Bacteria play a major role in metabolizing ammonia and other metabolites in recirculating aquaculture systems(RASs).To characterize and compare the bacterial communities in the biofilters of two full-scale RASs for th...Bacteria play a major role in metabolizing ammonia and other metabolites in recirculating aquaculture systems(RASs).To characterize and compare the bacterial communities in the biofilters of two full-scale RASs for the culture of puffer fish,Takifugu rubripes,at different ages and densities were studied.In overall,47807 optimized reads of the 16 S rRNA gene with V4-V5 region were obtained from four biofilm samples collected after biofilm maturation.At 97%cut-off level,these sequences were clustered into 500 operational taxonomic units,and were classified into 19 bacterial phyla and 138 genera.At the phylum level,Proteobacteria and Bacteroidetes were the most abundant,followed by Nitrospirae and Planctomycetes.At the genus level,Colwellia,Marinifilum,Oceanospirillum,Lutibacter,Winogradskyella,Pseudoalteromonas,Arcobacter,and Phaeobacter were the top members.Nitrosomonas and Nitrospira were main ammonia-and nitrite-oxidizing bacteria.Differences in bacterial communities at different sampling dates and similarities of both biofilters were revealed in the Venn diagram and cluster analysis.Maintaining a good water quality and health offarmed fish in RASs depended on the correct management of the bacterial communities.This study provides more accurate information on the bacterial communities associated with the bifilters of both RASs.展开更多
In this work,highly regular TiO_(2)nanorod array films were synthesized in situ on FTO by a facile hydrothermal method,and then ZnO shell layers were grown on the surface of the nanorods to form a coreshell structure ...In this work,highly regular TiO_(2)nanorod array films were synthesized in situ on FTO by a facile hydrothermal method,and then ZnO shell layers were grown on the surface of the nanorods to form a coreshell structure via an ion-layer adsorption-reaction way.Compared to the TiO_(2)nanorods,the prepared TiO_(2)/ZnO nanocomposites exhibited enhanced ethanol sensing performances,including a low working temperature,higher sensitivity,and faster response capability.The optimum sensor based on 2c-TiO_(2)/ZnO exhibited the maximum response value of 30.85 toward 50×10^(-6)C_(2)H_(5)OH at 340℃,which was almost 4.15 times higher than that of the TiO_(2)sensor.The improved ethanol sensing mechanism was discussed in relation to the unique nanorod array structure and the heterojunctions between TiO_(2)and ZnO.展开更多
The morphological characteristics of coarse aggregates, namely shape profile, angularity and surface texture, have a significant effect on the mechanical properties of asphalt mixtures. The identification methods and ...The morphological characteristics of coarse aggregates, namely shape profile, angularity and surface texture, have a significant effect on the mechanical properties of asphalt mixtures. The identification methods and evaluation indexes of the morphological characteristics are crucial for the coarse aggregates. First, the visual identification technologies, including charged coupled device (CCD) image processing, X-ray tomography imaging and laser scanning technology, are summarized in term of the characteristics, research status and existing problems. Based on the deficiencies of visual identification technologies, it is proposed to improve the three-dimensional reconstruction of aggregate particles by increasing the number of two-dimensional projection directions or scanning sections. Moreover, the evaluation indexes of coarse aggregate morphology were summarized from the three aspects, namely shape profile, angularity and surface texture. It is found that evaluation of the indexes based on two-dimensional profile images or unrelated to pavement performance could not adequately evaluate the morphological characteristics of coarse aggregates. Therefore, the evaluation methods and indexes of coarse aggregate morphological characteristics have been recommended based on the performance of asphalt mixtures in this paper, which is helpful to establish a complete set of an evaluation system for coarse aggregate morphology.展开更多
