582 research outputs found

    The two Josephson junction flux qubit with large tunneling amplitude

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    In this paper we discuss solid-state nanoelectronic realizations of Josephson flux qubits with large tunneling amplitude between the two macroscopic states. The latter can be controlled via the height and wells form of the potential barrier, which is determined by quantum-state engineering of the flux qubit circuit. The simplest circuit of the flux qubit is a superconducting loop interrupted by a Josephson nanoscale tunnel junction. The tunneling amplitude between two macroscopically different states can be essentially increased, by engineering of the qubit circuit, if tunnel junction is replaced by a ScS contact. However, only Josephson tunnel junctions are particularly suitable for large-scale integration circuits and quantum detectors with preset-day technology. To overcome this difficulty we consider here the flux qubit with high-level energy separation between "ground" and "excited" states, which consists of a superconducting loop with two low-capacitance Josephson tunnel junctions in series. We demonstrate that for real parameters of resonant superposition between the two macroscopic states the tunneling amplitude can reach values greater than 1K. Analytical results for the tunneling amplitude obtained within semiclassical approximation by instanton technique show good correlation with a numerical solution.Comment: 8 pages, 4 figure

    Degenerate Odd Poisson Bracket on Grassmann Variables

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    A linear degenerate odd Poisson bracket (antibracket) realized solely on Grassmann variables is presented. It is revealed that this bracket has at once three nilpotent Δ\Delta-like differential operators of the first, the second and the third orders with respect to the Grassmann derivatives. It is shown that these Δ\Delta-like operators together with the Grassmann-odd nilpotent Casimir function of this bracket form a finite-dimensional Lie superalgebra.Comment: 5 pages, LATEX. Corrections of misprints. The relation (23) is adde

    Purely twistorial string with canonical twistor field quantization

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    We introduce new purely twistorial scale-invariant action describing the composite bosonic D=4 Nambu-Goto string with target space parametrized by the pair of D=4 twistors. We show that by suitable gauge fixing of local scaling one gets the bilinear twistorial action and canonical quantization rules for the two-dimensional twistor-string fields. We consider the Poisson brackets of all constraints characterizing our model and we obtain four first class constraints describing two Virasoro constraints and two U(1)xU(1) Kac-Moody (KM) local phase transformations.Comment: v3: 6p.(extended version), in press in Physical Review

    Влияние научно-технического прогресса на организацию полиграфического производства

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    Проведено дослідження актуальних тенденцій впливу науково-технічного прогресу на організацію поліграфічного виробництва.The research is devoted to the actual scientific and technical progress influence over polygraphy organization.Проведено исследование актуальных тенденций влияния научно-технического прогресса на организацию полиграфического производства

    Hodge Duality Operation And Its Physical Applications On Supermanifolds

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    An appropriate definition of the Hodge duality \star operation on any arbitrary dimensional supermanifold has been a long-standing problem. We define a working rule for the Hodge duality \star operation on the (2+2)(2 + 2)-dimensional supermanifold parametrized by a couple of even (bosonic) spacetime variables xμ(μ=0,1)x^\mu (\mu = 0, 1) and a couple of Grassmannian (odd) variables θ\theta and θˉ\bar\theta of the Grassmann algebra. The Minkowski spacetime manifold, hidden in the supermanifold and parametrized by xμ(μ=0,1)x^\mu (\mu = 0, 1), is chosen to be a flat manifold on which a two (1+1)(1 + 1)-dimensional (2D) free Abelian gauge theory, taken as a prototype field theoretical model, is defined. We demonstrate the applications of the above definition (and its further generalization) for the discussion of the (anti-)co-BRST symmetries that exist for the field theoretical models of 2D- (and 4D) free Abelian gauge theories considered on the four (2+2)(2 + 2)- (and six (4+2)(4 + 2))-dimensional supermanifolds, respectively.Comment: LaTeX file, 25 pages, Journal-versio

    Variation of fatty acid composition in seed oil in the collection of induced oil flax (Linum humile Mill.) mutants

