bluuebunny/crossref_metadata_2025_split huggingface dataset:
THE DRESDEN 100 T/10 ms PROJECT: A HIGH MAGNETIC FIELD FACILITY AT AN IR-FEL
Authors: DÖRR M. , ECKERT D. , ESCHRIG H. , FISCHER F. , FULDE P. , GROESSINGER R. , GRÜNBERGER W. , HANDSTEIN A. , HINZ D. , KRATZ R. , KRUG H. , LOEWENHAUPT M. , MÜLLER K.-H. , POBELI F. , SCHULTZ L. , SIEGEL H. , STEGLICH F. , VERGES P. 
Published: October 2002

We have proposed to build a 100 T/10 ms, 70 T/100 ms, 60 T/1 s pulsed field user facility with a 50 MJ capacitor bank at the Forschungszentrum Rossendorf near Dresden. This would provide the appealing possibility to have access to Zeeman energies in the energy range of the infrared free-electron-lasers (5 μm to 150 μm; 2 ps; cw; > 10 W) now under construction at the radiation source ELBE (superconducting electron linear accelerator; 40 MeV; 1 mA; 2 ps; cw) in Rossendorf. The work is accompanied by computer simulations of the planned coil systems, of the power supply, and by the development of high-strength conductors aiming at a tensile strength of about 1.5 GPa at σ ≈ σ Cu/2 (microcomposite CuAg alloys and Cu-steel macro compounds). With a view of gaining experience in the construction and operation of pulsed magnets, a pilot pulsed field laboratory was established at the Institute of Solid State and Materials Research Dresden (IFW Dresden). The laboratory includes short pulse magnets with peak field up to 60 T in a 24 mm bore and a rise time of about 10 ms (coil from NHMFL, Tallahassee), and a 40 T long pulse magnet with 24 mm bore and rise time of about 80 ms (coil from METIS, Leuven). The repetition rate of 20 min between pulses is limited by the cooling time of the coils. The coils are energized by a 1 MJ, 10 kV capacitor bank with some special features. With this set-up measurements of magnetization and magnetotransport on 4f-electron systems, for example RECu2, have been out in the temperature range of 1.5 to 300 K and at fields up to 52 T using high precision pick-up coils.
DISCRETE TIME DYNAMIC GAMES WITH A CONTINUUM OF PLAYERS I: DECOMPOSABLE GAMES
Authors: WISZNIEWSKA-MATYSZKIEL AGNIESZKA 
Published: October 2002

The purpose of this paper is to present some simple properties and applications of dynamic games with discrete time and a continuum of players. For such games relations between dynamic equilibria and families of static equilibria in the corresponding static games, as well as between dynamic and static best response sets are examined and an equivalence theorem is proven. The existence of a dynamic equilibrium is also proven. These results are counterintuitive since they differ from results that can be obtained in similar games with a finite number of players. The theoretical results are illustrated with examples describing voting and exploitation of ecological systems.
Packing of ruthenium sensitizer molecules on mostly exposed faces of nanocrystalline TiO2: crystal structure of (NBu4+)2[Ru(H2tctterpy)(NCS)3]2−·0.5 DMSO
Authors: Shklover V. , Nazeeruddin Md. K. , Grätzel M. , Ovchinnikov Yu. E. 
Published: October 2002

AbstractAn X‐ray crystal study of the new ‘black dye’ sensitizer tri(thiocyanato)(4,4′,4″‐tricarboxy‐2,2′:6′,2″‐terpyridine)ruthenium(II) is reported. In the crystal, strong hydrogen bonds form chains of ruthenium complex dianions with the O···O distances of 2.48–2.54 Å. From the molecular geometry of the dianions, structural models of their close packing on the (101) and (001) crystal surfaces of TiO2 (anatase) have been built. The maximum possible density of molecular packing noticeably exceeds the experimental value. The hydrogen bonding between the anions in monolayers, located on the TiO2 surface, is discussed. Copyright © 2002 John Wiley & Sons, Ltd.
Kinetics of esterification of cycloaliphatic epoxies with methacrylic acid
Authors: Srivastava Akanksha , Agrawal Sudha , Rai J. S. P. 
Published: October 2002

