Academic literature on the topic 'Copper red'

A green synthesis of copper oxide nanoparticles and its removal efficiency of azodye were studied. Biosynthesis of stable copper oxide nanoparticles were preformed using Aloe barbadensis leaf extract as a size and shape-directing agent for preparing of spherical copper oxide nanoparticles by calcination at 400 °C. The leaf extract of Aloe barbadensis was prepared in deionized water. The produced copper particles were calcined at 400 °C to produce copper oxide nanoparticles. The characterization of copper oxide nanoparticles was performed by XRD, SEM, FTIR, UV spectroscopy. The XRD analysis showed that the average particle size was between 5-30 nm. The shape of the copper oxide nanoparticles was spherical and cubic. EDX of the synthesized nanoparticles showed the composition consists of 68 % copper. The UV-visible spectrum analysis confirms an absorption peak at 200-400 nm of the produced CuO nanoparticles. The FTIR analysis of the copper oxide particles indicate the presence of the organometallic Cu-O bond between Cu and O. The obtained copper oxide was used as a removing agent of Congo red dye. The effect of variables like concentration, time, pH, adsorbent dosage were studied. It was observed from the results that the maximum dye removal occurs at pH of 4, the concentration of nanoparticles was 1 mg/L and the maximum time for dye removal was 120 min. The Langmuir isotherm model was calculated to study the adsorption efficiency of the Congo red dye on the produced copper oxide nanoparticles. The kinetics of pseudo second order is followed by adsorption. The calculated sum of square was 0.012 and r2 = 0.98. it was observed that the model fit the best and straight line with r2 value of 0.991 and probability value of 1.6E-5. The nanoparticles remove 70 % of the Congo red dye from its solution. This showed that the copper oxide nanoparticles has efficient capacity of azodye degradation.

Red copper is difficult to process with laser for its high reflection rate and high density. On the contrary, with the development of Modern Laser Micro-Jet processing, the new Laser Micro-jet with 30μm and 130μm are utilized to process new area like red copper plate etc., new Laser Micro-jet with 30μm nozzle is redesigned as well as working experiment on red copper is carried out. Red copper is machining with the Laser Micro-Jet The experiment shows the methods can improve the red copper‘s machining quality, on the contrary, the result of experiment shows the new laser processing methods can machine red copper efficiently.

Underglaze copper-red decoration,i.e.the copper colourant used to paint diversified patterns on the surface of a body and then covered by transparent glaze and fired at high temperature in a reductive firing environment, is famous all over the world. However, the red colouration mechanism generated by underglaze copper remains unclear. In particular, the fact that the edges of the red patterns are orange has been ignored in previous research. Here, non-destructive analysis has been carried out on a precious fragment of early underglaze red porcelain using synchrotron radiation X-ray fluorescence, X-ray absorption near-edge spectroscopy (XANES) and reflection spectrometry techniques. The results suggest that the copper content in the red region is higher than that in the orange region, and other colour generation elements do not have obvious content difference, indicating that the colour generation effect of the underglaze red product is related to the copper content. XANES analysis shows that the valence states of copper in the red and orange regions are similar and metal copper contributes to their hues. The results of reflection spectrometry demonstrate that tiny orange hues could be attributed to the Mie scatting effect. Therefore, light-scattering effects should be considered when researching the colouration mechanism of underglaze red.

The origin of chalcocite is explored through a comparison of the copper isotope values of this mineral from supergene enrichment, sedimentary copper/red bed, and high-temperature hypogene mineralization around the world. Data from the literature and the data presented here (n=361) reveal that chalcocite from high-temperature mineralization has the tightest cluster of values of δCu65=0±0.6 in comparison to sedimentary copper/red bed δCu65=-0.9±1.0 and supergene enrichment δCu65=+1.9±1.8. Although the errors of the means overlap, large portions of the data lie in different values, allowing for distinguishing ranges for δCu65 of <−1‰ for sedimentary copper/red bed, between -1 and +1 for high-temperature hypogene, and >+1 for supergene enrichment chalcocite. The copper isotope values of sedimentary copper/red bed and supergene enrichment chalcocite are caused by redox reactions associated with the dissolution and transport of copper, whereas the tighter range of copper isotope values for hypogene minerals is associated with processes active with equilibrium conditions.

Red copper has been widely used in shaped charge liner because of its good ductility. Red copper penetrator is the Linear Explosively Formed Penetrator (LEFP) with some length and energy which has been produced when linear red copper shaped charge liner is overturned under the effect of detonation production. Compared with some ordinary jets sword, it has some characteristics such as the broad range of stand-off, big cratering and obvious rear effect and may meet with many operating requirements in different environment. It has been discovered that the bifurcate fracture phenomenon of red copper penetrator will occur with the increase of stand-off when it is initiated on edge midpoint in its property test experiment, and results in the separating cratering on the target which influences its effect. The Propagation characteristics of detonation wave in explosive and the effect of detonation wave on red copper shaped charge liner are analyzed, and then the velocity change obtained by each element and the velocity relationship between each element are studied. So it can be drawn a conclusion that the velocity gradient is the main factor which results in the bifurcate fracture phenomenon of red copper penetrator. In addition, the theoretic analysis model of the bifurcate fracture in red copper penetrator is built. On the basis of modeling analysis and calculation, the criterion of the occurring bifurcate fracture and the measures avoiding the bifurcate fracture are put forward. The results agree well with that of experiments.