The Edikan Mine,which consists of Fobinso and Esuajah gold deposits,lies within the Asankrangwa Gold Belt of the Birimian Supergroup in the Kumasi Basin.The metasedimentary rocks in the Basins and the faulted metavolc...The Edikan Mine,which consists of Fobinso and Esuajah gold deposits,lies within the Asankrangwa Gold Belt of the Birimian Supergroup in the Kumasi Basin.The metasedimentary rocks in the Basins and the faulted metavolcanic rocks in the Belts that make up the Birimian Supergroup were intruded by granitoids during the Eburnean Orogeny.This research aims to classify granitoids in the Edikan Mine and ascertain the petrogenetic and geochemical characteristics of some auriferous granitoids in the wider Kumasi Basin,Ghana,to understand the implications for geodynamic settings.A multi-methods approach involving field studies,petrographic studies,and whole-rock geochemical analysis was used to achieve the goal of the study.Petrographic studies revealed a relatively high abundance of plagioclase and a low percentage of K-feldspars(anorthoclase and orthoclase)in the Fobinso samples,suggesting that the samples are granodioritic in nature,while the Esuajah samples showed relatively low plagioclase abundance and a high percentage in K-feldspars,indicating that they are granitic.The granitoids from the study areas are co-magmatic.The granitoids in Esuajah and Fobinso are generally enriched in large ion lithophile elements and light rare earth elements than high field strength elements,middle rare earth elements,and heavy rare earth elements,indicating mixing with crustal sources during the evolution of the granitoids.The granitoids were tectonically formed in a syn-collisional+VAG setting,which implies that they were formed in the subduction zone setting.Fobinso granodiorites showed S-type signatures with evidence of extensive crustal contamination,while the Esuajah granites showed I-type signatures with little or no crustal contamination and are peraluminous.Gold mineralization in the study area is structurally and lithologically controlled with shear zones,faulting,and veining as the principal structures controlling the mineralization.The late-stage vein,V3,in the Edikan Mine is characterized by a low vein angle and is mineralized.展开更多
Exosomes derived from bone mesenchymal stem cells(BMSCs)show promising potential for treating bone defects.However,their clinical application is hindered by low yield and insufficient repair ability.Three-dimensional(...Exosomes derived from bone mesenchymal stem cells(BMSCs)show promising potential for treating bone defects.However,their clinical application is hindered by low yield and insufficient repair ability.Three-dimensional(3D)mechanical stimulation has been a well-known method for enhancing exosome secretion;however,the traditional stimulation process is always achieved by controlling the displacement of manipulators,which may induce uneven loading distribution and degradation of stimulation strength.Here,we propose a micro-stretching manipulator that automatically controls the stretching force applied to gelatin methacryloyl(GelMA)/hyaluronic acid methacryloyl(HAMA)hybrid hydrogel sheets containing BMSCs within an incubator.To ensure the structural stability of the sheets after long-term stretching,the mixing ratio between GelMA and HAMA was optimized according to the mechanical property response of the sheets to cyclical loading.Subsequently,force-controlled mechanical loading was applied to the BMSC-laden sheets to produce exosomes.Compared with displacement control,force-controlled loading provides a more stable force stimulation,thereby enhancing exosome secretion.Furthermore,continuously stimulated exosomes exhibited a stronger capacity for promoting osteogenic differentiation of BMSCs and facilitating the repair of bone defects in a rat model.These findings suggest that force-controlled loading of cell-laden hydrogels offers a novel approach for the production of BMSC-derived exosomes and their application in bone repair.展开更多
In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to ...In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.展开更多
In this paper,we define for the trace operator,the solution of certain models of vibrating plates standards with initial data in a strategic region spaces of weak regularities.Indeed,we know that the notion of regiona...In this paper,we define for the trace operator,the solution of certain models of vibrating plates standards with initial data in a strategic region spaces of weak regularities.Indeed,we know that the notion of regional controllability is more adapted to systems described by dynamic systems.Regional controllability results in a strategic area were established for vibrating plates by the Hilbertian Uniqueness Method.展开更多
