bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Use of the Indentation Test for Studying the Solidification Behaviour of Different Semicrystalline Polymers during Injection Molding
Authors: La Carrubba Vincenzo , Gabriëlse Wouter , Piccarolo Stefano 
Published: October 2005

AbstractSummary: An in‐line method for monitoring the solidification process during injection molding of semicrystalline polymers (demonstrated previously in J. Appl. Polym. Sci. 2003, 89, 3713) is based on a simple device, where an additional ejector pin is pushed on the injection molded part at different times during the solidification phase. The ‘indentation depth profile’, i.e., residual deformation as a function of time, was obtained and allowed to determine the evolution of the solidification front in the mold as a function of the cooling time. The present work shows the reliability and the powerfulness of the aforementioned method for a large variety of different semicrystalline polymers (PET, PBT, polyamide‐6 PA6, isotactic poly(propylene) iPP) characterized also by different molecular weight and/or nucleating agents. The results show that the indentation test may be considered as a ‘predictive’ tool to qualitatively and quantitatively compare the solidification process of different polymers and polymer grades during injection molding.Comparison of the solid front propagation during injection molding of different materials.imageComparison of the solid front propagation during injection molding of different materials.
Solvent Controlled Multi‐Morphological Self‐Assembly of Amphiphilic Graft Copolymers
Authors: Zhang Jian Xiang , Qiu Li Yan , Zhu Kang Jie 
Published: October 2005

AbstractSummary: Amphiphilic graft polyphosphazenes (EtTrp/PNIPAm‐PPP) with different mole ratios of hydrophobic groups to hydrophilic segments were synthesized by ring‐opening polymerization and subsequent substitution reactions. The self‐assembly behavior of these graft copolymers was studied in detail by TEM, SEM, CLSM, and AFM. Depending on the copolymer composition and common organic solvent employed in dialysis process, supramolecular aggregates ranging from network, nanospheres, high‐genus particles to macrophage‐like aggregates were produced with graft copolymers.
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Synthesis, Optical, and Electrochemical Properties of the High‐Molecular‐Weight Conjugated Polycarbazoles
Authors: Fu Yaqin , Bo Zhishan 
Published: October 2005

AbstractSummary: A kind of novel dibromocarbazole monomer bearing three alkyl chains was prepared. Two strategies were developed to improve the solubility and molecular weight of carbazole polymers. One was the polymerization of N‐octyl‐2,7‐bis(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)carbazole with the alkylated dibromocarbazole. Another one was the polymerization of N‐octyl‐2,7‐bis(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)carbazole with N‐octyl‐3,6‐dibromocarbazole. All the polymerizations were carried out under palladium‐catalyzed Suzuki polycondensation (SPC) conditions. Through using carbazole monomer bearing three alkyl chains to polymerize, we have successfully boosted the number‐average molecular weight of 2,7‐linked carbazole polymers from not more than 5 to 67 kDa. The high‐molecular‐weight polymers were obtained in high yields and displayed good solubility in common organic solvents. Their optical, electrochemical, and thermal properties were also reported.Preparation of carbazole polymers by Suzuki polycondensation.magnified imagePreparation of carbazole polymers by Suzuki polycondensation.
Effects of Catalyst Isoquinoline in Polymerization Process on the Aggregation Structures of Polyimide in Solution
Authors: Liu Xiangyang , Yang Jin , Guo Linghong , Gu Yi 
Published: October 2005

AbstractSummary: A thermoreversible gel or a dendritic crystal has been obtained in a novel polyimide solution at low temperature, depending on the approach taken to add the isoquinoline catalyst during the polymerization process. By adding the isoquinoline at the beginning of polymerization, two kinds of layer structures in the gel are developed. However, by adding the isoquinoline after the polymerization has been carried out for one hour, a perfect dendritic crystalline structure is gradually developed in the polymerization solution.PLM photographs of the obtained polyimide crystals.magnified imagePLM photographs of the obtained polyimide crystals.
Electrostatically Dissipative Polystyrene Nanocomposites containing Copper Nanowires
Authors: Gelves Genaro A. , Sundararaj Uttandaraman , Haber Joel A. 
Published: October 2005

