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Resultados 21-40 de 83252
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Rare-earth tri-iodides-mossbauer effect using /sup 129/i
(1970) [Artigo de periódico] -
g factor of the 50-kev/sub 3/2/-state in /sup 223/ra and the internal magnetic fields at ra nuclei in ferromagnets
(1970) [Artigo de periódico]The y-y perturbed angular correlation of the 236-50-keV cascade in 223Ra has been investigated, yielding g(3/2-, 50 keV) =+0.28 ±0.04. The magnetic hyperfine fields experienced by Ra nuclei embedded in Ni, Co, and Fe ... -
Nuclear relaxation in (nh/sub 4/)/sub 3/hff/sub 7/ studied by gamma-gamma angular correlation
(1970) [Artigo de periódico]Measurements of the perturbed angular correlation have been made for the first 5/2+ excited statc of Ta181 in (NH4) 3HfF7 in arder to solve a controversial question related to the structure of the complex Hf7 this compound. ... -
Exact photocount distributions for laser near threshold
(1970) [Artigo de periódico]Photocount fluctuation problems, treated previously for Gaussian statistics only, or in the limit of short measurement times, have been extended to arbitrary times (compared with the intensity correlation time) and to ... -
Influence of combined static and time-dependent quadrupole interactions on angular correlation in nuclei with integral spin
(1971) [Artigo de periódico]The application of the Bloch-Wangsness-Redfield theory of nuclear relaxation to the study of perturbed angular correlations in even-A nuclei subject to simultaneous static and timedependent quadrupole interactions bas been ... -
Maps of the distribution of atomic hydrogen in a region in centaurus
(1971) [Artigo de periódico]We have made a survey of the region 302° ≤ l ≤ 310°, 2° ≤ b ≤ 12° at the frequency of the hydrogen line. We have detected three elongated features that run parallel to the galactic plane at heights of about 200 pc above ... -
Simple theory of the magnetic properties of rare-earth metals
(1971) [Artigo de periódico]A simple theory for the magnetism of the rare-earth metals is presented. It is based on assuming strongly correlated, well-defined f-electron states of an atomiclike character which are weakly hybridized with conduction-band ... -
Curso de teoria da semelhança
(Edições URGS, 1972) [Livro] -
Degrees of symmetry in quantum field theories
(1972) [Artigo de periódico]A hierarchy of possible symmetries in quantum field theory is defined, which reaches from a purely mathematical invariance to the conventional physical invariance, including the commonly discussed type of spontaneously ... -
Nuclear-quadrupole interactions in perovskite-type compounds of hf/sup 181/ studied by the perturbed-angular-correlation technique
(1972) [Artigo de periódico]Measurements of nuclear-quadrupole-interaction constants in perovskite-type compounds of PbHf03, SnHf03, CaHf03, and SrHf03 have been performed using the perturbed-angularcorrelation technique. A range of fundamental ... -
Observation of the transparency of a resonant medium to zero-degree optical pulses
(1972) [Artigo de periódico]Experiments are described in which low-intensity laser pulses of zero area [f:'m8(z, t) dt=O) are propagated through a degenerate resonantly absorbing medium with greatly reduced absorption. These pulses are constructed ... -
O Papel da classificação na recuperação da informação : classificação facetada
(1973) [Artigo de periódico]Entre as funções próprias das classificações a mais importante é a de possibilitar a construção de linguagens de recuperação, visando a obter informações armazenadas. Torna-se evidente a ineficiência das classificações ... -
Probing the spin-orbit coupling of nuclear protons
(1973) [Artigo de periódico]The strong absorption in quasi-free scattering opens a possibility of measuring the spin-orbit coupling of nuclear protons. Cross sections for polarized incoming protons are expected to exhibit pronounced asymmetries, with ... -
Gm and Inv allotypes of brazilian Cayapo indians
(1973) [Artigo de periódico]Data from 440 individuals belonging to four populations of Brazilian Cayapo Indians are reported. About 99% of them are Gm (1, 21) or Gm (1, 2, 21), while the frequency of sera with Inv (1) varies from 59%7 to 75%. These ... -
Exact photocount statistics : lasers near threshold
(1973) [Artigo de periódico]A previously constructed laser model with quantum (noncommuting) noise sources was shown to lead near threshold to a quantum rotating-wave Van der Pol oscillator. A full dynamical correspondence between quantum and classical ... -
Magnetic breakdown and phase-coherent galvanomagnetic effects
(1973) [Artigo de periódico]This paper presents a generalization of Pippard's network-model approach for the calculation of transport properties in metals in the presence of magnetic breakdown and partial phase coherence of the wave function. The ... -
Study of rare-earth ions implanted into copper, aluminum, silver, and rhodium
(1973) [Artigo de periódico]Various even-even isotopes of Er, Dy, and Yb have been Coulomb excited to their first 2+ states and implanted into metallic foils of Cu, AI, Ag, and Rh. The attenuation of the subsequent y-ray angular distribution was ... -
Study of the hyperfine magnetic field acting on /sup 181/ta nuclei in ni matrix
(1973) [Artigo de periódico]Hyperfine interactions for Ta impurities in a polycrystalline nickel matrix produced by quenching from the melt have been studied using the perturbed-angular-correlation technique. An effective hyperfine field of -89.8 ± ... -
Temperature dependence of the single-crystal elastic constants of co-rich co-fe alloys
(1973) [Artigo de periódico]The single-crystal elastic moduli, C11, C12, and C44 of three fcc cobalt-iron alloys (Co-6 at. % Fe, Co-8 at.% Fe, Co-10 at.% Fe) were measured in the range 0-315 °c. In addition C11 for the Co-6 at. % Fe alloy, and C' = ... -
Proton spin-lattice relaxation in TMMC [(ch/Sub 3/)/Sub 4/Nmncl/Sub 3/]
(1974) [Artigo de periódico]We examine the temperature and frequency dependence of the proton spin-1attice re1axation rate 1/T 1, as a probe of the electron-spin dynamics of the quasi-one-dimensional exchange-coupled paramagnet TMMC [(CH3) 4NMnC1J. ...
