bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultrafast photonic crystal lasers
Authors: Englund D. , Altug H. , Ellis B. , Vučković J. 
Published: July 2008

AbstractWe describe recent progress in photonic crystal nanocavity lasers with an emphasis on our recent results on ultrafast pulse generation. These lasers produce pulses on the picosecond scale, corresponding to only hundreds of optical cycles. We describe laser dynamics in optically pumped single cavities and in coupled cavity arrays, at low and room temperature. Such ultrafast, efficient, and compact lasers show great promise for applications in high‐speed communications, information processing, and on‐chip optical interconnects.
Modelling of laser surface alloying and dispersing of ceramics
Authors: Rohde M. , Dimitrova D. 
Published: July 2008

AbstractLaser‐supported processes can be used to modify the electrical and thermal properties of ceramic substrates locally. These processes are characterized by a strong thermal interaction between the laser beam and the ceramic surface that leads to localized melting. During the dynamic melting process an additive material is injected into the melt pool in order to modify the physical properties. The heat and mass transfer during this dynamic melting and solidification process has been studied numerically in order to identify the dominating process parameters. Simulation tools based on a finite‐volume method have been developed to describe the heat transfer, fluid flow and the phase change during the melting and solidification of the ceramic. The results of the calculation have been validated against experimental results.
Probing the Effects of Hydrophilic Branch Size, Distribution, and Connectivity in Amphiphilic Polyethylene
Authors: Berda Erik B. , Wagener Kenneth B. 
Published: July 2008

AbstractAcyclic diene metathesis (ADMET) polymerization/hydrogenation methodology was used to synthesize a family of amphiphilic polyethylenes (PEs) with precisely placed poly(ethylene glycol) branches. Four structural parameters are varied in this report: size of the hydrophilic pendant group, manner in which the pendant group is connected to the backbone, distance between the pendant moieties along the backbone, and saturation of the polyolefin backbone. Varying the branch size with other parameters held constant results in negligible effects on thermal behavior. However, when either the distribution of branches or manner of connection of the branches is altered, changes in the thermal behavior become clear. These slight structural changes allow tunability of the structural morphology from fully amorphous to semicrystalline materials melting over a range of temperatures above 60 °C.magnified image
Tetraalkylammonium Salts of Amino Acids and Sulfur‐Containing Amino Acids as Effective Co‐Initiators of Free Radical Polymerization in the Presence of Aromatic Ketones
Authors: Ścigalski Franciszek , Pączkowski Jerzy 
Published: July 2008

AbstractPhotoredox pairs, composed of xanthone or thioxanthone derivatives acting as light absorbers and tetrabutylammonium salts of amino acids or sulfur‐containing amino acids as co‐initiators, were studied as photoinitiators for free‐radical polymerization. The mechanism of free‐radical formation was established using the laser flash photolysis. Measurements of polymerization kinetics show that the photoinitiation ability of the xanthone‐ or thioxanthone‐derivative/amino acid or sulfur‐containing amino acid pairs depends on the initiator and co‐initiator properties, mostly on the triplet state lifetime of xanthone or thioxanthone derivatives.magnified image
Polymers that Contain Ligated Metals in their Side Chain: Building a Foundation for Functional Materials in Opto‐Electronic Applications with an Emphasis on Lanthanide Ions
Authors: Shunmugam Raja , Tew Gregory N. 
Published: July 2008

AbstractOrganic polymers that contain ligated metals offer a variety of unique properties which include luminescence, electro‐ and photochemistry, catalysis, charge, magnetism, and thermochromism. These organic–inorganic hybrid materials have the potential to offer novel active matrixes for advanced devices. Continued progress in synthetic chemistry and molecular characterization will enable such advanced materials. Here the focus is restricted to side‐chain metal complexes with emissive properties that highlight the use of lanthanide ions as opposed to the often‐studied transition metal complexes.magnified image
Facile Synthesis of Polyaniline‐Polypyrrole Nanofibers for Application in Chemical Deposition of Metal Nanoparticles
Authors: Xu Ping , Han Xijiang , Wang Chao , Zhang Bin , Wang Xiaohong , Wang Hsing‐Lin 
Published: July 2008

