Search for the ρρ enhancement near 1700 MeV/c in the reaction at 8.3 GeV/c

Results are presented from a search for a ρ⁰ρ⁰ enhancement in antiproton annihilations. A ρ⁰ρ⁰ resonance was recently observed in radiative ψ decays, and its existence has been supported by the results of an antiproton experiment at 5.7 GeV/c. No indication of this ρ⁰ρ⁰ enhancement is seen is our data, in direct contradiction with the earlier, lower statistics experiment.     

Über die Multiplikatorensysteme zur Gruppe der ganzen Modulsubstitutionenn-ten Grades

Ohne Zusammenfassung     

Un nouveau theoreme d'echantillonnage pour le degre de coherence complexe en vue de la reconstitution d'une source lumineuse isotrope

We present some results obtained by using the standard technique of light scattering on so-called “microemulsions”. From the data of single-photon counting of light scattered from 0° to 90° the particle scattering factor P(θ) is obtained. Fitting with the theoretical curves gained for various kinds of particles enables us to deduce in a rather direct and simple way the shape and the size of particles.     

Optically active alternating copolymers of maleic anhydride and alkylvinylethers

Maleic anhydride (MAn) was copolymerized in benzene solution at 60° using AIBN with some optically active alkylvinylethers (RVE) having an asymmetric carbon atom at the α, β, γ or δ position with respect to the oxygen atom [R = (S)-1-methylpropyl, (R)-1-methylbutyl, (S)-2-methylbutyl, (S)-3-methylpentyl, (S)-4-methylhexyl, (S)-1-methylheptyl and (S)-3,7-dimethyloctyl]. Chemical compositions and solubilities of the polymeric products as well as optical rotation properties and spectroscopic measurements (i.r. and NMR) confirmed the formation of copolymers with a predominantly alternating structure. Two Cotton effects of low but definite intensity attributable to $\text{n → π}{}^1$ electronic transitions of carbonyl groups of anhydride moieties were observed between 200 and 250 nm. Failure to achieve complete cleavage of chiral side chains does not enable us to attribute the induced optical activity of anhydride moieties either to the asymmetric carbon atom present in the side chain or to the tertiary chiral centres present in the main chain or both.     

Studies of silicophosphate derivatives by 31P-->29Si CP MAS NMR

We show that it is possible to efficiently transfer magnetization from ³¹P to ²⁹Si, using variable amplitude CP MAS experiment. This experiment is demonstrated by using Si₅O(PO₄)₆, the synthesis protocol of which is described. From the obtained results, we show that the experiment allows the spectral edition of ²⁹Si spectra from ³¹P→²⁹Si CP, enabling the studies of derivatives involving Si–O–P linkages, such as phosphosilicate glasses, microporous silicoaluminophosphates (SAPO) and bioactive phosphosilicates.     

Cumulative "roof effect" in high-resolution in vivo 31P NMR spectra of human calf muscle and the Clebsch-Gordan coefficients of ATP at 1.5 T

NMR spectra of non-weakly coupled spin systems exhibit asymmetries in line intensities known as "roof effect" in 1D spectroscopy. Due to limited spectral resolution, this effect has not been paid much attention so far in in vivo spectroscopy. But when high-quality spectra are obtained, this effect should be taken into account to explain the quantum-mechanical fine structure of the system. Adenosine 5'-triphosphate (ATP) represents a 31P spin system with multiple line splittings which are caused by J-couplings of medium strength at 1.5 T. We analyzed the ATP roof effect in vivo, especially for the beta-ATP multiplet. The intensities of its outer resonances deviate by ca. 12.5% from a symmetrical triplet. As this asymmetry reflects the transition from Paschen-Back to Zeeman effect with total spin that is largely broken up, the Clebsch-Gordan coefficients of the system can be indicated in analogy to the hyperfine structure of hydrogen. Taking the roof effect into account, the chi2 of fitting in vivo ATP resonances is reduced by ca. 9% (p<0.005).     

Enhancing sonochemical activity in aqueous media using power-modulated pulsed ultrasound: an initial study

Relatively little is known about the effects of pulsed ultrasound on the facilitation of chemical reactivity. Previous studies have indicated that sonochemistry using pulses is generally less effective than continuous ultrasonic irradiation. However, the pulse trains employed were such that the peak power of the pulses was the same as the maximum power used in continuous irradiation. As a result, less acoustic energy was transmitted to the solutions over the same period of time. The effectiveness of ultrasound when the pulse is adjusted so that the same amount of acoustic energy is input compared to continuous irradiation over a given time has not been previously explored. In this study we have embarked on an examination of the efficacy of power-modulated pulsed (PMP) sonochemistry. Specifically, we have explored the effects of pulse type and pulse frequency on the oxidation of potassium iodide and the degradation of acid orange, a common industrial colorant. A rate increase by a factor of three was observed compared with continuous irradiation under conditions of equivalent acoustic input power.