bluuebunny/crossref_metadata_2025_split huggingface dataset:
Swelling behaviors of polyelectrolyte hydrogels containing sulfonate groups
Authors: Atta Ayman M. 
Published: September 2002

AbstractSeries of maleate monoester and diester monomers based on poly(ethylene glycol) monomethyl ether (MPEG) were copolymerized using the ionizable 2‐acrylamido‐2–methyl propane sulfonic acid (AMPS) via different dose rate of electron‐beam irradiation (40–150 kGy). The crosslinking of the copolymers were carried out in aqueous acidic solutions at pH 1 or in the presence of 1% N,N‐methylene bisacrylamide (MBA) as crosslinking agent. The final equilibrium water content and swelling capacities for the prepared hydrogels were determined in aqueous solutions at pH 1, 6.8, and 12 and in aqueous salt solutions at 298 K. Swelling equilibria for prepared hydrogels were determined in different molar salt solutions of NaCl, KCl, CaCl2, Na2SO4, K2SO4, and CaSO4. The swelling ratios of gels in pure water and in the salt solutions were found to depend on the counterion species in the increasing sequence of Ca2+, Na+ and K+. Copyright © 2002 John Wiley & Sons, Ltd.
Electromagnetic interference shielding by using conductive polypyrrole and metal compound coated on fabrics
Authors: Lee C. Y. , Lee D. E. , Jeong C. K. , Hong Y. K. , Shim J. H. , Joo J. , Kim M. S. , Lee J. Y. , Jeong S. H. , Byun S. W. , Zang D. S. , Yang H. G. 
Published: September 2002

AbstractElectromagnetic interference (EMI) shielding materials of complex type of conductive polypyrrole (PPy) as an intrinsically conducting polymer and silver‐palladium (AgPd) metal compound coated on woven or non‐woven fabrics are synthesized. From dc conductivity and SEM photographs of PPy/fabric complexes, we discuss charge transport mechanism and the homogeneity of coating on the fabrics. The EMI shielding efficiency of PPy/fabric and AgPd/fabric complexes is in the range of 8 ∼ 80 dB depending on the conductivity and the additional Ag vacuum evaporation. The highest EMI shielding efficiency of PPy/fabric complexes vacuum‐evaporated by Ag is ∼80 dB, indicating potential materials for military uses. We propose that PPy/fabrics are excellent RF and microwave absorber because of the relatively high absorbance and low reflectance of the materials. Copyright © 2002 John Wiley & Sons, Ltd.
Cholesteric mixture containing chiral‐photochromic and diarylethene dopants as novel material with dual photochromism
Authors: Bobrovsky A. , Boiko N. , Shibaev V. P. , Zavarzin I. , Kalik M. , Krayushkin M. 
Published: September 2002

AbstractNew cholesteric polymeric mixture containing nematic side‐chain homopolymer, 2 wt% of photochromic diarylethene dopant and 5 wt% of chiral‐photochromic dopant based on cinnamic acid and isosorbide was prepared. Upon UV irradiation of planarly‐oriented mixture films at room temperature, a transformation of open colorless form of diarylethene dopant into a closed colored form takes place, which is followed by the appearance of an intense absorption maximum in the visible spectral region and decreasing selective light reflection intensity. This process is photo‐ and thermo‐reversible and many cycles ‘recording‐erasing’ can be realized. UV irradiation and subsequent annealing of the films lead to untwisting of the cholesteric helix and cause an irreversible shift of selective light reflection to the long‐wavelength region. This process is explained by the E‐Z isomerization of chiral photochromic groups of the dopant relative to a CC bond accompanied by a decrease in their twisting ability.It has been shown, that the use of the material prepared in this work provides an opportunity to record two images at the same time: one image is due to a change in the helical pitch and another (second) image is due to the photochromism of diarylethene dopant. It is pertinent to note that using the approach developed in this work allows one to widely vary the range of materials exhibiting dual photochromism. It was demonstrated that the mixture under study shows advantage as new photosensitive material for optics, optoelectronics and data recording. Copyright © 2002 John Wiley & Sons, Ltd.
Association of British Clinical Diabetologists
Authors: Wales John , Essex Nina , Fox Charles , Singh Dev , Wroe James 
Published: September 2002

