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Francis E. Burstall Udo Hertrich-Jeromin Wayne Rossman 《Comptes Rendus Mathematique》2012,350(7-8):413-416
We show how linear Weingarten surfaces appear as special Ω-surfaces and give a characterization of those linear Weingarten surfaces that allow a Weierstrass type representation. 相似文献
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Jochen Rau 《Physics letters. A》2012,376(4):370-373
In quantum state tomography, one potential source of error is uncontrolled contact of the system with a heat bath whose detailed properties are not known, and whose impact on the system moreover varies between different runs of the experiment. Precisely these variations provide a handle for reconstructing the system?s effective relaxation dynamics. I propose a pertinent estimation scheme which is based on a steepest-descent ansatz and maximum likelihood. After reconstructing the relaxation dynamics, the original quantum state of the system can be constrained to a curve in state space. 相似文献
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Pascal Wintergerst Kamil Witas Djawed Nauroozi Marie-Ann Schmid Ebru Dikmen Stefanie Tschierlei Sven Rau 《无机化学与普通化学杂志》2020,646(13):842-848
The synthesis of alkyne functionalized bipyridine ruthenium complexes are reported. The improved synthetic approach through application of stable protecting groups prevents formation of possible side products while facilitating purification. By applying copper-catalysed azide-alkyne cycloaddition reactions (CuAAC) pyrene units with flexible alkyl linkers are introduced at the periphery of the complex, opening up various applications including surface immobilization and DNA intercalation. All complexes are characterized structurally as well as photophysically, especially regarding the influence of the introduced alkyne and triazolyl substituents on their photophysical behavior. 相似文献
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A Facile Route to Backbone‐Tethered N‐Heterocyclic Carbene (NHC) Ligands via NHC to aNHC Rearrangement in NHC Silicon Halide Adducts
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Heidi Schneider Dr. David Schmidt Prof. Dr. Udo Radius 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2793-2797
The reaction of 1,3‐diisopropylimidazolin‐2‐ylidene (iPr2Im) with diphenyldichlorosilane (Ph2SiCl2) leads to the adduct (iPr2Im)SiCl2Ph2 1 . Prolonged heating of isolated 1 at 66 °C in THF affords the backbone‐tethered bis(imidazolium) salt [(aHiPr2Im)2SiPh2]2+ 2 Cl? 2 (“a” denotes “abnormal” coordination of the NHC), which can be synthesized in high yields in one step starting from two equivalents of iPr2Im and Ph2SiCl2. Imidazolium salt 2 can be deprotonated in THF at room temperature using sodium hydride as a base and catalytic amounts of sodium tert‐butoxide to give the stable N‐heterocyclic dicarbene (aiPr2Im)2SiPh2 3 , in which two NHCs are backbone‐tethered with a SiPh2 group. This easy‐to‐synthesize dicarbene 3 can be used as a novel ligand type in transition metal chemistry for the preparation of dinuclear NHC complexes, as exemplified by the synthesis of the homodinuclear copper(I) complex [{a(ClCu?iPr2Im)}2SiPh2] 4 . 相似文献
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The Potential of O‐MMT as a Reinforcing Filler for Uncured and Dynamically Cured PVC/XNBR Composites
Organic montmorillonite modified with quaternary ammonium (O‐MMT) was compounded with uncured and dynamically cured poly(vinyl chloride)/carboxylated nitrile butadiene rubber (PVC/XNBR) composites, using a Brabender Plasticorder at 130°C and 50 rpm rotor speed. The reinforcing efficiency of the O‐MMT was investigated in the uncured PVC/XNBR composite and the dynamically cured PVC/XNBR counterpart. Mixing and dynamic curing of the composites were monitored by typical torque‐time curves derived from a Brabender internal mixer. The torque‐time curves revealed that the dynamic curing process was successful and the incorporation of O‐MMT has no adverse effect on the processibility of the composites. It has been found that the introduction of crosslinks within the rubbery phase in the presence of the O‐MMT has further improved the tensile properties. DMA studies revealed that dynamically cured composite with O‐MMT showed higher storage modulus than the composite without O‐MMT. Furthermore, a one‐step tensile modulus vs. temperature curve and a related one peak tensile loss modulus vs. temperature curve were obtained, consequently, both are characteristics of a miscible polymers system. Further evidence on the composite miscibility was purchased by thermal scans from DSC, which showed a single glass transition temperature of PVC/XNBR composites. This claim was further supported by ATR‐IR spectra which revealed that hydrogen bonding is extensively involved in PVC/XNBR composites. This evidence unveiled the exact nature of the specific interactions responsible for miscibility and hence, enhanced mechanical properties. Furthermore, we proved in our studies the reinforcing role played by layered clay due to better dispersion, as well as improved interactions. 相似文献
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Peter Fechner Oliver Bleher Melanie Ewald Kathrin Freudenberger Dominik Furin Urs Hilbig Felix Kolarov Katrin Krieg Lothar Leidner Goran Markovic Günther Proll Florian Pröll Sabrina Rau Johannes Riedt Barbara Schwarz Patricia Weber Julia Widmaier 《Analytical and bioanalytical chemistry》2014,406(17):4033-4051
This review is focused on methods for detecting small molecules and, in particular, the characterisation of their interaction with natural proteins (e.g. receptors, ion channels). Because there are intrinsic advantages to using label-free methods over labelled methods (e.g. fluorescence, radioactivity), this review only covers label-free techniques. We briefly discuss available techniques and their advantages and disadvantages, especially as related to investigating the interaction between small molecules and proteins. The reviewed techniques include well-known and widely used standard analytical methods (e.g. HPLC-MS, NMR, calorimetry, and X-ray diffraction), newer and more specialised analytical methods (e.g. biosensors), biological systems (e.g. cell lines and animal models), and in-silico approaches. 相似文献
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Julia Rebholz Peter Bonanati Udo Weimar Nicolae Barsan 《Analytical and bioanalytical chemistry》2014,406(16):3977-3983
A model for sensing with semiconducting metal oxide (SMOX)-based gas sensors was developed which takes the effect of the shape of the grains in the sensing layers into account. Its validity is limited to materials in which the grains of the SMOX sensing layer are large enough to have an undepleted bulk region (large grains). This means that in all experimental conditions, the SMOX properties ensure that the influence of surface phenomena is not extended to the whole grain. The model takes the surface chemistry and its impact on the electrical properties of the sensing material into consideration. In this way, it relates the sensor signal—defined as the relative change of the sensor’s conductance—directly to the concentration of the target gas and also exhibits meaningful chemical parameters, such as the type of reactive oxygen species, the reaction constants, and the concentration of adsorption sites. The validity of the model is confirmed experimentally by applying it to data gathered by measuring homemade sensors in relevant conditions. 相似文献
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