bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Biphenanthrenyls and Role of C−H···X Noncovalent Interactions in Conformational Control
Authors: Sharon Ashoke , Maulik Prakas R. , Vithana Champika , Ohashi Yuji , Ram Vishnu Ji 
Published: February 2004

AbstractA convenient synthesis of the 1,2′‐biphenanthrenyls 4a−c,f, 1,3′‐biphenanthrenyls 4d,e, thiabiphenanthrenyl 4g, the benzo[h]chromen‐2‐ylideneacetonitrile 5a and the methyl benzo[h]chromen‐2‐ylideneacetate 5b through carbanion‐induced ring transformation of 2H‐pyran‐2‐ones 1 or 2 and the 1‐naphthalenone 3a or thiochroman‐4‐one 3b separately is described. The structures of the biphenanthrenyls 4b and 4c have been confirmed by single‐crystal X‐ray diffraction. The conformations of 2b, 4b, 4c and 6 have also been studied to establish the role of C−H···X interaction in conformational control. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Cover Picture: Solvent‐Dependent Competitive Rearrangements of Cyclic Tertiary Propargylamine N‐Oxides (Eur. J. Org. Chem. 4/2004)
Authors: Szabó Anna , Galambos‐Faragó Ágnes , Mucsi Zoltán , Timári Géza , Vasvári‐Debreczy Lelle , Hermecz István 
Published: February 2004

AbstractThe cover picture shows the energy profile calculated by ab initio methods of the competing reactions from N‐propargylmorpholine N‐oxide in protic medium: the well‐known Meisenheimer rearrangement to O‐allenylhydroxylamine and the recently revealed rearrangement to enamino aldehyde. Kinetic measurements in different alcohols, in agreement with the ab initio studies, afforded information on the structures of the transition states involved in the rate‐determining and product‐distribution‐determining steps, supporting our assumption on the mechanism of these reactions. Details are discussed in the article by I. Hermecz et al. on p. 687 ff.
Time variation in the tail behavior of Bund future returns
Authors: Werner Thomas , Upper Christian 
Published: February 2004

AbstractThe literature on the tail behavior of asset prices focuses mainly on the foreign exchange and stock markets,
with only a few articles dealing with bonds or bond futures. The present article addresses this omission. It
focuses on three questions using extreme value analysis: (a) Does the distribution of Bund future
returns have heavy tails? (b) Do the tails change over time? (c) Does the tail
index provide information that is not captured by a standard VaR approach? The results are as follows:
(a) The distribution of high‐frequency returns of the Bund future is indeed characterized by
heavy tails. The tails are thinner for lower frequencies, but remain significantly heavy even for daily data.
(b) There are statistically significant breaks in the tails of the return distribution. (c)
The likelihood of extreme price movements suggested by extreme value theory differs from that obtained by standard
risk measures. This suggests that the tail index does indeed provide information not contained in volatility
measures. © 2004 Wiley Periodicals, Inc. Jrl Fut Mark 24:387–398, 2004
Properties and Reactions of Substituted 1,2‐Thiazetidine 1,1‐Dioxides: Chiral Mono‐ and Bicyclic 1,2‐Thiazetidine 1,1‐Dioxides from α‐Amino Acids
Authors: Meinzer Alexandra , Breckel Andrea , Thaher Bassam Abu , Manicone Nico , Otto Hans‐Hartwig 
Published: February 2004

AbstractNew chiral mono‐ and bicyclic β‐sultams, valuable building blocks for drug synthesis, have been prepared from L‐Ala, L‐Val, L‐Leu, L‐Ile, L‐Phe, L‐Cys, L‐Ser, L‐Thr, and D‐penicillamine by transformation of the COOH group into a methylsulfonyl chloride function, followed by cyclization under basic conditions. Selected properties, derivatives, and reactions of the β‐sultams are described.
Electrophoretic karyotype of two Micromucor species
Authors: Nagy Ágnes , Pesti Miklós , Galgóczy László , Vágvölgyi Csaba 
Published: February 2004

