bluuebunny/crossref_metadata_2025_split huggingface dataset:
Space–time meshfree collocation method: Methodology and application to initial‐boundary value problems
Authors: Netuzhylov Hennadiy , Zilian Andreas 
Published: May 2009

AbstractA novel space–time meshfree collocation method (STMCM) for solving systems of non‐linear ordinary and partial differential equations by a consistent discretization in both space and time is proposed as an alternative to established mesh‐based methods. The STMCM belongs to the class of truly meshfree methods, i.e. the methods that do not have any underlying mesh, but work on a set of nodes only without any a priori node‐to‐node connectivity. Instead, the neighbouring information is established on‐the‐fly. The STMCM is constructed using the Interpolating Moving Least‐squares technique, which allows a simplified implementation of boundary conditions due to fulfillment of the Kronecker delta property by the kernel functions, which is not the case for the major part of other meshfree methods.The method is validated by several examples ranging from interpolation problems to the solution of PDEs, whereas the STMCM solutions are compared with either analytical or reference ones. Copyright © 2009 John Wiley & Sons, Ltd.
Dynamic‐spatial management of coastal aquifers
Authors: Kan Iddo , Leizarowitz Arie , Tsur Yacov 
Published: May 2009

AbstractWe analyze the management of a coastal aquifer under seawater intrusion (SWI) using distributed control methods. The aquifer's state is taken as the water head elevation (vis‐à‐vis sea level, say), which varies with time and in space since extraction, natural recharge and lateral water flows vary with time and in space. The water head, in turn, induces a temporal‐spatial SWI process, which changes the volume of fresh water in the aquifer. Under reasonable conditions we show that the optimal state converges to a steady‐state process that is constant in time. We characterize the optimal steady‐state process in terms of a standard control problem (in space) and offer a tractable algorithm to solve for it. Copyright © 2009 John Wiley & Sons, Ltd.
Shear induced clay organo‐modification: application to plasticized starch nano‐biocomposites
Authors: Chivrac Frédéric , Pollet Eric , Avérous Luc 
Published: May 2009

AbstractThe present paper reports the successful development of a straightforward clay organo‐modification protocol named “Shear Induced Clay Organo‐modification” process, or SICO. To develop such a fast process, natural montmorillonite has been organo‐modified with cationic starch (surfactant) under shearing. According to the obtained results, this process allows the preparation of a pre‐exfoliated montmorillonite, organo‐modified by cationic starch (OMMT‐CS). Then, the OMMT‐CS has been dispersed into different plasticized starch‐based plastics, varying the polysaccharide botanical source, to obtain nano‐biocomposites displaying an exfoliated morphology. To establish the efficiency of this protocol and highlight this nano‐structuration, uniaxial tensile tests have been performed on these materials. The mechanical properties have been compared with those obtained with nano‐biocomposites elaborated with OMMT‐CS prepared with the conventional and efficient Exfoliation/Adsorption technique. Since comparable properties are obtained, we assume that the SICO process is a powerful technique to easily and quickly organo‐modify the montmorillonite clay and to obtain exfoliated nano‐biocomposites. Copyright © 2009 John Wiley & Sons, Ltd.
Nanofibrous polyaniline thin film prepared by plasma‐induced polymerization technique for detection of NO2 gas
Authors: Tiwari Ashutosh , Kumar Rajendra , Prabaharan Mani , Pandey Ravi R. , Kumari Premlata , Chaturvedi Anurag , Mishra A. K. 
Published: May 2009

AbstractA nanofibrous polyaniline (PANI) thin film was fabricated using plasma‐induced polymerization method and explored its application in the fabrication of NO2 gas sensor. The effects of substrate position, pressure, and the number of plasma pulses on the PANI film growth rate were monitored and an optimum condition for the PANI thin film preparation was established. The resulting PANI film was characterized with UV–visible spectrophotometer, FTIR, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The PANI thin film possessed nanofibers with a diameter ranging from 15 to 20 nm. The NO2 gas sensing behavior was studied by measuring the change in electrical conductivity of PANI film with respect to NO2 gas concentration and exposure time. The optimized sensor exhibited a sensitivity factor of 206 with a response time of 23 sec. The NO2 gas sensor using nanofibrous PANI thin film as sensing probe showed a linear current response to the NO2 gas concentration in the range of 10–100 ppm. Copyright © 2009 John Wiley & Sons, Ltd.
Sustained first remission in an adolescent with hepatosplenic T‐cell lymphoma treated with T‐cell leukemia induction, nucleoside analog‐based consolidation, and early hematopoietic stem cell transplant
Authors: Schafer Eric , Chen Allen , Arceci Robert J. 
Published: May 2009

