bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tailoring Hydrogen Storage Materials Towards Application
Authors: Dornheim M. , Eigen N. , Barkhordarian G. , Klassen T. , Bormann R. 
Published: May 2006

AbstractA breakthrough in hydrogen storage technology was achieved by preparing nanocrystalline hydrides using high‐energy ball milling and the use of suitable catalysts/additives. These new materials show fast or in case of Mg‐based hydrides very fast absorption and desorption kinetics within minutes, thus qualifying lightweight Mg‐ or Al‐based hydrides for storage applications. This article summarizes our current understanding of the kinetics of Mg‐based light metal hydrides, describes an approach for a cost‐effective processing technology and highlights some promising new developments in lightweight metal hydride research.
Polyimide Asymmetric Membranes for Hydrogen Separation: Influence of Formation Conditions on Gas Transport Properties
Authors: Shishatskiy S. , Nistor C. , Popa M. , Nunes S. P. , Peinemann K. V. 
Published: May 2006

AbstractThe asymmetric flat sheet membrane was developed for separation of hydrogen from its mixtures with other gases. The composition of the casting solution and conditions of membrane preparation were optimized for the pilot scale membrane production. The resulting membrane have a high hydrogen flux (1 m3(STP)/m2h*bar) and selectivity of H2/CH4 at least 100, the value close to intrinsic selectivity of Matrimid 5218, material used for the asymmetric structure formation. The membrane is stable against mixtures of liquid hydrocarbons and can withstand heating up to 200 °C. The non‐woven fabric used as a support for the asymmetric membrane gives to the membrane excellent mechanical properties and allows to use the membrane in GKSS gas separation modules.
Developments in Membrane Research: from Material via Process Design to Industrial Application
Authors: Abetz V. , Brinkmann T. , Dijkstra M. , Ebert K. , Fritsch D. , Ohlrogge K. , Paul D. , Peinemann K.‐V. , Pereira‐Nunes S. , Scharnagl N. , Schossig M. 
Published: May 2006

AbstractThe aim of this review paper is to give an overview of the research activities of GKSS in the field of polymer based membranes. After summarizing the historic development of membrane science at GKSS, it describes different classes of polymeric materials for membranes, and the characterization of membranes. The design of membrane‐based separation processes followed by examples of applications will also be presented. In the last chapter we will try to give an outlook for the future activities in membrane research.
Recycling workflows and services through discovery and reuse
Authors: Wroe Chris , Goble Carole , Goderis Antoon , Lord Phillip , Miles Simon , Papay Juri , Alper Pinar , Moreau Luc 
Published: May 2006

AbstractScientific workflows are becoming a valuable tool for scientists to capture and automate e‐Science procedures. Their success brings the opportunity to publish, share, reuse and re‐purpose this explicitly captured knowledge. Within the $^{my}$Grid project, we have identified key resources that can be shared including complete workflows, fragments of workflows and constituent services. We have examined the alternative ways that these resources can be described by their authors (and subsequent users) and developed a unified descriptive model to support their later discovery. By basing this model on existing standards, we have been able to extend existing Web service and Semantic Web service infrastructure whilst still supporting the specific needs of the e‐Scientist. The $^{my}$Grid components enable a workflow life‐cycle that extends beyond execution to include the discovery of previous relevant designs, the reuse of those designs and their subsequent publication. Experience with example groups of scientists indicates that this cycle is valuable. The growing number of workflows and services mean more work is needed to support the user in effective ranking of search results and to support the re‐purposing process. Copyright © 2006 John Wiley & Sons, Ltd.
Single‐drop microextraction followed by in‐syringe derivatization and gas chromatography‐mass spectrometric detection for determination of organic acids in fruits and fruit juices
Authors: Saraji Mohammad , Mousavinia Fakhraldin 
Published: May 2006

