102 research outputs found
Studies in the organonitrogen chemistry of tin and neighbouring elements
This thesis describes the preparation and properties of some new organonitrogen derivatives of silicon, germanium, and tin. The structural implications of their I.R., (^1)H-NMR. , and mass spectra are discussed with X-ray crystal structures in some cases. A survey of species containing tin-nitrogen bonds, and a discussion of the stereochemistry of tin are also presented. New methyleneamine derivatives of the type (R(_2)CN)(_n)Sn(^IV)C1(_4-n)(n = 2-4), (Ph(_2)CN)(_2)GeC1(_2), [(R(_2)CN)(_2)Sn(^11)](_n),(Ph(_2) CNSn(^11)c1)(_2), and Li(^t)Bu(_2)CN)(_3)Sn(^11) were prepared from the metal chlorides and N-lithioketimines. The adducts Ph(_2)CNH.Sn(^11)Cl(_2), ((^t)Bu(_2)CNH)(_n)Sn(^IV)Cl(_4) (n = 1,2), Ph(_2)CNH. (Ph(_2)CNSn(^11)Cl)(_2). C(_7)H(_8), and (^t)Bu(_2)CNH. (^t)Bu(_2)CNSn(^11)(_2)C1(_3) are described. Attempts to prepare (^t)Bu(_2)CNSn(^IV) led to (^t)BuCN and Sn(^11)Cl(_2). Similar decomposition of ((^t)Bu(_2)CN)(_n)Sn(^IV)c1(_4-n) (n = 2,3) 2,3) led to the imino-tin(II) complexes (^t)Bu(_2)CNH. (^t)Bu(_2)CNSn(_2)(^11)Cl(_3) and (^t)Bu(_2)CNH(_2)(^+). ((^t)Bu(_2)Sn(_3)(^11)C1(_5)(^-). The new M(^IV) derivatives are monomeric, except for the iminotin chlorides [(ph(_2)CN)(_n)Sn(^IV)C1(_4-n)](_m)(n = 2,3; m ≥ 2). The Sn(^11) derivatives are mostly di- or oligomeric, containing three-coordinate tin. Association appears to involve bridging methyleneamino groups. The adducts R(_2)CNH. (R(_2)CN)(_n)Sn(_2)(^11)C1(_4-n) to contain one three-coordinate and one four- coordinate tin atom. The C=N-M skeletons of those compounds containing terminal methyleneamino groups are probably bent with little or no N→M (p→d) π-bonding
Atomic scale investigation of Cr precipitation in copper
The early stage of the chromium precipitation in copper was analyzed at the
atomic scale by Atom Probe Tomography (APT). Quantitative data about the
precipitate size, 3D shape, density, composition and volume fraction were
obtained in a Cu-1Cr-0.1Zr (wt.%) commercial alloy aged at 713K. Surprisingly,
nanoscaled precipitates exhibit various shapes (spherical, plates and
ellipsoid) and contain a large amount of Cu (up to 50%), in contradiction with
the equilibrium Cu-Cr phase diagram. APT data also show that some impurities
(Fe) may segregate along Cu/Cr interfaces. The concomitant evolution of the
precipitate shape and composition as a function of the aging time is discussed.
A special emphasis is given on the competition between interfacial and elastic
energy and on the role of Fe segregation
Microscopic modelling of simultaneous two-phase precipitation: application to carbide precipitation in low-carbon steels
Simulation of Cu Precipitation in Fe-Cu Dilute Alloys with Cluster Mobility
Cu-rich precipitates formation is associated with the precipitation hardening of Fe-Cu based steels and the embrittlement of reactor pressure vessel steels under neutron irradiation. The accurate modeling of the time evolution of Cu-rich precipitates is therefore of fundamental importance for the design of Fe-Cu based steels and the prediction of the irradiation induced shift of the ductile to brittle transition temperature of reactor pressure vessels. This work applies cluster dynamics with mobile Cu monomers and clusters to model Cu precipitation in dilute Fe-Cu alloys at several temperatures. Optimized model parameters can be used to simulate the mean radius, number density, volume fraction, and matrix composition evolution during isothermal annealing with reasonable accuracy. The possible reduction of the mobility of Cu-rich clusters due to additional alloying elements in Fe-Cu based steels is discussed
A study of copper precipitation in Fe-Cu and Fe-Cu-Ni model alloys
SIGLEAvailable from British Library Document Supply Centre- DSC:D175441 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Per IMERSLUND: Un voluntario noruego en la Guerra Civil española, edición a cargo de Mariano González Campo, Madrid, SND Editores, 2020, 224 pp., ISBN: 9788412212532
Reseña de la obra de Per IMERSLUND: Un voluntario noruego en la Guerra Civil española, edición a cargo de Mariano González Campo, Madrid, SND Editores, 2020, 224 pp., ISBN: 9788412212532
TRANSMISSION ELECTRON-MICROSCOPE INVESTIGATIONS OF THE STRUCTURE OF COPPER PRECIPITATES IN THERMALLY-AGED FE-CU AND FE-CU-NI
HIGH-RESOLUTION ELECTRON-MICROSCOPY STUDIES OF THE STRUCTURE OF CU PRECIPITATES IN ALPHA-FE
TRANSMISSION ELECTRON MICROSCOPE INVESTIGATIONS OF 9R MARTENSITE FORMATION IN COPPER PRECIPITATES IN THERMALLY AGED IRON-COPPER ALLOYS
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