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221.
Joarder B Chaudhari AK Rogez G Ghosh SK 《Dalton transactions (Cambridge, England : 2003)》2012,41(25):7695-7699
Herein, we present a carboxylate-based dinuclear dysprosium compound, namely [Dy(2)L(6)(MeOH)(2)(H(2)O)(2)] (LH = n-butyric acid) from the reaction of Dy(NO(3))(3)·xH(2)O with n-butyric acid and triethylamine in MeOH solvent. The single crystal X-ray diffraction analysis demonstrate that a total of six monocarboxylate ligands formed this dimeric compound by carboxylate bridging along with coordination from solvent molecules (water and methanol). Each Dy(III) ion is coordinated by nine donor atoms forming a mono-capped antiprismatic coordination environment. Alternating current (AC) magnetic measurements show a frequency dependence of the out-of-phase magnetic susceptibilities (χ') indicating a slow relaxation behaviour of the magnetization. 相似文献
222.
Using density functional theory calculations, we investigated the structural, energetic, electronic, and optical properties of recently synthesized duplex DNA containing metal‐mediated base pairs. The studied duplex DNA consists of three imidazole (Im) units linked through metal (Im‐M‐Im, M=metal) and four flanking A:T base pairs (two on each side). We examined the role of artificial base pairing in the presence of two distinctive metal ions, diamagnetic Ag+ and magnetic Cu2+ ions, on the stability of duplex DNA. We found that metal‐mediated base pairs form stable duplex DNA by direct metal ion coordination to the Im bases. Our results suggest a higher binding stability of base pairing mediated by Cu2+ ions than by Ag+ ions, which is attributed to a larger extent of orbital hybridization. We furthermore found that DNA modified with Im‐Ag+‐Im shows the low‐energy optical absorption characteristic of π–π*orbital transition of WC A:T base pairs. On the other hand, we found that the low‐energy optical absorption peaks for DNA modified with Im‐Cu2+‐Im originate from spin–spin interactions. Additionally, this complex exhibits weak ferromagnetic coupling between Cu2+ ions and strong spin polarization, which could be used for memory devices. Moreover, analyzing the role of counter ions (Na+) and the presence of explicit water molecules on the structural stability and electronic properties of the DNA duplex modified with Im‐Ag+‐Im, we found that the impact of these two factors is negligible. Our results are fruitful for understanding the experimental data and suggest a potential route for constructing effective metal‐mediated base pairs in duplex DNA for optoelectronic applications. 相似文献
223.
Functionalization of edge reconstructed graphene nanoribbons by H and Fe: A density functional study
Soumyajyoti Haldar Sumanta Bhandary Satadeep Bhattacharjee Olle Eriksson Dilip Kanhere Biplab Sanyal 《Solid State Communications》2012,152(18):1719-1724
In this paper, we have studied functionalization of 5–7 edge-reconstructed graphene nanoribbons by ab initio density functional calculations. Our studies show that hydrogenation at the reconstructed edges is favorable in contrast to the case of unreconstructed 6–6 zigzag edges, in agreement with previous theoretical results. Thermodynamical calculations reveal the relative stability of single and dihydrogenated edges under different temperatures and chemical potential of hydrogen gas. From phonon calculations, we find that the lowest optical phonon modes are hardened due to 5–7 edge reconstruction compared to the 6–6 unreconstructed hydrogenated edges. Finally, edge functionalization by Fe atoms reveals a dimerized Fe chain structure along the edges. The magnetic exchange coupling across the edges varies between ferromagnetic and antiferromagnetic ones with the variation of the width of the nanoribbons. 相似文献
224.
225.
A new thermoreversible hydrogel of riboflavin and melamine supramolecular complex (> or =0.02%, w/v) shows enhanced photoluminescence properties through H-bonding. 相似文献
226.
The effects of dissipative dynamics on the magnitude of entanglement generated In atom-photon interactions inside cavities
is studied. We present some concrete examples of environment Induced entanglement in alom-photon interactions. We consider
various dissipative atom-cavity systems and show that their collective dynamics can be used to maximize entanglement for intermediate
values of the cavity leakage parameter κ. We first consider the interaction of a single two-level atom with one of two coupled
microwave cavities and show analytically that the atom-cavity entanglement increases with cavity leakage. We next consider
a system of two atoms passing successively through a cavity and derive the expression for the maximum value of in terms of
the Rabi angle gt, for which the two-atom entanglement can be Increased. Finally, numerical investigation of micromaser dynamics also reveals
the increase of two-atom entanglement with stronger cavity-environment coupling for experimentally attainable values of the
micromaser parameters. 相似文献
227.
Subhasis Mallick Subala Mondal Biplab K. Bera Parnajyoti Karmakar Sankar C. Moi Alak K. Ghosh 《Transition Metal Chemistry》2010,35(4):469-475
The kinetics of the interaction between thiourea and the title complex has been studied spectrophotometrically in aqueous
medium as a function of nucleophile concentration, temperature and pH at constant ionic strength. The reaction is a two-step
process in which the first step is ligand dependent, but the second step is ligand independent and is assigned to ring closure.
The rate and activation parameters, conductivity studies and IR data were used to deduce a plausible mechanism. 相似文献
228.
Xia Gao Ruigang Liu Yin Yu Manna Jin Haishan Bu 《Journal of Polymer Science.Polymer Physics》2004,42(2):296-301
The influence of additives on the crystal modification and melting behavior of poly(ethylene‐2,6‐naphthalene dicarboxylate) (PEN) was investigated with wide‐angle X‐ray diffraction and differential scanning calorimetry (DSC). The addition of a nucleating promoter, Ceraflour 993, had no effect on the crystal modification and melting behavior of PEN crystallized under all chosen experimental conditions. However, the addition of a nucleating agent, sodium benzoate (SB), did affect the crystal modification and melting behavior of PEN when PEN/SB was crystallized at a higher temperature, but not at a lower temperature. A mixture of α and β modifications of PEN was obtained, and an overlapped dual melting peak was observed in DSC curves when PEN was crystallized at a higher temperature in the presence of SB, instead of a single crystal form and a single melting peak for the crystallization of pure PEN. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 296–301, 2004 相似文献
229.
The present paper discusses the application of large eddy simulation to incompressible turbulent flows in complex geometries. Algorithmic developments concerning the flow solver were provided in the companion paper (Int. J. Numer. Meth. Fluids, 2003; submitted), which addressed the development and validation of a multi‐domain kernel suitable for the integration of the elliptic partial differential equations arising from the fractional step procedure applied to the incompressible Navier–Stokes equations. Numerical results for several test problems are compared to reference experimental and numerical data to demonstrate the potential of the method. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
230.
Giampaolo Barone Marina Cotta Ramusino Renato Barbieri Gianfranco La Manna 《Journal of Molecular Structure》1999,469(1-3):143-149
The interaction between a dinucleotide triphosphate duplex (DD), mimicking the DNA molecule, and the dimethyltin(IV) cation is studied by the semiempirical PM3 method. The results show that the interaction can occur involving the tin atom and the electron-donor centres of DD, requiring in some cases the presence of water molecules. In particular, the binding of the dimethyltin(IV) moiety with two adjacent phosphate oxygen atoms is allowed by the presence of water molecules coordinating to the tin atom. In this case the tin environment shows a geometry in agreement with 119Sn Mössbauer and X-ray data. 相似文献