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41.
Graphene oxide (GO) particles in aqueous dispersions can form liquid crystal (LC) phases at extremely low concentrations due to the extremely high aspect ratio of the flakes and noticeably, they possess an extremely large Kerr coefficient attractive for low power consumption electro‐optic devices. Reduced graphene does not easily form LC phases in water due to its hydrophobic nature but here we show that stable dispersions of reduced graphene oxide can be realized with surfactants and that they exhibit birefringence upon shearing as well as under application of electric fields. The performance of the system is largely superior to GO LC possessing longer time stability and drastically improved electro‐optic properties with an induced birefringence twice as large at the same field strength thanks to the almost recovery of graphene properties upon reduction. (© 2016 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim) 相似文献
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Youn Jeong Jang Dr. Jae Young Kim Won Yong Kim Prof. Jeong Kon Seo Prof. Sungjee Kim Prof. Kun‐Hong Lee Prof. Jae Sung Lee 《Angewandte Chemie (International ed. in English)》2014,53(23):5852-5857
As a photocathode for CO2 reduction, zinc‐blende zinc telluride (ZnTe) was directly formed on a Zn/ZnO nanowire substrate by a simple dissolution–recrystallization mechanism without any surfactant. With the most negative conduction‐band edge among p‐type semiconductors, this new photocatalyst showed efficient and stable CO formation in photoelectrochemical CO2 reduction at ?0.2–?0.7 V versus RHE without a sacrificial reagent. 相似文献
44.
Hye Mi Oh Ji Eun Park Jisu Kim Ju Hyun Kim Prof. Youn K. Kang Prof. Young Keun Chung 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(29):9024-9036
A method for the synthesis of bicyclo[4.1.0]heptenes from 1,6‐enynes through Pd‐catalyzed cycloisomerization has been developed. N‐ and O‐tethered 1,6‐enynes were successfully transformed to their corresponding 3‐aza‐ and 3‐oxabicyclo[4.1.0]heptenes in reasonable‐to‐high yields using the catalysts [PdCl2(CH3CN)2]/P(OPh)3 or [Pd(maleimidate)2(PPh3)2] in toluene. The computational calculations using density functional theory indicate that [PdCl2{P(OPh)3}] in the oxidation state PdII acts as the active catalyst species for the formation of 3‐azabicyclo[4.1.0]heptenes through 6‐endo‐dig cyclization. 相似文献
45.
Denise T. B. De Salvi Hernane S. Barud Agnieszka Pawlicka Ritamara I. Mattos Ellen Raphael Younés Messaddeq Sidney J. L. Ribeiro 《Cellulose (London, England)》2014,21(3):1975-1985
New bacterial cellulose (BC)–triethanolamine (TEA) ion-conducting membranes have been prepared and characterized. The samples were obtained by soaking BC membranes in triethanolamine aqueous solutions and drying. The scanning electron microscopy pictures revealed that the incorporation of TEA in BC membranes covers the cellulose microfibrils. Raman spectra exhibited BC and TEA characteristic group frequencies and thermal analysis evidenced an influence of TEA content on the sample thermal stability. The ion-conductivity as a function of the temperature showed an Arrhenius behavior increasing from 1.8 × 10?5 S/cm at room temperature to 7.0 × 10?4 S/cm at 80 °C for the BC–TEA 1 M sample. 相似文献
46.
Luminous Butterflies: Efficient Exciton Harvesting by Benzophenone Derivatives for Full‐Color Delayed Fluorescence OLEDs
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Sae Youn Lee Prof. Dr. Takuma Yasuda Dr. Yu Seok Yang Dr. Qisheng Zhang Prof. Dr. Chihaya Adachi 《Angewandte Chemie (International ed. in English)》2014,53(25):6402-6406
Butterfly‐shaped luminescent benzophenone derivatives with small energy gaps between their singlet and triplet excited states are used to achieve efficient full‐color delayed fluorescence. Organic light‐emitting diodes (OLEDs) with these benzophenone derivatives doped in the emissive layer can generate electroluminescence ranging from blue to orange–red and white, with maximum external quantum efficiencies of up to 14.3 %. Triplet excitons are efficiently harvested through delayed fluorescence channels. 相似文献
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[reaction: see text] Asymmetric diol boronic esters with potassium bifluoride form the corresponding alkyltrifluoroborate and free diol under mild conditions. Defluoridation with tetrachlorosilane produces an alkyldifluoroborane intermediate. This conversion of relatively unreactive boronic esters to derivatives that are strong Lewis acids opens new synthetic opportunities, as illustrated by the preparation of (R)-2-phenylpyrrolidine in 98% ee from a pinanediol or 1,2-dicyclohexyl-1,2-ethanediol boronic ester via potassium (2-phenyl-4-azidobutyl)trifluoroborate. 相似文献
49.
On the basis of a pyrrolidine tweezer 1, a library of peptidosulfonamide tweezers (15a-e, 16a-e) was synthesized on the solid phase. This library was screened in a simultaneous substrate screening procedure for the ability to enantioselectively catalyze the Ti(O-i-Pr)(4)-mediated addition of diethylzinc to aldehydes. One of the best solid-phase tweezer catalyst (i.e., 16d, giving an ee of 32% in solid-phase catalysis) was resynthesized in solution (compounds 20 and 21). The now homogeneous solution-phase catalysis showed even better enantioselectivity (i.e., up to 66%). 相似文献
50.
Pressure reducing valves are widely used to maintain the pressure of gas reservoirs to specific values. In a normal valve,
supply pressure is decompressed with an orifice structure. When compressed air passes through the orifice structure, considerable
noise occurs at the downstream side. In this paper, we have developed a radial slit structure that can reduce pressure without
noise. The noise is reduced by changing the orifice structure into the radial slit structure. The radial slit structure valve
reduces pressure without noise by suppressing the generation of turbulence and shock wave at the downstream. The analysis
of the flow in radial slit structure was achieved by CFD2000 software. The flow rate and pressure distribution were simulated
and compared with the experimental result. To confirm the generation of shock wave, the flow of orifice and radial slit structure
at the downstream was visualized by Schlieren photography method. A shock wave was generated in the orifice structure, but
no shock wave was generated in the radial slit structure. Noise reduction efficiency was investigated by the experiment. The
experiment apparatus was set up to JIS standards. The experimental results indicated that the noise level decreased by approximately
40 dB in the slit structure. It is confirmed that the radial slit structure has effectiveness for low noise in the pressure
reducing flow. And, it is expected that it can be applied to various kinds of industrial fields. 相似文献