How to effectively evaluate the firing precision of weapon equipment at low cost is one of the core contents of improving the test level of weapon system.A new method to evaluate the firing precision of the MLRS consi...How to effectively evaluate the firing precision of weapon equipment at low cost is one of the core contents of improving the test level of weapon system.A new method to evaluate the firing precision of the MLRS considering the credibility of simulation system based on Bayesian theory is proposed in this paper.First of all,a comprehensive index system for the credibility of the simulation system of the firing precision of the MLRS is constructed combined with the group analytic hierarchy process.A modified method for determining the comprehensive weight of the index is established to improve the rationality of the index weight coefficients.The Bayesian posterior estimation formula of firing precision considering prior information is derived in the form of mixed prior distribution,and the rationality of prior information used in estimation model is discussed quantitatively.With the simulation tests,the different evaluation methods are compared to validate the effectiveness of the proposed method.Finally,the experimental results show that the effectiveness of estimation method for firing precision is improved by more than 25%.展开更多
Evaluation system of small arms firing has an important effect in the context of military domain. A partially automated evaluation system has been conducted and performed at the ground level. Automation of such system...Evaluation system of small arms firing has an important effect in the context of military domain. A partially automated evaluation system has been conducted and performed at the ground level. Automation of such system with the inclusion of artificial intelligence is a much required process. This papers puts focus on designing and developing an AI-based small arms firing evaluation systems in the context of military environment. Initially image processing techniques are used to calculate the target firing score. Additionally, firing errors during the shooting have also been detected using a machine learning algorithm. However, consistency in firing requires an abundance of practice and updated analysis of the previous results. Accuracy and precision are the basic requirements of a good shooter. To test the shooting skill of combatants, firing practices are held by the military personnel at frequent intervals that include 'grouping' and 'shoot to hit' scores. Shortage of skilled personnel and lack of personal interest leads to an inefficient evaluation of the firing standard of a firer. This paper introduces a system that will automatically be able to fetch the target data and evaluate the standard based on the fuzzy systems.Moreover it will be able to predict the shooter performance based on linear regression techniques.Thereby, it compares with recognized patterns to analyze the individual expertise and suggest improvements based on previous values. The paper is developed on a Small Arms Firing Skill Evaluation System, which makes the whole process of firing and target evaluation faster with better accuracy. The experiment has been conducted on real-time scenarios considering the military field and shows a promising result to evaluate the system automatically.展开更多
Considering the fact that memristors have the characteristics similar to biological synapses, a fractional-order multistable memristor is proposed in this paper. It is verified that the fractional-order memristor has ...Considering the fact that memristors have the characteristics similar to biological synapses, a fractional-order multistable memristor is proposed in this paper. It is verified that the fractional-order memristor has multiple local active regions and multiple stable hysteresis loops, and the influence of fractional-order on its nonvolatility is also revealed. Then by considering the fractional-order memristor as an autapse of Hindmarsh–Rose(HR) neuron model, a fractional-order memristive neuron model is developed. The effects of the initial value, external excitation current, coupling strength and fractional-order on the firing behavior are discussed by time series, phase diagram, Lyapunov exponent and inter spike interval(ISI) bifurcation diagram. Three coexisting firing patterns, including irregular asymptotically periodic(A-periodic)bursting, A-periodic bursting and chaotic bursting, dependent on the memristor initial values, are observed. It is also revealed that the fractional-order can not only induce the transition of firing patterns, but also change the firing frequency of the neuron. Finally, a neuron circuit with variable fractional-order is designed to verify the numerical simulations.展开更多
To reduce production costs and make full and reasonable use of raw materials,high alumina bricks were prepared using tabular corundum and mullite as aggregates,sillimanite as intermediate particles,and white fused cor...To reduce production costs and make full and reasonable use of raw materials,high alumina bricks were prepared using tabular corundum and mullite as aggregates,sillimanite as intermediate particles,and white fused corundum powder,α-alumina micropowder,and Suzhou soil as the matrix,firing at different temperatures(1420,1440,1460,1480,1500 and 1520℃)for 4 h.The apparent porosity(AP),the bulk density(BD),the cold crushing strength(CCS),the thermal shock resistance(TSR),the refractoriness under load(RUL)and the creep rate of the samples were tested.The effects of the firing temperature on the creep rate(1450℃×50 h,under a load of 0.2 MPa)of the samples were studied.The results show that with the sillimanite addition of 22.5 mass%,the sample fired at 1460℃for 4 h performs the best comprehensive properties:the AP of 17.5%,the BD of 2.75 g·cm^(-3),the CCS of 100.5 MPa,the TSR number of 35 cycles,the RUL of 1682℃,and the creep rate of-0.428%,which can prolong the service life of furnaces.展开更多
Transforming growth factor-beta 1(TGF-β1)has been extensively studied for its pleiotropic effects on central nervous system diseases.The neuroprotective or neurotoxic effects of TGF-β1 in specific brain areas may de...Transforming growth factor-beta 1(TGF-β1)has been extensively studied for its pleiotropic effects on central nervous system diseases.The neuroprotective or neurotoxic effects of TGF-β1 in specific brain areas may depend on the pathological process and cell types involved.Voltage-gated sodium channels(VGSCs)are essential ion channels for the generation of action potentials in neurons,and are involved in various neuroexcitation-related diseases.However,the effects of TGF-β1 on the functional properties of VGSCs and firing properties in cortical neurons remain unclear.In this study,we investigated the effects of TGF-β1 on VGSC function and firing properties in primary cortical neurons from mice.We found that TGF-β1 increased VGSC current density in a dose-and time-dependent manner,which was attributable to the upregulation of Nav1.3 expression.Increased VGSC current density and Nav1.3 expression were significantly abolished by preincubation with inhibitors of mitogen-activated protein kinase kinase(PD98059),p38 mitogen-activated protein kinase(SB203580),and Jun NH2-terminal kinase 1/2 inhibitor(SP600125).Interestingly,TGF-β1 significantly increased the firing threshold of action potentials but did not change their firing rate in cortical neurons.These findings suggest that TGF-β1 can increase Nav1.3 expression through activation of the ERK1/2-JNK-MAPK pathway,which leads to a decrease in the firing threshold of action potentials in cortical neurons under pathological conditions.Thus,this contributes to the occurrence and progression of neuroexcitatory-related diseases of the central nervous system.展开更多
