bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparative study of temperature dependence of induction time and oscillatory frequency in polymer‐immobilized and free catalyst Belousov‐Zhabotinsky reactions
Authors: Pullela Srinivasa R. , Shen Jingyi , Marquez Manuel , Cheng Zhengdong 
Published: March 2009

AbstractEnvironment‐sensitive poly(N‐isopropylacrylamide) (PNIPAM) microgel particles with covalently bonded ruthenium(4‐vinyl‐4′‐methyl‐2,2′‐bipyridine) bis (2,2′‐bipyridine) [Ru(vmbipy)(bipy)2] display periodic size changes when placed in Belousov‐Zhabotinsky (BZ) reaction substrates. The temperature dependency of the induction time and oscillatory frequency of the BZ reaction in this polymer‐immobilized catalyst system were compared to the bulk BZ reaction with the catalyst in the solution phase. Prolonged induction times are observed for the immobilized catalyst, compared with free catalyst, while little difference is observed on the oscillation frequency. The Arrhenius frequency factor calculated using the induction time for the immobilized catalyst BZ reaction is about seven times smaller than that for the free catalyst Ru(bipy) case. On the other hand, the Arrhenius frequency factors calculated using the oscillatory frequency are almost the same, showing similar reaction kinetics during the BZ oscillations. The tunability of the induction time using a polymer matrix, as we observed here, while maintaining similar oscillatory behavior, should provide a new dimension to control the self‐assembling of BZ active particles. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 847–854, 2009
Effect of thermal history on the free volume properties of semi‐crystalline poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) membranes by positron annihilation lifetime spectroscopy
Authors: Cheng Mei‐Ling , Sun Yi‐Ming 
Published: March 2009

AbstractFree volume properties of a series of poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) membranes, which were produced by various nonisothermal crystallization processes (rapid‐, step‐, and slow‐cooling processes), were investigated using positron annihilation lifetime (PAL) spectroscopy over a temperature range of 25–90 °C. From the annihilation lifetime parameters, the temperature dependence of free volume size, amount, size distribution, and fractional free volume and thermal expansion properties of free volume were discussed. A model which assumed that amorphous phase was subdivided into mobile and rigid amorphous fractions (MAF and RAF) in the semicrystalline polymer was considered to interpret the temperature dependence of those free volume properties. Morphological observation of the semicrystalline polymer by small‐angle X‐ray scattering (SAXS) indicated that the rapid‐cooled (cold‐crystallized) membranes showed a much thinner thickness of the repeating lamellar/amorphous layers and most likely higher amount of RAF, which restrained the chain motion, than the step‐ and slow‐cooled (melt‐crystallized) membranes. The difference of free volume properties among various PHBV membranes was created according to the crystalline structure of the polymer from different thermal history. The polymer crystallized with slower cooling rate induced higher crystallinity and resulted in less free volume amount and lower fractional free volume. In addition, the thermal expansion coefficients of free volume size were affected by the crystallization rate of PHBV polymer. Larger distribution of the free volume size of melt‐crystallized membranes was observed as a result of the bimodal distribution of the lamellar periodicity and less amount of RAF than that of the cold‐crystallized membranes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 855–865, 2009
Effect of EVM/EVA‐g‐MAH ratio on the structure and properties of nylon 1010 blends
Authors: Yu Haiyang , Zhang Yong , Ren Wentan 
Published: March 2009

AbstractThe nylon 1010/ethylene‐vinyl acetate rubber (EVM)/maleated ethylene‐vinyl acetate copolymers (EVA‐g‐MAH) ternary blends were prepared. The effect of EVM/EVA‐g‐MAH ratio on the toughness of blends was examined. A super tough nylon 1010 blends were obtained by the incorporation of both EVM and EVA‐g‐MAH. Impact essential work of fracture (EWF) model was used to characterize the fracture behavior of the blends. The nylon/EVM/EVA‐g‐MAH (80/15/5) blend had the highest total fracture energy at a given ligament length (5 mm) and the highest dissipative energy density among all the studied blends. Scanning electron microscopy images showed the EVM and EVA‐g‐MAH existed as spherical particles in nylon 1010 matrix and their size decreased gradually with increasing EVA‐g‐MAH content. Large plastic deformation was observed on the impact fracture surface of the nylon/EVM/EVA‐g‐MAH (80/15/5) blend and related to its high impact strength. Then with increasing EVA‐g‐MAH proportion, the matrix shear yielding of nylon/EVM/EVA‐g‐MAH blends became less obvious. EVM and EVA‐g‐MAH greatly increased the apparent viscosity of nylon 1010, especially at low shear rates. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 877–887, 2009
A thermodynamic analysis of specific interactions in homoblends of poly(styrene‐co‐4‐vinylpyridine) and poly(styrene‐co‐methacrylic acid)
Authors: Elmiloudi Khaled , Djadoun Said 
Published: March 2009

