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1.
Ruochun Zhang Yulin Qi Chao Ma Jinfeng Ge Qiaozhuan Hu Fu-Jun Yue Si-Liang Li Dietrich A. Volmer 《Molecules (Basel, Switzerland)》2021,26(1)
Lignin is the second most abundant natural biopolymer, which is a potential alternative to conventional fossil fuels. It is also a promising material for the recovery of valuable chemicals such as aromatic compounds as well as an important biomarker for terrestrial organic matter. Lignin is currently produced in large quantities as a by-product of chemical pulping and cellulosic ethanol processes. Consequently, analytical methods are required to assess the content of valuable chemicals contained in these complex lignin wastes. This review is devoted to the application of mass spectrometry, including data analysis strategies, for the elemental and structural elucidation of lignin products. We describe and critically evaluate how these methods have contributed to progress and trends in the utilization of lignin in chemical synthesis, materials, energy, and geochemistry. 相似文献
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A matrix-free homogenization method making use of the fast Fourier transform (FFT) to work on structured grids was introduced by Moulinec and Suquet in 1994. Due to its simplicity and computational advantages, this so-called Basic Scheme has provided the basis for many works in the past two decades. An extension presented by Tran, Monchiet and Bonnet allows for the quasi-static equations of linear elasticity to include effects from higher-order derivatives by expanding the strain and the displacement as asymptotic series. To compute the solution hierarchically, we derive generalized Lippmann Schwinger-type equations. Furthermore, we show how existing algorithms have to be adapted for these problems. (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
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Thomas D. Hettich Richard Rudolf Dr. Christoph M. Feil Nicholas Birchall Dr. Martin Nieger Prof. Dr. Dr. h. c. Dietrich Gudat 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(17):5412-5416
Unprecedented metalated phosphonite boranes were prepared from PH-substituted precursors and silyl amides. Although potassium derivatives were thermally stable and could even be isolated and structurally characterised, lithiated analogues proved to be unstable towards self-condensation under cleavage of LiOR at ambient temperature. Reaction studies revealed that the metalated phosphonite boranes exhibit ambiphilic character. Their synthetic potential as nucleophilic building blocks was demonstrated in the synthesis of the first stannylated phosphonite representing a new structural motif in phosphine chemistry. 相似文献
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Seven new microcystin variants discovered from a native Microcystis aeruginosa strain – unambiguous assignment of product ions by tandem mass spectrometry 下载免费PDF全文
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A. Arockiarajan A. Menzel B. Delibas W. Seemann 《European Journal of Mechanics - A/Solids》2006,25(6):950-964
In this contribution a micromechanically motivated model for rate-dependent switching effects in piezoelectric materials is developed. The proposed framework is embedded into a three-dimensional finite element setting whereby each element is assumed to represent an individual grain. Related dipole (polarization) directions are thereby initially randomly oriented at the element level to realistically capture the originally un-poled state of grains in the bulk ceramics. The onset of domain switching processes is based on a representative energy criterion and combined with a linear kinetics theory accounting for time-dependent propagation of domain walls during switching processes. In addition, grain boundary effects are incorporated by making use of a macromechanically motivated probabilistic approach. Standard volume-averaging techniques with respect to the response on individual grains in the bulk ceramics are later on applied to obtain representative hysteresis and butterfly curves under macroscopically uniaxial loading conditions at different loading frequencies. It turns out that the simulations based on the developed finite element formulation nicely match experimental data reported in the literature. 相似文献
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On the isobaric space of 25‐hydroxyvitamin D in human serum: potential for interferences in liquid chromatography/tandem mass spectrometry,systematic errors and accuracy issues 下载免费PDF全文
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