In this paper the synchronization for two different fractional-order chaotic systems, capable of guaranteeing synchronization error with prescribed performance, is investigated by means of the fractional-order control...In this paper the synchronization for two different fractional-order chaotic systems, capable of guaranteeing synchronization error with prescribed performance, is investigated by means of the fractional-order control method. By prescribed performance synchronization we mean that the synchronization error converges to zero asymptotically, with convergence rate being no less than a certain prescribed function. A fractional-order synchronization controller and an adaptive fractional-order synchronization controller, which can guarantee the prescribed performance of the synchronization error,are proposed for fractional-order chaotic systems with and without disturbances, respectively. Finally, our simulation studies verify and clarify the proposed method.展开更多
This paper gives performance analysis of a three phase Permanent Magnet Synchronous Generator (PMSG) connected to a Vertical Axis Wind Turbine (VAWT). Low speed wind condition (less than 5 m/s) is taken in considerati...This paper gives performance analysis of a three phase Permanent Magnet Synchronous Generator (PMSG) connected to a Vertical Axis Wind Turbine (VAWT). Low speed wind condition (less than 5 m/s) is taken in consideration and the entire simulation is carried in Matlab/Simulink environment. The rated power for the generator is fixed at 1.5 KW and number of pole at 20. It is observed under low wind speed of6 m/s, a turbine having approximately1 mof radius and2.6 mof height develops 150 Nm mechanical torque that can generate power up to 1.5 KW. The generator is designed using modeling tool and is fabricated. The fabricated generator is tested in the laboratory with the simulation result for the error analysis. The range of error is about 5%-27% for the same output power value. The limitations and possible causes for error are presented and discussed.展开更多
In the design of the motor used for electric vehicles(EVS),vibration and noise problems are often ignored,which reduce the reliability and service life of the motor.In this paper,an interior permanent magnet synchrono...In the design of the motor used for electric vehicles(EVS),vibration and noise problems are often ignored,which reduce the reliability and service life of the motor.In this paper,an interior permanent magnet synchronous motor(IPMSM)with high power density is taken as an example,and its electromagnetic vibration and noise problem is investigated and optimized.Firstly,the factors that generate the electromagnetic force harmonic of IPMSM are analyzed by theoretical derivation.Furthermore,the mode and electromagnetic harmonic distribution of the motor are calculated and analyzed by establishing the electromagnetic-structure-sound coupling simulation model.Then,by combining finite element method(FEM)with modern optimization algorithm,an electromagnetic vibration and noise performance optimization method is proposed in the electromagnetic design stage of the motor.Finally,an IPMSM is optimized by this method for electromagnetic vibration and noise performance.The results of comparison between before and after optimization prove the feasibility of the method.展开更多
Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary ca...Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary carbon and nitrogen supply.Therefore,this study aimed to determine glucose release kinetics of various feed ingredients,to investigate a glucose release pattern that is conducive to synchronized carbon–nitrogen supply,and to elucidate the underlying mechanisms by which this synchronization optimizes growth of pigs.Results We analyzed the glucose release kinetics of 23 feed ingredients in vitro and found that their glucose release rates and amounts varied greatly.Based on this,a nitrogen-free diet and 5 purified diets,which represented the observed variations in glucose release rates and quantities among feed ingredients,were designed for 18 ileal-cannulated pigs.The results demonstrated that slower glucose release pattern could disrupt the synchrony of dietary carbon and nitrogen supply,reducing the growth of pigs and increasing nitrogen losses.Specifically,the diet with slower and moderate amounts of glucose release showed a relatively slower release of amino acids.Pigs fed this diet had the lower amino acid digestibility and the enrichment of harmful bacteria,such as Streptococcus,in the terminal ileum.Conversely,the diets with slower and lower glucose release exhibited a relatively rapid release of amino acids but also resulted in poor growth.They increased glucogenic amino acid digestibility and potentially enriched bacteria involved in nitrogen cycling and carbon metabolism.Notably,only the diet with rapid glucose release achieved synchronized and rapid release of nutrients.Pigs fed this diet exhibited higher amino acid digestibility,decreased harmful bacteria enrichment,improved nutrient utilization,and enhanced short-term growth performance.Conclusions Our research analyzed significant differences in glucose release kinetics among swine feed ingredients and revealed that slow glucose release disrupted dietary carbon–nitrogen supply synchrony,shifting amino acid utilization and enriching pathogens,negatively impacting growth and nutrient utilization.Consequently,choosing feed ingredients releasing glucose at a rapid rate to balance dietary carbon and nitrogen supply helps promote pig growth,and ensures efficient feed utilization.展开更多
