The effect of polyacrylic acid(PAA)on the corrosion behavior of Alloy 690 in simulated pressurized water reactor secondary water was investigated.The duplex oxide film structure,consisting of a Ni-rich outer layer and...The effect of polyacrylic acid(PAA)on the corrosion behavior of Alloy 690 in simulated pressurized water reactor secondary water was investigated.The duplex oxide film structure,consisting of a Ni-rich outer layer and a Cr-rich inner layer,was maintained regardless of PAA presence.PAA inhibited the growth of outer Ni-rich particles while promoting Cr enrichment in the inner layer and inducing its amorphization,both enhancing oxidation resistance.However,excess PAA(≥500 ppb)suppressed protective oxide formation during initial oxidation,leading to oxygen penetration into the matrix.A PAA concentration of around 250 ppb is considered optimal for steam generators,as it provides the benefits of PAA without adverse effects on the alloy.展开更多
Transition metal selenides are considered promising electrochemical energy storage materials due to their excellent rate properties and high capacity based on multi-step conversion reactions.However,its practical appl...Transition metal selenides are considered promising electrochemical energy storage materials due to their excellent rate properties and high capacity based on multi-step conversion reactions.However,its practical applications are hampered by poor conductivity and large volume variation for Na^(+)storage,which resulting fast capacity decay.Herein,a facile metal-organic framework(MOF)derived method is explored to embed Cu_(2-x)Se@C particles into a carbon nanobelts matrix.Such carbon encapsulated nanobelts'structural moderate integral electronic conductivity and maintained the structure from collapsing during Na^(+)insertion/extraction.Furthermore,the porous structure of these nanobelts endows enough void space to mitigate volume stress and provide more diffusion channels for Na^(+)/electrons transporting.Due to the unique structure,these Cu_(2-x)Se@C nanobelts achieved ultra-stable cycling performance(170.7 m Ah/g at1.0 A/g after 1000 cycles)and superior rate capability(94.6 m Ah/g at 8 A/g)for sodium-ion batteries.The kinetic analysis reveals that these Cu_(2-x)Se@C nanobelts with considerable pesoudecapactive contribution benefit the rapid sodiation/desodiation.This rational design strategy broadens an avenue for the development of metal selenide materials for energy storage devices.展开更多
A new kind of secure communication system which combines the chaotic encryption means with the conventional encryption method is discussed. With the analysis results and the experiment data, the anti-attack ability of...A new kind of secure communication system which combines the chaotic encryption means with the conventional encryption method is discussed. With the analysis results and the experiment data, the anti-attack ability of this communication system is significantly improved compared to that of the either method. At the same time, a new method of chaotic synchronization is proposed. With a small mixed discrete chaotic signal, it is quickly to synchronize the communication and a good security performance is ensured.展开更多
The research of cluster supply chains is a new direction and a hotspot of the industrial cluster theory. On the condition of the coordination game, the enterprises may be stuck on the non-efficient equilibrium status,...The research of cluster supply chains is a new direction and a hotspot of the industrial cluster theory. On the condition of the coordination game, the enterprises may be stuck on the non-efficient equilibrium status, which becomes an important problem that must be considered on cluster supply chains. A symmetrical coordination game model is constituted to describe the competition and cooperation relationship of the same-quality manufacturers on cluster supply chains. The methods of the non-cooperation game theory and the evolutionary game theory are respectively used to analyze the model, whose parameters＇ influences under each method are then compared. It can be concluded that the analysis of the evolutionary game theory is more realistic and practical. Finally, three approaches are considered to break away from being path-dependence locked-in non-efficient status during this coordination game evolutionary process, which provide the development of cluster supply chains with an effective forecasting and Pareto optimizing method.展开更多
Chaos-based encryption schemes have been studied extensively, while the security analysis methods for them are still problems to be resolved. Based on the periodic orbit theory, this paper proposes a novel security an...Chaos-based encryption schemes have been studied extensively, while the security analysis methods for them are still problems to be resolved. Based on the periodic orbit theory, this paper proposes a novel security analysis method. The periodic orbits theory indicates that the fundamental frequency of the spiraling orbits is the natural frequency of associated linearized system, which is decided by the parameters of the chaotic system. Thus, it is possible to recover the plaintext of secure communication systems based on chaotic shift keying by getting the average time on the spiraling orbits. Analysis and simulation results show that the security analysis method can break chaos shift keying secure communication systems, which use the parameters as keys.展开更多
