bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Direct Electrochemical Route from Ilmenite to Hydrogen‐Storage Ferrotitanium Alloys
Authors: Ma Meng , Wang Dihua , Hu Xiaohong , Jin Xianbo , Chen George Z. 
Published: April 2006

AbstractAn unrecognised but predictable need for a hydrogen‐supported society is tens or even hundreds of million tonnes of hydrogen‐storage materials, and thus challenges existing technologies in terms of resource and economical realities. Ilmenite is an abundant mineral, and ferrotitanium alloys are among the earliest known hydrogen‐storage materials. At present, industrial production of ferrotitanium alloys goes through separate extraction of individual metals, followed by a multistep arc‐melting process. In particular, the extraction of titanium from ilmenite is highly energy intensive and tedious, accounting for titanium's high market price and restricted uses. This article reports the electrochemical synthesis of various ferrotitanium alloy powders directly from solid ilmenite in molten calcium chloride. More importantly, it demonstrates, for the first time, that such produced alloy powders can be used without further treatment for hydrogen storage and perform comparably with or better than similar products by means of other methods, but cost just a fraction.
Bis(2‐amino alcohol‐κN)dicarboxylatoplatinum(II) Complexes – Elegant Synthesis via Ring‐Opening of Bis(2‐amino alcoholato‐κ2N,O)platinum(II) Species with Dicarboxylic Acids
Authors: Meelich Kristof , Galanski Mathea Sophia , Arion Vladimir B. , Keppler Bernhard K. 
Published: April 2006

AbstractSynthesis and purification of bis(2‐amino alcohol‐κN)dicarboxylatoplatinum(II) complexes is problematic because of the use of light‐sensitive silver(I) salts and the competing ring‐closing side‐reactions, especially after release of the chloro‐ or iodo ligands of the dihalogeno starting platinum(II) species. A novel synthetic procedure, namely selective synthesis of doubly ring‐closed bis(2‐amino alcoholato‐κ2N,O)platinum(II) compounds as the purification step and subsequent coordination of dicarboxylates in the absence of silver(I) via a ring‐opening reaction, yielded a series of new complexes, which were characterized by elemental analysis, NMR spectroscopy, and X‐ray crystallography. Exemplarily, the ring‐opening of bis(2‐aminoethanolato‐κ2N,O)platinum(II) was performed in the NMR tube by means of oxalic acid and investigated by 1H and 195Pt NMR spectroscopy. The reaction was found to be highly efficient: within 3 h complete transformation to the dicarboxylatoplatinum(II) complex was observed. Contrary, when sodium oxalate was used, no reaction could be detected at all during a period of one day.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Management of environmental crop conditions to produce useful sunflower oil components
Authors: Roche Jane , Bouniols Andrée , Mouloungui Zéphirin , Barranco Thomas , Cerny Muriel 
Published: April 2006

AbstractThe objective of this study was to investigate the impact of water availability and temperature after flowering on oil, major fatty acid and sterol contents in seeds of standard and oleic sunflower genotypes, under managed and controlled field conditions. When water deficit was effective from the beginning to the end of anthesis, it modified the fatty acid composition of standard hybrids. When water was supplied, a major enhancement of oleic acid content was associated with a concomitant reduction of linoleic acid content and a decrease in saturated fatty acid contents. Higher temperatures increased the oleic acid content in seeds of standard hybrids. Oil content was enhanced under colder temperature and irrigation. The content of minor oil components, phytosterols, was also enhanced when seed development occurred under high temperature and severe water stress. As a whole, the data showed that combining water management, sowing date and choice of genotype may orientate the biosynthesis of seed components and thus generate seed composition variability suitable for industrial purposes.
Sodium Bis(trimethylsilyl)amide in the Oxidative Conversion of Aldehydes to Nitriles
Authors: Ru Hwu Jih , Fuh Wong Fung 
Published: April 2006

AbstractThe feasibility of the Me3Si species acting as a nucleofuge was investigated in compounds containing the NSiMe3 moiety. Treatment of various aromatic aldehydes with 2.2 equiv. of NaN(SiMe3)2 at 185 °C in a sealed tube produced the corresponding nitriles in high yields (81–98 %). In these reactions, NaN(SiMe3)2 acted as an oxidizing agent. Results from control experiments indicate that the Me3Si unit can depart efficiently from the NSiMe3 moiety of N‐silylimine intermediates. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Design considerations for low antenna correlation and mutual coupling reduction in multi antenna terminals
Authors: Thaysen Jesper , Jakobsen Kaj B. 
Published: April 2006