Objective:Interpersonal brain synchronization(IBS)has emerged as a significant concept in understanding collaborative team dynamics,with functional near-infrared spectroscopy(fNIRS)proving to be a vital tool in its as...Objective:Interpersonal brain synchronization(IBS)has emerged as a significant concept in understanding collaborative team dynamics,with functional near-infrared spectroscopy(fNIRS)proving to be a vital tool in its assessment.This review aims to collate and analyze the literature on the application of fNIRS in various team settings,emphasizing its potential utility in surgical environments.Methods:A thorough search and screening process across multiple databases resulted in 17 studies being reviewed,with a focus on the utilization of fNIRS to measure IBS in different collaborative tasks.This review examined the tasks employed,participant demographics,organizational structures of teams,methodologies for IBS measurement,and correlations between brain synchronization and behavioral measurements.Results:fNIRS emerged as a non-invasive,cost-effective,and portable tool,predominantly used to assess IBS in pair-based tasks with a variety of participant demographics.Wavelet transform coherence was the primary method used for measuring synchronization,particularly in the prefrontal brain region.A consistent correlation was found between increased brain synchronization and enhanced team performance,underscoring the potential of fNIRS in understanding and optimizing team dynamics.Conclusion:This review establishes fNIRS as a promising tool for investigating the neural mechanisms underlying team cooperation,providing invaluable insights for potential applications in surgical settings.While acknowledging the limitations in the current literature,the review highlights the need for further research with larger sample sizes and varied task complexities to solidify the understanding of IBS and its impact on team performance.The ultimate goal is to leverage fNIRS in assessing and improving surgical team dynamics,contributing to improved patient outcomes and safety.展开更多
Dear Editor,This letter proposes a deep synchronization control(DSC) method to synchronize grid-forming converters with power grids. The method involves constructing a novel controller for grid-forming converters base...Dear Editor,This letter proposes a deep synchronization control(DSC) method to synchronize grid-forming converters with power grids. The method involves constructing a novel controller for grid-forming converters based on the stable deep dynamics model. To enhance the performance of the controller, the dynamics model is optimized within the deep reinforcement learning(DRL) framework. Simulation results verify that the proposed method can reduce frequency deviation and improve active power responses.展开更多
Jacket covering fabric is one of the critical materials for the production of synchronous beltswhich are widely used for positive drive in various departments of industry. The successful de-velopment of textured yarn ...Jacket covering fabric is one of the critical materials for the production of synchronous beltswhich are widely used for positive drive in various departments of industry. The successful de-velopment of textured yarn jacket fabric by our lab has filled a domestic vacancy in this respect.In this paper the processing of textured yarn jacket fabric is briefly outlined, its characteristicsexplained and its performance test results given.展开更多
Objective:To isolate and identify microflora and fungal species at different phases during estrus synchronization of ewes and estimate their prevalence;compare the effectiveness of antimicrobial administration to intr...Objective:To isolate and identify microflora and fungal species at different phases during estrus synchronization of ewes and estimate their prevalence;compare the effectiveness of antimicrobial administration to intravaginal sponge on the changes in the vaginal micro-organisms and reproductive performance.Methods: Sixty Egyptian ewes were allocated into three equal groups (G: 1, 2 and 3). G1 was inserted with vaginal sponge containing medroxy-progesterone acetate and served as control;without antimicrobial additive. The other two groups were treated as G1, but sponges were previously injected with ciprofloxacin (G2), while sponges of G3 were injected with ciprofloxacin and clotrimazole. Vaginal swabs were collected from each treated ewe, prior sponge insertion, at sponge withdrawal and 48 h later for microbiological investigation and bacterial count. On the day of sponge removal, 300 IU/eCG was administered for each treated ewe. The identified bacterial strains before sponge insertion were tested for sensitivity with antimicrobial disks.Results:Bacterial isolates before sponge insertion were more sensitive to ciprofloxacin. Frequencies of ewes in estrus;the interval from sponge withdrawal to onset estrus and the duration of estrus were statistically similar among treated groups. The pregnancy rate in G2 (100%) was higher than G1 (66.7%) and G3 (82.4%). The total bacterial count before sponge insertion was similar between all treatments and increased significantly in all groups on the day of sponge withdraw. The prevailing bacteria on D0, D14 and 48 h after sponge removal for all treated groups wereStaphylococcus spp. followed byEscherichia coli. Regarding to fungus species, percentages of isolation increased from 5% (before sponge insertion) to 100.00% and 88.89% at sponge withdraw for G1 and G2, respectively. In G3, the fungus was declined from 10% (before sponge insertion) to 5% (at sponge removal).Conclusions:The concomitant treatments by antimicrobial to the vaginal sponge which used for estrus synchronization in ewes can improve reproductive performance.展开更多