The timely and effective detection of CO and CH_(4) is critical as the explosion and poisoning of them can bring serious potential risks to coal mining.In this study,combining metal oxide semiconductors with noble met...The timely and effective detection of CO and CH_(4) is critical as the explosion and poisoning of them can bring serious potential risks to coal mining.In this study,combining metal oxide semiconductors with noble metals offers a promising route to achieve this target.Hierarchical porous Pd modified In_(2)O_(3) nanoflowers were prepared via two-step hydrothermal method and exhibited dual detection of CO and CH_(4) at different temperatures.The material has been characterized by a number of advanced techniques and the results indicate that Pd modified In_(2)O_(3) are hierarchical porous nanoflowers structure consisting of pores of approximately 1.8 nm in size.The sensing properties results show that the Pd modified In_(2)O_(3) based sensor exhibits temperature-dependent dual selectivity detection of CO at 280℃ and CH_(4) at 340℃.In addition,the Pd modified In_(2)O_(3) sensor display higher sensing response of CO(5.824 for 100 ppm)and CH_(4)(1.162 for 1000 ppm),fast response and recovery time,as well as good repeatability,which demonstrating the great potential for practical application.Such good gas-sensing performance are mainly attributed to the unique flower-like structure,the presence of porosity on the sample surface,and the catalytic effect of Pd.展开更多
Realizing the real-time detection of CH4 is important for the safety of human life.A facile hydrothermal method was used to synthesize Ag nanoparticlesdecorated ZnO porous nanoflakes(PNFs)in this study.The characteriz...Realizing the real-time detection of CH4 is important for the safety of human life.A facile hydrothermal method was used to synthesize Ag nanoparticlesdecorated ZnO porous nanoflakes(PNFs)in this study.The characterization results confirmed that Ag nanoparticles had been decorated in ZnO nanoflakes with the thickness of~10 nm.The gas-sensing properties of Ag-decorated ZnO nanoflakes were also investigated.While the gas-sensing performances of ZnO were remarkably improved by decorating Ag nanoparticles on the surface of ZnO nanoflakes,the response of the Agdecorated ZnO sensor to 3000 ppm CH4 is almost 1.3 times as high as that of pristine ZnO sensor.The obtained Ag/ZnO sensor exhibits better long-term stability and shorter response recovery time(5/38 s)in the comparison with pristine ZnO,demonstrating the possibility for the actual detection of CH4.The enhanced CH4 sensing performance can be attributed to the synergism between the unique hierarchical porous structure and the sensitizing actions utilized by the Ag nanoparticles.展开更多
基金Supported by the National Key R&D Program of China(No.2017YFD0701700)National Natural Science Foundation of China(Nos.31472312,31672673)。
文摘Bacteria play a major role in metabolizing ammonia and other metabolites in recirculating aquaculture systems(RASs).To characterize and compare the bacterial communities in the biofilters of two full-scale RASs for the culture of puffer fish,Takifugu rubripes,at different ages and densities were studied.In overall,47807 optimized reads of the 16 S rRNA gene with V4-V5 region were obtained from four biofilm samples collected after biofilm maturation.At 97%cut-off level,these sequences were clustered into 500 operational taxonomic units,and were classified into 19 bacterial phyla and 138 genera.At the phylum level,Proteobacteria and Bacteroidetes were the most abundant,followed by Nitrospirae and Planctomycetes.At the genus level,Colwellia,Marinifilum,Oceanospirillum,Lutibacter,Winogradskyella,Pseudoalteromonas,Arcobacter,and Phaeobacter were the top members.Nitrosomonas and Nitrospira were main ammonia-and nitrite-oxidizing bacteria.Differences in bacterial communities at different sampling dates and similarities of both biofilters were revealed in the Venn diagram and cluster analysis.Maintaining a good water quality and health offarmed fish in RASs depended on the correct management of the bacterial communities.This study provides more accurate information on the bacterial communities associated with the bifilters of both RASs.
基金the Youth Project of Henan Natural Science Foundation(212300410149)the National Natural Science Foundation of China(62101177)the Key Scientific Research Project of Colleges and University in Henan Province(21A430019).
文摘In this work,highly regular TiO_(2)nanorod array films were synthesized in situ on FTO by a facile hydrothermal method,and then ZnO shell layers were grown on the surface of the nanorods to form a coreshell structure via an ion-layer adsorption-reaction way.Compared to the TiO_(2)nanorods,the prepared TiO_(2)/ZnO nanocomposites exhibited enhanced ethanol sensing performances,including a low working temperature,higher sensitivity,and faster response capability.The optimum sensor based on 2c-TiO_(2)/ZnO exhibited the maximum response value of 30.85 toward 50×10^(-6)C_(2)H_(5)OH at 340℃,which was almost 4.15 times higher than that of the TiO_(2)sensor.The improved ethanol sensing mechanism was discussed in relation to the unique nanorod array structure and the heterojunctions between TiO_(2)and ZnO.
