8 research outputs found
The case of a large left atrial myxoma complicated by a cardioembolic cerebral infarction
With the advent of echocardiography significantly increased frequency of in vivo diagnosis of cardiac myxomas. Needs awareness of cardiologists and experts of related specialties regarding the polymorphism of clinical manifestations, morphology, complications and other features of cardiac myxomas is the key to early diagnosis and successful treatment, because it is one of the few potentially curable tumors of the heart. Although a myxoma of the heart belongs among the most studied tumors, ongoing research on etiology, morphology, histogenesis mix, and given us a clinical case indicate the need for improved knowledge about mixomas in order to improve the diagnosis and treatment of patients with cardiac tumors.С появлением эхокардиографии существенно увеличилась частота прижизненной диагностики миксом сердца. Должная осведомленность кардиологов и специалистов смежных специальностей касательно полиморфизма клинических проявлений, морфологии, осложнений и других характеристик миксомы сердца является залогом ранней диагностики и успешного лечения, поскольку это одна из немногих потенциально излечимых опухолей сердца. Хотя миксома сердца принадлежит к наиболее изученным опухолям, продолжающиеся исследования в области этиологии, морфологии, гистогенеза миксом, а также приведенный нами клинический случай указывают на необходимость совершенствования знаний о миксомах в целях улучшения диагностики и лечения пациентов с опухолями сердца
ANALYSIS OF PULSED FIELDS REFLECTED FROM A LAYERED LOSSY MEDIUM USING ARTIFICIAL NEURAL NETWORK
MICROWAVE ELECTRODYNAMICSRadiation of Short Pulses from the Open End of a Circular Waveguide
Near field of Hertzian dipole excited by impulse current
The angle dependence of near field radiated of Hertzian dipole excited by transient current is investigated. The more precise approximation in the solution for near field of the dipole is obtained in time domain by means of vector potential technique. As an example, the quickly decreasing excitation current case is considered
Analysis of fields reflected from model of human body surface using artificial neural network in time domain
The problem of determination of thickness a layer of layered medium by impulse irradiation is considered. The impulse fields reflected from the model of human body surface are analyzed by artificial neural network in time domain directly. The normal incidence of plane wave with Gaussian time form on the layered medium with losses is considered. The reflected electromagnetic field is obtained by FDTD method. Initial data for neural network analysis are the values of amplitude of electrical component of reflected field. As an example, the network is trained to determine the thickness of one of the layers of the medium. The stability of the determination in presence of interferences, experimental errors and instabilities of medium parameters is investigated by numerical simulation
Transient radiation from the open end of circular waveguide
The transient radiation from the open end of a circular waveguide is considered by simple analytical and direct numerical methods. The radiation of short pulse from the aperture is provided by calculation of special time form of field by means of modal basis method that permits to solve the problem of pulse evolution for positive and negative time with the use of Laplace transform. The radiation of the short pulse is calculated in Kirchhoff approximation and simulated by FDTD method. The frequency characteristics of the radiated field are considered