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131.
Electrical conduction is well understood in materials formed from inorganic or organic building blocks, but their combination to produce conductive hybrid frameworks and networks is an emerging and rapidly developing field of research. Self-assembling organic-inorganic compounds offer immense potential for functionalising material properties for a wide scope of applications including solar cells, light emitters, gas sensors and bipolar transparent conductors. The flexibility of combining two distinct material classes into a single solid-state system provides an almost infinite number of chemical and structural possibilities; however, there is currently no systematic approach established for designing new compositions and configurations with targeted electronic or optical properties. We review the current status in the field, in particular, the range of hybrid systems reported to date and the important role of materials modelling in the field. From theoretical arguments, the Mott insulator-to-metal transition should be possible in semiconducting metal-organic frameworks, but has yet to be observed. The question remains as to whether electro-active hybrid materials will evolve from chemical curiosities towards practical applications in the near term. 相似文献
132.
Kuppermann A 《The journal of physical chemistry. A》2006,110(2):809-816
Hyperspherical harmonics in the democratic row-orthonormal hyperspherical coordinates are very appropriate basis sets for performing reactive scattering calculations for triatomic and tetraatomic systems. The mathematical conditions for incorporating the geometric phase effect in these harmonics are given. These conditions are implemented for triatomic systems, and their explicit analytical expressions in terms of Jacobi polynomials, in both the absence and presence of the geometric phase effect, are given. 相似文献
133.
Chang-Hoon Kim Zentaro Akase Lichun Zhang Arthur H. Heuer Aron E. Newman 《Journal of solid state chemistry》2006,179(3):753-774
The presence of ε-MnO2 as a major component of electrolytic manganese dioxide (EMD) has been demonstrated by a combined X-ray diffraction/transmission electron microscopy (TEM) study. ε-MnO2 usually has a partially ordered defect NiAs structure containing 50% cation vacancies; these vacancies can be fully ordered by a low temperature (200 °C) heat treatment to form a pseudohexagonal but monoclinic superlattice.Numerous fine-scale anti-phase domain boundaries are present in ordered ε-MnO2 and cause extensive peak broadening and a massive shift of a very intense, 0.37 nm superlattice peak. This suggests a radically different explanation of the ubiquitous, very broad ∼0.42 nm peak (∼21-22° 2θ, CuKα radiation) in EMDs, which heretofore has been attributed to Ramsdellite containing numerous planar defects. This work confirms the multi-phase model of equiaxed EMDs proposed by Heuer et al. [ITE Lett. 1(6) (2000) B50; Proc. Seventh Int. Symp. Adv. Phys. Fields 92 (2001)], rather than the defective single-phase model of Chabre and Pannetier [Prog. Solid State Chem. 23 (1995) 1] and Bowden et al. [ITE Lett. 4(1) (2003) B1]. 相似文献
134.
Richard M. Aron Daniel Carando T. W. Gamelin Silvia Lassalle Manuel Maestre 《Mathematische Annalen》2012,353(2):293-303
We investigate uniform algebras of bounded analytic functions on the unit ball of a complex Banach space. We prove several cluster value theorems, relating cluster sets of a function to its range on the fibers of the spectrum of the algebra. These lead to weak versions of the corona theorem for ? 2 and for c 0. In the case of the open unit ball of c 0, we solve the corona problem whenever all but one of the functions comprising the corona data are uniformly approximable by polynomials in functions in ${c_0^*}$ . 相似文献
135.
We consider deformations of unconstrained, isotropic hyperelastic solids which satisfy the condition that the determinant
of the deformation gradient is constant. In the absence of body forces, it is shown (i) that a certain deformation in this
class (which describes the bending of rectangular blocks into annular cylindrical sectors) is not possible in any of the considered
materials, (ii) that in the case when the body fills the whole space, it is composed of a compressible neo-Hookean material
and it is subjected to relatively moderate loads, these deformations are necessarily homogeneous and (iii) that for boundary
conditions of place and relative to a certain sub-class of the class of considered materials, these deformations are globally
stable, in the sense that they are minimizers for the total energy with respect to smooth variations that are compatible with
the boundary conditions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
136.
