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991.
Konrad Schwarz 《Discrete Applied Mathematics》2011,159(15):1608-1616
An algorithm for automatic drawing of quasi-median networks is proposed that uses Eulerian cycles in the non-strong-compatibility graph to lay out the network in the plane. 相似文献
992.
Janusz Matkowski 《Acta Mathematica Hungarica》2011,132(1-2):92-106
Without any regularity conditions, we determine all the Cauchy means C [f,g] that are invariant with respect to the mean-type mapping (L [f],L [g]) where L [f] denotes the Lagrangean mean generated by f. Applications in iteration theory and functional equation are given. 相似文献
993.
994.
Laura Mueller Wojciech Jakubowski Krzysztof Matyjaszewski Joanna Pietrasik Piotr Kwiatkowski Wojciech Chaladaj Janusz Jurczak 《European Polymer Journal》2011,(4):730-734
High molecular weight polystyrene (PS) was synthesized by ATRP. Under atmospheric pressure (1 bar), PS with Mn up to 200,000 was prepared using either ARGET or ICAR ATRP. Under high pressure (6 kbar), higher molecular weight PS could be obtained due to accelerated radical propagation and diminished radical termination in polymerization of styrene. Therefore, it was possible to synthesize PS with Mn > 1,000,000 and Mw/Mn < 1.25 using AGET ATRP under a pressure of 6 kbar at room temperature. This is the highest molecular weight linear PS prepared by a controlled radical polymerization. 相似文献
995.
We propose a rigorous method for removing rigid-body motions from a given molecular dynamics trajectory of a flexible macromolecule. The method becomes exact in the limit of an infinitesimally small sampling step for the input trajectory. In a recent paper [G. Kneller, J. Chem. Phys. 128, 194101 (2008)], one of us showed that virtual internal atomic displacements for small time increments can be derived from Gauss' principle of least constraint, which leads to a rotational superposition problem for the atomic coordinates in two consecutive time frames of the input trajectory. Here, we demonstrate that the accumulation of these displacements in a molecular-fixed frame, which evolves in time according to the virtual rigid-body motions, leads to the desired trajectory for internal motions. The atomic coordinates in the input and output trajectory are related by a roto-translation, which guarantees that the internal energy of the molecule is left invariant. We present a convenient implementation of our method, in which the accumulation of the internal displacements is performed implicitly. Two numerical examples illustrate the difference to the classical approach for removing macromolecular rigid-body motions, which consists of aligning its configurations in the input trajectory with a fixed reference structure. 相似文献
996.
997.
Barbara Bojko Erasmus Cudjoe Janusz Pawliszyn Marcin Wasowicz 《Trends in analytical chemistry : TRAC》2011,30(9):1505-1512
The current review briefly discusses the future development of solid-phase microextraction (SPME) and its potential application in the field of clinical medicine, including pharmacokinetic studies, therapeutic drug monitoring, biomarker discovery, and targeted and untargeted metabolomics. We also discuss aspects of automation and high-throughput analysis as major requirements of daily clinical practice. We give examples of clinically-validated applications of SPME and point out the regulatory restrictions limiting some in-vivo SPME studies. We briefly review the current state of progress in this extraction technique in the context of its future application in medical research and laboratory testing, including new directions (i.e. personalized medicine). 相似文献
998.
We employ state-of-the-art methods and basis sets to study the effect of inserting the Xe atom into the water molecule and the water dimer on their NMR parameters. Our aim is to obtain predictions for the future experimental investigation of novel xenon complexes by NMR spectroscopy. Properties such as molecular structure and energetics have been studied by supermolecular approaches using HF, MP2, CCSD, CCSD(T) and MP4 methods. The bonding in HXeOH···H(2)O complexes has been analyzed by Symmetry-Adapted Perturbation Theory to provide the intricate insight into the nature of the interaction. We focus on vibrational spectra, NMR shielding and spin-spin coupling constants-experimental signals that reflect the electronic structures of the compounds. The parameters have been calculated at electron-correlated and Dirac-Hartree-Fock relativistic levels. This study has elucidated that the insertion of the Xe atom greatly modifies the NMR properties, including both the electron correlation and relativistic effects, the (129)Xe shielding constants decrease in HXeOH and HXeOH···H(2)O in comparison to Xe atom; the (17)O, as a neighbour of Xe, is deshielded too. The HXeOH···H(2)O complex in its most stable form is stabilized mainly by induction and dispersion energies. 相似文献
999.
E. Skwarek S. Khalameida W. Janusz V. Sydorchuk N. Konovalova V. Zazhigalov J. Skubiszewska-Zi?ba R. Leboda 《Journal of Thermal Analysis and Calorimetry》2011,106(3):881-894
Mechanochemical activation of individual V2O5, MoO3 and mixed vanadium-molybdenum oxide system in various media (air, water, and ethanol) has been studied. Powder X-ray diffraction, nitrogen adsorption?Cdesorption, thermogravimetric and chemical analysis, FTIR and Raman spectroscopy, and scanning electron microscopy have been used for research of prepared milled samples. The electrokinetic properties (dependence zeta potential??pH, position of isoelectric point) of individual V2O5, MoO3 and mixed vanadium?Cmolybdenum oxide system, synthesized via mechanochemical treatment in various medium, in aqueous solutions of electrolytes also have been determined. Initial, milled, and spent samples are characterized with the help of XRD, FTIR and Raman spectroscopy, and SEM and adsorption of nitrogen. The catalytic properties of vanadium?Cmolybdenum oxide composition activated in different media have been investigated in reaction of oxidation dehydrogenation of propane. 相似文献
1000.
Hindelang K Vagin SI Anger C Rieger B 《Chemical communications (Cambridge, England)》2012,48(23):2888-2890
A sequence of two new post-synthetic modifications, epoxidation using dimethyldioxirane and subsequent epoxide ring-opening, was developed, maintaining the MOF network. A kinetic study shows that the functionalization of metal-organic frameworks with synthetically versatile and reactive oxirane groups is even possible for small pore diameters. 相似文献