[en] In current work we perform molecular dynamics simulations to investigate the growth of Al thin film on Cu substrate through physical vapor deposition. The effects of incident angle on the morphology and the formed internal microstructures of Al thin films are emphasized. Simulation results show that Al thin films grow in the epitaxy growth mode of layer-by-layer fashion under incident energy of 0.1 eV. Further analysis of the internal microstructures demonstrates the formation of twin boundaries in Al thin films. It is found that the morphology of the island-like clusters formed in Al thin films varies significantly upon incident angle. The compositions of atoms of different lattice structures strongly depend on incident angle, which consequently affects the propensity of different internal microstructures formed in Al thin films. - Highlights: ► Growth of Al thin film on Cu substrate is studied by molecular dynamics simulations. ► Geometry of island-like cluster is affected significantly by incident angle. ► Internal microstructure of Al thin film strongly depends on incident angle

[en] The [³H]XTPs are used widely to monitor RNA synthesis in vitro. Recently, the authors discovered that they reflected only 40-45% of the true rate of nuclear RNA synthesis. Thus, when [8-¹⁴C]GTP was used, 1466 pmol [8-¹⁴C]GMP was incorporated per mg DNA/10 min. On the other hand, when [8-³H]GTP was used, only 564 pmol [8-³H]GMP was incorporated per mg DNA/10 min. There are three obvious factors that could have contributed to this greater than 2-fold difference in the apparent incorporation rate, none of which, the authors are able to conclude, are contributing factors. The data also show that the ³H label was removed after it was incorporated into RNA. Similar differences were observed when ³H and ¹⁴C labeled pairs of ATP, UTP and CTP were compared. Furthermore, when nuclei were fractionated into nucleolar and nucleoplasmic fractions and carried out RNA synthesis, the loss of ³H label was observed mainly from the nucleoplasmic fraction. (Auth.)

[en] HIGHLIGHTS• Reflectivity of aluminum alloy is improved after being coated by gold film. • The optimal parameters combination of gold film are 45°C, 0.35 A, 140 s. • Adhesive force of gold film would be changed after holding at 60, −20°C. Aluminum alloys are widely applied in optical turrets after coating and super-finishing. Gold films prepared on aluminum alloy substrates via electron beam (e-beam) evaporation are considered to be effective way to realize close to total reflection of incident light. Here, we investigated the optimization of the reflectivity parameters of e-beam evaporated gold films; then, the influence of different deposition parameters on the surface quality, adhesive force and reflectivity (incident light in the 650–1700 nm range) of the film at −20, 25 and 60°C were systematically studied. The results demonstrated that the reflectivity and adhesion of the gold films both increased after high temperature holding and decreased slightly after low temperature holding. However, the surface morphology of the gold film did not change substantially. After holding at 60 and −20°C, the adhesive force decreased, which indicated that the adhesion strength between the reflective membrane and the substrate decreased.

[en] In order to improve the lubrication of movement mechanism in final optics assembly, the plasma immersion ion implantation (PIII) technology is used to modify mechanical properties of work pieces with complex shape. The combination of suitable parameters can largely increase the hardness and wear resistance of material surfaces. The verification test was made by modifying the mechanical properties of the bearing inner race and bearing outer ring. Furthermore, the dimensional accuracy and the surface roughness of sample work pieces modified by PIII technology can maintain consistence with those of untreated pieces. The work sufficiently certificates that the PIII technology can amend the mechanical properties of work pieces and elongate the life length of movement mechanism kinematic accuracy. (authors)

[en] In this paper we report molecular dynamics based atomistic simulations of deposition process of Al atoms onto Cu substrate and following nanoindentation process on that nanostructured material. Effects of incident energy on the morphology of deposited thin film and mechanical property of this nanostructured material are emphasized. The results reveal that the morphology of growing film is layer-by-layer-like at incident energy of 0.1-10 eV. The epitaxy mode of film growth is observed at incident energy below 1 eV, but film-mixing mode commences when incident energy increase to 10 eV accompanying with increased disorder of film structure, which improves quality of deposited thin film. Following indentation studies indicate deposited thin films pose lower stiffness than single crystal Al due to considerable amount of defects existed in them, but Cu substrate is strengthened by the interface generated from lattice mismatch between deposited Al thin film and Cu substrate.