Neural damage or degeneration is at the crux of many diseases,and treatment of these diseases will require the development of therapeutics to enhance and guide neural regeneration.Both intrinsic and extrinsic factors ...Neural damage or degeneration is at the crux of many diseases,and treatment of these diseases will require the development of therapeutics to enhance and guide neural regeneration.Both intrinsic and extrinsic factors dictate a neuron’s ability to regenerate,and the combination of these factors results in the great regenerative capacity of the peripheral nervous system(PNS)and the poor regenerative capacity of the central nervous system(CNS)following injury.At the core of a neuron’s function is its ability to relay electrochemical signals,and a neuron’s excitability is a key factor in its ability to regenerate.Recent works have focused on the changes in neuronal electrophysiological properties,firing patterns,and ion flux after injury,which differentially activate signaling pathways at the core of regeneration.The role of glia in neuron regeneration has long been studied.展开更多
In order to solve the problem of low efficiency of production systems, a lot of work has been done. The research efforts to improve the performance of production systems are summed up here and future research directio...In order to solve the problem of low efficiency of production systems, a lot of work has been done. The research efforts to improve the performance of production systems are summed up here and future research directions are discussed at last.展开更多
The purpose of this paper is to present the flow field in the 300MW tangential firing utility boiler that used the Low NOx Concentric Firing System (LNCFS). Using the method of cold isothermal simulation ensures the...The purpose of this paper is to present the flow field in the 300MW tangential firing utility boiler that used the Low NOx Concentric Firing System (LNCFS). Using the method of cold isothermal simulation ensures the geometric and boundary condition similarity. At the same time the condition of self-modeling is met. The experimental results show that the mixture of primary air and secondary air becomes slower, the average turbulence magnitude the relative diameter of the tangential firing enlarges of the main combustion zone becomes less and when the secondary air deflection angle increases When the velocity pressure ratio of the secondary air to the primary air (p2/p1) enlarges, the mixture of the secondary air and the primary air becomes stronger, the average turbulence magnitude of the main combustion zone increases, and the relative diameter of the tangential firing becomes larger. Because the over fire air (OFA) laid out near the wall has a powerful penetration, the relative diameter of the tangential firing on the section of the OFA is very little, but the average turbulence magnitude is great. When the velocity pressure ratio of the OFA to the primary air POFA/p1 increases, the relative diameter of the tangential firing on the section of the OFA grows little, the average turbulence magnitude becomes larger and the penetration of the OFA becomes more powerful.展开更多
Recent advances in the experimental and theoretical study of dynamics of neuronal electrical firing activities are reviewed. Firstly, some experimental phenomena of neuronal irregular firing patterns, especially chaot...Recent advances in the experimental and theoretical study of dynamics of neuronal electrical firing activities are reviewed. Firstly, some experimental phenomena of neuronal irregular firing patterns, especially chaotic and stochastic firing patterns, are presented, and practical nonlinear time analysis methods are introduced to distinguish deterministic and stochastic mechanism in time series. Secondly, the dynamics of electrical firing activities in a single neuron is concerned, namely, fast-slow dynamics analysis for classification and mechanism of various bursting patterns, one- or two-parameter bifurcation analysis for transitions of firing patterns, and stochastic dynamics of firing activities (stochastic and coherence resonances, integer multiple and other firing patterns induced by noise, etc.). Thirdly, different types of synchronization of coupled neurons with electrical and chemical synapses are discussed. As noise and time delay are inevitable in nervous systems, it is found that noise and time delay may induce or enhance synchronization and change firing patterns of coupled neurons. Noise-induced resonance and spatiotemporal patterns in coupled neuronal networks are also demonstrated. Finally, some prospects are presented for future research. In consequence, the idea and methods of nonlinear dynamics are of great significance in exploration of dynamic processes and physiological functions of nervous systems.展开更多
Microelectrode technique was used to record the spontaneous electrical activities of the neurons in olfactory bulb of the Bufo bufo gargarizans, both in hibernation and after hibemation. This study investigated the el...Microelectrode technique was used to record the spontaneous electrical activities of the neurons in olfactory bulb of the Bufo bufo gargarizans, both in hibernation and after hibemation. This study investigated the electrophysiological characteristics of amphibian olfactory bulb in the period of hibernation and after hibernation and its effects on the start of hibernation and spontaneous awakening. The research showed four forms of spontaneous firings: single spontaneous firing, burst spontaneous firing, irregular spontaneous firing and consecutive single spontaneous firing. The single spontaneous firing includes slow depolarized spontaneous firing and fast depolarized spontaneous firing, and the slow depolarized spontaneous firing occurs only during the hibernation period. In hibernation, the low amplitude and low frequency firing with a longer duration may be relevant to maintaining the tonicity of the central nervous system in toads that are in hibernation, and this kind of firing may also provide an excited basis for their arousal from hibernation. After hibernation, the amplitude and frequency of firing increase, but the firing duration gets shorter. This form of short-term firing, which may be a phenomenon of sensory neurons fast adapting, is one of the neuronal mechanisms for the arousal of hibernating animals.展开更多
