For purpose of simulation of the working characteristics of a new type offluid coupling shock absorber for vibration protection of sensitive equipment, a physical model ispresented by analyzing the internal fluid dyna...For purpose of simulation of the working characteristics of a new type offluid coupling shock absorber for vibration protection of sensitive equipment, a physical model ispresented by analyzing the internal fluid dynamic phenomenon with respect to the coupling shockabsorber and implemented in MATLAB software package. Using the model it is possible to evaluate theimportance of different factors for design of the shock absorber. In the meantime, the key-modelmachine is designed for coupling dynamic test. Comparisons with experimental results confirm thevalidity of the model. So the CAD/CAE software has been developed in MATLAB for design andexperimental test of the new coupling shock absorber.展开更多
Major Initiatives of 2015A.We made new strides in key areas of legislation The law is of great value in the governance of a country,and good laws are a prerequisite for good governance.Focusing on the key task of rais...Major Initiatives of 2015A.We made new strides in key areas of legislation The law is of great value in the governance of a country,and good laws are a prerequisite for good governance.Focusing on the key task of raising the quality of legislation,we channeled great effort into advancing legislation in key areas.Large in number,展开更多
The objectives of the study were to examine the effects of draught work on carcass characteristics, meat yield potential, and distribution along primal cuts in Hararghe highland bulls fed on net energy requirement bas...The objectives of the study were to examine the effects of draught work on carcass characteristics, meat yield potential, and distribution along primal cuts in Hararghe highland bulls fed on net energy requirement basis. Twelve bulls were sorted into three groups of four animals each and assigned to three treatment hours: control (0), 4, or 6, using a complete randomized design (CRD). The results of the study show that there are no significant differences (p > 0.05) in slaughter weight, hot carcass weight (HCW), chilling loss, total edible and non-edible offal, fat thickness (FT), deboned meat yield (kg), meat to bone ratio, muscle distribution, and proportion of kidney, pelvic, and heart fat (KPH%) among the treatment groups. However, the hot carcass-based dressing percentage was significantly lowered (p < 0.05) in bulls that work 4 or 6 hours a day. Meat yield was strongly correlated with HCW (r = 0.74) and FT (r = 0.73). Therefore, the number of hours the bull spent on draught work did not negatively impact meat yield or quality. Consequently, the research suggests that utilizing Hararghe highland bulls for draught service, four or six hours a day is viable for dual advantages: crop cultivation and marketable carcass.展开更多
The submersible pumping unit is a new type of pumping system for lifting formation fluids from onshore oil wells, and the identification of its working condition has an important influence on oil production. In this p...The submersible pumping unit is a new type of pumping system for lifting formation fluids from onshore oil wells, and the identification of its working condition has an important influence on oil production. In this paper we proposed a diagnostic method for identifying the working condition of the submersible pumping system. Based on analyzing the working principle of the pumping unit and the pump structure, different characteristics in loading and unloading processes of the submersible linear motor were obtained at different working conditions. The characteristic quantities were extracted from operation data of the submersible linear motor. A diagnostic model based on the support vector machine (SVM) method was proposed for identifying the working condition of the submersible pumping unit, where the inputs of the SVM classifier were the characteristic quantities. The performance and the misjudgment rate of this method were analyzed and validated by the data acquired from an experimental simulation platform. The model proposed had an excellent performance in failure diagnosis of the submersible pumping system. The SVM classifier had higher diagnostic accuracy than the learning vector quantization (LVQ) classifier.展开更多