This paper presents a summary of some recent experimental and industrial case studies of active disturbance rejection control （ADRC）. ADRC is a novel disturbance estimation and rejection concept, leading to a new te...This paper presents a summary of some recent experimental and industrial case studies of active disturbance rejection control （ADRC）. ADRC is a novel disturbance estimation and rejection concept, leading to a new technology with a distinct advantage where, unlike most existing methods, disturbances, internal and external, are actively estimated and rejected. Applications of the new approach in solving industry-wide bench mark problems have led to a slew of innovative solutions. The scope of the applications shown in this paper includes motion control, robotic-enhanced limb rehabilitation trainings, fuel cell systems, and the two-mass-spring benchmark problem. Recent production line validation results obtained are also included.展开更多
The focus of drug delivery is shifting toward smart drug carriers that release the cargo in response to a change in the microenvironment due to an internal or external trigger. As the most clinically successful nanosy...The focus of drug delivery is shifting toward smart drug carriers that release the cargo in response to a change in the microenvironment due to an internal or external trigger. As the most clinically successful nanosystem, liposomes naturally come under the spotlight of this trend. This review summarizes the latest development about the design and construction of photo-responsive liposomes with gold nanoparticles for the controlled drug release. Alongside, we overview the mechanism involved in this process and the representative applications.展开更多
In recent decades,studies on delayed system dynamics have attracted increasing attention and advances have been achieved in stability,nonlinearity,delay identification, delay elimination and application.However,most o...In recent decades,studies on delayed system dynamics have attracted increasing attention and advances have been achieved in stability,nonlinearity,delay identification, delay elimination and application.However,most of the existing work is on the theoretical basis and little is on the experiment.This paper presents our experimental studies on delayed feedback control conducted in recent years with the focus on the discussion of a DSP-based delayed experiment system.Some phenomena in our delay experiments are discussed and a few topics of interest for further research are brought forward.展开更多
We use two appropriate bounded invertible operators to define a controlled frame with optimal frame bounds. We characterize those operators that produces Parseval controlled frames also we state a way to construct nea...We use two appropriate bounded invertible operators to define a controlled frame with optimal frame bounds. We characterize those operators that produces Parseval controlled frames also we state a way to construct nearly Parseval controlled frames. We intro- duce a new perturbation of controlled frames to obtain new frames from a given one. Also we reduce the distance of frames by appropriate operators and produce nearly dual frames from two given frames which are not dual frames for each other.展开更多
Conventional sliding mode controllers are based on the assumption of switching control, but a well-known drawback of such controllers is the chattering phenomenon. To overcome the undesirable chattering effects, the d...Conventional sliding mode controllers are based on the assumption of switching control, but a well-known drawback of such controllers is the chattering phenomenon. To overcome the undesirable chattering effects, the discontinuity in the control law can be smoothed out in a thin boundary layer neighboring the switching surface. In this paper, rigorous proofs of the boundedness and convergence properties of smooth sliding mode controllers are presented. This result corrects flawed conclusions previously reached in the literature. An illustrative example is also presented in order to confirm the convergence of the tracking error vector to the defined bounded region.展开更多
Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-siz...Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-sized crystal particles of magnetic iron minerals,which are only synthesized in lowoxygen environments.Although the mechanism of aerobic repression for magnetosome biomineralization has not yet fully understood,a series of studies have verified that redox modulation is pivotal for magnetosome formation.In this review,these advances in redox modulation for magnetosome biosynthesis are highlighted,mainly including respiration pathway enzymes,specific magnetosome-associated redox proteins,and oxygen-or nitrate-sensing regulators.Furthermore,their relationship during magnetosome biomineralization is discussed to give insight into redox control and biomineralization and inspire potential solutions for the application of respiration pathways to improve the yields of magnetosome.展开更多
Some new criteria for the chaotic lag synchronization are proposed. At first,lag synchronization scheme for identical master-slave Lur‘ e systems by replacing variables control and the relevant error system are given...Some new criteria for the chaotic lag synchronization are proposed. At first,lag synchronization scheme for identical master-slave Lur‘ e systems by replacing variables control and the relevant error system are given, and the relations between absolute stability of the error system and the chaotic lag synchronization are described. Then, based on a quadratic Lyapunov function, two new Lur‘ e criteria for the above chaotic lag synchronization are proved. Four corresponding frequency domain criteria are further derived by means of Meyer-Kalman-Yacubovia Lemma. These frequency domain criteria are applied to analyze the lag synchronization of general master-slave Chua's circuits so that some ranges of the parameters in which the master-slave Chua's circuits achieve chaotic lag synchronization by replacing single-variable control are attained. Finally, some examples are given to verify the theoretical results.展开更多
