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101.
Results in Mathematics - 相似文献
102.
Maurice François 《Fresenius' Journal of Analytical Chemistry》1909,48(4-5):317-318
Ohne Zusammenfassung 相似文献
103.
Computational Studies on Intramolecular Cycloadditions of Azidoenynes and Azidobutenenitriles to Give 6H‐Pyrrolo[1,2‐c][1,2,3]triazoles and 5H‐Pyrrolo[1,2‐d]tetrazoles 下载免费PDF全文
Gérard Audran Paul Brémond Douniazad El Abed Sylvain R. A. Marque Didier Siri Maurice Santelli 《Helvetica chimica acta》2015,98(7):1018-1027
Energetics of intramolecular cycloadditions of azidoenynes and azidobutenenitriles to give 6H‐pyrrolo[1,2‐c][1,2,3]triazoles and 5H‐pyrrolo[1,2‐d]tetrazoles have been calculated at the B3LYP/6.311++G(3df,3pd) level of theory in ideal gas and in H2O as solvent. Stabilities of the corresponding anions, tautomers, and isomers are discussed. Transition states of the cyclization of parent compounds are determined at the same level of theory. 相似文献
104.
Frontispiece: Combined Spectroscopic and Electrochemical Detection of a NiI⋅⋅⋅HN Bonding Interaction with Relevance to Electrocatalytic H2 Production 下载免费PDF全文
105.
Mathematical Programming - Switching machines on and off is an important aspect of unit commitment problems and production planning problems, among others. Here we study tight mixed integer... 相似文献
106.
Claude Laflamme Maurice Pouzet Norbert Sauer 《Abhandlungen aus dem Mathematischen Seminar der Universit?t Hamburg》2017,87(2):369-408
A tree is scattered if it does not contain a subdivision of the complete binary tree as a subtree. We show that every scattered tree contains a vertex, an edge, or a set of at most two ends preserved by every embedding of T. This extends results of Halin, Polat and Sabidussi. Calling two trees equimorphic if each embeds in the other, we then prove that either every tree that is equimorphic to a scattered tree T is isomorphic to T, or there are infinitely many pairwise non-isomorphic trees which are equimorphic to T. This proves the tree alternative conjecture of Bonato and Tardif for scattered trees, and a conjecture of Tyomkyn for locally finite scattered trees. 相似文献
107.
The stochastic finite element method presented in this Note consists in representing in a probabilistic form the response of a linear mechanical system whose material properties and loading are random. Each input random variable is expanded into a Hermite polynomial series in standard normal random variables. The response (e.g., the nodal displacement vector) is expanded onto the so-called polynomial chaos. The coefficients of the expansion are obtained by a Galerkin-type method in the space of probability. To cite this article: B. Sudret et al., C. R. Mecanique 332 (2004). 相似文献
108.
Druart C Delhomme O de Vaufleury A Ntcho E Millet M 《Analytical and bioanalytical chemistry》2011,399(4):1725-1732
Analysing herbicides in soil is a complex issue that needs validation and optimization of existing methods. An extraction and analysis method was developed to assess concentrations of glyphosate, glufosinate and aminomethylphophonic acid (AMPA) in field soil samples. After testing extractions by accelerated solvent extraction and ultrasonic extraction, agitation was selected with the best recoveries. Water was preferred as solvent extraction because it resulted in a cleaner chromatogram with fewer impurities than was the case with alkaline solvents. Analysis was performed by FMOC pre-column derivatization followed by high-performance liquid chromatography (HPLC) on a 300 mm C(18) column which permitted enhanced separation and sensitivity than a 250 mm C(18) column and increased resistance than the NH(2) column for soil samples. This extraction and analysis method allowing a minimum of steps before the injection in the HPLC with fluorescence detection is efficient and sensitive for a clay-loamy soil with detection limits of 103 μg kg(-1) for glyphosate, 15 μg kg(-1) for glufosinate and 16 μg kg(-1) for AMPA in soil samples. 相似文献
109.
Discrimination of bacteria from Jamaican bauxite soils using laser-induced breakdown spectroscopy 总被引:1,自引:0,他引:1
Lewis DE Martinez J Akpovo CA Johnson L Chauhan A Edington MD 《Analytical and bioanalytical chemistry》2011,401(7):2225-2236
Soil bacteria are sensitive to ecological change and can be assessed to gauge anthropogenic influences and ecosystem health.
In recent years, there has been a significant increase in the focus on new technologies that can be applied to the evaluation
of soil quality. Laser-induced breakdown spectroscopy (LIBS) is a promising technique that has been used for the investigation
and characterization of explosives, solids, liquids, gases, biological and environmental samples. In this study, bacteria
from un-mined and a chronosequence of reclaimed bauxite soils were isolated on Luria–Bertani agar media. Polymerase chain
reaction amplification of the bacterial 16S rDNA, sequencing, and phylogenetic analysis were applied to each isolated soil
bacteria from the sample sites resulting in the identification and classification of the organisms. Femtosecond LIBS performed
on the isolated bacteria showed atomic and ionic emission lines in the spectrum containing inorganic elements such as sodium
(Na), magnesium (Mg), potassium (K), zinc (Zn), and calcium (Ca). Principal component analysis and partial least squares regression
analysis were performed on the acquired bacterial spectra demonstrating that LIBS has the potential to differentiate and discriminate
among bacteria in the un-mined and reclaimed chronosequence of bauxite soils. 相似文献
110.
Ammoniated electrons in dilute frozen solutions are examined using EPR spectroscopy under conditions where the formation of metallic nanoparticles is avoided. Two signals from two different species have been observed. One signal is metastable and decays irreversibly upon annealing. The metastable species saturates at a spin concentration of 10 nM. The annealing temperature for this species amounts to 60 K for frozen solutions of sodium in neat ammonia and is raised upon addition of metal iodide. The observed g value is smaller than the free electron g value and is compatible with a cluster-anion radical rather than with a cavity electron. The wave function of the unpaired electron contains about 6%-10% of 2p character at nitrogen. The observed g shift is fully compatible with previously reported theoretical calculations (Shkrob, I. A. J. Phys. Chem. A 2006, 110, 3967-3976). The second signal cannot be annealed in the frozen state. The line shape is homogeneous, and its width depends on the identity of the metal and at large metal concentrations on the metal concentration itself. Upon increasing alkali metal concentration above 0.15 MPM, the line shape changes from Lorentzian to Dysonian, indicating the presence of metal nanoparticles. A new ENDOR pulse sequence is introduced to investigate the presence of weakly coupled nuclear spins for homogeneous EPR lines. The observations are critically compared with available literature data. 相似文献