317 research outputs found
Dromion perturbation for the Davey-Stewartson-1 equations
The perturbation of the dromion of the Davey-Stewartson-1 equation is studied
over the large time
Lanthanum-Gallium Tantalate Crystals and their Electrophysical Characterization
Lanthanum-gallium tantalate single crystal (La3Ta0.5Ga5.5O14, langatate, LGT) is a perspective piezoe-lectric material as an active component of pressure sensors. An investigation of the growth conditions in-fluence (the growth atmosphere) on the electrophysical сharacterization of LGT, obtained in different at-mospheres (Ar, Ar + O2) was carried out. The frequency dependences of the relative dielectric constant
(ε11/ε0) and of the admittance depend on the growth atmosphere. The langatate electrophysical сharacteri-zation in alternating electric fields were analyzed by means of the impedance spectr oscopy method. The
behavior of short circuit currents in specimens of polar cuts of LGT single crystals with the same material
electrodes without preliminary polarization is described.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3628
Comparison of dynamic of autonomic control indices in cardiovascular system under the treatment by ACE inhibitor (Enalapril) and beta-blocker (Metoprolol) in patients with hypertension
The objective of the present research was to compare the influence of Enalapril and Metoprolol on synchronization of 0.1 Hz-regulation of heart and blood microcirculation. 42 patients aged 49±9 years old with hypertension I, II were included in the study. 0.1 Hz-oscillations in heart rate variability (HRV) and blood microcirculation were registered during the passive orthostatic sign while breathing spontaneously. The duration of each test was 10 minutes. Synchronization was estimated as a phase difference between 0.1 Hz-rhythms in heart rate and in filling of blood microcirculation. Quantitative measures of synchronization were also estimated. In addition frequency values of HRV spectrum in LF- and HF-ranges were assessed. Enalapril and Metoprolol had comparable effect on blood pressure reduction. Treatment with both Enalapril and Metoprolol in patients with significant vegetative dysfunction resulted in repair of functional interaction between 0.1 Hz-regulation of heart and blood microcirculation. Enalapril was preferred in hypertensive patients with prevalence of disorders of vegetative regulation of blood microcirculation. Metoprolol influenced positively on 0,1 Hz-rhythm synchronization in patients with predominance of heart vegetative regulation dysfunction and in patients with sympathicotonia. In patients with hypertension and initially normal level of synchronization of 0.1 Hz-mechanisms treatment with Enalapril or Metoprolol caused functional dissociation. Differentiated approach to the choice of hypertensive therapy should consider individual peculiarities of system vegetative dysfunction. The level of synchronization of 0.1 Hz-rhythms in cardiovascular system should especially be evaluated initially and during the treatmen
Piezoelectric Characteristics of LiNbO3 Thin-film Heterostructures via Piezoresponse Force Microscopy
Electro-optic LiNbO3 thin films were deposited on Si(100) and Si(111) substrates using a radio-frequency magnetron sputtering process. The piezoelectric properties of the LiNbO3 films were investigated using the scanning probe microscopy in the piezoresponse mode. The obtained results show the high degree of grains orientation in polycrystalline structure. The piezoelectric modulus (dzz) was estimated to be 16 pm/V (for LiNbO3 / Si(100)) and 22 pm/V (for LiNbO3 / Si(111)) and the polarization about of 0.37 C·m – 2. These values are larger than those reported previously for LiNbO3 films.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3366
Formation of the Electric Field Distribution in Thin Electro-Optic Layers for Precision Correction their Optical Characteristics
A method of making given field distribution within thin electro-optical layers by using narrow band electrodes placed at the same electric potential. A formula for electric field intensity produced by a single band electrode is obtained. Electric field modeling for different band electrode configurations is undertaken. It was shown, by applying piezoresponse force microscopy, that in case of highly inhomogeneous field the polarization of lithium niobate electro-optical film persisted only in the area above
the band electrode.
