388 research outputs found
Effect of low temperatures on osserous and cartilaginous tissues
The use of extreme cold to treat tumoral afflictions of the extremities is discussed. Cryogenic methods and instruments are discussed, and the levels of accumulated knowledge in this area (as well as the areas still in question) are evaluated. The overall promise for cryogenic methods of treatment is acknowledged, and areas which need further development are noted
Pulse cathodo- and thermoluminescence of alumina ceramic with manganese
Alumina ceramics with manganese in concentration range 0.001-18 wt. % are synthesized. Luminescent properties of obtained ceramics at temperatures 1500-1700°C of sintering in vacuum are investigated. An increase in the manganese concentration leads to quenching of the pulse cathodoluminescence band at 420 nm and the main dosimetric peak at 460 K. The intensity of luminescence in the 676 nm band at manganese concentrations of more than 1 wt. % and the TL yield for all the observed peaks increase when annealing temperature rises. Sublinear increase in TL intensity with a growing dose is observed in the range of 3-1000 Gy in 460 and 620 K peaks. © Published under licence by IOP Publishing Ltd.The reported study was funded by RFBR according to the research project № 18-33-00085
Probing and Identifying New Physics Scenarios at International Linear Collider
Numerous non-standard dynamics are described by contact-like effective interactions that can manifest themselves in e+e- collisions only through deviations of the observables (cross sections, asymmetries) from the Standard Model predictions. If such a deviation were observed, it would be important to identify the actual source among the possible non-standard interactions as many different new
physics scenarios may lead to very similar experimental signatures. Here we study the possibility of uniquely identifying the indirect effects of s-channel sneutrino exchange, as predicted by supersymmetric theories with R-parity violation, against other new physics scenarios in process e+e- — µ+µ- at the International Linear Collider. To evaluate the identification reach on sneutrino exchange, we use as basic observable a double polarization asymmetry, A doubie-Also, we examine the effects of neutrino and electron mixing with exotic heavy leptons in the process e+e- — W+W- within E6 models, in particular, the possibility of uniquely distinguishing and identifying such effects ofheavy neutral lepton exchange from Z —Z’ mixing
Pecularities of Hall effect in GaAs/{\delta}<Mn>/GaAs/In\timesGa1-\timesAs/GaAs (\times {\approx} 0.2) heterostructures with high Mn content
Transport properties of GaAs/{\delta}/GaAs/In\timesGa1-\timesAs/GaAs
structures containing InxGa1-xAs (\times {\approx} 0.2) quantum well (QW) and
Mn delta layer (DL) with relatively high, about one Mn monolayer (ML) content,
are studied. In these structures DL is separated from QW by GaAs spacer with
the thickness ds = 2-5 nm. All structures possess a dielectric character of
conductivity and demonstrate a maximum in the resistance temperature dependence
Rxx(T) at the temperature {\approx} 46K which is usually associated with the
Curie temperature Tc of ferromagnetic (FM) transition in DL. However, it is
found that the Hall effect concentration of holes pH in QW does not decrease
below TC as one ordinary expects in similar systems. On the contrary, the
dependence pH(T) experiences a minimum at T = 80-100 K depending on the spacer
thickness, then increases at low temperatures more strongly than ds is smaller
and reaches a giant value pH = (1-2)\cdot10^13 cm^(-2). Obtained results are
interpreted in the terms of magnetic proximity effect of DL on QW, leading to
induce spin polarization of the holes in QW. Strong structural and magnetic
disorder in DL and QW, leading to the phase segregation in them is taken into
consideration. The high pH value is explained as a result of compensation of
the positive sign normal Hall effect component by the negative sign anomalous
Hall effect component.Comment: 19 pages, 6 figure
Structural and transport properties of GaAs/delta<Mn>/GaAs/InxGa1-xAs/GaAs quantum wells
We report results of investigations of structural and transport properties of
GaAs/Ga(1-x)In(x)As/GaAs quantum wells (QWs) having a 0.5-1.8 ML thick Mn
layer, separated from the QW by a 3 nm thick spacer. The structure has hole
mobility of about 2000 cm2/(V*s) being by several orders of magnitude higher
than in known ferromagnetic two-dimensional structures. The analysis of the
electro-physical properties of these systems is based on detailed study of
their structure by means of high-resolution X-ray diffractometry and
glancing-incidence reflection, which allow us to restore the depth profiles of
structural characteristics of the QWs and thin Mn containing layers. These
investigations show absence of Mn atoms inside the QWs. The quality of the
structures was also characterized by photoluminescence spectra from the QWs.
Transport properties reveal features inherent to ferromagnetic systems: a
specific maximum in the temperature dependence of the resistance and the
anomalous Hall effect (AHE) observed in samples with both "metallic" and
activated types of conductivity up to ~100 K. AHE is most pronounced in the
temperature range where the resistance maximum is observed, and decreases with
decreasing temperature. The results are discussed in terms of interaction of
2D-holes and magnetic Mn ions in presence of large-scale potential fluctuations
related to random distribution of Mn atoms. The AHE values are compared with
calculations taking into account its "intrinsic" mechanism in ferromagnetic
systems.Comment: 15 pages, 9 figure
Searches for and Identification Effects of Extra Spatial Dimensions in Lepton Pair Production at the LHC
Arkani-Hamed, Dimopoulous, and Dvali have proposed a model (ADD) of low-scale quantum gravity featuring large extra dimensions. In this model, the exchange of Kaluza-Klein towers of gravitons can enhance the production rate of lepton pairs at high invariant mass in proton-proton collisions at the LHC. By considering the present and future LHC energy regimes, we reanalyse the potential of the LHC to
discover the effects of large extra dimensions and to discriminate between various theoretical models. Specifically, in latter case we explore the capability of the LHC to distinguish spin-2 Kaluza-Klein towers of gravitons exchange from other new physics effects which might be conveniently parametrized by the four-fermion contact interactions. We find that the LHC with planned energy 14 TeV and luminosity 100 fb-1will be capable of discovering (and identifying) graviton exchange effects in the large extra dimensions with the cutoff parameter of order Ms = 6.2 TeV (4.8 TeV) for d= 6 and Ms = 8.8 TeV (6.8 TeV) for d = 3
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