AbstractMembers of the Association of British Clinical Diabetologists (ABCD) from all over the United Kingdom met for two days in the congenial atmosphere of The Jury's Ballsbridge Hotel in Dublin to discuss two important medico‐political/professional topics: the National Service Framework for Diabetes and its implications for secondary diabetes care; and the role and responsibilities of the diabetes specialist nurse in relation to those of the diabetologist. The meeting was an opportunity also for delegates to debate the clinical significance of postprandial hyperglycaemia and to update and inform themselves through state‐of‐the‐art lectures and discussions on a range of other interesting and relevant clinical issues. Copyright © 2002 John Wiley & Sons, Ltd.
The Oxford International Diabetes Summit: Implications of the DAWN study
Authors: Roglic Gojka , Matthews David , Rubin Richard R , Bech Ole Molskov 
Published: September 2002

AbstractThe DAWN (Diabetes Attitudes, Wishes and Needs) study was instigated by Novo Nordisk in order to assess the perceptions and attitudes of people with diabetes and health care providers to the management and care of diabetes. The study was conducted between August 2000 and September 2001 in 11 countries or regions: Australia, France, Germany, India, Japan, Poland, Spain, The Netherlands, United Kingdom, Scandinavia (Denmark, Norway and Sweden) and the USA, with the focus on drivers of effective self‐management amongst over 5400 people with diabetes and over 3800 diabetes health care providers (specialist doctors, GPs and nurses).The objective of the DAWN study was to provide information of value in improving diabetes care and the well being of diabetic patients and to enhance and complement data derived from other reported psychosocial studies. To this end, the first Oxford DAWN International Summit met to consider its implications and resolve ways in which the findings of the DAWN study could be implemented. The interactive nature of the summit was enhanced by the use of computer‐linked individual keypads, so that delegates could participate interactively and vote on a range of issues. Following presentations on the key issues surrounding DAWN, a series of participant workshops considered the issues that had been raised and produced their recommendations for future action.Opening the Summit, Chairman Dr David Matthews (Chairman of the Oxford Centre for Diabetes, Endocrinology and Metabolism, Oxford, UK) commented on its multi‐national and multi‐disciplinary nature and how this was bringing together different stakeholder perspectives. Use of the keypads showed that Denmark, USA, Germany and the UK (in that order) were the best represented. Delegates included diabetologists, nurses, behavioural scientists, GPs, patients and health payors. These different perspectives would be important in arriving at conclusions. The DAWN study had endeavoured to discover the person behind the patient and to establish to what degree self‐care management truly involved a partnership between patient and health care provider. Dr Matthews emphasised the psychosocial nature of the survey and the ways in which this aspect of care had perhaps been somewhat neglected in the past. DAWN represented an opportunity for change; this challenge should be welcomed. He hoped that the outcome of the summit would have a long lasting effect over the coming years. Copyright © 2002 John Wiley & Sons, Ltd.
Fast transient fluorescence technique for studying swelling of gels made at various crosslinker contents and exposed to organic vapour
Authors: Erdoǧan M , Yönel B , Pekcan Ö 
Published: September 2002

AbstractFast transient fluorescence technique (FTRF) was employed for studying swelling of disc‐shaped poly(methyl methacrylate) (PMMA) gels, which were prepared by free radical copolymerization of methyl methacrylate (MMA) using various ethylene glycol dimethacrylate (EGDM) contents at 60 °C. Pyrene (P) was introduced as a fluorescence probe during polymerization. Swelling experiments were performed by using P‐doped PMMA gels under chloroform vapor. Decay curves of P were measured during in situ swelling experiments. Exponential fits were performed to measure pyrene lifetimes, τ, inside the PMMA gels. It was observed that τ values decreased as swelling proceeded. An equation is derived for low quenching efficiencies to interpret the behaviour of P lifetimes during swelling. The Li–Tanaka equation was used to determine the cooperative diffusion coefficients, Dc, for the gels made at various crosslinker contents. It is observed that Dc values decrease as the crosslinker content is increased.© 2002 Society of Chemical Industry
Structural relaxation in poly(ethylene terephthalate) studied by positron annihilation lifetime spectroscopy
Authors: Sathyanarayana P M , Shariff Gani , Thimmegowda M C , Ashalatha M B , Ramani R , Ranganathaiah C 
Published: September 2002

