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1

Laser forward transfer using a sacrificial layer: Influence of the material properties  

International Nuclear Information System (INIS)

The deposition of metal and polymer patterns was achieved with a laser forward transfer method involving a sacrificial release layer. Aluminum, gelatine and methylcellulose pixels were precisely transferred from a donor to a receiver substrate using the UV-laser decomposition of an intermediate triazene polymer layer. The roughness and edge sharpness of the pixels are found to be very dependent on the transfer material. For aluminum, a thick layer of triazene has to be used to get a clean transfer, which remains unclear yet. The applied fluence as well as the triazene thickness are strongly interdependent on the mechanical properties of the transfer layer. This work endeavours some important aspects of the transfer mechanism, and opens the way to further investigations, which are necessary to get a clear understanding of the process

2007-12-15

2

Benefit effort relation of sacrificial layers  

International Nuclear Information System (INIS)

[en] The facilities to influence the interaction between melt and the concrete foundation by a sacrificial layer was investigated by the help of the code SACRI. The results of this investigation show that a relative moderation of the course of the accident can be realized by a simple sacrificial layer. FeO or basalt are suitable sacrificial materials. On principle, the long-term embankment of the melt can be attaind with an insulating casing round the sacrificial bed. This measure would require a considerable effort and has an impact on the containment pressure. (orig./HP)[de] Die Moeglichkeiten, mit einer Opferschicht die Einwirkung der Schmelze auf das Reaktorfundament zu beeinflussen, wurde mit Hilfe des Rechenprogramms SACRI untersucht. Dabei hat sich gezeigt, dass mit einer einfachen Opferschicht eine bedingte Abmilderung des Unfallablaufs erzielt werden kann. Als geeignete Opfermaterialien kommen FeO oder Basalt in Frage. Die langfristige Eindaemmung der Schmelze liesse sich prinzipiell durch Eingrenzung des Opferbetts mit einem Isoliermantel erreichen. Dies wuerde allerdings einen erheblichen Aufwand erfordern und hat Konsequenzen bezueglich des Druckaufbaus im Containment. (orig.)

1983-01-01

3

In-situ deposition of sacrificial layers during ion implantation  

International Nuclear Information System (INIS)

[en] The retained dose of implanted ions is limited by sputtering. It is known that a sacrificial layer deposited prior to ion implantation can lead to an enhanced retained dose. However, a higher ion energy is required to obtain a similar implantation depth due to the stopping of ions in the sacrificial layer. It is desirable to have a sacrificial layer of only a few monolayers thickness which can be renewed after it has been sputtered away. We explain the concept and describe two examples: (i) metal ion implantation using simultaneously a vacuum arc ion source and filtered vacuum arc plasma sources, and (ii) Metal Plasma Immersion Ion Implantation and Deposition (MePIIID). In MePIIID, the target is immersed in a metal or carbon plasma and a negative, repetitively pulsed bias voltage is applied. Ions are implanted when the bias is applied while the sacrificial layer suffers sputtering. Low-energy thin film deposition - repair of the sacrificial layer -- occurs between bias pulses. No foreign atoms are incorporated into the target since the sacrificial film is made of the same ion species as used in the implantation phase

1995-01-01

4

Use of silicon oxynitride as a sacrificial material for microelectromechanical devices  

Energy Technology Data Exchange (ETDEWEB)

The use of silicon oxynitride (SiO.sub.x N.sub.y) as a sacrificial material for forming a microelectromechanical (MEM) device is disclosed. Whereas conventional sacrificial materials such as silicon dioxide and silicate glasses are compressively strained, the composition of silicon oxynitride can be selected to be either tensile-strained or substantially-stress-free. Thus, silicon oxynitride can be used in combination with conventional sacrificial materials to limit an accumulation of compressive stress in a MEM device; or alternately the MEM device can be formed entirely with silicon oxynitride. Advantages to be gained from the use of silicon oxynitride as a sacrificial material for a MEM device include the formation of polysilicon members that are substantially free from residual stress, thereby improving the reliability of the MEM device; an ability to form the MEM device with a higher degree of complexity and more layers of structural polysilicon than would be possible using conventional compressively-strained sacrificial materials; and improved manufacturability resulting from the elimination of wafer distortion that can arise from an excess of accumulated stress in conventional sacrificial materials. The present invention is useful for forming many different types of MEM devices including accelerometers, sensors, motors, switches, coded locks, and flow-control devices, with or without integrated electronic circuitry.

Habermehl, Scott D. (Corrales, NM); Sniegowski, Jeffry J. (Edgewood, NM)

2001-01-01

5

Interaction of dioxyzirconium ceramics with the sacrificial material of the European reactor trap  

International Nuclear Information System (INIS)

[en] The present paper discusses the complications that can arise in using in the core melt trap of the European nuclear reactor being designed a sacrificial material of 40% FeOx-60%SiO2 composition. The investigation of the interaction of zirconium dioxide ceramics with the sacrificial material has permitted the conclusion that at a local baring of the refractory layer its destruction can occur. The addition of neodymium oxide to the melts lowers erosion and excludes regeneration of the ceramics structure. (Authors)

2004-01-01

6

Shadowgraphy investigation of laser-induced forward transfer: Front side and back side ablation of the triazene polymer sacrificial layer  

International Nuclear Information System (INIS)

Thin films of a photodecomposible triazene polymer are used as sacrificial layer for the micro-deposition of sensitive materials by laser-induced forward transfer. To understand the ablation process of this sacrificial layer, the ultraviolet laser ablation of triazene films was investigated by time-resolved shadowgraphy. Irradiation from the film side shows a complete decomposition into gaseous fragments, while ablation through the substrate causes ejection of a solid flyer of polymer. The occurence of the flyer depends on the film thickness as well as on the applied fluence, and a compact flyer is obtaind when these two parameters are optimized

2009-03-01

7

Sacrificial adhesion promotion layers for copper metallization of device structures.  

UK PubMed Central (United Kingdom)

The adhesion of copper films to adjacent device layers including TiN, Ta, and TaN diffusion barriers is a crucial reliability issue for integrated circuits. We report that ultrathin layers of poly(acrylic acid) (PAA) prepared on barrier surfaces or on the native oxide of Si wafers dramatically increase the interfacial adhesion of Cu films deposited by the H2 assisted reduction of bis(2,2,7-trimethyloctane-3,5-dionato)copper in supercritical carbon dioxide. Similar improvements were achieved on Si wafers using a simple vapor phase exposure of the substrate to acrylic acid prior to metallization. The deposited films and the substrate/Cu interfaces were analyzed by X-ray photoelectron spectroscopy (XPS), electron microscopy, atomic force microscopy, and variable-angle spectroscopic ellipsometry. No trace of the adhesion layer was detected at the interface, indicating it was sacrificial at the deposition conditions used. Moreover, the presence and subsequent decomposition of the PAA layer during deposition substantially reduced or eliminated metal oxides at the substrate interface. For depositions on PAA-treated Si wafers, copper was present primarily as Cu0 at the interface and Si was present only as Si0. On PAA-treated Ta substrates, XPS analysis indicated Ta was present primarily as Ta0 at the metallized interface whereas Ta2O5 dominated the interface of samples prepared without the adhesion layers. The technique can be extended to patterned substrates using adsorption of acrylic acid or thermal/UV polymerization of acrylic acid.

Zong Y; Shan X; Watkins JJ

2004-10-01

8

Sacrificial adhesion promotion layers for copper metallization of device structures.  

Science.gov (United States)

The adhesion of copper films to adjacent device layers including TiN, Ta, and TaN diffusion barriers is a crucial reliability issue for integrated circuits. We report that ultrathin layers of poly(acrylic acid) (PAA) prepared on barrier surfaces or on the native oxide of Si wafers dramatically increase the interfacial adhesion of Cu films deposited by the H2 assisted reduction of bis(2,2,7-trimethyloctane-3,5-dionato)copper in supercritical carbon dioxide. Similar improvements were achieved on Si wafers using a simple vapor phase exposure of the substrate to acrylic acid prior to metallization. The deposited films and the substrate/Cu interfaces were analyzed by X-ray photoelectron spectroscopy (XPS), electron microscopy, atomic force microscopy, and variable-angle spectroscopic ellipsometry. No trace of the adhesion layer was detected at the interface, indicating it was sacrificial at the deposition conditions used. Moreover, the presence and subsequent decomposition of the PAA layer during deposition substantially reduced or eliminated metal oxides at the substrate interface. For depositions on PAA-treated Si wafers, copper was present primarily as Cu0 at the interface and Si was present only as Si0. On PAA-treated Ta substrates, XPS analysis indicated Ta was present primarily as Ta0 at the metallized interface whereas Ta2O5 dominated the interface of samples prepared without the adhesion layers. The technique can be extended to patterned substrates using adsorption of acrylic acid or thermal/UV polymerization of acrylic acid. PMID:15461508

Zong, Yinfeng; Shan, Xiaoying; Watkins, James J

2004-10-12

9

Use of Amphoteric Copolymer Films as Sacrificial Layers for Constructing Free-Standing Layer-by-Layer Films  

Directory of Open Access Journals (Sweden)

Full Text Available The present paper reports the use of an amphoteric copolymer, poly(diallylamine-co-maleic acid) (PDAMA), as a component of precursor layers (or sacrificial layers) for constructing free-standing layer-by-layer (LbL) films. A PDAMA-poly(styrenesulfonate) (PSS) film or PDAMA-poly(dimethyldiallylammonium chloride) (PDDA) film was coated on the surface of a quartz slide at pH 4.0 or 8.0, respectively, as a sacrificial layer that can be removed by changing the pH. The surface of the sacrificial layer was further covered with LbL films composed of poly(allylamine hydrochloride) (PAH) and PSS. The PAH-PSS films were released from the substrate upon immersing the film-coated quartz slide in acidic or neutral/basic solution, respectively, as a result of the pH-induced dissolution of the PDAMA-PDDA or PDAMA-PSS sacrificial layer. Thus, PDAMA-based sacrificial layers have been demonstrated to dissolve in both acidic and neutral solutions, depending on the type of counter polymer. The thicknesses of the sacrificial layers and released LbL films are crucial factors for constructing free-standing LbL films. The releasing kinetics also depended on the thickness of the crucial layers. The free-standing PAH-PSS films obtained were stable in water or in air in the dry state. PDAMA-based sacrificial layers may be useful in constructing free-standing LbL films containing biomolecules with limited pH stability.

Baozhen Wang; Yu Tokuda; Koji Tomida; Shigehiro Takahashi; Katsuhiko Sato; Jun-ichi Anzai

2013-01-01

10

Properties of low residual stress silicon oxynitrides used as a sacrificial layer  

Energy Technology Data Exchange (ETDEWEB)

Low residual stress silicon oxynitride thin films are investigated for use as a replacement for silicon dioxide (SiO{sub 2}) as sacrificial layer in surface micromachined microelectrical-mechanical systems (MEMS). It is observed that the level of residual stress in oxynitrides is a function of the nitrogen content in the film. MEMS film stacks are prepared using both SiO{sub 2} and oxynitride sacrificial layers. Wafer bow measurements indicate that wafers processed with oxynitride release layers are significantly flatter. Polycrystalline Si (poly-Si) cantilevers fabricated under the same conditions are observed to be flatter when processed with oxynitride rather than SiO{sub 2} sacrificial layers. These results are attributed to the lower post-processing residual stress of oxynitride compared to SiO{sub 2} and reduced thermal mismatch to poly-Si.

Habermehl, S.D.; Glenzinski, A.K.; Halliburton, W.M.; Sniegowski, J.J.

2000-01-04

11

Reverse transfer of nanostencil patterns using intermediate sacrificial layer and lift-off process  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We propose a new process by which patterns produced by nanostencil lithography can be reversed, so that the final pattern on the substrate has the same contrast (filled or empty) as that of the stencil. In this process, the stencil pattern is first formed on an intermediate sacrificial layer, and th...

Park, C W; Vazquez Mena, O; van den Boogaart, M A F; Brugger, J

12

Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at ...

Costescu, Ruxandra M; Deneke, Christoph; Thurmer, Dominic J; Schmidt, Oliver G

13

Improvement in semiconductor laser printing using a sacrificial protecting layer for organic thin-film transistors fabrication  

Energy Technology Data Exchange (ETDEWEB)

Laser-induced forward transfer (LIFT) has been used to deposit pixels of an organic semiconductor, distyryl-quaterthiophenes (DS4T). The dynamics of the process have been investigated by shadowgraphic imaging for the nanosecond (ns) and picosecond (ps) regime on a time-scale from the laser iradiation to 1.5 {mu}s. The morphology of the deposit has been studied for different conditions. Intermediate sacrificial layer of gold or triazene polymer has been used to trap the incident radiation. Its role is to protect the layer to be transferred from direct irradiation and to provide a mechanical impulse strong enough to eject the material.

Rapp, Ludovic, E-mail: rapp@lp3.univ-mrs.fr [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Cibert, Christophe [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Nenon, Sebastien [CINaM (Centre Interdisciplinaire de Nanoscience de Marseille) - UPR 3118 CNRS - Universite Aix Marseille, Case 913, Campus de Luminy, 13288 Marseille Cedex 09 (France); Alloncle, Anne Patricia [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France); Nagel, Matthias [Empa, Swiss Federal Laboratories for Materials Testing and Reasearch, Laboratory for Functional Polymers, Uberlandstrasse 129, 8600 Duebendorf (Switzerland); Lippert, Thomas [Paul Scherrer Institut, General Energy Research Department, 5232 Villigen PSI (Switzerland); Videlot-Ackermann, Christine; Fages, Frederic [CINaM (Centre Interdisciplinaire de Nanoscience de Marseille) - UPR 3118 CNRS - Universite Aix Marseille, Case 913, Campus de Luminy, 13288 Marseille Cedex 09 (France); Delaporte, Philippe [Laboratoire LP3 (Lasers, Plasma et Procedes Photoniques) - UMR 6182 CNRS - Universite de la Mediterranee - Campus de Luminy C917, 13288 Marseille Cedex 09 (France)

2011-04-01

14

Homeotropic Alignment of a Discotic Liquid Crystal Induced by a Sacrificial Layer  

DEFF Research Database (Denmark)

A convenient method to induce face-on orientation of an alkoxy phtalocyanine discotic mesogen is described. The alignment is imposed by the confinement of the discotic thin films with a top sacrificial polymer layer that is easily removed by washing with a selective solvent, after thermal annealing. Thin films have been characterized by optical and atomic force microscopy, UV-Vis absorption spectroscopy, and grazing incidence wide angle X-ray scattering. The data converge in showing the central role of the sacrificial layer in promoting alignment with the planar molecules orienting parallel to the substrate in an essentially homeotropic arrangement over large lateral length scales and the persistence of this desirable alignment after removal of the layer.

Pouzet, Eric; De Cupere, Vinciane

2009-01-01

15

Methods for making thin layers of crystalline materials  

Energy Technology Data Exchange (ETDEWEB)

Methods for making growth templates for the epitaxial growth of compound semiconductors and other materials are provided. The growth templates are thin layers of single-crystalline materials that are themselves grown epitaxially on a substrate that includes a thin layer of sacrificial material. The thin layer of sacrificial material, which creates a coherent strain in the single-crystalline material as it is grown thereon, includes one or more suspended sections and one or more supported sections.

Lagally, Max G; Paskiewicz, Deborah M; Tanto, Boy

2013-07-23

16

Electroassisted transfer of vertical silicon wire arrays using a sacrificial porous silicon layer.  

UK PubMed Central (United Kingdom)

An electroassisted method is developed to transfer silicon (Si) wire arrays from the Si wafers on which they are grown to other substrates while maintaining their original properties and vertical alignment. First, electroassisted etching is used to form a sacrificial porous Si layer underneath the Si wires. Second, the porous Si layer is separated from the Si wafer by electropolishing, enabling the separation and transfer of the Si wires. The method is further expanded to develop a current-induced metal-assisted chemical etching technique for the facile and rapid synthesis of Si nanowires with axially modulated porosity.

Weisse JM; Lee CH; Kim DR; Cai L; Rao PM; Zheng X

2013-09-01

17

Electroassisted transfer of vertical silicon wire arrays using a sacrificial porous silicon layer.  

Science.gov (United States)

An electroassisted method is developed to transfer silicon (Si) wire arrays from the Si wafers on which they are grown to other substrates while maintaining their original properties and vertical alignment. First, electroassisted etching is used to form a sacrificial porous Si layer underneath the Si wires. Second, the porous Si layer is separated from the Si wafer by electropolishing, enabling the separation and transfer of the Si wires. The method is further expanded to develop a current-induced metal-assisted chemical etching technique for the facile and rapid synthesis of Si nanowires with axially modulated porosity. PMID:23919596

Weisse, Jeffrey M; Lee, Chi Hwan; Kim, Dong Rip; Cai, Lili; Rao, Pratap M; Zheng, Xiaolin

2013-08-13

18

Rolled-Up Nanotech: Illumination-Controlled Hydrofluoric Acid Etching of AlAs Sacrificial Layers  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract The effect of illumination on the hydrofluoric acid etching of AlAs sacrificial layers with systematically varied thicknesses in order to release and roll up InGaAs/GaAs bilayers was studied. For thicknesses of AlAs below 10 nm, there were two etching regimes for the area under illumination: one at low illumination intensities, in which the etching and releasing proceeds as expected and one at higher intensities in which the etching and any releasing are completely suppressed. The “etch suppression” area is well defined by the illumination spot, a feature that can be used to create heterogeneously etched regions with a high degree of control, shown here on patterned samples. Together with the studied self-limitation effect, the technique offers a way to determine the position of rolled-up micro- and nanotubes independently from the predefined lithographic pattern.

Costescu Ruxandra; Deneke Christoph; Thurmer Dominic; Schmidt Oliver

2009-01-01

19

Tribological altruism: A sacrificial layer mechanism of synovial joint lubrication in articular cartilage.  

UK PubMed Central (United Kingdom)

Boundary lubrication is characterized by sliding surfaces separated by a molecularly thin film that reduces friction and wear of the underlying substrate when fluid lubrication cannot be established. In this study, the wear and replenishment rates of articular cartilage were examined in the context of friction coefficient changes, protein loss, and direct imaging of the surface ultrastructure, to determine the efficiency of the boundary lubricant (BL) layer. Depletion of cartilage lubricity occurred with the concomitant loss of surface proteoglycans. Restoration of lubrication by incubation with synovial fluid was much faster than incubation with culture media and isolated superficial zone protein. The replenishment action of the BL layer in articular cartilage was rapid, with the rate of formation exceeding the rate of depletion of the BL layer to effectively protect the tissue from mechanical wear. The obtained results indicate that boundary lubrication in articular cartilage depends in part on a sacrificial layer mechanism. The present study provides insight into the natural mechanisms that minimize wear and resist tissue degeneration over the lifetime of an organism.

Chan SM; Neu CP; DuRaine G; Komvopoulos K; Reddi AH

2012-09-01

20

Development of Sacrificial Material for the Eu-APR1400 Core Catcher  

International Nuclear Information System (INIS)

To increase and diversify the export marker of the Korean nuclear reactor design, we developed the Eu- APR1400 reactor design based on the APR1400 reactor design, satisfying the European nuclear design requirements including the European Utility Requirements (EUR) and the Finnish requirements of YVL. As recommended by both requirements, the so called core-catcher molten core ex-vessel cooling facility was developed to manage a severe accident at the Eu-APR1400 reactor involving a core meltdown and to mitigate its consequences. Usually, sacrificial material (SM), which controls the melt properties and modifies melt conditions favorable to corium retention, can be employed to protect the core catcher body from the molten core and increase its cooling capability. The EPR reactor design (by Areva, France) core catcher consists of the initial corium retention space, the transportation channel and the wide spreading room for core melt cooling. The EPR used two kinds of SM to protect the initial core retention space from core melt and to spread the core melt across the wide spreading room using the different compositions. The VVER (Russia) ensures melt localization in a water-cooled vessel located directly beneath the reactor. SM is used to remove the thermal focusing effect by the layer inversion process between metallic and oxidic melts. The functional requirements for the SM determined for the present core catcher are (1) melting spreading improvement, (2) focusing effect prevention, (3) hydrogen explosion prevention, (4) FP (fission product) release decreasing, and (5) melt recriticality exclusion. The rest of the paper is organized as follows. The next section provides detailed descriptions of the composition of the present SM, which satisfies its functional requirements. Following this, the manufacturing process of the SM is presented

2011-01-01

 
 
 
 
21

Screen printing of a capacitive cantilever-based motion sensor on fabric using a novel sacrificial layer process for smart fabric applications  

Science.gov (United States)

Free-standing cantilevers have been fabricated by screen printing sacrificial and structural layers onto a standard polyester cotton fabric. By printing additional conductive layers, a complete capacitive motion sensor on fabric using only screen printing has been fabricated. This type of free-standing structure cannot currently be fabricated using conventional fabric manufacturing processes. In addition, compared to conventional smart fabric fabrication processes (e.g. weaving and knitting), screen printing offers the advantages of geometric design flexibility and the ability to simultaneously print multiple devices of the same or different designs. Furthermore, a range of active inks exists from the printed electronics industry which can potentially be applied to create many types of smart fabric. Four cantilevers with different lengths have been printed on fabric using a five-layer structure with a sacrificial material underneath the cantilever. The sacrificial layer is subsequently removed at 160 °C for 30 min to achieve a freestanding cantilever above the fabric. Two silver electrodes, one on top of the cantilever and the other on top of the fabric, are used to capacitively detect the movement of the cantilever. In this way, an entirely printed motion sensor is produced on a standard fabric. The motion sensor was initially tested on an electromechanical shaker rig at a low frequency range to examine the linearity and the sensitivity of each design. Then, these sensors were individually attached to a moving human forearm to evaluate more representative results. A commercial accelerometer (Microstrain G-link) was mounted alongside for comparison. The printed sensors have a similar motion response to the commercial accelerometer, demonstrating the potential of a printed smart fabric motion sensor for use in intelligent clothing applications.

Wei, Yang; Torah, Russel; Yang, Kai; Beeby, Steve; Tudor, John

2013-07-01

22

Creation of freestanding wrinkled nano-films with desired deformation properties by controlling the surface morphology of a sacrificial layer  

Science.gov (United States)

Various wrinkle patterns can be formed due to the buckling of a stiff thin film on a compliant substrate. However, most wrinkled films previously reported were fixed on a large deformable substrate and thereby the potential deformability of the film was mechanically constrained by the substrate. In this study, we developed a technique for forming various wrinkled structures on the surface of a sacrificial resin layer. Since the sacrificial layer can be subsequently removed with a solvent, freestanding wrinkled films are created using the sacrificial layer. We found that a wrinkled structure is formed on the surface of the layer by applying a compressive strain to the resin layer at the appropriate moment during the hardening process. The wrinkle pattern depends on the curing time and the timing of the straining in two in-plane orthogonal directions. In addition to conventional stripe and labyrinth patterns by simple uniaxial and equi-biaxial strains, respectively, it was found that independent biaxial strains induce interesting structures, such as an orthogonally ordered wrinkle pattern and a nonsymmetrical buckling structure, in which the stripe array produced by the first straining remains and many finer wrinkles appear in each stripe by the second straining in the orthogonal direction. We conducted tensile experiments for 300-nm-thick freestanding Cu films having these wrinkled structures. The wrinkled nano-films have a variety of mechanical properties: the stripe structure has extremely high deformability (more than 10% strain) and reversibility, the labyrinth structure shows planar isotropic deformation, and the nonsymmetrical buckling structure has an anisotropic modulus and strength. Finite element analysis on the wrinkle structures revealed that the local stress concentration dominates the fracture limits.

Hirakata, Hiroyuki; Maruyama, Tomohiro; Yonezu, Akio; Minoshima, Kohji

2013-05-01

23

A potential method of containing rockburst damage and enhancing safety using a sacrificial layer  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english Rockbursts continue to be a scourge in the mining industry, being responsible for accidents and damage to mining excavations. Although the problem has been present for more than a century, and although much research has been carried out, a solution is still elusive. Determination of, firstly, the demand on the support system imposed in the rockburst and, secondly, the capacity of the support system, cannot be carried out with any confidence, and therefore rockburst suppor (more) t cannot be designed using a conventional design approach. In contrast with the conventional approach, observations of rockburst damage in a mine have revealed a possible alternative approach to rockburst support - sacrificial support. It was observed, in rockburst events, that a support system consisting of concrete panels restrained by grouted cables was destroyed, and the concrete panels were ejected. However, the rock behind the panels remained apparently undamaged and in place. This behaviour reignited the concept of sacrificial support, conceived more than 20 years ago, and which is described in this paper. The remedial solution implemented on the mine, involving cables wrapped over the panels and retained by grouting into boreholes, has been subjected to rockburst loading and has confirmed the validity of the sacrificial support concept. The concept of sacrificial support may be controversial, but is deliberately presented here with the aim of generating discussions and contributions, and with the ultimate aim of improving safety and reducing rockburst damage in mines.

Stacey, T.R.; Rojas, E.

2013-01-01

24

Sodium Exposure Tests on Limestone Concrete Used as Sacrificial Protection Layer in FBR  

International Nuclear Information System (INIS)

Hot sodium coming in contact with structural concrete in case of sodium leak in FBR system cause damage as a result of thermo-chemical attack by burning sodium. In addition, release of free and bound water from concrete leads to generation of hydrogen gas, which is explosive in nature. Hence limestone concrete, as sacrificial layer on the structural concrete in FBR, needs to be qualified. Four concrete blocks of dimension 600 mm x 600 mm x 300 mm with 300 mm x 300 mm x 150 mm cavity were cast and subjected to controlled sodium exposure tests. They have composition of ordinary portland cement, water, fine and coarse aggregate of limestone in the ratio of 1: 0.58: 2.547: 3.817. These blocks were subjected to preliminary inspection by ultrasonic pulse velocity technique and rebound hammer tests. Each block was exposed for 30 minutes to about 12 kg of liquid sodium (? 120 mm liquid column) at 550 deg. C in open air, after which sodium was sucked back from the cavity of the concrete block into a sodium tank. On-line temperature monitoring was carried out at strategic locations of sodium pool and concrete block. After removing sodium from the cavity and cleaning the surfaces, rebound hammer testing was carried out on each concrete block at the same locations where data were taken earlier at pre-exposed stage. The statistical analysis of rebound hammer data revealed that one of the concrete block alone has undergone damage to the extent of 16%. The loss of mass occurred for all the four blocks varied from 0.6 to 2.4% due to release of water during the test duration. Chemical analysis of sodium in concrete samples collected from cavity floor of each block helped in generation of depth profiles of sodium monoxide concentration for each block. From this it is concluded that a bulk penetration of sodium up to 30 mm depth has taken place. However it was also observed that at few local spots, sodium penetrated into concrete up to 50 mm. Cylindrical core samples of 50 mm x 150 mm long were obtained from the exposed cavity and tested for compressive strength and longitudinal ultrasonic pulse velocity (UPV). These are compared with core samples obtained from concrete cubes used as standard reference. The average reduction in UPV and compressive strength were 7% and 29% respectively indicating marginal degradation in mechanical properties of sodium-exposed concrete. (authors)

2006-01-01

25

Amor Sacrificial  

Directory of Open Access Journals (Sweden)

Full Text Available El sacrificio corresponde al amor argumentado. Su ejercicio muchas veces inscrito en el orden sagrado de la cultura no deja de comprometer la participación de la Bemächtigungstrieb", pulsión de apoderamiento. En tanto el sacrificio se rinde al otro para su apaciguamiento o complacencia, por supuesto amor a él, se descubre un desprendimiento de goce, al elevar el mal, la destrucción, al estatuto de soberano bien. La demanda sacrificial atribuida a los dioses introduce la dimensión de falta en estos seres supuestamente omnipotentes. Amor y dioses requieren de su provisión persistente de sacrificios. El cuerpo sometido a la tiranía de la imagen idealizada y exaltada es expuesto a distintos y renovados sacrificios. Y parece que ningún sacrificio fuera satisfactorio. La proclama de guerra puede inscribir de forma preponderante la retórica del sacrificio en su pretensión heroica o de sujeción abominable.

Mario Orozco Guzmán

2011-01-01

26

Platinum ion implantation into single crystal zirconia with a carbon sacrificial layer on the surface  

Energy Technology Data Exchange (ETDEWEB)

Single crystal samples of (100) oriented yttria stabilized cubic zirconia are implanted with Pt ions to doses up to 6 {times} 10{sup 17}/cm{sup 2}. The previous studies showed that the retained Pt dose was too small due to the sputter limit. To overcome this problem, a C film was deposited on the surface of some samples before implantation. The implanted samples were annealed isothermally in air at 400--1,200 C, and were analyzed with RBS-C and TEM. The C-layer has been found to be very effective for protecting the sample surface from sputtering and thus increasing the Pt concentration by a factor of two, up to 33 mol.% Pt. The as-implanted Pt was nonsubstitutional. After annealing at 1,200 C for 1 h, Pt diffused to large depths, and showed a substitutional fraction of about 23%. The detailed TEM measurements on the microstructure and damage of the implanted layer show that after annealing at these temperatures the recovery of ion damage is incomplete. Pt atoms undergo substantial migration concurrently. The Pt at first dissolves in the matrix (though not substitutionally), diffuses and precipitates again at high temperature.

Cao, D.X. [Shanghai Inst. of Nuclear Research (China)]|[Royal Melbourne Inst. of Tech., Melbourne, Victoria (Australia). Microelectronics and Materials Technology Centre]|[Lawrence Berkeley Lab., CA (United States); Chu, J.W.; Pogany, A.P.; Sood, D.K. [Royal Melbourne Inst. of Tech., Melbourne, Victoria (Australia); Brown, I.G. [Lawrence Berkeley Lab., CA (United States)

1995-12-31

27

Buckle-driven delamination of hydrophobic micro-, nano-, and heterostructured membranes without a sacrificial layer.  

UK PubMed Central (United Kingdom)

A fabrication method, based on thin film buckling, is demonstrated to form unique membranes that can be used for applications in optics and biosensing. This method should be applicable to a variety of material systems, which, along with its simplicity and compatibility with different film architectures, allows for widespread implementation.

Larsen GK; Zhao Y

2013-10-01

28

The case for using a sacrificial layer of absorbent insulation in the design of flat and low-sloped roofing  

Science.gov (United States)

Beginning about twenty-five years ago, there was a marked increase in the number of single-ply membrane roof designs used to cover and waterproof flat and low-sloped building roofs. Over the past ten years, there has been a substantial increase in the number of installations of white and more reflective single-ply roof systems, mostly using high density cellular foam insulation in the substrate for insulation. A major factor in the increase in the popularity of these highly insulated and more reflective roof systems is the fact that many governments began offering incentives for building owners to use reflective coverings and better insulated roofs. Now, owing to the energy efficient requirements for the design and construction of new buildings put forth in ASHRAE Standard 90.1, "Energy Standard for Buildings Except Low-Rise Residential Buildings" and the world's apparent desire to be "green" (or at least appear to be), more and more roof designs will include these reflective single-ply membranes, which use the cellular foam insulation boards to meet these requirements. Using a lower density traditional insulation will mean that the roof will have to be very thick to comply, increasing the costs of installation. High density cellular foams do not absorb water until time, vapor pressure drive, UV and thermal shock break down the foam and it becomes more absorbent. This could be 5-7 years or longer, depending on the roof construction and other factors. This means that any water that enters the roof through a breach (leak) in the membrane goes straight into the building. This is not a good consequence since the failure mode of any roof is water entering the building. Keeping the water out of the building is the purpose of the waterproofing layer. This paper reviews the techniques of moisture testing on building roofs and infrared (IR) thermography, and puts forth the idea and reasoning behind having a sacrificial layer of very absorbent insulation installed in every flat and low-sloped roof so that when a breach occurs, it can easily be found, documented and repaired during an annual infrared inspection; as IR is an effective predictive maintenance technique and condition monitoring best practice for roof maintenance.

Stockton, Gregory R.

2013-05-01

29

Improvement of Thickness Uniformity of Silicon on Insulator Layer by Numerically Controlled Sacrificial Oxidation Using Atmospheric-Pressure Plasma with Electrode Array System  

Science.gov (United States)

Recently, silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) have attracted great interest from manufacturers of semiconductor devices because of their excellent electrical characteristics. According to International Technology Roadmap for Semiconductors 2007, a very uniform surface Si layer will be required in a few years; however, no production method has been identified. To achieve the required uniformity in surface Si layer thickness, a new method of numerically controlled sacrificial oxidation using atmospheric-pressure plasma was developed. This paper demonstrates a new electrode array system developed for rapid processing. A very uniform oxide with a peak-to-valley (PV) of 0.13 nm was obtained; the relationship of oxide thickness versus oxidation time is shown.

Kamisaka, Shohei; Yoshinaga, Keinosuke; Sano, Yasuhisa; Mimura, Hidekazu; Matsuyama, Satoshi; Yamauchi, Kazuto

2010-08-01

30

Selection of sacrificial material to be applied in WWER-1000 corium catcher  

International Nuclear Information System (INIS)

Calculating-theoretical analysis of the required properties system of potential materials for the use as buffer material in WWER-1000 corium catcher was done. From the findings of the analysis Al2O3 and Fe2O3 were recommended as basic applicants. With regard to noted each by itself advantages and disadvantages the solid solutions formed by Al2O3 and Fe2O3 are of interest to practical implementation. Results of the evaluations are supported by the investigations into phase diagrams and reactions of active zone melt with oxide solutions based on the Al2O3 - Fe2O3 system

2002-01-01

31

Composition and process for post-etch removal of photoresist and/or sacrificial anti-reflective material deposited on a substrate  

UK PubMed Central (United Kingdom)

A composition and process for removing photoresist and/or sacrificial anti-reflective coating (SARC) materials from a substrate having such material(s) thereon. The composition includes a base component, such as a quaternary ammonium base in combination with an alkali or alkaline earth base, or alternatively a strong base in combination with an oxidant. The composition may be utilized in aqueous medium, e.g., with chelator, surfactant, and/or co-solvent species, to achieve high-efficiency removal of photoresist and/or SARC materials in the manufacture of integrated circuitry, without adverse effect on metal species on the substrate, such as copper, aluminum and/or cobalt alloys, and without damage to SiOC-based dielectric materials employed in the semiconductor architecture.

RATH MELISSA K BERNHARD DAVID

32

COMPOSITION AND PROCESS FOR POST-ETCH REMOVAL OF PHOTORESISTAND/OR SACRIFICIAL ANTI-REFLECTIVE MATERIAL DEPOSITED ON A SUBSTRATE  

UK PubMed Central (United Kingdom)

A composition and process for removing photoresist and/or sacrificial anti- reflective coating (SARC) materials from a substrate having such material(s) thereon. The composition includes a base component, such as a quaternary ammonium base in combination with an alkali or alkaline earth base, or alternatively a strong base in combination with an oxidant. The composition may be utilized in aqueous medium, e.g., with chelator, surfactant, and/or c o- solvent species, to achieve high-efficiency removal of photoresist and/or SA RC materials in the manufacture of integrated circuitry, without adverse effect on metal species on the substrate, such as copper, aluminum and/or cobalt alloys, and without damage to SiOC-based dielectric materials employed in th e semiconductor architecture.

BAUM THOMAS H; KORZENSKI MICHAEL B; BERNHARD DAVID D; RATH MELISSA K; MINSEK DAVID

33

Composite sacrificial anodes for offshore structures  

Energy Technology Data Exchange (ETDEWEB)

An updated version of sacrificial anodes for cathodic protection of structures immersed in seawater was recently patented. The anode, constructed in two anodic materials (aluminum alloy on the inside and magnesium alloy on the surface), offers significant reductions in weight and cost. These reductions are due to the highly protective calcareous deposit that forms on the immersed structure when these anodes are used. Characteristics of the deposit and anode performance are reported.

Rossi, S.; Bonora, P.L.; Pasinetti, R.; Benedetti, L. [Univ. of Trento (Italy); Draghetti, M. [AGIP Off Shore, Milan (Italy); Sacco, E. [AGIP DIRA, Ravenna (Italy)

1996-02-01

34

Method to fabricate layered material compositions  

Energy Technology Data Exchange (ETDEWEB)

A new class of processes suited to the fabrication of layered material compositions is disclosed. Layered material compositions are typically three-dimensional structures which can be decomposed into a stack of structured layers. The best known examples are the photonic lattices. The present invention combines the characteristic features of photolithography and chemical-mechanical polishing to permit the direct and facile fabrication of, e.g., photonic lattices having photonic bandgaps in the 0.1-20.mu. spectral range.

Fleming, James G. (Albuquerque, NM); Lin, Shawn-Yu (Albuquerque, NM)

2002-01-01

35

Large scale soil processing tool for use with a preformed sacrificial guide  

UK PubMed Central (United Kingdom)

A method is provided for centering and guiding a large diameter soil processing tool. A sacrificial guide is formed by using a small diameter soil processing tool to form a soil-cement column having a relatively hard outer section and a relatively soft center section. The relatively hard outer section is utilized to guide the large diameter soil processing tool. In one embodiment, the soft central region of the sacrificial guide is left in place and the pilot of the large tool carries an auger that simply drills through the central portion of the sacrificial guide. In a second embodiment, the sacrificial guide is hollow and the large tool need not have an auger at the tip of its pilot.The large tool advances downwardly through the sacrificial guide and, as it advances downwardly, the large tool breaks up the sacrificial guide and the sacrificial guide particles ultimately form a portion of the soil-cement column formed by the large soil processing tool. The method facilitates the use of soil processing tools having diameters of 8 to 20 feet, for example. Large volumes of subterranean material may be hardened or solidified by using an array of the sacrificial guides to precisely control and center the large processing tool so that the large quantities of subterranean material such as utilized to support an airport runway may be processed efficiently with the invention. The method is also usable with soil processing tools of any diameter.

SCHELLHORN VERNE L

36

KAPOOL experiments to simulate molten corium - sacrificial concrete interaction  

Energy Technology Data Exchange (ETDEWEB)

In future Light Water Reactors special devices (core catchers) might be required to prevent containment failure by basement erosion after reactor pressure vessel melt-through during a core meltdown accident. In the planned European Pressurized Reactor (EPR) the core melt is retained in the reactor cavity for {approx} 1 h to pick up late melts after the failure of the reactor pressure vessel. The reactor cavity is protected by a layer of sacrificial concrete and closed by a melt gate at the bottom towards the spreading compartment. After erosion of the sacrificial concrete and melt-through of the gate the core melt should be distributed homogeneously into the spreading compartment. There the melt is cooled by flooding with water. The knowledge of the sacrificial concrete erosion phase in the reactor cavity is essential for the severe accident assessment. Several KAPOOL experiments have been performed to investigate the erosion of two possible compositions of sacrificial concretes using alumina-iron thermite melts as a simulant for the core melt. Erosion rates as a function of the melt temperature and the inhomogeneity of the melt front are presented in this paper. (authors)

Eppinger, B.; Fieg, G.; Tromm, W. [Forschungszentrum Karlsruhe, Institute fur Kern-und Energietechnik, Karlsruhe (Germany)

2001-07-01

37

Thin film of Poly(acrylic acid-co-allyl acrylate) as a Sacrificial Protective Layer for Hydrophilic Self Cleaning Glass  

Directory of Open Access Journals (Sweden)

Full Text Available Poly(acrylic acid-co-allyl acrylate) statistical copolymers were synthesized in a controlled manner in two steps: first tert.butyl acrylate and allyl acrylate were polymerized via atom transfer radical polymerization (ATRP) and afterwords the tert.butyl protective groups were removed via hydrolysis. Samples of self cleaning glass (SCG) were coated with thin films of poly(acrylic acid-co-allyl acrylate) and cross-linked afterwards by UV irradiation (in the presence of a photoinitiator and an accelerator). Solution cast thin films were transparent and homogeneous before and after UV cross-linking. The irradiated samples were found to be hydrophilic (? < 20°) and water insoluble. The coating prevented the spontaneous hydrophobization of the SCG by residual silicon exhaled from the sealing material. The TiO2 photocatalyst that covers the glass surface was found to strip the protective coating. The rate of the photooxidation process was measured by IR spectroscopy. The real field performance of the protective coating was also tested.

J?nis Lejnieks; Ahmed Mourran; Walter Tillmann; Helmut Keul; Martin Möller

2010-01-01

38

Innovative design and material solutions of thermal contact layers for high heat flux applications in fusion devices  

International Nuclear Information System (INIS)

One difficulty associated with the design and development of sacrificial plasma facing components that have to handle the high heat and particle fluxes in ITER is achieving the necessary contact conductance between the plasma protection material and the high-conductivity substrate in contact with the coolant. This paper presents a novel bond idea which is proposed as one of the options for the sacrificial energy dump targets located at the bottom of the divertor legs. The bonded joint in this design concept provides thermal and electrical contact between the armour and the cooled sub-structure while promoting remote, in-situ maintenance repair and an easy replaceability of the armour part without disturbing the cooling pipes or rewelding neutron irradiated materials. To provide reliable and demountable adhesion, the bond consists of a metal alloy, treated in the semi-solid phase so that it leads to a fine dispersion of a globular solid phase into a liquid matrix (rheocast process). This thermal bond layer would normally operate in the solid state but could be brought reversibly to the semi-solid state during the armour replacement simply by heating it slightly above its solidus temperature. Material and design options are discussed in this paper. Possible methods of installation and removal are described, and lifetime considerations are addressed. In order to validate this concept within the ITER time-frame, a R ampersand D programme must be rapidly implemented.

1994-01-01

39

Nano transfer and nanoreplication using deterministically grown sacrificial nanotemplates  

Energy Technology Data Exchange (ETDEWEB)

Methods, manufactures, machines and compositions are described for nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates. An apparatus, includes a substrate and a nanoconduit material coupled to a surface of the substrate. The substrate defines an aperture and the nanoconduit material defines a nanoconduit that is i) contiguous with the aperture and ii) aligned substantially non-parallel to a plane defined by the surface of the substrate.

Melechko, Anatoli V. (Oak Ridge, TN); McKnight, Timothy E. (Greenback, TN); Guillorn, Michael A. (Ithaca, NY); Ilic, Bojan (Ithaca, NY); Merkulov, Vladimir I. (Knoxville, TX); Doktycz, Mitchel J. (Knoxville, TN); Lowndes, Douglas H. (Knoxville, TN); Simpson, Michael L. (Knoxville, TN)

2012-03-27

40

Atomic Layer Thermopile Materials: Physics and Application  

Directory of Open Access Journals (Sweden)

Full Text Available New types of thermoelectric materials characterized by highly anisotropic Fermi surfaces and thus anisotropic Seebeck coefficients are reviewed. Early studies revealed that there is an induced voltage in high TC oxide superconductors when the surface of the films is exposed to short light pulses. Subsequent investigations proved that the effect is due to anisotropic components of the Seebeck tensor, and the type of materials is referred to atomic layer thermopile (ALT). Our recent studies indicate that multilayer thin films at the nanoscale demonstrate enhanced ALT properties. This is in agreement with the prediction in seeking the larger figure of merit (ZT) thermoelectric materials in nanostructures. The study of ALT materials provides both deep insight of anisotropic transport property of these materials and at the same time potential materials for applications, such as light detector and microcooler. By measuring the ALT properties under various perturbations, it is found that the information on anisotropic transport properties can be provided. The information sometimes is not easily obtained by other tools due to the nanoscale phase coexistence in these materials. Also, some remained open questions and future development in this research direction have been well discussed.

P. X. Zhang; H.-U. Habermeier

2008-01-01

 
 
 
 
41

Radionuclide separations using pillared layered materials  

International Nuclear Information System (INIS)

This is the final report of a two-year Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Pillared Layered Materials (PLMs) are layered inorganic ion exchangers propped apart by metal oxide pillars. PLMs have been synthesized to sorb strontium from liquid nuclear wastes. A study that compared over 60 sorbers for their ability to sorb strontium from Hanford simulants showed that PLMs were the best sorbers; strontium distribution coefficients (SrKd) > 20000 mL/g were obtained. In addition, PLMs showed a high degree of selectivity for strontium over cesium, transition metals, lanthanides and actinides. The sorption of strontium is, however, inhibited by complexants (EDTA); SrKd values drop to d values for Sr2+ and Ba2+ show a strong pH dependence; Kd values increase to >104 above pH 12. The general surface complexation mechanism explains the sorption of these cations on PLMs

1998-01-01

42

Nanomanufacturing : nano-structured materials made layer-by-layer.  

Energy Technology Data Exchange (ETDEWEB)

Large-scale, high-throughput production of nano-structured materials (i.e. nanomanufacturing) is a strategic area in manufacturing, with markets projected to exceed $1T by 2015. Nanomanufacturing is still in its infancy; process/product developments are costly and only touch on potential opportunities enabled by growing nanoscience discoveries. The greatest promise for high-volume manufacturing lies in age-old coating and imprinting operations. For materials with tailored nm-scale structure, imprinting/embossing must be achieved at high speeds (roll-to-roll) and/or over large areas (batch operation) with feature sizes less than 100 nm. Dispersion coatings with nanoparticles can also tailor structure through self- or directed-assembly. Layering films structured with these processes have tremendous potential for efficient manufacturing of microelectronics, photovoltaics and other topical nano-structured devices. This project is designed to perform the requisite R and D to bring Sandia's technology base in computational mechanics to bear on this scale-up problem. Project focus is enforced by addressing a promising imprinting process currently being commercialized.

Cox, James V.; Cheng, Shengfeng; Grest, Gary Stephen; Tjiptowidjojo, Kristianto (University of New Mexico); Reedy, Earl David, Jr.; Fan, Hongyou; Schunk, Peter Randall; Chandross, Michael Evan; Roberts, Scott A.

2011-10-01

43

Layered Atom Arrangements in Complex Materials  

Energy Technology Data Exchange (ETDEWEB)

In this report, we develop an atom layer stacking model to describe systematically the crystal structures of complex materials. To illustrate the concepts, we consider a sequence of oxide compounds in which the metal cations progress in oxidation state from monovalent (M{sup 1+}) to tetravalent (M{sup 4+}). We use concepts relating to geometric subdivisions of a triangular atom net to describe the layered atom patterns in these compounds (concepts originally proposed by Shuichi Iida). We demonstrate that as a function of increasing oxidation state (from M{sup 1+} to M{sup 4+}), the layer stacking motifs used to generate each successive structure (specifically, motifs along a 3 symmetry axis), progress through the following sequence: MMO, MO, M{sub r}O, MO{sub r/s}O{sub u/v}, MOO (where M and O represent fully dense triangular atom nets and r/s and u/v are fractions used to describe partially filled triangular atom nets). We also develop complete crystallographic descriptions for the compounds in our oxidation sequence using trigonal space group R{bar 3}.

K.E. Sikafus; R.W.Grimes; S.M.Corish; A.R. Cleave; M.Tang; C.R.Stanek; B.P. Uberuaga; J.A.Valdez

2005-04-15

44

Nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates  

Energy Technology Data Exchange (ETDEWEB)

Methods, manufactures, machines and compositions are described for nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates. A method includes depositing a catalyst particle on a surface of a substrate to define a deterministically located position; growing an aligned elongated nanostructure on the substrate, an end of the aligned elongated nanostructure coupled to the substrate at the deterministically located position; coating the aligned elongated nanostructure with a conduit material; removing a portion of the conduit material to expose the catalyst particle; removing the catalyst particle; and removing the elongated nanostructure to define a nanoconduit.

Melechko, Anatoli V. (Oak Ridge, TN); McKnight, Timothy E. (Greenback, TN), Guillorn, Michael A. (Ithaca, NY); Ilic, Bojan (Ithaca, NY); Merkulov, Vladimir I. (Knoxville, TN); Doktycz, Mitchel J. (Knoxville, TN); Lowndes, Douglas H. (Knoxville, TN); Simpson, Michael L. (Knoxville, TN)

2011-05-17

45

Radionuclide separations using pillared layered materials  

Energy Technology Data Exchange (ETDEWEB)

This is the final report of a two-year Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Pillared Layered Materials (PLMs) are layered inorganic ion exchangers propped apart by metal oxide pillars. PLMs have been synthesized to sorb strontium from liquid nuclear wastes. A study that compared over 60 sorbers for their ability to sorb strontium from Hanford simulants showed that PLMs were the best sorbers; strontium distribution coefficients ({sup Sr}K{sub d}) > 20000 mL/g were obtained. In addition, PLMs showed a high degree of selectivity for strontium over cesium, transition metals, lanthanides and actinides. The sorption of strontium is, however, inhibited by complexants (EDTA); {sup Sr}K{sub d} values drop to <20 mL/g when they are present. The most promising PLMs were the Cr, Ti, Zr, and Si pillared tantalum tungstate. The K{sub d} values for Sr{sup 2+} and Ba{sup 2+} show a strong pH dependence; K{sub d} values increase to >10{sup 4} above pH 12. The general surface complexation mechanism explains the sorption of these cations on PLMs.

Schroeder, N.C.; Wade, K.L.; Morgan, D.M. [and others

1998-12-31

46

Sacrificial plastic mold with electroplatable base  

Energy Technology Data Exchange (ETDEWEB)

A sacrificial plastic mold having an electroplatable backing is provided. One embodiment consists of the infusion of a softened or molten thermoplastic through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale molding tool contacting the porous metal substrate. Upon demolding, the porous metal substrate will be embedded within the thermoplastic and will project a plastic structure with features determined by the mold tool. This plastic structure, in turn, provides a sacrificial plastic mold mechanically bonded to the porous metal substrate which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved to leave the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

Domeier, Linda A. (Danville, CA); Hruby, Jill M. (Livermore, CA); Morales, Alfredo M. (Livermore, CA)

2002-01-01

47

Sacrificial Plastic Mold With Electroplatable Base  

Energy Technology Data Exchange (ETDEWEB)

A sacrificial plastic mold having an electroplatable backing is provided. One embodiment consists of the infusion of a softened or molten thermoplastic through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale molding tool contacting the porous metal substrate. Upon demolding, the porous metal substrate will be embedded within the thermoplastic and will project a plastic structure with features determined by the mold tool. This plastic structure, in turn, provides a sacrificial plastic mold mechanically bonded to the porous metal substrate which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved to leave the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

Domeier, Linda A. (Danville, CA); Hruby, Jill M. (Livermore, CA); Morales, Alfredo M. (Livermore, CA)

2005-08-16

48

Redox buffered hydrofluoric acid etchant for the reduction of galvanic attack during release etching of MEMS devices having noble material films  

Science.gov (United States)

Etchant solutions comprising a redox buffer can be used during the release etch step to reduce damage to the structural layers of a MEMS device that has noble material films. A preferred redox buffer comprises a soluble thiophosphoric acid, ester, or salt that maintains the electrochemical potential of the etchant solution at a level that prevents oxidation of the structural material. Therefore, the redox buffer preferentially oxidizes in place of the structural material. The sacrificial redox buffer thereby protects the exposed structural layers while permitting the dissolution of sacrificial oxide layers during the release etch.

Hankins, Matthew G. (Albuquerque, NM)

2009-10-06

49

Quantifying the Stacking Registry Matching in Layered Materials  

CERN Multimedia

A detailed account of a recently developed method [Marom et al., Phys. Rev. Lett. 105, 046801 (2010)] to quantify the registry mismatch in layered materials is presented. The registry index, which was originally defined for planar hexagonal boron-nitride, is extended to treat graphitic systems and generalized to describe multi-layered nanotubes. It is shown that using simple geometric considerations it is possible to capture the complex physical features of interlayer sliding in layered materials. The intuitive nature of the presented model and the efficiency of the related computations suggest that the method can be used as a powerful characterization tool for interlayer interactions in complex layered systems.

Hod, Oded

2010-01-01

50

Use of polyelectrolyte complexes and multilayers from polymers and nanoparticles to create sacrificial bonds between surfaces.  

