In order to fully utilize the regenerative braking energy of metro trains and stabilize the metro DC traction busbar voltage,a hybrid regenerative braking energy recovery system with a dual-mode power management strat...In order to fully utilize the regenerative braking energy of metro trains and stabilize the metro DC traction busbar voltage,a hybrid regenerative braking energy recovery system with a dual-mode power management strategy is proposed.Firstly,the construction of the hybrid regenerative braking energy recovery system is explained.Then,based on the power demand of low-voltage load in metro stations,a dual-mode power management strategy is proposed to allocate the reference power of each system according to the different working conditions,and the control methods of each system are set.Finally,the correctness and effectiveness of the dual-mode strategy are verified through simulation,and the proposed braking energy utilization scheme is compared with other singleform utilization schemes.The results illustrate that the hybrid system with the dual-mode strategy can effectively recycle the regenerative braking energy of metro train and inhibit the busbar voltage fluctuation;the proposed braking energy utilization scheme has certain advantages on energy recovery and DC bus voltage stabilization compared with other single-form schemes;the proposed power management strategy can correctly allocate the reference power of each system with a lower construction cost.展开更多
In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To ...In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To address this issue,the application of a virtual synchronous generator(VSG)in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator(AVSG)control strategy for the interface DC/DC converter of the battery in the microgrid.Besides,a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control.Firstly,a theoretical analysis is conducted on the various components of the DC microgrid,the structure of analogous virtual synchronous generator,and the control structure’s main parameters related to the DC microgrid’s inertial behavior.Secondly,the voltage change rate tracking coefficient is introduced to adjust the change of the virtual capacitance and damping coefficient flexibility,which further strengthens the inertia trend of the DC microgrid.Additionally,a small-signal modeling approach is used to analyze the approximate range of the AVSG’s main parameters ensuring system stability.Finally,conduct a simulation analysis by building the model of the DC microgrid system with photovoltaic(PV)and battery energy storage(BES)in MATLAB/Simulink.Simulation results from different scenarios have verified that the AVSG control introduces fixed inertia and damping into the droop control of the battery,resulting in a certain level of inertia enhancement.Furthermore,the additional adaptive control strategy built upon the AVSG control provides better and flexible inertial support for the DC microgrid,further enhances the stability of the DC bus voltage,and has a more positive impact on the battery performance.展开更多
In light of the prevailing issue that the existing convolutional neural network(CNN)power quality disturbance identification method can only extract single-scale features,which leads to a lack of feature information a...In light of the prevailing issue that the existing convolutional neural network(CNN)power quality disturbance identification method can only extract single-scale features,which leads to a lack of feature information and weak anti-noise performance,a new approach for identifying power quality disturbances based on an adaptive Kalman filter(KF)and multi-scale channel attention(MS-CAM)fused convolutional neural network is suggested.Single and composite-disruption signals are generated through simulation.The adaptive maximum likelihood Kalman filter is employed for noise reduction in the initial disturbance signal,and subsequent integration of multi-scale features into the conventional CNN architecture is conducted.The multi-scale features of the signal are captured by convolution kernels of different sizes so that the model can obtain diverse feature expressions.The attention mechanism(ATT)is introduced to adaptively allocate the extracted features,and the features are fused and selected to obtain the new main features.The Softmax classifier is employed for the classification of power quality disturbances.Finally,by comparing the recognition accuracy of the convolutional neural network(CNN),the model using the attention mechanism,the bidirectional long-term and short-term memory network(MS-Bi-LSTM),and the multi-scale convolutional neural network(MSCNN)with the attention mechanism with the proposed method.The simulation results demonstrate that the proposed method is higher than CNN,MS-Bi-LSTM,and MSCNN,and the overall recognition rate exceeds 99%,and the proposed method has significant classification accuracy and robust classification performance.This achievement provides a new perspective for further exploration in the field of power quality disturbance classification.展开更多