AbstractMiscibility and strong specific interactions that occurred within homoblends of poly(styrene‐co‐4‐vinylpyridine) containing 15 mol % of 4‐vinylpyridine (PS4VP15) and poly(styrene‐co‐methacrylic acid) containing 15 mol % of methacrylic acid (PSMA15) have been examined by Fourier Transform infrared spectroscopy and DSC. The observed positive deviation of the glass transition temperature of the blends from the linear average line, was analyzed by the frequently used theoretical conventional approaches including the one very recently proposed by Brostow. A better fit was obtained when this latter is used. A reasonable agreement with experimental values was also obtained when the theoretical fitting parameter free method developed by Coleman, is applied to predict the composition dependence of the Tg of this system. A thermodynamic analysis of hydrogen bonding in this system was carried using the Painter‐Coleman association model and the variation of the Gibbs function of mixing and its different contributions and corresponding phase diagrams as a function of temperature and composition were estimated. This analysis predicted PSMA15 to be miscible with PS4VP15 in the whole composition range up to 150 °C. Above this temperature, a partial miscibility is predicted when the PS4VP15 is in excess. The DSC results are in agreement with these predictions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 923–931, 2009
Double yielding in PA6/TPV‐MAH blends: Effect of crosslinking degree of the dispersed phase
Authors: Tang Xue‐Gang , Yang Wei , Shan Gui‐Fang , Xie Bang‐Hu , Yang Ming‐Bo , Hou Meng 
Published: March 2009

AbstractThermoplastic vulcanizates (TPVs) based on PP and EPDM (the ratio is 5:5) with different crosslinking degrees were prepared using different contents of phenolic resins, and then blended with polyamide 6 (PA6). The results indicated that with an increase in crosslinking degree, the double yielding phenomenon in PA6/TPV blends became more distinct, the yield stress of the first yield point and the yield stress difference of the two yield points decreased; however, the yield strain of the first yield point did not change with the increasing crosslinking degree of the TPV, but the yield strain of the second yield point increased, resulting in a more broadened yield region. The SEM results showed that with an increase in the crosslinking degree of TPV, the diameter of TPV increased in the core layer, and the orientation degree of TPV in the skin and subskin layer deceased, accompanying with a decrease of the ratio of length to diameter (L/D) of the droplets. The morphology evolution of the PA6/TPV blend during the tensile test was also studied, and the results agreed well with the model we proposed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 912–922, 2009
Compressing the free energy range of substructure stabilities in iso‐1‐cytochrome c
Authors: Duncan Michael G. , Williams Michael D. , Bowler Bruce E. 
Published: March 2009

AbstractEvolutionary conservation of substructure architecture between yeast iso‐1‐cytochrome c and the well‐characterized horse cytochrome c is studied with limited proteolysis, the alkaline conformational transition and global unfolding with guanidine‐HCl. Mass spectral analysis of limited proteolysis cleavage products for iso‐1‐cytochrome c show that its least stable substructure is the same as horse cytochrome c. The limited proteolysis data yield a free energy of 3.8 ± 0.4 kcal mol−1 to unfold the least stable substructure compared with 5.05 ± 0.30 kcal mol−1 for global unfolding of iso‐1‐cytochrome c. Thus, substructure stabilities of iso‐1‐cytochrome c span only ∼1.2 kcal mol−1 compared with ∼8 kcal mol−1 for horse cytochrome c. Consistent with the less cooperative folding thus expected for the horse protein, the guanidine‐HCl m‐values are ∼3 kcal mol−1M−1 versus ∼4.5 kcal mol−1M−1 for horse versus yeast cytochrome c. The tight free energy spacing of the yeast cytochrome c substructures suggests that its folding has more branch points than for horse cytochrome c. Studies on a variant of iso‐1‐cytochrome c with an H26N mutation indicate that the least and most stable substructures unfold sequentially and the two least stable substructures unfold independently as for horse cytochrome c. Thus, important aspects of the substructure architecture of horse cytochrome c, albeit compressed energetically, are preserved evolutionally in yeast iso‐1‐cytochrome c.
About charge‐transport mechanisms in mesoporous silicon under adsorption of plant viruses
Authors: Vashpanov Yuriy , Son Jung‐Young , Kwack Kae‐Dal , Woo Sun‐Bo , Choi Kyu‐Hwan 
Published: March 2009

