bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of various added compatibilizers on the crystalline structure of polypropylene homopolymer/polybutylene terephthalate and polypropylene copolymer/polybutylene terephthalate polymer blends
Authors: Vashi P. N. , Kulshreshtha A. K. , Dhake K. P. 
Published: December 2002

AbstractBlends of semicrystalline isotactic polypropylene homopolymer and polypropylene copolymer with polybutylene terephthalate with different compatibilizers [i.e., styrene acrylonitrile, Surlyn, styrene–ethylene–butadiene styrene (SEBS), block copolymer and SEBS block copolymer grafted with maleic anhydride] were prepared by melt blending. Wide angle‐X‐ray scattering patterns of injection moldings were obtained. The crystallinity index and d‐spacing were calculated with different concentrations of different compatibilizers. X‐ray results in the structural investigation of the compatibilized blends correlated well with the different compatibilizer concentrations. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1190–1193, 2003
Viscometric studies of poly(N‐vinyl‐2‐pyrrolidone) in water and in water and 0.01% bovine serum albumin at 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, and 313.15 K
Authors: Singh Man , Kumar Sanjay 
Published: December 2002

AbstractViscosity and density studies for 0.01–0.14% (w/w) poly(N‐vinyl‐2‐pyrrolidone) (PVP) in water and in water and 0.01% bovine serum albumin (BSA) were conducted at 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, and 313.15 K. The viscosity coefficients and the activation‐energy, free‐energy, enthalpy, and entropy changes were calculated from viscosity data for viscous flow. On this basis, PVP–PVP, PVP–BSA, PVP–water, and BSA–water interactions and PVP and BSA shape factors were investigated and rationalized in terms of the water structure. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1001–1015, 2003
Nonisothermal crystallization behavior of poly (butylene terephthalate)–poly (ethylene terephthalate‐co‐isophthalate‐co‐sebacate) segmented copolyesters
Authors: Zhao Yun Hui , Sheng Jing , Wang Ya Quan 
Published: December 2002

AbstractIn this paper, two different analytical methods were applied to investigate nonisothermal crystallization behavior of copolyesters prepared by melting transesterification processing from bulk polyesters involving poly (butylene terephthalate) (PBT) and ternary amorphous random copolyester poly(ethylene terephthalate‐co‐isophthalate‐co‐sebacate) (PETIS). The results show that the half‐time of crystallization of copolyesters depended on the reaction time and decreased with the content of ternary polyesters in the amorphous segment. The modified Avrami model describes the nonisothermal crystallization kinetics very well. The values of the Avrami exponent range from 2.2503 to 3.7632, and the crystallization kinetics constant ranges from 0.0690 to 0.9358, presenting a mechanism of three‐dimensional spherulitic growth with heterogeneous nucleation. Ozawa analysis, however, failed to describe the nonisothermal crystallization behavior of copolyesters, especially at higher cooling rate. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1232–1238, 2003
Synthesis and characterization of poly(N‐isopropylacrylamide)s initiated with siloxane oligomer–(NH4)2Ce(NO3)6 redox pair
Authors: Erbil Candan , Akın Hatice , Uyanık Nurseli 
Published: December 2002

AbstractPoly(N‐isopropylacrylamide)s (PNIPAAM)s were synthesized via free‐radical polymerization using a ceric ammonium nitrate, Ce(IV)–α‐ω‐dihydroxy(polydimethylsiloxane) (Tegomer H‐Si 2111, PDMS) redox pair in hexane at 30°C in a nitrogen atmosphere. The dependence of the initiation and termination steps on the [NIPAAM]/[Ce(IV)] and [NIPAAM]/[PDMS] ratios were studied using gravimetry and FTIR, 1H‐NMR, UV‐vis, and GFAA spectroscopy techniques. Gravimetric results indicated that, in the case of high concentrations of PDMS, the percentage of the solid portions of the products decreased while the amount of the oligomeric NIPAAM chains increased, that is, as the amount of PDMS in hexane was increased, the number of the short NIPAAM chains having PDMS segments at the two ends, also increased. UV‐vis results showed that the LCST of PNIPAAM initiated with Ce(IV) alone was higher than those of the ones that were synthesized using common initiator systems such as an ammonium persulfate–N,N,N′,N′‐tetramethylethylenediamine redox pair and azobis(isobutyronitrile). Further, it was observed that both siloxane blocks and NH groups forming coordination bonds with free Ce(IV) ions and/or metal–ligand complexes had an important effect on the aggregation process of the chains. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1248–1254, 2003
Modification of poly(octadecene‐alt‐maleic anhydride) films by reaction with functional amines
Authors: Schmidt Ute , Zschoche Stefan , Werner Carsten 
Published: December 2002

