311 research outputs found
Time Reversal Invariance Violating and Parity Conserving effects in Neutron Deuteron Scattering
Time reversal invariance violating parity conserving effects for low energy
elastic neutron deuteron scattering are calculated for meson exchange and
EFT-type of potentials in a Distorted Wave Born Approximation, using realistic
hadronic wave functions, obtained by solving three-body Faddeev equations in
configuration space.Comment: There was a technical mistake in calculations due to singular
behavior of Yukawa functions at short range. We corrected the integration
algorithm. There were some typos which are corrected. arXiv admin note: text
overlap with arXiv:1104.305
A Neutron Interferometric Method to Provide Improved Constraints on Non-Newtonian Gravity at the Nanometer Scale
In recent years, an energetic experimental program has set quite stringent
limits on a possible "non - 1/r^2" dependence on gravity at short length
scales. This effort has been largely driven by the predictions of theories
based on compactification of extra spatial dimensions. It is characteristic of
many such theories that the strength and length scales of such anomalous
gravity are not clearly determined from first principles. As a result, it is
productive to extend the current limits the range and strength of such
hypothetical interactions. As a heavy, neutral, and (almost) stable particle,
the neutron provides an ideal probe for the study of such hypothetical
interactions at very short range. In this work, we describe methods based on
neutron interferometry which have the capability to provide improved
sensitivity non-Newtonian forces down to length scales at and below an
nanometer.Comment: PDF-fil
Nab: Measurement Principles, Apparatus and Uncertainties
The Nab collaboration will perform a precise measurement of 'a', the
electron-neutrino correlation parameter, and 'b', the Fierz interference term
in neutron beta decay, in the Fundamental Neutron Physics Beamline at the SNS,
using a novel electric/magnetic field spectrometer and detector design. The
experiment is aiming at the 10^{-3} accuracy level in (Delta a)/a, and will
provide an independent measurement of lambda = G_A/G_V, the ratio of
axial-vector to vector coupling constants of the nucleon. Nab also plans to
perform the first ever measurement of 'b' in neutron decay, which will provide
an independent limit on the tensor weak coupling.Comment: 12 pages, 6 figures, 1 table, talk presented at the International
Workshop on Particle Physics with Slow Neutrons, Grenoble, 29-31 May 2008; to
appear in Nucl. Instrum. Meth. in Physics Research
Sub-lattice of Jahn-Teller centers in hexaferrite crystal
A novel type of sub-lattice of the Jahn-Teller (JT) centers was arranged in Ti-doped barium hexaferrite BaFe12O19. In the un-doped crystal all iron ions, sitting in five different crystallographic positions, are Fe3+ in the high-spin configuration (S = 5/2) and have a non-degenerate ground state. We show that the electron-donor Ti substitution converts the ions to Fe2+ predominantly in tetrahedral coordination, resulting in doubly-degenerate states subject to the E⊗ e problem of the JT effect. The arranged JT complexes, Fe2+O4, their adiabatic potential energy, non-linear and quantum dynamics, have been studied by means of ultrasound and terahertz-infrared spectroscopies. The JT complexes are sensitive to external stress and applied magnetic field. For that reason, the properties of the doped crystal can be controlled by the amount and state of the JT complexes. © 2020, The Author(s).Deutscher Akademischer Austauschdienst, DAADRussian Foundation for Basic Research, RFBR: 18–02–00332 aDeutscher Akademischer Austauschdienst, DAAD: 91728513Ministry of Education and Science of the Russian Federation, Minobrnauka: 19–53–0401019–72–00055Ministry of Education and Science of the Russian Federation, MinobrnaukaThe authors acknowledge fruitful discussions with A.S. Prokhorov. We acknowledge support of the HLD at HZDR, member of the European Magnetic Field Laboratory (EMFL). At Ural Federal University, the research was supported by the Russian Foundation for Basic Research (18–02–00332 a), UrFU Center of Excellence “Radiation and Nuclear Technologies” (Competitiveness Enhancement Program), the Ministry of Education and Science of the Russian Federation (Program 5–100). In M.N. Miheev Institute of Metal Physics, the research was carried out within the state assignment of the Ministry of Education and Science of the Russian Federation (theme “Electron” No. AAAA-A18–118020190098–5. At South Ural State University, the authors were generally supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0011. The single crystal growth part was supported by Russian Foundation for Basic Research (19–53–04010). At Moscow Institute of Physics and Technology, the work was supported by the Russian Ministry of Education and Science (Program 5–100) and by the German Academic Exchange Service (DAAD) Michael Lomonosov Programm Linie B, 91728513. Time-domain low temperature spectroscopic experiments were financially supported by the Russian Scientific Foundation (19–72–00055)
