Active Oxygen in Oxide Catalytic Systems for Environmental Catalysis

The effect of the synthesis conditions of individual and modified with Mn Ni- and Co-oxide systems on the content and the mobility of their active oxygen has been studied by means of chemical and IR spectral analyses. The results obtained show that the main part of the active oxygen in Ni-oxide system is located on the catalyst’s surface (O_s ^* is approximately 73% of the total active oxygen), while Co-oxide system is characterized by much lower surface active oxygen content. Ni- and Co-oxide systems modified with Mn have comparatively higher active oxygen content as compared to the individual ones. Data of the IR spectral analysis reveal that Mn, as a modifying component, affects the mobility of the active oxygen, the latter contributing to the activity of oxide systems in oxidation processes. The high content of loosely bonded active oxygen formed during the synthesis determines a high catalytic activity of the studied samples in reactions of complete oxidation in the low temperature region.     

Por?se Struktur der Polyarylate

Ohne Zusammenfassung     

Thick GEM with a resistive coating

The results of testing a detector based on a thick gas electron multiplier (GEM) are presented. Impact of the TGEM dielectric charging on detector physical parameters is assessed based on simulation and experimental results. The further development of the detector—TGEM with resistive coating was constructed and tested. The test results are presented and compared to a standard thick GEM.     

Effect of Heating Procedure and Annealing Temperature on Transmission Spectra of sp1-Carbon Films Synthesized by the Ion-Plasma Method

Journal of Applied Spectroscopy - The influence of the heating procedure and annealing temperature in air on the transmission spectra and morphology of linear-chain carbon films synthesized by the...     

Extraordinary optical transmission: coupling of the Wood-Rayleigh anomaly and the Fabry-Perot resonance

In this Letter, we demonstrate for the first time that by combining the effects of the Wood-Rayleigh anomaly (WRA) and the Fabry-Perot (FP) resonance, transmission efficiencies of one-dimensional metallo-dielectric gratings on substrates can be significantly improved compared to when these two phenomena work separately. Results of combining the WRA and the FP resonance can be utilized to eliminate the necessity of using the index matching technique and the core-shell structure for enhancing the performance of extraordinary optical transmission devices. Further, the outcomes of combining the WRA and the FP resonance can elucidate some of the unexplained results in the literature.     

Analysis of lead and sulfur in environmental samples by double pulse laser induced breakdown spectroscopy

In the present work, a model of double pulse laser-induced breakdown spectroscopy (LIBS) spectrometer has been developed and results from two different applications of double pulse LIBS for solving the problems of environmental interest are presented. In one case, laser induced breakdown spectroscopy has been applied to the determination of heavy and toxic metals (lead) in soil samples. In the second case, laser induced breakdown spectroscopy was used in preliminary experiments for the detection of sulfur content in coal, and on the basis of spectral features, ways to improve the sensitivity of laser induced breakdown spectroscopy detection of sulfur are proposed. The detection limit for lead in soil was estimated to be approximately 20 ppm that is lower than the regulatory standards for the presence of lead in soil.     

Synthesis and Spectral Properties of Novel Fluorescent Poly(oxyethylene Phosphate) Tris(β-diketonate) Europium (III) Complexes

Novel poly(oxyethylene phosphate) tris(β-diketonate) europium (III) complexes have been synthesized by an improved procedure using the Atherton–Todd reaction conditions. N-ethyldiisopropylamine has been used as a mild base and propylene oxide as an acid scavenger in order to obtain poly(oxyethylene phosphate) in yield and purity higher than those achieved by conventional methods. The compounds have been characterized by ¹H, ¹³C, and ³¹P NMR and FTIR techniques. Their absorption, fluorescent excitation and emission spectra of chloroform and abs. ethanol solutions have been recorded and studied. The luminescent quantum yields and decay times have been determined and a dependence on the length of the oxyethylene spacer between phosphate groups has been established. The new polymer complexes are water soluble and have increased luminescence decay time in comparison with corresponding ternary complexes.     

Development of the Technology of Magnetron Sputtering Deposition of LiPON Films and Investigation of Their Characteristics

The results of developing the technology of magnetron sputtering deposition of a LiPON solid electrolyte and an experimental investigation of its characteristics are presented. The basic processing operations and parameters providing the formation of films of the proper morphology, structure, and elemental and phase composition are described. The data of the measurement of the physical parameters of the films by cyclic voltammetry and potentiometry are represented.     

Stability of plutonium(IV) and plutonium(VI) in nitric acid solutions under strong α-irradiation

Plutonium(IV) oxidation has been studied in 1 to 20 mol/1 HNO₃ under 1 to 14 W/1 internal alpha-irradiation and at plutonium concentrations from 2 to 100 mmol/1. Curium isotopes have been used as the basic alpha-irradiation sources. It has been established that in the systems investigated both oxidation of plutonium(IV) and reduction of plutonium(VI) take place, resulting with time in reaching the equilibrium between plutonium(IV) and plutonium(VI). The presence of plutonium(IV) enhances the reduction of plutonium(VI). The rate constants for plutonium(IV) oxidation and plutonium(VI) reduction have been estimated and their dependences upon the concentrations of nitric acid, plutonium(IV) and plutonium(VI) as well as upon the dose rate investigated. An equation has been derived which permits to calculate the concentrations of plutonium(IV) and plutonium(VI) at any desired time.     

Solvent-induced porosity in ultrathin amine plasma polymer coatings

Plasma polymers deposited from n-heptylamine onto silicon wafers have been found to form a porous microstructure when immersed in water and other solvents, with pores of dimensions and densities that vary considerably between coatings deposited under different plasma conditions. This solvent-induced pore formation was found to correlate with the observed percentage of extractable material. With low radio frequency (rf) power inputs, the resultant softer coatings possess considerably more extractable material than coatings deposited at higher applied power levels. The porosity is thus proposed to result from the formation of voids created by the extraction of soluble low-molecular-weight polymeric material, which produces shrinkage stress that the coating, firmly attached to the substrate, cannot relieve by macroscopic contraction. The microscopic contraction of plasma polymer volume creates voids that appear to span the entire film thickness. The effect of aging plasma polymers in air was also investigated. For films deposited at low power it led to reduced extraction of soluble material and different pore morphology, whereas for films deposited at higher rf power levels, the extracted amounts and pore formation were the same for aged coatings. It was also found that the density of surface amine groups was lower for films deposited under the two lowest power settings, in contrast to the commonly held belief that the use of minimal applied rf power aids retention of functional groups. These porous plasma polymer coatings with surface groups suitable for further interfacial chemical immobilization reactions may be useful for various membrane and biotechnology applications.