AbstractChanges in the electric parameters and the charge‐transport mechanism in a mesoporous silicon under adsorption of TORSV (tomato ringspot virus) and GFLV (grapevine fan leaf virus) NEPO‐viruses are analyzed. The mechanism influencing the electric characteristics of the mesoporous silicon under adsorption of the plant viruses is related with the changes in parameters of a potential‐barrier system due to redistribution of voltages at the silicon structure. The mechanism of charge transport in the mesoporous silicon is more likely connected to the changes in parameters of isotopic heterojunction barriers under small bias voltages, and it can be interpreted as Poole–Frenkel and tunnel conductivity for large bias. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Defect reduction in non‐polar (11$ \bar 2 $0) GaN grown on (1$ \bar 1 $02) sapphire
Authors: Johnston Carol F. , Kappers Menno J. , Moram Michelle A. , Hollander Jonathan L. , Humphreys Colin J. 
Published: March 2009

AbstractThis work assesses the relative effectiveness of different techniques to reduce defect density in heteroepitaxial, non‐polar, a ‐plane GaN films grown on r ‐plane sapphire by MOVPE. Plan view TEM was used to obtain the defect density of films grown by different methods. The as‐grown material was found to have a high dislocation and basal plane stacking fault (BSF) density (1.9 (± 0.2) × 1011 cm–2 and 1.1 (± 0.9) × 106 cm–1 respectively). The four defect reduction techniques tested were: 3D–2D growth, SiNx interlayers, ScN interlayers and epitaxial lateral overgrowth (ELOG). Both dislocation and BSF density were reduced by all methods compared to the as‐grown material. The lowest defect density was achieved in the (0001) wing of the ELOG sample and was <1 × 106 dislocations cm–2 and 2.0 (± 0.7) × 104 BSFs cm–1. On the wafer scale, ScN interlayers were most effective: A single 5 nm thick ScN interlayer reduced the BSF density to 5.9 (± 0.8) × 105 cm–1 and the dislocation density was reduced by two orders of magnitude to 1.8 (± 0.2) × 109 cm–2 compared to the as‐grown material. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Observation of novel defect structure in 2H‐AlN grown on 6H‐SiC(0001) substrates with 3‐bilayer‐height step‐and‐terrace structures
Authors: Okumura Hironori , Horita Masahiro , Kimoto Tsunenobu , Suda Jun 
Published: March 2009

Abstract250 nm thick AlN layers without a nucleation layer were grown directly on 6H‐SiC(0001) with 3‐bilayer‐height steps by rf‐plasma‐assisted molecular‐beam epitaxy. The structure and morphology of the AlN layers have been studied using atomic force microscopy, X‐ray diffraction and transmission electron microscopy. Two different types of unique defect structures were observed. Rows of pure‐edge‐type threading dislocations were observed along the pre‐existing step‐edges of the SiC substrate for AlN grown on as‐gas‐etched SiC substrates, while the planar defects threading through the AlN layer were observed at the step‐edges of the substrate for AlN on SiC with sacrificial oxidation. We concluded that these planar defects were the stacking mismatch boundaries due to the difference in stacking sequence of AlN layers on different SiC terraces. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Porous silicon/metal nanocomposite with tailored magnetic properties
Authors: Granitzer Petra , Rumpf Klemens , Poelt Peter , Krenn Heinz 
Published: March 2009

