The automatic stealth task of military time-sensitive targets plays a crucial role in maintaining national military security and mastering battlefield dynamics in military applications.We propose a novel Military Time...The automatic stealth task of military time-sensitive targets plays a crucial role in maintaining national military security and mastering battlefield dynamics in military applications.We propose a novel Military Time-sensitive Targets Stealth Network via Real-time Mask Generation(MTTSNet).According to our knowledge,this is the first technology to automatically remove military targets in real-time from videos.The critical steps of MTTSNet are as follows:First,we designed a real-time mask generation network based on the encoder-decoder framework,combined with the domain expansion structure,to effectively extract mask images.Specifically,the ASPP structure in the encoder could achieve advanced semantic feature fusion.The decoder stacked high-dimensional information with low-dimensional information to obtain an effective mask layer.Subsequently,the domain expansion module guided the adaptive expansion of mask images.Second,a context adversarial generation network based on gated convolution was constructed to achieve background restoration of mask positions in the original image.In addition,our method worked in an end-to-end manner.A particular semantic segmentation dataset for military time-sensitive targets has been constructed,called the Military Time-sensitive Target Masking Dataset(MTMD).The MTMD dataset experiment successfully demonstrated that this method could create a mask that completely occludes the target and that the target could be hidden in real time using this mask.We demonstrated the concealment performance of our proposed method by comparing it to a number of well-known and highly optimized baselines.展开更多
Glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG), the major functional ingredient in licorice, has widespread applications in food, pharmacy and cosmetics industry. The production of GAMG through Penicillium purpu...Glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG), the major functional ingredient in licorice, has widespread applications in food, pharmacy and cosmetics industry. The production of GAMG through Penicillium purpurogenum Li-3 cultivation was for the first time performed through both batch and fed-batch processes in bioreactors. In batch process, under optimal conditions (pH 5.0, temperature 32℃, agitation speed 100 r. rain 1), 3.55 g. L^-1 GAMG was obtained in a 2.5 L fermentor. To further enhance GAMG production, a fine fed-batch process was developed by using pH and DO as feedback parameters. Starting from 48 h, 100 m190 g-L 1 substrate Glycyrrhizin (GL) was fed each time when pH increased to above 5.0 and DO was increased to above 80%. This strategy can significantly enhance GAMG production: the achieved GL conversion was 95.34% with GAMG yield of 95.15%, and GAMG concentration was 16.62 g. L^-1 which was 5 times higher than that of batch. Then, a two-step separation strat- egy was established to separate GAMG from fermentation broth by crude extraction of 15 ml column packed with D10I resin followed by fine purification with preparative C18 chromatography. The obtained GAMG purity was 95.79%. This study provides a new insight into the industrial bioprocess of high-level GAMG production.展开更多
Carbon dioxide reduction reaction(CO_(2)RR) represents an efficient approach to achieving carbon neutrality and simultaneously generating clean energy.However,the strong stability of CO_(2) molecules and the diversity...Carbon dioxide reduction reaction(CO_(2)RR) represents an efficient approach to achieving carbon neutrality and simultaneously generating clean energy.However,the strong stability of CO_(2) molecules and the diversity of products pose significant challenges.As an emerging material,bimetallic catalysts have been widely reported for their unique advantages,such as tunable electronic structures,suitable adsorption/desorption of CO_(2) and intermediates,and optimizable d-band centers of active sites through bimetallic synergy.These catalysts provide a remarkable platform for converting CO_(2) into high value-added chemicals.This review comprehensively summarizes recent research advances in bimetallic catalysts for CO_(2)RR.Firstly,the challenges associated with CO_(2)RR,including activity and selectivity are analyzed,followed by a discussion on the unique advantages of bimetallic catalysts.Next,their synthesis strategies are categorized into dual-atom site catalysts(DACs),bimetallic nanoparticles and nanoclusters,binary metal semiconductors,and layered double hydroxides(LDHs).Additionally,advanced characterization techniques of bimetallic catalysts and their applications in CO_(2)RR are thoroughly introduced.Finally,the prospects and challenges for the application of bimetallic materials are highlighted.This review aims to provide inspiration for CO_(2)RR into high-value chemicals and shed light on the research of bimetallic materials.展开更多