Phage-displayed alanine shotgun scanning was used to dissect contributions by engrailed homedomain (En-HD) residues 17 through 46, which indirectly influence recognition of DNA. The relative contributions of such indirect contacts, quantified by shotgun scanning, highlight previously unexplored En-HD residues. Two motifs dominate En-HD function in this region. First, two surface-exposed aromatic residues (F20 and Y25) bracket the hydrophobic core. Second, two sets of turn-forming residues are highlighted, including carboxamide-requiring residues E22/N23 and a leucine/isoleucine splint. The En-HD hydrophobic core exhibits a surprising degree of malleability, as demonstrated by homolog shotgun scanning. Most selectants from in vitro shotgun scanning mirror the consensus human homeodomain sequence. Thus, natural evolution and in vitro selection use similar selection criteria: affinity, specificity, and stability. However, homolog shotgun scanning identified mutations capable of improving the affinity and specificity of En-HD. 相似文献
137.
Electron transfer (ET) reactions are one of the most important processes in chemistry and biology. Because of the quantum nature of the processes and the complicated roles of the solvent, theoretical study of ET processes is challenging. To simulate ET processes at the electronic level, we have developed an efficient density functional theory (DFT) quantum mechanical (QM)/molecular mechanical (MM) approach that uses the fractional number of electrons as the order parameter to calculate the redox free energy of ET reactions in solution. We applied this method to study the ET reactions of the aqueous metal complexes Fe(H(2)O)(6)(2+/3+) and Ru(H(2)O)(6)(2+/3+). The calculated oxidation potentials, 5.82 eV for Fe(II/III) and 5.14 eV for Ru(II/III), agree well with the experimental data, 5.50 and 4.96 eV, for iron and ruthenium, respectively. Furthermore, we have constructed the diabatic free energy surfaces from histogram analysis based on the molecular dynamics trajectories. The resulting reorganization energy and the diabatic activation energy also show good agreement with experimental data. Our calculations show that using the fractional number of electrons (FNE) as the order parameter in the thermodynamic integration process leads to efficient sampling and validate the ab initio QM/MM approach in the calculation of redox free energies. 相似文献
138.
García CP Pellegrini V Pinczuk A Rontani M Goldoni G Molinari E Dennis BS Pfeiffer LN West KW 《Physical review letters》2005,95(26):266806
We report inelastic light scattering measurements of spin and charge excitations in nanofabricated AlGaAs/GaAs quantum dots with few electrons. A narrow spin excitation peak is observed and assigned to the intershell triplet-to-singlet monopole mode of dots with four electrons. Configuration-interaction theory provides precise quantitative interpretations that uncover large correlation effects that are comparable to exchange Coulomb interactions. 相似文献
139.
Kai-Oliver Brenske Dr. Meike Emondts Sven T. Hörnig Sinan Panitz Maria I. Pieper Aron Ligori Alexander Schacht Johanna Henkel Prof. Dr. Jürgen Klankermayer Prof. Dr. Andreas Herrmann 《Angewandte Chemie (International ed. in English)》2023,62(22):e202300531
Enhancing NMR signals of biomacromolecules by hyperpolarization offers exciting opportunities for diagnostic applications. However, their hyperpolarization via parahydrogen remains challenging as specific catalytic interactions are required, which are difficult to tune due to the large size of the biomolecule and its insolubility in organic solvents. Herein, we show the unprecedented hyperpolarization of the cancer-targeting DNA aptamer AS1411. By screening different molecular motifs for an unsaturated label in nucleosides and in DNA oligomers, we were able to identify structural prerequisites for the hyperpolarization of AS1411. Finally, adjusting the polarity of AS1411 by complexing the DNA backbone with amino polyethylene glycol chains allowed the hydrogenation of the label with parahydrogen while the DNA structure remains stable to maintain its biological function. Our results are expected to advance hyperpolarized molecular imaging technology for disease detection in the future. 相似文献
140.
M. Aron 《Journal of Elasticity》2000,60(2):165-172
The paper is concerned with solvability of a mixed boundary value problem of place and traction that describes the straightening
of annular cylindrical sectors composed of unconstrained isotropic hyperelastic solids. The existence and uniqueness of solutions
is discussed and several examples are exhibited.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献