AbstractPorous silicon (PS) templates in the meso/macro porous regime with oriented pores clearly separated from each other and filled in a galvanic deposition process with various metals, especially ferromagnetic ones are magnetically investigated. The employment of different metals (e.g. Ni, Co, NiCo) together with the variation of the electrochemical deposition parameters modifies the structural characteristics of the PS/metal nanocomposite and thus leads to distinct magnetic properties of the hybrid system. Furthermore the use of different PS‐templates which means a change of the pore‐diameter and interpore spacing results also in various magnetic characteristics, especially influences on the magnetic interactions among the deposited metal nanostructures. Therefore the specimens show tailored magnetic properties like coercivity, squareness and magnetic anisotropy. The achieved nanocomposite merges electronic properties of a semiconductor with nanomagnetism and therefore opens the possibility of integrated spin‐based electronic devices. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Straining of thin Si films by partially oxidized meso‐porous Si substrates
Authors: Lysenko Vladimir , Ostapenko Dmytro , Bluet Jean‐Marie , Regregny Philippe , Mermoux Michel , Boucherif Abderraouf , Marty Olivier , Grenet Genevieve , Skryshevsky Valery , Guillot Gerard 
Published: March 2009

AbstractA simple and low‐cost technological approach for the straining of thin crystalline silicon (Si) films using porous silicon (PS) as stress generating nanomaterial is reported. Firstly, a technological approach allowing fabrication of thin Si films on a bulk meso‐PS substrate is described. Secondly, low temperature (<700 °C) oxidation of the PS/Si structures provokes a huge mechanical stress at nanoscale level inside the PS substrate. Consequently, the lateral PS straining induces biaxial deformation of the monocrystalline thin Si layer in the (100) plane parallel to the wafer surface. Raman scattering spectroscopy is used for the evaluation of strain values across the strained thin Si films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Semiconducting half‐Heusler and LiGaGe structure type compounds
Authors: Casper Frederick , Seshadri Ram , Felser Claudia 
Published: March 2009

AbstractCompounds with LiAlSi (half‐Heusler) and LiGaGe structure types have been investigated by means of band structure calculations. The LiAlSi structure type is known as the half‐Heusler structure type, whereas LiGaGe is a closely related hexagonal variant. A remarkable feature of some XYZ half‐Heusler compounds with 8 and 18 valence electrons is, that despite being composed of only metallic elements, they are semiconductors. More than 100 semiconducting compounds within these structure types are known. LiGaGe compounds have an additional degree of freedom, namely the degree of puckering of the layers. These compounds can become semiconducting at a certain degree of puckering. Half‐metallic behavior is rarely found in this structure type. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An extract from wild green oat improves rat behaviour
Authors: Schellekens Charlotte , Perrinjaquet‐Moccetti Tania , Wullschleger Carla , Heyne Andrea 
Published: March 2009

AbstractAn extract of wild green oat (Avena sativa L.), was tested in vivo in rats for its behavioural effects after chronic oral administration via extract‐admixed food. Thirty six male Sprague‐Dawley rats received (A) standard diet (controls), (B) 10 g/kg extract‐admixed food or (C) 100 g/kg extract‐admixed food. The following behavioural tests were performed: elevated plus maze, forced swimming, conditioned avoidance response and tetradic encounter. Body weight, food and fluid consumption were measured and apparent physical appearance was determined twice a week. Apart from a slightly decreased food and fluid intake in the high dose group there were no side effects observed during the treatment. The low dose led to an improvement of active stress response, an enhancement of shock avoidance learning and an increased synchrony in social behaviour. It may be concluded that the wild green oat extract is suitable to improve behavioural initiative in different situations. Copyright © 2009 John Wiley & Sons, Ltd.
Mesoscale GPS tomography applied to the 12 June 2002 convective initiation event of IHOP_2002
Authors: Champollion C. , Flamant C. , Bock O. , Masson F. , Turner D.D. , Weckwerth T. 
Published: March 2009