基金supported by the Special Fund for Basic Scientific Research of Central College of Chang’an University(Nos.300102218413,310821153502 and 300102218405)the Department of Science and Technology of Shaanxi Province(Nos.2016 ZDJC-24 and 2017KCT-13)the Scientific Innovation Practice Project of Postgraduates of Chang’an University(No.300111004002)
文摘The morphological characteristics of coarse aggregates, namely shape profile, angularity and surface texture, have a significant effect on the mechanical properties of asphalt mixtures. The identification methods and evaluation indexes of the morphological characteristics are crucial for the coarse aggregates. First, the visual identification technologies, including charged coupled device (CCD) image processing, X-ray tomography imaging and laser scanning technology, are summarized in term of the characteristics, research status and existing problems. Based on the deficiencies of visual identification technologies, it is proposed to improve the three-dimensional reconstruction of aggregate particles by increasing the number of two-dimensional projection directions or scanning sections. Moreover, the evaluation indexes of coarse aggregate morphology were summarized from the three aspects, namely shape profile, angularity and surface texture. It is found that evaluation of the indexes based on two-dimensional profile images or unrelated to pavement performance could not adequately evaluate the morphological characteristics of coarse aggregates. Therefore, the evaluation methods and indexes of coarse aggregate morphological characteristics have been recommended based on the performance of asphalt mixtures in this paper, which is helpful to establish a complete set of an evaluation system for coarse aggregate morphology.
基金This work is supported by the National Natural Science Foundation of China(U1704255,62101177)the fellowship of China Postdoctoral Science Foundation(2021M690919)+1 种基金Youth Project of Natural Science Foundation of Henan Province(212300410149)the Key Scientific Research Project of Colleges and University in Henan Province(21A430019).
文摘The timely and effective detection of CO and CH_(4) is critical as the explosion and poisoning of them can bring serious potential risks to coal mining.In this study,combining metal oxide semiconductors with noble metals offers a promising route to achieve this target.Hierarchical porous Pd modified In_(2)O_(3) nanoflowers were prepared via two-step hydrothermal method and exhibited dual detection of CO and CH_(4) at different temperatures.The material has been characterized by a number of advanced techniques and the results indicate that Pd modified In_(2)O_(3) are hierarchical porous nanoflowers structure consisting of pores of approximately 1.8 nm in size.The sensing properties results show that the Pd modified In_(2)O_(3) based sensor exhibits temperature-dependent dual selectivity detection of CO at 280℃ and CH_(4) at 340℃.In addition,the Pd modified In_(2)O_(3) sensor display higher sensing response of CO(5.824 for 100 ppm)and CH_(4)(1.162 for 1000 ppm),fast response and recovery time,as well as good repeatability,which demonstrating the great potential for practical application.Such good gas-sensing performance are mainly attributed to the unique flower-like structure,the presence of porosity on the sample surface,and the catalytic effect of Pd.
基金the National Natural Science Foundation of China(U1704255,62101177)the fellowship of China Postdoctoral Science Foundation(2021M690919)+1 种基金the Youth Project of Natural Science Foundation of Henan Province(212300410149)the Key Scientific Research Project of Colleges and University in Henan Province(21A430019).
文摘Realizing the real-time detection of CH4 is important for the safety of human life.A facile hydrothermal method was used to synthesize Ag nanoparticlesdecorated ZnO porous nanoflakes(PNFs)in this study.The characterization results confirmed that Ag nanoparticles had been decorated in ZnO nanoflakes with the thickness of~10 nm.The gas-sensing properties of Ag-decorated ZnO nanoflakes were also investigated.While the gas-sensing performances of ZnO were remarkably improved by decorating Ag nanoparticles on the surface of ZnO nanoflakes,the response of the Agdecorated ZnO sensor to 3000 ppm CH4 is almost 1.3 times as high as that of pristine ZnO sensor.The obtained Ag/ZnO sensor exhibits better long-term stability and shorter response recovery time(5/38 s)in the comparison with pristine ZnO,demonstrating the possibility for the actual detection of CH4.The enhanced CH4 sensing performance can be attributed to the synergism between the unique hierarchical porous structure and the sensitizing actions utilized by the Ag nanoparticles.