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排序方式: 共有311条查询结果,搜索用时 15 毫秒
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Baik JM Shon Y Lee SJ Jeong YH Kang TW Lee JL 《Journal of the American Chemical Society》2008,130(41):13522-13523
We report the room-temperature ferromagnetism in transition metals (Co, Ni)-doped 8-hydroxy-quinoline aluminum (Alq3) by thermal coevaporation of high purity metal and Alq3 powders. For 5% Co-doped Alq3, a maximum magnetization of approximately 0.33 microB/Co at 10 K was obtained and ferromagnetic behavior was observed up to 300 K. The Co atoms interact chemically with O atoms and provide electrons to Alq3, forming new states acting as electron trap sites. From this, it is suggested that ferromagnetism may be associated with the strong chemical interaction of Co atoms and Alq3 molecules. 相似文献
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Chanho Pak Seung Woo Lee Chaekyung Baik Bong Ho Lee Dae Jong You Eunyoung You 《中国化学快报》2019,30(6):1186-1189
New approach for the reversal tolerant anode for polymer electrolyte membrane fuel cell is suggested by using the multifunctional IrRu alloy catalyst having concurrent superior activities towards hydrogen oxidation reaction and oxygen evolution reaction to mitigate the degradation of anode under the fuel starvation condition. 相似文献
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Dr. Todor Baramov Bianca Schmid Ho Ryu Jinhoon Jeong Dr. Karlijn Keijzer Dr. Leonard von Eckardstein Prof. Dr. Mu-Hyun Baik Prof. Dr. Roderich D. Süssmuth 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(28):6955-6962
The E. coli siderophore enterobactin, the strongest FeIII chelator known to date, forms hexacoordinate complexes with SiIV, GeIV, and TiIV. Synthetic protocols have been developed to prepare non-symmetric enterobactin analogues with varying denticities. Various benzoic acid residues were coupled to the macrocyclic lactone to afford a diverse library of ligands. These enterobactin analogues were bound to SiIV, GeIV, and TiIV, and the complexes were investigated through experimental and computational techniques. The binding behavior of the synthesized chelators enabled assessment of the contribution of each of the phenolic hydroxy groups in enterobactin to metal-ion complexation. It was found that at least four O-donors are needed for enterobactin derivatives to act as metal binders. Density functional theory calculations indicate that the strong binding behavior of enterobactin can be ascribed to a diminished translational entropy penalty, a common feature of the chelate effect, coupled with the structural arrangement of the three catechol moieties, which allows the triseryl base to be installed without distorting the preferred local metal-binding geometry of the catecholate ligands. 相似文献
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M. H. Baik W. J. Cho P. S. Hahn 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(3):495-502
Surface sorption experiments of U(VI) onto the surfaces of a Korean granite rock are carried out in order to investigate the
kinetics and reversibility of U(VI) sorption as a function of pH and surface types such as fresh intact surfaces and natural
fracture surfaces. It was shown that the effect of pH is significant in the sorption of U(VI) onto both types of the granite
surfaces. However the sorption rates do not greatly depend upon the pH regardless of the surface types. A two-step first order
kinetic behavior dominates onto both the intact surfaces and natural fracture surfaces of granite and that the linearization
approach of the kinetic model agrees well with experimental sorption data. The desorption results showed that the sorption
process of U(VI) was a little irreversible for the two types of granite surfaces regardless of pH and surface types. This
kinetic approach could give a better understanding of U(VI) sorption onto granite surfaces depending on pH and surface types.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Se Hoon Ki Somin Sin Jae-Ho Shin Young Wan Kwon Myoung Won Chae Han Sup Uhm Ku Youn Baik Eun Ha Choi 《Plasma Chemistry and Plasma Processing》2018,38(5):937-952
The studies with proteins are necessary to understand the biological effects of atmospheric pressure plasma (APP). Among proteins, those with transient metal ions play key roles in many biological events and they are very sensitive to environmental redox states. Iron-containing hemoglobin (Hb) is investigated in this study, after APP treatments under two environmental gas conditions of pure N2 and N2?+?O2 mixture. Monitoring the intensity change for absorption spectra could lead to a quantitative assessment of the effect of discharge plasma on Hb. Redox states of Hb are classified into five states including O2-bound Hb (oxy-Hb), deoxy-Hb, met-Hb, NO-bound Hb (NO-Hb), and hemichrome. Chemically generated reactive species and some scavengers are applied to understand the chemical reactions. Our experimental results confirm the complex chemical reactions of APP and suggest the possible use of Hb as a model protein for the visualization of APP biological effects. 相似文献
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Hoimin Jung Mannkyu Hong Marianna Marchini Marco Villa Philipp S. Steinlandt Xiaoqiang Huang Marcel Hemming Eric Meggers Paola Ceroni Jiyong Park Mu-Hyun Baik 《Chemical science》2021,12(28):9673
The mechanism of [2 + 2] cycloadditions activated by visible light and catalyzed by bis-cyclometalated Rh(iii) and Ir(iii) photocatalysts was investigated, combining density functional theory calculations and spectroscopic techniques. Experimental observations show that the Rh-based photocatalyst produces excellent yield and enantioselectivity whereas the Ir-photocatalyst yields racemates. Two different mechanistic features were found to compete with each other, namely the direct photoactivation of the catalyst–substrate complex and outer-sphere triplet energy transfer. Our integrated analysis suggests that the direct photocatalysis is the inner working of the Rh-catalyzed reaction, whereas the Ir catalyst serves as a triplet sensitizer that activates cycloaddition via an outer-sphere triplet excited state energy transfer mechanism.The mechanism of [2 + 2] cycloadditions activated by visible light and catalyzed by bis-cyclometalated Rh(iii) and Ir(iii) photocatalysts was investigated, combining density functional theory calculations and spectroscopic techniques. 相似文献
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Byeong Hyo Kim Rongbi HanFengyu Piao Young Moo JunWoonphil Baik Byung Min Lee 《Tetrahedron letters》2003,44(1):77-79
N-Arylacetamides were prepared in excellent yields from nitroarenes in the presence of acetic anhydride, acetic acid and indium by a one-pot procedure. 相似文献