AbstractPolyaniline‐polypyrrole (PANI‐PPy) nanofibers with high aspect ratios have been synthesized by a one‐step, surfactant‐assisted chemical oxidative polymerization from mixtures of aniline (An) and pyrrole (Py) monomers. PANI‐PPy nanofibers synthesized with an excess of either PANI or PPy show similar spectral (UV‐vis and FT‐IR) characteristics as the individual homopolymers, whereas nanofibers from an equimolar mixture of An and Py display unique spectral characteristics. PANI‐PPy nanofibers undergo a spontaneous redox reaction with metal ions to produce metal nanoparticles with various morphologies and/or sizes. These findings may open new opportunities for synthesizing functional polymer nanofibers and metal nanoparticles with controllable sizes and/or morphologies.magnified image
High Conductivity PEDOT Using Humidity Facilitated Vacuum Vapour Phase Polymerisation
Authors: Fabretto Manrico , Zuber Kamil , Hall Colin , Murphy Peter 
Published: July 2008

AbstractThe synthesis of high conductivity poly(3,4‐ethylenedioxythiophene) (PEDOT) films using vacuum vapour phase polymerisation is reported. Water vapour is introduced into the chamber and results suggest that it acts as a proton scavenger during polymerisation. Process optimisation leads to PEDOT films that have high conductivity and a blue‐black appearance. Poor quality films have lower conductivity and a characteristic greenish colour. UV‐vis‐NIR spectra show that poor PEDOT films are characterised by higher absorption in the UV‐vis region and an absorption plateau in the NIR region, which suggests an increased level of disrupted conjugation along the polymer backbone or higher oligomer content. Conversely, high quality PEDOT is characterised by an extended NIR absorption tail and lower absorption in the UV‐vis region.magnified image
Stereoselective Interaction between Isotactic and Optically Active Poly(lactic acid) and Phenyl‐Substituted Poly(lactic acid)
Authors: Tsuji Hideto , Matsuoka Hiroshi 
Published: July 2008

AbstractIsotactic and optically active poly(D‐lactic acid) (PDLA) and phenyl‐substituted poly(lactic acid)s (Ph‐PLAs), i.e., poly(D‐phenyllactic acid) (Ph‐PDLA) and poly(L‐phenyllactic acid) (Ph‐PLLA), were synthesized and stereospecific interactions between the synthesized polymers were investigated by their thermal properties and crystallization behavior using differential scanning calorimetry (DSC). The DSC measurements indicated that PDLA is miscible with Ph‐PLAs and that the attractive interaction between PDLA and L‐configured Ph‐PLA is higher than that between PDLA and D‐configured Ph‐PDLA. In other words, the latter result means that poly(lactic acid) (PLA) has a higher stereoselective attractive interaction with Ph‐PLA with the reverse configuration than with Ph‐PLA of the same configuration. These results strongly suggest that PLA‐based materials with a wide variety of physical properties and biodegradability can be fabricated by blending them with substituted PLAs with the reverse and same configurations.magnified image
Association of ERCC1 polymorphisms and susceptibility to nasopharyngeal carcinoma
Authors: Yang Zhi‐Hui , Dai Qiong , Kong Xiang‐Li , Yang Wen‐Li , Zhang Lin 
Published: July 2008

AbstractThe normal function of excision repair cross complementing group 1 (ERCC1) is essential for maintaining genomic integrity and preventing cellular neoplastic transformation, and multiple studies have reported an association between ERCC1 polymorphisms and increased risk of cancers. To test whether the genetic variants of ERCC1 gene modify the risk of nasopharyngeal carcinoma (NPC), we compared the 8092 C > A and 19007 C > T single nucleotide polymorphisms (SNPs) and the haplotypes of ERCC1 between 267 patients with NPC and 304 healthy controls. Linkage disequilibrium was observed between the two SNPs loci (D′ = 0.861). Significant differences of allele frequencies were found for ERCC1 8092C > A between the cases and controls. Individuals with 8092 C allele showed 1.411‐fold (OR = 1.411, 95% CI, 1.076–1.850, P = 0.014) increased risk of developing NPC, and the CC haplotype was associated with a significantly increased risk of NPC (OR = 1.712; 95% CI, 1.211–2.421; P = 0.013). No interactions were found between 8092C > A polymorphism and genders, smoking status and alcohol consumption. These results suggested that the polymorphism of ERCC1 8092 C > A might be a contributing factor in the development of NPC in Chinese population. © 2008 Wiley‐Liss, Inc.
Could a perfect model ever satisfy a naïve forecaster? On grid box mean versus point verification
Authors: Göber Martin , Zsótér Ervin , Richardson David S. 
Published: July 2008