Active control of wall his is important in both application and basic researches. In order to establish a solid background for the expected application,it is necessary to perform detailed studies on the base nows,on t...Active control of wall his is important in both application and basic researches. In order to establish a solid background for the expected application,it is necessary to perform detailed studies on the base nows,on their stability characteristics and on the identification technique of coherent structures. This paper is a summarizing article rather than a detailed technical report, Its main purpose is just to introduce the recent progress in the related area.展开更多
Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-bas...Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-based residual generator in its core gives a more general form of the previous works.Its applications to residual centred modelling of uncertain control systems,fault detection in feedback control systems with uncertainties,fault-tolerant control(FTC)as well as control performance degradation monitoring,detection and recovery are introduced.In conclusion,some future perspectives are proposed.展开更多
The paper addresses the adaptive behaviour of parallel fuzzy proportional plus fuzzy integral plus fuzzy derivative (FP+FI+FD) controller. The parallel FP+FI+FD controller is actually a non-linear adaptive controller ...The paper addresses the adaptive behaviour of parallel fuzzy proportional plus fuzzy integral plus fuzzy derivative (FP+FI+FD) controller. The parallel FP+FI+FD controller is actually a non-linear adaptive controller whose gain changes continuously with output of the process under control. Two non-stationary processes, whose characteristics change with time, are considered for simulation study. Simulation is performed using software LabVIEW TM . The set-point tracking response of parallel FP+FI+FD is compared with conventional parallel proportional plus integral plus derivative (PID) controller, tuned with the Ziegler-Nichols (Z-N) tuning technique. Simulation results show that conventional PID controller fails to track the set-point and becomes unstable as the process changes its characteristic with time. But the parallel FP+FI+FD controller shows considerably much better set-point tracking response and does not deviate from steady state. Also, a huge spike is observed in the output of PID controller as the reference set-point and process parameters are changed, while the FP+FI+FD controller gives spike free control signal.展开更多
Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these...Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface electromyography.In this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord injury.Eleven patients with chronic complete thoracic spinal cord injury were recruited.Surface electromyography data from eight major leg muscles were acquired and compared before and after the passive activity protocol.The results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of activation.Although the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically significant.These findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.展开更多
Several phytoecdysteroids have been found in the extracts of A. multiflora and A.linearifolia using HPLC analysis. Those were 20-OH ecdysone, cyasterone, 3-acetate-20-OH ecdysone, 2-acetate-20-OH ecdysone, qugalactone...Several phytoecdysteroids have been found in the extracts of A. multiflora and A.linearifolia using HPLC analysis. Those were 20-OH ecdysone, cyasterone, 3-acetate-20-OH ecdysone, 2-acetate-20-OH ecdysone, qugalactone. We found out that those phytoecdysteroids could lead the second instar larva of Clostera anastomosis and Stipnotia candida to death. The modified mortality rate was from 44.64% to 96.24%. Those extracts could signiticantly reduce the amount of nymph produced by the female Tuberolachnus salignus, The number of the nymph produced after treating with those extracts was only 20% to 70% of that produced by the untreated group. The death rate of the newly produced nymph which treated was among 33.33% to 58.82%. It was much higher than the death rate of the control group (1l7.57%).展开更多
