Thermodynamic scaling of α-relaxation time and viscosity stems from the Johari-Goldstein β-relaxation or the primitive relaxation of the coupling model

By now it is well established that the structural α-relaxation time, τ(α), of non-associated small molecular and polymeric glass-formers obey thermodynamic scaling. In other words, τ(α) is a function Φ of the product variable, ρ(γ)/T, where ρ is the density and T the temperature. The constant γ as well as the function, τ(α) = Φ(ρ(γ)/T), is material dependent. Actually this dependence of τ(α) on ρ(γ)/T originates from the dependence on the same product variable of the Johari-Goldstein β-relaxation time, τ(β), or the primitive relaxation time, τ(0), of the coupling model. To support this assertion, we give evidences from various sources itemized as follows. (1) The invariance of the relation between τ(α) and τ(β) or τ(0) to widely different combinations of pressure and temperature. (2) Experimental dielectric and viscosity data of glass-forming van der Waals liquids and polymer. (3) Molecular dynamics simulations of binary Lennard-Jones (LJ) models, the Lewis-Wahnstr?m model of ortho-terphenyl, 1,4 polybutadiene, a room temperature ionic liquid, 1-ethyl-3-methylimidazolium nitrate, and a molten salt 2Ca(NO(3))(2)·3KNO(3) (CKN). (4) Both diffusivity and structural relaxation time, as well as the breakdown of Stokes-Einstein relation in CKN obey thermodynamic scaling by ρ(γ)/T with the same γ. (5) In polymers, the chain normal mode relaxation time, τ(N), is another function of ρ(γ)/T with the same γ as segmental relaxation time τ(α). (6) While the data of τ(α) from simulations for the full LJ binary mixture obey very well the thermodynamic scaling, it is strongly violated when the LJ interaction potential is truncated beyond typical inter-particle distance, although in both cases the repulsive pair potentials coincide for some distances.     

Dielectric investigation of organic-inorganic hybrid based on titanium oxocluster-crosslinked elastomer

In this paper, we have prepared new type of organic-inorganic hybrid materials based on covalent bond between the two constituents: elastomer and titanium oxocluster. Commercial hydrogenated acrylonitrile-butadiene rubber (HNBR)-Therban^® 3407 was selected as the matrix for mixing the titanium oxocluster. Three different samples containing the elastomer and peroxide, elastomer, peroxide and titanate, and elastomer and titanate, respectively were prepared. The dielectric permittivity have been scanned over a wide range of frequencies and temperatures in order to determine the how the titanate and the peroxide influences the molecular mobility. Complementary DSC and mechanical analysis were performed. We found that the presence of titanates-compounds strongly influences the mobility of the ions and it’s reflected in the low activation energy for the ionic conductivity. In spite that the glass transition temperature is held constant, the temperature dependence of the α process, as well as the free volume at the glass transition, the fragility parameter and the ΔCp during the glass transition are strongly influenced by the composition.     

Electrical and dielectric properties of glass system NaPO3–KHSO4

Glass samples have been prepared in the NaPO₃–KHSO₄ binary system with the classical melting, casting and annealing steps. Electrical and dielectrical properties of glass samples were studied. Measurements of DC and AC conductivity and complex electrical permittivity of xNaPO₃–(100 ? x)KHSO₄ glass system were carried out at temperatures ranging from room temperature to temperature located 15 °C below glass transition temperature T_g. Results showed that changes of NaPO₃ concentration considerably affect values of observed parameters. DC conductivity of glass increases as NaPO₃ concentration grows until concentration x = 60. However, beyond this value a sharp decrease of DC conductivity was observed. In addition relaxation times showed abrupt changes at concentration x = 60, corresponding to the lowest relaxation times at the temperature 90 °C.     

Crystal and molecular structure of 13-oxolupanine

The title compound, C₁₅H₂₂N₂O₂, is monoclinic:P2₁,a=10.876(2),b=8.620(2),c=7.390(2) Å, β=99.2(2)°,Z=2. TheA/B ring junction configuration isquasi-trans, and theC/D junction istrans. RingA has a conformation intermediate between sofa and half-chair; ringsB,C, andD are in chair, boat, and distorted chair conformations, respectively.     

AB initio calculation of the zero-field splittings of the X3Σg− and B3Πg,i states of the S2 molecule

The zero-field splitting of the ³Σ_g^? ground state of S₂ is computed employing MRD CI wavefunctions obtained in a series of AO basis sets. All one- and two-electron spin—orbit interactions are included in the theoretical treatment and results are obtained and compared using second-order perturbation theory techniques and a CI-type diagonalization procedure. The computed data are found to be in good agreement with experiment, including the dependence of the splitting parameter on vibrational quantum number, and are seen to be quite stable with respect to variations in the AO basis as well as the number of inner-shell core orbitals maintained doubly occupied in all Slater determinants employed in the theoretical treatment.     

On fuzzy multi-valued functions Part 1: Introduction and general properties

In this paper a concept of fuzzy multi-valued function is introduced and other related objects are defined. Next their properties, that assume no topological structure, are presented.     

Particular intramolecular interaction in differently P-substituted 2-phosphinoyl (axial)-1,3-dithianes

By X-ray structure elucidation of some of the title compounds unusual short PO---HC distances have been obtained. Concurrently, in the IR spectra of the crystals of these substances very intense CH stretching bands can be detected in certain cases and, simultaneously, there are relatively low wavenumbers of the PO stretching bands. These facts may be taken as an indication of a special molecular interaction. It is the aim of the paper to characterize this molecular interaction by vibrational spectroscopy. The results do not indicate the existence of a real intramolecular hydrogen bond, but they indicate a special activating interaction between the groups mentioned.     

Design and optimisation of multimode 1d photonic band gap waveguide

The modal characteristics of planar waveguides with photonic band gap guiding properties are studied. It is demonstrated that a slight deviation from the periodicity in the photonic band gap multilayers can result in multimode transmission within the guiding layer. Possible applications of the results for avoiding single mode regime destruction due to fabrication process imperfection, as well as for designing such waveguides for conventional and emerging new applications of multimode photonic devices, are pointed out.     

Size‐based separations as an important discriminator in development of proximity ligation assays for protein or organism detection

Proximity ligation is a powerful technique to measure minute concentrations of target protein with high specificity, and it has been demonstrated to be effective on a wide variety of protein targets. The proximity ligation assay (PLA) technique is shown to be compromised by the amplification of a nonspecific fluorescent product that is not indicative of protein presence, which was previously unidentified in a published procedure. This result illuminates the complexity of designing the optimal PLA and the possibility of using a size‐based separation to increase the reliability of PLAs in general. Nucleic acid controls were developed to optimize the assay, which led to a novel end‐point detection method that exploits microchip electrophoresis to size the products. This method provides a greater ability to distinguish a between the target protein's signal and noise in a PLA. The utility of the PLA is demonstrated by the detection of human pathogenic Escherichia coli O157:H7 bacteria, a pathogen at the root of many recent life‐threatening food poisoning outbreaks. The results of the PLA show a detection limit of 100 E. coli O157:H7 cells with minimal cross‐reactivity with gram positive control Staphylococcus aureus bacteria. The advantages of miniaturizing this process are the 100‐fold reduction in volume, greatly reducing reagent requirements, and doubling of the thermocycling speed via noncontact infrared heating. This work, consequently, adds to the understanding of background fluorescence in PLAs, provides a method for evaluating nonspecific amplification, and shows that a qualitative PCR response indicative of the presence protein can be achieved with PLA.