AbstractNumerical models forecast grid box means, whereas forecasters have to deliver point forecasts, often in the form of ‘the most severe weather possible in a small area’. There can be substantial differences between areal means and point values, depending on the subgrid‐scale variability. Forecasters are generally well aware of subgrid‐scale variability when making local predictions of severe events. However, in evaluating the model this is often left out of consideration.An experiment was performed to estimate the effect of ‘imperfectly verifying’ grid box means against point observations. A ‘perfect model’ was constructed by taking the grid box average of high‐density observations of daily precipitation amount, but the verification of this ‘perfect’ forecast is far from being accurate. The model deviation from the observations is minimal for small precipitation amounts, and becomes larger as more severe events are to be forecast. The error solely due to the wrong kind of verification is of the order of the forecast error itself.If one has to verify against point observations, the baseline to compare numerical models against is not the theoretical best score value but the score achieved by the “perfect model”. Thus, this study underlines again the imperative to compare numerical models against upscaled observation.Even a perfect model could not nearly satisfy a naïve forecaster who just wants to pass a model value to a customer in need of a point forecast. Good forecasters apply some post‐processing in order to estimate the subgrid‐scale variability and thus the probability of exceeding some threshold. Copyright © 2008 Royal Meteorological Society
Biliary fibrosis in microsurgical extrahepatic cholestasis in the rat
Authors: Sánchez‐Patán Fernando , Anchuelo Raquel , Corcuera María‐Teresa , Casado Isabel , Gómez‐Aguado Fernando , Aller María‐Angeles , Cruz Arturo , Alonso María‐José , Arias Jaime 
Published: July 2008

AbstractA new model of extrahepatic cholestasis, using a microsurgical technique, is performed as an alternative to the traditional model of the bile duct ligated‐rat, in order to study the stage of fibrosis in the long‐term. Male Wistar rats were divided into two groups: I (Sham‐operated, n = 9) and II [Microsurgical Cholestasis (MC), n = 10]. After 4 weeks, portal pressure, types of portosystemic collateral circulation, mesenteric venous vasculopathy, hepatic function test, and liver histopathology were studied by using the Knodell index and fibrosis was determined by reticulin and Sirius red stains. The animals with MC presented portal hypertension with extrahepatic portosistemic collateral circulation, associated with mesenteric venous vasculopathy and increased plasma levels of bilirubin (6.30 ± 1.80 vs. 0.22 ± 0.37 mg/dL; P = 0.0001), alkaline phosphatase (293.00 ± 82.40 vs. 126.30 ± 33.42 U/L; P = 0.001), AST (380.00 ± 78.50 vs. 68.33 ± 11.74 IU/L; P = 0.0001), ALT (87.60 ± 22.32 vs. 42.22 ± 7.89 IU/L; P = 0.0001), and LDH (697.76 ± 75.13 vs. 384.80 ± 100.03 IU/L; P = 0.0001). On the contrary, plasma levels of albumin decreased (2.72 ± 0.12 mg/dl vs. 2.99 ± 0.10; P = 0.001). The microsurgical resection of the extrahepatic biliary tract in the rat produces an experimental model of hepatic inflammation, characterized by a high Knodell hepatic activity index (4), bile proliferation, and fibrosis. © 2008 Wiley‐Liss, Inc. Microsurgery, 2008.
Minimum free energy for an electromagnetic conductor with memory
Authors: Amendola G. , Fabrizio M. , Golden J. M. 
Published: July 2008

AbstractA closed expression is determined in the frequency domain for the minimum free energy associated with a state of a linear electromagnetic conductor with memory effects, using the fact that this quantity is equal to the maximum recoverable work obtainable from the given state of the material. Another equivalent expression is also derived and applied to evaluate explicit formulae for a discrete spectrum model. In particular, for such a model we present the results corresponding to only one inverse time decay for each of the three kernels of the constitutive equations. These results clearly show the effects of various parameters on the expression for the minimum free energy. Copyright © 2008 John Wiley & Sons, Ltd.
Linear instability of ideal flows on a sphere
Authors: Skiba Yuri N. 
Published: July 2008

