284 research outputs found
Особенности и последствия импортозамещения в России
The article discusses the features of the import substitution policy and reveals both positive and negative effects on food self-sufficiency of the population of Russia in the sanctions period. The study identified the direct effect of economic sanctions and imposed embargoes (loss of income, rise in prices for food products, reduction in the food basket), as well as the attitude of the population to the policy of food import substitution. The results of the sociological survey in the form of a volunteer survey of the population on the example of a particular region by the method of handout questionnaire are presented. It is concluded that a reorientation to the consumption of domestic food items occurred in the region while reducing the consumption of certain food items.El artículo analiza las características de la política de sustitución de importaciones e identifica consecuencias positivas y negativas para la autosuficiencia alimentaria de la población Rusa durante el período de las sanciones. El estudio reveló el impacto directo de las sanciones económicas y los embargos (pérdida de ingresos, aumento de los precios de los alimentos, reducción de la canasta de alimentos), así como las actitudes públicas hacia la política de sustitución de importaciones de alimentos. Presenta los resultados de una encuesta sociológica en forma de una encuesta voluntaria a la población sobre el ejemplo de una región específica por el método de distribución de cuestionarios. Se concluye que la región se ha desplazado al consumo de alimentos domésticos al tiempo que reduce el consumo de ciertos alimentos.В статье рассматриваются особенности политики импортозамещения и выявляются как положительные, так и отрицательные последствия для продовольственной самообеспеченности населения России в период санкций. В исследовании было выявлено прямое влияние экономических санкций и введенных эмбарго (потеря доходов, рост цен на продукты питания, сокращение продовольственной корзины), а также отношение населения к политике импортозамещения продовольствия. Представлены результаты социологического опроса в виде волонтерского опроса населения на примере конкретного региона методом раздаточного анкетирования. Сделан вывод о том, что в регионе произошла переориентация на потребление внутренних продуктов питания при одновременном сокращении потребления определенных продуктов питания
Dynamical spin-electric coupling in a quantum dot
Due to the spin-orbital coupling in a semiconductor quantum dot, a freely
precessing electron spin produces a time-dependent charge density. This creates
a sizeable electric field outside the dot, leading to promising applications in
spintronics. The spin-electric coupling can be employed for non-invasive single
spin detection by electrical methods. We also consider a spin relaxation
mechanism due to long-range coupling to electrons in gates and elsewhere in the
system, and find a contribution comparable to, and in some cases dominant over
previously discussed mechanisms.Comment: 4 pages, 2 figure
Observation of Caustics in the Trajectories of Cold Atoms in a Linear Magnetic Potential
We have studied the spatial and temporal dynamics of a cold atom cloud in the
conservative force field of a ferromagnetic guide, after laser cooling has been
switched off suddenly. We observe outgoing 'waves' that correspond to caustics
of individual trajectories of trapped atoms. This provides detailed information
on the magnetic field, the energy distribution and the spin states.Comment: 21 pages, incl. 12 figure
The brachistochrone problem in open quantum systems
Recently, the quantum brachistochrone problem is discussed in the literature
by using non-Hermitian Hamilton operators of different type. Here, it is
demonstrated that the passage time is tunable in realistic open quantum systems
due to the biorthogonality of the eigenfunctions of the non-Hermitian Hamilton
operator. As an example, the numerical results obtained by Bulgakov et al. for
the transmission through microwave cavities of different shape are analyzed
from the point of view of the brachistochrone problem. The passage time is
shortened in the crossover from the weak-coupling to the strong-coupling regime
where the resonance states overlap and many branch points (exceptional points)
in the complex plane exist. The effect can {\it not} be described in the
framework of standard quantum mechanics with Hermitian Hamilton operator and
consideration of matrix poles.Comment: 18 page
First-principles study of structural, electronic and thermodynamic properties of (ZnO)(n=2-16) clusters
