In this work, we studied an atomic layer deposition (ALD) process of ZrO2 with the precursors of tetrakis(dimethylamido)zirconium(IV) and water. We investigated the growth characteristics and mechanism of the ALD ZrO2 in the temperature range of 50–275 °C. Furthermore, the evolutions of film thickness and morphology were studied and discussed. It was found that the growth rate of ZrO2 decreased almost linearly with the increasing temperature from ∼1.81 Å/cycle at 50 °C to ∼0.8 Å/cycle at 225 °C. Interestingly, it was revealed that the growth of ZrO2 films ceased after a certain number of ALD cycles at a temperature higher than 250 °C. We also verified that the crystallinity of ZrO2 evolved with deposition temperature from amorphous to crystalline phase. In addition, the wettability of ZrO2 films was studied, showing a hydrophobic nature.

Graphitic carbon nitride (g-C3N4) microspheres (CNMS) were fabricated via a solvothermal method by using dicyandiamide and cyanuric chloride as precursors. The morphology, band structure, and defects can be simultaneously regulated by merely adjusting the concentration of precursors. Structural characterization results indicate that all the prepared samples possess spherical morphology, while the band gap decreased as the precursor concentration increased from 8 mmol (CNMS-1) to 24 mmol (CNMS-3). Besides, ultraviolet photoelectron spectroscopy results suggested that the valence band of CNMS-2 (16 mmol) was much higher than that of CNMS-1 and CNMS-3. Additionally, organic elemental analysis, X-ray photoelectron spectroscopy, and electron paramagnetic resonance results unveil the formation of nitrogen defects on the surface of prepared samples. Besides, CNMS-2 exhibits an enhanced apparent reaction rate constant of RhB degradation than that of CNMS-1 and CNMS-3. The improved apparent reaction rate constant may be due to the lowered valence band as well as the formation of nitrogen defects. This work might guide the regulation of the morphology and band structure of g-C3N4-based materials prepared via the one-pot hydrothermal method.

Recent studies have shown that chemical immiscibility is important to achieve enhanced radiation tolerance in metallic multilayers as immiscible layer interfaces are more stable against radiation induced mixing than miscible interfaces. However, as most of these immiscible systems have incoherent interfaces, the influence of coherency on radiation resistance of immiscible systems remains poorly understood. Here, we report on radiation response of immiscible Cu/Fe multilayers, with individual layer thickness h varying from 0.75 to 100 nm, subjected to He ion irradiation. When interface is incoherent, the peak bubble density decreases with decreasing h and reaches a minimum when h is 5 nm. At even smaller h when interface is increasingly coherent, the peak bubble density increases again. However, void swelling in coherent multilayers with smaller h remains less than those in incoherent multilayers. Our study suggests that the coherent immiscible interface is also effective to alleviate radiation induced damage.

A systematic x-ray diffraction (XRD) study was performed on room-temperature Xe-irradiated and postirradiation annealed CeO2. Large scale XRD did not show any additional irradiation-induced phases upon irradiation. Depth profiling the CeO2 (111) diffraction peak over the 150 nm deep Xe-irradiated layer (400 keV, 1 × 1020 Xe/m2) by grazing incidence XRD indicated a lattice expansion at the irradiated layer. Postirradiation annealing (1 h at 1000 °C) in an oxygen-containing environment removed the observed XRD features. Electron energy loss spectroscopy (EELS) was performed for cross-sectional samples before and after postirradiation annealing. EELS showed that the Ce charge state changed from +4 to +3 at the CeO2 surface indicating the presence of O vacancies in both as-irradiated and annealed samples. EELS also indicated that the amount of O vacancies was reduced at the irradiated region by annealing. The experimental results are discussed based on electronic properties of CeO2, annihilation of oxygen vacancies, and evolution of irradiation damage.

Oxide composites are a class of materials with potential uses for nuclear, space, and coating applications. Exploiting their promise, however, requires a detailed understanding of their interfacial structure and chemistry. Using analytical microscopy, we have examined the radiation damage behavior at the interface of a model oxide bilayer, SrTiO3/MgO. The as-synthesized SrTiO3 thin film contained both (100) and (110) oriented domains. We found that after ion beam implantation the (110) domains amorphized at a lower radiation fluence than the (100) domains. Further, a persistent crystalline layer of SrTiO3 forms at the interface even as the rest of the SrTiO3 film amorphizes. We hypothesize that the enhanced amorphization susceptibility of the (110) domains is a consequence of how charged irradiation-induced defects at the interfaces interact with the charged planes of the (110) domains. These results demonstrate the complex relationship between interfacial structure and radiation damage evolution at oxide interfaces.

