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Characterization of interfacial layer of ultrathin Zr silicate on Si(100) using spectroscopic ellipsometry and HRTEM

Characterization of interfacial layer of ultrathin Zr silicate on Si(100) using spectroscopic ellipsometry and HRTEM

The evident reduction of the interfacial layer due to the intentionally grown ultrathin oxynitride buffer layer was observed for the Zr silicate film deposited under a carefully designed growing condition. Any source of oxygen during the growth of the film results in the thicker, but self-limited interfacial layer. 䊚 2004 Elsevier B.V. All rights reserved.

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Investigation of the initial deposition steps and the interfacial layer of Atomic Layer Deposited (ALD) Al2O3 on Si

Investigation of the initial deposition steps and the interfacial layer of Atomic Layer Deposited (ALD) Al2O3 on Si

film. Although this oxidation was highly restricted for the H-terminated Si surface, the presence of Al on the surface catalyzes Si oxidation, and thus the interfacial layer formation. This oxidation could occur through the formation of SiOH groups during the island growth. These SiOH groups could be formed from the reaction of OH species on the de- posited islands with non-covered Si on the surface. SIMS results vali- dated the presence of SiOH groups in the interface, thus further con- solidating this assumption. Once the whole surface is covered by the ALD film, the interfacial oxide layer may continue to grow due to in- terdiffusion of O species through the layer. This interdiffusion has been assigned to bulk defect species, present in the form of AlOH, facilitating the oxygen diffusion.
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Electric interfacial layer of modified cellulose nanocrystals in aqueous electrolyte solution : predictions by the molecular theory of solvation

Electric interfacial layer of modified cellulose nanocrystals in aqueous electrolyte solution : predictions by the molecular theory of solvation

organization at the interface between the crystal surfaces and water for cellulose I β crystals surrounded by water (TIP3P model). An expansion of the unit cell and change in the cell angle to almost orthogonal observed during MD relaxation indicate a right-hand twist and a transition of the primary alcohol groups away from the starting TG conformation to GG in every other layer. In this conformation, interlayer hydrogen bonds form to the origin chains above and below. No change in the primary alcohol conformations or hydrogen-bonding patterns in the origin chain layers is observed. In the first hydration layer, a strong localization of the adjacent water is found that extends far into the solution. It is hypothesized that the structured water layers might present a barrier to the approach of cellulase enzymes toward the cellulose surfaces in enzyme-catalyzed hydrolysis and inhibit the escape of soluble products, contributing to the slow rates of hydrolysis observed experimentally. 26
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Enhancing oxygen reduction reaction of YSZ/La2NiO4+δ using an ultrathin La2NiO4+δ interfacial layer

Enhancing oxygen reduction reaction of YSZ/La2NiO4+δ using an ultrathin La2NiO4+δ interfacial layer

Recently, the family of compounds A2MO4 + o with the K2NiF4 type structure has attracted more attention as alternative cathode materials for intermediate temperature SOFCs (IT SOFCs) ( 8 , 9 ] due to their high electronic conductivity, thermal expansion coefficients (TECs) dose to the solid electrolyte, high electrocatalytic activity, and some oxygen overstoichiometry which enhanœs the oxygen ionic conduction ( 10-13 ]. Among those materials, La2NiO4+ô has shown a wide range of oxygen overstoichiometry and presents one of the highest oxygen diffusion values ( 14 ]. The structure of La2NiO4+o is built of alternative rock sait La2O2 and perovskite NiO2 layers, and can contain a significant oxygen excess ( 14-17 ]. The ionic transport takes place through diffusion phenomena of inter stitial ions in the vacanàes in the perovskite layers and the rock sait layer ( 8 , 18 ] .
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PEAI-Based Interfacial Layer for High-Efficiency and Stable Solar Cells Based on a MACl-Mediated Grown FA 0.94 MA 0.06 PbI 3 Perovskite

PEAI-Based Interfacial Layer for High-Efficiency and Stable Solar Cells Based on a MACl-Mediated Grown FA 0.94 MA 0.06 PbI 3 Perovskite

