The effect of TT-invariance violation in scattering of polarized 3^3He nuclei on tensor-polarized deuterons

In the interaction of a transversely polarized nuclear beam with a tensor-polarized deuteron target, a nonzero value of the component of the total cross section of the process corresponding to this combination of polarizations is an unambiguous signal of $T$-invariance violation while $P$-parity is preserved. The method developed earlier for calculating this component of the total cross section for $pd$ scattering based on the Glauber theory has been generalized by us to the case of $^3$He$d$ scattering, and its energy dependence in the range of beam energies 0.1--1 GeV/nucleon has been calculated. It is found that in $^3$He$d$ collisions, in contrast to $pd$ scattering, the contribution of only one type of $T$-violating nucleon-nucleon forces dominates, which is essential for extraction of the unknown constant of this interaction from the corresponding data.Comment: 15 pages, 4 figures; accepted by JETP Letter

Theoretical Study of Spin Observables in pdpd Elastic Scattering at Energies Tp=800−1000T_p = 800-1000 MeV

Various spin observables (analyzing powers and spin-correlation parameters) in $pd$ elastic scattering at $T_p = 800-1000$ MeV are analyzed within the framework of the refined Glauber model. The theoretical model uses as input spin-dependent $NN$ amplitudes obtained from the most recent partial-wave analysis and also takes into account the deuteron $D$ wave and charge-exchange effects. Predictions of the refined Glauber model are compared with the existing experimental data. Reasonable agreement between the theoretical calculations and experimental data at low momentum transfers $|t| \lesssim 0.2$ (GeV/$c)^2$ is found for all observables considered. Moderate discrepancies found in this region are shown to be likely due to uncertainties in the input $NN$ amplitudes. Qualitative agreement at higher momentum transfers is also found for most observables except the tensor ones with mixed $x$ and $z$ polarization components. Possible reasons for observed deviations of the model calculations from the data at $|t| > 0.2$ (GeV/$c)^2$ are discussed.Comment: 13 pages, 9 figure

On the identification of Ti-Ta-Nb-oxides in “wiikites” from Karelia

Purpose. With respect to the nature of Ti-Ta-Nb-oxides, which are included in the mineral associations that have historically gone by the now outdated name of “wiikites”, there is no unanimity of opinion. The main difficulty in identifying them is associated with the complexity of their chemical composition, their metamict structure and the substantial changes in their initial mineral form due to the effects of natural weathering. The aim of this work is the development of methodology to identify Ti-Ta-Nb-oxides corresponding to the mineral formulas AB2O6 and A2B2O7. Methods. The methodology developed in the work includes two experimental approaches: 1) electron probe microanalysis of phases revealed through use of the SEM-BSE method. Based on the resulting data, a hypothesis about the nature of the Ti-Ta-Nb-oxides in a number of wiikite samples is proposed. 2) XRD analysis of those phases that are formed in the course of thermal annealing of samples from 200 to 1000°C. Based on the resulting data here, the previous hypotheses are either accepted or rejected for each sample. Findings. Using this methodology, three “wiikite” samples were analyzed (the experimental codes were Wk-2, Wk-3 and Wk-7). The Ti-Ta-Nb-oxides in two of these wiikites (Wk-2 and Wk-3) were preliminarily determined to be hydroxyyttropyrochlore and hydroxycalciobetafite, respectively. In the third sample (Wk-7), the Ti-Ta-Nb-oxide was classified as polycrase. The results of XRD phase analysis of the annealed samples were compatible with the primary hypotheses that hydroxycalciobetafite and polycrase were the initial minerals in “wiikites” 3 and 7, respectively. Originality. The paper considers the issue of the chemical conditions necessary for the recovery of the original Ti-Ta-Nb-oxide during recrystallization of the metamict structures. This is a problem that has not been substantively addressed in the literature. Also for the first time experimentally proved the existence of the polycrase in “wiikites”. Practical implications. Completed work expands our knowledge of the mineral composition of the granitic pegmatites of the Baltic shield and the possibility of their use both for research purposes and for needs of national economy.Мета. Розробка методології ідентифікації Ti-Ta-Nb-оксидів складного хімічного складу з метаміктною структурою, що відповідають мінеральним формулами АВ2О6 та А2В2О7. Методика. Для розробки методології ідентифікації у роботі використано два експериментальних підходи: 1) рентген-спектральний мікроаналіз фаз, виявлених методом скануючої електронної мікроскопії зразків у назад відображених електронах. На основі отриманих результатів висунута гіпотеза щодо природи Ti-Ta-Nb-оксидів. 2) рентген-дифракційний аналіз фаз, що утворюються в процесі термічного відпалу зразків від 200 до 1000°С. На основі отриманих результатів для кожного зразка первинна гіпотеза приймалася або відкидалася. Результати. З використанням даної методики були вивчені три зразки “віікітів” (шифри зразків: Wk-2, Wk-3 і Wk-7). Наявність Ti-Ta-Nb-оксидів попередньо визначено e двох зразках (Wk-2 і Wk-3) відповідно, як гідроксііттропірохлор та гідроксікальціобетафіт. У третьому зразку (Wk-7) Ti-Ta-Nb діагностований як полікраз. Результати рентген-дифракційного аналізу відпалених зразків підтвердили гіпотези про те, що початковими мінералами у Wk-3 і Wk-7 були гідроксікальціобетафіт і полікраз відповідно. Наукова новизна. Визначено хімічні умови, необхідні для утворення початкового Тi-Ta-Nb під час рекристалізації метаміктної структури, що раніше не розглядалось у відповідній тематичній науковій літературі. Вперше експериментально виявлено присутність у “віікітах” полікраза. Практична значимість. Отримані результати розширюють й доповнюють знання щодо мінерального складу гранітних пегматитів Балтійського щита та надають можливість їх використання в дослідницьких цілях і потребах народного господарства.Цель. Разработка методологии идентификации Ti-Ta-Nb-оксидов сложного химического состава с метамиктной структурой, соответствующих минеральным формулам АВ2О6 и А2В2О7. Методика. Для разработки методологии идентификации в работе использовано два экспериментальных подхода: 1) рентген-спектральный микроанализ фаз, выявленных методом сканирующей электронной микроскопии образцов в обратно отраженных электронах. На основе полученных результатов выдвинута гипотеза о природе Ti-Ta-Nb-оксидов. 2) рентген-дифракционный анализ фаз, образующихся в процессе термического отжига образцов от 200 до 1000°С. На основе полученных результатов для каждого образца первоначальная гипотеза принималась или отвергалась. Результаты. С использованием данной методики были изучены три образца “виикитов” (шифры образцов: Wk-2, Wk-3 и Wk-7). Наличие Ti-Ta-Nb-оксидов предварительно определено в двух образцах (Wk-2 и Wk-3) соответственно, как гидроксииттропирохлор и гидроксикальциобетафит. В третьем образце (Wk-7) Ti-Ta-Nb диагностирован как поликраз. Результаты рентген-дифракционного анализа отожженных образцов подтвердили гипотезы о том, что первоначальными минералами в Wk-3 и Wk-7 были гидроксикальциобетафит и поликраз соответственно. Научная новизна. Определены химические условия, необходимые для образования первоначального Тi-Ta-Nb во время рекристаллизации метамиктной структуры, что ранее не рассматривалось в соответствующих тематических научных литературе. Впервые экспериментально выявлено присутствие в “виикитах” поликраза. Практическая значимость. Полученные результаты расширяют и дополняют знания о минеральном составе гранитных пегматитов Балтийского щита и дают возможности их использования в исследовательских целях и нуждах народного хозяйства.The study was conducted using equipment of the Center of X-ray Diffraction Studies and the Center for Microscopy and Microanalysis of the Research Park at Saint Petersburg State University, as well as the analytical laboratory of OJSC MMC Norilsk Nickel in Saint Petersburg

