bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative investigation of novel PBI blend ionomer membranes from nonfluorinated and partially fluorinated poly arylene ethers
Authors: Kerres Jochen A. , Xing Danmin , Schönberger Frank 
Published: July 2006

AbstractIn this study, the properties of novel acid‐base blend membranes from polybenzimidazole PBI and self‐prepared sulfonated nonfluorinated and partially fluorinated arylene main chain polymers from the polymer classes of aromatic polyethers, polyetherketones, polyethersulfones, and polyphosphine oxides are comparatively discussed. The aims of this study were to (1) determine the influence of the chemical structure of the polymers on their thermal and chemical stabilities and to identify polymeric structures having stabilities as high as possible, and (2) determine the effect of the addition of PBI to sulfonated arylene ionomers in terms of improving of their chemical, thermal, and dimensional stabilities. The working hypothesis of the study was that partially fluorinated arylene main‐chain ionomers should have better chemical and thermal stabilities than the F‐free ionomers, due to the much higher stability of CF bonds, compared to that of CH bonds. Improved procedures have been used for the polycondensation reactions, by applying an excess of K2CO3 deprotonation compound; the use of a dehydration agent like toluene or benzene was not required. Further, reactions could be performed at lower temperatures than is usually required for such polycondensation reactions; most of the polycondensations were made in a temperature range between 80 and 130 °C. The following properties of the polymers and blend membranes have been determined: proton conductivity, water uptake, swelling, thermal stability including thermal stability of sulfonic acid groups and of the polymer backbone, and oxidative stability by H2O2 treatment. The result of these investigations was that polymers containing fluorinated building blocks and/or phosphine oxide building blocks had the best stabilities. Selected acid‐base blend membranes were made from PBI and these aromatic polymers showed proton conductivities of up to 0.1 S/cm, water uptake values of not more than 40%, and starting temperatures for SO3H group splitting‐off approaching 290 °C. Moreover, PBI‐sulfonated polymer blend membranes showed much less weight loss after H2O2 treatment than does the sulfonated polymers alone, indicating a radical attack‐stabilizing effect of PBI. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2311–2326, 2006
Sulfonated poly(aryl ether ether ketone ketone)s containing fluorinated moieties as proton exchange membrane materials
Authors: Liu Baijun , Robertson Gilles P. , Guiver Michael D. , Sun Yi‐Ming , Liu Yin‐Ling , Lai Juin‐Yih , Mikhailenko Serguei , Kaliaguine Serge 
Published: July 2006

AbstractA series of sulfonated poly(aryl ether ether ketone ketone)s statistical copolymers with high molecular weights were synthesized via an aromatic nucleophilic substitution polymerization. The sulfonation content (SC), defined as the number of sulfonic acid groups contained in an average repeat unit, could be controlled by the feed ratios of monomers. Flexible and strong membranes in sodium sulfonate form could be prepared by the solution casting method, and readily transformed to their proton forms by treating them in 2 N sulfuric acid. The polymers showed high Tgs, which increased with an increase in SC. Membranes prepared from the present sulfonated poly(ether ether ketone ketone) copolymers containing the hexafluoroisopropylidene moiety (SPEEKK‐6F) and copolymers containing the pendant 3,5‐ditrifluoromethylphenyl moiety (SPEEKK‐6FP) had lower water uptakes and lower swelling ratios in comparison with previously prepared copolymers containing 6F units. All of the polymers possessed proton conductivities higher than 1 × 10−2 S/cm at room temperature, and proton conductivity values of several polymers were comparable to that of Nafion at high relative humidity. Their thermal stability, oxidative stability, and mechanical properties were also evaluated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2299–2310, 2006
Effect of substituted IIIB transition metals on the energy gap of α‐Al2O3 by first‐principle calculations
Authors: Benam M. R. , Rahnamaye Aliabad H. A. , Hosseini S. M. 
Published: July 2006

