Analisis Pengaruh Konsentrasi Zinc Acetate Dihydrate Terhadap Karakteristik Lapisan Electrospinning Polyvinyl Alcohol pada Magnesium sebagai Biomaterial Implan Mampu Luruh = Analysis of the Zinc Acetate Dihydrate Concentration Effect on the Characteristics of Electrospinning Polyvinyl Alcohol Coatings on Magnesium as an Implantable Biomaterial