Identifying risk factors for road traffic injuries can be considered one of the main priorities of transportation agencies. More than 12,000 fatal work zone crashes were reported between 2000 and 2013. Despite recent ...Identifying risk factors for road traffic injuries can be considered one of the main priorities of transportation agencies. More than 12,000 fatal work zone crashes were reported between 2000 and 2013. Despite recent efforts to improve work zone safety, the frequency and severity of work zone crashes are still a big concern for transportation agencies. Although many studies have been conducted on different work zone safety-related issues, there is a lack of studies that investigate the effect of adverse weather conditions on work zone crash severity. This paper utilizes probit–classification tree, a relatively recent and promising combination of machine learning technique and conventional parametric model, to identify factors affecting work zone crash severity in adverse weather conditions using 8 years of work zone weatherrelated crashes (2006–2013) in Washington State. The key strength of this technique lies in its capability to alleviate the shortcomings of both parametric and nonparametric models. The results showed that both presence of traffic control device and lighting conditions are significant interacting variables in the developed complementary crash severity model for work zone weather-related crashes. Therefore, transportation agencies and contractors need to invest more in lighting equipment and better traffic control strategies at work zones, specifically during adverse weather conditions.展开更多
A coupled electromechanical dynamic model for a working platform supported by an active magneticguide(AMG)is set up according to the special stiffness and damping theory of maglev system and theunique vibration of the...A coupled electromechanical dynamic model for a working platform supported by an active magneticguide(AMG)is set up according to the special stiffness and damping theory of maglev system and theunique vibration of the working platform for a machine tool.The dynamic characteristics of a workingplatform supported by an AMG are studied using different groups of control parameters.Results show thatthe dynamic characteristics of the platform system,such as critical vibration frequency,vibration modeand so on,can be improved by adjusting the control parameters.This research offers theoretical supportfor ultra-high-speed and ultra-precise machine working platform designs,including the structure of plat-forms,the design of electromagnets,and the establishment of the control parameters.展开更多
Objective: The purpose of this study is to examine the relationship between job characteristics (job autonomy,job feedback,skill variety,task identity,task significance) and work engagement of nurses in Malaysia.Metho...Objective: The purpose of this study is to examine the relationship between job characteristics (job autonomy,job feedback,skill variety,task identity,task significance) and work engagement of nurses in Malaysia.Methods: A survey using self-administered questionnaires was used to collect data from a sample of 856 staff nurses working in eight public hospitals in Malaysia.A shortened nine-item version of the Utrecht Work Engagement Scale(UWES-9) was used to measure work engagement.The UWES-9 comprises three dimensions,which was measured with three items each: vigor,dedication,and absorption.Job characteristics (job autonomy,job feedback,skill variety,task identity,task significance) were measured with the corresponding subscales of the Job Diagnostic Survey.Each subscale consisted of three items.Hypotheses were tested using hierarchical regression analysis.Results: Findings indicated that all the five demographic variables (age,marital status,education,organizational tenure,job tenure) were unrelated to work engagement.The results further revealed that job autonomy (β=0.19,P < 0.01),job feedback (β=0.10,P < 0.01),task identity (β=0.13,P < 0.01),and task significance (β=0.08,P< 0.05) were positively related to work engagement.Skill variety (β=0.03,P> 0.05),however,did not affect work engagement.Conclusion: Job autonomy,job feedback,task identity,and task significance are important factors in predicting work engagement.The findings of this study highlighted the need to incorporate these core dimensions in nursing management to foster work engagement.展开更多
The development of urbanization has led to an increase in the number and scale of construction projects and the types of building construction engineering are getting advance and diverse due to the rapid development o...The development of urbanization has led to an increase in the number and scale of construction projects and the types of building construction engineering are getting advance and diverse due to the rapid development of technology.One of them is the static pressure prestressed pipe pile which is the most commonly used technology in modern building construction work.It is mainly used for pile foundation in construction work,and it has the advantages in less pollution,low noise,and high efficiency compared to the traditional pile foundation.Study on the characteristics of static pressure prestressed pipe pile must be carried out and strengthened the research to increase the effectiveness and quality of static pressure prestressed pipe pile on construction works.This paper is mainly to analyzed the characteristic and construction technology of static pressure prestressed pipe piles on building construction work.展开更多
