Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the ...Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the operating costs of the power system.This paper proposes a two-stage planning method for distributed generation and energy storage systems that considers the hierarchical partitioning of source-storage-load.Firstly,an electrical distance structural index that comprehensively considers active power output and reactive power output is proposed to divide the distributed generation voltage regulation domain and determine the access location and number of distributed power sources.Secondly,a two-stage planning is carried out based on the zoning results.In the phase 1 distribution network-zoning optimization layer,the network loss is minimized so that the node voltage in the area does not exceed the limit,and the distributed generation configuration results are initially determined;in phase 2,the partition-node optimization layer is planned with the goal of economic optimization,and the distance-based improved ant lion algorithm is used to solve the problem to obtain the optimal distributed generation and energy storage systemconfiguration.Finally,the IEEE33 node systemwas used for simulation.The results showed that the voltage quality was significantly improved after optimization,and the overall revenue increased by about 20.6%,verifying the effectiveness of the two-stage planning.展开更多
In this paper the definitions of generalized transfer functios of control system and itscontinuity are presented.Using generalized transfer function as a tool,a set of theorems fordeciding movement stability have been...In this paper the definitions of generalized transfer functios of control system and itscontinuity are presented.Using generalized transfer function as a tool,a set of theorems fordeciding movement stability have been constructed.Thus basing understanding of thecharacteristics of a control dynamics system on its measured procedure will simplify thedecision method of movement stability problems.展开更多
Recent progress in plasma control studies on the improvement of plasma performance in Heliotron J is reviewed. The supersonic molecular beam injection (SMBI) fueling is successfully applied to Heliotron J plasma. A ...Recent progress in plasma control studies on the improvement of plasma performance in Heliotron J is reviewed. The supersonic molecular beam injection (SMBI) fueling is successfully applied to Heliotron J plasma. A supersonic H2-beam is effectively injected to increase fueling efficiency and generate a peaked density profile. Local fueling with a short-pulsed SMBI can increase the core plasma density and avoid the degradation arising from edge cooling. Second harmonic electron cyclotron current drive (ECCD) experiments were conducted by launching a focused Gaussian beam with a parallel refractive index of -0.05 ≤ Nil 〈 0.6. Results show that the electron cyclotron (EC) driven current is determined not only by Nil but also by local magnetic field (B) structure where the EC power is deposited. Detailed analysis of the observed NI and B dependences is in progress with a ray-tracing simulation using the TRAVIS code. Fast ion velocity distribution was investigated using fast protons generated by ion cyclotron resonant frequency (ICRF) minority heating. For the standard configuration in Heliotron J, charge ex- change neutral particle analysis (CX-NPA) measurements show higher effective temperature of fast minority protons in the on-axis resonance case compared to that in the HFS (high field side) off-axis resonance case. However, the increase in bulk ion temperature in the HFS resonance case is larger than that in the on-axis resonance.展开更多
Big data is playing an important role in preventing,control and monitoring COVID-19,but during the process,the legality of the use of personal information shall be paid attention to.Personal information should be divi...Big data is playing an important role in preventing,control and monitoring COVID-19,but during the process,the legality of the use of personal information shall be paid attention to.Personal information should be divided into general information and sensitive information,and the use of sensitive information should take"Consent"as its legality basis.In the process of personal information collection,the subject qualification of the collection organization or personnel should be clearly defined,and the starting conditions and process specifications of the collection work should be determined.The use of personal information should be in accordance with legal provisions or agreed ways and purposes and should not violate individual privacy rights and other personality rights,and should not improperly display the"digital image"of individuals.展开更多
Legal audit is a statutory control of the accounts carried out based on internal control(IC).Meanwhile,paradoxically,IC is not always transparent to the legal auditor,but rather a compromise to his expectations.What a...Legal audit is a statutory control of the accounts carried out based on internal control(IC).Meanwhile,paradoxically,IC is not always transparent to the legal auditor,but rather a compromise to his expectations.What are the determinants that allow the auditor to adapt to it?This paper proposes the analysis of issues and determinants of the effectiveness of legal audit in the context of an opaque IC.This study is carried out on a sample of 56 limited liability companies in Cameroon,carefully selected based on the existence of an IC service.The determinants explaining the auditor’s effectiveness in his mission are noted.展开更多