UK PubMed Central (United Kingdom)

In this study, particle polyelectrolyte complexes (PPECs) were formed by mixing cationic polyacrylamide (CPAM) and silica nanoparticles using the jet mixing technique. Within certain limits, the size of the formed PPECs could be controlled. The aim was to prepare PPECs with embedded sacrificial bonds, similar to those found in bones. Examination of PPEC adsorption to silica model surfaces indicated that smaller PPECs adsorbed to a higher level than larger ones, due to the higher diffusion speed of smaller complexes. Adsorption studies of the same components as in the PPECs, but arranged in multilayers, that is, particle polyelectrolyte multilayers (PPEMs), indicated a stable, gradual build-up of material on the surface with smaller nanoparticles, whereas PPEMs comprising elongated nanoparticles appeared to be more loosely adsorbed onto the surface when the nanoparticles were in the outer layer, due to repulsive forces within the adsorbed layer. The AFM colloidal probe technique was used to study the interaction between surfaces treated with PPECs, multilayers, or polyelectrolyte complexes (PECs). The results showed that the expected long-range disentanglement could be achieved with PPECs but that the pull-off forces were generally low. Treatment with PPEMs comprising the same polymer and nanoparticle components produced higher pull-off values, together with disentanglement behaviour, possibly due to better contact between the surfaces. Adhesion experiments with polymer PECs showed significantly higher pull-off values than with the PPECs, probably due to polymer interdiffusion across the surface boundary.

Ankerfors C; Johansson E; Pettersson T; Wågberg L

2013-02-01

51

Anisotropic layers with through-thickness thermal and material variations  

Energy Technology Data Exchange (ETDEWEB)

The thermoelastic problem of an inhomogeneous anisotropic layer with material properties that vary smoothly through the thickness is examined. The problem is solved via a semiinverse technique, relying on the assumptions of the simply-connectedness of the body. The solution is applicable to the analysis of materials with chemical composition gradients and/or temperature-dependent material properties. 14 refs.

Ferrari, M. (California Univ., Berkeley (United States))

1992-09-01

52

FABRICATION OF A VASCULAR SYSTEM USING SACRIFICIAL STRUCTURES  

UK PubMed Central (United Kingdom)

The first aspect of the present invention is directed to a method of producing a vascular network preform (VNP). This method involves forming a network of elongate fibers and at least one elongate structure from a sacrificial material. The diameter of the elongate structure is greater than that of the elongate fibers. The network of elongate fibers is placed in contact with at least one elongate structure either following or during forming the network of elongate fibers or forming the at least one elongate structure. A matrix is applied around the network of elongate fibers, in contact with the at least one elongate structure. The network of elongate fibers and elongate structure, within the matrix is sacrificed to form a preform. The resulting preform contains a vascular network of fine diameter tubes in contact with at least one elongate passage having a diameter greater than that of the fine diameter tubes. The resulting solid preform and methods of using it are also disclosed.

BELLAN LEON M; CRAIGHEAD HAROLD; SPECTOR JASON A

53

Corrosion control acceptance criteria for sacrificial anode type, cathodic protection systems (user guide)  

Science.gov (United States)

The Army currently operates and maintains more than 20,000 underground storage tanks and over 3000 miles of underground gas pipelines, all of which require some form of corrosion control. Cathodic protection is one method of corrosion control used to prevent corrosion-induced leaks when a steel structure is exposed to an aggressive soil. The corrosion control acceptance criteria for sacrificial anode type CP systems provides guidelines for the DEH/DPW cathodic protection installation inspectors whose responsibilities are to ensure that the materials and equipment specified are delivered to the job site and subsequently installed in accordance with the engineering drawings and specifications. The sacrificial anode CP acceptance criteria includes all components for the sacrificial anode system such as insulated conductors, anodes, anode backfills, and auxiliary equipment. The sacrificial anode CP acceptance criteria is composed of a checklist that lists each component and that contains a space for the inspector to either check 'yes' or 'no' to indicate whether the component complies with the job specifications. In some cases, the inspector must measure and record physical dimensions or electrical output and compare the measurements to standards shown in attached tables.

Hock, Vincent F.; Noble, Michael; McLeod, Malcolm E.

1994-07-01

54

Method for depositing layers of high quality semiconductor material  

Energy Technology Data Exchange (ETDEWEB)

Plasma deposition of substantially amorphous semiconductor materials is carried out under a set of deposition parameters which are selected so that the process operates near the amorphous/microcrystalline threshold. This threshold varies as a function of the thickness of the depositing semiconductor layer; and, deposition parameters, such as diluent gas concentrations, must be adjusted as a function of layer thickness. Also, this threshold varies as a function of the composition of the depositing layer, and in those instances where the layer composition is profiled throughout its thickness, deposition parameters must be adjusted accordingly so as to maintain the amorphous/microcrystalline threshold.

Guha, Subhendu (Troy, MI); Yang, Chi C. (Troy, MI)

2001-08-14

55

Examples of material solutions in bimetallic layered castings  

Directory of Open Access Journals (Sweden)

Full Text Available In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer). The bearing part of bimetallic layered casting is typical foundry material i.e. pearlitic grey cast iron, whereas working part (layer) is depending on accepted variant plates of alloy steels sort X6Cr13, X12Cr13, X10CrNi18-8 and X2CrNiMoN22-5-3. The ratio of thickness between bearing and working part is 8:1. The verification of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing), structure and macro- and microhardness researches.

T. Wróbela; M. Cholewa; S. Tenerowicz

2011-01-01

56

Novel material properties of strained-layer superlattices  

International Nuclear Information System (INIS)

Strained-layer superlattices (SLS's) are high quality structures grown from lattice-mismatched semiconductor materials. Recent Sandia studies have demonstrated that a variety of SLS material properties can be tailored through the flexible choice of layer materials and thicknesses and through the use of quantum size effects, zone folding effects, and strain effects. The use of strained layers in SLS's allows these structures to exhibit a number of novel features. Examples of these features include: independently variable band gap and lattice constant using mismatched ternaries; strain-induced band gap shifts; and strain-modified effective masses. These features provide the opportunity for a variety of fundamental and applied materials studies using SLS systems.

1985-01-01

57

Novel material properties of strained-layer superlattices  

Energy Technology Data Exchange (ETDEWEB)

Strained-layer superlattices (SLS's) are high quality structures grown from lattice-mismatched semiconductor materials. Recent Sandia studies have demonstrated that a variety of SLS material properties can be tailored through the flexible choice of layer materials and thicknesses and through the use of quantum size effects, zone folding effects, and strain effects. The use of strained layers in SLS's allows these structures to exhibit a number of novel features. Examples of these features include: independently variable band gap and lattice constant using mismatched ternaries; strain-induced band gap shifts; and strain-modified effective masses. These features provide the opportunity for a variety of fundamental and applied materials studies using SLS systems.

Osbourn, G.C.

1985-05-01

58

Contact mechanics of layered elastic materials: experiment and theory  

International Nuclear Information System (INIS)

This paper reports an experimental and theoretical investigation of the indentation of a layered elastic solid, with special reference to the surface force apparatus (SFA). The contacting surfaces of the SFA comprise a 3-layer material: a thin mica surface layer on a thicker epoxy layer supported by a thick silica substrate. An existing finite element analysis of the deformation of ideal mica/epoxy/silica surfaces used in the SFA is adapted to compare with the experimental measurements of the variation of contact size with load, both with and without adhesion at the interface. This is in marked difference to the Johnson, Kendall and Roberts (JKR) theory for homogeneous solids. Experiments and finite element calculations were also carried out on the elastic indentation of a thin (5.5 ?m) layer of mica on a very thick layer of epoxy (>100 ?m). As input data for the calculations, the elastic moduli of the mica and epoxy were measured in separate indentation experiments. The stiffness of a layered solid can be expressed by an 'effective modulus' Ee*, which has been deduced from the experimental measurements and compared with the theoretical values with fair success. The work of adhesion is commonly measured in the SFA by observing the 'pull-off force' to separate the surfaces. The theory shows that, for a layered solid, the pull-force can vary significantly from the JKR value for a homogeneous solid. In particular, it was found that the mica surface energy, ?sv, measured by SFA experiments using crossed cylinders of mean radius R, where the materials are layered and the mica/mica adhesion is high, can vary with the pull-off force Fp according to Fp/4?R sv p/2?R, and for this particular experiment was given as ?sv = Fp/3.5 ?R as compared with ?sv = Fp/3?R for homogeneous materials.

2007-10-07

59

Thermodynamics of sacrificial deoxidation of refractory metals  

International Nuclear Information System (INIS)

Sacrificial deoxidation via suboxide evaporation at high temperature and vacuum is one of the most important techniques for the purification of many refractory metals. A theoretical thermodynamic approach has been attempted to assess and examine the deoxidation tendencies of refractory metals of groups IV and V. Based on the thermodynamic data available for gaseous suboxides and reported or estimated values of oxygen activities in the metals, vapour pressures of suboxides have been calculated and plotted as a function of temperature and oxygen content of the metal. From these data it has been possible to estimate: (1) the extent of deoxidation, (2) the vaporization loss of metal during deoxidation, and (3) the rate of deoxidation. Calculations have also been made for ternary systems such as Nb-Zr-O and Ta-Hf-O. The calculated values are compared with the reported values based on the experimental observations. (author)

1974-01-01

60

Epitaxial Growth of GaN-based LEDs on Simple Sacrificial Substrates  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to produce alternative substrate technologies for GaN-based LEDs by developing an ALD interlayer of Al{sub 2}O{sub 3} on sacrificial substrates such as ZnO and Si. A sacrificial substrate is used for device growth that can easily be removed using a wet chemical etchant leaving only the thin GaN epi-layer. After substrate removal, the GaN LED chip can then be mounted in several different ways to a metal heat sink/reflector and light extraction techniques can then be applied to the chip and compared for performance. Success in this work will lead to high efficiency LED devices with a simple low cost fabrication method and high product yield as stated by DOE goals for its solid state lighting portfolio.

Ian Ferguson; Chris Summers

2009-12-31

 
 
 
 
61

Incorporating microorganisms into polymer layers provides bioinspired functional living materials.  

UK PubMed Central (United Kingdom)

Artificial two-dimensional biological habitats were prepared from porous polymer layers and inoculated with the fungus Penicillium roqueforti to provide a living material. Such composites of classical industrial ingredients and living microorganisms can provide a novel form of functional or smart materials with capability for evolutionary adaptation. This allows realization of most complex responses to environmental stimuli. As a conceptual design, we prepared a material surface with self-cleaning capability when subjected to standardized food spill. Fungal growth and reproduction were observed in between two specifically adapted polymer layers. Gas exchange for breathing and transport of nutrient through a nano-porous top layer allowed selective intake of food whilst limiting the microorganism to dwell exclusively in between a confined, well-enclosed area of the material. We demonstrated a design of such living materials and showed both active (eating) and waiting (dormant, hibernation) states with additional recovery for reinitiation of a new active state by observing the metabolic activity over two full nutrition cycles of the living material (active, hibernation, reactivation). This novel class of living materials can be expected to provide nonclassical solutions in consumer goods such as packaging, indoor surfaces, and in biotechnology.

Gerber LC; Koehler FM; Grass RN; Stark WJ

2012-01-01

62

Incorporating microorganisms into polymer layers provides bioinspired functional living materials.  

Science.gov (United States)

Artificial two-dimensional biological habitats were prepared from porous polymer layers and inoculated with the fungus Penicillium roqueforti to provide a living material. Such composites of classical industrial ingredients and living microorganisms can provide a novel form of functional or smart materials with capability for evolutionary adaptation. This allows realization of most complex responses to environmental stimuli. As a conceptual design, we prepared a material surface with self-cleaning capability when subjected to standardized food spill. Fungal growth and reproduction were observed in between two specifically adapted polymer layers. Gas exchange for breathing and transport of nutrient through a nano-porous top layer allowed selective intake of food whilst limiting the microorganism to dwell exclusively in between a confined, well-enclosed area of the material. We demonstrated a design of such living materials and showed both active (eating) and waiting (dormant, hibernation) states with additional recovery for reinitiation of a new active state by observing the metabolic activity over two full nutrition cycles of the living material (active, hibernation, reactivation). This novel class of living materials can be expected to provide nonclassical solutions in consumer goods such as packaging, indoor surfaces, and in biotechnology. PMID:22198770

Gerber, Lukas C; Koehler, Fabian M; Grass, Robert N; Stark, Wendelin J

2011-12-22

63

Ultra low thermal conductivity in layered disordered crystalline materials  

Science.gov (United States)

This dissertation presents an alternative route to achieve ultralow thermal conductivity in a dense solid. Thin films of disordered layered crystalline materials were deposited using Modulated Elemental Reactants (MER) method. Cross-plane thermal conductivity was measured using Time-Domain Thermo Reflectance (TDTR) method; elastic properties were investigated using picosecond acoustics. The results are applied to reducing the thermal conductivity in misfit layer materials and multilayers containing disordered layered crystalline materials. The cross-plane thermal conductivity of thin films of WSe2 is as small as 0.05 W m-1 K-1 at room temperature, 30 times smaller than the c-axis thermal conductivity of single-crystal WSe2 and a factor of 6 smaller than the predicted minimum thermal conductivity for this material. The ultralow thermal conductivity is attributed to the anisotropic bonding of the layered WSe2 and orientational disorder in the stacking of well-crystallized WSe2 sheets along the direction perpendicular to the surface. Disordering of the layered structure by ion bombardment increases the thermal conductivity. I measured the room-temperature, cross-plane thermal conductivities and longitudinal speeds of sound of misfit-layer dichalcogenide films [(PbSe) m (TSe2)n] i (T = W or Mo, m = 1-5, n = 1-5) synthesized by the MER. The thermal conductivities of these nanoscale layered materials are 5--6 times lower than the predicted minimum thermal conductivity ?min of PbSe. Thermal conductivity decreases with increasing content of the main source of anisotropy in the sample, the layered chalcogenide, and it is largely unaffected by variations in superlattice period. I investigated the lower limit to the lattice thermal conductivity of Bi2Te3 and related materials using thin films synthesized by MER. The thermal conductivities of single layer films of Bi2Te 3, Bi2Te3 and Sb-doped Bi2Te 3 and multilayer films of (Bi2Te3)m(TiTe 2)n and [(BixSb1-x)2Te 3]m(TiTe2)n are measured by TDTR; the thermal conductivity data are compared to a Debye-Callaway model of heat transport by acoustic phonons. The homogeneous nanocrystalline films have average grains sizes 30layers as thin as 2 nm. In the limit of small grain size or layer thickness, the thermal conductivity of Bi2Te3 approaches the predicted minimum thermal conductivity of 0.31 W m-1 K-1. The dependence of the thermal conductivity on grain size is in good agreement with the Debye-Callaway model. The use of alloy (Bi,Sb)2Te3 layers further reduces the thermal conductivity of the nanoscale layers to as low as 0.20 W m-1 K -1.

Chiritescu, Catalin

64

Nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates  

Energy Technology Data Exchange (ETDEWEB)

Methods, manufactures, machines and compositions are described for nanotransfer and nanoreplication using deterministically grown sacrificial nanotemplates. An apparatus, includes a substrate and a nanoreplicant structure coupled to a surface of the substrate.

Melechko, Anatoli V. (Oak Ridge, TN); McKnight, Timothy E. (Greenback, TN); Guillorn, Michael A. (Ithaca, NY); Ilic, Bojan (Ithaca, NY); Merkulov, Vladimir I. (Knoxville, TN); Doktycz, Mitchel J. (Knoxville, TN); Lowndes, Douglas H. (Knoxville, TN); Simpson, Michael L. (Knoxville, TN)

2011-08-23

65

Sacrificial bonds and hidden length in biomaterials -- a kinetic description of strength and toughness in bone  

Science.gov (United States)

Sacrificial bonds and hidden length in structural molecules account for the greatly increased fracture toughness of biological materials compared to synthetic materials without such structural features, by providing a molecular-scale mechanism of energy dissipation. One example of occurrence of sacrificial bonds and hidden length is in the polymeric glue connection between collagen fibrils in animal bone. In this talk, we propose a simple kinetic model that describes the breakage of sacrificial bonds and the revelation of hidden length, based on Bell's theory. We postulate a master equation governing the rates of bond breakage and formation, at the mean-field level, allowing for the number of bonds and hidden lengths to take up non-integer values between successive, discrete bond-breakage events. This enables us to predict the mechanical behavior of a quasi-one-dimensional ensemble of polymers at different stretching rates. We find that both the rupture peak heights and maximum stretching distance increase with the stretching rate. In addition, our theory naturally permits the possibility of self-healing in such biological structures.

Lieou, Charles K. C.; Elbanna, Ahmed E.; Carlson, Jean M.

2013-03-01

66

Water-Based Layer-by-Layer Surface Chemical Modification of Biomimetic Materials: Oil Repellency.  

UK PubMed Central (United Kingdom)

Biomimetic materials possessing hierarchical surface roughness thrive when complementary terminal chemical functionality is introduced. However, incorporating terminal functionality on the biomimetic material is the challenge, especially, when its roughness needs to be preserved. Hence, we report surface chemical modification of biomimetic materials through water-based layer-by-layer deposition. The amine terminated biomimetic replica PDMS-replica(Silica/NH2) was prepared by treating silica-modified replica (i.e., PDMS-replica(Silica)) with the aqueous solution of branched ethoxylated polyethylenimine (EPEI). Next, -CF3 terminal PDMS-replica(Silica/NH2/CF3) was obtained by treating PDMS-replica(Silica/NH2) with the aqueous solution of phosphate ester fluorosurfactant. PDMS-replica(Silica/NH2/CF3) showed superhydrophobicity (advancing ?water ? 140°) and high oil repellency (advancing ?oil ? 110°). X-ray photoelectron spectroscopy (XPS) revealed well-organized terminal -CF3 groups present on the PDMS-replica(Silica/NH2/CF3) surface. During the process of layer-by-layer deposition, the surface topography was monitored using scanning electron microscopy (SEM). This method could be extended to get desired terminal chemical functionality on the biomimetic materials which would furnish interesting surface properties in air or under water.

Ghosh N; Singh AV; Vaidya AA

2013-09-01

67

Water-Based Layer-by-Layer Surface Chemical Modification of Biomimetic Materials: Oil Repellency.  

Science.gov (United States)

Biomimetic materials possessing hierarchical surface roughness thrive when complementary terminal chemical functionality is introduced. However, incorporating terminal functionality on the biomimetic material is the challenge, especially, when its roughness needs to be preserved. Hence, we report surface chemical modification of biomimetic materials through water-based layer-by-layer deposition. The amine terminated biomimetic replica PDMS-replica(Silica/NH2) was prepared by treating silica-modified replica (i.e., PDMS-replica(Silica)) with the aqueous solution of branched ethoxylated polyethylenimine (EPEI). Next, -CF3 terminal PDMS-replica(Silica/NH2/CF3) was obtained by treating PDMS-replica(Silica/NH2) with the aqueous solution of phosphate ester fluorosurfactant. PDMS-replica(Silica/NH2/CF3) showed superhydrophobicity (advancing ?water ? 140°) and high oil repellency (advancing ?oil ? 110°). X-ray photoelectron spectroscopy (XPS) revealed well-organized terminal -CF3 groups present on the PDMS-replica(Silica/NH2/CF3) surface. During the process of layer-by-layer deposition, the surface topography was monitored using scanning electron microscopy (SEM). This method could be extended to get desired terminal chemical functionality on the biomimetic materials which would furnish interesting surface properties in air or under water. PMID:23942547

Ghosh, Nilmoni; Singh, Amit Vikram; Vaidya, Ashish Anant

2013-09-09

68

Investigation into conditions of producing two-layer materials with the surface layer of titanium carbide-steel  

International Nuclear Information System (INIS)

The possibility is studied of the production of iron-based twin-layer materials with addition of 1, 2, 3% Cu having a surface layer made up of titanium carbide - steel through the method of the simultaneous pressing and sintering together with the hot-pressing of the sintered layer to the sintered basic material. The strength of the layer coupling increases with a higher copper content and lower pressing force applied to the basic material. Thermal treatment enhances the layer hardness and practically does not effect on the layer coupling

1976-01-01

69

Study of materials for using at waste layer in repositories  

International Nuclear Information System (INIS)

This research has an objective to characterize Brazilian clays and to implant a data base containing the information obtained form tests and suppliers. Such information will allow to buy and and to select optimum material for its utilization in the stuffing layer. Brazilian suppliers were contacted for obtaining information and samples, the various clays were tested and these tests comprehend the following: identification of the mineral constituents, determination of the compaction curve as function of the humidity, hydraulic conductivity, humidity and organic material contents, cationic exchange capacity, specific surface, and etc

2009-10-02

70

Sacrificial template method of fabricating a nanotube  

Science.gov (United States)

Methods of fabricating uniform nanotubes are described in which nanotubes were synthesized as sheaths over nanowire templates, such as using a chemical vapor deposition process. For example, single-crystalline zinc oxide (ZnO) nanowires are utilized as templates over which gallium nitride (GaN) is epitaxially grown. The ZnO templates are then removed, such as by thermal reduction and evaporation. The completed single-crystalline GaN nanotubes preferably have inner diameters ranging from 30 nm to 200 nm, and wall thicknesses between 5 and 50 nm. Transmission electron microscopy studies show that the resultant nanotubes are single-crystalline with a wurtzite structure, and are oriented along the direction. The present invention exemplifies single-crystalline nanotubes of materials with a non-layered crystal structure. Similar "epitaxial-casting" approaches could be used to produce arrays and single-crystalline nanotubes of other solid materials and semiconductors. Furthermore, the fabrication of multi-sheath nanotubes are described as well as nanotubes having multiple longitudinal segments.

Yang, Peidong (Berkeley, CA); He, Rongrui (Berkeley, CA); Goldberger, Joshua (Berkeley, CA); Fan, Rong (El Cerrito, CA); Wu, Yi-Ying (Albany, CA); Li, Deyu (Albany, CA); Majumdar, Arun (Orinda, CA)

2007-05-01

71

Sacrificial template method of fabricating a nanotube  

Energy Technology Data Exchange (ETDEWEB)

Methods of fabricating uniform nanotubes are described in which nanotubes were synthesized as sheaths over nanowire templates, such as using a chemical vapor deposition process. For example, single-crystalline zinc oxide (ZnO) nanowires are utilized as templates over which gallium nitride (GaN) is epitaxially grown. The ZnO templates are then removed, such as by thermal reduction and evaporation. The completed single-crystalline GaN nanotubes preferably have inner diameters ranging from 30 nm to 200 nm, and wall thicknesses between 5 and 50 nm. Transmission electron microscopy studies show that the resultant nanotubes are single-crystalline with a wurtzite structure, and are oriented along the <001> direction. The present invention exemplifies single-crystalline nanotubes of materials with a non-layered crystal structure. Similar "epitaxial-casting" approaches could be used to produce arrays and single-crystalline nanotubes of other solid materials and semiconductors. Furthermore, the fabrication of multi-sheath nanotubes are described as well as nanotubes having multiple longitudinal segments.

Yang, Peidong (Berkeley, CA); He, Rongrui (Berkeley, CA); Goldberger, Joshua (Berkeley, CA); Fan, Rong (El Cerrito, CA); Wu, Yi-Ying (Albany, CA); Li, Deyu (Albany, CA); Majumdar, Arun (Orinda, CA)

2007-05-01

72

Application of sacrificial concrete for the retention and conditioning of molten corium in the EPR core melt retention concept  

International Nuclear Information System (INIS)

The core melt stabilisation concept of the EPR involves an ex-vessel MCCI phase with sacrificial concrete for the retention and conditioning of molten corium before and after spreading. Both MCCI phases are simulated with the computer code COSACO, developed by Siemens/KWU. A brief overview of the main features of the code is given together with the results of a parametric study performed for the conservative assumption of a stepwise melt release from the RPV. This study demonstrates that the addition of sacrificial concrete in the reactor pit is an adequate means (i) to achieve a sufficient retention period and (ii) to oxidise all Zr initially present in the melt. For the spreading compartment, COSACO calculations predict a fully oxidised melt at the end of the MCCI. Its liquidus temperature, as confirmed by supplementary DTA-tests, is about 1850 C, and therefore significantly below the initial value of 2400 C. It is further demonstrated that the erosion of the provided sacrificial concrete will result in a density difference of about 2 Mg/m3 between the oxidic and metallic melt and thus in a stable layer inversion. These results justify the choice made for the composition of the sacrificial concrete. (orig.)

73

Application of sacrificial concrete for the retention and conditioning of molten corium in the EPR core melt retention concept  

Energy Technology Data Exchange (ETDEWEB)

The core melt stabilisation concept of the EPR involves an ex-vessel MCCI phase with sacrificial concrete for the retention and conditioning of molten corium before and after spreading. Both MCCI phases are simulated with the computer code COSACO, developed by Siemens/KWU. A brief overview of the main features of the code is given together with the results of a parametric study performed for the conservative assumption of a stepwise melt release from the RPV. This study demonstrates that the addition of sacrificial concrete in the reactor pit is an adequate means (i) to achieve a sufficient retention period and (ii) to oxidise all Zr initially present in the melt. For the spreading compartment, COSACO calculations predict a fully oxidised melt at the end of the MCCI. Its liquidus temperature, as confirmed by supplementary DTA-tests, is about 1850 C, and therefore significantly below the initial value of 2400 C. It is further demonstrated that the erosion of the provided sacrificial concrete will result in a density difference of about 2 Mg/m{sup 3} between the oxidic and metallic melt and thus in a stable layer inversion. These results justify the choice made for the composition of the sacrificial concrete. (orig.)

Nie, M. [Siemens AG KWU, Erlangen (Germany)

2000-05-01

74

Water based Layer-by-Layer Surface Chemical Modification of Biomimetic Materials: Oil Repellency.  

UK PubMed Central (United Kingdom)

Biomimetic materials possessing hierarchical surface roughness thrive when complementary terminal chemical functionality is introduced. However, incorporating terminal functionality on the biomimetic material is the challenge; especially when its roughness needs to be preserved. Hence we report surface modification of biomimetic materials through water-based layer-by-layer deposition. The amine terminated biomimetic replica PDMS-replicaSilica/NH2 was prepared by treating silica modified replica (i.e. PDMS-replicaSilica) with the aqueous solution of branched ethoxylated polyethylenimine (EPEI). Next, -CF3 terminal PDMS-replicaSilica/NH2/Fluorocarbon was obtained by treating PDMS-replicaSilica/NH2 with the aqueous solution of phosphated fluorocarbon. PDMS-replicaSilica/NH2/Fluorocarbon showed superhydrophobicity (advancing ?water ~ 140?) and high oil repellency (advancing ?oil ~ 110?). X-ray photoelectron spectroscopy (XPS) revealed well-organized terminal -CF3 groups present on the PDMS-replicaSilica/NH2/Fluorocarbon surface. During the process of each chemical transformation, the complementary surface roughness present on the PDMS-replica was preserved and examined using Scanning Electron Microscopy. This method could be extended to get diverse terminal chemical functionality on the biomimetic materials which would furnish interesting surface properties in air or under water.

Ghosh N; Singh AV; Vaidya AA

2013-08-01

75

An innovative series of layered nanostructured aminoalkylsilica hybrid material  

International Nuclear Information System (INIS)

[en] An innovative series of silica-based hybrid materials containing pendant cationic ammoniumpropyl groups was obtained using the sol-gel method, by varying the molar ratio of the inorganic and organic precursors. Thermogravimetric analysis showed that samples were thermally stable up to 260 deg C. Results obtained by X-ray diffractometry, transmission electron microscopy, 29Si nuclear magnetic resonance and elemental analysis were compatible with a silsesquioxane layered structural model showing basal distances up to 5.4 nm, containing amorphous silica in the interlayer space. (author)

2009-01-01

76

First-Principle Description of Correlation Effects in Layered Materials  

CERN Document Server

We present a first-principle description of anisotropic materials characterized by having both weak (dispersion-like) and strong covalent bonds. We apply this scheme based on the Adiabatic--Connection Fluctuation--Dissipation Theorem (ACFDT) to hexagonal boron nitride. In-plane and out of plane bonding as well as vibrational dynamics are properly described both at equilibrium and when the layers are pulled apart. This formalism allows to ping-down the deficiencies of common exchange-correlation functionals and provides insight towards the inclusion of dispersion interaction into the correlation functional.

Marini, A; Rubio, A; Marini, Andrea; Rubio, Angel

2005-01-01

77

Development of under layer material for EUV lithography  

Science.gov (United States)

For the next generation lithography (NGL), several technologies have been proposed to achieve the 22nm-node devices and beyond. Extreme ultraviolet (EUV) lithography is one of the candidates for the next generation lithography. For lithography processes, the Line width roughness (LWR) and the pattern collapse of resist are the most critical issues for NGL, because of the small target critical dimension (CD) size and high aspect ratio. In this study, we design the new concept of EUV Under layer (UL) material to meet these requirements and study the impact of polymer design for pattern collapse behavior, pattern profile and LWR control by using EUV exposure tool.

Sakamoto, Rikimaru; Ho, Bang-Ching; Fujitani, Noriaki; Endo, Takafumi; Ohnishi, Ryuji

2011-03-01

78

Compound material thermal parameters for a layered material resembling an automobile firewall  

Energy Technology Data Exchange (ETDEWEB)

Heat transmission through a layered compound material consisting of carbon steel backing and insulation (either aluminized silver or fiberglass) was examined to determine thermal properties. The heat flux impinged on the insulation material side of this simulated ''firewall''. A heat transfer model was developed that could, in principle, be used to predict the heat transfer through layered compound materials using techniques of thermal property parameter estimation. The parameter estimates are based on thermocouple measurements of surface temperatures during heating on both sides of the material. The experiment analyzed in this article involved a vertical plate exposed on the insulation side to a transient step-applied radiant heat flux. The transient temperature measurements were fitted to heat transfer models. Thermal diffusivity and Biot number were estimated using ordinary least-squares nonlinear regression. (author)

McMasters, R.L.; Wichman, I.S.

2002-07-01

79

NAPHTHALENE DERIVATIVE, RESIST BOTTOM LAYER MATERIAL, AND PATTERNING PROCESS  

UK PubMed Central (United Kingdom)

PURPOSE: A naphthalene derivative, a manufacturing method, resist underlayer material, and resist underlayer formation method, and a pattern formation method are provided to improve etching-resistive characteristic, heat resistance, and solvent resistance. CONSTITUTION: A naphthalene derivative is represented by chemical formula 1 or 2. In the chemical formula 1, ring structured Ar1 and Ar2 respectively stand for benzene ring or naphthalene ring. n stands for arbitrary natural number which has polystyrene conversion average molecular weight of 100000 or less by gel permeation chromatography. In the chemical formula 2, the ring structured Ar1 and Ar2 stand for benzene ring or naphthalene ring. The resist lower layer film material uses the naphthalene derivative or a polymer which contains the naphthalene derivative as part of recurring unit.

KINSHO TAKESHI; KORI DAISUKE; TAKEMURA KATSUYA; WATANABE TAKERU; OGIHARA TSUTOMU

80

Hierarchically porous materials from layer-by-layer photopolymerization of high internal phase emulsions.  

Science.gov (United States)

A combination of high internal phase emulsion (HIPE) templating and additive manufacturing technology (AMT) is applied for creating hierarchical porosity within an acrylate and acrylate/thiol-based polymer network. The photopolymerizable formulation is optimized to produce emulsions with a volume fraction of droplet phase greater than 80 vol%. Kinetic stability of the emulsions is sufficient enough to withstand in-mold curing or computer-controlled layer-by-layer stereolithography without phase separation. By including macroscale cellular cavities within the build file, a level of controlled porosity is created simultaneous to the formation of the porous microstructure of the polyHIPE. The hybrid HIPE-AMT technique thus provides hierarchically porous materials with mechanical properties tailored by the addition of thiol chain transfer agent. PMID:23606606

Sušec, Maja; Ligon, Samuel Clark; Stampfl, Jürgen; Liska, Robert; Krajnc, Peter

2013-04-19

 
 
 
 
81

Materiales laminares pilareados: preparación y propiedades/ Pillared layered materials: preparation and properties  

Scientific Electronic Library Online (English)

Full Text Available Abstract in english The structure of several types of layered materials will be described. These include clays, layered double hydroxides, group IV metal phosphates and other layered materials. The preparation of the pillared materials and pillaring agents will be presented along with a description of the properties and applications of the products.

Pergher, Sibele B. C.; Corma, Avelino; Fornes, Vicente

1999-09-01

82

Materiales laminares pilareados: preparación y propiedades Pillared layered materials: preparation and properties  

Directory of Open Access Journals (Sweden)

Full Text Available The structure of several types of layered materials will be described. These include clays, layered double hydroxides, group IV metal phosphates and other layered materials. The preparation of the pillared materials and pillaring agents will be presented along with a description of the properties and applications of the products.

Sibele B. C. Pergher; Avelino Corma; Vicente Fornes

1999-01-01

83

Layer-by-layer polyelectrolyte deposition: a mechanism for forming biocomposite materials.  

Science.gov (United States)

Complex coacervates prepared from poly(aspartic acid) (polyAsp) and poly-l-histidine (polyHis) were investigated as models of the metastable protein phases used in the formation of biological structures such as squid beak. When mixed, polyHis and polyAsp form coacervates whereas poly-l-glutamic acid (polyGlu) forms precipitates with polyHis. Layer-by-layer (LbL) structures of polyHis-polyAsp on gold substrates were compared with those of precipitate-forming polyHis-polyGlu by monitoring with iSPR and QCM-D. PolyHis-polyAsp LbL was found to be stiffer than polyHis-polyGlu LbL with most water evicted from the structure but with sufficient interfacial water remaining for molecular rearrangement to occur. This thin layer is believed to be fluid and like preformed coacervate films, capable of spreading over both hydrophilic ethylene glycol as well as hydrophobic monolayers. These results suggest that coacervate-forming polyelectrolytes deserve consideration for potential LbL applications and point to LbL as an important process by which biological materials form. PMID:23600626

Tan, Yerpeng; Yildiz, Umit Hakan; Wei, Wei; Waite, J Herbert; Miserez, Ali

2013-05-03

84

Soda-anthraquinone lignin sacrificial agents in oil recovery  

Energy Technology Data Exchange (ETDEWEB)

A supplemental oil recovery method comprising injecting into a subterranean formation a fluid containing soda-anthraquinone lignin which is adsorbed by adsorptive sites therein and functions as a sacrificial agent and thereafter injecting a micellar dispersion containing a surfactant into the subterranean formation to displace the oil contained therein.

Dardis, R. E.

1985-04-09

85

Replica multichannel polymer chips with a network of sacrificial channels sealed by adhesive printing method.  

UK PubMed Central (United Kingdom)

Replica microchips for capillary array electrophoresis containing 10 separation channels (50 microm width, 50 microm depth and 100 microm pitch) and a network of sacrificial channels (100 microm width and 50 microm depth) were successfully fabricated on a poly(methyl methacrylate) (PMMA) substrate by injection molding. The strategy involved development of moving mask deep X-ray lithography to fabricate an array of channels with inclined channel sidewalls. A slight inclination of channel sidewalls, which can not be fabricated by conventional deep X-ray lithography, is highly required to ensure the release of replicated polymer chips from a mold. Moreover, the sealing of molded PMMA multichannel chips with a PMMA cover film was achieved by a novel bonding technique involving adhesive printing and a network of sacrificial channels. An adhesive printing process enables us to precisely control the thickness of an adhesive layer, and a network of sacrificial channels makes it possible to remove air bubbles and an excess adhesive, which are crucial to achieving perfect sealing of replica PMMA chips with well-defined channel and injection structures. A CCD camera equipped with an image intensifier was used to simultaneously monitor electrophoretic separations in ten micro-channels with laser-induced fluorescence detection. High-speed and high-throughput separations of a 100 bp DNA ladder and phi X174 Hae III DNA restriction fragments have been demonstrated using a 10-channel PMMA chip. The current work establishes the feasibility of mass production of PMMA multichannel chips at a cost-effective basis.

Dang F; Shinohara S; Tabata O; Yamaoka Y; Kurokawa M; Shinohara Y; Ishikawa M; Baba Y

2005-04-01

86

Enhanced electro-optic response of layered composite materials  

Science.gov (United States)

We have constructed a multilayered composite material consisting of alternating layers of rf-sputtered barium titanate and spin-coated polycarbonate containing a third-order nonlinear optical organic dopant. The effective nonlinear susceptibility of the composite describing the quadratic electro-optic effect was measured to have the value ?(3)=(3.2+0.2i)×10-21+/-25% (m/V)2. The real part of this value is a factor of 3.2+/-50% times larger than that of the doped polycarbonate, which is the dominant electro-optic component of the composite. We have modeled the experiment by using both effective medium theory and by solving the wave equation for our multilayered system, and we find that these approaches give consistent predictions which are in good agreement to the experimental results.

Nelson, Robert L.; Boyd, Robert W.

1999-04-01

87

Formation of nano-pyramids of layered materials with AFM  

UK PubMed Central (United Kingdom)

We have been able to raise squares of around 2 A in height of the layered materials Bi1.6Sb0.4Se3, Bi1.9Sb0.1Se3 and Bi2Se3 by means of contact atomic force microscopy in air. By raising squares on/beneath previously produced squares, Mayan-like pyramids have been constructed, each step of the pyramid being around 2 A in height. We neither remove matter from the surface nor produce a localized oxidation of the sample; we elevate a portion of it. When the surface is oxidized, the AFM cantilever pulls the oxide off producing holes. The raising of the squares is also possible in a nitrogen atmosphere.

Contera SA; Yoshinobu T; Iwasaki H; Bastl Z; Lostak P

2000-02-01

88

The functional layered organosilica materials prepared with anion surfactant templates.  

UK PubMed Central (United Kingdom)

A novel strategy for the synthesis of layered organosilica is demonstrated. The ionic interaction between the anionic group of a surfactant (sodium dodecyl sulfate) and the cationic organic group of an organosilane (3-aminopropyltrimethoxysilane, ATMS) under acidic conditions was utilized to create a layered organosilica at room temperature. The inorganic part of the organosilica layer was an Si-O hexagonal sheet, and organofunctional groups were alternately arranged on both sides of the sheet. The layered structure of the ATMS organosilica was retained after the removal of the surfactant with chloride anion. The properties of the layered ATMS organosilica were investigated. The layered ATMS-Cl organosilica is stable and possesses a definite layer structure in water or ethanol. Various kinds of anions can be intercalated in the interlayer space of the layered ATMS organosilicas and the layer was expanded dependent on the intercalated anions. The structure of the layered ATMS organosilica was well retained during the intercalation processes.

Yao K; Imai Y; Shi L; Dong A; Adachi Y; Nishikubo K; Abe E; Tateyama H

2005-05-01

89

The functional layered organosilica materials prepared with anion surfactant templates.  

Science.gov (United States)

A novel strategy for the synthesis of layered organosilica is demonstrated. The ionic interaction between the anionic group of a surfactant (sodium dodecyl sulfate) and the cationic organic group of an organosilane (3-aminopropyltrimethoxysilane, ATMS) under acidic conditions was utilized to create a layered organosilica at room temperature. The inorganic part of the organosilica layer was an Si-O hexagonal sheet, and organofunctional groups were alternately arranged on both sides of the sheet. The layered structure of the ATMS organosilica was retained after the removal of the surfactant with chloride anion. The properties of the layered ATMS organosilica were investigated. The layered ATMS-Cl organosilica is stable and possesses a definite layer structure in water or ethanol. Various kinds of anions can be intercalated in the interlayer space of the layered ATMS organosilicas and the layer was expanded dependent on the intercalated anions. The structure of the layered ATMS organosilica was well retained during the intercalation processes. PMID:15797421

Yao, Ken; Imai, Yusuke; Shi, LiYi; Dong, AiMei; Adachi, Yoshio; Nishikubo, Keiko; Abe, Eiichi; Tateyama, Hiroshi

2005-05-01

90

Sacrificial bonds and hidden length in biomaterials: A kinetic constitutive description of strength and toughness in bone.  

UK PubMed Central (United Kingdom)

Sacrificial bonds and hidden length in structural molecules account for the greatly increased fracture toughness of biological materials compared to synthetic materials without such structural features by providing a molecular-scale mechanism for energy dissipation. One example is in the polymeric glue connection between collagen fibrils in animal bone. In this paper we propose a simple kinetic model that describes the breakage of sacrificial bonds and the release of hidden length, based on Bell's theory. We postulate a master equation governing the rates of bond breakage and formation. This enables us to predict the mechanical behavior of a quasi-one-dimensional ensemble of polymers at different stretching rates. We find that both the rupture peak heights and maximum stretching distance increase with the stretching rate. In addition, our theory naturally permits the possibility of self-healing in such biological structures.

Lieou CK; Elbanna AE; Carlson JM

2013-07-01

91

Sacrificial bonds and hidden length in biomaterials: A kinetic constitutive description of strength and toughness in bone  

Science.gov (United States)

Sacrificial bonds and hidden length in structural molecules account for the greatly increased fracture toughness of biological materials compared to synthetic materials without such structural features by providing a molecular-scale mechanism for energy dissipation. One example is in the polymeric glue connection between collagen fibrils in animal bone. In this paper we propose a simple kinetic model that describes the breakage of sacrificial bonds and the release of hidden length, based on Bell's theory. We postulate a master equation governing the rates of bond breakage and formation. This enables us to predict the mechanical behavior of a quasi-one-dimensional ensemble of polymers at different stretching rates. We find that both the rupture peak heights and maximum stretching distance increase with the stretching rate. In addition, our theory naturally permits the possibility of self-healing in such biological structures.

Lieou, Charles K. C.; Elbanna, Ahmed E.; Carlson, Jean M.

2013-07-01

92

Sacrificial bonds and hidden length in biomaterials -- a kinetic, constitutive description of strength and toughness in bone  

CERN Multimedia

Sacrificial bonds and hidden length in structural molecules account for the greatly increased fracture toughness of biological materials compared to synthetic materials without such structural features, by providing a molecular-scale mechanism for energy dissipation. One example is in the polymeric glue connection between collagen fibrils in animal bone. In this paper, we propose a simple kinetic model that describes the breakage of sacrificial bonds and the release of hidden length, based on Bell's theory. We postulate a master equation governing the rates of bond breakage and formation. This enables us to predict the mechanical behavior of a quasi-one-dimensional ensemble of polymers at different stretching rates. We find that both the rupture peak heights and maximum stretching distance increase with the stretching rate. In addition, our theory naturally permits the possibility of self-healing in such biological structures.

Lieou, Charles K C; Carlson, Jean M

2013-01-01

93

An innovative series of layered nanostructured aminoalkylsilica hybrid material  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese Uma nova série de amostras de material híbrido à base de sílica, contendo o grupo catiônico amoniopropil ligado na forma pendente, foi obtida usando-se o método sol-gel de síntese, variando-se a razão molar entre o precursor inorgânico e o precursor orgânico. A análise termogravimétrica mostrou que as amostras são termicamente estáveis até 260 ºC. Os resultados obtidos por difratometria de raios X, microscopia eletrônica de transmissão, ressonância magn (more) ética nuclear de 29Si e análise elementar são compatíveis com o modelo estrutural de camadas de silsesquioxano com distâncias basais de até 5,4 nm, contendo sílica amorfa no espaço entre as camadas. Abstract in english An innovative series of silica-based hybrid materials containing pendant cationic ammoniumpropyl groups was obtained using the sol-gel method, by varying the molar ratio of the inorganic and organic precursors. Thermogravimetric analysis showed that samples were thermally stable up to 260 ºC. Results obtained by X-ray diffractometry, transmission electron microscopy, 29Si nuclear magnetic resonance and elemental analysis were compatible with a silsesquioxane layered stru (more) ctural model showing basal distances up to 5.4 nm, containing amorphous silica in the interlayer space.

Trindade, Carolina M. da; Stoll, Gabriela C.; Pereira, Altair S.; Costa, Tania M. H.; Benvenutti, Edilson V.

2009-01-01

94

Polyelectrolyte complex materials consisting of antibacterial and cell-supporting layers.  

Science.gov (United States)

The characterization of a polyelectrolyte complex material comprised of two biopolymers, a chitosan upper layer and a gellan gum under layer, is reported. It is shown that the upper layer of chitosan with incorporated levofloxacin displays an antibacterial activity, while the under layer of a gellan gum/TiO(2) composite supports the growth of fibroblastic cells. PMID:22223665

Mat Amin, Khairul Anuar; Gilmore, Kerry J; Matic, Jake; Poon, Stephen; Walker, Mark J; Wilson, Mark R; in het Panhuis, Marc

2011-12-30

95

Polyelectrolyte complex materials consisting of antibacterial and cell-supporting layers.  

UK PubMed Central (United Kingdom)

The characterization of a polyelectrolyte complex material comprised of two biopolymers, a chitosan upper layer and a gellan gum under layer, is reported. It is shown that the upper layer of chitosan with incorporated levofloxacin displays an antibacterial activity, while the under layer of a gellan gum/TiO(2) composite supports the growth of fibroblastic cells.

Mat Amin KA; Gilmore KJ; Matic J; Poon S; Walker MJ; Wilson MR; in het Panhuis M

2012-03-01

96

Process for forming one or more substantially pure layers in substrate material using ion implantation  

Energy Technology Data Exchange (ETDEWEB)

A process is disclosed for forming a substantially pure layer of an implantable element in a substrate material by (a) selecting an implantable element and a substrate material to be implanted which, at the temperatures to be used, have limited mutual solubility in one another and do not form any intermediate phases with one another; (b) implanting a sufficient amount of the implantable element in the substrate material to permit formation of the desired substantially pure layer of the implantable element in the substrate material; and (c) annealing the implanted substrate material to form the desired layer. The annealing step may not be required if the desired layer was formed during the implantation.

Musket, Ronald G. (San Ramon, CA); Brown, David W. (Livermore, CA); Munir, Zuhair A. (Davis, CA)

1990-01-01

97

Arhaeoastronomical analysis of Levinsadovka sacrificial complex (South Russia)  

CERN Multimedia

The article presents research data using arhaeoastronomical methods of Levinsadovka settlement sacrificial complex in Northern Black Sea coast. In this work, new method of accounting terrain elevations using topographic maps was developed in arhaeoastronomical studies. Calculations of azimuths of the sun and moon rise and set in the astronomically significant moments of the year were made and astronomical regularities in the organization of the sacrificial complex identified. Related to the moon directions, as the most dedicated, identified. Revealed that the stone tools and fragments, used as sacrifices, mark the direction to the northern minor standstill moonrise. A similar situation was found on two archaeological sites: in Bezymennoye II settlement South sanctuary and in Pustynka settlement religious building. Drawing on ethnographic and folklore data, it is concluded about semiotic connection of stone tools, found in these religious constructions, with the "thunderstones" and meteorites.

Vodolazhskaya, Larisa

2013-01-01

98

The determination of the cohesive force between layers in the multi layer materials using the laser adhesimeter  

Energy Technology Data Exchange (ETDEWEB)

The method of determination of the adhesion in multi layer materials using impulse lasers is elaborated. The laser adhesimeter (LA) allows to measure the adhesion in laboratory conditions and in a process of getting the material without interrupting a technological process.

Spesivtsev, B. [State Technological Univ. of Plant Polymers, St. Petersburg (Russian Federation)

1996-12-31

99

Plasma processes for formation of electronic structures with wide bandgap material layers  

International Nuclear Information System (INIS)

The plasma processes for formation of electronic structures with wide bandgap material layers have been presented in details. Especially plasma techniques for layers depositing and surface etching have been shown for preparation of layers of properties desirable for different microelectronic uses.

2001-01-01

100

Laminated metal composite formed from low flow stress layers and high flow stress layers using flow constraining elements and making same  

Energy Technology Data Exchange (ETDEWEB)

A laminated metal composite of low flow stress layers and high flow stress layers is described which is formed using flow constraining elements, preferably in the shape of rings, individually placed around each of the low flow stress layers while pressure is applied to the stack to bond the layers of the composite together, to thereby restrain the flow of the low flow stress layers from the stack during the bonding. The laminated metal composite of the invention is made by the steps of forming a stack of alternate layers of low flow stress layers and high flow stress layers with each layer of low flow stress material surrounded by an individual flow constraining element, such as a ring, and then applying pressure to the top and bottom surfaces of the resulting stack to bond the dissimilar layers together, for example, by compression rolling the stack. In a preferred embodiment, the individual flow constraining elements surrounding the layers of low flow stress material are formed of a material which may either be the same material as the material comprising the high flow stress layers, or have similar flow stress characteristics to the material comprising the high flow stress layers. Additional sacrificial layers may be added to the top and bottom of the stack to avoid damage to the stack during the bonding step; and these additional layers may then be removed after the bonding step. 5 figs.

Syn, C.K.; Lesuer, D.R.

1995-07-04

 
 
 
 
101

Laminated metal composite formed from low flow stress layers and high flow stress layers using flow constraining elements and making same  

Energy Technology Data Exchange (ETDEWEB)

A laminated metal composite of low flow stress layers and high flow stress layers is described which is formed using flow constraining elements, preferably in the shape of rings, individually placed around each of the low flow stress layers while pressure is applied to the stack to bond the layers of the composite together, to thereby restrain the flow of the low flow stress layers from the stack during the bonding. The laminated metal composite of the invention is made by the steps of forming a stack of alternate layers of low flow stress layers and high flow stress layers with each layer of low flow stress material surrounded by an individual flow constraining element, such as a ring, and then applying pressure to the top and bottom surfaces of the resulting stack to bond the dissimilar layers together, for example, by compression rolling the stack. In a preferred embodiment, the individual flow constraining elements surrounding the layers of low flow stress material are formed of a material which may either be the same material as the material comprising the high flow stress layers, or have similar flow stress characteristics to the material comprising the high flow stress layers. Additional sacrificial layers may be added to the top and bottom of the stack to avoid damage to the stack during the bonding step; and these additional layers may then be removed after the bonding step.

Syn, Chol K. (Moraga, CA); Lesuer, Donald R. (Livermore, CA)

1995-01-01

102

Fabrication of sacrificial anode cathodic protection through casting method  

International Nuclear Information System (INIS)

[en] Aluminum is one of the few metals that can be cast by all of the processes used in casting metals. These processes consist of die casting, permanent mold casting, sand casting (green sand and dry sand), plaster casting, investment casting, and continuous casting. Other processes such as lost foam, squeeze casting, and hot isostatic pressing are also used. Permanent mold casting method was selected in which used for fabricating of sacrificial anode cathodic protection. This product was ground for surface finished and fabricated in the cylindrical form and reinforced with carbon steel at a center of the anode. (Author)

2007-01-01

103

ZnO layers grown by Atomic Layer Deposition: A new material for transparent conductive oxide  

International Nuclear Information System (INIS)

[en] We demonstrate possibility of a control (by selection of zinc precursors and variation of a growth temperature) of electrical properties of ZnO films grown by Atomic Layer Deposition (ALD). ZnO films grown by ALD are used in test photovoltaic devices (solar cells) as transparent conductive oxides for upper, transparent layer in inorganic and organic solar cells, and as n-type partners of p-type CdTe.

2009-12-15

104

Standard test method for laboratory evaluation of magnesium sacrificial anode test specimens for underground applications  

CERN Document Server

1.1 This test method covers a laboratory procedure that measures the two fundamental performance properties of magnesium sacrificial anode test specimens operating in a saturated calcium sulfate, saturated magnesium hydroxide environment. The two fundamental properties are electrode (oxidation potential) and ampere hours (Ah) obtained per unit mass of specimen consumed. Magnesium anodes installed underground are usually surrounded by a backfill material that typically consists of 75 % gypsum (CaSO4·2H2O), 20 % bentonite clay, and 5 % sodium sulfate (Na2SO4). The calcium sulfate, magnesium hydroxide test electrolyte simulates the long term environment around an anode installed in the gypsum-bentonite-sodium sulfate backfill. 1.2 This test method is intended to be used for quality assurance by anode manufacturers or anode users. However, long term field performance properties may not be identical to property measurements obtained using this laboratory test. Note 1—Refer to Terminology G 15 for terms used ...

American Society for Testing and Materials. Philadelphia

1997-01-01

105

Interaction between a compliant material and an unstable boundary layer flow  

Energy Technology Data Exchange (ETDEWEB)

The response of a compliant coating to pressure fluctuations due to an unsteady boundary layer flow and the effect of the response on the stability of the flow field are examined. A pseudospectral solution of the Navier--Stokes equations is coupled to a finite element calculation of the behavior of the compliant material. In particular, the effect of material response on the growth rate of a Tollmien--Schlichting type instability in an unstable boundary layer is examined. Results are presented for three materials; a soft polyvinylchloride (PVC), a stiffer PVC, and a two-layer material consisting of a thick layer of soft PVC covered by a thin layer of neoprene. copyright 1988 Academic Press, Inc.

