Spatial and Wavenumber Resolution of Doppler Reflectometry

Doppler reflectometry spatial and wavenumber resolution is analyzed within the framework of the linear Born approximation in slab plasma model. Explicit expression for its signal backscattering spectrum is obtained in terms of wavenumber and frequency spectra of turbulence which is assumed to be radially statistically inhomogeneous. Scattering efficiency for both back and forward scattering (in radial direction) is introduced and shown to be inverse proportional to the square of radial wavenumber of the probing wave at the fluctuation location thus making the spatial resolution of diagnostics sensitive to density profile. It is shown that in case of forward scattering additional localization can be provided by the antenna diagram. It is demonstrated that in case of backscattering the spatial resolution can be better if the turbulence spectrum at high radial wavenumbers is suppressed. The improvement of Doppler reflectometry data localization by probing beam focusing onto the cut-off is proposed and described. The possibility of Doppler reflectometry data interpretation based on the obtained expressions is shown.Comment: http://stacks.iop.org/0741-3335/46/114

Cooling of Akmal-Pandharipande-Ravenhall neutron star models

We study the cooling of superfluid neutron stars whose cores consist of nucleon matter with the Akmal-Pandharipande-Ravenhall equation of state. This equation of state opens the powerful direct Urca process of neutrino emission in the interior of most massive neutron stars. Extending our previous studies (Gusakov et al. 2004a, Kaminker et al. 2005), we employ phenomenological density-dependent critical temperatures T_{cp}(\rho) of strong singlet-state proton pairing (with the maximum T_{cp}^{max} \sim 7e9 K in the outer stellar core) and T_{cnt}(\rho) of moderate triplet-state neutron pairing (with the maximum T_{cnt}^{max} \sim 6e8 K in the inner core). Choosing properly the position of T_{cnt}^{max} we can obtain a representative class of massive neutron stars whose cooling is intermediate between the cooling enhanced by the neutrino emission due to Cooper pairing of neutrons in the absence of the direct Urca process and the very fast cooling provided by the direct Urca process non-suppressed by superfluidity.Comment: 9 pages, 6 figures; accepted for publication in MNRA

Enhanced cooling of neutron stars via Cooper-pairing neutrino emission

We simulate cooling of superfluid neutron stars with nucleon cores where direct Urca process is forbidden. We adopt density dependent critical temperatures $T_{cp}(\rho)$ and $T_{cn}(\rho)$ of singlet-state proton and triplet-state neutron pairing in a stellar core and consider a strong proton pairing (with maximum T_{cp}^{max} \ga 5 \times 10^9 K) and a moderate neutron pairing ($T_{cn}^{max} \sim 6 \times 10^8$ K). When the internal stellar temperature $T$ falls below $T_{cn}^{max}$, the neutrino luminosity $L_{CP}$ due to Cooper pairing of neutrons behaves $\propto T^8$, just as that produced by modified Urca process (in a non-superfluid star) but is higher by about two orders of magnitude. In this case the Cooper-pairing neutrino emission acts like an enhanced cooling agent. By tuning the density dependence $T_{cn}(\rho)$ we can explain observations of cooling isolated neutron stars in the scenario in which direct Urca process or similar process in kaon/pion condensed or quark matter are absent.Comment: 9 pages, 3 figures, submitted to A&

Cooling of Neutron Stars: Two Types of Triplet Neutron Pairing

We consider cooling of neutron stars (NSs) with superfluid cores composed of neutrons, protons, and electrons (assuming singlet-state pairing of protons, and triplet-state pairing of neutrons). We mainly focus on (nonstandard) triplet-state pairing of neutrons with the $|m_J| = 2$ projection of the total angular momentum of Cooper pairs onto quantization axis. The specific feature of this pairing is that it leads to a power-law (nonexponential) reduction of the emissivity of the main neutrino processes by neutron superfluidity. For a wide range of neutron critical temperatures $T_{cn}$, the cooling of NSs with the $|m_J| = 2$ superfluidity is either the same as the cooling with the $m_J = 0$ superfluidity, considered in the majority of papers, or much faster. The cooling of NSs with density dependent critical temperatures $T_{cn}(\rho)$ and $T_{cp}(\rho)$ can be imitated by the cooling of the NSs with some effective critical temperatures $T_{cn}$ and $T_{cp}$ constant over NS cores. The hypothesis of strong neutron superfluidity with $|m_J| = 2$ is inconsistent with current observations of thermal emission from NSs, but the hypothesis of weak neutron superfluidity of any type does not contradict to observations.Comment: 10 pages, 6 figure

Spectral Properties of Single Crystals of Synthetic Diamond

The half-width of the spectrum of Raman scattering (RS) of the first order of a diamond single crystal grown in a nickel-free system containing nitrogen getters is identical to all growth sectors (1.69 ± 0.02 cm−1). The sectorial inhomogeneity is not reflected in the transmission spectra and birefringence of this crystal. The nitrogen concentration is 4⋅1017 cm−3. For different growth sectors of the diamond crystal grown in the Ni–Fe–C system, the half-width of the Raman line varies from 1.74 to 2.08 cm−1, differences in the transmission spectra and birefringence are observed, and photoluminescence is revealed. The concentration of nitrogen in the growth sectors {001} is 1.6⋅1019 cm−3, the content of nickel is estimated to be at a level of 1019 cm−3, and the content of nitrogen in the {111} sectors is 4⋅1019 cm−3

