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761.
Kyung Moon Jung Kyung Hwan Kim Jung‐Il Jin Min Ju Cho Dong Hoon Choi 《Journal of polymer science. Part A, Polymer chemistry》2008,46(22):7517-7533
New deep‐red light‐emitting phosphorescent dendrimers with hole‐transporting carbazole dendrons were synthesized by reacting tris(2‐benzo[b]thiophen‐2‐yl‐pyridyl) iridium (III) complex with carbazolyl dendrons by DCC‐catalyzed esterification. The resulting first‐, second‐, and third‐generation dendrimers were found to be highly efficient as solution‐processable emitting materials and for use in host‐free electrophosphorescent light‐emitting diodes. We fabricated a host‐free dendrimer EL device with configuration ITO/PEDOT:PSS (40 nm)/dendrimer (55 nm)/BCP (10 nm)/Alq3 (40 nm)/LiF (1 nm)/Al (100 nm) and characterized the device performance. The multilayered devices showed luminance of 561 cd/m2 at 383.4 mA/cm2 (12 V) for 15 , 1302 cd/m2 at 321.3 mA/cm2 (14 V) for 16 , and 422 cd/m2 at 94.4 mA/cm2 (18 V) for 17 . The third‐generation dendrimer, 17 (ηext = 6.12% at 7.5 V), showed the highest external quantum efficiency (EQE) with an increase in the density of the light‐harvesting carbazole dendron. Three dendrimers exhibited considerably pure deep‐red emission with CIE 1931 (Commission International de L'Eclairage) chromaticity coordinates of x = 0.70, y = 0.30. The CIE coordinates remained very stable with the current density. The integration of rigid hole‐transporting dendrons and phosphorescent complexes provides a new route to design highly efficient solution‐processable materials for dendrimer light‐emitting diode (DLED) applications. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7517–7533, 2008 相似文献
762.
We report the first total synthesis of glycyrol. Glycyrol, isolated from Glycyrrhizae Radix, has a unique skeleton of a benzofuran coumarin. The key steps are Smiles rearrangement and selective introduction of prenyl and O-methyl groups. The first application of a novel precursor for Smiles rearrangement, 3-benzyloxy-substituted (diacetoxyiodo)benzene, showed the synthetic possibility for diverse precursors. The introduction of a benzyl protecting group was important because selective deprotection was hard due to the low solubility of intermediates. 相似文献
763.
764.
765.
A recyclable gold catalyst is synthesized from readily available reagents by immobilizing gold nanoparticles in aluminum oxyhydroxide support through a simple sol-gel method. The catalyst showed the high activity even at room temperature in the aerobic oxidation of various alcohols and in the coupling reaction between primary alcohols and ketones. 相似文献
766.
Sung Hwan Hwang Mu Hee Cho Sae-Kyoung Kang Han Seo Cho Tae-Woo Lee Hyo-Hoon Park 《Lightwave Technology, Journal of》2008,26(11):1479-1485
An architecture of a passively assembled optical platform is suggested for a chip-to-chip optical interconnection system. The platform is constructed using all-fiber media for the optical paths: a fiber-embedded optical printed-circuit board (OPCB) and 90-bent fiber connector. The passive assembling was achieved by employing the guide pins/holes of commercialized ferrules in the optical link between the OPCB, 90-bent fiber connector, and the transmitter/receiver (Tx/Rx) module. From this interconnection scheme, a low total optical loss of was obtained. From an assembled platform with 10 Gb/s/ch 4 ch Tx/Rx modules, a 7-Gb/s/ch data transmission was demonstrated with a bit error rate below , involving the optical and electrical crosstalk arisen in the whole channel operation. 相似文献
767.
Heinrich W. E. Jung 《Mathematische Zeitschrift》1922,14(1):1-34
Ohne Zusammenfassung 相似文献
768.
In this paper, the question posed in the title is critically examined on the basis of the available literature evidence implying the positive answer. The distinction between, on the one hand, the actual crystal field (CF) or equivalently ligand field (LF) related quantities and, on the other hand, the actual zero-field splitting (ZFS) or equivalently fine structure (FS) quantities, is elucidated. The origin and possible roots of the incorrect terminology consisting in mixing up the two physically distinct quantities at different levels are examined. Aspects concerning Hamiltonians, parameters, energy level splitting, and nature of the operators involved are taken into account. Problems with the various notations for the operators and parameters used in the electron magnetic resonance (EMR) area are also identified and reviewed. A large number of cases of incorrect terminology and other inconsistencies identified in the course of a comprehensive literature survey are analyzed and systematically classified. Implications of the confusion in question, which go beyond the simple semantic issues, are discussed. The results of the survey reveal that the two most serious categories of this confusion lead to misinterpretation of the experimental EMR data. Several examples of serious misinterpretations found in the books, reviews, and original papers are discussed. The incorrect terminology contributes also to misleading keyword classifications of papers in journals as well as references in scientific literature databases. Thus, the database searches may produce unreliable outcomes. Examples of such outcomes are also shown. It is concluded that, in order to prevent further proliferation of the incorrect terminology and thus to increase reliability of the published EMR data, a concerted effort within the EMR community is indispensable. Various ways in this regard at the international level are suggested. 相似文献
769.
770.