With the aid of the latest fiber optic sensing technology parameters in the cure process of ther- mosetting resin-matrix composite, such as temperature, viscosity,void and residual stress, can be monitored entirely an...With the aid of the latest fiber optic sensing technology parameters in the cure process of ther- mosetting resin-matrix composite, such as temperature, viscosity,void and residual stress, can be monitored entirely and efficiently.In this paper, experiment results of viscosity measurement in composite cure process in autoclave using fiber optic sensors are presented. Based on the sensed information, a computer program is utilized to control the cure process. With this technology, the cure process becomes more apparent and controllable, which will greatly improve the cured products and reduce the cost.展开更多
A new measurement device,consisting of swirling blades and capsule-shaped throttling elements,is proposed in this study to eliminate typical measurement errors caused by complex flow patterns in gas-liquid flow.The sw...A new measurement device,consisting of swirling blades and capsule-shaped throttling elements,is proposed in this study to eliminate typical measurement errors caused by complex flow patterns in gas-liquid flow.The swirling blades are used to transform the complex flow pattern into a forced annular flow.Drawing on the research of existing blockage flow meters and also exploiting the single-phase flow measurement theory,a formula is introduced to measure the phase-separated flow of gas and liquid.The formula requires the pressure ratio,Lockhart-Martinelli number(L-M number),and the gas phase Froude number.The unknown parameters appearing in the formula are fitted through numerical simulation using computational fluid dynamics(CFD),which involves a comprehensive analysis of the flow field inside the device from multiple perspectives,and takes into account the influence of pressure fluctuations.Finally,the measurement model is validated through an experimental error analysis.The results demonstrate that the measurement error can be maintained within±8%for various flow patterns,including stratified flow,bubble flow,and wave flow.展开更多
It is important to know whether the laws or phenomena in statistical physics for natural systems with non-adaptive agents still hold for social human systems with adaptive agents, because this implies whether it is po...It is important to know whether the laws or phenomena in statistical physics for natural systems with non-adaptive agents still hold for social human systems with adaptive agents, because this implies whether it is possible to study or understand social human systems by using statistical physics originating from natural systems. For this purpose, we review the role of human adaptability in four kinds of specific human behaviors, namely, normal behavior, herd behavior, contrarian behavior, and hedge behavior. The approach is based on controlled experiments in the framework of market-directed resource-allocation games. The role of the controlled experiments could be at least two-fold： adopting the real human decision-making process so that the system under consideration could reflect the performance of genuine human beings; making it possible to obtain macroscopic physical properties of a human system by tuning a particular factor of the system, thus directly revealing cause and effect. As a result, both computer simulations and theoretical analyses help to show a few counterparts of some laws or phenomena in statistical physics for social human systems： two-phase phenomena or phase transitions, entropy-related phenomena, and a non-equilibrium steady state. This review highlights the role of human adaptability in these counterparts, and makes it possible to study or understand some particular social human systems by means of statistical physics coming from natural systems.展开更多
With an AGCM/ mixed-layer ocean model, a numerical experiment to investigate the ef-fects of Kuwait oil fire and volcanoes in Philippines and Japan on atmospheric general cireulationand climate is camed out. It is sho...With an AGCM/ mixed-layer ocean model, a numerical experiment to investigate the ef-fects of Kuwait oil fire and volcanoes in Philippines and Japan on atmospheric general cireulationand climate is camed out. It is shown from the simulation that the effect of smoke on climate issignificant near the smoke sources, and quite weak-and-indirect in the distant areas. In the experi-ment, it is not found that the smoke had a significant effect on SST anomialy along the tropicaloceans and flood in Yangtze-Huaihe river's basin of China in the spring and summer of 1991.展开更多
The experimental control system of the superelastic hose instability is based on S7-200PLC as controller. The superelastic hoses are sealed at their both ends. The breakdown condition of that is taken as the object of...The experimental control system of the superelastic hose instability is based on S7-200PLC as controller. The superelastic hoses are sealed at their both ends. The breakdown condition of that is taken as the object of study under different combined and working conditions. The upper computer of the experimental bench adopts MCGS configuration software. The test of experiment can meet the control and real-time monitoring of experimental platform conditions. In the experiment,we measure and monitor the data of temperature,tensile force,pressure and so on by the analog modules. During the process of experiment,the actuators like the solenoid valve and the motor are controlled by the switch. The paper describes that the constitution of experimental control system of the superelastic hose instability, control function and the achievement of monitoring condition. It is convenient to operate in the control system,the design cost is low,the man-machine interface is simple and understandable,and the experimental control system will be significant in bio-engineering and medical research.展开更多