AbstractPositron lifetime technique was used to study the physical ageing process in poly(ethylene terephthalate) (PET). Positron lifetime results show that the structural relaxation processes in PET encompass two different time regimes, one short and the other long. The relaxation function constructed from the measured o‐Ps intensity I3 exhibits non‐exponential character, which can be best fitted with two additive exponentials. The Narayanaswamy model (Kohlraush‐William Watt (KWW) function) is invoked to extract the stretching parameter β indicating the extent of deviation from exponential relaxation. Based on the relaxation times, the activation energies calculated seem to label the different kinetic units of PET structure participating in the relaxation process.© 2002 Society of Chemical Industry
Phase separation in blends of linear polymers formed in situ according to different mechanisms
Authors: Lipatov Y S , Kosyanchuk L F , Nesterov A F 
Published: September 2002

AbstractThe in situ formation of blends of two incompatible polymers was studied. The kinetics of simultaneously proceeding reactions of radical polymerization of methyl methacrylate and polyaddition reaction of polyurethane formation was investigated for various ratios of monomeric compounds in the reaction mixture. It was established that the kinetics of formation of each polymer in the mixture depends on the presence of the other and on the kinetics of its formation. These parallel reactions are accompanied by phase separation at a definite conversion degree of each monomer. The onset of phase separation does not affect the course of the kinetic curves. The regularities of phase separation in connection with reaction kinetics were investigated by light scattering. It was found that because of the difference in the rates of the two reactions, the ratio of the polymers formed in the reaction mixture continually changes in time. In spite of this, initial stages of the phase separation may be considered as proceeding according to the spinodal mechanism. Values of amplification factors were calculated which depend on the component ratio and reaction rates. It was established that reaction‐induced phase separation determines the formation of the interconnected morphology immediately after the onset of phase separation, when the composition of the polymer blends has not yet reached its equilibrium value.© 2002 Society of Chemical Industry
Active sites deterioration of MgCl2‐supported catalyst induced by the electron donor extraction by alkylaluminium
Authors: Matsuoka Hitoshi , Liu Boping , Nakatani Hisayuki , Nishiyama Isa , Terano Minoru 
Published: September 2002

AbstractTo investigate the role of the internal donor in a Ziegler–Natta catalyst, the nature and existing states of the internal donor were intentionally varied by alkylaluminium treatment before polymerization, and the catalytic properties during propene polymerization were accurately evaluated using the stopped‐flow method. A significant decrease in the amount of the remaining internal donor was observed during the initial stage of the extraction. The polymerization results show a gradual decrease in the polymer isotacticity with an increase in the extraction time. These different patterns, as a function of the extraction time, indicate that the amount of the remaining internal donor is not directly related to the isotacticity of the produced polymer.© 2002 Society of Chemical Industry
Scale‐up of adsorptive styrene drying
Authors: Rivero María J , Gorri Daniel , Ibáñez Raquel , Ortiz Inmaculada 
Published: September 2002

AbstractThis work is focused on the analysis of the scale‐up process of styrene drying by adsorption onto activated alumina as a necessary step in the manufacture of styrene–butadiene rubber. In a previous work, the mathematical model was developed and the design parameters were estimated from the fitting of the model to experimental results obtained in a laboratory set‐up. The obtained model and parameters have been used to simulate the behaviour of a pilot plant that contains up to 56 times more sorbent stating their validity after comparison with experimental results. Finally, the behaviour of an industrial plant presently at work, was also satisfactorily described. The ability of the model to simulate experimental results obtained on three different scales checks its adequacy for process design and optimization.© 2002 Society of Chemical Industry
Proton and electron radiation data and analysis of GaInP2/GaAs/Ge solar cells
Authors: Sharps P. R. , Aiken D. J. , Stan M. A. , Thang C. H. , Fatemi Navid 
Published: September 2002

