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11.
A. Dönni P. Fischer A. Furrer P. Bonville F. Hulliger H. R. Ott 《Zeitschrift für Physik B Condensed Matter》1990,81(1):83-88
A polycrystalline smaple of nonstoichiometric ytterbium phosphide, YbP0.84, was investigated by neutron scattering, Mössbauer spectroscopy and bulk magnetic measurements. Neutron diffraction experiments prove the existence of antiferromagnetic type II ordering belowT
N
=0.64 K, in contrast to the observed antiferromagnetic type III ordering in the stoichiometric Kondo-like compounds YbN and YbAs. The temperature dependence of the average ordered magnetic moment per Yb3+ ion with saturation value Yb = 1.03(7)
B
is similar to that of YbN. Mössbauer experiments prove the magnetic phase transition to be first order with different regions in the sample having slightly different transition temperatures. By means of inelastic neutron scattering the crystal-field level scheme was established to be
6 –
8(19meV) –
7(43meV). 相似文献
12.
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15.
Studies on Alkyl Metal Alkoxides of Aluminium, Gallium, and Indium. III. Properties and Vibrational Spectra of Dialkylgallium- and Indium Alkoxides The preparation and the properties of dialkyl metal alkoxides R2MOR′ (with R = CH3, CD3, C2H5; R′ = CH3, CD3 and M = Ga, In) are described. The vibrational data (IR and Raman) of the trimeric methyl derivatives point to puckered six-membered M3O3-ring systems. 相似文献
16.
The dihydronaphthodiphenazine ofKehrmann, which is according toBadger andPettit reported to be 14-o-aminophenyl-13,14-dihydro-5,8,13,14-tetraaza-6,7-benzopentaphene, is N-(o-aminophenyl)-benzo[a]phenazin-5-amine. This was proved by chemical and spectroscopic investigations. The structures of the derivatives prepared byBadger andPettit are also corrected and the acetylation processes are cleared up. 相似文献
17.
In an investigation into the effects of CaCl2 on the sulfation of limestones in a laboratory furnace simulating fluidized-bed coal combustion conditions, small additions of CaCl2 (<1 mole%) to the limestone prior to calcination were found to increase the extent of sulfation by changing the limestone pore structure. These changes were effected by trace amounts of liquid in the system in a synthetic SO2/O2 flue gas at 850°C. At much higher concentrations of CaCl2, large amounts of a liquid phase are produced, containing a substantial quantity of dissolved CaO and leading to greatly enhanced sulfation when exposed to SO2/O2. The use of CaCl2 additive in fluidized-bed combustion would reduce the quantity of limestones required to meet air pollution standards for SO2 and also reduce the quantity of solid waste generated. 相似文献
18.
The regio- and enantioselective alpha-allylation of unstabilized ketone enolates with unsymmetrical allylic carbonates to form the branched substitution products in the presence of metallacyclic iridium catalysts is reported. The products, branched gamma,delta-unsaturated ketones, were obtained from readily available silyl enol ethers and achiral Boc-protected allylic alcohols in high regioselectivities and enantioselectivities (91-96% ee). The combination of CsF and ZnF2 was shown to promote this reaction and suppress the formation of diallylation byproducts. In addition, iridium complexes derived from simple phosphoramidite ligands were shown to catalyze this reaction with excellent selectivities, and spectroscopic data show that a cyclometalated Ir precatalyst is formed in situ. This process provides an enantioselective access to synthetically important bifunctional compounds, which are generally accessible, but in racemic form, through Claisen rearrangements. Ten examples of the reactions of aromatic, as well as aliphatic, substrates are reported. 相似文献
19.
There is a new method of constructing generalized quadrangles (GQs) given by S. Löwe, which is based on covering of nets; all GQs with a regular point can be represented in this way. Here we give a method of constructing GQs with a regular point using the so-called content functions on nets. In the last part of the paper we lay the foundations for a research project aiming to use the more general notion of content to classify GQs and maybe to construct new ones.Both authors acknowledge the financial support by CRUI and DAAD in the frame of Programma Vigoni, which made this work possible. 相似文献
20.