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81.
One of the interesting properties of the NMSSM is that it can accommodate a light pseudoscalar of order 10 GeV. However, such scenarios are challenged by several experimental constraints, especially those related to the fermionic decays of the pseudoscalar. In this Letter, we extend the NMSSM field content by two gauge singlets, with lepton numbers +1 and −1. This serves the twin purpose of generating neutrino masses via the inverse seesaw mechanism and keeping the option of a very light pseudoscalar experimentally viable by opening dominant invisible decay channels of the pseudoscalar which help it evade the existing bounds. 相似文献
82.
83.
The specific heat C and thermal conductivity κ of polybutadiene are characteristic of all non-crystalline materials at temperatures below ≈ K, reflecting the presence of localized excitations. The changes in C and κ with variation in crosslinking suggest that the relaxation times of the localized excitations may vary with crosslink density. Extension of an elastomer does not reveal a change in density of localized excitations as monitored by measuring κ, possibly because other phonon scattering mechanisms mask the effect. For T ? 10 K the phonon mean-free-path is independent of the microscopic anisotropy of the elastomer. 相似文献
84.
The all particle primary nucleon spectrum has been estimated on the basis of the latest Japanese American Emulsion Experiments on the balloon borne emulsion chamber measurements of the fluxes of p, He, C, N, O, Ne, Mg, Si, Fe and low energy fit extrapolated results have been found to follow the power law fit of the formN(E) dE=2·03E
–2·7 dE (cm2 s sr GeV/nucleon)–1. The concept of nuclear fragmentation has been used to estimate the nucleon flux from nuclei spectra. The derived result agrees with the predicted primary spectrum after Yodh, Ellsworth, Stanev and Gaisser.Equipe de Recherche associée au C.N.R.S.Av. H. Fellow, on leave fromIndian Association for the Cultivation of Science, Jadavpur, Calcutta 700032, India. 相似文献
85.
P.J. Daly C.T. Zhang P. Bhattacharyya R. Broda Z.W. Grabowski D. Nisius I. Ahmad M.P. Carpenter L.R. Morss W.R. Phillips J.L. Durell M.J. Leddy A.G. Smith W. Urban B.J. Varley N. Schulz E. Lubkiewicz M. Bentaleb J. Blomqvist 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(2):203-204
Prompt γ-ray cascades in neutron-rich nuclei around doubly-magic 132Sn have been studied using a 248Cm fission source. Yrast states located in the N = 82 isotones 134Te and 135I are interpreted as valence proton and neutron particle-hole core excitations with the help of shell model calculations employing empirical nucleon-nucleon interactions from both 132Sn and 208Pb regions. 相似文献
86.
D. P. Bhattacharyya R. Rakshit B. Basu P. Pal S. Biswas N. Durgaprasad 《Il Nuovo Cimento C》1992,15(3):341-347
Summary A search has been made on the charge-changing partial cross-sections by using 0.927 GeV/n238U ion from LBL BEVALAC projected at an angle 30° on27Al target and CR-39 (DOP) was used as analyser. The irradiated plastic sheets were duly etched for one hour in 6.25N NaOH
solution and about 1680 cone lengths at both the surfaces of the CR-39 (DOP) sheets were optically measured. The cone length
distribution exhibits the existence of U fragments in the charge range 84≤Z≤91 and the estimated partial cross-sections range from 60 to 400 mb. The present data are in accord with the fit to the extrapolated
data of Binnset al. 相似文献
87.
Following Morris’s [5] consideration of a sourceless abelian gauge string in a Robertson-Walker universe with flat space sections
we have generalized the treatment to the case of arbitrary spatial curvature. We find that creation or destruction of the
gauge string is not possible if the spatial curvature is nonzero. 相似文献
88.
57Fe Mössbauer spectra of pulsed-laser deposited (PLD) films of CoFe2O4 of 0.3 µm thickness is investigated using transmission geometry is reported. Mössbauer parameters were determined for the tetrahedral (A) and octahedral (B) sites. The PLD processed films gave measurable spectra with no visible evidence of clustering or multiple phases present. Results on the films agreed with those of the bulk material. The films exhibited magnetic hyperfine and quadruple splittings similar to that of bulk CoFe2O4. This work demonstrates that measurable transmission Mössbauer spectra may be obtained for PLD deposited CoFe2O4 thick films. 相似文献
89.
Nanocrystalline ?-Fe3?x Ni x N (0.0?≤?×?≤?0.8) particles are synthesized by precursor technique and nitridation of decomposed products in NH3 (g) in the temperature range 673 K-823 K. For x?=?0.1–0.4 compositions, single phase ?-Fe3?x Ni x N hexagonal structure with space group P63/mmc is formed, while for x?=?0.5–0.8, fcc γ′-Fe4?y Ni y N phase is also precipitated. The room temperature Mössbauer spectrum for all the compositions shows the presence of superparamagnetic doublet, which is attributed to ?-Fe3?x Ni x N phase. For x?=?0.5–0.8 compositions, two additional sextets are observed corresponding to two different iron sites, the corner position (Fec) and the fcc position (Fef), in γ′-Fe4?y Ni y N. The added Ni atoms preferentially substitute the corner Fec positions. The isomer shift, quadrupole splitting and hyperfine field values are found to change with the Ni content. 相似文献
90.
Synthesis of Nanoscale Bimetallic Particles in Polyelectrolyte Membrane Matrix for Reductive Transformation of Halogenated Organic Compounds 总被引:2,自引:0,他引:2
Nanosized Fe/Ni and Fe/Pd particles were synthesized in the polyacrylic acid (PAA)/polyether sulfone (PES) composite membrane matrix for reductive transformation of halogenated organic compounds (HOCs). The advantages of using membrane to immobilize nanoparticles are the reduction of particles loss, prevention of particles agglomeration, and potential application of convective flow. Cross-linked PAA/PES composite membranes containing metal ions as particles precursor were prepared by heat treatment with ethylene glycol (EG) as a cross-linking agent. Nanoscale metal particles were formed and immobilized inside the membrane matrix after reduction with sodium borohydride. Membrane morphology and structure were observed by scanning electron microscopy (SEM). Particle size and distribution were characterized by SEM and transmission electron microscopy (TEM). Energy dispersive X-ray spectroscopy (EDS) was used to obtain the qualitative and quantitative element information of particles. A specimen-drift-free EDS line profile and EDS mapping system was performed in a scanning transmission electron microscopy (STEM) to determine the two-dimensional element distribution of iron and nickel in the nano domain. In the dechlorination study with trichloroethylene (TCE) as a representative HOCs, rapid and complete destruction of TCE was achieved by using nanosized bimetallic Fe/Ni or Fe/Pd in PAA/PES composite membranes. Typically more than 95% of 10 mg/l TCE was reduced within 1 h. Ethane was found in the headspace as the main product. 相似文献