AbstractSummary: A scalable synthesis of copper nanowires by alternating current electrodeposition into porous aluminium oxide was used to produce multigram quantities of 16 nm diameter by >2 µm long nanowires. Polystyrene nanocomposites were prepared by solution processing. The composites containing unpassivated nanowires were non‐uniformly dispersed and showed electrical percolation at ≈2 vol.‐% Cu loading, while the composites containing HSC18H37‐passivated nanowires were uniformly dispersed, but remained resistive up to at least 10 vol.‐% Cu loading.Copper nanowires prepared by alternating current electrodeposition into porous aluminium oxide templates.magnified imageCopper nanowires prepared by alternating current electrodeposition into porous aluminium oxide templates.
Crosslinkable Vesicles Self‐Assembled by Amphiphilic Hyperbranched Polyester
Authors: Zou Jianhua , Ye Xiaodong , Shi Wenfang 
Published: October 2005

AbstractSummary: Amphiphilic hyperbranched polyester (H20‐AM) with methacrylate end groups was synthesized based on hyperbranched aliphatic polyester (Boltorn™ H20). Narrow‐dispersed crosslinkable vesicles were obtained by dissolving H20‐AM in water, and characterized by laser light scattering and TEM. The hollow structural vesicle is composed of around 350 H20‐AM molecules, having a radius of around 40 nm and $\overline M _{\rm w}$ of 1.9 × 106 g · mL−1. The vesicles were fixed by crosslinking of methacrylate groups to form shape‐persistent structures.TEM images of the crosslinked vesicles at lower magnification.magnified imageTEM images of the crosslinked vesicles at lower magnification.
Novel Polymer Electrolyte Membrane, Based on Pyridine Containing Poly(ether sulfone), for Application in High‐Temperature Fuel Cells
Authors: Pefkianakis Elefterios K. , Deimede Valadoula , Daletou Maria K. , Gourdoupi Nora , Kallitsis Joannis K. 
Published: October 2005

AbstractSummary: Novel poly(aryl ether sulfone) copolymers containing 2,5‐biphenylpyridine and tetramethyl biphenyl moieties were synthesized by polycondensation of 4‐fluorophenyl sulfone with 2,5‐(4′,4″ dihydroxy biphenyl)pyridine and tetramethyl biphenyl diol. Copolymers with different molecular weights and different monomer compositions were obtained. These copolymers exhibit excellent film‐forming properties, mechanical integrity, and high modulus up to 250 °C, high glass transition temperatures (above 280 °C) as well as high thermal stability up to 400 °C. In addition to the above properties required for PEMFC application, this novel material shows high oxidative stability and acid doping ability, enabling proton conductivity in the range of 10−2 S · cm−1 above 130 °C.Synthesis of copolymers with high acid uptake and ionic conductivity.magnified imageSynthesis of copolymers with high acid uptake and ionic conductivity.
The impact of institutions on entrepreneurial activity
Authors: Stephen Frank H. , Urbano David , van Hemmen Stefan 
Published: October 2005

AbstractThis paper presents an empirical analysis of the factors which promote entrepreneurial activity across a number of transition, developing and developed countries. It produces results which highlight the importance of institutions in promoting entrepreneurial activity. This work is part of an on‐going research project on the relationship between the legal system and factors which influence economic development. In particular, it has been shown that legal rules protecting creditors and investors influence the size of financial markets which in turn influence economic development. Our paper thus extends the analysis of the impact of institutions beyond that previously established to demonstrate its influence on another driver of economic development. Copyright © 2005 John Wiley & Sons, Ltd.
Enron, corporate governance and deterrence
Authors: Dnes Antony W. 
Published: October 2005

AbstractIn this paper, I investigate the lessons from the financial scandals surrounding companies like Enron and WorldCom. These companies have generated concerns leading to the legal reform of corporate governance in America, and to the revision of voluntary, self‐regulatory codes in Europe. The passage of time since the Enron debacle shows that critics were too quick to criticize, since the required adjustments have more the nature of minor adjustments to regulations. Copyright © 2005 John Wiley & Sons, Ltd.
Disclosure level and cost of equity capital: evidence from the banking industry
Authors: Poshakwale Sunil , Courtis John K. 
Published: October 2005

AbstractThe impact of voluntary disclosures on cost of equity capital is of significant interest to investors and managers. Using a disclosure scoring model this association is examined for 135 banks from Europe, North America and Australia. After controlling for the cross‐sectional variation in beta, firm size, price to book value and price to earnings ratios, the study found that higher disclosure levels are associated with a reduction in cost of equity capital. Disclosures about risk management practices seem to most influence the reduction in the cost of equity capital. European banks show greater reduction in the cost of equity capital from improved disclosures compared to their non‐European counterparts. Copyright © 2005 John Wiley & Sons, Ltd.
Corporate governance and development: the case of China
Authors: Liu Sean 
Published: October 2005

