Some salient features of antiproton-nucleon annihilations

We have studied pion production data from $\text{p}\text{p}$ and $\text{p}\text{n}$ annihilation between 1.51 and 2.90 GeV/c. The gross features of the data indicate that mechanism for antiproton-nucleon annihilations are primarily of statistical nature.     

The Ar(p, d)Ar reaction

The ³He spin analysing power of hydrogen (protons) has been measured at a c.m. energy of 20 MeV at 14 c.m. angles from 40° to 160°. The measurement of ³He target polarization was calibrated by measuring the ³He spin analysing power of ⁴He at an energy and angle where it was ?1.00. The proton-³He differential elastic scattering cross section is also reported at a c.m. energy of 20.0 MeV for 36 c.m. angles from 20° to 170°.     

Large lanthanide-induced chemical shifts in cobalt complexes of enethials (α,β-unsaturated thioaldehydes)

Eu(fod)₃-, Yb(fod)₃- and Pr(fod)₃-induced chemical shifts of the ‘thioaldehydic’ protons in enethial ligands complexed to a cobalt cyclopentadienyl group are unusually large and in the same direction (10–30 ppm downfield per mole of shift reagent per mole of substrate). The shifts of the protons induced by Eu(fod)₃ and Pr(fod)₃ in the enethial ligands show an alternation in sign on proceeding away from the sulfur atom. In contrast to the results with the fod reagents, the ytterbium and lanthanum shift reagents Yb(thd)₃ and La(thd)₃ caused only small shifts of protons in the 2-phenylpropenethial ligand. No induced shifts with the Eu or Pr reagents were observed for a cyclopentadienyl cobalt complex of dithioglyoxal. The induced shifts in these enethial complexes may be caused by varying blends of complex formation, contact and pseudocontact shifts. Caution is advised in assigning origins to lanthanide induced shifts in such organometallic systems.     

Observation and assignment of phonon combination bands in the far infrared dielectric response of GaAs

A determination by dispersive Fourier transform spectroscopy of the frequency dependence of the anharmonic self-energy of the q??O transverse optic phonon in GaAs at 300 and 6 K is presented. The measured self-energy function is compared with the two-phonon density of states function calculated from an 11-parameter rigid ion model, and the model is found to account satisfactorily for all features in the measured spectrum as phonon combination bands.     

Cycloadditions of non-stabilized azomethine ylides and quinones synthesis of the Reniera isoindole

Azomethine ylides, generated from cyanomethylamino silanes and excess silver fluoride, undergo cycloaddition with quinones to give, after oxidation $\text{in situ}$, quinonoid isoindoles. This reaction provides the key step for a short, high yield synthesis of the $\text{Reniera}$ isoindole 1a.     

Annelative Phenol Synthesis : Preparation of 7-methyljuglone and 7,9,11 Trideoxydaunomycinone

The Michael adducts of arylacetonitrile enolates and unsaturated esters may be converted to fused phenolic systems by the following sequence: ester hydrolysis, Na/NH₃ reductive elimination of cyanide, Friedel-Crafts ring closure, and oxidation. The construction of linear polycyclic systems by this annelation procedure is illustrated by the regiospecific syntheses of 7-methyljuglone and $\text{dl}$-7,9,ll-trideoxydaunomy- cinone.     

The morphology and electrical properties of heteroepitaxial InAs prepared by MBE

An investigation of the growth of heteroepitaxial InAs by MBE is reported. The surface morphology and electrical properties are shown to be critically dependent on growth parameters and the conditions necessary to obtain good material quality are deduced. Analysis of the thickness dependence of the electrical properties of undoped, and Si- or Te-doped InAs shows that interfacial effects contribute to the measured properties. Material remote from the interfacial region compares favourably with VPE- and bulkgrown InAs.     

Focal shifts in diffracted converging spherical waves

It is known that when a converging, monochromatic, spherical wave is diffracted at a circular aperture, the point of maximum intensity may not be at the geometric focus of the incident wave, but may be located closer to the aperture. In the present note this effect is calculated using somewhat simpler mathematical procedures than have been used in previous publications. The result is interpreted as the combined effect of diffraction and the inverse square law.