The DLE (dry low emission) technology has already been used on industrial gas turbine combustor and the NO X emission can be limited to 25 ppmv (@15% O 2 ), but one of the destructive effects is combustion instability...The DLE (dry low emission) technology has already been used on industrial gas turbine combustor and the NO X emission can be limited to 25 ppmv (@15% O 2 ), but one of the destructive effects is combustion instability. In this paper, the dynamic and emission characteristics of a DLE gas turbine combustor have been researched in the authors' laboratory, and the results show that the key source of combustion instability is the non-uniformity of fuel in the flame zone. Two main fuel supply methods have been used to form different fuel distribution types; it is shown that in the perfectly premixed case the emission level is low and combustion process is stable. The PPF also has an obvious effect on the combustor's emission and dynamic characteristics.展开更多
Estimation of the lateral stability region and torque distribution on steering is very important to improve stability in lateral handling for all wheel drive electric vehicles.Based on the built-nonlinear vehicle dyna...Estimation of the lateral stability region and torque distribution on steering is very important to improve stability in lateral handling for all wheel drive electric vehicles.Based on the built-nonlinear vehicle dynamic model,the lateral stability region of the vehicle related to steering is estimated using Lyapunov function.We obtained stable equilibrium points of non-straight driving according to the estimated lateral stability region and also reconstructed the Lyapunov function matrix,which proved that the closed-loop system composed of yaw rate and lateral velocity is satisfied with negative definite property.In addition,the designed controller dynamically allocates the drive torque in terms of the vertical load and slip rate of the four wheels.The simulation results show that the estimated lateral stability region and the designed controller are satisfactory in handling stability performance against different roads and vehicle parameters.展开更多
A three-state protocol for the SARG04 decoy-state quantum key distribution(QKD)based on an unstable source is presented. The lower bound to the secure key generation rate is derived without using the basic hypothesis ...A three-state protocol for the SARG04 decoy-state quantum key distribution(QKD)based on an unstable source is presented. The lower bound to the secure key generation rate is derived without using the basic hypothesis of the original decoy-state idea.The three-state SARG04 decoy-state protocol with an unstable parametric down-conversion source is considered in the simulation.The simulation results show that the protocol in this paper with an unstable source gives a key generation rate that is close to that with a stable source,and only slight advantage appears by using a stable source when the transmission distance is long.So the SARG04 decoy-state protocol with an unstable source still can obtain the unconditional security with a slightly shortened final key.展开更多
The emergence of any new infectious disease poses much stress on the government to control the spread of such disease. The easy, fast and less expensive way to slow down the spread of disease is to make the population...The emergence of any new infectious disease poses much stress on the government to control the spread of such disease. The easy, fast and less expensive way to slow down the spread of disease is to make the population be aware of its spread and possible control mechanisms. For this purpose, government allocates some funds to make public aware through mass media, print media, pamphlets, etc. Keeping this in view, in this paper, a nonlinear mathematical model is proposed and analyzed to assess the effect of time delay in providing funds by the government to warn people. It is assumed that suscep- tible individuals contract infection through the direct contact with infected individuals; however the rate of contracting infection is a decreasing function of funds availability. The proposed model is analyzed using stability theory of delay differential equations and numerical simulations. The model analysis shows that the increase in funds to warn people reduces the number of infected individuals but delay in providing the funds desta- bilizes the interior equilibrium and may cause stability switches.展开更多
We have made an extensive numerical study of a modified model proposed by Olami,Feder,and Christensen to describe earthquake behavior.Two situations were considered in this paper.One situation is that the energy of th...We have made an extensive numerical study of a modified model proposed by Olami,Feder,and Christensen to describe earthquake behavior.Two situations were considered in this paper.One situation is that the energy of the unstable site is redistributed to its nearest neighbors randomly not averagely and keeps itself to zero.The other situation is that the energy of the unstable site is redistributed to its nearest neighbors randomly and keeps some energy for itself instead of reset to zero.Different boundary conditions were considered as well.By analyzing the distribution of earthquake sizes,we found that self-organized criticality can be excited only in the conservative case or the approximate conservative case in the above situations.Some evidence indicated that the critical exponent of both above situations and the original OFC model tend to the same result in the conservative case.The only difference is that the avalanche size in the original model is bigger.This result may be closer to the real world,after all,every crust plate size is different.展开更多
The paper presents a model of a redundant robot configuration with a built-in safety. By the method of strong continuous semi-group, the paper analyzes the essential spectrum of the system operator before and after pe...The paper presents a model of a redundant robot configuration with a built-in safety. By the method of strong continuous semi-group, the paper analyzes the essential spectrum of the system operator before and after perturbation. The results show that in s special condition, the dynamic solution of the system is exponential stability and tends to the steady solution of the system.展开更多
基金supported by the National Natural Science Foundation of China(No.50976116and No.50806077)
文摘The DLE (dry low emission) technology has already been used on industrial gas turbine combustor and the NO X emission can be limited to 25 ppmv (@15% O 2 ), but one of the destructive effects is combustion instability. In this paper, the dynamic and emission characteristics of a DLE gas turbine combustor have been researched in the authors' laboratory, and the results show that the key source of combustion instability is the non-uniformity of fuel in the flame zone. Two main fuel supply methods have been used to form different fuel distribution types; it is shown that in the perfectly premixed case the emission level is low and combustion process is stable. The PPF also has an obvious effect on the combustor's emission and dynamic characteristics.