AbstractSelf‐consistent band structure and density of states calculations were performed for the pure alumina (corundum phase) and the aluminates α‐Al2–x Tx O3 where T is a transition metal and stands for Sc, Y, La and Ac with x = 0.5. In this study we have employed the full potential linear augmented plane wave (FPLAPW) with generalized gradient approximations (GGA) based on the density functional theory (DFT). The results show that the size of the band gap in these alloys decreases considerably and these reductions are related to the ionic radius of the substituted transition metal. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Deposition of thallium sulfide layers on polyethylene and nanostructured silica by a sulfurisation‐reaction process
Authors: Bruzaite Ingrida , Snitka Valentinas , Janickis Vitalijus 
Published: July 2006

AbstractThallium sulfide layers on the surface of polyethylene are formed if they have been sulfured in a solution of higher polythionic acid, H2S33O6, and then treated with the alkaline solution of thallium(I) sulfate. Three phases TlS, Tl2S, Tl2S2 were identified by X‐ray diffraction analysis in thallium sulfide layers. Surface morphology of the films was characterized with a scanning electron microscope (SEM) and atomic force microscope (AFM). The films deposited on the PE substrate have a no‐homogeneous structure and consist of separated islands, the average roughness up to 10 µm. The deposition on the silica‐polystyrene beads matrix has a homogeneous structure and the average roughness is in the range of 100–150 nm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Properties of the CdTe/InSb interface studied by optical and surface analytical techniques
Authors: Feng Z. C. , Hung S. Y. , Wee A. T. S. 
Published: July 2006

AbstractIndium interdiffusion in MBE‐grown CdTe/InSb heterostructures was studied by optical and surface techniques of photoluminescence (PL), X‐ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). A correlation between the two types of investigations is established. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interface of atomic layer deposited Al2O3 on H‐terminated silicon
Authors: Gao K. Y. , Speck F. , Emtsev K. , Seyller Th. , Ley L. , Oswald M. , Hansch W. 
Published: July 2006

AbstractAl2O3 films 1 to 20 nm thick were deposited as alternative high‐κ gate dielectric on hydrogen‐terminated silicon by Atomic Layer Deposition (ALD) and characterized by Synchrotron X‐ray Photoelectron Spec‐troscopy (SXPS), Fourier Transform Infrared (FTIR) absorption spectroscopy and admittance measure‐ments. The SXPS results indicate that about 60% of the original Si–H surface bonds are preserved at the Al2O3/Si interface and this is confirmed by monitoring the Si–H stretching modes by FTIR spectroscopy in the Attenuated Total Reflection (ATR) mode both before and after ALD of Al2O3. The remaining 40% of Si–H bonds are replaced by Si–O bonds as verified by SXPS. In addition, a fraction of a monolayer of SiO2 forms on top of the Al2O3 dielectric during deposition. The presence of OH‐groups at a level of 3% of the total oxygen content was detected throughout the Al2O3 layer through a chemically shifted O 1s component in SXPS. Admittance measurements give a dielectric constant of 9.12, but a relatively high density of interface traps between 1011 and 1012 cm–2 eV–1. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High resolution transmission electron microscopy study on the nano‐scale twinning of θ‐NiMn precipitates in an Fe–Ni–Mn maraging alloy
Authors: Hossein Nedjad S. , Nili Ahmadabadi M. , Furuhara T. , Maki T. 
Published: July 2006

AbstractPrecipitation of nanometer‐sized fct θ‐NiMn intermetallic compound was found to cause age hardening in Fe–10Ni–7Mn (wt%) maraging alloy during isothermal aging at 753 K. High resolution transmission electron microscopy was used to study the substructure of the fct θ‐NiMn precipitates in the alloy after aging for 0.36 and 86.4 ks. Nano‐scale twins on (111) planes were found in the precipitates of intial and later stages of aging. Precipitation of bcc β‐NiMn at 753 K and subsequent martensitic transformation to fct θ‐NiMn during cooling to room temperature was suggested. It was also indicated that precipitation of fct θ‐NiMn at bcc iron matrix gives rise to high coherency strain energy. The (111) twinning is proposed to accommodate the strain energy of either martensitic transformation or coherency strain of precipitation reaction. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
In situ etch treatments of silicon carbide epitaxial layer for morphological quality improvement of the surfaces
Authors: Angelis S. De , Perrone D. , Scaltrito L. , Ferrero S. , Pirri C. F. , Mauceri M. , Leone S. , Pistone G. , Abbondanza G. , Crippa D. 
Published: July 2006