AbstractA simple analytical procedure based on single‐drop microextraction combined with in‐syringe derivatization and GC–MS was developed for determination of some phenolic acids in fruits and fruit juices. Cinnamic acid,o‐coumaric acid, caffeic acid, andp‐hydroxybenzoic acid were used as model compounds. The analytes were extracted from a 3‐mL sample solution using 2.5 μL of hexyl acetate. The extracted phenolic acids were derivatized inside the syringe barrel using 0.7 μL ofN,O‐bis(trimethylsilyl)acetamide before injection into the GC–MS. The influence of derivatization conditions on the yield of in‐syringe silylation was studied. Experimental SDME parameters such as selection of organic solvent, solvent volume, extraction time, extraction temperature, pH, and ionic strength of the solution on the extraction performance were studied. The method provided fairly good precision for all compounds (2.4–11.9%). Detection limits were found to be between 0.6 and 164 ng/mL within an extraction time of 20 min in the GC–MS full scan mode.
Nonaqueous capillary electrophoresis coupled with laser‐induced native fluorescence detection for the analysis of berberine, palmatine, and jatrorrhizine in Chinese herbal medicines
Authors: Liu Qian , Liu Yingju , Li Yanqing , Yao Shouzhuo 
Published: May 2006

AbstractLIF detection is one of the most sensitive detection methods for CE. However, its application is limited because the analyte is usually required to be derivatized with a fluorescent label. As a result, LIF is seldom used to analyze active ingredients in plants. In this work, we introduce a rapid, simple, and sensitive method of nonaqueous CE (NACE) coupled with laser‐induced native fluorescence detection for the simultaneous analysis of berberine, palmatine, and jatrorrhizine. This method skillfully utilizes the native fluorescence of these alkaloids and requires no troublesome fluorescent derivatization. As these alkaloids can fluoresce to some degree, they were simply detected by a commercially available 488 nm Ar+ laser. The native fluorescence of the analytes was greatly enhanced by nonaqueous media. Compared with the reported UV detection method, much lower LOD was achieved (6.0 ng/mL for berberine, 7.5 ng/mL for palmatine, and 380 ng/mL for jatrorrhizine). This method was successfully applied to analyze berberine, palmatine, and jatrorrhizine in two Chinese herbal medicines, Rhizoma coptidis and Caulis mahoniae.
Free nilpotent minimum algebras
Authors: Busaniche Manuela 
Published: May 2006

AbstractIn the present paper we give a description of the free algebra over an arbitrary set of generators in the variety of nilpotent minimum algebras. Such description is given in terms of a weak Boolean product of directly indecomposable algebras over the Boolean space corresponding to the Boolean subalgebra of the free NM‐algebra. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthesis and swelling behaviour of poly (sodium acrylate)/sepiolite superabsorbent composites and nanocomposites
Authors: Santiago Francisca , Mucientes Antonio E , Osorio Mónica , Poblete Francisco J 
Published: May 2006

AbstractA series of novel composites and nanocomposites xerogels based on acrylic acid, sepiolite and N,N′‐methylenebisacrylamide were prepared using a solution polymerization technique at 70 °C. The quality of dispersion of the micronized sepiolite in the monomer is the crucial point for obtaining nanocomposites. A good dispersion explains the improvement of the absorbent properties of the nanocomposites with respect to the composites. This work investigates not only the influence of the mixing procedure on the swelling behaviour, but also the effect of the amount of clay on the absorbency of these hydrogels in deionized water and saline solution (0.2 wt% NaCl(aq)). A crosslinker concentration of 5 wt% sepiolite nanocomposite superabsorbent was shown to give the best results (1419 g g−1). Moreover, experimental results indicate that the absorbency in saline solution is smaller than that in deionized water. Rates of swelling for these absorbents were found to fit the Voigt expression. Finally, the model approximates Case II sorption in the early stages of the swelling process and Case I in the later stages. Copyright © 2006 Society of Chemical Industry
Synthesis and optical and thermal properties of poly[methyl(2,9‐diphenyl‐ 7,8‐benzophenanthryl)silylene‐co‐1,4‐bis(methylphenylsilyl)phenylene]
Authors: Li MeiJiang , Qiu HuaYu , Jiang JianXiong , Ni Yong , Lai GuoQiao , Feng Shengyu 
Published: May 2006