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    A wide variety of application fields for flax seeds requires for breeders to develop new varieties with different characteristics, corresponding to the intended final product. The method of experimental mutagenesis is one of the ways to solve this problem. This method allows mutant lines with an array of morphometric and biochemical traits to be created from a single species and within a relatively short period of time. The article demonstrates that treatment of Linum humile Mill. seeds of the cultivars Iceberg and Solnech-ny with the new chemical mutagens DG-2, DG-6, DG-7, DG-9 (derivatives of dimethyl sulfate (DMS)) as well as with the mutagens DMS and EMS resulted in the production of mutant lines and accessions with altered morphometric and biochemical parameters. Seeds of the initial cultivars were treated with 0.5 and 0.05 % aqueous solutions of the above mentioned substances and planted in the field to raise M1, M2, and M3 generations. Ultimately, 27 types of mutations were identified and subdivided into five groups by morphometric characteristics. The fatty acid composition of seed oil for the isolated mutant specimens was studied: the content of palmitic, stearic, oleic, linoleic (w6) and lino-lenic (w3) acids, as well as the w6/w3 ratio. The statistical analysis showed significant distinctions between the mutant lines in the biochemical composition of the oil. A strong negative correlation between the content of linoleic and linolenic acids was demonstrated, as well as a positive relationship of average strength between the content of stearic and oleic acids for the both varieties. The mutant accessions obtained can be used as donor material for conducting breeding work on flax in various directions

    Математичне моделювання електропідсилювача керма транспортного засобу з черв’ячною передачею

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    The complexity and variety of requirements imposed on modern cars have led to a variety of designs of steering amplifiers, which are based on various physical phenomena and patterns (mechanical, pneumatic, hydraulic, electrical, etc.). Despite the difference in design and operating principles, steering amplifiers of domestic and foreign production are based on a large number of complex components and parts, which reduces their reliability. In addition, due to the constant impact of amplifiers on the controlled wheels, the driver does not feel changes in the behavior of the car on the road when disturbing influences occur, which reduces traffic safety and can lead to an accident. Therefore, increasing the sensitivity of the steering wheel to adverse factors acting on the wheels of the car while driving is one of the important tasks of improving power steering system. Introduction of electric power steering systems for cargo and passenger vehicles with a load capacity of up to 20 tons. this is a very urgent problem. In contrast to power steering system, which is still used in the control systems of high-tonnage vehicles, electric power is much simpler in design, does not require much time and costs for operation and repair. Electric power steering system with worm drive, which has a gear ratio significantly higher than those used in passenger cars, is considered. For this purpose, the formula for calculating the active moment of resistance due to the angle of transverse inclination of the pin and the corresponding system of differential equations characterizing the electric power steering system with worm drive are derived. Based on this, a functional diagram of the electric power steering control system has been developed, which is unified for worm drive steering systems and can serve as a base for modeling the steering system of cargo and passenger vehicles.Перераховані переваги електропідси-лювача в порівнянні з гідропідсилювачем керма. Наведено можливі компонування електропідсилювача керма. Виведена формула для розрахунку активного моменту опору, обумовленого кутом поперечного нахилу шворня. Дана система диференціальних рівнянь, що характеризують електропідсилювач керма з черв’ячною передачею. Зображена функціональна схема електро-підсилювача керма

    Quantum superposition of three macroscopic states and superconducting qutrit detector

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    Superconducting quantum coherent circuits have opened up a novel area of fundamental low-temperature science since they could potentially be the element base for future quantum computers. Here we report a quasi-three-level coherent system, the so-called superconducting qutrit, which has some advantages over a two-level information cell (qubit), and is based on the qutrit readout circuit intended to measure individually the states of each qubit in a quantum computer. The designed and implemented radio-frequency superconducting qutrit detector (rf SQUTRID) with atomic-size ScS-type contact utilizes the coherent-state superposition in the three-well potential with energy splitting Delta E_01/k_B=1.5 K at the 30th quantized energy level with good isolation from the electromagnetic environment. The reason why large values of Delta E_01 (and thus using atomic-size Nb-Nb contact) are required is to ensure an adiabatic limit for the quantum dynamics of magnetic flux in the rf SQUTRID.Comment: 9 pages, 5 figures, in v.3: text extended, inset in figure 1 (the device design) adde

    Radiation chemistry provides nanoscopic insights into the role of intermediate phases in CeO<sub>2</sub> mesocrystal formation

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    The role of intermediate phases in CeO2 mesocrystal formation from aqueous Ce(III) solutions subjected to gamma-radiation was studied. Radiolytically formed hydroxyl radicals convert soluble Ce(III) into less soluble Ce(IV). Transmission electron microscopy (TEM) and X-ray diffraction studies of samples from different stages of the process allowed the identification of several stages in CeO2 mesocrystal evolution following the oxidation to Ce(IV): (1) formation of hydrated Ce(IV)-hydroxides, serving as intermediates in the liquid-to-solid phase transformation; (2) CeO2 primary particle growth inside the intermediate phase; (3) alignment of the primary particles into "pre-mesocrystals" and subsequently to mesocrystals, guided by confinement of the amorphous intermediate phase and accompanied by the formation of "mineral bridges". Further alignment of the obtained mesocrystals into supracrystals occurs upon slow drying, making it possible to form complex hierarchical architectures
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