In this paper,we mainly focus on a type of nonlinear Choquard equations with nonconstant potential.Under appropriate hypotheses on potential function and nonlinear terms,we prove that the above Choquard equation with ...In this paper,we mainly focus on a type of nonlinear Choquard equations with nonconstant potential.Under appropriate hypotheses on potential function and nonlinear terms,we prove that the above Choquard equation with prescribed 2-norm has some normalized solutions by introducing variational methods.展开更多
The ReaxFF can describe the properties of energetic materials(EMs)at equilibrium state,but does not work properly in simulating high-energy particle irradiation process because of its weak short-range interaction.In t...The ReaxFF can describe the properties of energetic materials(EMs)at equilibrium state,but does not work properly in simulating high-energy particle irradiation process because of its weak short-range interaction.In this paper,a modification was made for such a potential by connecting ZieglerBiersack-Littmark(ZBL)potential to ReaxFF-lg through comparing to Density Functional Theory(DFT)results to accurately describe short-range interactions.After modification,the newly fitted ReaxFF-lg/ZBL potential predicts better the equation of state for EMs In displacement cascade simulations,comparing to results from ab initio molecular dynamics(AIMD),ReaxFF-lg/ZBL presented the similar transferred energy from a primary knock-on atom to surrounding atoms,better than the original ReaxFF-lg potential.Further large-scale displacement cascade simulations indicated ReaxFF-lg/ZBL could be applied for cascade simulations with PKA energy from less than 1 keV to high energy(e.g.35 keV)cases,which is suitable for effectively simulating high-energy displacement cascades in EMs using molecular dynamics method.展开更多
Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,t...Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.展开更多
Small video satellites have unique advantages of short development cycle,agile attitude maneuver,real-time video imaging.They have broad application prospects in space debris,faulty spacecraft,and other space target d...Small video satellites have unique advantages of short development cycle,agile attitude maneuver,real-time video imaging.They have broad application prospects in space debris,faulty spacecraft,and other space target detection and tracking.However,when a space target first enters the camera’s visual field,it has a relatively large angular velocity relative to the satellite,which makes it easy to deviate from the visual field and cause off-target problems.This paper proposes a novel visual tracking control method based on potential function preventing missed targets in space.Firstly,a circular area in the image plane is designed as a mandatory restricted projection area of the target and a visual tracking controller based on image error.Then,a potential function is designed to ensure continuous and stable tracking of the target after entering the visual field.Finally,the stability of the control is proved using Barbarat’s lemma.By setting the same conditions and comparing with the simulation results of the proportion-derivative(PD)control method,the results show that when there is a large relative attitude motion angular velocity between the target and the satellite,the track-ing method based on potential function can ensure that the tar-get does not deviate from the field-of-view during the tracking control process,and the projection of target is controlled to the desired position.The proposed control method is effective in eliminating tracking error and preventing off-target simultane-ously.展开更多
Based on the characters of plant potentials, it introduced the construction and technology in developing the measuring system of plant electrical potentials, the input impedance of the amplifier must be enough high(= ...Based on the characters of plant potentials, it introduced the construction and technology in developing the measuring system of plant electrical potentials, the input impedance of the amplifier must be enough high(= 1010～ 1012Ω) in order to measuring the plant weak signals and ensuring high common mode rejection ratio (CMRR). And wavelet transform was applied in denoising based on cross-validation (CV)threshold value. the experiment showed that this system could effectively detect the change of plant potentials,four-week old cucumber was stimulated by heat wounding, the variation potential (VP) and action potential(AP) would be evoked, the AP's varying amplitude can reach 40mV; the AP changed very fast, its duration time is about 0.01～0.02s and its amplitude often change from 15μV～5mV.展开更多
Parkinson disease(PD) is a chronic neurodegenerative disorder caused by progressive dopaminergic neuronal death in the substantia nigra pars compacta within the midbrain.There still is no cure,effective treatments for...Parkinson disease(PD) is a chronic neurodegenerative disorder caused by progressive dopaminergic neuronal death in the substantia nigra pars compacta within the midbrain.There still is no cure,effective treatments for PD,available therapies are only capable of offering temporary and symptomatic relief to the patients.There are certain patents that claim phosphodiesterase(PDE) inhibitors as possible anti-PD drugs,PDE4 is a promising target for the treatment of PD and the underlying mechanism has not yet been well elucidated.PDE4 is an enzyme that specifically hydrolyzes intracellular cyclic adenosine monophosphate(cAMP)throughout the body,including the brain.Most of the available PDE4 inhibitors exert unpleasant and serious side effects,such as emesis and nausea,which hinder its clinical application.Therefore,more efforts are needed before PDE4 inhibitors with high therapeutic indices are available for treatment of PD.FCPR16 is a novel PDE4 inhibitor with little emetic potential,which exhibits excellent enzyme inhibition activity(IC50=90 nmol·L^(-1)).METHODS SH-SY5 Y cell was induced with 1-methyl-4-phenylpyridinium(MPP+)to mimic PD cell injury in vitro,and CCK-8 assay was used to investigate the viability effects of different concentration of FCPR16(3.1-50 μmol·L^(-1)) on MPP+-injured SH-SY5 Y cells.Detection of apoptosis was performed by flow cytometry.The level of ntracellular reactive oxygen species was detected with the fluorescent probe