AbstractPoly[methyl(2,9‐diphenyl‐7,8‐benzophenanthryl)silylene‐co‐1,4‐bis(methylphenylsilyl)phenylene] (PMBS‐co‐BSP) was synthesized by the condensation reaction of dichloromethyl(2,9‐diphenyl‐7,8‐benzophenanthryl)silane and 1,4‐bis(chloromethylphenylsilyl)benzene with sodium in toluene. Optical and thermal behavior of the polymer was investigated. Because of the introduction of substituted benzophenanthryl groups into the Si atoms of the polymer, the UV absorption wavelength of the PMBS‐co‐BSP red‐shifted significantly in the UV region, and a strong photoluminescence band was observed in the visible region other than the near‐UV photoluminescence typical of normal polysilane. The photochemical behavior was examined both in solution and in thin film by fluorescence and UV spectroscopy. Irradiation of the PMBS‐co‐BSP with a low‐pressure mercury lamp in solution resulted in homolytic scission of silicone–silicone bonds; the fluorescence emission intensities decreased gradually with increasing UV irradiation time and the maximum emission wavelength blue‐shifted significantly. Irradiation of thin solid films of the PMBS‐co‐BSP in air led to the formation of photoproducts containing SiOH and SiOSi groups. The PMBS‐co‐BSP began to weigh less at about 300 °C and the weight loss of the polymer at 700 °C was calculated to be 75% of the initial weight in N2. Copyright © 2006 Society of Chemical Industry
High quantum efficiency InGaN/GaN structures emitting at 540 nm
Authors: Graham D. M. , Dawson P. , Godfrey M. J. , Kappers M. J. , Costa P. M. F. J. , Vickers M. E. , Datta R. , Humphreys C. J. , Thrush E. J. 
Published: May 2006

AbstractWe present a study of the optical properties of a series of InGaN/GaN multiple quantum well structures, with room temperature peak emission wavelengths of 540 nm. By adopting a two‐temperature growth method and designing structures to have short radiative lifetimes, we have obtained room temperature internal photoluminescence quantum efficiencies of 8%. Transmission electron microscopy images have revealed the presence of edge‐type threading misfit dislocations in the multiple quantum well stack, which may be preventing the efficiency from reaching the very high values obtained in blue emitting InGaN/GaN multiple quantum well structures. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atomic structure of dislocations in nitride semiconductors
Authors: Petit S. , Béré A. , Chen J. , Belabbas I. , Ruterana P. , Nouet G. 
Published: May 2006

AbstractThe 1/3<11‐20> edge dislocation is present in the GaN layers. Its atomic core is described by three configurations, 5/7, 8 and 4 atom rings. Besides the isolated dislocations, this dislocation is involved in the intrinsic structure of coincidence <0001> tilt grain boundaries. In this work, the atomic structures based on the three cores and the associated energies of this dislocation, in Σ = 7 grain boundary, are calculated with the ab initio code AIMPRO. The values of energies and bond lengths are compared to the values previously obtained by using an empirical potential and a tight‐binding method. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Clustering in GaAsSbN alloys as a possible origin of their atypical optical behavior: a Sb K‐edge X‐ray absorption study
Authors: Ciatto Gianluca , Harmand Jean‐Christophe , Largeau Ludovic , Glas Frank 
Published: May 2006

AbstractGaAsSbN and InGaAsSbN alloys have been recently designed for obtaining laser emission on GaAs substrate near the second minimum for attenuation in silica optical fibers. Thermal annealing of the alloys, which is necessary in order to optimize the emission, brings about a larger blue‐shift of the band gap than in Sb‐free alloys; moreover the optical bowing is larger compared to other dilute nitrides. In this paper we investigate the possibility for structural short‐range ordering (SRO) to be at the origin of these emission properties, using X‐Ray Absorption Spectroscopy at the Sb K‐edge; our preliminary results seem to indicate that the occurrence of Sb clustering depends strongly on the growth conditions, and in particular on the substrate temperature. We found that the blue‐shift of the band gap upon annealing is not necessarily accompanied by Sb clustering in the V lattice, and the correlation between SRO and optical properties is still unclear; rearrangement of N atoms in the V‐lattice might be the key to account for the optical observation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AlN/GaN superlattices: strain relaxation
Authors: Bellet‐Amalric E. , Amstatt B. , Daudin B. 
Published: May 2006

