779 research outputs found
Edge Channel Interference Controlled by Landau Level Filling
We study the visibility of Aharonov-Bohm interference in an electronic
Mach-Zehnder interferometer (MZI) in the integer quantum Hall regime. The
visibility is controlled by the filling factor and is observed only
between and 1.0, with an unexpected maximum near .
Three energy scales extracted from the temperature and voltage dependences of
the visibility change in a very similar way with the filling factor, indicating
that the different aspects of the interference depend sensitively on the local
structure of the compressible and incompressible strips forming the quantum
Hall edge channels.Comment: 5 pages, 5 figures, final version accepted for publication in Phys.
Rev.
Counting Statistics and Dephasing Transition in an Electronic Mach-Zehnder Interferometer
It was recently suggested that a novel type of phase transition may occur in
the visibility of electronic Mach-Zehnder Interferometers. Here, we present
experimental evidence for the existence of this transition. The transition is
induced by strongly non-Gaussian noise that originates from the strong coupling
of a quantum point contact to the interferometer. We provide a transparent
physical picture of the effect, by exploiting a close analogy to the
neutrino-oscillations of particle physics. In addition, our experiment
constitutes a probe of the singularity of the elusive full counting statistics
of a quantum point contact.Comment: 7 pages, 4 figures (+Supplement 8 pages, 9 figures
The Effect of High Background and Dead Time of an InGaAs/InP Single-Photon Avalanche Photodiode on the Registration of Microsecond Range Near-Infrared Luminescence
The effects of a high background count and a microsecond dead time interval on a gated InGaAs/InP single-photon avalanche photodiode (SPAD) during microsecond luminescence decay registration are discussed. It is shown that the background count rate of the SPAD limits its use for time-resolved and steady-spectral measurements, and that a “pile-up” effect appears in the microsecond range
Detailed Classification of Swift's Gamma-Ray Bursts
Earlier classification analyses found three types of gamma-ray bursts (short,
long and intermediate in duration) in the BATSE sample. Recent works have shown
that these three groups are also present in the RHESSI and the BeppoSAX
databases. The duration distribution analysis of the bursts observed by the
Swift satellite also favors the three-component model. In this paper, we extend
the analysis of the Swift data with spectral information. We show, using the
spectral hardness and the duration simultaneously, that the maximum likelihood
method favors the three-component against the two-component model. The
likelihood also shows that a fourth component is not needed.Comment: Accepted for publication in The Astrophysical Journa
Beyond Charge Transfer: The impact of auger recombination and FRET on PL quenching in an rGO-QDs system
PL intensity quenching and the PL lifetime reduction of fluorophores located close to gra‐ phene derivatives are generally explained by charge and energy transfer processes. Analyzing the PL from PbS QDs in rGO/QD systems, we observed a substantial reduction in average PL lifetimes with an increase in rGO content that cannot be interpreted solely by these two processes. To explain the PL lifetime dependence on the rGO/QD component ratio, we propose a model based on the Auger recombination of excitations involving excess holes left in the QDs after the charge transfer process. To validate the model, we conducted additional experiments involving the external engi‐ neering of free charge carriers, which confirmed the role of excess holes as the main QD PL quench‐ ing source. A mathematical simulation of the model demonstrated that the energy transfer between neighboring QDs must also be considered to explain the experimental data carefully. Together, Au‐ ger recombination and energy transfer simulation offers us an excellent fit for the average PL life‐ time dependence on the component ratio of the rGO/QD system
Installation for service passenger cars brake system
Рассмотрена важность тормозной системы, а именно тормозных жидкостей для легковых автомобилей, предоставлена установка с помощью которой заправляют, прокачивают тормозную систему автомобилей, для облегчения работы на станциях технического обслуживания.Considered the importance of the braking system, namely, brake fluids for passenger cars, provided installation through which run the show pumped brake systems, to facilitate the work at service stations
Complex magnetic ordering in the oxide selenide Sr2Fe3Se2O3
Sr2Fe3Se2O3 is a localised-moment iron oxide selenide in which two unusual coordinations for Fe2+
ions form two sublattices in a 2:1 ratio. In the paramagnetic region at room temperature the
compound adopts the crystal structure first reported for Sr2Co3S2O3, crystallising in space group
Pbam with a = 7.8121 Å, b = 10.2375 Å, c = 3.9939 Å and Z = 2. The sublattice occupied by two thirds
of the iron ions (Fe2 site) is formed by a network of distorted mer-[FeSe3O3] octahedra linked via
shared Se2 edges and O vertices forming layers, which connect to other layers by shared Se vertices.