In recent years,many visual positioning algorithms have been proposed based on computer vision and they have achieved good results.However,these algorithms have a single function,cannot perceive the environment,and ha...In recent years,many visual positioning algorithms have been proposed based on computer vision and they have achieved good results.However,these algorithms have a single function,cannot perceive the environment,and have poor versatility,and there is a certain mismatch phenomenon,which affects the positioning accuracy.Therefore,this paper proposes a location algorithm that combines a target recognition algorithm with a depth feature matching algorithm to solve the problem of unmanned aerial vehicle(UAV)environment perception and multi-modal image-matching fusion location.This algorithm was based on the single-shot object detector based on multi-level feature pyramid network(M2Det)algorithm and replaced the original visual geometry group(VGG)feature extraction network with the ResNet-101 network to improve the feature extraction capability of the network model.By introducing a depth feature matching algorithm,the algorithm shares neural network weights and realizes the design of UAV target recognition and a multi-modal image-matching fusion positioning algorithm.When the reference image and the real-time image were mismatched,the dynamic adaptive proportional constraint and the random sample consensus consistency algorithm(DAPC-RANSAC)were used to optimize the matching results to improve the correct matching efficiency of the target.Using the multi-modal registration data set,the proposed algorithm was compared and analyzed to verify its superiority and feasibility.The results show that the algorithm proposed in this paper can effectively deal with the matching between multi-modal images(visible image–infrared image,infrared image–satellite image,visible image–satellite image),and the contrast,scale,brightness,ambiguity deformation,and other changes had good stability and robustness.Finally,the effectiveness and practicability of the algorithm proposed in this paper were verified in an aerial test scene of an S1000 sixrotor UAV.展开更多
Photoelectrochemical reduction of CO_(2)to produce CO with metal-organic frameworks(MOFs)is recognized as a desirable technology to mitigate CO_(2)emission and generate sustainable energy.To achieve highly efficient e...Photoelectrochemical reduction of CO_(2)to produce CO with metal-organic frameworks(MOFs)is recognized as a desirable technology to mitigate CO_(2)emission and generate sustainable energy.To achieve highly efficient electrocatalyst,it is essential to design a new material interface and uncover new reaction mechanisms or kinetics.Herein,we developed two metal-organic Cu-MOF and Bi-MOF layers using benzene tricarboxylic acid(H_(3)BTC)ligands on CuBi_(2)O_(4) photocathodes.Both MOF layers drastically improved the photoelectrochemical stability by suppressing the photo-corrosion through conformal surface passivation.The Cu-MOF modified CuBi_(2)O_(4) showed more significant charge separation and transfer efficiencies than the Bi-MOF modified control.Based on the transient photocurrent curves under the applied potential of 0.6 V vs.RHE,the rate-law analysis showed the CO_(2)photoreduction took place through a first-order reaction.Further,the photoelectrochemical impedance spectra(PEIS)revealed this reaction order,representing an“operando”analysis.Moreover,the reaction rate constant on Cu-MOF modified sample was higher than that on Bi-MOF modified one and bare CuBi_(2)O_(4).Combined with the density functional theory calculation,the surface absorption of CO_(2)and CO molecules and the higher energy barrier for*COOH intermediates could significantly determine the first order reaction.展开更多
Three copper wares of Han Dynasty, decorated with golden and silvery pattems in Chongqing Municipal, Three Gorges Region, were analyzed by SEM (scanning electron microscope) and EDAX (energy dispersive X-ray analy...Three copper wares of Han Dynasty, decorated with golden and silvery pattems in Chongqing Municipal, Three Gorges Region, were analyzed by SEM (scanning electron microscope) and EDAX (energy dispersive X-ray analysis). The results reveal that mercury was used to melt gold or silver to form amalgam as late as Chinese Han Dynasty. Ancient craftsmen sheared gold foils to attain tiny gold trips that make them easy to melt into liquid mercury. After gilded, artefacts were well polished to show the brilliance of gold. As an important discovery, the silver amalgam was also detected on one copper ware. It is worth noting that silver was mixed with gold in liquid mercury to form silver amalgam which is apt to form amalgam and make silver amalgam layer stick to bronze surface tightly. This successful technology is derived from a prolonged accumulation of Chinese craftsmen on mining and metallurgical handicraft,展开更多
