Diffusion Barrier

rate from YDC layer is limited by oxygen diffusion rate from ZDC layer. When the pumping rate of the YDC solid electrolyte is limited by the oxygen diffusion rate of the ZDC dense diffusion barrier and the voltage increases to a certain value, the limiting current plateau is obtained. Initial voltage is positively related to oxygen concentration, which is consistent with phenomenon of other studies [20, 21].

this theory was derived for reactions in the gas phase, and the pre-exponential corresponds to the number of molecular trials needed to overcome the barrier (number of ‘hits’). In condensed phase, this value is replaced by a more complex relationship. another possible approach to model the pathway through the channel would be to apply a force to the antibiotic molecule and to drag it through the channel. For both methods, the pathway, possible electrostatic interactions and interaction with the channel can be obtained. However, the measured per- meation values are obtained from modelling indirectly through an extrapolation into the experimentally avail- able millisecond range, and thus any conclusions must be treated with caution.

The objective of this study is to identify the crystal structure of the various phases in the Cr-Nb-Re coating system by means of TEM. The paper will describe details of the selected area electron diffraction (SAED) patterns involving crystal structure and lattice constant analysis of the Cr-Nb-Re coating system. In the absence of other exper- imental data, this study will offer guidelines for developing Re-based diffusion barrier coatings on Nb or Nb-based alloys.

Carriers in a solar cell are typically collected by means of a simple p-n junction. The traditional structure of c-Si solar cells favors a thin n-type layer, called the emitter and a thick p-type layer, called the base. When a p-type semiconductor layer is in contact with an n-type semiconductor layer majority carriers of each will diffuse into the other. When this occurs, fixed, ionized donor and acceptor atoms are left behind. As the diffusion continues a built-in electric field is formed at the junction between the layers. The current associated with this field is called the drift current. The force associated with this field opposes the diffusion of carriers and equilibrium between the two is reached. The region around the junction that contains this electric field is known as the depletion, or space charge, region (SCR) since the electric field sweeps charged carriers out of this region.

When this de-plating the it current constant layer is less than the in figure 4.4, giving lesser thickness than that electrolytic solution The is thus causing under plating of wafer and [r]

The innovation of electronic bidet seat toilet in Japan has diffused to more than sixty percent of Japanese household while it has low rate of diffusion in other countries especially in developing country. From this phenomenon, it is interesting to understand about the barrier of diffusion, which focuses on the adopter categories of diffusion, barrier factors and proposition of key success factors of the diffusion in Indonesia as one of emerging economic and the member of G 20. There have been few studies about diffusion of innovation toilet, and this paper especially examines the diffusion of new innovations on electronic bidet toilet due to its successful diffusion among Japanese household, and further became a standard fixture toilet in Japan. This paper also discusses the product life cycle of electronic bidet toilet in Japan, global diffusion, identifies adopter categories and barrier factors of diffusion in Indonesia. Finally, theoretical propositions are developed on the diffusion of innovation for electronic bidet toilet in Indonesia.

PbTe-based thermoelectric materials are good candidates for harvesting waste heat at mid-range temperatures due to their high thermoelectric efficiencies. Excellent quality and reliability of the bonding between the thermoelectric material and the electrode at high temperatures are essential for manufacturing thermoelectric generators. Here, a technique has been developed to achieve high- quality bonding between PbTe and the electrode. We have successfully performed one-step sintering of nickel electrode to n-type PbTe powder using spark plasma sintering. The fabricated interphase, composed of nickel telluride, is continuous and homogeneous across the junction, without visible flaws on the electrode or in the interphase and PbTe. To evaluate the long-term thermal stability of the fabricated bond, an aging test was conducted at 823 K for 360 hours under vacuum. The microstructures and chemical composition of the fabricated bonding and the aged sample were investigated in detail by scanning electron microscopy equipped with energy dispersive X-ray spectroscopy analysis. No excess reaction was observed between the electrode and the thermoelectric material after aging, supporting the formation of a chemically stable interphase, which acts as a diffusion barrier. Degradation of the PbTe was detected after aging, however. The fabricated interface meets the required criteria for maximum efficiency of PbTe materials.

Extracellular ionic homeostasis in an insect central nervous system involves a peripheral intercellular diffusion barrier, an extracellular matrix and neuroglial cation transport.. The p[r]

The selection of the support is of critical importance in the preparation of thin (< 5 μm) and defect-free palladium membranes. High surface roughness and the presence of large pores inhibit the deposition of thin palladium films. Asymmetric porous ceramic supports, having a gradual decrease in pore size from the bulk to the top layer, have a good surface quality to support very thin Pd-based films. However, they lack mechanical strength. Currently, the ceramic supports that are commercially available are asymmetric tubes and capillaries/hollow fibres. For example, Inopor produces ceramic tubular supports of different ceramic materials and pore sizes (http://www.inopor.com/). Metallic supports are more robust than ceramic ones, but the commercially available metallic supports, mainly tubular, have large and non-uniform pores and the surface has a rather low quality hindering their direct use as support for very thin Pd films. GKN (http://www.gkn-filters.de/), Pall (http://www.pall.com) and Mott (http://www.mottcorp.com/) are the main metallic support suppliers. In the case of membranes in which both the selective layer and the support are metallic and are operated above the Tamman temperature (half the melting point in absolute temperatures), interdiffusion of both metals occur, reducing the permeation performance of the membrane [26]. To solve this problem and to improve the quality of the surface, an inter-metallic diffusion barrier layer between the metallic support and the metallic selective layer is deposited.

