Cluster effects in the angular distribution of alphas scattered from34S

The addition of a resonance scattering contribution to the shape elastic scattering improves the fit in analysing experimental angular distributions. Spins from 7 to 10 ? characterize the resonances, which have a dominant influence on the six analysed angular distributions of 12.80 to 20 meV alpha particles elastically scattered from³⁴S. The relation between the energy of the resonances and their spin compares well with the results from alpha scattering from²⁸Si. As in the scattering from silicon, the occurrence of a dominating spins supports the assumption that they belong to cluster states formed when alpha particles hit the target nuclei.     

Analytic inequalities with applications to special functions

Sharp inequalities are derived for certain (polynomial-like) functions of the real variables p_i (i = 1(1)σ) by interpreting p_i as the probabilities that various switches be thrown in certain directions. Parameters m_v in the inequalities are at first taken to be integers; later the inequalities are established when m_v are arbitrary real numbers. The side condition ∑p_i = 1 occurs throughout analysis, so there are many corollaries. Examples of the inequalities established are

$\text{∑}\text{i=1}\text{σ}\text{(1?p}{}_{\mathrm{i}}{}^{\mathrm{m}}\text{)}{}^{\mathrm{m}}\text{>K?1,}$

valid ifm>1

$\text{∑}\text{j=0}\text{r}\text{n}\text{j}\text{p}{}^{\mathrm{jm}}\text{(1?p}{}^{\mathrm{m}}\text{)}{}^{\mathrm{m?j}}\text{+}\text{1?}\text{∑}\text{j=0}\text{r}\text{n}\text{j}\text{p}{}^{\mathrm{j}}\text{(1?p?s)}{}^{\mathrm{n?j}}{}^{\mathrm{m}}\text{> 1+s}{}^{\mathrm{<mtext>max</mtext><mtext>[m,n]</mtext>}}$

valid if m > 1, n > r + 1, 0 < p, s, p + s ? 1, and also valid if $\text{0 < m < 1, 0 < n < r + 1 (1 ? x)}{}^{\mathrm{u}}\text{+ x}{}^{\mathrm{<mtext>1</mtext><mtext>u</mtext>}}\text{< 1,}\text{if}\text{1}\text{2}\text{< x < 1, u > 1}$. (1.03)     

Multigrid methods for the computation of singular solutions and stress intensity factors II: Crack singularities

We consider the Poisson equation −Δu=f with homogeneous Dirichlet boundary condition on a two-dimensional polygonal domain Ω with cracks. Multigrid methods for the computation of singular solutions and stress intensity factors using piecewise linear functions are analyzed. The convergence rate for the stress intensity factors is whenfεL ²(Ω) and whenfεH ¹(Ω). The convergence rate in the energy norm is in the first case and in the second case. The costs of these multigrid methods are proportional to the number of elements in the triangulation. The general case wherefεH ^m (Ω) is also discussed. The work of the first author was partially supported by NSF under grant DMS-96-00133     

Edman-Abbau als analytische methode in der ‘Solid phase’-Peptidsynthese. Vorläufige Mitteilung

The systematic analysis of solid phase peptide synthesis by Edman degradation becomes possible by the development of a technique (high pressure liquid chromatography) for the determination of phenylthiohydantoins in trace amounts. By its qualitative beside the quantitative results the degradation method offers the possibility to follow formation and propagation of failure sequences over more than one synthetic cycle. Scope and limitations of the method are discussed.     

Molecular dynamics study of the hydration of lanthanum(III) and europium(III) including many-body effects

Lanthanides complexes are widely used as contrast agents in magnetic resonance imaging (MRI) and are involved in many fields such as organic synthesis, catalysis, and nuclear waste management. The complexation of the ion by the solvent or an organic ligand and the resulting properties (for example the relaxivity in MRI) are mainly governed by the structure and dynamics of the coordination shells. All of the MD approaches already carried out for the lanthanide(III) hydration failed due to the lack of accurate representation of many-body effects. We present the first molecular dynamics simulation including these effects that accounts for the experimental results from a structural and dynamic (water exchange rate) point of view.     

Neutron activation analysis for determination of trace elements in sediments in the Sea of Galilee,Israel

The feasibility of applying both thermal and epithermal neutron activation analysis for simultaneous determinations of elemental composition in sediments, collected from the Sea of Galilee (Kineret Lake), Israel, during 1988–1993, was experimentally investigated. In the present work, the concentrations of 30 elements (Al, Ba, Br, Ca, Ce, Co, Cs, Cr, Eu, Fe, Hf, K, La, Lu, Mg, Mn, Na, Nd, Rb, Sc, Si, Sr, Ta, Tb, Th, Ti, U, V, Yb and Zn) in sediments were determined. The validity of the method was checked by analyzing the U.S. NBS Standard Reference Material SRM-1633a; the elemental content found agreed well with the published certified data. Aluminium was determined by reactor neutron activation analysis (RNAA) taking into account the contribution of silicon to the total²⁸Al activity by the²⁸Si(n,p)²⁸Al reaction. Measurements of irradiated mixtures of Si and Al showed that the dependence of log SiAl mass ratio vs. log cadmium ratio (R _Cd) of²⁸Al is almost linear. The data can be analyzed more accurately by a parabolic correlation (log Si:Al mass ratio vs logR _Cd). The concentrations of fission radionuclide¹³⁷Cs, an activation radionuclide¹³⁴Cs (derived from Chernobyl accident) and the naturally occuring radionuclides⁴⁰K,²²⁶Ra and²³²Th in sediments were also measured by -ray spectrometry using Marinelli (Reentrant) Beaker-Sample Containers.     

Generation of alternating groups by pairs of conjugates

Considering the conjugacy classes of the alternating group of degreen, those classes that contain a pair of generators are in the majority. In fact, the proportion of such classes is 1 –(n), and(n) 0 asn .