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51.
Maul J Strachnov I Eberhardt K Karpuk S Passler G Trautmann N Wendt K Huber G 《Analytical and bioanalytical chemistry》2006,386(1):109-118
A combined setup for spatially resolved mass analysis of trace amounts of elements and macromolecules is presented. Using
a MALDI-TOF mass spectrometer, a laser spectroscopic setup for resonant ionization of neutral atoms has been implemented.
This allows for an efficient and selective detection of trace elements by means of resonance ionization mass spectrometry
(RIMS). The instrumental scheme is described, and methodological developments are presented. In a first application pure,
laser desorption/ionization with TOF-MS was used to measure mass distributions of cosmic nanodiamonds. For further applications
regarding the spatially resolved ultra-trace analysis of elements in solid samples, an implanted target was used to characterize
both laser desorption/ionization and laser desorption/resonance ionization for the detection of trace elements within. A perspective
of the setup is given and future investigations are outlined. 相似文献
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In type III seesaw utilized to explain the observed solar and atmospheric neutrino oscillations the Standard Model (SM) particle spectrum is extended by introducing three SU(2)L triplet fermion fields. This can have important implications for the SM Higgs boson mass (MH) bounds based on vacuum stability and perturbativity arguments. We compute the appropriate renormalization group equations for type III seesaw, and then proceed to identify regions of the parameter space such that the SM Higgs boson mass window is enlarged to 125 GeV?MH?174 GeV, with the type III seesaw scale close to TeV. We also display regions of the parameter space for which the vacuum stability and perturbativity bounds merge together for large neutrino Yukawa couplings. Comparison with type I seesaw is also presented. 相似文献
56.
We consider random conformally invariant paths in the complex plane (SLEs). Using the Coulomb gas method in conformal field theory, we rederive the mixed multifractal exponents associated with both the harmonic measure and winding (rotation or monodromy) near such critical curves, previously obtained by quantum gravity methods. The results also extend to the general cases of harmonic measure moments and winding of multiple paths in a star configuration. 相似文献
57.
Gang Yan Bereket L. Zekarias Dr. Xiaoyu Li Victor A. Jaffett Ilia A. Guzei Prof. Dr. Jennifer E. Golden 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(11):2486-2492
A highly efficient 2-chloroquinazolin-4(3H)-one rearrangement was developed that predictably generates either twisted-cyclic or ring-fused guanidines in a single operation, depending on the presence of a primary versus secondary amine in the accompanying diamine reagent. Exclusive formation of twisted-cyclic guanidines results from pairing 2-chloroquinazolinones with secondary diamines. Use of primary amine-containing diamines permits a domino quinazolinone rearrangement/intramolecular cyclization, gated through (E)-twisted-cyclic guanidines, to afford ring-fused N-acylguanidines. This scalable, structurally tolerant transformation generated 55 guanidines and delivered twisted-cyclic guanidines with robust plasma stability and an abbreviated total synthesis of an antitumor ring-fused guanidine (4 steps, 55 % yield). 相似文献
58.
Hanfi Mohamed Y. Yarmoshenko Ilia V. Seleznev Andrian A. Zhukovsky Michael V. 《Journal of Radioanalytical and Nuclear Chemistry》2019,320(3):831-839
Journal of Radioanalytical and Nuclear Chemistry - A castable polyurethane (PUR) with soft segment made by polytetrahydrofuran polyol (or polytretramethylene ether glycol?=?PTMEG)... 相似文献
59.
Chase A. Salazar Joseph J. Gair Kaylin N. Flesch Ilia A. Guzei Jared C. Lewis Shannon S. Stahl 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(27):10965-10969
Mono-N-protected amino acids (MPAAs) are increasingly common ligands in Pd-catalyzed C−H functionalization reactions. Previous studies have shown how these ligands accelerate catalytic turnover by facilitating the C−H activation step. Here, it is shown that MPAA ligands exhibit a second property commonly associated with ligand-accelerated catalysis: the ability to support catalytic turnover at substoichiometric ligand-to-metal ratios. This catalytic role of the MPAA ligand is characterized in stoichiometric C−H activation and catalytic C−H functionalization reactions. Palladacycle formation with substrates bearing carboxylate and pyridine directing groups exhibit a 50–100-fold increase in rate when only 0.05 equivalents of MPAA are present relative to PdII. These and other mechanistic data indicate that facile exchange between MPAAs and anionic ligands coordinated to PdII enables a single MPAA to support C−H activation at multiple PdII centers. 相似文献
60.
Jixin Qiao Petra Lagerkvist Ilia Rodushkin Susanna Salminen-Paatero Per Roos Syverin Lierhagen Karl Andreas Jensen Emma Engstrom Yann Lahaye Lindis Skipperud 《Journal of Radioanalytical and Nuclear Chemistry》2018,315(3):565-580
Inductively coupled plasma mass spectrometry (ICP-MS) techniques are widely used for determination of long-lived radionuclides and their isotopic ratios in the nuclear fields. Uranium (U) and Plutonium (Pu) isotopes have been determined by many researchers with ICP-MS due to its relatively high sensitivity and short measurement time. In this work, an inter-laboratory comparison exercise among the Nordic countries was performed, focusing on the measurement of U and Pu isotopes in certified reference materials by ICP-MS. The performance and characters of different ICP-MS instruments are evaluated and discussed in this paper. 相似文献