Micellization of alkylated 1.4-diazabicyclo[2.2.2]octane by nuclear magnetic resonance technique using pulsed gradient of static magnetic field

A phenomenon of micellization of 4-aza-1-tetradecyl-1-azoniabicyclo[2.2.2] octane bromide (AB-14) in aqueous solution has been studied by the methods of nuclear magnetic resonance using magnetic field pulse gradient and fluorimetry. The critical micelle concentration is determined; concentration dependences of percentage of free AB-14 molecules and those associated with micelles as well as radii of micelles and numbers of their aggregation are established. Effect of external and internal translational diffusion of molecules on lifetime of AB-14 molecules in micelles is investigated. © 2012 Elsevier B.V

Thermal chamber for material testing

© Published under licence by IOP Publishing Ltd. The problem of ensuring the correct conduct of the experiment with preservation of the required temperature is considered. The construction of the device is proposed that will allow satisfying the conditions for carrying out tensile tests with an increased or lowered sample temperature

Regularity Properties and Pathologies of Position-Space Renormalization-Group Transformations

We reconsider the conceptual foundations of the renormalization-group (RG) formalism, and prove some rigorous theorems on the regularity properties and possible pathologies of the RG map. Regarding regularity, we show that the RG map, defined on a suitable space of interactions (= formal Hamiltonians), is always single-valued and Lipschitz continuous on its domain of definition. This rules out a recently proposed scenario for the RG description of first-order phase transitions. On the pathological side, we make rigorous some arguments of Griffiths, Pearce and Israel, and prove in several cases that the renormalized measure is not a Gibbs measure for any reasonable interaction. This means that the RG map is ill-defined, and that the conventional RG description of first-order phase transitions is not universally valid. For decimation or Kadanoff transformations applied to the Ising model in dimension $d \ge 3$, these pathologies occur in a full neighborhood $\{ \beta > \beta_0 ,\, |h| < \epsilon(\beta) \}$ of the low-temperature part of the first-order phase-transition surface. For block-averaging transformations applied to the Ising model in dimension $d \ge 2$, the pathologies occur at low temperatures for arbitrary magnetic-field strength. Pathologies may also occur in the critical region for Ising models in dimension $d \ge 4$. We discuss in detail the distinction between Gibbsian and non-Gibbsian measures, and give a rather complete catalogue of the known examples. Finally, we discuss the heuristic and numerical evidence on RG pathologies in the light of our rigorous theorems.Comment: 273 pages including 14 figures, Postscript, See also ftp.scri.fsu.edu:hep-lat/papers/9210/9210032.ps.

Micellization of alkylated 1.4-diazabicyclo[2.2.2]octane by nuclear magnetic resonance technique using pulsed gradient of static magnetic field

A phenomenon of micellization of 4-aza-1-tetradecyl-1-azoniabicyclo[2.2.2] octane bromide (AB-14) in aqueous solution has been studied by the methods of nuclear magnetic resonance using magnetic field pulse gradient and fluorimetry. The critical micelle concentration is determined; concentration dependences of percentage of free AB-14 molecules and those associated with micelles as well as radii of micelles and numbers of their aggregation are established. Effect of external and internal translational diffusion of molecules on lifetime of AB-14 molecules in micelles is investigated. © 2012 Elsevier B.V

Micellization of alkylated 1.4-diazabicyclo[2.2.2]octane by nuclear magnetic resonance technique using pulsed gradient of static magnetic field

A phenomenon of micellization of 4-aza-1-tetradecyl-1-azoniabicyclo[2.2.2] octane bromide (AB-14) in aqueous solution has been studied by the methods of nuclear magnetic resonance using magnetic field pulse gradient and fluorimetry. The critical micelle concentration is determined; concentration dependences of percentage of free AB-14 molecules and those associated with micelles as well as radii of micelles and numbers of their aggregation are established. Effect of external and internal translational diffusion of molecules on lifetime of AB-14 molecules in micelles is investigated. © 2012 Elsevier B.V

Micellization of alkylated 1.4-diazabicyclo[2.2.2]octane by nuclear magnetic resonance technique using pulsed gradient of static magnetic field

A phenomenon of micellization of 4-aza-1-tetradecyl-1-azoniabicyclo[2.2.2] octane bromide (AB-14) in aqueous solution has been studied by the methods of nuclear magnetic resonance using magnetic field pulse gradient and fluorimetry. The critical micelle concentration is determined; concentration dependences of percentage of free AB-14 molecules and those associated with micelles as well as radii of micelles and numbers of their aggregation are established. Effect of external and internal translational diffusion of molecules on lifetime of AB-14 molecules in micelles is investigated. © 2012 Elsevier B.V

Thermal chamber for material testing

© Published under licence by IOP Publishing Ltd. The problem of ensuring the correct conduct of the experiment with preservation of the required temperature is considered. The construction of the device is proposed that will allow satisfying the conditions for carrying out tensile tests with an increased or lowered sample temperature