In this paper,an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load a...In this paper,an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load and PV power variations in a stand-alone DC microgrid.The strategy includes primary and secondary control.Among them,the primary control suppresses the DC microgrid voltage fluctuation through the I and II section control,and the secondary control aims to correct the P-U curve of the energy storage system and the PV system,thus reducing the steady-state bus voltage excursion.The simulation results demonstrate that the proposed control strategy effectively achieves SOC balancing and enhances the immunity of bus voltage.The proposed strategy improves the voltage fluctuation suppression ability by approximately 39.4%and 43.1%under the PV power and load power fluctuation conditions,respectively.Furthermore,the steady-state deviation of the bus voltage,△U_(dc) is only 0.01–0.1 V,ensuring stable operation of the DC microgrid in fluctuating power environments.展开更多
With the penetration of a large number of photovoltaic power generation units and power electronic converters,the DC microgrid shows low inertia characteristics,which might affect the stable operation of the microgrid...With the penetration of a large number of photovoltaic power generation units and power electronic converters,the DC microgrid shows low inertia characteristics,which might affect the stable operation of the microgrid in extreme cases.In order to enhance the“flexible features”of the interface converter connected to the DC bus,a control strategy of DCmicrogrid with photovoltaic and energy storage based on the virtual DC generator(VDCG)is proposed in this paper.The interface converters of the photovoltaic power generation system and the energy storage system simulates the inertia and damping characteristics of the DC generator to improve the stability of the DC bus voltage.The impedance ratio of DC microgrid was obtained by establishing the small-signal model of photovoltaic power generation system and energy storage system,and the Nyquist curves was applied to analyze the small-signal stability of the system.Finally,the simulation results were verified with MATLAB/Simulink.The results show that the proposed control strategy can slow down the fluctuation of bus voltage under the conditions of photovoltaic power fluctuation and load mutation,thus enhancing the system stability.展开更多
Aiming at the problems of multiple types of power quality composite disturbances,strong feature correlation and high recognition error rate,a method of power quality composite disturbances identification based on mult...Aiming at the problems of multiple types of power quality composite disturbances,strong feature correlation and high recognition error rate,a method of power quality composite disturbances identification based on multiresolution S-transform and decision tree was proposed.Firstly,according to IEEE standard,the signal models of seven single power quality disturbances and 17 combined power quality disturbances are given,and the disturbance waveform samples are generated in batches.Then,in order to improve the recognition accuracy,the adjustment factor is introduced to obtain the controllable time-frequency resolution through multi-resolution S-transform time-frequency domain analysis.On this basis,five disturbance time-frequency domain features are extracted,which quantitatively reflect the characteristics of the analyzed power quality disturbance signal,which is less than the traditional method based on S-transform.Finally,three classifiers such as K-nearest neighbor,support vector machine and decision tree algorithm are used to effectively complete the identification of power quality composite disturbances.Simulation results showthat the classification accuracy of decision tree algorithmis higher than that of K-nearest neighbor and support vector machine.Finally,the proposed method is compared with other commonly used recognition algorithms.Experimental results show that the proposedmethod is effective in terms of detection accuracy,especially for combined PQ interference.展开更多
The electromagnetic separation method is a new approach to treat ship-based marine oily wastewater,in which oil droplets are dispersed in seawater(oil-seawater mixed flow).In order to clarify the separation process an...The electromagnetic separation method is a new approach to treat ship-based marine oily wastewater,in which oil droplets are dispersed in seawater(oil-seawater mixed flow).In order to clarify the separation process and determine the separation characteristics,the flow field and volume fraction of the oil droplets of the oil-seawater mixed flow under an applied electromagnetic field with different operating conditions were investigated by 2D numerical simulations with the Eulerian model.The results show that:(1)the downward Lorentz force causes seawater to flow downwards and the oil droplets to move upwards due to the electromagnetic separation force in the effective section of the separation channel;(2)the volume fraction of the oil droplets at the top of the outlet section increases with the current density,magnetic field,and the diameter of the oil droplet and decreases with the inlet velocity of the oily seawater.The results provide useful guidance for the design of electromagnetic separation devices of the oil-seawater mixed flow.展开更多
