bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure and Dynamic Mechanical Properties of Melt Intercalated Polyamide 6—Montmorillonite Nanocomposites
Authors: Wilkinson Arthur N. , Man Zakaria , Stanford John L. , Matikainen Petri , Clemens Mark L. , Lees Graham C. , Liauw Christopher M. 
Published: August 2006

AbstractSummary: Polymer‐layered silicate nanocomposites (PLSN), based on polyamide 6 (PA6) and montmorillonite (MMT) modified with an octadecylammonium salt, were produced via melt compounding in a co‐rotating twin‐screw extruder. Wide angle X‐ray diffraction (WAXD) and TEM revealed a PLSN containing 3.3% by weight (wt.‐%) of MMT to exhibit a mixed exfoliated/intercalated morphology, consisting mainly of individual silicate lamellae together with some intercalated stacks, resulting in a mean value of 1.8 lamellae per particle. In contrast, a PLSN containing a higher level of 7.2 wt.‐% MMT exhibited a more ordered intercalated structure, consisting mainly of a distribution of lamellae stacks with a mean value of 3.8 lamellae per particle. The dispersion of MMT in the PLSN generated very large polymer–filler interfacial areas, resulting in significant increase in the volume of constrained PA6 chain segments. Consequently, significant changes in the ratio of α/γ crystallites and in the thermal behaviour of the matrix PA6 were observed during WAXD, DSC and dynamic‐mechanical thermal analysis (DMTA) studies of the PLSN. In particular, damping data from DMTA showed relaxations between Tg and Tm resulting from amorphous polymer chain segments constrained at the polymer–filler interface, indicating the formation of a continuous phase of constrained polymer. In contrast, a PA6 microcomposite formed using unmodified MMT generated much lower polymer–filler interfacial area, with most of the MMT residing within large, poorly wetted aggregates. Consequently, changes to the thermal behaviour of the matrix PA6 were much less significant than those induced in the PLSN.Shear storage modulus (G′) versus temperature data for the matrix PA6, the 5T and 10T PLSN and the 5P microcomposite.magnified imageShear storage modulus (G′) versus temperature data for the matrix PA6, the 5T and 10T PLSN and the 5P microcomposite.
Dynamic Monte Carlo Simulation of Atom‐Transfer Radical Polymerization
Authors: Al‐Harthi Mamdouh , Soares João B.P. , Simon Leonardo C. 
Published: August 2006

AbstractSummary: A dynamic Monte Carlo model was developed to simulate atom‐transfer radical polymerization (ATRP). The algorithm used to describe the polymerization includes activation, deactivation, propagation, chain transfer, and termination by combination and disproportionation reactions. Model probabilities are calculated from polymerization kinetic parameters and reactor conditions. The model was used to predict monomer conversion, average molecular weight, polydispersity and the complete molecular weight distribution at any polymerization time or monomer conversion. The model was validated with experimental results for styrene polymerization and compared with simulation results from a mathematical model that uses population balances and the method of moments. The simulations agree well with experimental and theoretical results reported in the literature. We also investigated the control volume size and number of iterations to reduce computation time while keeping an acceptable noise level in the Monte Carlo results.Comparison of the chain length distribution of polystyrene made with ATRP and conventional free radical (CFR) polymerization at 50% conversion. The initiator to monomer ratios are 1:100 (ATRP left peak), 1:500 (ATRP right peak), and 1:1000 (CFR).magnified imageComparison of the chain length distribution of polystyrene made with ATRP and conventional free radical (CFR) polymerization at 50% conversion. The initiator to monomer ratios are 1:100 (ATRP left peak), 1:500 (ATRP right peak), and 1:1000 (CFR).
Evaluation of age‐related labels by senior citizens
Authors: Weijters Bert , Geuens Maggie 
Published: July 2006

AbstractThe age‐related labels third age, elderly, 50+, senior, and retired were evaluated by a 40+ sample. Results of a qualitative and quantitative study showed that the labels third age and elderly evoked predominantly negative associations, and the evaluations of the latter three age‐related labels were generally positive. Cognitive age did not appear to add explanatory power, but group membership did (being retired or not, perceiving oneself as a senior or not). Moreover, a significant interaction effect between group membership and age emerged. When people did not belong or did not perceive themselves to belong to a given age group, the evaluation of the related label became more negative when the respondents approached the age to be eligible for group membership. After becoming or accepting to become part of the group, evaluations of the label increased again. On the basis of these results, an alternative‐stage model is proposed: status irrelevance, status rejection, status acceptance, and status championship. © 2006 Wiley Periodicals, Inc.
Peculiar and typical oligodendrocytes are involved in an uneven myelination pattern during the ontogeny of the lizard visual pathway
Authors: Santos Elena , Yanes Carmen M. , Monzón‐Mayor Maximina , del Mar Romero‐Alemán Maria 
Published: July 2006