AbstractElectrophoretic karyotype analysis was applied to obtain information on the organisation and intrageneric variability of the nuclear genome in three Micromucor isolates of two different species (M. isabellina and M. ramanniana). A protoplast formation protocol, conditions for the preparation of highly‐intact chromosome‐size DNA molecules and for the separation of DNA molecules were established. The chromosomal banding patterns revealed substantial variability among the isolates: 11 to 14 chromosomal mobility groups were resolved. The DNA in the Micromucor chromosomes were rather small; their estimated sizes were calculated to be between 2.60 and 0.4 Mb. Using Saccharomyces cerevisiae and Schizosaccharomyces pombe as size standard, the minimum total genome sizes were estimated to be between 24.19 and 24.9 Mb.
Glivenko like theorems in natural expansions of BCK‐logic
Authors: Cignoli Roberto , Torrens Torrell Antoni 
Published: February 2004

AbstractThe classical Glivenko theorem asserts that a propositional formula admits a classical proof if and only if its double negation admits an intuitionistic proof. By a natural expansion of the BCK‐logic with negation we understand an algebraizable logic whose language is an expansion of the language of BCK‐logic with negation by a family of connectives implicitly defined by equations and compatible with BCK‐congruences. Many of the logics in the current literature are natural expansions of BCK‐logic with negation. The validity of the analogous of Glivenko theorem in these logics is equivalent to the validity of a simple one‐variable formula in the language of BCK‐logic with negation. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Meshless analysis of potential problems in three dimensions with the hybrid boundary node method
Authors: Zhang Jianming , Tanaka Masataka , Matsumoto Toshiro 
Published: February 2004

AbstractCombining a modified functional with the moving least‐squares (MLS) approximation, the hybrid boundary node method (Hybrid BNM) is a truly meshless, boundary‐only method. The method may have advantages from the meshless local boundary integral equation (MLBIE) method and also the boundary node method (BNM). In fact, the Hybrid BNN requires only the discrete nodes located on the surface of the domain.The Hybrid BNM has been applied to solve 2D potential problems. In this paper, the Hybrid BNM is extended to solve potential problems in three dimensions. Formulations of the Hybrid BNM for 3D potential problems and the MLS approximation on a generic surface are developed. A general computer code of the Hybrid BNM is implemented in C++. The main drawback of the ‘boundary layer effect’ in the Hybrid BNM in the 2D case is circumvented by an adaptive face integration scheme. The parameters that influence the performance of this method are studied through three different geometries and known analytical fields. Numerical results for the solution of the 3D Laplace's equation show that high convergence rates with mesh refinement and high accuracy are achievable. Copyright © 2004 John Wiley & Sons, Ltd.
Dual boundary element method for anisotropic dynamic fracture mechanics
Authors: Albuquerque E. L. , Sollero P. , Aliabadi M. H. 
Published: February 2004

AbstractIn this work, the dual boundary element method formulation is developed for effective modelling of dynamic crack problems. The static fundamental solutions are used and the domain integral, which comes from the inertial term, is transformed into boundary integrals using the dual reciprocity technique. Dynamic stress intensity factors are computed from crack opening displacements. Comparisons are made with quasi‐isotropic as well as anisotropic results, using the sub‐region technique. Several examples are presented to assess the accuracy and efficiency of the proposed method. Copyright © 2004 John Wiley & Sons, Ltd.
Coupling recognition of the structure and parameters of non‐linear constitutive material models using hybrid evolutionary algorithms
Authors: Feng Xia‐Ting , Yang Chengxiang 
Published: February 2004

AbstractThe structure of the non‐linear constitutive models is a key to control non‐linear behaviours of materials. Because the non‐linear mechanical mechanism is not clearly understood in most cases, it is very difficult to assume the structure of the model in advance. The recognition of the structure of the model from experimental results can help understanding of the mechanism. This recognition is a dynamic search problem being highly multimodal, multi‐variable with high order, and needing a large parameter space. How to obtain a global optimum solution is a key to this problem. In this paper, a hybrid evolutionary algorithm is proposed for coupling recognition of the structure of the non‐linear constitutive material model and its coefficients in global space using global response information, e.g. load vs deflection data, obtained from the structural test. Genetic programming is used to recognize the structure of the non‐linear stress–strain relationship without any assumption in advance and the genetic algorithm is then used to recognize its coefficients. The non‐linear stress–strain relationship thus found can not only satisfy the dynamic change in its structure but also its variables and coefficients. Non‐linear finite element analysis is used to transfer the load–deflection information to the stress–strain data. The potential of the proposed method is demonstrated by applying it to the macro‐mechanical modelling of the non‐linear behaviour of composite materials. A non‐linear material model for the unidirectional ply is recognized by using experimental data of a lamina plate [(±45)6]s. The obtained non‐linear constitutive model gave good predictions in coincidence with the non‐linear behaviours of the [(±30)6]s, [(0/±45)3]s and [(0/±45)4]s plates. The results indicate that the coupling non‐linear constitutive model of the structure and its coefficients can identify the model which the traditional constitutive model theory is unable to recognize. Copyright © 2004 John Wiley & Sons, Ltd.
Structural developments in synthetic rubbers during uniaxial deformation by in situ synchrotron X‐ray diffraction
Authors: Toki Shigeyuki , Sics Igors , Hsiao Benjamin S. , Murakami Syozo , Tosaka Masatoshi , Poompradub Sirilux , Kohjiya Shinzo , Ikeda Yuko 
Published: February 2004