DCFH-DA,and the mitochondrial membrane potential of cells in different experimental groups was detected with the JC-1 fluorescent probe.AO staining and Lysotracker Red staining were used to detect the intracellular antophagy changes.The expression of apoptosis related proteins,autophagy and other related signal molecules were demonstrated by Western blotting.Different cellular signaling pathway inhibitors were used to invesitigate the specific cellular mechanisms of FCPR16 protecting MPP+-induced cell injury.RESULTS FCPR16(12.5-50 μmol·L^(-1)) dose-dependently reduced MPP+-induced decline of cell viability,accompanied by reductions in nuclear condensation and lactate dehydrogenase release.The level of cleaved caspase 3 and the ratio of Bax/Bcl-2 were also decreased after treatment with FCPR16 in MPP+-treated cells.Furthermore,FCPR16(25 μmol·L^(-1)) significantly suppressed the accumulation of reactive oxygen species(ROS),prevented the decline of mitochondrial membrane potential(Δψm) and attenuated the expression of malonaldehyde level.Further studies disclosed that FCPR16 enhanced the levels of cA MP and the exchange protein directly activated by cA MP(Epac) in SHSY5 Y cel s.Western blotting analysis revealed that FCPR16 increased the phosphorylation of c AMP response element-binding protein(CREB) and protein kinase B(Akt)down-regulated by MPP+in SHSY5 Y cells.Moreover,the inhibitory effects of FCPR16 on the production of ROS and Δψm loss could be blocked by PKA inhibitor H-89 and Akt inhibitor KRX-0401.CONCLUSION The novel PDE4 inhibitor FCPR16 can protect against damaging pathways including oxidative stress,mitochondrial dysfunction and apoptosis in SH-SY5 Y cells.FCPR16 preventes MPP+-induced neurotoxicity through activation of cAMP/PKA/CREB and Epac/Akt signaling pathways.These may lead to develop mechanism based therapeutics and improved pharmacotherapy for PD.It is reasonable to assume that FCPR16 is a potential candidate for the prevention and treatment of PD.展开更多
The target's threat prediction is an essential procedure for the situation analysis in an aerial defense system.However,the traditional threat prediction methods mostly ignore the effect of commander's emotion...The target's threat prediction is an essential procedure for the situation analysis in an aerial defense system.However,the traditional threat prediction methods mostly ignore the effect of commander's emotion.They only predict a target's present threat from the target's features itself,which leads to their poor ability in a complex situation.To aerial targets,this paper proposes a method for its potential threat prediction considering commander emotion(PTP-CE)that uses the Bi-directional LSTM(BiLSTM)network and the backpropagation neural network(BP)optimized by the sparrow search algorithm(SSA).Furthermore,we use the BiLSTM to predict the target's future state from real-time series data,and then adopt the SSA-BP to combine the target's state with the commander's emotion to establish a threat prediction model.Therefore,the target's potential threat level can be obtained by this threat prediction model from the predicted future state and the recognized emotion.The experimental results show that the PTP-CE is efficient for aerial target's state prediction and threat prediction,regardless of commander's emotional effect.展开更多
Cooperative path planning is an important area in fixed-wing UAV swarm.However,avoiding multiple timevarying obstacles and avoiding local optimum are two challenges for existing approaches in a dynamic environment.Fir...Cooperative path planning is an important area in fixed-wing UAV swarm.However,avoiding multiple timevarying obstacles and avoiding local optimum are two challenges for existing approaches in a dynamic environment.Firstly,a normalized artificial potential field optimization is proposed by reconstructing a novel function with anisotropy in each dimension,which can make the flight speed of a fixed UAV swarm independent of the repulsive/attractive gain coefficient and avoid trapping into local optimization and local oscillation.Then,taking into account minimum velocity and turning angular velocity of fixed-wing UAV swarm,a strategy of decomposing target vector to avoid moving obstacles and pop-up threats is proposed.Finally,several simulations are carried out to illustrate superiority and effectiveness.展开更多
Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition di...Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached.In this work,a ductile coating of Ni was introduced to a tungsten-zirconium(W-Zr)alloy,a typical brittle RSM,to preserve the damage potential of the projectile.Detonation driving tests were carried out with X-ray photography and gunpowder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples,respectively.The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction.The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions,whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving.The crack propagation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile.Specifically,the Ni coating envelops theW-Zr core until the coated sphere penetrates the target,and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.展开更多
A new anodic material of ternary Pb-0.8%Ag-(0-5.0%)Bi alloy for zinc electrowinning was obtained by doping Bi.The anodic oxygen evolution potential,corrosion rate,surface products after polarization,and microstructure...A new anodic material of ternary Pb-0.8%Ag-(0-5.0%)Bi alloy for zinc electrowinning was obtained by doping Bi.The anodic oxygen evolution potential,corrosion rate,surface products after polarization,and microstructures before and after polarization were studied and compared with those of Pb-0.8%Ag anode used in industry.The results show the anodic overpotential decreases with the increase of Bi content in the alloys.When the content of Bi is 1.0%(mass fraction),the anodic overpotential is 40-50 mV lower than that of Pb-0.8%Ag anode.While the corrosion rate decreases and then increases with the increase of Bi content.The Pb-0.8%Ag-0.1%Bi anode has the lowest corrosion rate(0.090 6 mg/(h·cm2).Doping Bi influences the structure of the anodic layer,but does not change the phase.The Pb-0.8%Ag-1.0%Bi anode layer is of a more fine-grained structure compared with Pb-0.8%Ag anode.展开更多