AbstractWe studied the myelination of the visual pathway during the ontogeny of the lizard Gallotia galloti using immunohistochemical methods to stain the myelin basic protein (MBP) and proteolipid protein (PLP/DM20), and electron microscopy. The staining pattern for the PLP/DM20 and MBP overlapped during the lizard ontogeny and was first observed at E39 in cell bodies and fibers located in the temporal optic nerve, optic chiasm, middle optic tract, and in the stratum album centrale of the optic tectum (OT). The expression of these proteins extended to the nerve fiber layer (NFL) of the temporal retina and to the outer strata of the OT at E40. From hatching onwards, the labeling became stronger and extended to the entire visual pathway. Our ultrastructural data in postnatal and adult animals revealed the presence of both myelinated and unmyelinated retinal ganglion cell axons in all visual areas, with a tendency for the larger axons to show the thicker myelin sheaths. Moreover, two kinds of oligodendrocytes were described: peculiar oligodendrocytes displaying loose myelin sheaths were only observed in the NFL, whereas typical medium electron‐dense oligodendrocytes displaying compact myelin sheaths were observed in the rest of the visual areas. The weakest expression of the PLP/DM20 in the NFL of the retina appears to be linked to the loose appearance of its myelin sheaths. We conclude that typical and peculiar oligodendrocytes are involved in an uneven myelination process, which follows a temporo‐nasal and rostro‐caudal gradient in the retina and ON, and a ventro‐dorsal gradient in the OT. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006
Anomalous rheological properties of polyethylene molecular composites
Authors: Yamaguchi Masayuki 
Published: July 2006

AbstractThe effect of molecular weight on the rheological properties in the molten state has been studied for binary blends of high‐density polyethylene obtained by the Zieglar–Natta catalyst and low‐density polyethylene produced in an autoclave process. The blends composed of high‐density polyethylene with a high molecular weight and low‐density polyethylene show a higher drawdown force than the individual pure components, whereas the blends of high‐density polyethylene with a low molecular weight and low‐density polyethylene do not exhibit anomalous behavior. The pronounced drawdown force for the former blend system is attributed to the viscous enhancement in the linear viscoelastic region as well as the nonlinear strain‐hardening behavior in the elongational viscosity. POLYM. ENG. SCI. 46:1284–1291, 2006. © 2006 Society of Plastics Engineers
Three‐dimensional numerical simulation of injection molding filling of optical lens and multiscale geometry using finite element method
Authors: Kim Sang‐Woo , Turng Lih‐Sheng 
Published: July 2006

AbstractThis article presents the development, verification, and validation of three‐dimensional (3‐D) numerical simulation for injection molding filling of 3‐D parts and parts with microsurface features. For purpose of verification and comparison, two numerical models, the mixed model and the equal‐order model, were used to solve the Stokes equations with three different tetrahedral elements (Taylor‐Hood, MINI, and equal‐order). The control volume scheme with tetrahedral finite element mesh was used for tracking advancing melt fronts and the operator splitting method was selected to solve the energy equation. A new, simple memory management procedure was introduced to deal with the large sparse matrix system without using a huge amount of storage space. The numerical simulation was validated for mold filling of a 3‐D optical lens. The numerical simulation agreed very well with the experimental results and was useful in suggesting a better processing condition. As a new application area, a two‐step macro–micro filling approach was adopted for the filling analysis of a part with a micro‐surface feature to handle both macro and micro dimensions while avoiding an excessive number of elements. POLYM. ENG. SCI., 46:1263–1274, 2006. © 2006 Society of Plastics Engineers
Gold coating of polyethylene modified by argon plasma discharge
Authors: Švorčík V. , Kotál V. , Slepička P. , Bláhová O. , Šutta P. , Hnatowicz V. 
Published: July 2006