In this paper,an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load a...In this paper,an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load and PV power variations in a stand-alone DC microgrid.The strategy includes primary and secondary control.Among them,the primary control suppresses the DC microgrid voltage fluctuation through the I and II section control,and the secondary control aims to correct the P-U curve of the energy storage system and the PV system,thus reducing the steady-state bus voltage excursion.The simulation results demonstrate that the proposed control strategy effectively achieves SOC balancing and enhances the immunity of bus voltage.The proposed strategy improves the voltage fluctuation suppression ability by approximately 39.4%and 43.1%under the PV power and load power fluctuation conditions,respectively.Furthermore,the steady-state deviation of the bus voltage,△U_(dc) is only 0.01–0.1 V,ensuring stable operation of the DC microgrid in fluctuating power environments.展开更多
Objective:To explore the effect of the Plan-Do-Check-Action(PDCA)cycle on hand hygiene and nosocomial infection quality of or thopedic medical staff.Methods:The whole year of 2021 was selected to monitor the quality o...Objective:To explore the effect of the Plan-Do-Check-Action(PDCA)cycle on hand hygiene and nosocomial infection quality of or thopedic medical staff.Methods:The whole year of 2021 was selected to monitor the quality of hand hygiene and hospitalization.Follow-up monitoring and real-time recording during the period of morning shift and medical operation concentration time,and compare the compliance of hand hygiene before and after implementation,and evaluate the quality of nosocomial infection.Results:The hand hygiene compliance of doctors and nurses in stage P was 82%.The compliance of medical staff in stage D was 93%.The compliance of stage C was 94%and that of stage A was 95%.The quality score of hospital self-examination nosocomial infection was also significantly increased.Conclusions:The PDCA management cycle can effectively improve the compliance of hand hygiene and the nosocomial infection quality,which is wor thy of circulatory application in or thopedic nosocomial infection quality control,especially improving the quality of hand hygiene.展开更多
Three recent breakthroughs due to AI in arts and science serve as motivation:An award winning digital image,protein folding,fast matrix multiplication.Many recent developments in artificial neural networks,particularl...Three recent breakthroughs due to AI in arts and science serve as motivation:An award winning digital image,protein folding,fast matrix multiplication.Many recent developments in artificial neural networks,particularly deep learning(DL),applied and relevant to computational mechanics(solid,fluids,finite-element technology)are reviewed in detail.Both hybrid and pure machine learning(ML)methods are discussed.Hybrid methods combine traditional PDE discretizations with ML methods either(1)to help model complex nonlinear constitutive relations,(2)to nonlinearly reduce the model order for efficient simulation(turbulence),or(3)to accelerate the simulation by predicting certain components in the traditional integration methods.Here,methods(1)and(2)relied on Long-Short-Term Memory(LSTM)architecture,with method(3)relying on convolutional neural networks.Pure ML methods to solve(nonlinear)PDEs are represented by Physics-Informed Neural network(PINN)methods,which could be combined with attention mechanism to address discontinuous solutions.Both LSTM and attention architectures,together with modern and generalized classic optimizers to include stochasticity for DL networks,are extensively reviewed.Kernel machines,including Gaussian processes,are provided to sufficient depth for more advanced works such as shallow networks with infinite width.Not only addressing experts,readers are assumed familiar with computational mechanics,but not with DL,whose concepts and applications are built up from the basics,aiming at bringing first-time learners quickly to the forefront of research.History and limitations of AI are recounted and discussed,with particular attention at pointing out misstatements or misconceptions of the classics,even in well-known references.Positioning and pointing control of a large-deformable beam is given as an example.展开更多
PEM (Proton Exchange Membrane) fuel cell is a promising renewable energy source to a wide range of applications for its clean products and high power density. However, controlling its humidity is a challenging probl...PEM (Proton Exchange Membrane) fuel cell is a promising renewable energy source to a wide range of applications for its clean products and high power density. However, controlling its humidity is a challenging problem due to the interdependence of several phenomena contributing in membrane's water content. This work deals with efficiency improvement of PEM fuel cells via humidity control. An innovative strategy of control based on the model of Ref. [1] is proposed. It consists on regulating gas humidification rates according to the power demand so that to minimize power losses. The proposed control takes into consideration constraints related to humidification in order to avoid dry out or flooding of the membrane. Simulations results show that time-phasing between hydrogen and oxygen humidification rates plays an important role in minimizing power losses. The proposed control shows significant improvement in the fuel cell's efficiency up to 20%.展开更多
