Non-contact method for measurement of the microwave conductivity of graphene

We report a non-contact method for conductivity and sheet resistance measurements of graphene samples using a high Q microwave dielectric resonator perturbation technique, with the aim of fast and accurate measurement of microwave conductivity and sheet resistance of monolayer and few layers graphene samples. The dynamic range of the microwave conductivity measurements makes this technique sensitive to a wide variety of imperfections and impurities and can provide a rapid non-contacting characterisation method. Typically the graphene samples are supported on a low-loss dielectric substrate, such as quartz, sapphire or SiC. This substrate is suspended in the near-field region of a small high Q sapphire puck microwave resonator. The presence of the graphene perturbs both centre frequency and Q value of the microwave resonator. The measured data may be interpreted in terms of the real and imaginary components of the permittivity, and by calculation, the conductivity and sheet resistance of the graphene. The method has great sensitivity and dynamic range. Results are reported for graphene samples grown by three different methods: reduced graphene oxide (GO), chemical vapour deposition (CVD) and graphene grown epitaxially on SiC. The latter method produces much higher conductivity values than the others.Comment: 8 pages, 2 figures and 2 table

Long spin relaxation times in wafer scale epitaxial graphene on SiC(0001)

We developed an easy, upscalable process to prepare lateral spin-valve devices on epitaxially grown monolayer graphene on SiC(0001) and perform nonlocal spin transport measurements. We observe the longest spin relaxation times tau_S in monolayer graphene, while the spin diffusion coefficient D_S is strongly reduced compared to typical results on exfoliated graphene. The increase of tau_S is probably related to the changed substrate, while the cause for the small value of D_S remains an open question.Comment: 16 pages, 3 figures, 1 tabl

EPIDEMIOLOGICAL SITUATION OF DIPHTHERIA IN RUSSIA AND IN THE REGIONS OF THE RUSSIAN FEDERATION SINCE 2005 TO 2011

The analysis of the incidence of diphtheria in the Russian Federation after the second revaccination of adults since 2005 to 2011 is presented. The level of the immunization and. the state of population immunity were studied. The high level of protection against diphtheria was established. It provides positive epidemiological situation against this infection in the country

Dophamine-dependent disorder of conduct of albino rats with sublimate intoxication in the test of extrapolation deliverance

The article presents the results of the examination, of albino rats in the test of extrapolation deliverance (TED) after sublimate intoxication, and madopar-125 injection with previous sublimate intoxication. The aim. of the work was comparative study of conduct of albino rats with sublimate intoxication and at the influence of ma-dopar-125 in combination with sublimate intoxication, in TED. We used TED method in the research that allows to study cognitive abilities of an animal in stress situation. The results were processed with, software package Statistica 6.0 with use of non-parametric Mann — Whitney parameter. Sublimate was introduced subcutaneously in form, of physiological solution in dose 2 mg/kg during 3 days. In 3 days after ending of sublimate explosion we introduced, physiological solution to the rats of the first group 60 minutes before testing and. the rats of the second, group had intraperitoneal introduction, of madopar-125 that was suspended in 0,9 % NaCl with 125 mg/ kg tween-80 in dose 0,6 ml/100 g of animal's body weight. Animals of control group had physiological solution in the same regimen. It was revealed that in 4 days after the ending of sublimate introduction to albino rats experimental animals in comparison with intact ones had significant increase of number of aversive reactions. After sublimate explosion almost one third of albino rats didn't dive under cylinder's edge. In experimental rats average and total duration of immobilization increased while average duration of clambering on cylinder's walls decreased. Latent period of first movement increased sharply both after toxic influence and after introduction of madopar-125 to the rats with sublimate intoxication in comparison with control animals. Introduction of madopar-125 to the rats with sublimate intoxication completely disturbed conduct of deliverance: no animals dove under cylinder's edge. Albino rats with madopar-125 introduction had significant increase of clambering on cylinder's walls in comparison with animals exposed by sublimate without madopar-125 introduction. Besides the number, average and total duration of aversive reactions in form of jumps in comparison, with control group and with rats after sublimate explosion without pharmacological influence significantly increased

Nature behavioral responses, lipid profile and state of cardiovascular system in lead intoxication modelling on the background of hyperlipidemia in albino rats