AbstractThe influence of mutual coupling on the envelope correlation between two identical planar inverted F‐antennas (PIFA) are investigated. The capacity of a multiple‐input multiple‐output (MIMO) antenna system strongly depends on the correlation between the antennas. By placing two antennas in a fixed area, it is found that the envelope correlation could be halved simply by proper mutual orientation. The set‐ups that maximise the distances between the open ends of the PIFAs yield the lowest mutual coupling as well as the lowest envelope correlations. It is found that the envelope correlation is 0.8 when the PIFAs are oriented in parallel. The envelope correlation can be decreased to 0.4 by rotating one of the PIFAs by 180 degrees. Copyright © 2006 AEIT
Acquisition performance for NDA symbol‐timing recovery with simple adaptive first‐order loops
Authors: Gappmair Wilfried , Flohberger Markus , Koudelka Otto 
Published: April 2006

AbstractPowerful feedforward estimators for symbol‐timing recovery are more or less mandatory for efficient acquisition in time‐division multiple access (TDMA) modems. However, in many cases, feedback solutions are much less complex from the computational point of view. The latter can be an attractive alternative for continuous transmission of data like DVB, where rapid acquisition is not so important as with TDMA. In order to describe analytically the acquisition performance of first‐order loops with Gardner detectors, it is shown that the related analog model can be successfully applied. In the sequel, this approach is used to demonstrate that the acquisition process may be accelerated significantly via simple adaptive loop filters. Copyright © 2006 AEIT
A small monetary system for the euro area based on German data
Authors: Brüggemann Ralf , Lütkepohl Helmut 
Published: April 2006

AbstractPrevious euro area money demand studies have used aggregated national time series data from the countries participating in the European Monetary Union (EMU). However, aggregation may be problematic because macroeconomic convergence processes have taken place in the countries of interest. Therefore, in this study, quarterly German data until 1998 are combined with data from the euro area from 1999 until 2002 and these series are used for fitting a small vector error correction model for the monetary sector of the EMU. A stable long‐run money demand relation is found for the full sample period. Moreover, impulse responses do not change much when the sample period is extended by the EMU period provided the break in the extended data series is captured by a simple dummy variable. Copyright © 2006 John Wiley & Sons, Ltd.
Long‐term cryopreservation of dental pulp stem cells (SBP‐DPSCs) and their differentiated osteoblasts: A cell source for tissue repair
Authors: Papaccio Gianpaolo , Graziano Antonio , d'Aquino Riccardo , Graziano Maria Francesca , Pirozzi Giuseppe , Menditti Dardo , De Rosa Alfredo , Carinci Francesco , Laino Gregorio 
Published: April 2006

AbstractIt is not known whether cells derived from stem cells retain their differentiation and morpho‐functional properties after long‐term cryopreservation. This information is of importance to evaluate their potential for long‐term storage with a view to subsequent use in therapy. Here, we describe the morpho‐functional properties of dental pulp stem cells (SBP‐DPSCs), and of their differentiated osteoblasts, recovered after long‐term cryopreservation. After storage for 2 years, we found that stem cells are still capable of differentiation, and that their differentiated cytotypes proliferate and produce woven bone tissue. In addition, cells still express all their respective surface antigens, confirming cellular integrity. In particular, SBP‐DPSCs differentiated into pre‐osteoblasts, showing diffuse positivity for ALP, BAP, RUNX‐2, and calcein. Recovered osteoblasts expressed bone‐specific markers and were easily recognizable ultrastructurally, with no alterations observed at this level. In addition, after in vivo transplantation, woven bone converted into a 3D lamellar bone type. Therefore, dental pulp stem cells and their osteoblast‐derived cells can be long‐term cryopreserved and may prove to be attractive for clinical applications. J. Cell. Physiol. 208: 319–325, 2006. © 2006 Wiley‐Liss, Inc.
Unimolecular Amphiphilic Nanocontainers Based on Dendronized Linear Polymers
Authors: Zhang Zhong‐Biao , Teng Yu‐Han , Freas William , Mohanty Dillip K. 
Published: April 2006