AbstractA unified approach to the normal mode instability study of steady solutions to the vorticity equation governing the motion of an ideal incompressible fluid on a rotating sphere is considered. The four types of well‐known solutions are considered, namely, the Legendre‐polynomial (LP) flows, Rossby–Haurwitz (RH) waves, Wu–Verkley (WV) waves and modons. A conservation law for disturbances to each solution is derived and used to obtain a necessary condition for its exponential instability. By these conditions, Fjörtoft's (Tellus 1953; 5:225–230) average spectral number of the amplitude of an unstable mode must be equal to a special value. In the case of LP flows or RH waves, this value is related only with the basic flow degree. For the WV waves and modons, it depends both on the basic flow degree and on the spectral distribution of the mode energy in the inner and outer regions of the flow. Peculiarities of the instability conditions for different types of modons are discussed. The new instability conditions specify the spectral structure of growing disturbances localizing them in the phase space. For the LP flows, this condition complements the well‐known Rayleigh–Kuo and Fjörtoft conditions related to the zonal flow profile. Some analytical and numerical examples are considered. The maximum growth rate of unstable modes is also estimated, and the orthogonality of any unstable, decaying and non‐stationary mode to the basic flow is shown in the energy inner product.The analytical instability results obtained here can also be applied for testing the accuracy of computational programs and algorithms used for the numerical stability study. It should be stressed that Fjörtoft's spectral number appearing both in the instability conditions and in the maximum growth rate estimates is the parameter of paramount importance in the linear instability problem of ideal flows on a sphere. Copyright © 2008 John Wiley & Sons, Ltd.
Continuous dependence results for a class of nonlinear heat equations in a cylindrical region
Authors: Philippin G. A. , Proytcheva V. , Vernier‐Piro S. 
Published: July 2008

AbstractIn this paper, we derive bounds for the solutions of a quasilinear heat equation in a finite cylindrical region if the far end and the lateral surface are held at zero temperature, and a nonzero temperature is applied at the near end. Some continuous dependence inequalities are also obtained. We also investigate the case in which a given heat flux is prescribed at the near end, instead of a given temperature. Copyright © 2008 John Wiley & Sons, Ltd.
Formal verification of tail distribution bounds in the HOL theorem prover
Authors: Hasan Osman , Tahar Sofiène 
Published: July 2008

AbstractTail distribution bounds play a major role in the estimation of failure probabilities in performance and reliability analysis of systems. They are usually estimated using Markov's and Chebyshev's inequalities, which represent tail distribution bounds for a random variable in terms of its mean or variance. This paper presents the formal verification of Markov's and Chebyshev's inequalities for discrete random variables using a higher‐order‐logic theorem prover. The paper also provides the formal verification of mean and variance relations for some of the widely used discrete random variables, such as Uniform(m), Bernoulli(p), Geometric(p) and Binomial(m, p) random variables. This infrastructure allows us to precisely reason about the tail distribution properties and thus turns out to be quite useful for the analysis of systems used in safety‐critical domains, such as space, medicine or transportation. For illustration purposes, we present the performance analysis of the coupon collector's problem, a well‐known commercially used algorithm. Copyright © 2008 John Wiley & Sons, Ltd.
Special power series expansions of monogenic functions around surfaces of codimension two
Authors: Peña Peña Dixan , Sommen Frank 
Published: July 2008

AbstractIn this paper we will focus on power series expansions around special surfaces of codimension two, in particular around spheres and products of spheres. This will include a version of the Cauchy–Kowalewski extension theorem around these surfaces. This higher codimension result was only obtained so far in the flat case (see Partial Differential Equations with Complex Analysis. Pitman Research Notes Mathematical Series, vol. 262. Longman Science and Technology: Harlow, 1992; 61–92; Mathematics and its Applications, vol. 53. Kluwer Academic Publishers Group: Dordrecht, 1992). Copyright © 2008 John Wiley & Sons, Ltd.
Hodge–Helmholtz decompositions of weighted Sobolev spaces in irregular exterior domains with inhomogeneous and anisotropic media
Authors: Pauly Dirk 
Published: July 2008

AbstractWe study in detail Hodge–Helmholtz decompositions in nonsmooth exterior domains Ω⊂ℝN filled with inhomogeneous and anisotropic media. We show decompositions of alternating differential forms of rank q belonging to the weighted L2‐space Ls2, q(Ω), s∈ℝ, into irrotational and solenoidal q‐forms. These decompositions are essential tools, for example, in electro‐magnetic theory for exterior domains. To the best of our knowledge, these decompositions in exterior domains with nonsmooth boundaries and inhomogeneous and anisotropic media are fully new results. In the Appendix, we translate our results to the classical framework of vector analysis N=3 and q=1, 2. Copyright © 2008 John Wiley & Sons, Ltd.
Global solvability for a large flux of a three‐dimensional time‐dependent Navier–Stokes problem in a straight cylinder
Authors: Pileckas K. , Zaja̧czkowski W. 
Published: July 2008

