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131.
Markus Winkler Katrin Steinke Ramona Oehme Stefan Berger Dieter Sicker Hans‐Ullrich Siehl Klaus‐Peter Zeller 《Chemie in Unserer Zeit》2014,48(3):190-199
Raffinose has been obtained by extraction with 50% ethanol from the seeds of the Sweet Blue Lupine and purified first via a Cation exchange column and finally by analytical HPLC using a RI‐detector. All analytical spectra were recorded and are reproduced either in the main part or in the supporting information. The NMR‐ and mass‐spectra have been interpreted and compared with theoretical calculations of the 13C chemical shifts. The project is a follow up of the recent book “Classics in Spectroscopy” by S. Berger und D. Sicker (Wiley‐VCH 2009). 相似文献
132.
Katrin Paschke Christian Fiebig Gunnar Blume Alexander Sahm Daniel Jedrzejczyk David Feise Götz Erbert 《Optical Review》2014,21(1):75-78
We demonstrate diode laser modules with high spectral radiance larger than 1 GW/cm2/sr/nm in the visible spectral range. These highly brilliant laser light sources enable the development of next-generation 3D displays. About 1W output power from small-sized modules was achieved at 635 nm by direct diode laser emission and at 530 nm using single pass second harmonic generation (SHG) of a highly brilliant near-infrared laser diode. 相似文献
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136.
Adamczyk K Candelaresi M Kania R Robb K Bellota-Antón C Greetham GM Pollard MR Towrie M Parker AW Hoskisson PA Tucker NP Hunt NT 《Physical chemistry chemical physics : PCCP》2012,14(20):7411-7419
The ultrafast equilibrium fluctuations of the Fe(III)-NO complex of a single point mutation of Myoglobin (H64Q) have been studied using Fourier Transform 2D-IR spectroscopy. Comparison with data from wild type Myoglobin (wt-Mb) shows the presence of two conformational substates of the mutant haem pocket where only one exists in the wild type form. One of the substates of the mutant exhibits an almost identical NO stretching frequency and spectral diffusion dynamics to wt-Mb while the other is distinctly different in both respects. The remarkably contrasting dynamics are largely attributable to interactions between the NO ligand and a nearby distal side chain which provides a basis for understanding the roles of these side chains in other ferric haem proteins. 相似文献
137.
Thomas Heinze Taha Genco Katrin Petzold-Welcke Holger Wondraczek 《Cellulose (London, England)》2012,19(4):1305-1313
Amino cellulose sulfate (ACS); namely 6-deoxy-6-(ω-aminoethyl) amino cellulose-2,3(6)-O-sulfate (AECS) and 6-deoxy-6-(2-(bis-N′,N′-(2-aminoethyl)aminoethyl)) amino cellulose-2,3(6)-O-sulfate (BAECS) were prepared by a three step synthesis starting with the functionalization of microcrystalline cellulose with p-toluenesulfonyl (tosyl) groups (degree of substitution, DSTos between 0.55 and 1.37). Subsequently the introduction of the sulfate moieties was carried out (DSSulf between 1.09 and 1.27) and the tosyl groups at position 6 were replaced by a nucleophilic substitution reaction. As nucleophilic agents 1,2-diaminoethane and tris-(2-aminoethyl)amine were applied, yielding AECS (DSAEA values between 0.41 and 0.86) and BAECS (DSBAEA values between 0.32 and 0.74), respectively. The ACS samples were characterized by means of elemental analysis, 13C-NMR-, FT-IR-, and UV–Vis spectroscopy. Moreover, the solubility of the samples in water at different pH values and the molecular weights of the samples in aqueous solution were studied. 相似文献
138.
