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1.
Johanna Flock Dr. Amra Suljanovic Dr. Ana Torvisco Dr. Wolfgang Schoefberger Birgit Gerke Prof. Dr. Rainer Pöttgen Prof. Dr. Roland C. Fischer Prof. Dr. Michaela Flock 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(46):15504-15517
Stabilization of the central atom in an oxidation state of zero through coordination of neutral ligands is a common bonding motif in transition‐metal chemistry. However, the stabilization of main‐group elements in an oxidation state of zero by neutral ligands is rare. Herein, we report that the transamination reaction of the DAMPY ligand system (DAMPY=2,6‐[ArNH‐CH2]2(NC5H3) (Ar=C6H3‐2,6‐iPr2)) with Sn[N(SiMe3)2]2 produces the DIMPYSn complex (DIMPY=(2,6‐[ArN?CH]2(NC5H3)) with the Sn atom in a formal oxidation state of zero. This is the first example of a tin compound stabilized in a formal oxidation state of zero by only one donor molecule. Furthermore, three related low‐valent SnII complexes, including a [DIMPYSnIICl]+[SnCl3]? ion pair, a bisstannylene DAMPY{SnII[N(SiMe3)2]2}2, and the enamine complex MeDIMPYSnII, were isolated. Experimental results and the conclusions drawn are also supported by theoretical studies at the density functional level of theory and 119Sn Mössbauer spectroscopy. 相似文献
2.
Ajla Aksamija 《Complexity》2009,15(2):45-53
Building design process is a significantly complex procedure taking into account many different factors and variables, such as the site context, environment, material availability, cost, and function. One of the most complex forms in the built environment is tall building because of the scale, design considerations, and multidisciplinary nature. This article discusses development of ontological model for understanding, presenting, relating, and managing knowledge influencing architectural design of tall buildings. Ontology is a knowledge‐based model that represents certain domain by abstraction of concepts, and a network of relationships and properties describing these concepts. By creating an architectural ontology, the factors, relations, and characteristics in the design process can be clearly defined and presented. The model incorporates physical systems such as structure, building elements, and geometry, as well as environmental effects, social aspects and other complex attributes. © 2009 Wiley Periodicals, Inc. Complexity, 2009 相似文献
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When a totally unpolarized light is scattered by a medium that spatially totally depolarizes incident polarized light, the scattered field presents an increase of the order described by the temporal degree of polarization. We analyze the behavior of some polarization and coherence properties in such a physical situation. 相似文献
4.
Amra Tihic Nicolas von Solms Michael L. Michelsen Georgios M. Kontogeorgis Leonidas Constantinou 《Fluid Phase Equilibria》2009
A group contribution (GC) method for estimating pure compound parameters for the molecular-based perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state (EoS) is proposed in a previous work [A. Tihic, G.M. Kontogeorgis, N. von Solms, M.L. Michelsen, L. Constantinou, Ind. Eng. Chem. Res. 47 (2008) 5092–5101]. In this paper, an investigation of the predictive capability of the GC sPC-SAFT EoS through comparison of the method’s predictions for compounds with high molecular weights and several selected binary mixtures of industrial significance with experimental data such as thiols, sulphides and polynuclear aromatics is presented. Additionally, predictions of activity coefficient at infinite dilution for athermal systems are compared with the results using existing activity coefficient models. The results show that calculated pure compound parameters using the proposed GC method allow satisfactory representation of experimental data of investigated systems with the sPC-SAFT EoS. Moreover, the variety of functional groups in the available GC scheme ensures broad applications of the GC sPC-SAFT EoS. 相似文献
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Ryu HJ Aksamija Z Paskiewicz DM Scott SA Lagally MG Knezevic I Eriksson MA 《Physical review letters》2010,105(25):256601
We report thermoelectric measurements on a silicon nanoribbon in which an integrated gate provides strong carrier confinement and enables tunability of the carrier density over a wide range. We find a significantly enhanced thermoelectric power factor that can be understood by considering its behavior as a function of carrier density. We identify the underlying mechanisms for the power factor in the nanoribbon, which include quantum confinement, low scattering due to the absence of dopants, and, at low temperatures, a significant phonon-drag contribution. The measurements set a target for what may be achievable in ultrathin nanowires. 相似文献
7.
Laurent Arnaud Gaëlle Georges Carole Deumié Claude Amra 《Optics Communications》2008,281(6):1739-1744
An experimental procedure, which was found to be valid for both low-level and high-level scattering of random media, was recently shown to directly discriminate between surface and bulk scattering origin [O. Gilbert, C. Deumie, C. Amra, Angle-resolved ellipsometry of scattering patterns from arbitrary surfaces and bulk materials, Opt. Express 13 (2005) 2403]. The method is based on the ellipsometric measurement of the scattered field over the scattering angle and the analysis of the obtained relative phase shift between s and p polarizations. In the case of low-level scattering, the results were already known and have been explained by first order electromagnetic theories. However, information detailing high-level scattering is scarce. Using rigorous electromagnetic theory, we examined high-level scattering. The differential method enabled us to validate the experimental observations of Gilbert et al. (2005) and explore the limits of validity of the discrimination technique. 相似文献
8.
Stefanie Schönberger Amra Blume 《Phosphorus, sulfur, and silicon and the related elements》2014,189(7-8):1226-1236
AbstractThe reaction of P4S10 with dimethyl cyanamide as solvent yields a complex mixture of products, from which the new compound 4,4′-oxybis(2,6-bis(dimethylamino)-4H-1,3,5,4-thiadiazaphosphinine 4-oxide) (1) was isolated. In this pyrophosphate derivative, the phosphorus atoms are part of the, otherwise rarely encountered, 1,3,5,4-thiadiaza-phosphinine ring. The molecular structure of the new compound was elucidated by single-crystal X-ray diffraction, showing an almost planar thiadiazaphosphinine ring and a cis-like arrangement of the heterocycles at the two phosphorus atoms. 相似文献
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Siham Amra Thierry Bataille Saliha Bourouina Bacha Mustapha Bourouina Didier Hauchard 《Electroanalysis》2020,32(6):1346-1353
A new electrochemical sensor based on nanostructured carbon paste electrodes (CPEs) is developed for the sensitive detection of Isoproturon in water. The CPEs were nanostructured by incorporation of carbon nanotubes (NTCs) and synthetized copper oxide nanoparticles (CuO). They were characterized using the X‐ray diffraction spectroscopy (XRD), scanning electron microscopy (SEM) and voltammetric methods. Electrochemical experiments showed that the adsorption of Isoproturon on to (GC‐NTC‐CuO)‐CPE, associated with nanomaterials (NTCs and CuO), provided remarkable analytical performances of the sensor such as a large quantification range from 1 to 200 μg L?1 with a detection limit of 0.1 μg L?1 of Isoproturon and no interferences of some another pesticides tested (specificity of ISO adsorption in acidified water). The tests carried out on real samples of water are conclusive. The analytical performances of the sensor showed that it is suitable for the specific determination of pesticide traces in water. 相似文献
10.
This paper describes a new goniometric optical scattering instrument whose distinctive features include a mobile light source, a telecentric objective, and a fixed photodiode array. A scientific-grade CCD detector allows the instrument to reliably detect BRDF levels as low as , while generating a high-resolution map of light scattered from the sample surface. These data reveal the position and size of localized defects, which can then be excised from the sample to give an unbiased determination of the surface’s intrinsic roughness. High-quality signature and calibration data are also obtained, as well as a practical characterization of a silicon wafer. 相似文献