67 research outputs found
Thermal radiation and near-field energy density of thin metallic films
We study the properties of thermal radiation emitted by a thin dielectric
slab, employing the framework of macroscopic fluctuational electrodynamics.
Particular emphasis is given to the analytical construction of the required
dyadic Green's functions. Based on these, general expressions are derived for
both the system's Poynting vector, describing the intensity of propagating
radiation, and its energy density, containing contributions from
non-propagating modes which dominate the near-field regime. An extensive
discussion is then given for thin metal films. It is shown that the radiative
intensity is maximized for a certain film thickness, due to Fabry-Perot-like
multiple reflections inside the film. The dependence of the near-field energy
density on the distance from the film's surface is governed by an interplay of
several length scales, and characterized by different exponents in different
regimes. In particular, this energy density remains finite even for arbitrarily
thin films. This unexpected feature is associated with the film's low-frequency
surface plasmon polariton. Our results also serve as reference for current
near-field experiments which search for deviations from the macroscopic
approach
Shape-dependence of near-field heat transfer between a spheroidal nanoparticle and a flat surface
We study the radiative heat transfer between a spheroidal metallic
nanoparticle and a planar metallic sample for near- and far-field distances. In
particular, we investigate the shape dependence of the heat transfer in the
near-field regime. In comparison with spherical particles, the heat transfer
typically varies by factors between 1/2 and 2 when the particle is deformed
such that its volume is kept constant. These estimates help to quantify the
deviation of the actual heat transfer recorded by a near-field scanning thermal
microscope from the value provided by a dipole model which assumes a perfectly
spherical sensor
Magnetic phase diagram and transport properties of FeGe_2
We have used resistivity measurements to study the magnetic phase diagram of
the itinerant antiferromagnet FeGe_2 in the temperature range from 0.3->300 K
in magnetic fields up to 16 T. In contrast to theoretical predictions, the
incommensurate spin density wave phase is found to be stable at least up to 16
T, with an estimated critical field \mu _0H_c of ~ 30 T. We have also studied
the low temperature magnetoresistance in the [100], [110], and [001]
directions. The transverse magnetoresistance is well described by a power law
for magnetic fields above 1 T with no saturation observed at high fields. We
discuss our results in terms of the magnetic structure and the calculated
electronic bandstructure of FeGe_2. We have also observed, for the first time
in this compound, Shubnikov-de Haas oscillations in the transverse
magnetoresistance with a frequency of 190 +- 10 T for a magnetic field along
[001].Comment: 13 pages, RevTeX, 7 postscript figures, to appear in Journal of
Physics: Condensed Matte
Dissipative Van der Waals interaction between a small particle and a metal surface
We use a general theory of the fluctuating electromagnetic field to calculate
the friction force acting on a small neutral particle, e.g., a physisorbed
molecule, or a nanoscale object with arbitrary dispersive and absorptive
dielectric properties, moving near a metal surface. We consider the dependence
of the electromagnetic friction on the temperature , the separation , and
discuss the role of screening, non-local and retardation effects. We find that
for high resistivity materials, the dissipative van der Waals interaction can
be an important mechanism of vibrational energy relaxation of physisorbed
molecules, and friction for microscopic solids. Several controversial topics
related to electromagnetic dissipative shear stress is considered. The problem
of local heating of the surface by an STM tip is also briefly commented on.Comment: 11 pages, No figure
ВНУТРИПОЛОСТНАЯ ТЕРАПИЯ ОЗОНИРОВАННЫМ АНТИСЕПТИЧЕСКИМ РАСТВОРОМ В КОМПЛЕКСНОМ ЛЕЧЕНИИ ПАЦИЕНТОВ С ИНФИЦИРОВАННЫМИ ПОЛОСТНЫМИ ОБРАЗОВАНИЯМИ ПЕЧЕНИ
Application in the treatment of patients with infected cavitary formations liver intracavitary therapy ozonated antiseptic allowed significantly speed up the recovery of liver function, reduce the time of hospital treatment, to accelerate the elimination of the abscess cavity.Применение в лечении у пациентов с инфицированными полостными образованиями печени внутриполостной терапии озонированным антисептическим раствором позволило достоверно ускорить восстановление функции печени, уменьшить сроки стационарного лечения, ускорить ликвидацию полости абсцесса
ЭТИОЛОГИЧЕСКИЕ ФАКТОРЫ РАЗВИТИЯ АБСЦЕССОВ ПЕЧЕНИ
Liver abscesses of various origins are the group of severe purulent diseases of the liver and it is considered one of the difficult problems of the hepatobiliary system. The article presents the current data on the causes and microbiological composition of pathogens liver abscesses.Абсцессы печени различного генеза являются группой тяжелых гнойных заболеваний печени и считаются одной из сложных проблем гепатобилиарной системы. В статье приведены современные данные о причинах развития и микробиологическом составе возбудителей абсцессов печени
Electromagnetic field correlations near a surface with a nonlocal optical response
The coherence length of the thermal electromagnetic field near a planar
surface has a minimum value related to the nonlocal dielectric response of the
material. We perform two model calculations of the electric energy density and
the field's degree of spatial coherence. Above a polar crystal, the lattice
constant gives the minimum coherence length. It also gives the upper limit to
the near field energy density, cutting off its divergence. Near an
electron plasma described by the semiclassical Lindhard dielectric function,
the corresponding length scale is fixed by plasma screening to the Thomas-Fermi
length. The electron mean free path, however, sets a larger scale where
significant deviations from the local description are visible.Comment: 15 pages, 7 figure files (.eps), \documentclass[global]{svjour},
accepted in special issue "Optics on the Nanoscale" (Applied Physics B, eds.