AbstractWe present electron and proton radiation data for our GaInP2/GaAs/Ge triple‐junction solar cell. An analysis of the data is also done with both the relative damage coefficients (RDC) method developed at NASA‐JPL, as well as the displacement damage dose (D3) method developed by the Naval Research Laboratory. We also discuss radiation tolerance of cells in the light of our development of an advanced triple‐junction cell. Copyright © 2002 John Wiley & Sons, Ltd.
Space and terrestrial photovoltaics: synergy and diversity
Authors: Bailey Sheila G. , Raffaelle Ryne , Emery Keith 
Published: September 2002

AbstractA historical view of the research and development in photovoltaics from the perspective of both the terrestrial and the space communities is presented from the early days through the 1970s and 1980s, 1990s and beyond. The synergy of both communities, both at the beginning and in the present, and hopefully in the future, are highlighted, with examples of the important features in each program. The space community which was impressed by the light weight and reliability of photovoltaics drove much of the early development. Even today, nearly every satellite and other scientific space probe that has been launched has included some solar power. However, since the cost of these power systems was only a small fraction of the satellite and launch cost, the use of much of this technology in the terrestrial marketplace was not feasible. It was clear that the focus of the terrestrial community would be best served by reducing costs. This would include addressing a variety of manufacturing issues and raising the rate of production. Success in these programs and a resulting globalization of effort resulted in major strides in the reduction of PV module costs and increased production. Although, the space community derived benefit from some of these advances, its focus was on pushing the envelope with regard to cell efficiency. The gap between theoretical efficiencies and experimental efficiencies for silicon, gallium arsenide and indium phosphide became almost nonexistent. Recent work by both communities have focused on the development thin‐film cells of amorphous silicon, CuInSe2and CdTe. These cells hold the promise of lower costs for the terrestrial community as well as possible flexible substrates, better radiation resistance, and higher specific power for the space community. It is predicted that future trends in both communities will be directed toward advances through the application of nanotechnology. A picture is emerging in which the space and terrestrial solar cell communities shall once again share many common goals and, in fact, companies may manufacture both space and terrestrial solar cells in III–V materials and thin‐film materials. Basic photovoltaics research, including these current trends in nanotechnology, provides a valuable service for both worlds in that fundamental understanding of cell processes is still vitally important, particularly with new materials or new cell structures. It is entirely possible that one day we might have one solar array design that will meet the criteria for success in both space and on the Earth or perhaps the Moon or Mars. Published in 2002 by John Wiley & Sons, Ltd.
Nonlinear characteristics of the quantitative relationship between the glass‐transition temperature and the structure of homopolymers
Authors: Sun Hong , Tang Yingwu , Zhang Fushi , Wu Guoshi , Chan Shek‐Kiu 
Published: September 2002

AbstractFuzzy set theory was used to study the relationship between the glass‐transition temperature (Tg) and structure of homopolymers. The method can map the relationship and give the Tg for 235 polymers with a standard deviation of 8 K (the confidence bound was 90%). The entropy of the fuzziness was used to quantitatively describe the interactions among groups. The method was used to predict the Tg of 10 polymers not included in the 235 polymers, with a standard deviation of 9 K (the confidence bound was 90%). The study demonstrates again that fuzzy set theory can be effectively used to investigate the quantitative structure–property relationship of polymers. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2164–2169, 2002
Effect of aqueous and organic solutions on the performance of polyamide thin‐film‐composite nanofiltration membranes
Authors: Kim In‐Chul , Jegal Jonggeon , Lee Kew‐Ho 
Published: September 2002

