Measurements of high pT light fragments at CM 90° in 800 A MEV C + C collisions

The spectra of high-p_T fragments have been measured at CM 90° in 800 A MeV C + C collisions for p_T up to 1.8 GeV/c (proton), 2.5 GeV/c (deuteron) and 2.8 GeV/c (triton) at the Bevalac. Invariant cross sections were measured down to eight orders of magnitude lower than those for production of low momentum protons. The proton spectrum shows a significant deviation from the Boltzmann shape in the high-energy region. The spectra of deuterons and tritons are explained well by, respectively, squaring and cubing the observed proton spectra.     

Blends of poly(butylene terephthalate) and a polyarylate before and after transesterification

Blends of poly(butylene terephthalate) (PBT) and a copolyester of bisphenol-A with 50% terephthalate-50% isophthalate (PAr), before and after transesterification, have been studied by thermal and dynamic mechanical tests to determine crystallinity and phase behavior. Blends without transesterification, as prepared by solution precipitation, show a single T_g, indicating amorphous miscibility of PBT and PAr. A melting-point depression for PBT crystals is not observed; this means that PBT crystallizes excluding PAr and the entropy of melting is small. The highest fractional crystallinity for PBT is obtained at 20-35% of PAr. Transesterified blends were obtained by holding the physical blends at 250°C for up to 16 h. The transesterified systems show higher T_g's than the corresponding physical blends and also show a marked melting-point depression and lesser PBT crystallinity at the corresponding increased PAr content.     

Indirect determination of sub-ng ml-1 levels of phosphorus in waters by di-isobutyl ketone extraction of reduced molybdoantimonylphosphoric acid an

Reduced molybdoantimonylphosphoric acid is extracted into di-isobutyl ketone (DIBK) and phosphorus in the extract is indirectly determined by inductively-coupled plasma emission spectrometric measurement of the Mo II 202.03-nm or Sb I 206.83-nm line. Washing of the extract with acid is unnecessary because of the low solubility of DIBK in water. Arsenic(III), Si, Ge, Fe(III) and most anions do not cause serious interference but arsenic(V) must be absent. The detection limits are 5.2 and 45 pg P ml^-1, and the relative standard deviations for 1 μg of phosphorus are 2.0% and 2.5%, for molybdenum and antimony measurements, respectively. The method is applied in the analysis of river and seawater.     

Emission spectra of excitons created in a single crystal of KBr by irradiation of heavy ions at 4.2 K

An intensity ratio of the σ- to π-emission higher than that in X-irradiation was observed for a heavy-ion irradiated single crystal of KBr at 4.2 K. The result was interpreted in terms of the interaction of free excitons at higher energy states.