55 research outputs found
Improved conductivity of aluminum-doped ZnO : the effect of hydrogen diffusion from a hydrogenated amorphous silicon capping layer
Plasma-deposited aluminum-doped ZnO (ZnO:Al) demonstrated a resistivity gradient as function of the film thickness, extending up to about 600¿nm. This gradient decreased sharply when the ZnO:Al was capped by a hydrogenated amorphous silicon layer (a-Si:H) and subsequently treated according to the solid phase crystallization (SPC) procedure at 600¿°C. The resistivity reduced from 1.2¿·¿10-1 to 2.6¿·¿10-3 O¿·¿cm for a film thickness of 130¿nm, while for thicker films the decrease in resistivity was less pronounced, i.e., a factor of 2 for a film thickness of 810¿nm. While the carrier concentration was not affected, the mobility significantly increased from 7 to 30 cm2/V¿·¿s for the thick ZnO:Al layers. This increase was ascribed to the passivation of grain boundary defects by hydrogen, which diffused from the a-Si:H toward the ZnO:Al during the SPC procedure. The passivation effect was more pronounced in thinner ZnO:Al layers, characterized by a smaller grain size, due to the presence of large grain boundaries. For thicker films with grain sizes up to 200–300¿nm the mobility became progressively less affected by the presence of grain boundaries. Therefore, the hydrogen-induced improvement in conductivity was less significant for the thick ZnO:Al film
Experimental evidence of two-band behavior of MgB2
The break-junction tunneling has been systematically investigated in MgB2.
Two types of the break-junction contacts have been exploited on the same
samples, which demonstrated tunnel contact like (SIS) and point contact like
(SnS) behavior. Both of them have shown the existence of the two distinct
energy gaps. We have observed also the peculiarities on the I(V)-
characteristics related to Leggett's collective mode assisted tunneling. -->
Corresponding author address: [email protected]: 14 pages, 6 figures, 1 table; corrected typos and fig
A framework for analysis of linear ultrasound videos to detect fetal presentation and heartbeat.
Confirmation of pregnancy viability (presence of fetal cardiac activity) and diagnosis of fetal presentation (head or buttock in the maternal pelvis) are the first essential components of ultrasound assessment in obstetrics. The former is useful in assessing the presence of an on-going pregnancy and the latter is essential for labour management. We propose an automated framework for detection of fetal presentation and heartbeat from a predefined free-hand ultrasound sweep of the maternal abdomen. Our method exploits the presence of key anatomical sonographic image patterns in carefully designed scanning protocols to develop, for the first time, an automated framework allowing novice sonographers to detect fetal breech presentation and heartbeat from an ultrasound sweep. The framework consists of a classification regime for a frame by frame categorization of each 2D slice of the video. The classification scores are then regularized through a conditional random field model, taking into account the temporal relationship between the video frames. Subsequently, if consecutive frames of the fetal heart are detected, a kernelized linear dynamical model is used to identify whether a heartbeat can be detected in the sequence. In a dataset of 323 predefined free-hand videos, covering the mother's abdomen in a straight sweep, the fetal skull, abdomen, and heart were detected with a mean classification accuracy of 83.4%. Furthermore, for the detection of the heartbeat an overall classification accuracy of 93.1% was achieved
Cubic Vertices for Symmetric Higher-Spin Gauge Fields in
Cubic vertices for symmetric higher-spin gauge fields of integer spins in
are analyzed. generalization of the previously known action
in , that describes cubic interactions of symmetric massless fields of
all integer spins , is found. A new cohomological formalism for the
analysis of vertices of higher-spin fields of any symmetry and/or order of
nonlinearity is proposed within the frame-like approach. Using examples of
spins two and three it is demonstrated how nontrivial vertices in ,
including Einstein cubic vertex, can result from the deformation of
trivial Minkowski vertices. A set of higher-derivative cubic vertices for any
three bosonic fields of spins is proposed, which is conjectured to
describe all vertices in that can be constructed in terms of connection
one-forms and curvature two-forms of symmetric higher-spin fields. A problem of
reconstruction of a full nonlinear action starting from known unfolded
equations is discussed. It is shown that the normalization of free higher-spin
gauge fields compatible with the flat limit relates the noncommutativity
parameter of the higher-spin algebra to the radius.Comment: 78 pages. V2: typos corrected, coefficients in sections 5.1 and 6.3
corrected and undetermined coefficients of the supertrace of higher-spin
algebra in section 6.1 and of the relation between tensor and generating
function formalism in section 7.3 are computed. Clarifications, graphs,
references and acknowledgments added. V3: typos corrected, reference added,
the version to appear in Nucl.Phys.
Uniaxial compression of Ti, B, and T-B powders: Structurization in case of spherical Ti particles
Plasma-arc growth of refractory single crystals from SHS products and green mixtures: an autoreview
Synthesis of Composite Material in Al–Ti–B System during Combustion of Titanium and Boron Powders and Aluminum-Clad Granules of VT6 Alloy
Improved conductivity of aluminum-doped ZnO : the effect of hydrogen diffusion from a hydrogenated amorphous silicon capping layer
Plasma-deposited aluminum-doped ZnO (ZnO:Al) demonstrated a resistivity gradient as function of the film thickness, extending up to about 600¿nm. This gradient decreased sharply when the ZnO:Al was capped by a hydrogenated amorphous silicon layer (a-Si:H) and subsequently treated according to the solid phase crystallization (SPC) procedure at 600¿°C. The resistivity reduced from 1.2¿·¿10-1 to 2.6¿·¿10-3 O¿·¿cm for a film thickness of 130¿nm, while for thicker films the decrease in resistivity was less pronounced, i.e., a factor of 2 for a film thickness of 810¿nm. While the carrier concentration was not affected, the mobility significantly increased from 7 to 30 cm2/V¿·¿s for the thick ZnO:Al layers. This increase was ascribed to the passivation of grain boundary defects by hydrogen, which diffused from the a-Si:H toward the ZnO:Al during the SPC procedure. The passivation effect was more pronounced in thinner ZnO:Al layers, characterized by a smaller grain size, due to the presence of large grain boundaries. For thicker films with grain sizes up to 200–300¿nm the mobility became progressively less affected by the presence of grain boundaries. Therefore, the hydrogen-induced improvement in conductivity was less significant for the thick ZnO:Al film
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