Hall, M.S.

1988-05-01

106

Interaction between a compliant material and an unstable boundary layer flow  

International Nuclear Information System (INIS)

The response of a compliant coating to pressure fluctuations due to an unsteady boundary layer flow and the effect of the response on the stability of the flow field are examined. A pseudospectral solution of the Navier--Stokes equations is coupled to a finite element calculation of the behavior of the compliant material. In particular, the effect of material response on the growth rate of a Tollmien--Schlichting type instability in an unstable boundary layer is examined. Results are presented for three materials; a soft polyvinylchloride (PVC), a stiffer PVC, and a two-layer material consisting of a thick layer of soft PVC covered by a thin layer of neoprene. copyright 1988 Academic Press, Inc.

1988-01-01

107

Zn's role in dissolution of al sacrificial anodes  

Science.gov (United States)

The role of alloying elements in the dissolution of aluminium sacrificial anodes was investigated. The effect of indium on the electrochemical performance of anode and the relationship between indium and impurities, such as silicon and iron, were studied. The distribution of indium in aluminium alloy was detected. The electrochemical behaviour of In-implanted aluminium alloy was also studied. The experimental results indicate that indium activates the surface of aluminium alloy and improves the electrochemical performance of alloy containing more amounts of impurity. Indium combines with silicon and iron. More satisfactory properties were obtained when the alloy's proportion of content of In to that of (Si+Fe) is about 1?(8˜10). The electrochemical properties of Al alloy, especially the surface activity of the anode were improved by ion implantation. Indium segregates in the alloy. The amount of Si and Fe in the In-rich segregated phase is richer than that in the matrix. It is proposed that the In-rich segregated phase particles activate the surface and promote the dissolution process of the aluminium sacrificial anode.

Sun, Hejian; Huo, Shizhong

1990-12-01

108

Method for forming a layer of synthetic corrosion products on tubing surfaces  

Energy Technology Data Exchange (ETDEWEB)

A method is provided for forming a synthetic corrosion product layer on tube surfaces. The method utilizes two dissimilar materials with different coefficients of thermal expansion. An object tube and sacrificial tube are positioned one inside the other such that an annular region is created between the two tubes' surfaces. A slurry of synthetic corrosion products is injected into this annular region and the assembly is heat treated. This heat causes the tubes to expand, the inner tube with the higher coefficient of expansion expanding more than the outer tube, thereby creating internal pressures which consolidate the corrosion products and adhere the corrosion products to the tubing surfaces. The sacrificial tube may then be removed by conventional chemical etching or mechanical methods.

Lane, Michael H. (Clifton Park, NY); Salamon, Eugene J. M. (Clifton Park, NY)

1996-01-01

109

Process for forming one or more substantially pure layers in substrate material using ion implantation  

International Nuclear Information System (INIS)

[en] A process is disclosed for forming a substantially pure layer of an implantable element in a substrate material by (a) selecting an implantable element and a substrate material to be implanted which, at the temperatures to be used, have limited mutual solubility in one another and do not form any intermediate phases with one another; (b) implanting a sufficient amount of the implantable element in the substrate material to permit formation of the desired substantially pure layer of the implantable element in the substrate material; and (c) annealing the implanted substrate material to form the desired layer. The annealing step may not be required if the desired layer was formed during the implantation. 2 figs

1989-08-10

110

Process for forming one or more substantially pure layers in substrate material using ion implantation  

Energy Technology Data Exchange (ETDEWEB)

A process is disclosed for forming a substantially pure layer of an implantable element in a substrate material by (a) selecting an implantable element and a substrate material to be implanted which, at the temperatures to be used, have limited mutual solubility in one another and do not form any intermediate phases with one another; (b) implanting a sufficient amount of the implantable element in the substrate material to permit formation of the desired substantially pure layer of the implantable element in the substrate material; and (c) annealing the implanted substrate material to form the desired layer. The annealing step may not be required if the desired layer was formed during the implantation. 2 figs.

Musket, R.G.; Brown, D.W.; Munir, Z.A.

1990-12-11

111

Process for forming one or more substantially pure layers in substrate material using ion implantation  

Energy Technology Data Exchange (ETDEWEB)

A process is disclosed for forming a substantially pure monocrystalline layer of an implantable element in a monocrystalline substrate material by (a) selecting an implantable element and a monocrystalline substrate material to be implanted which, at the temperatures to be used, have limited mutual solubility in one another and do not form any intermediate phases with one another; (b) implanting a sufficient amount of the implantable element in the substrate material to permit formation of the desired substantially pure layer of the implantable element in the substrate material; and (c) annealing the implanted substrate material to form the desired layer. The annealing step may not be required if the desired layer was formed during the implantation. Also disclosed is an article made by the process.

Musket, Ronald G. (San Ramon, CA); Brown, David W. (New Carrollton, MD); Munir, Zuhair A. (Davis, CA)

1992-01-01

112

Spinel/layered heterostructured cathode material for high-capacity and high-rate Li-ion batteries.  

UK PubMed Central (United Kingdom)

Best of both worlds: A heterostructured material is synthesized that comprises a core of layered lithium-rich material and an outer layer of nanospinel material. This spinel/layered heterostructured material maximizes the inherent advantages of the 3D Li(+) insertion/extraction framework of the spinel structure and the high Li(+) storage capacity of the layered structure. The material exhibits super-high reversible capacities, outstanding rate capability and excellent cycling ability.

Wu F; Li N; Su Y; Shou H; Bao L; Yang W; Zhang L; An R; Chen S

2013-07-01

113

Teo-iconología del poder sacrificial entre los mochica Teo-iconology of sacrificial power among the Moche  

Directory of Open Access Journals (Sweden)

Full Text Available Partiendo de las evidencias icónicas del rasgo predatorio y sus equivalentes narrativos presentes en diferentes piezas de la cultura mochica, el texto busca establecer (i) una metodología de aproximación al sacrificio caníbal que tenga en cuenta diversas formas icónicas de ‹escritura›, y (ii) una explicación so-ciocósmica de la política sacrificial. Al articular lo escritural y lo político, es posible aportar una nueva perspectiva a la rica discusión que sobre las relaciones entre canibalismo y poder han venido proponiendo los arqueólogos, los semióticos y los antropólogos de las culturas prehispánicas.Based on the iconographic evidences of predation and their narrative equivalents, present in different aspects of the Mochica culture, this essay seeks to establish (i) a methodology for approaching the cannibal sacrifice taking into account different forms of iconic ‹writing›; and (ii) establish a socio-cosmic explanation to sacrificial politics. By articulating these scriptural and political aspects, the paper will provide a new perspective to the rich discussion on the relationship between cannibalism and power that has been proposed by archaeologists, anthropologists and studies on the semiotic of Prehispanic cultures.

Adolfo Chaparro Amaya

2011-01-01

114

Teo-iconología del poder sacrificial entre los mochica/ Teo-iconology of sacrificial power among the Moche  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Partiendo de las evidencias icónicas del rasgo predatorio y sus equivalentes narrativos presentes en diferentes piezas de la cultura mochica, el texto busca establecer (i) una metodología de aproximación al sacrificio caníbal que tenga en cuenta diversas formas icónicas de ‹escritura›, y (ii) una explicación so-ciocósmica de la política sacrificial. Al articular lo escritural y lo político, es posible aportar una nueva perspectiva a la rica discusión (more) que sobre las relaciones entre canibalismo y poder han venido proponiendo los arqueólogos, los semióticos y los antropólogos de las culturas prehispánicas. Abstract in english Based on the iconographic evidences of predation and their narrative equivalents, present in different aspects of the Mochica culture, this essay seeks to establish (i) a methodology for approaching the cannibal sacrifice taking into account different forms of iconic ‹writing›; and (ii) establish a socio-cosmic explanation to sacrificial politics. By articulating these scriptural and political aspects, the paper will provide a new perspective to the rich discu (more) ssion on the relationship between cannibalism and power that has been proposed by archaeologists, anthropologists and studies on the semiotic of Prehispanic cultures.

Chaparro Amaya, Adolfo

2011-12-01

115

Defect Engineering of 2d Monatomic-Layer Materials  

Science.gov (United States)

Atomic-thick monolayer two-dimensional materials present advantageous properties compared to their bulk counterparts. The properties and behavior of these monolayers can be modified by introducing defects, namely defect engineering. In this paper, we review a group of common two-dimensional crystals, including graphene, graphyne, graphdiyne, graphn-yne, silicene, germanene, hexagonal boron nitride monolayers and MoS2 monolayers, focusing on the effect of the defect engineering on these two-dimensional monolayer materials. Defect engineering leads to the discovery of potentially exotic properties that make the field of two-dimensional crystals fertile for future investigations and emerging technological applications with precisely tailored properties.

Peng, Qing; Crean, Jared; Dearden, Albert K.; Huang, Chen; Wen, Xiaodong; Bordas, Stéphane P. A.; de, Suvranu

2013-09-01

116

Zinc-stearate-layered hydroxide nanohybrid material as a precursor to produce carbon nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: > In this work, a new organic-clay nanohybrid material, in which the organic moiety is intercalated between the inorganic layers, was synthesized using stearate anion as a guest and zinc hydroxide nitrate as an inorganic layered host by ion-exchange technique. Carbon nanoparticles were obtained by heat treating of the nanohybrid material, zinc-stearate-layered hydroxide. The proposed method is very simple, the chemicals used in the synthesis are cheap and the manner is economic and suitable for a large scale production of nano-sized carbon nanoparticles. - Abstract: Zinc-stearate-layered hydroxide nanohybrid was prepared using stearate anion as an organic guest, and zinc layered hydroxide nitrate, as a layered inorganic host by the ion-exchange method. Powder X-ray diffraction patterns and Fourier transform infrared results indicated that the stearate anion was actually intercalated into the interlayer of zinc layered hydroxide nitrate and confirmed the formation of the host-guest nanohybrid material. Also, surface properties data showed that the intercalation process has changed the porosity for the as-prepared nanohybrid material in comparison with that of the parent material, zinc hydroxide nitrate. The nanohybrid material was heat-treated at 600 deg. C under argon atmosphere. Stearate anion was chosen as a carbonaceous reservoir in the nanohybrid to produce carbon nanoparticles after heat-treating of the nanohybrid and subsequently acid washing process.

Ghotbi, Mohammad Yeganeh, E-mail: myeganeh@malayeru.ac.ir [Nanomaterials and Nanotechnology Program, Ceramic Engineering Department, Faculty of Engineering, University of Malayer, Malayer (Iran, Islamic Republic of); Materials and Energy Research Center, P.O. Box 14155-4777, Tehran (Iran, Islamic Republic of); Bagheri, Narjes [Materials and Energy Research Center, P.O. Box 14155-4777, Tehran (Iran, Islamic Republic of); Sadrnezhaad, S.K. [Materials and Energy Research Center, P.O. Box 14155-4777, Tehran (Iran, Islamic Republic of); Department of Materials Sciences and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Tehran (Iran, Islamic Republic of)

2011-02-03

117

Zinc-stearate-layered hydroxide nanohybrid material as a precursor to produce carbon nanoparticles  

International Nuclear Information System (INIS)

Research highlights: ? In this work, a new organic-clay nanohybrid material, in which the organic moiety is intercalated between the inorganic layers, was synthesized using stearate anion as a guest and zinc hydroxide nitrate as an inorganic layered host by ion-exchange technique. Carbon nanoparticles were obtained by heat treating of the nanohybrid material, zinc-stearate-layered hydroxide. The proposed method is very simple, the chemicals used in the synthesis are cheap and the manner is economic and suitable for a large scale production of nano-sized carbon nanoparticles. - Abstract: Zinc-stearate-layered hydroxide nanohybrid was prepared using stearate anion as an organic guest, and zinc layered hydroxide nitrate, as a layered inorganic host by the ion-exchange method. Powder X-ray diffraction patterns and Fourier transform infrared results indicated that the stearate anion was actually intercalated into the interlayer of zinc layered hydroxide nitrate and confirmed the formation of the host-guest nanohybrid material. Also, surface properties data showed that the intercalation process has changed the porosity for the as-prepared nanohybrid material in comparison with that of the parent material, zinc hydroxide nitrate. The nanohybrid material was heat-treated at 600 deg. C under argon atmosphere. Stearate anion was chosen as a carbonaceous reservoir in the nanohybrid to produce carbon nanoparticles after heat-treating of the nanohybrid and subsequently acid washing process.

1415-01-00

118

Selection of elastomeric materials for compliant-layered total hip arthroplasty.  

UK PubMed Central (United Kingdom)

A selection procedure has been developed to identify suitable commercial materials for use in compliant-layer artificial hip joints. Mechanical requirements, notably hardness and strength, as well as biocompatibility, constituted the specification for the compliant layer. Applying these constraints, candidate materials were identified in a broad range of polymeric material classes. Detailed sourcing and literature searching helped to identify materials appropriate to the application, with suitable mechanical and physical properties, as well as a history of successful clinical use. Some likely materials were identified but were prohibited from further consideration by limited commercial availability. Physical and mechanical characterization together with literature data were used to determine the relative ranking of the candidate materials and through a weighted materials property selection procedure the materials of choice were identified. The linear segmented aromatic polyurethanes, Tecothane 1085 and Estane 5714F1, emerged as the preferred materials.

Quigley FP; Buggy M; Birkinshaw C

2002-01-01

119

A "Layers of Negotiation" Model for Designing Constructivist Learning Materials.  

Science.gov (United States)

Discusses the process of designing a series of case-based interactive videodiscs to be used within a constructivist learning environment for elementary school science. Topics include assumptions about learners and learning; implications for learning materials; and implications for the instructional design process, including process-based versus…

Cennamo, Katherine S.; And Others

1996-01-01

120

Radionuclide separations using pillared layered materials. Final report  

International Nuclear Information System (INIS)

The objective of this project is to prepare an all inorganic strontium specific sorbent or ion exchanger for the removal of highly alkaline nuclear waste solutions. A series of clays and layered titanates were pillared and calcined to convert their essentially two dimensional structure to three dimensional porous structures with high surface areas. The pillaring agents were alumina, zirconia, chromia and silica based. The pillared clays, particularly those containing Zr pillars, achieved moderate (Kd as high at 13,700 ml/g with V:m = 28) selectivities for Sr2+. In contrast, the silica pillared titanates showed exceptional affinities for Sr2+ with Kd values in excess of 100,000 ml/g in 5M NaNO3 + 1M NaOH. These latter results suggest a more detailed study of the pillared titanates in the presence of simulants closely resembling real waste solutions

1995-01-01

 
 
 
 
121

Radionuclide separations using pillared layered materials. Final report  

Energy Technology Data Exchange (ETDEWEB)

The objective of this project is to prepare an all inorganic strontium specific sorbent or ion exchanger for the removal of highly alkaline nuclear waste solutions. A series of clays and layered titanates were pillared and calcined to convert their essentially two dimensional structure to three dimensional porous structures with high surface areas. The pillaring agents were alumina, zirconia, chromia and silica based. The pillared clays, particularly those containing Zr pillars, achieved moderate (Kd as high at 13,700 ml/g with V:m = 28) selectivities for Sr{sup 2+}. In contrast, the silica pillared titanates showed exceptional affinities for Sr{sup 2+} with Kd values in excess of 100,000 ml/g in 5M NaNO{sup 3} + 1M NaOH. These latter results suggest a more detailed study of the pillared titanates in the presence of simulants closely resembling real waste solutions.

Clearfield, A. [Texas A and M Univ., College Station, TX (United States). Research Foundation

1995-08-31

122

Advanced Materials and Detection Methods in Ultrathin-Layer Chromatography  

Science.gov (United States)

The performance of highly anisotropic, nanostructured, thin-film ultrathin-layer chromatography (UTLC) media with porosity and architecture engineered using the glancing-angle deposition (GLAD) process is investigated. Anisotropic structures resembling nanoblades are fabricated on the plates, producing channel-like features that partially decouple analyte migration from development direction, and offering new separation behaviours. These GLAD UTLC plates provide channel features that reduce transverse spot broadening while providing the wide pores required for rapid migration and high separation performance with plate numbers approaching 800. The rapid separations typical of these miniaturized plates call for new alternative detection techniques. I have designed, implemented and characterized a measurement system which records UTLC separations in full colour with 32 µm spatial resolution and 33 ms temporal resolution. My code analyzes multiple tracks per plate, filters analyte spots by colour, and automatically generates time-resolved figures of merit. Both absorption and transmission detection modes are examined, each of which offers their own advantages.

Oko, Anthony James

123

Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties  

Energy Technology Data Exchange (ETDEWEB)

One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O{sub 2}TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O{sub 2}TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

Kaeaeriaeinen, Tommi O., E-mail: tommi.kaariainen@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Cameron, David C., E-mail: david.cameron@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Lahtinen, Kimmo, E-mail: kimmo.lahtinen@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Johansson, Petri, E-mail: petri.johansson@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland)

2011-03-01

124

Preparation of plate-like mesoporous material from layered silicate RUB-15.  

UK PubMed Central (United Kingdom)

A plate-like mesoporous material was formed from the lamellar structure of layered silicate RUB-15. RUB-15 was synthesized by a hydrothermal method, as reported previously. TMA (tetramethylammonium) ions exist in the interlayer of RUB-15 were exchanged with C16 TMA (hexadecyl-trimethyl-ammonium) ions, and TEOS (tetraethylorthosilicate) was then intercalated in between the layers. After steaming, the obtained powder was calcined and characterized by XRD, N2 gas adsorption, and scanning electron microscopy (SEM). The XRD patterns and N2 adsorption-desorption isotherms of the finally obtained powders indicated the presence of mesopores in the sample. The morphology of powders was plate-like which originates from the structure of the starting material. Cross-sectional FE-SEM images of the final obtained powders revealed existence of mesopores between the layers. The morphology of the final obtained mesoporous materials was affected by their remaining layered structure due to the starting material RUB-15.

Kawai A; Ikeda T; Kodaira T; Endo A; Mizukami F

2013-04-01

125

Preparation of plate-like mesoporous material from layered silicate RUB-15.  

Science.gov (United States)

A plate-like mesoporous material was formed from the lamellar structure of layered silicate RUB-15. RUB-15 was synthesized by a hydrothermal method, as reported previously. TMA (tetramethylammonium) ions exist in the interlayer of RUB-15 were exchanged with C16 TMA (hexadecyl-trimethyl-ammonium) ions, and TEOS (tetraethylorthosilicate) was then intercalated in between the layers. After steaming, the obtained powder was calcined and characterized by XRD, N2 gas adsorption, and scanning electron microscopy (SEM). The XRD patterns and N2 adsorption-desorption isotherms of the finally obtained powders indicated the presence of mesopores in the sample. The morphology of powders was plate-like which originates from the structure of the starting material. Cross-sectional FE-SEM images of the final obtained powders revealed existence of mesopores between the layers. The morphology of the final obtained mesoporous materials was affected by their remaining layered structure due to the starting material RUB-15. PMID:23763172

Kawai, Akiko; Ikeda, Takuji; Kodaira, Tetsuya; Endo, Akira; Mizukami, Fujio

2013-04-01

126

Thermomechanical Response of Layered Materials. Final technical report  

Energy Technology Data Exchange (ETDEWEB)

A new experimental technique involving instrumented indentation was demonstrated for the specific purpose of calibrating certain variations in elastic properties as a function of position in thermally sprayed and sintered materials. This work experimentally demonstrated for the first time that controlled gradients in elastic properties alone can lead to the suppression of damage and cracking during contact loading. New methods were developed in this work for the estimation of mechanical properties of ductile alloys and brittle ceramics by recourse to continuous measurements of load-penetration curves with spherical microindenters.

Suresh, S.

2000-05-20

127

A new type of protective surface layer for high-capacity Ni-based cathode materials: nanoscaled surface pillaring layer.  

UK PubMed Central (United Kingdom)

A solid solution series of lithium nickel metal oxides, Li[Ni(1-x)M(x)]O2 (with M = Co, Mn, and Al) have been investigated intensively to enhance the inherent structural instability of LiNiO2. However, when a voltage range of Ni-based cathode materials was increased up to >4.5 V, phase transitions occurring above 4.3 V resulted in accelerated formation of the trigonal phase (P3m1) and NiO phases, leading to and pulverization of the cathode during cycling at 60 °C. In an attempt to overcome these problems, LiNi0.62Co0.14Mn0.24O2 cathode material with pillar layers in which Ni(2+) ions were resided in Li slabs near the surface having a thickness of ?10 nm was prepared using a polyvinylpyrrolidone (PVP) functionalized Mn precursor coating on Ni0.7Co0.15Mn0.15(OH)2. We confirmed the formation of a pillar layer via various analysis methods (XPS, HRTEM, and STEM). This material showed excellent structural stability due to a pillar layer, corresponding to 85% capacity retention between 3.0 and 4.5 V at 60 °C after 100 cycles. In addition, the amount of heat generation was decreased by 40%, compared to LiNi0.70Co0.15Mn0.15O2.

Cho Y; Oh P; Cho J

2013-03-01

128

Measurement and evaluation of the thermal diffusivity of two-layered materials  

Energy Technology Data Exchange (ETDEWEB)

Transient methods, such as those with pulse- or stepwise heating, have often been used to measure thermal diffusivity of various materials including layered composite materials. The aim of the present study is to investigate effects of various parameters on the measurement of thermal diffusivity when the transient methods are applied. Mainly a two-layered material in the pulsewise heating method is considered because of its simplicity and usefulness in identifying and determining the effects of the parameters. First, it has been shown that there exists a special condition for determining the thermal diffusivity of a component in the two-layered material whose other relevant thermophysical properties are known. Second, it has been shown that the thickness of the laser-beam absorption layer, which inevitably makes sample material into the two-layered material, may cause a relatively large error when the thermal diffusivity of the base material is high. Finally, it has been derived a definite relation between the apparent thermal diffusivity obtained from the temperature response and the mean thermal diffusivity, which has a physical meaning related to the thermal resistance. 4 refs., 8 figs., 2 tabs.

Araki, N.; Makino, A.; Mihara, J. (Shizuoka Univ., Hamamatsu (Japan))

1992-03-01

129

Effect of base layer materials on physiological and perceptual responses to exercise in personal protective equipment.  

UK PubMed Central (United Kingdom)

Ten men (non-firefighters) completed a 110 min walking/recovery protocol (three 20-min exercise bouts, with recovery periods of 10, 20, and 20 min following successive bouts) in a thermoneutral laboratory while wearing firefighting personal protective equipment over one of four base layers: cotton, modacrylic, wool, and phase change material. There were no significant differences in changes in heart rate, core temperature, rating of perceived exertion, thermal discomfort, and thermal strain among base layers. Sticking to skin, coolness/hotness, and clothing humidity sensation were more favorable (p < 0.05) for wool compared with cotton; no significant differences were identified for the other 7 clothing sensations assessed. Separate materials performance testing of the individual base layers and firefighting ensembles (base layer + turnout gear) indicated differences in thermal protective performance and total heat loss among the base layers and among ensembles; however, differences in heat dissipation did not correspond with physiological responses during exercise or recovery.

Smith DL; Arena L; Deblois JP; Haller JM; Hultquist EM; Lefferts WK; Russell T; Wu A; Fehling PC

2013-07-01

130

Identification of new pillared-layered carbon nitride materials at high pressure.  

UK PubMed Central (United Kingdom)

The compression of the layered carbon nitride C6N9H3 · HCl was studied experimentally and with density functional theory (DFT) methods. This material has a polytriazine imide structure with Cl(-) ions contained within C12N12 voids in the layers. The data indicate the onset of layer buckling accompanied by movement of the Cl(-) ions out of the planes beginning above 10-20 GPa followed by an abrupt change in the diffraction pattern and c axis spacing associated with formation of a new interlayer bonded phase. The transition pressure is calculated to be 47 GPa for the ideal structures. The new material has mixed sp(2)-sp(3) hybridization among the C and N atoms and it provides the first example of a pillared-layered carbon nitride material that combines the functional properties of the graphitic-like form with improved mechanical strength. Similar behavior is predicted to occur for Cl-free structures at lower pressures.

Salamat A; Deifallah M; Cabrera RQ; Corà F; McMillan PF

2013-01-01

131

Performance of Al-Zn-Sn alloy sacrificial anode in seawater  

International Nuclear Information System (INIS)

The paper describes the performance of Al-Zn-Sn alloy as a sacrificial anode for cathodic protection in seawater was investigated. Electrochemical technique used for measuring corrosion rate of the Al-Zn-Sn alloy sacrificial anode were Tafel plot. Potential measurement was also carried out using lab apparatus. All aspects of measurements such as corrosion potential, samples dimension and samples composition are presented in details. Experimental data and analysis results will be used in evaluating the performance of Al-Zn-Sn alloy sacrificial anode in seawater and will be discussed in this paper. (Author)

2006-01-01

132

Multi-layered poly-dimethylsiloxane as a non-hermetic packaging material for medical MEMS.  

UK PubMed Central (United Kingdom)

Poly-dimethylsiloxane (PDMS) is an attractive material for packaging implantable biomedical microdevices owing to its biocompatibility, ease in application, and bio-friendly mechanical properties. Unfortunately, devices encapsulated solely by PDMS lack the longevity for use in chronic implant applications due to defect-related moisture penetration through the packaging layer caused by conventional deposition processes such as spin coating. This paper describes an effort to improve the performance of PDMS as a packaging material by constructing the encapsulant from multiple, thin roller casted layers of PDMS as a part of a polymeric multi-material package.

Lachhman S; Zorman CA; Ko WH

2012-01-01

133

Multi-layered poly-dimethylsiloxane as a non-hermetic packaging material for medical MEMS.  

Science.gov (United States)

Poly-dimethylsiloxane (PDMS) is an attractive material for packaging implantable biomedical microdevices owing to its biocompatibility, ease in application, and bio-friendly mechanical properties. Unfortunately, devices encapsulated solely by PDMS lack the longevity for use in chronic implant applications due to defect-related moisture penetration through the packaging layer caused by conventional deposition processes such as spin coating. This paper describes an effort to improve the performance of PDMS as a packaging material by constructing the encapsulant from multiple, thin roller casted layers of PDMS as a part of a polymeric multi-material package. PMID:23366225

Lachhman, S; Zorman, C A; Ko, W H

2012-01-01

134

The correlation of layer waviness defect on compression strength of carbon fiber composite material  

International Nuclear Information System (INIS)

[en] As advanced composite materials having superior physical and mechanical properties are being developed, optimization of their production process is eagerly being sought. One of the most common defects in production of structural composites is layer waviness. Layer waviness is more pronounced in thick section flat and cylindrical laminates that are extensively used in missile casings. Submersibles and space platforms. Layer waviness undulates the entire layer of a multidirectional laminate in through-the-thickness direction leading to gross deterioration of its compression strength. This research investigates the influence of multiple layer waviness in a double nest formation on the compression strength of a composite laminate. Different wave fractions of wavy 0 degree layer were fabricated in IM/855 1- 7 carbon- epoxy composite laminate on a steel mold using single step fabrication procedure. The laminate was cured on a heated press according to specific curing cycle. Static compression testing was performed using short block compression fixture on an universal testing machine. The purpose of these tests was to determine the effects of multiple layer wave regions on the compression strength of composite laminate. The experimental and analytical results revealed that up to about 35% fraction of wavy 0 degree layers. The reduction in compression strength of composite laminate was constant after fraction of wavy 0 degree layers exceeded 35%. This analysis indicated that the percentage of 0 degree wavy layer may be used to estimate the reduction in compression strength of a composite laminate under restricted conditions. (author)

2005-01-01

135

Strength and thickness of the layer of materials used for ceramic veneers bonding.  

UK PubMed Central (United Kingdom)

The use of adhesive bonding systems and composites in prosthetic dentistry brought improved and more aesthetic prosthetic restorations. The adhesive bonding of porcelain veneers is based on the micromechanical and chemical bond between tooth surface, cement layer and ceramic material. The aim of the study was to measure the thickness of the material layer formed during cementing of a ceramic restoration, and - in the second part of the study - to test tension of these cements. The materials investigated comprised dual-curing materials: Variolink II, KoNroot Cem, KoNroot Cem Viscous and Panavia F 2.0, as well as a light-curing composite: Variolink Veneer. The thickness was measured with the use of ZIP Lite 250 optical gauging apparatus. SEM microscope - Hitachi Tabletop Microscope TM-100 - was used to analyse the characteristics of an adhesive bond and filler particle size of particular materials. Tension tests of the cements under study were carried out on the MTS Q Test 10 static electrodynamic apparatus. The tests showed that KoNroot Cem exhibited the best mechanical properties of bonding to enamel and dentin among the materials tested. Variolink II base light-curing cement formed the thinnest layer. All the materials tested formed the layer not exceeding 1/3 of ceramic restoration thickness.

Mazurek K; Mierzwi?ska-Nastalska E; Molak R; Ko?uchowski M; Pakie?a Z

2012-01-01

136

The influence of double nested layer waviness on compression strength of carbon fiber composite materials  

International Nuclear Information System (INIS)

[en] As advanced composite materials having superior physical and mechanical properties are being developed, optimization of their production processes in eagerly being sought. One of the most common defect in production of structural composites is layer waviness. Layer waviness is more pronounced in thick section flat and cylindrical laminates that are extensively used in missile casings, submersibles and space platforms. Layer waviness undulates the entire layers of a multidirectional laminate in through-the-thickness direction leading to gross deterioration of its compression strength. This research investigates the influence of multiple layer waviness in a double nest formation on the compression strength of a composite laminate. Different wave fractions of wave 0 degree centigrade layer fabricated in IM/85510-7 carbon - epoxy composite laminate on a steel mold using single step fabrication procedure. The laminate was cured on a heated press according to specific curing cycle. Static compression testing was performed using NASA short block compression fixture on an MTS servo Hydraulic machine. The purpose of these tests was to determine the effects of multiple layer wave regions on the compression strength of composite laminate. The experimental and analytical results revealed that up to about 35% fraction of wave 0 degree layer exceeded 35%. This analysis indicated that the percentage of 0 degree wavy layer may be used to estimate the reduction in compression strength of a composite laminate under restricted conditions. (author)

1997-01-01

137

Direct grafting of anti-fouling polyglycerol layers to steel and other technically relevant materials.  

UK PubMed Central (United Kingdom)

Direct grafting of hyperbranched polyglycerol (PG) layers onto the oxide surfaces of steel, aluminum, and silicon has been achieved through surface-initiated polymerization of 2-hydroxymethyloxirane (glycidol). Optimization of the deposition conditions led to a protocol that employed N-methyl-2-pyrrolidone (NMP) as the solvent and temperatures of 100 and 140°C, depending on the substrate material. In all cases, a linear growth of the PG layers could be attained, which allows for control of film thickness by altering the reaction time. At layer thicknesses >5nm, the PG layers completely suppressed the adhesion of albumin, fibrinogen, and globulin. These layers were also at least 90% bio-repulsive for two bacteria strains, E. coli and Acinetobacter baylyi, with further improvement being observed when the PG film thickness was increased to 17nm (up to 99.9% bio-repulsivity on silicon).

Weber T; Bechthold M; Winkler T; Dauselt J; Terfort A

2013-06-01

138

Spatial quadratic solitons guided by narrow layers of a nonlinear material  

CERN Document Server

We report analytical solutions for spatial solitons supported by layers of a quadratically nonlinear material embedded into a linear planar waveguide. A full set of symmetric, asymmetric, and antisymmetric modes pinned to a symmetric pair of the nonlinear layers is obtained. The solutions describe a bifurcation of the subcritical type, which accounts for the transition from the symmetric to asymmetric modes. The antisymmetric states (which do not undergo the bifurcation) are completely stable (the stability of the solitons pinned to the embedded layers is tested by means of numerical simulations). Exact solutions are also found for nonlinear layers embedded into a nonlinear waveguide, including the case when the uniform and localized nonlinearities have opposite signs (competing nonlinearities). For the layers embedded into the nonlinear medium, stability properties are explained by comparison to the respective cascading limit.

Shapira, Asia; Malomed, Boris A; Arie, Ady

2011-01-01

139

Crack propagation in the vicinity of the interface in layered materials  

Directory of Open Access Journals (Sweden)

Full Text Available The paper deals with the problem of crack propagation in the vicinity of the interface in layered materials. Layered materials are often used in practice, primarily because of their better mechanical properties in comparison with the properties of individual materials components. The configuration of a crack with its tip at the bi-material interface can be created during crack propagation in the structure. It is important to decide if the crack propagates into the second material in this case. The step change of material properties at the bi-material interface means that classical linear elastic fracture mechanics are not appropriate. A generalized approach has to be applied. In this paper, two criteria are applied for the determination of the critical value of an applied load. Knowledge of these values is important for the estimation of the service life time of such structures. The results obtained can be used especially for multi-layer polymer composites designs. On the basis of the procedures presented, suitable materials combinations can be suggested for new composite structures.

Šestáková L.; Náhlík L.; Huta? P.; Knésl Z.

2009-01-01

140

Synthesis of porous CrO{sub x} pillared octahedral layered manganese oxide materials  

Energy Technology Data Exchange (ETDEWEB)

Chromium oxide pillared manganese oxide materials were prepared by intercalating layered manganese oxide with chromium hydroxyl acetate clusters under reflux condition. The as-synthesized materials were heated at 200 C in flowing nitrogen for 1 h to result in chromium oxide pillared manganese oxides. X-ray diffraction, UV-vis, FTIR, BET surface area and pore size distribution, temperature programmed desorption, elemental analysis, and X-ray absorption spectrometry were used to study the intercalating process and the structures of the pillared materials. Porous materials with a high specific surface area and a narrow pore size distribution (18 {angstrom}) were obtained. The removal of bound water and dehydroxylated water was responsible for the production of high surface area in the pillared material. The decomposition of acetate groups bidentate-linked to Cr starting at 200 C in N{sub 2} resulted in a concomitant decrease in porosity. Although the ordering of the layers was largely destroyed and the materials remained amorphous under XRD study, TEM morphology studies suggest that the material was still layered EXAFS studies indicate the formation of Cr-O-Mn bonds in the resultant materials via corner-shared linkages of CrO{sub 6} and MnO{sub 6} octahedra.

Ma, Y.; Suib, S.L.; Ressler, T.; Wong, J.; Lovallo, M.; Tsapatsis, M.

1999-12-01

 
 
 
 
141

Two-dimensional nanosheets produced by liquid exfoliation of layered materials.  

UK PubMed Central (United Kingdom)

If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties.

Coleman JN; Lotya M; O'Neill A; Bergin SD; King PJ; Khan U; Young K; Gaucher A; De S; Smith RJ; Shvets IV; Arora SK; Stanton G; Kim HY; Lee K; Kim GT; Duesberg GS; Hallam T; Boland JJ; Wang JJ; Donegan JF; Grunlan JC; Moriarty G; Shmeliov A; Nicholls RJ; Perkins JM; Grieveson EM; Theuwissen K; McComb DW; Nellist PD; Nicolosi V

2011-02-01

142

Two-dimensional nanosheets produced by liquid exfoliation of layered materials.  

Science.gov (United States)

If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties. PMID:21292974

Coleman, Jonathan N; Lotya, Mustafa; O'Neill, Arlene; Bergin, Shane D; King, Paul J; Khan, Umar; Young, Karen; Gaucher, Alexandre; De, Sukanta; Smith, Ronan J; Shvets, Igor V; Arora, Sunil K; Stanton, George; Kim, Hye-Young; Lee, Kangho; Kim, Gyu Tae; Duesberg, Georg S; Hallam, Toby; Boland, John J; Wang, Jing Jing; Donegan, John F; Grunlan, Jaime C; Moriarty, Gregory; Shmeliov, Aleksey; Nicholls, Rebecca J; Perkins, James M; Grieveson, Eleanor M; Theuwissen, Koenraad; McComb, David W; Nellist, Peter D; Nicolosi, Valeria

2011-02-01

143

Contraction stress of flowable composite materials and their efficacy as stress-relieving layers.  

UK PubMed Central (United Kingdom)

BACKGROUND: The authors compared the polymerization contraction stress produced by flowable resin-based composites with stress values produced by nonflowable composites. They also measured the stress reduction produced by placing a precured layer of flowable composite under a nonflowable composite. METHODS: The authors first tested four flowable and six nonflowable composite materials for contraction stress in a tensiometer. In the second part of the study, they applied a 1.4-millimeter-thick layer of flowable composite or unfilled resin and precured it in the test apparatus to assess the stress relief produced by a low-modulus material during light curing of a subsequent layer of highly filled composite. Flexural moduli of the precured materials were determined via a three-point bending test. RESULTS: The stress values ranged between 6.04 and 9.10 megapascals. The authors found no significant differences in stress between flowable and nonflowable composites. Microfilled composites produced lower contraction stress than did hybrids. The flexural modulus of the flowable composites varied between 4.1 and 8.2 GPa. Regarding the effect of a precured layer of composite on contraction stress, the authors observed significant reductions with only one of the flowable materials and with the unfilled resin. CONCLUSIONS: The flowable composites produced stress levels similar to those of nonflowable materials. Most of the flowable materials tested did not produce significant stress reductions when used under a nonflowable composite. CLINICAL IMPLICATIONS: Using a flowable resin-based composite as a restorative material is not likely to reduce the effects of polymerization stress. When used in a thin layer under a nonflowable composite, the stress reduction depended on the elastic modulus of the lining material.

Braga RR; Hilton TJ; Ferracane JL

2003-06-01

144

Superior hybrid cathode material containing lithium-excess layered material and graphene for lithium-ion batteries.  

UK PubMed Central (United Kingdom)

Graphene-wrapped lithium-excess layered hybrid materials (Li(2)MnO(3)·LiMO(2), M = Mn, Ni, Co, hereafter abbreviated as LMNCO) have been synthesized and investigated as cathode materials for lithium-ion batteries. Cyclic voltammetry measurement shows a significant reduction of the reaction overpotential in benefit of the graphene conducting framework. The electrochemical impedance spectroscopy results reveal that the graphene can greatly reduce the cell resistance, especially the charge transfer resistance. Our investigation demonstrates that the graphene conducting framework can efficiently alleviate the polarization of pristine LMNCO material leading to an outstanding enhancement in cell performance and cycling stability. The superior electrochemical properties support the fine hybrid structure design by enwrapping active materials in graphene nanosheets for high-capacity and high-rate cathode materials.

Jiang KC; Wu XL; Yin YX; Lee JS; Kim J; Guo YG

2012-09-01

145

Process for forming one or more substantially pure layers in substrate material using ion implantation  

Energy Technology Data Exchange (ETDEWEB)

The method comprises selecting an implantable element and a substrate material to be implanted which, at the implant/anneal temperatures, have limited mutual solubility and have no intermediate phases formed. In an example, Be is implanted with 11 {times}10{sup 17} Al/cm{sup 2} at 200 keV and then annealed for 1 h at 500 C. Rutherford backscattering shows that layer formation occurred during the anneal. SEM shows rectangular Be defects in the Al layer. Other examples of implantable elements and suitable substrate materials are tabulated. 6 figs, 1 table. (DLC)

Musket, R.G.; Brown, D.W.; Munir, Z.A.

1990-12-31

146

Investigation of the influence of laser radiation on material properties of transparent conductive layers  

Science.gov (United States)

Organic electronic devices like organic thin film transistors with micron or even sub-micron sized features can be fabricated at high throughput by fast printing methods combined with high resolution laser patterning. In addition, such an approach is of interest for applications with lower requirements in resolution, such as OLEDs or OPV. Due to its high flexibility and adaptability to almost any material or material system, laser processing is a perfect tool for the production of organic electronics. In all the applications above, it is of severe importance not to cause damage to adjacent material or layers by laser radiation. For transparent conductive layers laser-induced damage can lead to changes in conductivity, transparency or material composition (e.g. oxidation). Therefore, a comprehensive study was performed to investigate the influence of laser radiation below ablation threshold on material properties of transparent conducting layers (e.g. ITO, PEDOT/PSS). Samples were irradiated by a large range of wavelengths, reaching from the deep UV (193 nm) up to near IR (1064 nm). To identify changes in material properties the samples were characterized by microscopic methods like high resolution laser scanning microscopy and conductive atomic force microscopy. Also spectroscopic methods like UV/VIS/NIR absorption spectroscopy as well as X-ray photoelectron spectroscopy were used in order to determine changes in conductivity and material composition.

Schaefer, Moritz; Esser, Alexander; Schulz-Ruhtenberg, Malte; Holtkamp, Jens; Gillner, Arnold

2012-09-01

147

Elastic properties of a material composed of alternating layers of negative and positive Poisson's ratio  

International Nuclear Information System (INIS)

The theory of elasticity predicts a variety of phenomena associated with solids that possess a negative Poisson's ratio. The fabrication of metamaterials with a 'designed' microstructure that exhibit a Poisson's ratio approaching the thermodynamic limits of 1/2 and -1 increases the likelihood of realising these phenomena for applications. In this work, we investigate the properties of a layered composite, with alternating layers of materials with negative and positive Poisson's ratio approaching the thermodynamic limits. Using the finite element method to simulate uniaxial loading and indentation of a free standing composite, we observed an increase in the resistance to mechanical deformation above the average value of the two materials. Even though the greatest increase in stiffness is gained as the thermodynamic limits are approached, a significant amount of added stiffness can be attained, provided that the Young's modulus of the negative Poisson's ratio material is not less than that of the positive Poisson's ratio material.

2009-04-15

148

Formation of a screening layer under irradiation of solid materials by power plasma flows  

International Nuclear Information System (INIS)

The dynamics of the target plasma, formed by irradiation of solid-state materials by high-temperature currents of hydrogen plasma with the power density of W ? 10 MW/cm2, is experimentally studied. Interaction of the plasma with the materials proceeded in the magnetic field, oriented perpendicular to the surface. Graphite, plexiglas, quartz, boron nitride, aluminium, stainless steel, copper, molybdenum, tungsten were used as the target material. It is shown that a dense layer (n > 1017 cm-3) of the target plasma, screening the surface from the direct impact of the plasma current, is formed during t = 1-2 ?s on the irradiated surface. The magnetic field limits the target plasma expansion across the power lines and establishes unidimensional hydrodynamical behavior of the plasma. The dynamics and parameters of the screening layer plasma essentially depend on the target materials

1999-01-01

149

Simulation of trapping properties of high ? material as the charge storage layer for flash memory application  

International Nuclear Information System (INIS)

We investigated the trapping properties of high ? material as the charge storage layer in non-volatile flash memory devices using a two-dimensional device simulator, Medici. The high ? material is sandwiched between two silicon oxide layers, resulting in the Silicon-Oxide-High ?-Oxide-Silicon (SOHOS) structure. The trap energy levels of the bulk electron traps in high ? material were determined. The programming and erasing voltage and time using Fowler Nordheim tunneling were estimated by simulation. The effect of deep level traps on erasing was investigated. Also, the effect of bulk traps density, thickness of block oxide and thickness of high ? material on the threshold voltage of the device was simulated.

1175-01-00

150

High temperature materials synthesis without heat: Oxide layer growth on electronic materials using high-kinetic-energy atomic oxygen  

Energy Technology Data Exchange (ETDEWEB)

This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The authors examined thin-film materials-synthesis processes in which chemical reactions are initiated using high-kinetic-energy neutral atomic species instead of high temperatures. The research is aimed at producing device-quality insulating oxide layers on semiconductor materials. Thick, uniform, and fully oxidized insulating layers of unprecedented quality are formed on gallium arsenide by exposure of wafer substrates to a high kinetic-energy ({approximately}3eV) neutral atomic-oxygen beam. The nonthermal oxidation process does not disrupt the crystalline order of the substrate and no detectable elemental arsenic is produced at the oxide/gallium arsenide interface.

Hoffbauer, M.A.; Cross, J.B.; Archuleta, F.A.

1996-04-01

151

Steady State Crack Propagation in Layered Material Systems Displaying Visco-plastic Behaviour  

DEFF Research Database (Denmark)

The steady state fracture toughness of elastic visco-plastic materials is studied numerically, using both a conventional and a higher order model. Focus is on the combined effect of strain hardening, strain gradient hardening and strain rate hardening on cracking in layered material systems, and predictions for the crack tip shielding ratio is brought forward. Included is a novel procedure for extracting information on the rate-independent toughness without approaching this numerically cumbersome limit.

Nielsen, Kim Lau

2012-01-01

152

The collective mechanism of mass transport in surface layers of irradiated materials  

International Nuclear Information System (INIS)

The new collective mechanism of mass transport connected with diffusion of submicroscopic dislocation loops (SDL) which can act in surface layers of radiated crystalline materials is proposed and substantiated. It is shown that in real conditions SDL can diffuse essentially faster then point defects

2001-01-01

153

Uncovering Magnetic Order in Nanostructured Disordered Materials : A Study of Amorphous Magnetic Layered Structures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The scope of this thesis is the study of the interplay between structure and magnetism in amorphous materials. The investigations focus on the growth of amorphous layers and the study of the in?uence of structural disorder and reduced physical extension on the magnetic properties of thin ?lms and mu...

Korelis, Panagiotis

154

Electrohydrodynamic pulsatile flow in a channel bounded by porous layer of smart material  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Electrohydrodynamic dispersion due to pulsatile flow in a channel bounded by porous layer of smart material is studied considering both steady and unsteady cases using both BJ and BJR-slip conditions. We found that in the case of steady flow, the dispersion coefficient, Ds * decreases with an increa...

Ng, CO; Rudraiah, N; Nagaraj, C

155

Treatment method of magnesium alloy material capable of being absorbed by human body and magnesium alloy composite layer  

UK PubMed Central (United Kingdom)

The invention provides a treatment method of a magnesium alloy material capable of being absorbed by a human body and a magnesium alloy composite layer. The treatment method comprises the following steps: (1) the magnesium alloy material capable of being absorbed by the human body is washed to remove surface pollutants (2) the magnesium alloy material capable of being absorbed by the human body is put in electrolyte solution containing silicon, micro-arc oxidation treatment is carried out under the condition that the voltage is larger than 200 to 600V, so as to lead the surface of the magnesium alloy material capable of being absorbed by living creature to form a micro-arc oxidation film layer and (3) the magnesium alloy material capable of being absorbed by the human body after micro-arc oxidation treatment is washed and then dried. The magnesium alloy composite layer comprises the magnesium alloy material capable of being absorbed by the human body as matrix and the micro-arc oxidation film layer which covers the surface of the matrix and has the thickness of 0.5 to 50 microns the micro-arc oxidation film layer comprises an inner layer and an outer layer, wherein the inner layer is an magnesium oxide layer and the outer layer is a crystalline compound layer of magnesium silicate or/and magnesium metasilicate. The magnesium alloy composite layer achieves the purpose of prolonging the degradation time of magnesium alloy.

DEYUAN ZHANG; YILONG CHEN

156

Crystallographic dependence of the lateral undercut wet etch rate of Al0.5In0.5P in diluted HCl for III-V sacrificial release  

DEFF Research Database (Denmark)

The authors investigated the use of InAlP as a sacrificial layer lattice-matched to GaAs when diluted hydrochloric acid is used for sacrificial etching. They show that InAlP can be used to fabricate submicrometer air gaps in micro-opto-electro-mechanical systems and that a selectivity toward GaAs larger than 500 is achieved. This selectivity enables fabrication control of the nanometer-size structures required in photonic crystal and high-index contrast subwavelength grating structures. The crystallographic dependence of the lateral etch rate in InAlP is shown to be symmetric around the ?110? directions where an etch rate of 0.5??m/min is obtained at 22?°C in HCl:2H2O. Since the etch rate in the ?100? directions exceeds by ten times that of the ?110? directions, InAlP may be used in sacrificial release of high-aspect ratio structures. Free-hanging structures with length to air-gap aspect ratios above 600 are demonstrated by use of critical point drying following the sacrificial etch.

Ansbæk, Thor; Semenova, Elizaveta

2013-01-01

157

Comparison of some coating techniques to fabricate barrier layers on packaging materials  

International Nuclear Information System (INIS)

Atomic layer deposition (ALD), electron beam evaporation, magnetron sputtering and a sol-gel method were used to deposit thin aluminum oxide coatings onto two different fiber-based packaging materials of commercial board grades coated with synthetic and biodegradable polymers. Significant decreases in both the water vapor and oxygen permeation rates were observed. With each technique the barrier performance was improved. However, among the techniques tested ALD was found to be most suitable. Our results moreover revealed that biodegradable polylactic acid-coated paperboard with a 25-nm thick layer of aluminum oxide grown by ALD on top of it showed promising barrier characteristics against water vapor and oxygen.

1000-01-00

158

Spin-transfer phenomena in layered magnetic structures: Physical phenomena and materials aspects  

International Nuclear Information System (INIS)

During the past 20 years, layered structures consisting of ferromagnetic layers and spacers of various material classes with a thickness of only a few nanometers have revealed a variety of exciting and potentially very useful phenomena not present in bulk material. Representing distinct manifestations of spin-transfer processes, these phenomena may be categorized into interlayer exchange coupling (IEC), giant magnetoresistance (GMR), tunneling magnetoresistance (TMR), and the more recently discovered spin-transfer torque effect leading to current-induced magnetization switching (CIMS) and current-driven magnetization dynamics. These phenomena clearly confer novel material properties on magnetic layered structures with respect to the (magneto-)transport and the magnetostatic as well as magnetodynamic behavior. Here, we will first concentrate on the less well understood aspects of IEC across insulating and semiconducting interlayers and relate the observations to TMR in the corresponding structures. In this context, we will also discuss more recent advances in TMR due to the use of electrodes made from Heusler alloys and the realization of coherent tunneling in epitaxial magnetic tunneling junctions. Finally, we will review our results on CIMS in epitaxial magnetic nanostructures showing that normal and inverse CIMS can occur simultaneously in a single nanopillar device. In all cases discussed, material issues play a major role in the detailed understanding of the spin-transfer effects, in particular in those systems that yield the largest effects and are thus of utmost interest for applications.

2007-01-01

159

Formation of nanocrystalline surface layers in various metallic materials by near surface severe plastic deformation  

Directory of Open Access Journals (Sweden)

Full Text Available The surface of the various kinds of metallic materials sheets were severely deformed by wire-brushing at ambient temperature to achieve nanocrystalline surface layer. The surface layers of the metallic materials developed by the near surface severe plastic deformation (NS-SPD) were characterized by means of TEM. Nearly equiaxed nanocrystals with grain sizes ranging from 30 to 200 nm were observed in the near surface regions of all the severely scratched metallic materials, which are Ti-added ultra-low carbon interstitial free steel, austenitic stainless steel (SUS304), 99.99 wt.%Al, commercial purity aluminum (A1050 and A1100), Al–Mg alloy (A5083), Al-4 wt.%Cu alloy, OFHC-Cu (C1020), Cu–Zn alloy (C2600) and Pb-1.5%Sn alloy. In case of the 1050-H24 aluminum, the depth of the surface nanocrystalline layer was about 15 ?m. It was clarified that wire-brushing is an effective way of NS-SPD, and surface nanocrystallization can be easily achieved in most of metallic materials.

Masahide Sato, Nobuhiro Tsuji, Yoritoshi Minamino and Yuichiro Koizumi

2004-01-01

160

The Influnece of Peat Layer on Hidrogen and Aluminium Concentration Originating from the Substratum Sulphidic Materials  

Directory of Open Access Journals (Sweden)

Full Text Available Much of peatland in Indonesia has sulphidic materials as substratum. Soil acidity and metal elements in peatland may originate from the sulphidic materials which occur underneath of the peat layer. Peat soil buffering capacity and chelating ability of the peat materials regulate the soil acidity and metal solubility in the peatland. The study was aimed to examine the influence of peat thickness and land hydrological conditions on the concentrations of exchangeable aluminium (Al) and hidrogen (H) in the peatland. The study was carried out on peaty acid sulphate soil, deep peat, moderate peat and shallow peat. Exchangeable Al and H were observed in the wet season, transition from wet to dry season and dry season. The results showed that exchangeables of Al and H were mainly originated from sulphidic material which were occured underneath of the peat layer. Peat layer had an important role on the solubility of Al and H in the peatland. Peat thickness had influence on exchangeable-Al and H, 50 cm of the peat thickness (shallow peat) was the critical for peat function to reduce the Al and H solubility in the peatland. Hydrological condition factor did not influence on the solubility of Al and H.