The new energy power generation is becoming increasingly important in the power system.Such as photovoltaic power generation has become a research hotspot,however,due to the characteristics of light radiation changes,...The new energy power generation is becoming increasingly important in the power system.Such as photovoltaic power generation has become a research hotspot,however,due to the characteristics of light radiation changes,photovoltaic power generation is unstable and random,resulting in a low utilization rate and directly affecting the stability of the power grid.To solve this problem,this paper proposes a coordinated control strategy for a newenergy power generation system with a hybrid energy storage unit based on the lithium iron phosphate-supercapacitor hybrid energy storage unit.Firstly,the variational mode decomposition algorithm is used to separate the high and low frequencies of the power signal,which is conducive to the rapid and accurate suppression of the power fluctuation of the energy storage system.Secondly,the fuzzy control algorithm is introduced to balance the power between energy storage.In this paper,the actual data is used for simulation,and the simulation results show that the strategy realizes the effective suppression of the bus voltage fluctuation and the accurate control of the internal state of the energy storage unit,effectively avoiding problems such as overshoot and over-discharge,and can significantly improve the stability of the photovoltaic power generation systemand the stability of the Direct Current bus.It is of great significance to promote the development of collaborative control technology for photovoltaic hybrid energy storage units.展开更多
Issues related to the implementation of dynamic programming for optimal control of a three-dimensional dynamic model (the fish populations management problem) are presented. They belong to a class of models called Lot...Issues related to the implementation of dynamic programming for optimal control of a three-dimensional dynamic model (the fish populations management problem) are presented. They belong to a class of models called Lotka-Volterra models. The existence of bionomic equilibria will be considered. The problem of optimal harvest policy is then solved for the control of various classes of its behaviour. Therefore the focus will be the optimality conditions by using the Bellman principle. Moreover, we consider a different form for the optimal value of the control vector, namely the feedback or closed-loop form of the control. Academic examples are studied in order to demonstrate the proposed methods.展开更多
In this paper two classes of equivalence transform methods for solving ordinary differential equations are proposed. One class of method is the equivalence integral transform method for special differential algebraic ...In this paper two classes of equivalence transform methods for solving ordinary differential equations are proposed. One class of method is the equivalence integral transform method for special differential algebraic problems. The advantage of this class of method is such that the amount of work calculating one integration with parameters becomes that of two interpolations, when the system of nonlinear equations is solved on the right hand side function. The other class of method is the equivalence substitution method for avoiding calculating derivative on the right hand side function. In order to avoid calculation derivatives, two equivalence substitution methods are proposed here. The application instances of some special effect of the equivalence substitution methods are given.展开更多
文摘The Edikan Mine,which consists of Fobinso and Esuajah gold deposits,lies within the Asankrangwa Gold Belt of the Birimian Supergroup in the Kumasi Basin.The metasedimentary rocks in the Basins and the faulted metavolcanic rocks in the Belts that make up the Birimian Supergroup were intruded by granitoids during the Eburnean Orogeny.This research aims to classify granitoids in the Edikan Mine and ascertain the petrogenetic and geochemical characteristics of some auriferous granitoids in the wider Kumasi Basin,Ghana,to understand the implications for geodynamic settings.A multi-methods approach involving field studies,petrographic studies,and whole-rock geochemical analysis was used to achieve the goal of the study.Petrographic studies revealed a relatively high abundance of plagioclase and a low percentage of K-feldspars(anorthoclase and orthoclase)in the Fobinso samples,suggesting that the samples are granodioritic in nature,while the Esuajah samples showed relatively low plagioclase abundance and a high percentage in K-feldspars,indicating that they are granitic.The granitoids from the study areas are co-magmatic.The granitoids in Esuajah and Fobinso are generally enriched in large ion lithophile elements and light rare earth elements than high field strength elements,middle rare earth elements,and heavy rare earth elements,indicating mixing with crustal sources during the evolution of the granitoids.The granitoids were tectonically formed in a syn-collisional+VAG setting,which implies that they were formed in the subduction zone setting.Fobinso granodiorites showed S-type signatures with evidence of extensive crustal contamination,while the Esuajah granites showed I-type signatures with little or no crustal contamination and are peraluminous.Gold mineralization in the study area is structurally and lithologically controlled with shear zones,faulting,and veining as the principal structures controlling the mineralization.The late-stage vein,V3,in the Edikan Mine is characterized by a low vein angle and is mineralized.
基金support from the National Key Research and Development Program of China(No.2021YFB3802105-3)the National Natural Science Foundation of China(No.62173043).
