Noise causes unpleasant visual effects in low-light image/video enhancement. In this paper, we aim to make the enhancement model and method aware of noise in the whole process. To deal with heavy ...noise which is not handled in previous methods, we introduce a robust low-light enhancement approach, aiming at well enhancing low-light images/videos and suppressing intensive noise jointly. Our method is based on the proposed Low-Rank Regularized Retinex Model (LR3M), which is the first to inject low-rank prior into a Retinex decomposition process to suppress noise in the reflectance map. Our method estimates a piece-wise smoothed illumination and a noise-suppressed reflectance sequentially, avoiding remaining noise in the illumination and reflectance maps which are usually presented in alternative decomposition methods. After getting the estimated illumination and reflectance, we adjust the illumination layer and generate our enhancement result. Furthermore, we apply our LR3M to video low-light enhancement. We consider inter-frame coherence of illumination maps and find similar patches through reflectance maps of successive frames to form the low-rank prior to make use of temporal correspondence. Our method performs well for a wide variety of images and videos, and achieves better quality both in enhancing and denoising, compared with the state-of-the-art methods.
Modern engineered systems generally work under complex operational conditions. However, most of the existing artificial intelligence (AI)-based prognostic methods still lack an effective model that ...can utilize operational conditions data for remaining useful life (RUL) prediction. This paper develops a novel prognostic method based on bidirectional long short-term memory (BLSTM) networks. The method can integrate multiple sensors data with operational conditions data for RUL prediction of engineered systems. The proposed architecture based on BLSTM networks includes three main parts: first, one BLSTM network is used to directly extract features hidden in the multiple raw sensors signals; second, another BLSTM network is employed to learn higher features from operational conditions signals and the learned features from the sensors signals; and, third, fully connected layers and a linear regression layer are stacked to generate the target output of the RUL prediction. Unlike other AI-based prognostic methods, the developed method can simultaneously model both sensors data and operational conditions data in a consolidated framework. The proposed approach is demonstrated through a case study on aircraft turbofan engines, and comparisons with other popular state-of-the-art methods are also presented.
Electronic structure greatly determines the band structures and the charge carrier transport properties of semiconducting photocatalysts and consequently their photocatalytic activities. Here, by ...simply calcining the mixture of graphitic carbon nitride (g‐C3N4) and sodium borohydride in an inert atmosphere, boron dopants and nitrogen defects are simultaneously introduced into g‐C3N4. The resultant boron‐doped and nitrogen‐deficient g‐C3N4 exhibits excellent activity for photocatalytic oxygen evolution, with highest oxygen evolution rate reaching 561.2 µmol h−1 g−1, much higher than previously reported g‐C3N4. It is well evidenced that with conduction and valence band positions substantially and continuously tuned by the simultaneous introduction of boron dopants and nitrogen defects into g‐C3N4, the band structures are exceptionally modulated for both effective optical absorption in visible light and much increased driving force for water oxidation. Moreover, the engineered electronic structure creates abundant unsaturated sites and induces strong interlayer C–N interaction, leading to efficient electron excitation and accelerated charge transport. In the present work, a facile approach is successfully demonstrated to engineer the electronic structures and the band structures of g‐C3N4 with simultaneous introduction of dopants and defects for high‐performance photocatalytic oxygen evolution, which can provide informative principles for the design of efficient photocatalysis systems for solar energy conversion.
Boron dopants and nitrogen defects are simultaneously introduced into g‐C3N4 through a simple NaBH4 thermal treatment approach. With exceptionally modulated band structures for effective optical absorption and increased water‐oxidation driving force, as well as engineered electronic structure for efficient electron excitation and facilitated charge transport, the resultant boron‐doped and nitrogen‐deficient g‐C3N4 exhibits excellent activity for photocatalytic oxygen evolution.
The electrosynthesis from 5‐hydroxymethylfurfural (HMF) is considered a green strategy to achieve biomass‐derived high‐value chemicals. As the molecular structure of HMF is relatively complicated, ...understanding the HMF adsorption/catalysis behavior on electrocatalysts is vital for biomass‐based electrosynthesis. The electrocatalysis behavior can be modulated by tuning the adsorption energy of the reactive molecules. In this work, the HMF adsorption behavior on spinel oxide, Co3O4 is discovered. Correspondingly, the adsorption energy of HMF on Co3O4 is successfully tuned by decorating with single‐atom Ir. It is observed that compared with bare Co3O4, single‐atom‐Ir‐loaded Co3O4 (Ir‐Co3O4) can enhance adsorption with the CC groups of HMF. The synergetic adsorption can enhance the overall conversion of HMF on electrocatalysts. With the modulated HMF adsorption, the as‐designed Ir‐Co3O4 exhibits a record performance (with an onset potential of 1.15 VRHE) for the electrosynthesis from HMF.
