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Lead (Pb) is one of the most widespread and highly toxic heavy metals in the environment. The design and synthesis of adsorbent materials for the selective and efficient removal of Pb2+ from aqueous solution has received much attention. Herein, the ligand 4,4′-azoxydibenzoic acid with the O− group was elaborately selected to construct a novel Pr-based MOF for Pb2+ removal. The as-prepared MOF adsorbents with high stability exhibited ultra-high selectivity for Pb2+, even in the presence of various highly concentrated competitive ions (with the ratios from 1 : 5 to 1 : 50). Also, a high uptake capacity (560.26 mg g−1) can be achieved for the MOF material, due to the availability of sufficient adsorption sites. The strong electrostatic attraction and coordination interaction between the numerous active O− sites on MOF adsorbents and Pb2+ can account for the good adsorption performance for Pb2+, which was systematically verified by zeta potential, FT-IR and XPS studies. [ABSTRACT FROM AUTHOR]

Content-aware image retargeting is a technique that can flexibly display images with different aspect ratios and simultaneously preserve salient regions in images. Recently many image retargeting techniques have been proposed. To compare image quality by different retargeting methods fast and reliably, an objective metric simulating the human vision system (HVS) is presented in this paper. Different from traditional objective assessment methods that work in bottom-up manner (i.e., assembling pixel-level features in a local-to-global way), in this paper we propose to use a reverse order (top-down manner) that organizes image features from global to local viewpoints, leading to a new objective assessment metric for retargeted images. A scale-space matching method is designed to facilitate extraction of global geometric structures from retargeted images. By traversing the scale space from coarse to fine levels, local pixel correspondence is also established. The objective assessment metric is then based on both global geometric structures and local pixel correspondence. To evaluate color images, CIE L*a*b* color space is utilized. Experimental results are obtained to measure the performance of objective assessments with the proposed metric. The results show good consistency between the proposed objective metric and subjective assessment by human observers. [ABSTRACT FROM AUTHOR]

Lead (Pb) is one of the most widespread and highly toxic heavy metals in the environment. The design and synthesis of adsorbent materials for the selective and efficient removal of Pb 2+ from aqueous solution has received much attention. Herein, the ligand 4,4'-azoxydibenzoic acid with the O - group was elaborately selected to construct a novel Pr-based MOF for Pb 2+ removal. The as-prepared MOF adsorbents with high stability exhibited ultra-high selectivity for Pb 2+ , even in the presence of various highly concentrated competitive ions (with the ratios from 1 : 5 to 1 : 50). Also, a high uptake capacity (560.26 mg g -1 ) can be achieved for the MOF material, due to the availability of sufficient adsorption sites. The strong electrostatic attraction and coordination interaction between the numerous active O - sites on MOF adsorbents and Pb 2+ can account for the good adsorption performance for Pb 2+ , which was systematically verified by zeta potential, FT-IR and XPS studies.