543 research outputs found
Analytic Invariant Charge in QCD
This paper gives an overview of recently developed model for the QCD analytic
invariant charge. Its underlying idea is to bring the analyticity condition,
which follows from the general principles of local Quantum Field Theory, in
perturbative approach to renormalization group (RG) method. The concrete
realization of the latter consists in explicit imposition of analyticity
requirement on the perturbative expansion of function for the strong
running coupling, with subsequent solution of the corresponding RG equation. In
turn, this allows one to avoid the known difficulties originated in
perturbative approximation of the RG functions. Ultimately, the proposed
approach results in qualitatively new properties of the QCD invariant charge.
The latter enables one to describe a wide range of the strong interaction
processes both of perturbative and intrinsically nonperturbative nature.Comment: Invited review article; 46 pages, 14 EPS figure
Transport properties and the anisotropy of Ba_{1-x}K_xFe_2As_2 single crystals in normal and superconducting states
The transport and superconducting properties of Ba_{1-x}K_xFe_2As_2 single
crystals with T_c = 31 K were studied. Both in-plane and out-of plane
resistivity was measured by modified Montgomery method. The in-plane
resistivity for all studied samples, obtained in the course of the same
synthesis, is almost the same, unlike to the out-of plane resistivity, which
differ considerably. We have found that the resistivity anisotropy
\gamma=\rho_c /\rho_{ab} is almost temperature independent and lies in the
range 10-30 for different samples. This, probably, indicates on the extrinsic
nature of high out-of-plane resistivity, which may appear due to the presence
of the flat defects along Fe-As layers in the samples. This statement is
supported by comparatively small effective mass anisotropy, obtained from the
upper critical field measurements, and from the observation of the so-called
"Friedel transition", which indicates on the existence of some disorder in the
samples in c-direction.Comment: 5 pages, 5 figure
Wildfire evidence from the Middle and Late Permian Hanxing Coalfield, North China Basin
Earth has a long geological history and palaeo-wildfire is one of the key factors which is responsible for the evolution and extinction of our earth systems. The most important extinction of our earth systems is the Permian-Triassic mass extinction. The objective of this paper is to evaluate the product of wildfire in terms of distribution and occurrences from the Late Permian North China basin. Fourteen rock samples were collected from a drill core of Hanxing Coalfield of North China basin. The samples were analyzed by macro and micro petrography, Scanning Electron Microscopy (SEM), Gas Chromatography (GC) and Gas Chromatography–Mass Spectrometry (GC-MS) in order to study the evidence of wildfire. Charcoal (inertinite) particles are observed in the samples, which established the occurrences of wildfire during the upper Middle and Late Permian time in North China. Additionally, high-molecular-weight Polycyclic Aromatic Hydrocarbons (PAHs) were detected in the studied samples which also reinforce the presence of palaeo–wildfire events in the North China basin in Late Permian due to the fact that these aromatic compounds were formed under high temperatures
Computer package DIZET v. 6.45
The new version of the DIZET electroweak library is described. Changes and
additional code features concerning the previous version are explained. The
software allows one to make state-of-the-art theoretical predictions for
pseudo-observable quantities, including higher-order radiative corrections. The
current version of the DIZET library v. 6.45 incorporates advanced recent
results of theoretical calculations. Numerical comparisons with the results of
the previous version are performed. Estimates of theoretical uncertainties are
discussed.Comment: 14 pages, 3 figures, 8 table
The synthesis of esters of phosphinic acids containing heterocyclic radicals - Communication 7. Esters of phosphinic acid with mono- and di-oxidoquinoxalinic radicals
By the interaction of the mono-N- and di-N-oxides of 2,3-di-(w-bromomethyl)-quinoxallne with trialkyl phosphites there was synthesized a series of esters of phosphinic acid containing mono-N- and di-N-oxidoquinoxalinic radicals; some of their properties were studied. © 1961 Consultants Bureau
Wildfire evidence from the Middle and Late Permian Hanxing Coalfield, North China Basin
Earth has a long geological history and palaeo-wildfire is one of the key factors which is responsible for the evolution and extinction of our earth systems. Thus, it is important to establish the history in order to gain more understanding about Permian-Triassic mass extinction. It is also related to the carbon cycle of the earth in which the whole life system depends. The objective of this paper is to evaluate the product of wildfire in terms of distribution and occurrences from the Late Permian North China basin. Hence, fourteen (14) rock samples were collected from a drill core of Hanxing Coalfield of North China basin. The samples were analyzed by macro and micro petrography, scanning electron microscopy (SEM), gas chromatography (GC), and gas chromatography-mass spectrometry (GC-MS) in order to study the evidence of wildfire. Charcoal (inertinite) particles are observed in the samples, which established the occurrences of wildfire during the Upper Middle and Late Permian time in North China. Additionally, high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) were detected in the studied samples which also reinforce the presence of palaeo - wildfire events in the North China basin in Late Permian due to the fact that the these aromatic compounds were formed under high temperatures
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