Faults and fractures of multiple scales are frequently induced and generated in compressional structural system. Comprehensive identification of these potential faults and fractures that cannot be distinguished direct...Faults and fractures of multiple scales are frequently induced and generated in compressional structural system. Comprehensive identification of these potential faults and fractures that cannot be distinguished directly from seismic profile of the complex structures is still an unanswered problem. Based on the compressional structural geometry and kinematics theories as well as the structural interpretation from seismic data, a set of techniques is established for the identification of potential faults and fractures in compressional structures. Firstly, three-dimensional(3D) patterns and characteristics of the faults directly interpreted from seismic profile were illustrated by 3D structural model. Then, the unfolding index maps, the principal structural curvature maps, and tectonic stress field maps were obtained from structural restoration. Moreover, potential faults and fractures in compressional structures were quantitatively identified relying on comprehensive analysis of these three maps. Successful identification of the potential faults and fractures in Mishrif limestone formation and in Asmari dolomite formation of Buzurgan anticline in Iraq demonstrates the applicability and reliability of these techniques.展开更多
The distributed cooperative decision problems of missiles autonomous formation with network packet loss are investigated by using the potential game based on formation principles.In particular,a dynamic target allocat...The distributed cooperative decision problems of missiles autonomous formation with network packet loss are investigated by using the potential game based on formation principles.In particular,a dynamic target allocation method for missiles formation is provided based on the potential game and formation principles,after the introduction of cooperative guidance and control system of the missiles formation.Then we seek the optimization of a global utility function through autonomous missiles that are capable of making individually rational decisions to optimize their own utility functions.The first important aspect of the problem is to design an individual utility function considering the characteristics of the missiles formation,with which the objective of the missiles are localized to each missile yet aligned with the global utility function.The second is to equip the missiles with an appropriate coordination mechanism with each missile pursuing the optimization of its own utility function.We present the design procedure for the utility,and present a coordination mechanism based on spatial adaptive play and then introduce the idea of“cyclical selected spatial adaptive play”and“negotiation based on time division multiple address(TDMA)protocol formation support network”.Finally,we present simulations for the distributed dynamic target allocation on the comprehensive digital simulation system,and the results illustrate the effectiveness and engineering applicability of the method.展开更多
The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, tr...The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, trans-membrane pressure and pretreatment time on the permeate concentration and permeate flux were studied. The results show that the necessary pretreatment time (NPT) increases with PAAS concentration, decreases with TMP. The change trend of permeate flux with time is affected by pH. The permeate fluxes rapidly decrease from the start, and then increase gradually to stable values at pH 5.0, pH 7.0 and pH 9.3. However, it decreases gradually with time till a state value at pH 3.0 (iso-electric point, IEP). The removal of small molecules is easy at pH greater than iso-electric point (IEP). The change of filtration potential with time indicates the similar trend to that of permeation concentration, but the former is more convenient for indication of NPT.展开更多
The electrochemical oxidation of galena in collectorless and collector flotation systems, particularly in strong alkaline media, was studied. The results show that, with pH value higher than 12.5 and potentials below ...The electrochemical oxidation of galena in collectorless and collector flotation systems, particularly in strong alkaline media, was studied. The results show that, with pH value higher than 12.5 and potentials below 0.17 V, the oxidation products of galena are elemental sulfur and HPbO - 2. Elemental sulfur was present on the mineral surface in excess of oxidized lead species due to dissolution of HPbO - 2, which is beneficial to the flotation of galena. Under the same conditions, sphalerite and pyrite were depressed as a result of significant surface oxidation. Diethyldithiocarbamate (DDTC) was found to be the most suitable collector for galena flotation in strongly alkaline media. The very potential produced hydrophobic PbD 2-the surface reaction product of DDTC with galena, is 0 to 0.2 V. Meantime DDTC can depress the surface over oxidation of galena. Investigations also indicate that, in the range of -0.9 V to 0.6 V, hydrophobic PbD 2 can be firmly adsorbed on galena.展开更多
A potential energy framework for assessment of grid vulnerability was presented.In the framework,the branch potential energy function model was constructed.Two indexes,current vulnerability and forecasting vulnerabili...A potential energy framework for assessment of grid vulnerability was presented.In the framework,the branch potential energy function model was constructed.Two indexes,current vulnerability and forecasting vulnerability,were calculated.The current vulnerability was used to identify the current vulnerable area through calculating the distance between the current transmitted power and initial transmitted power;and the forecast vulnerability under variation of power injection was used to predict the vulnerable area of next step and verify the current vulnerable area.Numerical simulation was performed under variant operating conditions with IEEE-30 bus system,which shows that almost area of 90% overlaps between current vulnerable area and forecasting vulnerable area,the overlapped area is termed as inherent vulnerable area of grid.When considering N-1 contingency,the assessment results of this method proposed agree with those of optimal power flow.When considering N-2 contingency,optimal power flow fails to obtain correct results,while the method based on energy framework gives reliable results.展开更多
