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211.
Ryan A. Hemming Megan Bell Liam J. Duffy Jonathan Bristow John D. Wallis Steven M. Allin Philip C. Bulman Page 《Tetrahedron》2019,75(1):121-127
A new, versatile and highly stereoselective approach for the synthesis of non-racemic 3-substituted isoindolin-1-ones is described from a readily available chiral template. The potential of this new protocol is demonstrated through the synthesis of an enantiomerically enriched 3-alkyl N-H isoindolin-1-one target with an e.e. of 98%. 相似文献
212.
Zs. Podolyák S. J. Steer S. Pietri M. Górska P. H. Regan D. Rudolph A. B. Garnsworthy R. Hoischen J. Gerl H. J. Wollersheim H. Grawe K. H. Maier F. Becker P. Bednarczyk L. Cáceres P. Doornenbal H. Geissel J. Grebosz A. Kelic I. Kojouharov N. Kurz F. Montes W. Prokopowicz T. Saito H. Schaffner S. Tashenov A. Heinz T. Kurtukian-Nieto G. Benzoni M. Pfützner A. Jungclaus D. L. Balabanski C. Brandau B. A. Brown A. M. Bruce W. N. Catford I. J. Cullen Zs. Dombrádi M. E. Estevez W. Gelletly G. Ilie J. Jolie G. A. Jones M. Kmiecik F. G. Kondev R. Krücken S. Lalkovski Z. Liu A. Maj S. Myalski S. Schwertel T. Shizuma P. M. Walker E. Werner-Malento O. Wieland 《The European Physical Journal A - Hadrons and Nuclei》2009,42(3):489-493
Heavy neutron-rich nuclei have been populated through the relativistic fragmentation of a $\ensuremath ^{208}_{\ 82}{\rm Pb}$ beam at $\ensuremath E/A = 1$ GeV on a $\ensuremath 2.5 {\rm g/cm^2}$ thick Be target. The synthesised nuclei were selected and identified in-flight using the fragment separator at GSI. Approximately 300 ns after production, the selected nuclei were implanted in an $\ensuremath \sim 8$ mm thick perspex stopper, positioned at the centre of the RISING $\ensuremath \gamma$ -ray detector spectrometer array. A previously unreported isomer with a half-life $\ensuremath T_{1/2} = 163(5)$ ns has been observed in the N = 126 closed-shell nucleus $\ensuremath ^{205}_{\ 79}{\rm Au}$ . Through $ \gamma$ -ray singles and $ \gamma$ - $ \gamma$ coincidence analysis a level scheme was established. The comparison with a shell model calculation tentatively identifies the spin-parity of the excited states, including the isomer itself, which is found to be $\ensuremath I^{\pi} = (19/2^+)$ . 相似文献
213.
H. Sawada T. Yabuuchi S.P. Regan K. Anderson M.S. Wei R. Betti J. Hund M.H. Key A.J. Mackinnon H.S. McLean R.R. Paguio P.K. Patel K.M. Saito R.B. Stephens S.C. Wilks F.N. Beg 《High Energy Density Physics》2012,8(2):180-183
Results on diagnoses of laser-driven, shock-heated foam plasma with time-resolved Al 1s-2p absorption spectroscopy are reported. Experiments were carried out to produce a platform for the study of relativistic electron transport. In cone-guided Fast Ignition (FI), relativistic electrons generated by a high-intensity, short-pulse igniter beam must be transported through a cone tip to an imploded core. Transport of the energetic electrons could be significantly affected by the temperature-dependent resistivity of background plasmas. The experiment was conducted using four UV beams of the OMEGA EP laser at the Laboratory For Laser Energetics. One UV beam (1.2 kJ, 3.5 ns square) was used to launch a shock wave into a foam package target, consisting of 200 mg/cm3 CH foam with aluminum dopant and a solid plastic container surrounding the foam layer. The other three UV beams with the total energy of 3.2 kJ in 2.5 ns pulse duration were tightly focused onto a Sm dot target to produce a point X-ray source in the energy range of 1.4–1.6 keV. The quasi-continuous X ray signal was transmitted through the shock-heated Al-doped, foam layer and recorded with an X-ray streak camera. The measured 1s-2p Al absorption features were analyzed using an atomic physics code FLYCHK. Electron temperature of 40 eV inferred from the spectral analysis is consistent with 2-D DRACO Radiation-hydrodynamic simulations. 相似文献
214.
Sangster TC Goncharov VN Radha PB Smalyuk VA Betti R Craxton RS Delettrez JA Edgell DH Glebov VY Harding DR Jacobs-Perkins D Knauer JP Marshall FJ McCrory RL McKenty PW Meyerhofer DD Regan SP Seka W Short RW Skupsky S Soures JM Stoeckl C Yaakobi B Shvarts D Frenje JA Li CK Petrasso RD Séguin FH 《Physical review letters》2008,100(18):185006
The first observation of ignition-relevant areal-density deuterium from implosions of capsules with cryogenic fuel layers at ignition-relevant adiabats is reported. The experiments were performed on the 60-beam, 30-kJUV OMEGA Laser System [T. R. Boehly, Opt. Commun. 133, 495 (1997)10.1016/S0030-4018(96)00325-2]. Neutron-averaged areal densities of 202+/-7 mg/cm2 and 182+/-7 mg/cm2 (corresponding to estimated peak fuel densities in excess of 100 g/cm3) were inferred using an 18-kJ direct-drive pulse designed to put the converging fuel on an adiabat of 2.5. These areal densities are in good agreement with the predictions of hydrodynamic simulations indicating that the fuel adiabat can be accurately controlled under ignition-relevant conditions. 相似文献
215.
