bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of doping with CeO2 and calcination temperature on physicochemical properties of the NiO/Al2O3 system
Authors: Shaheen Waleed , El-Hendawy A. 
Published: October 2009

Abstract
The effects of doping with CeO2 and calcination temperature on the physicochemical properties of the NiO/Al2O3 system have been investigated using DTA, XRD, nitrogen adsorption measurements at −196°C and decomposition of H2O2 at 30–50°C. The pure and variously doped solids were subjected to heat treatment at 300, 400, 700, 900 and 1000°C. The results revealed that the specific surface areas increased with increasing calcination temperature from 300 to 400°C and with doping of the system with CeO2. The pure and variously doped solids calcined at 300 and 400°C consisted of poorly crystalline NiO dispersed on γ-Al2O3. Heating at 700°C resulted in formation of well crystalline NiO and γ-Al2O3 phases beside CeO2 for the doped solids. Crystalline NiAl2O4 phase was formed starting from 900°C. The degree of crystallinity of NiAl2O4 increased with increasing the calcination temperature from 900 to 1000°C. An opposite effect was observed upon doping with CeO2. The NiO/Al2O3 system calcined at 300 and 400°C has catalytic activity higher than individual NiO obtained at the same calcination temperatures. The catalytic activity of NiO/Al2O3 system increased, progressively, with increasing the amount of CeO2 dopant and decreased with increasing the calcination temperature.
Synthesis of hydroxyapatite by using calcium carbonate and phosphoric acid in various water-ethanol solvent systems
Authors: Engin Arzu , Girgin İsmail 
Published: October 2009

Abstract
The purpose of the present study is to synthesize hydroxyapatite by using CaCO3 and H3PO4 in various water-ethanol solvent systems. It was observed from experiments that formation of ammonium phosphate compounds hindered the formation of calcium phosphates in ethanol medium. Although the reactivity was better in aqueous medium, the carbonate contents of the products obtained were above 8.5%. Best results with a carbonate content as low as 3.82% was obtained in 50% ethanol containing mixed-aqueous medium at 80°C and the FTIR analysis showed that the product was a carbonated apatite with a calculated composition of 14CaO·4.2P2O5·CO3·7.2H2O. The amorphous and porous phosphate compound obtained with a BET surface area of 106.6 m2 g−1 seems to be useful as adsorbent in wastewater treatment. Upon sintering of the amorphous product at 750°C, crystalline hydroxyapatite with a BET surface area of 25.9 m2 g−1 is obtained that may be used in biomedical applications.
Miniaturization of flow-through generation cells for electrochemical hydride generation in AAS
Authors: Hraníček J. , Červený V. , Rychlovský P. 
Published: October 2009

Abstract
The construction and optimization of five new types of miniaturized flow-through electrolytic cells with lead cathode and platinum anode for electrochemical hydride generation in atomic absorption spectrometry (HG-QFAAS) were achieved during this research study. The ion-exchange membrane was not part of these cells and only one carrying electrolyte for both electrode chambers was used. Hydride generation efficiency achieved was either comparable or higher than the one recorded for the classic thin-layer generation cell. The inner volume of the cathode chamber was reduced to a quarter of the classic thin-layer flow-through cell. Compared to the commonly used thin-layer flow-through cell, higher sensitivity (7.32×103 dm3 µg−1) and better limit of detection (0.32 µg dm−3) were obtained for selenium determination using two of these new generators.
Activity and kinetics studies of yeast alcohol dehydrogenase in a reverse micelle formulated from functional surfactants
Authors: Zhang Yun , Huang Xirong , Ji Guanglei , Li Ying , Liu Weifeng , Qu Yinbo 
Published: October 2009

Abstract
Yeast alcohol dehydrogenase (YADH) showed substantial decrease in its catalytic activity due to the strong electrostatic interaction between the head groups of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) and YADH in AOT reverse micelles. However, the catalytic activity of YADH in a nonionic reverse micellar interface (GGDE/TX-100) obtained from a functional nonionic surfactant N-gluconyl glutamic acid didecyl ester (GGDE) and Triton X-100 (TX-100) was higher than that in AOT reverse micelle under the respective optimum conditions. A comparison of the kinetic parameters showed that the turnover number kcat in GGDE/TX-100 reverse micelle was 1.4 times as large as that in AOT reverse micelle, but the Michaelis constants in AOT reverse micelle for ethanol K mB was twice and for coenzyme NAD+ K mA was 5 times higher than their counterparts in GGDE/TX-100 reverse micelle. For the conversion of ethanol, the smaller K mB and larger kcat in GGDE/TX-100 reverse micelle resulted in higher catalytic efficiency kcat/K mB. The stability of YADH in GGDE/TX-100 reverse micelle was also found to be better than that in AOT reverse micelle. They were mainly attributed to the absence of electric charge on the head groups of GGDE and TX-100 in the GGDE/TX-100 reverse micelle.
Synthesis of novel mesoporous Al2O3 microspheres with flower-like structure
Authors: Liu Huiping , Lu Guanzhong , Guo Yun , Wang Yanqin , Guo Yanglong 
Published: October 2009

