Nanostructured material based on Tin and Titanium Oxides: A potentiodynamic study

Films of a nanostructured material containing 90% SnO₂ and 10% TiO₂ (material ST10) are exhaustively studied by a potentiodynamic method in a lithium imide solution in dioxolane. The results are compared with x-ray diffraction data for freshly prepared and cycled samples.Translated from Elektrokhimiya, Vol. 41, No. 1, 2005, pp. 76–82.Original Russian Text Copyright © 2005 by Kulova, Roginskaya, Skundin.     

Composition of Inorganic Components of Buckwheat Husk and Straw

The composition of inorganic components and content of soluble substances in wastes from processing of seed (ordinary) buckwheat were studied in relation to the plant strain, type of a raw material (straw or husk), and processing conditions.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 2, 2005, pp. 329–333.Original Russian Text Copyright © 2005 by Zemnukhova, Shkorina, Fedorishcheva.     

Mass measurement uncertainty for plutonium aliquots assayed by controlled-potential coulometry

Minimizing plutonium measurement uncertainty is essential to nuclear material control and international safeguards. In 2005, the International Organization for Standardization (ISO) published ISO 12183 “Controlled-potential coulometric assay of plutonium,” 2nd edition. ISO 12183:2005 recommends a target of ±0.01% for the mass of original sample in the aliquot because it is a critical assay variable. Mass measurements in radiological containment were evaluated and uncertainties estimated. The uncertainty estimate for the mass measurement also includes uncertainty in correcting for buoyancy effects from air acting as a fluid and from decreased pressure of heated air from the specific heat of the plutonium isotopes.     

Development of Methods for the Production of Electrodes of Nonstoichiometric Compositions for Solid-Electrolyte Sensors with Predictable Sensitivity

The feasibility of application of sensor Me|Pb|PbCl₂-CaCl₂|Pb_{1 ± δ}|Me, where X = Se, Te, in an analysis of lead-containing gaseous environment is considered. The effect of the nature of the material, its nonstoichiometry, and the defect structure of measuring electrodes on the operation characteristics of these sensors is discussed. The mechanism of the formation of defects during the insertion of an electrochemically active component into the material of the measuring electrode is refined. The limiting stage of a process of a gas analysis is determined.__________Translated from Elektrokhimiya, Vol. 41, No. 6, 2005, pp. 728–734.Original Russian Text Copyright © 2005 by Leushina, Makhanova, Orzhaeva, Zlomanov.Published on the basis of a contribution delivered at the VII Meeting on Fundamental Problems in Solid-State Ionics (Chernogolovka-2004).     

Use of an Acrylic Dendron-containing Monomer in the Synthesis of a Macroporous Polymeric Material

A procedure was developed for preparing a monolithic macroporous material by photoinitiated co-polymerization of glycidyl methacrylate, ethylene glycol dimethacrylate, and an acrylic comonomer containing a dendron with protected terminal amino groups. The macropore formation is provided by a blowing agent.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 4, 2005, pp. 629-633.Original Russian Text Copyright © 2005 by Khimich, Tennikova.     

Xanthones from <Emphasis Type="Italic">Halenia corniculata</Emphasis>. 3. Preparation of Standard 1-Hydroxy-2,3,4,5-tetramethoxyxanthone

1-Hydroxy-2,3,4,5-tetramethoxyxanthone, which is used as a standard for quantitative determination of the total content of γ-pyrones, was isolated from the aerial part of Halenia corniculata L. Cornaz., an available raw material in Russia. A method for preparing standard 1-hydroxy-2,3,4,5-tetramethoxyxanthone was developed. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 420–421, September–October, 2005.     

On the Possibility of Using Protonic Solid Electrolyte CsHSO<Subscript>4</Subscript> in Hydrogen Fuel Cells

Electrochemical parameters of an H₂|air fuel cell with a membrane of solid electrolyte CsHSO₄ or composites (1 − x)CsHSO₄/xSiO₂ (x = 0.1–0.3) and different electrodes are measured at 175 °C. The maximal power (3.5 mW/cm² at a voltage of 0.6 V) is obtained for a cell with platinum-black electrodes and an intermediate layer of a mixture of platinum black and the electrolyte material. In the absence of a platinum catalyst, CsHSO₄ and composites CsHSO₄/SiO₂ are chemically stable in hydrogen at the operating temperature of the fuel cell.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 556–559.Original Russian Text Copyright © 2005 by Lavrova, Russkikh, Ponomareva, Uvarov.     