Synchronous machines are dedicated to the specific application. They are generally employed in rolling mills, pumps, fans, and compressors like reprobating and centrifugal drives, pulp and paper processing, water trea...Synchronous machines are dedicated to the specific application. They are generally employed in rolling mills, pumps, fans, and compressors like reprobating and centrifugal drives, pulp and paper processing, water treatment, mining, and in cement industries. As a synchronous motor, the performance is reduced for the given excitation while the load increases. When operated as synchronous generators, both power loads and lighting loads depend on the output from the armature winding. This paper presents an alternative choice in which by providing an additional winding in the stationary armature, when operated as a Double Winding Synchronous Motor (DWSyM), it becomes possible to operate in maximum power factor by adjusting the loads on both the stator windings. When operated as conventional motor, for the load current of 3.5 A, the efficiency is 55% and power factor is 0.55, for the same excitation when second winding is connected to a load current of 1 A, the efficiency is improved to 77.6% and power factor is improved to 0.66. The main focus of this machine is to improve the performance of the machine for the reduced excitation and minimum load. For the reduced excitation, the performance can be improved by loading both the windings. While operated as Double Winding Synchronous Generator (DWSyG), two stator outputs are available which help to separate the power and lighting circuits. Hence, interruption in the lighting circuit can be limited, this machine can be considered as Twin generator.展开更多
To realize the data synchronization between the inertial measurement unit （IMU） and the global positioning system （GPS）, the synchronization technology in the IMU/GPS integrated measurement system of vehicle motio...To realize the data synchronization between the inertial measurement unit （IMU） and the global positioning system （GPS）, the synchronization technology in the IMU/GPS integrated measurement system of vehicle motion parameters is studied. According to the characteristics of the output signals of the IMU and the GPS, without the IMU synchronization signal, the synchronization circuit based on CPLD is designed and developed, which need not alter the configurations of the IMU and GPS. Experiments of measuring vehicle motion parameters, which rely on the synchronization circuit to realize IMU/GPS data synchronization, are made. The driving routes in experiments comprise a curve and a straight line. Experimental results show that the designed circuit can accurately measure the synchronization time difference and the IMU period, and can effectively solve the data synchronization in IMU/GPS integration. Furthermore, the IMU/GPS integrated measurement system based on the synchronization circuit can measure and calculate many vehicle motion parameters in high frequency mode.展开更多
This paper investigates the mixed Ho~ and passive projective synchronization problem for fractional-order （FO） memristor-based neural networks. Our aim is to design a controller such that, though the unavoidable phe...This paper investigates the mixed Ho~ and passive projective synchronization problem for fractional-order （FO） memristor-based neural networks. Our aim is to design a controller such that, though the unavoidable phenomena of time-delay and parameter uncertainty are fully considered, the resulting closed-loop system is asymptotically stable with a mixed H∞ and passive performance level. By combining active and adaptive control methods, a novel hybrid control strategy is designed, which can guarantee the robust stability of the closed-loop system and also ensure a mixed H∞ and passive performance level. Via the application of FO Lyapunov stability theory, the projective synchronization conditions are addressed in terms of linear matrix inequaiity techniques. Finally, two simulation examples are given to illustrate the effectiveness of the proposed method.展开更多
The cluster synchronization problem of complex dynamical networks with each node being a Lurie system with exter- nal disturbances and time-varying delay is investigated in this paper. Some criteria for cluster synchr...The cluster synchronization problem of complex dynamical networks with each node being a Lurie system with exter- nal disturbances and time-varying delay is investigated in this paper. Some criteria for cluster synchronization with desired H∞ performance are presented by using a local linear control scheme. Firstly, sufficient conditions are established to realize cluster synchronization of the Lurie dynamical networks without time delay. Then, the notion of the cluster synchronized region is introduced, and some conditions guaranteeing the cluster synchronized region and unbounded cluster synchro- nized region are derived. Furthermore, the cluster synchronization and cluster synchronized region in the Lurie dynamical networks with time-varying delay are considered. Numerical examples are finally provided to verify and illustrate the theoretical results.展开更多
