Single-crystalline VO2 microtube arrays on V2O5 substrate were fabricated through a thermal oxidation route based on resistive heating V foil in air. Four sheets of as-fabricated single-crystalline VO2 microtube arrays on V2O5 substrate were then. respectively. heated to approximately 855 °C and 1660 °C to melt V2O5 or VO2. https://www.marcelovicente.com/product-category/semi-permanent-hair-color-2/