AbstractDifferent homo epitaxial 4H‐SiC commercial wafers were undergone hydrogen etching process that was developed in the reaction chamber of a Hot Wall Chemical Vapor Deposition (HWCVD) reactor. We have studied the effects of physical desorption to point out the morphology and the structural changes of epitaxial surfaces.An optical microscopy inspection was made to trace out a map of defect areas before and after etching treatments. We have analysed the morphological evolution of the surface in every etching process step by means of marked area on the defect map. We also achieved some other important information, concerning structural and morphological changing, by performing Atomic Force Microscopy and Micro Raman spectroscopy analysis on the same defect marked area.The etched epilayers showed a significant reduction of defects density and a good surface morphology. On investigated samples we fabricated Schottky diodes, their electrical behaviour compared to the devices fabricated on not etched epitaxial layer highlights the surface quality improvement and the increasing of SBD working yield. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preface: phys. stat. sol (a) 203/9
Authors: Dłużewski P. , Bristowe P. , Maurice J.‐L. , Komninou P. 
Published: July 2006

AbstractThis special issue contains a selection of papers that were presented at a symposium on Interfacial Processes and Properties of Advanced Materials (IPAM05) held at the E‐MRS Fall Meeting, Warsaw, Poland on 5–7 September 2005. The symposium was conceived and inspired by the success of its predecessor (IPAM04) held at the University of Caen, France in June 2004.The symposium attracted over sixty contributions and was organized around five areas: Interfaces and dislocations in compound semiconductors, Gate oxide interfaces, Interfaces and defects in electroceramics, Metal–metal interfaces and interfacial modeling, and Interfaces in nano‐structured and amorphous thin‐film systems. The focus was on the influence of buried interfaces on the functionality of various electronic and opto‐electronic devices such as lasers, ferroelectric memories, CMOS and magnetic disks. Therefore the materials addressed at the symposium included compound semiconductors (e.g. GaN, CdTe, ZnO), perovskites (e.g. SrTiO3), dielectrics (e.g. HfO2, SiO2, Al2O3), and metals (e.g. Fe/V superlattices). The aim of the symposium was to bring together leading interface experts, both experimental and theoretical, to explore the connection between interfacial properties (atomic and electronic structure, segregation, diffusion, kinetics) and materials performance in a device application. Papers were presented that described the use of a variety of sophisticated experimental techniques to explore the interfacial properties including HRTEM, X‐ray high‐resolution diffraction, Raman spectroscopy, STM, AFM, PL spectroscopy, SIMS and electrical and magnetic measurements. The theoretical work included applications of density functional theory, atomistic simulations, dislocation theory and finite element modeling. The program stimulated many exciting and productive discussions between experimentalists and theorists. The ultimate objective was to improve our knowledge of the role of interfaces on the properties of current and emerging device materials. It is hoped that these proceedings represent a step towards that goal and will encourage further conferences in this area in the future.The organisers gratefully acknowledge funding from the US Office of Naval Research Global (ONRG) Conference Support Program. They also would like to thank E‐MRS for their administrative support and the Institute of Physics, Polish Academy of Sciences and the Warsaw University of Technology for hosting the symposium. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Conceptual evaluation of methods for engineering situational ISD methods
Authors: Leppänen Mauri 
Published: July 2006

AbstractIn the past decades a large variety of techniques and methods have been introduced for software engineering (SE) and information system development (ISD). Despite this plurality, there is a need in organizations and projects to customize methods that match with their specific needs. Method engineering (ME) is the process by which a situational method is developed, customized and configured. ME work has appeared to be difficult and burdensome to carry out in practice. One reason for this is a lack of adequate methodical support. In this article, we profile and evaluate conceptually, using a contextual framework as a basis, seven comprehensive ME artifacts (i.e. techniques, procedures and methods) in terms of the support they contribute to ME work. The framework has been derived from relevant theories and experiences obtained from ME practice. The evaluation shows that the ME artifacts provide limited support for ME workflows and deploy perspectives that only partly cover the various aspects of ME contexts and SE/ISD contexts. The results of this study can help method engineers understand and structure the ME contexts at hand, recognize issues requiring particular concern, and make selections among ME artifacts. For researchers, the study reveals gaps and deficiencies in the support of ME artifacts, thus helping them direct their future research. Copyright © 2006 John Wiley & Sons, Ltd.
Adaptive modulation and combining for bandwidth and power efficient communication over fading channels
Authors: Belhaj Nesrine , Hamdi Noureddine , Alouini Mohamed‐Slim , Bouallegue Ammar 
Published: July 2006