The γ-aminobutyric acid neurons(GABAergic neurons) in the inferior colliculus are classified into various patterns based on their intrinsic electrical properties to a constant current injection. Although this class...The γ-aminobutyric acid neurons(GABAergic neurons) in the inferior colliculus are classified into various patterns based on their intrinsic electrical properties to a constant current injection. Although this classification is associated with physiological function, the exact role for neurons with various firing patterns in acoustic processing remains poorly understood. In the present study, we analyzed characteristics of inferior colliculus neurons in vitro, and recorded responses to stimulation of the dorsal nucleus of the lateral lemniscus using the wholecell patch clamp technique. Seven inferior colliculus neurons were tested and were classified into two firing patterns: sustained-regular(n = 4) and sustained-adapting firing patterns(n = 3). The majority of inferior colliculus neurons exhibited slight changes in response to stimulation and bicuculline. The responses of one neuron with a sustained-adapting firing pattern were suppressed after stimulation, but recovered to normal levels following application of the γ-aminobutyric acid receptor antagonist. One neuron with a sustained-regular pattern showed suppressed stimulation responses, which were not affected by bicuculline. Results suggest that GABAergic neurons in the inferior colliculus exhibit sustained-regular or sustained-adapting firing patterns. Additionally, GABAergic projections from the dorsal nucleus of the lateral lemniscus to the inferior colliculus are associated with sound localization. The different neuronal responses of various firing patterns suggest a role in sound localization. A better understanding of these mechanisms and functions will provide better clinical treatment paradigms for hearing deficiencies.展开更多
Forest ecosystems are our priceless natural resource and are a key component of the global carbon budget. Forest fires can be a hazard to the viability and sustainable management of forests with consequences for natur...Forest ecosystems are our priceless natural resource and are a key component of the global carbon budget. Forest fires can be a hazard to the viability and sustainable management of forests with consequences for natural and cultural environments, economies, and the life quality of local and regional populations. Thus, the selection of strategies to manage forest fires, while considering both functional and economic efficiency, is of primary importance. The use of decision support systems(DSSs) by managers of forest fires has rapidly increased. This has strengthened capacity to prevent and suppress forest fires while protecting human lives and property. DSSs are a tool that can benefit incident management and decision making and policy, especially for emergencies such as natural disasters. In this study we reviewed state-of-the-art DSSs that use: database management systems and mathematical/economic algorithms for spatial optimization of firefighting forces; forest fire simulators and satellite technology for immediate detection and prediction of evolution of forest fires; GIS platforms that incorporate several tools to manipulate, process and analyze geographic data and develop strategic and operational plans.展开更多
In this paper,based on the topological description method,the kinematic and dynamic equations of the projectile flight and projectile-artillery coupling system during the whole process of firing are constructed.The fa...In this paper,based on the topological description method,the kinematic and dynamic equations of the projectile flight and projectile-artillery coupling system during the whole process of firing are constructed.The factors that can affect the projectile burst points,namely the state parameters of the projectile on the muzzle and state parameters of the barrel muzzle,as well as the factors that affect the barrel muzzle state parameters,are analyzed.On this basis,the design principle of artillery firing accuracy is proposed.The error analysis and the corresponding inverse problem,the extraction method of key parameters affecting artillery implicated motion,the conformal and control method of rotating band are analyzed and presented.Finally,the presented method is verified through a vehicle mounted howitzer case,and the muzzle state parameter interval is obtained meeting the given firing accuracy.In addition,the sensitivity analysis of artillery parameters shows that the less the correlation between the parameters and the barrel,the less the influence on the projectile implicated motion.The analysis of the coupling effect between rifling and the rotating band shows that the uniform rifling is the optimal form for the conformal of the rotating band during firing.展开更多
Intermittent new energy delivery requires increasing the flexibility of ultra-high voltage direct current(DC)power adjustment.Based on a converter steady-state model and a DC power model,the control angle constraints ...Intermittent new energy delivery requires increasing the flexibility of ultra-high voltage direct current(DC)power adjustment.Based on a converter steady-state model and a DC power model,the control angle constraints of a converter valve are relaxed for power regulation.In this paper,a flexible DC power control method based on a fixed tap changer position is proposed.The initial ratio of the converter transformer is optimized.The effects of the fixed-tap changer position control on the control angle,reactive power compensation,and commutation failure are analyzed.The new control method allows a DC system to operate at a large angle and increase the additional reactive power loss while improving the commutation security margin.Steady-state and electromagnetic transient simulations in the CIGRE test system verify the validity of the method proposed in this paper and the correctness of the analysis conclusions.展开更多
Objective To explore the possible mechanisms that cause the dentate gyrus (DG) neurons to play different roles in information coding. Methods In vivo extracellular single unit recording was performed on 22 waking fe...Objective To explore the possible mechanisms that cause the dentate gyrus (DG) neurons to play different roles in information coding. Methods In vivo extracellular single unit recording was performed on 22 waking female guinea pigs, which were positioned in a sound-attenuated recording chamber without any muscular relaxants. The spontaneous firing patterns of the DG neurons were detected and compared. Results There were two different electrophysiologi- cal populations in the DG of guinea pigs, principal cells (PCs) and fast spiking interneurons (INs). Of the PCs, 1.3% discharged regularly, 48.1% irregularly and 50.6% in bursts ; in contrast, of the INs units, 64.1% discharged regularly, 2.6% irregularly and 33.3% in bursts. The spontaneous firing patterns of PCs were significantly different from those of INs (P 〈0.01 ). In addition, the differences of several interspike interval (ISI) parameters also have been observed: (1) the ISI coefficients of variation of PCs (3.39 ± 3.56) were significantly higher than those of INs (1.08 ± 0.46) (P 〈0.01) ; (2) the ISI asymmetric indexes of PCs (0. 047±0. 059) were significantly lower than those of INs (0.569±0. 238) (P 〈 0.01 ). Conclusion In the DG, the spontaneous firing patterns of PCs were significantly different from those of INs. The former were prone to fire in bursts, the latter were prone to fire regularly. The different roles in information coding between PCs and INs might be caused by their different firing patterns.展开更多