In this paper, lab scale production carried out of calcium carbonate in 400 mL open cylindrical beaker reactor following fuzzy logic approach is reported. 10 grams of Calcium hydroxide is mixed in 250 mL deionized wat...In this paper, lab scale production carried out of calcium carbonate in 400 mL open cylindrical beaker reactor following fuzzy logic approach is reported. 10 grams of Calcium hydroxide is mixed in 250 mL deionized water. Continuous jet supply of carbon dioxide is maintained at controlled flow rate. Reaction histories are noted for different reaction temperatures. Continuous constant magnetic stirring is applied to maintain homogeneity. The data obtained is fuzzified by constructing universe of discourse of temperature, reaction time, and amounts of reactants with reaction conversion. Rule based model is tabulated and results show that fuzzy logic approach is promising to set on data to plan and scale up the process. It is also found that a jump can not be made at this time with few studies of fuzzy logic applications to physiochemical processes unless otherwise amassing and storing up plentiful deduced explorations.展开更多
The exploration of fracture internal fixation materials has been one of the research hotspots in the field of biomedical materials.The traditional internal fixation material for fracture is metal fixation.Although its...The exploration of fracture internal fixation materials has been one of the research hotspots in the field of biomedical materials.The traditional internal fixation material for fracture is metal fixation.Although its mechanical strength is very large,it can not be degraded and absorbed in human body after implantation of human body or canine joint,which requires a secondary operation to remove,which not only brings pain to patients,but also causes economic pay.[1]Therefore,the development of a biodegradable fracture internal fixation material has become the goal of many researchers.Polylactic acid(PLA)is nontoxic and harmless,has good biocompatibility and strong mechanical properties.It can be degraded in vivo after implantation.The degradation products are CO2 and H2O.[2]For the study of the feasibility of polylactic acid as a substitute for common fracture fixation materials,18 northern Chinese pastoral dogs were randomly divided into blank group,PLA group and plate group.The data were recorded according to the Wakitani score from the first week to the fifteenth week after operation.First,all the indexes were divided into two categories by principal component analysis[3],then the blank group,steel plate group and PLA group were fitted and compared.Finally,it is concluded that PLA is more beneficial to joint repair than steel plate.展开更多
The mathematical models of electro-hydraulic speed control system using series of pipesis presented. The principle of pipe effection on dynamics of the system is developed. Computersimulation and physical experiment a...The mathematical models of electro-hydraulic speed control system using series of pipesis presented. The principle of pipe effection on dynamics of the system is developed. Computersimulation and physical experiment are also carried out. The experimental results show that a rightchoosing of serial pipe for electro-hydraulic system enables the dynamic response of the system tobe improved effectively.展开更多
In this paper, simulated and experimental results on the conical tank level control are presented. PI/PID controllers of integer order （IO） as well as of fractional order （FO） are studied and compared. The tuning ...In this paper, simulated and experimental results on the conical tank level control are presented. PI/PID controllers of integer order （IO） as well as of fractional order （FO） are studied and compared. The tuning parameters are obtained first by using root locus （RL） and Ziegler and Nichols methods, for comparison purposes. Next, particle swarm optimization （PSO） is employed to determine the optimal controllers＇ parameters using as fitness function the integral of the absolute value of tracking error （IAE）. From the experimental results it is concluded that PI/FOPI are the controllers presenting the lowest IAE indexes, whereas PID/FOPID controllers present the lowest energy consumption by the control signal.展开更多
Spray coating of polymer latex onto fertilizer particles in a fiuidized bed for producing controlled-release urea is an environment friendly technology as it does not need any toxic organic solvent. Since the spray co...Spray coating of polymer latex onto fertilizer particles in a fiuidized bed for producing controlled-release urea is an environment friendly technology as it does not need any toxic organic solvent. Since the spray coating process in a fluidized bed occurs in the presence of particle collisions, the coating of the particles is random, intermittent and multiple, thus making it difficult to investigate the film formation process. In this paper, an experimental model apparatus was designed and used to investigate the effects of the key factors in the spray coating process. This apparatus reasonably simplified the complex process to avoid particle collisions and randomness in the coating. The intermittent coating in the fluidized bed was modeled by periodic coating and dewatering in the experimental apparatus. A large area film was obtained, and the film permeability was measured. The effects of atomizing gas flow rate, spray rate of latex, solid content of latex and gas temperature on film structure and film permeability were investigated. It was found that water transfer played a dominant role in the spray coating process.展开更多
