the tools used herein may be used for unraveling the complexity of other real-world systems.
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Investigation of aperiodic W/C multi-layer mirror for X-ray optics
International Nuclear Information System (INIS)
Wang Zhanshan; Cheng Xinbin; Zhu Jingtao; Huang Qiushi; Zhang Zhong; Chen Lingyan
2011-01-01
Design, fabrication and characterization of aperiodic tungsten/carbon (W/C) multi-layer mirror were studied. W/C multi-layer was designed as a broad-angle reflective supermirror for Cu-Kα line (λ = 0.154 nm) in the grazing incident angular range (0.9-1.1 deg.) using simulated annealing algorithm. To deposit the W/C depth-graded multi-layer mirror accurately, we introduce an effective layer growth rate as a function of layer thickness. This method greatly improves the reflectivity curve compared to the conventional multi-layer mirror prepared with constant growth rate. The deposited multi-layer mirror exhibits an average reflectivity of 19% over the grazing incident angle range of 0.88-1.08 deg. which mainly coincides with the designed value. Furthermore, the physical mechanisms were discussed and the re-sputtering process of light-atom layers is accounted for the modification of layer thicknesses which leads to the effective growth rates. Using this calibration method, the aperiodic multi-layer mirrors can be better fabricated for X-ray optics.
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Measure of Node Similarity in Multilayer Networks
DEFF Research Database (Denmark)
Møllgaard, Anders; Zettler, Ingo; Dammeyer, Jesper
2016-01-01
university.Our analysis is based on data obtained using smartphones equipped with customdata collection software, complemented by questionnaire-based data. The networkof social contacts is represented as a weighted multilayer network constructedfrom different channels of telecommunication as well as data...... might bepresent in one layer of the multilayer network and simultaneously be absent inthe other layers. For a variable such as gender, our measure reveals atransition from similarity between nodes connected with links of relatively lowweight to dis-similarity for the nodes connected by the strongest...
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Exchange interactions in Fe/Y multilayers
International Nuclear Information System (INIS)
Elkabil, R.; Elkaidi, I.; Annouar, F.; Lassri, H.; Hamdoun, A.; Bensassi, B.; Berrada, A.; Krishnan, R.
2005-01-01
The magnetization of Fe/Y multilayers has been measured as a function of temperature. A bulk-like T 3/2 temperature dependence of the magnetization is observed for all multilayers in the temperature range 5-300 K. The spin-wave constant B is found to decrease inversely with t Fe . A simple theoretical model with exchange interactions only, and with non-interacting magnons, has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction J b , surface exchange interaction J s and the interlayer exchange interaction J I for various Fe layer thicknesses have been obtained
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Energy Technology Data Exchange (ETDEWEB)
Canto, C.E., E-mail: carloscanto2012@yahoo.com.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Andrade, E.; Lucio, O. de; Cruz, J.; Solís, C. [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 México D.F. (Mexico); Rocha, M.F. [ESIME-Z, IPN, U.P. ALM, Gustavo A. Madero, C.P. 07738 México D.F. (Mexico); Alemón, B. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jalisco 45101 (Mexico); Tecnológico de Monterrey, Av. General Ramón Corona 2514, Col. Nuevo México, Zapopan, Jalisco 45201 (Mexico); Flores, M. [Departamento de Ingeniería de Proyectos, CUCEI, Universidad de Guadalajara, J. Guadalupe Zuno 48, Los Belenes, Zapopan, Jalisco 45101 (Mexico); Huegel, J.C. [Tecnológico de Monterrey, Av. General Ramón Corona 2514, Col. Nuevo México, Zapopan, Jalisco 45201 (Mexico)
2016-03-15
The corrosion resistance and the elemental profile of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by Physical Vapor Deposition (PVD) reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt to enhance the corrosion resistance of a biomedical alloy of CoCrMo. Corrosion tests were performed using Simulated Body Fluid (SBF) using potentiodynamic polarization tests at typical body temperature. The elemental composition and thickness of the coatings were evaluated with the combination of two ion beam analysis (IBA) techniques: a Rutherford Backscattering Spectroscopy (RBS) with alpha beam and a Nuclear Reaction Analysis with a deuteron beam.
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International Nuclear Information System (INIS)
Canto, C.E.; Andrade, E.; Lucio, O. de; Cruz, J.; Solís, C.; Rocha, M.F.; Alemón, B.; Flores, M.; Huegel, J.C.
2016-01-01
The corrosion resistance and the elemental profile of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by Physical Vapor Deposition (PVD) reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt to enhance the corrosion resistance of a biomedical alloy of CoCrMo. Corrosion tests were performed using Simulated Body Fluid (SBF) using potentiodynamic polarization tests at typical body temperature. The elemental composition and thickness of the coatings were evaluated with the combination of two ion beam analysis (IBA) techniques: a Rutherford Backscattering Spectroscopy (RBS) with alpha beam and a Nuclear Reaction Analysis with a deuteron beam.
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Domain structures and magnetization reversal in Co/Pd and CoFeB/Pd multilayers
Energy Technology Data Exchange (ETDEWEB)
Sbiaa, R., E-mail: rachid@squ.edu.om [Department of Physics, Sultan Qaboos University, P.O. Box 36, PC 123 (Oman); Ranjbar, M. [Physics Department, University of Gothenburg, 412 96 Gothenburg (Sweden); Åkerman, J. [Physics Department, University of Gothenburg, 412 96 Gothenburg (Sweden); Materials Physics, School of ICT, Royal Institute of Technology (KTH), 164 40 Kista (Sweden)
2015-05-07
Domain structures and magnetization reversal of (Co/Pd) and (CoFeB/Pd) multilayers with 7 and 14 repeats were investigated. The Co-based multilayers show much larger coercivities, a better squareness, and a sharper magnetization switching than CoFeB-based multilayers. From magnetic force microscopy observations, both structures show strong reduction in domains size as the number of repeats increases but the magnetic domains for Co-based multilayers are more than one order of magnitude larger than for CoFeB-based multilayers. By imaging domains at different times, breaks in the (CoFeB/Pd) multilayer stripes were observed within only few hours, while no change could be seen for (Co/Pd) multilayers. Although CoFeB single layers are suitable for magnetoresistive devices due to their large spin polarization and low damping constants, their lamination with Pd suffers mainly from thermal instability.
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The Paramagnetism of Small Amounts of Mn Dissolved in Cu-Al and Cu-Ge Alloys
Energy Technology Data Exchange (ETDEWEB)
Myers, H P; Westin, R
1963-06-15
Previous measurements of the valency of Mn in Cu-Zn alloys have been confirmed by measurements with the isoelectronic Cu-Al and Cu-Ge alloys as matrices for Mn. The valency, having the value i in pure copper, decreases slightly with increasing electron to atom ratio attaining the values 0. 9 and 0. 8 at the limiting composition in the Al and Ge alloys respectively. The apparent size of Mn in these alloys is discussed.
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The Paramagnetism of Small Amounts of Mn Dissolved in Cu-Al and Cu-Ge Alloys
International Nuclear Information System (INIS)
Myers, H.P.; Westin, R.
1963-06-01
Previous measurements of the valency of Mn in Cu-Zn alloys have been confirmed by measurements with the isoelectronic Cu-Al and Cu-Ge alloys as matrices for Mn. The valency, having the value i in pure copper, decreases slightly with increasing electron to atom ratio attaining the values 0. 9 and 0. 8 at the limiting composition in the Al and Ge alloys respectively. The apparent size of Mn in these alloys is discussed
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Finite-width plasmonic waveguides with hyperbolic multilayer cladding
DEFF Research Database (Denmark)
Babicheva, Viktoriia; Shalaginov, Mikhail Y.; Ishii, Satoshi
2015-01-01
Engineering plasmonic metamaterials with anisotropic optical dispersion enables us to tailor the properties of metamaterial-based waveguides. We investigate plasmonic waveguides with dielectric cores and multilayer metal-dielectric claddings with hyperbolic dispersion. Without using any homogeniz......Engineering plasmonic metamaterials with anisotropic optical dispersion enables us to tailor the properties of metamaterial-based waveguides. We investigate plasmonic waveguides with dielectric cores and multilayer metal-dielectric claddings with hyperbolic dispersion. Without using any...
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Docetaxel-loaded multilayer nanoparticles with nanodroplets for cancer therapy
Directory of Open Access Journals (Sweden)
Oh KS
2016-03-01
Full Text Available Keun Sang Oh,1,* Kyungim Kim,1,* Byeong Deok Yoon,1 Hye Jin Lee,1 Dal Yong Park,1 Eun-yeong Kim,1 Kiho Lee,1 Jae Hong Seo,2 Soon Hong Yuk1,2 1College of Pharmacy, Korea University, Sejong, 2Biomedical Research Center, Korea University Guro Hospital, Guro-gu, Seoul, Republic of Korea *These authors contributed equally to this work Abstract: A mixture of docetaxel (DTX and Solutol® HS 15 (Solutol transiently formed nanodroplets when it was suspended in an aqueous medium. However, nanodroplets that comprised DTX and Solutol showed a rapid precipitation of DTX because of their unstable characteristics in the aqueous medium. The incorporation of nanodroplets that comprised DTX and Solutol through vesicle fusion and subsequent stabilization was designed to prepare multilayer nanoparticles (NPs with a DTX-loaded Solutol nanodroplet (as template NPs core for an efficient delivery of DTX as a chemotherapeutic drug. As a result, the DTX-loaded Solutol nanodroplets (~11.7 nm were observed to have an increased average diameter (from 11.7 nm to 156.1 nm and a good stability of the hydrated NPs without precipitation of DTX by vesicle fusion and multilayered structure, respectively. Also, a long circulation of the multilayer NPs was observed, and this was due to the presence of Pluronic F-68 on the surface of the multilayer NPs. This led to an improved antitumor efficacy based on the enhanced permeation and retention effect. Therefore, this study indicated that the multilayer NPs have a considerable potential as a drug delivery system with an enhanced therapeutic efficacy by blood circulation and with low side effects. Keywords: multilayer nanoparticles, Solutol, Pluronic F-68, docetaxel, cancer therapy
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Multilayer mirrors as power filters in insertion device beamlines
International Nuclear Information System (INIS)
Kortright, J.B.; DiGennaro, R.S.
1988-08-01
The power-filtering capabilities of multilayer band-pass x-ray mirrors relative to total reflection low-pass mirrors is presented. Results are based on calculations assuming proposed wiggler sources on the upcoming generation of low energy (1.5 GeV) and high energy (7.0 GeV) synchrotron radiation sources. Results show that multilayers out-perform total reflection mirrors in terms of reduction in reflected power by roughly an order of magnitude, with relatively small increases in total absorbed power and power density over total reflection mirrors, and with comparable reflected flux values. Various aspects of this potential application of multilayer x-ray optics are discussed. 13 refs., 3 figs., 1 tab
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Anomalously Weak Scattering in Metal-Semiconductor Multilayer Hyperbolic Metamaterials
Directory of Open Access Journals (Sweden)
Hao Shen
2015-05-01
Full Text Available In contrast to strong plasmonic scattering from metal particles or structures in metal films, we show that patterns of arbitrary shape fabricated out of multilayer hyperbolic metamaterials become invisible within a chosen band of optical frequencies. This is due to anomalously weak scattering when the in-plane permittivity of the multilayer hyperbolic metamaterials is tuned to match with the surrounding medium. This new phenomenon is described theoretically and demonstrated experimentally by optical characterization of various patterns in Au-Si multilayer hyperbolic metamaterials. This anomalously weak scattering is insensitive to pattern sizes, shapes, and incident angles, and has potential applications in scattering cross-section engineering, optical encryption, low-observable conductive probes, and optoelectric devices.
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Tunable Multilayer Graphene Metamaterials for Terahertz/Infrared Waveguide Modulators
DEFF Research Database (Denmark)
Khromova, Irina; Andryieuski, Andrei; Lavrinenko, Andrei
regimes of multilayer graphene-dielectric artificial metamaterials. The interplay between interband and intraband transitions in graphene allows converting the structure into a transparent and/or electromagnetically dense artificial medium. The gate voltage can be used to electrically control...... the concentration of carriers in the graphene sheets and, thus, efficiently change the dispersion of the whole structure. Placed inside a hollow waveguide, a multilayer graphene/dielectric metamaterial provides high-speed modulation and tunable bandpass filtering. The absence of scattered radiation enables dense...... the latter to shift its central frequency by 1:25% per every meV graphene Fermi energy change. We believe that graphene-dielectric multilayer metamaterials will constitute the functional platform for THz-IR waveguide-integrated devices....
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Multilayer composite material and method for evaporative cooling
Buckley, Theresa M. (Inventor)
2002-01-01
A multilayer composite material and method for evaporative cooling of a person employs an evaporative cooling liquid that changes phase from a liquid to a gaseous state to absorb thermal energy. The evaporative cooling liquid is absorbed into a superabsorbent material enclosed within the multilayer composite material. The multilayer composite material has a high percentage of the evaporative cooling liquid in the matrix. The cooling effect can be sustained for an extended period of time because of the high percentage of phase change liquid that can be absorbed into the superabsorbent. Such a composite can be used for cooling febrile patients by evaporative cooling as the evaporative cooling liquid in the matrix changes from a liquid to a gaseous state to absorb thermal energy. The composite can be made with a perforated barrier material around the outside to regulate the evaporation rate of the phase change liquid. Alternatively, the composite can be made with an imperveous barrier material or semipermeable membrane on one side to prevent the liquid from contacting the person's skin. The evaporative cooling liquid in the matrix can be recharged by soaking the material in the liquid. The multilayer composite material can be fashioned into blankets, garments and other articles.
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Multilayer tape cast SOFC – Effect of anode sintering temperature
DEFF Research Database (Denmark)
Hauch, Anne; Birkl, Christoph; Brodersen, Karen
2012-01-01
Multilayer tape casting (MTC) is considered a promising, cost-efficient, up-scalable shaping process for production of planar anode supported solid oxide fuel cells (SOFC). Multilayer tape casting of the three layers comprising the half cell (anode support/active anode/electrolyte) can potentially...
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Boundary element method in dynamic interaction of structures with multilayers media
International Nuclear Information System (INIS)
Mihalache, N.; Poterasu, V.F.
1993-01-01
The paper presents the problems of dynamic interaction between the multilayers media and structure by means of B.E.M., using Green's functions. The structure considered by the authors as a particular problem concerns a reinforced concrete shear wall and soil foundation of three layers having different thickness and mechanical characteristics. The authors will present comparatively the stresses and the displacements in static and dynamic regime interaction response of the structure. Theoretical part of the paper presents: Green's functions for the multilayers media in dynamic regime, stiffness matrices, stresses and displacements in the multilayers media exprimed by means of the Green's functions induced by the shear and horizontal forces, computer program, consideration for dynamic, structure-foundation-multilayers soil foundation interaction. (author)
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Dallera, C.; de Michelis, B.; Puppin, E.; Braicovich, L.; Brookes, N. B.
1996-01-01
The electronic states of the θ' phase formed by thermal aging in the Al-Cu (0.5 at. %) alloy are compared with those in C16-CuAl2, which is the final phase separated at equilibrium. This is done by means of Cu Lα fluorescence spectroscopy. The high brilliance of undulator radiation used as an excitation source is exploited. The spectra are taken using the first harmonic of the undulator at 1.7 keV, with a full width half maximum of ~250 eV. A narrowing of around 0.5 eV of the Cu Lα spectra in the θ' phase is found. This is explained in terms of the differences in the Cu 3d-Cu 3d interaction in the two phases and of the hybridization between Cu 3d and the nearly free-electron-like electrons. The results demonstrate the future possibilities of fluorescence spectroscopy of minority species in inhomogeneous systems.
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Penfold, Jeffrey; Thomas, Robert K; Li, Peixun; Xu, Hui; Tucker, Ian M; Petkov, Jordan T; Sivia, Devinderjit S
2015-06-23
Surface multilayer formation from the anionic-nonionic surfactant mixture of sodium dodecyl dioxyethylene sulfate, SLES, and monododecyl dodecaethylene glycol, C12E12, by the addition of multivalent Al(3+) counterions at the solid-solution interface is observed and characterized by neutron reflectivity, NR. The ability to form surface multilayer structures on hydrophobic and hydrophilic silica and cellulose surfaces is demonstrated. The surface multilayer formation is more pronounced and more well developed on the hydrophilic and hydrophobic silica surfaces than on the hydrophilic and hydrophobic cellulose surfaces. The less well developed multilayer formation on the cellulose surfaces is attributed to the greater surface inhomogeneities of the cellulose surface which partially inhibit lateral coherence and growth of the multilayer domains at the surface. The surface multilayer formation is associated with extreme wetting properties and offers the potential for the manipulation of the solid surfaces for enhanced adsorption and control of the wetting behavior.
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Domain wall theory and exchange stiffness in Co/Pd multilayers
Kambersky, V.; Kambersky, V.; de Haan, P.; Simsova, J.; Porthun, S.; Porthun, S.; Gemperle, R.; Lodder, J.C.
1996-01-01
The stripe model of domain structure in multilayers is studied by micromagnetic simulation. The results indicate a strong reduction of the effective domain wall energy (by dipolar effects). Domain width measurements on sputtered Co/Pd multilayers are compared with the theory. The estimated exchange
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Durable Corrosion Resistance of Copper Due to Multi-Layer Graphene
Directory of Open Access Journals (Sweden)
Abhishek Tiwari
2017-09-01
Full Text Available Ultra-thin graphene coating has been reported to provide considerable resistance against corrosion during short-term exposures, however, there is great variability in the corrosion resistance due to graphene coating in different studies. It may be possible to overcome the problem of hampered corrosion protection ability of graphene that is caused due to defective single layer graphene by applying multilayer graphene. Systematic electrochemical characterization showed that the multilayer graphene coating developed in the study provided significant corrosion resistance in a chloride solution and the corrosion resistance was sustained for long durations (~400 h, which is attributed to the multilayer graphene.
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Characterization of multilayer nitride coatings by electron microscopy and modulus mapping
International Nuclear Information System (INIS)
Pemmasani, Sai Pramod; Rajulapati, Koteswararao V.; Ramakrishna, M.; Valleti, Krishna; Gundakaram, Ravi C.; Joshi, Shrikant V.
2013-01-01
This paper discusses multi-scale characterization of physical vapour deposited multilayer nitride coatings using a combination of electron microscopy and modulus mapping. Multilayer coatings with a triple layer structure based on TiAlN and nanocomposite nitrides with a nano-multilayered architecture were deposited by Cathodic arc deposition and detailed microstructural studies were carried out employing Energy Dispersive Spectroscopy, Electron Backscattered Diffraction, Focused Ion Beam and Cross sectional Transmission Electron Microscopy in order to identify the different phases and to study microstructural features of the various layers formed as a result of the deposition process. Modulus mapping was also performed to study the effect of varying composition on the moduli of the nano-multilayers within the triple layer coating by using a Scanning Probe Microscopy based technique. To the best of our knowledge, this is the first attempt on modulus mapping of cathodic arc deposited nitride multilayer coatings. This work demonstrates the application of Scanning Probe Microscopy based modulus mapping and electron microscopy for the study of coating properties and their relation to composition and microstructure. - Highlights: • Microstructure of a triple layer nitride coating studied at multiple length scales. • Phases identified by EDS, EBSD and SAED (TEM). • Nanolayered, nanocomposite structure of the coating studied using FIB and TEM. • Modulus mapping identified moduli variation even in a nani-multilayer architecture
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Ring-dot-shaped multilayer piezoelectric step-down transformers using PZT-based ceramics
International Nuclear Information System (INIS)
Kim, Insung; Joo, Hyeonkyu; Song, Jaesung; Jeong, Soonjong; Kim, Minsoo
2010-01-01
In this study, multilayer piezo stack transformers for switching mode power supply (SMPS) application were manufactured using 0.01Pb(Ni 1/3 Nb 2/3 )O 3 - 0.08Pb(Mn 1/3 Nb 2/3 )O 3 - 0.91Pb(Zr 0.505 Ti 0.495 )O 3 (PNN-PMN-PZT) ceramics. The voltage ratio of a multilayer piezo stack transformer showed a maximum at the resonance frequency of the input and then increased with increasing load resistance. The efficiency of the multilayer piezo stack transformer showed its highest value at around the matching load. The output power increased with increasing input voltage. The temperature of the multilayer piezo stack transformer increased with increasing output power and load resistance. The manufactured multilayer piezo stack transformer could be used up to 5 W at a resonance frequency of 70.25 kHz for SMPS application because the temperature rise from room temperature is believed to about 20 .deg. C and because the transformer is electrically stable. The newly-developed ring-dot-type step-down multilayer piezo stack transformer shows possible applications as SMPS for electronic power sources with excellent input-to-output properties.
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High-reflectance La/B-based multilayer mirror for 6.x nm wavelength
Kuznetsov, Dmitry; Yakshin, Andrey; Sturm, Jacobus Marinus; van de Kruijs, Robbert Wilhelmus Elisabeth; Louis, Eric; Bijkerk, Frederik
2015-01-01
We report a hybrid thin-film deposition procedure to significantly enhance the reflectivity of La/B-based multilayer structures. This is of relevance for applications of multilayer optics at 6.7-nm wavelength and beyond. Such multilayers showed a reflectance of 64.1% at 6.65 nm measured at
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Energy Technology Data Exchange (ETDEWEB)
Cai Kaiyong, E-mail: Kaiyong_cai@cqu.edu.cn [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Sui Xiaojing; Hu Yan [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China); Zhao Li [China National Centre for Biotechnology Development, No. 16, Xi Si Huan Zhong Lu, Haidian District, Beijing 100036 (China); Lai Min; Luo Zhong; Liu Peng; Yang Weihu [Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, College of Bioengineering, Chongqing University, Chongqing 400044 (China)
2011-12-01
To improve the corrosion resistance of magnesium alloy, we reported a novel approach for the fabrication of anticorrosive multilayers onto AZ91D substrates. The multilayers were composed of poly(ethylene imine) (PEI), poly(styrene sulfonate) (PSS) and 8-hydroxyquinoline (8HQ). They were deposited onto AZ91D substrates via a spin-assisted layer-by-layer (LbL) technique. The multilayered structure was stabilized with glutaraldehyde (GA) as crossing linker. It was confirmed by Fourier transform infrared spectroscopy (FT-IR). Surface morphologies and elemental compositions of the formed anticorrosive multilayers were characterized with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The corrosion performance of the multilayer coated AZ91D substrates was characterized by hydrogen evolution. The results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements suggested that the multilayered coating improved the corrosion resistance of AZ91D substrates. In vitro study revealed that the multilayered coating was cytocompatible. The study provides a potential alternative for the fabrication of corrosion resistant magnesium alloy-based implants. Highlights: {yields} Corrosion protective multilayers have been constructed onto AZ91D substrates via layer by layer technique. {yields} The multilayered structured containing 8-hydroxyquinoline highly improves the corrosion resistance of AZ91D substrates. {yields} The novel multilayered coating is potentially important for developing corrosion resistant magnesium alloy-based implants.
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International Nuclear Information System (INIS)
Cai Kaiyong; Sui Xiaojing; Hu Yan; Zhao Li; Lai Min; Luo Zhong; Liu Peng; Yang Weihu
2011-01-01
To improve the corrosion resistance of magnesium alloy, we reported a novel approach for the fabrication of anticorrosive multilayers onto AZ91D substrates. The multilayers were composed of poly(ethylene imine) (PEI), poly(styrene sulfonate) (PSS) and 8-hydroxyquinoline (8HQ). They were deposited onto AZ91D substrates via a spin-assisted layer-by-layer (LbL) technique. The multilayered structure was stabilized with glutaraldehyde (GA) as crossing linker. It was confirmed by Fourier transform infrared spectroscopy (FT-IR). Surface morphologies and elemental compositions of the formed anticorrosive multilayers were characterized with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The corrosion performance of the multilayer coated AZ91D substrates was characterized by hydrogen evolution. The results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements suggested that the multilayered coating improved the corrosion resistance of AZ91D substrates. In vitro study revealed that the multilayered coating was cytocompatible. The study provides a potential alternative for the fabrication of corrosion resistant magnesium alloy-based implants. Highlights: → Corrosion protective multilayers have been constructed onto AZ91D substrates via layer by layer technique. → The multilayered structured containing 8-hydroxyquinoline highly improves the corrosion resistance of AZ91D substrates. → The novel multilayered coating is potentially important for developing corrosion resistant magnesium alloy-based implants.
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Investigation of CoFeV/TiZr multilayer by polarized neutron reflectometry
International Nuclear Information System (INIS)
Chen Bo; Li Xinxi; Huang Chaoqiang
2007-06-01
The interracial structures of CoFeV/TiZr multilayer play an important role in performance of polarizing supermirrors. Aiming to requirement, CoFeV/ TiZr layered samples with different structures were prepared. Specular reflection of polarized neutrons was employed to study the depth profile of scattering length, density, thickness and roughness of CoFeV/TiZr multilayer and magnetically dead layers. The result shows that the roughness in CoFeV/ TiZr multilayer can be described with roughness increase law and the thickness of magnetically dead layers is about 0.5 nm. The producing technology of the multilayer reaches the requirements. (authors)
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Degradation of periodic multilayers as seen by small-angle x-ray scattering and x-ray diffraction
Rafaja, D; Simek, D; Zdeborova, L; Valvoda, V
2002-01-01
The capabilities of small-angle x-ray scattering (SAXS) and wide-angle x-ray diffraction (XRD) to recognize structural changes in periodic multilayers were compared on Fe/Au multilayers with different degrees of structural degradation. Experimental results have shown that both methods are equally sensitive to the multilayer degradation, i.e., to the occurrence of non-continuous interfaces, to short-circuits in the multilayer structure and to the multilayer precipitation. XRD yielded additional information on the multilayer crystallinity, whilst SAXS could better recognize fragments of a long-range periodicity (remnants of the original multilayer structure). Changes in the multilayer structure were initiated by successive annealing at 200 and 300 deg. C. Experimental data were complemented by numerical simulations performed using a combination of optical theory and the distorted wave Born approximation for SAXS or the kinematical Born approximation for XRD.
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Multilayer DNA Origami Packed on Hexagonal and Hybrid Lattices
DEFF Research Database (Denmark)
Ke, Yonggang; Voigt, Niels Vinther; Shih, William M.
2012-01-01
“Scaffolded DNA origami” has been proven to be a powerful and efficient approach to construct two-dimensional or three-dimensional objects with great complexity. Multilayer DNA origami has been demonstrated with helices packing along either honeycomb-lattice geometry or square-lattice geometry....... Here we report successful folding of multilayer DNA origami with helices arranged on a close-packed hexagonal lattice. This arrangement yields a higher density of helical packing and therefore higher resolution of spatial addressing than has been shown previously. We also demonstrate hybrid multilayer...... DNA origami with honeycomb-lattice, square-lattice, and hexagonal-lattice packing of helices all in one design. The availability of hexagonal close-packing of helices extends our ability to build complex structures using DNA nanotechnology....
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Multilayer DNA origami packed on hexagonal and hybrid lattices.
Ke, Yonggang; Voigt, Niels V; Gothelf, Kurt V; Shih, William M
2012-01-25
"Scaffolded DNA origami" has been proven to be a powerful and efficient approach to construct two-dimensional or three-dimensional objects with great complexity. Multilayer DNA origami has been demonstrated with helices packing along either honeycomb-lattice geometry or square-lattice geometry. Here we report successful folding of multilayer DNA origami with helices arranged on a close-packed hexagonal lattice. This arrangement yields a higher density of helical packing and therefore higher resolution of spatial addressing than has been shown previously. We also demonstrate hybrid multilayer DNA origami with honeycomb-lattice, square-lattice, and hexagonal-lattice packing of helices all in one design. The availability of hexagonal close-packing of helices extends our ability to build complex structures using DNA nanotechnology. © 2011 American Chemical Society
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Multilayer modal actuator-based piezoelectric transformers.
Huang, Yao-Tien; Wu, Wen-Jong; Wang, Yen-Chieh; Lee, Chih-Kung
2007-02-01
An innovative, multilayer piezoelectric transformer equipped with a full modal filtering input electrode is reported herein. This modal-shaped electrode, based on the orthogonal property of structural vibration modes, is characterized by full modal filtering to ensure that only the desired vibration mode is excited during operation. The newly developed piezoelectric transformer is comprised of three layers: a multilayered input layer, an insulation layer, and a single output layer. The electrode shape of the input layer is derived from its structural vibration modal shape, which takes advantage of the orthogonal property of the vibration modes to achieve a full modal filtering effect. The insulation layer possesses two functions: first, to couple the mechanical vibration energy between the input and output, and second, to provide electrical insulation between the two layers. To meet the two functions, a low temperature, co-fired ceramic (LTCC) was used to provide the high mechanical rigidity and high electrical insulation. It can be shown that this newly developed piezoelectric transformer has the advantage of possessing a more efficient energy transfer and a wider optimal working frequency range when compared to traditional piezoelectric transformers. A multilayer piezoelectric, transformer-based inverter applicable for use in LCD monitors or portable displays is presented as well.
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Multilayer Relaxation and Surface Energies of Metallic Surfaces
Bozzolo, Guillermo; Rodriguez, Agustin M.; Ferrante, John
1994-01-01
The perpendicular and parallel multilayer relaxations of fcc (210) surfaces are studied using equivalent crystal theory (ECT). A comparison with experimental and theoretical results is made for AI(210). The effect of uncertainties in the input parameters on the magnitudes and ordering of surface relaxations for this semiempirical method is estimated. A new measure of surface roughness is proposed. Predictions for the multilayer relaxations and surface energies of the (210) face of Cu and Ni are also included.
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Anisotropic in-plane thermal conductivity in multilayer silicene
Zhou, Yang; Guo, Zhi-Xin; Chen, Shi-You; Xiang, Hong-Jun; Gong, Xin-Gao
2018-06-01
We systematically study thermal conductivity of multilayer silicene by means of Boltzmann Transportation Equation (BTE) method. We find that their thermal conductivity strongly depends on the surface structures. Thermal conductivity of bilayer silicene varies from 3.31 W/mK to 57.9 W/mK with different surface structures. Also, the 2 × 1 surface reconstruction induces unusual large thermal conductivity anisotropy, which reaches 70% in a four-layer silicene. We also find that the anisotropy decreases with silicene thickness increasing, owing to the significant reduction of thermal conductivity in the zigzag direction and its slight increment in the armchair direction. Finally, we find that both the phonon-lifetime anisotropy and the phonon-group-velocity anisotropy contribute to the thermal conductivity anisotropy of multilayer silicene. These findings could be helpful in the field of heat management, thermoelectric applications involving silicene and other multilayer nanomaterials with surface reconstructions in the future.
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Optimisation of multi-layer rotationally moulded foamed structures
Pritchard, A. J.; McCourt, M. P.; Kearns, M. P.; Martin, P. J.; Cunningham, E.
2018-05-01
Multi-layer skin-foam and skin-foam-skin sandwich constructions are of increasing interest in the rotational moulding process for two reasons. Firstly, multi-layer constructions can improve the thermal insulation properties of a part. Secondly, foamed polyethylene sandwiched between solid polyethylene skins can increase the mechanical properties of rotationally moulded structural components, in particular increasing flexural properties and impact strength (IS). The processing of multiple layers of polyethylene and polyethylene foam presents unique challenges such as the control of chemical blowing agent decomposition temperature, and the optimisation of cooling rates to prevent destruction of the foam core; therefore, precise temperature control is paramount to success. Long cooling cycle times are associated with the creation of multi-layer foam parts due to their insulative nature; consequently, often making the costs of production prohibitive. Devices such as Rotocooler®, a rapid internal mould water spray cooling system, have been shown to have the potential to significantly decrease cooling times in rotational moulding. It is essential to monitor and control such devices to minimise the warpage associated with the rapid cooling of a moulding from only one side. The work presented here demonstrates the use of threaded thermocouples to monitor the polymer melt in multi-layer sandwich constructions, in order to analyse the cooling cycle of multi-layer foamed structures. A series of polyethylene skin-foam test mouldings were produced, and the effect of cooling medium on foam characteristics, mechanical properties, and process cycle time were investigated. Cooling cycle time reductions of 45%, 26%, and 29% were found for increasing (1%, 2%, and 3%) chemical blowing agent (CBA) amount when using internal water cooling technology from ˜123°C compared with forced air cooling (FAC). Subsequently, a reduction of IS for the same skin-foam parts was found to be 1%, 4
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High proton conductivity in the molecular interlayer of a polymer nanosheet multilayer film.
Sato, Takuma; Hayasaka, Yuta; Mitsuishi, Masaya; Miyashita, Tokuji; Nagano, Shusaku; Matsui, Jun
2015-05-12
High proton conductivity was achieved in a polymer multilayer film with a well-defined two-dimensional lamella structure. The multilayer film was prepared by deposition of poly(N-dodecylacryamide-co-acrylic acid) (p(DDA/AA)) monolayers onto a solid substrate using the Langmuir-Blodgett technique. Grazing-angle incidence X-ray diffraction measurement of a 30-layer film of p(DDA/AA) showed strong diffraction peaks in the out-of-plane direction at 2θ = 2.26° and 4.50°, revealing that the multilayer film had a highly uniform layered structure with a monolayer thickness of 2.0 nm. The proton conductivity of the p(DDA/AA) multilayer film parallel to the layer plane direction was 0.051 S/cm at 60 °C and 98% relative humidity with a low activation energy of 0.35 eV, which is comparable to perfluorosulfonic acid membranes. The high conductivity and low activation energy resulted from the formation of uniform two-dimensional proton-conductive nanochannels in the hydrophilic regions of the multilayer film. The proton conductivity of the multilayer film perpendicular to the layer plane was determined to be 2.1 × 10(-13) S/cm. Therefore, the multilayer film showed large anisotropic conductivity with an anisotropic ratio of 2.4 × 10(11).