Arifin Fahmi; Bostang Radjagukguk; Benito Heru Purwanto; Eko Hanudin

2012-01-01

 
 
 
 
161

Frequency characterization of thin soft magnetic material layers used in spiral inductors  

International Nuclear Information System (INIS)

[en] The paper details the characterization of thin magnetic materials layers, particularly soft materials, with respect to their behaviour in frequency (from 10 MHz to 1 GHz). The proposed method is suitable for any soft but insulating magnetic material; Yttrium Iron Garnet (YIG) is used as an example. The principle is based on a comparison between simulations for different values of the permeability and measurement values versus frequency of planar inductor structures; an experimental validation is proposed as well. Thin magnetic material is first deposited on an alumina substrate using RF sputtering technique; a planar spiral winding of copper is then deposited on the magnetic material by the same technique. The effective permeability versus frequency is obtained by comparing two samples of spiral windings with and without magnetic material. Network analyser measurements on samples of various geometrical dimensions and of different thicknesses are necessary to determine the effective magnetic permeability; we have obtained a relative effective permeability of about 30 for seven turns spiral inductor of a 17 ?m YIG film. - Highlights: ? A simple and original method is presented for the characterization of soft magnetic layer. ? This is a non-destructive method based on standard equipment. ? The principle is based on a comparison between simulations and measurement. ? An experimental validation is proposed as well.

2012-01-01

162

Frequency characterization of thin soft magnetic material layers used in spiral inductors  

Energy Technology Data Exchange (ETDEWEB)

The paper details the characterization of thin magnetic materials layers, particularly soft materials, with respect to their behaviour in frequency (from 10 MHz to 1 GHz). The proposed method is suitable for any soft but insulating magnetic material; Yttrium Iron Garnet (YIG) is used as an example. The principle is based on a comparison between simulations for different values of the permeability and measurement values versus frequency of planar inductor structures; an experimental validation is proposed as well. Thin magnetic material is first deposited on an alumina substrate using RF sputtering technique; a planar spiral winding of copper is then deposited on the magnetic material by the same technique. The effective permeability versus frequency is obtained by comparing two samples of spiral windings with and without magnetic material. Network analyser measurements on samples of various geometrical dimensions and of different thicknesses are necessary to determine the effective magnetic permeability; we have obtained a relative effective permeability of about 30 for seven turns spiral inductor of a 17 {mu}m YIG film. - Highlights: Black-Right-Pointing-Pointer A simple and original method is presented for the characterization of soft magnetic layer. Black-Right-Pointing-Pointer This is a non-destructive method based on standard equipment. Black-Right-Pointing-Pointer The principle is based on a comparison between simulations and measurement. Black-Right-Pointing-Pointer An experimental validation is proposed as well.

Kriga, Adoum; Allassem, Desire [Universite de Lyon, F-42023 Saint Etienne (France); Universite de Saint Etienne, Jean Monnet, F-42023 Saint Etienne (France); LT2C, F-42023 Saint Etienne (France); Soultan, Malloum [Universite de N' Djamena N' Djamena (Chad); Chatelon, Jean-Pierre; Siblini, Ali [Universite de Lyon, F-42023 Saint Etienne (France); Universite de Saint Etienne, Jean Monnet, F-42023 Saint Etienne (France); LT2C, F-42023 Saint Etienne (France); Allard, Bruno [Laboratoire Ampere INSA-Lyon 20, avenue Einstein 69621 Villeurbanne Cedex France (France); Rousseau, Jean Jacques, E-mail: rousseau@univ-st-etienne.fr [Universite de Lyon, F-42023 Saint Etienne (France); Universite de Saint Etienne, Jean Monnet, F-42023 Saint Etienne (France); LT2C, F-42023 Saint Etienne (France)

2012-07-15

163

Layered tungsten oxide-based organic/inorganic hybrid materials I: Infrared and Raman study  

CERN Multimedia

Tungsten oxide-organic layered hybrid materials have been studied by infrared and Raman spectroscopy, and demonstrate a difference in bonding nature as the length of the interlayer organic `spacer' molecule is increased. Ethylenediamine-tungsten oxide clearly displays a lack of terminal -NH3^+ ammonium groups which appear in hybrids with longer alkane molecules, thus indicating that the longer chains are bound by electrostatic interactions as well as or in place of the hydrogen bonding that must be present in the shorter chain ethylenediamine hybrids. The presence of organic molecules between the tungsten oxide layers, compared with the layered tungstic acid H2WO4, shows a decrease in the apical W=O bond strength, as might be expected from the aforementioned electrostatic interaction.

Ingham, B

2004-01-01

164

Sacrificial charge and the spectral resolution performance of the Chandra Advanced CCD Imaging Spectrometer  

CERN Document Server

Soon after launch, the Advanced CCD Imaging Spectrometer (ACIS), one of the focal plane instruments on the Chandra X-ray Observatory, suffered radiation damage from exposure to soft protons during passages through the Earth's radiation belts. The ACIS team is continuing to study the properties of the damage with an emphasis on developing techniques to mitigate charge transfer inefficiency (CTI) and spectral resolution degradation. A post-facto CTI corrector has been developed which can effectively recover much of the lost resolution. Any further improvements in performance will require knowledge of the location and amount of sacrificial charge - charge deposited along the readout path of an event which fills electron traps and changes CTI. We report on efforts by the ACIS Instrument team to characterize which charge traps cause performance degradation and the properties of the sacrificial charge seen on-orbit. We also report on attempts to correct X-ray pulseheights for the presence of sacrificial charge.

Grant, C E; La Marr, B; Bautz, M W; Grant, Catherine E.; Prigozhin, Gregory Y.; Marr, Beverly La; Bautz, Mark W.

2002-01-01

165

Polycrystalline SiC as source material for the growth of fluorescent SiC layers  

DEFF Research Database (Denmark)

Polycrystalline doped SiC act as source for fluorescent SiC. We have studied the growth of individual grains with different polytypes in the source material. We show an evolution and orientation of grains of different polytypes in polycrystalline SiC ingots grown by the Physical Vapor Transport method. The grain influence on the growth rate of fluorescent SiC layers grown by a sublimation epitaxial process is discussed in respect of surface kinetics.

Kaiser, M.; Hupfer, T.

2013-01-01

166

A spiro-configured ambipolar host material for impressively efficient single-layer green electrophosphorescent devices.  

UK PubMed Central (United Kingdom)

A spiro-configured bipolar molecule (CSC) that possesses high triplet energy, suitable energy levels, and balanced ambipolar carrier mobilities was successfully applied as an efficient host material, compatible with various iridium-based green phosphors, to realize highly efficient single-layer PhOLEDs of a maximum external quantum efficiency up to 8.3% (31.4 cd A(-1)) at a practical brightness of 1000 cd m(-2) (8 V).

Hung WY; Wang TC; Chiu HC; Chen HF; Wong KT

2010-09-01

167

Grafted, cross-linked carbon black as a double-layer capacitor electrode material  

Energy Technology Data Exchange (ETDEWEB)

Isocyanate prepolymers readily react with oxidic functional groups on carbon black. On carbon black grafted with diisocyanates, reactive isocyanate groups are available for cross-linking to a polyurethane system. This cross-linked carbon black was considered as a new active material for electrochemical electrodes. Active material for electric double-layer capacitor electrodes was produced which had values of specific capacitance of up to 200 F/g. Cross-linking efficiencies of up to 58 % of the polymers utilised were achieved. (author)

Richner, R.; Mueller, S.; Wokaun, A.

2001-03-01

168

Development of PZT materials, fabrication and characterization of multi layered actuators for aerospace applications  

Science.gov (United States)

Piezo Electric Materials capable of performing both "sensing" and "actuation" are known as smart materials. These materials produce electric charges on application of mechanical stress (as sensor) or undergo dimensional change when subjected to an electric field (as actuator). PZTs are preferred because of their (i) fast response time, (ii) high frequency response, (iii) precession control etc. Piezo sensors and actuators are used for various applications e.g. for vibration control of aerospace structures, development of smart aeroplane wings / morphing structures, precision flow control of propellants in space vehicles, fuel flow control in automobile engines, energy harvesting etc. At NAL, efforts are being made to prepare PZT materials, multi-layered actuators are currently fabricated and characterized for aerospace applications.

Panda, P. K.

2012-07-01

169

Material and shape optimization for multi-layered vocal fold models using transient loadings.  

UK PubMed Central (United Kingdom)

Commonly applied models to study vocal fold vibrations in combination with air flow distributions are self-sustained physical models of the larynx consisting of artificial silicone vocal folds. Choosing appropriate mechanical parameters and layer geometries for these vocal fold models while considering simplifications due to manufacturing restrictions is difficult but crucial for achieving realistic behavior. In earlier work by Schmidt et al. [J. Acoust. Soc. Am. 129, 2168-2180 (2011)], the authors presented an approach in which material parameters of a static numerical vocal fold model were optimized to achieve an agreement of the displacement field with data retrieved from hemilarynx experiments. This method is now generalized to a fully transient setting. Moreover in addition to the material parameters, the extended approach is capable of finding optimized layer geometries. Depending on chosen material restriction, significant modifications of the reference geometry are predicted. The additional flexibility in the design space leads to a significantly more realistic deformation behavior. At the same time, the predicted biomechanical and geometrical results are still feasible for manufacturing physical vocal fold models consisting of several silicone layers. As a consequence, the proposed combined experimental and numerical method is suited to guide the construction of physical vocal fold models.

Schmidt B; Leugering G; Stingl M; Hu?ttner B; Agaimy A; Do?llinger M

2013-08-01

170

Biomacromolecule immobilization and self-assembled monolayer chemistry on atomic layer deposited metal oxide materials  

Science.gov (United States)

Many biotechnology applications involve interfacing proteins, DNA and other macromolecules to non-biological material surfaces acting as supports. Support materials employed for this purpose span the periodic table and range from polymeric membranes/hydrogels to metals and ceramics, for example gold and hydroxyapatite. Lab-on-a-chip and other sensing/detection applications based on lithography and semiconductor technology typically rely on alkanethiol and organosilane chemistry to immobilize biological material to gold and silica. While successful in many instances, organosilane chemistry offers limited options for orthogonal chemistry and often results in multilayer film buildup. Self-assembly on gold is straight forward but gold is often undesirable from a device perspective. Recent developments in atomic layer deposition (ALD) allow fabrication of high quality thin films of alumina and high-k oxide materials that are compatible with clean room operations and are interesting emerging materials for integrated optical, electronic and biological applications. Here we will show alternative self-assembly chemistries on ALD materials for biological immobilization than those used on gold/silica and also demonstrate direct biological interfacing to high-K materials for potential use in bioscreening and detection.

Bergkvist, Magnus

2009-10-01

171

Layered double hydroxide-like materials: nanocomposites for use in concrete  

International Nuclear Information System (INIS)

[en] Nitrobenzoic acid (NBA), naphthalene-2, 6-disulfonic acid (26NS), and naphthalene-2 sulfonic acid (2NS) salts were intercalated into a layered double hydroxide-like host material (LDH). The intercalation process was achieved by anion exchange of nitrates in the host material, Ca2Al(OH)6NO3, nH2O (CaAl LDH), which was prepared by a coprecipitation technique. The resulting organo derivatives CaAlNBA LDH, CaAl26NS LDH, and CaAl2NS LDH produced a tilted orientation of NBA and 26NS anions in the interlayer space, while 2NS anions induced a perpendicular bilayer arrangement. Materials characterization was carried out using X-ray diffraction (XRD), IR-spectroscopy, thermal analysis, and scanning electron microscopy (SEM). These preliminary results open up a new direction towards the synthesis of nanocomposites using polymeric entities and layered materials for future applications in cement and concrete science, e.g., control of the effect of admixtures on the kinetics of cement hydration by programming their temporal release

2004-01-01

172

Method for preparing galvanic deposit calcium phosphorus mineralized layer superfine fibre bone material  

UK PubMed Central (United Kingdom)

The invention relates to a method for preparing superfine fiber bone materials of an electrodeposition calcium phosphate mineralized layer, which comprises the following steps: firstly, high-polymer superfine fibers are prepared on the surface of a metal electrode by adoption of electrostatic spinning and taken as an electrochemical deposition template a layer of bone salt ingredients which are rich in calcium and phosphor is deposited on the surface of the fibers by the constant-voltage or constant-current deposition technology mineralized superfine fibers are soaked into 0.1 to 1.0 mol per liter of NaOH solution for 1 to 24 hours mineralized electro spinning fibers are subjected to die stamping into blocks under the pressure of between 10 and 40 MPa and the porous bone materials with a porosity between 50 and 90 percent and a pore diameter between 50 and 500 micrometers are processed by the salt particle leaching/gas foaming technology, and are used for bone defect restoration after freeze-drying sterilization. The porous bone materials prepared by the method have better biocompatibility and the electrochemical deposition technology can prepare organic-inorganic composite materials with higher bone salt content within a shorter period and the preparation time is short and the preparation conditions are mild.

CHUANGLONG HE; LIJUN QIU; XIAOHONG XU; HONGSHENG WANG; XIUMEI MO

173

Preparation of thin layer materials with macroporous microstructure for SOFC applications  

International Nuclear Information System (INIS)

A facile and versatile method using polymethyl methacrylate (PMMA) microspheres as pore formers has been developed to prepare thin layer oxide materials with controlled macroporous microstructure. Several mixed oxides with fluorite and perovskite-type structures, i.e. doped zirconia, ceria, ferrites, manganites, and NiO-YSZ composites have been prepared and characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption and mercury porosimetry. The synthesised materials are nanocrystalline and present a homogeneous pore distribution and relatively high specific surface area, which makes them interesting for SOFC and catalysis applications in the intermediate temperature range. - Graphical abstract: Thin films materials of mixed oxides with potential application in SOFC devices have been prepared with macroporous microstructure using PMMA microspheres as pore formers. Display Omitted

2008-01-01

174

Heat transfer materials with porous alumina layer; Takoshitsu arumina so wo yusuru dennetsu zairyo  

Energy Technology Data Exchange (ETDEWEB)

Recently, treatment method which allow to increase surface area of alumite coat having been developed, alumite material has converted into heat transfer material having new alumina layer and development of various applications has become possible. BET surface area of an Al plate immediately after anodic oxidation by chromic acid is 3.5m{sup 2}/g, but this area increase to 33 m{sup 2} by sealing through hydration at 80{degree}C, and still more, turning out to the porous {gamma}-alumina layer by baking at 300{degree}C, it reach 176 m{sup 2}. This surface area being comparable to that of common catalysts, application as catalyst support turned out possible. Since the base metal is Al having high heat conductivity, when the catalyst layer is gotten formed by this treatment method on the inside of a heat exchanger, film coefficient of heat transfer near the catalyst came into 140 times as much as usual reactor packed with granular catalysts. Various developments such as reactors combined with chemical heat pumps, fin-type reactors and application for hydrogenation-dehydrogenation, etc. are expected. 9 refs., 14 figs., 1 tab.

Kameyama, H. [Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology

1995-09-01

175

Thermal properties measurement of dry bulk materials with a cylindrical three layers device.  

UK PubMed Central (United Kingdom)

This paper presents a new method dedicated to thermal properties (conductivity and diffusivity) measurement of dry bulk materials including powders. The cylindrical three layers experimental device (brass?bulk material?stainless steel) and the principle of the measurement method based on a crenel thermal excitation are presented. The one-dimensional modeling of the system is used for a sensitivity analysis and to calculate the standard deviation of the estimation error. Experimental measurements are carried out on three bulk materials: glass beads, cork granules, and expanded polystyrene beads. The estimated thermal properties are compared with the values obtained by other measurement methods. Results are in good agreement with theoretical predictions: both thermal conductivity and diffusivity can be estimated with a good accuracy for low density material like cork granules or expanded polystyrene beads since only thermal diffusivity can be estimated for heavier materials like glass beads. It is finally shown that this method like all transient methods is not suited to the thermal characterization of wet bulk materials.

Jannot Y; Degiovanni A

2013-09-01

176

Thermal properties measurement of dry bulk materials with a cylindrical three layers device  

Science.gov (United States)

This paper presents a new method dedicated to thermal properties (conductivity and diffusivity) measurement of dry bulk materials including powders. The cylindrical three layers experimental device (brass/bulk material/stainless steel) and the principle of the measurement method based on a crenel thermal excitation are presented. The one-dimensional modeling of the system is used for a sensitivity analysis and to calculate the standard deviation of the estimation error. Experimental measurements are carried out on three bulk materials: glass beads, cork granules, and expanded polystyrene beads. The estimated thermal properties are compared with the values obtained by other measurement methods. Results are in good agreement with theoretical predictions: both thermal conductivity and diffusivity can be estimated with a good accuracy for low density material like cork granules or expanded polystyrene beads since only thermal diffusivity can be estimated for heavier materials like glass beads. It is finally shown that this method like all transient methods is not suited to the thermal characterization of wet bulk materials.

Jannot, Y.; Degiovanni, A.

2013-09-01

177

Elemental analysis on reaction layers formed in the core materials interaction at high temperatures  

Energy Technology Data Exchange (ETDEWEB)

To obtain the fundamental data to evaluate the initial stage of the core degradation during a severe accident in LWRs, quantitative elemental analyses with SEM-EDX/WDX were performed on reaction layers formed at interfaces between core materials in laboratory tests at high temperatures. The reaction layers analyzed were those formed in the reactions of Zircaloy-4/Inconel-718, Zircaloy-4/stainless steel type 304, Ag-In-Cd alloy/Zircaloy-4, B{sub 4}C/stainless steel type 304, and B{sub 4}C/Zircaloy-4. The results indicated that initiation temperatures of these reactions and discontinuities of the temperature dependence of the reaction rate were obviously connected with eutectic formations. (author).

Nagase, Fumihisa; Uetsuka, Hiroshi; Otomo, Takashi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1995-11-01

178

Effects of shroud gas injection on material properties of tungsten layers coated by plasma spraying  

International Nuclear Information System (INIS)

Coated tungsten layers on stainless steel substrates were are produced by atmosphere plasma spraying. A shroud gas injection method was employed to reduce the ambient air entrainment into the plasma jets. The effects of shroud gas on the material properties of the tungsten layers were investigated by finding the dependence of oxide content, coating thickness and porosity on the injection velocity, shielding width, and mass flux of the shroud gas. The high injection velocity was more effective than thick shroud shielding in protecting the plasma jets from ambient air engulfment, and the mass flux of the shroud gas showed negligibly small effects on the suppression of air entrainment. Therefore, in order to produce a thick tungsten coating with low porosity and oxide contents, high injection velocity with a limited flow rate is a desirable operating condition for shroud gas injection in atmospheric plasma spraying.

2010-09-01

179

Emanation thermal analysis for characterization of surface and near surface layers of advanced materials  

International Nuclear Information System (INIS)

A non traditional method, called emanation thermal analysis (ETA), was used the for characterization of surface and near surface layers of SiC based materials. This method consists in the measurement of the release of inert gas (radon) from the samples previously labeled to the depth of several tens of nanometers with the inert gas atoms. The ETA results brought about information about microstructure changes and transport properties of SiC/SiCf composites on heating in the range 30-1300degC in argon and air, respectively. The annealing of structure irregularities which served as diffusion paths for radon was evaluated. The temperature range of the formation and crystallization of the silica layer resulting after oxidation of the SiC/SiCf sample on heating in air was determined from the ETA results. (author)

2003-01-01

180

The influence of Ti and Sr alloying elements on electrochemical properties of aluminum sacrificial anodes  

Energy Technology Data Exchange (ETDEWEB)

Aluminum sacrificial anodes are widely used in cathodic protection of alloys in seawater. The interesting properties due to low specific weight, low electrode potential and high current capacity are often hindered by the presence of a passive oxide film which causes several difficulties in their practical application. In this investigation, the electrochemical behavior of Al- 5Zn-0.02In sacrificial anode is studied in 3 wt. % sodium chloride solution. The experiments focused on the influence of Ti and Sr as alloying elements on electrochemical behavior of aluminum sacrificial anode. Ti and Sr are used in different concentrations from 0.03 to 0.1 wt.% 0.01 to 0.05 wt.%, respectively. NACE efficiency and polarization tests are used in this case. It is shown that by using 0.03 wt.% Ti and 0.01 wt.% Sr as the alloying elements to investigate the anodic behavior of the anodes, homogeneous microstructures are obtained which results in improvement of electrochemical properties of aluminum sacrificial anode such as current capacity and anode efficiency. (authors)

Saremi, M.; Sina, H.; Keyvani, A.; Emamy, M. [Metallurgy and Materials Department, University of Tehran, P.O. Box 11365/4563, Tehran (Iran)

2004-07-01

 
 
 
 
181

Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers) for Aluminum Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportati...

Shashi S. Pathak; Sharathkumar K. Mendon; Michael D. Blanton; James W. Rawlins

182

Fabrication of Porous Hydroxyapatite through Combination of Sacrificial Template and Direct Foaming Techniques  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The porous hydroxyapatite (HA) bioceramics were prepared through combination of sacrificial template and direct foaming techniques using PMMA granules (varied from 5 to 50wt% in content) as a template and H2O2 solution (varied from 5 to 30wt% in concentration) as a foaming agent, respectively. The e...

Sujin Woottichaiwat; Somchai Puajindanetr; Serena M Best

183

Work function and electron affinity of some layered transition metal dichalcogenide materials  

International Nuclear Information System (INIS)

Work function and electron affinity values of various semiconducting and metallic layered transition metal dichalcogenides (TMDCs) which might be suitable for the photovoltaic applications (such as ZrSxSe2-x where 0?x?2, HfSe2, HfS2, TiTe2, NbTe2, TaS2) have been measured using photoemission spectroscopy and vibrating capacitor Kelvin probe techniques. All samples were single crystals grown by the chemical vapour transport method with iodine as a transport agent. The measured values are compared to the previously reported empirical and calculated values based on various band models, and proved good agreement for most of the materials.

2009-01-01

184

Microwave absorption properties of carbon nanocoils coated with highly controlled magnetic materials by atomic layer deposition.  

UK PubMed Central (United Kingdom)

In this work, atomic layer deposition is applied to coat carbon nanocoils with magnetic Fe(3)O(4) or Ni. The coatings have a uniform and highly controlled thickness. The coated nanocoils with coaxial multilayer nanostructures exhibit remarkably improved microwave absorption properties compared to the pristine carbon nanocoils. The enhanced absorption ability arises from the efficient complementarity between complex permittivity and permeability, chiral morphology, and multilayer structure of the products. This method can be extended to exploit other composite materials benefiting from its convenient control of the impedance matching and combination of dielectric-magnetic multiple loss mechanisms for microwave absorption applications.

Wang G; Gao Z; Tang S; Chen C; Duan F; Zhao S; Lin S; Feng Y; Zhou L; Qin Y

2012-12-01

185

Microwave absorption properties of carbon nanocoils coated with highly controlled magnetic materials by atomic layer deposition.  

Science.gov (United States)

In this work, atomic layer deposition is applied to coat carbon nanocoils with magnetic Fe(3)O(4) or Ni. The coatings have a uniform and highly controlled thickness. The coated nanocoils with coaxial multilayer nanostructures exhibit remarkably improved microwave absorption properties compared to the pristine carbon nanocoils. The enhanced absorption ability arises from the efficient complementarity between complex permittivity and permeability, chiral morphology, and multilayer structure of the products. This method can be extended to exploit other composite materials benefiting from its convenient control of the impedance matching and combination of dielectric-magnetic multiple loss mechanisms for microwave absorption applications. PMID:23171130

Wang, Guizhen; Gao, Zhe; Tang, Shiwei; Chen, Chaoqiu; Duan, Feifei; Zhao, Shichao; Lin, Shiwei; Feng, Yuhong; Zhou, Lei; Qin, Yong

2012-12-05

186

Nanohybrid-layered double hydroxides/urease materials: Synthesis and application to urea biosensors  

Energy Technology Data Exchange (ETDEWEB)

Nanohybrid [ZnAl]-layered double hydroxides/urease were prepared for the first time using the coprecipitation of enzyme and inorganic matrix. By varying the respective amount of urease and LDH, we obtained hybrid materials with various amount and dispersion rate of active biomolecules. X-ray diffraction and infrared spectroscopy confirm the preservation of the structure of each partner while the morphology properties are in good agreement with the permeability study. These new nanohybrids were applied for the development of urea biosensors. Biosensor responses to urea additions were obtained using capacitance (C vs. V) measurements at urease-LDH biofilm deposited on an insulated semiconductor (IS) structure.

Vial, S. [Laboratoire de Materiaux Inorganiques, CNRS UMR 6002, FR 2404, Universite Blaise Pascal, Aubiere (France); Forano, C. [Laboratoire de Materiaux Inorganiques, CNRS UMR 6002, FR 2404, Universite Blaise Pascal, Aubiere (France)]. E-mail: claude.forano@univ-bpclermont.fr; Shan, D. [Laboratoire d' Electrochimie Organique et de Photochimie redox UMR CNRS 5630, ICMG FR 2607, Universite Joseph Fourier, Grenoble (France); Mousty, C. [Laboratoire d' Electrochimie Organique et de Photochimie redox UMR CNRS 5630, ICMG FR 2607, Universite Joseph Fourier, Grenoble (France); Barhoumi, H. [CEGELY UMR 5005, Ecole Centrale de Lyon, Ecully (France); Martelet, C. [CEGELY UMR 5005, Ecole Centrale de Lyon, Ecully (France); Jaffrezic, N. [CEGELY UMR 5005, Ecole Centrale de Lyon, Ecully (France)

2006-03-15

187

Material technology trends to improve multi-layer coatings: Challenges to traditional thinking  

Energy Technology Data Exchange (ETDEWEB)

Current global acceptance of the three layer polyethylene coating system for the exterior coating of steel pipelines (for almost any environment on-shore/off-shore for oil, gas or water pipelines) has helped to expand the present coating use. The focus of this paper will be on coating material changes by technology, to up-grade the end use of the coating system and to present those changes to the engineering and corrosion community to the benefit of the end user or client.

Cox, J.W. [DuPont Canada Inc., Calgary, Alberta (Canada); Grimshaw, D. [Jotun Powder Coatings Ltd., Scunthorpe (United Kingdom); D`Agostino, C. [Novacor Chemicals Ltd., Mississauga, Ontario (Canada)

1996-12-31

188

X-ray fluorescence of layered synthetic materials with interfacial roughness  

International Nuclear Information System (INIS)

Measurements of x-ray fluorescence versus grazing incidence angle at fixed incoming photon energy can provide useful information on surface and interfacial microstructure. A matrix formulation suitable for analysis of radiant energy flow inside a layered material, and hence angular fluorescence emission, is presented, and a vector scattering model is employed to account for the effect of interfacial roughness. Good agreement between experimental results of x-ray fluorescence yield and the model calculations has been obtained in a semiconductor heterostructure and a superlattice system.

1988-01-01

189

Nanohybrid-layered double hydroxides/urease materials: Synthesis and application to urea biosensors  

International Nuclear Information System (INIS)

[en] Nanohybrid [ZnAl]-layered double hydroxides/urease were prepared for the first time using the coprecipitation of enzyme and inorganic matrix. By varying the respective amount of urease and LDH, we obtained hybrid materials with various amount and dispersion rate of active biomolecules. X-ray diffraction and infrared spectroscopy confirm the preservation of the structure of each partner while the morphology properties are in good agreement with the permeability study. These new nanohybrids were applied for the development of urea biosensors. Biosensor responses to urea additions were obtained using capacitance (C vs. V) measurements at urease-LDH biofilm deposited on an insulated semiconductor (IS) structure

2004-12-01

190

Study on UV-shielding mechanism of layered double hydroxide materials.  

UK PubMed Central (United Kingdom)

The development of UV-shielding materials has attracted considerable attention in the field of coatings and sunscreen. This paper reports the UV-shielding mechanism of layered double hydroxide (LDH) materials in terms of chemical composition, structure and morphology, by using (LDH/PAA)n films (n stands for bilayer number) through alternate LBL assembly of LDH nanoparticles and poly(acrylic acid) (PAA) on quartz substrates as a model system. A combination investigation based on experimental and theoretical study demonstrates that the maximum UV scattering can be achieved when ?/d ? 1.98; the introduction of Zn element is an effective way to tune the electron structure, band gap, transition mode and resulting UV-shielding property of LDH materials. A UV-shielding efficiency as high as 95% can be obtained by modulating the particle size, composition and thickness of the LDHs. Furthermore, the UV anti-aging capacity of LDH-modified bitumen was studied, which demonstrates a large improvement in UV-resistance performance of bitumen by the incorporation of LDH materials. Therefore, this work systematically discloses the relationship between UV-shielding property and chemical/structural parameters of LDH materials, which can be potentially used as anti-aging agents in various organic matrices and polymer areas.

Shi W; Lin Y; Zhang S; Tian R; Liang R; Wei M; Evans DG; Duan X

2013-09-01

191

Study on UV-shielding mechanism of layered double hydroxide materials.  

UK PubMed Central (United Kingdom)

The development of UV-shielding materials has attracted considerable attention in the field of coatings and sunscreen. This paper reports the UV-shielding mechanism of layered double hydroxide (LDH) materials in terms of chemical composition, structure and morphology, by using (LDH/PAA)n films (n stands for bilayer number) through alternate LBL assembly of LDH nanoparticles and poly(acrylic acid) (PAA) on quartz substrates as a model system. A combination investigation based on experimental and theoretical study demonstrates that the maximum UV scattering can be achieved when ?/d ? 1.98; the introduction of Zn element is an effective way to tune the electron structure, band gap, transition mode and resulting UV-shielding property of LDH materials. A UV-shielding efficiency as high as 95% can be obtained by modulating the particle size, composition and thickness of the LDHs. Furthermore, the UV anti-aging capacity of LDH-modified bitumen was studied, which demonstrates a large improvement in UV-resistance performance of bitumen by the incorporation of LDH materials. Therefore, this work systematically discloses the relationship between UV-shielding property and chemical/structural parameters of LDH materials, which can be potentially used as anti-aging agents in various organic matrices and polymer areas.

Shi W; Lin Y; Zhang S; Tian R; Liang R; Wei M; Evans DG; Duan X

2013-10-01

192

Los Alamos MAWST software layered on Westinghouse Savannah River Company`s nuclear materials accountability system  

Energy Technology Data Exchange (ETDEWEB)

The Los Alamos Safeguards Systems Group`s Materials Accounting With Sequential Testing (MAWST) computer program was developed to fulfill DOE Order 5633.3B requiring that inventory-difference control limits be based on variance propagation or any other statistically valid technique. Westinghouse Savannah River Company (WSRC) developed a generic computerized accountability system, NucMAS, to satisfy accounting and reporting requirements for material balance areas. NucMAS maintains the calculation methods and the measurement information required to compute nuclear material transactions in elemental and isotopic masses by material type code. The Safeguards Systems Group designed and implemented to WSRC`s specifications a software interface application, called NucMASloe. It is a layered product for NucMAS that automatically formats a NucMAS data set to a format compatible with MAWST and runs MAWST. This paper traces the development of NucMASloe from the Software Requirements through the testing and demonstration stages. The general design constraints are described as well as the difficulties encountered on interfacing an external software product (MAWST) with an existing classical accounting structure (NucMAS). The lessons learned from this effort, the design, and some of the software are directly applicable to the Local Area Network Material Accountability System (LANMAS) being sponsored by DOE.

Whitty, W.J.; Smith, J.E. [Los Alamos National Lab., NM (United States); Davis, J.M. Jr. [Westinghouse Savannah River Co., Aiken, SC (United States). Savannah River Site

1995-09-01

193

Study on UV-shielding mechanism of layered double hydroxide materials.  

Science.gov (United States)

The development of UV-shielding materials has attracted considerable attention in the field of coatings and sunscreen. This paper reports the UV-shielding mechanism of layered double hydroxide (LDH) materials in terms of chemical composition, structure and morphology, by using (LDH/PAA)n films (n stands for bilayer number) through alternate LBL assembly of LDH nanoparticles and poly(acrylic acid) (PAA) on quartz substrates as a model system. A combination investigation based on experimental and theoretical study demonstrates that the maximum UV scattering can be achieved when ?/d ? 1.98; the introduction of Zn element is an effective way to tune the electron structure, band gap, transition mode and resulting UV-shielding property of LDH materials. A UV-shielding efficiency as high as 95% can be obtained by modulating the particle size, composition and thickness of the LDHs. Furthermore, the UV anti-aging capacity of LDH-modified bitumen was studied, which demonstrates a large improvement in UV-resistance performance of bitumen by the incorporation of LDH materials. Therefore, this work systematically discloses the relationship between UV-shielding property and chemical/structural parameters of LDH materials, which can be potentially used as anti-aging agents in various organic matrices and polymer areas. PMID:24064552

Shi, Wenying; Lin, Yanjun; Zhang, Shitong; Tian, Rui; Liang, Ruizheng; Wei, Min; Evans, David G; Duan, Xue

2013-10-01

194

Process for forming one or more substantially pure layers in substrate material using ion implantation  

International Nuclear Information System (INIS)

[en] This patent describes a process for forming a substantially pure, monocrystalline layer of an implantable element in a monocrystalline substrate. It comprises selecting an implantable element and a monocrystalline substrate to be implanted wherein, at the temperature to be used for the implantation and annealing; the solubilities of the implantable element and the substrate material in one another are less than 10 at. %; and no intermediate phases containing both the implantable element and the substrate material exist; implanting, at a temperature ranging from about -196 degrees C to about 10 degrees C below the melting point of the substrate, at least about 5 x 1016 atoms/cm2 of the implantable element in the substrate; and annealing the implanted substrate at a temperature ranging from about 20 degrees C to about 10 degrees C below the melting point of the substrate for a period of time of about 1 second to about 100 hours

1990-12-11

195

Process for forming one or more substantially pure layers in substrate material using ion implantation  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a process for forming a substantially pure, monocrystalline layer of an implantable element in a monocrystalline substrate. It comprises selecting an implantable element and a monocrystalline substrate to be implanted wherein, at the temperature to be used for the implantation and annealing; the solubilities of the implantable element and the substrate material in one another are less than 10 at. %; and no intermediate phases containing both the implantable element and the substrate material exist; implanting, at a temperature ranging from about {minus}196{degrees} C to about 10{degrees} C below the melting point of the substrate, at least about 5 {times} 10{sup 16} atoms/cm{sup 2} of the implantable element in the substrate; and annealing the implanted substrate at a temperature ranging from about 20{degrees} C to about 10{degrees} C below the melting point of the substrate for a period of time of about 1 second to about 100 hours.

Musket, R.G.; Brown, D.W.; Munir, Z.A.

1992-06-23

196

OPTIMIZING A PORTABLE MICROWAVE INTERFERENCE SCANNING SYSTEM FOR NONDESTRUCTIVE TESTING OF MULTI-LAYERED DIELECTRIC MATERIALS  

International Nuclear Information System (INIS)

The projected microwave energy pattern, wave guide geometry, positioning methods and process variables have been optimized for use of a portable, non-contact, lap-top computer-controlled microwave interference scanning system on multi-layered dielectric materials. The system can be used in situ with one-sided access and has demonstrated capability of damage detection on composite ceramic armor. Specimens used for validation included specially fabricated surrogates, and ballistic impact-damaged specimens. Microwave data results were corroborated with high resolution direct-digital x-ray imaging. Microwave interference scanning detects cracks, laminar features and material properties variations. This paper presents the details of the system, the optimization steps and discusses results obtained.

2010-02-22

197

Synthesis by a wet chemical route of layered LiMnO{sub 2} cathode materials  

Energy Technology Data Exchange (ETDEWEB)

A wet chemical route to synthesize layered lithium-manganese-oxide (LiMnO{sub 2}) is described, along with the structure and electrochemical performance of this cathode material which may be used in lithium ion rechargeable batteries in place of lithium-copper-oxide or lithium-nickel oxide. Compared with the conventional ion exchange method, the proposed wet method of preparation is claimed to be significantly easier, less costly, and without significant environmental problems. However, to obtain LiMnO{sub 2} of high purity it is essential to strictly control the preparation process, especially the pH value of the mixed precursor solutions. LiMnO{sub 2} prepared by the proposed method has been shown to have large capacity and long cyclic life. The structure and electrochemical performance of the material are also described, including the actual formulas of two samples determined by powder X-ray diffraction. 13 refs., 2 tabs., 6 figs.

Su, Y.; Zou, Q.; Guo, M.; Liu, J.; Yu, P.; Su, J. [Central South University, School oof Materials Science and Engineering, Changsha (China); Wang, Y. [Tsinghua University, Institute of Nuclear Energy Technology, Beijin (China)

2004-01-01

198

Cooperation of micro- and meso-porous carbon electrode materials in electric double-layer capacitors  

Energy Technology Data Exchange (ETDEWEB)

The capacitive characteristics of micro- and meso-porous carbon materials have been compared in cyclic voltammetric studies and galvanostatic charge-discharge tests. Meso-porous carbon can keep certain high capacitance values at high scan rates, whereas micro-porous carbon possesses very high capacitance values at low scan rates but fades quickly as the scan rate rises up. For better performance of electric double-layer capacitors (EDLCs), the cooperative application of both kinds of carbon materials has been proposed in the following two ways: mixing both kinds of carbons in the same electrode or using the asymmetric configuration of carbon electrodes in the same EDLC. The cooperative effect on the electrochemical performance has also been addressed. (author)

Zheng, Cheng [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, Jilin Province (China); Graduate University of Chinese Academy of Sciences, Beijing 100039 (China); Qi, Li; Wang, Hongyu [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022, Jilin Province (China); Yoshio, Masaki [Advanced Research Center, Saga University, 1341 Yoga-machi, Saga 840-0047 (Japan)

2010-07-01

199

Investigation of epitaxial silicon layers as a material for radiation hardened silicon detectors  

International Nuclear Information System (INIS)

Epitaxial grown thick layers (? 100 microm) of high resistivity silicon (Epi-Si) have been investigated as a possible candidate for radiation hardened material for detectors in high-energy physics. As grown Epi-Si layers contain high concentrations (up to 2 x 1012 cm-3) of deep levels compared with that in standard high resistivity bulk Si. After irradiation of test diodes by protons (Ep = 24 GeV) with a fluence of 15 x 1011 cm-2, no additional radiation induced deep traps have been detected. A reasonable explanation is that there is a sink of primary radiation induced defects (interstitial and vacancies), possibly by as-grown defects, in epitaxial layers. The sinking process, however, becomes non-effective at high radiation fluences (1014 cm-2) due to saturation of epitaxial defects by high concentration of radiation induced ones. As a result, at neutron fluences of 1 x 1014 cm-2 the deep level spectrum corresponds to well-known spectrum of radiation induced defects in high resistivity bulk Si. The net effective concentration in the space charge region equals to 3 x 1012 cm-3 after 3 months of room temperature storage and reveals similar annealing behavior for epitaxial as compared to bulk silicon.

1998-01-01

200

Responses of benthic macroinvertebrates to thin-layer disposal of dredged material in Mississippi Sound, USA.  

UK PubMed Central (United Kingdom)

Benthic community responses to thin-layer disposal of dredged material were assessed at three sites in Mississippi Sound, USA. Community composition differed between disposal and reference sites (ANOSIM) for each disposal event. Oweniid sand worms, Amphinomid fire worms, and brittle stars (Ophiuriodea) contributed the most to community distinctions between disposal and reference sites (SIMPER), with higher abundances at the disposal sites. Total infaunal abundance was similar to pre-disposal and reference conditions within 3-10 months of thin-layer disposal. Distinctions in community composition between disposal and reference sites (nMDS) persisted throughout the 16-month study period, but were less pronounced at the site where sediment composition was unchanged by disposal. Size distributions of some taxa (e.g., gastropod and hemichordate) suggest adults recolonized the newly deposited sediments either through vertical migration or lateral immigration from adjacent areas. Thin-layer disposal offers a viable alternative to conventional open-water disposal practices and warrants further exploration for other areas with deeper bathymetries and different hydrodynamic regimes.

Wilber DH; Clarke DG; Rees SI

2007-01-01

 
 
 
 
201

Rotational fluctuations of water confined to layered oxide materials: nonmonotonous temperature dependence of relaxation times.  

Science.gov (United States)

The rotational molecular dynamics of water confined to layered oxide materials with brucite structure was studied by dielectric spectroscopy in the frequency range from 10(-2) to 10(7) Hz and in a broad temperature interval. The layered double hydroxide samples show one relaxation process, which was assigned to fluctuations of water molecules forming a layer, strongly adsorbed to the oxide surface. The temperature dependence of the relaxation rates has an unusual saddlelike shape characterized by a maximum. The model of Ryabov et al. (J. Phys. Chem. B 2001, 105, 1845) recently applied to describe the dynamics of water molecules in porous glasses is employed also for the layered materials. This model assumes two competing effects: rotational fluctuations of water molecules that take place simultaneously with defect formation, allowing the creation of free volume necessary for reorientation. The activation energy of rotational fluctuations, the energy of defect formation, a pre-exponential factor, and the defect concentration are obtained as main parameters from a fit of this model to the data. The values of these parameters were compared with those found for water confined to nanoporous molecular sieves, porous glasses, or bulk ice. Several correlations were discussed in detail, such as the lower the value of the energy of defect formation, the higher the number of defects. The pre-exponential factor increases with increasing activation energy, as an expression of the compensation law, and indicates the cooperative nature of the motional process. The involvement of the surface OH groups and of the oxygen atoms of the interlayer anions in the formation of hydrogen bonds was further discussed. For the birnessite sample, the relaxation processes are probably overlaid by a dominating conductivity contribution, which is analyzed in its frequency and temperature dependence. It is found that the conductivity of birnessite obeys the characteristics of semiconducting disordered materials. Especially the Barton/Nakajima/Namikawa relationship is fulfilled. Analyzing the temperature dependence of the direct current (dc) conductivity sigma0 in detail gives some hint that sigma0(T) has also an unusual saddlelike form. PMID:17536791

Frunza, Ligia; Schönhals, Andreas; Frunza, Stefan; Parvulescu, Vasile I; Cojocaru, Bogdan; Carriazo, Daniel; Martín, Cristina; Rives, Vicente

2007-05-31

202

V(z) curves of layered anisotropic materials for the line-focus acoustic microscope  

Energy Technology Data Exchange (ETDEWEB)

V(z) curves for a line-focus acoustic microscope have been calculated in terms of the characteristic functions of the acoustic lens and the reflectance function of the fluid-loaded specimen. More accurate expressions for the characteristic functions of the acoustic lens are presented by taking account of attenuation in the coupling fluid, the angular dependence of transmission by the antireflection coating on the lens surface, and by making a better estimate of the focal length. The reflectance function has been calculated for anisotropic layers deposited on anisotropic substrates. The calculated V(z) curves have been compared with measurements for isotropic and anisotropic materials, and layered anisotropic materials. The surface acoustic wave velocities obtained from the theoretical and the measured V(z) curves have been compared for the full range of directions of wave propagation. The comparisons of V(z) curves and surface acoustic wave velocities show excellent agreement between theoretical and experimental results. 21 refs., 11 figs., 2 tab.

Lee, Y.C.; Kim, J.O.; Achenbach, J.D. (Northwestern Univ., Evanston, IL (United States))

1993-08-01

203

Characterization of Elastic-plastic Material Properties for IMC Layer of ENEPIG by Using Reverse Algorithm  

Science.gov (United States)

Recently, the reliability assurance of lead-free solder to prevent environmental contamination is quite important issue for chip-scale packaging. Although lots of efforts have been devoted to the solder undergone drop, shear and creep loads, there was a little research on IMC due primarily to its thickness restriction and geometric irregularity. However, the IMC is known as the weakest layer governing failures of the solder joint. The present work is to characterize realistic material properties of the IMC for ENEPIG process. Lee's modified reverse algorithm was adopted to determine elastic-plastic stress-strain curve and so forth, after examining several methods, which requires inherently elastic data. In this context, a series of nano-indentation tests as well as corresponding simulations were carried out by changing indentation depths from 200 to 400 nm and strain rates from 0.05 to 0.10 1/s. It would be conclude that effect of strain rate is relatively small and IMC layer should be more than 5 times of indentation depth when using the recommended method, which are applicable to generate realistic material properties for further diverse structural integrity simulations.

Kim, Jong-Min; Lee, Hyun-Boo; Chang, Yoon-Suk; Choi, Jae-Boong; Kim, Young-Jin; Ji, Kum-Young

2010-05-01

204

Assessment of doses caused by electrons in thin layers of tissue-equivalent materials, using MCNP.  

Science.gov (United States)

Absorbed doses caused by electron irradiation were calculated with Monte Carlo N-Particle transport code (MCNP) for thin layers of tissue-equivalent materials. The layers were so thin that the calculation of energy deposition was on the border of the scope of MCNP. Therefore, in this article application of three different methods of calculation of energy deposition is discussed. This was done by means of two scenarios: in the first one, electrons were emitted from the centre of a sphere of water and also recorded in that sphere; and in the second, an irradiation with the PTB Secondary Standard BSS2 was modelled, where electrons were emitted from an (90)Sr/(90)Y area source and recorded inside a cuboid phantom made of tissue-equivalent material. The speed and accuracy of the different methods were of interest. While a significant difference in accuracy was visible for one method in the first scenario, the difference in accuracy of the three methods was insignificant for the second one. Considerable differences in speed were found for both scenarios. In order to demonstrate the need for calculating the dose in thin small zones, a third scenario was constructed and simulated as well. The third scenario was nearly equal to the second one, but a pike of lead was assumed to be inside the phantom in addition. A dose enhancement (caused by the pike of lead) of ?113 % was recorded for a thin hollow cylinder at a depth of 0.007 cm, which the basal-skin layer is referred to in particular. Dose enhancements between 68 and 88 % were found for a slab with a radius of 0.09 cm for all depths. All dose enhancements were hardly noticeable for a slab with a cross-sectional area of 1 cm(2), which is usually applied to operational radiation protection. PMID:23576794

Heide, Bernd

2013-04-10

205

Assessment of doses caused by electrons in thin layers of tissue-equivalent materials, using MCNP.  

UK PubMed Central (United Kingdom)

Absorbed doses caused by electron irradiation were calculated with Monte Carlo N-Particle transport code (MCNP) for thin layers of tissue-equivalent materials. The layers were so thin that the calculation of energy deposition was on the border of the scope of MCNP. Therefore, in this article application of three different methods of calculation of energy deposition is discussed. This was done by means of two scenarios: in the first one, electrons were emitted from the centre of a sphere of water and also recorded in that sphere; and in the second, an irradiation with the PTB Secondary Standard BSS2 was modelled, where electrons were emitted from an (90)Sr/(90)Y area source and recorded inside a cuboid phantom made of tissue-equivalent material. The speed and accuracy of the different methods were of interest. While a significant difference in accuracy was visible for one method in the first scenario, the difference in accuracy of the three methods was insignificant for the second one. Considerable differences in speed were found for both scenarios. In order to demonstrate the need for calculating the dose in thin small zones, a third scenario was constructed and simulated as well. The third scenario was nearly equal to the second one, but a pike of lead was assumed to be inside the phantom in addition. A dose enhancement (caused by the pike of lead) of ?113 % was recorded for a thin hollow cylinder at a depth of 0.007 cm, which the basal-skin layer is referred to in particular. Dose enhancements between 68 and 88 % were found for a slab with a radius of 0.09 cm for all depths. All dose enhancements were hardly noticeable for a slab with a cross-sectional area of 1 cm(2), which is usually applied to operational radiation protection.

Heide B

2013-01-01

206

Synthesis and Properties of Layered Organic-inorganic Hybrid Material: Zn-Al Layered Double Hydroxide-dioctyl Sulfosuccinate Nanocomposite  

International Nuclear Information System (INIS)

A layered organic-inorganic hybrid nanocomposite was prepared by using a surfactant, dioctyl sulphosuccinate (DSS) as a guest in Zn-Al layered double hydroxide (LDH) inorganic host by a self-assembly technique. The Zn-Al ratio of the mother liquor was kept constant at 4 at the beginning of the synthesis. Powder X-ray diffractogram shows that the basal spacing of the Zn-Al LDH with sulphate as the intergallery anion (ZASUL) expanded from 11.0 to 26.3 A to accommodate the DSS surfactant anion for the formation of the Zn-Al LDH-DSS layered organic-inorganic hybrid nanocomposite (ZADON). It was also found that the BET surface area reduced by about 90%, from 22.5 to 2.2 m2/g, for ZASUL and ZADON, respectively if 0.1 M DSS was used for the synthesis of the latter.

2000-01-01

207

Synthesis and Properties of Layered Organic-inorganic Hybrid Material: Zn-Al Layered Double Hydroxide-dioctyl Sulfosuccinate Nanocomposite  

Energy Technology Data Exchange (ETDEWEB)

A layered organic-inorganic hybrid nanocomposite was prepared by using a surfactant, dioctyl sulphosuccinate (DSS) as a guest in Zn-Al layered double hydroxide (LDH) inorganic host by a self-assembly technique. The Zn-Al ratio of the mother liquor was kept constant at 4 at the beginning of the synthesis. Powder X-ray diffractogram shows that the basal spacing of the Zn-Al LDH with sulphate as the intergallery anion (ZASUL) expanded from 11.0 to 26.3 A to accommodate the DSS surfactant anion for the formation of the Zn-Al LDH-DSS layered organic-inorganic hybrid nanocomposite (ZADON). It was also found that the BET surface area reduced by about 90%, from 22.5 to 2.2 m{sup 2}/g, for ZASUL and ZADON, respectively if 0.1 M DSS was used for the synthesis of the latter.

Mohd Zobir bin Hussein, E-mail: mzobir@sfsas.upm.edu.my; Tan Kim Hwa [Universiti Putra Malaysia, Multifunctional Materials for Industrial Application (MULIA) Research Group, Department of Chemistry (Malaysia)], E-mail: mzobir@sfsas.upm.edu.my

2000-09-15

208

Cleaning of conveyor belt materials using ultrasound in a thin layer of water.  

UK PubMed Central (United Kingdom)

Cleaning of conveyor belts in the food industry is imperative for preventing the buildup of microorganisms that can contaminate food. New technologies for decreasing water and energy consumption of cleaning systems are desired. Ultrasound can be used for cleaning a wide range of materials. Most commonly, baths containing fairly large amounts of water are used. One possibility to reduce water consumption is to use ultrasonic cavitation in a thin water film on a flat surface, like a conveyor belt. In order to test this possibility, a model system was set up, consisting of an ultrasound transducer/probe with a 70-mm-diameter flat bottom, operating at 19.8 kHz, and contaminated conveyor belt materials in the form of coupons covered with a thin layer of water or water with detergent. Ultrasound was then applied on the water surface at different power levels (from 46 to 260 W), exposure times (10 and 20 s), and distances (2 to 20 mm). The model was used to test two different belt materials with various contamination types, such as biofilms formed by bacteria in carbohydrate- or protein-fat-based soils, dried microorganisms (bacteria, yeasts, and mold spores), and allergens. Ultrasound treatment increased the reduction of bacteria and yeast by 1 to 2 log CFU under the most favorable conditions compared with water or water-detergent controls. The effect was dependent on the type of belt material, the power applied, the exposure time, and the distance between the probe and the belt coupon. Generally, dried microorganisms were more easily removed than biofilms. The effect on mold spores was variable and appeared to be species and material dependent. Spiked allergens were also efficiently removed by using ultrasound. The results in this study pave the way for new cleaning designs for flat conveyor belts, with possibilities for savings of water, detergent, and energy consumption.

