Rearrangement of pentafluoropropionic esters under electron-impact: Confirmation by stable isotope labelling

A rearrangement in the mass spectrum of 1-phenylethyl pentafluoropropionate is discussed together with results obtained by ¹³c and ¹⁸O labelling.     

Universal caterpillars

For a class $\text{C}$ of graphs, denote by u($\text{C}$) the least value of m so that for some graph U on m vertices, every G ? $\text{C}$ occurs as a subgraph of U. In this note we obtain rather sharp bounds on u($\text{C}$) when $\text{C}$ is the class of caterpillars on n vertices, i.e., tree with property that the vertices of degree exceeding one induce a path.     

Manpower planning procedures for hierarchical manpower systems

In this paper, a model which describes manpower planning procedures for a hierarchical system having certain desired properties to be achieved is presented. These properties will act as constraints on the system. It will be assumed that eventual, desired properties are achieved gradually over a period of time. Promotion policies will be wastagelinked and designed to satisfy vacancy-expansion demands. The model will be applied to data from a group of English County Police Constabularies.     

A LEED inquiry into the question of reconstruction of {001} Nb

We have examined the structure of the {001} surface of Nb by LEED and have found that a (1 × 1) diffraction pattern prevails over the entire range of temperature investigated, that is 15–1000 K. This is the first observation of an unreconstructed {001} surface of a bcc metal over such a temperature range. This result is consistent with a reconstruction mechanism requiring the coupling of occupied surface states and is expected to further theoretical development of the mechanism of surface reconstruction.     

Molecular dynamics of a smectic liquid-crystalline side-chain polymer. The dielectric properties of aligned and nonaligned material studied over a wide range of frequency and temperature

The dielectric relaxation behavior of a nonaligned and an aligned liquid-crystalline (LC) polymer are reported for the ranges 10^?3.5 to 10⁵ Hz and 274–363 K. Multiple processes (δ and α) are observed that follow a Vogel equation for the temperature dependence related to the apparent glass transition temperature. The occurrence of these processes and the variation in their relaxation strengths as sample alignment is changed is interpreted in terms of a molecular theory for the dielectric behavior of a LC polymer that involves the director order parameter S_d, the mesophase order parameter S, the dipole moment components of the mesogenic head groups, and their associated relaxation functions.