Analysis of siliceous materials and coal by atomic absorption spectrophotometry with fusion for sample decomposition

The oxalic acid-lithium carbonate-lithium tetraborate (1:1:1) fusion agent proposed previously for cement analysis is applied to determine the composition of various siliceous samples including granite, clay, flyash, sand and silica fume. For samples with silica content higher than 70%, the sample size had to be reduced from 0.10 to 0.01 g and a recovery factor was needed in silica determination to account for the precipitation of silica during acid dissolution. Attempt has also been made to determine the major metallic elements in coal by fusion directly without the ashing procedure, and the results obtained were good. Further, the ash content of coal was proposed to be determined by establishing a relation between the ash content and the sum of the concentrations of four major oxides (i.e. the oxides of Si, Al, Fe and Ca), and the proposed method is accurate and is time saving compared with that determined by direct ashing at 800 degrees C.     

Anti-fouling chemistry of chiral monolayers: enhancing biofilm resistance on racemic surface

This work reports the resistance to protein adsorption and bacterial biofilm formation by chiral monolayers of polyol-terminated alkanethiols surrounding micrometer-sized patterns of methyl-terminated alkanethiols on gold films. We discover that patterned surfaces surrounded by chiral polyol monolayers can distinguish different stages of biofilm formation. After inoculation on the surfaces, bacteria first reversibly attached on the chiral polyol monolayers. Over time, the bacteria detached from the polyol surfaces, and attached on the hydrophobic micropatterns to form biofilms. Interestingly, while both enantiomers of gulitol- and mannonamide-terminated monolayer resisted adsorption of proteins (bovine serum albumin, lysozyme, and fibrinogen) and confined biofilms formed on the micropatterns, the monolayers formed by the racemic mixture of either pair of enantiomers exhibited stronger antifouling chemistry against both protein adsorption and biofilm formation than monolayers formed by one enantiomer alone. These results reveal the different chemistries that separate the different stages of biofilm formation, and the stereochemical influence on resisting biofoulings at a molecular-level.     

Photolysis of copolymers 4-methoxyacrylophenone with 2-hydroxy-4-(2-methacroyloxyethoxy) benzophenone

The photolysis of copolymers of 4-methoxyacrylophenone with 2-hydroxy-4-(2-methacroyloxyethoxy) benzophenone (4MAP/PBMA) containing 0–8 wt/wt 2% of BPMA was compared with that of poly-4-methoxyacrylophenone (P4MAP) in the presence of 2-hydroxy-4-(2-isobutyroyloxyethoxy) benzophenone (BPIB) in ethyl benzoate at 366 nm. In the photolysis of P4MAP proceeding through the long-lived triplet state, it was possible to separate quenching and screening effects of BPIB. The dependence of the ratio of quantum yields of main chain scission without and with quencher was linear for free quencher; for copolymerized quencher, however, the dependence indicated static quenching. Using the Perrin model for copolymers, the quenching sphere of 1.56 nm was calculated. Study of the emission decay of copolymers 4MAP/BPMA in poly(methyl methacrylate) films at 77 K give 1.86 nm for the quenching sphere. Similar values were found for quenching of 4-methoxyacrylophenone chromophore by built-in acceptors naphthalene and diphenyl (1.60 nm). These results indicate that energy transfer in carbonyl copolymers, both in dilute solution and in film, at 77 K proceeds at a distance a little greater than the sum of donor and acceptor diameters (about 1.2 nm) showing that the extent of triplet energy migration is limited.     

Extended number state basis and number-phase intelligent states of light field II. The reduced number-sine intelligent and Jackiw states

The number-sine intelligent state is introduced for the extended Hilbert space and reduced to serve as an approximation to the Jackiw number-sine intelligent state. Usual and modified statistical and uncertainty characteristics of these states are determined and compared. A new technique is used for reconstructing the crescent state of Kitagawa and Yamamoto and studying the properties of the reduced number-sine intelligent state.     

Polyelectrolyte complex membranes – surface and permeability properties

In order to study, how the membrane hydrophilicity influences the pervaporation (PV) separation properties in dehydration of alcohols, two polyelectrolyte complex (PELC) membranes, based on interfacial reaction of polyanionic sodium salt of sulfoethyl cellulose (SEC) with polycationic poly[dimethyl(diallyl)ammonium chloride] (pDMDAAC), or cationic surfactant benzyl(dodecyl)dimethylammonium chloride (BDDDMAC), were prepared and tested. Contact angle measurements on membrane surfaces made in various media showed that the membrane hydrophilicity, in the sense of water wettability, had not influence neither to flux nor selectivity in the PV dehydration process. On the contrary, the membrane wettability determined by contact angle measurements in the real water/alcohol separation mixture, correlated very well with the PV experiments. These findings are confronted with the solution-diffusion PV model.