AbstractThe molecular orientation and strain‐induced crystallization of synthetic rubbers—polyisoprene rubber, polybutadiene rubber, and butyl rubber [poly(isobutylene isoprene)]—during uniaxial deformation were studied with in situ synchrotron wide‐angle X‐ray diffraction. The high intensity of the synchrotron X‐rays and the new data analysis method made it possible to estimate the mass fractions of the strain‐induced crystals and amorphous chain segments in both the oriented and unoriented states. Contrary to the conventional concept, the majority of the molecules (50–75%) remained in an unoriented amorphous state at high strains. Each synthetic rubber showed a different behavior of strain‐induced crystallization and molecular orientation during extension and retraction. Our results confirmed the occurence of strain‐induced networks in the synthetic rubbers due to the inhomogeneity of the crosslink distribution. The strain‐induced networks containing microfibrillar crystals and oriented amorphous tie chains were responsible for the ultimate mechanical properties. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 956–964, 2004
Crystallization and morphology of poly(vinylidene fluoride)/poly(3‐hydroxybutyrate) blends. II. Morphology and crystallization kinetics by time resolved X‐ray scattering
Authors: Liu Jieping , Jungnickel Bernd‐J. 
Published: February 2004

AbstractThe development of the morphology in poly(vinylidene fluoride)/poly(3‐hydroxybutyrate) (PVDF/PHB) blends upon isothermal and anisothermal crystallization is investigated by time‐resolved small‐ and wide‐angle X‐ray scattering. The components are completely miscible in the melt but crystallize separately; they crystallize stepwise at different temperatures or sequentially with isothermal or anisothermal conditions, respectively. The PVDF crystallizes undisturbed whereas PHB crystallizes in a confined space that is determined by the existing supermolecular structure of the PVDF. The investigations reveal that composition inhomogeneities may initially develop in the remaining melt or in the amorphous phases of the PVDF upon crystallization of that component. The subsequent crystallization of the PHB depends on these heterogeneities and the supermolecular structure of PVDF (dendritically or globularly spherulitic). PHB may form separate spherulites that start to grow from the melt, or it may develop “interlocking spherulites” that start to grow from inside a PVDF spherulite. Occasionally, a large number of PVDF spherulites may be incorporated into PHB interlocking spherulites. The separate PHB spherulites may intrude into the PVDF spherulites upon further growth, which results in “interpenetrating spherulites.” Interlocking and interpenetrating are realized by the growth of separate lamellar stacks (“fibrils”) of the blend components. There is no interlamellar growth. The growth direction of the PHB fibrils follows that of the existing PVDF fibrils. Depending on the distribution of the PHB molecules on the interlamellar and interfibrillar PVDF regions, the lamellar arrangement of the PVDF may contract or expand upon PHB crystallization and the adjacent fibrils of the two components are linked or clearly separated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 974–985, 2004
Effects of the copolymer microstructure on the morphology of polyethylene–poly(ethylene‐co‐α‐olefin) blends
Authors: Tabtiang Arunee , Phochalam Noree , Venables Richard 
Published: February 2004

