Structure and reflective properties of Al-Cu-Fe quasicrystalline thin film prepared by laser induced arc method

Al-Cu-Fe thin films were prepared by laser induced arc (laser-arc) method from a single source-Al63Cu25Fe12 alloy, which was proved to consist of quasicrystalline phase together with approximant phase. The composition of the deposited films meets the requirement for formation of icosahedral symmetry phase. Quasicrystalline phase was obtained after annealing the amorphous as-deposit film samples. The optical properties of the samples were investigated. Thin film samples of Al, Cu and Fe deposited under the same condition were employed for comparison. The results showed specific reflective properties of Al-Cu-Fe quasicrystal thin film in some wavelength range. The optical conductivity of the films exhibited a negative peak, centered about 440 nm in range of 190to 800 nm. The Al-Cu-Fe quasicrystal thin films could absorb almost all the ray in the wavelength range from 420nm to 450 nm. The ratio of absorption was greater than 99%.     

THE PREPARATION AND STABILITY OF COLLOIDAL METAL DISPERSIONS PREPARED BY A TWO-PHASE NON-AQUEOUS ROUTE

Stable suspensions of small metal Au, Ru, PI, Pd, Rh, Co and Nl particles dispersed in n-heptane and n-dodecane have been prepared using a novel two-phase system, Involving the formation of the particles In a methanolic phase and subsequent phase transfer of the panicles to the alkane medium. The dispersions consisted of small particles having diameters In the range of 8-30 nm (the gold sols were very polydlsperse having average diameters of ca.34 nm). The phase transfer of the particles and their subsequent colloid stability were effected by the presence of dissolved dispersant in the hydrocarbon phase (either Oloa 1200 or Hypermer LP 8). In the case of Oloa 1200, a widely-used polylsobutylene succinimide automotive engine dispersant, It Is proposed that the amlne groups adsorb strongly to the acidic surface o1 the particles, and the 70-carbon polyisobutylene chains extend Into the hydrocarbon medium sufficiently to maintain the separation of adjacent particles by steric and possibly also by electrical repulsion.     

Analysis of red and yellow ochre samples from Clearwell Caves and Catalhöyük by vibrational spectroscopy and other techniques

Ochre samples excavated from the neolithic site at Catalh?yük, Turkey have been compared with "native" ochres from Clearwell Caves, UK using infrared spectroscopy backed up by Raman spectroscopy, scanning electron microscopy (with energy-dispersive X-rays (EDX) analysis), powder X-ray diffraction, diffuse reflection UV-Vis and atomic absorption spectroscopies. For the Clearwell Caves ochres, which range in colour from yellow-orange to red-brown, it is shown that the colour is related to the nature of the chromophore present and not to any differences in particle size. The darker red ochres contain predominantly haematite while the yellow ochre contains only goethite. The ochres from Catalh?yük contain only about one-twentieth of the levels of iron found in the Clearwell Caves ochres. The iron oxide pigment (haematite in all cases studied here) has been mixed with a soft lime plaster which also contains calcite and silicate (clay) minerals.     

Analysis of B6 vitamers in plasma by reversed-phase column liquid chromatography

The seven vitameric forms of B6 can be measured in biologic fluids by high-performance liquid chromatography. Use of a reversed-phase column, with optimized solvent and buffer conditions, combined with fluorometric detection, allowed linear detection of vitamers from 0.4 to 20 ng. All vitamers from plasma, urine or tissue extracts can be analyzed within 50 min. Reproducibility and recovery studies indicate a selective and sensitive procedure, which greatly enhances studies on vitamin B6 metabolism.     

A simple synthesis of 1-phenothiazineethanolamines: Potential antimalarials

Two routes for the synthesis of the 1-phenothiazineethanolamine (4) starting from 1,2-dioxo-1,2-dihydropyrrolo[3,2,1-kl]phenothiazine are described.     

Chemistry of the phenoxathiins and isosterically related heterocycles. XIV. Total assignment of the 13C-Nmr spectrum of pyrrolo[3,2,1-kl]phenothiazine

Total assignment of the ¹³C-nmr spectrum of the novel tetracyclic phenothiazine, pyrrolo[3,2,1-kl]phenothiazine is described. Assignments were determined from model systems, ¹H-¹³C spin-coupling behavior in conjunction with selective excitation techniques and spin-lattice (T₁) relaxation measurements. The anisotropic reorientation of this ring system via a principal axis passing through the center of the molecule, which provides a qualitative basis for signal discrimination, is also discussed.