bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methods for removal of residual catalyst from polymers prepared by ring opening metathesis polymerization
Authors: Lambeth Robert H. , Pederson Samuel J. , Baranoski Myvan , Rawlett Adam M. 
Published: October 2010

AbstractMethods for removing the residual Grubbs' third generation catalyst from polymers prepared by ring opening metathesis polymerization are reported. Two strategies were investigated for reduction of the residual catalyst in the final polymer product. The first strategy involved the use of heterogeneous functionalized particles to scavenge the catalyst from the solution. Filtration of the particles followed by precipitation produced polymers with 10–60 ppm residual catalyst, depending on the type of particle used, surface functional groups, and number of equivalents. The second strategy used small organic molecules that could coordinate to the metal species and modify the solubility of the catalyst, facilitating partitioning of the catalyst into the precipitation solvent. Several types of molecules with varied functionality reduced the residual catalyst level to 30–120 ppm, depending on the loading. Hydrogenation of the polymer backbone followed by precipitation lowered the residual Ru content from 195 ppm to 10 ppm, suggesting that the difficulty of completely removing the catalyst could be a result of coordination of the metal species to the double bonds in the polymer backbone. Reducing the amount of trace catalyst significantly improved the oxidative stability of the polymer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Grafting polymerization of styrene onto alternating terpolymers based on chlorotrifluoroethylene, hexafluoropropylene, and vinyl ethers, and their modification into ionomers bearing ammonium side‐groups
Authors: Valade David , Boschet Frédéric , Ameduri Bruno 
Published: October 2010

AbstractThe grafting polymerization of styrene initiated by the alkyl chloride groups of poly(CTFE‐alt‐VE) and poly[(CTFE‐alt‐VE)‐co‐(HFP‐alt‐VE] copolymers (where CTFE, HFP, and VE stand for chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), and vinyl ether (VE), respectively) followed by the chemical modification of the polystyrene grafts are presented. First, the fluorinated alternating copolymers were produced by radical copolymerization of CTFE (with HFP) and VE. Second, atom transfer radical polymerization enabled the grafting polymerization of styrene in the presence of the poly(CTFE‐alt‐VE)‐macroinitiator using the alkyl chloride group of CTFE as the initiation site. Kinetics of the styrene polymerization indicated that such a grafting had a certain controlled character. For the first time, grafting of polystyrene onto alternating fluorinated copolymers has been achieved. Differential scanning calorimetry thermograms of these graft copolymers exhibited two glass transition temperatures assigned to both amorphous domains of the polymeric fluorobackbone (ranging from −20 to +56 °C) and the polystyrene grafts (ca. 95 °C). The thermostability of these copolymers increased on grafting. Thermal degradation temperatures at 5% weight loss were ranging from 193 to 305 °C when the polystyrene content varied from 81 to 27%. Third, chloromethylation of the polystyrene grafts followed by the cationization of the chloromethyl dangling groups led to original ammonium‐containing graft copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis and characterization of novel low‐bandgap triphenylamine‐based conjugated polymers with main‐chain donors and pendent acceptors for organic photovoltaics
Authors: Sahu Duryodhan , Padhy Harihara , Patra Dhananjaya , Huang Jen‐hsien , Chu Chih‐wei , Lin Hong‐Cheu 
Published: October 2010

AbstractA series of novel low‐bandgap triphenylamine‐based conjugated polymers (PCAZCN, PPTZCN, and PDTPCN) consisting of different electron‐rich donor main chains (N‐alkyl‐2,7‐carbazole, phenothiazine, and cyclopentadithinopyrol, respectively) as well as cyano‐ and dicyano‐vinyl electron‐acceptor pendants were synthesized and developed for polymer solar cell applications. The polymers covered broad absorption spectra of 400–800 nm with narrow optical bandgaps ranging 1.66–1.72 eV. The highest occupied molecular orbital and lowest unoccupied molecular orbital levels of the polymers measured by cyclic voltammetry were found in the range of −5.12 to −5.32 V and −3.45 to −3.55 eV, respectively. Under 100 mW/cm2 of AM 1.5 white‐light illumination, bulk heterojunction photovoltaic devices composing of an active layer of electron‐donor polymers (PCAZCN, PPTZCN, and PDTPCN) blended with electron‐acceptor [6,6]‐phenyl‐C61‐butyric acid methyl ester or [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM) in different weight ratios were investigated. The photovoltaic device containing donor PCAZCN and acceptor PC71BM in 1:2 weight ratio showed the highest power conversion efficiency of 1.28%, with Voc = 0.81 V, Jsc = 4.93 mA/cm2, and fill factor = 32.1%. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Stimulated emission and ultrafast optical switching in a ter(9,9′‐spirobifluorene)‐co‐methylmethacrylate copolymer
Authors: Charas Ana , Mendonça A. Luísa , Clark Jenny , Bazzana Luca , Nocivelli Alessandro , Lanzani Guglielmo , Morgado Jorge 
Published: October 2010

