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991.
In this work, we propose cooperative metaheuristic methods for the permutation flowshop scheduling problem considering two objectives separately: total tardiness and makespan. We use the island model where each island runs an instance of the algorithm and communications start when the islands have reached certain level of evolution, that is, communication is not allowed from the beginning of the execution. Subsequent ones occur when new better solutions are found. We carry out an exhaustive comparison of the cooperative methods against the sequential counterparts running in completely comparable scenarios. Results have been carefully analysed by means of statistical procedures and we can conclude that the cooperative methods yield much better results than the sequential algorithms and state-of-the-art methods running in the same number of processors but without communications. The proposed cooperative schemes are easy to apply to other algorithms and problems. 相似文献
992.
Teresa García-Valderrama Eva Mulero-MendigorriDaniel Revuelta-Bordoy 《European Journal of Operational Research》2009
The objective of this article is to propose a framework for analysis of the relationships between the four perspectives of the balanced scorecard (BSC) of Kaplan and Norton. To this end, several different models of efficiency have been developed, utilising data envelopment analysis (DEA). Each of the variables has been extracted from a model of the BSC for research and development (R&D) activities. A study has been carried out with 90 companies to illustrate a case of this analysis. 相似文献
993.
Markus Himmelsbach Wolfgang Buchberger Eva Reingruber 《Polymer Degradation and Stability》2009,94(8):1213-1219
A method for the determination of polymer additives like antioxidants, UV absorbers and processing stabilizers using liquid chromatography (LC) coupled with atmospheric pressure photoionization mass spectrometry (APPI-MS) is presented. Ion source parameters were optimized regarding temperatures, gas flow rates, and voltages applied. Detection limits were determined using APPI with or without dopant and were compared with electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). Differences between APPI, ESI and APCI are pointed out and the effect of the dopant toluene and acetone is discussed. The optimized method yielded detection limits between 0.001 mg L−1 and 0.022 mg L−1 for 15 different analytes. Linear calibration plots could be obtained for all solutes over a wide concentration range showing satisfying repeatability with standard deviations of peak areas between 3.4% and 7.6%. The results indicate that the developed method can be regarded as suitable for the quantitative determination of polymer additives even at low concentration levels. 相似文献
994.
In the past decade, more than 100 different cathinone derivatives slopped over entire Europe due to their enormous popularity. Generally, these novel psychoactive substances are easily available via the internet. This fact leads to various social problems, since cathinones are substances with consciousness‐changing effects and are mainly misused for recreational matters by their consumers. Cathinones possess a chiral center including two enantiomeric forms with potentially different pharmacological behavior. This fact makes analytical method development regarding their chiral separation indispensable. In this study, a chiral capillary zone electrophoresis method for the enantioseparation of 61 cathinone and pyrovalerone derivatives was developed by means of four different β‐cyclodextrin derivatives. As chiral selectors, native β‐cyclodextrin as well as three of its derivatives namely acetyl‐β‐cyclodextrin, 2‐hydroxypropyl‐β‐cyclodextrin, and carboxymethyl‐β‐cyclodextrin were used. The cathinone and pyrovalerone derivatives were either purchased in internet stores or seized by police. As a result, overall 58 of 61 studied substances were partially or baseline separated by at least one of the four chiral selectors using 10 mM of β‐cyclodextrin derivative in a 10 mM sodium phosphate buffer (pH 2.5). Furthermore, the method was found to be suitable for simultaneous enantioseparations, for enantiomeric purity checks and to differentiate between positional isomers. Moreover, an intra‐ and an interday validation was performed successfully for each chiral selector to prove the robustness of the method. 相似文献
995.