This paper deals with the nonlinear effect of the drift motion of multi-chain mooring buoys. The buoy's motion in time domain is determined for the case that the wave and mooring force are nonlinear. The Kotorayam...This paper deals with the nonlinear effect of the drift motion of multi-chain mooring buoys. The buoy's motion in time domain is determined for the case that the wave and mooring force are nonlinear. The Kotorayama's method of hydrodynamic effect in a single mooring chain is expanded to multi-mooring chains. The time history of drift motion of the mooring buoy in regular waves and wave groups is calculated. The relation between the drift motion and the wave height or difference frequency is discussed. It can be shown that the effect of the hydrodynamic force acting on the mooring chain has remarkable influence on the total drift motion of the mooring buoy. In a wave group, its amplitude is mainly controled by the wave height and has little relation with difference frequency.展开更多
It is known that centers,widths,and weights are three mainly considered factors in constructing a radial basis function(RBF)network.This paper aims at constructing a compact RBF network with two main steps.In the firs...It is known that centers,widths,and weights are three mainly considered factors in constructing a radial basis function(RBF)network.This paper aims at constructing a compact RBF network with two main steps.In the first step,the coarse clusters computed from triangle inequalities are refined to obtain the locations of centers by the defined maximum degree spanning tree(MDST).Meanwhile the coarse widths are obtained.In the second step,a learning algorithm referred to as anisotropic gradient descent method is presented to further refine the above coarse widths.Experiments of the proposed algorithm show its great performance in times series prediction and classification.展开更多
The global asymptotical stability for a class of stochastic delayed neural networks （SDNNs） with Maxkovian jumping parameters is considered. By applying Lyapunov functional method and Ito＇s differential rule, new d...The global asymptotical stability for a class of stochastic delayed neural networks （SDNNs） with Maxkovian jumping parameters is considered. By applying Lyapunov functional method and Ito＇s differential rule, new delay-dependent stability conditions are derived. All results are expressed in terms of linear matrix inequality （LMI）, and a numerical example is presented to illustrate the correctness and less conservativeness of the proposed method.展开更多
Decentralized robust stabilization problem of discrete-time fuzzy large-scale systems with parametric uncertainties is considered. This uncertain fuzzy large-scale system consists of N interconnected T-S fuzzy subsyst...Decentralized robust stabilization problem of discrete-time fuzzy large-scale systems with parametric uncertainties is considered. This uncertain fuzzy large-scale system consists of N interconnected T-S fuzzy subsystems, and the parametric uncertainties are unknown but norm-bounded. Based on Lyapunov stability theory and decentralized control theory of large-scale system, the design schema of decentralized parallel distributed compensation （DPDC） fuzzy controllers to ensure the asymptotic stability of the whole fuzzy large-scale system is proposed. The existence conditions for these controllers take the forms of LMIs. Finally a numerical simulation example is given to show the utility of the method proposed.展开更多
Simulation of a class of delay stochastic system with distributed parameter is discussed. Difference schemes for the numerical computation of delay stochastic system are obtained. The precision of the difference schem...Simulation of a class of delay stochastic system with distributed parameter is discussed. Difference schemes for the numerical computation of delay stochastic system are obtained. The precision of the difference scheme and the efficiency of the difference scheme in simulation of delay stochastic system with distributed parameter are analyzed. Examples are given to illustrate the application of the method.展开更多
In this paper, the matrix algebraic equations involved in the optimal control problem of time-invariant linear Ito stochastic systems, named Riccati- Ito equations in the paper, are investigated. The necessary and suf...In this paper, the matrix algebraic equations involved in the optimal control problem of time-invariant linear Ito stochastic systems, named Riccati- Ito equations in the paper, are investigated. The necessary and sufficient condition for the existence of positive definite solutions of the Riccati- Ito equations is obtained and an iterative solution to the Riccati- Ito equations is also given in the paper thus a complete solution to the basic problem of optimal control of time-invariant linear Ito stochastic systems is then obtained. An example is given at the end of the paper to illustrate the application of the result of the paper.展开更多
Based on the actual experience of cooperation in the supply chain, the Nash solution of two enterprises cooperative games is given. Not only is the solution unique, but it is also stable, and neither side has the capa...Based on the actual experience of cooperation in the supply chain, the Nash solution of two enterprises cooperative games is given. Not only is the solution unique, but it is also stable, and neither side has the capability to deviate the allocation of interests from the equilibrium point. If some firm tries to withdraw from cooperation or threaten to use other particular strategy, the negotiations are likely to achieve the distribution by the threat game; The calculating method of the choice of the optimal bargaining base point and the corresponding optimal pay-off vector are given.展开更多
An increasing demand for high data rate transmission and protection over bandlimited channels with severe inter-symbol interference has resulted in a flurry of activity to improve channel equalization, In conjunction ...An increasing demand for high data rate transmission and protection over bandlimited channels with severe inter-symbol interference has resulted in a flurry of activity to improve channel equalization, In conjunction with equalization, channel coding-decoding can be employed to improve system performance. In this letter, the performance of the three stage turbo-equalization-decoding employing log maximum a posteriori probability is experimentally evaluated by a fading simulator. The BER is evaluated using various information sequence and interleaver sizes taking into account that the communication medium is a noisy inter symbol interference channel.展开更多