Single atoms of Ir are anchored on Co3O4 for efficient electro‐oxidation of 5‐hydroxymethylfurfural (HMF). It is found that an isolated Ir atom can optimize the adsorption configuration of HMF molecules on catalysts and accelerate HMF oxidation.
Research Summary
We add to the literature examining the ownership‐innovation relationship by examining two major investor types: corporate investors and family investors. We use organizational ...environmental scanning as a new perspective to understand how these investors' capabilities influence firms' external cooperation and innovation performance. We found that corporate investors with broad investment experience strengthen a firm's environmental scanning, enhancing innovation performance by increasing the number of external cooperation activities the firm engages in. Conversely, family investors' broad investment experience tend to be negatively associated with the number of external cooperation and with firm innovation. Our results show that investors influence firm innovation not simply through a monitoring role but also by affecting firms' abilities to innovate, once we factor in the types of investors and their capabilities.
Managerial Summary
We investigate how two different types of investors, corporate and family, influence the innovation performance of publicly‐traded high‐tech firms in Taiwan. We found that the presence of major corporate investors with broad investment experience enhances firms' innovation performance by increasing external cooperation activities firms engage in. Corporate investors appear to enhance organizations' environmental scanning abilities and, in turn, their innovation performance. Conversely, family investors' broad investment experience is negatively associated with firm innovation because such firms engage in fewer external cooperation activities. A focus on control and social cohesion in family firms appears to decrease the emphasis on external knowledge acquisition when family investors have broad investment experience. In summary, our results show that investors' breadth of investment experience influences firms' ability to innovate.
The electrooxidation of 5‐hydroxymethylfurfural (HMF) offers a promising green route to attain high‐value chemicals from biomass. The HMF electrooxidation reaction (HMFOR) is a complicated process ...involving the combined adsorption and coupling of organic molecules and OH− on the electrode surface. An in‐depth understanding of these adsorption sites and reaction processes on electrocatalysts is fundamentally important. Herein, the adsorption behavior of HMF and OH−, and the role of oxygen vacancy on Co3O4 are initially unraveled. Correspondingly, instead of the competitive adsorption of OH− and HMF on the metal sites, it is observed that the OH− can fill into oxygen vacancy (Vo) prior to couple with organic molecules through lattice oxygen oxidation reaction process, which could accelerate the rate‐determining step of the dehydrogenation of 5‐hydroxymethyl‐2‐furancarboxylic acid (HMFCA) intermediates. With the modulated adsorption sites, the as‐designed Vo‐Co3O4 shows excellent activity for HMFOR with the earlier potential of 90 and 120 mV at 10 mA cm−2 in 1 m KOH and 1 m PBS solution. This work sheds insight on the catalytic mechanism of oxygen vacancy, which benefits designing a novel electrocatalysts to modulate the multi‐molecules combined adsorption behaviors.
The electrooxidation of 5‐hydroxymethylfurfural (HMFOR) process is complicated, including the HMF and OH− jointly adsorbed and coupled with each other. In this work, the role of oxygen vacancies is investigated during HMFOR. It is found that the OH− tends to fill into Vo and participate in the dehydrogenation of HMF molecules, which can improve the catalytic activity of HMFOR.
Combining noble metals with nonnoble metals is an attractive strategy to balance the activity and cost of electrocatalysts. However, a guiding principle for selecting suitable nonnoble metals is ...still lacking. Herein, a thorough mechanistic study on the platform oxygen evolution reaction (OER) electrocatalyst of Ir@Co3O4 to deeply understand the synergy between Ir and Co3O4 for the boosted OER has been carried out. It is demonstrated that the pseudocapacitive feature of Co3O4 plays a key role in accumulating sufficient positive charge Q, while the Ir sites are responsible for achieving a high reaction order (β), synergistically contributing to the high OER activity of Ir@Co3O4 through the rate law equation. Specifically, Ir@Co3O4 displays a low overpotential of 280 mV at 10 mA cm−2 with a small Ir loading of 1.4 wt%. Ir@Co3O4 is further applied to Zn‐air batteries, which enables a low charging potential and thus alleviates the oxidative corrosion of the air electrode, leading to improved cycle stability of 210 h at 20 mA cm−2. This work demonstrates that anchoring active noble metal sites (for high β) on pseudocapacitive supports (for high Q) is highly favorable to the OER process, providing a clear guidance for boosting the utilization of noble metals in electrocatalysis.