文摘Exosomes derived from bone mesenchymal stem cells(BMSCs)show promising potential for treating bone defects.However,their clinical application is hindered by low yield and insufficient repair ability.Three-dimensional(3D)mechanical stimulation has been a well-known method for enhancing exosome secretion;however,the traditional stimulation process is always achieved by controlling the displacement of manipulators,which may induce uneven loading distribution and degradation of stimulation strength.Here,we propose a micro-stretching manipulator that automatically controls the stretching force applied to gelatin methacryloyl(GelMA)/hyaluronic acid methacryloyl(HAMA)hybrid hydrogel sheets containing BMSCs within an incubator.To ensure the structural stability of the sheets after long-term stretching,the mixing ratio between GelMA and HAMA was optimized according to the mechanical property response of the sheets to cyclical loading.Subsequently,force-controlled mechanical loading was applied to the BMSC-laden sheets to produce exosomes.Compared with displacement control,force-controlled loading provides a more stable force stimulation,thereby enhancing exosome secretion.Furthermore,continuously stimulated exosomes exhibited a stronger capacity for promoting osteogenic differentiation of BMSCs and facilitating the repair of bone defects in a rat model.These findings suggest that force-controlled loading of cell-laden hydrogels offers a novel approach for the production of BMSC-derived exosomes and their application in bone repair.
基金Supported in part by Natural Science Foundation of Guangxi(2023GXNSFAA026246)in part by the Central Government's Guide to Local Science and Technology Development Fund(GuikeZY23055044)in part by the National Natural Science Foundation of China(62363003)。
文摘In this paper,we consider the maximal positive definite solution of the nonlinear matrix equation.By using the idea of Algorithm 2.1 in ZHANG(2013),a new inversion-free method with a stepsize parameter is proposed to obtain the maximal positive definite solution of nonlinear matrix equation X+A^(*)X|^(-α)A=Q with the case 0<α≤1.Based on this method,a new iterative algorithm is developed,and its convergence proof is given.Finally,two numerical examples are provided to show the effectiveness of the proposed method.
文摘In this paper,we define for the trace operator,the solution of certain models of vibrating plates standards with initial data in a strategic region spaces of weak regularities.Indeed,we know that the notion of regional controllability is more adapted to systems described by dynamic systems.Regional controllability results in a strategic area were established for vibrating plates by the Hilbertian Uniqueness Method.
文摘This paper presents a summary of some recent experimental and industrial case studies of active disturbance rejection control （ADRC）. ADRC is a novel disturbance estimation and rejection concept, leading to a new technology with a distinct advantage where, unlike most existing methods, disturbances, internal and external, are actively estimated and rejected. Applications of the new approach in solving industry-wide bench mark problems have led to a slew of innovative solutions. The scope of the applications shown in this paper includes motion control, robotic-enhanced limb rehabilitation trainings, fuel cell systems, and the two-mass-spring benchmark problem. Recent production line validation results obtained are also included.
文摘The focus of drug delivery is shifting toward smart drug carriers that release the cargo in response to a change in the microenvironment due to an internal or external trigger. As the most clinically successful nanosystem, liposomes naturally come under the spotlight of this trend. This review summarizes the latest development about the design and construction of photo-responsive liposomes with gold nanoparticles for the controlled drug release. Alongside, we overview the mechanism involved in this process and the representative applications.
基金supported by the Science Foundation of China (11072146,11002087,10772112)the Key Scientific Project of Shanghai Municipal Education Commission(09ZZ17)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China (20070248032)the Research Project of State Key Laboratory of Ocean Engineering of China(GKZD010807).
文摘In recent decades,studies on delayed system dynamics have attracted increasing attention and advances have been achieved in stability,nonlinearity,delay identification, delay elimination and application.However,most of the existing work is on the theoretical basis and little is on the experiment.This paper presents our experimental studies on delayed feedback control conducted in recent years with the focus on the discussion of a DSP-based delayed experiment system.Some phenomena in our delay experiments are discussed and a few topics of interest for further research are brought forward.
文摘We use two appropriate bounded invertible operators to define a controlled frame with optimal frame bounds. We characterize those operators that produces Parseval controlled frames also we state a way to construct nearly Parseval controlled frames. We intro- duce a new perturbation of controlled frames to obtain new frames from a given one. Also we reduce the distance of frames by appropriate operators and produce nearly dual frames from two given frames which are not dual frames for each other.