Axelsson L; Holck A; Rud I; Samah D; Tierce P; Favre M; Kure CF

2013-08-01

209

Fluorine uptake into the human tooth from a thin layer of F-releasing material  

International Nuclear Information System (INIS)

Using the proton induced gamma-ray emission (PIGE) method (TIARA, Japan), we have studied fluorine (F) distribution in the human tooth under various conditions. Here, we report F uptake into the human tooth from a thin layer of F-releasing low viscous resin (FLVR). Crowns of human teeth were horizontally cut and the dentin of the cut surface was first covered with four kinds of FLVR (FL-Bond, Reactmer Bond, Xeno Bond, and Protect Liner F; thickness, 50-150 ?m) according to the manufacturers' instructions. Non-F-releasing and F-releasing filling resins were also hardened, on the cut surfaces of crowns covered with four kinds of FLVR thin layers. The type of the non-F-releasing filling materials used was LITE FIL IIP: G1-A (FL-Bond and LITE FIL IIP), G2-A (Reactmer Bond and LITE FIL IIP), G3-A (Xeno Bond and LITE FIL IIP), and G4-A (Protect Liner F and LITE FIL IIP). The types of F-releasing filling materials used were G1-B (FL-Bond and Beautifil), G2-B (Reactmer Bond and Reactmer Paste), G3-B (Xeno Bond and Xeno CF Paste), and G4-B (Protect Liner F and Teethmate F-1). Treatment and measurements of specimens were the same as previously reported [H. Yamamoto, M. Nomahci, K. Yasuda, Y. Iwami, S. Ebisu, N. Yamamoto, T. Sakai, T. Kamiya, Nucl. Instr. and Meth. B 210 (2003) 388]. F uptake from specimens following one month of application was estimated from 2-D maps. F penetration was observed in all teeth of G1-A-G4-A groups. The maximum values of F concentration in each tooth and F penetration depth were larger for larger F concentrations in FLVR. FLVR was useful for the F uptake into the tooth, and the F distribution near the thin layer of FLVR depended on the materials used. Between G1-A and G1-B or G4-A and G4-B, the F uptake was significantly different. We were able to obtain fundamental data, which were useful for the analysis of F transportation relating to prevention of caries

2007-01-01

210

Lattice-preferred orientation of lower mantle materials and seismic anisotropy in the D? layer  

Science.gov (United States)

Results of experimental studies and theoretical calculations on deformation of D? layer minerals are reviewed. We conclude that only the results from the experiments under high temperature and modest stress conditions are potentially applicable to the deformation fabrics in the D? layer. For perovskite and post-perovskite, such experimental data are available only for analog materials. By combining those results with elastic properties, we investigate the nature of seismic anisotropy corresponding to a given deformation geometry. Both azimuthal and polarization anisotropies are expected for all minerals. For horizontal flow, perovskite will produce VSV>VSH anisotropy whereas (Mg,Fe)O shows VSH>VSV anisotropy. VSH>VSV anisotropy caused by post-perovskite depends on the elastic anisotropy and the dominant glide plane, both of which are not well constrained. If we choose (010) as a glide plane, weak VSH>VSV or VSV>VSH anisotropy will develop for shear deformation of post-perovskite depending on the elastic constants. For this glide plane, the magnitude of the anisotropy of (Mg,Fe)O is much larger than that for post-perovskite. For a vertical cylindrical flow expected for upwelling mantle plumes, VSV>VSH anisotropy is expected for both (Mg,Fe)O and post-perovskite but not for perovskite. We conclude that (Mg,Fe)O plays a more important role than post-perovskite for the interpretation of seismic anisotropy in both circum Pacific and the central Pacific D? layer. In the circum Pacific regions, the seismic anisotropy can be attributed to the deformation-induced lattice-preferred orientation of (Mg,Fe)O and post-perovskite, whereas some additional contribution from aligned melt pocket might be important in the central Pacific.

Yamazaki, Daisuke; Karato, Shun-ichiro

211

Conceptual material design for magnetic tunneling junction cap layer for high magnetoresistance ratio  

International Nuclear Information System (INIS)

A conceptual material design for magnetic tunneling junction cap layer realizing a steep NiFe/AlOx interface is proposed. Tunnel magneto resistance stack of cap/NiFe/AlOx/CoFe/Ru/CoFe/PtMn/Ta//sub was prepared. Maximum magnetoresistance (MR) ratios of nonmagnetic-NiFeZr, Zr, Ta, Ru, and Rh caps at 0 V were 55%, 28%, 50%, 43%, and 42%, respectively. The decrease of MR ratio and the increase of resistance area product RA with Ru cap compared to Ta cap correlate with the partial oxidation of the NiFe/AlOx interface occurring in additional postannealing, which was confirmed by focused-ion-beam-transmission-electron-microscope-energy-dispersive- x-ray-fluorescence observation. Since standard electrode potential is Ta

2006-04-15

212

Improved description of soft layered materials with van der Waals density functional theory  

International Nuclear Information System (INIS)

The accurate description of van der Waals forces within density functional theory is currently one of the most active areas of research in computational physics and chemistry. Here we report results on the structural and energetic properties of graphite and hexagonal boron nitride, two layered materials where interlayer binding is dominated by van der Waals forces. Results from several density functionals are reported, including the optimized Becke88 van der Waals (optB88-vdW) and the optimized PBE van der Waals (optPBE-vdW) (Klimeš et al 2010 J. Phys.: Condens. Matter 22 022201) functionals. Where comparison to experiment and higher-level theory is possible, the results obtained from the two new van der Waals density functionals are in good agreement. An analysis of the physical nature of the interlayer binding in both graphite and hexagonal boron nitride is also reported.

2012-10-24

213

Non-destructive characterization of surface layers on non ferromagnetic materials  

International Nuclear Information System (INIS)

Electromagnetic nondestructive techniques are usually applied to solve many inspection problems in industry. In particular, eddy currents are used for the detection of defects and the characterization of physical properties of metallic materials and components. One such application is the measurement of thickness of non conductive layers on a conducting substrate. A laboratory device for the quantitative determination of those thicknesses was developed at our laboratory. It works in the range from 0 to 100 ?m and was calibrated with a micro metre screw. This task involved the design and construction of the sensors their characterization (working frequency, resolution, sensitivity, etc.) and the setup of the mechanical system and the electronic signal generation and measurement circuit. (author)

1997-01-01

214

Materials for the active layer of organic photovoltaics: ternary solar cell approach.  

Science.gov (United States)

Power conversion efficiencies in excess of 7% have been achieved with bulk heterojunction (BHJ)-type organic solar cells using two components: p- and n-doped materials. The energy level and absorption profile of the active layer can be tuned by introduction of an additional component. Careful design of the additional component is required to achieve optimal panchromatic absorption, suitable energy-level offset, balanced electron and hole mobility, and good light-harvesting efficiency. This article reviews the recent progress on ternary organic photovoltaic systems, including polymer/small molecule/functional fullerene, polymer/polymer/functional fullerene, small molecule/small molecule/functional fullerene, polymer/functional fullerene I/functional fullerene II, and polymer/quantum dot or metal/functional fullerene systems. PMID:23288712

Chen, Yung-Chung; Hsu, Chih-Yu; Lin, Ryan Yeh-Yung; Ho, Kuo-Chuan; Lin, Jiann T

2013-01-03

215

Water management in a PEMFC: water transport mechanism and material degradation in gas diffusion layers  

Energy Technology Data Exchange (ETDEWEB)

It has now been well recognized that both the performance and durability of proton exchange membrane fuel cells (PEMFCs) are closely related to the water accumulation and transport inside its porous components, particularly in the gas diffusion layer (GDL), and microporous layer (MPL). In this paper, the key GDL and MPL properties that affect water transport through them are first discussed and a review of GDL degradation mechanisms is presented. An intermittent water drainage mechanism across the GDL is discussed. The capillary breakthrough pressure (CBP) and the dynamic capillary pressure (DCP), or recurrent breakthrough dynamics, have been identified as key GDL properties that affect its water management performance and function as indicators of the degradation of GDL material. This work uses a novel ex situ experiment to degrade a GDL by exposing it to an accelerated stress test (AST) that subjects the GDL to elevated operation conditions seen at the cathode side of a PEMFC for an extended period of time. In turn, the effect of the AST on the CBP and DCP is investigated. As a result, a loss of hydrophobicity occurred on the MPL surface. This altered the CBP and DCP, thus decreasing water management in the GDL. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Kandlikar, S.G.; Garofalo, M.L.; Lu, Z. [Department of Mechanical Engineering, Rochester Institute of Technology, 76 Lomb Memorial Drive, Rochester, NY 14623 (United States)

2011-12-15

216

Periodic materials-based vibration attenuation in layered foundations: experimental validation  

Science.gov (United States)

Guided by the recent advances in solid-state research in periodic materials, a new type of layered periodic foundation consisting of concrete and rubber layers is experimentally investigated in this paper. The distinct feature of this new foundation is its frequency band gaps. When the frequency contents of a wave fall within the range of the frequency band gaps, the wave, and hence its energy, will be weakened or cannot propagate through the foundation, so the foundation itself can serve as a vibration isolator. Using the theory of elastodynamics and the Bloch-Floquet theorem, the mechanism of band gaps in periodic composites is presented, and a finite element model is built to show the isolation characteristic of a finite dimensional periodic foundation. Based on these analytical results, moreover, a scaled model frame and a periodic foundation were fabricated and shake table tests of the frame on the periodic foundation were performed. Ambient, strong and harmonic vibration attenuations are found when the exciting frequencies fall into the band gaps.

Xiang, H. J.; Shi, Z. F.; Wang, S. J.; Mo, Y. L.

2012-11-01

217

The thin electrolyte layer approach to corrosion testing of dental materials--characterization of the technique.  

Science.gov (United States)

An innovative technique for corrosion testing of metallic dental materials is introduced. The thin electrolyte layer technique (TET) simulates the physical characteristics of the oral environment by employing a still, thin layer of an electrolyte, in contrast to bulk electrolyte techniques (BET) which utilize relatively large quantities of fluid. Limiting current density tests on a platinum electrode revealed a lower surface oxygen content for TET. Borate buffer (pH 6.8) was employed as an electrolyte. The effect of lower oxygen content in TET on passivation and polarization characteristics of 316L SS in 0.9% saline was investigated. The results revealed differences in the polarization resistance and open circuit potential development with time, as well as in anodic and cathodic polarization behavior. Lower O2 concentration in TET was attributed to different electrolyte convection characteristics under both testing conditions. Additionally, use of the TET resulted in better data reproducibility. Overall, this investigation led to a deeper understanding of the electrochemical processes inherent in thin electrolytes such as those found in the oral environment. PMID:9884061

Ledvina, M; Rigney, E D

1998-12-01

218

The thin electrolyte layer approach to corrosion testing of dental materials--characterization of the technique.  

UK PubMed Central (United Kingdom)

An innovative technique for corrosion testing of metallic dental materials is introduced. The thin electrolyte layer technique (TET) simulates the physical characteristics of the oral environment by employing a still, thin layer of an electrolyte, in contrast to bulk electrolyte techniques (BET) which utilize relatively large quantities of fluid. Limiting current density tests on a platinum electrode revealed a lower surface oxygen content for TET. Borate buffer (pH 6.8) was employed as an electrolyte. The effect of lower oxygen content in TET on passivation and polarization characteristics of 316L SS in 0.9% saline was investigated. The results revealed differences in the polarization resistance and open circuit potential development with time, as well as in anodic and cathodic polarization behavior. Lower O2 concentration in TET was attributed to different electrolyte convection characteristics under both testing conditions. Additionally, use of the TET resulted in better data reproducibility. Overall, this investigation led to a deeper understanding of the electrochemical processes inherent in thin electrolytes such as those found in the oral environment.

Ledvina M; Rigney ED

1998-12-01

219

Development of nano cerium oxide incorporated aluminium alloy sacrificial anode for marine applications  

International Nuclear Information System (INIS)

Aluminium-zinc alloy sacrificial anodes are extensively used for cathodic protection. The performance of the sacrificial anodes can be significantly improved by incorporation of microalloying elements in the aluminium matrix. In the present work nano cerium oxide particles of different concentrations, ranging from 0 to 1 wt% were incorporated for activating and improving the performance of the anode. The electrochemical test results revealed the increased efficiency of the anode. The electrochemical impedance spectroscopy revealed the information that the presence of nano cerium oxide in the anode matrix caused effective destruction of the passive alumina film, which facilitated enhancement of galvanic performance of the anode. Moreover, the biocidal activity of cerium oxide prevented the bio accumulation considerably which enables the anodes to be used in aggressive marine conditions.

2008-01-01

220

Sacrificial cathodic protection of a concrete overpass using metallized zinc: Latest update  

Energy Technology Data Exchange (ETDEWEB)

Removal of the salt-contaminated concrete, patching and the application of waterproofing membranes are some of the possible treatments that, alone or in combination, have been traditionally used to rehabilitate corrosion-damaged infrastructure. However, there are concerns about the effectiveness of only using such approach to mitigate reinforcement corrosion when the concrete is salt contaminated. Sacrificial cathodic protection using metallized zinc coatings is regarded by many as a possible rehabilitation alternative. In order to investigate it, seven reinforced concrete columns of a bridge in Montreal have been flame sprayed with zinc. The zinc anode has delivered adequate levels of cathodic protection for more than 24 months. Although initially the sacrificial current provided by the metallized zinc decreased, it now appears to have stabilized to an acceptable level.

Brousseau, R.; Baldock, B.; Pye, G.; Gu, P. [National Research Council of Canada, Ottawa, Ontario (Canada). Inst. for Research in Construction

1997-12-01

 
 
 
 
221

The effect of grain size on the efficiency of indium-activated, aluminum alloy sacrificial anodes  

Energy Technology Data Exchange (ETDEWEB)

Metallurgical features in as-cast, aluminum alloy, sacrificial anodes, such as the casting grain size, have been found to vary somewhat dramatically in recent procurements from different vendors. There appears to be a linkage between the casting grain size and the electrochemical performance efficiency. This study documents the physical metallurgy features and electrochemical performance of castings prepared by several techniques over a range of temperatures, and includes information regarding casting cooling rates and heat treatments for grain growth.

Murray, J.N.; Kohler, L.K.

1999-07-01

222

The use of a sacrificial zinc anode for cathodic protection of steel in reinforced concrete  

Energy Technology Data Exchange (ETDEWEB)

The problem of corrosion of the reinforcing steel in concrete is recognized as a worldwide problem. In particular, these is extensive corrosion in residential and commercial balconies in tropical, coastal areas of the US, especially in Florida. A system of cathodic protection of reinforcing steel in concrete utilizing a sacrificial zinc anode and ionically conductive adhesive is described. Installation and monitoring of two condominium balconies in south Florida will be described, including instant-off and depolarization measurements over 18 months.

Hartman, R.B.; Hillier, W.H. [3M Co., St. Paul, MN (United States)

1997-12-01

223

Spinel-layered core-shell cathode materials for Li-ion batteries  

Energy Technology Data Exchange (ETDEWEB)

In an attempt to overcome the problems associated with LiNiO{sub 2}, the solid solution series of lithium nickel-metal oxides, Li[Ni{sub 1-x}M{sub x}]O{sub 2} (with M = Co, Mn, Al, Ti, Mg, etc.), have been investigated as favorable cathode materials for high-energy and high-power lithium-ion batteries. However, along with the improvement in the electrochemical properties in Ni-based cathode materials, the thermal stability has been a great concern, and thus violent reaction of the cathode with the electrolyte needs to be avoided. Here, we report a heterostructured Li[Ni{sub 0.54}Co{sub 0.12}Mn{sub 0.34}]O{sub 2} cathode material which possesses both high energy and safety. The core of the particle is Li[Ni{sub 0.54}Co{sub 0.12}Mn{sub 0.34}]O{sub 2} with a layered phase (R3-m) and the shell, with a thickness of < 0.5 {mu}m, is a highly stable Li{sub 1+x}[CoNi{sub x}Mn{sub 2-x}]{sub 2}O{sub 4} spinel phase (Fd-3m). The material demonstrates reversible capacity of 200 mAhg-1 and retains 95% capacity retention under the most severe test condition of 60 C. In addition, the amount of oxygen evolution from the lattice in the cathode with two heterostructures is reduced by 70%, compared to the reference sample. All these results suggest that the bulk Li[Ni{sub 0.54}Co{sub 0.12}Mn{sub 0.34}]O{sub 2} consisting of two heterostructures satisfy the requirements for hybrid electric vehicles, power tools, and mobile electronics. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Cho, Yonghyun; Lee, Sanghan; Lee, Yongseok; Cho, Jaephil [Converging Research Center for Innovative Battery Technologies and Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Hong, Taeeun [Busan Centre, Korea Basic Science Institute (KBSI), Gangseo, Busan, 618-230 (Korea, Republic of)

2011-10-15

224

Improvement of the oxidation resistance of a graphite material by compositionally gradient SiC/C layer  

International Nuclear Information System (INIS)

For the improvement of the oxidation resistance of a graphite material, a preparation study of compositionally gradient SiC/C layer was performed. The compositionally gradient material of SiC/C, which is a graphite material with compositionally gradient SiC/C layer, was produced by a combination of the reaction between gaseous SiO and graphite and chemical vapour deposited SiC coating. The compositionally gradient material showed the same excellent oxidation resistance as the SiC coated graphite material at high temperatures in air. Against severe thermal cycle, furthermore, the compositionally gradient material exhibited more stable characteristic compared with the SiC coated graphite. (orig.).

1993-01-01

225

Effect of Alclad Layer on Material Flow and Defect Formation in Friction-Stir-Welded 2024 Aluminum Alloy  

Science.gov (United States)

The effect of the Alclad layer on material flow and defect formation during friction-stir welding (FSW) of 6.5-mm-thick 2024Al-T351 alloy plates was investigated. To characterize the material flow during FSW, different cross sections of the keyhole and "stop-action weld" were made for metallographic observations. It was found that the top Alclad assembled at the shoulder/workpiece interface, thereby weakening the material flow in the shoulder-driven zone and favoring the formation of void defect at high traveling speeds. The bottom Alclad layer extended into the weld at excess material flow state, which could be avoided at balanced material flow state. A conceptual model of material flow was proposed to describe the formation of the weld. It was indicated that a perfect FSW joint of Alclad 2024Al alloy without defect could be obtained at an optimum FSW condition.

Zhang, Z.; Xiao, B. L.; Wang, D.; Ma, Z. Y.

2011-06-01

226

Effect of the number of graded layers on the microstructure and properties of SiC/C functionally graded materials  

Energy Technology Data Exchange (ETDEWEB)

SiC/C bulk functionally graded materials (FGMs) with different numbers of graded layers (N) for fusion technology were designed and fabricated successfully by a power stacking method and hot-pressing process under the pressure of 30 MPa at 2000 deg. C. Results showed that the number of graded layers (N) had marked effect on the microstructure and properties of the as-received SiC/C FGMs. SEM examinations indicated that interfaces between the adjacent layers faded out gradually and became more linearly continuous gradient with increasing number of graded layers, which led to marked improvement in the bend strength and thermal shock resistance of the samples. Water quenching tests with a temperature difference of 500 deg. C showed that SiC/C FGMs with N > 8 had the best thermal shock resistance for the materials studies, and no cracks occurred after 90 quench cycles.

Zhang, Guobing [Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, PR China (China); Graduate school, Chinese Academy of Sciences, Beijing 100039, PR China (China); Guo, Quangui [Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, PR China (China); Li, Xiutao; Zhang, Hua [Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, PR China (China); Graduate school, Chinese Academy of Sciences, Beijing 100039, PR China (China); Song, Yan; Shi, Jingli [Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, PR China (China); Liu, Lang [Key Laboratory of Carbon Materials, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, Shanxi 030001, PR China (China)], E-mail: zhanggb0929@yahoo.com.cn

2007-06-15

227

Effect of the number of graded layers on the microstructure and properties of SiC/C functionally graded materials  

International Nuclear Information System (INIS)

SiC/C bulk functionally graded materials (FGMs) with different numbers of graded layers (N) for fusion technology were designed and fabricated successfully by a power stacking method and hot-pressing process under the pressure of 30 MPa at 2000 deg. C. Results showed that the number of graded layers (N) had marked effect on the microstructure and properties of the as-received SiC/C FGMs. SEM examinations indicated that interfaces between the adjacent layers faded out gradually and became more linearly continuous gradient with increasing number of graded layers, which led to marked improvement in the bend strength and thermal shock resistance of the samples. Water quenching tests with a temperature difference of 500 deg. C showed that SiC/C FGMs with N > 8 had the best thermal shock resistance for the materials studies, and no cracks occurred after 90 quench cycles.

2007-01-01

228

Multiple layers of self-asssembled Ge/Si islands: Photoluminescence, strain fields, material interdiffusion, and island formation  

International Nuclear Information System (INIS)

Strain fields in stacked layers of vertically aligned self-assembled Ge islands on Si(100) can cause a reduction of the wetting layer thickness in all but the initial layer and hence induce an energy separation ?Ewl between the energy transitions of the different wetting layers. Our systematic photoluminescence (PL) study on twofold stacked Ge/Si layers shows that the quantity ?Ewl is a sensitive function of the Si spacer thickness and reflects the degree of strain field interaction between the island layers. Pronounced PL blueshifts are also observed for the island related energy transition in twofold and multifold island layers. We suggest that with increasing number of stacked island layers strain field superposition of buried islands causes enhanced SiGe material intermixing during Si overgrowth of the islands. This effect naturally explains the strong PL blueshift of the island related energy transition. Recently observed shape transformations in stacked Ge islands are well explained by our model of superimposed strain fields. We also discuss the initial stages of island formation in the second Ge layer of twofold island stacks. Many of the effects observed in this paper on the Ge/Si system are probably also important for self-assembling III/V islands but due to extremely small sizes are much harder to evaluate.

2000-05-15

229

Multilayer sheet material for protective clothing, especially for firemen, has a double external layer which shrinks when exposed to heat, with pockets between layers formed by linking selected threads  

UK PubMed Central (United Kingdom)

Multilayer sheet material for fireproof protective clothing has a double external layer comprising a layer which undergoes shrinkage when exposed to heat, with interlayer pockets formed by intermittently linking selected threads in the two layers. Complex multilayer sheet material for protective clothing, especially for fire fighters, with an external fabric/thermal barrier comprising first and second layers, is made by weaving or knitting so as to form a double-faced, superimposed structure (1, 2) bound together intermittently to form pockets, with one layer showing shrinkage when heated and the connection between the layers being formed by intermittent linkage of a selection of threads to form these pockets.

THIRIOT LAURENT

230

Biofabrication of multi-material anatomically shaped tissue constructs.  

Science.gov (United States)

Additive manufacturing in the field of regenerative medicine aims to fabricate organized tissue-equivalents. However, the control over shape and composition of biofabricated constructs is still a challenge and needs to be improved. The current research aims to improve shape, by converging a number of biocompatible, quality construction materials into a single three-dimensional fiber deposition process. To demonstrate this, several models of complex anatomically shaped constructs were fabricated by combined deposition of poly(vinyl alcohol), poly(?-caprolactone), gelatin methacrylamide/gellan gum and alginate hydrogel. Sacrificial components were co-deposited as temporary support for overhang geometries and were removed after fabrication by immersion in aqueous solutions. Embedding of chondrocytes in the gelatin methacrylamide/gellan component demonstrated that the fabrication and the sacrificing procedure did not affect cell viability. Further, it was shown that anatomically shaped constructs can be successfully fabricated, yielding advanced porous thermoplastic polymer scaffolds, layered porous hydrogel constructs, as well as reinforced cell-laden hydrogel structures. In conclusion, anatomically shaped tissue constructs of clinically relevant sizes can be generated when employing multiple building and sacrificial materials in a single biofabrication session. The current techniques offer improved control over both internal and external construct architecture underscoring its potential to generate customized implants for human tissue regeneration. PMID:23817739

Visser, Jetze; Peters, Benjamin; Burger, Thijs J; Boomstra, Jelle; Dhert, Wouter J A; Melchels, Ferry P W; Malda, Jos

2013-07-02

231

Biofabrication of multi-material anatomically shaped tissue constructs  

International Nuclear Information System (INIS)

[en] Additive manufacturing in the field of regenerative medicine aims to fabricate organized tissue-equivalents. However, the control over shape and composition of biofabricated constructs is still a challenge and needs to be improved. The current research aims to improve shape, by converging a number of biocompatible, quality construction materials into a single three-dimensional fiber deposition process. To demonstrate this, several models of complex anatomically shaped constructs were fabricated by combined deposition of poly(vinyl alcohol), poly(?-caprolactone), gelatin methacrylamide/gellan gum and alginate hydrogel. Sacrificial components were co-deposited as temporary support for overhang geometries and were removed after fabrication by immersion in aqueous solutions. Embedding of chondrocytes in the gelatin methacrylamide/gellan component demonstrated that the fabrication and the sacrificing procedure did not affect cell viability. Further, it was shown that anatomically shaped constructs can be successfully fabricated, yielding advanced porous thermoplastic polymer scaffolds, layered porous hydrogel constructs, as well as reinforced cell-laden hydrogel structures. In conclusion, anatomically shaped tissue constructs of clinically relevant sizes can be generated when employing multiple building and sacrificial materials in a single biofabrication session. The current techniques offer improved control over both internal and external construct architecture underscoring its potential to generate customized implants for human tissue regeneration. (paper)

2013-01-01

232

Changes in the structure of the surface layer of metal materials upon friction and electric current loading  

Science.gov (United States)

Dependences of the electric conductivity of a contact and wear intensity of metal materials on the electric current density in sliding friction are obtained. It is established that alloying of the material basis leads to faster damage of the friction surface. The presence of about 40 ?t.% oxygen in the surface layer is detected by the Auger spectrometry method. It is demonstrated by the x-ray diffraction method that FeO formed in the surface layer leads to an increase in the electric conductivity of the contact.

Fadin, V. V.

2013-09-01

233

Novel approach to material evaluation of thin surface layers by resonant ultrasound spectroscopy  

Energy Technology Data Exchange (ETDEWEB)

The laser-based modal resonant ultrasound spectroscopy is modified for measurements of thin surface layers on a substrate. This paper describes determination of all in-plane elastic properties of thin layers from small resonant frequency shifts of substrate induced by deposition of the layer.

Landa, Michal; Ruzek, Michal; Sedlak, Petr; Seiner, Hanus; Bodnarova, Lucie; ZIdek, Jan, E-mail: ml@it.cas.c [Institute of Thermomechanics, ASCR, v.v.i., Dolejskova 5, 18200 Prague 8 (Czech Republic)

2010-03-01

234

Novel approach to material evaluation of thin surface layers by resonant ultrasound spectroscopy  

International Nuclear Information System (INIS)

[en] The laser-based modal resonant ultrasound spectroscopy is modified for measurements of thin surface layers on a substrate. This paper describes determination of all in-plane elastic properties of thin layers from small resonant frequency shifts of substrate induced by deposition of the layer.

2010-03-01

235

Electroluminescence and impedance analyses of organic light emitting diodes using anhydride materials as cathode interfacial layers  

International Nuclear Information System (INIS)

Pyromellitic dianhydride (PMDA) and trimellitic anhydride (TMA) were tried as cathode interfacial layers between tris-(8-hydroxyquinoline) aluminum (Alq3) and Al in organic light emitting diodes (OLEDs). Both ultra-thin anhydride cathode interfacial layers improved the electroluminescence characteristics of OLEDs compared to those without any interfacial layer, and the PMDA interfacial layer showed the most significant enhancement of the device performance. According to impedance measurements and equivalent circuit analysis, the PMDA interfacial layer decreased the impedance, probably due to the increase in the injection efficiency of electrons from the Al cathode.

2009-05-29

236

Energy loss spectrum of swift charged particles penetrating a layer of material  

International Nuclear Information System (INIS)

[en] The energy loss spectrum of a beam of charged particles penetrating a layer of random material has been analyzed theoretically. A steepest-descent evaluation of the Bothe-Landau integral yields general expressions for the spectrum, the most probable energy loss, and the halfwidth, without reference to a particular collision cross section. The procedure has been tested against rigorous results for model cross sections as well as the Landau-Vavilov theory for free-Coulomb scattering. The most probable energy loss is found to be systematically smaller than the mean energy loss by an amount which is independent of foil thickness for not-too-thin foils. This peak shift turns out to be insensitive to the angle of emergence from the foil but sensitive to nonuniformities in foil thickness and to detector resolution. The influence of shell corrections on the spectrum has been discussed, and the peak shift has been evaluated explicitly for the Landau-Vavilov case, for moderately relativistic ions, for slow ions stopped in a free electron gas, and for heavy ions stopped by elastic collisions. A procedure has been outlined for determining stopping power and straggling from measured peak energy losses and halfwidths. Systematic errors may be present in current stopping power data, caused by the use of most probable instead of mean energy loss values. Estimated peak shifts compare well with recent experimental results. (orig.)

1985-01-01

237

A sodium layered manganese oxides as 3 V cathode materials for secondary lithium batteries  

International Nuclear Information System (INIS)

The synthesis of a new anhydrous sodium manganese oxide ?-Na0.66MnO2.13 obtained via a sol-gel process in organic medium is reported. The partial and limited removal of sodium ions from the layered host lattice (hexagonal symmetry; a = 2.84 A, c = 11.09 A) allows to get a high and stable specific capacity of 180 mAh g-1 at C/20 in the cycling limits 4.3/2 V with a mean working voltage of 3 V without the emergence of a spinel phase. By introducing acetylene black in solution during the sol-gel reaction, a composite material containing 8 wt.% AB has been obtained. The rate capability is shown to be significantly improved leading to an increase of the available specific capacity with for instance 200 and 90 mAh g-1 at C/20 and C rate. This effect is ascribed to a better electronic contact between particles and/or the modification of the oxide surface which makes the intercalation process more homogeneous and more efficient.

2006-10-25

238

Refractory nanoporous materials fabricated using tungsten atomic layer deposition on silica aerogels  

Science.gov (United States)

We report an approach for preparing refractory nanoporous materials using high surface area silica aerogels as templates for the growth of conformal tungsten (W) coatings by atomic layer deposition (ALD). Nanoporous silica aerogel monoliths were prepared with a variety of initial pore sizes and initial densities in the range of 0.3-0.5 g/cc using porogen extraction methods. Next, W ALD using Si2H6 and WF6 reactants at 200 °C was employed to coat the inner surfaces of the silica aerogels. After coating, scanning electron microscopy revealed a microstructure in which the ALD W completely encapsulated the silica aerogel micro-cells. The porosity of the aerogels was preserved during the first 10 W ALD cycles allowing the density to be controlled by adjusting the number of W ALD cycles to achieve densities as high as 5 g/cc. Nitrogen adsorption surface area measurements revealed a gradual decrease in the surface area of the silica aerogels with increasing numbers of W ALD cycles, consistent with a partial filling of the aerogel voids. The high density nanoporous tungsten monoliths survived high temperature vacuum heating (1500 °C) making them promising candidates for solid rare-isotope catchers that can be used in the production of short-lived radioactive isotope beams in facilities such as the facility for rare isotope beams (FRIB).

Mane, Anil U.; Greene, John P.; Nolen, Jerry A.; Sampathkumaran, Uma; Owen, Thomas W.; Winter, Ray; Elam, Jeffrey W.

2012-06-01

239

Multiple pass and multiple layer friction stir welding and material enhancement processes  

Energy Technology Data Exchange (ETDEWEB)

Processes for friction stir welding, typically for comparatively thick plate materials using multiple passes and multiple layers of a friction stir welding tool. In some embodiments a first portion of a fabrication preform and a second portion of the fabrication preform are placed adjacent to each other to form a joint, and there may be a groove adjacent the joint. The joint is welded and then, where a groove exists, a filler may be disposed in the groove, and the seams between the filler and the first and second portions of the fabrication preform may be friction stir welded. In some embodiments two portions of a fabrication preform are abutted to form a joint, where the joint may, for example, be a lap joint, a bevel joint or a butt joint. In some embodiments a plurality of passes of a friction stir welding tool may be used, with some passes welding from one side of a fabrication preform and other passes welding from the other side of the fabrication preform.

Feng, Zhili (Knoxville, TN); David, Stan A. (Knoxville, TN); Frederick, David Alan (Harriman, TN)

2010-07-27

240

Preparation and biological evaluation of a fibroblast growth factor-2-apatite composite layer on polymeric material.  

UK PubMed Central (United Kingdom)

A polymeric percutaneous device with good biocompatibility and resistance to bacterial infection is required clinically. In this study, a fibroblast growth factor-2 (FGF-2)-hydroxyapatite (HAp) composite layer (FHAp layer) was formed on the surfaces of ethylene-vinyl alcohol copolymer (EVOH) specimens using a coating process in a supersaturated calcium phosphate solution supplemented with FGF-2. FGF-2 in the FHAp layer retained its biological activity to promote proliferation of fibroblasts. The EVOH specimens coated with HAp and FHAp layers were percutaneously implanted in the scalp of rats. Not only the HAp layer but also the FHAp layer showed good biocompatibility, and FGF-2 showed no harmful effects on the skin tissue responses to the implanted specimen as long as 14 d. No significantly higher infection resistance was verified for the FHAp layer over the HAp layer, although an FHAp layer coated on a metallic percutaneous device for bone fixation demonstrated higher resistance to bacterial infection over an HAp layer in the previous study. The efficacy of FHAp layers coated on percutaneous implants in resistance to bacterial infection depends on physical factors including fixation condition, stiffness and movement of implants.

Sasaki K; Oyane A; Hyodo K; Ito A; Sogo Y; Kamitakahara M; Ioku K

2010-12-01

 
 
 
 
241

Preparation and biological evaluation of a fibroblast growth factor-2-apatite composite layer on polymeric material  

Energy Technology Data Exchange (ETDEWEB)

A polymeric percutaneous device with good biocompatibility and resistance to bacterial infection is required clinically. In this study, a fibroblast growth factor-2 (FGF-2)-hydroxyapatite (HAp) composite layer (FHAp layer) was formed on the surfaces of ethylene-vinyl alcohol copolymer (EVOH) specimens using a coating process in a supersaturated calcium phosphate solution supplemented with FGF-2. FGF-2 in the FHAp layer retained its biological activity to promote proliferation of fibroblasts. The EVOH specimens coated with HAp and FHAp layers were percutaneously implanted in the scalp of rats. Not only the HAp layer but also the FHAp layer showed good biocompatibility, and FGF-2 showed no harmful effects on the skin tissue responses to the implanted specimen as long as 14 d. No significantly higher infection resistance was verified for the FHAp layer over the HAp layer, although an FHAp layer coated on a metallic percutaneous device for bone fixation demonstrated higher resistance to bacterial infection over an HAp layer in the previous study. The efficacy of FHAp layers coated on percutaneous implants in resistance to bacterial infection depends on physical factors including fixation condition, stiffness and movement of implants.

Sasaki, Kenkichi; Kamitakahara, Masanobu; Ioku, Koji [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Oyane, Ayako [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 4, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8562 (Japan); Hyodo, Koji [Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564 (Japan); Ito, Atsuo; Sogo, Yu, E-mail: a-oyane@aist.go.j [Human Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8566 (Japan)

2010-12-15

242

Preparation and biological evaluation of a fibroblast growth factor-2-apatite composite layer on polymeric material.  

Science.gov (United States)

A polymeric percutaneous device with good biocompatibility and resistance to bacterial infection is required clinically. In this study, a fibroblast growth factor-2 (FGF-2)-hydroxyapatite (HAp) composite layer (FHAp layer) was formed on the surfaces of ethylene-vinyl alcohol copolymer (EVOH) specimens using a coating process in a supersaturated calcium phosphate solution supplemented with FGF-2. FGF-2 in the FHAp layer retained its biological activity to promote proliferation of fibroblasts. The EVOH specimens coated with HAp and FHAp layers were percutaneously implanted in the scalp of rats. Not only the HAp layer but also the FHAp layer showed good biocompatibility, and FGF-2 showed no harmful effects on the skin tissue responses to the implanted specimen as long as 14 d. No significantly higher infection resistance was verified for the FHAp layer over the HAp layer, although an FHAp layer coated on a metallic percutaneous device for bone fixation demonstrated higher resistance to bacterial infection over an HAp layer in the previous study. The efficacy of FHAp layers coated on percutaneous implants in resistance to bacterial infection depends on physical factors including fixation condition, stiffness and movement of implants. PMID:20966534

Sasaki, Kenkichi; Oyane, Ayako; Hyodo, Koji; Ito, Atsuo; Sogo, Yu; Kamitakahara, Masanobu; Ioku, Koji

2010-10-22

243

Simulation of trapping properties of high {kappa} material as the charge storage layer for flash memory application  

Energy Technology Data Exchange (ETDEWEB)

We investigated the trapping properties of high {kappa} material as the charge storage layer in non-volatile flash memory devices using a two-dimensional device simulator, Medici. The high {kappa} material is sandwiched between two silicon oxide layers, resulting in the Silicon-Oxide-High {kappa}-Oxide-Silicon (SOHOS) structure. The trap energy levels of the bulk electron traps in high {kappa} material were determined. The programming and erasing voltage and time using Fowler Nordheim tunneling were estimated by simulation. The effect of deep level traps on erasing was investigated. Also, the effect of bulk traps density, thickness of block oxide and thickness of high {kappa} material on the threshold voltage of the device was simulated.

Yeo, Yee Ngee [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Wang Yingqian [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Samanta, Santanu Kumar [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Yoo, Won Jong [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)]. E-mail: eleyoowj@nus.edu.sg; Samudra, Ganesh [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Gao, Dongyue [Silicon Nano Device Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Chong, Chee Ching [Institute of High Performance Computing, 1 Science Park Rd. Singapore Science Park II, Singapore 117528 (Singapore)

2006-05-10

244

Between cannibals. The sacrificial structure of subjectivity devices / Entre caníbales. La estructura sacrificial de los dispositivos de subjetividad  

Directory of Open Access Journals (Sweden)

Full Text Available In the context of current discussions about biopolitics, Roberto Esposito and Jacques Derrida reintroduce the old question of subjectivity to show that any identification always involves some sacrifice. The statement of the cogito, while determining and requiring sacrifice, also reflects it because predator subjectivity is expressed through cannibal rhetoric. The concrete and material sacrifice of those lives that the ego subjugates to assert itself and survive, necessarily depends on another sacrifice, symbolic, but no less violent. The main purpose of these pages is to indicate how Esposito and Derrida articulate a number of categories to explain that the very existence, as a political concept, is an index and a factor of a domain that founds its more precise formulation in the metonymy of eating and its privileged victim in the figure of the animal.////En el contexto de los debates actuales acerca de la biopolítica, Roberto Esposito y Jacques Derrida retoman la vieja cuestión de la subjetividad para mostrar que toda identificación implica siempre un cierto sacrificio. El régimen de enunciación del cogito, al mismo tiempo que determina y exige el sacrificio, lo refleja porque la subjetividad predadora se expresa a través de una retórica caníbal. El sacrificio concreto y material de aquellas vidas que el sujeto somete para poder afirmarse y subsistir depende necesariamente de otro sacrificio, de carácter simbólico, pero no por eso menos violento. El objetivo principal de estas páginas consiste en indicar el modo en que Esposito y Derrida articulan una serie de categorías con el fin de explicitar que la existencia misma, como concepto político, es índice y factor de un dominio que encuentra su formulación más precisa en la metonimia del comer y su víctima privilegiada en la figura del y de lo animal.

Evelyn Galiazo

2011-01-01

245

Hybrid magnetic/superconducting materials obtained by insertion of a single-molecule magnet into TaS2 layers  

International Nuclear Information System (INIS)

[en] A material in which superconducting and magnetic properties coexist is synthesized by the intercalation of single-molecule magnets into the layered structure of a group V metal dichalcogenide. A molecule-based/solid-state hybrid strategy is here employed, proving as a promising chemical approach for preparing new materials in which superconductivity coexists with different molecule-intrinsic functionalities. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

2011-11-16

246

Development of electrodeposited ZnTe layers as window materials in ZnTe/CdTe/CdHgTe multi-layer solar cells  

International Nuclear Information System (INIS)

[en] Zinc telluride (ZnTe) thin films have been deposited on glass/conducting glass substrates using a low-cost electrodeposition method. The resulting films have been characterized using various techniques in order to optimize growth parameters. X-ray diffraction (XRD) has been used to identify the phases present in the films. Photoelectrochemical (PEC) cell and optical absorption measurements have been performed to determine the electrical conductivity type, and the bandgap of the layers, respectively. It has been confirmed by XRD measurement that the deposited layers mainly consist of ZnTe phases. The PEC measurements indicate that the ZnTe layers are p-type in electrical conduction and optical absorption measurements show that their bandgap is in the range 2.10-2.20 eV. p-Type ZnTe window materials have been used in CdTe based solar cell structures, following new designs of graded bandgap multi-layer solar cells. The structures of FTO/ZnTe/CdTe/metal and FTO/ZnTe/CdTe/CdHgTe/metal have been investigated. The results are presented in this paper using observed experimental data

2009-01-01

247

Thermal stress in a bi-material assembly with a 'piecewise-continuous' bonding layer: theorem of three axial forces  

International Nuclear Information System (INIS)

[en] We consider a bi-material assembly with a 'piecewise-continuous' bonding layer. The layer is characterized by different elastic constants of its 'pieces' (segments) and is assumed to be thin. Young's moduli of all the 'pieces' of the bonding layer are significantly lower than the moduli of the adherend materials. In such a situation the coefficient of thermal expansion (CTE) of the bonding material need not be accounted for. Only the interfacial compliance of the bonding layer is important. This is indeed the case for the majority of electronic, opto-electronic or photonic assemblies. We consider the situation when the assembly is manufactured at an elevated temperature and is subsequently cooled down to a low (say, room) temperature. The objective of the analysis is to develop a simple, easy-to-use and physically meaningful analytical ('mathematical') predictive model for the evaluation of the interfacial shearing stresses that arise at the boundaries of the 'pieces' (segments) of the bonding layer and at the assembly edge. The basic equation is obtained for the thermally induced forces acting in the adherends' cross-sections that correspond to the boundaries between the dissimilar portions of the bonding layer. This equation has the form of the theorem of three (bending) moments in the theory of multi-span beams lying on separate simple supports and could therefore be called the 'theorem of three axial forces'. We show, as an illustration, how this equation could be employed to design a bi-material assembly with an inhomogeneous bonding layer and with low interfacial shearing stresses. Low shearing stresses will certainly result in lower peeling stresses as well. The numerical example is carried out for an assembly with a relatively high-modulus bonding material in its mid-portion (aimed primarily at providing good adhesion and, if necessary, good heat transfer as well) and a low-modulus material in its peripheral portions (aimed primarily at bringing down the interfacial stresses). The maximum interfacial shearing stress in the assembly with the inhomogeneous bonding layer turned out to be only about 30% of the maximum shearing stress in an assembly with a homogeneous bonding layer having throughout its length the same modulus as the bonding material in the mid-portion of an assembly with an inhomogeneous bond. We would like to emphasize that the inhomogeneous bonding material addressed in this analysis does not necessarily have to be an epoxy one. Many other bonding materials with different moduli in the mid-portion and at the peripheral portions of the assembly could be considered for various practical applications. For instance, a high-modulus solder material such as, say, a tin-silver-copper (SAC) solder can be employed in the mid-portion of an assembly and a low-modulus solder (e.g. an indium-based alloy) at its peripheral portions. In other applications a high-modulus solder material could be considered for the mid-portion of the assembly and a low-modulus epoxy adhesive at its peripheral portions. We would also like to point out that the developed concept can be easily generalized for the situations when the bonding material is not a continuous one, but is of the ball-grid-array (BGA) or a pad-grid-array (PGA) type. Our concept could also be easily generalized for a two-dimensional case, for the situation when bending deformations should be accounted for, for non-uniform distribution of temperature (i.e. for assemblies with temperature gradients in the through-thickness and/or in the longitudinal direction), for situations when time-dependent effects (visco-elasticity, creep, stress relaxation) in the bonding material are important and for numerous other more complicated and practically important situations that might be encountered in engineering practice.

2009-02-21

248

COMPARATIVE STUDY OF STRESSES AND STRAINS THAT OCCUR IN STRUCTURAL ELEMENTS MADE OF COMPOSITE MATERIALS CONSIDERING THE MODEL WITH AND WITHOUT LAYERS  

Directory of Open Access Journals (Sweden)

Full Text Available Fibreglass-reinforced polyester (GRP) is the most widely used composite material in the ship building industry and requires careful study in point of mechanical characteristics. This article presents the collective experience related to behaviour in different situations of GRP loading. We considered three cases manufacturing for GRP: layers with mechanical characteristics for each layer, composite (the material is considered isotropic but with layers and same mechanical properties for all layers), and isotropic plates.

FLORENTINA TOCU; COSTEL IULIAN MOCANU

2012-01-01

249

Elimination of initial stress-induced curvature in a micromachined bi-material composite-layered cantilever  

Science.gov (United States)

Micro-devices with a bi-material-cantilever (BMC) commonly suffer initial curvature due to the mismatch of residual stress. Traditional corrective methods to reduce the residual stress mismatch generally involve the development of different material deposition recipes. In this paper, a new method for reducing residual stress mismatch in a BMC is proposed based on various previously developed deposition recipes. An initial material film is deposited using two or more developed deposition recipes. This first film is designed to introduce a stepped stress gradient, which is then balanced by overlapping a second material film on the first and using appropriate deposition recipes to form a nearly stress-balanced structure. A theoretical model is proposed based on both the moment balance principle and total equal strain at the interface of two adjacent layers. Experimental results and analytical models suggest that the proposed method is effective in producing multi-layer micro cantilevers that display balanced residual stresses. The method provides a generic solution to the problem of mismatched initial stresses which universally exists in micro-electro-mechanical systems (MEMS) devices based on a BMC. Moreover, the method can be incorporated into a MEMS design automation package for efficient design of various multiple material layer devices from MEMS material library and developed deposition recipes.

Liu, Ruiwen; Jiao, Binbin; Kong, Yanmei; Li, Zhigang; Shang, Haiping; Lu, Dike; Gao, Chaoqun; Chen, Dapeng

2013-09-01

250

A study of Al-Zn-Sn alloy sacrificial anode cathodic protection requirements for structure used in seawater  

International Nuclear Information System (INIS)

Full text: The study will be focused on the alloying of Aluminum alloy sacrificial anode. The work will explore, evaluate and assess the effectiveness of Al-Zn-Sn alloy sacrificial anode tested in tropical seawater. This study is directed toward the development of new and more comprehensive data that will provide a technical basis for improved, more cost - effective guidelines for prediction, verification and optimization of cathodic protection requirements for structures used in tropical seawater. Furthermore, this study will also evaluate the potential and benefits of laboratory research upon marine corrosion without needed to be in the actual marine environment. The influence of alloy composition on the electrochemical properties of this Al-Zn-Sn will be determined by various tasks of testing which fully conducted in the laboratory. SEM and EDAX analysis will be employed in order to characterize surface structure of Al-Zn-Sn alloy. The corrosion measurement analyzer will be used by means to identify the electrochemical properties such as potential, corrosion rate and passivation of Al-Zn-Sn sacrificial anode when immersed in seawater. The relationship between morphological structure and electrochemical results will be examined. The data obtained will be used to evaluate the performance of Al-Zn-Sn alloy as a sacrificial anode cathodic protection for structure used in tropical seawater. Further verification will be made to testify that the Al-Zn-Sn alloy meets the quality requirements to be used as a sacrificial anode in tropical seawater. (author)

2009-07-01

251

Long-term performance of different aluminum alloy designs as sacrificial anodes for rebars  

International Nuclear Information System (INIS)

This paper presents the performance of various cathodic-protection designs using Aluminum alloys to protect prestressed piles. The results obtained with different system designs (bracelete type-Al/Zn/In alloy, thermo sprayed aluminum (3-year evaluation) and conventional Al/Zn/In anodes in an epoxy-painted steel bracelet (12-year evaluation), indicated that all of these systems may be used as sacrificial anodes for pile protection. However, the thermo sprayed aluminum type can not be used in prestressed concrete piles because the very negative potentials (4) they supply to the reinforcement could lead to hydrogen embrittlement. (Author) 16 refs.

2003-01-01

252

Application of thin layer activation technique for surface wear studies in Zr based materials using charged particle induced nuclear reactions  

International Nuclear Information System (INIS)

Thin layer activation (TLA) technique has been developed in Zr based alloy materials, e.g., zircaloy II, using 40 MeV ?-particles from variable energy cyclotron centre at Calcutta. A brief description of the methodology of TLA technique is presented to determine the surface wear. The sensitivity of the measurement of surface wear in zircaloy material is found to be 0.22±0.05 ?m. The surface wear is determined by TLA technique in zircaloy material which is used in pressurised heavy water reactor and the values have been compared with that obtained by conventional technique for the analytical validation of the TLA technique. (orig.)

1998-01-01

253

Impact of seed layer on material quality of epitaxial germanium on silicon deposited by low pressure chemical vapor deposition  

International Nuclear Information System (INIS)

The impact of the growth conditions of the germanium seed layer on the material quality of epitaxial germanium grown on (100) silicon by Low Pressure Chemical Vapor Deposition is studied. In order to obtain a smooth surface morphology, a thin Ge seed layer is grown at low temperature, followed by a thick Ge cap layer at high temperature. An optimal seed deposition condition of 335 deg. C and 4 kPa is identified. Seed layer growth at lower temperatures (e.g. 320 deg. C) leads to the formation of crystallographic defects, while growth above 350 deg. C produces unacceptable surface roughening associated with rapid Ge surface diffusion. Seed growth pressures above 6 kPa are found to lead to gas phase nucleation. A qualitative growth model for the Ge seed layer at 335 deg. C and 4 kPa is also described. It is demonstrated that a Ge seed layer thickness greater than 30 nm is required to obtain smooth Ge films. For seed layers at or below 30 nm thicknesses, the lowered thermal stability of this thin film produces severe islanding during the transition to the cap growth temperature (650 deg. C). In situ doping with boron above ?1019 cm-3 in the seed layer enhances the seed growth rate and lowers the Ge/Si interfacial oxygen level. For in situ annealed 2 ?m-thick Ge films deposited on this seed layer, a threading dislocation density of ?2 x 107 cm-2 is achieved, along with a surface roughness of ?1.6 nm

2006-06-05

254

Electrolytic composite Co-P-TiO{sub 2} layers as electrode materials for oxygen electroevolution  

Energy Technology Data Exchange (ETDEWEB)

Electrolytic composite layers Co-P-TiO{sub 2} were obtained by electrolytic codeposition of cobalt and TiO{sub 2} on a copper substrate from an electrolyte containing a suspension of TiO{sub 2} (100 gdm{sup -3}). The process of electrodeposition was carried out under galvanostatic conditions, in the current density range of 17-40 mAcm{sup -2} with a constant value of electric charge Q=0.12 A h. For comparison, Co-P alloys were also obtained under the same conditions and comparative tests were conducted on them. The phase and chemical composition of layers were determined depending on deposition current density. Electrochemical tests were preceded by electromodification of layers aimed at obtaining an active surface layer. Investigated layers were subjected to a cyclic cathode-anode polarization in the potential range from the value of the hydrogen evolution potential to the value of the oxygen evolution potential for 3 h in 5 M KOH solution. On the surface prepared in such a way the final i-E relation was recorded for each type of layer. After such electrochemical pretreatment, all layers were tested for the process of oxygen evolution in alkaline environment. It was ascertained that incorporation of small amounts of crystalline TiO{sub 2} in the amorphous Co-P matrix improved the rate of oxygen electroevolution on these layers. (orig.) 22 refs.

Surowka, J.; Budniok, A. [Uniwersytet Slaski, Katowice (Poland). Inst. of Physics and Chemistry of Metals; Bzowski, B.; Warczewski, J. [Institute of Physics, University of Silesia ul.Uniwersytecka 4, 40-007 Katowice (Poland)

1997-10-10

255

Fabrication of functionally graded materials between P21 tool steel and Cu by using laser aided layered manufacturing  

Energy Technology Data Exchange (ETDEWEB)

With the development of layered manufacturing, thermally conductive molds or molds embedding conformal cooling channels can be directly fabricated. Although P21 tool steel is widely used as a mold material because of its dimensional stability, it is not efficient for cooling molds owing to its low thermal conductivity. Hence, the use of functionally graded materials (FGMs) between P21 and Cu may circumvent a tradeoff between the strength and the heat transfer rate. As a preliminary study for the layered manufacturing of thermally conductive molds having FGM structures, one dimensional P21 Cu FGMs were fabricated by using laser aided direct metal tooling (DMT), and then, material properties such as the thermal conductivity and specific heat that are related to the heat transfer were measured and analyzed.

