bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of Two Methods of Interpretation of LangmuirProbe Data for an Inductively Coupled Oxygen Plasma
Authors: Chung T. H. , Shin Y. M. , Seo D. C. 
Published: June 2006

AbstractThe Langmuir probe technique has some drawback in applying to electronegative plasma since it is difficult to interpret the probe I – V data. The positive ion flux to the probe is modified due to the presence of negative ions. In this study, an inductively coupled oxygen RF plasma is employed to perform the Langmuir probe measurement of the electronegative discharge. Plasma parameters are obtained from Langmuir probe measurement using two different methods which are based on electron energy distribution function (EEDF) integrals, and the method based on the fluid model for the modified ion flux, respectively. The EEDF is measured by a double differentiation of the I – V characteristics according to the Druyvesteyn formula. The electron densities estimated based on the two methods are compared. The EEDF integral method gives little higher values than the modified ion flux method. It is observed that at low pressure the EEDF is close to a Maxwellian. Generally, as the pressure increases, the distributions switch to bi‐Maxwellian and to Druyvesteyn, and suggest some depletion of electrons with larger energies. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Experiments on the Angular Dependence of the Ion Energy Reflection Coefficient at Low Energies
Authors: Koch B. , Bohmeyer W. , Fussmann G. , Matyash K. , Schneider R. 
Published: June 2006

AbstractIn this paper we present a method of deriving the ion energy reflection coefficient R E from simultaneous measurements of the current‐ and energy flux density as functions of the bias voltage applied. R E is measured as a function of the angle in a low temperature magnetized plasma. The measurements were performed for different ion gyro radii covering the whole angular range between normal and grazing incidence. The values thus obtained for R E are in the range 0.2 to 0.4. They are below theoretical values calculated using the TRIM code. In case of small ion gyro radii r i, a strong angular dependence of R E is observed which does not occur for large r i. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Determination of Plasma Parameters from Thermal Probe Data
Authors: Matsuura H. , Jida T. 
Published: June 2006

AbstractThermal probe method uses heat flux data as the function of probe bias voltage. These data contain not only electron information but also ion one. In this paper, we applied a thermal probe to DC‐glow discharge plasma and test it to deduce electron and ion temperature. Obtained temperatures are in qualitative agreement with theoretical prediction, but the accuracy of heat flux measurement must be largely improved. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
PIC‐MCC Model of a Plasma in the Vicinity of a Cylindrical Langmuir Probe
Authors: Soberón F. 
Published: June 2006

AbstractA full kinetic model of an argon plasma in the vicinity of a cylindrical Langmuir probe is developed and presented. The model is one‐dimensional in the radial direction and three‐dimensional in velocity space. The model simulates the plasma transition from the bulk to the probe surface and particle collection by the probe. Monte Carlo particle‐neutral collisions are considered in the model to account for collisional effects on the probe particle collection. Particles are loaded at the plasma bulk boundary with Maxwellian velocity distribution functions. The model output includes space potential and particle density profiles as a function of radius. The model also reproduces typical Langmuir probe current‐voltage characteristics at different pressures, plasma parameters and probe dimensions. Modelled electron and ion currents at different pressures for similar plasma parameters are presented, analysed and compared. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Probe Diagnostics of Microwave Plasma at Frequency 2.45 GHz in CW and Pulse Regime
Authors: Straňák V. , Adámek P. , Blažek J. , Tichý M. , Špatenka P. 
Published: June 2006

AbstractThe paper is focused on diagnostics of newly developed surfatron‐based plasma source working at frequency 2.45 GHz. This plasma source of jet type can be operated in cw as well as in PC controlled pulse regime. We carried out diagnostic of the plasma exiting the nozzle by single and double Langmuir probe in cw as well as in pulsed regime of plasma source operation. The basic plasma parameters ‐ electron density and electron temperature ‐ are estimated from single probe measurements at low pressures. The electron temperature in wide range of pressures is evaluated from double probe measurements. Time evolution of electron temperature along a single period in pulsed mode of operation is measured and discussed. The exiting plasma stream is directly applied on a plastic material sample (PE) with the aim to increase its hydrophility. Degree of hydrophility is characterized by contact angle measurements. Relations between process plasma parameters and results of contact angle measurements are discussed. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Measurement of Plasma Parameters in Low Temperature High Density Hollow Cathode Plasma Jet Working in Magnetic Field
Authors: Virostko P. , Hubička Z. , Adámek P. , Čada M. , Olejníček J. , Tichý M. , Šícha M. 
Published: June 2006