AbstractThe effects of the copolymer microstructure on the morphology evolution in polyethylene/poly(ethylene‐co‐α‐olefin) blends were investigated. Microscopy revealed that the melt‐phase morphology, inferred from the solid‐state morphologies of annealed and quenched samples, was strongly affected by the copolymer structure, that is, the branch content and branch length. Higher molecular weight α‐olefin comonomer residues and residue contents in the copolymers led to faster coarsening of the morphology. The molecular weight of the polyethylene and the copolymers affected the coarsening rates of the morphology, principally through its influence on the melt viscosity. The effects of the molecular weight were largely explained by the normalization of the coarsening rate data with respect to the thermal energy and zero‐shear‐rate viscosity. Thus, the effect of the molecular weight on the compatibility of the blends was much smaller than the effects of the branch length and branch number. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 965–973, 2004
Ellipsometry study of the photo‐oxidation of poly[(2‐methoxy‐5‐hexyloxy)‐ p‐phenylenevinylene]
Authors: Bianchi R. F. , Balogh D. T. , Tinani M. , Faria R. M. , Irene E. A. 
Published: February 2004

AbstractPoly(p‐phenylenevinylene) (PPV) and its derivatives exhibit strong luminescence, being serious candidates to be used as active layers in organic light‐emitting diodes. However, the structural degradation caused by photo‐oxidation is an obstacle for commercial applications of such materials. Here, we show that spectroscopy ellipsometry is a useful technique to investigate the photo‐oxidation of poly[(2‐methoxy‐5‐hexyloxy)‐p‐phenylenevinylene] (MH‐PPV), a PPV derivative, which emits a red color light. Spectroscopy ellipsometry enables determination of the complex dielectric function—ϵ*(E)—of MH‐PPV thin‐layer films exposed to air, in the 2.1–4.2 eV energy range, as a function of the light exposure time (te). By using the Lorentz model to fit the experimental ϵ*(E) curves, it was inferred that the interactions among polymeric chains increase with te. From ϵ*(E), it is also possible to obtain the complex refractive index, N*(E) = n + ik. At higher energies (where k ≪ n), n increases from 1.32 to 1.40 with the photo‐oxidation progress. The behavior of n was investigated by using the Lorenz–Lorentz equation, taking into account the contribution for n by the chromophores of MH‐PPV. The effect of photo‐oxidation, mainly due to the replacement of vinyl CC by the ketone CO bonds, is confirmed by Fourier transform infrared measurements, an effect that reduces the average effective polymer conjugation length. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1033–1041, 2004
Miscibility, specific interactions, and self‐assembly behavior of phenolic/polyhedral oligomeric silsesquioxane hybrids
Authors: Lee Yuan‐Jyh , Kuo Shiao‐Wei , Huang Wu‐Jang , Lee Hung‐Yen , Chang Feng‐Chih 
Published: February 2004

AbstractThe miscibility of a phenolic resin with polyhedral oligomeric silsesquioxane (POSS) hybrids and the specific interactions between them were investigated with Fourier transform infrared (FTIR) spectroscopy and wide‐angle X‐ray diffraction (WAXD). An analysis of the morphology and microstructure was performed with polarized optical microscopy and atomic force microscopy (AFM). The interassociation equilibrium constant between the phenolic resin and POSS (38.7) was lower than the self‐association equilibrium constant of pure phenolic (52.3) according to the Painter–Coleman association model. This result indicated that POSS was partially miscible with the phenolic resin. A polarized optical microscopy image of a phenolic/POSS hybrid material (20 wt % POSS) indicated that the crystals of POSS were arranged evenly in the phenolic matrix; the self‐assembled array of POSS crystals was also confirmed by AFM. This phenomenon was consistent with the FTIR spectroscopy and WAXD analyses. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1127–1136, 2004
Structure‐property relationships in exfoliated polyisoprene/clay nanocomposites
Authors: Jeon H. S. , Rameshwaram J. K. , Kim G. 
Published: February 2004

AbstractStructure‐property relationships in exfoliated polyisoprene (PI)/clay nanocomposites have been studied as a function of the clay concentration with rheometry, X‐ray diffraction, small‐angle X‐ray scattering, and transmission electron microscopy. The results presented here indicate that the interlayer spacing of layered silicates increases from 2 to at least approximately 14 nm because of the penetration of polymer molecules into the spacing between the silicate layers. The average aspect ratio (width/thickness) of the dispersed nanoplates is also estimated to be at least approximately 80. Additionally, the storage modulus of the nanocomposite exhibits frequency‐independent pseudo‐solidlike behavior above the percolation threshold [volume fraction of clay at the percolation threshold (ϕp) = 0.02] and shows large enhancements (up to approximately six orders of magnitude) in comparison with the storage modulus of PI when the volume fraction of clay (ϕ) is greater than ϕp. For the shear‐aligned PI/clay nanocomposites, an increase in the storage modulus with shear alignment is observed at ϕ < ϕp, whereas a decrease in the storage modulus is observed for ϕ > ϕp. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 1000–1009, 2004
A comparison of corrugated boxes and reusable plastic containers for mango distribution
Authors: Chonhenchob Vanee , Singh S. Paul 
Published: February 2004