As shown by magnetometry, neutron powder diffraction and Mössbauer spectroscopy
measurements, these moments undergo long range magnetic ordering below TN1 = 118 K, initially
adopting a magnetic structure with a propagation vector (½–δ, 0, ½) (0 ≤ ≤ 0.1) which is
incommensurate with the nuclear structure and described in the Pbam1’(a01/2)000s magnetic
superspace group, until at 92 K (TINC) there is a first order lock-in transition to a structure in which
these Fe2 moments form a magnetic structure with a propagation vector (½ , 0, ½) which may be
modelled using a 2a × b × 2c expansion of the nuclear cell in space group 36.178 Bab21m (BNS
notation). Below TN2 = 52 K the remaining third of the Fe2+ moments (Fe1 site) which are in a
compressed trans-[FeSe4O2] octahedral environment undergo long range ordering, as is evident
from the magnetometry, the Mössbauer spectra and the appearance of new magnetic Bragg peaks
in the neutron diffractograms. The ordering of the second set of moments on the Fe1 sites results in
a slight re-orientation of the majority moments on the Fe2 sites. The magnetic structure at 1.5 K is
described by a 2a × 2b × 2c expansion of the nuclear cell in space group 9.40 Iab (BNS notation)
Хірургічні проблеми вторинного і третинного гіперпаратиреозу в діалізних пацієнтів із хронічною нирковою недостатністю
The aim of the work: to improve the results of surgical treatment of secondary and tertiary hyperparathyroidism in patients with chronic renal failure in treatment of chronic hemodialysis.
Materials and Methods. The study was conducted on the basis of examination of medical records and 89 patients treated at the Department of Nephrology, City Clinical Hospital No. 2, Kryvyi Rih for 2014–2018. All patients were treated CKI using dialysis methods. Among the patients of group 1 66 (74.2 %) patients were on hemodialysis (HD), the group 2 – 23 (25.8 %) on peritonal dialysis (PD). In both groups, men predominated by sex: 49 (55.1 %) and 40 (44.9 %), respectively. The mean age of patients in group 1 with PD was (35±6.4) years, group 2 – with PD – (43±12.4). The mean dialysis period in group 1 was (9.6±2.3) years, in group 2 – (5.4±3.7).
Results and Discussion. Among the main criteria for the surgical treatment of hypeparathyroidism in dialysis patients, clinical, laboratory, and instrumental indicators were identified.Цель работы: определение распространенности гиперпаратиреоза у пациентов с хронической почечной недостаточностью (ХПН), проходивших лечение с использованием диализных технологий и анализ результатов его хирургического лечения.
Материалы и методы. Исследование проведено на основе изучения медицинской документациии 89 пациентов, которые лечились в отделение нефрологии городской клинической больницы № 2 города Кривого Рога за 2014–2018 гг. Все пациенты проходили лечение ХПН с применением диализных методов. Среди пациентов первой группы 66 (74,2 %) больных были на гемодиализе (ГД), второй – 23 (25,8 %) на перитонеальном диализе (ПД). В обеих группах преобладали мужчины: соответственно 49 (55,1 %) и 40 (44,9 %) – женщины. Средний возраст пациентов первой группы по ГД составлял (35 ± 6,4) года, второй с ПД – 43 ± 12,4. Средний срок диализа в первой группе составлял (9,6 ± 2,3) года, во второй – 5,4 ± 3,7.
Результаты исследований и их обсуждение. Среди основных критериев для хирургического лечения гиперпаратиреоза диализных пациентов определены клинические, лабораторные и инструментальные показатели.Мета роботи: визначення поширенності гіперпаратиреозу у пацієнтів з хронічною нирковою недостатністю (ХНН), які проходили лікування з використанням діалізних технологій та аналіз результатів його хірургічного лікування.
Матеріали і методи. Дослідження проведено на основі вивчення медичної документаціїї 89 пацієнтів, які лікувалися у відділенні нефрології міської клінічної лікарні № 2 міста Кривого Рогу за 2014–2018 рр. Всі пацієнти проходили лікування ХНН із застосуванням діалізних методів. Серед пацієнтів першої групи 66 (74,2%) хворих були на гемодіалізі (ГД), другої – 23 (25,8 %) на перитоніальному діалізі (ПД). За статтю в обох групах переважали чоловіки: відповідно 49 (55,1 %) та 40 (44,9 %) – жінки. Середній вік пацієнтів першої групи з ГД складав (35±6,4) року, другої з ПД – 43±12,4. Середній термін діалізу у першій групі складав (9,6±2,3) року, у другій – 5,4±3,7.
Результати досліджень та їх обговорення. Серед основних критеріїв до хірургічного лікування гіперпаратиреозу у діалізних пацієнтів визначено клінічні, лабораторні та інструментальні показники
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