Thermal safety of modular charge which is fed into and retained in the chamber after gun fires consecutively is first investigated with cook-off method,A two-dimensional cook-off model of modular charge in gun chamber...Thermal safety of modular charge which is fed into and retained in the chamber after gun fires consecutively is first investigated with cook-off method,A two-dimensional cook-off model of modular charge in gun chamber is established and the cook-off process of modular charge in gun chamber is numerically simulated.Then the effects of module number and firing condition on charge thermal safety are evaluated by researching the cook-off response characteristics of modules.The results show that under conditions of different module numbers the cook-off responses all occur on the module closest to the boundary of missile,and the single-base propellants located at the inner surface of cartridge ignite first.When the number of loaded module changes from 1 to 6,the cook-off response temperatures vary little,only in a small range of 478.1 K-482.4 K.The cook-off response times decrease logarithmically in the range of 211.25-166.7 s with the increasing length of residual air gap in gun chamber.The simulation results are well matched with the experimental data.Furthermore,different firing conditions have greatinfluence on the cook-off response time,minor influence on the initial response position and little in-fluence on the response temperature.Under the three conditions of consecutive 32 launches with 5 rounds/min,43 launches with 1 round/min,and 41 launches with different firing frequencies,the cook off response temperatures are 479.2 K,481.1 K and 479.9 K respectively and the response times are 709.25,211.2 s and 214.4 s respectively.The response position is near the middle area of the inner cartridge surface in the former condition and near the right area in the latter two conditions.展开更多
The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation, but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown....The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation, but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown. Computational neuroscience studies indicate that high-frequency bursts in stimulus-driven responses can be transmitted across synapses more reliably than isolated spikes, and thus may carry accurate stimulus-related information. Our research examined whether or not adaptation affects the burst firing property of visual cortical neurons by examining changes in the burst firing changes of V1 neurons during adaptation to the preferred visual stimulus. The results show that adaptation to prolonged visual stimulation significantly decreased burst frequency (bursts/s) and burst length (spikes/burst), but increased burst duration and the interspike interval within bursts. These results suggest that the adaptation of V1 neurons to visual stimulation may result in a decrease of feedforward response gain but an increase of functional activities from lateral and/or feedback connections, which could lead to a reduction in the effectiveness of adapted neurons in transmitting information to its driven neurons.展开更多
Autapses are synapses that connect a neuron to itself in the nervous system. Previously, both experimental and theoretical studies have demonstrated that autaptic connections in the nervous system have a significant p...Autapses are synapses that connect a neuron to itself in the nervous system. Previously, both experimental and theoretical studies have demonstrated that autaptic connections in the nervous system have a significant physiological function. Autapses in nature provide self-delayed feedback, thus introducing an additional timescale to neuronal activities and causing many dynamic behaviors in neurons. Recently, theoretical studies have revealed that an autapse provides a control option for adjusting the response of a neuron: e.g., an autaptic connection can cause the electrical activities of the Hindmarsh–Rose neuron to switch between quiescent, periodic, and chaotic firing patterns; an autapse can enhance or suppress the mode-locking status of a neuron injected with sinusoidal current; and the firing frequency and interspike interval distributions of the response spike train can also be modified by the autapse. In this paper, we review recent studies that showed how an autapse affects the response of a single neuron.展开更多
Technology for safe firing area maps was introduced firstly,and then potential danger after the launching of shells by an antiaircraft gun and a rocket was analyzed.Finally,problems in the process of applying the regu...Technology for safe firing area maps was introduced firstly,and then potential danger after the launching of shells by an antiaircraft gun and a rocket was analyzed.Finally,problems in the process of applying the regulations and their solutions were discussed.The application of safe firing area maps can provide technical support for the efficient development of weather modification operation.展开更多
The devastating effects of wildland fire are an unsolved problem,resulting in human losses and the destruction of natural and economic resources.Convolutional neural network(CNN)is shown to perform very well in the ar...The devastating effects of wildland fire are an unsolved problem,resulting in human losses and the destruction of natural and economic resources.Convolutional neural network(CNN)is shown to perform very well in the area of object classification.This network has the ability to perform feature extraction and classification within the same architecture.In this paper,we propose a CNN for identifying fire in videos.A deep domain based method for video fire detection is proposed to extract a powerful feature representation of fire.Testing on real video sequences,the proposed approach achieves better classification performance as some of relevant conventional video based fire detection methods and indicates that using CNN to detect fire in videos is efficient.To balance the efficiency and accuracy,the model is fine-tuned considering the nature of the target problem and fire data.Experimental results on benchmark fire datasets reveal the effectiveness of the proposed framework and validate its suitability for fire detection in closed-circuit television surveillance systems compared to state-of-the-art methods.展开更多
基金National Natural Science Foundation of China(Grant Nos.11972193 and 92266201)。
文摘How to effectively evaluate the firing precision of weapon equipment at low cost is one of the core contents of improving the test level of weapon system.A new method to evaluate the firing precision of the MLRS considering the credibility of simulation system based on Bayesian theory is proposed in this paper.First of all,a comprehensive index system for the credibility of the simulation system of the firing precision of the MLRS is constructed combined with the group analytic hierarchy process.A modified method for determining the comprehensive weight of the index is established to improve the rationality of the index weight coefficients.The Bayesian posterior estimation formula of firing precision considering prior information is derived in the form of mixed prior distribution,and the rationality of prior information used in estimation model is discussed quantitatively.With the simulation tests,the different evaluation methods are compared to validate the effectiveness of the proposed method.Finally,the experimental results show that the effectiveness of estimation method for firing precision is improved by more than 25%.
