2,5-diformylfuran 5-hydroxymethylfurfural CVD process Halloysite Nanotubes History of engineering & technology LEDs SERS Technology: general issues TiO2 alternating current boron boron-doped diamond carbon quantum dots copper cation densification direct ethanol fuel cell doping electrocatalysis electrochemical dispersion electrochemical synthesis ethanol electrooxidation fluorescence properties fuel cell heavy metals hot rolling ion exchange low-carbon steels of the ferritic class maleated natural rubber maleic anhydride mechanical processing