AbstractThe esterification of cycloaliphatic epoxy resins CER I and CER II containing glycidyl and cyclohexane epoxy groups, respectively, as their reactive units was carried out using a 1 : 0.9 stoichiometric ratio of resin and methacrylic acid in the presence of triphenylphosphine. The reaction was performed at 80, 85, 90, 95, and 100°C and it followed second‐order kinetics. The specific rate constants, calculated by regression analysis, were found to obey an Arrhenius expression. Kinetic and thermodynamic parameters, activation energy, frequency factor, entropy, enthalpy, and free energy of the reaction, revealed that the reaction was spontaneous and irreversible and produced a highly ordered activated complex. The reactivity of CER II was found to be higher than that of CER I. The difference in the reactivity of the cycloaliphatic epoxies was explained by proposing a reaction mechanism. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3197–3204, 2002
Synthesis and characterization of photosensitive copolymers of 4‐(4′‐nitrocinnamoyl)phenyl acrylate and glycidyl methacrylate
Authors: Subramanian K. , Reddy A. V. R. 
Published: October 2002

AbstractCopolymers of 4‐(4′‐nitrocinnamoyl)phenyl acrylate (NCPA) and glycidyl methacrylate (GMA) were prepared in a methyl ethyl ketone solution with benzoyl peroxide as the initiator at 70°C. They were characterized with UV, IR, 1H‐NMR, 13C‐NMR, and gel permeation chromatography. Copolymer compositions were determined from 1H‐NMR spectra. The monomer reactivity ratios, determined by the method of Kelen and Túdös, were r1 (NCPA) = 1.22 and r2 (GMA) = 0.76. The initial decomposition temperatures of the copolymers were greater than 272°C, as observed by thermogravimetric analysis in air. The photocrosslinking properties of the polymer films were examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3264–3270, 2002
Thermal degradation and combustion of polymeric blends
Authors: Lomakin S. M. , Koverzanova E. V. , Usachev S. V. , Shilkina N. G. , Zaikov G. E. 
Published: October 2002

AbstractThe thermal stability of polymer blends was investigated by means of gas chromatography–mass spectroscopy (GC/MS) and thermal analysis. Evaluated changes in thermal stability can be attributed to blending. On the other hand, we were interested in whether blending may provide a method to control thermal stability and combustibility of polymeric materials. A new scheme of thermal degradation for polystyrene‐polydimethylsiloxane (PDMS) blend was suggested. In the case of polystyrene (PS) as a part of the blend, the products of degradation of PS diffuse through the phase boundary, which cause interaction with PDMS polymers. Apparently, PDMS acts as an inert component, slowing down the termination reaction by dilution of macroradicals formed in random scission degradation process of the PS component. On the other hand, it stabilizes the PS by means of interpolymer recombination, which leads to cross products of thermal degradation. Two of the degradation products: 2‐phenyl‐4(1′,3′,3′,5′,5′‐pentamethylcyclotrisiloxane)‐butane and 2‐phenyl‐4(1′,3′,3′,5′,5′,7′,7′‐heptamethylcyclotrisiloxane)‐butane were assigned to the products of cross‐interpolymer recombination which can accelerate the process of PDMS depolymerization by means of radical initiation of PS* fragments. The connection between a polymer thermal oxidative degradation and its combustion under diffusion flames condition was shown by using composition of polypropylene‐polypropylene‐co‐polyethylene (PP/PP‐co‐PE). In general, the solid‐phase polymer reaction can play a very important role in the reduction of polymer combustibility. It was shown that the composition of PP/PP‐co‐PE (62 : 38) has the highest induction period of autooxidation, which correlates with its combustibility. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3300–3311, 2002
Development of low‐viscosity benzoxazine resins and their polymers
Authors: Wang Yong‐Xia , Ishida Hatsuo 
Published: October 2002

AbstractWith unsubstituted phenol, formaldehyde, and primary aromatic amines as the starting materials, a series of monofunctional benzoxazine resins with low viscosities at room temperature were developed. The polymerization behavior of these resins into thermosetting materials was monitored by differential scanning calorimetry. Stress relaxation of the obtained polybenzoxazines revealed these polymers to be chemically crosslinked networks. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2953–2966, 2002
Novel copolymers for electroluminescent devices
Authors: Wang Haiqiao , Li Xiaoyu 
Published: October 2002

