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181.
Anthony Manning 《Proceedings Mathematical Sciences》1995,105(3):269-271
A givenn ×n matrix of rational numbers acts onC
π and onQ
π. We assume that its characteristic polynomial is irreducible and compare a basis of eigenvectors forC
π with the standard basis forQ
π. Subject to a hypothesis on the Galois group we prove that vectors from these two bases are as independent of each other
as possible. 相似文献
182.
183.
184.
We report the generation of ultra-short pulses in the VUV (λ = 173.5 nm) using a four-wave mixing technique in magnesium vapour. Using a mode-locked ruby laser as the original source, conversion efficiencies of up to 0.2% and powers of 0.3 MW were obtained. 相似文献
185.
186.
Manning P. Cooke 《Tetrahedron letters》1981,22(5):381-384
A new type of ylide anion is reported which upon alkylation and elimination of triphenylphosphine serves as a vinyl anion equivalent. 相似文献
187.
In this paper, we will apply the Exterior Matrix Method to the case where the governing equations for one piece of the structure is a system of 4 first-order equations. This generalizes a result when the governing equation was a single fourth-order equation. Ironically, the governing equations do not have to be solved in order to find the corresponding exterior matrix, and the exterior matrices can be used to find the eigenfrequencies of the system, even if there are dissipative joints added to the system. We will first look at the well-understood example of Euler–Bernoulli beams to illustrate the concept, and then move on to the more difficult inclined cable problem. 相似文献
188.
Manning T Rhodes E Loftis R Phillips D Demaria D Newman D Rudloe J 《Natural product research》2006,20(5):461-473
The sea squirt Ecteinascidia turbinata produces the powerful drug ET743. In this study Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and Matrix Assisted Laser Desorption Ionization-Mass Spectrometry (MALDI-MS) are systematically used to measure elemental and molecular species in a Florida Keys mangrove ecosystem that contains the sea squirt. ICP-AES is used to measure the concentration of 27 elements down to the parts per billion level in 16 organisms and 3 sediment samples that reside in the mangrove ecosystem including turtle grass, blue crabs, fire sponge, and lettuce slugs. MALDI-MS is used to search for ET743 in these same organisms and sediment samples. A mass spectral feature corresponding to ET743 is identified in the extract of the sea squirt, red mangrove root (Rhizophera mangle), the schoolmaster snapper (Lutjanus griseus), and a sediment sample taken from the ecosystem. We use MALDI-MS to study the impact that various environmental conditions, such as UV light, I(2), cation binding (Fe(+3), Zn(+2), Pb(+2), Cu(+2)), metal oxide nanoparticles (FeO, CuO, TiO(2), ZnO, Al(2)O(3)), a common mineral (CaCO(3)), and extremes in acidity (0.1 M HCl, 0.1 M NaOH) have on the ET743 structure. The data provide potential structures (degradation products, metal-ligand complexes, etc.) that might be present in organism or sedimentary extracts that are similar to ET743. We are studying the marine geochemistry of this ecosystem so a broth can be developed and tested for producing this marine natural product. 相似文献
189.
190.
Jill B. Williamson Sally E. Lewis Robert R. Johnson Irene M. Manning Frank A. Leibfarth 《Angewandte Chemie (International ed. in English)》2019,58(26):8654-8668
Synthetic manipulation of polymer substrates is one of the oldest and most reliable methods to increase the functional diversity of soft materials. Modifying the chemical structure of polymers that are already produced on a commodity scale leverages the current high‐volume and low‐cost production of commodity plastics for the discovery of modern materials. A myriad of polymer C?H functionalization methods have been developed which enable the modification of material properties on both a laboratory and industrial scale. More recently, driven by advances in C?H activation, photoredox catalysis, and radical chemistry, chemoselective approaches have emerged as a means to impart precise functionality onto commodity polymer substrates. This Review discusses the historical significance of and contemporary advances in the C?H functionalization of commodity polymers. The conceptual approach outlined herein presents exciting new directions for the field, including increasing the value of otherwise pervasive materials, uncovering entirely new material properties, and a viable path to upcycle post‐consumer plastic waste. 相似文献