Experimenial studies on active acoustic fiutter control are carried out successfully in wind-tunnel after the theoretical study The experdrients verify the theory presented in the reference[1] and give valuable experi...Experimenial studies on active acoustic fiutter control are carried out successfully in wind-tunnel after the theoretical study The experdrients verify the theory presented in the reference[1] and give valuable experimeotal results which predict a prondsing future of applying new techology and new ideas to the area of vibration induced by flow.展开更多
Controlled experiments are widely used in many applications to investigate the causal relationship between input factors and experimental outcomes.A completely randomised design is usually used to randomly assign trea...Controlled experiments are widely used in many applications to investigate the causal relationship between input factors and experimental outcomes.A completely randomised design is usually used to randomly assign treatment levels to experimental units.When covariates of the experimental units are available,the experimental design should achieve covariate balancing among the treatment groups,such that the statistical inference of the treatment effects is not confounded with any possible effects of covariates.However,covariate imbalance often exists,because the experiment is carried out based on a single realisation of the complete randomisation.It is more likely to occur and worsen when the size of the experimental units is small or moderate.In this paper,we introduce a new covariate balancing criterion,which measures the differences between kernel density estimates of the covariates of treatment groups.To achieve covariate balance before the treatments are randomly assigned,we partition the experimental units by minimising the criterion,then randomly assign the treatment levels to the partitioned groups.Through numerical examples,weshow that the proposed partition approach can improve the accuracy of the difference-in-mean estimator and outperforms the complete randomisation and rerandomisation approaches.展开更多
Agent-based modeling and controlled human experiments serve as two fundamental research methods in the field of econophysics. Agent-based modeling has been in development for over 20 years, but how to design virtual a...Agent-based modeling and controlled human experiments serve as two fundamental research methods in the field of econophysics. Agent-based modeling has been in development for over 20 years, but how to design virtual agents with high levels of human-like ＂intelligence＂ remains a challenge. On the other hand, experimental econophysics is an emerging field; however, there is a lack of experience and paradigms related to the field. Here, we review some of the most recent research results obtained through the use of these two methods concerning financial problems such as chaos, leverage, and business cycles. We also review the principles behind assessments of agents＇ intelligence levels, and some relevant designs for human experiments. The main theme of this review is to show that by combining theory, agent-based modeling, and controlled human experiments, one can garner more reliable and credible results on account of a better verification of theory; accordingly, this way, a wider range of economic and financial problems and phenomena can be studied.展开更多
A kind of new acoustic liner with adjustable impedance has been proposed. At the same time, a set of control system has been designed for this kind of liner. Many experimental results have been obtained based on this ...A kind of new acoustic liner with adjustable impedance has been proposed. At the same time, a set of control system has been designed for this kind of liner. Many experimental results have been obtained based on this control system. In fact, the present investigation shows the possibi1ity of active control of sound absorption coefficient or impedance of a liner according to external sound source condition by means of a standing wave tube. The experimental results show that the sound absorption coefficient of the liner can keep optimal under any sound source condition by controlling the cavity depth and the flow rate through the perforated plate of the liner. In addition, hoth the resistance and the reactance of the liner can also be controlled independently corresponding to any given condition. which is necessary to control unsteady How in turbomachinery.展开更多
This paper is a quantitative analysis of the role of awareness in English prepositional structure learning in relation to Schmidt's noticing hypothesis about processing the target language form. The purpose is to ...This paper is a quantitative analysis of the role of awareness in English prepositional structure learning in relation to Schmidt's noticing hypothesis about processing the target language form. The purpose is to identify the long-perplexing problem that Chinese students are reluctant to produce English prepositional structure in their writing. The research is a controlled experiment in a translation-based setting which provides empirical support for the claim that the level of awareness plays a crucial role in the learners' intake and written production the target form. The implication is that a more explicit pedagogical approach may be necessary.展开更多
