نتایج جستجو برای: hf wave
تعداد نتایج: 238190 فیلتر نتایج به سال:
Hartree-Fock (HF) method is a useful first-step tool for investigating electronic structure and total energy of atoms and molecules: it gives very good electron density, reasonably accurate total energy, and molecular orbitals and orbital energies that are helpful for understanding the electronic structure. The HF method is, however, not commonly applied to solids nowadays, since electronic scr...
Radio waves provide a useful diagnostic tool to investigate the properties of ionosphere because affects transmission and High Frequency (HF) electromagnetic waves. We have conducted transionospheric HF-propagation research campaign with nanosatellite on low-Earth polar orbit EISCAT HF transmitter facility in Troms{\o}, Norway, December 2020. In active measurement, transmitted sinusoidal 7.953 ...
BACKGROUND Current electrocardiographic and echocardiographic measurements in heart failure (HF) do not take into account the complex interplay between electrical activation and local wall motion. The utilization of novel technologies to better characterize cardiac electromechanical behavior may lead to improved response rates with cardiac resynchronization therapy (CRT). Electromechanical wave...
[1] ELF/VLF radio waves (300 Hz to 30 kHz) have been successfully generated via modulated HF (3–10 MHz) heating of the lower ionosphere in the presence of natural currents, most recently with the HAARP facility in Alaska. Generation is possible via amplitude modulation or via two techniques involving motion of the HF beam during the ELF/VLF cycle, known as beam painting and geometric modulation...
BACKGROUND Central arterial stiffness has been shown to play a key role in cardiovascular disease. However, evidence regarding such arterial stiffness from various arterial segments in relation to B-type natriuretic peptide (BNP) remains elusive. METHODS A total of 1255 participants (47.8% men; mean age: 62.6 ± 12.3 [SD] years) with preserved left ventricular function (ejection fraction ≥50%)...
[1] It is well established that Extremely Low Frequency (ELF, 0.3–3 kHz) and Very Low Frequency (VLF, 3–30 kHz) radio waves can be generated via modulated High Frequency (HF, 3–10 MHz) heating of the lower ionosphere (60–100 km). The ionospheric absorption of HF power modifies the conductivity of the lower ionosphere, which in the presence of natural currents such as the auroral electrojet, cre...
AIMS The detection of non-ischaemic (mainly hypertension, diabetes, and obesity) stage B heart failure (SBHF) may facilitate the recognition of those at risk of progression to overt HF and HF prevention. We sought the relationship of specific electrocardiographic (ECG) markers of SBHF to echocardiographic features of SBHF and their prognostic value for development of HF. The ECG markers were Co...
Two fundamental facts of the modern wave turbulence theory are 1) existence of power energy spectra in k-space, and 2) existence of “gaps” in this spectra corresponding to the resonance clustering. Accordingly, three wave turbulent regimes are singled out: kinetic, described by wave kinetic equations and power energy spectra; discrete, characterized by resonance clustering; and mesoscopic, wher...
INTRODUCTION AND OBJECTIVES To evaluate the clinical characteristics and prognosis of heart failure (HF) development in patients hospitalized for acute myocardial infarction (AMI). PATIENTS AND METHOD Between May 1990 and March 2000, 836 consecutive patients were admitted with a diagnosis of AMI within 24 h of symptom onset. HF was defined as the presence of rales and a third heart sound with...
AIMS Although left ventricular (LV) relaxation is well recognized as a predictor of mitral annulus (MA) early diastolic (E') velocity, its significance relative to other predictors of E' is less well understood. METHODS AND RESULTS We assessed 40 healthy volunteers, 43 patients with acutely decompensated chronic systolic heart failure (HF), and 36 patients with hypertrophic obstructive cardio...
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