Germination of pine seed in weightlessness (investigation in Kosmos 782)

An investigation was made of the orientation of aboveground and underground organs of pine plants grown from seed in weightlessness. Orientation was found to be caused by the position of the seeds relative to the substrate surface. Normal growth was manifest only for the plants grown from seed oriented with embryo toward the substrate. Differences were noted between experiment and control as to the quantitative content of nucleoli in the meristematic cells of the rootlets and the shape of cells in the cotyledonous leaflets. No complete agreement was found between data obtained in weightlessness and when gravity was compensated (clinostat treatment with horizontal rotation)

Pine seed germination under weightlessness (a study of the Kosmos 782 satellite)

Orientation of the above and underground organs of pine plants, grown from seeds under weightlessness, was found to be determined by seed position on the substrate. Normal plant growth was observed only if the seed embryos were oriented toward the substrate. Some differences were noted between the experimental and control plants concerning the amount of nucleoli in the root meristematic cells and the cell shape in cotyledonous leaves. No complete similarity was found in experimental results obtained with plants under weightlessness and under compensated gravity. The seeds were obtained from Pinus silvestris, considered to be particularly suitable for this experiment

Theoretical basis for composition of economic strategy for industry development

The article deals with the issues related to analysis of domestic engineering problems with the assessment of the current state of the industry as a whole. Considering the prospects of exiting the current crisis, as well as long-term economic growth we expect general welfare within the sector. As the object of the study the authors have selected the engineering industry of the country. The subject of research is the economic relations between producers and consumers of engineering products, as well as issues of strategy formation and development of the engineering industry. The authors analyzed the state of machine-manufacture and highlighted the problems, the solution of which is most relevant given the government policy of increased import substitution and enhanced productivity. Further analysis was carried out in the sphere of sources of financing and attraction of investment resources for all kinds of enterprises of mechanical engineering, on the basis of which economic development strategy for the industry may be constructed. In addition, the authors propose measures and concrete ways of solving the problems identified by the formation of economic strategy of development of the industry, involving plans of achievement of all the defined targets. As a result of the study authors concluded that the need to stop subsidizing loss-making enterprises, creating a favorable climate for the development of venture companies, in order t introduce innovative technology as soon as possible. These technologies could subsequently be exported together with products of greater added value.peer-reviewe

Nature of S\bm{S}-wave NN\bm{NN} interaction and dibaryon production at nucleonic resonance thresholds

Phase shifts and inelasticity parameters for $NN$ scattering in the partial-wave channels ${}^3S_1$--${}^3D_1$ and ${}^1S_0$ at energies $T_{\rm lab}$ from zero to about 1 GeV are described within a unified $NN$ potential model assuming the formation of isoscalar and isovector dibaryon resonances near the $NN^*(1440)$ threshold. Evidence for these near-threshold resonances is actually found in the recent WASA experiments on single- and double-pion production in $NN$ collisions. There, the excitation of the Roper resonance $N^*(1440)$ exhibits a structure in the energy dependence of the total cross section, which corresponds to the formation of dibaryon states with $I(J^\pi)=0(1^+)$ and $1(0^+)$ at the $NN^*(1440)$ threshold. These two $S$-wave dibaryon resonances may provide a new insight into the nature of the strong $NN$ interaction at low and intermediate energies.Comment: 10 pages, 8 figure