AbstractHepatosplenic T‐cell lymphoma (HTCL) is a rare malignancy. Prognosis is poor with only a few case reports of long‐term survivors. While HTCL universally involves the bone marrow, the condition has been most often treated with multimodal lymphoma specific chemotherapy. We report a durable, sustained first remission in an adolescent treated for HTCL who received induction therapy according to a high risk T‐cell leukemia regimen, a nucleoside analog‐based consolidation, and allogeneic transplantation associated with GVHD. Pediatr Blood Cancer 2009;53:1127–1129. © 2009 Wiley‐Liss, Inc.
Effects of TEOS contents on swelling behaviors and mechanical properties of thermosensitive hybrid gels
Authors: Huang Wei‐Jen , Lee Wen‐Fu 
Published: May 2009

AbstractA series of organic‐inorganic hybrid thermosensitive gels with three different structures and different contents of tetraethoxysilane (TEOS) were prepared from N‐isopropylacrylamide (NIPAAm), and N,N′‐methylene‐bis‐acrylamide (NMBA) and TEOS [N‐IPN]; NIPAAm, 3‐(trimethoxysilyl) propyl methacrylate (TMSPMA) as coupling agent and TEOS [NT‐IPN]; and NIPAAm, TMSPMA and TEOS [NT‐semi‐IPN] by emulsion polymerization and sol‐gel reaction in this study. The effect of TEOS content on the swelling behavior, mechanical properties, and morphologies of the present gels was investigated. Results showed that the properties of the gels would be affected by the gel networks such as IPN or semi‐IPN, existence of TMSPMA as the bridge chain between networks, and content of TEOS. The NT‐semi‐IPN gel had higher swelling ratio because poly (NIPAAm) moiety in the semi‐IPN gels was not restricted by NMBA network. However, the IPN gels such as N‐IPN and NT‐IPN had good mechanical properties and lower swelling ratio, but had bad thermosensitivity due to the addition of coupling agent, TMSPMA, into the gel system that resulted in denser link between organic and inorganic components. Increasing TEOS content would also reduce the thermosensitivity of the hybrid gels. The morphology showed that IPN gels had partial aggregation (siloxane domain) and showed some denser phases. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
The turning point on plots of log ϕ and log t of Mo's equation
Authors: Song Jian‐bin , Mo Zhi‐shen , Lu Chun‐hua , Ren Min‐qiao , Zhang Qiu‐ping , Liu Yu‐jian , Ni Ya‐ru , Xu Zhong‐zi 
Published: May 2009

AbstractBACKGROUND: Mo's equation based on the Avrami equation and Ozawa equation has been successfully used in non‐isothermal crystallization kinetics by many researchers. However, in recent years we have found that plots of log ϕ–log t of Mo's equation are not straight lines, but there appears a turning point at ϕ = 7 °C min−1 or so. The aim of this article is to analyze in detail the reason for the occurrence of this turning point by studying the non‐isothermal crystallization of poly(vinylidene fluoride) (PVDF) using differential scanning calorimetry.RESULTS: A turning point at about 7 °C min−1 appeared on plots of log ϕ–log t. The cooling rate where the turning point occurred showed little change with increasing relative crystallinity, but the temperature decreased. It is noted that this turning‐point temperature is lower than transition temperature of regime I → II reported for PVDF.CONCLUSION: We deemed that the occurrence of turning points on plots of log ϕ–log t of Mo's equation can be ascribed to the different crystallization regimes based on the Hoffman nucleation theory, and presumed that the turning point corresponded to transition of regime I → II. Finally, we considered that Mo's equation should be analyzed using two beelines, instead of one beeline. Copyright © 2009 Society of Chemical Industry
Synthesis and optoelectronic properties of liquid‐crystalline copolymers based on fluorene and triphenylamine‐containing oligo(p‐phenylenevinylene) derivatives for white light emission
Authors: Li Hui , Wang Lei , Zhao Bin , Shen Ping , Tan Songting 
Published: May 2009

