A pilot-scale multilevel contact oxidation reactors system, coupled with saran lock carriers,was applied for the treatment of poultry farm wastewater. The removal efficiencies of CODcr, ammonia, and the total nitrogen...A pilot-scale multilevel contact oxidation reactors system, coupled with saran lock carriers,was applied for the treatment of poultry farm wastewater. The removal efficiencies of CODcr, ammonia, and the total nitrogen as well as the elimination performance of CODcr and total nitrogen along the three-level contact oxidation tanks under six designed operational models were investigated. Based on the performance of the nitrogen removal of the saran lock carriers and the distribution of anoxic–aerobic interspace under the suitable operation model, the mechanism of nitrogen removal of the system was also explored. The results revealed that the intermittent aeration under parallel model is the most suitable operation model, while the removal efficiencies of CODcr, ammonia, and the total nitrogen were 86.86%, 84.04%, and 80.96%, respectively. The effluent concentration of CODcr,ammonia, and the total nitrogen were 55.6 mg/L, 8.3 mg/L, and 12.0 mg/L, which satisfy both the discharge standard of pollutants for livestock and poultry breeding industry(GB18596–2001) and the first grade of the integrated wastewater discharge standard(GB 8978–1996). Moreover, the mechanism for the nitrogen removal should be attributed to the plenty of anoxic–aerobic interspaces of the biofilm and the three-dimensional spiral structure of the saran lock carriers, where the oxygen-deficient distribution was suitable for the happening of the simultaneous nitrification and denitrification process. Therefore, the multilevel contact oxidation tanks system is an effective pathway for the treatment of the poultry farm wastewater on the strength of a suitable operation model and novel carriers.展开更多
Metal oxide hollow structures with multilevel interiors are of great interest for potential applications such as catalysis, chemical sensing, drug delivery, and energy storage. However, the controlled synthesis of mul...Metal oxide hollow structures with multilevel interiors are of great interest for potential applications such as catalysis, chemical sensing, drug delivery, and energy storage. However, the controlled synthesis of multilevel nanotubes remains a great challenge. Here we develop a facile interface-modulated approach toward the synthesis of complex metal oxide multilevel nanotubes with tunable interior structures through electrospinning followed by controlled heat treatment. This versatile strategy can be effectively applied to fabricate wire-in-tube and tube- in-tube nanotubes of various metal oxides. These multilevel nanotubes possess a large specific surface area, fast mass transport, good strain accommodation, and high packing density, which are advantageous for lithium-ion batteries （LIBs） and the oxygen reduction reaction （ORR）. Specifically, shrinkable CoMn204 tube-in-tube nanotubes as a lithium-ion battery anode deliver a high discharge capacity of -565 mAh-g-1 at a high rate of 2 A.g-~, maintaining 89% of the latter after 500 cycles. Further, as an oxygen reduction reaction catalyst, these nanotubes also exhibit excellent stability with about 92% current retention after 30,000 s, which is higher than that of commercial Pt/C （81%）. Therefore, this feasible method may push the rapid development of one-dimensional （1D） nanomaterials. These multifunctional nanotubes have great potential in many frontier fields.展开更多
A lab-scale integrated treatment system including the novel sequence bio-ecological process （SBEP） and biological aerated filter （BAF） for a sewage mixture （chemistry laboratory wastewater and domestic sewage） w...A lab-scale integrated treatment system including the novel sequence bio-ecological process （SBEP） and biological aerated filter （BAF） for a sewage mixture （chemistry laboratory wastewater and domestic sewage） was presented in this paper. The main objective of the study was to test the contribution of artificial aeration, recir-culation ratio and mass concentration of steel slag on pollutant removal in winter when the plants are dormant. It had been shown that SBEP and BAF play different roles in removing contaminants from wastewater. During the airflow experiment, the removal efficiency of COD and TP in SBEP was higher than that in BAF, whereas BAF can compensate for the deficiency of SBEP where no significant improvement on ammonium nitrogen removal is ob-served. Yet, the removal etticiencies of COD,TP and NH4^＋ -N in SBEP could be improved apparently when ditterent recireulation ratio or various mass concentration of steel were applied. Especially, when the airflow of 0.06 L·h^-1, the recirculation ratio rate of 80% and the mass concentration of steel of 2.2-2.4 g·L^-1 were applied, thehighest efficiency of 94.6%, 77.9% and 80.7% for COD, TP and NH4^＋ -N were achieved,-respectively,The integrated treatment system of SBEP and BAF was proved to be an effective wastewater treatment technique and a better alternative to treat domestic sewage.展开更多
