On the Benign One-Pot Preparation of Nanoporous Copper Thin Films with Bimodal Chan-nel Size Distributions by Chemical Dealloying in an Alkaline Solution

Nanoporous copper (NPC) thin films with bimodal channel size distributions can be benignly fabricated by one-pot chemical dealloying of dual-phase Al 27 at Cu alloy with hypereutectic structure in the NaOH solution. The microstructure of these NPC thin films was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis. The results show that these NPC thin films are composed of interconnected large-sized channels (100s of nm) with highly porous channel walls (10s of nm), in which large-sized channels resulting from entire dissolution of solid solution while small-sized those de-riving from part corrosion of intermetallics. Both large- and small-sized channels are 3D, open, and bicon-tinuous. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520

Preparation of Nanostructured Li2MnO3 Cathode Materials by Single-Step Hydrothermal Method

Nanosized (10~50 nm) cathode material Li2MnO3 was prepared for with MnSO4·H2O，KMnO4 and Li- OH aqueous solution as the precursor via single-step hydrothermal reaction by controlling the reaction time, proportion of processor, and the reagent concentration. The prepared materials were well crystallized and exhibited a monoclinic Li2MnO3 structure with a space group of C2/m phase. The electrochemical performance of the material was tested at current density of 60 mAg-1 (1/4 C) between 4.3V and 2.0 V at room temperature, showing good electrochemical properties with the initial discharge capacity of 243 mAh·g-1, because it was more exposed to the electrolyte due to its nanostructure. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519

Structure and Electrochemical Performance of Li[Li0.2Co0.4Mn0.4]O2 Cathode Material for Lithium Ion Battery by Co-precipitation Method

The nano-structured Li[Li0.2Co0.4Mn0.4]O2 cathode material is synthesized by a co-precipitation method. X-ray diffraction shows that the synthesized material has a hexagonal α-NaFeO2 type structure with a space group R-3m. Scanning electron microscopy and transmission electron microscopy images show the homogeneous distribution with 100-200 nm. X-ray photoelectron spectroscopy results indicate that the oxi-dation states of Co and Mn in Li[Li0.2Co0.4Mn0.4]O2 are present in trivalence and tetravalence, respectively. The charge-discharge curves and cycling performance are analyzed in detail. The initial charge and dis-charge capacities are respectively 236.5 mAh g-1 and 140.3 mAh g-1 at the current density of 100 mA g-1 in the voltage range of 2.0-4.6 V. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520

Water discharge and sediment flux changes over the past decades in the Lower Mekong River: Possible impacts of the Chinese dams

Hydrology and Earth System Sciences102181-19

Attribution of climate change, vegetation restoration, and engineering measures to the reduction of suspended sediment in the Kejie catchment, southwest China

10.5194/hess-18-1979-2014Hydrology and Earth System Sciences1851979-199

Subsidence and carbon loss in drained tropical peatlands

Biogeosciences931053-107

Rapid channel incision of the lower Pearl River (China) since the 1990s as a consequence of sediment depletion

Hydrology and Earth System Sciences1161897-190

Numerical evaluation of flow regime changes induced by the Three Gorges Dam in the Middle Yangtze

The full operation of the Three Gorges Dam (TGD) has altered the downstream natural flow regime. Flow regime changes have resulted in profound influences on the utility of water resources and hence a large area with a riparian ecosystem including China's two largest freshwater lakes in the Middle Yangtze. Because of complicated flow regimes in this large-scale river–lake system, the TGD's impacts on flow regimes are highly heterogeneous and require to be carefully addressed. To better understand them, we estimated water level and discharge changes solely induced by the TGD from 2006 to 2011 using a hydrodynamic model that facilitates the separation of the TGD's contribution to flow regimes. Results indicated that water regulation of the TGD caused profound impacts on the flow regimes of the Middle Yangtze. In the impoundment period from mid-September to October, rapid and significant decline of the water discharge downstream the TGD produced a prolonged dry season that occurred around 10 days earlier than before. Our analysis elucidated a pattern of recent changes in the flow regimes caused by the TGD. The findings are useful for addressing the TGD-induced environmental issues, optimizing the TGD's operation, and generating adaptive management strategy for the complex river–lake ecosystem

Charge ordering in charge-compensated Na0.41CoO2Na_{0.41}CoO_2 by oxonium ions

Charge ordering behavior is observed in the crystal prepared through the immersion of the $Na_{0.41}CoO_2$ crystal in distilled water. Discovery of the charge ordering in the crystal with Na content less than 0.5 indicates that the immersion in water brings about the reduction of the $Na_{0.41}CoO_2$. The formal valence of Co changes from +3.59 estimated from the Na content to +3.5, the same as that in $Na_{0.5}CoO_2$. The charge compensation is confirmed to arise from the intercalation of the oxonium ions as occurred in the superconducting sodium cobalt oxide bilayer-hydrate.\cite{takada1} The charge ordering is the same as that observed in $Na_{0.5}CoO_2$. It suggests that the Co valence of +3.5 is necessary for the charge ordering.Comment: 5 pages, 4 figure

Surface structure and solidification morphology of aluminum nanoclusters

Classical molecular dynamics simulation with embedded atom method potential had been performed to investigate the surface structure and solidification morphology of aluminum nanoclusters Aln (n = 256, 604, 1220 and 2048). It is found that Al cluster surfaces are comprised of (111) and (001) crystal planes. (110) crystal plane is not found on Al cluster surfaces in our simulation. On the surfaces of smaller Al clusters (n = 256 and 604), (111) crystal planes are dominant. On larger Al clusters (n = 1220 and 2048), (111) planes are still dominant but (001) planes can not be neglected. Atomic density on cluster (111)/(001) surface is smaller/larger than the corresponding value on bulk surface. Computational analysis on total surface area and surface energies indicates that the total surface energy of an ideal Al nanocluster has the minimum value when (001) planes occupy 25% of the total surface area. We predict that a melted Al cluster will be a truncated octahedron after equilibrium solidification.Comment: 22 pages, 6 figures, 34 reference