FM-KPFM TappingMode Ram UTEM HydroGel LiquidImaging SSRM Device thermal_conductivity Composition Piezo Chungnam_National_University CuParticle Polyurethane HfO2 bias_mode Melt EFMAmplitude LowDensityPolyethylene Workfunction Annealing Thermoplastic_polyurethane aluminum_nitride Gong VerticalPFM Mobile high_resolution DiffractiveOpticalElements Conduct MfmAmplitude Led TipBiasMode fifber Composite BFO