AbstractThin films of poly(octadecene‐alt‐maleic anhydride) on top of Si wafers and glass plates were modified by reactions with different functional amines to be used in future studies on the relevance of certain molecular surface properties for the covalent immobilization of proteins. For that aim, a strategy was developed and applied to convert the anhydride moieties of the copolymer by functional amines into side chains bearing hydrophilic groups of acidic (carboxylic acid, sulfonic acid), basic (amines), or neutral (poly(ethylene oxide) (PEO), glucose) character. The modification of the copolymer films was achieved through the two‐step formation of a cyclic imide, which was very stable in aqueous solution. Depending on the reactivity of the applied amine, the adjustment of the reaction time was suitable for the preparation of partially converted surfaces of the polymer film. Degrees of modification between 5 and 30% (according to X‐ray photoelectron spectroscopy data) were obtained. Annealing the modified polymer films induced efficient back‐formation of the anhydride groups. By reaction of the layered polyanhydrides with highly crosslinked diamines, amine‐functionalized polymer films were produced that were capable of binding secondary polyanhydride layers. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1255–1266, 2003
Acetylation of wheat straw using simplified procedure and ultrasonic irradiation
Authors: Sun Run‐Cang , Sun X. F. 
Published: December 2002

AbstractAn investigation of the acetylation of wheat straw with acetic anhydride using a simplified procedure and with or without ultrasonic irradiation was undertaken. The new procedure greatly shortened the reaction time and simplified the chemical recovery. Acetylation weight gains of 15.8% can be achieved in 1 h at 120°C without ultrasound assistance. At the same reaction conditions but with ultrasound assistance at 60°C for 5 min, a weight percent gain (WPG) value of 15.0% was obtained, indicating a slightly negative effect of ultrasonic irradiation on the rate of acetylation without solvents or catalysts. However, a positive sonication effect on the solubility of low molecular materials, mainly extractives, was found in all the cases of the reactions. The characterization of acetylated wheat straw was performed by FTIR, solid‐state 13C‐NMR, and thermal studies, which provided evidence for acetylation. The thermal stability of acetylated straw was found to be higher than that of unmodified wheat straw. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1277–1284, 2003
1,6‐hexanediol diacrylate‐crosslinked polystyrene: Preparation, characterization, and application in peptide synthesis
Authors: Arunan C. , Pillai V.N. Rajasekharan 
Published: December 2002

AbstractA copolymer of 1,6‐hexanediol diacrylate (HDODA) and styrene was prepared by a suspension polymerization method. The resin was characterized by infrared and carbon‐13 cross‐polarization magic‐angle spin (13C CP‐MAS) spectroscopy. The topology of the resin was examined by scanning electron microscopy (SEM). The polymer swells extensively in common solvents used for peptide synthesis. The resin exhibited chemical stability even in neat trifluoroacetic acid. The applicability of the new resin was demonstrated by synthesis of Val‐Ala‐Val‐Ala‐Ala‐Gly, Gln‐Val‐Gly‐Gln‐Val‐Glu‐Leu‐Gly, and Val‐Gln‐Ala‐Ala‐Ile‐Asp‐Tyr‐Ile‐Asn‐Gly. Comparative synthetic studies showed that the new resin is superior to divinylbenzene (DVB)‐based resin in the case of the synthesis of hydrophobic peptide sequences. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1290–1296, 2003
Lignocellulosic flour‐reinforced poly(hydroxybutyrate‐co‐valerate) composites
Authors: Dufresne Alain , Dupeyre Danièle , Paillet Michel 
Published: December 2002