The article describes the comparative study of the effect of lead intoxication in healthy animals and in terms of modelled hyperlipidemic condition on lipid metabolism, ECG performance, behavior in the test of the extrapolation of deliverance. The study was performed on 40 albino outbred adult male rats. Modeling hyperlipidemic condition was carried out daily by feeding natural unsalted fat at the rate of 8 grams per animal for 16 days. Lead intoxication was created after the atherogenic diet by adding lead acetate into drinking water in a dose of 50 mg/kg of body weight for 4 weeks. To investigate the lipid metabolism was measured in serum total cholesterol, triglycerides, HDL cholesterol, LDL cholesterol. In the test of extrapolation deliverance 70 % of animals with lead intoxication on the lipid load background did not cope with the task versus 40 % of albino rats in the group with lead acetate exposure alone. All control animals successfully solved the problem of the deliverance test. The deterioration of the functioning of the cardiovascular system of rats with lead poisoning on the background of atherogenic diet was manifested by elongation of intraventricular conduction intervals on an electrocardiogram as compared with animals with lead intoxication alone. Disorders of lipid metabolism were manifested by increased levels of LDL cholesterol in rats with lead intoxication on the background of hyperlipidemia to 0.86 (0.69-1.14) mmol/l compared with the value of 0.67 (0.58-0.79) mmol/l in animals with lead intoxication

Ethno-Cultural Code as a Value-Semantic Dominant of the Supply Chain Management in Media Industry

Abstract- The present article is devoted to the actual problem of identifying supply chain management position in real mass media discourses, as well as the question of determining intra-linguistic and extra-linguistic sources of the synergistic binomial of ethno-linguistic culture. This article examines the cultural code, which is the key to understanding ethno-culture, including the unique value-semantic topics of the people's living space, determining the dominant principles of the world perception. The purpose of the article is to analyze representation of the ethno-cultural code in the artistic and mass media discourses. The methodological basis of the research is interpretation of culture as a semiotic space. Used copyright methods include: value-semantic and lingvo-suggestive. The article presents results of the study of cultural code as a value-semantic dominant of artistic and mass-media texts through a communicative and pragmatic analysis of multi-genre texts for disclosure of features of mentality in a cultural code. The authors come to the conclusion that in the semantic structure of a word it is necessary to single out a special component, “cultural meaningâ€, which is formed not by a simple set of individual words, but in text space based on their interaction. The value-sense space created by the cultural code is the basis of entire ethnic community, and deconstruction of the value-sense dominant destroys it

Морфология и эволюционная позиция раннеплиоценовой полёвки Propliomys jalpugensis из Восточной Европы

Propliomys jalpugensis, a fossil rhizodont vole (late Early Pliocene, late Ruscinian, MN15), is revised based on materials from the type locality Kotlovina (southwestern Ukraine). This form is interpreted as a phyletic stage, marked by dental complication of first lower molar and hypsodonty, intermediate between the preceding late Early Pliocene Propliomys kowalskii and P. destinatus, and successive Late Pliocene Propliomys ucrainicus. Molar enamel of P. jalpugensis shows a pattern with the radial enamel in leading edges, occasionally with the incipient lamellar enamel, and the inner radial and outer primitive tangental enamel in trailing and closing edges © RUSSIAN JOURNAL OF THERIOLOGY, 2022Government Council on Grants, Russian FederationWe thank the technical staff of the Geological Institute RAS, Paleontological Institute RAS, and the Ural Center for Shared Use “Modern nanotechnology” SNSM UrFU for the assistance with SEM microscopy and preparing of helped to refine the manuscript. The work was supported by Act 211 Government of the Russian Federation, contract No. 02.A03.21.0006. This work conforms to the scientific plan of the Geological Institute of the Russian Academy of SciencesACKNOWLEDGEMENTS. We thank the technical staff of the Geological Institute RAS, Paleontological Institute RAS, and the Ural Center for Shared Use “Modern nanotechnology” SNSM UrFU for the assistance with SEM microscopy and preparing of samples. We thank the two reviewers for comments that helped to refine the manuscript. The work was supported by Act 211 Government of the Russian Federation, contract No. 02.A03.21.0006. This work conforms to the scientific plan of the Geological Institute of the Russian Academy of Sciences

Enhancing optoelectronic properties of SiC-grown graphene by a surface layer of colloidal quantum dots

We report a simultaneous increase of carrier concentration, mobility and photoresponsivity when SiC-grown graphene is decorated with a surface layer of colloidal PbS quantum dots, which act as electron donors. The charge on the ionised dots is spatially correlated with defect charges on the SiC-graphene interface, thus enhancing both electron carrier density and mobility. This charge-correlation model is supported by Monte Carlo simulations of electron transport and used to explain the unexpected 3-fold increase of mobility with increasing electron density. The enhanced carrier concentration and mobility give rise to Shubnikov-de Haas oscillations in the magnetoresistance, which provide an estimate of the electron cyclotron mass in graphene at high densities and Fermi energies up to 1.2 × 1013 cm-2 and 400 meV, respectively