Microsensor measurements and fluorescence in situ hybridization (FISH) analysis were combined to investigate the microbial populations and activities in a laboratory-scale sequencing batch reactor (SBR) for comple...Microsensor measurements and fluorescence in situ hybridization (FISH) analysis were combined to investigate the microbial populations and activities in a laboratory-scale sequencing batch reactor (SBR) for completely autotrophic nitrogen removal over nitrite (CANON). Fed with synthetic wastewater rich in ammo- nia, the SBR removed 82.54-5.4% ofinfluent nitrogen and a maximum nitrogen-removal rate of 0.52kgN.m 3.d-l was achieved. The FISH analysis revealed that aerobic ammonium-oxidizing bacteria (AerAOB) Nitrosomonas and anaerobic ammonium-oxidizing bacteria (AnAOB) dominated the community. To quantify the microbial activities inside the sludge aggregates, microprofiles were measured using pH, dissolved oxygen (DO), NH+, NO+ and NO3 microelectrodes. In the outer layer of sludge aggregates (0-700 μm), nitrite-oxidizing bacteria (NOB) showed high activity with 4.1 gmol-cm3+ h-1 of maximum nitrate production rate under the condition of DO concentration higher than 3.3 mg. L 1. Maximum AerAOB activity was detected in the middle layer (depths around 1700 μm) where DO concentration was 1.1 μg. L-1. In the inner layer (2200-3500μm), where DO concentration was below 0.9 mg. L-1, AnAOB activity was detected. We thus showed that information obtained from microscopic views can be helpful in optimizing the SBR performance.展开更多
Amino acids containing the thiol group play significant roles in keeping biological oxidation reduction balance. Due to the important cellular function of biothiols, it is imperative to develop efficient methods to de...Amino acids containing the thiol group play significant roles in keeping biological oxidation reduction balance. Due to the important cellular function of biothiols, it is imperative to develop efficient methods to detect biothiols in complicate biological systems. In this work, we developed a cyanine-based fluorescent probe utilizing thioether as a detecting group, which showed the fluorescent "turn-on" response towards GSH and it can be used as a biomarker to determine the cellular GSH.展开更多
A ratiometric probe(HBT-HBZ)bearing 2-hydrazino benzothiazole and 3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylbenzaldehyde for sensing hypochlorous acid(HClO)with high selectivity and sensitivity is reported in this ar...A ratiometric probe(HBT-HBZ)bearing 2-hydrazino benzothiazole and 3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylbenzaldehyde for sensing hypochlorous acid(HClO)with high selectivity and sensitivity is reported in this article.The fluorescence intensity ratios(I470nm/I572nm)of the probe with different concentrations of analyte showed excellent selectivity and a linear response to minor changes in HClO.The detection limit of 24 nmol/L suggests that the sensor is very sensitive to HClO.According to the series of performed experiments,HBT-HBZ has practical applications,such as the detection of HClO residues in tap water,which has been rarely reported.In addition,confocal laser microscopy experiments confirmed that HBT-HBZ can selectively recognize HClO in HeLa cells.A ratiometric probe(HBT-HBZ)for sensing HClO with high selectivity and sensitivity is reported in this article.The probe exhibited high selectivity for HClO among other ROS,RNS and anions.In addition,HBTHBZ has some practical applications such as the analysis of the HClO content in tap water.Furthermore,confocal fluorescence microscopy imaging showed that HBT-HBZ can be applied for detecting HClO in living cells.展开更多
A new simple bifunctional chemosensor 1 based on rhodamine was synthesized by hydrazide and formylformic acid,which could detect Cu^2+and Hg^2+via dif ferent detecting methods in CH3 CN-HEPES buffer solution(20 mmol/L...A new simple bifunctional chemosensor 1 based on rhodamine was synthesized by hydrazide and formylformic acid,which could detect Cu^2+and Hg^2+via dif ferent detecting methods in CH3 CN-HEPES buffer solution(20 mmol/L,pH 7.4)(1:9,v/v)respectively.When sensor 1 bound with Cu^2+,it showed a colorimetric change,while a selective enhancement in fluorescence occurred upon 1 binding with Hg^2+,resulting from the spirolatam-ring opening process.The binding modes of 1 with Cu^2+and Hg^2+were investigated based on UV,fluorescence change,ESI-Mass and Job’s Plot data.Moreover,sensor 1 could selectively detect target ion in a mixed solution of Cu^2+and Hg^2+,and the two metal ions do not inte rfere with each other in the process of detecting Cu^2+or Hg^2+with 1.展开更多
Hypochlorous acid(HOCl) plays a vital role in many physiological and pathological processes as one of reactive oxygen species(ROS). Developing highly sensitive and selective methods for HOCl detection is of signif...Hypochlorous acid(HOCl) plays a vital role in many physiological and pathological processes as one of reactive oxygen species(ROS). Developing highly sensitive and selective methods for HOCl detection is of significant interest. In this work, we developed a benzothiazole based probe 1 for ratiometric fluorescence detection of hypochlorite in living cells. The probe can detect HOCl with high selectivity, fast response(within 30 s) as well as low detection limit(0.18 mmol/L). Fluorescence co-localization studies demonstrated that probe 1 was a mitochondria-targeted fluorescent probe. Furthermore, confocal fluorescence images of He La cell indicated that probe 1 could be used for monitoring intracellular HOCl in living cells. Finally, test strips experiment suggests that the probe 1 can detect the hypochlorous acid in tap water accompanied by remarkable color change.展开更多
