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991.
Goldberg JM Wissner RF Klein AM Petersson EJ 《Chemical communications (Cambridge, England)》2012,48(10):1550-1552
Thioamides quench tryptophan and tyrosine fluorescence in a distance-dependent manner and thus can be used to monitor the binding of thioamide-containing peptides to proteins. Since thioamide analogs of the natural amino acids can be synthetically incorporated into peptides, they can function as minimally-perturbing probes of protein/peptide interactions. 相似文献
992.
Axel Klein Katharina Butsch Sait ElmasChristian Biewer Dominikus Heift Sara NitscheIrene Schlipf Helmut Bertagnolli 《Polyhedron》2012,31(1):649-656
The oxido-pincer ligand pydotH2 (2,6-bis(1-hydroxy-1-o-tolyl-ethyl-η2O,O′)pyridine) forms two different CuII containing complexes when prepared from anhydrous CuCl2. A combination of EPR spectroscopy and EXAFS allowed to structurally characterise the light-green dimer of the formula [(pydotH2)CuCl(μ-Cl)2ClCu(pydotH2)] and the penta-coordinate olive-green monomer [(pydotH2)CuCl2]. The molecular entities imply that the ligand remains protonated upon coordination. When dissolved in DMF both compounds form monomeric species [(pydotH2)CuCl2(DMF)] which could be characterised in detail by EPR, UV-Vis/NIR spectroscopy and electrochemical measurements. The assignments were supported by comparison with CuII complexes of the related ligands 2,6-bis(hydroxymethyl)pyridine (pydimH2) and 2,6-bis(1-hydroxy-1-methyl)pyridine (pydipH2). 相似文献
993.
From solid state reactions of Ag2O, HgO, and Sb2O3 at high temperatures under elevated oxygen pressures a new silver mercury antimonate, Ag5HgSbO6, has been obtained. According to a single crystal structure determination Ag5HgSbO6 crystallizes in space group P$\bar{3}$ 1c (no. 163) with a = 5.9263(4), c = 12.3023(7) Å, V = 374.18(4) Å3, Z = 2, 498 independent reflections, R1 = 0.030, wR2 = 0.059 (I ≥ 2 σ (I). Ag5HgSbO6 consists of HgSbO6 layers, analogous to BiI3, which are separated by Kagome nets formed by Ag+ ions. Perpendicular to these layers and along the c axis linear strings of Ag+ ions run through the large voids of the layers. Accordingly, Ag5HgSbO6 adopts the Ag5Pb2O6 type of structure where the lead positions are occupied by mercury and antimony alternatingly. The finding of mercury in octahedral coordination, particularly besides the lower charged Ag+ cations in linear coordination, which is also highly preferred by Hg2+ ions, is rather unexpected. Ag5HgSbO6 starts to decompose at 450 °C and, in contrast to subvalent and metallic Ag5Pb2O6, the new compound is charge balanced and semiconducting (ρ = 5.7 Ωcm at ambient temperature, Ea = 0.047 eV). 相似文献
994.
We study Markovian stochastic motion on a graph with finite number of nodes and adiabatically periodically driven transition rates. We show that, under general conditions, the quantized currents that appear at low temperatures are a manifestation of topological invariants in the counting statistics of currents. This observation provides an approach for classification of topological properties of the counting statistics, as well as for extensions of the phenomenon of the robust quantization of currents at low temperatures to the properties of the counting statistics which persist to finite temperatures. 相似文献
995.
Klein JM Clegg JK Saggiomo V Reck L Lüning U Sanders JK 《Dalton transactions (Cambridge, England : 2003)》2012,41(13):3780-3786
Six new lanthanide complexes of two 44-membered macrocycles have been prepared and characterised in solution. An analysis of the conformations of the free macrocycles and their lanthanide complexes both in solution (2D NMR) and in solid state (X-ray crystallography) demonstrate that the complexation induces changes in folding of the macrocycles. 相似文献
996.
We extend the bootstrap multi-scale analysis developed by Germinet and Klein to the multi-particle Anderson model, obtaining Anderson localization, dynamical localization, and decay of eigenfunction correlations. 相似文献
997.
The desorption of polymers is studied theoretically and with Monte Carlo simulations. Two regimes can be distinguished: in one regime the detachment of the polymer from the surface is the slowest process, and in the other it is the diffusion of the polymer away from the surface. In both regimes the desorption rate depends on the thickness H of the stagnant layer, i.e. the layer in which the polymer movement is dominated by diffusion. In the diffusion-limited regime the desorption rate scales as H ? 2, as expected for diffusive processes. In the detachment-limited regime the desorption rate scales as H ? 1. The importance of the thickness of the stagnant layer in the detachment-limited regime is due to the fact that the polymer, after it has detached, will most likely readsorb soon after: the probability that the polymer does not readsorb, but crosses the stagnant layer, is inversely proportional to the thickness of the stagnant layer. 相似文献
998.
Abel Klein 《Communications in Mathematical Physics》2013,323(3):1229-1246
We prove a unique continuation principle for spectral projections of Schrödinger operators. We consider a Schrödinger operator H = ?Δ + V on ${{\rm L}^2(\mathbb{R}^d)}$ L 2 ( R d ) , and let H Λ denote its restriction to a finite box Λ with either Dirichlet or periodic boundary condition. We prove unique continuation estimates of the type χ I (H Λ ) W χ I (H Λ ) ≥ κ χ I (H Λ ) with κ > 0 for appropriate potentials W ≥ 0 and intervals I. As an application, we obtain optimal Wegner estimates at all energies for a class of non-ergodic random Schrödinger operators with alloy-type random potentials (‘crooked’ Anderson Hamiltonians). We also prove optimal Wegner estimates at the bottom of the spectrum with the expected dependence on the disorder (the Wegner estimate improves as the disorder increases), a new result even for the usual (ergodic) Anderson Hamiltonian. These estimates are applied to prove localization at high disorder for Anderson Hamiltonians in a fixed interval at the bottom of the spectrum. 相似文献
999.
We show that if R is an infinite ring such that XY ∩ YX ≠ ? for all infinite subsets X and Y, then R is commutative. We also prove that in an infinite ring R, an element a ∈ R is central if and only if aX ∩ Xa ≠ ? for all infinite subsets X. 相似文献
1000.
L. Pogliani D. J. Klein A. T. Balaban 《International Journal of Mathematical Education in Science & Technology》2013,44(4):379-399
Nothing is as difficult to see as the obvious (B. Malinowski) Through the importance of the number three in our culture and the strange preference for a ternary pattern of our nature one can perceive how and why number theory degraded to numerology. The strong preference of our minds for simple patterns can be read as the key to understanding not only the development of numerology, but also why scientists were and are prone to give their discoveries or creations a structure that is based on simple patterns and, among them, especially the ternary pattern. If some numbers seem to appear quite often throughout the fabric of reality, like zero, one, two, and three, reality has, nevertheless, been preferentially analysed in a way to enhance its ternary character. The present excursion through some scientific domains where the ternary pattern has been used tries to offer an answer to the fascination that some numbers, and patterns based on them, exerted and exerts, even today, on human minds. Throughout the overall models created by the human mind, be they natural or spiritual, the models based on a ‘unary’ and on a ‘dualistic’ pattern are surely important, but the model based on a ternary pattern ended up assuming an archetypical character, which is quite intriguing, and deserves to be deepened. The paper is a useful resource for projects for students and background material for teachers of mathematics touching, as it does, on biology, chemistry and physics. 相似文献