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Directory of Open Access Journals (Sweden)
Min-Chuan Wang
2016-11-01
Full Text Available The all-solid-state electrochromic device (ECD with the one substrate structure fabricated by the reactive dc magnetron sputtering (DCMS and cathodic vacuum arc plasma (CVAP technology has been developed for smart electrochromic (EC glass application. The EC layer and ion conductor layer were deposited by reactive DCMS and CVAP technology, respectively. The ion conductor layer Ta2O5 deposited by the CVAP technology has provided the better porous material structure for ion transportation and showed 1.76 times ion conductivity than devices with all sputtering process. At the same time, the EC layer WO3 and NiO deposited by the reactive DCMS have also provided the high quality and uniform characteristic to overcome the surface roughness effect of the CVAP ion conductor layer in multilayer device structure. The all-solid-state ECD with the CVAP ion conductor layer has demonstrated a maximum transmittance variation (ΔT of 55% at 550nm and a faster-switching speed. Furthermore, the lower equipment cost and higher deposition rate could be achieved by the application of CVAP technology.
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Energy Technology Data Exchange (ETDEWEB)
Agra, K.; Bohn, F. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Mori, T.J.A. [Laboratório Nacional de Luz Síncrotron, Rua Giuseppe Máximo Scolfaro, 1000, Guará, 13083-100 Campinas, SP (Brazil); Callegari, G.L.; Dorneles, L.S. [Departamento de Física, Universidade Federal de Santa Maria, 97105-900 Santa Maria, RS (Brazil); Correa, M.A., E-mail: marciocorrea@dfte.ufrn.br [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)
2016-12-15
We investigate the dynamic magnetic response though magnetoimpedance effect of ferromagnetic flexible NiFe/Ta and FeCuNbSiB/Ta multilayers under external stress. We explore the possibility of handling magnetic anisotropy, and consequently the magnetoimpedance effect, of magnetostrictive multilayers deposited onto flexible substrates. We quantify the sensitivity of the multilayers under external stress by calculating the ratio between impedance variations and external stress changes, and show that considerable values can be reached by tuning the magnetic field, frequency, magnetostriction constant, and external stress. The results extend possibilities of application of magnetostrictive multilayers deposited onto flexible substrates when under external stress and place them as very attractive candidates as element sensor for the development of sensitive smart touch sensors. - Highlights: • We investigate the magnetoimpedance effect in magnetostrictive flexible multilayers grown on flexible substrates. • The external applied stress enables to tuning the samples anisotropies, and consequently the MI performance. • The flexible substrate becomes promising candidate for RF-frequency devices.
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Electromechanical field effect transistors based on multilayer phosphorene nanoribbons
Energy Technology Data Exchange (ETDEWEB)
Jiang, Z.T., E-mail: jiangzhaotan@hotmail.com; Lv, Z.T.; Zhang, X.D.
2017-06-21
Based on the tight-binding Hamiltonian approach, we demonstrate that the electromechanical field effect transistors (FETs) can be realized by using the multilayer phosphorene nanoribbons (PNRs). The synergistic combination of the electric field and the external strains can establish the on–off switching since the electric field can shift or split the energy band, and the mechanical strains can widen or narrow the band widths. This kind of multilayer PNR FETs, much solider than the monolayer PNR one and more easily biased by different electric fields, has more transport channels consequently leading to the higher on–off current ratio or the higher sensitivity to the electric fields. Meanwhile, the strain-induced band-flattening will be beneficial for improving the flexibility in designing the electromechanical FETs. In addition, such electromechanical FETs can act as strain-controlled FETs or mechanical detectors for detecting the strains, indicating their potential applications in nano- and micro-electromechanical fields. - Highlights: • Electromechanical transistors are designed with multilayer phosphorene nanoribbons. • Electromechanical synergistic effect can establish the on–off switching more flexibly. • Multilayer transistors, solider and more easily biased, has more transport channels. • Electromechanical transistors can act as strain-controlled transistors or mechanical detectors.
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X-ray grazing incidence diffraction from multilayers
Energy Technology Data Exchange (ETDEWEB)
Tixier, S.; Boeni, P.; Swygenhoven, H. van; Horisberger, M. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1997-09-01
Grazing incidence scattering geometries using synchrotron radiation have been applied in order to characterise the roughness profiles and the structural coherence of multilayers. The lateral correlation length of the roughness profiles was evaluated using diffuse reflectivity in the `out of plane` geometry. This type of measurement is the only diffuse reflectivity technique allowing large lateral momentum transfer. It is typically suitable for correlation lengths smaller than 1000 A. The lateral structural coherence length of Ni{sub 3}Al/Ni multilayers as a function of the layer thickness was obtained by grazing incidence diffraction (GID). 3 figs., 1 ref.
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Electron transfer kinetics on mono- and multilayer graphene.
Velický, Matěj; Bradley, Dan F; Cooper, Adam J; Hill, Ernie W; Kinloch, Ian A; Mishchenko, Artem; Novoselov, Konstantin S; Patten, Hollie V; Toth, Peter S; Valota, Anna T; Worrall, Stephen D; Dryfe, Robert A W
2014-10-28
Understanding of the electrochemical properties of graphene, especially the electron transfer kinetics of a redox reaction between the graphene surface and a molecule, in comparison to graphite or other carbon-based materials, is essential for its potential in energy conversion and storage to be realized. Here we use voltammetric determination of the electron transfer rate for three redox mediators, ferricyanide, hexaammineruthenium, and hexachloroiridate (Fe(CN)(6)(3-), Ru(NH3)(6)(3+), and IrCl(6)(2-), respectively), to measure the reactivity of graphene samples prepared by mechanical exfoliation of natural graphite. Electron transfer rates are measured for varied number of graphene layers (1 to ca. 1000 layers) using microscopic droplets. The basal planes of mono- and multilayer graphene, supported on an insulating Si/SiO(2) substrate, exhibit significant electron transfer activity and changes in kinetics are observed for all three mediators. No significant trend in kinetics with flake thickness is discernible for each mediator; however, a large variation in kinetics is observed across the basal plane of the same flakes, indicating that local surface conditions affect the electrochemical performance. This is confirmed by in situ graphite exfoliation, which reveals significant deterioration of initially, near-reversible kinetics for Ru(NH3)(6)(3+) when comparing the atmosphere-aged and freshly exfoliated graphite surfaces.
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Preparation of multilayered nanocrystalline thin films with composition-modulated interfaces
International Nuclear Information System (INIS)
Biro, D.; Barna, P.B.; Szekely, L.; Geszti, O.; Hattori, T.; Devenyi, A.
2008-01-01
The properties of multilayer thin film structures depend on the morphology and structure of interfaces. A broad interface, in which the composition is varying, can enhance, e.g., the hardness of multilayer thin films. In the present experiments multilayers of TiAlN and CrN as well as TiAlN, CrN and MoS 2 were studied by using unbalanced magnetron sputter sources. The sputter sources were arranged side by side on an arc. This arrangement permits development of a transition zone between the layers, where the composition changes continuously. The multilayer system was deposited by one-fold oscillating movement of substrates in front of sputter sources. Thicknesses of layers could be changed both by oscillation frequency and by the power applied to sputter sources. Ti/Al: 50/50 at%, pure chromium and MoS 2 targets were used in the sputter sources. The depositions were performed in an Ar-N 2 mixture at 0.22 Pa working pressure. The sputtering power of the TiAl source was feed-back adjusted in fuzzy-logic mode in order to avoid fluctuation of the TiAl target sputter rate due to poisoning of the target surface. Structure characterization of films deposited on Si wafers covered by thermally grown SiO 2 was performed by cross-sectional transmission electron microscopy. At first a 100 nm thick Cr base layer was deposited on the substrate to improve adhesion, which was followed by a CrN transition layer. The CrN transition layer was followed by a 100 nm thick TiAlN/CrN multilayer system. The TiAlN/CrN/MoS 2 multilayer system was deposited on the surface of this underlayer system. The underlayer systems Cr, CrN and TiAlN/CrN were crystalline with columnar structure according to the morphology of zone T of the structure zone models. The column boundaries contained segregated phases showing up in the under-focused TEM images. The surface of the underlayer system was wavy due to dome-shaped columns. The nanometer-scaled TiAlN/CrN/MoS 2 multilayer system followed this waviness
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Ultra-short-period WC/SiC multilayer coatings for x-ray applications
International Nuclear Information System (INIS)
Fernández-Perea, Mónica; Pivovaroff, Mike J.; Soufli, Regina; Alameda, Jennifer; Mirkarimi, Paul; Descalle, Marie-Anne; Baker, Sherry L.; McCarville, Tom; Ziock, Klaus; Hornback, Donald; Romaine, Suzanne; Bruni, Ric; Zhong, Zhong; Honkimäki, Veijo; Ziegler, Eric; Christensen, Finn E.; Jakobsen, Anders C.
2013-01-01
Multilayer coatings enhance x-ray mirror performance at incidence angles steeper than the critical angle, allowing for improved flux, design flexibility and facilitating alignment. In an attempt to extend the use of multilayer coatings to photon energies higher than previously achieved, we have developed multilayers with ultra-short periods between 1 and 2 nm based on the material system WC/SiC. This material system was selected because it possesses very sharp and stable interfaces. In this article, we show highlights from a series of experiments performed in order to characterize the stress, microstructure and morphology of the multilayer films, as well as their reflective performance at photon energies from 8 to 384 keV
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Synchronous determination of mercury (II) and copper (II) based on quantum dots-multilayer film
International Nuclear Information System (INIS)
Ma Qiang; Ha Enna; Yang Fengping; Su Xingguang
2011-01-01
Graphical abstract: We developed a sensitive sensor for synchronous detection of Hg (II) and Cu (II) based on the quenchedand recovered PL intensity of QDs-multilayer films. Solutions containing Hg (II) or Cu (II) were used to quench the fluorescence of the QDs-multilayer films firstly. Then, glutathione (GSH) was used to remove Hg (II) or Cu (II) from the QDs-multilayer films due to stronger affinity of GSH-metal ions than that of QDs metal ions. Thus, the fluorescence of QDs-multilayer films was recovered. Highlights: → QDs-multilayer films were developed for synchronous detection of Hg (II) and Cu (II). → Hg (II) and Cu (II) could quench the photoluminescence of the QDs-multilayer films. → Glutathione was used to remove metal ions and recovery photoluminescence of QDs-multilayer films. - Abstract: A sensitive sensor for mercury (II) and copper (II) synchronous detection was established via the changed photoluminescence of CdTe quantum dots (QDs) multilayer films in this work. QDs were deposited on the quartz slides to form QDs-multilayer films by electrostatic interactions with poly(dimethyldiallyl ammonium chloride) (PDDA). Hg 2+ or Cu 2+ could quench the photoluminescence of the QDs-multilayer films, and glutathione (GSH) was used to remove Hg 2+ or Cu 2+ from QDs-multilayer films due to strong affinity of GSH-metal ions, which resulted in the recovered photoluminescence of QDs-multilayer films. There are good linear relationships between the metal ions concentration and the photoluminescence intensity of QDs in the quenched and recovered process. It was found that the Stern-Volmer constants for Hg 2+ are higher than that for Cu 2+ . Based on different quenching and recovery constant between Hg 2+ and Cu 2+ , the synchronous detection of Hg 2+ and Cu 2+ can be achieved. The linear ranges of this assay were obtained from 0.005 to 0.5 μM for Hg 2+ and from 0.01 to 1 μM for Cu 2+ , respectively. And the artificial water samples were determined by this
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Near-field heat transfer between graphene/hBN multilayers
Zhao, Bo; Guizal, Brahim; Zhang, Zhuomin M.; Fan, Shanhui; Antezza, Mauro
2017-06-01
We study the radiative heat transfer between multilayer structures made by a periodic repetition of a graphene sheet and a hexagonal boron nitride (hBN) slab. Surface plasmons in a monolayer graphene can couple with hyperbolic phonon polaritons in a single hBN film to form hybrid polaritons that can assist photon tunneling. For periodic multilayer graphene/hBN structures, the stacked metallic/dielectric array can give rise to a further effective hyperbolic behavior, in addition to the intrinsic natural hyperbolic behavior of hBN. The effective hyperbolicity can enable more hyperbolic polaritons that enhance the photon tunneling and hence the near-field heat transfer. However, the hybrid polaritons on the surface, i.e., surface plasmon-phonon polaritons, dominate the near-field heat transfer between multilayer structures when the topmost layer is graphene. The effective hyperbolic regions can be well predicted by the effective medium theory (EMT), thought EMT fails to capture the hybrid surface polaritons and results in a heat transfer rate much lower compared to the exact calculation. The chemical potential of the graphene sheets can be tuned through electrical gating and results in an additional modulation of the heat transfer. We found that the near-field heat transfer between multilayer structures does not increase monotonously with the number of layers in the stack, which provides a way to control the heat transfer rate by the number of graphene layers in the multilayer structure. The results may benefit the applications of near-field energy harvesting and radiative cooling based on hybrid polaritons in two-dimensional materials.
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A multilayer approach for turbidity currents
Fernandez-Nieto, Enrique; Castro Díaz, Manuel J.; Morales de Luna, Tomás
2017-04-01
When a river that carries sediment in suspension enters into a lake or the ocean it can form a plume that can be classified as hyperpycnal or hypopycnal. Hypopycnal plumes occurs if the combined density of the sediment and interstitial fluid is lower than that of the ambient. Hyperpycnal plumes are a class of sediment-laden gravity current commonly referred to as turbidity currents [7,9]. Some layer-averaged models have been previously developed (see [3, 4, 8] among others). Although this layer-averaged approach gives a fast and valuable information, it has the disadvantage that the vertical distribution of the sediment in suspension is lost. A recent technique based on a multilayer approach [1, 2, 6] has shown to be specially useful to generalize shallow water type models in order to keep track of the vertical components of the averaged variables in the classical shallow water equations. In [5] multilayer model is obtained using a vertical discontinuous Galerkin approach for which the vertical velocity is supposed to be piecewise linear and the horizontal velocity is supposed to be piecewise constant. In this work the technique introduced in [5] is generalized to derive a model for turbidity currents. This model allows to simulate hyperpycnal as well as hypopycnal plumes. Several numerical tests will be presented. References [1] E. Audusse, M. Bristeau, B. Perthame, and J. Sainte-Marie. A multilayer Saint-Venant system with mass exchanges for shallow water flows. derivation and numerical validation. ESAIM: Mathematical Modelling and Numerical Analysis, 45(1):169-200, (2010). [2] E. Audusse, M.-O. Bristeau, M. Pelanti, and J. Sainte-Marie. Approximation of the hydrostatic Navier–Stokes system for density stratified flows by a multilayer model: Kinetic interpretation and numerical solution. Journal of Computational Physics, 230(9):3453-3478, (2011). [3] S. F. Bradford and N. D. Katopodes. Hydrodynamics of turbid underflows. i: Formulation and numerical
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Comparing multilayer brain networks between groups: Introducing graph metrics and recommendations.
Mandke, Kanad; Meier, Jil; Brookes, Matthew J; O'Dea, Reuben D; Van Mieghem, Piet; Stam, Cornelis J; Hillebrand, Arjan; Tewarie, Prejaas
2018-02-01
There is an increasing awareness of the advantages of multi-modal neuroimaging. Networks obtained from different modalities are usually treated in isolation, which is however contradictory to accumulating evidence that these networks show non-trivial interdependencies. Even networks obtained from a single modality, such as frequency-band specific functional networks measured from magnetoencephalography (MEG) are often treated independently. Here, we discuss how a multilayer network framework allows for integration of multiple networks into a single network description and how graph metrics can be applied to quantify multilayer network organisation for group comparison. We analyse how well-known biases for single layer networks, such as effects of group differences in link density and/or average connectivity, influence multilayer networks, and we compare four schemes that aim to correct for such biases: the minimum spanning tree (MST), effective graph resistance cost minimisation, efficiency cost optimisation (ECO) and a normalisation scheme based on singular value decomposition (SVD). These schemes can be applied to the layers independently or to the multilayer network as a whole. For correction applied to whole multilayer networks, only the SVD showed sufficient bias correction. For correction applied to individual layers, three schemes (ECO, MST, SVD) could correct for biases. By using generative models as well as empirical MEG and functional magnetic resonance imaging (fMRI) data, we further demonstrated that all schemes were sensitive to identify network topology when the original networks were perturbed. In conclusion, uncorrected multilayer network analysis leads to biases. These biases may differ between centres and studies and could consequently lead to unreproducible results in a similar manner as for single layer networks. We therefore recommend using correction schemes prior to multilayer network analysis for group comparisons. Copyright © 2017 Elsevier
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"{Deposition and characterization of multilayers on thin foil x-ray
DEFF Research Database (Denmark)
Hussain, A.M.; Joensen, K.D.; Hoeghoej, P.
1996-01-01
W/Si and Co/C multilayers have been deposited on epoxy- replicated Au mirrors from the ASTRO-E telescope project, SPectrum Roentgen Gamma (SRG) flight mirrors, DURAN glass substrates and Si witness wafers. A characterization of the multilayers with both hard x-rays and soft x-rays is presented. T...
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Designing multilayered nanoplatforms for SERS-based detection of genetically modified organisms
Uluok, Saadet; Guven, Burcu; Eksi, Haslet; Ustundag, Zafer; Tamer, Ugur; Boyaci, Ismail Hakki
2015-01-01
In this study, the multilayered surface-enhanced Raman spectroscopy (SERS) platforms were developed for the analysis of genetically modified organisms (GMOs). For this purpose, two molecules [11-mercaptoundecanoic acid (11-MUA) and 2-mercaptoethylamine (2-MEA)] were attached with Aurod and Auspherical nanoparticles to form multilayered constructions on the gold (Au)slide surface. The best multilayered platform structure was chosen depending on SERS enhancement, and this surface was characterised with atomic force microscopy (AFM) and attenuated total reflectance Fourier transform infrared spectroscopy. After the optimum multilayered SERS platform and nanoparticle interaction was identified, the oligonucleotides on the Aurod nanoparticles and Auslide were combined to determine target concentrations from the 5,5'-dithiobis (2-nitrobenzoic acid) (DTNB) signals using SERS. The correlation between the SERS intensities for DTNB and target concentrations was found to be linear within a range of 10 pM to 1 µM, and with a detection limit of 34 fM. The selectivity and specificity of the developed sandwich assay were tested using negative and positive controls, and nonsense and real sample studies. The obtained results showed that the multilayered SERS sandwich method allows for sensitive, selective, and specific detection of oligonucleotide sequences.
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Realistic absorption coefficient of each individual film in a multilayer architecture
Cesaria, M.; Caricato, A. P.; Martino, M.
2015-02-01
A spectrophotometric strategy, termed multilayer-method (ML-method), is presented and discussed to realistically calculate the absorption coefficient of each individual layer embedded in multilayer architectures without reverse engineering, numerical refinements and assumptions about the layer homogeneity and thickness. The strategy extends in a non-straightforward way a consolidated route, already published by the authors and here termed basic-method, able to accurately characterize an absorbing film covering transparent substrates. The ML-method inherently accounts for non-measurable contribution of the interfaces (including multiple reflections), describes the specific film structure as determined by the multilayer architecture and used deposition approach and parameters, exploits simple mathematics, and has wide range of applicability (high-to-weak absorption regions, thick-to-ultrathin films). Reliability tests are performed on films and multilayers based on a well-known material (indium tin oxide) by deliberately changing the film structural quality through doping, thickness-tuning and underlying supporting-film. Results are found consistent with information obtained by standard (optical and structural) analysis, the basic-method and band gap values reported in the literature. The discussed example-applications demonstrate the ability of the ML-method to overcome the drawbacks commonly limiting an accurate description of multilayer architectures.
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Ring-dot-shaped multilayer piezoelectric step-down transformers using PZT-based ceramics
Energy Technology Data Exchange (ETDEWEB)
Kim, Insung; Joo, Hyeonkyu; Song, Jaesung; Jeong, Soonjong; Kim, Minsoo [Korea Electrotechnology Research Institute, Changwon (Korea, Republic of)
2010-10-15
In this study, multilayer piezo stack transformers for switching mode power supply (SMPS) application were manufactured using 0.01Pb(Ni{sub 1/3}Nb{sub 2/3})O{sub 3} - 0.08Pb(Mn{sub 1/3}Nb{sub 2/3})O{sub 3} - 0.91Pb(Zr{sub 0.505}Ti{sub 0.495})O{sub 3} (PNN-PMN-PZT) ceramics. The voltage ratio of a multilayer piezo stack transformer showed a maximum at the resonance frequency of the input and then increased with increasing load resistance. The efficiency of the multilayer piezo stack transformer showed its highest value at around the matching load. The output power increased with increasing input voltage. The temperature of the multilayer piezo stack transformer increased with increasing output power and load resistance. The manufactured multilayer piezo stack transformer could be used up to 5 W at a resonance frequency of 70.25 kHz for SMPS application because the temperature rise from room temperature is believed to about 20 .deg. C and because the transformer is electrically stable. The newly-developed ring-dot-type step-down multilayer piezo stack transformer shows possible applications as SMPS for electronic power sources with excellent input-to-output properties.
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Mo/Si multilayers with enhanced TiO II- and RuO II-capping layers
Yulin, Sergiy; Benoit, Nicolas; Feigl, Torsten; Kaiser, Norbert; Fang, Ming; Chandhok, Manish
2008-03-01
The lifetime of Mo/Si multilayer-coated projection optics is one of the outstanding issues on the road of commercialization of extreme-ultraviolet lithography (EUVL). The application of Mo/Si multilayer optics in EUVL requires both sufficient radiation stability and also the highest possible normal-incidence reflectivity. A serious problem of conventional high-reflective Mo/Si multilayers capped by silicon is the considerable degradation of reflective properties due to carbonization and oxidation of the silicon surface layer under exposure by EUV radiation. In this study, we focus on titanium dioxide (TiO II) and ruthenium dioxide (RuO II) as promising capping layer materials for EUVL multilayer coatings. The multilayer designs as well as the deposition parameters of the Mo/Si systems with different capping layers were optimized in terms of maximum peak reflectivity at the wavelength of 13.5 nm and longterm stability under high-intensive irradiation. Optimized TiO II-capped Mo/Si multilayer mirrors with an initial reflectivity of 67.0% presented a reflectivity drop of 0.6% after an irradiation dose of 760 J/mm2. The reflectivity drop was explained by the partial oxidation of the silicon sub-layer. No reflectivity loss after similar irradiation dose was found for RuO II-capped Mo/Si multilayer mirrors having initial peak reflectivity of 66%. In this paper we present data on improved reflectivity of interface-engineered TiO II- and RuO II-capped Mo/Si multilayer mirrors due to the minimization of both interdiffusion processes inside the multilayer stack and absorption loss in the oxide layer. Reflectivities of 68.5% at the wavelength of 13.4 nm were achieved for both TiO II- and RuO II-capped Mo/Si multilayer mirrors.
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Canto, C. E.; Andrade, E.; Rocha, M. F.; Alemón, B.; Flores, M.
2017-09-01
The tribocorrosion resistance and adherence of multilayer coatings of TiAlPtN/TiAlN/TiAl synthesized by PVD reactive magnetron sputtering over a CoCrMo alloy substrate in 10 periods of 30 min each were analyzed and compared to those of the substrate alone and to that of a TiAlPtN single layer coating of the same thickness. The objective of the present work was to create multilayers with different amounts of Pt in order to enhance the tribocorrosion resistance of a biomedical alloy of CoCrMo. Tribocorrosion tests were performed using Simulated Body Fluid (SBF) at typical body temperature with a tribometer in a pin on disk test. The elemental composition and thickness of the coating which behave better at the tribocorrosion tests were evaluated by means of RBS (Rutherford Backscattering Spectroscopy) IBA (Ion Beam Analysis) technique, using an alpha particles beam of 1.8 MeV, before and after the reciprocating motion in the tribocorrosion test. In order to simulate the elemental profile of the samples, the SIMNRA simulation computer code was used. Measurements of the adhesion of the coatings to the substrate were carried on by means of a scratch test using a tribometer. By taking micrographs of the produced tracks, the critical loads at which the coatings are fully separated from the substrate were determined. From these tests it was observed that a coating with 10 min of TiAlPtN in a TiAlPtN/TiAl period of 30 min in multilayers of 10 periods and with an average thickness of 145 nm for the TiAlPtN nanolayers had the best tribocorrosion resistance behavior, compared to that of the CoCrMo alloy. The RBS experiments showed a reduction of the thickness of the films along with some loss of the multilayer structure after the reciprocating motion. The adhesion tests indicated that the multilayer with the average TiAlPtN thickness of 145 nm displayed the highest critical load. These results indicate a high correlation between the adherence and the tribocorrosion behavior.
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Spin-resolved unpolarized neutron off-specular scattering for magnetic multilayer studies
Lauter, H J; Toperverg, B P; Romashev, L; Ustinov, V; Kravtsov, E; Vorobiev, A; Major, J; Nikonov, O A
2002-01-01
The capabilities of the method of using unpolarized neutron off-specular scattering for investigation of magnetic structures in exchange-coupled magnetic multilayers are thoroughly examined. It is demonstrated that strong anomalies in spin-flip selective scattering processes originating from magnetic fluctuations enables a straightforward determination of the coupling angle between the magnetization direction of successive Fe layers in Fe/Cr multilayers. A complete quantitative 2-dimensional data analysis of specular and off-specular scattering has been employed to provide detailed information on the lateral and transverse magnetization arrangement in the multilayer. (orig.)
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Anomalous magnetoresistance in Fibonacci multilayers.
Energy Technology Data Exchange (ETDEWEB)
Machado, L. D.; Bezerra, C. G.; Correa, M. A.; Chesman, C.; Pearson, J. E.; Hoffmann, A. (Materials Science Division); (Universidade Federal do Rio Grande do Norte)
2012-01-01
We theoretically investigated magnetoresistance curves in quasiperiodic magnetic multilayers for two different growth directions, namely, [110] and [100]. We considered identical ferromagnetic layers separated by nonmagnetic layers with two different thicknesses chosen based on the Fibonacci sequence. Using parameters for Fe/Cr multilayers, four terms were included in our description of the magnetic energy: Zeeman, cubic anisotropy, bilinear coupling, and biquadratic coupling. The minimum energy was determined by the gradient method and the equilibrium magnetization directions found were used to calculate magnetoresistance curves. By choosing spacers with a thickness such that biquadratic coupling is stronger than bilinear coupling, unusual behaviors for the magnetoresistance were observed: (i) for the [110] case, there is a different behavior for structures based on even and odd Fibonacci generations, and, more interesting, (ii) for the [100] case, we found magnetic field ranges for which the magnetoresistance increases with magnetic field.
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Surface modification of multilayer graphene using Ga ion irradiation
Energy Technology Data Exchange (ETDEWEB)
Wang, Quan, E-mail: wangq@mail.ujs.edu.cn [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Shao, Ying; Ge, Daohan; Ren, Naifei [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); Yang, Qizhi [School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013 (China); State key laboratory of Robotics, Chinese Academy of Sciences, Shengyang 110000 (China)
2015-04-28
The effect of Ga ion irradiation intensity on the surface of multilayer graphene was examined. Using Raman spectroscopy, we determined that the irradiation caused defects in the crystal structure of graphene. The density of defects increased with the increase in dwell times. Furthermore, the strain induced by the irradiation changed the crystallite size and the distance between defects. These defects had the effect of doping the multilayer graphene and increasing its work function. The increase in work function was determined using contact potential difference measurements. The surface morphology of the multilayer graphene changed following irradiation as determined by atomic force microscopy. Additionally, the adhesion between the atomic force microscopy tip and sample increased further indicating that the irradiation had caused surface modification, important for devices that incorporate graphene.
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Design considerations for energy efficient, resilient, multi-layer networks
DEFF Research Database (Denmark)
Fagertun, Anna Manolova; Hansen, Line Pyndt; Ruepp, Sarah Renée
2016-01-01
measures. In this complex problem, considerations such as client traffic granularity, applied grooming policies and multi-layer resiliency add even more complexity. A commercially available network planning tool is used to investigate the interplay between different methods for resilient capacity planning......This work investigates different network design considerations with respect to energy-efficiency, under green-field resilient multi-layer network deployment. The problem of energy efficient, reliable multi-layer network design is known to result in different trade-offs between key performance....... Switching off low-utilized transport links has been investigated via a pro-active re-routing applied during the network planning. Our analysis shows that design factors such as the applied survivability strategy and the applied planning method have higher impact on the key performance indicators compared...
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Multilayer Photonic Crystal for Spectral Narrowing of Emission
Directory of Open Access Journals (Sweden)
Zhanfang LIU
2017-08-01
Full Text Available Multilayer colloidal crystal has been prepared by the layer-by-layer deposition of silica microspheres on a glass slide. Each layer is a slab consisting of a fcc close-packed colloidal arrays. By properly choosing the sizes of spheres, the whole spectral feature of multilayer colloidal crystal can be tuned. Here, we engineered a multilayer superlattice structure with an effective passband between two stop bands. This gives a strong narrowing effect on emission spectrum. With the stop bands at the shortwave and longwave edges of emission spectrum, the passband in the central wavelength region can be regarded as a strong decrease of suppression effect and enhancement of a narrow wavelength region of emission. The spectral narrowing modification effect of suitably engineered colloidal crystals shows up their importance in potential application as optical filters and lasing devices.DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16320
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Research on the Multilayer Free Damping Structure Design
Directory of Open Access Journals (Sweden)
Jie Meng
2018-01-01
Full Text Available The aim of this paper is to put forward a design model for multilayer free damping structures. It sets up a mathematical model and deduces the formula for its structural loss factor η and analyzes the change rules of η along with the change rate of the elastic modulus ratio q1, the change rate of the loss factors of damping materials q2, and the change rate of the layer thickness ratio q3 under the condition with the layer thickness ratio h2=1,3,5,10 by software MATLAB. Based on three specific damping structures, the mathematical model is verified through ABAQUS. With the given structural loss factor (η≥2 and the layer number (n=3,4,5,6, 34 kinds of multilayer free damping structures are then presented. The study is meant to provide a more flexible and more diverse design solution for multilayer free damping structures.
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Three dimensional multilayer solenoid microcoils inside silica glass
Meng, Xiangwei; Yang, Qing; Chen, Feng; Shan, Chao; Liu, Keyin; Li, Yanyang; Bian, Hao; Si, Jinhai; Hou, Xun
2016-01-01
Three dimensional (3D) solenoid microcoils could generate uniform magnetic field. Multilayer solenoid microcoils are highly pursued for strong magnetic field and high inductance in advanced magnetic microsystems. However, the fabrication of the 3D multilayer solenoid microcoils is still a challenging task. In this paper, 3D multilayer solenoid microcoils with uniform diameters and high aspect ratio were fabricated in silica glass. An alloy (Bi/In/Sn/Pb) with high melting point was chosen as the conductive metal to overcome the limitation of working temperature and improve the electrical property. The inductance of the three layers microcoils was measured, and the value is 77.71 nH at 100 kHz and 17.39 nH at 120 MHz. The quality factor was calculated, and it has a value of 5.02 at 120 MHz. This approach shows an improvement method to achieve complex 3D metal microstructures and electronic components, which could be widely integrated in advanced magnetic microsystems.
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Fabrication and Characteristics of Al/PTFE Multilayers and Application in Micro-initiator
Zhang, Yuxin; Jiang, Hongchuan; Zhao, Xiaohui; Zhang, Wanli; Li, Yanrong
2017-12-01
In this paper, a micro-initiator was designed and fabricated by integrating Al/PTFE multilayers with a Cu film bridge. The regularity layer structure and interface composition of Al/PTFE multilayers was analysed by transmission electron microscope and X-ray photoelectron spectroscopy, respectively. The heat release reaction in Al/PTFE multilayers can be triggered with reaction temperature of 430 °C, and the overall heat of reaction is 3192 J/g. Al/PTFE multilayers with bilayer thickness of 200 nm was alternately deposited on a Cu film bridge to improve the electric explosion performances. Compared to Cu film bridge, the Al/PTFE/Cu integrated film bridge exhibits improved performances with longer explosion duration time, more violent explosion phenomenon and larger quantities of ejected product particles.
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Structural evolution of Ti/TiC multilayers
International Nuclear Information System (INIS)
Dahan, I.; Frage, N.; Dariel, M.P.