Biosensors that effectively and selectively detect biomolecules and monitor biological processes have become an important component of biological and medical studies. Because they possess several attractive features, ...Biosensors that effectively and selectively detect biomolecules and monitor biological processes have become an important component of biological and medical studies. Because they possess several attractive features, polydiacetylenes(PDAs) have been employed as frameworks for fluorometric and colorimetric sensors. PDAs are formed in their non-fluorescent blue-colored state by UV light induced polymerization of head group functionalized diacetylene monomers(DAs) and they undergo a transition to form fluorescent red-colored PDAs in response to a variety of stimuli. Importantly, by properly choosing a headgroup in the DA, the formed PDA can be designed to undergo a fluorescence/colorimetric change in response to a specific biological stimulus. This review summarizes recent advances that have been made in the development of PDA biosensors with an emphasis being given to design strategies and applications.展开更多
The different oxidation states of sulphur atom play a significant role on functional materials.In this work,a aryl-thioether and its sulphone substituted benzo[c][1,2,5]oxadiazole dyes were synthesized and utilized to...The different oxidation states of sulphur atom play a significant role on functional materials.In this work,a aryl-thioether and its sulphone substituted benzo[c][1,2,5]oxadiazole dyes were synthesized and utilized to determine thiol-containing amino acids.The result of selectivity experiments showed they detected the cysteine and homocysteine under physiological condition with negligible interference from other amino acids.In comparison to the thioether dye,the sulphone-based dye exhibited much faster response time for Cys and Hcy.However,the sulphone restricted its thiol-reactivity and bioimaging performance in living cells.By reducing the oxidation state of sulphur atom,we amazedly found that the sulfoxide-based dye still maintained high selectivity ultrafast response time for Cys/Hcy under physiological condition.It was worth mentioning that it also had high reactivity and good bioimaging performance that sulfone compounds did not have.展开更多
Purpose The machine protection system(MPS)is an essential part of the BRing(Booster Ring)at the HIAF(High Intensity heavy ion Accelerator Facility)to protect the accelerator from possible accidents.The high accumulati...Purpose The machine protection system(MPS)is an essential part of the BRing(Booster Ring)at the HIAF(High Intensity heavy ion Accelerator Facility)to protect the accelerator from possible accidents.The high accumulation intensity and the complex operation mode of the BRing require MPS to respond quickly and operate stably.So,the detailed physical scheme of beam dump is proposed,and the corresponding simulation results are discussed in this paper.Method For this purpose,a multi-phased beam dump scheme based on the bipolar operation of fast extraction kicker magnets is proposed.The basic physical dimensions of the stoppers and energy deposited analysis have been calculated.Results and conclusion The multi-phased beam dump scheme is able to meet the engineering requirements,and the stopping efficiency can reach 100%for bunched beam.展开更多
基金funded by Project supported by the Natural Science Foundation of Gansu Province,China(Grant No.22JR5RA318).
文摘In order to fully utilize the regenerative braking energy of metro trains and stabilize the metro DC traction busbar voltage,a hybrid regenerative braking energy recovery system with a dual-mode power management strategy is proposed.Firstly,the construction of the hybrid regenerative braking energy recovery system is explained.Then,based on the power demand of low-voltage load in metro stations,a dual-mode power management strategy is proposed to allocate the reference power of each system according to the different working conditions,and the control methods of each system are set.Finally,the correctness and effectiveness of the dual-mode strategy are verified through simulation,and the proposed braking energy utilization scheme is compared with other singleform utilization schemes.The results illustrate that the hybrid system with the dual-mode strategy can effectively recycle the regenerative braking energy of metro train and inhibit the busbar voltage fluctuation;the proposed braking energy utilization scheme has certain advantages on energy recovery and DC bus voltage stabilization compared with other single-form schemes;the proposed power management strategy can correctly allocate the reference power of each system with a lower construction cost.