AbstractA series of novel liquid‐crystalline copolymers based on fluorene and triphenylamine‐containing oligo(p‐phenylenevinylene) derivatives have been synthesized according to the Suzuki polymerization method. The structures, optical and electrochemical properties of the copolymers were characterized by 1H NMR, 13C NMR, GPC, UV–vis, photoluminescence (PL) spectroscopy, and cyclic voltammetry (CV), respectively. The thermotropic phase behavior of the copolymers was investigated by using differential scanning calorimetry (DSC) and polarized optical microscope (POM). All of the copolymers exhibit thermally liquid crystalline properties and represent the characteristic Schlieren textures in a wide temperature range. The effects of the concentrations and chain length of the oligo(phenylenevinylene) units on the thermal properties, liquid crystalline, photo‐ and electroluminescent properties of the copolymers have been investigated in details. Among the copolymers‐based devices with a configuration of ITO/PEDOT:PSS/polymers/Ca/Al, the device based on PF‐LOPV05 exhibits the lowest turn‐on voltage of 3 V and the maximum brightness of 210 cd/m2 at 8.3 V. A single layer device based on the blend of PF/PF‐LOPV05 emits white electroluminescence with CIE coordinates of (0.30, 0.35) at 8 V. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3296–3308, 2009
Locally sulfonated poly(ether sulfone)s with highly sulfonated units as proton exchange membrane
Authors: Matsumoto Kazuya , Higashihara Tomoya , Ueda Mitsuru 
Published: May 2009

AbstractNovel locally sulfonated poly(ether sulfone)s with highly sulfonated units were successfully synthesized for fuel cell applications. Poly(ether sulfone)s were prepared by the nucleophilic substitution of bis(4‐fluorophenyl) sulfone with 1,2,4,5‐tetrakis([1,1′‐biphenyl]‐2‐oxy)‐3,6‐bis(4‐hydroxyphenoxy)benzene and bis(4‐hydroxyphenyl) sulfide, followed by oxidation using m‐chloroperoxybenzoic acid. The desired highly sulfonated units were easily introduced by postsulfonation and each one had ten sulfonic acid groups. The sulfonated polymers gave tough, flexible, and transparent membranes by solvent casting. The high contrast in polarity between highly sulfonated units and hydrophobic poly(ether sulfone) units enabled the formation of defined phase‐separated structures and well‐connected proton paths. The sulfonated polymers exhibited excellent proton conductivity over a wide range of relative humidities. The proton conductivity of the sulfonated polymer with an ion exchange capacity value of 2.38 mequiv/g was comparable to that of Nafion 117 even at 30% relative humidity. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3444–3453, 2009
Direct patterning of poly(amic acid) and low‐temperature imidization using a crosslinker, a photoacid generator, and a thermobase generator
Authors: Ogura Tomohito , Higashihara Tomoya , Ueda Mitsuru 
Published: May 2009

AbstractA positive‐type photosensitive polyimide (PSPI) based on poly(amic acid) (PAA), a crosslinker 1,1,1‐tris{4‐[2‐(vinyloxy)ethoxy]phenyl}ethane (TVPE), a photoacid generator (PAG) (5‐propylsulfonyloxyimino‐5H‐thiophen‐2‐ylidene)‐2‐(methylphenyl)acetonitrile (PTMA), and a thermobase generator (TBG) t‐butyl 2,6‐dimethylpiperidine‐1‐carboxylate (BDPC) has been developed as a promising material in microelectronics. The PAA was prepared from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (BPDA) and 4,4′‐oxydianiline (ODA) in dimethyl sulfoxide (DMSO). The PSPI, consisting of PAA (69 wt %), TPVE (21 wt %), PTMA (3 wt %), and BDPC (7 wt %), showed high sensitivity of 21 mJ/cm2 and a high contrast of 6.8 when it was exposed to a 436‐nm line (g‐line), postbaked at 90 °C for 5 min, and developed with 1.69 wt % TMAHaq. A clear positive image of 8 μm line and space pattern was printed on film, which was exposed to 50 mJ/cm2 of g‐line by a contact printing mode and fully converted to the corresponding polyimide (PI) pattern on heating at 200 °C, confirmed by FTIR spectroscopy. Thus, this system will be a good candidate for next generation PSPIs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3362–3369, 2009
Frontal polymerization synthesis and characterization of Konjac glucomannan‐graft‐acrylic acid polymers
Authors: Li Jing , Zhang Xia , Chen Jian , Xia Jun , Ma Meihu , Li Bin 
Published: May 2009