文摘Evaluation system of small arms firing has an important effect in the context of military domain. A partially automated evaluation system has been conducted and performed at the ground level. Automation of such system with the inclusion of artificial intelligence is a much required process. This papers puts focus on designing and developing an AI-based small arms firing evaluation systems in the context of military environment. Initially image processing techniques are used to calculate the target firing score. Additionally, firing errors during the shooting have also been detected using a machine learning algorithm. However, consistency in firing requires an abundance of practice and updated analysis of the previous results. Accuracy and precision are the basic requirements of a good shooter. To test the shooting skill of combatants, firing practices are held by the military personnel at frequent intervals that include 'grouping' and 'shoot to hit' scores. Shortage of skilled personnel and lack of personal interest leads to an inefficient evaluation of the firing standard of a firer. This paper introduces a system that will automatically be able to fetch the target data and evaluate the standard based on the fuzzy systems.Moreover it will be able to predict the shooter performance based on linear regression techniques.Thereby, it compares with recognized patterns to analyze the individual expertise and suggest improvements based on previous values. The paper is developed on a Small Arms Firing Skill Evaluation System, which makes the whole process of firing and target evaluation faster with better accuracy. The experiment has been conducted on real-time scenarios considering the military field and shows a promising result to evaluate the system automatically.
基金Project supported by the National Key Research and Development Program of China (Grant No.2018AAA0103300)the National Natural Science Foundation of China (Grant Nos.62171401 and 62071411)。
文摘Considering the fact that memristors have the characteristics similar to biological synapses, a fractional-order multistable memristor is proposed in this paper. It is verified that the fractional-order memristor has multiple local active regions and multiple stable hysteresis loops, and the influence of fractional-order on its nonvolatility is also revealed. Then by considering the fractional-order memristor as an autapse of Hindmarsh–Rose(HR) neuron model, a fractional-order memristive neuron model is developed. The effects of the initial value, external excitation current, coupling strength and fractional-order on the firing behavior are discussed by time series, phase diagram, Lyapunov exponent and inter spike interval(ISI) bifurcation diagram. Three coexisting firing patterns, including irregular asymptotically periodic(A-periodic)bursting, A-periodic bursting and chaotic bursting, dependent on the memristor initial values, are observed. It is also revealed that the fractional-order can not only induce the transition of firing patterns, but also change the firing frequency of the neuron. Finally, a neuron circuit with variable fractional-order is designed to verify the numerical simulations.
文摘To reduce production costs and make full and reasonable use of raw materials,high alumina bricks were prepared using tabular corundum and mullite as aggregates,sillimanite as intermediate particles,and white fused corundum powder,α-alumina micropowder,and Suzhou soil as the matrix,firing at different temperatures(1420,1440,1460,1480,1500 and 1520℃)for 4 h.The apparent porosity(AP),the bulk density(BD),the cold crushing strength(CCS),the thermal shock resistance(TSR),the refractoriness under load(RUL)and the creep rate of the samples were tested.The effects of the firing temperature on the creep rate(1450℃×50 h,under a load of 0.2 MPa)of the samples were studied.The results show that with the sillimanite addition of 22.5 mass%,the sample fired at 1460℃for 4 h performs the best comprehensive properties:the AP of 17.5%,the BD of 2.75 g·cm^(-3),the CCS of 100.5 MPa,the TSR number of 35 cycles,the RUL of 1682℃,and the creep rate of-0.428%,which can prolong the service life of furnaces.
基金supported by the Natural Science Foundation of Guangdong Province,Nos.2019A1515010649(to WC),2022A1515012044(to JS)the China Postdoctoral Science Foundation,No.2018M633091(to JS).
