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Single-atom catalysts (SACs) with unitary active sites hold great promise for realizing high selectivity toward a single product in the CO2 electroreduction reaction (CO2RR). However, achieving high Faradaic efficiency (FE) of multielectron products like methane on SACs is still challenging. Herein, we report a pressure-regulating strategy that achieves 83.5 ± 4% FE for the CO2-to-CH4 conversion on the asymmetric Cu-N2 sites, representing one of the best CO2-to-CH4 performances. Elevated CO2 pressure was demonstrated as an efficient way to inhibit the hydrogen evolution reaction via promoting the competing adsorption of reactant CO2, regardless of the nature of the active sites. Meanwhile, the asymmetric Cu-N2 structure could endow the Cu sites with stronger electronic coupling with *CO, thus suppressing the desorption of *CO and facilitating the following hydrogenation of *CO to *CHO. This work provides a synergetic strategy of the pressure-induced reaction environment regulating and the electronic structure modulating for selective CO2RR toward targeted products.
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Degradation of underwater images severely limits people to exploring and understanding underwater world, which has become a fundamental but vital issue needing to be addressed in underwater optics. In this paper, we develop an effective solution for underwater image enhancement. We first employ an adaptive-adjusted artificial multi-exposure fusion (A-AMEF) and a parameter adaptive-adjusted local color correction (PAL-CC) to generate a contrast-enhanced version and a color-corrected version from the input respectively. Then we put the contrast enhanced version into the famous guided filter to generate a smooth base-layer and a detail-information containing detail-layer. After that, we utilize the color channel transfer operation to transfer color information from the color-corrected version to the base-layer. Finally, the color-corrected base-layer and the detail-layer are added together simply to reconstruct the final enhanced output. Enhanced results obtained from the proposed solution performs better in visual quality, than those dehazed by some current techniques through our comprehensive validation both in quantitative and qualitative evaluations. In addition, this solution can be also utilized for dehazing fogged images or improving accuracy of other optical applications such as image segmentation and local feature points matching.
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Infrared imaging has been widely used in the field of sea surface monitoring. Horizon detection is a key step before a target's detection, locating, and tracking in the sea-sky infrared scene. Reducing processing time while ensuring accuracy is the research focus of infrared horizon detection. This paper proposes a novel method of a line segment detector (LSD) algorithm with gradient direction filtering. First, the rough extraction of the sea-sky region is used to limit the size of the detected image, and then the potential horizon line segment is extracted, applying the improved LSD algorithm in the sea-sky region, which probably contains many false extraction results. Then, gradient direction filtering is designed to pick the horizon line segments in this step. Finally, the horizon line segments are stitched to obtain the whole horizon line based on random sample consensus. The results of the comparative experiments show that this novel method has high detection accuracy, and the processing time is significantly shortened; what is more, we can also conclude that this method has a good performance on the detection stability.
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Infrared maritime target detection is the key technology of maritime target search systems. However, infrared images generally have the defects of low signal-to-noise ratio and low resolution. At the same time, the maritime environment is complicated and changeable. Under the interference of islands, waves and other disturbances, the brightness of small dim targets is easily obscured, which makes them difficult to distinguish. This is difficult for traditional target detection algorithms to deal with. In order to solve these problems, through the analysis of infrared maritime images under a variety of sea conditions including small dim targets, this paper concludes that in infrared maritime images, small targets occupy very few pixels, often do not have any edge contour information, and the gray value and contrast values are very low. The background such as island and strong sea wave occupies a large number of pixels, with obvious texture features, and often has a high gray value. By deeply analyzing the difference between the target and the background, this paper proposes a detection algorithm (SRGM) for infrared small dim targets under different maritime background. Firstly, this algorithm proposes an efficient maritime background filter for the common background in the infrared maritime image. Firstly, the median filter based on the sensitive region selection is used to extract the image background accurately, and then the background is eliminated by image difference with the original image. In addition, this article analyzes the differences in gradient features between strong interference caused by the background and targets, proposes a small dim target extraction operator with two analysis factors that fit the target features perfectly and combines the adaptive threshold segmentation to realize the accurate extraction of the small dim target. The experimental results show that compared with the current popular small dim target detection algorithms, this paper has better performance for target detection in various maritime environments.