Background The China Spallation Neutron Source(CSNS)accelerator consists of an 80 MeV H-LINAC,a 1.6 GeV rapid cycling synchrotron(RCS)and two beam transport lines.The uncontrolled beam may permanently damage the compo...Background The China Spallation Neutron Source(CSNS)accelerator consists of an 80 MeV H-LINAC,a 1.6 GeV rapid cycling synchrotron(RCS)and two beam transport lines.The uncontrolled beam may permanently damage the components or lead to very high residual radiation dose along the beam line.So the equipment protection must be deliberately designed and implemented.Purpose The machine protection system(MPS)protects components from being damaged by the beam.The response time requirement for the CSNS MPS is less than 20 ms,so the PLC(programmable logic controller)was adopted to implement the interlock logic.Methods The MPS was implemented as a two-tier architecture system,and developed through utilizing PLC and Experimental Physics and Industrial Control System(EPICS)software toolkits.The application logic was taken into careful consideration during the implementation stage.An embedded CPU module can function as an IOC accessing PLC I/O modules through the sequence CPU,with an embedded Linux operation system.Results The interlock logic and heartbeat functions were tested with all functions ok.Time consumption has been measured thoroughly since the important requirement,which is around 15 ms to stop the beam.Conclusions MPS was completed in Sep.2017 and then put into operation.It has been operating smoothly for more than 3 years.MPS has played an important role in every stage of CSNS’s commissioning and operation and achieved high reliability during the user’s experiment operation.The accelerator recently runs stably with low equipment failure.展开更多
Purpose Hundreds of digital beam position monitor processors(DBPM)are required to be produced during the construction of projects such as High Energy Photon Source(HEPS)and the upgrade project of the Beijing Electron ...Purpose Hundreds of digital beam position monitor processors(DBPM)are required to be produced during the construction of projects such as High Energy Photon Source(HEPS)and the upgrade project of the Beijing Electron Positron Collider(BEPCII),which brings great challenges to the test work.In order to achieve accurate,fast,and complete mass production tests of DBPMs,an automatic test system(ATS)has been developed in this article.Methods According to the test items of DBPM,the standardized testing softwareflow is designed based on virtual instru-ment program control technology and experimental physics and industrial control system(EPICS),which realize automatic adjustment of test parameters and automatic acquisition of test result data.Results and conclusions The ATS can realize one-button testing of channel coefficients,channel linearity,attenuator linearity,beam current dependence(BCD)and sampling signal-to-noise ratio(SNR),and generate test reports.The total test time is less than 3 minutes,which is significantly more efficient compared to manual testing.More than 90 BEPCII DBPMs has been tested by this ATS in the lab.The test results proved that such a system could automatically recognize defective products and satisfy the requirements of mass testing.展开更多
文摘With the aid of the latest fiber optic sensing technology parameters in the cure process of ther- mosetting resin-matrix composite, such as temperature, viscosity,void and residual stress, can be monitored entirely and efficiently.In this paper, experiment results of viscosity measurement in composite cure process in autoclave using fiber optic sensors are presented. Based on the sensed information, a computer program is utilized to control the cure process. With this technology, the cure process becomes more apparent and controllable, which will greatly improve the cured products and reduce the cost.
基金Supported By Open Fund of Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering(Yangtze University),YQZC202309.
文摘A new measurement device,consisting of swirling blades and capsule-shaped throttling elements,is proposed in this study to eliminate typical measurement errors caused by complex flow patterns in gas-liquid flow.The swirling blades are used to transform the complex flow pattern into a forced annular flow.Drawing on the research of existing blockage flow meters and also exploiting the single-phase flow measurement theory,a formula is introduced to measure the phase-separated flow of gas and liquid.The formula requires the pressure ratio,Lockhart-Martinelli number(L-M number),and the gas phase Froude number.The unknown parameters appearing in the formula are fitted through numerical simulation using computational fluid dynamics(CFD),which involves a comprehensive analysis of the flow field inside the device from multiple perspectives,and takes into account the influence of pressure fluctuations.Finally,the measurement model is validated through an experimental error analysis.The results demonstrate that the measurement error can be maintained within±8%for various flow patterns,including stratified flow,bubble flow,and wave flow.
