Nontrivial dependence of dielectric stiffness and SHG on dc bias in relaxors and dipole glasses

Dielectric permittivity and Second Harmonic Generation (SHG) studies in the field-cooled mode show a linear dependence of dielectric stiffness (inverse dielectric permittivity) on dc bias in PMN-PT crystals and SHG intensity in KTaO$_{3}$:Li at small Li concentrations. We explain this unusual result in the framework of a theory of transverse, hydrodynamic-type, instability of local polarization.Comment: 5 figure

Hard Parton Rescatterings and Minijets in Nuclear Collisions at LHC

The average number of minijets and the corresponding transverse energy produced in heavy ion collisions are evaluated by including explicitly semi-hard parton rescatterings in the dynamics of the interaction. At the LHC semi-hard rescatterings have a sizable effect on global characteristics of the typical inelastic event. An interesting feature is that the dependence on the cutoff which separates soft and hard parton interactions becomes less critical after taking rescatterings into account.Comment: 14 pages, 3 figures. Enlarged discussion in sect.1 and 4; 1 figure added. To be published in Phys.Rev.

Experimental Study of Two-Phase Thermosyphons of the Thermoelectric Cooling Unit

Проведены экспериментальные исследования теплопередающей способности двухфазных термосифонов, заправленных фреоном 134А. Термосифоны изготовлены из нержавеющей стали, имеют длину 400 мм и внутренний диаметр 10,5 мм, протяженность зоны испарения составляла 200 мм, а длина конденсатора – 60 мм. Приведены данные измерений температурного состояния и теплопередающих характеристик термосифонов в зависимости от передаваемого теплового потока, угла наклона от вертикали и температуры теплоносителя системы теплоотводаExperimental studies of the heat transfer capacity of two- phase thermosiphons filled with Freon 134A have been carried out. Thermosyphons are made of stainless steel, have a length of 400 mm and an internal diameter of 10.5 mm, the length of the evaporation zone was 200 mm, and the length of the condenser was 60 mm.The data of measurements of the temperature state and heat transfer characteristics of thermosiphons depending on the transferred heat flux, the angle of inclination from the vertical and the temperature of the coolant of the heat removal system are give

Катушечновильчатый высаживающий аппарат для ориентированной посадки лукасевка

Seed onion planting is fundamental operation at realization of technological process of onions cultivation. The main lack of bulb planters is a group picking of bulbs from overall mass by planting devices, but not single-piece wherefore planting of bulbs in demanded orientation is problematic. It was noted that when developing of bulb planters for planting of bulbous cultures it is necessary to provide optimum balance between productivity and quality indicators of planting: uniformity of distribution along a row and quantity of the bulbs with a stem below. It was established that the roller feeds are most perspective. There were defined their main shortcomings: seeds damage and lack of bulbs stem below orientation. Thus, uniformity of distribution makes about 40 percent. A special device with the orienting funnels was suggested. A forked-roller feed for the oriented seed onion planting for the oriented planting of seed onion carrying out single-piece picking of bulbs from the bunker and their giving in seed tube at below stem orientation for planting in a furrow was worked out. Researches confirmed that the suggested design provides stable performance of technological process of bulbs planting.Посадка лука-севка - основополагающая операция при реализации технологического процесса возделывания лука. Основным недостатком машин для посадки лука-севка остается групповой отбор луковиц из общей массы высаживающими аппаратами, а не поштучный, из-за чего посадка луковиц в требуемом положении затруднительна. Отметили, что при разработке высаживающих аппаратов для посадки луковых культур необходимо обеспечить оптимальный баланс между производительностью и качественными показателями посадки (равномерность распределения луковиц вдоль рядка и количество луковиц, посаженных донцем вниз). Установили, что наиболее перспективными являются катушечные высевающие аппараты. Определили их основные недостатки - повреждение семян и отсутствие ориентации луковиц донцем вниз, при этом равномерность распределения составляет около 40 процентов. Предложили ориентирующее устройство - ориентирующие воронки. Разработали катушечно-вильчатый высаживающий аппарат для ориентированной посадки лука-севка, осуществляющий поштучный отбор луковиц из бункера и подачу их в семяпровод донцем вниз для сбрасывания в борозду. Исследования подтвердили, что предложенная конструкция обеспечивает стабильное выполнение технологического процесса по посадке луковиц