AbstractHigh density polyethylene (PE) was modified by argon plasma discharge and then coated with 50 nm thick gold layer. Surface morphology of as‐modified PE samples and samples coated with Au was studied using atomic force microscopy technique. The surface polarity was characterized by contact angles measured by standard goniometry. A nanoindenter was used to examine the sample's mechanical properties (hardness, elasticity modulus, scratch behavior). The Au layers were characterized using X‐ray diffraction. The plasma modification of PE leads to a strong decrease of the water contact angle, which further depends on the time elapsed after the plasma treatment. Because of plasma‐initiated ablation, a lamellar arrangement of PE polymeric chains becomes apparent on the plasma‐treated samples. The roughness of as‐modified PE decreases as a result of Au deposition. Plasma treatment increases PE microhardness but after subsequent Au deposition, both microhardness and elastic modulus decline. Scratch tests showed that while on Au‐coated pristine PE samples mainly elastic deformation was observed, on plasma‐treated and subsequently Au‐coated samples plastic deformation and mechanical deterioration played a significant role. According to the XRD analysis, Au film deposited on the modified PE should be the most stable. POLYM. ENG. SCI., 46:1326–1332, 2006. © 2006 Society of Plastics Engineers
Supramolecular control of spin‐crossover phenomena in lipophilic Fe(II)‐1,2,4‐triazole complexes
Authors: Kuroiwa Keita , Shibata Tomoko , Sasaki Sono , Ohba Masaaki , Takahara Atsushi , Kunitake Toyoki , Kimizuka Nobuo 
Published: July 2006

AbstractThe spin‐crossover properties of lipophilic, supramolecular Fe(II) complexes bridged by 4‐(3‐dodecyloxy)propyl‐1,2,4‐triazole [Fe(II)(1)3Cl2] were investigated in chloroform and cast films. A purple low‐spin (LS) complex in a powdery form was transformed into pale yellow high‐spin (HS) polymers by dissolution in chloroform. The formation of lipophilic molecular wires in chloroform was observed with transmission electron microscopy. The casting of chloroform solutions onto solid supports produced purple, transparent films (LS state). The cast films exhibited sluggish spin‐crossover (LS ⇋ HS) behavior without thermal hysteresis. On the other hand, the cocasting of equimolar dodecanol or tetradecanol with Fe(II)(1)3Cl2 produced composite films in which alcohol molecules were bound to the complex by ionic hydrogen bonding (ROH···Cl−) and van der Waals interactions. At room temperature, the cast films exhibited regular lamellar structures before and after alcohol doping; this was confirmed by wide‐angle X‐ray diffraction measurements. Interestingly, the Fe(II)(1)3Cl2/CnOH (n = 12 or 14) ternary films showed a reversible abrupt spin crossover accompanied by thermal hysteresis. The observed bistability was related to dynamic structural transformations between lamellar and hexagonal structures. This study provides a novel supramolecular approach to designing spin‐crossover polymer films with controlled thermal bistability. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5192–5202, 2006
Influence of the structure of nanoscopic building blocks on the assembly of micropatterned surfaces
Authors: Germack David S. , Harrisson Simon , Brown Gerald O. , Wooley Karen L. 
Published: July 2006

AbstractThe effect of solution‐state nanoscale structures on the assembly of micropatterns by solvent evaporation was explored with a novel amphiphilic diblock copolymer synthesized by reversible addition–fragmentation chain transfer polymerization. A copolymer of the structure poly(styrene‐alt‐maleic anhydride)75‐b‐isoprene84 was assembled into inverse micelles in toluene, and covalently stabilized in the core by reactive amidation of maleic anhydride residues with 2,2′‐(ethylenedioxy)bis(ethylamine) to create core‐crosslinked nanoparticles (CCNPs) or in the shell by the photoinitiated radical crosslinking reactions of isoprene units to create large crosslinked aggregates (LCAs) of heterogeneous sizes and shapes. Micropatterned films were prepared by the deposition of the diblock copolymer as a solution in acetone and the nanoscale structures (inverse micelle, crosslinked aggregate, and CCNP) as solutions in toluene onto trimethylysilyl chloride treated glass microscope slides under ambient conditions. An analysis by optical microscopy and tapping‐mode atomic force microscopy (AFM) indicated that the nanoscale surface topology could be controlled by the pre‐establishment of the block copolymer phase segregation into well‐defined core–shell nanoassemblies in solution. The most interesting films resulted from the evaporative deposition of inverse micelle and CCNP solutions, which afforded uniform, straplike micropatterns of similar dimensions on the microscale and low surface roughness on the nanoscale (roughness = 4 ± 1 and 6± 1 nm by AFM). © 2006 Wiley Periodicals, Inc. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5218–5228, 2006
Remarkable influence of heat treatment on the structural and superconducting properties of (Y1–xPrx)(BaSr)Cu3O6+z
Authors: Bouallal B. , Nafidi A. , El Abidi A. , Kaaouachi A. El 
Published: July 2006