基金funded by the National Natural Science Foundation of China(52067013),and the Provincial Natural Science Foundation of Gansu(20JR5RA395).
文摘In the DC microgrid,the lack of inertia and damping in power electronic converters results in poor stability of DC bus voltage and low inertia of the DC microgrid during fluctuations in load and photovoltaic power.To address this issue,the application of a virtual synchronous generator(VSG)in grid-connected inverters control is referenced and proposes a control strategy called the analogous virtual synchronous generator(AVSG)control strategy for the interface DC/DC converter of the battery in the microgrid.Besides,a flexible parameter adaptive control method is introduced to further enhance the inertial behavior of the AVSG control.Firstly,a theoretical analysis is conducted on the various components of the DC microgrid,the structure of analogous virtual synchronous generator,and the control structure’s main parameters related to the DC microgrid’s inertial behavior.Secondly,the voltage change rate tracking coefficient is introduced to adjust the change of the virtual capacitance and damping coefficient flexibility,which further strengthens the inertia trend of the DC microgrid.Additionally,a small-signal modeling approach is used to analyze the approximate range of the AVSG’s main parameters ensuring system stability.Finally,conduct a simulation analysis by building the model of the DC microgrid system with photovoltaic(PV)and battery energy storage(BES)in MATLAB/Simulink.Simulation results from different scenarios have verified that the AVSG control introduces fixed inertia and damping into the droop control of the battery,resulting in a certain level of inertia enhancement.Furthermore,the additional adaptive control strategy built upon the AVSG control provides better and flexible inertial support for the DC microgrid,further enhances the stability of the DC bus voltage,and has a more positive impact on the battery performance.
基金The project is supported by the National Natural Science Foundation of China(52067013)the Key Projects of the Natural Science Foundation of Gansu Provincial Science and Technology Department(22JR5RA318).
文摘In light of the prevailing issue that the existing convolutional neural network(CNN)power quality disturbance identification method can only extract single-scale features,which leads to a lack of feature information and weak anti-noise performance,a new approach for identifying power quality disturbances based on an adaptive Kalman filter(KF)and multi-scale channel attention(MS-CAM)fused convolutional neural network is suggested.Single and composite-disruption signals are generated through simulation.The adaptive maximum likelihood Kalman filter is employed for noise reduction in the initial disturbance signal,and subsequent integration of multi-scale features into the conventional CNN architecture is conducted.The multi-scale features of the signal are captured by convolution kernels of different sizes so that the model can obtain diverse feature expressions.The attention mechanism(ATT)is introduced to adaptively allocate the extracted features,and the features are fused and selected to obtain the new main features.The Softmax classifier is employed for the classification of power quality disturbances.Finally,by comparing the recognition accuracy of the convolutional neural network(CNN),the model using the attention mechanism,the bidirectional long-term and short-term memory network(MS-Bi-LSTM),and the multi-scale convolutional neural network(MSCNN)with the attention mechanism with the proposed method.The simulation results demonstrate that the proposed method is higher than CNN,MS-Bi-LSTM,and MSCNN,and the overall recognition rate exceeds 99%,and the proposed method has significant classification accuracy and robust classification performance.This achievement provides a new perspective for further exploration in the field of power quality disturbance classification.
基金supported by the NationalNatural Science Foundation of China(No.52067013)the Natural Science Foundation of Gansu Province(No.20JR5RA395)as well as the Tianyou Innovation Team of Lanzhou Jiaotong University(TY202010).
文摘In this paper,an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load and PV power variations in a stand-alone DC microgrid.The strategy includes primary and secondary control.Among them,the primary control suppresses the DC microgrid voltage fluctuation through the I and II section control,and the secondary control aims to correct the P-U curve of the energy storage system and the PV system,thus reducing the steady-state bus voltage excursion.The simulation results demonstrate that the proposed control strategy effectively achieves SOC balancing and enhances the immunity of bus voltage.The proposed strategy improves the voltage fluctuation suppression ability by approximately 39.4%and 43.1%under the PV power and load power fluctuation conditions,respectively.Furthermore,the steady-state deviation of the bus voltage,△U_(dc) is only 0.01–0.1 V,ensuring stable operation of the DC microgrid in fluctuating power environments.