This paper proposes an adaptive synchronization problem for the master and slave structure of linear systems with nonlinear perturbations and mixed time-varying delays comprising different discrete and distributed tim...This paper proposes an adaptive synchronization problem for the master and slave structure of linear systems with nonlinear perturbations and mixed time-varying delays comprising different discrete and distributed time delays. Using an appropriate Lyapunov-Krasovskii functional, some delay-dependent sufficient conditions and an adaptation law including the master-slave parame- ters are established for designing a delayed synchronization law in terms of linear matrix inequalities（LMIs）. The time-varying controller guarantees the H ∞ synchronization of the two coupled master and slave systems regardless of their initial states. Particularly, it is shown that the synchronization speed can be controlled by adjusting the updated gain of the synchronization signal. Two numerical examples are given to demonstrate the effectiveness of the method.展开更多
Permanent magnet linear synchronous motor(PMLSM)has the advantages of high thrust density and good control accuracy,which can be applied in high-power and high-speed occasions.In this paper,the analytical models are e...Permanent magnet linear synchronous motor(PMLSM)has the advantages of high thrust density and good control accuracy,which can be applied in high-power and high-speed occasions.In this paper,the analytical models are established to obtain the electromagnetic performance for the PMLSMs with dual secondaries and dual primaries.The air-gap flux density and the electromagnetic thrust are also obtained by the finite element model to verify theoretical analysis.Besides,an improved structure is also put forward in order to suppress the thrust fluctuation of the PMLSM.Finally,the advantages and disadvantages of two PMLSMs topologies are listed.These analyses would provide a guide for the design of PMLSMs applied in high-power and high-speed occasions.展开更多
For permanent magnet linear synchronous motor(PMLSM) working at trapezoidal speed for long time, high thrust brings high temperature rise, while low thrust limits dynamic performance. Thus, it is crucial to find a bal...For permanent magnet linear synchronous motor(PMLSM) working at trapezoidal speed for long time, high thrust brings high temperature rise, while low thrust limits dynamic performance. Thus, it is crucial to find a balance between temperature rise and dynamic performance. In this paper, a velocity planning model of the PMLSM at trapezoidal speed based on electromagnetic-fluid-thermal(EFT) field is proposed to obtain the optimal dynamic performance under temperature limitation. In this model, the winding loss is calculated considering the acceleration and deceleration time. The loss model is indirectly verified by the temperature rise experiment of an annular winding sample. The actual working conditions of the PMLSM are simulated by dynamic grid technology to research the influence of acceleration and deceleration on fluid flow in the air gap, and the variation rule of the thermal boundary condition is analyzed. Combined with the above conditions, the temperature rise of a coreless PMLSM(CPMLSM) under the rated working condition is calculated and analyzed in detail. Through this method and several iterations, the optimal dynamic performance under the temperature limitation is achieved. The result is verified by a comparison between simulation and prototype tests, which can help improve the dynamic performance.展开更多
In order to enhance the transient performance of aircraft high voltage DC(HVDC)generation system with wound rotor synchronous machine(WRSM)under a wide speed range,the nonlinear PI multi-loop control strategy is propo...In order to enhance the transient performance of aircraft high voltage DC(HVDC)generation system with wound rotor synchronous machine(WRSM)under a wide speed range,the nonlinear PI multi-loop control strategy is proposed in this paper.Traditional voltage control method is hard to achieve the dynamic performance requirements of the HVDC generation system under a wide speed range,so the nonlinear PI parameter adjustment,load current feedback and speed feedback are added to the voltage and excitation current double loop control.The transfer function of the HVDC generation system is derived,and the relationship between speed,load current and PI parameters is obtained.The PI parameters corresponding to the load at certain speed are used to shorten the adjusting time when the load suddenly changes.The dynamic responses in transient processes are analyzed by experiment.The results illustrate that the WRSM HVDC generator system with this method has better dynamic performance.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11401243 and 61403157)the Fundamental Research Funds for the Central Universities of China(Grant No.GK201504002)the Natural Science Foundation for the Higher Education Institutions of Anhui Province of China(Grant No.KJ2015A256)
文摘In this paper the synchronization for two different fractional-order chaotic systems, capable of guaranteeing synchronization error with prescribed performance, is investigated by means of the fractional-order control method. By prescribed performance synchronization we mean that the synchronization error converges to zero asymptotically, with convergence rate being no less than a certain prescribed function. A fractional-order synchronization controller and an adaptive fractional-order synchronization controller, which can guarantee the prescribed performance of the synchronization error,are proposed for fractional-order chaotic systems with and without disturbances, respectively. Finally, our simulation studies verify and clarify the proposed method.