文摘Transforming growth factor-beta 1(TGF-β1)has been extensively studied for its pleiotropic effects on central nervous system diseases.The neuroprotective or neurotoxic effects of TGF-β1 in specific brain areas may depend on the pathological process and cell types involved.Voltage-gated sodium channels(VGSCs)are essential ion channels for the generation of action potentials in neurons,and are involved in various neuroexcitation-related diseases.However,the effects of TGF-β1 on the functional properties of VGSCs and firing properties in cortical neurons remain unclear.In this study,we investigated the effects of TGF-β1 on VGSC function and firing properties in primary cortical neurons from mice.We found that TGF-β1 increased VGSC current density in a dose-and time-dependent manner,which was attributable to the upregulation of Nav1.3 expression.Increased VGSC current density and Nav1.3 expression were significantly abolished by preincubation with inhibitors of mitogen-activated protein kinase kinase(PD98059),p38 mitogen-activated protein kinase(SB203580),and Jun NH2-terminal kinase 1/2 inhibitor(SP600125).Interestingly,TGF-β1 significantly increased the firing threshold of action potentials but did not change their firing rate in cortical neurons.These findings suggest that TGF-β1 can increase Nav1.3 expression through activation of the ERK1/2-JNK-MAPK pathway,which leads to a decrease in the firing threshold of action potentials in cortical neurons under pathological conditions.Thus,this contributes to the occurrence and progression of neuroexcitatory-related diseases of the central nervous system.
文摘Neural damage or degeneration is at the crux of many diseases,and treatment of these diseases will require the development of therapeutics to enhance and guide neural regeneration.Both intrinsic and extrinsic factors dictate a neuron’s ability to regenerate,and the combination of these factors results in the great regenerative capacity of the peripheral nervous system(PNS)and the poor regenerative capacity of the central nervous system(CNS)following injury.At the core of a neuron’s function is its ability to relay electrochemical signals,and a neuron’s excitability is a key factor in its ability to regenerate.Recent works have focused on the changes in neuronal electrophysiological properties,firing patterns,and ion flux after injury,which differentially activate signaling pathways at the core of regeneration.The role of glia in neuron regeneration has long been studied.
文摘In order to solve the problem of low efficiency of production systems, a lot of work has been done. The research efforts to improve the performance of production systems are summed up here and future research directions are discussed at last.
基金This paper is supported by National Natural Science Foundation of China under Grant No50476050Natural Science Basic Research Plan in Shaanxi Province of China under Grant No2005E221
文摘The purpose of this paper is to present the flow field in the 300MW tangential firing utility boiler that used the Low NOx Concentric Firing System (LNCFS). Using the method of cold isothermal simulation ensures the geometric and boundary condition similarity. At the same time the condition of self-modeling is met. The experimental results show that the mixture of primary air and secondary air becomes slower, the average turbulence magnitude the relative diameter of the tangential firing enlarges of the main combustion zone becomes less and when the secondary air deflection angle increases When the velocity pressure ratio of the secondary air to the primary air (p2/p1) enlarges, the mixture of the secondary air and the primary air becomes stronger, the average turbulence magnitude of the main combustion zone increases, and the relative diameter of the tangential firing becomes larger. Because the over fire air (OFA) laid out near the wall has a powerful penetration, the relative diameter of the tangential firing on the section of the OFA is very little, but the average turbulence magnitude is great. When the velocity pressure ratio of the OFA to the primary air POFA/p1 increases, the relative diameter of the tangential firing on the section of the OFA grows little, the average turbulence magnitude becomes larger and the penetration of the OFA becomes more powerful.
基金the National Natural Science Foundation of China (10432010,10702002,10772101,10802012)the National High Technology Research and Development Program (2007AA02Z310)
文摘Recent advances in the experimental and theoretical study of dynamics of neuronal electrical firing activities are reviewed. Firstly, some experimental phenomena of neuronal irregular firing patterns, especially chaotic and stochastic firing patterns, are presented, and practical nonlinear time analysis methods are introduced to distinguish deterministic and stochastic mechanism in time series. Secondly, the dynamics of electrical firing activities in a single neuron is concerned, namely, fast-slow dynamics analysis for classification and mechanism of various bursting patterns, one- or two-parameter bifurcation analysis for transitions of firing patterns, and stochastic dynamics of firing activities (stochastic and coherence resonances, integer multiple and other firing patterns induced by noise, etc.). Thirdly, different types of synchronization of coupled neurons with electrical and chemical synapses are discussed. As noise and time delay are inevitable in nervous systems, it is found that noise and time delay may induce or enhance synchronization and change firing patterns of coupled neurons. Noise-induced resonance and spatiotemporal patterns in coupled neuronal networks are also demonstrated. Finally, some prospects are presented for future research. In consequence, the idea and methods of nonlinear dynamics are of great significance in exploration of dynamic processes and physiological functions of nervous systems.
基金Liaoning Provincial Department of Education-Funded Project, No. 20068040the Experimental Center of Shenyang Normal University Foundation, No. 2008007
文摘Microelectrode technique was used to record the spontaneous electrical activities of the neurons in olfactory bulb of the Bufo bufo gargarizans, both in hibernation and after hibemation. This study investigated the electrophysiological characteristics of amphibian olfactory bulb in the period of hibernation and after hibernation and its effects on the start of hibernation and spontaneous awakening. The research showed four forms of spontaneous firings: single spontaneous firing, burst spontaneous firing, irregular spontaneous firing and consecutive single spontaneous firing. The single spontaneous firing includes slow depolarized spontaneous firing and fast depolarized spontaneous firing, and the slow depolarized spontaneous firing occurs only during the hibernation period. In hibernation, the low amplitude and low frequency firing with a longer duration may be relevant to maintaining the tonicity of the central nervous system in toads that are in hibernation, and this kind of firing may also provide an excited basis for their arousal from hibernation. After hibernation, the amplitude and frequency of firing increase, but the firing duration gets shorter. This form of short-term firing, which may be a phenomenon of sensory neurons fast adapting, is one of the neuronal mechanisms for the arousal of hibernating animals.
