594 research outputs found
Observation of acoustic turbulence in a system of nonlinear second sound waves in superfluid 4He.
We discuss the results of recent studies of acoustic turbulence in a system of nonlinear second sound waves in a high-quality resonator filled with superfluid 4He. It was found that, when the driving amplitude was sufficiently increased, a steady-state direct wave cascade is formed involving a flux of energy towards high frequencies. The wave amplitude distribution follows a power law over a wide range of frequencies. Development of a decay instability at high driving amplitudes results in the formation of subharmonics of the driving frequency, and to a backflow of energy towards the low-frequency spectral domain, in addition to the direct cascade
Modeling of Isotropic Backward-Wave Materials Composed of Resonant Spheres
A possibility to realize isotropic artificial backward-wave materials is
theoretically analyzed. An improved mixing rule for the effective permittivity
of a composite material consisting of two sets of resonant dielectric spheres
in a homogeneous background is presented. The equations are validated using the
Mie theory and numerical simulations. The effect of a statistical distribution
of sphere sizes on the increasing of losses in the operating frequency band is
discussed and some examples are shown.Comment: 15 pages, 7 figure
Addressable graphene encapsulation of wet specimens on a chip for optical, electron, infrared and X-ray based spectromicroscopy studies
Label-free spectromicroscopy methods offer the capability to examine complex cellular phenomena. Electron and X-ray based spectromicroscopy methods, though powerful, have been hard to implement with hydrated objects due to the vacuum incompatibility of the samples and due to the parasitic signals from (or drastic attenuation by) the liquid matrix surrounding the biological object of interest. Similarly, for many techniques that operate at ambient pressure, such as Fourier transform infrared spectromicroscopy (FTIRM), the aqueous environment imposes severe limitations due to the strong absorption of liquid water in the infrared regime. Here we propose a microfabricated multi-compartmental and reusable hydrated sample platform suitable for use with several analytical techniques, which employs the conformal encapsulation of biological specimens by a few layers of atomically thin graphene. Such an electron, X-ray, and infrared transparent, molecularly impermeable and mechanically robust enclosure preserves the hydrated environment around the object for a sufficient time to allow in situ examination of hydrated bio-objects with techniques operating under both ambient and high vacuum conditions. An additional hydration source, provided by hydrogel pads lithographically patterned in the liquid state near/around the specimen and co-encapsulated, has been added to further extend the hydration lifetime. Note that the in-liquid lithographic electron beam-induced gelation procedure allows for addressable capture and immobilization of the biological cells from the solution. Scanning electron microscopy and optical fluorescence microscopy, as well as synchrotron radiation based FTIR and X-ray fluorescence microscopy, have been used to test the applicability of the platform and for its validation with yeast, A549 human carcinoma lung cells and micropatterned gels as biological object phantoms