Lukasz T. Olenginski Kehinde M. Taiwo Regan M. LeBlanc Theodore K. Dayie 《Molecules (Basel, Switzerland)》2021,26(18)
RNA structural research lags behind that of proteins, preventing a robust understanding of RNA functions. NMR spectroscopy is an apt technique for probing the structures and dynamics of RNA molecules in solution at atomic resolution. Still, RNA analysis by NMR suffers from spectral overlap and line broadening, both of which worsen for larger RNAs. Incorporation of stable isotope labels into RNA has provided several solutions to these challenges. In this review, we summarize the benefits and limitations of various methods used to obtain isotope-labeled RNA building blocks and how they are used to prepare isotope-labeled RNA for NMR structure and dynamics studies. 相似文献
216.
Georgiy Akopov Nethmi W. Hewage Philip Yox Gayatri Viswanathan Shannon J. Lee Liam P. Hulsebosch Sarah D. Cady Alexander L. Paterson Frdric A. Perras Wenqian Xu Kui Wu Yaroslav Mudryk Kirill Kovnir 《Chemical science》2021,12(44):14718
An innovative method of synthesis is reported for the large and diverse (RE)6(TM)x(Tt)2S14 (RE = rare-earth, TM = transition metals, Tt = Si, Ge, and Sn) family of compounds (∼1000 members, ∼325 contain Si), crystallizing in the noncentrosymmetric, chiral, and polar P63 space group. Traditional synthesis of such phases involves the annealing of elements or binary sulfides at elevated temperatures. The atomic mixing of refractory components technique, presented here, allows the synthesis of known members and vastly expands the family to nearly the entire transition metal block, including 3d, 4d, and 5d TMs with oxidation states ranging from 1+ to 4+. Arc-melting of the RE, TM, and tetrel elements of choice forms an atomically-mixed precursor, which readily reacts with sulfur providing bulk powders and large single crystals of the target quaternary sulfides. Detailed in situ and ex situ experiments show the mechanism of formation, which involves multiphase binary sulfide intermediates. Crystal structures and metal oxidation states were corroborated by a combination of single crystal X-ray diffraction, elemental analysis, EPR, NMR, and SQUID magnetometry. The potential of La6(TM)x(Tt)2S14 compounds for non-linear optical applications was also demonstrated.Synthesis from atomically-mixed precursors opens up a phase space to hundreds of chiral and polar sulfide semiconductors with almost any transition metal in variable oxidation states. 相似文献
217.
Azzeddine Bellour Donal O’Regan Mohamed-Aziz Taoudi 《Journal of Applied Mathematics and Computing》2014,46(1-2):67-77
In this paper, we investigate the existence of integrable solution to a nonlinear integral equation, which includes many important integral and functional equations that arise in nonlinear analysis and its applications. Our results are obtained under rather general assumptions. In particular, the solvability of the well known Chandrasekhar equation is discussed under appropriate assumptions. Our analysis uses the technique of measures of weak noncompactness and rely on a variant of Schauder’s fixed point theorem. 相似文献
218.
Valerio Fasano Dr. Liam D. Curless Dr. James E. Radcliffe Dr. Michael J. Ingleson 《Angewandte Chemie (International ed. in English)》2017,56(31):9202-9206
Frustrated Lewis pair (FLP) chemistry enables a rare example of alkyne 1,2-hydrocarbation with N-methylacridinium salts as the carbon Lewis acid. This 1,2-hydrocarbation process does not proceed through a concerted mechanism as in alkyne syn-hydroboration, or through an intramolecular 1,3-hydride migration as operates in the only other reported alkyne 1,2-hydrocarbation reaction. Instead, in this study, alkyne 1,2-hydrocarbation proceeds by a novel mechanism involving alkyne dehydrocarbation with a carbon Lewis acid based FLP to form the new C−C bond. Subsequently, intermolecular hydride transfer occurs, with the Lewis acid component of the FLP acting as a hydride shuttle that enables alkyne 1,2-hydrocarbation. 相似文献
219.
Ravi P. Agarwal Mircea Balaj Donal O’Regan 《Journal of Optimization Theory and Applications》2018,179(3):761-777
In this paper, we establish two intersection theorems which are useful in considering some optimization problems (complementarity problems, variational inequalities, minimax inequalities, saddle point problems). 相似文献
220.
R. Britton J. L. Burnett A. V. Davies P. H. Regan 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):447-452
A GEANT4 based Monte Carlo simulation has been successfully utilised to calculate peak efficiency characterisations and cascade summing (true coincidence summing) corrections in two source geometries commonly used for environmental monitoring. The cascade summing corrections are compared with values generated using an existing (validated) system, and found to be in excellent agreement for all radionuclides simulated. The calculated correction factors and peak efficiencies were also tested by analysing well defined sources used in the operation of the International Monitoring System, which undertakes radionuclide monitoring for verification of the Comprehensive Nuclear-Test-Ban Treaty. All abundances of the radionuclides measured matched the values that were previously determined using proprietary software. Using GEANT4 in this way, cascade summing corrections can now be extended to complex detector models and source matrices, such as Compton Suppression systems. 相似文献