307 research outputs found
Stable Spin Precession at one Half of Equilibrium Magnetization in Superfluid 3He-B
New stable modes of spin precession have been observed in superfluid 3He-B.
These dynamical order parameter states include precession with a magnetization
S=pS_{eq} which is different from the equilibrium value S_{eq}. We have
identified modes with p=1, 1/2 and \approx 0. The p=1/2 mode is the second
member of phase correlated states of a spin superfluid. The new states can be
excited in the temperature range 1-T/T_c \lesssim 0.02 where the energy
barriers between the different local minima of the spin-orbit energy are small.
They are stable in CW NMR due to low dissipation close to T_c.Comment: submitted to Physical Review Letters, 4 pages, revtex, 4 Figures in
ftp://boojum.hut.fi/pub/publications/lowtemp/LTL-96005.p
Simulation of neutron transport for the purpose of neutron filters optimization in the pulsed neutron logging apparatus
© 2006-2015 Asian Research Publishing Network (ARPN). Numerical modeling of thermal neutron filters, which are an integral part of the apparatus of pulsed neutron logging (PNL), has been carried out. Many models of filters were created. The neutrons slowing down and absorption processes in filters was analyzed. Optimum structure and dimensions of neutron filters was offered
Problems with the use of pneumatic screw pumps to transport bulk cargo
An analysis is made of the performance of pneumatic screw pumps at the Bereznikovsky Soda Plant in order be able to transport light soda along a prescribed route and make use of a new nozzle section to make the pumps' operation more reliable. Specific recommendations are made to increase the throughput and reliability of pneumatic screw pumps. The expediency of replacing long lines of screw pumps by chamber pumps is also discussed. © 2013 Springer Science+Business Media New York
ДЕВОН-КАМЕННОУГОЛЬНЫЙ МАГМАТИЗМ И ОРУДЕНЕНИЕ ЮЖНО-УРАЛЬСКОЙ АККРЕЦИОННО-КОЛЛИЗИОННОЙ СИСТЕМЫ
The oceanic stage in the history of the South Urals completed in the Ordovician – Early Silurian. The Ordovician through Devonian events in the region included the formation of an island arc in the East Ural zone from the Middle Ordovician to Silurian; westward motion of the subduction zone in the Late Silurian – Early Devonian and the origin of a trench along the Main Ural Fault and the Uraltau Uplift; volcanic eruptions and intrusions in the Magnitogorsk island arc system in the Devonian. The Middle-Late Paleozoic geodynamic evolution of uralides and altaides consisted in successive alternation of subduction and collisional settings at the continent-ocean transition. The greatest portion of volcanism in the major Magnitogorsk zone was associated with subduction and correlated in age and patterns of massive sulfide mineralization (VMS) with Early – Middle Devonian ore-forming events in Rudny Altai. Within-plate volcanism at the onset of volcanic cycles records the Early (D1e2) and Middle (D2ef2) Devonian slab break off. The volcanic cycles produced, respectively, the Buribay and Upper Tanalyk complexes with VMS mineralization in the Late Emsian; the Karamalytash complex and its age equivalents in the Late Eifelian – Early Givetian, as well as the lower Ulutau Formation in the Givetian. Slab break off in the Late Devonian – Early Carboniferous obstructed the Magnitogorsk island arc and supported asthenospheric diapirism. A new subduction zone dipping westward and the Aleksandrovka island arc formed in the Late Devonian – Early Carboniferous. The Early Carboniferous collision and another event of obstructed subduction led to a transform margin setting corresponding to postcollisional relative sliding of plates that produced another slab tear. Postcollisional magmatism appears as alkaline gabbro-granitic intrusives with related rich Ti-magnetite mineralization (C1). Transform faulting persisted in the Middle Carboniferous through Permian, when the continent of Eurasia completed its consolidation. The respective metallogenic events included formation of Cu-Ni picritic dolerites (C2–3), as well as large-scale gold and Mo-W deposits in granites (P1–2).