2004-01-01
Hard coatings based on metal/ceramic multilayers with periods in the nanometer range have been shown to possess some potential for improved tribological and mechanical properties. The present work is concerned with the structural evolution of (Ti/TiC) multilayers. Two kinds of multilayers consisting of 30 equithick (40 nm)TiC layers and 20 and 60 nm thick Ti layers, respectively, were sputter deposited on Mo substrates. The structural and the compositional evolution of these multilayers were examined by x-ray diffraction, transition electron microscopy (TEM), high-resolution TEM, Auger electron microscopy spectroscopy and differential thermal analysis (DTA), in the as-deposited state and after various heat treatments up to 500 deg. C. Initially, the Ti layers had a crystalline columnar grain structure displaying a (002) texture. The TiC layers displayed weak crystallinity with a pronounced (111) texture. In the course of the heat treatments, carbon diffused from the carbide layer into the adjacent Ti layers transforming the latter into off-stoichiometric TiC x with x≅0.5 and simultaneously depleting the carbon content of the initial carbide layer. The formed TiC x layers maintained the textural relationship with the neighboring TiC layers, consistent with a transformation that involved only a ABAB to ABC stacking change of the Ti sublattice. Increased mobility of the Ti atoms in carbon-depleted original TiC layers led to their full or partial recrystallization. The thermal effects associated both with the transformation of Ti layers into TiC, due to the influx of carbon atoms, and with the recrystallization of the original TiC layers were clearly revealed by the DTA measurements
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Magnetic studies of spin wave excitations in Fe/Mn multilayers
Energy Technology Data Exchange (ETDEWEB)
Salhi, H. [LPMMAT, Faculté des Sciences Ain Chock, Université Hassan II de Casablanca, B.P. 5366 Mâarif, Casablanca (Morocco); LMPG, Ecole supérieure de technologie, Université Hassan de Casablanca, Casablanca (Morocco); Moubah, R.; El Bahoui, A.; Lassri, H. [LPMMAT, Faculté des Sciences Ain Chock, Université Hassan II de Casablanca, B.P. 5366 Mâarif, Casablanca (Morocco)
2017-04-15
The structural and magnetic properties of Fe/Mn multilayers grown by thermal evaporation technique were investigated by transmission electron microscopy, vibrating sample magnetometer and spin wave theory. Transmission electron microscopy shows that the Fe and Mn layers are continuous with a significant interfacial roughness. The magnetic properties of Fe/Mn multilayers were studied for various Fe thicknesses (t{sub Fe}). The change of magnetization as a function of temperature is well depicted by a T{sup 3/2} law. The Fe spin-wave constant was extracted and found to be larger than that reported for bulk Fe, which we attribute to the fluctuation of magnetic moments at the interface, due to the interfacial roughness. The experimental M (T) data were satisfactory fitted for multilayers with different Fe thicknesses; and several exchange interactions were extracted. - Highlights: • The structural and magnetic properties of Fe/Mn multilayers were studied. • Fe and Mn layers are continuous with an important interfacial roughness. • The Fe spin-wave constant is larger than that reported for bulk Fe due to the fluctuation of the interfacial magnetic moments.
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Magnetic studies of spin wave excitations in Fe/Mn multilayers
International Nuclear Information System (INIS)
Salhi, H.; Moubah, R.; El Bahoui, A.; Lassri, H.
2017-01-01
The structural and magnetic properties of Fe/Mn multilayers grown by thermal evaporation technique were investigated by transmission electron microscopy, vibrating sample magnetometer and spin wave theory. Transmission electron microscopy shows that the Fe and Mn layers are continuous with a significant interfacial roughness. The magnetic properties of Fe/Mn multilayers were studied for various Fe thicknesses (t Fe ). The change of magnetization as a function of temperature is well depicted by a T 3/2 law. The Fe spin-wave constant was extracted and found to be larger than that reported for bulk Fe, which we attribute to the fluctuation of magnetic moments at the interface, due to the interfacial roughness. The experimental M (T) data were satisfactory fitted for multilayers with different Fe thicknesses; and several exchange interactions were extracted. - Highlights: • The structural and magnetic properties of Fe/Mn multilayers were studied. • Fe and Mn layers are continuous with an important interfacial roughness. • The Fe spin-wave constant is larger than that reported for bulk Fe due to the fluctuation of the interfacial magnetic moments.
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Construction of pegylated multilayer architectures via (strept)avidin/biotin interactions
International Nuclear Information System (INIS)
Dai Zhifei; Wilson, John T.; Chaikof, Elliot L.
2007-01-01
Pegylated multilayer architectures were fabricated as films on planar substrates, as shells on colloidal particles, or as free-standing hollow capsules using layer-by-layer (LbL) self-assembly of biotinylated poly-L-lysine (PLL) and (strept)avidin. Poly(ethylene glycol) (PEG) was incorporated into the multilayer architectures by assembly with biotin-derivatized poly(L-lysine)-g-poly(ethylene glycol)(PPB). Stepwise growth of multilayers was followed by UV-vis spectroscopy and the formation of core-shells and hollow capsules characterized by means of confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Both absorbance and TEM data suggest that approximately two layers of FITC-avidin were adsorbed with each surface deposition. In contrast, use of unmodified PLL did not lead to formation of multilayer coatings, confirming that (strept)avidin-biotin interactions were responsible for film growth even in the presence of electrostatic repulsive forces between PLL and avidin and the steric hindrance of associated PEG chains. This technique provides new opportunities for the generation of robust films with tailored interfacial binding and transport properties
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Performance of multilayer coated silicon pore optics
Ackermann, M. D.; Collon, M. J.; Jensen, C. P.; Christensen, F. E.; Krumrey, M.; Cibik, L.; Marggraf, S.; Bavdaz, M.; Lumb, D.; Shortt, B.
2010-07-01
The requirements for the IXO (International X-ray Observatory) telescope are very challenging in respect of angular resolution and effective area. Within a clear aperture with 1.7 m > R > 0.25 m that is dictated by the spacecraft envelope, the optics technology must be developed to satisfy simultaneously requirements for effective area of 2.5 m2 at 1.25 keV, 0.65 m2 at 6 keV and 150 cm2 at 30 keV. The reflectivity of the bare mirror substrate materials does not allow these requirements to be met. As such the IXO baseline design contains a coating layout that varies as a function of mirror radius and in accordance with the variation in grazing incidence angle. The higher energy photon response is enhanced through the use of depth-graded multilayer coatings on the inner radii mirror modules. In this paper we report on the first reflectivity measurements of wedged ribbed silicon pore optics mirror plates coated with a depth graded W/Si multilayer. The measurements demonstrate that the deposition and performance of the multilayer coatings is compatible with the SPO production process.
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SnO2/PPy Screen-Printed Multilayer CO2 Gas Sensor
Directory of Open Access Journals (Sweden)
S.A. WAGHULEY
2007-05-01
Full Text Available Tin dioxide (SnO2 plays a dominant role in solid state gas sensors and exhibit sensitivity towards oxidizing and reducing gases by a variation of its electrical properties. The electrical conducting polymer-polypyrrole (PPy has high anisotropy of electrical conduction and used as a gas sensor. SnO2/PPy multilayer, pure SnO2, pure PPy sensors were prepared by screen-printing method on Al2O3 layer followed by glass substrate. The sensors were used for different concentration (ppm of CO2 gas investigation at room temperature (303 K. The sensitivity of SnO2/PPy multilayer sensor was found to be higher, compared with pure SnO2 and pure PPy sensors. The multilayer sensor exhibited improved stability. The response and recovery time of multilayer sensor were found to be ~2 min and ~10 min respectively.
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Stronger multilayer acrylic dielectric elastomer actuators with silicone gel coatings
Lau, Gih-Keong; La, Thanh-Giang; Sheng-Wei Foong, Ervin; Shrestha, Milan
2016-12-01
Multilayer dielectric elastomer actuators (DEA) perform worst off than single-layer DEAs due to higher susceptibility to electro-thermal breakdown. This paper presents a hot-spot model to predict the electro-thermal breakdown field of DEAs and its dependence on thermal insulation. To inhibit the electrothermal breakdown, silicone gel coating was applied as barrier coating to multilayer acrylic DEA. The gel coating helps suppress the electro-thermally induced puncturing of DEA membrane at the hot spot. As a result, the gel-coated DEAs, in either a single layer or a multilayer stack, can produce 30% more isometric stress change as compared to those none-coated. These gel-coated acrylic DEAs show great potential to make stronger artificial muscles.
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Substrate and coating defect planarization strategies for high-laser-fluence multilayer mirrors
International Nuclear Information System (INIS)
Stolz, Christopher J.; Wolfe, Justin E.; Mirkarimi, Paul B.; Folta, James A.; Adams, John J.; Menor, Marlon G.; Teslich, Nick E.; Soufli, Regina; Menoni, Carmen S.; Patel, Dinesh
2015-01-01
Planarizing or smoothing over nodular defects in multilayer mirrors can be accomplished by a discrete deposit-and-etch process that exploits the angle-dependent etching rate of optical materials. Typically, nodular defects limit the fluence on mirrors irradiated at 1064 nm with 10 ns pulse lengths due to geometrically- and interference-induced light intensification. Planarized hafina/silica multilayer mirrors have demonstrated > 125 J/cm 2 laser resistance for single-shot testing and 50 J/cm 2 for multi-shot testing for nodular defects originating on the substrate surface. Two planarization methods were explored: thick planarization layers on the substrate surface and planarized silica layers throughout the multilayer in which only the silica layers that are below one half of the incoming electric field value are etched. This paper also describes the impact of planarized defects that are buried within the multilayer structure compared to planarized substrate particulate defects. - Highlights: • Defect planarization significantly improves multilayer mirror laser resistance • Substrate and coating defects have both been effectively planarized • Single and multishot laser resistance improvement was demonstrated
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A Magnetron Sputter Deposition System for the Development of X-Ray Multilayer Optics
Broadway, David
2015-01-01
The project objective is to establish the capability to deposit multilayer structures for x-ray, neutron, and extreme ultraviolet (EUV) optic applications through the development of a magnetron sputtering deposition system. A specific goal of this endeavor is to combine multilayer deposition technology with the replication process in order to enhance NASA Marshall Space Flight Center's (MSFC's) position as a world leader in the design of innovative x-ray instrumentation through the development of full shell replicated multilayer optics. The development of multilayer structures are absolutely necessary in order to advance the field of x-ray astronomy by pushing the limit for observing the universe to ever-increasing photon energies (i.e., up to 200 keV or higher), well beyond Chandra's (approx.10 keV) and NuStar's (approx.75 keV) capability. The addition of multilayer technology would significantly enhance the x-ray optics capability at MSFC and allow NASA to maintain its world leadership position in the development, fabrication, and design of innovative x-ray instrumentation, which would be the first of its kind by combining multilayer technology with the mirror replication process. This marriage of these technologies would allow astronomers to see the universe in a new light by pushing to higher energies that are out of reach with today's instruments. To this aim, a magnetron vacuum sputter deposition system for the deposition of novel multilayer thin film x-ray optics is proposed. A significant secondary use of the vacuum deposition system includes the capability to fabricate multilayers for applications in the field of EUV optics for solar physics, neutron optics, and x-ray optics for a broad range of applications including medical imaging.
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A Magnetron Sputter Deposition System for the Development of Multilayer X-Ray Optics
Broadway, David; Ramsey, Brian; Gubarev, Mikhail
2014-01-01
The proposal objective is to establish the capability to deposit multilayer structures for x-ray, neutron, and EUV optic applications through the development of a magnetron sputtering deposition system. A specific goal of this endeavor is to combine multilayer deposition technology with the replication process in order to enhance the MSFC's position as a world leader in the design of innovative X-ray instrumentation through the development of full shell replicated multilayer optics. The development of multilayer structures is absolutely necessary in order to advance the field of X-ray astronomy by pushing the limit for observing the universe to ever increasing photon energies (i. e. up to 200 keV or higher); well beyond Chandra (approx. 10 keV) and NuStar's (approx. 75 keV) capability. The addition of multilayer technology would significantly enhance the X-ray optics capability at MSFC and allow NASA to maintain its world leadership position in the development, fabrication and design of innovative X-ray instrumentation which would be the first of its kind by combining multilayer technology with the mirror replication process. This marriage of these technologies would allow astronomers to see the universe in a new light by pushing to higher energies that are out of reach with today's instruments.To this aim, a magnetron vacum sputter deposition system for the deposition of novel multilayer thin film X-ray optics is proposed. A significant secondary use of the vacuum deposition system includes the capability to fabricate multilayers for applications in the field of EUV optics for solar physics, neutron optics, and X-ray optics for a broad range of applications including medical imaging.
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Luna, Vicki Ann; Hall, Tony J; King, Debbie S; Cannons, Andrew C
2010-05-01
To test the activity of two copper-based biocides, CuAL42 and CuWB50, and benzalkonium chloride against 169 isolates of methicillin-resistant Staphylococcus aureus (MRSA) pulsotype USA300, a virulent, multiply resistant, widespread clone in the USA. Tests including MIC, MBC and time-kill studies were performed multiple times. The MIC range, MIC(50) and MIC(90) (0.59-18.75, 4.69 and 4.69 ppm, respectively) and the MBC range, MBC(50) and MBC(90) (1.17-18.75, 4.69 and 9.38 ppm, respectively) for CuAL42 were identical with those obtained with CuWB50, except that the MBC range for CuWB50 was wider (0.59-37.5 ppm). In time-kill studies, a 6 log(10) reduction of cfu was achieved within 1 h (150 ppm) and 0.5 h (300 ppm) for CuAL42, and 1.5 h (150 ppm) and 0.75 h (300 ppm) for CuWB50. Both copper-based biocides can effectively kill USA300 MRSA and may facilitate the eradication of the organism from healthcare settings.
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Influence of Fe underlayers on stress evolution of Ti in Ti/Fe multilayers
Energy Technology Data Exchange (ETDEWEB)
Wan, Li; Thompson, Gregory, E-mail: gthompson@eng.ua.edu [Department of Metallurgical Engineering, The University of Alabama, Tuscaloosa, Alabama 35487-0202 (United States)
2016-11-15
A series of 40–2 nm bilayer spacing Ti/Fe multilayers were sputter-deposited. As the length scale of individual Ti layers equaled to 2 nm, Ti phase transforms from a hexagonal close packed (hcp)-to-body centered cubic (bcc) crystal structures for equal layer thicknesses in Ti/Fe multilayers. Further equal reductions in bilayer spacing to less than 1 nm resulted in an additional transformation from a crystalline to amorphous structure. Atom probe tomography reveals significant intermixing between layers which contributes to the observed phase transformations. Real-time, intrinsic growth stress measurements were also performed to relate the adatom mobility to these phase transformations. For the hcp Ti/bcc Fe multilayers of equivalent volume fractions, the multilayers undergo an overall tensile stress state to a compressive stress state with decreasing bilayer thickness for the multilayers. When the above phase transformations occurred, a modest reduction in the overall compressive stress of the multilayer was noted. Depending on the Fe thickness, the Ti growth was observed to be a tensile to compressive growth change to a purely compressive growth for thinner bilayer spacing. Fe retained a tensile growth stress regardless of the bilayer spacing studied.
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Interface interaction and wetting of Sc2O3 exposed to Cu-Al and Cu-Ti melts
International Nuclear Information System (INIS)
Barzilai, S.; Nagar, H.; Froumin, N.; Frage, N.; Aizenshtein, M.
2009-01-01
Scandia is a thermodynamically stable oxide and could be used as a structural material for a crucible in order to avoid a melt contamination. In the present study wetting experiments of Cu-Al and Cu-Ti melts on Scandia substrate were preformed at 1423 K by a sessile drop method. It was established that Al and Ti additions lead to the improved wetting and that the final contact angle decreases with increasing the additives concentration. For Al containing melts, the contact angle changes gradually with time, and a relatively thick interaction layer, which consists of Al 2 O 3 , Sc 2 O 3 , and metallic channels, was formed at the Sc 2 O 3 /Cu-Al interface. For Ti containing melts, the final contact angle is achieved already during heating, and an extremely thin layer based on a Ti-Sc-O compound was detected by AES at the Sc 2 O 3 /Cu-Ti interface. The results of a thermodynamic analysis, which takes into account the formation free energy of the oxides, involved in the systems, and the thermodynamic properties of the liquid solutions are in a good agreement with the experimental observations. (orig.)
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A chemically stable PVD multilayer encapsulation for lithium microbatteries
International Nuclear Information System (INIS)
Ribeiro, J F; Sousa, R; Cunha, D J; Vieira, E M F; Goncalves, L M; Silva, M M; Dupont, L
2015-01-01
A multilayer physical vapour deposition (PVD) thin-film encapsulation method for lithium microbatteries is presented. Lithium microbatteries with a lithium cobalt oxide (LiCoO 2 ) cathode, a lithium phosphorous oxynitride (LiPON) electrolyte and a metallic lithium anode are under development, using PVD deposition techniques. Metallic lithium film is still the most common anode on this battery technology; however, it presents a huge challenge in terms of material encapsulation (lithium reacts with almost any materials deposited on top and almost instantly begins oxidizing in contact with atmosphere). To prove the encapsulation concept and perform all the experiments, lithium films were deposited by thermal evaporation technique on top of a glass substrate, with previously patterned Al/Ti contacts. Three distinct materials, in a multilayer combination, were tested to prevent lithium from reacting with protection materials and atmosphere. These multilayer films were deposited by RF sputtering and were composed of lithium phosphorous oxide (LiPO), LiPON and silicon nitride (Si 3 N 4 ). To complete the long-term encapsulation after breaking the vacuum, an epoxy was applied on top of the PVD multilayer. In order to evaluate oxidation state of lithium films, the lithium resistance was measured in a four probe setup (cancelling wires/contact resistances) and resistivity calculated, considering physical dimensions. A lithium resistivity of 0.16 Ω μm was maintained for more than a week. This PVD multilayer exonerates the use of chemical vapour deposition (CVD), glove-box chambers and sample manipulation between them, significantly reducing the fabrication cost, since battery and its encapsulation are fabricated in the same PVD chamber. (paper)
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A chemically stable PVD multilayer encapsulation for lithium microbatteries
Ribeiro, J. F.; Sousa, R.; Cunha, D. J.; Vieira, E. M. F.; Silva, M. M.; Dupont, L.; Goncalves, L. M.
2015-10-01
A multilayer physical vapour deposition (PVD) thin-film encapsulation method for lithium microbatteries is presented. Lithium microbatteries with a lithium cobalt oxide (LiCoO2) cathode, a lithium phosphorous oxynitride (LiPON) electrolyte and a metallic lithium anode are under development, using PVD deposition techniques. Metallic lithium film is still the most common anode on this battery technology; however, it presents a huge challenge in terms of material encapsulation (lithium reacts with almost any materials deposited on top and almost instantly begins oxidizing in contact with atmosphere). To prove the encapsulation concept and perform all the experiments, lithium films were deposited by thermal evaporation technique on top of a glass substrate, with previously patterned Al/Ti contacts. Three distinct materials, in a multilayer combination, were tested to prevent lithium from reacting with protection materials and atmosphere. These multilayer films were deposited by RF sputtering and were composed of lithium phosphorous oxide (LiPO), LiPON and silicon nitride (Si3N4). To complete the long-term encapsulation after breaking the vacuum, an epoxy was applied on top of the PVD multilayer. In order to evaluate oxidation state of lithium films, the lithium resistance was measured in a four probe setup (cancelling wires/contact resistances) and resistivity calculated, considering physical dimensions. A lithium resistivity of 0.16 Ω μm was maintained for more than a week. This PVD multilayer exonerates the use of chemical vapour deposition (CVD), glove-box chambers and sample manipulation between them, significantly reducing the fabrication cost, since battery and its encapsulation are fabricated in the same PVD chamber.
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Design and application of multilayer monolithic microwave integrated circuit transformers
Energy Technology Data Exchange (ETDEWEB)
Economides, S.B
1999-07-01
The design and performance of planar spiral transformers, using multilayer GaAs and silicon MMIC technology, are presented. This multilayer technology gives new opportunities for improving the performance of planar transformers, couplers and baluns. Planar transformers have high parasitic resistance and capacitance and low levels of coupling. Using multilayer technology these problems are overcome by applying a multilayer structure of three metal layers separated by two polyimide dielectric layers. The improvements gained by placing the conductors on different metal layers, and using conductors raised on polyimide layers for low capacitance, have been investigated. The circuits were fabricated using a novel experimental fabrication process, which uses entirely standard materials and techniques and is compatible with BJT's and silicon-germanium HBT's. The transformers were all characterised up to 20 GHz using RF-on-wafer measurements. They demonstrated good performance, considering the experimental nature of in-house multilayer technology and the difficulties in simulating these three-dimensional new geometries. With high resistivity substrates, the silicon components achieved virtually the same performance as their gallium arsenide counterparts. The transformers were then used in simulations of transformer-coupled HBT amplifier circuits, to demonstrate their capabilities. It was shown that these circuits present good performance compared to standard off-the shelf component circuits and are very promising for use in most multilayer MMIC applications. The structures were further used in coupling configurations, and applied in balun circuits and pushpull amplifiers. The spiral transformer coupler can operate at low frequencies without using up much chip area. In a balun configuration, the balun can compensate for coupling and phase imbalance and operates over 5 to 15 GHz. The spiral coupler does not always need multilayer processing, so the balun may be
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Origin of perpendicular magnetic anisotropy in Co/Ni multilayers
Arora, M.; Hübner, R.; Suess, D.; Heinrich, B.; Girt, E.
2017-07-01
We studied the variation in perpendicular magnetic anisotropy of (111) textured Au /N ×[Co /Ni ]/Au films as a function of the number of bilayer repeats N . The ferromagnetic resonance and superconducting quantum interference device magnetometer measurements show that the perpendicular magnetic anisotropy of Co/Ni multilayers first increases with N for N ≤10 and then moderately decreases for N >10 . The model we propose reveals that the decrease of the anisotropy for N reduction in the magnetoelastic and magnetocrystalline anisotropies. A moderate decrease in the perpendicular magnetic anisotropy for N >10 is due to the reduction in the magnetocrystalline and the surface anisotropies. To calculate the contribution of magnetoelastic anisotropy in the Co/Ni multilayers, in-plane and out-of-plane x-ray diffraction measurements are performed to determine the spacing between Co/Ni (111) and (220) planes. The magnetocrystalline bulk anisotropy is estimated from the difference in the perpendicular and parallel g factors of Co/Ni multilayers that are measured using the in-plane and out-of-plane ferromagnetic resonance measurements. Transmission electron microscopy has been used to estimate the multilayer film roughness. These values are used to calculate the roughness-induced surface and magnetocrystalline anisotropy coefficients as a function of N .
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Multilayer Controller for Outdoor Vehicle
DEFF Research Database (Denmark)
Reske-Nielsen, Anders; Mejnertsen, Asbjørn; Andersen, Nils Axel
2006-01-01
A full software and hardware solution has been designed, implemented and tested for control of a small agricultural automatic tractor. The objective was to realise a user-friendly, multi-layer controller architecture for an outdoor platform. The collaborative research work was done as a part of a...
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Modeling Macroscopic Shape Distortions during Sintering of Multi-layers
DEFF Research Database (Denmark)
Tadesse Molla, Tesfaye
as to help achieve defect free multi-layer components. The initial thickness ratio between the layers making the multi-layer has also significant effect on the extent of camber evolution depending on the material systems. During sintering of tubular bi-layer structures, tangential (hoop) stresses are very...... large compared to radial stresses. The maximum value of hoop stress, which can generate processing defects such as cracks and coating peel-offs, occurs at the beginning of the sintering cycle. Unlike most of the models defining material properties based on porosity and grain size only, the multi...... (firing). However, unintended features like shape instabilities of samples, cracks or delamination of layers may arise during sintering of multi-layer composites. Among these defects, macroscopic shape distortions in the samples can cause problems in the assembly or performance of the final component...
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Dye, Scott A.
2015-01-01
New NASA vehicles, such as Earth Departure Stage (EDS), Orion, landers, and orbiting fuel depots, need improved cryogenic propellant transfer and storage for long-duration missions. Current cryogen feed line multilayer insulation (MLI) performance is 10 times worse per area than tank MLI insulation. During each launch, cryogenic piping loses approximately 150,000 gallons (equivalent to $300,000) in boil-off during transfer, chill down, and ground hold. Quest Product Development Corp., teaming with Ball Aerospace, developed an innovative advanced insulation system, Wrapped MLI (wMLI), to provide improved thermal insulation for cryogenic feed lines. wMLI is high-performance multilayer insulation designed for cryogenic piping. It uses Quest's innovative discrete-spacer technology to control layer spacing/ density and reduce heat leak. The Phase I project successfully designed, built, and tested a wMLI prototype with a measured heat leak 3.6X lower than spiral-wrapped conventional MLI widely used for piping insulation. A wMLI prototype had a heat leak of 7.3 W/m2, or 27 percent of the heat leak of conventional MLI (26.7 W/m2). The Phase II project is further developing wMLI technology with custom, molded polymer spacers and advancing the product toward commercialization via a rigorous testing program, including developing advanced vacuuminsulated pipe for ground support equipment.
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An ultra-broadband multilayered graphene absorber
Amin, Muhammad; Farhat, Mohamed; Bagci, Hakan
2013-01-01
An ultra-broadband multilayered graphene absorber operating at terahertz (THz) frequencies is proposed. The absorber design makes use of three mechanisms: (i) The graphene layers are asymmetrically patterned to support higher order surface plasmon
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The stress-strain relationship for multilayers of the high Tc superconducting oxides
International Nuclear Information System (INIS)
Hidaka, H.; Yamamura, H.
1988-01-01
This paper reports the calculation of the stress-strain relationship for multilayers of the high Tc superconducting oxides. The elucidation of this relationship is expected quite helpful for the preparation of high-quality multilayers of these materials. This calculation is possible to do in the same way of Timoshenko's bi-metal treatment. The authors did computation of the residual stress and strain, and the state of stress and strain for these multilayers has been acquired in detail by this calculation
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Thermal performance measurement and application of a multilayer insulator for emergency architecture
International Nuclear Information System (INIS)
Salvalai, Graziano; Imperadori, Marco; Scaccabarozzi, Diego; Pusceddu, Cristina
2015-01-01
Lightness coupled with a quick assembly method is crucial for emergency architecture in post-disaster area where accessibility and action time play a huge barer to rescue people. In this prospective, the following work analyses the potentiality (technological and thermal performances) of multilayer insulator for a new shelter envelope able to provide superior thermal comfort for the users. The thermal characteristics are derived experimentally by means of a guard ring apparatus under different working temperatures. Tests are performed on the multilayer insulator itself and on a composite structure, made of the multilayer insulator and two air gaps wrapped by a polyester cover, which is the core of a new lightweight emergency architecture. Experimental results show good agreement with literature data, providing a thermal conductivity and transmittance of about 0.04 W/(m °C) and 1.6 W/(m 2 °C) for the tested multilayer. The composite structure called Thermo Reflective Multilayer System (TRMS) shows better insulation performances, providing a thermal transmittance set to 0.85 W/(m 2 °C). A thermal model of an emergency tent based on the new insulating structure (TRMS) has been developed and its thermal performances have been compared with those of a UNHCR traditional emergency shelter. The shelter model was simulated (Trnsys v.17 environment) in the winter season considering the climate of Belgrade and using only the casual gains from occupant and solar radiation through opaque wall. Numerical simulations evidenced that the new insulating composite envelope reduces required heating load of about two and four times with respect to the traditional insulation. The study sets a starting point to develop a lightweight emergency architecture made with a combination between multilayer, air, polyester and vulcanized rubber. - Highlights: • Multilayer insulator tested by means of a guard ring apparatus. • Thermo reflective multilayer system (TRMS) development
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Soft Magnetic Multilayered Thin Films for HF Applications
Loizos, George; Giannopoulos, George; Serletis, Christos; Maity, Tuhin; Roy, Saibal; Lupu, Nicoleta; Kijima, Hanae; Yamaguchi, Masahiro; Niarchos, Dimitris
Multilayered thin films from various soft magnetic materials were successfully prepared by magnetron sputtering in Ar atmosphere. The magnetic properties and microstructure were investigated. It is found that the films show good soft magnetic properties: magnetic coercivity of 1-10 Oe and saturation magnetization higher than 1T. The initial permeability of the films is greater than 300 and flattens up to 600 MHz. The multilayer thin film properties in combination with their easy, fast and reproducible fabrication indicate that they are potential candidates for high frequency applications.
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Negative Refraction Using Frequency-Tuned Oxide Multilayer Structure
Directory of Open Access Journals (Sweden)
Yalin Lu
2008-01-01
Full Text Available An oxide-based multilayer structure was proposed to realize negative refraction. The multilayer composes of alternative layers having negative permittivity and negative permeability, respectively. In order to realize negative refraction, their dielectric and magnetic resonances of layers will be tuned to the frequency as close as possibly via changing their temperature, composition, structure, and so forth. Such oxide-based NIMs are attractive for their potential applications as optical super lenses, imagers, optical cloaking, sensors, and so forth, those are required with low-loss, low-cost, and good fabrication flexibility.
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Room temperature fatigue behavior of OFHC copper and CuAl25 specimens of two sizes
DEFF Research Database (Denmark)
Singhal, A.; Stubbins, J.F.; Singh, B.N.
1994-01-01
requiring an understanding of their fatigue behavior.This paper describes the room temperature fatigue behavior of unirradiated OFHC (oxygen-free high-conductivity) copper and CuAl25 (copper strengthened with a 0.25% atom fraction dispersion of alumina). The response of two fatigue specimen sizes to strain......Copper and its alloys are appealing for application in fusion reactor systems for high heat flux components where high thermal conductivities are critical, for instance, in divertor components. The thermal and mechanical loading of such components will be, at least in part, cyclic in nature, thus...
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Multilayer DNA Origami Packed on Hexagonal and Hybrid Lattices
Ke, Yonggang; Voigt, Niels V.; Gothelf, Kurt V.; Shih, William M.
2012-01-01
“Scaffolded DNA origami” has been proven to be a powerful and efficient approach to construct two-dimensional or three-dimensional objects with great complexity. Multilayer DNA origami has been demonstrated with helices packing along either honeycomb-lattice geometry or square-lattice geometry. Here we report successful folding of multilayer DNA origami with helices arranged on a close-packed hexagonal lattice. This arrangement yields a higher density of helical packing and therefore higher r...
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2011-01-03
... DEPARTMENT OF COMMERCE International Trade Administration [C-570-971] Multilayered Wood Flooring... Department'') initiated an investigation of multilayered wood flooring from the People's Republic of China (``PRC''). See Multilayered Wood Flooring From the People's Republic of China: Initiation of...
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Thermoelasticity and interdiffusion in CuNi multilayers
International Nuclear Information System (INIS)
Benoudia, M.C.; Gao, F.; Roussel, J.M.; Labat, S.; Gailhanou, M.; Thomas, O.; Beke, D.L.; Erdelyi, Z.; Langer, G.A.; Csik, A.; Kis-Varga, M.
2012-01-01
Complete text of publication follows. The idea of observing artificial metallic multilayers with x-ray diffraction techniques to study interdiffusion phenomena dates back to the work of DuMond and Youtz. Interestingly, these pioneering contributions even suggested that the approach could be used to measure the concentration dependence of the diffusion coefficient. This remark is precisely the subject of the present work: we aim to revisit this issue in light of recent atomistic simulation results obtained for coherent CuNi multilayers. More generally, CuNi multilayers have been extensively studied for their magnetic, mechanical, and optical properties. These physical properties depend critically on interfaces and require a good control on the evolution of composition and strain fields under heat treatment. Understanding of how interdiffusion proceeds in these nanosystems should therefore improve these practical aspects. From a theoretical viewpoint these synthetic modulated structures have been also used as valuable model systems to test the various diffusion theories accounting in particular for the influence of the alloying energy, the coherency strain, and the local concentration. Nowadays, this field remains active and has been extended with the development of atomic simulations and many microscopy techniques like atom probe tomography which give details on the intermixing mechanisms. We have performed x-ray diffraction experiments on coherent CuNi multilayers to probe thermoelasticity and interdiffusion in these samples. Kinetic mean-field simulations combined with the modeling of the x-ray spectra were also achieved to rationalize the experimental results. We have shown that classical thermoelastic arguments combined with bulk data can be used to model the x-ray scattered intensity of annealed coherent CuNi multilayers. This result provides a valuable framework to analyze the evolution of the concentration profiles at higher temperature. The typical coherent
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Design guidelines for advanced LSI microcircuit packaging using thick film multilayer technology
Peckinpaugh, C. J.
1974-01-01
Ceramic multilayer circuitry results from the sequential build-up of two or more layers of pre-determined conductive interconnections separated by dielectric layers and fired at an elevated temperature to form a solidly fused structure. The resultant ceramic interconnect matrix is used as a base to mount active and passive devices and provide the necessary electrical interconnection to accomplish the desired electrical circuit. Many methods are known for developing multilevel conductor mechanisms such as multilayer printed circuits, welded wire matrices, flexible copper tape conductors, and thin and thick-film ceramic multilayers. Each method can be considered as a specialized field with each possessing its own particular set of benefits and problems. This design guide restricts itself to the art of design, fabrication and assembly of ceramic multilayer circuitry and the reliability of the end product.
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Kossel interferences of proton-induced X-ray emission lines in periodic multilayers
Energy Technology Data Exchange (ETDEWEB)
Wu, Meiyi; Le Guen, Karine; André, Jean-Michel [Sorbonne Universités, UPMC Univ Paris 06, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); CNRS UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); Ilakovac, Vita [Sorbonne Universités, UPMC Univ Paris 06, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); CNRS UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, 11 rue Pierre et Marie Curie, F-75231 Paris cedex 05 (France); Université de Cergy-Pontoise, F-95031 Cergy-Pontoise (France); Vickridge, Ian [Sorbonne Universités, UPMC Univ Paris 06, Institut des NanoSciences de Paris, 4 place Jussieu, boîte courrier 840, F-75252 Paris cedex 05 (France); CNRS UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, boîte courrier 840, F-75252 Paris cedex 05 (France); Schmaus, Didier [Sorbonne Universités, UPMC Univ Paris 06, Institut des NanoSciences de Paris, 4 place Jussieu, boîte courrier 840, F-75252 Paris cedex 05 (France); CNRS UMR 7588, Institut des NanoSciences de Paris, 4 place Jussieu, boîte courrier 840, F-75252 Paris cedex 05 (France); Université Paris Diderot-P7, F-75205 Paris cedex 13 (France); and others
2016-11-01
The Kossel interferences generated by characteristic X-ray lines produced inside a periodic multilayer have been observed upon proton irradiation, by submitting a Cr/B{sub 4}C/Sc multilayer stack to 2 MeV protons and observing the intensity of the Sc and Cr Kα characteristic emissions as a function of the detection angle. When this angle is close to the Bragg angle corresponding to the emission wavelength and period of the multilayer, an oscillation of the measured intensity is detected. The results are in good agreement with a model based on the reciprocity theorem. The combination of the Kossel measurements and their simulation, will be a useful tool to obtain a good description of the multilayer stack and thus to study nanometer-thick layers and their interfaces.
