53 research outputs found
Pulsed Laser Deposition of Large‐Area Thin Films and Coatings
Simple and inexpensive methods of obtaining large‐area uniform in thickness and composition thin films on rotating substrates and moving ribbons through pulsed laser deposition have been proposed. Thin films of different compositions were prepared using these methods. The thickness uniformity of obtained films was preserved within the limits of ±3% on up to 300 mm diameter substrates. Also, a method of creating a laser spot with a certain configuration on the target is proposed allowing almost full utilization of the target material
Current-biased Transition-edge Sensors Based on Re-entrant Superconductors
AbstractTransition-edge sensors are widely recognized as one of the most sensitive tools for the photon and particles detection in many areas, from astrophysics to quantum computing. Their application became practical after understanding that rather than being biased in a constant current mode, they should be biased in a constant voltage mode. Despite the methods of voltage biasing of these sensors are well developed since then, generally the current biasing is more convenient for superconducting circuits. Thus transition-edge sensors designed inherently to operate in the current-biased mode are desirable. We developed a design for such detectors based on re-entrant superconductivity. In this case constant current biasing takes place in the normal state, below the superconducting transition, so that following the absorption of a photon it does not yield a latching. Rather, the sensor gains energy and shifts towards the lower resistant (e.g., superconducting) state, and then cools down faster (since Joule heating is now reduced), and resets in a natural way to be able to detect the next photon. We prototyped this kind of transition edge sensors and tested them operational in accordance with the outlined physics. The samples used in experiments were modified compositions of YBCO-superconductors in a ceramic form (which, as we discovered, reproducibly demonstrates re-entrant superconductivity). In this presentation we report their composition, methods of preparation, and the detection results. This approach, in some areas, may have practical advantage over the traditional voltage-biased devices
Current-biased Transition-edge Sensors Based on Re-entrant Superconductors
Transition-edge sensors are widely recognized as one of the most sensitive tools for the photon and particles detection in many areas, from astrophysics to quantum computing. Their application became practical after understanding that rather than being biased in a constant current mode, they should be biased in a constant voltage mode. Despite the methods of voltage biasing of these sensors are well developed since then, generally the current biasing is more convenient for superconducting circuits. Thus transition-edge sensors designed inherently to operate in the current-biased mode are desirable. We developed a design for such detectors based on re-entrant superconductivity. In this case constant current biasing takes place in the normal state, below the superconducting transition, so that following the absorption of a photon it does not yield a latching. Rather, the sensor gains energy and shifts towards the lower resistant (e.g., superconducting) state, and then cools down faster (since Joule heating is now reduced), and resets in a natural way to be able to detect the next photon. We prototyped this kind of transition edge sensors and tested them operational in accordance with the outlined physics. The samples used in experiments were modified compositions of YBCO-superconductors in a ceramic form (which, as we discovered, reproducibly demonstrates re-entrant superconductivity). In this presentation we report their composition, methods of preparation, and the detection results. This approach, in some areas, may have practical advantage over the traditional voltage-biased devices
Environmental aspects of post-operational bioremediation of the typical municipal solid waste landfill of the administrative district
The article deals with the environmental consequences o f testing the method o f biological remediation o f the closed typical municipal solid waste landfill of the administrative district. The essence o f the method consists in the introduction of adapted composites from aboriginal, adapted or modified biological systems, primarily microorganisms for catalysis o f the decomposition process o f the organic component of waste landfills and subsequent separation o f valuable recyclable materials. The article presents the results o f the impact assessment o f a typical solid municipal waste landfil
New dynamo pattern revealed by solar helical magnetic fields
Previously unobservable mirror asymmetry of the solar magnetic field -- a key
ingredient of the dynamo mechanism which is believed to drive the 11-year
activity cycle -- has now been measured. This was achieved through systematic
monitoring of solar active regions carried out for more than 20 years at
observatories in Mees, Huairou, and Mitaka. In this paper we report on detailed
analysis of vector magnetic field data, obtained at Huairou Solar Observing
Station in China. Electric current helicity (the product of current and
magnetic field component in the same direction) was estimated from the data and
a latitude-time plot of solar helicity during the last two solar cycles has
been produced. We find that like sunspots helicity patterns propagate
equatorwards but unlike sunspot polarity helicity in each solar hemisphere does
not change sign from cycle to cycle - confirming the theory. There are,
however, two significant time-latitudinal domains in each cycle when the sign
does briefly invert. Our findings shed new light on stellar and planetary
dynamos and has yet to be included in the theory.Comment: 4 pages, 2 figures 0 tables. MNRAS Letters, accepte
Kinematic dynamo wave in the vicinity of the solar poles
We consider a dynamo wave in the solar convective shell for the kinematic
-dynamo model. The spectrum and eigenfunctions of the
corresponding equations are derived analytically with the aid of the WKB
method. Our main aim here is to investigate the dynamo wave behavior in the
vicinity of the solar poles. Explicit expressions for the incident and
reflected waves are obtained. The reflected wave is shown to be relatively weak
in comparison to the incident wave. The phase shifts and the ratio of
amplitudes of the two waves are found.Comment: 20 pages, 2 EPS figure
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