The traditional testing method of a hydraulic pump requires a large amount of test data from a variety of pump working conditions. The test is usually time-consuming and energy-consu- ming. And the accurate characteri...The traditional testing method of a hydraulic pump requires a large amount of test data from a variety of pump working conditions. The test is usually time-consuming and energy-consu- ming. And the accurate characteristic curves of the pump were hardly obtained due to a limited a- mount and discreteness of the test data. In order to simplify the test procedure and improve the test accuracy, a novel method for measuring hydraulic pump operating characteristic based on multi-ele- ment nonlinear regression (NLMR) modeling is proposed in this paper. The main idea of this model- ing method is establishing a mathematical model to predict the performance parameters of the hy- draulic pump, only a small amount of test data is needed. Consequently, the pump operating charac- teristics in any working conditions are obtained. And the test results of the pump are easily charac- terized in the graphs, charts, tables and so on. The evaluations of the model are carried out and dis- cussed in this paper. The result shows that the test error of the novel method can be controlled to be about 0. 1%. Compared with the traditional test method, the proposed method reduces greatly the test time and the random error of the test data, and improves the efficiency and accuracy of the pump test.展开更多
A new method of electrical discharge machining (EDM) in air-mixed medium—air-mixed EDM was presented, and comparative experiments were carried out to compare the machining characteristics of air-mixed EDM with conven...A new method of electrical discharge machining (EDM) in air-mixed medium—air-mixed EDM was presented, and comparative experiments were carried out to compare the machining characteristics of air-mixed EDM with conventional EDM. The experimental results showed that better machining performances were obtained with tool electrode as the cathode and workpiece as the anode. It was found that the material removal rate (MRR) was higher, the tool electrode relative wear ratio (TWR) was lower and the surface roughness (SR) quality was better in the case of air-mixed EDM than that of conventional EDM, and the reasons bringing out the results were analyzed.展开更多
Objective:This study aimed to determine the effects of job characteristics and work engagement on the nursing performance of nurses working in general hospitals.Methods:Data were collected from 169 nurses who are work...Objective:This study aimed to determine the effects of job characteristics and work engagement on the nursing performance of nurses working in general hospitals.Methods:Data were collected from 169 nurses who are working in a general hospital in South Korea by using a cross-sectional descriptive survey design.Results:Nurses’job characteristics and work engagement showed positive effects on nursing performance.This effect was magnified when work engagement was used as a mediating variable.Conclusions:The findings elucidate the factors influencing job performance and provide managers with important information for developing programs to improve the job skills and work engagement of nurses.展开更多
Proportional direction valve is one of the most fundamental elements in electronic-hydraulic control technique. Its function is to control the operating speed, direction, position, and strength of output force of the ...Proportional direction valve is one of the most fundamental elements in electronic-hydraulic control technique. Its function is to control the operating speed, direction, position, and strength of output force of the hydraulic actuator continuously. Considering the different application and the cost, the existing technique mainly includes the internal feedback valve used in open loop system, and the electronic closed loop controlled valve used in closed loop system. Because of their different mechanical structure and the gre at different in performance, it brings inconvenience for customer to select, also inconvenience for enterprise to produce. Aiming at this problem, the idea of combining the above two kinds of valves into one body is proposed first, and then the new valve's structure to realize this target is designed. The idea intends to apply the displacement pilot flow feedback control principle in present 2-position 2-way valve system to the proportional direction valve of 3-position 4-way system. Newly designed feed forward controller can decouple the interference between the internal feedback and the electronic closed loop. Redundant conversion is designed to electronic switch mode. Experiment on dynamic and static characteristic of new proportional direction valve in internal feedback control mode and electronic closed loop control mode is discussed to prove the new theory is correct. Although the new valve is of excellent dynamic response characteristic, its steady control characteristic in open loop control mode needs to be improved further. The research results prepare one new fundamental element for electronic-hydraulic control technology.展开更多
