145 research outputs found

    Low-frequency magnetic sensing by magnetoelectric metglas/bidomain LiNbO3 long bars

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    We present an investigation into the magnetic sensing performance of magnetoelectric bilayered metglas / bidomain LiNbO3 long thin bars operating in a cantilever or free vibrating regime and under quasi-static and low-frequency resonant conditions. Bidomain single crystals of Y+128o-cut LiNbO3 were engineered by an improved diffusion annealing technique with a polarization macrodomain structure of the “head-to-head” and “tail-to-tail” type. Long composite bars with lengths of 30, 40 and 45 mm, as well as with and without attached small tip proof masses, were studied. ME coefficients as large as 550 V/cm∙Oe, corresponding to a conversion ratio of 27.5 V/Oe, were obtained under resonance conditions at frequencies of the order of 100 Hz in magnetic bias fields as low as 2 Oe. Equivalent magnetic noise spectral densities down to 120 pT/Hz1/2 at 10 Hz and to 68 pT/Hz1/2 at a resonance frequency as low as 81 Hz were obtained for the 45 mm long cantilever bar with a tip proof mass of 1.2 g. In the same composite without any added mass the magnetic noise was shown to be as low as 37 pT/Hz1/2 at a resonance frequency of 244 Hz and 1.2 pT/Hz1/2 at 1335 Hz in a fixed cantilever and free vibrating regimes, respectively. A simple unidimensional dynamic model predicted the possibility to drop the low-frequency magnetic noise by more than one order of magnitude in case all the extrinsic noise sources are suppressed, especially those related to external vibrations, and the thickness ratio of the magnetic-to-piezoelectric phases is optimized. Thus, we have shown that such systems might find use in simple and sensitive room-temperature low-frequency magnetic sensors, e.g., for biomedical applications.publishe

    Magnetoelectric metglas/bidomain y + 140°-cut lithium niobate composite for sensing fT magnetic fields

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    We investigated the magnetoelectric properties of a new laminate composite material based on y+140°-cut congruent lithium niobate piezoelectric plates with an antiparallel polarized “head-to-head” bidomain structure and metglas used as a magnetostrictive layer. A series of bidomain lithium niobate crystals were prepared by annealing under conditions of Li2O outdiffusion from LiNbO3 with a resultant growth of an inversion domain. The measured quasi-static magnetoelectric coupling coefficient achieved |αE31| = 1.9 V·(cm·Oe)–1. At a bending resonance frequency of 6862 Hz, we found a giant |αE31| value up to 1704 V·(cm·Oe)–1. Furthermore, the equivalent magnetic noise spectral density of the investigated composite material was only 92 fT/Hz1/2, a record value for such a low operation frequency. The magnetic-field detection limit of the laminated composite was found to be as low as 200 fT in direct measurements without any additional shielding from external noises.publishe

    The ηgg\eta^\prime g^* g^* vertex with arbitrary gluon virtualities in the perturbative QCD hard scattering approach

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    We study the ηgg\eta^\prime g^* g^* vertex for arbitrary gluon virtualities in the time-like and space-like regions, using the perturbative QCD hard scattering approach and an input wave-function of the η\eta^\prime-meson consistent with the measured ηγγ\eta^\prime \gamma^* \gamma transition form factor. The contribution of the gluonic content of the η\eta^\prime-meson is taken into account, enhancing the form factor over the entire virtuality considered. However, data on the electromagnetic transition form factor of the η\eta^\prime-meson is not sufficient to quantify the gluonic enhancement. We also study the effect of the transverse momenta of the partons in the η\eta^\prime-meson on the ηgg\eta^\prime g^* g^* vertex, using the modified hard scattering approach based on Sudakov formalism. Analytic expressions for the ηgg\eta^\prime g^* g^* vertex are presented in limiting kinematic regions and parametrizations are given satisfying the QCD anomaly, for real gluons, and perturbative QCD behavior for large gluon virtualities, in both the time-like and space-like regions. Our results have implications for the inclusive decay BηXB \to \eta^\prime X and exclusive decays, such as Bη(K,K)B \to \eta^\prime (K,K^*), and in hadronic production processes N+N(Nˉ)ηXN + N (\bar N) \to \eta^\prime X.Comment: 23 pages, 19 figures (requires revtex4, amssymb, epsf); several typos corrected, this version now identical to the one accepted for publication in Phys. Rev.

