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81.
This article reports on the synthesis, characterization, and properties of various anthracene‐containing poly (p‐phenylene‐ethynylene)‐alt‐poly(p‐phenylene‐vinylene) (PPE‐PPV) polymers (AnE‐PVs) bearing statistical distributions of various side chains. Primarily, the ratio of linear octyloxy and branched 2‐ethylhexyloxy side chains at the poly(p‐phenylene vinylene) (PPV) parts was varied, leading to the polymers stat, stat1, and stat2. Furthermore, polymers also containing asymmetric substituted PPV and poly(p‐phenylene ethynylene) units (bearing methoxy and 2‐ethylhexyloxy side chains) were prepared yielding stat3, stat4, and stat5. These materials exhibit a broad variation in their photovoltaic properties. It is once more shown that side chains and their distribution can crucially affect the photovoltaic device performance. The introduction of units with asymmetric substitution into these systems seems to be harmful for their utilization in photovoltaic applications. Organic field‐effect transistors were fabricated to investigate hole mobilities in these new materials. Large variance was observed, falling in the range of almost two orders of magnitude, indicating rather different π–π stacking behavior of the polymer backbones owing to side‐chain modifications. Moreover, a selection of the new polymeric systems was investigated regarding their potential for light‐emitting diode (LED) applications. Polymer LEDs using the polymers AnE‐PVstat, ‐stat3, ‐stat4, and ‐stat5, as the active layer showed turn‐on voltage of ~2 V and exhibited red light emission. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012  相似文献   
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Here we report the monitoring the instant creation of a new fluorescent signal (FS) aroused from a positively charged water-soluble fluorogenic probe, ethidium bromide (EtBr) in the presence of a radical initiator, ammonium persulfate (APS) and an accelerator, tetraethylmetilendiamine (TEMED) for evaluation of deoxyribonucleic acid (DNA) conformation. The results revealed that the occurred FS (λex?=?430 nm; λmax?=?525 nm) is a reduced form of EtBr (λex?=?480 nm; λmax?=?617 nm) and it is completely distinct from hydroethidine (λex?=?350 nm; λmax?=?430 nm), which is two-electron reduced form of EtBr. It was noticed that EtBr was reduced to a new FS during the polymerization of N, N dimethyacrylamide (DMAA) too, at 25 °C in the presence of APS and TEMED or at 55 °C with only APS, and the rate of formation of FS was increased upon treatment time. The effect of nanoclays such as Laponite XLG® and Laponite XLS®, which provide a protective environment for DNA in nature, were also investigated through the reduction process of EtBr in the absence and presence of a water soluble monomer DMAA. We demonstrated that DNA conformation might be evaluated by monitoring FS effectuated during the reduction of EtBr in the presence of nanoclays having positively and negatively charged surfaces. Protective property of DNA against the formation of reduced product was elucidated by carrying out the polymerization at 55 °C. The results revealed that the monitoring of formation of FS in the presence of radical initiator could lead to elucidate the conformation of DNA upon formation of intercalator complex.  相似文献   
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In this study, we investigate an adaptive decomposition and ordering strategy that automatically divides examinations into difficult and easy sets for constructing an examination timetable. The examinations in the difficult set are considered to be hard to place and hence are listed before the ones in the easy set in the construction process. Moreover, the examinations within each set are ordered using different strategies based on graph colouring heuristics. Initially, the examinations are placed into the easy set. During the construction process, examinations that cannot be scheduled are identified as the ones causing infeasibility and are moved forward in the difficult set to ensure earlier assignment in subsequent attempts. On the other hand, the examinations that can be scheduled remain in the easy set. Within the easy set, a new subset called the boundary set is introduced to accommodate shuffling strategies to change the given ordering of examinations. The proposed approach, which incorporates different ordering and shuffling strategies, is explored on the Carter benchmark problems. The empirical results show that the performance of our algorithm is broadly comparable to existing constructive approaches.  相似文献   
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The energy profile of a frustrated Lewis pair (FLP) dihydrogen splitting system was determined by a combined experimental kinetic and DFT study. A trimethylene‐bridged phosphane–borane FLP was converted into its endothermic H2‐cleavage product by sequential H+/H? addition. The system could be handled at low temperature, and the kinetics of the H2 elimination were determined to give a rate constant of kHH,exp(299 K)=(2.87±0.1)×10?4 s?1 in solution. The primary kinetic isotope effects were determined; for example, (kHH/kDD)exp=3.19. The system was accurately analyzed by DFT calculations.  相似文献   
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Ukrainian Mathematical Journal - The method of Green’s functional is a little-known technique for the construction of fundamental solutions to linear ordinary differential equations (ODE)...  相似文献   
90.
Öneş  O.  Alkan  M. 《Ukrainian Mathematical Journal》2020,71(9):1419-1428
Ukrainian Mathematical Journal - We determine some classes of left modules satisfying the radical formula in a noncommutative ring. We also show that, under a certain condition, a finitely...  相似文献   
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