This study develops new real-time freeway rear-end crash potential predictors using support vector machine(SVM) technique. The relationship between rear-end crash occurrences and traffic conditions were explored using...This study develops new real-time freeway rear-end crash potential predictors using support vector machine(SVM) technique. The relationship between rear-end crash occurrences and traffic conditions were explored using historical loop detector data from Interstate-894 in Milwaukee, Wisconsin, USA. The extracted loop detection data were aggregated over different stations and time intervals to produce explanatory features. A feature selection process, which addresses the interaction between SVM classifiers and explanatory features, was adopted to identify the features that significantly influence rear-end crashes. Afterwards, the identified significant explanatory features over three separate time levels were used to train three SVM models. In the end, the multi-layer perceptron(MLP) artificial neural network models were used as benchmarks to evaluate the performance of SVM models. The results show that the proposed feature selection procedure greatly enhances the accuracy and generalization capability of SVM models. Moreover, the optimal SVM classifier achieves 81.1% overall prediction precision rate. In comparison with MLP artificial neural networks, SVM models provide better results in terms of crash prediction accuracy and false positive rate, which confirms the superior performance of SVM technique in rear-end crash potential prediction analysis.展开更多
The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided （into） three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and su...The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided （into） three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and sulfide mineral-sulfide mineral-collector system. In this paper, taking lead, zinc, iron sulfide mineral systems for examples, several models of galvanic coupling were proposed and the effects of galvanic coupling on flotation were discussed. A galvanic contact between galena （or sphalerite） and pyrite contributes to decreasing the content of zinc in lead concentrate, and enhances remarkably the absorption of collector on the galena surface. During grinding, due to galvanic interactions between minerals and steel medium, Fe（OH）3 formed covers on the cathodic mineral surface, affecting its floatability.展开更多
A novel method was designed to solve reinforcement learning problems with artificial potential field.Firstly a reinforcement learning problem was transferred to a path planning problem by using artificial potential fi...A novel method was designed to solve reinforcement learning problems with artificial potential field.Firstly a reinforcement learning problem was transferred to a path planning problem by using artificial potential field(APF),which was a very appropriate method to model a reinforcement learning problem.Secondly,a new APF algorithm was proposed to overcome the local minimum problem in the potential field methods with a virtual water-flow concept.The performance of this new method was tested by a gridworld problem named as key and door maze.The experimental results show that within 45 trials,good and deterministic policies are found in almost all simulations.In comparison with WIERING's HQ-learning system which needs 20 000 trials for stable solution,the proposed new method can obtain optimal and stable policy far more quickly than HQ-learning.Therefore,the new method is simple and effective to give an optimal solution to the reinforcement learning problem.展开更多
The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial ...The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial Markov chain(SMC) that can move in the whole space. Generally, the theoretical backbone of MCRF is conditional independence assumption, which is a way around the problem of knowing joint probabilities of multi-points. This so-called Naive Bayes assumption should not be taken lightly and should be checked whenever possible because it is mathematically difficult to prove. Rather than trap in this independence proving, an appropriate potential function in MRF theory is chosen instead. The MCRF formulas are well deduced and the joint probability of MRF is presented by localization approach, so that the complicated parameter estimation algorithm and iteration process can be avoided. The MCRF model is then applied to the lithofacies identification of a region and compared with triplex Markov chain(TMC) simulation. Analyses show that the MCRF model will not cause underestimation problem and can better reflect the geological sedimentation process.展开更多
Chalcopyrite is one of the most important copper minerals;however,the extracted efficiency of chalcopyrite is still not satisfactory in hydrometallurgy owing to its high lattice energy which leads to its low dissoluti...Chalcopyrite is one of the most important copper minerals;however,the extracted efficiency of chalcopyrite is still not satisfactory in hydrometallurgy owing to its high lattice energy which leads to its low dissolution kinetics.To overcome the difficulties,many advanced technologies have been developed,including the selection of high effectively bacteria,the inhibition of the passivation film adhered onto the minerals surface,and the maintenance of solution redox potential under an optimum range.Up to date,considerable researches on the first two terms have been summarized,while the overview of the last term has been rarely reported.Based on corresponding works in recent years,key trends and roles of solution redox potential in copper hydrometallurgy,including its definition,effect and maintenance,have been introduced in this review.展开更多
基金Supported by the National Natural Science Foundation of China(11671403,11671236,12101192)Henan Provincial General Natural Science Foundation Project(232300420113)。
文摘In this paper,we mainly focus on a type of nonlinear Choquard equations with nonconstant potential.Under appropriate hypotheses on potential function and nonlinear terms,we prove that the above Choquard equation with prescribed 2-norm has some normalized solutions by introducing variational methods.