AbstractThere has been a growing interest in corporate governance in China in recent years. This article assesses some of the key moves by the Chinese authorities aimed at developing corporate governance in China. Many problems persist that are typical of systems that fail to protect shareholder interests, and we can detect political influence in the two‐tiered board system. Privatization has focused attention on the rules governing enterprise operations. The new legal framework of company law still leaves much scope for developing corporate governance at the level of the enterprise. Copyright © 2005 John Wiley & Sons, Ltd.
Corporate governance, ownership structure and corporate efficiency: the case of Ukraine
Authors: Zheka Vitaliy 
Published: October 2005

AbstractThe goal of this paper is to examine the effects of different ownership structures and of the quality of corporate governance on the Farrell measure of efficiency. Data Envelopment Analysis and Limited Dependent Variable Estimations are applied to the set of Ukrainian joint‐stock companies listed on the main Ukrainian stock exchange, First Securities Trading System. Domestic ownership of the organization is found to enhance efficiency the most, whereas managerial ownership has a detrimental effect on efficiency. Foreign owned firms are relatively inefficient; however foreign ownership is found to have a positive and significant effect on corporate governance quality. Concentrated ownership rights (including state ownership) improve efficiency, possibly reflecting country‐specific factors. The quality of corporate governance is found to have a positive impact on the efficiency of domestically owned firms. Copyright © 2005 John Wiley & Sons, Ltd.
The existence of positive solutions to a non‐local singular boundary value problem
Authors: O'Regan Donal , Staněk Svatoslav 
Published: October 2005

AbstractWe consider the non‐local singular boundary value problem

where q ∈ C0([0,1]) and f, h ∈ C0((0,∞)), limf(x)=−∞, limh(x)=∞. We present conditions guaranteeing the existence of a solution x ∈ C1([0,1]) ∩ C2((0,1]) which is positive on (0,1]. The proof of the existence result is based on regularization and sequential techniques and on a non‐linear alternative of Leray–Schauder type. Copyright © 2005 John Wiley & Sons, Ltd.
Dispersive estimate for the Schrödinger equation with point interactions
Authors: D'Ancona Piero , Pierfelice Vittoria , Teta Alessandro 
Published: October 2005

AbstractWe consider the Schrödinger operator in ℝ3 with N point interactions placed at Y=(y1,…,yN), yj ∈ ℝ3, of strength α=(α1,…,αN), αj ∈ ℝ. Exploiting the spectral theorem and the rather explicit expression for the resolvent we prove the (weighted) dispersive estimate for the corresponding Schrödinger flow.In the special case N=1 the proof is directly obtained from the unitary group which is known in closed form. Copyright © 2005 John Wiley & Sons, Ltd.
An existence result for a two‐phase Stefan problem arising in metal casting
Authors: Bermúdez A. , Otero M. V. 
Published: October 2005

AbstractWe present a model arising from the thermal modelling of two metal casting processes. We consider an enthalpy formulation for this two‐phase Stefan problem in a time varying three‐dimensional domain and consider convective heat transfer in the liquid phase. Then, we introduce a weak formulation in a fixed domain, by means of a suitable transformation. Existence of solution is obtained by applying an abstract theorem. The proof of this theorem is done by taking an implicit discretization in time together with a regularization. By passing to the limit in the regularization parameter and in the time step, we obtain the existence of solution of the continuous problem. Copyright © 2005 John Wiley & Sons, Ltd.
Approximate source conditions in Tikhonov–Phillips regularization and consequences for inverse problems with multiplication operators
Authors: Hofmann Bernd 
Published: October 2005