Yield improvement and advanced defect control can be identified as the driving forces for modeling of industrial bulk crystal growth. Yield improvement is mainly achieved by upscaling of the whole crystal growth appar...Yield improvement and advanced defect control can be identified as the driving forces for modeling of industrial bulk crystal growth. Yield improvement is mainly achieved by upscaling of the whole crystal growth apparatus and increased processing windows with more tolerances for parameter variations. Advanced defect control means on one hand a reduction of the number of deficient crystal defects and on the other hand the formation of beneficial crystal defects with a uniform distribution and well defined concentrations in the whole crystal. This "defect engineering" relates to the whole crystal growth process as well as the following cooling and optional annealing processes, respectively. These topics were illustrated in the paper by examples of modeling and experimental results of bulk growth of silicon (Si), gallium arsenide (GaAs), indium phosphide (InP) and calcium fluoride (CaF2). These examples also involve the state of the art of modeling of the most important melt growth techniques, crystal pulling (Czochralski methods) and vertical gradient freeze (Bridgman-type methods).展开更多
The fluctuation of active power output of wind farm has many negative impacts on large-scale wind power integration into power grid. In this paper, flywheel energy storage system (FESS) was connected to AC side of the...The fluctuation of active power output of wind farm has many negative impacts on large-scale wind power integration into power grid. In this paper, flywheel energy storage system (FESS) was connected to AC side of the doubly-fed induction generator (DFIG) wind farm to realize smooth control of wind power output. Based on improved wind power prediction algorithm and wind speed-power curve modeling, a new smooth control strategy with the FESS was proposed. The requirement of power system dispatch for wind power prediction and flywheel rotor speed limit were taken into consideration during the process. While smoothing the wind power fluctuation, FESS can track short-term planned output of wind farm. It was demonstrated by quantitative analysis of simulation results that the proposed control strategy can smooth the active power fluctuation of wind farm effectively and thereby improve power quality of the power grid.展开更多
Aiming at the problem of network-induced delay and data dropout in networked control system, an improved fuzzy controller is proposed in this paper. Considering the great influence of a controller on the performance o...Aiming at the problem of network-induced delay and data dropout in networked control system, an improved fuzzy controller is proposed in this paper. Considering the great influence of a controller on the performance of control system, an improved controller with a second order fuzzy controller and network-induced delay compensator being added to the basic fuzzy controller is proposed to realize self-regulation on-line. For this type of controller, neither plant model nor measurement of network delay is required. So it is capable of automatically adjusting quantified factor, pro- portional factor, and integral factor according to the control system error and its derivative. The design makes full use of the advantages of quickness in operation and reduction of steady state error because of its integral function. The con- troller has a good control effect on time-delay and can keep a better performance by self-regulation on-line in the net- work with data dropout and interference. It is good in quickness, adaptability, and robustness, which is favorable for controlling the long time-delay system.展开更多
This paper illustrates the benefits of a multivariable linearizing control approach applied to an industrial crystallization process. This relevant approach is declined according to two different strategies: first, a ...This paper illustrates the benefits of a multivariable linearizing control approach applied to an industrial crystallization process. This relevant approach is declined according to two different strategies: first, a setpoint tracking is proposed for the couple crystal mass/concentration, whereas a second way consists in tracking of crystal content and concentration. The controlled variables, unavailable online, are issued from an observer developed in previous works. The performance of these strategies, which application to cane sugar crystallization constitutes a real novelty, are compared with experimental data issued from a PID-controlled industrial plant. The results reveal a significant improvement of energy efficiency, leading to an economy of more than 10% of energy.展开更多
The variable air volume(VAV)air conditioning system is with strong coupling and large time delay,for which model predictive control(MPC)is normally used to pursue performance improvement.Aiming at the difficulty of th...The variable air volume(VAV)air conditioning system is with strong coupling and large time delay,for which model predictive control(MPC)is normally used to pursue performance improvement.Aiming at the difficulty of the parameter selection of VAV MPC controller which is difficult to make the system have a desired response,a novel tuning method based on machine learning and improved particle swarm optimization(PSO)is proposed.In this method,the relationship between MPC controller parameters and time domain performance indices is established via machine learning.Then the PSO is used to optimize MPC controller parameters to get better performance in terms of time domain indices.In addition,the PSO algorithm is further modified under the principle of population attenuation and event triggering to tune parameters of MPC and reduce the computation time of tuning method.Finally,the effectiveness of the proposed method is validated via a hardware-in-the-loop VAV system.展开更多
