| 1. |
- Gauthier, Y., et al.
(author)
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Surface structure and composition of the missing-row reconstruction of VC0.8(1 1 0) : A LEED, GIXRD and photoemission study
- 2007
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In: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 601:16, s. 3383-3394
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Journal article (peer-reviewed)abstract
- Low energy electron diffraction, grazing incidence X-ray diffraction and photoemission were used to decipher the detailed structural arrangement and chemical composition of the surface region of a transition metal carbide, VC0.8(1 1 0). In agreement with previous scanning tunneling microscopy (STM) studies, we find that the surface reconstructs with a ridge-and-valley grating structure along the [1 over(1, ¯) 0] direction resulting from {0 0 1} faceting for the (3 × 1) and the (4 × 1) phases. Both superstructures terminate on the vacuum side with a nearly stoïchiometric VC region due to C segregation, in contrast with the conclusions drawn from this previous STM study. However, the present experiments clearly show that these phases are metastable, and slow cooling results in a (1 × 1) surface, which is highly C depleted, similarly to the (1 0 0) face. © 2007 Elsevier B.V. All rights reserved.
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| 2. |
- Langlais, B., et al.
(author)
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Mars environment and magnetic orbiter model payload
- 2009
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In: Experimental astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 23:3, s. 761-783
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Journal article (peer-reviewed)abstract
- Mars Environment and Magnetic Orbiter was proposed as an answer to the Cosmic Vision Call of Opportunity as a M-class mission. The MEMO mission is designed to study the strong interconnections between the planetary interior, atmosphere and solar conditions essential to understand planetary evolution, the appearance of life and its sustainability. MEMO provides a high-resolution, complete, mapping of the magnetic field (below an altitude of about 250 km), with an yet unachieved full global coverage. This is combined with an in situ characterization of the high atmosphere and remote sensing of the middle and lower atmospheres, with an unmatched accuracy. These measurements are completed by an improved detection of the gravity field signatures associated with carbon dioxide cycle and to the tidal deformation. In addition the solar wind, solar EUV/UV and energetic particle fluxes are simultaneously and continuously monitored. The challenging scientific objectives of the MEMO mission proposal are fulfilled with the appropriate scientific instruments and orbit strategy. MEMO is composed of a main platform, placed on a elliptical (130 x 1,000 km), non polar (77A degrees inclination) orbit, and of an independent, higher apoapsis (10,000 km) and low periapsis (300 km) micro-satellite. These orbital parameters are designed so that the scientific return of MEMO is maximized, in terms of measurement altitude, local time, season and geographical coverage. MEMO carry several suites of instruments, made of an 'exospheric-upper atmosphere' package, a 'magnetic field' package, and a 'low-middle atmosphere' package. Nominal mission duration is one Martian year.
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