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In many actual applications, fused image is essential to contain high-quality details for achieving a comprehensive representation of the real scene. However, existing image fusion methods suffer from loss of details because of the error accumulations of sequential tasks. This paper proposes a novel fusion method to preserve details of infrared and visible images by combining new decomposition, feature extraction, and fusion scheme. For decomposition, different from the most decomposition methods by guided filter, the guidance image contains only the strong edge of the source image but no other interference information so that rich tiny details can be decomposed into the detailed part. Then, according to the different characteristics of infrared and visible detail parts, a rough convolutional neural network (CNN) and a sophisticated CNN are designed so that various features can be fully extracted. To integrate the extracted features, we also present a multi-layer features fusion strategy through discrete cosine transform (DCT), which not only highlights significant features but also enhances details. Moreover, the base parts are fused by weighting method. Finally, the fused image is obtained by adding the fused detail and base part. Different from the general image fusion methods, our method not only retains the target region of source image but also enhances background in the fused image. In addition, compared with state-of-the-art fusion methods, our proposed fusion method has many advantages, including (i) better visual quality of fused-image subjective evaluation, and (ii) better objective assessment for those images.
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This article for the first time reports a large set of monitoring results for formaldehyde exposure during grossing activities in health care anatomic pathology laboratories, and compares the effectiveness of different local exhaust ventilation systems on the exposure. To control the confounding effects from grossing work load, sampling duration, and the sizes of specimens grossed, only 15-min short-term personal exposure samples collected during large tissue specimen grossing were used for the comparison of the effectiveness of these local exhaust systems. While we also collected long-term 8-hr time weighted average samples, these are not treated in this analysis. The systems examined were canopy receiving hoods, slot exhausts, and commercially available pre-manufactured backdraft grossing stations, both recirculating and ducted exhaust types. Out of over 2,000 personal short-term air samples, 307 samples from 163 surveys met the data selection criteria. Over a third of the data were less than the analytical laboratory limits of detection. Using the robust maximum likelihood estimation method for multiple limits of detection, the mean and geometric mean of the dataset for each type of local exhaust system were found to be less than the short-term personal exposure regulatory limit of 2 ppm. Nonparametric Wilcoxon rank-sum pairwise tests of five types of engineering controls showed a statistically significant difference among these controls, with the most effective being the manufactured backdraft grossing stations ducted to the outside, and the least effective being canopy exhaust systems and manufactured filtered recirculating grossing stations. Finally, exposure with each of the major engineering control types was rated by the American Industrial Hygiene Association exposure control rating scheme.
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Poluentes Ocupacionais do Ar/análise , Formaldeído/análise , Laboratórios Hospitalares , Exposição Ocupacional/prevenção & controle , Ventilação/instrumentação , Patologia ClínicaRESUMO
Infrared maritime target detection is a key technology for maritime target searching systems. However, in infrared maritime images (IMIs) taken under complicated sea conditions, background clutters, such as ocean waves, clouds or sea fog, usually have high intensity that can easily overwhelm the brightness of real targets, which is difficult for traditional target detection algorithms to deal with. To mitigate this problem, this paper proposes a novel target detection algorithm based on texture orientation. This algorithm first extracts suspected targets by analyzing the intersubband correlation between horizontal and vertical wavelet subbands of the original IMI on the first scale. Then the self-adaptive wavelet threshold denoising and local singularity analysis of the original IMI is combined to remove false alarms further. Experiments show that compared with traditional algorithms, this algorithm can suppress background clutter much better and realize better single-frame detection for infrared maritime targets. Besides, in order to guarantee accurate target extraction further, the pipeline-filtering algorithm is adopted to eliminate residual false alarms. The high practical value and applicability of this proposed strategy is backed strongly by experimental data acquired under different environmental conditions.