    СТРУКТУРНЫЕ ОСОБЕННОСТИ КОСТНОЙ ТКАНИ ПРИ КОКСАРТРОЗЕ, ВЫЯВЛЕННЫЕ МЕТОДОМ СПЕКТРОСКОПИИ КОМБИНАЦИОННОГО РАССЕЯНИЯ СВЕТА

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    The structure of human bone slices taken from patients suffering from deforming arthrosis of the hip joint (coxarthrosis) was studied by Raman spectroscopy. Comparative analysis of healthy and sick bone tissues was made on the basis of the intensity ratio of RS bands associated with organic and mineral components. It was shown that coxarthrosis results in a relative increase of an organic component and in a higher degree of substitution of phosphate groups by carbonate ones in the hydroxyapatite lattice. Методом спектроскопии комбинационного рассеяния света исследована структура срезов костной ткани людей, страдающих деформирующим артрозом тазобедренного сустава (коксартроз). Проведен сравнительный анализ срезов здоровых и больных участков костной ткани по соотношению интенсивностей полос комбинационного рассеяния, характеризующих долю органической и минеральной фазы. Показано, что для разрушенной в результате коксартроза костной ткани характерна более высокая доля органической составляющей и более высокая степень замещения фосфатной группы на карбонатную в решетке гидроксиапатита.

    Формирование фотоприемных структур ИК-диапазона путем пересыщения кремния теллуром

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    The Si layers doped with Te up to the concentrations of (3–5)1020 cm–3 have been formed via ion implantation and pulsed laser melting. It is found, 70–90 % of the embedded impurity atoms are in substitution states in the silicon lattice. These layers have revealed significant absorption (35–66 %) in the wavelength λ range of 1100–2500 nm. In this case, the absorption coefficient increases with the λ growth. The absorption spectra of the implanted layers after pulsed laser melting, equilibrium furnace annealing, and rapid thermal annealing have been compared. It is shown that equilibrium furnace annealing increases the photon absorption by 4 % in the wavelength range of 1100–2500 nm in comparison with virgin Si. After rapid thermal annealing, the photon absorption in the IR-range increases only by 2 %.Слои кремния, легированные теллуром до концентраций (3–5)1020 см–3, получены ионной имплантацией с последующим импульсным лазерным отжигом. Показано, что 70–90 % внедренной примеси находится в позиции замещения в решетке кремния. Слои, гиперпересыщенные теллуром, проявляют существенное поглощение (35–66 %) в области длин волн 1100–2500 нм, причем коэффициент поглощения увеличивается с ростом длины волны. Проведено сравнение спектров поглощения имплантированных слоев после лазерного отжига, а также после равновесного и быстрого термического отжигов. Показано, что равновесный отжиг после имплантации ионов теллура увеличивает поглощение фотонов в области длин волн 1100–2500 нм на 4 % по сравнению с неимплантированным кремнием. После быстрого термического отжига поглощение в ИК-области возрастает лишь на 2 %

    2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death the Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC) Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC)

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    Modeling linkage disequilibrium increases accuracy of polygenic risk scores

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    ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: executive summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients With Atrial Fibrillation)

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    Atrial fibrillation (AF), the most common sustained cardiac rhythm disturbance, is increasing in prevalence as the population ages. Although it is often associated with heart disease, AF occurs in many patients with no detectable disease. Hemodynamic impairment and thromboembolic events result in significant morbidity, mortality, and cost. Accordingly, the American College of Cardiology (ACC), the American Heart Association (AHA), and the European Society of Cardiology (ESC) created a committee of experts to establish guidelines for management of this arrhythmia

    ACC/AHA/ESC guidelines for the management of patients with atrial fibrillation: Executive summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines and Policy Conferences (Committee to Develop Guidelines for the Management of Patients with Atrial Fibrillation)

    Get PDF
    Atrial fibrillation (AF), the most common sustained cardiac rhythm disturbance, is increasing in prevalence as the population ages. Although it is often associated with heart disease, AF occurs in many patients with no detectable disease. Hemodynamic impairment and thromboembolic events result in significant morbidity, mortality, and cost. Accordingly, the American College of Cardiology (ACC), the American Heart Association (AHA), and the European Society of Cardiology (ESC) created a committee of experts to establish guidelines for management of this arrhythmia
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