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991.
Ling‐Hai Xie Xian‐Yu Deng Lin Chen Shu‐Fen Chen Ran‐Ran Liu Xiao‐Ya Hou King‐Young Wong Qi‐Dan Ling Wei Huang 《Journal of polymer science. Part A, Polymer chemistry》2009,47(20):5221-5229
The combination of π‐stacked with π‐conjugated building blocks offers an essential strategy to construct multifunctional organic semiconductors (MOSs) with the unique optoelectrical properties. Covalent hybrids can efficiently avoid the intrinsic phase‐separation defects in corresponding blend system. In this contribution, poly(vinylcarbazole) tethered with terfluorene, PVK‐TF, as a double‐channeled π‐stacked and π‐conjugated hybrid (SCH), has been constructed via Friedal‐Crafts click postmodification (FCCP). The chemical structure and optoelectrical property were determined by GPC, UV–vis, PL, TGA, DSC, and CV. Its PL spectra in the annealing thin film at N2 atmosphere without low‐energy emission bands centered at the 530 nm indicates that no π‐stacks between carbazole and TF or among TFs dominate the whole condensed phase, which is in agreement with the intrachain T‐shaped π‐pitched motifs in molecular modeling simulation due to steric hindrance effect in complicated diarylfluorenes (CDAFs). A supporting prototype stable deep‐blue PLED was successfully obtained with an Internationale de l'Eclairage (CIE) coordinates of (0.20, 0.10) and a width at half maximum (FWHM) of about 60 nm at high current density of 100 mA/cm2 (35 V). Deep‐blue PVK‐TF is a promising MOS for hole‐transporting and host materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5221–5229, 2009 相似文献
992.
Ga‐Young Lee Jin‐Hyang Kim Hyo Jin No Ju‐Yeon Lee Bum Ku Rhee Hee‐dok Choi 《Journal of polymer science. Part A, Polymer chemistry》2009,47(7):1911-1919
1‐{3,4‐Di‐(2‐hydroxyethoxy)phenyl}‐2‐(2‐thiophenyl)ethene (5) was prepared and condensed with terephthaloyl chloride to yield polyester (6). Polymer 6 was reacted with tetracyanoethylene to give a new Y‐type polyester (7) containing 1‐(3,4‐dioxyethoxy)phenyl‐2‐{5‐(2,2,3‐tricyanovinyl)‐2‐thiophenyl)}ethenyl groups as NLO‐chromophores, which are components of the polymer backbones. Polyester 7 is soluble in common organic solvents such as N,N‐dimethylformamide and acetone. Polymer 7 showed a thermal stability up to 300 °C in thermogravimetric analysis with glass transition temperature (Tg) obtained from differential scanning calorimetry near 126 °C. The second harmonic generation (SHG) coefficient (d33) of poled polymer film at the 1560 nm fundamental wavelength was around 6.57 × 10?9 esu. The dipole alignment exhibited high thermal stability up to the Tg, and there was no SHG decay below 125 °C due to the partial main‐chain character of polymer structure, which is acceptable for NLO device applications. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1911–1919, 2009 相似文献
993.
Soon Hyung Kang Moon-Sung Kang Sang-Hyun Choi Jae-Yup Kim Hyun-Sik Kim Taeghwan Hyeon Yung-Eun Sung 《Electrochemistry communications》2008,10(9):1326-1329
Dye-sensitized solar cells (DSSCs) employing a viscous non-volatile electrolyte were prepared by utilizing anatase TiO2 nanorods (synthesized via oriented attachment) as a photoanode material. One promising way to enhance the photovoltaic performance of DSSCs employing viscous electrolytes is to increase ion conductivity by increasing the salt concentration. This is accompanied by an acceleration of the charge recombination reaction and the limiting of the overall conversion efficiency. The results showed that a TiO2 nanorod electrode enables more favorable electron transport than a conventional nanoparticle-based electrode due to the improved electron diffusion length and the large intrinsic surface area. 相似文献
994.