The partial opening of the working gate for a discharge tunnel is used more and more widely in the various conditions, such as releasing discharge to meet the needs of the various stages under construction, or of the ...The partial opening of the working gate for a discharge tunnel is used more and more widely in the various conditions, such as releasing discharge to meet the needs of the various stages under construction, or of the operations at low reservoir levels. In this article the hydraulic characteristics were investigated of the partial opening of the working gate based on the physical model experiments of the discharge tunnel for the Longtan Hydropower Project, including the discharge coefficient, the surface profile of the free flow section, the bottom pressure distribution of the tunnel with an aerator, the cavity length just from the ramp, and the wall pressure of the curve section of the outlet. Some new issues were discussed and the properties were presented of the partial opening of the gate.展开更多
Aiming at improving the capture performance of internal vortex electrostatic cyclone precipitator(ECP),a theoretical model with mechanics-electric-magnetic coupling was established,the collection efficiency of magneti...Aiming at improving the capture performance of internal vortex electrostatic cyclone precipitator(ECP),a theoretical model with mechanics-electric-magnetic coupling was established,the collection efficiency of magnetic confinement ECP under different working voltages was simulated,and the influence of magnetic flux intensity on the removal performance of submicron particles was explored.Results show that the number of particles escaped from the cyclone is greatly reduced after the introduction of magnetic field and electric field,indicating that charging effect and magnetic confinement are more conductive to trap submicron particles in the internal vortex ECP.The lower the working voltage is,the worse the charging lifting effect is,but the stronger the magnetic confinement characteristics are.Furthermore,the contributions of charging effect to collection efficiency and magnetic confinement characteristics are more obvious at a weaker magnetic flux density.The research results can provide a practical new idea for the innovative design of ECP.展开更多
Three characteristic points in the deformation history of a fractured tensile specimen are selected tocalculate two values of n( n1 and n2 ) to represent the hardening ability of material during the homogeneous plas-t...Three characteristic points in the deformation history of a fractured tensile specimen are selected tocalculate two values of n( n1 and n2 ) to represent the hardening ability of material during the homogeneous plas-tic deformation and the following large plastic deformation. Experimental results obtained with mild streel andred copper show that n determined using the three-point method proposed is better to describe the hardening a-bility of material. It is therefore concluded that three-point method can be used to describe the hardening prop-erty of material during both homogeneous deformation and large plastic deformation.展开更多
The research examines a new accreditation test system of English Test for International Communication(ETIC)launched in 2016 and developed by China Language Assessment(a professional testing service established by Beij...The research examines a new accreditation test system of English Test for International Communication(ETIC)launched in 2016 and developed by China Language Assessment(a professional testing service established by Beijing Foreign Studies Uni⁃versity).The analysis and discussion is conducted through an example procedure of such assessment performance on ETIC.The rel⁃evant review aims to sort out the theoretical framework and main characteristic of the system,address the consequence and decision elicited from the assessment,and conclude the contribution of ETIC as a task-ability assessment to the use of language.It shows the interpretation of ETIC is generalizable and relevant to make the decision for test users.Such test system of ETIC is accountable to the stakeholders for the intended use.The research also puts forward the direction of the language assessment in China.展开更多
基金This project is supported by National Defense Science Foundation of China(No.00J16.2.5DZ0502)and Provincial Natural Science Foundation of Guangxi of China(No.0141042).
文摘For purpose of simulation of the working characteristics of a new type offluid coupling shock absorber for vibration protection of sensitive equipment, a physical model ispresented by analyzing the internal fluid dynamic phenomenon with respect to the coupling shockabsorber and implemented in MATLAB software package. Using the model it is possible to evaluate theimportance of different factors for design of the shock absorber. In the meantime, the key-modelmachine is designed for coupling dynamic test. Comparisons with experimental results confirm thevalidity of the model. So the CAD/CAE software has been developed in MATLAB for design andexperimental test of the new coupling shock absorber.