AbstractA methacrylate‐functionalized 9,9′‐spirobifluorene trimer is copolymerized with methylmethacrylate (MMA). The photophysical characterization of this copolymer using pump‐probe studies, in solution, as films and in plastic optical fibers (POFs) demonstrates that it shows interesting photonic properties for data communication such as high‐stimulated emission cross section (σSE = 2.5 × 10−16 cm2), good thermal, and optical stability, the ability to perform all‐optical ultrafast switching, and low attenuation when doped into POFs. In addition, the material shows interesting optically induced conformational control in solution and the studies demonstrate the surprising result that intrachain polaron pairs can be generated even in well‐isolated 3‐unit oligomers. Although the material is not yet soluble enough in MMA to create highly efficient photonic devices and the gain spectrum is not optimized to overlap with the region of low attenuation in polymethylmethacrylate POFs, these studies are a good starting point to further optimize copolymers for incorporation into POF networks. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
The effect of annealing conditions on the intercalation and exfoliation of layered silicates in polymer nanocomposites
Authors: Ceccia Simona , Bellucci Federica , Monticelli Orietta , Frache Alberto , Traverso Giuliano , Casale Antonio 
Published: October 2010

AbstractLayered silicate nanocomposites based on polyamide 6 and polypropylene have been prepared via static annealing experiments. The evolution of clay dispersion into the polymer matrices was monitored by wide angle X‐ray diffraction analysis and transmission electron microscopy. The results have evidenced that the polymer diffusion inside the organoclay galleries is spontaneous and have elucidated the mechanism of nanostructured system formation under static conditions. Indeed, the exfoliation mechanism turned to be a two‐step process consisting of polymer intercalation into the clay galleries and progressive layer delamination. Both steps have turned out to depend on thermodynamic and kinetic parameters. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
Thermal properties and influence of orientation on crystalline morphologies in stereoblock polypropylene and related elastomers
Authors: Sauer Bryan B. , Kampert William G. , Mclean R. Scott , Monteiro Raisa 
Published: October 2010

AbstractAtomic force microscopy (AFM), small angle X‐ray scattering (SAXS), temperature modulated differential scanning calorimetry (TMDSC), variable heating rate DSC, an independent rapid heating rate method for melting points, and cyclic mechanical testing were used to study semicrystalline thermoplastic elastomeric polypropylenes (ELPPs) and related semicrystalline polyolefins including ethylene copolymers. Low crystallinity (ca., 9 and 15%) ELPP samples were studied by AFM in the nonoriented and melt‐oriented states. AFM images taken as a function of time after quenching of a melt‐drawn and highly nucleated film resolved details of secondary crystallization involving lateral growth on the ordered row‐nucleated structures. For nonoriented films, isothermal melt crystallization at high temperatures (110 °C) led to similar features for the two ELPPs. The dominant crystalline morphology studied by AFM consisted of small (several nm in width) granular crystallites organized into immature but large spherulites spanning tens of microns. A striking cross‐hatch morphology was detected in regions of the surface in 110 °C crystallized samples, which is contrasted with melt‐drawn films where row nucleated structures dominated the morphology in the film under no external stress. AFM was also used to monitor the morphological changes that occurred as the films were stretched at 25 °C. Break‐down of lamellae was observed, resulting in oriented narrow fibrils. Cyclic stress‐strain curves showed the expected result where lower crystallinity ELPPs had higher recoverable levels of set after both 100 and 500% elongation. TMDSC was used to resolve the broad melting and recrystallization regions in these low to medium crystallinity ELPP systems, and to contrast the results with ethylene copolymers. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011
Generalized geometry and partial supersymmetry breaking
Authors: Triendl H. 
Published: October 2010