Abstract
Using glucose as a structuring additive and aluminium nitrate as the Al precursor, a novel kind of mesoporous Al2O3 microspheres with flower-like structure were synthesized hydrothermally at 180°C for 20 h. When the synthesis temperature was lowered to 140°C, the carambola-like Al2O3 can be synthesized. This approach is convenient and simple, and flower-like Ce-Al2O3 and La-Al2O3 spheres have also been prepared in this way. It may be applied to synthesize other metal oxides when suitable precursor salts are used. From an analysis of the experimental results, a mechanism for the formation of the flower-like Al2O3 spheres has been proposed and discussed.
Investigation of electrical properties of PANI/chalcogenide junctions
Authors: Shaktawat Vinodini , Patidar Dinesh , Sharma Kananbala , Saxena Narendra , Sharma Thansewar. 
Published: October 2009

Abstract
Pure Polyaniline (EB) and Polyaniline doped with different protonic acids (ESs) were chemically synthesized using ammonium peroxydisulphate (APS) as an oxidant. Junctions have been prepared by evaporating chalcogenide materials (ZnSe, CdSe) on conducting polyaniline (EB &amp; ESs) pellets using a vacuum evaporation technique. I–V characteristics of junctions have been studied at room temperature using the Keithley electrometer 6517A. I–V measurements show the rectification effect. A junction of ES[PO43−] may be preferred over the other junctions due to its low ideality factor and maximum rectification ratio.
Use of the sulfide minerals pyrite and chalcopyrite as electrochemical sensors in non-aqueous solutions. The potentiometric titration of weak acids in alcohols
Authors: Mihajlović Ljiljana , Nikolić-Mandić Snežana , Vukanović Branislav , Mihajlović Ranđel 
Published: October 2009

Abstract
Natural monocrystalline pyrite and chalcopyrite were examined as new indicator electrodes for the potentiometric titration of weak acids in tert-butanol and iso-propanol. The electrodes investigated demonstrated a linear dynamic response for p-toluenesulfonic acid concentrations in the range from 0.1 to 0.001 M, with a Nernstian slope of 48 mV per decade for pyrite in tert-butanol. Sodium methylate, potassium hydroxide and tetrabutylammonium hydroxide (TBAH) proved to be suitable titrating agents. The response time was less than 12 s and the lifetime of the electrodes was higher than 1 year. The advantages of the electrodes are long-term stability, rapid response, reproducibility, easy preparation and low cost.
Polarized light spectroscopy of azobenzene or disperse red 1 with Mn12 single-molecule magnets in PMMA film hybrid materials
Authors: Akitsu Takashiro , Ishioka Chiaki , Itoh Tsubasa 
Published: October 2009

Abstract
A series of organic/inorganic hybrid materials containing the single-molecule magnet [Mn12(CH3COO)16(H2O)4O12]·2CH3COOH·4H2O with the photochromic compounds azobenzene or disperse red 1 cast into polymethyl methacrylate films was prepared. To understand the photomodulation of analogous mixtures’ AC susceptibility, we investigated the molecular alignment based on Weigert’s effect accompanying cycles of cis-trans photoisomerization by alternate irradiations with polarized UV and visible light. Polarized electronic spectra of the hybrid materials demonstrated gradually increasing anisotropy. These features suggest interactions between photochromic compounds and the Mn12 complex in polymethyl methacrylate.
Cloud point extraction-preconcentration and flame atomic absorption spectrometric determination of low levels of zinc in water and blood serum samples
Authors: Shokrollahi Ardeshir , Shamsipur Mojtaba , Jalali Fahimeh , Nomani Hamid 
Published: October 2009

