Microstructure and Fe-vacancy ordering in the KFexSe2 superconducting system

Structural investigations by means of transmission electron microscopy (TEM) on KFexSe2 with 1.5 \leq x \leq 1.8 have revealed a rich variety of microstructure phenomena, the KFe1.5Se2 crystal often shows a superstructure modulation along the [310] zone-axis direction, this superstructure can be well interpreted by the Fe-vacancy order within the a-b plane. Increase of Fe-concentration in the KFexSe2 materials could not only result in the appearance of superconductivity but also yield clear alternations of microstructure. Structural inhomogeneity, the complex superstructures and defect structures in the superconducting KFe1.8Se2 sample have been investigated based on the high-resolution TEM.Comment: 13 pages, 4 figure

Extension of the Representative Elementary Watershed approach by incorporating energy balance equations

International audienceThe paper extends the Representative Elementary Watershed (REW) theory for cold regions by extending the energy balance equations to include associated processes and descriptions. A new definition of REW is presented which separates the REW into six surface sub-regions and two subsurface sub-regions. Soil ice, vegetation, vapor, snow and glacier ice are included in the system so that such phenomena as evaporation, transpiration, freezing and thawing can be modeled in a physically reasonable way. The final system of 24 ordinary differential equations (ODEs) can meet the requirement for most hydrological modeling applications, and the formulation procedure is re-arranged so that further inclusion of sub-regions and substances could be done more easily. The number of unknowns is more than the number of equations, which leads to the indeterminate system. Complementary equations are provided based on geometric relationships and constitutive relationships that represent geomorphological and hydrological characteristics of a watershed. Reggiani et al. (1999, 2000, 2001) and Lee et al. (2005b) have previously proposed sets of closure relationships for unknown mass and momentum exchange fluxes. The additional geometric and constitutive relationships required to close the new set of balance equations will be pursued in a subsequent paper

CFD Simulations on the Heating Capability in a Human Nasal Cavity

The air conditioning capability of the nose is dependent on the nasal mucosal temperature and the airflow dynamics caused by the airway geometry. A computational model of a human nasal cavity obtained through CT scans was produced and CFD techniques were applied to study the effects of morphological differences in the left and right nasal cavity on the airflow and heat transfer of inhaled air. A laminar steady flow of 10L/min was applied and two inhalation conditions were investigated: normal conditions, 25°C, 35% relative humidity and cold dry air conditions, 12°C, 13% relative humidity. It was found that the frontal regions of the nasal cavity exhibited greater secondary cross flows compared to the middle and back regions. The left cavity in the front region had a smaller cross-sectional area compared to the right which allowed greater heating as the heat source from the wall was closer to the bulk flow regions. Additionally it was found that the residence time of the inhaled air was important for the heating ability in laminar flows

Reversible Embedding to Covers Full of Boundaries

In reversible data embedding, to avoid overflow and underflow problem, before data embedding, boundary pixels are recorded as side information, which may be losslessly compressed. The existing algorithms often assume that a natural image has little boundary pixels so that the size of side information is small. Accordingly, a relatively high pure payload could be achieved. However, there actually may exist a lot of boundary pixels in a natural image, implying that, the size of side information could be very large. Therefore, when to directly use the existing algorithms, the pure embedding capacity may be not sufficient. In order to address this problem, in this paper, we present a new and efficient framework to reversible data embedding in images that have lots of boundary pixels. The core idea is to losslessly preprocess boundary pixels so that it can significantly reduce the side information. Experimental results have shown the superiority and applicability of our work