The irradiation damage behaviors of single crystal (SC), coarse-grained (CG), and nanograined (NG) copper (Cu) films were investigated under Helium (He) ion implantation at 450 °C with different ion fluences. In irradiated SC films, plenty of cavities are nucleated, and some of them preferentially formed on growth defects or dislocation lines. In the irradiated CG Cu, cavities formed both in grain interior and along grain boundaries; obvious void-denuded zones can be identified near grain boundaries. In contrast, irradiation-induced cavities in NG Cu were observed mainly gathering along grain boundaries with much less cavities in the grain interiors. The grains in irradiated NG Cu are significantly coarsened. The number density and average radius of cavities in NG Cu was smaller than that in irradiated SC Cu and CG Cu. These experiments indicate that grain boundaries are efficient sinks for irradiation-induced vacancies and highlight the important role of reducing grain size in suppressing radiation-induced void swelling.

Quality control of the inertial confinement fusion (ICF) target in the laser fusion program is vital to ensure that energy deposition from the lasers results in uniform compression and minimization of Rayleigh–Taylor instabilities. The technique of nuclear microscopy with ion beam analysis is a powerful method to provide characterization of ICF targets. Distribution of elements, depth profile, and density image of ICF targets can be identified by particle-induced X-ray emission, Rutherford backscattering spectrometry, and scanning transmission ion microscopy. We present examples of ICF target characterization by nuclear microscopy at Fudan University in order to demonstrate their potential impact in assessing target fabrication processes.

Small-scale testing techniques such as nanoindentation and micro-/nanocompression are promising methods for addressing mechanical properties of ion-beam-irradiated materials. We performed different proton irradiations and critically evaluated the results obtained from nanoindentation and pillar compression, both performed parallel and perpendicular to the irradiation direction. Experiments parallel to beam direction suffer from variation of material properties with penetration depth. This is improved by cross-sectional experiments, thereby probing the effect of different doses along the beam penetration depth on mechanical properties. Finally, we demonstrate that, compared with nanoindentation, miniaturized uniaxial compression experiments offer a more reliable and straightforward interpretation of the mechanical data, as they impose a nominally uniaxial stress on a well-defined volume at a specific position. Moreover, the exposed pillar geometry is not influenced by surface contamination and enables in situ observation of the governing mechanical processes, which is typically not possible during indentation experiments in a half-space geometry.

In 2008 January the 24th Chinese expedition team successfully deployed the Chinese Small Telescope ARray (CSTAR) to Dome A, the highest point on the Antarctic plateau. CSTAR consists of four 14.5cm optical telescopes, each with a different filter (g, r, i and open) and has a 4.5°×4.5° field of view (FOV). Based on the CSTAR data, initial statistics of astronomical observational site quality and light curves of variable objects were obtained. To reach higher photometric quality, we are continuing to work to overcome the effects of uneven cirrus cloud cirrus, optical “ghosts” and intra-pixel sensitivity. The snow surface stability is also tested for further astronomical observational instrument and for glaciology studies.

During the mid-Holocene the eastern Taihu area, on China's Yangtze delta plain, was populated by advanced late Neolithic cultures supported by intensive domesticated rice cultivation. This agricultural system collapsed around 4200 cal yr BP, with severe population decline, the end of the Liangzhu culture, and about half a millennium of very low-scale human activity in the area before the re-establishment of agricultural production. Microfossil analyses from six sedimentary sequences, supported by AMS 14C dating, has allowed reconstruction of mid-Holocene hydrological conditions and salinity changes which would have had a major influence on agricultural viability and cultural history in the coastal wetlands. These data, allied to existing stratigraphic and sea-level records, show that chenier ridges that developed after ca. 7000 cal yr BP in the east of the area sheltered it from marine inundation and although still connected to the sea through tidal creeks, low-salinity conditions persisted throughout the Neolithic period. There is no evidence that marine flooding caused the collapse of Liangzhu culture. Marine influence was stable and evolved slowly. Social and cultural causes may also have been important, but if environmental change triggered the collapse of Neolithic agricultural society here, other natural forces must be sought to explain this event.

Polycrystalline δ-phase Sc4Zr3O12 was irradiated with 200 keV Ne+ ions at cryogenic temperature to fluences ranging from 2 × 1018 to 1 × 1021 Ne/m2. Irradiation-induced structural evolution was examined by using grazing incidence x-ray diffraction and cross-sectional transmission electron microscopy. An order-to-disorder (O-D) crystal structure transformation (from an ordered δ-phase to a disordered, fluorite phase) was observed to initiate by a fluence of 2 × 1018 Ne/m2, corresponding to a peak ballistic damage dose of ∼0.075 displacements per atom. This displacement damage dose is much lower than the O-D transformation dose threshold found in previous heavy ion irradiation experiments on δ-Sc4Zr3O12 [J.A. Valdez et al., Nucl. Instrum. Methods B250, 148 (2006); K.E. Sickafus et al., Nat. Mater.6, 217 (2007)]. In this study, we contrast the O-D transformation efficiency of the light Ne ions used in these experiments, to the heavy (Kr) ions used previously, and interpret the differences in terms of enhanced damage efficiency for light ions (greater fraction of surviving defects per defect produced). To better quantify this surviving defect phenomenon, we also present new, additional ion irradiation results on δ-Sc4Zr3O12, obtained from 300 keV Kr2+ and 100 keV He+ ion irradiation experiments.