Construction of Helically Stacked π-Electron Systems in Poly(quinolylene-2,3-methylene) Stabilized by Intramolecular Hydrogen Bonds

π-Stacked polymers, which consist of layered π-electron systems in a polymer, can be expected to be used in molecular electronic devices. However, the construction of a stable π-stacked structure in a polymer is considerably challenging because it requires sophisticated designs and precise synthetic methods. Herein, we present a novel π-stacked architecture based on poly(quinolylene-2,3-methylene) bearing alanine derivatives as the side chain, obtained through the living cyclo-copolymerization of an o-allenylaryl isocyanide. In the resulting polymer, the neighboring quinoline rings of the main chain form a layered structure with π–π interactions, which is stabilized by intramolecular hydrogen bonds. The vicinal quinoline units form two independent helices and the whole molecule is a twisted-tape structure. This structure is established on the basis of UV/CD spectra, theoretical calculations, and atomic-force microscopy.     

Charged particle activation analysis of boron and carbon on the surface of silicon wafer

Boron and carbon on the surface of silicon wafers in ordinary atmospheres were measured by activation with the¹⁰B(d,n)¹¹C and¹²Cd(d,n)¹³N reaction, respectively. Two sample plates in intimate contact were bombarded by deuterons, and the¹¹C or¹³N formed at the inside surfaces were measured after chemical separation. From 1.2·10¹³ to 8.4·10¹³ atoms/cm² of boron and from 2.4·10¹⁴ to 6.1·10¹⁵ atoms/cm² of carbon were found ,and the sensitivity was extended down to 5·10¹² and 3·10¹² atoms/cm² for boron and carbon, respectively.     

Turbulence structure of air-water bubbly flow—III. transport properties

An experimental study of heat and bubble transport in turbulent air-water bubbly flow was carried out by means of tracer techniques. Helium tracer gas concentration data and temperature distributions were used to extract bubble and heat diffusivity information. The results indicated that the turbulent velocity components of the liquid phase play a predominant role in the turbulent transport process. A systematic increase of diffusivity of heat, ?_H, with quality and water velocity was observed. An empirical correlation for the diffusivity ratio ?_H,TP/?_H,SP is presented. The Péclet number, u′_covbar|dφ, for bubble dispersion can be approximated by 2.0, independent of the flow variables. The bubble-to-heat diffusivity ratio, φ/?_H, approaches unity with increasing quality and water velocity. Momentum transport is also discussed, based on a mixing length theory.     

Ultrasonic studies of membrane suspensions

Summary The mechanical and the dynamic properties of various membranes were studied by the ultrasonic-resonance method. The compressibility of the membranes was in the range from 2.5·10⁻¹¹ to 5·10⁻¹¹ cm²/dyn and influenced by several factors such as phase transition, incorporation of cholesterol or proteins and configuration of proteins. The ultrasonic relaxation was measured for two membrane systems, dipalmitoylphosphatidylcholine bilayer and sarcoplasmic-reticulum membrane. The results indicated that the ultrasonic measurements are very sensitive to the co-operative transition in lipid bilayers as well as the relaxation of biological membranes containing intrinsic proteins. Paper presented at the ?Meeting on Lyotropics and Related Fields?, held in Rende, Cosenza, September 13–18, 1982.     

Non-stereospecific ring expansions of benzothiazoline sulfoxides

Non-stereospecific ring expansions of 3-acetylbenzothiazoline sulfoxides to benzothiazines from the reaction with acetic anhydride are reported.