AbstractThis paper evaluated various shipping packages (corrugated boxes and reusable plastic crates) on their protective performance based on bruising and heat transfer characteristics for shipping and handling mangoes. The effect of maturity stage on bruise susceptibility of mangoes was also studied. Mangoes were evaluated for bruise damage after subjecting to shipping and vibration tests. The results indicated that proper shipping containers and cushioning methods significantly reduces bruising in mangoes. Design features of shipping containers, such as physical protection and pre‐cooling characteristics, should be considered when shipping mangoes. The methods from this study can be used for selecting proper packaging to reduce damage of mangoes and other sensitive tropical fruits during distribution. Copyright © 2003 John Wiley & Sons, Ltd.
Plasma‐aktivierte Bedampfung von flexiblen Materialien. Plasma‐activated vapour deposition on flexible substrates
Authors: Günther Steffen 
Published: February 2004

AbstractDie Vakuumbeschichtung von flexiblen Materialien, insbesondere Kunststofffolien, wird weltweit eingesetzt, um deren Oberflächeneigenschaften für bestimmte Anwendungen zu verändern.Gewünschte physikalische Eigenschaften, wie z. B. Dichte, Härte, Brechungsindex und Permeation, sind dabei in starkem Maße von der Mikrostruktur der aufgebrachten Schicht abhängig. Wie in diesem Artikel gezeigt werden soll, wird durch die Anwendung plasmaaktivierter Verfahren diese Mikrostruktur entscheidend verbessert.Am Fraunhofer Institut für Elektronenstrahl‐ und Plasmatechnik (FEP) wurde ein Verfahren zur Plasmaaktivierung bei der Hochratebeschichtung entwickelt. Das Verfahren basiert auf der Hohlkathoden‐Bogenentladung. Die Plasmaquellen sind für hochproduktive Bandbedampfungsanlagen mit Schiffchenverdampfern oder Elektronenstrahlverdampfern geeignet.
Wirtschaftliche Anwendung von Mikrowellen‐Plasmen vom mittleren bis Atmosphärendruck. Economic utilisation of microwave excited plasma in medium to atmospheric pressure
Authors: Spitzl Ralf , Sung‐Spitzl Hildegard 
Published: February 2004

AbstractEs wird ein Überblick über die Möglichkeiten von Plasma Prozessen im mittleren bis Atmosphärendruck gegeben und im Kontext von Produktanwendungen diskutiert.Hohe Prozessgeschwindigkeit und Verlässlichkeit sind die wichtigsten Faktoren für industrielle Anwendungen. Das Mittel‐ bis Atmosphärendruckplasma ist in diesem Zusammenhang ein nützliches und wertvolles Werkzeug. Seine Entwicklung und Markteinführung stellt einen großen Fortschritt dar. Die in diesem Druckbereich betriebene CYRANNUS® Plasmaquelle basiert auf dem Konzept eines zylindrischen Resonators mit ringförmigen Schlitzen (engl.: cylindrical resonator with annular slots). Die Parameter Gas‐ und Flussdynamik können kontrolliert werden und führen zu weiteren Verbesserungen der Anlagen‐ und Prozessgestaltung.Nutzt man konsequent die Vorteile der Mitteldruck‐Plasmaprozesse, führt dies zu einer neuen Gestaltung der Anlagen und des Materialflusses. Die In‐line/On‐line Behandlung von 3‐D‐Werkstücken wird sehr effizient und ermöglicht konkurrenzfähige Plasmaprozesse für die Massenproduktion.Als weitere Möglichkeit der Produktivitätssteigerung der CYRANNUS® Technologie wird der Einsatz im Bereich der Diamantbeschichtungen genutzt. Hierbei ist die Vergrößerung des Plasmas entscheidend, um Diamantschichten im wirtschaftlich attraktiven Rahmen herzustellen. Eine Besonderheit der CYRANNUS® Einkopplung ist die mehrfache Skalierungsmöglichkeit, die ohne Einschränkung des Druckbereiches möglich ist (Abb. 1).