基金the Natural Science Basic Research Program of Shaanxi(Grant No.2024JC-ZDXM-01)supported by the Youth Innovation Team of Shaanxi Universities(Title:Service Performance Evaluation of Energetic Materials)。
文摘The ReaxFF can describe the properties of energetic materials(EMs)at equilibrium state,but does not work properly in simulating high-energy particle irradiation process because of its weak short-range interaction.In this paper,a modification was made for such a potential by connecting ZieglerBiersack-Littmark(ZBL)potential to ReaxFF-lg through comparing to Density Functional Theory(DFT)results to accurately describe short-range interactions.After modification,the newly fitted ReaxFF-lg/ZBL potential predicts better the equation of state for EMs In displacement cascade simulations,comparing to results from ab initio molecular dynamics(AIMD),ReaxFF-lg/ZBL presented the similar transferred energy from a primary knock-on atom to surrounding atoms,better than the original ReaxFF-lg potential.Further large-scale displacement cascade simulations indicated ReaxFF-lg/ZBL could be applied for cascade simulations with PKA energy from less than 1 keV to high energy(e.g.35 keV)cases,which is suitable for effectively simulating high-energy displacement cascades in EMs using molecular dynamics method.
基金Zhenjiang City Key R&D Plan Modern Agriculture Project(No.SH2021017)Zhenjiang“Jinshan Talents”Project 2021Jiangsu Province“Six Talent Peak”Program(No.XCL-111)。
文摘Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.
文摘Small video satellites have unique advantages of short development cycle,agile attitude maneuver,real-time video imaging.They have broad application prospects in space debris,faulty spacecraft,and other space target detection and tracking.However,when a space target first enters the camera’s visual field,it has a relatively large angular velocity relative to the satellite,which makes it easy to deviate from the visual field and cause off-target problems.This paper proposes a novel visual tracking control method based on potential function preventing missed targets in space.Firstly,a circular area in the image plane is designed as a mandatory restricted projection area of the target and a visual tracking controller based on image error.Then,a potential function is designed to ensure continuous and stable tracking of the target after entering the visual field.Finally,the stability of the control is proved using Barbarat’s lemma.By setting the same conditions and comparing with the simulation results of the proportion-derivative(PD)control method,the results show that when there is a large relative attitude motion angular velocity between the target and the satellite,the track-ing method based on potential function can ensure that the tar-get does not deviate from the field-of-view during the tracking control process,and the projection of target is controlled to the desired position.The proposed control method is effective in eliminating tracking error and preventing off-target simultane-ously.
文摘Based on the characters of plant potentials, it introduced the construction and technology in developing the measuring system of plant electrical potentials, the input impedance of the amplifier must be enough high(= 1010～ 1012Ω) in order to measuring the plant weak signals and ensuring high common mode rejection ratio (CMRR). And wavelet transform was applied in denoising based on cross-validation (CV)threshold value. the experiment showed that this system could effectively detect the change of plant potentials,four-week old cucumber was stimulated by heat wounding, the variation potential (VP) and action potential(AP) would be evoked, the AP's varying amplitude can reach 40mV; the AP changed very fast, its duration time is about 0.01～0.02s and its amplitude often change from 15μV～5mV.
基金NationalNatural Science Foundation of China (81773698)Funding from Guangzhou Science and Technology Department (2015B020211007,201604020112).
文摘Parkinson disease(PD) is a chronic neurodegenerative disorder caused by progressive dopaminergic neuronal death in the substantia nigra pars compacta within the midbrain.There still is no cure,effective treatments for PD,available therapies are only capable of offering temporary and symptomatic relief to the patients.There are certain patents that claim phosphodiesterase(PDE) inhibitors as possible anti-PD drugs,PDE4 is a promising target for the treatment of PD and the underlying mechanism has not yet been well elucidated.PDE4 is an enzyme that specifically hydrolyzes intracellular cyclic adenosine monophosphate(cAMP)throughout the body,including the brain.Most of the available PDE4 inhibitors exert unpleasant and serious side effects,such as emesis and nausea,which hinder its clinical application.Therefore,more efforts are needed before PDE4 inhibitors with high therapeutic indices are available for treatment of PD.FCPR16 is a novel PDE4 inhibitor with little emetic potential,which exhibits excellent enzyme inhibition activity(IC50=90 nmol·L^(-1)).METHODS SH-SY5 Y cell was induced with 1-methyl-4-phenylpyridinium(MPP+)to mimic PD cell injury in vitro,and CCK-8 assay was used to investigate the viability effects of different concentration of FCPR16(3.1-50 μmol·L^(-1)) on MPP+-injured SH-SY5 Y cells.Detection of apoptosis was performed by flow cytometry.The level of ntracellular reactive oxygen species was detected with the fluorescent probe DCFH-DA,and the mitochondrial membrane potential of cells in different experimental groups was detected with the JC-1 fluorescent probe.AO staining and Lysotracker Red staining were used to detect