The present research is an experimental study on heat transfer characteristics of a natural circulation cooling system for electronic components. A smooth chip and two micro-pin-finned chips were tested. The chip is m...The present research is an experimental study on heat transfer characteristics of a natural circulation cooling system for electronic components. A smooth chip and two micro-pin-finned chips were tested. The chip is mounted on the base of a rectangular horizontal duct located at the bottom of 250 mm high natural circulation loop.FC-72 is used as a coolant. The test conditions are set that the operation pressure of experimental system is 1. 013× 105 Pa, the flow rate of FC-72 is 150 g/min and the subcoolings are 10 K, 25 K and 35 k, respectively. Effect of the subcooling on nucleate boiling and critical heat flux(CHF) were investigated. The results show that subcoolingis found to significantly affect CHF for all chips and micro-pin-finned chips sharply enhanced the boiling heat transfer, CHF of micro-pin-finned chips are 2.5～3 times as large as that of smooth chip at the same subcooling.展开更多
After reviewing current researches on early warning,it is found that“bad”data of some systems is not easy to obtain,which makes methods proposed by these researches unsuitable for monitored systems.An interactive ea...After reviewing current researches on early warning,it is found that“bad”data of some systems is not easy to obtain,which makes methods proposed by these researches unsuitable for monitored systems.An interactive early warning technique based on SVDD(support vector data description)is proposed to adopt“good”data as samples to overcome the difficulty in obtaining the“bad”data.The process consists of two parts:(1)A hypersphere is fitted on“good”data using SVDD.If the data object are outside the hypersphere,it would be taken as“suspicious”;(2)A group of experts would decide whether the suspicious data is“bad”or“good”,early warning messages would be issued according to the decisions.And the detailed process of implementation is proposed.At last,an experiment based on data of a macroeconomic system is conducted to verify the proposed technique.展开更多
A new algorithm is proposed for joint diagonalization. With a modified objective function, the new algorithm not only excludes trivial and unbalanced solutions successfully, but is also easily optimized. In addition, ...A new algorithm is proposed for joint diagonalization. With a modified objective function, the new algorithm not only excludes trivial and unbalanced solutions successfully, but is also easily optimized. In addition, with the new objective function, the proposed algorithm can work well in online blind source separation （BSS） for the first time, although this family of algorithms is always thought to be valid only in batch-mode BSS by far. Simulations show that it is a very competitive joint diagonalization algorithm.展开更多
基金supported by the LingChuang Re-search Project of China National Nuclear Corporation。
文摘The effect of polyacrylic acid(PAA)on the corrosion behavior of Alloy 690 in simulated pressurized water reactor secondary water was investigated.The duplex oxide film structure,consisting of a Ni-rich outer layer and a Cr-rich inner layer,was maintained regardless of PAA presence.PAA inhibited the growth of outer Ni-rich particles while promoting Cr enrichment in the inner layer and inducing its amorphization,both enhancing oxidation resistance.However,excess PAA(≥500 ppb)suppressed protective oxide formation during initial oxidation,leading to oxygen penetration into the matrix.A PAA concentration of around 250 ppb is considered optimal for steam generators,as it provides the benefits of PAA without adverse effects on the alloy.
基金supported by the National Key Research and Development Program of China(No.2022YFB2502000)the National Natural Science Foundation of China(Nos.U21A2033251771076,52301266,42203047)+2 种基金R&D Program in Key Areas of Guangdong Province(No.2020B0101030005)Science and Technology Planning Project of Guangzhou(No.2024A04J9999)GDUT Large-Scale Instruments Open Foundation(No.ATC2022201)。
文摘Transition metal selenides are considered promising electrochemical energy storage materials due to their excellent rate properties and high capacity based on multi-step conversion reactions.However,its practical applications are hampered by poor conductivity and large volume variation for Na^(+)storage,which resulting fast capacity decay.Herein,a facile metal-organic framework(MOF)derived method is explored to embed Cu_(2-x)Se@C particles into a carbon nanobelts matrix.Such carbon encapsulated nanobelts'structural moderate integral electronic conductivity and maintained the structure from collapsing during Na^(+)insertion/extraction.Furthermore,the porous structure of these nanobelts endows enough void space to mitigate volume stress and provide more diffusion channels for Na^(+)/electrons transporting.Due to the unique structure,these Cu_(2-x)Se@C nanobelts achieved ultra-stable cycling performance(170.7 m Ah/g at1.0 A/g after 1000 cycles)and superior rate capability(94.6 m Ah/g at 8 A/g)for sodium-ion batteries.The kinetic analysis reveals that these Cu_(2-x)Se@C nanobelts with considerable pesoudecapactive contribution benefit the rapid sodiation/desodiation.This rational design strategy broadens an avenue for the development of metal selenide materials for energy storage devices.
