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排序方式: 共有491条查询结果,搜索用时 31 毫秒
71.
P. Grünberg C.M. Mayr W. Vach M. Grimsditch 《Journal of magnetism and magnetic materials》1982,28(3):319-325
We have used the new technique of Brillouin scattering from spinwaves in thin films for a determination of their magnetic parameters. Films of Fe, Ni and Ni0.8Fe0.2 (permalloy) have been investigated and we find good agreement with the results obtained by other methods. We also display spectra from all three materials and discuss some of their characteristic features. For Fe epitaxial growth on epipolished sapphire is reported here for the first time. 相似文献
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Treatment of α-imino esters derived from glycine esters and benzophenone or benzaldehydes with potassium tert butoxide in DMSO gave persistent solutions of carbanions at 20?°C. The kinetics of their reactions with quinone methides and benzylidene malonates (reference electrophiles) have been followed photometrically under pseudo-first order conditions. The reactions followed second-order rate laws. Since addition of 18-crown-6 ether did not affect the reaction rates, the measured rate constants correspond to the reactions of the non-paired carbanions. Plots of the second-order rate constants against the electrophilicity parameters E of the electrophiles are linear, which allowed us to derive the nucleophile-specific parameters N and sN, according to the linear Gibbs energy relationship lg k2(20?°C)?=?sN(N + E). The Ph2C?=?N- and PhCH?=?N- groups act as very weak electron acceptors with the consequence that Ph2C?=?N-CH–-CO2R and PhCH?=?N-CH–-CO2R have a similar nucleophilicity as Ph-CH–-CO2Et, the anion of ethyl phenylacetate. 相似文献
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Alexander Kastner Isabella Poetsch Josef Mayr Jaroslav V. Burda Alexander Roller Petra Heffeter Bernhard K. Keppler Christian R. Kowol 《Angewandte Chemie (International ed. in English)》2019,58(22):7464-7469
Due to their high kinetic inertness and consequently reduced side reactions with biomolecules, PtIV complexes are considered to define the future of anticancer platinum drugs. The aqueous stability of a series of biscarboxylato PtIV complexes was studied under physiologically relevant conditions. Unexpectedly and in contrast to the current chemical understanding, especially oxaliplatin and satraplatin complexes underwent fast hydrolysis in equatorial position (even in cell culture medium and serum). Notably, the resulting hydrolysis products strongly differ in their reduction kinetics, a crucial parameter for the activation of PtIV drugs, which also changes the anticancer potential of the compounds in cell culture. The discovery that intact PtIV complexes can hydrolyze at equatorial position contradicts the dogma on the general kinetic inertness of PtIV compounds and needs to be considered in the screening and design for novel platinum‐based anticancer drugs. 相似文献
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Oliver Staller Christina Mitterbauer Katharina Mayr 《Central European Journal of Chemistry》2008,6(4):535-541
In this paper we report a method to determine tensile strengths and Young’s modulus of cubic biaxial textured metal tapes
used as substrate materials for coated conductors (CC). Simplicity, rapidity and reproducibility of the procedure are important
for the evaluation of continuous in-house productions. Our approach is based on the EN 10002-1 B tensile test method. A key
role for satisfactory results is the sample preparation of 100–250 μm thick tapes, which will be described in detail. Copper
(E-Cu57) can be successfully transformed to cubic biaxial textured substrates. Best results were achieved by annealing between
750°C and 850°C in reducing atmosphere. Best FWHM values for the ψ scan are 5.51° and for the ϕ scan are 4.5°. Pole figure
analysis verified the sharp {001} <100> texture of the tape. Vickers hardness measurements (HV 0.1) for the cold worked material
yielded values of 135 and for the annealed tape, values of 37. The ultimate tensile yield strength Rm of the textured substrate
is 150 MPa and thus significantly lower than that for the cold worked material (413 MPa). Cubic biaxial substrates could be
manufactured from Isotan CuNi44 (WM49) bars. Best results were achieved by annealing at 1200°C in reducing atmosphere. Pole
figure analysis verified the {001} <100> texture with other low intensity texture components. Vickers hardness measurements
(HV 0.1) for the cold worked material yielded values of 236 and for the annealed tape values of 92. The ultimate tensile yield
strength R
m of the textured substrate is 300 MPa and thus significantly lower than that for the cold worked material (723 MPa).
相似文献
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