Abstract
A simple, sensitive and selective flotation method is described for the preconcentration and atomic absorption spectrometric determination of zinc ion in water and blood samples. At a solution pH of 5.2, 4-(2-pyridylazo-resorcinol) and Triton X-114 were used as hydrophobic ligand and non-ionic surfactant, respectively. The chemical variables affecting the preconcentration process were optimized. Under the optimized experimental conditions, the selective preconcentration and determination of as low zinc concentration as 6.5 µg L−1 can be made. The proposed method was successfully applied to the preconcentration and low-level determination of zinc in different water and blood serum samples.
Acid-base behaviour of sanguinarine and dihydrosanguinarine
Authors: Absolínová Helena , Jančář Luděk , Jančářová Irena , Vičar Jaroslav , Kubáň Vlastimil 
Published: October 2009

Abstract
Acid-base and optical properties of sanguinarine and dihydrosanguinarine were studied in the presence of HCl, HNO3, H2SO4, H3PO4, CAPSO and acetic acid (HAc) of different concentrations and their mixtures. The equilibrium constants pKR+ of the transition reaction between an iminium cation Q+ of sanguinarine and its uncharged QOH (pseudo-base, 6-hydroxy-dihydroderivative) form were calculated. A numerical interpretation of the A-pH curves by a SQUAD-G computer program was used. Remarkable shifts of formation parts of absorbance-pH (A-pH) curves to alkaline medium were observed. The shifts depend on the type and concentration of inert electrolyte (the most remarkable for HNO3 and HCl). The corresponding pKR+ values ranged from 7.21 to 8.16 in the same manner (ΔpKR+ = 0.81 and 0.73 for HNO3 and HCl, respectively). The priority effect of ionic species and ionic strength was confirmed in the presence of NaCl and KCl. The strength of interaction of SA with bioactive compounds (i.e. receptors, transport proteins, nucleic acids etc.) may be affected because of the observed influence of both cations and anions of the inert electrolytes.
Modified silica surface by phenylboronic acid derivatives as effective sugar sensor
Authors: Kurczewska Joanna , Schroeder Grzegorz 
Published: October 2009

Abstract
Silica surface was modified with phenylboronic acid derivatives. The structures of the functionalized supports were characterized by FT-IR spectroscopy, 13C CP/MAS NMR spectrometry, elemental and thermogravimetric analysis. The solid supports were effectively applied as artificial receptors for sugars in aqueous solutions. Alizarin Red S. (ARS) was used to detect colour change upon carbohydrate (sugar) binding. The association constants of the supports studied-ARS complex and the functionalized silica-sugar (glucose) complex were calculated. The parameters obtained were comparable with those for the phenylboronic acids used for the silica gel modification. The competitive binding of the functionalized silica surface with ARS and sugar were studied by UV/VIS measurements.
“Bubble Bunch” phenomenon in operation of a bubble column
Authors: Bastani Dariush , Baghaei Ali , Sarrafi Amir 
Published: October 2009

Abstract
While studying the operation of a rectangular bubble column in laboratory scale, it was observed that under certain circumstances tiny bubbles attach to larger bubbles without causing them to coalesce. In other words, bubbles with large diameters (d &gt; 5 mm) swept tiny bubbles (d
High surface area nano-sized La0.6Ca0.4MnO3 perovskite powder prepared by low temperature pyrolysis of a modified citrate gel
Authors: Soleymani Meysam , Moheb Ahmad , Joudaki Ezatolah 
Published: October 2009

Abstract
Single phase nanocrystalline La0.6Ca0.4MnO3 powder was synthesized by both the usual and a modified citrate gel precursor method, and the effects on the formation of homogeneous nano-sized powder with a perovskite structure were investigated. In the modified method, single phase La0.6Ca0.4MnO3 powder with an average particle size of 17.2 nm was obtained when the powder was pyrolyzed at 520°C for 2 h. Its specific surface area was 40.7 m2 g−1, about 4-fold larger than that of powder made by the usual citrate gel method.
Temperature-induced phase transition; Polymorphism in BP2 SAMs on Au(111)
Authors: Azzam Waleed 
Published: October 2009

Abstract
Self-assembled monolayers (SAMs) of ω-(4′-methylbiphenyl-4-yl)ethanethiol (CH3(C6H4)2(CH2)2SH, BP2) prepared at different temperatures on Au(111) substrates were investigated using scanning tunneling microscopy (STM). Also, the effect of the incubation time of the gold substrate in the thiol solution was examined. The STM results showed that samples prepared at room temperature were significantly different from those prepared at elevated temperatures in their surface morphology, space group and size of unit cell. The micrographs of samples prepared at higher temperatures revealed a pronounced and progressive increase in the size of the well-known etch-pits at the expense of their density with increasing preparation temperature (but the increase did not continue for SAMs prepared at 348 K). The average domain size was found to increase significantly with increasing preparation temperature. In addition, polymorphism was observed in BP2 SAMs at all investigated temperatures. This study has demonstrated that solution temperature and incubation time are key factors controlling the two-dimensional SAM structure of BP2 molecules.
Synthesis, structures, and spectroscopic properties of copper(I) complexes bearing 7-acetamido-4-methyl-1,8-naphthyridin-2-carbaldehyde azine and 1,2-bis(diphenylphosphino)ethane ligands
Authors: Chi Shao-Ming , Wang Yu-Fei , Gan Xin , Wang De-Hui , Fu Wen-Fu 
Published: October 2009

