Emission of unbound 8Be and 12C * (0+ 2) clusters in compound nucleus reactions

We have studied the emission of light unbound clusters, ⁸Be and ¹²C ^* (0⁺₂), in the reactions ¹⁸O + ¹³C ^{31} Si ^{23} Ne + ⁸Be and ²⁸Si + ²⁴Mg ^{52} Fe ^{40} Ca + ¹²C ^* (0⁺₂). The -ray spectra obtained in coincidence with ⁸Be and ¹²C ^* (0⁺₂) emission have been studied relative to the statistical emission of two or three -particles. The angular-momentum-to-energy balance of the cluster emission is compared with that of multiple- emission. The properties of the energy spectra of the binary process and the population of the residual nuclei by cluster emission are discussed. It is observed that cluster emission carries away less excitation energy on average than the sequential emission of the individual components.     

Reactions induced by 35 MeV 6He beam on 12C and 14C

The ⁶He+^12,14C scattering and reactions have been studied using a 35 MeV ⁶He radioactive beam and preliminary results are presented. The three-body reaction ⁶He+¹²C ↦ ¹⁰Be+2 α has been clearly identified and sequential decay of intermediate states in ¹⁴C has been studied. Search for an analog reaction on ¹⁴C, ⁶He+¹⁴C ↦ ¹²Be+2 α, has not given conclusive results yet. Other interesting reactions with this entrance channel are discussed.     

Electron field emission from amorphous carbon with N-doped nanostructures pyrolyzed from polyaniline

Carbon-based materials have been of great interest due to their potential application in cold cathodes for field emission displays and other vacuum microelectronic devices. Pyrolyzed polyaniline (PPANI) with N-doped nanostructures was prepared by pyrolysis of polyaniline at high temperature of 900 °C. The morphologies and microstructures were investigated by scanning electron microscopy, transmission electron microscopy, AFM, Raman spectroscopy, and X-ray photoelectron spectroscopy. It was found that there were sp²C-N and sp³C-N bonds between the nitrogen and the carbon atoms in the nanostructures of the PPANI obtained. The electron field emission investigations showed that the turn-on field and effective work function ?_e of PPANI were 1.7 V/μm and 0.010 eV which were lower than N-doped amorphous carbon films obtained by other methods.     

Alpha:2n:alpha molecular band in 10Be

The 10.15 MeV resonance in 10Be has been probed via resonant 6He+4He elastic scattering. It is demonstrated that it is the Jpi=4+ member of a rotational band built on the 6.18 MeV 0+ state. A Gammaalpha of 0.10-0.13 MeV and Gammaalpha/Gamma=0.35-0.46 were deduced. The corresponding reduced alpha width, gamma2alpha, indicates one of the largest alpha-cluster spectroscopic factors known. The deformation of the band, including the 7.54 MeV, 2+ member, is large (h2/2I=200 keV). Such a deformation and the significant degree of clusterization signals a well-developed alpha:2n:alpha molecular structure.     

Proton-proton elastic scattering via the Trojan horse method

We address a successful indirect technique, the Trojan horse method, which allows one to measure the bare nucleus cross section for rearrangement reactions down to astrophysical energies. In particular, we consider here the application of the method to the p-p elastic scattering. This represents an important test of the main feature of the method, namely the suppression of Coulomb effects in the entrance channel due to off-energy-shell effects. In contrast to the on-energy-shell case, the extracted p-p cross section does not exhibit the Coulomb-nuclear interference minimum, as predicted by the half-off-energy shell calculations. This hypothesis is strengthened by the agreement between the Trojan horse p-p data and the calculated on-energy-shell n-n, n-p and nuclear p-p cross sections.     

Minding isometries of ruled surfaces in pseudo-Galilean space

In this paper we study the Minding isometries of skew ruled surfaces in pseudo-Galilean space. The Minding isometries are isometries of ruled surfaces which are also generator-preserving. The obtained results can be easily transfered to the ruled surfaces in Galilean space.     

A conjecture regarding the logarithmic coefficients of univalent functions

One considers the class S of functions, regular and univalent in ¦Z¦<1 and normalized by the expansion f(z)=Z + C₂Z² +.... By the logarithmic coefficients of the function f (z) S one means the coefficients of the expansion Earlier, the author had formulated the following conjecture: for any function f(z) S, for each z (0,1) one has the inequality In this paper this conjecture is proved for spiral-shaped functions and for functions from S with real coefficients and under some additional assumptions.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 125, pp. 135–143, 1983.     

Gas chromatographic determination of fatty acids contained in different lipid classes after their separation by solid-phase extraction

Enthalpic phenomena were shown to contribute to the size exclusion separation mechanisms during chromatographic analysis of solutions of pullulan and cellulose in LiCl-N,N-dimethylacetamide (LiCl-DMAc) solvent and eluent. The effect of LiCl concentration in the sample solutions and the effect of temperature were of the same order of magnitude for both pullulan and cellulose samples. This led to systematic errors in the determination of mean molecular mass in the range of tens of percent, depending on the chromatographic conditions and on the molecular mass of the analyte. The systematic error is much higher than the random errors; the typical values of the latter being up to a few percent (RSD). Low column temperature and a higher content of LiCl in the sample solution led to lower determined mean molecular mass values. This can be explained by a decrease in the interactions between dissolved macromolecules, although polymer-stationary phase interactions should also be taken into account. Furthermore, the cellulose stability in solution was determined: the zero order random degradation constant being k = 6.9 x 10(-8) mol mol-1 monomer day-1.     

A facile and green synthesis route to C@LaCO3OH core-shell microspheres using colloidal carbonaceous spheres as template and its by-products as carbon source

C@LaCO₃OH core-shell microspheres have been synthesized by a hydrothermal method using colloidal carbonaceous spheres (CCSs) as template and its by-products as reactant without any other precipitating agent added in the reaction system. The FT-IR and XRD results indicated the successful formation of the well-crystallized LaCO₃OH shell with hexagonal crystal structure on the CCSs’ surface. The morphology and qualitative elemental chemical analysis were characterized by SEM, TEM, and EDS. The effects of co-solvent on the crystallinity of the LaCO₃OH shell were also studied. In addition, PL result showed one emission band centered at 421 nm (λ_ex = 365 nm) of the C@LaCO₃OH microspheres. The UV–visible spectrum was also employed to investigate the optical property of the products. Further, a possible formation mechanism of the core-shell structure was proposed.