文摘This paper gives performance analysis of a three phase Permanent Magnet Synchronous Generator (PMSG) connected to a Vertical Axis Wind Turbine (VAWT). Low speed wind condition (less than 5 m/s) is taken in consideration and the entire simulation is carried in Matlab/Simulink environment. The rated power for the generator is fixed at 1.5 KW and number of pole at 20. It is observed under low wind speed of6 m/s, a turbine having approximately1 mof radius and2.6 mof height develops 150 Nm mechanical torque that can generate power up to 1.5 KW. The generator is designed using modeling tool and is fabricated. The fabricated generator is tested in the laboratory with the simulation result for the error analysis. The range of error is about 5%-27% for the same output power value. The limitations and possible causes for error are presented and discussed.
基金This work was supported by the Fundamental Research Funds for the Central Universities(No.2019YJS181).
文摘In the design of the motor used for electric vehicles(EVS),vibration and noise problems are often ignored,which reduce the reliability and service life of the motor.In this paper,an interior permanent magnet synchronous motor(IPMSM)with high power density is taken as an example,and its electromagnetic vibration and noise problem is investigated and optimized.Firstly,the factors that generate the electromagnetic force harmonic of IPMSM are analyzed by theoretical derivation.Furthermore,the mode and electromagnetic harmonic distribution of the motor are calculated and analyzed by establishing the electromagnetic-structure-sound coupling simulation model.Then,by combining finite element method(FEM)with modern optimization algorithm,an electromagnetic vibration and noise performance optimization method is proposed in the electromagnetic design stage of the motor.Finally,an IPMSM is optimized by this method for electromagnetic vibration and noise performance.The results of comparison between before and after optimization prove the feasibility of the method.
基金supported by the National Key Research and Development Program of China(2021YFD1300201)the National Natural Science Foundation of China(32330100 and 32125036)+3 种基金the China Agricultural Research System(CARS-35)2115 Talent Development Program of China Agricultural Universitythe 111 Project(No.B16044)the 2023 Key Project of the Graduate Independent Innovation Research Fund at China Agricultural University。
文摘Background Pigs fed diets with different ingredients but identical nutritional levels show significant differences in growth performance,indicating that growth may also be influenced by the synchronicity of dietary carbon and nitrogen supply.Therefore,this study aimed to determine glucose release kinetics of various feed ingredients,to investigate a glucose release pattern that is conducive to synchronized carbon–nitrogen supply,and to elucidate the underlying mechanisms by which this synchronization optimizes growth of pigs.Results We analyzed the glucose release kinetics of 23 feed ingredients in vitro and found that their glucose release rates and amounts varied greatly.Based on this,a nitrogen-free diet and 5 purified diets,which represented the observed variations in glucose release rates and quantities among feed ingredients,were designed for 18 ileal-cannulated pigs.The results demonstrated that slower glucose release pattern could disrupt the synchrony of dietary carbon and nitrogen supply,reducing the growth of pigs and increasing nitrogen losses.Specifically,the diet with slower and moderate amounts of glucose release showed a relatively slower release of amino acids.Pigs fed this diet had the lower amino acid digestibility and the enrichment of harmful bacteria,such as Streptococcus,in the terminal ileum.Conversely,the diets with slower and lower glucose release exhibited a relatively rapid release of amino acids but also resulted in poor growth.They increased glucogenic amino acid digestibility and potentially enriched bacteria involved in nitrogen cycling and carbon metabolism.Notably,only the diet with rapid glucose release achieved synchronized and rapid release of nutrients.Pigs fed this diet exhibited higher amino acid digestibility,decreased harmful bacteria enrichment,improved nutrient utilization,and enhanced short-term growth performance.Conclusions Our research analyzed significant differences in glucose release kinetics among swine feed ingredients and revealed that slow glucose release disrupted dietary carbon–nitrogen supply synchrony,shifting amino acid utilization and enriching pathogens,negatively impacting growth and nutrient utilization.Consequently,choosing feed ingredients releasing glucose at a rapid rate to balance dietary carbon and nitrogen supply helps promote pig growth,and ensures efficient feed utilization.