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Electrical resistivity of thin metal films and multilayers
International Nuclear Information System (INIS)
Fenn, M.
1999-01-01
The electrical resistivity and temperature coefficient of resistivity (TCR) of thin films and multilayers of Cu, Nb and Zr have been measured over a wide range of layer thicknesses. The structure of the films has been characterised using transmission electron microscopy (TEM) and x-ray reflectivity. The experimental results have been compared with the semiclassical theory due to Dimmich. The values of the grain boundary reflectivity, R, in the single films has been found to be approximately 0.35 for Cu in agreement with the literature. The value of R for Nb and Zr has been found to vary with grain size, although it is approximately 0.55 for Nb and 0.925 for Zr over a wide range of grain sizes, and this is believed to be presented for the first time. The value of the interfacial specularity parameter, p, is not found to have a significant effect compared to R in the single films. Dimmich's theoretical expression for the TCR does not match experiment, but by adapting the resistivity expression of the theory to different temperatures a satisfactory fit has been obtained. It has been concluded that the assumption of the free electron model in the presence of grain boundary scattering is in error. The adapted theory predicts negative TCR in sufficiently thin films with experimentally plausible values of the input parameters, and this is believed to be demonstrated for the first time. The experimental resistivity of the multilayers was much lower than expected from the resistivity of the single films. A theoretical fit to the experimental resistivity and TCR of the multilayers was obtained by adjusting the parameter values obtained from single films, and the value of p was found to be significant. This procedure leads to a contradiction in the value of R for Nb. With a view to extending the above work to magnetic multilayers, an AC susceptometer has been designed, built and tested. The results indicate that this instrument would be suitable for work on magnetic
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Energy Technology Data Exchange (ETDEWEB)
Sen, Seema, E-mail: seema.sen@tu-ilmenau.de [Technical University of Ilmenau, Department of Materials for Electronics, Gustav-Kirchhoff-Str. 5, 98693 Ilmenau (Germany); Niederrhein University of Applied Science, Department of Mechanical and Process Engineering, Reinarzstraße 49, 47805 Krefeld (Germany); Lake, Markus; Kroppen, Norman; Farber, Peter; Wilden, Johannes [Niederrhein University of Applied Science, Department of Mechanical and Process Engineering, Reinarzstraße 49, 47805 Krefeld (Germany); Schaaf, Peter [Technical University of Ilmenau, Department of Materials for Electronics, Gustav-Kirchhoff-Str. 5, 98693 Ilmenau (Germany)
2017-02-28
Highlights: • Development of nanoscale Ti/Al multilayer films with 1:1, 1:2 and 1:3 molar ratios. • Characterization of exothermic reaction propagation by experiments and simulation. • The reaction velocity depends on the ignition potentials and molar ratios of the films. • Only 1Ti/3Al films exhibit the unsteady reaction propagation with ripple formation. • CFD simulation shows the time dependent atom mixing and temperature flow during exothermic reaction. - Abstract: This study describes the self-propagating exothermic reaction in Ti/Al reactive multilayer foils by using experiments and computational fluid dynamics simulation. The Ti/Al foils with different molar ratios of 1Ti/1Al, 1Ti/2Al and 1Ti/3Al were fabricated by magnetron sputtering method. Microstructural characteristics of the unreacted and reacted foils were analyzed by using electronic and atomic force microscopes. After an electrical ignition, the influence of ignition potentials on reaction propagation has been experimentally investigated. The reaction front propagates with a velocity of minimum 0.68 ± 0.4 m/s and maximum 2.57 ± 0.6 m/s depending on the input ignition potentials and the chemical compositions. Here, the 1Ti/3Al reactive foil exhibits both steady state and unsteady wavelike reaction propagation. Moreover, the numerical computational fluid dynamics (CFD) simulation shows the time dependent temperature flow and atomic mixing in a nanoscale reaction zone. The CFD simulation also indicates the potentiality for simulating exothermic reaction in the nanoscale Ti/Al foil.
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Interface characterization in B-based multilayer mirrors for next generation lithography
International Nuclear Information System (INIS)
Naujok, Philipp; Yulin, Sergiy; Müller, Robert; Kaiser, Norbert; Tünnermann, Andreas
2016-01-01
The interfaces in La/B_4C and LaN/B_4C multilayer mirrors designed for near normal incidence reflection of 6.x nm EUV light were investigated by grazing incidence X-ray reflectometry, high-resolution transmission electron microscopy and EUV reflectometry. The thickness and roughness asymmetries of the different interfaces in both studied systems have been identified. A development of interface roughness with an increasing number of bilayers was found by different investigation methods. For near normal incidence, R = 51.1% @ λ = 6.65 nm could be reached with our La/B_4C multilayer mirrors, whereas R = 58.1% was achieved with LaN/B_4C multilayers at the same wavelength. - Highlights: • Interface structure in B-based multilayer mirrors investigated. • Combining X-ray reflection, EUV reflection and transmission electron microscopy • Interface thickness and roughness asymmetry identified • Interface roughness increases with higher number of bilayers.
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Performance Test of the Microwave Ion Source with the Multi-layer DC Break
International Nuclear Information System (INIS)
Kim, Dae Il; Kwon, Hyeok Jung; Kim, Han Sung; Seol, Kyung Tae; Cho, Yong Sub
2012-01-01
A microwave proton source has been developed as a proton injector for the 100-MeV proton linac of the PEFP (Proton Engineering Frontier Project). On microwave ion source, the high voltage for the beam extraction is applied to the plasma chamber, also to the microwave components such as a 2.45GHz magnetron, a 3-stub tuner, waveguides. If microwave components can be installed on ground side, the microwave ion source can be operated and maintained easily. For the purpose, the multi-layer DC break has been developed. A multi-layer insulation has the arrangement of conductors and insulators as shown in the Fig. 1. For the purpose of stable operation as the multi-layer DC break, we checked the radiation of the insulator depending on materials and high voltage test of a fabricated multi-layer insulation. In this report, the details of performance test of the multi-layer DC break will be presented
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The calculation of electron depth-dose distributions in multilayer medium
International Nuclear Information System (INIS)
Wang Chuanshan; Xu Mengjie; Li Zhiliang; Feng Yongxiang; Li Panlin
1989-01-01
Energy deposition in multilayer medium and the depth dose distribution in the layers are studied. Based on semi-empirical calculation of electron energy absorption in matter with EDMULT program of Tabata and Ito, further work has been carried out to extend the computation to multilayer composite material. New program developed in this paper makes IBM-PC compatible with complicated electron dose calculations
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Processing and characterization of multilayers for energy device fabrication (invited)
DEFF Research Database (Denmark)
Kaiser, Andreas; Kiebach, Wolff-Ragnar; Gurauskis, Jonas
SOFC and tubular OTM, we present selected challenges in ceramic processing such asymmetric multilayer structures. By optimizing different steps in the ceramic processing, we improved the mechanical properties and gas permeability of porous supports and the (electrochemical) performance of electrodes......The performance of asymmetric multilayer structures in solid oxide fuel cells (SOFC)/solid oxide electrolysis cells (SOEC), tubular oxygen transport membranes (OTM) and similar high temperature energy devices is often determined by the ceramic fabrication (for given materials and design). A good...... understanding and control of different processing steps (from powder/materials selection, through shaping and sintering) is of crucial importance to achieve a defect-free multilayer microstructure with the desired properties and performance. Based on the experiences at DTU Energy with the fabrication of planar...
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Interface alloying in multilayer thin films using polarized neutron reflectometry
International Nuclear Information System (INIS)
Basu, Saibal
2013-01-01
Polarized Neutron Reflectometry (PNR) is an excellent tool to probe magnetic depth profile in multilayer thin film samples. In case of multilayer films with alternating magnetic and non-magnetic layers, PNR can provide magnetic depth profile at the interfaces with better than nanometer resolution. Using PNR and Xray Reflectometry (XRR) together one can obtain chemical composition and magnetic structure, viz. magnetic moment density at interfaces in multilayer films. We have used these two techniques to obtain kinetics of alloy formation at the interfaces and the magnetic nature of the alloy at the interfaces in several important thin films with magnetic/non-magnetic bilayers. These include Ni/Ti, Ni/Al and Si/Ni pairs. Results obtained from these studies will be presented in this talk. (author)
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Lamellar multilayer hexadecylaniline-modified gold nanoparticle ...
Indian Academy of Sciences (India)
standard Wilhelmy plate was used for surface pressure sensing. Multilayer ... carried out on a JEOL model 1200EX instrument operated at an accelerating voltage of ... the gold nanoparticles within domains (and reorganization of the domains ...
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Li, L. L.; Partoens, B.; Peeters, F. M.
2018-04-01
By taking account of the electric-field-induced charge screening, a self-consistent calculation within the framework of the tight-binding approach is employed to obtain the electronic band structure of gated multilayer phosphorene and the charge densities on the different phosphorene layers. We find charge density and screening anomalies in single-gated multilayer phosphorene and electron-hole bilayers in dual-gated multilayer phosphorene. Due to the unique puckered lattice structure, both intralayer and interlayer charge screenings are important in gated multilayer phosphorene. We find that the electric-field tuning of the band structure of multilayer phosphorene is distinctively different in the presence and absence of charge screening. For instance, it is shown that the unscreened band gap of multilayer phosphorene decreases dramatically with increasing electric-field strength. However, in the presence of charge screening, the magnitude of this band-gap decrease is significantly reduced and the reduction depends strongly on the number of phosphorene layers. Our theoretical results of the band-gap tuning are compared with recent experiments and good agreement is found.
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2011-12-08
..., tongue-and-groove construction or locking joints). All multilayered wood flooring is included within the... DEPARTMENT OF COMMERCE International Trade Administration [C-570-971] Multilayered Wood Flooring...''), the Department is issuing a countervailing duty (``CVD'') order on multilayered wood flooring from the...
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Grazing incidence Fe-line telescopes using W/B4C multilayers
DEFF Research Database (Denmark)
Joensen, K. D.; Gorenstein, P.; Christensen, Finn Erland
1995-01-01
The loss of throughput observed at higher energies for traditional grazing-incidence X-ray telescopes coated with high-Z elements can be partly countered by employing multilayers on the outermost reflectors. Using 8-keV reflectivity data from a periodic W/B4C multilayer, the expected performance...
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Song, Jing; Hempenius, Mark A.; Chung, H.J.; Vancso, Gyula J.
2015-01-01
Nanoelectrochemical patterning of redox responsive organometallic poly(ferrocenylsilane) (PFS) multilayers is demonstrated by electrochemical dip pen lithography (EDPN). Local electrochemical oxidation and Joule heating of PFS multilayers from the tip are considered as relevant mechanisms related to
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Comparison of Mg-based multilayers for solar He II radiation at 30.4 nm wavelength
Energy Technology Data Exchange (ETDEWEB)
Zhu Jingtao; Zhou Sika; Li Haochuan; Huang Qiushi; Wang Zhanshan; Le Guen, Karine; Hu, Min-Hui; Andre, Jean-Michel; Jonnard, Philippe
2010-07-10
Mg-based multilayers, including SiC/Mg, Co/Mg, B4C/Mg, and Si/Mg, are investigated for solar imaging and a He II calibration lamp at a 30.4 nm wavelength. These multilayers were fabricated by a magnetron sputtering method and characterized by x-ray reflection. The reflectivities of these multilayers were measured by synchrotron radiation. Near-normal-incidence reflectivities of Co/Mg and SiC/Mg multilayer mirrors are as high as 40.3% and 44.6%, respectively, while those of B4C/Mg and Si/Mg mirrors are too low for application. The measured results suggest that SiC/Mg, Co/Mg multilayers are promising for a 30.4 nm wavelength.
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Energy Technology Data Exchange (ETDEWEB)
Chang, Tien-Li, E-mail: tlchang@ntnu.edu.tw; Chen, Zhao-Chi
2015-12-30
Graphical abstract: - Highlights: • Direct UV laser irradiation on multilayer graphene was discussed. • Multilayer graphene with screen-printed process was presented. • Surface patterning of multilayer graphene at fluence threshold was investigated. • Electrical response of glucose in sensing devices can be studied. - Abstract: The study presents a direct process for surface patterning of multilayer graphene on the glass substrate as a biosensing device. In contrast to lithography with etching, the proposed process provides simultaneous surface patterning of multilayer graphene through nanosecond laser irradiation. In this study, the multilayer graphene was prepared by a screen printing process. Additionally, the wavelength of the laser beam was 355 nm. To perform the effective laser process with the small heat affected zone, the surface patterns on the sensing devices could be directly fabricated using the laser with optimal control of the pulse overlap at a fluence threshold of 0.63 J/cm{sup 2}. The unique patterning of the laser-ablated surface exhibits their electrical and hydrophilic characteristics. The hydrophilic surface of graphene-based sensing devices was achieved in the process with the pulse overlap of 90%. Furthermore, the sensing devices for controlling the electrical response of glucose by using glucose oxidase can be used in sensors in commercial medical applications.
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Simple electrodepositing of CoFe/Cu multilayers: Effect of ferromagnetic layer thicknesses
Energy Technology Data Exchange (ETDEWEB)
Tekgül, Atakan, E-mail: atakantekgul@gmail.com [Akdeniz University, Physics Department, Science Faculty, TR-07058 Antalya (Turkey); Uludag University, Physics Department, Science and Literature Faculty, TR-16059 Bursa (Turkey); Alper, Mürsel [Uludag University, Physics Department, Science and Literature Faculty, TR-16059 Bursa (Turkey); Kockar, Hakan [Balikesir University, Physics Department, Science and Literature Faculty, TR-10145 Balikesir (Turkey)
2017-01-01
The CoFe/Cu magnetic multilayers were produced by changing CoFe ferromagnetic layers from 3 nm to 10 nm using electrodeposition. By now, the thinnest Cu (0.5 nm) layer thicknesses were used to see whether the GMR effect in the multilayers can be obtained or not since the pinning of non-magnetic layer between the ferromagnetic layers is required. For the proper depositions, the cyclic voltammograms was used, and the current–time transients were obtained. The Cu and CoFe layers were deposited at a cathode potential of −0.3 and −1.5 V with respect to saturated calomel electrode, respectively. From the XRD patterns, the multilayers were shown to be fcc crystal structures. For the magnetization measurements, saturation magnetization increases from 160 to 600 kA/m from 3 to 8 nm ferromagnetic layer thicknesses. And, the coercivity values increase until the 8 nm of the CoFe layer thickness. It is seen that the thin Cu layer (fixed at 0.5 nm) and pinholes support the random magnetization orientation and thus all multilayers exhibited the giant magnetoresistance (GMR) effect, and the highest GMR value was observed about 5.5%. And, the variation of GMR field sensitivity was calculated. The results show that the GMR and GMR sensitivity are compatible among the multilayers. The CoFe/Cu magnetic multilayers having GMR properties are used in GMR sensors and hard disk drive of the nano-technological devices. - Highlights: • The much thinner (0.5 nm) Cu layer was used to obtain the GMR effect on the electrodeposited CoFe/Cu multilayers. • All samples exhibited GMR and the maximum GMR value was 5.5%. • The M{sub s} and the H{sub c} changed with increasing magnetic layer thickness.
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2012-02-03
..., tongue-and-groove construction or locking joints). All multilayered wood flooring is included within the... DEPARTMENT OF COMMERCE International Trade Administration [A-570-970, C-570-971] Multilayered Wood... (``CVD'') orders on multilayered wood flooring from the People's Republic of China (``PRC'') to remove an...
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Overview of the CERES Edition-4 Multilayer Cloud Property Datasets
Chang, F. L.; Minnis, P.; Sun-Mack, S.; Chen, Y.; Smith, R. A.; Brown, R. R.
2014-12-01
Knowledge of the cloud vertical distribution is important for understanding the role of clouds on earth's radiation budget and climate change. Since high-level cirrus clouds with low emission temperatures and small optical depths can provide a positive feedback to a climate system and low-level stratus clouds with high emission temperatures and large optical depths can provide a negative feedback effect, the retrieval of multilayer cloud properties using satellite observations, like Terra and Aqua MODIS, is critically important for a variety of cloud and climate applications. For the objective of the Clouds and the Earth's Radiant Energy System (CERES), new algorithms have been developed using Terra and Aqua MODIS data to allow separate retrievals of cirrus and stratus cloud properties when the two dominant cloud types are simultaneously present in a multilayer system. In this paper, we will present an overview of the new CERES Edition-4 multilayer cloud property datasets derived from Terra as well as Aqua. Assessment of the new CERES multilayer cloud datasets will include high-level cirrus and low-level stratus cloud heights, pressures, and temperatures as well as their optical depths, emissivities, and microphysical properties.
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Photon wavelength dependent valley photocurrent in multilayer MoS2
Guan, Hongming; Tang, Ning; Xu, Xiaolong; Shang, LiangLiang; Huang, Wei; Fu, Lei; Fang, Xianfa; Yu, Jiachen; Zhang, Caifeng; Zhang, Xiaoyue; Dai, Lun; Chen, Yonghai; Ge, Weikun; Shen, Bo
2017-12-01
The degree of freedom (DOF) of the K (K') valley in transition-metal dichalcogenides, especially molybdenum disulfide (MoS2), offers an opportunity for next-generation valleytronics devices. In this work, the K (K') valley DOF of multilayer MoS2 is studied by means of the photon wavelength dependent circular photogalvanic effect (CPGE) at room temperature upon a strong external out-of-plane electric field induced by an ionic liquid (IL) gate, which breaks the spatial-inversion symmetry. It is demonstrated that only on resonant excitations in the K (K') valley can the valley-related CPGE signals in multilayer MoS2 with an IL gate be detected, indicating that the valley contrast is indeed regenerated between the K and K' valleys when the electric field is applied. As expected, it can also be seen that the K (K') valley DOF in multilayer MoS2 can be modulated by the external electric field. The observation of photon wavelength dependent valley photocurrent in multilayer MoS2, with the help of better Ohmic contacts, may pave a way for optoelectronic applications of valleytronics in the future.
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Interlayer growth in Mo/B4C multilayered structures upon thermal annealing
International Nuclear Information System (INIS)
Nyabero, S. L.; Kruijs, R. W. E. van de; Yakshin, A. E.; Zoethout, E.; Bosgra, J.; Loch, R. A.; Blanckenhagen, G. von; Bijkerk, F.
2013-01-01
Both multilayer period thickness expansion and compaction were observed in Mo/B 4 C multilayers upon annealing, and the physical causes for this were explored in detail. Using in situ time-dependent grazing incidence X-ray reflectometry, period changes down to picometer-scale were resolved. It was shown that the changes depend on the thickness of the B 4 C layers, annealing temperature, and annealing time. Although strong stress relaxation during annealing was observed, it was excluded as a cause for period expansion. Auger electron spectroscopy and wide angle X-ray diffraction measurements revealed the growth of interlayers, with associated period changes influenced by the supply of B and C atoms to the growing compound interlayers. For multilayers with a Mo thickness of 3 nm, two regimes were recognized, depending on the deposited B 4 C thickness: in multilayers with B 4 C ≤ 1.5 nm, the supply of additional Mo into the already formed MoB x C y interlayer was dominant and led to densification, resulting in period compaction. For multilayers with B 4 C ≥ 2 nm, the B and C enrichment of interlayers formed low density compounds and yielded period expansion.
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[The role of BCP in electroluminescence of multilayer organic light-emitting devices].
Deng, Zhao-Ru; Yang, Sheng-Yi; Lou, Zhi-Dong; Meng, Ling-Chuan
2009-03-01
As a hole-blocking layer, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) is usually used in blue and white light electroluminescent devices. The ability of blocking holes of BCP layer depends on its thickness, and basically holes can tunnel through thin BCP layer. In order to know the role of BCP layer in electroluminescence (EL) of multilayer organic light-emitting diodes (OLEDs), in the present paper, the authors designed a multilayer OLED ITO/NPB/BCP/Alq3 : DCJTB/Alq3/Al and investigated the influence of thickness of BCP on the EL spectra of multilayer OLEDs at different applied voltages. The experimental data show that thin BCP layer can block holes partially and tune the energy transfer between different emissive layers, and in this way, it is easy to obtain white emission, but its EL spectra will change with the applied voltages. The EL spectra of multilayer device will remain relatively stable when BCP layer is thick enough, and the holes can hardly tunnel through when the thickness of BCP layer is more than 15 nm. Furthermore, the stability of EL spectra of the multilayer OLED at different applied voltages was discussed.
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Direct Magnetic Relief Recording Using As40S60: Mn-Se Nanocomposite Multilayer Structures.
Stronski, A; Achimova, E; Paiuk, O; Meshalkin, A; Prisacar, A; Triduh, G; Oleksenko, P; Lytvyn, P
2017-12-01
Processes of holographic recording of surface relief structures using As 2 S 3 :Mn-Se multilayer nanostructures as registering media were studied in this paper. Optical properties of As 2 S 3 :Mn, Se layers, and As 2 S 3 :Mn-Se multilayer nanostructures were investigated. Values of optical bandgaps were obtained from Tauc dependencies. Surface relief diffraction gratings were recorded. Direct one-stage formation of surface relief using multilayer nanostructures is considered. For the first time, possibility of direct formation of magnetic relief simultaneous with surface relief formation under optical recording using As 2 S 3 :Mn-Se multilayer nanostructures is shown.
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Structural color of a lycaenid butterfly: analysis of an aperiodic multilayer structure
International Nuclear Information System (INIS)
Yoshioka, S; Shimizu, Y; Kinoshita, S; Matsuhana, B
2013-01-01
We investigated the structural color of the green wing of the lycaenid butterfly Chrysozephyrus brillantinus. Electron microscopy revealed that the bottom plate of the cover scale on the wing consists of an alternating air–cuticle multilayer structure. However, the thicknesses of the layers were not constant but greatly differed depending on the layer, unlike the periodic multilayer designs often adopted for artificial laser-reflecting mirrors. The agreement between the experimentally determined and theoretically calculated reflectance spectra led us to conclude that the multilayer interference in the aperiodic system is the primary origin of the structural color. We analyzed optical interference in this aperiodic system using a simple analytical model and found that two spectral peaks arise from constructive interference among different parts of the multilayer structure. We discuss the advantages and disadvantages of the aperiodic system over a periodic one. (paper)
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Dynamics of confined reactive water in smectite clay-zeolite composites.
Pitman, Michael C; van Duin, Adri C T
2012-02-15
The dynamics of water confined to mesoporous regions in minerals such as swelling clays and zeolites is fundamental to a wide range of resource management issues impacting many processes on a global scale, including radioactive waste containment, desalination, and enhanced oil recovery. Large-scale atomic models of freely diffusing multilayer smectite particles at low hydration confined in a silicalite cage are used to investigate water dynamics in the composite environment with the ReaxFF reactive force field over a temperature range of 300-647 K. The reactive capability of the force field enabled a range of relevant surface chemistry to emerge, including acid/base equilibria in the interlayer calcium hydrates and silanol formation on the edges of the clay and inner surface of the zeolite housing. After annealing, the resulting clay models exhibit both mono- and bilayer hydration structures. Clay surface hydration redistributed markedly and yielded to silicalite water loading. We find that the absolute rates and temperature dependence of water dynamics compare well to neutron scattering data and pulse field gradient measures from relevant samples of Ca-montmorillonite and silicalite, respectively. Within an atomistic, reactive context, our results distinguish water dynamics in the interlayer Ca(OH)(2)·nH(2)O environment from water flowing over the clay surface, and from water diffusing within silicalite. We find that the diffusion of water when complexed to Ca hydrates is considerably slower than freely diffusing water over the clay surface, and the reduced mobility is well described by a difference in the Arrhenius pre-exponential factor rather than a change in activation energy.
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Automation Enhancement of Multilayer Laue Lenses
Energy Technology Data Exchange (ETDEWEB)
Lauer K. R.; Conley R.
2010-12-01
X-ray optics fabrication at Brookhaven National Laboratory has been facilitated by a new, state of the art magnetron sputtering physical deposition system. With its nine magnetron sputtering cathodes and substrate carrier that moves on a linear rail via a UHV brushless linear servo motor, the system is capable of accurately depositing the many thousands of layers necessary for multilayer Laue lenses. I have engineered a versatile and automated control program from scratch for the base system and many subsystems. Its main features include a custom scripting language, a fully customizable graphical user interface, wireless and remote control, and a terminal-based interface. This control system has already been successfully used in the creation of many types of x-ray optics, including several thousand layer multilayer Laue lenses.Before reaching the point at which a deposition can be run, stencil-like masks for the sputtering cathodes must be created to ensure the proper distribution of sputtered atoms. Quality of multilayer Laue lenses can also be difficult to measure, given the size of the thin film layers. I employ my knowledge of software and algorithms to further ease these previously painstaking processes with custom programs. Additionally, I will give an overview of an x-ray optic simulator package I helped develop during the summer of 2010. In the interest of keeping my software free and open, I have worked mostly with the multiplatform Python and the PyQt application framework, utilizing C and C++ where necessary.
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High efficiency multilayer blazed gratings for EUV and soft X-rays: Recent developments
International Nuclear Information System (INIS)
Voronov, Dmitriy; Ahn, Minseung; Anderson, Erik; Cambie, Rossana; Chang, Chih-Hao; Goray, Leonid; Gullikson, Eric; Heilmann, Ralf; Salmassi, Farhad; Schattenburg, Mark; Warwick, Tony; Yashchuk, Valeriy; Padmore, Howard
2011-01-01
Multilayer coated blazed gratings with high groove density are the best candidates for use in high resolution EUV and soft x-ray spectroscopy. Theoretical analysis shows that such a grating can be potentially optimized for high dispersion and spectral resolution in a desired high diffraction order without significant loss of diffraction efficiency. In order to realize this potential, the grating fabrication process should provide a perfect triangular groove profile and an extremely smooth surface of the blazed facets. Here we report on recent progress achieved at the Advanced Light Source (ALS) in fabrication of high quality multilayer coated blazed gratings. The blazed gratings were fabricated using scanning beam interference lithography followed by wet anisotropic etching of silicon. A 200 nm period grating coated with a Mo/Si multilayer composed with 30 bi-layers demonstrated an absolute efficiency of 37.6percent in the 3rd diffraction order at 13.6 nm wavelength. The groove profile of the grating was thoroughly characterized with atomic force microscopy before and after the multilayer deposition. The obtained metrology data were used for simulation of the grating efficiency with the vector electromagnetic PCGrate-6.1 code. The simulations showed that smoothing of the grating profile during the multilayer deposition is the main reason for efficiency losses compared to the theoretical maximum. Investigation of the grating with cross-sectional transmission electron microscopy revealed a complex evolution of the groove profile in the course of the multilayer deposition. Impact of the shadowing and smoothing processes on growth of the multilayer on the surface of the sawtooth substrate is discussed.
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Evolutionary games on multilayer networks: a colloquium
Wang, Zhen; Wang, Lin; Szolnoki, Attila; Perc, Matjaž
2015-05-01
Networks form the backbone of many complex systems, ranging from the Internet to human societies. Accordingly, not only is the range of our interactions limited and thus best described and modeled by networks, it is also a fact that the networks that are an integral part of such models are often interdependent or even interconnected. Networks of networks or multilayer networks are therefore a more apt description of social systems. This colloquium is devoted to evolutionary games on multilayer networks, and in particular to the evolution of cooperation as one of the main pillars of modern human societies. We first give an overview of the most significant conceptual differences between single-layer and multilayer networks, and we provide basic definitions and a classification of the most commonly used terms. Subsequently, we review fascinating and counterintuitive evolutionary outcomes that emerge due to different types of interdependencies between otherwise independent populations. The focus is on coupling through the utilities of players, through the flow of information, as well as through the popularity of different strategies on different network layers. The colloquium highlights the importance of pattern formation and collective behavior for the promotion of cooperation under adverse conditions, as well as the synergies between network science and evolutionary game theory.
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Pang, Linyong; Hu, Peter; Satake, Masaki; Tolani, Vikram; Peng, Danping; Li, Ying; Chen, Dongxue
2011-11-01
According to the ITRS roadmap, mask defects are among the top technical challenges to introduce extreme ultraviolet (EUV) lithography into production. Making a multilayer defect-free extreme ultraviolet (EUV) blank is not possible today, and is unlikely to happen in the next few years. This means that EUV must work with multilayer defects present on the mask. The method proposed by Luminescent is to compensate effects of multilayer defects on images by modifying the absorber patterns. The effect of a multilayer defect is to distort the images of adjacent absorber patterns. Although the defect cannot be repaired, the images may be restored to their desired targets by changing the absorber patterns. This method was first introduced in our paper at BACUS 2010, which described a simple pixel-based compensation algorithm using a fast multilayer model. The fast model made it possible to complete the compensation calculations in seconds, instead of days or weeks required for rigorous Finite Domain Time Difference (FDTD) simulations. Our SPIE 2011 paper introduced an advanced compensation algorithm using the Level Set Method for 2D absorber patterns. In this paper the method is extended to consider process window, and allow repair tool constraints, such as permitting etching but not deposition. The multilayer defect growth model is also enhanced so that the multilayer defect can be "inverted", or recovered from the top layer profile using a calibrated model.
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Exploring interface morphology of a deeply buried layer in periodic multilayer
Energy Technology Data Exchange (ETDEWEB)
Das, Gangadhar; Srivastava, A. K.; Tiwari, M. K., E-mail: mktiwari@rrcat.gov.in [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore-452013, Madhya Pradesh (India); Homi Bhabha National Institute, Anushaktinagar, Mumbai-400094, Maharashtra (India); Khooha, Ajay; Singh, A. K. [Indus Synchrotrons Utilization Division, Raja Ramanna Centre for Advanced Technology, Indore-452013, Madhya Pradesh (India)
2016-06-27
Long-term durability of a thin film device is strongly correlated with the nature of interface structure associated between different constituent layers. Synthetic periodic multilayer structures are primarily employed as artificial X-ray Bragg reflectors in many applications, and their reflection efficiency is predominantly dictated by the nature of the buried interfaces between the different layers. Herein, we demonstrate the applicability of the combined analysis approach of the X-ray reflectivity and grazing incidence X-ray fluorescence measurements for the reliable and precise determination of a buried interface structure inside periodic X-ray multilayer structures. X-ray standing wave field (XSW) generated under Bragg reflection condition is used to probe the different constituent layers of the W- B{sub 4}C multilayer structure at 10 keV and 12 keV incident X-ray energies. Our results show that the XSW assisted fluorescence measurements are markedly sensitive to the location and interface morphology of a buried layer structure inside a periodic multilayer structure. The cross sectional transmission electron microscopy results obtained on the W-B{sub 4}C multilayer structure provide a deeper look on the overall reliability and accuracy of the XSW method. The method described here would also be applicable for nondestructive characterization of a wide range of thin film based semiconductor and optical devices.
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KLASIFIKASI WEBSITE MENGGUNAKAN ALGORITMA MULTILAYER PERCEPTRON
Directory of Open Access Journals (Sweden)
Nyoman Purnama
2014-12-01
Full Text Available Sistem klasifikasi merupakan proses temu balik informasi yang sangat bergantung dari elemen-elemen penyusunnya.Sistem ini banyak digunakan untuk mengatasi permasalahan segmentasi data. Klasifikasi dapat digunakan pada website sebagaimetode untuk mengelompokkan website. Website merupakan salah satu data yang memiliki informasi yang beraneka-ragam,sehingga pengelompokan data ini penting untuk diteliti. Sistem klasifikasi dimulai dengan melakukan proses pengumpulaninformasi dari halaman website (parsing dan untuk setiap hasil parsing dilakukan proses penghapusan kata henti, stemming,feature selection dengan tf-idf. Hasil dari proses ini berupa fitur yang menjadi inputan algoritma Multilayer Perceptron. Dalamalgoritma ini terjadi proses pembelajaran terhadap pola input masukan dan pembuatan bobot pelatihan. Bobot ini akandigunakan pada proses klasifikasi. Hasil dari penelitian menunjukkan bahwa algoritma Multilayer Perceptron dapatmenghasilkan klasifikasi website dengan akurasi yang bagus. Hal ini dibuktikan dengan beberapa tahapan penelitian yangberbeda dan didapatkan nilai akurasi rata-rata diatas 70%.
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Magnetothermoelectric figure of merit of Co/Cu multilayers
Energy Technology Data Exchange (ETDEWEB)
Hu, X. K., E-mail: xiukun.hu@ptb.de; Krzysteczko, P.; Liebing, N.; Schumacher, H. W. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig (Germany); Serrano-Guisan, S. [International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, 4715-330 Braga (Portugal); Rott, K.; Reiss, G. [Fakultät für Physik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld (Germany); Kimling, J.; Böhnert, T.; Nielsch, K. [Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg (Germany)
2014-03-03
The switching of the magnetic configuration of giant magnetoresistance multilayers not only changes the electrical and thermal conductivities but also the thermopower. We study the magnetotransport and the magnetothermoelectric properties of Co/Cu multilayer devices in a lateral thermal gradient. The Seebeck coefficient reaches values up to −18 μV/K at room temperature and shows a magnetic field dependence up to 28.6% upon spin reversal. In combination with thermal conductivity data of the same Co/Cu stack, we find a magnetothermoelectric figure of merit of up to 65%. Furthermore, a magneto-power factor of up to 110% is derived.
