Scientists have determined the properties of unseen "tails" sticking out of supermassive black holes at the heart of active galactic nuclei by analyzing unexpected discrepancies between the data of high-precision observations conducted by an international network of radio telescopes and that of Gaia -- a space observatory of the European Space Agency carrying optical telescopes on board."It is no exaggeration to say that a new area of observational astrophysics has begun," says Yuri Kovalev who heads MIPT's Laboratory of Relativistic Astrophysics and a laboratory at the Lebedev Physical Institute (LPI) of the Russian Academy of Sciences."By comparing the data from radio interferometers and optical telescopes, we can obtain information about hot jets and the accretion disks surrounding black holes at the center of galaxies in the visible part of the spectrum.Yuri Kovalev and Leonid Petrov from MIPT and LPI collaborated on a research paper, which has recently been published in Monthly Notices of the Royal Astronomical Society, that analyzes the coordinates of active nuclei of remote galaxies obtained independently by very long baseline interferometry, or VLBI, and the Gaia space astrometry observatory.In 2013, the European space observatory Gaia was launched with an aim of cataloging the precise coordinates and velocities of 1 billion stars in our Galaxy.More than 10,000 of these are extremely bright active galactic nuclei called quasars.
A single-walled carbon nanotube, or SWNT, can be pictured as a graphene sheet rolled into a cylinder.Transparent and flexible carbon nanotube films -- that is, 2-D structures formed by intersecting nanotubes -- have a wide variety of potential applications, for example as supercapacitors or transparent electrodes in flexible electronics -- electronic devices that can be bent, folded, and twisted without breaking.The physicists measured optical and electrical properties of the films by terahertz-infrared spectroscopy at a variety of temperatures, from -268 degrees Celsius to room temperature, and in a wide range of incident radiation wavelengths -- from ultraviolet to terahertz (wavelengths of about 1 millimeter).On their surface, carbon monoxide (CO) disproportionation -- simultaneous oxidation and reduction -- occurs and finally SWNTs grow.By varying the duration of the collection time, one could obtain the films of different thicknesses.This method enables the production of high-quality nanotubes with no amorphous carbon impurities.
Lebedev Physical Institute of the Russian Academy of Sciences and Dagestan State University, have conducted an experiment with the help of muon radiography method (a modern method of scanning the internal structure of substances) that could turn out to be substantial.The research group non-invasively scanned the hidden space underground the northwestern part of the Naryn-Kala fortress (Derbent).The 12-meter section is almost completely hidden underground, and only a piece of a dilapidated dome is visible from the surface.The structure dates back to around the year 300 A.D. Until recently, people in the area believed this was just an underground reservoir.However, recent archeological research suggests this structure is the oldest Christian Temple in modern-day Russian.Not all archeologists agree with the last interpretation.
Shown in figure 1, a lamp of this kind relies on the same principle that powered the old TVs using cathode-ray tubes: A negatively charged electrode, or cathode, at one end of a vacuum tube serves as an electron gun.A potential difference of up to 10 kilovolts accelerates the emitted electrons toward a flat positively charged phosphor-coated electrode -- the anode -- at the opposite end of the tube.This electron bombardment results in light.Cathodoluminescent lamps have the advantage of being able to emit light almost at any wavelength, from the red to ultraviolet, depending on which fluorescent material is used.Novel ultraviolet light bulbs would be a particularly timely development, considering the recent ban on household appliances using mercury under the Minamata Convention, a United Nations treaty signed by 128 countries that came into effect in August 2017.Among other products, the ban targets ultraviolet fluorescent tubes, widely used for greenhouse lighting and other applications.
Lebedev Physical Institute of the Russian Academy of Sciences of the Russian Academy of Sciences, Skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State University and Dagestan State University have published the first results of a "scan" obtained by the method of muon radiography of the underground space in the Derbent fortress of Naryn-Kala.If this theory is confirmed, this building is one of the oldest churches in the world.The 12-meter building is almost completely hidden under the ground, only a fragment of a half-destroyed dome is visible above the surface.This building in the northwestern part of the Naryn-Kala fortress in Derbent dates back to about 300 A.D. To date, the issue of the function of the building has not been resolved: a reservoir, a Christian temple, or a Zoroastrian fire temple.It is not possible for archaeologists to come to a consensus because the excavations of the temple, used for two centuries as a reservoir, can destroy a UNESCO cultural heritage site.Therefore, to study the premises, scientists used the method of muon radiography, placing several innovative detectors with a nuclear emulsion inside a buried building at a depth of 10 meters from the surface of the earth.
(Samara Polytech (Samara State Technical University)) The research team that includes Samara Polytech scientists obtained monoclinic NaVPO4F by solid-state synthesis using quenching and showed that sodium ions were inactive.
More

Top