文摘Objective:Interpersonal brain synchronization(IBS)has emerged as a significant concept in understanding collaborative team dynamics,with functional near-infrared spectroscopy(fNIRS)proving to be a vital tool in its assessment.This review aims to collate and analyze the literature on the application of fNIRS in various team settings,emphasizing its potential utility in surgical environments.Methods:A thorough search and screening process across multiple databases resulted in 17 studies being reviewed,with a focus on the utilization of fNIRS to measure IBS in different collaborative tasks.This review examined the tasks employed,participant demographics,organizational structures of teams,methodologies for IBS measurement,and correlations between brain synchronization and behavioral measurements.Results:fNIRS emerged as a non-invasive,cost-effective,and portable tool,predominantly used to assess IBS in pair-based tasks with a variety of participant demographics.Wavelet transform coherence was the primary method used for measuring synchronization,particularly in the prefrontal brain region.A consistent correlation was found between increased brain synchronization and enhanced team performance,underscoring the potential of fNIRS in understanding and optimizing team dynamics.Conclusion:This review establishes fNIRS as a promising tool for investigating the neural mechanisms underlying team cooperation,providing invaluable insights for potential applications in surgical settings.While acknowledging the limitations in the current literature,the review highlights the need for further research with larger sample sizes and varied task complexities to solidify the understanding of IBS and its impact on team performance.The ultimate goal is to leverage fNIRS in assessing and improving surgical team dynamics,contributing to improved patient outcomes and safety.
基金supported in part by the National Natural Science Foundation of China(62033005,62273270)the Natural Science Foundation of Shaanxi Province(2023JC-XJ17)
文摘Dear Editor,This letter proposes a deep synchronization control(DSC) method to synchronize grid-forming converters with power grids. The method involves constructing a novel controller for grid-forming converters based on the stable deep dynamics model. To enhance the performance of the controller, the dynamics model is optimized within the deep reinforcement learning(DRL) framework. Simulation results verify that the proposed method can reduce frequency deviation and improve active power responses.
文摘Jacket covering fabric is one of the critical materials for the production of synchronous beltswhich are widely used for positive drive in various departments of industry. The successful de-velopment of textured yarn jacket fabric by our lab has filled a domestic vacancy in this respect.In this paper the processing of textured yarn jacket fabric is briefly outlined, its characteristicsexplained and its performance test results given.
文摘Objective:To isolate and identify microflora and fungal species at different phases during estrus synchronization of ewes and estimate their prevalence;compare the effectiveness of antimicrobial administration to intravaginal sponge on the changes in the vaginal micro-organisms and reproductive performance.Methods: Sixty Egyptian ewes were allocated into three equal groups (G: 1, 2 and 3). G1 was inserted with vaginal sponge containing medroxy-progesterone acetate and served as control;without antimicrobial additive. The other two groups were treated as G1, but sponges were previously injected with ciprofloxacin (G2), while sponges of G3 were injected with ciprofloxacin and clotrimazole. Vaginal swabs were collected from each treated ewe, prior sponge insertion, at sponge withdrawal and 48 h later for microbiological investigation and bacterial count. On the day of sponge removal, 300 IU/eCG was administered for each treated ewe. The identified bacterial strains before sponge insertion were tested for sensitivity with antimicrobial disks.Results:Bacterial isolates before sponge insertion were more sensitive to ciprofloxacin. Frequencies of ewes in estrus;the interval from sponge withdrawal to onset estrus and the duration of estrus were statistically similar among treated groups. The pregnancy rate in G2 (100%) was higher than G1 (66.7%) and G3 (82.4%). The total bacterial count before sponge insertion was similar between all treatments and increased significantly in all groups on the day of sponge withdraw. The prevailing bacteria on D0, D14 and 48 h after sponge removal for all treated groups wereStaphylococcus spp. followed byEscherichia coli. Regarding to fungus species, percentages of isolation increased from 5% (before sponge insertion) to 100.00% and 88.89% at sponge withdraw for G1 and G2, respectively. In G3, the fungus was declined from 10% (before sponge insertion) to 5% (at sponge removal).Conclusions:The concomitant treatments by antimicrobial to the vaginal sponge which used for estrus synchronization in ewes can improve reproductive performance.
