Design and analysis considerations for deployment mechanisms in a space environment

On the second flight of the INTELSAT V spacecraft the time required for successful deployment of the north solar array was longer than originally predicted. The south solar array deployed as predicted. As a result of the difference in deployment times a series of experiments was conducted to locate the cause of the difference. Deployment rate sensitivity to hinge friction and temperature levels was investigated. A digital computer simulation of the deployment was created to evaluate the effects of parameter changes on deployment. Hinge design was optimized for nominal solar array deployment time for future INTELSAT V satellites. The nominal deployment times of both solar arrays on the third flight of INTELSAT V confirms the validity of the simulation and design optimization

Spontaneous partitioning of the Ni + C 60 thin film grown at RT

a b s t r a c t We report on the pattern formation in the thin film of the Ni + C 60 mixture deposited on the MgO(0 0 1) substrate at room temperature (RT). Using magnetic force microscopy a periodic array of the magnetic domains has been revealed. The domains reflect hidden partitioning of the Ni + C 60 film (i.e., separated Ni-and C 60 -rich zones) that has not been observed by other applied methods. The effect indicates that even at RT, spontaneous separation of the Ni and C 60 phases may set in during the growth of the hybrid film. Thermal annealing (for 1 h at 500 • C) leads to dramatic rearrangement of the Ni + C 60 structure which (consequently) also results in the loss of the magnetic domain system. This phenomenon points out the thermodynamic instability of the as-prepared hybrid film that can (at elevated temperatures) trigger the process of the Ni and C 60 phase separation

Nanocrystalline Diamond Growth on Different Substrates

Thin nanocrystalline diamond (NCD) films were grown by microwave plasma chemical vapor deposition (MWCVD) on silicon wafers coated with polycrystalline diamond (PCD), cubic boron nitride and titanium nitride layers. A methane/ nitrogen mixture with a methane concentration of 17% was used as precursor, the substrate temperature was kept at 600oC, the working pressure was 38 mbar and the MW input power 1 kW. In the case of PCD and c-BN no pretreatment of the substrates was applied in order to deposit NCD, while no growth was observed on the TiN substrates without pretreatment in suspension of diamond powder (average grain size of 250 nm) in n-pentane which enhanced the diamond nucleation. The morphology of the films was studied by scanning electron microscopy (SEM) which revealed closed and uniform layers. The results from X-ray diffraction (XRD) showed that all films were composed of diamond crystallites with grain sizes of 3-5 nm. The Raman spectra of NCD were similar indicating that the substrate has no substantial influence of the bonding structure of the films. The mechanical properties of the films were also investigated. It was found that the hardness and the Young's modulus of NCD on PCD and c-BN determined by nanoindentations were higher than those of NCD on TiN due to the influence of the nature of the substrate. In contrary, the best adhesion was observed for the latter films most probably as a result of the better adhesion between the silicon substrate and the intermediate layers.JRC.I.4-Nanotechnology and Molecular Imagin

V.: Regionally-selective adhesion and growth of human osteoblast-like MG 63 cells on micropatterned fullerene C60 layers

Fullerenes C60 were deposited on to microscopic glass coverslips using the Leybold Univex-300 vacuum system through metallic masks with rectangle openings. Below the openings, the C60 formed prominences 128 ± 8 nm (A), 238 ± 3 nm (B), 326 ± 5 nm (C) or 1043 ± 57 nm (D) in height. Human osteoblast-like MG 63 cells in the cultures on samples A, B and C were distributed almost homogeneously, while on samples D, they were localized almost exclusively in the grooves among the prominences. Thus, fullerene C60 films can act as substrates for guided cell adhesion and growth

Структурні та механічні властивості аморфних і полікристалічних плівок B₄C

Магнетронним розпиленням мішені B₄C виготовлено аморфні та кристалічні плівки. Досліджено їхній склад, твердість, модуль пружності, внутрішні напругий структуру залежно від зміщення на підкладці та її температури.Магнетронным распылением мишени B₄C приготовлены аморфные и кристаллические пленки. Исследовали их состав, твердость, модуль упругости, внутренние напряжения и структуру в зависимости от смещения на подложке иее температуры.Amorphous and crystalline B₄C films were prepared by magnetron sputtering. Film composition, hardness, elastic module, internal tensions and structure were studded depending on substrate bias and substrate temperature (TS). It was established that hardness and elastic module decreas