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71.
Tetraarylthiophenes were prepared by regioselective Suzuki cross-coupling reactions of tetrabromothiophene. 相似文献
72.
A Bio‐inspired Cu4O4 Cubane: Effective Molecular Catalysts for Electrocatalytic Water Oxidation in Aqueous Solution 下载免费PDF全文
Xin Jiang Jian Li Bing Yang Xiang‐Zhu Wei Bo‐Wei Dong Yi Kao Mao‐Yong Huang Prof. Chen‐Ho Tung Prof. Li‐Zhu Wu 《Angewandte Chemie (International ed. in English)》2018,57(26):7850-7854
Inspired by the cubic Mn4CaO5 cluster of natural oxygen‐evolving complex in Photosystem II, tetrametallic molecular water oxidation catalysts, especially M4O4 cubane‐like clusters (M=transition metals), have aroused great interest in developing highly active and robust catalysts for water oxidation. Among these M4O4 clusters, however, copper‐based molecular catalysts are poorly understood. Now, bio‐inspired Cu4O4 cubanes are presented as effective molecular catalysts for electrocatalytic water oxidation in aqueous solution (pH 12). The exceptional catalytic activity is manifested with a turnover frequency (TOF) of 267 s?1 for [(LGly‐Cu)4] at 1.70 V and 105 s?1 for [(LGlu‐Cu)4] at 1.56 V. Electrochemical and spectroscopic study revealed a successive two‐electron transfer process in the Cu4O4 cubanes to form high‐valent CuIII and CuIIIO. intermediates during the catalysis. 相似文献
73.
Le Tuan Anh A. T. Soldatenkov Zh. A. Mamyrbekova S. A. Soldatova K. B. Polyanskiy Tran Thanh Tung V. N. Khrustalev 《Chemistry of Heterocyclic Compounds》2008,44(11):1404-1412
4,8a-Diphenyl-substituted 2-(2-propoxy)perhydro[1,3,2]dioxaborinino[5.4-c]pyridine was obtained by the condensation of 4-hydroxy-3-(α-hydroxybenzyl)-1-methyl-4-phenylpiperidine
with triisopropyl borate, and its 2-hydroxysubstituted analog in the presence of water. 1-Methyl-4,8a-diphenyl-perhidro[1,3]dioxano[5,4-c]pyridine
was synthesized by the reaction of the same piperidol with formaldehyde. A comparative study of the molecular structures of
the three products was carried out by X-ray crystallography.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, 1726–1735, November, 2008. 相似文献
74.
High Performance Nonvolatile Transistor Memories Utilizing Functional Polyimide‐Based Supramolecular Electrets 下载免费PDF全文
Wei‐Yao Tung Meng‐Hsien Li Dr. Hung‐Chin Wu Hsin‐Yu Liu Yun‐Ting Hsieh Prof. Wen‐Chang Chen 《化学:亚洲杂志》2016,11(10):1631-1640
We report pentacene‐based organic field‐effect transistor memory devices utilizing supramolecular electrets, consisting of a polyimide, PI(6FOH‐ODPA), containing hydroxyl groups for hydrogen bonding with amine functionalized aromatic rings (AM) of 1‐aniline (AM1), 2‐naphthylamine (AM2), 2‐aminoanthracene (AM3), and 1‐aminopyrene (AM4). The effect of the phenyl ring size and composition of AM1–AM4 on the hole‐trapping capability of the fabricated devices was investigated systematically. Under an operating voltage under ±40 V, the prepared devices using the electrets of 100 % AM1–AM4/PI ratios exhibited a memory window of 0, 8.59, 25.97, and 29.95 V, respectively, suggesting that the hole‐trapping capability increased with enhancing phenyl ring size. The memory window was enhanced as the amount of AM in PI increased. Furthermore, the devices showed a long charge‐retention time of 104 s with an ON/OFF current ratio of around 103–104 and multiple switching stability over 100 cycles. This study demonstrated that the electrical characteristics of the OFET memory devices could be manipulated through the chemical compositions of the supramolecular electrets. 相似文献
75.
Antibacterial poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) fibrous membranes containing quaternary ammonium salts 下载免费PDF全文
Xiaoyan Fan Maoli Yin Zhiming Jiang Nengyu Pan Xuehong Ren Tung‐Shi Huang 《先进技术聚合物》2016,27(12):1617-1624
In this study, antimicrobial membranes based on biodegradable material poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) [P(3HB‐4HB)] and quaternary ammonium salts (QASs) by two methods have been performed. Three QASs with varied alkyl chain lengths have been synthesized successfully and characterized by 1H nuclear magnetic resonance and Fourier transform infrared. The synthesized QASs were blended with P(3HB‐4HB) and electrospun into composite fibrous membranes or casted into conventional membranes. Electrospun fibrous membranes with large surface areas are a superior type of antimicrobial biomaterials, and they exhibit preferable properties than solution casting membranes. Specifically, electrospun fibrous membranes are tougher and can inactivate both Gram‐positive Staphylococcus aureus and Gram‐negative Escherichia coli O157:H7 in a contact time of 30 min, whereas the solution casting membranes cannot. The length of alkyl chain in the quaternary ammonium groups on the modified P(3HB‐4HB) membranes is able to influence the antimicrobial activity. This type of antimicrobial material may have potential applications in biomaterial field. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
76.
Parton distribution functions consistent with neutrino and muon deep inelastic scattering as well as Drell-Yan pair production results have been extracted. This analysis incorporates experimental systematic errors which are the dominant errors in recent deep inelastic scattering experiments. The dependence of the results on factors such as kinematic cuts in the data, heavy target corrections, and choice of initial functional form are also explored. The form adopted is motivated by perturbative QCD and particularly useful in exploring the small-x extrapolation of the distributions. This is crucial for studying the range of predictions for Collider, HERA, and SSC/LHC cross sections. Representative distribution function sets are presented in a very compact parametrized form both in the DIS and MS-bar renormalization schemes.This work is partially supported by the National Science Foundation under Grant No. PHY89-05161. This work was also supported by Argonne National Laboratory during the 1988–89 academic year when the author was on Sabbatical leave at the Laboratory from IIT 相似文献
77.
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79.
L. H. Tung 《Journal of Polymer Science.Polymer Physics》1969,7(1):47-55
A method of determining the distribution of branching in polydisperse polymer samples is proposed. This method uses data from concurrent gel permeation chromatography and sedimentation-velocity experiments. Tedious fractionation, which must precede other methods of determining long-chain branching, is eliminated. An example of use of the method on the data of a sample of styrene–divinylbenzene copolymer is given. 相似文献
80.
The Nachtmann moments of deep inelastic scattering structure functions are required by kinematics to contain a so far neglected threshold factor which is dependent on both n and q2. Its presence significantly affects the “moment analysis” in the usual QCD phenomenology and it resolves the difficulties connected with improper threshold behavior of the “ξ-scaling” analysis of structure functions. 相似文献