AbstractSummary: Linear polymeric core, polyethylenimine (PEI), is successfully dendronized divergently using different‐generation polyamidoamine (PAMAM)‐type dendrons. The formed dendronized polymers are further end‐capped using long alkyl acrylate, hexyl acrylate, to give macromolecular amphiphiles, which perform as unimolecular nanocontainers, capable of encapsulating water‐soluble dye in their interiors. The encapsulation properties are found to be generation‐dependent, in which, at higher generations of nanocontainers, the cavity becomes more localized, due to dense packing of the dendrons at their termini.Dendronization of a linear polymeric core followed by capping with hydrophobic arms.magnified imageDendronization of a linear polymeric core followed by capping with hydrophobic arms.
Salt‐Induced Depression of Lower Critical Solution Temperature in a Surface‐Grafted Neutral Thermoresponsive Polymer
Authors: Jhon Young K. , Bhat Rajendra R. , Jeong Changwoo , Rojas Orlando J. , Szleifer Igal , Genzer Jan 
Published: April 2006

AbstractSummary: Quartz crystal microbalance with dissipation monitoring (QCM‐D) is employed to determine the effect of salt on the volume phase transition of thermoresponsive polymer brushes. Changes in mass and viscoelasticity of poly(N‐isopropylacrylamide) (PNIPAM) layers grafted from a QCM‐D crystal are measured as a function of temperature, upon contact with aqueous solutions of varying salt concentrations. The phase‐transition temperature of PNIPAM brushes, TC,graft, quantified from the QCM‐D measurements is found to decrease as the concentration of salt is increased. This phenomenon is explained by the tendency of salt ions to affect the structure of water molecules (Hofmeister effect). However, in contrast to the linear decrease in phase‐transition temperature upon increasing salt concentration observed for free PNIPAM, the trend in TC,graft for PNIPAM brushes is distinctively non‐linear.Schematic representation of the effect of salt concentration on the phase transition behavior of thermoresponsive polymer brushes.magnified imageSchematic representation of the effect of salt concentration on the phase transition behavior of thermoresponsive polymer brushes.
Novel Water‐Soluble Poly(m‐benzamide)s: Precision Synthesis and Thermosensitivity in Aqueous Solution
Authors: Sugi Ryuji , Ohishi Tomoyuki , Yokoyama Akihiro , Yokozawa Tsutomu 
Published: April 2006

AbstractSummary: Chain‐growth polycondensations of 3‐aminobenzoic acid methyl esters 1a and 1b, bearing a tri‐ or tetra(ethylene glycol) methyl ether unit on the amino group, respectively, were carried out with lithium hexamethyldisilazide (LiHMDS) as a base and phenyl 4‐methylbenzoate (2) as an initiator in THF at 0 °C. The poly(m‐benzamide)s obtained in the presence of N,N,N′,N′‐tetramethylethylenediamine (TMEDA) possessed narrow molecular weight distributions ($\overline M _{\rm w} /\overline M _{\rm n}$ < 1.2) with molecular weights that were determined by the feed ratios of [1]0/[2]0. Poly1a and poly1b were each soluble in water and exhibited a lower critical solution temperature (LCST) in water. Furthermore, the phase separation in water depended on the length of the oligo(ethylene glycol) side chain and on the molecular weight and molecular weight distribution of poly1.Thermally sensitive water‐soluble poly(m‐benzamide)s.magnified imageThermally sensitive water‐soluble poly(m‐benzamide)s.
High Pressure Induced Coil‐Globule Transitions of Smart Polymers
Authors: Kirpach A. , Adolf D. 
Published: April 2006

AbstractSummary: In current work time‐resolved optical spectroscopy (TROS) has been used to study coil‐globule transitions monitored by the local segmental dynamics of anthracene labeled poly (N‐isopropymethacrylamide), PNIPMAM as a function of pressure (0.1 MPa–200 MPa) over a temperature range of 283 K to 333 K. The positions of temperature‐induced transition were observed to be independent on molecular weight of polymer at low pressures. The positions of pressure‐induced transition were observed to be dependent on molecular weight of polymer at temperatures below LCST at atmospheric pressure. Double globule‐coil‐globule transition was observed to occur with pressure increasing at temperatures nearly above LCST. All these results along with values of intrinsic viscosity evaluated from values of correlation times measured for globules formed at different pressure/temperature conditions suggest the different mechanisms of compactisation governed by pressure and temperature and, correspondently, the different types of final structures. At low pressures with temperature increasing the compact, well‐packed globules are forming via initial interactions between neighboring parts of polymer chain and further collapse. Relatively loosened particles are forming with pressurizing at low temperatures. Interaction between remote along the chain units takes part from the first stage of globule formation. And finally, rather solvated and irregularly twisted particles are forming at high pressure and high temperatures, i.e. at conditions, when both processes are involved.
Characterization of EO‐PO Block Copolymers by Liquid Chromatography Under Critical Conditions
Authors: Trathnigg Bernd , Gorbunov Alexei 
Published: April 2006