Therefore, porosity and surface area play an important role in peptide release. However, at close to 12 hours, system 1 (with- out adsorbed nanoparticles) had released 90.3% ± 9.1% of the peptide, whereas systems 2, 3, 4, and 5 (with adsorbed nano- particles) had released only 36.1% ± 5.2%, 29.4% ± 3.2%, 22.2% ± 4.6%, and 19.8% ± 3.2%, respectively (see Figure 8). A higher release rate was found in the systems that contained a more discontinuous nanoparticle film on the microsphere surfaces, which may be due to the nanoparticle–leuprolide– microsphere interactions generated during the assembly process, and to the continuity in the nanoparticle film, which appears to create a diffusion barrier and induce changes in the release rate. Thus, a controlled release is achieved when nano- particles are adsorbed onto the porous microsphere surface (systems 2–5). Consequently, if the amount of nanoparticles increases, the release rate slows; this phenomenon could be explained by leuprolide entrapment between the surfaces and the nanoparticle film.

unstirred water layer was resolved into two compartments: one behaves like a layer of water overlying the upper villi while the other probably consists of solution between villi. The superficial layer is physiologically most important during uptake of highly permeant compounds and varies in thickness from 115 to 334 µm as the rate of mixing of the bulk mucosal solution is varied. From data derived from a probe molecule whose uptake was limited by the unstirred layer, the effective surface area of this diffusion barrier also was determined to vary with stirring rate and equaled only 2.4 cm 2 ·100 mg -1 in the unstirred condition but increased to 11.3 cm 2 ·100 mg -1 with vigorous mixing. This latter value, however, was still only 1/170 of the anatomical area of the microvillus membrane. With these values, uptake rates for a number of passively absorbed probe molecules were corrected for unstirred layer resistance, and these data were used to calculate the

The electroplating nickel layer as diffusion barrier for the copper metallization in silicon solar cells investigated in this work includes nickel deposited by electroless method, silicidation, nickel, and copper deposited by electroplating. Electroplating takes place by means of an applied electric field between anode and cathode. This makes metal ions migrating to the cathode surface and reducing to form metal layers. However, silicon is a semiconductor. Prior to electroplating copper (or nickel), a seed layer of copper needs to be deposited first to conduct the electroplating current. Electroless plating is suited as a method of deposition for the seed layer. Electroless plating techniques do not need electrical currents. A conducting surface and anode electrode do not need to achieve deposition. Electroless nickel plating can be used as the copper seed layer. The use of electroless Ni makes it possible for nickel metal (seed layer) to be plate on solar cells made with silicon. Electroless nickel deposition is an autocatalytic process, which uses a substrate immersed in a plating bath that contains metal source ions (cations) and a reducing agent. The cations can capture electrons, which is provided by a reducing agent in the solution; and is absorbed on the substrate surface. After electroless nickel deposition, the deposited samples will be heated in the ambiance of Ar/H 2 or N 2 gas to form the alloys

The findings show very light corrosion damage caused at elevated temperature under dry conditions. Weight loss was not recorded and only weight gain to the fuel up to a level of 1000 ppm does not affect negatively the behavior of the tested metals. This is related to the diffusion barrier formed on the surface during exposure to the sure to the steam boiler flue gas environment, all the tested metals behaved similarly indicating mutual factor determining the results. The main parameter affecting the results is the deposition of a protective layer creating a diffusion barrier which ibits the corrosion process. When calcium salts were added as chloride or bromide the deposited layers were composed of various crystalline main Fe 3 O 4 , CaSO 4 , CaO,

Large-scale first-principles density functional theory calculations are performed to investigate the adsorption and diffusion of Ru adatoms on monolayer graphene (G) supported on Ru(0001). The G sheet exhibits a periodic moiré-cell superstructure due to lattice mismatch. Within a moirécell, there are three distinct regions: fcc, hcp, and mound, in which the C6-ring center is above a fcc site, a hcp site, and a surface Ru atom of Ru(0001), respectively. The adsorption energy of a Ru adatom is evaluated at specific sites in these distinct regions. We find the strongest binding at an adsorption site above a C atom in the fcc region, next strongest in the hcp region, then the fcc-hcp boundary (ridge) between these regions, and the weakest binding in the mound region. Behavior is similar to that observed from small-unit-cell calculations of Habenicht et al. [Top. Catal. 57, 69 (2014)], which differ from previous large-scale calculations. We determine the minimum-energy path for local diffusion near the center of the fcc region and obtain a localdiffusion barrier of ∼ 0.48 eV. We also estimate a significantly lower local diffusion barrier in the ridge region. These barriers and information on the adsorption energy variation facilitate development of a realistic model for the global potential energy surface for Ru adatoms. This in turn enables simulation studies elucidating diffusion-mediated directed-assembly of Ru nanoclusters during deposition of Ru on G/Ru(0001).