AbstractTraditional fading mitigation techniques are designed relative to the worst‐case channel conditions, resulting in a poor utilization of the spectrum and the available power a good percentage of the time. In contrast, we introduce and investigate in this paper new adaptive modulation and diversity combining techniques that jointly select the most appropriate constellation size and the most suitable diversity branches in response to the channel variation and given a desired bit error rate (BER) requirement. Numerical results show that these newly proposed adaptive modulation and combining schemes can reduce considerably the average receiver channel estimation complexity as well as the power drain from the battery while offering high spectral efficiency and satisfying the desired outage probability and BER requirements. Copyright © 2006 John Wiley & Sons, Ltd.
Probability of error analysis of predetection generalized selection combining receivers with correlated unbalanced Nakagami branches
Authors: Al‐Hussien Abdel‐Hakim S. , Banat Mohammad M. 
Published: July 2006

AbstractIn this paper we determine the probability of error of a predetection generalized selection combining (GSC) receiver with correlated and unbalanced diversity branches in a Nakagami‐m multipath fading channel. We start by finding the joint probability density function (PDF) of the decision variables. This involves the derivation of the joint PDF of the L largest random variables (L maxima) of an input population of N > L correlated nonidentically distributed random variables, based on the statistics of the input population. The results obtained are then used in the derivation of the error probabilities of noncoherent FSK (NCFSK) and DPSK receivers. Copyright © 2006 John Wiley & Sons, Ltd.
Child protection in Sweden: Are routine assessments reliable?
Authors: Cocozza Madeleine , Gustafsson Per A. , Sydsjö Gunilla 
Published: July 2006

AbstractAim:To study the validity of the decision not to investigate mandatory reports of suspected child maltreatment.Methods:Written files of 220 reports indicating possible child maltreatment were analysed and re‐evaluated. As a measure of the justification for the decisions, a 5‐y follow‐up study was done.Results:We determined that 76% of the reports still indicated child maltreatment after the initial assessment was done. In the follow‐up study, 45% of the children had been investigated. The social worker used the family as the only source of information in 74% of the cases, in 6% someone outside the family was contacted, and in 11% no further information in addition to the report was collected. In 9%, data on information sources were missing.Conclusion:The findings are rather discouraging, as they challenge the belief that a report is a means of ensuring that maltreatment does not continue. The study shows that, depending upon the way in which the initial assessments are made, maltreated children may run a risk of not being identified, even though the maltreatment has been reported. This suggests that there may be a need for national guidelines concerning the reporting of maltreatment.
Hypothermia in the resuscitation of the neonate: A glance in my rear‐view mirror
Authors: Westin Björn 
Published: July 2006

AbstractRecent research indicates that the outcome of perinatal hypoxia‐ischaemia can be improved by hypothermia. This was actually first observed about 40 years ago, as discussed in this article. Clinical application of whole‐body hypothermia in the asphyxiated neonate showed a positive effect. Reference is made to previous review articles on the subject. A large experimental study indicated that the degree of protection against hypoxic‐ischaemic damage, as judged by the conditioned avoidance response, was dependent on the fall in body temperature. The earlier reported resistance against hypothermia in the asphyxiated neonate is discussed and analysed. Conclusion: Experimental and clinical evidence suggest that hypothermia may be of value in resuscitation of the neonate.
The impacts of different management strategies and environmental forcing in ecological communities
Authors: Enberg Katja , Fowler Mike S , Ranta Esa 
Published: July 2006

