Measurement of the Quasi-free P+n!d+ Reaction near Threshold

Threshold Structure of the Quasi-free P+n!d+ Reaction

ar X iv : 0 80 7 . 07 22 v 1 [ he p - ex ] 7 J ul 2 00 8 Near threshold production of the η meson via the quasi - free pn → pnη reaction

Total cross sections for the quasi-free pn → pnη reaction in the range from the kinematical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pp → ppη reaction by a factor of about three in contrast to the factor of six established for higher excess energies. To large extent, the observed decrease of the ratio σ(pn → pnη)/σ(...

N-sulfonic acid pyridinium-4-carboxylic acid chloride as a novel and efficient catalyst for the condensation reaction of aldehyde with thiobarbituric acid and ammonium acetate

N-sulfonic acid pyridinium -4-carboxylic acid chloride {[Pyridine-N-SO3H-4-COOH]Cl} was synthesized, identified and applied as an effective catalyst for the preparation of pyrido[2,3-d:6,5-d]dipyrimidines by the condensation reaction of various aldehyde with 2-thiobarbituric acid and ammonium acetate under solvent-free conditions.The structure ofcatalyst was studied...

Measurement of the Quasi-free P+n!p+n+ Reaction

The rst measurement of the quasi-free p+n!p+n+ reaction cross section has been made at the CELSIUS storage ring using a deuterium internal cluster jet target. The energy dependence of the cross section is extracted using a xed incident proton energy of T p = 1350 MeV and exploiting the Fermi momentum of the struck neutron. The data cover a range of centre-of-mass excess energies from 16 MeV to ...

Synthesis of Benzopyrano[2,3-d]pyrimidines Using Silica-Bonded N-Propyldiethylenetriamine Sulfamic Acid (SPDTSA) As Heterogeneous Solid Acid Catalyst under Solvent-Free Conditions

Silica-bonded N-propyldiethylenetriamine sulfamic acid (SPDTSA) is employed as a recyclable heterogeneous solid acid catalyst for the synthesis of benzopyrano[2,3-d]pyrimidines  through one-pot condensation reaction of salicylaldehydes, malononitrile and secondary amines  at room temperature under solvent-free conditions. SPDTSA showed much the same efficiency when used in con...