The aim of the study was to verify the efficacy of the Tone-Control method in inducing a reduction in the tension of the muscles of the shoulder girdle,and therefore a normalisation of posture in the segment.The autho...The aim of the study was to verify the efficacy of the Tone-Control method in inducing a reduction in the tension of the muscles of the shoulder girdle,and therefore a normalisation of posture in the segment.The authors analysed the change in posture,which was related to the muscle tension of the pectoralis major muscle and the trapezius muscle,resulting from the administration of a programme of encoded exercises known as the Tone Control method.The study was conducted on 70 patients with postural back pain,aged between 25 and 81 years and with a mean age of 61.9 years,11 male patients and 59 female patients,who attended group rehabilitation for a minimum of 10 and a maximum of 15 sessions.Acute phase patients,patients on anti-inflammatory pharmacological treatment and patients with hernias or bulging causing thecal sac impingement were excluded from the study.Measurements were taken of the angles of the joints in the scapulohumeral segment during the first and last sessions.The NRS(numeric rating scale)pain scale was administered at the start and end of the cycle of sessions.Conclusions:Patients in the study group experienced improvements in the angle measurements that were proportionally greater than those of the control group,together with a considerable reduction in perceived pain,with an overall improvement in posture and shoulder girdle function.展开更多
In the context of the information age, with the causes of the financial deregulation of the bank in the financial industry competition intensifies, the communication of science and technology advancement, there are in...In the context of the information age, with the causes of the financial deregulation of the bank in the financial industry competition intensifies, the communication of science and technology advancement, there are innovative financial instruments to achieve orgasm. With that, comes the increased risk of commercial banks. China' s banking innovation started late, but rapidly develops. More seriously, in the development of the innovation process, there is not enough emphasis on the legal risk, which causes great risks.展开更多
The corruption problem of China's rural cadres has exposed the weakness of the absence of legal control in rural administration. In the face of the problems in the legal control of corruption in rural cadres,it is...The corruption problem of China's rural cadres has exposed the weakness of the absence of legal control in rural administration. In the face of the problems in the legal control of corruption in rural cadres,it is required to improve the laws and regulations,strengthen law enforcement,and strengthen the supervision and guidance of higher-level party committee and governments to bring the corruption of rural cadres into the rule of law.展开更多
Feeding habit which is regulated by many factors including the intrinsic and external factors, such as appetite, structure of the digestive tract and feed palatability, is an important content in the study of genetic ...Feeding habit which is regulated by many factors including the intrinsic and external factors, such as appetite, structure of the digestive tract and feed palatability, is an important content in the study of genetic improvement. The genetic regulation is one of the major parts among the researches. This research reported the progress of the polymorphism of genes associated with appetite and its correla- tion with feeding habits, and summarized the studies on improvements of fish feed- ing and protein sources of the artificial feeding in order to provide theoretic basis for cultivating the improved varieties in feeding habit.展开更多
In this paper, the fixed-time event-triggered obstacle avoidance consensus control for a multi-AUV time-varying formation system in a 3D environment is presented by using an improved artificial potential field and lea...In this paper, the fixed-time event-triggered obstacle avoidance consensus control for a multi-AUV time-varying formation system in a 3D environment is presented by using an improved artificial potential field and leader-follower strategy(IAPF-LF). Firstly, the proposed fixed-time control can achieve the desired multi-AUV formation within a fixed settling time in any initial system state. Secondly, an event-triggered communication strategy is developed to govern the communication among AUVs, and the communication energy consumption can be decremented. The time-varying formation obstacle avoidance control algorithm based on IAPF-LF is designed to avoid static and dynamic obstacles, the desired formation is maintained in the presence of external disturbances, and there is no Zeno behavior under the fixed-time event-triggered consensus control strategy.The stability of the system is proved by the Lyapunov function and inequality scaling. Finally, simulation examples and water pool experiments are reported to verify the performance of the proposed theoretical algorithms.展开更多
基金supported by North China Electric Power Research Institute’s Self-Funded Science and Technology Project“Research on Distributed Energy Storage Optimal Configuration and Operation Control Technology for Photovoltaic Promotion in the Entire County”(KJZ2022049).
