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1.
Phys Rev Lett ; 118(15): 151801, 2017 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-28452532

RESUMO

T2K reports its first results in the search for CP violation in neutrino oscillations using appearance and disappearance channels for neutrino- and antineutrino-mode beams. The data include all runs from January 2010 to May 2016 and comprise 7.482×10^{20} protons on target in neutrino mode, which yielded in the far detector 32 e-like and 135 µ-like events, and 7.471×10^{20} protons on target in antineutrino mode, which yielded 4 e-like and 66 µ-like events. Reactor measurements of sin^{2}2θ_{13} have been used as an additional constraint. The one-dimensional confidence interval at 90% for the phase δ_{CP} spans the range (-3.13, -0.39) for normal mass ordering. The CP conservation hypothesis (δ_{CP}=0, π) is excluded at 90% C.L.

2.
Phys Rev Lett ; 117(19): 192501, 2016 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-27858422

RESUMO

We report the first measurement of the flux-averaged cross section for charged current coherent π^{+} production on carbon for neutrino energies less than 1.5 GeV, and with a restriction on the final state phase space volume in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso et al., the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. We observe a clear event excess above background, disagreeing with the null results reported by K2K and SciBooNE in a similar neutrino energy region. The measured flux-averaged cross sections are below those predicted by both the Rein-Sehgal and Alvarez-Ruso et al.

3.
Phys Rev Lett ; 116(18): 181801, 2016 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-27203315

RESUMO

T2K reports its first measurements of the parameters governing the disappearance of ν[over ¯]_{µ} in an off-axis beam due to flavor change induced by neutrino oscillations. The quasimonochromatic ν[over ¯]_{µ} beam, produced with a peak energy of 0.6 GeV at J-PARC, is observed at the far detector Super-Kamiokande, 295 km away, where the ν[over ¯]_{µ} survival probability is expected to be minimal. Using a data set corresponding to 4.01×10^{20} protons on target, 34 fully contained µ-like events were observed. The best-fit oscillation parameters are sin^{2}(θ[over ¯]_{23})=0.45 and |Δm[over ¯]_{32}^{2}|=2.51×10^{-3} eV^{2} with 68% confidence intervals of 0.38-0.64 and 2.26-2.80×10^{-3} eV^{2}, respectively. These results are in agreement with existing antineutrino parameter measurements and also with the ν_{µ} disappearance parameters measured by T2K.

4.
Phys Rev Lett ; 110(23): 235002, 2013 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-25167503

RESUMO

Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This has been demonstrated to be due to the formation of helical current filaments flowing along field lines in the scrape-off layer induced by LHW. This leads to the splitting of the outer divertor strike points during LHWs similar to previous observations with resonant magnetic perturbations. The change in the magnetic topology has been qualitatively modeled by considering helical current filaments in a field-line-tracing code.

5.
Phys Rev Lett ; 108(25): 255003, 2012 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-23004608

RESUMO

The application of nonaxisymmetric resonant magnetic perturbations (RMPs) with a toroidal mode number n = 6 in the MAST tokamak produces a significant reduction in plasma energy loss associated with type-I edge localized modes (ELMs), the first such observation with n > 3. During the ELM mitigated stage clear lobe structures are observed in visible-light imaging of the X-point region. These lobes or manifold structures, that were predicted previously, have been observed for the first time in a range of discharges and their appearance is correlated with the effect of RMPs on the plasma; i.e., they only appear above a threshold when a density pump out is observed or when the ELM frequency is increased. They appear to be correlated with the RMPs penetrating the plasma and may be important in explaining why the ELM frequency increases. The number and location of the structures observed can be well described using vacuum modeling. Differences in radial extent and poloidal width from vacuum modeling are likely to be due to a combination of transport effects and plasma screening.

6.
Rev Sci Instrum ; 84(8): 083501, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24007059

RESUMO

This work discusses a new directional probe designed for measurements of fast ion losses and the plasma rotation with a high angular resolution in magnetically confined plasmas. Directional and especially Mach probes are commonly used diagnostics for plasma flow measurements, and their applicability for the fast ion losses detection has been demonstrated. A limitation of static Mach probes is their low angular resolution. At the Tokamak Experiment for Technology Oriented Research, the angular resolution is strongly restricted by the finite number of available measurement channels. In a dynamic plasma, where instabilities can lead to local changes of the field line pitch-angle, plasma flow, or fast ion losses, a low angular resolution makes a precise data analysis difficult and reduces the quality of the measured data. The new probe design, the rotating directional probe, combines the features of early directional probes and Mach probes. It consists of two radially aligned arrays of nine Langmuir probe pins with each array facing opposite directions. During the measurement the probe head rotates along its axis to measure the ion saturation current from all directions. As a result, the rotating directional probe simultaneously provides an angular dependent plasma flow and fast ion losses measurement at different radial positions. Based on the angular dependent data, a precise determination of the current density is made. In addition, the simultaneous measurement of the ion saturation current at different radial positions allows for resolving radially varying field line pitch-angles and identifying the radial dynamic of processes like fast ion losses.

8.
Nurs Res ; 25(1): 35-8, 1976.
Artigo em Inglês | MEDLINE | ID: mdl-1044040

RESUMO

In a study to formulate regression equations which could be used to predict performance on the licensing examinations of graduates of an associate degree nursing program, selected sets of National League for Nursing achievement test scores were found to be effective predictors of state board examination (SBE) scores. When test score records of graduates for the years 1969-1974 were subjected to stepwise multiple regression analysis, prediction equations were empirically validated by correlation of predicted SBE scores with actual SBE scores obtained by graduates of the program.


Assuntos
Logro , Educação em Enfermagem , Avaliação Educacional , Licenciamento em Enfermagem , Probabilidade , Análise de Regressão , Sociedades de Enfermagem , Estados Unidos
9.
Solid State Nucl Magn Reson ; 6(4): 295-308, 1996 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-8902952

RESUMO

This review reflects a long experience with the application of NMR-imaging methods to elastomeric materials. The experimental techniques, used to obtain parameter selective NMR images (T1, T2, T1 rho-images), are described in detail and the methods required for the data analysis are explained. A special emphasis is put on the analysis of experimental errors within the framework of NMR-imaging. In order to make parameter selective images generally useful their information should be correlated to material properties, so that images of the material properties can be obtained. This is demonstrated for the case of crosslink density, which is certainly one of the molecular properties in rubber materials, exhibiting the main influence on mechanical and other material properties. Sulfur cured and carbon black filled technical rubbers with different degree of crosslink density and oxidative aging were investigated using parameter selective in aging techniques. The image data were analyzed by means of gaussian and multiexponential fitting procedures, revealing spatially resolved NMR relaxation parameters. The further interpretation of these parameters was based on physical models describing molecular motions in crosslinked polymers.


Assuntos
Espectroscopia de Ressonância Magnética/métodos , Fenômenos Químicos , Físico-Química , Elasticidade , Microscopia/métodos
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