AbstractLow temperature low pressure hollow cathode plasma jet system working in static magnetic field was investigated by means of time resolved Langmuir probe technique. The hollow cathode discharge was excited in a cylindrical nozzle fabricated from Ti by continuous DC, pulsed DC, continuous wave radio‐frequency (RF) and pulse‐modulated RF power. Pure Ar was used as working gas. Electron distribution, electron density, and effective electron temperature were measured and compared between the different plasma jet excitation modes. Time evolution of plasma parameters was studied and compared with time evolution of power absorbed in the discharge in pulsed DC and pulse‐modulated RF discharge excitation modes. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of Supersonic Ion Beams on the Triple Probe Measurement
Authors: Woo H.‐J. , Chung K.‐S. , Choi Y.‐S. , Lee M.‐J. , Zimmerman D. , McWilliams R. 
Published: June 2006

AbstractAlthough theory of the triple probe for Maxwellian plasma is well known, analysis with ion beams has not been established. Since plasma parameters, especially electron temperature, are distorted severely in the presence of supersonic ion beams, a new model for deducing electron temperature is introduced by solving the governing equations of the triple probe including the beam currents to three probe tips through simple assumptions. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis, Complexation and Spectrofluorometric Studies of a New NS3 Anthracene‐Containing Macrocyclic Ligand
Authors: Tamayo Abel , Escriche Lluis , Casabó Jaume , Covelo Berta , Lodeiro Carlos 
Published: June 2006

AbstractA new fluorescent device for detecting protons and metal ions, 11‐(9‐anthracenylmethyl)‐1,4,7‐trithia‐11‐azacyclotetradecane (L), has been synthesised. In addition, the photophysical properties of both the free and protonated species have been examined by absorption and fluorescence titrations of dichloromethane solutions of L with methanesulfonic acid. The coordinating properties of L toward PdII, ZnII, NiII and CoII have been studied both in solution and in the solid state. Different behaviours have been observed in the absorption and fluorescence titrations of L with the above‐mentioned transition‐metal ions. To evaluate whether these differences were due to the existence of equilibria between protonated and complexed species, such titrations have been repeated in the presence of an equivalent amount of acid. The structure of the [Pd(L)](BF4)2 complex has been solved by X‐ray crystallography. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Amino Acid Esters and Amides for Reductive Amination of Mucochloric Acid: Synthesis of Novel γ‐Lactams, Short Peptides and Antiseizure Agent Levetiracetam (Keppra®)
Authors: Das Sarma Koushik , Zhang Ji , Huang Yun , Davidson James G. 
Published: June 2006

AbstractA simple methodology utilizing mucochloric acid anddifferent α‐ and β‐amino acid esters, amides and shortpeptides for the synthesis of novel γ‐lactam and γ‐lactam‐based short peptides was developed. The synthesis of an antiseizure agent, Levetiracetam (Keppra®) was demonstrated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Bayesian hierarchical model for over‐dispersed count data: a case study for abundance of hake recruits
Authors: Mendes Jorge M. , Turkman K. F. , Jardim Ernesto 
Published: June 2006

AbstractIn this paper, we introduce a Bayesian Hierarchical model to estimate the abundance of hake recruits, as well as to study their spatial distributional patterns in the Portuguese territorial waters. Main objective of the paper is to improve on traditional empirical methods based on sampling averages and variances by using probabilistic models that capture spatial dependence structures. Copyright © 2006 John Wiley & Sons, Ltd.
Field‐enhanced scanning near‐field optical microscopy
Authors: Bouhelier Alexandre 
Published: June 2006

