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61.
In this Letter we investigate the error performance of multiple-input multiple-output free-space optical communication systems employing intensity modulation/direct detection and operating over strong atmospheric turbulence channels. Atmospheric-induced strong turbulence fading is modeled using the negative exponential distribution. For the considered system, an approximate yet accurate analytical expression for the average bit error probability is derived and an efficient method for its numerical evaluation is proposed. Numerically evaluated and computer simulation results are further provided to demonstrate the validity of the proposed mathematical analysis. 相似文献
62.
George Z. Kyzas Eleni A. Deliyanni Kostas A. Matis Nikolaos K. Lazaridis Dimitrios N. Bikiaris Athanasios C. Mitropoulos 《Composite Interfaces》2018,25(5-7):415-454
AbstractBiomedicine and pharmacy identify highly important scientific fields within the present time. However, increased advancements in these sciences have influenced the identification of increased levels in environmental degradation through pollution. Pharmaceutical production has influenced increased scientific and public concern regarding the increasing rate of pollution attributed to high levels of toxicological properties within the products. Pharmaceutical compounds are not fully removed through the integration of wastewater treatment plants (WWTP). This renders pharmaceutical compounds, municipal effluents together with hospitals as the major culprits in the development of the majority of the sources that enhance environmental degradation. A wide range of the compounds have been the identified within WWTP effluents, surface water together with ground and drinking water on a global scale. All above has influenced the research development in technological field developing new ways for efficient removal of pharmaceuticals from wastewater produced from the pharmaceuticals or biomedical industries. This situation may be altered through the utilization of adsorbents. Therefore more studies have been published investigating the use of nanocomposite biomaterials for removing the pharmaceutical compounds existing in biomedical effluents. 相似文献
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65.
Back Cover: Corrole and Porphyrin Amino Acid Conjugates: Synthesis and Physicochemical Properties (Chem. Eur. J. 32/2016) 下载免费PDF全文
Kostas Karikis Evangelos Georgilis Georgios Charalambidis Athanasia Petrou Dr. Olena Vakuliuk Theodore Chatziioannou Iliana Raptaki Sofia Tsovola Ioanna Papakyriacou Prof. Anna Mitraki Prof. Daniel T. Gryko Prof. Athanassios G. Coutsolelos 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(32):11472-11472
66.
Peter Wick Anna E. Louw‐Gaume Melanie Kucki Harald F. Krug Kostas Kostarelos Bengt Fadeel Kenneth A. Dawson Anna Salvati Ester Vzquez Laura Ballerini Mauro Tretiach Fabio Benfenati Emmanuel Flahaut Laury Gauthier Maurizio Prato Alberto Bianco 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(30):7846-7850
67.
Evangelia Xenogiannopoulou Miroslav Medved Kostas Iliopoulos Stelios Couris Manthos G Papadopoulos Davide Bonifazi Chloè Sooambar Aurelio Mateo-Alonso Maurizio Prato 《Chemphyschem》2007,8(7):1056-1064
A series of novel [60]fullerene-ferrocene and [60]fullerene-porphyrin dyads, in which a fullerene and an electron donating moiety are attached through a flexible triethylene glycol linker are synthesized and their nonlinear optical (NLO) response studied. Specifically, the third-order susceptibility chi(3) of all fullerene derivatives are measured in toluene solutions by the optical Kerr effect (OKE) technique using 532 nm, 35 ps laser pulses and their second hyperpolarizability gamma are determined. All fullerene dyads studied exhibit enhancement of their NLO response compared to pristine fullerenes which has been attributed to the formation of a charge separated state. All experimentally measured hyperpolarizability gamma values are also calculated by the semiempirical methods AM1 and PM3. A good correlation is found between the theoretical and experimental values, suggesting that simple semiempirical methods can be employed for the designing and optimization of the fullerene-containing dyads displaying improved nonlinear responses. 相似文献
68.
A palladium complex with a new hemilabile amino- and sulfur-containing phosphinite ligand has been synthesised and its crystal structure determined. This system efficiently catalyses the Heck reaction of aryl bromides with styrene at 130°C after 24 h, with turnover numbers of up to 100000 and with a selectivity towards trans-stilbenes ranging from 91.5 to 96.3%. The analogous sulfur-containing phosphinite without the amino group has also been synthesised and subjected to the Heck reaction. The constructive role of the amino group on the formation of the P,S-chelate palladium complex as well as in the Heck reaction is discussed. 相似文献
69.
o-Quinone methides are formed from the reaction of nucleophiles with trimethylsilyl(methyl)-1,4-benzoquinones. These reactive intermediates are trapped by excess nucleophile to form substituted quinones following oxidation. In addition, varying amounts of a symmetrical dimer and a xanthen derivative were observed. The influence of different nucleophiles and ring substituents on the rate of reaction have been studied, and are consistent with rate-limiting formation of a vinylogous enolate initiated by attack of the nucleophile on the silyl group. 相似文献
70.
Chandrasena RE Vatsis KP Coon MJ Hollenberg PF Newcomb M 《Journal of the American Chemical Society》2004,126(1):115-126
Intramolecular and intermolecular kinetic isotope effects (KIEs) were determined for hydroxylation of the enantiomers of trans-2-(p-trifluoromethylphenyl)cyclopropylmethane (1) by hepatic cytochrome P450 enzymes, P450s 2B1, Delta2B4, Delta2B4 T302A, Delta2E1, and Delta2E1 T303A. Two products from oxidation of the methyl group were obtained, unrearranged trans-2-(p-trifluoromethylphenyl)cyclopropylmethanol (2) and rearranged 1-(p-trifluoromethylphenyl)but-3-en-1-ol (3). In intramolecular KIE studies with dideuteriomethyl substrates (1-d(2)) and in intermolecular KIE studies with mixtures of undeuterated (1-d(0)) and trideuteriomethyl (1-d(3)) substrates, the apparent KIE for product 2 was consistently larger than the apparent KIE for product 3 by a factor of ca. 1.2. Large intramolecular KIEs found with 1-d(2) (k(H)/k(D) = 9-11 at 10 degrees C) were shown not to be complicated by tunneling effects by variable temperature studies with two P450 enzymes. The results require two independent isotope-sensitive processes in the overall hydroxylation reactions that are either competitive or sequential. Intermolecular KIEs were partially masked in all cases and largely masked for some P450s. The intra- and intermolecular KIE results were combined to determine the relative rate constants for the unmasking and hydroxylation reactions, and a qualitative correlation was found for the unmasking reaction and release of hydrogen peroxide from four of the P450 enzymes in the absence of substrate. The results are consistent with the two-oxidants model for P450 (Vaz, A. D. N.; McGinnity, D. F.; Coon, M. J. Proc. Natl. Acad. Sci. U.S.A. 1998, 95, 3555), which postulates that a hydroperoxy-iron species (or a protonated analogue of this species) is a viable electrophilic oxidant in addition to the consensus oxidant, iron-oxo. 相似文献