Jeong, Jong Seol; Shin, Ki Hoon [Seoul Nat' l Univ., Seoul (Korea, Republic of)

2013-01-15

256

Fabrication of functionally graded materials between P21 tool steel and Cu by using laser aided layered manufacturing  

International Nuclear Information System (INIS)

With the development of layered manufacturing, thermally conductive molds or molds embedding conformal cooling channels can be directly fabricated. Although P21 tool steel is widely used as a mold material because of its dimensional stability, it is not efficient for cooling molds owing to its low thermal conductivity. Hence, the use of functionally graded materials (FGMs) between P21 and Cu may circumvent a tradeoff between the strength and the heat transfer rate. As a preliminary study for the layered manufacturing of thermally conductive molds having FGM structures, one dimensional P21 Cu FGMs were fabricated by using laser aided direct metal tooling (DMT), and then, material properties such as the thermal conductivity and specific heat that are related to the heat transfer were measured and analyzed

2013-01-01

257

Effect of Soft Material Hardness and Hard Material Surface Morphology on Friction and Transfer Layer Formation; Lubricated Condition  

Directory of Open Access Journals (Sweden)

Full Text Available Hot and cold forming of metals is carried out in industry for manufacturing engineering components. Such manufacturing processes employ dies, whose surface condition is one of the factors which characterize the surface finish of engineering components. The surface finish of engineering components is largely influenced by the tribological phenomenon at die and components interface. Lubrication, morphology and hardness of die surface are found to control surface finish of the products. In the present investigation a pin-on-plate sliding tester was used to identify the effect of surface morphology, lubrication and hardness on co-efficient of friction and transfer layer which characterizes the tribological behaviour. The morphology of mild steel (EN8) plate surfaces were modified by employing three different surface modification methods like grinding (silicon carbide wheel polishing), shot blasting and electric discharge machining methods. Surface roughness parameters which characterize the morphology of the steel plates were measured using a three dimensional optical profilometer. Role of hardness is studied by employing lead, copper and Aluminum (Al6082) pins which were slid against steel plates. Experiments were conducted for plate inclination angles of 1, 1.5,2 and 2.5 degrees. Normal load was varied from 1 to 150N during the tests. Experiments were conducted under lubricated condition in ambient environment. Scanning electron microscope was used to study the formation of transfer layer on plate and pin surfaces. It was observed that the co-efficient of friction and transfer layer formation were found to depend on the surface morphology of the harder surface under lubricated condition. The quantum of transfer layer formation on the surfaces is found to increase with increase in surface roughness.

Mr.M Basavaraju; Dr.S Ranganatha

2013-01-01

258

Protein-mediated layer-by-layer synthesis of TiO?(B)/anatase/carbon coating on nickel foam as negative electrode material for lithium-ion battery.  

Science.gov (United States)

Through an aqueous, protein-mediated layer-by-layer titania deposition process, we have fabricated a protamine/titania composite layer on nickel foam. The coating was composed of amorphous carbon and TiO2(B)/anatase nanoparticles and formed upon organic pyrolysis under a reducing atmosphere (5% H2-Ar mixture). X-ray diffraction analyses, Auger electron spectroscopy, and high-resolution transmission electron microscopy revealed that the obtained coatings contained fine monoclinic TiO2(B) and anatase nanocrystals, along with amorphous carbon. Moreover, the coating can be used as a binder-free negative electrode material for lithium-ion batteries and exhibits high reversible capacity and fast charge-discharge properties; a reversible capacity of 245 mAh g(-1) was obtained at a current density of 50 mA g(-1), and capacities of 167 and 143 mAh g(-1) were obtained at current densities of 1 and 2 A g(-1), respectively. PMID:23597025

Wang, Xiaobo; Yan, Yong; Hao, Bo; Chen, Ge

2013-04-18

259

Ab initio and thermodynamic modelling of alloying effects on activity of sacrificial aluminium anodes  

International Nuclear Information System (INIS)

Research highlights: ? Effect of alloying on the corrosion activity of sacrificial Al anodes. ? Sn in solid solution form is a key alloying element for activation of Al anodes. ? Ternary additions that increase Sn solubility decrease the potential of Al alloys. ? Elements bigger than Al expand the Al lattice and allow more Sn to dissolve in Al. ? Large ternary dopants can reduce Sn's solubility in Al if they form compounds with Sn. - Abstract: This work summarizes the experimental literature to date on Al-alloy sacrificial anodes and shows that the presence of Sn as an alloying element in solid solution form consistently debases the alloy corrosion potential. This study then assesses the lattice expander theory, which states that lattice-expanding dopants can be used to increase Sn solubility in Al and thereby reduce passivation. The thermodynamic effects on Sn solubility of lattice expanders (Ga, Mg, Zr, In and Bi) are predicted with ab-initio methods. Our results support lattice expander theory although we demonstrate that Sn solubility can decrease by alloying with even large dopants if they form compounds with Sn.

2011-01-01

260

Magnesium-Based Sacrificial Anode Cathodic Protection Coatings (Mg-Rich Primers) for Aluminum Alloys  

Directory of Open Access Journals (Sweden)

Full Text Available Magnesium is electrochemically the most active metal employed in common structural alloys of iron and aluminum. Mg is widely used as a sacrificial anode to provide cathodic protection of underground and undersea metallic structures, ships, submarines, bridges, decks, aircraft and ground transportation systems. Following the same principle of utilizing Mg characteristics in engineering advantages in a decade-long successful R&D effort, Mg powder is now employed in organic coatings (termed as Mg-rich primers) as a sacrificial anode pigment to protect aerospace grade aluminum alloys against corrosion. Mg-rich primers have performed very well on aluminum alloys when compared against the current chromate standard, but the carcinogenic chromate-based coatings/pretreatments are being widely used by the Department of Defense (DoD) to protect its infrastructure and fleets against corrosion damage. Factors such as reactivity of Mg particles in the coating matrix during exposure to aggressive corrosion environments, interaction of atmospheric gases with Mg particles and the impact of Mg dissolution, increases in pH and hydrogen gas liberation at coating-metal interface, and primer adhesion need to be considered for further development of Mg-rich primer technology.

Shashi S. Pathak; Sharathkumar K. Mendon; Michael D. Blanton; James W. Rawlins

2012-01-01

 
 
 
 
261

Design, materials and R and D issues of innovative thermal contact joints for high heat flux applications  

International Nuclear Information System (INIS)

Plasma facing components in fusion machines are designed with a layer of sacrificial armour material facing the plasma and a high-conductivity material in contact with the coolant. One of the most critical issues associated with making the proposed design concept work, from a power handling point of view, is achieving the necessary contact conductance between the armour and the heat sink.This paper presents a novel idea for the interface joint between the sacrificial armour and the actively cooled permanent heat sink. It consists of a thermal bond layer of a binary or more complex alloy, treated in the semi-solid region in such a way as to lead to a fine dispersion of a globular solid phase into a liquid matrix (rheocast process). The alloy in this ''mushy state'' exhibits a time-dependent, shear rate-dependent viscosity, which is maintained reversibly when the material is solidified and heated again in the semi-solid state. The function of the thermal bond layer is to facilitate heat transfer between the replaceable armour and the permanent heat sink without building up excessive thermal stresses, as in conventional brazed joints, and allow an easy replacement whenever needed without disturbing the coolant system. No contact pressure is required in this case to provide the desired heat transfer conductance, and the reversible thixotropic properties of the rheocast material should guarantee the stability of the layer in the semi-solid conditions.Key design, material and testing issues are identified and discussed in this paper with emphasis on specific needs for future research and development work. Examples of suitable material options which are being considered are reported together with some initial heat transfer analysis results. (orig.).

1994-07-01

262

COMPARISON BETWEEN DISCRETE AND SEMI-CONTINUOUS LAYERED MODELS OF SUPERCONDUCTING VORTICES IN HIGH TC MATERIALS FOR TEM OBSERVATIONS.  

Energy Technology Data Exchange (ETDEWEB)

In order to interpret Transmission Electron Microscopy observations of superconducting vortices in anisotropic or layered materials we have found the analytical solution for the Fourier transform of the electron optical phase shift for the case of a straight vortex piercing the specimen at arbitrary angle. The layered case suffered from the shortcoming that only a limited number of pancakes; up to 7, is allowed by the discrete approach followed. Seven layers, however, are scarcely representative of the real stack of pancake vortices, especially when the core pierces the specimen at large angles with respect to the specimen normal. In fact, in these conditions, the pancake discrete structure may no longer be buried in the diffraction fringes of the Fresnel image. Moreover, a small number of layers is a limiting factor when more exotic vortex structures with no straight cores are investigated. This drawback has been overcome by a semi-continuous approach, where each pancake layer is considered singularly, and the discrete structure of the other pancakes is substituted by a superconducting continuous medium that carries supercurrent only parallel to the layers, as proposed by Clem and further developed by Coffey and Phipps. The solution for the vector potential has been found by Fourier methods, connecting the general solutions in the vacuum with those in the superconducting regions. The presence of a vortex in the layer is taken into account by considering the layer as an additional superconducting region of negligible thickness. Once the vector potential is found, the electron optical phase shift can be calculated by integrating the vector potential along a straight trajectory suitably chosen in order to take correctly into account the overall geometry of the experimental set-up, including a tilt of the specimen with respect to the electron beam.

BELEGGIA,M.; POZZI,G.; TONOMURA,A.

2004-08-01

263

Transient thermal stress analysis of multi-layered composite laminate cylinder and its analytical extension to non-homogeneous materials  

International Nuclear Information System (INIS)

[en] Many kinds of composite materials, which consist of composite structure of matrix material and mixture for reinforcement, have been developed recently. And evaluation or research of their mechanical behaviors have been carried out widely (Vinson et al., 1986). As one of composite materials, metal matrix composites have been developed as new materials which may be adaptable for the super high-temperature environment, and it would be predicted that they show the complicated and characteristic mechanical behaviors, these phenomena could not be shown in isothermal problems due to the external loading. In the present paper, the authors analyze the transient plane thermal stress problem of a multi-layered composite laminated cylinder due to symmetrical and asymmetrical heating. So far as analytical developments for the multi-layered composite cylinder, the authors have introduced the method of Laplace transform to the temperature field and Airy's stress function method to the thermoelastic field, and then evaluated the temperature and thermal stress distributions in a transient state. Moreover, the authors have applied the theoretical developments proposed in this paper into the analysis of a cylinder with nonhomogeneous material properties such as a functionally gradient material

1989-01-01

264

Partially reduced graphite oxide as an electrode material for electrochemical double-layer capacitors.  

UK PubMed Central (United Kingdom)

Partially reduced graphite oxide was prepared from graphite oxide by using synthetic graphite as precursor. The reduction of graphite oxide with a layer distance of 0.57?nm resulted in a reduction of the layer distance depending on the degree of reduction. Simultaneously the amount of oxygen functionalities in the graphite oxide was reduced, which was corroborated by elemental analysis and EDX. The electrochemical activation of the partially reduced graphite oxide was investigated for tetraethylammonium tetrafluoroborate in acetonitrile and in propylene carbonate. The activation potential depends significantly on the degree of reduction, that is, on the graphene-layer distance and on the solvent used. The activation potential decreased with increasing layer distance for both positive and negative activation. The resulting capacitance after activation was found to be affected by the layer distance, the oxygen functionalities and the used electrolyte. For a layer distance of 0.43?nm and with acetonitrile as the solvent, a differential capacitance of 220?Fg(-1) was achieved for the discharge of the positive electrode near the open-circuit potential and 195?Fg(-1) in a symmetric full-cell assembly.

Hantel MM; Kaspar T; Nesper R; Wokaun A; Kötz R

2012-07-01

265

Low-Thermal-Conductivity (MS)1+x(TiS2)2 (M = Pb, Bi, Sn) Misfit Layer Compounds for Bulk Thermoelectric Materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of (MS)1+x(TiS2)2 (M = Pb, Bi, Sn) misfit layer compounds are proposed as bulk thermoelectric materials. They are composed of alternating rock-salt-type MS layers and paired trigonal anti-prismatic TiS2 layers with a van der Waals gap. This naturally modulated structure shows low lattice th...

Chunlei Wan; Yifeng Wang; Ning Wang; Kunihito Koumoto

266

Flaw investigation in a multi-layered, multi-material composite: Using air-coupled ultrasonic resonance imaging  

Science.gov (United States)

Ceramic tiles are the main ingredient of a multi-material, multi-layered composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. Defects in the tile, during manufacture or after usage, are expected to change the resonance frequencies and resonance images of the tile. The comparison of the resonance frequencies and resonance images of a pristine tile/lay-up to a defective tile/lay-up will thus be a quantitative damage metric. By examining the vibrational behavior of these tiles and the composite lay-up with Finite Element Modeling and analytical plate vibration equations, the development of a new Nondestructive Evaluation technique is possible. This study examines the development of the Air-Coupled Ultrasonic Resonance Imaging technique as applied to a hexagonal ceramic tile and a multi-material, multi-layered composite.

Livings, R. A.; Dayal, V.; Barnard, D. J.; Hsu, D. K.

2012-05-01

267

Patterning Technology of Ferrite and Insulating Material in a Single Layer of the Multilayer Ceramic Device  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Patterning technology of ferrite and insulating material in multilayer ceramic devices is proposed. In the conventional technology, the different ceramic materials such as the ferrite and the insulating material have been prepared in the form of the each different green sheet, and then they have bee...

Minami Takato; Aki Kenmochi; Toshiki Fujino; Ken Saito; Fumio Uchikoba

268

Characterization of the Minimum Effective Layer of Thermal Insulation Material Tow-plaster from the Method of Thermal Impedance  

Directory of Open Access Journals (Sweden)

Full Text Available Our objective in this study is to determine the effective thermal insulating layer of a composite towplaster. The characterization of thermal insulating material is proposed from the study of the thermal impedance in dynamic two-dimensional frequency. Thermo physical properties of the material tow-plaster are determined from the study of the thermal impedance. Nyquist representations have introduced an interpretation of certain phenomena of heat transfer from the series and shunt resistors. The overall coefficient of heat exchange is determined from the Bode plots. A method for determining the thermal conductivity is proposed.

M.S. Ould Brahim; I. Diagne, S. Tamba, F. Niang and G. Sissoko

2011-01-01

269

Thin layer chromatography-application in qualitative analysis on presence of coumarins and flavonoids in plant material.  

UK PubMed Central (United Kingdom)

Drugs, natural medicinal plant, animals and mineral materials, have a large and various application in official pharmacy and medicine. Carriers of multilateral pharmacological effects that those drugs shown, are chemically define as active components that are present in them. Methods of qualitative and quantitative analysis are used for the chemical investigation of components that drugs contain. Method of thin layer chromatography has been shown as very reliable. According to the chemical investigation of single drugs, it is possible to define a group of compound or single compound comparing them with standards. Relating to the usage of method of thin layer chromatography, it has been carried out investigation on presence of coumarins and flavonoids in domestic plant material that have wide everyday usage. Coumarins and flavonoids from the point of view of chemical belonging are phenol derivatives with important pharmacological effects. Applying method of thin layer chromatography, it is detected presence of coumarins and flavonoids substances in plant material that has been tested. Anethi graveolens fructus et folium (fruit and leaf of dill), Anethum graveolens L., Apiaceae, Avenae sativae fructus (fruit of oats), Avena sativa L., Poaceae and Asperulae odoratae herba (sweet woodruff), Asperula odorata L., Rubiaceae. Chromatograms are developed in systems cyclohexane-ethylacetat (13:7) and toluene-ether (1:1) saturated with 10% acetic acid, and visualisation by observing on UV lamp (254 and 366 nm), spraying with reagents KOH (10% ethanol solution) and diphenylboryloxyethylamine (1% methanol solution).

Kovac-Besovi? EE; Duri? K

2003-07-01

270

Stacking and registry effects in layered materials: the case of hexagonal boron nitride.  

Science.gov (United States)

The interlayer sliding energy landscape of hexagonal boron nitride (h-BN) is investigated via a van der Waals corrected density functional theory approach. It is found that the main role of the van der Waals forces is to anchor the layers at a fixed distance, whereas the electrostatic forces dictate the optimal stacking mode and the interlayer sliding energy. A nearly free-sliding path is identified, along which band gap modulations of ?0.6??eV are obtained. We propose a simple geometric model that quantifies the registry matching between the layers and captures the essence of the corrugated h-BN interlayer energy landscape. The simplicity of this phenomenological model opens the way to the modeling of complex layered structures, such as carbon and boron nitride nanotubes. PMID:20867872

Marom, Noa; Bernstein, Jonathan; Garel, Jonathan; Tkatchenko, Alexandre; Joselevich, Ernesto; Kronik, Leeor; Hod, Oded

2010-07-19

271

Stacking and registry effects in layered materials: the case of hexagonal boron nitride.  

UK PubMed Central (United Kingdom)

The interlayer sliding energy landscape of hexagonal boron nitride (h-BN) is investigated via a van der Waals corrected density functional theory approach. It is found that the main role of the van der Waals forces is to anchor the layers at a fixed distance, whereas the electrostatic forces dictate the optimal stacking mode and the interlayer sliding energy. A nearly free-sliding path is identified, along which band gap modulations of ?0.6??eV are obtained. We propose a simple geometric model that quantifies the registry matching between the layers and captures the essence of the corrugated h-BN interlayer energy landscape. The simplicity of this phenomenological model opens the way to the modeling of complex layered structures, such as carbon and boron nitride nanotubes.

Marom N; Bernstein J; Garel J; Tkatchenko A; Joselevich E; Kronik L; Hod O

2010-07-01

272

Influence of the type of ceramic moulding materials on the top layer of titanium precision castings  

Directory of Open Access Journals (Sweden)

Full Text Available The article presents the results of the research which was executed to describe the conditions specific of the formation of surface of certain micro-geometry and of the upper layers on precision titanium castings for medical industry. On the ready precision castings some tests were carried out to obtain the surface micro-geometry satisfying the requirements of implants to be used in human organism. The surfaces with specific spherical macro-unevenness were formed as well as plane surfaces of 2 ÷ 6 ?m roughness. With the help of the light and electron microscopy, the possibility of formation of upper layers directly through an interaction of liquid titanium or Ti6Al4V alloy with the first layer of ceramic mould made from the ceramic mixtures based on Ekosil binder and molochite or zirconia has been confirmed.

Myszka D.; Karwi?ski A.; Le?niewski W.; Wieliczko P.

2007-01-01

273

Diffusivity measurements of silicon in silicon dioxide layers using isotopically pure material  

International Nuclear Information System (INIS)

[en] We report measurement of the silicon diffusion coefficient in silicon dioxide films using isotopically enriched 28Si silicon dioxide layers that enable relatively low 30Si concentration measurements to be performed using secondary ion mass spectrometry. Two types of experiments are made. 30Si atoms are introduced in excess in a stoichiometric isotopically pure silicon dioxide layer either by ion implantation or by a predeposition technique. These experiments are representative of any physical situation in which excess silicon atoms are introduced into silicon dioxide layers during silicon processing. The estimated diffusivity values are significantly higher than previously reported values for Si diffusion within a stoichiometric oxide and closer to reported values for excess Si diffusion within an oxide. The activation energy of the diffusivity is found to be 4.74 eV. [copyright] 2001 American Institute of Physics

2001-06-15

274

Diffusivity measurements of silicon in silicon dioxide layers using isotopically pure material  

Energy Technology Data Exchange (ETDEWEB)

We report measurement of the silicon diffusion coefficient in silicon dioxide films using isotopically enriched {sup 28}Si silicon dioxide layers that enable relatively low {sup 30}Si concentration measurements to be performed using secondary ion mass spectrometry. Two types of experiments are made. {sup 30}Si atoms are introduced in excess in a stoichiometric isotopically pure silicon dioxide layer either by ion implantation or by a predeposition technique. These experiments are representative of any physical situation in which excess silicon atoms are introduced into silicon dioxide layers during silicon processing. The estimated diffusivity values are significantly higher than previously reported values for Si diffusion within a stoichiometric oxide and closer to reported values for excess Si diffusion within an oxide. The activation energy of the diffusivity is found to be 4.74 eV. {copyright} 2001 American Institute of Physics.

Tsoukalas, D.; Tsamis, C.; Normand, P.

2001-06-15

275

Surface wave propagation in a swelling porous elastic material under a inviscid liquid layer  

Directory of Open Access Journals (Sweden)

Full Text Available The present investigation is to study the surface wave propagationin a swelling porous elastic half space under homogeneous inviscidliquid layer. The frequency equation is derive for both swellingporous (SP) and without swelling porous (elastic medium) (EL) medium. The dispersion curves giving the phase velocity and attenuation coefficient with wave number are plotted graphically to depict the effect of swelling porous half space under a homogeneous inviscid liquid layer. The amplitudes of displacement in both SP and EL medium are obtained and are shown graphically. Some special cases are also deduced from the present investigation.

Rajneesh Kumar; Divya; Kuldeep Kumar

2010-01-01

276

A replacement of high-k process for CMOS transistor by atomic layer deposition  

Science.gov (United States)

A replacement of high-k process was implemented on an independent double gate FinFET, following the ordinary gate-first process with minor modifications. The present scheme involves neither exotic materials nor unprecedented processing. After the source/drain process, the sacrificial gate oxide was selectively substituted with amorphous Ta2O5 via conformal plasma enhanced atomic layer deposition. The present gate-first gate-dielectric-last scheme combines the advantages of the process and design simplicity of the gate-first approach and the control of the effective gate workfunction and the interfacial oxide of the gate-dielectric-last approach. Electrical characterization data and cross-sectional images are provided as evidence of the concept.

Han, Jin-Woo; Choi, Byung Joon; Yang, J. Joshua; Moon, Dong-Il; Choi, Yang-Kyu; Williams, R. Stanley; Meyyappan, M.

2013-08-01

277

Preparation and Characterization of TiO2/CdS Layers as Potential Photoelectrocatalytic Materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The TiO2/CdS semiconductor composites were prepared on
indium tin oxide (ITO) substrates in di®erent mass proportions via wet-chemical techniques using bi-distilled water, acetyl-acetone, poly-propylene-glycol and Triton X-100 as additives. The composite layers were annealed in normal...

Marcela-Corina Rosu; Ramona-Crina Suciu; Simina-Virginia Dreve; Ioan Bratu; Teofil-Danut Silipas; Emil Indrea

278

Elastic properties of a material composed of alternating layers of negative and positive Poisson's ratio  

Energy Technology Data Exchange (ETDEWEB)

The theory of elasticity predicts a variety of phenomena associated with solids that possess a negative Poisson's ratio. The fabrication of metamaterials with a 'designed' microstructure that exhibit a Poisson's ratio approaching the thermodynamic limits of 1/2 and -1 increases the likelihood of realising these phenomena for applications. In this work, we investigate the properties of a layered composite, with alternating layers of materials with negative and positive Poisson's ratio approaching the thermodynamic limits. Using the finite element method to simulate uniaxial loading and indentation of a free standing composite, we observed an increase in the resistance to mechanical deformation above the average value of the two materials. Even though the greatest increase in stiffness is gained as the thermodynamic limits are approached, a significant amount of added stiffness can be attained, provided that the Young's modulus of the negative Poisson's ratio material is not less than that of the positive Poisson's ratio material.

Kocer, C. [University of Sydney, School of Physics, Sydney, NSW, 2006 (Australia)], E-mail: c.kocer@physics.usyd.edu.au; McKenzie, D.R.; Bilek, M.M. [University of Sydney, School of Physics, Sydney, NSW, 2006 (Australia)

2009-04-15

279

Cathodic protection by zinc sacrificial anodes: impact on marine sediment metallic contamination.  

Science.gov (United States)

Cathodic protection by sacrificial zinc anodes is often applied to prevent immerged metallic structures from corrosion. But this technique induces the zinc anodes dissolution, which can induce marine sediments and seawater contamination. A large scale experiment, in natural seawater, was conducted during 12 months, in order to evaluate the potential environmental impact of this continuous zinc dissolution, and of some necessary cleaning operations of the anodes surfaces. The heavy metal (Cr, Cu, Pb and Zn) concentration in water and sediment samples was monitored. A sequential extraction procedure was applied on sediment samples to differentiate the zinc mobile fractions from the residual one. A significant increase of zinc concentration was observed in water as well as in the surface sediments under the specific operating conditions. Sediments then become a secondary pollution source, as the sorbed labile zinc can be remobilized to seawater. PMID:19250740

Rousseau, C; Baraud, F; Leleyter, L; Gil, O

2009-01-30

280

Cathodic protection by zinc sacrificial anodes: impact on marine sediment metallic contamination.  

UK PubMed Central (United Kingdom)

Cathodic protection by sacrificial zinc anodes is often applied to prevent immerged metallic structures from corrosion. But this technique induces the zinc anodes dissolution, which can induce marine sediments and seawater contamination. A large scale experiment, in natural seawater, was conducted during 12 months, in order to evaluate the potential environmental impact of this continuous zinc dissolution, and of some necessary cleaning operations of the anodes surfaces. The heavy metal (Cr, Cu, Pb and Zn) concentration in water and sediment samples was monitored. A sequential extraction procedure was applied on sediment samples to differentiate the zinc mobile fractions from the residual one. A significant increase of zinc concentration was observed in water as well as in the surface sediments under the specific operating conditions. Sediments then become a secondary pollution source, as the sorbed labile zinc can be remobilized to seawater.

Rousseau C; Baraud F; Leleyter L; Gil O

2009-08-01

 
 
 
 
281

Sacrificial adsorbate for surfactants utilized in chemical floods of enhanced oil recovery operations  

Energy Technology Data Exchange (ETDEWEB)

The present invention is directed to a sacrificial or competitive adsorbate for surfactants contained in chemical flooding emulsions for enhanced oil recovery operations. The adsorbate to be utilized in the method of the present invention is a caustic effluent from the bleach stage or the weak black liquor from the digesters and pulp washers of the kraft pulping process. This effluent or weak black liquor is injected into an oil-bearing subterranean earth formation prior to or concurrent with the chemical flood emulsion and is adsorbed on the active mineral surfaces of the formation matrix so as to effectively reduce adsorption of surfactant in the chemical flood. Alternatively, the effluent or liquor can be injected into the subterranean earth formation subsequent to a chemical flood to displace the surfactant from the mineral surfaces for the recovery thereof.

Johnson, Jr., James S. (Oak Ridge, TN); Westmoreland, Clyde G. (Rockwood, TN)

1982-01-01

282

Bonding Semiconductor Laser Chips : Substrate Material Figure of Merit and Die Attach Layer Influence  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The coefficient of thermal expansion (CTE) and the thermal conductivity are the two key parameters to consider when selecting a particular substrate material for a die bonding process. We will discuss here a model to determine the substrate material giving the best chip reliability expectations for ...

Pliska, A.-C.; Mottin, J.; Matuschek, N.; Bosshard, C.

283

Fabrication of tubed functionally graded material by slurry dipping process. Thickness control of dip-coated layer  

Energy Technology Data Exchange (ETDEWEB)

In order to obtain long life fuel cladding tubes for the fast breeder reactor, the concept of functionally graded material was applied for the material combination of Molybdenum/stainless steel/Titanium, in which Titanium and Molybdenum were placed at the inner and outer sides, respectively. Slurry dipping method was employed because of its capability of shape forming and microstructural control. We have hitherto reported the design criteria for the graded layers, preparation of the slurry, and microstructural control of the dip-coated layers. In the present report, the thickness control of the dip-coated layer is described in detail. The thickness of the dip-coated layer depends primarily on the viscosity of the slurry. Nevertheless, for the stable dispersion of the powder in the slurry, which dominates the microstructural homogeneity, an optimum viscosity value is present for the individual slurries. With stable slurries of Ti, Mo, stainless steel powders and their mixtures, the thicknesses of dip-coated layers were controlled in dependence of their viscosities and yield values. For Ti and stainless steel powders and their mixture a PAANa was used as a dispersing agent. A NaHMP was found to be effective for the dispersion of Mo powder and Mo/stainless steel powder mixture. For all slurries tested in the present investigation PVA addition was helpful for the viscosity control. Dip-coating maps have been drawn for the stabilization of the slurries and for the formation of films with a sufficient strength for further manipulation for the slurries with low viscosity ({approx}10 mPa s). The final film thickness for the low-viscosity slurry with the optimum condition was about 200 {mu}m. The slurries with high viscosities of several hundreds mPa s had a good stability and the yield value was easy to be controlled. The film thickness was able to be adjusted in the size range between several tens and several hundreds {mu}m. The final thickness of the graded layer was determined on the basis of the material balance involved and densification ratio attained by drying, sintering and HIP treatment processes. (author)

Watanabe, Ryuzo [Tohoku Univ., Sendai (Japan). Dept. of Materials Processing

1997-03-01

284

Single-layered V2O5 a promising cathode material for rechargeable Li and Mg ion batteries: an ab initio study.  

UK PubMed Central (United Kingdom)

Using first principles calculations based on density functional theory, the adsorption and diffusion properties of Li and Mg atoms on single-layered and bulk V2O5 are investigated. The simulation results show that the diffusion barrier of Li on the single-layered V2O5 is decreased compared with that of the bulk V2O5, which indicates that the Li mobility can be significantly enhanced on the single-layered V2O5. The increased binding energies of Li to single-layered V2O5 make them more attractive for promising cathode materials. Although the diffusion barrier of Mg on the single-layered V2O5 does not decrease, the binding energies of Mg to single-layered V2O5 is increased compared with that of bulk V2O5, thus the single-layered V2O5 is an attractive cathode material for rechargeable ion batteries.

Wang Z; Su Q; Deng H

2013-06-01

285

Application of thin layer activation technique for surface wear studies in Zr based materials using charged particle induced nuclear reactions  

Energy Technology Data Exchange (ETDEWEB)

Thin layer activation (TLA) technique has been developed in Zr based alloy materials, e.g., zircaloy II, using 40 MeV {alpha}-particles from variable energy cyclotron centre at Calcutta. A brief description of the methodology of TLA technique is presented to determine the surface wear. The sensitivity of the measurement of surface wear in zircaloy material is found to be 0.22{+-}0.05 {mu}m. The surface wear is determined by TLA technique in zircaloy material which is used in pressurised heavy water reactor and the values have been compared with that obtained by conventional technique for the analytical validation of the TLA technique. (orig.) 13 refs.

Chowdhury, D.P.; Pal, Sujit [Bhabha Atomic Research Centre, Calcutta (India). Variable Energy Cyclotron Centre; Parthasarathy, R.; Mathur, P.K. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kohli, A.K. [Technology Transfer and Collaboration Division, Bhabha Atomic Research Centre, Hall-7, Mumbai 400085 (India); Limaye, P.K. [Refuelling Technology Division, Bhabha Atomic Research Centre, Hall-7, Mumbai 400085 (India)

1998-09-01

286

Post-thermocycling shear bond strength of a gingiva-colored indirect composite layering material to three implant framework materials.  

Science.gov (United States)

Abstract Objective. To evaluate shear bond strength of a gingiva-colored indirect composite to three implant framework materials, before and after thermocycling, and verify the effect of surface pre-treatment for each framework. Materials and methods. Commercially pure titanium (CP-Ti), American Dental Association (ADA) type 4 casting gold alloy (Type IV) and zirconia ceramics (Zirconia) were assessed. For each substrate, 96 disks were divided into six groups and primed with one of the following primers: Alloy Primer (ALP), Clearfil Photo Bond (CPB), Clearfil Photo Bond with Clearfil Porcelain Bond Activator (CPB+Activator), Estenia Opaque Primer (EOP), Metal Link (MLP) and V-Primer (VPR). The specimens were then bonded to a gingiva-colored indirect composite (Ceramage Concentrate GUM-D). Shear bond strengths were measured at 0 and 20 000 thermocycles and data were analyzed with the Steel-Dwass test and Mann-Whitney U-test. Results. Shear bond strengths were significantly lower after thermocycling, with the exception of Type IV specimens primed with CPB (p = 0.092) or MLP (p = 0.112). For CP-Ti and Zirconia specimens, priming with CPB or CPB+Activator produced significantly higher bond strengths at 0 and 20 000 thermocycles, as compared with the other groups. For Type IV specimens, priming with ALP or MLP produced higher bond strengths at 0 and 20 000 thermocycles. Conclusions. Shear bond strength of a gingiva-colored indirect composite to CP-Ti, gold alloy and zirconia ceramics was generally lower after thermocycling. Application of a hydrophobic phosphate monomer and polymerization initiator was effective in maintaining bond strength of CP-Ti and zirconia ceramics. Combined use of a thione monomer and phosphoric monomer enhanced the durable bond strength of gold alloy. PMID:23163257

Komine, Futoshi; Koizuka, Mai; Fushiki, Ryosuke; Taguchi, Kohei; Kamio, Shingo; Matsumura, Hideo

2012-11-19

287

Measurement of material properties of individual layers for composite films by a pull-in method  

Energy Technology Data Exchange (ETDEWEB)

There has been an increasing need for MEMS devices with composite films in recent years. This paper presents an improved model of pull-in voltage by finite-difference method (FDM) for a composite fixed-fixed beam, which takes influence of lateral residual stresses of each layer into account. Young's modulus and residual stresses of each layer for composite beam can then be extracted by these pull-in voltages. And fixed-fixed surface machined beams with multi-cup style anchor were fabricated to be suitable to the model of pull-in voltage. Validation and accuracy of the extracting method have been verified by FEM simulation and experiments.

Nie Meng; Huang Qingan; Li Weihua [Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing, 210096 (China)

2006-04-01

288

Experiments on passive hypersonic boundary layer control using ultrasonically absorptive carbon-carbon material with random microstructure  

Science.gov (United States)

For the first time, the influence of ultrasonically absorptive carbon-carbon material on hypersonic laminar to turbulent boundary layer transition was investigated experimentally. A 7° half-angle blunted cone with a nose radius of 2.5 mm and a total length of 1,077 mm was tested at zero angle of attack in the High Enthalpy Shock Tunnel Göttingen of the German Aerospace Center (DLR) at Mach 7.5. One-third of the metallic model surface in circumferential direction was replaced by DLR in-house manufactured ultrasonically absorptive carbon-carbon material with random microstructure for passive transition control. The remaining model surface consisted of polished steel and served as reference surface. The model was equipped with coaxial thermocouples to determine the transition location by means of surface heat flux distribution. Flush-mounted piezoelectric fast-response pressure transducers were used to measure the pressure fluctuations in the boundary layer associated with second-mode instabilities. The free-stream unit Reynolds number was varied over a range of Re m = 1.5 × 106 m-1 to Re m = 6.4 × 106 m-1 at a stagnation enthalpy of h 0 ? 3.2 MJ/kg and a wall temperature ratio of T w/ T 0 ? 0.1. The present study revealed a clear damping of the second-mode instabilities and a delay of boundary layer transition along the ultrasonically absorptive carbon-carbon insert.

Wagner, Alexander; Kuhn, Markus; Martinez Schramm, Jan; Hannemann, Klaus

2013-10-01

289

The Interaction Between a Beam and a Layer of Microwave-Absorbing Material  

Science.gov (United States)

A phased luminosity upgrade of the CESR electron -positron storage ring is in progress. The upgrade program calls for the installation of superconducting radio-frequency (RF) cavities with strongly damped higher-order modes (HOMs). The cavity is designed to allow all HOMs to propagate into the beam pipe, where they are damped by a layer of microwave -absorbing ferrite. RF measurements with a copper cavity and loads made of a nickel-zinc ferrite indicate that the design gives adequate HOM damping. Because the absorbing layer is on the beam pipe, there is a direct parasitic interaction with the beam. To quantify this parasitic interaction, the complex permeability and complex permittivity of the ferrite were measured as a function of frequency. These results were used to predict the beam coupling impedance of the ferrite loads via numerical and analytic techniques. The predictive methods were checked using the pulse-on-a-wire method for measuring the coupling impedance. Beam stability predictions based on the calculated impedance indicate that there should be no beam instabilities due to the direct interaction between the beam and the ferrite layer for a 183-bunch beam with a total current of 2 A per beam. The average power dissipation in the ferrite, including both direct and indirect power transfer from the beam, is predicted to be 82 W/cm^2 with 2 A per beam. To test the predictions, beam measurements were done in CESR on a ferrite load of magnified coupling impedance. The beam-induced power dissipation in the ferrite layer was within a factor of 2 of the predicted value. It was difficult to see an effect on the beam due to the presence of the ferrite, a result that is consistent with our present understanding.

Hartung, Walter H.

290

Mass exchange in adjacent layers of grain material stored in silo  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents the results of a study on the process of moisture diffusion during barley grain storage in a grain storage silo. The moisture migration was caused by concentration gradient. The study was conducted using a model test station and consisted in the measurement of barley grain moisture and temperature in a silo, and in measuring the pressure exerted by the grain bulk on the silo wall. Analysis of the results showed that none of the parameters studied was stable. It was found that when the grain moisture content applied was 16% in the bottom layer and 10% in the upper layer the average value of grain moisture content in the silo increased from 13.2% to 14.1% over the ten days of the process, while with reverse positioning of the layers in the silo the corresponding increase reached 13.8%. This was due to additional precipitation of water in the course of the process of grain respiration. Moisture diffusion caused an increase in the temperature of the grain within the silo (up to 33°C at ambient temperature of 16°C). Another important effect of the moisture diffusion was the swelling of grains, which caused an increase in the pressure of the barley grain bulk against the silo wall. The highest increase in the wall load was observed at the boundary line between layers of grain of different moisture content levels. The changes in the values of the parameters under study were described by means of regression equations.

Grochowicz J.; Kusińska E.; Bilański W.K.

1998-01-01

291

Colloidal semiconductors in systems for the sacrificial photolysis of water: sensitization of TiO/sub 2/ by adsorption of ruthenium complexes  

Energy Technology Data Exchange (ETDEWEB)

Adsorbed tris(2,2'-bipyridine-4,4'-dicarboxylic acid)ruthenium(II) molecules (Ru/sup II/(acid)/sub 3/) sensitize the production of H/sub 2/ that occurs when Pt/TiO/sub 2/ dispersions are illuminated with visible light in the presence of EDTA as sacrificial electron donor. Ru/sup II/(acid)/sub 3/ adsorbs on TiO/sub 2/ at pH values below the isoelectric point of the TiO/sub 2/ (6.1) in response to electrostatic attraction between its dissociated species and positively charged TiO/sub 2/ particles. In contrast to band-gap systems, sensitized systems are not regenerated by readjustment of pH and addition of electron donor. Clearly, sensitization requires adsorption of sensitizer in the first adsorbed layer in addition to favorable redox potentials for electron injection from sensitizer into the conduction band of the TiO/sub 2/ particles. Multilayers of sensitizer do not assist electron injection but instead reduce the amount of light available to the first adsorbed layer. 50 references, 8 figures, 4 tables.

Furlong, D.N.; Wells, D.; Sasse, W.H.F.

1986-03-13

292

Preparation and Characterization of TiO2/CdS Layers as Potential Photoelectrocatalytic Materials  

Directory of Open Access Journals (Sweden)

Full Text Available The TiO2/CdS semiconductor composites were prepared onindium tin oxide (ITO) substrates in di®erent mass proportions via wet-chemical techniques using bi-distilled water, acetyl-acetone, poly-propylene-glycol and Triton X-100 as additives. The composite layers were annealed in normal conditions at the temperature of 450±C, 120 min. with a rate of temperature increasing of 5±C/min. The structural and optical properties of all the TiO2/CdS ayers were characterized by X-ray di®raction, UV-VIS spectroscopy, spectrofluorimetry and FT/IR microscopy. The microstructural properties of the deposited TiO2/CdS layers can be modi¯ed by varying the mass proportions of TiO2:CdS. The good crystallinity level and the high optical adsorption ofthe TiO2/CdS layers make them attractive for photoelectrochemical cell applications.

Marcela-Corina Rosu; Ramona-Crina Suciu; Simina-Virginia Dreve; Ioan Bratu; Teofil-Danut Silipas; Emil Indrea

2011-01-01

293

Shape-selective sieving layers on an oxide catalyst surface.  

UK PubMed Central (United Kingdom)

New porous materials such as zeolites, metal-organic frameworks and mesostructured oxides are of immense practical utility for gas storage, separations and heterogeneous catalysis. Their extended pore structures enable selective uptake of molecules or can modify the product selectivity (regioselectivity or enantioselectivity) of catalyst sites contained within. However, diffusion within pores can be problematic for biomass and fine chemicals, and not all catalyst classes can be readily synthesized with pores of the correct dimensions. Here, we present a novel approach that adds reactant selectivity to existing, non-porous oxide catalysts by first grafting the catalyst particles with single-molecule sacrificial templates, then partially overcoating the catalyst with a second oxide through atomic layer deposition. This technique is used to create sieving layers of Al(2)O(3) (thickness, 0.4-0.7 nm) with 'nanocavities' (<2 nm in diameter) on a TiO(2) photocatalyst. The additional layers result in selectivity (up to 9:1) towards less hindered reactants in otherwise unselective, competitive photocatalytic oxidations and transfer hydrogenations.

Canlas CP; Lu J; Ray NA; Grosso-Giordano NA; Lee S; Elam JW; Winans RE; Van Duyne RP; Stair PC; Notestein JM

2012-12-01

294

Wear of metal materials in a granular layer fluidized with a liquid  

Energy Technology Data Exchange (ETDEWEB)

The Volgograd Petroleum Machinery Production Union has made investigations of the kinetics of wear of surfaces in contact with the granular material in a fluidized bed for the purpose of obtaining data on the selection of materials for the design elements of apparatus and the filler used to provide the minimum wear, determination of the necessary wall thickness of the apparatus, and predicting the service life between repairs of their design elements. Indicates that in processes with a fluidized bed the influence of the corrosion factor of materials increases since the wear process is slower and the time between the preceding and next actions of a particle on the material being worn increases. The influence of corrosion on their resistance to hydroabrasive wear was also determined on 08Kh18N10T steel samples.

Lebas, E.P.

1982-11-01

295

Characterization of sputtered indium tin oxide layers as transparent contact material  

International Nuclear Information System (INIS)

The electrical, optical, and various mechanical properties of rf sputtered indium tin oxide layers were investigated in terms of electrical resistivity (four-probe measurement and Hall), optical transparency, scanning transmission electron spectroscopy and x-ray spectroscopy. Whereas the specific conductivity is at the lower limit reported in the literature (2x10-4 ? cm), and the optical transparency is as high as 90% in the wavelength range between 550 and 800 nm, the grain size is between 10 and 25 nm. The stress is tensile and in the range of 7 kbar after deposition, to drop to 3 kbar after anneal.

2001-01-01

296

The motion of low energy electrons in thin layers of amorphous materials  

International Nuclear Information System (INIS)

[en] Recently there have been experiments which precisely measure the transmitted current of low energy electrons (0 - 15 eV) through thin layers of matter. The authors aim at a theoretical description of such experiments by representing relevant observable quantities in terms of the autocorrelation of the potential which the electron experiences, in scattering through the medium. For example, the current which is detected may be expresses as a cumulant expansion, the various terms representing the action of the medium on the electron. The cumulants may serve as coefficients of a Langevin type equation. An outline and discussion of the approach is given

1985-01-01

297

Design of special selective radiating materials using thermochromic films as the second layer; Thermochromic maku wo dainiso to shite mochiita sentaku hosha zairyo no sekkei  

Energy Technology Data Exchange (ETDEWEB)

Simulation of radiative cooling of newly designed spectral selective radiating materials was carried out. The selective radiating materials were composed of silicon monoxide and a thermochromic film, such as a VO2 film or a W doped VO2 film, and blackbody as the first layer, the second layer, and the substrate, respectively. The simulation revealed that these materials have an advantage of high stability of temperature which can be controlled by changing the critical temperature of the second layer. 22 refs., 6 figs.

Tazawa, M.; Miki, T.; Yoshimura, K.; Jin, P.; Tanemura, S. [National Industrial Research Institute of Nagoya, Nagoya (Japan)

1995-08-04

298

Graphene quantum dots as the hole transport layer material for high-performance organic solar cells.  

UK PubMed Central (United Kingdom)

We present an investigation of organic photovoltaic (OPV) cells with solution-processable graphene quantum dots (GQDs) as hole transport layers (HTLs). GQDs, with uniform sizes and good conductivity, are demonstrated to be excellent HTLs in both polymer solar cells (PSCs) and small-molecule solar cells (SMSCs) with the blend of poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) and small molecule DR3TBDT:[6,6]-phenyl-C71-butyric acid methyl ester (DR3TBDT:PC71M) as the active layer, respectively. The PSCs and SMSCs based on GQDs yield power conversion efficiencies of 3.51% and 6.82%, respectively, both comparable to those of solar cells with PEDOT:PSS as the HTLs. In addition, the cells with GQDs as HTLs exhibit much more reproducible performance and longer lifetime. In light of the high stability, low cost and easy processing, these results indicate that GQDs can be potentially used to replace PEDOT:PSS for producing high-performance and stable organic photovoltaic cells.

Li M; Ni W; Kan B; Wan X; Zhang L; Zhang Q; Long G; Zuo Y; Chen Y

2013-10-01

299

Graphene quantum dots as the hole transport layer material for high-performance organic solar cells.  

Science.gov (United States)

We present an investigation of organic photovoltaic (OPV) cells with solution-processable graphene quantum dots (GQDs) as hole transport layers (HTLs). GQDs, with uniform sizes and good conductivity, are demonstrated to be excellent HTLs in both polymer solar cells (PSCs) and small-molecule solar cells (SMSCs) with the blend of poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PC61BM) and small molecule DR3TBDT:[6,6]-phenyl-C71-butyric acid methyl ester (DR3TBDT:PC71M) as the active layer, respectively. The PSCs and SMSCs based on GQDs yield power conversion efficiencies of 3.51% and 6.82%, respectively, both comparable to those of solar cells with PEDOT:PSS as the HTLs. In addition, the cells with GQDs as HTLs exhibit much more reproducible performance and longer lifetime. In light of the high stability, low cost and easy processing, these results indicate that GQDs can be potentially used to replace PEDOT:PSS for producing high-performance and stable organic photovoltaic cells. PMID:24097209

Li, Miaomiao; Ni, Wang; Kan, Bin; Wan, Xiangjian; Zhang, Long; Zhang, Qian; Long, Guankui; Zuo, Yi; Chen, Yongsheng

2013-10-16

300

Collision of a vortex ring on granular material. Part II. Erosion of the granular layer  

International Nuclear Information System (INIS)

In our previous paper (part I), an experimental result was presented on the normal impact of a vortex ring on the granular layer (glass beads of diameter 0.10 mm), which was placed at a specified distance from the outlet of the vortex ring generator. The Reynolds number of the vortex ring ranged from 1000 to 6000, whereas the traveling distance ranged from 2 to 13 times of the diameter of the vortex ring generator nozzle. In part I, the deformation of the vortex ring impacting on the granular layer and the development of the secondary vortex ring were focused. In this paper (part II), the erosion of the granular surface by the vortex ring is described. Various patterns were found depending on the Reynolds number of the vortex ring and the traveling distance. Two patterns, one (grooves) which has radial striations from the central depressed region to the outer edge of the rim and the other (dimples) which is characterized by isolated small depressions around the outer edge of the rim, are examined in detail. The formation processes of these patterns are elucidated in terms of the deformation of the vortex ring. (paper)

2012-02-01

 
 
 
 
301

Layered carbon nanotube-polyelectrolyte electrodes outperform traditional neural interface materials.  

UK PubMed Central (United Kingdom)

The safety, function, and longevity of implantable neuroprosthetic and cardiostimulating electrodes depend heavily on the electrical properties of the electrode-tissue interface, which in many cases requires substantial improvement. While different variations of carbon nanotube materials have been shown to be suitable for neural excitation, it is critical to evaluate them versus other materials used for bioelectrical interfacing, which have not been done in any study performed so far despite strong interest to this area. In this study, we carried out this evaluation and found that composite multiwalled carbon nanotube-polyelectrolyte (MWNT-PE) multilayer electrodes substantially outperform in one way or the other state-of-the-art neural interface materials available today, namely activated electrochemically deposited iridium oxide (IrOx) and poly(3,4-ethylenedioxythiophene) (PEDOT). Our findings provide the concrete experimental proof to the much discussed possibility that carbon nanotube composites can serve as excellent new material for neural interfacing with a strong possibility to lead to a new generation of implantable electrodes.

Jan E; Hendricks JL; Husaini V; Richardson-Burns SM; Sereno A; Martin DC; Kotov NA

2009-12-01

302

Positron lifetimes and distributions in the infinite-layer compound SrCuO2 and related materials  

International Nuclear Information System (INIS)

[en] We have calculated distributions and lifetimes of positrons in the infinite-layer compound SrCuO2 and those trapped at possible point defects therein. In the delocalized state, positrons show their density maxima at interstitial sites in the Sr planes and have a significant overlap also with Cu and O atoms. The corresponding positron lifetime is 149 ps. It has been revealed that the Sr vacancy strongly localizes positrons with the binding energy of 2.8 eV and the lifetime of 238 ps, while the O vacancy does not trap positrons. Calculations are also performed on related materials Sr2Cu4O6 and Sr4Cu6O10, which are characterized by one-dimensional networks of edge-sharing CuO4 squares. Positrons are predominantly distributed between these networks in these materials and their corresponding lifetimes are 170-171 ps. (orig.)

1992-09-02

303

Layered double hydroxides intercalated with anionic surfactants/benzophenone as potential materials for sunscreens.  

UK PubMed Central (United Kingdom)

Layered double hydroxides intercalated with dodecylsulfate or dodecylbenzenesulfonate were synthesized by co-precipitation under alkaline conditions. After characterization by PXRD, FTIR, and TGA/DTA, the ZnxAl/SUR compounds were reacted with neutral benzophenone, using different procedures. The products obtained from benzophenone adsolubilization were investigated by PXRD, FTIR, and DRUV-Vis spectroscopy before and after exposure to UV radiation. In general, the content of adsolubilized benzophenone was small and depended on the synthetic procedure. The best results were achieved under microwave irradiation, which furnished 9.09 wt% adsolubilized benzophenone. The products presented good adsorption in the full UV region, from UVC to UVA, and good stability to UV radiation. They did not cause skin irritation in tests conducted on rabbits, which makes them good candidates for the development of a new generation of sunscreens.

Cursino AC; Lisboa Fda S; Pyrrho Ados S; de Sousa VP; Wypych F

2013-05-01

304

New lead inorganic-organic hybrid microporous and layered materials: synthesis, properties, and crystal structures.  

UK PubMed Central (United Kingdom)

Two new lead(II) phosphonates, namely, Pb2[PMIDA]*1.5H2O (1) (H4PMIDA = H2O3PCH2N(CH2CO2H)2) and Pb(H2L) (2) (H4L = CH3N(CH2PO3H2)2), have been synthesized by hydrothermal reactions at 150 degrees C. Complex 1 crystallized in tetragonal P42/n with cell dimensions of a = 17.317(7) and c = 7.507(5) A and Z = 8. In complex 1, Pb(1) is 6-coordinated by chelation in a tetradentate fashion by a PMIDA ligand (3 O, 1 N) and two phosphonate oxygen atoms from neighboring Pb(PMIDA) units in a severely distorted octahedral geometry, whereas Pb(2) is 6-coordinated by 4 carboxylate and 2 phosphonate oxygen atoms also with a severely distorted octahedral environment. These two different types of Pb(II) ions are interconnected through bridging carboxylate and phosphonate groups, resulting in a 3D network with micropores, whose cavity is filled by lattice water molecules interlinked via hydrogen bonds. Each PMIDA ligand bridges with 8 Pb(II) ions (3 Pb(1) and 5 Pb(2)). Complex 2 is orthorhombic, P2(1)2(1)2(1), with a = 7.382(5), b = 7.440(6), and c = 30.75(2) A and Z = 8. The structure of 2 features a 2D double lead(II) phosphonate layer along the ab plane. Each lead(II) ion is 5-coordinated by five phosphonate oxygen atoms from four ligands in a distorted trigonal bipyramid geometry. These double layers are further interconnected via hydrogen bonds between the protonated and uncoordinated phosphonate oxygens along the c-axis.

Mao JG; Wang Z; Clearfield A

2002-11-01

305

New lead inorganic-organic hybrid microporous and layered materials: synthesis, properties, and crystal structures.  