Белорусско-русское двуязычие - исторически сложившаяся духовно-культурная ценность народа

During rapid economic development and emergence of new technologies, as well as the expansion of intercultural communications, improving the knowledge of foreign languages is one of the conditions for a successful adaptation of new generations in the social space and for the mastery of global scientific, technical, spiritual and cultural competencies. According to the latest data, about 70% of the world population speaks more than one language, while the bilingual people communicate to the best of their education. Nevertheless, the bilingualism problem is not removed from the agenda and is quite relevant for Belarus, which requires further scientific study.В период бурного экономического развития и появления новых технологий, расширения межкультурных коммуникаций, одним из условий успешной адаптации новых поколений в социальном пространстве и овладения общемировыми научно-техническими и духовно-культурными компетенциями является совершенствование знаний иностранных языков. По последним данным, в мире около 70 % населения владеют более чем одним языком, при этом на двух языках люди общаются в меру своей образованности. Тем не менее, проблема билингвизма не снимается с повестки дня и является достаточно актуальной для Беларуси, что требует дальнейшей научной проработки

Symmetry of the Neutron and Proton Superfluidity Effects in Cooling Neutron Stars

We investigate the combined effect of neutron and proton superfluidities on the cooling of neutron stars whose cores consist of nucleons and electrons. We consider singlet-state pairing of protons and triplet-state pairing of neutrons in the cores of neutron stars. The critical superfluid temperatures T_c are assumed to depend on the density of matter. We study two types of neutron pairing with different components of the total angular momentum of Cooper pairs along the quantization axis (|m_J| =0 or 2). Our calculations are compared with observations of thermal emission from isolated neutron stars. We show that the observations can be interpreted by using two classes of superfluidity models: (1) strong proton superfluidity with a maximum critical temperature in the stellar core T_c^{max} > 4 \times 10^9 K and weak neutron superfluidity of any type (T_c^{max} < 2 \times 10^8 K); (2) strong neutron superfluidity (pairing with |m_J|=0) and weak proton superfluidity. The two types of models reflect an approximate symmetry with respect to an interchange of the critical temperatures of neutron and proton pairing.Comment: 20 pages, 8 figure

Приоритетные направления повышения эффективности, конкурентоспособности и устойчивости развития аграрной отрасли Республики Беларусь

Importance of agriculture as a central link of agro-industrial complex for ensuring the food security of the Republic of Belarus cannot be overestimated. However, low profitability of greater part of agricultural producers along with a complicated financial situation require development of ways to improve the efficiency, competitiveness and stability of the industry focusing on improving price, credit and tax policies for agricultural companies. It is also vital to intensify investment activities aimed at a wider use of innovations. When improving the management system, considerable attention should be paid to integrated formations. Due to implementation of quality management systems, it is possible to increase the quality and safety of agricultural products. The paper dwells on the main factors and conditions having effect on raising the efficiency and competitiveness of agricultural sector and stability of its development. Despite significant achievements and positive results in the AIC of Belarus, a number of engineering, economic and social problems remain. Solutions are proposed to solve some of them. In particular, attention is paid to further improvement of economic mechanism of management, the most important components of which are pricing, crediting, taxation and state support and investment for agriculture. All these, combined with proposals to improve the management system of the agrarian sector in conditions of ongoing transformational changes and along with solving problems in activities of integrated formations, as well as implementation of proposals to improve foreign economic activity in the agro-industrial sector, can ensure stable and efficient functioning of agrarian sector. The proposed priority trends can be used for improving the state agrarian policy measures.Значение сельского хозяйства как центрального звена агропромышленного комплекса в обеспечении продовольственной безопасности Республики Беларусь нельзя переоценить. Однако низкая рентабельность большинства аграрных товаропроизводителей в совокупности со сложным финансовым положением вызывают необходимость разработки направлений повышения эффективности, конкурентоспособности и устойчивости отрасли с акцентом на совершенствование ценовой, кредитной и налоговой политики в отношении сельскохозяйственных организаций. Также важно активизировать инвестиционную деятельность, направленную на более широкое использование инноваций. При совершенствовании системы управления необходимо значительное внимание уделить интегрированным формированиям. Благодаря внедрению систем менеджмента качества можно достичь повышения качества и безопасности продукции АПК. В статье рассмотрены основные факторы и условия, влияющие на повышение эффективности и конкурентоспособности аграрной отрасли, устойчивости ее развития. Несмотря на существенные достижения и положительные результаты в АПК Беларуси, продолжает сохраняться ряд проблем технологического, экономического и социального характера. Предлагаются пути решения некоторых из них. В частности, акцентируется внимание на необходимости дальнейшего совершенствования экономического механизма хозяйствования, важнейшими составляющими которого являются ценообразование, кредитование, налогообложение и государственная поддержка сельского хозяйства и его инвестирование. Это в сочетании с предложениями по совершенствованию системы управления аграрной отраслью в условиях происходящих трансформационных изменений и наряду с решением проблем в деятельности интегрированных формирований, а также реализацией предложений по совершенствованию внешнеэкономической деятельности в сфере АПК способно обеспечить стабильное и эффективное функционирование аграрной отрасли. Предложенные приоритетные направления могут быть использованы при совершенствовании мер государственной аграрной политики