Pyrene containing liquid crystalline asymmetric phthalocyanines and their composite materials with single-walled carbon nanotubes

In the present work we have studied the dispersion of single-walled carbon nanotubes in liquid crystalline asymmetrically substituted phthalocyanines (MPc, where M = = Cu, Co, and 2H) bearing one pyrene and six polyoxy groups as side chains. The influence of single-walled carbon nanotubes on the phase behavior of MPcs was investigated using X-ray diffraction, polarized optical microscopy and differential scanning calorimetry. It was demonstrated that the incorporation of small amounts of single-walled carbon nanotubes (≤ ≤ 1 wt.%) does not alter the MPc mesophases. The structural features and the sensor response of composite thin films of MPc with single-walled carbon nanotubes to ammonia vapor (10–50 ppm) was studied and compared with those of the films of pure MPc derivatives

Exact summation of leading infrared logarithms in 2D effective field theories

A method of exact all-order summation of leading infrared logarithms in two dimensional massless $\Phi^4$-type non-renormalizable effective field theories (EFTs) is developed. The method is applied to the ${\rm O}(N)$-symmetric EFT, which is a two-dimensional sibling of the four dimensional ${\rm O}(N+1)/{\rm O}(N)$ sigma-model. For the first time the exact all-order summation of the $\left(E^{2} \ln(1/E)\right)^n$ contributions (chiral logarithms) for the $2 \to 2$ scattering amplitudes is performed in closed analytical form. The cases when the resulting amplitudes turn to be meromorphic functions with an infinite number of poles (Landau poles) are identified. This provides the first explicit example of quasi-renormalizable field theories.Comment: 22 pages, 2 figure

Exotic and nonexotic magnetic transitions in the context of the SELEX and GRAAL experiments

We calculate magnetic transition moments in the chiral quark-soliton model, with explicit SU(3)-symmetry breaking taken into account. The dynamical model parameters are fixed by experimental data for the magnetic moments of the baryon octet and from the recent measurements of $\Theta^{+}$ mass. Known magnetic transition moments $\mu_{\Lambda\Sigma}$, $\mu_{N\Delta}$ are reproduced and predictions for other octet-decuplet and octet-antidecuplet transitions are given. In particular $\mu_{\Sigma\Sigma^{\ast}}$ recently constrained by SELEX is shown to be below $0.82 \mu_N$. The recent GRAAL data on $\eta$ photoproduction off the nucleon are explained in terms of a new narrow antidecuplet neutron-like resonance.Comment: 14 pages, 9 figures. Final version accepted for publication in Phys.Rev.

Effect of covalent and non-covalent linking of zinc(II) phthalocyanine functionalised carbon nanomaterials on the sensor response to ammonia

In this work, a comparative study of the sensor response of single walled carbon nanotubes (SWCNTs) and reduced graphene oxide (rGO) covalently and non-covalently functionalised with1-[N-(2-ethoxyethyl)-4-pentynamide]-8(11),15(18),22(25)-tris-{2-[2-(2-ethoxyethoxy) ethoxy]-1-[2-((2-ethoxy ethoxy)-ethoxy)methyl]ethyloxy}zinc(II) phthalocyanine (ZnPc) to ammonia is carried out. It was shown that in the case of SWCNT-based materials both covalent and non-covalent functionalisation with zinc(II) phthalocyanine leads to the increase of the sensor response toward NH3, while functionalisation of reduced graphene oxide causes a decrease in the response. At the same time both covalent and non-covalent linking of zinc(II) phthalocyanine leads to twofold decrease of the sensor recovery times. The sensor response of the carbon nanomaterial (single walled carbon nanotubes or reduced graphene oxide) hybrids covalently functionalised with zinc(II) phthalocyanine is several times higher than in the case of non-covalent linking of zinc(II) phthalocyanine to these nanomaterials, which is in good correlation with the number of zinc(II) phthalocyanine molecules adsorbed onto the SWCNT and rGO walls. © 2017 Elsevier B.V

Case study of ozone anomalies over northern Russia in the 2015/2016 winter: measurements and numerical modelling