基金supported by the National Natural Science Foundation of China,No.81271090
文摘The γ-aminobutyric acid neurons(GABAergic neurons) in the inferior colliculus are classified into various patterns based on their intrinsic electrical properties to a constant current injection. Although this classification is associated with physiological function, the exact role for neurons with various firing patterns in acoustic processing remains poorly understood. In the present study, we analyzed characteristics of inferior colliculus neurons in vitro, and recorded responses to stimulation of the dorsal nucleus of the lateral lemniscus using the wholecell patch clamp technique. Seven inferior colliculus neurons were tested and were classified into two firing patterns: sustained-regular(n = 4) and sustained-adapting firing patterns(n = 3). The majority of inferior colliculus neurons exhibited slight changes in response to stimulation and bicuculline. The responses of one neuron with a sustained-adapting firing pattern were suppressed after stimulation, but recovered to normal levels following application of the γ-aminobutyric acid receptor antagonist. One neuron with a sustained-regular pattern showed suppressed stimulation responses, which were not affected by bicuculline. Results suggest that GABAergic neurons in the inferior colliculus exhibit sustained-regular or sustained-adapting firing patterns. Additionally, GABAergic projections from the dorsal nucleus of the lateral lemniscus to the inferior colliculus are associated with sound localization. The different neuronal responses of various firing patterns suggest a role in sound localization. A better understanding of these mechanisms and functions will provide better clinical treatment paradigms for hearing deficiencies.
基金co-financed by the European Union(European Social Fund-ESF)and Greek national funds through the Operational Program‘‘Education and Lifelong Learning’’of the National Strategic Reference Framework(NSRF)-Research Funding Program:Thales.Investing in knowledge society through the European Social Fund
文摘Forest ecosystems are our priceless natural resource and are a key component of the global carbon budget. Forest fires can be a hazard to the viability and sustainable management of forests with consequences for natural and cultural environments, economies, and the life quality of local and regional populations. Thus, the selection of strategies to manage forest fires, while considering both functional and economic efficiency, is of primary importance. The use of decision support systems(DSSs) by managers of forest fires has rapidly increased. This has strengthened capacity to prevent and suppress forest fires while protecting human lives and property. DSSs are a tool that can benefit incident management and decision making and policy, especially for emergencies such as natural disasters. In this study we reviewed state-of-the-art DSSs that use: database management systems and mathematical/economic algorithms for spatial optimization of firefighting forces; forest fire simulators and satellite technology for immediate detection and prediction of evolution of forest fires; GIS platforms that incorporate several tools to manipulate, process and analyze geographic data and develop strategic and operational plans.
基金This work was supported by the Natural Science Foundation of China(Grant No.11472137)the Fundamental Research Funds for the Central University(Grant No.309181A880 and 30919011204).
文摘In this paper,based on the topological description method,the kinematic and dynamic equations of the projectile flight and projectile-artillery coupling system during the whole process of firing are constructed.The factors that can affect the projectile burst points,namely the state parameters of the projectile on the muzzle and state parameters of the barrel muzzle,as well as the factors that affect the barrel muzzle state parameters,are analyzed.On this basis,the design principle of artillery firing accuracy is proposed.The error analysis and the corresponding inverse problem,the extraction method of key parameters affecting artillery implicated motion,the conformal and control method of rotating band are analyzed and presented.Finally,the presented method is verified through a vehicle mounted howitzer case,and the muzzle state parameter interval is obtained meeting the given firing accuracy.In addition,the sensitivity analysis of artillery parameters shows that the less the correlation between the parameters and the barrel,the less the influence on the projectile implicated motion.The analysis of the coupling effect between rifling and the rotating band shows that the uniform rifling is the optimal form for the conformal of the rotating band during firing.
基金an independent research project from the Shandong Electric Power Research Institute,“Research on the control method of DC power under fixed converter transformer tap-changer position”(ZY-2020-01)Based on the achievement,a national invention patent(No.2020112240143)has been applied.
文摘Intermittent new energy delivery requires increasing the flexibility of ultra-high voltage direct current(DC)power adjustment.Based on a converter steady-state model and a DC power model,the control angle constraints of a converter valve are relaxed for power regulation.In this paper,a flexible DC power control method based on a fixed tap changer position is proposed.The initial ratio of the converter transformer is optimized.The effects of the fixed-tap changer position control on the control angle,reactive power compensation,and commutation failure are analyzed.The new control method allows a DC system to operate at a large angle and increase the additional reactive power loss while improving the commutation security margin.Steady-state and electromagnetic transient simulations in the CIGRE test system verify the validity of the method proposed in this paper and the correctness of the analysis conclusions.
文摘Objective To explore the possible mechanisms that cause the dentate gyrus (DG) neurons to play different roles in information coding. Methods In vivo extracellular single unit recording was performed on 22 waking female guinea pigs, which were positioned in a sound-attenuated recording chamber without any muscular relaxants. The spontaneous firing patterns of the DG neurons were detected and compared. Results There were two different electrophysiologi- cal populations in the DG of guinea pigs, principal cells (PCs) and fast spiking interneurons (INs). Of the PCs, 1.3% discharged regularly, 48.1% irregularly and 50.6% in bursts ; in contrast, of the INs units, 64.1% discharged regularly, 2.6% irregularly and 33.3% in bursts. The spontaneous firing patterns of PCs were significantly different from those of INs (P 〈0.01 ). In addition, the differences of several interspike interval (ISI) parameters also have been observed: (1) the ISI coefficients of variation of PCs (3.39 ± 3.56) were significantly higher than those of INs (1.08 ± 0.46) (P 〈0.01) ; (2) the ISI asymmetric indexes of PCs (0. 047±0. 059) were significantly lower than those of INs (0.569±0. 238) (P 〈 0.01 ). Conclusion In the DG, the spontaneous firing patterns of PCs were significantly different from those of INs. The former were prone to fire in bursts, the latter were prone to fire regularly. The different roles in information coding between PCs and INs might be caused by their different firing patterns.