文摘Synchronous machines are dedicated to the specific application. They are generally employed in rolling mills, pumps, fans, and compressors like reprobating and centrifugal drives, pulp and paper processing, water treatment, mining, and in cement industries. As a synchronous motor, the performance is reduced for the given excitation while the load increases. When operated as synchronous generators, both power loads and lighting loads depend on the output from the armature winding. This paper presents an alternative choice in which by providing an additional winding in the stationary armature, when operated as a Double Winding Synchronous Motor (DWSyM), it becomes possible to operate in maximum power factor by adjusting the loads on both the stator windings. When operated as conventional motor, for the load current of 3.5 A, the efficiency is 55% and power factor is 0.55, for the same excitation when second winding is connected to a load current of 1 A, the efficiency is improved to 77.6% and power factor is improved to 0.66. The main focus of this machine is to improve the performance of the machine for the reduced excitation and minimum load. For the reduced excitation, the performance can be improved by loading both the windings. While operated as Double Winding Synchronous Generator (DWSyG), two stator outputs are available which help to separate the power and lighting circuits. Hence, interruption in the lighting circuit can be limited, this machine can be considered as Twin generator.
文摘To realize the data synchronization between the inertial measurement unit （IMU） and the global positioning system （GPS）, the synchronization technology in the IMU/GPS integrated measurement system of vehicle motion parameters is studied. According to the characteristics of the output signals of the IMU and the GPS, without the IMU synchronization signal, the synchronization circuit based on CPLD is designed and developed, which need not alter the configurations of the IMU and GPS. Experiments of measuring vehicle motion parameters, which rely on the synchronization circuit to realize IMU/GPS data synchronization, are made. The driving routes in experiments comprise a curve and a straight line. Experimental results show that the designed circuit can accurately measure the synchronization time difference and the IMU period, and can effectively solve the data synchronization in IMU/GPS integration. Furthermore, the IMU/GPS integrated measurement system based on the synchronization circuit can measure and calculate many vehicle motion parameters in high frequency mode.
基金Supported by National Natural Science Foundation of China under Grant Nos.U1604146,U1404610,61473115,61203047Science and Technology Research Project in Henan Province under Grant Nos.152102210273,162102410024Foundation for the University Technological Innovative Talents of Henan Province under Grant No.18HASTIT019
文摘This paper investigates the mixed Ho~ and passive projective synchronization problem for fractional-order （FO） memristor-based neural networks. Our aim is to design a controller such that, though the unavoidable phenomena of time-delay and parameter uncertainty are fully considered, the resulting closed-loop system is asymptotically stable with a mixed H∞ and passive performance level. By combining active and adaptive control methods, a novel hybrid control strategy is designed, which can guarantee the robust stability of the closed-loop system and also ensure a mixed H∞ and passive performance level. Via the application of FO Lyapunov stability theory, the projective synchronization conditions are addressed in terms of linear matrix inequaiity techniques. Finally, two simulation examples are given to illustrate the effectiveness of the proposed method.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61075065,60774045,and U1134108)the Talent Introduction Scientific Research Foundation of Northwest University for Nationalities(Grant No.xbmuyjrc201304)the Foundation for Young Talents of Gansu Province,China(Grant No.1208RJYA013)
文摘The cluster synchronization problem of complex dynamical networks with each node being a Lurie system with exter- nal disturbances and time-varying delay is investigated in this paper. Some criteria for cluster synchronization with desired H∞ performance are presented by using a local linear control scheme. Firstly, sufficient conditions are established to realize cluster synchronization of the Lurie dynamical networks without time delay. Then, the notion of the cluster synchronized region is introduced, and some conditions guaranteeing the cluster synchronized region and unbounded cluster synchro- nized region are derived. Furthermore, the cluster synchronization and cluster synchronized region in the Lurie dynamical networks with time-varying delay are considered. Numerical examples are finally provided to verify and illustrate the theoretical results.