the intracellular antophagy changes.The expression of apoptosis related proteins,autophagy and other related signal molecules were demonstrated by Western blotting.Different cellular signaling pathway inhibitors were used to invesitigate the specific cellular mechanisms of FCPR16 protecting MPP+-induced cell injury.RESULTS FCPR16(12.5-50 μmol·L^(-1)) dose-dependently reduced MPP+-induced decline of cell viability,accompanied by reductions in nuclear condensation and lactate dehydrogenase release.The level of cleaved caspase 3 and the ratio of Bax/Bcl-2 were also decreased after treatment with FCPR16 in MPP+-treated cells.Furthermore,FCPR16(25 μmol·L^(-1)) significantly suppressed the accumulation of reactive oxygen species(ROS),prevented the decline of mitochondrial membrane potential(Δψm) and attenuated the expression of malonaldehyde level.Further studies disclosed that FCPR16 enhanced the levels of cA MP and the exchange protein directly activated by cA MP(Epac) in SHSY5 Y cel s.Western blotting analysis revealed that FCPR16 increased the phosphorylation of c AMP response element-binding protein(CREB) and protein kinase B(Akt)down-regulated by MPP+in SHSY5 Y cells.Moreover,the inhibitory effects of FCPR16 on the production of ROS and Δψm loss could be blocked by PKA inhibitor H-89 and Akt inhibitor KRX-0401.CONCLUSION The novel PDE4 inhibitor FCPR16 can protect against damaging pathways including oxidative stress,mitochondrial dysfunction and apoptosis in SH-SY5 Y cells.FCPR16 preventes MPP+-induced neurotoxicity through activation of cAMP/PKA/CREB and Epac/Akt signaling pathways.These may lead to develop mechanism based therapeutics and improved pharmacotherapy for PD.It is reasonable to assume that FCPR16 is a potential candidate for the prevention and treatment of PD.
基金the National Natural Science Foundation of China(No.61873196 and No.61501336)the Natural Science Foundation of Hubei Province(2019CFB778)+1 种基金the National Defense Pre-research Foundation of Wuhan University of Science and Technology(GF202007)the Postgraduate Innovation and Entrepreneurship Foundation of Wuhan University of Science and Technology(JCX2020095).
文摘The target's threat prediction is an essential procedure for the situation analysis in an aerial defense system.However,the traditional threat prediction methods mostly ignore the effect of commander's emotion.They only predict a target's present threat from the target's features itself,which leads to their poor ability in a complex situation.To aerial targets,this paper proposes a method for its potential threat prediction considering commander emotion(PTP-CE)that uses the Bi-directional LSTM(BiLSTM)network and the backpropagation neural network(BP)optimized by the sparrow search algorithm(SSA).Furthermore,we use the BiLSTM to predict the target's future state from real-time series data,and then adopt the SSA-BP to combine the target's state with the commander's emotion to establish a threat prediction model.Therefore,the target's potential threat level can be obtained by this threat prediction model from the predicted future state and the recognized emotion.The experimental results show that the PTP-CE is efficient for aerial target's state prediction and threat prediction,regardless of commander's emotional effect.
文摘Cooperative path planning is an important area in fixed-wing UAV swarm.However,avoiding multiple timevarying obstacles and avoiding local optimum are two challenges for existing approaches in a dynamic environment.Firstly,a normalized artificial potential field optimization is proposed by reconstructing a novel function with anisotropy in each dimension,which can make the flight speed of a fixed UAV swarm independent of the repulsive/attractive gain coefficient and avoid trapping into local optimization and local oscillation.Then,taking into account minimum velocity and turning angular velocity of fixed-wing UAV swarm,a strategy of decomposing target vector to avoid moving obstacles and pop-up threats is proposed.Finally,several simulations are carried out to illustrate superiority and effectiveness.
基金National Natural Science Foundation of China.Grant ID:11872123.
文摘Projectiles made of reactive structure materials(RSM)can damage the target with not only kinetic but also chemical energy,but the enhanced damage potential of RSM may become compromised if extreme loading condition disintegrates the projectile before the target is reached.In this work,a ductile coating of Ni was introduced to a tungsten-zirconium(W-Zr)alloy,a typical brittle RSM,to preserve the damage potential of the projectile.Detonation driving tests were carried out with X-ray photography and gunpowder deflagration driving tests were carried out with high-speed photography for the coated and uncoated RSM samples,respectively.The craters on the witness target were analyzed by scanning electron microscopy and X-ray diffraction.The Ni coating was found to effectively preserve the damage potential of the W-Zr alloy under extreme loading conditions,whereas the uncoated sample fractured and ignited before impacting the target in both detonation and deflagration driving.The crack propagation between the reactively brittle core and the ductile coating was analyzed based on the crack arrest theory to mechanistically demonstrate how the coating improves the structural integrity and preserves the damage potential of the projectile.Specifically,the Ni coating envelops theW-Zr core until the coated sphere penetrates the target,and the coating is then eroded and worn to release the reactive core for the projectile to damage the target more intensively.