文摘Thermal safety of modular charge which is fed into and retained in the chamber after gun fires consecutively is first investigated with cook-off method,A two-dimensional cook-off model of modular charge in gun chamber is established and the cook-off process of modular charge in gun chamber is numerically simulated.Then the effects of module number and firing condition on charge thermal safety are evaluated by researching the cook-off response characteristics of modules.The results show that under conditions of different module numbers the cook-off responses all occur on the module closest to the boundary of missile,and the single-base propellants located at the inner surface of cartridge ignite first.When the number of loaded module changes from 1 to 6,the cook-off response temperatures vary little,only in a small range of 478.1 K-482.4 K.The cook-off response times decrease logarithmically in the range of 211.25-166.7 s with the increasing length of residual air gap in gun chamber.The simulation results are well matched with the experimental data.Furthermore,different firing conditions have greatinfluence on the cook-off response time,minor influence on the initial response position and little in-fluence on the response temperature.Under the three conditions of consecutive 32 launches with 5 rounds/min,43 launches with 1 round/min,and 41 launches with different firing frequencies,the cook off response temperatures are 479.2 K,481.1 K and 479.9 K respectively and the response times are 709.25,211.2 s and 214.4 s respectively.The response position is near the middle area of the inner cartridge surface in the former condition and near the right area in the latter two conditions.
基金supported by the National Natural Science Foundation of China (31171082)the Natural Science Foundation of Anhui Province (070413138)+1 种基金the Key Research Foundation of the Anhui Provincial Education Department (KJ2009A167)the Foundation of Key Laboratories of Anhui Province and the Anhui Provincial Education Department
文摘The mean firing rate of visual cortical neurons is reduced after prolonged visual stimulation, but the underlying process by which this occurs as well as the biological significance of this phenomenon remains unknown. Computational neuroscience studies indicate that high-frequency bursts in stimulus-driven responses can be transmitted across synapses more reliably than isolated spikes, and thus may carry accurate stimulus-related information. Our research examined whether or not adaptation affects the burst firing property of visual cortical neurons by examining changes in the burst firing changes of V1 neurons during adaptation to the preferred visual stimulus. The results show that adaptation to prolonged visual stimulation significantly decreased burst frequency (bursts/s) and burst length (spikes/burst), but increased burst duration and the interspike interval within bursts. These results suggest that the adaptation of V1 neurons to visual stimulation may result in a decrease of feedforward response gain but an increase of functional activities from lateral and/or feedback connections, which could lead to a reduction in the effectiveness of adapted neurons in transmitting information to its driven neurons.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11275084 and 11447027)the Fundamental Research Funds for the Central UniversitiesChina(Grant No.GK201503025)
文摘Autapses are synapses that connect a neuron to itself in the nervous system. Previously, both experimental and theoretical studies have demonstrated that autaptic connections in the nervous system have a significant physiological function. Autapses in nature provide self-delayed feedback, thus introducing an additional timescale to neuronal activities and causing many dynamic behaviors in neurons. Recently, theoretical studies have revealed that an autapse provides a control option for adjusting the response of a neuron: e.g., an autaptic connection can cause the electrical activities of the Hindmarsh–Rose neuron to switch between quiescent, periodic, and chaotic firing patterns; an autapse can enhance or suppress the mode-locking status of a neuron injected with sinusoidal current; and the firing frequency and interspike interval distributions of the response spike train can also be modified by the autapse. In this paper, we review recent studies that showed how an autapse affects the response of a single neuron.
基金Supported by Project for Research on Meteorological Science and Technology of Weifang Meteorological Bureau(2016wfqxkt04)
文摘Technology for safe firing area maps was introduced firstly,and then potential danger after the launching of shells by an antiaircraft gun and a rocket was analyzed.Finally,problems in the process of applying the regulations and their solutions were discussed.The application of safe firing area maps can provide technical support for the efficient development of weather modification operation.
基金National Natural Science Foundation of China(No.61573095)Natural Science Foundation of Shanghai,China(No.6ZR1446700)
文摘The devastating effects of wildland fire are an unsolved problem,resulting in human losses and the destruction of natural and economic resources.Convolutional neural network(CNN)is shown to perform very well in the area of object classification.This network has the ability to perform feature extraction and classification within the same architecture.In this paper,we propose a CNN for identifying fire in videos.A deep domain based method for video fire detection is proposed to extract a powerful feature representation of fire.Testing on real video sequences,the proposed approach achieves better classification performance as some of relevant conventional video based fire detection methods and indicates that using CNN to detect fire in videos is efficient.To balance the efficiency and accuracy,the model is fine-tuned considering the nature of the target problem and fire data.Experimental results on benchmark fire datasets reveal the effectiveness of the proposed framework and validate its suitability for fire detection in closed-circuit television surveillance systems compared to state-of-the-art methods.