基金The National Natural Science Foundation of China(Grant No.51105074)The Foundation of State Key Laboratory of Automotive Safety and Energy,Tsinghua University(Grant No.KF14192)The Fundamental Research Funds for the Central Universities and Jiangsu Province Postgraduate Scientific Research and Innovation Plan Projects(Grant No.KYLX_0103)
文摘Estimation of the lateral stability region and torque distribution on steering is very important to improve stability in lateral handling for all wheel drive electric vehicles.Based on the built-nonlinear vehicle dynamic model,the lateral stability region of the vehicle related to steering is estimated using Lyapunov function.We obtained stable equilibrium points of non-straight driving according to the estimated lateral stability region and also reconstructed the Lyapunov function matrix,which proved that the closed-loop system composed of yaw rate and lateral velocity is satisfied with negative definite property.In addition,the designed controller dynamically allocates the drive torque in terms of the vertical load and slip rate of the four wheels.The simulation results show that the estimated lateral stability region and the designed controller are satisfactory in handling stability performance against different roads and vehicle parameters.
基金supported by the National High Technology Research and Development Program of China(No.2009AAJ128)
文摘A three-state protocol for the SARG04 decoy-state quantum key distribution(QKD)based on an unstable source is presented. The lower bound to the secure key generation rate is derived without using the basic hypothesis of the original decoy-state idea.The three-state SARG04 decoy-state protocol with an unstable parametric down-conversion source is considered in the simulation.The simulation results show that the protocol in this paper with an unstable source gives a key generation rate that is close to that with a stable source,and only slight advantage appears by using a stable source when the transmission distance is long.So the SARG04 decoy-state protocol with an unstable source still can obtain the unconditional security with a slightly shortened final key.
文摘The emergence of any new infectious disease poses much stress on the government to control the spread of such disease. The easy, fast and less expensive way to slow down the spread of disease is to make the population be aware of its spread and possible control mechanisms. For this purpose, government allocates some funds to make public aware through mass media, print media, pamphlets, etc. Keeping this in view, in this paper, a nonlinear mathematical model is proposed and analyzed to assess the effect of time delay in providing funds by the government to warn people. It is assumed that suscep- tible individuals contract infection through the direct contact with infected individuals; however the rate of contracting infection is a decreasing function of funds availability. The proposed model is analyzed using stability theory of delay differential equations and numerical simulations. The model analysis shows that the increase in funds to warn people reduces the number of infected individuals but delay in providing the funds desta- bilizes the interior equilibrium and may cause stability switches.
基金Supported by National Natural Science Foundation of China under Grant Nos.11675096 and 11305098the Fundamental Research Funds for the Central Universities under Grant No.GK201702001+1 种基金FPALAB-SNNU under Grant No.16QNGG007Interdisciplinary Incubation Project of SNU under Grant No.5
文摘We have made an extensive numerical study of a modified model proposed by Olami,Feder,and Christensen to describe earthquake behavior.Two situations were considered in this paper.One situation is that the energy of the unstable site is redistributed to its nearest neighbors randomly not averagely and keeps itself to zero.The other situation is that the energy of the unstable site is redistributed to its nearest neighbors randomly and keeps some energy for itself instead of reset to zero.Different boundary conditions were considered as well.By analyzing the distribution of earthquake sizes,we found that self-organized criticality can be excited only in the conservative case or the approximate conservative case in the above situations.Some evidence indicated that the critical exponent of both above situations and the original OFC model tend to the same result in the conservative case.The only difference is that the avalanche size in the original model is bigger.This result may be closer to the real world,after all,every crust plate size is different.
文摘The paper presents a model of a redundant robot configuration with a built-in safety. By the method of strong continuous semi-group, the paper analyzes the essential spectrum of the system operator before and after perturbation. The results show that in s special condition, the dynamic solution of the system is exponential stability and tends to the steady solution of the system.