文摘A new kind of secure communication system which combines the chaotic encryption means with the conventional encryption method is discussed. With the analysis results and the experiment data, the anti-attack ability of this communication system is significantly improved compared to that of the either method. At the same time, a new method of chaotic synchronization is proposed. With a small mixed discrete chaotic signal, it is quickly to synchronize the communication and a good security performance is ensured.
基金the National Natural Science Foundation of China (60374023)the Natural ScienceFoundation of Guangdong Province (011629).
文摘The research of cluster supply chains is a new direction and a hotspot of the industrial cluster theory. On the condition of the coordination game, the enterprises may be stuck on the non-efficient equilibrium status, which becomes an important problem that must be considered on cluster supply chains. A symmetrical coordination game model is constituted to describe the competition and cooperation relationship of the same-quality manufacturers on cluster supply chains. The methods of the non-cooperation game theory and the evolutionary game theory are respectively used to analyze the model, whose parameters＇ influences under each method are then compared. It can be concluded that the analysis of the evolutionary game theory is more realistic and practical. Finally, three approaches are considered to break away from being path-dependence locked-in non-efficient status during this coordination game evolutionary process, which provide the development of cluster supply chains with an effective forecasting and Pareto optimizing method.
文摘Chaos-based encryption schemes have been studied extensively, while the security analysis methods for them are still problems to be resolved. Based on the periodic orbit theory, this paper proposes a novel security analysis method. The periodic orbits theory indicates that the fundamental frequency of the spiraling orbits is the natural frequency of associated linearized system, which is decided by the parameters of the chaotic system. Thus, it is possible to recover the plaintext of secure communication systems based on chaotic shift keying by getting the average time on the spiraling orbits. Analysis and simulation results show that the security analysis method can break chaos shift keying secure communication systems, which use the parameters as keys.
文摘This paper deals with the nonlinear effect of the drift motion of multi-chain mooring buoys. The buoy's motion in time domain is determined for the case that the wave and mooring force are nonlinear. The Kotorayama's method of hydrodynamic effect in a single mooring chain is expanded to multi-mooring chains. The time history of drift motion of the mooring buoy in regular waves and wave groups is calculated. The relation between the drift motion and the wave height or difference frequency is discussed. It can be shown that the effect of the hydrodynamic force acting on the mooring chain has remarkable influence on the total drift motion of the mooring buoy. In a wave group, its amplitude is mainly controled by the wave height and has little relation with difference frequency.
基金supported by Key Program of National Natural Science Foundation of China(U0635001)China Postdoctoral Science Foundation(20060390728)the Natural Science Fund of Guangdong Province,China(07006490)
文摘It is known that centers,widths,and weights are three mainly considered factors in constructing a radial basis function(RBF)network.This paper aims at constructing a compact RBF network with two main steps.In the first step,the coarse clusters computed from triangle inequalities are refined to obtain the locations of centers by the defined maximum degree spanning tree(MDST).Meanwhile the coarse widths are obtained.In the second step,a learning algorithm referred to as anisotropic gradient descent method is presented to further refine the above coarse widths.Experiments of the proposed algorithm show its great performance in times series prediction and classification.
基金supported by the National Natural Science Foundation of China(60874114).
文摘The global asymptotical stability for a class of stochastic delayed neural networks （SDNNs） with Maxkovian jumping parameters is considered. By applying Lyapunov functional method and Ito＇s differential rule, new delay-dependent stability conditions are derived. All results are expressed in terms of linear matrix inequality （LMI）, and a numerical example is presented to illustrate the correctness and less conservativeness of the proposed method.
基金This project was supported by NSFC Project (60474047), (60334010) and GuangDong Province Natural Science Foundationof China(31406)and China Postdoctoral Science Foundation (20060390725).
