Hong Kong Polytechnic University

About: Hong Kong Polytechnic University is a education organization based out in Hong Kong, China. It is known for research contribution in the topics: Computer science & Tourism. The organization has 29633 authors who have published 72136 publications receiving 1956312 citations. The organization is also known as: HKPU & PolyU.

Accurate iris segmentation based on novel reflection and eyelash detection model

Abstract: The authors propose a novel noise detection model for accurate segmentation of an iris. Eyelash, eyelid and reflection are three main noises. Eyelid has already been solved by a traditional eye model; however, eyelash and reflection have not been tackled. To determinate a pixel in an eyelash, the model presented follows the three criteria: 1) separable eyelash condition; 2) non-informative condition; and 3) connective criterion. The first and second conditions handle separable and multiple eyelashes respectively. The last criterion avoids misclassification of strong iris texture as a single and separable eyelash. For reflection, strong reflection points are detected by a threshold and the weak reflection points around the strong points are determined by connective criterion and statistical test. A number of images are selected to evaluate the accuracy and necessity of our noise detection model and the results are encouraging.

Iridium Single Atoms Coupling with Oxygen Vacancies Boosts Oxygen Evolution Reaction in Acid Media

Abstract: Simultaneous realization of improved activity, enhanced stability, and reduced cost remains a desirable yet challenging goal in the search of electrocatalysis oxygen evolution reaction (OER) in acid. Herein, we report a novel strategy to prepare iridium single-atoms (Ir-SAs) on ultrathin NiCo2O4 porous nanosheets (Ir-NiCo2O4 NSs) by the co-electrodeposition method. The surface-exposed Ir-SAs couplings with oxygen vacancies (VO) exhibit boosting the catalysts OER activity and stability in acid media. They display superior OER performance with an ultralow overpotential of 240 mV at j = 10 mA cm-2 and long-term stability of 70 h in acid media. The TOFs of 1.13 and 6.70 s-1 at an overpotential of 300 and 370 mV also confirm their remarkable performance. Density functional theory (DFT) calculations reveal that the prominent OER performance arises from the surface electronic exchange-and-transfer activities contributed by atomic Ir incorporation on the intrinsic VO existed NiCo2O4 surface. The atomic Ir sites substantially elevate the electronic activity of surface lower coordinated Co sites nearby VO, which facilitate the surface electronic exchange-and-transfer capabilities. With this trend, the preferred H2O activation and stabilized *O have been reached toward competitively lower overpotential. This is a generalized key for optimally boosting OER performance.