基金Project(2007SK2009)supported by the Science and Technology Research Project of Hunan Province,China
文摘A new anodic material of ternary Pb-0.8%Ag-(0-5.0%)Bi alloy for zinc electrowinning was obtained by doping Bi.The anodic oxygen evolution potential,corrosion rate,surface products after polarization,and microstructures before and after polarization were studied and compared with those of Pb-0.8%Ag anode used in industry.The results show the anodic overpotential decreases with the increase of Bi content in the alloys.When the content of Bi is 1.0%(mass fraction),the anodic overpotential is 40-50 mV lower than that of Pb-0.8%Ag anode.While the corrosion rate decreases and then increases with the increase of Bi content.The Pb-0.8%Ag-0.1%Bi anode has the lowest corrosion rate(0.090 6 mg/(h·cm2).Doping Bi influences the structure of the anodic layer,but does not change the phase.The Pb-0.8%Ag-1.0%Bi anode layer is of a more fine-grained structure compared with Pb-0.8%Ag anode.
基金Project(2014CB239205)supported by the National Basic Research Program of ChinaProject(20011ZX05030-005-003)supported by the National Science and Technology Major Project of China
文摘Faults and fractures of multiple scales are frequently induced and generated in compressional structural system. Comprehensive identification of these potential faults and fractures that cannot be distinguished directly from seismic profile of the complex structures is still an unanswered problem. Based on the compressional structural geometry and kinematics theories as well as the structural interpretation from seismic data, a set of techniques is established for the identification of potential faults and fractures in compressional structures. Firstly, three-dimensional(3D) patterns and characteristics of the faults directly interpreted from seismic profile were illustrated by 3D structural model. Then, the unfolding index maps, the principal structural curvature maps, and tectonic stress field maps were obtained from structural restoration. Moreover, potential faults and fractures in compressional structures were quantitatively identified relying on comprehensive analysis of these three maps. Successful identification of the potential faults and fractures in Mishrif limestone formation and in Asmari dolomite formation of Buzurgan anticline in Iraq demonstrates the applicability and reliability of these techniques.
基金supported by the Industrial Technology Development Program(B1120131046)
文摘The distributed cooperative decision problems of missiles autonomous formation with network packet loss are investigated by using the potential game based on formation principles.In particular,a dynamic target allocation method for missiles formation is provided based on the potential game and formation principles,after the introduction of cooperative guidance and control system of the missiles formation.Then we seek the optimization of a global utility function through autonomous missiles that are capable of making individually rational decisions to optimize their own utility functions.The first important aspect of the problem is to design an individual utility function considering the characteristics of the missiles formation,with which the objective of the missiles are localized to each missile yet aligned with the global utility function.The second is to equip the missiles with an appropriate coordination mechanism with each missile pursuing the optimization of its own utility function.We present the design procedure for the utility,and present a coordination mechanism based on spatial adaptive play and then introduce the idea of“cyclical selected spatial adaptive play”and“negotiation based on time division multiple address(TDMA)protocol formation support network”.Finally,we present simulations for the distributed dynamic target allocation on the comprehensive digital simulation system,and the results illustrate the effectiveness and engineering applicability of the method.
基金Projects(21176264,21476265)supported by the National Natural Science Foundation of China
文摘The pretreatment for the removal of small molecules from poly(acrylic acid) sodium (PAAS) solution by continuous diafiltration was investigated using ultrafiltration membrane. The effects of PAAS concentration, pH, trans-membrane pressure and pretreatment time on the permeate concentration and permeate flux were studied. The results show that the necessary pretreatment time (NPT) increases with PAAS concentration, decreases with TMP. The change trend of permeate flux with time is affected by pH. The permeate fluxes rapidly decrease from the start, and then increase gradually to stable values at pH 5.0, pH 7.0 and pH 9.3. However, it decreases gradually with time till a state value at pH 3.0 (iso-electric point, IEP). The removal of small molecules is easy at pH greater than iso-electric point (IEP). The change of filtration potential with time indicates the similar trend to that of permeation concentration, but the former is more convenient for indication of NPT.
文摘The electrochemical oxidation of galena in collectorless and collector flotation systems, particularly in strong alkaline media, was studied. The results show that, with pH value higher than 12.5 and potentials below 0.17 V, the oxidation products of galena are elemental sulfur and HPbO - 2. Elemental sulfur was present on the mineral surface in excess of oxidized lead species due to dissolution of HPbO - 2, which is beneficial to the flotation of galena. Under the same conditions, sphalerite and pyrite were depressed as a result of significant surface oxidation. Diethyldithiocarbamate (DDTC) was found to be the most suitable collector for galena flotation in strongly alkaline media. The very potential produced hydrophobic PbD 2-the surface reaction product of DDTC with galena, is 0 to 0.2 V. Meantime DDTC can depress the surface over oxidation of galena. Investigations also indicate that, in the range of -0.9 V to 0.6 V, hydrophobic PbD 2 can be firmly adsorbed on galena.
