Ionization constants and thermal stabilities of uracil and adenine under hydrothermal conditions as measured by in situ UV–visible spectroscopy

2012 ◽  
Vol 93 ◽  
pp. 182-204 ◽  
Author(s):  
Erik Balodis ◽  
Melerin Madekufamba ◽  
Liliana N. Trevani ◽  
Peter R. Tremaine
Keyword(s):  
Ionization Constants ◽  
Visible Spectroscopy ◽  
Hydrothermal Conditions ◽  
Thermal Stabilities ◽  
Uv Visible

In Situ Polymerization and Characterization of Poly(ε-caprolactone)/Layered Double Hydroxide Nanocomposites

2012 ◽  
Vol 557-559 ◽  
pp. 371-374
Author(s):  
Lian Liu ◽  
Teng Yu ◽  
Pei Wang ◽  
Guang Shuo Wang
Keyword(s):  
Layered Double Hydroxide ◽  
In Situ Polymerization ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Uv Visible ◽  
Absorbance Peak ◽  
Double Hydroxide

Nanocomposites of poly(ε-caprolactone) (PCL) and layered double hydroxide (LDH) were prepared by in situ polymerization at low LDHs loadings in this work. The resultants were characterized by FTIR spectroscopy, X-ray diffraction (XRD), differential scanning calorimeter (DSC) and UV-visible spectroscopy (UV-vis). FTIR showed that the PCL/LDHs nanocomposites were prepared successfully by in situ polymerization and XRD spectra showed that the crystal structure did not change greatly in the presence of LDHS. DSC results confirmed that LDHs could act as nucleating agents. UV-vis spectra showed that LDHs had stronger absorbance peak than LDH. Moreover, the PCL/LDHs nanocomposites had strong anti-ultraviolet effect by introduction of LDHs into polymer matrix.

scholarly journals Extent of Reduction of Vanadium Oxides during Catalytic Oxidation of Alkanes Measured by in-Situ UV−Visible Spectroscopy

2004 ◽  
Vol 108 (7) ◽  
pp. 2345-2353 ◽  
Author(s):  
Morris D. Argyle ◽  
Kaidong Chen ◽  
Carlo Resini ◽  
Catherine Krebs ◽  
Alexis T. Bell ◽  
...  
Keyword(s):  
Catalytic Oxidation ◽  
Vanadium Oxides ◽  
Visible Spectroscopy ◽  
Uv Visible

scholarly journals Silver/poly(N-vinyl-2-pyrrolidone) nanocomposites obtained by the electrochemical synthesis

2011 ◽  
Vol 65 (6) ◽  
pp. 687-696 ◽  
Author(s):  
Zeljka Jovanovic ◽  
Aleksandra Radosavljevic ◽  
Zorica Kacarevic-Popovic ◽  
Vesna Miskovic-Stankovic
Keyword(s):  
Applied Voltage ◽  
Ag Nanoparticles ◽  
Silver Ions ◽  
Mie Scattering ◽  
Visible Spectroscopy ◽  
Vis Spectroscopy ◽  
Theoretical Predictions ◽  
Implementation Time ◽  
Uv Visible

Silver/poly(N-vinyl-2-pyrrolidone) (Ag/PVP) nanocomposites were obtained by electrochemical reduction of Ag+ ions at a constant voltage, by the in situ synthesis of silver nanoparticles inside poly(N-vinyl-2-pyrrolidone) matrix, previously crosslinked by ?-irradiation. Optimal values of synthesis parameters were investigated: the composition of the solution for swelling of PVP hydrogel, implementation time and applied voltage. Ag/PVP nanocomposites were characterized by UV-visible spectroscopy, and IR spectroscopy. UV-visible spectroscopy results shown that the reduction of silver ions was more efficient when the more conductive solution for swelling of PVP hydrogel was used, i.e. the solution containing 3.9 mM AgNO3 with 0.1 M KNO3. Also, it was shown that the concentration of the reduced silver increases with the increase in implementation time and applied voltage, up to the values of 4 min, and 200 V, respectively. The Ag nanoparticle size was estimated to be 25 nm, by comparison of the experimental results of UV-vis spectroscopy with the theoretical predictions obtained by the calculations in ?MiePlot v.3.4? computer program, having the algorithm based on Mie scattering from a sphere. The results of FTIR spectroscopy have shown that Ag nanoparticles are mainly bonded to PVP by coordination bondages between Ag nanoparticles and N from the pyrrolidone ring of PVP.

scholarly journals Polyaniline In Situ Grafted to Graphene Sheets

KIMIKA ◽  
2014 ◽  
Vol 25 (2) ◽  
pp. 23-35 ◽  
Author(s):  
Elliard Roswell S. Yanza ◽  
Geoffrey Matthew C. Tan ◽  
Christine Joy U. Querebillo ◽  
Armando S. Somintac ◽  
Arnel A. Salvador ◽  
...  
Keyword(s):  
Graft Polymerization ◽  
Diazonium Salts ◽  
Oxidizing Agent ◽  
Visible Spectroscopy ◽  
Ammonium Peroxydisulfate ◽  
Exfoliated Graphene ◽  
Chemical Grafting ◽  
Uv Visible ◽  
Modified Graphene

Graphene is one of the most promising allotropes of carbon with wide applications in nanotechnology. Modification of graphene by chemical means can further expand its uses. Here, liquid-exfoliated graphene is functionalized with p-aminophenyl moiety using p-nitrophenyl diazonium salts which were diazotized in situ then reduced by tin(II) chloride. The aminophenyl-graphene thus produced is further modified to form polyaniline-graphene (PANI-GNH) by in situ oxidative graft polymerization of aniline using ammonium peroxydisulfate as oxidizing agent. The properties of the PANI-GNH were compared with polyaniline/graphene blends by Raman, infrared and UV-Visible spectroscopy, and cyclic voltammetry. Indeed, PANI-GNH registered different spectrochemical and electrochemical properties compared with the physically blended PANI and GNH, a manifestation of the effect of chemical grafting on the overall property of the modified graphene.

scholarly journals Ionization constants of aqueous amino acids at temperatures up to 250°C using hydrothermal pH indicators and UV-visible spectroscopy: Glycine, α-alanine, and proline

2005 ◽  
Vol 69 (12) ◽  
pp. 3029-3043 ◽  
Author(s):  
Rodney G.F. Clarke ◽  
Christopher M. Collins ◽  
Jenene C. Roberts ◽  
Liliana N. Trevani ◽  
Richard J. Bartholomew ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ionization Constants ◽  
Visible Spectroscopy ◽  
Ph Indicators ◽  
Uv Visible
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