Highly repeatable multilevel bipolar resistive switching in Ti/Ce Ox/Pt nonvolatile memory device has been demonstrated. X-ray diffraction studies of Ce O2 films reveal the formation of weak polycrystalline structure....Highly repeatable multilevel bipolar resistive switching in Ti/Ce Ox/Pt nonvolatile memory device has been demonstrated. X-ray diffraction studies of Ce O2 films reveal the formation of weak polycrystalline structure. The observed good memory performance, including stable cycling endurance and long data retention times（〉10^4s） with an acceptable resistance ratio（～10^2）, enables the device for its applications in future non-volatile resistive random access memories（RRAMs）. Based on the unique distribution characteristics of oxygen vacancies in Ce Ox films, the possible mechanism of multilevel resistive switching in Ce Ox RRAM devices has been discussed. The conduction mechanism in low resistance state is found to be Ohmic due to conductive filamentary paths, while that in the high resistance state was identified as Ohmic for low applied voltages and a space-charge-limited conduction dominated by Schottky emission at high applied voltages.展开更多
Multilevel resistive switching(RS)is a key property to embrace the full potential of memristive devices for non-volatile memory and neuromorphic computing applications.In this study,we employed nanoparticulated cobalt...Multilevel resistive switching(RS)is a key property to embrace the full potential of memristive devices for non-volatile memory and neuromorphic computing applications.In this study,we employed nanoparticulated cobaltite oxide(Co_(3)O_(4))as a model material to demonstrate the multilevel RS and synaptic learning capabilities because of its multiple and stable redox state properties.The Pt/Co_(3)O_(4)/Pt memristive device exhibited tunable RS properties with respect to different voltages and compliance currents(CC)without the electroforming process.That is,the device showed voltage-dependent RS at a higher CC whereas CC-dependent RS was observed at lower CC.The device showed four different resistance states during endurance and retention measurements and non-volatile memory results indicated that the CC-based measurement had less variation.Besides,we investigated the basic and complex synaptic plasticity properties using the analog current-voltage characteristics of the Pt/Co_(3)O_(4)/Pt device.In particular,we mimicked the potentiation–depression and four-spike time-dependent plasticity(STDP)rules such as asymmetric Hebbian,asymmetric anti-Hebbian,symmetric Hebbian,and symmetric antiHebbian learning rules.The results of the present work indicate that the cobaltite oxide is an excellent nanomaterial for both multilevel RS and neuromorphic computing applications.展开更多
During brewery wastewater treatment by a hydrolyzation-food chain reactor(FCR)system,sludge was recycled to the anaerobic segment.With the function of hydrolyzation acidification in the anaerobic segment and the proce...During brewery wastewater treatment by a hydrolyzation-food chain reactor(FCR)system,sludge was recycled to the anaerobic segment.With the function of hydrolyzation acidification in the anaerobic segment and the processes of aerobic oxidation and antagonism,preda-tion,interaction and symbiosis among microbes in multi-level oxidation segment,residual sludge could be reduced effectively.The 6-month dynamic experiments show that the average chemical oxygen demand(COD)removal ratio was 92.6% and average sludge production of the aerobic segment was 8.14%,with the COD of the influent at 960–1720 mg/L and hydraulic retention time(HRT)of 12 h.Since the producedsludge could be recycled and hydrolyzed in the anaerobic segment,no excess sludge was produced during the steady running for this system.展开更多
基金supported of the Major Science and Technology Program for Water Pollution Control and Treatment(Nos.2017ZX07102004-002 and 2012ZX07201002-6)