Feasibility routes for thermal plasma production of silicon nitride powders are explored. First, a collation of the various proposed systems from the extant literature is examined. Reactant systems investigated include free silicon, silicon monoxide, silicon dioxide, silicon tetrachloride, silane, and other organosilicon precursors, along with various nitriding and reducing species. The reaction yields of these systems are brought to a common denominator by thermodynamic analysis and a first-step introduction of nucleation kinetics including comparisons against published experiments and the authors' own research. In particular, it is observed that the formation of liquid-phase free silicon in the neighborhood of 2500 K is quite detrimental to silicon nitride yield, and furthermore, a high supersaturation of silicon should always be avoided. 相似文献
995.
Quantised phase filters with binary low and high pass amplitude response: the effect of quantisation for scale and rotation input distortions 总被引:1,自引:0,他引:1
Triantafillos Koukoulas Rupert C.D. Young Chris R. Chatwin 《Optics and Lasers in Engineering》2005,43(9):963
In the field of optical pattern recognition, there are a large number of filters that possess identification capabilities for certain kinds of input distortions. The resolution of the spectral components plays an important role in the overall processing time of a correlator that may employ such filters. In this paper, two different techniques are discussed: low pass phase filtering and high pass phase filtering. This is achieved by binarizing the amplitude information which then allows certain frequencies to pass and others to be blocked. Their response to different kinds of input distortions is presented and the effect of phase quantisation is considered in detail. 相似文献
996.
997.
A straightforward and efficient method has been developed for the synthesis of α‐aminonitriles by combining aldehydes, amines and trimethylsilyl cyanide in the presence of a catalytic amount of thallium(III) chloride tetrahydrate (1 mol%) under solvent‐free conditions at room temperature. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
998.
Ah Yeon Park So‐Young Park Jaehyun Lee Mihye Jung Jinwoong Kim Sam Sik Kang Jeong‐Rok Youm Sang Beom Han 《Biomedical chromatography : BMC》2009,23(10):1034-1043
Rapid, simple and reliable HPLC/UV and LC‐ESI‐MS/MS methods for the simultaneous determination of five active coumarins of Angelicae dahuricae Radix, byakangelicol (1), oxypeucedanin (2), imperatorin (3), phellopterin (4) and isoimperatorin (5) were developed and validated. The separation condition for HPLC/UV was optimized using a Develosil RPAQUEOUS C30 column using 70% acetonitrile in water as the mobile phase. This HPLC/UV method was successful for providing the baseline separation of the five coumarins with no interfering peaks detected in the 70% ethanol extract of Angelicae dahuricae Radix. The specific determination of the five coumarins was also accomplished by a triple quadrupole tandem mass spectrometer equipped with an electrospray ionization source (LC‐ESI‐MS/MS). Multiple reaction monitoring (MRM) in the positive mode was used to enhance the selectivity of detection. The LC‐ESI‐MS/MS methods were successfully applied for the determination of the five major coumarins in Angelicae dahuricae Radix. These HPLC/UV and LC‐ESI‐MS/MS methods were validated in terms of recovery, linearity, accuracy and precision (intra‐ and inter‐day validation). Taken together, the shorter analysis time involved makes these HPLC/UV and LC‐ESI‐MS/MS methods valuable for the commercial quality control of Angelicae dahuricae Radix extracts and its pharmaceutical preparations. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
999.
M. Farsari S. Huang R. C. D. Young M. I. Heywood C. D. Bradfield C. R. Chatwin 《Optics and Lasers in Engineering》1999,31(3):10
The optical characteristics of a commercial UV curable resin are investigated using non-degenerate four-wave mixing. The material assessed is an epoxy resin, DuPont SomosTM 7100. The holographic gratings were written at a wavelength of λ=351.1 nm for an irradiance range 0.5–3.0 W/cm2 and read at λ=632.8 nm in order to assess the reactivity, curing speed, shrinkage and resolution of the resin. 相似文献
1000.