基金supported by the National Natural Science Foundation of China (Grant Nos. 11075035 and 11222544)the Fok Ying Tung Education Foundation,China(Grant No. 131008)+2 种基金the Program for New Century Excellent Talents in University,China (Grant No. NCET-12-0121)the Shanghai Rising-Star Program,China(Grant No. 12QA1400200)the Fundamental Research Funds for the Central Universities,China
文摘It is important to know whether the laws or phenomena in statistical physics for natural systems with non-adaptive agents still hold for social human systems with adaptive agents, because this implies whether it is possible to study or understand social human systems by using statistical physics originating from natural systems. For this purpose, we review the role of human adaptability in four kinds of specific human behaviors, namely, normal behavior, herd behavior, contrarian behavior, and hedge behavior. The approach is based on controlled experiments in the framework of market-directed resource-allocation games. The role of the controlled experiments could be at least two-fold： adopting the real human decision-making process so that the system under consideration could reflect the performance of genuine human beings; making it possible to obtain macroscopic physical properties of a human system by tuning a particular factor of the system, thus directly revealing cause and effect. As a result, both computer simulations and theoretical analyses help to show a few counterparts of some laws or phenomena in statistical physics for social human systems： two-phase phenomena or phase transitions, entropy-related phenomena, and a non-equilibrium steady state. This review highlights the role of human adaptability in these counterparts, and makes it possible to study or understand some particular social human systems by means of statistical physics coming from natural systems.
文摘With an AGCM/ mixed-layer ocean model, a numerical experiment to investigate the ef-fects of Kuwait oil fire and volcanoes in Philippines and Japan on atmospheric general cireulationand climate is camed out. It is shown from the simulation that the effect of smoke on climate issignificant near the smoke sources, and quite weak-and-indirect in the distant areas. In the experi-ment, it is not found that the smoke had a significant effect on SST anomialy along the tropicaloceans and flood in Yangtze-Huaihe river's basin of China in the spring and summer of 1991.
文摘The experimental control system of the superelastic hose instability is based on S7-200PLC as controller. The superelastic hoses are sealed at their both ends. The breakdown condition of that is taken as the object of study under different combined and working conditions. The upper computer of the experimental bench adopts MCGS configuration software. The test of experiment can meet the control and real-time monitoring of experimental platform conditions. In the experiment,we measure and monitor the data of temperature,tensile force,pressure and so on by the analog modules. During the process of experiment,the actuators like the solenoid valve and the motor are controlled by the switch. The paper describes that the constitution of experimental control system of the superelastic hose instability, control function and the achievement of monitoring condition. It is convenient to operate in the control system,the design cost is low,the man-machine interface is simple and understandable,and the experimental control system will be significant in bio-engineering and medical research.
文摘In this paper, lab scale production carried out of calcium carbonate in 400 mL open cylindrical beaker reactor following fuzzy logic approach is reported. 10 grams of Calcium hydroxide is mixed in 250 mL deionized water. Continuous jet supply of carbon dioxide is maintained at controlled flow rate. Reaction histories are noted for different reaction temperatures. Continuous constant magnetic stirring is applied to maintain homogeneity. The data obtained is fuzzified by constructing universe of discourse of temperature, reaction time, and amounts of reactants with reaction conversion. Rule based model is tabulated and results show that fuzzy logic approach is promising to set on data to plan and scale up the process. It is also found that a jump can not be made at this time with few studies of fuzzy logic applications to physiochemical processes unless otherwise amassing and storing up plentiful deduced explorations.
