Research institute of Innovative Products and Technologies, The Hong Kong Polytechnic University, Hong Kong SAR, PR China.|Research institute of Innovative Products and Technologies, The Hong Kong Polytechnic University, Hong Kong SAR, PR China.|Research institute of Innovative Products and Technologies, The Hong Kong Polytechnic University, Hong Kong SAR, PR China.|Research institute of Innovative Products and Technologies, The Hong Kong Polytechnic University, Hong Kong SAR, PR China.