文摘Major Initiatives of 2015A.We made new strides in key areas of legislation The law is of great value in the governance of a country,and good laws are a prerequisite for good governance.Focusing on the key task of raising the quality of legislation,we channeled great effort into advancing legislation in key areas.Large in number,
文摘The objectives of the study were to examine the effects of draught work on carcass characteristics, meat yield potential, and distribution along primal cuts in Hararghe highland bulls fed on net energy requirement basis. Twelve bulls were sorted into three groups of four animals each and assigned to three treatment hours: control (0), 4, or 6, using a complete randomized design (CRD). The results of the study show that there are no significant differences (p > 0.05) in slaughter weight, hot carcass weight (HCW), chilling loss, total edible and non-edible offal, fat thickness (FT), deboned meat yield (kg), meat to bone ratio, muscle distribution, and proportion of kidney, pelvic, and heart fat (KPH%) among the treatment groups. However, the hot carcass-based dressing percentage was significantly lowered (p < 0.05) in bulls that work 4 or 6 hours a day. Meat yield was strongly correlated with HCW (r = 0.74) and FT (r = 0.73). Therefore, the number of hours the bull spent on draught work did not negatively impact meat yield or quality. Consequently, the research suggests that utilizing Hararghe highland bulls for draught service, four or six hours a day is viable for dual advantages: crop cultivation and marketable carcass.
文摘The submersible pumping unit is a new type of pumping system for lifting formation fluids from onshore oil wells, and the identification of its working condition has an important influence on oil production. In this paper we proposed a diagnostic method for identifying the working condition of the submersible pumping system. Based on analyzing the working principle of the pumping unit and the pump structure, different characteristics in loading and unloading processes of the submersible linear motor were obtained at different working conditions. The characteristic quantities were extracted from operation data of the submersible linear motor. A diagnostic model based on the support vector machine (SVM) method was proposed for identifying the working condition of the submersible pumping unit, where the inputs of the SVM classifier were the characteristic quantities. The performance and the misjudgment rate of this method were analyzed and validated by the data acquired from an experimental simulation platform. The model proposed had an excellent performance in failure diagnosis of the submersible pumping system. The SVM classifier had higher diagnostic accuracy than the learning vector quantization (LVQ) classifier.
基金sponsored by the Federal Highway Administration(FHWA)in cooperation with the American Association of State Highway and Transportation Officials(AASHTO)
文摘Identifying risk factors for road traffic injuries can be considered one of the main priorities of transportation agencies. More than 12,000 fatal work zone crashes were reported between 2000 and 2013. Despite recent efforts to improve work zone safety, the frequency and severity of work zone crashes are still a big concern for transportation agencies. Although many studies have been conducted on different work zone safety-related issues, there is a lack of studies that investigate the effect of adverse weather conditions on work zone crash severity. This paper utilizes probit–classification tree, a relatively recent and promising combination of machine learning technique and conventional parametric model, to identify factors affecting work zone crash severity in adverse weather conditions using 8 years of work zone weatherrelated crashes (2006–2013) in Washington State. The key strength of this technique lies in its capability to alleviate the shortcomings of both parametric and nonparametric models. The results showed that both presence of traffic control device and lighting conditions are significant interacting variables in the developed complementary crash severity model for work zone weather-related crashes. Therefore, transportation agencies and contractors need to invest more in lighting equipment and better traffic control strategies at work zones, specifically during adverse weather conditions.
基金the National High Technology Research and Development Program of China(No2001AA423310)
文摘A coupled electromechanical dynamic model for a working platform supported by an active magneticguide(AMG)is set up according to the special stiffness and damping theory of maglev system and theunique vibration of the working platform for a machine tool.The dynamic characteristics of a workingplatform supported by an AMG are studied using different groups of control parameters.Results show thatthe dynamic characteristics of the platform system,such as critical vibration frequency,vibration modeand so on,can be improved by adjusting the control parameters.This research offers theoretical supportfor ultra-high-speed and ultra-precise machine working platform designs,including the structure of plat-forms,the design of electromagnets,and the establishment of the control parameters.