AbstractThe unique global existence of a solution to nonstationary Navier–Stokes system with prescribed nonzero flux F(t) in an infinite three‐dimensional pipe is proved. The obtained solution remains close to the corresponding nonstationary Poiseuille flow. Moreover, it converges to the Poiseuille flow as |x3|→∞. Copyright © 2008 John Wiley & Sons, Ltd.
Influence of relative configuration of disubstituted cyclopentanes and ‐hexanes on 13C shifts
Authors: Winkler Margit , Klempier Norbert , Weber Hansjörg , Grünwald Katrin R. , Flock Michaela , Dransfeld Alk 
Published: July 2008

Abstract13C shifts of disubstituted cyclopentane and cyclohexane derivatives were compared in dependence on the relative configuration of the two substituents. A diequatorial substitution correlates with deshielding compared to other substitution patterns. Some novel fluorinated cyclopentanes and ‐hexanes including their DFT calculation‐assisted structure elucidation are described. Copyright © 2008 John Wiley & Sons, Ltd.
Structural and spectral assignments of six anthraquinone derivatives from the mangrove fungus (ZSUH‐36)
Authors: Shao Changlun , Wang Changyun , Wei Meiyan , Li Shangde , She Zhigang , Gu Yucheng , Lin Yongcheng 
Published: July 2008

AbstractA new natural product named 6,8,1′‐tri‐O‐methyl averantin(1) has been isolated together with five known anthraquinones 1′‐O‐methyl averantin(2), 6,8‐di‐O‐methyl averufin (3) averufin (4), versicolorin C (5) and 6,8‐di‐O‐methyl averufanin (6) from a mangrove endophytic fungus ZSUH‐36 collected from the South China Sea. NMR techniques including COSY, HMQC, and HMBC were used to elucidate the structures of these compounds. We report the unambiguous assignments of the 1H and 13C NMR spectra of the new compound 6,8,1′‐tri‐O‐methyl averantin(1). Copyright © 2008 John Wiley & Sons, Ltd.
Complete basis set B3LYP NMR calculations of CDCl3 solvent's water fine spectral details
Authors: Kupka Teobald 
Published: July 2008

AbstractThe assignment of singlet at 1.55 ppm and the 1:1:1 triplet at 1.519 ppm to H2O and HOD in the 400 MHz 1H NMR spectrum of CDCl3 solvent were supported by complete basis set (CBS) GIAO‐B3LYP calculated chemical shift and the CBS B3LYP estimated 2J(D,H) spin–spin coupling constant (SSCC). The CBS fitting of B3LYP/cc‐pCVxZ and B3LYP/pcJ‐n predicted SSCC values, the accurate value of 2J(D,H) = − 1.082 ± 0.030 Hz of HOD in chloroform‐d1 and the H/D isotopic shift of 0.0307(1) ppm were reported for the first time. The agreement between CBS B3LYP predicted chemical shift, spin–spin values and experiment was good. Copyright © 2008 John Wiley & Sons, Ltd.
Simultaneous Controllability of PSD and MWD in Emulsion Polymerisation
Authors: Sweetman Stephen J. , Immanuel Charles D. , Malik Tahir I. , Emmett Simon , Williams Neal 
Published: July 2008

AbstractA sensitivity study of particle size distribution (PSD) and molecular weight distribution (MWD) responses to perturbations in initiator, surfactant, monomer and chain transfer agent in a semi‐batch emulsion polymerisation is presented. The objective is to provide a systematic study on the ability to simultaneously control both PSD and MWD, towards inferential control of end‐use product properties. This would lead towards identification of the practical feasible regions of operability. All inputs appeared to have an intrinsic and simultaneous influence on end‐time PSD and MWD. Trends shown in experimental results have been explained in a mechanistic sense and also compared to simulation results from a combined PSD/MWD population balance model. The preliminary comparison between experiment and simulation highlights areas to be focussed on with respect to model improvement.magnified image
Investigation of Catalytic Chain Transfer Copolymerization of Methacrylates
Authors: Nikitin Anatoly N. , Grady Michael C. , Kalfas Georgios A. , Hutchinson Robin A. 
Published: July 2008

AbstractBatch experiments were carried out to investigate the kinetics of catalytic chain transfer copolymerization of methyl methacrylate and n‐butyl methacrylate. The Predici® model developed to represent the system describes the numerous experimental data measured at high concentrations of Co(II) catalyst, taking into account the chain‐length dependencies of termination, propagation and catalytic chain transfer. The constants for catalytic chain transfer are determined as 2.3 × 104 for both methyl methacrylate and n‐butyl methacrylate from fitting the experimental data. Two inhibition mechanisms are shown to describe the decrease of the polymerization rate in the presence of catalyst equally well, with an unknown impurity dissolved in initiator introduced to explain experimental profiles measured at high initiator concentrations.magnified image