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Near-field heat transfer between graphene/hBN multilayers
Zhao, Bo; Guizal, Brahim; Zhang, Zhuomin M.; Fan, Shanhui; Antezza, Mauro
2017-01-01
We study the radiative heat transfer between multilayer structures made by a periodic repetition of a graphene sheet and a hexagonal boron nitride (hBN) slab. Surface plasmons in a monolayer graphene can couple with a hyperbolic phonon polaritons in a single hBN film to form hybrid polaritons that can assist photon tunneling. For periodic multilayer graphene/hBN structures, the stacked metallic/dielectric array can give rise to a further effective hyperbolic behavior, in addition to the intri...
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Magnetic properties and structure of FePt/FeMn multilayers
International Nuclear Information System (INIS)
Phuoc, Nguyen N.; Suzuki, Takao
2007-01-01
A systematic study of the magnetic properties by ion beam sputter-deposition system, was conducted in conjunction with the structure of FePt/FeMn multilayers fabricated onto MgO(0 0 1) substrates. Both parallel and perpendicular exchange biases were observed in the multilayers and were found to decrease drastically, as the deposition temperature is higher than 350 deg. C, which is evidently due to the interdiffusion at the interface. The thickness dependence study shows that the perpendicular magnetic anisotropy observed in the multilayers originates from surface anisotropy, being consistent with the decrease of perpendicular magnetic anisotropy as the deposition temperature is increased. The difference between parallel and perpendicular blocking temperatures that was clearly observed, is possibly due to the spin canting out of plane at the interface
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SIW based multilayer transition and power divider in LTCC technology
Abuzaid, Hattan
2013-06-01
A multilayer transition and balanced power divider are presented for millimeter-wave system-on-package (SoP). These two components operate at Ka-band and exploit the substrate integrate waveguide (SIW) technology with its shielding characteristics and the Low-temperature co-fired ceramics (LTCC) technology for its high density integration. A coupling slot has been used to perform vertical integration, which can be easily optimized through its length. The measured input return loss within the bandwidth of interest (32 GHz-38 GHz) is less than -15 dB and -18 dB for the multilayer transition and the power divider, respectively. The lateral dimensions of a multilayer system, such as a feed network of an array, can be greatly reduced by employing these 3D slot-coupled components. © 2013 IEEE.
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Rohatgi, Aashish; Vecchio, Kenneth S.; Gray, George T.
2001-01-01
The role of stacking fault energy (SFE) in deformation twinning and work hardening was systematically studied in Cu (SFE ˜78 ergs/cm2) and a series of Cu-Al solid-solution alloys (0.2, 2, 4, and 6 wt pct Al with SFE ˜75, 25, 13, and 6 ergs/cm2, respectively). The materials were deformed under quasi-static compression and at strain rates of ˜1000/s in a Split-Hopkinson pressure bar (SHPB). The quasi-static flow curves of annealed 0.2 and 2 wt pct Al alloys were found to be representative of solid-solution strengthening and well described by the Hall-Petch relation. The quasi-static flow curves of annealed 4 and 6 wt pct Al alloys showed additional strengthening at strains greater than 0.10. This additional strengthening was attributed to deformation twins and the presence of twins was confirmed by optical microscopy. The strengthening contribution of deformation twins was incorporated in a modified Hall-Petch equation (using intertwin spacing as the “effective” grain size), and the calculated strength was in agreement with the observed quasi-static flow stresses. While the work-hardening rate of the low SFE Cu-Al alloys was found to be independent of the strain rate, the work-hardening rate of Cu and the high SFE Cu-Al alloys (low Al content) increased with increasing strain rate. The different trends in the dependence of work-hardening rate on strain rate was attributed to the difference in the ease of cross-slip (and, hence, the ease of dynamic recovery) in Cu and Cu-Al alloys.
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International Nuclear Information System (INIS)
Hood, R.Q.
1994-04-01
Utilizing self-consistent Hartree-Fock calculations, several aspects of multilayers and interfaces are explored: enhancement and reduction of the local magnetic moments, magnetic coupling at the interfaces, magnetic arrangements within each film and among non-neighboring films, global symmetry of the systems, frustration, orientation of the various moments with respect to an outside applied field, and magnetic-field induced transitions. Magnetoresistance of ferromagnetic-normal-metal multilayers is found by solving the Boltzmann equation. Results explain the giant negative magnetoresistance encountered in these systems when an initial antiparallel arrangement is changed into a parallel configuration by an external magnetic field. The calculation depends on (1) geometric parameters (thicknesses of layers), (2) intrinsic metal parameters (number of conduction electrons, magnetization, and effective masses in layers), (3) bulk sample properties (conductivity relaxation times), (4) interface scattering properties (diffuse scattering versus potential scattering at the interfaces, and (5) outer surface scattering properties (specular versus diffuse surface scattering). It is found that a large negative magnetoresistance requires considerable asymmetry in interface scattering for the two spin orientations. Features of the interfaces that may produce an asymmetrical spin-dependent scattering are studied: varying interfacial geometric random roughness with no lateral coherence, correlated (quasi-periodic) roughness, and varying chemical composition of the interfaces. The interplay between these aspects of the interfaces may enhance or suppress the magnetoresistance, depending on whether it increases or decreases the asymmetry in the spin-dependent scattering of the conduction electrons
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Multilayer Network Planning - A Practical Perspective
Autenrieth, Achim
2018-01-01
The paper presents a pragmatic and practical multilayer network planning approach based on a candidate lightpath auxiliary graph model. The paper discusses, how this approach can be applied to offline network planning as well as dynamic planning and provisioning of services.
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Biocolloids with ordered urease multilayer shells as enzymatic reactors.
Lvov, Y; Caruso, F
2001-09-01
The preparation of biocolloids with organized enzyme-containing multilayer shells for exploitation as colloidal enzymatic nanoreactors is described. Urease multilayers were assembled onto submicrometer-sized polystyrene spheres by the sequential adsorption of urease and polyelectrolyte, in a predetermined order, utilizing electrostatic interactions for layer growth. The catalytic activity of the biocolloids increased proportionally with the number of urease layers deposited on the particles, demonstrating that biocolloid particles with tailored enzymatic activities can be produced. It was further found that precoating the latex spheres with nanoparticles (40-nm silica or 12-nm magnetite) enhanced both the stability (with respect to adsorption) and enzymatic activity of the urease multilayers. The presence of the magnetite nanoparticle coating also provided a magnetic function that allowed the biocolloids to be easily and rapidly separated with a permanent magnet. The fabrication of such colloids opens new avenues for the application of bioparticles and represents a promising route for the creation of complex catalytic particles.
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Multilayer polymer light-emitting diodes by blade coating method
Tseng, Shin-Rong; Meng, Hsin-Fei; Lee, Kuan-Chen; Horng, Sheng-Fu
2008-10-01
Multilayer polymer light-emitting diodes fabricated by blade coating are presented. Multilayer of polymers can be easily deposited by blade coating on a hot plate. The multilayer structure is confirmed by the total thickness and the cross section view in the scanning electron microscope. The film thickness variation is only 3.3% in 10cm scale and the film roughness is about 0.3nm in the micron scale. The efficiency of single layer poly(para-phenylene vinylene) copolymer Super Yellow and poly(9,9-dioctylfluorene) (PFO, deep blue) devices are 9 and 1.7cd/A, respectively, by blade coating. The efficiency of the PFO device is raised to 2.9cd/A with a 2-(4-tert-butylphenyl)-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD) hole-blocking layer and to 2.3cd/A with a poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)] elec-tron-blocking layer added by blade coating.
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Energy Technology Data Exchange (ETDEWEB)
Xie, Lu [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Yao, Huijun, E-mail: Yaohuijun@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Duan, Jinglai; Chen, Yonghui [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Lyu, Shuangbao [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Maaz, Khan [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Nanomaterials Research Group, Physics Division, PINSTECH, Nilore 45650, Islamabad (Pakistan); Mo, Dan [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Liu, Jie, E-mail: J.Liu@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Sun, Youmei; Hou, Mingdong [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)
2016-12-01
Graphical abstract: The schematic diagram of measurement of extinction spectra of Cu/Ni multilayer nanowire arrays embedded in the template after removing the gold/copper substrate. - Highlights: • The optical properties of Cu/Ni multilayer nanowire arrays were first investigated by UV/Vis/NIR spectrometer and it was confirmed that the extinction peaks strongly related to the periodicity of the multilayer nanowire. • The Ni segment was thought as a kind of impurity which can change the surface electron distribution and thereby the extinction peaks of nanowire. • Current work supplied the clear layer thickness information of Cu and Ni in Cu/Ni multilayer nanowire with TEM and EDS line-scan profile analysis. - Abstract: For understanding the interaction between light and noble/magnetism multilayer nanowires, Cu/Ni multilayer nanowires are fabricated by a multi-potential step deposition technique in etched ion-track polycarbonate template. The component and the corresponding layer thickness of multilayer nanowire are confirmed by TEM and EDS line-scan analysis. By tailoring the nanowire diameter, the Cu layer thickness and the periodicity of the nanowire, the extinction spectral of nanowire arrays exhibit an extra sensitivity to the change of structural parameters. The resonance wavelength caused by surface plasmon resonance increases obviously with increasing the nanowire diameter, the Cu layer thickness and the periodicity. The observations in our work can be explained by the “impurity effect” and coupled effect and can also be optimized for developing optical devices based on multilayer nanowires.
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International Nuclear Information System (INIS)
Xu Zhaoying; Zheng, Y.J.; Jiang, F.; Leng, Y.X.; Sun Hong; Huang Nan
2013-01-01
Highlights: ► The multilayer DLC films with different modulation ratios have been fabricated by FCVA. ► The multilayer DLC films can effectively decrease the residual stress of the DLC films. ► The multilayer DLC film with modulation ratio of 1:1 shows the best wear resistance. - Abstract: The multilayer DLC films consisting of sp 2 -rich DLC layers (soft DLC) and sp 3 -rich DLC layers (hard DLC) with different modulation ratios (thickness ratio of the hard DLC to soft DLC) ranging from 2:1, 1:1 to 1:2 had been deposited on Si (1 0 0) wafer and Ti–6Al–4V alloy substrates by filtered cathodic vacuum arc (FCVA) deposition. The effect of modulation ratio on the microstructure and properties of the multilayer DLC films including sp 3 content, residual stress, mechanical properties, adhesion strength and wear resistance were studied by Raman spectroscopy, profilometry technique, nanoindenter, Vickers indentation test, scanning electron microscopy (SEM) and ball-on-disc reciprocating friction test. The results showed that the sp 3 content and the hardness of the multilayer DLC films decreased with modulation ratios decreasing. The stress of the multilayer DLC films could be effectively reduced and the stress decreased with the modulation ratio decreasing. The multilayer DLC film with modulation ratio of 1:1 had the best wear resistance due to a balance between hardness and residual stress.
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Fabrication of customizable wedged multilayer Laue lenses by adding a stress layer
International Nuclear Information System (INIS)
Niese, Sven; Krüger, Peter; Kubec, Adam; Laas, Roman; Gawlitza, Peter; Melzer, Kathleen; Braun, Stefan; Zschech, Ehrenfried
2014-01-01
Diffractive optics for hard X-rays feature superior properties in terms of resolution and efficiency, if volume diffraction effects are exploited all-over the aperture. For multilayer Laue lenses, preferably a wedged geometry is required to obtain this effect. We present an approach utilizing an additional stress layer to realize the necessary geometrical modifications where each lens can be customized to a selected photon energy independently of the given multilayer deposition. The quality of the deposition of the stress layer is evaluated using a laboratory X-ray microscope prior to its application at synchrotron radiation facilities with a special approach to measure the relative layer tilt at high spatial resolution. - Highlights: • Wedged multilayer Laue lenses were fabricated using an additional stress layer. • Each lens can be customized to any photon energy independently of the multilayer. • The relative layer tilt is measured using laboratory X-ray microscopy
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Molecular dynamics simulation of effects of twin interfaces on Cu/Ni multilayers
International Nuclear Information System (INIS)
Fu, Tao; Peng, Xianghe; Weng, Shayuan; Zhao, Yinbo; Gao, Fengshan; Deng, Lijun; Wang, Zhongchang
2016-01-01
We perform molecular dynamics simulation of the indentation on pure Cu and Ni films and Cu/Ni multilayered films with a cylindrical indenter, aimed to investigate the effects of the cubic-on-cubic interface and hetero-twin interface on their mechanical properties. We also investigate systematically the formation of twin boundary in the pure metals and the effects of the cubic-on-cubic and hetero-twin interface on mechanical properties of the multilayers. We find that the slip of the horizontal stacking fault can release the internal stress, resulting in insignificant strengthening. The change in the crystal orientation by horizontal movement of the atoms in a layer-by-layer manner is found to initiate the movement of twin boundary, and the hetero-twin interface is beneficial to the hardening of multilayers. Moreover, we also find that increasing number of hetero-twin interfaces can harden the Cu/Ni multilayers.
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Role of aluminium concentration on the structure behaviour of Cu-Al alloys
International Nuclear Information System (INIS)
Nassar, A.M.; Taha, A.S.; Ragab, K.A.; El-Mossalamy, S.
1988-06-01
Effect of Al(5, 10, 15 and 20)% on the structure behaviour of Cu-Al alloys was investigated by both microhardness measurements and optical microscopic investigations. Pure Cu was used for comparison. The analysis of the hardness-temperature curve shows a type of dependence which obeys an empirical exponential law, but consists of several distinguishable regions. For Cu 20% Al, one region is observed, and two regions for pure Cu, while for alloys of 5 and 10% Al concentration three regions were observed. The activation energy varies between 0.03 and 0.9 ev. for these regions, depending on the Al-concentration as well as the annealing temperature. The recrystallization temperature was found to increase with increasing Al-concentration. It was also observed that Cu-20% Al alloy is very hard and brittle owing to the formation of γ2 phase, and also to phase separation as being detected from optical microscopic investigations. (author). 22 refs, 3 figs
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Multi-layered, chemically bonded lithium-ion and lithium/air batteries
Narula, Chaitanya Kumar; Nanda, Jagjit; Bischoff, Brian L; Bhave, Ramesh R
2014-05-13
Disclosed are multilayer, porous, thin-layered lithium-ion batteries that include an inorganic separator as a thin layer that is chemically bonded to surfaces of positive and negative electrode layers. Thus, in such disclosed lithium-ion batteries, the electrodes and separator are made to form non-discrete (i.e., integral) thin layers. Also disclosed are methods of fabricating integrally connected, thin, multilayer lithium batteries including lithium-ion and lithium/air batteries.
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Dynamical diffraction in periodic multilayers
Sears, V F
1997-01-01
Exact reflectivity curves are calculated numerically for various periodic multilayers using the optical matrix method in order to test the dynamical theory of diffraction. The theory is generally valid for values of the bilayer thickness d up to about 100 A. For somewhat larger values of d, where the theory begins to break down, the initial discrepancy is in the phase of the oscillations in the wings of the peaks. For very large values of d, where the first-order Bragg peak approaches the edge of the mirror reflection, two general types of multilayers can be distinguished. In the first (typified in the present work by Ni/Ti), there is a large (30% or more) reduction in the actual value of the critical wave vector for total reflection while, in the second (typified here by Fe/Ge), there is very little reduction (3 % or so). The origin of these two very different types of behavior is explained. It is also shown that, within the dynamical theory of diffraction, the change in the position of the center of the Dar...
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2011-12-08
... construction or locking joints). All multilayered wood flooring is included within the definition of the... DEPARTMENT OF COMMERCE International Trade Administration [A-570-970] Multilayered Wood Flooring... is issuing an antidumping duty order on multilayered wood flooring (``wood flooring'') from the...
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Magnetic properties of sputtered Permalloy/molybdenum multilayers
International Nuclear Information System (INIS)
Romera, M.; Ciudad, D.; Maicas, M.; Aroca, C.; Ranchal, R.
2011-01-01
In this work, we report the magnetic properties of sputtered Permalloy (Py: Ni 80 Fe 20 )/molybdenum (Mo) multilayer thin films. We show that it is possible to maintain a low coercivity and a high permeability in thick sputtered Py films when reducing the out-of-plane component of the anisotropy by inserting thin film spacers of a non-magnetic material like Mo. For these kind of multilayers, we have found coercivities which are close to those for single layer films with no out-of-plane anisotropy. The coercivity is also dependent on the number of layers exhibiting a minimum value when each single Py layer has a thickness close to the transition thickness between Neel and Bloch domain walls.
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Magnetic transition in Co/(Gd-Co) multilayers
International Nuclear Information System (INIS)
Svalov, A.V.; Fernandez, A.; Barandiaran, J.M.; Vas'kovskiy, V.O.; Orue, I.; Tejedor, M.; Kurlyandskaya, G.V.
2008-01-01
[Co/Gd 0.36 Co 0.64 ] 4 /Co multilayers with Co termination layer have been prepared by rf sputtering. They form macroscopic ferrimagnets with a compensation temperature (T comp ) determined by the thickness ratio of the layers. In low fields the magnetization of Co and Gd-Co layers are along the axis of the applied field. Increasing field makes the moments of both the Co and Gd-Co layers deviate from the axis of the field giving rise to a transition into a twisted state. These magnetic transitions were studied by vibrating sample magnetometer (VSM), magneto-optic Kerr effect and magnetoresistance measurements at various temperatures. The nucleation and evolution of surface- and bulk-twisted magnetic states were also observed in these multilayers
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24 h stability of thick multilayer silicene in air
International Nuclear Information System (INIS)
De Padova, Paola; Ottaviani, Carlo; Quaresima, Claudio; Generosi, Amanda; Paci, Barbara; Le Lay, Guy; Olivieri, Bruno; Imperatori, Patrizia; Salomon, Eric; Angot, Thierry; Quagliano, Lucia; Romano, Claudia; Vona, Alessandro; Muniz-Miranda, Maurizio
2014-01-01
Thick epitaxial multilayer silicene films with a √3 × √3R(30°) surface structure show only mild surface oxidation after 24 h in air, as measured by Auger electron spectroscopy. X-ray diffraction and Raman spectroscopy measurements performed in air without any protective capping, as well as, for comparison, with a thin Al 2 O 3 cap, showed the (002) reflection and the G, D and 2D Raman structures, which are unique fingerprints of thick multilayer silicene. (letter)
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Electromigration in Cu(Al) and Cu(Mn) damascene lines
Hu, C.-K.; Ohm, J.; Gignac, L. M.; Breslin, C. M.; Mittal, S.; Bonilla, G.; Edelstein, D.; Rosenberg, R.; Choi, S.; An, J. J.; Simon, A. H.; Angyal, M. S.; Clevenger, L.; Maniscalco, J.; Nogami, T.; Penny, C.; Kim, B. Y.
2012-05-01
The effects of impurities, Mn or Al, on interface and grain boundary electromigration (EM) in Cu damascene lines were investigated. The addition of Mn or Al solute caused a reduction in diffusivity at the Cu/dielectric cap interface and the EM activation energies for both Cu-alloys were found to increase by about 0.2 eV as compared to pure Cu. Mn mitigated and Al enhanced Cu grain boundary diffusion; however, no significant mitigation in Cu grain boundary diffusion was observed in low Mn concentration samples. The activation energies for Cu grain boundary diffusion were found to be 0.74 ± 0.05 eV and 0.77 ± 0.05 eV for 1.5 μm wide polycrystalline lines with pure Cu and Cu (0.5 at. % Mn) seeds, respectively. The effective charge number in Cu grain boundaries Z*GB was estimated from drift velocity and was found to be about -0.4. A significant enhancement in EM lifetimes for Cu(Al) or low Mn concentration bamboo-polycrystalline and near-bamboo grain structures was observed but not for polycrystalline-only alloy lines. These results indicated that the existence of bamboo grains in bamboo-polycrystalline lines played a critical role in slowing down the EM-induced void growth rate. The bamboo grains act as Cu diffusion blocking boundaries for grain boundary mass flow, thus generating a mechanical stress-induced back flow counterbalancing the EM force, which is the equality known as the "Blech short length effect."
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Guided wave sensing of polyelectrolyte multilayers
DEFF Research Database (Denmark)
Horvath, R.; Pedersen, H.C.; Cuisinier, F.J.G.
2006-01-01
A planar optical waveguide configuration is proposed to monitor the buildup of thick polyelectrolyte multilayers on the surface of the waveguide in aqueous solutions. Instead of detecting the layer by the electromagnetic evanescent field the polyelectrolyte layer acts as an additional waveguiding...
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The visco-elastic multilayer program VEROAD
Hopman, P.C.
1996-01-01
The mathematical principles and derivation of a linear visco-elastic multilayer computer program are described. The mathematical derivation is based on Fourier Transformation. The program is called VEROAD, which is an acronym for Visco-Elastic ROad Analysis Delft. The program allows calculation of
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Magnetotransport and magnetization reversal of electrodeposited multilayer nanowires
Tang, Xueti
2007-12-01
Electrodeposited magnetic multilayer nanowires are ideal materials to study nanoscale magnetism and the giant magnetoresistance (GMR) in the current-perpendicular-to-plane (CPP) geometry. This is because the diameter of each nanowire is uniform, the surface of the nanowire is smooth, and the thickness of both the magnetic and non-magnetic layers can be varied to either larger or smaller than the spin diffusion length which is an important parameter in magnetotransport study. In addition, the aspect ratio (layer-thickness/diameter) that is related to shape anisotropy can be varied for magnetization reversal study. There has been little understanding in the magnetization reversal mechanism of multilayer nanowires, which is complicated due to the dipolar interactions between magnetic layers in each nanowire and between nanowires. The objective of this work is to study the magnetization reversal mechanism of multilayer nanowires using a vibrating sample magnetometer (VSM), where various dipolar interactions are taken into account. Although multilayer nanowires are ideal for the study of the CPP-GMR effect, there remains technical difficulty in making an electrical contact with individual nanowires for the CPP-GMR measurements. In this work, a point-contact method using a conductive plunger tip was developed in-house, that enabled us to measure the CPP-GMR of selected multilayer nanowires in an array of vertically aligned nanowires in each sample. To examine the CPP-GMR and compare the results with theoretical models, the CPP-GMR data were systematically obtained from samples with various magnetic and non-magnetic layer thicknesses. It was found from VSM measurement that the magnetization reversal mode in electrodeposited CoNi/Cu multilayer nanowires depends on the shape and thickness of the CoNi layers where the mode in rod-shaped thick CoNi layers is different from that in disk-shaped thin CoNi layers. The reversal mode in coherent rotation or curling was determined
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International Nuclear Information System (INIS)
Katona, G.L.; Berenyi, Z.; Vad, K.; Peter, L.
2006-01-01
Complete text of publication follows. Nanoscale multilayers have been in the focus of research since the discovery of the giant magnetoresistance (GMR) effect in this family of nanostructures. The first observation of GMR on sputtered magnetic/non-magnetic multilayers was followed by the detection of the same effect in electrodeposited Co-Ni-Cu/Cu multilayers within half a decade. Electrodeposition has long been considered as an inexpensive alternative of the high-vacuum methods to produce multilayers with GMR, although the GMR effect observed for electrodeposited multilayers is usually inferior to multilayers produced by physical methods. Electrochemistry appears to be an exclusive technology to produce multilayered nanowires by using porous templates. In spite of the large number of papers about the multilayers themselves, data on the depth profile of electrodeposited multilayer samples are very scarce. It has long been known that the simultaneous electrodeposition of the iron group metals takes place in the so-called anomalous manner. The diagnostic criterion of the anomalous codeposition is that the metallic component of lower standard potential (the Co in the case of Ni/Co) can be discharged together with the more noble one (Ni) at potentials where the less noble component (Co) alone cannot be deposited onto a substrate composed of the parent metal; moreover, the less noble metal (Co) is deposited preferentially. We have investigated the composition gradient along the growth direction of electrodeposited Co/Cu and CoNiCu/Cu multilayers films using SNMS. Samples were electrodeposited using the single bath method. Commercial Cu sheets and an Cr/Cu layer evaporated onto Si (111) surface were used as substrates with high and low roughness, respectively. The depth profiles of the samples were recorded using SNMS (INA-X, Specs GmbH, Berlin) in the Direct Bombardment Mode. Depth profile analysis of electrodeposited magnetic/nonmagnetic layered structures on
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Full Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction Systems
Su, Ji; Jiang, Xiaoning; Zu, Tian-Bing
2011-01-01
The Stacked HYBATS (Hybrid Actuation/Transduction system) demonstrates significantly enhanced electromechanical performance by using the cooperative contributions of the electromechanical responses of multilayer, stacked negative strain components and positive strain components. Both experimental and theoretical studies indicate that, for Stacked HYBATS, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The coupled resonance mode between positive strain and negative strain components of Stacked HYBATS is much stronger than the resonance of a single element actuation only when the effective lengths of the two kinds of elements match each other. Compared with the previously invented hybrid actuation system (HYBAS), the multilayer Stacked HYBATS can be designed to provide high mechanical load capability, low voltage driving, and a highly effective piezoelectric constant. The negative strain component will contract, and the positive strain component will expand in the length directions when an electric field is applied on the device. The interaction between the two elements makes an enhanced motion along the Z direction for Stacked-HYBATS. In order to dominate the dynamic length of Stacked-HYBATS by the negative strain component, the area of the cross-section for the negative strain component will be much larger than the total cross-section areas of the two positive strain components. The transverse strain is negative and longitudinal strain positive in inorganic materials, such as ceramics/single crystals. Different piezoelectric multilayer stack configurations can make a piezoelectric ceramic/single-crystal multilayer stack exhibit negative strain or positive strain at a certain direction without increasing the applied voltage. The difference of this innovation from the HYBAS is that all the elements can be made from one-of-a-kind materials. Stacked HYBATS can provide an extremely effective piezoelectric
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Nanosecond Surface Microdischarges in Multilayer Structures
Dubinov, A. E.; Lyubimtseva, V. A.
2018-05-01
Multilayer structures in which nanosecond surface microdischarges are generated have been developed, fabricated, and investigated. In these structures, layers are made in the form of thin transparent films, and a plasma discharge channel is formed in thin spacings between the layers. Passage of the discharge channel from one layer into the neighboring layer is implemented via pre-fabricated microholes. Images of microdischarges were obtained which confirmed that their plasma channels are formed according to the route assigned by the holes. The route may follow a fairly complex scheme and have self-intersection points and portions in which the electrons are bound to move in opposition to the electric field. In studying the shape of channels in multilayer strictures, the authors have found a new physical effect which lies in the azimuthal self-orientation of the discharge channel as it passes from one microhole to another.
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Low-loss compact multilayer silicon nitride platform for 3D photonic integrated circuits.
Shang, Kuanping; Pathak, Shibnath; Guan, Binbin; Liu, Guangyao; Yoo, S J B
2015-08-10
We design, fabricate, and demonstrate a silicon nitride (Si(3)N(4)) multilayer platform optimized for low-loss and compact multilayer photonic integrated circuits. The designed platform, with 200 nm thick waveguide core and 700 nm interlayer gap, is compatible for active thermal tuning and applicable to realizing compact photonic devices such as arrayed waveguide gratings (AWGs). We achieve ultra-low loss vertical couplers with 0.01 dB coupling loss, multilayer crossing loss of 0.167 dB at 90° crossing angle, 50 μm bending radius, 100 × 2 μm(2) footprint, lateral misalignment tolerance up to 400 nm, and less than -52 dB interlayer crosstalk at 1550 nm wavelength. Based on the designed platform, we demonstrate a 27 × 32 × 2 multilayer star coupler.
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International Nuclear Information System (INIS)
Qi, Jingshan; Li, Xiao; Qian, Xiaofeng
2016-01-01
Electrically controlled band gap and topological electronic states are important for the next-generation topological quantum devices. In this letter, we study the electric field control of band gap and topological phase transitions in multilayer germanane. We find that although the monolayer and multilayer germananes are normal insulators, a vertical electric field can significantly reduce the band gap of multilayer germananes owing to the giant Stark effect. The decrease of band gap eventually leads to band inversion, transforming them into topological insulators with nontrivial Z_2 invariant. The electrically controlled topological phase transition in multilayer germananes provides a potential route to manipulate topologically protected edge states and design topological quantum devices. This strategy should be generally applicable to a broad range of materials, including other two-dimensional materials and ultrathin films with controlled growth.
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Electrohydrodynamic direct—writing of conductor—insulator-conductor multi-layer interconnection
International Nuclear Information System (INIS)
Zheng Gao-Feng; Pei Yan-Bo; Wang Xiang; Zheng Jian-Yi; Sun Dao-Heng
2014-01-01
A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing (EDW) is utilized to print the conductor—insulator—conductor multi-layer interconnection structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone (PVP) solution is utilized to fabricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained results show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10 −7 Ω·m and 1.39 × 10 −7 Ω·m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor—insulator—conductor multi-layer interconnections in the electronic industry
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Interfacial pattern changes of imprinted multilayered material in milli- and microscales
Yonekura, Kazuhiro; Tokumaru, Kazuki; Tsumori, Fujio
2018-06-01
Nanoimprint lithography (NIL) is a technique that transfers a mold pattern of nanometer order to the surface of a resist material by heating and pressing. NIL is an excellent technology in terms of high productivity, accuracy, and resolution. Recently, NIL has been applied to the processing of different multilayered materials, in which it is possible to process multiple materials simultaneously. In this processing of multilayered materials, it is possible to form an interfacial pattern between the upper layer and the lower layer simultaneously with patterning on the mold surface. This interface pattern can be controlled by the deformation characteristics, initial thickness, and so forth. In this research, we compared the interfacial pattern changes of imprinted multilayered materials in milli- and microscales. For multilayered imprint using multiple materials, it is important to know the flow of the resist and its dependence on the scale. If there is similarity in the relationship produced by the scale on the imprinted samples, a process design with a number of feedbacks could be realized. It also becomes easier to treat structures in the millimeter scale for the experiment. In this study, we employed micropowder imprint (µPI) for multilayered material imprint. A compound sheet of alumina powder and polymer binder was used for imprint. Two similar experiments in different scales, micro- and millimeter scales, were carried out. Results indicate that the interfacial patterns of micro- and millimeter-scale-imprinted samples are similar.
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Nano selenium as antioxidant agent in a multilayer food packaging material.
Vera, Paula; Echegoyen, Yolanda; Canellas, Elena; Nerín, Cristina; Palomo, María; Madrid, Yolanda; Cámara, Carmen
2016-09-01
Selenium nanoparticles (SeNPs) were incorporated in a flexible multilayer plastic material using a water-base adhesive as vehicle for SeNPs. The antioxidant performance of the original solutions containing spherical SeNPs of 50-60 nm diameter, the adhesive containing these SeNPs, and the final multilayer plastic material to be used as food packaging were quantitatively measured. The radical scavenging capacity due to SeNPs was quantified by a free radical assay developed in the laboratory and by the diphenyl-1-picrylhydrazyl (DPPH) method. DPPH was not efficient to measure the scavenging capacity in the multilayer when the free radical scavenger is not in the surface in contact with it. Several multilayer laminated structures composed by [PET (20 m)-adhesive-LDPE (with variable thickness from 35 to 90 μm)] were prepared and measured, demonstrating for the first time that free radicals derived from oxygen (OH·, O2·, and O2H) cross the PE layer and arrive at the adhesive. SeNPs remain as such after manufacture and the final laminate is stable after 3 months of storage. The antioxidant multilayer is a non-migrating efficient free radical scavenger, able to protect the packaged product versus oxidation and extending the shelf life without being in direct contact with the product. Migration tests of both Se and SeNPs to simulants and hazelnuts demonstrated the non-migrating performance of this new active packaging. Graphical abstract ᅟ.
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Van der Waals epitaxy of GaN-based light-emitting diodes on wet-transferred multilayer graphene film
Li, Yang; Zhao, Yun; Wei, Tongbo; Liu, Zhiqiang; Duan, Ruifei; Wang, Yunyu; Zhang, Xiang; Wu, QingQing; Yan, Jianchang; Yi, Xiaoyao; Yuan, Guodong; Wang, Junxi; Li, Jimin
2017-08-01
We experimentally investigated the possibility of using multilayer graphene to solve large mismatch problems between sapphire and nitride and further studied the effects of a multilayer graphene interlayer on the optical and electrical properties of LEDs. For the subsequent growth of 3-µm-thick GaN on AlN, multilayer graphene helps release stress and effectively removes cracks. In addition, multilayer graphene increases the diffraction of the substrate surface as determined from the increase in optical transmittance spectra in the wavelength range of 400-900 nm. Although the crystalline quality of GaN with multilayer graphene is slightly decreased, LEDs grown on multilayer graphene still show a higher output power than those grown on conventional sapphire. The present findings showed that the multilayer graphene layer is attractive as a potential substrate for the epitaxial growth of III-nitride to reduce stress and it could improve back light extraction as a rough layer to increase external quantum efficiency.
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Directory of Open Access Journals (Sweden)
Ann-Kathrin Kleinschmidt
2016-11-01
Full Text Available Reflectance anisotropy spectroscopy (RAS equipment is applied to monitor dry-etch processes (here specifically reactive ion etching (RIE of monocrystalline multilayered III–V semiconductors in situ. The related accuracy of etch depth control is better than 16 nm. Comparison with results of secondary ion mass spectrometry (SIMS reveals a deviation of only about 4 nm in optimal cases. To illustrate the applicability of the reported method in every day settings for the first time the highly etch depth sensitive lithographic process to form a film lens on the waveguide ridge of a broad area laser (BAL is presented. This example elucidates the benefits of the method in semiconductor device fabrication and also suggests how to fulfill design requirements for the sample in order to make RAS control possible.