AbstractKonjac glucomannan‐graft‐acrylic acid polymers, used as superabsorbent polymers (SAPs), were synthesized by frontal polymerization (FP). The features of front propagation including front velocity and maximum temperature (Tmax) were influenced by the amount of glucomannan, initiator, and environment temperature. The graft copolymer was characterized by FTIR, DSC, and SEM. The amount of crosslinking agent mainly determined the crosslinking degree of SAPs that would affect the water absorbency and microstructure. Water absorbency of SAP was also investigated and most of them displayed high water absorption rate. The aforementioned results allow us to conclude that FP can be considered as a promising method to fabricate SAP for its excellent advantages. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3391–3398, 2009
Low band gap copolymers based on thiophene and quinoxaline: Their electronic energy levels and photovoltaic application
Authors: Peng Qiang , Xu Jun , Zheng Wenxu 
Published: May 2009

AbstractLow band gap conjugated copolymers containing donor (thiophene)‐acceptor (quinoxaline, Qx) were synthesized via Stille coupling polymerization. The resulting copolymers were characterized by 1H NMR, element analysis, GPC, TGA, and DSC. UV‐vis spectra indicated that the increase in the content of quinoxaline units increased the interaction strengthen of the polymer main chains and caused a red‐shift in the optical absorbance. Cyclic voltammetry was used to estimate energy levels of the lowest unoccupied molecular orbit (LUMO) and the highest occupied molecular orbit (HOMO), and the band gap (Eg) of the copolymers. The basic electronic structures of the copolymers were also studied by density‐functional theory (DFT) calculations. Both the experimental and calculation results indicated an increase in the HOMO energy level with increasing the content of quinoxaline units, whereas the corresponding change in the LUMO energy level is much smaller. Polymer photovoltaic cells (PVCs) were fabricated with the structure of ITO/PEDOT:PSS (30 nm)/active layer (80 nm)/Ca (8 nm)/Al(140 nm). The results show that the introduction of a proper amount of electron‐acceptor groups in the polymer main chains induces an extension of the absorption spectra and improves the photovoltaic properties of the copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3399–3408, 2009
Photochemistry and initiation behavior of phenylethynyl onium salts as cationic photoinitiators
Authors: Höfer Michael , Liska Robert 
Published: May 2009

AbstractPhenyl(phenylethynyl)iodonium hexafluorophosphate and diphenyl(phenylethynyl)sulfonium hexafluorophosphate were synthesized for application as cationic photoinitiators using simple, straightforward methods. Quantification of the purity of the counterion was determined by FTIR analysis with subsequent mathematical peak deconvolution. Photodecomposition products for direct irradiation were determined in steady state photolysis experiments yielding diphenyl sulfide and phenyl(phenylethynyl) sulfide or iodobenzene, respectively, as main products. Heterolytic cleavage was proposed as main photodecomposition pathway because low yields of phenylacetylene radical recombination products and no photoproducts generated by phenyl radicals, including benzene, were detected. High activity as photoinitiators was verified by photo‐DSC experiments in direct irradiation and in photosensitized initiation using 9,10‐dibutylanthracene, 2‐isopropylthioxanthone, and surprisingly also benzophenone as sensitizers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3419–3430, 2009
Synthesis of stimuli‐responsive macroazoinitiators and their use as an inistab toward hairy polymer latex particles
Authors: Fujii Syuji , Kakigi Yuichi , Suzaki Motomichi , Yusa Shin‐Ichi , Muraoka Masahiro , Nakamura Yoshinobu 
Published: May 2009

AbstractStimuli‐responsive macroazoinitiators with central azo unit have been synthesized by atom transfer radical polymerization (ATRP) of 2‐(dimethylamino)ethyl methacrylate or 2‐(diethylamino)ethyl methacrylate in 2‐propanol at 25 °C. The mean degree of polymerization of the polymer chains besides the azo group was fixed between 25 and 60. 1H NMR, gel permeation chromatography, UV‐Vis spectrophotometer, and surface tensiometer were used to characterize the stimuli‐responsive macroazoinitiators in terms of their chemical structure, molecular weight, polydispersity, and pH‐responsive behavior, respectively. Eventually, dispersion polymerization of styrene using the poly[2‐(diethylamino)ethyl methacrylate] (PDEA) macroazoinitiator as an inistab (initiator + stabilizer) in 2‐propanol medium was conducted. Near‐monodisperse 98 nm polystyrene (PS) latex particles with pH‐responsive PDEA hair were successfully synthesized. The PS latex particles with the PDEA hair can be dispersed in acidic aqueous media where the PDEA hair was protonated and was solvated, and can be flocculated in basic aqueous media where the PDEA hair was deprotonated and was precipitated. This dispersion‐flocculation cycle was reversible. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3431–3443, 2009
Intermolecular interactions on amine‐cured epoxy matrices with different crosslink densities. Influence on the hole and specific volumes and the mechanical behavior
Authors: Blanco M. , Ramos J. A. , Goyanes S. , Rubiolo G. , Salgueiro W. , Somoza A. , Mondragon I. 
Published: May 2009