Performance analysis is very important in the study and design of scene matching algorithm. Based on the analysis of the common performance parameters, robustness of scene matching algorithm is defined, including the ...Performance analysis is very important in the study and design of scene matching algorithm. Based on the analysis of the common performance parameters, robustness of scene matching algorithm is defined, including the definitions of robust stability and robust performance, and the corresponding evaluation parameters matching margin and matching adaptability are given. With application of these robustness parameters on 8 scene matching algorithms, quantitative analysis results of algorithm robustness are obtained. The paper provides an important theoretical reference to the performance evaluation of scene matching algorithm.展开更多
Dual-channel redox reaction system is advantageous for photocatalytic hydrogen(H_(2))production when coupled with photoreforming oxidation of waste materials,benefiting both thermodynamically and kinetically.However,e...Dual-channel redox reaction system is advantageous for photocatalytic hydrogen(H_(2))production when coupled with photoreforming oxidation of waste materials,benefiting both thermodynamically and kinetically.However,existing reviews primarily focus on specific oxidation reactions,such as oxidative organic synthesis and water remediation,often neglecting recent advancements in plastic upgrading,biomass conversion,and H_(2)O_(2)production,and failing to provide an in-depth discussion of catalytic mechanisms.This review addresses these gaps by offering a comprehensive overview of recent advancements in dual-channel redox reactions for photocatalytic H_(2)-evolution and waste photoreforming.It highlights waste-to-wealth design concepts,examines the challenges,advantages and diverse applications of dual-channel photocatalytic reactions,including photoreforming of biomass,alcohol,amine,plastic waste,organic pollutants,and H_(2)O_(2)production.Emphasizing improvement strategies and exploration of catalytic mechanisms,it includes advanced in-situ characterization,spin capture experiments,and DFT calculations.By identifying challenges and future directions in this field,this review provides valuable insights for designing innovative dual-channel photocatalytic systems.展开更多
Sustainable development and continued prosperity of humanity hinge on the availability of renewable energy sources on a terawatts scale. In the long run, solar energy is the only source that can meet this daunting dem...Sustainable development and continued prosperity of humanity hinge on the availability of renewable energy sources on a terawatts scale. In the long run, solar energy is the only source that can meet this daunting demand. Widespread utilization of solar energy faces challenges as a result of its diffusive (hence low energy density) and intermittent nature. How to effectively harvest, concentrate, store and redistribute solar energy constitutes a fundamental challenge that the scientific community needs to address. Photoelectrochemical (PEC) water splitting is a process that can directly convert solar energy into chemical energy and store it in chemical bonds, by producing hydrogen as a clean fuel source. It has received significant research attention lately. Here we provide a concise review of the key issues encountered in carrying out PEC water splitting. Our focus is on the balance of considerations such as stability, earth abundance, and efficiency. Particular attention is paid to the combination of photoelectrodes with electrocatalysts, especially on the interfaces between different components.展开更多
Water oxidation,an essential step in photosynthesis,has attracted intense research attention.Understanding the reaction pathways at the electrocatalyst/water interface is of great importance for the development of wat...Water oxidation,an essential step in photosynthesis,has attracted intense research attention.Understanding the reaction pathways at the electrocatalyst/water interface is of great importance for the development of water oxidation catalysts.How the water is oxidized on the electrocatalyst surface by the positive charges is still an open question.This review summarizes current advances in studies on surface chemistry within the context of water oxidation,including the intermediates,reaction mechanisms,and their influences on the reaction kinetics.The Tafel analyses of some electrocatalysts and the rate-laws relative to charge consumption rates are also presented.Moreover,how the multiple charge transfer relies on the intermediate coverage and the accumulated charge numbers is outlined.Lastly,the intermediates and rate-determining steps on some water oxidation catalysts are discussed based on density functional theories.展开更多
Natural gas is an essential chemical raw material and a promising clean energy source,which is widely used and increasingly in demand.Gas separation processes significantly impact the current needs of human society.Th...Natural gas is an essential chemical raw material and a promising clean energy source,which is widely used and increasingly in demand.Gas separation processes significantly impact the current needs of human society.The traditional low temperature liquefaction distillation method of natural gas has high cost of gas separation and purification,which limits its wide application.As a new kind of porous materials,metal-organic frameworks(MOFs)have shown excellent gas separation and purification prospects due to their ultra-high specific surface area,easily modified pore surface,structural design,and functionalization.Here,we summarize the recent research progress of using MOFs adsorbent for the separation of natural gas,including C_(3)H_(8)/CH_(4),C_(2)H_(6)/CH_(4),H_(2)S/CH_(4),CO_(2)/CH_(4),and CH_(4)/N_(2).Furthermore,bottlenecks and possible research directions for further exploration are discussed.展开更多