AbstractA serie of AlN/GaN superlattices with thin period (fewer than 6 monolayers) was grown by plasma‐assisted molecular beam epitaxy. Their strain relaxation is address by in‐situ reflection high energy electron diffraction (RHEED). Three distinct phenomena can be distinguished; two of them are related to a dislocation introduction mechanism (at the first monolayers or all along the sample) and the third correspond to a periodic elastic strain relaxation. Their relative importance depends on growth conditions and should be taken into account while designing a complete superlattice structure. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
p‐type conduction in a C‐doped (1‐101)GaN grown on a 7‐degree‐off oriented (001)Si substrate by selective MOVPE
Authors: Hikosaka T. , Koide N. , Honda Y. , Yamaguchi M. , Sawaki N. 
Published: May 2006

AbstractUsing a selective metal organic vapour phase epitaxy method, (1‐101)GaN was grown on a (001)Si substrate. Intentional carbon doping was attempted using CCl4 as the souce gas and the electrical properties were studied as a function of the doping level. All samples showed the p‐type conduction. The hole concentration was increased by the doping, determined by the ratio of the carbon source and NH3 flow rates. The results indecated that the p‐type conduction is due to the incorporation of carbon in the (1‐101)GaN. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and doping of AlGaN and electroluminescence of SAG‐InGaN/AlGaN heterostructure by mixed‐source HVPE
Authors: Kim K. H. , Ahn H. S. , Yang M. , Jang K. S. , Hwang S. L. , Choi W. J. , Cho C. R. , Kim S. W. , Honda Y. , Yamaguchi M. , Sawaki N. , Yoo J. , Lee S. M. , Koike M. 
Published: May 2006

AbstractThe AlxGa1–xN layers on GaN/Al2O3 substrates are grown by mixed‐source hydride vapor phase epitaxy (HVPE) at various temperatures of the source zone. We find source zone temperature dependence of the composition x of AlxGa1–xN layers. Te doping as a new attempt and Si doping in obtaining an n‐type AlGaN layers are performed by putting small amount of Te (or Si) into the Ga‐Al source, respectively. In case of Te‐doped AlGaN (x = 0.16), the carrier concentration is varied from 1.1 x 1018 to 8.0 x 1018/cm3, while in case of Si‐doped one, it is varied from 2.0 x 1016 to 1.1 x 1017/cm3. We find the new results that Te doping is more suitable to get a high n‐type concentration by mixed‐source HVPE. InGaN/GaN multiple quantum wells (MQWs) are grown on the selective area growth (SAG)‐Te‐doped AlGaN and SAG‐Si‐doped AlGaN cladding layer by mealorganic chemical vapour deposition (MOCVD), respectively. Furthermore, we investigate the electroluminescence (EL) properties of SAG‐LEDs of two different cladding layers. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of Si on the growth mode of GaN
Authors: von Pezold J. , Oliver R. A. , Kappers M. J. , Bristowe P. D. , Humphreys C. J. 
Published: May 2006

AbstractIn the growth of InGaN on a SiH4‐exposed GaN surface, a change in the growth mode is observed for low SiH4 doses. To help explain this observation the potential energy surface of Ga and N adatoms on a GaN (0001) surface containing an isolated Si atom in the terminating layer was calculated using plane wave density functional theory. The surface Si atom decreases the diffusion barrier of Ga and N adatoms relative to the corresponding diffusion barriers on the ideal GaN (0001) surface. In addition, the adatom binding energies were not significantly affected by the Si surface atom. It was therefore concluded that the observed transition in growth mode of GaN cannot be simply explained by the presence of isolated Si atoms on the GaN surface. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
A Quantum‐Mechanical QSAR Model to Predict the Refractive Index of Polymer Matrices
Authors: Holder Andrew J. , Ye Lin , Eick J. David , Chappelow Cecil C. 
Published: May 2006