While the steel sheet as a diffusion barrier has only a small effect on the temperature distributions, its effect on pore pressures is substantial. This is clearly seen in Fig- ure 4. In case A1, where the transfer of water and water vapour through edge 1 is blocked, the whole amount of free water and water vapour is pushed by the temperature and pore pressure gradients towards edge 2. This is de- picted in Figure 5, showing the distribution of free water content over the cross-section at various instants. Beyond 200ºC the chemically bounded water starts releasing and further increases the volume of free water (Figure 5(a)). At some point a full saturation of pores takes place which causes the substantial rise of the pore pressure. This is more pronounced in case A1, where the magni- tude of pore pressure at 30 min is about 4.5 MPa and is

In electroplating metallisation, copper is used as a diffusion barrier for zinc. To also take advantage of the positive corrosion properties of aluminium on the brass substrates observed in this work, copper-aluminium alloy coatings were produced as a logical consequence to improve the diffusion barrier and corrosion barrier behaviour. Technical bulk copper-aluminium alloys [42] show an optimum combination o f high corrosion resistance in many aggressive media with mechanical properties above average compared to other copper based alloys [93]. Table 6.4 gives an overview on internationally available CuAl alloys. It should be mentioned, that copper-aluminium alloys can not be deposited by electroplating. For PVD this limitation does not exist of course. Nonetheless no PVD data have been published up to now, surprisingly. The high corrosion resistance can be explained by the oxide film on the surface, which is mainly aluminium oxide AI2O3 with some copper oxide. The corrosion behaviour is dependant on the structural constitution.

The 3D-ASL was a pseudo-continuous arterial spin- labeling sequence using 3D segmented spiral readouts with the post-label delay time of 1.525 s. The multi-b DWI, a diffusion-weighted echo-planar sequence, was implemented with a single shot spin-echo using 13 dif- ferent b-values (0, 30, 50, 100, 200, 300, 500, 800, 1000, 1500, 2000, 3000, 3500 s/mm 2 ) in 3 orthogonal directions as described in our previous study. 15 The DCE-MRI was performed with a 50-phase dynamic gradient-echo T 1 scanning and each phase was 4 s.

Evaporation produces salinities at the coast of the GBR lagoon that can be roughly 1 ppt higher than normal seawater values (Walker 1981, 1982). During the dry season, when fresh- water river inflow is negligible, the magnitude of the salinity elevation is dependent on the evaporation rate, and the degree of mixing with water from the Coral Sea. By using extensive mea- surements of the along and across-shelf salinity, and evaporation rates, it is possible to calculate the flushing time and large-scale diffusion coefficients of water in GBR lagoon. Confining the analysis to the dry season simplifies the analysis considerably because during the wet season a detailed knowledge of highly variable river discharges would be required to accurately calcu- late the salinity budget. Although the calculations of flushing time make use of the salinity data taken from the dry season, it is most likely that the flushing times in the wet season are simi- lar, because with the exception of baroclinic flows, the physical processes of water movement and exchange with the Coral Sea are similar in the dry and wet seasons.

where t is an interpolation parameter ranging from 0 to 1 that controls the position of the diffusing oxygen atom. The total energy of each image is minimized with respect to relaxation of all atoms within a given radius of the diffusing oxygen atom (with the diffusing atom held fixed). This approach is adopted to allow us to focus on the barrier to diffusion for a single oxygen atom. If unconstrained optimization is employed oxygen diffusion can trigger displacement of remote oxygen ions which complicates the analysis. We tested a range of constraint radii from 2 to 7 Å and find 4 Å provides a good compromise between capturing local distortions associated with oxygen diffusion while minimizing effects on oxygen ions further away. The interpolation is performed using the vasp Transition State Tools (VTST) script. 37

The penetration of PI into the stele was used to assess the function of apoplastic diffusion barriers in roots [S14]. The seedlings were incubated in a fresh solution of 15 µM (10 µg mL -1 ) PI in the dark for the period indicated in the figure legend (3, 5, 7, and 20 min), and rinsed twice with water. Fluorol yellow 088 staining was used to detect suberin accumulation in roots [S15]. For quantification of the number of endodermal cells, the onset of elongation was defined as the endodermal cell whose median optical section was more than twice in width [S14]. Lignin autofluorescence of cleared roots was used to observe the Casparian strip deposition [S14]. The 5- or 6-day-old seedlings (as stated in figure legends) were used to observe Casparian strip autofluorescence, suberin lamella stained with fluorol yellow 088, PI permeability, GFP and mCherry fluorescence. The fluorescence was observed using confocal microscopy FV1000 (Olympus). The excitation and emission wavelengths were set as follows: 488 nm and 485–545 nm for Casparian strip autofluorescence, fluorol yellow 088 and GFP; 559 nm and 570–670 nm for PI and mCherry. The z-stack and radial optical section images were constructed with a successive series of 1-µm step-size images with Fiji (http://fiji.sc/Fiji). The signal of PIN1-GFP is observed with Confocal microscopy. All the experiments were reproduced in different trials.