Both bismuth and copper are non-toxic and earth-abundant elements suitable for lead-free halide perovskite-like photovoltaic devices. Here, we report a highly facile route for in-situ producing copper-bismuth-iodide(C...Both bismuth and copper are non-toxic and earth-abundant elements suitable for lead-free halide perovskite-like photovoltaic devices. Here, we report a highly facile route for in-situ producing copper-bismuth-iodide(CuBiI4) thin films directly on ITO substrate at room temperature, by utilizing a Bi-Cu alloy layer as precursor. X-ray diffraction and transmission electron microscopy(TEM) results verified the formation of well crystallized CuBiI4 thin films with [222] orientation. The transient photovoltage(TPV) analysis revealed that the CuBiI4 is an n-type semiconductor with a suitable band gap of ~1.81 eV, preferable to photoelectric conversion compared with CH3NH3PbI3. It is very interesting that the subsequent spin-coating process of the classical Spiro-MeOTAD organic solution with TBP and acetonitrile resulted in a dense and smooth CuBiI4:SpiroMeOTAD bulk-heterojunction film. The preliminarily fabricated simple sandwich structures of ITO/CuBiI4:Spiro-MeOTAD/Au hybrid solar cell devices displayed efficient photovoltaic performance with the PCE up to 1.119% of the best sample. The room temperature direct metal surface elemental reaction(DMSER) method may provide a new insight for all-inorganic lead free perovskite-like AaBbXx compounds and high performance photovoltaic devices.展开更多
This study evaluated the effect of dietary taurine levels on growth,serum biochemical parameters,salinity adaptability,and antioxidant activity of rainbow trout(Oncorhynchus mykiss).Four diets were formulated with tau...This study evaluated the effect of dietary taurine levels on growth,serum biochemical parameters,salinity adaptability,and antioxidant activity of rainbow trout(Oncorhynchus mykiss).Four diets were formulated with taurine supplements at 0,0.5,1,and 2%w/v(abbreviated as To,T05,Tt,and T2,respectively).Rainbow trouts(initial weight of 80.09±4.72 g)were stocked in tanks(180 L capacity),and were fed these diets for six weeks and subsequently underwent salinity acclimation.Physiological indicators were determined before salinity acclimation at 1,4,7,and 14 days afterwards.Results showed that there were no significant differences in growth performance(final mean weight ranged from 182.35 g to 198.48 g;percent weight gain was between 127.68%and 147.92%)of rainbow trout in freshwater stage,but dietary taurine supplement significantly increased serum-free taurine content.After entering seawater,the Na+-K+-ATPase activity of T2 group returned to its freshwater levels,and the serum cortisol content was significantly higher than To and To 5 groups.At the end of this experiment,the liver superoxide dismutase activity in the To and To 5 groups was significantly lower than in the Tj and T2 groups,and the liver catalase in the To group was the lowest whereas that in the T2 group was the highest.Muscle malondialdehyde content was the highest in the To group,and the lowest in the T2 group.Based on the results of this study,supplement of dietary taurine(0.5-2%)enhanced the salinity tolerance in rainbow trout,which increased with the higher taurine concentration.展开更多
All-inorganic CsPbI_(2)Br perovskite with suitable bandgap and excellent thermal stability has been reported as the most promising candidate for efficient perovskite solar cells (PSCs). However, the high annealing tem...All-inorganic CsPbI_(2)Br perovskite with suitable bandgap and excellent thermal stability has been reported as the most promising candidate for efficient perovskite solar cells (PSCs). However, the high annealing temperature (> 250 ℃) and poor stability of α-CsPbI_(2)Br greatly limit the future application in photovoltaic field. Herein, a facile method is reported to prepare α-CsPbI_(2)Br perovskite film with high stability at low temperature (70 ℃) by incorporating a small amount of γ-aminobutyric acid (GABA) in the precursor solutions. The devices exhibit reproducible photovoltaic performance with a champion efficiency up to 15.16%, along with the excellent stability, maintaining more than 80% of its initial efficiency after stored in ambient condition for 600 h without any encapsulation. Most importantly, the method enables fabrication of semitransparent CsPbI_(2)Br PSCs with a PCE of 6.76%, as well as an average visible transparency (AVT) of 25.38%. To the best of our knowledge, this is the first attempt to apply CsPbI_(2)Br to the semitransparent solar cells.展开更多
基金supported in part by the National Natural Science Foundation of China(Grant No.62276274)Shaanxi Natural Science Foundation(Grant No.2023-JC-YB-528)Chinese aeronautical establishment(Grant No.201851U8012)。