文摘Aiming at the consumption problems caused by the high proportion of renewable energy being connected to the distribution network,it also aims to improve the power supply reliability of the power system and reduce the operating costs of the power system.This paper proposes a two-stage planning method for distributed generation and energy storage systems that considers the hierarchical partitioning of source-storage-load.Firstly,an electrical distance structural index that comprehensively considers active power output and reactive power output is proposed to divide the distributed generation voltage regulation domain and determine the access location and number of distributed power sources.Secondly,a two-stage planning is carried out based on the zoning results.In the phase 1 distribution network-zoning optimization layer,the network loss is minimized so that the node voltage in the area does not exceed the limit,and the distributed generation configuration results are initially determined;in phase 2,the partition-node optimization layer is planned with the goal of economic optimization,and the distance-based improved ant lion algorithm is used to solve the problem to obtain the optimal distributed generation and energy storage systemconfiguration.Finally,the IEEE33 node systemwas used for simulation.The results showed that the voltage quality was significantly improved after optimization,and the overall revenue increased by about 20.6%,verifying the effectiveness of the two-stage planning.
文摘In this paper the definitions of generalized transfer functios of control system and itscontinuity are presented.Using generalized transfer function as a tool,a set of theorems fordeciding movement stability have been constructed.Thus basing understanding of thecharacteristics of a control dynamics system on its measured procedure will simplify thedecision method of movement stability problems.
基金supported by the JSPS-CAS Core University Program in the field of "'Plasma and Nuclear Fusion"the Collaboration Program of the Laboratory for Complex Energy Processes. IAE. Kyoto University. the NIFS Collaborative flesearch Program (NIFS10KUHL030. etc.)+1 种基金the NIFS/NINS project of Formation of International Network for Scientific Collaborationsthe Grant-in-Aid for Sci.Research. MEXT
文摘Recent progress in plasma control studies on the improvement of plasma performance in Heliotron J is reviewed. The supersonic molecular beam injection (SMBI) fueling is successfully applied to Heliotron J plasma. A supersonic H2-beam is effectively injected to increase fueling efficiency and generate a peaked density profile. Local fueling with a short-pulsed SMBI can increase the core plasma density and avoid the degradation arising from edge cooling. Second harmonic electron cyclotron current drive (ECCD) experiments were conducted by launching a focused Gaussian beam with a parallel refractive index of -0.05 ≤ Nil 〈 0.6. Results show that the electron cyclotron (EC) driven current is determined not only by Nil but also by local magnetic field (B) structure where the EC power is deposited. Detailed analysis of the observed NI and B dependences is in progress with a ray-tracing simulation using the TRAVIS code. Fast ion velocity distribution was investigated using fast protons generated by ion cyclotron resonant frequency (ICRF) minority heating. For the standard configuration in Heliotron J, charge ex- change neutral particle analysis (CX-NPA) measurements show higher effective temperature of fast minority protons in the on-axis resonance case compared to that in the HFS (high field side) off-axis resonance case. However, the increase in bulk ion temperature in the HFS resonance case is larger than that in the on-axis resonance.