Science.gov (United States)

Two new lead(II) phosphonates, namely, Pb2[PMIDA]*1.5H2O (1) (H4PMIDA = H2O3PCH2N(CH2CO2H)2) and Pb(H2L) (2) (H4L = CH3N(CH2PO3H2)2), have been synthesized by hydrothermal reactions at 150 degrees C. Complex 1 crystallized in tetragonal P42/n with cell dimensions of a = 17.317(7) and c = 7.507(5) A and Z = 8. In complex 1, Pb(1) is 6-coordinated by chelation in a tetradentate fashion by a PMIDA ligand (3 O, 1 N) and two phosphonate oxygen atoms from neighboring Pb(PMIDA) units in a severely distorted octahedral geometry, whereas Pb(2) is 6-coordinated by 4 carboxylate and 2 phosphonate oxygen atoms also with a severely distorted octahedral environment. These two different types of Pb(II) ions are interconnected through bridging carboxylate and phosphonate groups, resulting in a 3D network with micropores, whose cavity is filled by lattice water molecules interlinked via hydrogen bonds. Each PMIDA ligand bridges with 8 Pb(II) ions (3 Pb(1) and 5 Pb(2)). Complex 2 is orthorhombic, P2(1)2(1)2(1), with a = 7.382(5), b = 7.440(6), and c = 30.75(2) A and Z = 8. The structure of 2 features a 2D double lead(II) phosphonate layer along the ab plane. Each lead(II) ion is 5-coordinated by five phosphonate oxygen atoms from four ligands in a distorted trigonal bipyramid geometry. These double layers are further interconnected via hydrogen bonds between the protonated and uncoordinated phosphonate oxygens along the c-axis. PMID:12425639

Mao, Jiang-Gao; Wang, Zhike; Clearfield, Abraham

2002-11-18

306

Recycled waste paper - A new source of raw material for electric double-layer capacitors  

Energy Technology Data Exchange (ETDEWEB)

For the first time, a new carbon-carbon composite electrode material for supercapacitors is prepared by simple KOH activation of waste newspaper. The amorphous nature and surface morphology of the carbon composite are investigated by X-ray diffraction (XRD), N{sub 2} adsorption/desorption and scanning electron microscopy. The surface area and pore diameter are 416 m{sup 2} g{sup -1} and 5.9 nm, respectively. Electrochemical characteristics are evaluated by cyclic voltammetry (CV) and charge-discharge tests in 6.0 M KOH at a 1 mA cm{sup -2} current density. The CV results reveal a maximum specific capacitance of 180 F g{sup -1} at a 2 mV s{sup -1} scan rate and the data explore a development of new use for waste paper into a valuable energy storage material. (author)

Kalpana, D. [The Research Institute for Catalysis, Chonnam National University, Gwangju 500-757 (Korea); National Environmental Engineering Research Institute, Nagpur 440 020 (India); Cho, S.H.; Lee, S.B.; Lee, Y.S. [Faculty of Applied Chemical Engineering, Chonnam National University, Gwangju 500-757 (Korea); Misra, Rohit [National Environmental Engineering Research Institute, Nagpur 440 020 (India); Renganathan, N.G. [Central Electrochemical Research Institute, Karaikudi 630 006 (India)

2009-05-15

307

Optical coherence tomography enabling non destructive metrology of layered polymeric GRIN material.  

UK PubMed Central (United Kingdom)

Gradient Refractive INdex (GRIN) optical components have historically fallen short of theoretical expectations. A recent breakthrough is the manufacturing of nanolayered spherical GRIN (S-GRIN) polymer optical elements, where the construction method yields refractive index gradients that exceed 0.08. Here we report on the application of optical coherence tomography (OCT), including micron-class axial and lateral resolution advances, as effective, innovative methods for performing nondestructive diagnostic metrology on S-GRIN. We show that OCT can be used to visualize and quantify characteristics of the material throughout the manufacturing process. Specifically, internal film structure may be revealed and data are processed to extract sub-surface profiles of each internal film of the material to quantify 3D film thickness and homogeneity. The technique provides direct feedback into the fabrication process directed at optimizing the quality of the nanolayered S-GRIN polymer optical components.

Meemon P; Yao J; Lee KS; Thompson KP; Ponting M; Baer E; Rolland JP

2013-01-01

308

The application of a layer of carbonaceous material to a surface  

International Nuclear Information System (INIS)

A method of applying a carbonaceous material to a surface is described. It consists of exposing the surface to an ionised gas atmosphere generated in a gas consisting substantially of carbon and hydrogen, and applying to the surface through capacitive means an electrical potential which changes in sign at time intervals of between 5 x 10-9 seconds and 10-6 seconds. (author)

1981-01-01

309

The Prospect of Y2SiO5-Based Materials as Protective Layer in Environmental Barrier Coatings  

Science.gov (United States)

Bulk yttrium monosilicate (Y2SiO5) possesses interesting properties, such as low thermal expansion coefficient and stability in water vapor atmospheres, which make it a promising protective layer for SiC-based composites, intended for the hottest parts in the future gas turbines. Because protective layers are commonly applied by thermal spraying techniques, it is important to analyze the changes in structure and properties that these methods may produce in yttrium silicate coatings. In this work, two SiO2-Y2O3 compositions were flame sprayed in the form of coatings and beads. In parallel, the beads were spark plasma sintered at relatively low temperature to obtain partially amorphous bulk specimens that are used as model bulk material. The thermal aging—air and water vapor atmosphere—caused extensive nucleation of Y2SiO5 and Y2Si2O7 in both the bulk and coating. The rich water vapor condition caused the selective volatilization of SiO2 from Y2Si2O7 at the specimen surface leaving a very characteristic micro-ridged Y2SiO5 zones—either in coatings or sintered bodies. An important increase in the thermal conductivity of the aged materials was measured. The results of this work may be used as a reference body for the production of Y2SiO5 coatings using thermal spraying techniques.

García, E.; Miranzo, P.; Osendi, M. I.

2013-06-01

310

Solution-processed anodes from layer-structure materials for high-efficiency polymer light-emitting diodes.  

UK PubMed Central (United Kingdom)

The development of low-cost, large-area electronic applications requires the deposition of active materials in simple and inexpensive techniques at room temperature, properties usually associated with polymer films. In this study, we demonstrate the integration of solution-processed inorganic films in light-emitting diodes. The layered transition metal dichalcogenide (LTMDC) films are deposited through Li intercalation and exfoliation in aqueous solution and partially oxidized in an oxygen plasma generator. The chemical composition and thickness of the LTMDC and corresponding transition metal oxide (TMO) films are investigated by X-ray photoelectron spectroscopy. The morphology and topography of the films are studied by atomic force microscopy. X-ray powder diffraction is used to determine the orientation of the LTMDC film. Finally, the LTMDC and their corresponding oxides are utilized as hole-injecting and electron-blocking materials in polymer light-emitting diodes with the general structure ITO/LTMDC/TMO/polyfluorene/Ca/Al. Efficient hole injection and electron blocking by the inorganic layers result in outstanding device performance and high efficiency.

Frey GL; Reynolds KJ; Friend RH; Cohen H; Feldman Y

2003-05-01

311

Solution-processed anodes from layer-structure materials for high-efficiency polymer light-emitting diodes.  

Science.gov (United States)

The development of low-cost, large-area electronic applications requires the deposition of active materials in simple and inexpensive techniques at room temperature, properties usually associated with polymer films. In this study, we demonstrate the integration of solution-processed inorganic films in light-emitting diodes. The layered transition metal dichalcogenide (LTMDC) films are deposited through Li intercalation and exfoliation in aqueous solution and partially oxidized in an oxygen plasma generator. The chemical composition and thickness of the LTMDC and corresponding transition metal oxide (TMO) films are investigated by X-ray photoelectron spectroscopy. The morphology and topography of the films are studied by atomic force microscopy. X-ray powder diffraction is used to determine the orientation of the LTMDC film. Finally, the LTMDC and their corresponding oxides are utilized as hole-injecting and electron-blocking materials in polymer light-emitting diodes with the general structure ITO/LTMDC/TMO/polyfluorene/Ca/Al. Efficient hole injection and electron blocking by the inorganic layers result in outstanding device performance and high efficiency. PMID:12733940

Frey, Gitti L; Reynolds, Kieran J; Friend, Richard H; Cohen, Hagai; Feldman, Yishay

2003-05-14

312

Influence of fouling on the efficiency of sacrificial anodes in providing cathodic protection in Southeast Asian tropical seawater.  

Science.gov (United States)

Aluminum and zinc based sacrificial anodes are routinely used to provide corrosion protection to metals (typically steel) exposed to seawater, for example in steel pipelines and storage tanks. However, the high fouling rates experienced in South East Asia means that both the anodes and the metals to be protected rapidly become coated with macrofoulers, which could potentially prevent the anodes from being effective. The present study, involving exposure tests of up to 18 months, indicates that both aluminum and zinc sacrificial anodes remain effective even after being completely coated with biofouling. Furthermore, it was easier to remove the biofouling on the cathodically protected samples than on their unprotected counterparts, possibly due to the higher local pH produced by cathodic protection at the metal and seawater interface. PMID:20818571

Blackwood, D J; Lim, C S; Teo, S L M

2010-10-01

313

Influence of fouling on the efficiency of sacrificial anodes in providing cathodic protection in Southeast Asian tropical seawater.  

UK PubMed Central (United Kingdom)

Aluminum and zinc based sacrificial anodes are routinely used to provide corrosion protection to metals (typically steel) exposed to seawater, for example in steel pipelines and storage tanks. However, the high fouling rates experienced in South East Asia means that both the anodes and the metals to be protected rapidly become coated with macrofoulers, which could potentially prevent the anodes from being effective. The present study, involving exposure tests of up to 18 months, indicates that both aluminum and zinc sacrificial anodes remain effective even after being completely coated with biofouling. Furthermore, it was easier to remove the biofouling on the cathodically protected samples than on their unprotected counterparts, possibly due to the higher local pH produced by cathodic protection at the metal and seawater interface.

Blackwood DJ; Lim CS; Teo SL

2010-10-01

314

Dynamics of polymer molecules with sacrificial bond and hidden length systems: towards a physically-based mesoscopic constitutive law.  

UK PubMed Central (United Kingdom)

We investigate the entropic force-elongation behavior of a polymer chain in the presence of the sacrificial bond and hidden length (SBHL) system observed experimentally in many biomaterials. We show that in most cases the SBHL system leads to a significant increase in toughness. However, the presence of a large number of bonds or relatively strong bonds in the SBHL system can reduce the net gain in toughness. We also incorporate the polymer model into a network of polymers with random properties (e.g., contour length, number and strength of sacrificial bonds, length of hidden loops). This allows us to derive a physically-based mesoscopic force-displacement law that governs the collective behavior.

Elbanna AE; Carlson JM

2013-01-01

315

Impact of Carbon and Tungsten as Divertor Materials on the Scrape-off Layer Conditions in JET  

International Nuclear Information System (INIS)

[en] Full text: In detached divertor conditions, a five-fold stronger reduction of the ion current to the low-field side target plate and a 30% increase in the density limit were observed in neutral-beam heated, low-confinement mode plasmas with the ITER-like Wall compared to the previous carbon wall. These significant differences occurred at higher core densities despite the fact that nearly identical scrape-off layer parameters were measured in attached divertor conditions. When attached, the magnitude and distribution of radiative power as well as the total ion currents to the divertor target plates were measured the same for a range of divertor plasma geometries, including configurations with the high field side strike point on the vertical plate and the low field side strike point on the horizontal plate, and configurations with both strike points on the vertical plates. The 5-to-10-fold reduction of the scrape-off layer carbon content as inferred from low charge state carbon emission, and the fact that both beryllium and tungsten have a low radiation potential in the scrape-off layer, would indicate that the deuterium emission was and still is the dominating radiator. Simulations of deuterium gas fuelling scans with the fluid edge code EDGE2/EIRENE show that replacing carbon with beryllium and tungsten as wall materials leads to reduced impurity radiation, as expected, and translates into an increase in the power conducted to the plates. The ion currents to the plates, however, are predicted to be similar in both materials configurations. Saturation of the ion currents is predicted at the highest achievable density; the simulations do not predict the reduction of the currents close to the density limit as observed in the experiments. Since the JET ITER-like wall constitutes the same materials and their poloidal distribution as foreseen for the nuclear phase of ITER, understanding the observed differences in the SOL conditions between the two materials configuration, and clarifying the discrepancy between the experimental data and simulations are instrumental for erosion and power handling in ITER. (author)

2012-01-01

316

Quantitative evaluation of ultrasonic C-scan image in acoustically homogeneous and layered anisotropic materials using three dimensional ray tracing method.  

UK PubMed Central (United Kingdom)

Quantitative evaluation of ultrasonic C-scan images in homogeneous and layered anisotropic austenitic materials is of general importance for understanding the influence of anisotropy on wave fields during ultrasonic non-destructive testing and evaluation of these materials. In this contribution, a three dimensional ray tracing method is presented for evaluating ultrasonic C-scan images quantitatively in general homogeneous and layered anisotropic austenitic materials. The directivity of the ultrasonic ray source in general homogeneous columnar grained anisotropic austenitic steel material (including layback orientation) is obtained in three dimensions based on Lamb's reciprocity theorem. As a prerequisite for ray tracing model, the problem of ultrasonic ray energy reflection and transmission coefficients at an interface between (a) isotropic base material and anisotropic austenitic weld material (including layback orientation), (b) two adjacent anisotropic weld metals and (c) anisotropic weld metal and isotropic base material is solved in three dimensions. The influence of columnar grain orientation and layback orientation on ultrasonic C-scan image is quantitatively analyzed in the context of ultrasonic testing of homogeneous and layered austenitic steel materials. The presented quantitative results provide valuable information during ultrasonic characterization of homogeneous and layered anisotropic austenitic steel materials.

Kolkoori S; Hoehne C; Prager J; Rethmeier M; Kreutzbruck M

2013-08-01

317

Carbon aerogels as electrode material for electrical double layer supercapacitors-Synthesis and properties  

International Nuclear Information System (INIS)

This paper constitutes a description of technological research the aim of which was to design a symmetric supercapacitor dedicated for the system of quality of electrical energy improvement (supply interruption, voltage dip). The main task was to use the carbon aerogel technology as the efficient method for production of electrode material with desirable properties. Carbon aerogels were prepared by carbonization of resorcinol-formaldehyde (RF) polymer gels. RF-gels were synthesized by curing polycondensation and by the inverse emulsion polymerization of resorcinol with formaldehyde, followed by microwave drying. The morphostructural characteristics of the carbon aerogels were investigated by atomic force microscopy (AFM) and the N2 adsorption (BET method). The electrochemical properties were characterized by means of cycle voltammetry, galvanostatic charging/discharging, and self-discharge.

2010-10-30

318

Deoxyguanosine phosphate mediated sacrificial bonds promote synergistic mechanical properties in nacre-mimetic nanocomposites.  

UK PubMed Central (United Kingdom)

We show that functionalizing polymer-coated colloidal nanoplatelets with guanosine groups allows synergistic increase of mechanical properties in nacre-mimetic lamellar self-assemblies. Anionic montmorillonite (MTM) was first coated using cationic poly(diallyldimethylammonium chloride) (PDADMAC) to prepare core-shell colloidal platelets, and subsequently the remaining chloride counterions allowed exchange to functional anionic 2'-deoxyguanosine 5'-monophosphate (dGMP) counterions, containing hydrogen bonding donors and acceptors. The compositions were studied using elemental analysis, scanning and transmission electron microscopy, wide-angle X-ray scattering, and tensile testing. The lamellar spacing between the clays increases from 1.85 to 2.14 nm upon addition of the dGMP. Adding dGMP increases the elastic modulus, tensile strength, and strain 33.0%, 40.9%, and 5.6%, respectively, to 13.5 GPa, 67 MPa, and 1.24%, at 50% relative humidity. This leads to an improved toughness seen as a ca. 50% increase of the work-to-failure. This is noteworthy, as previously it has been observed that connecting the core-shell nanoclay platelets covalently or ionically leads to increase of the stiffness but to reduced strain. We suggest that the dynamic supramolecular bonds allow slippage and sacrificial bonds between the self-assembling nanoplatelets, thus promoting toughness, still providing dynamic interactions between the platelets.

Martikainen L; Walther A; Seitsonen J; Berglund L; Ikkala O

2013-08-01

319

Electrochemical treatment of Orange II dye solution-Use of aluminum sacrificial electrodes and floc characterization  

International Nuclear Information System (INIS)

Electrocoagulation (EC) of Orange II dye in a flow through cell with aluminum as sacrificial electrodes was carried out under varying conditions of dye concentration, current density, flow rate, conductivity, and the initial pH of the solution in order to optimize the operating parameters for maximum benefits. Maximum removal efficiency of 94.5% was obtained at the following conditions: dye concentration = 10 ppm, current density = 160 A/m2, initial pH 6.5, conductance = 7.1 mS/cm, flow rate = 350 mL/min, and concentration of added NaCl = 4.0 g/L of dye solution. The EC-floc was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive X-ray spectroscopy, and powder X-ray diffraction techniques. The removal mechanism has been proposed that is in compliance with the Pourbaix diagram, solubility curve of aluminum oxides/hydroxides, and physico-chemical properties of the EC-floc.

2010-02-15

320

Hierarchical assembly of Ti(iv)/Sn(ii) co-doped SnO2 nanosheets along sacrificial titanate nanowires: synthesis, characterization and electrochemical properties.  

UK PubMed Central (United Kingdom)

Hierarchical assembly of Ti(iv)/Sn(ii)-doped SnO2 nanosheets along titanate nanowires serving as both sacrificial templates and a Ti(iv) source is demonstrated, using SnCl2 as a tin precursor and Sn(ii) dopants and NaF as the morphology controlling agent. Excess fluoride inhibits the hydrolysis of SnCl2, promoting heterogeneous nucleation of Sn(ii)-doped SnO2 on the titanate nanowires due to the insufficient oxidization of Sn(ii) to Sn(iv). Simultaneously, titanate nanowires are dissolved forming Ti(4+) species under the etching effect of in situ generated HF resulting in spontaneous Ti(4+) ion doping of SnO2 nanosheets formed under hydrothermal conditions. Compositional analysis indicates that Ti(4+) ions are incorporated by substitution of Sn sites at a high level (16-18 at.%), with uniform distribution and no phase separation. Mössbauer spectroscopy quantified the relative content of Sn(ii) and Sn(iv) in both Sn(ii)-doped and Ti(iv)/Sn(ii) co-doped SnO2 samples. Electrochemical properties were investigated as an anode material in lithium ion batteries, demonstrating that Ti-doped SnO2 nanosheets show improved cycle performance, which is attributed to the alleviation of inherent volume expansion of the SnO2-based anode materials by substituting part of Sn sites with Ti dopants.

Wang H; Xi L; Tucek J; Zhan Y; Hung TF; Kershaw SV; Zboril R; Chung CY; Rogach AL

2013-08-01

 
 
 
 
321

Hierarchical assembly of Ti(iv)/Sn(ii) co-doped SnO2 nanosheets along sacrificial titanate nanowires: synthesis, characterization and electrochemical properties.  

UK PubMed Central (United Kingdom)

Hierarchical assembly of Ti(iv)/Sn(ii)-doped SnO2 nanosheets along titanate nanowires serving as both sacrificial templates and a Ti(iv) source is demonstrated, using SnCl2 as a tin precursor and Sn(ii) dopants and NaF as the morphology controlling agent. Excess fluoride inhibits the hydrolysis of SnCl2, promoting heterogeneous nucleation of Sn(ii)-doped SnO2 on the titanate nanowires due to the insufficient oxidization of Sn(ii) to Sn(iv). Simultaneously, titanate nanowires are dissolved forming Ti(4+) species under the etching effect of in situ generated HF resulting in spontaneous Ti(4+) ion doping of SnO2 nanosheets formed under hydrothermal conditions. Compositional analysis indicates that Ti(4+) ions are incorporated by substitution of Sn sites at a high level (16-18 at.%), with uniform distribution and no phase separation. Mössbauer spectroscopy quantified the relative content of Sn(ii) and Sn(iv) in both Sn(ii)-doped and Ti(iv)/Sn(ii) co-doped SnO2 samples. Electrochemical properties were investigated as an anode material in lithium ion batteries, demonstrating that Ti-doped SnO2 nanosheets show improved cycle performance, which is attributed to the alleviation of inherent volume expansion of the SnO2-based anode materials by substituting part of Sn sites with Ti dopants.

Wang H; Xi L; Tucek J; Zhan Y; Hung TF; Kershaw SV; Zboril R; Chung CY; Rogach AL

2013-10-01

322

Development of bipolar plates for fuel cells from graphite filled wet-lay material and a thermoplastic laminate skin layer  

Energy Technology Data Exchange (ETDEWEB)

In this paper, a method with the potential to rapidly produce thermoplastic polymer composite bipolar plates with improved formability and through-plane conductivity is described. In our earlier work, it was reported that composite bipolar plates made with graphite filled wet-lay materials exhibited excellent mechanical properties and in-plane electrical conductivity. However, the through-plane conductivity and formability of the materials needed improvement. In this work, laminate polymer composite plates consisting of a wet-lay based core and a fluoropolymer/graphite skin layer are manufactured in an effort to improve formability and through-plane conductivity. These plates are characterized by their through-plane and in-plane conductivity, half-cell resistance, and mechanical properties at ambient and elevated temperatures. The laminate plates with PPS based wet-lay core exhibited bulk conductivities of above 300 S cm{sup -1}, tensile strength of up to 34 MPa, and flexural strength of up to 54 MPa. Compared to the bipolar plates consisting of wet-lay material only, the bipolar plates with laminate structure exhibited an increase in through-plane conductivity of 25-35%, as well as a decrease in half-cell resistance by a factor of up to 5. The laminate bipolar plates can be manufactured in several ways with two of them being discussed in detail in the paper. (author)

Cunningham, Brent D.; Huang, Jianhua; Baird, Donald G. [Chemical Engineering and Macromolecules and Interfaces Institute Virginia Tech, Blacksburg, VA 24061 (United States)

2007-03-20

323

Empirical force fields for complex hydrated calcio-silicate layered materials.  

UK PubMed Central (United Kingdom)

The use of empirical force fields is now a standard approach in predicting the properties of hydrated oxides which are omnipresent in both natural and engineering applications. Transferability of force fields to analogous hydrated oxides without rigorous investigations may result in misleading property predictions. Herein, we focus on two common empirical force fields, the simple point charge ClayFF potential and the core-shell potential to study tobermorite minerals, the most prominent family of Calcium-Silicate-Hydrates that are complex hydrated oxides. We benchmark the predictive capabilities of these force fields against first principles results. While the structural information seem to be in close agreement with DFT results, we find that for higher order properties such as elastic constants, the core-shell potential quantitatively improves upon the simple point charge model, and shows a larger degree of transferability to complex materials. In return, to remedy the deficiencies of the simple point charge potential for hydrated calcio-silicates, we suggest using both structural data and elasticity data for potential calibration, a new force field potential, CSH-FF. This re-parameterized version of ClayFF is then applied to simulating an atomistic model of cement (Pellenq et al., PNAS, 2009). We demonstrate that this force field improves the predictive capabilities of ClayFF, being considerably less computational intensive than the core-shell model.

Shahsavari R; Pellenq RJ; Ulm FJ

2011-01-01

324

Zirconia layer coated mesoporous silica microspheres as HILIC SPE materials for selective glycopeptide enrichment.  

Science.gov (United States)

Characterization of protein glycosylation requires highly specific methods for the enrichment of glycopeptides because of their sub-stoichiometric glycosylation-site occupancy. The hydrophilic affinity based strategy has attracted more attention, owing to its broad glycan specificity, good reproducibility, and compatibility with mass spectrometric (MS) analysis. Several polar matrices have emerged for hydrophilic interaction chromatography (HILIC) approaches, including sepharose, cellulose, ZIC-HILIC and titania. Here, we present the solid-phase extraction (SPE) utility of zirconia coated mesoporous silica (ZrO(2)/MPS) microspheres for glycopeptide isolation prior to MS analysis. The high specificity of this SPE approach was demonstrated by the enrichment of glycopeptides from the digests of model glycoproteins in HILIC mode. ZrO(2)/MPS microspheres show superior selectivity and glycosylation heterogeneity coverage for glycopeptide enrichment to conventional sepharose. Furthermore, digested mixtures of the phosphoprotein ?-casein and IgG were also treated with ZrO(2)/MPS HILIC SPE materials, which exhibited that glycopeptides could be effectively enriched with interference from phosphorylated peptides. PMID:21897947

Wan, Huihui; Yan, Jingyu; Yu, Long; Sheng, Qianying; Zhang, Xiuli; Xue, Xingya; Li, Xiuling; Liang, Xinmiao

2011-09-07

325

Zirconia layer coated mesoporous silica microspheres as HILIC SPE materials for selective glycopeptide enrichment.  

UK PubMed Central (United Kingdom)

Characterization of protein glycosylation requires highly specific methods for the enrichment of glycopeptides because of their sub-stoichiometric glycosylation-site occupancy. The hydrophilic affinity based strategy has attracted more attention, owing to its broad glycan specificity, good reproducibility, and compatibility with mass spectrometric (MS) analysis. Several polar matrices have emerged for hydrophilic interaction chromatography (HILIC) approaches, including sepharose, cellulose, ZIC-HILIC and titania. Here, we present the solid-phase extraction (SPE) utility of zirconia coated mesoporous silica (ZrO(2)/MPS) microspheres for glycopeptide isolation prior to MS analysis. The high specificity of this SPE approach was demonstrated by the enrichment of glycopeptides from the digests of model glycoproteins in HILIC mode. ZrO(2)/MPS microspheres show superior selectivity and glycosylation heterogeneity coverage for glycopeptide enrichment to conventional sepharose. Furthermore, digested mixtures of the phosphoprotein ?-casein and IgG were also treated with ZrO(2)/MPS HILIC SPE materials, which exhibited that glycopeptides could be effectively enriched with interference from phosphorylated peptides.

Wan H; Yan J; Yu L; Sheng Q; Zhang X; Xue X; Li X; Liang X

2011-11-01

326

Controllable synthesis of graphene sheets with different numbers of layers and effect of the number of graphene layers on the specific capacity of anode material in lithium-ion batteries  

International Nuclear Information System (INIS)

[en] High quality graphene sheets are synthesized through efficient oxidation process followed by rapid thermal expansion and reduction by H2. The number of graphene layers is controlled by tuning the oxidation degree of GOs. The higher the oxidation degree of GOs is getting, the fewer the numbers of graphene layers can be obtained. The material is characterized by elemental analysis, thermo-gravimetric analysis, scanning electron microscopy, atomic force microscopy, transmission electron microscopy and Fourier transform infrared spectroscopies. The obtained graphene sheets with single, triple and quintuplicate layers as anode materials exhibit a high reversible capacity of 1175, 1007, and 842 mA h g-1, respectively, which show that the graphene sheets with fewer layers have higher reversible capacity. -- Graphical abstract: The typical TEM images of the graphene sheets derived from GO3(a), GO2(b) and GO1(c). Display Omitted Highlights: ? With the oxidation degree of GO increasing, the numbers of graphene layers decreased. ? With the numbers of graphene layers decreasing, the reversible capacity improved. ? Graphene sheets with single-layer exhibit the best electrochemical performances.

2011-01-01

327

Mechanically stacked 1 nm thick carbon nanosheets: Ultrathin layered materials with tunable optical, chemical and electrical properties  

CERN Multimedia

Carbon nanosheets are mechanically stable free-standing two-dimensional materials with a thickness of ~1 nm and well defined physical and chemical properties. They are made by radiation induced cross-linking of aromatic self-assembled monolayers. Here we present a route to the scalable fabrication of multilayer nanosheets with tunable electrical, optical and chemical properties on insulating substrates. Stacks up to five nanosheets with sizes of ~1 cm^2 on oxidized silicon were studied. Their optical characteristics were investigated by visual inspection, optical microscopy, UV/Vis reflection spectroscopy and model calculations. Their chemical composition was studied by X-ray photoelectron spectroscopy. The multilayer samples were then annealed in ultra high vacuum at various temperatures up to 1100 K. A subsequent investigation by Raman, X-ray photoelectron and UV/Vis reflection spectroscopy as well as by electrical four-point probe measurements demonstrates that the layered nanosheets transform into nanocry...

Nottbohm, Christoph T; Beyer, Andre; Stosch, Rainer; Golzhauser, Armin; 10.1002/smll.201001993

2011-01-01

328

Effect of initial stress on Love waves in a piezoelectric structure carrying a functionally graded material layer.  

UK PubMed Central (United Kingdom)

The effect of initial stress on the propagation behavior of Love waves in a piezoelectric half-space of polarized ceramics carrying a functionally graded material (FGM) layer is analytically investigated in this paper from the three-dimensional equations of linear piezoelectricity. The analytical solutions are obtained for the dispersion relations of Love wave propagating in this kind of structure with initial stress for both electrical open case and electrical short case, respectively. One numerical example is given to graphically illustrate the effect of initial stress on dispersive curve, phase velocity and electromechanical coupling factor of the Love wave propagation. The results reported here are meaningful for the design of surface acoustic wave (SAW) devices with high performance.

Qian ZH; Jin F; Lu T; Kishimoto K; Hirose S

2010-01-01

329

Effect of initial stress on Love waves in a piezoelectric structure carrying a functionally graded material layer.  

Science.gov (United States)

The effect of initial stress on the propagation behavior of Love waves in a piezoelectric half-space of polarized ceramics carrying a functionally graded material (FGM) layer is analytically investigated in this paper from the three-dimensional equations of linear piezoelectricity. The analytical solutions are obtained for the dispersion relations of Love wave propagating in this kind of structure with initial stress for both electrical open case and electrical short case, respectively. One numerical example is given to graphically illustrate the effect of initial stress on dispersive curve, phase velocity and electromechanical coupling factor of the Love wave propagation. The results reported here are meaningful for the design of surface acoustic wave (SAW) devices with high performance. PMID:19828172

Qian, Zheng-Hua; Jin, Feng; Lu, Tianjian; Kishimoto, Kikuo; Hirose, Sohichi

2009-08-23

330

Measuring Lamb wave dispersion curves of a bi-layered plate and its application on material characterization of coating.  

Science.gov (United States)

This paper investigates the Lamb wave dispersion curves of a bi-layered plate and evaluates the feasibility of using the dispersion data to characterize the coating's material properties. The measurement of dispersion curves is based on a focusing PVDF transducer operating in a pulse/echo mode. An image displaying technique is used to determine the dispersion relation of Lamb waves from the measured data. Multiple dispersion curves of Lamb waves are accurately determined over a wide frequency range (4 to 20 MHz). Lamb wave dispersion curves for thin metal sheets electro-deposited with nickel coatings are measured. The elastic constants of the nickel coating are determined by comparing the experimental dispersion data with the theoretical ones calculated numerically. Potential applications of this measurement method are addressed. PMID:11381708

Lee, Y C; Cheng, S W

2001-05-01

331

Measuring Lamb wave dispersion curves of a bi-layered plate and its application on material characterization of coating.  

UK PubMed Central (United Kingdom)

This paper investigates the Lamb wave dispersion curves of a bi-layered plate and evaluates the feasibility of using the dispersion data to characterize the coating's material properties. The measurement of dispersion curves is based on a focusing PVDF transducer operating in a pulse/echo mode. An image displaying technique is used to determine the dispersion relation of Lamb waves from the measured data. Multiple dispersion curves of Lamb waves are accurately determined over a wide frequency range (4 to 20 MHz). Lamb wave dispersion curves for thin metal sheets electro-deposited with nickel coatings are measured. The elastic constants of the nickel coating are determined by comparing the experimental dispersion data with the theoretical ones calculated numerically. Potential applications of this measurement method are addressed.

Lee YC; Cheng SW

2001-05-01

332

Deposition of thin films of organic-inorganic hybrid materials based on aromatic carboxylic acids by atomic layer deposition.  

UK PubMed Central (United Kingdom)

Thin films of organic-inorganic hybrid materials have been grown by the atomic layer deposition (ALD) technique, using trimethylaluminium (TMA) and aromatic carboxylic acids such as 1,2-benzene dicarboxylic acid, 1,3-benzene dicarboxylic acid, 1,4-benzene dicarboxylic acid, 1,3,5-benzene tricarboxylic acid, 1,2,4,5-benzene tetracarboxylic acid as precursors. Growth rates as function of temperature show that all systems, with the exception of the benzoic acid-TMA system, possess ALD-windows and provides growth rates in the range of 0.25-1.34 nm/cycle. X-ray diffraction studies of the as-deposited films reveal their amorphous character, which is also supported by very low surface roughness as measured by atomic force microscopy. As-deposited films were investigated by Fourier Transform Infrared Spectroscopy proving that the deposited films are of a hybrid character.

Klepper KB; Nilsen O; Fjellvåg H

2010-12-01

333

Flaw detection in a multi-material multi-layered composite: using fem and air-coupled ut  

International Nuclear Information System (INIS)

Ceramic tiles are the main ingredient of a multi-layer multi-material composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. This study is aimed at modeling the vibration modes of the tiles and the composite lay-up with finite element analysis and comparing the results with the resonance modes observed in air-coupled ultrasonic excitation of the tiles and armor samples. Defects in the tile, during manufacturing and/or after usage, are expected to change the resonance modes. The comparison of a pristine tile/lay-up and a defective tile/lay-up will thus be a quantitative damage metric. The understanding of the vibration behavior of the tile, both by itself and in the composite lay-up, can provide useful guidance to the nondestructive evaluation of armor panels containing ceramic tiles.

2011-06-23

334

Flaw Detection in a Multi-Material Multi-Layered Composite: Using FEM and Air-Coupled UT  

Science.gov (United States)

Ceramic tiles are the main ingredient of a multi-layer multi-material composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. This study is aimed at modeling the vibration modes of the tiles and the composite lay-up with finite element analysis and comparing the results with the resonance modes observed in air-coupled ultrasonic excitation of the tiles and armor samples. Defects in the tile, during manufacturing and/or after usage, are expected to change the resonance modes. The comparison of a pristine tile/lay-up and a defective tile/lay-up will thus be a quantitative damage metric. The understanding of the vibration behavior of the tile, both by itself and in the composite lay-up, can provide useful guidance to the nondestructive evaluation of armor panels containing ceramic tiles.

Livings, R. A.; Dayal, V.; Barnard, D. J.; Hsu, D. K.

2011-06-01

335

Anion-exchangeable layered materials based on rare-earth phosphors: unique combination of rare-earth host and exchangeable anions.  

UK PubMed Central (United Kingdom)

Layered materials, three-dimensional crystals built from stacking two-dimensional components, are attracting intense interest because of their structural anisotropy and the fascinating properties that result. However, the range of such layered materials that can exchange anions is quite small. Continuing efforts have been underway to identify a new class of anion-exchangeable materials. One major goal is the incorporation of rare-earth elements within the host because researchers expect that the marriage of rare-earth skeleton host and the exchangeable species within the interlayer will open up new avenues both for the assembly of layered materials and for the understanding of rare-earth element chemistry. Such lanthanide layered solids have industrial potential. These materials are also of academic importance, serving as an ideal model for studying the cationic size effect on structure stability associated with lanthanide contraction. In this Account, we present the work done by ourselves and others on this novel class of materials. We examine the following four subtopics regarding these layered anionic materials: (1) synthesis strategy and composition diversity, (2) structural features, (3) structure stability with relative humidity, and (4) applications. These materials can be synthesized either by hydrothermal reactions or by homogeneous precipitation, and a variety of anions can be intercalated into the gallery. Although only cations with a suitable size can form the layered structure, the possible range is wide, from early to late lanthanides. We illustrate the effect of lanthanide contraction on properties including morphology, lattice dimensions, and coordination numbers. Because each lanthanide metal ion coordinates water molecules, and the water molecules point directly into the gallery space, this feature plays a critical role in stabilizing the layered structure. In the 9-fold monocapped square antiprism structure, the humidity-triggered transition between high- and low-hydrated phases corresponds to the uptake of H(2)O molecules at the capping site, which provides further evidence of the importance of water coordination. Applications using this unique combination of rare-earth element chemistry and layered materials include ion-exchange, photoluminescence, catalysis, and biomedical devices. Further exploration of the compounds and new methods for functional modification would dramatically enrich the junction of these two fields, leading to a new generation of layered materials with desirable properties.

Geng F; Ma R; Sasaki T

2010-09-01

336

Near-field imaging by a multi-layer structure consisting of alternate right-handed and left-handed materials  

International Nuclear Information System (INIS)

The possibility of near-field imaging by a multi-layer structure with alternate layers of right-handed materials (RHM) and left-handed materials (LHM) is investigated. By means of the transfer-matrix method, we carry out the recovery rate and phase shift of evanescent waves arriving at the image plane. It is found that the multi-layer structure is very useful to decrease the influence of the necessary absorption in left-handed materials (LHM) on the image quality. We also show that the absorption may be useful to enhance the image quality when the real parts of the permittivity and permeability of left-handed materials (LHM) deviates from the perfect lens conditions

2004-03-08

337

Metal-gate/high-k dielectric stack engineering by atomic layer deposition: Materials issues and electrical properties  

Science.gov (United States)

Scaling of silicon devices beyond the 65nm node requires the replacement of poly-Si/SiO2 gate stack with a metal gate/high-k dielectric stack that can potentially reduce the off-state leakage current without compromising device performance. In this study, we have evaluated HfO2 as the gate dielectric material and TaN as the metal gate electrode deposited using the Atomic Layer Deposition (ALD) technique. ALD provides us with the unique capability of growing high quality thin films with excellent control over the film thickness, stoichiometry and conformality. Nanoscale HfO2 films were deposited by ALD on Si substrates using two different precursor chemistries---HfCl4 and Tetrakis (Diethylamido) Hafnium (TDEAH) with H2O as the oxidant. A systematic study of the physical and electrical properties of the HfO2 films derived using the two different chemistries revealed that the magnitude and sign of the fixed charge in the dielectric varied depending on the precursor used for the deposition. Our results indicate that Cl impurities, left behind by the HfCl4 precursor during deposition, significantly impact the electrical properties of the chloride-HfO 2. Tantalum nitride thin films were deposited by a remote plasma-enhanced ALD (PEALD) method using a novel metal organic precursor---isopropylimino tris(ethylmethylamino) tantalum (IPTEMT). It was identified that the as-deposited tantalum nitride film was the dielectric Ta3N5 phase. High temperature in-situ anneals performed in the TEM column crystallized the ALD tantalum nitride film at 850°C into the stoichiometric cubic TaN phase. The phase transformation from dielectric Ta3N5 to metallic TaN is achieved by out-diffusion of excess nitrogen atoms from the Ta3N5 film during the high temperature anneal. TaN was evaluated as a potential gate electrode material both on SiO2 and HfO2 gate dielectrics. The impact of high temperature anneals on the mobility of hydroxyl and oxygen impurities in the stack and its effect on the thickness of the interfacial layer was studied in detail. A novel low temperature process was identified to engineer the TaN/HfO2 gate stack using a reactive titanium metal overlayer to getter the excess nitrogen from Ta3N5.

Sreenivasan, Raghavasimhan

338

Impact of carbon and tungsten as divertor materials on the scrape-off layer conditions in JET  

Science.gov (United States)

The impact of carbon and beryllium/tungsten as plasma-facing components on plasma radiation, divertor power and particle fluxes, and plasma and neutral conditions in the divertors has been assessed in JET both experimentally and by edge fluid code simulations for plasmas in low-confinement mode. In high-recycling conditions the studies show a 30% reduction in total radiation in the scrape-off (SOL) layer when replacing carbon (JET-C) with beryllium in the main chamber and tungsten in the divertor (JET-ILW). Correspondingly, at the low-field side (LFS) divertor plate a two-fold increase in power conducted to the plate and a two-fold increase in electron temperature at the strike point were measured. In low-recycling conditions the SOL was found to be nearly identical for both materials' configurations. Saturation and rollover of the ion currents to both low- and high-field side (HFS) plates was measured to occur at 30% higher upstream densities and radiated power fraction in JET-ILW. Past saturation, it was possible to reduce the ion currents to the LFS targets by a factor of 2 and to continue operating in stable, detached conditions in JET-ILW; in JET-C the reduction was limited to 50%. These observations are in qualitative agreement with predictions from the fluid edge code package EDGE2D/EIRENE, for which a 30% reduction of the total radiated power is also yielded when switching from C to Be/W. For matching upstream parameters the magnitude of predicted radiation is, however, 50% to 100% lower than measured, independent of the materials' configuration. Inclusion of deuterium molecules and molecular ions, and temperature and density dependent rates in EIRENE reproduced the experimentally observed rollover of the ion current to the LFS plate, via reducing the electron temperature at the plate.

Groth, M.; Brezinsek, S.; Belo, P.; Beurskens, M. N. A.; Brix, M.; Clever, M.; Coenen, J. W.; Corrigan, C.; Eich, T.; Flanagan, J.; Guillemaut, C.; Giroud, C.; Harting, D.; Huber, A.; Jachmich, S.; Kruezi, U.; Lawson, K. D.; Lehnen, M.; Lowry, C.; Maggi, C. F.; Marsen, S.; Meigs, A. G.; Pitts, R. A.; Sergienko, G.; Sieglin, B.; Silva, C.; Sirinelli, A.; Stamp, M. F.; van Rooij, G. J.; Wiesen, S.; JET-EFDA Contributors, the

2013-09-01

339

Hollow microneedles for intradermal injection fabricated by sacrificial micromolding and selective electrodeposition.  

UK PubMed Central (United Kingdom)

Limitations with standard intradermal injections have created a clinical need for an alternative, low-cost injection device. In this study, we designed a hollow metal microneedle for reliable intradermal injection and developed a high-throughput micromolding process to produce metal microneedles with complex geometries. To fabricate the microneedles, we laser-ablated a 70 ?m × 70 ?m square cavity near the tip of poly(lactic acid) (PLA) microneedles. The master structure was a template for multiple micromolded poly(lactic acid-co-glycolic acid) (PLGA) replicas. Each replica was sputtered with a gold seed layer with minimal gold deposited in the cavity due to masking effects. In this way, nickel was electrodeposited selectively outside of the cavity, after which the polymer replica was dissolved to produce a hollow metal microneedle. Force-displacement tests showed the microneedles, with 12 ?m thick electrodeposition, could penetrate skin with an insertion force 9 times less than their axial failure force. We injected fluid with the microneedles into pig skin in vitro and hairless guinea pig skin in vivo. The injections targeted 90 % of the material within the skin with minimal leakage onto the skin surface. We conclude that hollow microneedles made by this simple microfabrication method can achieve targeted intradermal injection.

Norman JJ; Choi SO; Tong NT; Aiyar AR; Patel SR; Prausnitz MR; Allen MG

2013-04-01

340

Improving the fluorescence polarization method to evaluate the orientation of fluorescent systems adsorbed in ordered layered materials  

Energy Technology Data Exchange (ETDEWEB)

The fluorescence polarization method, recently developed for the evaluation of the preferential orientation of fluorescent dyes adsorbed in layered materials [F. Lopez Arbeloa, V. Martinez Martinez, J. Photochem. Photobiol. A: Chem. 181 (2006) 44], is readapted to improve its application. Fluorescence polarization was previously obtained by recording the emission intensity for two orthogonal orientations of the emission polarizer (i.e., the horizontal and vertical polarized light) after excitation with vertical or horizontal polarized light. In the method proposed in this work, samples are excited with unpolarized light, reducing the polarization effect of the excitation light scattering at those emission wavelengths close to the excitation wavelength. Moreover, the present method decreases the effect of the orientation of other non-fluorescent species present in the system, which are active in the excitation process. Consequently, the new method is more simple, precise and sensitive. It is applied to evaluate the orientation of rhodamine 6G dye adsorbed in ordered laponite clay films with low and moderated dye loadings.

Salleres, Sandra [Departamento de Quimica Fisica, Universidad del Pais Vasco UPV/EHU, Apartado 644, 48080 Bilbao (Spain); Arbeloa, Fernando Lopez, E-mail: fernando.lopezarbeloa@ehu.e [Departamento de Quimica Fisica, Universidad del Pais Vasco UPV/EHU, Apartado 644, 48080 Bilbao (Spain); Martinez, Virginia Martinez; Arbeloa, Teresa; Lopez Arbeloa, Inigo [Departamento de Quimica Fisica, Universidad del Pais Vasco UPV/EHU, Apartado 644, 48080 Bilbao (Spain)

2009-11-15

 
 
 
 
341

Improving the fluorescence polarization method to evaluate the orientation of fluorescent systems adsorbed in ordered layered materials  

International Nuclear Information System (INIS)

The fluorescence polarization method, recently developed for the evaluation of the preferential orientation of fluorescent dyes adsorbed in layered materials [F. Lopez Arbeloa, V. Martinez Martinez, J. Photochem. Photobiol. A: Chem. 181 (2006) 44], is readapted to improve its application. Fluorescence polarization was previously obtained by recording the emission intensity for two orthogonal orientations of the emission polarizer (i.e., the horizontal and vertical polarized light) after excitation with vertical or horizontal polarized light. In the method proposed in this work, samples are excited with unpolarized light, reducing the polarization effect of the excitation light scattering at those emission wavelengths close to the excitation wavelength. Moreover, the present method decreases the effect of the orientation of other non-fluorescent species present in the system, which are active in the excitation process. Consequently, the new method is more simple, precise and sensitive. It is applied to evaluate the orientation of rhodamine 6G dye adsorbed in ordered laponite clay films with low and moderated dye loadings.

2009-01-01

342

Comparison of the effect of PLT and PZT buffer layers on PZT thin films for ferroelectric materials applications  

Science.gov (United States)

In order to study the effect of different buffer layers on the Pb(Zr0.52Ti0.48)O3 (PZT) thin films, 10-nm thick (Pb0.72La0.28)Ti0.93O3 (PLT) and Pb(Zr0.52Ti0.48)O3 buffer layers have been deposited on the Pt(1 1 1)/Ti/SiO2/Si substrates by pulsed laser deposition, respectively. The top buffer layers were also deposited on PZT thin films with the same thickness of the seed layers in order to enhance the fatigue characteristics of PZT thin films. We compared the results of dielectric constant, hysteresis loops and fatigue resistance characteristics. It was found that the dielectric properties of PZT thin films with PLT buffer layers were improved by comparing with PZT thin films with PZT buffer layers. The polarization characteristics of PZT thin films with PLT buffer layers were observed to be superior to those of PZT thin films using PZT buffer layers. The remanent polarization of PZT thin films showed 36.3 ?C/cm2 and 2.6 ?C/cm2 each in the case of use PLT and PZT buffer layers. For the switching polarization endurance analysis, PZT thin films with PLT buffer layers showed more excellent result than that of PZT thin films with PZT buffer layers.

Li, Dong Hua; Lee, Eun Sun; Chung, Hyun Woo; Lee, Sang Yeol

2006-04-01

343

Producing flange cap useful for container for holding pharmaceutical substance, comprises molding a material strip exhibiting a pre-plastic-coated film layer to flanged cap by punching and deep drawing  

UK PubMed Central (United Kingdom)

Producing a flange cap comprising a metallic film layer (1), which is covered at the outer side with a plastic layer forming a coating of the film layer, comprises molding a material strip exhibiting a pre-plastic-coated film layer to the flanged cap by punching and deep drawing. Independent claims are also included for: (1) the flange cap comprising the metallic film layer, the plastic layer forming the coating of the film layer, and an additional flange cap-marginal edge (11), where the flange cap-marginal edge exhibits a cutting edge passing through both the film layer and the plastic layer (2, 3), and the flange cap-marginal edge is covered by a portion of the plastic layer, which is stretched compared to the plastic layer and (2) the container comprising the pharmaceutical substance, preferably ampoule, where the container is closed with the flange cap and the flange cap exhibits the metallic film layer.

344

Low-Thermal-Conductivity (MS)1+x(TiS2)2 (M = Pb, Bi, Sn) Misfit Layer Compounds for Bulk Thermoelectric Materials  

Directory of Open Access Journals (Sweden)

Full Text Available A series of (MS)1+x(TiS2)2 (M = Pb, Bi, Sn) misfit layer compounds are proposed as bulk thermoelectric materials. They are composed of alternating rock-salt-type MS layers and paired trigonal anti-prismatic TiS2 layers with a van der Waals gap. This naturally modulated structure shows low lattice thermal conductivity close to or even lower than the predicted minimum thermal conductivity. Measurement of sound velocities shows that the ultra-low thermal conductivity partially originates from the softening of the transverse modes of lattice wave due to weak interlayer bonding. Combined with a high power factor, the misfit layer compounds show a relatively high ZT value of 0.28~0.37 at 700 K.

Chunlei Wan; Yifeng Wang; Ning Wang; Kunihito Koumoto

2010-01-01

345

Preparation of layered Sr{sub 2}CuO{sup 3+{delta}} by pulsed laser deposition. Rational synthesis and doping of a metastable copper oxide material  

Energy Technology Data Exchange (ETDEWEB)

Herein we describe the first synthesis of the layered copper oxide material Sr{sub 2}CuO{sub 3+{delta}} carried out under low-pressure and low-temperature conditions. Reaction under these mild conditions was achieved using the pulsed laser ablation and deposition (PLD) technique. Structural analyses demonstrate that Sr{sub 2}CuO{sub 3+{delta}} prepared by PLD adopts a layered tetragonal structure with a repeat unit consisting of a CuO{sub 2} plane and two SrO{sub {delta}} layers. Investigations of the growth mechanism show that this layered copper oxide phase is a kinetic product in contrast to the thermodynamic one typically produced in solid state reactions. We have exploited this kinetic growth mode to prepare Sr{sub 2-x}M{sub x}CuO{sub 3+{delta}} solids that have systematic variations in oxygen and cation stoichiometry. 26 refs., 2 figs.

Morales, A.M.; Yang, P.; Lieber, C.M. [Harvard Univ., Cambridge, MA (United States)

1994-09-07

346

Assessment of sacrificial anode impact by aluminum accumulation in mussel Mytilus edulis: a large-scale laboratory test.  

UK PubMed Central (United Kingdom)

Since the early 1960s, the application of aluminum alloy sacrificial anodes to mitigate marine corrosion has been well known. The aim of this work was to study aluminum bioconcentration in Mytilus edulis by an in vitro test performed in two tanks: the first containing non-contaminated water (NCW) and the second containing aluminum-contaminated water (CW) (530 ?g L(-1)) released by sacrificial anode. The mussels were collected and examined over a period of 8 weeks. A comparison between the aluminum concentrations in the digestive glands of mussels from the CW and NCW tanks shows that the highest value (1700 mg/kg d.w.) was found in the CW mussels collected after 13 days. In NCW, the mean aluminum concentration in digestive glands during the test was 281 mg/kg d.w. The rapid concentration decrease in digestive glands is probably due to the inhibition of filtering activity due to valve closure at the high concentration as well as the induction of the detoxification response.

Mao A; Mahaut ML; Pineau S; Barillier D; Caplat C

2011-12-01

347

Replication of optical MEMS structures in sol–gel materials  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A replication method of fabrication for micro electro mechanical systems (MEMS) structures is presented, for use as an alternative to silicon processing. UV-curable ORMOCER® sol–gel is used as base material. The basic fabrication process involves deposition and patterning of a sacrificial spacer lay...

Obi, S.; Gale, M. T.; Kuoni, A.; de Rooij, Nicolaas F.

348

Characterization of CuInSe{sub 2} material and devices: comparison of thermal and electrochemically prepared absorber layers  

Energy Technology Data Exchange (ETDEWEB)

CuInSe{sub 2}-based absorber layers for photovoltaic devices have been fabricated using two different scalable processes, electrodeposition and sputtering, both followed by thermal annealing. The structural properties of the absorber layers were studied by SEM, XRD and MiniSIMS. Sputtered absorber layers exhibit larger grain sizes than electrodeposited layers, but both types of film consist of randomly orientated crystallites. Electrodeposited layers appear to have a uniform composition with evidence of a MoSe{sub 2} layer at the back contact, whilst sputtered layers show no evidence for a MoSe{sub 2} layer. The external quantum efficiency spectrum of films and completed devices was measured, and the band gap and broadening parameters were obtained using electroreflectance spectroscopy. A device based on electrodeposited CuInSe{sub 2} achieved an AM 1.5 efficiency of 6.6%, whilst a device based on sputtered CuInSe{sub 2} had an efficiency of 8.3%. Impedance measurements were used to calculate doping densities of 2 x 10{sup 16} and 4 x 10{sup 15} cm{sup -3} for the electrodeposited and sputtered devices, respectively.

