Radiation-Induced "Zero-Resistance State" and the Photon Assisted Transport

We demonstrate that the radiation induced "zero-resistance state" observed in a two-dimensional electron gas is a result of the non-trivial structure of the density of states of the systems and the photon assisted transport. A toy model of a structureless quantum tunneling junction where the system has oscillatory density of states catches most of the important features of the experiments. We present a generalized Kubo-Greenwood conductivity formula for the photon assisted transport in a general system, and show essentially the same nature of the transport anomaly in a uniform system.Comment: 4 pages, 3 figures. Please send comment to [email protected]. This version added a paragraph to discuss the implication of negative conductanc

Mechanical Properties of the Assembly Welded Joint of the Oil Transportation Tank After a Long-Term Service

The paper provides results of studying a change in mechanical properties of the design elements metal and assembly welded joints of a vertical steel tank after a long-term service in oil transport facilities

Terahertz superlattice parametric oscillator

We report a GaAs/AlAs superlattice parametric oscillator. It was pumped by a microwave field (power few mW) and produced 3rd harmonic radiation (frequency near 300 GHz). The nonlinearity of the active superlattice was due to Bragg reflections of conduction electrons at the superlattice planes. A theory of the nonlinearity indicates that parametric oscillation should be possible up to frequencies above 10 THz. The active superlattice may be the object of further studies of predicted extraordinary nonlinearities for THz fields.Comment: 10 pages, 4 figure

Diphtheria rare localization in adults

Last 25 years in the country established sporadic diphtheria morbidity (less than 0.1 per 100 000 people). In this situation, the attention of medical specialists pre-hospital and hospital health care system is reduced, especially for diseases with a rare localization of pathological process. Mentioned circumstances contribute to delayed diagnosis and treatment of his patients, the major cause of complicated infection, often its unfavorable outcome and a factor of the epidemic of trouble for the infection. The authors present material evidence that the rare forms of diphtheria in the period of sporadic disease in much the same as in the epidemic, and describe the clinical manifestations and course of diphtheria of the nose, eyes, throat, genitals, mouth and gastrointestinal tract in modern conditions

Macro- and microelemental composition of the Antarctic fish blood serum

The research materials were selected during the 9-th Ukrainian Antarctic expedition in Academic Vernadsky station region. For analysis the fish samples that related to Nototheniidae, Bathydraconidae and Chaenichthyidae were used. The elemental composition of fish blood serum was estimated by flame atomic absorption spectroscopy and X-ray fluorescence spectroscopy. The elemental analysis of blood serum of the Antarctic fish revealed the species- dependent distribution. The expedience of the fish blood serum use for environmental biotesting is proposed

Ion Chambers for Monitoring the NuMI Neutrino Beam at FNAL

The Neutrinos at the Main Injector (NuMI) beamline will deliver an intense muon neutrino beam by focusing a beam of mesons into a long evacuated decay volume. The beam must be steered with 1 mRad angular accuracy toward the Soudan Underground Laboratory in northern Minnesota. We have built 4 arrays of ionization chambers to monitor the neutrino beam direction and quality. The arrays are located at 4 stations downstream of the decay volume, and measure the remnant hadron beam and tertiary muons produced along with neutrinos in meson decays. We review how the monitors will be used to make beam quality measurements, and as well we review chamber construction details, radiation damage testing, calibration, and test beam results.Comment: paper to appear in the proceedings of the 11th Beam Instrumentation Workshop, Oak Ridge, T