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
This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double...This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners.The microstructures of the tungsten layers were analyzed using a scanning electron microscope(SEM).The feasibility analysis was carried out by pulsed X-rays,slug-retrieval test and static penetration tests.The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method.The results showed that the double-layer liners could form well-shaped jets.The errors between the X-ray test results and the numerical results were within 11.07%.A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug.Compared with the traditional pure copper shaped charge jet,the penetration depth of the double-layer shaped charge liner increased by 11.4% and>10.8% respectively.In summary,the test results are good,and the numerical simulation is in good agreement with the test,which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner.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
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
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
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 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
Based on non-Darcian flow law described by exponent and threshold gradient within a double-layered soil, the classic theory of one-dimensional consolidation of double-layered soil was modified to consider the change o...Based on non-Darcian flow law described by exponent and threshold gradient within a double-layered soil, the classic theory of one-dimensional consolidation of double-layered soil was modified to consider the change of vertical total stress with depth and time together. Because of the complexity of governing equations, the numerical solutions were obtained in detail by finite difference method. Then, the numerical solutions were compared with the analytical solutions in condition that non-Darcian flow law was degenerated to Dary's law, and the comparison results show that numerical solutions are reliable. Finally, consolidation behavior of double-layered soil with different parameters was analyzed, and the results show that the consolidation rate of double-layered soil decreases with increasing the value of exponent and threshold of non-Darcian flow, and the exponent and threshold gradient of the first soil layer greatly influence the consolidation rate of double-layered soil. The larger the ratio of the equivalent water head of external load to the total thickness of double-layered soil, the larger the rate of the consolidation, and the similitude relationship in classical consolidation theory of double-layered soil is not satisfied. The other consolidation behavior of double-layered soil with non-Darcian flow is the same as that with Darcy's law.展开更多
To further investigate the one-dimensional(1D)rheological consolidation mechanism of double-layered soil,the fractional derivative Merchant model(FDMM)and the non-Darcian flow model with the non-Newtonian index are re...To further investigate the one-dimensional(1D)rheological consolidation mechanism of double-layered soil,the fractional derivative Merchant model(FDMM)and the non-Darcian flow model with the non-Newtonian index are respectively introduced to describe the deformation of viscoelastic soil and the flow of pore water in the process of consolidation.Accordingly,an 1D rheological consolidation equation of double-layered soil is obtained,and its numerical analysis is performed by the implicit finite difference method.In order to verify its validity,the numerical solutions by the present method for some simplified cases are compared with the results in the related literature.Then,the influence of the revelent parameters on the rheological consolidation of double-layered soil are investigated.Numerical results indicate that the parameters of non-Darcian flow and FDMM of the first soil layer greatly influence the consolidation rate of double-layered soil.As the decrease of relative compressibility or the increase of relative permeability between the lower soil and the upper soil,the dissipation rate of excess pore water pressure and the settlement rate of the ground will be accelerated.Increasing the relative thickness of soil layer with high permeability or low compressibility will also accelerate the consolidation rate of double-layered soil.展开更多
Potential’s fluctuation of rust preventing oil film during its degradation was studied using wirebeam electrode. Being non-destructive and simple, potential measurement is a very repetitive method. Otherelectrochemic...Potential’s fluctuation of rust preventing oil film during its degradation was studied using wirebeam electrode. Being non-destructive and simple, potential measurement is a very repetitive method. Otherelectrochemical testing method, e. g., polarization resistance, can breakdown the integrity of oil coating byDC current; EIS is time consuming. As a special electrochemical sensor, wire beam electrode contains 101wires of mild steel wires, and it is helpful to improve the reproducibility of electrochemical test evidently.Using this electrode, the electrochemical parameters and their distribution which was related to under filmcorrosion process are measured directly so as to describe potential’s fluctuation of rust preventing oil film. Itis pointed out that there is potential’s fluctuation on rust preventing oil film during its degradation, and thischaracteristic has direct effect on the self-repairing ability of rust preventing oil film. However, for the uncoated metal electrode and base oil film, there is no such behavior. It is also pointed out that inhibitors in theoil film have direct effect on its self-repairing ability.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 friction sensitivity(FS) of five aliphatic linear and eight cyclic nitramines has been determined and correlated with DFT B3LYP/6-31-G(d,p) // 6-311+G(d,p) positive(VS,max) and negative(VS,min) extremes of molecul...The friction sensitivity(FS) of five aliphatic linear and eight cyclic nitramines has been determined and correlated with DFT B3LYP/6-31-G(d,p) // 6-311+G(d,p) positive(VS,max) and negative(VS,min) extremes of molecular surface electrostatic potentials VS(r).While there is an ambiguous relationship between the VS,max values and FS values,the decrease of FS is connected(more or less) with increase in VS,min values.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
