436 research outputs found
Coating synthesis controlled by electron-beam heating
The methods of combined electron-beam treatment of parts made of steel with one- and two-layer coatings are studied experimentally. Ti-Ni, Ni-Al and Al-Ti systems were used as the examples in the experiments. The mathematical model is suggested for coating formation in the controlled regime of high temperature synthesis during high energy source motion along the preliminarily deposited layer of exothermic composition. The study takes into account the difference in thermophysical properties of the materials of coating and substrate, heat release from chemical reaction that leads to the coating properties formation and other factors. The realization of the synthesis depends on technological parameters. Various regimes of the treatment process are investigated numerically
ФЕНОМЕН ГЛОБАЛЬНОГО МІСТА: ПРОБЛЕМИ ПОШУКУ ІДЕНТИЧНОСТІ В СУЧАСНОМУ МУЛЬТИКУЛЬТУРНОМУ ПРОСТОРІ (’Global City’ Phenomenon: Search for Identity Problems in Multicultural Space )
У статті висвітлюються основні аспекти соціокультурного
виміру
поняття
«глобальне
місто».
Аналізуються
проблеми
пошуку
національної
та
етнічної
ідентичності
в
мультикультурному
просторі
глобального
міста.
Узагальнюються
основні
чинники
стосовно
проблеми
пошуку
ідентичності
в контексті сучасних викликів політиці мультикультуралізму (The article deals with the main principles of the sociocultural
dimension of «global city.» The authors analyze the problems of
national and ethnic identity searching in a multicultural global
city space. Paper sums up the problems of identity factor in the
context of the modern challenges of multicultural politics
Scalings for ultra-relativistic laser plasmas and monoenergetic electrons
The similarity theory is derived for ultra-relativistic laser-plasma
interactions. First, it is shown that the most fundamental S-similarity is
valid for both under- and overdense plasmas. Then, the particular case of
tenious plasma is considered in great detail. It is shown that the electron
dynamics in this case has two characteristic scales. The fast scale corresponds
to relaxation to some attractor solution. The slow dynamics describes an
adiabatic evolution of this attractor. This leads to a remarkable wave breaking
exclusion rule in the 3D geometry. A similarity theory for the slow dynamics
allows obtaining simple ``engineering'' scalings for the maximum electron
energies, the number of accelerated electrons, the electron beam density, and
for the acceleration distance. These scalings are aimed at design of a
high-energy laser-plasma accelerator generating electron beams with superior
properties
Relativistic Doppler effect: universal spectra and zeptosecond pulses
We report on a numerical observation of the train of zeptosecond pulses
produced by reflection of a relativistically intense femtosecond laser pulse
from the oscillating boundary of an overdense plasma because of the Doppler
effect. These pulses promise to become a unique experimental and technological
tool since their length is of the order of the Bohr radius and the intensity is
extremely high W/cm. We present the physical mechanism,
analytical theory, and direct particle-in-cell simulations. We show that the
harmonic spectrum is universal: the intensity of th harmonic scales as
for , where is the largest --factor
of the electron fluid boundary, and for the broadband and
quasimonochromatic laser pulses respectively.Comment: 4 figure
The bone panaris in children
The most widespread festering-inflammatory disease of brush is a panaris. Panaris — an acute purulent inflammation of the finger tissue. Forms panaris, accompanied by lesions of bone , the most difficult to treatment. Analyzed the case histories of 64 children hospitalized in the Department of purulent surgery DGKB № 9 for 2017-2019 with clinical bone panaris. In the study, disease duration before resorting to the surgeon was on average 5.8 days. 37.5% of patients were self-treatment. Outpatient treatment by a surgeon in the community was conducted in 32.8% of cases. In the analysis of anamnestic data in 14 children developed a bone panaris finger after trauma. In most cases, damaged distal phalanx of the second finger of the left and right hand. All patients complained of pain in the finger, swelling, local hyperemia of the skin. The clinical picture of bone panaris dominated local changes. The x-ray revealed the heterogeneity of the bone structure in 4 patients, the violation of the integrity of the cortical layer in 1 child, marginal bone destruction phalanx in 43 children, sequestration of the nail phalanx in 3 patients, no changes were detected in 13 patients. Treatment of bone panaris surgery. In the complex post-operative care included: anti-bacterial, antihistamines, preparation that improve blood rheology and local treatment with antiseptic bandage, physiotherapy. Diagnosis of bone panaris based on clinical and radiological data. The main method of treatment is surgicalСамым распространенным гнойно-воспалительным заболеванием кисти является панариций. Панариций — острое гнойное воспаление тканей пальца. Формы панариция, сопровождающиеся поражениями костей, наиболее сложны для лечения. Проанализированы истории болезни 64 детей, госпитализированных в отделение гнойной хирургии ДГКБ № 9 за 2017-2019 годы с клиническим