文摘The exploration of fracture internal fixation materials has been one of the research hotspots in the field of biomedical materials.The traditional internal fixation material for fracture is metal fixation.Although its mechanical strength is very large,it can not be degraded and absorbed in human body after implantation of human body or canine joint,which requires a secondary operation to remove,which not only brings pain to patients,but also causes economic pay.[1]Therefore,the development of a biodegradable fracture internal fixation material has become the goal of many researchers.Polylactic acid(PLA)is nontoxic and harmless,has good biocompatibility and strong mechanical properties.It can be degraded in vivo after implantation.The degradation products are CO2 and H2O.[2]For the study of the feasibility of polylactic acid as a substitute for common fracture fixation materials,18 northern Chinese pastoral dogs were randomly divided into blank group,PLA group and plate group.The data were recorded according to the Wakitani score from the first week to the fifteenth week after operation.First,all the indexes were divided into two categories by principal component analysis[3],then the blank group,steel plate group and PLA group were fitted and compared.Finally,it is concluded that PLA is more beneficial to joint repair than steel plate.
文摘The mathematical models of electro-hydraulic speed control system using series of pipesis presented. The principle of pipe effection on dynamics of the system is developed. Computersimulation and physical experiment are also carried out. The experimental results show that a rightchoosing of serial pipe for electro-hydraulic system enables the dynamic response of the system tobe improved effectively.
文摘In this paper, simulated and experimental results on the conical tank level control are presented. PI/PID controllers of integer order （IO） as well as of fractional order （FO） are studied and compared. The tuning parameters are obtained first by using root locus （RL） and Ziegler and Nichols methods, for comparison purposes. Next, particle swarm optimization （PSO） is employed to determine the optimal controllers＇ parameters using as fitness function the integral of the absolute value of tracking error （IAE）. From the experimental results it is concluded that PI/FOPI are the controllers presenting the lowest IAE indexes, whereas PID/FOPID controllers present the lowest energy consumption by the control signal.
基金financial support of this study by the National Natural Science Foundation of China (NSFC No. 20876085)
文摘Spray coating of polymer latex onto fertilizer particles in a fiuidized bed for producing controlled-release urea is an environment friendly technology as it does not need any toxic organic solvent. Since the spray coating process in a fluidized bed occurs in the presence of particle collisions, the coating of the particles is random, intermittent and multiple, thus making it difficult to investigate the film formation process. In this paper, an experimental model apparatus was designed and used to investigate the effects of the key factors in the spray coating process. This apparatus reasonably simplified the complex process to avoid particle collisions and randomness in the coating. The intermittent coating in the fluidized bed was modeled by periodic coating and dewatering in the experimental apparatus. A large area film was obtained, and the film permeability was measured. The effects of atomizing gas flow rate, spray rate of latex, solid content of latex and gas temperature on film structure and film permeability were investigated. It was found that water transfer played a dominant role in the spray coating process.
文摘Experimenial studies on active acoustic fiutter control are carried out successfully in wind-tunnel after the theoretical study The experdrients verify the theory presented in the reference[1] and give valuable experimeotal results which predict a prondsing future of applying new techology and new ideas to the area of vibration induced by flow.
基金supported by Division of Mathematical Sciences[grant number 1916467].
文摘Controlled experiments are widely used in many applications to investigate the causal relationship between input factors and experimental outcomes.A completely randomised design is usually used to randomly assign treatment levels to experimental units.When covariates of the experimental units are available,the experimental design should achieve covariate balancing among the treatment groups,such that the statistical inference of the treatment effects is not confounded with any possible effects of covariates.However,covariate imbalance often exists,because the experiment is carried out based on a single realisation of the complete randomisation.It is more likely to occur and worsen when the size of the experimental units is small or moderate.In this paper,we introduce a new covariate balancing criterion,which measures the differences between kernel density estimates of the covariates of treatment groups.To achieve covariate balance before the treatments are randomly assigned,we partition the experimental units by minimising the criterion,then randomly assign the treatment levels to the partitioned groups.Through numerical examples,weshow that the proposed partition approach can improve the accuracy of the difference-in-mean estimator and outperforms the complete randomisation and rerandomisation approaches.
文摘Agent-based modeling and controlled human experiments serve as two fundamental research methods in the field of econophysics. Agent-based modeling has been in development for over 20 years, but how to design virtual agents with high levels of human-like ＂intelligence＂ remains a challenge. On the other hand, experimental econophysics is an emerging field; however, there is a lack of experience and paradigms related to the field. Here, we review some of the most recent research results obtained through the use of these two methods concerning financial problems such as chaos, leverage, and business cycles. We also review the principles behind assessments of agents＇ intelligence levels, and some relevant designs for human experiments. The main theme of this review is to show that by combining theory, agent-based modeling, and controlled human experiments, one can garner more reliable and credible results on account of a better verification of theory; accordingly, this way, a wider range of economic and financial problems and phenomena can be studied.