AbstractTwo novel luminescent block copolymers (CE–PPV and CE–DMPPV), containing alternating distyrylbenzene [poly(phenylene vinylene) model oligomer] as light‐emitting units and crown‐ether segments as ionic conductive and spacer units were synthesized by use of a Wittig reaction between the dialdehyde monomer and 1,4‐xylylene‐bis(triphenylphosphonium bromide) or 1,4‐bis(triphenylphosphoniomethyl)‐2,5‐dimethoxybenzene dichloride. The synthesized polymers were characterized with FTIR, 1H‐NMR, UV–Vis, differential scanning calorimetry, and gel permeation chromatography. The number‐average molecular weights were 6896 with a polydispersity index of 1.75 for CE–PPV, and 9301 with a polydispersity index of 2.474 for CE–DMPPV, respectively. The decomposition temperatures and the glass‐transition temperatures were in the range of 395–411°C and 75–77°C, respectively. The electrochemical properties of the copolymers were evaluated and the highest occupied molecular orbital and the lowest unoccupied molecular orbit energy levels of the copolymers were estimated by cyclic voltammetry. Efficient light‐emitting diodes were successfully fabricated. The synthesis, characterization, and electroluminescent properties of the polymers are reported in this study. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3316–3321, 2002
The ring‐opening polymerization of D,L‐lactide catalyzed by new complexes of Cu, Zn, Co, and Ni Schiff base derived from salicylidene and L‐aspartic acid
Authors: Sun Junquan , Shi Weiliang , Chen Deyu , Liang Chengfeng 
Published: October 2002

AbstractD,L‐lactide (LA) was first successfully ring‐opening polymerized in melt by Schiff base complexes K[ML]nH2O [M = Cu(II), Zn(II), Co(II), Ni(II); n = 2, 2, 3, 3.5; H3L = L‐aspartic acid‐salicylidene Schiff base], which were prepared by Schiff base ligand derived from salicylidene and L‐aspartic acid and corresponding acetates. The effects of various complexes, the molar ratio of K[ML]nH2O/LA, the polymerization temperature, and time were studied in detail. The results show that all complexes studied have the ability to initiate the ring‐opening polymerization of D,L‐lactide in melt. More than 90% high polymerization conversion and narrow molecular weight distribution (MWD) can be obtained very easily. However, the Ni(II) complex shows better catalytic property than other complexes on the polymerization and the molecular weight (MW) of poly(D,L‐lactide) (PLA) produced. With a rise in temperature and a prolongation of time, the MW of PLA decreased remarkably. The MW of PLA prepared by all complexes is not very high, which might be related to the crystalline water of complexes. X‐ray study indicated that PLA produced by Ni(II) complex is an amorphous polymer. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3312–3315, 2002
Surface grafting of polyester fiber with chitosan and the antibacterial activity of pathogenic bacteria
Authors: Hu S.‐G. , Jou C.‐H. , Yang M.‐C. 
Published: October 2002

AbstractThree polyesters—poly(ethylene terephthalate), poly(2‐methyl‐1,3‐propylene terephthalate‐co‐ethylene terephthalate), and poly(1,4‐cyclohexylene terephthalate‐co‐ethylene terephthalate)—were preirradiated with 60Co‐γ‐rays. Then, acrylic acid and N‐vinylformamide were grafted to these irradiated fibers. Fibers grafted with N‐vinylformamide were further hydrolyzed with acid so that the amide groups would convert into amino groups, and they were treated with glutaraldehyde so that aldehyde groups would be introduced. Chitosan or chitooligosaccharide was then grafted to these fibers via either esterification or imine formation. Four pathogenic bacteria—methicillin‐resistant Staphylococcus aureus‐1 (MRSA), Staphylococcus aureus‐2, Escherichid coli, and Pseudomonas aeruginosa—were tested to determine the antibacterial activities of chitosan‐grafted and chitooligosaccharide‐grafted fibers. The results showed that grafting chitosan via imine formation could achieve a higher surface density for amino groups and give higher antibacterial activity to those four bacteria tested. The antibacterial activity for E. coli was the highest and that for MRSA was the lowest among the four bacteria tested. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2977–2983, 2002
Fluorescence method using labeled chromophores to study the curing kinetics of a polyurethane system
Authors: González‐Benito J. , Mikeš F. , Baselga J. , Lemetyinemm H. 
Published: October 2002

AbstractA fluorescence method using labeled chromophores to study the curing kinetics of a polyurethane (PU) system was developed. A PU system based on fluorescent‐labeled hexamethylene diisocyanate and a polyol (polyether/polyester) was cured at different temperatures (25, 40, 50, and 65°C). The fluorescent response from the 5‐dimethylaminonaphtalene‐1‐(N‐2‐aminoethyl)sulfonamide and 4‐methacryloylamino‐4′‐nitrostilbene moieties chemically bonded to the PU system was monitored as a function of the curing time. With the fluorescence data, it was possible to model the kinetics of the curing process. Methods based on the fluorescence intensity ratio and the first moment of the fluorescent band emission were applied to determine the degree of curing of the PU system. In addition, it was possible to calculate an apparent activation energy for the curing process, and a value of 17 kJ/mol was obtained. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2992–3000, 2002
Thermally induced microstructural changes in cotton fibers: A free‐volume study
Authors: Ranganathaiah C. 
Published: October 2002