基金funded by the National Natural Science Foundation of China(52067013)the Provincial Natural Science Foundation of Gansu(20JR5RA395).
文摘With the penetration of a large number of photovoltaic power generation units and power electronic converters,the DC microgrid shows low inertia characteristics,which might affect the stable operation of the microgrid in extreme cases.In order to enhance the“flexible features”of the interface converter connected to the DC bus,a control strategy of DCmicrogrid with photovoltaic and energy storage based on the virtual DC generator(VDCG)is proposed in this paper.The interface converters of the photovoltaic power generation system and the energy storage system simulates the inertia and damping characteristics of the DC generator to improve the stability of the DC bus voltage.The impedance ratio of DC microgrid was obtained by establishing the small-signal model of photovoltaic power generation system and energy storage system,and the Nyquist curves was applied to analyze the small-signal stability of the system.Finally,the simulation results were verified with MATLAB/Simulink.The results show that the proposed control strategy can slow down the fluctuation of bus voltage under the conditions of photovoltaic power fluctuation and load mutation,thus enhancing the system stability.
基金Foundation of China(No.52067013)the Key Natural Science Fund Project of Gansu Provincial Department of Science and Technology(No.21JR7RA280)+1 种基金the Tianyou Innovation Team Science Foundation of Intelligent Power Supply and State Perception for Rail Transit(No.TY202010)the Natural Science Foundation of Gansu Province(No.20JR5RA395).
文摘Aiming at the problems of multiple types of power quality composite disturbances,strong feature correlation and high recognition error rate,a method of power quality composite disturbances identification based on multiresolution S-transform and decision tree was proposed.Firstly,according to IEEE standard,the signal models of seven single power quality disturbances and 17 combined power quality disturbances are given,and the disturbance waveform samples are generated in batches.Then,in order to improve the recognition accuracy,the adjustment factor is introduced to obtain the controllable time-frequency resolution through multi-resolution S-transform time-frequency domain analysis.On this basis,five disturbance time-frequency domain features are extracted,which quantitatively reflect the characteristics of the analyzed power quality disturbance signal,which is less than the traditional method based on S-transform.Finally,three classifiers such as K-nearest neighbor,support vector machine and decision tree algorithm are used to effectively complete the identification of power quality composite disturbances.Simulation results showthat the classification accuracy of decision tree algorithmis higher than that of K-nearest neighbor and support vector machine.Finally,the proposed method is compared with other commonly used recognition algorithms.Experimental results show that the proposedmethod is effective in terms of detection accuracy,especially for combined PQ interference.
基金The Tianjin Science and Technology Plan Project under contract No.15YFYSGX00010the Tianjin Bureau of Marine Science and Technology Plan Project under contract No.KJXH2015-05
文摘The electromagnetic separation method is a new approach to treat ship-based marine oily wastewater,in which oil droplets are dispersed in seawater(oil-seawater mixed flow).In order to clarify the separation process and determine the separation characteristics,the flow field and volume fraction of the oil droplets of the oil-seawater mixed flow under an applied electromagnetic field with different operating conditions were investigated by 2D numerical simulations with the Eulerian model.The results show that:(1)the downward Lorentz force causes seawater to flow downwards and the oil droplets to move upwards due to the electromagnetic separation force in the effective section of the separation channel;(2)the volume fraction of the oil droplets at the top of the outlet section increases with the current density,magnetic field,and the diameter of the oil droplet and decreases with the inlet velocity of the oily seawater.The results provide useful guidance for the design of electromagnetic separation devices of the oil-seawater mixed flow.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 51108367), Specialized Research Fund for the Doctoral Program of Higher Education (No. 20116120120009), Natural Science Foundation of Shaanxi Province (No. 2014JQ7243) and innovative research team of Xi'an University of Architecture and Technology.