2 and near the perovskite/HTL interface in perovskite solar cells (PSCs). It is shown to boost their maximum power conversion efficiency (PCE) from 20.37% to 22.18% while the hysteresis becomes negligible. A comprehensive study of the device electrical response has been performed. The electrical impedance spectroscopy (EIS) measurements have been fitted with ad-hoc equivalent electrical circuits. The electrical responses due to interface stabilization, the intrinsic dielectric relaxation of the perovskite, the charge depletion and charge recombinations have been distinguished. The low frequency capacitance is analyzed as a charge recombination capacitance. The perovskite surface buffer layer is notably shown to supress charge recombinations from the boosting of the high frequency and low frequency recombination resistances as well as from the marked decrease of the low frequency recombination capacitance. The prepared devices are proved especially resistant to electrical stresses, to light irradiation and to moisture.
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Enhancing oxygen reduction reaction of YSZ/La2NiO4+δ using an ultrathin La2NiO4+δ interfacial layer

Enhancing oxygen reduction reaction of YSZ/La2NiO4+δ using an ultrathin La2NiO4+δ interfacial layer

On the other hand, the sol employed for the ultrathin layer deposited by dip coating corresponding to La 2 NiO 4þ d phase is prepared by using a polymeric route similar to this outlined by Pechini [ 25 ]. Pure metal nitrates, La(NO 3 ) $6H 2 O and Ni(NO 3 ) 2 $6H 2 O are used as starting salts. They are dissolved in water in stoichiometric amounts [ 26 ]. The solution was mixed to an organic solution of hexamethylenetetramine and acetyl acetone with a molar ratio (1:1), in acetic acid. Therefore, a range of molar ratio of complexing agent to nitrate species (called R) has been de fined. Pure phase is obtained for R ratio ranging from 2 to 3. The resulting solution was then stirred and heated in air at 70  C until
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Computational evaluation of interfacial fracture toughness of thin coatings

Computational evaluation of interfacial fracture toughness of thin coatings

Since the traditional methods of developing protective coatings through trial- and-error experimentation are time-consuming and costly, extensive modelling and simulation efforts are underway to speed up these developments. However, the materials data needed for the computer models are not easily available. In particular, limited experimental data exist on the fracture toughness of thin films and there are virtually no data on interfacial fracture toughness for thin multi- layer coatings. Therefore, developing computational methods that could allow an evaluation of fracture properties of candidate erosion materials would benefit both experimental and modelling efforts.
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The Abstract MAC Layer

The Abstract MAC Layer

and ack(m) i , where m is a message from some fixed alphabet. The abort is used in cases where the sender is satisfied that “enough” neighbors have already received the message, and so is willing to terminate efforts by the MAC layer to continuing broadcasting. Though real world MAC layers do not usually include an abort functionality, it seems both useful and feasible to implement, so we include it in our interface. As mentioned, the abstract MAC layer automaton connects to the network through the physical layer interface. It might also receive the network’s location and time outputs. In Section 2.2, we describe the properties an abstract MAC layer automaton composed with a network automaton must satisfy to be considered an abstract MAC layer service.
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The Abstract MAC Layer

The Abstract MAC Layer

A diversity of possible communication assumptions complicates the study of algorithms and lower bounds for radio networks. We address this problem by defining an Abstract MAC Layer. This service provides reliable local broadcast communication, with timing guarantees stated in terms of a collection of abstract delay functions applied to the relevant contention. Algorithm designers can analyze their algorithms in terms of these functions, independently of specific channel behavior. Concrete implementations of the Abstract MAC Layer over basic radio net- work models generate concrete definitions for these delay functions, automatically adapting bounds proven for the abstract service to bounds for the specific radio network under consider- ation. To illustrate this approach, we use the Abstract MAC Layer to study the new problem of Multi-Message Broadcast, a generalization of standard single-message broadcast, in which any number of messages arrive at any processes at any times. We present and analyze two algorithms for Multi-Message Broadcast in static networks: a simple greedy algorithm and one that uses regional leaders. We indicate how these results can be extended to mobile networks.
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The abstract MAC layer