基金Project(51007006) supported by the National Natural Science Foundation of ChinaProject(20090185120023) supported by the Ph.D Programs Foundation for New Teacher of Ministry of Education of China
文摘A potential energy framework for assessment of grid vulnerability was presented.In the framework,the branch potential energy function model was constructed.Two indexes,current vulnerability and forecasting vulnerability,were calculated.The current vulnerability was used to identify the current vulnerable area through calculating the distance between the current transmitted power and initial transmitted power;and the forecast vulnerability under variation of power injection was used to predict the vulnerable area of next step and verify the current vulnerable area.Numerical simulation was performed under variant operating conditions with IEEE-30 bus system,which shows that almost area of 90% overlaps between current vulnerable area and forecasting vulnerable area,the overlapped area is termed as inherent vulnerable area of grid.When considering N-1 contingency,the assessment results of this method proposed agree with those of optimal power flow.When considering N-2 contingency,optimal power flow fails to obtain correct results,while the method based on energy framework gives reliable results.
基金Project(BK20160685)supported by the Science Foundation of Jiangsu Province,ChinaProject(61620106002)supported by the National Natural Science Foundation of China
文摘This study develops new real-time freeway rear-end crash potential predictors using support vector machine(SVM) technique. The relationship between rear-end crash occurrences and traffic conditions were explored using historical loop detector data from Interstate-894 in Milwaukee, Wisconsin, USA. The extracted loop detection data were aggregated over different stations and time intervals to produce explanatory features. A feature selection process, which addresses the interaction between SVM classifiers and explanatory features, was adopted to identify the features that significantly influence rear-end crashes. Afterwards, the identified significant explanatory features over three separate time levels were used to train three SVM models. In the end, the multi-layer perceptron(MLP) artificial neural network models were used as benchmarks to evaluate the performance of SVM models. The results show that the proposed feature selection procedure greatly enhances the accuracy and generalization capability of SVM models. Moreover, the optimal SVM classifier achieves 81.1% overall prediction precision rate. In comparison with MLP artificial neural networks, SVM models provide better results in terms of crash prediction accuracy and false positive rate, which confirms the superior performance of SVM technique in rear-end crash potential prediction analysis.
文摘The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided （into） three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and sulfide mineral-sulfide mineral-collector system. In this paper, taking lead, zinc, iron sulfide mineral systems for examples, several models of galvanic coupling were proposed and the effects of galvanic coupling on flotation were discussed. A galvanic contact between galena （or sphalerite） and pyrite contributes to decreasing the content of zinc in lead concentrate, and enhances remarkably the absorption of collector on the galena surface. During grinding, due to galvanic interactions between minerals and steel medium, Fe（OH）3 formed covers on the cathodic mineral surface, affecting its floatability.
基金Projects(30270496,60075019,60575012)supported by the National Natural Science Foundation of China
文摘A novel method was designed to solve reinforcement learning problems with artificial potential field.Firstly a reinforcement learning problem was transferred to a path planning problem by using artificial potential field(APF),which was a very appropriate method to model a reinforcement learning problem.Secondly,a new APF algorithm was proposed to overcome the local minimum problem in the potential field methods with a virtual water-flow concept.The performance of this new method was tested by a gridworld problem named as key and door maze.The experimental results show that within 45 trials,good and deterministic policies are found in almost all simulations.In comparison with WIERING's HQ-learning system which needs 20 000 trials for stable solution,the proposed new method can obtain optimal and stable policy far more quickly than HQ-learning.Therefore,the new method is simple and effective to give an optimal solution to the reinforcement learning problem.
基金Project(2011ZX05002-005-006) supported by the National Science and Technology Major Research Program during the Twelfth Five-Year Plan of China
文摘The inner relationship between Markov random field(MRF) and Markov chain random field(MCRF) is discussed. MCRF is a special MRF for dealing with high-order interactions of sparse data. It consists of a single spatial Markov chain(SMC) that can move in the whole space. Generally, the theoretical backbone of MCRF is conditional independence assumption, which is a way around the problem of knowing joint probabilities of multi-points. This so-called Naive Bayes assumption should not be taken lightly and should be checked whenever possible because it is mathematically difficult to prove. Rather than trap in this independence proving, an appropriate potential function in MRF theory is chosen instead. The MCRF formulas are well deduced and the joint probability of MRF is presented by localization approach, so that the complicated parameter estimation algorithm and iteration process can be avoided. The MCRF model is then applied to the lithofacies identification of a region and compared with triplex Markov chain(TMC) simulation. Analyses show that the MCRF model will not cause underestimation problem and can better reflect the geological sedimentation process.
基金Projects(51774332,U1932129,51804350,51934009)supported by the National Natural Science Foundation of ChinaProject(2018JJ1041)supported by the Natural Science Foundation of Hunan Province,China。
文摘Chalcopyrite is one of the most important copper minerals;however,the extracted efficiency of chalcopyrite is still not satisfactory in hydrometallurgy owing to its high lattice energy which leads to its low dissolution kinetics.To overcome the difficulties,many advanced technologies have been developed,including the selection of high effectively bacteria,the inhibition of the passivation film adhered onto the minerals surface,and the maintenance of solution redox potential under an optimum range.Up to date,considerable researches on the first two terms have been summarized,while the overview of the last term has been rarely reported.Based on corresponding works in recent years,key trends and roles of solution redox potential in copper hydrometallurgy,including its definition,effect and maintenance,have been introduced in this review.