AbstractResidual lignocellulosic flour from spruce and ground olive stone was used as a natural filler in poly(hydroxybutyrate‐co‐valerate) (PHBV)‐based composites. The morphology and the thermal properties of these composites were investigated by scanning electron microscopy and differential scanning calorimetry, respectively. Lignocellulosic fillers acted as nucleating sites for the crystallization of PHBV and strongly enhanced its degree of crystallinity. Dynamic mechanical analysis and tensile properties of these materials were also studied. A significant reinforcing effect was displayed by dynamic mechanical analysis at temperatures higher than the glass–rubber transition of the matrix. In addition, for low‐particle‐size spruce, a stabilization of the modulus was observed up to 500 K. High‐strain tensile properties did not show any reinforcing effect. This apparent disagreement was explained by the poor adhesion between the hydrophilic lignocellulosic filler and the hydrophobic polymeric matrix. To validate this hypothesis, the experimental data were compared with predicted data involving the percolation concept. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1302–1315, 2003
Polymer‐supported iminodiacetamides for selective mercury extraction
Authors: Sonmez Hayal Bulbul , Senkal B. Filiz , Bicak Niyazi 
Published: December 2002

AbstractA new polymeric resin with iminodiacetamide functions has been prepared for the selective extraction of mercuric ions. This polystyrene sulfone amide‐based resin with a 9.6 mmol g−1 amide content is able to selectively sorb mercury over many metal ions, including Cd(II), Zn(II), Fe(III), and Pb(II). Among these, Cd(II) and Zn(II) ions are not sorbed at all, and Fe(III) and Pb(II) ions show only trace absorptions (0.58 and 0.17 mmol/g, respectively) under the same conditions. The selectivity of the resin, its high mercury loading capacity (4.23 mmol g−1), and its ability to regenerate via acetic acid make it a promising material for the large‐scale selective separation of mercuric ions from aqueous mixtures. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1316–1321, 2003
The adsorption of Cu(II) ion from aqueous solution upon acrylic acid grafted poly(ethylene terephthalate) fibers
Authors: Karakışla Meral 
Published: December 2002

AbstractThis study is concerned with the investigation of the adsorption properties of acrylic acid grafted poly(ethylene terephthalate) fibers by the use of Cu(II) ions in aqueous solutions. Influence of pH, graft yield, contact time, concentration of the ion, and reaction temperature on the amount of ion adsorbed upon reactive fiber were investigated. The time in which the adsorption reached to the equilibrium value was determined as 1 h. The adsorption isotherm of Cu(II) ion was found to be a Langmuir type and the heat of adsorption was calculated as −10.1 kJ mol−1. It was observed that the adsorbed Cu(II) ion upon acrylic acid grafted poly(ethylene terephthalate) fibers could be recovered in acidic media. The fiber could also readsorb Cu(II) ions without losing its activity. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1216–1220, 2003
Characterization of polymer‐layered silicate (clay) nanocomposites by transmission electron microscopy and X‐ray diffraction: A comparative study
Authors: Morgan Alexander B. , Gilman Jeffrey W. 
Published: December 2002

AbstractSeveral polymer‐layered silicate (clay) nanocomposites (PLSNs) were analyzed by transmission electron microscopy (TEM) and wide‐angle X‐ray diffraction (XRD) in an effort to characterize the nanoscale dispersion of the layered silicate. The PLSNs investigated included thermoset (cyanate esters) and thermoplastic polymers (polystyrene, nylon 6, and polypropylene‐g‐maleic anhydride). The results of this study reveal that the overall nanoscale dispersion of the clay in the polymer is best described by TEM, especially when mixed morphologies are present. XRD is useful for the measurement of d‐spacings in intercalated systems but cannot always observe low clay loadings (<5%) or be used as a method to identify an exfoliated nanocomposite where no XRD peaks are present (constituting a negative result). Most importantly, the study showed that XRD is not a stand‐alone technique, and it should be used in conjunction with TEM. Our studies suggest that new definitions, or a clarification of existing definitions, are needed to properly describe the diversity of PLSN nanostructures seen in various materials. Published 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1329–1338, 2003
Extension of Peto's Test by Attribution of Tumor Lethality in the Absence of Cause‐of‐Death Information
Authors: Moon Hojin , Ahn Hongshik , Kodell Ralph L. 
Published: December 2002

