Materials Literature
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The excited-state complex (exciplex) formation that results from the photoinduced interaction of water-soluble cationic copper(II) 5,10,15,20-tetrakis[4-(N-methylpyridyl)]porphyrin [Cu(TMpy-P4)] with calf-thymus DNA has been studied in detail by resonance Raman (RR) spectroscopy using both ∼10 ns and ∼50 ps laser puls…
Raman spectra of the sodium salts of uridine and deoxyuridine monophosphoric acid, Na2(3′-UMP)·4H2O, Na2(5-UMP)·7H2O and Na2(5′-dUMP)·5H2O, and the cadmium salt, [Cd(5′-UMP)(H2O)2]·2H2O, were examined. Several spectral differences were observed owing to nucleoside conformational differences in the uridine residue. The…
Abstract The stability constants of several divalent first row transition and trivalent lanthanide metal complexes were determined by capillary electrophoresis (CE) methods. Four different approaches, i.e. direct formation, ligand exchange, metal exchange and metal‐ligand double exchange were developed. To verify if t…
HPLC analysis of the methanol-extractable fractions of polymers was used to study the formation of cyclic oligomers during the non-activated anionic polymerization of 6-hexanelactam initiated by sodium or magnesium salt of 6-hexanelactam and ethylmagnesium bromide at 190°C. It was demonstrated that the nature of the c…
A novel two-step method combining rubbing and UV-irradiation based on ladderlike polysilsesquioxanes (LPS) containing cinnamate and azobenzene side chains was developed to obtain alignment layers which features a high surface pretilt angle and good stability. At the first step, a low pretilt angle of 1–3° was generate…
We have performed a preliminary study by light transmission of the electro-optical behaviour of several cells prepared either from hydroxypropylcellulose (HPC) or HPC with cellulose acetate (CA) (1% w/w) cross linked in both cases with 1,4-diisobutanocianaie (BDI) (7%w/w) and different concentrations of a commercial n…
Preparation of silicon-organic films for LC alignment is described. Effect of the molecular structure of organic substituents in siloxane chains on type of LC the alignment (homeotropic, tilted, planar) is considered. Contribution of polar and dispersion parts of the surface energy of siloxane films is discussed.
Using the continuum theory the influence of the external magnetic field on the ferrocholesteric — ferronematic phase transition is analyzed. The field being applied normal to the helix. Soft homeotropic coupling between the magnetic particles and the cholesteric molecules is assumed. The diamagnetic anisotropy of the…
The method presented in this paper pertains to an optical roughness meter that considers a fabric in all surface directions. A previous paper presented a tribological method for investigating textile fabrics, which used a roughness meter with a contact between the probe and the surface. However, a contact is not alway…
Anisotropy induction in the azo-polymer introduced into microporous glass under irradiation with polarised UV light is investigated. Practically pure “angular hole burning” mechanism is realised. Influence of the porous matrix on the life-time of cis-isomers, dipol-dipol interaction of polymer side chains, main-chain…
Thermoluminescence (TL) and thermally stimulated exoelectron emission (TSEE) in calcium phosphate doped with rare earth ions, such as Dy or Tm, have been studied, because its effective atomic number is close to that of human bones and teeth. It is found that Ca3(PO4)2 doped activators show the TL and TSEE sensitivity…
tert -Butylcatechol (TBC) is an efficient inhibitor of parasitic polymerization of many monomers during their transportation and storage. Just before the monomers are used, removal of the inhibitor is often necessary and can easily be achieved by adsorption on alumina. The influence of the main physical parameters of…
New liquid crystalline materials of the general formula have been synthesized (R1, R2 are alkyl chains). Mesomorphic properties were determined using polarizing microscopy. All compounds showed very broad smectic C* phase (about 70–90 K) and the cholesteric phase. No smectic A phase was observed. In the smectic C* pha…
Treatment of [Fe(OEP)]2O with trichloroacetic acid (2.5-fold excess) results in the formation of (octaethylporphinato)(trichloroacetato)iron(III). Various crystalline solvates can be isolated, depending on the crystallization solvent. Initial crystallization with CHCl3/hexanes resulted in the isolation of a monoclinic…
Five new polyamideimides (PAI) were synthesized from five diacid chlorides with preformed imide rings and a telechelic α,ω-diamino-polyoxyethylene (Jeffamine JFA ED600). The diacid chloride monomers could be obtained in high yields (77–92%) from chlorinating the corresponding diacids which were obtained from the react…
The synthesis and properties of a new mesogenic/nonmesogenic copolymer system, namely the poly[6-(4′-methoxyazobenzene-4′-oxy)hexyl methacrylate]-co-poly[methyl methacrylate]s, are described. Copolymers containing 0.59 or greater mol fraction of the mesogenic side-groups exhibit nematic behaviour while those containin…
Nowadays, a modern physical theory becomes of a principle importance in understanding the complexities of the living world: the physics of lyotropic states of matter. We demonstrate here what kind of specification is necessary in the molecular description of lyomesogens, in the theory of elastic and flexoelectric phen…
High‐temperature (1200–1550 K) mechanical‐loss and shear‐modulus measurements were performed on fine‐grained magnesia‐ and magnesia/ytrria‐doped alumina at low frequency (10 −4 −10 1 Hz), using a forced‐vibration torsion pendulum. Anelastic and viscoplastic relaxation phenomena were observed, which may be associated w…
A new, high sensitive, thermoluminescent material SrSO4:Mo, Tb is reported. TL sensitivity is three times that of widely used CaSO4:Dy. Emission of the phosphor is in the near UV-blue region of the spectrum which falls in the most sensitive region of the common photomultiplier tubes. In addition to this, good linearit…
A new calorimeter is constructed to precisely measure the heat of wetting of cotton, regular viscose rayon, high wet strength viscose rayon, and Tencel®. Our purpose is to investigate the relationship between the heat of wetting and structural characteristics of fibers such as crystal and fiber structure, degree of cr…