Absolute cross sections for isotopically identified products formed in multinucleon transfer in the (136)Xe+(198)Pt system at ∼8 MeV/nucleon are reported. The isotopic distributions obtained using a large acceptance spectrometer demonstrated the production of the "hard-to-reach" neutron-rich isotopes for Z<78 around the N=126 shell closure far from stability. The main contribution to the formation of these exotic nuclei is shown to arise in collisions with a small kinetic energy dissipation. The present experimental finding corroborates for the first time recent predictions that multinucleon transfer reactions would be the optimum method to populate and characterize neutron-rich isotopes around N=126 which are crucial for understanding both astrophysically relevant processes and the evolution of "magic" numbers far from stability.
Proton resonant states in 27 P were studied by the resonant elastic scattering of 26 Si + p with a 26 Si radioactive ion beam bombarding a thick H 2 gas target with the inverse kinematics method. The properties of these resonance states are important to better constrain the production rates of the 26 Si(p,γ ) 27 P reaction. This is one of the astrophysically important reactions needed to understand proton-rich nucleosynthesis such as the galactic production of 26 Al and energy generation in explosive stellar environments. Although there are recent studies on the resonant structure in 27 P, large uncertainties remain, and only a few levels are known. In this work, resonant states were observed over the excitation energies range of 2.3 to 3.8 MeV with high statistics and without background contamination within the target. The resonance parameters were extracted by an R-matrix analysis of the excitation function. The 26 Si(p,γ ) 27 P stellar reaction rate has been evaluated, including high-lying resonances found in this work.
The half-life of the 4 + 2 state of the 2p − 2h proton intruder band of 116 Sn has been measured for the first time with the fast-timing technique. The lifetime of T 1/2 = 29(10) ps leads to a transition probability B(E2; 4 + 2 → 2 + 2 ) = 40(13) Weisskopf units, which is in very good agreement with the large B(E2; 2 + 2 → 0 + 3 ) value measured previously and provides strong support for the 0 + 3 state as the band-head of the intruder configuration and for the shape coexistence in the semi-magic 116 Sn nucleus. IBM-2 calculations with mixing reproduce the experimental data very well, giving insight into the degree of mixing between the different states.suggested that they were built on intruding 2p − 2h proton excitations across the Z = 50 closed shell. Subsequent detailed spectroscopy using light-ion reactions and detecting both the γ-ray and conversion electron decays of the low-lying 0 + and 2 + levels, [9][10][11], provided firm evidence, summarized by Julin [12], for the deformed shapes of the intruder bands through the observation of enhanced E0 transitions.
A new method is proposed for effective analysis of laminated plates incorporating accurate through-thethickness distribution of displacements, strains and stresses in the finite element formulation. It is a two-step analysis procedure. In the first step, displacements are obtained using a post-processing procedure based on the three-dimensional stress equilibrium equations and the thermoelasticity equations, from the results of FSDT finite element analysis. In the second step, the higher-order through-the-thickness distribution of displacements are reflected on the subsequent finite element analysis. The effectiveness of the present approach for the analysis of laminated plates is shown by numerical examples. IntroductionNumerous approaches have been proposed for studying the through-the-thickness behavior of laminated composite and sandwich plates. These approaches include those using (1) finite element analysis based on three-dimensional continuum mechanics, (2) finite element analysis based on quasi-three-dimensional models or higher-order twodimensional models and (3) finite element analysis based on two-dimensional or shell models based on classical laminate plate theory (CLPT) or first order shear deformation theory (FSDT) combined with post-processing procedures. Description of the various computational approaches can be found in several survey papers (Kapania, Three-dimensional or quasi-three-dimensional finite element analysis can become computationally expensive for problems with complicated geometry, especially for laminates with large number of layers.Finite element analysis based on two-dimensional finite element models or shell models based on first order shear deformation theory has limited accuracy as the thickness increases or for sandwich plates. Particularly, accurate evaluation of transverse stresses cannot be expected. Twodimensional finite element analysis used in conjunction with post-processing procedures based on the integration of the three-dimensional stress equilibrium equations or predictor-corrector procedures based on the threedimensional stress equilibrium equations and the threedimensional thermoelasticity equations have been proposed (Engblom and Ochoa, 1985;Chaudhuri, 1986;Noor et al., , 1994 Kim, 1999, 2000). Also proposed are the methods based on obtaining transverse shear stresses directly from transverse shear forces, reducing the required order of derivatives of interpolation functions in the stress equilibrium type post-processing methods for the evaluation of transverse normal stress (Rolfes and Rohwer, 1997; Rolfes et al., 1998a, b). The proposed approaches could enhance the accuracy of the through-the-thickness responses considerably. However, even for the most advanced post-processing techniques, the final accuracy of the results are bounded by the limitation of the initial finite element results which are based on a simplified model. This is more true especially for the transverse normal stress in thermally loaded laminates. To overcome the restraint of the initial an...
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