Lithium niobate, electro-optical structures, piezoresponse force microscopy, Computer
simulation
Comparative evaluation of autonomic regulation of circulation in patients undergone coronary artery bypass grafting or correction of acquired valvular heart disease
The aim of the research was to study the peculiarities of vegetative regulation of blood circulation in cardiac surgery patients who underwent coronary artery bypass grafting (CABG) or correction of acquired valvular heart disease (CAVHD). Material and Methods. In this study we included 42 patients (12 women; 63 (57; 67) years), who underwent CABG, and 36 patients (16 women; 58 (47; 65) years) who underwent CAVHD. The synchronous 15 minutes records of electrocardiogram and photoplethysmogram (PPG) were performed in all patients before and after surgery. Time domain and frequency domain measures of heart rate variability (HRV) and index of synchronization between low-frequency (LF) oscillations in HRV and PPG (index S) were analyzed. Results. Most studied autonomic indices did not have statistically significant differences between patients with CABG and CAVHD in the study stages, except for heart rate, which was higher in patients before CAVHD (p=0,013). Conclusion. The values of HRV and index S do not depend on the difference in the clinical status and the features of performed cardiac surgical interventions between patients with CABG and CAVHD.</p
ПРОФИЛАКТИКА ТУБЕРКУЛЕЗА: СОВРЕМЕННЫЕ ПОДХОДЫ К РАЗРАБОТКЕ ПРОТИВОТУБЕРКУЛЕЗНЫХ ВАКЦИН
This review is focused on recent advances in development of new vaccines for the prevention of tuberculosis. The main reasons for lack of BCG vaccine efficacy in different populations and geographic regions are presented. Design of new vaccines based on live modified strains of Mycobacterium bovis BCG, attenuated strains of Mycobacterium tuberculosis, recombinant proteins and viral vectors is considered in the specific examples. The usage of the heterologous «prime-boost» vaccination strategy against tuberculosis is discussed. В обзоре освещены современные достижения в области разработки новых вакцин для профилактики туберкулеза. Представлены основные причины недостаточной эффективности вакцины БЦЖ в различных популяциях и географических регионах. На конкретных примерах рассмотрены направления дизайна новых вакцин на основе живых модифицированных штаммов Mycobacterium bovis БЦЖ, аттенуированных штаммов Mycobacterium tuberculosis, рекомбинантных белков и вирусных векторов. Обсуждается перспектива применения схемы гетерологичной «prime-boost» вакцинации против туберкулеза.
SU(3) Predictions for Weak Decays of Doubly Heavy Baryons -- including SU(3) breaking terms
We find expressions for the weak decay amplitudes of baryons containing two b
quarks (or one b and one c quark -- many relationship are the same) in terms of
unknown reduced matrix elements. This project was originally motivated by the
request of the FNAL Run II b Physics Workshop organizers for a guide to
experimentalists in their search for as yet unobserved hadrons. We include an
analysis of linear SU(3) breaking terms in addition to relationships generated
by unbroken SU(3) symmetry, and relate these to expressions in terms of the
complete set of possible reduced matrix elements.Comment: 49 page
Synthesis and Nanoscale Characterization of LiNbO3 Thin Films Deposited on Al2O3 Substrate by RF Magnetron Sputtering under Electric Field
LiNbO3 thin films were deposited on Al2O3 substrates by RF-magnetron sputtering with in-situ electric
field to study the self-polarization effect. The films have been characterized crystallographically by x-ray
diffraction, and morphologically by atomic force microscopy. The films contain crystallites of LiNbO3 with
preferable orientation [012] along the normal to the Al2O3 substrate surface (012). Piezoresponse force
microscopy was used to study vertical and lateral polarization direction in LiNbO3 thin films. The analysis
of the histograms of vertical piezoresponse images allowed to reveal self-polarization effect in films. The
local piezoelectric hysteresis performed on the nanometer scale indicates switching behavior of polarization
for LiNbO3 thin film
High statistic measurement of the K- -> pi0 e- nu decay form-factors
The decay K- -> pi0 e- nu is studied using in-flight decays detected with the
ISTRA+ spectrometer. About 920K events are collected for the analysis. The
lambda+ slope parameter of the decay form-factor f+(t) in the linear
approximation (average slope) is measured: lambda+(lin)= 0.02774 +-
0.00047(stat) +- 0.00032(syst). The quadratic contribution to the form-factor
was estimated to be lambda'+ = 0.00084 +- 0.00027(stat) +- 0.00031(syst). The
linear slope, which has a meaning of df+(t)/dt|_{t=0} for this fit, is lambda+
= 0.02324 +- 0.00152(stat) +- 0.00032(syst). The limits on possible tensor and
scalar couplings are derived: f_{T}/f_{+}(0)=-0.012 +- 0.021(stat) +-
0.011$(syst), f_{S}/f_{+}(0)=-0.0037^{+0.0066}_{-0.0056}(stat) +- 0.0041(syst).Comment: 11 pages, 8 figures. Accepted by Phys.Lett.
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