AbstractThis manuscript reviews the principles and recent advances of scanning near‐field optical microscopy based on tip‐induced field enhancement. These scanning microscopes utilize minute probes to locally enhance an electromagnetic field through a complex interplay between surface plasmon excitation and localization of electric charges by geometrical singularities. The necessary conditions leading to an electromagnetic enhancement will be reviewed, as well as the means to characterize it. A brief account of the theoretical framework will be given, together with applications of the technique ranging from chemical imaging to nanolithography. Microsc. Res. Tech., 2006. © 2006 Wiley‐Liss, Inc.
Autofluorescence properties of rat cerebellum cortex during postnatal development
Authors: Croce Anna C. , Pisu Maria B. , Roda Elisa , Avella Debora , Bernocchi Graziella , Bottiroli Giovanni 
Published: June 2006

AbstractBackground and ObjectivesThe multilayered structure of rat neocerebellum cortex (VI–VIII lobules of the vermis) during postnatal development undergoes rearrangements, which in turn are affected by treatment with the anti‐tumoral drug cisplatin. The dependence of autofluorescence emission properties on the tissue structural and molecular features has been investigated.Study design/Materials and MethodsAutofluorescence analysis was performed at defined time points of cerebellar histogenesis—11, 17, and 30 postnatal days‐ under normal conditions or after 5 µg/g body weight cisplatin treatment at 10 postnatal day. Autofluorescence signal was analyzed in vivo at the surface of intact lobules of cerebellum vermis by means of fiber optic spectrofluorometry, or on tissue sections by means of microspectrofluorometry and fluorescence imaging.ResultsIn vivo spectroscopy showed changes of autofluorescence signal both during normal histogenesis and after cisplatin treatment. External granular layer (EGL) and molecular layer (ML), that is, the more external layers were found to be interested by structural alterations, and showed the greatest changes in signal amplitude, accounting for the in vivo results. Fitting analysis indicated that changes in spectral shape reflected an increase in oxidative damages induced by cisplatin treatment.ConclusionsThe results confirm the relationship of the autofluorescence emission properties with histological and biochemical features of biological tissue. Lasers Surg. Med. 38:598–607, 2006. © 2006 Wiley‐Liss, Inc.
The Influence of Excess Coupling Agent on the Microdeformation Processes and Mechanical Properties of Poly(propylene)/Wood‐Flour Composites
Authors: Hristov Velichko , Krumova Marina , Michler Georg 
Published: June 2006

AbstractSummary: It is well known that coupling agents improve the adhesion between poly(propylene) and wood fillers leading to an increase of the composite mechanical properties. Above a certain concentration limit of the coupling agent, however, deterioration of the mechanical properties often occurs, and little attention has been directed so far towards finding out the reasons for that behavior. Transmission electron microscopy and high‐voltage electron microscopy were used in this work to study the morphology and microdeformation behavior of PP/wood‐flour composites modified with high amounts of maleated poly(propylene) as a coupling agent. It was found that the coupling agent containing a higher concentration of grafted maleic anhydride forms a separate phase in the poly(propylene) matrix, influencing the mechanical properties of the composites.HVEM micrograph of the deformation structure of wood‐filled poly(propylene) composite showing fibrils stretching between the coupling agent domains and the PP matrix.magnified imageHVEM micrograph of the deformation structure of wood‐filled poly(propylene) composite showing fibrils stretching between the coupling agent domains and the PP matrix.
Optical Fibers by Reactive Extrusion of Butyl Methacrylate
Authors: Berthet Romuald , Chalamet Yvan , Taha Mohamed , Zerroukhi Amar 
Published: June 2006

AbstractSummary: A process for the production of poly(butyl methacrylate) optical fibers by reactive extrusion is developed. The reactive system is adapted to the reduced reaction time in the extruder combining concepts based on the free volume theory and a kinetic model for the mass polymerization of butyl methacrylate. A kinetic model is proposed and the reaction evolution is simulated at different temperatures and initiator concentrations. This allows the choice of reaction conditions adequate for reactive extrusion technical limitations. Reactive extrusion experiments are carried out in a twin‐screw extruder and the effect of the different kinetic and process conditions on the reaction are analyzed in relation to the residence time distribution measured by an UV fluorescence method. Some optical properties of poly(butyl methacrylate) fibers are reported.Conversion versus the position along the screw length.magnified imageConversion versus the position along the screw length.
New Miscible Poly(ether imide)/Poly(phenyl sulfone) Blends
Authors: Ramiro Jorge , Eguiazábal José Ignacio , Nazábal Jon 
Published: June 2006