Dynamics of Hot Bulk QCD Matter: from the Quark-Gluon Plasma to Hadronic Freeze-Out

We introduce a combined macroscopic/microscopic transport approach employing relativistic hydrodynamics for the early, dense, deconfined stage of the reaction and a microscopic non-equilibrium model for the later hadronic stage where the equilibrium assumptions are not valid anymore. Within this approach we study the dynamics of hot, bulk QCD matter, which is expected to be created in ultra-relativistic heavy ion collisions at the SPS, the RHIC and the LHC. Our approach is capable of self-consistently calculating the freeze-out of the hadronic system, while accounting for the collective flow on the hadronization hypersurface generated by the QGP expansion. In particular, we perform a detailed analysis of the reaction dynamics, hadronic freeze-out, and transverse flow.Comment: 55 pages, 15 figure

Impact-parameter dependent nuclear parton distribution functions: EPS09s and EKS98s and their applications in nuclear hard processes

We determine the spatial (impact parameter) dependence of nuclear parton distribution functions (nPDFs) using the $A$-dependence of the spatially independent (averaged) global fits EPS09 and EKS98. We work under the assumption that the spatial dependence can be formulated as a power series of the nuclear thickness functions $T_A$. To reproduce the $A$-dependence over the entire $x$ range we need terms up to $[T_A]^4$. As an outcome, we release two sets, EPS09s (LO, NLO, error sets) and EKS98s, of spatially dependent nPDFs for public use. We also discuss the implementation of these into the existing calculations. With our results, the centrality dependence of nuclear hard-process observables can be studied consistently with the globally fitted nPDFs for the first time. As an application, we first calculate the LO nuclear modification factor $R^{1jet}_{AA}$ for primary partonic-jet production in different centrality classes in Au+Au collisions at RHIC and Pb+Pb collisions at LHC. Also the corresponding central-to-peripheral ratios $R_{CP}^{1jet}$ are studied. We also calculate the LO and NLO nuclear modification factors for single inclusive neutral pion production, $R_{dAu}^{\pi^0}$, at mid- and forward rapidities in different centrality classes in d+Au collisions at RHIC. In particular, we show that our results are compatible with the PHENIX mid-rapidity data within the overall normalization uncertainties given by the experiment. Finally, we show our predictions for the corresponding modifications $R_{pPb}^{\pi^0}$ in the forthcoming p+Pb collisions at LHC.Comment: 36 page

Hard X-ray Bursts Detected by the IBIS Telescope Onboard the INTEGRAL Observatory in 2003-2004

All of the observations performed with the IBIS telescope onboard the INTEGRAL observatory during the first one and a half years of its in-orbit operation (from February 10, 2003, through July 2, 2004) have been analyzed to find X-ray bursts. IBIS/ISGRI detector lightcurves total count rate in the energy range 15-25 keV revealed 1077 bursts of durations from ~5 to ~500 s detected with a high statistical significance (only one event over the entire period of observations could be detected by a chance with a probability of 20%). Apart from the events associated with cosmic gamma-ray bursts (detected in the field of view or passed through the IBIS shield), solar flares, and activity of the soft gamma repeater SGR1806-20, we were able to localize 105 bursts and, with one exception, to identify them with previously known persistent or transient X-ray sources (96 were identified with known X-ray bursters). In one case, the burst source was a new burster in a low state. We named it IGR J17364-2711. Basic parameters of the localized bursts and their identifications are presented in the catalog of bursts. Curiously enough, 61 bursts were detected from one X-ray burster - GX 354-0. The statistical distributions of bursts in duration, maximum flux, and recurrence time have been analyzed for this source. Some of the bursts observed with the IBIS/ISGRI telescope were also detected by the JEM-X telescope onboard the INTEGRAL observatory in the standard X-ray energy range 3-20 keV.Comment: 30 pages, 9 figure

Circularly polarized electroluminescence from silicon nanostructures heavily doped with boron

The circularly polarized electroluminescence (CPEL) from silicon nanostructures which are the p-type ultra-narrow silicon quantum well (Si-QW) confined by {\delta}-barriers heavily doped with boron, 5 10^21 cm^-3, is under study as a function of temperature and excitation levels. The CPEL dependences on the forward current and temperature show the circularly polarized light emission which appears to be caused by the exciton recombination through the negative-U dipole boron centers at the Si-QW {\delta}-barriers interface