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31.
Yue Liu Andy Dang Jan Urban Frantiek Ture
ek 《Angewandte Chemie (International ed. in English)》2020,59(20):7772-7777
Adenosine radicals tagged with a fixed‐charge group were generated in the gas phase and structurally characterized by tandem mass spectrometry, deuterium labeling, and UV/Vis action spectroscopy. Experimental results in combination with Born–Oppenheimer molecular dynamics, ab initio, and excited‐state calculations led to unambiguous assignment of adenosine radicals as N‐7 hydrogen atom adducts. The charge‐tagged radicals were found to be electronically equivalent to natural DNA nucleoside radicals. 相似文献
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Andy K. W. Ma Ali A. Alghamdi Kassem Tofailli Nicholas M. Spyrou 《Journal of Radioanalytical and Nuclear Chemistry》2012,291(2):353-357
Early detection of the red palm weevils (RPW) is a major challenge in agriculture among all kinds of palm trees due to the
nature of the insect and the difficulty to trace them through their life stages associated with the tree life. Many methods
have been applied for the weevil detection such as X-ray diffraction techniques, fluoroscopy and ultrasound. On the other
hand, the idea of tomography has been used for other purposes such as the determination of the age of the tree and for applied
environmental studies. Such technology can also reveal the weevil in principle. In this study, we explore the use of X-ray
CT for weevil detection with the Monte Carlo method. A model of the stem of a palm tree is developed for simulations. MCNPX
is chosen to carry out the simulations for the radiography tally in the code. The tally records the 2D data of the X-ray beams
irradiating the tree model. An iterative reconstruction method for cone beam CT is applied to obtain the 3D slices of the
tree model. We are exploring the minimum number of projection angles and the detectability of the weevil. We shall also report
the sensitivity of weevil detection using X-ray CT with a large set of simulations with different weevil sizes and tree diameters. 相似文献
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Andy Buckley Hendrik Hoeth Heiko Lacker Holger Schulz Jan Eike von Seggern 《The European Physical Journal C - Particles and Fields》2010,65(1-2):331-357
In this article we describe Professor, a new program for tuning model parameters of Monte Carlo event generators to experimental data by parameterising the per-bin generator response to parameter variations and numerically optimising the parameterised behaviour. Simulated experimental analysis data is obtained using the Rivet analysis toolkit. This paper presents the Professor procedure and implementation, illustrated with the application of the method to tunes of the Pythia 6 event generator to data from the LEP/SLD and Tevatron experiments. These tunes are substantial improvements on existing standard choices, and are recommended as base tunes for LHC experiments, to be themselves systematically improved upon when early LHC data is available. 相似文献
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A finitely generated group is called representation rigid (briefly, rigid) if for every n, has only finitely many classes of simple representations in dimension n. Examples include higher rank S-arithmetic groups. By Margulis super rigidity, the latter have a stronger property: they are representation super rigid; i.e., their proalgebraic completion is finite dimensional. We construct examples of nonlinear rigid groups which are not super rigid, and which exhibit every possible type of infinite dimensionality. Whether linear representation rigid groups are super rigid remains an open question. 相似文献
40.
Wood JM Hinchliffe PS Davis AM Austin RP Page MI 《Chemical communications (Cambridge, England)》2002,(7):772-773
The alkaline hydrolysis of N-alpha-methoxycarbonyl benzyl-beta-sultam occurs 10(3) times faster than the corresponding carboxylate and with rapid D-exchange at the alpha-carbon: the pH rate profile indicates pre-equilibirum CH ionisation and together with formation of benzoyl formate as a product this suggests a novel mechanism for hydrolysis. 相似文献