文摘A kind of new acoustic liner with adjustable impedance has been proposed. At the same time, a set of control system has been designed for this kind of liner. Many experimental results have been obtained based on this control system. In fact, the present investigation shows the possibi1ity of active control of sound absorption coefficient or impedance of a liner according to external sound source condition by means of a standing wave tube. The experimental results show that the sound absorption coefficient of the liner can keep optimal under any sound source condition by controlling the cavity depth and the flow rate through the perforated plate of the liner. In addition, hoth the resistance and the reactance of the liner can also be controlled independently corresponding to any given condition. which is necessary to control unsteady How in turbomachinery.
文摘This paper is a quantitative analysis of the role of awareness in English prepositional structure learning in relation to Schmidt's noticing hypothesis about processing the target language form. The purpose is to identify the long-perplexing problem that Chinese students are reluctant to produce English prepositional structure in their writing. The research is a controlled experiment in a translation-based setting which provides empirical support for the claim that the level of awareness plays a crucial role in the learners' intake and written production the target form. The implication is that a more explicit pedagogical approach may be necessary.
基金the China Spallation Neutron Source project,the National Science Foundation of China(Grant Nos.11575289)the Key Laboratory of Particle Acceleration Physics&Technology and State Key Laboratory of Particle Detection and Electronics.
文摘Background The China Spallation Neutron Source(CSNS)accelerator consists of an 80 MeV H-LINAC,a 1.6 GeV rapid cycling synchrotron(RCS)and two beam transport lines.The uncontrolled beam may permanently damage the components or lead to very high residual radiation dose along the beam line.So the equipment protection must be deliberately designed and implemented.Purpose The machine protection system(MPS)protects components from being damaged by the beam.The response time requirement for the CSNS MPS is less than 20 ms,so the PLC(programmable logic controller)was adopted to implement the interlock logic.Methods The MPS was implemented as a two-tier architecture system,and developed through utilizing PLC and Experimental Physics and Industrial Control System(EPICS)software toolkits.The application logic was taken into careful consideration during the implementation stage.An embedded CPU module can function as an IOC accessing PLC I/O modules through the sequence CPU,with an embedded Linux operation system.Results The interlock logic and heartbeat functions were tested with all functions ok.Time consumption has been measured thoroughly since the important requirement,which is around 15 ms to stop the beam.Conclusions MPS was completed in Sep.2017 and then put into operation.It has been operating smoothly for more than 3 years.MPS has played an important role in every stage of CSNS’s commissioning and operation and achieved high reliability during the user’s experiment operation.The accelerator recently runs stably with low equipment failure.
基金funded by the Foundation ofYouth Innovation Promotion Association,CAS(No.Y202005)the Major achievements cultivation project of major scientific and technological infrastructure,CAS(No.NE01G74Y2)the National Natural Science Foundation of China(No.11805221).
文摘Purpose Hundreds of digital beam position monitor processors(DBPM)are required to be produced during the construction of projects such as High Energy Photon Source(HEPS)and the upgrade project of the Beijing Electron Positron Collider(BEPCII),which brings great challenges to the test work.In order to achieve accurate,fast,and complete mass production tests of DBPMs,an automatic test system(ATS)has been developed in this article.Methods According to the test items of DBPM,the standardized testing softwareflow is designed based on virtual instru-ment program control technology and experimental physics and industrial control system(EPICS),which realize automatic adjustment of test parameters and automatic acquisition of test result data.Results and conclusions The ATS can realize one-button testing of channel coefficients,channel linearity,attenuator linearity,beam current dependence(BCD)and sampling signal-to-noise ratio(SNR),and generate test reports.The total test time is less than 3 minutes,which is significantly more efficient compared to manual testing.More than 90 BEPCII DBPMs has been tested by this ATS in the lab.The test results proved that such a system could automatically recognize defective products and satisfy the requirements of mass testing.