AbstractThe architecture of an epoxy matrix was modified by curing the resin with mono‐/diamine mixtures having identical chemical structures. Both hole volume and specific volume variations were studied by positron annihilation lifetime spectroscopy and pressure‐volume‐temperature/density measurements, respectively. The average hole volume of the networks at room temperature slightly increased when the monoaminic chain extender content increased. The increment in the intermolecular interactions between functional groups of the networks chains, due to the less hindered nitrogen introduced by the monoamine, appears to be the responsible for the observed behavior. Besides, only small variations on the specific volume were observed on increasing the monoamine content, which points out that for a cured epoxy system, the chemical structure of the curing agent is mainly responsible for chain packing in the networks. On the other hand, intermolecular interactions between chains were considered as the key factor for fixing stiffness and strength. Thus, it was observed that the increase of the intermolecular interactions with the monoamine content produced a decrease in the sub‐Tg small‐range cooperative motions, which increased the low‐deformation mechanical properties at temperatures between β and α relaxations. This conclusion could be applied to previous investigations with epoxy matrices not fully crosslinked (nonstoichiometric or noncompletely cured formulations). Finally, it was found that fracture properties do not significantly depend either on the hole volume or on the intermolecular interactions. Fracture properties are more dependent on the crosslink density and the glass transition temperature. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1240–1252, 2009
Proton conductivity survey of the acid doped copolymers based on 4‐vinylbenzylboronic acid and 4(5)‐vinylimidazole
Authors: Sezgin Aslihan , Akbey Ümit , Graf Robert , Bozkurt Ayhan , Baykal Abdülhadi 
Published: May 2009

AbstractIn this work, poly(4‐vinylbenzylboronic acid‐co‐4(5)‐vinylimidazole) (poly(4‐VBBA‐co‐4‐Vim)) copolymers were synthesized by free‐radical copolymerization of the monomers 4‐VBBA and 4‐Vim at various monomer feed ratios. The copolymers were characterized by 1H MAS NMR and 11B MQ‐MAS NMR methods and the copolymer composition was determined via elemental analysis. The membrane properties of these copolymers were investigated after doping with phosphoric acid at several stoichiometric ratios. The proton exchange reaction between acid and heterocycle is confirmed by FTIR. Thermal properties of the samples were investigated via thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC). The morphology of the copolymers was characterized by x‐ray diffraction, XRD. The temperature dependence of proton conductivities of the samples was investigated by means of impedance spectroscopy. Proton conductivity of the copolymers increased with the doping ratio and reached to 0.0027 S/cm for poly(4‐VBBA‐co‐4‐Vim)/2H3PO4 in the anhydrous state. The boron coordination in the copolymer was determined by 11B MQ‐MAS experiment and the coexistence of three and four coordinated boron sites was observed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1267–1274, 2009
Stress relaxation under large step equibiaxial elongation for low‐density polyethylene
Authors: Okamoto Kenzo , Yamaguchi Masayuki 
Published: May 2009

AbstractThe stress relaxation under large step equibiaxial elongation for low‐density polyethylene with long‐chain branches revealed that the time‐strain separability holds in relaxation modulus GB(t, εB), and damping function hB(εB) exhibits weaker equibiaxial elongational strain εB dependence than that predicted by the Doi–Edwards theory without the independent alignment approximation. Dependencies of damping function h(γ) for step shear deformation and hB(εB) on stretch ratio α of polymer contour length and orientation of a polymer chain in direction of the maximum orientation were evaluated, and it was found that the α dependencies of h(γ) and hB(εB) are different, whereas dependencies of h(γ) and hB(εB) on the orientation coincide fairly well. These results indicate that the damping is dominated by the chain orientation rather than α. This implies that withdrawal of long‐chain branches into tube of a backbone chain occurs when the orientation of the long‐chain branches is large and friction force against the branch point withdrawal is small. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1275–1284, 2009