AbstractPolyamide/polyacrylonitrile thin‐film‐composite (TFC) nanofiltration (NF) membranes for the separation of oleic acid dissolved in organic solvents (methanol and acetone) were interfacially prepared by the reaction of trimesoyl chloride in an organic phase with an aqueous phase containing piperazine and m‐phenylene diamine. The interfacial reaction was confirmed by an investigation of the attenuated total reflection infrared spectrum. The surface morphology of the polyamide TFC membranes was examined with scanning electron microscopy. The hydrophilic properties of the membrane surfaces were conjectured on the basis of the ζ potential and contact angle. The effects of the monomer concentrations of the monomer blends (aliphatic and aromatic diamines) and drying times on various aspects of membrane performance, such as the solvents (water, alcohols, ketones, and hexane), permeation rates, and organic solute [poly(ethylene glycol) 200 and oleic acid] rejection rates, were investigated. All the membranes showed good solvent resistance. The polar solvent flux for water and methanol was higher than that for a nonpolar solvent (hexane). The membranes gave good rejection rates of oleic acid dissolved in methanol and acetone. The NF membranes were compared with various commercial membranes. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2151–2163, 2002
Pore size distributions in low‐k dielectric thin films from X‐ray porosimetry
Authors: Lee Hae‐Jeong , Soles Christopher L. , Liu Da‐Wei , Bauer Barry J. , Wu Wen‐Li 
Published: September 2002

AbstractX‐ray reflectivity has been used to determine the mass uptake of probe molecules in porous thin films supported on thick silicon wafers. The adsorption occurs by capillary condensation when the films are exposed to probe vapor at controlled partial vapor pressures. The probe solvent partial pressure was varied by mixing saturated air and dry air at constant temperature or by changing sample temperature at a constant vapor concentration. Pore size distribution in the films can be calculated from the probe uptake with typical porosimetric approaches such as the application of the Kelvin equation to convert partial pressure into pore size. For illustration, the pore size distribution of three different nanoporous thin films, the primary candidate of ultra‐low‐k interlevel dielectrics in the next generation of integrated circuit chips, was determined with this technique. These samples represent different generations of low‐k dielectrics developed by industry. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2170–2177, 2002
Gas permeability and n‐butane solubility of poly(1‐trimethylgermyl‐1‐propyne)
Authors: Nagai Kazukiyo , Toy Lora G. , Freeman Benny D. , Teraguchi Masahiro , Kwak Giseop , Masuda Toshio , Pinnau Ingo 
Published: September 2002

AbstractThe gas permeability and n‐butane solubility in glassy poly(1‐trimethylgermyl‐1‐propyne) (PTMGP) are reported. As synthesized, the PTMGP product contains two fractions: (1) one that is insoluble in toluene and soluble only in carbon disulfide (the toluene‐insoluble polymer) and (2) one that is soluble in both toluene and carbon disulfide (the toluene‐soluble polymer). In as‐cast films, the gas permeability and n‐butane solubility are higher in films prepared from the toluene‐soluble polymer (particularly in those films cast from toluene) than in films prepared from the toluene‐insoluble polymer and increase to a maximum in both fractions after methanol conditioning. For example, in as‐cast films prepared from carbon disulfide, the oxygen permeability at 35 °C is 330 × 10−10 cm3 (STP) cm/(cm2 s cmHg) for the toluene‐soluble polymer and 73 × 10−10 cm3 (STP) cm/(cm2 s cmHg) for the toluene‐insoluble polymer. After these films are conditioned in methanol, the oxygen permeability increases to 5200 × 10−10 cm3 (STP) cm/(cm2 s cmHg) for the toluene‐soluble polymer and 6200 × 10−10 cm3 (STP) cm/(cm2 s cmHg) for the toluene‐insoluble polymer. The rankings of the fractional free volume and nonequilibrium excess free volume in the various PTMGP films are consistent with the measured gas permeability and n‐butane solubility values. Methanol conditioning increases gas permeability and n‐butane solubility of as‐cast PTMGP films, regardless of the polymer fraction type and casting solvent used, and minimizes the permeability and solubility differences between the various films (i.e., the permeability and solubility values of all conditioned PTMGP films are similar). © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2228–2236, 2002