AbstractThe object of this paper is threefold. First, we investigate in a Hilbert space setting the utility of approximate source conditions in the method of Tikhonov–Phillips regularization for linear ill‐posed operator equations. We introduce distance functions measuring the violation of canonical source conditions and derive convergence rates for regularized solutions based on those functions. Moreover, such distance functions are verified for simple multiplication operators inL2(0, 1). The second aim of this paper is to emphasize that multiplication operators play some interesting role in inverse problem theory. In this context, we give examples of non‐linear inverse problems in natural sciences and stochastic finance that can be written as non‐linear operator equations inL2(0, 1), for which the forward operator is a composition of a linear integration operator and a non‐linear superposition operator. The Fréchet derivative of such a forward operator is a composition of a compact integration and a non‐compact multiplication operator. If the multiplier function defining the multiplication operator has zeros, then for the linearization an additional ill‐posedness factor arises. By considering the structure of canonical source conditions for the linearized problem it could be expected that different decay rates of multiplier functions near a zero, for example the decay as a power or as an exponential function, would lead to completely different ill‐posedness situations. As third we apply the results on approximate source conditions to such composite linear problems inL2(0, 1) and indicate that only integrals of multiplier functions and not the specific character of the decay of multiplier functions in a neighbourhood of a zero determine the convergence behaviour of regularized solutions. Copyright © 2005 John Wiley & Sons, Ltd.
Novel organic–inorganic hybrid materials from renewable resources: Hydrosilylation of fatty acid derivatives
Authors: Lligadas G. , Callau L. , Ronda J. C. , Galià M. , Cádiz V. 
Published: October 2005

AbstractNovel hybrid organic–inorganic materials were prepared from 10‐undecenoyl triglyceride and methyl 3,4,5‐tris(10‐undecenoyloxy)benzoate via hydrosilylation. 1,4‐Bis(dimethylsilyl)benzene, tetrakis(dimethylsilyloxy)silane, and 2,4,6,8‐tetramethylcyclotetrasiloxane were used as crosslinkers. The hydrosilylation reaction was catalyzed by Karstedt's catalyst [Pt(0)–divinyltetramethyldisiloxane complex]. The networks were structurally characterized by Fourier transform infrared spectroscopy, 13C NMR, and 29Si magic‐angle‐spinning NMR. The thermal properties of these hybrids were studied with differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis. The obtained materials showed good transparency and promising properties for optical applications. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6295–6307, 2005
Polymers from a levopimaric acid–acrylonitrile Diels–Alder adduct: Synthesis and characterization
Authors: Bicu Ioan , Mustata Fanica 
Published: October 2005

AbstractThe Diels–Alder adduct of levopimaric acid with acrylonitrile was efficiently prepared from resin acids. Excellent addition reaction yields (ca. 95%) were obtained. The adduct was converted into polyamides by polycondensation with diamines. When the same adduct was subjected to a dehydrodecarboxylation reaction, a novel ketone dinitrile derivative was obtained. This trifunctional product was also converted into polyamides by polycondensation with diamines. When the ketone dinitrile was hydrolyzed in the presence of alkalies and the reaction product was chlorinated, a ketone diacid chloride was obtained. A polyester was synthesized by the polycondensation of the diacid chloride with a diol. The structures of the Diels–Alder adduct, ketone dinitrile derivative, ketone diacid chloride, and polymers were established by means of elemental analysis, IR and NMR spectroscopy, and molecular weight determinations. Both the polyamides and the polyester were low‐molecular‐weight polymers soluble in polar solvents. The thermal behavior of the monomers and polymers was evaluated by thermogravimetric analysis. The thermal studies showed that the polymers were fairly thermostable substances, except the polyester, which appeared to be a substance with good thermal stability. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6308–6322, 2005
Preparation of new π‐conjugated polypyrroles by organometallic polycondensations. Synthesis of N‐BOC (t‐butoxycarbonyl) and N‐phenylethynyl polymers, thermal deprotection of the BOC Group, and packing structure of the N‐phenylethynyl polymer
Authors: Yamamoto Takakazu , Yoshizawa Masataka , Mahmut Abla , Abe Masahiro , Kuroda Shin‐ichi , Imase Tatsuya , Sasaki Shintaro 
Published: October 2005

AbstractNew π–conjugated polypyrroles such as poly(3‐heptyl‐N‐(t‐butoxycarbonyl)pyrrole‐2,5‐diyl), PPr(3‐Hep; N‐BOC), and poly(N‐(phenylethynyl)pyrrole‐2,5‐diyl‐alt‐thiophene‐2,5‐diyl), Copoly‐2, were prepared by organometallic polycondensations using the corresponding 2.5‐dihalopyrroles as the starting materials. Deprotection of the BOC group of PPr(3‐Hep; N‐BOC) proceeded at 185 °C to give poly(3‐heptylpyrrole). XRD (X‐ray diffraction) data of Copoly‐2 indicated that Copoly‐2 assumed a stacked structure in the solid. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6223–6232, 2005
Synthesis of cyclic methacrylic acid oligomers by atom transfer radical polymerization
Authors: Saito Reiko , Yamaguchi Kazutaka 
Published: October 2005