AbstractThe time‐varying three‐dimensional water vapour field derived from mesoscale Global Positioning System (GPS) tomography data is used to describe the water vapour variability in relation to the dynamics of the atmosphere during convective initiation (CI). The paper presents the theoretical framework of GPS tomography at the mesoscale, including aspects related to the assimilation of independent data (e.g. water vapour profiles issued from meteorological balloon soundings). GPS tomography‐derived water vapour density retrievals are validated against lidar, the Atmospheric Emitted Radiance Interferometer and radiosonde data, even if the short three‐day period of the study prevents conclusions about the real accuracy of the GPS tomography technique.GPS tomography products are used, in synergy with surface and sounding‐derived meteorological variable measurements, satellite imagery and reflectivity composites from the WSR‐88D network and S‐POL radar, to study environmental conditions leading to the 12 June 2002 CI event during the International H2O Project. On this day, CI was triggered simultaneously, shortly after 2100 UTC, in two locations along an old outflow boundary lying east‐west in the vicinity of the Oklahoma–Kansas border. The study focuses on CI to the east, which was triggered at the intersection of the outflow boundary with a distinct southwest–northeast‐oriented moisture convergence line. The latter formed as the result of a cross‐dryline circulation leading to the penetration of dry air meeting with the moister air mass associated with the southerly low‐level flow east of the dryline. These intersecting boundaries appeared to have provided the necessary triggering mechanism for getting moist surface air parcels up to the level of free convection. Tomography‐derived water vapour fields provided observational evidence of the vertical transport of water vapour above the lifting condensation level and the level of free convection to the south of and along the intersecting boundaries. Copyright © 2009 Royal Meteorological Society
Efficient moist physics schemes for data assimilation. I: Large‐scale clouds and condensation
Authors: Stiller O. , Ballard S. P. 
Published: March 2009

AbstractA cost‐effective, easily maintained linear cloud scheme is presented, which introduces the major effects of condensation and latent heat release and precipitation into the linear model of a four‐dimensional variational assimilation (4D‐Var) system. The condensation scheme is derived within the general framework of statistical cloud schemes and the approximations used make it applicable to a large variety of nonlinear schemes. Forecast trials indicated that the introduction of this scheme into the Met Office numerical weather prediction (NWP) model led to clear improvements of the forecast skill.Linearization test results are presented which show that the new scheme improves the match between linear and nonlinear models. An example of particularly large local improvements is found near the core of a low‐pressure system over the north Atlantic. Improvements are generally larger in the extratropics than in the tropics, where convection plays a dominant role in the nonlinear model (while it is not represented in the linear model). Experimental linearization tests (where the convection scheme of the nonlinear model has been switched off) show a particularly strong beneficial impact of the new scheme and enable the identification of some convection‐related compensating errors, which partially mask some of the new scheme's benefits when compared with a simpler linear scheme.The precipitation increments from the linear scheme are found to be broader and show less detail but capture many features of the corresponding increments obtained from the nonlinear model. A method of tuning and post‐processing the precipitation strength is presented and discussed. ©Crown Copyright 2009. Reproduced with the permission of HMSO. Published by John Wiley & Sons Ltd.
Estimation of Soil Organic Carbon Normalized Sorption Coefficient (Koc) Using Least Squares‐Support Vector Machine
Authors: Wang Bin , Chen Jingwen , Li Xuehua , Wang Ya‐nan , Chen Lin , Zhu Min , Yu Haiying , Kühne Ralph , Schüürmann Gerrit 
Published: March 2009

AbstractLeast squares‐support vector machine (LS‐SVM) was used to derive a quantitative structure‐activity relationship (QSAR) model for predicting the soil sorption coefficient normalized to organic carbon, Koc, from 24 fragment‐specific increments and four further molecular descriptors, employing a training set of 571 organic compounds and three external validation sets. The combinational parameters of LS‐SVM were optimized by adaptive random search technique (ARST). ARST could search the optimal combinational parameters of LS‐SVM from the solution space in a simple and quick way. The developed LS‐SVM model was compared with the model established by multiple linear regression (MLR) analysis using the same data sets. Generally, the LS‐SVM model performed slightly better than the MLR model with respect to goodness‐of‐fit, predictivity, and applicability domain (AD). The ADs of the LS‐SVM and MLR models were described on the basis of leverages and standardized residuals. Both the LS‐SVM and MLR models had wide ADs within a given reliability (standardized residual<3 SE units), but the LS‐SVM model was superior for compounds with high leverages.