Understanding the effects of population management on the community a target species belongs to is of key importance for successful management. It is known that the removal or extinction of a single species in a community may lead to extinctions of other community members. In our study, we assess the impacts of population management on competitive communities, studying the response of both locally stable and unstable communities of varying size (between four and 10 species) to three different management strategies; harvesting of a target species, harvesting with non-targeted catch, and stocking of the target species. We also studied the consequences of selecting target species with different relative abundances, as well as the effects of varying environmental conditions.
We show here how the effects of management in competitive communities extend far beyond the target population. A crucial role is played by the underlying stability properties of the community under management. In general, locally unstable communities are more vulnerable to perturbation through management. Furthermore, the community response is shown to be sensitive to the relative density of the target species. Of considerable interest is the result that even a small (2.5%) increase in the population size of the target species through stocking may lead to extinction of other community members. These results emphasize the importance of considering and understanding multi-species interactions in population management.
The 5‐HT4 antagonist R216073 does not affect gastric motor and sensory function in patients with functional dyspepsia
Authors: VAN LELYVELD N. , TER LINDE J. , BARON A. , MUNDT M. , WAJS E. , SAMSOM M. 
Published: July 2006

SummaryBackground  Serotonin and the 5‐HT4 receptor play an important role in gastrointestinal motor and sensory functions. While 5‐HT4 agonists are known for their prokinetics properties, the effect of 5‐HT4 antagonists on upper gastrointestinal functions is largely unknown.Aim  To assess the effect of a 5‐HT4 receptor antagonist (R216073) on gastric relaxation and visceral sensitivity in patients with functional dyspepsia. Secondly, the influence of a functional polymorphism in the gene encoding the serotonin transport protein on drug response was determined.Methods  A double‐blind, randomized, placebo‐controlled, two‐period crossover study was performed in 20 functional dyspepsia patients. The effect of a single dose of 2000 mg R216073 on gastric relaxation and sensitivity was tested using three‐dimensional ultrasonography and a nutrient drinktest.Results  R216073 did not affect partial gastric volumes or upper abdominal sensations scored during three‐dimensional ultrasonography (P > 0.05). The maximum tolerated volume or upper abdominal sensations induced by the drinktest were not affected by R216073 (P > 0.05). The serotonin transport protein promoter polymorphism was not associated with any of the end‐points of the study.Conclusions  A single dose of R216073 had no effect on fundic relaxation, drinking capacity, or upper abdominal symptoms in patients with functional dyspepsia.
Nutritional status and prognosis in cirrhotic patients
Authors: GUNSAR F. , RAIMONDO M. L. , JONES S. , TERRENI N. , WONG C. , PATCH D. , SABIN C. , BURROUGHS A. K. 
Published: July 2006

SUMMARYBackground and Aim  The potential prognostic value for survival of nutritional status in cirrhotics after adjusting Child–Pugh classification and Model for End‐Stage Liver Disease has not been evaluated.Methods  We used Kaplan–Meier and Cox proportional hazards regression models to identify factors associated with mortality in a cohort of 222 cirrhotics [M/F:145/77 median age 52 (18–68) years] with prospectively collected nutritional parameters as well as modified subjective global nutritional assessment, Royal Free Hospital‐Subjective Global Assessment index. Follow‐up was censored at the time of transplantation. Other variables were ones in Child–Pugh and Model for End‐Stage Liver Disease scores, age, aetiology of cirrhosis and renal function,Results  Pretransplant mortality (Kaplan–Meier) was 21% by 2 years (135 patients were transplanted). Among the nutritional parameters, only Royal Free Hospital‐Subjective Global Assessment remained significantly associated with mortality in multivariable models (P = 0.0006). The final model included the following variables: urea (P = 0.0001), Royal Free Hospital‐Subjective Global Assessment (P = 0.003), age (P = 0.0001), Child–Pugh grade (P = 0.009) and prothrombin time (P = 0.003). The results were similar when the Child–Pugh grade was replaced by the Model for End‐Stage Liver Disease score in the model, and whether a competing risks model was used.Conclusions  Nutritional indices add significantly to both Child–Pugh grade and Model for End‐Stage Liver Disease scores when assessing the patient prognosis.