基金supported by FAPERJ–State of Rio de JaneiroResearch Foundation (No. E-26/170.086/2006)
文摘Conventional sliding mode controllers are based on the assumption of switching control, but a well-known drawback of such controllers is the chattering phenomenon. To overcome the undesirable chattering effects, the discontinuity in the control law can be smoothed out in a thin boundary layer neighboring the switching surface. In this paper, rigorous proofs of the boundedness and convergence properties of smooth sliding mode controllers are presented. This result corrects flawed conclusions previously reached in the literature. An illustrative example is also presented in order to confirm the convergence of the tracking error vector to the defined bounded region.
基金Supported by the National Natural Science Foundation of China(No.41706165)the Fundamental Research Funds of Shandong University(No.2019HW022)。
文摘Magnetotactic bacteria can orientate in the Earth’s magnetic field to search for their preferred microoxic environments,which is achieved by their unique organelles,the magnetosomes.Magnetosomes contain nanometer-sized crystal particles of magnetic iron minerals,which are only synthesized in lowoxygen environments.Although the mechanism of aerobic repression for magnetosome biomineralization has not yet fully understood,a series of studies have verified that redox modulation is pivotal for magnetosome formation.In this review,these advances in redox modulation for magnetosome biosynthesis are highlighted,mainly including respiration pathway enzymes,specific magnetosome-associated redox proteins,and oxygen-or nitrate-sensing regulators.Furthermore,their relationship during magnetosome biomineralization is discussed to give insight into redox control and biomineralization and inspire potential solutions for the application of respiration pathways to improve the yields of magnetosome.
基金This work was supported by the National Natural Science Foundation of China (No. 10371136)the Natural Science Foundation of Guangdong Province of China (No.021765).
文摘Some new criteria for the chaotic lag synchronization are proposed. At first,lag synchronization scheme for identical master-slave Lur‘ e systems by replacing variables control and the relevant error system are given, and the relations between absolute stability of the error system and the chaotic lag synchronization are described. Then, based on a quadratic Lyapunov function, two new Lur‘ e criteria for the above chaotic lag synchronization are proved. Four corresponding frequency domain criteria are further derived by means of Meyer-Kalman-Yacubovia Lemma. These frequency domain criteria are applied to analyze the lag synchronization of general master-slave Chua's circuits so that some ranges of the parameters in which the master-slave Chua's circuits achieve chaotic lag synchronization by replacing single-variable control are attained. Finally, some examples are given to verify the theoretical results.
基金supported by the National Natural Science Foundation of China(No.11372210 and No.51405343)the Research Fund for the Doctoral Program of Higher Education of China(No.20120032110010)Tianjin Research Program of Application Foundation and Advanced Technology(No.12JCZDJC28000 and No.15JCQNJC05000)
文摘Active control of wall his is important in both application and basic researches. In order to establish a solid background for the expected application,it is necessary to perform detailed studies on the base nows,on their stability characteristics and on the identification technique of coherent structures. This paper is a summarizing article rather than a detailed technical report, Its main purpose is just to introduce the recent progress in the related area.
基金This work was supported by the National Natural Science Foundation of China(62020106003,62073029)the Beijing Natural Science Foundation(4202045)the Fundamental Research Funds for the Central Universities(FRF-TP-20-012A3).
文摘Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-based residual generator in its core gives a more general form of the previous works.Its applications to residual centred modelling of uncertain control systems,fault detection in feedback control systems with uncertainties,fault-tolerant control(FTC)as well as control performance degradation monitoring,detection and recovery are introduced.In conclusion,some future perspectives are proposed.