文摘Objective: The purpose of this study is to examine the relationship between job characteristics (job autonomy,job feedback,skill variety,task identity,task significance) and work engagement of nurses in Malaysia.Methods: A survey using self-administered questionnaires was used to collect data from a sample of 856 staff nurses working in eight public hospitals in Malaysia.A shortened nine-item version of the Utrecht Work Engagement Scale(UWES-9) was used to measure work engagement.The UWES-9 comprises three dimensions,which was measured with three items each: vigor,dedication,and absorption.Job characteristics (job autonomy,job feedback,skill variety,task identity,task significance) were measured with the corresponding subscales of the Job Diagnostic Survey.Each subscale consisted of three items.Hypotheses were tested using hierarchical regression analysis.Results: Findings indicated that all the five demographic variables (age,marital status,education,organizational tenure,job tenure) were unrelated to work engagement.The results further revealed that job autonomy (β=0.19,P < 0.01),job feedback (β=0.10,P < 0.01),task identity (β=0.13,P < 0.01),and task significance (β=0.08,P< 0.05) were positively related to work engagement.Skill variety (β=0.03,P> 0.05),however,did not affect work engagement.Conclusion: Job autonomy,job feedback,task identity,and task significance are important factors in predicting work engagement.The findings of this study highlighted the need to incorporate these core dimensions in nursing management to foster work engagement.
文摘The development of urbanization has led to an increase in the number and scale of construction projects and the types of building construction engineering are getting advance and diverse due to the rapid development of technology.One of them is the static pressure prestressed pipe pile which is the most commonly used technology in modern building construction work.It is mainly used for pile foundation in construction work,and it has the advantages in less pollution,low noise,and high efficiency compared to the traditional pile foundation.Study on the characteristics of static pressure prestressed pipe pile must be carried out and strengthened the research to increase the effectiveness and quality of static pressure prestressed pipe pile on construction works.This paper is mainly to analyzed the characteristic and construction technology of static pressure prestressed pipe piles on building construction work.
基金Supported by the National Science & Technology Pillar Program During the 12th Five-Year Plan Period(2014BAF08B06)the Research Foundation of Beijing Institute of Technology20110601061)
文摘The traditional testing method of a hydraulic pump requires a large amount of test data from a variety of pump working conditions. The test is usually time-consuming and energy-consu- ming. And the accurate characteristic curves of the pump were hardly obtained due to a limited a- mount and discreteness of the test data. In order to simplify the test procedure and improve the test accuracy, a novel method for measuring hydraulic pump operating characteristic based on multi-ele- ment nonlinear regression (NLMR) modeling is proposed in this paper. The main idea of this model- ing method is establishing a mathematical model to predict the performance parameters of the hy- draulic pump, only a small amount of test data is needed. Consequently, the pump operating charac- teristics in any working conditions are obtained. And the test results of the pump are easily charac- terized in the graphs, charts, tables and so on. The evaluations of the model are carried out and dis- cussed in this paper. The result shows that the test error of the novel method can be controlled to be about 0. 1%. Compared with the traditional test method, the proposed method reduces greatly the test time and the random error of the test data, and improves the efficiency and accuracy of the pump test.
基金the Post-doctor Foundation of Heilongjiang Province(Grant No.LBH-Z06139).
文摘A new method of electrical discharge machining (EDM) in air-mixed medium—air-mixed EDM was presented, and comparative experiments were carried out to compare the machining characteristics of air-mixed EDM with conventional EDM. The experimental results showed that better machining performances were obtained with tool electrode as the cathode and workpiece as the anode. It was found that the material removal rate (MRR) was higher, the tool electrode relative wear ratio (TWR) was lower and the surface roughness (SR) quality was better in the case of air-mixed EDM than that of conventional EDM, and the reasons bringing out the results were analyzed.
文摘Objective:This study aimed to determine the effects of job characteristics and work engagement on the nursing performance of nurses working in general hospitals.Methods:Data were collected from 169 nurses who are working in a general hospital in South Korea by using a cross-sectional descriptive survey design.Results:Nurses’job characteristics and work engagement showed positive effects on nursing performance.This effect was magnified when work engagement was used as a mediating variable.Conclusions:The findings elucidate the factors influencing job performance and provide managers with important information for developing programs to improve the job skills and work engagement of nurses.