Abstract
A new ligand napaa (napaa = 7-acetamido-4-methyl-1,8-naphthyridin-2-carbaldehyde azine) and its two dinuclear copper(I) complexes, Cu2(napaa)(dppe)2(ClO4)2 (1) and Cu2(napaa)(PPh3)4(BF4)2 (2) (dppe = 1,2-bis(diphenylphosphino)ethane) and PPh3 = triphenylphosphine) were synthesized and characterized, and the structure of 1 was determined by X-ray crystal analysis. Each copper atom in 1 has a distorted tetrahedral geometry in which the metal center is associated to napaa and dppe ligands displaying chelating coordination modes and the naphthyridine rings of napaa are almost coplanar. The two complexes exhibit similar electronic absorption spectra with λmax at about 366 nm, which can be tentatively assigned to metal-to-ligand charge-transfer (MLCT) transition. The assignment was further supported by density functional theory (DFT) calculations.
Two charge-transfer complex spectrophotometric methods for the determination of sulpiride in pharmaceutical formulations
Authors: Zayed Sayed 
Published: October 2009

Abstract
Two simple, rapid, accurate and sensitive spectrophotometric methods are described for the determination of sulpiride. They are based on charge transfer complexation between the drug as n-electron donor and p-chloranilic acid as π acceptor or iodine as σ-acceptor. These give highly coloured complexes with absorption maxima at 518 and 363, 294 nm, respectively. Beer’s law linear ranges were 13.7–341.4 and 1.7–20.5 µg mL−1 for the p-chloranilic acid and iodine methods. The methods were successfully applied to the determination of the drug in Dogmatil® Fort tablets and the results compared with the official method. The complex association constants and standard free energy changes were calculated using Benesi-Hildebrand plots.
QSPR modelling of the octanol/water partition coefficient of organometallic substances by optimal SMILES-based descriptors
Authors: Toropov Andrey , Toropova Alla , Benfenati Emilio 
Published: October 2009

Abstract
Usually, QSPR is not used to model organometallic compounds. We have modeled the octanol/water partition coefficient for organometallic compounds of Na, K, Ca, Cu, Fe, Zn, Ni, As, and Hg by optimal descriptors calculated with simplified molecular input line entry system (SMILES) notations. The best model is characterized by the following statistics: n=54, r2=0.9807, s=0.677, F=2636 (training set); n=26, r2=0.9693, s=0.969, F=759 (test set). Empirical criteria for the definition of the applicability domain for these models are discussed.
The study of cyclooctene oxidation with molecular oxygen catalyzed by VSi2
Authors: Makota Oksana , Trach Yuriy , Leboda Roman , Skubiszewska-Zięba Jadwiga 
Published: October 2009

Abstract
The catalytic effect of VSi2 on initial stages of the liquid-phase oxidation of cyclooctene by molecular oxygen was studied. The vanadium disilicide influences on the oxidation process in the presence of hydroperoxide. VSi2 takes part in a radical formation stage by catalysis of hydroperoxide decomposition reaction. The catalyst was investigated before and after reaction using FTIR spectroscopy. From the data obtained, the kinetic model of the catalytic oxidation process was proposed and the equation for the reaction rate was derived. The equation has described all observed dependences of reaction rate on the concentration of reactants and content of catalyst.
Carbon paste electrodes in the new millennium
Authors: Švancara Ivan , Walcarius Alain , Kalcher Kurt , Vytřas Karel 
Published: October 2009

Abstract
In this review (with 500 refs), both electrochemistry and electroanalysis with carbon paste-based electrodes, sensors, and detectors are of interest, when attention is focused on the research activities in the years of new millennium. Concerned are all important aspects of the field, from fundamental investigations with carbon paste as the electrode material, via laboratory examination of the first electrode prototypes, basic and advanced studies of various electrode processes and other phenomena, up to practical applications to the determination of inorganic ions, complexes, and molecules. The latter is presented in a series of extensive tables, offering a nearly complete survey of methods published within the period of 2001–2008. Finally, the latest trends and outstanding achievements are also outlined and future prospects given.
Equilibrium isotherm analysis of the sorption of congo red by palm kernel coat
Authors: Oladoja Nurudeen , Ololade Isaac , Idiaghe Justice , Egbon Emmanuel 
Published: October 2009