文摘This paper proposes an adaptive synchronization problem for the master and slave structure of linear systems with nonlinear perturbations and mixed time-varying delays comprising different discrete and distributed time delays. Using an appropriate Lyapunov-Krasovskii functional, some delay-dependent sufficient conditions and an adaptation law including the master-slave parame- ters are established for designing a delayed synchronization law in terms of linear matrix inequalities（LMIs）. The time-varying controller guarantees the H ∞ synchronization of the two coupled master and slave systems regardless of their initial states. Particularly, it is shown that the synchronization speed can be controlled by adjusting the updated gain of the synchronization signal. Two numerical examples are given to demonstrate the effectiveness of the method.
基金This work has been partly supported in part by National Natural Science Foundation of China under Grants 51877093 and 51707079in part by the National Key Research and Development Program of China under Grant YS2018YFGH000200,in part by the Key Technical Innovation Program of Hubei Province under Grant 2019AAA026.
文摘Permanent magnet linear synchronous motor(PMLSM)has the advantages of high thrust density and good control accuracy,which can be applied in high-power and high-speed occasions.In this paper,the analytical models are established to obtain the electromagnetic performance for the PMLSMs with dual secondaries and dual primaries.The air-gap flux density and the electromagnetic thrust are also obtained by the finite element model to verify theoretical analysis.Besides,an improved structure is also put forward in order to suppress the thrust fluctuation of the PMLSM.Finally,the advantages and disadvantages of two PMLSMs topologies are listed.These analyses would provide a guide for the design of PMLSMs applied in high-power and high-speed occasions.
基金supported in part by the National Natural Science Foundation of China under Grant 52022040in part by the Postgraduate Research&Practice Innovation Program of NUAA。
文摘For permanent magnet linear synchronous motor(PMLSM) working at trapezoidal speed for long time, high thrust brings high temperature rise, while low thrust limits dynamic performance. Thus, it is crucial to find a balance between temperature rise and dynamic performance. In this paper, a velocity planning model of the PMLSM at trapezoidal speed based on electromagnetic-fluid-thermal(EFT) field is proposed to obtain the optimal dynamic performance under temperature limitation. In this model, the winding loss is calculated considering the acceleration and deceleration time. The loss model is indirectly verified by the temperature rise experiment of an annular winding sample. The actual working conditions of the PMLSM are simulated by dynamic grid technology to research the influence of acceleration and deceleration on fluid flow in the air gap, and the variation rule of the thermal boundary condition is analyzed. Combined with the above conditions, the temperature rise of a coreless PMLSM(CPMLSM) under the rated working condition is calculated and analyzed in detail. Through this method and several iterations, the optimal dynamic performance under the temperature limitation is achieved. The result is verified by a comparison between simulation and prototype tests, which can help improve the dynamic performance.
基金supported by funded by"Ye Qisun"Joint Foundation Project supported by the State Key Program of National Natural Science Foundation of China under Award U2141223.
文摘In order to enhance the transient performance of aircraft high voltage DC(HVDC)generation system with wound rotor synchronous machine(WRSM)under a wide speed range,the nonlinear PI multi-loop control strategy is proposed in this paper.Traditional voltage control method is hard to achieve the dynamic performance requirements of the HVDC generation system under a wide speed range,so the nonlinear PI parameter adjustment,load current feedback and speed feedback are added to the voltage and excitation current double loop control.The transfer function of the HVDC generation system is derived,and the relationship between speed,load current and PI parameters is obtained.The PI parameters corresponding to the load at certain speed are used to shorten the adjusting time when the load suddenly changes.The dynamic responses in transient processes are analyzed by experiment.The results illustrate that the WRSM HVDC generator system with this method has better dynamic performance.