AbstractRefractive index (RI) is an important optical property for polymer matrices, especially when the color or tint of the cured material is of interest. This is certainly the case for dental restorative applications. In this work, results are presented for a quantitative–structure activity relationship derived from relevant semiempirical quantum mechanical information. This model predicts the RI for a wide variety of polymer matrices using representative structures of polymers, including resin components of several currently used dental restorative materials. The AM1 semiempirical method was used for calculations due to its speed and general reliability. Several structural subunits of the polymer chains were used for the QSAR analysis, but dimer moieties produced the best results for some 60 polymers. The final QSAR model was composed of a multilinear equation that featured the highest occupied molecular orbital – the lowest unoccupied molecular orbital gap and a polarizability index as the two descriptors best able to account for the variation in the data. The final model had R2=0.963, R2cv=0.959, F=740, and s2=0.0002. Other quality indicators for the correlation and the individual descriptors were within acceptable limits. The presence of electronically related descriptors is encouraging, as these are conceptually tied to the phenomenon of RI. The difference between a theoretically predicted value for poly(propylene oxide) and its monomer was 0.04, as compared to 0.09 from experimental data.
Structural Requirements of Angiotensin I‐Converting Enzyme Inhibitory Peptides: Quantitative Structure‐Activity Relationship Modeling of Peptides Containing 4‐10 Amino Acid Residues
Authors: Wu Jianping , Aluko Rotimi E. , Nakai Shuryo 
Published: May 2006

AbstractModels for angiotensin converting enzyme (ACE) inhibitory peptides with varied lengths are proposed based on results from partial least square regression analysis of the potency of known peptides. Modeling was performed using partial least square regression with inhibitory activity of peptides as the dependent variable (Y) and the physicochemical properties of amino acids as the predictor X matrix. Variable importance in the projection (VIP) analysis of individual amino acid residues at each position revealed that the C‐terminal tetrapeptide residues of long‐chain peptides were more important to their ACE‐inhibitory activity than the C‐terminal tripeptide residues. The most likely preferred amino acid residues starting from C‐terminus are tyrosine and cysteine for the first position, histidine, tryptophan and methionine for the second position with isoleucine, leucine, valine and methionine for the third position, and tryptophan for the fourth position. We concluded that the reported structural requirements of ACE‐inhibitory peptides provide useful information that can be used for the development of more efficacious ACE‐inhibitory peptides.
Critical success factors for software process improvement implementation: an empirical study
Authors: Niazi Mahmood , Wilson David , Zowghi Didar 
Published: May 2006

AbstractIn this article, we present findings from our recent empirical study of the critical success factors (CSFs) for software process improvement (SPI) implementation with 34 SPI practitioners. The objective of this study is to provide SPI practitioners with sufficient knowledge about the nature of issues that play a positive role in the implementation of SPI programmes in order to assist them in effectively planning SPI implementation strategies.Through our empirical study we identified seven factors (higher management support, training, awareness, allocation of resources, staff involvement, experienced staff and defined SPI implementation methodology) that are generally considered critical for successfully implementing SPI. We also report on a literature survey of CSFs that impact SPI and identify six factors (senior management commitment, staff involvement, staff time and resources, training and mentoring, creating process action teams and reviews). We compared our empirical study results with the literature and confirmed the factors identified in the literature, and also identified two new CSFs (SPI awareness and defined SPI implementation methodology) that were not identified in the literature. Finally, we analyzed the CSFs identified by different groups of practitioners and found that they are aware of what is imperative for the successful implementation of SPI programmes. Copyright © 2006 John Wiley & Sons, Ltd.
Treatment of Wilms’ tumor in children
Authors: Johnson Dale G. 
Published: May 2006

AbstractDramatic advances in management of Wilms’ tumor have been achieved through a multidisciplinary approach to treatment involving surgery, radiotherapy, and combination chemotherapy. Recent cooperative clinical studies of nationwide scope have permitted the use of randomized, prospective, comparative trials designed to answer some of the perplexing questions in tumor management. For group I patients with localized disease, a survival rate of 97% has been achieved. Significant clinical data have justified the elimination of postoperative irradiation and its deleterious long‐term side effects in group I children under 2 years of age, and current studies replacing radiotherapy with combination drug therapy will probably allow the elimination of radiotherapy for all group I patients. The combination of dactinomycin‐vincristine (AMD‐VCR) has proven superior to single‐agent treatment, and in group II and III patients with local tumor extension, survival rates have reached 86%. Most remarkable is the achievement of an 83% survival rate at 2 years in group IV patients with metastatic disease at the time of diagnosis, since survival of this type of patient before chemotherapy was nil. The newly recognized histologic grading of “unfavorable” and “favorable” prognostic types of tumor should stimulate refinement of therapy and further improvement in survival by application of more or less aggressive treatment, as appropriate. The current survival rate of 87% in patients with bilateral tumors is also remarkable and underscores the need for flexibility and an understanding of tumor biology for successful clinical management.