Therapy chronic trichomoniasis at patients with associated urogenital chlamydial infection
Present material of problem question therapy chronic trichomoniasis. Study clinical and bacteriological effectiveness basic etiotropic preparation and their combination, used in treatment patients trichomoniasis. Found that the combined application antiprotozoal drugs have a more pronounced effect on kills T. vaginalis and shortens the rehabilitation of the patient
Neutron Beta Decay Studies with Nab
Precision measurements in neutron beta decay serve to determine the coupling
constants of beta decay and allow for several stringent tests of the standard
model. This paper discusses the design and the expected performance of the Nab
spectrometer.Comment: Submitted to Proceedings of the Conference CIPANP12, St.Petersburg,
Florida, May 201
Влияние ограничений возможных значений ординат графиков электрической нагрузки на расчетные величины пиков и впадин нагрузки
The influence of limitations on possible theta-ordinate values of group non-uniform electrical load graphs on the rated values of theta peaks and theta troughs and, particularly, on the rated heating load value is considered in the paper. It is shown that neglect of limitations on graph theta- ordinates of an electrical load leads in some cases to errors in evaluation of load theta peaks and theta troughs that exceed the tolerable values by ±10 %. Рассматривается влияние ограниченности возможных значений θ-ординат групповых неоднородных графиков электрической нагрузки на расчетные значения θ-пиков и θ-впадин нагрузки и, в частности, на расчетную нагрузку по нагреву. Показано, что неучет ограниченности θ-ординат графиков электрической нагрузки приводит в ряде случаев к погрешностям в оценке θ-пиков и θ-впадин нагрузки, превышающих допустимую ±10 %
The Nab Experiment: A Precision Measurement of Unpolarized Neutron Beta Decay
Neutron beta decay is one of the most fundamental processes in nuclear
physics and provides sensitive means to uncover the details of the weak
interaction. Neutron beta decay can evaluate the ratio of axial-vector to
vector coupling constants in the standard model, , through
multiple decay correlations. The Nab experiment will carry out measurements of
the electron-neutrino correlation parameter with a precision of and the Fierz interference term to
in unpolarized free neutron beta decay. These results, along with a more
precise measurement of the neutron lifetime, aim to deliver an independent
determination of the ratio with a precision of that will allow an evaluation of and sensitively
test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long
asymmetric spectrometer that guides the decay electron and proton to two large
area silicon detectors in order to precisely determine the electron energy and
an estimation of the proton momentum from the proton time of flight. The Nab
spectrometer is being commissioned at the Fundamental Neutron Physics Beamline
at the Spallation Neutron Source at Oak Ridge National Lab. We present an
overview of the Nab experiment and recent updates on the spectrometer,
analysis, and systematic effects.Comment: Presented at PPNS201
Endoscopic treatment of patients with early forms of gastric cancer
Leningrad regional oncological dispensary, Russia, Al XIII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” și
al III-lea Congres al Societății de Endoscopie, Chirurgie miniminvazivă și Ultrasonografie ”V.M.Guțu” din Republica MoldovaBackground: Currently, most patients with gastric tumors are detected in late stages. Early diagnosis is a major factor in improving
treatment outcomes. On the other hand, patients who are diagnosed on early stages often receive aggressive treatment and are not
subjects to less invasive interventions.
Material and Methods: In our clinic we have been using endoscopic surgery for early gastric cancer since 2009. Japanese colleagues
are the most experienced in this kind of treatment that is why we follow the recommendations of Japanese Gastric Cancer Association
(JGCA). The main criterion provided that endoscopic removal is possible is the depth of tumor invasion. We evaluate the depth of
invasion primarily by endoscopic ultrasonography. According to our data the accuracy of this method is 94%. The main operation used
for the treatment of early gastric cancer is endoscopic submucosal dissection (ESD). Its main advantages are single block resection
within healthy tissues and adequate morphological assessment of the removed tumor. In the last ten years we have performed 148
ESD (145 patients) for early forms of gastric cancer. Surgeries were radical in 95% of cases.
Results:There were no cases of postoperative mortality. Progression of the disease was noted only in one patient. These endoscopic
surgeries have proved to be effective, safe and reasonable in treating early gastric cancer.
Conclusions: Thus, endoscopic surgery significantly reduces the cost of treatment and hospital stay (average - 3.7 days), facilitates
rehabilitation and improves the quality of patients’ life
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