文摘The automatic stealth task of military time-sensitive targets plays a crucial role in maintaining national military security and mastering battlefield dynamics in military applications.We propose a novel Military Time-sensitive Targets Stealth Network via Real-time Mask Generation(MTTSNet).According to our knowledge,this is the first technology to automatically remove military targets in real-time from videos.The critical steps of MTTSNet are as follows:First,we designed a real-time mask generation network based on the encoder-decoder framework,combined with the domain expansion structure,to effectively extract mask images.Specifically,the ASPP structure in the encoder could achieve advanced semantic feature fusion.The decoder stacked high-dimensional information with low-dimensional information to obtain an effective mask layer.Subsequently,the domain expansion module guided the adaptive expansion of mask images.Second,a context adversarial generation network based on gated convolution was constructed to achieve background restoration of mask positions in the original image.In addition,our method worked in an end-to-end manner.A particular semantic segmentation dataset for military time-sensitive targets has been constructed,called the Military Time-sensitive Target Masking Dataset(MTMD).The MTMD dataset experiment successfully demonstrated that this method could create a mask that completely occludes the target and that the target could be hidden in real time using this mask.We demonstrated the concealment performance of our proposed method by comparing it to a number of well-known and highly optimized baselines.
基金Supported by the National Natural Science Foundation of China(21176028 and21506011)the National Science Fund for Distinguished Young Scholars of China(21425624)Doctoral Fund of Ministry of Education of China(20121101110050)
文摘Glycyrrhetic acid 3-O-mono-β-D-glucuronide (GAMG), the major functional ingredient in licorice, has widespread applications in food, pharmacy and cosmetics industry. The production of GAMG through Penicillium purpurogenum Li-3 cultivation was for the first time performed through both batch and fed-batch processes in bioreactors. In batch process, under optimal conditions (pH 5.0, temperature 32℃, agitation speed 100 r. rain 1), 3.55 g. L^-1 GAMG was obtained in a 2.5 L fermentor. To further enhance GAMG production, a fine fed-batch process was developed by using pH and DO as feedback parameters. Starting from 48 h, 100 m190 g-L 1 substrate Glycyrrhizin (GL) was fed each time when pH increased to above 5.0 and DO was increased to above 80%. This strategy can significantly enhance GAMG production: the achieved GL conversion was 95.34% with GAMG yield of 95.15%, and GAMG concentration was 16.62 g. L^-1 which was 5 times higher than that of batch. Then, a two-step separation strat- egy was established to separate GAMG from fermentation broth by crude extraction of 15 ml column packed with D10I resin followed by fine purification with preparative C18 chromatography. The obtained GAMG purity was 95.79%. This study provides a new insight into the industrial bioprocess of high-level GAMG production.
基金the financial support provided by National Natural Science Foundation of China (22008163)Postgraduate Research & Practice Innovation Program of Jiangsu Province+2 种基金Open Project Program of the State Key Laboratory of Photocatalysis on Energy and Environment (SKLPEE-KF202309)Natural Science Research Project of Higher Education Institutions in Jiangsu Province (20KJB150042, 21KJB150038)Natural Science Foundation of Jiangsu Province (BK20231342, BK20210867)。
文摘Carbon dioxide reduction reaction(CO_(2)RR) represents an efficient approach to achieving carbon neutrality and simultaneously generating clean energy.However,the strong stability of CO_(2) molecules and the diversity of products pose significant challenges.As an emerging material,bimetallic catalysts have been widely reported for their unique advantages,such as tunable electronic structures,suitable adsorption/desorption of CO_(2) and intermediates,and optimizable d-band centers of active sites through bimetallic synergy.These catalysts provide a remarkable platform for converting CO_(2) into high value-added chemicals.This review comprehensively summarizes recent research advances in bimetallic catalysts for CO_(2)RR.Firstly,the challenges associated with CO_(2)RR,including activity and selectivity are analyzed,followed by a discussion on the unique advantages of bimetallic catalysts.Next,their synthesis strategies are categorized into dual-atom site catalysts(DACs),bimetallic nanoparticles and nanoclusters,binary metal semiconductors,and layered double hydroxides(LDHs).Additionally,advanced characterization techniques of bimetallic catalysts and their applications in CO_(2)RR are thoroughly introduced.Finally,the prospects and challenges for the application of bimetallic materials are highlighted.This review aims to provide inspiration for CO_(2)RR into high-value chemicals and shed light on the research of bimetallic materials.