文摘A pilot-scale multilevel contact oxidation reactors system, coupled with saran lock carriers,was applied for the treatment of poultry farm wastewater. The removal efficiencies of CODcr, ammonia, and the total nitrogen as well as the elimination performance of CODcr and total nitrogen along the three-level contact oxidation tanks under six designed operational models were investigated. Based on the performance of the nitrogen removal of the saran lock carriers and the distribution of anoxic–aerobic interspace under the suitable operation model, the mechanism of nitrogen removal of the system was also explored. The results revealed that the intermittent aeration under parallel model is the most suitable operation model, while the removal efficiencies of CODcr, ammonia, and the total nitrogen were 86.86%, 84.04%, and 80.96%, respectively. The effluent concentration of CODcr,ammonia, and the total nitrogen were 55.6 mg/L, 8.3 mg/L, and 12.0 mg/L, which satisfy both the discharge standard of pollutants for livestock and poultry breeding industry(GB18596–2001) and the first grade of the integrated wastewater discharge standard(GB 8978–1996). Moreover, the mechanism for the nitrogen removal should be attributed to the plenty of anoxic–aerobic interspaces of the biofilm and the three-dimensional spiral structure of the saran lock carriers, where the oxygen-deficient distribution was suitable for the happening of the simultaneous nitrification and denitrification process. Therefore, the multilevel contact oxidation tanks system is an effective pathway for the treatment of the poultry farm wastewater on the strength of a suitable operation model and novel carriers.
基金This work was supported by the National Basic Research Program of China （Nos. 2013CB934103 and 2012CB933003）, the National Natural Science Foundation of China （Nos. 51521001 and 51272197）, the National Science Fund for Distinguished Young Scholars （No. 51425204）, the Hubei Province Natural Science Fund for Distinguished Young Scholars （No. 2014CFA035）, and the Fundamental Research Funds for the Central Universities （Nos. 2015-III-032, 2016-YB-004, and 2015-KF-3）. We thank Prof. D~ Y. Zhao of Fudan University and Prof. J. Liu of Pacific Northwest National Laboratory for useful discussions and assistance with the manuscript.
文摘Metal oxide hollow structures with multilevel interiors are of great interest for potential applications such as catalysis, chemical sensing, drug delivery, and energy storage. However, the controlled synthesis of multilevel nanotubes remains a great challenge. Here we develop a facile interface-modulated approach toward the synthesis of complex metal oxide multilevel nanotubes with tunable interior structures through electrospinning followed by controlled heat treatment. This versatile strategy can be effectively applied to fabricate wire-in-tube and tube- in-tube nanotubes of various metal oxides. These multilevel nanotubes possess a large specific surface area, fast mass transport, good strain accommodation, and high packing density, which are advantageous for lithium-ion batteries （LIBs） and the oxygen reduction reaction （ORR）. Specifically, shrinkable CoMn204 tube-in-tube nanotubes as a lithium-ion battery anode deliver a high discharge capacity of -565 mAh-g-1 at a high rate of 2 A.g-~, maintaining 89% of the latter after 500 cycles. Further, as an oxygen reduction reaction catalyst, these nanotubes also exhibit excellent stability with about 92% current retention after 30,000 s, which is higher than that of commercial Pt/C （81%）. Therefore, this feasible method may push the rapid development of one-dimensional （1D） nanomaterials. These multifunctional nanotubes have great potential in many frontier fields.
基金Supported by the Important National Science & Technology Specific Projects (2009ZX07526-005-05)
文摘A lab-scale integrated treatment system including the novel sequence bio-ecological process （SBEP） and biological aerated filter （BAF） for a sewage mixture （chemistry laboratory wastewater and domestic sewage） was presented in this paper. The main objective of the study was to test the contribution of artificial aeration, recir-culation ratio and mass concentration of steel slag on pollutant removal in winter when the plants are dormant. It had been shown that SBEP and BAF play different roles in removing contaminants from wastewater. During the airflow experiment, the removal efficiency of COD and TP in SBEP was higher than that in BAF, whereas BAF can compensate for the deficiency of SBEP where no significant improvement on ammonium nitrogen removal is ob-served. Yet, the removal etticiencies of COD,TP and NH4^＋ -N in SBEP could be improved apparently when ditterent recireulation ratio or various mass concentration of steel were applied. Especially, when the airflow of 0.06 L·h^-1, the recirculation ratio rate of 80% and the mass concentration of steel of 2.2-2.4 g·L^-1 were applied, thehighest efficiency of 94.6%, 77.9% and 80.7% for COD, TP and NH4^＋ -N were achieved,-respectively,The integrated treatment system of SBEP and BAF was proved to be an effective wastewater treatment technique and a better alternative to treat domestic sewage.