Dale, P J; Samantilleke, A P; Peter, L M [Department of Chemistry, University of Bath, BA2 7AY (United Kingdom); Zoppi, G; Forbes, I [Northumbria Photovoltaics Applications Centre, Northumbria University, NE1 8ST (United Kingdom)], E-mail: phillip.dale@uni.lu

2008-04-21

349

Characterization of CuInSe2 material and devices: comparison of thermal and electrochemically prepared absorber layers  

International Nuclear Information System (INIS)

CuInSe2-based absorber layers for photovoltaic devices have been fabricated using two different scalable processes, electrodeposition and sputtering, both followed by thermal annealing. The structural properties of the absorber layers were studied by SEM, XRD and MiniSIMS. Sputtered absorber layers exhibit larger grain sizes than electrodeposited layers, but both types of film consist of randomly orientated crystallites. Electrodeposited layers appear to have a uniform composition with evidence of a MoSe2 layer at the back contact, whilst sputtered layers show no evidence for a MoSe2 layer. The external quantum efficiency spectrum of films and completed devices was measured, and the band gap and broadening parameters were obtained using electroreflectance spectroscopy. A device based on electrodeposited CuInSe2 achieved an AM 1.5 efficiency of 6.6%, whilst a device based on sputtered CuInSe2 had an efficiency of 8.3%. Impedance measurements were used to calculate doping densities of 2 x 1016 and 4 x 1015 cm-3 for the electrodeposited and sputtered devices, respectively.

2008-04-21

350

Fast and robust infiltration of functional material inside titania nanotube layers: case study of a chalcogenide glass sensitizer.  

UK PubMed Central (United Kingdom)

Fast and robust infiltration of anodic TiO2 nanotube layers with a model chalcogenide As3S7 glass via spin-coating is reported for the first time. Effective sensitization leads to a significant visible light photocurrent response. This easy and cheap infiltration method can be extended for deposition of other absorbers into nanotubular layers.

Macak JM; Kohoutek T; Wang L; Beranek R

2013-09-01

351

Intercalation synthesis of functional hybrid materials based on layered simple hydroxide hosts and ionic liquid guests--a pathway towards multifunctional ionogels without a silica matrix?  

UK PubMed Central (United Kingdom)

Functional hybrid materials on the basis of inorganic hosts and ionic liquids (ILs) as guests hold promise for a virtually unlimited number of applications. In particular, the interaction and the combination of properties of a defined inorganic matrix and a specific IL could lead to synergistic effects in property selection and tuning. Such hybrid materials, generally termed ionogels, are thus an emerging topic in hybrid materials research. The current article addresses some of the recent developments and focuses on the question why silica is currently the dominating matrix used for (inorganic) ionogel fabrication. In comparison to silica, matrix materials such as layered simple hydroxides, layered double hydroxides, clay-type substances, magnetic or catalytically active solids, and many other compounds could be much more interesting because they themselves may carry useful functionalities, which could also be exploited for multifunctional hybrid materials synthesis. The current article combines experimental results with some arguments as to how new, advanced functional hybrid materials can be generated and which obstacles will need to be overcome to successfully achieve the synthesis of a desired target material.

Delahaye E; Xie Z; Schaefer A; Douce L; Rogez G; Rabu P; Günter C; Gutmann JS; Taubert A

2011-10-01

352

Intercalation synthesis of functional hybrid materials based on layered simple hydroxide hosts and ionic liquid guests--a pathway towards multifunctional ionogels without a silica matrix?  

Science.gov (United States)

Functional hybrid materials on the basis of inorganic hosts and ionic liquids (ILs) as guests hold promise for a virtually unlimited number of applications. In particular, the interaction and the combination of properties of a defined inorganic matrix and a specific IL could lead to synergistic effects in property selection and tuning. Such hybrid materials, generally termed ionogels, are thus an emerging topic in hybrid materials research. The current article addresses some of the recent developments and focuses on the question why silica is currently the dominating matrix used for (inorganic) ionogel fabrication. In comparison to silica, matrix materials such as layered simple hydroxides, layered double hydroxides, clay-type substances, magnetic or catalytically active solids, and many other compounds could be much more interesting because they themselves may carry useful functionalities, which could also be exploited for multifunctional hybrid materials synthesis. The current article combines experimental results with some arguments as to how new, advanced functional hybrid materials can be generated and which obstacles will need to be overcome to successfully achieve the synthesis of a desired target material. PMID:21881660

Delahaye, Emilie; Xie, Zailai; Schaefer, Andreas; Douce, Laurent; Rogez, Guillaume; Rabu, Pierre; Günter, Christina; Gutmann, Jochen S; Taubert, Andreas

2011-09-01

353

Development of symmetric composition-gradient materials including hard particles in its surface layer; Hyosobu ni koshitsu ryushi wo fukumu taishogata sosei keisha zairyo no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Development of new materials with both thermal resistance and thermal shock resistance was studied on the basis of symmetric ceramics/metal/ceramics gradient composition. Al2O3/TiC/Ni/TiC/Al2O3 was used as material model of basic composition, and the system was selected where WC-Co system alloy hard particles were dispersed into the Al2O3 ceramic surface layer. The layered material was sintered in N2 gas atmosphere by SHS/HIP method using exothermic caused by nitriding reaction. Since cracks were generated in some specimens of 5-layer structure, improved specimens of 7-layer structure were prepared. To examine the effect of a particle size on toughness, WC-Co system alloy specimens with different particle sizes were also prepared. As a result, no cracks were found, and residual stress and fracture toughness were affected by particle size. In addition, the following were studied: technique of mass production, observation of fine structures, analysis of thermal stress, thermal shock resistance, and friction and abrasion characteristics. 13 refs., 65 figs., 15 tabs.

NONE

1997-03-01

354

Correction of the spectral lines of a laser plasma for measurement of the depth profile of layered materials in an ablation crater  

International Nuclear Information System (INIS)

An algorithm for the correction of the atomic lines in the spectrum of a laser plasma was developed for determination of the depth profile of the elemental composition of layered materials in an ablation crater. The application of this algorithm made it possible to eliminate the profile smoothing effect as a consequence of a change in the line intensity as the crater becomes deeper. The correction of the profile is illustrated by an example of measurement of the thickness of a diffusion layer of zinc-plated sheet steel before and after its heating at 4520C. (interaction of laser radiation with matter. laser plasma)

1999-10-31

355

Fabrication of metallic nanomasks by transfer of self-organized nanodot patterns from semiconductor material into thin metallic layers  

Energy Technology Data Exchange (ETDEWEB)

The basic understanding of the formation of highly regular nanostructures during ion erosion of amorphous GaSb layers is revised. The essential physical parameters for the formation of the highly regular dot pattern are discussed. Numerical modelling based on the stabilized isotropic Kuramoto-Sivashinsky equation is presented and discussed. The experimental part of this contribution presents the successful pattern transfer into metallic buried thin layers as well as into Silicon underlayers. The critical conditions for this transfer technique are discussed. Application potential of using this self-organization scheme for the generation of highly regular patterns in ferromagnetic metal layers as well as in crystalline silicon is estimated.

Bobek, T. [Institute of Semiconductor Electronics, Aachen University, Sommerfeldstrasse 24, 52074 Aachen (Germany)]. E-mail: bobek@iht.rwth-aachen.de; Kurz, H. [Institute of Semiconductor Electronics, Aachen University, Sommerfeldstrasse 24, 52074 Aachen (Germany)

2007-04-15

356

Fabrication of metallic nanomasks by transfer of self-organized nanodot patterns from semiconductor material into thin metallic layers  

International Nuclear Information System (INIS)

The basic understanding of the formation of highly regular nanostructures during ion erosion of amorphous GaSb layers is revised. The essential physical parameters for the formation of the highly regular dot pattern are discussed. Numerical modelling based on the stabilized isotropic Kuramoto-Sivashinsky equation is presented and discussed. The experimental part of this contribution presents the successful pattern transfer into metallic buried thin layers as well as into Silicon underlayers. The critical conditions for this transfer technique are discussed. Application potential of using this self-organization scheme for the generation of highly regular patterns in ferromagnetic metal layers as well as in crystalline silicon is estimated.

2007-01-01

357

The Hardness of Boride Layer on the S45C Iron (A preliminary study on surface hardening of ferrous material)  

Directory of Open Access Journals (Sweden)

Full Text Available The property such as microhardness of boride layer formed on S45C iron was investigated. Boronizing was carried out in a solid medium consisting of nano size powders of 50% B4C as a donor, 45% SiC as a diluent, and 5% KBF4 as an activator treated at the temperature of 10000C for 8 hours. The phases that were formed on the substrate was found as Fe2B and FeB layer that had smooth and flate shape morphology. The hardness of boride layer on S45C was over 2000 HV, while the hardness of untreated S45C iron was about 196,39 HV. Depending on process time and temperature, the depth of boride layer ranges from 25 to 55 µm, leading to a diffusion controlled process

Sutrisno; Bambang Soegijono

2012-01-01

358

Electroreductive polymerization of dimethyldichlorosilane by polarity-alternated electrolysis in an undivided cell with sacrificial aluminum electrodes  

Energy Technology Data Exchange (ETDEWEB)

Poly (dimethylsilane) s were provided by electroreductive polymerization of dimethyldichlorosilane, and characterized by gel permiation chromatography and ultraviolet or infrared spectroscopy. Polarity-alternated electrolysis at intervals of 30 min was used for the undivided cell with an aluminum cathode and a sacrificial aluminum anode in dimethoxyethane containing tetrabutylammonium chloride supporting electrolyte. Removal of a diaphragm in the cell resulted in simple cell structure and considerable decrease in average cell voltage during electrolysis, and a high current efficiency and yield in electrolysis were also attained. The poly (dimethylsilane) s obtained could be converted into corresponding polycarbosilanes as preferable precursors for producing silicon carbide ceramics and fibers. On the other hand, the polymerization was unsuccessful in a divided cell with ion-exchange resin membranes as substitute for a glass frit diaphragm. 18 refs., 3 figs., 2 tabs.

Umezawa, M.; Ichikawa, H.; Ishikawa, T. (Nippon Carbon Co. Ltd., Yokohama (Japan)); Nonaka, T. (Tokyo Institute of Technology, Tokyo (Japan))

1991-05-05

359

Self-sacrificial templating synthesis of porous quaternary Cu–Fe–Sn–S semiconductor nanotubes via microwave irradiation  

International Nuclear Information System (INIS)

Uniform quaternary Cu2FeSnS4 (CITS) nanotubes of outer diameter 400–800 nm and thickness 100–200 nm have been synthesized for the first time by a simple, rapid and easily scaled-up microwave nonaqueous route using benzyl alcohol as the microwave absorbing solvent. An interesting in situ generated one-dimensional Cu(Tu)Cl nanorod acting as a self-sacrificial template was crucial for the formation of the well-defined CITS nanotubes. Based on the designed time-dependent experiments, a formation mechanism for the CITS nanotubes was also proposed. The resulting CITS nanotubes had a strong absorption in the visible region with a bandgap of 1.71 eV that was optimal for photovoltaic applications. Our study provided a microwave nonaqueous route generally applicable for the synthesis of quaternary chalcogenide semiconductor nanotubes. (paper)

2012-12-14

360

Effect of zinc sacrificial anode degradation on the defence system of the Pacific oyster, Crassostrea gigas: chronic and acute exposures.  

UK PubMed Central (United Kingdom)

Two types of exposures were performed to assess the effects of zinc released from sacrificial anode degradation: a chronic exposure, in which oysters were exposed to 0.53±0.04 mg Zn L(-1) for 10 weeks, and an acute exposure, where oysters were exposed to 10.2±1.2 mg Zn L(-1) for 1 week. At the end of the acute exposure experiment, 81.8% mortality was recorded. In contrast, no mortality was detected after 10 weeks exposure. Moreover, all of the immune system biomarkers studied, except the number of circulating haemocytes, were stimulated by a moderate level of zinc and inhibited by a high level. Our exposure conditions did not induce SOD or MXR mRNA expression in gills and digestive gland. However, an increase of MT mRNA is observed in these tissues. The results indicate that oysters are sensitive to acute zinc toxicity but are only moderately affected by a mild zinc concentration.

Mottin E; Caplat C; Latire T; Mottier A; Mahaut ML; Costil K; Barillier D; Lebel JM; Serpentini A

2012-09-01

 
 
 
 
361

Flaw detection in multi-layer, multi-material composites by resonance imaging: Utilizing Air-coupled Ultrasonics and Finite Element Modeling  

Science.gov (United States)

Ceramic tiles are the main ingredient of a multi-material, multi-layered composite being considered for the modernization of tank armors. The high stiffness, low attenuation, and precise dimensions of these uniform tiles make them remarkable resonators when driven to vibrate. Defects in the tile, during manufacture or after usage, are expected to change the resonance frequencies and resonance images of the tile. The comparison of the resonance frequencies and resonance images of a pristine tile/lay-up to a defective tile/lay-up will thus be a quantitative damage metric. By examining the vibrational behavior of these tiles and the composite lay-up with Finite Element Modeling and analytical plate vibration equations, the development of a new Nondestructive Evaluation technique is possible. This study examines the development of the Air-Coupled Ultrasonic Resonance Imaging technique as applied to a hexagonal ceramic tile and a multi-material, multi-layered composite.

Livings, Richard Andrew

362

Study on metal microparticle content of the material transferred with Absorbing Film Assisted Laser Induced Forward Transfer when using silver absorbing layer  

International Nuclear Information System (INIS)

Absorbing Film Assisted Laser Induced Forward Transfer (AFA-LIFT) is a modified LIFT method where a high absorption coefficient thin film coating of a transparent substrate is used to transform the laser energy into kinetic in order to transfer the 'target' material spread on it. This method can be used for the transfer of biomaterials and living cells, which could be damaged by direct irradiation of the laser beam. In previous experiments, ?50-100 nm thick metal films have been used as absorbing layer. The transferred material can also contain metal microparticles originating from the absorbing thin film and acting as non-desired impurities in some cases. The aim of our work was to study how the properties (number, size and covered area) of metal particles transferred during the AFA-LIFT process depend on film thickness and the applied fluence. Silver thin films with different thickness (50-400 nm) were used as absorbing layers and real experimental conditions were modeled by a 100 ?m thick water layer. The particles transferred without the use of water layer were also studied. The threshold laser fluence for the complete removal of the absorber from the irradiated area was found to strongly increase with increasing film thickness. The deposited micrometer and submicrometer particles were observed with optical microscope and atomic force microscope. Their size ranged from 100 nm to 20 ?m and depended on the laser fluence. The increase in fluence resulted in an increasing number of particles of smaller average size.

2006-04-30

363

Catalyst-free direct growth of a single to a few layers of graphene on a germanium nanowire for the anode material of a lithium battery.  

UK PubMed Central (United Kingdom)

Direct growth of a single to a few layers of graphene on a germanium nanowire (Gr/Ge NW; see picture) was achieved by a metal-catalyst-free chemical vapor deposition (CVD) process. The Gr/Ge NW was used as anode in a lithium ion battery. This material has a specific capacity of 1059 mA h g(-1) at 4.0 C, a long cycle life over 200 cycles, and a high capacity retention of 90%.

Kim H; Son Y; Park C; Cho J; Choi HC

2013-06-01

364

Catalyst-free direct growth of a single to a few layers of graphene on a germanium nanowire for the anode material of a lithium battery.  

Science.gov (United States)

Direct growth of a single to a few layers of graphene on a germanium nanowire (Gr/Ge NW; see picture) was achieved by a metal-catalyst-free chemical vapor deposition (CVD) process. The Gr/Ge NW was used as anode in a lithium ion battery. This material has a specific capacity of 1059 mA h g(-1) at 4.0 C, a long cycle life over 200 cycles, and a high capacity retention of 90%. PMID:23616396

Kim, Hyungki; Son, Yoonkook; Park, Chibeom; Cho, Jaephil; Choi, Hee Cheul

2013-04-24

365

Thin layer activation technique for the determination of surface wear in zircaloy material used in primary coolant channel in nuclear reactors  

International Nuclear Information System (INIS)

Thin layer activation (TLA) technique is a very sensitive and accurate nuclear technique for the determination of surface wear in micron order in the engineering components. TLA technique has been developed and standardised using 40 Mev ?-particles from Variable Energy Cyclotron (VEC) machine at Calcutta. It has been first applied successfully in Fe and Ni based alloy materials. The application of TLA technique with methodology in zircaloy material to determine the surface wear is presented here in brief and the sensitivity of the wear measurement is found to be 0.2 ?m. (author)

1998-01-01

366

Layered Li-Mn-oxide with the O2 structure: A cathode material for Li-ion cells which does not convert to spinel  

International Nuclear Information System (INIS)

Layered sodium manganese bronzes having the P2 structure (Na2/3[Li5/6]O2), were used to prepare layered lithium manganese oxides by ion exchange of Na by Li using LiBr in hexanol. X-ray diffraction and chemical analysis show that layered Li2/3[Li1/6Mn5/6]O2 has an O2 type structure. The arrangement of manganese and oxygen atoms in this phase differs fundamentally from that found in layered LiMnO2(O3 structure), in orthorhombic LiMnO2, and in spinel Li2Mn2O4 so that conversion to spinel during electrochemical cycling is not expected. Li2/3[Li1/6Mn5/6]O2 as well as the related Li2/3[Li1/18Mn17/18]O2 and Li2/3[Mn0.85Co0.15]O2 have a reversible charge capacity of about 150 mAh/g. During cycling the new cathode materials do not convert to spinel, in contrast to the behavior of layered and orthorhombic LiMnO2

1999-01-01

367

Layered Li-Mn-oxide with the O2 structure: A cathode material for Li-ion cells which does not convert to spinel  

Energy Technology Data Exchange (ETDEWEB)

Layered sodium manganese bronzes having the P2 structure (Na{sub 2/3}[Li{sub 5/6}]O{sub 2}), were used to prepare layered lithium manganese oxides by ion exchange of Na by Li using LiBr in hexanol. X-ray diffraction and chemical analysis show that layered Li{sub 2/3}[Li{sub 1/6}Mn{sub 5/6}]O{sub 2} has an O2 type structure. The arrangement of manganese and oxygen atoms in this phase differs fundamentally from that found in layered LiMnO{sub 2}(O3 structure), in orthorhombic LiMnO{sub 2}, and in spinel Li{sub 2}Mn{sub 2}O{sub 4} so that conversion to spinel during electrochemical cycling is not expected. Li{sub 2/3}[Li{sub 1/6}Mn{sub 5/6}]O{sub 2} as well as the related Li{sub 2/3}[Li{sub 1/18}Mn{sub 17/18}]O{sub 2} and Li{sub 2/3}[Mn{sub 0.85}Co{sub 0.15}]O{sub 2} have a reversible charge capacity of about 150 mAh/g. During cycling the new cathode materials do not convert to spinel, in contrast to the behavior of layered and orthorhombic LiMnO{sub 2}.

Paulsen, J.M.; Thomas, C.L.; Dahn, J.R.

1999-10-01

368

Analysis of the characteristics of a white organic LED using the newly synthesized blue material methyl-DPVT by varying the thickness of the DPVBi layer  

International Nuclear Information System (INIS)

A two-wavelength type of white organic light-emitting diode (OLED) having a blue/orange emitting layer was fabricated by synthesizing Methyl-DPVT, a new derivative of the blue-emitting material DPVBi on the market. The white-emission of the two-wavelength type was successfully obtained by representing not only blue emission by using DPVBi but also orange emission by using methyl-DPVT as a host material and Rubrene as a guest material. The basic structure of the fabricated white OLED is glass/ITO/NPB(150 A)/DPVBi/methyl-DPVT :Rubrene [2.0 wt%](100 A)/BCP(70 A)/Alq3(150 A)/Al(600 A). To evaluate the characteristics of the devices, we varied the thickness of the DPVBi layer from 100 A to 80 A to 60 A. A nearly pure white-emission was obtained in CIE coordinates of (0.3327, 0.3397) when the DPVBi layer was 60-A thick at an applied voltage of 11 V. The device started to operate at 1 V and to emit light at 2.5 V. The external quantum efficiency was above 0.5 % both when almost all of the current was injected and the applied voltage was over 10 V. A superior maximum quantum effciency of 0.746 % was obtained at an applied voltage of 18.5 V.

2004-01-01

369

Analysis of the characteristics of a white organic LED using the newly synthesized blue material methyl-DPVT by varying the thickness of the DPVBi layer  

Energy Technology Data Exchange (ETDEWEB)

A two-wavelength type of white organic light-emitting diode (OLED) having a blue/orange emitting layer was fabricated by synthesizing Methyl-DPVT, a new derivative of the blue-emitting material DPVBi on the market. The white-emission of the two-wavelength type was successfully obtained by representing not only blue emission by using DPVBi but also orange emission by using methyl-DPVT as a host material and Rubrene as a guest material. The basic structure of the fabricated white OLED is glass/ITO/NPB(150 A)/DPVBi/methyl-DPVT :Rubrene [2.0 wt%](100 A)/BCP(70 A)/Alq{sub 3}(150 A)/Al(600 A). To evaluate the characteristics of the devices, we varied the thickness of the DPVBi layer from 100 A to 80 A to 60 A. A nearly pure white-emission was obtained in CIE coordinates of (0.3327, 0.3397) when the DPVBi layer was 60-A thick at an applied voltage of 11 V. The device started to operate at 1 V and to emit light at 2.5 V. The external quantum efficiency was above 0.5 % both when almost all of the current was injected and the applied voltage was over 10 V. A superior maximum quantum effciency of 0.746 % was obtained at an applied voltage of 18.5 V.

Oh, Hwan-Sool; Cho, Jae-Young [Konkuk University, Seoul (Korea, Republic of); Yoon, Seok-Beom [Kongju National University, Kongju (Korea, Republic of)

2004-08-15

370

Design, materials and R ampersand R issues of innovative thermal contact joints for high heat flux applications  

International Nuclear Information System (INIS)

Plasma facing components in fusion machines are generally designed with a layer of low-Z material facing the plasma, and some other material in contact with the coolant. One of the most critical issues associated with making the proposed design concept work, from a power handling point of view, is achieving the necessary contact conductance between the armor and the heat sink. Bonded attachments (i.e., brazed joints) have been favored in the past because of their superior thermal conductance with respect to mechanical attachment schemes based, for example, on the use of solid compliant layers. As a matter of fact, providing the high contact pressure required to ensure a high level of thermal conductance across the interface, over most of the area, will be a challenge even on initial installation. Maintaining that high level over the life of the component, given the dimension and stress effects resulting from irradiation, will be very difficult. However, for brazed joints, most of the database available today is still inconclusive in terms of the integrity and the expected lifetime of the interface in such designs for typical reactor conditions. This paper describes new design/materials ideas which could represent promising alternatives to some of the existing concepts. The underlying design approach is to combine a sacrificial armor to an actively cooled permanent part via a compliant layer of a conventional solder alloy in the rheocast condition.

1994-07-01

371

Design, materials and R&R issues of innovative thermal contact joints for high heat flux applications  

Energy Technology Data Exchange (ETDEWEB)

Plasma facing components in fusion machines are generally designed with a layer of low-Z material facing the plasma, and some other material in contact with the coolant. One of the most critical issues associated with making the proposed design concept work, from a power handling point of view, is achieving the necessary contact conductance between the armor and the heat sink. Bonded attachments (i.e., brazed joints) have been favored in the past because of their superior thermal conductance with respect to mechanical attachment schemes based, for example, on the use of solid compliant layers. As a matter of fact, providing the high contact pressure required to ensure a high level of thermal conductance across the interface, over most of the area, will be a challenge even on initial installation. Maintaining that high level over the life of the component, given the dimension and stress effects resulting from irradiation, will be very difficult. However, for brazed joints, most of the database available today is still inconclusive in terms of the integrity and the expected lifetime of the interface in such designs for typical reactor conditions. This paper describes new design/materials ideas which could represent promising alternatives to some of the existing concepts. The underlying design approach is to combine a sacrificial armor to an actively cooled permanent part via a compliant layer of a conventional solder alloy in the rheocast condition.

Federici, G.; Matera, R.; Chiocchio, S. [Max-Planch-Institut fuer Plasmaphysik, Garching Muenchen (Germany)] [and others

1994-12-31

372

Synthesis and Characterization of a Layered Manganese Oxide: Materials Chemistry for the Inorganic or Instrumental Methods Lab  

Science.gov (United States)

A three-week laboratory project involving synthesis and characterization of a layered manganese oxide provides an excellent vehicle for teaching important concepts of inorganic chemistry and instrumental methods related to non-molecular systems. Na-birnessite is an easily prepared manganese oxide with a 7 A interlayer spacing and Na[superscript +]…

Ching, Stanton; Neupane, Ram P.; Gray, Timothy P.

2006-01-01

373

Multi-layered transducer array and method having identical layers  

UK PubMed Central (United Kingdom)

Multiple layer elements for a transducer array are provided. Each element comprises two or more layers of transducer material. Various of the elements include one or more of: (1) multiple-layer, multiple-dimensional arrays where the layers are polymericly bonded and electrically connected through asperity contact, (2) multiple layer array of elements where air or gas separates at least two elements, (3) an even number of layers where each layer is electrically connected through asperity contact, (4) multiple-layers where each layer comprises transducer material and electrodes in a substantially same configuration, and (5) electrically isolating electrodes on layers by kerfing or cutting after bonding the layers together.

MOHR III JOHN P; WALTERS WORTH B; AYTER SEVIG

374

High-energy 'composite' layered manganese-rich cathode materials via controlling Li2MnO3 phase activation for lithium-ion batteries.  

UK PubMed Central (United Kingdom)

The 'composite' layered materials for lithium-ion batteries have recently attracted great attention owing to their large discharge capacities. Here, the 0.5Li(2)MnO(3)·0.5LiMn(0.42)Ni(0.42)Co(0.16)O(2)'composite' layered manganese-rich material is prepared and characterized by the synchrotron X-ray powder diffraction (SXPD). The relationship between its electrochemical performance and its 'composite' components, the Li(2)MnO(3) phase activation process during cycling and the cycle stability of this material at room temperature are elucidated based on its kinetic controlled electrochemical properties, dQ/dV curves and Raman scattering spectroscopies associated with different initial charge-discharge current densities (5 mA g(-1), 20 mA g(-1) and 50 mA g(-1)), cut-off voltages (4.6 V and 4.8 V) and cycle numbers (50 cycles and 150 cycles). Furthermore, its reaction pathways are tracked via a firstly introduced integrated compositional phase diagram of four components, Li(2)MnO(3), LiMn(0.42)Ni(0.42)Co(0.16)O(2), MO(2) (M = Mn(1-?-?)Ni(?)Co(?); 0 ??? 5/12, 0 ??? 1/6) and LiMnO(2), which turns out to be a very important guiding tool for understanding and utilizing this 'composite' material.

Yu H; Kim H; Wang Y; He P; Asakura D; Nakamura Y; Zhou H

2012-05-01

375

High-energy 'composite' layered manganese-rich cathode materials via controlling Li2MnO3 phase activation for lithium-ion batteries.  

Science.gov (United States)

The 'composite' layered materials for lithium-ion batteries have recently attracted great attention owing to their large discharge capacities. Here, the 0.5Li(2)MnO(3)·0.5LiMn(0.42)Ni(0.42)Co(0.16)O(2)'composite' layered manganese-rich material is prepared and characterized by the synchrotron X-ray powder diffraction (SXPD). The relationship between its electrochemical performance and its 'composite' components, the Li(2)MnO(3) phase activation process during cycling and the cycle stability of this material at room temperature are elucidated based on its kinetic controlled electrochemical properties, dQ/dV curves and Raman scattering spectroscopies associated with different initial charge-discharge current densities (5 mA g(-1), 20 mA g(-1) and 50 mA g(-1)), cut-off voltages (4.6 V and 4.8 V) and cycle numbers (50 cycles and 150 cycles). Furthermore, its reaction pathways are tracked via a firstly introduced integrated compositional phase diagram of four components, Li(2)MnO(3), LiMn(0.42)Ni(0.42)Co(0.16)O(2), MO(2) (M = Mn(1-?-?)Ni(?)Co(?); 0 ??? 5/12, 0 ??? 1/6) and LiMnO(2), which turns out to be a very important guiding tool for understanding and utilizing this 'composite' material. PMID:22456724

Yu, Haijun; Kim, Hyunjeong; Wang, Yarong; He, Ping; Asakura, Daisuke; Nakamura, Yumiko; Zhou, Haoshen

2012-03-28

376

Phase separated thermotropic layers based on UV cured acrylate resins. Effect of material formulation on overheating protection properties and application in a solar collector  

Energy Technology Data Exchange (ETDEWEB)

This paper focuses on the effect of material composition on the overheating protection properties of thermotropic systems with fixed domains for solar thermal collectors. Numerous functional layers were prepared by a variation of base resin (polyester-, epoxy- or urethane-acrylate) and of thermotropic additives (non-polar and polar waxes) as well as by additive concentration (5 and 7 wt%). A detailed investigation of optical properties, switching temperature and switching process was performed applying UV/Vis/NIR spectroscopy. Thermal transitions of both the thermotropic layers and the additives used were determined by Differential Scanning Calorimetry (DSC). The capability of the produced thermotropic layers to reduce stagnation temperatures in an all-polymeric flat plate collector was evaluated by theoretical modeling. The thermotropic layers showed a hemispheric solar transmittance between 76% and 87% in clear state. Above the switching threshold this transmittance changed by 1-16% to values between 62% and 85%. The layers exhibited switching temperatures between 33 and 80 C. The transition is fully completed within a temperature frame of 10-25 C. Resin types with higher glass transition temperatures were detected to benefit the reduction of the hemispheric solar transmittance above the switching threshold. This reduction was also found to increase with increasing molecular weight of the non-polar additive types. The comparison of the switching performance with the thermal transitions of the additives revealed a good correlation. Theoretical modeling showed that by the use of selected thermotropic layers in the glazing the maximum absorber temperatures can be limited to temperatures below 130 C. (author)

Resch, Katharina [Polymer Competence Center Leoben GmbH, Roseggerstrasse 12, 8700 Leoben (Austria); Wallner, Gernot M. [Institute of Materials Science and Testing of Plastics, University of Leoben, Franz-Josef Strasse 18, 8700 Leoben (Austria); Hausner, Robert [AEE - Institut fuer Nachhaltige Technologien (AEE-INTEC), Feldgasse 19, 8200 Gleisdorf (Austria)

2009-09-15

377

Thermal stress in a bi-material assembly with a 'piecewise-continuous' bonding layer: theorem of three axial forces  

Energy Technology Data Exchange (ETDEWEB)

We consider a bi-material assembly with a 'piecewise-continuous' bonding layer. The layer is characterized by different elastic constants of its 'pieces' (segments) and is assumed to be thin. Young's moduli of all the 'pieces' of the bonding layer are significantly lower than the moduli of the adherend materials. In such a situation the coefficient of thermal expansion (CTE) of the bonding material need not be accounted for. Only the interfacial compliance of the bonding layer is important. This is indeed the case for the majority of electronic, opto-electronic or photonic assemblies. We consider the situation when the assembly is manufactured at an elevated temperature and is subsequently cooled down to a low (say, room) temperature. The objective of the analysis is to develop a simple, easy-to-use and physically meaningful analytical ('mathematical') predictive model for the evaluation of the interfacial shearing stresses that arise at the boundaries of the 'pieces' (segments) of the bonding layer and at the assembly edge. The basic equation is obtained for the thermally induced forces acting in the adherends' cross-sections that correspond to the boundaries between the dissimilar portions of the bonding layer. This equation has the form of the theorem of three (bending) moments in the theory of multi-span beams lying on separate simple supports and could therefore be called the 'theorem of three axial forces'. We show, as an illustration, how this equation could be employed to design a bi-material assembly with an inhomogeneous bonding layer and with low interfacial shearing stresses. Low shearing stresses will certainly result in lower peeling stresses as well. The numerical example is carried out for an assembly with a relatively high-modulus bonding material in its mid-portion (aimed primarily at providing good adhesion and, if necessary, good heat transfer as well) and a low-modulus material in its peripheral portions (aimed primarily at bringing down the interfacial stresses). The maximum interfacial shearing stress in the assembly with the inhomogeneous bonding layer turned out to be only about 30% of the maximum shearing stress in an assembly with a homogeneous bonding layer having throughout its length the same modulus as the bonding material in the mid-portion of an assembly with an inhomogeneous bond. We would like to emphasize that the inhomogeneous bonding material addressed in this analysis does not necessarily have to be an epoxy one. Many other bonding materials with different moduli in the mid-portion and at the peripheral portions of the assembly could be considered for various practical applications. For instance, a high-modulus solder material such as, say, a tin-silver-copper (SAC) solder can be employed in the mid-portion of an assembly and a low-modulus solder (e.g. an indium-based alloy) at its peripheral portions. In other applications a high-modulus solder material could be considered for the mid-portion of the assembly and a low-modulus epoxy adhesive at its peripheral portions. We would also like to point out that the developed concept can be easily generalized for the situations when the bonding material is not a continuous one, but is of the ball-grid-array (BGA) or a pad-grid-array (PGA) type. Our concept could also be easily generalized for a two-dimensional case, for the situation when bending deformations should be accounted for, for non-uniform distribution of temperature (i.e. for assemblies with temperature gradients in the through-thickness and/or in the longitudinal direction), for situations when time-dependent effects (visco-elasticity, creep, stress relaxation) in the bonding material are important and for numerous other more complicated and practically important situations that might be encountered in engineering practice.

Suhir, E, E-mail: suhire@aol.co [Department of Electrical Engineering, University of California, Santa Cruz, CA (United States); Department of Mechanical Engineering, University of Maryland, College Park, MD (United States); ERS Company LLC, 727 Alvina Ct., Los Altos, CA 94024 (United States)

2009-02-21

378

Structural analysis and characterization of layer perovskite oxynitrides made from Dion-Jacobson oxide precursors  

International Nuclear Information System (INIS)

A three-layer oxynitride Ruddlesden-Popper phase Rb1+xCa2Nb3O10-xNx.yH2O (x=0.7-0.8, y=0.4-0.6) was synthesized by ammonialysis at 800oC from the Dion-Jacobson phase RbCa2Nb3O10 in the presence of Rb2CO3. Incorporation of nitrogen into the layer perovskite structure was confirmed by XPS, combustion analysis, and MAS NMR. The water content was determined by thermal gravimetric analysis and the rubidium content by ICP-MS. A similar layered perovskite interconversion occurred in the two-layer Dion-Jacobson oxide RbLaNb2O7 to yield Rb1+xLaNb2O7-xNx.yH2O (x=0.7-0.8, y=0.5-1.0). Both compounds were air- and moisture-sensitive, with rapid loss of nitrogen by oxidation and hydrolysis reactions. The structure of the three-layer oxynitride Rb1.7Ca2Nb3O9.3N0.7.0.5H2O was solved in space group P4/mmm with a=3.887(3) and c=18.65(1)A, by Rietveld refinement of X-ray powder diffraction data. The two-layer oxynitride structure Rb1.8LaNb2O6.3N0.7.1.0H2O was also determined in space group P4/mmm with a=3.934(2) and c=14.697(2)A. GSAS refinement of synchrotron X-ray powder diffraction data showed that the water molecules were intercalated between a double layer of Rb+ ions in both the two- and three-layer Ruddlesden-Popper structures. Optical band gaps were measured by diffuse reflectance UV-vis for both materials. An indirect band gap of 2.51eV and a direct band gap of 2.99eV were found for the three-layer compound, while an indirect band gap of 2.29eV and a direct band gap of 2.84eV were measured for the two-layer compound. Photocatalytic activity tests of the three-layer compound under 380nm pass filtered light with AgNO3 as a sacrificial electron acceptor gave a quantum yield of 0.025% for oxygen evolution.

2005-01-01

379

Tuning the stability of graphene layers by phthalocyanine-based oPPV oligomers towards photo- and redoxactive materials.  

UK PubMed Central (United Kingdom)

In contrast to pristine zinc phthalocyanine (1), zinc phthalocyanine based oPPV-oligomers (2-4) of different chain lengths interact tightly and reversibly with graphite, affording stable and finely dispersed suspensions of mono- to few-layer graphene-nanographene (NG)-that are photoactive. The p-type character of the oPPV backbones and the increasing length of the oPPV backbones facilitate the overall ?-? interactions with the graphene layers. In NG/2, NG/3, and NG/4 hybrids, strong electronic coupling between the individual components gives rise to charge transfer from the photoexcited zinc phthalocyanines to NG to form hundreds of picoseconds lived charge transfer states. The resulting features, namely photo- and redoxactivity, serve as incentives to construct and to test novel solar cells. Solar cells made out of NG/4 feature stable and repeatable photocurrent generation during several 'on-off' cycles of illumination with monochromatic IPCE values of around 1%.

Brinkhaus L; Katsukis G; Malig J; Costa RD; Garcia-Iglesias M; Vázquez P; Torres T; Guldi DM

2013-07-01

380

New Layered Structures of Cuprous Chalcogenides as Thin Film Solar Cell Materials: Cu2Te and Cu2Se  

Science.gov (United States)

The stable crystal structures of two cuprous chalcogenides of Cu2X (X=Te or Se) are predicted using an adaptive genetic algorithm in combination with first-principles density functional theory calculations. Both systems are found to prefer a unique and previously unrecognized layered structure, with the total energies much lower than all structures proposed in the literature so far. The newly discovered structures are further shown to be dynamically and mechanically stable, and possess electronic properties consistent with existing experimental observations. In particular, their layered nature is expected to prevail over other structural forms at the interfaces of thin-film solar cells, and knowledge about the precise atomic structures of the interfaces is a prerequisite for achieving long-term stability and high efficiency of CdTe and Cu(In,Ga)Se2 solar cells.

Nguyen, Manh Cuong; Choi, Jin-Ho; Zhao, Xin; Wang, Cai-Zhuang; Zhang, Zhenyu; Ho, Kai-Ming

2013-10-01

 
 
 
 
381

An approach to achieve layered spintronics material using brownmillerite compound Ca2.5Sr0.5GaMn2O8  

Science.gov (United States)

Magnetic and magnetotransport properties of the naturally occurring layered compounds Ca2.5- x La x Sr0.5GaMn2O8 ( x = 0, 0.05, 0.075, and 0.1) have been reported. We have succeeded to introduce ferromagnetic ordering in the pure antiferromagnetic system Ca2.5Sr0.5GaMn2O8 by varying the ratio between Mn3+ and Mn4+ ions. The experimental results of magnetization, magnetoresistance, and neutron diffraction were interpreted on the basis of an electronic phase separation model, where a formation of ferromagnetic clusters (due to DE interactions) inside the layered antiferromagnetic matrix (due to superexchange interactions) in the La-substituted compounds is proposed. Significantly, the present study shows that the magnetic and electronic properties of the layered system Ca2.5Sr0.5GaMn2O8 can be tuned/optimized by appropriate chemical substitution to achieve a new spintronic material based on naturally occurring layered system for practical applications.

Yusuf, S. M.; Bera, A. K.

2013-05-01

382

Unusual Application Of Ion Beam Analysis For The Study Of Surface Layers On Materials Relevant To Cultural Heritage  

International Nuclear Information System (INIS)

Recently a new thematic of research -- intentional patinas on antic copper-base objects -- lead the AGLAE (Accelerateur Grand Louvre pour l'Analyse Elementaire) team of the C2RMF (Centre de Recherche et de Restauration des Musees de France) to improve its methods of analyzing thin surface layers both in their elemental composition and in-depth elemental distribution. A new beam extraction set-up containing a particle detector has been developed in order to use a 6 MeV alpha beam both in PIXE and RBS mode and to monitor precisely the ion dose received by the sample. Both RBS and ionization cross sections were assessed in order to make sure that the analysis can be quantitative. This set up allows great progresses in the understanding of both nature and structure of this very particular oxide layer obtained in the antiquity by chemical treatment on copper alloys, containing gold and/or silver and presenting very interesting properties of color and stability.Besides the non destructive properties of the IBA in external beam mode, this method of analyzing allows the study of samples in interaction with its environment. This was used to study the high temperature oxidation of Cu-Sn alloys using a furnace developed in order to heat a sample and analyze it in RBS mode at the same time. This new way of studying the growth of oxide layers permits to understand the oxidation mechanism of this system and to propose an experimental model for the identification of oxide layers due to an exposition to a high temperature, model needed for a long time by curators in charge of the study and the conservation of archaeological bronzes.

2006-12-01

383

Effect of new materials as under and cap layers on thermal stability of synthetic bottom spin valves  

International Nuclear Information System (INIS)

We investigated the thermal stability of the Ta-, ZrAl- and TiAl-based synthetic bottom spin valves. In the as-deposited state, the MR ratios of ZrAl- and TiAl-based synthetic SVs (SSV) are similar to that of the Ta-based SV. However, after annealed at 400 deg. C for 10 min, the MR ratio of Ta-based SV decreased by 42.5% (from 7.43% to 4.27%). On the other hand, the MR ratio of ZrAl- and TiAl-based SSVs increased 0.3% (from 7.37% to 7.39%) and 13.3% (from 7.47% to 8.46%), respectively. Auger depth profile clearly showed that ZrAl- and TiAl-based SSVs have higher interdiffusion resistance than Ta-based SV. Especially, diffusion of Mn from antiferromagnet layer to pinned layer was suppressed in TiAl-based SVs. The root-mean-square (RMS) roughness of the TiAl layer (0.11 nm) was much smaller than those of the ZrAl (0.16 nm) and Ta layer (0.43 nm). Due to high affinity of Ti or Al with oxygen, very stable and dense TiAl-oxides were formed at the surface during annealing. Thermal stability of TiAl- and ZrAl-based SSVs was enhanced due to surface uniformity and high passivity of TiAl- and ZrAl-oxides.

2007-01-01

384

Properties of SiC and problems of the material for use as the coating layer of fuel particles  

International Nuclear Information System (INIS)

The properties of silicon carbide (SiC) reported in the literatures and obtained in the authors' experiments, are reviewed with a view to improving the SiC coating layer of fuel particles for HTGR. Described are the deposition, physical and chemical properties, mechanical strength, diffusion and irradiation behaviors. The experimental results obtained in the authors' laboratory in in-pile irradiation and out-of-pile annealing of the SiC-coated particles are also presented. (auth.)

1975-01-01

385

Effect of new materials as under and cap layers on thermal stability of synthetic bottom spin valves  

Energy Technology Data Exchange (ETDEWEB)

We investigated the thermal stability of the Ta-, ZrAl- and TiAl-based synthetic bottom spin valves. In the as-deposited state, the MR ratios of ZrAl- and TiAl-based synthetic SVs (SSV) are similar to that of the Ta-based SV. However, after annealed at 400 deg. C for 10 min, the MR ratio of Ta-based SV decreased by 42.5% (from 7.43% to 4.27%). On the other hand, the MR ratio of ZrAl- and TiAl-based SSVs increased 0.3% (from 7.37% to 7.39%) and 13.3% (from 7.47% to 8.46%), respectively. Auger depth profile clearly showed that ZrAl- and TiAl-based SSVs have higher interdiffusion resistance than Ta-based SV. Especially, diffusion of Mn from antiferromagnet layer to pinned layer was suppressed in TiAl-based SVs. The root-mean-square (RMS) roughness of the TiAl layer (0.11 nm) was much smaller than those of the ZrAl (0.16 nm) and Ta layer (0.43 nm). Due to high affinity of Ti or Al with oxygen, very stable and dense TiAl-oxides were formed at the surface during annealing. Thermal stability of TiAl- and ZrAl-based SSVs was enhanced due to surface uniformity and high passivity of TiAl- and ZrAl-oxides.

Hyun, Eun-Kyung [Division of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Lee, Seong-Rae [Division of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of)]. E-mail: kumetsrl@korea.ac.kr

2007-03-15

386

On the possibility of experimental studies of dynamic material strength according to perturbation growth in magnetically driven layered liner systems  

International Nuclear Information System (INIS)

Explosive magnetic experiments confirmed the designed characteristics of three-layered liner systems (Al-H2O-Cu) and practicability of using water as a medium weakly inhibiting perturbation growth of the liners as opposed to polyethylene that showed a high yield strength, ?10-20 times higher than the quasi-static one. The paper presents calculations of liners used in these systems and their comparison with experimental data

2005-01-01

387

Effect of {gamma}-irradiation on commercial polypropylene based mono and multi-layered retortable food packaging materials  

Energy Technology Data Exchange (ETDEWEB)

Irradiation processing of food in the prepackaged form may affect chemical and physical properties of the plastic packaging materials. The effect of {gamma}-irradiation doses (2.5-10.0 kGy) on polypropylene (PP)-based retortable food packaging materials, were investigated using Fourier transform infrared (FTIR) spectroscopic analysis, which revealed the changes happening to these materials after irradiation. The mechanical properties decreased with irradiation while oxygen transmission rate (OTR) was not affected significantly. Colour measurement indicated that Nylon 6 containing multilayer films became yellowish after irradiation. Thermal characterization revealed the changes in percentage crystallinity.

George, Johnsy [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India)]. E-mail: g.johnsy@gmail.com; Kumar, R. [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India); Sajeevkumar, V.A. [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India); Sabapathy, S.N. [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India); Vaijapurkar, S.G. [Defence Laboratory, Ratanada Palace, Jodhpur, Rajastan 342011 (India); Kumar, D. [Defence Laboratory, Ratanada Palace, Jodhpur, Rajastan 342011 (India); Kchawahha, A. [Defence Laboratory, Ratanada Palace, Jodhpur, Rajastan 342011 (India); Bawa, A.S. [Defence Food Research Laboratory, Siddarthanagar, Mysore, Karnataka 570011 (India)

2007-07-15

388

A new, high current output, galvanic (sacrificial) anode, electrochemical rehabilitation system for reinforced and prestressed concrete structures  

Energy Technology Data Exchange (ETDEWEB)

This paper summarizes 1995 through 1998 laboratory, outdoor exposure facility, and field data on the subject concrete rehab system. The system shows promise as a means of providing cathodic protection to the reinforcing, as a chloride removal process, as a re-alkalization process, and/or as a lithium injection procedure to minimize alkali-aggregate reactions in the concrete. Unique characteristics of the system include: (1) Surrounding each galvanic anode with a highly corrosive liquid which maintains it (the anode) at peak output voltage throughout its life; and (2) Placing an ionic transfer layer between the anode and the concrete surface that is high volume, low resistivity and deliquescent (i.e. pulls water vapor out of the air at relative humidities of 35% or higher). The ionic transfer layer typically consists of sponge, felt or sand loaded with calcium chloride (and/or other chemicals such as sodium hydroxide, potassium acetate, and lithium-salts). In some cases it also contains a wetting agent and is encapsulated (fully or partially) in vapor permeable, but water impermeable materials. The ionic transfer layer will not freeze at temperatures as low as {minus}20 C ({minus}5 F), and provides sufficient space for all anode corrosion products, thus preventing undesirable stresses on the concrete, the anode assembly and any cosmetic covering.

Clear, K.C.

1999-07-01

389

Presentation of a reference material for the spatially resolved hydrogen analytics in near-surface layers by means of nuclear-reaction analysis  

International Nuclear Information System (INIS)

[en] The object of the thesis is the presentation of the theory of the 15N-reaction analysis (NRA), the experiemental construction of the corresponding beam pipe at the ion accelerator of the BAM and the evaluation of the measurement results. The aim is the first characterization of a reference material for the H analytics on the base of amorphous silicon (aSi) on a Si[100] substrate. The homogeneity of the aSi:H layers deposited by means of CVD was studied. For this pro substrate for about 30 samples the hydrogen depth profiles were measures, folded by means of a program created within the thesis and subjected to a statistical evaluation. The result were mean value ans standard deviation of the hydrogen concentration as well as an estimator for the contribution of the inhomogeneity to the measurement uncertainty. The stability of the potential reference material was proved by the constancy of result of repeated measurements of the hydrogen concentration during the application of a large dose of 15N ions. In an international ring experiment the reproducibility of the measurement results was proved. For the characterization of the aSi:H layers beside the NRA the white-light interferometry, ellipsometry, profilometry, and X-ray reflectometry, as well as the IR and Raman spectroscopy were used. The stoichiometry of the applied standard material kapton was checked by means of NMR spectroscopy and CHN analysis

2005-01-01

390

Polyimide as a versatile enabling material for microsystems fabrication: surface micromachining and electrodeposited nanowires integration  

Science.gov (United States)

The interest of using polyimide as a sacrificial and anchoring layer is demonstrated for post-processing surface micromachining and for the incorporation of metallic nanowires into microsystems. In addition to properties like a high planarization factor, a good resistance to most non-oxidizing acids and bases, and CMOS compatibility, polyimide can also be used as a mold for nanostructures after ion track-etching. Moreover, specific polyimide grades, such as PI-2611 from HD Microsystems™, involve a thermal expansion coefficient similar to silicon and low internal stress. The process developed in this study permits higher gaps compared to the state-of-the-art, limits stiction problems with the substrate and is adapted to various top-layer materials. Most metals, semiconductors or ceramics will not be affected by the oxygen plasma required for polyimide etching. Released structures with vertical gaps from one to several tens of ?m have been obtained, possibly using multiple layers of polyimide. Furthermore, patterned freestanding nanowires have been synthesized with diameters from 20 to 60?nm and up to 3??m in length. These results have been applied to the fabrication of two specific devices: a generic nanomechanical testing lab-on-chip platform and a miniaturized ionization sensor.

Walewyns, Thomas; Reckinger, Nicolas; Ryelandt, Sophie; Pardoen, Thomas; Raskin, Jean-Pierre; Francis, Laurent A.

2013-09-01

391

Finite Element Analysis in Combination with Perfectly Matched Layer to the Numerical Modeling of Acoustic Devices in Piezoelectric Materials  

Directory of Open Access Journals (Sweden)

Full Text Available The characterization of finite length Surface Acoustic Wave (SAW) and Bulk acoustic Wave (BAW) resonators is addressed here. The Finite Element Analysis (FEA) induces artificial wave reflections at the edges of the mesh. In fact, these ones do not contribute in practice to the corresponding experimental response. The Perfectly Matched Layer (PML) method, allows to suppress the boundary reflections. In this work, we first demonstrate the basis of PML adapted to FEA formalism. Next, the results of such a method are depicted allowing a discussion on the behavior of finite acoustic resonators.

Dbich Karim; Sylvain Ballandras; Thierry Laroche; Karl Wagner; Jean-Michel Brice; Xavier Perois

2013-01-01

392

Study of peptide on-line complexation with transition-metal ions generated from sacrificial electrodes in thin-chip polymer microsprays.  

UK PubMed Central (United Kingdom)

A miniaturized polymer electrospray-type interface is used to study metal-ion chelation with model peptides. Taking advantage of the intrinsic electrochemical behavior of electrospray, a sacrificial electrode is used to generate at the same time electrospray and transition-metal ions coming from the anodic dissolution of the electrode. The microspray interface provides enhanced mass transport due to its small dimensions, increasing the yield of possible reactions, in particular complex formation. Transition-metal electrodes, e.g. copper, zinc, nickel, iron and silver, are used to obtain on-line complexation with model peptides. It is demonstrated that the use of in-reservoir sacrificial electrodes is an efficient way to generate metal ions in order to form and study complexes with peptides, avoiding the addition of metallic salts.

Rohner TC; Girault HH

2005-01-01

393

Study of peptide on-line complexation with transition-metal ions generated from sacrificial electrodes in thin-chip polymer microsprays.  

Science.gov (United States)

A miniaturized polymer electrospray-type interface is used to study metal-ion chelation with model peptides. Taking advantage of the intrinsic electrochemical behavior of electrospray, a sacrificial electrode is used to generate at the same time electrospray and transition-metal ions coming from the anodic dissolution of the electrode. The microspray interface provides enhanced mass transport due to its small dimensions, increasing the yield of possible reactions, in particular complex formation. Transition-metal electrodes, e.g. copper, zinc, nickel, iron and silver, are used to obtain on-line complexation with model peptides. It is demonstrated that the use of in-reservoir sacrificial electrodes is an efficient way to generate metal ions in order to form and study complexes with peptides, avoiding the addition of metallic salts. PMID:15818723

Rohner, Tatiana C; Girault, Hubert H

2005-01-01