基金supported in part by the National Natural Science Foundation of China under Grant 62276274in part by the Natural Science Foundation of Shaanxi Province under Grant 2020JM-537,and in part by the Aeronautical Science Fund under Grant 201851U8012(corresponding author:Xiaogang Yang).
文摘In recent years,many visual positioning algorithms have been proposed based on computer vision and they have achieved good results.However,these algorithms have a single function,cannot perceive the environment,and have poor versatility,and there is a certain mismatch phenomenon,which affects the positioning accuracy.Therefore,this paper proposes a location algorithm that combines a target recognition algorithm with a depth feature matching algorithm to solve the problem of unmanned aerial vehicle(UAV)environment perception and multi-modal image-matching fusion location.This algorithm was based on the single-shot object detector based on multi-level feature pyramid network(M2Det)algorithm and replaced the original visual geometry group(VGG)feature extraction network with the ResNet-101 network to improve the feature extraction capability of the network model.By introducing a depth feature matching algorithm,the algorithm shares neural network weights and realizes the design of UAV target recognition and a multi-modal image-matching fusion positioning algorithm.When the reference image and the real-time image were mismatched,the dynamic adaptive proportional constraint and the random sample consensus consistency algorithm(DAPC-RANSAC)were used to optimize the matching results to improve the correct matching efficiency of the target.Using the multi-modal registration data set,the proposed algorithm was compared and analyzed to verify its superiority and feasibility.The results show that the algorithm proposed in this paper can effectively deal with the matching between multi-modal images(visible image–infrared image,infrared image–satellite image,visible image–satellite image),and the contrast,scale,brightness,ambiguity deformation,and other changes had good stability and robustness.Finally,the effectiveness and practicability of the algorithm proposed in this paper were verified in an aerial test scene of an S1000 sixrotor UAV.
基金supported by the National Natural Science Foundation of China(Project.U1604121)and Startup funding from Suzhou University of Science and Technology.
文摘Photoelectrochemical reduction of CO_(2)to produce CO with metal-organic frameworks(MOFs)is recognized as a desirable technology to mitigate CO_(2)emission and generate sustainable energy.To achieve highly efficient electrocatalyst,it is essential to design a new material interface and uncover new reaction mechanisms or kinetics.Herein,we developed two metal-organic Cu-MOF and Bi-MOF layers using benzene tricarboxylic acid(H_(3)BTC)ligands on CuBi_(2)O_(4) photocathodes.Both MOF layers drastically improved the photoelectrochemical stability by suppressing the photo-corrosion through conformal surface passivation.The Cu-MOF modified CuBi_(2)O_(4) showed more significant charge separation and transfer efficiencies than the Bi-MOF modified control.Based on the transient photocurrent curves under the applied potential of 0.6 V vs.RHE,the rate-law analysis showed the CO_(2)photoreduction took place through a first-order reaction.Further,the photoelectrochemical impedance spectra(PEIS)revealed this reaction order,representing an“operando”analysis.Moreover,the reaction rate constant on Cu-MOF modified sample was higher than that on Bi-MOF modified one and bare CuBi_(2)O_(4).Combined with the density functional theory calculation,the surface absorption of CO_(2)and CO molecules and the higher energy barrier for*COOH intermediates could significantly determine the first order reaction.
文摘Three copper wares of Han Dynasty, decorated with golden and silvery pattems in Chongqing Municipal, Three Gorges Region, were analyzed by SEM (scanning electron microscope) and EDAX (energy dispersive X-ray analysis). The results reveal that mercury was used to melt gold or silver to form amalgam as late as Chinese Han Dynasty. Ancient craftsmen sheared gold foils to attain tiny gold trips that make them easy to melt into liquid mercury. After gilded, artefacts were well polished to show the brilliance of gold. As an important discovery, the silver amalgam was also detected on one copper ware. It is worth noting that silver was mixed with gold in liquid mercury to form silver amalgam which is apt to form amalgam and make silver amalgam layer stick to bronze surface tightly. This successful technology is derived from a prolonged accumulation of Chinese craftsmen on mining and metallurgical handicraft,
文摘Performance analysis is very important in the study and design of scene matching algorithm. Based on the analysis of the common performance parameters, robustness of scene matching algorithm is defined, including the definitions of robust stability and robust performance, and the corresponding evaluation parameters matching margin and matching adaptability are given. With application of these robustness parameters on 8 scene matching algorithms, quantitative analysis results of algorithm robustness are obtained. The paper provides an important theoretical reference to the performance evaluation of scene matching algorithm.