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There is an urgent need to develop a cost-effective and highly efficient acidic OER catalyst to support the progress of proton exchange membrane water electrolysis technology. Ruthenium-based catalysts, which possess high activity and significantly lower cost compared to iridium-based catalysts, emerge as competitive candidates. However, their suboptimal stability constrains the wide application of RuO2. Herein, we develop ultra-small Bi0.05Ru0.95O2 nanocrystal with diameter of approximately 6.5 ± 0.1 nm for acidic OER. The Bi0.05Ru0.95O2 nanocrystal electrocatalyst exhibits a low overpotential of 203.5 mV at 10 mA cm-2 and 300+ hour stability at a high water-splitting current density of 100 mA cm-2 in 0.5 M H2SO4 with a low decay rate of 0.44 mV h-1. Density functional theory (DFT) calculation results confirmed the adsorbate evolving mechanism (AEM) occurring on Bi0.05Ru0.95O2, which prevents lattice oxygen from participating in the reaction, thus avoiding the collapse of the structure. We proved that the Bi dopants could play a crucial role in not only reducing the energy barrier of the potential-determining step, but also delivering electrons to Ru sites, thereby alleviating the over-oxidation of Ru active sites and enhancing operation durability.
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Electrocatalytic two-electron water oxidation affords a promising approach for distributed production of H2O2 using electricity. However, it suffers from the trade-off between the selectivity and high production rate of H2O2 due to the lack of suitable electrocatalysts. In this study, single atoms of Ru were controllably introduced into titanium dioxide to produce H2O2 through an electrocatalytic two-electron water oxidation reaction. The adsorption energy values of OH intermediates could be tuned by introducing Ru single atoms, offering superior H2O2 production under high current density. Notably, a Faradaic efficiency of 62.8% with an H2O2 production rate of 24.2 µmol min-1 cm-2 (>400 ppm within 10 min) was achieved at a current density of 120 mA cm-2. Consequently, herein, the possibility of high-yield H2O2 production under high current density was demonstrated and the importance of regulating intermediate adsorption during electrocatalysis was evidenced.
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With the increasing attention to the cultivation of legal talents, a new teaching model has been explored through artificial intelligence (AI) technology under educational psychology, which focuses on improving learning initiative, teaching methods, and teaching quality of students. First, the application of AI and deep neural network (DNN) algorithms are reviewed in education, and the advantages and disadvantages of traditional learning material recommendation algorithms are summarized. Then, a personalized learning material recommendation algorithm is put forward based on DNN, together with an adaptive learning system based on DNN. Finally, the traditional user-based collaborative filtering (UserCF) model and lifelong topic modeling (LTM) algorithm are introduced as the control group to verify the performance of the proposed recommendation system. The results show that the best learning rate of model training is 0.0001, the best dropout value is 0.5, and the best batch size is 32. The proposed personalized learning resource recommendation method based on deep learning (DL) still has good stability under various training data scales. The personalized test questions of recommended students are moderately difficult. It is easier to recommend materials according to the acquisition of knowledge points and the practicability of the recommended test questions of students. Personalized learning material recommendation algorithm based on AI can timely feedback needs of students, thereby improving the effect of classroom teaching. Using the combination of AI and DL algorithms in teaching design, students can complete targeted personalized learning assignments, which is of great significance to cultivate high-level legal professionals.