Bartlomiej?Sojka Aurelia?Liskova Miroslava?Kuricova Mateusz?Banski Jan?Misiewicz Maria?Dusinska Mira?Horvathova Silvia?Ilavska Michaela?Szabova Eva?Rollerova Artur?PodhorodeckiEmail author Jana?TulinskaEmail author 《Journal of nanoparticle research》2017,19(2):68
Sodium fluoride-based β-NaLnF4 nanoparticles (NPs) doped with lanthanide ions are promising materials for application as luminescent markers in bio-imaging. In this work, the effect of NPs doped with yttrium (Y), gadolinium (Gd), europium (Eu), thulium (Tm), ytterbium (Yb) and terbium (Tb) ions on phagocytic activity of monocytes and granulocytes and the respiratory burst was examined. The surface functionalization of <10-nm NPs was performed according to our variation of patent pending ligand exchange method that resulted in meso-2,3-dimercaptosuccinic acid (DMSA) molecules on their surface. Y-core-based NCs were doped with Eu ions, which enabled them to be excited with UV light wavelengths. Cultures of human peripheral blood (n = 8) were in vitro treated with five different concentrations of eight NPs for 24 h. In summary, neither type of nanoparticles is found toxic with respect to conducted test; however, some cause toxic effects (they have statistically significant deviations compared to reference) in some selected doses tested. Both core types of NPs (Y-core and Gd-core) impaired the phagocytic activity of monocytes the strongest, having minimal or none whatsoever influence on granulocytes and respiratory burst of phagocytic cells. The lowest toxicity was observed in Gd-core, Yb, Tm dopants and near-infrared nanoparticles. Clear dose-dependent effect of NPs on phagocytic activity of leukocytes and respiratory burst of cells was observed for limited number of samples. 相似文献
996.
A method for solving geodesic equations in Schwarzschild–de Sitter space–times and higher dimensional Schwarzschild space–times is presented. The solutions are derived from Jacobi's inversion problem on a Riemann surface of genus 2 restricted to the set of zeros of the theta function, which is called a theta–divisor. In its final form, the solutions are given in terms of derivatives of Kleinian sigma functions. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
997.
Emma Rossinyol Eva Pellicer Anna Prim Sònia Estradé Jordi Arbiol Francesca Peiró Albert Cornet Joan Ramon Morante 《Journal of nanoparticle research》2008,10(2):369-375
Highly crystalline and thermally stable gadolinium doped ceria (GDC) particles have been synthesized by hard template route
for the first time. This oxide is being recognized as an intermediate temperature (500–700 °C) electrolyte material for applications
in solid-oxide fuel cells. The GDC particles show high crystallinity and nanometric size (2.83 ± 0.05 nm in diameter) and
Raman analyses confirm the formation of the solid solution instead of a CeO2 and Gd2O3 mixture. EDX and EELS studies indicate a stoichiometry coherent with the Gd0.2Ce0.8O1.9 phase. The synthesized nanometric powder is expected to be used in solid oxide fuel cells as well as in the catalytic treatment
of automobile exhaust fumes.
Graphical abstract相似文献
998.
Eva Millqvist Mats Bende Moa Brynnel Inger Johansson Sofi Kappel Ann-Christine Ohlsson 《Journal of voice》2008,22(4):512-515
Voice problems are seldom reported in pollen allergy, although the allergic reaction involves the entire airways. The objective of this study was to investigate voice dysfunction during the pollen season in patients with allergic rhinitis. Thirty patients with verified birch pollen allergy and 30 controls were investigated twice, during the pollen season and outside the pollen season. Both times they scored respiratory and voice symptoms, the latter with the validated questionnaire Voice Handicap Index (VHI), and performed standardized voice recordings. These recordings were analyzed in a controlled manner by a professional voice therapist. During the allergy season, patients reported more respiratory and voice symptoms compared with controls. Those with blinded scored voice dysfunction scored their voice quality during springtime as 31 mm (95% confidence interval [CI] 20-42 mm), compared with 13 mm (95% CI 6-21 mm for participants without voice dysfunction (P<0.01). Furthermore, the group with experienced voice dysfunction scored significantly higher on the VHI in the functional and physical domains and in the total VHI score. Although voice problems during the pollen season are rarely discussed, in allergic rhinitis the larynx may also be involved. These findings support that some patients experience voice change, an experience which can be objectively confirmed. 相似文献
999.
1000.