USE OF ACOUSTICALLY VISCOUS SURFACES FOR NOISE DECREASE IN URBAN ENVIRONMENT
Π‘Π±ΠΎΡΠ½ΠΈΠΊ Π²ΡΠΏΡΡΠ΅Π½ ΠΏΡΠΈ ΠΏΠΎΠ΄Π΄Π΅ΡΠΆΠΊΠ΅ Π€ΠΎΠ½Π΄Π° ΡΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΡ ΡΠ°Π·Π²ΠΈΡΠΈΡ Π£ΡΠ€Π£ ΠΈΠΌΠ΅Π½ΠΈ ΠΏΠ΅ΡΠ²ΠΎΠ³ΠΎ ΠΡΠ΅Π·ΠΈΠ΄Π΅Π½ΡΠ° Π ΠΎΡΡΠΈΠΈ Π.Π. ΠΠ»ΡΡΠΈΠ½
Matter and physical anisotropy of ultramafites of the Barkhatny massif (Kuznetsk Alatau ridge, Western Siberia) as criteria of their mineral potential for geological prospecting works
A complex of petrographic, petrofabric, and paleomagnetic analyses that was carried out for rocks from an ultrabasic massif of the Barkhatnaya Mountain in the Northern part of the Kuznetsk Alatau allowed us to prove that internal anisotropy of mineral aggregates had deformation-type evolution, which indicates possible plastic exhumation of lithosphere mantle fragments into upper crust levels. Complete conformity of geophysical and petrofabric parameters points out high possibility of multistage model for obduction of ophiolite association segments proposed for this region. Taking into account specifics of minerageny for such complexes (chromite ores and noble metals, asbestos and nephrites), we offer a new technology for geological prospecting works at the stage of estimating mineral potential of such geological objects, which is based on the presence of differently oriented systems of mineral plane orientation.ΠΡΠΎΠ²Π΅Π΄Π΅Π½Π½ΡΠΉ Π½Π°ΠΌΠΈ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡ ΡΡΡΡΠΊΡΡΡΠ½ΠΎ-ΠΏΠ΅ΡΡΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈ ΠΏΠ°Π»Π΅ΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΡΡ
ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ Π΄Π»Ρ ΡΠ»ΡΡΡΠ°Π±Π°Π·ΠΈΡΠΎΠ² ΠΠ°ΡΡ
Π°ΡΠ½ΠΎ- Π³ΠΎ ΠΌΠ°ΡΡΠΈΠ²Π° Π½Π° ΡΠ΅Π²Π΅ΡΠ½ΠΎΠΌ ΡΠΊΠ»ΠΎΠ½Π΅ ΠΡΠ·Π½Π΅ΡΠΊΠΎΠ³ΠΎ ΠΠ»Π°ΡΠ°Ρ ΠΏΠΎΠ΄ΡΠ²Π΅ΡΠΆΠ΄Π°Π΅Ρ, ΡΡΠΎ Π²Π½ΡΡΡΠ΅Π½Π½ΡΡ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΡ ΠΌΠΈΠ½Π΅ΡΠ°Π»ΡΠ½ΡΡ
Π°Π³ΡΠ΅Π³Π°ΡΠΎΠ² ΠΈΠΌΠ΅- Π»Π° Π΄Π΅ΡΠΎΡΠΌΠ°ΡΠΈΠΎΠ½Π½ΡΡ ΡΠ²ΠΎΠ»ΡΡΠΈΡ, ΠΊΠΎΡΠΎΡΠ°Ρ ΡΠΊΠ°Π·ΡΠ²Π°Π΅Ρ Π½Π° Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΡΡ ΠΏΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΡΡ ΡΠΊΡΠ³ΡΠΌΠ°ΡΠΈΡ ΡΡΠ°Π³ΠΌΠ΅Π½ΡΠΎΠ² ΠΌΠ°Π½ΡΠΈΠΈ Π»ΠΈΡΠΎΡΡΠ΅ΡΡ Π² Π²Π΅ΡΡ
Π½ΠΈΠ΅ Π³ΠΎΡΠΈΠ·ΠΎΠ½ΡΡ Π·Π΅ΠΌΠ½ΠΎΠΉ ΠΊΠΎΡΡ. ΠΠΎΠ»Π½ΠΎΠ΅ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΠΈΠ΅ Π³Π΅ΠΎΡΠΈΠ·ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΈ ΠΏΠ΅ΡΡΠΎΡΡΡΡΠΊΡΡΡΠ½ΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΠΎΡΠΌΠ΅ΡΠ°Π΅Ρ Π²ΡΡΠΎΠΊΡΡ Π²Π΅ΡΠΎΡΡΠ½ΠΎΡΡΡ ΠΌΠ½ΠΎΠ³ΠΎΡΡΠ°Π΄ΠΈΠΉΠ½ΠΎΠΉ ΠΎΠ±Π΄ΡΠΊΡΠΈΠΈ ΡΡΠ°Π³ΠΌΠ΅Π½ΡΠΎΠ² ΠΎΡΠΈΠΎΠ»ΠΈΡΠΎΠ²ΠΎΠΉ Π°ΡΡΠΎΡΠΈΠ°ΡΠΈΠΈ, ΠΏΡΠ΅Π΄Π»Π°Π³Π°Π΅ΠΌΠΎΠΉ Π΄Π»Ρ ΡΡΠΎΠ³ΠΎ ΡΠ΅Π³ΠΈΠΎΠ½Π°. ΠΡΠΈΠ½ΠΈΠΌΠ°Ρ Π²ΠΎ Π²Π½ΠΈΠΌΠ°Π½ΠΈΠ΅ ΠΎΡΠΎΠ±Π΅Π½Π½ΠΎΡΡΠΈ ΠΌΠΈΠ½Π΅ΡΠ°Π³Π΅Π½ΠΈΠΈ (Ρ
ΡΠΎΠΌΠΈΡΠΎΠ²ΡΠ΅ ΡΡΠ΄Ρ ΠΈ Π±Π»Π°Π³ΠΎΡΠΎΠ΄Π½ΡΠ΅ ΠΌΠ΅ΡΠ°Π»Π»Ρ, Π°ΡΠ±Π΅ΡΡ ΠΈ Π½Π΅ΡΡΠΈΡ) Π΄Π»Ρ ΡΠ°ΠΊΠΈΡ
ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠΎΠ² ΠΌΡ ΠΏΡΠ΅Π΄Π»Π°Π³Π°Π΅ΠΌ Π½ΠΎΠ²ΡΠ΅ ΠΌΠ΅ΡΠΎΠ΄Ρ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΎΡΠ°Π·Π²Π΅Π΄ΠΎΡΠ½ΡΡ
ΡΠ°Π±ΠΎΡ Π½Π° ΡΡΠ°Π΄ΠΈΠΈ ΠΎΡΠ΅Π½ΠΊΠΈ ΡΡΠ΄ΠΎΠ½ΠΎΡΠ½ΠΎΡΡΠΈ Π³Π΅ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΎΠ±ΡΠ΅ΠΊΡΠΎΠ², ΠΊΠΎΡΠΎΡΡΠ΅ Ρ
Π°ΡΠ°ΠΊ- ΡΠ΅ΡΠΈΠ·ΡΡΡΡΡ Π΄ΠΈΡΠΊΡΠ΅ΡΠ½ΡΠΌΠΈ Π²Π°ΡΠΈΠ°ΡΠΈΡΠΌΠΈ ΠΏΡΠΎΡΡΡΠ°Π½ΡΡΠ²Π΅Π½Π½ΠΎΠΉ ΠΎΡΠΈΠ΅Π½ΡΠΈΡΠΎΠ²ΠΊΠΈ ΡΠ»Π΅ΠΌΠ΅Π½ΡΠΎΠ² ΡΠ΅ΠΊΡΡΡΡΠ½ΠΎΠΉ Π°Π½ΠΈΠ·ΠΎΡΡΠΎΠΏΠΈΠΈ ΠΏΠΎΡΠΎΠ΄
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