AbstractWe report here on the preparation, X‐ray diffraction (XRD), Seebeck effect, AC magnetic susceptibility, resistivity measurements and effect of heat treatments in the high Tc superconductor (Y1–x Prx)(BaSr)Cu3O6+z . Each sample was subject to two types of heat treatment: oxygen annealing [O] and argon annealing followed by oxygen annealing [AO]. When x increase, the oxygen content (6+z) of the samples decrease slightly from 6.9 to 6.8 as determined by our iodometry measurements. The orthorhombicity ϵ = (b ‐a)/(b +a) decreases to zero at xt [O] = 0.6 and xt [AO] = 0.75. These indicate a structural phase transition from orthorhombic to tetragonal at xt. Whereas, Tc decrease to zero at xc [O] = 0.7 and xc [A,O] = 0.75. Therefore the [A,O] heat treatment increase xc. Note that ϵ decrease with Tc as foreseen. However, for a given x the [AO] heat treatment makes increase ϵ (Tc). Independently of heat treatment, a increase with x, whereas b decreased to its minimum at xt. For a given x < xt, the heat treatment [AO] makes decrease a and increase. A remarkable correlations were observed between Tc (x) and ϵ (x); and between the variation δTc (x) = Tc [AO]‐Tc [O] and δϵ (x). A combination of several factors such as decrease in the Cu (1)‐apical oxygen distance; cationic order of Prx on the (Sr,Ba) site along c axis, chain oxygen ordering on (O4,O5) sites; increase in p and in‐phase purity for the [AO] samples may qualitatively account for the observed data. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis of superconductor Bi‐2223 and its properties after partial oxygen substitution
Authors: Jakes V. , Sykorova D. , Smrckova O. , Vasek P. 
Published: July 2006

AbstractIn the first part of the work two routes of preparation of undoped superconductor Bi‐2223 are compared. The influence of addition of extra PbO is studied as well. The route that leads to higher content of the phase 2223 is then chosen as the appropriate way for preparation of fluorine doped samples of general stoichiometry Bi1.6Pb0.4Sr2Ca2.5Cu3.5Ox–z Fz (z = 0, 0.3, 0.6 and 0.9). These samples are characterized by measuring of their temperature dependence of electrical resistance and critical current density. Their phase composition is determined by XRD. While greater amount of fluorine widenes the superconducting transition and worsenes transport properties, the less doped sample shows increasement of critical current density. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Anomalies in magnetoelastic properties of NdFe10V2 alloy
Authors: Alinejad M. R. , Khandan Fadafan H. , Tajabor N. , Fruchart D. , Gignoux D. 
Published: July 2006

AbstractMagnetostriction and thermal expansion of NdFe10V2 alloy are reported. Experimental isotherms of the magnetostriction show a hill type maximum below 1 T which is more pronounced around 130 K, corresponding to that of spin‐reorientation transition in this alloy. The hills are accompanied by a large zero‐field magnetostrictivity. Hence, observed maxima are attributed to the minimum of magnetocrystalline anisotropy, which is expected at spin‐reorientation temperature. Isotherms of magnetostriction above 50 K saturate at fields of 4 T and above. Studying of the temperature dependence of saturation magnetostriction shows that the experimental results are in good agreement with the prediction of a theory composed by a combination of Callen's single particle model and mean‐field approximation of two particle magnetoelastic interactions. Thermal expansion measurements show that the thermal expansion coefficient is negligible at temperatures below 50 K, then increases with temperature linearly until 230 K, and finally remains constant, around 5×10–6 K–1, near room temperature. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and magnetic properties in the ruthenate Bi2.67Pr0.33Ru3O11
Authors: Zouari S. , Cheikh‐Rouhou A. , Ballou R. , Strobel P. 
Published: July 2006