文摘Dual-channel redox reaction system is advantageous for photocatalytic hydrogen(H_(2))production when coupled with photoreforming oxidation of waste materials,benefiting both thermodynamically and kinetically.However,existing reviews primarily focus on specific oxidation reactions,such as oxidative organic synthesis and water remediation,often neglecting recent advancements in plastic upgrading,biomass conversion,and H_(2)O_(2)production,and failing to provide an in-depth discussion of catalytic mechanisms.This review addresses these gaps by offering a comprehensive overview of recent advancements in dual-channel redox reactions for photocatalytic H_(2)-evolution and waste photoreforming.It highlights waste-to-wealth design concepts,examines the challenges,advantages and diverse applications of dual-channel photocatalytic reactions,including photoreforming of biomass,alcohol,amine,plastic waste,organic pollutants,and H_(2)O_(2)production.Emphasizing improvement strategies and exploration of catalytic mechanisms,it includes advanced in-situ characterization,spin capture experiments,and DFT calculations.By identifying challenges and future directions in this field,this review provides valuable insights for designing innovative dual-channel photocatalytic systems.
文摘Sustainable development and continued prosperity of humanity hinge on the availability of renewable energy sources on a terawatts scale. In the long run, solar energy is the only source that can meet this daunting demand. Widespread utilization of solar energy faces challenges as a result of its diffusive (hence low energy density) and intermittent nature. How to effectively harvest, concentrate, store and redistribute solar energy constitutes a fundamental challenge that the scientific community needs to address. Photoelectrochemical (PEC) water splitting is a process that can directly convert solar energy into chemical energy and store it in chemical bonds, by producing hydrogen as a clean fuel source. It has received significant research attention lately. Here we provide a concise review of the key issues encountered in carrying out PEC water splitting. Our focus is on the balance of considerations such as stability, earth abundance, and efficiency. Particular attention is paid to the combination of photoelectrodes with electrocatalysts, especially on the interfaces between different components.
基金X.G.Y.and C.M.L.are supported by the National Natural Science Foundation of China(Nos.U1604121 and 22008163)Natural Science Foundation of Jiangsu Province(No.BK20180103)Jiangsu Laboratory for Biochemical Sensing and Biochip,and Jiangsu Key Laboratory for Micro and Nano Heat Fluid Flow Technology and Energy Application.Y.X.W.and D.W.W.acknowledge the support by the U.S.Department of Energy,Office of Science,Office of Basic Energy Science,Chemical Sciences,Geosciences,and Biosciences Division under Award Number DE-SC0020261.
文摘Water oxidation,an essential step in photosynthesis,has attracted intense research attention.Understanding the reaction pathways at the electrocatalyst/water interface is of great importance for the development of water oxidation catalysts.How the water is oxidized on the electrocatalyst surface by the positive charges is still an open question.This review summarizes current advances in studies on surface chemistry within the context of water oxidation,including the intermediates,reaction mechanisms,and their influences on the reaction kinetics.The Tafel analyses of some electrocatalysts and the rate-laws relative to charge consumption rates are also presented.Moreover,how the multiple charge transfer relies on the intermediate coverage and the accumulated charge numbers is outlined.Lastly,the intermediates and rate-determining steps on some water oxidation catalysts are discussed based on density functional theories.
基金supported by the Natural Science Foundation of Zhejiang Province(LY20E020001).
文摘Natural gas is an essential chemical raw material and a promising clean energy source,which is widely used and increasingly in demand.Gas separation processes significantly impact the current needs of human society.The traditional low temperature liquefaction distillation method of natural gas has high cost of gas separation and purification,which limits its wide application.As a new kind of porous materials,metal-organic frameworks(MOFs)have shown excellent gas separation and purification prospects due to their ultra-high specific surface area,easily modified pore surface,structural design,and functionalization.Here,we summarize the recent research progress of using MOFs adsorbent for the separation of natural gas,including C_(3)H_(8)/CH_(4),C_(2)H_(6)/CH_(4),H_(2)S/CH_(4),CO_(2)/CH_(4),and CH_(4)/N_(2).Furthermore,bottlenecks and possible research directions for further exploration are discussed.