AbstractThis review article consists of two parts. In the first part we use the formalism of (exceptional) generalized geometry to derive the scalar field space of SU(2) × SU(2)‐structure compactifications. We show that in contrast to SU(3) × SU(3) structures, there is no dynamical SU(2) × SU(2) structure interpolating between an SU(2) structure and an identity structure. Furthermore, we derive the scalar manifold of the low‐energy effective action for consistent Kaluza‐Klein truncations as expected from 𝒩 = 4 supergravity. In the second part we then determine the general conditions for the existence of stable Minkowski and AdS 𝒩=1 vacua in spontaneously broken gauged 𝒩 = 2 supergravities and construct the general solution under the assumption that two appropriate commuting isometries exist in the hypermultiplet sector. Furthermore, we derive the low‐energy effective action below the scale of partial supersymmetry breaking and show that it satisfies the constraints of 𝒩 = 1 supergravity. We then apply the discussion to special quaternionic‐Kähler geometries which appear in the low‐energy limit of SU(3) × SU(3)‐structure compactifications and construct Killing vectors with the right properties. Finally we discuss the string theory realizations for these solutions.
A course for clinical trial personnel in clinical study designs, randomization, allocation schedules, and interactive response systems
Authors: Golm Gregory T. , Bradstreet Thomas E. , Coffey Laura A. 
Published: October 2010

AbstractThis continuing education course for professionals involved in all areas of clinical trials integrates concepts related to the role of randomization in the scientific process. The course includes two interactive lecture and discussion sections and a workshop practicum. The first interactive lecture introduces basic clinical trial issues and statistical principles such as bias, blinding, randomization, control groups, and the importance of formulating clear and discriminating clinical and statistical hypotheses. It then focuses on the most commonly used clinical study designs and the corresponding patient randomization schemes. The second interactive lecture focuses on the implementation of randomization of patients and drug supply through allocation and component ID schedules. The workshop practicum, conducted in small groups, enables students to apply the lecture concepts to real clinical studies. Flexibility was built into the workshop practicum materials to allow the course content to be customized to specific audiences, and the interactive lecture sessions can be stretched to cover more advanced topics according to class interest and time availability. Copyright © 2010 John Wiley & Sons, Ltd.
Review of the statistical analysis of the dog telemetry study
Authors: Aylott Mike , Bate Simon , Collins Susie , Jarvis Philip , Saul Jim 
Published: October 2010

AbstractIn 2008, the PSI Toxicology Special Interest Group met to discuss the design and analysis of dog telemetry studies. The dog telemetry study is one component of the integrated cardiovascular assessment required by regulatory bodies. Although there are guidelines for these studies, little is said about the statistical analysis. With parameters of interest measured continually over time, in studies typically involving four dogs, the analysis is not straightforward. This has led to many different types of analysis being proposed in the literature, with many different methods applied within the pharmaceutical industry itself. This paper summarizes the PSI Toxicology group's discussions and recommendations around these issues. Copyright © 2010 John Wiley & Sons, Ltd.
Usage space analysis for reliability testing
Authors: Haselgruber Nikolaus , Mautner Karin , Thiele Jan 
Published: October 2010

AbstractDuring the development process of a complex technical product, one widely used and important technique is accelerated testing where the applied stress on a component is chosen to exceed the reference stress, i.e. the stress encountered in field operation, in order to reduce the time to failure. For that, the reference stress has to be known. Since a complex technical product may fail regarding numerous failure modes, stress in general is highly dimensional rather than scalar. In addition, customers use their products individually, i.e. field operation should be described by a distribution rather than by one scalar stress value. In this paper, a way to span the customer usage space is shown. It allows the identification of worst case reference stress profiles in significantly reduced dimensions with minimal loss of information. The application example shows that even for a complex product like a combustion engine, stress information can be compressed significantly. With low measurement effort it turned out that only three reference stress cycles were sufficient to cover a broad range of customer stress variety. Copyright © 2010 John Wiley & Sons, Ltd.
Bag‐of‐words‐driven, single‐camera simultaneous localization and mapping
Authors: Botterill Tom , Mills Steven , Green Richard 
Published: October 2010

