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251.
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Constantinos G. Screttas Georgios A. Heropoulos Maria Micha-Screttas Barry R. Steele 《Tetrahedron letters》2005,46(25):4357-4360
Diethyl ether is a convenient solvent for the reductive lithiation of allylic phenyl thioethers without the serious complications, which occur when the reaction is carried out in tetrahydrofuran. 相似文献
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Vasiliadou IA Papoulis D Chrysikopoulos CV Panagiotaras D Karakosta E Fardis M Papavassiliou G 《Colloids and surfaces. B, Biointerfaces》2011,84(2):354-359
The attachment of Pseudomonas (P.) putida onto well (KGa-1) and poorly (KGa-2) crystallized kaolinite was investigated in this study. Batch experiments were carried out to determine the attachment isotherms of P. putida onto both types of kaolinite particles. The attachment process of P. putida onto KGa-1 and KGa-2 was adequately described by a Langmuir isotherm. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance were employed to study the attachment mechanisms of P. putida. Experimental results indicated that KGa-2 presented higher affinity and attachment capacity than KGa-1. It was shown that electrostatic interactions and clay mineral structural disorders can influence the attachment capacity of clay mineral particles. 相似文献
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Panagiota N. Eleni Magdalini K. KrokidaGregory L. Polyzois Constantinos A. CharitidisElias P. Koumoulos Vasiliki P. TsikourkitoudiIoannis Ziomas 《Polymer Degradation and Stability》2011,96(4):470-476
The degradation of maxillofacial prosthetic elastomers that occur during physical weathering is usually responsible for the replacement of the prosthesis. In this study the mechanical behaviour of a polydimethylsiloxane (PDMS) elastomer was investigated, after 1 year outdoor weathering in two different weathering locations in Greece (Thessaloniki, Athens). The hypothesis investigated was that irradiation time did not affect the measured properties. Specimens (Elastomer 42) were prepared according to manufacturer’s instructions and exposed to solar radiation for 1 year. Compression, tensile and nanoindentation tests were performed before and after the exposure. Compression and tensile data were also subjected to analysis of variance (ANOVA) and Tukey Post hoc tests at a level of α = .05. These properties were selected due to their clinical significance for fabrication and maintenance of a facial prosthesis. According to statistical analysis all the measured properties changed significantly after outdoor weathering. More specifically, most of the properties presented significant changes after six months of weathering. The observed changes also depended on the weathering locations. The hypothesis investigated was rejected. Material A became harder and the observed differences in the mechanical behaviour resulted from photo-degradation and hydrolysis that might occur due to weathering. The study also provides new information about maxillofacial prosthetics serviceability obtained from nanoindentation tests. 相似文献
257.
Mosquito flight tones occur during locomotion and courtship and are mostly analyzed using microphones. The use of microphones is impractical for analyzing the wingbeat of non-tethered insects especially if one is interested in studying the frequency content of wingbeats of a large number of insects. In this study we present a practical setting based on a novel 2D optical sensor that we embed inside insectary cages to record the wingbeats of three mosquito species belonging to three different genera, namely Culex pipiens molestus, Anopheles gambiae and Aedes albopictus. We show that this setting allows to automatically create distributions of parameters related to wingbeat frequency and harmonic properties derived from many non-tethered wingbeats and therefore characterize the wingbeat properties of a whole species with increased confidence. Implications for potential applications are discussed. 相似文献
258.
Michail E. Kavousanakis Lucia Russo Francesco Saverio Marra Constantinos Siettos 《Combustion Theory and Modelling》2013,17(1):40-52
We analyse the dynamics of a model describing a planar diffusion flame with radiative heat losses incorporating a single step kinetic using timestepping techniques for Lewis number equal to one. We construct the full bifurcation diagram with respect to the Damköhler number including the branches of oscillating solutions. Based on this analysis we found, for the first time, homoclinic bifurcations that mark the abrupt disappearance of the nonlinear oscillations near extinction as reported in experiments. 相似文献
259.
Electromagnetic attenuation effect within a short distance can be very useful in numerous devices and occasions. It is exploited for experimental (anechoic chambers in laboratories), military (anti-radar coatings of aircrafts and ships) and computational (realization of absorbing boundary conditions in software simulations) reasons. In this work, we compare the attenuation inflicted by a hyperbolic metamaterial with that occurred into an ordinary lossy dielectric. In order for the comparison to be fair, we use the same magnitude of permittivity and the same loss tangent in both cases; similarly, the reflection coefficient is kept low in all the regarded examples. The results indicate that the hyperbolic metamaterial vastly outperforms the commonly used dielectric and one can use these media in order to construct very thin and efficient attenuators or absorbers by considering moderate thermal losses. 相似文献
260.
Analytical derivatization either in pre or post column modes is one of the most widely used sample pretreatment techniques coupled to liquid chromatography. In the present review article we selected to discuss the post column derivatization mode for the analysis of organic compounds. The first part of the review focuses to the instrumentation of post-column setups including not only fundamental components such as pumps and reactors but also less common parts such as static mixers and back-pressure regulators; the second part of the article discusses the most popular “chemistries” that are involved in post column applications, including reagent-less approaches and new sensing platforms such as the popular gold nanoparticles. Some representative recent applications are also presented as tables. 相似文献