基金the financial support by Higher Education Commission(HEC),Islamabad Pakistan
文摘Highly repeatable multilevel bipolar resistive switching in Ti/Ce Ox/Pt nonvolatile memory device has been demonstrated. X-ray diffraction studies of Ce O2 films reveal the formation of weak polycrystalline structure. The observed good memory performance, including stable cycling endurance and long data retention times（〉10^4s） with an acceptable resistance ratio（～10^2）, enables the device for its applications in future non-volatile resistive random access memories（RRAMs）. Based on the unique distribution characteristics of oxygen vacancies in Ce Ox films, the possible mechanism of multilevel resistive switching in Ce Ox RRAM devices has been discussed. The conduction mechanism in low resistance state is found to be Ohmic due to conductive filamentary paths, while that in the high resistance state was identified as Ohmic for low applied voltages and a space-charge-limited conduction dominated by Schottky emission at high applied voltages.
基金the National Research Foundation of Korea(NRF)grant funded by the Korea government(No.2016R1A3B 1908249)。
文摘Multilevel resistive switching(RS)is a key property to embrace the full potential of memristive devices for non-volatile memory and neuromorphic computing applications.In this study,we employed nanoparticulated cobaltite oxide(Co_(3)O_(4))as a model material to demonstrate the multilevel RS and synaptic learning capabilities because of its multiple and stable redox state properties.The Pt/Co_(3)O_(4)/Pt memristive device exhibited tunable RS properties with respect to different voltages and compliance currents(CC)without the electroforming process.That is,the device showed voltage-dependent RS at a higher CC whereas CC-dependent RS was observed at lower CC.The device showed four different resistance states during endurance and retention measurements and non-volatile memory results indicated that the CC-based measurement had less variation.Besides,we investigated the basic and complex synaptic plasticity properties using the analog current-voltage characteristics of the Pt/Co_(3)O_(4)/Pt device.In particular,we mimicked the potentiation–depression and four-spike time-dependent plasticity(STDP)rules such as asymmetric Hebbian,asymmetric anti-Hebbian,symmetric Hebbian,and symmetric antiHebbian learning rules.The results of the present work indicate that the cobaltite oxide is an excellent nanomaterial for both multilevel RS and neuromorphic computing applications.
文摘During brewery wastewater treatment by a hydrolyzation-food chain reactor(FCR)system,sludge was recycled to the anaerobic segment.With the function of hydrolyzation acidification in the anaerobic segment and the processes of aerobic oxidation and antagonism,preda-tion,interaction and symbiosis among microbes in multi-level oxidation segment,residual sludge could be reduced effectively.The 6-month dynamic experiments show that the average chemical oxygen demand(COD)removal ratio was 92.6% and average sludge production of the aerobic segment was 8.14%,with the COD of the influent at 960–1720 mg/L and hydraulic retention time(HRT)of 12 h.Since the producedsludge could be recycled and hydrolyzed in the anaerobic segment,no excess sludge was produced during the steady running for this system.
基金supported by the National Natural Science Foundation of China(62174059,52250281 and 91963102)the Hong Kong Research Grant Council(15300619)+3 种基金the Science and Technology Projects in Guangzhou(202201000008)Guangdong Science and Technology Project-International Cooperation(2021A0505030064)Guangdong Provincial Key Laboratory of Optical Information Materials and Technology(2017B030301007)the Joint Funds of Basic and Applied Basic Research Foundation of Guangdong Province(2019A1515110605)。
