This work is devoted to the development of nanosphere lithography (NSL) technology, which is a low-cost and efficient method to form nanostructures for nanoelectronics, as well as optoelectronic, ...plasmonic and photovoltaic applications. Creating a nanosphere mask by spin-coating is a promising, but not sufficiently studied method, requiring a large experimental base for different sizes of nanospheres. So, in this work, we investigated the influence of the technological parameters of NSL by spin-coating on the substrate coverage area by a monolayer of nanospheres with a diameter of 300 nm. It was found that the coverage area increases with decreasing spin speed and time, isopropyl and propylene glycol content, and with increasing the content of nanospheres in solution. Moreover, the process of controllably reducing the size of nanospheres in inductively coupled oxygen plasma was studied in detail. It was determined that increasing the oxygen flow rate from 9 to 15 sccm does not change the polystyrene etching rate, whereas changing the high-frequency power from 250 to 500 W increases the etching rate and allows us to control the decreasing diameter with high accuracy. Based on the experimental data, the optimal technological parameters of NSL were selected and the nanosphere mask on Si substrate was created with coverage area of 97.8% and process reproducibility of 98.6%. Subsequently reducing the nanosphere diameter lets us obtain nanoneedles of various sizes, which can be used in field emission cathodes. In this work, the reduction of nanosphere size, silicon etching, and removal of polystyrene residues occurred in unified continuous process of plasma etching without sample unloading to atmosphere.
The result of removing of heavy non-equal mass particles from the theory can be described, at low energy, by the effective action, which is a series in inverse-square powers of the mass. We propose a ...new efficient tool to calculate the leading terms of this series based on the Schwinger proper-time method. Unequal masses give rise to a large number of effective vertices describing the explicit flavor symmetry breaking effects with well-defined coupling constants. Our method is pertinent to the theory with explicit and spontaneous chiral symmetry breaking, chiral gauge theory, standard and beyond standard model effective field theory, the theory of critical phenomena, cosmology, etc.
We study a discrete Miura-type transformation between the hierarcies of non-Abelian semi-infinite Volterra (Kac–van Moerbeke) and Toda lattices with operator coefficients in terms of the inverse ...spectral problem for three-diagonal band operators, which appear in the Lax representation for such systems. This inverse problem method, which amounts to reconstruction of the operator from the moments of its Weyl operator-valued function, can be used in solving initial-boundary value problem for the systems of both these hierarchies. It is shown that the Miura transformation can be easily described in terms of these moments. Using this description we establish a bijection between the Volterra hierarchy and the Toda sub-hierarchy which can be characterized via Lax operators corresponding to its lattices.
Highly transparent YAG:Ce ceramics (transmission of 72–82% for 2-mm-thick samples in 550–900 nm wavelength range) were fabricated by solid-state reactive sintering using a mixture of Ce2xY2-2xO3 ...(x = 0.001, 0.01, 0.03, and 0.05) and Al2O3 nanopowders synthesized by laser ablation with an additional round of pre-calcining before compaction. The synthesized YAG:Ce ceramic materials showed intense luminescence with a maximum at 525–545 nm. The measured absolute light yields of the synthesized YAG:Ce ceramics were 18–21 photon/MeV for 1–5 at.% Ce and 5 photon/MeV for 0.1 at.% Ce. The energy resolutions of the fabricated thin ceramic samples (2 mm) under 662 keV gamma ray were measured to be 10–15%. The decay curves of scintillations consisted of two components with the decay times depending on the Ce3+ concentration. The sample doped with 5 at.% of Ce exhibited the main fast component with 26 ns decay time. The measured data was compared to that of YAG:Ce and well-known CsI:Tl single crystal scintillators. The influence of dopant concentration on the optical, luminescence and scintillation properties was discussed.
•Highly transparent YAG-Ce ceramics were synthesized.•The decay constant of 5%Ce-YAG ceramic is 26 ns.•The absolute light yield of 1%Ce-YAG ceramic is 20 ph/MeV.
In this work, we demonstrate the high efficiency of optical emission spectroscopy to estimate the etching profile of silicon structures in SF
/C
F
/O
plasma. The etching profile is evaluated as a ...ratio of the emission intensity of the oxygen line (778.1 nm) to the fluorine lines (685.8 nm and 703.9 nm). It was found that for the creation of directional structures with line sizes from 13 to 100 μm and aspect ratio from ≈ 0.15 to ≈ 5 the optimal intensities ratio is in the range of 2-6, and for structures from 400 to 4000 μm with aspect ratio from ≈ 0.03 to ≈ 0.37 it is in the range 1.5-2. Moreover, the influence of the process parameters on the etching rate of silicon, the etching rate of aluminum, the inclination angle of the profile wall of the etched window, the selectivity of silicon etching with respect to aluminum, and the influence on the overetching (Bowing effect) of the structure was investigated.
The bounds on the light quark masses are obtained by fitting the squares of pseudoscalar meson masses m π 2 and m K 2 to second order in 1 / N c expansion. The result is an algebraic cubic curve ...whose coefficients are the known Weinberg values for the quark mass ratios m u / m d and m s / m d . Additional restrictions arise when using the ratio m s / m u d = 27.23 ( 10 ) quoted by FLAG for lattice simulations with four quark flavors. This provides a tight constraint on the ratio m u / m d = 0.455 ( 8 ) . Published by the American Physical Society 2024
A number of issues related to the inspection of large containers with bulk materials and liquids by the dual energy method are considered. A mathematical model of the inspection system has been ...developed, linking the parameters of the source and the bremsstrahlung detector, the test object and the inspection quality parameters. An algorithm to estimate the effective atomic number of a local inclusion is proposed.
•X-ray inspection of large containers with bulk materials and liquids are considered.•Dual and multi-energy methods estimate effective atomic number of local inclusions.•The results of computational simulation for integrated and counting modes are shown.•Recommendations to select bremsstrahlung source and detector parameters are given.
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