Papers by Keyword: Scale Structure

Abstract: Photonic crystals are periodic dielectric nanocomposites, which have photonic band gaps that forbid the propagation of light within certain frequency ranges. This property enables one to manipulate light with amazing facility. Such nanoarchitectures frequently occur in living organism like butterflies and beetles. Butterfly scales are particularly well suited to be used as optical gas sensors as their nanoarchitecture is an open sponge-like type, composed of chitin and air. The open nanoarchitecure allows fast gas exchange. The spectral change of the reflected light depends on the composition of the ambient atmosphere and also on the wing nanostructure. In this work we show the results of recent measurements on nine Polyommatine species with dorsal blue coloration. Their color is generated by similar pepper-pot type nanoarchitectures which exhibit species specific characteristics, associated with species specific color. Experiments were carried out changing the concentration and nature of test vapors while monitoring the spectral variations in time. Proper data processing results gas-selective and concentration dependent signals. Our work shows a way to a prospective integrated biological - optical sensor combining light-weight and low power consuming with environmental friendly production.

Abstract: High Si steels (base steel and with addition of 0.1, 0.3, 0.5mass% Mo) were oxidized in a N2-3%O2-20%H2O atmosphere at 1150oC for 0.3-10.8ks. The oxidation kinetics showed that base steel has the highest weight gain. In contrast, 0.5Mo has the lowest weight gain. From SEM results, the scale thickness decreased as Mo content increased. Distribution of alloying elements showed that Mo is enriched in internal oxidation zone (IOZ) and played a role in slowing the outward diffusion of Fe, thus, producing a thinner Fe oxide scale and lower weight gain.

Abstract: Housing industry is composed of several relative industries. Its scale structure conforms to the scale described by smiling curve. This paper studies the components of housing industry and describes the proportion between enterprises classified by scale. The detail significations of different stages in housing industry’s smiling curve are explored. There are two laws discussed explaining the developing trends of structure’s two-orientation evolvement and smiling curve of housing industry during the process of housing industrialization.

Abstract: The oxidation behavior of Fe–Si alloys at 1073K in air was investigated. The oxidation kinetics described by the parabolic rate law of diffusion controlled oxidation and the oxidation rate decrease with the increasing Si content. Fe-Si alloys were oxidized for different times at 1073K to obtain the same scale thickness of approximately 30μm. Observations of scale cross-sections indicated the structure of oxide scale and elemental distribution in oxide scales strongly depends on Si content. The oxide scale on Fe-Si alloys with low Si content consisted of three layers with an outer Fe₂O₃, an intermediate Fe₃O₄ and an inner FeO and some voids were formed in Fe₃O₄ and FeO layers. The Si-rich oxide layer was formed at the scale/alloy interface of Fe-Si alloys with high Si content. Furthermore, the amount of internal oxidation zone increased with the increasing Si content. Observations of scale cross-sections indicated that the structure of oxide scale and elemental distribution in oxide scale strongly depend on Si content.

Abstract: Key morphological features of rabbit hair were investigated and compared with these of cashmere fiber. When the rabbit fiber diameter was about 10um, the angle of scale edge to the fiber axis was small. When the fiber diameter was around 40um, scale edges inclined larger angles to the axis. In addition, no overlapping and checks along the scale edges were observed in such coarse hair. The rabbit fiber diameters were normally between 10um and 20um and the scales of these fibers were long strip shaped with sharp tip at the middle. There was obvious boundary in the cashmere fiber after dyeing. One side is far darker than the other. On the contrast, this bilateral structure was not observed in the rabbit hair samples. The cortical cells presented in an uneven distribution in the rabbit hair. The mean ratio of medulla (filled with plenty of air) to fiber diameter was about 40%, which provide excellent thermal insulation to the rabbit hair assemblies.

Abstract: Isothermal oxidation was carried out on Fe and Fe-(1.0 and 5.0mass%)Cr alloy at 800°C and 1000°C in dry (PH2O=1x10-4 atm) and wet (PH2O=0.035 atm) air. Fracture behavior of the scale was investigated using acoustic emission (AE) analysis during cooling. The water vapor content of the atmosphere has a major influence on the oxidation of the Fe-Cr alloys, whereas it has virtually no effect on the oxidation of Fe. During cooling, significant AE activity starts at about 450°C on the Fe and Fe-Cr alloys oxidized in wet air. This critical temperature is independent of sample composition, oxidation temperature and scale thickness. In the case of the oxidation of the Fe-Cr alloys in dry air, however, the critical temperature shifts to higher temperatures with increasing scale thickness and Cr content. Fracture behavior of the scale should be related to scale structure caused by sample composition and oxidation condition.