Results 1 - 10 of 23984
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[en] The process of trench formation in photo-electrochemical etching of n-type Si (1 0 0) has been studied as dependent on the normalized etching current density j/jPS and on the line seed period a. Experiments were performed on n-type Si (1 0 0) samples with resistivity ρ = 5 and 15 Ω cm. V-shaped grooves with a period a = 4–13 µm, fabricated on the sample surface, were used as etch seeds. We formulate criteria for macropores merging into trenches and formation of trenches from double-pore rows. The validity of these criteria is confirmed by experimental data. The relationships obtained are based on the tendency of the system to form macropores of a certain diameter d, characteristic of silicon with a given resistivity. We found reasons for the enhanced irregularity of the trench walls and suggest design rules for periodic structures. To obtain a wall array, it is recommended to choose a period that does not differ significantly from the average distance between discrete self-organized macropores, a ≈ ā, and an etching current density within the range πd/4a < j/jPS < 2d/a
[en] The microstructure and corrosion behaviors of Mg-3Nd alloy without and with Al addition were characterized in the present work. The experimental results show that the microstructure of Mg-3Nd alloy is significantly refined by Al addition. There are two kinds of precipitated phases in the alloy with Al addition, which are Al11Nd3 phase and Al2Nd phase. With increasing the Al addition, the E corr increases and the I corr decreases in Mg-3Nd alloy. The average immersion corrosion rate of Mg-3Nd alloy without Al addition is lower than that of Mg-3Nd alloy with 1% and 2% Al, but higher than that of Mg-3Nd alloy with 3% Al. When the Al content was 3%, the corrosion potential is −1.482 V, corrosion current density is 6.93 μA/cm2 and the corrosion rate is 0.69 mg cm−2·day−1. The Mg-3Nd alloy without Al addition have a high frequency and a low frequency capacitive loop. The Mg-3Nd alloy with 1% and 2% Al has only a high frequency capacitive loop. When the Al addition is 3%, there are one high frequency capacitive loop and one low frequency inductive loop. The corrosion mechanism is different for Mg-3Nd alloy with increasing the Al addition. (paper)
[en] Positive polarity regime of microsecond plasma opening switch (MPOS) was investigated at the DOUBLE generator (480 kV, 300 kA, 1.3 μs). The measurements of the ion flow parameters showed the considerable enhancement of the ion current density over the thermal flow in the conduction phase. Ion losses reached more than 80% of the full energy losses in MPOS operating on the inductive load
[en] The transport properties of NSTX plasmas obtained during the 2008 experimental campaign have been studied and are reported here. Transport trends and dependences have been isolated, and it is found that both electron and ion energy transport coefficients have strong dependences on local values of n(del)T, which in turn is strongly dependent on local current density profile. Without identifying this dependence, it is difficult to identify others, such as the dependence of transport coefficients on Bp (or q), Ip and Pheat. In addition, a comparison between discharges with and without Lithium wall conditioning has been made. While the trends in the two sets of data are similar, the thermal transport loss, especially in the electron channel, is found to strongly depend on the amount of Lithium deposited, decreasing by up to 50% of its no-Lithium value.
[en] The benefits of multi-layer graphene (MLG) capping on Cu interconnects have been experimentally demonstrated. The resistance of MLG capped Cu wires improved by 2–7% compared to Cu wires. The breakdown current density increased by 18%, suggesting that the MLG can act as an excellent capping material for Cu interconnects, improving the reliability characteristics. With a proper process optimization, MLG capped Cu interconnects could become a promising technology for high density back end-of-line interconnects. (paper)
[en] All investigations of electrochemical reactors with gas-evolving electrodes must take account of the fact that the actual current density controlling cell operation commonly differs substantially from the nominal current density used for practical purposes. Both quantities are interrelated by the fractional bubble coverage. This parameter is shown to be affected by a large number of operational quantities. However, available relationships of the bubble coverage take account only of the nominal current density. A further essential insufficiency is their inconsistency with reality for very large values of the bubble coverage being of relevance for operation conditions leading to anode effects. An improved relationship applicable to the total range is proposed.
[en] The interaction of a current-driven domain wall with an anisotropy boundary in nanowires with perpendicular magnetic anisotropy is investigated. A local reduction of the anisotropy constant is used to create an artificial boundary where the domain wall gets pinned. Micromagnetic simulations and analytical calculations, based on a one-dimensional model, are employed to describe the interaction of the domain wall and the anisotropy boundary and to determine the depinning current densities. Two different pinning regimes—an intrinsic and an extrinsic—can be identified in dependence with the characteristic of the boundary. A very good agreement between simulated and analytically obtained data is achieved. (paper)
[en] Taking into consideration the importance of the anodic effect in the technological process of tantalum elctrowinning, the authors studies the influence of Ta2O5 and K2TaF7 on the critical anodic current density. The Ta2O5 has a beneficial effect, increasing this current density. K2TaF7 acts indirectly, by increasing the Ta2O5 solubility in the electrolyte. These effects are evident in the current-voltage curves obtained for different K2TaF7 and Ta2O5 concentrations. (author)
[pt]Determina-se a influencia dos teores do oxido de tantalo, Ta2O5 e do heptafluotantalato dipotassio, K2TaF7 na densidade de corrente anodica cutica durante a eletrorrecuperacao de tantalo a 7000C, utilizando uma mistura eutetica de fluoretos de litio, sodio e potassio como solvente para o K2TaF7 e eventualmente Ta2O5. (autor)