文摘Microsensor measurements and fluorescence in situ hybridization (FISH) analysis were combined to investigate the microbial populations and activities in a laboratory-scale sequencing batch reactor (SBR) for completely autotrophic nitrogen removal over nitrite (CANON). Fed with synthetic wastewater rich in ammo- nia, the SBR removed 82.54-5.4% ofinfluent nitrogen and a maximum nitrogen-removal rate of 0.52kgN.m 3.d-l was achieved. The FISH analysis revealed that aerobic ammonium-oxidizing bacteria (AerAOB) Nitrosomonas and anaerobic ammonium-oxidizing bacteria (AnAOB) dominated the community. To quantify the microbial activities inside the sludge aggregates, microprofiles were measured using pH, dissolved oxygen (DO), NH+, NO+ and NO3 microelectrodes. In the outer layer of sludge aggregates (0-700 μm), nitrite-oxidizing bacteria (NOB) showed high activity with 4.1 gmol-cm3+ h-1 of maximum nitrate production rate under the condition of DO concentration higher than 3.3 mg. L 1. Maximum AerAOB activity was detected in the middle layer (depths around 1700 μm) where DO concentration was 1.1 μg. L-1. In the inner layer (2200-3500μm), where DO concentration was below 0.9 mg. L-1, AnAOB activity was detected. We thus showed that information obtained from microscopic views can be helpful in optimizing the SBR performance.
文摘Amino acids containing the thiol group play significant roles in keeping biological oxidation reduction balance. Due to the important cellular function of biothiols, it is imperative to develop efficient methods to detect biothiols in complicate biological systems. In this work, we developed a cyanine-based fluorescent probe utilizing thioether as a detecting group, which showed the fluorescent "turn-on" response towards GSH and it can be used as a biomarker to determine the cellular GSH.
基金the National Key Research and Development Program of China(No.2018YFA0902200)the National Natural Science Foundation of China(Nos.21722605,21978131 and 21878156)+1 种基金the Six Talent Peaks Project in Jiangsu Province(No.XCL-034)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘A ratiometric probe(HBT-HBZ)bearing 2-hydrazino benzothiazole and 3-(benzo[d]thiazol-2-yl)-2-hydroxy-5-methylbenzaldehyde for sensing hypochlorous acid(HClO)with high selectivity and sensitivity is reported in this article.The fluorescence intensity ratios(I470nm/I572nm)of the probe with different concentrations of analyte showed excellent selectivity and a linear response to minor changes in HClO.The detection limit of 24 nmol/L suggests that the sensor is very sensitive to HClO.According to the series of performed experiments,HBT-HBZ has practical applications,such as the detection of HClO residues in tap water,which has been rarely reported.In addition,confocal laser microscopy experiments confirmed that HBT-HBZ can selectively recognize HClO in HeLa cells.A ratiometric probe(HBT-HBZ)for sensing HClO with high selectivity and sensitivity is reported in this article.The probe exhibited high selectivity for HClO among other ROS,RNS and anions.In addition,HBTHBZ has some practical applications such as the analysis of the HClO content in tap water.Furthermore,confocal fluorescence microscopy imaging showed that HBT-HBZ can be applied for detecting HClO in living cells.
基金supported by the National Key Research and Development Program of China(No.2018YFA0902200)the National Natural Science Foundation of China(Nos.21978131,21722605 and 21878156)+1 种基金the Six Talent Peaks Project in Jiangsu Province(No.XCL-034)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘A new simple bifunctional chemosensor 1 based on rhodamine was synthesized by hydrazide and formylformic acid,which could detect Cu^2+and Hg^2+via dif ferent detecting methods in CH3 CN-HEPES buffer solution(20 mmol/L,pH 7.4)(1:9,v/v)respectively.When sensor 1 bound with Cu^2+,it showed a colorimetric change,while a selective enhancement in fluorescence occurred upon 1 binding with Hg^2+,resulting from the spirolatam-ring opening process.The binding modes of 1 with Cu^2+and Hg^2+were investigated based on UV,fluorescence change,ESI-Mass and Job’s Plot data.Moreover,sensor 1 could selectively detect target ion in a mixed solution of Cu^2+and Hg^2+,and the two metal ions do not inte rfere with each other in the process of detecting Cu^2+or Hg^2+with 1.