Christian Mitterdorfer Jürgen Bernard Frederik Klauser Katrin Winkel Ingrid Kohl Klaus R. Liedl Hinrich Grothe Erwin Mayer Thomas Loerting 《Journal of Raman spectroscopy : JRS》2012,43(1):108-115
Two different polymorphs of carbonic acid, α‐ and β‐H2CO3, were identified and characterized using infrared spectroscopy (FT‐IR) previously. Our attempts to determine the crystal structures of these two polymorphs using powder and thin‐film X‐ray diffraction techniques have failed so far. Here, we report the Raman spectrum of the α‐polymorph, compare it with its FT‐IR spectrum and present band assignments in line with our work on the β‐polymorph [Angew. Chem. Int. Ed. 48 (2009) 2690–2694]. The Raman spectra also contain information in the wavenumber range ∼90–400 cm−1, which was not accessible by FT‐IR spectroscopy in the previous work. While the α‐polymorph shows Raman and IR bands at similar positions over the whole accessible range, the rule of mutual exclusion is obeyed for the β‐polymorph. This suggests that there is a center of inversion in the basic building block of β‐H2CO3 whereas there is none in α‐H2CO3. Thus, as the basic motif in the crystal structure we suggest the cyclic carbonic acid dimer containing a center of inversion in case of β‐H2CO3 and a catemer chain or a sheet‐like structure based on carbonic acid dimers not containing a center of inversion in case of α‐H2CO3. This hypothesis is strengthened when comparing Raman active lattice modes at < 400 cm−1 with the calculated Raman spectra for different dimers. In particular, the intense band at 192 cm−1 in β‐H2CO3 can be explained by the inter‐dimer stretching mode of the centrosymmetric RC(OHO)2 CR entity with ROH. The same entity can be found in gas‐phase formic acid (RH) and in β‐oxalic acid (RCOOH) and produces an intense Raman active band at a very similar wavenumber. The absence of this band in α‐H2CO3 confirms that the difference to β‐H2CO3 is found in the local coordination environment and/or monomer conformation rather than on the long range. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
139.
Christian Fiebig J?rg Fricke Mirko Uebernickel Daniel Jedrzejczyk Alexander Sahm Katrin Paschke 《Optical Review》2012,19(6):405-408
Large-area high-resolution displays, using a flying-spot to create the picture, require light sources in the red, green and blue wavelength range with a high optical output power and nearly diffraction limited beam. In this paper we present experimental results of high-brightness distributed Bragg reflector tapered diode lasers at 106x nm that can be used for single-pass second harmonic generation into the green. Based on these lasers we developed compact (2.5 cm3) green laser modules with an output power of 1W at 53x nm and an electro-optical conversion efficiency of about 5%. The output power stability is better than 2% and the wavelength stability is ±10 pm. The excellent beam quality M ?? 2 < 2 of the green light allows operation in flying spot application systems. Furthermore, we estimate that our concept allows power scaling up to 2W by using nonlinear planar waveguide crystals and into the multi-watt level by spectral beam combining. 相似文献
140.
Using density functional theory (DFT) calculations with an on-site Coulomb repulsion term, we study the composition, stability, and electronic properties of the most common FeOOH surfaces goethite(101), akaganeite(100), and lepidocrocite(010), and their interaction with water. Despite the differences in surface structure, the trends in surface stability of these FeOOH polymorphs exhibit remarkable similarities. We find that the reactivity and the binding configuration of adsorbates depend strongly on the coordination of surface iron: at the fourfold coordinated Fe2 site water is chemisorbed, whereas at the fivefold coordinated Fe1 water is only loosely bound with hydrogen pointing towards the surface. Our results show that the oxidation state of surface iron can be controlled by the surface termination where ferryl (Fe4 +) species emerge for oxygen terminated surfaces and ferrous iron (Fe2 +) at iron and water terminations leading to a reduced band gap. In contrast, the fully hydroxylated surfaces, identified as stable surface configurations at standard conditions from the surface phase diagram, show electronic properties and band gaps closest to bulk FeOOH with ferric surface iron (Fe3 +). Only in the case of goethite(101), a termination with mixed surface hydroxyl and aquo groups is stabilized. 相似文献