On the importance of indirect processes in one particle transfer reactions induced by heavy ions

The reaction ⁹⁶Zr(¹⁶O, ¹⁵N) ⁹⁷Nb to the …1g ${}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}$ ?3^? (⁹⁶Zr);j〉 septulet is calculated in the coupled channel Born approximation. Direct and indirect transfer processes are found to be of the same order of magnitude and show similar j-dependence.     

Characterization of a potentially axially symmetric europium(III) complex of a tetraacetate,tetraaza, macrocyclic ligand by luminescence excitation,emission and lifetime spectroscopy

The Eu(III) complex of the octadentate macrocyclic ligand, 1,4,7,10-tetraazacyclododecane-N,N',N'',N''' -tetraacetate, DOTA, has been examined by luminescence excitation, emission, and lifetime spectroscopy using pulsed dye laser techniques. The results confirm the expected axially symmetric nature of the major component in solution and reveal that 1.2 ± 0.4 water molecules arc coordinatcd to the Eu(III) ion in the complex.     

On the role of the pairing modes in the (h92 ⊗ 3−) multiplet of 209Bi

A unified picture of the low lying states of ²⁰⁹Bi is attempted in terms of surface and pairing vibrations as well as particle and hole degrees of freedom.     

Oxidative polymerization of aromatic hydrocarbons: A study of kinetics and mechanism

Aromatic hydrocarbons were homopolymerized by means of an oxidative polymerization reaction with the use of the catalyst system anhydrous aluminum chloride–cupric chloride. The kinetics of the benzene homopolymerization carried out under different experimental conditions was followed by the determination of the amounts of cuprous ion and polymeric product formed in the reaction. Cuprous ion was spectrophotometrically titrated in the form of its complex with 2,2′-biquinolyl (cuproine). The experimental results do not agree with cationic mechanism for this reaction previously proposed in the literature. Ethylbenzene was kinetically studied under the same experimental conditions. In view of the experimental evidences obtained in this work and on some literature data, a mechanism based on formation of cation-radicals is proposed for the oxidative polymerization reaction when carried out under the studied conditions.     

Testing and application of the nuclear field theory: The nuclei 91Nb and 211Pb

A method is presented for summing up the whole nuclear field theory series for the case of three particles outside a closed shell. The method is first illustrated within a simple model and then applied to the nucleus ⁹¹Nb. In all the cases it is shown that the theory properly corrects the Pauli principle violations and the resulting overcompleteness of the basis. Finally, the application of the method in the analysis of the spectrum of ²¹¹Pb gives a reasonable account of the experimental features. This last application also shows that the first-order perturbation method is in good agreement with the full application of the theory.     

Natural Polymer Characterization

Summary : A review about the characterization of natural polymers is given, describing the polymers found in Nature, methods to distinguish natural from syntheticpolymers, and what modern Polymer Science can learn from Nature     

Alpha-particle decays from excited states in 24Mg

Using a cluster model based on the Woods-Saxon potential, alpha-particle decays from excited states in ²⁴Mg have been systematically investigated. Calculations can in general reproduce experimental data, noticing the fact that the preformation factor P of alpha particle in alpha-decaying nuclei is of order from 10⁰ to 10⁻². This can be the evidence for the α+²⁰Ne structure in ²⁴Mg. Meanwhile, the results also show the existence of other configurations, such as ¹⁶O+2α. Since the calculated decay widths are very sensitive to the angular momentum carried by the outgoing cluster (α particle), our results could serve as a guide to experimental spin assignments.

     

Bounding the exponent of a verbal subgroup

We deal with the following conjecture. If \(w\) is a group word and \(G\) is a finite group in which any nilpotent subgroup generated by \(w\) -values has exponent dividing \(e\) , then the exponent of the verbal subgroup \(w(G)\) is bounded in terms of \(e\) and \(w\) only. We show that this is true in the case where \(w\) is either the \(n\text{ th }\) Engel word or the word \([x^n,y_1,y_2,\ldots ,y_k]\) (Theorem A). Further, we show that for any positive integer \(e\) there exists a number \(k=k(e)\) such that if \(w\) is a word and \(G\) is a finite group in which any nilpotent subgroup generated by products of \(k\) values of the word \(w\) has exponent dividing \(e\) , then the exponent of the verbal subgroup \(w(G)\) is bounded in terms of \(e\) and \(w\) only (Theorem B).     

Commutators and pronilpotent subgroups in profinite groups

Let \(G\) be a profinite group in which all pronilpotent subgroups generated by commutators are periodic. We prove that \(G^{\prime }\) is locally finite.     

How Climatic Seasons of the Amazon Biome Affect the Aromatic and Bioactive Profiles of Fermented and Dried Cocoa Beans?

In addition to the vast diversity of fauna and flora, the Brazilian Amazon has different climatic periods characterized by periods with greater and lesser rainfall. The main objective of this research was to verify the influence of climatic seasons in the Brazilian Amazon (northeast of Pará state) concerning the aromatic and bioactive profiles of fermented and dried cocoa seeds. About 200 kg of seeds was fermented using specific protocols of local producers. Physicochemical analyzes (total titratable acidity, pH, total phenolic compounds, quantification of monomeric phenolics and methylxanthines) and volatile compounds by GC-MS were carried out. We observed that: in the summer, the highest levels of aldehydes were identified, such as benzaldehyde (6.34%) and phenylacetaldehyde (36.73%), related to the fermented cocoa and honey aromas, respectively; and a total of 27.89% of this same class was identified during winter. There were significant differences (p ≤ 0.05, Tukey test) in the profile of bioactive compounds (catechin, epicatechin, caffeine, and theobromine), being higher in fermented almonds in winter. This study indicates that the climatic seasons in the Amazon affect the aromatic and bioactive profiles and could produce a new identity standard (summer and winter Amazon) for the cocoa almonds and their products.