文摘Big data is playing an important role in preventing,control and monitoring COVID-19,but during the process,the legality of the use of personal information shall be paid attention to.Personal information should be divided into general information and sensitive information,and the use of sensitive information should take"Consent"as its legality basis.In the process of personal information collection,the subject qualification of the collection organization or personnel should be clearly defined,and the starting conditions and process specifications of the collection work should be determined.The use of personal information should be in accordance with legal provisions or agreed ways and purposes and should not violate individual privacy rights and other personality rights,and should not improperly display the"digital image"of individuals.
文摘Legal audit is a statutory control of the accounts carried out based on internal control(IC).Meanwhile,paradoxically,IC is not always transparent to the legal auditor,but rather a compromise to his expectations.What are the determinants that allow the auditor to adapt to it?This paper proposes the analysis of issues and determinants of the effectiveness of legal audit in the context of an opaque IC.This study is carried out on a sample of 56 limited liability companies in Cameroon,carefully selected based on the existence of an IC service.The determinants explaining the auditor’s effectiveness in his mission are noted.
基金supported by the NationalNatural Science Foundation of China(No.52067013)the Natural Science Foundation of Gansu Province(No.20JR5RA395)as well as the Tianyou Innovation Team of Lanzhou Jiaotong University(TY202010).
文摘In this paper,an improved sag control strategy based on automatic SOC equalization is proposed to solve the problems of slow SOC equalization and excessive bus voltage fluctuation amplitude and offset caused by load and PV power variations in a stand-alone DC microgrid.The strategy includes primary and secondary control.Among them,the primary control suppresses the DC microgrid voltage fluctuation through the I and II section control,and the secondary control aims to correct the P-U curve of the energy storage system and the PV system,thus reducing the steady-state bus voltage excursion.The simulation results demonstrate that the proposed control strategy effectively achieves SOC balancing and enhances the immunity of bus voltage.The proposed strategy improves the voltage fluctuation suppression ability by approximately 39.4%and 43.1%under the PV power and load power fluctuation conditions,respectively.Furthermore,the steady-state deviation of the bus voltage,△U_(dc) is only 0.01–0.1 V,ensuring stable operation of the DC microgrid in fluctuating power environments.
基金supported by Henan Province Higher Education Teaching Reform Research and Practice Project(No.2021SJGLX333)。
文摘Objective:To explore the effect of the Plan-Do-Check-Action(PDCA)cycle on hand hygiene and nosocomial infection quality of or thopedic medical staff.Methods:The whole year of 2021 was selected to monitor the quality of hand hygiene and hospitalization.Follow-up monitoring and real-time recording during the period of morning shift and medical operation concentration time,and compare the compliance of hand hygiene before and after implementation,and evaluate the quality of nosocomial infection.Results:The hand hygiene compliance of doctors and nurses in stage P was 82%.The compliance of medical staff in stage D was 93%.The compliance of stage C was 94%and that of stage A was 95%.The quality score of hospital self-examination nosocomial infection was also significantly increased.Conclusions:The PDCA management cycle can effectively improve the compliance of hand hygiene and the nosocomial infection quality,which is wor thy of circulatory application in or thopedic nosocomial infection quality control,especially improving the quality of hand hygiene.
文摘Three recent breakthroughs due to AI in arts and science serve as motivation:An award winning digital image,protein folding,fast matrix multiplication.Many recent developments in artificial neural networks,particularly deep learning(DL),applied and relevant to computational mechanics(solid,fluids,finite-element technology)are reviewed in detail.Both hybrid and pure machine learning(ML)methods are discussed.Hybrid methods combine traditional PDE discretizations with ML methods either(1)to help model complex nonlinear constitutive relations,(2)to nonlinearly reduce the model order for efficient simulation(turbulence),or(3)to accelerate the simulation by predicting certain components in the traditional integration methods.Here,methods(1)and(2)relied on Long-Short-Term Memory(LSTM)architecture,with method(3)relying on convolutional neural networks.Pure ML methods to solve(nonlinear)PDEs are represented by Physics-Informed Neural network(PINN)methods,which could be combined with attention mechanism to address discontinuous solutions.Both LSTM and attention architectures,together with modern and generalized classic optimizers to include stochasticity for DL networks,are extensively reviewed.Kernel machines,including Gaussian processes,are provided to sufficient depth for more advanced works such as shallow networks with infinite width.Not only addressing experts,readers are assumed familiar with computational mechanics,but not with DL,whose concepts and applications are built up from the basics,aiming at bringing first-time learners quickly to the forefront of research.History and limitations of AI are recounted and discussed,with particular attention at pointing out misstatements or misconceptions of the classics,even in well-known references.Positioning and pointing control of a large-deformable beam is given as an example.