Formation of Iron-Carbon Nanoparticles behind Shock Waves

An attempt was made to obtain iron-carbon nanoparticles by two-step pyrolysis of Fe(CO)₅- and C₃O₂-containing mixtures behind incident and reflected shock waves in a shock tube. The formation of binary particles was monitored by recording the extinction of He-Ne laser radiation and laser-induced incandescence (LII). The LII method provides particle size estimates if the thermal and optical properties of the constituting material are known. Behind an incident shock wave, at temperatures of 700–1500 K, Fe(CO)₅ decomposes within a short period of time (∼50 µs). The resulting iron atoms combine into particles, which serve as condensation nuclei for carbon vapor resulting from C₃O₂ pyrolysis at 1500–3000 K behind the reflected shock wave. The binary particles thus produced are considerably larger than pure carbon or iron particles. As the mixture temperature behind the reflected shock wave is raised, the diameter of these binary particles decreases.__________Translated from Kinetika i Kataliz, Vol. 46, No. 3, 2005, pp. 333–343.Original Russian Text Copyright © 2005 by Gurentsov, Eremin, Roth, Starke.Based on a report at the VI Russian Conference on Mechanisms of Catalytic Reactions (Moscow, October 1–5, 2002).     

Synthetic diamond electrodes: Photoelectrochemical behavior of vacuum-annealed undoped polycrystalline diamond films

The photocurrent and photopotential for undoped polycrystalline diamond film electrodes prepared by chemical vapor deposition and annealed in vacuum at 1500–1640°C are measured. The metal-like samples (annealed at 1630°C) have a negligible photosensitivity. Judging from the positive sign of the photopotential and the cathodic direction of the photocurrent, the material under study formally behaves as a p-type semiconductor. The photoeffects are presumably caused by structure defects, in particular, the dislocations in diamond crystallites formed close to intercrystalline boundaries during the high-temperature annealing.Translated from Elektrokhimiya, Vol. 41, No. 3, 2005, pp. 343–349.Original Russian Text Copyright © 2005 by Pleskov, Krotova, Ralchenko, Khomich, Khmelnitskii.     

Piezoquartz microweighing study of interaction of water,alcohol, and hydrocarbon vapors with a macrocyclic copper(II) carboxylate complex

We have established that a bis(azamacrocyclic) complex of copper(II) with 1,3,5-benzenetricarboxylate undergoes reversible dehydration/rehydration processes. The rate of these processes and the high sensitivity of the material obtained to water vapor permit us to consider this compound as a promising coating for humidity sensors. Furthermore, such a coating differentiates between methanol and other monohydric alcohols.__________Translated from Teoreticheskaya i Éksperimentalnaya Khimiya, Vol. 41, No. 1, pp. 55–59, January–February, 2005.     

Image Intensification in Silver Halide Photographic Materials for Detection of High-Energy Radiation by Reprecipitation of Elemental Silver

A process for the intensification of silver images on AgHal photographic materials designed for detection of high-energy (X- and γ-ray) radiation was proposed, which is based on the “reprecipitation” of elemental silver and a decrease in its dispersion and comprises the treatment of silver with an aqueous solution containing potassium hexacyanoferrate(III) and potassium chloride or bromide at the first step and with a solution containing tin(II) chloride, potassium thiocyanate, sodium N,N′-ethylenediamine tetraacetate, and potassium hydroxide at the second step. By this process, the optical densities of image over a wide (0.5–2.0) range was increased by a factor of 3–5; as a result, the photographic sensitivity S _0.85 and S _2.00 was enhanced by almost an order of magnitude with the retained or slightly increased gradient g, fog density D ₀, and resolving power of the material.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 373–378.Original Russian Text Copyright © 2005 by Mikhailov, Kondakov, Krikunenko.     

