346 research outputs found
Clinical Case of Huge Congenital Hypertrophy of the Retinal Pigment Epithelium Labeled as Choroidal Melanoma
A case of a 48-year-old woman who was referred to an Ocular Oncology Unit with a suspected choroidal melanoma diagnosis in her left eye, which final diagnosis was a congenital hypertrophy of the retinal pigment epithelium (CHRPE). No evidence of other ocular or general condition findings has been reported. Diagnostic, as well as the risks of malignancy, are discussed. We highlight the importance of performing an appropriate differential diagnosis of a large pigmented lesion detected on routine ocular examination due to the implications for the patient
Critical fields for vortex expulsion from narrow superconducting strips
We calculate the critical magnetic fields for vortex expulsion for an
infinitely long superconducting strip, using the Ginzburg-Landau formalism. Two
critical fields can be defined associated with the disappearance of either the
energetic stability or metastability of vortices in the center of the strip for
decreasing magnetic fields. We compare the theoretical predictions for the
critical fields in the London formalism with ours and with recently published
experimental results. As expected, for narrow strips our results reproduce
better the experimental findings.Comment: 5 pages, 5 figure
Effect of long-term operation on energy band bending at the SnO2 microcrystals interfaces in thin tin dioxide films with various catalysts
This work presents the results of investigation of stability of energy band bending at the SnO2 microcrystals interfaces in thin films of tin dioxide with deposited Pt and Pd dispersed layers (Pt/Pd/SnO2:Sb) and with the additions of gold in the bulk and on the surface (Au/SnO2:Sb, Au) in long - term operation. Measurements of energy band bending were showed that the significantly variation of this value is observed in first month of the sensor using. Perhaps this phenomenon is caused by the surface reconstruction during operation of sensors and consequently by the increase of density of oxygen ions chemisorbed on the surface of tin dioxide
Geometry-induced reduction of the critical current in superconducting nanowires
Reduction of the critical current in narrow superconducting NbN lines with
sharp and rounded bends with respect to the critical current in straight lines
was studied at different temperatures. We compare our experimental results with
the reduction expected in the framework of the London model and the
Ginsburg-Landau model. We have experimentally found that the reduction is
significantly less than either model predicts. We also show that in our NbN
lines the bends mostly contribute to the reduction of the critical current at
temperatures well below the superconducting transition temperature
Operation of a superconducting nanowire quantum interference device with mesoscopic leads
A theory describing the operation of a superconducting nanowire quantum
interference device (NQUID) is presented. The device consists of a pair of
thin-film superconducting leads connected by a pair of topologically parallel
ultra-narrow superconducting wires. It exhibits intrinsic electrical
resistance, due to thermally-activated dissipative fluctuations of the
superconducting order parameter. Attention is given to the dependence of this
resistance on the strength of an externally applied magnetic field aligned
perpendicular to the leads, for lead dimensions such that there is essentially
complete and uniform penetration of the leads by the magnetic field. This
regime, in which at least one of the lead dimensions lies between the
superconducting coherence and penetration lengths, is referred to as the
mesoscopic regime. The magnetic field causes a pronounced oscillation of the
device resistance, with a period not dominated by the Aharonov-Bohm effect
through the area enclosed by the wires and the film edges but, rather, in terms
of the geometry of the leads, in contrast to the well-known Little-Parks
resistance of thin-walled superconducting cylinders. A theory, encompassing
this phenomenology, is developed through extensions, to the setting of parallel
superconducting wires, of the Ivanchenko-Zil'berman-Ambegaokar-Halperin theory
for the case of short wires and the Langer-Ambegaokar-McCumber-Halperin theory
for the case of longer wires. It is demonstrated that the NQUID acts as a probe
of spatial variations in the superconducting order parameter.Comment: 20 pages, 18 figure
Usage of gamification theory for increase motivation of employees
© 2015, Mediterranean Center of Social and Educational Research. All rights reserved. Games have amazing ability to hold people's attention for a long time, build relationship, win recognition and develop creativity. Games can be considered as a sample of motivation and job involvment, so now we are trying to apply these techniques into the labor process. In the following article gamification term is given and history of gamification theory is analyzed. Besides problems of application of gamification method in sector of national economy are examined. Also analysis of the possibilities of implementation this theory to the Russian reality is presented
Properties of silicon dioxide layers with embedded metal nanocrystals produced by oxidation of Si:Me mixture
A two-dimensional layers of metal (Me) nanocrystals embedded in SiO2 were produced by pulsed laser deposition of uniformly mixed Si:Me film followed by its furnace oxidation and rapid thermal annealing. The kinetics of the film oxidation and the structural properties of the prepared samples were investigated by Rutherford backscattering spectrometry, and transmission electron microscopy, respectively. The electrical properties of the selected SiO2:Me nanocomposite films were evaluated by measuring C-V and I-V characteristics on a metal-oxide-semiconductor stack. It is found that Me segregation induced by Si:Me mixture oxidation results in the formation of a high density of Me and silicide nanocrystals in thin film SiO2 matrix. Strong evidence of oxidation temperature as well as impurity type effect on the charge storage in crystalline Me-nanodot layer is demonstrated by the hysteresis behavior of the high-frequency C-V curves
Hydrogen sensors based on In2O3 thin films with bimetallic Pt/Pd catalysts on the surface and tin and dysprosium impuri-ties in the bulk
This paper presents the results of studying the characteristics of hydrogen sensors based on thin In2O3 films modified with tin and dysprosium with dispersed double Pt/Pd catalysts deposited on the surface. To control the content of Sn and Dy in the films, an original technology was developed, and ceramic targets were fabricated from powders of the In–Dy–O, Dy–Sn–O, and In–Dy–Sn–O systems synthesized by the sol–gel method. Films of complex composition were obtained by RF magnetron sputtering of the corresponding targets. Structural features of the obtained thin films were studied by Raman spectroscopy. It is shown that various combinations of tin and dysprosium concentrations, as well as the presence of Pt/Pd catalysts on the surface, have a significant effect on the defectiveness of the films and the density of oxygen adsorption centers. As a result, the resistance of sensors in pure air (R0), the activation energies of the temperature dependences of R0, the bending of the energy bands at the grain boundaries of the semiconductor, and the responses to the action of hydrogen in the concentration range of 20–25,000 ppm change. A unique feature of Pt/Pd/ In2O3: Sn (0.5 at%), Dy (4.95 at%) films is their high sensitivity at 20–100 ppm and the absence of signal saturation in the region of high hydrogen concentrations of 5000–25,000 ppm, allowing them to be used to detect H2 in a wide range of concentrations
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