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41.
42.
Alexei Borodin Mihail Poplavskyi Christopher D. Sinclair Roger Tribe Oleg Zaboronski 《Communications in Mathematical Physics》2016,346(3):1051-1055
We correct an error in Theorem 12 of the original article concerning the edge scaling limit of the law of real eigenvalues for the real Ginibre ensemble. 相似文献
43.
Xuejie Zhang Yan Xu Andrew K. Abel Leslie S. Smith Roger Watt Amir Hussain Chengxiang Gao 《Entropy (Basel, Switzerland)》2020,22(12)
Extraction of relevant lip features is of continuing interest in the visual speech domain. Using end-to-end feature extraction can produce good results, but at the cost of the results being difficult for humans to comprehend and relate to. We present a new, lightweight feature extraction approach, motivated by human-centric glimpse-based psychological research into facial barcodes, and demonstrate that these simple, easy to extract 3D geometric features (produced using Gabor-based image patches), can successfully be used for speech recognition with LSTM-based machine learning. This approach can successfully extract low dimensionality lip parameters with a minimum of processing. One key difference between using these Gabor-based features and using other features such as traditional DCT, or the current fashion for CNN features is that these are human-centric features that can be visualised and analysed by humans. This means that it is easier to explain and visualise the results. They can also be used for reliable speech recognition, as demonstrated using the Grid corpus. Results for overlapping speakers using our lightweight system gave a recognition rate of over 82%, which compares well to less explainable features in the literature. 相似文献
44.
45.
The morphological evolution of pyramids, developed on bombarded copper surfaces, as a function of consecutive doses of 12 keV Kr—ions from 2.4 × 1016 up to 3 × 1016 ions/cm2, has been studied. In disagreement with many previous studies, apparently based on a limited choice of doses which were sometimes not in sequence, we found that the pyramids disappeared at high enough doses. Pyramids are therefore not an equilibrium structure. 相似文献
46.
Roger D. Amos 《Molecular physics》2013,111(4):1125-1135
A method recently introduced for constructing spin-coupled wave-functions is extended to deal with the singlet and triplet states of four-electron systems. The approach is applied to LiH (1Σ, 3Σ), Be (1 S) and BeH+ (1Σ) using a simple one-configuration model, in which the orbitals are expressed in elliptical coordinates. 相似文献
47.
Christelle Mouveaux Fabienne Hochart Joëlle Levalois-Mitjaville Roger De Jaeger 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract Multisite receptors containing more than two macrocyclic cavities. despite of the fact that their syntheses, most often, require sophisticated pathways, arc of very high interest since they may allow new insights into ion channel transfer, ion conduction.[1] We report here a method which combine simple reactions, high yields (80%), with easily prepared starting reagents[2], of two new polymacrocyclic system, a tri-(r) and an hexamacrocyck(II). They were obtained by a condensation reaction between 4-formylbenzo-15-crown-5 (3 or 6 quiv, respectively) and phosphouihydrazide (1 equiv.) or hexahydrazide (1 equiv.) in tetrahydrofuran. 相似文献
48.
Abdeslam Meliani Yann Vaugeois Hamza Bali Ahmed Mazzah Roger de Jaeger Jean Habimana 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):283-301
Abstract 31P NMR investigation has been made of the action of Cl3P[dbnd]N-POCl2(I) first on hexamethyldisiloxane (Me3Si)2O and then on oligosiloxanes Me3Si-(OSiMe2)n-OSiMe3 n = 2 and n=3. The reactions were carried out in bulk or in solution with molar ratios siloxane/(I) varying from I to 5. It was demonstrated that only the monosubstitution of a chlorine atom by the -(OSiMe2)n,-OSiMe3 species n = 0, 2, 3 with elimination of trimethylchlorosilane occurred leading to the derivatives Cl2OP-N[dbnd]PCl2O(SiMe2-O)nSiMe3 (II). For n=2, 3 the siloxane redistribution reactions were observed by 29Si NMR analysis. A two steps mechanism is proposed. consisting in a nucleophilic substitution, involving a tricoordinate phosphazenium intermediate, followed by the formation of an active ionic centre probably an oxonium ion, arising from the solvatation by the siloxane of this phosphazeniurn ion and /or of (II) leading to the redistribution reactions. The influences of the solvent, of trimethylchlorosilane, of the temperature, and of the addition of a protonated species (MDH) were investigated. 相似文献
49.
Andrzej Chmura Sven Rustler Monica Paravidino Fred van Rantwijk Andreas Stolz Roger A. Sheldon 《Tetrahedron: Asymmetry》2013,24(19):1225-1232
Enantiomerically pure (S)-mandelic acid was synthesised from benzaldehyde by sequential hydrocyanation and hydrolysis in a bienzymatic cascade at starting concentrations up to 0.25 M. A cross-linked enzyme aggregate (CLEA) composed of the (S)-selective oxynitrilase from Manihot esculenta and the non-selective nitrilase from Pseudomonas fluorescens EBC 191 was employed as the biocatalyst. The nitrilase produces approx. equal amounts of (S)-mandelic acid and (S)-mandelic amide from (S)-mandelonitrile under standard conditions, but we surprisingly found that high (up to 0.5 M) concentrations of HCN induced a marked drift towards amide production. By including the amidase from Rhodococcus erythopolis in the CLEA we obtained (S)-mandelic acid as the sole product in 90% yield and >99% enantiomeric purity. 相似文献
50.
Andrew S. Rowan Thomas S. Moody Roger M. Howard Toby J. Underwood Iain R. Miskelly Yanan He Bo Wang 《Tetrahedron: Asymmetry》2013,24(21-22):1369-1381
Libraries of highly enantioenriched secondary alcohols in both enantiomeric forms were synthesised by enzymatic reduction of their parent ketones using selectAZyme? carbonyl reductase (CRED) technology. Commercially available CREDs were able to reduce a range of substrate classes efficiently and with very high enantioselectivity. Matching substrate classes to small subsets of CREDs enabled the fast development of preparative bioreductions and the rapid generation of 100–1500 mg samples of chiral alcohols in typically >95% ee and the majority in ?99.0% ee. The conditions for small scale synthesis were then scaled up to 0.5 kg to deliver one of the chiral alcohols, (S)-1-(4-bromophenyl)-2-chloroethanol, in 99.8% ee and 91% isolated yield. 相似文献