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Small and medium-sized enterprises have been the driving force of social economy. As the social formation and the rise of many emerging economies, the domestic economic environment changes dramatically, which makes small and medium-sized enterprises face severe challenges. In the face of the fierce competition environment, how to improve the performance of entrepreneurship and gain competitive advantage is a very important topic in the practical management of entrepreneurs. This exploration is carried out with the entrepreneurial passion and risk taking as the antecedent variable, entrepreneurial performance as the outcome variable, and then work engagement as the mediator. With the entrepreneurs of small and medium-sized enterprises as the research object, questionnaire method is used to carry out empirical research. The empirical analysis results show that entrepreneurial passion has a significant positive impact on work engagement; risk taking has a significant positive impact on work engagement; work engagement has a significant positive impact on entrepreneurship performance; in addition, work participation plays a mediating role in the process of entrepreneurial passion and risk taking. The results provide academic and practical implications for entrepreneurs.
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Whole glove testing for a metalworking fluid (MWF) in the field was performed for the first time. Green latex gloves used in a machine shop were exposed for 20 min to MWF. The permeated amount (1.0 +/- 0.5 microg/cm(2)) was higher than the threshold (0.25 microg/cm(2)) for the ASTM F739-99a closed-loop normalized breakthrough time.
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Poluentes Ambientais/química , Luvas Protetoras , Metalurgia , Exposição Ocupacional , Análise de Falha de Equipamento , Humanos , PermeabilidadeRESUMO
This study explores the influence of psychological capital on the deviant innovation behavior, with the purpose of realizing the application and development of positive psychology in the field of innovation and creation. First, the data was obtained based on the questionnaire, and the Likert scale was adopted to measure the variables effectively, in which 1 point means "never," 2 points mean "rarely," and 5 points mean "always." Second, the SPSS 26.0 statistical analysis software was adopted, and a statistical analysis was made on the correlation among deviant innovation, psychological capital, work values, and work remodeling. Third, the relationship between psychological capital and deviant innovation behavior was explored using the analytic hierarchy process (AHP). The results showed that the reliability of each scale is good, Cronbach's α coefficients are all higher than 0.8, and the fitting effect of the four-factor model is the best, proving that the highest differentiation validity can be achieved using the proposed method. Furthermore, there are significant correlations among entrepreneur's psychological capital, entrepreneur's work values, and entrepreneurship work remodeling and deviant innovation behavior, among which the psychological capital and work values are the most correlated with deviant innovation. With the psychological capital of entrepreneurs as the adjustment variable and the interaction added, the explanation rate of the level equation is increased from 17 to 24.2%. Therefore, the psychological capital of entrepreneurs plays a very big role in regulating work values and deviant innovation behavior. In the current environment of innovation and entrepreneurship development, it is necessary for entrepreneurs to give full reign to the regulatory role of their own psychological capital, so as to promote the development of self-active deviant innovation activities and encourage employees to actively innovate and create.
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The dark adaptation of drivers' eyes at a tunnel entrance seriously affects traffic safety. This can be improved by the design of tunnel lighting. Light-Emitting Diode (LEDs) have been applied as a new type of luminaire in tunnel lighting in recent years, but at present, there are few studies on the influence of color rendering of LEDs on tunnel traffic safety, and there is no explicit indicator for the selection of appropriate color rendering parameters in tunnel lighting specifications, which has aroused researchers' concern. In this article, several new color rendering evaluation indexes were compared, and as a result, it is considered that CRI2012 (a color difference-based color rendering index) is more suitable for evaluating the color rendering of LEDs used at tunnel entrances. The dark adaptation phenomenon was simulated in the laboratory. Four CRI2012s, three color temperatures and eight colored targets were used in the experiments. The results showed that yellow, silver and white can provide shorter reaction times, while red and brown lead to longer reaction times, which can provide a reference for the design of road and warning signs at tunnel entrances. The effect of target color on reaction time was greater than that of color rendering. Under most target colors, the higher the CRI2012, the shorter the reaction time. When designing the color rendering of the LEDs at a tunnel entrance, the value should thus be as large as possible (close to 100), and a lower color temperature value (about 2800 K) should be selected. This paper provides technical support for tunnel lighting design and a reference for tunnel lighting specifications, which is of significance to improve driving safety and avoid traffic accidents in highway tunnels.
