1,305 research outputs found
On the Benign One-Pot Preparation of Nanoporous Copper Thin Films with Bimodal Chan-nel Size Distributions by Chemical Dealloying in an Alkaline Solution
Nanoporous copper (NPC) thin films with bimodal channel size distributions can be benignly fabricated by one-pot chemical dealloying of dual-phase Al 27 at Cu alloy with hypereutectic structure in the NaOH solution. The microstructure of these NPC thin films was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis. The results show that these NPC thin films are composed of interconnected large-sized channels (100s of nm) with highly porous channel walls (10s of nm), in which large-sized channels resulting from entire dissolution of solid solution while small-sized those de-riving from part corrosion of intermetallics. Both large- and small-sized channels are 3D, open, and bicon-tinuous.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520
Entropy of the Schwarzschild-de Sitter Black Hole due to arbitrary spin fields in different Coordinates
By using the Newman-Penrose formalism and the improved thin-layer ``brick
wall'' approach, the statistical-mechanical entropies of the Schwarzschild-de
Sitter black hole arising from quantum massless arbitrary spin fields are
studied in the Painlev\'e and Lemaitre coordinates. Although the metrics in
both the Painlev\'e and the Lemaitre coordinates do not obviously possess the
singularities as that in the Schwarzschild-like coordinate, we find that, for
arbitrary spin fields, the entropies in the Painlev\'e and Lemaitre coordinates
are exactly equivalent to that in the Schwarzschild-like coordinate.Comment: 14 pages, no figure, to be published in JHE
A characterization of Schauder frames which are near-Schauder bases
A basic problem of interest in connection with the study of Schauder frames
in Banach spaces is that of characterizing those Schauder frames which can
essentially be regarded as Schauder bases. In this paper, we give a solution to
this problem using the notion of the minimal-associated sequence spaces and the
minimal-associated reconstruction operators for Schauder frames. We prove that
a Schauder frame is a near-Schauder basis if and only if the kernel of the
minimal-associated reconstruction operator contains no copy of . In
particular, a Schauder frame of a Banach space with no copy of is a
near-Schauder basis if and only if the minimal-associated sequence space
contains no copy of . In these cases, the minimal-associated
reconstruction operator has a finite dimensional kernel and the dimension of
the kernel is exactly the excess of the near-Schauder basis. Using these
results, we make related applications on Besselian frames and near-Riesz bases.Comment: 12 page
Entropy of entangled three-level atoms interacting with entangled cavity fields: entanglement swapping
The dynamics of an entangled atomic system in a partial interaction with
entangled cavity fields, characterizing an entanglement swapping, have been
studied through the use of Von Neuman entropy. We consider the interaction via
two-photon process given by a full microscopical Hamiltonian approach. The
explicit expression of the entropy is obtained, wherewith we estimated the
largest period. The numerical simulation of the entropy of the entangled atomic
and cavity systems shows that its time evolution presents multi-periodicity.
The effects of detuning parameter on the period and the amplitude of the
entropy are also discussed.Comment: 5 pages, 8 figure
Morphology and Orientation Selection of Non-Metallic Inclusions in Electrified Molten Metal
The effect of electric current on morphology and orientation selection of non-metallic inclusions in molten metal has been investigated using theoretical modelling and numerical calculation. Two geometric factors, namely the circularity (fc) and alignment ratio (fe) were introduced to describe the inclusions shape and configuration. Electric current free energy was calculated and the values were used to determine the thermodynamic preference between different microstructures. Electric current promotes the development of inclusion along the current direction by either expatiating directional growth or enhancing directional agglomeration. Reconfiguration of the inclusions to reduce the system electric resistance drives the phenomena. The morphology and orientation selection follows the routine to reduce electric free energy. The numerical results are in agreement with our experimental observations
Creep Lifetime Assessment of Pressure-Tight PE100 Pipes Based on a Slow Fatigue Crack Growth
Polyethylene pipes are widely used in water supply, gas, and sewage systems due to their excellent mechanical properties. A slow crack growth is the primary fracture mechanism for the pipes under long-term internal pressures. If the creep loading is treated as a special case of fatigue loading, the slow crack growth kinetics of polyethylene is defined in fatigue fracture tests at different stress ratios and extrapolated to creep crack kinetics. Linear elastic fracture mechanics concepts became the basis for predicting the creep lifetime of pressure-tight pipes subjected to various hoop stresses from extrapolated (synthetic) creep crack growth curves, and the prediction is in good agreement with the standard extrapolation, in accordance with ISO 9080.Полиэтиленовые трубы широко применяются в водоснабжении, системах газоснабжения и канализации благодаря их высоким механическим свойствам. Медленный рост трещин является основным механизмом разрушения полиэтиленовых труб под длительным внутренним давлением. Рассматривая нагружение при ползучести как особый случай усталостного нагружения, кинетика медленного роста трещин в полиэтиленовом материале определяется путем испытаний на усталостное разрушение при различных коэффициентах асимметрии цикла напряжений и экстраполируется на кинетику трещин ползучести. Исходя из теории линейноупругой механики разрушения долговечность при ползучести полиэтиленовой трубы под давлением, подверженной действию различных окружных напряжений, прогнозируется на основе синтетической кривой роста трещин ползучести, и прогнозы хорошо согласуются со стандартной экстрополяцией в соответствии с ISO 9080
Effects of low environmental salinity on the cellular profiles and expression of Na+, K+-ATPase and Na+, K+, 2Cl(-) cotransporter 1 of branchial mitochondrion-rich cells in the juvenile marine fish Monodactylus argenteus
The goal of this study was to determine the osmoregulatory ability of a juvenile marine fish, silver moony (), for the purpose of developing a new experimental species for ecophysiological research. In this study, was acclimated to freshwater (FW), brackish water (BW), or seawater (SW). The salinity tolerance of this euryhaline species was effective, and the fish survived well upon osmotic challenges. The largest apical surface of mitochondrion-rich cells was found in the FW individuals. Immunohistochemical staining revealed that Na+, K+-ATPase immunoreactive (NKA-IR) cells were distributed in the interlamellar region of the gill filaments of the silver moony in all experimental groups. In addition to the filaments, NKA-IR cells were also found in the lamellae of the FW individuals. The number of NKA-IR cells in the gills of the FW individuals exceeded that of the BW and SW individuals. The NKA-IR cells of FW and SW individuals exhibited bigger size than that of BW fish. The NKA activities and protein expression of the NKA alpha-subunit in the gills of the FW individuals were significantly higher than in the BW and SW groups. Additionally, the relative amounts of Na+, K+, 2Cl(-) cotransporter 1 (NKCC1) were salinity-dependent in the gills. Immunofluorescent signals of NKCC1 were localized to the basolateral membrane of NKA-IR cells in all groups. In the gills of the FW individuals, however, some NKA-IR cells did not exhibit a basolateral NKCC1 signal. In conclusion, the present study illustrated the osmoregulatory mechanisms of this easy- and economic-to-rear marine teleost with euryhaline capacity and proved the silver moony to be a good experimental animal
Solitons of two-component Bose-Einstein condensates modulated in space and time
In this paper we present soliton solutions of two coupled nonlinear
Schodinger equations modulated in the bspace and time. The approach allows us
to obatin solitons with large variety of solutions depending on the
nonlinearity and the potential profiles. As examples we show three cases with
soliton solution in such system, one of them with potential varying between
repulsive and attractive behavior and the others with nonlinearity localized
and delocalized, respectively.Comment: 18 pages, 8 figure
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