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1.
ágnes Zsigmond Ramóna Madácsi Ferenc Notheisz Erzsébet Mernyák and Ferenc Joó 《Reaction Kinetics and Catalysis Letters》2006,87(2):297-304
Summary [RuCl2(PPh3)3], [{RuCl2(TPPMS)2}2] and their heterogenized analogs were applied in the selective hydrogenation of 17-keto- and α,β-unsaturated ketosteroids.
In basic conditions these complexes selectively hydrogenated the C=O bonds, similarly to the results obtained in the case
of α,β-unsaturated aldehydes. A new method was developed for the synthesis of an expensive steroid alcohol, which can be prepared
traditionally in a more complicated way. 相似文献
2.
The deoxygenation of methyloxirane to propene and its isomerization to oxo compounds on a Ni/SiO2 catalyst were studied in a pulse microreactor, in the presence of H2 as carrier gas, at 473 K. It was found that the deoxigenation leads to the creation of new types of active centers (Lewis acid site-basic site), which cause a change in the direction of ring opening. The differences in regioselectivity observed between Ni and Cu, and Pt and Pd, can be explained by the different affinities of the metals for oxygen. This finding can be generalized to other oxygen-containing compounds.
Part IV: J. Catal. (to be published) 相似文献
=qa Ni/SiO2 473 . , - - , . Ni Cu, Pt Pd . .
Part IV: J. Catal. (to be published) 相似文献
3.
János B. Czirok Ákos Tarcsay Pál D. Mezei András Simon László Balázs 《Supramolecular chemistry》2013,25(10-12):722-728
The size limit of substituents allowing O-through-the-annulus rotation of substituted calix[4]arenes was further extended to the propargyloxy group in 24-propargyloxy-25,26,27-tris(N,N-dimethylcarbamoylmethoxy)-p-tert-butylcalix[4]arene by demonstrating its free but slow motion affording equilibrium between the partial cone and 1,2-alternate conformers. The effect of solvent and upper rim substituents R1 on the conformational inversion was investigated by means of 1H NMR. The rotational isomerisation of the parent (R1 = H) analogue could not unambiguously be detected. The experimental results were supported by comprehensive density functional theory studies. 相似文献
4.
A. Anghel T. L. Bailey G. Bison B. Blau L. J. Broussard S. M. Clayton C. Cude-Woods M. Daum A. Hawari N. Hild P. Huffman T. M. Ito K. Kirch E. Korobkina B. Lauss K. Leung E. M. Lutz M. Makela G. Medlin C. L. Morris R. W. Pattie D. Ries A. Saunders P. Schmidt-Wellenburg V. Talanov A. R. Young B. Wehring C. White M. Wohlmuther G. Zsigmond 《The European Physical Journal A - Hadrons and Nuclei》2018,54(9):148
5.
Ban G Bodek K Daum M Henneck R Heule S Kasprzak M Khomutov N Kirch K Kistryn S Knecht A Knowles P Kuźniak M Lefort T Mtchedlishvili A Naviliat-Cuncic O Plonka C Quéméner G Rebetez M Rebreyend D Roccia S Rogel G Tur M Weis A Zejma J Zsigmond G 《Physical review letters》2007,99(16):161603
In case a mirror world with a copy of our ordinary particle spectrum would exist, the neutron n and its degenerate partner, the mirror neutron n', could potentially mix and undergo nn' oscillations. The interaction of an ordinary magnetic field with the ordinary neutron would lift the degeneracy between the mirror partners, diminish the n' amplitude in the n wave function and, thus, suppress its observability. We report an experimental comparison of ultracold neutron storage in a trap with and without superimposed magnetic field. No influence of the magnetic field is found and, assuming negligible mirror magnetic fields, a limit on the oscillation time taunn' > 103 s (95% C.L.) is derived. 相似文献
6.
M. Daum P. FierlingerB. Franke P. GeltenbortL. Goeltl E. GutsmiedlJ. Karch G. KesslerK. Kirch H.-C. KochA. Kraft T. LauerB. Lauss E. PierreG. Pignol D. ReggianiP. Schmidt-Wellenburg Yu. SobolevT. Zechlau G. Zsigmond 《Physics letters. [Part B]》2011,704(5):456-460
Ultracold neutrons were stored in a volume, using a magnetic dipole field shutter. Radial confinement was provided by material walls. Low-field seeking neutrons were axially confined above the magnetic field. High-field seeking neutrons are trapped inside the magnetic field. They can systematically shift the measured neutron lifetime to lower values in experiments with magnetic confinement. 相似文献
7.
We provide a short, elementary proof of the existence and uniqueness of the square root in the context of unbounded positive selfadjoint operators on real or complex Hilbert spaces. 相似文献
8.
The decays Higgs → Higgs + V (V = W, Z) are studied in the Weinberg-Salam model with two Higgs doublets and are shown to exceed the usual fermion decay mode with known fermions and the mode V in a large region of Higgs masses and mixing angles. Higgs-Higgs final states and the role of the heavy Higgs decays are briefly discussed. 相似文献
9.
10.
Z. Chowdhuri M. Fertl M. Horras K. Kirch J. Krempel B. Lauss A. Mtchedlishvili D. Rebreyend S. Roccia P. Schmidt-Wellenburg G. Zsigmond 《Applied physics. B, Lasers and optics》2014,115(2):257-262
We report on a comparison of spin relaxation rates in a 199Hg magnetometer using different wall coatings. A compact mercury magnetometer was built for this purpose. Glass cells coated with fluorinated materials show longer spin coherence times than if coated with their hydrogenated homologues. The longest spin relaxation time of the mercury vapor was measured with a fluorinated paraffin wall coating. 相似文献