The structural, electronic, and vibrational thermodynamic properties of the
(ZnO) (n=2-16) clusters are studied using density functional - full
potential computations. The results show, small clusters up to stabilize
in the 2D ring shape geometries while the larger clusters prefer the 3D cage
like structures. The ring to cage structural cross over in ZnO clusters is
studied by investigating the behavior of the Zn-O-Zn bond angle, the Zn-O bond
strength, and the number of bonds in the systems. It is argued that 12 is the
lowest magic number of ZnO clusters at ground state, while finite temperature
vibrational excitations enhance the relative stability of the (ZnO) cluster
and make it a magic system at temperatures above about 170 K. The obtained
electronic structure of ZnO clusters before and after applying the many-body GW
corrections evidence a size induced red shift originated from the ring to cage
structural cross over in these systems. The behavior of the extremal points of
electron density of the clusters along with the extrapolated cluster binding
energies at very large sizes may be evidences for existence of a metastable
structure for large ZnO nanostructures, different with the bulk ZnO structure.Comment: 8 pages, 8 figures and 1 tabl
Разработка методики количественного анализа целевого и побочных продуктов синтеза 1,3-бис(3,4-дицианофенокси)бензола методом ВЭЖХ
Objectives. Determination of target products and byproducts is necessary for the quality control of phthalonitrile monomer synthesis as well as production scaling and performing related kinetic studies. High-performance liquid chromatography (HPLC) is a simple and affordable method for quantitative chemical analysis, which also verifies the quality of raw materials. The objective of this study was to develop an HPLC technique for determining the composition of the reaction mixture in the synthesis of 1,3-bis(3,4-dicyanophenoxy)benzene (DPB).Methods. Reversed-phase HPLC was used to quantitatively analyze the reaction mixture.Results. A simple and rapid method for the quantitative HPLC analysis of phthalonitrile monomers and their mixtures with reagents was developed. Reaction times and the accumulation of byproducts were also studied.Conclusions. The successful performance of the developed technique allows us to recommend it for practical applications. The results obtained for reactors of different sizes have good convergence, and DPB synthesis was successfully scaled up to intermediate scale equipment.Цели. Для аналитического контроля производства фталонитрильных мономеров, изучения масштабирования технологии их получения и проведения кинетических исследований актуальна задача по разработке способа определения концентрации целевого и побочных продуктов в присутствии реагентов. Наиболее простым и доступным методом количественного анализа рассматриваемых соединений является высокоэффективная жидкостная хроматография (ВЭЖХ), позволяющая также проводить верификацию сырья и контроль качества готовой продукции. Цель данной работы заключалась в разработке методики количественного анализа компонентов реакционной смеси при синтезе 1,3-бис(3,4-дицианофенокси)бензола (ДБФ) методом ВЭЖХ.Методы. Для количественного анализа компонентов реакционной смеси использовали метод ВЭЖХ в обращенно-фазовом режиме.Результаты. Разработана простая и быстрая методика количественного анализа фталонитрильных мономеров и их смесей с реагентами методом ВЭЖХ. По данным исследования конверсии компонентов реакционной смеси сделан вывод о продолжительности реакции и накоплении побочных продуктов.Выводы. Успешная апробация позволяет рекомендовать разработанную методику для применения в аналитической практике. Результаты, полученные при переходе от реакции в колбе к реактору объемом 15 л, характеризуются хорошей сходимостью. Синтез ДФБ успешно масштабируется на оборудование промежуточного масштаба
Bound states in the continuum in open Aharonov-Bohm rings
Using formalism of effective Hamiltonian we consider bound states in
continuum (BIC). They are those eigen states of non-hermitian effective
Hamiltonian which have real eigen values. It is shown that BICs are orthogonal
to open channels of the leads, i.e. disconnected from the continuum. As a
result BICs can be superposed to transport solution with arbitrary coefficient
and exist in propagation band. The one-dimensional Aharonov-Bohm rings that are
opened by attaching single-channel leads to them allow exact consideration of
BICs. BICs occur at discrete values of energy and magnetic flux however it's
realization strongly depend on a way to the BIC's point.Comment: 5 pgaes, 4 figure
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