AbstractPoly(methacrylic acid) (PMAA) oligomers were synthesized by combining template polymerization and copper‐mediated atom transfer polymerization with multivinyl monomer of β‐cyclodextrin (CD) having 20.4 methacryloyl groups on both primary and secondary hydroxyl group sides of CD scaffold, with 1,3‐dibromobutane as an initiator. The initiation and propagation sites of polymerized sequence of β‐CD were connected by postpolymerization of polymerized products with CuBr and tris[(2‐dimethylamino)ethyl]amine (Me6TREN) in a methanol/water mixture of 10 wt % of water. Polymerized and cyclized sequences, PMAA oligomers formed on the primary and the secondary hydroxyl group sides, were detached from β‐CD scaffold by hydrolysis. Molecular weights of PMAA oligomers were measured by GPC and matrix assisted laser desorption ionization time‐of‐flight mass measurement. By 1H NMR measurements, it was found that three types of cyclic PMAA were obtained by postpolymerization. The cyclization preferentially occurred on the secondary hydroxyl group side than on the primary hydroxyl group side. From the structures of cyclic PMAA, two reaction positions were proposed. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6262–6271, 2005
Highly selective oxidative cross‐coupling polymerization with copper(I)‐bisoxazoline catalysts
Authors: Temma Tomohisa , Habaue Shigeki 
Published: October 2005

AbstractThe asymmetric oxidative coupling polymerization of methyl 6,6′‐dihydroxy‐2,2′‐binaphthalene‐7‐carboxylate with the copper‐diamine catalysts under an O2 atmosphere was carried out. As is the case with the CuCl‐2,2′‐(S)‐isopropylidenbis(4‐phenyl‐2‐oxazoline) [(S)IPhO] catalyst, a polymer with a high cross‐coupling selectivity of 96% was obtained in 71% yield, whose THF‐soluble part had a number‐average molecular weight of 4.5 × 103. To estimate the enantioselectivity with respect to the cross‐coupling linkage in the obtained polymer, the model asymmetric oxidative cross‐coupling reaction with CuCl‐(S)IPhO was also conducted, and the products showed a 94% cross‐coupling selectivity and enantioselectivity of 31% ee (S). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6287–6294, 2005
Glycogen phosphorylase inhibitors: A free energy perturbation analysis of glucopyranose spirohydantoin analogues
Authors: Archontis G. , Watson K. A. , Xie Q. , Andreou G. , Chrysina E. D. , Zographos S. E. , Oikonomakos N. G. , Karplus M. 
Published: October 2005

AbstractGP catalyzes the phosphorylation of glycogen to Glc‐1‐P. Because of its fundamental role in the metabolism of glycogen, GP has been the target for a systematic structure‐assisted design of inhibitory compounds, which could be of value in the therapeutic treatment of type 2 diabetes mellitus. The most potent catalytic‐site inhibitor of GP identified to date is spirohydantoin of glucopyranose (hydan). In this work, we employ MD free energy simulations to calculate the relative binding affinities for GP of hydan and two spirohydantoin analogues, methyl‐hydan and n‐hydan, in which a hydrogen atom is replaced by a methyl‐ or amino group, respectively. The results are compared with the experimental relative affinities of these ligands, estimated by kinetic measurements of the ligand inhibition constants. The calculated binding affinity for methyl‐hydan (relative to hydan) is 3.75 ± 1.4 kcal/mol, in excellent agreement with the experimental value (3.6 ± 0.2 kcal/mol). For n‐hydan, the calculated value is 1.0 ± 1.1 kcal/mol, somewhat smaller than the experimental result (2.3 ± 0.1 kcal/mol). A free energy decomposition analysis shows that hydan makes optimum interactions with protein residues and specific water molecules in the catalytic site. In the other two ligands, structural perturbations of the active site by the additional methyl‐ or amino group reduce the corresponding binding affinities. The computed binding free energies are sensitive to the preference of a specific water molecule for two well‐defined positions in the catalytic site. The behavior of this water is analyzed in detail, and the free energy profile for the translocation of the water between the two positions is evaluated. The results provide insights into the role of water molecules in modulating ligand binding affinities. A comparison of the interactions between a set of ligands and their surrounding groups in X‐ray structures is often used in the interpretation of binding free energy differences and in guiding the design of new ligands. For the systems in this work, such an approach fails to estimate the order of relative binding strengths, in contrast to the rigorous free energy treatment. Proteins 2005. © 2005 Wiley‐Liss, Inc.