Episodes of extremely low ozone columns were observed over the territory of Russia in the Arctic winter of 2015/2016 and the beginning of spring 2016. We compare total ozone columns (TOCs) from different remote sensing techniques (satellite and ground-based observations) with results of numerical modelling over the territory of the Urals and Siberia for this period. We demonstrate that the provided monitoring systems (including the new Russian Infrared Fourier Spectrometer IKFS-2) and modern three-dimensional atmospheric models can capture the observed TOC anomalies. However, the results of observations and modelling show differences of up to 20&thinsp;%–30&thinsp;% in TOC measurements. Analysis of the role of chemical and dynamical processes demonstrates that the observed short-term TOC variability is not a result of local photochemical loss initiated by heterogeneous halogen activation on particles of polar stratospheric clouds that formed under low temperatures in the mid-winter.</p

Weak electricity of the Nucleon in the Chiral Quark-Soliton Model

The induced pseudotensor constant (weak electricity) of the nucleon is calculated in the framework of the chiral quark soliton model. This quantity originates from the G-parity violation and hence is proportional to $m_u-m_d$. We obtain for $m_u-m_d=-5 MeV$ a value of $g_T/g_A =-0.0038$.Comment: The final version. Accepted for publication in Phys. Rev.

Tetrasubstituted copper phthalocyanines : correlation between liquid crystalline properties, films alignment and sensing propertie

Copper phthalocyanines (CuPc) containing alkylthio (-S(CH2)nCH3, n=7 and 15), alkyloxy- (-O(CH2)nCH3, n=7 and 15) and polyoxo (-O(CH2CH2O)3CH3 and -S(CH2CH2O)3CH3) substituents were synthesized and investigated to reveal the effects of substituents type (alkylthio, alkyloxy and polyoxo) and the type of the connecting heteroatom (oxygen or sulphur) on the mesogenic properties, films alignment and sensing behaviour. The liquid crystalline properties of these phthalocyanines were investigated by differential scanning calorimetry, polarizing optical microscopy and X-ray diffraction techniques. The structure and morphology of spun thin films of copper phthalocyanine derivatives were studied by the UV-Vis and Raman spectroscopies as well atomic force microscopy. The sensing properties of CuPc films were studied by the measurement of conductivity change upon interaction with ammonia in the range 10-50 ppm. All investigated films of CuPc derivatives display thermotropic columnar mesomorphism. It was shown that the films with polyoxo- (-O(CH2CH2O)3CH3 and -S(CH2CH2O)3CH3) substituents as well as with alkylthio -S(CH2)nCH3 (n=7) substituents, which are liquid crystalline at room temperature, form ordered films with a random planar alignment of columns. Their films exhibit the better sensor performance with the maximal sensor response for the films of CuPc containing (-S(CH2CH2O)3CH3) substituents

Blocking of lattice monopoles from the continuum in hot lattice gluodynamics

The Abelian monopoles in lattice gluodynamics are associated with continuum monopoles blocked to the lattice. This association allows to predict the lattice monopole action and density of the (squared) monopole charges from a continuum monopole model. The method is applied to the static monopoles in high temperature gluodynamics. We show that the numerical data both for the density and the action of the lattice monopoles can be described in terms of a Coulomb gas of Abelian monopoles in the continuum.Comment: 23 pages, 9 EPS figures, LaTeX2e uses JHEP3 class file; replaced to match published versio

Flavor structure of the octet magnetic moments

We use the chiral quark-soliton model to identify all symmetry breaking terms linear in $m_{s}$ and investigate the strange magnetic moment in a ``model-independent'' way. Assuming hedgehog symmetry and employing the collective quantization, we obtain the most general expression for the flavor-singlet and flavor-octet magnetic moments in terms of seven independent parameters. Having fitted these parameters to the experimental magnetic moments of the octet baryons, we show that the strange magnetic moment turns out to be positive. The best fit obtained by minimizing $\chi^2$ assuming 15% theoretical accuracy yields: $\mu^{({\rm s})}_{N} = (0.41 \pm 0.18) \mu_{N}$.Comment: 10 pages. RevTeX is used. One figure is included. The final version accepted for publication in Phys. Rev.