AbstractSummary: Blends of PEI and PPSU were prepared directly during the plasticization step of an injection molding process throughout the full composition range. The molded blends were transparent and showed a single glass transition and no dispersed phase by SEM. These characteristics did not allow the presence of a single miscibilized phase to be inferred unambiguously due to the very similar Tgs and refractive indices of the two components of the blends. Miscibility was inferred after close observation of the position, height and area of the enthalpy relaxation peak of the 50/50 blend. The modulus of elasticity and yield stress changed linearly with composition, leading to polymer materials with intermediate characteristics. The linearity was attributed to the lack of decrease in free volume induced by mixing and to the similar orientation of the components before and after mixing. The PPSU presence only slightly reduced the known tendency towards brittle fracture of PEI under notched impact conditions, but the presence of a single amorphous phase led to an expected ductile behavior of the blends close to that predicted by the single rule of mixtures.Break stress (•) and break strain (○) of PEI/PPSU blends as a function of composition.magnified imageBreak stress (•) and break strain (○) of PEI/PPSU blends as a function of composition.
New Results on the Correlation Molecular Architecture‐Melt Elasticity‐Blowing Process‐Film Properties for Conventional and Metallocene‐Catalyzed Polyethylenes
Authors: Leal Virginia , Lafuente Pilar , Alicante Raquel , Pérez Ruth , Santamaría Anton 
Published: June 2006

AbstractSummary: Melt elasticity of a series of conventional and metallocene‐catalyzed PEs is investigated. The samples show very noticeable differences in their molecular architecture, including a variable degree of LCB and MWD. Four parameters (De, RSI, recoverable shear and steady state compliance), determined through dynamic viscoelastic measurements, are correlated with molecular architecture and blown film properties. RSI parameter shows a particular capacity to discern the LCB effect from the MWD effect on PE melt elasticity. Enhancing melt elasticity improves bubble stability, but provokes more haze and poorer impact properties in the film.Dart impact values vs. relaxation spectrum index.magnified imageDart impact values vs. relaxation spectrum index.
Cover Picture: Macromol. Symp. 239/2006
Authors: Kaminsky W. , Funck A. , Wiemann K. 
Published: June 2006

Cover: Advancement in modern po lymer technologies such as photo‐electronics, pharmaceutical and biomedical fields, biodegradable systems and specific composites are increasingly interrelated. Urgent demands are apparent for new, eco‐efficient, advanced polymer systems, the development of which requires interdisciplinary knowledge. The common thinking of scientists specialized in certain segments of polymer science and technology was strongly initiated by the 8th International Symposium on Polymers for Advanced Technologies (PAT 2005) held in Budapest, September 2005.Convergent concepts can be seen in the developments of materials to be used as pharmaceuticals, biomaterials, polymer composites, fire retarded polymers, membranes, conductive systems and fuel cells. The presented unusual ways for various technologies of advanced polymer systems may initiate further research activities in the near future.Responding to the demand for better understanding of the advanced materials the conference covered the mechanistic and technological aspects of syntheses, composite and nanocomposite formation, and behaviour of polymeric materials in biomedical environment. As an example, the picture shows an SEM micrograph of carbon nanofibers in sPP (filler content: 0,6 %), taken from the contribution by W. Kaminsky.
Nanocomposites by In Situ Polymerization of Olefins with Metallocene Catalysts
Authors: Kaminsky W. , Funck A. , Wiemann K. 
Published: June 2006

AbstractNanoparticles such as silica balls (monopheres), calcium carbonate, carbon nanotubes (CNT) or fibers (CF) are uniformly coated with a film of polyolefins of variable thickness using metallocene/methyl‐aluminoxane (MAO) catalysts. The catalyst is adsorbed on the filler surface, leading to a polymer growth directly on its surface. Highly filled and stiff nano composites, basing on polyethene (PE) and syndiotactic or isotactic polypropene (sPP/iPP) with a content up to 85 wt% of silica or 7 wt% of multi‐walled carbon nanotubes (MWCNT) are obtained. MWCNT treated with MAO in the same way form a heterogenous cocatalyst for the preparation of iso‐ and syndiotactic PP/MWCNT composites, too. The uniformity of the dispersion depends primarily on the pretreatment of the filler.
Smart Reactivity in Gelatine/PNIPAM Mixtures: Control of the Cross‐Linking and Microheterogeneities
Authors: Boudet C. , Iliopoulos I. , Monti F. , Cloitre M. , Poncelet O. 
Published: June 2006

