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

Сборник выпущен при поддержке Фонда содействия развитию УрФУ имени первого Президента России Б.Н. Ельцин

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.Проведенный нами комплекс структурно-петрологических и палеомагнитных исследований для ультрабазитов Бархатно- го массива на северном склоне Кузнецкого Алатау подтверждает, что внутренняя анизотропия минеральных агрегатов име- ла деформационную эволюцию, которая указывает на возможную пластическую эксгумацию фрагментов мантии литосферы в верхние горизонты земной коры. Полное соответствие геофизических и петроструктурных параметров отмечает высокую вероятность многостадийной обдукции фрагментов офиолитовой ассоциации, предлагаемой для этого региона. Принимая во внимание особенности минерагении (хромитовые руды и благородные металлы, асбест и нефрит) для таких комплексов мы предлагаем новые методы геологоразведочных работ на стадии оценки рудоносности геологических объектов, которые харак- теризуются дискретными вариациями пространственной ориентировки элементов текстурной анизотропии пород