V. Shalaev and F. Tr\"ager
The use of role-play as a model of teaching palliative care to interns in general medical practice
Contemporary medical higher education, especially the postgraduate training of physicians, requires a creative teaching approach to train a competent health care professional. The use of interactive role-play teaching method assists in strengthening the link between practical and theoretical skills, which is especially relevant in teaching of palliative medicine.
The paper is aimed at evaluation of the possibility of improving the effectiveness of the training of medical interns, using the role-play technique. To evaluate the impact of such interactive teaching methods as role- play in teaching of palliative care, we analyzed the effectiveness of teaching of 162 interns from 2014 to 2020. Subgroup I (n=82) involved medical interns who had in-class experience with role play technique. Subgroup II (n=80) involved interns for whom role-play teaching approach was not utilized. The findings of the analysis have revealed that the use of role-play teaching model in Subgroup I increased the academic success rate of interns to 94.7% (p≤0.05) in contrast to 81.3% (p≤0.2) in Subgroup II. Moreover, interns of Subgroup I rated the work of the teacher higher (8.2 points), compared to Subgroup II, where the score was 6.9 points. Therefore, the use of role-play as one of the interactive teaching methods in the postgraduate training of interns can improve the basic knowledge in patient care management in both theoretical and practical part of the training, which further improves professional progress and necessitates greater use of this method of interactive training in the postgraduate study
ОСОБЕННОСТИ ОСТРЫХ НАРУШЕНИЙ МОЗГОВОГО КРОВООБРАЩЕНИЯ В РОССИЙСКОЙ ФЕДЕРАЦИИ И КИТАЙСКОЙ НАРОДНОЙ РЕСПУБЛИКЕ (по данным нескольких крупных сосудистых центров)
The study focuses on comparison and analysis of the work of big stroke units in the Russian Federation and the People’s Republic of China specialized in the medical care for patients with acute stroke. 522 patients were surveyed in Russia’s and China’s regional stroke units. In the Russian Federation, patients being treated in the «City Hospital No.26» (SaintPetersburg) took part in the study. In China patients of the First Affiliated Hospital of the Chongqing Medical University, Central Hospital Jiang jin, Regional People’s Hospital Yubei district, Regional People’s Hospital Bishan (Chongqing Province). The analysis of differences was performed by the following parameters: personality traits, age, gender, level of education, income, health insurance category, profession, employment, professional activities over the last year, place of residence of the patient, features of the stroke, time during the first symptoms of stroke to hospitalization, kinds of medical services, the main risk factors and value of prevention before stroke.Исследование посвящено сравнительному анализу работы крупных сосудистых центров в Российской Федерации и Китайской Народной Республике по оказанию помощи пациентам с острым нарушением мозгового кровообращения (ОНМК). Был проведен опрос 522 пациентов в региональных сосудистых центрах РФ и КНР. В РФ в исследовании приняли участие пациенты, находящиеся на лечении в СПбГБУЗ «Городская больница № 26»; в КНР – пациенты Первой клинической больницы медицинского университета Чунцина, Центральной больницы Цзян Цзинь, Региональной народной больницы Юйбэй, Региональной народной больницы Бишань (провинция Чунцин). Был проведен анализ различий по следующим показателям: личностные факторы пациента, возраст, пол, уровень образования, уровень дохода, вид медицинского страхования, профессия, занятость, профессиональная деятельность в течение последнего года, место жительства пациента, особенности заболевания, время с момента появления первых симптомов до госпитализации, спектр оказываемых медицинских услуг, основные факторы риска и объем профилактики инсульта до заболевания
Van der Waals-Casimir-Polder interaction of an atom with a composite surface
We study the dispersion interaction of the van der Waals and Casimir-Polder
(vdW-CP) type between a neutral atom and the surface of a metal by allowing for
nonlocal electrodynamics, i.e. electron diffusion. We consider two models: (i)
bulk diffusion, and (ii) diffusion in a surface charge layer. In both cases the
transition to a semiconductor is continuous as a function of the conductivity,
unlike the case of a local model. The relevant parameter is the electric
screening length and depends on the carrier diffusion constant. We find that
for distances comparable to the screening length, vdW-CP data can distinguish
between bulk and surface diffusion, hence it can be a sensitive probe for
surface states.Comment: v2: expanded references, statements on current status in the field.
10 pages, 6 figure
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