Synthetic approach to grayanotoxins: a new method for the construction of the a-homograyanotoxane ring system

The A-homograyanotoxane ring system was constructed by a thermolysis of benzocyclobutene, followed by a Wagner-Meerwein rearrangement of the resulting kaurane type of compound.     

Measurement of polarized target asymmetry on γn→π−p around the second resonance region

The polarized target asymmetry for γn→π^?p was measured over the second resonance region from 0.55 to 0.9 GeV at pion c.m. angles between 60° and 120°. A double-arm spectrometer was used with a deuterated butanol target to detect both the pion and the proton, thus considerably improving the data quality. Including the new data in the amplitude analysis, the radiative decay widths of three resonances were determined more accurately than before. The results are compared with various quark models.     

Sample preparation in routine analysis for quartz in dust by x-ray diffractometry

To achieve better reproducibility in the x-ray diffractometric determinations of quartz, the particle size of samples and of the internal standard substance, and the pore size of filters, should be set in the ranges <10 μm and 0.5–0.8 μm, respectively with loadings less than 10 mg cm^?2.     

Limits on the production of large transverse momentum direct photons deduced from the measurement of low-mass electron pairs

The hadronic production of electron pairs with masses between 200 and 500 MeV and large transverse momentum has been measured at the CERN Intersecting Storage Rings (ISR). The expected relation between low-mass electron pairs and real photons is used to determine the direct hadronic production of photons. Contrary to indications from some previous experiments, the observed spectrum is consistent with expectations from the decay of known mesons, and leads to a value for the ratio of direct photons to π⁰ of γ/π⁰ = (0.55 ± 0.92)% for 2 < p_T < 3 GeV and 〈√s〉 = 55 GeV.     

Azimuthal correlation of a high pTπ0 and η with a second π0 produced in pp collisions at the ISR

The correlation between a high transverse momentum π⁰and η and a second π⁰ have been measured using an apparatus with large azimuthal acceptance. The angular distribution of α, measuring the deviation from collinearity in azimuth, peaks near zero. The r.m.s. of the distribution is found to have an inverse logarithmic rather than a $\text{1}\text{p}$ fall-off.     

Structural study of Si(1 1 1)-6 × 1-Ag surface using surface X-ray diffraction

The surface structure of Si(1 1 1)-6 × 1-Ag was investigated using surface X-ray diffraction techniques. By analyzing the CTR scattering intensities along 00 rod, the positions of the Ag and reconstructed Si atoms perpendicular to the surface were determined. The results agreed well with the HCC model proposed for a 3 × 1 structure induced by alkali-metals on a Si(1 1 1) substrate. The heights of the surface Ag and Si atoms did not move when the surface structure changed from Si(1 1 1)-√3 × √3-Ag to Si(1 1 1)-6 × 1-Ag by the desorption of the Ag atoms. From the GIXD measurement, the in-plane arrangement of the surface Ag atoms was determined. The results indicate that the Ag atoms move large distances at the phase transition between the 6 × 1 and 3 × 1 structures.