文摘Decentralized robust stabilization problem of discrete-time fuzzy large-scale systems with parametric uncertainties is considered. This uncertain fuzzy large-scale system consists of N interconnected T-S fuzzy subsystems, and the parametric uncertainties are unknown but norm-bounded. Based on Lyapunov stability theory and decentralized control theory of large-scale system, the design schema of decentralized parallel distributed compensation （DPDC） fuzzy controllers to ensure the asymptotic stability of the whole fuzzy large-scale system is proposed. The existence conditions for these controllers take the forms of LMIs. Finally a numerical simulation example is given to show the utility of the method proposed.
文摘Simulation of a class of delay stochastic system with distributed parameter is discussed. Difference schemes for the numerical computation of delay stochastic system are obtained. The precision of the difference scheme and the efficiency of the difference scheme in simulation of delay stochastic system with distributed parameter are analyzed. Examples are given to illustrate the application of the method.
文摘In this paper, the matrix algebraic equations involved in the optimal control problem of time-invariant linear Ito stochastic systems, named Riccati- Ito equations in the paper, are investigated. The necessary and sufficient condition for the existence of positive definite solutions of the Riccati- Ito equations is obtained and an iterative solution to the Riccati- Ito equations is also given in the paper thus a complete solution to the basic problem of optimal control of time-invariant linear Ito stochastic systems is then obtained. An example is given at the end of the paper to illustrate the application of the result of the paper.
文摘Based on the actual experience of cooperation in the supply chain, the Nash solution of two enterprises cooperative games is given. Not only is the solution unique, but it is also stable, and neither side has the capability to deviate the allocation of interests from the equilibrium point. If some firm tries to withdraw from cooperation or threaten to use other particular strategy, the negotiations are likely to achieve the distribution by the threat game; The calculating method of the choice of the optimal bargaining base point and the corresponding optimal pay-off vector are given.
基金the National Natural Science Foundation of China(No.60172048)
文摘An increasing demand for high data rate transmission and protection over bandlimited channels with severe inter-symbol interference has resulted in a flurry of activity to improve channel equalization, In conjunction with equalization, channel coding-decoding can be employed to improve system performance. In this letter, the performance of the three stage turbo-equalization-decoding employing log maximum a posteriori probability is experimentally evaluated by a fading simulator. The BER is evaluated using various information sequence and interleaver sizes taking into account that the communication medium is a noisy inter symbol interference channel.
文摘The present research is an experimental study on heat transfer characteristics of a natural circulation cooling system for electronic components. A smooth chip and two micro-pin-finned chips were tested. The chip is mounted on the base of a rectangular horizontal duct located at the bottom of 250 mm high natural circulation loop.FC-72 is used as a coolant. The test conditions are set that the operation pressure of experimental system is 1. 013× 105 Pa, the flow rate of FC-72 is 150 g/min and the subcoolings are 10 K, 25 K and 35 k, respectively. Effect of the subcooling on nucleate boiling and critical heat flux(CHF) were investigated. The results show that subcoolingis found to significantly affect CHF for all chips and micro-pin-finned chips sharply enhanced the boiling heat transfer, CHF of micro-pin-finned chips are 2.5～3 times as large as that of smooth chip at the same subcooling.
基金the National Natural Science Foundation of China(70471074)Department of Science and Technology of Guangdong Province(2004B36001051).
文摘After reviewing current researches on early warning,it is found that“bad”data of some systems is not easy to obtain,which makes methods proposed by these researches unsuitable for monitored systems.An interactive early warning technique based on SVDD(support vector data description)is proposed to adopt“good”data as samples to overcome the difficulty in obtaining the“bad”data.The process consists of two parts:(1)A hypersphere is fitted on“good”data using SVDD.If the data object are outside the hypersphere,it would be taken as“suspicious”;(2)A group of experts would decide whether the suspicious data is“bad”or“good”,early warning messages would be issued according to the decisions.And the detailed process of implementation is proposed.At last,an experiment based on data of a macroeconomic system is conducted to verify the proposed technique.
基金supported partly by the Key Program of National Natural Science Foundation of China (U0635001U0835003)+3 种基金the National Natural Science Foundation of China (60505005 60674033 60774094)the Natural Science Fundof Guangdong Province (05006508).
文摘A new algorithm is proposed for joint diagonalization. With a modified objective function, the new algorithm not only excludes trivial and unbalanced solutions successfully, but is also easily optimized. In addition, with the new objective function, the proposed algorithm can work well in online blind source separation （BSS） for the first time, although this family of algorithms is always thought to be valid only in batch-mode BSS by far. Simulations show that it is a very competitive joint diagonalization algorithm.