панарицием кости. В исследовании продолжительность заболевания до обращения к хирургу составила в среднем 5,8 дня. 37,5% пациентов прошли самолечение. Амбулаторное ле- чение хирургом по месту жительства проводилось в 32,8% случаев. При анализе анамнестических данных у 14 детей развитие костного панариция произошло после травмы. В большинстве случаев повреждена дистальная фаланга второго пальца левой и правой кисти. Все больные предъявляли жалобы на боли в пальце, отеки, локальную гиперемию кожи. В клинической картине костного панариция преобладали местные изменения. Рентген выявил неоднородность структуры кости у 4 пациентов, нарушение целостности кортикального слоя у 1 ребенка, разрушение краевой фаланги кости у 43 детей, секвестрация фаланги ногтя у 3 пациентов, изменений не выявлено у 13 пациентов. Лечение костного панариция хирургическое. В комплекс послеоперационного ухода входят: антибактериальные, антигистаминные препараты, препараты, улучшающие реологию крови, и местное лечение антисептическими повязками, физиотерапия. Диагностика костного панариция основана на клинических и рентгенологических данных. Основным методом лечения является хирургически
Theory of high harmonic generation in relativistic laser interaction with overdense plasma
High harmonic generation due to the interaction of a short ultra relativistic
laser pulse with overdense plasma is studied analytically and numerically. On
the basis of the ultra relativistic similarity theory we show that the high
harmonic spectrum is universal, i.e. it does not depend on the interaction
details. The spectrum includes the power law part for
, followed by exponential decay. Here
is the largest relativistic -factor of the plasma
surface and is the second derivative of the surface velocity at this
moment. The high harmonic cutoff at is parametrically
larger than the predicted by the ``oscillating mirror''
model based on the Doppler effect. The cornerstone of our theory is the new
physical phenomenon: spikes in the relativistic -factor of the plasma
surface. These spikes define the high harmonic spectrum and lead to attosecond
pulses in the reflected radiation.Comment: 12 pages, 9 figure
Training in cooperation with the use of information technology
Training of modern graduate takes place in the conditions of requirements of the Federal state educational standards aimed at development of students’ competences. In order to train a competent graduate, higher education institutions are looking for ways that will make this process more effective and dynamic. The purpose of the article is to analyze the experience of higher education institutions in the implementation of training in cooperation with the use of information technology. The wide development of information technologies and their penetration into various spheres of society has determined their implementation in the educational process. The use of information technology is based on the use of personal computers. Now this tool is an integral part of the modern educational process. Placing emphasis on the fact that learning in cooperation is not a fundamentally new technology the authors say that it acquires relevance by incorporating innovative technologies. The article considers the ideas of training in cooperation with the use of information technologies, raises the importance and significance of this issue in modern educational conditions. Training in cooperation expands the students' information field. On the basis of the study of scientific literature, the features of training in cooperation, its essence and value purpose for the formation of competence of students of pedagogical University are highlighted. The study suggests an increase in students ' motivation to study materials after the introduction of information technologies that allow them to be more mobile and creative. The process of mutual learning in the process of cooperation becomes more effective. The higher the motivation of the student to study the discipline is, the higher the level of his knowledge is. The results of the study can be used in the further implementation of information technologies for the development of the learning process in cooperation
Ground Beetles (Coleoptera, Carabidae) Assemblages Features Formation in Large and Medium Industrial Cities of Russia (The Case Study in Kazan, Kemerovo and Grozny)
The article presents the results of the analysis of the Carabid fauna of three cities: Grozny, Kemerovo, Kazan. It was established that communities of ground beetles clearly respond to varying degrees of recreation by changing the biotopic distribution and ecological structure: the emergence of super dominant species, a decrease in the abundance of zoophages, an increase in the share of stratobionts, and the presence of indicator species
Surgical tactics in soft tissues defects of the nail phalanges of the fingers in children
The purpose of the study is to analyze the options for surgical tactics depending on the type and severity of the injury, and to evaluate the results of surgical treatment.Цель исследования – Изучить структуру повреждений мягких тканей ногтевых фаланг пальцев кисти у детей, проанализировать варианты хирургической тактики в зависимости от вида и тяжести травмы, оценить результаты оперативного лечения
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