文摘The paper addresses the adaptive behaviour of parallel fuzzy proportional plus fuzzy integral plus fuzzy derivative (FP+FI+FD) controller. The parallel FP+FI+FD controller is actually a non-linear adaptive controller whose gain changes continuously with output of the process under control. Two non-stationary processes, whose characteristics change with time, are considered for simulation study. Simulation is performed using software LabVIEW TM . The set-point tracking response of parallel FP+FI+FD is compared with conventional parallel proportional plus integral plus derivative (PID) controller, tuned with the Ziegler-Nichols (Z-N) tuning technique. Simulation results show that conventional PID controller fails to track the set-point and becomes unstable as the process changes its characteristic with time. But the parallel FP+FI+FD controller shows considerably much better set-point tracking response and does not deviate from steady state. Also, a huge spike is observed in the output of PID controller as the reference set-point and process parameters are changed, while the FP+FI+FD controller gives spike free control signal.
基金supported by the Fundamental Research Funds for Central Public Welfare Research Institute,No.2020CZ-5(to WS and GS)the National Natural Science Foundation of China,No.31970970(to JSR)Fundamental Research Funds for the Central Universities,No.YWF-23-YG-QB-010(to JSR)。
文摘Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury level.However,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface electromyography.In this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord injury.Eleven patients with chronic complete thoracic spinal cord injury were recruited.Surface electromyography data from eight major leg muscles were acquired and compared before and after the passive activity protocol.The results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of activation.Although the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically significant.These findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.
文摘Several phytoecdysteroids have been found in the extracts of A. multiflora and A.linearifolia using HPLC analysis. Those were 20-OH ecdysone, cyasterone, 3-acetate-20-OH ecdysone, 2-acetate-20-OH ecdysone, qugalactone. We found out that those phytoecdysteroids could lead the second instar larva of Clostera anastomosis and Stipnotia candida to death. The modified mortality rate was from 44.64% to 96.24%. Those extracts could signiticantly reduce the amount of nymph produced by the female Tuberolachnus salignus, The number of the nymph produced after treating with those extracts was only 20% to 70% of that produced by the untreated group. The death rate of the newly produced nymph which treated was among 33.33% to 58.82%. It was much higher than the death rate of the control group (1l7.57%).
基金supported by the State Grid Corporation of China Science and Technology Project,grant number 52270723000900K.
文摘The new energy power generation is becoming increasingly important in the power system.Such as photovoltaic power generation has become a research hotspot,however,due to the characteristics of light radiation changes,photovoltaic power generation is unstable and random,resulting in a low utilization rate and directly affecting the stability of the power grid.To solve this problem,this paper proposes a coordinated control strategy for a newenergy power generation system with a hybrid energy storage unit based on the lithium iron phosphate-supercapacitor hybrid energy storage unit.Firstly,the variational mode decomposition algorithm is used to separate the high and low frequencies of the power signal,which is conducive to the rapid and accurate suppression of the power fluctuation of the energy storage system.Secondly,the fuzzy control algorithm is introduced to balance the power between energy storage.In this paper,the actual data is used for simulation,and the simulation results show that the strategy realizes the effective suppression of the bus voltage fluctuation and the accurate control of the internal state of the energy storage unit,effectively avoiding problems such as overshoot and over-discharge,and can significantly improve the stability of the photovoltaic power generation systemand the stability of the Direct Current bus.It is of great significance to promote the development of collaborative control technology for photovoltaic hybrid energy storage units.
文摘Issues related to the implementation of dynamic programming for optimal control of a three-dimensional dynamic model (the fish populations management problem) are presented. They belong to a class of models called Lotka-Volterra models. The existence of bionomic equilibria will be considered. The problem of optimal harvest policy is then solved for the control of various classes of its behaviour. Therefore the focus will be the optimality conditions by using the Bellman principle. Moreover, we consider a different form for the optimal value of the control vector, namely the feedback or closed-loop form of the control. Academic examples are studied in order to demonstrate the proposed methods.
基金The project was supported by the National Natural Science Faundation of China
文摘In this paper two classes of equivalence transform methods for solving ordinary differential equations are proposed. One class of method is the equivalence integral transform method for special differential algebraic problems. The advantage of this class of method is such that the amount of work calculating one integration with parameters becomes that of two interpolations, when the system of nonlinear equations is solved on the right hand side function. The other class of method is the equivalence substitution method for avoiding calculating derivative on the right hand side function. In order to avoid calculation derivatives, two equivalence substitution methods are proposed here. The application instances of some special effect of the equivalence substitution methods are given.