Electrothermal vaporization in inductively coupled plasma atomic emission spectrometry for direct multielement analysis of food samples with slurry sampling

Slurry sampling followed by electrothermal vaporization (ETV) was used as sample introduction technique in inductively coupled plasma atomic emission spectrometry (ICP-AES) for the direct determination of trace elements in food samples. A polytetrafluoroethylene (PTFE) emulsion was used as a fluorinating reagent to promote vaporization and the transportation of analytes. The main factors affecting the analytical signals were investigated in detail. Under optimum operating conditions, the detection limits (DL) for this method varied from 1.8 (Cu) to 215 ng/mL (Zn), while the relative standard deviations (RSD) were in the range 2.6% (Cu)-7.2% (Zn). The proposed method was successfully applied to the direct determination of trace amounts of V, Cu, Cr, Fe, Zn, and La in rice without any chemical pretreatment. The precision was evaluated by analyzing a standard reference material (tea leaves, GBW 07605) and comparing the results from this method with results obtained by pneumatic nebulization (PN) ICP-AES after the wet-chemical decomposition of the same sample.From Zhurnal Analiticheskoi Khimii, Vol. 60, No. 3, 2005, pp. 286–290.Original English Text Copyright © 2005 by Chen.This article was submitted by the author in English.     

Synthesis of Ru(II) complex with 3-(4,5-dihydroimidazol-1-yl)propyltriethoxysilane containing viologen group

The nanostructured metallopolymers consisting of the partially quaternized 3-(4,5-dihydroimidazol-1-yl)propyl having the viologen group linked covalently through the alkyl spacer and its Ru(II) complex have been prepared by sol-gel method. Structural elucidation was done with Fourier transform infrared spectroscopy, ultraviolet spectroscopy and differential thermal analysis.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 183–186.Original Russian Text Copyright © 2005 by Gürbüz, Seçkin, Özdemir, Çetinkaya.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.     

Pseudo-Topochemical Synthesis of α-Fe in Aqueous Solution Using an Aluminum Matrix

Processes occurring in synthesis of α-Fe from a Fe(III) solution using an aluminum matrix were studied. The reaction kinetics strongly depends on the state of the matrix.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 2, 2005, pp. 177–183.Original Russian Text Copyright © 2005 by Dresvyannikov, Kolpakov.     

Multi‐center nature of heterogeneous Ziegler–Natta catalysts: TREF confirmation

A new approach to detailed Tref analysis of ethylene/α‐olefin copolymers prepared with multi‐center polymerization catalysts is developed. It is based on resolution of complex Tref curves into elemental components described with the Lorentz distribution function. This approach was applied to the study of a series of ethylene/1‐butene copolymers prepared with a supported Ti‐based catalyst. The analysis showed that the copolymers, which, on average, contain from 6.5 to 3.5 mol % of 1‐butene, consist of seven discrete components with different compositions, ranging from a completely amorphous material with a 1‐butene content of > 15–20 mol %, to two highly crystalline components with 1‐butene contents < 1 mol %. A comparison of these Tref results with the data on the molecular weight distribution of the copolymers (based on resolution of their GPC curves) shows that Tref and GPC data provide complimentary information on the properties of active centers in the catalysts in terms of the molecular weights of the material they produce and their ability to copolymerize α‐olefins with ethylene. Tref analysis of copolymers produced at different reaction times showed that the active centers responsible for the formation of various Tref components differ in the rates of their formation and in stability. The centers that produce copolymer molecules with a high 1‐butene content are formed rapidly but decay rapidly as well whereas the centers producing copolymer molecules with a low 1‐butene content are formed more slowly but are more stable. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4351–4362, 2005     

Porous Electrodes with Immobilized Enzymes: The Fractal-Percolation Properties of Supports Manufactured from Particles of Finely Divided Colloidal Graphite

