Isovector soft dipole mode in 6Be

By using the 1H(6Li,6Be)n charge-exchange reaction, continuum states in 6Be were populated up to E_t=16 MeV, E_t being the 6Be energy above its three-body decay threshold. In kinematically complete measurements performed by detecting alpha+p+p coincidences, an E_t spectrum of high statistics was obtained, containing approximately ~5x10^6 events. The spectrum provides detailed correlation information about the well-known 0^+ ground state of 6Be at E_t=1.37 MeV and its 2^+ state at E_t=3.05 MeV. Moreover, a broad structure extending from 4 to 16 MeV was observed. It contains negative parity states populated by Delta L=1 angular momentum transfer without other significant contributions. This structure can be interpreted as a novel phenomenon, i.e. the isovector soft dipole mode associated with the 6Li ground state. The population of this mode in the charge-exchange reaction is a dominant phenomenon for this reaction, being responsible for about 60% of the cross section obtained in the measured energy range.Comment: 8 pages, 7 figure

Conservation of grape genetic resources in the system in vitro

Conservation of grape genetic resources in the system in vitro can be a contribution to ampelographic collections, and a source of their replenishment with healthy planting material. The goal of the study is to create a vegetative in vitro collection of plants of promising grape varieties and clones, optimize the conditions for maintaining samples. The basis for obtaining, cultivating, clonal micro-propagating of grape plants is the research and development of the Institute Magarach. At the moment, the collection is represented by 144 samples of grape varieties and clones. Samples of the collection are kept in a state of active growth, slow growth and true dormancy. Previous studies followed to establishment of five modes to maintain grape plants in the system in vitro. Changes in the parameters of individual factors affecting morphogenesis made it possible to slow down growth processes and reduce the number of re-plantings. The most promising mode to conserve samples is the fifth one (this method is patented). As a result of the research carried out in the Institute Magarach, a vegetative collection of plants in vitro of promising grape varieties and clones was created. It includes Crimean autochthonous varieties and varieties of the Institute Magarach breeding. The developed modes of collection conservation allow slowing down growth processes and maintaining plants in a state of true dormancy without re-planting for one to two years

Effect of CH4, H2, Ar, Carbon Additives and the Shape of a Reactor on the Porous Structure of Acetylene Black Formed During the Decomposition of Acetylene

Abstract The porous structure of acetylene black was studied depending on the conditions of its preparation in the decomposition of acetylene: at various pressures in a tubular reactor of limited volume, decomposition of acetylene in mixtures with CH4, H2, or Ar and decomposition of acetylene in the presence of acetylene black and in reactors of various shapes. It has been found that the decomposition of pure acetylene with an increase in pressure from 2.35 to 5 bar increases the surface area of acetylene black from 75 to 125 m2/g, and the average particle size decreases from 36 to 22 nm. Additives of CH4, H2 or Ar inhibit the decomposition of acetylene, while the degree of inhibition decreases in the following sequence: H2 > CH4 > Ar. Relatively small additions of hydrogen block the decomposition of acetylene, practically without affecting the size of acetylene black particles. On the contrary, addition of methane leads to a significant increase in the average size of acetylene black particles to 55 nm and a corresponding decrease in the specific surface area to 57 m2/g. Addition of argon to acetylene qualitatively affects the porous structure of acetylene black in the same way as reducing the pressure of acetylene. During the decomposition of acetylene in the presence of acetylene black remaining in the reactor after the previous decomposition, a nonmonotonic change in the specific surface area and size of acetylene black particles was observed. It was shown in experiments with reactors different in shape but identical in volume that, with a decrease in the linear dimensions of the reaction vessel (length/diameter ratio), the surface area of the formed acetylene black increases rather significantly, and the average size of acetylene black particles decreases