Extreme plasma states in laser-governed vacuum breakdown

Triggering vacuum breakdown at the upcoming laser facilities can provide rapid electron-positron pair production for studies in laboratory astrophysics and fundamental physics. However, the density of the emerging plasma should seemingly stop rising at the relativistic critical density, when the plasma becomes opaque. Here we identify the opportunity of breaking this limit using optimal beam configuration of petawatt-class lasers. Tightly focused laser fields allow plasma generation in a small focal volume much less than ${\lambda}^3$, and creating extreme plasma states in terms of density and produced currents. These states can be regarded as a new object of nonlinear plasma physics. Using 3D QED-PIC simulations we demonstrate the possibility of reaching densities of more than $10^{25}$ cm$^{-3}$, which is an order of magnitude higher than previously expected. Controlling the process via the initial target parameters gives the opportunity to reach the discovered plasma states at the upcoming laser facilities

The Study of the Properties of Uranium Dioxide Pellets Depending on the Parameters of Pressing and Sintering

The paper presents dilatometric research of uranium dioxide pellets, fabricated by compaction at different pressure values. Temperature observed at sintering start is determined and it is pointed out that this temperature doesn’t depend on compaction pressure. Keywords: uranium dioxide, compaction, sintering, dilatometry, shrink curves, geometric density, pycnometric density

The investigation of quasi-characteristic radiation of electrons channeled along the charged axes in the crystals of zinc blende

For slight relativistic electrons moving along the main charged [100] and [110] axes in the crystals of zinc blende there was made a numerical calculation of the transverse energy levels and corresponding wave functions. It was done the calculation and the comparison of quasi-characteristic radiation spectra for these axe

Origin of magnetic moments and presence of a resonating valence bond state in Ba2_2YIrO6_6

While it was speculated that 5$d^4$ systems would possess non-magnetic $J$~=~0 ground state due to strong Spin-Orbit Coupling (SOC), all such systems have invariably shown presence of magnetic moments so far. A puzzling case is that of Ba$_2$YIrO$_6$, which in spite of having a perfectly cubic structure with largely separated Ir$^{5+}$ ($d^4$) ions, has consistently shown presence of weak magnetic moments. Moreover, we clearly show from Muon Spin Relaxation ($\mu$SR) measurements that a change in the magnetic environment of the implanted muons in Ba$_2$YIrO$_6$ occurs as temperature is lowered below 10~K. This observation becomes counterintuitive, as the estimated value of SOC obtained by fitting the RIXS spectrum of Ba$_2$YIrO$_6$ with an atomic $j-j$ model is found to be as high as 0.39~eV, meaning that the system within this model is neither expected to possess moments nor exhibit temperature dependent magnetic response. Therefore we argue that the atomic $j-j$ coupling description is not sufficient to explain the ground state of such systems, where despite having strong SOC, presence of hopping triggers delocalisation of holes, resulting in spontaneous generation of magnetic moments. Our theoretical calculations further indicate that these moments favour formation of spin-orbital singlets in the case of Ba$_2$YIrO$_6$, which is manifested in $\mu$SR experiments measured down to 60~mK.Comment: 20 Pages, 7 Figure

Features of testing a powerful integrated circuit or semiconductor device in the temperature range

Тестирование - это измерение электрических параметров микросхем и полупроводниковых приборов и проведение функционального контроля микросхем. Поскольку мощные микросхемы и полупроводниковые приборы являются тепловыделяющими, их тестирование должно проводиться с учетом перегрева кристалла. В работе рассмотрены возможные способы их тестирования, в том числе учитывающие перегрев кристалла. Testing is the measurement of electrical parameters of microcircuits and semiconductor devices and carrying out functional control of microcircuits. Since high-power chips and semiconductor devices are heatgenerating, their testing should be carried out taking into account the overheating of the crystal. The paper considers possible ways of testing them, including taking into account the overheating of the crystal

Studies to elucidate the effect and antiapoptotic mechanism of 2-ethyl-3-hydroxy-6- methylpyridine-n-acetyltaurinate in a rat model of retinal ischemia-reperfusion

To study the retinoprotective effect and antiapoptotic mechanism of 2-Ethyl-3-hydroxy-6-methyl-pyridine-Nacetyltaurinate (EHMP-NAT) in a rat model of retinal ischemia-reperfusio

Live Birth of a Healthy Child in a Couple with Identical mtDNA Carrying a Pathogenic c.471_477delTTTAAAAinsG Variant in the MOCS2 Gene.

Molybdenum cofactor deficiency type B (MOCODB; #252160) is an autosomal recessive metabolic disorder that has only been described in 37 affected patients. In this report, we describe the presence of an in-frame homozygous variant (c.471_477delTTTAAAAinsG) in the MOCS2 gene in an affected child, diagnosed with Ohtahara syndrome according to the clinical manifestations. The analysis of the three-dimensional structure of the protein and the amino acid substitutions suggested the pathogenicity of this mutation. To prevent transmitting this mutation to the next generation, we used preimplantation genetic testing for the monogenic disorders (PGT-M) protocol to select MOCS2 gene mutant-free embryos for transfer in an in vitro fertilization (IVF) program. As a result, a healthy child was born. Interestingly, both parents of the proband shared an identical mitochondrial (mt) DNA control region, assuming their close relationship and thus suggesting that both copies of the nuclear rare variant c.471_477delTTTAAAAinsG may have been transmitted from the same female ancestor. Our estimation of the a priori probability of meeting individuals with the same mtDNA haplotype confirms the assumption of a possible distant maternal relationship among the proband's direct relatives