Ultra‐low loading Ir (1.4 wt%) is anchored on Co3O4 for oxygen evolution reaction (OER). The pseudocapacitive Co3O4 helps accumulate the positive charge Q, while the Ir sites help achieve a high reaction order (β). Anchoring the ultra‐low loading noble catalyst on the pseudocapacitive non‐noble catalyst is a promising strategy for high‐performance low‐cost catalyst development.
Rechargeable lithium metal batteries are next generation energy storage devices with high energy density, but face challenges in achieving high energy density, high safety, and long cycle life. Here, ...lithium metal batteries in a novel nonflammable ionic‐liquid (IL) electrolyte composed of 1‐ethyl‐3‐methylimidazolium (EMIm) cations and high‐concentration bis(fluorosulfonyl)imide (FSI) anions, with sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) as a key additive are reported. The Na ion participates in the formation of hybrid passivation interphases and contributes to dendrite‐free Li deposition and reversible cathode electrochemistry. The electrolyte of low viscosity allows practically useful cathode mass loading up to ≈16 mg cm−2. Li anodes paired with lithium cobalt oxide (LiCoO2) and lithium nickel cobalt manganese oxide (LiNi0.8Co0.1Mn0.1O2, NCM 811) cathodes exhibit 99.6–99.9% Coulombic efficiencies, high discharge voltages up to 4.4 V, high specific capacity and energy density up to ≈199 mAh g−1 and ≈765 Wh kg−1 respectively, with impressive cycling performances over up to 1200 cycles. Highly stable passivation interphases formed on both electrodes in the novel IL electrolyte are the key to highly reversible lithium metal batteries, especially for Li–NMC 811 full batteries.
A nonflammable ionic‐liquid electrolyte is developed for high‐safety and high‐energy‐density Li metal batteries, allowing practically useful cathode mass loading up to 16 mg cm−2, realizing high specific capacity and energy density (199 mAh g−1 and 765 Wh kg−1) with impressive cycling performances. The robust passivation interphases formed on both electrodes are key to realizing impressive battery performances.
Co‐based spinel oxides, which are of mixing valences with the presence of both Co2+ and Co3+ at different atom locations, are considered as promising catalysts for the electrochemical oxidation of ...5‐hydroxymethylfurfural (HMF). Identifying the role of each atom site in the electroxidation of HMF is critical to design the advanced electrocatalysts. In this work, we found that Co2+Td in Co3O4 is capable of chemical adsorption for acidic organic molecules, and Co3+Oh play a decisive role in HMF oxidation. Thereafter, the Cu2+ was introduced in spinel oxides to enhance the exposure degree of Co3+ and to boost acidic adsorption and thus to enhance the electrocatalytic activity for HMF electrooxidation significantly.
The exploration of optimal geometrical site in Co3O4 for electrochemical HMF oxidation by the building tetrahedral (Zn2+) and octahedral (Al3+) blocks is described. The electrochemical results demonstrate that Co3+Oh are the best geometrical sites for HMF oxidation, and the chemical adsorption for acidic organic molecules is dominated by Co2+Td. The exposure degree of Co3+ is improved by Cu2+ and thus results in a record activity.
Proper data placement schemes based on erasure correcting codes are one of the most important components for a highly available data storage system. For such schemes, low decoding complexity for ...correcting (or recovering) storage node failures is essential for practical systems. In this paper, we describe a new coding scheme, which we call the STAR code, for correcting triple storage node failures (erasures). The STAR code is an extension of the double-erasure-correcting EVENODD code and a modification of the generalized triple-erasure-correcting EVENODD code. The STAR code is an Maximum Distance Separable (MDS) code and thus is optimal in terms of node failure recovery capability for a given data redundancy. We provide detailed STAR code decoding algorithms for correcting various triple node failures. We show that the decoding complexity of the STAR code is much lower than those of existing comparable codes; thus, the STAR code is practically very meaningful for storage systems that need higher reliability.
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