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Sol-Gel Synthesis and Super conducting Properties of Bi-2212 High-TC Super conductors

Zalga A., Beganskiene A., Kareiva A.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 9

1547-1553

EN

A novel aqueous sol-gel synthesis technique has been refined to prepare heterometallic (Bi1.75Pb0.25)Sr2CaCu2Ox and (Bi1.8Pb0.33)Sr1.87CaCu2Ox (Bi-2212) oxides. The formation of Bi-2212 phase depending on synthesis conditions (duration of annealing, stoichiometry of metals) has been estimated. The synthesized products were characterized by powder X-ray diffraction analysis (XRD) and resistivity measurements. It was demonstrated, that the investigated synthesis conditions only slightly influence on the phase purity and super conducting properties of Bi-2212 phase.

2

Sol-gel preparation and characterization of perovskite gadolinium aluminates

Cizauskaite S., Reichlova V., Nenartaviciene G., Beganskiene A., Pinkas J., Kareiva A.

Materials Science Poland

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2007

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Vol. 25, No. 3

755--765

EN

The paper reports on the results concerning the sol-gel preparation of the nanocrystalline nonsubstituted and Sr-substituted gadolinium aluminate (GdAlO3, GAP) ceramics at slightly varying conditions of synthesis. The metal ions, generated by dissolving starting materials of metals in the diluted acetic acid were complexed by 1,2-ethanediol to obtain precursors for the non-substituted and Sr-substituted GAP. In the sol-gel processing different starting gadolinium materials such as gadolinium nitrate or gadolinium oxide were employed. The influence of the temperature and the amount of substituent on the phase purity of GAP was also investigated. Phase transformations, composition and micro-structural features in the gels and polycrystalline samples were studied by thermal analysis, powder X-ray diffraction analysis, infrared spectroscopy and scanning electron microscopy.

3

Sol-gel derived antireflective coating with controlled thickness and reflective index

Beganskiene A., Sakirzanovas S., Kazadojev I., Melninkaitis A., Sirutkaitis V., Kareiva A.

Materials Science Poland

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2007

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Vol. 25, No. 3

817--824

EN

Optical properties and structure of antireflective coatings (AR) deposited from hydrolysed TEOS sol have been characterized in detail. The influence of various parameters on the formation of colloidal silica antireflective coatings by the dip-coating technique has been investigated. For the characterization of colloidal silica films, the UV-visible spectroscopy, laser ellipsometry, and atomic force microscopy were used. Using optimal sol-gel processing conditions (dipping rate - 40 mm/min, coating time - 20 s, and temperature - 20 oC), the colloidal silica coatings were obtained and characterized in comparison with non-coated glass substrate. The reflectance of AR coatings increased with increasing the temperature of sol-gel processing. The laser damage threshold of as deposited films was measured at 1064 nm (1H) and 335 nm (3H) wavelength using a Nd:YAG lasers. The laser damage threshold of AR coating exceeded 15.22 J/cm2 at 1064 nm and 26.82 J/cm2 at 355nm.

4

Destructive Effects of Paper Conservation Procedure on the Writing Iron Gall Ink-Evidence from Transmetalation Reaction

Senvaitiene J., Pakutinskiene I., Beganskiene A., Tautkus S., Kazlauskas R., Kareiva A.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 10

1575-1583

EN

The influence of carboxylate-alumoxane protective coatings on the condition of writing paper inked with iron and copper gall inks has been investigated. All paper samples used in this study were coated with hexanato-alumoxane at room temperature changing the soaking time from 1 to 8 h. The influence of deconservation parameters (duration and temperature) on the stability of inks was also studied. Paper samples (untreated, coated and after deconservation) were examined by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Analytical characterization of paper samples showed no degradation of its cellulosic substrate during conservation. However, the destructive effect of alumoxane on the writing iron gall inks was determined.

5

Interaction of Heavy Metals with Envelopes of Sensitive and Resistant Gram-negative Bacteria

Dervinyte M., Bakiene E., Beganskiene A., Rubikas J., Daugelavicius R.

Chemia i Inżynieria Ekologiczna

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2002

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Vol. 9, nr 8

869-884

EN

Interaction ofNi2+ and Cd2+with the envelopes of E. coli and S. typhimurium cells, which exhibit different sensitivity to heavy metals, was examined. The cation binding capacity of S. typhimurium cells depended on the concentration of metal ions and correlated with the length of polysaccharide chains in bacteria lipopolysaccharide. Heating-killed cells of E. coli bound more Ni2+ than intact, actively metabolizing ones. The acidification of bacteria surface did not diminish the affinity of cell envelopes to Cd2+. In the course of transient treatment, a 20 mM solution of Ni2+ exhibited bactericidal effect only on the sensitive E. coli JMIOI cells taken from the exponential growth phase and suspended in Tris/HCI medium. Both Ni2+ and Cd2+ diminished the voltage of cell plasma membrane (PM), but Cd2+ induced stronger depolarisation than Ni2+ did. At concentrations above 1 mM, Cd2+ inhibited the cell respiration and was bactericidal to all strains tested. At the concentration of 5 mM, Ni2+ increased the PM permeability, while at concentrations higher than 20 mM it noticeably inhibited the respiration of E. coli JMIOI, S. typhimurium 0588 and SLlI02 cells. The depolarising activity of Ni2+ did not correlate with its bactericidal action - the Ni2+ resistant E. coli V38 strain survived a temporary treatment with Ni2+ in spite of changes in the PM permeability.

PL

Badano oddziaływanie Ni2+ i Cd2+ na błony komórek E. coli i S. typhimurium, wykazujących odmienną wrażliwość na metale ciężkie. Zdolność wiązania kationów w komórkach S. typhimunum zależała od koncentracji jonów i korelowała z długością łańcucha polisacharydowcgo bakteryjnego lipopolisacharydu. Komórki E. coli, termicznie uśmiercone wiązały więcej Ni2+ niż zwykłe komórki metabolicznie aktywne. Acydyfikacja powierzchni bakterii nie zmniejszała ich powinowactwa błony bakteryjnej do Cd2+. W wypadku krótkotrwałej obróbki 20 mM roztwór Ni2+ wykazywał działanie bakteriobójcze tylko w względem wrażliwych E. coli JMlOl w fazie ich wzrostu eksponencjalnego, gdy były one zanurzone w roztworze Tris/HCI. Zarówno Ni2+, jak i Cd2+ zmniejszały napięcie na membranie plazmatycznej (MP), jednak jony Cd2+ bardziej ją depolaryzowały niż jony Ni2+. przy koncentracjach większych niż l mM, Cd2+ hamowały oddychanie komórki i działały bakteriobójczo na wszystkie badane szczepy. Koncentracja 5 mM Ne+ powiększała przenikalność MP, natomiast koncentracja powyżej 20 mM zauważalnie hamowała oddychanie E. coli JMIOl, S. typhimunum DS88 oraz SL1102. Aktywność depolaryzacyjna, wykazywana przez Ni2+ nie korelowała z ich działaniem bakteriobójczym. Oporne na działanie Ni2+ szczepy E. coli V38 nie ginęły pod wpływem krótkotrwałej obróbki za pomocą roztworu Ni2+, chociaż przy tym zachodziły zmiany przenikalności PM.