文摘PEM (Proton Exchange Membrane) fuel cell is a promising renewable energy source to a wide range of applications for its clean products and high power density. However, controlling its humidity is a challenging problem due to the interdependence of several phenomena contributing in membrane's water content. This work deals with efficiency improvement of PEM fuel cells via humidity control. An innovative strategy of control based on the model of Ref. [1] is proposed. It consists on regulating gas humidification rates according to the power demand so that to minimize power losses. The proposed control takes into consideration constraints related to humidification in order to avoid dry out or flooding of the membrane. Simulations results show that time-phasing between hydrogen and oxygen humidification rates plays an important role in minimizing power losses. The proposed control shows significant improvement in the fuel cell's efficiency up to 20%.
文摘Yield improvement and advanced defect control can be identified as the driving forces for modeling of industrial bulk crystal growth. Yield improvement is mainly achieved by upscaling of the whole crystal growth apparatus and increased processing windows with more tolerances for parameter variations. Advanced defect control means on one hand a reduction of the number of deficient crystal defects and on the other hand the formation of beneficial crystal defects with a uniform distribution and well defined concentrations in the whole crystal. This "defect engineering" relates to the whole crystal growth process as well as the following cooling and optional annealing processes, respectively. These topics were illustrated in the paper by examples of modeling and experimental results of bulk growth of silicon (Si), gallium arsenide (GaAs), indium phosphide (InP) and calcium fluoride (CaF2). These examples also involve the state of the art of modeling of the most important melt growth techniques, crystal pulling (Czochralski methods) and vertical gradient freeze (Bridgman-type methods).
文摘The fluctuation of active power output of wind farm has many negative impacts on large-scale wind power integration into power grid. In this paper, flywheel energy storage system (FESS) was connected to AC side of the doubly-fed induction generator (DFIG) wind farm to realize smooth control of wind power output. Based on improved wind power prediction algorithm and wind speed-power curve modeling, a new smooth control strategy with the FESS was proposed. The requirement of power system dispatch for wind power prediction and flywheel rotor speed limit were taken into consideration during the process. While smoothing the wind power fluctuation, FESS can track short-term planned output of wind farm. It was demonstrated by quantitative analysis of simulation results that the proposed control strategy can smooth the active power fluctuation of wind farm effectively and thereby improve power quality of the power grid.
文摘Aiming at the problem of network-induced delay and data dropout in networked control system, an improved fuzzy controller is proposed in this paper. Considering the great influence of a controller on the performance of control system, an improved controller with a second order fuzzy controller and network-induced delay compensator being added to the basic fuzzy controller is proposed to realize self-regulation on-line. For this type of controller, neither plant model nor measurement of network delay is required. So it is capable of automatically adjusting quantified factor, pro- portional factor, and integral factor according to the control system error and its derivative. The design makes full use of the advantages of quickness in operation and reduction of steady state error because of its integral function. The con- troller has a good control effect on time-delay and can keep a better performance by self-regulation on-line in the net- work with data dropout and interference. It is good in quickness, adaptability, and robustness, which is favorable for controlling the long time-delay system.
文摘This paper illustrates the benefits of a multivariable linearizing control approach applied to an industrial crystallization process. This relevant approach is declined according to two different strategies: first, a setpoint tracking is proposed for the couple crystal mass/concentration, whereas a second way consists in tracking of crystal content and concentration. The controlled variables, unavailable online, are issued from an observer developed in previous works. The performance of these strategies, which application to cane sugar crystallization constitutes a real novelty, are compared with experimental data issued from a PID-controlled industrial plant. The results reveal a significant improvement of energy efficiency, leading to an economy of more than 10% of energy.