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Condução de Veículo , Cor , Adaptação à Escuridão , Iluminação , Acidentes de Trânsito/prevenção & controle , HumanosRESUMO
The influence of collection solvents hexane and perfluorohexane on the permeation of the non-polar and non-volatile di-n-octyl disulfide (DOD) through nitrile glove material was investigated using the American Society for Testing and Materials (ASTM) F739-99a method. The weight and the thickness of the nitrile material increased about 6%, statistically significant at pAssuntos
Ácidos Alcanossulfônicos/química
, Fluorocarbonos/química
, Luvas Protetoras
, Nitrilas/química
, Solventes/química
, Cromatografia Gasosa/métodos
, Desenho de Equipamento
, Fluorocarbonos/análise
, Cromatografia Gasosa-Espectrometria de Massas/métodos
, Substâncias Perigosas
, Espectrometria de Massas/métodos
, Teste de Materiais
, Modelos Estatísticos
, Exposição Ocupacional
, Roupa de Proteção
, Fatores de Tempo
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The aim of this study was to investigate how vehicle speed influences the characteristics of driver's eye movement at highway tunnel entrances during day and night. In this study, six drivers' eye movement data (from 200 m before tunnel entrance to 200 m inside tunnel entrance) under five predetermined vehicle speeds (40, 50, 60, 70 and 80 km/h) in the daytime and three predetermined vehicle speeds (40, 60 and 80 km/h) in the nighttime were recorded using the non-intrusive Dikablis Professional eye-tracking system. Pupil size, the average fixation duration time and the average number of fixation were analyzed and then the influence of the vehicle speed on these parameters was evaluated by means of IBM SPSS Statistics 20.0. The results for pupil size in daytime increased when approaching the tunnel entrance, while as for nighttime, pupil size decreased when approaching the tunnel entrance and then increased after entering the tunnel. The pupil size in daytime has a significant negative correlation with vehicle speed, while the pupil size in nighttime did not show a significant association with vehicle speed. Furthermore, the average fixation duration in daytime increased when entering the tunnel, and had a significant negative correlation with vehicle speed. Also, the average number of fixations in daytime decreased when entering the tunnel and has a significant negative correlation with vehicle speed. However, the average fixation duration and the average number of fixations in nighttime did not show any significant association with vehicle speed. Moreover, limitations and future directions of the study are discussed for the further investigation.
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Condução de Veículo/estatística & dados numéricos , Movimentos Oculares/fisiologia , Luz , Adulto , Escuridão , Humanos , Masculino , Pessoa de Meia-Idade , Projetos PilotoRESUMO
The aim was to investigate the permeation of a straight oil metalworking fluid (MWF) through four types of glove materials using the gravimetric method and the modified American Society for Testing and Materials (ASTM) F739-99a method with perfluorohexane and hexane as collection solvents. The residual masses on the collection side were determined after solvent evaporation for both MWF and blank (air) challenges. With perfluorohexane, the permeated MWF through gloves after 8h was around the lower quantifiable limit for nitrile, 0.7+/-0.2mg/cm(2) for vinyl, 10.0+/-1.2mg/cm(2) for chloroprene, and 33.0+/-0.7mg/cm(2) for latex. Hexane increased the amounts and rates of MWF permeating all gloves 39-73 times, except for vinyl where extractable mass was so high that the residues for MWF challenges and for hexane blanks were indistinguishable. Hexane as a collection solvent also extracted more glove components than did perfluorohexane, and back-permeated gloves in much larger amounts. Perfluorohexane allows better estimates of the real permeation rates and breakthrough times than does hexane. Recommendations based on breakthrough times and permeation rates with hexane collection are thus too conservative, although the relative ranking of these four types of gloves was the same with either collection solvent.