AbstractSummary:Block copolymers of ethylene oxide (EO) and propylene oxide (PO) are characterized by liquid chromatography under critical conditions (LCCC) for EO. At the critical adsorption point (CAP) for one structural unit, the non‐critical block can elute in size exclusion (SEC) or adsorption (LAC) mode. Depending on the molar mass and architecture of the polymers, different strategies are applied. For samples with a higher molar mass, the SEC separation is the method of choice, while lower molar masses also allow a LAC separation. Examples for both situations are given, which show, that these approaches yield different information. In the SEC mode, homopolymers and diblocks can be separated from the triblocks. In LAC mode, a baseline resolution of individual oligomers can be achieved, in which homopolymers, diblocks and triblocks with the same number of repeat units of the non‐critical block have the same elution volume.
The Swelling Behavior of Charged Hydrogels
Authors: Mann Bernward A. , Kremer Kurt , Holm Christian 
Published: April 2006

AbstractSummary:We describe recent advances obtained in understanding the microscopic interplay of a charged hydrogel with its confined mobile counterions. Results of extensive computer simulations are compared to simple scaling descriptions for various solvent conditions. We will briefly discuss our simulation package ESPResSo which was used to perform the simulations. We demonstrate why simple scaling theories suffice to adequately describe the swelling behavior of these systems despite their enormous complexity. We will conclude with a presentation of ongoing results for polyelectrolyte networks under poor solvent conditions.
Projectile Attack of Surface Scattered Munitions: Prompt Shock Finite Element Models and Live Trials
Authors: Almond Robert J. , Murray Stephen G. 
Published: April 2006

AbstractThis paper reports on continued research addressing remote neutralization of surface scattered explosive ordnance (principally anti‐tank mines). A clearance method has been proposed using a low cost vehicle mounted gun system, capable of rapid remote neutralization to a range of 100 m. Explicit non‐linear dynamic finite element models have been produced using a Lee‐Tarver representation of the explosive fill. This paper verifies these models against previous experimental data and closed form theory. Initial work on the use of explosive and hypergolic payloads is discussed.
Detonation Velocities and Pressures, and their Relationships with Electric Spark Sensitivities for Nitramines
Authors: Wang Gui‐Xiang , Xiao He‐Ming , Xu Xiao‐Juan , Ju Xue‐Hai 
Published: April 2006

AbstractThe DFT‐B3LYP method, with basis set 6–31G*, is employed to optimize molecular geometries and electronic structures of eighteen nitramines. The averaged molar volume (V) and theoretical density (ρ) are estimated using the Monte‐Carlo method based on 0.001 electrons/bohr3 density space. Subsequently, the detonation velocity (D) and pressure (P) of the explosives are estimated by using the Kamlet‐Jacobs equation on the basis of the theoretical density and heat of formation (ΔfH), which is calculated using the PM3 method. The reliability of this theoretical method and results are tested by comparing the theoretical values of ρ and D with the experimental or referenced values. The theoretical values of D and P are compared with the experimental values of electric spark sensitivity (EES). It is found that for the compounds with metylenenitramine units (CH2N(NO2)) in their molecules (such as ORDX, AcAn and HMX) or with the better symmetrical cyclic nitramines but excluding metylenenitramine units (such as DNDC and TNAD), there is a excellent linear relationship between the square of detonation velocity (D2) or the logarithm of detonation pressure (lg P) and electric spark sensitivity (EES). This suggests that in the molecular design of energetic materials, such a theoretical approach can be used to predict their EES values, which have been proven to be difficult to predict quantitatively or to synthesize.
Investigation of an N‐Butyl‐N‐(2‐Nitroxyethyl)Nitramine (BuNENA) Process: Identification of Process Intermediates, By‐Products and Reaction Pathways
Authors: Sitzmann Michael E. , Trivedi Nirupam J. , Skahan Patrick B. , Kenar James A. , Nock Lori A. , Stern Alfred G. 
Published: April 2006

