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| 3. |
- Reineck, Ingrid, et al.
(författare)
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High-resolution UV photoelectron spectrum of CO2
- 1983
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Ingår i: Chemical Physics. - : Elsevier BV. - 0301-0104. ; 78:3, s. 311-318
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Tidskriftsartikel (refereegranskat)abstract
- The highly-resolved HeI photoelectron spectrum of CO2 is presented and its vibrational structure studied in detail. In the 2Πg ionic state the v3 antisymmetric mode is found to be excited in double quanta (v1- v2- v3 = 0. 0. 2) with energy hv3 = 181 meV. In the 2Σg+ state a single quantum of the same mode is found to be excited (hv3 = 189 meV) in combination with a v1 excitation. Vibronic interaction with vibrational levels in the 2Σu+ state of the ion is suggested to promote this (1, 0, 1) excitation. It is established that inelastic scattering processes contribute to the vibrational structure in the 2Σg+ band. The spin-orbit splitting in the 2Πg is determined to be 19±1 meV and 10±2 eV in the 2Πu state. Vibronic structure is resolved in the 2Πg band where the Renner-Teller coupling constant is determined to be ε = 0.21±0.02 and the vibrational energy of the v2 mode as 60±7 meV. In the 2Πu state the v2 energy is found to be hv2 = 60 meV from the observed hot-band structure.
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| 4. |
- Reineck, Ingrid, et al.
(författare)
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Inelastic scattering and satellite fine structure in the high-resolution uv photoelectron spectrum of CS2
- 1984
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Ingår i: Journal of Electron Spectroscopy and Related Phenomena. - : Elsevier BV. - 0368-2048. ; 34:3, s. 235-252
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Tidskriftsartikel (refereegranskat)abstract
- The outer valence region in CS2 has been studied by high-resolution UV photpelectron Spectroscopy. The spectra reveal detailed vibrational structure in the X 2Πg, A 2Πu, B 2Σ+u and C 2Σ+g bands. Some of the fine-structure peaks in the X B and C bands are shown to be pressure-dependent. The reason for the pressure dependence is assumed to be inelastic scattering of electrons emitted in the adiabatic transitions. It is established that the two CI satellite bands present in the He(I)-excited spectrum contain vibrational structure.
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| 6. |
- Trinh, David, 1981-, et al.
(författare)
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Coated Insert
- 2006
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Patent (populärvet., debatt m.m.)
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| 7. |
- Trinh, David Huy, 1981-
(författare)
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Nanocrystalline Alumina-Zirconia Thin Films Grown by Magnetron Sputtering
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Alumina-zirconia thin films have been deposited using dual magnetron sputtering. Film growth was performed at relatively low-to-medium temperatures, ranging from ~300°C to 810 °C. Different substrates were applied, including silicon (100), and industrially relevant materials, such as WC-Co hardmetal. Both radio-frequency sputtering and direct-current magnetron sputtering were utilised to achieve a range of film compositions. The influence of sputtering target was investigated; both ceramics and metals were used as sputtering sources. Microstructural characterisation was performed with a range of electron microscopy and x-ray diffraction techniques which show that the pure zirconia was deposited in the monoclinic phase. Reduced mobility of depositing species, as in the case of direct-current sputtering, yielded preferred crystallographic orientation in the {100} directions. The initial nucleation layer consisted of the metastable tetragonal zirconia phase. This phase could be grown over film thicknesses ~1 μm through the addition of ~3 at.% Al under similar low mobility conditions. For cases of higher mobility, as obtained through radio-frequency sputtering, the metastable cubic zirconia phase formed in the film bulk for alumina-zirconia nanocomposites. A combination of two mechanisms is suggested for the stabilisation of metastable zirconia phases: oxygen-deficiency and aluminium segregations with resultant restraint on the zirconia lattice. The sputter deposition process was investigated through energy resolved mass spectrometry in the case of radio-frequency sputtering; the sputter deposition flux contained a mixture of metallic ions, metaloxygen clusters, and oxygen ions. The presence of metal-oxygen clusters was found to be important in oxygen-stoichiometry and thus the phase selection of the resultant film. The energy distributions were similar when comparing sputtering from ceramic and metallic targets. A mass-balance model has also been developed for the transport phenomena and reactions of particles in reactive sputtering of two targets in a two-gas scenario for the alumina-zirconia system. Addition of nitrogen to the working gas was found to eliminate the hysteresis in the target poisoning for oxygen reactive sputtering. The higher reactivity of oxygen contributed to a higher oxygen content in resultant films compared to the oxygen content in the oxy-nitride working gas. The model was thus shown to be successful for tuning depositions in the alumina-zirconia oxy-nitride system.
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| 8. |
- Östberg, Gustaf, 1971, et al.
(författare)
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Effect of TaC on plastic deformation of WC-Co and Ti(C,N)-WC-Co
- 2006
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Ingår i: International Journal of Refractory Metals and Hard Materials. - : Elsevier BV. - 0263-4368. ; 24:1-2, s. 145-154
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Tidskriftsartikel (refereegranskat)abstract
- The plastic deformation resistance of metal cutting inserts made from a WC–Co cemented carbide, a Ti(C, N)–WC–Co cermet and corresponding materials with additions of TaC has been studied. The cermets were produced with both high and low carbon activity, resulting in a total of six materials. Ab initio calculations of some WC/WC grain boundary geometries suggest that both Co and Ta segregate substitutionally to the boundary and improve the grain boundary strength when substituting carbon. However, only Co segregation was found experimentally, probably due to (Ta, W)C formation. Plastic deformation tests were performed with a turning operation under controlled conditions. For the WC–Co, the addition of Ta had a positive effect for lower cutting speeds but at higher speeds the effect was negative. Three-point bending tests indicated a beneficial effect of Ta in WC–Co, which was also confirmed by internal friction (IF) measurements. However, after thermal cycling, the effect of Ta could be smaller, or even negative. The Ta cermet produced with low carbon activity exhibited a better plastic deformation resistance during cutting but no apparent effects of Ta could be seen either in IF measurements or in three-point bending tests of the cermets. However, a correlation was found between plastic deformation during turning and IF spectra. In the cermet materials, binder phase lamella formation promotes grain boundary sliding at high temperatures.
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| 9. |
- Östberg, Gustaf, 1971, et al.
(författare)
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Mechanisms of plastic deformation of WC-Co and Ti(C,N)-WC-Co
- 2006
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Ingår i: Int. J. Refract. Hard Mater.. - : Elsevier BV. - 0263-4368. ; 24:1-2, s. 135-144
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Tidskriftsartikel (refereegranskat)abstract
- The deformation of the cutting edge of inserts made from WC–Co and Ti(C, N)–19%WC–Co upon radial turning was measured as a function of the cutting speed. Ab initio calculations of some grain boundary geometries in WC–Co indicated that Co segregates to WC/WC grain boundaries in submonolayer proportions and increases their strength and resistance to Co infiltration. This was also confirmed with TEM-EDX. SEM studies showed that during plastic deformation the hard phase skeletons in both materials were partly broken up and infiltrated by binder phase. TEM observations showed a considerable deformation of the WC grains and some infiltrated grain boundaries were facetted along low energy planes. In the cermet, no deformation of the hard phase grains could be seen. The plastic deformation at high temperatures observed by three-point bending corresponds to a number of relaxation processes, detected by internal friction, related to grain boundary sliding. Both materials deform by grain boundary sliding, accommodated in the cermet by Co diffusion and in the WC–Co by deformation of the hard phase and diffusion of Co.
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