The time-sequenced damage behavior of the reactive projectile impacting double-layer plates is discussed.The analytical model considering the combined effect of kinetic and chemical energy is developed to reveal the d...The time-sequenced damage behavior of the reactive projectile impacting double-layer plates is discussed.The analytical model considering the combined effect of kinetic and chemical energy is developed to reveal the damage mechanism.The influences of impact velocity and reactive projectile chemical characteristics on the damage effect are decoupled analyzed based on this model.These analyses indicate that the high energy releasing efficiency and fast reaction propagation velocity of the reactive projectile are conducive to enhancing the damage effect.The experiments with various reactive projectiles impact velocity increasing from 702 to 1385 m/s were conducted to verify this model.The experimental results presented that,the damage hole radius of the rear-plate increases with the increase of impact velocity.At the impact velocity of 1350 m/s,the radius of damage hole formed by PTFE/Al/Bi_(2)O_(3),PTFE/Al/MoO_(3),PTFE/Al/Fe_(2)O_(3)projectile on the rear-plate become smaller in sequence.These results are consistent with the analytical model prediction,demonstrating that this model can predict the damage effect quantitatively.This work is of constructive significance to the application of reactive projectiles.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
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
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
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
A spiro-type quaternary ammonium salt, spiro-(1,1′)-bipyrrolidinium tetrafluoroborate(SBP-BF4) was successfully prepared by an economical and efficient three-step process comprising the cyclization reaction of 1,4-di...A spiro-type quaternary ammonium salt, spiro-(1,1′)-bipyrrolidinium tetrafluoroborate(SBP-BF4) was successfully prepared by an economical and efficient three-step process comprising the cyclization reaction of 1,4-dibromobutane and pyrrolidine, and subsequent ion exchange pathway with KOH followed by neutralization reaction via HBF4 in the system of ethanol solution. 1H NMR, 13 C NMR, FI-IR and XPS analyses showed the structure of SBP-BF4. The as-obtained SBP-BF4 was dissolved in AN and used as the electrolyte for supercapacitor. Electrochemical measurements demonstrate that, compared with commercial electrolyte TEMA-BF4/AN, SBP-BF4/AN exhibits high ionic conductivity, lower resistance and improved cycling performance, which is due to its smaller ion size and stable symmetry structure.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
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funded by the China Postdoctoral Science Foundation(Grant No.2022M721614)the opening project of State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology(Grant No.KFJJ23-07M)。
文摘This paper proposes a type of double-layer charge liner fabricated using chemical vapor deposition(CVD)that has tungsten as its inner liner.The feasibility of this design was evaluated through penetration tests.Double-layer charge liners were fabricated by using CVD to deposit tungsten layers on the inner surfaces of pure T2 copper liners.The microstructures of the tungsten layers were analyzed using a scanning electron microscope(SEM).The feasibility analysis was carried out by pulsed X-rays,slug-retrieval test and static penetration tests.The shaped charge jet forming and penetration law of inner tungsten-coated double-layer liner were studied by numerical simulation method.The results showed that the double-layer liners could form well-shaped jets.The errors between the X-ray test results and the numerical results were within 11.07%.A slug-retrieval test was found that the retrieved slug was similar to a numerically simulated slug.Compared with the traditional pure copper shaped charge jet,the penetration depth of the double-layer shaped charge liner increased by 11.4% and>10.8% respectively.In summary,the test results are good,and the numerical simulation is in good agreement with the test,which verified the feasibility of using the CVD method to fabricate double-layer charge liners with a high-density and high-strength refractory metal as the inner liner.
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.
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.
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.
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(50878191,51109092)supported by the National Natural Science Foundation of China
文摘Based on non-Darcian flow law described by exponent and threshold gradient within a double-layered soil, the classic theory of one-dimensional consolidation of double-layered soil was modified to consider the change of vertical total stress with depth and time together. Because of the complexity of governing equations, the numerical solutions were obtained in detail by finite difference method. Then, the numerical solutions were compared with the analytical solutions in condition that non-Darcian flow law was degenerated to Dary's law, and the comparison results show that numerical solutions are reliable. Finally, consolidation behavior of double-layered soil with different parameters was analyzed, and the results show that the consolidation rate of double-layered soil decreases with increasing the value of exponent and threshold of non-Darcian flow, and the exponent and threshold gradient of the first soil layer greatly influence the consolidation rate of double-layered soil. The larger the ratio of the equivalent water head of external load to the total thickness of double-layered soil, the larger the rate of the consolidation, and the similitude relationship in classical consolidation theory of double-layered soil is not satisfied. The other consolidation behavior of double-layered soil with non-Darcian flow is the same as that with Darcy's law.