AbstractChemical cross‐linking of gelatine was achieved by using a thermo‐sensitive reactive poly(N‐isopropylacrylamide) as a cross‐linker. The reaction occurs only below the LCST. Controlled micro‐heterogeneities were created inside the gel without macroscopic volume transition. Acceleration of the drying process indicates faster water diffusion in the micro‐heterogeneous gel.
Swelling Behavior of N‐t‐butylacrylamide Copolymer and Terpolymers
Authors: Kaçmaz Ayşecik , Gürdağ Gülten 
Published: June 2006

AbstractCopolymers and terpolymers of N‐t‐butylacrylamide (TBA) with 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS) and N‐hydroxy methyl acrylamide (NHMAAM) were prepared by solution polymerization in a 1:1 (v/v) mixture of methanol and water at 50 °C keeping the TBA content in the feed constant at 60% based on mole ratio. The contents of AMPS or NHMAAM used for the preparation of TBA‐AMPS and TBA‐NHMAAM copolymers were 40 mole %. Molar percentages of AMPS and NHMAAM monomers in the feed for the preparation of TBA‐AMPS‐NHMAAM terpolymers were varied as 10:30, 20:20, and 30:10, respectively. The effects of temperature, AMPS and crosslinker contents, and the drying of swollen gels on the swelling behavior of ionic and non‐ionic TBA gels were investigated in distilled water between 10–50 °C and in buffer solutions having various pHs (1.9, 3.1, 5.6, 7.1, and 9.8) with constant ionic strength of 0.08 M at 20 °C using both the dry and the swollen forms of gels. The chemical structures and microscopic morphologies of the polymers were investigated by FTIR and SEM, respectively.
Molecular Dynamics of PGA Bioabsorbable Polymer During Isothermal Cold Crystallization
Authors: Kortaberria Galder , Jimeno Amaia , Arruti Puy , de la Caba Koro , Remiro Pedro , Eceiza Arantxa , Mondragon Iñaki 
Published: June 2006

AbstractAn investigation was carried out on the molecular dynamics of poly(glycolide) (PGA) in its completely amorphous state and during isothermal cold crystallization. Experimental results were generated over a wide range of frequency and temperature by broad‐band dielectric spectroscopy (DRS). The variation of the average relaxation time (defined as τ= ½πfmax where fmax is the frequency at maximum loss for the main α relaxation) has been studied during cold crystallization and the temperature dependence of this average relaxation time for completely amorphous and crystallized samples has been analyzed. This behaviour has been modelled by Havriliak‐Negami and Vogel‐Fulcher equations. The sensitiveness of the segmental dynamics to the degree of crystallinity has been analyzed, taking into account the relaxing segments and the amorphous layers between lamellae. Supporting evidence about the thermal behaviour of the polymers has been obtained with DSC. Complementarily, the evolution of the morphologies obtained during crystallization processes has been followed by optical microscopy.
Investigating the Time Dependent Behavior of Thermoplastic Polymers under Tensile Load
Authors: Vas László Mihály , Nagy Péter 
Published: June 2006

AbstractThe relationship between the results of the tensile and the stress relaxation tests of polypropylene specimens were analyzed and an attempt was made to find a way to estimate the former from the latter based on the measurements and the theory of linear viscoelasticity. The mechanical response of real polymers are basically of nonlinear character, therefore their behavior patterns do not meet the idealized (linear) ones. Experiments were performed on poly(propylene) (PP) as a test material and the stress relaxation behavior, as well as the linear elastic and linear viscoelastic approximation of the tensile load‐time curve were analyzed. To demonstrate the applicability of our idea and to perform the numerical calculations we have chosen a flexible function with three parameters to realize the nonlinear behavior.