基金supported by National Natural Science Foundation of China (Grant No. 50575156)Shanxi Provincial Natural Science Foundation of China (Grant No. 2008011053)
文摘Proportional direction valve is one of the most fundamental elements in electronic-hydraulic control technique. Its function is to control the operating speed, direction, position, and strength of output force of the hydraulic actuator continuously. Considering the different application and the cost, the existing technique mainly includes the internal feedback valve used in open loop system, and the electronic closed loop controlled valve used in closed loop system. Because of their different mechanical structure and the gre at different in performance, it brings inconvenience for customer to select, also inconvenience for enterprise to produce. Aiming at this problem, the idea of combining the above two kinds of valves into one body is proposed first, and then the new valve's structure to realize this target is designed. The idea intends to apply the displacement pilot flow feedback control principle in present 2-position 2-way valve system to the proportional direction valve of 3-position 4-way system. Newly designed feed forward controller can decouple the interference between the internal feedback and the electronic closed loop. Redundant conversion is designed to electronic switch mode. Experiment on dynamic and static characteristic of new proportional direction valve in internal feedback control mode and electronic closed loop control mode is discussed to prove the new theory is correct. Although the new valve is of excellent dynamic response characteristic, its steady control characteristic in open loop control mode needs to be improved further. The research results prepare one new fundamental element for electronic-hydraulic control technology.
基金the National Natural Science Foundation of China (Grant No. 50539060).
文摘The partial opening of the working gate for a discharge tunnel is used more and more widely in the various conditions, such as releasing discharge to meet the needs of the various stages under construction, or of the operations at low reservoir levels. In this article the hydraulic characteristics were investigated of the partial opening of the working gate based on the physical model experiments of the discharge tunnel for the Longtan Hydropower Project, including the discharge coefficient, the surface profile of the free flow section, the bottom pressure distribution of the tunnel with an aerator, the cavity length just from the ramp, and the wall pressure of the curve section of the outlet. Some new issues were discussed and the properties were presented of the partial opening of the gate.
基金sponsored by National Natural Science Foundation of China (Grant numbers 12172228,11572187)Natural Science Foundation of Shanghai (Grant number 22ZR1444400).
文摘Aiming at improving the capture performance of internal vortex electrostatic cyclone precipitator(ECP),a theoretical model with mechanics-electric-magnetic coupling was established,the collection efficiency of magnetic confinement ECP under different working voltages was simulated,and the influence of magnetic flux intensity on the removal performance of submicron particles was explored.Results show that the number of particles escaped from the cyclone is greatly reduced after the introduction of magnetic field and electric field,indicating that charging effect and magnetic confinement are more conductive to trap submicron particles in the internal vortex ECP.The lower the working voltage is,the worse the charging lifting effect is,but the stronger the magnetic confinement characteristics are.Furthermore,the contributions of charging effect to collection efficiency and magnetic confinement characteristics are more obvious at a weaker magnetic flux density.The research results can provide a practical new idea for the innovative design of ECP.
文摘Three characteristic points in the deformation history of a fractured tensile specimen are selected tocalculate two values of n( n1 and n2 ) to represent the hardening ability of material during the homogeneous plas-tic deformation and the following large plastic deformation. Experimental results obtained with mild streel andred copper show that n determined using the three-point method proposed is better to describe the hardening a-bility of material. It is therefore concluded that three-point method can be used to describe the hardening prop-erty of material during both homogeneous deformation and large plastic deformation.
文摘The research examines a new accreditation test system of English Test for International Communication(ETIC)launched in 2016 and developed by China Language Assessment(a professional testing service established by Beijing Foreign Studies Uni⁃versity).The analysis and discussion is conducted through an example procedure of such assessment performance on ETIC.The rel⁃evant review aims to sort out the theoretical framework and main characteristic of the system,address the consequence and decision elicited from the assessment,and conclude the contribution of ETIC as a task-ability assessment to the use of language.It shows the interpretation of ETIC is generalizable and relevant to make the decision for test users.Such test system of ETIC is accountable to the stakeholders for the intended use.The research also puts forward the direction of the language assessment in China.