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Multilayer porous UHMWPE scaffolds for bone defects replacement.
Maksimkin, A V; Senatov, F S; Anisimova, N Yu; Kiselevskiy, M V; Zalepugin, D Yu; Chernyshova, I V; Tilkunova, N A; Kaloshkin, S D
2017-04-01
Reconstruction of the structural integrity of the damaged bone tissue is an urgent problem. UHMWPE may be potentially used for the manufacture of porous implants simulating as closely as possible the porous cancellous bone tissue. But the extremely high molecular weight of the polymer does not allow using traditional methods of foaming. Porous and multilayer UHMWPE scaffolds with nonporous bulk layer and porous layer that mimics cancellous bone architecture were obtained by solid-state mixing, thermopressing and washing in subcritical water. Structural and mechanical properties of the samples were studied. Porous UHMWPE samples were also studied in vitro and in vivo. The pores of UHMWPE scaffold are open and interconnected. Volume porosity of the obtained samples was 79±2%; the pore size range was 80-700μm. Strong connection of the two layers in multilayer UHMWPE scaffolds was observed with decreased number of fusion defects. Functionality of implants based on multilayer UHMWPE scaffolds is provided by the fixation of scaffolds in the bone defect through ingrowths of the connective tissue into the pores, which ensures the maintenance of the animals' mobility. Copyright © 2016 Elsevier B.V. All rights reserved.
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Energy Technology Data Exchange (ETDEWEB)
Zhang, Chao [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240 (China); Feng, Kai, E-mail: fengkai@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240 (China); Li, Zhuguo, E-mail: lizg@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240 (China); Lu, Fenggui; Huang, Jian; Wu, Yixiong [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration, Shanghai 200240 (China)
2016-08-15
Highlights: • Ni/Ni{sub 3}Al multilayers are prepared by magnetron sputtering. • Both grain size and phase constitution of annealed Ni/Ni{sub 3}Al multilayers are dependent on individual layer thickness. • The hardness of annealed Ni/Ni{sub 3}Al multilayers varies with individual layer thickness and annealing temperature. • 40 nm Ni/Ni{sub 3}Al multilayer exhibits excellent hardness at elevated temperature. - Abstract: Nano-structured Ni/Ni{sub 3}Al multilayer was prepared by magnetron sputtering, with individual layer thicknesses h varying from 10 to 160 nm. The microstructure and hardness of Ni/Ni{sub 3}Al multilayer were investigated by X-ray diffraction, transmission electron microscopy and nanoindentation. The results show that the hardness increases with decreasing h for as-deposited and 500 °C annealed multilayers. When annealed at 700 °C, the hardness approach a peak value at h = 40 nm with followed by softening at smaller h. The influence of individual layer thickness, grain size as well as formation of ordered Ni{sub 3}Al on strengthening mechanisms of Ni/Ni{sub 3}Al multilayers at elevated temperature are discussed.
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Dipole radiation in a multilayer geometry
International Nuclear Information System (INIS)
Reed, C.E.; Giergiel, J.; Hemminger, J.C.; Ushioda, S.
1987-01-01
There are several kinds of experiments that can be done with multilayer stacks of dielectric media which require an understanding of light emission by sources within the stack for their analysis. These experiments may involve, for example, light-emitting tunnel junctions, Raman scattering in Kretschmann and other multilayered geometries, and Rayleigh scattering by small amounts of surface or interface roughness, either alone or in combination with other processes. A set of electromagnetic Green's functions for a multilayer stack of isotropic dielectric media [D. L. Mills and A. A. Maradudin, Phys. Rev. B 12, 2943 (1975)] gives the electric fields produced everywhere by a point source of current oscillating at a frequency f. These Green's functions can thus be used to solve this type of problem. In this paper we show how these Green's functions can be written in terms of 2 x 2 transfer matrices of the type commonly used to find the fields in a dielectric stack due to an incident plane wave. With this simplification we can easily evaluate the Green's functions for a stack with an arbitrary number of layers. We further show that, when the electric fields generated by a point source within the stack are evaluated far away, they can be written directly in terms of the electric fields that would be generated at the location of the current source by plane waves incident from the direction of the observation point. We show that this follows from the Lorentz reciprocity theorem. Thus, in this case the formalism of Green's functions is not needed
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Exploring the magnetization dynamics of NiFe/Pt multilayers in flexible substrates
Energy Technology Data Exchange (ETDEWEB)
Corrêa, M.A., E-mail: marciocorrea@dfte.ufrn.br [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Dutra, R.; Marcondes, T.L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil); Mori, T.J.A. [Laboratório Nacional de Luz Síncrotron, Rua Giuseppe Máximo Scolfaro, 1000, Guará, 13083-100 Campinas, SP (Brazil); Bohn, F. [Departamento de Física Teórica e Experimental, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Sommer, R.L. [Centro Brasileiro de Pesquisas Físicas, Rua Dr. Xavier Sigaud, 150, Urca, 22290-180 Rio de Janeiro, RJ (Brazil)
2016-09-15
Highlights: • Magnetic properties of multilayers grown onto flexible substrates were investigated. • Experimental and theoretical magnetization dynamics results are presented. • The flexible substrates become promising candidate for rf-frequency devices. - Abstract: We investigate the structural and magnetic properties, and the magnetization dynamics in Ni{sub 81}Fe{sub 19}/Pt multilayer systems grown onto rigid and flexible substrates. The structural characterization shows evidence of a superlattice behavior, while the quasi-static magnetization characterization reveal a weak magnetic anisotropy induced in the multilayers. The magnetization dynamics is investigated through the magnetoimpedance effect. We employ a theoretical approach to describe the experimental magnetoimpedance effect and verify the influence of the effective damping parameter on the magnetization dynamics. Experimental data and theoretical results are in agreement and suggest that the multilayers present high effective damping parameter. Moreover, our experiments raise an interesting issue on the possibility of achieving considerable MI% values, even for systems with weak magnetic anisotropy and high damping parameter grown onto flexible substrates.
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Multi-layer micro/nanofluid devices with bio-nanovalves
Li, Hao; Ocola, Leonidas E.; Auciello, Orlando H.; Firestone, Millicent A.
2013-01-01
A user-friendly multi-layer micro/nanofluidic flow device and micro/nano fabrication process are provided for numerous uses. The multi-layer micro/nanofluidic flow device can comprise: a substrate, such as indium tin oxide coated glass (ITO glass); a conductive layer of ferroelectric material, preferably comprising a PZT layer of lead zirconate titanate (PZT) positioned on the substrate; electrodes connected to the conductive layer; a nanofluidics layer positioned on the conductive layer and defining nanochannels; a microfluidics layer positioned upon the nanofluidics layer and defining microchannels; and biomolecular nanovalves providing bio-nanovalves which are moveable from a closed position to an open position to control fluid flow at a nanoscale.
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Sculpted-multilayer optical effects in two species of Papilio butterfly
International Nuclear Information System (INIS)
Vukusic, Peter; Sambles, Roy; Lawrence, Christopher; Wakely, Gavin
2001-01-01
The wing-scale microstructures associated with two species of Papilio butterfly are described and characterized. Despite close similarities in their structures, they do not exhibit analogous optical effects. With Papilio palinurus, deep modulations in its multilayering create bicolor reflectivity with strong polarization effects, and this leads to additive color mixing in certain visual systems. In contrast to this, Papilio ulysses features shallow multilayer modulation that produces monocolor reflectivity without significant polarization effects
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Influence of plasticity mismatch and porosity on mechanical behavior of nanoscale Ag/W multilayers
International Nuclear Information System (INIS)
Wen, S.P.; Zong, R.L.; Zeng, F.; Gao, Y.; Pan, F.
2007-01-01
Ag/W multilayers with periodicity ranging from 15 to 200 nm were deposited by direct current magnetron sputtering. The microstructure, hardness and elastic modulus were investigated by X-ray diffraction, Rutherford backscattering, X-ray fluorescence, scanning electron microscopy and nanoindentation. The results show that multilayers with periodicity less than 50 nm have columnar porous structure, which leads to low modulus and brittle fracture. Multilayers with periodicity larger than 50 nm have continuous laminated structure, and they are relatively ductile. All the multilayers have abnormal low hardness far less than a rule of mixture value, which has been attributed to porous structure and the deformation localization due to the plasticity mismatch between Ag and W
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Filter construction technology in mining drilling hole for in-situ leaching of multilayer deposit
International Nuclear Information System (INIS)
Jiang Yan; Hu Baishi; Tan Yahui; Yang Lizhi; Li Xiaojian; Wang Xiaodong; Chang Jingtao; Qin Hao
2014-01-01
Taking a typical multilayer sandstone uranium deposit as example, study was carried out on filter construction technology in mining drilling hole for in-situ leaching of multilayer deposit. According to the character of multilayer sandstone, four injecting holes and one drawning hole were designed between the P13-P15 exploration lines, five different methods were used to construct filter. Construction technology by different methods was introduced and the advantages and disadvantages of the construction filter with five methods were analysed. As far as five experimental drilling holes, layered gravel-filling hole construction technology is a suitable method for construction multilayer filter with continuous construction, simple operation and good effect of well completion. (authors)
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2012-07-31
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-970] Multilayered Wood Flooring... on multilayered wood flooring from the People's Republic of China (``PRC'') meets the statutory and... announcing the antidumping duty order on multilayered wood flooring from the PRC was published in the Federal...
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2013-07-31
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-970] Multilayered Wood Flooring... antidumping duty order on multilayered wood flooring from the People's Republic of China (``PRC'') meet the...: Background The Department published the antidumping duty order on multilayered wood flooring from the PRC on...
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Magnetic field decoupling and 3D-2D crossover in Nb/Cu multilayers
DEFF Research Database (Denmark)
Krasnov, V.M.; Kovalev, A.E.; Oboznov, V.A.
1996-01-01
magnetic field and by the multiply branched I-V curves caused by flux-flow of Josephson vortices in the stacked superconductor-normal-metal-superconductor junctions composing the multilayer. By measurements across layers the ''breaking field'' at which the proximity induced superconductivity in the normal...... layers of superconductor-normal-metal (Nb/Cu) multilayers is destroyed was observed directly. A dimensionality diagram in the (H-T) plane was deduced from our data. Reasons for complication of the ''Fraunhofer pattern,'' I-c(H), in ''long'' multilayers are discussed....
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Subwavelength resolution from multilayered structure (Conference Presentation)
Cheng, Bo Han; Jen, Yi-Jun; Liu, Wei-Chih; Lin, Shan-wen; Lan, Yung-Chiang; Tsai, Din Ping
2016-10-01
Breaking optical diffraction limit is one of the most important issues needed to be overcome for the demand of high-density optoelectronic components. Here, a multilayered structure which consists of alternating semiconductor and dielectric layers for breaking optical diffraction limitation at THz frequency region are proposed and analyzed. We numerically demonstrate that such multilayered structure not only can act as a hyperbolic metamaterial but also a birefringence material via the control of the external temperature (or magnetic field). A practical approach is provided to control all the diffraction signals toward a specific direction by using transfer matrix method and effective medium theory. Numerical calculations and computer simulation (based on finite element method, FEM) are carried out, which agree well with each other. The temperature (or magnetic field) parameter can be tuned to create an effective material with nearly flat isofrequency feature to transfer (project) all the k-space signals excited from the object to be resolved to the image plane. Furthermore, this multilayered structure can resolve subwavelength structures at various incident THz light sources simultaneously. In addition, the resolution power for a fixed operating frequency also can be tuned by only changing the magnitude of external magnetic field. Such a device provides a practical route for multi-functional material, photolithography and real-time super-resolution image.
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Li, Yajie; Pu, Hongting
2018-04-01
Polypropylene (PP)/polyethylene (PE) multilayer separators with cellular-like submicron pore structure for lithium-ion battery are efficiently fabricated by the combination of multilayer coextrusion (MC) and thermal induced phase separation (TIPS). The as-prepared separators, referred to as MC-TIPS PP/PE, not only show efficacious thermal shutdown function and wider shutdown temperature window, but also exhibit higher thermal stability than the commercial separator with trilayer construction of PP and PE (Celgard® 2325). The dimensional shrinkage of MC-TIPS PP/PE can be negligible until 160 °C. In addition, compared to the commercial separator, MC-TIPS PP/PE exhibits higher porosity and electrolyte uptake, leading to higher ionic conductivity and better battery performances. The above-mentioned fascinating characteristics with the convenient preparation process make MC-TIPS PP/PE a promising candidate for the application as high performance lithium-ion battery separators.
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Josephson plasma resonance in superconducting multilayers
DEFF Research Database (Denmark)
Pedersen, Niels Falsig; Sakai, S
1998-01-01
We derive an analytical solution for the Josephson plasma resonance of superconducting multilayers. This analytical solution is derived mainly for low-T-c systems with magnetic coupling between the superconducting layers. but many features of our results are more general, and thus an application...
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Asymmetric magnetization reversal in exchange-biased Co/Pt multilayers
Energy Technology Data Exchange (ETDEWEB)
Dijken, Sebastiaan van [SFI Trintiy Nanoscience Laboratory, Physics Department, Trinity College, Dublin 2 (Ireland); Czapkiewicz, M.; Zoladz, M.; Stobiecki, T. [Department of Electronics, AGH University of Science and Technology, Krakow 30-059 (Poland)
2006-01-01
A detailed study of the magnetization reversal process in [20 Aa Pt/t Aa Co]{sub 3}/100 Aa IrMn/20 Aa Pt multilayers with 4 Aa{<=}t{<=}9 Aa is presented. The hysteresis of as-deposited films with t{>=} 5Aa is found to be asymmetric. This asymmetry is explained by a lateral variation in the perpendicular exchange bias direction due to the growth of IrMn onto multi-domain Co/Pt multilayers. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
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Soft-x-ray fluorescence study of buried silicides in antiferromagnetically coupled Fe/Si multilayers
Energy Technology Data Exchange (ETDEWEB)
Carlisle, J.A.; Chaiken, A.; Michel, R.P. [Lawrence Berkeley National Lab., CA (United States)] [and others
1997-04-01
Multilayer films made by alternate deposition of two materials play an important role in electronic and optical devices such as quantum-well lasers and x-ray mirrors. In addition, novel phenomena like giant magnetoresistance and dimensional crossover in superconductors have emerged from studies of multilayers. While sophisticated x-ray techniques are widely used to study the morphology of multilayer films, progress in studying the electronic structure has been slower. The short mean-free path of low-energy electrons severely limits the usefulness of photoemission and related electron free path of low-energy electrons severely limit spectroscopies for multilayer studies. Soft x-ray fluorescence (SXF) is a bulk-sensitive photon-in, photon-out method to study valence band electronic states. Near-edge x-ray absorption fine-structure spectroscopy (NEXAFS) measured with partial photon yield can give complementary bulk-sensitive information about unoccupied states. Both these methods are element-specific since the incident x-ray photons excite electrons from core levels. By combining NEXAFS and SXF measurements on buried layers in multilayers and comparing these spectra to data on appropriate reference compounds, it is possible to obtain a detailed picture of the electronic structure. Results are presented for a study of a Fe/Si multilayer system.
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Soft-x-ray fluorescence study of buried silicides in antiferromagnetically coupled Fe/Si multilayers
International Nuclear Information System (INIS)
Carlisle, J.A.; Chaiken, A.; Michel, R.P.
1997-01-01
Multilayer films made by alternate deposition of two materials play an important role in electronic and optical devices such as quantum-well lasers and x-ray mirrors. In addition, novel phenomena like giant magnetoresistance and dimensional crossover in superconductors have emerged from studies of multilayers. While sophisticated x-ray techniques are widely used to study the morphology of multilayer films, progress in studying the electronic structure has been slower. The short mean-free path of low-energy electrons severely limits the usefulness of photoemission and related electron free path of low-energy electrons severely limit spectroscopies for multilayer studies. Soft x-ray fluorescence (SXF) is a bulk-sensitive photon-in, photon-out method to study valence band electronic states. Near-edge x-ray absorption fine-structure spectroscopy (NEXAFS) measured with partial photon yield can give complementary bulk-sensitive information about unoccupied states. Both these methods are element-specific since the incident x-ray photons excite electrons from core levels. By combining NEXAFS and SXF measurements on buried layers in multilayers and comparing these spectra to data on appropriate reference compounds, it is possible to obtain a detailed picture of the electronic structure. Results are presented for a study of a Fe/Si multilayer system
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Magnetic-plasmonic multilayered nanorods
Thumthan, Orathai
Multilayered nanorods which consist of alternating magnetic layers separated by Au layers combine two distinctive properties, magnetic properties and surface plasmonic resonance (SPR) properties into one nano-entity. Their magnetic properties are tunable by changing the layer thickness, varying from single domain to superparamagnetic state. Superparamagnetic is a key requirement for magnetic nanoparticles for bioapplications. Superparamagnetic nanoparticles exhibit high magnetic moments at low applied magnetic field while retain no magnetic moments when magnetic field is removed preventing them from aggregation due to magnetic attraction. Au layers in the nanorods provide anchorage sites for functional group attachment. Also, Au nanodisks exhibit SPR properties. The SPR peak can be tuned from 540 nm to 820 nm by controlling the thickness of magnetic segments while keeping Au thickness constant. In this research, there are three types of multilayered nanorod have been fabricated: Au/NiFe nanorods, Au/Fe nanorods, and Au/Co nanorods. These magnetic nanorods were fabricated by templated electrodeposition into the channels in Anodic Aluminum Oxide (AAO) membrane. The setup for AAO fabrication was developed as a part of this research. Our fabricated AAO membrane has channels with a diameter ranging from 40nm to 80 nm and a thickness of 10um to 12um. Magnetic properties of nanorods such as saturation field, saturation moment, coercivity and remanence are able to manipulate through their shape anisotropy. The magnetization will be easier in long axis rather than short axis of particle. In addition, Au nanodisks in the nanorod structure are not only serving as anchorage sites for functional groups but also provide SPR properties. Under irradiation of light Au nanodisks strongly absorb light at SPR frequency which ranging from 540 nm to 820 nm by controlling the thickness of magnetic segments while keeping Au thickness constant. The SPR tunability of nanorods in near
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Thinning of multilayer graphene to monolayer graphene in a plasma environment
International Nuclear Information System (INIS)
Hazra, K S; Misra, D S; Rafiee, J; Rafiee, M A; Koratkar, N; Mathur, A; Roy, S S; McLauhglin, J
2011-01-01
We present a facile approach to transform multilayer graphene to single-layer graphene in a gradual thinning process. Our technique is based upon gradual etching of multilayer graphene in a hydrogen and nitrogen plasma environment. High resolution transmission microscopy, selected area electron diffraction and Raman spectroscopy confirm the transformation of multilayer graphene to monolayer graphene at a substrate temperature of ∼ 400 0 C. The shift in the position of the G-band peak shows a perfect linear dependence with substrate temperature, which indicates a controlled gradual etching process. Selected area electron diffraction also confirmed the removal of functional groups from the graphene surface due to the plasma treatment. We also show that plasma treatment can be used to engineer graphene nanomesh structures.
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High energy PIXE: A tool to characterize multi-layer thick samples
Subercaze, A.; Koumeir, C.; Métivier, V.; Servagent, N.; Guertin, A.; Haddad, F.
2018-02-01
High energy PIXE is a useful and non-destructive tool to characterize multi-layer thick samples such as cultural heritage objects. In a previous work, we demonstrated the possibility to perform quantitative analysis of simple multi-layer samples using high energy PIXE, without any assumption on their composition. In this work an in-depth study of the parameters involved in the method previously published is proposed. Its extension to more complex samples with a repeated layer is also presented. Experiments have been performed at the ARRONAX cyclotron using 68 MeV protons. The thicknesses and sequences of a multi-layer sample including two different layers of the same element have been determined. Performances and limits of this method are presented and discussed.
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Fakhar-E-Alam, Muhammad; Akram, M. Waseem; Iqbal, Seemab; Alimgeer, K. S.; Atif, M.; Sultana, K.; Willander, M.; Wang, Zhiming M.
2017-04-01
Carcinogenesis is a complex molecular process starting with genetic and epigenetic alterations, mutation stimulation, and DNA modification, which leads to proteomic adaptation ending with an uncontrolled proliferation mechanism. The current research focused on the empirical modelling of the physiological response of human melanoma cells (FM55P) and human foreskin fibroblasts cells (AG01518) to the multilayer zinc oxide (ZnO) nanomaterials under UV-A exposure. To validate this experimental scheme, multilayer ZnO nanomaterials were grown on a femtotip silver capillary and conjugated with protoporphyrin IX (PpIX). Furthermore, PpIX-conjugated ZnO nanomaterials grown on the probe were inserted into human melanoma (FM55P) and foreskin fibroblasts cells (AG01518) under UV-A light exposure. Interestingly, significant cell necrosis was observed because of a loss in mitochondrial membrane potential just after insertion of the femtotip tool. Intense reactive oxygen species (ROS) fluorescence was observed after exposure to the ZnO NWs conjugated with PpIX femtotip model under UV exposure. Results were verified by applying several experimental techniques, e.g., ROS detection, MTT assay, and fluorescence spectroscopy. The present work reports experimental modelling of cell necrosis in normal human skin as well as a cancerous tissue. These obtained results pave the way for a more rational strategy for biomedical and clinical applications.
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Energy Technology Data Exchange (ETDEWEB)
Vokkarane, Vinod [University of Massachusetts
2013-09-01
We intend to implement a Coordinated Multi-layer Multi-domain Optical Network (COMMON) Framework for Large-scale Science Applications. In the COMMON project, specific problems to be addressed include 1) anycast/multicast/manycast request provisioning, 2) deployable OSCARS enhancements, 3) multi-layer, multi-domain quality of service (QoS), and 4) multi-layer, multidomain path survivability. In what follows, we outline the progress in the above categories (Year 1, 2, and 3 deliverables).
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Synthesis and characterization of Cu–Al–Ni shape memory alloy multilayer thin films
International Nuclear Information System (INIS)
Gómez-Cortés, J.F.; San Juan, J.; López, G.A.; Nó, M.L.
2013-01-01
Among active materials, shape memory alloys are well recognized for their work output density. Because of that, these alloys have attracted much attention to be used in micro/nano electromechanical systems. In the present work, the electron beam evaporation technique has been used to growth, by a multilayer method, two shape memory alloy thin films with different Cu–Al–Ni composition. Multilayers have been further thermally treated to produce the alloys by solid solution diffusion. The produced multilayers have been characterized and the presence of the martensite phase in the obtained thin films was studied. Furthermore, the influence of two different coatings onto the Si substrates, namely Si/SiO 2 and Si/Si 3 N 4 , was investigated. Mechanically stable, not detaching from the substrates, Cu–Al–Ni shape memory alloy thin films, about 1 micrometre thick, showing a martensitic transformation have been produced. - Highlights: ► Multilayer thin films of Cu–Al–Ni shape memory alloys produced by e-beam evaporation. ► SiN X 200 nm thick coating is good for high quality Cu–Al–Ni shape memory thin films. ► Thermal treatment renders Cu–Al–Ni multilayer in homogeneous martensite thin film
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High reflectance Cr/C multilayer at 250 eV for soft X-ray polarimetry
Energy Technology Data Exchange (ETDEWEB)
Wen, Mingwu; Jiang, Li; Zhang, Zhong; Huang, Qiushi [MOE Key Laboratory of Advanced Micro-Structured Materials, Institute of Precision Optical Engineering (IPOE), School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Wang, Zhanshan, E-mail: wangzs@tongji.edu.cn [MOE Key Laboratory of Advanced Micro-Structured Materials, Institute of Precision Optical Engineering (IPOE), School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); She, Rui; Feng, Hua [Department of Engineering Physics, Tsinghua University, Beijing (China); Wang, Hongchang [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom)
2015-10-01
X-ray reflection near 45° via multilayer mirrors can be used for astronomical polarization measurements. A Cr/C multilayer mirror (designed for X-ray polarimetry at 250 eV), with a period thickness of 3.86 nm and a bi-layer number of 100, was fabricated using direct current magnetron sputtering. Grazing incidence X-ray reflectometry at 8 keV and transmission electron microscopy were used to investigate the multilayer structure. Different models were introduced to fit the hard X-ray reflectivity curve, which indicates that the layer thickness of two materials slightly drifts from the bottom to the top of the stack. Both the chromium and carbon layers are amorphous with asymmetric interfaces, while the Cr-on-C interface is slightly wider. Based on the good quality of the multilayer structure, a high reflectivity of 21.8% for the s-polarized light was obtained at 250 eV at a grazing incidence angle of 40.7°. The fabricated Cr/C multilayer mirror exhibits high reflectivity and polarization levels in the energy region of 240 eV–260 eV. - Highlights: • We fabricated Cr/C multilayer with 3.8 nm d-spacing. • X-ray reflectometry was used to determine the exact structure of Cr/C multilayer. • A high reflectivity of 21.8% for the s-polarized light was obtained at 250 eV. • Both Cr and C were found to be amorphous with slightly asymmetric interfaces. • A 4-layer model was used to fit and explain the results.
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Integrated Multilayer Insulation
Dye, Scott
2009-01-01
Integrated multilayer insulation (IMLI) is being developed as an improved alternative to conventional multilayer insulation (MLI), which is more than 50 years old. A typical conventional MLI blanket comprises between 10 and 120 metallized polymer films separated by polyester nets. MLI is the best thermal- insulation material for use in a vacuum, and is the insulation material of choice for spacecraft and cryogenic systems. However, conventional MLI has several disadvantages: It is difficult or impossible to maintain the desired value of gap distance between the film layers (and consequently, it is difficult or impossible to ensure consistent performance), and fabrication and installation are labor-intensive and difficult. The development of IMLI is intended to overcome these disadvantages to some extent and to offer some additional advantages over conventional MLI. The main difference between IMLI and conventional MLI lies in the method of maintaining the gaps between the film layers. In IMLI, the film layers are separated by what its developers call a micro-molded discrete matrix, which can be loosely characterized as consisting of arrays of highly engineered, small, lightweight, polymer (typically, thermoplastic) frames attached to, and placed between, the film layers. The term "micro-molded" refers to both the smallness of the frames and the fact that they are fabricated in a process that forms precise small features, described below, that are essential to attainment of the desired properties. The term "discrete" refers to the nature of the matrix as consisting of separate frames, in contradistinction to a unitary frame spanning entire volume of an insulation blanket.
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DEFF Research Database (Denmark)
Zhukovsky, Sergei; Andryieuski, Andrei; Takayama, Osamu
2015-01-01
We report the first experimental demonstration of anomalous breakdown of the effective medium approximation in all-dielectric deeply subwavelength thickness (d∼λ/160-λ/30) multilayers, as recently predicted theoretically [H. H. Sheinfux et al., Phys. Rev. Lett. 113, 243901 (2014)]. Multilayer...... stacks are composed of alternating alumina and titania layers fabricated using atomic layer deposition. For light incident on such multilayers at angles near the total internal reflection, we observe pronounced differences in the reflectance spectra for structures with 10- vs 20-nm thick layers, as well...
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Structural and magnetic properties of Ce/Fe and Ce/FeCoV multilayers
Energy Technology Data Exchange (ETDEWEB)
Tixier, S; Boeni, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Mannix, D; Stirling, W G [Liverpool Univ. (United Kingdom); Lander, G H
1997-09-01
Ce/Fe and Ce/FeCoV multilayers have been grown by magnetron sputtering. The interfaces are well defined and the layers are crystalline down to an individual layer thickness of 20 A. Ce/FeCoV multilayers show sharper interfaces than Ce/Fe but some loss of crystallinity is observed. Hysteresis loops obtained by SQUID show different behaviour of the bulk magnetisation as a function of the layer thickness. Fe moments are found by Moessbauer spectroscopy to be perpendicular to the interfaces for multilayers with small periodicity. (author) 2 figs., 2 refs.
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Measure of Node Similarity in Multilayer Networks
DEFF Research Database (Denmark)
Møllgaard, Anders; Zettler, Ingo; Dammeyer, Jesper
2016-01-01
The weight of links in a network is often related to the similarity of thenodes. Here, we introduce a simple tunable measure for analysing the similarityof nodes across different link weights. In particular, we use the measure toanalyze homophily in a group of 659 freshman students at a large...... university.Our analysis is based on data obtained using smartphones equipped with customdata collection software, complemented by questionnaire-based data. The networkof social contacts is represented as a weighted multilayer network constructedfrom different channels of telecommunication as well as data...... might bepresent in one layer of the multilayer network and simultaneously be absent inthe other layers. For a variable such as gender, our measure reveals atransition from similarity between nodes connected with links of relatively lowweight to dis-similarity for the nodes connected by the strongest...
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The Impedance of Multi-layer Vacuum Chambers
Vos, L
2003-01-01
Many components of the LHC vacuum chamber have multi-layered walls : the copper coated cold beam screen, the titanium coated ceramic chamber of the dump kickers, the ceramic chamber of the injection kickers coated with copper stripes, only to name a few. Theories and computer programs are available for some time already to evaluate the impedance of these elements. Nevertheless, the algorithm developed in this paper is more convenient in its application and has been used extensively in the design phase of multi-layer LHC vacuum chamber elements. It is based on classical transmission line theory. Closed expressions are derived for simple layer configurations, while beam pipes involving many layers demand a chain calculation. The algorithm has been tested with a number of published examples and was verified with experimental data as well.
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International Nuclear Information System (INIS)
Sato, Satoshi; Maegawa, Toshio; Yoshimatsu, Kenji; Sato, Koichi; Nonaka, Akira; Takakura, Kosuke; Ochiai, Kentaro; Konno, Chikara
2011-01-01
A multi-layered concrete structure has been developed to reduce induced activity in the shielding for neutron generating facilities such as a fusion reactor. The multi-layered concrete structure is composed of: (1) an inner low activation concrete, (2) a boron-doped low activation concrete as the second layer, and (3) ordinary concrete as the outer layer of the neutron shield. With the multi-layered concrete structure the volume of boron is drastically decreased compared to a monolithic boron-doped concrete. A 14 MeV neutron shielding experiment with multi-layered concrete structure mockups was performed at FNS and several reaction rates and induced activity in the mockups were measured. This demonstrated that the multi-layered concrete effectively reduced low energy neutrons and induced activity.
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Robust Multilayer Graphene-Organic Frameworks for Selective Separation of Monovalent Anions.
Zhao, Yan; Zhu, Jiajie; Li, Jian; Zhao, Zhijuan; Charchalac Ochoa, Sebastian Ignacio; Shen, Jiangnan; Gao, Congjie; Van der Bruggen, Bart
2018-05-30
The chemical and mechanical stability of graphene nanosheets was used in this work to design a multilayer architecture of graphene, grafted with sulfonated 4,4'-diaminodiphenyl sulfone (SDDS). Quaternized poly(phenylene oxide) (QPPO) was synthesized and mixed with SDDS (rGO-SDDS-rGO@QPPO), yielding a multilayer graphene-organic framework (MGOF) with positive as well as negative functional groups that can be applied as a versatile electrodriven membrane in electrodialysis (ED). Multilayer graphene-organic frameworks are a new class of multilayer structures, with an architecture having a tunable interlayer spacing connected by cationic polymer material. MGOF membranes were demonstrated to allow for an excellent selective separation of monovalent anions in aqueous solution. Furthermore, different types of rGO-SDDS-rGO@QPPO membranes were found to have a good mechanical strength, with a tensile strength up to 66.43 MPa. The membrane (rGO-SDDS-rGO@QPPO-2) also has a low surface electric resistance (2.79 Ω·cm 2 ) and a low water content (14.5%) and swelling rate (4.7%). In addition, the selective separation between Cl - and SO 4 2- of the MGOF membranes could be as high as 36.6%.
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Collaborative-Hybrid Multi-Layer Network Control for Emerging Cyber-Infrastructures
Energy Technology Data Exchange (ETDEWEB)
Lehman, Tom [USC; Ghani, Nasir [UNM; Boyd, Eric [UCAID
2010-08-31
At a high level, there were four basic task areas identified for the Hybrid-MLN project. They are: o Multi-Layer, Multi-Domain, Control Plane Architecture and Implementation, including OSCARS layer2 and InterDomain Adaptation, Integration of LambdaStation and Terapaths with Layer2 dynamic provisioning, Control plane software release, Scheduling, AAA, security architecture, Network Virtualization architecture, Multi-Layer Network Architecture Framework Definition; o Heterogeneous DataPlane Testing; o Simulation; o Project Publications, Reports, and Presentations.
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Finite element analysis of multilayer coextrusion.
Energy Technology Data Exchange (ETDEWEB)
Hopkins, Matthew Morgan; Schunk, Peter Randall; Baer, Thomas A. (Proctor & Gamble Company, West Chester, OH); Mrozek, Randy A. (Army Research Laboratory, Adelphi, MD); Lenhart, Joseph Ludlow (Army Research Laboratory, Adelphi, MD); Rao, Rekha Ranjana; Collins, Robert (Oak Ridge National Laboratory); Mondy, Lisa Ann
2011-09-01
Multilayer coextrusion has become a popular commercial process for producing complex polymeric products from soda bottles to reflective coatings. A numerical model of a multilayer coextrusion process is developed based on a finite element discretization and two different free-surface methods, an arbitrary-Lagrangian-Eulerian (ALE) moving mesh implementation and an Eulerian level set method, to understand the moving boundary problem associated with the polymer-polymer interface. The goal of this work is to have a numerical capability suitable for optimizing and troubleshooting the coextrusion process, circumventing flow instabilities such as ribbing and barring, and reducing variability in layer thickness. Though these instabilities can be both viscous and elastic in nature, for this work a generalized Newtonian description of the fluid is used. Models of varying degrees of complexity are investigated including stability analysis and direct three-dimensional finite element free surface approaches. The results of this work show how critical modeling can be to reduce build test cycles, improve material choices, and guide mold design.