AbstractI measured positron lifetime in natural polymer–cotton fibers as a function of isochronal annealing temperature in the range 27–290°C. The variations in the positron results indicated structural changes occurring in the cotton fibers and determined the glass‐transition temperature as 80°C. Activation energies were measured separately for the crystalline and amorphous regions, indicating the versatility of the technique. These values were close to the OH bond dissociation energy, suggesting OH bond dissociation, the most probable process occurring under thermal treatment. As an extension of the positron results, the molecular weight of the cotton fibers was determined to be 1,200,000 based on free volume, which was within the range suggested for cotton. There seemed to be an indication that crosslinking changed the spiral structure of cotton fibers to the network type. However, this needs to be validated by other measurements. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3336–3345, 2002
Melt versus solvent coating: Structure and properties of block–copolymer‐based pressure‐sensitive adhesives
Authors: O'Connor A. E. , Macosko C. W. 
Published: October 2002

AbstractPressure‐sensitive adhesives (PSAs) composed of a styrene–isoprene–styrene triblock copolymer and a midblock‐associating resin were prepared via solvent and hot‐melt coating. The formulations and thermal histories up to the point of coating were identical, yet significant differences in the properties were observed as a function of the coating method. The solvent‐coated PSA showed superior shear holding power, and the hot‐melt‐coated PSA performed better in tack and peel tests. Two factors resulting from the processing conditions were responsible for these property differences. The quick cooling process occurring after hot‐melt coating led to a poorly defined microstructure and, therefore, less physical crosslinking. Rheological data for melt‐pressed and solvent‐cast PSA films confirmed these microstructural differences. The increased solubility of the tackifier in the solvent additionally created a composition gradient in the solvent coating. Annealing improved the long‐range order of both hot‐melt and solvent coatings, producing a body‐centered cubic microstructure identified by small‐angle X‐ray scattering. This microstructure improved the shear strength of both types of adhesive coatings, whereas the peel and tack properties of the solvent coatings remained inferior to those of the hot‐melt coatings because of differences in the surface compositions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3355–3367, 2002
Simulations on structure performance of 3C thin‐wall injection‐molded parts
Authors: Chen Shia‐Chung , Wang Hsing‐Ling , Chen Juan‐Po , Peng Hsin‐Shu 
Published: October 2002

AbstractManufacturing of 3C (Computer, Communication, and Consumer Electronics) products toward weight reduction, thin‐wall, and minified‐size is an inescapable trend for the future 3C industries. However, the induced damage information from drop impact, including exterior housing fracture, liquid crystal display (LCD) cracking, solder‐joint breaking, or interior component failure, is still derived experimentally and involves very complicated parametric analyses, such as a dynamic impact process, drop orientation, contact behavior, and large deformation during the impact instance. In the present study, numerical simulations for the drop test and bending strength were applied to a thin‐wall computer dictionary (Model CD‐66) housing to understand the key factors that affect the part drop test performance. The appropriate modeling that would affect simulation accuracy as well as the associated nodal degree of freedom and computer time were also investigated. A housing of CD‐66 was redesigned to be 1 mm thick and structurally verified with two different plastics: polycarbonate (PC) and acrylonitrile butadiene styrene (ABS). The simplification of the PC board and LCD backlight circuit in finite element modeling (FEM) only causes about a 10% difference, while saving many modeling costs. The numerical simulations also indicate that both its bending strength and drop‐impact strength were decreased only about 5%, whereas the product quality still met its strength requirement if only the top housing plate thickness was reduced while the remaining sidewall thickness was kept unchanged. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3064–3071, 2002
Initiation and development of the heat‐affected zone in the vibration welding of polyvinylidene fluoride and its copolymers
Authors: Valladares D. , Cakmak M. 
Published: October 2002