AbstractA new statistical testing approach is developed for rodent tumorigenicity assays that have a single terminal sacrifice or occasionally interim sacrifices but not cause‐of‐death data. For experiments that lack cause‐of‐death data, statistically imputed numbers of fatal tumors and incidental tumors are used to modify Peto's cause‐of‐death test which is usually implemented using pathologist‐assigned cause‐of‐death information. The numbers of fatal tumors are estimated using a constrained nonparametric maximum likelihood estimation method. A new Newton‐based approach under inequality constraints is proposed for finding the global maximum likelihood estimates. In this study, the proposed method is concentrated on data with a single sacrifice experiment without implementing further assumptions. The new testing approach may be more reliable than Peto's test because of the potential for a misclassification of cause‐of‐death by pathologists. A Monte Carlo simulation study for the proposed test is conducted to assess size and power of the test. Asymptotic normality for the statistic of the proposed test is also investigated. The proposed testing approach is illustrated using a real data set.
Influence of hydrogen on SiO2 thick film deposited by PECVD and FHD for silica optical waveguide
Authors: Kim Y.T. , Cho S.M. , Seo Y.G. , Yoon H.D. , Im Y.M. , Yoon D.H. 
Published: December 2002

AbstractSilicon dioxide (SiO2) thick films have been deposited by plasma enhanced chemical vapor deposition (PECVD) and flame hydrolysis deposition (FHD). PECVD SiO2 films were obtained at low temperatures (<350 °C) by the decomposition of the appropriate mixture of (SiH4+N2O) gases under suitable rf power and N2O/SiH4 ratio. For low N2O/SiH4 ratio, a refractive index(n) value close to 1.50 is obtained. The deposition rate increased with the increase of rf power. FHD SiO2 films were produced by the flame hydrolysis reaction of halide materials such as SiCl4, POCl3 and BCl3 in an oxy‐hydrogen torch. The porous SiO2 layer, under the POCl3/BCl3 ratio deposition condition, has to be consolidated by annealing at around 1300 °C.
Anharmonicity in GaTe layered crystals
Authors: Aydinli A. , Gasanly N.M. , Uka A. , Efeoglu H. 
Published: December 2002

AbstractThe temperature dependencies (10‐300 K) of seven Raman‐active mode frequencies in layered semiconductor gallium telluride have been measured in the frequency range from 25 to 300 cm‐1. Softening and broadening of the optical phonon lines are observed with increasing temperature. Comparison between the experimental data and theories of the shift of the phonon lines during heating of the crystal showed that the experimental dependencies can be explained by contributions from thermal expansion and lattice anharmonicity. Lattice anharmonicity is determined to be due to threephonon processes.
Structure and electrochemical behaviour of Bis[N‐(4‐methylphenyl)salicylaldimine]copper(II) N,N′dimethylformamide solvate
Authors: Tatar Yildirim L. , Emregul K. C. , Kurtaran R. , Atakol O. 
Published: December 2002

AbstractThe molecular model of mononuclear complex formed, through a reaction between N‐(4‐methylphenyl)salicylaldimine and CuII ion was determined using x‐ray diffraction method. The CuII coordination was found to have a distorted square‐planar structure and a cis coordination geometry was observed within the surrounding of the copper. The electro chemical behaviour of the mononuclear copper complex was studied with cyclic voltammetry.
Current sensorless speed servo system of a PM motor based on the current estimation method
Authors: Ohishi Kiyoshi , Nakamura Yusuke 
Published: December 2002

AbstractThis paper proposes a new speed servo system for a PM motor without a current sensor, which is constructed by the current simulator of a PM motor. The proposed speed servo system is simple and economical. The sensor of the proposed system is only a position sensor used as an encoder. Hence, the proposed speed servo system has little influence on the switching noise of a PWM inverter. Moreover, the resolution of the proposed current simulator can be higher than that of the conventional actual feedback system.In this paper, the experimental results point out that the proposed current sensorless speed servo system has the desired current and speed response. The current waveform of the proposed system is smooth and clean. Moreover, this paper proposes a new identification algorithm for motor resistance Ra and main flux Φfa by using only a position sensor. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 64–73, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10084
High‐field electrical properties under AC voltage application in acetophenone‐coated LDPE film
Authors: Mitsumoto Shin'ichi , Nagao Masayuki , Fukuma Masumi , Hozumi Naohiro 
Published: December 2002

