A new general method for synthesis of ketene dithioacetal

Dithioacetals ($\text{1}$) were treated with n-butyllithium and 2,2′-dipyridyl disulfide to give ketene dithioacetals ($\text{3}$) in high yields, which constituted a new efficient synthetic method for the latter compounds.     

The vertex bootstrap conditions in the dual unitarisation scheme

The bootstrap conditions for the triple- and double-Regge vertices are derived utilising the planar unitarity condition for six- and five-point amplitudes. The problem of symmetry breaking is considered within the one-dimensional approximation. It is shown that the vertex and propagator equations together predict the equal spacing rule for Regge trajectory intercepts and a well defined pattern of symmetry breaking for vertices.     

On the cyclotron resonance width of very pure Ge

The temperature variation of the cyclotron resonance width Γ for a very pure semiconductor is calculated numerically based on the earlier theory [S. Fujita & A. Lodder, Physica83B, 117 (1976)]. The results are in excellent agreement with experiments by Kawamura et al. for very pure Ge.     

Soft-gluon effects in nonleptonic decays of charmed mesons

Soft-gluon effects in nonleptonic decays of D and F mesons are studied nonperturbatively by use of a QCD multipole expansion. For reasonable values of D-meson bound-state parameters, the soft-gluon effects lead to a significant difference in the lifetimes of the D⁰ and D⁺ mesons.     

Notes on polymer hydrodynamics

The sedimentation of an unperturbed polymer chain in dilute solution is reformulated by using Burgers' method, in which the no-slip boundary condition on the surface of each chain element is taken into account approximately. It is shown that the forcevelocity proportionality relation employed so far as the basis of theoretical developments in polymer hydrodynamics can be justified as a first approximation to the no-slip condition. The derived expression for the translational friction coefficient f_t is a complex function of n and a/b, where n is the number of chain elements in a single molecule and a/b is the ratio of the Stokes radius of a chain element to the effective bond length. Three special cases corresponding mathematically to b = ∞ (no hydrodynamic interaction), a ? b (Kirkwood-Riseman theory), and b = 2a (touching-sphere model) are examined in detail. Finally, it is shown that when a/b = 0.2360, our f_t varies linearly with n^1/2 over the entire range of n.     

Meta/para-selectivity variation by sulfide/sulfoxide conversion of 6-substituted β-cyclodextrin. Hydrolyses of nitrophenyl acetates. ag

Hydrolyses of m- and p-nitrophenyl acetates by 6-deoxy-6-alkylthio-β-cyclodextrins and the corresponding sulfoxides were studied to show that the small chemical conversion from the sulfides to the sulfoxides led to a change of meta/para-selectivity in the hydrolysis of the β-cyclodextrin moiety.