基金supported by the National Natural Science Foundation of China (21673200, 61504117 and U1604121)the Innovation Scientists and Technicians Troop Construction Projects of Henan Province (144200510014)
文摘Both bismuth and copper are non-toxic and earth-abundant elements suitable for lead-free halide perovskite-like photovoltaic devices. Here, we report a highly facile route for in-situ producing copper-bismuth-iodide(CuBiI4) thin films directly on ITO substrate at room temperature, by utilizing a Bi-Cu alloy layer as precursor. X-ray diffraction and transmission electron microscopy(TEM) results verified the formation of well crystallized CuBiI4 thin films with [222] orientation. The transient photovoltage(TPV) analysis revealed that the CuBiI4 is an n-type semiconductor with a suitable band gap of ~1.81 eV, preferable to photoelectric conversion compared with CH3NH3PbI3. It is very interesting that the subsequent spin-coating process of the classical Spiro-MeOTAD organic solution with TBP and acetonitrile resulted in a dense and smooth CuBiI4:SpiroMeOTAD bulk-heterojunction film. The preliminarily fabricated simple sandwich structures of ITO/CuBiI4:Spiro-MeOTAD/Au hybrid solar cell devices displayed efficient photovoltaic performance with the PCE up to 1.119% of the best sample. The room temperature direct metal surface elemental reaction(DMSER) method may provide a new insight for all-inorganic lead free perovskite-like AaBbXx compounds and high performance photovoltaic devices.
基金This study was supported by the National Key Research and Development Program of China(2019 YFD0901000)the National Natural Science Foundation of China(31702364 and U1906206)the OUC-AUBURN Joint Research Center for Aquaculture and Environmental Sciences.
文摘This study evaluated the effect of dietary taurine levels on growth,serum biochemical parameters,salinity adaptability,and antioxidant activity of rainbow trout(Oncorhynchus mykiss).Four diets were formulated with taurine supplements at 0,0.5,1,and 2%w/v(abbreviated as To,T05,Tt,and T2,respectively).Rainbow trouts(initial weight of 80.09±4.72 g)were stocked in tanks(180 L capacity),and were fed these diets for six weeks and subsequently underwent salinity acclimation.Physiological indicators were determined before salinity acclimation at 1,4,7,and 14 days afterwards.Results showed that there were no significant differences in growth performance(final mean weight ranged from 182.35 g to 198.48 g;percent weight gain was between 127.68%and 147.92%)of rainbow trout in freshwater stage,but dietary taurine supplement significantly increased serum-free taurine content.After entering seawater,the Na+-K+-ATPase activity of T2 group returned to its freshwater levels,and the serum cortisol content was significantly higher than To and To 5 groups.At the end of this experiment,the liver superoxide dismutase activity in the To and To 5 groups was significantly lower than in the Tj and T2 groups,and the liver catalase in the To group was the lowest whereas that in the T2 group was the highest.Muscle malondialdehyde content was the highest in the To group,and the lowest in the T2 group.Based on the results of this study,supplement of dietary taurine(0.5-2%)enhanced the salinity tolerance in rainbow trout,which increased with the higher taurine concentration.
基金financial support from the Taishan Scholar Project of Shandong Province (No. tsqn201812098)the Shandong Provincial Natural Science Foundation (Nos. ZR2020MF103,ZR2019MF057 and ZR2019MA066)National Natural Science Foundation of China (No. 21701080)。
文摘All-inorganic CsPbI_(2)Br perovskite with suitable bandgap and excellent thermal stability has been reported as the most promising candidate for efficient perovskite solar cells (PSCs). However, the high annealing temperature (> 250 ℃) and poor stability of α-CsPbI_(2)Br greatly limit the future application in photovoltaic field. Herein, a facile method is reported to prepare α-CsPbI_(2)Br perovskite film with high stability at low temperature (70 ℃) by incorporating a small amount of γ-aminobutyric acid (GABA) in the precursor solutions. The devices exhibit reproducible photovoltaic performance with a champion efficiency up to 15.16%, along with the excellent stability, maintaining more than 80% of its initial efficiency after stored in ambient condition for 600 h without any encapsulation. Most importantly, the method enables fabrication of semitransparent CsPbI_(2)Br PSCs with a PCE of 6.76%, as well as an average visible transparency (AVT) of 25.38%. To the best of our knowledge, this is the first attempt to apply CsPbI_(2)Br to the semitransparent solar cells.