AbstractAn unreported praseodymium substituted phase of the Bi‐Ru‐O system with formula Bi2.67Pr0.33Ru3O11was prepared. Its crystal structure and magnetic properties were investigated. Pr substituted occurs only on one of the two Bi sites. The magnetism of the compound is dominated by a Pr3+ contribution, that appears to interact antiferromagnetically. A non linear variation of the reciprocal magnetic susceptibility is observed that appears to account for crystal electric field interactions on the Pr3+ ions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of nitrogen insertion on the magnetic and structural properties of Sm2–xGdxFe17 alloys (0 ≤ x ≤ 2)
Authors: Ben Kraiem M. S. , Cheikhrouhou A. 
Published: July 2006

AbstractThe effect of nitrogen insertion on the structural and magnetic properties of Sm2–xGdxFe17Ny compounds (x = 0‐2) has been investigated. X‐ray diffraction patterns at room temperature show that all our synthesized samples are single phase and crystallize in the rhombohedral Th2Zn17‐type structure with very small amount of impurity. Nitrogen insertion leads to a monotonic increase in the unit cell volume, it leads also to an increase in the Curie temperature Tc from 425 K for SmGdFe17 to 760 K for SmGdFe17N3. Moreover, the nitrogen insertion increases the saturated magnetization Ms. Ms increases from 17.9 µB/mole for SmGdFe17 to 32.7 µB/mole for SmGdFe17N3. X‐ray diffraction measurements on magnetically aligned powder samples of Sm2–xGdxFe17Ny reveal a change in the easy magnetization direction from planar before nitrogen insertion to the c‐axis after nitrogen insertion. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Brillouin light scattering in ferromagnetic single layers: hysteresis loop and backward geometry
Authors: Djemia P. , Roussigné Y. , Chérif S.‐M. , Billet D. , Stashkevich A. , Moch P. 
Published: July 2006

AbstractWe present a Brillouin light scattering study of a thick ferromagnetic single layer Ni80Fe20 (44 nm) film, using two different geometrical setup: (i) the so‐called Damon‐Eschbach (DE) geometry where the in‐plane wave vector Q// of the studied spin wave is perpendicular to the external magnetic field H and (ii) the backward geometry (BW) where it is parallel to H (Q// and H lie in the film plane). An in‐plane uniaxial anisotropy that do not exceed 100 Oe is evidenced through the analysis of the variations of DE mode frequency and of the Stokes/anti‐Stokes dissymmetry versus H. The experimental magnetic Brillouin spectra showing the presence of dipolar and exchange standing spin waves are well reproduced for both geometries by our calculations of the scattered intensity using the following magnetic parameters: 4πM = 9400 G; g = 2.13; A = 0.93 10–6 erg.cm–1 for different values of the magnetic field H and of the in‐plane wave vector amplitude Q //. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Microstructure and magnetic behavior of PLD Sr2FeMoO6 thin films
Authors: Di Trolio A. , Larciprete R. , Marotta V. , Testa A. M. , Fiorani D. 
Published: July 2006

AbstractSr2FeMoO6 thin films, deposited by Pulsed Laser Deposition at fluence lower than 2 J/cm2, exhibit saturation magnetization and Curie temperature not far from the bulk theoretical values. On the contrary at fluence values higher than 3 J/cm2, a worsening of the ferromagnetic behavior together with an enhancement of the granularity turn up. X‐ray diffraction, magnetization and electrical transport reveal that the saturation magnetization, the Curie temperature and the transport properties of the films are influenced by the chemical composition and by the cation disorder. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of melt convection on microstructure evolution of Nd‐Fe‐B alloys using a forced crucible rotation technique
Authors: Biswas K. , Hermann R. , Filip O. , Acker J. , Gerbeth G. , Priede J. 
Published: July 2006

AbstractThe forced crucible rotation technique has been applied to the solidification of Nd‐Fe‐B alloys. Specially sealed samples were subjected to well‐defined forced rotation during induction heating and solidification. The resulting microstructure of the Nd‐Fe‐B alloys in consideration of melt convection has been investigated using scanning electron probe microscopy. The determination of the α‐Fe volume fraction by measuring the magnetic moment in a vibrating sample magnetometer (VSM) resulted in a distinct reduction of the α‐Fe volume fraction in samples with high crucible rotation frequencies. Furthermore, a new category of experiment has been started where a tailored magnetic field was applied in order to study the microstructure evolution due to an enhancement or suppression of the melt convection by additional alternating magnetic fields. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)