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TAPE CALENDERING MANUFACTURING PROCESS FOR MULTILAYER THIN-FILM SOLID OXIDE FUEL CELLS
Energy Technology Data Exchange (ETDEWEB)
Nguyen Minh; Kurt Montgomery
2004-10-01
This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the Phases I and II under Contract DE-AC26-00NT40705 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Tape Calendering Manufacturing Process For Multilayer Thin-Film Solid Oxide Fuel Cells''. The main objective of this project was to develop the manufacturing process based on tape calendering for multilayer solid oxide fuel cells (SOFC's) using the unitized cell design concept and to demonstrate cell performance under specified operating conditions. Summarized in this report is the development and improvements to multilayer SOFC cells and the unitized cell design. Improvements to the multilayer SOFC cell were made in electrochemical performance, in both the anode and cathode, with cells demonstrating power densities of nearly 0.9 W/cm{sup 2} for 650 C operation and other cell configurations showing greater than 1.0 W/cm{sup 2} at 75% fuel utilization and 800 C. The unitized cell design was matured through design, analysis and development testing to a point that cell operation at greater than 70% fuel utilization was demonstrated at 800 C. The manufacturing process for both the multilayer cell and unitized cell design were assessed and refined, process maps were developed, forming approaches explored, and nondestructive evaluation (NDE) techniques examined.
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High-energy x-ray microscopy with multilayer reflectors (invited)
International Nuclear Information System (INIS)
Underwood, J.H.
1986-01-01
A knowledge of the spatial distribution of the x rays emitted by the hot plasma region is a key element in the study of the physical processes occurring in laser-produced plasmas and complements other diagnostics such as spectroscopy and temporal studies. X-ray microscopy with reflection microscopes offers the most direct means of obtaining this information. Until recently, the two types of microscopes that had been developed for this purpose, the Kirkpatrick--Baez and the Wolter, operated at relatively low energies (about 4--5 keV) and had very little spectral selectivity, relying on filters for coarse spectral resolution. With the development of x-ray reflecting multilayer mirrors, the energy response of such microscopes can be extended to 10 keV or higher, with good spectral selectivity. In addition, it is possible to reduce some of the optical aberrations to obtain improved spatial resolution. This paper describes some of the recent progress in making and evaluating x-ray reflectors, and outlines the optical design considerations for multilayer-coated microscopes. Results from a prototype multilayer K--B microscope are presented
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Formation of oriented membrane multilayers of Na/K-ATPase
International Nuclear Information System (INIS)
Pachence, J.M.; Knott, R.; Edelman, I.S.; Schoenborn, B.P.; Wallace, B.A.
1982-01-01
The isolated membrane-bound enzyme retains its ouabain-sensitive ATP hydrolysis activity, and produces ATP-dependent Na + and K + fluxes when incorporated into phospholipid vesicles. The ultimate goal of this work is to determine its low resolution structure using both X-ray and neutron diffraction. A number of methods were used to impart lamellar stacking order to highly purified pig Na/K-ATPase membranes. Upon partial dehydration, x-ray diffraction from Na/K-ATPase membrane multilayers at 98% relative humidity yielded discrete reflections of 118 A periodicity, diffracting to 1/14.8 A -1 , additionally, continuous diffraction to 1/10 A -1 was obtained. Subjecting the membrane multilayers to high magnetic fields improved the quality of the lamellar diffraction dramatically. Neutron diffraction studies of the partially dehydrated Na/K-ATPase membrane multilayers detected a mosaic spread of 2 0 when the samples were subjected to a magnetic field of 5 Tesla perpendicular to the membrane surface; the reflections were narrower than the camera line width; hence, the lattice disorder has also decreased significantly, although only four orders were measured
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Preliminary investigation of changes in x-ray multilayer optics subjected to high radiation flux
International Nuclear Information System (INIS)
Hockaday, M.P.; Blake, R.L.; Grosso, J.S.; Selph, M.M.; Klein, M.M.; Matuska, W. Jr.; Palmer, M.A.; Liefeld, R.J.
1985-01-01
A variety of metal multilayers was exposed to high x-ray flux using Sandia National Laboratories' PROTO II machine in the gas puff mode. Fluxes incident on the multilayers above 700 MW/cm 2 in total radiation, in nominal 20 ns pulses, were realized. The neon hydrogen- and helium-like resonance lines were used to probe the x-ray reflectivity properties of the multilayers as they underwent change of state during the heating pulse. A fluorescer-fiber optic-streak camera system was used to monitor the changes in x-ray reflectivity as a function of time and irradiance. Preliminary results are presented for a W/C multilayer. Work in progress to model the experiment is discussed. 13 refs., 4 figs
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Multiferroic properties of BiFeO3/BaTiO3 multilayered thin films
International Nuclear Information System (INIS)
Sharma, Savita; Tomar, Monika; Kumar, Ashok; Puri, Nitin K.; Gupta, Vinay
2014-01-01
Multilayered structures of multiferroic BiFeO 3 (BFO) and ferroelectric BaTiO 3 (BTO) have been fabricated using pulsed laser deposition (PLD). Ferromagnetic and ferroelectric properties of the multilayered system (BFO/BTO) have been investigated. It could be inferred that the magnetization increases with the incorporation of BTO buffer layer, which indicates a coupling between the ferroelectric and ferromagnetic orders. Vibrating sample magnetometer (VSM) measurements performed on the prepared multiferroic samples show that the magnetization is significantly increased (M s =56.88 emu/cm 3 ) for the multilayer system with more number of layers (four) keeping the total thickness of the multilayered system constant (350 nm) meanwhile maintaining the sufficiently enhanced ferroelectric properties (P r =29.68 µC/cm 2 )
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Mishra, Nidhi; Yadav, Kuldeep Singh; Rai, Vineet Kumar; Yadav, Narayan Prasad
2017-02-01
Andrographolide (AP), a phytoconstituent of Andrographis paniculata is reported as a potent hepatoprotective agent. However, utility of this molecule is restricted due to its low aqueous solubility, gastric instability and hence low bioavailability. It was aimed to formulate and characterize AP-loaded, natural biopolymer stabilized, multilayered nano-hydrocolloid delivery system. Nanoemulsion (NE) was formulated using layer-by-layer (LbL) technology via electrostatic deposition of chitosan over alginate encrusted o/w NE by ultra-sonication. Improved transparency and stability of NE were observed with increasing sonication time. Best stability was obtained after 20 min sonication and particle size of the multilayered NE was measured in the range of 90.8-167.8 nm. Transmission electron microscopy confirmed the progressive layering of nanosized NE. Higher magnitude of zeta potential (i.e., 22.9 to 31.01 mV) confirmed higher stability and coating of alginate layer over NE surface for the period of 3 months. NE showed strategic release pattern when assessed in vitro in various simulated biological fluids of GIT in timed pattern. Multilayered NE showed significant modulation in liver function test (ALT, ALP, AST, TBIL, DBIL, and liver glycogen) and serum cytokines (TNF-α, IL-6, IL-10, and IL-β) when assessed in vivo in galactosamine-lipopolysaccharide intoxicated mice. In conclusion, the andrographolide engrained multi-layered NE enhanced the solubility, stability and henceforth assured the increased availability in simulated biological fluids. The in vivo study exhibited the significantly improved hepatoprotection by andrographolide when delivered in stable multi-layered NE carrier systems.
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Golova, T. A.; Magerramova, I. A.; Ivanov, S. A.
2018-05-01
Calculation of multilayered plates and covers does not consider anisotropic properties of a construction. Calculation comes down to uniform isotropic covers and definition of one of intense and deformation conditions of constructions. The existing techniques consider work of multilayered designs by means of various coefficients. The article describes the optimized algorithm of operations when designing multilayered plates and covers with filler of various types on the basis of the conducted researches. It is dealt with a development engineering algorithm of calculation of multi-layer constructions of walls. Software is created which allows one to carry out assessment of intense and deformation conditions of constructions of walls.
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International Nuclear Information System (INIS)
Pankov, V.V.; Chernyshev, G.G.; Kozlov, N.E.
1987-01-01
A mathematical model for optimization of multilayer submerged arc welding of frame equipment of power units is constructed. The variation-energy method permits to construct the universal mathematical model for strengthening formation of a single bead; the method is reasonable for simulation of a multilayer welded joint. Minimization of the distance between maximum and minimum layer height of a built-up metal is the necessary condition for qualitative formation of the multilayer joint. One can calculate in real time scale the optimal vector of maximally ten parameters under the multilayer welding condition immediately after change in the grooving width using the developed mathematical model of optimization
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Ferroelectric properties of PZT/BFO multilayer thin films prepared using the sol-gel method.
Jo, Seo-Hyeon; Lee, Sung-Gap; Lee, Young-Hie
2012-01-05
In this study, Pb(Zr0.52Ti0.48)O3/BiFeO3 [PZT/BFO] multilayer thin films were fabricated using the spin-coating method on a Pt(200 nm)/Ti(10 nm)/SiO2(100 nm)/p-Si(100) substrate alternately using BFO and PZT metal alkoxide solutions. The coating-and-heating procedure was repeated several times to form the multilayer thin films. All PZT/BFO multilayer thin films show a void-free, uniform grain structure without the presence of rosette structures. The relative dielectric constant and dielectric loss of the six-coated PZT/BFO [PZT/BFO-6] thin film were approximately 405 and 0.03%, respectively. As the number of coatings increased, the remanent polarization and coercive field increased. The values for the BFO-6 multilayer thin film were 41.3 C/cm2 and 15.1 MV/cm, respectively. The leakage current density of the BFO-6 multilayer thin film at 5 V was 2.52 × 10-7 A/cm2.
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Development of neutron diffuse scattering analysis code by thin film and multilayer film
International Nuclear Information System (INIS)
Soyama, Kazuhiko
2004-01-01
To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering by thin film, roughness of surface of thin film, correlation function, neutron propagation by thin film, diffuse scattering by DWBA theory, measurement model, SDIFFF (neutron diffuse scattering analysis program by thin film) and simulation results are explained. On neutron diffuse scattering by multilayer film, roughness of multilayer film, principle of diffuse scattering, measurement method and simulation examples by MDIFF (neutron diffuse scattering analysis program by multilayer film) are explained. (S.Y.)To research surface structure of thin film and multilayer film by neutron, a neutron diffuse scattering analysis code using DWBA (Distorted-Wave Bron Approximation) principle was developed. Subjects using this code contain the surface and interface properties of solid/solid, solid/liquid, liquid/liquid and gas/liquid, and metal, magnetism and polymer thin film and biomembran. The roughness of surface and interface of substance shows fractal self-similarity and its analytical model is based on DWBA theory by Sinha. The surface and interface properties by diffuse scattering are investigated on the basis of the theoretical model. The calculation values are proved to be agreed with the experimental values. On neutron diffuse scattering
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A Reduced-Order Model for Evaluating the Dynamic Response of Multilayer Plates to Impulsive Loads
2016-04-12
A REDUCED-ORDER MODEL FOR EVALUATING THE DYNAMIC RESPONSE OF MULTILAYER PLATES TO IMPULSIVE LOADS Weiran Jiang, Alyssa Bennett, Nickolas...innovative multilayer materials or structures to optimize the dynamic performance as a mechanism to absorb and spread energy from an impulsive load...models. • Optimizing the structural weight and levels of protection of the multilayer plates with a good combination of materials. Technical Approach 2016
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Anisotropy of heat conduction in Mo/Si multilayers
International Nuclear Information System (INIS)
Medvedev, V. V.; Yakshin, A. E.; Kruijs, R. W. E. van de; Bijkerk, F.; Yang, J.; Schmidt, A. J.; Zoethout, E.
2015-01-01
This paper reports on the studies of anisotropic heat conduction phenomena in Mo/Si multilayers with individual layer thicknesses selected to be smaller than the mean free path of heat carriers. We applied the frequency-domain thermoreflectance technique to characterize the thermal conductivity tensor. While the mechanisms of the cross-plane heat conduction were studied in detail previously, here we focus on the in-plane heat conduction. To analyze the relative contribution of electron transport to the in-plane heat conduction, we applied sheet-resistance measurements. Results of Mo/Si multilayers with variable thickness of the Mo layers indicate that the net in-plane thermal conductivity depends on the microstructure of the Mo layers
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Effect of swift heavy ion-irradiation on Cr/Fe/Ni multilayers
International Nuclear Information System (INIS)
Gupta, Ratnesh; Gupta, Ajay; Avasthi, D.K.; Principi, G.; Tosello, C.
1999-01-01
A multilayer film having overall composition Fe 50 Cr 25 Ni 25 , was irradiated successively by 80 MeV Si ions and Ag ions of 150 and 200 MeV energy. The energy deposited in the multilayer in the form of electronic excitations results in significant modification at the interfaces. The interfacial roughness increases in the system after the irradiations as revealed by X-ray reflectivity measurement. Moessbauer measurements provide evidence of intermixing after the irradiation by 200 MeV Ag ions. Comparison of heavy ion irradiated multilayer has been done with annealed and low energy ion irradiated samples. Results suggest that the phases formed at the interfaces of iron as a result of electronic energy loss are similar to those in the cases of thermal diffusion and keV energy ion beam irradiation
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Magnetoresistance in amorphous NdFeB/FeB compositionally modulated multilayers
International Nuclear Information System (INIS)
Peral, G.; Briones, F.; Vicent, J.L.
1991-01-01
Resistance measurements have been done in amorphous Nd 12 Fe 80 B 8 sputtered films and in amorphous sputtered Nd 26 Fe 68 B 6 /Fe 92 B 8 multilayers between 6 and 150 K with applied magnetic field parallel (LMR) and perpendicular (TMR) up to 7 T. The samples were grown by dc triode sputtering, with nominal unequal (2:1) layer thicknesses. The layered character of the samples have been tested by x-ray diffraction. Longitudinal magnetoresistance (LMR) is positive and transverse magnetoresistance (TMR) is negative. The magnetoresistance values are higher than in amorphous ferromagnets, and multilayering of these alloys produces much larger magnetoresistance values than either alloy alone and there is a strong dependence on the multilayer wavelength. The MR shows a weak temperature dependence in the temperature interval that was investigated
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Thermoelectric characteristics of Pt-silicide/silicon multi-layer structured p-type silicon
International Nuclear Information System (INIS)
Choi, Wonchul; Jun, Dongseok; Kim, Soojung; Shin, Mincheol; Jang, Moongyu
2015-01-01
Electric and thermoelectric properties of silicide/silicon multi-layer structured devices were investigated with the variation of silicide/silicon heterojunction numbers from 3 to 12 layers. For the fabrication of silicide/silicon multi-layered structure, platinum and silicon layers are repeatedly sputtered on the (100) silicon bulk substrate and rapid thermal annealing is carried out for the silicidation. The manufactured devices show ohmic current–voltage (I–V) characteristics. The Seebeck coefficient of bulk Si is evaluated as 195.8 ± 15.3 μV/K at 300 K, whereas the 12 layered silicide/silicon multi-layer structured device is evaluated as 201.8 ± 9.1 μV/K. As the temperature increases to 400 K, the Seebeck coefficient increases to 237.2 ± 4.7 μV/K and 277.0 ± 1.1 μV/K for bulk and 12 layered devices, respectively. The increase of Seebeck coefficient in multi-layered structure is mainly attributed to the electron filtering effect due to the Schottky barrier at Pt-silicide/silicon interface. At 400 K, the thermal conductivity is reduced by about half of magnitude compared to bulk in multi-layered device which shows the efficient suppression of phonon propagation by using Pt-silicide/silicon hetero-junctions. - Highlights: • Silicide/silicon multi-layer structured is proposed for thermoelectric devices. • Electric and thermoelectric properties with the number of layer are investigated. • An increase of Seebeck coefficient is mainly attributed the Schottky barrier. • Phonon propagation is suppressed with the existence of Schottky barrier. • Thermal conductivity is reduced due to the suppression of phonon propagation
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2013-08-23
... DEPARTMENT OF COMMERCE International Trade Administration [A-570-970] Multilayered Wood Flooring... an antidumping duty new shipper review of multilayered wood flooring (``MLWF'') from the People's... of subject merchandise at less than normal value. \\1\\ See Multilayered Wood Flooring From the People...
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High temperature annealing effect on structural and magnetic properties of Ti/Ni multilayers
International Nuclear Information System (INIS)
Bhatt, Pramod; Ganeshan, V.; Reddy, V.R.; Chaudhari, S.M.
2006-01-01
High temperature annealing effect on structural and magnetic properties of Ti/Ni multilayer (ML) up to 600 deg. C have been studied and reported in this paper. Ti/Ni multilayer samples having constant layer thicknesses of 50 A each are deposited on float glass and Si(1 1 1) substrates using electron-beam evaporation technique under ultra-high vacuum (UHV) conditions at room temperatures. The micro-structural parameters and their evolution with temperature for as-deposited as well as annealed multilayer samples up to 600 deg. C in a step of 100 deg. C for 1 h are determined by using X-ray diffraction (XRD) and grazing incidence X-ray reflectivity techniques. The X-ray diffraction pattern recorded at 300 deg. C annealed multilayer sample shows interesting structural transformation (from crystalline to amorphous) because of the solid-state reaction (SSR) and subsequent re-crystallization at higher temperatures of annealing, particularly at ≥400 deg. C due to the formation of TiNi 3 and Ti 2 Ni alloy phases. Sample quality and surface morphology are examined by using atomic force microscopy (AFM) technique for both as-deposited as well as annealed multilayer samples. In addition to this, a temperature dependent dc resistivity measurement is also used to study the structural transformation and subsequent alloy phase formation due to annealing treatment. The corresponding magnetization behavior of multilayer samples after each stage of annealing has been investigated by using Magneto-Optical Kerr Effect (MOKE) technique and results are interpreted in terms of observed micro-structural changes
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Symmetric scrolled packings of multilayered carbon nanoribbons
Savin, A. V.; Korznikova, E. A.; Lobzenko, I. P.; Baimova, Yu. A.; Dmitriev, S. V.
2016-06-01
Scrolled packings of single-layer and multilayer graphene can be used for the creation of supercapacitors, nanopumps, nanofilters, and other nanodevices. The full atomistic simulation of graphene scrolls is restricted to consideration of relatively small systems in small time intervals. To overcome this difficulty, a two-dimensional chain model making possible an efficient calculation of static and dynamic characteristics of nanoribbon scrolls with allowance for the longitudinal and bending stiffness of nanoribbons is proposed. The model is extended to the case of scrolls of multilayer graphene. Possible equilibrium states of symmetric scrolls of multilayer carbon nanotribbons rolled up so that all nanoribbons in the scroll are equivalent are found. Dependences of the number of coils, the inner and outer radii, lowest vibrational eigenfrequencies of rolled packages on the length L of nanoribbons are obtained. It is shown that the lowest vibrational eigenfrequency of a symmetric scroll decreases with a nanoribbon length proportionally to L -1. It is energetically unfavorable for too short nanoribbons to roll up, and their ground state is a stack of plane nanoribbons. With an increasing number k of layers, the nanoribbon length L necessary for creation of symmetric scrolls increases. For a sufficiently small number of layers k and a sufficiently large nanoribbon length L, the scrolled packing has the lowest energy as compared to that of stack of plane nanoribbons and folded structures. The results can be used for development of nanomaterials and nanodevices on the basis of graphene scrolled packings.
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International Nuclear Information System (INIS)
Cao, J.; Song, X.G.; Wu, L.Z.; Qi, J.L.; Feng, J.C.
2012-01-01
The Al/Ni multilayers were characterized and diffusion bonding of TiAl intermetallics to TiC cermets was carried out using the multilayers. The microstructure of Al/Ni multilayers and TiAl/TiC cermet joint was investigated. The layered structures consisting of a Ni 3 (AlTi) layer, a Ni 2 AlTi layer, a (Ni,Al,Ti) layer and a Ni diffusion layer were observed from the interlayer to the TiAl substrate. Only one AlNi 3 layer formed at the multilayer/TiC cermet interface. The reaction behaviour of Al/Ni multilayers was characterized by means of differential scanning calorimeter (DSC) and X-ray diffraction. The initial exothermic peak of the DSC curve was formed due to the formation of Al 3 Ni and Al 3 Ni 2 phases. The reaction sequence of the Al/Ni multilayers was Al 3 Ni → Al 3 Ni 2 → AlNi → AlNi 3 and the final products were AlNi and AlNi 3 phases. The shear strength of the joint was tested and the experimental results suggested that the application of Al/Ni multilayers improved the joining quality. - Highlights: ► Diffusion bonding of TiAl to TiC cermet was realized using Al/Ni multilayer. ► The reaction sequence of the Al/Ni multilayers was Al 3 Ni → Al 3 Ni 2 → AlNi → AlNi 3 . ► The interfacial microstructure of the joint was clarified. ► The application of Al/Ni multilayers improved the joining quality.
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Gold-supported two-dimensional cobalt oxyhydroxide (CoOOH) and multilayer cobalt oxide islands
DEFF Research Database (Denmark)
Fester, Jakob; Walton, Alexander; Li, Zheshen
2017-01-01
In the present study, we investigate the facile conversion of Co-O bilayer islands on a Au(111) surface into preferentially O-Co-O trilayers in an oxygen atmosphere and O-Co-O-Co-O multilayers at elevated temperature. We characterize and compare the island morphologies with scanning tunneling...... microscopy, X-ray photoemission spectroscopy (XPS) and valence band spectroscopy, and show that the cobalt oxidation state changes from Co2+ in bilayers to purely Co3+ in trilayers and a mixture of Co2+ and Co3+ in the multilayer morphology. In contrast to bilayers and multilayers, the trilayer structure...
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A double-multilayer monochromator using a modular design for the Advanced Photon Source
International Nuclear Information System (INIS)
Shu, D.; Yun, W.; Lai, B.; Barraza, J.; Kuzay, T.M.
1994-01-01
A novel double-multilayer monochromator has been designed for the Advanced Photon Source X-ray undulator beamline at Argonne National Laboratory. The monochromator consists of two ultra high-vacuum (UHV) compatible modular vessels, each with a sine-bar driving structure and a water-cooled multilayer holder. A high precision Y-Z stage is used to provide compensating motion for the second multilayer from outside the vacuum chamber so that the monochromator can fix the output monochromatic beam direction and angle during the energy scan in a narrow range. The design details for this monochromator are presented in this paper
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Radiography simulation based on exposure buildup factors for multilayer structures
International Nuclear Information System (INIS)
Marinkovic, Predrag; Pesic, Milan
2009-01-01
Monte Carlo techniques were usually used to study the effect of scattered photons on a radiographic X-ray image. Such approach is accurate, but computer time consuming. On the other hand, the exposure buildup factors can be used as approximate and efficient assessment to account for the scattering of X-rays. This method uses the known radiography parameters to find the resulting detector exposure due to both scattered and un-collided photons. A model for radiography simulation, based on X-ray dose buildup factor, is proposed. This model includes non-uniform attenuation in voxelized object of imaging (patient body tissue). Composition of patient body is considered as a multi-layer structure. Various empirical formulas exist for multi-layer structure calculations and they all calculate multi-layer buildup factors by combining single-layer buildup factors. The proposed model is convenient in cases when more exact techniques (like Monte Carlo) are not economical. (author)
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Development of planar CT system for multi-layer PCB inspection
Energy Technology Data Exchange (ETDEWEB)
Kim, Seung Ho; Youn, Hanbean; Kam, Soohwa; Park, Eunpyeong; Kim, Ho Kyung [Pusan National University, Busan (Korea, Republic of)
2015-05-15
X-ray defect inspection apparatus can be used in the production line to inspect the PCB. However, a simple X-ray radiography cannot discriminate defects from the multi-layer PCBs because the layers of them overlays the defects. To complement this issue, computed tomography (CT) technology is applied to the NDT system which can offer 3-dimensional information of object. However, CT requires hundreds of projection images to examine a single PCB, hence real-time inspection is nearly impossible. In this study, we develop a planar computed tomography (pCT) system appropriate for the multi-layer PCB inspection. For the image reconstruction of planar cross-section images, we use the digital tomosynthesis (DTS) concept in association with the limited angle scanning. and performance characterization of the pCT system for the PCB inspection. The 3-d Fourier characteristics and more quantitative performance, such as contrast, uniformity, depth resolution will be presented. The cross-sectional images of multi-layer PCBs will also be demonstrated.
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Time effects in the thermal annealing of Fe/V multilayers
Borges, J F M
2003-01-01
We report a study on the structural and magnetic properties of iron-vanadium thin films grown in multilayer form and mixed by thermal treatment. The multilayer samples were annealed at 610 deg. C for times ranging from 10 to 540 min. The samples were structurally characterized by means of x-ray diffraction (XRD) and by x-ray absorption spectroscopy (XAS). The magnetic characterization was carried out with a conventional alternating gradient magnetometer (AGM) and by conversion electron Moessbauer spectroscopy (CEMS). The XRD result for the as-deposited multilayer shows a high degree of crystallinity while the CEMS result suggests an abrupt interface, since no significant contribution from vanadium in iron is observed. After the thermal treatment, the results from XRD show a phase transformation of the disordered body-centred-cubic structure (alpha-phase) into a tetragonal structure (sigma-phase) and a subsequent return to the alpha-phase. This alpha-sigma-alpha oscillation is not reported in the literature av...
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Park, Sohyeon; Choi, Daheui; Jeong, Hyejoong; Heo, Jiwoong; Hong, Jinkee
2017-10-02
The ability to control drug loading and release is the most important feature in the development of medical devices. In this research, we prepared a functional nanocoating technology to incorporate a drug-release layer onto a desired substrate. The multilayer films were prepared using chitosan (CHI) and carboxymethyl cellulose (CMC) polysaccharides by the layer-by-layer (LbL) method. By using chemical cross-linking to change the inner structure of the assembled multilayer, we could control the extent of drug loading and release. The cross-linked multilayer film had a porous structure and enhanced water wettability. Interestingly, more of the small-molecule drug was loaded into and released from the non-cross-linked multilayer film, whereas more of the macromolecular drug was loaded into and released from the cross-linked multilayer film. These results indicate that drug loading and release can be easily controlled according to the molecular weight of the desired drug by changing the structure of the film.
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International Nuclear Information System (INIS)
Asahi, T.; Kuramochi, K.; Kawaji, J.; Onoue, T.; Osaka, T.; Saigo, M.
2001-01-01
The effect of amorphous carbon underlayer thickness on the microstructure of the Co/Pd multilayer perpendicular magnetic recording media was investigated. From the magnetic force microscopy observation in the AC-demagnetized state of the Co/Pd multilayer media, the magnetic cluster size was observed to effectively decrease with an increase in carbon underlayer thickness, where the higher coercivity and the higher S/N ratio of the Co/Pd multilayer media were obtained with the thicker underlayer. Furthermore, the distribution of [1 1 1] orientation of FCC-Pd became broader, and the grain size decreased with an increase in the carbon underlayer thickness. These effects caused the magnetic exchange decoupling of Co/Pd multilayer media. We suggested that the change of microstructure was directly related to the surface roughness of the amorphous carbon underlayer
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Localized surface plasmon resonance properties of symmetry-broken Au-ITO-Ag multilayered nanoshells
Lv, Jingwei; Mu, Haiwei; Lu, Xili; Liu, Qiang; Liu, Chao; Sun, Tao; Chu, Paul K.
2018-06-01
The plasmonic properties of symmetry-broken Au-ITO-Ag multilayered nanoshells by shell cutting are studied by the finite element method. The influence of the polarization of incident light and geometrical parameters on the plasmon resonances of the multilayered nanoshells are investigated. The polarization-dependent multiple plasmon resonances appear from the multilayered nanoshells due to symmetry breaking. In nanostructures with a broken symmetry, the localized surface plasmon resonance modes are enhanced resulting in higher order resonances. According to the plasmon hybridization theory, these resonance modes and greater spectral tunability derive from the interactions of an admixture of both primitive and multipolar modes between the inner Au core and outer Ag shell. By changing the radius of the Au core, the extinction resonance modes of the multilayered nanoshells can be easily tuned to the near-infrared region. To elucidate the symmetry-broken effects of multilayered nanoshells, we link the geometrical asymmetry to the asymmetrical distributions of surface charges and demonstrate dipolar and higher order plasmon modes with large associated field enhancements at the edge of the Ag rim. The spectral tunability of the multiple resonance modes from visible to near-infrared is investigated and the unique properties are attractive to applications including angularly selective filtering to biosensing.
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Resistance of poly(ethylene oxide)-silane monolayers to the growth of polyelectrolyte multilayers.
Buron, Cédric C; Callegari, Vincent; Nysten, Bernard; Jonas, Alain M
2007-09-11
The ability of poly(ethylene oxide)-silane (PEO-silane) monolayers grafted onto silicon surfaces to resist the growth of polyelectrolyte multilayers under various pH conditions is assessed for different pairs of polyelectrolytes of varying molar mass. For acidic conditions (pH 3), the PEO-silane monolayers exhibit good polyelectrolyte repellency provided the polyelectrolytes bear no moieties that are able to form hydrogen bonds with the ether groups of the PEO chains. At basic pH, PEO-silane monolayers undergo substantial hydrolysis leading to the formation of negatively charged defects in the monolayers, which then play the role of adsorption sites for the polycation. Once the polycation is adsorbed, multilayer growth ensues. Because this is defect-driven growth, the multilayer is not continuous and is made of blobs or an open network of adsorbed strands. For such conditions, the molar mass of the polyelectrolyte plays a key role, with polyelectrolyte chains of larger molar mass adsorbing on a larger number of defects, resulting in stronger anchoring of the polyelectrolyte complex on the surfaces and faster subsequent growth of the multilayer. For polyelectrolytes of sufficiently low molar mass at pH 9, the growth of the multilayer can nevertheless be prevented for as much as five cycles of deposition.
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Lowry, Troy W.; Hariri, Hanaa; Prommapan, Plengchart; Kusi-Appiah, Aubrey; Vafai, Nicholas; Bienkiewicz, Ewa A.; Van Winkle, David H.; Stagg, Scott M.
2016-01-01
The dynamic self-organization of lipids in biological systems is a highly regulated process that enables the compartmentalization of living systems at micro- and nanoscopic scales. Consequently, quantitative methods for assaying the kinetics of supramolecular remodeling such as vesicle formation from planar lipid bilayers or multilayers are needed to understand cellular self-organization. Here, a new nanotechnology-based method for quantitative measurements of lipid–protein interactions is presented and its suitability for quantifying the membrane binding, inflation, and budding activity of the membrane-remodeling protein Sar1 is demonstrated. Lipid multilayer gratings are printed onto surfaces using nanointaglio and exposed to Sar1, resulting in the inflation of lipid multilayers into unilamellar structures, which can be observed in a label-free manner by monitoring the diffracted light. Local variations in lipid multilayer volume on the surface is used to vary substrate availability in a microarray format. A quantitative model is developed that allows quantification of binding affinity (KD) and kinetics (kon and koff). Importantly, this assay is uniquely capable of quantifying membrane remodeling. Upon Sar1-induced inflation of single bilayers from surface supported multilayers, the semicylindrical grating lines are observed to remodel into semispherical buds when a critical radius of curvature is reached. PMID:26649649
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Synthesis and characterization of Cu–Al–Ni shape memory alloy multilayer thin films
Energy Technology Data Exchange (ETDEWEB)
Gómez-Cortés, J.F. [Dpt. Física Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); San Juan, J., E-mail: jose.sanjuan@ehu.es [Dpt. Física Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain); López, G.A.; Nó, M.L. [Dpt. Física Aplicada II, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo. 644, 48080 Bilbao (Spain)
2013-10-01
Among active materials, shape memory alloys are well recognized for their work output density. Because of that, these alloys have attracted much attention to be used in micro/nano electromechanical systems. In the present work, the electron beam evaporation technique has been used to growth, by a multilayer method, two shape memory alloy thin films with different Cu–Al–Ni composition. Multilayers have been further thermally treated to produce the alloys by solid solution diffusion. The produced multilayers have been characterized and the presence of the martensite phase in the obtained thin films was studied. Furthermore, the influence of two different coatings onto the Si substrates, namely Si/SiO{sub 2} and Si/Si{sub 3}N{sub 4}, was investigated. Mechanically stable, not detaching from the substrates, Cu–Al–Ni shape memory alloy thin films, about 1 micrometre thick, showing a martensitic transformation have been produced. - Highlights: ► Multilayer thin films of Cu–Al–Ni shape memory alloys produced by e-beam evaporation. ► SiN{sub X} 200 nm thick coating is good for high quality Cu–Al–Ni shape memory thin films. ► Thermal treatment renders Cu–Al–Ni multilayer in homogeneous martensite thin film.