The abstract MAC layer

This approach generates many interesting open questions. For example, ex- ploring how we can use the layer to implement basic primitives such as neighbor discovery and unicast communication, or complex protocols such as spanning trees and dominating sets. Extensions to the MMB problem, such as calculat- ing throughput bounds and the cost of sender acks, are also important. Another direction is to improve the abstract MAC layer formalism itself. We might gener- alize the G and G ′ model to capture the effects of signal to interference-plus-noise ratios (SINR), or perhaps replace the deterministic delay functions with proba- bility distributions over the different possible delays. This latter change would support more advanced analysis of the system’s probabilistic behavior. Finally, it will prove useful to analyze specific MAC layer strategies for specific radio network models, providing concrete definitions for the delay functions.
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The Abstract MAC Layer

The Abstract MAC Layer

For the case where G 6= G ′ , similar techniques can provide a good starting point. Recent work, however, indicates that care must be taken and new strategies and/or assumptions might by required [26, 9, 28]. This remains an interesting direction for future work. For simplicity, in this paper we assume that the abstract MAC Layer properties hold “with high probability,” but do not expose the specific probabilities as parameters of the implementation. As indicated by our example implementations from above, these probabilities, though high, can be non-trivially distinct from 1. For some analyses it might prove useful to make use of the specific probabilities. As mentioned in Section 8, there is ongoing work that considers this generalization of the model, and uses it to obtain more precise probabilistic bounds on the broadcast problem.
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Calculation of the long range interactions for interfacial properties

Calculation of the long range interactions for interfacial properties

∆r r c < r iajb < r c + ∆r 0 r iajb ≥ r c + ∆r (16) where ∆r is equal to 0.05 Å for a cutoff of 12 Å. In the most cases, the MD simulations used a truncated force and the MC simulations a truncated potential. Figure 2 shows the profiles of the normal p N and tangential p T components of the pressure tensor calculated from MC and MD configurations. For a planar surface, the mechanical equilibrium requires to have p N (z) and p T (z) constant and equal to p in the bulk phases. In the interfacial re- gion, p T exhibits two negative peaks indicating that the liquid phase is under tension. The normal and tangential components of the pressure calculated from MD are shown in Figure 2a. These profiles establish the mechanical equilibrium of these MD configurations as expected for a method that uses the forces to generate the evolution of the system. On the other hand, in MC configurations when the forces are calculated from Eq.(15), the profiles of p N and p T highlight that the configurations are not in mechanical equilibrium. This can be explained by the fact that MC uses the configurational energy to generate the configurations and that the pressure is calculated from the derivative of the configurational 6
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2014 — Conception d'un revêtement bioactif pour implant cardiovasculaire par la méthode du layer-by-layer

2014 — Conception d'un revêtement bioactif pour implant cardiovasculaire par la méthode du layer-by-layer

Pour ce faire, tel que détaillé dans la revue de littérature (section 1.4.1), des molécules d’intérêt pour la fabrication d’un tel film ont été ciblées : le CS, le CHI, le COL ainsi qu[r]

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Interfacial damage and load transfermodeling in short fiber reinforced composites

Interfacial damage and load transfermodeling in short fiber reinforced composites

Three main key-points have been integrated to this approach: an original damage evolution law at the interface, an appropriate load transfer law at the matrix-fiber interface, and a homogenization strategy founded on the generalized Mori-Tanaka scheme. The damage evolution law is driven by a local prob- abilistic criterion based on the interfacial stress field estimation. This type of evolution depends on the maximal local damage rate at the fiber /matrix interface, determined from a numerical evaluation at several points of the interface surrounding the inclusion. It is then coupled with a load transfer law formulated according to a modified shear lag model (SLM). The developed model is assessed with a finite element (FE) computation integrating cohesive elements at the matrix-fiber interface. The FE unit cell consists in a periodic media (hexagonal array) with periodic boundary conditions. The fiber- matrix interface integrates cohesive elements, with a cohesive law driven by a Paulino-Park-Roesler (PPR) potential-based formulation. The latter has been proven to be suitable for the 3D modeling of interface in reinforced composites. The proposed approach is able to accurately capture the non-linear behavior of short fiber reinforced polyamide composites accounting for interfacial damage.
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Interfacial Reaction during Friction Stir Welding of Al and Cu