AbstractThis paper describes BoWSLAM, a scheme for a robot to reliably navigate and map previously unknown environments, in real time, using monocular vision alone. BoWSLAM can navigate challenging dynamic and self‐similar environments and can recover from gross errors. Key innovations allowing this include new uses for the bag‐of‐words image representation; this is used to select the best set of frames from which to reconstruct positions and to give efficient wide‐baseline correspondences between many pairs of frames, providing multiple position hypotheses. A graph‐based representation of these position hypotheses enables the modeling and optimization of errors in scale in a dual graph and the selection of only reliable position estimates in the presence of gross outliers. BoWSLAM is demonstrated mapping a 25‐min, 2.5‐km trajectory through a challenging and dynamic outdoor environment without any other sensor input, considerably farther than previous single‐camera simultaneous localization and mapping (SLAM) schemes. © 2010 Wiley Periodicals, Inc.
Galileo/SAR: Performance aspects and new service capabilities
Authors: Lewandowski Andreas , Niehoefer Brian , Wietfeld Christian 
Published: October 2010

AbstractThe European satellite navigation system Galileo is a highly promising technology and offers communication capabilities that can be bridled to provide an enhanced Search‐and‐Rescue (SAR) service in combination with the system, currently in service, Cospas‐Sarsat. In order to enhance the process of retrieval during a rescue operation, this article proposes a Short Messaging Service (SMS) by utilizing the existing message formats and owes of the SAR service. Architectural building blocks which are particularly belonging to either Cospas‐Sarsat or Galileo are highlighted. A new simulation method for local 3D scenarios is presented, which combines detailed 3D environment models with ray tracing and event‐based protocol simulation. Results, both in a global and local 3D setup, reflect the performance indicators of the satellite systems from which the achievable service quality of SAR‐SMS is deduced. The necessity of Galileo/SAR for highly reliable and fast applications in emergency situations is shown and a minimum number of Galileo satellites carrying SAR payload is derived. Copyright © 2010 John Wiley & Sons, Ltd.
Dual polarization MIMO in LMS broadcasting systems: Possible benefits and challenges
Authors: Arapoglou Pantelis‐Daniel , Zamkotsian Martin , Cottis Panayotis 
Published: October 2010

AbstractThe benefits of employing dual polarization in wireless multiple‐input multiple‐output (MIMO) communication systems are only recently becoming apparent due to the continuous measurement and modeling efforts by the terrestrial research community. Land mobile satellite (LMS) broadcasting systems exhibit distinct channel, system and geometrical characteristics and are subjected to stringent spatial limitations compared to terrestrial wireless. Therefore, it remains to be investigated which operating conditions favor the joint instead of the independent encoding/decoding over the two polarizations of satellite beams. After outlining the relevant progress made in wireless dual polarization MIMO systems, the present work carries out a thorough comparison between the joint and independent encoding/decoding approaches in typical single‐satellite LMS systems exploiting state‐of‐the‐art building blocks. This comparative analysis investigates both the capacity and error performance under a fair framework between systems occupying the same resources. Since the same analytical tools are used for both terrestrial and satellite dual polarization systems, the present paper may also serve as an analytical bridge between the two. Copyright © 2010 John Wiley & Sons, Ltd.
Study on advanced nanoscale near‐field photolithography
Authors: Yang Ching‐Been , Chiang Hsiu‐Lu , Huang Jen‐Ching 
Published: October 2010