The development of a porous active layer with an immobilized enzyme of a sufficiently large thickness is one of the problems that unavoidably emerge when constructing biofuel cells with high characteristics. Mounting up the thickness can be obstructed not only by the ohmic and diffusion limitations, which have been studied well enough. One more possibility of limitations (supports manufactured from finely divided colloidal graphite, FDCG), namely a “ fractal-percolation effect,” which has recently been discovered experimentally, is discussed in the paper. The essence of the effect consists of that the particles that are constituting a porous support may gather in random fractal clusters, which are connected with one another (the percolation part of the problem) with a probability that is other than unity. As a result, the electrons that are required for performing bioelectrocatalysis are capable of penetrating into a porous support only to a limited depth. Computer simulation of the fractal and percolation processes is performed in this work. As a result, quantitative relationship of the bulk concentration of FDCG in solution with the size of random fractal clusters, with the probability of their contact with one another, and with the degree of providedness of the material of the support by electrons is established. It may happen that all this information can become useful for the development of porous electrodes with an immobilized enzyme of high activity.__________Translated from Elektrokhimiya, Vol. 41, No. 8, 2005, pp. 943–953.Original Russian Text Copyright © 2005 by Chirkov, Rostokin.     

Wrinkles formed on a thin gold film deposited onto stretched elastic substrates

In this article the possibility of using various elastic polymer substrates for preparing wrinkled gold films was studied. The gold film was deposited on the substrate using an ion‐sputtering technique, while the substrate was stretched and fixed on a frame. The obtained gold film had wrinkles with a striped pattern. However, whether the pattern was well regulated or not depended on the substrate material. Polydimethylsiloxane (PDMS) was the preferable material when it did not contain fillers. Materials containing fillers are not suitable for this purpose. However, double layer substrates that consist of the PDMS without fillers (the upper layer) and the material containing fillers (the lower layer) could be used to obtain a relatively well‐ordered pattern. Copyright © 2005 John Wiley & Sons, Ltd.     

Ionic conduction of a high-temperature modification of Lu<Subscript>2</Subscript>Ti<Subscript>2</Subscript>O<Subscript>7</Subscript>

A nanoceramic product of the composition Lu₂Ti₂O₇ is synthesized by a coprecipitation method with a subsequent sublimation drying and an annealing at 650–1650°C. The conduction of Lu₂Ti₂O₇ synthesized at 1650°C is ionic (10^–3 S cm^–1 at 800°C). Thus, a new material with a high ionic conduction has been discovered. The ordering in Lu₂Ti₂O₇ is studied by methods of RFA, RSA, IK spectroscopy, electron microscopy, and impedance spectroscopy. The existence of a low-temperature phase transition fluorite-pyrochlore at 800°C and a high-temperature conversion order-disorder at 1650°C are established.Translated from Elektrokhimiya, Vol. 41, No. 3, 2005, pp. 298–303.Original Russian Text Copyright © 2005 by Shlyakhtina, Ukshe, Shcherbakova.     

A thick-film graphite-containing electrode modified with formazan for determining manganese in natural and drinking waters by stripping voltammetry

A mercury-free thick-film graphite-containing electrode modified with formazan is proposed for determining manganese(II) by cathodic stripping voltammetry. The detection limit for manganese(II) found with this electrode is 0.04 µg/L at a preconcentration time of 60 s. The analytical signal from manganese(II) is a linear function of its concentration in the range 0.1 to 30 µg/L. The results of determining manganese in natural and drinking waters are presented.Translated from Zhurnal Analiticheskoi Khimii, Vol. 60, No. 2, 2005, pp. 187–192.Original Russian Text Copyright © 2005 by Stozhko, Inzhevatova, Kolyadina, Lipunova.This revised version was published online in April 2005 with corrections to the author names and book review format.     

Rheological Properties of Blends of Ternary Copolyamide 6/66/610 with Chitosan

The viscosity of melts of a blend of a ternary copolyamide 6/66/610 and polysaccharide (chitosan) used as biodegradable additive was determined by capillary viscometry at 150–170°C.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 989–992.Original Russian Text Copyright © 2005 by Suvorova, Tyukova, Smirnova, Tymchishina.