1,413 research outputs found
Electron-electron interaction in carbon nanostructures
The electron-electron interaction in carbon nanostructures was studied. A new
method which allows to determine the electron-electron interaction constant
from the analysis of quantum correction to the magnetic
susceptibility and the magnetoresistance was developed. Three types of carbon
materials: arc-produced multiwalled carbon nanotubes (arc-MWNTs), CVD-produced
catalytic multiwalled carbon nanotubes (c-MWNTs) and pyrolytic carbon were used
for investigation. We found that =0.2 for arc-MWNTs (before and
after bromination treatment); = 0.1 for pyrolytic graphite;
0 for c-MWNTs. We conclude that the curvature of graphene layers
in carbon nanostructures leads to the increase of the electron-electron
interaction constant .Comment: 12 pages, 18 figures, to be published in the Proceedings of the NATO
Advanced Research Workshop on Electron Correlation in New Materials and
Nanosystems, NATO Science Series II, Springer, 200
Relationship between hyperventilation syndrome and anxiety disorders in women-internally displaced persons with threatened miscarriage
AbstractThe protracted armed conflicts create not only political, legal, socio-economic problems, form the migration flows of the population, but also affect the somatic and mental health of people. Pregnancy is a critical stage in the development of a woman's personality. According to recent studies, about 54% of women during pregnancy experience anxiety, the prevalence of hyperventilation syndrome (HVS) in population is 6-9.5%. The aim of the study was to determine the prevalence of hyperventilation syndrome and to establish its relationship with anxiety disorders in women - internally displaced persons with threatened miscarriage, living in the Luhansk region to improve treatment measures and prevent obstetric and perinatal complications. Material and Methods. The study included 35 pregnant women - IDPs who were hospitalized regarding threatened miscarriage to the hospitals, located in the Luhansk region (group I). The control group consisted of 30 pregnant women with non-complicated obstetric anamnesis and physiological course of pregnancy with similar gestational period of pregnancy and place of residence. Spielberger State-Trait Anxiety Inventory was used to assess the level of anxiety, the Nijmegen questionnaire was used to identify the manifestations of HVS. Results and discussion. Manifestations of HVS were observed in 8.57 % of patients of group I, in group II were not recorded. Patients of group I had significantly higher levels of state and trait anxiety, HVS. In group I a positive correlations between the indicators of HVS and indicators of state and trait anxiety were found. Conclusions. Antenatal study of levels of anxiety, manifestations of HVS in pregnant women - IDPs with threatened miscarriage will allow to individualize the approach to the management of pregnancy and if needed to timely develop rehabilitating measures, that will contribute to a successful outcome of the pregnancy and affect the health of the mother and her offspring.
Tests of the left-right electroweak model at linear collider
The left-right model is a gauge theory of electroweak interactions based on
the gauge symmetry SU(2)_R . The main motivations for this model are that it
gives an explanation for the parity violation of weak interactions, provides a
mechanism (see-saw) for generating neutrino masses, and has B-L as a gauge
symmetry. The quark-lepton symmetry in weak interactions is also maintained in
this theory. The model has many predictions one can directly test at a
TeV-scale linear collider. We will consider here two processes (e,e -> q, q,
barQ, barQ and e,e ->mu, nu, q, barQ) testing the lepton flavour violation
predicted by the model. We will also discuss constraints on supersymmetric
versions of the model.Comment: 22 pages, 6 figures, DESY repor
Frequency-modulation saturation spectroscopy of molecular iodine hyperfine structure near 640 nm with a diode laser source
In a frequency-modulation spectroscopy experiment, using the radiation from a
single frequency diode laser, the spectra of molecular iodine hyperfine
structure near 640 nm were recorded on the transition
. The frequency reference given by the value
of the modulation frequency (12.5 MHz in given experiment) allows determination
of the frequency differences between hyperfine components with accuracy better
than 0.1 MHz using the fitting procedure in experiment with only one laser.Comment: 3 pages, 3 figure
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