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Cloropreno/química , Luvas Protetoras , Látex/química , Óleo Mineral/química , Nitrilas/química , Exposição Ocupacional , Cloreto de Polivinila/química , Permeabilidade , Solventes/químicaRESUMO
The aim of this study was to identify and quantify an unknown peak in the chromatogram of a very complex mixture, a straight oil metalworking fluid (MWF). The fraction that permeated through a thin nitrile polymer membrane had less mineral oil background than the original MWF did at the retention time of the unknown peak, thus facilitating identification by total ion current (TIC) gas chromatography-mass spectrometry (GC-MS). The peak proved to be di-n-octyl disulfide (DOD) through retention time and mass spectral comparisons. Quantitation of DOD was by extracted ion chromatogram analysis of the DOD molecular ion (mass-to-charge ratio (m/z) 290), and of the m/z 71 ion for the internal standard, n-triacontane. Linear models of the area ratio (y) of these two ions versus DOD concentration showed a systematic negative bias at low concentrations, a common occurrence in analysis. The linear model of y(0.8) (from Box-Cox power transformation) versus DOD concentration showed negligible bias from the lowest measured standard of 1.51 mg/L to the highest concentration tested at 75.5 mg/L. The intercept did not differ statistically from zero. The concentration of DOD in the MWF was then calculated to be 0.398+/-0.034% (w/w) by the internal standard method, and 0.387+/-0.036% (w/w) by the method of standard additions. These two results were not significantly different at p < or = 0.05. The Box-Cox transformation is therefore recommended when the data for standards are non-linear.
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Ácidos Alcanossulfônicos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Metalurgia/métodos , Calibragem , Interpretação Estatística de DadosRESUMO
The aim of the present study was to quantify the permeation parameters of a complex water-insoluble straight oil metalworking fluid (MWF) of low volatility through nitrile gloves. The permeation through a chemically protective and a disposable glove was investigated using the American Society for Testing and Materials (ASTM) F739-99a method with hexane as the collection medium. Analysis of collection side samples involved gas chromatography-mass spectrometry (GC-MS) and gravimetry. The detection breakthrough time for the chemically protective glove was >10 h. For the disposable glove, the detection breakthrough time was 0.7+/-0.3 h, the lag time was 1.6+/-0.1 h, the diffusion coefficient was (3.7+/-0.3)x10(-9) cm2/min, and the steady state permeation rate was 3.5+/-2.2 microg/cm2/min. The disposable nitrile glove can be worn for about 30 min for incidental contact with straight oil MWFs without known carcinogens. The chemically protective nitrile glove should be worn otherwise. The chromatogram for the permeate differed from that of the original MWF, resulting from the faster permeation of lower molecular weight congeners. The combination of chromatography and gravimetry allowed quantifying the permeation parameters of complex water-insoluble non-volatile mixtures.
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Luvas Protetoras , Óleo Mineral/química , Nitrilas/química , Óleos de Plantas/química , Cromatografia Gasosa-Espectrometria de Massas , PermeabilidadeRESUMO
The performance of protective gloves against metalworking fluids (MWFs) has rarely been studied because of the difficult chemical analysis associated with complex MWFs. In the present study, glove swelling was used as a screening parameter of glove compatibility after challenge of the outer surfaces of chloroprene, latex, nitrile, and vinyl disposable gloves by six MWF concentrates for 2 hours in an ASTM F-739-type permeation cell without collection medium. Swelling relative to original thickness was up to 39% for latex, 7.6% for chloroprene, and 3.5% for nitrile. Shrinking up to 9.3% occurred for vinyl. Chloroprene and latex did not swell significantly for the semisynthetic and synthetic MWFs. Vinyl, previously not tested, was a good candidate for MWFs other than the soluble oil type. Although nitrile was recommended by the National Institute for the Occupational Safety and Health (NIOSH) for all types of MWFs, its swelling after 2-hour challenge was significant with Student t-tests for the soluble oil, synthetic, and semisynthetic MWFs. Glove swelling can be used as a screening chemical degradation method for mixtures such as MWFs with difficult chemical analysis. Further studies need to be conducted on the relationship between permeation and glove swelling.