AbstractA process for N‐butyl‐N‐(2‐nitroxyethyl)nitramine (BuNENA) was investigated: Step 1 involves N‐butyl‐ethanolamine addition to 98% HNO3 to form a salt mixture; Step 2 is addition of acetic anhydride/acetyl chloride catalyst to the salt mixture. A number of potential intermediates, by‐products, and decomposition products from this process were identified/synthesized for use as analytical standards. BuNENA process reaction pathways/mechanisms were elucidated, including the nature of the amine salt solution formed in Step 1. In addition, potential pathways that could account for by‐product formation were elaborated. A study of the consumption of acetyl nitrate in Step 2 was undertaken to prevent its build‐up.
Si‐oxide/Si and Si‐oxynitride/Si interfaces analysed by ultra‐low energy SIMS
Authors: Ćwil M. , Konarski P. , Bieniek T. , Beck R. B. 
Published: April 2006

AbstractDepth profile analyses of silicon oxides and oxynitrides are compared using SIMS (Secondary Ion Mass Spectrometry) technique with ultra low energy of primary Ar+ ion beam. SiO2 (5–80 nm thick) layers on p‐Si 〈100〉 were formed by thermal heating of silicon wafers in oxygen flow. SiOx Ny (2–4 nm thick) layers on p‐Si 〈100〉 were obtained by nitrogen implantation followed by plasma oxidation process. The nitrogen implantation was performed with NH3 and N2 plasma sources in 350 °C. The influence of r.f. power, used during implantation on the oxynitride layer properties, was studied.SIMS measurements were done using ultra‐low energy 880 eV Ar+ beam and quadrupole mass spectrometer. Quantitative atomic concentrations of nitrogen and oxygen were calculated basing on Si2N+, Si2O+ and Si2+ secondary ion currents. The obtained layers were also characterised by X‐ray Photoelectron Spectroscopy, ellipsometry and electrical tests. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Second harmonic generation in a molecular magnetic chain
Authors: Cavigli L. , Sessoli R. , Gurioli M. , Bogani L. 
Published: April 2006

AbstractA setup for the determination of all the components of the second harmonic generation tensor in molecular materials is presented. It allows overcoming depletion problems, which one can expect to be common in molecular systems. A preliminary characterization of the nonlinear properties of the single chain magnet CoPhOMe is carried out. We observe a high second harmonic signal, comparable to that of urea, and show that the bulk contributions are dominant over the surface ones. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation of iron oxide nanoparticles from FeCl3 solid powder using microemulsions
Authors: Nassar Nashaat , Husein Maen 
Published: April 2006

AbstractNanoparticles of iron oxide were prepared by subjecting iron chloride powder to (w/o) microemulsions consisting of sodium bis(2‐ethylhexyl) sulfosuccinate (AOT), isooctane and water. FeCl3 was first dissolved in the water pools of the microemulsion, and then reacted with NaOH added as an aqueous solution to form iron oxide. The amount of NaOH solution was limited so that single microemulsion phase is obtained. This technique serves as an in‐situ nanoparticle preparation technique aimed at minimizing particle aggregation associated with particle transportation to required sites. In this study, the effects of AOT concentration and water to AOT mole ratio on the nanoparticle size were investigated. UV/Vis spectrophotometry and transmission electron microscopy (TEM) were used to measure the particle size distribution. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation and characterization of polymer‐stabilized metal nanoparticles for sensor applications
Authors: Macanás J. , Farre M. , Muñoz M. , Alegret S. , Muraviev D. N. 
Published: April 2006

AbstractNanomaterial‐based sensing devices attract great attention of scientist and technologists due to the special properties of nano‐objects, such as for example, Metal Nanoclusters (MNC), which differ from those of the bulk materials. The further development of these devices requires novel approaches to stabilize MNC and therefore, to save their unique properties. The Solid‐Phase‐Incorporated‐Reagents (SPHINER) technique was used for in situ synthesis of Polymer‐Stabilized Metal Nanoclusters (PSMNC), which were used in the construction of new composite electrodes. The size of Pt‐PSMNC synthesized in polyvinyl chloride (PVC) and polysulfone stabilizing matrices was determined by Transmission Electron Microscopy (TEM) technique and appeared to be in majority of cases of 6–20 nm. The electrochemical characterization of PSMNC‐based amperometric sensors has demonstrated that inclusion of Pt‐MNC increases the electrical conductivity of the membrane and that the electrode performance strongly depends on both the type of polymeric matrix and the membrane preparation technique. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)