基金supported by the National Natural Science Foundation of China(Nos.21376117,21406109 and 31401588)the Jiangsu Natural Science Funds for Distinguished Young Scholars(No.BK20140043)+1 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.14KJA150005)the Qing Lan Project and the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘Hypochlorous acid(HOCl) plays a vital role in many physiological and pathological processes as one of reactive oxygen species(ROS). Developing highly sensitive and selective methods for HOCl detection is of significant interest. In this work, we developed a benzothiazole based probe 1 for ratiometric fluorescence detection of hypochlorite in living cells. The probe can detect HOCl with high selectivity, fast response(within 30 s) as well as low detection limit(0.18 mmol/L). Fluorescence co-localization studies demonstrated that probe 1 was a mitochondria-targeted fluorescent probe. Furthermore, confocal fluorescence images of He La cell indicated that probe 1 could be used for monitoring intracellular HOCl in living cells. Finally, test strips experiment suggests that the probe 1 can detect the hypochlorous acid in tap water accompanied by remarkable color change.
基金financially supported by the National Key Research and Development Program of China (No. 2018YFA0902200)the National Natural Science Foundation of China (Nos.21722605,21978131 and 21878156)+1 种基金the Six Talent Peaks Project in Jiangsu Province (No.XCL-034)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Biosensors that effectively and selectively detect biomolecules and monitor biological processes have become an important component of biological and medical studies. Because they possess several attractive features, polydiacetylenes(PDAs) have been employed as frameworks for fluorometric and colorimetric sensors. PDAs are formed in their non-fluorescent blue-colored state by UV light induced polymerization of head group functionalized diacetylene monomers(DAs) and they undergo a transition to form fluorescent red-colored PDAs in response to a variety of stimuli. Importantly, by properly choosing a headgroup in the DA, the formed PDA can be designed to undergo a fluorescence/colorimetric change in response to a specific biological stimulus. This review summarizes recent advances that have been made in the development of PDA biosensors with an emphasis being given to design strategies and applications.
基金the National Natural Science Foundation of China(Nos.21676113,21402057,21772054,21472059)Distinguished Young Scholar of Hubei Province(No.2018CFA079)+5 种基金Youth Chen-Guang Project of Wuhan(No.2016070204010098)the 111 Project B17019the Ministry-Province Jointly Constructed Base for State Key Lab-Shenzhen Key Laboratory of Chemical Biology(Shenzhen),the State Key Laboratory of Materials-Oriented Chemical Engineering(No.KL17-10)Open Project Fund of Key Laboratory of Natural Resources of Changbai Mountain&Functional Molecules(Yanbian University),Ministry of Education(No.NRFM201701)the Foundation of Key Laboratory of Synthetic and Biological Colloids,Ministry of Education,Jiangnan University(No.JDSJ2017-07)the Self-determined Research Funds of CCNU from the Colleges’Basic Research and Operation of MOE(No.CCNU18TS012)。
文摘The different oxidation states of sulphur atom play a significant role on functional materials.In this work,a aryl-thioether and its sulphone substituted benzo[c][1,2,5]oxadiazole dyes were synthesized and utilized to determine thiol-containing amino acids.The result of selectivity experiments showed they detected the cysteine and homocysteine under physiological condition with negligible interference from other amino acids.In comparison to the thioether dye,the sulphone-based dye exhibited much faster response time for Cys and Hcy.However,the sulphone restricted its thiol-reactivity and bioimaging performance in living cells.By reducing the oxidation state of sulphur atom,we amazedly found that the sulfoxide-based dye still maintained high selectivity ultrafast response time for Cys/Hcy under physiological condition.It was worth mentioning that it also had high reactivity and good bioimaging performance that sulfone compounds did not have.
基金Thanks for the support from the National Key R&D Program of China(Grant NO.2019YFA0405400)National Natural Science Foundation of China(Grant No.11905268)the support from Guangdong Innovative and Entrepreneurial Research Team Program(Grant No.2016ZT06G373).
文摘Purpose The machine protection system(MPS)is an essential part of the BRing(Booster Ring)at the HIAF(High Intensity heavy ion Accelerator Facility)to protect the accelerator from possible accidents.The high accumulation intensity and the complex operation mode of the BRing require MPS to respond quickly and operate stably.So,the detailed physical scheme of beam dump is proposed,and the corresponding simulation results are discussed in this paper.Method For this purpose,a multi-phased beam dump scheme based on the bipolar operation of fast extraction kicker magnets is proposed.The basic physical dimensions of the stoppers and energy deposited analysis have been calculated.Results and conclusion The multi-phased beam dump scheme is able to meet the engineering requirements,and the stopping efficiency can reach 100%for bunched beam.