基金Project(51578511)supported by the National Natural Science Foundation of China。
文摘To further investigate the one-dimensional(1D)rheological consolidation mechanism of double-layered soil,the fractional derivative Merchant model(FDMM)and the non-Darcian flow model with the non-Newtonian index are respectively introduced to describe the deformation of viscoelastic soil and the flow of pore water in the process of consolidation.Accordingly,an 1D rheological consolidation equation of double-layered soil is obtained,and its numerical analysis is performed by the implicit finite difference method.In order to verify its validity,the numerical solutions by the present method for some simplified cases are compared with the results in the related literature.Then,the influence of the revelent parameters on the rheological consolidation of double-layered soil are investigated.Numerical results indicate that the parameters of non-Darcian flow and FDMM of the first soil layer greatly influence the consolidation rate of double-layered soil.As the decrease of relative compressibility or the increase of relative permeability between the lower soil and the upper soil,the dissipation rate of excess pore water pressure and the settlement rate of the ground will be accelerated.Increasing the relative thickness of soil layer with high permeability or low compressibility will also accelerate the consolidation rate of double-layered soil.
文摘Potential’s fluctuation of rust preventing oil film during its degradation was studied using wirebeam electrode. Being non-destructive and simple, potential measurement is a very repetitive method. Otherelectrochemical testing method, e. g., polarization resistance, can breakdown the integrity of oil coating byDC current; EIS is time consuming. As a special electrochemical sensor, wire beam electrode contains 101wires of mild steel wires, and it is helpful to improve the reproducibility of electrochemical test evidently.Using this electrode, the electrochemical parameters and their distribution which was related to under filmcorrosion process are measured directly so as to describe potential’s fluctuation of rust preventing oil film. Itis pointed out that there is potential’s fluctuation on rust preventing oil film during its degradation, and thischaracteristic has direct effect on the self-repairing ability of rust preventing oil film. However, for the uncoated metal electrode and base oil film, there is no such behavior. It is also pointed out that inhibitors in theoil film have direct effect on its self-repairing ability.
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.
基金the project of the Ministry of Education,Youth and Sports of the Czech Republic No.MSM 0021627501
文摘The friction sensitivity(FS) of five aliphatic linear and eight cyclic nitramines has been determined and correlated with DFT B3LYP/6-31-G(d,p) // 6-311+G(d,p) positive(VS,max) and negative(VS,min) extremes of molecular surface electrostatic potentials VS(r).While there is an ambiguous relationship between the VS,max values and FS values,the decrease of FS is connected(more or less) with increase in VS,min values.
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supported by the State Key Program of National Natural Science Foundation of China(Grant No.12132003)State Key Laboratory of Explosion Science and Technology(Grant No.QNKT20-07)。
文摘The time-sequenced damage behavior of the reactive projectile impacting double-layer plates is discussed.The analytical model considering the combined effect of kinetic and chemical energy is developed to reveal the damage mechanism.The influences of impact velocity and reactive projectile chemical characteristics on the damage effect are decoupled analyzed based on this model.These analyses indicate that the high energy releasing efficiency and fast reaction propagation velocity of the reactive projectile are conducive to enhancing the damage effect.The experiments with various reactive projectiles impact velocity increasing from 702 to 1385 m/s were conducted to verify this model.The experimental results presented that,the damage hole radius of the rear-plate increases with the increase of impact velocity.At the impact velocity of 1350 m/s,the radius of damage hole formed by PTFE/Al/Bi_(2)O_(3),PTFE/Al/MoO_(3),PTFE/Al/Fe_(2)O_(3)projectile on the rear-plate become smaller in sequence.These results are consistent with the analytical model prediction,demonstrating that this model can predict the damage effect quantitatively.This work is of constructive significance to the application of reactive projectiles.
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.
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.
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(51371198)supported by the National Natural Science Foundation of China
文摘A spiro-type quaternary ammonium salt, spiro-(1,1′)-bipyrrolidinium tetrafluoroborate(SBP-BF4) was successfully prepared by an economical and efficient three-step process comprising the cyclization reaction of 1,4-dibromobutane and pyrrolidine, and subsequent ion exchange pathway with KOH followed by neutralization reaction via HBF4 in the system of ethanol solution. 1H NMR, 13 C NMR, FI-IR and XPS analyses showed the structure of SBP-BF4. The as-obtained SBP-BF4 was dissolved in AN and used as the electrolyte for supercapacitor. Electrochemical measurements demonstrate that, compared with commercial electrolyte TEMA-BF4/AN, SBP-BF4/AN exhibits high ionic conductivity, lower resistance and improved cycling performance, which is due to its smaller ion size and stable symmetry structure.
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.