Interfacial Reaction during Friction Stir Welding of Al and Cu

IV. CONCLUSIONS A 1050 aluminum alloy was successfully welded to commercially pure copper by friction stir welding. The pin tool was located exclusively on the Al side, and there was no mixing of either material through the weld. The bonding results only from reactive interdiffusion; therefore, this process is named friction stir diffusion bonding. The reactive interdiffusion of Al and Cu gives rise to the formation of a very thin layer of intermetallic compounds at the Al/Cu interface (about 200 nm only). Extensive microstructure analyses by TEM indicate that this layer was formed after the stirring action of the tool pin (i.e., once the pin tool left). Two intermetallics compounds were detected, namely, the Al 2 Cu (h) and
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Influence of isothermal aging conditions on APS TBC's interfacial fracture toughness

Influence of isothermal aging conditions on APS TBC's interfacial fracture toughness

4. Conclusion Interfacial indentation has been employed to address interfacial ad- hesion and derive interfacial toughness in TBC (thermal barrier coat- ings) systems produced by Atmospheric Plasma Spray technique, after various isothermal aging, in the temperature range 1050 °C–1100 °C and holding times from 100 to 300 h. As compared to the as-deposited, unaged TBC, it is shown that the toughness degrades with both the ox- idation time and temperature, remarkably decreasing quasi-linearly with the thickness of the TGO (thermally grown oxide) that develops upon holding at high temperature. Typically for APS processed TBC, the TGO is a multi-scale oxide composed of successive layers of Al 2 O 3
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Contact of rough surfaces in presence of interfacial fluid flow

Contact of rough surfaces in presence of interfacial fluid flow

[8] Andrei G. Shvarts. Coupling mechanical frictional contact with interfacial fluid flow at small and large scales. PhD thesis, PSL Research University, MINES ParisTech, 2019. [9] Y. Z. Hu and K. Tonder. Simulation of 3-D random rough surface by 2-D digital filter and fourier analysis. Int J Mach Tool Manu, 32 :83–90, 1992.

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Belief layer for Haystack

Belief layer for Haystack

Finally, the belief service should have a sensible user interface that would allow future developers of Haystack, as well as potential end-users, to experiment wit[r]

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Interfacial analysis of n-ALKANETHIOL SAMs on GaAs(001) by ARXPS

Interfacial analysis of n-ALKANETHIOL SAMs on GaAs(001) by ARXPS

Archives des publications du CNRC For the publisher’s version, please access the DOI link below./ Pour consulter la version de l’éditeur, utilisez le lien DOI ci-dessous. Access and use of this website and the material on it are subject to the Terms and Conditions set forth at Interfacial analysis of n-ALKANETHIOL SAMs on GaAs(001) by ARXPS

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Interfacial damage and load transfermodeling in short fiber reinforced composites

Interfacial damage and load transfermodeling in short fiber reinforced composites

2. Experimental observation of interfacial damage in a SFRC Short glass fibers reinforced polyamide-66 damage mechanicms has been severaly characterised in situ under quasistatic monotonic loading. Arif et al. [13] have proposed a damage scenarios depending on the relative humidity (RH). 1) the damage starts where local stress are highest which is most of the time localised at the fiber ends (Fig. 1b). 2) interfacial decohesion propagates along the fiber interface (Fig. 1a). 3) matrix microcracks develop and propagate in various way depending on the RH. 4) accumulation of microcracks leads to failure of the material.
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