AbstractUsing a servo hydraulically controlled vibration‐welding machine, the temporal and spatial development of hierarchical structure in the heat‐affected zone of Poly(vinylidene fluoride) homopolymer and a copolymer of vinylidene fluoride and hexafluorpropylene are investigated. The dynamical changes early in the welding process are rather complex, and start at highly localized regions that then develop rapid adhesive character. In subsequent stages, these regions coalesce and a wave pattern establishes with wave normals oriented in the vibration direction. The crests of the waves near the side surfaces then begin to extrude fibrillar structure. These fibers are also collected and extruded in the vibration direction with their long axes normal to the vibration direction. The production of such features is partly attributed to the high melt elasticity of these polymers that results in instability resulting in their production. X‐ray analysis indicates that the fibers are unoriented in their crystalline regions but electron microscopy studies show that a spiral orientation develops in the extruded fibers indicating that they underwent extension plus twisting deformation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3377–3388, 2002
Acidic and basic hydrolysis of poly(N‐vinylformamide)
Authors: Gu L. , Zhu S. , Hrymak A. N. 
Published: October 2002

AbstractPoly(N‐vinylformamide) (PNVF) was synthesized and hydrolyzed to poly(vinylamine) (PVAm) in both HCl and NaOH solutions. The hydrolysis kinetics and the equilibrium hydrolysis were examined experimentally at different temperatures, polymer concentrations, and acid‐ or base‐to‐amide molar ratios. The hydrolysis kinetics strongly depended on temperature, polymer, and HCl or NaOH concentrations, but showed little dependence on PNVF molecular weight. The acid hydrolysis of PNVF exhibited limited conversions because of the electrostatic repulsion among the cationic amine groups generated during hydrolysis and proton hydrates. In the basic hydrolysis, complete amide conversions were observed when the NaOH/amide molar ratios were greater than unity. The effects of temperature and PNVF concentration on the equilibrium amide conversion appeared to be negligible in both acidic and basic hydrolysis. The equilibrium conversions of base hydrolysis were higher than those of acidic hydrolysis under the same reaction conditions. At NaOH/amide ratios of less than unity, the equilibrium hydrolysis experiments revealed that one base molecule could induce the hydrolysis of more than one amide group. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3412–3419, 2002
Retention of gallium ions from acidic solutions by pyridine strong‐base anion exchangers
Authors: Dulman Viorica , Buhaceanu Rodica , Luca Cornelia , Neagu Violeta 
Published: October 2002

AbstractUsing the batch method, the retention of Ga(III) from HCl solutions by two gel‐type pyridine strong‐base anion exchangers containing 1‐methyl‐ or 1‐butyl‐4‐vinylpyridinium chloride structural units, called S1 and S2 resins, respectively, was studied. The influence of the HCl and Ga(III) concentrations as well as of the contact time between the resin and the liquid phase was investigated. The parameters, which characterize the retention process, were estimated using Langmuir and Freundlich isotherms. Both resins exhibited a higher affinity for gallium ions from a 6M HCl solution. According to Langmuir isotherms, maximum retention capacities of 44.44 and 60 mg Ga(III)/g dry resin for the S1 and S2 resins, respectively, were obtained. Freundlich isotherms provide additional proof for a higher affinity of the S2 resin for Ga(III) from HCl solutions. It is clear that the substituent length increase on N+ atoms led to an increasing affinity of the pyridine strong base anion exchangers toward Ga(III). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3440–3444, 2002
Reactive melt blending of modified polyamide and polypropylene: Assessment of compatibilization by fractionated crystallization and blend morphology
Authors: Pompe Gisela , Pötschke Petra , Pionteck Jürgen 
Published: October 2002

AbstractThe melting and crystallization behavior of nonreactive and reactive melt‐mixed blends of polypropylene and carboxylic‐modified polyamide (mPA) as the dispersed phase was investigated. It was found that the size of the mPA particles decreases and the crystallization behavior of the mPA particles changes in dependence on the mixing time of the blends with oxazoline‐modified PP (mPP). This indicates that an in situ reaction occurs between the oxazoline groups of mPP and the carboxylic acid groups of mPA, resulting in a compatibilizing effect. In blends with mPP, the crystallization of the dispersed mPA phase splits into two steps. Below a critical particle size, the mPA does not crystallize at temperatures typical for bulk crystallization. These finely dispersed mPA particles crystallize coincidently with the PP phase, and this part increases with increasing mixing time. Analysis of the crystallization heat of both steps in connection with the particle volume distribution permits the estimation of the critical particle size to be ≤4 μm. These investigations showed that the effect of fractionated crystallization can be used to follow the morphology development and to evaluate the efficiency of compatibilizing interfacial reactions during processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3445–3453, 2002