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International Nuclear Information System (INIS)
Koike, Katsuhiko; Yamazaki, Fumiharu; Okamura, Tomoyuki; Fukuda, Shin
2007-01-01
An optical filter for plasma display panel (PDP) requires an electromagnetic shield with very high ability. The authors investigated a transparent conductive multilayer coating consisting of silver (Ag) layers and transparent metal oxide layers. The durability of the multilayer sputter coating, including the silver layer, is very sensitive to the surrounding atmosphere. For example, after an exposure test they found discolored points on the multilayer sputter coatings, possibly caused by migration of silver atoms in the silver layers. In their investigation, they modified the top surface of the multilayer sputter coatings with transition metals to improve the corrosion resistance of the multilayer coating. Specifically, they deposited transition metals 0.5-2 nm thick on the top surface of the multilayer coatings by sputtering. They chose indium tin oxide (ITO) as the transparent metal oxide. They applied the multilayer sputter coatings of seven layers to a polyethylene terephthalate (PET) film substrate. A cross-sectional structure of the film with the multilayer coatings is PET film/ITO/Ag/ITO/Ag/ITO/Ag/ITO. They evaluated the corrosion resistance of the films by a salt-water immersion test. In the test, they immersed the film with multilayer coatings into salt water, and then evaluated the appearance, transmittance, and electrical resistance of the multilayer coatings. They investigated several transition metals as the modifying material, and found that titanium and tantalum drastically improved the resistance of the multilayer coatings to the salt-water exposure without a significant decline in transmittance. They also investigated the relation between elapsed time after deposition of the modifying materials and resistance to the salt water. Furthermore, they investigated the effects of a heat treatment and an oxide plasma treatment on resistance to the salt water
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Serena, Thomas E; Carter, Marissa J; Le, Lam T; Sabo, Matthew J; DiMarco, Daniel T
2014-01-01
Venous leg ulcers produce significant clinical and economic burdens on society and often require advanced wound therapy. The purpose of this multicenter, randomized, controlled study is to evaluate the safety and efficacy of one or two applications of dehydrated human amnion/chorion membrane allograft and multilayer compression therapy vs. multilayer compression therapy alone in the treatment of venous leg ulcers. The primary study outcome was the proportion of patients achieving 40% wound closure at 4 weeks. Of the 84 participants enrolled, 53 were randomized to receive allograft and 31 were randomized to the control group of multilayer compression therapy alone. At 4 weeks, 62% in the allograft group and 32% in the control group showed a greater than 40% wound closure (p = 0.005), thus showing a significant difference between the allograft-treated groups and the multilayer compression therapy alone group at the 4-week surrogate endpoint. After 4 weeks, wounds treated with allograft had reduced in size a mean of 48.1% compared with 19.0% for controls. Venous leg ulcers treated with allograft had a significant improvement in healing at 4 weeks compared with multilayer compression therapy alone. © 2014 by the Wound Healing Society.
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The transmission of finite amplitude sound beam in multi-layered biological media
Liu, Xiaozhou; Li, Junlun; Yin, Chang; Gong, Xiufen; Zhang, Dong; Xue, Honghui
2007-02-01
Based on the Khokhlov Zabolotskaya Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media.
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The transmission of finite amplitude sound beam in multi-layered biological media
Energy Technology Data Exchange (ETDEWEB)
Liu, Xiaozhou [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China)]. E-mail: xzliu@nju.edu.cn; Li, Junlun [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Yin, Chang [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Gong, Xiufen [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Zhang, Dong [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Xue, Honghui [Key Lab of Modern Acoustics, Institute of Acoustics, Nanjing University, Nanjing 210093 (China)
2007-02-19
Based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media.
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The transmission of finite amplitude sound beam in multi-layered biological media
International Nuclear Information System (INIS)
Liu, Xiaozhou; Li, Junlun; Yin, Chang; Gong, Xiufen; Zhang, Dong; Xue, Honghui
2007-01-01
Based on the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, a model in the frequency domain is given to describe the transmission of finite amplitude sound beam in multi-layered biological media. Favorable agreement between the theoretical analyses and the measured results shows this approach could effectively describe the transmission of finite amplitude sound wave in multi-layered biological media
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Exciton ionization in multilayer transition-metal dichalcogenides
DEFF Research Database (Denmark)
Pedersen, Thomas Garm; Latini, Simone; Thygesen, Kristian Sommer
2016-01-01
Photodetectors and solar cells based on materials with strongly bound excitons rely crucially on field-assisted exciton ionization. We study the ionization process in multilayer transition-metal dichalcogenides (TMDs) within the Mott-Wannier model incorporating fully the pronounced anisotropy...
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AFFORDABLE MULTI-LAYER CERAMIC (MLC) MANUFACTURING FOR POWER SYSTEMS (AMPS)
Energy Technology Data Exchange (ETDEWEB)
E.A. Barringer, Ph.D.
2002-11-27
McDermott Technology, Inc. (MTI) is attempting to develop high-performance, cost-competitive solid oxide fuel cell (SOFC) power systems. Recognizing the challenges and limitations facing the development of SOFC stacks comprised of electrode-supported cells and metallic interconnects, McDermott Technology, Inc. (MTI) has chosen to pursue an alternate path to commercialization. MTI is developing a multi-layer, co-fired, planar SOFC stack that will provide superior performance and reliability at reduced costs relative to competing designs. The MTI approach combines state-of-the-art SOFC materials with the manufacturing technology and infrastructure established for multi-layer ceramic (MLC) packages for the microelectronics industry. The rationale for using MLC packaging technology is that high quality, low-cost manufacturing has been demonstrated at high volumes. With the proper selection of SOFC materials, implementation of MLC fabrication methods offers unique designs for stacks (cells and interconnects) that are not possible through traditional fabrication methods. The MTI approach eliminates use of metal interconnects and ceramic-metal seals, which are primary sources of stack performance degradation. Co-fired cells are less susceptible to thermal cycling stresses by using material compositions that have closely matched coefficients of thermal expansion between the cell and the interconnect. The development of this SOFC stack technology was initiated in October 1999 under the DOE cosponsored program entitled ''Affordable Multi-layer Ceramic Manufacturing for Power Systems (AMPS)''. The AMPS Program was conducted as a two-phase program: Phase I--Feasibility Assessment (10/99--9/00); and Phase II--Process Development for Co-fired Stacks (10/00-3/02). This report provides a summary of the results from Phase I and a more detailed review of the results for Phase II. Phase I demonstrated the feasibility for fabricating multi-layer, co-fired cells and
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Optical Properties of Multilayer CdSe/POLYMER Structures
Red'Ko, V. P.; Voitenkov, A. I.; Kovalenko, O. E.
The effects of preparation condition, concentration and size of particles upon optical and photoelectrical characteristics of multilayer structures CdSe/polyethylene terephthalate obtained by electron-beam evaporation were investigated.
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Lattice Boltzmann simulation of CO2 reactive transport in network fractured media
Tian, Zhiwei; Wang, Junye
2017-08-01
Carbon dioxide (CO2) geological sequestration plays an important role in mitigating CO2 emissions for climate change. Understanding interactions of the injected CO2 with network fractures and hydrocarbons is key for optimizing and controlling CO2 geological sequestration and evaluating its risks to ground water. However, there is a well-known, difficult process in simulating the dynamic interaction of fracture-matrix, such as dynamic change of matrix porosity, unsaturated processes in rock matrix, and effect of rock mineral properties. In this paper, we develop an explicit model of the fracture-matrix interactions using multilayer bounce-back treatment as a first attempt to simulate CO2 reactive transport in network fractured media through coupling the Dardis's LBM porous model for a new interface treatment. Two kinds of typical fracture networks in porous media are simulated: straight cross network fractures and interleaving network fractures. The reaction rate and porosity distribution are illustrated and well-matched patterns are found. The species concentration distribution and evolution with time steps are also analyzed and compared with different transport properties. The results demonstrate the capability of this model to investigate the complex processes of CO2 geological injection and reactive transport in network fractured media, such as dynamic change of matrix porosity.
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Design of grazing-incidence multilayer supermirrors for hard-X-ray reflectors
DEFF Research Database (Denmark)
Joensen, K. D.; Voutov, P.; Szentgyorgyi, A.
1995-01-01
Extremely broadband grazing-incidence multilayers for hard-X-ray reflection can be obtained by a gradual change of the layer thicknesses down through the structure. Existing approaches for designing similar neutron optics, called supermirrors, are shown to provide respectable performance when...... applied to X-ray multilayers. However, none of these approaches consider the effects of imperfect layer interfaces and absorption in the overlying layers. Adaptations of neutron designs that take these effects into account are presented, and a thorough analysis of two specific applications (a single hard......-X-ray reflector and a hard-X-ray telescope) shows that an improved performance can be obtained. A multilayer whose bilayer thicknesses are given by a power law expression is found to provide the best solution; however, it is only slightly better than some of the adapted neutron designs...
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Kwak, Sanghwa; Haider, Adnan; Gupta, Kailash Chandra; Kim, Sukyoung; Kang, Inn-Kyu
2016-07-01
The dual extrusion electrospinning technique was used to fabricate multilayered 3D scaffolds by stacking microfibrous meshes of poly(lactic acid-co-glycolic acid) (PLGA) in alternate fashion to micro/nano mixed fibrous meshes of PLGA and collagen. To fabricate the multilayered scaffold, 35 wt% solution of PLGA in THF-DMF binary solvent (3:1) and 5 wt% solution of collagen in hexafluoroisopropanol (HFIP) with and without hydroxyapatite nanorods (nHA) were used. The dual and individual electrospinning of PLGA and collagen were carried out at flow rates of 1.0 and 0.5 mL/h, respectively, at an applied voltage of 20 kV. The density of collagen fibers in multilayered scaffolds has controlled the adhesion, proliferation, and osteogenic differentiation of MC3T3-E1 cells. The homogeneous dispersion of glutamic acid-modified hydroxyapatite nanorods (nHA-GA) in collagen solution has improved the osteogenic properties of fabricated multilayered scaffolds. The fabricated multilayered scaffolds were characterized using FT-IR, X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM). The scanning electron microscopy (FE-SEM) was used to evaluate the adhesion and spreads of MC3T3-E1 cells on multilayered scaffolds. The activity of MC3T3-E1 cells on the multilayered scaffolds was evaluated by applying MTT, alkaline phosphatase, Alizarin Red, von Kossa, and cytoskeleton F-actin assaying protocols. The micro/nano fibrous PLGA-Col-HA scaffolds were found to be highly bioactive in comparison to pristine microfibrous PLGA and micro/nano mixed fibrous PLGA and Col scaffolds.
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Thermal variation of magnetization in Ni/V multilayers
International Nuclear Information System (INIS)
Benkirane, K.; Elkabil, R.; Hamdoun, A.; Lassri, M.; Abid, M.; Lassri, H.; Krishnan, R.
2004-01-01
The magnetic properties of Ni/V multilayers, prepared by the RF sputtering method, have been systematically studied by magnetic measurements. The magnetization decreases with a decrease in Ni layer thickness tNi and the analysis of the results at 5K indicates the presence of a dead Ni layer about 12A thick. The effective anisotropy Keff of Ni/V multilayers is obtained using a torque magnetometer. The interface contribution to the magnetic anisotropy is practically negligible. A spin-wave theory has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction Jb, surface exchange interaction JS, and the interlayer coupling strength JI for various Ni layer thicknesses have been obtained
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Nanostructure multilayer dielectric materials for capacitors and insulators
Barbee, Jr., Troy W.; Johnson, Gary W.
1998-04-21
A capacitor is formed of at least two metal conductors having a multilayer dielectric and opposite dielectric-conductor interface layers in between. The multilayer dielectric includes many alternating layers of amorphous zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3). The dielectric-conductor interface layers are engineered for increased voltage breakdown and extended service life. The local interfacial work function is increased to reduce charge injection and thus increase breakdown voltage. Proper material choices can prevent electrochemical reactions and diffusion between the conductor and dielectric. Physical vapor deposition is used to deposit the zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3) in alternating layers to form a nano-laminate.
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DEFF Research Database (Denmark)
Orlov, Alexey A.; Yankovskaya, E. A.; Zhukovsky, Sergei
2014-01-01
We show how to correctly extract the effective permittivity and permeability of plasmonic multilayers in the optical domain. For material parameters retrieval the classical Nicolson-Ross-Weir method is commonly used. However, its direct application leads to spurious zero-permittivity points and f...... and false permeability resonances in the case of total reflection from the slab. We offer a way to overcome this issue and retrieve correct constitutive parameters of plasmonic multilayers...
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Proximity effect in ultrathin Pb/Ag multilayers within the Cooper limit
Bourgeois, O.; Frydman, A.; Dynes, R. C.
2003-01-01
We report on transport and tunneling measurements performed on ultra-thin Pb/Ag (strong coupled superconductor/normal metal) multilayers evaporated by quench condensation. The critical temperature and energy gap of the heterostructures oscillate with addition of each layer, demonstrating the validity of the Cooper limit model in the case of multilayers. We observe excellent agreement with a simple theory for samples with layer thickness larger than 30\\AA . Samples with single layers thinner t...
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Using the Multilayer Free-Surface Flow Model to Solve Wave Problems
Energy Technology Data Exchange (ETDEWEB)
Prokof’ev, V. A., E-mail: ProkofyevVA@vniig.ru [B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG) (Russian Federation)
2017-01-15
A method is presented for changing over from a single-layer shallow-water model to a multilayer model with hydrostatic pressure profile and, then, to a multilayer model with nonhydrostatic pressure profile. The method does not require complex procedures for solving the discrete Poisson’s equation and features high computation efficiency. The results of validating the algorithm against experimental data critical for the numerical dissipation of the numerical scheme are presented. Examples are considered.
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International Nuclear Information System (INIS)
Dueber, C.; Klose, K.J.; Thelen, M.
1991-01-01
With digital multilayer tomography a sequence of projection images is recorded by an image intensifier television system and stored as digital data during a linear run of a layer sequence. Using this data record, tomograms of the examined body region can be computed for any layer thickness by shifts and superimposition of the single projections later at a digital workstation. The qualities of digital and conventional tomograms are basically comparable. A drawback of digital tomography is its lower local resolution (512 x 512 image matrix), advantages are a lower radiation exposure, a shorter patient examination time, and the facilities of digital image processing (later processing, archive setup, transmission). (orig.) [de
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Thin film and multilayer optics for XUV spectral domain (1 nm to 60 nm)
International Nuclear Information System (INIS)
Delmotte, Franck
2010-02-01
The XUV spectral domain (1-60 nm wavelength range) has experienced rapid growth in recent years. On one side, the sources (synchrotron radiation, harmonic generation, x-ray laser, free-electron laser...) require ever more efficient optics, on the other hand, applications (diagnostics of hot plasma, solar physics, x-ray microscopy, EUV lithography, x-ray analysis...) provide new constraints on the design of multilayer stacks. The multilayer mirrors are the only way to achieve efficient optics operating at non-grazing incidence angles in this spectral range. Our work within the team XUV Optics at Laboratoire Charles Fabry de l'Institut d'Optique focuses on the study of materials in thin layers correlated to the study of optical properties of multilayers. The objective is to achieve new multilayer components previously unavailable in the XUV domain, through a better understanding of physical phenomena in these nano-layer stacks. We show through several examples of how we have managed both to improve the performance of multilayer mirrors in a broad spectral range, and secondly, to develop new optical functions: beam splitters, broadband mirrors, dual-band mirrors or phase compensation mirrors. (author)
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Characterizations of multilayer ZnO thin films deposited by sol-gel spin coating technique
Directory of Open Access Journals (Sweden)
M.I. Khan
Full Text Available In this work, zinc oxide (ZnO multilayer thin films are deposited on glass substrate using sol-gel spin coating technique and the effect of these multilayer films on optical, electrical and structural properties are investigated. It is observed that these multilayer films have great impact on the properties of ZnO. X-ray Diffraction (XRD confirms that ZnO has hexagonal wurtzite structure. Scanning Electron Microscopy (SEM showed the crack-free films which have uniformly distributed grains structures. Both micro and nano particles of ZnO are present on thin films. Four point probe measured the electrical properties showed the decreasing trend between the average resistivity and the number of layers. The optical absorption spectra measured using UV–Vis. showed the average transmittance in the visible region of all films is 80% which is good for solar spectra. The performance of the multilayer as transparent conducting material is better than the single layer of ZnO. This work provides a low cost, environment friendly and well abandoned material for solar cells applications. Keywords: Multilayer films, Semiconductor, ZnO, XRD, SEM, Optoelectronic properties
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2012-01-01
We investigated the optical, electrical, structural, and surface properties of roll-to-roll [R2R] sputter-grown flexible IZO/Ag/IZO/Ag [IAIA] multilayer films on polyethylene terephthalate substrates as a function of the top indium zinc oxide [IZO] thickness. It was found that the optical transmittance of the IAIA multilayer was significantly influenced by the top IZO layer thickness, which was grown on identical AIA multilayers. However, the sheet resistance of the IAIA multilayer was maintained between the range 5.01 to 5.1 Ω/square regardless of the top IZO thickness because the sheet resistance of the IAIA multilayer was mainly dependent on the thickness of the Ag layers. Notably, the optimized IAIA multilayer had a constant resistance change (ΔR/R0) under repeated outer bending tests with a radius of 10 mm. The mechanical integrity of the R2R-sputtered IAIA multilayer indicated that hybridization of an IZO and Ag metal layer is a promising flexible electrode scheme for the next-generation flexible optoelectronics. PMID:22222144
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Zhang, Dehai; Xie, Guizhong; Li, Yanqin; Liu, Jianxiu
2015-09-01
The digital speckle correlation method (DSCM) is introduced to solve the challenging problems in the related geometric measurement. Theoretical calculations of strain are deduced using the DSCM. Corresponding strains along x and y directions are obtained from uniaxial tension experiments and digital speckle measurements, using the VCM nondeep drawing multilayer sheet, the VCM deep-drawing multilayer sheet, clad films, nondeep drawing substrate, and deep-drawing substrate sheet as the targeted experimental objects. The results show that the maximum strains along the x direction of the VCM nondeep drawing multilayer sheet, the VCM deep-drawing multilayer sheet, clad film, nondeep drawing substrate, and deep-drawing substrate sheet are 68.473%, 48.632%, 91.632%, 50.784% and 40.068%, respectively, while the maximum strains along the y direction are -2.657%, -15.381%, 2.826%, -9.780% and -7.783%, respectively. The mechanical properties of the VCM multilayer sheet are between those of the substrate and clad film, while mechanical properties of the VCM deep-drawing multilayer sheet are superior to those of the VCM nondeep drawing multi-layer sheet.
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DEFF Research Database (Denmark)
Fotiadis, Panagiotis; Polignano, Michele; Gimenez, Lucas Chavarria
2013-01-01
This paper investigates the potentials of traffic steering in the Radio Resource Control (RRC) Idle state by evaluating the Absolute Priorities (AP) framework in a multilayer Long Term Evolution (LTE) macrocell scenario. Frequency priorities are broadcast on the system information and RRC Idle...... periods are not significantly long. Finally, better alignment between the RRC Connected and Idle mobility procedures is observed, guarantying significant decrease of handovers/reselections and potential battery life savings by minimizing the Inter-Frequency (IF) measurement rate in the RRC Idle....
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Dual-bath electrodeposition of n-type Bi–Te/Bi–Se multilayer thin films
Energy Technology Data Exchange (ETDEWEB)
Matsuoka, Ken; Okuhata, Mitsuaki; Takashiri, Masayuki, E-mail: takashiri@tokai-u.jp
2015-11-15
N-type Bi–Te/Bi–Se multilayer thin films were prepared by dual-bath electrodeposition. We varied the number of layers from 2 to 10 while the total film thickness was maintained at approximately 1 μm. All the multilayer films displayed the X-ray diffraction peaks normally observed from individual Bi{sub 2}Te{sub 3} and Bi{sub 2}Se{sub 3} crystal structures, indicating that both phases coexist in the multilayer. The cross-section of the 10-layer Bi–Te/Bi–Se film was composed of stacked layers with nano-sized grains but the boundaries between the layers were not planar. The Seebeck coefficient was almost constant throughout the entire range of our experiment, but the electrical conductivity of the multilayer thin films increased significantly as the number of layers was increased. This may be because the electron mobility increases as the thickness of each layer is decreased. As a result of the increased electrical conductivity, the power factor also increased with the number of layers. The maximum power factor was 1.44 μW/(cm K{sup 2}) for the 10-layer Bi–Te/Bi–Se film, this was approximately 3 times higher than that of the 2-layer sample. - Highlights: • N-type Bi–Te/Bi–Se multilayer thin films were deposited by electrodeposition. • We employed a dual-bath electrodeposition process for preparing the multilayers. • The Bi–Te/Bi–Se film was composed of stacked layers with nano-sized grains. • The electrical conductivity increased as the number of layers was increased. • The power factor improved by 3 times as the number of layers was increased.
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High spin-polarization in ultrathin Co2MnSi/CoPd multilayers
International Nuclear Information System (INIS)
Galanakis, I.
2015-01-01
Half-metallic Co 2 MnSi finds a broad spectrum of applications in spintronic devices either in the form of thin films or as spacer in multilayers. Using state-of-the-art ab-initio electronic structure calculations we exploit the electronic and magnetic properties of ultrathin Co 2 MnSi/CoPd multilayers. We show that these heterostructures combine high values of spin-polarization at the Co 2 MnSi spacer with the perpendicular magnetic anisotropy of binary compounds such as CoPd. Thus they could find application in spintronic/magnetoelectronic devices. - Highlights: • Ab-initio study of ultrathin Co 2 MnSi/CoPd multilayers. • Large values of spin-polarization at the Fermi are retained. • Route for novel spintronic/magnetoelectronic devices
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Electric Field-Dependent Photoluminescence in Multilayer Transition Metal Dichalcogenides
Stanev, T. K.; Henning, A.; Sangwan, V. K.; Speiser, N.; Stern, N. P.; Lauhon, L. J.; Hersam, M. C.; Wang, K.; Valencia, D.; Charles, J.; Kubis, T. C.
Owing to interlayer coupling, transition metal dichalcogenides (TMDCs) such as MoS2 exhibit strong layer dependence of optical and electronic phenomena such as the band gap and trion and neutral exciton population dynamics. Here, we systematically measure the effect of layer number on the optical response of multilayer MoS2 in an external electric field, observing field and layer number dependent emission energy and photoluminescence intensity. These effects are studied in few (2-6) and bulk (11 +) layered structures at low temperatures. In MoS2\\ the observed layer dependence arises from several mechanisms, including interlayer charge transfer, band structure, Stark Effect, Fermi level changes, screening, and surface effects, so it can be challenging to isolate how these mechanisms impact the observables. Because it behaves like a stack of weakly interacting monolayers rather than multilayer or bulk, ReS2 provides a comparison to traditional TMDCs to help isolate the underlying physical mechanisms dictating the response of multilayers. This work is supported by the National Science Foundation MRSEC program (DMR-1121262), and the 2-DARE Grant (EFRI-1433510). N.P.S. is an Alfred P. Sloan Research Fellow.
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Structural properties of the Chinese air transportation multilayer network
International Nuclear Information System (INIS)
Hong, Chen; Zhang, Jun; Cao, Xian-Bin; Du, Wen-Bo
2016-01-01
Highlights: • We investigate the structural properties of the Chinese air transportation multilayer network (ATMN). • We compare two main types of layers corresponding to major and low-cost airlines. • It is found that small-world property and rich-club effect of the Chinese ATMN are mainly caused by major airlines. - Abstract: Recently multilayer networks are attracting great attention because the properties of many real-world systems cannot be well understood without considering their different layers. In this paper, we investigate the structural properties of the Chinese air transportation multilayer network (ATMN) by progressively merging layers together, where each commercial airline (company) defines a layer. The results show that the high clustering coefficient, short characteristic path length and large collection of reachable destinations of the Chinese ATMN can only emerge when several layers are merged together. Moreover, we compare two main types of layers corresponding to major and low-cost airlines. It is found that the small-world property and the rich-club effect of the Chinese ATMN are mainly caused by those layers corresponding to major airlines. Our work will highlight a better understanding of the Chinese air transportation network.
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X-ray Multilayers and Thin-Shell Substrate Surface-Figure Correction
Windt, David
We propose a comprehensive experimental research program whose two main goals are (a) to improve the performance of hard X-ray multilayer coatings and (b) to develop a high-throughput method to correct mid-frequency surface errors in thin-shell mirror substrates. Achieving these goals will enable the cost-effective construction of light- weight, highly-nested X-ray telescopes having greater observational sensitivity, wider energy coverage, and higher angular resolution than can be achieved at present. The realization of this technology will thus benefit the development of a variety of Explorer- class NASA X-ray astronomy missions now being formulated for both the soft and hard X-ray bands, and will enable the construction of future facility-class X-ray missions that will require both high sensitivity and high resolution. Building on the success of our previous APRA-funded research, we plan to investigate new thin-film growth techniques, new materials, and new aperiodic coating designs in order to develop new hard X-ray multilayers that have higher X-ray reflectance, wider energy response, lower film stress, and good stability, and that can be produced more quickly, at reduced cost. Additionally, we propose to build upon our extensive experience in sub-nm film-thickness control using velocity modulation and masked deposition techniques, and in the recent development of low-roughness, low-stress films grown by reactive sputtering, in order to develop new methods for correcting mid-frequency surface errors in thin-shell mirror substrates using both differential deposition and ion-beam figuring, either alone or in combination. These two surface-correction techniques already being used for sub-nm figuring of precision optics in a variety of disciplines, including diffraction-limited EUV lithography and synchrotron applications requiring sub-micron focusing are ideally suited for controlling mm-scale surface errors in the thin-shell substrates used for astronomical X
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Time-Dependent Thermally-Driven Interfacial Flows in Multilayered Fluid Structures
Haj-Hariri, Hossein; Borhan, A.
1996-01-01
A computational study of thermally-driven convection in multilayered fluid structures will be performed to examine the effect of interactions among deformable fluid-fluid interfaces on the structure of time-dependent flow in these systems. Multilayered fluid structures in two models configurations will be considered: the differentially heated rectangular cavity with a free surface, and the encapsulated cylindrical liquid bridge. An extension of a numerical method developed as part of our recent NASA Fluid Physics grant will be used to account for finite deformations of fluid-fluid interfaces.
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Energy Technology Data Exchange (ETDEWEB)
Ebisawa, T.; Tasaki, S.; Kawai, T.; Akiyoshi, T. [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Achiwa, N.; Hino, M.; Otake, Y.; Funahashi, H.
1996-08-01
The authors have developed cold neutron optics and interferometry using multilayer mirrors. The advantages of the multilayer mirrors are their applicability to long wavelength neutrons and a great variety of the mirror performance. The idea of the present spin interferometry is based on nonmagnetic neutron spin quantum precession using multilayer spin splitters. The equation for polarized neutrons means that the polarized neutrons are equivalent to the coherent superposition of two parallel spin eigenstates. The structure and principle of a multilayer spin splitter are explained, and the nonmagnetic gap layer of the multilayer spin splitter gives rise to neutron spin quantum precession. The performance test of the multilayer spin splitter were made with a new spin interferometer, which is analogous optically to a spin echo system with vertical precession field. The spin interferometers were installed at Kyoto University research reactor and the JRR-3. The testing method and the results are reported. The performance tests on a new phase-spin echo interferometer are described, and its applications to the development of a high resolution spin echo system and a Jamin type cold neutron interferometer are proposed. (K.I.)
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Uhlhorn, R.J.R.; Uhlhorn, R.J.R.; Keizer, Klaas; Burggraaf, Anthonie; Burggraaf, A.J.
1992-01-01
Multilayer diffusion and capillary condensation of propylene on supported γ-alumina films greatly improved the permeability and selectivity. Multilayer diffusion, occurring at relative pressures of 0.4 to 0.8 strongly increased the permeability of 6 times the Knudsen permeability, yielding
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Optimization of multi-layered metallic shield
International Nuclear Information System (INIS)
Ben-Dor, G.; Dubinsky, A.; Elperin, T.
2011-01-01
Research highlights: → We investigated the problem of optimization of a multi-layered metallic shield. → The maximum ballistic limit velocity is a criterion of optimization. → The sequence of materials and the thicknesses of layers in the shield are varied. → The general problem is reduced to the problem of Geometric Programming. → Analytical solutions are obtained for two- and three-layered shields. - Abstract: We investigate the problem of optimization of multi-layered metallic shield whereby the goal is to determine the sequence of materials and the thicknesses of the layers that provide the maximum ballistic limit velocity of the shield. Optimization is performed under the following constraints: fixed areal density of the shield, the upper bound on the total thickness of the shield and the bounds on the thicknesses of the plates manufactured from every material. The problem is reduced to the problem of Geometric Programming which can be solved numerically using known methods. For the most interesting in practice cases of two-layered and three-layered shields the solution is obtained in the explicit analytical form.
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Topological edge modes in multilayer graphene systems
Ge, Lixin
2015-08-10
Plasmons can be supported on graphene sheets as the Dirac electrons oscillate collectively. A tight-binding model for graphene plasmons is a good description as the field confinement in the normal direction is strong. With this model, the topological properties of plasmonic bands in multilayer graphene systems are investigated. The Zak phases of periodic graphene sheet arrays are obtained for different configurations. Analogous to Su-Schrieffer-Heeger (SSH) model in electronic systems, topological edge plasmon modes emerge when two periodic graphene sheet arrays with different Zak phases are connected. Interestingly, the dispersion of these topological edge modes is the same as that in the monolayer graphene and is invariant as the geometric parameters of the structure such as the separation and period change. These plasmonic edge states in multilayer graphene systems can be further tuned by electrical gating or chemical doping. © 2015 Optical Society of America.
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Piezoelectric Multilayer-Stacked Hybrid Actuation/Transduction System
Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor)
2014-01-01
A novel full piezoelectric multilayer stacked hybrid actuation/transduction system. The system demonstrates significantly-enhanced electromechanical performance by utilizing the cooperative contributions of the electromechanical responses of multilayer stacked negative and positive strain components. Both experimental and theoretical studies indicate that for this system, the displacement is over three times that of a same-sized conventional flextensional actuator/transducer. The system consists of at least 2 layers which include electromechanically active components. The layers are arranged such that when electric power is applied, one layer contracts in a transverse direction while the second layer expands in a transverse direction which is perpendicular to the transverse direction of the first layer. An alternate embodiment includes a third layer. In this embodiment, the outer two layers contract in parallel transverse directions while the middle layer expands in a transverse direction which is perpendicular to the transverse direction of the outer layers.
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The reactivity meter and core reactivity
International Nuclear Information System (INIS)
Siltanen, P.
1999-01-01
This paper discussed in depth the point kinetic equations and the characteristics of the point kinetic reactivity meter, particularly for large negative reactivities. From a given input signal representing the neutron flux seen by a detector, the meter computes a value of reactivity in dollars (ρ/β), based on inverse point kinetics. The prompt jump point of view is emphasised. (Author)
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International Nuclear Information System (INIS)
Youn Ki Byoung
1987-01-01
This research thesis reports the fabrication of W/C, Ni/C and Mo/C interferential multi-layer mirrors which can be used in the X-UV domain. They have been manufactured by cathodic pulverisation by using a new system for the in-situ control of the thickness of deposited layers, based on the measurement, sampling and real time integration of the ionic current which goes through the target during the coating process. Different methods (X ray diffraction at different wavelengths, electron microscopy and diffraction, in situ electronic resistivity measurement) have been used to study the main parameters which govern the multi-layer reflectivity: structure, substrate and interface roughness, minimum thickness to be deposited to obtain a continuous layer, number of bi-layers, stacking evenness, rate of absorbent element thickness to the period. Absolute reflectivity measurements have been performed by using short wavelength synchrotron radiation and the S component of polarised soft X rays obtained after double reflection on two parallel multi-layer mirrors oriented according to the Brewster angle. Ferromagnetic properties of Ni/C multi-layers have been studied to investigate fundamental magnetic properties, and to obtain additional information on interface structure [fr
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Chen, Xingyu; Yang, Ming; Liu, Botao; Li, Zhiqiang; Tan, Hong; Li, Jianshu
2017-08-22
Choline phosphate (CP), which is a new zwitterionic molecule, and has the reverse order of phosphate choline (PC) and could bind to the cell membrane though the unique CP-PC interaction. Here we modified a glass surface with multilayer CP molecules using surface-initiated atom-transfer radical polymerization (SI-ATRP) and the ring-opening method. Polymeric brushes of (dimethylamino)ethyl methacrylate (DMAEMA) were synthesized by SI-ATRP from the glass surface. Then the grafted PDMAEMA brushes were used to introduce CP groups to fabricate the multilayer CP molecule modified surface. The protein adsorption experiment and cell culture test were used to evaluate the biocompatibility of the modified surfaces by using human umbilical veinendothelial cells (HUVECs). The protein adsorption results demonstrated that the multilayer CP molecule decorated surface could prevent the adsorption of fibrinogen and serum protein. The adhesion and proliferation of cells were improved significantly on the multilayer CP molecule modified surface. Therefore, the biocompatibility of the material surface could be improved by the modified multilayer CP molecule, which exhibits great potential for biomedical applications, e.g., scaffolds in tissue engineering.
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International Nuclear Information System (INIS)
Shu, Y.; Zou, J.; Ou, G.; Wang, L.; Li, Q.
2011-01-01
Extracellular matrix (ECM), like biomimetic surface modification of titanium implants, is a promising method for improving its biocompatibility. In this paper chitosan (Chi) and heparin (Hep) multilayer was coated on pure titanium using a layer-by-layer (LbL) self-assembly technique. The Hep-Chi multilayer growth was carried out by first depositing a single layer of positively charged poly-L-lysine (PLL) on the NaOH-treated titanium substrate (negatively charged surface), followed by alternate deposition of negatively charged Hep and positively charged Chi, and terminated by an outermost layer of Chi. The multilayer was characterized by DR-FTIR, SEM, and AFM, and osteoblasts were cocultured with the modified titanium and untreated titanium surfaces, respectively, to evaluate their cytocompatibility in vitro. The results confirmed that Hep-Chi multilayer was fabricated gradually on the titanium surface. The Hep-Chi multilayer-coated titanium improved the adhesion, proliferation and differentiation of osteoblasts. Thus, the approach described here may provide a basis for the preparation of modified titanium surfaces for use in dental or orthopedic implants