AbstractThis paper deals with the effects of acetophenone coating on dielectric properties such as tan δ and capacitance and on space charge formation up to electrical breakdown under AC voltage application in low‐density polyethylene (LDPE) film. The existence of acetophenone at the electrical interface enhances tan δ. tan δ in acetophenone‐coated specimens increased with electric field and decreased with the frequency in the high‐field and high‐temperature region. AC breakdown test revealed that the electric strength in noncoated specimens was higher than in acetophenone‐coated specimens, and that the electric strength also decreased with temperature. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 1–7, 2003; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/eej.10086
Development of a new adaptive LQG system generator for high‐speed damping control techniques of power system oscillation
Authors: Michigami Tsutomu , Terasaki Masaru , Sasazima Nobuyoshi , Hayashi Kunitake , Okamoto Takashi 
Published: December 2002

AbstractWith the advent of interconnection of large‐scale electric power systems, many new dynamics power system problems have emerged, which include low‐frequency intersystem oscillations and many others. To date, most major generators in trunk electric power systems in Japan are equipped with supplementary excitation control, commonly referred to as the conventional single and two input PSS. However, low‐frequency oscillations still occur. It is difficult for these conventional PSS to improve the additional damping of power system oscillation, because of the hardware and design of fixed PSS control constants from a one‐machine infinite‐bus model. It has therefore become necessary to develop a new adaptive LQG system generator. This paper explains the development of the new adaptive LQG system and the simulation of low‐frequency and local mode oscillation for this new adaptive LQG system. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 30–40, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10109
A study of the occurrence mechanism for undershoot of logic signal
Authors: Toyoda Keiji 
Published: December 2002

AbstractWaveform distortion of logic signal caused by accelerated clock speed and increased implementation density causes nonlinear output and has been responsible for behavioral problems in electronic systems, including the overshoot type, hysteresis type, and undershoot type of transient waveform distortion. Deep undershoot could cause latchup of CMOS logic ICs, data destruction in DRAM, and pulse splitting in TTL ICs. Undershoot of logic signals is discussed in terms of both transient phenomena (time domain) and filter theory (frequency domain). Variation of the resistance R caused by output circuit impedance variation creates time domain variations in such quantities as the damping constant α and damping coefficient ζ, while variation of resistance R creates Q variation in the frequency domain.This paper describes a mechanism by which undershoot occurs when parasitic series resonance circuits are formed on the load side of the driving device and the damping coefficient ζ varies time‐sequentially in totem‐pole or complementary circuits. PSpice simulation suggests that undershoot can be reduced by controlling the phase of the punchthrough current. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 142(3): 41–48, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10141
Peak broadening in microchip electrophoresis: A discussion of the theoretical background
Authors: Gaš Bohuslav , Kenndler Ernst 
Published: December 2002

AbstractA review on peak (band, zone) broadening in electromigration separation methods is presented, mainly covering articles published between the begining of 2000 and middle of 2002. Most attention is drawn to work dealing with microchip electrophoresis performed in micrototal analysis systems (μTAS) or the lab‐on‐a‐chip, but many of the results are significant for capillary zone electrophoresis in general. The paper reviews the theoretical background of the peak dispersion due to the geometry of the separation channel, the transversal nonhomogeneity of the electroosmootic flow, and electromigration dispersion (sample overload) connected with the occurrence of the system zones (system peaks, system eigenpeaks).
Recent advances in capillary isoelectric focusing: 1997–2001
Authors: Shimura Kiyohito 
Published: December 2002

AbstractThe methodological developments in the field of capillary isoelectric focusing (CIEF) published between 1997–2001 are reviewed as a continuation of the previous review by Rodriguez‐Diaz et al. (Electrophoresis 1997, 18, 2134–2144). The applications are summarized and the progress in CIEF technologies, including experimental setup with coated and uncoated capillaries, remedies for the presence of salts in samples, additives to reduce precipitation of samples during the focusing process, calibration of the pH gradients, issues of reproducibility, carrier ampholyte‐free CIEF, and a computer simulation of focusing process are discussed. Developments of IEF separations in fabricated microchannels and the advances in detection schemes, i.e., imaging, fluorescence and chemiluminescence, are summarized. The progress in micropreparation was noted, and the massive works for two‐dimensional separations are described for the coupling with size‐exclusion chromatography and mass spectrometry, in which the developments aimed at proteomics are discussed separately. The applications for the detection of noncovalent complexes and the separations of microorganisms are reviewed.