AbstractAt present, applying a near‐field optical microscope to photolithographic line segment fabrication can only obtain nanoscale line segments of equal cutting depths, and cannot result in 3D shape fabrication. This study proposes an innovative line segment fabrication model of near‐field photolithography that adjusts an optical fiber probe's field distance to control the exposure energy density, and moreover constructs an exposure energy density analysis method of the innovative photolithographic line segment fabrication. During the exposure simulation process of the innovative line segment fabrication model of near‐field photolithography, the near‐field distance between the optical fiber probe and the photoresist surface increases gradually, whereas the exposure energy density distribution decreases gradually. As a result, the cutting depth becomes shallower and the full‐width at half maximum (FWHM) increases. The results of this study can serve as a theoretical reference for developing advanced nanoscale near‐field photolithography techniques, to which an important and groundbreaking contribution is made. SCANNING 32: 351–360, 2010. © 2010 Wiley Periodicals, Inc.
Evolution of ZDDP‐derived reaction layer morphology with rubbing time
Authors: Naveira‐Suarez A. , Tomala A. , Pasaribu R. , Larsson R. , Gebeshuber I. C. 
Published: October 2010

AbstractFunctional additives, particularly extreme pressure and antiwear additives, in formulated oil will compete to adsorb and function in tribological contacts. A low‐polarity commercial base oil, poly‐α‐olefin (PAO), blended with zinc dialkyl dithiophosphates (ZDDP) has been studied. The tribological performance was evaluated using a ball‐on‐disk test rig under mixed rolling–sliding conditions in the boundary lubrication regime at 90°C. An adapted in situ interferometry technique was used to monitor the additive‐derived reaction layer formation. The thickness of the reaction layer evolves with rubbing until reaching a limiting thickness value of approximately 70 nm. The evolution of the topography and mechanical properties of the ZDDP‐derived reaction layer with rubbing time were studied using Atomic Force Microscopy. A constant roughening and hardening of the additive‐derived layer with rubbing time is observed and related to the different tribological performance of the layer at different rubbing times. SCANNING 31: 294–303, 2010. © 2010 Wiley Periodicals, Inc.
Security of the GPT cryptosystem and its applications to cryptography
Authors: Rashwan Haitham , Gabidulin Ernst M. , Honary Bahram 
Published: October 2010

AbstractThe public key cryptosystem (PKC) based on rank error correcting codes (the GPT cryptosystem) was proposed in 1991. Use of rank codes in cryptographic applications is advantageous since it is practically impossible to utilize combinatoric decoding. This enabled using public keys of a smaller size. Several attacks against this system were published, including Gibson's attacks and more recently Overbeck's attacks. A few modifications were proposed withstanding Gibson's attack but at least one of them was broken by the stronger attacks by Overbeck. A tool to prevent Overbeck's attack is presented by Gabidulin, which makes the cryptographer define a proper column scrambler matrix over the extension field without violating the standard mode of GPT cryptosystem. In this paper, we apply this tool to another variant of the GPT cryptosystem. Furthermore we increase the security of the proposed system against all known attacks and reduce the public key size to 4 Kbits instead of 10 Kbits. Copyright © 2010 John Wiley & Sons, Ltd.
Palmprint authentication using fusion of wavelet and contourlet features
Authors: Prasad S. M. , Govindan V. K. , Sathidevi P. S. 
Published: October 2010

AbstractLow resolution palmprint images consist of discriminative multisized and multidirectional principal lines and wrinkles. Intuitively, discrete wavelet transform (DWT) is a good choice to extract such patterns due to its space‐frequency localization, multiresolution analysis (MRA) capability, and computational efficiency. However, most of the DWT‐based palmprint recognition systems fail to report low equal error rate (EER) due to inherent limitations of DWT and shift‐rotational variations in the intraclass palmprint images. This paper proposes the techniques for shift and rotation invariant feature extraction using DWT extension. The effectiveness of these techniques is tested on deliberately shifted and rotated palmprints. Further, limited directionality due to DWT is overcome by augmenting with features of contourlet transform. Contourlet transform can extract curve singularities effectively with multidirectional decomposition capability; wavelets are good in extracting point singularities. The different views of contourlet transform and DWT on palmprints motivate us to extract contourlet and wavelet features, and examine them for their individual and combined verification performances. The combined mode is found to perform well over their individual performances. The average EER (0.41%), obtained on PolyU‐Online‐Palmprint‐Database‐II (PolyU), is better than the existing wavelets/transform‐based palmprint recognition approaches and comparable to the other state of the art palmprint recognition approaches. The computational burden on feature extraction and matching is substantially low thereby making the approach suitable for resource constrained environments. Copyright © 2010 John Wiley & Sons, Ltd.