Завершение океанической стадии на Южном Урале произошло в ордовик – раннесилурийское время. В среднем ордовике в Восточно-Уральской зоне начала формироваться среднеордовикско-силурийская островная дуга. В позднем силуре – раннем девоне произошел перескок зоны субдукции на запад, формирование глубоководного желоба в зоне Главного Уральского разлома – Уралтауского антиклинория и началось образование вулкано-интрузивных формаций Магнитогорской островодужной системы (D1–D3). В среднепозднепалеозойской геодинамической эволюции уралид и алтаид произошло последовательное чередование субдукционных и трансформно-коллизионных обстановок в зоне перехода континент – океан. На Южном Урале с субдукционной обстановкой связан главный объем вулканических ассоциаций Магнитогорской мегазоны. В раннем (D1e2) и среднем (D2ef2) девоне произошли разрывы слэба, фиксирующиеся проявлениями внутриплитного вулканизма, приуроченного к начальным этапам раннедевонского позднеэмсского и позднеэйфельско-раннеживетского колчеданоносных вулканических циклов. В позднем девоне – раннем карбоне произошла блокировка Магнитогорской островной дуги с разрывом слэба, и, как следствие, – главный этап астеносферного диапиризма. На рубеже позднего девона – раннего карбона сформировалась новая зона субдукции западного падения и возникла Александровская редуцированная островная дуга. Раннекаменноугольная коллизия и повторная блокировка субдукционной зоны привели к трансформной обстановке, отвечавшей постколлизионному скольжению литосферных плит, и вновь – к появлению астеносферного окна («slab-tear»). В этой обстановке были сформированы габбро-гранитные интрузивы повышенной щелочности и связанные с ними Ti-Mgt месторождения мирового класса (С1). Трансформная геодинамическая обстановка оставалась ведущей на протяжении среднего карбона – перми, когда произошла окончательная консолидация Евразийского континента
Observation of narrow baryon resonance decaying into in pA-interactions at with SVD-2 setup
SVD-2 experiment data have been analyzed to search for an exotic baryon
state, the -baryon, in a decay mode at on IHEP
accelerator. The reaction with a limited multiplicity was
used in the analysis. The invariant mass spectrum shows a resonant
structure with and . The statistical significance of this peak was estimated to be of . The mass and width of the resonance is compatible with the recently
reported - baryon with positive strangeness which was predicted as an
exotic pentaquark () baryon state. The total cross section for
production in pN-interactions for was estimated to be
and no essential deviation from A-dependence for inelastic
events was found.Comment: 8 pages, 7 figures, To be submitted to Yadernaya Fizika. v3-v5 - Some
references added, minor typos correcte
Interferometry of Direct Photons in Central 280Pb+208Pb Collisions at 158A GeV
Two-particle correlations of direct photons were measured in central
208Pb+208Pb collisions at 158 AGeV. The invariant interferometric radii were
extracted for 100<K_T<300 MeV/c and compared to radii extracted from charged
pion correlations. The yield of soft direct photons, K_T<300 MeV/c, was
extracted from the correlation strength and compared to theoretical
calculations.Comment: 5 pages, 4 figure
Azimuthal Anisotropy of Photon and Charged Particle Emission in Pb+Pb Collisions at 158 A GeV/c
The azimuthal distributions of photons and charged particles with respect to
the event plane are investigated as a function of centrality in Pb + Pb
collisions at 158 A GeV/c in the WA98 experiment at the CERN SPS. The
anisotropy of the azimuthal distributions is characterized using a Fourier
analysis. For both the photon and charged particle distributions the first two
Fourier coefficients are observed to decrease with increasing centrality. The
observed anisotropies of the photon distributions compare well with the
expectations from the charged particle measurements for all centralities.Comment: 8 pages and 6 figures. The manuscript has undergone a major revision.
The unwanted correlations were enhanced in the random subdivision method used
in the earlier version. The present version uses the more established method
of division into subevents separated in rapidity to minimise short range
correlations. The observed results for charged particles are in agreement
with results from the other experiments. The observed anisotropy in photons
is explained using flow results of pions and the correlations arising due to
the decay of the neutral pion
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