基金supported by the National Natural Science Foundation of China(No.61903291)Key Research and Development Program of Shaanxi Province(No.2022NY-094)。
文摘The variable air volume(VAV)air conditioning system is with strong coupling and large time delay,for which model predictive control(MPC)is normally used to pursue performance improvement.Aiming at the difficulty of the parameter selection of VAV MPC controller which is difficult to make the system have a desired response,a novel tuning method based on machine learning and improved particle swarm optimization(PSO)is proposed.In this method,the relationship between MPC controller parameters and time domain performance indices is established via machine learning.Then the PSO is used to optimize MPC controller parameters to get better performance in terms of time domain indices.In addition,the PSO algorithm is further modified under the principle of population attenuation and event triggering to tune parameters of MPC and reduce the computation time of tuning method.Finally,the effectiveness of the proposed method is validated via a hardware-in-the-loop VAV system.
文摘The aim of the study was to verify the efficacy of the Tone-Control method in inducing a reduction in the tension of the muscles of the shoulder girdle,and therefore a normalisation of posture in the segment.The authors analysed the change in posture,which was related to the muscle tension of the pectoralis major muscle and the trapezius muscle,resulting from the administration of a programme of encoded exercises known as the Tone Control method.The study was conducted on 70 patients with postural back pain,aged between 25 and 81 years and with a mean age of 61.9 years,11 male patients and 59 female patients,who attended group rehabilitation for a minimum of 10 and a maximum of 15 sessions.Acute phase patients,patients on anti-inflammatory pharmacological treatment and patients with hernias or bulging causing thecal sac impingement were excluded from the study.Measurements were taken of the angles of the joints in the scapulohumeral segment during the first and last sessions.The NRS(numeric rating scale)pain scale was administered at the start and end of the cycle of sessions.Conclusions:Patients in the study group experienced improvements in the angle measurements that were proportionally greater than those of the control group,together with a considerable reduction in perceived pain,with an overall improvement in posture and shoulder girdle function.
文摘In the context of the information age, with the causes of the financial deregulation of the bank in the financial industry competition intensifies, the communication of science and technology advancement, there are innovative financial instruments to achieve orgasm. With that, comes the increased risk of commercial banks. China' s banking innovation started late, but rapidly develops. More seriously, in the development of the innovation process, there is not enough emphasis on the legal risk, which causes great risks.
文摘The corruption problem of China's rural cadres has exposed the weakness of the absence of legal control in rural administration. In the face of the problems in the legal control of corruption in rural cadres,it is required to improve the laws and regulations,strengthen law enforcement,and strengthen the supervision and guidance of higher-level party committee and governments to bring the corruption of rural cadres into the rule of law.
基金Supported by the National Natural Science Foundation of China(31201985)the National Key Technology R&D Program(2012BAD26B03)~~
文摘Feeding habit which is regulated by many factors including the intrinsic and external factors, such as appetite, structure of the digestive tract and feed palatability, is an important content in the study of genetic improvement. The genetic regulation is one of the major parts among the researches. This research reported the progress of the polymorphism of genes associated with appetite and its correla- tion with feeding habits, and summarized the studies on improvements of fish feed- ing and protein sources of the artificial feeding in order to provide theoretic basis for cultivating the improved varieties in feeding habit.
基金supported in part by the National Natural Science Foundation of China (62033009)the Creative Activity Plan for Science and Technology Commission of Shanghai (20510712300,21DZ2293500)the Supported by Science Foundation of Donghai Laboratory。
文摘In this paper, the fixed-time event-triggered obstacle avoidance consensus control for a multi-AUV time-varying formation system in a 3D environment is presented by using an improved artificial potential field and leader-follower strategy(IAPF-LF). Firstly, the proposed fixed-time control can achieve the desired multi-AUV formation within a fixed settling time in any initial system state. Secondly, an event-triggered communication strategy is developed to govern the communication among AUVs, and the communication energy consumption can be decremented. The time-varying formation obstacle avoidance control algorithm based on IAPF-LF is designed to avoid static and dynamic obstacles, the desired formation is maintained in the presence of external disturbances, and there is no Zeno behavior under the fixed-time event-triggered consensus control strategy.The stability of the system is proved by the Lyapunov function and inequality scaling. Finally, simulation examples and water pool experiments are reported to verify the performance of the proposed theoretical algorithms.