Abstract
The ability of Palm Kernel Coat (PKC), a waste agricultural product, in the abstraction of Congo Red (CR), an anionic dye, from aqueous solution was studied. The effects of sorbent dose and temperature were studied using batch sorption system. Isotherm experiments were conducted and the data obtained were fitted with different equilibrium isotherm equations namely, Langmuir, Freundlich, Dubinin-Radushkevich (D-R), Temkin, Harkins-Jura and Halsey isotherm equations. The Langmuir isotherm equation gave the best description of the sorption process and the maximum saturated monolayer sorption capacity of the PKC for CR was 79.37 mg g−1. Harkins-Jura isotherm equation gave the poorest description of the sorption process. The linear form of the Langmuir equation was used to analyze the data obtained when the sorbent dosage was optimized by method of continuous variation. The results obtained showed that the equilibrium monolayer sorption capacity, qm, of the PKC for CR decreased (79.37–17.07 mg g−1) with an increase in sorbent dosage. The relationship between the dimensionless parameter, KR, and initial concentration, Co, showed that the sorption of CR was favored at higher initial dye concentration and PKC dosages than the lower ones. The thermodynamic parameters, such as change in the free energy, the enthalpy and the entropy, were also evaluated. The thermodynamic analysis showed that the sorption is spontaneous and exothermic.
Various evaluations of a diffractive transmitted field of light through a one-dimensional metallic grating with subwavelength slits
Authors: Hu Bin , Gu Ben-Yuan , Dong Bi-Zhen , Zhang Yan , Liu Ming 
Published: October 2009

Abstract
We compare the Fresnel-Kirchhoff diffraction formula, the superposition of cylindrical waves, and the twodimensional (2D) Green’s function diffraction formula with a rigorous vector algorithm in calculating the near and intermediately transmitted field of light through a one-dimensional metallic grating with subwavelength slits. It is found that the results calculated by the 2D Green’s function diffraction formula coincide well with the precise result. The other evaluations deviate from the exact result by varying proportions. Our findings may provide a useful and precise way to analyze the transmitted field features of a metallic grating and subsequent possibility of achieving optimal designs for metallic optical elements with subwavelength scale.
Optics-less smart sensors and a possible mechanism of cutaneous vision in nature
Authors: Yaroslavsky Leonid , Goerzen Chad , Umansky Stanislav , Caulfield H. 
Published: October 2009

Abstract
Although optics-less cutaneous (“skin”) vision is not uncommon among living organisms, its mechanisms and capabilities have not been thoroughly investigated. This paper demonstrates, using methods from statistical parameter estimation theory and numerical simulations, that arrays of bare radiation detectors arranged on a planar or curved surface have the ability to perform imaging tasks without any optics at all. The working principle of this type of optics-less sensors and the model developed here for determining their performance may be used to shed light on possible mechanisms, capabilities and evolution of cutaneous vision in nature.
Background and muon counting rates in underground muon measurements with a plastic scintillator counter based on a wavelength shifting fibre and a multi-pixel avalanche photodiode readout
Authors: Volchenko Vladimir , Akhrameev Evgeniy , Bezrukov Leonid , Dzaparova Irina , Davitashvili Irakliy , Enqvist Timo , Fynbo Hans , Guliev Zhamal , Inzhechik Lev , Izmaylov Alexander , Joutsenvaara Jari , Khabibullin Marat , Khotjantsev Alexey , Kudenko Yuri , Kuusiniemi Pasi , Lubsandorzhiev Bayarto , Lubsandorzhiev Nima , Mineev Oleg , Olanterä Lauri , Petkov Valeriy , Poleshuk Roman , Räihä Tomi , Shaibonov Bator , Sarkamo Juho , Shaykhiev Alexey , Trzaska Wladyslaw , Volchenko Galina , Yanin Alexey , Yershov Nikolay 
Published: October 2009

Abstract
In this short note we present results of background measurements carried out with polystyrene based cast plastic 12.0×12.0×3.0 cm3 size scintillator counter with a wavelength shifting fibre and a multi-pixel Geiger mode avalanche photodiode readout in the Baksan underground laboratory at a depth of 200 metres of water equivalent. The total counting rate of the scintillator counter measured at this depth and at a threshold corresponding to ∼0.37 of a minimum ionizing particle is approximately 1.3 Hz.